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Biomedical subjects

K Simon

Publications and source records attributed to K Simon.

At least 91 records · Page 5Linked to original sources
PubMed1990

[A case of surgically treated septum perforation associated with acute myocardial infarct].

The authors present the case-history of an elderly female patient with acute myocardial infarction complicated by ventricular septal defect (VSD). She was operated on in order the VSD to be corrected but--probably because of sutural insufficiency--it temporarily reopened, later closed spontaneously. The significance of certain tests in the differential diagnosis of systolic murmur after acute myocardial infarction is discussed, and the importance of these findings compared to the clinical picture is emphasized.

Aged↗
PubMed1990

Dominant reduced responsiveness controlled by H-2(Kb)Ab. A new pattern evoked by Thy-1 antigen and F liver antigen.

In the most frequently used panel of H-2 recombinant strains, B10.A, B10.A(4R), B10.A(5R), and B10, inhibition of the immune response has hitherto mapped to H-2E. Inhibition of the responses to Thy-1 antigen and to F liver protein, as described here, maps in a novel pattern to H-2KbAb, and presumably to H-2Ab. Enhancement of the adoptively transferred anti-Thy-1 response by treatment with CD8-specific antibody suggests, very provisionally, that T cells with suppressive activity mediate the inhibition. The evolution of this new pattern, and of dominant reduced responsiveness in general, is discussed and its relevance to immunological diseases assessed. An enzyme-linked immunosorbent assay (ELISA) for F-specific antibodies is introduced.

Animals↗
PubMed1990

Lipopolysaccharide from Actinobacillus actinomycetemcomitans stimulates macrophages to produce interleukin-1 and tumor necrosis factor mRNA and protein.

Actinobacillus actinomycetemcomitans is associated with periodontal disease in children and adults. We report that low concentrations of lipopolysaccharide (LPS) from A. actinomycetemcomitans stimulated human macrophages to increase dramatically their accumulation of mRNA coding for interleukin-1 alpha (IL-1 alpha), IL-1 beta as well as tumor necrosis factor (TNF). Protein levels of IL-1 and TNF alpha also increased. Levels of these mRNAs increased by 4-5 fold as compared with unstimulated macrophages when these cells were cultured with as little as 2 ng/ml LPS from A. actinomycetemcomitans. Polymyxin binds and blocks the action of LPS; polymyxin inhibited the ability of LPS from A. actinomycetemcomitans to increase levels of IL-1 beta mRNA. The LPS of A. actinomycetemcomitans stimulated increased levels of IL-1 beta mRNA in the presence of cycloheximide, showing that stimulation by this LPS did not require new synthesis of protein. Furthermore, dexamethasone inhibited the ability of LPS from A. actinomycetemcomitans to stimulate the accumulation of mRNA coding for IL-1 beta. A. actinomycetemcomitans is an invasive microorganism of the gingiva; high intragingival numbers correlate with sites undergoing local destruction of the periodontium. IL-1 alpha, IL-1 beta, and TNF are potent monokines that mediate inflammation and resorption of bone. Out studies suggest that macrophages migrating to these gingival sites of A. actinomycetemcomitans infection will be stimulated by LPS of A. actinomycetemcomitans to produce IL-1 alpha, IL-1 beta and TNF. These cytokines will mediate gingival inflammation and stimulate resorption of alveolar bone.

Actinobacillus↗
PubMed1990

Modulation of interleukin-1 beta RNA in monocytic cells infected with human immunodeficiency virus-1.

The effect of HIV-1 infection on cytokine levels was studied in monocytic cells by using Northern blotting analysis. Monoblasts (THP-1, U937) did not express IL-1 beta RNA even if the cells were infected with HIV-1. After exposure to LPS (10 micrograms/ml) and 12-O-tetradecanoylphorbol-13-acetate (TPA, 100 nM) for 12 h, these HIV-1-infected monoblasts accumulated 8-15-fold greater levels of IL-1 beta RNA as compared with their HIV-1-uninfected counterparts that were similarly stimulated. In contrast, levels of RNAs coding for monocyte-colony-stimulating factor (M-CSF) and tumor necrosis factor-alpha (TNF alpha) were elevated less than twofold in the HIV-1-infected cells as compared with HIV-1-uninfected cells after their stimulation with LPS and TPA. Inhibition of new protein synthesis did not block the marked accumulation of IL-1 beta RNA produced by exposure to LPS and TPA in the HIV-1-infected cells. Time-course experiments showed that the maximal levels of IL-1 beta RNA occurred at 12 and 24 h after LPS and TPA stimulation of the HIV-1-infected and uninfected U937 cells, respectively. Studies of stability of RNA using actinomycin D showed that IL-1 beta RNA was equally stable in infected and uninfected U937 cells after their stimulation with TPA and LPS. Taken together, our data show that HIV-1 infection markedly augments IL-1 beta RNA accumulation in stimulated monocytic cells, probably through increasing rate of transcription of IL-1 beta.

Cell Line↗
PubMed1990

A case of funicular schwannoma.

A case of schwannoma in a 55-year-old male patient is reviewed. The diagnostic difficulties are pointed out in view of the literature. Currently, it is still difficult to form a diagnosis without operation either by physical examination or by other diagnostic procedures. That is the authors' point in reviewing their case. The castrated patient has been well and free of complaints for 5 years after operation with no recurrence.

Genital Neoplasms, Male↗
PubMed1990

[The effect of D-penicillamine on experimental liver cirrhosis induced by CCl4].

Authors examined the effect of D-penicillamin (Pw) on liver cirrhosis induced by chronic CCl4 and phenobarbital (Pb) treatment in Fischer 344 rats. Morphometric analysis of quantity of connective tissue fibres did not show decrease on the effect of Pe treatment. Quantity of hydroxiproline, which is one of the parameters of coll ahen decrease, did not change significantly on effect of drug, but only compared to CCl4 and Pb treated control. Quantity of glycosaminoglycan showed increase following Pe treatment. Lymphocyte stimulation by Con-A was different in CCl4 and Pb and Pe treated groups, respectively. According to our examinations in case of liver fibrosis cirrhosis induced by CCL4-PB treatment in rats the Pe treatment proved to be unsuccessful. It seems that Pe is effective only in forms of cirrhosis accompanied by significant copper accumulation, by decrease of toxic effects of copper.

Animals↗
PubMed1990

Purification of recombinant Mycobacterium leprae 65-kilodalton antigen and murine antibody responses to intravenously administered recombinant protein.

Recombinant Mycobacterium leprae 65-kilodalton antigen has been purified by a combination of differential solubility, ion-exchange and hydrophobic interaction chromatography, and a method for the quantification of the antigen in large scale protein preparations developed. By injecting large amounts of the recombinant antigen intravenously into mice, a limited degree of specific suppression of antibody-response has been induced.

Animals↗
PubMed1989

[Congenital saccharase-isomaltase defect--diagnostic difficulties].

Seven patients with congenital sucrase-isomaltase deficiency corresponding to the known diagnostic criteria and five patients having combined disaccharidase deficiencies with unusual pattern characterized by more pronounced sucrase than lactase deficiency were found among 505 children investigated by first jejunal biopsy. On the base of the case histories, the complications and the comparative evaluation of patient and control groups' data (the latter consisted of nine untreated coeliacs) the congenital sucrase-isomaltase deficiency was found to make the patients to be especially susceptible to enteral infections and consequently to postinfectious intestinal damages. These complicated cases do not correspond to the classic diagnostic criteria of the congenital enzyme deficiency causing diagnostic errors. In order to avoid the misdiagnoses the authors suggest modification of the diagnostic criteria of congenital sucrase-isomaltase deficiency as follows: the diagnosis of congenital enzyme deficiency might be verified in spite of mild histological signs and hypolactasia if the degree of lactase deficiency repeatedly and significantly is exceeded by the degree of sucrase deficiency.

Biopsy↗
PubMed1989

[ECG characteristics of acute myocardial ischemia].

UNLABELLED: The authors discussed the efficacy of ECG in distinction of reversible and irreversible myocardial damage. On the basis of continuous ECG monitoring of a patient, suffering from acute ischemic syndrome, it was established, that neither the appearance of R wave reduction nor that of the transient Q wave (besides the widely accepted ST segment elevation) do not signify the fact of transmural myocardial infarction. IN CONCLUSION: the classical rules in indication of myocardial rescue therapy should be expanded and ECG monitoring is of crucial importance in indication and evaluation of myocardial rescue therapy in acute myocardial ischemic syndrome.

Electrocardiography↗
PubMed1989

[New aspects of the Kearns-Sayre syndrome].

The case report of the 23 years old female with Kearn-Sayre syndrome started about 15 years ago has some special cardiological aspects. By His band ECG the height of III. degree atrioventricular block was located in the atrioventricular node which is in sharp contrast with all former findings localizing the block into or distal to His band. In the pathogenesis of the unexpected block localisation--besides the muscular degeneration accepted generally in KSS--the recent myocardial infarction of the patient could have a causal role. Electronmicroscopical investigation carried out on the biopsy specimen from the right ventricle revealed both the characteristic hallmarks of "generalized mitochondriopathy" and the pathological glycogen accumulation having been published in skeletal muscles before. The mitral valve prolaps diagnosed in the patient has never been mentioned in KSS. Trauma suffered in early childhood might have a pathogenetic role. In discordance with literature steroid treatment of the diabetic patient with KSS didn't result in lactacidosis.

Adult↗
PubMed1989

Molecular mechanics and X-ray crystal structure investigations on conformations of 11 beta substituted 4,9-dien-3-one steroids.

The influence of 11 beta-phenyl substitution upon 4,9-dien-3-one steroid-backbone conformations is calculated by means of the MM2p molecular mechanics scheme. In the case of steroids having a 13 beta configuration, the lowest strain energy is always evaluated for the conformational combination of rings A(inverted) B(normal) while, moreover, the 11 beta substitution increases the relative stability of the conformation A(normal) B(normal) compared to the nonsubstituted compound. Introduction of the 11 beta substituent causes some bowing of the energy-minimum structures in the A-ring region toward the beta side. For 13 alpha configurated steroids, the ring conformations A(inverted) B(normal) C(boat) and A(normal) B(inverted) C(twist/boat) are found to be energetically preferred. Quantitative description of different ring conformations using asymmetry and pseudorotational parameters as well as the comparison of molecular mechanics and available X-ray structure data give an impression of the conformational mobility. Whereas the effect of 11 beta substitution within a given ring conformation is limited, contributions to molecular flexibility can be found in the ability to adopt different basic conformations and in the occupation of near-minimum structures. An X-ray crystal structure analysis of a potential antiprogestational steroid has been performed, and the results are in good agreement with the calculated structure.

Crystallography↗
PubMed1989

Intestinal mast cells and neutrophil chemotactic activity of serum following a single challenge with gluten in celiac children on a gluten-free diet.

The number of one subtype of mast cells (formalin fixation, toluidine blue staining), cells of the lamina propria, and intraepithelial lymphocytes were counted in the intestinal biopsy specimens of 14 children with treated celiac disease following a single challenge with gluten. The serum neutrophil chemotactic activity was measured at 0, 1, 3, 5, and 24 h after challenge. There was no significant change in the number of intraepithelial lymphocytes, but the biopsy samples obtained at 5 h showed a marked increase in the inflammatory cells of the lamina propria and a significant decrease in the number of mast cells. A pronounced decrease was present at 3-5 h in the number of eosinophil cells in the blood. The neutrophil chemotactic activity of sera showed a significant increment in 10 of 14 patients. The intestinal permeability of patients became abnormal, as detected by the increased absorption of lactulose. These findings suggest that degranulation of mast cells may be involved in the pathogenesis of the small intestinal mucosal injury in children with celiac disease.

Adolescent↗
PubMed1989

[Incidence of markers of HBV and HAV infections in workers of the departments and clinics of anesthesiology and intensive care at the medical academy in Wrocław].

The frequency of markers of infection by hepatitis virus A and B was studied among the workers (physicians, nurses, auxiliary personnel) of the Chair and Department of Anaesthesiology and Intensive Therapy, Medical Academy in Wroclaw. Serological tests were done by the immunoenzymatic method using kits of Abbott Diagnostics Division. IgG anti-HAV antibodies were found in 62.8% of the tested subjects. HBV markers were present in 44.3% of the subjects, that is several times more frequently than in the general population. HBsAg carriers accounted for 4.3% of the whole group, while in 40% of the group anti-HBV antibodies were present in various combinations suggesting an immunity against HBV infection.

Adult↗
PubMed1988

Phase I clinical trial of a combination of dipyridamole and acivicin based upon inhibition of nucleoside salvage.

A Phase I clinical trial of simultaneous 72-h infusions of dipyridamole and acivicin was carried out in patients with advanced malignancies. The objective of this trial was to determine the maximum tolerated dose of dipyridamole when administered as a 72-h infusion in combination with acivicin. The development of this combination is of interest because of in vitro observations which demonstrate that dipyridamole potentiates the cytotoxic action of acivicin by blocking nucleoside salvage. Patients were treated with concomitant i.v. infusions of dipyridamole and acivicin for 72 h. The acivicin dose infused remained constant during the trial at 60 mg/m2/72 h. The maximum tolerated dose (MTD) of dipyridamole was 23.1 mg/kg/72 h. Limiting toxicities at the MTD of dipyridamole with acivicin were severe gastrointestinal and constitutional symptoms which appeared to be caused by the high doses of dipyridamole administered. Escalation of dipyridamole did not potentiate the mild myelosuppression or the neurotoxicity which occurs with acivicin alone. At a dose of dipyridamole which was well below the MTD, one patient experienced symptomatic orthostatic hypotension, and another patient with coronary artery disease developed dizziness and transient electrocardiogram abnormalities. However, no other hypotensive or cardiovascular events occurred as dipyridamole was escalated to the MTD. Phlebitis occurred at the site of infusion when the dose of dipyridamole exceeded 13.5 mg/kg/72 h. Because of this local toxicity, it was necessary to administer dipyridamole through a central venous catheter to achieve maximum plasma levels. At the MTD of dipyridamole, steady-state total and free plasma levels of 11.9 microM and 27.8 nM, respectively, were attained by 24 h. These are free dipyridamole levels which in vitro were sufficient to block cytidine salvage and to potentiate the biochemical and cytotoxic effects of acivicin against human colon cancer cells (P.H. Fischer et al., Cancer Res., 44:3355-3359, 1984).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

A block to the intracellular transport and assembly of hepatitis B surface antigen polypeptides in Xenopus oocytes.

Hepatitis B surface antigen is the major protein of the virion envelope, and is also independently secreted from infected cells as a subviral particle composed exclusively of HBsAg and host-derived lipid. Similar particles are efficiently assembled and secreted by cultured mammalian cells transfected with the gene for HBsAg. In contrast to such cultured cells, Xenopus oocytes microinjected with HBsAg mRNA secrete less than 5% of newly synthesized HBsAg polypeptides. We have examined the HBsAg biosynthetic intermediates in such oocytes and provide evidence that the impaired secretion of HBsAg is due to a discrete block in the assembly of lipoprotein particles.

Animals↗
PubMed1988

Secreted hepatitis B surface antigen polypeptides are derived from a transmembrane precursor.

Hepatitis B surface antigen (HBsAg), the major coat protein of hepatitis B virus, is also independently secreted from infected cells as a lipoprotein particle. Secretion proceeds without signal sequence removal or cleavage of other segments of the polypeptide. We have examined the synthesis and transport of HBsAg in cultured cells expressing the cloned surface antigen gene. Our results show that HBsAg is initially synthesized as a integral membrane protein. This transmembrane form is slowly converted to a secreted lipoprotein complex in the lumen of the endoplasmic reticulum via a series of definable intermediates, after which it is secreted from the cell. This unusual export process shares many features with the assembly and budding reactions of conventional enveloped animal viruses. However, it differs importantly in its absence of a requirement for the participation of nucleocapsid or other viral proteins.

Animals↗