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H M Ren

Publications and source records attributed to H M Ren.

9 recordsLinked to original sources
PubMed2006

Assessment of soil lead exposure in children in Shenyang, China.

Soil lead pollution is serious in Shenyang, China. The paper brings together the soil work, the bioaccessibility, and the blood lead data to assess the soil lead exposure in children in Shenyang, China. Approximately 15.25% of the samples were above China Environment Protection Agency guideline concentration for soil Pb to protect human from health risk (350 mgkg(-1)). Pb concentrations varied among use scenarios. The main lead contamination sources are industry emission and automobile exhaust. Bioaccessibility also varied among use scenarios. Children, who ingested soil from industrial area, public parks, kindergarten playground, and commercial area, are more susceptible to soil lead toxicity. The industrial area soil samples presented higher bioaccessibility compared to the other use scenario soil samples contaminated by automobile exhaust. The result also suggested a most significant linear relationship between the level of Pb contamination and the amount of Pb mobilized from soil into ingestion juice. Soil pH seemed to have insignificant influence on bioaccessibility in the present study. Bioaccessibility was mainly controlled by other factors that are not investigated in this study. A linear relationship between children blood lead and soil intestinal bioaccessibility was present in the study. Children who are 4-5 years old are more likely to demonstrate the significant relationship between soil lead bioaccessibility and blood lead as their behaviors place them at greatest risk of soil lead toxicity, and their blood lead levels are more likely to represent recent exposure.

Age Factors↗
PubMed2001

[Identification of the existence of luteinizing hormone in pituitary vacuoles of rats].

It is generally believed that glycoprotein hormone exists in granules of the gonadotrophin (GTH) cells, and recent studies on the formation and secretion of glycoprotein hormones also concern much on the changes in the pituitary granules. In our previous studies, it was found that the secretion of luteinizing hormone (LH) was closely related to the morphological changes in pituitary vacuoles of rats, and the morphology of GTH cells was also closely related to the changes in vacuolar morphology. Therefore, it appears that there exists an inseparable relationship between the storage and secretion of LH and pituitary vacuoles. In order to examine whether the pituitary vacuoles contain LH in rats, and to further explore if LH is stored and released by the pituitary vacuoles, the vacuoles were separated and purified from pituitary, cortex and liver tissues by density gradient centrifugation. The vacuolar protein components, LH and glycoproteins were determined by the methods of SDS-PAGE, Western immunoblot and Con A/HRP, respectively. The results showed that (1) abundant protein components with various molecular masses were present in the vacuoles of the pituitary, cortex and liver in male, female and ovariectomized rats, and some of the protein components were similar in the molecular mass; (2) both pituitary tissues and vacuoles contained LH, and their LH levels had no significant difference by quantitative analysis of extracted protein samples; and (3) glycoproteins of various molecular masses were found in the vacuoles of the pituitary, cortex and liver, but the same position of stained glycoprotein band and LH molecular mass was only observed in the pituitary vacuoles. From the results given above, it can be concluded that LH specifically exists in the pituitary vacuoles, although there are some similar protein components in various cellular vacuoles. The possibility was further demonstrated at the molecular level that the pituitary vacuoles may have the function of storing and releasing LH due to the pituitary vacuoles containing LH with assembled glycone.

Animals↗
PubMed2000

[Human DNA polymorphism of HaeIII system in Chinese oriental, Han population].

DNA typing by restriction fragment length polymorphism (RFLP) analysis was an extremely important technique used in forensic science identification, paternity test and gene diagnosis. While RFLP testing was a highly informative method, it traditionally had several disadvantages. It was time consuming and involved in working with radioactive phosphorus. A chemiluminescent detection of RFLP technique that was faster and safer than isotopic detection. The chemiluminescent system had a good sensitivity of detecting 3-25 ng sample DNA. The development of direct alkaline phosphatase (AP) conjugated probes and improved chemiluminescent substrates provided a non-isotopic detection method that equaled or surpassed 32P detection systems. Population genetic studies were performed using direct alkaline phosphatase (AP) conjugated oligonucleotide probes (AL1874, YNH24, TBQ7, VI) that recognized four hypervariable number of tandem repeats regions (D2S92, D2S44, D10S28, D17S79 loci) respectively in the human genome. DNA from approximately 480 unrelated individuals, subdivided into oriental group were digested with HaeIII enzyme and were successively hybridized to each DNA probe. The number of distinct DNA fragments identified for each of these regions varies from 37 to more than 78. An allele frequency distribution was determined for each locus with the computer and digitizer. The results showed significant differences between different races (American-blacks, Caucasians, and Orientals), in the pattern of distributions as well as in the relative frequency of the most common alleles of D2S92, D2S44, D10S28, and D17S79. The results showed that the analysis of these loci had useful applications in genetics and in forensic identity.

Alleles↗
PubMed1999

[HLA-DRB alleles polymorphism in Han, Hui, Uygur and Tibetan populations in northwestern China].

According to the 11th THW standard, we designed a pair of primers by which a segment of 256bp of HLA-DRB1, B3, B4, and B5 could be amplified simultaneously. Twenty-seven oligonucleotide probes were designed and synthesized for 39 loci on DRB1, 3 on DRB3, 1 on DRB4 and 3 on DRB5. A PCR-SSO DNA typing protocol was built, which met the standard of HLA class II DNA typing in 11th IHW. With this method, 186 of Chinese (Han) in Xi'an, 169 of Hui in Ningxia, 200 of Uygur in Xinjiang, and 188 of Tibetan in Tibet were detected with a comparison study. The genetic distribution of 46 loci of DRB in four ethnic healthy populations were surveyed. No diversity has been found between Han and Hui in DRB. DRB1 * 02(16.9%), DRB1 * 07 (13.1%), and DRB1 * 09(12.0%) were the higher frequent loci in Han. More DRB loci were detected in Tibetan but without higher loci as in Han and Hui. The DRB polymorphism of Uygur population was similar to Caucasian. A discriminative highest frequency of DRB1 * 07(23.8%) was found in Uygur, which implied a selection happened.

Alleles↗
PubMed1997

Photoinactivation of the F1-ATPase from spinach chloroplasts by dequalinium is accompanied by derivatization of methionine beta183.

In contrast to the F1-ATPases from bovine mitochondria and the thermophilic Bacillus PS3, which are reversibly inhibited by dequalinium in the absence of irradiation, the Mg2+-ATPase activity of heat- or dithiothreitol-activated chloroplast F1 (CF1) from spinach chloroplasts is slightly stimulated by dequalinium. Conversely, dequalinium is a partial inhibitor (maximal inhibition is 85-90%) of the Ca2+-ATPase of CF1 activated by heat, dithiothreitol, or octylglucoside. The Mg2+- and Ca2+-ATPase activities of CF1 respond differently in the presence of lauryl dimethylamine oxide (LDAO) in the assay medium. Whereas the Mg2+-ATPase activity of heat- or dithiothreitol-activated CF1 is stimulated up to 14-fold by increasing concentrations of LDAO, the Ca2+-ATPase is inhibited in a biphasic manner by increasing concentrations of LDAO. In the presence of LDAO, dequalinium does not stimulate the heat-activated Mg2+-ATPase over that promoted by LDAO alone. That dequalinium slightly stimulates Mg2+-ATPase activity although it inhibits Ca2+-ATPase activity can be reconciled by assuming that dequalinium binds to two sites in CF1, a stimulatory site that also binds LDAO and an inhibitory site. By acting as a partial inhibitor of the Mg2+-ATPase activity that it activates, the combined effect of dequalinium is modest stimulation. Irradiation of heat- or dithiothreitol-activated CF1 or the alpha3beta3gamma subcomplex of CF1 in the presence of 12 microM dequalinium led to rapid photoinactivation. ATP and ADP, separately or in combination with Mg2+, protect against photoinactivation. After photoinactivating the alpha3beta3gamma subcomplex of CF1 with [14C]dequalinium, tryptic and peptic digests of the isolated, derivatized beta subunit were fractionated by high performance liquid chromatography. Sequencing of the isolated, radioactive tryptic and peptic peptides revealed that Metbeta183, which is at or near the catalytic site, is derivatized in a single beta subunit when CF1 is photoinactivated with [14C]dequalinium.

Ca(2+) Mg(2+)-ATPase↗
PubMed1994

Cardiac responses activated by nicotine in canine ganglial plexus between aorta and pulmonary artery.

In order to study the location and function of nicotine-sensitive neurons of cardiac ganglial plexuses, microdissections of collections of fat pads were carried out, and nicotine (100 micrograms) was injected into the ganglial plexus between aorta and pulmonary artery (A-PGP) in 30 anesthetized open-chest dogs. There were numerous ganglia or neurons in A-PGP. Either positive or negative inotropic and chronotropic responses were elicited following injections of nicotine into A-PGP. Control injections of 0.1 ml saline into A-PGP and injections of nicotine (100 or 200 micrograms) into right marginal ganglial plexus did not elicit any cardiac responses. After acute decentralization, nicotine (100 micrograms) was again injected into the same locus of A-PGP. Some positive and negative responses could still be induced, but their frequencies were reduced. These suggest that nicotine can directly activate the efferent parasympathetic and sympathetic neurons and indirectly activate them by stimulating the afferent neurons existing on the surface of dog heart.

Animals↗
PubMed1992

[Effects of castration and testosterone-replacement on hypothalamic and plasma luteinizing hormone-releasing hormone levels in the aged male rat].

Hypothalamic and plasma luteinizing hormone-releasing hormone (LHRH) levels following orchidectomy (ORDX) and testosterone (T)-replacement were compared between young (2-3 months old) and aged (24-26 months old) male rats by radioimmunoassay. Plasma T level and hypothalamic LHRH content are markedly decreased in the aged rat as compared to those of the young rat, whereas plasma LHRH levels are similar in the two groups. Following ORDX and ORDX plus T-replacement, plasma T levels in both groups are about the same, whereas the rates of variation of hypothalamic and plasma LHRH levels in the aged rat are significantly lower than those in the young rat. These results suggest that the negative feedback mechanism of the hypothalamic LHRHergic system is impaired in the aged rat, which may be one of the important reasons causing age-dependent deterioration of the functional control of hypothalamic-pituitary-testicular axis.

Aging↗