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M L Wu

Publications and source records attributed to M L Wu.

At least 91 records · Page 5Linked to original sources
PubMed1988

Association between a satellite DNA sequence and the Responder of Segregation Distorter in D. melanogaster.

A large array of satellite DNA sequences are always associated with the Responder (Rsp) element of Segregation Distorter in D. melanogaster. In the appropriate genetic backgrounds, Rsp causes aberrant chromatin condensation in spermiogenesis, leading to dysfunction of sperm carrying Rsp, and meiotic drive. The repeat array is deleted or translocated to the Y chromosome whenever Rsp is. Moreover, the translocation of part of Rsp to Y is associated with the translocation of an incomplete repeat array. The number of repeats among 35 independently derived chromosomes correlates nearly perfectly with sensitivity to distortion. We hypothesize that this satellite repeat array represents Responder itself. Finally, the molecular structure of this locus is extremely variable, indicating a very active process of change.

Animals↗
PubMed1988

Errors in reported dietary intakes. II. Long-term recall.

Inconsistent results among case-control studies of diet and cancer may reflect discrepancies between dietary reports based on current habits and actual intakes from the time of cancer initiation in the distant past. To examine the validity of reported past and current diet as measures of past diet, the authors queried 873 men and women in three northern California communities about their diet 11 years earlier in 1972 and about their current diet in 1983. They used the same dietary history questionnaire that had been administered to the subjects in 1972. Retrospectively recalled and currently reported nutrient intakes and measures of body size were compared with original reports obtained in 1972. Mean values of recalled nutrient intakes agreed with mean values of intakes reported in 1972. The agreement held for each sex, community, and nutrient examined. By contrast, mean values of current intakes were smaller than those reported in 1972. Correlation coefficients showed closer agreement between recalled and original intakes than between current and original intakes. Nevertheless, recalled intakes correlated more closely with current intakes than with original ones. Analysis of variance was used to partition the variation in recalled and original intakes into components due to interpersonal variation in true intakes, errors in recall, and residual reporting error. Interpersonal variation accounted for only 20-40% of the variation in dietary intakes, with most of the balance due to reporting error. For comparison, interpersonal variation accounted for 70-85% of the variance of recalled and original reports of body size. These results suggest that inconsistencies among case-control studies of diet may be due to large random measurement errors in individual dietary intakes. The apparent validity and reproducibility of mean dietary measures, averaged over large populations, suggests the need for new designs for studies of diet and disease.

Adult↗
PubMed1988

Personal and environmental characteristics related to epithelial ovarian cancer. I. Reproductive and menstrual events and oral contraceptive use.

In two case-control studies conducted in the six-county San Francisco Bay Area, 111 women diagnosed with epithelial ovarian carcinoma in 1974-1977 and 188 women diagnosed in 1983-1985 were interviewed concerning their menstrual, sexual, and reproductive histories. For comparison, interviews were conducted with 752 control women admitted to the same hospitals within six months of the cases; for cases diagnosed in the later period, interviews were also conducted with an additional 259 population-based controls selected by random digit dialing. Controls were matched to cases by age and race. Qualitative and quantitative findings were similar for the two studies. In the combined data, cases were more likely than their matched controls to have been nulliparous, to have undergone menarche at an early age, and to have refrained from using oral contraceptives. Menopause occurred slightly later for cases than for controls, but the differences were not statistically significant. Neither age at first term pregnancy (20 or more weeks gestation) nor number of term pregnancies was predictive of ovarian cancer risk. The protection afforded by oral contraceptive use was independent of parity, and it increased with increasing duration of use. There were no trends in risk with time since last oral contraceptive use or with time since first use, after adjustment for duration of use. These observations suggest that oral contraceptive use decreases risk for ovarian cancer, rather than merely indicates fertility, which may itself decrease risk of developing the disease. The authors combined reproductive characteristics and oral contraceptive use to estimate a woman's total duration of ovulation, which was positively associated with ovarian cancer risk (p less than 0.001 for trend). These observations support the concept that the greater the duration of ovulation or accompanying endocrinologic phenomena, the greater a woman's risk for ovarian cancer.

Adult↗
PubMed1988

Personal and environmental characteristics related to epithelial ovarian cancer. II. Exposures to talcum powder, tobacco, alcohol, and coffee.

Vaginal exposures to talc and other particulates may play an etiologic role in epithelial ovarian cancer. Surgical sterilization may protect against ovarian cancer by blocking entry of such particulates into the peritoneal cavity. The authors assessed histories of talcum powder use, tubal sterilization, and hysterectomy with ovarian conservation in 188 women in the San Francisco Bay Area with epithelial ovarian cancers diagnosed in 1983-1985 and in 539 control women. To investigate the roles of blood-borne environmental exposures on ovarian cancer risk, they assessed lifetime consumption of coffee, tobacco, and alcohol in these women. Of the 539 controls, 280 were hospitalized women without overt cancer, and 259 were chosen from the general population by random digit telephone dialing. Ninety-seven (52%) of the cancer patients habitually used talcum powder on the perineum, compared with 247 (46%) of the controls. Adjusted for parity, the relative risk (RR) = 1.40, p = 0.06. There were no statistically significant trends with increasing frequency or duration of talc use, and patients did not differ from controls in use of talc on sanitary pads and/or contraceptive diaphragms. Fewer ovarian cancer patients (7%) than controls (13%) reported prior fallopian tube ligation (RR, adjusted for parity, = 0.56, p = 0.06), and fewer patients (20%) than controls (28%) reported prior hysterectomy (RR = 0.66, p = 0.05). The protective effect of hysterectomy was confined to those who underwent this surgery 10 or more years prior to interview and to those who had not undergone prior tubal sterilization. Consumption of cigarettes and alcohol did not differ between cases and controls. By contrast, 11 (6%) cases never regularly consumed coffee, compared with 31 (11%) hospital controls and 26 (10%) population controls (RR, adjusted for smoking, = 2.2, p = 0.03, for the comparison using all controls). Overall, ovarian cancer risk among women who had drunk coffee for more than 40 years was 3.4 times that of women who had never regularly consumed coffee (p less than 0.01). However, the data exhibited no clear trends in risk with increasing consumption. Although risk ratios relating duration of coffee drinking to ovarian cancer were unaffected by adjustment for several characteristics, further study is needed to exclude potential confounding by other unmeasured characteristics.

Adult↗
PubMed1986

Errors in reported dietary intakes. I. Short-term recall.

Measures for quantifying reproducibility and between-subject variability of nutrient intake data are applied to intakes reported in two interviews (1-3 months apart) by 44 male and 17 female healthy white subjects aged 45-75 years. Intakes were assessed by three methods: a dietary history that included consumption frequency and serving size for 71 food items (dietary history method); a combination of individual consumption frequencies with sex-specific mean serving sizes (frequency method); an extrapolation from frequencies and serving sizes of all foods reported for a "typical day" in the specified time period (typical day method). Intake variation within subjects, between subjects, and between methods was assessed by analysis of variance for each sex and for each of the nutrients: total calories, protein, fat, vitamin A, and protein and fat as percentage of total calories. Dietary history-assessed intakes exceeded those assessed by the other two methods. The dietary history versus frequency excess was greater than the dietary history versus typical day excess for calories, fat, and protein, while the reverse was true for vitamin A and fat as percentage of total calories. The typical day method was unreliable for vitamin A because it occasionally produced extremely high, unreproducible intakes. The intraclass correlation coefficient was used to measure a method's ability to distinguish interpersonal variation from within-person error. The frequency method produced less within-person error than did the dietary history method for all nutrients. For absolute intakes, the frequency method produced less interpersonal variation than did the dietary history method, while for relative intakes, the reverse was true. Females reported intakes with less within-person error than did males, and the interpersonal spread of their intakes was smaller. Consequences of these findings for the power and sensitivity of studies on the role of dietary factors in the etiology of chronic disease are explored.

Aged↗
PubMed1985

Brain manganese accumulation following systemic administration of different forms.

The content and retention of manganese in the blood and brain of mice exposed to different forms of the metal was compared. Mice received an acute sc injection of manganese as the chloride or oxide (Mn3O4) or as the organic MMT. A single injection markedly elevated brain manganese concentrations within 1 day and elevated levels were maintained for at least 21 days. Repeated injections led to further increases in both brain and blood, although the levels in the brain appeared to persist at consistently high levels for longer periods. The chloride form produced higher brain levels than either of the other two forms. These results appear to suggest that the slowly developing neurotoxicity in response to manganese exposure may be due to a persistent retention of manganese by the brain.

Animals↗
PubMed1985

Occupational exposure to mercury in dentistry and pregnancy outcome.

A questionnaire was mailed to dentists and dental assistants requesting information about work, health, and reproductive history. Statistical analysis of the data indicated that there were no increased rates of spontaneous abortions or congenital abnormalities in the children of men and women who were exposed to low versus high levels of mercury in a dental environment.

Abnormalities, Drug-Induced↗
PubMed1985

Colorectal cancer in Chinese and Chinese-Americans.

Rationale and plans are described for a collaborative case-control study of large bowel cancer among Chinese-Americans in Los Angeles and the San Francisco Bay Area and among Chinese in Zhejiang Province, People's Republic of China. A common protocol and questionnaire will be used during personal interviews of approximately 400 Chinese and 300 Chinese-American patients with histologically confirmed adenocarcinoma of the colon or rectum and 2,100 Chinese and Chinese-American controls. Controls will be matched to patients on age, sex, and community of residence. The information requested from subjects will permit testing of hypotheses relating colorectal cancer risk to: dietary factors, including intake of fat (saturated and unsaturated), animal protein, fiber, and vitamins A and E and ascorbic acid; physical activity levels and body mass index; reproductive factors among women; history of bowel disease; and family history of cancer. The information requested of Chinese-American subjects will also permit testing of hypotheses relating cancer risk to such migrant factors as United States versus Chinese nativity, duration of residence in the United States, and Chinese province of ancestry. These factors will be tested for associations with cancers of the colon and rectum separately and with cancers of the large intestine as a whole. We will examine sex and geographic differences in relative risks for etiologic factors, location of tumors within the large bowel, histologic subtype of adenocarcinoma, and frequency of accompanying polyps.

Adult↗
PubMed1983

Why patients return after refraction.

Although nonsurgical ophthalmologic practice depends on refraction, in recent years interest in this procedure has decreased. The ophthalmologist, however, must recognize that a well done refraction builds the patient's confidence and is the basis on which most surgical practices develop.

Aged↗
PubMed1981

Exposure to nitrous oxide and neurologic disease among dental professionals.

Questionnaires, mailed to approximately 30,000 dentists and an equal number of dental assistants requesting information regarding professional exposure to anesthetics and health problems, showed an increased incidence of neurologic complaints in dental professionals who worked with nitrous oxide. The most striking differences were noted in individuals reporting symptoms of numbness, tingling, and/or muscle weakness. For dentists heavily exposed to nitrous oxide, the rate of these complaints was 4-fold greater than for nonanesthetic-exposed dentists. For dental assistants heavily exposed to nitrous oxide, a 3-fold increase in these same complaints was noted. In view of recent evidence that nitrous oxide abuse may lead to polyneuropathy, the results suggest that occupational exposure to nitrous oxide by both dentists and dental assistants may be associated with similar neuropathy.

Adult↗
PubMed1980

Surgery during pregnancy and fetal outcome.

As many as 2% of all pregnant women undergo surgery during gestation, but there are few reports of the effects of anesthesia and surgery on fetal outcome. The present paper presents information on 287 women who had surgery during pregnancy. Surgery during early pregnancy was associated with a significant increase in the rate of spontaneous abortion compared to the rate in a control group that did not have surgery. There were no differences in the incidence of congenital abnormalities in this offspring of women who had surgery during early pregnancy. The data suggest that elective surgery be deferred during early pregnancy to minimize potential fetal loss.

Abortion, Spontaneous↗
PubMed1980

Occupational disease in dentistry and chronic exposure to trace anesthetic gases.

A mail survey of 30,650 dentists and 30,547 chairside assistants grouped according to occupational exposure to inhalation anesthetic and sedatives in the dental operatory indicated increased general health problems and reproductive difficulties among respondents exposed to anesthetics. For male dentists who were heavily exposed to anesthetics, the increase in liver disease was 1.7-fold, kidney disease was 1.2-fold, and neurological disease was 1.9-fold. For wives of male dentists who were heavily exposed to anesthetics, the increase in spontaneous abortion rate was 1.5-fold. Among female chairside assistants who were heavily exposed to anesthetics, the increase in liver disease was 1.6-fold, kidney disease was 1.7-fold, and neurological disease was 2.8-fold. The increase in spontaneous abortion rate among assistants who were heavily exposed was 2.3-fold. Cancer rates in women heavily exposed to inhalation anesthetics were increased 1.5-fold but this finding was not statistically significant (P = .06). Separate analysis of the data for disease rates and birth difficulties by type of inhalation anesthetic indicates that in both dentists and chairside assistants chronic exposure to nitrous oxide alone is associated with an increase rate of adverse response.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Fine needle aspiration cytodiagnosis of liver tumors. Results obtained with Riu's stain.

OBJECTIVE: To present our experience with liver fine needle aspiration (FNA) diagnosis based on Riu's stain. STUDY DESIGN: We reviewed a total of 322 liver fine needle aspirates from 286 patients seen in a seven-year period from April 1990 to April 1997 at Koo Foundation Sun Yat-Sen Cancer Center, Taipei. Surgical and/or clinical follow-up was available for confirmation in 292 aspirates. RESULTS: The cytologic diagnosis was categorized into four groups: benign in 81 cases, suspicious in 13, malignant in 225, and inadequate specimen in 3 cases. There were 16 false negative and no false positive diagnoses. Two suspicious aspirates were negative. Our results showed a sensitivity of 93.3% and a specificity of 100% for the detection of malignancy. If suspicious cases were considered positive, the specificity decreased to 95.1%, while the sensitivity increased to 93.6%. Among 87 hepatocellular carcinomas (HCCs) in our series, correct FNA diagnosis was made in 84 cases with an accuracy of 96.6%. Out of 135 cases of non-HCCs, 1 was incorrectly diagnosed. The accuracy of identifying a liver malignancy as non-HCC was 99.3%. CONCLUSION: Cytologic features of HCC are well demonstrated by Riu's stain, with high accuracy in identifying them. Liver FNAs using Riu's stain combined with cell block study and clinicopathologic correlation can achieve very high sensitivity and specificity in the detection of hepatic malignancies.

Adenocarcinoma↗