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PubMed1997

Histomorphometric assessment of bone mass, structure, and remodeling: a comparison between healthy black and white premenopausal women.

While noninvasive studies of bone mass and turnover in blacks and whites abound, histologic evaluations are very rare. We have performed a comparative bone histomorphometric study of iliac biopsies from 55 healthy, premenopausal women including 21 blacks (mean age 33.4 + 1.2 years) and 34 whites (mean age 32.5 + 0.8 years) of comparable age, weight, body composition, education, and lifestyle. Biochemical indices of mineral metabolism: parathyroid hormone, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, serum ionized calcium, serum phosphorus, and urinary calcium/creatinine were measured in the fasting state. Blacks had lower 25-hydroxyvitamin D (315 +/- 3.36 vs. 63.21 +/- 3.79 nmol/l, p = 0.0001). Histomorphometric indices of bone volume, structure, and connectivity were not different between groups. The following indices of bone remodeling were also similar in both groups: eroded perimeter, osteoid width, mineralizing perimeter, tissue-based bone formation rate, osteoid maturation time, active formation period, and activation frequency. However, osteoid perimeter (black [B] = 15.85 +/- 1.30 vs. white [W] = 9.49 +/- 0.70%, p = 0.0002), osteoid area (B = 2.55 +/- 0.32 vs. W = 1.39 +/- 0.12%, p = 0.003), single-labeled perimeter (B = 5.46 +/- 0.54 vs. W = 4.04 +/- 0.33%, p = 0.03), mineralization lag time (B = 38.18 +/- 4.04 vs. W = 21.83 +/- 1.60 days, p < 0.009), and total formation period (B = 148.15 +/- 19.70 vs. W = 84.04 +/- 7.62 days, p = 0.0056) were higher in blacks than in whites. The quiescent perimeter (B = 76.91 +/- 1.40 vs. W = 84.25 +/- 0.91%, p = 0.0001), mineral apposition rate (B = 0.70 +/- 0.02 vs. W = 0.75 +/- 0.02 micron/day, p = 0.066), mineralizing osteoid perimeter (B = 0.49 +/- 0.04 vs. W = 0.75 +/- 0.04%, p = 0.0001) and adjusted apposition rate (B = 0.35 +/- 0.04 vs. W = 0.58 +/- 0.04 micron3/micron2/day, p = 0.0001) were all lower in blacks than in whites. These results indicate that there are no differences in bone volume, microstructure, or turnover between black and white premenopausal women. However, there are significant differences in the mechanism of bone formation between the two groups, with a lower rate of mineralized matrix apposition within each remodeling unit and a longer total formation period in blacks than in whites. The differences appear to the result of more frequent and/or longer inactive periods in the life span of the bone formation units in blacks. These differences may allow a greater overall deposition of bone mineral in black women and therefore help explain a higher bone mass and perhaps better bone quality in black than white women.

Adult↗
PubMed2005

Body image and attitude toward obesity in an historically black university.

INTRODUCTION: The obesity epidemic is a major problem in the United States, particularly among black women. Body image and attitudes toward obesity are important areas to understand and address in any comprehensive approach to this epidemic. METHODS: From an initial evaluation of 200 college students (25 male and 25 female freshmen, sophomores, juniors and seniors each) attending an historically black university, we selected those students who identified themselves as black for data analysis (n = 191). All students underwent height and weight measurement from which body mass index (BMI) was calculated. Each student answered two questions related to nine silhouettes for each sex that progressively moved from extreme thinness to extreme obesity. Also, each student answered 20 questions describing attitudes about obesity. RESULTS: Black college students placed between the 62nd and 72nd percentiles of national BMI data for adolescents. Black female students were more likely than their black male counterparts to be obese. BMI did not vary by sex or grade level. Students of both sexes generally preferred "trim" silhouettes with the caveat that students with BMIs <25 kg/m2 preferred smaller silhouettes than did students with BMIs > or =25 kg/m2. BMI and sex did not favor any particular set of attitudes toward obesity. CONCLUSION: Black male and female college students from an historically black university were largely in the "normal" range of BMI percentiles for sex and age. Our black female students were more likely to be obese than our black male students. Our findings suggest that young black women are tolerant of a variety of body sizes. Based on findings from our Attitudes Toward Obese Persons scale, body size sense of self and sex do not influence attitudes toward obese persons. Further studies are needed.

Adolescent↗
PubMed1987

Black-white differences in health status: methods or substance?

Apparent differences in the health status of blacks and whites vary according to methods of measurement, errors in the measurement process and interpretation of the measures, and types of measures used. This article uses the literature and secondary analysis of available data to explore the impact of methods on health status comparisons by race. Methods to measure health status include records, direct observations, and self-reports. Blacks generally show the greatest health deficits based on observation and least on some types of self-reports. Major types of errors in health status estimates are random errors and biases. Random errors tend to be greater for blacks because samples used to estimate their characteristics have often been smaller than white samples. Biases include noncoverage or failure to include some types of individuals in the reporting systems at all, nonresponse or lack of complete information on some persons, and use of inaccurate information due to faulty data collection or processing. Such biases tend to be greater for black persons than for whites. Their impact often is to give the illusion that blacks may be in better health than is actually the case. The types of measures that show blacks in the poorest health status are those considered to be most objective: mortality rates and some clinical examinations and health provider records. Subjective measures of dissatisfaction with health level also show blacks to be much less healthy than whites. In contrast, self-reports of illness conditions, symptoms, and restricted-activity days show blacks, particularly children, to be relatively well off compared to whites. These self-reports may be misleading due to differential perceptions of illness and reporting biases between blacks and whites. There is no doubt that measured differences in the health status of blacks and whites often reflect substance. There are also significant methodological problems, however, in comparing health status by race, which tend to underestimate the problems experienced by the black population. This article and others in this volume stress the need to know much more about the sources and impact of these methodological problems. In the meantime, these problems need to be recognized and adjusted for, where possible, when health status measures are compared. It is particularly important to consider them when policy questions of equity and resource allocation are to be decided using indicators of health status.

Black or African American↗
PubMedDate not supplied

On the decrease in the life expentancy of black males in Michigan.

The 1970 census reported that there were slightly more than 1 million nonwhites among Michigan's 8,875,000 residents. Ninety-five percent of these nonwhites are black, and 75 percent live within the city limits of Detroit, compared with 10 percent of the State's white residents. Between 1959-61 and 1969-71, life expectancy at birth increased about 1 year for black and white females, essentially remained unchanged for white males, and decreased more than 3 years for black males. In 1969-71, life expectancy was 61 years for black males, 68 years for white males, 69 years for black females, and 75 years for white females. Much of this growing disparity noted resulted from a dramatic rise in deaths of black males in the 15-44 year age group. Two-thirds of this increase was caused by a major rise in mortality from two causes--accidents and homicides. While death rates for black males decreased for a number of other leading causes, these generally remained higher than similar figures for each of the other three race-sex groups. Given current rates, one of eight black males in Michigan ultimately will die from an accident or from homicide. This probability is 1 of 17 for white males, 1 of 30 for white females, and 1 of 26 for nonwhite females. Homicides reduced the life expectancy of black males by 2.3 years, compared with 0.2 year for white males, less than 0.005 year for white females, and 0.5 year for black females. More than three-quarters of all homicides of black males in Michigan in 1973 were caused by handguns.

Accidents↗
PubMed1993

Black-white disparities in blunt trauma.

To uncover causes of increased mortality rates in black accident victims, patterns of injury and access to trauma care were compared between black and white patients. Over a 41-month period (February 1985 to June 1988), 2120 white and 468 black patients, each with an Injury Severity Score (ISS) > 14 as a result of blunt trauma, were admitted to a Level I regional trauma center, part of a statewide trauma system. Blacks were significantly older and more of them had premorbid illnesses. Although vehicular crashes accounted for the majority of injuries in both groups, blacks had significantly more injuries resulting from falls, pedestrian accidents, and assaults. Whereas 70.6% of whites were transported from the scene and 73% were transported by helicopter, 52.7% of blacks were transported from the scene and 44% by helicopter. Blacks made up 18% of the study group and accounted for 20% of deaths (mortality rate 17.3% for blacks and 14.9% for whites). Mortality was significantly increased for black patients admitted with a Glasgow Coma Scale (GCS) score > or = 13. Private medical insurance, available for 46.3% of black patients, accounted for 78% of payments for all trauma admissions. Increased mortality of black trauma patients may be related to risk factors (age, premorbid illness), increased rates of pedestrian accidents and falls, and disparities in access to Level I trauma centers.

Adolescent↗
PubMed1997

Higher frequency of glutathione S-transferase deletions in black children with acute lymphoblastic leukemia.

The genetic polymorphisms in human glutathione S-transferases (GST) M1 and T1 have been associated with race, disease risk, and outcome of some adult cancers. Also, there are racial differences in the incidence and characteristics of childhood acute lymphoblastic leukemia (ALL). Our objectives were to compare the frequency of the null genotype for GSTM1, GSTT1, or both in children with ALL to that in healthy controls, and to determine whether GST genotype was associated with treatment outcome and prognostic factors. We studied GSTM1 and GSTT1 genotypes in somatic cell DNA from black children and white children with ALL and in 416 healthy controls, using a polymerase chain reaction technique. Ninety of 163 (55.2%) white ALL patients and 14 of 34 (41.2%) black patients were GSTM1 null, frequencies not significantly different (P = .19) than healthy controls (53.5% in whites and 27.6% in blacks), although there was a trend toward more null genotypes in black ALL patients. Twenty-three of 163 (14.1%) white ALL patients and 12 of 34 (35.3%) black ALL patients were GSTT1 null, not different (P = .34) than the frequencies in healthy controls (15.0% in whites and 24.1% in blacks). However, the frequency of the "double-null" genotype, lacking both GSTM1 and GSTT1, was higher in black patients with ALL (8 of 34 or 23.5%) than in black controls (3.9%) (P = .0005), but this was not the case in white patients with ALL (10 of 163 or 6.1%) compared to white controls (8.0%) (P = .68). In stratified analyses, the GST double-null genotype was not associated with other characteristics that might differ between whites and blacks with ALL, such as age, T-lineage immunophenotype, presenting white blood cell count, DNA index, or insurance status. The null genotype for GSTM1, GSTT1, or both was not found to be a prognostic factor for disease-free survival or probability of hematologic remission; central nervous system relapse tended to be less common in those with the GSTM1 null genotype (P = .054). The double-null genotype for GSTM1 and GSTT1 is more common among blacks but not whites with childhood ALL. These data suggest that GST genotype, coupled with unidentified additional risk factors, may play a role in risk of childhood ALL in American blacks.

Adult↗
PubMed1997

Minisatellite DNA markers reveal hybridisation between the endangered black robin and tomtit.

We have used multilocus minisatellite DNA profiling to assess genetic variation in the endangered and highly inbred black robins and the closely related tomtits. These species are restricted to wild populations on the Chatham Islands, off the east coast of New Zealand. DNA profiles revealed a remarkable degree of genetic similarity among black robins, as well as among the tomtits sampled, although the typical profiles of these two species were clearly distinct. The parentage of two putative hybrid chicks and one putative hybrid adult was established for a 'black robin' adult male and an adult tomtit female which were found nesting together. The 'black robin' male, despite being morphologically a typical black robin, was found to possess a number of minisatellite-containing restriction fragments not recorded from the black robin population (n = 103). These fragments were however detected in tomtits. Consequently, this bird appeared to be an F1 hybrid and his three offspring were F2 hybrids. Mitochondrial DNA sequencing of members of this family showed that the 'black robin' male had cytochrome b and 16S of black robin, rather than tomtit, haplotypes. This indicates that the black robin adult male hybrid was the result of a black robin female mating with a tomtit male. These findings are particularly important since tomtits had been used as cross-foster parents for black robins, as part of an earlier conservation recovery program. The existence of any hybrids thus detected would have important implications for cross-fostering programs generally, since may such programs are now being implemented in conservation programs worldwide.

Amino Acid Sequence↗
PubMed2006

Fluoride levels in various black tea commodities: measurement and safety evaluation.

In order to determine the fluoride content of various products of black tea and to make safety evaluations, 37 commodities in the different manufactured forms of tea were assessed by means of ion-selective electrode and spectrophotometric methods. The results showed wide differences in fluoride levels. The fluoride content was found 0.95-1.41 mg/L in black tea sticks, 0.70-2.44 mg/L in black tea granules and 1.15-6.01 mg/L in black tea bags. Of the products tested, the fluoride content was greatest in black tea bags, presumably because black tea bags are made of low cost, and older tea leaves. According to WHO's recommendation, fluoride exposure threshold for children is 2mg of daily intake and for adult, 4 mg. Assuming that children's daily intake of black tea was 800 ml and adult's 1500 ml, 56% of black tea bags should be considered unsafe for children and 44% should be considered unsafe for adults. At average rates of consumption, 24% of the black tea bags could result in an increasing risk of osteofluorosis and fractures (WHO). In the areas with drinking water fluoridation or other fluoride supplements, excessive fluoride exposure can become even more severe with even lower intake tea made from black tea bags. The potential hazards of fluoride arising from consumption of black tea has not aroused due public attention. Therefore, it is necessary to establish reliable fluoride surveillance in food and beverage commodities and conduct additional epidemiological research on fluoride hazards. In addition, it is urgent that governmental and international agencies adopt safe standards of fluoride content in tea commodities.

Electrochemistry↗
PubMed2005

The Drosophila black enigma: the molecular and behavioural characterization of the black1 mutant allele.

The cuticular melanization phenotype of black flies is rescued by beta-alanine, but beta-alanine production, by aspartate decarboxylation, was reported to be normal in assays of black mutants, and although black/Dgad2 is expressed in the lamina, the first optic ganglion, no electroretinogram (ERG) or other visual defect has been demonstrated in black flies. The purpose of this study was to investigate the black gene, and protein, in black(1) mutants of Drosophila melanogaster in order to resolve the apparent paradox of the black phenotype. Using black(1) mutant flies we show that (1) aspartate decarboxylase activity is significantly reduced in adults and at puparium formation, consistent with defects in cuticular and non-cuticular processes, (2) that the black(1) mutation is a frameshift, and black(1) flies are nulls for the black/DGAD2 protein, and (3) that behavioural experiments using Buridan's paradigm, demonstrate that black responds abnormally to visual cues. No ERG, or target recognition defects can be demonstrated suggesting a problem with higher order visual functions in black mutants.

Alleles↗
PubMed1999

Scavenging of hydrogen peroxide and inhibition of ultraviolet light-induced oxidative DNA damage by aqueous extracts from green and black teas.

Aqueous extracts of green and black teas have been shown to inhibit a variety of experimentally induced animal tumors, particularly ultraviolet (UV) B light-induced skin carcinogenesis. In the present study, we compared the effects of different extractable fractions of green and black teas on scavenging hydrogen peroxide (H2O2), and UV irradiation-induced formation of 8-hydroxy 2'-deoxyguanosine (8-OHdG) in vitro. Green and black teas have been extracted by serial chloroform, ethyl acetate and n-butanol, and divided into four subfractions designated as GT1-4 for green tea and BT1-4 for black tea, respectively. The total extracts from green and black teas exhibited a potent scavenging capacity of exogenous H2O2 in a dose-dependent manner. It appeared that the total extracts from black tea scavenged H2O2 more potently than those from green tea. When tested individually, the potency of scavenging H2O2 by green tea subfractions was: GT2 > GT3 > GT1 > GT4, whereas the order of efficacy for black tea was: BT2 > BT3 > BT4 > BT1. In addition, we demonstrated that total fractions of green and black teas substantially inhibited the induction of 8-OHdG in calf thymus by all three portions of UV spectrum (UVA, B and C). Consistent with the capacity of scavenging H2O2, the subfractions from black tea showed a greater inhibition of UV-induced 8-OHdG than those from green tea. At low concentrations, the order of potency of quenching of 8-OHdG by green tea subfractions was: GT2 > GT3 > GT4 > GT1 and the efficacy of all subfractions became similar at high concentrations. All subfractions of the black tea except BT1 strongly inhibited UV-induced 8-OHdG and the order of potency was: BT2 > BT3 > BT4 > BT1. Addition of (-)-epigallocatechin gallate (EGCG), an ingredient of green tea extract, to low concentration of green and black tea extracts substantially enhanced the scavenging of H2O2 and quenching of 8-OHdG, suggesting the important role of EGCG in the antioxidant activities of tea extracts. The potent scavenging of oxygen species and blocking of UV-induced oxidative DNA damage may, at least in part, explain the mechanism(s) by which green/black teas inhibit photocarcinogenesis.

Carcinogenicity Tests↗
PubMed2003

Comparison of adipose tissue fatty acids with dietary fatty acids as measured by 24-hour recall and food frequency questionnaire in Black and White Adventists: the Adventist Health Study.

PURPOSE: To calibrate and compare intake of different fats and individual fatty acids as assessed with a food frequency questionnaire (FFQ) against that estimated with (i) a series of dietary recalls and; (ii) the relative fat concentration in an adipose tissue biopsy. The FFQ was specially designed for use in a cohort of Seventh-day Adventists. In preparation for a large cohort study investigating the effect of diet on risk of colon, prostate and breast cancer. METHODS: The association of adipose tissue fatty acids and dietary fat intake was assessed in 49 black and 72 white Seventh-day Adventists subjects using 8 different 24-hour recalls, a 200-item food frequency questionnaire (FFQ) and adipose tissue biopsies from each subject. RESULTS: Pearson correlation between fatty acids in adipose tissue and dietary intake as assessed by multiple 24-hour recalls were as follows: Linoleic acid: 0.77 in black and 0.71 in white subjects, respectively; Linolenic acid: 0.68 (blacks) and 0.62 (whites); Total Polyunsaturated fat (PUFA): 0.78 (blacks) and 0.70 (whites); Total Monounsaturated fat (MUFA): 0.35 (blacks) and 0.03 (whites); Total Saturated fat (SFA): 0.46 (blacks) and 0.56 (whites). Correlations between fatty acids in adipose tissue and dietary intake as assessed by FFQ were: Linoleic acid: 0.61 (blacks) and 0.52 (whites), respectively; Linolenic acid: 0.29 (blacks) and 0.49 (whites); PUFA: 0.62 (blacks) and 0.53 (whites); MUFA: 0.07 (blacks) and 0.31 (whites), SFA: 0.21 (blacks) and 0.31 (whites). CONCLUSIONS: Our study confirms findings of others that 24-hour recalls are valid for assessing dietary intake of different types of fat. The FFQ we developed and used in this study gave reasonably valid measures of fatty acid intake in our population and is thus suitable for use in large cohort studies. It had validity comparable to that observed for other FFQs.

Adipose Tissue↗
PubMed2003

In vitro formation of quinoid metabolites of the dietary supplement Cimicifuga racemosa (black cohosh).

Botanical dietary supplements containing Cimicifuga racemosa (Actaea racemosa; black cohosh) are used commonly by women to assuage menopausal symptoms including hot flashes and sleep disorders. Despite the popularity of such supplements, little is known about the metabolism or possible toxicity of many compounds that could be concentrated therein. The aim of this study was to selectively identify phase I metabolites resulting from metabolic bioactivation of constituents of black cohosh in vitro and to determine whether evidence of such metabolites could be found in the urine of perimenopausal women taking black cohosh oral supplements. A variation of an ultrafiltration mass spectrometric assay devised previously was used to screen an extract of black cohosh for the formation of electrophilic phase I metabolites that had been trapped as GSH conjugates. Mercapturates (N-acetylcysteine conjugates) corresponding to the GSH conjugates identified during screening were synthesized and characterized using LC-MS/MS with product-ion scanning. During a phase I clinical trial of black cohosh in perimenopausal women, urine was collected from seven subjects, each of whom took a single oral dose of either 32, 64, or 128 mg of the black cohosh extract. These urine samples were analyzed for the presence of mercapturate conjugates using positive-ion electrospray LC-MS and LC-MS/MS. On the basis of their propensity to form GSH adducts following metabolic activation by hepatic microsomes and NADPH in vitro, a total of eight electrophilic metabolites of black cohosh were detected, including quinoid metabolites of fukinolic acid, fukiic acid, caffeic acid, and cimiracemate B. Additional quinoid metabolites were formed from hydroxytyrosol and dihydroxyphenyl lactic acid, neither of which had been isolated previously from black cohosh. However, mercapturate conjugates of these black cohosh constituents were not detected in urine samples from women who consumed single oral doses of up to 256 mg of a standardized black cohosh extract. Therefore, for moderate doses of a dietary supplement containing black cohosh, this study found no cause for safety concerns over the formation of quinoid metabolites in women.

Acetaminophen↗
PubMed2005

The formation of bulges and black holes: lessons from a census of active galaxies in the SDSS.

We examine the relationship between galaxies, supermassive black holes and AGN using a sample of 23,000 narrow-emission-line ('type 2') active galactic nuclei (AGN) drawn from a sample of 123,000 galaxies from the Sloan Digital Sky Survey. We have studied how AGN host properties compare with those of normal galaxies and how they depend on the luminosity of the active nucleus. We find that AGN reside in massive galaxies and have distributions of sizes and concentrations that are similar to those of the early-type galaxies in our sample. The host galaxies of low-luminosity AGN have stellar populations similar to normal early types. The hosts of high- luminosity AGN have much younger mean stellar ages, and a significant fraction have experienced recent starbursts. High-luminosity AGN are also found in lower-density environments. We then use the stellar velocity dispersions of the AGN hosts to estimate black hole masses and their [OIII]lambda5007 emission-line luminosities to estimate black hole accretion rates. We find that the volume averaged ratio of star formation to black hole accretion is approximately 1000 for the bulge-dominated galaxies in our sample. This is remarkably similar to the observed ratio of stellar mass to black hole mass in nearby bulges. Most of the present-day black hole growth is occurring in black holes with masses less than 3 x 10(7)M(3). Our estimated accretion rates imply that low-mass black holes are growing on a time-scale that is comparable with the age of the Universe. Around 50% this growth takes place in AGN that are radiating within a factor of five of the Eddington luminosity. Such systems are rare, making up only 0.2% of the low-mass black hole population at the present day. The remaining growth occurs in lower luminosity AGN. The growth time-scale increases by more than an order of magnitude for the most massive black holes in our sample. We conclude that the evolution of the AGN luminosity function documented in recent optical and X-ray surveys is driven by a decrease in the characteristic mass scale of actively accreting black holes.

Astronomy↗
PubMed2006

Effect of Black maca (Lepidium meyenii) on one spermatogenic cycle in rats.

Lepidium meyenii (Maca) grows exclusively between 4000 and 4500 m above sea level in the Peruvian central Andes. The hypocotyls of this plant are traditionally used in the Andean region for their supposed fertility-enhancing properties. The hypocotyls have different colours. Of these, Black maca has better effects on spermatogenesis. The present study aimed to test the hypothesis that Black maca has early effects during a spermatogenic cycle (12 days) of male rats. For this, testicular spermatid, epididymal sperm and vas deferens sperm counts were measured after 1, 3, 5, 7 and 12 days of treatment with Black maca. Aqueous extract of Black maca was given orally by daily gavage at a dose of 2 g kg(-1). In a spermatogenic cycle, compared with day 1, daily sperm production (DSP) was lower at day 7 (control), whereas with Black maca, the difference was observed at day 12. Epididymal sperm count was higher in rats treated with Black maca at days 1, 3 and 7, but similar to controls at days 5 and 12; similarly sperm counts in vas deferens was higher in rats treated with Black maca in days 3, 5 and 7, but similar to controls at days 1 and 12. From this, it is suggested that first action of Black maca was at epididymal level increasing sperm count after 1 day of treatment, whereas an increase in sperm count was observed in vas deferens at day 3 of treatment. Finally, an increase in DSP was observed after 7 days of treatment with Black maca. Testicular testosterone was not affected after 7 days treatment with Black maca. In conclusion, Black maca affects sperm count as early as 1 day after beginning of treatment.

Animals↗
PubMed2001

The "black hole" phenomenon in ultrasonic backscattering measurement under pulsatile flow with porcine whole blood in a rigid tube.

The "black hole" phenomenon was further investigated with porcine whole blood under pulsatile flow conditions in a straight rigid tube 120 cm long and of 0.95 cm diameter. A modified Aloka 280 commercial scanner with a 7.5 MHz linear array was used to collect the radio frequency (RF) signal of backscattering echoes from the blood inside the tube. The transducer was located downstream from the entrance and parallel to the longitudinal direction of the tube. The experimental results showed that higher hematocrits enhanced the black hole phenomenon, leading to a more apparent and larger diameter black hole. The black hole was not apparent at hematocrits below 23%. The highest hematocrit used in the experiment was 60%. Beat rates of 20, 40 and 60 beats per minute (bpm) were used, and the black hole became weaker in amplitude and smaller in diameter when the peak flow velocity was increased at each beat rate. These results are consistent with the suggestion in previous work that the black hole arises from insufficient aggregation of red blood cells (RBCs) at the center of the tube because of the low shear rate. At 20 and 40 bpm, the peak flow velocity ranges were 10 approximately 25 cm/s and 18 approximately 27 cm/s, respectively. The black hole was very clear at the minimal peak flow velocity but almost disappeared at the maximal velocities for each beat rate. At 60 bpm, experiments were only performed at one peak flow velocity of 31 cm/s and the black hole was clear. The results showed that the black hole was more pronounced at higher beat rates when the peak velocity was the same. This phenomenon cannot be explained by previous hypotheses. Acceleration seems to be the only flow parameter that varies at different beat rates when peak velocities are the same. Therefore, the influence of acceleration on the structural organization and orientation of RBC rouleaux might be another factor involved in the formation of the black hole in addition to the shear rate. As the entrance length was changed from 110 to 15 diameters (D) in seven steps at the hematocrit of 60%, it was found that a position farther downstream yielded a black hole with a greater contrast relative to the surrounding region, while the backscattering power at the central hypoechoic zone did not increase with increasing entrance length.

Animals↗
PubMed2001

Mucin gene expression in gallbladder epithelium with black pigment stone ascertained by in situ hybridization.

Black pigment stones are usually found in patients with liver cirrhosis or hemolytic disease. Mucoglycoproteins are present in a significant amount in black pigment stones and contribute to the matrix of gallstones. Epithelium of stone-containing gallbladders contains much more mucin than those without stones. In this study, we try to determine by in situ hybridization the mucin gene expression in black stone-containing gallbladders and try to find the diversity of mucin gene expression in gallbladders containing black pigment stones and those without stones. In situ hybridization with DIG-tailed oligonucleotides was performed on sections of paraffin-embedded tissues of gallbladders with black pigment stones (n = 10) and those without stones (n = 6) to identify the expression of MUC1, MUC2, MUC3, MUC4, MUC5B and MUC6 in gallbladder epithelium. The findings showed that (1) mRNA expression of MUC1, MUC3, MUC5B and MUC6 were found in all gallbladders with black pigment stones, while they were expressed in 33.3%, 83.3%, 83.3% and 66.7% respectively in those without stones. They were expressed more strongly and extensively in gallbladders with stones when compared to those without stones. (2) MUC2 and MUC4 labeling were absent in gallbladders without stones, while they were present in 20% and 60% of gallbladders with black pigment stones, respectively. We conclude that MUC3, MUC5B and MUC6 were the main mucin gene expression in either gallbladder with or without stones. Altered mucin gene expression occurred in gallbladders with black pigment stones, such as the presence of MUC2 and MUC4 and increased expression of MUC1, MUC3, MUC5B and MUC6 in black stone-containing gallbladders. The higher incidence and stronger labeling intensity of mucin gene expression of MUC2, MUC3, MUC5B and MUC6 in black stone-containing gallbladder may reflect abundant mucin content in these gallbladders. Increased expression of MUC2 and MUC4 in black stone-containing gallbladder epithelium indicated that intestinal metaplasia and altered mucin genes could occur in diseased gallbladders.

Adult↗
PubMed2006

[Melanin traits of Yunnan black bone sheep and TYR gene polymorphism].

The "black bone and muscle" is cardinal melanin trait of black bone sheep. The black bone sheep and the native sheep in Lanping and Luomuni sheep were chosen as materials for the measurement of TYR activity of blood and melanin content of tissues and organs. Moreover, we compared characteristic structure of melanin of black bone sheep with silky fowls. The results showed as follows: TYR activity was significantly different between black and non-black bone sheep (P<0.05); the total character of infrared spectrum (IR) of melanin of black bone sheep resembled silky fowls; and melanin was eumelanin. We firstly cloned exon1 667bp sequence of TYR gene and determined TYR gene polymorphism of black and non-black bone sheep by PCR-RFLP. Compared with sequence of TYR gene of non-black bone sheep, there were two nucleotide mutation sites in exon1 of black bone sheep, located in No.64 and No.154 amino acid codons, respectively; but they were synonymics mutation. We designed restriction site in codon 64 and check up TYR gene polymorphism. The result showed the mutation site together with the close linked gene influenced melanin trait deposition. It suggests there should be functional mutation related with melanin trait. Furthermore, there was significant correlation between TYR gene polymorphism and coat color of sheep (P<0.01), indicating TYR could influence synthesis of coat color of sheep.

Animals↗
PubMed2006

Prevalence of and risk factors for lifetime suicide attempts among blacks in the United States.

CONTEXT: Lack of data on the lifetime prevalence and age at onset of suicide ideation, plans, and attempts among blacks in the United States limits the creation and evaluation of interventions to reduce suicide among black Americans. OBJECTIVE: To examine the prevalence and correlates of suicide ideation, planning, and attempts across 2 ethnic classifications of blacks in a nationally representative sample. DESIGN, SETTING, AND PARTICIPANTS: Data are from the National Survey of American Life, a national household probability sample of 5181 black respondents aged 18 years and older, conducted between February 2001 and June 2003, using a slightly modified adaptation of the World Health Organization World Mental Health version of the Composite International Diagnostic Interview. Bivariate and survival analyses were used to delineate patterns and correlates of nonfatal suicidal behavior. MAIN OUTCOME MEASURES: Self-reports of lifetime suicide ideation, planning, and attempts. RESULTS: Survey respondents, categorized as African Americans and Caribbean Americans, reported lifetime prevalence of 11.7% for suicide ideation and 4.1% for attempts. Among the respondents who reported ideation, 34.6% transitioned to making a plan and only 21% made an unplanned attempt. Among 4 ethnic-sex groups, the 7.5% lifetime prevalence for attempts among Caribbean black men was the highest among black Americans. The greatest risk of progressing to suicide planning or attempt among ideators occurred within the first year after ideation onset. Blacks at higher risk for suicide attempts were in younger birth cohorts, less educated, Midwest residents, and had 1 or more Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition disorders. CONCLUSIONS: This study documents the burden of nonfatal suicidality among US blacks, notably Caribbean black men, and individuals making planned attempts. Advancing research on the transition from suicide planning to attempt is vital to the efficacy of health care professionals' ability to screen blacks at risk for suicide.

Adult↗