Biomedical subjects
Publications and source records attributed to G Gong.
The spectra of radicle chromosome of broad bean, marrow cell chromosome and marrow cell micro-nucleus of small white mouse were measured within the range of visible light by microspectrum technique. The differences among the spectra were found.
We investigate the familial risks of cancers of the breast and ovary, using data pooled from three population-based case-control studies of ovarian cancer that were conducted in the United States. We base estimates of the frequency of mutations of BRCA1 (and possibly other genes) on the reported occurrence of breast cancer and ovarian cancer in the mothers and sisters of 922 women with incident ovarian cancer (cases) and in 922 women with no history of ovarian cancer (controls). Segregation analysis and goodness-of-fit testing of genetic models suggest that rare mutations (frequency .0014; 95% confidence interval .0002-.011) account for all the observed aggregation of breast cancer and ovarian cancer in these families. The estimated risk of breast cancer by age 80 years is 73.5% in mutation carriers and 6.8% in noncarriers. The corresponding estimates for ovarian cancer are 27.8% in carriers and 1.8% in noncarriers. For cancer risk in carriers, these estimates are lower than those obtained from families selected for high cancer prevalence. The estimated proportion of all U.S. cancer diagnoses, by age 80 years, that are due to germ-line BRCA1 mutations is 3.0% for breast cancer and 4.4% for ovarian cancer. Aggregation of breast cancer and ovarian cancer was less evident in the families of 169 cases with borderline ovarian cancers than in the families of cases with invasive cancers. Familial aggregation did not differ by the ethnicity of the probands, although the number of non-White and Hispanic cases (N = 99) was sparse.
Familial juvenile polyposis has been known to have malignant potential, but their genetic relation to familial adenomatous polyposis has not been proven yet. Two young brothers with intermittent rectal bleeding revealed multiple juvenile polyposis. Their father had a history of rectal cancer with multiple colonic polyps. Four frequent exons of APC gene mutation were tested from these patients' white blood cells by polyacrylamide gel electrophoresis and sequencing. The 21-yr-old brother had a missense mutation (GAA-->GGA) at codon 1309, whereas the 18-yr-old brother showed a missense mutation (ATA-->GTA) at codon 1304 in exon 15 of APC gene. Three of four first-degree relatives were affected with familial juvenile polyposis, familial juvenile polyposis with adenomatous change, and rectal cancer with multiple polyps. The APC gene mutation of familial juvenile polyposis in this case suggests a genetic relationship with familial adenomatous polyposis.
Male Dahl salt-sensitive hypertensive (S) rats develop hypertension faster than females. We measured renal alpha2-adrenergic receptor density of inbred Dahl salt-sensitive (SS/JR) and salt-resistant (SR/JR) rats, using [3H]-rauwolscine saturation binding studies. Male and female SS/JR rats were gonadectomized or sham-operated at 6 weeks of age and fed a high salt diet for 4 weeks. Additional intact SS/JR and SR/JR rats of both sexes were fed the high salt diet for a longer period of time (7 weeks instead of 4 weeks). Both blood pressure and renal alpha2-adrenergic receptor density were significantly higher in male than female SS/JR rats on high salt diet for 4 weeks. Gonadectomy did not change blood pressure nor did it change renal alpha2-adrenergic receptor density measured at the 4th week of high salt feeding in either male or female SS/JR rats. When the SS/JR rats were fed high salt diet for a longer period (for 7 weeks), blood pressure of female SS/JR reached the level of males, but the density of renal alpha2-adrenergic receptors was still significantly lower than that of males. Both renal alpha2-adrenergic receptor density and blood pressure were higher in male than female SR/JR. We conclude that higher blood pressure in male Dahl SS/JR and SR/JR rats is associated with higher renal alpha2-adrenergic receptor density compared with their female counterparts.
A method for determination of trace lead in blood with complex catlysis polarography was develop. The peak potential of lead is -0.54 V in the system of hydrochloric acidpotassium iodide-vanadium (IV)-ethanol-ascorbic acid. There is good linelar relationship between peak current and lead concentration in the range of 0-1.0 microgram/3 ml. The recoveries of spiked samples ranged from 76.0% to 105.0% and the average recovery was 91.0% with RSD of 3.6% to 7.0%. The detection limit was 45 micrograms/L. The blood samples of 24 normal people and 6 workers with occupational exposure to lead were measured and the results were concordant with the clinical diagnoses. The proposed method is simple, rapid, sensitive and reliable. It is suitable for determination of trace lead in blood.
We determined vitamin D receptor (VDR) gene alleles (based on the BsmI restriction site polymorphism), duodenal mucosal receptor density, bone mass at spine and total body, and body size in 32 healthy premenopausal females. While we found no relationship between allele and receptor density in duodenal mucosa, bone mineral content (BMC) at both spine and total body was significantly associated with VDR gene alleles. BMC was highest for the bb allele, lowest for BB, and intermediate for Bb. A similar association was noted between allele and body size variables, particularly weight. When BMC was adjusted for body weight, the association with VDR polymorphism disappeared. The VDR gene polymorphism may be affecting bone mass not through classical nutritional mechanisms (e.g., intestinal calcium absorption), but through an influence on body size.
RATIONALE AND OBJECTIVES: To correlate magnetic resonance (MR) signal enhancement with pathophysiologic changes occurring during ischemia and reperfusion in evaluation of myocardial infarction in cats. METHODS: Seven cats were subjected to 150 minutes of occlusion of the left anterior descending coronary artery followed by 90 minutes of reperfusion. Gadolinium (Gd) diethylenetriaminepentaacetic acid-polylysine (molecular weight [mw] = 40 to 50 kd, DP230) contrast-enhanced MR images were acquired with coinjection of poly-L-lysine-fluorescein isothiocyanate (mW = 40 to 50 kd, DP219) as a fluorescent tracer molecule of the contrast agent. Signal intensities on the MR images and fluorescence activities on the resected cardiac specimens were measured. Pathologic examinations by electron and light microscopes and 2,3,5-triphenyltetrazolium chloride histochemical staining were performed on the specimens. RESULTS: Magnetic resonance signal intensity was lower in the center (3.49 +/- 0.36) than in the periphery (4.71 +/- 0.89) of the enhanced area. Fluorescence activities were absent in the normal myocardium; they were scant as nonspecific discrete dots in the center and numerous as specific interstitial distribution in the periphery of the ischemic myocardium. Electron and light microscopic examinations showed severely damaged ultrastructures of the center and moderately distorted ultrastructures of the periphery. CONCLUSIONS: The center of the MR signal-enhanced area is the infarct center with severe ultrastructural damages, which also might be an area of little or absent of blood reflow. Conversely, the peripheral-enhanced area is the infarct periphery with moderate myocardial damages.
Androgens regulate blood pressure and renal alpha 2-adrenergic receptors in a parallel fashion in the spontaneously hypertensive rat (SHR). The present studies investigated whether this regulation of renal alpha 2B-adrenergic receptors occurs at the mRNA level. Male and female SHR were gonadectomized at 4 weeks of age. The gonadectomized rats were implanted with or without testosterone propionate. Sham-gonadectomized rats served as controls. Total kidney RNA was purified, and alpha 2B-adrenergic receptor mRNA was quantified with a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The assay uses a mimic RNA added at known concentrations to the sample RNA. The mimic was constructed from the target sequence in the alpha 2B-adrenergic receptor mRNA plus a 20-bp insertion of a random nucleotide sequence. The amount of alpha 2B-adrenergic receptor mRNA present in each sample was obtained by determining the equivalence point between the amount of RT-PCR product formed in the target band versus the mimic band, which were resolved by gel electrophoresis. Intact males had more than two times as much alpha 2B-adrenergic receptor mRNA as intact females. Castration of males reduced the male-female difference by more than 60%. Ovariectomy slightly increased the alpha 2B-adrenergic receptor mRNA level compared with that of intact females. Treatment with testosterone elevated alpha 2B-adrenergic receptor mRNA levels of gonadectomized males and females to the level of intact males. The alpha 2B-adrenergic receptor mRNA levels correlated remarkably well with renal alpha 2-adrenergic receptor density. We conclude that testosterone regulates renal alpha 2B-adrenergic receptor gene expression at the mRNA level in the SHR.
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Male spontaneously hypertensive rats (SHR) have higher blood pressure than females. We compared renal alpha 2-adrenergic receptor density among intact SHR and Wistar-Kyoto (WKY) rats of both sexes, male and female SHR gonadectomized at 4 weeks of age, and gonadectomized SHR supplemented with testosterone. Additional groups of SHR were treated with enalapril (30 mg/kg per day), an angiotensin-converting enzyme inhibitor, from 5 to 14 weeks of age. Renal alpha 2-adrenergic receptor density was higher in males than females in both SHR and WKY rats. Female SHR and WKY rats had identical low renal alpha 2-adrenergic receptor density. Castration of male SHR reduced the male-female differences in blood pressure and renal alpha 2-adrenergic receptor density by 60%. Treatment with testosterone raised blood pressure and renal alpha 2-adrenergic receptor density to the intact male levels in both gonadectomized males and females. Treatment with enalapril decreased blood pressure but not renal alpha 2-adrenergic receptor density in both male and female SHR. We conclude that (1) both renal alpha 2-adrenergic receptor density and blood pressure are influenced by sex in SHR and WKY, (2) renal alpha 2-adrenergic receptor density like blood pressure is regulated by androgens, and (3) increased renal alpha 2-adrenergic receptor density is not a consequence of high blood pressure in male SHR.
Extrafollicular reticulum cells in lymph nodes are heterogeneous. They express cytokeratins, desmin, and/or vimentin as their intermediate filament profile. Using those markers, we undertook an immunohistochemical study of human lymph nodes under various pathologic conditions. Samples included 15 simple reactive lymph nodes, 7 follicular hyperplasia, 1 necrotizing lymphadenitis, 4 tuberculous lymphadenitis, 13 malignant lymphoma (9 non-Hodgkin's and 4 Hodgkin's lymphomas), and 11 metastatic adenocarcinoma. In lymph nodes with follicular hyperplasia, cytokeratin and/or desmin expressing reticulum cells displayed a characteristic dendritic meshwork in the subcapsular, perisinusoidal, and paracortical regions. In other forms reactive lymph nodes, they were similarly distributed but were less prominent. By SDS-PAGE and immunoblotting, cytokeratin polypeptides were identified. In necrotizing lymphadenitis, they were increased and the pattern of distribution was disturbed. In tuberculous lymphadenitis, they were also increased and located at nongranulomatous as well as in perigranulomatous areas. In lymphomas the reticular meshwork was entirely obliterated. Cytokeratin or desmin expressing reticulum cells were rarely seen within tumors. The reticular meshwork was also obliterated in metastatic carcinoma. However, the meshwork was maintained in uninvolved areas. In conclusion, extrafollicular reticulum cells displayed characteristic patterns of distribution under various pathologic conditions, and may be implicated in the pathogenesis of those pathologic conditions in human lymph nodes.
A series of five endodermal sinus tumors was studied for their cytoskeletal and other phenotypic markers. They included 2 ovarian, 2 testicular, and 1 inguinal tumors. The cytoskeletal expression was also studied by gel electrophoresis and immunoblotting. Every tumor was diffusely and strongly immunostained for cytokeratin. By SDS-PAGE and immunoblotting, cytokeratins 8 & 18 were detected. Vimentin was focally coexpressed in 4 cases. The stroma was diffusely immunostained for vimentin. None of them expressed desmin, neurofilament, or glial filament protein. Desmoplakin was expressed only in one ovarian tumor. Alpha-fetoprotein and S-100 protein were also diffusely positive among the neoplastic cells; intracytoplasmic globules were especially strongly immunostained. These findings suggest that endodermal sinus tumors represent a group of pure malignant epithelial neoplasms, and may be regarded as primitive carcinomas.
Generalized estimating equations (GEEs) (Liang and Zeger, 1986, Biometrika 73, 13-22) are used to fit genetic models to binary disease data for families of subjects in case-control studies. The GEEs include model specification of both the disease probabilities and the two-way (and possibly three-way) correlation coefficients of the family disease data. These quantities are modelled as nonlinear functions of unobserved genotypes, observed environmental covariates, and the unknown parameters; the functions reflect the method used to ascertain the family data. Goodness of fit is tested by allowing more flexible forms for the correlation coefficients, regressing them against covariates specific to the relevant pair (or triple) of family members. The approach is applied to family data obtained from simulated and real case-control studies. This semiparametric approach is less dependent on unverifiable assumptions and more computationally tractable than other methods for segregation analysis.
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No ideal prosthetic heart valve exists. While polyurethane copolymers possess excellent physical properties, thrombosis and embolism remain a problem and compounds designed to be less thrombogenic have been prone to biodegradation and failure ('cracking'). We tested a new material which has an elastomeric silicone applied to the polymer surface. A hydrophilic film of protamine and gelatin is covalently bonded to the silicone--this obviates the need for preclotting and should permit endothelial growth. The material was tested by implantation during cardiopulmonary bypass as patches in the mitral valve of six weanling sheep (weanling sheep provide a standard model of accelerated calcification for bioprosthetic heart valves). Prosthetic valves constructed from the material were implanted in an additional four animals, but all of these died within 30 days with heavily calcified valves. Four of the six animals with patches survived and were sacrificed 180 days after surgery when the patches were found to be well healed to native tissue, with collagenous ingrowth and partial endothelial covering. Scanning electron microscopy confirmed good healing, tissue ingrowth and good surface endothelium. The material functioned well as a patch in the mitral valve, allowing tissue ingrowth and endothelial growth on the surface of the patch. The material is not able to resist the strains experienced by a mitral valve prosthesis. Prospects for improved polymers for intravascular applications are good.
We studied host endothelial growth and calcification of bovine pericardial valve prostheses treated with: (A) 0.625% glutaraldehyde + 4% formaldehyde, (B) 99.5% glycerol or (C) 99.5% glycerol + 4% formaldehyde. Twenty-three stentless chordally supported bileaflet pericardial mitral valves with treatments A (n = 6), B (n = 6) or C (n = 11) were implanted in juvenile sheep for 125-273 days. After sacrifice, the anterior cusp from the annulus to papillary muscle of each valve was examined by scanning electron microscopy for the presence of endothelial cells, and the intrinsic calcification of each valve was determined by measuring calcium (micrograms/mg dry weight) from another 1 cm2 piece of grossly normal cusp. Sixty pieces of 1 cm2 pericardium with treatment A, B or C (n = 20 in each group) were implanted in 30 rats for 70 days. Calcium analysis and histology study of the implants were performed. In sheep, within a similar range of implantation periods, the endothelial growth rate of the valves was the highest in group B, 100% (6/6); group C was 45.5% (5/11) and A 16.7% (1/6). There were no significant differences in calcium among groups A, B and C. In rat implants, the calcium of group B was much lower than that of A or C (B = 6.92 +/- 4.46 vs A = 144.52 +/- 27.66 or C = 240.54 +/- 13.47, P < 0.05) although its histology showed more severe degeneration and inflammatory changes. Pericardial mitral valves treated with glycerol show satisfactory biocompatibility with regard to host endothelial growth and prevention of calcification; however, these tissues show evidence of rapid degeneration.(ABSTRACT TRUNCATED AT 250 WORDS)
To evaluate the distribution of alpha-smooth muscle actin (alpha-SMA) positive cells in various liver diseases, we undertook an immunohistochemical study of liver diseases including chronic persistent hepatitis, chronic active hepatitis, liver cirrhosis, intrahepatic cholelithiasis and hepatocellular carcinoma. As a control, fetal livers (gestational age: 22-26 weeks) showed alpha-SMA positive cells along the blood vessels of the portal area, terminal hepatic venules and at perisinusoidal spaces. Perisinusoidal alpha-SMA positive cells were bipolar shaped and had round nuclei. In chronic persistent hepatitis, a few alpha-SMA positive cells were admixed with the inflammatory infiltrates mostly along the intact limiting plate. They were also detected multifocally in a linear pattern along the dilated sinusoid. In chronic active hepatitis, very strong alpha-SMA staining was detected at the site of piecemeal necrosis and adjacent lobules. A-SMA expression was decreased in some cases after interferon treatment. In cases of transplanted liver biopsies, expression of intralobular alpha-SMA was diffusely increased but showed no correlation with degree of acute rejection. Cirrhotic livers revealed strong alpha-SMA positivity in fibrous septae as well as in the perisinusoidal space of intact hepatocytes at the leading edge of fibrosis. Interlobular bile ducts were concentrically circumscribed by alpha-SMA positive cells in cases of intrahepatic cholelithiasis. In trabecular type hepatocellular carcinomas, most sinusoidal lining cells were positive for alpha-SMA. Most intralobular alpha-SMA positive cells represent, if not all, perisinusoidal cells (PSCs) which are involved in intralobular fibrogenesis in various liver diseases.(ABSTRACT TRUNCATED AT 250 WORDS)