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Biomedical subjects

G Yang

Publications and source records attributed to G Yang.

At least 505 records · Page 28Linked to original sources
PubMed1985

An electron microscopic study of terminals of rapidly adapting mechanoreceptive afferent fibers in the cat spinal cord.

The intra-axonal horseradish peroxidase technique was used to examine the central terminals of 7 A beta primary afferent fibers from rapidly adapting (RA) mechanoreceptors in the glabrous skin of the cat's hindpaw. At the light microscopic level, labelled collaterals were seen to bear occasional boutonlike swellings, mostly (75-82%) of the en passant type. These swellings were distributed more or less uniformly from lamina III to a dorsal part of lamina VI in the dorsal horn, over a maximum longitudinal extent of about 4 mm. At the electron microscopic level, we observed that labelled boutons of RA afferent fibers were 1.0 to 3.3 micrometers in longest sectional dimension, and contained clear, round synaptic vesicles. They frequently formed asymmetric axospinous and axodendritic synapses and commonly appeared to receive contacts from unlabelled structures containing flattened or pleomorphic vesicles plus occasional large dense-cored vesicles. The examination of synaptic connectivity over the entire surface of individual boutons indicated that RA afferent boutons each made contacts with an average of one spine and one dendrite and, in addition, appeared to be postsynaptic to an average of two unlabelled vesicle-containing structures. This synaptic organization was, in general, more complex than that we had seen previously in Pacinian corpuscle (PC) and slowly adapting (SA) type I mechanoreceptive afferent fibers. Our findings indicate that RA, SA, and PC afferent terminals, while displaying some differential synaptic organizations, have many morphological and synaptological characteristics in common. These afferent terminals, in turn, seem to be generally distinguishable from the terminals of muscle spindle Ia afferents or unmyelinated primary afferents.

Animals↗
PubMed1984

Organization of the infraorbital nerve in rat: a quantitative electron microscopic study.

The normal organization of the rat's infraorbital (IO) nerve was studied using conventional electron microscopic (EM) methods. Just caudal to the infraorbital foramen, at the level of the anterior superior alveolar foramen, the nerve was composed of 18-25 fascicles which ranged from 575 to 87,923 micron2 in cross-sectional area. Complete axon counts from thin sections taken at this level demonstrated that the IO nerve contained an average of 19,740 (S.D. = 2054) myelinated and 13,319 (S.D. = 1159) unmyelinated axons. The average diameter (including the myelin sheath) for medullated fibers was 4.42 micron (S.D. = 1.76) and that for unmyelinated axons was 0.60 micron (S.D. = 0.16). The fiber diameter distributions for both myelinated and unmyelinated axons were essentially unimodal.

Animals↗
PubMed1983

An electron microscopic study of primary afferent terminals from slowly adapting type I receptors in the cat.

Primary afferent fibers transmitting impulses from slowly adapting (SA) Type I receptors in the glabrous skin of the hind paw of the cat were injected intraaxonally in the spinal cord with horseradish peroxidase (HRP). At the light microscopic level, terminal arborizations were observed in the medial dorsal horn extending up to 6 mm rostrocaudally in and near the seventh lumbar segment. Boutonlike swellings labelled with HRP were distributed in clusters in Rexed's laminae III-VI. There was a tendency for the most dorsal clusters from an individual fiber to be located rostrally and for the most ventral clusters to be located caudally. At the electron microscopic level, a combination of morphometric analysis and serial reconstruction revealed the following: (1) All the boutons labelled with HRP contained predominantly clear, round synaptic vesicles, 40-50 nm in diameter. (2) Labelled boutons (n = 75) had cross-sectional longest dimensions of 1.72 +/- 0.53 micron (Mean +/- S.D.), perimeters of 4.95 +/- 1.52 micron, and areas of 1.18 +/- 0.59 micron 2. Their shapes in section varied from rounded to elongated forms. (3) The sizes of labelled boutons decreased significantly and linearly with depth from lamina IV to VI. The shapes of the bouton cross sections also became rounder with depth in the dorsal horn. (4) About 72% of synaptic contacts associated with HRP-filled boutons were with dendritic spines and shafts; most of these synapses were of the asymmetric type. (5) The remainder (28%) of the appositions were synapselike contacts between labelled boutons and unlabelled structures containing flattened or pleomorphic vesicles, and occasional dense-cored vesicles. (6) We observed no unequivocal axosomatic contacts made by labelled boutons. (7) The lengths of synaptic appositions with dendritic spines (0.46 +/- 0.20 micron) or with dendritic shafts (0.51 +/- 0.18 micron) were significantly greater than the synapselike contacts with vesicle-containing unlabelled structures (0.29 +/- 0.09 micron). (8) Complex neuropilar organization was occasionally seen with labelled boutons as central elements, although simpler organizations were much more common. In summary, HRP-labelled fibers ended predominantly in boutons containing clear, round vesicles forming axospinous and axodendritic synapses.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Reduction of interference by specific IgG with a modified microtiter solid-phase radioimmunoassay to measure honeybee venom IgE.

By means of monoclonal mouse anti-human IgE antibody, the microtiter solid-phase radioimmunoassay (MSPRIA) was modified to measure honeybee venom (HBV) IgE. HBV IgG was measured by MSPRIA(G) using affinity column purified goat anti-human IgG antibody and correlated with results obtained with staphylococcal protein A-SPRIA. Nonlinear specific IgE dilution curves were associated with high HBV IgG content. By serial transfer and assay of the supernatant, the interference of IgE by specific IgG could be reduced. The degree of interference was correlated with the specific IgG content. The principle of serial supernatant transfer and assay was applied to the standardization of reference HBV IgE serum, and the quantitation of HBV IgE contents in patients and controls. HBV IgE levels in patients allergic to honeybee stings correlated with the skin-test endpoint titrations. While 75% of the allergic patients were skin-test positive, 83% of them were IgE positive by the MSPRIA and 67% were IgE positive by the RAST.

Antibodies, Anti-Idiotypic↗
PubMed1983

Enteral administration of agar as an effective adjunct to phototherapy of neonatal hyperbilirubinemia.

Phototherapy increases the biliary excretion of unconjugated bilirubin. In this form, bilirubin would be subject to enterohepatic circulation, and the true efficacy of phototherapy would be blunted. We tested the hypothesis that sequestration of lumenal unconjugated bilirubin by enteral agar administration would enhance the efficacy of phototherapy in jaundiced infants. Fifty-two infants were studied, 21 control and 31 agar-supplemented. The birth weights, sex distribution, and postnatal age at onset of phototherapy did not differ between the two groups of infants; pre- and post-phototherapy bilirubin concentrations also did not differ between the groups. The bile acid concentrations and bilirubin saturation indices were also similar. The rate of declination of the plasma bilirubin concentrations after 24 h of phototherapy was greater and significantly more uniform in the agar-supplemented infants (-1.59 +/- 2.3 versus -2.51 +/- 1.44). Stool frequencies were greater in control infants (5.5 versus 4.3 per 24 h) whereas fecal bilirubin excretions were greater in agar-supplemented infants during the second day of phototherapy (1.32 versus 3.29 mg . kg-1 . 24 h-1). Agar supplementation reduced the duration of phototherapy by 23% (37.6 +/- 3.2 versus 48.1 +/- 5.0 h).

Agar↗
PubMed1983

Honey bee venom specific immunoglobulin G4 in honey bee sting allergic patients and bee keepers.

Honey bee venom (HBV) IgG4 antibody was studied in bee keepers and honey bee sting allergic patients on immunotherapy using mouse monoclonal anti-human IgG4 antibody in a modified microtiter solid phase radioimmunoassay (MSPIRA). The mean HBV IgG4 in bee keepers was 31 units/ml. In patients the mean HBV IgG4 pre- and post-immunotherapy were 2.9 and 11.6 units/ml, respectively, representing a mean rise of 7.3-fold as compared to a rise of 1.6-fold for total HBV IgG. The mean HBV IgG level in bee keepers was 14 micrograms/ml which was not significantly different from the mean level of 17 micrograms/ml in allergic patients at diagnosis. The percentage interference of HBV IgE detection in vitro correlated with HBV IgG but not with HBV IgG4. On the other hand, there was an inverse relationship between serum HBV IgE and HBV IgG4 levels while none was found for HBV IgE and IgG.

Antibodies, Anti-Idiotypic↗
PubMed1983

Studies of rhenium carboxylates as antitumor agents. Part II. Antitumor studies of bis (mu-propionato) diaquotetrabromodirhenium (III) in tumor-bearing mice.

The neutral, dimeric complexes of rhenium, bis (mu-carboxalato)-diaquotetrahalodirhenium (III) (carboxalato = acetato, propionato, or butyrato and halo = chloro or bromo), were synthesized and survival studies were done on mice bearing P-388 leukemia or B-16 melanoma. The complex bis (mu-propionato) diaquotetrabromodirhenium (III) proved to be the most effective in increasing the life span of the mice. The complex showed some activity against B-16, but virtually none against P-388. The complexes are all quite non-toxic.

Animals↗
PubMedDate not supplied

The anisotropic Hooke's law for cancellous bone and wood.

A method of data analysis for a set of elastic constant measurements is applied to data bases for wood and cancellous bone. For these materials the identification of the type of elastic symmetry is complicated by the variable composition of the material. The data analysis method permits the identification of the type of elastic symmetry to be accomplished independent of the examination of the variable composition. This method of analysis may be applied to any set of elastic constant measurements, but is illustrated here by application to hardwoods and softwoods, and to an extraordinary data base of cancellous bone elastic constants. The solid volume fraction or bulk density is the compositional variable for the elastic constants of these natural materials. The final results are the solid volume fraction dependent orthotropic Hooke's law for cancellous bone and a bulk density dependent one for hardwoods and softwoods.

Anisotropy↗
PubMedDate not supplied

Cooperative therapeutic effects of androgen ablation and adenovirus-mediated herpes simplex virus thymidine kinase gene and ganciclovir therapy in experimental prostate cancer.

Adenovirus-mediated transduction of the herpes simplex thymidine kinase gene (HSV-tk) in conjunction with ganciclovir (GCV) has been shown to result in significant growth suppression and to enhance survival in a model of mouse prostate cancer. However, this therapeutic activity is not sustained, because in most cases tumors eventually regrow and ultimately cause the death of the host. Androgen ablation, an inducer of apoptosis in prostate cells which is used widely as palliative therapy in patients with prostate cancer, was combined with HSV-tk plus GCV using an androgen-sensitive mouse prostate cancer cell line. The combination of castration and HSV-tk plus GCV led to markedly enhanced tumor growth suppression in both subcutaneous and orthotopic models compared with either treatment alone and resulted in an enhanced survival in which combination-treated animals lived twice as long as controls in the subcutaneous model and over 50% longer than controls in the orthotopic model. Further analysis of apoptotic activity demonstrated high levels of apoptosis only in combined androgen ablation and HSV-tk plus GCV-treated tumors after 14 days of growth in an androgen-depleted environment and 8 days after HSV-tk plus GCV therapy. At this time, the apoptotic index, but not the percent of necrotic tissue, was significantly higher for combination therapy-treated tumors relative to control-treated tumors or either treatment alone. These data indicate that the therapeutic effects of androgen ablation and HSV-tk plus GCV are cooperative and that increased apoptosis may, in part, underlie these activities.

Adenoviridae↗
PubMedDate not supplied

New variations in intron 4 of growth hormone gene in Chinese native chickens.

Polymorphism in intron 4 of chicken growth hormone (cGH) gene was studied in 20 Chinese native chicken populations and broiler or layer populations. A total of eight restriction digestion profiles were identified in intron 4 and confirmed by sequencing. Among 20 populations, there were distinctively different allele numbers and frequencies of intron 4 restriction fragment length polymorphisms (RFLPs) between Chinese native chickens and broilers or layers. Two new alleles, allele D and allele E, were identified in Taihe Silkies. Allele D was also identified in other Chinese native breeds and a 50 bp fragment deletion was identified in allele E.

Animals↗
PubMedDate not supplied

Angiotensin II--an important stress hormone.

Angiotensin II (Ang II) is an important stress hormone. Circulating and tissue Ang II are significantly increased in both acutely and chronically stressed animals. In humans, the plasma Ang II content increases markedly after sprinting, as does cortisol. The present paper reviews recent studies with special reference to the correlation between the renin-angiotensin system (RAS) and the hypothalamus-pituitary-adrenal cortex system and sympathetic-adrenal medulla system during stress. We would like to suggest that in the stress response, Ang II is not only a stress hormone to various peripheral organs, but is also a notable factor in initiating the systemic stress response from central to peripheral tissues. The RAS is therefore a stress hormone response system similar to the hypothalamus-pituitary-adrenal cortex system and the sympathetic-adrenal medulla system.

Angiotensin II↗
PubMedDate not supplied

Changes in circulating and tissue angiotensin II during acute and chronic stress.

Changes of angiotensin II and cAMP in plasma, brain tissue, adrenal gland and cardiovascular tissue during the acute and chronic stress were studied in rats. The acute stress group was subjected to compulsive cold water swimming for 20 min, while the chronic stress group was exposed to an ambient temperature of 4-8 degrees C for 5 days. The results indicated that plasma angiotensin II levels were significantly increased in both stress groups, reaching up to 900% and 134% of the control in the acute and chronic groups, respectively. Angiotensin II contents in the anterior hypothalamus, medulla oblongata, myocardium, vasculature and adrenals were also elevated in both groups. With the exception of the adrenals, the contents of tissue angiotensin II in the chronic stress animals were significantly higher than those of the acute stress animals. In contrast, cAMP levels in plasma and tissue (hypothalamus and adrenals) and corticosterone levels in plasma in the acute stress group were all higher than those in the chronic stress animals, although the levels of the latter group were also increased compared with the control group. These results suggest that circulating and tissue angiotensin II may play an important role in the acute and chronic stress responses and that angiotensin II should be classified as a stress hormone.

Adrenal Glands↗