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Biomedical subjects

J Chu

Publications and source records attributed to J Chu.

At least 55 records · Page 3Linked to original sources
PubMed2000

Intestinal ischemia and the gut-liver axis: an in vitro model.

BACKGROUND: Sustained intestinal ischemic injury often leads to shock and multiorgan failure, mediated in part by a cytokine cascade. Animal models have also identified a central role of Kupffer cells in amplification of cytokines following intestinal ischemia. To better understand this gut-liver axis, we developed an in vitro model. MATERIALS AND METHODS: Kupffer cells were isolated from rat livers by arabinogalactan gradient ultracentrifugation and adherence purification. Cells were grown in RPMI medium in 5% CO(2). Rat intestinal epithelial cells, IEC-6, were cultured under normoxic or anoxic (90% N(2), 10% CO(2)) conditions for 2, 12, and 24 h. Kupffer cells were then grown in the conditioned medium of the IEC-6 cultures. After 24 h, the medium was replaced with fresh medium. This final Kupffer cell supernatant was tested for tumor necrosis factor alpha and interleukin-6 production by ELISA. Trypan blue exclusion was performed to assess cell viability. RESULTS: Intestinal and Kupffer cells remained viable during the experimental time. Production of both tumor necrosis factor alpha and interleukin-6 by Kupffer cells increased with increasing ischemia time of the intestinal cells. CONCLUSIONS: Consistent with animal studies of intestinal ischemia, this study found an increase in cytokine production by Kupffer cells following hypoxia of intestinal cells. This in vitro model offers a new tool to study the expression of cytokines, proteins, and messengers involved in the cascade of events that follow intestinal ischemia.

Animals↗
PubMed2000

Lysophosphatidic acid stimulates intestinal restitution via cytoskeletal activation and remodeling.

BACKGROUND: The gastrointestinal tract heals superficial wounds by a process of epithelial migration termed restitution. Restitution is an important response for preventing conditions like stress gastritis, ulcer disease, celiac sprue, ischemia-reperfusion injury, bacterial translocation during shock, and inflammatory bowel disease. The purpose of this study was to determine the effect of a platelet product, lysophosphatidic acid (LPA), on intestinal restitution. MATERIALS AND METHODS: IEC-6 cells were used to study the effect of LPA on intracellular calcium mobilization, actin stress fiber formation, and actin and FAK protein levels. An in vitro model of restitution was utilized to determine the LPA-stimulated IEC-6 migration. RESULTS: LPA administration stimulated intracellular calcium mobilization in a dose-dependent fashion with typical peak and plateau phases suggestive of a receptor-mediated response. Actin stress fiber formation occurred within 15 min after LPA treatment and was especially apparent at 2 h. This response was accompanied by higher actin and FAK protein levels. LPA also stimulated IEC-6 migration 3-fold within 24 h. All of these effects were completely inhibited by pertussis toxin. CONCLUSIONS: Exposure of IEC-6 cells to LPA results in significant calcium mobilization and cytoskeletal remodeling within minutes. This activity is accompanied by increased actin and FAK levels. Cellular migration is significantly enhanced by LPA. These responses seem to be due to pertussis-sensitive G-protein-associated receptors. The ability of LPA to potentiate intestinal cell restitution appears, in part, to be mediated by effects on intestinal cell cytoskeletal structure.

Actins↗
PubMed2000

Temperature dependency of quantitative ultrasound.

Quantitative ultrasound (QUS) parameters are temperature dependent. We examined the effect of temperature on QUS using Lunar Achilles+ and Hologic Sahara units. In vivo studies were performed in a cadaveric foot and in 5 volunteers. QUS scans were performed in the cadaveric foot, using both machines, at temperatures ranging from 15 to 40 degrees C. To assess the effect of change in water bath temperature in the Achilles+, independently of foot temperature, 5 volunteers were studied at water temperatures ranging from 10 to 42 degrees C. In the cadaveric foot there were strong negative correlations between temperature and speed of sound (SOS) but a moderately positive correlation between temperature and broadband ultrasound attenuation (BUA). Stiffness and the Quantitative Ultrasound Index (QUI) in the cadaveric foot showed strong negative correlations with temperature, reflecting their high dependence on SOS. In the 5 volunteers, in whom foot temperature was assumed to be constant, there was a small change in Stiffness in the Achilles+, with variation in water temperature. In conclusion, while there are opposite effects of temperature on SOS and BUA in vivo, there is still a significant effect of temperature variation on Stiffness and the QUI. This may have clinical significance in particular subjects. The precision of QUS may be affected by temperature variation of the environment or of the patient's limb. Instruments utilizing a water bath may be able partly to compensate for changes in environmental temperature, but standardization of water bath temperature is crucial to maximize precision.

Body Temperature↗
PubMed2000

Multiple origins of Tibetan Y chromosomes.

The genetic origin of Tibetans was investigated using Y chromosome markers. A total of three populations were studied, two from central Tibet speaking central Tibetan and one from Yunnan speaking Kham. Two dominant paternal lineages (>80%) were identified in all three populations with one possibly from central Asia (YAP+) and the other from east Asia (M122C). We conclude that Tibetan Y chromosomes may have been derived from two different gene pools, given the virtual absence of M122C in central Asia and YAP+ in east Asia, with drift an unlikely mechanism accounting for these observations.

Alu Elements↗
PubMed2000

Control of photon beam dose profiles by localized transverse magnetic fields.

Unlike electron beams, scant attention has been paid in the literature to possible magnetic field effects on therapeutic photon beams. Generally, dose profiles are considered to be fully determined by beam shape, photon spectrum and the substances in the beam path. Here we show that small superconducting magnets can exercise potentially useful control over photon dose profiles. The magnet produces a locally strong transverse field with large gradients and is applied to the tissue surface below which the photon beam is passing. For one practical magnet design, our simulations, which use the EGS-4 Monte Carlo code modified to include magnetic field effects, show significant intensification and shielding effects. In water phantoms, the effects extend to 3-4 cm or more beyond the warm face of the cryostat and greater distances are achieved in phantoms simulating lung (density approximately 0.3). Advances in applying the concept and in superconducting materials and magnet design hold promise for extending these ranges.

Humans↗
PubMed2000

Fluorine-18 FDG dual-head gamma camera coincidence imaging of radiation pneumonitis.

A 69-year-old man with inoperable stage I squamous cell carcinoma of the lung underwent a radical course of radiotherapy combined with platinum-based chemotherapy. Fluorine-18 fluorodeoxyglucose (FDG) imaging with a dual-head coincidence gamma camera system (Co-PET) diagnosed radiation pneumonitis 1 month after completion of radiotherapy, when the clinical and radiographic signs were atypical and more suggestive of carcinomatous lymphangitis. Treatment with oral steroids was begun based on FDG scan findings, with prompt clinical benefit as would be expected for radiation pneumonitis.

Aged↗
PubMed2000

Low plasma thiamine levels in elder patients admitted through the emergency department.

OBJECTIVES: To determine the prevalence of thiamine deficiency in a high-risk group of elder emergency department (ED) patients who reside in nursing homes and need admission to the hospital, and to determine the effect of patients' diets on this prevalence. METHODS: This was an observational pilot study of 75 consecutive ED patients aged 65 years or older who lived in a nursing home and were admitted to the hospital. Plasma thiamine levels were measured by high-pressure liquid chromatography on serum samples collected within 24 hours of hospital admission. Nursing home records were reviewed to determine whether patients received nutritional supplementation or enteral tube feedings. RESULTS: Seventy patients participated and had a mean plasma thiamine level of 27.3 microg/dL (95% CI = 20.2 to 34.4). Fourteen percent (n = 10, 95% CI = 8% to 24%) were thiamine-deficient (<10 microg/dL). Patients not receiving dietary supplements or tube feedings (n = 26) had lower mean thiamine levels (20.3 microg/dL, 95% CI = 12.7 to 27.9) and were thiamine-deficient more often (27%) than patients receiving dietary support (n = 44, 31.5 microg/dL, 95% CI = 24.7 to 38.3, 7% thiamine-deficient). CONCLUSIONS: Elder nursing home patients seen in the ED and admitted to the hospital are frequently thiamine-deficient. Empiric thiamine supplementation is often used in the ED for other high-risk patients, such as alcoholic individuals, and may be appropriate for high-risk elder patients. Further research is needed to determine whether thiamine supplementation in these patients can improve their clinical outcomes.

Age Distribution↗
PubMed2000

Coexpression of the homeobox genes Distal-less and homothorax determines Drosophila antennal identity.

The Distal-less gene is known for its role in proximodistal patterning of Drosophila limbs. However, Distal-less has a second critical function during Drosophila limb development, that of distinguishing the antenna from the leg. The antenna-specifying activity of Distal-less is genetically separable from the proximodistal patterning function in that certain Distal-less allelic combinations exhibit antenna-to-leg transformations without proximodistal truncations. Here, we show that Distal-less acts in parallel with homothorax, a previously identified antennal selector gene, to induce antennal differentiation. While mutations in either Distal-less or homothorax cause antenna-to-leg transformations, neither gene is required for the others expression, and both genes are required for antennal expression of spalt. Coexpression of Distal-less and homothorax activates ectopic spalt expression and can induce the formation of ectopic antennae at novel locations in the body, including the head, the legs, the wings and the genital disc derivatives. Ectopic expression of homothorax alone is insufficient to induce antennal differentiation from most limb fields, including that of the wing. Distal-less therefore is required for more than induction of a proximodistal axis upon which homothorax superimposes antennal identity. Based on their genetic and biochemical properties, we propose that Homothorax and Extradenticle may serve as antenna-specific cofactors for Distal-less.

Animals↗
PubMed2000

Early observations in radiculopathic pain control using electrodiagnostically derived new treatment techniques: automated twitch-obtaining intramuscular stimulation (ATOIMS) and electrical twitch-obtaining intramuscular stimulation (ETOIMS).

OBJECTIVE: To show in a pilot group of patients that electrodiagnostically derived new treatment techniques (automated twitch-obtaining intramuscular stimulation (ATOIMS) and electrical twitch-obtaining intramuscular stimulation (ETOIMS) methods) have a role in the control of radiculopathy related myofascial pain and fibromyalgia. METHOD: Retrospective analysis of six patients treated between 6-96 and 10-98. All received sequential treatments with ETOIMS and combined ATOIMS and ETOIMS of which four began treatments with standard TOIMS (StdTOIMS). The StdTOIMS utilized manual oscillation of a monopolar electromyographic (EMG) pin at tender muscle sites. ETOIMS employed microelectrical stimulation at 2 Hz for two seconds/site. The ATOIMS device automatically inserts and retracts a monopolar EMG pin after oscillating it at 2 Hz for three cycles/two seconds/site. Obtaining forceful muscle twitches were the goals of all three treatments. Treatment included multiple points in bilateral multiple myotomes. Patients received weekly treatments and recorded daily visual analog pain levels. RESULTS: Significant reductions in pain levels occurred with the use of ETOIMS compared to that achieved with StdTOIMS. The combined use of ATOIMS and ETOIMS was more effective in reducing pain than StdTOIMS or ETOIMS only treatments. CONCLUSIONS: Control of radiculopathy related myofascial pain and fibromyalgia using the ETOIMS with ATOIMS methods seem promising. Reduction of mechanical tension through muscle relaxation is the proposed basis for the pain relief. There is a need for prospective studies to document efficacy in myofascial pain control.

Adult↗
PubMed2000

Progress in the molecular genetic research of multinodular goiter.

Multinodular goiter is a worldwide-distributed disease, but yet its pathology and genetic etiology are not clear. At present, most researches have been restrained to traditional epidemiological survey and the disease has been rarely studied at the level of molecular genetics. The pathogenesis of multinodular goiter, as is generally accepted by most researchers, can be attributed to many factors such as hormones, growth factors and the inherent functional heterogeneity of thyroid follicles. Since hormone and iodine metabolization are widely recognized as a major mechanism in determining the formation of multinodular goiter, some reports in literature are mainly focused on such genes that are responsible for hormone synthesis and iodine metabolization. Mapping experimental data were available to support location of multinodular goiter gene(s) onto chromosome 14q by whole genome scanning in a large pedigree analysis. Additional data, particularly those extracted from large scaled marker-assisted mapping experiments, are important so as to confirm the gene location, to improve resolution of the location, and finally to dissect the genes underlying the disease at molecular level.

Chromosome Mapping↗
PubMed2000

[Studies on the polymorphism of MICA gene in four Chinese populations].

OBJECTIVE: To understand with greater clearness the genetic polymorphism of (GCT)n repeat of MHC class I chain-related gene A (MICA)in some Chinese populations and provide preliminary genetic evidence for the independent origin of Chinese Baima Tibetan (BMT). METHODS: ACD-blood or saliva specimens of 411 unrelated individuals from four Chinese populations were collected. A primer pair spanning exon 5 of MICA gene was used to amplify the GCT region. Alleles were detected by PCR and denaturing PAGE. Comparison of the allelic distributions among the four populations was carried out. RESULTS: Five previously reported alleles have been observed in all the four populations, but the allelic distributions are different from one another. The most frequent allele is the A5 in all the four populations (0.325 in BMT, 0.345 in Tibetans, 0.390 in Chengdu Hans and 0.319 in Qiangs). A5.1 allele is the second most frequent allele in Chengdu Hans (0.230) and in Qiangs (0.293), while the second most frequent alleles for BMT and Tibetans are A4 (0.254) and A9 (0.272) respectively. The distribution of alleles in BMT is significantly different from that in the other three populations. CONCLUSION: Alleles of MICA gene exon 5 are conservative in all populations studied so far. The results suggest that genetically BMT might be an independent ethnic population.

Alleles↗
PubMed2000

Twitch-obtaining intramuscular stimulation (TOIMS): long term observations in the management of chronic partial cervical radiculopathy.

PURPOSE: To display the long term observations noted on using Twitch-Obtaining Intramuscular Stimulation (TOIMS) in the management of myofascial pain from chronic partial cervical radiculopathy. METHODS: Included in the study were forty consecutive patients with chronic neck and upper limb pain who failed standard treatments. They received TOIMS during 1/92 through 6/95. Control patients were those who received standard treatments (StdRx) only. TOIMS patients had longer symptom duration and more chronic electromyographic findings at C5 and C7 levels on the symptomatic side than the StdRx patients. Test patients received TOIMS in a bilateral multisegmental, multiradicular distribution on a 1-2 weekly basis for 23.9 +/- 21.5 treatments. The follow-up rate was 82.5% for TOIMS and 35% for StdRx. Follow-up occurred at 28.6 +/- 9.1 months after the last TOIMS treatment and at 32.2 +/- 4.3 months after the initial contact for the StdRx patients. Main outcomes measured were pain reduction and return to work. RESULTS: For those able to be followed 45.5% of the TOIMS patients chose TOIMS as very effective for pain control, whereas only 10% of the StdRx had similar opinions for conventional treatments. More of the TOIMS patients also had lower pain levels and were working compared to StdRx patients. CONCLUSIONS: Observations suggest TOIMS to have potential value in the long-term management of partial cervical radiculopathy related myofascial pain.

Adult↗
PubMed2000

[Effect of 962 capsule on liver peroxidation, thymus and spleen index].

OBJECTIVE: To investigate the effect of 962 capsule, a TCM compound recipe, on liver peroxidation and weight of thymus and spleen (thymus index, spleen index) in aged rats, and observe the anti-oxidation effect and the influence on immunological function in rats. METHODS: Rats were divided into young control, aged model, positive control (piracetam), 962 middle (0.9 g/kg) dose and high dose (1.8 g/kg) groups, and the medicated rats used in each group were aged rats. All tested drugs were administered for 1 month by gastrogavage. The liver peroxidation was determined by thiobarbituric acid method. The thymus index and spleen index were determined by weighing method. RESULTS: Middle and high dose of 962 capsule attenuated liver peroxidation, their liver MDA lowered, increased the thymus index of aged rats. There was no effect on spleen index in all medicated groups. CONCLUSIONS: 962 capsule could reduce liver lipid peroxidation and increase thymus index. It is suggested that 962 capsule might be beneficial in retarding aging process.

Aging↗
PubMed2000

[Application of extracardiac conduit total cavopulmonary anastomosis].

OBJECTIVE: To evaluate the value of application of extracardiac conduit total cavopulmonary anastomosis (TCPA) in complex heart disease. METHODS: From June 1998 to August 1999, 10 patients with functional univentricular complex congenital heart diseases received TCPA. Eight patients were male and 2 female with a mean age of (9.0 +/- 5.6) years (from 2.5 to 21 years) and a mean weight of (25 +/- 14) kg (from 11 to 45 kg). Associated heart anomalies were TGA, PS or ASD. All surgical procedures were performed under general anesthesia and hypothermia. RESULTS: No operative and postoperative deaths and all patients were followed up for 6 - 18 months. All patients were clinically asymptomatic. There was no increase of systemic venous pressure. EKG revealed no arrhythmias. The cardiac function was in NYHA class I-II. CONCLUSIONS: Extracardiac conduit TCPA is a simple procedure and it is superior to others.

Adolescent↗
PubMed2000

[The preliminary study on the gene mutations of sixty patients with G6PD deficiency in Yunnan province].

OBJECTIVE: To analyze the types and distribution of glucose-6-phosphate dehydrogenase (G6PD) gene mutations in Yunnan province. METHODS: By using the natural primers or mis-matched primers mediated polymerase chain reaction (PCR) followed by endonuclease digestion methods, six types of G6PD gene mutations, G1388A, G1376T, C1024T, G392T, C592T and A95G were in sixty patients with G6PD deficiency. RESULT: Six types of mutation were revealed: 28.3% (17 of 60) were G1388A, 11.7% (7 of 60) G1376T, 6.7% (4 of 60) C1024T, 1.7% (1 of 60) G392T, 1.7% (1 of 60) C592T, 1.7% (1 of 60) A95G and 48.3% (29 of 60) unidentified. C592T mutation is the first report in Yunnan people. CONCLUSIONS: The G6PD gene in Yunnan people is heterogeneous. Research of G6PD gene mutation types may provide some useful data for clinical diagnosis and prevention of G6PD deficiency, and for human genetic study.

Amino Acid Substitution↗