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Biomedical subjects

S C Wu

Publications and source records attributed to S C Wu.

At least 145 records · Page 8Linked to original sources
PubMed1988

Cell differentiation features in embryos resulting from interphylum nuclear transplantation: echinoderm nucleus to ascidian zygote cytoplasm.

When an echinoderm nucleus was transplanted into an ascidian zygote cytoplast there was developmental cooperation at the cellular level between nucleus and cytoplasm of these normally nonhybridizable species. A blastula stage nucleus from the sand dollar Echinarachnius parma was injected into an activated but nonnucleate egg fragment of the ascidian Ciona intestinalis. During culture, some of the "hybrid" embryos displayed ultrastructural evidence of cellular differentiation. Two recognizable features were (1) extracellular matrix components, and (2) neural cell characteristics, including elaboration of associated cilia. Nonnucleate zygote fragments alone, and such fragments injected with seawater or punctured by glass needle, did not develop organized subcellular structures. Morphologic expressions resulting from nuclear transplantations between these two phyla (Echinodermata and Chordata) seemingly indicate functional interactions at a gene regulatory level. Creation of such nuclear-cytoplasmic hybrids suggests thereby a means of exploring the nature of the egg cytoplasmic agents in ascidian embryos that appear to determine gene expression related to histospecific differentiation products.

Animals↗
PubMed1988

Latin hypercube sampling and the sensitivity analysis of a Monte Carlo epidemic model.

Discrete, algorithmic simulation and Monte Carlo methodologies are currently used in population biology, connectionist cognitive modeling, and physics. However, little is typically known about the sensitivity of such models to changes in the values of the model features. Traditional methods of sensitivity analysis for systems of differential equations do not apply. Sometimes, one or two parameters are modified at a time in an ad hoc fashion in an attempt to assess sensitivity. To include more model features and their interactions in a sensitivity study, while limiting computer utilization, various sampling methods have been suggested. In this article, a sensitivity study based on a Latin hypercube (LH) sampling design is compared with a similar study using a full factorial (FF), fixed-point sample. A discrete, Monte Carlo model of epidemics of influenzavirus infections in a human community is used for illustrative purposes. Although the FF scheme used over 14 times as many samples as the LH sampling one, both provided comparable predictive ability and comparable information about simulation sensitivity to model features.

Adolescent↗
PubMed1988

Preventing heart disease: is treating the high risk sufficient?

Monte Carlo simulation was used to assess the effects of several intervention strategies on coronary heart disease mortality rates in a Finnish and a North American cohort. Lowering total serum cholesterol by 4%, smoking by 15%, and diastolic blood pressure by 3% for the whole cohort would be expected to reduce the incidence of non-fatal myocardial infarction by at least 13% and coronary heart disease deaths by at least 18%. Lowering serum cholesterol by 34%, diastolic blood pressure to 90 mmHg, and reducing smoking by 20% in the subset of the population with all three risk factors in the highest quartile would result in a 6-8% reduction in non-fatal myocardial infarction and a 2-9% reduction in deaths from coronary heart disease in these cohorts. These data demonstrate that in populations with a relatively high incidence of heart disease, treating the entire population will produce larger effects than focusing only on high-risk populations.

Adolescent↗
PubMed1988

Diabetes mellitus associated with cystic fibrosis.

The prevalence of overt diabetes mellitus and carbohydrate intolerance was studied in 448 patients with cystic fibrosis (CF). Insulin-dependent diabetes (IDDM) developed in 7.6% of patients (13 male and 21 female). Survival was significantly lower (P less than 0.01) in the IDDM-CF group, with fewer than 25% surviving to age 30 years, whereas nearly 60% of the nondiabetic CF population reached this age. A significant deterioration in CF clinical status, based on NIH score, became apparent 2 years before onset of overt IDDM (P less than 0.05 at 2 years prior, P less than 0.01 at IDDM diagnosis). Total glycosylated hemoglobin (HbA1) was significantly (P less than 0.001) higher for the total CF population (7.3% +/- 1.2%) than for the general non-CF population (6.5% +/- 0.7%), and in the IDDM-CF group (P less than 0.05) compared with normoglycemic CF control patients. Female patients had a higher mean HbA1 after 12 years of age than their male counterparts did (P less than 0.02). HBA1 did not predict the development of IDDM, but there was a weak inverse relationship between HbA1 and both NIH clinical score (r = -0.41, P less than 0.02) and standard pulmonary function tests (forced vital capacity, r = -0.25, P less than 0.01) in the general CF population. Therefore, impaired carbohydrate tolerance in CF is associated with progressive clinical deterioration.

Adolescent↗
PubMed1987

Improvement in long-term survival among patients hospitalized with acute myocardial infarction, 1970 to 1980. The Minnesota Heart Survey.

The mortality rate associated with coronary heart disease in the United States has declined steadily since 1968, but the reasons for this favorable trend have not been completely elucidated. In particular, it is not clear to what extent the decline reflects decreasing incidence as opposed to improved survival. To assess whether improved survival after myocardial infarction has contributed to the decline, the Minnesota Heart Survey compared the four-year survival rate in patients discharged with a diagnosis of acute myocardial infarction from hospitals in the Twin Cities area in 1970 and 1980. After adjustment for clinical characteristics related to outcome, the survival rate among patients with a definite myocardial infarction was significantly higher in the 1980 than in the 1970 group. The four-year survival for men was 35 percent better in the 1980 than in the 1970 group (95 percent confidence interval, 21 to 50 percent), and for women it was 27 percent better (95 percent confidence interval, 1 to 46 percent). Improvement in survival during the period of hospitalization accounted for 70 percent of the overall gain in survival between 1970 and 1980 in men and for virtually all of the gain in women. We conclude that improved long-term survival among patients with acute myocardial infarction has made an important contribution to the decline in mortality from coronary disease.

Female↗
PubMed1987

Influence of race of cadaveric kidney donor and recipient on graft survival: a multifactorial analysis.

Actuarial survival analysis of 889 cadaver transplant patients between 1972 and 1981 in Michigan reveals functional graft (P = .0003) and patient (P = .004) survivals are improved when donors and recipients are of the same race (black or white). The Cox regression model for multifactorial analysis confirms the significantly lower graft survival for the mixed racial combination group with a relative risk of 1.27 (P less than .05). By this analysis, other significant factors adversely affecting the graft survival rates include diabetes as a cause of end-stage renal disease, earlier date of transplantation, shorter duration of prior dialysis, and a significant center effect. Patient survival has a significantly greater relative risk for the black to white racial combination, diabetes, earlier calendar year of transplantation, and age of patient. While the mixed racial group was slightly older (delta = 2 years), had more hypertension, less glomerulonephritis, and more HLA mismatches, our analysis by the Cox regression model suggests that these factors played only minor roles (P greater than .05) regarding graft survival rates. Therefore, our data suggest that independent of several other factors, cadaver kidneys have a better functional outcome when they are transplanted into recipients of the same race.

Actuarial Analysis↗
PubMed1987

Multiple primary lung cancers.

From November 1957 to June 1984 at Shanghai Chest Hospital, 30 cases of multiple primary lung cancers were confirmed, based on clinical characteristics, diagnostic process, histologic type, treatment, and prognosis. Out of 3,815 cases of resected primary lung cancer, the incidence of multiple primary lung cancers was 0.8 percent. There were ten synchronous cases and 20 metachronous cases. Seventeen cases were unilateral, and 13 cases were bilateral, of which only one case was synchronous, and the remaining 12 cases were postoperative resection of an opposite lesion. Among the ten synchronous cases, four cases of multiple primary lung cancers were definitely diagnosed before surgery by chest x-ray films or fiberoptic bronchoscopy. Among the 20 metachronous cases, 11 cases were definitely diagnosed before surgery as the second primary lesion by chest x-ray films taken during periodic follow-ups after the initial resection, while nine cases were proven by thoracotomy. All of the 15 cases definitely diagnosed before surgery as multiple primary lung cancers were according to our criteria. Histologically, adenocarcinoma was relatively scarce, at a rate of 13 percent (4/30); but epidermoid carcinoma was predominant, at a rate of 87 percent (26/30), of which 11 cases were accompanied by adenocarcinoma or large-cell undifferentiated carcinoma. The average postoperative survival in the ten synchronous cases was 29 months and in the 20 metachronous cases was 26.2 months, counting from the time of the second operation. The criteria of clinicopathologic findings, early diagnostic procedure, and surgery for multiple primary lung cancers were also discussed.

Adult↗
PubMed1987

[Multiple primary lung cancer].

From November 1957 to June 1984, 30 patients with multiple primary lung cancer were diagnosed, basing on clinical features, diagnostic means, histologic type, treatment and prognosis. Out of 3,815 cases of resected primary lung cancer, the incidence of multiple primary cancer was 0.8%. There were 10 synchronous and 20 metachronous cases. There were 17 unilateral, only 1 simultaneous bilateral and 12 contralateral after resection of cancer in the opposite lung. Four of the 10 synchronous cases were definitely diagnosed preoperatively. Among the 20 metachronous cases, 9 were definitely diagnosed as a second primary lesion and the other 11 were proved by thoracotomy. Pathologically, 19 had identical types (15 squamous cell and 4 adenocarcinoma) but 11 had double types (9 squamous cell + adenocarcinoma, 2 squamous cell + anaplastic). The average survival of these 30 patients was 27.1 months, that in the synchronous group was 29 months and that in the metachronous group was 26.2 months. The 5 year survival rate of the synchronous cases was 35%, that of the metachronous cases was 42%. The clinicopathological criteria of multiple primary lung cancer, early diagnostic and operative procedure are also discussed.

Adenocarcinoma↗
PubMed1986

Menstrual blood loss, haemoglobin and ferritin concentration of Beijing women wearing steel ring, VCu 200, and TCu 220c IUDs.

Menstrual blood loss (MBL), serum ferritin and whole blood cyanmethemoglobin were measured at pre- and 1, 3, 6, 12, 18 and 24th postinsertion cycles in 60 women wearing the Steel Ring, the Copper V (VCu 200) or the Copper T (TCu 220c). The MBL, incidence of menorrhagia and iron deficiency anemia were lower among users of the Steel Ring than among users of the Copper V and T. Anemia occurred later and the duration of menstruation was shorter with the Steel Ring than with the Copper T. There were no statistically significant differences between the Copper V and T.

Anemia↗
PubMed1986

Beta-blocker versus diuretic for control of the blood pressure response to stress in hypertensive patients.

To compare the antihypertensive effects of beta-blockers and diuretics on the blood pressure increase to stress, a randomized single-blind crossover study was performed in 27 patients with mild or moderate hypertension. At the initial examination and after two subsequent periods of therapy with 100 mg atenolol or with a combination of 50 mg hydrochlorothiazide and 5 mg amiloride hydrochloride, once a day, blood pressure and heart rate were measured at rest, during mental arithmetic, sustained handgrip and cycloergometric test. Both treatment significantly decreased supine and standing systolic and diastolic pressure at rest, during and immediately after mental stress and isometric exercise, with the reduction of diastolic pressure significantly greater after atenolol. During dynamic exercise, systolic and diastolic pressures were significantly decreased by diuretics at the lowest work-load only, whereas beta-blocker caused significant and greater blood pressure reductions throughout the exercise. The combination of two classes of drug normalized resting blood pressure in 8 of 9 subjects in which the monotherapy had failed to obtain values less than 140/90 mmHg and gave a better control of systolic and diastolic pressures throughout all the stress tests. It is concluded that atenolol is more effective than diuretics during stress, suggesting that beta-blocking drugs are the first choice treatment for mild to moderate hypertension and that when the antihypertensive effect of a single agent is insufficient, a combination of beta-blockers and diuretics is also effective during stress.

Adult↗
PubMed1986

[Chemotherapy combined with selective resection in small cell lung cancer--analysis of 239 patients].

From 1957 to 1976, 143 patients with small cell lung cancer (SCLC) were treated with surgical resection followed by chemotherapy. The 5 year survival rates were 38.7%, 8.7% and 3.5% in stages I, II and III. The prognostic factors were clinical stage and chemotherapy. 4 stage I and 1 stage II patients without chemotherapy have survived for more than 5 years. It seems to suggest that SCLC in stage I be indicated for surgery. 4 stage III have survived for more than 5 years, all of whom had received postoperative chemotherapy for more than 4 courses. From 1980 to 1982, 96 patients with SCLC were treated, 37 of whom by chemotherapy combined with surgery. 11/37 patients were alive for more than 2 years, 7 for more than 3 years and 4 for more than 4 years. In the preoperative chemotherapy followed by selective resection plus postoperative chemotherapy group (13 patients), the mean survival time was 22.7 months, but in the postoperative chemotherapy group (24 patients), it was 11.0 months. It indicates that full-dose chemotherapy before and after operation may be superior to the postoperative chemotherapy alone.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Correlation between lipid fluidity and tryptic susceptibility of Ca2+-ATPase in sarcoplasmic reticulum membranes.

Lipid fluidity in native and denatured sarcoplasmic reticulum membranes and extracted lipids was monitored between -30 and 30 degrees C using trans-parinaric acid as a fluorescent probe. In addition to a large increase in fluidity between -30 and 0 degree C in each system, a phase change centered near 10 degrees C was observed in the extracted lipids but not in either the native or denatured membranes. A significant change in fluorescence intensity near 15 degrees C was observed in native sarcoplasmic reticulum membranes, however, when trans-parinaric acid was excited by energy transfer from tryptophan residues of the membrane protein. When Ca2+-ATPase was subjected to proteolytic cleavage by trypsin as a function of temperature, a change in susceptibility was detected at about 15-20 degrees C in the native membranes but not in a solubilized preparation. It is proposed that one or more structural changes in the microenvironment of Ca2+-ATPase in the native membrane occur between 15 and 20 degrees C which may be related to the change in apparent activation energy which is observed for this enzyme.

Animals↗
PubMed1985

A deterministic approach for the estimation of mutation rates in cultured mammalian cells.

Unequal growth rates between mutant and wild-type cells in a large population constitute a problem for the estimation of mutation rate. Over a period of cell growth, a selective advantage of one cell type over the other might lead to considerable error in the estimation of mutation rate if equal growth rates are assumed. In this study, we propose a formula and apply it to the estimation of spontaneous mutation rate in a growing population of Chinese hamster V79 cells in which ouabain-resistant mutant cells exhibit a slower growth rate than the wild-type cells. The formula is a generalization of that previously presented by Armitage (1953), and this is the first attempt to apply the deterministic approach for mutation rate estimation to cultured mammalian cells. The value of the estimated rate is compared with that derived from a parallel experiment using the fluctuation test of Luria and Delbrück (1943). The limitations and advantages of taking the deterministic approach to mutation rate estimation in mammalian cell systems are discussed.

Animals↗