Search PubMed⌕ Search

Biomedical subjects

J Fang

Publications and source records attributed to J Fang.

At least 253 records · Page 14Linked to original sources
PubMed1996

The association between birthplace and mortality from cardiovascular causes among black and white residents of New York City.

BACKGROUND: Life expectancy is shorter and mortality from cardiovascular disease higher among blacks than among whites in the United States. We studied whether place of birth was associated with mortality from cardiovascular causes among non-Hispanic black and white residents of New York City. METHODS: We linked mortality records from 1988 through 1992 with 1990 U.S. census data for New York City. Mortality data for blacks born in the U.S. South and Northeast and in the Caribbean were compared with those for whites born in the Northeast. RESULTS: Among blacks, the rates of overall mortality and mortality from cardiovascular causes exceeded those among whites. Among persons born in the Northeast, the rates of death from cardiovascular disease for white men (285 per 100,000), as compared with black men (299), and for white women (155), as compared with black women (165), were similar. However, Southern-born black men and women both had mortality from cardiovascular disease that was substantially higher than that of their counterparts born in the Northeast, and Caribbean-born blacks had rates substantially lower than their Northeastern-born counterparts. The differences among the groups in the rates of death from coronary heart disease were greater than those for death due to stroke or hypertension. In each category defined by age and sex, Caribbean-born blacks had significantly lower rates of death from coronary heart disease than did whites. Black men who were 25 to 44 years of age and were born in the South had a rate of death from coronary heart disease that was 30 percent higher than that of Northeastern-born blacks, and four times that of Caribbean-born blacks of the same sex and age. CONCLUSIONS: The higher rate of mortality from cardiovascular causes among blacks, as compared with whites, in New York City masks substantial variation among blacks based on their place of birth.

Adult↗
PubMed1996

Measurement of the Surface Elasticity of an Adsorbed Monolayer by Continuous Surface Deformation

The elasticity of a monolayer adsorbed from a surfactant solution is considered by continuous surface deformation. For all kinds surface deformations a single relation between the elasticity and the effective time should be obtained (master curve). This effective time depends on the rate of deformation and on the kind of deformation. The relation between elasticity and effective time was proven experimentally for a decanoic acid solution at a concentration 10(-7) mol cm-3. The following surface deformations are considered: (i) expansion at a constant dilatation rate, (ii) compression at a constant dilatation rate, (iii) linear expansion, (iv) linear compression, and (v, vi) compression and expansion in a some what more complicated way. From these data the Gibbs elasticity and the diffusion relaxation time are obtained. These parameters are also obtained by longitudinal wave method of Lucassen-Van den Tempel. Both set of parameters are comparable. Finally the situation at a growing drop with constant flow rate is considered (Triton X-100) to show that also here the approach is followed.

Journal Article↗
PubMed1996

Sex differences in paradoxical sleep: influences of estrus cycle and ovariectomy.

Previously, we reported that paradoxical sleep (PS) is sexually dimorphic in mice and rats. Since some early studies indicate that PS is suppressed during proestrus night, it is important to know whether the estrus cycle and accompanying circulating ovarian hormones could explain the sexual dimorphism of PS. To examine this, sleep patterns of male rats were compared with those of normal cycling female rats and ovariectomized females in a 12:12 h light/dark cycle. Slow wave sleep and total sleep time are indistinguishable between the males, cycling females and ovariectomized females. However, normal males display significantly more PS than cycling females during both daytime and nighttime (average of all estrus stages). On the other hand, while ovariectomy has no visible effect on daytime sleep--the sexual dimorphism of PS is unchanged by ovariectomy--during nighttime, ovariectomy produces a selective increase of PS, eliminating the sex difference during the night. In sum, normal cycling females show no change in daytime sleep patterns across the estrus cycle, but have significantly less PS during proestrus nights than during metestrus and diestrus nights. The results indicate that the sex difference in nighttime PS is due to the suppression of PS by ovarian hormones during proestrus and, to a less extent, estrus nights. The sex difference in daytime PS, on the other hand, appears to be independent of circulating ovarian hormones.

Animals↗
PubMed1996

Determination of 4-(4-chlorophenyl)-4-hydroxypiperidine, a metabolite of haloperidol, by gas chromatography with electron-capture detection.

An electron-capture gas chromatographic procedure was developed for the analysis of 4-(4-chlorophenyl)-4-hydroxypiperidine (CPHP), a metabolite of haloperidol. The assay involved basic extraction of this metabolite from the biological samples, followed by back-extraction with HCl. After basification of the acid phase, extractive derivatization with pentafluorobenzoyl chloride in toluene was conducted. The pentafluorobenzoyl derivative was quantified on a gas chromatograph equipped with a fused-silica capillary column, an electron-capture detector and a printer-integrator. N-(3-Trifluoromethylphenyl)piperazine was carried through the procedure as an internal standard and calibration curves were determined for each assay run. The procedure was demonstrated to be linear and reproducible and was utilized to detect and quantify CPHP in urine, plasma, brain and liver samples from rats treated with haloperidol. The structure of the derivatized metabolite was confirmed by gas chromatography-mass spectrometry.

Animals↗
PubMed1996

Stimulation of new bone formation by direct transfer of osteogenic plasmid genes.

Degradable matrices containing expression plasmid DNA [gene-activated matrices (GAMs)] were implanted into segmental gaps created in the adult rat femur. Implantation of GAMs containing beta-galactosidase or luciferase plasmids led to DNA uptake and functional enzyme expression by repair cells (granulation tissue) growing into the gap. Implantation of a GAM containing either a bone morphogenetic protein-4 plasmid or a plasmid coding for a fragment of parathyroid hormone (amino acids 1-34) resulted in a biological response of new bone filling the gap. Finally, implantation of a two-plasmid GAM encoding bone morphogenetic protein-4 and the parathyroid hormone fragment, which act synergistically in vitro, caused new bone to form faster than with either factor alone. These studies demonstrate for the first time that repair cells (fibroblasts) in bone can be genetically manipulated in vivo. While serving as a useful tool to study the biology of repair fibroblasts and the wound healing response, the GAM technology may also have wide therapeutic utility.

Animals↗
PubMed1996

Changes in cervical canal spinal volume during in vitro flexion-extension.

STUDY DESIGN: Quasistatic flexion and extension loads were applied in vitro to lower cervical spines. The flexion-extension motion produced was checked for physiologic relevance. OBJECTIVES: To examine the changes in the volume of the cervical spinal canal in flexion-extension motion. SUMMARY OF BACKGROUND DATA: Many papers have been published concerning the cervical canal volume as inferred from standard lateral radiographs. This study compares the inferred (radiographic) volumes and their changes to the physical changes within the spinal canal. METHODS: The lower cervical spines (C2-C7) from 10 cadavers were subject to stepwise flexion and extension in a purpose-built rig. Before this testing, the spinal cord was removed from the canal space of each specimen and replaced by a thin latex tube stoppered and secured at the opening of the canal (at C2) so that the volume of liquid displaced from the tube could be measured. This was done at each loading stage by means of a graduated glass column, and a radiograph of the spine was also taken to allow angular and displacement readings to be taken from C2 to C7. RESULTS: The average recorded change in volume of the spinal canal with flexion-extension motion was 1.9 ml, and showed a significant linear correlation with the dynamic canal width (r = 0.868, P < 0.05) and also with the total angle of flexion or extension (r = 0.979, P < 0.005). The volume of liquid displaced from the canal in lateral bending was much lower than that in flexion-extension motion, and only amounted to about 0.2 ml. The angular ranges of motion produced at each level were compared to previous results obtained in vivo, and no significant differences between the angular displacements found in vivo and in vitro under this experimental arrangement were seen. CONCLUSIONS: The loading regime described in this study causes angular displacements similar to those in vivo, and on this basis is a physiologically relevant loading pattern. The change in the volume of the spinal canal between C2 and C7 shows linear relationships with the angle of flexion and the dynamic canal width.

Adult↗
PubMed1996

Pilomatricoma-like endometrioid adenosquamous carcinoma of the ovary with neuroendocrine differentiation.

A case of high-grade endometrioid adenosquamous carcinoma of the ovary showing pilomatricoma-like areas and neuroendocrine differentiation is presented. The pilomatricoma-like areas were strongly positive for cytokeratin and vimentin, whereas the poorly differentiated areas of the tumor were positive for cytokeratin, synaptophysin, and neuron-specific enolase. Review of the literature did not show any published report of adenosquamous carcinoma with pilomatricoma-like areas either in the ovary or in the uterus.

Carcinoma, Adenosquamous↗
PubMed1996

Supernatant rescue assay vs. polymerase chain reaction for detection of wild type adenovirus-contaminating recombinant adenovirus stocks.

The certification of recombinant adenoviruses prepared for clinical use requires the exclusion of contaminating, replication-competent adenovirus (wild type virus). Polymerase chain reaction (PCR)-based detection assays have been developed that detect the presence of viral sequences present only in wild type adenoviruses. As an alternative, this report describes a novel bioassay, designated the 'supernatant rescue assay', that detected minimal amounts of wild type virus mixed with high numbers of recombinant adenoviruses. This assay is based on the observation that minimal numbers of wild type adenovirus can be rescued from the supernatants of cells exposed to high multiplicities of infection (mois) of recombinant virus mixed with a known, minimal number of wild type virions. This assay was highly reproducible and routinely detected the presence of a single wild type virus mixed within 10(9) recombinant viruses. Under the experimental conditions employed, the supernatant rescue assay was significantly more sensitive than all three different PCR-detection assays.

Adenoviruses, Human↗
PubMed1996

Peripheral-nerve allotransplantation in rats immunosuppressed with transient or long-term FK-506.

The purpose of this study was to assess regeneration across peripheral-nerve allografts by electro-physiologic methods, in rats receiving transient or long-term immunosuppression with FK-506. Lewis rats (LEW, RT1(1)) were recipients of sciatic nerve isografts or allografts from donor LEW or ACI (RT1a) rats, respectively. This latter donor-recipient inbred combination represents a major histoincompatible mismatch. The sciatic nerve was exposed through a gluteal muscle-splitting incision. A 2.0-cm segment of nerve was excised and a 2.5-cm graft sutured into the gap in epineural fashion. Seven groups (n = 8 each) included: Group 1--isograft control (LEW/LEW): Group 2--allograft control (LEW/ACI); Group 3--allografts receiving cyclosporin A (CsA) (10 mg/kg BW/day) subcutaneously for 2 weeks; Group 4--CsA for 2 weeks then biweekly subcutaneously; Group 5--FK-506 (10 mg/kg BW) intramuscularly by single injection; Group 6--FK-506 (1.0 mg/kg BW/day) for 2 weeks then biweekly intramuscularly; and Group 7--FK-506 for 2 weeks then biweekly intramuscularly. At 7 months, conduction velocities were determined and statistical analysis was performed. Excellent neural regeneration was observed in the isograft group (61.6 m/s), the allograft groups receiving long-term immunosuppression with either CsA (62.3 m/s) or FK-506 (61.7 m/s), and the transient FK-506 group (60.2 m/s). The transient CsA group (41.9 m/s), the allograft control group (53.4 m/s), and the single-dose FK-506 group (40.8 m/s) demonstrated significantly poorer results. Transient immunosuppression with FK-506 allowed for the restoration of anatomic and physiologic function of a peripheral-nerve allograft in inbred rats.

Animals↗
PubMed1996

Nuclear proteins of quiescent Xenopus laevis cells inhibit DNA replication in intact and permeabilized nuclei.

Quiescent cells from adult vertebrate liver and contact-inhibited or serum-deprived tissue cultures are active metabolically but do not carry out nuclear DNA replication and cell division. Replication of intact nuclei isolated from either quiescent Xenopus liver or cultured Xenopus A6 cells in quiescence was barely detectable in interphase extracts of Xenopus laevis eggs, although Xenopus sperm chromatin was replicated with approximately 100% efficiency in the same extracts. Permeabilization of nuclei from quiescent Xenopus liver or cultured Xenopus epithelial A6 cells did not facilitate efficient replication in egg extracts. Moreover, replication of Xenopus sperm chromatin in egg extracts was strongly inhibited by a soluble extract of isolated Xenopus liver nuclei; in contrast, complementary-strand synthesis on single-stranded DNA templates in egg extracts was not affected. Inhibition was specific to endogenous molecules localized preferentially in quiescent as opposed to proliferating cell nuclei, and was not due to suppression of cdk2 kinase activity. Extracts of Xenopus liver nuclei also inhibited growth of sperm nuclei formed in egg extracts. However, the rate and extent of decondensation of sperm chromatin in egg extracts were not affected. The formation of prereplication centers detected by anti-RP-A antibody was not affected by extracts of liver nuclei, but formation of active replication foci was blocked by the same extracts. Inhibition of DNA replication was alleviated when liver nuclear extracts were added to metaphase egg extracts before or immediately after Ca++ ion-induced transition to interphase. A plausible interpretation of our data is that endogenous inhibitors of DNA replication play an important role in establishing and maintaining a quiescent state in Xenopus cells, both in vivo and in cultured cells, perhaps by negatively regulating positive modulators of the replication machinery.

Animals↗
PubMed1996

Cancer mortality of Chinese in New York City 1988-1992.

BACKGROUND: This study examines cancer mortality among Chinese migrants in New York City, and compares it with that of residents of China as well as New York City whites. METHOD: Mortality records for 1988-1992 from the New York City Department of Health, and the 1990 US census data for New York City were used for the analysis. Age-specific deaths and the population of urban China reported by the World Health Organization were also used for comparison. Age-adjusted death rates by gender for Chinese and whites in New York City, as well as for Chinese in China were computed using the world standard population. RESULTS: New York Chinese had lower mortality rates for all causes, total cancer, oesophageal and lung cancer deaths than did either New York whites or Chinese in China in both genders. However, they had lower death rates than New York whites, but similar to those in China, for colon cancer in both genders, and breast cancer in females. By contrast, New York Chinese had higher death rates for nasopharyngeal cancer than either New York City whites or Chinese in China. Stomach and liver cancer death rates in New York Chinese fell between those in China and New York City whites. CONCLUSIONS: Cancer mortality rates among Chinese migrants in New York City being the lowest for total cancer and some types of cancers, did not follow the usual pattern of migrants (an intermediate position between rates of native New Yorkers and Chinese in homeland China). However, substantial variations in certain cancer-specific mortality by geography were observed.

Adult↗
PubMed1996

An interleukin-1 receptor fragment inhibits spontaneous sleep and muramyl dipeptide-induced sleep in rabbits.

Interleukin-1 (IL-1) is hypothesized to be involved in physiological sleep regulation and in sleep responses occurring during infectious disease. If this hypothesis is correct, then inhibition of endogenous IL-1 should reduce both normal sleep and N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP)-induced sleep. MDP is a somnogenic substance derived from bacterial cell walls. We report here the effects of a synthetic IL-1 receptor fragment corresponding to amino acid residues 86-95 of the human type I IL-1 receptor (IL-1RF) on spontaneous sleep and IL-1 beta- and MDP-induced sleep and fever in rabbits. Two doses of the IL-1RF (25 and 50 micrograms) were injected into normal rabbits intracerebroventricularly (icv). Both doses significantly decreased spontaneous non-rapid eye movement sleep (NREMS) across a 22-h recording period. Pretreatment of rabbits with 25 micrograms of IL-1RF blocked the somnogenic actions of 10 ng icv IL-1. Similarly, central pretreatment of animals with 25 micrograms IL-1RF significantly attenuated the NREMS-promoting and REMS-suppressive actions of 150 pmol MDP injected centrally. The increase in NREMS and decrease in REMS induced by systemic injection of 12.5 micrograms/kg MDP were also significantly suppressed by central administration of 50 micrograms IL-1RF. In contrast, the febrile response induced by either intracerebroventricularly or intravenously injected MDP were not significantly affected by IL-1RF. These results support the hypothesis that endogenous, brain-derived IL-1 contributes to the maintenance of normal sleep and may mediate sleep responses to systemic as well as central bacterial infections.

Acetylmuramyl-Alanyl-Isoglutamine↗