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Biomedical subjects

M Kremer

Publications and source records attributed to M Kremer.

At least 73 records · Page 4Linked to original sources
PubMed1994

The 140-kDa protein of blood-brain barrier-associated pericytes is identical to aminopeptidase N.

Although ample evidence has been accumulated on the structure and functional role of endothelial cells in blood-brain barrier mechanisms, little is known about the contribution that cerebral pericytes provide to this phenomenon. We have reported recently on a monoclonal antibody specific for cerebral pericytes at blood-brain barrier sites. To confirm the pericytic localization of this antigen, and in order to elucidate its biochemical identity, we have performed immunocytochemical, biochemical, and molecular biological studies. By immunocytochemistry on the light microscopic as well as electron microscopic level, we provide definite evidence that the 140-kDa antigen recognized by this monoclonal antibody is confined to cerebral pericytes, whereas endothelial cells are devoid of this antigen. N-Terminal sequencing of the corresponding immunocrossreacting renal protein revealed that the protein detected by the monoclonal antibody is identical to aminopeptidase N. By means of the reverse transcriptase-polymerase chain reaction, the identity of the 140-kDa antigen as aminopeptidase N could also be verified for cerebral microvascular cells. Cerebral pericytic aminopeptidase N may be involved in neurotransmitter (enkephalin) metabolism at the blood-brain interface. By taking into account that brain pericytes have been found to express further plasma membrane-bound enzymes, these results strongly suggest the contribution of cerebral pericytes in the metabolic concert of the homeostatic balance regulated by the blood-brain barrier.

Amino Acid Sequence↗
PubMed1994

Strongyloides stercoralis infection in a non-immunosuppressed tourist with involvement of the central nervous system.

In the present case report a 50-year-old woman is presented with a Strongyloides stercoralis infection after a one-month stay in Sri Lanka. She showed a severe involvement of the central nervous system without a correlation of an immunosuppression. Strongyloides stercoralis is regarded as the cause of the cerebral involvement. Other possible causes are also discussed.

Animals↗
PubMed1994

Anesthesia and interventional angiography.

Nonsurgical anesthesia services may be requested by interventional angiographers specializing in the treatment of either visceral or central nervous system lesions. Procedures commonly performed in some angiography laboratories are discussed along with associated physiological alterations and anesthetic implications for interventional angiographic undertakings. These cases include: hepatic artery embolization; the transjugular intrahepatic shunt procedure, and transcatheter therapy of intracranial and extracranial lesions. Anesthetic approaches are suggested for these procedures based on the author's experience with them and anesthetic practice at a major medical center in the northwest.

Anesthesia↗
PubMed1993

Asymptomatic oral Candida albicans carriage in HIV-infection: frequency and predisposing factors.

Many studies have focused on the epidemiology and pathogenesis of oral candidiasis in HIV infection. Little is known on the incidence and predisposing factors of asymptomatic oral candida carriage in this setting, obviously an important issue in view of prophylaxis. To address this question, 261 consecutive HIV-infected individuals without clinical evidence of candidiasis were investigated. C. albicans was isolated from cultured oral cavity swabs of 63 subjects (24%). Colonization was significantly more frequent in IV drug users, CDC groups IV, and in subjects with lymphocytopenia, CD4+ cell depletion, or elevated beta-2 microglobulin. These data further suggest that oral candidiasis occurs in HIV infection as a result of C. albicans overgrowth and raise the question of primary antifungal prophylaxis in subjects with low CD4 counts and asymptomatic oral Candida carriage.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Coprological evaluation of refugees in Strasbourg between January 1986 and December 1990].

1,000 refugees living in Strasbourg have had a stoll parasitologic exam between 1986 and 1990. We have not retained results of South America and other areas of Asia subjects because of their scarce total number. Proportionally, the most numerous are the South East Asia Nationals (51.7%); followed by those from Middle East and Africa (20 and 15.5%) and more recently by those from East of Europe (5.2%). Their parasitic infestation's rate remains important (60.9%) but variable depending on their origin. Thus, people coming from Middle East and Africa are parasited mainly by protozoan, although those from South East Asia are parasited by helminths. It's interesant to notify that the prevalence of D. fragilis is ten times higher among East European people than in the common people.

Africa↗
PubMed1992

Pattern of glucose transporter (Glut 1) expression in embryonic brains is related to maturation of blood-brain barrier tightness.

A constant supply of blood-borne glucose is vital to cerebral metabolism. Although transport of glucose into the nervous tissue, effectively separated from the blood by a functional barrier (the blood-brain barrier, BBB), is one of the essential properties of the cerebral endothelium, little is known about its metabolic regulation and developmental expression in the BBB. In this study we provide evidence by immunocytochemistry that the pattern of the brain endothelial glucose transporter in rat brains (BBB-GT), immunologically homologous with the human hepatoma (G2), human erythrocyte transporter (Glut 1), changes with BBB maturation. While the neuroepithelium at embryonic days 12 and 13 shows a high incidence of immuno-detectable BBB-GT, vascularisation of the cerebral anlage and subsequent development of vascular tightness, as evidenced by intravascularly applied horseradish peroxidase and fluorescinated dextrans, is accompanied by a significant reduction of BBB-GT expression in neuroepithelial cells and confinement of BBB-GT expression to the cerebral endothelium. Immunoblots and Northern blots of embryonic brain homogenates corroborate this change in BBB-GT expression in the brain anlage at the time of BBB maturation. However, low molecular weight glucose transporters, presumed to be of non-endothelial origin, are less dramatically reduced. The development of BBB tightness, therefore, seems to play a pivotal role in the pattern of BBB-GT expression during brain differentiation.

Animals↗
PubMed1992

MIBG scintigraphy of a patient with pheochromocytoma on labetalol therapy.

A patient with pheochromocytoma was studied by MIBG scintigraphy while on labetalol therapy, which has been reported to interfere with imaging. Serial imaging was performed at 2, 18, 25, and 90 hours to obtain time/activity curves. Blood samples were taken at each imaging study to determine activity counts. Tumor activity per gram of tissue (surgery 116 hours after injection) was compared with blood activity. Tumor and blood activity decreased concurrently, whereas the decrease in peritumoral activity was faster, thus providing transiently improved contrast on 18- and 25-hour images. The diagnostic implications of these results are discussed.

3-Iodobenzylguanidine↗
PubMed1992

Comparison of lipids from epidermal and palatal stratum corneum.

Stratum corneum has been isolated by tryptic digestion of porcine epidermis and palatal epithelium, and the lipid concentrations and compositions have been compared by thin-layer chromatography in conjunction with photodensitometry. Palatal stratum corneum contained 47 +/- 6 micrograms lipid/mg tissue or 115 +/- 16 micrograms lipid per cm2 of stratum corneum surface, whereas epidermal stratum corneum contained 105 +/- 17 micrograms lipid/mg tissue or 135 +/- 16 micrograms/cm2. The difference in total lipid content does not account for the tenfold higher permeability constant for the permeation of water through the former tissue compared to the latter; therefore, the difference in permeability must be based on differences in lipid composition. In this regard, palatal stratum corneum includes 12.1% phospholipids, although phospholipids were undetected in epidermal stratum corneum. Differences in the content and location of non-polar liquid-phase lipids may also be of significance for permeability. Other factors that may contribute to the greater permeability of the palatal horny layer relative to epidermal stratum corneum include generally lower proportions of cholesterol, fatty acids, and ceramides, a dramatically lower proportion of the linoleate-containing acylceramide, and a tenfold lower content of covalently bound lipids associated with the corneocyte envelope.

Animals↗
PubMed1991

A new tumor-associated antigen expressed on breast carcinomas, defined by monoclonal antibody BCA 227.

After immunization of mice with the human breast carcinoma cell line MCF-7, we produced monoclonal antibody (mAb) BCA 227, which allowed us to characterize a new tumor-associated antigen. This molecule is strongly expressed by well differentiated mammary carcinoma cell lines and by some other tumor cell lines of epithelial origin. Immunohistological study of frozen sections of different tissues and tumors confirmed its expression by tumor cells of epithelial origin, particularly infiltrating duct carcinomas of the breast. The antigen is also expressed, to a lesser extent, by some normal epithelial cells. Its biochemical characterization revealed a Mr 71,000 protein without an N-linked sugar moiety. Six to 40 x 10(3) binding sites are present on breast tumor cell surfaces. Although mAb BCA 227, which was found to be of the IgG2a isotype, did not mediate antibody-dependent cell-mediated cytotoxicity with either human or mouse effector cells, a 50% inhibition of SK-BR5 tumor growth was obtained in nude mice, suggesting that another mechanism is responsible for this inhibition. Biodistribution studies of radiolabeled F(ab')2 fragments of mAb BCA 227 in tumor-bearing nude mice showed a preferential localization in the tumor. All these data are in favor of the use of mAb BCA 227 as an immunodiagnostic tool for breast cancer.

Animals↗
PubMed1991

Long-term antimicrobial therapy in the prevention of recurrent soft-tissue infections.

Thirty-six patients who had suffered two or more episodes of erysipelas or cellulitis during the previous year were randomly divided into two equal groups; one group received erythromycin base 250 mg b.i.d. for 18 months, while the other group received no prophylaxis for a similar period. No patients in the treated group developed infection during the 18 months' follow-up but eight of the control group (50%) relapsed and required antibiotic treatment. Prolonged antimicrobial prophylaxis is effective and safe in preventing recurrent episodes of soft-tissue infections.

Cellulitis↗
PubMed1991

[Fixation of Indium111-labeled antifibrin monoclonal antibody on the vegetation in endocarditis: evaluation in a rabbit model].

The uptake of a 111In labelled antifibrin antibody was studied in left ventricle endocarditis on a rabbit model. The immunospecificity of the antibody for the cardiac vegetations is favorable, exhibiting an uptake at least 4 times that of blood, or myocardium. A planar scintigraphy of the opened left ventricle showed a radionuclide imaging of vegetations, according to anatomical lesions. The use of antifibrin monoclonal antibodies could prove helpful to improve the specificity of valvular lesions visualized by echocardiography, or to detect the small vegetations at the early stage of acute endocarditis.

Animals↗
PubMed1991

Morphological investigations on the small intestinal mucosa of mouse after mild hyperthermic treatment.

Local hyperthermia, when applied as a therapeutic agent against radio-resistant tumours, can result in serious side effects in adjacent non-tumorous tissue, one especially thermo-sensitive organ being the small intestine. An experimental morphological study was therefore undertaken with mice to investigate whether "mild hyperthermia" (41 degrees C for 15, 30 and 60 min) causes alterations at the mucosa of the small intestine, and if so what are these effects and their likely pathomechanisms. Descriptive light and electron microscopical studies and morphometric evaluations are reported on the jejunal mucosa. The observed changes were most extensive after 60 min of 41 degrees C hyperthermia; but even 30 and 15 min hyperthermic treatment was followed by severe degenerative changes. The epithelium of the basal crypts and the stromal cells seemed to remain morphologically unaffected under these conditions, though the stroma can react with a temporary contraction. No "prime event" in the hyperthermia provoked tissue changes can be deducted from the combined light, electron microscopical, and morphometric studies. Comparing, however, the extent of the effects after mild hyperthermia of 60, 30 and 15 min, respectively, four phases of intestinal alterations due to mild hyperthermia and a likely pathomechanism of this treatment can be defined. The clinical implications of the findings are discussed.

Animals↗
PubMed1990

Feasibility study of radioimmunoguided surgery of colorectal carcinomas using indium-111 CEA-specific monoclonal antibody.

The study was undertaken to define the potential use of indium 111 carcinoembryonic antigen-specific antibody labelled [CEA F(ab')2] for the radioimmuno-detection of colorectal carcinoma using an intraoperative hand-held gamma probe. The use of a linear radioactive source allowed optimization of physical characteristics. The best results regarding sensitivity and resolution were obtained using a 5-mm thick tungsten alloy collimator. A simulation study with a liver phantom (22 MBq or 0.6 mCi) was performed to determine the effect of side scatter as opposed to direct background and showed that it is possible to detect small radioactive targets (3.7 KBq or 0.1 mu Ci) 4 cm from the phantom. A clinical study performed with ten patients showed that tumours with good uptake of CEA-specific antibody could be detected with sufficient contrast in two patients when the probe was used. Results of a biodistribution study performed after tumour fragment or normal tissue countings in a well counter showed high tumour uptake (above 8 x 10(-3) injected dose/g) and tumour-to-normal tissue ratios (between 2.5 and 20) in five patients. Results with the probe showed markedly lower ratios. There was no correlation between absolute tumour uptake and the count rates of tumour measured intraoperatively. This can be attributed to the degradation of depth resolution resulting from the high energy photopeak of gamma-emitting 111In.

Adenocarcinoma↗