Search PubMed⌕ Search

Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 217 records · Page 12Linked to original sources
PubMed1996

[MALT-type low-grade B-cell lymphomas of the stomach and Helicobacter pylori].

From January 1 1994 to March 1 1995 we observed 6 patients with gastric low-grade B-cell lymphoma of MALT type in association with Helicobacter pylori infection. Endoscopically only 3 of the 6 patients presented with pathological findings. All but one patient with metastatic carcinoma received antibiotic therapy for Helicobacter pylori. Follow-up was not possible in one patient who died unexpectedly. In all 4 patients followed-up, eradication of Helicobacter pylori resulted in regression of the malignant lymphoma. During the median follow-up time of 7 months (2-13 months) no relapse of lymphoma was observed. Our results confirm that gastric low-grade B-cell lymphoma of MALT type can regress after eradication of Helicobacter pylori.

Adult↗
PubMed1996

The lipocalin Xlcpl1 expressed in the neural plate of Xenopus laevis embryos is a secreted retinaldehyde binding protein.

The cellular and structural properties and binding capabilities of a lipocalin expressed in the early neural plate of Xenopus laevis embryos and the adult choroid plexus have been investigated. It was found that this lipocalin, termed Xlcpl1, binds retinal at a nanomolar concentration, retinoic acid in the micromolar range, but does not show binding to retinol. Furthermore, this protein also binds D/L thyroxine. The Xlcpl1 cDNA was expressed in cell culture using the vaccinia virus expression system. In AtT20 cells, Xlcpl1 was secreted via the constitutive secretory pathway. We therefore assume that cpl1 binds retinaldehyde during the transport through the compartments of the secretory pathway that are considered to be the storage compartments of retinoids. Therefore, cpl1-expressing cells will secrete the precursors of active retinoids such as retinoic acid isomers. These retinoids may enter the cytosol by diffusion or receptor-controlled mechanisms, as has been shown for exogenously applied retinoids. Based on these data, it is suggested that cpl1 is an integral member of the retinoid signaling pathway and, therefore, it plays a key role in pattern formation in early embryonic development.

Amino Acid Sequence↗
PubMed1996

Magnetic resonance imaging of adrenocortical adenomas in childhood: correlation with computed tomography and ultrasound.

There are few descriptions of the magnetic resonance (MR) appearance of hyperfunctioning adrenocortical tumours, particularly those occurring in childhood. We studied five patients, two girls and three boys, aged 6-14.3 years, presenting with clinical syndromes of adrenocortical hyperfunction. The diagnoses were Cushing's syndrome (n = 2), virilisation (n = 2), and Conn's syndrome (n = 1). Biochemical features suggested an adrenal lesion in each case. MR and ultrasound were performed in all five cases, with CT in four. Each patient had a functional adrenal tumour secreting either cortisol, androgens or aldosterone alone, or a combination of cortisol, androgens and oestradiol. The histological diagnosis was adenoma in four cases and tumour of indeterminate nature in one case. MR clearly showed the tumours (diameter 1.0-7.5 cm), all the lesions being of high signal intensity relative to liver on T2-weighted sequences. CT revealed an adrenal mass in each of the four patients scanned, three of which enhanced after intravenous contrast medium injection. The multiplanar imaging of MR allowed better distinction from adjacent structures and also demonstrated an unenlarged contralateral adrenal gland. In the patient with a 1-cm Conn's adenoma the lesion was more easily seen on MR than CT. Ultrasound showed the four larger tumours but was unable to visualise the contralateral adrenal or the Conn's adenoma. In conclusion, the MR appearances of four adrenocortical adenomas and one indeterminate tumour in children are described. MR has been found to be at least equal to CT in the detection of these tumours, with some possible advantages. Both techniques are superior to ultrasound.

Adenoma↗
PubMed1996

Large vessel vasculitis without temporal artery involvement: isolated form of giant cell arteritis?

Diffuse arterial involvement in giant cell arteritis (GCA) is well recognized. By contrast, GCA clinically isolated to large vessels without cephalic, rheumatologic or systemic symptoms represents a much rarer manifestation of the disease. We report the cases of 4 elderly women presenting with a diffuse and symptomatic occlusive disease without the typical signs of temporal arteritis, in whom biological, angiographic or pathological findings were suggestive of GCA. Medium to high dose oral corticosteroids were given to the 4 patients, in combination with various revascularization procedures, allowing a fair clinical response. Large vessel arteritis should be considered in elderly women with diffuse non-atherosclerotic occlusive disease and elevated erythrocyte sedimentation rate, even if typical features of GCA are lacking. In those cases, a long-term treatment with corticosteroids is mandatory, but surgical or angioplastic revascularization is often required.

Aged↗
PubMed1996

Can grapefruit juice influence ethinylestradiol bioavailability?

The effects of grapefruit juice on the bioavailability of 17 alpha-ethinylestradiol (EE2) after a single oral administration of 50 micrograms EE2 have been investigated. The pharmacokinetics of EE2 were studied in an open, randomized, cross-over study in which 13 healthy volunteers were administered the drug with herbal tea or grapefruit juice (naringin, 887 mg/ml). In contrast to herbal tea, grapefruit juice increased the peak plasma concentration (Cmax) significantly to 137% (mean; range 64% to 214%, p = 0.0088) and increased the area under plasma concentration-time curve from 0 to 8 hours (AUC0-8) to 128% (mean; range 81% to 180%, p = 0.0186). This study shows that grapefruit juice increases the bioavailable amount of EE2. A possible explanation may be that grapefruit juice inhibits the metabolic degradation of EE2. Whether the increased bioavailability of EE2 following grapefruit juice administration is of clinical importance should be investigated in long-term studies.

Administration, Oral↗
PubMed1996

Rotoresect: new technique for resection of the prostate: experimental phase.

We developed a new resection device-the Rotoresect -with the aim of reducing morbidity during transurethral resection of the prostate (TURP). During rotoresection, a rotating ablator electrode enables simultaneous tissue coagulation by high-frequency current and mechanical tissue ablation. The tissue ablation rate and the extent of bleeding were quantified ex vivo using a blood-perfused porcine kidney (N = 30) and then compared with loop resection and electrovaporization (grooved roller/Rollerball). Additionally, transurethral rotoresection of the prostate and open partial resection of the liver were carried out in five dogs. With the blood-perfused porcine kidney, we demonstrated that the tissue ablation rate increases with increasing of the coagulation current and rotation speed of the ablator electrode. The Rotoresect achieved a tissue ablation rate comparable to that of the resection loop (5.5-6.0 g/min), which was more than twice the rate achieved by electrovaporization (1.7-2.0 g/min). The extent of bleeding during standard loop resection was many times higher (16.5-18.0 g/min) than that induced by rotoresection and electrovaporization (< 2.3 g/min). In our in vivo canine trials, we performed transurethral prostate resection and open segmental liver resection with minimal bleeding. The Rotoresect is a promising instrument for ablation of parenchymal organs during transurethral, laparoscopic, and open surgical procedures.

Animals↗
PubMed1996

Linkage of the gene for the triple A syndrome to chromosome 12q13 near the type II keratin gene cluster.

The triple A or Allgrove's syndrome (MIM*231550) is an autosomal recessive disease characterized by the triad of adrenocorticotropic hormone (ACTH) resistant adrenal insufficiency, achalasia and alacrima. Since its first description by Allgrove et al. (1978) more than 70 cases from all over the world have been reported. The syndrome manifests itself during the first decade of life with severe hypoglycaemic episodes which can cause sudden death. The frequent association with neurological disorders presenting as a mixed pattern of upper and lower motor neuropathy, sensory impairment, autonomic neuropathy and mental retardation may result in a severely disabling disease. As an additional feature some patients have hyperkeratosis of their palms and soles. We have performed a systematic genome linkage scan in eight triple A families of which three were consanguineous [including the large highly inbred kindred described by Moore et al. (1991)]. We obtained conclusive evidence for linkage of the triple A syndrome locus to markers on chromosome 12q13 (D12S368, theta max = 0, Zmax = 10.81) with no indication of genetic heterogeneity. Haplotype and multipoint analyses suggest that the gene is located on a chromosomal segment flanked by the markers D12S1629 and D12S312 which are 6 cM apart. This region harbors the type II keratin gene cluster, and potential candidate genes include SCN8A and HOXC genes.

Adrenal Insufficiency↗
PubMed1996

Effect of jet ventilation on heart failure: decreased afterload but negative response in left ventricular end-systolic pressure-volume function.

OBJECTIVE: To examine the mechanism of cardiac assist with systolic jet ventilation, specifically effects on loading conditions and left ventricular pressure-volume function. Both systolic and diastolic jet ventilation were compared in the absence and presence of heart failure. DESIGN: Prospective, two-factor, repeated-measures study. SETTING: Animal laboratory. SUBJECTS: Ten anesthetized, closed-chest dogs. INTERVENTIONS: The measurement protocol consisted of two phases: a) apnea, randomized jet ventilation (systole- and diastole-synchronized); b) postjet ventilation apnea, before and after heart failure, induced with a propranolol-imipramine-plasma expansion treatment. MEASUREMENT AND MAIN RESULTS: Systolic and diastolic jet ventilation was associated with mean airway pressures of approximately 7 mm Hg and intrapleural pressures of approximately 3 mm Hg in both heart conditions. In normal hearts, jet ventilation (either mode) decreased transmural left ventricular end-diastolic pressure by 40% to 60% (p < .05), left ventricular end-diastolic volume 25 +/- 8%, and stroke volume by 28% to 30%. Heart failure was associated with decreases (41 +/- 6%) in end-systolic pressure-volume function (i.e., pressure change/volume change or elastance), transmural left ventricular end-systolic pressure (22 +/- 3%), and stroke volume (16 +/- 4%), and increased transmural left ventricular end-diastolic pressure (139 +/- 6%). Application of jet ventilation (either mode) during heart failure did not affect stroke volume but significantly (p < .05) attenuated transmural left ventricular end-diastolic pressure by 30% to 40%, left ventricular end-diastolic volumes by 33 +/- 9%, and transmural left ventricular end-systolic pressure by 11% to 19% (p < .05). After jet ventilation, left ventricular elastance was decreased 36 +/- 8% in normal hearts and 35 +/- 11% in failing hearts. Stroke volume, however, returned to baseline levels because of increases in transmural left ventricular end-diastolic pressure in both heart conditions, and also in failing hearts, because transmural left ventricular end-systolic pressure remained decreased approximately 30% (p < .05). CONCLUSIONS: Jet ventilation did not decrease stroke volume in failing hearts because of the afterload-reducing benefit (decreased transmural left ventricular end-systolic pressure) of increased intrapleural pressure in dilated ventricles. Moreover, jet ventilation did not have positive effects on myocardial function and had negative effects on left ventricular elastance in the postjet ventilation period in both normal and failing hearts. Cardiac assist by jet ventilation was not cycle specific, suggesting no selective benefit of jet ventilation over conventional positive-pressure ventilation during heart failure. These studies demonstrate a negative inotropy associated with jet ventilation that, during heart failure, may compromise the general benefit of positive-pressure-mediated increases in intrapleural pressure.

Adrenergic Uptake Inhibitors↗
PubMed1996

Hyperlipaemia intensifies the course of acute oedematous and acute necrotising pancreatitis in the rat.

BACKGROUND: Serum triglyceride concentrations higher than 10 to 20 mmol/l are probably a risk factor for developing acute pancreatitis in humans. AIMS: To therefore analyse the influence of hyperlipaemia on the course of acute oedematous and acute necrotising pancreatitis in rats. SUBJECTS: Male Wistar rats were used in all experiments. METHODS: Six different groups of animals were used: two groups without pancreatitis (controls), two with acute oedematous pancreatitis, and two with acute necrotising pancreatitis. One group from each pair was treated with Triton WR 1339, which induces endogenous hyperlipaemia. Blood samples were taken from all subjects to measure triglyceride, cholesterol, amylase, and lipase. Pancreatic tissue samples were taken and the degree of pancreatic damage was judged microscopically. RESULTS: In the control groups no significant changes occurred, either in serum enzyme activities or in histology. The hyperlipaemic subgroup of animals with acute oedematous pancreatitis developed significantly higher (p < 0.001) serum amylase activities and a greater degree of histological damage (p < 0.01) than the animals of the non-hyperlipaemic acute oedematous pancreatitis group. In the animals with necrotising pancreatitis, serum lipase activity and the histological degree of pancreatic damage were significantly higher in the hyperlipaemic animals than in the non-hyperlipaemic animals. CONCLUSION: This study shows that hyperlipaemia intensifies the course of acute oedematous and acute necrotising pancreatitis in rats.

Acute Disease↗
PubMed1996

Lung mechanics and pulmonary but not systemic vascular responses to ET-1 are Tx and infusion rate dependent.

The role of cyclooxygenase metabolites formation in the systemic and pulmonary vascular and airway responses to different intravenous infusion rates of endothelin-1 (ET-1) was investigated in eight barbiturate-anesthetized mechanically ventilated adult sheep. ET-1 (20, 200, and 400 pmol/kg) was infused into the femoral vein over either 1, 10, or 180 s before and after pretreatment with indomethacin (1.5 mg/kg i.v.). ET-1 infusion produced a dose-dependent systemic vasoconstriction that was similar with all three infusion rates. In contrast, the pulmonary vascular and airways responses to ET-1 were not only dose dependent but also infusion rate dependent so that consistent effects on the pulmonary vasculature and airways were observed only when the peptide was injected over 1 s. At the highest dosage and at the fastest rate of administration, ET-1 produced a fivefold rise in pulmonary vascular resistance, a twofold rise in airway resistance, and a 45% decrease in dynamic pulmonary compliance, whereas no changes were observed when the peptide was injected over 180 s. Plasma levels of 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) increased 20-fold when ET-1 was administered over 1 s but only 5-fold when it was administered over 180 s. Thromboxane B2 (TxB2) increased 5-fold when ET-1 was administered over 1 s and did not increase when ET-1 was given over 180 s. Plasma TxB2 levels were linearly correlated with pulmonary vascular or airway resistance during the bolus ET-1 infusion. Pretreatment with indomethacin completely prevented the ET-1-induced rise in TxB2 and 6-keto-PGF1 alpha and blocked pulmonary vaso- and bronchoconstriction observed, whereas it enhanced systemic vasoconstriction. These results demonstrate that in adult sheep intravenous ET-1 produces pulmonary vaso- and bronchoconstriction that is infusion rate dependent and is associated with the rate-dependent production of thromboxane. In contrast, the increase in systemic vascular tone elicited by ET-1 is not affected by its rate of infusion and does not depend on the secondary generation of cyclooxygenase metabolites.

Animals↗
PubMed1996

New methods of searching for medical literature: comparison of two systems, implementation and user reactions in a urologic department.

Knowledge Finder is the first Medline retrieval system based on CD-ROM technology that allows natural-language queries and accounts for deviations in spelling and terminology. Retrieved citations are ranked in accordance with their possible relevance (fuzzy logic algorithms), thus resulting in speedy orientation on a topic of interest. EasyOrder is an additional software module that enables the user to place an automatic electronic order at the library of choice, via modem, to receive a copy of a full-text article by mail or facsimile. We performed a study comparing search results and times when using a Boolean versus a fuzzy system. This article describes the underlying new concepts, implementation in a urologic department and user reactions to the new possibilities.

CD-ROM↗
PubMed1996

Development and status of social medicine in Germany.

The current status of scientific social medicine in the Federal Republic of Germany is presented against the background of historical development. Ideas differ when it comes to identity, academic institutionalisation, the main emphasis of work, the syllabus and future tasks. The heterogenic diversity of the subject is emphasised by the lack of any generally accepted definition. There is a current tendency to regard social medicine exclusively as population medicine rather than more generally as the interaction between disease/health, general social system and the individual. Clinical practical social medicine, epidemiology, health system research/health economy, and public health can be distinguished as important occupational fields. Acquiring the additional title in social medicine is widely recognised as the necessary further training. However, the discussion about improving the training in social medicine at German universities is still causing much controversy. Secure anchoring within the canon of medical subjects is of particular importance regarding the totality of the subject and its future in medical faculties.

Germany↗
PubMed1996

[Ring trials in expert assessment--a practicable procedure for quality assurance?].

An intercomparison programme for expert assessment was carried out as part of quality assurance for the public health departments in Bavaria. A file documenting medical diagnoses and reports of a patient was presented to medical doctors in a district of Bavaria and in the Academy for Public Health Services in Munich for assessment. The participation was voluntary and anonymous. The case presented was an obese man who wanted to become a civil servant. The doctors were asked to give an expert assessment of his health. Four criteria were used to evaluate the assessments: the assessment, its conclusiveness, the documentation and the epicrisis. 54 out of 100 doctors asked participated. On average all criteria were adequately fulfilled. This paper discusses the advantages and disadvantages of an intercomparison programme for expert assessments in the field of social medicine. Our results show that an intercomparison programme for expert assessments could form part of quality assurance.

Adult↗
PubMed1996

Uric acid lowering effect of oxipurinol sodium in hyperuricemic patients - therapeutic equivalence to allopurinol.

OBJECTIVE: Oxipurinol has been shown to be sufficiently absorbed after oral administration as a rapid release preparation of oxipurinol sodium. We compared the uric acid lowering affect of allopurinol and oxipurinol. METHODS: In a multicenter, randomized, double blind crossover trial in 99 hyperuricemic patients with normal renal function we investigated the uric acid lowering effect of oxipurinol sodium (O) in daily amounts equimolar to 300 mg allopurinol (A). Mean pretreatment plasma uric acid concentrations in groups A/O and O/A were 8.3 +/- 1.4 and 8.7 + /- 1.4 mg/dl, respectively. RESULTS: In group A/O the mean plasma uric acid decreased to 5.4 +/- 1.2 mg/dl with allopurinol treatment, and increased slightly to 5.7 + /- 1.3 mg/dl during the consecutive oxipurinol period. In group O/A plasma uric acid declined to 6.0 +/- 1.4 mg/dl with oxipurinol and was 5.6 + /- 1.3 mg/dl at the end of the allopurinol period. The overall average reduction compared to baseline was 3.0 mg/dl with allopurinol and 2.6 mg/dl with oxipurinol. The difference between the 2 treatments was small but significant (multiple p=0.027,2 tailed). The corresponding mean plasma oxipurinol concentrations were 9.24 mu g/dl at the end of the allopurinol period and 9.9 mu g/dl after treatment with oxipurinol (NS). CONCLUSION: Oxipurinol is well absorbed and sufficiently effective in hyperuricemic patients when administered as a rapid release preparation of oxipurinol sodium. Oxipurinol sodium could be a substitute for allopurinol in hyperuricemic patients and possibly also with new uses for allopurinol.

Adult↗
PubMed1996

Angiotensinogen-M235T genotype and post-transplant hypertension.

BACKGROUND: The angiotensinogen gene has been linked to the development of essential hypertension, and a M235T variant of this gene, associated with increased plasma levels of angiotensinogen, is more common in hypertensives than in normotensive controls in various populations. The present study was conducted to examine whether the M235T variant of the angiotensinogen gene may be a risk factor for the development of hypertension in patients undergoing renal transplantation. METHODS: DNA for genetic analysis was prospectively collected from 269 consecutive patients undergoing kidney transplantation between 1988 and 1993 and their corresponding donors. Presence of hypertension and graft survival was analysed by blinded review of all case records over a follow-up period up to 30 months. Angiotensinogen genotype was determined by a mutagenically separated allele-specific polymerase-chain-reaction technique. RESULTS: While post-transplant hypertension was present in 78% of all patients, no relationship was found between either donor or recipient genotype and the presence or severity of post-transplant hypertension. Furthermore, there was no relationship between angio-tensinogen genotype and graft survival during the course of the study. CONCLUSIONS: These findings do not support the hypothesis that the M235T variant of the angiotensinogen gene is a risk factor for the development of post-transplant hypertension.

Adult↗
PubMed1996

[Social medicine for general practice--initial evaluation of a practice relevant teaching concept].

The form and contents of lectures in social medicine as part of medical studies have caused controversy for some time. In the winter term of 1992/93 a new concept of main lectures in social medicine oriented to medical practice was introduced at the Friedrich-Alexander University of Erlangen-Nuremberg. In particular, these lectures deal with primary medical topics relevant to social medicine, interspersed with case examples, visits to patients and excursions. As a means for students to express critism of the lectures offered, at the end of the summer term of 1994 an evaluation of university tuition was first carried out using an anonymous, standardised questionnaire. Fifty-five of the 179 students registered for the lecture, studying in terms 7 to 12, took part in the survey. Among the regular lecture-goers there was a high acceptance of the concept and presentation of the lecture contents in 75% of those asked. This was not found to be dependent on sex or on how far the students had progressed in their studies. Despite interest in social medicine in 80% of cases, for the vast majority of those asked the subject does not yet play any role as a future field of research or occupation. While 60% of the participants in the questionnaire accorded sociomedical topics an important rank in the study of human medicine, 35% regarded an independent chair for social medicine, against the background of over-full timetables, as unnecessary. On the other hand, the practical relevance and usefulness of what is taught was regarded by 72% as high. Despite a general lack of enthusiasm for lectures the practically-oriented approach has obviously succeeded in making clear to the students the importance of sociomedical topics in routine medical practice.

Adult↗