Biomedical subjects
C Y Yang
Publications and source records attributed to C Y Yang.
The action of parathyroid hormone on bone metabolism may be regulated by endogenously synthesized prostaglandin E2.
Explore the source record for details and available documents.
The chromosome translocation (11;14)(p13;q11) associated with T-cell acute lymphocytic leukemia: an 11p13 breakpoint cluster region.
The translocation (11;14)(p13;q11) was observed in karyotypes of leukemic cells from a 3-year-old boy with T-cell acute lymphocytic leukemia (T-ALL). Since this translocation is a recurrent marker of T-ALL, we undertook to investigate its mode of formation and role in leukemogenesis. The cytogenetic breakpoint on chromosome 14 occurs in 14q11, the same band wherein lies the T-cell receptor alpha/delta chain gene; and Southern hybridization analysis of peripheral blood and bone marrow DNA uncovered a tumor-specific rearrangement in the D delta-J delta region of this locus. DNA encompassing the rearrangement was isolated by molecular cloning, and further analysis revealed it to be the t(11;14)(p13;q11) junction. Nucleotide sequence determination of the junction indicates that the 14q11 breakpoint occurs immediately adjacent to the D delta 2 gene segment. Hence, the translocation arose as an aberrant rearrangement between the downstream recombination signal of D delta 2 and a pseudo recombination signal adjacent to the chromosome 11 breakpoint. Finally, comparison of the breakpoint in band 11p13 with those of other translocations (11;14)(p13;q11) identified a breakpoint cluster region of approximately 1.2 kilobase-pairs (kb), alterations of which may promote the development of T-ALL.
Pathophysiological relevance of prostaglandins in oral diseases.
Prostaglandins (PGs) are a group of 20-carbon unsaturated fatty acids derived from arachidonic acid, one of the key components of phospholipids in animal cell membranes. Although PGs were originally named and discovered in the prostate gland of man and sheep, current evidence suggests that PGs are synthesized by nearly all mammalian cells. The biological and pathological functions of these compounds are extremely varied and complicated. This paper will first review the biosynthesis, metabolism, biological and pathological effects, and clinical applications of these naturally occurring substances in living organisms. The possibility that these compounds may mediate the pathophysiological functions of oral diseases is then discussed in detail. Prostaglandins have been demonstrated to be related to the pathogenesis of periodontal diseases, dental cyst, pulpal and periapical pathologies, wound healing, tooth movement, and oral cancers. Studies have shown that anti-inflammatory drugs block the synthesis of PGs, and antagonists competitively inhibit the action of these compounds in the body. The application of PG inhibitors and PG antagonists or analogues for prevention and treatment of oral diseases might thus be a promising research field for future development.
Prevention of postlaminectomy membrane: experimental and clinical observations.
An animal experimental study was performed to investigate the prevention of scar formation after laminectomy by applying Gelfoam, a free-fat graft and steroids as interposing material between the dura and muscles. There were 52 adult guinea pigs equally divided into four groups. They were sacrificed 2 weeks, 4 weeks and 12 weeks respectively after surgery. In the control group, there was young fibrous tissue at 2 weeks, which became more mature at 4 weeks. At 12 weeks, it became mature with varying thickness and canal extension. In the steroid group, it showed the same picture as the control group. In the Gelfoam group, there was foreign body reaction with disintegration of Gelfoam at 2 to 4 weeks. At 12 weeks, however in the free-fat graft group, viable fat graft could be seen at the laminectomy site with little fibrous tissue overlying the dura. In the clinical part, from September 1981 to September 1984, one of the authors (PQC) performed 100 laminectomies on patients with various causes of low back pain. A piece of free subcutaneous fat was laid on dura before wound closure. At follow-up, there was no adverse effect pertaining to its application. Most patients had considerable pain relief after the surgery. From the above observation, we believe that a free-fat graft is a simple and effective way to prevent postlaminectomy membrane. Steroids and Gelfoam do not have such advantage.
Grading of soft tissue sarcomas: necrosis as a determinant of survival.
All cases of sarcomas of soft tissue occurring in males age 20-79 in Western Washington from 1981 to 1984 were studied with respect to the influence of multiple clinical, gross, and histologic parameters in predicting survival. Among histologic parameters studied, a strong and statistically significant association of necrosis of more than 15% of the tumor with death was observed. This effect was seen even when controlling for the influence of histology, site, stage of disease, and other factors. It is concluded that necrosis can serve as a prognostically relevant criterion for separating aggressive (nongrade 1) soft tissue sarcomas into intermediate grade (grade 2) and high grade (grade 3) tumors.
[Preliminary pathological observation on bone injury after inhalation of trifluoromethyl hypofluoride in rats].
This paper reports the relation between fluoride contents and pathologic changes of skeletal system in Wistar rats after inhalation of organofluoride compound-trifluoromethyl hypofluoride. The trifluoromethyl hypofluoride (CF3OF), purity greater than 95%, used in this study was produced and provided by the Chenguang Chemical Industrial Institute. Twenty-four Wistar rats, weighing between 200 and 250g, were divided into three groups: a control group and two test groups. They were exposure to the trifluoromethyl hypofluoride gas at a dosage of 0, 0.067 and 0.1 ppm respectively, in 1 m3 Plexiglass chamber, two hours a day, five days a week. The results showed that the fluoride levels of ilia in 0.067 and 0.1 ppm group rats were significantly higher than those in the control group (P less than 0.05). The osteogenic effect of CF3OF was confirmed by the histopathological examination of the skeletal tissues. The lesions were also mainly limited to the 0.1 ppm CF3OF group. A very marked osteogenic reaction was found in the periosteum and Haversian canals of ilia in the rats including focal active periosteous osteoblastic proliferations and bone or osteoid tissues forming with a little osteoclastic reactions. for 23 weeks.
Recurrent Dieulafoy's lesion after surgical ligation.
Explore the source record for details and available documents.
Colocalization of GABA and glycine immunoreactivities in a subset of retinal neurons in tiger salamander.
Alternate serial 1 micron Durcupan resin sections of tiger salamander retina were stained with antisera against GABA and glycine using postembed immunocytochemical techniques. Although the vast majority of neurons were labeled by either GABA or glycine antiserum, a small percentage of presumed amacrine cells in the inner nuclear layer and cells in the ganglion cell layer were clearly labeled by both antisera, indicative of colocalization of endogenous GABA and glycine. Although there is a greater than 90% chance that a labeled cell will be clearly labeled for either GABA or glycine immunoreactivity, the possibility for cotransmission of two inhibitory transmitters must be considered for a small percentage of these retinal neurons.
Localization of putative GABAergic neurons in the larval tiger salamander retina by immunocytochemical and autoradiographic methods.
Putative GABAergic neurons in the larval tiger salamander retina were localized by a comparative analysis of glutamate decarboxylase immunoreactivity (GAD-IR), GABA-like immunoreactivity (GABA-IR), and high-affinity 3H-GABA uptake at the light microscopical level. Preliminary data showed that all GAD-IR neurons were double labeled for GABA-IR. However, because the weak somatic labeling with GAD-IR, we could not determine if the converse were true. Neurons commonly labeled with GABA-IR and 3H-GABA uptake include horizontal cells, type I (outer) and type II (inner) bipolar cells, type I (inner) and type II (outer) amacrine cells, and cell bodies in the ganglion cell layer (GCL). In addition, interplexiform cells were identified with GABA-IR. The presence of GABA-IR ganglion cells was indicated by GABA-IR fibers in the optic fiber layer and optic nerve as well as by a GABA-IR cell in the GCL that included a labeled axon. The percentage of labeled somas in the inner nuclear layer (INL) compared to all cells in each layer was similar for the two methods: 30% in INL 1 (outer layer of somas), 15% in INL 2 (middle layer), 43-52% in INL 3 (inner layer), and about 21-26% in the GCL. Labeled processes were found in three bands in the inner plexiform layer, with the densest band located in the most proximal part. Postembedding labeling of 1-micron Durcupan resin sections for GABA-IR showed the same general pattern as obtained with 10-microns cryostat sections, with additional staining, however, of type II (inner) bipolar cell Landolt's clubs. Extensive colocalization of labeling was indicated, and we conclude that GABA-IR can serve as a valid and reliable marker for GABA-containing neurons in this retina and suggest that GABA serves as a transmitter for horizontal cells, several types of amacrine cell, a type of interplexiform cell, and perhaps a small percentage of type I and type II bipolar cells and ganglion cells.
Complete amino acid sequence of the thioesterase domain of chicken liver fatty acid synthase.
The complete amino acid sequence of thioesterase domain of chicken liver fatty acid synthase has been determined by sequencing peptides produced by trypsin, Staphylococcus aureus V8 protease, and cyanogen bromide cleavage. The thioesterase domain consists of 300 amino acid residues. All of the tryptic peptides of the thioesterase domain were isolated and sequenced, except the segment covered from position 109 to position 124. Peptides resulting from digestion by Staphylococcus aureus V8 protease and cyanogen bromide cleavage filled the missing part and overlapped the complete sequence of the entire thioesterase domain. The NH2 terminus of the thioesterase domain was determined to be lysine by sequencing the whole domain up to 20 residues while the COOH terminus was identified as serine through carboxyl peptidase Y cleavage. The active site of the thioesterase domain of chicken fatty acid synthase was suggested to be the serine on position 101 according to its homology with other serine-type esterases and proteases which have a common structure of -Gly-X-Ser-Y-Gly- with the variable amino acids X and Y disrupting the homology.
Primary sequence mapping of human apolipoprotein B-100 epitopes. Comparisons of trypsin accessibility and immunoreactivity and implication for apoB conformation.
Differential trypsin-accessibility and monoclonal antibodies (Mabs) to human apolipoprotein (apo) B-100 are both important tools for probing apoB structure and conformation on low-density lipoproteins (LDL). In this study, we have mapped greater than 80% of the C-terminal region (720 residues) of LDL apoB-100 using trypsin digestion. Our results extend our previous data [Yang et al. (1986) Nature (Lond.) 323, 738-742] confirming that the C-terminal region of about 420 residues of apoB-100 is largely inaccessible to trypsin, whereas the part just preceding this region has interspersed trypsin-accessible and inaccessible peptides. We have determined the amino acid sequence of specific apoB-100 peptides containing epitopes recognized by four separate Mabs: two epitopes have been mapped to within 20 residues, one has been mapped to 36 residues, and the last to 80 residues. We used polyclonal antisera to identify 16 overlapping clones of varying lengths of apoB-100 cDNAs extending from the C-terminus of apoB-100 cloned in the expression vector, lambda gt11. These clones were then tested against individual Mabs. By nucleotide sequence analysis of overlapping clones that show differential reactivities to different Mabs, we have mapped the individual epitopes of each Mab to within about 50-150 amino acid residues predicted from the DNA sequences. Confirmation and further fine mapping were accomplished by competition for LDL binding using partially purified fusion proteins and chemically synthesized oligopeptides. Two epitopes (Mabs 7 and 22) were mapped to the C-terminal 20 amino acids of apoB-100, one (Mab 16) to residues 4154-4189, and another (Mab 20) to residues 3926-4005. Mab 16 precipitates more than 80% of LDL particles. Mab 20 precipitates only denatured apoB but not native LDL apoB [Milne et al. (1987) Mol. Immunol. 24, 435]. Mabs 7 and 22 are unique in that they precipitate LDL apoB modified by storage much better than freshly isolated LDL-apoB. Although epitope expression and trypsin-accessibility represent two useful probes for the study of protein conformation, there was no obvious correlation between these two parameters when applied to LDL apoB for the antibodies we have examined.
Light microscopic localization of putative glycinergic neurons in the larval tiger salamander retina by immunocytochemical and autoradiographical methods.
Putative glycinergic neurons in the larval tiger salamander retina were localized by a comparative analysis of high affinity 3H-glycine uptake and glycine-like immunoreactivity (Gly-IR) at the light microscopic level. Commonly labeled neurons include at least three types of amacrine cell (Type IAd, Type IAb, Type IIAd; distinguished by soma location and dendritic ramification), cell bodies in the ganglion cell layer (GCL), and rarely observed Type II (inner) bipolar cells. With the increased resolution provided by Gly-IR, we identified a Type IAa amacrine cell, two types of Type IIAd amacrine cells, and Gly-IR interplexiform cells. Gly-IR axons in longitudinal sections of the optic nerve indicate the presence of Gly-IR ganglion cells. The percentage of labeled somas in the inner nuclear layer (INL) compared to all cells in each layer was similar for the two methods: 30-40% in INL 2 (middle layer of somas), 30-40% in INL 3 (inner layer of somas), and about 5% in the GCL. Labeled processes were found throughout the full thickness of the inner plexiform layer (IPL), but with a much denser band in the proximal half (sublamina b). The only major difference between the two methods (3H-glycine uptake vs. Gly-IR) was that Type I (outer) bipolar cells were labeled only by 3H-glycine uptake; these cells were more lightly labeled with silver grains than cell bodies in either INL 2 or INL 3. Postembed labeling of 1 micron Durcupan plastic sections for Gly-IR showed the same pattern, but with much higher resolution, as obtained with 10 micron cryostat sections. This study indicates extensive colocalization of labeling by both probes in INL 2, INL 3, the IPL, and the GCL. We conclude that Gly-IR can serve as a valid and reliable marker for glycine-containing neurons in this retina and suggest that glycine serves as a transmitter for several morphologically distinct types of amacrine cell, an interplexiform cell, and perhaps a small percentage of Type II bipolar cells and ganglion cells.
Changes in pancreatic enzyme specific activities of rats fed a high-fructose, low-copper diet.
This study describes the progressive changes in exocrine pancreatic enzyme specific activities from rats provided with a diet containing either 62% starch (S) or fructose (F) with 6.0 ppm copper (+Cu) or 0.6 ppm (-Cu) from 21 to 61 days of age. Copper-deficient rats had significantly reduced pancreatic weight and DNA, RNA, protein and copper content and superoxide dismutase (SOD) activity after consuming diet for 39 days. These reductions were far more severe in F-Cu than in S-Cu rats. Copper deficiency significantly reduced pancreatic amylase and lipase specific activities, but the effect was more severe in the F-Cu dietary group. Chymotrypsinogen and trypsinogen specific activities were reduced only in the F-Cu dietary group and the CHO x Cu interaction was significant. High dietary fructose and low dietary copper in combination interact to produce severe reductions in pancreatic amylase, lipase, chymotrypsinogen, and trypsinogen specific activities which could not be explained by either copper deficiency or by an increase in dietary fructose alone.
Preparation and characterization of monoclonal antibodies to cephalexin-synthesizing enzyme from Acetobacter turbidans.
Eleven monoclonal antibodies against the cephalexin-synthesizing enzyme have been constructed and primarily characterized. These antibodies are all IgG1 type, with medium affinity, and with no enzyme-inhibition effect. They will be utilized as immunoadsorbents to purify their corresponding antigen, the enzyme, in one step.
Exocrine pancreatic enzyme activities and mineral concentrations in SHR/N-corpulent (cp) male rats.
Exocrine pancreatic enzyme activities and mineral concentrations were measured in a newly developed congenic strain of corpulent rat (SHR/N-cp). Approximately 4- to 5-wk-old corpulent (cp/cp) and lean (+/?) male rats consumed a diet containing 54% carbohydrate as either cooked cornstarch or 27% cooked cornstarch and 27% fructose for 9.5 mo. After consuming the diet for 3 mo, corpulent rats were hyperinsulinemic, hyperlipidemic and exhibited glycosuria. After consuming the diet for 9.5 mo corpulent rats were twofold heavier and pancreatic weight was 77% that of their lean littermates. Corpulent rats that consumed starch exhibited lower total pancreatic protein with no significant change in total DNA and RNA. In the corpulent rat, both lipase- and chymotrypsinogen-specific activities and both the specific activities and the content of amylase or trypsinogen were lower than those of lean littermates. Fructose consumption resulted in lower pancreatic copper and iron concentrations, and zinc concentration was elevated in corpulent rats. This study suggests that the SHR/N-corpulent rat may be a useful model for studying exocrine pancreatic function in insulin-independent diabetes.
Isolation and culture of two cell populations from chick calvaria by density gradient: prostaglandin synthesis by the cells in culture and coculture.
In previous studies we demonstrated that PTH stimulates production of prostaglandin E2 (PGE2) by intact chick calvaria. In the present series of experiments, two cell populations were isolated from chick calvaria by centrifugation on a 25%/55% Percoll gradient. Cells harvested from the upper band of the Percoll gradient (designated F-1) appeared large and spindle-shaped in culture. Cells harvested from the lower band of the Percoll gradient (designated F-2) were relatively small and polygonal-shaped. Both cell populations required fetal bovine serum (FBS) for attachment and proliferation. In the presence of FBS the cells formed multilayers, but they formed confluent monolayers in the presence of heat-inactivated FBS. The pattern of cAMP responses to different effectors and biochemical determinations for alkaline and acid phosphatase suggests that the F-2 fraction consists primarily of osteoblasts. No cells with osteoclastic patterns appeared in either fraction. Both cell types synthesized predominantly PGD2. PGE2 was also produced, however, in considerably smaller quantities. PG production in the presence of ionophore A23187 (1 microM) or arachidonate (10 microM) increased significantly when the F-1 and F-2 cells were cocultured at a 1:1 ratio. These results suggest that cell to cell or cell to matrix interactions normally present in intact bone influence PG synthesis.
[Acute hepatitis in an uremic patient following isoflurane anesthesia].
Explore the source record for details and available documents.