"Bridge population": sex workers or their clients?--STI prevalence and risk behaviors of clients of female sex workers in China

As the HIV/AIDS epidemic and the spread of sexually transmitted infections (STIs) in China has come to the forefront of public health attention, female sex workers (FSWs) and their clients (CFSWs) are becoming increasingly important to HIV/STI prevention efforts. This secondary analysis uses data abstracted from the Chinese Health and Family Life Survey 1999-2000 to report prevalence rates of two STIs as well as sexual risk behaviors for CFSWs - men who paid for sex with FSWs in the past 12 months - in comparison with men who had not patronized FSWs. Among 1879 Chinese CFSWs who completed anonymous interviews and urine testing, 152 (6.3%, weighted) said they had paid for sex in the past 12 months and 18.8% of CFSWs (weighted) tested positive for gonorrhea. CFSWs were 10 times more likely to have an STI (either self-reported or tested) than non-client Chinese men, and they were equally likely to use condoms inconsistently with their spouses. This study highlights the importance of studying CFSWs who use condoms inconsistently and do not practice safe sex with their spouse as a potential bridge population. Prevention and intervention efforts should target this bridge population and include education on HIV/AIDS and STI transmission, condom promotion, marriage counseling, destigmatization of HIV and STIs, and promotion of STI diagnosis and treatment.

Prevalence and risks for sexually transmitted infections among a national sample of migrants versus non-migrants in China

This study aims to describe and compare the gender-specific prevalence of chlamydia and gonorrhoea, sexual behaviours and experiences, and risk factors associated with sexually transmitted infections (STIs) among migrants versus rural and urban non-migrants in China. Data were abstracted from the Chinese Health and Family Life Survey conducted from 1999 to 2000, which provided a nationally representative adult (ages 20-64 years) sample. STI results were determined using a urine-based nucleic acid amplification assay. The prevalence of chlamydia for migrant women was triple that of rural non-migrant women. Migrants were more likely to engage in STI-associated risk behaviours than non-migrants (e.g. receiving money for sex). Among migrants, women were more likely than men to have STIs. The high STI prevalence among migrants highlights an urgent need to implement comprehensive prevention and intervention programmes targeting the cultural, social and structural needs of migrants in the city, especially migrant women.

Superconductivity at 52.5 k in the lanthanum-barium-copper-oxide system

A superconducting transition with an onset temperature of 52.5 K has been observed under hydrostatic pressure in compounds with nominal compositions given by (La(0.9)Ba(0.1))(2) CuO4-Y. Possible causes for the high-temperature superconductivity are discussed.

Migration and illicit drug use among two types of male migrants in Shanghai, China

Large-scale internal migrations within China have led to speculation of increased drug use, but with little empirical evidence. This cross-sectional study examines the association between migration characteristics and illicit drug use in 100 general male migrants and 239 "money boys" (i.e., male migrants engaging in same-sex transactional sex) in Shanghai, China. Only three general male migrants reported any drug use. Among money boys, lifetime illicit drug use was 12%; Ecstasy and methamphetamine appeared to be the most popular drugs. In addition, depression prevalence was very high among both types of male migrants. Depression was associated with lifetime soft- and hard-drug use, while earning a higher income was associated with lifetime soft-drug use. These findings provide the first set of quantitative evidence of illicit drug use among Chinese male migrants. Although illicit drug use among male migrants is low compared to Western countries, its resurgence after 30 years of drug control gives cause for concern.

Development of GABA innervation in the cerebral and cerebellar cortices

In many areas of the vertebrate brain, such as the cerebral and cerebellar cortices, neural circuits rely on inhibition mediated by GABA (gamma-aminobutyric acid) to shape the spatiotemporal patterns of electrical signalling. The richness and subtlety of inhibition are achieved by diverse classes of interneurons that are endowed with distinct physiological properties. In addition, the axons of interneurons display highly characteristic and class-specific geometry and innervation patterns, and thereby distribute their output to discrete spatial domains, cell types and subcellular compartments in neural networks. The cellular and molecular mechanisms that specify and modify inhibitory innervation patterns are only just beginning to be understood.

Substance use and HIV risks among male heterosexual and ‘money boy’ migrants in Shanghai, China

There is a growing awareness that internal migration in China might shift the HIV epidemic by broadening the social and sexual mixing of its population. However, little is known about how drug use/abuse might contribute to the spread of HIV. This qualitative study aims to elucidate factors for preventing substance abuse and HIV among two types of male migrants living in the Shanghai metropolitan area; the general migrant population and so-called 'money boys' (those who engaged in same-sex activities for money). Compared to most male migrants, the 'money boys' had a slightly better economic situation; rarely visited their hometowns; used alcohol less but drugs more; had more knowledge about HIV and sexually transmitted diseases; higher HIV/ STD testing rates and fewer HIV risk behaviors. The general male migrants had more misconceptions about HIV (e.g. the need to pay for HIV testing) than the 'money boys'. However, it was noted that 'money boys' who were new to the enterprise and men who have sex with men but did not engage in commercial sex often lacked HIV knowledge and protective skills. Given the needs of various sub-types of 'migrants', differential approaches to HIV prevention are needed.

Metabolic and neuropsychological phenotype in women heterozygous for ornithine transcarbamylase deficiency

We compared neurocognitive indices with clinical status, mutation analysis, and urea synthetic capacity in 19 women heterozygous for ornithine transcarbamylase deficiency. Although as a group, these women had average IQ scores, they displayed a specific neuropsychological phenotype with significant strengths in verbal intelligence, verbal learning, verbal memory, and reading, and significant weaknesses in fine motor dexterity/speed and nonsignificant weaknesses in nonverbal intelligence, visual memory, attention/executive skills, and math. This suggests selective vulnerability of white matter and better preservation of gray matter. When the group was divided into symptomatic and asymptomatic subgroups, based on either clinical history or residual urea synthetic capacity, the asymptomatic subgroup outperformed the symptomatic subgroup on all tested domains of neuropsychological functioning. Furthermore, the amount of residual urea synthetic capacity was predictive of several end point cognitive measures. There was no correlation between neonatal versus late-onset mutation or between normal or abnormal allopurinol challenge and neuropsychological outcome. In sum, we identified a specific metabolic and neurocognitive phenotype in women heterozygous for ornithine transcarbamylase deficiency. The findings support the importance of maintaining meticulous metabolic control in children with urea cycle disorders, because even mildly symptomatic subjects demonstrate cognitive deficits.

[Detection of the wheat salt-tolerant-mutant using PCR-SSCP combining with direct sequenceing]

gf-2.8 is a gene located on the chromosomal homologous group 4, which was reported to have relationship with salt tolerance of wheat. A pair of primers were designed to amplify the coding region of gf-2.8 in the two salt-tolerant mutants and their parents. Agarose gel electrophoresis showed that the 685 bp band was amplified among all the materials. SSCP analysis suggested that 974915 (one of the mutants) was different from the other materials. The sequencing results showed that Jimai 24 and its salt-tolerant mutant 8901-17 had the same sequence as published, which indicated that the mutation site of 8901-17 was not on the gf-2.8 gene. However, there were at least two single base mutations in the gf-2.8 of 974915, one of which caused the alternation of amino acid, this mutation occurred in the conservative region of gf-2.8.

[Comparative studies of mitochondrial DNA of T-type cytoplasmic male sterile lines and their maintainers in wheat]

mtDNAs of T type wheat cytoplasmic male sterile lines 75-3369A and their maintainers 75-3369B were isolated and digested completely with restriction endonuclease BamH I, EcoR I, Hind III. The mitochondrial genomic difference between CMS line and maintainers were revealed by Southern hybridization with probes of atp6 from Oenothera and nad3/rps12, cox I from wheat mitochondria. Southern hybridization showed the differences between these two lines. Discussion was made on the change of the DNA composition and the male sterile cytoplasm.

Pediatric Milliman and Robertson length-of-stay criteria: are they realistic?

OBJECTIVE

Guidelines for inpatient length of stay (LOS) have been developed by several groups; among the most widely applied are those published by Milliman and Robertson (M&R). Few published reports have examined the relationship of actual practice to such guidelines, none in pediatric populations. This study was designed to compare pediatric practice in a large and defined population to M&R LOS criteria.

METHODS

Administrative data from New York State in 1995 were used to examine LOS for discharges corresponding to 16 selected pediatric diagnoses for which M&R publishes guidelines. Outliers, defined as the 2% of discharges with the longest LOS, were eliminated. The distribution of LOS for each diagnosis was compared with M&R LOS guidelines.

RESULTS

In New York State during 1995, pediatric LOS was markedly divergent from M&R guidelines. In general, the percentage of discharges in excess of the criterion LOS was less for nonmandatory admissions (croup: 23%, gastroenteritis: 44%, and pneumonia: 48%) than for those requiring surgery (uncomplicated appendectomy: 67%, pyloromyotomy: 62%, and major but noncritical burns: 64%) or prolonged treatment with antibiotics (bacterial meningitis: 91% and osteomyelitis: 86%).

CONCLUSIONS

In New York State during 1995, LOS for selected pediatric conditions was generally in excess of published M&R guidelines. This raises concern about the potential effects of such guidelines on both patients and the hospitals caring for them. While endorsing the need for cost-effective practice, we call attention to the methods used to develop and validate guidelines.length of stay, pediatrics, managed health care, administrative data, practice guidelines.

Brain-derived neurotrophic factor overexpression induces precocious critical period in mouse visual cortex

Brain-derived neurotrophic factor (BDNF) is a candidate molecule for regulating activity-dependent synaptic plasticity on the grounds of its expression pattern in developing visual cortex and that of its receptor, trkB (Castr¿n et al., 1992; Bozzi et al., 1995; Schoups et al., 1995; Cabelli et al., 1996), as well as the modulation of these patterns by activity (Castr¿n et al., 1992; Bozzi et al., 1995; Schoups et al., 1995). Infusing trkB ligands or their neutralizing agents, the trkB-IgG fusion proteins, into visual cortex alters the development and plasticity of ocular dominance columns (Cabelli et al., 1995; Riddle et al., 1995; Galuske et al., 1996 ; Gillespie et al., 1996; Cabelli et al., 1997). To test further the physiological role of BDNF, we studied a transgenic mouse that expresses elevated levels of BDNF in primary visual cortex (V1) postnatally (Huang et al., 1999). We found that unlike the infusion experiments, excess BDNF expressed in mouse visual cortex did not block ocular dominance plasticity. Instead, single neurons in V1 of the BDNF transgenic mice were as susceptible to the effects of monocular deprivation (MD) as neurons in wild-type mice, but only during a precocious critical period. At a time when V1 in the wild-type mouse responded maximally to a 4 d MD with a reduction in its response to deprived eye visual stimulation, the transgenic mouse V1 had already passed the peak of its precocious critical period and no longer responded maximally. This finding suggests a role for BDNF in promoting the postnatal maturation of cortical circuitry.

[Segmental analysis of hair from meperidine abusers and evaluation of the results]

Using meperidine abusers as subjects for this study, we detected in hair meperidine and its metabolites normeperidine, N-OCH3-meperidine and N-AC-meperidine. The content of meperidine and normeperidine of 60 abusers were 103 +/- 130 ng/mg and 117 +/- 143 ng/mg respectively. Meperidine was stably present in hair for at least 20 months. Normeperidine level decreased from hair root to tip. The segmental analysis of hair revealed that there were correlations between the drug abuse history and the distribution of drug along the hair shaft, and between the dose of meperidine and its content presented in hair.

[Determination of heroin metabolites in biological fluids, tissues and hair of heroin addicts using GC/MS-SIM]

Using GC/MS-SIM, we examined morphine distribution in human bodies of 2 delayed death cases and analyzed content of morphine and 6-acetylmorphine (MAM) in hair specimens of 7 cases. After hydrolysis and extraction, MOR and 6-MAM were derived with acetic anhydride or BSTFA and then the derivatives were qualitatively and quantitatively analyzed by GC/MS-SIM. The results indicated that urine, bile and liver were the best samples to reveal the heroin-related deaths. Hair analysis has its unique advantage for its long time of abusing monitor, compared to biological fluids.

BDNF regulates the maturation of inhibition and the critical period of plasticity in mouse visual cortex

Maturation of the visual cortex is influenced by visual experience during an early postnatal period. The factors that regulate such a critical period remain unclear. We examined the maturation and plasticity of the visual cortex in transgenic mice in which the postnatal rise of brain-derived neurotrophic factor (BDNF) was accelerated. In these mice, the maturation of GABAergic innervation and inhibition was accelerated. Furthermore, the age-dependent decline of cortical long-term potentiation induced by white matter stimulation, a form of synaptic plasticity sensitive to cortical inhibition, occurred earlier. Finally, transgenic mice showed a precocious development of visual acuity and an earlier termination of the critical period for ocular dominance plasticity. We propose that BDNF promotes the maturation of cortical inhibition during early postnatal life, thereby regulating the critical period for visual cortical plasticity.

[Determination of metabolites of heroin in urine and discrimination of heroin abuse]

This article describes a sensitive method that detects morphine, 6-monoacetylmorphine, morphine-3-glucuronide and codeine in urine for qualifying the abuse of heroin. The analytes were extracted by solid phase C18. The limits of detection (LOD) for morphine and codeine were 50 ng/ml and 50 ng/ml, respectively. The RSD of morphine and codeine were 11.3% (n = 5), and 14.2% (n = 5) respectively. For urine, it does not need to be hydrolyzed before extracted, and for all analytes, also need not to be derivated. The difference ratio of morphine and codeine in the chromatography can be used to discriminate between the abuse of heroin and the administration of compound liquorice mixture.

[Analysis of penicillins in whole blood by reversed high-performance liquid chromatography]

A reversed-HPLC method was established to determinate penicillins in whole blood. Thiamphenicol as internal standard was added to 0.5 ml blood. Proteins in blood were precipitated with acetonitrile, then the separate supernatant was directly injected onto the chromatography column. The range of five penicillins' linearities was 0.9918 to 0.9996, their range of relative recovery was 91.75% to 107.33%, their CV was 3.56% to 9.85%. Effects of different storage temperatures on the stability of analytes and interference of other antibiotics were also studied.

Immobilization of oligonucleotides onto a glass support via disulfide bonds: A method for preparation of DNA microarrays

The covalent attachment of disulfide-modified oligonucleotides to a mercaptosilane-modified glass surface is described. This method provides an efficient and specific covalent attachment chemistry for immobilization of DNA probes onto a solid support. Glass slides were derivatized with 3-mercaptopropyl silane for attachment of 5-prime disulfide-modified oligonucleotides via disulfide bonds. An attachment density of approximately 3 x 10(5) oligonucleotides/microm2 was observed. Oligonucleotides attached by this method provided a highly efficient substrate for nucleic acid hybridization and primer extension assays. In addition, we have demonstrated patterning of multiple DNA probes on a glass surface utilizing this attachment chemistry, which allows for array densities of at least 20,000 spots/cm2.

Effects of reflection-induced retardance on the immunity of bulk optic-material current sensors

Reflection-induced phase retardance inside bulk optic-material current sensors makes the state of polarization of the light change, which reduces the immunity of the sensors against electromagnetic interference. These effects are analyzed theoretically for the first time, to our knowledge. A comparison between the theoretical analysis and the experimental results are given.

Numerical simulation of mass transfer in porous media of blood vessel walls

The tunica media of a blood vessel wall is modeled as a heterogeneous medium composed of a periodic array of cylindrical smooth muscle cells and a continuous interstitial fluid phase of proteoglycan and collagen fibers. By applying Brinkman's model to describe the behavior of the interstitial flow, we obtain an analytical solution for the transmural flow field through the periodic array of smooth muscle cells in the form of a power series, making it possible to compute the convection of solutes in the interstitial phase. With reaction of solutes at the surface of smooth muscle cell membranes being treated as boundary conditions and the diffusion of species being limited to the interstitial fluid phase only, mass transfer in the media of blood vessel walls is simulated numerically using Cray supercomputers. It is found that the Sherwood number (the dimensionless mass-transfer coefficient) is not only constant for all interior smooth muscle cells but also minimally sensitive to changes of parameters controlling the relative rates of diffusion and convection in the interstitial fluid phase and the reaction on the smooth muscle cell surface. In addition, the Sherwood number is not very sensitive to changes in the volume fraction of smooth muscle cells. A homogeneous, one-dimensional model (effective-medium model) is also developed to predict the bulk concentration profile in the media, based on the equivalent properties of the effective medium derived from the heterogeneous medium. A comparison of results from the one-dimensional model and two-dimensional simulation is quite satisfactory for all practical ranges of parameters. It is also determined that, for a small molecule such as ATP, the mass transfer to the surface of smooth muscle cells is "reaction limited" as assumed previously in the literature, whereas, for a large molecule such as low-density lipoprotein, the mass transfer might not be reaction limited.

[Level and trend on injuries among Chinese population]

In this paper, epidemiological distribution and trend on injuries of Chinese population are described, and at the same time, characters and proportion of injuries to the total deaths are analyzed according to data in National Disease Surveillance Point system (DSP). Some important injuries and variance in population by different sexes, age groups and places are analyzed in detail. The death rate on suicide of Chinese population is high, reaching 19.58/10(5). The rate of suicide among females is higher than males, especially in female population of 20-34 age group, proportion is 46.70% to female total suicide. Rate of suicide of old people is also very high, population of over 60 years olds. It counts 29.72% to the total. The death rate due to transportation is going up, from 9.82/10(5) in 1991 to 14.32/10(5) in 1995, with an annual average incseasing ratio 7.84%. Drowning is the major cause of injuries for children of 0-14 years old, proportion of their death is 56.56% to the total death of drowning, 46.48% among them is children of 1-4 years old.

Polarization-preserving totally reflecting prisms with a single medium layer

When reflectors with layers are used at non-normal incidence, the two planes of polarization generally have different phase shifts. The difference in the shifts is known as phase retardance. For prisms with a single layer, this retardance depends on four factors: prism index, layer index, the ratio of the optical thickness of the layer to the wavelength, and angle of incidence. When the retardance is kept at zero and the reflectance for both p and s components of a polarized light are controlled at almost 100% after reflection, a polarization-preserving total reflection is realized. Polarization-preserving totally reflecting prisms (PPTRP's) have many applications in scientific research and optical engineering. Designers of the PPTRP's need references concerning the phase properties of the PPTRP's. However, few papers can be found in which the effects of the four factors on the retardance of the PPTRP's were investigated and compared thoroughly, although the theory concerned has been known and the influences from some (not all) factors have been reported. Therefore it is still necessary to study the behavior of the PPTRP's from all aspects. The effects of all four factors on the retardance are analyzed and compared from all aspects. A general method of designing PPTRP's is proposed. As an example, a special PPTRP is designed and both theoretical and experiment results are given.

[Priorities of disease control in China--analysis on mortality data of National Disease Surveillance Points System]

The leading health problems in the Chinese population are analyzed with indices as standard death rate, YPLL and DALY, using data from The Chinese Diseases Surveillance Points System (DSP). Disease pattern in China is different from that in the 1950's owing to demographic transition (aging of the population), decrease of both morbidity and mortality of communicable disease etc. That made chronic disease relatively more important the increase of some risk factors, directly cause the rising of mortality and morbidity of some chronic diseases and injuries related to lung cancer and transportation. At present the character of the disease pattern is as follows: there is still a long way to go to control communicable diseases, although the incidence rates and proportion have decreased. Meanwhile, chronic diseases and injuries are becoming major health issues. Hence, China is facing double challenges.

PER protein interactions and temperature compensation of a circadian clock in Drosophila

The periods of circadian clocks are relatively temperature-insensitive. Indeed, the perL mutation in the Drosophila melanogaster period gene, a central component of the clock, affects temperature compensation as well as period length. The per protein (PER) contains a dimerization domain (PAS) within which the perL mutation is located. Amino acid substitutions at the perL position rendered PER dimerization temperature-sensitive. In addition, another region of PER interacted with PAS, and the perL mutation enhanced this putative intramolecular interaction, which may compete with PAS-PAS intermolecular interactions. Therefore, temperature compensation of circadian period in Drosophila may be due in part to temperature-independent PER activity, which is based on competition between inter- and intramolecular interactions with similar temperature coefficients.

Temporally regulated nuclear entry of the Drosophila period protein contributes to the circadian clock

The Drosophila period protein (PER) is a predominantly nuclear protein and a likely component of a circadian clock. PER is required for daily oscillations in the transcription of its own gene and thus participates in a circadian feedback loop. In this study, key pacemaker neurons of the Drosophila brain were examined to determine whether the subcellular distribution of PER changes with the time of day. Indeed, PER was found to accumulate in the cytoplasm for several hours before entering the nucleus during a narrow time window. Three long-period mutations (perL) cause a delay in the timing of nuclear translocation and a further delay at elevated temperature. The data indicate that regulation of PER nuclear entry is critical for circadian oscillations by providing a necessary temporal delay between PER synthesis and its effect on transcription.