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Biomedical subjects

Z Yin

Publications and source records attributed to Z Yin.

122 records · Page 7Linked to original sources
PubMed1992

[Synthesis of O,O'-dialkyl-O''-(5-substituted-3-benzothienglyoxylonitrile oximino) phosphates and thiophosphates].

In order to search for potential molluscicidal synergists, eighteen O,O'-dialkyl-O''-(5-substituted-3-benzothienglyoxylonitrile oximino) phosphates and thiophosphates were synthesized. Preliminary biological screening showed that compounds I2,3,7,11,12 combined with sodium pentachlorophenate exhibited significant molluscicidal synergism against snails (Oncomelanis hupensis).

Animals↗
PubMed1992

The suspension culture of Tripterygium wilfordii.

In suspension culturing of Tripterygium wilfordii, 18.4 mg/l of dry cells and 9.184 mg/l of diterpene-lactone compounds were obtained from 6,7-V liquid medium containing 1 mg/l NAA. Besides those within the cells, diterpene-lactone compounds were also found in the cultured liquid and the yield reached 30.16-43.14% of the total yield. The total yield of diterpene-lactone compounds in suspension culture (6,7-V medium containing 1 mg/l NAA) was 12.19 times as much as that in the roots of the original plant. In addition, 3 samples of diterpene-lactone extracts from the suspension culture were found toxic to KB cells. Compared with those in solid culture, less incubation time was needed and more diterpene-lactone compounds were produced in suspension culture.

Cell Line↗
PubMed1991

Degradation of intracellular endogenous proteins following serum deprivation in mammalian cell cultures: theoretical considerations of the role of very-fast turnover proteins in growth regulation.

This paper discusses the way in which serum deprivation affects the turnover of nascent or newly synthesised proteins in mammalian cells. A theoretical treatment of their turnover relative to changes in rate of protein synthesis and the turnover of existing or "resident" proteins is presented. Previous experimental work has not seriously addressed this question because the pulses of radiolabelling of proteins have been too long to identify the very-fast turnover population (Wheatley et al., 1980; Bohley, 1987). Logically one would expect cell growth rate to be regulated by the rate at which new proteins become incorporated into the cell within the first 30 min of their existence. This requires their successful integration at what we will refer to as the "growing point", recognizing that at any time there may be thousands of such sites. Growth is a simple term betraying the complexity of the processes involved--synthesis, processing, sorting, targeting, and stabilization of macromolecules, and their successful integration into functional assemblies at appropriate locations. Turnover of the truly short-lived, very-fast turnover proteins at the "growing point" is affected by serum adjustment, but it is not the only change since synthetic rate quickly responds, as also does the turnover rate of long-lived proteins. Our theoretical discussion will relate to recent findings in 3T3 and HeLa cell cultures after serum modulation, lines with quite different dependencies on serum growth factors.

3T3 Cells↗
PubMed1990

[Preparation and cytotoxicity of McAb-HSA-MTX conjugates].

In the present study, methotrexate (MTX), was conjugated with a murine monoclonal antibody (79) to human common acute lymphoblastic leukemia antigen (CALLA), with human serum albumin (HSA) as an intermediary. The highest molar ratio of McAb 79:HSA:MTX in the conjugates was 1:2. 63:117. The conjugates obtained retained both antibody binding and drug activities. Although there was some loss of drug activity in binding to antibody, the toxicity of McAb79-HSA-MTX was entirely specific for the target cell, and the cytotoxicity of McAb79-HSA-MTX against CALLA+ cells was greater than that of control S13 (Anti-human urokinase)-HSA-MTX. The ratio of 79-HSA-MTX cytotoxicity to the target and non-target cells was 66:1, whereas there was no cytotoxicity to target cells when McAb79 was used only. There was no cytotoxic difference between 79-HSA-MTX and S13-HSA-MTX against CALLA- SB cells. These results suggest that the cytotoxicity of 79-HSA-MTX against CALLA leukemia cells is specific and this specificity is mediated by McAb79.

Albumins↗
PubMed1990

[Effect of ke-tang-Ling administration on the function of pancreatic islets cells in non-insulin-dependent diabetes mellitus].

Radioimmunoassay methods were modified for insulin(IRI), C-peptide (IRCP) and glucagon (IRG) in the clinical investigation on normal subjects and 38 patients with non-insulin-dependent diabetes mellitus (NIDDM). In the control group, the peaks of glucose and IRI appeared 1 hour after glucose was taken. IRCP peak, however, appeared 1 hour later. IRG showed its maximum value on fasting and then reached its lowest point at the second hour after glucose loading. The authors' interests were focused on the changes of blood glucose, IRI, IRCP, and IRG in oral glucose tolerance test (OGTT) before and after Ke-Tang-Ling (KTL) was administered in NIDDM. The results demonstrate that the glucose levels and undercure areas at various phases in OGTT were significantly decreased (P less than 0.01) in comparison of before and after the treatment with KTL in NIDDM (including obese and non-obese groups). In non-obese group, however, IRI, IRCP, and their undercure were remarkably increased (P less than 0.01). In obese group their values were decreased. It suggests that KTL plays a therapeutic role in decreasing blood glucose in non-obese NIDDM. The mechanism involved in this process may be related to its stimulating effect. IRG levels were decreased also (P less than 0.01) after the treatment with KTL in both obese and non-obese NIDDM, suggesting an inhibitory effect on glucagon secretion from alpha cells in pancrease.

Adult↗
PubMed1984

Induction by butylated hydroxyanisole of specific molecular forms of glutathione S-transferase and UDP-glucuronyltransferase and inhibition of development of gamma-glutamyl transpeptidase-positive foci in rat liver.

Effects of an antioxidant, butylated (3-tert-butyl-4-) hydroxyanisole (BHA) on the induction of specific molecular forms of glutathione S-transferase (GST), UDP-glucuronyltransferase (UDP-GT) and other glutathione-related enzymes in rat liver were investigated. The development of gamma-glutamyl transpeptidase (gamma-GTP)-positive foci and hyperplastic nodules induced by diethylnitrosamine, 200 mg/kg i.p., followed by 0.02% N-2-fluorenylacetamide (FAA) in diet plus partial hepatectomy was inhibited by the administration of 0.75% BHA in the FAA-containing diet. Inhibition was reflected in decreased area of gamma-GTP-positive foci which correlated with a decrease in gamma-GTP activity measured biochemically. Under the present experimental conditions, total activities of GSTs, especially that of GST-A form, and of UDP-GTs, especially that of the late fetal form (o-GT), were markedly increased, together with glutathione levels in the whole liver, within one week after BHA administration. Without BHA administration the activities of GST-A and o-GT, as well as glutathione levels, were also increased by FAA treatment, primarily localized within gamma-GTP-positive foci. These results suggest that the induction of specific molecular forms of detoxicating enzymes either in enzyme-altered foci or in the whole liver may play an important role in determining the extent of development of preneoplastic nodules from initiated foci under the short term induction conditions used.

Animals↗
PubMed1983

Molecular forms of glutathione S-transferase and UDP-glucuronyltransferase as hepatic preneoplastic marker enzymes.

Changes in molecular forms of glutathione S-transferase (GST) and UDP-glucuronyltransferase (UDP-GT) as hepatic detoxicating enzymes were investigated during chemical hepatocarcinogenesis in the rat. The activity and the protein amount (formula; see text) itself of the GST-A form, which has fetal characteristics and is separable from other forms by CM-Sephadex column chromatography and by immunologic techniques, was much increased in gamma-glutamyl transpeptidase (gamma-GTP)-positive foci or hyperplastic nodules (HNs) induced by diethylnitrosamine and 2-fluorenylacetamide or 3'-methyl-4-dimethylaminoazobenzene. The activity of enzyme 1 (late fetal form) of UDP-GT assayed with o-aminophenol (o-GT) also increased with increased number of the foci or HNs, while the activity of enzyme 2 (neonatal form) assayed with phenolphthalein (p-GT) changed but little. The foci and HNs were stained more strongly than the nonnodular areas immunohistochemically using the antibody against purified GST-A or o-GT. The two activities were also increased in well-differentiated hepatomas, but they were decreased in moderately and poorly differentiated hepatomas, and activating enzymes such as cytochrome P-450 were markedly decreased from HN. GST-A and o-GT differ from fetal enzymes such as those of carbohydrate metabolism in that they are inducible in the short-term by drugs, including carcinogens, and they show the highest activities in HNs, and so they may be considered as hepatic preneoplastic (PN) antigens.

Animals↗
PubMed1982

Changes in activities of uridine diphosphate-glucuronyltransferases during chemical hepatocarcinogenesis.

Changes in the activities of hepatic uridine diphosphate-glucuronyltransferases (UDP-GTs) were investigated during the induction of hyperplastic nodules (enzyme-altered foci) by a system consisting of diethylnitrosamine (DEN) followed by N-2-fluoroenylacetamide (FAA) and including partial hepatectomy. The activity of the late fetal form of UDP-GT, which was assayed towards o-aminophenol (o-GT activity), was induced rapidly by a single ip injection of DEN (200 mg/kg) or 3-methylcholanthrene (40 mg/kg) or by the continuous administration of FAA (0.02% in diet) alone. This activity further increased with the appearance of the nodules, while the activity of the neonatal form, which was assayed toward phenolphthalein (p-GT activity) and was inducible by phenobarbital, increased only slightly. The increased o-GT activity showed a good correlation with the increased number or area of enzyme-altered foci detected by gamma-glutamyltransferase activity staining, but the p-GT activity did not, though it was significantly increased. In hyperplastic nodules and well differentiated hepatomas induced by DEN (0.1% in drinking water, 3 weeks) but isolated long after cessation of DEN, o-GT activity was markedly increased, but p-GT activity was decreased or remained at the level of normal rat liver. These data indicate that the increased o-GT activity may be one of the enzyme markers for preneoplastic hepatic cells. An antioxidant, butylated hydroxyanisole (BHA) (0.75% in diet), markedly elevated the hepatic o-GT activity rapidly after being administered with FAA in the above system, and the induction of the nodules was inhibited.

2-Acetylaminofluorene↗
PubMedDate not supplied

An ab initio algorithm for low-resolution 3-D reconstructions from cryoelectron microscopy images.

A statistical method for determining low-resolution 3-D reconstructions of virus particles from cryoelectron microscope images by an ab initio algorithm is described. The method begins with a novel linear reconstruction method that generates a spherically symmetric reconstruction, which is followed by a nonlinear reconstruction method implementing an expectation-maximization procedure using the spherically symmetric reconstruction as an initial condition and resulting in a reconstruction with icosahedral symmetry. An important characteristic of the complete method is that very little need be known about the particle before the reconstruction is computed, in particular, only the type of symmetry and inner and outer radii. The method is demonstrated on synthetic cowpea mosaic virus data, and its robustness to 5% errors in the contrast transfer function, 5% errors in the location of the center of the particles in the images, and 5% distortion in the 3-D structure from which the images are derived is demonstrated numerically.

Algorithms↗
PubMedDate not supplied

Illegal drug use, alcohol and aggressive crime among Mexican-American and white male arrestees in San Antonio.

This research explores the relationship between use of certain drugs and aggressive crimes among Mexican-American and White male arrestees in San Antonio, Texas, for 1992. This is based on a Drug Use Forecasting (DUF) sample of 534 male arrestees administered a drug urine analysis test and questionnaire by the Department of Justice and the city of San Antonio. Using a four-way asymmetrical analysis, logit-models were tested to examine the relationships between the response variable, the types of crimes charged (nonaggressive versus aggressive) and a set of exploratory variables, ethnicity (White versus Hispanic), drug test results (positive versus negative), and alcohol use (infrequent versus frequent). The logit-analysis allows the specification of a subset of relevant models to be tested for their adequacy of fit. Findings indicate a complex but interpretable pattern between drug use, alcohol use patterns, and aggressive crimes. A surprising finding was that more aggressive crimes were committed by all men testing negative for drugs. Mexican-Americans with frequent alcohol use and testing positive for drugs were twice as likely to commit an aggressive crime (a crime associated with violence) than Whites in the same subgroup. The implication of these findings for prevention strategies aimed at alcohol and other drug users involved in violent behavior is discussed.

Adult↗