Education, perceived discrimination and risk for depression in a southern black cohort

Objectives: Assess whether education moderates associations between discrimination and depression risk within a southern Black/African American cohort in a labor market shifting from manufacturing and farming to education-intensive industries, such as health care and technology.Methods: Data are from the Pitt County (NC) Study (n = 1154) collected in 2001. Depression risk was assessed with the Center for Epidemiologic Study-Depression (CES-D) scale. Discrimination was measured using a subset from the Everyday Discrimination Scale. Education was categorized as completion of less than high school (HS), HS/GED (General Educational Development), or any college.Results: Completing any college mitigated the association between discrimination and CES-D among men (b = -1.33, 95% CI = -2.56, -0.09) but not women (b = -0.19, 95% CI = -1.36, 0.98).Conclusions: Education is protective for depression risk related to discrimination for men but not women. Recent macroeconomic changes placed a premium on higher levels of education in 2018, as in the 1990s. Because racial discrimination remains a stressor in the everyday lives of African Americans regardless of education level, the health benefits of higher education for working-aged African Americans in shifting labor markets warrants further investigation.

Visualising coordination chemistry: fluorescence X-ray absorption near edge structure tomography

Here we develop a measurement scheme to determine the abundance, distribution, and coordination environment of biological copper complexes in situ, without need for complex sample preparation.

X-ray fluorescence imaging reveals subcellular biometal disturbances in a childhood neurodegenerative disorder

Biometals such as zinc, iron, copper and calcium play key roles in diverse physiological processes in the brain, but can be toxic in excess. A hallmark of neurodegeneration is a failure of homeostatic mechanisms controlling the concentration and distribution of these elements, resulting in overload, deficiency or mislocalization. A major roadblock to understanding the impact of altered biometal homeostasis in neurodegenerative disease is the lack of rapid, specific and sensitive techniques capable of providing quantitative subcellular information on biometal homeostasis in situ. Recent advances in X-ray fluorescence detectors have provided an opportunity to rapidly measure biometal content at subcellular resolution in cell populations using X-ray Fluorescence Microscopy (XFM). We applied this approach to investigate subcellular biometal homeostasis in a cerebellar cell line isolated from a natural mouse model of a childhood neurodegenerative disorder, the CLN6 form of neuronal ceroid lipofuscinosis, commonly known as Batten disease. Despite no global changes to whole cell concentrations of zinc or calcium, XFM revealed significant subcellular mislocalization of these important biological second messengers in cerebellar Cln6nclf (CbCln6nclf ) cells. XFM revealed that nuclear-to-cytoplasmic trafficking of zinc was severely perturbed in diseased cells and the subcellular distribution of calcium was drastically altered in CbCln6nclf cells. Subtle differences in the zinc K-edge X-ray Absorption Near Edge Structure (XANES) spectra of control and CbCln6nclf cells suggested that impaired zinc homeostasis may be associated with an altered ligand set in CbCln6nclf cells. Importantly, a zinc-complex, ZnII(atsm), restored the nuclear-to-cytoplasmic zinc ratios in CbCln6nclf cells via nuclear zinc delivery, and restored the relationship between subcellular zinc and calcium levels to that observed in healthy control cells. ZnII(atsm) treatment also resulted in a reduction in the number of calcium-rich puncta observed in CbCln6nclf cells. This study highlights the complementarities of bulk and single cell analysis of metal content for understanding disease states. We demonstrate the utility and broad applicability of XFM for subcellular analysis of perturbed biometal metabolism and mechanism of action studies for novel therapeutics to target neurodegeneration.

Acculturation and blood pressure in a community-based sample of Chaldean-American women

With the steady increase of non-European, non-English speaking immigrants to the United States, the relationship between acculturation and risk for cardiovascular disease (CVD) is an issue of growing importance to researchers interested in the health of new immigrant populations. The influence of acculturation processes on adverse changes in blood pressure (BP), a major risk factor for CVD, has been examined in Hispanic-Americans and Asian-Americans. Published studies on this relationship in Arab-Americans are lacking, however, despite their growing numbers. With a specific focus on Chaldean-Americans, a major subgroup of the large Arab-American population located in metropolitan Detroit, Michigan, the current study investigates the influence of level of acculturation on BP in a community probability sample of 130 Chaldean-American women. Study participants were interviewed in their homes (92% response rate). Physical measurements included BP, body mass index (BMI), and waist-hip ratio. Demographic and acculturation data were obtained through a standardized questionnaire. The crude hypertension prevalence in the sample was 16%. Three dimensions of acculturation were identified through content and factor analysis: English language preference, parental school involvement, and ethnic identity. In unadjusted analyses, both English language preference and Chaldean-American ethnic identity were associated (p < 0.01) with lower mean BP, but these differences became nonsignificant when age, BMI, and waist-hip ratio were statistically controlled. Parental school involvement was not associated with BP in any analyses. In this study, the strongest predictors of BP were BMI and waist-hip ratio, both of which were inversely correlated with age, education, English language preference, employment outside the home, and parental school involvement. Future studies of acculturation and BP in Chaldean-Americans (and other Arab-American populations) should use improved measures of acculturation, broader assessments of behavioral and socioeconomic status, and larger samples that includes both genders.

Identification of yeasts isolated from Nigerian sugar cane peels

A pilot study was carried out to determine the yeast species associated with sugar cane peels recovered from three separate dumping sites found in Ojo, a typical market town in Nigeria. Species identities were determined by 26S ribosomal DNA (rDNA) sequencing. By using this method, a total of 6 different yeasts were identified, with Candida tropicalis, a recognised human yeast pathogen, being the species most frequently isolated from these dumping sites. The implications of this and other findings of the study, the apparent first of its kind, are discussed in detail.

Nosocomial transmission of Saccharomyces cerevisiae in bone marrow transplant patients

Saccharomyces cerevisiae is an unusual cause of clinical infection. We describe three bone marrow transplant patients on a haematology unit who developed possible invasive disease with the organism. Two patients died and both these patients appeared to have a related strain of S. cerevisiae. Screening for S. cerevisiae from throat and stool samples revealed four further patients who were carriers. Genotyping of the invasive and carriage strains demonstrated an indistinguishable strain from patients who had been on the unit at the same time, suggesting cross-infection.

Race and glomerulonephritis in patients with and without hepatosplenic Schistosomiasis mansoni

BACKGROUND/AIMS

United States investigators have shown evidence of higher susceptibility to focal segmental glomerulosclerosis (FSGS) in blacks than in whites. This association between race and FSGS has not been assessed outside the US. The present study assesses the association between race and type of glomerulonephritis in a sample of Brazilian patients, taking into account the presence of the hepatosplenic form of Schistosomiasis mansoni (HSM).

METHODS

Eighty patients with focal segmental glomerulosclerosis (FSGS) were compared to 50 with membranoproliferative glomerulonephritis (MPGN). The association between race (i.e. black versus white) and type of glomerulonephritis was adjusted for age, gender and HSM by logistic regression.

RESULTS

Blacks were more likely than whites to have FSGS (as compared to MPGN), both among patients with HSM (odds ratio (OR) = 2.67; 95% confidence interval (CI) = 0.81 - 8.81) and without HSM (OR = 2.19; 95% CI = 0.79 - 6.05). After adjustment for age, gender and HSM, the odds of FSGS remained significantly greater for blacks (OR = 2.49; 95% CI = 1.05 - 5.95).

CONCLUSION

The increased likelihood of FSGS in Brazilian blacks is consistent with findings from US patients. The association between race and type of glomerulonephritis was similar between patients with and without HSM. Future investigations should focus on the mediators factors that might explain these findings.

Candida davenportii sp. nov., a potential soft-drinks spoilage yeast isolated from a wasp

During a survey of yeast ecology in a soft-drinks production facility, a dead wasp was removed from the sampling tap of an external sugar-syrup storage tank. A yeast isolated from the dead wasp was found to be similar, although not identical, in its physiological characteristics to Candida lactis-condensi and Candida stellata. Sequence analysis of the 26S rDNA D1/D2 variable domain revealed that this isolate was most closely related to C stellata, but differed sufficiently in its D1/D2 sequence to indicate that it belonged to a separate species. The yeast species has been named Candida davenportii sp. nov.; the type strain is NCYC 3013T (= CBS 9069T). C davenportii sp. nov. was osmotolerant, moderately preservative-resistant and able to grow in very acidic conditions, i.e. pH 14. This yeast grew well in fruit-containing soft drinks, cola-type beverages and a synthetic soft drink and is therefore a potential cause of spoilage of soft drinks and other sugary food products. Other related yeast species in the same taxonomic clade as C davenportii sp. nov. are also osmotolerant, growing in < 50% (w/v) sugar. Many of these species are associated with insects, specifically bees, bumblebees and leafcutter bees, and many have been reported as the causative agent of spoilage of sugary foods, such as condensed milk, fruit juices and concentrates. It is proposed that C davenportii sp. nov. and other closely related yeasts are primarily associated with Aculeates (bees and wasps). In turn, bees and wasps are attracted by sugary residues in foods such as fruit juices and concentrates, forming the source of infection of these yeasts and thus instigating spoilage.

Identification and distribution of a novel Malassezia species yeast on normal equine skin

This study aimed to investigate the distribution of Malassezia species yeasts on the skin of healthy horses. Acetate tape samples were obtained from the lip, axilla, interbulbar region, groin and anus of 12 healthy horses. The samples were stained and examined microscopically and sites harbouring yeast-like organisms were identified. Contact plates were applied to the skin at these sites and cultured at 26 degrees C and 32 degrees C. No growth was obtained on horse blood, Sabouraud's dextrose or modified Dixon's agar. A pure growth of a Malassezia-type organism was obtained on Sabouraud's dextrose agar enriched with oleic acid when it was incubated at 30 degrees C. It was identified by 26S ribosomal DNA D1/D2 sequence analysis as a member of the genus Malassezia, and most closely related to Malassezia sympodialis. However, the level of sequence divergence indicated that it was a novel species.

Growth response of highly tolerant Eucalyptus species to alkaline pH, bicarbonate and low iron supply

The tolerance of 5 Eucalyptus species (E. gracilis F. Muell., E. halophila D. Carr &amp; S. Carr, E. kondininensis Maiden &amp; Blakely, E. loxophleba Benth. and E. platypus Hook var. heterophylla Blakely) to alkaline conditions, bicarbonate, and low iron availability was assessed in solution culture. All 5 species occur naturally in alkaline or saline soils in semi-arid Western Australia. A treatment solution of pH 9 and containing 10 mmol/L bicarbonate (HCO3–) reduced the rate of height increase and leaf and branch production of most species compared with a control of pH 6 with no bicarbonate. Iron concentration within the youngest fully expanded leaves was reduced for seedlings in the bicarbonate-pH 9 solution. Eucalyptus halophila was an exception, responding positively to the alkaline treatment in having taller seedlings, a greater leaf production, and maintaining a high leaf iron concentration. Eucalyptus gracilis, E. loxophleba and E. platypus had the highest growth rates within the alkaline treatment, but the slow growth and sequestering of iron by E. halophila provided this species with the greatest potential for tolerance. The relative growth and tolerance rankings of the species in solution culture were similar to those obtained in previous field trials on alkaline mine processing wastes. Field selection of species from calcareous or sodic sites, and laboratory screening under high bicarbonate conditions can identify species with the greatest potential for the rehabilitation of alkaline mine wastes and other damaged lands with soils of high pH.

CAM providers' messages to conventional medicine: a qualitative study

Between 30 and 50% of patients use complementary and alternative medicine (CAM). There is little research on the interaction between CAM and conventional providers. We investigated what messages CAM practitioners would convey to conventional medicine (CM). Thirty-four CAM practitioners participated in audiotaped interviews. A coherent message was constructed from the identified themes. CAM practitioners see CAM supporting CM rather than replacing it. Blending of CAM with CM benefits patients and CM providers. CAM reintroduces the concept of healing that technology and time pressures have reduced. The basis of healing is connection, being present in the moment, and seeing patients as whole human beings. Research validating CAM effectiveness will foster integration, as will inclusion of CAM theory and practice in the medical curricula. The messages from CAM practitioners to CM coincide with current views of integrative medicine. Collaboration in research, education, and practice can foster a high-quality health care system.

Race, clinical factors and pre-term birth in a low-income urban setting

While infant mortality rates have declined for both White and African-American populations, the perennial two-fold excess in risk for African Americans remains unchanged, and indeed, may have increased since 1985. One potential explanation for the excess risk in African Americans might be racial differences in maternal clinical risk factors, such as prior pregnancy history and pregnancy complications. This paper examines the contributions of such clinical indicators to racial differences in pre-term delivery in a study sample of urban, low-income women, aged 18 to 43 years.

METHODS

Study participants were enrolled during their first prenatal care visit at one of four hospital-based, prenatal care clinics in Baltimore City. Medical history and pregnancy outcome data were abstracted from clinical records. Multiple logistic regression models were used to assess the independent relationship between race and pre-term birth, after controlling for clinical factors.

RESULTS

Without adjustment for clinical risk factors, African-American women were 1.8 times more likely than White women to have a pre-term birth outcome (95% confidence interval 1.20-2.78). After statistical adjustment for the clinical variables, however, the association between race and pre-term birth was diminished (OR = 1.64, 95% confidence interval: 0.99-2.72). Moreover, the associations between certain clinical risks and pre-term birth were stronger for African-American than White women.

CONCLUSION

These results suggest that attention to clinical risk factors among African-American women may be an important avenue for reducing Black/White racial disparities in pre-term birth.

Phylogenetic analysis of the psychrophobic yeast Arxiozyma telluris and the reinstatement of Candida pintolopesii (van Uden) Meyer et Yarrow and Candida slooffii van Uden et do Carmo Sousa

A phylogenetic analysis was conducted upon ten strains of the psychrophobic yeast species Arxiozyma telluris using nuclear rDNA (18S and 26S) and mitochondrial cytochrome-c oxidase subunit II (COX2) gene sequences. Strains examined included those described originally as Candida slooffii, Torulopsis bovina (= Candida bovina) and Torulopsis pintolopesii (= Candida pintolopesii), which are all currently accepted as synonyms of Arxiozyma telluris. Comparative 18S rDNA sequence analysis showed that these strains formed a genealogically highly related group, which was phylogenetically distinct from any other ascomycetous species studied. The results showed that A. telluris, as currently described, appears to be composed of a complex of closely related but nevertheless separate taxa. rDNA and COX2 gene sequence data revealed that CBS 1787T, the type strain of C. pintolopesii, the currently recognized asexual form (anamorph) of A. telluris, along with strains CBS 2676 and CBS 2985 formed a distinct taxon that is phylogenetically separate from A. telluris. Similarly, the sequence data also showed that C. slooffii is a distinct taxon and support the reinstatement of this species. However, with regard to the relationship between the type strains of A. telluris (CBS 2685T) and C bovina (CBS 2760T), discrepancies were observed between the rDNA and COX2 sequence datasets, and these results are discussed in more detail.

Disentangling measures of individual perceptions of community social dynamics: results of a community survey

This study examined how different measures of individual perceptions of community social dynamics relate to each other and how these measures relate to self-reported general health and depressive symptoms. Results of a principal components analysis conducted to investigate the interrelationships between these individual measures suggest that these measures measure separate phenomena. In addition, in results of multiple-regression analyses conducted to examine associations between the various measures of individual perceptions of community social dynamics and the dependent variables of self-reported general health and depressive symptoms, sense of community, perceived neighborhood control, and neighborhood participation were all associated with the outcome variables in separate regression models. In a regression model with these three variables added to control variables, only sense of community was significantly, albeit modestly, associated with depressive symptoms and self-reported general health.

Candida sorbosivorans sp. nov., a new member of the genus Candida Berkhout

A yeast, strain NCYC 2938T, was isolated from contaminated industrial material. This material was involved in a cascade continuous process for oxidizing sorbitol (D-glucitol) to L-sorbose. The isolate is similar, although not identical, to Candida geochares and Candida magnoliae in its physiological characteristics. Sequence analysis of the 26S rDNA D1/D2 variable domain showed that it was similar to those of both Candida species, but differed sufficiently to be considered as a separate species. Both the physiological characteristics and the unique 26S rDNA D1/D2 sequence of NCYC 2938T are described here, and the yeast has been named Candida sorbosivorans sp. nov. The type strain is NCYC 2938T (= CBS 8768T).

Adverse events associated with hepatitis B vaccine in U.S. children less than six years of age, 1993 and 1994

PURPOSE

This study evaluated infrequent adverse reactions to hepatitis B vaccine by investigating the association of this vaccine with adverse health outcomes for U.S. children less than six years of age. The evaluation of the association between hepatitis B vaccine and chronic arthritis provides needed data, relevant to the Institute of Medicine's Report that there are inadequate data available to assess the causal relationship of hepatitis B vaccine to arthritis risk.

METHODS

The 1993 (n = 5505 children) and 1994 (n = 6515 children) National Health Interview Survey (NHIS) datasets were analyzed to provide post-marketing surveillance data from probability samples of the U.S. population. Incident cases of adverse events were determined from the temporal association between the hepatitis B vaccination and the adverse events. Logistic regression modeling was used to adjust for potential confounding.

RESULTS

Controlling for age, race, and gender simultaneously in the 1994 NHIS, hepatitis B vaccine was found to be associated with prevalent arthritis [odds ratio (OR) = 5.91, 95% confidence interval (CI) = 1.05-33.14], incident acute ear infections (OR = 1.60, 95% CI = 1.00-2.58), and incident pharyngitis/nasopharyngitis (OR = 1.41, 95% CI = 0.95-2.09).

CONCLUSIONS

Evidence from this study suggests that hepatitis B vaccine is positively associated with adverse health outcomes in the general population of US children.

Unintended pregnancy and preterm birth

About one-third of all pregnancies that result in live births in the US are unintended. Despite the large number of these births, little is known about the outcomes of unintended pregnancies. The purpose of the current study was to evaluate the association between intendedness of pregnancy and preterm birth in a large prospective cohort of women who reported for prenatal care. Pregnant, black, low-income women were enrolled into this study at four hospital-based prenatal care clinics and one off-site hospital-affiliated prenatal clinic in Baltimore City. A self-administered questionnaire to assess demographic and psychosocial data was completed by each woman in the cohort at the time of enrolment in the study. The questionnaire contained an item to measure intendedness of the pregnancy. A total of 922 women comprised the final sample for analysis. For the analyses, intendedness was dichotomised as: intended (wanted now or sooner) vs. unintended (mistimed, unwanted or unsure). Overall, 13.7% of all births to women in the sample were preterm. In a logistic regression model, after controlling for potential confounding by clinical and behavioural predictors of preterm delivery, unintended pregnancy was significantly associated with preterm delivery (adjusted RR = 1.82, 95% confidence interval [1.08,3.08], P = 0.026). In this study of a cohort of urban, clinic-attending, low-income, pregnant black women, unintended pregnancy had a statistically significant association with preterm birth. After adjustment for behavioural and clinical risks, women with unintended pregnancies had almost twice the risk of a preterm delivery as women with intended pregnancies.

Sorbic acid resistance: the inoculum effect

Zygosaccharomyces is a genus associated with the more extreme spoilage yeasts. Zygosaccharomyces spoilage yeasts are osmotolerant, fructophiles (preferring fructose), highly-fermentative and extremely preservative-resistant. Zygosaccharomyces bailii can grow in the presence of commonly-used food preservatives, benzoic, acetic or sorbic acids, at concentrations far higher than are legally permitted or organolepically acceptable in foods. An inoculum effect has been described for many micro-organisms and antimicrobial agents. The minimum inhibitory concentration (MIC) increases with the size of the inoculum; large inocula at high cell density therefore require considerably higher concentrations of inhibitors to prevent growth than do dilute cell suspensions. A substantial inoculum effect was found using sorbic acid against the spoilage yeast Zygosaccharomyces bailii NCYC 1766. The inoculum effect was not caused by yeasts metabolizing or adsorbing sorbic acid, thereby lowering the effective concentration; was not due to absence of cell-cell signals in dilute cell suspensions; and was not an artefact, generated by insufficient time for small inocula to grow. The inoculum effect appeared to be caused by diversity in the populations of yeast cells, with higher probability of sorbic acid-resistant cells being present in large inocula. It was found that individual cells of Zygosaccharomyces bailii populations, grown as single cells in microtitre plate wells, were very diverse, varying enormously in resistance to sorbic acid. 26S ribosomal DNA sequencing did not detect differences between the small fraction of resistant 'super cells' and the average population. Re-inoculation of the 'super cells' after overnight growth on YEPD showed a normal distribution of resistance to sorbic acid, similar to that of the original population. The resistance phenotype was therefore not heritable and not caused by a genetically distinct subpopulation. It was concluded that resistance of the spoilage yeast Zygosaccharomyces bailii to sorbic acid was due to the presence of small numbers of phenotypically resistant cells in the population.

Influence of light availability on leaf structure and growth of two Eucalyptus globulus ssp. globulus provenances

Light availability strongly affects leaf structure of the distinctive ontogenetic leaf forms of Eucalyptus globulus Labill. ssp. globulus. Late-maturing plants from St. Marys, Tasmania and early maturing plants from Wilsons Promontory, Victoria (hereafter referred to as Wilsons Prom.) were grown for 9 months in 100, 50 or 10% sunlight. Growth, biomass and leaf area were significantly reduced when plants were grown in 10% sunlight. Provenance differences were minimal despite retention of the juvenile leaf form by the Tasmanian plants throughout the study. The time taken for initiation of vegetative phase change by the Wilsons Prom. saplings increased with decreasing light availability, but the nodal position of change on the main stem remained the same. Both juvenile and adult leaves remained horizontal in low light conditions, but became vertical with high irradiance. Leaf dimensions changed with ontogenetic development, but were unaffected by light availability. Juvenile leaves retained a dorsiventral anatomy and adult Wilsons Prom. leaves retained an isobilateral structure despite a tenfold difference in light availability. Stomatal density and distribution showed ontogenetic and treatment differences. At all irradiances, juvenile leaves produced the smallest stomata and adult leaves the largest stomata. Amphistomy decreased with decreasing irradiance. Detrended, correspondence analysis ordination highlighted the structural changes influenced by ontogenetic development and light availability. Adult leaves had characteristics similar to the xeromorphic, sun-leaf type found in arid, high-light conditions. Although juvenile leaves had characteristics typical of mesomorphic leaves, several structural features suggest that these leaves are more sun-adapted than adult leaves.

Three new species in the Saccharomyces sensu stricto complex: Saccharomyces cariocanus, Saccharomyces kudriavzevii and Saccharomyces mikatae

On the basis of genetic analysis, molecular karyotyping and sequence analyses of the 18S rRNA and internal transcribed spacer (ITS) region, three new Saccharomyces species are described, Saccharomyces cariocanus (with type strain NCYC 2890T), Saccharomyces kudriavzevii (with type strain NCYC 2889T) and Saccharomyces mikatae (with type strain NCYC 2888T). Genetic and molecular analyses did not confirm the previously observed conspecificity of Saccharomyces paradoxus and S. cariocanus. The latter species exhibits postzygotic isolation from representative strains from all known geographical populations of S. paradoxus: European, Far-East Asian, North American and Hawaiian.

Unfair treatment, neighborhood effects, and mental health in the Detroit metropolitan area

Why do racial differences in many indicators of mental and emotional well-being show inconsistent patterns? We propose that mental and emotional well-being are influenced by aspects of the social context, including experiences of unfair treatment and the concentration of households with incomes below the poverty level, and that differential exposure to these factors influences racial differences in mental well-being. We analyze the reporting of psychological distress and life satisfaction in a multistage area probability sample of 1,139 African American and white residents of the Detroit metropolitan area aged 18 and older. Both psychological distress and life satisfaction are significantly associated with exposure to unfair treatment and with the proportion of households in the census block group that were below the poverty level. Racial differences in psychological distress and life satisfaction were eliminated or reversed once differentials in the percent of households living below the poverty line and exposure to unfair treatment were accounted for. These findings contribute to a growing body of evidence that "race" effects operate through multiple pathways that include race-based residential segregation and its attendant economic disinvestment at the community level, and interpersonal experiences of unfair treatment.

Chromosomal evolution in Saccharomyces

The chromosomal speciation model invokes chromosomal rearrangements as the primary cause of reproductive isolation. In a heterozygous carrier, chromosomes bearing reciprocal translocations mis-segregate at meiosis, resulting in reduced fertility or complete sterility. Thus, chromosomal rearrangements act as a post-zygotic isolating mechanism. Reproductive isolation in yeast is due to post-zygotic barriers, as many species mate successfully but the hybrids are sterile. Reciprocal translocations are thought to be the main form of large-scale rearrangement since the hypothesized duplication of the whole yeast genome 10(8) years ago. To test the chromosomal speciation model in yeast, we have characterized chromosomal translocations among the genomes of six closely related species in the Saccharomyces 'sensu stricto' complex. Here we show that rearrangements have occurred between closely related species, whereas more distant ones have colinear genomes. Thus, chromosomal rearrangements are not a prerequisite for speciation in yeast and the rate of formation of translocations is not constant. These rearrangements appear to result from ectopic recombination between Ty elements or other repeated sequences.

Primordial prevention of cardiovascular disease among African-Americans: a social epidemiological perspective

BACKGROUND

The primordial prevention of cardiovascular disease (CVD) among African-Americans represents a formidable challenge for public health. This paper discusses the nature of this challenge, highlighting the role that economic and cultural factors play in shaping the distributions of major CVD risk factors among African-Americans. The paper concludes with specific suggestions for research.

METHODS

Data from recent national health surveys on black/white differences in major CVD risk factors like hypertension, obesity, cholesterol, cigarette smoking, and physical inactivity were reviewed for the purpose of identifying promising avenues for primordial prevention research among African-Americans.

RESULTS

Cigarette smoking has a delayed onset among African-Americans compared to whites. Black/white differences in "vigorous" leisure-time physical activity (e.g., social dancing and team sports) are not apparent until around age 40. These findings have relevance for primordial prevention work in black communities since they suggest the existence of broad-based, health-relevant cultural norms which could support primordial prevention programs, such as regular physical activity, across the life cycle.

CONCLUSIONS

CVD primordial prevention programs among African-Americans must be grounded in an understanding of how cultural values as well as economic conditions shape CVD risk factor distributions in this population. Ultimate success will depend on the strength of the partnerships that public health researchers, primary care providers, and community residents are able to build.

Zygosaccharomyces lentus: a significant new osmophilic, preservative-resistant spoilage yeast, capable of growth at low temperature

Zygosaccharomyces lentus is a yeast species recently identified from its physiology and 18S ribosomal sequencing (Steels et al. 1999).The physiological characteristics of five strains of this new yeast so far isolated were investigated, particularly those of technical significance for a spoilage yeast, namely temperature range, pH range, osmotolerance, sugar fermentation, resistance to food preservatives such as sorbic acid, benzoic acid and dimethyldicarbonate (DMDC; Velcorin). Adaptation to benzoic acid, and growth in shaking and static culture were also investigated. Zygosaccharomyces lentus strains grew over a wide range of temperature (4-25 degrees C) and pH 2.2-7.0. Growth at 4 degrees C was significant. Zygosaccharomyces lentus strains grew at 25-26 degrees C in static culture but were unable to grow in aerobic culture close to their temperature maximum. All Z. lentus strains grew in 60% w/v sugar and consequently, are osmotolerant. Zygosaccharomyces lentus strains could utilize sucrose, glucose or fructose as a source of fermentable sugar, but not galactose. Zygosaccharomyces lentus strains were resistant to food preservatives, growing in sorbic acid up to 400 mg l-1 and benzoic acid to 900 mg l-1 at pH 4.0. Adaptation to higher preservative concentrations was demonstrated with benzoic acid. Resistance to DMDC was shown to be greater than that of Z. bailii and Saccharomyces cerevisiae. This study confirms that Z. lentus is an important food spoilage organism potentially capable of growth in a wide range of food products, particularly low pH, high sugar foods and drinks. It is likely to be more significant than Z. bailii in the spoilage of chilled products.

Malaria infection during pregnancy: intrauterine growth retardation and preterm delivery in Malawi

In sub-Saharan Africa, malaria infection in pregnancy contributes to low birth weight through intrauterine growth retardation (IUGR) and preterm delivery (PTD). It was hypothesized that malaria-associated PTD and IUGR have differing etiologies due to timing of infection. In a prospective cohort of primigravid women enrolled at the antenatal clinic of Mangochi District Hospital in Malawi, the associations were investigated between antenatal or delivery parasitemias and IUGR or PTD. Among 178 singleton deliveries, 35% of infants were preterm or had IUGR. Cord blood parasitemia (odds ratio [OR]=3.34; 95% confidence interval [CI], 1.3-8.8], placental parasitemia (OR=2.43; 95% CI, 1.2-5.1), and postdelivery maternal peripheral parasitemia (OR=2.78; 95% CI, 1.3-6.1) were associated with PTD. Parasitemia and/or clinically diagnosed malaria in the antenatal period was associated with IUGR (OR=5.13; 95% CI, 1.4-19.4). Delivery parasitemias had borderline associations with IUGR. The risk patterns observed suggest that the timing and severity of infection influences the occurrence of IUGR or PTD.

Ontogenetic differences in mesophyll structure and chlorophyll distribution in Eucalyptus globulus ssp. globulus

Mesophyll structure has been associated with the photosynthetic performance of leaves via the regulation of internal light and CO(2) profiles. Differences in mesophyll structure and chlorophyll distribution within three ontogenetically different leaf types of Eucalyptus globulus ssp. globulus were investigated. Juvenile leaves are blue-grey in color, dorsiventral (adaxial palisade layer only), hypostomatous, and approximately horizontal in orientation. In contrast, adult leaves are dark green in color, isobilateral (adaxial and abaxial palisade), amphistomatous, and nearly vertical in orientation. The transitional leaf type has structural features that appear intermediate between the juvenile and adult leaves. The ratio of mesophyll cell surface area per unit leaf surface area (A(mes)/A) of juvenile leaves was maximum at the base of a single, adaxial palisade layer and declined through the spongy mesophyll. Chlorophyll a + b content showed a coincident pattern, while the chlorophyll a:b ratio declined linearly from the adaxial to abaxial epidermis. In comparison, the mesophyll of adult leaves had a bimodal distribution of A(mes)/A, with maxima occurring beneath both the adaxial and abaxial surfaces within the first layer of multiple palisade layers. The distribution of chlorophyll a + b content had a similar pattern, although the maximum ratio of chlorophyll a:b occurred immediately beneath the adaxial and abaxial epidermis. The matching distributions of A(mes)/A and chlorophyll provide further evidence that mesophyll structure may act to influence photosynthetic performance. These changes in internal leaf structure at different life stages of E. globulus may be an adaptation for increased xeromorphy under increasing light exposure experienced from the seedling to adult tree, similar to the characteristics reported for different species according to sunlight exposure and water availability within their native habitats.

Zygosaccharomyces lentus sp. nov., a new member of the yeast genus Zygosaccharomyces Barker

Unusual growth characteristics of a spoilage yeast, originally isolated from spoiled whole-orange drink and previously identified as Zygosaccharomyces bailii, prompted careful re-examination of its taxonomic position. Small-subunit rRNA gene sequences were determined for this strain and for four other strains also originally described as Z. bailii but which, in contrast to other strains of this species, grew poorly or not at all under aerobic conditions with agitation, failed to grow in the presence of 1% acetic acid and failed to grow at 30 degrees C. Comparative sequence analysis revealed that these strains represented a phylogenetically distinct taxon closely related to, but distinct from, Z. bailii and Zygosaccharomyces bisporus. Furthermore, sequence analysis of the internal transcribed spacer (ITS) region showed that, while all five strains had identical ITS2 sequences, they could be subdivided into two groups based on ITS1 sequences. Despite such minor inter-strain sequence variation, these yeasts could readily be distinguished from all other currently described Zygosaccharomyces species by using ITS sequences. On the basis of the phylogenetic results presented, a new species comprising the five strains, Zygosaccharomyces lentus sp. nov., is described and supporting physiological data are discussed, including a demonstration that growth of this species is particularly sensitive to the presence of oxygen. The type strain of Z. lentus is NCYC D2627T.

The contribution of baseline weight and weight gain to blood pressure change in African Americans: the Pitt County Study

PURPOSE

The positive association between obesity and blood pressure has been less consistent in African Americans than whites. This is especially true for African American men. This study investigated the sex-specific associations between baseline body mass index (BMI), weight change (kilograms), and five-year hypertension incidence and changes in blood pressure in a cohort of African Americans ages 25-50 years at baseline.

METHODS

The Pitt County Study is a longitudinal investigation of anthropometric, psychosocial, and behavioral predictors of hypertension in African Americans. Data were obtained through household interviews and physical examinations in 1988 and 1993.

RESULTS

Baseline BMI was positively and independently associated with changes in blood pressure after controlling for weight change and other covariates. When participants were stratified by sex-specific overweight vs. nonoverweight status at baseline, weight gain was significantly associated with increases in blood pressure only among the initially nonoverweight.

CONCLUSIONS

Baseline weight for all respondents, and weight gain among the nonoverweight at baseline, were independent predictors of blood pressure increases in this cohort of African Americans.

Physical activity and NIDDM in African-Americans. The Pitt County Study

OBJECTIVE

Studies directly examining the association between physical activity and NIDDM in African-Americans are rare. Consequently, the strength of this association in this ethnic minority group remains unclear. The current study broadly characterizes the types of physical activity engaged in by a community sample of working-class African-Americans and then quantifies the association between physical activity and NIDDM risk in this population.

RESEARCH DESIGN AND METHODS

During the 1993 reexamination of participants in the Pitt County Study in North Carolina, data on NIDDM history, current use of insulin or oral hypoglycemic drugs, and approximately 12-h overnight fasting blood glucose (FBG) were obtained from 598 women and 318 men, ages 30-55 years. The presence of NIDDM was determined by current insulin or medication use and FBG > or = 140 mg/dl. Study participants were assigned to one of four categories of physical activity: strenuous, moderate, low, or inactive.

RESULTS

The weighted prevalence of NIDDM in the sample was 7.1%. After adjustment was made for age, sex, education, BMI, and waist-to-hip ratio, NIDDM risk for moderately active subjects was one-third that for the physically inactive subjects (odds ratio [OR], 0.35; 95% CI, 0.12-0.98). The ORs for low (OR, 0.51; 95% CI, 0.20-1.29) and strenuous (OR, 0.65; 95% CI, 0.26-1.63) activity also tended to be lower. A summary OR that contrasted any activity versus no activity was 0.51 (95% CI, 0.23-1.13).

CONCLUSIONS

Moderate physical activity was strongly associated with reduced risk for NIDDM in this sample. While replication of these findings is needed, public health interventions designed to increase moderate (leisure-time) physical activity in black adults should be strongly encouraged.

Phylogenetic heterogeneity of the genus Williopsis as revealed by 18S rRNA gene sequences

A phylogenetic investigation of the ascomycetous yeast genus Williopsis was performed by using 18S rRNA gene sequence analysis. Comparative sequence analysis revealed the genus to be phylogenetically heterogeneous. The five varieties of Williopsis saturnus [var. mrakii, var. sargentensis, var. saturnus (type), var. suaveolens and var. subsufficiens] were found to have identical 18S rRNA gene sequences and formed a distinct group, quite separate from all other Williopsis and non-Williopsis species examined. Williopsis mucosa was found to be the closet phylogenetic relative to the Williopsis saturnus group, however a sequence divergence of approximately 2.3% suggests this species may belong to a separate genus. The recently described species Williopsis salicorniae was found to exhibit a relatively close association with Ogataea minuta (identical to Pichia minuta), the type species of the genus Ogataea. The remaining two members of the genus, Williopsis californica and Williopsis pratensis, were found to form distinct lineages, displaying no specific association with any other Williopsis or non-Williopsis species. Based on comparative analysis of 18S rRNA genes it is apparent that the genus Williopsis as presently constituted is not monophyletic, and that the five currently recognized species form separate sublines each potentially worthy of separate generic status. The genus Williopsis should be restricted to the type species Williopsis saturnus and its five varieties. Despite the five varieties of Williopsis saturnus being genealogically indistinguishable at the 18S rRNA gene level, sequence analysis of the Internal transcribed spacer (ITS) region revealed that the five varieties could be differentiated on both their ITS1 and their ITS2 sequences, providing further evidence of the value of ITS sequences for discrimination of yeasts at the subspecies level.

Alcohol consumption and changes in blood pressure among African Americans. The Pitt County Study

The Pitt County Study is a longitudinal investigation of anthropometric, psychosocial, and behavioral predictors of hypertension in African Americans who were aged 25-50 years at baseline in 1988. At baseline, a strong dose-response gradient was observed for alcohol consumption and blood pressure for both sexes. The current study investigated whether baseline alcohol consumption or, alternatively, changes in drinking status predicted 5-year changes in blood pressure among the 652 women and 318 men who satisfied all inclusion criteria for the longitudinal analyses. In multivariate regression analyses, baseline alcohol consumption was not significantly associated with changes in blood pressure or hypertension incidence (systolic/diastolic blood pressure > or = 160/95 mmHg) by 1993. Change in drinking status, however, was significantly associated with changes in systolic pressure. The systolic pressure increase among individuals who initiated alcohol consumption was 6.2 mmHg (95% confidence interval (CI) 1.1-6.4) greater than abstainers, while that for individuals who reported drinking at both time points was 3.8 mmHg (95% CI 1.3-11.1) greater. Blood pressure increases for persons who discontinued drinking were comparable to those of abstainers. Results were independent of baseline age, body mass index, blood pressure, and sex. Social and economic disadvantage in 1988 was significantly associated with continuation and initiation of alcohol consumption by 1993.

Social support, stress, and blood pressure in black adults

Psychosocial factors arising from socioeconomic disadvantage and discrimination may contribute to the excess risk of elevated blood pressure in African-Americans. The purpose of this study was to assess the association of social support and stress with blood pressure in a community-based sample of 25-to 50-year-old black adults in Pitt County, NC. A stratified random sample of dwellings was selected in 1988, and 1,784 black adults (80% of those eligible) were interviewed. Analyses were sex specific and adjusted for age, obesity, and waist/hip ratio. In separate analyses of emotional support, instrumental support, and stress with blood pressure, all associations were in the predicted direction (inverse for support, direct for stress) but were stronger for systolic than for diastolic blood pressure. Differences in systolic blood pressure associated with low support or high stress ranged from 5.2 to 3.6 mmHg in women and 3.5 to 2.5 mmHg in men. In simultaneous regression analyses of support and stress, each of the separate effects was reduced for women, but a sizable aggregate effect of low support and high stress remained [+7.2 mmHg (95% confidence limits = +1.3, +13.1) for systolic blood pressure and +4.0 mmHg (95% confidence limits = +0.1, +7.9) for diastolic blood pressure.

Job strain and blood pressure in African Americans: the Pitt County Study

OBJECTIVES

This report examined whether job strain (or its components, decision latitude and job demands) was associated with elevated blood pressure levels in a community-based sample of 726 African-American adults.

METHODS

Blood-pressure, anthropometric, behavioral, demographic, and psychosocial data were collected for the current cross-sectional analyses during home interviews conducted for the second wave (1993) of the Pitt County Study (North Carolina), a prospective cohort study of hypertension among African Americans.

RESULTS

Job strain was not associated with blood pressure among men or women in this study. However, men in the 80th percentile of decision latitude had more than a 50% decrease in the prevalence of hypertension compared with men in the 20th percentile (odds ratio = .46, 95% confidence interval = .22, .96).

CONCLUSIONS

These results indicate that decision latitude may be important for hypertension risk among African-American men. More research is needed on African Americans to determine why job strain and its two component variables differ in their associations with blood pressure for men and women.

A phylogenetic analysis of the genus Saccharomyces based on 18S rRNA gene sequences: description of Saccharomyces kunashirensis sp. nov. and Saccharomyces martiniae sp. nov

A phylogenetic investigation of the ascomycetous yeast genus Saccharomyces was performed by using 18S rRNA gene sequence analysis. Comparative sequence analysis showed that the genus is phylogenetically very heterogeneous. Saccharomyces species were found to be phylogenetically interdispersed with members of other ascomycetous genera (e.g., the genera Kluyveromyces, Torulaspora, and Zygosaccharomyces). The four species of the Saccharomyces sensu stricto complex (viz., Saccharomyces bayanus, Saccharomyces cerevisiae, Saccharomyces paradoxus, and Saccharomyces pastorianus) were found to be phylogenetically closely related to one another, displaying exceptionally high levels of sequence similarity (> or = 99.9%). These four species formed a natural group that was quite separate from the other Saccharomyces and non-Saccharomyces species examined. Saccharomyces exiguus and its anamorph, Candida holmii, were found to be genealogically almost identical and, along with Saccharomyces barnettii, formed a stable group closely related to, but nevertheless distinct from, Kluyveromyces africanus, Kluyveromyces lodderae, Saccharomyces rosinii, Saccharomyces spencerorum, and Saccharomyces sp. strain CBS 7662T (T = type strain). Saccharomyces spencerorum and Kluyveromyces lodderae displayed a particularly close genealogical affinity with each other, as did Saccharomyces castellii and Saccharomyces dairensis. Similarly, Saccharomyces servazzii, Saccharomyces unisporus, and Saccharomyces sp. strain CBS 6904 were found to be genotypically highly related and to form a phylogenetically distinct lineage. The recently reinstated species Saccharomyces transvaalensis was found to form a distinct lineage and displayed no specific association with any other Saccharomyces or non-Saccharomyces species. Saccharomyces kluyveri formed a very loose association with a group which included Kluyveromyces thermotolerans, Kluyveromyces waltii, Zygosaccharomyces cidri, and Zygosaccharomyces fermentati. Saccharomyces spp. strain CBS 6334T, on the other hand, displayed no specific association with any of the other Saccharomyces spp. studied, although a neighbor-joining analysis did reveal that this strain exhibited a loose phylogenetic affinity with Kluyveromyces polysporus and Kluyveromyces yarrowii. On the basis of the phylogenetic findings, two new Saccharomyces species, Saccharomyces kunashirensis (with type strain CBS 7662) and Saccharomyces martiniae (with type strain CBS 6334), are described.

Psychosocial stressors and low birthweight in an urban population

INTRODUCTION

Low birthweight is a major determinant of infant mortality, as well as a contributor to infant and childhood morbidity. A key issue is how to reduce the incidence of low birthweight in the United States. One emerging factor is exposure to psychosocial stressors. In this research, we evaluated the association between exposure to psychosocial stressors and low birthweight in a population of urban, low-income pregnant women.

METHODS

Over 2,000 pregnant women 18 years of age and older were enrolled in this prospective study and recruited at their first prenatal care visit. We obtained information on maternal exposure to stressors. After the pregnancy, we abstracted clinical records of each woman enrolled in the study. Logistic regression was used to estimate the adjusted odds ratio for the association between stressor group membership and low birthweight, controlling for the effects of confounding factors.

RESULTS

In logistic regression analyses stratified by race, for African-American women, the following variables were significantly associated with low birthweight: smoking, hypertension, low prepregnancy weight, hospitalization during pregnancy, previous preterm birth, and exposure to stressors. For Caucasian women, significant predictors were: smoking, drug use, hospitalization during pregnancy, hypertension, and previous preterm birth. Exposure to stressors was also significantly associated with many clinical and behavioral risks for low birthweight.

CONCLUSION

Our results suggest two potential mechanisms for an association between stressors and low birthweight. Exposure to stressors may be indirectly associated with low birthweight through a relationship with clinical and behavioral risks for low birthweight. Exposure to psychosocial stressors may also be directly associated with risk of low birthweight among African-American women.

Determinants of hypertension in West Africa: contribution of anthropometric and dietary factors to urban-rural and socioeconomic gradients

The determinants of hypertension in West Africa have not been well defined. The authors sampled 598 participants aged 45 years or more from a recent population-based survey in southwest Nigeria (190 rural men and women, 205 urban poor men and women, and 203 retired railway workmen). The estimated mean age was 61 (10) years. Mean pressures were low relative to westernized societies: systolic blood pressure = 124 (24) mmHg, diastolic blood pressure = 72 (13) mmHg. Both men and women were remarkably lean: body mass index = 21.3 (3.6) and 23.0 (5.2) kg/m2, respectively. Hypertension prevalence increased across the gradient from rural farmers to urban poor to railway workers: 14, 25, and 29 percent, respectively, had a blood pressure of 140/90 mmHg or greater, and 3, 11, and 14 percent, respectively, had a blood pressure of 160/95 mmHg or greater (p for trend < 0.01 for both cutpoints). On the basis of a 24-hour urine sample, daily electrolyte excretion was 110 (57) mEq of sodium and 46 (24) mEq of potassium. Mean sodium:potassium ratio was 2.6 (1.0) and was higher among the urban residents (p < 0.01) and correlated with systolic and diastolic pressures (r = 0.16-0.18, p < 0.01). These findings provide quantitative estimates of the impact of known hypertension risk factors in West Africa and demonstrate the basis for increased prevalence with urbanization and associated economic and dietary change. These results also provide support for recommendations for prevention in West Africa and provide a benchmark against which to compare populations in the African diaspora.

Use of an rRNA internal transcribed spacer region to distinguish phylogenetically closely related species of the genera Zygosaccharomyces and Torulaspora

Analyses of the sequences of the small-subunit (18S) rRNA gene and two internal transcribed spacers (ITSs), ITS1 and ITS2, revealed that members of the yeast genera Torulaspora and Zygosaccharomyces are phylogenetically intermixed. Despite some minor differences in 18S rRNA-, ITS1-, and ITS2-derived trees, in general the patterns of the relationships inferred from the three chronometers were in good agreement. The ITS sequences of Torulaspora and Zygosaccharomyces species exhibited far greater interspecies differences than the 18S rRNA sequences and were better than 18S rRNA sequences for measuring close genealogical relationships. Despite the existence of interstrain ITS sequence variation in some species, it is possible to identify conserved regions in both ITSs that are useful in species differentiation.

A genetically engineered V79 cell line SD1 expressing rat CYP2B1 exhibits chromosomal instability at the integration site of the transfected DNA

The genetically engineered cell line SD1 was constructed by co-transfection of V79 Chinese hamster cells with two plasmids: one containing a full-length cDNA encoding rat CYP2B1 and the second incorporating a selective marker gene. This cell line has been used in gene mutation tests and in cytokinesis-block micronucleus assays to identify procarcinogens which are metabolized by CYP2B1 to reactive metabolites. An elevated frequency of spontaneous micronuclei was recorded in SD1 cells compared to parental V79 cultures. Karyotypic analysis revealed a chromosomal instability which was manifested by amplification of the p-arms of a chromosome designated 'n' (derived from chromosome 8). This chromosome was variable in length and sometimes exhibited a telomeric fusion which led to the formation of a dicentric chromosome. Fluorescence in situ hybridization with digoxigenin-labelled plasmid DNA showed the presence of pSV450 plasmid DNA coamplified with genomic DNA sequences located in the terminal region of chromosome 'n'.

Depression in black and white women. The role of marriage and socioeconomic status

The degree to which the relationship between race and depression in US black and white women is modified by socioeconomic and marital status was investigated. Data on 534 black and 836 white women, 25 to 64 years old, obtained from the 1986 Americans' Changing Lives national survey were utilized. Depression was measured by the Centers for Epidemiologic Studies Depression scale. Poverty status and education were used as indicators of socioeconomic status (SES). For both black and white women, the prevalence of depression was higher among those with lower as compared to higher SES, and among the unmarried as compared to the married. The unstratified, age-adjusted odds of depression for black women was twice that for white women (odds ratio (OR) = 2.2; 95% confidence interval (CI), 1.7 to 2.8); however, when stratified by poverty status, race effects were observed for nonpoor (OR = 2.2; 95% CI, 1.6 to 3.0) but not for poor women (OR = 1.3; 95% CI, 0.7 to 2.1). Race effects were also more pronounced among married (OR = 2.0; 95% CI, 1.4 to 2.9) than unmarried women (OR = 1.6; 95% CI, 1.1 to 2.4). Controlling for known confounders did not alter these results. Additional analyses revealed that the black excess risk for depression was concentrated among higher SES, married women, with marital difficulties appearing to pay a major role in their elevated depression scores.

The genetic relationship of Lodderomyces elongisporus to other ascomycete yeast species as revealed by small-subunit rRNA gene sequences

The 18S rRNA gene sequence of the ascomycete yeast Lodderomyces elongisporus was determined by PCR-direct sequencing. The phylogenetic inter-relationship of Lodderomyces elongisporus and other ascomycete yeast species was examined by comparative sequence analysis. Lodderomyces elongisporus was found to be most closely related to Candida parapsilosis, C. tropicalis and C. albicans, exhibiting sequence similarity values of greater than 97.5%. The relationship between L. elongisporus and Candida parapsilosis in particular is discussed with regard to the possibility that L. elongisporus is the teleomorph (sexual form) of C. parapsilosis.

The joint effects of race and age on the risk of end-stage renal disease attributed to hypertension

To describe the joint effects of race and age on the risk of end-stage renal disease (ESRD) attributed to hypertension (ESRD-HT), we analyzed data for white and black adults, 20 to 84 years of age, reported by the United States Renal Data System during the period 1987 to 1990. The risk of ESRD-HT increased substantially with age for both blacks and whites; however, at each age, the risk was greater for blacks. A more in-depth description of the combination of effects involving race and age on ESRD-HT incidence was provided by two models of joint effects, one additive and the other multiplicative. Both models used the 20- to 24-year age group as the referent. Under the additive model the risk of ESRD-HT in blacks attributable to the joint effects between race and age increased continuously from younger to older groups. This indicates that although ESRD-HT risk increases with age for both blacks and whites, the increase for blacks is greater than expected if the effects of race were independent of the effects of age. However, the multiplicative model indicated that the proportional increase with age in ESRD-HT risk among blacks, as compared with whites, was more striking for younger ages (< or = 50 years among women and < or = 40 years among men), and especially so for men. This suggests a more accelerated course of hypertension toward ESRD for blacks (especially younger men) than for whites. A conceptual model to explain these patterns of race-age joint effects is proposed.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic interrelationship among species of the genus Zygosaccharomyces as revealed by small-subunit rRNA gene sequences

The phylogenetic interrelationship of species of the genus Zygosaccharomyces was examined by 18S rRNA gene sequencing. Comparative analysis of the sequence data revealed the genus to consist of a number of distinct subdivisions. The most prevalent species associated with food spoilage, Z. bailii, Z. bisporus and Z. rouxii, along with Z. mellis were found to form one subdivision. Zygosaccharomyces cidri and Z. fermentati formed a distinct species pair, as did Z. microellipsoides and Z. mrakii. Zygosaccharomyces florentinus formed a separate line displaying no specific relationship with any of the other Zygosaccharomyces species examined. Comparison with nine published ascosporogenous yeast 18S rRNA gene sequences showed that Z. microellipsoides and Z. mrakii were genealogically very close to Torulaspora delbrueckii (both displaying 99.8% 18S rRNA sequence similarity), raising the possibility that these two Zygosaccharomyces species should be moved to the genus Torulaspora. The topologies of trees derived from complete 18S rRNA gene sequences and from individual domains within the gene were compared and the implications of using partial sequence data for inferring phylogenetic relationships discussed.

Association between maternal education and infant diarrhea in different household and community environments of Cebu, Philippines

Maternal education is one of the strongest determinants of infant survival in developing countries, however, questions remain regarding the extent to which its effects vary as a function of contextual variables. In this study, a multi-level interactive model is used to assess whether the protective effect of maternal education on the risk of infant diarrhea is modified by three aspects of the mother's familial and community environment: household assets, community economic resources and the availability of mothers' clubs. 2484 study participants were interviewed in 1984 as part of the Cebu Longitudinal Infant Health and Nutrition Study. The findings suggest that the protective effect of maternal education on infant diarrhea varies according to the socio-economic environment in which the mother lives: maternal education protects against infant diarrhea in the more economically and socially advantaged communities but has no effect in the more disadvantaged communities. The results also indicate that the protective effect of maternal education is smaller in the wealthier households. These data suggest that improvement in maternal education level, alone, may not always have the expected beneficial effects on infant health. Corollary measures to improve access of mothers and children to basic community resources and efforts to help mothers be more effective in their various social roles may be necessary preconditions for higher levels of maternal education to result in improved infant health.