Biomedical subjects

R Yip

Publications and source records attributed to R Yip.

At least 19 recordsLinked to original sources

PubMed2004

Oyster-associated outbreaks of Norovirus gastroenteritis in Singapore.

Outbreaks of gastroenteritis associated with the consumption of raw imported half-shelled frozen oysters occurred in Singapore between 16 Dec 2003 and 04 Jan 2004. A total of 305 cases were reported with clinical symptoms of diarrhoea (94%), abdominal cramps (72%), vomiting (69%) and fever (54%). The median incubation period was 30.8h and the duration of illness was 2-3 days. The overall relative risk of oyster consumption was 14.1 (95% CI: 8.3-24.0, P<0.001). Stool and oyster samples tested negative for common bacterial pathogens, including Vibrio parahaemolyticus. However, stool samples were positive for the presence of Norovirus group II RNA via RT PCR while oyster samples indicated the presence of Norovirus particles by electron microscopy. The clinical and epidemiological features were suggestive of Norovirus gastroenteritis and were subsequently confirmed by laboratory tests of stools and implicated oysters. Steps have been taken to ensure that food outlets do not thaw frozen oysters and serve them raw.

Adolescent↗

PubMed2003

Differential decline in tuberculosis incidence among US- and non-US-born persons in New York City.

SETTING: A large urban tuberculosis control program. OBJECTIVES: To examine changes in tuberculosis incidence and characteristics of cases in New York City (NYC), and assess the epidemiology of tuberculosis among non-US-born persons. DESIGN: Tuberculosis surveillance data (1995-1999) for NYC were analyzed. RESULTS: Tuberculosis incidence decreased by 56.6% in US-born and 19.6% in non-US-born persons (age-adjusted) over the study period. The decline in tuberculosis incidence among US-born persons was more substantial in the first half of the study period (23-24%) than in the second half (13-15%). The greatest decline in incidence was among US-born Hispanic or Black males aged 25-64. However, although there was an overall decline in incidence among non-US-born persons, there was no significant change in any sex or racial/ethnic subgroup. The percent of multidrug-resistant (MDR) cases among non-US-born patients remained stable, but recent arrivals accounted for 79% of non-US-born MDR-TB patients in 1999, a significant increase from 16% in 1997. CONCLUSIONS: Continuing current tuberculosis control efforts and treatment of immigrants with latent tuberculosis infection are of highest priority for reducing incident cases in NYC. Global collaboration towards earlier detection and treatment of active tuberculosis cases in high incidence countries is also essential.

Adult↗

PubMed2001

Mutations in Mlph, encoding a member of the Rab effector family, cause the melanosome transport defects observed in leaden mice.

The d, ash, and ln coat color mutations provide a unique model system for the study of vesicle transport in mammals. All three mutant loci encode genes that are required for the polarized transport of melanosomes, the specialized, pigment-containing organelles of melanocytes, to the neighboring keratinocytes and eventually into coat hairs. Genetic studies suggest that these genes function in the same or overlapping pathways and are supported by biochemical studies showing that d encodes an actin-based melanosome transport motor, MyoVa, whereas ash encodes Rab27a, a protein that localizes to the melanosome and is postulated to serve as the MyoVa receptor. Here we show that ln encodes melanophilin (Mlph), a previously undescribed protein with homology to Rab effectors such as granuphilin, Slp3-a, and rabphilin-3A. Like all of these effectors, Mlph possesses two Zn(2+)-binding CX(2)CX(13,14)CX(2)C motifs and a short aromatic-rich amino acid region that is critical for Rab binding. However, Mlph does not contain the two Ca(2+)-binding C(2) domains found in these and other proteins involved in vesicle transport, suggesting that it represents a previously unrecognized class of Rab effectors. Collectively, our data show that Mlph is a critical component of the melanosome transport machinery and suggest that Mlph might function as part of a transport complex with Rab27a and MyoVa.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Socio-economic status and puberty are the main factors determining anaemia in adolescent girls and boys in East Java, Indonesia.

OBJECTIVE: To determine prevalence and contributing factors of anaemia in adolescents. DESIGN: Cross-sectional study of anaemia prevalence, socio-economic status and puberty. SETTING: Schools in East Java, Indonesia. SUBJECTS: Male and female adolescent pupils (age 12-15 y; n=6486). RESULTS: Anaemia prevalence was 25.8% among girls (n=3486), 24.5% among pre-pubertal boys (n=821), and 12.1% among pubertal boys (n=2179). Socio-economic status, indicated by type of school attended, was an important factor determining the risk of anaemia. Girls had a higher risk when they attended a poor school (OR poorest school, 1.00; other schools, 0.67-0.87), had reached puberty (OR, 1.25), had lower retinol intake (OR 1st-4th quartiles-1.00, 0.97, 0.89, 0.77) and higher vitamin A intake from plant sources (OR 1st-4th quartiles-1.00, 1.10, 1.31, 1.04). Boys had a higher risk of anaemia when they attended a poor school (OR poorest school 1.00, other schools 0.54-0.63), were younger (OR per year=0.79), had not yet reached puberty (OR not yet, 1.00; already, 0.78), were shorter (OR per cm 0.95), had smaller mid-upper-arm circumference (MUAC) (OR per mm 0.99) and lower retinol intake (OR 1st-4th quartile 1.00, 0.67, 0.74, 0.68). CONCLUSIONS: Anaemia in adolescents should be reported separately for pre-pubertal and pubertal subjects and for different ages, and the population's socio-economic status should be specified. The results of this survey call for treatment of anaemia in adolescents. Given Indonesia's current situation, micronutrient intake of adolescents should be increased using supplements for all girls and for pre-pubertal boys. SPONSORSHIP: This survey was funded by USAID through the OMNI project.

Adolescent↗

PubMed2001

Uncommon hand tumours.

This paper presented clinical examples of some rare or uncommon presentations of tumours of the hand, including glomus tumour, intraosseous dermoid, fibrolipoma of the radial nerve, blastomycotic cyst and synovial sarcoma. Each lesion is illustrated by review of case histories, radiological and pathological features.

Adult↗

PubMed2001

Continuation of the decline in prevalence of anemia in low-income infants and children in five states.

OBJECTIVE: To examine whether there is a continuation of the decline in prevalence of anemia among low-income infants and children 6.0 to 59.9 months old from the early 1980s to the mid-1990s. STUDY DESIGN: Cross-sectional trend analysis of data from the Centers for Disease Control and Prevention's Pediatric Nutrition Surveillance System from the 5 states (Colorado, New Mexico, Oklahoma, Utah, and Vermont) that have been using the same laboratory method for anemia screening since 1984 or earlier. RESULTS: The overall prevalence of anemia decreased substantially in each state from the early 1980s to the mid-1990s as follows: Colorado by 52%; New Mexico by 75%; Oklahoma by 67%; Utah by 57%; and Vermont by 48%. In each state, the prevalence of anemia declined for children of different age groups, birth weights, genders, type of pediatric care visit (screening or follow-up), and most race/ethnic groups. CONCLUSIONS: The decline in the prevalence of anemia initially observed in the 1980s continued well into the 1990s. This decline is likely attributable to better iron nutrition related to greater usage of iron-fortified products and possibly better iron bioavailability in some of the food products.

Anemia↗

PubMed2001

Estimating the prevalence of anaemia: a comparison of three methods.

OBJECTIVE: To determine the most effective method for analysing haemoglobin concentrations in large surveys in remote areas, and to compare two methods (indirect cyanmethaemoglobin and HemoCue) with the conventional method (direct cyanmethaemoglobin). METHODS: Samples of venous and capillary blood from 121 mothers in Indonesia were compared using all three methods. FINDINGS: When the indirect cyanmethaemoglobin method was used the prevalence of anaemia was 31-38%. When the direct cyanmethaemoglobin or HemoCue method was used the prevalence was 14-18%. Indirect measurement of cyanmethaemoglobin had the highest coefficient of variation and the largest standard deviation of the difference between the first and second assessment of the same blood sample (10-12 g/l indirect measurement vs 4 g/l direct measurement). In comparison with direct cyanmethaemoglobin measurement of venous blood, HemoCue had the highest sensitivity (82.4%) and specificity (94.2%) when used for venous blood. CONCLUSIONS: Where field conditions and local resources allow it, haemoglobin concentration should be assessed with the direct cyanmethaemoglobin method, the gold standard. However, the HemoCue method can be used for surveys involving different laboratories or which are conducted in relatively remote areas. In very hot and humid climates, HemoCue microcuvettes should be discarded if not used within a few days of opening the container containing the cuvettes.

Anemia↗

PubMed2001

Better use of data to define nutrition priority and action.

Nutrition and dietary survey data has been useful in defining the magnitude of malnutrition and dietary deficit. Such information has been helpful in gaining attention to support or to do more to improve nutrition-advocacy. However, there are also greater opportunities to use the common data to guide the program action. In summary, we have plenty of good nutrition and dietary information available to us in the planning and operation of nutrition intervention program. If we go beyond the use of data to justify area or subject of engagement, we can also use the same data for more efficient and more effective program without additional cost to us.

Data Collection↗

PubMed2000

A mutation in Rab27a causes the vesicle transport defects observed in ashen mice.

The dilute (d), leaden (ln), and ashen (ash) mutations provide a unique model system for studying vesicle transport in mammals. All three mutations produce a lightened coat color because of defects in pigment granule transport. In addition, all three mutations are suppressed by the semidominant dilute-suppressor (dsu), providing genetic evidence that these mutations function in the same or overlapping transport pathways. Previous studies showed that d encodes a major vesicle transport motor, myosin-VA, which is mutated in Griscelli syndrome patients. Here, using positional cloning and bacterial artificial chromosome rescue, we show that ash encodes Rab27a. Rab GTPases represent the largest branch of the p21 Ras superfamily and are recognized as key players in vesicular transport and organelle dynamics in eukaryotic cells. We also show that ash mice have platelet defects resulting in increased bleeding times and a reduction in the number of platelet dense granules. These defects have not been reported for d and ln mice. Collectively, our studies identify Rab27a as a critical gene for organelle-specific protein trafficking in melanocytes and platelets and suggest that Rab27a functions in both MyoVa dependent and independent pathways.

Albinism, Oculocutaneous↗

PubMed2000

High and low hemoglobin levels during pregnancy: differential risks for preterm birth and small for gestational age.

OBJECTIVE: To examine the association of maternal hemoglobin during pregnancy with preterm birth and small for gestational age (SGA). METHODS: We performed a retrospective cohort analysis of hemoglobin and birth outcome among 173,031 pregnant women who attended publicly funded health programs in ten states and delivered a liveborn infant at 26-42 weeks' gestation. We defined preterm as less than 37 weeks' gestation and SGA as less than the tenth percentile of a US fetal growth reference. RESULTS: Risk of preterm birth was increased in women with low hemoglobin level in the first and second trimester. The odds ratio (OR) for preterm birth with moderate-to-severe anemia during the first trimester (more than three standard deviations [SD] below reference median hemoglobin, equivalent to less than 95 g/L at 12 weeks' gestation) was 1.68 (95% confidence interval [CI] 1.29, 2. 21). Anemia was not associated with SGA. High hemoglobin level during the first and second trimester was associated with SGA but not preterm birth. The ORs for SGA in women with very high hemoglobin level during the first and second trimester (more than three SDs above reference median hemoglobin, equivalent to greater than 149 g/L at 12 weeks' gestation and greater than 144 g/L at 18 weeks') were 1.27 (95% CI 1.02, 1.58) and 1.79 (95% CI 1.49, 2.15), respectively. CONCLUSION: These data highlight the importance of considering anemia and high hemoglobin level as indicators for adverse pregnancy outcome. An elevated hemoglobin level (greater than 144 g/L) is an indicator for possible pregnancy complications associated with poor plasma volume expansion, and should not be mistaken for good iron status.

Adolescent↗

PubMed2000

Significance of an abnormally low or high hemoglobin concentration during pregnancy: special consideration of iron nutrition.

An association between moderate anemia and poor perinatal outcomes has been found through epidemiologic studies, although available evidence cannot establish this relation as causal. Anemia may not be a direct cause of poor pregnancy outcomes, except in the case of maternal mortality resulting directly from severe anemia due to hypoxia and heart failure. Preventing or treating anemia, whether moderate or severe, is desirable. Because iron deficiency is a common cause of maternal anemia, iron supplementation is a common practice to reduce the incidence of maternal anemia. Nevertheless, the effectiveness of large-scale supplementation programs needs to be improved operationally and, where multiple micronutrient deficiencies are common, supplementation beyond iron and folate can be considered. High hemoglobin concentrations are often mistaken as adequate iron status; however, high hemoglobin is independent of iron status and is often associated with poor health outcomes. Very high hemoglobin concentrations cause high blood viscosity, which results in both compromised oxygen delivery to tissues and cerebrovascular complications. Epidemiologic studies have also found an association between high maternal hemoglobin concentrations and an increased risk of poor pregnancy outcomes. Evidence does not suggest that this association is causal; it could be better attributed to hypertensive disorders of pregnancy and to preeclampsia. The pathophysiologic mechanism of these conditions during pregnancy can produce higher hemoglobin concentrations because of reduced normal plasma expansion and cause fetal stress because of reduced placental-fetal perfusion. Accordingly, higher than normal hemoglobin concentrations should be regarded as an indicator of possible pregnancy complications, not necessarily as a sign of adequate iron nutrition, because iron supplementation does not increase hemoglobin higher than the optimal concentration needed for oxygen delivery.

Anemia, Iron-Deficiency↗

PubMed1999

A survey of 2,851 patients with hemochromatosis: symptoms and response to treatment.

PURPOSE: Hemochromatosis is a genetic disorder of iron absorption that affects 5 per 1,000 persons and is associated with reduced health and quality of life. We sought to determine the type and frequency of symptoms that patients experienced before the diagnosis and the treatments that they received. METHODS: We mailed a questionnaire to 3,562 patients with hemochromatosis who were located using patient advocacy groups, physicians, blood centers, newsletters, and the Internet. RESULTS: Of the 2,851 respondents, 99% were white and 62% were men. Circumstances that led to diagnosis of hemochromatosis included symptoms (35%), an abnormal laboratory test (45%), and diagnosis of a family member with hemochromatosis (20%). The mean (+/- SD) age of symptom onset was 41 +/- 14 years. Symptoms had been present for an average of 10 +/- 10 years before the diagnosis was made. Among the 58% of patients with symptoms, 65% had physician-diagnosed arthritis and 52% had liver disease. The most common and troublesome symptoms were extreme fatigue (46%), arthralgia (44%), and loss of libido (26%). Physician instructions to patients included treatment with phlebotomy (90%), testing family members (75%), and avoiding iron supplements (65%). CONCLUSIONS: The diagnosis of hemochromatosis in most patients was delayed. Physician education is needed to increase the detection of patients with the disease and to improve its management.

Adolescent↗

PubMed1999

World Health Organization hemoglobin cut-off points for the detection of anemia are valid for an Indonesian population.

The study was designed to determine whether population-specific hemoglobin cut-off values for detection of iron deficiency are needed for Indonesia by comparing the hemoglobin distribution of healthy young Indonesians with that of an American population. This was a cross-sectional study in 203 males and 170 females recruited through a convenience sampling procedure. Hemoglobin, iron biochemistry tests and key infection indicators that can influence iron metabolism were analyzed. The hemoglobin distributions, based on individuals without evidence of clear iron deficiency and infectious process, were compared with the National Health and Nutrition Survey (NHANES) II population of the United States. Twenty percent of the Indonesian females had iron deficiency, but no male subjects were iron deficient. The mean hemoglobin of Indonesian males was similar to the American reference population at 152 g/L with comparable hemoglobin distribution. The mean hemoglobin of the Indonesian females was 2 g/L lower than that of the American reference population, which may be the result of incomplete exclusion of subjects with milder form of iron deficiency. When the WHO cutoff (Hb < 120 g/L) was applied to female subjects, the sensitivity of 34.2% and specificity of 89.4% were more comparable to the test performance for white American women, in contrast to those of the lower cut-off. On the basis of the finding of hemoglobin distribution of men and the test performance of anemia (Hb < 120 g/L) for detecting iron deficiency for women, it is concluded that there is no need to develop different cut-off points for anemia as a tool for iron-deficiency screening in this population.

Adolescent↗

PubMed1998

Development of a research child growth reference and its comparison with the current international growth reference.

OBJECTIVE: To better characterize childhood growth and further assess potential limitations of the current National Center for Health Statistics and World Health Organization international growth reference. DESIGN: The LMS method was used for curve fitting to summarize the changes in height and weight distributions by 3 curves representing the skewness (L), median (M), and coefficient of variation (S). A series of polynomial regression procedures was applied to smooth the L, M, and S curves. SETTING: Subset data from 18 states contributing clinic data to the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System were used for this research reference. METHODS: We chose only those clinics in which the height and weight distributions of children closely matched with those of the first and second National Health and Nutrition Examination Surveys. RESULTS: Unlike the current international growth reference, the new reference has no disjunction at 24 months of age because it is based on a single data source for children aged 0 to 59 months. The reference also better characterizes the growth for infants than the current international reference, a fact we demonstrated with data from the National Health and Nutrition Examination Surveys, Pediatric Nutrition Surveillance System 1995, and the Davis Area Research on Lactation, Infant Nutrition, and Growth studies. CONCLUSIONS: The current National Center for Health Statistics and World Health Organization international growth reference needs to be updated. The methods used in this study will be useful to evaluate other data sets and to evaluate future modifications of growth references.

Body Height↗

PubMed1998

Reappraisal of the role of vegetables in the vitamin A status of mothers in Central Java, Indonesia.

Food-based approaches for controlling vitamin A deficiency and its consequences, such as increased mortality, more severe morbidity, and anemia, have become increasingly important, thus prompting a reassessment of the relation between vitamin A intake and status. A nutrition surveillance system in Central Java, Indonesia, assessed the vitamin A intake and serum retinol concentration of women with a child < or =24 mo old with a semiquantitative 24-h recall method that categorized vitamin A-containing foods into 3 categories of plant foods and into 2 categories of animal foods and identified portions as small, medium, or large. Median vitamin A intake was 335 retinol equivalents (RE)/d (n = 600) and vitamin A intake from plant foods was 8 times higher than from animal foods. Serum retinol concentration was related to vitamin A intake in a dose-response manner. The multiple logistic regression model for predicting the chance for a serum retinol concentration greater than the observed median (> or = 1.37 micromol/L) included physiologic factors, vitamin A intake from plant [odds ratio (95% CI) per quartile: 1st, 1.00: 2nd, 1.23 (0.75, 2.02); 3rd, 1.60 (0.97, 2.63); and 4th, 2.06 (1.25, 3.40)] and animal [1st and 2nd, 1.00; 3rd, 1.31 (0.86, 2.02); and 4th, 2.18 (1.40. 3.42)] foods, home gardening [(no, 1.00; yes, 1.71 (1.12, 2.60)], and woman's education level [< or =primary school, 1.00; > or =secondary school, 1.51 (1.02, 2.22)]. Despite the fact that plant foods contributed 8 times as much vitamin A as did animal foods, serum retinol concentrations did not reflect this large difference. Home gardening and woman's education level seemed to reflect longer-term consumption of vitamin A-rich plant and animal foods, respectively.

Adult↗

PubMed1998

The NCHS reference and the growth of breast- and bottle-fed infants.

The current international growth reference, the National Center for Health Statistics (NCHS) reference, is widely used to compare the nutritional status of populations and to assess the growth of individual children throughout the world. Recently, concerns were raised regarding the adequacy of this reference for assessing the growth of breast-fed infants. We used the NCHS reference to evaluate infant growth in one of the most developed areas of Brazil. Infants who were exclusively or predominantly breast-fed for the first 4-6 mo, and partially breast-fed thereafter, grew more rapidly than the NCHS reference in weight and length during the first 3 mo, but appeared to falter thereafter. The average growth of all infants, regardless of feeding pattern, was faster than the NCHS reference until approximately 6 mo, after which their growth became slower than that of the NCHS sample. To substantiate this finding, the NCHS growth curves were then compared with growth data of breast-fed infants in developed countries from pooled published studies, formula-fed North American and European infants and predominantly bottle-fed U.S. infants monitored by the Centers for Disease Control and Prevention (CDC) Pediatric Surveillance System. In all three cases, weights showed the same pattern as the Brazilian infants-higher than NCHS in the early months but an apparent decline thereafter. The pattern for length gain was similar but less marked. Breast-fed infants showed more pronounced declines than those who were predominantly bottle-fed. These findings suggest that the infancy portion of the NCHS reference does not adequately reflect the growth of either breast-fed or artificially fed infants. This probably results from characteristics of the original sample and from inadequate curve-fitting procedures. The development of an improved international growth reference that reflects the normal infant growth pattern is indicated.

Body Height↗

PubMed1998

Increasing prevalence of overweight among US low-income preschool children: the Centers for Disease Control and Prevention pediatric nutrition surveillance, 1983 to 1995.

OBJECTIVE: To determine whether the prevalence of overweight in preschool children has increased among the US low-income population. DESIGN: Analysis using weight-for-height percentiles of surveillance data adjusted for age, sex, and race or ethnicity. SETTING: Data from 18 states and the District of Columbia were examined. SUBJECTS: Low-income children <5 years of age who were included in the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System. RESULTS: The prevalence of overweight increased from 18.6% in 1983 to 21.6% in 1995 based on the 85th percentile cutoff point for weight-for-height, and from 8.5% to 10.2% for the same period based on the 95th percentile cutoff point. Analyses by single age, sex, and race or ethnic group (non-Hispanic white, non-Hispanic black, and Hispanic) all showed increases in the prevalence of overweight, although changes are greatest for older preschool children. CONCLUSION: Overweight is an increasing public health problem among preschool children in the US low-income population. Additional research is needed to explore the cause of the trend observed and to find effective strategies for overweight prevention beginning in the preschool years.

Body Height↗

PubMed1998

[The development of reference values for the brachial perimeter and body height in comparison with other indicators used for screening of the nutritional status].

Mid-upper-arm circumference (MUAC) based on a single cut-off value for all children under 5 years of age has been used for many years as an alternative nutritional status index for children during famines or refugee crises, and as an additional screening tool in nonemergencies. However, it has recently been questioned whether MUAC is age- and sex-independent. After reviewing the scientific evidence underlying the use and interpretation of MUAC, a WHO Expert Committee recommended a new MUAC-for-age reference for under-5-year-olds. In some settings, however, it is difficult to assess a child's age and in such circumstances MUAC-for height may be a good alternative. The height-based QUAC stick offers a simple means of adjusting MUAC cut-offs according to height, and the MUAC-for-height reference and construction and use of the QUAC stick are described in this article. Also described is the use of the receiver operating characteristic (ROC) curve method to evaluate the performance of MUAC, MUAC-for-age, and MUAC-for-height in screening malnourished children.

Arm↗