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Biomedical subjects

H Hu

Publications and source records attributed to H Hu.

At least 271 records · Page 15Linked to original sources
PubMed1993

Residual cognitive deficits 50 years after lead poisoning during childhood.

The long term neurobehavioural consequences of childhood lead poisoning are not known. In this study adult subjects with a documented history of lead poisoning before age 4 and matched controls were examined with an abbreviated battery of neuropsychological tests including measures of attention, reasoning, memory, motor speed, and current mood. The subjects exposed to lead were inferior to controls on almost all of the cognitive tasks. This pattern of widespread deficits resembles that found in children evaluated at the time of acute exposure to lead rather than the more circumscribed pattern typically seen in adults exposed to lead. Despite having completed as many years of schooling as controls, the subjects exposed to lead were lower in lifetime occupational status. Within the exposed group, performance on the neuropsychological battery and occupational status were related, consistent with the presumed impact of limitations in neuropsychological functioning on everyday life. The results suggest that many subjects exposed to lead suffered acute encephalopathy in childhood which resolved into a chronic subclinical encephalopathy with associated cognitive dysfunction still evident in adulthood. These findings lend support to efforts to limit exposure to lead in childhood.

Cognition Disorders↗
PubMed1993

The left-sided predominance of asbestos-related pleural disease.

In a series of 406 subjects with a diagnosis of asbestos-related pleural disease (ARPD), the left-right symmetry of radiographically diagnosed ARPD was assessed using the International Labour Organization (ILO) system for classifying radiographic abnormalities and three different statistical models for testing the degree of symmetry. The extent of chest disease was found to be greater on the left than on the right for a number of parameters of pleural disease, including the width and extent of localized pleural thickening, the extent of enface pleural thickening, and the extent of diaphragmatic and chest wall calcification. Current cigarette smoking significantly enhanced the observed asymmetry, with the most pronounced effect being in diaphragmatic calcification. Using a composite scale for each subject's pleural disease, the left side had 1.6 times more localized disease than did the right (p < 0.001). Asymmetry in one parameter was associated with asymmetry in another for a number of pairs. The most significant of these associations was between enface pleural thickening and chest wall calcification (Kendall's tau B = 0.42). The pathophysiologic mechanisms that explain these findings remain elusive and need further investigation.

Asbestosis↗
PubMed1993

Antigenic analysis of coxsackievirus B3 with monoclonal antibodies.

All the 16 mouse monoclonal antibodies (McAbs) raised against Nancy strain of coxsackievirus B3, CoxB3(N), were type 3-specific. The reactivity of CoxB3(N) to this McAb panel during the serial passages showed a variation. Three field isolates of CoxB3, all neutralizable with the reference Anti-CoxB3 hyperimmune serum, were checked for the reactivities with the McAb panel. The isolates from the patients in Fujiang reacted with 12 McAbs and variably with the remaining four McAbs. On the basis of the reactivities with different virus strains, the McAbs were found to fall into four groups possibly corresponding to at least four epitopes. A considerable antigenic variation of CoxB3 was thus suggested.

Animals↗
PubMed1993

[Positive identification of the specificity of polymerase chain reaction product].

A method of positive identification of the specificity of polymerase chain reaction (PCR) product using internal oligonucleotide probe is introduced. The hybridization was done on the agarose gel which was dried after electrophoresis. Detection of the expression of T cell receptor a chain variable (TCR V alpha) genes on mRNA level was used as the experimental model. Twenty nine TCR V alpha gene subfamilies could be distinguished clearly in healthy human peripheral blood lymphocytes by this method. Positive identification of PCR product on dried agarose gel by internal oligonucleotide probe is relatively simple and less time consuming.

Base Sequence↗
PubMed1993

[The isolation of Vibrio alginolyticus bacteriophage].

We identified 4 bacteriophages of V. alginolyticus in 29 ones, which were first isolated from seafood. According to their character of the plaques, they were classified into two kinds: one plaque was clear, the other was opaque. The size of these plaques were different and their diameters are 0.5-3.0mm. By electron microscopy observation, they could be classified into two kinds; one has a long axie and hexagemal head, and a thin-long tail, the other has an equal axie hexagenal head and a very short tail, but the edges and corners aren't clear. The multiplication valence of the phages attained to 10(8-9) pfu/ml. Total lysis rate of 4 bacteriophages was 72.22% to V. alginolyticus. However, the lysis rate of single phage was 9.72-44.4%. 4 bacteriophages all had high host specificity. Cross-lysis reaction wasn't found in the test of original solution of bacteriophages to 612 strains of different genus bacteria and 697 strains of genus Vibrio, but they only showed 39% cross-lysis rate to V. parahaemolyticus and most part of this phenomenon disappeared at 10 RTD of the phages. Thus, the obvious relation of consanguinity was showed between two kinds of bacteria strains.

Bacteriophages↗
PubMed1992

Association of serum albumin with blood pressure in the normative aging study.

Little is known regarding serum albumin's epidemiologic relation to chronic disease. The relation of serum albumin to blood pressure was assessed in a longitudinal study of men who have been seen at 3- to 5-year intervals since the early 1960s. The authors analyzed data from over 20 years of observation using cross-sectional multiple regression models of blood pressure that allow for the correlation between repeated measures on the same individual (GLMIC models), longitudinal GLMIC models that incorporate terms for the interaction of time with serum albumin at baseline, and models of the slope of individuals' blood pressure over time. Serum albumin levels were found to have a consistently strong relation with both systolic blood pressure and diastolic blood pressure in the cross-sectional GLMIC models only. This relation did not change appreciably when covariates for age, body mass index, alcohol ingestion, smoking, serum calcium, hematocrit, heart rate, and antihypertensive medications were added. A rise in serum albumin of 1 g/dl was associated with 1.79-mmHg and 0.91-mmHg increases in systolic blood pressure and diastolic blood pressure, respectively. This phenomenon may be related to experimental studies linking tryptophan, the only amino acid to bind noncovalently to serum albumin, to a blood pressure-lowering effect mediated by promotion of 5-hydroxytryptamine synthesis in the brain.

Adult↗
PubMed1992

Simultaneous measurements of the intra- and extra-cellular oxygen concentration in viable cells.

An EPR method that can measure the intra- and extra-cellular oxygen concentration [O2] simultaneously in vitro has been developed using specially designed nitroxides. In the presence of Fe(CN)6(3-) in the medium, intracellular [O2] is measured by a neutral 15N-nitroxide and extracellular [O2] is measured by a negatively charged 14N-nitroxide, since charged species do not enter cells and the EPR spectrum of a 15N-nitroxide does not overlap with that of a 14N-nitroxide. The method is based in part on the minimal broadening of negatively charged nitroxides by Fe(CN)6(3-) and the very effective broadening of neutral nitroxides by the same paramagnetic ions. Results with this method confirm the existence of gradients in [O2] between the extracellular and intracellular compartments in CHO cells and M5076 tumor cells, even without stimulation of cellular respiration by CCCP. The nature of the barrier that needs to be involved to account for the experimental results raises some significant questions.

Animals↗
PubMed1992

Ethanol and oleate inhibition of alpha-ketoisovalerate and 3-hydroxyisobutyrate metabolism by isolated hepatocytes.

Ethanol inhibited glucose synthesis from alpha-ketoisovalerate by isolated rat hepatocytes without significant inhibition of flux through the branched-chain alpha-ketoacid dehydrogenase complex. Accumulation of 3-hydroxyisobutyrate, an intermediate in the catabolism of alpha-ketoisovalerate, was increased by ethanol, indicating inhibition of flux at the level of 3-hydroxyisobutyrate dehydrogenase. 3-Hydroxybutyrate caused the same effects as ethanol, suggesting inhibition was a consequence of an increase in the mitochondrial NADH/NAD+ ratio. Flux through the 3-hydroxyisobutyrate dehydrogenase was more sensitive to regulation by the mitochondrial NADH/NAD+ ratio than flux through the branched-chain alpha-ketoacid dehydrogenase. Oleate also inhibited glucose synthesis from alpha-ketoisovalerate, but marked inhibition of flux through the branched-chain alpha-ketoacid dehydrogenase complex was caused by this substrate.

3-Hydroxybutyric Acid↗
PubMed1992

Antitumor agents. 123. Synthesis and human DNA topoisomerase II inhibitory activity of 2'-chloro derivatives of etoposide and 4 beta-(arylamino)-4'-O-demethylpodophyllotoxins.

The 2'-chloro derivatives of etoposide and 4 beta-(arylamino)-4'-O-demethylpodophyllotoxins have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results showed that none of the compounds are active as a result of the C-2' chloro substitution on ring E. This would suggest that the free rotation of ring E is essential for the aforementioned enzyme inhibitory activity. In addition, these 2'-chloro derivatives showed no significant cytotoxicity (KB).

Antineoplastic Agents↗
PubMed1992

Antitumor agents. 124. New 4 beta-substituted aniline derivatives of 6,7-O,O-demethylene-4'-O-demethylpodophyllotoxin and related compounds as potent inhibitors of human DNA topoisomerase II.

A series of 6,7-O,O-demethylene-4'-O-demethyl-4 beta-(substituted anilino)-4-desoxypodophyllotoxins (18-23), 6,7-O,O-demethylene-6,7-O,O-dimethyl-4'-O-demethyl-4 beta-(substituted anilino)-4-desoxypodophyllotoxins (28-31), and their corresponding 4'-O-methyl analogues (12-17 and 24-27) have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. Compounds 18-23 are 2-fold more potent than etoposide and compounds 12, 16, 17, 30, and 31 are as active as etoposide in their inhibition of the human DNA topoisomerase II. Compounds 19 and 20 and 29-31 are as active or more active than etoposide in causing protein-linked DNA breakage. These results indicate that a free C-4' hydroxy group is essential for the DNA breakage activity, and that the hydroxyl groups at C-6 and -7 positions may be involved in an interaction which is responsible for the inhibitory activity of DNA topoisomerase II. The maintenance of an intact methylene dioxy-type ring-A system would contribute to enhanced activity. In addition, the sterically less hindered substitution at C-6 and C-7 positions may be important for optimal interactions with DNA topoisomerase II. There is no correlation between the ability of these compounds to inhibit DNA topoisomerase II and their ability to cause protein-linked DNA breaks in cells. This may relate to the difference in uptake of these compounds. The better correlation was observed between the protein-linked DNA breaks and the cytotoxicity in KB cells of these compounds.

Aniline Compounds↗
PubMed1992

Immunological tolerance to hapten prevents subsequent induction of hapten-immune pulmonary interstitial fibrosis (HIPIF).

Pulmonary interstitial fibrosis (PIF) is a morphological term which in part can be defined as accumulation of collagen in the extracellular matrix. Previously we showed that hamsters sensitized with 2,4,6-trinitro-1-chlorobenzene (TNCB) developed PIF 14 days after an intratracheal challenge with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The participation of delayed-type hypersensitivity (DTH) in lung collagen deposition was clearly demonstrated. In this paper, we use an adaptation of this model to mice and show that the lung collagen deposition observed was related to the genetic ability of the strain to maintain a DTH response to the immunizing hapten (TNP). Specifically, the lung collagen deposition on Day 14 in hapten-sensitized, challenged animals in high responder to TNP (BALB/c, H-2d) was higher than that in low responder mouse (C57BL/6, H-2b). Furthermore, aged C57BL/6 strain (retired breeders) possessed a DTH response to TNP and produced significantly higher accumulation of hydroxyproline than that of TNBS-challenged-only animals. A DTH mechanism for the induction of the fibrosis is consistent with the observation that responder mice that were made tolerant to the antigen were unable to respond to the lung challenge with a specific increase in lung index or collagen deposition. These results suggest that effector T lymphocytes that are important in DTH play a key role in the regulation of lung collagen deposition in hapten-immune pulmonary interstitial fibrosis (HIPIF) in mice.

Age Factors↗
PubMed1992

Extracorporeal shock wave lithotripsy and methyl tert-butyl ether for gallbladder stones.

Twenty-one patients with gallbladder stones of 1.1-2.6 cm in diameter were treated by extracorporeal shock wave lithotripsy (ESWL) combined with dissolution using methyl tert-butyl ether (MTBE). In 18 of 21 patients, ESWLs were followed by MTBE instillation through a catheter placed percutaneously via the liver and the gallbladder bed under ultrasonographic and fluoroscopic guidance. As a result, 15 of the 18 patients were cleared of their stones after 54 minutes to 3 hours of dissolution. In the other three cases initially treated by MTBE, ESWLs were added because of no dissolution or poor efficacy. Consequently, after additional 3-5 hours of instillation, complete dissolution in one and subtotal dissolution in two were achieved. Our preliminary results indicated that ESWL followed by MTBE dissolution in the management of cholesterol gallbladder stones was reasonable. On the one hand, ESWL can enhance dissolution by increasing the surface area of stone, and on the other hand MTBE can instantly clear the fragments created by ESWL, so that long-term bile acid intake and potential side effects caused by fragment migration might be avoided.

Adult↗
PubMed1992

Delayed-type hypersensitivity responses regulate collagen deposition in the lung.

A previous report showed that hamsters immunized by epicutaneous application of 2,4,6-trinitrochloro-1-benzene (TNCB) were susceptible to the development of pulmonary interstitial fibrosis (PIF) if challenged in the lung with the water-soluble form of this hapten 2,4,6-trinitrobenzene sulphonic acid (TNBS). In this study, we investigated the immunological mechanisms that contributed to increased collagen content in the lungs of hapten-immune hamsters after receiving a pulmonary challenge of the sensitizing hapten trinitrophenol (TNP). In order to evaluate the concept that delayed-type hypersensitivity (DTH) reaction modulated their response to TNP in the lung such that it eventuated into PIF, we compared the cutaneous DTH response (48 hr after challenge) with lung collagen deposition (14 days after challenge) in several lines (strains) of hamsters. The inbred LSH strain, was a high responder in the DTH assay to TNP and developed non-resolving PIF in the hapten-immune animals. This is called hapten-immune pulmonary interstitial fibrosis or HIPIF. We also observed that female LSH hamsters were more susceptible to HIPIF induced by TNP than males. On the other hand, age factors influenced DTH and PIF in random-bred LVG hamsters since young hamsters (3 months old) were low responders to TNP and did not develop PIF in the HIPIF model but matured LVG hamsters (retired breeders) possessed DTH reactivity to TNP and subsequently developed PIF. These results suggest that lung collagen deposition in hapten-immune hamster is regulated by T-lymphocyte-mediated immune inflammation (DTH) in the lung and both are dependent on the ability to develop a cutaneous DTH reaction to the hapten. The elucidation of possible mechanisms of DTH-mediated non-granulomatous, non-resolving PIF is important for understanding of the role of environmental chemicals similar in action to haptens in the mediation of skin and lung diseases.

Aging↗
PubMed1991

EPR method for the measurement of cellular sulfhydryl groups.

An EPR method that can measure the concentration of sulfhydryl groups in intact cells has been developed using a specially designed stable nitroxyl biradical. The biradical, RS-SR, contains a disulfide bond and readily undergoes thiol-disulfide exchange reactions with thiols resulting in a characteristic EPR spectrum which can be analyzed to provide a quantitative measure of sulfhydryl groups. The data obtained from the EPR method are in good agreement with those obtained from the conventional optical method using Ellman's reagent. The advantages of the EPR method are that the measurement can be carried out on intact cells or any other highly colored, absorbing and/or scattering solutions and the sensitivity is such that only a few cells (approximately 100) are needed for each quantitative measurement.

Animals↗