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Z H Jin

Publications and source records attributed to Z H Jin.

At least 19 recordsLinked to original sources
PubMed2002

Production of teicoplanin by valine analogue-resistant mutant strains of Actinoplanes teichomyceticus.

Teicoplanin is a glycopeptide antibiotic produced by Actinoplanes teichomyceticus. A strain improvement to increase the productivity of the major component, teicoplanin A2-2, was carried out. As the fatty moiety of teicoplanin A2-2 is derived from L-valine, L-valine analogue (valine hydroxamate)-resistant mutants were derived. One of the mutants, 98-1-227, overproduced valine and produced a higher titer of total teicoplanin with higher A2-2 content. In a pilot fermentor (7 m3), the total productivity of teicoplanin was 1,800 units/ml and the A2-2 content was 58%.

Actinomycetales↗
PubMed2001

Melting mechanisms at the limit of superheating.

The atomic-scale details during melting of a surface-free Lennard-Jones crystal were monitored using molecular dynamics simulations. Melting occurs when the superheated crystal spontaneously generates a sufficiently large number of spatially correlated destabilized particles that simultaneously satisfy the Lindemann and Born instability criteria. The accumulation and coalescence of these internal local lattice instabilities constitute the primary mechanism for homogeneous melt nucleation inside the crystal, in lieu of surface nucleation for equilibrium melting. The vibrational and elastic lattice instability criteria as well as the homogeneous nucleation theory all coincide in determining the superheating limit.

Journal Article↗
PubMed2001

Modification of thermosensitivity and chemosensitivity induced by combined treatments with hyperthermia and adriamycin.

Both adriamycin (ADM) and hyperthermia show thermal chemo-enhancement. Tolerance induction against ADM in heated cells has been reported resulting in clinical difficulty of cancer therapy. We investigated thermo-enhancement induced with ADM (0.2 microg/ml) treatment alone or combined with ADM and 42 degrees C hyperthermia in Chinese hamster V79 cells in vitro. Intracellular accumulation of hsc70 and hsp72 proteins after hyperthermia or ADM was observed to examine the possible relationship between cell killing effect and their accumulations. Thermosensitivity of V79 cells at 42 degrees C after the simultaneous treatments with ADM showed marked thermo-enhancement within the short-term treatments for less than 1 h, while the combined treatments for longer than 1 h, the cells showed reduced thermosensitivity. Survival from the simultaneous treatments for less than 1 h was reduced markedly less than the single treatment both with ADM or 42 degrees C hyperthermia alone. Thermotolerance was markedly induced in a step-up hyperthermia (42 degrees C 2 h-44 degrees C). The combined treatments with ADM and 44 degrees C hyperthermia following the 42 degrees C preheating alone does not inhibit thermotolerance development. The combined treatments with ADM and 42 degrees C preheating showed markedly interactive cell killing, but no thermo-enhancement to the following 44 degrees C hyperthermia was shown. The leveling slope of the 44 degrees C heating period-survival curve was drawn. In the Western blot analyses, hsc70 existed constitutively in the V79 cells. Following the 42 or 44 degrees C hyperthermia alone, intracellular accumulation of hsp72 was determined. ADM treatment alone did not induce any accumulation of hsp72. In the simultaneous treatments with ADM and hyperthermia, the accumulation of hsp72 was markedly reduced. The accumulation of hsp72 after the combined treatment with ADM and hyperthermia was not observed as markedly as that after hyperthermia alone.

Adaptation, Physiological↗
PubMed2000

A case of combined nevus: compound nevus and spindle cell Spitz nevus.

Combined nevi consisting of a Spitz nevus and an acquired nevus are unusual, and, to our knowledge, the combination of a spindle cell Spitz nevus and an overlying compound nevus has not been previously reported. We report a 17-year-old girl with a nodule on the left anterior lower extremity. The nodule was asymptomatic, firm, brown, symmetrical, dome-shaped, 8 mm in diameter, and not found with ulceration. Histological findings showed proliferation of spindle-shaped cells with an overlying compound nevus. The spindle-shaped cells were large, non-pigmented, uniform in size and shape, with rare mitoses and without nuclear atypia, and arranged in a storiform pattern in thick collagen bundles. They stained positively for S-100 and negatively for HMB-45. The lesion was considered to be a new type of combined nevus consisting of a spindle cell Spitz nevus and an overlying compound nevus.

Adolescent↗
PubMed2000

Combination effect of photodynamic and sonodynamic therapy on experimental skin squamous cell carcinoma in C3H/HeN mice.

We studied a combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT) for improving tumoricidal effects in a transplantable mouse squamous cell carcinoma (SCC) model. Two sensitizers were utilized: the pheophorbide-a derivative PH-1126, which is a newly developed photosensitizer, and the gallium porphyrin analogue ATX-70, a commonly used sonosensitizer. Mice were injected with either PH-1126 or ATX-70 i.p. at doses of 5 or 10 mg/kg.bw. At 24 (ATX-70) or 36 hr (PH-1126) (time of optimum drug concentration in the tumor) after injection, SCCs underwent laser light irradiation (88 J/cm2 of 575 nm for ATX-70; 44J/cm2 of 650 nm for PH-1126) (PDT), ultrasound irradiation (0.51 W/cm2 at 1.0 MHz for 10 minutes) (SDT), or a combination of the two treatments. The combination of PDT and SDT using either PH-1126 or ATX-70 as a sensitizer resulted in significantly improved inhibition of tumor growth (92-98%) (additive effect) as compared to either single treatment (27-77%). The combination using PH-1126 resulted in 25% of the treated mice being tumor free at 20 days after treatment. Moreover, the median survival period (from irradiation to death) of PDT + SDT-treated mice (> 120 days) was significantly greater than that in single treatment groups (77-95 days). Histological changes revealed that combination therapy could induce tumor necrosis 2-3 times as deep as in either of the single modalities. The combination of PDT and SDT could be very useful for treatment of non-superficial or nodular tumors.

Animals↗
PubMed1995

[Effects of sennosides, rhubarb polysaccharides and emodin on the cytoplasmic free calcium in isolated rat brain cells].

Free intracellular Ca2+ ([Ca2+]i) levels in rat brain were measured by Ca(2+)-sensitive fluorescent indicator Fura-2/Am and the effects of sennoside (SEN), polysaccharides from Rheum palmatum (RPP) and emodin (EMD) were studied. Results showed that the resting [Ca2+]i level in the brain cells was 176.25 +/- 44.67 nmol.L-1 (n = 10) in Ca(2+)-free Hank's solution containing EGTA 0.5 mmol.L-1. After adding CaCl2 (2 mmol.L-1) and KCl (120 mmol.L-1) to the brain cells suspension sequentially, the free [Ca2+]i levels were obviously elevated (P < 0.01) compared with that of resting level. The brain cells were pretreated with SEN (0.07, 0.37 mmol.L-1) for 10 min. In the resting or using the above doses of CaCl2 and KCl, the [Ca2+]i were obviously decreased compared with the control groups (P < 0.01) at the same conditions. RPP dose-dependently decreased the [Ca2+]i. On the contrary, when brain cells were pretreated with EMD (0.037 mmol.L-1) for 10 min, the [Ca2+]i were obviously increased compared with the control groups (P < 0.01) at the same conditions. The results showed that EMD could not only promote the release of intracellular Ca2+ but also the influx of extracellular Ca2+. The opposite effects of the different active components of rhubarb on the [Ca2+]i levels suggest that rhubarb may have different kinds of regulatory functions on brain cells.

Animals↗
PubMed1995

[A seroepidemiological study on hepatitis D virus (HDV) infection in Henan Province, China].

In order to investigate the distribution of HDV infection in Henan province, a seroepidemiological study on HDV infection was conducted. A total number of 1182 HBsAg positive serum samples was collected from 13 prefectures and cities between 1991 and 1993. HDV markers (HDAg, anti-HDV, anti-HDV-IgM) were tested with Enzyme Linked Immunosorbant Assay (ELISA). The prevalence rates of HDAg, anti-HDV, anti-HDV-IgM and HDV infection rate were 3.0%, 3.5%, 3.5% and 8.1%, respectively. There were no statistically significant differences in the prevalence rates of HDV infection in patients of different sexes but significant differences in the prevalence rates of HDV infection in patients of different ages, especially in age group above 60, were noticed. We also noticed that the infection rates of HDV were 8.7%, 4.6%, 7.7%, 6.3%, 11.9% and 0.0% in the groups of HBsAg carriers, acute hepatitis, chronic active hepatitis, chronic persistent hepatitis, liver cirrhosis and severe hepatitis, respectively. These findings indicated that HDV infection was important in the pathogenesis of chronic hepatitis B and in the exacerbation from liver disease to cirrhosis.

Adolescent↗
PubMed1994

[Study on effect of emodin on the isolated intestinal smooth muscle of guinea-pigs].

Emodin is an active principle of Rheum palmatum. It is reported that emodin possesses antibiotic and antineoplastic functions. The effect of emodin action on the isolated intestinal smooth muscle of guinea-pigs were dose dependent. When the dose of emodin was less than 29.6 mumol/L, the contraction effect enhanced obviously with increasing dosage; but whenever the dose increased to more than 29.6 mumol/L, on the contrary, the effect decreased gradually and ceased finally. Emodin with appropriate concentration (14.8 mumol/L) strengthened the effect of acetylcholine (Ach) on the isolated ileum and large intestine of guinea-pigs (P < 0.05 and P < 0.01). But high concentration of emodin could reduce even completely antagonize the effect of Ach. Under such condition, CaCl2 could restore the effect of Ach on the smooth muscle. It is suggested that emodin has biphasic regulatory effect on the intestinal smooth muscle, and its effect is related to calcium ion.

Animals↗
PubMed1994

[Liver and ductal remnants of porta hepatis in biliary atresia: histopathology and clinical significance].

We studied the relationship between the histopathology of biliary atresia and its clinical significance. Liver biopsies were made in 30 patients and ductal remnants of porta hepatis were studied in 20. The criteria for the pathological diagnosis of hepatic fibrosis were described. We think that judging the severity of hepatic fibrosis may be useful in selecting the mode of Kasai's operation and estimating the prognosis of patients with biliary atresia.

Biliary Atresia↗
PubMed1990

Development-specific genes and their expression at the RNA level.

A total of seven clones, which are specific for the development of carrot somatic embryo cells, were constructed and screened from the cDNA expression library of phage lambda gt11. The purification of plaques, isolation of DNA from the phages, digestion of the clone's DNA with EcoRI restriction enzyme, identification of the inserts on the agarose gel by electrophoresis and subcloning of cDNA inserts from phage lambda gt11 vector into plasmid pIBI or pUC18 were performed respectively. The data of cross hybridization by Southern blot analysis indicated that clones 16,22,50 and 60 are new cDNA genes. In addition, the new cDNA genes tissue-specific expression on variety organs in the carrot plant, such as flower, petiole, leaf and root, as well as time-course expression in callus and embryo cells of different culture periods were determined through Northern blot analysis. The results suggested that the corresponding gene for clone 22 is a specific gene which is regulated by development and closely associated with carrot somatic embryogenesis.

Blotting, Northern↗
PubMed1990

A study on the life-cycle and epidemiology of Pseudanoplocephala crawfordi Baylis, 1927.

A study of the life-cycle and epidemiology of Pseudanoplocephala crawfordi Baylis, 1927 is reported. Intermediate hosts are Tenebrio obscurus, T. molitor, Carpophilus dimidiatus and Tribolium castaneum. The first three species are new host records. Development in the intermediate host takes 1-1.5 months. The completion of the life-cycle takes 2-2.5 months. Surveys of intermediate hosts, pigs, humans and rats were carried out. In Rattus norvegicus, the prevalence was as high as 22%. Epidemiological factors and suggestions for control measures are discussed.

Animals↗
PubMed1988

Developmental regulation of embryonic genes in plants.

Somatic embryogenesis from cultured carrot cells progresses through successive morphogenetic stages termed globular, heart, and torpedo. To understand the molecular mechanisms underlying plant embryogenesis, we isolated two genes differentially expressed during embryo development. The expression of these two genes is associated with heart-stage embryogenesis. By altering the culture conditions and examining their expressions in a developmental variant cell line, we found that these genes were controlled by the developmental program of embryogenesis and were not directly regulated by 2,4-dichlorophenoxyacetic acid, the growth regulator that promotes unorganized growth of cultured cells and suppresses embryo morphogenesis. These genes are also expressed in carrot zygotic embryos but not in seedlings or mature plants.

Journal Article↗