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Biomedical subjects

G Herrmann

Publications and source records attributed to G Herrmann.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Inferior vena cava compression syndrome in cystic kidney. Duplex ultrasonic diagnosis].

Four months after renal transplantation for polycystic renal degeneration a 38-year-old man developed breathing-related pain in the left upper lung and a sinus tachycardia (130/min). Lung perfusion scintigraphy demonstrated pulmonary emboli from an acute venous thrombosis of the left lower leg. Polycythaemia and impairment of clot-inhibiting factors were excluded. Ultrasound examination of the abdomen revealed stenosis of the inferior vena cava (IVC) distal to the hepatic veins, dorsal to the liver and ventral of a huge right polycystic kidney which had been left in situ at the time of the renal transplantation. Duplex sonography demonstrated a band-like flow profile in the region of the stenosis. Blood flow was clearly increased (0.62 m/s) and not affected by either heart rate or breathing movements. The findings were confirmed by angiography. The right kidney, weighing 5 kg, was removed at surgery. The IVC stenosis was postoperatively found to be relieved and duplex sonography gave normal findings.

Adult↗
PubMed1991

Functional significance of sequences following the TATA box of an immunoglobulin promoter studied by random mutagenesis.

We have investigated the importance of sequences downstream to the TATA box of an immunoglobulin promoter by transfection and in vitro transcription assays. A sequence from -11 to +10 with respect to the transcriptional start site was synthesised by a procedure allowing for random misincorporation of nucleotides. The pool of mutant oligonucleotides was cloned into the respective position of a vector carrying a fusion of a synthetic immunoglobulin heavy chain promoter with the human growth hormone gene. From 200 clones sequenced, 115 were mutants with at least one nucleotide exchange in every position. Whereas most mutations are of minor functional importance, changes at or near the transcriptional start site reduce the promoter activity considerably.

Base Sequence↗
PubMed1991

Evidence for multiple xenogenous origins of plastids: comparison of psbA-genes with a xanthophyte sequence.

When only plastidic features are considered, it is difficult to distinguish between monophyletic and polyphyletic xenogenous origins of plastids. We suggest that a direct comparison of nuclear and plastidic sequence-similarity pattern will help to solve this problem. The D1 amino acid sequence of six major groups of photosynthetic eukaryotes and of the two groups of photosynthetic prokaryotes are now available, including the psbA-gene product from Bumilleriopsis filiformis, which is the first molecular sequence reported for a xanthophycean alga. Evidence is provided for an independent and polyphyletic origin of plastids from five out of the six major taxa of photosynthetic eukaryotes. This conclusion is reached by comparing a plastid-based pattern of D1 similarity with a nucleus-based similarity pattern published recently. Furthermore, the availability of D1 sequences from five eukaryotic algae led to a re-evaluation of the taxonomic position of Prochlorothrix.

Amino Acid Sequence↗
PubMed1991

The effects of pretreatment with nitroglycerin on ischemic left ventricular dysfunction during coronary angioplasty.

To evaluate the degree to which nitroglycerin reduces myocardial ischemia and dysfunction induced by transient coronary occlusion, 19 patients were studied during coronary angioplasty of the left anterior descending coronary artery. After a control occlusion of 60 seconds, 0.2 mg nitroglycerin was administered intravenously and the occlusion was repeated for 60 seconds. Before and during the occlusion period, pulmonary capillary wedge pressure was measured, the intracoronary ECG was recorded, and ventricular volumes, ejection fraction, and regional systolic shortening were obtained by digital subtraction angiography. Nitroglycerin caused a significant fall in pulmonary capillary wedge pressure before (10 vs. 7 mmHg) and at 60 seconds occlusion (18 vs. 14 mmHg), but did not significantly delay the rise in wedge pressure (37 vs. 44 seconds). End-systolic left ventricular volume at 60 seconds of occlusion was reduced by nitroglycerin (77 vs. 68 ml), whereas regional shortening of the ischemic segments remained unchanged (22 vs. 23%). Nitroglycerin did not delay the onset of ischemic ST-segment elevation (14 vs. 14 seconds) and had no effect on the changes of ST elevation in the intracoronary ECG (1.9 vs. 1.9 mV). These findings suggest that intravenous nitroglycerin reduces filling pressure and slightly improves left ventricular global function during acute coronary occlusion. Nitroglycerin, however, has little effect on ischemia-induced regional dysfunction and on ST-segment elevation in the intracoronary ECG.

Adult↗
PubMed1991

[Dose and time dependence of hemodynamic tolerance development during intravenous nitrate therapy in acute myocardial infarct].

Intravenous nitroglycerin therapy during acute myocardial infarction has beneficial effects on infarct size, infarct complications, and mortality. Numerous dosage formulas for the continuous administration of nitrates are currently used, although several studies have demonstrated the rapid development of tolerance during long-term treatment in patients with ischemic heart disease. The dose and dosage of a continuous nitrate application in the clinical setting of acute myocardial infarction has thus yet to be resolved. This study investigated the hemodynamic effects of a 60-h, low- (33 micrograms/min) vs high- (133 micrograms/min) dose intravenous nitroglycerin (NTG) infusion in 16 patients with uncomplicated acute myocardial infarction. In group I (33 micrograms/min NTG; n = 8) the initial nitrate effect on the pulmonary capillary pressure (PCP-control: 14 +/- 1.5; 4 h: 7 +/- 0.9; 60 h: 7 +/- 0.8; mean +/- SEM; all values in mm Hg) and mean pulmonary artery pressure (PAPM-control: 23 +/- 2.3; 4 h: 15 +/- 1.3; 60 h: 14 +/- 1.3) remained unchanged for 60 h. In group II (133 micrograms/min NTG; n = 8) an almost complete loss of the initial effect on PCP (control: 15 +/- 1.6; 4 h: 5 +/- 1.4; 60 h: 12 +/- 1.3) and PAPM (control: 25 +/- 2.0; 4 h: 14 +/- 1.8; 60 h: 20 +/- 1.3) was observed. In contrast to high-dose application the low-dose NTG-infusion induced comparable acute hemodynamic effects that were not attenuated by tolerance development.

Aged↗
PubMed1991

[Experiences with the application of monoclonal Indium-111 antimyosin scintigraphy in the diagnosis of rejection episodes following orthotopic heart transplantation].

Indium-111-labeled Fab fragment imaging using a murine antimyosin monoclonal antibody (Myoscint, Centocor, Leiden) was evaluated for efficacy in detecting cardiac allograft rejection. Diagnosis of rejection was made by endomyocardial biopsy with four to five samples taken for each procedure. Eighty-one studies were performed in 25 patients (21 men, four women, mean age 50 +/- 9 years) from 2 weeks to 45 months after cardiac transplantation. 0.5 mg of the monoclonal antibody labeled with 60 MBq Indium-111 (Antimyosin-Fab-DTPA) was administered i.v. Planar scintigraphic images were obtained in LAO 45 and anterior projections as well as "half-body-scintigrams" 48 h after injection. Using the regions-of-interest-(ROI)technique the relative uptake over the lung and the heart was determined and an index of In-111 uptake was calculated. A heart-to-lung ratio of 1.5 or higher was considered indicative for moderate to severe rejection. Specificity was 86% (nine false-positive In-111 studies in 68 negative biopsy studies), sensitivity was 85% (two false-negative In-111 studies in 13 pathological biopsy studies). It is concluded that the In-111 method has a high sensitivity and specificity in detecting heart transplant rejection and may be useful in the monitoring of patients in the chronic phase after heart transplantation. The 48-h delay in establishing the diagnosis limits the applicability in acute severe rejection.

Adult↗
PubMed1990

Comparison of three different principles in the assessment of coronary flow reserve from digital angiograms.

In 70 patients without coronary disease we have compared three different principles to assess coronary flow reserve during diagnostic heart catheterization. Digital angiograms with ECG-triggered bolus injections of 4 to 8 ml of contrast medium at rest and after stimulation by dipyridamole (0,5 mg/kg i.v.) or papaverine (12,5 mg i.c.) were acquired in a 512 x 512 matrix at 8 bit resolution (ADAC 4100) and stored on a digital disk at 25 frames/sec. or 2 frames/cardiac cycle (PPR-mode). Angiograms were processed by cyclic R-wave-gated mask mode subtraction and coronary flow in the LAD area was assessed by three different approaches: 1. A traditional densitometric principle. 2. The 'CMAP' principle. 3. A modification of the Stewart-Hamilton principle comparing the total amount of contrast medium that enters the coronary circulation to the area of the contrast dilution curve in a fixed portion of the LAD. Flow was measured simultaneously during angiography using the thermodilution technique for coronary sinus/great cardiac vein flow. Drug stimulation resulted in an increased coronary blood flow up to five times of resting flow. Regression analysis revealed the following results for the assessment of the coronary flow reserved by digital angiography (y) when compared to thermodilution (x): [table: see text] Method 2 could be improved by replacing the density factor by morphometrically measured proximal LAD volume (y = 0.77x + 0.55; r = 0.78; SEE = +/- 0.43). In conclusion, our data suggest that the Stewart-Hamilton principle may be advantageous over time parameter-dependent approaches in the assessment of coronary flow reserve by digital angiography.

Adult↗
PubMed1990

Protective effects of pretreatment with intracoronary nifedipine on myocardial ischemia and dysfunction.

To assess whether pretreatment with intracoronary nifedipine protects the myocardium against acute ischemia induced by coronary occlusion, 18 patients were studied during coronary angioplasty of the left anterior coronary artery. After a control occlusion of 60 seconds, 0.1 mg nifedipine was injected and occlusion was repeated for 60 seconds. Before and during the occlusion period, pulmonary capillary pressure was measured and the intracoronary epicardial ECG was recorded. After intracoronary administration of nifedipine, the onset of the rise in diastolic filling pressure was delayed from 23 to 38 seconds (p less than 0.01) and the changes at 60 seconds of occlusion were reduced from 14 to 11 mmHg (p less than 0.05). Nifedipine delayed the appearance of ischemic ST-segment elevation in the intracoronary ECG from 11 to 21 seconds (p less than 0.01) and diminished the changes at 60 seconds of occlusion from 1.8 to 1.2 mV (p less than 0.05). These findings suggest that pretreatment with intracoronary nifedipine protects the myocardium against some of the mechanical and electrocardiographic consequences of regional ischemia during acute coronary occlusion.

Adult↗
PubMed1990

Acute hypercalcemic crisis after an open heart operation.

Acute hyperparathyroidism developed in a previously normocalcemic 64-year-old woman during the first week after a coronary operation. Prolonged QT interval in the electrocardiogram and hypercalcemia were documented on the fourth postoperative day. Neck exploration on the fifth postoperative day revealed a lower right parathyroid adenoma. Parathyroidectomy resulted in rapid and dramatic improvement of the clinical picture and normalization of laboratory values.

Acute Disease↗
PubMed1990

Replication of hepatitis B virus in a hepatocellular carcinoma.

Hepatitis B virus transcripts and DNA from paired samples of neoplastic and nonneoplastic liver tissue of HBsAg seropositive patients were analyzed. The data obtained support the view that transcription of integrated DNA is frequent, both in neoplastic as well as in nonneoplastic liver tissue. In the case of one patient, integrated and free forms of hepatitis B virus DNA were detected in the tumor. Complete cycles of viral replication in this tumor were suggested by the following markers: (i) DNA and RNA intermediates expected to occur during replication of the viral genome, (ii) HBcAg and HBsAg, (iii) core and Dane particles. Viral DNA cloned from tumor tissue was proven to be replication competent in a transient replication assay. Five independent clones of viral DNA were established and found to be closely related at the nucleotide level. A preX open reading frame and a stop codon within preC were common features. In tissue surrounding the tumor, a nonreplicative state of virus infection prevailed, characterized by free viral DNA exclusively of the covalently closed, circular form. The replication of the viral DNA appeared to be blocked at the level of transcription.

Base Sequence↗
PubMed1990

Calcium overload in human giant cell myocarditis.

Myocardial calcium overload was observed in a patient with giant cell myocarditis. The myocardial calcium content estimated by atomic absorption spectrophotometry amounted to 120 mEq/kg dry weight, and the von Kossa stain disclosed multiple foci with patchy calcifications of myocardial fibres. Cytochemical examination of the ultrastructural calcium localisation using the phosphate-pyroantimonate method showed considerable variation in the subcellular calcium distribution. In normal myocytes calcium precipitates were confined to the inner leaflet of the sarcolemma, T-tubules, intercalated disks, and sporadically to mitochondria. In contrast, extensive calcification of mitochondria and loss of sarcolemmal calcium was evident in necrotic myocytes. A number of grossly normal myocytes also showed an increase of calcium precipitates in slightly swollen mitochondria. These findings suggest that myocardial calcium overload in this case started in viable myocytes and was not merely a secondary phenomenon occurring after cell death.

Calcinosis↗
PubMed1990

Mouse monoclonal antibody directed against hepatitis B virus X protein synthesized in Escherichia coli: detection of reactive antigen in liver cell carcinoma and chronic hepatitis.

A mouse monoclonal antibody directed against the protein product of the hepatitis B virus X open reading frame was prepared. This antibody was used to screen liver tissue sections from patients with chronic hepatitis (CH) and patients with liver cell carcinoma (LCC). Reactive antigen was detected by immunohistochemistry in about 30% auf the samples from CH patients and in about 80% of the samples from LCC patients regardless of whether tumor or surrounding nontumor tissue was analyzed. A predominant localization of the antigen in the cytoplasm was observed. In liver sections of CH patients the presence of HBx or HBx-related protein appeared to correlate with the presence of the classical viral antigens HBs- and/or HBcAg. A similar correlation was not found in liver or tumor tissue samples from LCC patients. The occurrence of X-monoclonal-antibody-reactive protein (Xarp) at a low frequency in liver tissue from patients without hepatitis B virus related disease suggests that Xarp in some cases may not be identical with the putative viral X antigen.

Animals↗
PubMed1990

[Evaluation of the biological exposure test "CS2 in urine"].

The necessity of integration of biological exposure tests, for example the BET "CS2 in urine", is shown in connection with the activities of the works doctor in order to evaluate the individual health risk of the exposed workers. The possibilities on principle for the tests are discussed Topical biological threshold limit values for CS2 in urine on the base of validity studies are presented. In addition a special intervention regime.

Air Pollutants, Occupational↗
PubMed1990

[Diagnosis of ventricular septum rupture following acute myocardial infarct using a fiber-optic indwelling catheter].

Rupture of the ventricular septum is a rare complication of acute myocardial infarction. Time of diagnosis, hemodynamic condition, as well as duration and effectiveness of the preoperative treatment determine the clinical outcome after surgical repair. Since its introduction the bedside-applied Swan-Ganz catheter has maintained an important role for the rapid confirmation and quantitation of the infarct-induced ventricular septal rupture. We report on the clinical courses of two patients whose diagnoses were established by means of a fiberoptic-armed Swan-Ganz catheter. Accuracy of the measured oxygen saturation was controlled by in vitro gas analyses with heparinized blood samples. As compared to conventional methods the continuous in vivo oximetry by a fiber-optic system is a simple procedure which facilitates repeated shunt calculations during hemodynamic monitoring in critically ill patients.

Catheterization, Swan-Ganz↗