Biomedical subjects
Publications and source records attributed to J Schneider.
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OBJECTIVES: The aim of this study was to perform a multiple logistic regression analysis to identify independent structural determinants of impaired left ventricular function. BACKGROUND: The association between contractile failure and structural alterations of the myocardium has been demonstrated in several studies, and multiple interactions between myocardial structure and cardiac performance are likely. METHODS: Morphometric data assessed from 130 left ventricular biopsy specimens were analyzed. The endomyocardial specimens were obtained from 57 patients with normal coronary arteries (17 with normal left ventricular ejection fraction and 40 with impaired left ventricular function [dilated cardiomyopathy]), 15 patients with hypertrophic cardiomyopathy and 32 patients with aortic valve disease. Transmural biopsy specimens were assessed in 6 donor hearts before heart transplantation and in 20 patients with left anterior descending coronary artery disease whose specimens were obtained from the left ventricular anterior wall during aortocoronary bypass surgery. Global or regional left ventricular function was evaluated from left cineventriculograms. The volume fraction of cardiac fibrous tissue, intracellular volume fraction of myofibrils, volume fraction of myofibrils related to myocardial tissue (including fibrosis) and myofiber diameters were determined from semithin sections of the biopsy specimens with the use of light microscopic morphometry. RESULTS: Multiple logistic regression analysis revealed decreased volume fraction of myofibrils (p < 0.005) and increased fiber diameter (p < 0.002) as independent determinants of impaired left ventricular function. CONCLUSIONS: These data indicate that, independent of the underlying heart disease, both decreased concentration of contractile proteins and myocyte hypertrophy are independently associated with impaired left ventricular function.
A total of 905 strains of several genera of the Actinomycetales were tested in respect to their sensitivity to genus- and species-specific actinophages. The results provided clear evidence that phage typing is a useful aid for the identification of actinomycetes. At the genus level, the specificity of actinophages has led to the correct placement of falsely identified strains, as well as to the rearrangement of genera. At the species level, however, phage typing has been less successful: only some actinophages are available so far, lysing strains (often not all) of one or a few related species (synonyms), e.g., of the genera Streptomyces and Amycolatopsis, as well as Saccharopolyspora.
Four years after an HIV infection and without any preceding illness characteristic of AIDS, a 24-year-old woman developed dyspnoea on exertion and peripheral oedema. She had for several years been an intravenous drug addict and contracted hepatitis A and B. There were no symptoms of the HIV infection. Clinical, radiological and echocardiographic examination demonstrated right ventricular failure caused by pulmonary hypertension not due to pulmonary embolism or another known aetiology. The patient died suddenly 9 months after the diagnosis from heart failure. Autopsy established primary pulmonary hypertension with pathognomonic plexogenic pulmonary arterial disease which had led to cor pulmonale with overload myocarditis. Although there had been no clinical signs of renal failure, there was histological evidence of mesangioproliferative glomerulonephritis and non-destructive interstitial nephritis. This case demonstrates that, in addition to the typical AIDS-associated diseases, other rarer syndromes may, in uncertain ways but connected with the HIV infection, decide the prognosis of such patients.
The heart of the elderly is characterized by increased occurrence of characteristic calcifications on mitral and aortic valves. These valves have been found calcified in persons older than 70 years at about equal frequency, in nearly 50% of these individuals simultaneously. A calcified mitral ring was more common in females of all age classes, aortic calcifications showed a less marked difference for gender. Only the most severe calcifications of the mitral ring have hemodynamic consequences. The clinical significance of these calcifications lie in their propensity for bacterial colonisation. The risk for infective endocarditis rises tenfold. Aortic valves, calcified by degenerative processes, lead to more pronounced alterations of hemodynamics. In nearly one half of the patients this type of calcification results in stenosis with corresponding left ventricular hypertrophy. Since coronary arteriosclerosis has a similar age distribution the risk for ischemic heart disease is increased. Early and particularly frequent calcifications of the aortic valve develop in patients with bicuspid valves. Risk for infective endocarditis is also raised by a factor of ten in patients with calcified aortic valve.
We present the case of an infertile patient, whose first attempt at IVF had to be postponed for 18 months due to a vulvovaginal yeast infection refractory to treatment. The main causative organism was a Candida glabrata strain resistant to all the imidazolic agents tested. The organism and the host's humoral status were studied in depth, looking for possible causes of the refractoriness to treatment.
Tissue samples of 21 HIV-positive patients have been studied for the presence and distribution of Epstein-Barr virus (EBV) subtypes A and B. This was done by PCR, EBER in situ hybridization, and immunohistochemical detection of EBV latent membrane protein (LMP) in AIDS-associated malignant lymphomas (16 cases) and lymphatic organs of patients without lymphoma (5 cases). Eleven cases were considered to be EBV-positive, with type A in four, and type B virus in four other cases. In patients with malignant lymphoma, EBV was localized in tumour tissue exclusively. One patient without lymphoma presented with multiple EBV genome type B-positive cells in all the lymphoid tissue samples examined. In HIV-positive patients, both subtypes of EBV, A and B, may play a role in the pathogenesis of lymphoproliferative lesions.
The antithrombotic efficacy of the prostacyclin analogue naxaprostene has been tested in rabbits with copper coil-induced carotid artery thrombosis. With oral pretreatment, 10 mg/kg naxaprostene prevented thrombotic arterial occlusion; with intraduodenal pretreatment the efficacy of naxaprostene was enhanced and 1 mg/kg was sufficient to exert an antithrombotic effect. The final average carotid blood flow at 180 min compared to the flow immediately before thrombus induction was 85 +/- 25% and 47 +/- 18% in animals treated with 10 mg/kg p.o. resp. 1 mg/kg i.d. naxaprostene. Parallel to the antithrombotic effect, naxaprostene inhibited ADP- and collagen-induced fall in circulating platelets. In anesthetized rabbits there was no dissociation between antithrombotic and hypotensive effects of naxaprostene.
R 79595 (N-cyclohexyl-N-methyl-2-[[[phenyl (1,2,3,5-tetrahydro-2 oxoimidazo [2,1-b]-quinazolin-7-yl) methylene] amin] oxy] acetamide) and its isomers represent a novel class of compounds with phosphodiesterase (PDE) inhibitory and cardiotonic (positive inotropic) actions. The cardiac effects of this class of compounds were investigated in the hexobarbital-depressed heart-lung preparation of the guinea-pig. After induction of heart failure (reduction of cardiac output to 25% of the initial value) cumulative addition of R 79595 or its isomers R 80122 (E-isomer) and R 80123 (Z-isomer) concentration-dependently reversed the cardiac depressant effects of hexobarbitone-Na. With regard to reconstitution of contractility and cardiac function R 80122 (E-isomer) was 10 fold more potent than R 79595 (1:1 mixture of the isomers) and nearly 100 fold more potent than R 80123 (Z-isomer). Furthermore, the cardiotonic action of the most potent isomer (R 80122) was compared to the effects of several positive inotropic reference compounds. The order of cardiotonic potency was as follows: (-)-adrenaline > R 80122 = adibendan > digitoxin > milrinone = enoximone > theophylline. Adibendan (EC50 value: 6.7 +/- 1.8 x 10.-8 mol/l), which showed cardiotonic effects in the same concentration range as R 80122 (EC50 value: 6.1 +/- 1.3 x 10(-8) mol/l), was significantly (p < 0.01) less effective than R 80122 with respect to the maximally induceable increase in cardiac output (CO). The cardiotonic effects of R 80122 could be observed in the low concentration range of 3 x 10(-8) to 1 x 10(-6) mol/l, whereas enoximone (EC50 value: 1.2 +/- 0.1 x 10(-5) mol/l) and milrinone (EC50 value: 8.9 +/- 3.5 x 10(-6) mol/l) elicited positive inotropic effects at 100 fold higher concentrations. Digitoxin was 10 fold less and theophylline was 300 fold less potent than R 80122 with regard to reconstitution of heart function. The cardiotonic effects of R 80122 were not accompanied by an increase in heart rate as found with milrinone, theophylline or (-)-adrenaline in this model. Furthermore, the PDE inhibitory effect of R 79595 and its E-isomer R 80122 were investigated in partially purified isoenzymes from guinea-pig ventricles. The IC50 values of R 79595 and R 80122 on PDE I-IV were compared to the IC50 values of adibendan, milrinone, enoximone and theophylline. The selectivity of an inhibitor for PDE III was evaluated by division of its IC50 values on PDE I, II and IV by the IC50 value on PDE III. R 80122 was the most potent and selective PDE III inhibitor.(ABSTRACT TRUNCATED AT 400 WORDS)
A recently proposed polythetic definition of virus species appears easily applicable to bacteriophages. Criteria for classification of tailed phages are evaluated. Morphology, DNA homology, and serology are the most important criteria for delineation of species, but no single criterion is satisfactory. Dot-blot hybridization and seroneutralization may suggest false relationships by detecting common sequences in the DNA of otherwise unrelated phages. Species of tailed phages can be defined by a combination of morphology and DNA homology or serology. A procedure for identification of novel phages is outlined. Phage names should include elements of host names.
Uterine cervical carcinomas and normal cervical tissue (controls) were investigated for the presence of the multi-drug-resistance gene product P-glycoprotein by means of immunohistochemistry, with the C219 monoclonal antibody and the streptavidin-biotin-peroxidase technique. Ten of 11 cervical carcinomas, 2 of which were previously treated with chemotherapeutic agents of the multi-drug-resistance group, showed a positive reaction of tumor cells. All normal controls showed a positive reaction of the ectocervical and endocervical epithelial cells. P-glycoprotein seems to be implicated at least in part in resistance to chemotherapy of cervical carcinoma.
The comparative metabolism of the carcinogenic pollutants 7H-dibenzo[c,g]-carbazole (DBC) and dibenz[a,j]acridine (DBA) was investigated in vitro using 3-methylcholanthrene (3MC) induced Sprague-Dawley rat and Hsd:ICR(Br) mouse liver microsomal preparations with benzo[a]pyrene (BaP) as the positive control. Metabolites were isolated and separated by HPLC and identified by spectroscopic and co-chromatographic techniques using synthetic standards. The major metabolites of DBC were the phenols: the 5-OH-DBC, 3-OH-DBC, and 2-OH-DBC. Traces of 1-OH-DBC were also found yet no dihydrodiols were identified. The major metabolites of DBA were the 3,4-diol-DBA and 5,6-diol-DBA, 1,2-diol-DBA, DBA-5,6-oxide and 4-OH-DBA. Treatment of both mice and rats with 3MC resulted in significant (P less than or equal to 0.05) increases relative to control in the microsomal metabolism of DBA to dihydrodiol and phenol metabolites, similar to that observed for BaP. 3MC-induced rat liver microsomes significantly (P less than or equal to 0.05) increased DBC metabolism relative to control microsomes whereas DBC metabolism was not increased with 3MC-induced mouse liver microsomes. These data indicate that different enzymatic pathways are involved in the metabolic activation of DBC in the Hsd:ICR(Br) mouse and Sprague-Dawley rat.
Intensive education of patients and physicians helps to increase the incidence of thrombolytic therapy in patients with myocardial infarction. Important factors in this process are: 1. Reduced delays in patients' awareness of the severity of his symptoms, 2. shorter time periods from patients' hospital admission to the initiation of thrombolytic therapy, 3. more indications by educated physicians with a higher degree of precision, and 4. reduced catalogue of contraindications.
Ultrasonography and manual palpation were used to evaluate the uterine cervix of 71 pregnant women between 14th and 36th week of gestational age. The sonographic length of the uterine cervix was about 4.2 cm according to the relevant cervix palpation (Group I), about 3.2 cm in the moderately shortened cervix (Group II) and about 2.8 cm in the severely shortened cervix (Group III). The distance between the surface of the ectocervix to the urinary bladder corresponded to the cervical palpation showing a constant difference of about 0.5 cm. No difference could be found in the width of the upper cervix. The index was determined as ratio of the sonographically ascertained cervical length and width of the supravaginal cervix. A value of 0.8 or lower describes a cervical incompetence of a higher degree and signifies an unfavourable prognosis. The evaluation of cervical incompetence and the relevance of the sonographically detected opened internal os have not yet been clarified. A hitherto unsolved problem is the dilatation of the cervical canal in case of immature palpatory findings with traumatic anamnesis.
OBJECTIVE: Vessel perforation and limited steerability of the laser light are the major limitations of laser angioplasty. To improve steerability fluorescence spectroscopy has been proposed for identification of atherosclerotic plaques. The aim was to investigate this. METHODS: Fluorescence spectroscopy with three different excitation wavelengths (325 nm, 380 nm, 450 nm) was tested in an emission range of 400 nm to 600 nm. Intensity ratios at 480/420 nm were determined in different types of blood vessels. Necropsy material from 40 patients (punch biopsies of 4 mm diameter from the coronary and carotid artery as well as from the ascending and descending aorta) was studied spectroscopically. Histological alterations of the vessel wall were assessed by a semiquantitative score (0 to 10 points): (a) normal tissue, 0 to 2 points (mean = 0.25; n = 38); (b) mild atherosclerotic lesions, 3 to 5 points (mean = 3.35; n = 39); (c) severe atherosclerotic lesions, greater than or equal to 6 points (mean = 6.75; n = 43). RESULTS: Best spectroscopic results were obtained with an excitation wavelength of 325 nm. In samples with severe atherosclerotic lesions the fluorescence spectra showed a significant reduction of the emitted wavelength intensities when compared to normal tissue. There was a clear separation of the fluorescence spectra between normal and mild as well as between normal and severe atherosclerotic lesions; normal tissue showed an increased intensity in the range from 420 nm to 540 nm, whereas atherosclerotic lesions had no or only a small peak at 480 nm. There was a significant correlation between the semiquantitative score (n = 120) and the fluorescence ratio at 480/420 nm (excitation wavelength 325 nm) with a correlation coefficient of 0.87. The spectroscopic results showed no differences between the samples taken from different types of vessels. CONCLUSIONS: Fluorescence spectroscopy allows a reliable identification of normal and atherosclerotic lesions. The close correlation between the emitted light intensity ratio at 480/420 nm and the histological alterations of the vessel wall suggests a relationship between vessel wall fluorescence and the atherosclerotic alterations of the wall.
The modification of estrogen and progesterone receptor status was prospectively studied in mammary carcinoma after short-term (7 days) administration of tamoxifen citrate (30 mg/day). Seventeen patients fulfilled the stringent criteria required for final evaluation. Tamoxifen was administered to them immediately prior to surgery and receptor status was studied on the surgical specimen. Estrogen receptor levels were significantly (p < 0.05) decreased after treatment, whereas progesterone receptors remained statistically unaltered, although they showed a tendency towards significant increase (p = 0.12). Following these results, short-term tamoxifen treatment seems inadequate for the induction of significant levels of progesterone receptors in mammary carcinoma.