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Biomedical subjects

Y S Zhang

Publications and source records attributed to Y S Zhang.

At least 19 recordsLinked to original sources
PubMed1997

The infection status of anisakid larvae in marine fish and cephalopods from the Bohai Sea, China and their taxonomical consideration.

The infection status of anisakid larvae was examined in 290 marine fish of 25 species and in 108 cephalopods of 3 species purchased in Bayuquan region, Yingko city nearby the coast of the Bohai Sea from may to August 1992. A total of 7,327 larvae were collected from 156 fish of 19 species and 8 squids of one species. The 3rd-stage larvae of Anisakis simplex were collected from 121 fish (63.4%) of 15 species (N = 191) and from 8 squids (14.8%) of one species (N = 54), and they were total, 5,992 (81.8%). Out of remaining 1,335 larvae, 154 (2.1%) were classified as Thynnascaris type B from 23 fish of 4 species, 1,013 (13.8%) as Thynnascaris type C from 79 fish of 13 species. 164 (2.2%) as Hysterothylacium China type V from 20 fish of 4 species, 3 (0.04%) as Raphidascaris from 3 fish of 2 species and one was Pseudoterranova decipiens larva.

Animals↗
PubMed1997

[Seroprevalence of Helicobacter pylori infection among Yi and Han nationalities in Yunxian County, Yunnan Province].

Under cluster sampling, an early serum essay of helicobacterpylori (Hp) infection among 1084 healthy people, was carried out. Out of them, 325 among the Yi and Han Nationalities at Yunxian County of Yunnan Province were given a simultaneous test of anti-HAV IgG. The results were as follows: overall Hp infection rate was 51.1%; no difference of the infection was observed between the Yis and the Hans; the prevalence of Hp antibody went up with age; Higher rates were detected among those who drank river water or unboiled-water than among those who drank tap water, well water or boiled water, from poultry raisers than from non-poultry raisers and with drug abusers than with non-drug abusers. Hp infection showed a parallel relation to HAV infection. Finally, seven main epidemic factors were sifted from multi-factor logistic analysis namely source of drinking water, drinking habit, chicken-raising, pig-keeping, dog-breeding, drug-abusing and consumption of garlic. All these findings suggested that drinking water was an important vehicle of Hp infection. Our research data seems to have lend support to both fecal- oral transmission viewpoint and the hypothesis that Hp infection derives from animals. Frequent intake of garlic may serve as an agent in long-term prevention of Hp infection among people in this area.

Adolescent↗
PubMed1996

Studies on receptor binding site of insulin: the hydrophobic B12Val can be substituted by hydrophilic thr.

[B12Thr]human insulin and [B12Leu]human insulin were obtained by means of site-directed random mutagenesis. [B12Thr]human insulin retain total biological activity but [B12Leu]human insulin has much lower biological activity. Receptor binding activities of [B12Thr]human insulin and [B12Leu]human insulin are 56% and 3%, respectively, as that of native porcine insulin. The results suggest that the hydrophobic property of the residue side chain at B12 may not be necessary.

Animals↗
PubMed1995

Expression of hepatic metallothionein messenger RNA in feral and caged fish species correlates with muscle mercury levels.

Metallothioneins (MTs) are low-molecular-weight cytosolic proteins that are induced by cellular stress as well as exposure to various heavy metals including mercury. Excessive residues of mercury have recently been identified in various fish species of the lower Ouachita River system in Arkansas. Fillets of mature largemouth bass (Micropterus salmoides) collected from Woodard Lake, an ox-bow lake of the Ouachita River, possessed muscle residues of mercury ranging from 0.3 to 1.0 ppm (micrograms/g). To assess the usefulness of using MT expression as a biomarker of mercury exposure, livers and fillets were obtained from feral bass of Woodard Lake. Ouachita served as a control site having mercury residues below detection. Analyses using a ribonuclease protection assay with winter flounder MT cDNA revealed that bass had significantly elevated levels of MT mRNA which correlated (r2 = 0.756) with the levels of mercury in muscle fillets. To further explore the water quality of Woodard Lake, 10 juvenile channel catfish were housed in cages and placed where feral collections were made in both sites for 2 weeks. Mercury was not detected in muscle or liver and no significant difference in hepatic MT mRNA was observed. These data demonstrate that MT mRNA expression can be used as a tool to assess exposure to heavy metals and suggest that the elevated levels of mercury in large predatory fish may be due to trophic magnification rather than a single point-source exposure.

Animals↗
PubMed1995

The influence of thymectomy on germ-cells of the testis in mice.

We performed thymectomy on the immature and mature male mice and made a quantitative assay of various germ cells of the seminiferous epithelium in the testis with Image Analyser System 35 days following thymectomy. The results indicated that as compared with the control group, all germ cells of the spermatogenesis lineage decreased in the immature group and in the mature group after thymectomy. The present study showed that thymus and its hormone stimulated not only the mitotic division, but also the meiotic division of germ cells during spermatogenesis, suggesting that thymus-sexual axis may play an important role in the process of spermatogenesis in the testis.

Animals↗
PubMed1995

The relationship of Oxalobacter formigenes and calcium oxalate calculi.

The intestinal Oxalobacter Formigenes were isolated in 30 cases of urolithaiasis and in 45 controls. The biologic characters and morphology of the bacteria were also observed. The results showed that the colony counts in urolith group 9 (mean 10(3)/g. faeces) were significantly less than that of controls (mean 10(8)/g. faeces) (P < 0.001). It is believed that the lesser amount of oxalobacter formigenes in urolith was the important factor of the calcium oxalate calculi formation.

Adult↗
PubMed1995

Recombinant A17 Lys human insulin: purification and characterization.

Recombinant A17 Lys human insulin precursor expressed in yeast cells was isolated from the culture medium. After purification, the precursor was converted into A17 Lys human insulin. A17 Lys human insulin can be crystallized but has much lower receptor-binding and biological activities than porcine or human insulin where A17 is Glu. It is proposed that the A17 Glu residue may be involved in the receptor-binding or the active site of human insulin.

Amino Acids↗
PubMed1995

Experience with repair of hypospadias using bladder mucosa in adolescents and adults.

From July 1984 to January 1994, 113 hypospadias operations were performed using a free bladder mucosa graft. There were 31 primary cases and 82 secondary cases in which prior operations had been done. The meatus was penile in 33 patients, penoscrotal in 72 and perineal in 8. The cosmetic and functional results were satisfactory. Postoperative complications included 8 fistulas that required closure and 6 cases of stenosis treated by dilation. Our results suggest that hypospadias repair with a bladder mucosa graft is feasible and reliable. The technique has been performed successfully in the most complex as well as simple cases in adults and adolescents.

Adolescent↗
PubMed1994

Effect of the extracts of pumpkin seeds on the urodynamics of rabbits: an experimental study.

Pumpkin seeds were prepared into oil n-butyle alcohol and ether extracts. The effects of the three extracts on the urodynamics of rabbits were observed. It was concluded that the oil preparation could remarkably reduce the bladder pressure, increase the bladder compliance, reduce the urethral pressure. Other two kinds of preparations had no effect in this experimental. The mechanisms of the effect of oil preparation on the urodynamics and the prospect of clinical use was discussed.

Animals↗
PubMed1994

Time-varying adaptive filters for evoked potential estimation.

Adaptive implementation of an optimal time-varying filter (TVF) for evoked potential (EP) estimation is addressed in this paper. A data-adaptive scheme is used, which converges asymptotically to the optimal TVF solution. Two basic adaptive TVF's (ATVF's) are first introduced, namely least mean square (LMS) ATVF and recursive least-squares (RLS) ATVF. The latter converges much faster than the former. Since the basic ATVF's usually require a relatively large set of response trials to get a meaningful solution, a reduced-order ATVF is further presented and the corresponding LMS and RLS (including a fast RLS) adaptive algorithms are developed. To save memory, a truncated Fourier expansion is suggested to express approximately the time-sequenced weight-vectors of the ATVF's, resulting in a simplified reduced-order ATVF. Finally, extensive simulations are provided to confirm the superior performance of the ATVF's. The present ATVF's can be used as prefilters for latency-corrected average (LCA) processing to obtain more informative estimates of EP signals.

Adult↗
PubMed1994

Peak component latency-corrected average method for evoked potential waveform estimation.

A peak component latency-corrected average (PC-LCA) method consisting of three steps is presented for estimating the evoked potentials (EP) in the human brain. The present PC-LCA is essentially an alternative version of the original LCA method developed by McGillem et al. It first uses a time-varying adaptive filter as a preprocessor to suppress the ongoing EEG and to enhance the EP. Then, the statistics of mean latencies and amplitudes of the EP peak components are estimated by a peak detection and alignment procedure. The final waveform estimate is obtained by superimposing the estimated mean peak components on background information and subsequently fitting a truncated Fourier series using the fast Fourier transform (FFT). Consistent estimates of the EP peak component information are established based on asymptotic analysis of the PC-LCA. Finally, real-time implementation of the PC-LCA is considered, and the superior performance of the PC-LCA method is confirmed by detailed numerical results.

Electroencephalography↗
PubMed1994

The relationship between the energy levels of shock waves and the degree of renal damage after ESWL: a prospective clinical matching trail.

In an attempt to understand the effects of high energy shock wave (HESW) on renal function, we studied prospectively 40 patients with nephrolithiasis in 4 groups, using same voltage with different numbers of shock wave therapy to identify the difference of effects on renal function. Stone burdens and position were similar in these groups. Each group received 1500, 2000, 2500 or 3000 pulses at 12.5 KV on JT-3 lithotripotor respectively. All the groups had significantly increased the levels of urinary NAG, beta 2MG, ALB and serum beta 2MG, which reached the highest values on 1-3 days after ESWL (P < 0.001), and then decreased to the pre-ESWL levels except urinary NAG in group C and D and serum beta 2MG which were still significantly higher (P < 0.05) than those before-ESWL on the 7th day after ESWL. There was significant correlation between either urinary NAG (gamma = 0.977, P < 0.05) or beta 2MG (gamma = 0.933, P < 0.001) with the number of shock wave. In addition, urinary NAG and beta 2MG increased significantly when the number of shock waves was over 2500 shots. These above findings suggest that shock wave had induced acute changes in renal functions and transient renal tubular damages, although these functional changes recovered within one week, and the tubular damage might last longer than 7 days, In order to avoid serious renal damage, it's necessary to limit the energy level of shock waves under 12.5 KV x 2500 shots by using JT-3 lithotriptor.

Acetylglucosaminidase↗
PubMed1993

Effects of thymosin on the secretion of the sexual hormone in rats with experimental varicocele.

Hormonal abnormality in experimental varicocele induced by partial ligation of left renal vein and the effect of thymosin (fraction 5) on the secretion of the sexual hormone were studied in rats. Serum testosterone level was lowered after varicocele formation, but could be reversed or increased by intraperitoneal administration of thymosin 5 mg/rat twice a week for 4 weeks with concomitant increase of testicular testosterone content. Changes in FSH and LH both in serum and testis, determined with immunoassay method as that of testosterone, were insignificant as compared with control or thymosin treated groups.

Animals↗
PubMed1993

Influence of thymosin on the level of cyclic nucleotides in rats with experimental varicocele.

Experimental varicocele was induced by partial ligation of the left renal vein in rats, and the effect of thymosin (fraction 5), a hormone secreted by the thymus, on the level of cyclic nucleotides was investigated. The levels of cAMP and cGMP in plasma and testicular tissue were estimated using radioimmunoassay techniques. The results showed that the level of cAMP in bilateral testicular tissues in rats with experimental varicocele decreased considerably, especially in the left testicular tissue as compared with that in the control group (P < 0.05). 4 weeks after thymosin administration (0.5 mg/rat, twice a week), the level of cAMP in bilateral testicular tissues rose significantly, as compared with that in the experimental varicocele group (P < 0.01). These findings indicate that there exists imbalance in the metabolism of cyclic nucleotides in rats with experimental varicocele. This suggests that the abnormal level of cyclic nucleotides is one of the causes of infertility with varicocele. Since thymosin participates in the metabolism and regulation of cyclic nucleotides, it may have a direct or an indirect effect on the growth and function of reproductive cells.

Animals↗
PubMed1993

[An analysis of the central pathway of vestibulo-sympathetic responses].

In order to elucidate the relationship between several structures of CNS and the vestibulo-sympathetic response (VSR) in rat, the technique of spike triggering average (STA) was used. The spike of the neuron which responded to the pendular rotation (pendular positive unit, PPU) was used to trigger the onset of averaged activities of the splanchnic nerve (SN). Making use of the spike of PPU of nucleus vestibularis medialis (NVM) as an indicator, the SN-STA had a latency of 33.28 +/- 3.1 ms. SN-STA triggered by PPU of reticular formation (RF) of caudal brain stem, a positive response with a latency of 11.13 +/- 0.91 ms was observed. SN-STA triggered by PPU of vestibulocerebellum, a positive response with a latency of 21.86 +/- 1.73 ms was observed. Our results suggest that the nearest supraspinal relay may be the nuclei of medical RF in caudal brain stem and the descending flow of VSR was probably transmitted by the slow conducted fibers of reticulo-spinal tract. According to the latency of SN-STA by PPU of vestibulo-cerebellum, the vestibulcerebellum possibly executed a polysynaptic mission between the transmission of VSR outflow from NVM to RF nuclei of caudal brain stem.

Animals↗
PubMed1992

Inhibitory effect of fluoride on renal stone formation in rats.

The effect of fluorine (F) on stone formation induced by ethylene glycol (EG) was studied in rats. For different groups, the drinking water was supplemented with EG, sodium fluoride (NaF), EG+NaF, or nothing as control. An isotope-tracing method was used to evaluate experimental stone formation in the kidneys by introducing 45Ca intraperitoneally into rats and then measuring the radioactivity of the kidney. At the end of the 4-week experiment, rats of the EG+NaF group showed a significantly lower incidence of gross urinary stones and lower 45Ca activity in their kidneys compared to the EG group of rats. Both the EG group and EG+NaF group had markedly increased urinary oxalate excretion, with the latter significantly lower than the former (p less than 0.05). Urinary oxalate excretion was relatively lower in the NaF group than in the control group. This study indicates that NaF can inhibit renal stone formation induced by EG by decreasing oxalate synthesis and urinary oxalate excretion, and suggests a possible clinical therapeutic value of NaF in the prevention of oxalate kidney stones.

Animals↗
PubMed1991

Initial purification and characterization of hepatic microsomal cytochrome P-450 from BNF-treated perch (Perca fluviatilis).

1. A procedure was developed for isolating and purifying cytochrome P-450 from hepatic microsomes of BNF-treated perch, using modified versions of the methods of Williams and Buhler (1982. Biochim. biophys. Acta 717, 398-404) and Goksøyr (1985. Biochim. biophys. Acta 850, 409-417). 2. Following chromatography on phenyl-Sepharose CL 4B and DEAE-Sepharose CL-6B, the major peaks, fractions b and c, were resolved into five fractions, possibly representing different isoenzymes, by a FPLC with a strong anion exchange column (Mono Q). 3. These fractions have been characterized on the basis of their spectral, electrophoretic and immunological properties. 4. The purified form of cytochrome P-450 in fraction V from perch liver showed a number of similarities to cytochrome P-450c, the major BNF-inducible cytochrome P-450 in cod liver. 5. Therefore we suggest that this purified form of cytochrome P-450 is a BNF-induced form in perch and that it is closely related to the gene subfamily cytochrome P-450 IA1.

Animals↗