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Biomedical subjects

M Cao

Publications and source records attributed to M Cao.

72 records · Page 4Linked to original sources
PubMed1991

[Localization of antigen and antibodies in the liver and intestine of mice with Schistosoma japonicum].

Indirect fluorescent antibody test was used to localize the antigen in the livers and intestines of mice with Schistosoma japonicum. No antigen was detected 4 weeks p.i.. There was a significant rise in antigen level 6 weeks p.i. which reached peak level 10-12 weeks p.i., the GMRT being 512 and 483, respectively. The eggs in the tissues showed strong fluorescent reaction 6 weeks p.i.. The mean diameter of schistosome egg granulomas in the livers and intestines of infected mice was remarkably enlarged 6 weeks after infection. The mean diameter of egg granulomas in the livers was markedly larger than that in the intestines. The antibodies were localized in the livers and intestines of infected mice as shown by the direct fluorescent antibody test (DFAT) and IFAT. The results indicated that the levels of IgG, IgM and IgA antibodies appeared 6 weeks p.i. which went on a significant increase at the 10-12 weeks. The IgG antibody level was higher than that of other two antibodies. It is suggested that the IgG may be the main antibody in the immunologic response of Sj egg granulomas.

Animals↗
PubMed1989

Enhancing effects of immunoactive peptide FR48217 on immunological responses to vaccination by inactivated influenza virus.

The adjuvant effect of an immunoactive peptide, FR48217 (FR), was investigated in mice vaccinated with inactivated influenza virus with and without FR (designated as V + FR and V - FR, respectively). Mice were infected with influenza virus A/PR/8/34 28 days after vaccination. The survival rate indicated a strong adjuvant effect of FR on vaccination with inactivated influenza virus. No difference in interferon activity in the pulmonary lavage fluid was found between the V + FR and V - FR groups. The titres of virus-specific IgA and IgG antibodies in the serum increased after vaccination in both V + FR and V - FR groups and were significantly higher in the V + FR group than in the V - FR group. On days 2 and 4 after viral infection, the serum antibody titres decreased sharply and then increased again rapidly. The free IgA and IgG antibody levels in the pulmonary lavage fluid of vaccinated mice started to increase after day 4. It is proposed that one of the mechanisms by which FR has the adjuvant effect on vaccination is the increase of virus-specific IgA and IgG antibodies in the serum, which are diffused into the infection sites of the epithelial tissues in the respiratory tract to neutralize the virus at the early stages of viral infection.

Adjuvants, Immunologic↗
PubMed1989

Isolation and expression of the Pneumocystis carinii dihydrofolate reductase gene.

Pneumocystis carinii dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) cDNA sequences have been isolated by their ability to confer trimethoprim resistance to Escherichia coli. Consistent with the recent conclusion that P. carinii is a member of the Fungi, sequence analysis and chromosomal localization show that DHFR is neither physically nor genetically linked to thymidylate synthase. Expression of recombinant P. carinii DHFR in heterologous hosts provides an abundant source of the enzyme that may form a basis for the development of new therapies for this enigmatic pathogen. Studies with the recombinant enzyme show that trimethoprim is a very poor inhibitor of P. carinii DHFR and, in fact, is a more potent inhibitor of human DHFR.

Amino Acid Sequence↗
PubMed1989

Rapid detection of cutaneous herpes simplex virus infection with the polymerase chain reaction.

A simple and specific method for detecting herpes simplex virus infection in routinely processed paraffin-embedded biopsy specimens is described. DNA is extracted from paraffin blocks, and subjected to DNA amplification with the polymerase chain reaction. After 40 rounds, an amplified band can be detected after agarose gel electrophoresis and ethidium bromide staining. This band is specific for herpes simplex virus, because tissues infected with related viruses do not give this amplified band. We have been able to detect viral DNA in small punch skin biopsies with this procedure, which can take as little as 6 h.

DNA, Viral↗
PubMed1989

Localization of cytomegalovirus DNA in plastic-embedded sections by in situ hybridization. A methodologic study.

The use of in situ hybridization for the identification of specific nucleic acid sequences in tissue sections has the potential for broad application in pathology. Although this technique has been successfully applied to routine paraffin sections, there have been few studies of the application of in situ hybridization to plastic-embedded tissue sections. The authors adapted techniques developed for paraffin sections to take advantage of the potential for improved morphology and more precise localization inherent in the plastic sections. A commercially available biotinylated DNA probe specific for the cytomegalovirus to develop a practical method for detection of nucleic acid sequences in plastic-embedded tissues was used. Using plastic sections, cytomegalovirus DNA sequences could readily be identified with precise localization of the virus and superb histology.

Biotin↗
PubMed1984

Resolution of brain edema in severe brain injury at controlled high and low intracranial pressures.

A series of 87 patients with severe brain injury were studied. Intracranial pressure (ICP) monitoring and external ventricular drainage were used to control ICP at high and low levels. Clearance of ytterbium-169-labeled diethylenetriaminepentaacetic acid (169Yb-DTPA), Evans blue dye, and ventricular cerebrospinal fluid protein was measured at the two ICP levels over consecutive periods of 4 hours to confirm clearance of brain edema. The results support the hypothesis that brain edema is in part absorbed in the cerebrospinal fluid via transventricular flow.

Adolescent↗
PubMedDate not supplied

SCG10, a neuron-specific growth-associated protein in Alzheimer's disease.

Neuronal growth-associated proteins (nGAPs) are markers of neuronal process outgrowth and are associated with both degenerative and sprouting responses in Alzheimer's disease (AD) brain. To study possible involvement of SCG10, an nGAP, in AD, we cloned human SCG10 cDNA and analyzed SCG-10 at mRNA and protein levels in control and AD brains. The deduced amino acid sequence of human SCG10 was 69% identical to stathmin, another nGAP. By in situ hybridization, both SCG10 and stathmin mRNAs were detected in selected neuronal populations in aged human brains. Quantitative analysis by RNase protection revealed that levels of neither SCG10 nor stathmin mRNAs were significantly altered in AD. Using an SCG10-specific antibody, Western blot analysis did not reveal any quantitative changes of SCG10 in AD. However, when the concentration of SCG10 protein was plotted against the number of tangles, a positive correlation was found. SCG10 levels did not correlate with plaque numbers. Furthermore, immunohistochemical study revealed that neuronal SCG10 protein accumulated in the cell bodies in AD-affected regions. Thus, SCG10 compartmentalization and metabolism may be altered in AD possibly due to mechanisms related to tangle formation in this disease.

Alzheimer Disease↗
PubMedDate not supplied

Does nitric oxide help explain the differential healing capacity of the anterior cruciate, posterior cruciate, and medial collateral ligaments?

This study compared the ability of rabbit medial collateral ligament, posterior cruciate ligament, and anterior cruciate ligament tissue to synthesize nitric oxide, and determined its effects on matrix synthesis, an important component of ligament repair. It is not known whether ligament cells can produce nitric oxide and, if so, whether it influences healing of ligament injuries. The anterior cruciate and posterior cruciate ligament tissue produced large amounts of nitric oxide in response to the inflammatory cytokine interleukin-1. Medial collateral ligament, in contrast, produced only modest amounts of nitric oxide. Furthermore, anterior cruciate ligament and, to some degree, posterior cruciate ligament synthesized nitric oxide spontaneously in culture, whereas medial collateral ligament never did so. When nitric oxide was supplied to these tissues, it strongly inhibited collagen synthesis by the two cruciate ligaments, but had little effect on collagen synthesis by the medial collateral ligament. Endogenously synthesized nitric oxide was also able to inhibit collagen synthesis as well as proteoglycan synthesis by the two cruciate ligaments, but had little effect on matrix synthesis by the medial collateral ligament. We propose a novel hypothesis, based on nitric oxide production and matrix synthesis, that may help explain why the two cruciate ligaments have such limited healing capacity compared with the medial collateral ligament.

Animals↗
PubMedDate not supplied

[Stroke in the young: a diagnostic protocol].

This study attempts to propose guidelines for diagnostic procedures in young adults with focal cerebral ischemia. Our data indicate that the most common etiologies are atherothrombosis (primarily in 40-47-year-old subjects), and cardioembolism (more prevalent in subjects under 30 years old). Autoimmune conditions were observed in 12.6%, and arterial dissections in 11% of our patients. Despite extensive diagnostic studies, we were unable to determine the etiology of the cerebral ischemic event in 10% of our patients.

Adolescent↗