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Biomedical subjects

A Geissler

Publications and source records attributed to A Geissler.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Masked course of Whipple disease with uveitis, infection, endocardial involvement and abdominal lymphomas--case report and review of the literature].

Whipple's disease is a systemic disease which may virtually affect any organ system, but in many cases it involves the small intestine causing gastrointestinal symptoms. The differential diagnosis is difficult since symptoms may be nonspecific. We report the case of a 44-year old white male patient with a history of migrating arthralgia and chronic fatigue. The patient newly developed an uveitis and underwent a vitrectomy; the further clinical work-up including gastroscopy with intestinal biopsy revealed no sufficient diagnosis. Subsequently, the patient's condition deteriorated with marked weight loss, fever and progressive weakness. An anaerobic sepsis with a corynebacterium was confirmed and with i.v.-antibiotics the patients's condition improved markedly. The further examinations disclosed enlarged mesenteric lymph nodes and the involvement of other organs (endocard, liver). CT-guided biopsy only showed fatty degeneration, but operative adenectomy confirmed Whipple's disease. The patient remained without relapse on long-term antibiotic treatment with doxycycline until today. Obviously, in our case the intestinal biopsies failed to detect Whipple's disease after the successful initiation of antibiotic treatment. In the absence of gastrointestinal findings and with concomitant secondary diseases the definitive diagnosis can be difficult. In addition, the previous uveitis and the endocardial involvement are most interesting.

Abdominal Neoplasms↗
PubMed1995

Noninvasive assessment of renal artery stenosis. A comparison of MR angiography, color Doppler sonography, and intraarterial angiography.

The purpose of this study was to evaluate MR angiography (MRA) and color Doppler sonography as noninvasive screening methods in suspected renovascular hypertension. Fifty-five consecutive patients with arterial hypertension were examined prospectively using high resolution 3-D TOF MRA and color Doppler sonography. Intraarterial angiography was the standard of reference. Stenoses of 60% or more were regarded as significant. MR angiograms were evaluated by 3 independent observers who studied 110 main renal arteries. All 8 significant stenoses and 2 occlusions were correctly classified with MRA while one 60% stenosis was underestimated by color Doppler sonography. Mild stenoses were overestimated by MRA in 4 and by color Doppler sonography in 6 cases. A drawback of both methods was the large number of not evaluable arteries (6 in MRA, 11 in color Doppler sonography). These arteries were regarded as pathologic because stenosis could not be excluded. Due to this fact specificities of MRA and color Doppler sonography were 90% and 85% respectively. Accessory vessels were detected in 47% (8/17) by MRA and in 0% (0/17) by color Doppler sonography.

Adult↗
PubMed1993

Analysis of biophysical differences between oxidized and reduced chloroplast NADP-malate dehydrogenase.

Various properties of purified chloroplast NADP-malate dehydrogenase were analyzed with respect to the redox state of the light/dark-modulated enzyme. The reduced enzyme is less resistant to heat, but the instability can be overcome by the addition of the coenzyme NADPH. Similarly, instability of the reduced NADP-MDH at high pH is alleviated by NADPH. The kinetics and protection characteristics of the alkylation of accessible thiols of NADP-MDH are used to describe the location of essential thiols relative to the active site, since again the coenzyme protects the active enzyme very effectively from inactivation by alkylation. The increased hydrophobicity of the reduced as opposed to the oxidized enzyme becomes apparent as the loss of activity from solutions due to adsorption to plastic surfaces. The kinetics and the solvent dependency of this process are analyzed and discussed, both from the practical (recovery of the purified enzyme) and the physiological point of view (in vivo protein/protein and protein/membrane interactions). The oxidized NADP-MDH has a lower tendency to bind to solid surfaces. NADP(H) efficiently prevents adsorption of the reduced form. Macromolecular solvents (polyethylene glycol), detergents (Triton X-100), or competing proteins also protect this otherwise very hydrophobic form from irreversible loss due to adsorption. Ribulosebisphosphate carboxylase/oxygenase and polyethylene glycol 10,000, however, used as competing substances only keep the oxidized, not the reduced, NADP-MDH in solution.

Chloroplasts↗
PubMed1993

Fatal pneumonia due to Serratia proteamaculans subsp. quinovora.

Serratia proteamaculans subsp. quinovora was isolated from several samples (blood cultures, tracheal aspirates, pleural effusion) from a patient with pneumonia. This is the first clinical isolate and the first documented human infection caused by this organism.

Adult↗
PubMed1992

Real-time study of the urea cycle using 15N n.m.r. in the isolated perfused rat liver.

1. Isolated rat liver was perfused with 10 mM-15NH4Cl, 5 mM-lactate and 1 mM-ornithine, or with 3 mM-[15N]alanine and 1 mM-ornithine, in haemoglobin-free medium. The liver was physiologically stable for over 3 h and synthesized urea at the rate of 1.15 mumol.min-1.g of liver-1 (15NH4(+)-perfused) or 0.41 mumol.min-1.g-1 ([15N]alanine-perfused). 2. The perfused liver was continuously monitored by 15N n.m.r. spectroscopy at 20.27 MHz for 15N. Well-resolved 15N resonances of precursors and intermediates of the urea cycle, present at tissue concentrations of 0.2-3.0 mumol/g, were observed from the intact liver in 5-40 min of acquisition. Key metabolites in liver extract and the final perfusion medium were analysed by n.m.r. and by biochemical assays to determine fractional 15N enrichment and the total 15N recovery. 3. In 15NH4(+)-perfused liver (n = 6), 15N incorporation into glutamate and alanine (1.0-1.3 mumol/g), as well as progressive formation of [15N2]urea, was observed during the first 2 h of perfusion. In the second and third hour, hepatic concentrations of [omega-15N]citrulline and [omega,omega'-15N]argininosuccinate increased to n.m.r.-detectable levels (0.3-0.9 mumol/g). The [15N]aspartate pool was large in the absence of added ornithine, but on its addition was rapidly incorporated into argininosuccinate (n = 3). 4. In [15N]alanine-perfused liver, major metabolites were [15N]glutamate, [gamma-15N]glutamine and [15N]urea. Urea-cycle intermediates were undetectable. 5. The results suggest that, in intact liver provided with excess ammonia, low concentrations of cytosolic argininosuccinate synthetase and argininosuccinate lyase limited the rate of metabolite flux in the urea cycle. By contrast, in alanine-perfused liver at a physiological rate of urea synthesis, mitochondrial carbamoylphosphate synthetase was rate-limiting. 6. The potential utility of 15N n.m.r. for study of metabolite channelling through urea-cycle enzymes in intact liver is discussed.

Alanine↗
PubMed1992

[Gangrene of the perineum. Plea for a standardized therapeutic management apropos of 50 cases].

From 1988 to 1992, 50 cases of perineal gangrene were treated with a therapeutic protocol combining: a) repeated extensive excisions, b) hyperbaric oxygen therapy, even before surgery if this was possible, and c) intensive care. The mortality rate was 24% (12/50). It was even higher in patients admitted more than 6 hours after diagnosis. The average stay in hospital was of 20 (+/- 2) days. Four patients presented with residual signs. Twenty-eight (56%) had had colostomy for lesions originating in the rectum or threatening the anal margin; 9 of these patients died, while gastrointestinal continuity was restored in another 17 cases. There were three predictive factors of survival in this series: a) early diagnosis and treatment, b) severity index on admission, c) some associations of bacteria.

Adult↗
PubMed1992

[Imaging in isolated pulmonary immunocytoma].

A extranodal pulmonary immunocytoma that originated from the lung is reported. It was hidden behind the picture of a mid-lobe syndrome at repeated imaging controls over a 1.5-year period. In the further course a local progression occurred displayed by roentgenography and computer tomography including calcifications within the pulmonary tumor. A newly developing monoclonal gammopathy was detected by immunoelectrophoresis at the same time. Bronchopulmonary symptoms due to the tumor did not exist. After local resection of the lymphoma monoclonal gammopathy disappeared. However, a recurrence of monoclonal gammopathy developed after eight months.

Biopsy↗
PubMed1991

[MR tomography of aneurysmal bone cyst].

The preoperative findings of magnetic resonance imaging (MRI) in six histology-proven aneurysmal bone cysts (ABC) are examined and compared with previous publications concerning MRI of ABC. The signal intensities differ considerably, and not all of our cases conform with the literature data. They can be summarised in three different subheadings: one form that is very inhomogeneous in T1- and T2-weighting, with fluid-fluid levels in the cystic spaces; one intermediate form without fluid-fluid levels, which is inhomogeneous only in T2-weighted images; and finally, an unusual form of ABC that has homogeneous low signal both in T1- and T2-weighting, and which has not been described in literature so far.

Adolescent↗
PubMed1990

[Renal microaneurysms in necrotizing vasculitis--incidence in autopsy and clinical value].

Histological renal sections of 24 autopsied patients were evaluated for ectasias with greater than or equal to 2 mm diameter that corresponded to "microaneurysms" of radiologic nomenclature. Such renal "microaneurysms" of smaller and medium sized arteries were seen in 7/9 patients with periarteritis nodosa, 6/10 patients with secondary vasculitides and 1/5 patients with Wegener's Granulomatosis. Lumen ectasias in acute or subacute lesions of smaller and medium sized arteries were caused by fibrinoid necrosis of the arterial walls. Destruction of intimal elastic fibres and scar tissue within the arterial wall resulted in real aneurysmatic ectasias. Generalised, aggressive, necrotizing vasculitides show the highest frequency of microaneurysms. In that cases angiography can frequently establish the definite diagnosis by demonstration of microaneurysms.

Adult↗
PubMed1990

[Plasma cell granuloma. Report of a case].

The authors report a case of plasma cell granuloma of the lung, an inflammatory tumour occurring in a young Egyptian aged 23 without any history of chest diseases. The patient had had three weeks before his hospital admission light haemoptysis and associated with weight loss. The diagnosis was made on a bronchial biopsy. Thus a diagnosis could be made without recourse to surgery because of the occurrence of bronchial invasion. No aetiological factor was found to explain the pathogenesis of the granuloma.

Adult↗
PubMed1989

Chloroplast glucose-6-phosphate dehydrogenase: Km shift upon light modulation and reduction.

Illumination of intact chloroplasts and treatment of chloroplast stroma with dithiothreitol (DTT) both inactivate glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) to less than 10% apparent activity when assayed under standard conditions. Illumination of intact protoplasts and incubation of leaf extract with DTT inactivate about 25-35% of the total G6PDH activity. In the leaf extract, however, further loss of activity is observed if NADP is absent. Light- and DTT-inactivated chloroplast G6PDH can be reactivated by oxidation with sodium tetrathionate or the thiol oxidant diamide. Chloroplast G6PDH is as sensitive toward reductive enzyme modulation in a stromal extract as are other light/dark modulated enzymes, e.g., NADP-malate dehydrogenase. Also, glutathione, provided it is kept reduced, is sufficient to cause inactivation. Light- and DTT-induced inactivation are shown to be due to a Km shift with respect to glucose-6-phosphate (G6P) from 1 to 35 and 43 mM, respectively, and with respect to NADP from 10 to 50 microM without any significant change of the Vmax. NADPH competitively (NADP) inhibits the enzyme (Ki = 8 microM). Reactivation by oxidation can be explained by an enhanced affinity of the oxidized enzyme toward G6P and NADP. The pH optimum of the reduced enzyme is more in the alkaline region (pH 9-9.5) as compared to that of the oxidized form (pH 8.0). The presence of 30 mM phosphate causes a shift of 0.5 to 1.0 pH unit into the alkaline region for both forms.

Chloroplasts↗
PubMed1987

[Difficulties in the analysis of peritoneographic images].

Peritoneography was performed in 122 patients clinically suspected of hernia without definite palpation findings. 108 cases could be assessed without any doubt (in 40 patients proof of hernia and in 68 patients definite exclusion of hernia). In 14 cases (= 11.5%) the images were difficult to classify. These cases and the variations of normal x-ray anatomy are described.

Hernia, Inguinal↗
PubMed1987

Biochemical monitoring of the lung during and after extracorporeal circulation.

The activity of NAG, lysozyme and PMN-elastase has been investigated in the superior vena caval and left atrium blood collected from patients who underwent open heart surgery. The effect of various types of respiration on the enzyme release has been also documented. Concentration gradients between v. cava sup. and left atrium has been used as an index for pulmonary damage post operatively. We found a time dependent increase of all enzymes during extracorporeal circulation. However, only the release of NAG and lysozyme is characteristic for pulmonary damage. We observed significant higher enzyme release from the lung after Apnea ventilation compared with the PEEP and low frequency ventilation group. Also significant higher NAG and lysozyme activity was found in patients who needed longer respiration post-operatively. PMN-elastase seems to be not suitable for diagnosis of post perfusion lung because the main amount of elastase released by mechanical destroy of the granulocytes.

Acetylglucosaminidase↗