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Biomedical subjects

Z He

Publications and source records attributed to Z He.

At least 217 records · Page 12Linked to original sources

The transactivator proteins VP16 and GAL4 bind replication factor A.

Many transcription factors can activate the initiation of DNA replication. We have used affinity chromatography to show that the acidic activation domains of the transcription factors VP16, GAL4, and p53 each bind selectively to human and yeast replication factor A (RPA). The binding is direct and to the largest subunit of the trimeric RPA complex, RPA-1. Mutations in VP16 that reduce the ability of GAL4-VP16 to activate polyomavirus DNA replication also compromise the binding of VP16 to RPA. We suggest that transcription factors may interact with RPA either to stabilize single-stranded DNA at a replication origin or to recruit DNA polymerase alpha to the replication initiation complex.

DNA-Binding Proteins↗

Hydroxyl radical production in the reactions of copper-containing amine oxidases with substrates.

Solutions of porcine kidney diamine oxidase, PKDAO, and bovine plasma amine oxidase, BPAO, were saturated with the spin-trapping agent alpha-phenyl-N-t-butylnitrone, PBN, and incubated with cadaverine or benzylamine substrate, respectively, under aerobic conditions. EPR spectra due to trapped hydroxyl radicals were obtained for both enzymes with no evidence of superoxide formation. Under anaerobic conditions, hydroxyl radicals were formed only when H2O2 was present as well as substrate. Catalase prevented hydroxyl radical formation by PKDAO but not BPAO. The results indicate that hydroxyl radical is produced in the reaction of the product H2O2 with the reduced enzymes and therefore may be important in turnover-related enzyme degradation, but is not a true reaction intermediate.

Amine Oxidase (Copper-Containing)↗

Aneuploidy induction by water extract from Tripterygium hypoglaucum (Level) Hutch in mouse bone marrow cells.

The aneuploidy-inducing activity of a Chinese medicinal herb, Tripterygium hypoglaucum (level) Hutch (THH), was investigated by means of three cytogenetic end-points, i.e. C-mitotic (CM) effects, micronuclei (MN) and parallel chromosome structural aberration (CA) analyses in vivo. The CA analysis was expected to reflect the origins of MN induced by clastogens or aneugens. The experiments were performed on mouse bone marrow cells. The animals were treated with the crude water extracts of THH (single i.p. injection) in the dose range 120-686 mg/kg. Colchicine (COL) was taken as a positive control for its known aneuploidy-inducing effects. THH showed similar genotoxic effects to COL in CM, MN and CA analyses: positive CM effects were observed accompanied with increases of mitotic index and frequencies of CM cells as well as decreased frequencies of anaphase in all of the THH-treated groups. The compound showed a positive MN response in bone marrow polychromatic erythrocytes but was negative in CA analyses. No sex differences were found in any treated group. The preliminary results suggested that THH is an aneuploidy inducer in mouse bone marrow cells under the present experimental conditions.

Aneuploidy↗

[Role of musculocutaneous nerve in the relationship between "chutse" acupoint and heart].

Ligating fourty eight rabbits left ventricular branch of coronary artery made model of acute myocardial infarction (AMI) with indices of ECG and size of AMI. They were divided at random into four groups: "Chutse" acupoint group, cutting musculocutaneous nerve of "Chutse" acupoint group, cutting musculoutaneous nerve group, control group. Results showed that there is no role in laser acupuncture at "Chutse" acupoint for reducing myocardial injury and size of AMI after cutting musculocutaneous nerve of "Chutse" acupoint. It is illustrated that the musculocutaneous nerve might play an important role in the relationship between "Chutse" acupoint and heart.

Acupuncture Points↗

[Histochemical studies of cutaneous lichen amyloidosis using light and electron microscopy].

Ten cases of cutaneous lichen amyloidosis are reported. Amyloid deposits were found to be limited to the papillary dermis. The amyloid masses were often fissured and had an amorphous eosinophilic globular appearance. The protein was confirmed by histochemistry as amyloid-associated protein. The epidermal origin of the amyloid deposit has been confirmed by electron microscopy. The amyloid deposit was of variable island structure, accompanied by filaments.

Adult↗

Catheter obstruction with omental wrap stimulated by dialysate exposure.

A new implantation technique and catheter design (Moncrief-Popovich Catheter) were tested in the continuous ambulatory peritoneal dialysis (CAPD) dog model. With this technique the catheter distal (external) segment was implanted in a subcutaneous tunnel for 4-6 weeks. Therefore, no irrigation of exposure to dialysate was present. Secondary exteriorization and irrigation (CAPD exchanges) demonstrated no episodes of primary catheter obstruction. Fifteen mongrel female dogs had 30 catheters implanted; 2 catheters simultaneously in each dog. One catheter was implanted with the interabdominal segments in the pelvis and the second interabdominal segment directed upward in direct contact with the omentum. Following initial irrigation, all catheters were patent, but within 24-48 hours all upwardly directed catheters were obstructed. Nine of the 15 downwardly directed catheters became obstructed by omentum wrapping around the catheter within 5 days. Preliminary studies have failed to demonstrate the cause of this "omental stimulation," which occurs with peritoneal contact with fresh dialysate. Possible explanations include pH, osmolality, flow direction, volume, vasodilator effect of osmols or lactate, and glucose, among others. This effect needs study, and this model would allow evaluation of improvements in the biocompatibility of dialysis fluids.

Animals↗

Molecular cloning, nuclear gene structure, and developmental expression of NADPH: protochlorophyllide oxidoreductase in pea (Pisum sativum L.).

Complementary DNA clones and a corresponding nuclear gene (lpcr) encoding the NADPH-dependent protochlorophyllide oxidoreductase (pchlide reductase, EC 1.6.99.1) have been characterized from pea (Pisum sativum L.). The pea lpcr gene encodes a 43,118 Da precursor polypeptide comprised of a transit peptide of 64 amino acids and a mature protein of 336 amino acids. The coding portion of the gene is interrupted by four introns, two of which are located within the transit peptide coding portion of the gene. The deduced primary structure for the pea protein is similar to those reported for Arabidopsis and two monocot species. Northern blot analysis revealed little to no decrease in steady-state levels of mRNA encoding the enzyme in etiolated leaves illuminated with continuous white light for up to 48 h. In contrast, western blot analysis showed that the major immunoreactive species present in whole leaf extracts decreased to nearly undetectable levels during this same 48 h period. These results suggest that pchlide reductase activity in pea is primarily regulated post-transcriptionally, most likely at the level of translation initiation/elongation or protein turnover.

Amino Acid Sequence↗

Clinical evaluation of 99mTc-MIBI myocardial tomography for detecting coronary artery disease.

To evaluate the clinical efficacy of 99mTc-MIBI myocardial tomography for detecting coronary artery disease, 34 consecutive patients who underwent both 99mTc-MIBI study and coronary arteriography were included in the present study. Ten without and 24 with significant coronary artery disease were documented by coronary arteriography. The overall sensitivity and specificity of 99mTc-MIBI study for detecting coronary artery disease were 91.8% (22/24) and 80.0% (8/10), respectively. In subset studies, 16 of 17 (94.1%) patients with previous myocardial infarction and 6 of 7 (85.7%) patients with significant CAD but without MI were identified as abnormal. Reversible perfusion abnormalities were shown in 4 of 5 patients undergoing both exercise and rest studies. Rest perfusion abnormalities were shown in 2 patients with unstable angina pectoris who underwent only rest study. In conclusion, 99mTc-MIBI myocardial tomography provides a reliable method for detecting coronary artery disease. Rest study has high sensitivity for identifying patients with MI, and exercise/rest study can identify patients with significant CAD but without MI.

Coronary Disease↗

NADPH: protochlorophyllide oxidoreductases in white pine (Pinus strobus) and loblolly pine (P. taeda). Evidence for light and developmental regulation of expression and conservation in gene organization and protein structure between angiosperms and gymnosperms.

NADPH: protochlorophyllide oxidoreductase (pchlide reductase, EC 1.6.99.1) catalyzes the light-dependent reduction of protochlorophyllide in higher plants. Cloned cDNAs encoding two distinct pchlide reductases were isolated from a lambda gt11 library constructed from poly(A)+ RNA prepared from the cotyledons of dark-grown white pine (Pinus strobus) seedlings and a nuclear gene (lpcr) analogous to one of these cDNAs has been characterized from loblolly pine (P. taeda). The pine gene encodes an approximately 43 kDa precursor polypeptide consisting of a 334-amino acid mature protein and a 66-amino acid transit peptide. The deduced primary structures for the pine proteins are highly homologous to those reported from monocots and dicots. The coding portion of the pine lpcr gene is interrupted by four introns. The placement of these introns within the pine lpcr gene is identical to that observed in pea (Pisum sativum), suggesting conservation in gene organization between dicot and gymnosperm species. Western blot analysis using polyclonal antiserum against oat pchlide reductase detected in extracts of dark-grown pine cotyledons a single immunoreactive protein, which declined in abundance during a 48 h period of illumination with white light. Cotyledons of dark-grown seedlings were also found to accumulate high levels of pchlide reductase mRNA; however, little or no change in the steady-state levels of mRNA encoding pchlide reductase was observed in these tissues following illumination. Stem tissue of dark-grown seedlings did not contain significant levels of pchlide reductase mRNA, whereas stems of light-grown plants of the same age accumulated substantial amounts of the message. These results suggest that light and the developmental age of the tissue affect regulation of lpcr expression in pine.

Amino Acid Sequence↗

cDNAs encoding members of a family of proteins related to human sterol carrier protein 2 and assignment of the gene to human chromosome 1 p21----pter.

Sterol carrier protein 2 (SCP2) is believed to play a key role in intracellular lipid movement. Here we report the cloning and nucleotide sequences of cDNAs encoding SCP2-related proteins of 58.85 kD and 30.8 kD and the assignment of the SCP2 gene to human chromosome 1 p21-pter. The SCP2-related proteins share common deduced carboxyl amino acid sequences with SCP2 and the cDNAs have a common 3' untranslated nucleotide sequence. The mRNAs encoding these proteins increased in a coordinate fashion as human placental cytotrophoblasts differentiated into syncytiotrophoblasts in culture. Our observations document the existence of a family of related proteins encoded by the human SCP2 gene.

Amino Acid Sequence↗

[Studies of rapid detection of drug-resistance of Mycobacterium by gas chromatography].

This test is based on the physiologic character of mycobacterium, which produces carbon dioxide (CO2) during its growth, Löwenstein-Jensen media CO2 contents-were measured by gas chromatography for determining drug-resistance of mycobacteria. This was compared with the routine method. Seventy-eight mycobacteria were isolated from suspected tuberculosis patients for the experiment. Our data suggested that the accordance rates of both methods were 83.3%. Gas chromatography is a simple, rapid and accurate method for detecting drug-resistance. The results can be obtained twenty days earlier than by the routine method.

Antitubercular Agents↗

[The clinical use of sodium hyaluronate eyedrops as a substitute for tears].

The present paper reports on the curative effect of the 0.1% Sodium hyaluronate (Na-HA) eyedrops jointly manufactured by Guangzhou Red Cross Hospital and Guangzhou Institute of Medical & Pharmaceutical Industry. 70 cases were studied. There were kerato-conjunctivitis sicca, lagophthalmos corneal fluorescein diffuse punctate epithelial lesion caused by contact lens, and keratitis punctata superficialis. The results showed effective treatment which occupied 95.7%. In the discussion, the authors point out that Na-HA has the same stagnatisity and elasticity as biotears because of its adhesion to the corneal epithelium. Moreover, it has the water-retaining microsponge action similar to that of mucopolysaccharide. Hence, Na-HA has protective effects on corneal epithelium. Finally, the authors conclude that Na-HA eyedrop is so far the most ideal substitute for tears and superior to other artificial tears.

Adult↗

The use of alprostadil sterile powder in a home self-injection study of Asian men with erectile dysfunction.

This study evaluated the individual optimal dose of alprostadil in the office setting that could be used as the basis for effective home self-injection therapy. The study included 150 Asian men with erectile dysfunction (ED). The mean age of study participants was 48.3 years (range, 21 to 74 years), and the mean duration of ED was 3.6 years. The most common cause of ED was venogenic (24%), psychogenic (21%), arteriogenic (13%), neurogenic (0.7%), or a combination of these (41%). An optimal response was seen in 72% of patients (n = 108) in the office and 96% of patients (n = 100) at home. The mean +/- SD office dose of alprostadil was 19.4 +/- 12.8 micrograms versus 18.0 +/- 12.2 micrograms at home. More than half of the patients (57% in an office setting and 53% at home) achieved an optimal response at a dose between 5 and 15 micrograms. By the 20-micrograms dose, 82% of patients had achieved an optimal dose at home compared with 70% of patients in the office. An optimal response was seen at the same dose in the office and home in 75% of patients; the dose at home decreased from the office dose for 16% of the patients and increased for 9%. There were 24 patients who experienced adverse events: penile pain after injection (18 patients), cold sweating (2 patients), pediculosis (1 patient), broken leg (1 patient), ankle pain (1 patient), and prolonged erection (1 patient). One patient discontinued the study because of penile pain. Alprostadil sterile powder offered safe and effective treatment of ED for home self-injection therapy. Once an optimal dose response had been established in the physician's office, further home adjustments were needed in 25% of patients. Penile pain, usually mild, was the most common, possibly related adverse effect reported.

Adult↗

Air pollution-type fluorosis in the region of Pingxiang, Jiangxi, Peoples' Republic of China.

This paper reports on the epidemiology, environmental factors, geological features, and total amount of fluoride intake by residents of the Pingxiang region in the Peoples' Republic of China where there is a high incidence of endemic fluorosis. The results demonstrate that the type of endemic fluorosis is related to air pollution, the major source of which comes from coal that is burned by the residents in their homes. Air pollution also originates from the small kilns that are used to make bricks and tile. The fluorine content in the coal and mud used to mix the coal is considerably high; the content in the mud used as adobe for tiles exceeds 10,000 mg/kg. During the process of burning coal or baking bricks or tiles, a large amount of nonsoluble fluorine is converted into water-soluble fluoride, which can have major human health effects.

Adolescent↗

Peritoneal membrane plasmapheresis.

A novel process has been devised that uses the peritoneal membrane to remove plasma proteins from the body at a rate comparable to conventional extracorporeal plasma-pheresis. A vasodilator (4 mg histamine phosphate) is added to 1 liter of hypertonic solution (485 mOsmol/L), and infused intraperitoneally with a residence time of 4 hr. Plasma containing proteins is convected across the peritoneum through open pores into the cavity and removed. The next alternating infusion is with a hypotonic solution (214 mOsml/L) containing a vasoconstrictor (1.0 mg norepinephrine). This infusion restores the fluid removed from the subject in the previous exchange, and prevents the rapid fall-off in protein removal rates obtained with repeated infusions with vasodilators only. Peritoneal membrane plasmapheresis was successfully tested on canines, with protein removal rates of between 30% and 50% of total serum protein per day for 13 days over a 22 day period. Peritoneal membrane plasmapheresis represents a potentially inexpensive, continuous/nightly home treatment for protein mediated diseases treatable by extracorporeal plasmapheresis.

Animals↗

Filter banks and neural network-based feature extraction and automatic classification of electrogastrogram.

Dysrhythmia in gastric myoelectrical activity has been frequently observed in patients with gastric motor disorders and gastrointestinal symptoms. The assessment of the regularity of gastric myoelectrical activity is of great clinical significance. The aim of this study was to develop an automated assessment method for the regularity of gastric myoelectrical activity from the surface electrogastrogram (EGG). The method proposed in this paper was based on the filter bank and neural network. First, the EGG signal was divided into frequency subbands using filter bank analysis. Second, a parameter called the subband energy ratio (SER) was computed for each subband signal. A multilayer perceptron neural network was then used to automatically classify the EGG signal into four categories: bradygastria, normal, tachygastria, and arrhythmia, using the SER as the input. The EGG recording was made using the standard method of electrogastrography by placing electrodes on the abdominal surface. The study was performed in 40 patients with various gastric motor disorders, ten healthy adults, and ten healthy children. The neural network was trained and tested using the EGG data obtained from the patients. The regularity of gastric myoelectrical activity was assessed based on the classification of the minute-by-minute EGG segments. Using the running spectral analysis method as a gold standard, the proposed automated method had an accuracy of 100% for the training set and 97% for the test set. It was concluded that the proposed method provides an accurate and automatic assessment of the regularity of gastric myoelectrical activity from the EGG.

Adolescent↗