Biomedical subjects

D Hu

Publications and source records attributed to D Hu.

At least 91 records · Page 5Linked to original sources

PubMed1999

Use of the Semmes-Weinstein monofilament in the strong heart study. Risk factors for clinical neuropathy.

OBJECTIVE: We used the Semmes-Weinstein 5.07 monofilament to assess the prevalence of foot insensitivity and its relationship to potential risk factors. RESEARCH DESIGN AND METHODS: There were 3,638 American Indian participants from Arizona, North and South Dakota, and Oklahoma who attended a study clinic on two occasions: baseline and follow-up, 4 years later. Oral glucose tolerance tests were performed at the visits for those who had not previously been diagnosed as having diabetes. A total of 2,051 participants were diagnosed with diabetes before the study or at the subsequent study visits. At the follow-up visit, participants were tested for their ability to sense the 5.07 (10 g) monofilament at 10 sites of the foot. The prevalence of foot insensitivity was ascertained, and its relation to characteristics of participants was assessed in both univariate and logistic regression analyses. RESULTS: Diabetic participants had a much higher prevalence of foot insensitivity (defined as greater than or equal to five incorrect responses) than nondiabetic participants (14 vs. 5%, respectively). However, marked foot insensitivity was uncommon within the first few years of diagnosis of diabetes. Among the diabetic participants, those diagnosed before study entry had the highest prevalence of foot insensitivity. The prevalence of foot insensitivity was highest in the Arizona Indians (22 vs. 9% in the Dakotas and 8% in Oklahoma). In a logistic regression analysis, foot insensitivity was significantly and independently related to center (Arizona versus others), age, duration of diabetes, and height. CONCLUSIONS: Marked foot insensitivity is prevalent in the diabetic American Indian population, especially in Indians in Arizona; however, this insensitivity is apparently uncommon for several years after the diagnosis of diabetes. The data show that Indians with diabetes are particularly vulnerable to the risk of foot ulceration and that the diagnostic screening of diabetes may lead to better prevention of sensory neuropathy and subsequent foot ulceration.

Age Factors↗

PubMed1999

Glycemic control in diabetic American Indians. Longitudinal data from the Strong Heart Study.

OBJECTIVE: To describe glycemic control and identify correlates of elevated HbA1c levels in diabetic American Indians participating in the Strong Heart Study, which is a longitudinal study of cardiovascular disease in American Indians in Arizona, Oklahoma, South Dakota, and North Dakota. RESEARCH DESIGN AND METHODS: This analysis is based on data from the baseline (1989-1992) and first follow-up (1994-1995) examinations of the Strong Heart Study. The 1,581 diabetic participants included in this analysis were aged 45-74 years at baseline, were diagnosed with diabetes before and at baseline, and had their HbA1c levels measured at follow-up. HbA1c was used as the index of glycemic control. Characteristics that may affect glycemic control were evaluated for cross-sectional and longitudinal relationships by analysis of covariance and multiple regression. RESULTS: There was no significant difference between median HbA1c at baseline (8.4%) and at follow-up (8.5%). Sex, age (inversely), and insulin and oral hypoglycemic agent therapy were significantly related to HbA1c levels in both the cross-sectional and longitudinal analyses. Current smoking, prior use of alcohol, and duration of diabetes were significant only for the cross-sectional data. Baseline HbA1c significantly and positively predicted HbA1c levels at follow-up. Comparison of HbA1c by therapy type shows that insulin therapy produced a significant decrease in HbA1c between the baseline and follow-up examinations. CONCLUSIONS: Glycemic control was poor among diabetic American Indians participating in the Strong Heart Study. Women, patients taking insulin or oral hypoglycemic agents, and younger individuals had the worst control of all the participants. Baseline HbA1c, and weight loss predicted worsening of control, whereas insulin therapy predicted improvement in control. Additional therapies and/or approaches are needed to improve glycemic control in this population.

Administration, Oral↗

PubMed1999

The effect of mitomycin C after long-term storage on human Tenon's fibroblast proliferation.

PURPOSE: To investigate the effect of mitomycin C (MMC) after long-term storage on proliferation of human Tenon's fibroblasts in vitro. METHODS: Human Tenon's fibroblasts in tissue culture were exposed for 5 minutes to MMC (0.4 mg/mL) that was either freshly prepared or had been stored for as long as 18 months at either 4 degrees C or -20 degrees C. The MTT colorimetric assay was used to determine the inhibition of proliferation as measured indirectly by mitochondrial activity. RESULTS: The inhibition rate was 88% using fresh MMC, and declined to a mean of 73% when using MMC that had been stored for as long as 18 months at 4 degrees C; this decrease was not statistically significant. The mean inhibition for MMC stored at -20 degrees C was 68%, and this was significantly less than inhibition with fresh MMC. Inhibition did not vary significantly with MMC after different storage times. CONCLUSION: Mitomycin C continues to have strong in vitro antiproliferative effects when stored for as long as 18 months at 4 degrees C or -20 degrees C. A significant decline in potency compared with fresh MMC occurs when MMC is stored at -20 degrees C.

Cell Division↗

PubMed1999

[The origin of calcitonin gene-related peptide (CGRP) in burned skin of rats].

OBJECTIVE: To investigate the origin of calcitonin gene related-peptide (CGRP) in skin burn wound. METHODS: Immunohistochemistry technique was used to determine change in distributive density in CGRP-containing nerve fibers in the wound, wound margin, remote intact skin of rats during the first 96 hours postburn. RESULTS: It was shown that the distributive density of CGRP-containing nerve fibers in all areas decreased at 15 min postburn, but the density recovered earlier in wound margins compared to other sites. In addition, CGRP immunoreactive positive cells, which emigrated from blood vessel in dermis underneath the wound and wound margin, were related to CGRP-containing nerve fibers at 12 hours. Stronger staining intensity to CGRP was observed in those cells and they disintegrated and released CGRP immunoreactive materials into the dermis at 24 hours. Thereafter, those cells disappeared. CONCLUSION: CGRP not only is released from cutaneous nerve, but also is synthesized and released by immune cells in response to burns.

Animals↗

PubMed1999

[Research on immunological activity of non-immunological cells of decidua in normal early pregnancy].

OBJECTIVES: To investigate the immunological activity of non-immunological cells of decidua in normal early pregnancy. METHODS: Harvest the supernatant from cultured non-immunological cells of decidua. Inspect the effects of the supernatant on transforming function of T cells, killing activity of natural killer cells, the IgG secretion of B cells and the interleukin-2 (IL-2) secretion by lymphocytes of human peripheral blood by radioimmunological assay (RIA). RESULTS: The supernatant of the cultured non-immunological cells of decidua can inhibit the immunological function of T cells, natural killer cells and B cells to different extents, their maximum inhibiting ratio were 22.7%, 52.3% and 14.8% respectively, but there is no significant effect on the IL-2 secretion by lymphocytes. CONCLUSIONS: The non-immunological cells of decidua in normal early pregnancy have immunological inhibiting function, which might contribute to prevent fetus from being expelled by maternal immunological system.

Cells, Cultured↗

PubMed1999

[The changes of calcitonin gene-related peptide (CGRP)-containing nerve fibers in adrenal gland of burned rats].

OBJECTIVE: To investigate the changes in calcitonin gene-related peptide(CGRP) within the adrenal glands medulla and cortex of the rat during early post burn period and the effect of CGRP on function of adrenal gland of burned rats. METHODS: The rats were randomly divided into two groups: control and burned. The distribution density of CGRP containing nerve fibers and cells in medulla of adrenal gland were determined at different timepoints post burn. RESULTS: 1. The CGRP-containing nerve fibers were distributed in capsule, cortex and medulla. CGRP-containing nerve fibers were associated with CGRP immunoreactive cell in medulla of adrenal glands. 2. Distribution density of CGRP-containing nerve fiber was decreased, but distribution density of CGRP-containing cells in medulla increased. CONCLUSION: CGRP may affect function of the adrenal gland of burned rats.

Adrenal Cortex↗

PubMed1999

[A randomized controlled clinical study of sparfloxacin versus ofloxacin in the treatment of bacterial infections].

OBJECTIVE: To evaluate the efficacy and safety of sparfloxacin in the treatment of bacterial infections. METHODS: A randomized controlled multi-centre clinical trial was conducted. Ofloxacin used as the control drug. A total of 212 patients entered the study, with 106 in the sparfloxacin group and the remaining 106 in the ofloxacin group. Both compounds were given by oral administration. RESULTS: The cure rate of sparfloxacin and ofloxacin was 74.5% and 69.8% respectively and the overall efficacy rate was 91.5% and 88.7% respectively. The bacterial clearance rate was 90.7% in the sparfloxacin group and 90.8% in the ofloxacin group. The adverse drug reaction rate of sparfloxacin and ofloxacin was 9.43% and 8.49% respectively. There was no statistical significant difference between the two groups for the above results. The results of in vitro activity of sparfloxacin as compared with other 5 antibacterial agents showed that sparfloxacin had good activity against many Gram-negative organisms and was similar to those of ofloxacin. The activity against Gram-positive organisms (MIC(90) <or= 0.25 mg/L) was generally higher than that of ofloxacin. CONCLUSION: Sparfloxacin is a highly effective and safe broad-spectrum antibacterial agent for the treatment of bacterial infections. It is also effective in the treatment of infections caused by Gram-positive organisms.

Adolescent↗

PubMed1999

[No arresting aorta undergoing open heart surgery with CPB through a right anterolateral thoracotomy].

We performed operation of CPB without arresting aorta on 57 cardiac patients through a right anterolateral thoracotomy. Results showed: except that one case of ASD required a 2nd time thoracotomy to hemostasis for a lot of drainage, another case of residual shunt postoperation of TOF was not satisfactory in repair, the others are perfect. There were no operative or hospitalized mortality, no incision infection. It has also solve the psychological distress of female patients provoking by midline showy scar of median sternotomy, so it has acquire a good surgical cosmetic effect.

Adolescent↗

PubMed1999

[Studies on quality standard of Fructus Amomi].

OBJECTIVE: To study the quality standard of different parts and species of Fructus Amomi from different producing. METHOD: GC method, ash determination and water determination. RESULT: The contents of bornyl acetate in different parts and species of Fructus Amomi from different producing areas were obviously different, but the traditional curative effects remained unchanged. The standards for the total ash content, acid-insoluble ash content and water content in Fructus Amomi have been set up. CONCLUSION: Bornyl acetate with a definite content limit should be chosen as the index in studying the quality standard of Fructus Amomi.

Amomum↗

PubMed1999

[The efficacy on natural extrinsic stain of Colgate whitening dentifrice--eight-week study].

OBJECTIVE: To assess the effect on natural extrinsic dental stain by use of a dentifrice containing 1% tetrasodium polyphosphate (TSPP), 7% sodium tripolyphosphate (STPP), 0.243% sodium fluoride and 10% high cleaning silica (HCS) over an eight-week period was compared to a sodium fluoride/silica placebo dentifrice without stain removal ingredients. METHODS: Ninety one subjects were selected and stratified into two balanced groups randomly assigned to use the test dentifrice or the placebo dentifrice. The two groups were well balanced with regard to their mean baseline stain index scores, gender and tobacco habits. Subjects were instructed to brush their teeth twice daily (morning and evening) for one minute with their assigned dentifrice and a commercially available soft bristled toothbrush. Extrinsic dental stain examinations, which included mean stain area and mean stain intensity, were conducted at baseline, four and eight weeks. The same dental examiner conducted examinations on the subjects at each examination. RESULTS: After eight-week use of their assigned products, those subjects in the TSPP/STPP/HCS dentifrice group demonstrated a statistically significant (P = 0.0001) stain reduction of 37.1%, as compared to the fluoride placebo dentifrice group without stain removal ingredients. CONCLUSION: The use of a dentifrice containing 1% tetrasodium polyphosphate, 7% sodium tripolyphosphate, 0.243% sodium fluoride and 10% high cleaning silica is effective in reducing natural extrinsic dental stain, when compared to a placebo fluoride dentifrice.

Adolescent↗

PubMed1999

[Atraumatic restorative treatment fillings and fissure sealants in permanent teeth--a 2-year study].

OBJECTIVE: To study the feasibility of providing Atraumatic Restorative Treatment (ART) in schools and in rural areas in China, and to evaluate the acceptance and effectiveness of the treatment. METHODS: The study was conducted among 272 grade one students chosen from four different secondary schools in Deyang of Sichuan Province, China. The mean age of the subjects was 12.5 years. 107 boys and 165 girls were found at the baseline examination to have teeth that were suitable for receiving ART fillings or sealants. The treatments were performed within a month using the glass ionomer Ketac-Molar manufactured by ESPE. Evaluation was carried out at 3 months, one year and two years after treatment. RESULTS: ART fillings were placed in 295 permanent teeth, and the 1-year and 2-year success rates were 95.7% and 91.1% respectively. ART sealants were placed in another 191 permanent teeth, and the 3-month, 1-year and 2-year success rates were 95.2%, 89.1% and 78.8% respectively. The incidence of recurrent caries was very low after two years, which were 2.1% and 0.6% for the fillings and sealants respectively. ART was accepted by the majority of the students. CONCLUSION: ART is a simple, acceptable technique, and is suitable for widespread adoption in China.

Adolescent↗

PubMed1998

Identification of Lys-403 in the PI-SceI homing endonuclease as part of a symmetric catalytic center.

Superposition of the PI-SceI and I-CreI homing endonuclease three-dimensional x-ray structures indicates general similarity between the I-CreI homodimer and the PI-SceI endonuclease domain. Saddle-shaped structures are present in each protein that are proposed to bind DNA. At the putative endonucleolytic active sites, the superposition reveals that two lysine (Lys-301 and Lys-403 in PI-SceI and Lys-98 and Lys-98' in I-CreI) and two aspartic acid residues (Asp-218 and Asp-326 in PI-SceI and Asp-20 and Asp-20' in I-CreI) are related by 2-fold symmetry. The critical role of Lys-301, Asp-218, and Asp-326 in the PI-SceI reaction pathway was reported previously. Here, we demonstrate the significance of the active-site symmetry by showing that alanine substitution at Lys-403 reduces cleavage activity by greater than 50-fold but has little effect on the DNA binding activity of the mutant enzyme. Substitution of Lys-403 with arginine, which maintains the positive charge, has only a modest effect on activity. Interestingly, even though the Lys-301 and Lys-403 residues display pseudosymmetry, PI-SceI mutant proteins with substitutions at these positions have different behaviors. The presence of similar basic and acidic residues in many LAGLIDADG homing endonucleases suggests that these enzymes use a common reaction mechanism to cleave double-stranded DNA.

Amino Acid Sequence↗

PubMed1998

Common molecular pathways in skeletal morphogenesis and repair.

The formation of bone is a continual process in vertebrate development, initiated during fetal development and persisting in adulthood in the form of remodeling and repair. The remarkable capacity of skeletal tissues to regenerate has led to the hypothesis that the molecular signaling pathways regulating skeletogenesis are shared during fetal development and adult wound healing. A number of key regulatory pathways that are required for endochondral ossification during fetal development are described, and their reintroduction in fracture repair demonstrated. Secreted proteins such as Sonic and Indian hedgehog exert their effect on pattern formation and chondrogenesis in the appendicular skeleton, partly through regulation of molecules such as bone morphogenic proteins (Bmps) and parathyroid hormone-related peptide (PTHrP). Once chondrocytes have matured and hypertrophied, they undergo apoptosis and are replaced by bone; the transcription factor Cbfal plays a critical role in this process of chondrocyte differentiation and ossification. Analyses of the expression patterns of these genes during fracture healing strongly suggest that they play equivalent roles in adult wound repair. Knowledge acquired through the study of fetal skeletogenesis will undoubtedly contribute to an understanding of fracture repair, and subsequently guide the development of biologically based therapeutic interventions.

Animals↗

PubMed1998

Inhibition of hGrb10 binding to the insulin receptor by functional domain-mediated oligomerization.

hGrb10 is a newly identified Src homology 2 (SH2) and pleckstrin homology (PH) domain-containing protein that binds to autophosphorylated receptor tyrosine kinases, including the insulin and insulin-like growth factor receptors. To identify potential downstream proteins that interact with hGrb10, we screened a yeast two-hybrid cDNA library using the full-length hGrb10gamma as bait. A fragment of hGrb10, which included the IPS (insert between the PH and SH2 domain) and the SH2 domains, was found to bind with high affinity to the full-length protein. The interaction between the IPS/SH2 domain and the full-length hGrb10 was further confirmed by in vitro glutathione S-transferase fusion protein binding studies. Gel filtration assays showed that hGrb10 underwent tetramerization in mammalian cells. The interaction involved at least two functional domains, the IPS/SH2 region and the PH domain, both of which interacted with the NH2-terminal amino acid sequence of hGrb10gamma (hGrb10gamma DeltaC, residues 4-414). Competition studies showed that hGrb10gamma DeltaC inhibited the binding of hGrb10 to the tyrosine-phosphorylated insulin receptor, suggesting that this region may play a regulatory role in hGrb10/insulin receptor interaction. We present a model for hGrb10 tetramerization and its potential role in receptor tyrosine kinase signal transduction.

Animals↗

PubMed1998

Alleviation of x-irradiation-based deficit in memory-based learning by D-amphetamine: suggestions for attention deficit-hyperactivity disorder.

Selective exposure to x-irradiation during infancy, from postnatal days (PND) 2-11 in the rat, results in severe hippocampal granule cell hypoplasia. Preweanling (PND 17-18) rats, which suffer such hippocampal granule-cell agenesis, show deficits in patterned single alternation (PSA), a form of memory-based learning. Deficits in short-term memory along with increased arousal have been suggested as characteristic of children diagnosed with attention deficit-hyperactivity disorder (ADHD). We report here on the ameliorating effects of D-amphetamine, a drug commonly used in the treatment of ADHD, before Ritalin, on PSA, after infantile (PND 2-15) exposure to x-irradiation. After i.p. injections of 0.3 mg/kg D-amphetamine, the onset and magnitude of the PSA memory-based discrimination in the x-irradiated preweanling rats was restored to about the level of controls. These results, showing alleviation of x-irradiation-related deficits in short-term memory by D-amphetamine injections, along with our earlier and present results, showing substantial deficits after x-irradiation alone, encourage the hypothesis that hippocampal granule-cell hypoplasia, which would occur in humans prenatally and is Altman's model of "minimal brain dysfunction" [Altman, J. (1986) in Learning Disabilities and Prenatal Risk, ed. Lewis, M. (Univ. of Illinois Press, Urbana), pp. 241-304], may be a factor in at least some forms of ADHD and may provide a basis for an animal model of the disease.

Animals↗

PubMed1998

DNA vaccines encoding full-length or truncated Neu induce protective immunity against Neu-expressing mammary tumors.

We generated DNA expression vectors encoding the full-length neu cDNA (designated pNeuN), the neu extracellular domain (pNeuE), or the neu extracellular and transmembrane domains (pNeuTM). The 293 cells transfected with pNeuN or pNeuTM expressed the neu extracellular domain on the surface membrane, whereas 293 cells transfected with pNeuE secreted the extracellular domain of neu into the culture supernatant. We examined whether i.m. injection of either of these plasmids could induce protective immunity in FVB/N mice against the adoptive transfer of Tgl-1 cells, a neu-expressing tumor cell line generated from a mouse mammary tumor that spontaneously arose in a FVB/N neu-transgenic mouse. The i.m. injection of pNeuTM or pNeuE, and to a lesser extent pNeuN, induced protective immunity against a subsequent challenge with Tgl-1 cells in FVB/N mice. In addition, the coinjection of a plasmid encoding interleukin-2 (designated pIL-2) augmented the efficacy of each of the pNeu plasmids for inducing protective immunity. The plasmid pNeuTM seemed to be the most effective for inducing anti-neu antibodies. However, the generation of detectable anti-neu antibodies in response to any one of these pNeu plasmids was not enhanced by coinjection of pIL-2 and was not required for protective immunity against Tgl-1 cells. These studies demonstrate that DNA expression vectors encoding soluble or membrane-bound forms of neu lacking the cytoplasmic kinase domain can be effective in inducing protective antitumor immunity.

Adoptive Transfer↗

PubMed1998

The C. reinhardtii CF1 with the mutation betaT168S has high ATPase activity.

We have generated the mutation T168S in the beta subunit of the chloroplast ATP synthase complex of Chlamydomonas reinhardtii by site directed mutagenesis and chloroplast transformation. CF1 and the alpha3beta3gamma complex of this mutant strain were isolated and their enzymatic activities were characterized and compared to those of the corresponding wild type complexes. Without activation the mutant CF1 exhibits MgATPase activity with at least 10 times higher rates than the wild type enzyme. The MgATPase activity could be stimulated to some extent by methanol, but less by ethanol and octylglucoside. The alpha3beta3gamma complex had an even higher MgATPase activity, which was only slightly enhanced by ethanol or methanol. The ATPase activities of the mutant complexes, like those of the wild type complexes, displayed a sharp concentration optimum for Mg2+. Free ADP inhibited neither the mutant nor the wild type ATPase significantly. Azide, which strongly inhibited the ATPase activity of the wild type enzyme, inhibited the mutant enzyme only at an about 30 times higher concentration suggesting that the mutation T168S prevents trapping of a tightly bound MgADP by a catalytic site that regulates chloroplast ATPase activity. The mutant cells grew photoautotrophically at a growth rate of about 50%. Similar to the wild type the cells survived on minimal medium in the dark. Under heterotrophic conditions with acetate as energy and carbon source the mutant cells grew much faster than the wild type cells, but the chlorophyll content per cell decreased dramatically.

Animals↗

PubMed1998

An evaluation of linear model analysis techniques for processing images of microcirculation activity.

Sequences of images of the cortical surface can be processed to reveal information about the cortical microcirculation, regional cerebral blood flow (rCBF), and changes induced by neuronal activity. This study examined the use of different analysis methodologies on intrinsic optical images taken from rat sensory motor cortex and testes. Generalized linear model (GLM) analysis was used and compared with standard signal processing methods including principal component analysis. The GLM method has been used by Friston et al. (1994, Hum. Brain Map., 1: 214-220) in the analysis of functional magnetic resonance imagery to identify regions of focal activity. We investigated the use of this method to analyze video image data of the modulation of rCBF from rat cortex. The results revealed spatiotemporal variations in rCBF in response to stimulation within local regions of cortex. The advantage of the GLM method is that it augments ordinary signal processing methods with an estimate of statistical reliability. The use of different wavelengths of illumination reveals spatial structures with different temporal relationships. In image time series data collected under green and red illumination a phase difference was found in the low frequency approximately 0.1 Hz vasomotion oscillation. This phase difference occurred in data from both cortex and testes. A possible explanation of these differences is that the spectral absorption characteristics of the tissue reflect changes in the volume proportions of the different hemoglobin derivatives in interacting with the modulation of the volume of blood. It is suggested that the combination of these effects produces the phase differences we detect.

Animals↗