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Biomedical subjects

B Zhou

Publications and source records attributed to B Zhou.

At least 109 records · Page 6Linked to original sources
PubMed1999

[A large-scale study on the safety and epidemiological efficacy of Japanese encephalitis (JE) live vaccine (SA14-14-2) in the JE endemic areas].

OBJECTIVE: To measure the safety and epidemiological efficacy of Japanese encephalitis live vaccine(SA14-14-2). METHODS: Guoyang and Mengcheng counties in Anhui Province, were chosen as observed spots where high incidence of JE was noticed in China. 1-6 years old children in two counties were inoculated with vaccine manufactured by Chengdu Biological Products Institute in the beginning of 1992. All children of 1-6 years old received one primary dose of live vaccine and the children at one or two years old were respectively given one dose for primary or booster vaccination in 1993-1996. Side effects of live vaccine had been under surveillance for five years for its safety JE cases during the epidemic season (Jun to October), were diagnosed clinically and serologically. RESULTS: Data on the safety and efficacy of the JE live vaccine(SA14-14-2) are listed as follows:1) During 1992-1996, a total number, of 335,941 children at 1-6 year old were vaccinated. No vaccine-associated encephalitis, meningitis or other serious adverse events were observed. 2) The incidence of JE case has greatly declined since the beginning of large-scale vaccination. The average JE morbidity dcreased from 11.34/100,000 in 1987-1991 to 2.74/100,000 in 1992-1996(P < 0.005). 3) The incidence of JE case in 1-6 years old in that period reduced as well. The average JE morbidity decreased from 56.24/100,000 to 13.83/100,000 in Guoyang and from 44.57/100,000 to 16.94/100,000 in Mengcheng counties respectively(P < 0.005). Most of the JE cases (94%) occurred in the unvaccinated children including all the 18 death cases. 4) Serum antibody response to immunization were measured by plaque reduction neutralization test. Neutralizing antibody seroconversion after one single vaccination were 83.87%-94.74%. CONCLUSION: The results further confirmed that JE live vaccine is safe for children and effective for prevention from JE disease in JE endemic areas.

Antibodies, Viral↗
PubMed1999

A fast, sensitive and specific method for rice dwarf virus detection by northern blot hybridization.

Based on stability of double-stranded (ds) RNA, a new, fast, sensitive, and specific method for detection of genomic rice dwarf virus (RDV) dsRNA by molecular hybridization was developed. In contrary to the commonly used, standard Northern blot analysis, dsRNA is denatured in the immobilized state on the blot. Therefore, risk of degradation of single-stranded (ss) RNA by ribonuclease (RNase) during sample preparation, electrophoresis and blotting is eliminated. This method overcomes disadvantage of incomplete denaturation of dsRNA in Northern blot analysis. In conclusion, the newly developed method is reliable, sensitive, very specific, and gives a low background. The entire procedure is also less time consuming; it can be completed within 2-3 days. The new method may be regarded as a modification of the standard Northern blot analysis.

Blotting, Northern↗
PubMed1999

[Prediction of the outcome of dysplasia of esophageal epithelium by high resolution image analysis].

OBJECTIVE: To predict the outcome of dysplasia of esophageal epithelium by means of high resolution image analysis(HRIA). METHODS: Asymptomatic adults were examined for balloon cytology of the esophagus in 1983 from Heshun Commune of Linxian County. Ninety three cases of severe dysplasia and 122 cases of mild dysplasia of the esophagus were selected for this study. By means of an Axiomat-microscope equipped with TV-camera, 100 normal nuclei of well-preserved cells in the intermediate layer of Pap-stained squamous epithelium were randomly examined. RESULTS: Of the 93 cytologically diagnosed severe dysplasia cases, 24, 14 and 7 progressed to carcinoma in 3, 5 and 9 years, respectively. In the other 48 cases, dysplasia remained stable or regressed to normal. The other cases were used as the control. According to chromatin features, correct diagnosis of cases was achieved by HRIA in 75.0%(18/24), 85.7%(12/14) and 85.7%(6/7) of the cases examined, respectively (P < 0.001). Of the 122 cytologically diagnosed mild dysplasia, 16, 13 and 12 cases progressed to carcinoma in 3, 5 and 9 years, respectively. The other 81 cases remained stable or regressed to normal. Correct diagnosis was made by HRIA in 93.8%(15/16), 76.9%(10/13) and 83.3%(10/12) of the cases examined, respectively (P < 0.001). CONCLUSION: Chromatin nuclear features examined by HRIA can predict the outcome of precancerous lesions and discriminate progressor from non-progressor ones. It can be used as surrogate endpoint biomarkers for the evaluation of efficacy of chemoprevention trial.

Adult↗
PubMed1999

[Preparation of collagen-based materials for wound dressing].

This article addressed the methods to develop collagen-based materials for wound dressing. Fresh frozen bovine tendon was treated with 0.05 M acetic acid at pH 3.2 for 48-72 h, then it was homogenized, filtered, and after the process of adding chondroitin sulphate(8%), it was dbubblized; thus 1.5%-2.5% collagen solution was finally prepared. The solution was lyophilized in prefrozen or un-prefrozen mold. The collagen sponge was crosslinked with 0.25% glutaraldehyde for 24 h. Three other wound dressings were developed by similar method, namely collagen membrane with polyurethane membrane onlay, polyurethane-coated collagen membrane and collagen membrane on gauze. It was demonstrated that the property of frozen bovine tendon was stable, and the prepared collagen sponge contained pores of 50-400 microns in diameter. Some factors influencing pore structure and size in the collagen sponge were discussed. The results of this preliminary study suggested that the collagen could be used as wound dressing.

Animals↗
PubMed1999

[Research into simultaneous determination of five components by ridge regression spectrophotometry].

Ridge regression spectrophotometry (LHG) is one of the computational spectrophotometry developed recently. It is used in this paper to the analysis of five component s--acetaminophen, p -aminophenol. p -nitrophenol. p -acetaminophenol acetic acid ester and p -nitrophenol acetic acid ester. The choose of medium and the determination of the amount of mixed standard solution were described in detail. The experimental results show that in the medium of 0.1 mol x L(-1) HCI, the recovery ratio of each component ranges from 95.5% to 106.1% and the RSD ranges from 0.8% to 9.8%. This approach is simple and suitable for the computer-aid analysis. The approach has been used to the analysis of the sample in the course of synthetic acetaminophen.

English Abstract↗
PubMed1999

[Research into determination of tricomponent sample by ridge regression spectrophotometry].

In this paper ridge regression spectrophotometry was used to analyze three components--Acetaminophen, P-Ni-trophenol and P-Aminophenol with absolute ethanol as the solvent. The basic principle and analytical steps of the method were described in detail. The experimental results show that the recovery of each component ranges from 99.24% to 101.31% with the medium of absolute ethanol. As compared with conventional methods, this method is simple, rapid and suitable for computer-aid analysis.

Acetaminophen↗
PubMed1998

Conformational features of a truncated staphylococcal nuclease R (SNR135) and their implications for catalysis.

Conformational features of a truncated (14 amino acid residues deleted from the C-terminus) staphylococcal nuclease R (SNR135) and the ternary complex of SNR135-Ca2+-pdTp were studied using circular dichroism (CD) spectra and 1-anilinonaphthalene-8-sulfonate (ANS)-binding fluorescence spectra under different conditions. Kinetic parameters such as KDNAM, KDNAS, KCaM, KCaA, and KpdTpd of SNR135 were also determined. The results show that SNR135 contains some residual secondary structure and some tertiary structure elements as indicated by far-UV and near-UV CD spectra and that it has the ability to fold into a native-like state in the presence of pdTp and Ca2+, but there are obvious differences both in secondary structure and in tertiary structure between the SNR135-Ca2+-pdTp complex and SNase R. The unfolding curves in Gdn-HCl show that the stability of the native-like conformation of the SNR135-Ca2+-pdTp complex is much less than that of SNase R though the ligand (Ca2+, pdTp) binding increases the stability of the SNR135-Ca2+-pdTp complex to some extent. Comparison of the kinetic parameters of SNR135 with those of the full-length nuclease shows that both SNR135 and SNase R have the same value of KpdTpd and very similar values of KCaM and KCaA, but SNR135 has larger values of KDNAM and KDNAS than SNase R. Such results indicate that the C-terminal deletion for SNR135 does not greatly affect the ligand (Ca2+, pdTp) binding and decreases the binding affinity of the DNA substrate to the nuclease, implying that the amino acid residues at the ligand binding sites in SNR135 are probably arranged in a similar topology to those in SNase R and that effective binding of the DNA substrate to the enzyme needs the conformational integrity of the entire enzyme molecule. Furthermore, it is suggested that the binding sites of pdTp and DNA substrate may overlap but are not exactly the same. This paper also provides evidence obtained by monitoring ANS-binding fluorescence that the partially unfolded conformation of SNR135 is not in the molten globule state.

Calcium↗
PubMed1998

Juvenile hormone prevents ecdysteroid-induced expression of broad complex RNAs in the epidermis of the tobacco hornworm, Manduca sexta.

A cDNA homolog of the Drosophila melanogaster Broad Complex (BRC) gene was isolated from the tobacco hornworm, Manduca sexta, which shows a predicted 88% amino acid identity with Drosophila BRC in the N-terminal BTB domain. Three zinc finger domains encoding homologs of the Drosophila Z2, Z3, and Z4 domains (93, 100, and 85% identity, respectively) were obtained by RT-PCR. In Manduca dorsal abdominal epidermis, BRC RNAs were not observed during the larval molt. Three BRC transcripts-6.0, 7.0, and 9.0 kb-first appeared at the end of the feeding stage of the fifth (final) instar when the epidermis is exposed to ecdysteroids in the absence of juvenile hormone (JH) and becomes committed to pupal differentiation. These RNAs were induced in day 2 fifth larval epidermis in vitro by 20-hydroxyecdysone (20E) in the absence of JH with dose-response and time courses similar to the induction of pupal commitment. This induction by 20E in vitro was prevented by the presence of JH I at levels seen in vivo during the larval molt. In the wing discs, the BRC RNAs appeared shortly after ecdysis to the fifth instar and coincided with the onset of metamorphic competence of these discs. Application of a JH analogue pyriproxifen during the fourth instar molt delayed and reduced the levels of BRC mRNAs seen in the wing discs in the early fifth instar, but did not completely prevent their appearance in this tissue that first differentiates at metamorphosis. The expression of the BRC transcription factors thus appears to be one of the first molecular indications of the genetic reprogramming of the epidermis necessary for insect metamorphosis. How JH prevents BRC expression in this epidermis may provide the key to understanding how this hormone controls metamorphosis.

Amino Acid Sequence↗
PubMed1998

Microtubule involvement in translational regulation of fibronectin expression by light chain 3 of microtubule-associated protein 1 in vascular smooth muscle cells.

Our previous studies suggested that enhanced fibronectin mRNA translation in ductus arteriosus compared with aortic smooth muscle cells is related to increased expression of light chain 3 (LC3) of microtubule-associated protein 1, which binds an AU-rich element in the 3' untranslated region of fibronectin mRNA. We therefore hypothesized that microtubules are involved in LC3-mediated fibronectin mRNA translational regulation. In this study we show that disruption of microtubules by colchicine inhibits fibronectin mRNA translation in cultured ductus arteriosus smooth muscle cells. We proposed that the mechanism might be related to decreased docking of fibronectin mRNA on the translational machinery, ie, membrane-bound polysomes on rough endoplasmic reticulum, and confirmed this by Northern blot analysis. To investigate the mechanism further, we carried out polysome analysis using sucrose gradient centrifugation and fractionation and studied the polysomal distribution of fibronectin mRNA and LC3 protein in the sucrose gradient by using RNase protection assay and Western immunoblotting, respectively. Colchicine treatment shifts fibronectin mRNA from the fractions containing membrane-bound polysomes to the fractions carrying free polysomes and concomitantly decreases the amount of LC3 protein in the fractions containing membrane-bound polysomes. Furthermore, an EDTA-release experiment demonstrates that LC3 protein associates with the 60S ribosomal subunit. Our data support the concept that microtubules may function with LC3 to facilitate sorting of fibronectin mRNA onto rough endoplasmic reticulum and translation.

Animals↗
PubMed1998

Mucosal iodine staining improves endoscopic visualization of squamous dysplasia and squamous cell carcinoma of the esophagus in Linxian, China.

BACKGROUND: In previous studies in the high risk population of Linxian, China, the majority of foci of high grade (moderate and severe) squamous dysplasia (HGD) and invasive squamous carcinoma (CA) of the esophagus were associated with endoscopically visible lesions that could be targeted for biopsy, but some foci of HGD were missed by routine endoscopic examination. This study examined whether spraying the mucosa with Lugol's iodine solution, which stains normal epithelium brown but leaves dysplasia and carcinoma unstained, could improve endoscopic detection and delineation of these lesions. METHODS: Two hundred twenty-five Linxian adults with balloon cytologic evidence of dysplasia or carcinoma underwent endoscopy. All visible lesions were described and photographed before and after staining with 1.2% Lugol's iodine solution. Biopsies were taken from all lesions visible before staining, from all unstained lesions (USLs) after applying the stain, and from representative control areas of stained mucosa. RESULTS: Two hundred fifty-three USLs and 255 control sites were biopsied. No complications occurred. Ninety-four biopsy sites contained HGD and 20 contained CA. Before staining, the sensitivity of visible lesions for identifying HGD or CA was 62%, and the specificity was 79%. After staining, the sensitivity of USLs for identifying HGD or CA was 96%, and the specificity was 63%. Eighty-eight percent of the HGD and CA lesions were larger or more clearly defined after staining. The diagnostic lesions in 17 of 31 patients with moderate dysplasia (55%), 8 of 35 patients with severe dysplasia (23%), and none of the 19 patients with invasive carcinoma (0%) were identified only after staining. CONCLUSIONS: Mucosal iodine staining improved endoscopic detection and delineation of HGD and CA in these patients. This simple technique is highly sensitive for identifying these precursor and invasive squamous lesions, and it should be used whenever optimal visualization of squamous mucosal abnormalities is required.

Adult↗
PubMed1998

Regulation of the transcription factor E75 by 20-hydroxyecdysone and juvenile hormone in the epidermis of the tobacco hornworm, Manduca sexta, during larval molting and metamorphosis.

The homolog of the ecdysteroid-induced transcription factor E75A in Drosophila melanogaster was cloned from the tobacco hornworm, Manduca sexta, and its developmental expression and hormonal regulation were analyzed. Both E75A and E75B mRNAs were found in the abdominal epidermis during both the larval and the pupal molts, with E75A appearing before E75B, coincident with the rise of ecdysteroid. Exposure of either fourth or fifth instar epidermis to 20E in vitro caused the rapid, transient induction of E75A RNA with a peak at 6 and 3 h, respectively, followed by maintenance at low levels until 24 h. Epidermis from fourth instar larvae with high endogenous juvenile hormone (JH) showed a 10-fold higher sensitivity to 20E (EC50 = 2 x 10(-8) M for fourth instar and 2 x 10(-7) M for fifth instar epidermis). The presence of the protein synthesis inhibitor anisomycin had no effect on the induction but prevented the decline, indicating that E75A RNA was directly induced by 20E, but its down-regulation depended on protein synthesis. Exposure of day 2 fifth instar epidermis to 20E in the presence of JH I, which prevents the 20E-induced pupal commitment, caused an increased accumulation of E75A RNA throughout the culture period although the temporal pattern was unaffected. These findings show for the first time that JH plays a role in 20E-induced early gene expression and suggest that the higher levels of E75A may be required for maintenance of larval commitment of this epidermis.

Amino Acid Sequence↗
PubMed1998

A simple and sensitive ribonucleotide reductase assay.

Ribonucleotide reductase (RR) is a key regulatory enzyme in the DNA synthesis pathway and is the target of the cancer chemotherapeutic agent hydroxyurea. The study of RR is significantly hindered by the tedious and labor-intensive nature of enzymatic assay. In this report, we present a novel RR assay in which detection of the deoxyribonucleotides produced by RR occurs via coupling to the DNA polymerase reaction, and is enhanced by using RNase to degrade endogenous RNA. Cell extracts from various cell lines were treated with RNase and then reacted with ATP and radioactive ribonucleotide diphosphate as the substrate. Incorporation of the radioactive substrate [14C]CDP into DNA was linear over 30 min and was linear with the amount of extract, which provided RR activity. The reaction was inhibited by hydroxyurea and required Mg2+ and ATP, suggesting that the assay is specific to RR activity. While RR activities determined by our method and by a conventional method were comparable, this novel method proved to be simpler, faster, more sensitive and less expensive. In addition, assay of the RR activity for multiple samples can easily be performed simultaneously. It is superior to other RR assays in all aspects.

Calibration↗
PubMed1998

Effect of low HDL combined with hypertriglyceridemia in coronary artery disease patients on PGI2 biological activity in relation to lipid regulating treatment.

The purpose of this study was to investigate the effect of low high-density-lipoprotein (HDL) combined with hypertriglyceridemia in coronary artery disease (CAD) patients on prostaglandin I2 (PGI2) biological activity in relation to lipid regulating treatment. The inhibitory rate of PGI2 on ADP-induced platelet aggregation was used as the index for PGI2 biological activity. Twenty health individuals served as normal controls. CAD group consisted of 20 patients with low HDL combined with hypertriglyceridemia. The results showed that, before the treatment, the stabilizing effect on PGI2 activity decreased significantly in CAD group when compared with the control group (P < 0.01). One month after the treatment, HDL level in CAD group increased significantly and TG level significantly decreased (P < 0.001). The different effect on PGI2 activity was no longer found between CAD group and control group (P > 0.05), further confirming the protecting effect of HDL on PGI2 biological activity. Low HDL is considered as an important risk factor of CAD, therefore, impaired PGI2 biological activity and increased platelet aggregation might be responsible mechanisms. Furthermore, raising HDL level by lipid regulating treatment could restore the protective effect of HDL on PGI2 and might be helpful in the prevention of the acute coronary syndrome.

Coronary Disease↗
PubMed1998

Folding of SNase R begins early during synthesis: the conformational feature of two short N-terminal fragments of staphylococcal nuclease R.

To further understand the folding of nascent peptide during the early course of peptide synthesis, two short N-terminal fragments of staphylococcal nuclease R (SNase R), SNR52 and SNR79, were made by deleting 97 and 70 amino acid residues from the C-terminus. The conformations of SNR52 and SNR79 were studied by FTIR and far-ultraviolet CD. The results demonstrate that even the short N-terminal fragments of SNase R still have a certain amount of residual ordered secondary structure in the physiological condition. The ordered secondary structures were mainly assigned as beta-strands and turns, which corresponds well to the structures of the N-terminal part in the native protein. The conformational changes during unfolding and refolding in different concentrations of guanidine hydrochloride (GuHCl), monitored by far-ultraviolet CD and intrinsic fluorescence, show that the interaction between amino acid residues, which governs the formation of their conformation are not random. Considered together with earlier studies (Jing et al., Biochim Biophys Acta 1995;1250:189-196; Zhou et al., J Biochem 1996:120: 881-888), the results suggest that the folding of nascent peptide chains begins early in the synthesis process and that the amount of ordered structure increases with increasing peptide chain length until the conformation of the biologically active protein is generated.

Circular Dichroism↗
PubMed1998

Expression of mRNA for type IV collagen alpha1, alpha5 and alpha6 chains by cultured dermal fibroblasts from patients with X-linked Alport syndrome.

COL4A5 mutations causing X-linked Alport syndrome (XLAS) are frequently associated with absence of the alpha3, alpha4,alpha5 and alpha6 chains of type IV collagen from basement membranes and increased amounts of the alpha1(IV) and alpha2(IV) chains in glomerular basement membrane. Although many COL4A5 mutations have been described in XLAS, the mechanisms by which these mutations influence the basement membrane appearance of chains other than alpha5(IV) remain poorly understood. In this study, we used dermal fibroblasts from eight normal individuals and nine males with XLAS to test the hypotheses that COL4A5 mutations increase transcription of COL4A1 and suppress transcription of COL4A6. Ribonuclease protection assays revealed that alpha1(IV), alpha5(IV) and alpha6(IV) transcripts were expressed in cultures of dermal fibroblasts. The mRNA levels for alpha1(IV) in eight of nine patients with XLAS were not increased compared to controls; one patient with a large COL4A5 deletion showed significant elevation of alpha1(IV) mRNA levels. No differences in steady-state mRNA levels for alpha6(IV) were found when XLAS fibroblasts were compared with controls, even though little or no alpha6(IV) protein was detectable at the dermal-epidermal junction by immunofluorescence study. This finding suggests that post-transcriptional events account for the absence of alpha6(IV) in the Alport dermal-epidermal junction.

Adolescent↗
PubMed1998

Ligamento-muscular protective reflex in the lumbar spine of the feline.

A ligamento-muscular protective reflex in the lumbar spine was demonstrated in a feline model. Stimulating electrodes were applied to the supraspinous ligament between several lumbar vertebra (L1 to L6) while recording myoelectric discharge from the paraspinal muscles at the L3, L4 and L5, bilaterally. Electromyographic (EMG) activity was present in the paraspinal muscles bilaterally, upon stimulation of the supraspinous ligament, in six preparations. The EMG discharge was strongest in the muscles one level below that of the stimulated ligament, whereas weaker EMG signals were recorded from as far as two levels above and below. The mean time delay between the application of the stimulus to the ligament to the resulting EMG ranged from 2.52 to 2.77 ms at all levels. Stimulation of the supraspinous ligament in the L6 segment resulted in a weak reflex response, and stimulation in the L7 segment did not produce any EMG activity. It was concluded that mechanoreceptors in the supraspinous ligament at the L1/6 levels may initiate sensory signals upon strain of the ligament, during flexion. This, in turn, causes contraction of the paraspinal muscles, bilaterally, to extend the spine and prevent possible damage to the ligament while maintaining stability. The results may add to the understanding of low back pain, and to the formulation of surgical procedures which could spare the neural supply of the ligament, allowing advanced physiotherapeutic modalities to be implemented for post-surgical rehabilitation.

Animals↗
PubMed1998

Efficacy of orchidopexy on spermatogenesis in the immature mutant 'trans-scrotal' rat as a cryptorchid model by quantitative cytological analysis.

OBJECTIVES: To determine whether cryptorchidism is a congenital malformation and whether the impaired spermatogenesis in immature testes can be reversed by early orchidopexy, using the mutant trans-scrotal (T-S) rat which is normally masculinized but has cryptorchidism in 85% of males. MATERIALS AND METHODS: First, T-S rats (six per group) with ectopic testes destined to be undescended were investigated histologically at 4, 7 and 14 days after birth. Secondly, 12-day-old T-S rats were divided into four groups which underwent different procedures, i.e. 1, with normally descending testes (normal control, 10 rats); 2, with undescended testes (UDT) treated by orchidopexy (treated UDT, eight rats); 3, with UDT treated by a sham operation (sham-operated UDT, six rats); and 4, with UDT left untreated (untreated UDT, six rats). Thirty days after operation the testicular anatomy was recorded; excised testes were examined histologically and different types of germ cells were counted per tubule cross-section microscopically. RESULTS: There were no quantitative or morphological differences in the numbers of gonocytes, type-A spermatogonia or Leydig cells in the seminiferous tubules between normal and ectopic testes in the first 14 days after birth. However, by 21 days of age spermatogenesis in the UDT had declined with transformation from primary leptotene spermatocytes to spermatids. There were significantly more Leydig cells in the untreated UDT at 30 days than in normal control testes. The impaired spermatogenesis in UDT was restored by early orchidopexy and there were significantly more seminiferous tubules at stage 3 (pachytene spermatocytes) and stage 4 (spermatids) than in the untreated or sham-operated groups (P < 0.001). CONCLUSIONS: These results show that in the T-S rat with cryptorchidism, the testicular damage is not a congenital malformation and can be reversed with early surgical correction.

Animals↗