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Biomedical subjects

C C Hsu

Publications and source records attributed to C C Hsu.

At least 145 records · Page 8Linked to original sources
PubMed1994

A membrane form of brain L-glutamate decarboxylase: identification, isolation, and its relation to insulin-dependent mellitus.

A membrane form of L-glutamate decarboxylase (GAD) was identified and purified to apparent homogeneity from hog brain. The purified GAD was established as an integral membrane protein by phase-partitioning assay, charge-shift electrophoresis, and chromatography on a hydrophobic interaction column. This membrane GAD has a native molecular mass of 96 +/- 5 kDa and is a homodimer of 48 +/- 3-kDa subunits. Immunoprecipitation and immunoblotting tests revealed the presence of antibodies against this membrane GAD in sera from patients with insulin-dependent diabetes mellitus. Since this form of GAD appears to be an integral membrane protein and is presumed to have extracellular domains exposed, it seems reasonable to suggest that membrane GAD is more likely than soluble GAD to be involved in the pathogenesis of insulin-dependent diabetes and related autoimmune disorders such as stiff-man syndrome.

Animals↗
PubMed1994

The utility of fetal biometry as an adjunct to the multiple-marker screening test for Down syndrome.

OBJECTIVE: Our purpose was to investigate fetal biometry as an adjunct to the multiple-marker screen (maternal age, serum alpha-fetoprotein, estriol, and human chorionic gonadotropin) for Down syndrome. STUDY DESIGN: Fifty-two cases of Down syndrome were compared with 7514 normal fetuses. The measured/predicted femur length ratio had the best discriminant value (1.0 +/- 0.11 vs 0.93 +/- 0.13, p < 0.0001). Multivariate gaussian algorithms were developed and each computed a likelihood ratio for Down syndrome. The trivariate algorithm incorporated the three maternal analytes, whereas the quadrivariate version also included the femur length ratio. The study population included 38 cases of Down syndrome and 1098 euploid controls. The midtrimester risk was the product of the age-related risk and the likelihood ratio. RESULTS: The relative difference in the femur length ratio between normal and affected fetuses was small in comparison to that of the maternal serum analytes. At a risk cutoff of > or = 1:190 the detection rates were similar and actually favored the trivariate algorithm but differed only by one case of Down syndrome. CONCLUSION: The addition of the measured/predicted femur length ratio had a negligible effect on the performance of the multiple-marker screening test.

Adult↗
PubMed1994

Differential accuracy of elastomeric recording materials and associated weight change.

Six interocclusal recording materials: COE Bite Creme, Blu-Mousse, Correct Bite, Blue Velvet, Memosil C.D. and Ramitec brands, were studied for evaluation of their dimensional stability and associated weight change. The materials were divided into six groups of 10 samples and tested between metal dental casts on the hydroptic test and measurement system. Dimensional changes among the materials were not significantly different. Weight changes among materials were significantly different but did not exceed 0.1%. All 6 brands were highly accurate and dimensionally stable.

Analysis of Variance↗
PubMed1994

Blood serum levels of PCDFs and PCBs in Yu-Cheng children peri-natally exposed to a toxic rice oil.

Children secondarily exposed through their mothers to a toxic rice oil containing PCDFs and PCBs in the Yu-cheng incident have shown developmental delay even a decade after the incident. Forty-five serum samples were collected from these children in February 1991 ad small amounts analyzed for their contaminant content using sample enrichment and isotope dilution mass spectrometry. In about one-half the samples, detectable levels of PCDFs and PCBs could still be determined with average values for 2, 3, 4, 7, 8-PnCDF and 1, 2, 3, 4, 7, 8-HxCDF of 300 and 620 ng/kg serum lipid, respectively. The mean of the total PCBs on a whole weight basis was 7.5 micrograms/kg. These concentrations of PCDFs and PCBs are still 10 to 25 times higher than those from a matched control population. Although the serum levels did not correlate with developmental delays, those for the two PCDFs but not the total PCBs correlated with duration of breast feeding indicative of postnatal exposure. The results of this study suggest that estimation of past prenatal exposure of children to PCDFs is best carried out using current mother and not current child blood concentrations.

Adult↗
PubMed1994

Androgenesis and gynogenesis are not causative in early pregnancy loss in humans.

OBJECTIVE: Androgenetic and gynogenetic embryos in the mouse have been shown to fail early in development, exhibiting many features that are similar to those seen in early pregnancy loss in humans. Because androgenetic or gynogenetic abortuses contain the genetic complement from a single paternal or maternal genome, we used locus-specific minisatellite probes to determine individual genetic relationships and parentage from samples of parental blood and abortus tissue, to investigate whether androgenesis and gynogenesis contribute to the cause of early pregnancy loss. STUDY DESIGN: We carried out prospective recruitment over 2 years of 145 patients admitted to a teaching hospital in Cambridge with ultrasonographic confirmation of early pregnancy failure. RESULTS: Blood and products of conception suitable for complete analysis were obtained from 75 cases. Twenty-seven (56%) of the 48 samples that could be karyotyped had normal chromosome complements, with trisomy 16 the most frequent aberration (5/21). Both paternal and maternal genomic contributions to the abortuses were found in all cases investigated, irrespective of the karyotypes of the tissue. Germline mutations were detected in six of 42 (7.1% per gamete) hybridizations with lambda MS1 and in one of 15 (3.3% per gamete) with p lambda g3, which is higher than the rate estimate for the general population. No inappropriate paternity was detected. CONCLUSION: Androgenesis and gynogenesis are unlikely to be causative in the cause of human early pregnancy loss, but germline mutations even in the presence of a normal karyotype could be influential.

Abortion, Missed↗
PubMed1994

Feasibility study on spray-drying protein pharmaceuticals: recombinant human growth hormone and tissue-type plasminogen activator.

The feasibility of spray-drying solutions of recombinant methionyl human growth hormone (hGH) and tissue-type plasminogen activator (t-PA) was investigated. hGH was formulated in a mannitol phosphate buffer and t-PA was used in an arginine phosphate formulation containing 0.004% (w/v) polysorbate 80. Using filtered air (90-150 degrees C) as the drying medium, hGH could be dried to a residual moisture content of < or = 4%. However, approximately 25% of the protein was degraded during the processing. Results of atomization studies suggest that surface denaturation at the air-liquid interface of the droplets in the spray plays a major role in the degradation of the protein. The addition of 0.1% (w/v) polysorbate 20 into the hGH formulation reduced the formation of soluble and insoluble aggregates by approximately 90% during atomization. During spray-drying the addition of 0.1% (w/v) polysorbate 20 reduced the formation of soluble and insoluble aggregates by approximately 70 and 85%, respectively. In contrast, t-PA remained intact upon atomization. Depending on the spray-drying conditions, product powders with a residual moisture content between 5 and 8% were obtained. No oxidation, aggregation, or denaturation occurred in the protein under several operation conditions. Overall, this study demonstrates that it is feasible to spray-dry t-PA in the current marketed formulation.

Calorimetry, Differential Scanning↗
PubMed1994

Musculoskeletal changes in children prenatally exposed to polychlorinated biphenyls and related compounds (Yu-Cheng children).

Fifty-five Yu-Cheng (oil-disease) children born between 1978 and 1985 to mothers who ate PCB-contaminated rice oil in 1978-1979 were studied and compared to age- and sex-matched control subjects in 1991. The children's growth profiles, bone mineral density and soft tissue composition, joint laxity, and serum parathyroid hormone, vitamin D, calcium, alkaline phosphatase, and phosphate were compared. The Yu-Cheng children were 3.1 cm (p < .05) smaller and had less total lean mass and soft tissue mass as compared to the matched control subjects. All other parameters studied were similar in both groups. The shorter height and decreased total lean mass and soft tissue content were only seen in the Yu-Cheng children who were the first born after the ingestion, but not in subsequent children. This was most likely due to decreased body burdens of the PCBs and related contaminants over time in the mothers.

Birth Order↗
PubMed1994

The benefits of low-dose aspirin therapy in women with impaired uterine perfusion during assisted conception.

The objective of this long-running study was to determine whether the addition of low-dose aspirin to a standard hormone replacement therapy (HRT) protocol improved uterine perfusion during assisted conception. A total of 99 women scheduled for frozen embryo replacement were studied. Endometrial preparation was with a standard buserelin/HRT protocol. Uterine perfusion was assessed by Doppler ultrasound and classified as impaired or normal. In their first attempts, those with impaired perfusion (group I, n = 37) received low doses of aspirin [150 mg (n = 26) or 300 mg daily (n = 11)], starting from day 13 of HRT. Women with normal perfusion (group II) did not receive aspirin. In subsequent attempts, those from group I were arbitrarily allocated to start aspirin on day 1 or day 13 of HRT, and 10 women from group II were arbitrarily selected to receive aspirin from day 1 of HRT. In group I, the cancellation (46 versus 36%) and pregnancy rates (15 versus 25%) in those who received 150 or 300 mg aspirin daily were similar. In those with cancelled first attempts, good perfusion was achieved in 82 versus 20% (P < 0.02) of subsequent attempts using aspirin from day 1 versus day 13 of HRT. Higher pregnancy rates (47 versus 17%) were achieved in those taking aspirin from day 1 of HRT. In group II, pregnancy rates were not statistically different in those who did or did not receive aspirin during their subsequent attempts (10 versus 35%). The addition of low-dose aspirin to a standard HRT protocol in women with impaired uterine perfusion is associated with improved blood flow and satisfactory pregnancy rates.

Aspirin↗
PubMed1994

Effects of prenatal exposure to PCBs on the neurological function of children: a neuropsychological and neurophysiological study.

To determine the long-term neurotoxicity of prenatal exposure to polychlorinated biphenyls (PCBs), 54 children--27 'Yu-Cheng' ('oil disease') children and 27 controls--were administered a battery of tests, including the WISC-R, auditory event-related potentials (P300), pattern visual evoked potentials (P-VEPs) and somatosensory evoked potentials (SSEPs). Full-scale IQ scores on the WISC-R were lower for the Yu-Cheng group than for the control group. Mean P300 latencies were significantly longer, and P300 amplitude significantly more reduced, in the Yu-Cheng group than in the control group at Cz and Pz. There were no significant difference in peak latencies and amplitudes between the two groups for P-VEPs and SSEPs. These findings suggest that prenatal exposure to PCBs tends to affect high cortical function rather than the sensory pathway in the developing brain.

Child↗
PubMed1994

Intestinal schistosomiasis japonica: CT-pathologic correlation.

PURPOSE: To study the pathologic basis of intestinal wall calcification caused by Schistosoma japonicum visualized with computed tomography (CT). MATERIALS AND METHODS: Twelve patients underwent CT of the abdomen to detect what pathologic examination proved to be schistosomiasis japonica. Eight intestinal specimens from five of the patients were subjected to radiography, and the pathologic and radiographic findings were correlated. RESULTS: CT demonstrated curvilinear or nodular calcification in the colon in 11 patients, in the appendix in two, and in the distal ileum in one. In five patients, calcifications resembling tram tracks were found in the sigmoid colon. Pathologic examination of the specimens showed calcified eggs of S japonicum deposited more extensively in the submucosa and subserosa than in the muscularis propria, which led to the tram-track appearance. CONCLUSION: The extensive curvilinear or tram-track calcification found in the colon in patients with schistosomiasis japonica is calcification of deposited eggs.

Aged↗
PubMed1994

A 6-year follow-up of behavior and activity disorders in the Taiwan Yu-cheng children.

OBJECTIVES: The relationship of behavior and activity levels to the interval between outbreak and year of birth and to age of children is explored in Taiwanese children exposed in utero to heat-degraded polychlorinated biphenyls (PCBs)--the Yu-cheng children. Additionally, the relationship of the scores to chemical, physical, and cognitive findings is described. METHODS: With Rutter's Child Behavior Scale A and a modified Werry-Weiss-Peters Activity Scale, 118 Yu-chen children and matched controls were followed biannually from 1985 to 1991. RESULTS: At each year, the Yu-cheng children scored 7% to 43% worse (mean = 23%) than control children on the Rutter scale. At any fixed age, the Yu-cheng children scored 11% to 63% (mean = 28%) worse. The effect for children born later did not differ from that for those born earlier; neither was there any improvement as the children aged. A similar but weaker picture was seen for the activity score. These behavioral findings were not related to physical or cognitive findings or to serum PCB levels. CONCLUSIONS: In utero exposure to heat-degraded PCBs appears to cause mildly disordered behavior and increased activity level; the effect persists over time and is similar in children born up to 6 years after the mothers were exposed.

Case-Control Studies↗
PubMed1994

Psychological maladjustment and academic achievement: a cross-cultural study of Japanese, Chinese, and American high school students.

Psychological maladjustment and its relation to academic achievement, parental expectations, and parental satisfaction were studied in a cross-national sample of 1,386 American, 1,633 Chinese, and 1,247 Japanese eleventh-grade students. 5 indices of maladjustment included measures of stress, depressed mood, academic anxiety, aggression, and somatic complaints. Asian students reported higher levels of parental expectation and lower levels of parental satisfaction concerning academic achievement than their American peers. Nevertheless, Japanese students reported less stress, depressed mood, aggression, academic anxiety, and fewer somatic complaints than did American students. Chinese students reported less stress, academic anxiety, and aggressive feelings than their American counterparts, but did report higher frequencies of depressed mood and somatic complaints. High academic achievement as assessed by a test of mathematics was generally not associated with psychological maladjustment. The only exception was in the United States, where high achievers indicated more frequent feelings of stress than did low achievers.

Achievement↗
PubMed1993

Endothelin 1 mediates endothelial cell-dependent proliferation of vascular pericytes.

The influence of endothelial cells on the growth of vascular pericytes was investigated using human umbilical endothelial cell and bovine retinal pericyte co-culture systems. When pericytes were cultured with endothelial cells, the number of viable pericytes increased significantly, regardless of the presence or absence of physical contact between the two cell types, indicating that endothelial cells can induce proliferation of pericytes through certain secreted factor(s). Evidence that endothelin 1 mediates this action was obtained: endothelin 1 added to the medium was able to substitute for the feeder layer of endothelial cells, and an antiserum against endothelin 1 could neutralize the ability of endothelial cells to promote pericyte growth. RNA blot analysis revealed that pericytes express mRNA for type-A endothelin receptor, a high affinity receptor of endothelin 1.

Animals↗
PubMed1993

A comparative analysis of the accuracy of implant transfer techniques.

Four different implant transfer techniques using two master cast systems (solid cast and Zeiser system) were evaluated and compared with respect to the accuracy with which abutment positions were reproduced. A stainless steel experimental analogue with two anterior and two posterior fixtures and abutments was fabricated. Polyether impressions (14 each) were made by use of four techniques, (I) nonsplinted, (II) splinted with dental floss and acrylic resin, (III) splinted with orthodontic wire and acrylic resin, and (IV) splinted with acrylic resin alone. The fourteen impressions of each technique were divided into two equal groups: group 1, solid cast system, and group 2, Zeiser system. The abutments of each master cast were measured vertically and horizontally with a profile projector. Statistical analysis indicated no significant difference between the splinted and nonsplinted techniques. The Zeiser system provided more accurate interabutment relationships for the posterior region than the solid cast system.

Acrylic Resins↗
PubMed1993

Polysaccharide microcapsules and macroporous beads for enhanced chromatographic separation.

One recent solution to the diffusion problem found in conventional chromatographic separation is the use of dual porosity beads in which large pores allow for convective flow and smaller pores allow for molecular diffusion. In our studies, dual porosity beads were prepared from carrageenan using an emulsion method. Effects of polymer type, polymer concentration, toluene content, gelling temperature, and stirring speed on the structure of porous beads were investigated. In an alternative approach, one of the interacting molecules in affinity chromatography, can be entrapped within semipermeable microcapsules. This has the advantage of increased adsorption capacities. Using blue dextran and albumin as a model system, alginate-chitosan capsules, containing blue dextran, were employed in the recovery of albumin from a saline solution.

Alginates↗
PubMed1993

Familial medullary thyroid carcinoma: report of three cases in a family.

Familial medullary thyroid carcinoma is a distinct clinical entity in which early diagnosis by screening of family members for elevated calcitonin levels can be useful. A 33-year-old female was hospitalized because of an enlarging left thyroid mass. Resected thyroid showed medullary thyroid carcinoma. Her mother had received a total thyroidectomy due to the same disease 10 years previously, and her younger brother had an elevated basal calcitonin level of 468 pg/mL when the index case was diagnosed. The younger brother was advised to undergo surgery; a total thyroidectomy also revealed medullary thyroid carcinoma. There was no evidence of multiple endocrine neoplasia in the family. Recognition of new cases by screening with a basal or provocative test in families of patients with medullary thyroid carcinoma should be mandatory.

Adult↗
PubMed1993

Staging of bladder cancer by transabdominal real-time ultrasound.

In the past six years, there were 726 cases of proved bladder cancer in our hospital. Among these, 376 cases received transabdominal ultrasonographic examination of the urinary bladder for evaluation of the bladder tumor. Two hundred and fourteen cases of them were newly diagnosed as bladder cancer and had adequate pathological specimens for staging of the tumor. The retrospective comparison between preoperative local staging of the bladder tumor by ultrasound and final pathological report showed 78.5% of total accuracy, 9.8% of overstaging, and 11.7% of understaging. The accuracy is 87% for stage A tumor; 60.5% for stage B; 41.2% for stage C; 83.3% for stage D. Strong echogenic foci on the surface or in the tumor were detected in 39.3% (84/214) of cases, which may indicate encrusted stones on the surface of the tumor or intratumoral dystrophic calcification. There was no strong correlation between tumor grading and staging, except that most of the grade I lesions were at stage A (30/31, 97%). The preoperative local staging of urinary bladder cancer by real-time ultrasound might be of great value to determine the management planning and prognosis of the patients.

Adolescent↗