Biomedical subjects

R Peng

Publications and source records attributed to R Peng.

At least 37 records · Page 2Linked to original sources

PubMed1999

Endogenous CD8+ T cell expansion during regression of monoclonal EBV-associated posttransplant lymphoproliferative disorder.

There are experimental data which suggest that the primary immune effector cell responsible for maintaining immune surveillance against the outgrowth of EBV-transformed B cells in humans is the CTL, but in vivo proof of this is lacking. In this study we perform a series of cellular and molecular assays to characterize an autologous, endogenous immune response against a transplantation-associated, monoclonal, EBV+ posttransplant lymphoproliferative disorder (PTLD). Following allogeneic bone marrow transplantation, a patient developed a monoclonal PTLD of donor B cell origin. With a decrease in immune suppression, we document the emergence of endogenous, donor-derived CD3+CD8+ CTLs, followed by regression of the PTLD. The TCR Vbeta repertoire went from a polyclonal pattern prior to the development of PTLD to a restricted TCR Vbeta pattern during the outgrowth and regression of PTLD. Donor-derived CD3+CD8+ T lymphocytes displayed MHC class I-restricted cytolytic activity against the autologous EBV+ B cells ex vivo without additional in vitro sensitization. The striking temporal relationship between the endogenous expansion of a TCR Vbeta-restricted, CD3+CD8+ population of MHC class I-restricted CTL, and the regression of an autologous monoclonal PTLD, provides direct evidence in humans that endogenous CD3+CD8+ CTLs can be responsible for effective immune surveillance against malignant transformation of EBV+ B cells.

Adult↗

PubMed1999

[Serum glutathione S-transferase activity as an early marker of thioacetimide-induced acute hepatotoxicity in mice].

The objective of this paper was to evaluate serum glutathione S-transferasethe (GST) in thioacetimide (TAA)-induced hepatotoxicity in mice. The results showed that intraperitoneal injection of TAA (25-100 mg/kg) increased serum GST activity. The activity of GST was dose- and time-related to TAA. There was a good positive correlation between serum GST and serum alanine transaminase(ALT) activities. The content of reduced glutathione(GSH) and activities of GST, glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) were significantly decreased while serum GST activity induced by TAA was high. The results suggested that the reduced hepatic antioxidative function is one of the mechanism of TAA-induced hepatotoxicity, and serum GST activity is a sensitive and early marker in detecting TAA-induced hepatotoxicity.

Alanine Transaminase↗

PubMed1999

Specific interaction of the yeast cis-Golgi syntaxin Sed5p and the coat protein complex II component Sec24p of endoplasmic reticulum-derived transport vesicles.

The generation of transport vesicles at the endoplasmic reticulum (ER) depends on cytosolic proteins, which, in the form of subcomplexes (Sec23p/Sec24p; Sec13p/Sec31p) are recruited to the ER membrane by GTP-bound Sar1p and form the coat protein complex II (COPII). Using affinity chromatography and two-hybrid analyses, we found that the essential COPII component Sec24p, but not Sec23p, binds to the cis-Golgi syntaxin Sed5p. Sec24p/Sed5p interaction in vitro was not dependent on the presence of [Sar1p.GTP]. The binding of Sec24p to Sed5p is specific; none of the other seven yeast syntaxins bound to this COPII component. Whereas the interaction site of Sec23p is within the N-terminal half of the 926-aa-long Sec24p (amino acid residues 56-549), Sed5p binds to the N- and C-terminal halves of the protein. Destruction by mutagenesis of a potential zinc finger within the N-terminal half of Sec24p led to a nonfunctional protein that was still able to bind Sec23p and Sed5p. Sec24p/Sed5p binding might be relevant for cargo selection during transport-vesicle formation and/or for vesicle targeting to the cis-Golgi.

Binding Sites↗

PubMed1999

Identification of human cytomegalovirus variants by analysis of single strand conformation polymorphism and DNA sequencing of the envelope glycoprotein B gene region-distribution frequency in liver transplant recipients.

Single strand conformation polymorphism analysis (SSCP) of PCR-amplified DNA and subsequent DNA sequencing of human cytomegalovirus (HCMV) glycoprotein B (gB) gene were applied to identify known HCMV strains and to detect new virus variants. 61 HCMV PCR positive patients were studied out of a cohort of 410 patients after liver transplantation (LTX). SSCP was able to distinguish between strains Davis, AD169, and Towne, and in addition could identify five new virus variants (Berlin B, C, E, F, and H). Their frequency, gB and gH types were determined. Simultaneous infections with two or three strains or variants, as well as a switch from one virus to another virus were observed during long-term follow-up. No correlation between the occurrence of certain virus strains or gB types and defined clinical manifestations of HCMV infection after LTX was drawn.

Base Sequence↗

PubMed1999

Penetrating injuries to the subclavian and axillary vessels.

BACKGROUND: Subclavian and axillary vascular injuries are notorious for their mortality and their difficult surgical exposure. In the present study we analyze our experience with 79 patients and describe the techniques used for surgical access to these vessels. STUDY DESIGN: Retrospective review of the medical records of all patients with penetrating injuries to the subclavian or axillary vessels who had been admitted to 2 Los Angeles trauma centers during a 4-year, 3-month period. RESULTS: Seventy-nine patients were admitted during the study period January 1993 to March 1997 (58 gunshot injuries, 21 other penetrating injuries). The artery was injured in 59 patients and the vein in 40 (20 patients had both arterial and venous injuries). Eighteen patients (23%) were admitted with no signs of life or were in extremis and underwent an emergency room thoracotomy without any survivors. Fifty-eight patients underwent exploration in the operating room, 1 patient with an arteriovenous subclavian fistula was successfully managed with a radiologically placed endovascular stent, and 2 patients with minimal subclavian artery injuries were managed nonoperatively. Overall mortality was 34.2%. Excluding the ER thoracotomies the overall mortality was 14.8%. The mortality for isolated arterial injuries was 20.5%, for isolated venous injuries 50%, and for both vessels 45.0%. The mortality in venous injuries was significantly higher than in arterial injuries (p < 0.05). The standard clavicular incision provided adequate exposure in 32 (50.0%) of the operating room cases. In the other 50% of operating room cases a combination of a clavicular incision with a median sternotomy or thoracotomy was necessary. Proximal subclavian injuries may be accessed through a clavicular incision combined with a median sternotomy irrespective of left or right site location. CONCLUSIONS: Subclavian and axillary vascular injuries remain lethal. A clavicular incision provides satisfactory surgical exposure in about half the patients. In patients with proximal injuries addition of a median sternotomy provides adequate surgical access in both right and left subclavian vessels.

Adult↗

PubMed1999

Stress experienced by mothers of Malaysian children with mental retardation.

OBJECTIVE: To compare parenting stress among Malaysian mothers of children with mental retardation and a control group, and to determine factors associated with stress. METHODOLOGY: Seventy-five mothers of children with mental retardation aged 4-12 years and 75 controls (those without disabilities who attended the walk-in paediatric clinic) participated in the Parenting Stress Index (PSI). Intelligence quotient (IQ) and Child Behaviour Checklist (CBCL) scores, together with sociodemographic data, were entered into a multiple stepwise regression analysis, using the PSI as the criterion. RESULTS: Mothers of children with mental retardation scored significantly higher than control subjects in both the child-related domain (difference between means 26.1, 95% confidence interval 19.6-32.5) and parent-related domain (difference between means 15.0, 95% confidence interval 7.9-22.1) of the PSI. The total child behaviour scores from the CBCL (P < 0.01), IQ scores (P < 0. 01) and sibship size (P < 0.01) were associated with child-related domain scores. For the parent-related domain, CBCL (P < 0.01) and IQ scores (P = 0.01) remained important factors but Chinese ethnicity (P < 0.01) and maternal unemployment (P < 0.01) were also significant predictors of stress. CONCLUSION: A large proportion of mothers of children with mental retardation experienced substantial parenting stress, especially Chinese and unemployed mothers, and this warrants appropriate intervention.

Analysis of Variance↗

PubMed1999

Non-invasive assessment of myocardial risk and infarct area in canine model of myocardial reperfusion by intravenous contrast echocardiography.

OBJECTIVE: To evaluate the newly developed perfluoropropene-filled echo-contrast agent (FCT-188) in non-invasive assessment of risk areas (RA) and infarct areas (IA) with intravenous myocardial contrast echocardiography (MCE) in canine model of ischemia followed by reperfusion. METHODS: Eight chest-opened Beagle dogs with a 90-minute ischemia followed by a 240-minute reperfusion were studied. MCE was performed after a bolus injection of FCT-188 (0.025 ml/kg, i.v.) into a superficial vein of the forelimb at baseline, 20 minutes after occlusion, and 4 h after reperfusion to non-invasively assess the left ventricular myocardium area (LVMA), myocardial ischemic risk area (RA), and infarct area (IA) in a short-axis view of left ventricle. The accuracy of detecting myocardial perfusion with intravenous MCE was further assessed by in vitro myocardial staining of the matched cross-sections. Both RA and IA were expressed as percent of LVMA. RESULTS: LVMA, RA, IA, and IA/RA ratio were accurately assessed by MCE (LVMA: 6.60 cm2 +/- 0.76 cm2; RA: 35.7% +/- 6.68%; IA: 21.0% +/- 13.2%; IA/RA: 60.3% +/- 31.4%; n = 7) as compared with those of the matched cross-section (LVMA: 6.81 cm2 +/- 0.73 cm2, P = 0.062; RA: 35.3% +/- 9.9%, P = 0.84; IA: 25.10% +/- 14.5%, P = 0.07; IA/RA: 68.0% +/- 22.2%, P = 0.28, respectively). There was a significant correlation of MCE-assessed IA/RA ratio and its corresponding pathologically determined finding in vitro (Y = 1.21 x -21.6, r = 0.73, P = 0.015). No significant changes of electrocardiogram (ECG), mean artery pressures (MAP), pulmonary artery pressures (PAP), and pulmonary artery wedge pressures (PAWP) were found between pre- and post-intravenous injection of FCT-188 at each time point. CONCLUSION: These indicate that FCT-188 can be used to assess risk areas and infarct areas accurately and non-invasively with intravenous MCE in the canine model of a 90-minute ischemia followed by a 240-minute reperfusion and might have potential significance for non-invasive assessment of myocardial reperfusion clinically.

Animals↗

PubMed1999

Apoptosis of hemopoietic cells in irradiated mouse bone marrow.

Apoptosis of hemopoietic cells in bone marrow following radiation has been rarely reported, let alone studied quantitatively and pathologically. LACA mice were irradiated with 2.5, 4.0, 5.5, and 7.0 Gy gamma-rays, and the bone marrow was examined at 6 hours, 1 day, and 3 days after radiation. Semi-thin and thin sections were examined by light and electron microscopy. The number and area density of the apoptotic cells were assessed by means of a Cambridge Quantimet 970 Image Analyzer. We found that apoptosis occurred in only a few hemopoietic cells in the control mouse bone marrow, whereas 6 hours after radiation there were many apoptotic hemopoietic cells in each sample of irradiated bone marrow. Compared with controls, both the number and area density of the apoptotic cells markedly increased in the bone marrow of animals in every radiation dose group, and the difference was statistically significant (p < 0.01). Furthermore, the number and area density increased as the radiation dose increased. Our findings suggest that apoptosis is the main mode of radiation-induced hemopoietic cell death.

Animals↗

PubMed1998

[Effect of allicin on ethanol-induced hepatotoxicity in mice].

To study the effect of allicin, an effective component of garlic, on ethanol-induced hepatotoxicity in mice. The results showed that allicin (10 mg/kg ig, qd x 10) could reverse the higher activities of serum ALT and glutathione s-transferase (GST) in ethanol-treated mice. Furthermore, allicin could significantly enhance the content of hepatic reduced glutathione (GSH), and the activities of hepatic glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Re) and GST in ethanol-induced hepatotoxicity mice. There were no remarkable changes in the hepatic catalase (Cat) and superoxide dismutase(SOD) activities. These results suggested that allicin have the effective hepato-protection on ethanol-induced hepatotoxicity, which is related to its selective effect on the glutathione-related enzyme system.

Animals↗

PubMed1998

Correlation of TP53 mutations and p53 expression in ovarian tumors.

To characterize the involvement of the TP53 tumor suppressor gene in ovarian cancer, mutation analysis of exons 2-11 of TP53 and immunodetection of its protein product, p53, were done in 48 ovarian tumors. Normally, p53 is not immunodetectable. Missense TP53 mutations have been reported to result in p53 accumulation and detection, but mutations generating premature stop codons have not. Mutations were identified in 19 of 41 malignant tumors but not in 5 benign tumors and 2 tumors of low malignant potential. Fifteen of the 19 tumors with mutations also stained positively by immunohistochemistry or Western blot or both. They included 11 missense mutations, 1 in-frame duplication (474ins6), and 3 frameshift mutations generating premature stop codons. The three tumors with frameshifts also had a wild-type TP53 allele and displayed normal size but not truncated p53 by Western blot. This indicates that these tumors express wild-type p53. The significance of TP53 mutations in the development of the three tumors is questionable unless there is a mechanism for inactivating wild-type p53. Nine of the 19 mutations found here, including the 3 frameshifts, were previously not reported in ovarian cancer. Thirteen of the 19 mutations were single nucleotide substitutions with 6 transitions and 7 transversions. The ratio of transversions to transitions (1.2) was different from literature reports (0.5) (P < 0.01). Thus, the spectrum of TP53 mutations in our study differed from other ovarian tumor reports. This difference may be due to population-based differences in the molecular epidemiology of TP53 mutations.

Blotting, Western↗

PubMed1998

[Effects of high dietary zinc on liver function, hepatic drug metabolism enzymes and membrane fluidity in mice].

Mice were fed with high zinc diet (15 g/kg) for 3 weeks. High zinc could cause liver toxicity: 1. inhibiting the activity of GOT and GPT in liver homogenate, reducing GSH and glycogen contents. 2. increasing the activity of aniline hydroxylase and inhibiting the activities of NADPH-cytochrome C reducease, benzo-phytamine-N-demethylase and glutathione S-transferase. The activities of cytochrome P450 and cytochrome b5 were not obviously changed 3. increasing microsomal membrane fluidity in the superficial layers, but not in the deep layers.

Animals↗

PubMed1998

[The ECG&VCG's measurement and analysis system based on PC].

The ECG&VCG's measurement and analysis system based on PC designed by the authors is introduced in this paper. The block diagrams of hardware and software are given as well as characteristics. On the basis of clinic experiments, the relationship between the conventional 12-lead ECG and Frank-VCG is studied with the system. At last a new comprehensive measurement method of the conventional 12-lead ECG and Frank-VCG has been brought forth.

Electrocardiography↗

PubMed1998

The changes and significance of c-kit expression in the irradiated bone marrow of mice.

There have been only a few studies on the expression of c-kit in bone marrow after radiation and radiation-induced apoptosis of hematopoietic cells. LACA mice were examined after irradiation with a dose of 60Co gamma-rays. Using a light microscope, electron microscope, and immunohistochemistry, we studied radiation-induced apoptosis of hematopoietic cells and the expression of c-kit. We found that 5.5 Gy total body irradiation was a sublethal dose for LACA mice, induced suppression of leukocytes in blood, and of nucleated cells in bone marrow. Apoptosis of the hematopoietic cells occurred within 1 day after irradiation. The expression of c-kit was related to the recovery of hematopoiesis and played an important role in early hematopoiesis.

Animals↗

PubMed1998

Interleukin-3 gene expression in irradiated mouse bone marrow.

The expression of endogenous interleukin-3 (IL-3) gene in mouse bone marrow after whole body irradiation was assessed by immunocytochemistry, in situ hybridization (ISH), and in situ reverse transcription PCR (IS RT-PCR). The results showed obvious injury to the bone marrow followed by recovery 4 weeks after radiation. IL-3 protein was increased in the cytoplasm of recovering hematopoietic cells, especially at 21 days after radiation, while the mRNA was negative, except at 15 days when the mRNA was weakly positive by ISH. IS RT-PCR showed that IL-3 mRNA was strongly positive in the cytoplasm of recovering hematopoietic cells, especially at 10 to 15 days after radiation. We postulate that endogenous IL-3 gene may accelerate hematopoietic recovery in irradiated bone marrow and that IS RT-PCR may objectively report the regulation of IL-3 gene expression.

Animals↗

PubMed1998

Epidemiology of immediate and early trauma deaths at an urban Level I trauma center.

The objective of this study is to identify and differentiate the injury patterns and causes of death among patients who died within the 1st hour and those in the period between 1 and 48 hours after hospital admission. Information was collected from the 1994 to 1996 trauma data base at an urban Level I trauma center. The records of 155 trauma patients who died within the 1st hour (immediate trauma death, ITD) and between 1 and 48 hours (early trauma death, ETD) were examined retrospectively. Total and constituent Injury Severity Score (ISS), Trauma Score (TS), and Glasgow Coma Score were analyzed. ITDs constituted 49 per cent of all deaths within 48 hours. Blunt mechanisms accounted for 37 per cent of ITDs and 40 per cent of ETDs (not significant), whereas penetrating trauma accounted for 59 per cent of ITDs and 56 per cent of ETDs (not significant). Exsanguination most commonly caused death among ITDs (54%) and head injury (51%) among ETDs (P < 0.01). Patients who died within the 1st hour had higher ISS (42.6 +/- 23.2, P < 0.03), lower TS (1.7 +/- 1.9, P < 0.0001), and lower Glasgow Coma Score (3.1 +/- 1.1, P < 0.0001) than those who died after the 1st hour. Patients with ITD had a significantly worse chest ISS than those with ETD (47.4 +/- 28.6 vs 19.0 +/- 19.1, P < 0.0001). We conclude that 1) ITD is caused primarily by exsanguination, whereas ETD is largely due to the sequelae of severe neurologic injury; 2) ITD has a significantly lower TS and higher ISS than ETD; and 3) thoracic injuries are more severe among patients with ITDs than among those with ETDs. The severity of thoracic injury among ITDs suggests that rapid surgical intervention is critical during the resuscitation of these severely injured patients.

Adolescent↗

PubMed1997

First astronomical detection of the cumulene carbon chain molecule H2C6 in TMC-1.

The cumulene carbenes are important components of hydrocarbon chemistry in low-mass star-forming cores. Here we report the first astronomical detection of the long-chain cumulene carbene H2C6 in the interstellar cloud TMC-1, from observations of two of its rotational transitions: J(K,K') = 7(1,7) --> 6(1,6) at 18.8 GHz and 8(1,8) --> 7(1,7) at 21.5 GHz, using NASA's Deep Space Network 70 m antenna at Goldstone, California. In addition we also observed the shorter cumulene carbene H2C4 at the same position. The fractional abundance of H2C6 relative to H2 is about 4.7 x 10(-11) and that of H2C4 is about 4.1 x 10(-9). The abundance of H2C6 is in fairly good agreement with gas-phase chemical models for young molecular cloud cores, but the abundance of H2C4 is significantly larger than predicted.

Astronomy↗

PubMed1997

[The effects of high dietary zinc on alloxan induced diabetic mice].

The effects of high dietary zinc on alloxan induced diabetic mice were studied. The results showed that high zinc could sharply decrease the body weight and increase food intake, water intake and urine of diabetic mice, and increase blood sugar levels in diabetic mice. After alloxan injection in diabetic model group, urine sugar levels reached [symbol: see text] at the 2nd day and [symbol: see text] at the 6th day. After alloxan injection in high-zinc-diabetic mice group, urine sugar levels reached [symbol: see text] and [symbol: see text] at the 2nd and the 4th day, respectively. These results suggested that the high level of dietary zinc may be damage to diabetic patients.

Animals↗

PubMed1997

[Effects of high dietary zinc on mice (II)--Influence on growth, blood composition and immune function].

The effects of high-dietary-zinc (HZ, 1.5 g/kg) on growth, blood composition and immune function were studied with a high-dietary-zinc model of mice. By 3 weeks, the body weight and food consumption of mice were significantly lower in HZ group than those in control group. The concentrations of hemoglobin and blood calcium decreased significantly and the platelet and cholesterol levels increased significantly in HZ group. The HZ group showed a spleen swelling and depressed immune function.

Animals↗