Biomedical subjects

B Huang

Publications and source records attributed to B Huang.

At least 163 records · Page 9Linked to original sources

PubMed1995

Erectile response to topical, intraurethral and intracorporal pharmacotherapy in a rat model of spinal cord injury.

In order to compare the erectile response to topical, intraurethral and intracorporal administration of vasoactive substances in neurologically intact and spinal cord injured (SCI) rats, a standard rat model of SCI using impact trauma at the level of T10 was employed, comparing the tumescence of 24 SCI and 25 control rats. Four weeks after SCI, the effect of vasoactive substances on erectile function was evaluated. Under ketamine anesthesia, the penis was exposed and intracorporal pressure (ICP) was monitored using saline infusion cavernosometry through a 24-gauge catheter inserted into one corpus cavernosum. Changes in ICP were recorded in response to the topical and intraurethral (IU) application of minoxidil (0.1 ml, 2% solution) and 2% nitroglycerin (NTG) ointment (0.1 gm), as well as the intracorporal (IC) administration of papaverine (0.0001-0.10 mg/kg). Results indicated that the mean baseline ICP was 8 +/- 5 mmHg for SCI and 9 +/- 4 mmHg for control rats. No response to topical therapy onto the undegloved penis was noted in either SCI or control rats. IU application of minoxidil to the degloved phallus developed ICP greater than that achieved with topical minoxidil; the topical application of NTG was less effective. In SCI rats, IC papaverine injection achieved an ICP of 56.9 +/- 24.3 mmHg, whereas papaverine in control rats generated an ICP of 43.5 +/- 38.8 mmHg. A greater increase in ICP at lower doses of each agent occurred in SCI than in control rats. We conclude that only the degloved phallus responded to topical vasoactive pharmacotherapy. Although both topical and IU applications of NTG and minoxidil increase ICP, tumescence was significantly less than that achieved with IC injection of papaverine. The IU application of minoxidil demonstrated significantly greater activity than other topical therapies. SCI rats displayed a supersensitive response to all modes of pharmacologic erectile therapy.

Administration, Topical↗

PubMed1995

Molecular cloning and expression of human granulocyte-macrophage colony stimulating factor in Escherichia coli system.

Human granulocyte-macrophage stimulating factor (hGM-CSF) is an important hematopoietic growth factor. hGM-CSF is able to stimulate hematopoietic progenitors to produce granulocytes, macrophages and eosinophils. hGM-CSF also shows the potential to treat myeloid leukemias. In order to prepare enough hGM-CSF, a genetically engineered strain E. coli HB101/pZW.GM47 was constructed by DNA recombination technologies in the present study, and characterized by restriction analysis, DNA sequencing, SDS-PAGE, Western blotting and bioassays. The strain has been shown to produce a 14kDa mature hGM-CSF protein with expression level higher than 40% and a specific activity of 5.0 x 10(7) u/mg which shows a good potential for clinical applications.

Bacterial Proteins↗

PubMed1995

Molecular characterization of two proximal deletion breakpoint regions in both Prader-Willi and Angelman syndrome patients.

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct mental retardation syndromes caused by paternal and maternal deficiencies, respectively, in chromosome 15q11-q13. Approximately 70% of these patients have a large deletion of approximately 4 Mb extending from D15S9 (ML34) through D15S12 (IR10). To further characterize the deletion breakpoints proximal to D15S9, three new polymorphic microsatellite markers were developed that showed observed heterozygosities of 60%-87%. D15S541 and D15S542 were isolated from YAC A124A3 containing the D15S18 (IR39) locus. D15S543 was isolated from a cosmid cloned from the proximal right end of YAC 254B5 containing the D15S9 (ML34) locus. Gene-centromere mapping of these markers, using a panel of ovarian teratomas of known meiotic origin, extended the genetic map of chromosome 15 by 2-3 cM toward the centromere. Analysis of the more proximal S541/S542 markers on 53 Prader-Willi and 33 Angelman deletion patients indicated two classes of patients: 44% (35/80) of the informative patients were deleted for these markers (class I), while 56% (45/80) were not deleted (class II), with no difference between PWS and AS. In contrast, D15S543 was deleted in all informative patients (13/48) or showed the presence of a single allele (in 35/48 patients), suggesting that this marker is deleted in the majority of PWS and AS cases. These results confirm the presence of two common proximal deletion breakpoint regions in both Prader-Willi and Angelman syndromes and are consistent with the same deletion mechanism being responsible for paternal and maternal deletions. One breakpoint region lies between D15S541/S542 and D15S543, with an additional breakpoint region being proximal to D15S541/S542.

Angelman Syndrome↗

PubMed1995

Arachidonic acid as a possible negative feedback inhibitor of nicotinic acetylcholine receptors on neurons.

Neuronal acetylcholine receptors, being highly permeable to calcium, are likely to regulate calcium-dependent events in neurons. Arachidonic acid is a membrane-permeant second messenger that can be released from membrane phospholipids by phospholipases in a calcium-dependent manner. We show here that activation of neuronal acetylcholine receptors triggers release of 3H-arachidonic acid in a calcium-dependent manner from neurons preloaded with the fatty acid. Moreover, low concentrations of arachidonic acid reversibly inhibit the receptors and act most efficiently on receptors likely to have the highest permeability to calcium, namely receptors containing alpha 7 subunits. Low concentrations of arachidonic acid also reversibly inhibit alpha 7-containing receptors expressed in Xenopus oocytes following injection of alpha 7 cRNA. The oocyte results indicate following injection of alpha 7 cRNA. The oocyte results indicate that the inhibition is a feature of the receptors rather than a consequence of neuron-specific machinery. The inhibition is not mediated by specific metabolites of arachidonic acid because the effects can be mimicked by other fatty acids; their effectiveness correlates with their content of double bonds. In contrast to arachidonic effects on calcium currents, inhibition of neuronal nicotinic receptors by the fatty acid cannot be prevented by blocking production of free radicals or by inhibiting protein kinase C. An alternative mechanism is that arachidonic acid binds directly to the receptors or perturbs the local environment in such a manner as to constrain receptor function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

[Interleukin-2 gene cloning and expression in S. cerevisiae].

Mature human Interleukin-2 gene was amplified from IL-2 cDNA by PCR methods. The PCR product was cloned into pUC12 plasmid at Sma I site, then precisely engineered into an intermidiate vector pSK43SB which were digested with Hind III, mung bean nuclease, and Sal I. Added BamH I linker to Cla I site of pSK43SB-IL2 to produce one more BamH I site, then digested pSK43DB-IL2 with restriction enzyme BamH I, the BamH I fragment with an alpha-factor leading sequence, IL2 gene and cycl terminater were produced. It was then cloned into a typical high efficiency episomal expression vector YEpHc8. Human IL-2 protein was purified from supernatant secreted by yeast transformants of YEpHc8-IL2 leading by alpha-factor promoter with IL-2 right translational reading frame and accurate cleavage site. High level expression of IL-2 with highly activity has been purified. A sugar specific silver staining method and 3H sugar labelling experiment has shown the detection of carbohydrate component.

Cloning, Molecular↗

PubMed1995

[Changes of lung function in ex-smokers].

Lung function in 31 ex-smokers, 17 with six to eight and 14 with 11 to 15 years of cigarette smoking, and pair-matched controls were studied. Results showed smoking could cause prolongation of mean through time and partial mean through time in forced expiratory volume scheme, which increased with length of smoking, and multiple abnormal in lung function tests. Lung function could improve apparently after the cease of smoking. It suggested quitting of smoking could prevent lung function from further damage, or reverse the damaged lung function.

Adult↗

PubMed1995

[Effects of hypoxia on the phenotype of porcine pulmonary arterial smooth muscle cells in vitro].

The effects of hypoxia on phenotype modulation of pulmonary artery smooth muscle cells (PASMC) was observed using cell culture and morphometry analysis. The results showed that the number of diploid cells and alpha-sm-actin of the hypoxic endothelial cell condition medium group (HECCM) was lower and the myofibrils were even less than that of the normal endothelial cell condition medium group (NECCM). On the contrary, the volume density of rough endothelial reticulum (RER) and mitochondria of the HECCM group were higher than that of the NECCM group. However, under hypoxic condition for 24 hours, the phenotype of cultured PASMCs remained unchanged. It suggests that the HECCM can induce phenotype modulation of PASMCs, may be mediated by the pulmonary artery endothelial cells (PAECs) which can secrete some cytokines affecting the PASMCs.

Animals↗

PubMed1994

A small, high-copy-number vector suitable for both in vitro and in vivo gene expression.

A 2433-bp, high-copy-number expression vector, pUK, was constructed from pUC19 and pKK223-3. The genes encoding chicken adenylate kinase (AK) and phospholipase A2, cloned into pUK, were highly expressed in vitro using the coupled transcription/translation system of Zubay. High-level in vivo expression in Escherichia coli was also demonstrated for the AK gene cloned in this vector. The multiple cloning site (MCS) of pKK223-3 was preserved in pUK. In addition, three more sites in the MCS sequence, AccI, BamHI and SalI, were made unique for the convenience of cloning.

Adenylate Kinase↗

PubMed1994

Mental retardation and Ullrich-Turner syndrome in cases with 45,X/46X,+mar: additional support for the loss of the X-inactivation center hypothesis.

Four cases having mosaicism for a small marker or ring [45,X/46,X,+mar or 45,X/46,X,+r] chromosome were ascertained following cytogenetic studies requested because of minor anomalies (cases 1, 3, and 4) and/or short stature (cases 2 and 4). While all 4 cases had traits typical of Ullrich-Turner syndrome (UTS), cases 1, 3, and 4 had manifestations not usually present in UTS, including unusual facial appearance, mental retardation/developmental delay (MR/DD) (cases 3 and 4), and syndactylies (case 1). The facial appearances of cases 1 and 3 were similar yet distinct from that of case 4. Using fluorescence in situ hybridization (FISH), each of the markers in these 4 cases was identified as having been derived from an X chromosome. The level of mosaicism for the mar/r(X) cell line in these cases varied from 70% (case 1) to 16% (case 4) but was not apparently correlated with the presence of MR/DD. Replication studies demonstrated a probable early replication pattern for the mar/r(X) in cases 1, 3, and 4, while the marker in case 2 was apparently late replicating. To date, 41 individuals having mosaicism for a small mar/r(X) chromosome have been described. Interestingly, most of the 14 individuals having a presumedly active mar/r(X) demonstrated clinical findings atypical of UTS, including abnormal facial changes (11) and MR/DD (13). MR was noted most frequently in those cases having at least 50% mosaicism for the marker or ring. In contrast, atypical UTS facial appearance or MR/DD was not noted in 14 of the 16 cases with UTS who carried a probable late replicating marker or ring. In conclusion, although the phenotype of 45,X/46,X,mar/r(X) individuals appears to be influenced by the genetic content and degree of mosaicism for the mar/r(X), the most significant factor associated with MR/DD appears to be the activity status of the mar/r(X) chromosome. Thus, our 4 cases provide further support for the hypothesis that a lack of inactivation of a small mar/r(X) chromosome may be a factor leading to the MR and other phenotypic abnormalities seen in this subset of individuals having atypical UTS.

Child↗

PubMed1994

High level expression in Escherichia coli and characterization of the EF-hand calcium-binding protein caltractin.

Caltractin is a member of the calmodulin superfamily of Ca(2+)-binding proteins that was originally cloned at the DNA level from the unicellular green alga Chlamydomonas reinhardtii. Human and mouse homologs to algal caltractin have been recently characterized. In the studies reported here, recombinant Chlamydomonas caltractin was expressed at high levels in Escherichia coli and purified to homogeneity. The use of the ompT-host BL21 proved critical for obtaining high yields of homogeneous full-length protein. Growth and purification protocols were optimized to allow reproducible and efficient production of tens of milligrams of pure protein from 1-liter cultures. Caltractin has a distinct UV spectrum which is largely dominated by the fine structure due to the 9 Phe residues. Unlike other members of the same protein family, the UV and the CD spectra do not change upon addition of Ca2+ to the apoprotein. However, the 1H NMR spectrum shows distinct changes upon Ca2+ binding, which are indicative of structural and/or dynamic changes largely reminiscent of other members of the calmodulin superfamily. Ca2+ binding measurements demonstrated the binding of four Ca2+ ions to caltractin with two higher affinity (Kd = 1.2 x 10(-6) M) and two lower affinity (Kd = 1.6 x 10(-4) M) sites. Caltractin is highly stable in both the apo- and the Ca(2+)-loaded states. The unusual stability of apocaltractin makes this protein highly suited for structural studies by multidimensional NMR aimed at understanding the structural and dynamic consequences of Ca2+ binding, and the molecular basis of Ca2+ signal transduction.

Amino Acid Sequence↗

PubMed1994

A survey of actinic keratoses among paraquat production workers and a nonexposed friend reference group.

Follow-up on two reports of an excess of keratoses among paraquat production workers was conducted to evaluate the contribution of occupational exposures to the prevalence of keratoses among workers in a paraquat production plant in Texas. A cross-sectional study design was used to compare the prevalence of keratoses among current workers to an age, race, and sex frequency-matched group of their friends who had never worked at the plant. The analysis is based on 112 workers and 232 friends. Exposure, outcome, and covariables used in the analyses were obtained from an interview questionnaire, dermatology exam, and company records. Overall, the prevalence proportion of the presence of any actinic keratoses among workers and friends was similar (0.30 and 0.28, respectively). Among high cumulative exposed workers, the prevalence of any actinic keratoses was 0.40 compared to 0.20 among low-exposed workers and 0.28 among friends. These results were further explored using a multiple logistic regression approach to adjust for known risk and possibly confounding variables. Statistically significant high risks of actinic keratoses were demonstrated for freckling before age 16 years, older age, suntanning behaviors, occupational exposure to polycyclic aromatic hydrocarbons (PAH), and Fitzpatrick skin type. There was no significant contribution of overall exposure status (worker vs. friend). Similar to the crude analysis, the odds of actinic keratoses of high-exposed workers compared to friends was 1.9 (confidence interval [CI] = 0.9-4.2) whereas the comparable odds ratio for low-exposed workers vs. friends was 0.6 (CI = 0.2-1.7). These data do not demonstrate an excess of actinic keratoses overall nor any consistent increase in the odds of keratoses with an increase in plant exposure level.

Adult↗

PubMed1994

Expression of the BnmNAP subfamily of napin genes coincides with the induction of Brassica microspore embryogenesis.

Brassica napus cv. Topas microspores can be diverted from pollen development toward haploid embryo formation in culture by subjecting them to a heat stress treatment. We show that this switch in developmental pathways is accompanied by the induction of high levels of napin seed storage protein gene expression. Changes in the plant growth or microspore culture conditions were not by themselves sufficient to induce napin gene expression. Specific members of the napin multigene family were cloned from a cDNA library prepared from microspores that had been induced to undergo embryogenesis. The majority of napin clones represented three members (BnmNAP2, BnmNAP3 and BnmNAP4) that, along with a previously isolated napin genomic clone (BngNAP1), constitute the highly conserved BnmNAP subfamily of napin genes. Both RNA gel blot analysis, using a subfamily-specific probe, and histochemical analysis of transgenic plants expressing a BngNAP1 promoter-beta-glucuronidase gene fusion demonstrated that the BnmNAP subfamily is expressed in embryogenic microspores as well as during subsequent stages of microsporic embryo development.

2S Albumins, Plant↗

PubMed1994

Reorganization and condensation of chromatin in mitotic prophase nuclei of Allium cepa.

This paper studies the process and features of chromosome construction in mitotic prophase cells of Allium cepa. The results showed that a prominent reorganization of chromatin occurred during G2--early prophase. The 250-400 nm thick compact chromatin threads in G2 nuclei began to disorganize into about 30, 100 and 220 nm chromatin fibres which constituted the loosely organized chromosome outlines in early prophase before chromosome condensation. In middle prophase, chromosome condensation was characterized by the formation of many condensed regions (aggregates of chromatin), which increased in size (1-1.5 microns) when prophase proceeded. Meanwhile, the chromatin threads that constituted and connected the condensed regions became increasingly thicker (120-250 nm). In late prophase adjacent condensed regions fused to form cylinder-shaped chromosomes. Based on these observations, we come to the conclusion that the construction of prophase chromosomes is a two-step process, that is, the reorganization and condensation of chromatin. In addition, we report the study of silver-stained, DNA- and histone-depleted prophase chromosomes, describe morphological features of the non-histone protein (NHP) residue in early, middle and late prophase chromosomes, and discuss the roles of NHPs in chromosome construction.

Allium↗

PubMed1994

Micturition patterns after spinal trauma as a measure of autonomic functional recovery.

The purpose of these experiments was to determine whether experimental spinal trauma would result in urological dysfunction similar to that seen clinically and whether recovery of normal micturition can be correlated with motor functional recovery. A standard rat model of spinal impact trauma was employed. Neurologic evaluation included a modified 7 point hindlimb Tarlov scale applied weekly for 4 weeks after injury. Micturition measurement was accomplished by placing the animal in a metabolic cage for 24-hour periods and collecting urine on an electronic scale connected to Lotus Measure data acquisition software. All assessments were performed in a blinded fashion. Animals were categorized as normal control (N = 10), sham injured (N = 11), spinal cord injury (SCI) without (N = 11) and with locomotor recovery (N = 11). There were no differences in total micturition volume among the 4 groups, while the number of micturitions per 24 hours was significantly less for SCI without locomotor recovery (10.4 +/- 5.9) than for control (21.3 +/- 4.5). The volume per micturition was significantly greater for SCI (2.0 +/- 0.7 ml.) than for control (0.8 +/- 0.2 ml.). There were no differences among groups in the ratio of number of micturitions night/day. The SCI group had significantly greater largest and smallest micturitional volumes. Results clearly show alterations in micturition patterns induced by SCI. These were proportional to, but did not correlate fully with, the severity of injury and degree of motor recovery. Thus, recovery of a normal micturition pattern did not occur to the same extent as did motor functional recovery. This difference underscores the potential value of autonomic measures of SCI for distinguishing outcome categories after experimental SCI.

Analysis of Variance↗

PubMed1994

Rise of blood pressure with age. New evidence of population differences.

Epstein and Eckoff in 1967 devised a scheme to summarize population differences in the rise of mean values of systolic blood pressure by age in accordance with their slopes and levels. For the first time, the validity of this scheme can be examined with data from a single study, INTERSALT. This study included 52 populations in 32 countries. On the basis of these data, collected in an exceptionally well-standardized mode under a common protocol, the diversity of populations in the slopes of age differences in median values of systolic blood pressure has been strongly reconfirmed. Populations with no increase in median systolic blood pressure were again observed and remained exceptional. The analyses of these data also indicate a positive relation between the slope of rising systolic blood pressure with age and urinary sodium, urinary sodium-potassium ratio, and reported alcohol consumption as well as a negative association between urinary potassium excretion and blood pressure slope. The present analyses therefore add to the previous knowledge and results published by the INTERSALT investigators in the following three respects: (1) they relate INTERSALT results to the postulated biological gradient of variation among populations as presented by Epstein and Eckoff, including explanatory variables; (2) they demonstrate strong correlation between ranks of median blood pressure at 40 to 49 years and values at 20 to 29 years; and (3) they therefore support the original Epstein and Eckoff concept of population variation, link this with blood pressure risk factors, and call attention to the large degree of population differences already evident among populations at 20 to 29 years of age.

Adult↗

PubMed1994

Hafnia alvei. Respiratory tract isolates in a community hospital over a three-year period and a literature review.

In a retrospective review, a group of seven patients were found to have a sputum culture positive for Hafnia alvei. Hafnia alvei is a Gram-negative enteric and oropharyngeal bacillus and usually is nonpathogenic. All our patients had a chronic underlying illness and one of the patients was endotracheally intubated at the time of the isolation of this organism. Six of seven patients had other organisms isolated along with H alvei, and only one patient had a pure growth of H alvei confirmed by a culture obtained from a bronchoscopic protected brush specimen. All isolates displayed resistance to conventional antibiotics including cephalosporins and penicillins. Although rare, H alvei may be a potential pathogen in a patient with a chronic underlying illness.

Adult↗

PubMed1994

[Amplification, cloning and sequencing of beta nerve growth factor gene in the Chinese population].

Genomic DNA was extracted from white blood cells. Using the genomic DNA as template, the gene encoding nerve growth factor (beta-NGF) in the Chinese population was amplified using polymerase chain reaction (PCR). The beta-NGF gene obtained by PCR was then cloned into plasmid pUC 12 which was digested with SmaI. After transformation, screening and identification, 8 clones containing the beta-NGF gene were analyzed. Nucleotide sequence of the NGF was determined by dideoxy-nucleotide chain-termination method. The sequencing result showed that there are 6 differences between the beta-NGF sequence of the Chinese population and previous reported beta-NGF sequence.

Amino Acid Sequence↗

PubMed1994

[The effect of medical treatment on hypertension community control--a follow-up study of more than one thousand hypertensives in East City Proper, Beijing].

Hypertension exerts a great threat on human health. Although most of countries promote the management of hypertension in communities, the role of treatment of hypertension is still controversial, it directly influences the strategy of hypertension community control. This study was based on the survey of essential and borderline hypertension in Gu-lou District of East City Proper, Beijing in 1981, and the management of 1339 hypertensives in the follow-up from 1982 to 1985, and the mortality registration in the district by Disease Surveillance System. By observing the prognosis within one year among different treatment groups (nonusers, less than 9 months and more than 9 months within one year), 1289 patients were followed up for a total of 4283 person-years. Crude analyses, stratified and logistic analyses with multi-variables adjustment of age, sex, blood pressure, with or without end-organ damage, etc. could not find that treatments had obvious effects on the reduction of incidence and mortality of stroke, mortality of CVD and all-cause in hypertensives except severe cases. The stratified analyses dy smoking also showed that smoking had a disadvantageous effects for treated hypertensives. Based on our results, we suggest that health education should be a major part of hypertension management program in community; treatments of hypertension should consider the flexible situation of patients and may not be a priority in hypertension community control program.

Aged↗