[DNase I sensitivity of nucleus and chromatin in six different tissues of old rates]

In order to investigate the mechanism of aging, we studied the DNase I sensitivity of nucleus and chromatin in six different tissue (heart, liver, spleen, lung, kidney and brain of old and weanling wistar rats. The results showed that the DNase I digestive sensitivity levels of nucleus and chromatin in the tissue of the old rats were lower than those of the weanling rats respectively that in the old rats, the DNase I digestive sensitively in the tissue varied, the lowest sensitivity was in brain (P < 0.01); and that in the weanling rats, lowest DNase I digestive sensitivity of nucleus and chromatin was also in the brain, but the difference was not significant.

[Determination of nifedipine content and its uniformity in tablets by high performance liquid chromatography]

An HPLC method with diazepam as internal standard was developed to determine nifedipine content and its uniformity in tablets. The analytical column was a C18 column, the mobile phase consisted of V (methanol):V(triethylamine, pH 5.20) = 68:32. The detection was carried out with UV detector (lambda = 237 nm). Under this condition, the linear range was wide(8-80 mg/L) and the recovery was high (99.86%). The proposed method is simple and accurate and the decomposed product can be separated as well. Therefore, the quality of nifedipine tablets can be effectively controlled.

In situ light-scattering measurements of morphologically evolving flame-synthesized oxide nanoaggregates

Nonspherical Al2O3 aggregates produced in a laminar counterflow nonpremixed methane flame were investigated with an in situ laser light-scattering (LLS) technique in combination with a thermophoretic sampling-transmission electron microscope (TS-TEM) method. These flame-synthesized nanoparticles clearly underwent morphological changes following their formation (from precursor trimethylaluminum hydrolysis), mainly as a result of aggregation and sintering processes in the approximately 3.3 x 10(4) K/s heating environment. To characterize this particulate morphological evolution conveniently we made multiangular absolute LLS measurements and interpreted them based on the Rayleigh-Debye-Gans scattering theory for fractal aggregates. Optically determined fractal dimension D(f), mean radius of gyration, aggregate size distribution, and local particle volume fraction phi(p) were found to be consistent with our independent ex situ TS-TEM experiments. D(f) (optically inferred) increased from 1.60 to 1.84 with axial position, confirming the morphological evolution of alumina aggregates owing to finite-rate, spatially resolved high-temperature sintering. An extension of our TS-TEM method was successfully applied, for the first time to our knowledge, to inorganic particles. Phi(p) inferred by means of this ex situ technique generally agreed with that from the in situ LLS technique, supporting our interpretation of both measurements. Moreover, an optically inferred net sintering rate of alumina aggregates approaching the flame was estimated to be consistent with the available TEM data. The LLS methods and results presented here are expected to permit more comprehensive mechanistic analyses of nanoaggregate sintering and coagulation kinetics in such flame environments, ultimately improving the modeling of more-complex (e.g., turbulent, high-pressure) combustion systems involving nanoparticle formation and evolution.

Identification and characterization of immunoreactive calcitonin gene-related peptide from lymphocytes of the rat

There is accumulating evidence that the immune system can produce neuropeptides. In the light of these facts, we obtained direct evidences to prove that T lymphocytes also synthesize and secrete calcitonin gene-related peptide (CGRP), a neuropeptide localized within primary sensory nerves. By using CGRP specific RIA, CGRP-like immunoreactivity (LI) was found in the extracts of rat lymphocytes from thymus and mesenteric lymph node. The intracellular concentration of lymphocyte-derived CGRP-LI of rat thymus and mesenteric lymph node was 745+/-39 and 447+/-33 fg/10(6) cells, respectively. CGRP-LI in lymphocytes was shown to co-elute with synthetic rat CGRP and sensory neuron-derived CGRP by reverse-phase HPLC. In addition, the CGRP-LI located in the T lymphocytes was also shown by immunocytochemical method examined by electron microscopy. The CGRP mRNA detected by RT-PCR was also present in these lymphocytes and was also identified to be the same one in sensory neurons. These data suggest that CGRP is synthesized and secreted in T lymphocytes of both thymus and lymph node in the rat, and this is identified to be the same one in neuronal tissue. Lymphocyte-derived CGRP may act in an autocrine/paracrine mode and play an important role in certain physiological and pathophysiological conditions.

Suicide effect on rat gliomas mediated by recombinant adenovirus thymidine kinase/acyclovir system

OBJECTIVE

To establish the replicated-deficient recombinant adenovirus-mediated thymidine kinase/acyclovir (Adtk/ACV) system and to evaluate its suicide effect on rat C6 brain gliomas in vitro and in vivo.

METHODS

The plasmid pAdtk and pJM17 were co-infected into 293 cells (adenovector packaging cells) and the results were identified by polymerase chain reaction (PCR) assay. After the glioma C6 cells were transduced by Adtk at different multiplicity of infection (MOI) and exposed to different concentrations of ACV or gancyclovir (GCV), the cell survival curves were studied, and the cell surface was observed with scanning electronic microscopy (SEM). C6 gliomas in vivo at different inoculation days were injected with Adtk intratumorally and ACV intraperitoneally daily, and the survival duration and histologic changes of the rats were observed.

RESULTS

The infectious Adtk virions had a suicide effect which was enhanced with the increase in MOIs of Adtk and ACV doses along with bystander effect. Under scanning electronic microscope, special pathologic changes were observed. ACV had a similar effect as GCV but a higher dose was used. The survival duration in day 3, day 6 and day 8 groups exceeded 90 days, and the rats in day 10 group survived 28.5 +/- 4.6 days, but the survival duration in untreated C6 group and AdLacZ/ACV (adenovirus-mediated LacZ/ACV) treated group were 16.8 +/- 3.1 and 14.0 +/- 2.2 days respectively.

CONCLUSION

Adtk/ACV system can effectively kill the rat brain gliomas in vitro and in vivo.

Phase transitions in the growth of C3H 10T1/2 cells

In systems used to express transformation using focus formation as the end point, nontransformed cells generally express a down-regulation of cell growth and division made evident by the formation of a monolayer of cells that completely covers the growth surface. In C3H 10T1/2 cells, down-regulation is thought to be progressively effected principally by cell-to-cell communication via gap junctions. Starting with a sparse population in asynchronous growth--e.g. containing cells in all phases of the growth cycle--as the area density increases, cells are progressively lost from the distribution in the order M phase, G2 phase, S phase and G1 phase, leading to the accumulation of viable cells out of cycle in so-called G0 phase. We have measured the progressive phase transitions as a function of inoculum size and time. The influence of a promoter and an antipromoter was also examined as well as the expression of the cyclin/cyclin-dependent kinase inhibitors p21Waf1/Cip1 and p27Kip1 as the cells grew into confluence. Using cells synchronized in mitosis, we found that with increasing cell density the expression of p27 increased and concomitantly p21 decreased.

[Follow-up on hepatitis B immunized neonates born to HBsAg positive mothers]

OBJECTIVE

To determine the immune persistence in neonates born to hepatitis B surface antigen (HBsAg) positive mothers with different schedules for HB immunization.

METHODS

Two hundred and three neonates born to HBsAg positive mothers were immunized at birth with HB vaccine in different schedules and doses, and followed-up for six years continuously for antibodies against HBs (anti-HBs) and carriage status of HBsAg.

RESULTS

Prevalence of anti-HBs in the neonates kept in more than 90% during the six years since immunization, with a peak at the ages of seven to twelve months and decreasing by 48.82% at the ages of one to two years. Their anti-HBs kept relative stable during two to six years of age. Eight children converted to anti-HBs negative for three to five years still kept uninfected. Fourteen children converted to anti-HBs negative reconverted positive again one to two years later. No single chronic carrier with HBsAg was found in them.

CONCLUSION

A booster dose of HB vaccine seems unnecessary for children in six to ten years after primary immunization.

Vaginal mucosal immunization for recurrent urinary tract infection: phase II clinical trial

PURPOSE

Decreased local immunity to uropathogenic bacteria may be a factor predisposing women to recurrent urinary tract infections. Our phase I study demonstrated the safety of a multi-strain vaccine administered as a vaginal suppository. A phase II study was conducted to determine vaccine efficacy.

MATERIALS AND METHODS

A total of 91 women susceptible to recurrent urinary tract infections was entered into the study and the courses were analyzed in a randomized, double-blind, placebo controlled trial of vaginal mucosal immunization. Subjects received 3 vaginal suppositories at weekly intervals. Depending on the treatment group each suppository contained 1 of 2 vaccine doses or suppository material only. Each patient was followed for 5 months to record infection episodes, and obtain urine, vaginal irrigates and serum to measure immunological responses.

RESULTS

Immunogen treated women who were off antibiotic prophylaxis throughout the study had a significant delay in interval to reinfection during the first 8 weeks compared to women receiving placebo. Mean interval until reinfection was delayed from 8.7 weeks for placebo treated to 13 weeks for vaccine treated women. Immunological responses in serum, urine and vaginal fluid were variable. No serious adverse effects were observed.

CONCLUSIONS

These data demonstrate that vaginal mucosal immunization can enhance resistance to urinary tract infections in susceptible patients.

The RNA binding domain of ribosomal protein L11 is structurally similar to homeodomains

The RNA binding domain of ribosomal protein L11 is strikingly similar to the homeodomain class of eukaryotic DNA binding proteins: it contains three alpha-helices that superimpose with homeodomain alpha-helices, and some conserved residues required for rRNA recognition align with homeodomain helix III residues contacting DNA bases.

[Pharmacological effects of zisu and baisu]

The extract and volatile oil of zisu (Perilla frutescens) has shown significant antipyretic effect in rabbits and antiemetic effect in pigeons. The fatty oil extracted from its seeds has significant antitussive effect in mice and anti-asthmatic effect in guinea pigs. The extract, volatile oil and fatty oil of Baisu, which is of the same genus as Zisu have the same effects as those of Zisu. The acute toxicities of the extract and fatty oil of Zisu and Baisu, whether by peroral or by intraperitoneal, are similar to each other. These results indicate that Baisu has the same pharmacological effects as Zisu, and thus can be used as a substitute for Zisu.

In vivo actions of insulin-like growth factor-I (IGF-I) on cerebellum development in transgenic mice: evidence that IGF-I increases proliferation of granule cell progenitors

The in vivo actions of insulin-like growth factor-I (IGF-I) on cerebellum development have been investigated in transgenic (Tg) mice (IGF-II/I Tg mice) in whom an IGF-II promoter-driven IGF-I transgene is highly expressed in cerebellum. Compared to normal littermates, the brains of IGF-II/I Tg mice exhibited overgrowth beginning from the second week of postnatal life. Among the brain regions examined, cerebellum exhibited the greatest increase in size, such that by 50 days of age cerebellar weight and DNA content were increased by 90% and 143%, respectively, compared to littermate controls. Morphological studies of adult IGF-II/I Tg mice showed that the total number of granule and Purkinje cells was increased by 82% and 20%, respectively, findings consistent with the increased cerebellar DNA content and indicating that the increased cerebellar weight was due in part to an increase in cell number. The thickness of the molecular layer also was increased in IGF-II/I Tg mice. During early postnatal development the number of external granular layer cells, as well as the number of BrdU labeled external granular cells, was increased. These data strongly indicate that IGF-I increases granule cell number by a mechanism that involves the stimulation of granule cell progenitor proliferation. Our findings also indicate that IGF-I influences the growth of Purkinje cells and possibly of other cell types in the cerebellum.

Reproducibility of an esophageal biopsy sampling procedure in a high-incidence area for esophageal cancer in northern China

The objective of this study was to evaluate the reproducibility of the biopsy sampling procedure in research on esophageal lesions. Biopsies were taken from the middle and lower thirds of the esophagus, one from each site, from 25 subjects in a high-incidence area for esophageal cancer in Xinye County of Henan Province, China. The biopsy sampling procedure was repeated on the same subjects 10 days later. When the biopsies were analyzed together and those with worse pathologies were used for diagnosis, 52% of the subjects had the same grade of lesions in the second biopsy examination, 32% had lower-grade lesions, and 16% had higher-grade lesions.