Showing papers by "University of Perugia published in 1993"

Meticulous Prevention of Hypoglycemia Normalizes the Glycemic Thresholds and Magnitude of Most of Neuroendocrine Responses to, Symptoms of, and Cognitive Function During Hypoglycemia in Intensively Treated Patients With Short-Term IDDM

Abstract: To test the hypothesis that hypoglycemia unawareness is largely secondary to recurrent therapeutic hypoglycemia in IDDM, we assessed neuroendocrine and symptom responses and cognitive function in 8 patients with short-term IDDM (7 yr) and hypoglycemia unawareness. Patients were assessed during a stepped hypoglycemic clamp, before and after 2 wk and 3 mo of meticulous prevention of hypoglycemia, which resulted in a decreased frequency of hypoglycemia (0.49 ± 0.05 to 0.045 ± 0.03 episodes/patient-day) and an increase in HbA1c (5.8 ± 0.3 to 6.9 ± 0.2%) ( P

Generating Optimal Linear PLS Estimations (GOLPE): An Advanced Chemometric Tool for Handling 3D‐QSAR Problems

Abstract: An advanced variable selection procedure, called GOLPE, aimed at obtaining PLS regression models with the highest prediction ability is presented and illustrated with an application in 3D-QSAR. Key steps in the procedure are a preliminary variable selection by means of a D-optimal design in the loading space, and an iterative evaluation of the effects of individual variables on the model predictivity based on the validation of a number of reduced models, on variables combinations selected according to a FFD strategy. The procedure is successfully applied to a real 3D-QSAR case study: the results obtained by GOLPE are compared with those obtained by CoMFA and found to be in good agreement in terms of variable importance, but with a much higher prediction ability. Accordingly, the results encourage to think that it might be used within the CoMFA framework in the place of the present PLS version there, or in CoMFA-like studies on the structures generated by GRID probes.

PG-M1: A new monoclonal antibody directed against a fixative-resistant epitope on the macrophage-restricted form of the CD68 molecule

Abstract: A new anti-macrophage monoclonal antibody (PG-M1) was produced by immunizing BALB/c mice with fresh spleen cells from a patient with Gaucher's disease. PG-M1 reacts strongly with a fixative-resistant epitope of an intracytoplasmic molecule, selectively expressed by virtually all macrophages of the human body. Although attempts to immunoprecipitate the molecule recognized by PG-M1 have failed so far, the reactivity of the antibody with COS-1 and WOP cells transfected with a human complementary DNA clone encoding for the CD68 antigen suggests that PG-M1 is a new member of the CD68 cluster. However, unlike other CD68 antibodies (KP1, EBM11, etc.), which react with both macrophages and myeloid cells, PG-M1 detects a fixative-resistant epitope on the macrophage-restricted form of the CD68 antigen. In 957 routinely fixed, paraffin-embedded samples, PG-M1 showed a more restricted reactivity with elements of the monocyte/macrophage lineage than the previously described monoclonal antibodies MAC-387 (anti-calgranulins), KP1 (CD68) and Ki-M1P. Among hematological malignancies, PG-M1 only labels acute leukemias of M4 and M5 type and rare examples of malignant histiocytosis/true histiocytic sarcoma. In contrast, acute leukemias of the M1, M2, M3, M6, M7, and L1-L3 types, non-Hodgkin's lymphomas, and Hodgkin and Reed-Sternberg cells of Hodgkin's disease are consistently PG-M1-negative. In the daily diagnostic practice, PG-M1 seems to be particularly valuable for the diagnosis of myelomonocytic or monocytic leukemia and neoplasms of true histiocytic origin in routine paraffin sections.

Interleukin-4 and interleukin-10 inhibit nitric oxide-dependent macrophage killing of Candida albicans.

Abstract: Mouse peritoneal and splenic macrophages treated with interferon-gamma (IFN-gamma) and infected with the yeast Candida albicans expressed high fungicidal activity in vitro that correlated with increased nitrite concentrations in culture supernatants. Both effects were reduced by an inhibitor of nitric oxide (NO) synthesis which, in vivo, impaired the animals' ability to mount a footpad reaction and clear the fungus from infected organs. Because T helper type-2 (Th2) cytokines in candidiasis are known to limit the expression of protective Th1 functions, we tested the effect of interleukin (IL)-4 and IL-10 on candidacidal activity and NO production of IFN-gamma-activated macrophages. Fungal killing and NO secretion were inhibited, in a dose-dependent manner, by the two cytokines either separately or in combination. Impaired candidacidal activity was also demonstrable in the presence of monoiodoacetic acid, an inhibitor of phagocytosis. These data demonstrate that NO is involved in macrophage killing of C. albicans and support the notion that regulation of Th1 effector function by IL-4 and IL-10 might involve modulation of NO synthesis.

N-(4-Hydroxyphenyl)retinamide Induces Apoptosis of Malignant Hemopoietic Cell Lines Including Those Unresponsive to Retinoic Acid

Abstract: N-(4-Hydroxyphenyl)retinamide (HPR) is a synthethic retinoid of particular clinical interest in cancer chemoprevention. We have examined the in vitro effects of HPR on lymphoid and myeloid malignant cell lines and found that at concentrations between 10−5 and 3 × 10−7m it induces a dose-dependent growth inhibition (the peak plasma concentration in patients treated with HPR is 1 to 2 × 10−6m). The antiproliferative effect of HPR was, in all cell lines except K422, more potent than that induced by an equimolar dose of all-trans retinoic acid (RA). Also, this effect was irreversible on HL60 and DoHH2 cells that had been exposed to HPR (3 × 10−6m) for 24 h, but reversible on Raji and DHL4 exposed to the retinoid for 48 and 72 h, respectively. Time-course growth analysis showed that HPR at 3 × 10−6m or below induces a rapid fall of thymidine uptake and viability (>90%), whereas between 10−6 and 3 × 10−7m exhibits cytostatic effects. Interestingly, the RA-resistant HL-60R and NB306 cells, characterized by a point mutation in the retinoic acid receptor (RAR) and by the loss of the pml/RAR protein, respectively, were, like the parental RA-inducible HL-60 and NB4 cell lines, fully responsive to HPR, thereby suggesting that HPR and RA could act through different receptors or pathways. DNA flow-cytofluorimetric analysis revealed that HPR does not block cells in a specific phase of the cell cycle but triggers programmed cell death or apoptosis. This phenomenon was evidenced both by the visualization, on gel electrophoresis, of fragmented DNA, and by the “in cell” enzymatic labeling of DNA breaks with fluorescent dUTP. With the latter method, apoptotic cells become detectable by 6 h following exposure to 3 × 10−6m HPR. Ultrastructural examination of HPR-treated samples showed cells with chromatin compaction and cytoplasm condensation, characteristic of apoptotic cells. In conclusion, our study demonstrates that HPR suppresses malignant cell growth and induces apoptosis at pharmacologically relevant doses. The differential responsiveness by a number of cell lines, especially HL-60R and NB306, to HPR and RA indicates that these compounds may act through different receptors. The clinical use of HPR, particularly in retinoic acid-unresponsive acute promyelocytic leukemia patients, is suggested.

CD4+ subset expression in murine candidiasis. Th responses correlate directly with genetically determined susceptibility or vaccine-induced resistance.

Abstract: Previous work has shown that in hybrid (BALB/cCr x DBA/2Cr)F1 mice the development of a fatal disseminated disease by systemic infection with virulent Candida albicans is associated with the detection of strong Th2-like responses. However, a predominant Th1-like response and long-lived antifungal protection are induced by vaccinating these mice with live blastospores of attenuated C. albicans strains. When injected into DBA/2Cr mice, one such live vaccine strain was found in the present study to result in a progressive disease characterized by strong Th2 responses. Elevated serum IgG1, IgA, and IgE responses, weak or absent footpad reactions, sustained production in vitro of Th2 (IL-4 and IL-10) but not Th1 (IL-2 and IFN-gamma) cytokines by CD4+ cells, and eosinophilia were all detected in DBA/2 mice after infection with the attenuated vaccine. This was in marked contrast with the development of strong Th1 responses and persistent anticandidal protection in similarly infected, H-2-compatible BALB/cCr mice. Therefore, our data suggest that the type of Th response that predominates in mice after C. albicans infection correlates with genetically determined susceptibility or vaccine-induced resistance. Moreover, the genetic control of this resistance may not be associated with the H-2 complex.

Origin and domestication of the wine yeast Saccharomyces cerevisiae

Abstract: Recent ecological evidence points to a circulation model for Saccharomyces cerevisiae in nature which is different from that proposed at the end of the last century. The wine yeast ‘par excellence’ is isolated with extreme difficulty from conventional habitats, such as vineyard soil or the surface of ripe grapes, while it is almost the only species colonising the surfaces of the winery equipment.

Demonstration of a critical role for free fatty acids in mediating counterregulatory stimulation of gluconeogenesis and suppression of glucose utilization in humans.

Abstract: In vitro studies indicate that FFA compete with glucose as an oxidative fuel in muscle and, in addition, stimulate gluconeogenesis in liver. During counterregulation of hypoglycemia, plasma FFA increase and this is associated with an increase in glucose production and a suppression of glucose utilization. To test the hypothesis that FFA mediate changes in glucose metabolism that occur during counterregulation, we examined the effects of acipimox, an inhibitor of lipolysis, on glucose production and utilization ([3-3H]glucose), and incorporation of [U-14C]-alanine into glucose during insulin-induced hypoglycemia. Eight normal volunteers were infused with insulin for 8 h to produce modest hypoglycemia (approximately 3 mM) on two occasions, first without acipimox (control) and then with acipimox administration (250 mg per os at 60 and 240 min). Despite identical plasma insulin concentrations, glucose had to be infused in the acipimox experiments (glucose-clamp technique) to maintain plasma glucose concentrations identical to those in control experiments. Acipimox completely prevented counterregulatory increases in lipolysis so that during the last 4 h plasma FFA were below baseline values and averaged 67 +/- 13 vs. 725 +/- 65 microM in control experiments, P < 0.001. Concomitantly, overall glucose production was reduced by 40% (5.5 +/- 11 vs. 9.3 +/- 0.7 mumol/kg per min, P < 0.001), and gluconeogenesis from alanine was reduced by nearly 70% (0.32 +/- 0.09 vs. 1.00 +/- 0.18 mumol/kg per min, P < 0.001), while glucose utilization increased by 15% (10.8 +/- 1.4 vs. 9.3 +/- 0.7 mumol/kg per min). We conclude that FFA play a critical role in mediating changes in glucose metabolism during counterregulation, and that under these conditions, FFA exert a much more profound effect on hepatic glucose production than on glucose utilization.

Source of an egg kairomone for Trissolcus basalis, a parasitoid of Nezara viridula

Abstract: . The eggs of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), are successfully attacked by Trissolcus basalis (Woll.) (Hymenoptera: Scelionidae) and are recognized as hosts by a secretion applied to the egg chorion. This secretion is produced by the follicular cells in the proximal region of the ovariole of the female pentatomid and functions as an adhesive for attaching the eggs to the oviposition substrate. The adhesive and kairomone activity could be partially removed with water. This water extract elicited host recognition behaviour in T. basalis when applied to glass beads which stuck together as the extract dried. The adhesive and kairomonal activity was removed completely with acetone since acetone-washed host eggs were not recognized by T. basalis. Application of the acetone extract to glass beads stimulated ovipositional probes by T. basalis. The adhesive appeared to be composed of a mucopolysaccharide–protein complex.

Electrophoretic karyotyping as a taxonomic tool in the genus Saccharomyces.

Abstract: The electrophoretic karyotypes of strains of the ten species of the yeast genus Saccharomyces (sensu Vaughan-Martini & Martini 1992) were determined by the CHEF (contour-clamped homogeneous electric field) system of pulsed field gel electrophoresis. The number of bands was found to vary from 6 to 17 and the calculated molecular weights of haploid genomes ranged from 7.9 to 14.6 Mbp. The type strains of S. exiguus and the four species of the Saccharomyces sensu stricto complex (S. bayanus, S. cerevisiae, S. paradoxus and S. pastorianus) have genomes comprised of chromosomes of all three size classes: light ( 1,000 kb). Saccharomyces kluyveri DNA has only heavy bands, while the remaining species exhibit medium and heavy chromosomes. When more than one strain of each species was examined, it was seen that while the species S. bayanus, S. castellii, S. cerevisiae, S. kluyveri, S. paradoxus and S. pastorianus showed uniform karyotypes, S. dairensis, S. exiguus, S. servazzii and S. unisporus comprise heterogeneous taxa.

Shc products are substrates of erbB-2 kinase.

Abstract: The shc genes encodes three widely expressed proteins of 46, 52 and 66 kDa. Overexpression of p46shc and p52shc in NIH3T3 fibroblasts induces a tumorigenic phenotype. Shc products are phosphorylated on tyrosine by the activated epidermal growth factor receptor (EGFR) and become physically associated with EGFR via their SH2 domain. Thus Shc oncoproteins may play a role in mitogenic signal transduction. Here we report that Shc products are substrates also of the erbB-2 kinase and form complexes with the erbB-2 product in intact cells. In vitro, the bacterially expressed Shc SH2 domain is sufficient to reconstitute the high affinity Shc/erbB-2 interaction. The erbB-2 region required for Shc binding was narrowed down to the most COOH-terminal 179 residues of gp185erbB-2; within this region, phosphorylation of one or more of the erbB-2 autophosphorylation sites is required for Shc/gp185erbB-2 complex formation as well as optimal phosphorylation of Shc products by the erbB-2 kinase. Thus, Shc proteins may play a role in signal transduction by gp185erbB-2.

Physiological Increments in Plasma Insulin Concentrations Have Selective and Different Effects on Synthesis of Hepatic Proteins in Normal Humans

Abstract: These studies tested the hypothesis that physiological increments in plasma insulin concentrations have selective effects on the synthesis of hepatic proteins in humans. Leucine kinetics and fractional synthetic rates of albumin, fibrinogen, antithrombin III, and apoB-100 were determined in 6 normal subjects, on two different occasions during either the infusion of saline (control study) or a euglycemic-hyperinsulinemic (0.4 mU.kg-1 x min-1 for 240 min) clamp, by a primed-constant infusion of [1-14C]Leu. The insulin infusion significantly decreased the rates of nonoxidative Leu disposal (1.70 +/- 0.10 vs. control 2.06 +/- 0.09 mol.kg-1 x min-1), increased the albumin (7.2 +/- 0.4 vs. 6.2 +/- 0.6%/day), decreased the fibrinogen (18 +/- 1 vs. 23 +/- 2%/day), and antithrombin III (28 +/- 3 vs. 40 +/- 4%/day) fractional synthetic rate, whereas it did not affect the total apoB-100 (49 +/- 5 vs. 52 +/- 6%/day) fractional synthetic rate. Thus, the insulin-induced decrement in the estimates of whole-body protein synthesis (nonoxidative Leu disposal) represents the mean result of opposite effects of hyperinsulinemia on the synthesis of proteins with different functions. The positive effect of insulin on albumin synthesis may play an important anabolic role during nutrient absorption by promoting the capture of a relevant amount of dietary essential amino acids into the protein, whereas the negative effect of insulin on fibrinogen synthesis might, at least partially, account for the increased plasma fibrinogen concentrations previously reported in poorly controlled diabetic patients.

Oral 5'-methyltetrahydrofolic acid in senile organic mental disorders with depression: results of a double-blind multicenter study.

Abstract: 5′-Methyltetrahydrofolic acid (5′- MTHF) in addition to standard psychotropic medication significantly improved clinical recovery in depressed patients with borderline or definite folate deficiency, and significantly reduced depressive symptoms in elderly normofolatemic patients after 3 weeks of treatment. In this equivalence study the effect of 5′- MTHF on depressive symptoms and cognitive status was compared to Trazodone (TRZ) in normofolatemic elderly patients with mild to moderate dementia and depression. Ninety-six patients with dementia, scoring 12–23 at the Mini Mental State Examination (MMSE) and ≥18 at the Hamilton Depression Rating Scale (HDRS) after a 2-week placebo run-in, were randomized to receive either 5′-MTHF (50 mg/day p.o.) (47 patients) or TRZ (100 mg/day p.o.) (49 patients) in a double-blind design for 8 weeks. HDRS was assessed before, after 4 weeks and at the end of treatment; Rey’s Verbal Memory (RVM) test for immediate and delayed recall was evaluated before and after treatment. After 4 weeks of treatment HDRS score was reduced from 23±5 to 20±6 in the 5′-MTHF (p<0.05 vs baseline), and from 23±3 to 21±4 in the TRZ group (p<0.05 vs baseline). p]A further significant decrease to 18±6 and 19±5 respectively was obtained at the end of the treatment period (p<0.05 vs week 4) with 5′-MTHF and TRZ. HDRS was administered again after a 4-week, drug-free, follow-up period: no change vs the post treatment scores was observed either in the 5′-MTHF or in the TRZ group (18±7 and 19±5 respectively). RVM test for immediate recall was significantly improved (p<0.05) at week 8 vs baseline in the 5′-MTHF group whereas no significant change occurred in the TRZ group. No change in delayed recall was observed after treatment in either group. Tolerability was good for both treatments. This study shows that 5′-MTHF and TRZ are equally effective in improving depressive symptoms in patients with mild to moderate dementia and suggests that pharmacological doses of 5′-MTHF may exert psychotropic effects irrespective of folate status. (Aging Clin. Exp. Res. 1: 63–71, 1993)

c-fos mRNA is spontaneously induced in the rat brain during the activity period of the circadian cycle

Abstract: The basal expression of the proto-oncogene c-fos was studied by Northern blot analysis in different regions of the rat brain during 24 h. A striking spontaneous oscillation of c-fos mRNA expression was detected in animals kept in basal conditions with a 12 h light/12 h dark cycle. In these animals c-fos mRNA was just detectable during the rest hours (morning through afternoon), and was high during the activity hours (night). The periodicity of this oscillation persisted and became free-running when the animals were exposed for 6 consecutive days to constant light or darkness. It was thus demonstrated that the fluctuation of c-fos expression is circadian and is not created by the light-dark cycle, but the latter exerts a synchronizing effect. The oscillation of c-fos mRNA was modified by manipulations of the rest-activity cycle. In particular, the fluctuation observed in basal conditions was inverted, keeping the animals awake during the rest hours (diurnal) and allowing them to sleep in the activity period (nocturnal). These data indicated a close relationship between the oscillation of c-fos expression and the rest-activity cycle. Finally, electroencephalographic (EEG) monitoring was performed under behavioural control for 3 h before the animals were killed. These experiments confirmed that, irrespective of the time of day, the EEG pattern typical of a state of sleep (including both slow waves and paradoxical sleep) was associated with low or undetectable c-fos levels, whereas the protracted EEG desynchronization corresponding to wakefulness was associated with high c-fos expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Nocturnal blood glucose control in type I diabetes mellitus.

Abstract: A major problem in replacing insulin in type I diabetes mellitus is that currently no depot preparation exists that is capable of mimicking the background insulin secretion of the healthy pancreas. Because all of the currently available intermediate- or long-acting insulin preparations have a peaked-action profile, excess insulin action at midnight and insulin waning at dawn occur whenever such an insulin preparation is given at supper time. If the target fasting plasma glucose is the ambitious near-normoglycemia of intensive insulin therapy, intermediate-acting insulin at suppertime easily results in hypoglycemia in the early evening hours and hyperglycemia in the fasting state. The problems of overnight glycemia in type I diabetes are further complicated by the dawn phenomenon and the Somogyi phenomenon. The dawn phenomenon is the combination of an initial decrease in insulin requirements between approximately 2400 and approximately 0300, followed by an increase in the insulin needs between approximately 0500 and approximately 0800. The dawn phenomenon is the result of changes in hepatic (and extrahepatic) insulin sensitivity, which are best attributed to nocturnal growth hormone secretion. The dawn phenomenon is a day-to-day reproducible event that occurs in nearly all diabetic patients. Its contribution to fasting hyperglycemia correlates with diabetes duration (inversely) and the HbA1c percentage (directly). Overall, it is estimated that the specific contribution of the dawn phenomenon to fasting hyperglycemia is approximately 2 mM (approximately 35 mg/dl), but it may be much greater because of the warning of the depot-insulin preparation injected the previous evening. The Somogyi phenomenon, strictly speaking, refers to fasting hyperglycemia that occurs after inducement of nocturnal hypoglycemia by regular insulin. Because the present therapeutic regimens of NPH/Lente insulin given at suppertime cause overnight hyperinsulinemia, excessive fasting hyperglycemia rarely follows nocturnal hypoglycemia, except when excessive glucose is ingested to correct hypoglycemia. However, nocturnal hypoglycemia may easily deteriorate glycemic control later in the day, because it induces prolonged posthypoglycemic insulin resistance, which results in postbreakfast and late-morning hyperglycemia. With nocturnal insulin therapy, it is important to consider the problems of insulin pharmacokinetics, the dawn phenomenon, and the Somogyi phenomenon to prevent both nocturnal hypoglycemia and excessive fasting hyperglycemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Lymphotoxin, tumour necrosis factor and interleukin-6 gene transcripts are present in Hodgkin and Reed-Sternberg cells of most Hodgkin's disease cases

Abstract: Summary. Tissue specimens from 26 cases of Hodgkin's disease (HD) and six HD-derived cell lines were analysed for tumour necrosis factor (TNF), lymphotoxin (LT), and interleukin (IL)-6 RNA transcripts by in situ hybridization, in some cases subsequent to immunohistology for CD30 antigen. LT and TNF transcripts were found in tumour cells of all cases; IL-6 gene transcripts were detectable in 19/23 cases. Presence of RNA specific for these cytokines was not correlated with any of the following parameters: sex, symptoms and histotype, as well as immunophenotype and association of the tumour cells with Epstein-Barr virus. Rather, the presence of LT, TNF and IL-6 transcripts appeared to characterize Hodgkin and Reed-Sternberg cells in general, supporting concepts which suggest that HD represents a malignancy of cytokine secreting activated cells, and that many of the features distinguishing HD from other malignant lymphomas may ultimately be due to expression of cytokines. LT and TNF RNA transcripts were also found in five HD-derived cell lines, whereas supernatants of these cell lines contained high levels of LT, but low or undetectable levels of TNF activity. This suggests that, although not detectable at the level of RNA transcripts, differences between HD cases may exist on the level of cytokine gene transcript processing, translation and polypeptide secretion.

Inter-cohort differences in coronary heart disease mortality in the 25-year follow-up of the seven countries study.

Abstract: Sixteen cohorts of men aged 40-59 years at entry were examined with the measurement of some risk factors and then followed-up for mortality and causes of death for 25 years. These cohorts were located in the USA (1 cohort), Finland (2), the Netherlands (1), Italy (3), the former Yugoslavia (5), Greece (2), and Japan (2), and included a total of 12,763 subjects. Large differences in age-adjusted coronary heart disease (CHD) death rates were found, with extremes of 45 per 1000 in 25 years in Tanushimaru, Japan, to 288 per 1000 in 25 years in East Finland. In general, higher rates were found in the US and Northern European cohorts as compared to the Southern European and Japanese cohorts. However, during the last 10 years of follow-up large increases of CHD death rates were found in some Yugoslavian areas. Out of 5 measured entry characteristics treated as age-adjusted levels (serum cholesterol, systolic blood pressure, cigarette smoking, body mass index and physical activity at work), only serum cholesterol was significant in explaining cohort differences in CHD death rates. Over 50% of the variance in CHD death rates in 25 years was accounted for by the difference in mean serum cholesterol. This association tended to decline with increasing length of follow-up, but this was due to the great changes in mean serum cholesterol in the two Yugoslavian cohorts of Velika Krsna and Zrenjanin. When these two cohorts were excluded the association increased with time. Changes in mean serum cholesterol between year 0 and 10 helped in explaining differences in CHD death rates from year 10 onward. It can be concluded that this study suggests that mean serum cholesterol is the major risk factor in explaining cross-cultural differences in CHD.

Improved insulin action and glycemic control after long-term angiotensin-converting enzyme inhibition in subjects with arterial hypertension and type II diabetes.

Abstract: OBJECTIVE To determine the long-term effects of the angiotensin-converting enzyme inhibitor captopril on insulin sensitivity in subjects with type II diabetes and arterial hypertension. The chronic effects of angiotensin-converting enzyme inhibition on insulin-sensitive individuals are presently controversial. RESEARCH DESIGN AND METHODS Sixteen subjects, with type II diabetes (on diet and/or diet plus oral hypoglycemic agents) and arterial hypertension, were studied. During a 1-mo run-in period no antihypertensive drugs were administered, but oral hypoglycemic agents were continued in subjects already in therapy. The subjects were then randomly assigned to two 3-mo treatment periods, with either captopril or placebo (single blind, cross-over design). At the end of each treatment period, insulin sensitivity was assessed by means of a euglycemic-hyperinsulinemic clamp (2 sequential steps, 2-h each, insulin infusion 0.25 and 1 mU ·kg −1 ·min −1 , steps 1 and 2, respectively), combined with infusion of [3- 3 H]glucose (for calculation of hepatic glucose output and peripheral glucose utilization, rates of glucose disappearance), and indirect calorimetry (for calculation of glucose oxidation, nonoxidative glucose metabolism, and lipid oxidation). The percentage of HbA lc was measured to assess long-term glycemic control. RESULTS Comparing data at the end of placebo and captopril treatment, captopril resulted in: lower blood pressure (systolic 154 ± 2 vs. 163 ± 3 mmHg and diastolic 93 ± 2 vs. 101 ± 2 mmHg); greater insulin sensitivity in hyperglycemic conditions (total amount of insulin infused and time of insulin infusion required to reach euglycemia, 1.73 ± 0.54 vs. 2.08 ± 0.60 U and 58 ± 8 vs. 70 ± 11 min, captopril and placebo, respectively, P −1 · min −1 , step 1 of the clamp), muscle level (rates of glucose disappearance 26.1 ± 2.3 vs. 23.8 ± 2.1 μmol · kg −1 · min −1 , step 2 of the clamp), primarily attributable to ∼29% increase in nonoxidative glucose metabolism, and adipose tissue level (plasma free fatty acid 0.185 ± 0.03 vs. 0.24 ± 0.02 mM and lipid oxidation 1.9 ± 0.3 vs. 2.21 ± 0.04 μmol · kg −1 · min −1 in step 1); and lower HbA 1c (6.7 ± 0.2 vs. 7.3 ± 0.2%, P CONCLUSIONS Long-term captopril administration in type II diabetic subjects improves insulin sensitivity in the postprandial state, not in the fasting state, and improves glycemic control.

Antibodies to CD44 trigger effector functions of human T cell clones

Abstract: mAb against the lymphocyte homing receptor CD44/Hermes up-regulate the proliferation of human T PBL induced by anti-CD3 or anti-CD2 mAb. Moreover, certain anti-CD44 mAb can activate human resting T cells and mouse cytotoxic T cells in the absence of anti-CD3 or anti-CD2 mAb. Here, we show that anti-CD44 mAb trigger proliferation of human CD3+/CD4+ T cell clones in a fashion similar to that observed with mAb to CD3. Such an effect is IL-2-dependent, as shown by IL-2 production induced by anti-CD44 mAb and by complete inhibition of cell proliferation in the presence of anti-IL-2 antibodies or cyclosporin A. Moreover, anti-CD44 mAb trigger human cytolytic T cell clones to lyse Fc gamma-R+ P815 cells in the absence of additional stimuli. The magnitude of the cytolytic response induced by anti-CD44 mAb is comparable to that observed in the presence of anti-CD3 mAb for both CD4+ and CD8+ TCR-alpha/beta+ clones, and for V delta 1 or V delta 2 TCR-gamma/delta+ clones. By contrast, in CD3-/CD16+ NK cell clones, no cytolytic responses to anti-CD44 mAb could be observed. Granule trypsin-like esterase enzyme (granzyme) release by cytolytic T cell clones is induced by plastic-immobilized anti-CD44 mAb. Anti-CD44 mAb-triggered proliferation ([3H]thymidine incorporation) and cytotoxicity are blocked by the protein tyrosine kinase inhibitor, genestein. In addition, ligation of the CD44 molecule induces tyrosine phosphorylation of proteins identical, by molecular mass, to those phosphorylated after anti-CD3 mAb stimulation. Notably, anti-CD44 mAb does not induce tyrosine phosphorylation of a 21-kDa protein (the phosphorylated zeta-chain of the TCR molecular complex) typically observed upon anti-CD3 mAb stimulation. In conclusion, this study shows that the ligated CD44 molecule provides the necessary stimuli for a variety of T cell-mediated functions triggered via protein tyrosine kinase-dependent signal transduction pathways at least in part similar to those that follow stimulation of the CD3/TCR complex.

Impaired colonic motor response to cholinergic stimulation in patients with severe chronic idiopathic (slow transit type) constipation.

Abstract: Chronic idiopathic constipation, especially the slow transit type, is a troubling problem often afficting young women. The pathophysiological basis for this entity is unknown, although a defective cholinergic innervation has been postulated. We tested the hypothesis that cholinergic colonic innervation is deranged in this condition by studying colonic motor activity after strong cholinergic stimulation with edrophonium chloride in 14 women complaining of slow transit constipation. Unlike healthy subjects, constipated patients showed minimal or no response to edrophonium injection. It is concluded that in slow transit constipation there is an important alteration of colonic cholinergic activity and that edrophonium chloride may represent a useful test drug for colonic pathophysiological investigations.

Altered platelet function associated with the bronchial hyperresponsiveness accompanying nocturnal asthma

Abstract: Background: Nocturnal awakening is a common feature of bronchial asthma, and yet the mechanisms underlying this phenomenon are poorly understood. We investigated whether nocturnal awakening is associated with changes in platelet function with the use of a variety of markers of platelet activation. Methods: Ten patients with a history of nocturnal asthma and 10 age- and sex-matched healthy control subjects were studied at 10:00 PM, 4:00 AM, and 10:00 AM on 2 consecutive days. The following parameters were tested: forced expiratory volume in 1 second (FEV 1 ), log dose of methacholine inducing a 20% fall in FEV 1 , platelet count and volume, platelet aggregation induced by collagen or activating factor, and plasma and intraplatelet levels of β-thromboglobulin and platelet factor 4. Results: We have demonstrated that altered platelet function and platelet activation occurs at 4:00 AM in patients with nocturnal asthma and is associated with the maximum increases in bronchial reactivity. Such changes were not observed in 10 control subjects. Platelet dysfunction has been detected as a reduced aggregatory response of platelets to collagen and platelet activating factor such that up to 5 times more platelet activating factor and 1.5 times more collagen were required to elicit a threshold aggregatory response in asthmatic subjects when compared with control subjects; this difference was evident at all time points tested. Furthermore, at 4:00 AM there were significantly lower levels of intraplatelet β-thromboglobulin corresponding to the maximum reduction in peak expiratory flow and to the maximal increase in bronchial responses to inhaled methacholine. Conclusions: These results suggest that platelet activation accompanies nocturnal asthma and further suggest that platelets may play a role in this common clinical condition.