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Biomedical subjects

H Z Yin

Publications and source records attributed to H Z Yin.

26 records · Page 2Linked to original sources
PubMed1994

Basal forebrain cholinergic neurons are selectively vulnerable to AMPA/kainate receptor-mediated neurotoxicity.

We exposed murine basal forebrain neuronal cultures for 24 h to defined concentrations of N-methyl-D-aspartate, kainate or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, and assessed the resultant degeneration of the cholinergic neuronal subpopulation, as identified by choline acetyltransferase immunocytochemistry and acetylcholinesterase histochemistry. Cholinergic neurons, representing about 0.5% of the total neuronal population, were atypically vulnerable to excitotoxins. Compared to most basal forebrain neurons, they were more vulnerable to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate receptor-mediated injury and slightly less vulnerable to N-methyl-D-aspartate receptor-mediated injury. The present findings provide quantitative demonstration of a mechanism that preferentially injures basal forebrain cholinergic neurons, and may thus suggest candidate factors pertaining to their loss in disease states like Alzheimer's disease.

Acetylcholine↗
PubMed1993

PCR amplification of HIV and cellular DNA sequences in formaldehyde-fixed, immunoreactive white blood cells.

Full utilization of the diagnostic power of PCR amplification of specific DNA sequences has been hampered by the logistical difficulties in handling potentially infectious human DNAs and by the polymerization of nonspecific, competing DNA products in PCR assays of low-frequency DNA sequences. To overcome these difficulties, we have devised a sensitive, specific PCR strategy that readily detects 5 copies of HIV provirus in a background of 10(5) disinfected white blood cells collected from formaldehyde-fixed peripheral blood.

Base Sequence↗
PubMed1993

Formaldehyde-fixed semen is suitable and safer for leukocyte detection and DNA amplification.

This pilot study indicates the use of formalin-fixation may offer a significant advance in the cytologic and pathological evaluation of semen. We are reporting this novel method to stimulate further assessment of this safer approach to semen analysis. The immunohistochemistry and PCR methods described here may also prove useful in improving the safety of studies of pathogen-infected cells in other laboratory settings.

Antibodies, Monoclonal↗
PubMed1990

Gelatinolytic proteinase activities in human seminal plasma.

Proteinase activities in human seminal plasma were detected using gelatin-containing sodium dodecyl sulphate-polyacrylamide gel electrophoresis zymography. Three prominent bands of activity of Mr 60,000, 66,000 and 90,000 were observed as well as 9 other bands of less intensity (34,000-158,000). These proteinases were dependent upon calcium for optimal activity, did not hydrolyse casein, and were predominantly in the soluble portion of seminal plasma. Examination of seminal plasma of men with different sperm concentrations, split ejaculates, and prostatic secretions indicated that the prostate gland was a source of most of these activities. Proteinase activities of Mr 34,000, 37,000, 82,000 and 120,000 were expressed more frequently in seminal plasma from normozoospermic men than from seminal plasma of oligo- or azoospermic men, indicating that they may also arise from spermatozoa in the semen sample. The proteinases of Mr 60,000 and 66,000 were found in all seminal plasmas whereas there was variation in the expression of the other molecular forms of enzyme, even in the normozoospermic samples. There are multiple forms of gelatinolytic proteinase activities in human seminal plasma which appear to arise from multiple sources in the reproductive tract including the Cowper's/urethral glands, the prostate gland, seminal vesicle and/or spermatozoa. Their function(s) in semen remains to be established.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

[Studies on the karyotypes of Fasciola spp].

The karyotypes of diploid and triploid forms of the common liver fluke were analysed by air-drying method. The chromosome number of diploid form was 2n = 20, n = 10, and the karyotype consists of the chromosomes with 2M, 4Sm, 3St, 1T. There were a number of similarities between the karyotypes of diploid form and triploid form except that the chromosome number of the triploid was 3n = 30 and n = 10. Judging from the shape of adult worms and their life cycle, the worm of the diploid form is similar to F. gigantica while the worm of the triploid form is similar to F. hepatica. In several specimens of the triploid worms there were some cells having 20 chromosomes that were composed of 10 monovalent chromosomes and 10 divalent chromosomes. This kind of cell, in a group of 8 cells, was primary spermatocyte. According to the measurement, these chromosomes could be classified into 10 pairs and each pair was made up by one monovalent chromosome and one divalent chromosome. The karyotype of these chromosomes was similar to that of the triploid form. It is a rare phenomenon that one set of monovalent chromosomes and one set of divalent chromosomes co-exist during the same metaphase.

Animals↗
PubMed1987

[Clinical application of carcinoembryonic antigen (CEA) monoclonal antibodies (McAbs)].

CEA McAbs, recognizing three different epitopes on CEA molecules, were used to measure serum CEA level in cancer patients by enzyme-immunoassay (EIA). The results, as compared with those using polyclonal antibodies, indicated that the positive rate was higher while the false positivity was lower. Immunohistochemistry of tumour sections showed that the CEA McAbs are bonded to 80-90% of gastrointestinal cancers. Although the normal colon epithelium occasionally reacted with CEA McAbs, other normal tissues did not. After in vivo administration of radio-labeled CEA McAbs to nude mice xenograft with human colon cancer, the radio-isotope was found to be concentrated preferentially in the tumour. The ratio of tumour and normal tissue was 3.6-11.8 after 48 hours following administration. Thus, the CEA McAbs can be used clinically not only for serum CEA determination but also for diagnostic imaging.

Antibodies, Monoclonal↗
PubMed1983

Study of inhibitory effect of amygdaloid stimulation on auditory response of medial geniculate body (MGB) and analysis of transmissive pathway of the said effect.

Experiments performed on 103 rabbits immobilized with Flaxedil, and the recording of the electrical discharges of single MGB neuron caused by clicks, burst or sustained tone showed marked inhibition of the reaction of 47 out of 75 (62.7%) MGB units responding to sound stimuli, when the amygdaloid complex was stimulated. The latent period of such an inhibitory effect was 5-12 msec and its duration about 2-13 msec. Evoked responses with the latency of 1-2 msec for the stimulation of medial, central and lateral nuclei of amygdala could be recorded from the temporal and parietal cortex. The largest response was recorded from Woolsey's AI area of the temporal cortex. Stimulation of the Woolsey's AI auditory area could also result in a distinct inhibition of the spontaneous as well as the evoked discharges of MGB neurons in response to sound stimulation. Moreover, application of 1% procaine to the surface of auditory cortex could block the inhibitory effect of the amygdala on the MGB neurons. Based on the facts mentioned above, the authors have reason to believe that the inhibitory effect of the amygdaloid complex on the activity of MGB units might be transmitted via the amygdala-auditory cortex-MGB circuit. The biological significance of such an suppressive effect has been discussed.

Acoustic Stimulation↗