Strong excitonic nonlinearity in a P-I-N photodiode incorporating narrow asymmetric coupled quantum wells

Strong excitonic nonlinearity in the photoconductive response of a P-I-N photodiode incorporating narrow asymmetric coupled quantum wells has been observed at 78 K. When the P-I-N photodiode is overbiased, the heavyhole energy levels in the two coupled quantum wells are moved toward the resonance by increasing the laser intensity. Also, both the light-hole and the heavy-hole excitonic transitions undergo intensity-dependent shifts. Both these effects indicate intrinsic change of bias due to redistribution of photogenerated carriers and, therefore, the existence of an intrinsic feedback mechanism. The magnitude of the blue shift of the heavy-hole excitonic transitions significantly increases when the laser intensity is changed from 9.2 to ~270 mW/cm(2).

[Aluminum and fluorine absorption in a perfusion system of rat small intestine in vivo]

Mixtures of aluminum an fluorine in two different ratios in tris-hydroxy-methyl-aminomethane buffered media of pH 7.0 were perfused respectively through the small intestine of the in vivo rat over a period of 40 min. The contents of aluminum and fluorine in the portal vein blood obtained from different perfusion periods were detected and determined simultaneously. The results showed that fluorine absorption was not significant in the mixtures. An obviously large amount of aluminum was absorbed in the mixture with a higher proportion of aluminum (4660 micrograms/ml Al + 200 micrograms/ml F/L), while in the mixture with a lower dose of aluminum (860 micrograms/ml Al + 200 micrograms F/L), a small quantity of aluminum was absorbed. It is evident that the mechanism by which aluminum inhibits fluorine toxicity is that aluminum decreases the intestinal fluorine absorption by the formation of aluminum fluoride complex.

[Distribution of vanadium in tissues of nonpregnant and pregnant Wistar rats]

This paper reports tissue distribution of vanadium in nonpregnant and pregnant Wistar rats. The experimental results showed that vanadium concentrations in nonpregnant rats were respectively from high to low: I. no treatment: ovary greater than uterus greater than kidney greater than lung greater than heart muscle greater than spleen greater than brain greater than liver greater than blood; II. 4h after single i.p. injection of V2O5 (5 mg/kg): kidney greater than ovary greater than liver greater than bone greater than uterus greater than lung greater than heart muscle greater than spleen greater than brain greater than blood. The results suggest that female genital organs are important organs in distribution of vanadium. The kidney is a main excretory organ. After 24h of treatment, a larger amount of vanadium in body has been excreted. Vanadium can pass through blood-brain barrier. Distribution of vanadium on gestation days 12 after 4h single i.p. injection of V2O5 (5 mg/kg) is: kidney greater than ovary greater than uterus greater than placenta greater than liver greater than fetus greater than bone greater than heart muscle greater than lung greater than brain greater than spleen greater than blood; on gestation days 16-18 after 4h single i.p. injection of V2O5 (5 mg/kg) is: kidney ovary greater than placenta greater than lung greater than bone greater than uterus greater than heart muscle greater than spleen greater than fetus greater than liver greater than brain greater than blood; after 24h (on gestation days 16-18) is: kidney greater than ovary greater than placenta greater than spleen greater than bone greater than lung greater than liver greater than fetus heart muscle greater than brain blood.(ABSTRACT TRUNCATED AT 250 WORDS)

[Longitudinal changes of serum specific antibodies in Lewis rats immunized with IRBP]

The serum antibodies specific to either interphotoreceptor retinoid-binding protein (IRBP) or retinal S-antigen were longitudinally determined in Lewis rats immunized with 50 x 10(-6)g of IRBP emulsified with complete Freund's adjuvant. To our knowledge, it is the first time to purify IRBP and to address the experiment with IRBP in China. It was shown that the antibody specific to IRBP appeared on the 7th day, followed by a gradual increase, and reached its peak on the 26th day after immunization. No antibody specific to S-antigen was found. The relation between anti-IRBP antibody and experimental autoimmune uveoretinitis (EAU) which occurred in the increasing phase of the antibody suggests that the humoral immunity may be implicated in the pathogenesis of EAU.

Induction of cytokines in normal placental cells by the human immunodeficiency virus

Placental cotyledon mononuclear cells (CMC) resemble peripheral blood monocytes/marcophages (MM) with respect to their expression of surface antigens and cellular function. CMC also express the CD4 antigen receptor and are thus susceptible to infection with the human immunodeficiency virus (HIV). When vertical transmission of HIV from mother to fetus occurs, the infection often remains latent until appropriate factors initiate the transcription of virus-specific mRNA. Cytokines, such as interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) which are produced by MM, up-regulate HIV expression in infected cells. The induction of cytokines in MM does not require active infection with HIV since heat-inactivated HIV (iHIV) and envelope gp120 caused cytokine secretion. We studied the ability of CMC from normal placentas to secrete these cytokines following stimulation with endotoxin, iHIV, recombinant GP160 and GAG55, and synthetic p17, HGP-30. Whereas CMC spontaneously secreted low levels of IL-1 beta and TNF-alpha, they constitutively secreted high levels of IL-6. All cytokine levels could be boosted by endotoxin. GP160, iHIV, and HGP-30 failed to augment cytokine levels above baseline. In contrast, GAG55 significantly boosted only TNF-alpha. The relevance of these findings is discussed with respect to the putative roles of cytokines in the immunoregulation of HIV in utero.

Anorexia reduces the severity of cryptobiosis in Oncorhynchus mykiss

Cryptobia salmositica multiplied more rapidly and caused a more severe disease with a higher mortality (65%) in rainbow trout (Oncorhynchus mykiss) fed a 52% protein diet than in fish fed 37 or 22% protein diets (25 and 30% mortalities, respectively). Also, plasma protein was significantly higher in fish fed a 52% protein diet than in fish fed 37 or 22% protein diets. Anorexia in infected trout was related positively to parasitemia and was most significant at 4 wk postinfection. During the chronic phase of the infection, food consumption increased with declining parasitemia. It is hypothesized that anorexia lowers plasma protein level, which reduces the multiplication rate of parasites, thus decreasing the severity of the disease.

Specific targeting of mitomycin C to tumors by anti-gastric cancer monoclonal antibody

In the present study, an anti-gastric cancer monoclonal antibody, MGb2, was chosen to prepare antibody-mitomycin C (MMC) conjugate with dextran T-40 as intermediary. Twenty molecules of MMC were introduced into each molecule of antibody while the antigen-binding capacity of the antibody was kept well. The conjugate showed selective cytotoxicity upon human gastric cancer cell line SGC-7901. Radioimmunoimaging and biodistribution studies indicated that after conjugation with MMC via dextran T-40 as intermediary, the tumor localization capacity of the antibody was well retained. When tested in nude mice, inoculated with human gastric carcinoma SGC-7901 in bilateral subrenal capsules, intraperitoneal injection of the conjugate daily for 6 days at a dose of 1 mg/kg gave a tumor inhibitory rate of 68.67%, which was far better than that of free MMC or irrelevant conjugate. No synergetic effect was found in regard to the mixture of MGb2 with MMC.

Primary structure and functional activity of a phosphatidylinositol-glycan-specific phospholipase D

A phosphatidylinositol-glycan-specific phospholipase D (PI-G PLD) that specifically hydrolyzes the inositol phosphate linkage in proteins anchored by phosphatidylinositol-glycans (PI-Gs) has recently been purified from human and bovine sera. The primary structure of bovine PI-G PLD has now been determined and the functional activity of the enzyme has been studied. Expression of PI-G PLD complementary DNA in COS cells produced a protein that specifically hydrolyzed the inositol phosphate linkage of the PI-G anchor. Cotransfection of PI-G PLD with a PI-G-anchored protein resulted in the secretion of the PI-G-anchored protein. The results suggest that the expression of PI-G PLD may influence the expression and location of PI-G-anchored proteins.

Expression of multiple species of basic fibroblast growth factor mRNA and protein in normal and tumor-derived mammary epithelial cells in culture

We examined the expression of the basic fibroblast growth factor (bFGF) gene in cultured normal and tumor-derived human mammary epithelial cells at both the transcriptional and translational level. Northern blot analysis revealed three bFGF mRNA transcripts of 7.5, 4.4, and 2.2 kilobases in all four strains (donors) of normal cells (HMECs) we examined and in the immortal mammary cell line HBL-100. Of the four mammary tumor-derived cell lines we examined (MCF-7, BT-474, T-47D, and Hs578T), only the Hs578T cells produced detectable levels of bFGF mRNA. Western blot analysis of cell lysates using an anti-bFGF monoclonal antibody revealed corresponding results. bFGF protein was detected in normal HMEC strains 161 and 48 (other normal strains not tested), in HBL-100 cells, and in Hs578T cells, but not in the other tumor cell lines. In each case, three distinct molecular weight species of bFGF protein were detected which migrated in sodium dodecyl sulfate-polyacrylamide gel at 18, 24, and 27 kDa. We also investigated the ability of bFGF to stimulate the proliferation of normal and tumor-derived mammary epithelial cells. Addition of bFGF to serum-free cultures of these cells had no effect on the proliferation of HMECs under a variety of conditions and was weakly mitogenic for Hs578T cells. Our results indicate that normal HMECs produce bFGF mRNA and protein(s), whereas only some mammary tumor-derived cells express this gene. Thus, our results do not support a general role for expression/overexpression of bFGF in the development of mammary tumors. However, bFGF could play a role in the normal development and homeostasis of the mammary gland.

HLA antigens and Vogt-Koyanagi-Harada's disease

Thirty patients with Vogt-Koyanagi-Harada's disease were typed for HLA-A and HLA-B antigenic determinants by a microlymphocytotoxicity technique. HLA-B22 antigen showed an increased frequency of 43.3% in the patient group (relative risk = 8.69; exact P < 0.0001; corrected P < 0.0025) compared with normal control group (frequency = 7.69%). This association suggests that immunogenetic factor may play an important role in the pathogenesis of Vogt-Koyanagi-Harada's disease.

[Research on the processing of Angelica based on the analysis of water soluble constituents]

In this paper, a comparative study on the contents of water-soluble and alcohol-soluble tannin and ferulic acid in Angelica and its processed products is reported. The result shows that different processing methods have significant effects on the above constituents, thus administering to the interpretation of the theory of Angelica processing.

Use of MG series monoclonal antibodies in the diagnosis and experimental targeting therapy of gastric cancer

In order to facilitate early diagnosis and improve the treatment of gastric cancer, 12 murine hybridoma cell lines capable of producing monoclonal antibodies (mAb) against gastric cancer were established. These monoclonal antibodies were used in histopathological diagnosis, cytological and serological diagnosis, and radioimmunoimaging (RII). Also, immunoconjugates and immunoliposomes were produced by linking these antibodies with various anticancer agents. In vitro and in vivo studies in mice were carried out to investigate the possible uses of these antibodies in experimental targeting therapy of gastric cancer. This paper presents a review of these studies.

Inhibition of rat lens aldose reductase by quercetagetin and patuletin

In this paper the results of inhibition of the Aldose reductase (AR) activity on Wistar rat lens by Quercetagetin extracted from Tagetes erects Linn and by Patuletin extracted from Tagetes patula Linn are reported. Quercetagetin inhibited AR of the rat lens by 93.9% at 10(-4) M, 76.0% at 10(-5) M and 13.3% at 10(-6) M. Patuletin inhibited AR of the rat lens by 100% at 10(-1) M, 80% at 10(-5) M and 22.7% at 10(-6) M respectively. The results show that these two flavones are lens AR Inhibitors, but further study should be done for the possibility of clinical application.

Cytogenetic studies on peripheral lymphocytes of members from two multiple familial polyposis coli families

Cytogenetic studies were carried out on peripheral lymphocytes of 30 members from two typical familial polyposis coli (FPC) families. It was found that, under low folic acid culture conditions, the chromosome aberration rate of FPC family members (10%) was much higher than that of the control group (2.3%). No significant difference in SCE was found between the two groups. We suggest that the chromosome aberration rate under certain conditions may be used as a parameter for the early detection of FPC in certain FPC families. The analysis of fragile sites sensitive to low folic acid in FPC family members revealed that besides the significant increase of 3p14, which is frequently seen in tumor patients, other unique sites (1p22, 1p32 and 6q21) were also present in most of the FPC patients. Fragile sites 1p22, 1p32 and 6q21 are located near certain well known oncogene loci; thus, they may have something to do with the pathogenesis of FPC. The actual relationship between these fragile sites and FPC remains to be elucidated.

Capillary refilling (skin turgor) in the assessment of dehydration

This study was undertaken to evaluate the usefulness of skin turgor or capillary refilling in estimating the degree of dehydration in infants with diarrhea. After initial standardization of the technique, capillary filling time was found to be more reproducible when measured in the fingernail bed after applying just the amount of pressure necessary to blanch the nail bed. Capillary refilling time in 30 normal infants 2 to 24 months of age was 0.81 +/- 0.31 seconds. Capillary filling time was then measured in 32 infants with diarrhea admitted to the hospital and correlated to the degree of dehydration as estimated from the difference in weight from the time of hospital admission to the weight after rehydration. A turgor time of 1.5 seconds or less was found to be indicative of a less than 50-mL/kg deficit or of a normal infant; 1.5 to 3.0 seconds suggests a deficit between 50 and 100 mL/kg, and more than 3 seconds suggests a deficit of more than 100 mL/kg.

Correlation between gene expression and chromatin conformation of c-fos and N-ras in human liver and hepatoma

In situ hybridization revealed an apparently higher expression of N-ras and c-fos in human hepatoma than in its adjacent liver tissue. When the isolated nuclei were partially digested with micrococcal nuclease followed by DNA extraction, gel electrophoresis and hybridization with labelled probes, it was shown that in hepatoma the c-fos and N-ras DNA sequences were mainly distributed on the nucleosomes of lower order structures, while these gene sequences in the adjacent liver tissue were found mainly on the nucleosomes of higher order structures. These results clearly indicate a close correlation between gene expression and chromatin conformation of c-fos and N-ras.

Hexokinase, glucose-6-phosphatase dehydrogenase and aldose reductase in human fetal lenses

The lens HK, G6PD, AR activity and its relationship with fetal age was determined. There is a positive correlation between the age of fetus and the activity (IU/mg pro.) of HK and G6PD (r = 0.8069, 0.8204, P < 0.01) and a negative correlation between the age of fetus and activity of AR (r = -0.810 1, 0.05 > P > 0.01).

In vitro effects of fetal bovine serum and glucose on multiplication of Cryptobia salmositica

Cryptobia salmositica multiplied rapidly at 10 C in a minimum essential medium (containing 1.0 mg glucose/ml, Hanks' salts and L-glutamine) supplemented with heat-inactivated fetal bovine serum (FBS) and HEPES buffer (25 mM). The multiplication rate of C. salmositica was related to the amount of FBS; the peak number (approximately 9 x 10(6) parasites/ml) was attained in about 6 wk when the medium contained 25% final concentration of FBS. Glucose utilization was related to the number of parasites; the maximum utilization was reached before peak numbers. Formation of rosette colonies was correlated with multiplication rate and numbers of parasites in cultures. Degenerate round forms found in old cultures probably were caused by the accumulation of metabolic wastes in the medium.

Liquid chromatographic separation of phenothiazines and structurally-related drugs using a beta-cyclodextrin bonded phase column

The retention behaviour of 16 phenothiazines and structurally-related drugs on a beta-cyclodextrin bonded phase column is examined with respect to pH, methanol and TEAA concentrations in the mobile phase, and column temperature. The results are utilized to optimize the separation of these compounds. Both isocratic and gradient-elution separation of the 16 phenothiazine derivatives on the beta-cyclodextrin bonded phase column are investigated. The successful separation of all of the compounds is achieved in the gradient-elution mode.

[A study on atypical scarlet fever]

An analysis of 135 cases of scarlet fever in Harbin Municipal infection hospital in 1987 was carried out. The patients of 0-15 years old were 75.65%, the males were higher than the females. All the patients had atypical clinical manifestation. 45.18% of them were no fever. 30.37% no angina and 40% no strawberry-like tongue. The 60 strains of beta-hemolytic Streptococcus were isolated from 129 cases (positive rate 46.51%). 49 strains of them were identified as Biotype identification was carried out in 28 strains of them. They are all Group A. 14, 6 and 6 strains as biotype 1, 4 and 8/25 respectively. The results of antibiotics resistant test showed that strains which were susceptible to ampicillin and cephalosporin were 81.58% and the strains of resistant penicillin were 21.05%. Some causes of atypical clinical manifestations were discussed.