[Effects of resuscitation with hypertonic sodium lactate dextran 70 on cardiac function in severely burned dogs]

This comparative study was performed to evaluate the effects of resuscitation of burn shock with hypertonic sodium lactate dextran 70(HLD solution: Na+250 mmol/L and 6% dextran 70) and lactate Ringer' solution on cardiac function, lipid peroxide and SOD activity of heart tissue. Dogs with 35% TBSA third degree burns received, one hour postburn, either HLD resuscitation (HLD group, n = 6) in the amount of 19.6 ml.kg-1/g hours, followed by LR 6 ml.kg-1/% TBSA, or LR resuscitation (LR group, n = 6) in the amount of 8 ml.kg-1/% TBSA LR solution. The results of this experiment showed that cardiac index (CI) of HLD group was much higher than that of LR group at 4, 8, 12, 24 hours postburn. The dp/dt max and-dp/dt max of HLD group were much higher than that of LR group at 12.24 hours postburn. Level of MDA in heart tissue of HLD group (1.74 +/- 0.28 10 mol/g heart tissue) was much lower than of LR group (3.23 +/- 0.56 10 mol/g heart tissue) at 24 hours postburn (P < 0.01). Meanwhile, SOD activity in heart tissue of HLD group (157.49 +/- 32.23 u/mg heart tissue) was much higher than that of LR group (46.88 +/- 16.28 u/mg heart tissue) (P < 0.01). These results suggested that HLD resuscitation might be beneficial in improving postburn cardiac function and attenuating postburn oxidant-induced lipid peroxidation in heart tissue not only by its "oxygen scavenger" effect, but also by its elevation of SOD activity of heart tissue.

Effects of axial ligand replacement on the redox potential of cytochrome c

The formal potentials (E0') and electron transfer numbers (n) of imidazole (Im), 1-methylimidazole (1-MeIm), and 1-ethylimidazole (1-EtIm) complexes of cytochrome c have been determined for the first time using optically transparent thin-layer spectroelectrochemistry. In comparing these results with the E0' value of the cytochrome c, their potentials at infinite dilution have been calculated, which indicate that axial replacement of methionine-80 by Im, 1-MeIm, and 1-EtIm gives rise to 426, 359, and 327 mV negative shifts relative to that of native cytochrome c, respectively. Thereby, the origins of the effects of axial substitution on redox potential are discussed.

Overexpression of p53 predicts organ preservation using induction chemotherapy and radiation in patients with advanced laryngeal cancer. Department of Veterans Affairs Laryngeal Cancer Study Group

A critical research frontier in head and neck oncology involves defining the use of induction chemotherapy regimens to allow organ preservation and to avoid functionally debilitating surgical resections. Completed clinical trials in laryngeal cancer indicate that such an approach is feasible, but progress thus far has been limited by our inability to predict which patients are likely to respond to chemotherapy and preserve their larynx. Mutation of the p53 tumor-suppressor gene is the most common genetic alteration identified thus far in human cancers, and it may be important in regulation of cell proliferation and chemosensitivity. To determine whether p53 overexpression predicts chemotherapy response, organ preservation, and survival in patients with advanced laryngeal cancer, we analyzed immunohistologic expression of p53 in tissue sections from 178 patients with advanced laryngeal cancer who were entered in the Department of Veterans Affairs Laryngeal Cancer Cooperative Study, a multiinstitutional clinical trial comparing induction chemotherapy (cis-platinum and 5-fluorouracil) plus radiation therapy (94 patients) to surgery plus postoperative radiation therapy (84 patients). Larynx preservation was significantly higher in the group of patients whose tumors overexpressed p53 (74% vs. 52.5%; p = 0.03). The presence of p53 overexpression did not predict survival in either the surgery or the chemotherapy groups (p = 0.82 and p = 0.53).

The crystal structure of deshexapeptide (B25-B30) insulin at 0.25 nm resolution

The determination of deshexapeptide (B25-B30) insulin (DHI) was divided into two steps. At the first step, the rough structure model of DHI molecule was determined by using the molecular replacement method associated with the molecular close-packing method at 0.30 nm resolution based on the reflection data collected on four-cycle diffractometer. At the second step, the DHI model was adjusted and refined at 0.25 nm resolution based on the data collected on Area Detector. 40 water molecules were determined during the refinement, the final R-factor is 0.185 with R.M.S. deviation of 0.002 nm for bond lengths and 1.9 degrees for bond angles. The differences in conformation and function of DHI with other insulin analogues were compared and discussed.

[Isolation of fusarium and extraction of its toxin from buckwheat grown in an area with "endemic breast enlargement" disease]

Fusarium was isolated and its toxin was extracted from the buckwheat grown in an epidemic area with "endemic breast enlargement" disease. The toxin was determined with thin layer chromatography and mass spectrography. Results showed there were more than four kinds of mould, including fusarium, isolated from buckwheat grown in the endemic disease area. All the buckwheat grown in the area were infected with mould and 34% with fusarium. Three kinds of toxin were extracted from the buckwheat, with rates of flow of 0.23, 0.47 and 0.90, respectively, in thin layer chromatography. And, zearalenone was extracted from the buckwheat and identified by mass spectrography.

The histidyl-tRNA synthetase-related sequence in the eIF-2 alpha protein kinase GCN2 interacts with tRNA and is required for activation in response to starvation for different amino acids

Protein kinase GCN2 is a multidomain protein that contains a region homologous to histidyl-tRNA synthetases juxtaposed to the kinase catalytic moiety. Previous studies have shown that in response to histidine starvation, GCN2 phosphorylates eukaryotic initiation factor 2 (eIF-2), to induce the translational expression of GCN4, a transcriptional activator of genes subject to the general amino acid control. It was proposed that the synthetase-related sequences of GCN2 stimulate the activity of the kinase by interacting directly with uncharged tRNA that accumulates during amino acid limitation. In addition to histidine starvation, expression of GCN4 is also regulated by a number of other amino acid limitations. Questions that we posed in this report are whether uncharged tRNA is the most direct regulator of GCN2 and whether the function of this kinase is required to recognize each of the different amino acid starvation signals. We show that GCN2 phosphorylation of eIF-2, and the resulting general amino acid control pathway, is stimulated in response to starvation for each of several different amino acids, in addition to histidine limitation. Cells containing a defective aminoacyl-tRNA synthetase also stimulated GCN2 phosphorylation of eIF-2 in the absence of amino acid starvation, indicating that uncharged tRNA levels are the most direct regulator of GCN2 kinase. Using a Northwestern blot (RNA binding) assay, we show that uncharged tRNA can bind to the synthetase-related domain of GCN2. Mutations in the motif 2 sequence conserved among class II synthetases, including histidyl-tRNA synthetases, impair the ability of this synthetase-related domain to bind tRNA and abolish GCN2 phosphorylation of eIF-2 required to stimulate the general amino acid control response. These in vivo and in vitro experiments indicate that synthetase-related sequences regulate GCN2 kinase function by monitoring the levels of multiple uncharged tRNAs that accumulate during amino acid limitations.

[Gene diagnosis of adult polycysitic kidney disease--using polymorphic microsatellite markers]

Gene diagnosis of adult polycystic kidney disease (APKD) is possible by genetic linkage analysis using linked restriction fragment length polymorphisms (RFLP) on both sides of the PKD1. This technique is laborious, expensive and sample- time- consuming. SM7 is a polymorphic microsatellite that tightly linked with the PKD1. We combined PCR with polyacrylamide gel electrophoresis and method of gel Ag+ staining to detect the allelus and genotype frequencies of the microsatellite amplificated in unrelated Chinese population. The study of 8 APKD families with SM7 demonstrated that the technique is quite simple, fast, sensitive and does not require the use of radioisotopes and ultraviolet. It could provide a powerful method for the presymptomatic and prenatal diagnosis of APKD.

[Clinicopathological features and surgical treatment of early gastric cancer]

We analyzed retrospectively the clinicopathological data obtained from 126 patients with early gastric cancer (EGC) to elucidate the relationship between pathological patterns and lymphatic metastasis and the criteria of selecting appropriate surgery. Lymph node metastasis was 3.1% (2/65) in mucosal and 16.4% (10/61) in submucosal tumors respectively (P < 0.05). 26 patients with tumors smaller than 10 mm had no lymphatic metastasis, and 100 patients with tumors larger than 10mm in size had 8% (8/100) n1 positive, 4% (4/100) n2 positive and 7% (7/100) lymphatic duct invasion (P < 0.05). The 5-year survival rate in patients with lymphatic metastasis (79%, 15/19) was significantly lower than that in patients without lymphatic metastasis (97.2%, 104/107) (P < 0.01). It seemed that the most important prognostic factor is whether the presence of lymphatic metastasis or not. Lymphadenectomy is expected to improve the survival rate in EGC. D2 procedure is generally recommended as a standard operation for EGC, especially for the submucosal or larger lesion. Anyhow, D1 operation is sufficient for mucosal or smaller cancer, and D3 is suitable only for EGC patients with multifoci, superficially spreading type and group 3 lymph node metastasis.

[Hepatic albumin's mRNA in nephrotic syndrome rats treated with Chinese herbs]

It was found in our previous studies that two Chinese herbs, Astragali and Angelica (A & A), with a high protein diet could protect the decrease of serum albumin and markedly increase the synthesis rate of protein by 18N-glycine metabolic study in nephrotic rats. A further experiment was designed to investigate the effects of A&A and high protein intake on the level of hepatic albumin's mRNA in nephrotic rats. Male S. D. rats were divided into 3 groups: high protein diet alone (39.7% HP); HP with nephrotic syndrome (HPN); and HPN with therapy (HPNT). Nephrotic syndrome in rat was induced by accelerated nephrotoxic nephritis, withfed A&A (2 g of each in 3 ml) daily for 14 days. At the 15th day, the serum and liver were collected and the level of serum albumin and mRNA were measured with biochemistry, Northern blot, dot blot hybridization and quantity in laser density screening. The level of serum albumin in HPNT was higher than that of HPN (3.7 +/- 0.1 vs 2.9 +/- 0.29, P < 0.01) with an unchanged urinary output. The level of hepatic albumin mRNA in HPNT was higher than HPN (2.56 +/- 0.24 vs 1.7 +/- 0.12, P < 0.01) and HP (2.56 +/- 0.24 vs 1.25 +/- 0.24, P < 0.01). We conclude that in a molecular biologic level A&A combined with high protein intake could increase the albumin synthesis in the liver of nephrotic rat.

Epidemiological survey of primary angle-closure glaucoma in Doumen

PURPOSE

To determine the prevalence of primary angle-closure glaucoma (PACG) in Doumen Countty, Guangdong province.

METHODS

Four villages from eight districts in doumen were selected by stratified, cluster and random sampling. Of a total of 1055 people aged 45 years or over, 932 (88.62%) were examined. The examination and diagnostic criterion were similar to those of shunyi survey.

RESULTS

The prevalence of PACG in subjects over 45 year of eye is 0.64%, in those over 50 years of age is 0.85% in Doumen, which is significantly lower than the corresponding figure of 1.99% in shunyi (P < 0.05).

CONCLUSION

This study identifies the prevalence of PACG in Doumen is lower than in Shunyi.

[An epidemiological survey of primary angle-closure glaucoma in Doumen county Guangdong]

A comparison between the results of an epidemiological study of primary angle-closure glaucoma (PACG) in Doumen County, Guangdong in 1990 and those of a similar study in Shunyi County, Beijing in 1985 was reported. The prevalence of PACG in subjects over 45 years old was 0.64% and that, over 50 years, 0.85% in Doumen, while that, over 50 years, 1.99% in Shunyi (P < 0.05). There was significant difference in the prevalence of PACG between the two counties and the difference was discussed.

Myasthenia gravis-like syndrome induced by expression of interferon gamma in the neuromuscular junction

Abnormal humoral responses toward motor end plate constituents in muscle induce myasthenia gravis (MG). To study the etiology of this disease, and whether it could be induced by host defense molecules, we examined the consequences of interferon (IFN) gamma production within the neuromuscular junction of transgenic mice. The transgenic mice exhibited gradually increasing muscular weakness, flaccid paralysis, and functional disruption of the neuromuscular junction that was reversed after administration of an inhibitor of acetylcholinesterase, features which are strikingly similar to human MG. Furthermore, histological examination revealed infiltration of mononuclear cells and autoantibody deposition at motor end plates. Immunoprecipitation analysis indicated that a previously unidentified 87-kD target antigen was recognized by sera from transgenic mice and also by sera from the majority of human MG patients studied. These results suggest that expression of IFN-gamma at motor end plates provokes an autoimmune humoral response, similar to human MG, thus linking the expression of this factor with development of this disease.

The relationship of dietary animal protein and electrolytes to blood pressure: a study on three Chinese populations

The relationship of diet to blood pressure was studied in a total of 705 men and women aged 40-59 from three Chinese population samples having different mean blood pressure and dietary sodium and animal protein intake. Two groups were farmers from Shanxi in northern China, and Guangxi in southern China, and the third were fishermen from Zhejiang, eastern China. Three 24-hour dietary recalls were done for each participant. Serum and overnight urine amino acids were measured in random subsamples. Determination of electrolytes in three 24-hour urine specimens was done in an additional sample of 59 men in each population. Results of multiple or stepwise regression showed: 1) in the pooled group, individual intake of sodium was positively associated with systolic blood pressure; 2) when stratifying by median calcium intake, a positive association of dietary sodium or sodium/potassium was found only in the group with calcium intake lower than the median; 3) daily intake of animal protein, urinary sulphate and certain serum and urine amino acids formed from protein metabolism, were inversely associated with blood pressure.

Diurnal blood pressure variation and dietary salt in spontaneously hypertensive rats

We have previously reported that high dietary salt exposure significantly increases daytime mean arterial pressure in spontaneously hypertensive rats (SHR) but not in normotensive Wistar-Kyoto (WKY) controls. In the present study, we used a telemetry monitoring system to evaluate the effects of high dietary salt exposure on diurnal variation of mean arterial pressure and heart rate in SHR and WKY rats. After implantation of a radio frequency transducer, SHR and WKY rats were maintained on either high (8%) or basal (1%) salt diets. Hemodynamic values were then analyzed for diurnal variation with the use of a nonlinear data-fitting program. After 2 weeks of dietary exposure, high salt-fed SHR had significantly greater 24-hour mean arterial pressure (156 +/- 3 mmHg) than SHR receiving basal (135 +/- 2 mmHg) and WKY rats receiving high (100 +/- 2 mmHg) or basal (100 +/- 1 mmHg) salt diets. Rhythm analysis indicated significant increases in both daytime and nighttime mean arterial pressure during high salt exposure in SHR. In WKY rats, high salt exposure increased nighttime but not daytime mean arterial pressure, with no net effect on 24-hour mean arterial pressure. High dietary salt exposure significantly decreased heart rate in both SHR and WKY rats, and it did not significantly alter the pattern of diurnal blood pressure or heart rate variation. These results indicate that WKY rats manifest an acute sensitivity to salt ingestion but have compensatory mechanisms sufficient to prevent sustained increases in mean arterial pressure; such mechanisms are lacking in SHR.

Enrichment of DNA fragments for deleted sequences in human genome with nuclease S1 digestion and PCR amplification

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Toxicity and toxicokinetics of MeISP in isolated rat hepatocytes

Toxicity and toxicokinetics of a new organophosphorus insecticide, MeISP, in isolated rat hepatocytes were studied. It was found that at the final concentration of 1.5 mmol/L, MeISP can (1) result in an increase of leakage of intracellular enzymes, alanine amino-transferase (ALT), lactate dehydrogenase (LDH), beta-glucuronidase (beta-GDase) and acid phosphatase (AcP) to the medium in a dose-dependent fashion; (2) give rise to obvious plasma membrane blebbing; (3) rapidly deplete the intracellular GSH and (4) almost completely inhibit the protein synthesis and gluconeogenesis from sodium pyruvate. The kinetics study showed that at the final concentration of 15 mumol/L, MeISP is rapidly metabolized and this process fits the one-compartment model. The metabolism of MeISP in the hepatocytes with phenobarbital-induced microsomal enzymes is accelerated. These results indicate that (1) MeISP has obvious toxicity to isolated rat hepatocytes and isolated hepatocytes provide a suitable system to examine the toxic effects of xenobiotics at the cellular level and (2) MeISP is metabolized mainly by microsomal enzymes.

[An experimental study on cultivation of human trigeminal ganglionic cell in vitro and its sensitivity to infection of herpes simplex virus type 1]

We firstly report an experimental study on the sensitivity of primary cultural human trigeminal ganglionic cells infected by herpes simplex virus type 1 (HSV-1) in different time-points. The results indicate that the neuron of human trigeminal ganglia is the most sensitive cell type, the antigen of HSV-1 replicates rapidly within the cytoplasm and cell nucleus, the fibroblasts and glia cells are infected partly by the virus. Therefore, perhaps the neuron is the main harboring cell type.

Postnatal anti-interferon-gamma treatment prevents pancreatic inflammation in transgenic mice with beta-cell expression of interferon-gamma

beta-Cell-targeted expression of interferon-gamma (IFN-gamma) leads to pancreatitis and immune sensitization to beta-cells. This transgenic model is used to explore the possible role of locally produced IFN-gamma in loss of tolerance to beta-cell-specific antigens in insulin-dependent diabetes mellitus (IDDM). The aim of the present study was to test if postnatal treatment with antibodies against IFN-gamma could inhibit morphological changes in the IFN-gamma transgenic pancreas, even though the transgene is expressed during embryogenesis. Treatment with a monoclonal rat anti-mouse IFN-gamma antibody for 6 weeks, starting from 5 to 7 days of age, completely inhibited IFN-gamma-induced morphological changes in the pancreas, and only a modest inflammatory reaction emerged after prolonged treatment for 12 weeks. The lack of morphological changes may reflect the ability of nonterminally differentiated neonatal pancreatic cells to compensate for transgene-induced pathological alterations occurring in utero prior to the antibody treatment. We conclude that inflammation and altered pancreas morphology in the transgenic mice is the result of the biological actions of IFN-gamma and not by disrupted islet development due to transgene overexpression in the pancreatic beta-cells. Furthermore, our treatment schedule can serve as a model for future intervention studies in the transgenic mice, elaborating the role of IFN-gamma in localized inflammatory reactions, IDDM in particular.