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Biomedical subjects

A Laufer

Publications and source records attributed to A Laufer.

At least 19 recordsLinked to original sources
PubMed2000

Influence of diabetes on cardiac nitric oxide synthase expression and activity.

UNLABELLED: There is some evidence that the endothelium dependent vasodilatation of coronary arteries is impaired in both types of diabetes. The underlying mechanisms are not yet clear, in particular whether this defect is caused by a direct effect of diabetes on the activity and the expression of nitric oxide synthases (NOS) or indirectly by an enhanced inactivation of nitric oxide. METHODS: To study this question we determined the activity (conversion of L-arginine to citrulline) and the mRNAs encoding the isoforms of NOS (using polymerase chain reaction after reverse transcription of the mRNAs into cDNAs by reverse transcriptase) in hearts of streptozotocin diabetic rats and in rat heart endothelial cells (RHEC). The formation of reactive oxygen intermediates (ROI) was measured by the dichloro-dihydro-fluorescein method. RESULTS: The activity of total NOS and the amounts of mRNAs encoding ecNOS and iNOS were dependent on the duration of diabetes. After a diabetes duration of 4 to 6 weeks both the total activity as well as the mRNAs encoding ecNOS and iNOS were elevated. A reduction of NOS activity and the amounts of mRNAs of ecNOS and iNOS was only seen after a diabetes duration longer than 20 weeks, a time at which a loss of endothelium has been described. In RHEC, high glucose (22 mM) and H(2)O(2) (100 microM) were able to increase the mRNA encoding ecNOS, but not iNOS. This increase in ecNOS mRNA was inhibited by lipoic acid (1 microM). In addition, high glucose (22 and 30 mM) led to an enhanced formation of ROI and to activation of the transcription NF kappa B. CONCLUSION: These observations suggest that diabetes causes a temporary increase in NOS activity and ecNOS mRNA in the rat heart which is presumably the consequence of an enhanced oxidative stress exerted by hyperglycaemia. Together with previously published observations, our data suggest that the impairment of endothelium dependent vasodilatation in rat heart is not the consequence of a reduced activity and expression of NOS, but is caused by an enhanced inactivation of nitric oxide by ROI.

Animals↗
PubMed1985

Aggressive osteoblastoma. A case report and review of the literature.

A recurrent osteoblastoma involving the acetabulum in a 27-year-old woman was found to be locally aggressive and histologically appeared to become more anaplastic with each recurrence. However, there was no evidence of distant metastases. Similar cases have been reported under such names as pseudomalignant or malignant osteoblastoma. In view of the prolonged clinical course without evidence of distal metastases, the term "aggressive osteoblastoma" seems to be more appropriate. The treatment of choice for such tumors should be further en bloc resection, avoiding the morbidity and possible mortality of the chemotherapy demanded by true malignant tumor of bone, as well as unnecessary ablative surgery.

Acetabulum↗
PubMed1984

Antibodies to cultured rat heart cells in sera of patients with rheumatoid arthritis.

Since heart lesions occur in many patients with rheumatoid arthritis (RA), sera from these patients were tested with an indirect fluorescent technique for antibodies reactive with rat heart cell cultures. Of 27 sera 22 had reactivity with non-muscle (nM) cells and 3 reacted with cultured beating muscle cells (M). Positive sera reactive with nM cells exerted complement-dependent cell cytotoxicity towards M cells. The nM antibodies were found to belong predominantly to the IgG class. They displayed no cross-reactivity with bovine collagen, human and bovine serum proteins, or human and sheep red blood cells. The relationship of these antibodies to the pathogenesis of RA heart lesions remains to be determined.

Adult↗
PubMed1982

Diagnosis and classification of amyloidosis by an immuno-histological method.

Following the recent classification of amyloidosis by the amyloid proteins involved, we decided to approach its tissue diagnosis and chemical classification by an immunohistological method. Post-mortem tissue specimens from various organs of patients with primary and secondary amyloidosis were examined by the immunoperoxidase technique with specific antibodies against proteins AL and AA which respectively characterize primary and secondary amyloidosis. The major advantage of this technique is that it can be applied to formalin fixed, paraffin embedded tissues. The immunoperoxidase technique proved to be extremely sensitive for the detection of amyloid deposits. Moreover, the deposited proteins could be clearly characterized as AL or AA by the specific anti-sera. We therefore believe that the immunooperoxidase technique is extremely useful for the early tissue diagnosis and chemical classification of amyloidosis.

Amyloid↗
PubMed1980

Demonstration of amyloid in murine and human secondary amyloidosis by the immunoperoxidase technique.

A specific rabbit anti-murine amyloid A protein (anti-AA) has been used in the immunoperoxidase (IP) technique for the detection of amyloid in formalin-fixed, paraffin-embedded, tissue obtained from amyloidotic mice and a post-mortem kidney specimen from a patient with amyloidosis secondary to osteomyelitis. Amyloidosis was induced in five out of 20 white mice by weekly intraperitoneal injections of complete Freund's adjuvant. Amyloid deposits were clearly demonstrated both by the Congo Red and by the IP techniques. The antibody against murine AA was found to be cross-reactive with human AA. These preliminary results suggest that the IP technique with the use of specific antibodies against the different amyloid proteins might be extremely useful for the histological dianosis and classification of amyloidosis.

Amyloid↗
PubMed1978

Effect of papain on experimental amyloidosis.

Experimental amyloidosis was induced in mice by repeated injections of complete Freund's adjuvant (CFA) reinforced with a bacterial vaccine. Papain was administered i.p. at various time intervals during the treatment with CFA. Amyloidosis was found only in the spleen and the liver. No statistically significant differences were found between the papain-treated and the control groups. It is assumed that, although papain releaseed the polysaccharide moiety from the polysaccharide protein complex, the released polysaccharides were most probably bound by electrostatic forces to the amyloid fibres, and did not interfere with amyloidogenesis.

Amyloidosis↗
PubMed1978

Isolation of mycoplasmas from the genital tract of women with reproductive failure, sterility or vaginitis.

The presence of mycoplasma was investigated in 77 women with infertility, 34 women complaining of sterility, 92 women with vaginitis and 66 healthy control subjects. The group of infertile women was subdivided into those with one or two spontaneous abortions, those with three or more abortions and those with missed abortions. The isolation rate of mycoplasma from the vagina and cervix of the infertile women ranged from 18 to 36%. The endometrial isolation rate was 21% in women with missed abortions but lower in women of the other two subdivisions. Mycoplasmas were infrequently found in patients investigated for sterility. They were isolated at a higher rate in patients with vaginitis, especially in those with trichomonas-associated vaginitis. They were not found in healthy control subjects. In the endometria positive for mycoplasma no specific histological features for this infection were found.

Abortion, Spontaneous↗
PubMed1977

Fine structure of Sertoli and Leydig cells in azoospermic human testis.

Testicular biopsy specimens taken from seven patients with azoospermia were studied by electron microscopy. We considered the possibility of a relationship between the annulate lamellae in the Sertoli cells and azoospermia. In the Leydig cells, we observed intranuclear and intracytoplasmic paracrystalline inclusions and considered their relationship with the Reinke crystalloid.

Adult↗
PubMed1977

[Methods and indications for low peridural analgesia in the aged. Report of 300 cases].

Continuous peridural analgesia took a long time to be accepted in current practice in surgery of the elderly, owing to the apprehensions for the possible cardiovascular consequences and also, the difficulty in using this form of anaesthesia in the elderly. The experience of more than 300 cases, collected in the Nice department of Anesthetics and Intensive Care, has shown that: 1--technical failures are exceptional with routine use of prior epidurography; 2--its indications depend on the site and type of surgery and on the clinical conditions of the patient; 3--until now, there have been no severe complications due to this method whatever the degree and number of morbid conditions; 4--in the elderly subject, the importance of problems of pre and post-operative analgesia have led us to enlarge the indications for long-term peridural analgesia. Peridural anesthesia may be used as a routine when the site of the operation involves areas situated below the IXth metamere. This shows its importance in surgery in the elderly.

Aged↗
PubMed1975

Histochemical studies of human breast tumors: Activity of alkaline phosphatase, acid phosphatase and glucose-6-phosphate dehydrogenase.

Histochemical studies of human breast tumors were performed with particular emphasis on the activity of alkaline phosphatase (AIP), acid phosphatase (AcP) and glucose-6-phosphate dehydrogenase (G6PDH). Enzyme activities in benign and malignant lesions were compared. AIP was prominent in normal mammary epithelium, limited to the myoepithelial layer in benign tumors and was absent in cords of malignant cells. AcP activity was faintly detected in normal mammary epithelium, increased in canalicular epithelium of fibroadenomas and was marked in malignant cells. G6PDH exhibited marked activity in neoplastic epithelium and the stroma of nearly all carcinomas studied, whereas in benign tumors, G6PDH activity was strictly limited to the connective tissue. The study suggests a strong correlation between G6PDH activity and malignancy. The different results obtained by various workers in this field are critically reviewed, and discussed in the light of the results of the present study.

Acid Phosphatase↗
PubMed1975

The effect of beta aminoproprionitrile (BAPN) on experimental amyloidosis.

Experimental amyloidosis was induced in mice with repeated injections of complete Freund's adjuvant (CFA) reinforced with bacterial vaccine. BAPN administered in a mixture with CFA or on its own before the injection of CFA reduced the incidence of amyloidosis. The reduction in the incidence of amyloidosis following the administration of BAPN may be due to its inhibitory effect on the oxidative deamination of amino acids, which presumably inhibit cross-linking of amyloid fibrils or interfere with metabolic pathways which involve the formations of mucopolysaccharide formation. It is suggested that the defective formation of the mucopolysaccharide-amyloid protein complex inhibits amyloid deposition and induces the activity of beta glucuronidase observed in the present study. The reduced incidence of amyloidosis following BAPN adminsitration cannot be due to lysosomal enzyme degradation of the amyloid as the activity of cathepsin D and acid phosphatase is decreased during this process.

Acid Phosphatase↗