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B Zhu

Publications and source records attributed to B Zhu.

17 recordsLinked to original sources
PubMed1992

Large serotonin-like immunoreactive amacrine cells in the retina of developing Xenopus laevis.

The earliest appearance of serotonin-like immunoreactivity (SLI) in different cell types and the development of large SLI amacrine cells were studied in the retina of Xenopus laevis from stage 33/34 to adult. Intense SLI was first found in the somas of large amacrine cells at stage 39. The somas of small amacrine cells showed weak SLI at stage 41, followed by bipolar cells at stage 43. The number of large SLI amacrine cells in the inner nuclear layer of the retina increased from 57 at stage 40 to 774 in adult. Over the same period, retinal area increased from 0.19 mm2 to 24.57 mm2 with an accompanying decrease of cell density from 301/mm2 to 32/mm2. in adult animals large SLI amacrine cells were non-uniformly distributed. Peak cell density of 50-60/mm2 was located in the center of the ventrotemporal quadrant and a trough of 8-15/mm2 in the dorsal periphery of the retina. Peak cell density region of the adult retina corresponded to part of the retina formed at early developmental stages where the rate of cell generation of large SLI amacrine cells was higher. These observations indicate that (1) SLI is expressed first by large amacrine cells, followed by small amacrine and bipolar cells; (2) large SLI amacrine cells are generated continuously throughout life, (3) the non-uniform retinal distribution of large cells results from a spatio-temporally differential cell generation at the ciliary margin.

Animals↗
PubMed1992

Synaptic contacts of tyrosine hydroxylase-immunoreactive elements in the inner plexiform layer of the retina of Bufo marinus.

Tyrosine hydroxylase (TH) immunocytochemistry was utilized to quantify dopaminergic synapses in the inner plexiform layer of the retina of Bufo marinus. Since dopaminergic cells have bistratified dendritic arborisation in the inner plexiform layer, attention was given to the segregation of synapses between the scleral and the vitreal sublaminae. Light-microscopically, a more elaborate dendritic branching was observed in the scleral than in the vitreal sublamina. In contrast, about 55% of synapses occurred in the vitreal one fifth of the inner plexiform layer, 30% in the scleral fifth, and 15% in the intermediate laminae. Input sources and output targets showed only minor quantitative differences between sublaminae 1 and 5. TH-immunoreactive processes were found in presynaptic (62.8%) and postsynaptic (37.2%) positions. Synapses to the stained dendrites derived from bipolar (40.4%) and amacrine (59.6%) cells, whereas outputs from the TH-positive processes were directed to amacrine cells (56.8%) and to small and medium-sized dendrites (35.4%); at least some of these can be considered as ganglion cell dendrites. TH-positive profiles neither formed synapses with each other nor were presynaptic to bipolar cell terminals. Junctional appositions of the immunoreactive profiles were occasionally seen on non-stained amacrine and ganglion cell dendrites in the scleral sublamina of the inner plexiform layer and on optic axons in the optic fibre layer. Although dopaminergic cells are mainly involved in amacrine-amacrine interactions, inputs from bipolar terminals and outputs to ganglion cell dendrites were also substantial, suggestive of a role also in vertical information processing.

Animals↗
PubMed1992

Stability of fusarin C: effects of the normal cooking procedure used in China and pH.

Fusarin C (FC) is a naturally occurring mutagen found on Fusarium moniliforme-contaminated corn. In Linxian, China, an area of exceptionally high incidence of esophageal cancer, the milled corn is made into small cakes called wotou, which are steamed. It has been suggested that FC may play a role in the etiology of esophageal cancer, but this has been questioned, in part, because of the thermal instability of FC. We therefore measured the effects of temperature on FC stability, mimicking the cooking process. FC was extracted from the wotou and quantitated by both reverse-phase high-performance liquid chromatography and the Ames assay. After wotou were steamed for 30 minutes, 11% and 3% of the initial FC remained, as detected by the two assays, respectively. The milled corn, when moistened with water, had a pH of 6.1, which was lowered to 5.3 when it was inoculated with F. moniliforme and cultured for three weeks. Pickled vegetables are sometimes added to the wotou, which further reduces the pH. To determine the effects of pH on FC, it was heated in solution, with the pH varied between 4 and 8. Its stability was very pH dependent, decomposing more rapidly as the pH increased. Because ingested FC would also be subjected to the low pH of the stomach, it was treated for 30 minutes at 37 degrees C and pH values ranging from 1.0 to 7.0. FC was stable (less than 15% decomposition) under these conditions. If FC is a significant health threat, it could most easily be destroyed by cooking at slightly basic pH values.

China↗
PubMed1992

[Genetic profile of LIBP/1 inbred strain derived from the Kunming outbred stock of the mouse].

To make the genetic profile of the LIBP/1 inbred strain obtained from Kunming mice, the most widely used outbred stock in China, 26 loci were examined. The genotypes of four kinds of coat color genes were a/a, B/B, c/c and D/D. The results of testing 21 biochemical marker genes showed Akp-1b, Amy-1a, Car-2a, Ce-2a, Es-1b, Es-3a, Es-10a, Es-11a, Gpd-1a, Gpi-1a, Gus-1b, Hbbs, Idh-1a, Ldr-1a, Mod-1a, Mup-1b, Pep-3b, Pgm-a, Sep-1b, Tam-1c, and Trfb. The H-2 gene loci were Kb and Db.

Animals↗
PubMed1992

[Detection of estrogen receptors (ER) in gastric cancer].

Using Avidn-biotin-peroxidase complex (ABC) immunohistochemical method, 68 gastric cancer specimens and 20 non-cancerous stomach specimens were examined for ER. In 38 of 68 gastric cancer specimens, ER concentrations were also biochemically determined by Dextran-coated charcoal (DCC) assay. The results showed that ER was absent in noncancerous stomach tissues. ER was present in 21 (30.9%) of gastric cancers. The ER positive cases were chiefly poorly differentiated gastric cancers. There were no significant statistical differences in the patient's age or sex, size of primary tumor and the ER positive rates. The results indicate that endocrine therapy might be useful for the ER positive gastric cancer patients.

Adenocarcinoma↗
PubMed1992

Cloning and partial sequencing of the porcine growth hormone (pGH) gene from pituitary gland.

High molecular weight DNA was isolated from porcine pituitary gland, and a genomic library was constructed using lambda EMBL3 as cloning vector. Five positive clones were identified by in-situ hybridization with the full-length pGH cDNA as the probe. Dot-blot hybridization, restriction analysis, and Southern hybridization showed that one of the positive clones contained the entire pGH gene. A subclone that contained the upstream sequence from the SmaI site of pGH gene was identified, and part of it was sequenced. We also compared the sequence of our pGH gene with the corresponding sequence of the published pGH gene.

Amino Acid Sequence↗
PubMed1990

Dendritic morphology and retinal distribution of tyrosine hydroxylase-like immunoreactive amacrine cells in Bufo marinus.

Tyrosine hydroxylase-like immunoreactive (TH-IR) amacrine cells (ACs) in the retina of metamorphosing and adult Bufo marinus were visualized, and their retinal distribution established, using immunohistochemistry on retinal wholemount and sectioned material. The somata of TH-IR ACs were located in the innermost part of the inner nuclear layer (INL). Their dendrites branched predominantly in the scleral sublamina of the inner plexiform layer (IPL), with sparse branching also in the vitreal sublamina. In the retinae of metamorphosing animals 592 +/- 113 (mean +/- S.D.) immunoreactive cells and in adult 5,670 +/- 528 cells were found. Usually 1, 2 or 3 stem dendrites arose from the somata of TH-IR cells which branched 2 or 3 times. In the adult retinae the dendritic field sizes of immunoreactive cells were in the range of 0.059 +/- 0.012 mm2, which resulted in a considerable dendritic overlap across the retina. TH-IR cells were unevenly distributed over the retina, with 72 cells/mm2 in the central temporal retina, 45-50 cells/mm2 along the naso-temporal axis of the retina and 25 cells/mm2 in the dorsal and ventral peripheral retina. The average density was 36 +/- 6 cells/mm2. A considerable number of TH-IR cells (range 52-133, n = 4) were displaced into the ganglion cell layer (GCL) of the retina. The mean soma sizes of immunoreactive cells were significantly higher in the low density (95 +/- 13 microns 2) than in the high cell density areas (86 +/- 12 microns 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Amplification on the Amycolatopsis (Nocardia) mediterranei plasmid pMEA100: sequence similarities to actinomycete att sites.

An amplification of a 2.0-kb fragment was found on the plasmid pMEA100 isolated from a subculture of the wild-type strain LBG A3136 of Amycolatopsis (Nocardia) mediterranei. Plasmid preparations contained a mixture of molecules with copy numbers of the amplified unit in the range of 2 to 10. The amplification on pMEA100 was stable; propagation of cells for many generations did not change the pattern of the amplified DNA. Fragments of the plasmids containing the amplifiable unit of DNA (AUD) and the amplified DNA sequence (ADS) were subcloned and characterized. Sequencing of the AUD terminal regions and the junction between ADS units showed that the amplifiable unit of DNA was flanked by 12-bp direct repeats. The DNA segments adjacent to the 12-bp sequence common to the left and right AUD terminal regions also showed significant similarities. In addition, the left AUD terminal region flanking the 12-bp repeat exhibited considerable sequence similarity to actinomycete plasmid attachment sites, particularly to the pMEA 100 att site.

Actinomycetales↗
PubMed1990

[Mutagenesis of vitamin B2 producer by using protoplasts].

Studies on preparation, regeneration and ultraviolet-mutagenesis of protoplasts of vitamin B2 producer Eremothecium aohbyii were reported. By using a complex enzyme system (0.5% snial digestase + 0.5% cellulase), a great number of protoplasts were obtained. Ultraviolet-mutagenesising positive mutation ratio is 14.29%. The HPLC analysis indicated that a lot of mutants were screened by using ultraviolet-mutagenesis mutation of protoplasts, Vitamin B2 produced by the mutant E3 increased 116.4%.

Mutation↗
PubMedDate not supplied

Serotonin synthesis and accumulation by neurons of the anuran retina.

Serotonin-synthesizing and serotonin-accumulating neurons were studied in the retinas of Xenopus laevis and Bufo marinus. All previously identified cell types exhibiting serotonin-like immunoreactivity (SLI) were labeled by intravitreal injection of 5,7-dihydroxytryptamine (5,7-DHT). They included two amacrine cell types (large and small) in both species, and one bipolar cell type in Xenopus. Incubation of retinas in culture medium in the ambient light reduced SLI in amacrine cells and enhanced the labeling in bipolar cells. After incubation, some photoreceptor cell bodies and large numbers of outer segments also displayed SLI in both species. Incubation with the serotonin-uptake inhibitor, fluoxetine, reduced immunolabeling in bipolar cells and outer segments to the level in the untreated retinas. Both large SLI and 5,7-DHT-accumulating amacrine cells in Xenopus and Bufo were labeled with an antibody raised against phenylalanine hydroxylase (PH), which binds to tryptophan 5-hydroxylase, one of the synthesizing enzymes for serotonin. Small SLI and 5,7-DHT-accumulating amacrine cells in both species represented two populations, one with and the other without PH-like immunoreactivity (PH-LI). The anti-PH antibody failed to label any SLI or 5,7-DHT-accumulating bipolar cells in Xenopus. These observations indicate that all large and some small SLI amacrine cells in the retinas of Xenopus and Bufo synthesize serotonin, while other small SLI amacrine, bipolar and photoreceptor cell bodies, and outer segments only accumulate serotonin.

5,7-Dihydroxytryptamine↗