Showing papers in "European Journal of Clinical Investigation in 1992"

A Taql polymorphism in the human interleukin-1β (IL-1β) gene correlates with IL-1β secretion in vitro

Abstract: In the present study we searched for restriction fragment length polymorphisms (RFLP) in the human interleukin-1 beta (IL-1 beta) gene and for correlations to monocyte (Mo) function in non-related healthy donors and insulin-dependent diabetic patients. We demonstrated a diallelic polymorphism with the restriction enzyme TaqI consisting of fragments of 9.4 kb and 13.4 kb. No differences in allele or genotype frequencies of this RFLP were observed between randomly selected controls and randomly selected patients with insulin-dependent diabetes mellitus (IDDM). However, when analysing IDDM patients negative for HLA-DR3 and -DR4, our data demonstrate that the 13.4 kb allele is more frequent in this group compared to a matched control group. The functional impact of this RFLP was studied by analysing in vitro stimulated Mo IL-1 beta response. An IL-1 beta allele dosage effect on secretory capacity was observed after LPS-stimulation: 13.4/13.4 kb homozygous individuals secreted significantly more IL-1 beta than 9.4/13.4 kb heterozygous individuals, who secreted significantly more than 9.4/9.4 kb homozygous individuals. Analyses of supernatants from LPS-stimulated Mo cultures from individuals with each TaqI IL-1 beta genotype revealed no differences in the mouse thymocyte co-stimulatory assay when compared on a molar basis, indicating that the TaqI polymorphism gave rise only to quantitative differences in expression levels and probably not to a mutant IL-1 beta.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucagon-like peptide-1 cells in the gastrointestinal tract and pancreas of rat, pig and man.

Abstract: A highly specific monoclonal antibody directed against the C-terminal part of glucagon-like peptide-1 (GLP-1) was raised to immunohistochemically evaluate the distribution of GLP-1 containing cells in the entire gastrointestinal tract including pancreas of rat, pig and man. In the pancreas GLP-1-immunoreactive cells were found variously shaped and predominantly located in the periphery of the islets. Ultrastructurally, GLP-1 was co-localized with glucagon in the alpha-granula of A-cells and was mainly restricted to the electrondense core. In the intestine open type cells reaching the lumen via a slender apical process were stained with the GLP-1 antibody. They occurred in all parts of the crypts but predominantly in the basal portion. The density of GLP-1 immunoreactive cells varied between species in a characteristic order: rat greater than pig greater than man. In pig and human gut a large number of cells occurred in the distal jejunum and ileum. A continuous increase of cell densities was found from the proximal to the distal colon resulting in highest numbers in the rectum. In rats the highest cell density occurred in the ileum. Again, a continuous increase of GLP-1-positive cell numbers was evident from the proximal to the distal portion of small and large bowel. GLP-1 was partly co-localized with PYY. The GLP-1 positive cells appeared electronmicroscopically as L-cells with the typical large granula. This morphological data indicates that GLP-1-releasing cells in the small intestine are appropriately positioned in the distal part to sense and respond to the presence of nutrients that have escaped the absorptive surface of the upper small intestine.

Plasma homocysteine before and after methionine loading with regard to age, gender, and menopausal status.

Abstract: Homocysteine is a probably atherogenic amino acid, the fasting and post-methionine load serum concentrations of which have been reported to be much lower in premenopausal women than in men and postmenopausal women. This difference has been proposed to explain the reduced proneness of premenopausal women to vascular disease. We measured both free and total plasma homocysteine concentrations both fasting and post-methionine load, in 169 healthy subjects. Twelve subjects (7%) had distinctly abnormal plasma homocysteine values. Among the remaining 157 subjects, neither fasting nor post-load values of free or total homocysteine were lower in premenopausal women (n = 46) than in men of similar age (n = 41) or postmenopausal women (n = 37). Fasting but not post-load values were lower in postmenopausal women than in men of similar age (n = 33), and lower among the women as a whole (n = 83) than among the men (n = 74). In men, fasting values increased with age, and paralleled age-related decreases in the concentrations of homocysteine metabolism cofactors (serum vitamin B12, blood folate, and plasma pyridoxal 5-phosphate). Both in men and in women, fasting total plasma homocysteine values were significantly and negatively correlated to serum vitamin B12 and blood folate concentrations. Whether the small differences in plasma homocysteine values between the present men and women may be a contributory factor vis-a-vis their different proneness to vascular disease has yet to be settled.

Hyperhomocysteinaemia in stroke: prevalence, cause, and relationships to type of stroke and stroke risk factors

Abstract: . Moderate hyperhomocysteinaemia is a frequent finding in atherothrombotic cerebrovascular disease. This study confirms and extends this observation. Hyperhomocysteinaemia was present in 57 of 142 survivors with stroke (40%) and in four of 66 controls (6%). Plasma homocysteine concentrations were increased not only in carotid artery disease or lacunar stroke but also in haemorrhagic or embolic strokes. Homocysteine values were unrelated to the presence of hypertension, smoking, or hypercholester-olaemia, or to the concentrations of blood glucose, glycosylated haemoglobin, and plasma fibrinogen. Multiple regression analysis of the patient data showed that about 40% of the variation in plasma homocysteine concentrations could be predicted by the values for the homocysteine metabolism cofactors, blood folate and plasma pyridoxal 5-phosphate and by renal function as reflected in the values for serum creatinine. In patients, urine excretion of homocysteine per unit creatinine was significantly increased and strongly correlated both to the plasma homocysteine concentration and to the values for blood folate, plasma pyridoxal 5-phosphate, and serum vitamin B12. We conclude that moderate hyperhomocysteinaemia is frequently present in cases of stroke, is independent of other stroke risk factors or the type of stroke, and is partly related to renal function and the concentrations of homocysteine metabolism cofactors.

Interleukin-8 and neutrophil activation in acute pancreatitis.

Abstract: It has been suggested that leucocytes play an important role in the pathogenesis of complicated pancreatitis. Indeed, increased plasma concentrations of neutrophil elastase as a marker of neutrophil activation could be detected in patients with a severe course of the disease. Recently, interleukin-8 (IL-8) has been described as a novel neutrophil activating peptide. To determine the role of IL-8 in acute pancreatitis we measured its serum concentrations by a specific enzyme-linked immunosorbent assay in 10 patients with acute pancreatitis daily during the first week of hospitalization. IL-8 levels were compared with plasma concentrations of neutrophil elastase and the clinical course of the disease. Three of the patients had uncomplicated pancreatitis, while seven showed various extrapancreatic complications. Patients with complicated pancreatitis had statistically significant (P less than 0.05) higher mean values of IL-8 (121 +/- 41 pg/ml-1 vs. 13 +/- 6 pg ml-1, mean +/- SEM) and neutrophil elastase (547 +/- 35 ng ml-1 vs. 250 +/- 20 ng ml-1) than patients with uncomplicated disease. There was a positive correlation (r = 0.52, P less than 0.0001) between IL-8 and neutrophil elastase in the lower concentration range of IL-8 (less than 100 pg ml-1). At IL-8 levels greater than 100 pg ml-1 neutrophil elastase was always greatly elevated; however, under these conditions the relationship between IL-8 and elastase was no longer linear. No measurable IL-8 concentrations were found when plasma elastase was less than 200 ng ml-1. During follow-up, initially elevated IL-8 concentrations decreased in correlation with clinical improvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-adrenergic receptors in human leukocyte subpopulations

Abstract: beta 2-Adrenergic receptors, which are encoded on chromosome 5q32-34, belong to the group of G-protein-linked hormone receptors with seven transmembrane domains. Upon agonist binding, adenylate cyclase is activated. Although the function of human leukocyte beta-adrenergic receptors is unknown, these cells are often used as a model system to study tissue beta-adrenergic receptors. In intact mononuclear leukocytes or membrane preparations, 1000-3000 beta 2-adrenergic receptors are found, having an antagonist affinity constant (KD) in the range of 25 pM. beta-Adrenergic receptor numbers are different in leukocyte subsets, with receptor density higher in B than in T cells. CD56+ or CD57+ natural killer cells express more receptors than CD8+ or CD4+ cells. KD is higher in CD8+ than in CD4+ cells. Acute sympathetic activation by isoproterenol infusion or short-lasting exercise leads to an increased number of mononuclear beta-adrenergic receptors with a slightly reduced proportion of those with high agonist affinity. Acute sympathetic activation by adrenaline infusion, short-term exercise, or psychological stress also causes a selective increase in circulating CD56+ or CD57+ lymphocytes which are rich in beta-adrenergic receptors. The results of several studies suggest that adrenaline-induced changes in beta-adrenergic receptors and the redistribution of leukocyte subsets may be linked. beta-Adrenergic receptors may mediate immuno-modulatory effects by causing selective cell mobilization.

The effects of dietary supplementation with n-3 polyunsaturated fatty acids in patients with rheumatoid arthritis: a randomized, double blind trial.

Abstract: Study objective: To determine the effect of dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFA) on disease variables in patients with rheumatoid arthritis. Design: Multicenter, ran- domized, placebo controlled, double blind. Setting: Three Danish hospital Departments of Rheumato- logy. Patients: Fifty-one patients with active rheuma- toid arthritis. Intervention: Random allocation to 12 weeks of treatment with either six n-3 PUFA capsules (3.6 g) or six capsules with fat composition as the average Danish diet. Main results: Significant im- provement of morning stiffness and joint tenderness. No significant effect on the four other assessed clinical parameters. No serious side effects. Conclusions: Die- tary supplementation with n-3 PUFA in patients with rheumatoid arthritis improved two out of six patient reported disease parameters. Further studies are needed to clarify the more precise role of n-3 PUFA in the treatment of rheumatoid arthritis.

Multi-frequency bioelectrical impedance augments the diagnosis and management of lymphoedema in post-mastectomy patients.

Abstract: The value of multiple frequency bioelectric impedence analysis (MFBIA) in the monitoring and management of post-mastectomy lymphoedema of the arm was evaluated in 15 patients and controls. The technique was found to produce quantitative agreement with a clinical diagnosis of lymphoedema and with the currently-used measure (limb volume calculated from circumferential measurements) of limb size. The significance of this finding lies in MFBIA being diagnostically informative: it indicates when an observed change in limb volume is directly, albeit theoretically, attributable to accumulation of extracellular fluid. MFBIA potentially offers the means for earlier definitive diagnosis and more-accurate monitoring of extracellular fluid changes during and after treatment.

1992 Mack Forster Award Lecture. Review. Regulation of angiogenesis in vitro.

Abstract: Angiogenesis is a morphogenetic process by which new capillary blood vessels are formed by sprouting from existing blood vessels. Angiogenesis is not only necessary for normal embryonic development and post-natal growth, but also occurs in adult life in a variety of physiological and pathological settings. Transient, regulated growth of new capillaries occurs during formation of the corpus luteum, wound healing, bone fracture repair, and myocardial ischemia. However, persistent, uncontrolled angiogenesis contributes to the pathogenesis of a number of diseases such as diabetic retinopathy and rheumatoid arthritis, and plays a crucial permissive role in the progressive growth and metastatic spread of tumours. In fact, one of the main reasons for the growing interest in this biological process has been the recognition that tumours are angiogenesis-dependent, requiring formation of new blood vessels recruited from the host to support their growth [l-41. Our understanding of the events leading to angiogenesis is still fragmentary and essentially descriptive in nature. Light and electron microscopic studies of growing capillaries have shown that the neovascularization process occurs via a series of sequential steps, which are similar regardless of the nature of the inducing stimulus. These steps can be summarized as follows: the endothelial cells that line existing microvessels focally degrade their investing basement membrane and form tiny sprouts which penetrate into the perivascular connective tissue [5 ] . As these sprouts elongate by migration of endothelial cells at their tip and proliferation of endothelial cells below the tip, a lumen is gradually formed [5,6]. The hollow sprouts thus generated anastomose with each other to form capillary loops through which blood begins to Bow. New sprouts then arise from each loop and eventually give rise to an entire capillary network [7]. The phenomenon of angiogenesis remained largely inaccessible to experimental analysis until the development of techniques allowing direct observation of the microvasculature in the living organism after the

Graves' immunoglobulins and cytokines stimulate the expression of intercellular adhesion molecule-1 (ICAM-1) in cultured Graves' orbital fibroblasts.

Abstract: Intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-asociated antigen-1 (LFA-1) are cell surface adhesion receptors that bind to one another and promote a variety of effector/target cell interactions in tissues affected by inflammatory or immune processes. Local infiltration of the thyroid gland and the retro-ocular space by mononuclear cells is a hallmark of Graves' disease and Graves' ophthalmopathy (GO). Thus, we studied the role of these adhesion receptors in the interaction of inflammatory cells with retro-ocular fibroblasts (OF) derived from patients undergoing transantral decompression for severe GO, and from normal individuals. Confluent OF-monolayers were incubated with various cytokines or protein-A affinity-purified IgGs prepared from sera of patients with severe GO, Hashimoto's thyroiditis (HT), rheumatoid arthritis (RA) and normal individuals. As determined by immunocytochemistry and immunoprecipitation using a monoclonal anti-ICAM-1 antibody, interleukin-1-alpha (IL-1a), tumour necrosis factor-alpha (TNFa) and interferon-gamma (IFNg) strongly enhanced surface expression of ICAM-1 in both GO- and normal OF. By contrast, Graves' IgGs stimulated ICAM-1 expression only in GO-, but not in normal OF. No effect was observed in either cell type with interleukin-2, transforming growth factor-beta, or IgGs from patients with HT, RA and normal individuals. Using phorbol ester-activated, 51Cr-labelled peripheral blood mononuclear cells (PBMCs) in a cell adhesion assay, we demonstrated potent adhesive activity of ICAM-1 in GO-OF pretreated with IL-1a, TNFa, IFNg or Graves' IgGs, while all other compounds did not affect PBMC adhesion to GO-OF.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone mineral density measured by dual-energy X-ray absorptiometry in normal men.

Abstract: A cross-sectional study of 222 healthy Finnish men aged 20-69 years was performed to establish reference values of bone mineral density (BMD) using dual-energy X-ray absorptiometry (DEXA). The effects of age, and of some physical and lifestyle factors on BMD of the lumbar spine and proximal femur (femoral neck, Ward's triangle and trochanter) were investigated. The maximal mean BMD was observed at the age of 20-29 years in all the measurement sites. Except for the trochanteric area, BMD diminished along with age, the over-all decrements being 4%, 11%, and 23% in the lumbar, femoral neck and Ward's triangle areas, respectively. BMD was in a positive relationship to weight and height in all the measurement sites. The adjusted (for age, height and weight) BMDs were higher (P less than 0.05) in the group of daily dietary calcium intake greater than 1200 mg as compared with the group of lowest calcium intake (less than 800 mg day-1) in the three femoral areas. Cigarette smoking or alcohol drinking had no obvious effect on BMD.

Noradrenergic and peptidergic innervation of secondary lymphoid organs: role in experimental rheumatoid arthritis.

Abstract: Noradrenergic (NA) and peptidergic nerve fibres are present in both primary and secondary lymphoid organs, distributing with the vasculature, trabecular and capsular smooth muscle, and within the parenchyma among cells of the immune system. NA nerve terminals directly abut lymphocytes and macrophages in spleen and lymph nodes. In these organs, norepinephrine has fulfilled the basic criteria for neurotransmission with cells of the immune system as targets. In vitro and in vivo studies have demonstrated NA modulation of primary and secondary antibody responses, cytotoxic T cell responses, natural killer cell activity, and proliferation and differentiation of both T and B lymphocytes. Substance P (SP) has been shown to modulate inflammatory responses, lymphocyte proliferation, and other immunologic reactivity. We investigated the role of NA and SP nerve fibres within lymph nodes in experimental allergic auto-immune arthritis in Lewis rats. Denervation of NA nerve fibres in popliteal and inguinal lymph nodes with 6-hydroxy-dopamine resulted in earlier onset and enhanced severity of arthritic changes as well as inflammation in bilaterally induced experimental arthritis, while denervation of SP nerve fibres in popliteal and inguinal lymph nodes with capsaicin resulted in delayed onset and diminished severity of the inflammatory changes ipsilaterally, and prevention of contralateral arthritic changes in unilaterally induced experimental arthritis. These findings suggest that NA and SP nerve fibres in lymph nodes can modulate the time course of onset and the severity of experimental arthritis in Lewis rats. These modulatory effects are distinctly different from the effects of NA and SP nerve fibres in the joints themselves.

Central obesity and hyperinsulinaemia in women are associated with polymorphism in the 5‘ flanking region of the human insulin gene

Abstract: Obesity is a multifactorial disease with a marked genetic component. The situation is further complicated by the heterogeneity of obesity demonstrated by the topographical distribution of body fat, e.g. upper body (central) and lower body (gluteal) obesity. Furthermore, the distribution of fat shows a stronger heritable tendency compared with total body fat. Central obesity is characterized by hyperinsulinaemia and insulin resistance, a feature in common with non-insulin dependent diabetes mellitus, hypertension and atherosclerosis. In order to study the molecular genetics of central obesity we have examined 56 severely obese (mean body mass index 40), unrelated British Caucasoid young non-diabetic women for associations of restriction fragment length polymorphism of candidate genes with anthropometric measurements and indices of insulin secretion and resistance. The candidate genes examined were insulin receptor, insulin sensitive glucose transporter and insulin. An association of the class 3 allele of the hypervariable region in the 5' flanking region of the insulin gene was found with upper segment obesity (P = 0.005). Furthermore, the class 3 allele was also associated with fasting hyperinsulinaemia (P = 0.01), stimulated insulin secretion (P = 0.01) and insulin resistance as calculated from the homeostatic model of assessment (HOMA; P = 0.008). No such associations were found with the other candidate genes studied. This data suggests that polymorphisms in the 5' flanking region of the insulin gene may affect expression of the gene and thereby modulate insulin production in severely obese female subjects.

Tumor necrosis factor alpha is associated with disease activity and the degree of anemia in patients with rheumatoid arthritis.

Abstract: . To elucidate the role of tumor necrosis factor alpha (TNF) in determining anemia of chronic disease (ACD) in rheumatoid arthritis (RA), 24 patients were studied for disease parameters, TNF serum levels and bone marrow for erythroid colony growth and compared with six controls. Serum TNFα was highest in ACD and correlated well with RA disease parameters. Both TNF and other RA disease parameters correlated inversely with degree of anemia. BFUe counts were lower in ACD, correlated positively with Hb and negatively with erythrocyte sedimentation rate (ESR). TNF reduced whereas anti-TNF upregulated in vitro erythroid colony counts. TNF production occurred in similar amounts in bone marrow cultures in the three groups. From these preliminary findings we conclude that ACD in RA correlates with by RA disease activity and that TNF may serve not only as an RA disease marker but also could be one of the factors mediating impaired erythropoiesis in ACD in active RA.

Supplementation with n-3 fatty acids reduces triglycerides but increases PAI-1 in non-insulin-dependent diabetes mellitus.

Abstract: The effects of dietary supplementation with n-3 fatty acids on lipid and glucose metabolism and on fibrinolysis were evaluated in 14 non-insulin-dependent diabetic patients who were given 10 g of MaxEPA (3 g n-3 fatty acids) or placebo (olive oil) per day in a randomized double-blind cross-over study during two consecutive 8-week periods. The serum triglyceride (TG) concentrations decreased by 27% (P < 0.01) after addition of MaxEPA with a reduction of VLDL TG by 36% (P < 0.05) while LDL cholesterol increased by 6% (P = 0.05). The fasting blood sugar and HbA1c concentrations increased significantly after addition of MaxEPA but the changes were not significantly different from those during the placebo period. The highest glucose concentrations at fasting and after an i.v. glucose injection were seen after MaxEPA while the serum insulin concentrations were unchanged. The peripheral insulin sensitivity, as measured by a euglycaemic, hyperinsulinaemic clamp technique, did not change during the study. The mean plasminogen inhibitor-1 (PAI-1) activity of the patients was elevated compared with healthy controls. In spite of the reduction of the triglyceride concentrations and unchanged insulin levels, there was a significant increase of the activity of PAI-1 (+21%, P < 0.01) after MaxEPA suggesting a possible impairment of the fibrinolytic capacity. In many situations there seems to be a reduction of PAI-1 when the triglycerides are lowered. In the diabetic patients given n-3 fatty acids this was not the case.

Regional effects and clearance of endothelin-1 across pulmonary and splanchnic circulation.

Abstract: . To determine the impact of i.v. endothelin-1 on systemic, pulmonary and splanchnic circulation, as well as the peptide's regional clearance, hepatic venous and right heart catheterization was performed in healthy volunteers. During the peptide's continuous i.v. administration (0.4 pmol x kg-1 x min-1, 60 min) its plasma concentration rose from 21±0.5 to 9.5 ± 5.3 pmol/1 (pulmonary artery), from 2.1±0.9 to 5.0±1.6 pmol/1 (femoral artery), and from 1.5 ± 0.6 to 2.9±1.2 pmol/1 (hepatic vein). This was accompanied by an increase in mean systolic arterial pressure from 127±14 to 131 ± 12mmHg(P<0.05). Concomitantly, cardiac output and heart rate decreased from 7.0 ±1.1 to 5.8 ±1.01/min and from 63 ± 6 to 56 ± 5 beats/min, respectively, while total vascular resistance increased from 964 ± 273 to 1204 ±338 dyn x cm x s-5 (P<0.01). No major changes in pulmonary circulation were observed, while splanchnic vascular resistance increased from 4472±1056 to 5361 ± 1420 dyn x cm x s-5 (P<0.01) and estimated hepatic blood flow decreased from 1403 ± 218 to 1218 ± 219 ml min-1 (P<0.01). During endothelin-1 infusion the pulmonary vascular bed accounted for approximately 53% of the peptide's overall disposal. Since the splanchnic area receives blood previously cleared during passage across the pulmonary vascular bed and the splanchnic plasma flow represented only 25 to 30% of the pulmonary plasma flow, the absolute amount of endothelin-1 disposed in the splanchnic region represented only about 3%. However, the regional fractional extraction rates were comparable (mean splanchnic fractional extraction: 35.5 ± 2.1 %; mean pulmonary fractional extraction: 49.2 ± 14.9%), and thereby indicate a potentially similar efficacy of the pulmonary and splanchnic vascular bed to extract endothelin-1. In conclusion we showed pulmonary clearance to be a main cause of the short half-life of endothelin-1 in man. Furthermore, the hemodynamic changes induced by the slight increases in regional concentrations of endothelin-1 provide evidence for a role of endothelin-1 in the regulation of circulation under (patho-) physiological conditions.

Identification in human urine of a natural growth inhibitor for cells derived from solid paediatric tumours.

Abstract: Partially purified urine of healthy human subjects contains several fractions able to inhibit the proliferation of cultured human neuroblastoma cells. One of the most active fractions was further analysed by gas chromatography-mass spectrometry and shown to contain genistein, a substance formed in the human body from precursors obtained by diet. Synthetic genistein was able to inhibit the proliferation of human neuroblastoma cells with a half-maximal effect at 5-10 mumol l-1 concentrations. Genistein displayed similar potencies in inhibiting the proliferation of cells derived from various other solid pediatric tumours. Our results suggest that genistein is a natural antineoplastic agent present in diet and that it could be useful for the therapy of paediatric tumours.

Relationship of insulin clearance and secretion to insulin sensitivity in non-diabetic Mexican Americans.

Abstract: . The antecedents of type II diabetes, while still controversial, are thought to involve decreased insulin sensitivity and compensatory hypersecretion of insulin. Mexican Americans have a three-fold excess risk of type II diabetes and non-diabetic Mexican Americans are characterized by hyperinsulinaemia and insulin resistance. Few data exist, however, on whether there are defects in insulin secretion and/or clearance in this population. We examined insulin sensitivity, secretion and clearance using combined insulin and C-peptide measurements analysed by the minimal model technique of Bergman and colleagues in 10 non-obese, normoglycaemic Mexican Americans and 11 age, sex and obesity-matched non-Hispanic whites. Mexican Americans had significantly decreased insulin sensitivity (S1 4.06 s. 7.56, P= 0.017), higher first phase insulin secretion (1.03 nM vs. 0.72 nM) and decreased insulin clearance (0.099 vs. 0.161) than non-Hispanic whites. Thus, normal Mexican Americans have higher rather than lower insulin secretion suggesting that lower insulin sensitivity may be an early defect in this ethnic group. In addition, they have reduced insulin clearance. Moreover, insulin sensitivity and insulin clearance were positively correlated. We thus speculate that decreased insulin clearance may represent a further autoregulatory mechanism in addition to increased insulin secretion to compensate for decreased insulin sensitivity.

Bone mass and biochemical parameters of bone metabolism in men with spinal osteoporosis.

Abstract: With advancing age both sexes have an increased incidence of osteoporotic fractures, although fractures are more common in women than in men. Whereas in women several potential risk factors have been identified, less is known about osteoporosis in men. A total of 27 Austrian men (mean age: 65 +/- 2 years) with atraumatic spine fractures were studied. In all patients, medical history gave no evidence of disease or medications causing osteoporosis. Peripheral bone mass was determined by single-photonabsorptiometry on the distal non-dominant forearm; lumbal bone density was measured by quantitative computed tomography. Serum levels of calcium, phosphate, alkaline phosphatase, osteocalcin, testosterone, estrogen, parathyroid hormone and 25-hydroxy-vitamin D as well as 2-h-urinary-OH proline and calcium excretion were measured. All data were compared with those of an age and sex matched control group consisting of 19 healthy males. A significant difference in mean peripheral and axial bone mass (SPA: P less than 0.004; QCT: P less than 0.0001) was observed between osteoporotic men and controls. When compared to controls, serum levels of alkaline phosphatase (P less than 0.012), urinary OH proline (P less than 0.05) and urinary calcium excretion (P less than 0.003) were significantly higher in the osteoporotic males. Additionally, there was a significant positive correlation between serum alkaline phosphatase and urinary OH proline excretion (r = 0.32; P less than 0.04) in the osteoporotics. All other biochemical parameters showed no significant differences. Our results may lead to the assumption that osteopenia in men is related to increased bone turnover.

Erythrocytes with covalently bound fibrinogen as a cellular replacement for the treatment of thrombocytopenia.

Abstract: Thrombocytopenia in general, and autoimmune thrombocytopenia in particular, is a disease of high prevalence with a non-satisfactory regime of treatment The present study aimed to explore the feasibility of an alternative treatment, based on the rationale that autologous erythrocytes modified to bear covalently bound fibrinogen would participate passively in the aggregation of the remaining platelets, thus augmenting the haemostatic needs, while resisting the autoimmune reaction directed towards the platelets Several procedures for the cross-linking of fibrinogen to red blood cells (RBCs) were tested Formaldehyde (33 microM) for 10 min at 23 degrees C attached 58 fibrinogen molecules per erythrocyte These erythrocytes were indistinguishable from untreated erythrocytes in the following properties: osmotic fragility, bound haemoglobin, sedimentation rate, acetylcholinesterase activity, phagocytosis by macrophages, rosette formation with K562 cells It is shown that RBCs cross-linked with fibrinogen are capable of participating in the in vitro aggregation of platelets and are indeed effective in the in vivo process of arrest of bleeding in an animal model of autoimmune thrombocytopenia

Correspondence between plasma mevalonic acid levels and deuterium uptake in measuring human cholesterol synthesis.

Abstract: . To assess the validity of two techniques capable of identifying immediate changes in human cholesterol production, plasma mevalonic acid levels and the rate of uptake of deuterium into plasma free cholesterol were compared in 5 healthy individuals over 48 h. The free-living subjects self-selected three meals per day prior to and during study. At t = 0, deuterium oxide was administered orally. Blood samples were collected before and every 4 h after dosing. Total cholesterol and mevalonic acid levels were determined in plasma at each timepoint. Deuterium enrichment changes in plasma free cholesterol, relative to plasma water content, were used to calculate free cholesterol fractional synthetic rates (FSR) at each timepoint. Total plasma cholesterol levels remained constant, whereas significant circadian rhythmicity was observed in both plasma mevalonic acid and deuterium uptake methods, with nadir and peak formation rates indicated at 14.00 to 16.00 h and about midnight, respectively. It is suggested that plasma mevalonic acid levels and free cholesterol deuterium uptake rate techniques are both suitable techniques for short-term measurement of human cholesterol synthesis.

Metabolic and neuroendocrine effects of pro-inflammatory cytokines.

Abstract: Immune-neuroendocrine interactions occur during physiological and pathological situations. Pro-inflammatory cytokines such as IL-1, IL-6 and TNF alpha play a role in mediating these interactions. Although all three cytokines can stimulate ACTH and glucocorticoid output, IL-1 has the highest potency. It is known that increased glucocorticoid levels result in hyperglycemia. However, administration of low doses of lipopolysaccharide (LPS), an inducer of several cytokines including those mentioned above, causes a profound and long lasting hypoglycaemia. This effect seems to be dissociable from that of insulin, since the same effect was observed in insulin-resistant db/db mice. The data reported here show that IL-1 plays a crucial role in the mediation of the hypoglycaemia induced by LPS, since other cytokines released following inoculation of endotoxin, such as TNF alpha and IL-6, have only marginal effects or do not induce hypoglycaemia when administered in doses similar to those of IL-1. The effect of IL-1 seems to be integrated at least in part at CNS level since i.c.v. administration produces hypoglycaemia in spite of the concomitant release of corticosterone. The data reported here reinforce the concept that IL-1 and related cytokines participate in the mediation of immune-neuroendocrine interactions.

Compositional analysis of the collagenous bone matrix. A study on adult normal and osteopenic bone tissue.

Abstract: The collagenous constituents of mature bone of 30 individuals 22-93 years of age were studied by post-mortem morphological and biochemical analysis. Morphometric evaluation of the second lumbar vertebral body revealed striking interindividual differences in bone mass, mean trabecular density and mean trabecular thickness. Collagen extracted from vertebral trabecular bone by limited pepsin digestion consisted mainly of collagen I (92%) and collagen V (8%). Immunohistochemistry revealed a distinct distribution of these two collagen types within the bone matrix. The degree of lysyl hydroxylation of the alpha 2(I) collagen chain correlated inversely with the trabecular bone volume (TBV) and with the mean trabecular plate density. This correlation was statistically significant for the entire study group as well as for the female and male subgroups. Within the female subgroup, the lysyl hydroxylation/TBV ratio was higher in postmenopausal than in premenopausal women and was highest in women with established osteoporosis. No significant correlation was found between the level of lysyl hydroxylation and the age of the patients. The alpha 1(I) collagen chain showed a nearly constant degree of lysyl hydroxylation in all 30 samples. The results provide convincing evidence that morphometric changes associated with osteopenia in adult bone are accompanied by an altered level of lysyl hydroxylation of the alpha 2(I)-chain of collagen I. The biochemical alterations observed may be responsible for the deposition of a deficient bone matrix in osteopenic conditions.

Postprandial control of gallbladder contraction and exocrine pancreatic secretion in man

Abstract: . To explore the interactions between chole-cystokinin (CCK) and the cholinergic system, we compared the effect of cholinergic or peptidergic CCK blockade on gallbladder contraction and pancreatic enzyme secretion using atropine and loxiglumide (a specific CCK antagonist) as pharmacological tools. Gallbladder contraction was measured by sonography and pancreatic secretion by a marker perfusion and aspiration technique. Graded doses of exogenous CCK8 induced dose-dependent contractions of the gallbladder and increasing enzyme outputs. Loxiglumide (10 mg kg-1 h-1) abolished the gallbladder response and prevented an increase in pancreatic enzyme secretion to CCK8. Atropine (5 μg kg-1 h-1), however, only reduced gallbladder contraction and enzyme output to CCK8. Gallbladder volumes decreased maximally to 12±4% after oral food, whereas enzyme output and plasma CCK levels increased 6- to 8-fold. Loxiglumide completely abolished gallbladder contraction and inhibited enzyme secretion by 30%. Atropine caused a small reduction in gallbladder volumes, but essentially blocked postprandial enzyme secretion. The results indicate that CCK is the major regulator of gallbladder contraction with the cholinergic system modulating the response, while the exocrine pancreas is crucially dependent on a cholinergic background with CCK modulating the secretory response.

Sustained high plasma 5-aminolaevulinic acid concentration in a volunteer: no porphyric symptoms.

Abstract: The pathogenesis of the acute porphyric attack is not known. One hypothesis is that porphyrin precursors, especially 5-aminolaevulinic acid (ALA), are toxic for neuronal tissue. This was tested by infusing ALA in a male volunteer after a loading dose at a rate of 50-80 mg h-1 for 92.5 h. During the experiment plasma ALA concentration was 9-11 mumol 1-l and porphobilinogen concentration 3-6 mumol 1-l which are the levels seen during acute attacks. Urinary excretion of these porphyrin precursors was also markedly increased. ALA infusion caused no subjective symptoms and no change in pulse rate, blood pressure, or autonomic nerve function or conduction velocity of peripheral nerves. Photosensitivity was not demonstrable. It is concluded that sustained high plasma ALA concentration does not cause porphyria-like symptoms.

Surfactant protein A (SP-A) is decreased in acute parenchymal lung injury associated with polytrauma.

Abstract: . To further investigate if the pulmonary surfactant system is altered in acute parenchymal lung injury of adults following polytrauma we measured SP-A level and phospholipid composition in 150 sequentially obtained lung lavage samples from poly-traumatized patients (n= 19) beginning at the day of trauma and ending 18 days later or when the patient was extubated. Out of the 19 patients studied 10 had severe parenchymal lung injury (ARDS), nine had moderate lung injury. SP-A was measured using a two-monoclonal sandwich ELISA-assay. Phospholipids were separated using high-performance liquid chromatography and their composition was calculated by comparison with standard phospholipid mixtures. We found immunoreactive SP-A concentrations ranging from 01 μg ml“‘ to 8–5 μg ml-1 lung lavage fluid obtained from all patients. The mean SP-A concentration in patients who had severe parenchymal lung injury (ARDS) was 1–06 ± 0.16 μg ml-1 lavage fluid, the mean concentration in patients who had only moderate parenchymal lung injury was 1.92 ± 0.18 μg ml-1 lavage fluid. Both concentrations were lower than in healthy controls (2.74 ± 0.3 μg ml-1 lavage fluid; n = 12). In patients who had moderate lung injury the SP-A level normalized, but in patients who had severe lung injury the SP-A level remained low during the timespan examined. SP-A alterations did not correlate to changes in phospholipid composition as determined in lung lavage samples of individual patients. We conclude that alveolar SP-A concentrations decrease in polytraumatized patients who have acute parenchymal lung injury soon after the trauma occurs. In patients who have lung injury of low severity the SP-A level normalizes with recovery, but with more severe parenchymal lung injury SP-A levels remain low. We speculate that the metabolic regulation of individual surfactant components might differ during lung injury and repair.

Prediction of bone loss in postmenopausal women

Abstract: Identification of women at greatest risk of future osteoporotic fracture could allow targeting of preventative therapy. The risk of spine, hip and vertebral fractures is related to bone mineral density [I], and bone density at the time of the menopause and the rate of bone loss thereafter are likely to be major predictors of future fracture. The potential to identify those women likely to lose bone most rapidly has developed dramatically over recent years as a result of improved biochemical and densitometric methods. There is some evidence that biochemical measurements can predict the rate of bone loss soon after the menopause [2,3]. Combinations of serum total alkaline phosphatase, urinary calcium, urinary hydroxyproline and serum osteocalcin, with an estimate of body fat content can predict about 60% of the variability in measured fractional bone loss in the ‘proximal distal’ forearm in early postmenopausal women. The potential usefulness of collagen derived biochemical markers of bone turnover remain to be established. In particular, the use of urinary pyridinium crosslinks as a specific and quantitative measure of bone resorption has aroused much interest [4]. The paper by Mole et al., in this issue of the Journal highlights the possible role of urinary oestrogens and pyridinium crosslinks in the prediction of bone loss from the distal forearm. They demonstrate that a combination of urinary pyridinoline, urinary oestradiol glucuronide and body mass index could explain up to 58% of the variation in bone loss in the forearm. Despite these encouraging developments, there is as yet no convincing evidence that the use of these measurements would provide a significant benefit in the context of a screening programme. The rate of bone loss at any particular skeletal site in the early postmenopausal period is of no importance per se. Biochemical measurements must predict long-term rates of bone loss, and risk of vertebral and femoral neck fractures decades after the menopause if their use to select women for preventative therapy can be justified. Several important questions remain to be answered. Perhaps the first question that should be asked is whether the pattern of postmenopausal bone loss

Nutritional behaviour and quality of life during oncological polychemotherapy: Results of a prospective study on the efficacy of oral nutrition therapy in patients with acute leukaemia

Abstract: A total of 29 patients with acute leukaemia were prospectively randomized before starting cytostatic treatment to be nourished either with intensified oral nutrition (intervention group) or ad libitum nutritional intake during the whole tumour therapy (median 22 weeks). All received menus of free choice (daily offer of 1.0-2.0 g protein, 30-50 kcal kg-1 body weight (BW)). Beyond this, intervention patients received nutrition education, daily visits by the dietician and record of food intake, as well as a weekly assessment of subjective well-being (linear analogue self assessment 'LASA'). From the LASA items, the factors: 'malaise', 'psychological distress', 'therapy side-effects' were extracted by principal component analysis, and correlated to nutrient intake and nutritional status. At the end of antineoplastic induction therapy, after continuous hospitalization of 10 weeks (median), 31.3% of the controls had regained their initial nutritional status, and 68.8% of the intervention group. Mean daily energy intake was 23.2 kcal kg-1 BW during weeks with weight loss (constant weight: 30.9, weight gain: 39.3 kcal kg-1 BW). Nutritional behaviour correlated with subjective well-being, low intake with complaints of tumour treatment side effects and weight loss with malaise.

Current concepts in the pathophysiology of hepatic encephalopathy.

Abstract: The mechanisms causing brain dysfunction in liver failure are still unknown. None of the various hypotheses of the pathogenesis of hepatic encephalopathy (HE) are generally accepted. Since brains of patients with HE cannot be studied with appropriate neurochemica1 or neurophysiological methods, data on cerebral function in HE are usually derived from animal studies. It is beyond the scope of this article to discuss each of the animal models in detail. However, it should be emphasized that these models reflect human disease only in certain aspects. Studies in humans concentrate on biochemical changes in body fluids, mostly in the blood. As the liver has a central role in metabolism it is not surprising that many changes will occur in liver failure. Concentrations of substances produced by the liver will decrease and those catabolised by the liver will increase. It is unknown whether such biochemical abnormalities reflect only decreased hepatic function or are also related to the development of HE. The following mechanisms may impair brain function in liver failure:

Haemodynamic and renal effects of urodilatin bolus injections in patients with congestive heart failure

Abstract: . Urodilatin (ANF(95–126)) is an analogue of the atrial natriuretic factor (ANF(99–126)), which has been isolated from human urine. Recently we have shown in healthy volunteers, that intravenous bolus injections of synthetic urodilatin produce more pronounced reductions of pulmonary arterial pressure than ANF(99–126). To compare haemodynamic and renal effects of synthetic urodilatin with those of ANF(99–126) in congestive heart failure (CHF), 12 patients (66.3 ± 1.4 years) received either two high dose intravenous bolus injections of 4 μg kg-1 bw Urodilatin (URO) at a 30 min interval (n= 6) or the same doses of ANF(99–126)(n = 6). Prior to i.v. URO, no URO immunoreactivity was found in human plasma (specific RIA, no crossreactivity to ANF). Similar to ANF, the increase in diuresis (1.4 ± 0.7 to 3.7+1.6 ml min-1) and natriuresis (169 ±114 to 430 ± 197 μmol min-1) was moderate after URO in CHF. During the 90 min study period, mean plasma cyclic GMP levels increased much more after URO (by 53.4 ±15.1 nM) than after ANF (by 13.1 ± 30 nM; P= 0.04). In contrast to ANF, i.v. bolus injections of URO produced sustained haemodynamic effects in CHF lasting up to 90 min: The average (0–90 min) reduction of systemic vascular resistance was more pronounced after URO (- 578 ± 148) than after ANF (- 204 ± 65 dyn*s*cm-5, P= 0.04). Average increase of stroke volume index (URO: 9.5 ±1.9; ANF: 2.8 ±1.4 ml min-1 m-2; P= 0.02) and reduction of pulmonary capillary wedge pressure (URO: — 10.8 ± 2.1; ANF: - 3.9 ± 1.6 mmHg; P= 0.03)were more prominent after URO. These data indicate that urodilatin bolus injections produce sustained beneficial haemodynamic effects in patients with congestive heart failure, which are prolonged and more pronounced than after ANF. The larger increase in plasma cyclic GMP levels in CHF suggests that in the cardiovascular system of heart failure patients, URO may induce a more potent stimulation of guanylate cyclase coupled ANF receptors than ANF(99–126).