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Biomedical subjects

Y Mao

Publications and source records attributed to Y Mao.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

A genetic study of the human low-voltage electroencephalogram.

The studied phenotype, the low-voltage electroencephalogram (LVEEG), is characterized by the absence of an alpha rhythm from the resting EEG. In previous studies, evidence was found for a simple autosomal-dominant mode of inheritance of the LVEEG. Such a polymorphism in brain function can be used as a research model for the stepwise elucidation of the molecular mechanism involved in those aspects of neuronal activity that are reflected in the EEG. Linkage with the variable number of tandem repeats (VNTR) marker CMM6 (D20S19) and localization of an LVEEG (EEGV1) gene on 20q have previously been reported, and genetic heterogeneity has been demonstrated. This latter result has been corroborated by studying new marker (MS214). The phenotype of the LVEEG is described here in greater detail. Its main characteristic is the absence of rhythmic alpha activity, especially in occipital leads, whereas other wave forms such as beta or theta waves may be present. Analysis of 17 new families (some of them large), together with 60 previously described nuclear families, supports the genetic hypothesis of an autosomal-dominant mode of inheritance. Problems connected with the analysis of linkage heterogeneity, exclusion mapping, and the study of multipoint linkage are discussed. A possible explanation of the localization of LVEEG in the close vicinity of another gene influencing synchronization of the normal EEG, the gene for benign neonatal epilepsie, is given.

Aging↗
PubMedDate not supplied

Cervical cancer in Canada: changing patterns in incidence and mortality.

Data on incidence of cervical cancer by histologic subtype and mortality for the Canadian provinces of Ontario, Saskatchewan, and British Columbia were used to examine time trends by age, calender period, and birth cohort. Age-adjusted incidence rate of squamous cell carcinoma of the cervix decreased from 11.1 per 100,000 women in 1970-72 to 5.3 in 1994-96, while the rate for cervical adenocarcinoma increased from 1.1 per 100,000 women to 1.5 over the same period. Age-adjusted mortality rate declined from 7.9 per 100,000 women in 1953-55 to 1.9 in 1995-97. The patterns in age-specific mortality rates in 1953-72 were different from those in 1973-97; younger women experienced larger reductions in mortality during the earlier period while older women benefited to a greater extent during the latter period. Age-period-cohort modeling showed that cohort effects were responsible for the decreasing trends in incidence of squamous cell carcinoma of the cervix and increasing trends in adenocarcinoma, and both period and cohort effects account for the observed trends in mortality. The results suggest that Pap smear screening has played a significant role in the reduction in squamous cell cervical carcinoma. The causes for the increase in cervical adenocarcinoma are unclear.

Adenocarcinoma↗
PubMedDate not supplied

Fluoride in plaque fluid, plaque, and saliva measured for 2 hours after a sodium fluoride monofluorophosphate rinse.

Sodium monofluorophosphate (NaMFP) and sodium fluoride (NaF) are the two most common sources of fluoride used in currently marketed fluoride dentifrices. The purpose of this study was to investigate the effect of mouth rinses containing NaF or NaMFP on the concentrations of fluoride, or the MFP ion, in saliva, whole plaque, and plaque fluid. Twelve subjects abstained from tooth brushing for 48 h, fasted overnight, and then rinsed 1 min with 12 mmol/l (228 ppm [microg/g] F) NaF or NaMFP in the morning. Before the rinse and at 30, 60 and 120 min afterwards, upper and lower molar and premolar plaque samples and whole saliva samples were collected. Aliquots of plaque fluid and centrifuged saliva were obtained from these samples, and the whole plaque residue acid extracted. The F and MFP concentrations were then measured in these samples using ultramicro methods. For both rinses, a higher concentration of plaque fluid fluoride was found at lower molar sites while the reverse was true for the whole plaque fluoride. Furthermore, for both rinses, plaque fluid, whole plaque, but not salivary, fluoride concentrations were above baseline at 120 min. Following the NaMFP rinse, a substantial amount of unhydrolyzed MFP was found in plaque fluid and saliva. Although there was a very large range in these measurements, fluoride in plaque fluid (excluding fluoride in unhydrolyzed MFP) and whole plaque were significantly (p<0.05) greater after the NaF rinse at all time periods. In saliva, the NaF rinse produced a statistically significant greater salivary fluoride (excluding fluoride in unhydrolyzed MFP) only at 60 min. The lack of a clear correlation between these measurements and clinical studies suggest a novel mechanism may enhance the effectiveness of NaMFP dentifrices.

Adult↗
PubMedDate not supplied

Birth cohort effects underlying the increasing testicular cancer incidence in Canada.

PURPOSE: To examine the pattern of testicular cancer incidence by age, time period and birth cohort since 1969 in Canada. METHODS: In addition to analyses of the secular trends by age group and birth cohort separately, an age-period-cohort model and the submodels with standard Poisson assumptions were fitted to the data. RESULTS: The overall age-adjusted incidence of testicular cancer increased in Canada, from 2.8 per 100,000 males in 1969-71 to 4.2 in 1991-93. The younger age groups showed much higher absolute incidence rates in the recent period compared with those in the early period. Age-period-cohort modelling of data restricted to males aged 20-84 years suggested that the observed increase in testicular cancer could be largely attributed to a birth cohort effect. A steady increase in risk was observed among men born since 1945; those born between 1959 and 1968 were 2.0 (95% CI, 1.5-2.6) times as likely to develop testicular cancer as those born between 1904 and 1913. CONCLUSION: The risk of testicular cancer has increased over time and changing exposure to environmental factors early in life may be responsible for this.

Adolescent↗
PubMedDate not supplied

Time trends and sex patterns in Hodgkin's disease incidence in Canada, 1970-1995.

PURPOSE: To examine time trends and sex patterns in Hodgkin's disease incidence in Canada, from 1970 through 1995. METHOD: In addition to analyses of the secular trends and sex ratio in incidence rates, age-period-cohort models were fitted to estimate the effects on the trends. Age-specific male/female incidence rate ratios were examined for the disease and for its two major histologic subtypes. RESULTS: The overall age-adjusted incidence rate of Hodgkin's disease decreased significantly in males (3.5 per 100,000 in 1970-71 to 2.8 in 1994-95) but only slightly in females (2.4 per 100,000 to 2.3). There was a significant increase in the incidence among females aged 10-29 and among males aged 10-24, but a dramatic decrease among older ages. Age-period-cohort modelling showed that birth cohort and period effects were responsible for the observed trends in males and females, respectively. CONCLUSION: The risk factors responsible for Hodgkin's disease are different in females and males. Reproductive factors are likely to be associated with the occurrence of the disease in young women.

Adolescent↗
PubMedDate not supplied

A new cell proliferating marker: cytosolic thymidine kinase as compared to proliferating cell nuclear antigen in patients with colorectal carcinoma.

BACKGROUND: Proliferation markers are necessary for reliable diagnosis. Here we have presented for the first time thymidine kinase 1 (TK1) as a proliferative tumor marker for colorectal carcinoma. PATIENTS AND METHODS: Expression of TK1 in 54 colorectal lesions and 20 colorectal adenoma lesions was detected by immunohistochemistry technique (ABC). Proliferating Cell Nuclear Antigen (PCNA) was run in parallel. RESULTS: TK1-Labelling Index (LI) (65%) was higher than PCNA-LI (52%) in the malignant lesions, although not significantly different (p = 0.1717) between them. TK1-LI as well as PCNA-LI showed significant differences between colorectal carcinoma and colorectal adenoma (TK1 p = 0.0005, PCNA p = 0.0005). Both TK1-LI and PCNA were significantly different in respect to tumor stages (TK1 p = 0.0002, PCNA p = 0.0284). However, only TK1-LI showed significant difference in respect to tumor grades (p = 0.014), but not PCNA-LI (p = 0.132). CONCLUSION: TK1-LI showed more potential as a proliferating marker in colorectal carcinoma than PCNA-LI, especially for evaluating high-risk tumor grade and advanced stage in colorectal carcinoma.

Adenocarcinoma, Papillary↗
PubMedDate not supplied

PM-3, a benzo-gamma-pyran derivative isolated from propolis, inhibits growth of MCF-7 human breast cancer cells.

Propolis has numerous biologic activities including antibiotic, antifungal, antiviral and anti-inflammatory properties. Several components isolated from propolis have been shown to have anticancer activity. This study demonstrates that the compound PM-3 (3-[2-dimethyl-8-(3-methyl-2-butenyl)benzopyran]-6-propenoic acid) isolated from Brazilian propolis markedly inhibits the growth of MCF-7 human breast cancer cells. This effect was associated with inhibition of cell cycle progression and induction of apoptosis. Treatment of MCF-7 cells with PM-3 arrested cells in the G1 phase and resulted in a decrease in the protein levels of cyclin D1 and cyclin E. PM-3 also inhibited the expression of cyclin D1 at the transcriptional level when examined in cyclin D1 promoter luciferase assays. Induction of apoptosis by PM-3 occurred within 48 hours after treatment of MCF-7 cells. The MCF-7 treated cells also displayed a decrease in the level of the estrogen receptor (ER) protein and inhibition of estrogen response element (ERE) promoter activity. Therefore, PM-3 merits further investigation with respect to breast cancer chemoprevention or therapy.

Annexin A5↗
PubMedDate not supplied

The impact of the decreased prevalence of smoking in Canada.

Using data on the prevalence of smoking among different age and gender groups, we estimated the impact of the prevalence of smoking on the present and future mortality of Canadians. In 1989, the life expectancy of male smokers at the age of 45 was 7 years less than non-smokers, among female smokers life expectancy was 4 years less than non-smokers. The total number of smoking-attributable deaths from all causes was estimated for every decade from 1969 to 2019. A decrease in smoking prevalence from 1989 levels to 10% overall in 1999 would result in 15,000 and 6,000 fewer smoking-attributable deaths among women and men, respectively. Continuing the existing pattern of smoking among men and women will result in an increase in the total number of smoking-attributable deaths among women and an increase in the smoking-attributable deaths from lung cancer in both sexes.

Adolescent↗
PubMedDate not supplied

Indian Reserve and registered Indian mortality in Canada.

Although in demand, there is only limited information available regarding the patterns of mortality among Natives in Canada. Mortality rates for residents of Canadian Indian Reserves (IRs) and Registered Indians were calculated for the periods 1979-1988 and 1981 respectively. Proportionate mortality ratios and age-standardized mortality rates for residents of Indian Reserves were similar to those obtained for Registered Indians. Standardized mortality ratios were calculated using both Canadian mortality and mortality in selected isolated rural populations as references. Dramatically increased risks were observed among Native populations for mortality from alcoholism/liver cirrhosis, homicide, suicide and pneumonia. While SMRs calculated using mortality rates in rural populations appeared to be preferable to those using Canadian rates, the use of Canadian rates does not alter the conclusion that IRs have significantly elevated mortality from environmental and social causes which, although improving, require continuing control efforts.

Adolescent↗
PubMedDate not supplied

[Identification of a novel human MAST4 gene, a new member of the microtubule associated serine-threonine kinase family].

Human protein kinases make up a large superfamily of homologous proteins, which are related by virtue of their kinase domains (also known as catalytic domains). Here we report the cloning and characterization of a novel human MAST4 (microtubule associated serine/threonine kinase family member 4) gene, which locates on human chromosome 5q13. The MAST4 cDNA is 7587 base pairs in length and encodes a putative protein of 2435 amino acids which contains a serine/threonine kinase domain and a PDZ domain. MAST4 protein has 64%, 63%, 59% and 39% identical aminoacid residues with MAST1, MAST2, MAST3 and MASTL respectively. RT-PCR analysis revealed relatively high expression level of MAST4 in most normal human tissues, with an exception of in testis, small intestine, colon and peripheral blood leukocyte.

Amino Acid Sequence↗
PubMedDate not supplied

Long-term survival rates among patients with cancer in Saskatchewan, 1967-1986.

We calculated relative survival rates from 5 to 15 years after diagnosis for cancer cases diagnosed in Saskatchewan, Canada, between 1967 and 1986. Cancers with high 15-year relative survival (greater than 60%) included lip, melanoma among women, other male genital sites, and corpus uteri. As anticipated, relative survival rates declined with increasing length of follow-up, with the largest relative declines noted among those in the oldest age group (65+ years). Only small declines in relative survival were noted for cancers of the colon and cervix with increasing length of follow-up. Improved survival of cases diagnosed in the period 1980-1984 compared to 1970-1974 was observed for all sites combined, as well as the following sites: colon, lung, prostate, brain, ill-defined sites, non-Hodgkin's lymphoma, and lymphoid leukemia. For colorectal cancer, stage at diagnosis was a more important independent predictor of survival than age.

Adult↗
PubMedDate not supplied

Mortality study of Canadian male farm operators: cancer mortality and agricultural practices in Saskatchewan.

The present investigation involved an analysis of approximately 70,000 male Saskatchewan farm operators, a subset of the 365,000 Canadian farm operators to be investigated in the Canadian Farm Operator Mortality Study. The results of the Saskatchewan analysis indicate that during the interval studied, overall mortality among Saskatchewan farmers was 25% lower than that for all Saskatchewan men, and that, during the same time interval, the risk of death from all types of cancer was also about 25% lower among Saskatchewan farmers than to all Saskatchewan men. Although the present study indicates that overall mortality of death from cancer was 25% lower among Saskatchewan male farmers, there was a relationship between non-Hodgkin's lymphoma mortality and acres sprayed for weeds; a similar risk relationship between expenditures on fuel oil and risk of death from non-Hodgkin's lymphoma was also evident. The magnitude of risk for Saskatchewan farmers is probably greater than that reflected in the estimates in this study, due to the likelihood of misclassification of exposure. There is a particular need for further studies in this area to improve the quantification of farming-related exposures, and to study the exposure history of individuals who develop non-Hodgkin's lymphoma.

Adult↗
PubMedDate not supplied

A telephone survey to measure risk factor prevalence in communities across Canada.

From 1985 to 1988, 10 Canadian community health units, in conjunction with Health and Welfare Canada, conducted a standardized telephone survey to assess the prevalence of health risk factors among persons aged 15 and over. Seatbelt use, hypertension awareness, physical activity, smoking, alcohol use, cancer screening status and sociodemographic variables were ascertained in each community. Although prevalence rates for most of the major risk factors varied significantly among the survey communities, little clustering of high or low risk levels was observed in any particular locale. Periodic administration of the risk factor survey in communities across Canada would provide a valuable data base for both public health planners and researchers.

Adolescent↗
PubMedDate not supplied

Suicide in Canada: an epidemiological assessment.

Suicide rates in Canada rapidly increased during the 1960s and 1970s. More recent analysis of these trends indicates that in males suicide rates have stabilized and in females a notable decrease has been identified. The greatest changes in suicide rates have occurred among the youngest age groups (15 to 19), while little change has occurred in suicide mortality rates for males aged 50 years and over. The age-specific death rates in 1986 are uniformly distributed in males above age 20, while in females an inverted "U" curve is demonstrated with the peak at age 45-50. Males continue to have higher rates and the difference between males and females is expanding. A birth cohort analysis indicates that the contribution of the birth cohort to explaining suicide rates has diminished and been replaced by a more recent period effect. Suicide remains the second most important cause of death of persons between 15 and 34 years of age. Provincial variation is discussed through geographic variation, cause-specific rankings and potential years of life lost. In contrast to national trends, suicide mortality in Alberta, Quebec and New Brunswick continues to increase. An atlas is provided to display Canadian census divisions that exhibit elevated rates of suicide.

Adolescent↗
PubMedDate not supplied

Effects of residential exposure to environmental tobacco smoke on Canadian children.

The effects of residential exposure to environmental tobacco smoke were studied in a sample of 6,529 Canadian children under 15 years of age. Univariate analysis indicated an elevated risk of bronchitis among children whose mothers were single, or under age 25, or whose income or educational level was low. Multivariate analysis indicated that the relative risk of bronchitis among children whose mothers were current smokers relative to those whose mothers never smoked was 3.0 (95% CI:1.6,5.2). Significant dose-response relationships between risk of bronchitis and amount smoked as well as duration of exposure were observed. Using the composite exposure score of all smokers in the household as the source of exposure, the risk of bronchitis decreased slightly but remained significantly elevated. Examination of the risk conferred by the mother's smoking relative to the total household exposure showed that most of the elevation in risk was associated with the mother's smoking contribution. Asthma was also studied, but failed to show a statistically significant association with smoking.

Adolescent↗