Showing papers by "Linköping University published in 1990"

Islet amyloid polypeptide: pinpointing amino acid residues linked to amyloid fibril formation.

Abstract: Islet amyloid polypeptide (IAPP), a putative polypeptide hormone, is a product of pancreatic beta-cells and the major constituent of the amyloid deposits seen mainly in islets of type 2 diabetic humans and diabetic cats. The connection between IAPP amyloid formation and diabetes is unknown, but a limited segment of the IAPP molecule, positions 20-29, seems responsible for the aggregation to fibrils. Differences in the amino acid sequence of this region probably determine whether or not islet amyloid can develop in a particular species. Amyloid fibril formation can be mimicked in vitro with the aid of synthetic peptides. With this technique we show that peptides corresponding to IAPP positions 20-29 of human and cat, species that develop IAPP-derived islet amyloid, form amyloid-like fibrils in vitro. The corresponding IAPP segment from three rodent species that do not develop IAPP-derived amyloid did not give rise to fibrils. Substitution of the human IAPP-(20-29) decapeptide with one or two amino acid residues from species without islet amyloid generally reduced the capacity to form fibrils. We conclude that the sequence Ala-Ile-Leu-Ser-Ser, corresponding to positions 25-29 of human IAPP, is strongly amyloidogenic and that a proline-for-serine substitution in position 28, as in several rodents, almost completely inhibits formation of amyloid fibrils.

Laser-Doppler flowmetry.

Abstract: Laser-Doppler flowmetry is a new method of the continuous and noninvasive measuring of the tissue blood flow, utilizing the Doppler shift of laser light as the information carrier. The method has already proved its potential usefulness in the clinical assessment of blood flow within disciplines such as dermatology, plastic surgery, and gastrointestinal surgery. In experimental medicine, laser-Doppler flowmetry has been used in the study of spontaneous rhythmical variations as well as in the study of spatial and temporal fluctuations in human skin blood flow. The method has facilitated further investigations of the nature of blood flow in a variety of tissue types. The method is rapidly spreading to many new applications in microvascular blood flow measurements. Several commercial laser Doppler instruments are available. This review article is a presentation of the state of the art of laser-Doppler flowmetry including theory, technology, and applications.

Chronic trapezius myalgia. Morphology and blood flow studied in 17 patients.

Abstract: Bilateral open biopsies from the painful upper part of the trapezius muscle were studied in 17 patients with localized chronic myalgia related to static load during repetitive assembly work. Isolat...

Quality of Life Concept and Assessment

Abstract: To understand and assess the concept "quality of life", it must be analyzed. In this report it is postulated that quality of life covers life as a whole as well as different subdomains of life. Life quality is defined as perceived global satisfaction and satisfaction within a number of key domains with special emphasis on well-being. A comprehensive chart of relevant life domains is presented and a flexible package of tested rating techniques outlined. In order to obtain valid and sensitive assessments, pincer operations with various types of ratings are recommended.

Proposed definitions for diagnosis, severity scoring, stratification, and outcome for trials on intraabdominal infection

Abstract: Analysis of the experience with scientific studies on patients with secondary intraabdominal infection has revealed that problems of interpretation and comparability between studies exist as they relate to variable diagnostic criteria, unmeasured severity of disease, and unclear outcome measures. A consistent system of definitions has been developed to address these deficiencies. Intraabdominal infection is defined as clinical peritonitis requiring both operative and microbiological confirmation for proof of infection. The APACHE II system is proposed for grading the severity of the infection and for stratification of patient risk of mortality. Mortality and time until death, on one hand, and recovery and time until recovery, on the other, are proposed as the main outcome measures, both being independently and positively defined. It is anticipated that this system of minimum rules will produce studies that can be compared, hence, accelerating knowledge and understanding about intraabdominal infection and its best treatment.

Glucocorticoid treatment in ileal Crohn's disease: relief of symptoms but not of endoscopically viewed inflammation.

Abstract: The effect of prednisolone (20-30 mg daily for six to nine weeks) was studied in eight patients with Crohn9s disease and recurrent, preanastomotic ileal inflammation, in respect of symptoms, endoscopic findings and phospholipase A2 activity in the ileal mucosa. The Harvey-Bradshaw Crohn9s disease activity index improved significantly, mainly because of reduced frequency of loose stools and diminution of abdominal pain. Endoscopy revealed no corresponding decrease in ileal inflammation, which in all cases persisted after treatment. The phospholipase A2 activity in the ileal mucosa was not altered by prednisolone. In two of three patients with concomitant colitis colonic inflammation improved. The study confirmed earlier reports of good symptomatic relief from glucocorticoid treatment in Crohn9s disease of the small bowel, but endoscopy suggests that this improvement was not the result of resolution of small intestinal mucosal inflammation.

Catalytic metals and field-effect devices—a useful combination

Abstract: The properties of gas-sensitive field-effect devices with catalytic metal gates are described. We demonstrate especially how the selectivity of these sensors depends on parameters such as the choice of catalytic metal, the structure of the catalytic metal film and the operation temperature of the device. The sensitivity towards molecules like hydrogen, ammonia, ethanol and ethylene is demonstrated. The selectivity pattern of devices with catalytic metal gates is discussed in relation to the fabrication of multisensor arrays and the development of 'artificial olfactory senses'.

Surface-state band structure of the Si(100)2×1 surface studied with polarization-dependent angle-resolved photoemission on single-domain surfaces

Abstract: The electronic structure of the Si(100)2\ifmmode\times\else\texttimes\fi{}1 surface has been studied with polarization-dependent angle-resolved photoemission. By using vicinal Si(100) samples, single-domain 2\ifmmode\times\else\texttimes\fi{}1 surfaces were obtained, and the surface-band dispersions were measured unambiguously along the symmetry axes \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{}' and \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{} in the surface Brillouin zone (SBZ). The obtained dispersions are compared to dispersions from earlier studies of two-domain surfaces, as well as to theoretical band-structure calculations. In addition to the well-known surface state attributed to the dangling bonds, five more surface-related structures were observed on the single-domain surface. One of these is the controversial surface state previously observed on two-domain surfaces at J\ifmmode\bar\else\textasciimacron\fi{}' in the [010] direction at \ensuremath{\sim}0.9 eV below the Fermi level (${\mathit{E}}_{\mathit{F}}$), which is not accounted for in any calculated surface band structure for the Si(100)2\ifmmode\times\else\texttimes\fi{}1 surface. Contrary to a previous report, it is also observed on the single-domain surface at several points in the SBZ.The second additional structure was found to disperse downwards along the \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{}' line, to a minimum energy of 3.4 eV below ${\mathit{E}}_{\mathit{F}}$ at J\ifmmode\bar\else\textasciimacron\fi{}'. It is interpreted as a back-bond resonance. The third additional structure was seen as a faint peak at the Fermi level in normal emission. Finally, two other surface-related structures were found in the \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{} direction, one at \ensuremath{\sim}-1.3 eV at \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{} in the second SBZ, splitting into two peaks for higher ${\mathbf{k}}_{\mathrm{?}}$ values. By using a linearly polarized light source, the symmetry properties of the surface states and resonances were determined along the symmetry axes \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{}' and \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{} in the SBZ. The polarization dependence for several states indicates a mirror symmetry along these directions, with the dangling-bond state having even parity in both directions, in agreement with theoretical predictions for symmetric dimer models, and the back-bond resonance having odd parity in the \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{}-J\ifmmode\bar\else\textasciimacron\fi{}' direction. Three of the surface states and resonances are not accounted for in theoretical band structures for the 2\ifmmode\times\else\texttimes\fi{}1-reconstruction. Two of these can be explained by domains of asymmetric dimers, arranged into c(4\ifmmode\times\else\texttimes\fi{}2) or p(2\ifmmode\times\else\texttimes\fi{}2) periodicities.

Colon cancer, physical activity, and occupational exposures. A case‐control study

Abstract: A case-control study on colon cancer was conducted encompassing 329 cases and 658 controls. Occupations and various exposures were assessed by questionnaires. A decreased risk was found in persons with physically active occupations. This effect was most pronounced in colon descendens and sigmoideum with an odds ratio (OR) of 0.49 whereas no reduced risk was found for right-sided colon cancer. Regarding specific jobs, reduced ORs were found for agricultural, forestry, and saw mill workers and increased OR for railway employees. High-grade exposure to asbestos or to organic solvents gave a two-fold increased risk. Regarding exposure to trichloroethylene in general, a slightly increased risk was found whereas such exposure among dry cleaners gave a seven-fold increase of the risk.

Does Physical Exercise Influence the Frequency of Postmenopausal Hot Flushes

Abstract: The frequency of moderate and severe hot flushes was investigated in a group of women (n=142) who took part in organized physical exercise on a regular basis, and a control group of all women 52 and 54 years old in the city of Linkoping, Sweden (n = 1,246). Only women with natural menopause and without a history of hormonal replacement treatment were statistically compared in the study. It appeared that moderate and severe vegetative symptoms with hot flushes and sweatings were only half as common among the physically active postmenopausal women (21.5%) as in the control group (43.8%). Although this could be due to a positive selection of these physically active women, it might also be due to the fact that exercise may affect the mechanisms that elicit hot flushes in peri- and postmenopausal women.

A unified single-phase clocking scheme for VLSI systems

Abstract: Two of the main consequences of advances in VLSI technologies are increased cost of design and wiring. In CMOS synchronous systems, this cost is partly due to tedious synchronization of different clock phases and routing of these clock signals. Here, a single-phase clocking scheme that makes the design very compact and simple is described. It is shown that this scheme is general, simple, and safe. It provides a structure that can contain all components of a digital VLSI system, including static, dynamic, and precharged logic as well as memories and PLAs. Clock and data signals are presented in a clean way that makes VLSI circuits and systems well suited for design compilation. >

Kidney IGF-I mRNA in initial renal hypertrophy in experimental diabetes in rats

Abstract: It has recently been demonstrated that immunoassayable kidney insulin-like growth factor I concentration increases 24–48 h after induction of diabetes, preceding the initial renal hypertrophy. To elucidate whether this increase is due to increased local production we studied rat kidney insulin-like growth factor I gene expression during the first four days after induction of streptozotocin diabetes. Eighteen hours after injection with streptozotocin the diabetic animals were divided into two groups, one of which was treated with insulin, and daily for four days animals from each group were taken out for investigation. After four days the wet kidney weight had increased from baseline by 20% (from 687±23 to 827±6mg (mean±SEM), p < 0.01) in the untreated diabetic group, while no significant increase occurred in the insulin-treated group (687±23 vs 732±21 mg, NS). Kidney insulin-like growth factor I increased rapidly from baseline, the rise amounting to 52% after 48 h (from 271±11 to 411±32 ng/g, p < 0.01) with a decline to control level on day four in the untreated diabetic group. Kidney insulin-like growth factor I remained unchanged in the insulin-treated diabetic group. Insulin-like growth factor I mRNA was measured by solution-hybridization assay. No differences were found in kidney insulin-like growth factor I mRNA between the two diabetic groups over the study period, while in liver, insulin-like growth factor I mRNA tended to be lower on day four in diabetic rats when compared to insulin-treated rats (p=0.07). These results show that the increase in kidney insulin-like growth factor I during initial renal hypertrophy in experimental diabetes is not associated with an elevated level of kidney insulin-like growth factor I mRNA and suggest that other, possibly translational, mechanisms are responsible for insulin-like growth factor accumulation in the kidney.

Screening for carcinoma of the prostate by digital rectal examination in a randomly selected population.

Abstract: OBJECTIVE--To study the acceptability, costs, psychosocial consequences, and organisation of screening for carcinoma of the prostate. DESIGN--A randomly selected population was personally invited for digital rectal examination by a urologist and a general practitioner. Further examinations were performed if induration was felt. Each man completed a questionnaire on his response to the examination. SETTING--General practices in the area of Norrkoping. PATIENTS--1494 Men aged 50-69 randomly selected from a population of 9026. MAIN OUTCOME MEASURE--Prostates having a firm nodular consistency. RESULTS--Carcinoma of the prostate was suspected in 45 of 1163 patients examined; in 10 by the general practitioners, in 10 by the urologists, and in 25 by both. Forty four men had a fine needle aspiration biopsy, and carcinomas were found in 13 cases. Of these, one had been suspected by the general practitioner, four by urologists, and eight by both. The cost for each man was 11.60 pounds, and the cost for each case of carcinoma detected and treated by potentially curative methods was 2477 pounds. Of the 13 men with carcinoma, 10 underwent radical prostatectomy and one radiotherapy. One man had advanced disease and was given endocrine treatment, another was not treated. Only 193 men felt distress during the initial examination. Of the 44 men who had an aspiration biopsy, 25 experienced anxiety. CONCLUSIONS--Screening for carcinoma of the prostate by a urologist or a general practitioner using digital rectal examination is a cost effective method of early diagnosis. Whether such screening leads to prolonged survival, however, remains doubtful.

The GP's dilemmas: a study of knowledge need and use during health care consultations.

Abstract: For use in system development, a method based on both qualitative and quantitative data was employed to study the difficulties--the dilemmas--a general practitioner (GP) faces during daily consultations. Video recordings were used for stimulated recall of the consultation. From 46 consultations, 262 dilemmas were identified by the 12 GPs involved. Medical dilemmas were encountered during three out of four consultations. Dilemmas in the communication with the patient occurred during two consultations out of three, while dilemmas in the organizational environment and dilemmas challenging the GP's personal competence occurred during one consultation out of three, respectively. A phenomenological analysis of the comments showed that few dilemmas were described as problems during "hypothetico-deductive reasoning". In many cases the GP found it difficult to understand the situation as a whole. Based on these qualitative data, a model of the GP's management of ill-structured complex dilemmas is discussed and proposed, to be taken into account in the development of decision support systems for outpatient practice.

Chronic pancreatitis: Results of operations for relief of pain

Abstract: Pancreaticojejunostomy is the method of choice for surgical treatment of pain in chronic pancreatitis in the case of ductal dilation. The operative risk is small and all remaining glandular tissue preserved. At 5 years postoperatively, about two-thirds of the patients still experience pain relief.

Effect of an educational program for general practitioners on Gotland on the pattern of prescription of psychotropic drugs

Abstract: During the years 1983–1984, an educational program was given to all general practitioners on the island of Gotland. This report evaluates changes in prescription habits from 1982 to 1985. To correct for general trends that occurred simultaneously, the prescription habits were compared to the habits in the rest of Sweden. Both on Gotland and in Sweden as a whole, the use of antidepressants increased from 1982–1985, but significantly more on Gotland. In 1982, the use of antidepressants was low on Gotland, 54% of that in the rest of Sweden. After the educational programs, Gotland reached 77% of the use in the rest of Sweden. In 1982, the use of lithium was 123% of that in the rest of Sweden. After the educational programs, the use of lithium was unchanged, and a small increase of 5.6% was seen in the rest of Sweden. After the educational programs, the prescription of sedatives on Gotland decreased (– 8.2%), and an increase of 4.5% was seen in the rest of Sweden. The use of major tranquilizers also decreased significantly (– 23%) on Gotland. Even in the rest of Sweden, a significant but much smaller decrease was seen: – 13%. On Gotland the frequency of hypnotics remained stable from 1982–1985, and a significant increase was seen in the rest of Sweden.

Soft tissue sarcoma and occupational exposures.

Abstract: The associations between soft tissue sarcoma (STS) and occupational exposures were studied in a case-referent study in the southeast of Sweden. Exposure information was obtained through mailed questionnaires to 96 cases, 450 randomly selected population referents, and 200 cancer referents. Odds ratios (OR), were calculated for various occupational groups, and particularly, for occupations with potential exposure to chlorinated phenoxy herbicides and chlorophenols. In the analyses based on population referents, increased risks for soft tissue sarcoma were seen for especially gardeners (OR = 4.1), but also railroad workers (OR = 3.1); construction workers with exposure to impregnating agents (OR = 2.3), asbestos (OR = 1.8), or pressure impregnating agents (OR = 1.7); and unspecified chemical workers with potential exposure to phenoxy herbicides and/or chlorophenols (OR = 1.6). A similar pattern appeared when cancer referents were used although the numerical values of the odds ratios became different. A grouping of jobs resulted in Mantel-Haensel OR from 1.5 to 1.9 for farmers and forestry workers, dependent on referents used and even more increased OR for railroad workers and unspecified chemical workers with potential exposure to phenoxy herbicides and chlorophenols. The results of the study confirm rather than refute that phenoxy herbicides and chlorophenols could be of etiologic importance for STS; the high risk for gardeners, although based on a small number of individuals, was unexpected and remains unclear. Also, since other cancers were used as referents, no definite problems of recall bias should obtain in this material. None of the exposed groups had a higher proportion of smokers than the unexposed group.

Evaluation of a multiple gas mixture with a simple MOSFET gas sensor array and pattern recognition

Abstract: The properties of a gas sensor array can be improved by the use of pattern recognition (PARC) methods. A gas sensor array with three pairs of Pd-gate MOSFETs and Pt-gate MOSFETs is exposed to a multiple-component gas mixture. Each pair is operated at a different temperature. The signals from the six sensors are analysed with both linear and nonlinear PLS (partial least square) models. The calculations of the PLS models are based on sensor signals obtained from calibration experiments. By means of combining a pattern recognition method with a semiconductor-based gas sensor array, we show that hydrogen concentrations can be predicted well in the presence of three other interfering gases.

Early antibiotic treatment of reactive arthritis associated with enteric infections: clinical and serological study.

Abstract: OBJECTIVE--To find out whether a 10-14 days' course of antibiotics early in the course of reactive arthritis associated with enteric infections could reduce the severity and duration of the disease and whether the antibody response in patients with reactive arthritis associated with yersinia infection differed between those treated and those not treated with the antibiotics. DESIGN--Prospective multicentre trial in which patients were randomised to treatment or no treatment with antibiotics. Patients were seen at three and six weeks and three, six, nine, 12, and 18 months after their first visit. SETTING--Departments of infectious diseases in three hospitals in Linkoping, Malmo, and Stockholm, Sweden. PATIENTS--40 Consecutive patients who had had symptoms of reactive arthritis associated with enteric infection for less than four weeks. INTERVENTIONS--20 Patients were allocated to treatment with antibiotics and 20 patients did not receive antibiotics. All patients received non-steroidal anti-inflammatory drugs, and four also received intra-articular steroid injections after at least six weeks' observation. MAIN OUTCOME MEASURES--Arthritic symptoms assessed clinically and by using Ritchies' index; blood measurements reflecting inflammatory activity; serum IgG, IgM, and IgA antibody titres; HLA tissue type. RESULTS--No difference was observed concerning duration of arthritis, grade of inflammation, and number of joints affected between patients treated and those not treated with antibiotics. Furthermore, there was no significant difference between the two groups in erythrocyte sedimentation rate and haptoglobin, IgG, and IgA concentrations. All values had returned to normal within three months. No patient developed chronic arthritis, but sustained slight arthralgia occurred in three patients. The HLA-B27 antigen was found in 23 (58%) of the patients, and its presence did not affect clinical outcome. The IgG, IgM, and IgA antibody responses were similar in patients treated with antibiotics and those not treated. CONCLUSION--Short term antibiotic treatment has no beneficial effect on the clinical outcome of reactive arthritis associated with enteric infection.