[Effects on the normalization of amino acids in metabolic support for trauma surgical patients]

Both serum and muscle intracellular amino acids pattern are changed after trauma. The formulation of amino acid solutions is important for the balance of the patient's serum or intracellular amino acids. In 45 gastric cancer patients after total gastrectomy, the efficacy of individualizal amino acid solution (IDAA) was compared with that of other two balance amino acid solutions. The result showed that metabolic support with IDAA could decrease the muscle intracellular phenylalanine level and increase the levels of free neoglycogenic amino acids, arginine and ornithine both in serum and muscle cells. It is beneficial to the early recovery from trauma and normalization of serum or muscle amino acids pattern.

Radiation hybrids for mapping and cloning DNA sequences of distal 16p

Three hundred fifteen radiation hybrids (RH) were isolated using a monochromosomal cell hybrid containing chromosome 16 only. A panel of 18 RH, which showed breakpoints among four markers (3.15, 26.6, 3'HVR, and 5'HVR) mapping in the distal portion of 16p, were selected and characterized for the retention of nine additional DNA sequences already localized in this region, and for one centromeric sequence. One or more breakpoints were identified in nine of the 12 intervals defined by the 13 single-copy sequences used. This panel of RH represents a tool for the construction of a detailed physical map of the distal part of 16p and for cloning sequences located in the proximity of disease genes. Three inter-Alu DNA sequences, amplified from one of these RH containing the autosomal dominant polycystic kidney disease (PKD1) gene, were cloned and mapped in the panel. Sequencing of the ends of one of three clones showed a (CAAA)n repeat, which revealed a two-allele polymorphism.

[Mechanisms of protective action of radix Salviae miltiorrhizae (RSM) against experimental hepatic injury in rats]

The results indicated that RSM could significantly inhibit the lipid peroxidation of normal livers and cultured hepatocytes of rats, induce liver microsomal cytochrome P450 in normal rats, increase nucleic acids, proteins, urea and cerolloplasmin of damaged cultured hepatocytes of rats, relieve ultrastructural damage of cultured hepatocytes induced by CCl4. The pharmacological actions mentioned above should be considered as important mechanisms of RSM against liver injury.

Availability of primate species, research, and management in China

Approximately 30 institutions are currently engaged in primate research and management in China. New studies record 20 species of primates and their distribution throughout China.

Suppression of lymphokine production in anti-minor histocompatibility antigen responses

Allogeneic immunizations between mice strains that differ at multiple loci coding for minor histocompatibility antigens (mha) result in a variety of immune responses, including the induction of cytotoxic T cells, helper T cells, and delayed hypersensitivity reactions. However, high-dose intravenous immunization induces a population of cells that can suppress these responses. In this paper, we show that the transfer of this suppressor population in vivo is accompanied by a reduced ability of immune cells to produce the two lymphokines interleukin-2 (IL-2) and interleukin-3 (IL-3). In a different assay of suppressor function, suppressor cells were co-cultured with responder cells in vitro. Under these conditions, the presence of suppressor cells resulted in a lowered net production of IL-2, but not IL-3. Possible mechanisms for this phenomenon are discussed.

[Effect of monocrotaline on human kidney cells]

The effect of monocrotaline on human kidney cells has been studied by means of monolayer cell culture, cytochemistry and 3H-thymidine incorporation. The result shows that this drug can inhibit cell DNA synthesis, featuring an irreversible damaging action to DNA templet. Also, when the process of glycolysis and saccharide utilization in the cells is inhibited, the amount of lactic acid produced decreases and the pH value becomes higher.

[The in vitro effect of silica fibers on macrophage-mediated cytotoxic activities in mice]

The in vitro effects of silica fibers on macrophage-mediated cytotoxic activities in mice were studied, including 1) macrophage-mediated tumor cytolysis (MTC), 2) macrophage-mediated tumor cytostasis (MTCS) and 3) antibody-dependent cell-mediated cytolysis (ADCC), we found that silica fibers markedly inhibited both MTC and ADCC but slightly promoted MTCS. Silica fibers were active during the activation phase mediated by macrophage-activating factor as well as in the effector phases of MTC and MTCS. In ADCC, increasing the antibody titer could not abrogate the inhibitory effect of silica fibers.

Diet-induced DNA damage and altered nucleotide metabolism in lymphocytes from methyl-donor-deficient rats

Tumor induction with chronic feeding of methyl-donor-deficient diets has been well established; however, the biochemical and molecular mechanisms which predipose to tumorigenesis in this model are still not well understood. The purpose of the present investigation was to assess DNA damage and altered nucleotide metabolism in lymphocytes from Fischer 344 rats fed one of four semi-purified diets: (i) deficient in methionine and choline; (ii) deficient in folic acid; (iii) deficient in methionine, choline and folic acid; or (iv) a supplemented control diet. The accumulation of DNA-strand breaks, as assessed by DNA unwinding in alkali, was increased in lymphocytes from both the methionine/choline-deficient and folate-deficient groups, but was most severe in the group deficient in all three methyl donors. Lymphocyte DNA damage was consistently associated with alterations in folate-dependent thymidylate synthesis, and a decrease in intracellular levels of the DNA-repair-associated pyridine nucleotide, nicotinamide adenine dinucleotide. In the liver, a synergistic lipotropic interaction between folate deficiency and methionine/choline deficiency was observed, confirming the metabolic inter-relationship between these nutrients. Taken together, the results suggest that folate deficiency interacts with methionine/choline deficiency to potentiate symptoms of methyl-donor deficiency and that alterations in folate-dependent thymidylate synthesis are related to DNA damage in lymphocytes. These metabolic aberrations may contribute to immune dysfunction with chronic feeding of methyl-donor-deficient diets.

DNA strand break accumulation, thymidylate synthesis and NAD levels in lymphocytes from methyl donor-deficient rats

Although tumor development with methyl donor-deficient diets has been well established, the biochemical and molecular mechanisms which predispose to tumor development are not yet understood. In the present study, DNA damage and nucleotide metabolism associated with DNA synthesis and repair were evaluated in splenic lymphocytes from rats fed a basal diet low in methionine and lacking in choline and folate or a supplemented control diet for a period of 3 wk. The accumulation of DNA strand breaks, as assessed by DNA unwinding in alkali, was found to be significantly elevated in lymphocytes from rats fed the methyl donor-deficient diet and was associated with an increase in mitogen-stimulated incorporation of [3H]-thymidine via the salvage pathway for thymidylate synthesis. In addition, a significant decrease in the DNA repair-associated pyridine nucleotide, NAD, was observed in lymphocytes from the deficient group and was associated with a decrease in total spleen cell numbers. These results suggest that alterations in nucleotide metabolism and DNA damage are induced when methyl donor pools are stressed by dietary deficiency.

Examination of the clonal deletion hypothesis following transfusions in rat cardiac transplants

To test the clonal deletion hypothesis, different levels of immunization were carried out by 0, 1, 2, or 3 transfusions preoperatively, together with 10 methods of immunosuppression. In this way, it was hoped that we could determine the optimal way to immunize and the optimal immunosuppressant treatment to deactivate the responding cells. With the Buffalo-to-Lewis rat heart allograft model, the control mean survival rate was 7 days. Rats with 2 or 3 transfusions had 5- and 12-day survival rates, respectively. If azathioprine was given in addition before grafting, 19- and 18-day survival rates were seen, and if azathioprine was given after grafting, extended survivals of 33 and 34 days were achieved. The longest survival rate of greater than 52 days was obtained by a single transfusion and 25 mg/kg/day of cyclophosphamide given before transplantation. Splenectomy following 2 or 3 transfusions prolonged survival rates to 16-18 days, suggesting that mechanical removal of immunized cells is somewhat effective. Most of the antibody produced by one transfusion was IgM, as were antibodies that resulted from transfusions followed by azathioprine. It is possible that reduction of IgG-producing cells is important. These results are consistent with the clonal deletion theory, although they do not necessarily provide final proof. The experiments suggest that the optimal transfusion effect may be obtained with minimal immunization (1 transfusion) and proper immunosuppression before transplantation.

Cochlear implants: overview of safety and effectiveness. The FDA evaluation

Under authority of the Federal Food, Drug, and Cosmetic Act, as amended in 1976, the Food and Drug Administration requires manufactures of new medical devices, such as cochlear implants, to demonstrate the safety and effectiveness of their devices before marketing them. This article describes the FDA review process and the kinds of data the FDA is looking for in premarket approval applications for cochlear implants. It also discusses some of the issues surrounding the premarket approval applications which have already been approved.

Mesenteric cysts and intra-abdominal cystic lymphangiomas

Although mesenteric cysts and intra-abdominal cystic lymphangiomas are uncommon and clinically confusing lesions, histologic and ultrastructural evidence suggests that they are pathologically distinct. Differentiation of these lesions is important since lymphangiomas may follow a proliferative and invasive course. Of 28 cases documented at laparotomy, histologically eight patients (29%) had cystic lymphangiomas and 20 patients (71%) had mesenteric cysts. Lymphangioma was found to be exclusively a disease of childhood and young adulthood (mean age, 10 years); mesenteric cyst was found in all age groups (mean age, 44 years), and two thirds of these patients were over 40 years old. Patients with lymphangiomas more frequently were male (75% vs 30%), symptomatic (88% vs 35%), and had ascites (50% vs 0%) and larger lesions (mean, 8.8 vs 4.7 cm) when compared with patients with mesenteric cysts. Complete excision was possible in all but four patients, with no operative deaths and a postoperative complication rate of 7%. After a mean follow-up period of four years, there were no recurrences among 16 patients who had undergone complete excision.

Apollo 16 Geochemical X-ray Fluorescence Experiment: Preliminary Report

The lunar surface was mapped with respect to magnesium, aluminum, and silicon as aluminum/ silicon and magnesium/ silicon intensity ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide new data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The aluminum/ silicon and magnesium/ silicon concentration ratios correspond to those for anorthositic gabbros through gabbroic anorthosites or feldspathic basalts. The x-ray results suggest the occurrence of this premare crust or material similar to it at the Descartes landing site.

Apollo 15 Geochemical X-Ray Fluorescence Experiment: Preliminary Report

Although only part of the information from the x-ray fluorescence geochemical experiment has been analyzed, it is clear that the experiment was highly successful. Significant compositional differences among and possibly within the maria and highlands have been detected. When viewed in the light of analyzed lunar rocks and soil samples, and the data from other lunar orbital experiments (in particular, the Apollo 15 gamma-ray spectroscopy experiment), the results indicate the existence of a differential lunar highland crust, probably feldspathic. This crust appears to be related to the plagioclase-rich materials previously found in the samples from Apollo 11, Apollo 12, Apollo 14, Apollo 15, and Luna 16.

Rapid Chemical Confirmatory Method for Aflatoxin B1. I. Development of the Method

A revised method has been developed for the formation of anatoxin Bi derivatives for chemical confirmation. The method involves treating the aflatoxin-containing extract with concentrated HCl and water to yield the water adduct and with concentrated HCl and acetic anhydride to yield the epimeric acetates. The method is considered simpler to perform and produces fewer side reactions than the AOAC official final action method.