Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 199 records · Page 11Linked to original sources

PubMed1997

Unemployment and cardiovascular diseases: a causal relationship?

Unemployment has become a socio-political problem of great importance in the Western industrialised countries. Although negative effects on social life and psyche resulting from unemployment are regarded as scientifically accepted today, a possible causal relationship between job loss and somatic illnesses is still a matter of controversy. A possible target organ is the cardiovascular system. The aim of this study was therefore to check by means of extensive literature analysis to what extent unemployment can be seen to influence cardiovascular morbidity. Particular attention was paid to the methods used and the clinical relevance of the results. Person-related epidemiological studies published since 1980 which investigated changes in cardiovascular risk factors associated with unemployment or prevalence rates of manifest disease influenced by unemployment were included in the final evaluation. In some cases statistically significant associations were found between unemployment and the increase in cholesterol levels or systolic/diastolic blood pressure, but the clinical relevance of such slight changes is questionable. To consider unemployment as an independent, social, cardiovascular risk factor is at present unwarranted. An increase in the prevalence rates of coronary heart disease or arterial hypertension causally linked in some studies with unemployment is scientifically questionable due to severe methodological shortcomings. On the basis of the currently available methodologically acceptable studies, the question of a quantitative contribution of unemployment to cardiovascular disease cannot be answered conclusively.

Adult↗

PubMed1997

The efficacy of laparoscopic surgery in the diagnosis and treatment of peritonitis. Experience with 107 cases in Mexico City.

BACKGROUND: Peritonitis continues to be an important cause of morbidity and mortality and often an etiologic diagnosis is unclear. To evaluate the efficacy and safety of laparoscopy the authors analyzed their 5-year experience with this modality of treatment. METHODS: A review was made of 107 consecutive nonselected laparoscopic procedures performed between October 1990 and November 1995. The diagnosis was established by clinical, laboratory, and imaging findings and confirmed by laparoscopy and/or laparotomy. RESULTS: An etiologic diagnosis was unclear in 35% of the cases and was established in all by laparoscopy; 94 patients (87.9%) were successfully treated by laparoscopy while 13 (12.1%) required conversion. Mortality was 4.6%; 14% had postoperative complications and 7.4% had reoperations. CONCLUSIONS: Laparoscopic surgery is safe and very efficient in the diagnosis and treatment of patients with peritonitis. In most instances a definitive treatment can be carried out without conversion and has the additional and well-known advantages of minimally invasive surgery.

Abdomen, Acute↗

PubMed1997

Long-term histological follow-up of genetically modified myoblasts grafted into the brain.

Although primary muscle cells have been used as intracerebral vehicles for transgene expression in the past, data concerning their long-term survival after grafting into the brain, and the reaction of the host tissue to their implantation are lacking. In order to study these aspects, we have implanted, into the brain, primary muscle cells infected ex vivo with recombinant retroviruses carrying the E. coli LacZ gene. The muscle cells were delivered stereotaxically into different areas of the brain of adult rats and the grafts were analyzed up to 105 days after implantation. Intraventricular implantations did not lead to surviving grafts. In contrast, myoblasts developed when they were grafted into gray or white matter regions. They appeared numerous during the first weeks, but decreased dramatically in number over time. Over months, the grafts appeared to fill up with collagen. Astrocytes elaborated a continuous glia limitans surrounding the implant. Blood vessels coming from the host tissue were found within the grafts. The blood-brain barrier was permanently disrupted within the transplants. beta-Galactosidase activity was abundant during the first weeks, but decreased to a very low level subsequently. This decrease paralleled that of the number of muscle cells. In conclusion, myoblasts transplanted into the adult brain survived only temporarily, which implies a transient transgene expression. In addition, before being eliminated, muscle cells were surrounded by a glia limitans, which may limit exchanges with the host tissue. Altogether, these results suggest that intracerebral transplantation of myoblasts may possibly provide a relevant vehicle only for short-term delivery of a gene product.

Animals↗

PubMed1997

Diminished adrenal androgen secretion in familial glucocorticoid deficiency implicates a significant role for ACTH in the induction of adrenarche.

OBJECTIVE: The mechanism of adrenarche is controversial, and there have been competing claims that its origin is in the hypothalamo-pituitary axis or in the adrenal gland itself. ACTH is proposed inducer of adrenarche so patients with ACTH resistance due to be familial glucocorticoid deficiency syndrome provide a model to clarify the degree to which ACTH is involved in the regulation of adrenal androgen secretion during adrenarche. DESIGN: Random analysis of plasma adrenal androgens and urinary adrenal androgen output in treated patients with familial glucocorticoid deficiency. PATIENTS: Eleven patients (6 males and 5 females, aged 6.5-21.6 years, 4 prepubertal, minimum bone age 9 years) with familial glucocorticoid deficiency were studied. In 6, mutations, in the coding region of the ACTH receptor are the cause of their ACTH resistance. In the remaining 5 the receptor was normal. MEASUREMENTS: Physical examination, basal serum cortisol, basal plasma ACTH, serum cortisol after stimulation with 250 micrograms ACTH(1-24), plasma dehydroepiandrosterone-sulphate (DHEAS) and plasma androstenedione (A4), total urinary androgen excretion and single-stranded sequencing of the coding region of the ACTH receptor. RESULTS: DHEAS was undetectable in 8, and detectable but below the age-matched reference values in 3 patients. A4 was measured in 10 patients, and in 3 patients (2 in late puberty) was found to be subnormal whereas in the remaining 7 patients A4 was normal for age and pubertal stage consistent with the gonadal contribution to peripheral A4 levels. Significantly diminished output of urinary adrenal androgen metabolites in 3 patients confirmed the results found in serum. The lack of adrenarche was independent of the presence of a mutation within the ACTH receptor and of the severity of glucocorticoid deficiency. Despite adequate glucocorticoid replacement therapy ACTH levels remained elevated in 10 of the 11 patients. CONCLUSIONS: Although reduced adrenocortical inner zone cell number may contribute to the lack of adrenarche, in some patients there appears to be a discrepancy between partial glucocorticoid deficiency and significantly diminished adrenal androgen secretion. These data imply a significant contribution of ACTH to the regulation of adrenarche in normal children either by having a priming effect on the adrenal gland or by acting in concert with other adrenal androgen stimulating factors.

Adolescent↗

PubMed1997

Sensitivity of Entamoeba histolytica and Entamoeba dispar patient isolates to human complement.

Twenty-one Entamoeba histolytica and 56 Entamoeba dispar patient isolates were investigated for their sensitivity to the classical and alternative pathway of human complement, E. histolytica and E. dispar patient isolates were differentiated by polymerase chain reaction and hexokinase isoenzyme typing. It was found that 90.3% (+/- 12.0%) of the trophozoites of E. histolytica were lysed after 30 min by the alternative pathway of complement in the presence of 50% human serum (19 isolates showed lysis rates higher than 80%), whereas E. dispar cells were less susceptible to the alternative pathway as 68.8% (+/- 28.2%) of lysis occurred. However, 23 of the E. dispar isolates were lysed between 100 and 80% (90.9% +/- 9.1%), demonstrating that about half of the tested E. dispar isolates were highly sensitive to complement lysis. Only 11 of the E. dispar isolates were proven to be ¿resistant' to the alternative pathway of complement and were lysed less than 40%. These results are in conflict to earlier publications, describing resistance of E. dispar to complement lysis (Hamelmann et al. 1992, 1993).

Animals↗

PubMed1997

In vitro and in vivo experiences with ureterorenoscope by Gelet.

Using ureterorenoscopes with unidirectional flow, the urologist faces a conflict between a good view on one hand and high pressure in the ureter and the pelvic collecting system of the kidney on the other hand. The ureterorenoscope designed by Gelet, which has continuous (bidirectional) flow and separate irrigation and working channels, was compared with the instrument by Pérez-Castro, which has a common irrigation and working access. The features investigated were optical quality, flow-irrigation characteristics, and handling. The latest generation of ureterorenoscopes provides small total diameters because of minimized working channels and fiberoptic image and light transmission. These semirigid instruments combine the features of flexible endoscopes and traditional ureterorenoscopes. The Gelet instrument offers continuous flow, achieved by separation of the irrigation and working channel, and provides a good view even when working instruments are inserted. The additional outlet channel prevents high pressure in the ureter and renal pelvis and offers another access for instrumentation, if necessary, which means maximum safety for the patient. Because the connection of camera and light source on a flexible system is separated from the instrument, ureterorenoscopy is a more convenient procedure for the urologist.

Fiber Optic Technology↗

PubMed1997

Factors affecting the pharmacokinetics of parenteral chloramphenicol in enteric fever.

Chloramphenicol pharmacokinetics were studied in 29 Nepalese adults diagnosed with uncomplicated enteric fever and randomized to receive succinate ester 30 mg/kg i.v. or i.m. Serial plasma concentrations of chloramphenicol, and iothalamate (to estimate glomerular filtration rate), antipyrine (hepatocellular function) and Indocyanine Green (liver blood flow) were measured by HPLC and kinetic parameters estimated by non-compartmental analysis. In culture-positive patients (n = 16), mean residence times (MRTs) and steady-state volumes of distribution (V(d)ss) for i.v. chloramphenicol (mean +/- S.D.; 4.9 +/- 0.9 h and 1.9 +/- 0.8 L/kg; n = 7) were less than after i.m. chloramphenicol (12.3 +/- 7.3 h and 3.7 +/- 2.5 L/kg; n = 9; P < 0.05), with a higher peak plasma concentration after i.v. (16.2 +/- 9.1 versus 7.8 +/- 3.6 mg/L; P < 0.05); plasma clearance (Cl(p)) was similar in the two groups (368 +/- 172 and 310 +/- 224 mL/kg/min after i.v. and i.m. respectively). In 17 patients examined during convalescence, MRT and Vdss were less than in acute illness regardless of route chloramphenicol administration. There were similar changes in chloramphenicol kinetic parameters in culture-negative patients. Antipyrine Cl(p) and liver blood flow correlated weakly with chloramphenicol Cl(p) in culture-positive patients (P < 0.1) and were higher in convalescence; no such associations were seen for iothalamate Cl(p). These data indicate that i.v. chloramphenicol produces peak plasma concentrations which are on average twice those after i.m. injection of the same dose, due principally to a smaller V(d)ss. Cl(p) is uninfluenced by route of administration and is determined more by hepatic metabolism than renal excretion. Intramuscular treatment may result in sub-therapeutic chloramphenicol concentrations initially, but continued regular i.v. dosing is more likely to produce levels at which bone marrow toxicity occurs.

Adolescent↗

PubMed1997

A new class of plastidic phosphate translocators: a putative link between primary and secondary metabolism by the phosphoenolpyruvate/phosphate antiporter.

We have purified a plastidic phosphate transport protein from maize endosperm membranes and cloned and sequenced the corresponding cDNAs from maize endosperm, maize roots, cauliflower buds, tobacco leaves, and Arabidopsis leaves. All of these cDNAs exhibit high homology to each other but only approximately 30% identity to the known chloroplast triose phosphate/phosphate translocators. The corresponding genes are expressed in both photosynthetically active tissues and in nongreen tissues, although transcripts were more abundant in nongreen tissues. Expression of the coding region in transformed yeast cells and subsequent transport measurements of the purified recombinant translocator showed that the protein mediates transport of inorganic phosphate in exchange with C3 compounds phosphorylated at C-atom 2, particularly phosphoenolpyruvate, which is required inside the plastids for the synthesis of, for example, aromatic amino acids. This plastidic phosphate transporter is thus different in structure and function from the known triose phosphate/phosphate translocator. We propose that plastids contain various phosphate translocators with overlapping substrate specificities to ensure an efficient supply of plastids with a single substrate, even in the presence of other phosphorylated metabolites.

Amino Acid Sequence↗

PubMed1997

Girls with virilisation in childhood: a diagnostic protocol for investigation.

AIM: To analyse critically a protocol for the investigation of girls presenting with virilisation in childhood. METHODS: Twenty five girls aged 1.6-8.7 years with features of virilisation were evaluated. Twenty four had presented with pubic hair, eight with auxilliary hair, seven with facial acne, four with clitoromegaly, and 10 with tall stature. They underwent clinical assessment (height, weight, height velocity, staging of puberty, physical examination for acne, body odour, and clitoromegaly) and laboratory assessment comprising basal concentrations of cortisol, 17 OH-progesterone (17 OHP), androstenedione, dehydroepiandrosteronesulphate (DHEAS), testosterone, and oestradiol. The above steroids were also measured during the short synacthen test (0.25 mg intramuscularly) in 16 subjects and low dose dexamethasone suppression tests (0.5 mg at six hourly intervals over 48 hours). Pelvic ultrasound, computed tomography and magnetic resonance imaging of adrenals were carried out when the biochemical findings suggested that there might be an autonomous source of androgen secretion. RESULTS: Clinical and laboratory assessments differentiated the patients into three diagnostic categories: adrenarche (18 cases), congenital adrenal hyperplasia (five cases), and adrenocortical tumour (two cases). The last had elevated concentrations of DHEAS, 1.5 and 19.1 mumol/l (normal value < 0.5 mumol/l), androstenedione, 24.6 and 21.8 nmol/l (normal < 1 nmol/l), and testosterone, 4.5 and 2.4 nmol/l (normal < 0.8 nmol/l), with none suppressing on dexamethasone suppression. Congenital adrenal hyperplasia subjects had elevated basal serum concentrations of 17 OHP (n = 4): 250, 140, 14, and 14.1 nmol/l (normal < 10 nmol/l) and elevated peak values of 17 OHP after synacthen (n = 3): 76, 179.5, and 175 nmol/l. Adrenarche patients had elevated basal concentrations of DHEAS (median: 2.3 mumol/l; n = 17) and androstenedione (median 2.6 nmol/l; n = 17). Nine patients also had elevated basal serum testosterone concentrations (median 0.9 nmol/l). Peak values of 17 OHP after synacthen were significantly different from baseline (n = 12) and were < 50% of the lowest value in congenital adrenal hyperplasia. Serum DHEAS, androstenedione, and testosterone suppressed following dexamethasone suppression (n = 16), thereby distinguishing adrenarche patients from adrenal tumour patients. Clinical details did not distinguish patients, except for clitoromegaly which was present only in the tumour and congenital adrenal hyperplasia patients. CONCLUSIONS: This protocol proved useful and practical in cases of virilisation presenting particular diagnostic difficulty.

Adrenal Cortex Neoplasms↗

PubMed1997

Angiotensin-converting enzyme genotype and renal allograft survival.

Increased activity of the renin-angiotensin system has been implicated in decreased, long-term survival of renal allografts. Recent studies suggest that a deletion variant of the angiotensin-converting enzyme, associated with increased humoral and tissue activity of this enzyme, is a risk factor for the development of diabetic nephropathy and the progression of IgA nephropathy. To determine whether the deletion variant of the angiotensin-converting enzyme gene influences the long-term outcome in renal transplant recipients, the relationship between donor and recipient angiotensin-converting enzyme genotype and clinical outcome were examined over a follow-up period up to 30 mo in a cohort of 269 Caucasian patients undergoing kidney transplantation between 1988 and 1993. In a subsequent case control study, the frequencies of the angiotensin-converting enzyme genotype were compared in a group of Caucasian patients with a graft survival of less than 3 yr (mean survival, 11 mo; n = 328) with the frequencies in patients with a graft survival of at least 3 yr (mean survival, 65 mo, n = 461). Neither in the cohort nor in the case control study was there a significant effect of recipient or donor angiotensin-converting enzyme genotype on transplant survival. Furthermore, the frequency of the angiotensin-converting enzyme deletion allele both in recipients and donors was similar to that reported in Caucasian controls. This study, therefore, does not support the hypothesis that the recipient or donor angiotensin-converting enzyme insertion/deletion polymorphism is an important determinant of transplant survival in Caucasian patients undergoing renal transplantation.

Adult↗

PubMed1997

Differentiation of Entamoeba histolytica and Entamoeba dispar from German travelers and residents of endemic areas.

Entamoeba histolytica and E. dispar detected in fecal samples of German travelers and residents of tropical and subtropical countries were cultured and differentiated by the polymerase chain reaction (PCR) and hexokinase isoenzyme typing. Twenty-one of 60 isolates were identified as E. histolytica. It was shown that 13 of 18 German short-term travelers were infected with E. histolytica, whereas only three of 22 of the examined inhabitants of tropical countries and five of 20 German long-term travelers harbored E. histolytica. It appears that short-term travelers represent a high risk group for infection with the pathogen E. histolytica.

Animals↗

PubMed1997

Use of subdiaphragmatic bupivacaine instillation to control postoperative pain after laparoscopic surgery.

Although postoperative pain has been reduced significantly since the advent of laparoscopic surgery, many patients still complain of moderate abdominal and shoulder pain during the first 48 to 72 h after surgery. In this study, the effect of subdiaphragmatic instillation of bupivacaine after laparoscopic cholecystectomy was investigated. The evaluation of postoperative pain was done according to a numerical verbal scale and the dose of analgesia required. The results showed a considerable reduction of postoperative pain during the first 48 h after surgery in patients who received bupivacaine instillation. Although the literature shows certain controversy as to the effects of similar methods, our study concludes that instillation of a long-acting anesthetic, such as bupivacaine, into the subdiaphragmatic space after laparoscopic procedures is effective in postoperative pain reduction.

Adult↗

PubMed1997

[Social medicine evaluation of pre-employment medical screening of civil service candidates].

The findings and resulting number of rejections from 9.043 medical examinations of candidates for posts as civil servants in 1994 in Bavaria and a retrospective evaluation of 500 examinations at two large public health departments in Bavaria were used to discuss the value of such examinations and present possible alternatives. The rate of rejections for medical reasons in the 9.043 examinations of civil servants starting new jobs in Bavaria was 0.57%. The most frequent reason for rejection was obesity. In the retrospective evaluation of 500 medical examinations of candidates starting new jobs there were no cases of final rejection for medical reasons. In 0.4% of cases (n = 2) the candidates were considered suitable for the probationary period before becoming a civil servant, but unsuitable for health reasons for a life-time post in the civil service. In 27% of cases the findings were normal without any diagnosis stated in the examination report. The most frequent diagnoses were refractive ametropia (55.8%) and changes in the locomotor system (22.2%), in particular deviation of the axis are vertebral column (17.6%). The results are comparable with those obtained in studies carried out in Europe, although the procedures and study designs differed. Even with a low number of rejections of around 0.5%, examinations of the candidates economically justified for the employer (the state). In view of the high number of civil servants taking early retirement, the sensitivity and specificity of the medical examinations before starting work are discussed, as well as possible and better alternatives to a single examination. One suggestion is continuous monitoring of all civil servants by a physician specialised in occupational medicine, although in particular for teachers and office workers no standards have been developed for the scope and frequency of occupational-medical health checks and consultation.

Adolescent↗

PubMed1997

[Present problems in detection of sources of infection and chains of infection with enterohemorrhagic E. coli (EHEC)].

In the context of the detection of the haemolyticuraemic syndrome (HUS) and of enterohaemorrhagic E. coli (EHEC) in 13 persons, 372 faeces samples from 13 herds of cattle in northern Bavaria were examined for the presence of EHEC. 128 (34.4%) of the faeces samples were found to be VT-positive. From 78 of these samples (61%), verotoxin-producing E. coli strains (VTEC) could be isolated. During these examinations, E. coli strains with combinations of markers (VT, eae A, EHEC haemolysin) being typical of EHEC were found in 3 samples from animals belonging to the same herd. In 2 cases, these could be assigned to O157:H-, in one, to O118:H16. It has not been possible to detect possible sources of infection and chains of infection assumed to exist in association with the detection of HUS and EHEC infections in humans because most cases had been diagnosed on the basis of verotoxin detection in stool specimens. Moreover, corresponding isolates for a comparative onward differentiation from verotoxin-producing E. coli isolates from animals were not or could not be made available.

Animals↗

PubMed1997

[Medical rehabilitation between politics and demographic development--consequences for quality management in rehabilitation clinics].

Drastic changes are ahead for medical rehabilitation in the wake of austreity measures in the pension insurance domain. This paper presents consequences for rehabilitation hospitals and their current strategies of coping in the German health care system. Quality management now needs long and medium term planning, rather than short-term reactions. Demographic trends and a changing spectrum of morbidity indicate possible survival strategies. These societal developments are already incorporated in Total Quality Management.

Chronic Disease↗

PubMed1997

Restoring function and esthetics in a patient with amelogenesis imperfecta.

Amelogenesis imperfecta is a rare dental disease and presents a major challenge to the dentist. With the tremendous advances in the field of esthetic dentistry, especially in bonding to dentin, it is today possible to restore function and esthetics to an acceptable level. The need for full crown preparation has been decreased to an absolute minimum. A case of amelogenesis imperfecta, complicated by a malocclusion, is presented. A combination of periodontal treatment and resin-bonded porcelain onlays and nobel alloys resulted in a highly successful outcome. The virtual absence of enamel was overcome with the aid of dentin bonding.

Adult↗

PubMed1996

Semirigid instrumentation in the management of lumbar spinal conditions combined with circumferential fusion. A multicenter study.

STUDY DESIGN: Patients with the diagnosis of degenerative disc conditions or spondylolisthesis undergoing circumferential fusion with posterior pedicle screw fixation using a semirigid rod were reviewed. OBJECTIVES: To determine the effectiveness of this approach in achieving a spinal fusion and satisfactory clinical outcome, and to determine the complications associated with the procedure. SUMMARY OF BACKGROUND DATA: The use of instrumentation to stabilize the lumbar motion segments and thereby enhance the fusion rate has been proposed in a number of studies. Semirigid fixation was believed to be effective in achieving these objectives without concern for stress-shielding, which was suggested by some authors using rigid fixation systems. METHODS: Patients who required spinal fusion with anterior and posterior approaches because of specific lumbar pathology or previous surgeries were selected. The surgery consisted of an anterior interbody fusion using allograft, followed by a posterolateral fusion and pedicle screw fixation. Fusion was determined by continuity of trabecular bridging, and outcomes were determined by pain reduction and return to previous levels of activity. Fusion was considered solid if the two posterolateral areas were fused (Zones one and two), if the anterior interbody area was fused (Zone three), or if all three zones were fused. Complications were documented during and after surgery. RESULTS: Sixty-two percent of patients had previous surgery with 25% of these patients having a diagnosis of pseudarthrosis. Fifty-five percent of patients had two or more levels fused, and 43% were heavy smokers. Ninety-seven percent of patients had successful fusions. Pain was significantly reduced on a pain analogue scale from 7.1 to 2.1 in the back and from 5.8 to 1.5 in the leg (p < 0.006 and 0.0001, respectively). Fifty-nine percent of patients returned to their previous level of activity, and 18% returned to lighter work or job retraining, for a total of 77% returning to the same or lighter levels of activity. Complications included metal failure, 4.9%; neurologic deficit, 1.2%; deep infection, 1.2%; deep venous thrombosis, 4.9%; and vascular injury, 2.4%. Fatal pulmonary embolus occurred in one patient. CONCLUSION: This technique produces a satisfactory fusion rate (97%) and a good clinical outcome based on pain reduction and return to a satisfactory level of activity (77%). It is associated with few, but significant, complications that compare well with other reported series in a difficult group of patients. This procedure should be reserved for patients who are considered to be at high risk for not achieving spinal fusion.

Adolescent↗

PubMed1996

Hepatocyte growth factor expressed by a retrovirus-producing cell line enhances retroviral transduction of primary hepatocytes: implications for in vivo gene transfer.

Hepatocyte Growth Factor (HGF) is the more potent mitogen of mature hepatocytes. We have examined the effect of human HGF expression by a recombinant retroviral cell line (MFG-LacZ) on retroviral transduction of primary mouse and human hepatocytes. The HGF in the supernatant of MFG-LacZ cell line was correctly processed and biologically active. Transduction of mouse and human hepatocytes with the supernatant of transfected cells was increased 5-fold, as determined by beta-galactosidase activity. The production of HGF was stable and did not interfere with the viral titers of the producer cells. This study provides evidence that expression of HGF within a retrovirus-producer cell line increases the transduction rate of primary hepatocytes. Since the number of corrected cells is a limiting step for phenotypic correction of liver deficiencies, our approach should improve hepatic gene therapy efficiency. Furthermore this cell line should be useful for in vivo liver gene therapy.

Animals↗