Biomedical subjects

Yan Jin

Publications and source records attributed to Yan Jin.

140 records · Page 8Linked to original sources

PubMed2002

Influence of aboriginal and socioeconomic status on birth outcome and maternal morbidity.

OBJECTIVE: To assess the association of Aboriginal and socioeconomic status with birth outcome and maternal morbidity in Alberta. METHODS: A retrospective cohort study using Alberta health service and vital statistics data from 1997 to 2000. Aboriginal women registered with the Department of Indian and Northern Development (DIAND) were linked to a personal health number. Low socioeconomic status was defined as either receiving subsidization for the Alberta Health Care Insurance premium or receiving welfare. RESULTS: Women registered with DIAND and women receiving subsidy or welfare were younger, more often unmarried, smoked more, consumed more alcohol, and abused more illicit drugs than other women in Alberta during the time period studied. Fewer women registered with DIAND and women receiving subsidy or welfare had physician prenatal visits, attended prenatal classes, had forceps or vacuum deliveries, and more of these women frequently had gestation ages less than 37 weeks. Women registered with DIAND had more deliveries in smaller, non-metropolitan facilities; and more of these women delivered outside their region of residence; more had longer lengths of hospital stay; more mothers and neonates were re-admitted to hospital within 28 days of discharge after delivery; fewer delivered small for gestational age neonates; fewer delivered neonates with birth weight less than 2500 g, but more delivered neonates with birth weight greater than 4000 g. There were fewer Caesarean sections in women registered with DIAND (OR = 0.84, 95% CI 0.76-0.93) and in women receiving subsidy or welfare (OR = 0.88, 95% CI 0.82-0.93). CONCLUSION: Women receiving subsidy or welfare and women registered with DIAND had many demographic similarities and generally had worse maternal and neonatal outcomes than other women in Alberta. Medical system interaction may be different for these two groups of women than it is for other women in Alberta.

Adolescent↗

PubMed2002

Follicle-stimulating hormone is indispensable for the last spermatogonial mitosis preceding meiosis initiation in newts (Cynops pyrrhogaster).

We previously reported that mammalian FSH induced differentiation of secondary spermatogonia into primary spermatocytes in organ culture of newt testicular fragments, whereas in medium lacking FSH primary spermatocytes never appeared. Here, we investigated why spermatogonia fail to form primary spermatocytes in the absence of FSH. Spermatogonia maintained proliferative activity and viability at about half the level of those cultured in the presence of FSH, progressed into the seventh generation, but became moribund during the G2/M phase. Thus, the eighth generation of spermatogonia never appeared, suggesting that cell death is the chief reason why primary spermatocytes fail to form in the absence of FSH. The presence of Dmc1, a molecular marker for the spermatocyte stage, confirmed our microscopic observations that spermatogonia differentiated into primary spermatocytes in the presence of FSH. Thus, FSH is indispensable for the completion of the last spermatogonial mitosis, a prerequisite for the conversion of germ cells from mitosis to meiosis. Because prolactin induced apoptosis in spermatogonia during the seventh generation, we propose that a checkpoint exists for the initiation of meiosis in the seventh generation whereby spermatogonia enter meiosis when the concentration ratio of FSH to prolactin is high but fail to do so when the ratio is low.

Animals↗

PubMed2002

Acute protection of ischemic heart by FGF-2: involvement of FGF-2 receptors and protein kinase C.

We examined the effect of fibroblast growth factor (FGF)-2 on myocardial resistance to injury when administered after the onset of ischemia, in vivo and ex vivo, and the role of FGF-2 receptors and protein kinase C (PKC). FGF-2 was injected into the left ventricle of rats undergoing permanent surgical coronary occlusion leading to myocardial infarction (MI). After 24 h, FGF-2-treated hearts displayed significantly reduced injury, determined by histological staining and troponin T release, and improved developed pressure compared with untreated controls. An FGF-2 mutant with diminished affinity for the tyrosine kinase FGF-2 receptor 1 (FGFR1) was not cardioprotective. FGF-2-treated hearts retained improved function and decreased damage at 6 wk after MI. In the ex vivo heart, FGF-2 administration during reperfusion after 30-min ischemia improved functional recovery and increased relative levels of PKC subtypes alpha, epsilon, and zeta in the particulate fraction, in a chelerythrine-preventable mode; it also decreased loss of energy metabolites. We conclude that intramyocardial FGF-2 administration shortly after the onset of ischemia confers protection from acute and chronic cardiac dysfunction and damage; FGF-2 delivered during reperfusion protects from ischemia-reperfusion injury; and protection by FGF-2 requires intact binding to FGFR1 and is likely mediated by PKC.

Animals↗

PubMed2002

Low-volume obstetrics. Characteristics of family physicians' practices in Alberta.

OBJECTIVE: To compare the obstetric practices of family physicians who attended fewer than 25 births per year (low-volume) with the practices of family physicians who attended more than 25 births per year (high-volume) and the practices of obstetricians. DESIGN: Retrospective cohort study using data from administrative databases. SETTING: Alberta. PARTICIPANTS: All physicians who provided intrapartum care between April 1, 1997, and March 31, 2000. MAIN OUTCOME MEASURES: Type of delivery, size of hospitals where deliveries took place, characteristics of patients, and number of medical interventions. RESULTS: Of 1026 family physicians, 543 (53%) were low-volume providers of intrapartum care. In 1997-1998, low-volume family physicians (LVFPs) attended 24% of all vaginal and cesarean births attended by family physicians; by 1998-1999, that percentage had decreased to 9%; and by 1999-2000, to 5%. In contrast, the number of births attended by all family physicians remained relatively constant at 43% during the 3 years. In hospitals that had fewer than 50 deliveries a year, LVFPs attended almost half the births. Although LVFPs did fewer medical inductions, vacuum extractions, and epidural anesthetics and more forceps extractions, episiotomies, and cesarean sections than high-volume family physicians (HVFPs), the differences between their practices were much smaller than the differences between all family physicians' practices and the practices of obstetricians (who treat higher-risk mothers and newborns). CONCLUSION: The decrease in LVFPs' obstetric practices could make a pronounced difference at smaller hospitals where most low-volume practice occurs.

Alberta↗

PubMed2001

Inhibition of Scavenger Receptor A Expression Treated with PMA by the Inhibitor of Tyrosine Protein Kinase Genistein.

In order to investigate the relationship between scavenger receptor type A and cell signal transduction, human U937 macrophages were treated with tyrosine protein kinase inhibitor genistein, then the cells were incubated with [(125)I]ox-LDL or ox-LDL, and the cellular degradation of [(125)I]ox-LDL or binding were measured separately. Then the effect of the drug on cell surface expression of SR-A were measured by means of autoradiography, it was found that genistein could reduce cellular SR-A mRNA transcription by RT-PCR. The results indicated that genistein could reduce U937 macrophages to bind lipids and reduce SR-A expression by suppression of transcription, and could reduce degradation of lipids by U937 macrophage and accumulation of cholesterol within the cells. It suggests that the function of scavenger receptors may be correlated with cell tyrosine protein kinase, the mechanism is transcriptional and it also suggests that SR-A may participate in the signal transduction directly.

Journal Article↗

PubMed1999

Effect of Protein Kinase C Inhibitor on Scavenger Receptor in Human U937 Macrophage-like Cells.

In order to investigate effects of cell protein phosphorylation on scavenger receptor, human U937 macrophage-like cells were treated with protein kinase C inhibitor staurosporine, then the cells were incubated with (125)I ox-LDL or ox-LDL, and the cellular degradation of (125)I ox-LDL, its binding to receptor and the internalization of cell surface ox-LDL receptor complex as well as the accumulation of lipids within cells were measured separately. Moreover, the effects of the drug on expression of cell surface receptor were observed by means of autoradiography. The results indicated that staurosporine could enhance U937 cells to bind lipids and stimulate scavenger receptor expression, and could reduce degradation of lipids by U937 cells and the accumulation of cholesterol within the cells. It suggests that the function of scavenger receptors may be correlated with cell protein phorsphorylation.

Journal Article↗

PubMedDate not supplied

Genetic spatial clustering: significant implications for conservation of wild soybean (Glycine soja: Fabaceae).

Knowledge of spatial patterns of genetic variation within populations of wild relative species has significant implications with respect to sampling strategies for ex situ and in situ conservation. To study spatial genetic structure of wild soybean (Glycine soja Sieb. et Zucc.) at the fine scale, three natural populations in northern China were analyzed using inter-simple sequence repeat (ISSR) fingerprints for estimating kinship coefficients. A regression analysis of kinship coefficients against spatial distances revealed that individuals occurring close together tended to be more genetically related. The Sp statistic further indicated a comparable spatial pattern among the three wild soybean populations with similar Sp values (mean = 0.0734, varied from 0.0645 to 0.0943) detected across the three populations. Genetic patches were on average ca. 20 m in size, and the effective neighborhood sizes varied between 10 and 15 m. The spatial genetic structure evident in the wild soybean populations may be attributed to the restricted seed dispersal and predominant inbreeding mating system of this species. The detection of family structure in the populations of wild soybean has a significant implication for the effective conservation of the important genetic resources.

Breeding↗

PubMedDate not supplied

Hospitalization for community-acquired pneumonia in Alberta patients with human immunodeficiency virus infections: a case control study.

BACKGROUND: To determine whether outcomes of pneumonia among human immunodeficiency virus (HIV)-positive persons differed from those among HIV-negative persons. METHODS: Alberta hospital patient abstracts for HIV-positive per-sons requiring hospitalization for pneumonia from April 1, 1994,until March 31, 1999, were matched by age and sex with four HIV-negative counterparts. RESULTS: Hospitalizations for community-acquired pneumonia decreased for those with HIV (acquired immunodeficiency syndrome[AIDS]) and increased for those with HIV (non-AIDS) during the study period. HIV (AIDS) patients admitted for community-acquired pneumonia (n=130) manifested three times higher odds for a longer length of hospital stay and had three and 10 times higher odds for excess in-hospital and one-year mortality, respectively, than their matched controls. Similarly, HIV (non-AIDS) patients admitted for community-acquired pneumonia (n=46) manifested two times high-er odds for a longer length of hospital stay and had four times higher odds for excess one-year mortality than their matched controls. The in-hospital and one-year mortality rates for the HIV (AIDS) patients were 21.2% and 64.3%, respectively, during the first three years, and decreased to 8.7% and 40.7%, respectively, in the last two years of the study. CONCLUSIONS: The outcomes for community-acquired pneumonia were worse for those with HIV (non-AIDS) and HIV (AIDS)compared with non-HIV hospitalized patients matched for age and sex, and controlling for severity of illness and comorbidity. In-hospital and one-year mortality rates for patients with HIV (AIDS)showed a marked decline over the study period.

Alberta↗

PubMedDate not supplied

Hospitalization for community-acquired pneumonia in Alberta First Nations Aboriginals compared with non-First Nations Albertans.

BACKGROUND: The rates and outcomes of hospital admission for community-acquired pneumonia between First Nations Aboriginal and non-First Nations groups were compared. METHODS: Alberta administrative hospital abstracts from April 1, 1997, to March 31, 1999, were analyzed, and each case of a First Nations Aboriginal person with pneumonia was matched by age and sex with three non-First Nations persons with pneumonia. RESULTS: The First Nations Aboriginal age and sex-adjusted hospital discharge rate was 22 per 1000 (95% CI 20.7 to 23.6) compared with 4.4 per 1000 (95% CI 4.4 to 4.5) for the general population of Alberta. After accounting for comorbidity and severity of pneumonia, in-hospital mortality and hospital length of stay were lower for First Nations Aboriginals compared with the matched non-First Nations group (odds ratio 0.49; 95% CI 0.37 to 0.66, and odds ratio 0.87; 95% CI 0.79 to 0.97, respectively). The odds for 30-day hospital readmission were higher in First Nations Aboriginals compared with the non-First Nations group (odds ratio 1.42; 95% CI 1.21 to 1.68). The cost per hospital admission for First Nations Aboriginals was 94% of the average cost for the matched non-First Nations group (CDN4,206 dollars). However, their median daily cost was 1.25 times higher (95% CI 1.14 to 1.36) than the matched non-First Nations group. CONCLUSIONS: First Nations Aboriginals had higher rates of hospitalization, rehospitalization and hospital costs for community-acquired pneumonia than non-First Nations Albertans. It was unlikely that the high rate of hospitalizations in First Nations Aboriginals was due to more severe pneumonia or greater comorbidity. Other unexplained factors increase the burden of this disease in First Nation Aboriginals.

Adult↗

PubMedDate not supplied

Effect of soil properties on saturated and unsaturated virus transport through columns.

Viruses from contaminant sources can be transported through porous media to drinking water wells. The objective of this study was to investigate inactivation and sorption of viruses during saturated and unsaturated transport in different soils. Bacteriophages phiX174 and MS-2, and Br- tracer in a phosphate-buffered saline solution were introduced into saturated and unsaturated soil columns as a step function under constant flow rate and hydraulic conditions. Results showed that significantly greater virus removal occurred in the unsaturated columns than in the saturated columns in the two soils containing high metal oxides content. However, the increase in virus retention under unsaturated conditions was not significant in two other soils having high phosphorus and calcium contents and high pH, and in another soil with high organic matter content. The results imply that the extent of water content effect on inactivation and sorption of viruses can range from significant to minimal depending on the properties of the transport medium. We found that the presence of in situ metal oxides was a significant factor responsible for virus sorption and inactivation. Therefore, soils with high metal oxides content may have the potential to be used as hydrological barriers in preventing microbial contamination in the subsurface environments. We also found that the water content effect on virus removal and inactivation strongly depended on solid properties of the testing medium.

Adsorption↗

PubMedDate not supplied

Sorption of MS2 bacteriophage to layered double hydroxides: effects of reaction time, pH, and competing anions.

Batch sorption and column breakthrough studies were conducted to investigate the potential of layered double hydroxides (LDHs) to remove bacteriophage MS2 from contaminated waters. All four of the LDHs evaluated in this study had very high retention capacities for MS2. Sorption results showed that MS2 could be completely removed from 5.2 x 10(2) plaque-forming units (pfu)/mL solution by Mg-Al LDH 2 (i.e., 2:1 Mg to Al ratio LDH), with the highest sorption capacity observed in this study of 1.51 x 10(10) pfu/g. Attachment of MS2 to LDHs was a rapid process and reached quasi-equilibrium after a 1-h reaction time. Within the pH range studied (pH 4-9), Mg-Al LDH 2 showed high sorption potential for MS2 at all pH values but sorption decreased slightly with increasing solution pH. Background solution anions influenced virus sorption, with SO4(2-) and HPO4(2-) decreasing sorption significantly whereas the presence of NO3- had little effect on the attachment of MS2 to Mg-Al LDH 2. The addition of another virus (phiX174) only caused a slight decrease in the retention of MS2 by Mg-Al LDH 2, suggesting that there was insignificant competitive sorption between MS2 and phiX174 on LDH surfaces. Results from column experiments indicate that there was no MS2 breakthrough from columns packed with Mg-Al LDH 2-coated sand, suggesting complete MS2 retention at the virus concentration tested. The high mass recovery by beef extract solution revealed that the removal of viruses by the LDH was due to sorption of MS2 to LDH surfaces, rather than inactivation.

Adsorption↗

PubMedDate not supplied

Virus retention and transport as influenced by different forms of soil organic matter.

Organic materials are widespread in natural soil and aquatic environments. Their effect on virus transport is very important in assessing the risk for contamination of ground water by viruses. This study aimed to determine how different forms (mineral-associated and dissolved) of natural organic matter influence the retention and transport of two bacteriophages (MS-2 and phiX174) in two porous media (a sand and a soil). We found that mineral-associated organic matter significantly promoted the transport of one virus (MS-2) but not the other (phiX174) in a phosphate-buffered saline solution. Similarly, MS-2 was retained less in sand columns with increasing concentrations of dissolved humic acid, while little effect was observed for phiX174 under the same conditions. The two viruses have different surface properties and thus exhibited different reactivity to the metal oxides present on sand particles and were affected differently by organic matter. Because the organic matter used in the study was negatively charged and hydrophilic, blocking of virus sorption sites and increasing of virus-medium electrostatic repulsion arising from modification of the sand and virus surface by organic matter are probably responsible for the facilitated transport. For dissolved humic acid, its competition for sorption sites with viruses was an additional mechanism involved. This study suggests that the effect of organic matter varied depending on the organic material properties and the type of viruses involved. As a general trend, the effect of organic matter was dominated by electrostatic rather than hydrophobic interactions.

Adsorption↗

PubMedDate not supplied

Early discharge of Alberta mothers post-delivery and the relationship to potentially preventable newborn readmissions.

OBJECTIVE: To determine whether early maternal discharge increases newborn readmission rates. METHODS: Singleton vaginal deliveries weighing at least 2500 grams were extracted from April 1, 1997 to March 31, 2000 Alberta hospital abstracts and linked to records of birth. Potentially preventable readmissions were for dehydration, jaundice, feeding problems, inadequate weight gain, and social reasons. RESULTS: The most common reason for readmission is jaundice (74%). In order of importance, influencing factors were: length of gestation, Aboriginal treaty status, first live birth, delivering in region of residence, number of deliveries done in the hospital, newborn sex, maternal smoking, birthweight, previous abortions, and delivering in nearest hospital. Post-delivery length of stay was associated with readmissions in the first 6 days post discharge (25% greater in those < 27 hours compared to those > 48 hours) but not in the first 28 days post discharge. CONCLUSION: Early maternal discharge is a minor determinant of potentially preventable newborn readmissions.

Adolescent↗

PubMedDate not supplied

The association between influenza immunization coverage rates and hospitalization for community-acquired pneumonia in Alberta.

BACKGROUND: We compared regional coverage rates of influenza vaccination (composition in 1999/00 was A/Sydney-like A/Beijing-like B/Yamanashi-like and in 2000/01 was A/Moscow A/New Caledonia B/Beijing) to the rates, cost, and mortality for community-acquired pneumonia. METHODS: We used the Pearson's correlation coefficient to establish linear associations between variables derived from Alberta administrative data during the period April 1, 1999 to March 31, 2001. RESULTS: The influenza vaccination coverage rate for the 17 health regions varied between 30% to 80% (mean 70%) in Alberta seniors (n=298,473). The annual hospitalization and ambulatory community-acquired pneumonia attack rates were 2% and 6.5% per year respectively. There were strongly negative correlations between vaccination coverage rates and pneumonia rates requiring hospitalization (r1999=-0.59 and r2000=-0.79 with both p<0.05), total per capita physician and hospital costs for pneumonia (r1999=-0.57 and r2000=-0.79 with both p<0.01), community-diagnosed pneumonia rate (r1999=-0.39, p=0.12 and r2000=-0.70, p<0.01) and per capita in-hospital mortality for pneumonia (r1999=-0.30, p=0.24 and r2000=-0.57, p<0.05). Per capita costs, rates, and mortality were highest and influenza vaccinations rate lowest in the northern, remote health regions. The per capita vaccination cost (about 10 dollars) was small in relationship to the per capita cost of hospital care for pneumonia (about 100 dollars). CONCLUSION: Regional under-utilization of preventive influenza vaccination in Alberta seniors is associated with increased utilization of health services for community-acquired pneumonia.

Aged↗