Biomedical subjects
Publications and source records attributed to Y He.
The contents of four alkaloids in different processed products of Strychnos nux-vomica hamely, vomicine, icajine, strychnine N-oxide and brucine N-oxide, were determined by TLC-densitometry. The relationship between alkaloid contents and processing methods was studied.
Corneal neovascularization (CNV) was induced by alkali burn injuries in 20 rabbit corneas. The process of CNV was observed with biomicroscopy in vivo and histologically by light and electron microscopy. At 8 hours after injury, an obvious acute inflammatory response as evidenced by infiltration of neutrophils had already occurred in the pericorneal limbal area. Many neutrophils in the extravascular space contained abundant intracytoplasmic phagolysosomes. The vascular sprouts appeared 2 days after injury. The infiltration of neutrophils and their debris were visible around newly formed blood vessels in the cornea. The results suggest that there be the participation and an inductive action of neutrophils in the pathogenesis of CNV.
Metronidazole ester, a new nitroimidazole drug, was synthesized by the Department of Physical Chemistry, School of Pharmacy, Shanghai Medical University. The trichomonadicidal and amoebicidal activity of metronidazole ester was evaluated in vitro by the cultivation of Trichomonas vaginalis and Entamoeba histolytica at different drug concentrations. The results indicated that the 100% lethal concentration for T. vaginalis and E. histolytica was 2.6 micrograms/ml and 40 micrograms/ml, respectively after incubation with metronidazole ester for 48 h. In comparison with metronidazole, the effect of metronidazole ester for both protozoa was similar.
Nested RT-PCR, done by using degenerated primer pair, was used to detect hepatitis C virus RNA (HCV RNA) in serum, plasma, liver and peripheral blood leukocytes (PBLC) of 30 patients with acute and chronic posttransfusion hepatitis C and 7 asymptomatic anti-HCV positive subjects. The results showed that the percentage of positive HCV RNA in PBLC, including both the plus and minus strands, in patients with chronic hepatitis C was significantly higher than that in acute hepatitis C and asymptomatic anti-HCV positive subjects (P < 0.05-0.001). All the 7 asymptomatic anti-HCV positive subjects did not have detectable minus strand of HCV RNA in their PBLC, serum or plasma. In 17 patients who had liver histologic examination, the positive rate of both strands of HCV RNA in PBLC of acute hepatitis (AH) was lower than that of chronic active hepatitis (CAH) (P < 0.05). Both strands of HCV RNA were detected in the liver of one AH and 6 CAH patients. The present data confirmed that PBLC of patients with hepatitis C were indeed infected by HCV. The longer the infection time, the more the chance of PBLC being infected by HCV. Patients with active liver disease (CAH) had usually higher positive rate of minus strands of HCV RNA in PBLC. In the serum and plasma of all the 37 cases, minus strand of HCV RNA was not detected and the positive rate of the plus strand of HCV RNA in their serum and plasma was similar. Futhermore, the positive rate of both plus and minus strands of HCV RNA in PBLC of 30 patients with chronic hepatitis C was also similar. It is suggested that HCV not only may infect PBLC, but also replicate in PBLC and that the occurrence of minus strand of HCV RNA is associated with activity of liver disease.
This paper deals with a HPLC method for determining the content of gamma-schizandrin in Manganbao granules. Samples are extracted with haxane, re-dissolved in MeOH, chromatographed on HPLC (Column, Spheri-5 RP-18, 220 mm x 4. 6mm, mobile phase, 75% MeOH) and the main components can be easily isolated. Six samples were analyzed by calibration curve method. The results have shown that the quantitative analysis of gamma-schizandrin conducted in this way is convenient, fast and highly reproducible.
To investigate the effective way and dosage of intravas deferens injection of HFMC for male contraception, Teflon tubes of 1 mm caliber were used to imitate intravas injection of HFMC. We injected HFMC first, then the precipitant; thus HFMC could adhere to the walls and blend with the precipitant to precipitate. Eight adult male rabbits, exposed reproductive ducts were injected with dyed HFMC in opposite directions (upward and downward), HFMC flowed out of the distal end of the vas easily when its volume was more than that of the vas. 14 adult rabbits were used for the comparison of sperm density and fertility index between upward and downward injections of HFMC, and between the dosage of HFMC (50 microliters and 100 microliters) injected upward. The results show that it is difficult to attain contraception by intravas injection of HFMC downward, but contraception is quite possible by intravas injection of HFMC upward providing the volume is enough. The result also suggest that HFMC should be injected into vas deferens upward first; its volume should be 3 time as much as the natural volume of the vas from the injecting point to the epididymal end. Then a little precipitant is injected into the vas.
Ligands which activate neuronal nicotinic acetylcholine receptors (nAChRs) represent a potential approach for the palliative treatment for the symptoms of memory loss associated with Alzheimer's disease (AD). Based upon this approach, a series of novel 3,5-disubstituted isoxazoles and isothiazoles were prepared and evaluated in vitro as cholinergic channel activators (ChCAs) of neuronal nAChRs. Many of the 3-substituted 5-(2-pyrrolidinyl)isoxazoles were found to have nanomolar binding affinities comparable to (S)-nicotine (2a) in a preparation of whole rat brain. However, in a paradigm measuring the evoked release of [3H]dopamine from a preparation of rat striatum, there were differences in the agonist potencies and efficacies of these analogues relative to 2a. The differences in agonist potency observed between compounds of comparable binding potency may be due to differences in ligand interactions with various subtypes of neuronal nAChRs.
Cholesteatoma of the middle ear is a relatively common disorder, often with severe consequences. Histologically, the aggressively growing, bone-destructing form shows papillary growth and koilocytosis, which are characteristic of papillomavirus-induced lesions. A PCR (polymerase chain reaction) method using degenerate primers for the detection of any known or as yet unknown HPV (human papillomavirus) type was applied in screening 51 biopsies from 42 patients. A resulting 36% (16/45) of the cholesteatomas were found to contain papillomavirus DNA, which hybridized under stringent conditions with an HPV-II DNA probe. In 3 cases the presence of HPV-II DNA could be confirmed by sequencing the PCR products. The mere presence of this HPV DNA does not prove an etiological role of this group of viruses in the induction of cholesteatomas. It does, however, identify another group of human proliferative lesions putatively linked to papillomavirus infections.
Exposure of ornithine decarboxylase (ODC; L-ornithine carboxy-lyase, EC 4.1.1.17)-overproducing mouse FM3A cells to micromolar levels of spermine or spermidine caused abnormal accumulation and toxicity of polyamines. This was apparently due to the inefficiency of negative feedback control of polyamine transport by polyamines in ODC-overproducing cells. Since antizyme is the only protein thus far recognized that can interact with ODC, depletion of free antizyme was regarded as the reason for the abnormal accumulation of polyamines. Accordingly, ODC-overproducing cells were transfected with pMAMneoZ1 possessing rat antizyme cDNA under the control of a glucocorticoid-inducible promoter. In the transfected cells, the addition of dexamethasone caused an increase in the amount of antizyme with an apparent molecular mass of 27 kDa, a decrease in the amount of ODC, a decrease in the polyamine transport activity, and the recovery of growth inhibition or cell death. The results indicate that antizyme can regulate not only the amount of ODC but also the activity of polyamine transport.
Effects of antizyme on polyamine transport and spermine restoration of the growth of polyamine-deficient cells were examined by using mouse FM3A cells transfected with pMAMneoZ1 possessing rat antizyme cDNA under the control of glucocorticoid-inducible promoter. Treatments of the transfected cells with alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase (ODC), and dexamethasone, an inducer of antizyme, both caused a decrease in ODC activity and polyamine contents and inhibition of cell growth. However, spermine uptake of the transfected cells was repressed by dexamethasone but stimulated by DFMO. The decrease in the rate of spermine uptake in dexamethasone-treated cells was attributed to an increase in Km value and a slight decrease in Vmax value. Accordingly, restoration of cell growth by spermine was less effective in dexamethasone-treated cells than DFMO-treated cells. These results clearly indicate that antizyme has dual functions: one for ODC degradation and the other for negative regulation of polyamine transport.
Deposition of large quantities of amyloid substance in the walls of the cerebral vessels and in the core of the senile plaques is characteristic of Alzheimer's disease. beta A4 peptide, the main component of the amyloid substance, is a product of a larger amyloid precursor protein which has the structure of a transmembrane receptor and is widely distributed throughout the body. The pathway leading to beta A4 is not yet fully established but could involve lysosomal degradation. It has been suggested that the beta A4 peptide is of neuronal or vascular origin. The beta A4 peptide is found in diffuse deposits in the cortex and cerebellum as well as in the basal ganglia before the classic senile plaques appear, mainly in layer III of the cerebral cortex. These diffuse deposits are devoid of degenerating neurites (i.e. containing abnormally phosphorylated tau protein). The classical senile plaques contain numerous degenerating neurites linking them to the connective network of the cortex. The intellectual deficit is correlated significantly to the density of the classical senile plaques but not to the density of the diffuse deposits. Although a mutation of the gene coding for the beta A4 peptide appears to be sufficient to induce (or accelerate) Alzheimer's disease, this is undoubtedly an exceptional mechanism. Certain mutations involving the beta A4 precursor protein gene increase in vitro the production of beta A4. The molecular and morphological steps leading, from the accumulation of the peptide (which in itself has no clinical expression) to the neurofibrillary pathology of the senile plaques and of the neurones (which are strongly correlated with clinical dementia), remain hypothetical.
Twelve site-directed mutants of rat cytochrome P450 2B1 distributed over seven positions and four putative substrate recognition sites (SRS) were constructed and expressed in COS cells. Function was examined using androstenedione and testosterone as substrates. Substitutions at positions 303, 360, and 473 did not markedly affect the regio- or stereoselectivity of androgen metabolism, whereas mutants in positions 206 (SRS-2), 302 (SRS-4), and 363 and 367 (SRS-5) exhibited markedly different steroid metabolite profiles compared with parental P450 2B1. In particular, the Phe-206-->Leu substitution conferred androgen 6 alpha- and testosterone 7 alpha-hydroxylase activities, and the Thr-302-->Ser substitution suppressed androgen 16 beta-hydroxylation in favor of androstenedione 16 alpha- and testosterone 15 alpha-hydroxylation. Replacement of Val-363 or Val-367 with Ala conferred androgen 15 alpha-hydroxylase and 6 beta-hydroxylase activities, respectively, and suppressed susceptibility to mechanism-based inactivation by the P450 2B1-selective chloramphenicol analog N-(2-p-nitrophenethyl)chlorofluoroacetamide. The Val-367-->Ala mutant was also resistant to chloramphenicol itself. The Leu mutant at position 363 exhibited increased specificity for androstenedione and testosterone 16 beta-hydroxylation, whereas the Leu mutant at position 367 exhibited decreased stereospecificity. Most interestingly, the size of key residues identified plays a critical role in governing steroid hydroxylation from the alpha-face or beta-face and hydroxylation on the D-ring or the B-ring.(ABSTRACT TRUNCATED AT 250 WORDS)
The antiproliferating effect of nine kinds of bis(ethyl)polyamine analogues [three kinds each of bis(ethyl)triamine, bis(ethyl)tetraamine and bis(ethyl)pentaamine] was compared using FM3A cells. The inhibitory effect was in the order BE4444 > BE3443 > BE4334 > or = BE444 > BE343 > BE333 > BE44 > BE34 > BE33. Our results indicate that not only polyamine deficiency but also the accumulation of polyamine analogues is involved in the inhibition of cell growth. Accumulation of bis(ethyl)polyamine analogues caused the inhibition of protein synthesis and the decrease in the ATP content. The protein synthetic system in mitochondria was more strongly inhibited by bis(ethyl)polyamine analogues than that in the cytoplasm. Under conditions such that cytoplasmic protein synthesis was inhibited by 50% by bis(ethyl)polyamine analogues, mitochondrial protein synthesis was almost completely inhibited. Mitochondrial Ile-tRNA formation was inhibited by bis(ethyl)polyamine analogues at the concentrations that cytoplasmic Ile-tRNA formation was stimulated. This may be one of the reasons for the selective inhibition of mitochondrial protein synthesis. This inhibition was followed by the decrease in ATP content, swelling of mitochondria and depletion of mitochondrial DNA. These results suggest that the early event of metabolic change caused by bis(ethyl)polyamine analogues in cells is the inhibition of protein synthesis, especially of mitochondrial protein synthesis.
OBJECTIVE: To study whether passive smoking at work is a risk factor for coronary heart disease. DESIGN: Case-control study. SETTING: Xi'an, China. SUBJECTS: 59 patients with coronary heart disease and 126 controls, all Chinese women with full time jobs, who had never smoked cigarettes. RESULTS: The crude odds ratio for passive smoking from husband was 2.12 (95% confidence interval 1.06 to 4.25) and at work was 2.45 (1.23 to 4.88). The final logistic regression model, with passive smoking from husband and at work as the base, included age, history of hypertension, type A personality, and total cholesterol and high density lipoprotein cholesterol concentrations; the adjusted odds ratios for passive smoking from husband and at work were 1.24 (0.56 to 2.72) and 1.85 (0.86 to 4.00) respectively. For passive smoking at work, statistically significant linear trends of increasing risks (for both crude and adjusted odds ratios) with increasing exposures (amount exposed daily, number of smokers, number of hours exposed daily, and cumulative exposure) were observed. When these exposure variables were analysed as continuous variables, the crude and adjusted odds ratios were also significant. CONCLUSION: Passive smoking at work is a risk factor for coronary heart disease. Urgent public health measures are needed to reduce smoking and to protect non-smokers from passive smoking in China.
Ten cases of PSP were examined for the presence of neocortical and hippocampal lesions. Samples from 10 cortical areas were stained by Bodian's method and by tau, ubiquitin and beta A4 immunocytochemistry. For the sake of comparison, 5 Alzheimer's cases were studied with the same techniques. Neocortical tangles, star-like tufts of fibers, and neuropil threads were seen in all the cases of PSP. They were stained by Bodian's technique and labelled by an anti-tau, but not by a polyclonal anti-ubiquitin antibody. Senile plaques (Bodian's technique), diffuse or focal amyloid deposits (beta-A4 immunohistochemistry) were rare or absent. The density of tangles was the highest in area 4 and the lowest in area 17. In area 4, the tangles were mainly located in layers V-VI. By contrast, the Alzheimer's tangles had a bimodal distribution (layers III and V-VI). These results favor the specificity of cortical alterations in PSP.
PURPOSE: The presence in some individuals of a prolonged phase of infection with human immunodeficiency virus type 1 (HIV-1) before seroconversion remains controversial. This study was undertaken to determine with a sensitive in vitro amplification technique, the polymerase chain reaction (PCR), whether seronegative individuals with high-risk behaviors could harbor HIV-1 sequences in their peripheral blood mononuclear cells (PBMCs) and remain seronegative for more than 6 months. PATIENTS AND METHODS: Seronegative individuals who engaged in unprotected anogenital intercourse with HIV-1-infected partners or with more than 10 individuals per year, and seronegative individuals who shared needles with seropositive partners, were recruited prospectively over 18 months. HIV-1 DNA and RNA sequences were detected in PBMCs of these individuals with three PCR assays using SK38/SK39, SK145/SK431, and SK68/SK69. Seronegative but PCR-positive patients were also evaluated with p24 antigen capture assay, radioimmunoprecipitation assay, and Western blot. The latter patients were followed prospectively to reproduce PCR-positive results and monitor serologic responses. RESULTS: Sixty-one men and 18 women, with an average age of 34.1 +/- 7.6 years, were recruited: 56 were homosexual men, 18 were heterosexual women, and 5 were heterosexual men. Amplification reactions for HIV-1 of 104 PBMC specimens from 79 patients with negative or indeterminate serologies revealed that 4 patients (5.1%) were positive with PCR for HIV-1 DNA and RNA at the time of enrollment. Positive amplification reactions could not be reproduced in prospective samples for one patient. The analysis of a variable human genomic locus in this patient's PBMCs demonstrated that the first PCR-positive sample and following PCR-negative samples originated from different patients, suggesting a specimen mix-up. Two of the three PCR-positive seronegative patients had symptoms suggestive of acute retroviral disease. Sera from all three patients contained p24 antigen. Two patients seroconverted within 1 month whereas one patient could not be followed prospectively. CONCLUSION: Prolonged infection with HIV-1 without seroconversion was not found in our population of patients at very high risk for HIV-1 infection. All PCR-positive patients seroconverted in less than 1 month.
The growth and development of more than 500 Zea mays seeds flown on LDEF were studied. Somatic mutations, including white-yellow stripes on leaves, dwarfing, change of leaf sheath color or seedling color were observed in plants developed from these seeds. When the frequency of white-yellow formation was used as the endpoint and compared with data from ground based studies, the dose to which maize seeds might be exposed during the flight was estimated to be equivalent to 635 cGy of gamma rays. Seeds from one particular holder gave a high mutation frequency and a wide mutation spectrum. White-yellow stripes on leaves were also found in some of the inbred progenies from plants displayed somatic mutation. Electron microscopy studies showed that the damage of chloroplast development in the white-yellow stripe on leaves was similar between seeds flown on LDEF and that irradiated by accelerated heavy ions on ground.
This study compares the molecular, charge and lectin microheterogeneity of bovine alpha-fetoprotein (bAFP) with human (h) AFP. Molecular weights of bAFP (81 kDa) and hAFP (69 kDa) were detected by Western immunoblotting. Marked crossreactivity was found between bAFP and hAFP by Western immunoblotting but no crossreactivity was noticed by radioimmunoassays. At least seven charge isoforms of bAFP and three isoforms of hAFP were consistently detected by chromatofocusing in a mixture of fetal bovine serum (FBS) and human cord blood (hCB), while only three isoforms of bAFP and hAFP were detected in a mixture of bovine (bAF) and human amniotic fluid (hAF). Using concanavalin A (Con A) chromatography, 50% of bAFP was Con A reactive and 50% non-reactive, while more than 98% of hAFP was Con A reactive in a mixture of FBS and hCB. However, in AFs, 72% of bAFP was Con A reactive, while 89% of hAFP was Con A reactive. These data indicate that marked differences exist in both the charge and lectin microheterogeneity of bovine and human AFP.