Effects of static compression with different loading magnitudes and durations on the intervertebral disc: an in vivo rat-tail study

STUDY DESIGN

An in vivo rat-tail model was used to study the effects of static compression with different loading magnitudes and durations on the intervertebral disc.

OBJECTIVE

To investigate the effects of static compression with different loading magnitudes and durations on the intervertebral disc over a period of time.

SUMMARY OF BACKGROUND DATA

A disc degeneration model is essential for studying therapeutic effects on degenerated disc. Static compression can induce degenerative-like changes in the intervertebral disc. However, the consequences of the simulation model over a period of resting have not been clearly documented, which may have confounding effects on the experimental outcome.

METHODS

Thirty-five rats were used. Static compressions with different loads (11 or 17 N) and durations (1 hour daily or continuous) were applied to the rat-tail caudal 8-9 disc for 2 weeks, and followed with 3 weeks of rest. The disc height was quantified in vivo on days 4, 18, and 39. The rats were killed and the discs were harvested for morphologic examination on day 39 after the disc height measurement.

RESULTS

Significant decrease in disc height was observed after continuous static compression for both 11 and 17 N, and continued during the resting period. The morphologic evaluation of the continuous compressed disc showed a decreased nuclear size, reduced number of nuclear cells, and irregular nuclear shape with inward bulging of disorganized annular collagen lamellas. Daily compression of 1 hour was found to induce a transient increase in disc height, but restored after the 3-week resting period. Favorable morphologic changes, including vacuolated nuclear cells and oval nuclear shape with well-organized annular collagen lamellas, were seen in the rat disc specimens with daily compression of 1 hour.

CONCLUSION

Disc degenerative-like changes without recovery were demonstrated in the rat caudal disc after continuous compression. The changes in disc height and disc morphology were found to be dependent on the duration of load application and may have clinical implication.

Interactions of mRNAs and gRNAs involved in trypanosome mitochondrial RNA editing: structure probing of an mRNA bound to its cognate gRNA

Posttranscriptional editing of trypanosome mitochondrial messenger RNA is directed by small guide RNAs (gRNAs). Using crosslinking techniques, we have previously shown that the gRNA base pairs to the mRNA via a 5' anchor, whereas its 3' U-tail interacts with upstream purine-rich mRNA sequences. The incorporation of crosslinking data into RNA folding programs produced similar structure predictions for all gRNA/mRNA pairs examined. This suggests that gRNA/mRNA pairs can form common secondary structure motifs that may be important for recognition by the editing complex. In this study, the structure of CYb mRNA crosslinked to gCYb-558 was examined using solution-probing techniques. The mRNA/gRNA crosslinked molecules are efficient substrates for gRNA-directed cleavage. In addition, when the cleavage assay is performed in the presence or absence of additional UTP, the activities of both the U-specific exonuclease and terminal uridylyl transferase (tutase) can be detected. These results indicate that a partial editing complex can assemble and function on these substrates suggesting that the crosslink captured the molecules in a biologically relevant interaction. The structure probing data directly show that the U-tail protects several mRNA bases predicted to be involved in the U-tail-mRNA duplex. In combination with our previous studies, these new data provide additional support for the predicted secondary structure of interacting gRNA/mRNA pairs.

Association between simple anthropometric indices and cardiovascular risk factors

OBJECTIVE

To identify which of the three simple anthropometric indices, body mass index (BMI), waist-to-hip ratio (WHR) and waist circumference (WC), best predicts cardiovascular risk factors, and to determine if the association between the anthropometric indices and cardiovascular risk factors varies with gender.

DESIGN AND METHODOLOGY

A cross-sectional population-based survey was carried out during 1995-1996. One thousand and ten Chinese people (500 men and 510 women) aged 25-74 y were recruited as subjects for the study. Metabolic profiles and anthropometric indices were measured.

RESULTS

Partial correlation and co-variance analyses showed that WC exhibited the highest degree of association with almost all of the studied metabolic profiles for both men and women. We observed significant gender differences in the association between central or general obesity with cardiovascular risk factors. BMI had an independent and significant association with metabolic risks in men, but not in women, whereas WHR was more strongly correlated with metabolic risks for women than for men. Logistic regression analysis further confirmed the magnitude of the association between the obesity indices and metabolic risks. Among the studied metabolic variables, serum insulin showed the highest degree of association with the obesity indices, followed by plasma glucose, triglyceride, HDL and blood pressure. Total cholesterol and LDL-cholesterol had a small but significant correlation with obesity. No threshold values in the relation between either the anthropometric indices and metabolic values, or with hypertension, diabetes and dislipidemia were observed.

CONCLUSION

The association of central or general obesity and metabolic syndrome varied with gender. In addition, the useful anthropometric predictors for cardiovascular risk factors were BMI and WC for men, and WC and WHR for women.

Dietary habit of smokers in a Chinese population

The objective of this study is to determine whether smokers have unhealthy dietary habits with respect to cardiovascular diseases and cancer. An age and sex stratified random sample of the Hong Kong Chinese population aged 25 to 74 years (500 men, 510 women) was recruited. A dietary assessment using a food frequency method over a 7 day period, together with a lifestyle questionnaire was administered by a trained interviewer. Approximately half the men were smokers, while only 19/510 women smoked. Smoking was related to lower education level. Male smokers had a lower mean daily consumption of fruits, lower carbohydrate and carbohydrate percentage calorie intake, higher fat and fat percentage calorie intake, and higher vitamin D intake compared with non-smokers. However, the differences were small compared with reported differences in Caucasian populations. No difference in dietary pattern was noted between female smokers and non-smokers. Although there is a tendency for male smokers to have an unhealthy dietary pattern with respect to cardiovascular disease and cancer, the differences between smokers and non-smokers are small, and together with the favourable health features of the Chinese diet, this difference is unlikely to add to the risk of these diseases in smokers or be a confounding factor in examining the aetiology of smoke-related diseases in this population.

Aquatic reclamation in the Athabasca, Canada, oil sands: naphthenate and salt effects on phytoplankton communities

Microcosm experiments with natural indigenous phytoplankton communities were conducted to assess the effects of waters from oil sands extraction processes, emphasizing the naphthenate and salt constituents. Process waters of varying ages (zero to eight years) remediation histories, and chemical composition were obtained from outdoor mesocosms and inoculated with phytoplankton assemblages from a reference lake in the study area. Community composition measures, including percentage model affinity (PMA) and canonical correspondence analysis (CCA), revealed significant community effects of water from systems less than five years old, with naphthenate concentrations greater than 20 mg/L, compared to water from the reference lake. Canonical correspondence analysis, PMA, and regression analyses further showed that naphthenate concentration was significantly correlated with community structure. Using CCA, groups of taxa characteristic of waters with > 20 mg/L naphthenates (including Botryococcus braunii, Gloeococcus schroeteri, Cosmarium depressum, Chrysococcus rufescens, Chromulina spp., Ochromonas spp., and Keratococcus spp.) were identified. Salinity, as reflected in conductivity, was positively correlated with naphthenate concentration and itself appeared to influence the community structure. The results confirmed an important role for naphthenates in ecological effects of process waters from oil sands mining, but the influence of covarying factors such as salinity requires further investigation.

Postnatal iron status of Hong Kong Chinese women in a longitudinal study of maternal nutrition

OBJECTIVE

To report postnatal iron nutritional status of Hong Kong Chinese women during the first 6 months postpartum.

DESIGN AND SUBJECTS

A longitudinal study examining postnatal calcium and iron status of Hong Kong Chinese breastfeeding and formula-feeding women was conducted during 1998. Postpartum women aged 20-40 y, with no bone or blood disorders were recruited and interviewed at 0 (baseline), 2, 6 weeks, 3 and 6 months postpartum. Dietary intake was assessed by a 3 day dietary record and cross checked by a 24 h recall. Complete blood count and serum ferritin level were measured to assess anaemia and iron status. In this report, subjects were divided into an anaemic group (haemoglobin level < 10 g/dl) and a non-anaemic group (haemoglobin level > or = 10 g/dl) according to baseline haemoglobin levels.

RESULTS

At baseline, 13/47 (27.7%) subjects were anaemic. Two of these 13 anaemic subjects were still anaemic at 3 and 6 months postpartum. Anaemic subjects showed significantly (P < 0.01) greater amounts of blood loss and a higher rate of primary postpartum haemorrhage than the non-anaemic subjects. Daily food intake and dietary nutrient intake did not differ significantly between the two groups. During the first 6 weeks postpartum, subjects in both groups consumed more poultry and egg, and comparable amounts of meat, compared with women in the Hong Kong general population. Iron and vitamin C intakes for the majority of subjects reached 60% of the US Recommended Daily Allowances. Regression analysis suggested that the rate of change in haemoglobin level in the first 6 weeks postpartum was positively correlated with baseline MCV level and serum ferritin level, but negatively correlated with baseline haemoglobin level.

CONCLUSIONS

Blood loss at delivery is an important factor for postpartum anaemia. Postnatal recovery of iron status of this group of women appeared to be more related to physiological factors than to dietary factors. The role of diet as well as other physiological changes in postpartum women requires further investigation. Finding ways to minimise blood loss at delivery could be the most practical strategy to reduce the rate of postpartum anaemia.

SPONSORSHIP

CSM was supported by a research studentship from the Research Grants Council, Hong Kong.

Differential impacts of coping strategies on trati the mental health of Chinese nurses in hospitals in Hong Kong

This study examined the types of coping strategies used by hospital nurses in Hong Kong. The impacts of these coping strategies on the mental health of nurses were also investigated. Results showed that coping strategies were both situation-specific and culture-specific, with direct action coping, acceptance and positive thinking used more frequently than avoidance and alcohol. It was found that more than one-third of the nurses were considered to be at risk of developing poor mental health, and the most frequent symptomatic complaints included anxieties and feelings of inadequacy in handling daily activities. Nurses who were mentally healthy used more direct action coping and positive thinking, and fewer avoidance strategies and drinking than did nurses who were at risk of developing poor mental health. Contrary to our hypothesis, nurses who adopted more acceptance strategies had poorer mental health. Implications of the study are discussed.

Growth and nutrition of Chinese vegetarian children in Hong Kong

OBJECTIVE

The study investigated the nutritional status of Chinese lacto-ovo-vegetarian children aged 4-14 years.

METHODOLOGY

Dietary intake over 7 days was assessed using a computer program, previously used for a local population-based dietary survey. Anthropometric measurements were made and fasting venous blood was examined for serum lipids, haematological data, iron, vitamin B12 and folate status. Bone mineral density (BMD) of the spine (L2 - L4) was measured as a reflection of calcium status.

RESULTS

Fifty-one lacto-ovo-vegetarians aged 4-14 years were investigated. The mean +/- standard deviation (SD) daily energy intake was 1600 +/- 425 kcal. The mean (+/- SD) daily protein intake was 1.6 +/- 0.6 g/kg bodyweight which met the United States recommended dietary allowance. Compared to that of the local omnivore diet, the vegetarian diet was closer to the recommended healthy diet with lower fat (20-23%), more fibre (5.8-8.7 g/day) and better polyunsaturated to saturated fatty acid ratio (1.0-1.1). Growth and BMD of the vegetarian children were comparable to the general omnivore population. Two children had iron deficiency and two children had anaemia. The calcium status, as reflected by the BMD, was not impaired. Serum folate and vitamin B12 were within the normal range. Six (25%) boys and four (15%) girls were obese. Three boys had hyperlipidaemia.

CONCLUSIONS

A Hong Kong Chinese vegetarian diet appears healthy, providing adequate iron and vitamin B12 nutrition, but the prevalence of obesity was high.

Ikirara insertions reveal five new Anopheles gambiae transposable elements in islands of repetitious sequence

Characterization of Anopheles gambiae genomic clones containing Ikirara inverted repeats revealed five novel sequences related to known transposable elements (TEs). One TE is related to the mariner/Tc1 superfamily of class II (DNA-to-DNA) transposons, while four are related to class I (RNA-mediated transposition) elements. Crusoe, the class II element; is most similar to the Caenorhabditis elegans transposon Tc1-like TEs. Vash elements, represented twice in our clones, are related to the Q/T1 family of A. gambiae non-LTR retrotransposable elements. Guildenstern is a member of the RT1 and RT2 non-LTR retrotransposon family. Although RT1 and RT2 elements normally have a highly stereotyped insertion preference for sequences within ribosomal genes, Guildenstern is not located in ribosomal sequence. JuanAg is the first anopheline member of the mosquito non-LTR retrotransposon family of Juan elements that previously had included just the culicine elements JuanA and JuanC. Approximately 753 bp is missing from the central portion of the JuanAg reverse transcriptase gene, where an Ikirara inverted repeat is found in its stead. Ozymandias, the only LTR retrotransposon found in the clones, is most similar to the Drosophila melanogaster 412 element. Single Ikirara inverted repeats were also found adjacent to nontransposable element repetitious sequences. Our analysis suggests that the A. gambiae genome organization could best be described as islands of short-period interspersion repetitious DNA in a sea of long-period interspersion, mostly unique sequence DNA.

The Mediterranean score of dietary habits in Chinese populations in four different geographical areas

OBJECTIVE

To compare the dietary intake of Chinese people living in Pan Yu, Hong Kong, San Francisco and Sydney with respect to cardiovascular health, using the Mediterranean diet score, examining the effects of age, gender, urbanization and acculturation on the diet score.

SUBJECTS

A total of 500 men and 510 women in Hong Kong were recruited as a territory-wide stratified random sample. Subjects were recruited in response to local advertisements for the other three sites: Pan Yu, 58 men, 95 women; San Francisco, 166 men, 192 women; Sydney, 95 men, 73 women.

METHOD

Food-frequency questionnaire over a 7 week period. A high/healthy score was taken as > or =4 for men and >3 for women, representing a dietary pattern beneficial for cardiovascular health.

RESULTS

In Hong Kong, more women in the middle age group (35-54) had a high score than other age groups, and overall more women had high scores than men. In comparing the four geographical regions, Pan Yu had the highest number of subjects with high score, and Hong Kong had the lowest. With the exception of the younger population and men in Hong Kong, the percentage of the population with a high score in all sites is greater than among elderly Greeks consuming a more traditional heart-healthy Mediterranean diet.

CONCLUSION

Considerable variations in Chinese dietary patterns exist with respect to age, gender and geographic location. Overall, the Chinese diet is comparable to the Mediterranean diet and may be expected to have similar health benefits that have been documented for the traditional Mediterranean diet.

RNA editing in Trypanosoma brucei: characterization of gRNA U-tail interactions with partially edited mRNA substrates

Guide RNAs (gRNAs), key components of the RNA editing reaction in Trypanosoma brucei, direct the insertion and deletion of uridylate (U) residues. Analyses of gRNAs reveal three functional elements. The 5'-end of the gRNA contains the anchor, which is responsible for selection and binding to the pre-edited mRNA. The second element (the guiding region) provides the information required for editing. At the 3'-end of the gRNA is a non-encoded U-tail, whose function remains unclear. However, the cleavage-ligation model for editing proposes that the U-tail binds to purine-rich regions upstream of editing sites, thereby strengthening the interaction and holding onto the 5' cleavage product. Our previous studies demonstrated that the U-tail interacts with upstream sequences and may play roles in both stabilization and tethering. These studies also indicated that the U-tail interactions involved mRNA regions that were to be subsequently edited. This raised the question of what happens to the mRNA-U-tail interaction as editing proceeds in the 3'-->5' direction. We examined gCYb-558 and its U-tail interaction with 5'CYbUT and two partially edited 5'CYb substrates. Our results indicate that the 3'-end of the U-tail interacts with the same sequence in all three mRNAs. Predicted secondary structures using crosslinking data suggest that a similar structure is maintained as editing proceeds. These results indicate that the role of the U-tail may also involve maintenance of important secondary structure motifs.

Sodium is the leading dietary factor associated with urinary calcium excretion in Hong Kong Chinese adults

We conducted a cross-sectional population-based study comprising 1010 Hong Kong Chinese (500 men and 510 women) aged 25-74 years during 1995-6. The study examined the important dietary, lifestyle and anthropometric factors associated with urinary calcium excretion. Dietary intakes were assessed by means of food frequency questionnaire. Spot urine was collected to measure the urinary excretion profiles of calcium (Ca), sodium (Na), potassium (K) and creatinine (Cr). When expressed as ratios of cations to urinary Cr, significant relationships were noted between urinary Ca and Na (r: approximately 0.6), and between urinary Ca and K (r: 0.17-0.21). Stepwise multiple linear regression analyses were carried out separately in men and women aged below and above 50 years. We found that urinary Na/Cr was the leading independent factor associated with urinary Ca/Cr in all four age and sex groups. It accounted for 22% of urinary Ca/Cr variations in women aged below 50 years, and 35-43% in the other three age and sex groups. We estimated that urinary Ca excretion increased by about 1.4 (range 1.37-1.43) mmol per 100 mmol increase in urinary Na. Except in men aged 50 years and over, urinary K/Cr was inversely associated with urinary Ca/Cr in all groups. Age was independently and positively associated with urinary Ca/ Cr in subjects aged below 50 years. We did not observe any significant relation between urinary Ca/Cr and dietary protein, phosphorus, alcohol drinking and smoking. In conclusion, we found that urinary Na/Cr, but not dietary protein, Ca or phosphorus, is the most important factor influencing urinary Ca/Cr excretion in our population. Urinary K is a potential factor for Ca conservation.

Studies on common illnesses and medical care utilization patterns of adolescents in Hong Kong

PURPOSE

To estimate the prevalences of common illnesses in Hong Kong adolescents, the sociodemographic and selected risk factors associated with these illnesses, and their health care utilization behavior and attitudes.

METHODS

A cross-sectional questionnaire survey of 3355 participating secondary school students (response rate = 98%).

RESULTS

Self-reported 3-month prevalences were obtained for cough/cold/influenza (55.2%), digestive disorders (34.6%), accidental injuries (29.5%), headache/dizziness (23.6%), chronic anxiety/insomnia (20.1%), skin problems (9.5%), asthma (3.8%), liver disease (1.3%), and menstrual pain (13.8% of female students). Self-perceived poor health, smoking, and alcohol consumption were associated with many of these illnesses. Treatment choice depended on the illness suffered (e.g., most students with respiratory problems consulted medical practitioners, whereas most with chronic anxiety/insomnia did not). Many students lacked trust in their doctors, doctor-shopped, relied heavily on self-medication, did not comply with prescribed treatments, would not seek help about medical problems, felt they had insufficient access to health information, and wanted confidential health care.

CONCLUSIONS

This study examined for the first time the common illnesses and health care utilization patterns of Hong Kong adolescents. Students with chronic anxiety/insomnia were much less likely to seek care, indicating a need for better education on mental health. Efforts to prevent smoking and alcohol consumption among adolescents need to be strengthened. The students' attitudes, poor compliance and help-seeking behaviors suggest suboptimal use of the health care system. Our findings are useful for international comparisons by medical practitioners, health care managers, and researchers.

Fat intake in Hong Kong Chinese children

The people of Hong Kong are experiencing a transition in dietary practices and lifestyle that can be observed in the fat intakes of Hong Kong children as compared with those of their counterparts on mainland China. The studies described here include 1) a longitudinal and observational dietary survey beginning with a cohort of 174 newborns and concluding with 124 children at age 7 y; 2) a biochemical study of serum lipids in relation to dietary fat intake at age 7 y; 3) a chemical fatty acid analysis and comparison of duplicate meals collected from 20 Hong Kong and 20 mainland Chinese children at age 7 y; 4) a dietary assessment of 52 lactoovovegetarian children aged 4-14 y; and 5) a comparison of the growth of all subjects with US National Center for Health Statistics standards. About 30% of the total daily energy intake of Hong Kong Chinese children aged 1-7 y was contributed by fat-much more than that in the traditional Chinese diet. Growth of the children was not impaired, including that of children on the mainland and of those lactoovovegetarians in Hong Kong whose fat intakes were lower. Mean serum cholesterol of Hong Kong Chinese children at age 7 y was 4.59 mmol/L, significantly higher than that of their counterparts on the mainland, 4.16 mmol/L. Foods consumed in Hong Kong had a significantly lower ratio of 18:2 to 14:0. Nutritional deficiency was uncommon. Chinese children in Hong Kong had a dietary fat intake that was both quantitatively and qualitatively different from the traditional Chinese diet.

Special postpartum dietary practices of Hong Kong Chinese women

OBJECTIVE

A 'ginger vinegar soup' and other special dietary practices have been traditionally recommended for postpartum Chinese women. This paper describes these practices in the first 6 weeks postpartum, and details of the calcium and iron content of the 'ginger vinegar soup'.

DESIGN AND SUBJECTS

Results of this paper were generated from a longitudinal study on the nutritional status of Hong Kong Chinese postpartum women. 'Ginger vinegar soup' samples were collected at the 2 week home visits. Calcium and iron content were measured by the combination of dry ashing method and atomic absorption spectrophotometry. Results were compared with other types of soup and food sources. A food frequency questionnaire was completed at the 6 week interview to assess the special dietary practices during this period.

RESULTS

Fifty-one subjects completed the food frequency questionnaires. Twenty-two ginger vinegar soup samples and six other soup samples were collected. Consumption of special food items such as ginger, pig's trotters, egg and chicken varied greatly among subjects. More poultry and similar amounts of egg were consumed by our subjects as compared with the Hong Kong general population. Chicken soup and ginger vinegar soup were commonly consumed. Median calcium and iron contents of the ginger vinegar soup were 4.65 and 0.84 mg/dl, respectively. This calcium content was higher than that of the other six soup samples, but was low as compared with other calcium-rich foods. Iron content of ginger vinegar soup was higher than that of the other six samples and was comparable to some iron-rich foods.

CONCLUSIONS

Hong Kong Chinese postpartum women followed traditional dietary practices to different degrees. These practices were characterized by an increased poultry consumption. Iron content of ginger vinegar soup was comparable to some iron-rich foods.

Breastfeeding failure in a longitudinal post-partum maternal nutrition study in Hong Kong

OBJECTIVE

To describe factors associated with breastfeeding failure during the first 6 months post-partum in a sample of Hong Kong Chinese women participating in a longitudinal study of maternal nutrition.

METHODOLOGY

Forty-four Hong Kong Chinese lactating mothers who intended to breastfeed exclusively for at least 3 months were recruited and followed for 6 months post-partum. Demographic data were compared with 20 mothers who intended to use formula feeding. Mothers were followed up at 2 and 6 weeks and 3 and 6 months and details of infant feeding practices were obtained. Information was sought on breastfeeding management in hospital, reasons for discontinuation of breastfeeding or for providing supplements to babies and intention to seek, and sources of, lactation support.

RESULTS

Thirty-nine mothers who planned to breastfeed completed the follow up. Compared with mothers in the formula-feeding group, breastfeeding mothers were more likely to be professionals or housewives. Continuation of any breastfeeding (total and partial) was noted in 30 (77%), 22 (57%), 16 (41%) and 12 (31%) mothers at 2 and 6 weeks and 3 and 6 months post-partum, respectively. The majority (97%) of mothers stated that they were given information on the benefits and management of breastfeeding. However, late initiation of breastfeeding and providing supplements to babies were common. Perceptions of insufficient milk supply (44%), breast problems (31%) and being too tired (28%) were the main reasons stated for stopping breastfeeding or for providing supplements to babies. Midwives from the postnatal wards and hotlines were the main sources of lactation support.

CONCLUSIONS

These results highlight difficulties in sustaining breastfeeding, either exclusive or partial, in Hong Kong Chinese women. Despite being recruited on the basis of intending to exclusively breastfeed for 3 months, less than half these mothers were still breastfeeding and only approximately one-third were exclusively or predominantly breastfeeding at 3 months. More needs to be done within the hospital environment to initiate breastfeeding immediately after birth and to avoid giving unnecessary supplements and more effort is needed to foster a mother's confidence, commitment and knowledge of breastfeeding.

Intake of soy products is associated with better plasma lipid profiles in the Hong Kong Chinese population

We describe the pattern of soy intake and its association with blood lipid concentrations in the Hong Kong Chinese population. Subjects were contacted by random telephone survey and invited to a hospital for a physical examination and blood tests. A total of 500 men and 510 women with an age range of 24-74 y completed the dietary intake study. The dietary assessment was based on a semiquantitative food frequency questionnaire that included 10 commonly consumed soy items. Many (88%) of the study population had consumed some soy products during the previous week. About 80% of the soy protein or isoflavones were obtained from different forms of tofu, and an additional 9% was obtained from soy milk. The mean weekly isoflavone intake was 102 +/- 107 mg in men and 77 +/- 90 mg in women. In men, soy intake and total plasma cholesterol were negatively correlated (r = -0.09, P: = 0.04), as were soy intake and LDL cholesterol (r = -0.11, P: = 0.02). The respective values in women <50 y old were r = -0.11, P: = 0.04 and r = -0.11, P: = 0.05. Soy protein remained significantly associated with these two lipid concentrations after adjustment for other social and dietary confounders. Higher soy intake seemed to be related to a better plasma lipid profile in men and in younger women, but more epidemiological studies and controlled clinical trials in this setting would help to confirm the optimal amount required for the prevention and treatment of hyperlipidemia.

Dietary fibre intake and constipation in children with severe developmental disabilities

OBJECTIVE

Constipation is a common problem in children with severe developmental disabilities (DD). This study aimed to evaluate fibre intake of severe DD children living in a residential institution, and the possibility of reducing the use of laxatives by increasing their fibre intake.

METHODOLOGY

A baseline study was performed to evaluate the fibre and macronutrient intake in a group of severe DD children. Nutrients including fibre for a standard serving in each meal were calculated and daily macronutrients and fibre intake were estimated. An intervention study was then carried out to evaluate whether increasing fibre intake could relieve constipation. A total of 20 children aged between 3 and 17 years were assessed over a 4-month period. In a residential unit for severe DD children, laxatives were routinely prescribed if there was no spontaneous bowel motion for two consecutive days. Fibre intake was increased in stages by adding All-Bran(R) (Kellogg Company, Battle Creek, MI, USA) and desserts. The mean number of laxative usage per week per child in the different stages were then compared.

RESULTS

The baseline fibre intake was found to be approximately 2 g/day. The mean number of laxatives required per week per child decreased significantly from a baseline value of 1.22 (about 5 laxatives/month) (standard deviation (SD) = 0.36)) to 0.90 (about 3. 5 laxatives/month) (SD = 0.75) in the first stage, and 0.71 (about 3 laxatives/month) (SD = 0.40) in the second stage. Using paired t-test, the difference was statistically significant when compared with the baseline: P < 0.05 for the first, and P < 0.01 for the second stage of fibre supplementation.

CONCLUSION

Very low daily intake of fibre of 2 g/day was documented. Relief of constipation and a significant reduction in the usage of laxatives was demonstrated by increasing fibre intake to 17 g/day (stage 1). Increasing fibre intake further to 21 g/day (stage 2), showed a further reduction in the use of laxatives. There was, however, no statistical significance between stage 1 and stage 2 of fibre supplementation. Alternative ways to further relieve constipation in severe DD children require further studies.

Streamlined synthesis of substituted 2-aminothiazoles using tandem precipitative and polymer-assisted reactions

The tactical combination of classical product precipitation and subsequent modification of precipitated products using polymer-assisted transformations has been employed in the preparation of substituted 2-aminothiazole derivatives. 2-aminothiazoles were precipitated in parallel as hydrobromide monohydrate salts, directly redissolved, and reacted further using polymer-supported reagents to afford free-based 2-aminothiazoles, aminothiazoyloxamates, and aminothiazoylamides.

Growth and nutrition of Hong Kong children aged 0-7 years

OBJECTIVE

To study the early dietary practices in relation to growth of Hong Kong children from birth to 7 years.

METHODOLOGY

One hundred and seventy-three full-term Hong Kong Chinese babies were recruited at birth and were followed up for anthropometric measurements using standardized methods and dietary assessment using a combination of dietary history, 24 h recall and food frequency. At 7 years, 125 children remained in the study.

RESULTS

Mean (SD) birthweight was 3.3 (0.38) kg for boys and 3.1 (0.38) kg for girls. Mean (SD) weight at 7 years was 22.4 (4.2) kg for boys and 21.1 (3.7) kg for girls, and mean (SD) height was 120.3 (4.8) cm for boys and 119.8 (5.1) cm for girls. Hong Kong children were lighter and shorter than Australian children and the National Centre for Health Statistics (NCHS) references, but the magnitude is less than one standard deviation score. Mean weight and height of Hong Kong children were lower compared to Caucasian and Beijing children, with more obvious differences between 1 and 5 years. At 1 year, mean (SD) daily energy intake was 98 (24) kcal/kg/day for boys and 100 (26) kcal/kg/day for girls. By 7 years, it decreased to 82 (18) kcal/kg/day for boys and 73 (22) kcal/kg/day for girls. Between 2 to 4 years of age the energy intake of studied children were slightly lower than the Australian and Finnish children, but the protein intake was higher. Percentage of fat contributing to total daily energy intake was lower throughout at a level of 30%. Such differences in diet reflect a lower consumption of milk fat, higher consumption of meat and lower level of physical activity in Hong Kong children. Intakes of calcium, iron and vitamin C all reached 60% or above of US recommended daily allowance.

CONCLUSIONS

The smaller body build of Chinese compared to Caucasians cannot be explained by dietary differences. The diet of Hong Kong children is changing to one which is more Westernized with a higher consumption of animal products.

Height and weight percentile curves of Beijing children and adolescents 0-18 years, 1995

Nationwide growth survey has been performed once every 10 years in Mainland China since 1975. However, no percentile growth curves for children from birth to 18 years have ever been constructed for clinical use. The third survey was performed in 1995 and from this survey, data of the Beijing population were retrieved to construct the height for age and weight for age percentile curves. A total of 12218 healthy children were examined for height and weight, using the standardized methods. Height, but not weight, was normally distributed. Smoothing was performed separately for each sex, using JPA2 model for mean height for age > 2 years. Otherwise, smoothing was performed for the following curves by polynomial equations up to the order of the 5th degree for height and 12th degree for weight, mean height for age < 2 years, SD curve of height for age from birth to 18 years, median weight for age < 2 years, median weight for age > 2 years, differences between the 3rd, 10th, 25th, 75th, 90th, 97th centiles and the median for age from birth to 18 years. The predicted adult height was 173.43cm for boys and 160.86 cm for girls, with age of peak velocity at 13 years and 11.5 years for boys and girls respectively. Compared to those in Hong Kong, they were 2.3-2.5 cm taller signifying a geographical difference in growth even within one country. Compared to the Beijing data collected in 1975 and 1985 the secular changes in growth were more obvious in the first decade, suggesting that the Beijing population was approaching the optimal adult height.

Role of aggregates in Claisen acylation reactions of imidazole, pyrazole, and thioesters with lithium enolates in THF

[formula: see text] Although phenyl esters react with both monomers and dimers or tetramers of two lithium enolates in THF, the reactions of phenyl thiobenzoates are relatively much faster with the monomers. Similarly, imidazole esters react primarily with the monomers but pyrazole esters react with monomers and aggregates. The results are rationalized by a mechanism in which coordination with two lithium cations within an enolate aggregate is required for the reaction of aggregates to compete with monomers.

Influence of educational level and marital status on dietary intake, obesity and other cardiovascular risk factors in a Hong Kong Chinese population

OBJECTIVES

To examine the influence of education and marital status on dietary intake, body mass index, waist hip ratio, blood pressure, fasting and 2 h glucose, and lipid profile in adult Hong Kong Chinese.

DESIGN

Randomized age and sex stratified survey.

SUBJECTS

One thousand and ten subjects aged 25-74 y (500 men, 510 women) recruited for the 1995-96 Hong Kong Dietary and Cardiovascular Risk Prevalence Survey.

MEASUREMENTS

Dietary intake was estimated using a food frequency method. Information on education level and marital status was included in the questionnaire. Anthropometry and biochemical parameters were measured using standard methods.

RESULTS

After adjustment for age, higher levels of education are associated with higher percentage protein intake in men, higher percentage fat intake in women, higher nutrient density of fibre and calcium in both men and women, and higher nutrient density of protein, fat, niacin, vitamin D, and polyunsaturated fatty acid in women. Consumption of fruits was also higher in women, and that of dairy products higher in men. Body mass index and waist-hip ratio were lower with increasing levels of education in women, while lower mean systolic BP was observed in men. Single women had lower nutrient densities of vitamin D and iron, and lower consumption of vegetables and fish, compared with married women. Body mass index was lower in both single men and women. Single men had a better cardiovascular risk factor profile, in that diastolic BP, triglycerides and cholesterol/HDL ratio were lower, in addition to a lower body mass index.

CONCLUSION

Higher education level is associated with a healthier diet and lower prevalence of overweight.

Axial and peripheral bone mineral acquisition: a 3-year longitudinal study in Chinese adolescents

We performed a 3-year longitudinal study of a group of 179 healthy Chinese adolescents (92 boys and 87 girls) aged from 12 to 16 years to determine the effects of puberty, physical activity, physical fitness, and calcium intake on the acquisition of bone mass. At yearly intervals for 3 consecutive years we recorded nutrition, calcium intake and anthropometric measurements, and assessed pubertal status according to Tanner. Bone mass of the lumbar spine was determined by dual-energy X-ray absorptiometry and radial bone mass by single-photon absorptiometry. Physical fitness and level of physical activity were assessed and muscle strength and power determined by isokinetic testing. Peripheral bone mass correlated with axial skeleton bone mass. Age, pubertal staging, physical fitness and muscle strength were significantly associated with bone mass increments on cross-sectional univariate and regression analysis. Longitudinal regression analysis showed that the most important factor affecting bone mass accretion in adolescents in both sexes was their pubertal stage. In boys, bone mass increment throughout the study was greater in children who were already in the advanced pubertal stages on entering the study than in those who started puberty in year 2 or 3 of the study. The percentage change in bone mineral content of the forearm and in bone mineral density of the lumbar spine was greater than 25% in the advanced pubertal group as compared to around 20% in the less mature group. For girls, the reverse was true. The increment of bone mass during the study period was significantly greater in those who presented in the earlier pubertal stages than in those who were at the more advanced stage of puberty on entry into the study. There was no significant effect of calcium intake and physical activities on the bone mass accretion.

CONCLUSION

In Chinese adolescents, bone mineral accretion at adolescence is not influenced by exercise, level of physical fitness and calcium intake. In both sexes, and especially in girls, to optimally increase bone mass, regular physical exercise programmes should be instituted well before the onset of puberty rather than at or after it. Once puberty starts, these interventions may have no or only limited effect.

Mapping contacts between gRNA and mRNA in trypanosome RNA editing

All guide RNAs (gRNAs) identified to date have defined 5' anchor sequences, guiding sequences and a non-encoded 3' uridylate tail. The 5' anchor is required for in vitro editing and is thought to be responsible for selection and binding to the pre-edited mRNA. Little is known, however, about how the gRNAs are used to direct RNA editing. Utilizing the photo-reactive crosslinking agent, azidophenacyl (APA), attached to the 5'- or 3'-terminus of the gRNA, we have begun to map the structural relationships between the different defined regions of the gRNA with the pre-edited mRNA. Analyses of crosslinked conjugates produced with a 5'-terminal APA group confirm that the anchor of the gRNA is correctly positioning the interacting molecules. 3' Crosslinks (X-linker placed at the 3'-end of a U10tail) have also been mapped for three different gRNA/mRNA pairs. In all cases, analyses indicate that the U-tail can interact with a range of nucleotides located upstream of the first edited site. It appears that the U-tail prefers purine-rich sites, close to the first few editing sites. These results suggest that the U-tail may act in concert with the anchor to melt out secondary structure in the mRNA in the immediate editing domain, possibly increasing the accessibility of the editing complex to the proper editing sites.

Dietary intake and practices in the Hong Kong Chinese population

OBJECTIVES

To examine dietary intake and practices of the adult Hong Kong Chinese population to provide a basis for future public health recommendations with regard to prevention of certain chronic diseases such as cardiovascular disease, hypertension, and osteoporosis.

PARTICIPANTS

Age and sex stratified random sample of the Hong Kong Chinese population aged 25 to 74 years (500 men, 510 women).

METHOD

A food frequency method over a one week period was used for nutrient quantification, and a separate questionnaire was used for assessment of dietary habits. Information was obtained by interview.

RESULTS

Men had higher intakes of energy and higher nutrient density of vitamin D, monounsaturated fatty acids and cholesterol, but lower nutrient density of protein, many vitamins, calcium, iron, copper, and polyunsaturated fatty acids. There was an age related decrease in energy intake and other nutrients except for vitamin C, sodium, potassium, and percentage of total calorie from carbohydrate, which all increased with age. Approximately 50% of the population had a cholesterol intake of < or = 300 mg; 60% had a fat intake < or = 30% of total energy; and 85% had a percentage of energy from saturated fats < or = 10%; criteria considered desirable for cardiovascular health. Seventy eight per cent of the population had sodium intake values in the range shown to be associated with the age related rise in blood pressure with age. Mean calcium intake was lower than the FAO/WHO recommendations. The awareness of the value of wholemeal bread and polyunsaturated fat spreads was lower in this population compared with that in Australia. There was a marked difference in types of cooking oil compared with Singaporeans, the latter using more coconut/palm/mixed vegetable oils.

CONCLUSION

Although the current intake pattern for cardiovascular health for fat, saturated fatty acid, and cholesterol fall within the recommended range for over 50% of the population, follow up surveys to monitor the pattern would be needed. Decreasing salt consumption, increasing calcium intake, and increasing the awareness of the health value of fibre may all be beneficial in the context of chronic disease prevention.

Excisions of the Ikirara1 transposon in an Anopheles gambiae cell line

In order to determine whether there are active genomic copies of the Anopheles gambiae transposon Ikirara, we developed an excision assay based on an internally deleted copy, Ikirara1. This element has 216 bp perfect inverted repeats at its termini, apparently caused a duplication of the dinucleotide TA at its insertion site between vitellogenin genes, and is thought to have been inserted recently at this location. The firefly luciferase gene on the E. coli tac promoter was inserted into Ikirara1 and used as a reporter to assess whether activities in an A. gambiae cell line could cause Ikirara excision. Excisions were observed at a rate of 0.038% in these experiments, but none was detected in controls. The five independent excision products examined gave identical sequences. Excisions were nearly precise, but left behind a footprint of 15 bp of the 3' inverted repeat of Ikirara1 between duplicated TAs. These excisions can be explained by a mechanism formally similar to that proposed for excision of mariner/Tc1 elements with cuts at the transposon ends staggered by 15 bases.

Determinants of axial and peripheral bone mass in Chinese adolescents

OBJECTIVE

To determine the relation of puberty, physical activity, physical fitness, and calcium intake with bone mineral content (BMC) of the distal radius, and on bone mineral density (BMD) of the L2 to L4 vertebrae in a group of healthy Chinese adolescents.

DESIGN

Cross sectional survey.

SUBJECTS

A group of 179 healthy Chinese adolescents (92 boys and 87 girls) aged 12 to 13 years enrolled in the first year of the Tii Junior High School in Shatin, Hong Kong. Ninety four of the pupils enrolled were in the physical education major class (PE), and the other 85 were in the art major class (ARTS).

MAIN OUTCOME MEASURES

Correlation of BMC of the distal radius and BMD of the L2 to L4 vertebrae with level of physical activity, physical fitness (isometric and isokinetic), muscle strength of the upper and lower limb, and calcium intake.

RESULTS

BMC of the distal radius and BMD of the L2 to L4 vertebrae were significantly positively correlated. Univariate and regression analysis showed that age, pubertal staging, physical fitness, and muscle strength were significantly associated with bone mass in a positive way. Calcium intake and type of sport practised did not exert a significant influence on BMC of the distal radius and BMD of the L2 to L4 vertebrae in boys. The results for the BMD of the L2 to L4 vertebrae were similar in girls and boys; however, in girls, the BMC of the distal radius had a negative correlation with calcium intake. Physical fitness was a significant positive predictor of BMD of the L2 to L4 vertebrae.

CONCLUSIONS

Among Chinese adolescents bone mass was positively influenced by certain measures of physical fitness as well as by age, weight, and pubertal stage.

Can we predict body height from segmental bone length measurements? A study of 3,647 children

It is well known that significant differences exist in the anthropometric data of different races and ethnic groups. This is a cross-sectional study on segmental bone length based on 3,647 Chinese children of equal sex distribution aged 3-18 years. The measurements included standing height, weight, arm span, foot length, and segmental bone length of the humerus, radius, ulna, and tibia. A normality growth chart of all the measured parameters was constructed. Statistical analysis of the results showed a very high linear correlation of height with arm span, foot length, and segmental bone lengths with a correlation coefficient of 0.96-0.99 for both sexes. No differences were found between the right and left side of all the segmental bone lengths. These Chinese children were found to have a proportional limb segmental length relative to the trunk.

Body fatness and serum lipids of 11-year-old Chinese children

It has been suggested that distribution of body fat has a stronger bearing on health risk than total body fat. Magnetic resonance imaging (MRI) was used to examine the distribution of fat and correlated with body fat assessed by the usual clinical methods-weight, weight-for-height, body mass index (BMI), triceps and subscapular skinfold thickness in 11-y-old Chinese children. Lipid profiles were used as indicators for coronary risk. Eighty-eight subjects had body fat distribution estimated by MRI, while 49 had serum lipids measured. Anthropometric parameters correlated significantly with total fat at the umbilical level measured by MRI (weight: r = 0.90 in boys, 0.75 in girls; BMI: r = 0.94 in boys, 0.87 in girls; percent median weight-for-height: r = 0.90 in boys, 0.79 in girls, triceps skinfold thickness: r = 0.89 in boys, 0.90 in girls; subscapular skinfold thickness: r = 0.93 in boys, 0.88 in girls). Obese subjects had proportionally less visceral fat than subcutaneous fat at umbilical level. Using stepwise multiple regression, predictive factors for high-density lipoprotein cholesterol were BMI in boys and breast-staging in girls. For triglycerides, it was genital staging in boys and for total cholesterol, it was breast-staging in girls. Visceral fat was not a significant determinant of serum lipids.

Hydration and dehydration behavior of aspartame hemihydrate

Previous studies have shown that aspartame in the solid state can exist as a hemihydrate which occurs in two different polymorphic forms (I and II). The present work shows that equilibration of either hemihydrate at 25 degrees C with water vapor at relative humidities > or = 58% or with liquid water produces a 2.5-hydrate. Upon subjecting each of these crystalline hydrates to increasing temperature, the same crystalline anhydrate is formed which thermally cyclizes at a higher temperature to form the known compound 3-(carboxymethyl)-6-benzyl-2,5-dioxopiperazine. The activation energy of the cyclization reaction appears to depend on the degree of crystallinity of the anhydrate that is formed at a lower temperature. On increasing the temperature of the 2.5-hydrate, a hemihydrate intervenes before the anhydrate is formed. This intervening hemihydrate is similar to the commercial form (II) of aspartame hemihydrate but exhibits greater amorphous character. The techniques employed were Karl Fischer titrimetry, powder X-ray diffractometry, differential scanning calorimetry, thermogravimetric analysis, solid-state 13C nuclear magnetic resonance spectroscopy, and Fourier transform infrared absorption spectroscopy.

Solid-state characterization of two polymorphs of aspartame hemihydrate

From the known crystal structure of aspartame hemihydrate, designated form 1, the theoretical powder X-ray diffraction (PXRD) pattern was calculated. This PXRD pattern differs significantly from that of the commercially available aspartame hemihydrate, which is therefore a different polymorph, designated form II. Form II transforms to form I during ball-milling or on heating for 30 min at 160 degrees C in the presence of steam. The two polymorphs were compared by PXRD, differential scanning calorimetry, thermogravimetric analysis, Karl Fischer titrimetry, Fourier transform infrared (FTIR) absorption spectroscopy, 13C solid-state nuclear magnetic resonance (SSNMR) spectroscopy, scanning electron microscopy, particle size analysis, and measurements of true density and intrinsic dissolution rate. Comparison of the 13C SSNMR and FTIR spectra of the two polymorphs suggests that the crystal structure of form II is less symmetric, with the side chains located in multiple environments. Although both hemihydrate polymorphs on heating in the absence of moisture dehydrate to a crystalline anhydrate, form I does so at a lower temperature, suggesting weaker interactions of water with aspartame molecules. At higher temperatures the anhydrate from both hemihydrate polymorphs yields 3-(carboxymethyl)-6-benzyl-2,5-dioxopiperazine (DKP) by a cyclization reaction for which the temperature, reaction enthalpy, and activation energy are very similar. Both hemihydrate forms, when in contact with liquid water, yield the 2.5-hydrate.

Body mass index reference curves for Chinese children

The Hong Kong Growth Survey 1993 provided data for the construction of reference curves for body mass index (BMI) of Chinese children from birth to 18 years. Data on weight and height was obtained from 11797 boys and 12168 girls. The LMS method was used to smooth the percentile curves. These curves showed a definite physiological rising pattern to a peak at 6 months, then fell to a trough at 6 years, before another rise towards adulthood. Compared to published reports from the US, Britain, France and Sweden, Hong Kong Chinese children, particularly the girls, were less obese. In the first 2 years median curves of Hong Kong Chinese were similar to those of the Japanese.

Body fat estimation in children by magnetic resonance imaging, bioelectrical impedance, skinfold and body mass index: a pilot study

OBJECTIVE

The aim of this study was to identify the clinical method to estimate body fat which gave best correlation of total body fat and percentage body fat as measured on MRI.

METHODS

Magnetic resonance imaging (MRI) was used to estimate the total body fat volume and percentage body fat and this was compared with assessment by bioelectrical impedance (BEI), skinfold thickness and body mass index (BMI) in 8- to 12-year-old children.

RESULTS

Total body fat measured on magnetic resonance imaging (TBF-MRI) significantly correlated with body mass index, triceps and subscapular skinfolds, and percentage body fat estimations by BEI. Multiple regression analysis showed that BMI and BEI together gave the best prediction of total body fat as measured on MRI from the equation: TBF-MRI=-25277.77+1457.61(BMI)+423.95(%fat-BEI), with R2=0.89. Percentage body fat measurement from MRI, BEI and skinfold were not significantly different but their results were not interchangeable. Linear regression of %body fat from MRI on those obtained from BEI and skinfold measurements showed a modest fit with R2=0.6973 and 0.5501, respectively.

CONCLUSIONS

In children 8-12 years old, BMI gives a good estimation of the total body fat as measured on MRI. The estimation will be improved when both BEI and BMI are used in the prediction. Bioelectrical impedance has a low correlation with total body fat and its use alone in estimating total body fat is not recommended. Skinfold measurement also gives a reasonably good prediction of total body fat and addition of BMI and BEI does not improve the prediction. Both BEI and skinfold measurements give a modest prediction of %body fat measured by MRI method.

Breast milk fatty acid composition: a comparative study between Hong Kong and Chongqing Chinese

The fatty acids of milk samples obtained from 51 Hong Kong Chinese and 33 Chongqing Chinese (Si Chuan Province, China) were analyzed by gas-liquid chromatography. Compared with those of published data for Canadian and other Western countries, the Chinese milk from both Hong Kong and Chongqing contained higher levels of longer-chain polyunsaturated fatty acids, particularly docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6). In contrast, the content of trans fatty acids in the Chinese milk was lower compared with those for Canadian and other Western countries. Longitudinally, the concentrations of 22:6n-3 and 20:4n-6 gradually decreased when lactation progressed from colostrum (week 1) to mature (week 6). Over the same interval, linoleic acid (18:2n-6) remained unchanged in Chongqing Chinese but significantly increased in Hong Kong Chinese. Unlike 18:2n-6, linolenic acid (18:3n-3) increased in Chongqing Chinese but remained unchanged in Hong Kong Chinese throughout the study. The total milk fat also increased with the duration of lactation. In addition, the milk of Chongqing Chinese had higher total milk fat than that of Hong Kong Chinese and Canadians. The content of erucic acid (22:1n-9) increased with the progression of lactation in Chongqing Chinese, indicating that there was a switch in dietary consumption from fats of animal origin to rapeseed oil when lactation reached week 6. The present study showed that Hong Kong and Chongqing Chinese had a different fatty acid profile in many ways, which largely reflected a different dietary habit and life-style in these two places.

Plasma total antioxidant capacity in an adult Hong Kong Chinese population

OBJECTIVES

To examine plasma total antioxidant capacity (TAOC) in a Chinese population with a lower incidence of cardiovascular disease compared with Caucasian populations, in relation to dietary intake, age, sex, and the presence of cardiovascular diseases.

DESIGN AND METHODS

As part of a randomized territory-wide survey stratified by sex and 10-year age groups; 728 subjects (367 men, 361 women) were recruited. Dietary intake assessment was by a food frequency questionnaire; plasma TAOC was estimated by the ABTS method.

RESULTS

The TAOC values were normally distributed, the mean +/- SD being 1.78 +/- 0.18 mmol/L. The mean value was higher in men compared with women, inspite of a lower dietary intake of vitamins A and C per 1000 kcal in the former. Subjects who consumed water spinach twice or more a week had higher mean levels. No difference in mean levels was observed between those with and without hypertension or cardiovascular disease.

CONCLUSION

Measurement of plasma TAOC as a risk factor in epidemiological studies of cardiovascular diseases may have limited use, since TAOC include substances associated with a protective effect as well as increased risk.

Secular trend in the sexual maturation of southern Chinese girls

In 1993, a cross-sectional study of sexual maturation of normal Chinese schoolgirls was performed in Hong Kong. The aim of the study was to obtain an up-to-date reference for normal pubertal development in Chinese girls. Breast development was assessed in 3749 girls aged 7-19 y, and pubic hair rating was assessed in 3745 girls. Menstrual status was recorded in 6467 girls over 6 y of age. The median age of onset of puberty as indicated by breast stage II or above was 9.78 (95% CI 9.70-9.85) y. The median age of onset of pubic hair development was 11.64 (95% CI 11.56-11.72) y. The median age of menarche was 12.38 (95% CI 11.98-12.78) years. Percentile values for the age at which each puberty staging appeared were constructed and incorporated into the height-for-age charts. When comparison is made with similar studies done in 1962 and 1979, a significant downward secular trend in sexual maturation is observed (p < 0.01). Except for breast development the downward secular trend in sexual maturation appears to be diminishing and may be coming to a halt in the Chinese girls in Hong Kong. Their median ages of sexual maturation are now among one of the earliest medians recorded in the world population studied.

Change of foot size with weightbearing. A study of 2829 children 3 to 18 years of age

The change of foot length and width with age has been reported in a few anthropometric studies in the literature. However, the relationship with body height rarely is reported, and the dynamic effect of weightbearing on foot size has not been documented. In this series, 2829 children 3 to 18 years of age of equal gender distribution were included in the study. The foot length and width on weightbearing and nonweightbearing were measured with a special precision electronic caliper. The foot length and width were found to increase linearly from the age of 3 years until 12 years in girls and 15 years in boys. This was followed by a phase during which the increase plateaued. The foot length and width increased significantly on weightbearing at all ages in both genders with a mean of 2.1 to 4.4 mm or 3.1% to 4.8%, respectively. The foot length and width also were found to correlate significantly with the body height in both genders, with a correlation coefficient of 0.96 to 0.98. No significant differences were found between the sizes of the dominant and nondominant foot in either gender.

Dietary practices and lipid intake in relation to plasma lipid profile in Hong Kong Chinese

OBJECTIVE

To study dietary lipid intake and plasma lipid profile of the Hong Kong Chinese population as part of a territory wide survey on cardiovascular risk factors.

DESIGN

Randomised age and sex stratified survey.

SUBJECTS

1010 subjects aged 25-74 y (500 men, 510 women).

MEASUREMENTS

A food frequency method with food tables compiled for Hong Kong was used for nutrient quantitation, while a separate questionnaire was used to examine dietary practices. Plasma lipid profile was estimated using standard laboratory methods.

RESULTS

Total calorie, fat, saturated fatty acid (SFA), poly- and mono-unsaturated fatty acid (PUFA and MUFA), and cholesterol intake were higher in men; however when adjusted for caloric intake no difference was observed. Men had lower intake of PUFA as percentage of total energy had a higher Hegsted Score compared with women. Subjects consuming beans twice or more per week had lower total cholesterol and LDL-cholesterol concentrations. Overall, the population dietary intake was close to the ideal for cardiovascular health: percentage fat not greater than 30% of the total calorie intake, saturated fat intake not greater than 10% of calories, and cholesterol less than 180 mg/1000 Kcal.

CONCLUSION

The dietary pattern for Hong Kong Chinese appear to be satisfactory with respect to cardiovascular health.

Bone mineral acquisition in low calcium intake children following the withdrawal of calcium supplement

Our recent 18-month calcium supplementation trial demonstrated a significant increase in radial bone mineral mass in 7-year-old children with calcium intake approximately 300 mg/day (Am J Clin Nutr 1994; 60: 744-50). The persistence of higher bone mass after cessation of calcium supplementation is unknown. This is a follow-up study to investigate the lasting effect of calcium supplementation on bone acquisition. Subjects were 159 Chinese children aged 8.7 years. Distal one-third radial bone mineral content (BMC) and bone width (BW) were measured by single-photon absorptiometry. After 12 months, the significant difference in mean +/- SD percentage radial BMC disappeared between the study and control groups (7.34 +/- 6.77% vs 8.67 +/- 6.46%, p > 0.05). Dietary calcium intakes were similar between the groups. During the supplementation phase, the study group had 17.9% greater BMC gain than that of controls. In the follow-up phase, however, the study group had 16.1% less BMC gain than that of controls. It appears that an increased acquisition rate during the supplementation phase was almost balanced by a reduced acquisition rate during follow-up phase. Moreover, throughout the entire 30-month period, the overall BMC acquisition rates of the study and control groups were 25% and 23.8%, respectively. Hence, the overall acquisition rate of the study group was only 5% higher than that of controls. Therefore, the effect of calcium supplementation on bone mineral gain appears to reflect a transient reduction in bone turnover rate. Longer-term calcium trials are necessary to confirm whether a sustainable higher calcium intake throughout childhood will enhance peak bone mass.

Chronic illness perception in adolescence: implications for the doctor-patient relationship

OBJECTIVE

To describe the inter-relationship of chronic illness severity as perceived by adolescents with both psychosocial well-being and objective measures of illness severity. Additionally to compared the adolescents' perception of illness severity with how their physicians believe that the adolescents perceive their illness severity.

METHODS

The psychological well-being of 48 adolescents with either cystic fibrosis (CF) or insulin-dependent diabetes mellitus (IDDM) was measured by four standardized questionnaires. The adolescents' perception of severity of illness was measured using an original instrument (PSCI), and this measure was compared to their physicians' estimates of how the adolescents perceived the severity of their illness and clinical illness.

RESULTS

There were 24 patients in both the CF and IDDM groups. Both groups were found to function well psychosocially; although, there were more patients with low self image compared to normative values. Depression and low self image were associated with a greater adolescent perception of illness severity. For both chronic illness groups, physicians' assessment of assumed adolescent perception of disease severity correlated with clinical indices of disease severity and was higher than the perception of illness severity reported by the adolescents. For adolescents with CF, but not with IDDM, perception of severity of chronic illness correlated with clinical indices.

CONCLUSIONS

For adolescents with chronic illness, their perception of illness severity is an important indicator of psychosocial well-being. Physicians do not accurately infer their patients' perception of illness severity.

Solid state stability studies of model dipeptides: aspartame and aspartylphenylalanine

Some solid-state pharmaceutical properties and the solid-state thermal stability of the model dipeptides aspartame (APM) and aspartylphenylalanine (AP), have been investigated. Studies by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), high-performance liquid chromatography, powder X-ray diffraction, and optical microscopy have shown that the dipeptides undergo solid state intramolecular aminolysis of the type, solid --> solid + gas. This reaction was observed for APM at 167-180 degrees C with the liberation of methanol and for AP at 186-202 degrees C with the liberation of water. The exclusive solid product of the degradation reaction of both dipeptides is the cyclic compound 3-(carboxymethyl)-6-benzyl-2,5-dioxopiperazine. The rates of the degradation reactions were monitored by isothermal TGA and by temperature-ramp DSC and were found to follow kinetics based on nucleation control with activation energies of about 266 kJ mol(-1) for APM and 234 kJ mol(-1) for AP.

A follow-up study on the effects of calcium-supplement withdrawal and puberty on bone acquisition of children

Recent calcium supplementation trials in children have confirmed a positive but moderate effect of calcium intake on bone mineral accretion. However, the lasting effect of a higher bone mineral mass after calcium-supplement withdrawal is not known. This is an 18-mo follow-up study conducted after an 18-mo controlled calcium supplementation trial to study the persistent effect of higher bone mineral mass in children. Radial bone mineral mass was determined by single-photon absorptiometry; lumbar spine and femoral neck bone mineral mass were evaluated by dual-energy X-ray absorptiometry in 84 healthy Hong Kong children at age 8.5 y and these evaluations were repeated at age 10 y. Pubertal status was determined by Tanner staging. At the end of the follow-up, the differences in percentage gains in lumbar spine bone mineral content (12.1 +/- 8.2% compared with 14.9 +/- 10.05%, P = 0.24) and lumbar spine area (8.6 +/- 5.1% compared with 9.4 +/- 5.5%, P = 0.47) between the study and control groups disappeared. Dietary calcium intakes during follow-up were similar for the two groups (555 and 640 mg/d, P = 0.23). In multiple-regression analyses, pubertal status was the strongest correlate of bone acquisition and linear growth in the study period. In conclusion, higher percentage gains in bone mineral mass in childhood by calcium supplementation for 18 mo were reversible. Our study showed that the benefits of calcium supplementation disappear after treatment is withdrawn. Longer-term calcium trials are necessary to determine whether peak bone mass can be modified through sustained supplementation so that appropriate calcium intakes can be determined.

Secular changes in standing height, sitting height and sexual maturation of Chinese--the Hong Kong Growth Study, 1993

In 1993 a territory-wide cross-sectional growth survey on 25,000 Chinese children from birth to 18 years was performed in Hong Kong. Compared to the last growth survey in 1963, definite secular changes were observed. There was an increase of final adult standing height of 3.6 cm in boys and 2.7 cm in girls, in which 1.8 cm and 0.5 cm respectively for boys and girls was accounted for by the sitting height. Thus most of the height increase had occurred in the leg length in girls, but in boys only half of it. The height difference was more marked during the pubertal years because secular change had brought about an earlier sexual maturation, including an advancement of median menarcheal age by 0.5 year, coupled with an earlier growth spurt. This paper also provides the first growth standards for Chinese from birth to 18 years, with percentile charts on both standing height and sexual maturation in boys and girls.

Secular trend in the sexual maturation of southern Chinese boys

A random sample of 3872 southern Chinese boys ranging from 7 to 21 years of age were selected from primary and secondary schools in Hong Kong for the assessment of sexual maturation. The median ages of onset of puberty and pubic hair development were 11.4 and 12.7 years, respectively. The advancement of sexual maturation coincides with the secular increase in height and weight for Chinese children in Hong Kong.

Weight-for-age and weight-for-height references for Hong Kong children from birth to 18 years

OBJECTIVE

Childhood obesity is an emerging problem in Asia. Sequential monitoring of the growth of an individual can detect a change in body fatness, provided there are ethnically appropriate growth references.

METHODOLOGY

A territory wide cross-sectional growth survey of Hong Kong on 24709 individuals from the age of newborn to 18 years was performed in 1993. Weight-for-age and weight-for-height percentile charts were prepared separately for boys and girls.

RESULTS

There was an average increase of 8.5 kg and 5.1 kg in the 18 year old boys and girls, respectively, compared to those surveyed 30 years ago. The percentile curves between 6 and 18 years were similar to those of Singapore. Weight-for-height percentile curves were close to those of America in the prepubertal years.

CONCLUSIONS

These Hong Kong growth standards for weight-for-age and weight-for-height are important tools for the assessment of nutritional status of an individual and for monitoring changes in nutritional status of the population.

Anthropometric measurements and body proportions among Chinese children

There are significant racial differences in body proportions. Such data are not readily available for Chinese children. This article reports a cross section study of body proportions of 2193 Hong Kong Chinese children, ages 4 to 16 years, with equal gender distribution. Standing height, sitting height, and arm span were measured with standard equipment and methodology. Lower segment height was calculated as the difference between standing height and sitting height. Statistical analysis of the results showed a high linear correlation of the standing height with arm span, sitting height, and lower segment height, with a correlation coefficient ranging from 0.965 to 0.983 for both genders. When expressed as the ratio of standing height to arm span, the value was relatively constant and changed only linearly from 1.03 to 1 in girls and 1.03 to 0.98 in boys ages 4 to 16 years. The ratio of sitting height to lower segment height varied from a mean of 1.4 to 1.14 in boys and 1.36 to 1.18 in girls ages 4 to 16 years. The Chinese children were found to have a proportional limb segmental length relative to the trunk that differed significantly from the proportionally longer limbs in whites and blacks.

[Prevalence of obesity in Hong Kong children and adolescents aged 3-18 years]

A cross-sectional study on growth and development in Hong Kong children and adolescents ranging from their birth to 18 years of age was performed in 1993 and all the growth standards were constructed in the form of percentile chart. Those having a weight at one's median weight for height standard of 120% were defined as obesity. Prevalence of obesity in children and adolescents aged 3-18 was 10.08% (11.28% and 8.93% for boys and girls, respectively), which was higher than that in the inland of the country and that in Hong Kong as previously reported. Result showed there was a gradual increase in the prevalence after the age of 5, which reached a peak at the age of 11 for boys and 8 for girls.

A randomized double-blind controlled calcium supplementation trial, and bone and height acquisition in children

There is limited information relating Ca intake to bone and height acquisition among Oriental children who consume little or even no milk. The present controlled study investigated the acquisition of bone mass and height of Chinese children with an initial Ca intake of approximately 567 mg/d who were supplemented to about 800 mg/d. Eighty-four 7-year-old Hong Kong Chinese children underwent an 18-month randomized, double-blind, controlled Ca-supplementation trial. The children were randomized to receive either 300 mg elemental Ca or a placebo tablet daily. Bone mass of the distal one-third radius was measured by single-photon absorptiometry, lumbar spine and femoral neck were determined using dual-energy X-ray absorptiometry. Measurements were repeated 6-monthly. Baseline serum 25-hydroxycholecalciferol concentration and physical activity were also assessed. Baseline Ca intakes of the study group and controls were respectively 571 (SD 326) and 563 (SD 337) mg/d. There were no significant differences in baseline serum 25-hydroxycholecalciferol concentration (P = 0.71) and physical activity (P = 0.36) between the study and control groups. After 18 months the study group had significantly greater increases in lumbar-spinal bone mineral content (20.9 v. 16.34%; P = 0.035), lumbar-spinal area (11.16 v. 8.71%; P = 0.049), and a moderately greater increment in areal bone mineral density of the radius (7.74 v. 6.00%; P = 0.081) when compared with the controls. The results confirm a positive effect of Ca on bone mass of the spine and radius but no effects on femoral-neck and height increase. A longer trial is warranted to confirm a positive Ca effect during childhood that may modify future peak bone mass.