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Biomedical subjects

H Fang

Publications and source records attributed to H Fang.

At least 73 records · Page 4Linked to original sources
PubMed1998

Activation of the Jak2-Stat5 signaling pathway in Nb2 lymphoma cells by an anti-apoptotic agent, aurintricarboxylic acid.

Biological effects of many hormones and cytokines are mediated through receptor-associated Jak tyrosine kinases and cytoplasmic Stat transcription factors, including critical physiological processes such as immunity, reproduction, and cell growth and differentiation. Pharmaceuticals that control Jak-Stat pathways are therefore of considerable interest. Here we demonstrate that a single Jak-Stat pathway can be activated by aurintricarboxylic acid (ATA), a negatively charged triphenylmethane derivative (475 Da) with anti-apoptotic properties. In prolactin (PRL)-dependent Nb2 lymphocytes, ATA sustained cell growth in the absence of hormone and mimicked rapid PRL-induced tyrosine phosphorylation of Jak2 and activation of Stat5a and Stat5b with tyrosine phosphorylation, heterodimerization, DNA binding, and induction of the Stat5-regulated pim-1 protooncogene. ATA also mimicked PRL activation of serine kinases ERK1 and ERK2. However, unlike PRL, ATA did not regulate Stat1 or Stat3. ATA also did not affect Jak3, which is activated in these cells by interleukin-2 family cytokines. Although the mechanism and specificity by which ATA activates Jak2, Stat5, and ERKs in Nb2 cells are still unclear, the present study demonstrates that certain hormone or cytokine effects on Jak-Stat pathways can be discretely imitated by a low molecular weight, non-peptide pharmaceutical. The results are also consistent with Stat5 involvement in lymphocyte growth and survival.

Apoptosis↗
PubMed1998

Secondary coverage of the yolk by the body wall in the direct developing frog, Eleutherodactylus coqui: an unusual process for amphibian embryos.

Eleutherodactylus coqui develops directly from a large 3.5-mm egg to a froglet, without an intervening tadpole stage. We have examined the development of the body wall, a structure whose behavior has been altered in this derived development. In an event that is unusual for amphibian embryos, the yolk mass is secondarily surrounded by the body wall, which originates near the embryo's trunk. The epidermis of the body wall is marked by melanophores, and the rectus abdominis, which will form the ventral musculature, is near its leading edge. As the body wall expands, the epidermis, melanophores, and rectus abdominis all move from the dorsal side to close over the yolk at the ventral midline. The original ectoderm over the yolk undergoes apoptosis, as it is replaced by body wall epidermis. Intact muscles are not required for ventral closure of the body wall, despite their normal presence near the advancing edge. Comparative examination of embryos of Xenopus laevis and Rana pipiens suggests that ventral closure does not occur in species with tadpoles. The expansion of dorsal tissues over the yolk, as illustrated by E. coqui, may have been important in the origin of amniote embryos.

Animals↗
PubMed1997

Differential labeling of dopamine and sigma sites by [3H]nemonapride and [3H]raclopride in postmortem human brains.

The difference between the binding of [3H]nemonapride and [3H]raclopride has been used to quantify dopamine D4 receptors in postmortem schizophrenic brain studies. Recent work, however, has suggested that at least part of the differential between [3H]nemonapride and [3H]raclopride binding may represent sigma rather than D4 receptor sites. We applied the nemonapride-raclopride subtraction method to postmortem, non-schizophrenic human striatum to examine the variation in dopaminergic receptor binding labeled by these ligands. Variation in sigma receptor binding labeled by [3H]nemonapride was studied in frontal cortex, striatum and cerebellum. Specific binding was defined by sulpiride (dopamine receptor ligand), PPAP (sigma receptor ligand) and haloperidol (mixed dopaminergic/sigma agent), respectively. Haloperidol defined a combination of sites, which were approximately the sum of the dopaminergic and sigma components defined by sulpiride and PPAP, respectively. Significant inter-individual variation in the amount of specific binding for dopaminergic and sigma receptor sites was observed. However, no significant nor consistent observation of striatal dopamine D4 receptors or D4-like binding sites was observed in the striatum even though two independent sets of tissues, with different dissections were used. The inconsistencies in some previous postmortem studies appear to be at least partially explained by the inclusion of both sigma and dopaminergic components in [3H]nemonapride binding and the inherent high inter-individual variability of the different components.

Adult↗
PubMed1997

In addition to SEC11, a newly identified gene, SPC3, is essential for signal peptidase activity in the yeast endoplasmic reticulum.

Among the three characterized subunits comprising the signal peptidase complex of the yeast Saccharomyces cerevisiae (Sec11p, Spc1p, and Spc2p), only Sec11p is essential for cell growth, signal peptide cleavage, and signal peptidase-dependent protein degradation. Here we report the cloning of the SPC3 gene encoding the homolog to mammalian signal peptidase subunit SPC22/23. We find that Spc3p is also required for cell growth and signal peptidase activity within the yeast endoplasmic reticulum.

Amino Acid Sequence↗
PubMed1997

Metallothionein gene expression in embryos of the sea urchin Lytechinus pictus.

The metallothionein (MT) gene LpMT1 of the sea urchin Lytechinus pictus was characterized. The primary transcript of 3042 nucleotides includes four exons, as uniquely observed for other sea urchin MT genes, which are spliced to form a messenger RNA of 605 nucleotides. The deduced LpMT1 protein sequence includes 69 amino acids, more than observed for other MT proteins. For a high level of inducible activity, the LpMT1 promoter requires sequence elements in addition to the canonical regulatory elements identified for mammalian MT promoters. The promoter of the closely related LpMT2 gene is very active in spite of its lack of a distinctive poly(C) element included in a sequence tract required for fully induced activity of the LpMT1 promoter. In contrast to embryos of the sea urchin S. purpuratus in which MT mRNAs are restricted to the aboral ectoderm of uninduced embryos, no spatially preferential accumulation of MT mRNAs in L. pictus embryos was observed. The cisacting regulatory elements required for MT gene activity and the spatial specificity of MT gene expression in sea urchin embryos are considered. The LpMT1 and LpMT2 promoters constitute promiscuous promoters that can be induced to a high level of activity.

Amino Acid Sequence↗
PubMed1997

Clinical application of retrograde island flap pedicled with lateral plantar artery.

The purpose of the study is to identify a repair procedure for the ulcers or defect of the anterior lateral plantar region. The defects of anterior lateral plantar region after resection of the obstinate ulcer, painful corns and callosity were repaired by the retrograde island flap pedicled with lateral plantar artery. One to 10 years following up revealed that all the 10 flaps in 9 patients survived after operation. Patients walked freely without pain and claudication. The flap did not show any sign of damages of the flap even if the patients walked for a long time. It is concluded that the retrograde island flap pedicled with lateral plantar artery is the best choice in repairing the defects of anterior lateral plantar region.

Adolescent↗
PubMed1997

Multiple [3H]-nemonapride binding sites in calf brain.

[3H]-Nemonapride has been the ligand of choice to label D4 dopamine receptors. Its specificity was questioned when it was discovered that sigma (sigma) sites were also labeled by [3H]-nemonapride. To further characterize the binding of [3H]-nemonapride, three areas of calf brain (striatum, frontal cortex and cerebellum) were examined. In all three areas, [3H]-nemonapride labeled multiple sites. Dopaminergic and sigma sites were the most prominent. The sigma binding profile was sigma-1 like with a Ki binding profile as follows (in order of decreasing potency): haloperidol, PPAP, pentazocine, DTG, U-50488, R(+)-3-PPP. Experiments using sulpiride and pentazocine to block striatal dopaminergic and sigma sites, respectively, revealed additional, not previously characterized binding sites for [3H]-nemonapride. One component which was present in striatum but not in frontal cortex or cerebellum, had affinity for some neuroleptics and WB-4101, but not for typical serotonergic agents. Thus, [3H]-nemonapride has no selectivity for dopamine receptors unless stringent experimental conditions are met.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1997

Isoforms of gp138, a cell-fusion related protein in Dictyostelium discoideum.

Sexual development of Dictyostelium discoideum is a unique and useful system for the study of sexual phenomena. We have been studying molecular mechanisms of sexual cell fusion in D. discoideum and have identified several relevant cell-surface proteins. One of the proteins, gp138, was identified as a target molecule for fusion-blocking antibodies, and two genes for gp138, GP138A and GP138B, were cloned. The participation of gp138 in the sexual cell fusion was confirmed by antisense RNA mutagenesis, but it is unclear which of the genes encodes gp138. Moreover, the presence of a third gene for gp138 was indicated by gene disruption. In the present study, we generated strains of D. discoideum overexpressing either GP138A or GP138B to investigate the products of these genes. The transformants overexpressing GP138A and GP138B overproduced glycoproteins with molecular masses of 135 and 130 kDa, respectively. Although their molecular masses were different from that of gp138, the results of peptide mapping and amino acid sequencing showed that they are related to proteins, suggesting that the proteins encoded by GP138A and GP138B are isoforms of gp138 protein.

Amino Acid Sequence↗
PubMed1997

[Investigation on the resources of medicinal centipedes and identification on their commodities].

Through investigation on the resources of medicinal centipedes and identification on corresponding medicinal materials, the original animals of medicinal centipedes are Scolopendra mutilans, S. multidens, S. mojiangica and S. negrocaptis. The main commercial medicinal centipede is S. mutilans. Its yield accounts for 95%. This paper arranged the retrieve tables of the morphological characters of original animals and commercial materials of medicinal centipedes.

Animals↗
PubMed1997

[Hemolysis of Scolopendra toxins].

The hemolysis of toxins from alive Scolopendra subspinipes mutilans, medicinal material of Scolopendra subspimipes mutilans and S. multidens have been compared. The result shows that all the toxins have hemolytic activity. The hemolytic activity of the toxin from the medicinal materials of S. subspinipes mutilans is obviously lower than that from alive ones, and that from fresh medicinal materials are twice as high that from old ones, and that from S. multidens is higher than that from S. subspinipes multilans.

Animals↗
PubMed1997

Acceptance, efficacy, and side effects of Norplant implants in four counties in north China.

This report attempts to present a comprehensive analysis of the acceptability, side effects, and efficacy of Norplant as used in rural areas, based on a field experiment conducted in four counties in Hebei and Shandong Provinces, China. The initial acceptance of Norplant was relatively high but waned after the first year in three of the four counties. Compared with clinical trials, the current study shows a lower prevalence but similar patterns of side effects. The pregnancy rate during the first two years of use is similar to that found in large-scale clinical trials conducted in China, but discontinuation due to other reasons is lower. A three-level logistic regression analysis shows significant variation in the probability of discontinuation due to side effects across counties. It also indicates an increase in the conditional probability of discontinuation with the duration of use. Whereas introducing Norplant and achieving a very low failure rate and high continuation rate in rural areas is feasible under diverse socioeconomic conditions, the results vary significantly across different areas. Particular attention should be paid to the local factors that may affect results.

Adult↗
PubMed1997

[Relation of Lac promotor and the expression of cholera toxin subunit B gene in recombinant Escherichia coli MM2].

Effects of different carbon sources including glucose, lactate and acetate and IPTG induction on the expression of ctb gene, which is on the downstream of lac promotor, in recombinant Escherichia coli MM2 were studied. In medium YC were added 0.048mol/L glucose, 0.102mol/L lactate or 0.167mol/L acetate which separately produce the same energy in the condition of complete oxidization. Addition of glucose largely decreased the expression level of ctb gene because of decrease of pH during culture process. Addition of lactate increased the expression level of ctb gene by 1.15 fold and did not inhibit the growth of MM2 strain. Addition of acetate increasd the expression level of ctb gene by 0.97 fold and inhibited the growth of MM2 strain. Induction by IPTG at different time and different concentration did not increase the expression level of ctb gene, so the lac promotor had no or a little influence upon the expression of ctb gene in recombinant MM2 strain.

Acetates↗
PubMed1997

[Clinical application of retrograde island flap carrying plantar metatarsal arteries as pedicle].

The skin and soft tissue defects or ulceration of the wight-bearing part of the sole was difficult to repair with medial plantar island flap, but would be treated with retrograde island flap carrying plantar metatarsal arteries as pedicle. Ten flaps were applied in 9 patients. They had either indolent ulcer or skin defect secondary to excision of painful corn or callosities of the front part of the sole. The flaps were 3 cm to 5 cm long and 3 cm to 4 cm wide, and they all survived following retrograde transfer. The patients were followed up for 1 to 10 years. It was found that the patients could bear weight on the operated foot and could walk without pain or lameness. The flaps were resistant to abrasion from long-time walking. It was concluded that this kind of flap was best suitable to repair the ulcers and defects over the front part of the sole despite there were some minor shortcomings such as the size of the flaps available was small and the donor site required split skin graft for coverage.

Adolescent↗
PubMed1997

[Preliminary investigation of treatment of ulnar nerve defect by end-to-side neurorrhaphy].

In the repair of the defect of peripheral nerve, it was necessary to find an operative method with excellent therapeutic effect but simple technique. Based on the experimental study, one case of old injury of the ulnar nerve was treated by end-to-side neurorraphy with the intact median nerve. In this case the nerve defect was over 3 cm and unable to be sutured directly. The patient was followed up for fourteen months after the operation. The recovery of the sensation and the myodynamia was evaluated. The results showed that: the sensation and the motor function innervated by ulnar nerve were recovered. The function of the hand was almost recovered to be normal. It was proved that the end-to-side neurorraphy between the distal stump with the intact median nerve to repair the defect of the ulnar nerve was a new operative procedure for nerve repair. Clinically it had good effect with little operative difficulty. This would give a bright prospect to repair of peripheral nerve defect in the future.

Adult↗
PubMed1997

[Clinical application of implantation of vascular bundle into silicone tube to bridge the peripheral nerve defect].

In order to improve the therapeutic effect of non-neural tissue in bridging the peripheral nerve defect and increase the blood supply of the implant, the silicone tube was chosen to bridge the gap, and the vessel bundle was inserted into the tube. The procedures were performed as following: resected the pseudoneuroma and enveloped the proximal and the distal ends in a silicone tube, and then sutured the epineurium and the tube wall with 7/0 stitch. In patients, eleven cases with fifteen nerves were treated, including seven median nerves, five ulnar nerves and three radial nerves. The lengths of the nerve defects were within 3 cm in 13 nerves and 3 cm-5 cm in 2 nerves. They were followed up from one to five years and the result was excellent (M4S4) in 8 nerves, good (M3S3) in 3 and poor (M1S1) in 2. It was discussed that the indication for the procedure should be included: the nerve defect could not be sutured directly, and the patient would not agree to use his own nerve for graft.

Adolescent↗
PubMed1996

Structurally related Spc1p and Spc2p of yeast signal peptidase complex are functionally distinct.

Two subunits of the mammalian signal peptidase complex, SPC12 and SPC25, share similar membrane topologies with the majority of each protein oriented toward the cytoplasm. Such similarities may suggest that these proteins perform redundant functions in signal peptidase activity. In the present study, we addressed this issue through analysis of the yeast homologs to SPC12 and SPC25, Spc1p and Spc2p. We show that both Spc1p and Spc2p are nonessential for signal peptidase activity and growth of yeast cells and that null mutations in the genes encoding Spc1p and Spc2p are synthetically lethal with a conditional mutation affecting Sec11p, an essential subunit of yeast signal peptidase. However, a high copy plasmid encoding Spc1p suppresses the conditional sec11 mutation, whereas the corresponding plasmid encoding Spc2p does not suppress sec11. Moreover, Spc2p, but not Spc1p, is important for signal peptidase activity and cell viability at high temperatures. These results indicate that although both Spc1p and Spc2p are noncatalytic, they are functionally distinct. Evidence is also presented that a double mutant lacking Spc1p and Spc2p grows well relative to wild type yeast cells, indicating that the signal peptidase complex missing at least two of its subunits is sufficient for signal peptidase activity in vivo.

Amino Acid Sequence↗
PubMed1996

Patterns of distal-less gene expression and inductive interactions in the head of the direct developing frog Eleutherodactylus coqui.

The direct developing frog Eleutherodactylus coqui exhibits radical changes in its embryogenesis. A frog-like head forms directly with no appearance of a cement gland or several jaw cartilages characteristic of tadpoles, and limbs appear early in development. The numerous differences in the embryogenesis of E. coqui provide an opportunity to examine developmental causes for the evolutionary shift from biphasic to direct development. We have cloned DNA fragments corresponding to four E. coqui genes related to the Drosophila distal-less gene Dll. While the expression patterns of the distal-less genes are generally conserved, there are some spatiotemporal differences when embryos of E. coqui are compared to those of Xenopus laevis. The changes in gene expression are correlated with the embryonic changes in head structures including craniofacial cartilages and in particular, the cement gland. We have then examined inductive interactions involved in cement gland formation by interspecific transplants and recombinants. E. coqui embryos can generate signaling that culminates in cement gland formation, but E. coqui ectoderm appears to be incapable of a cement gland response. These results show here that inductive interactions in the anterior region of the E. coqui embryo have been modified during the evolution of direct development, and that changes in the competence of the E. coqui ectoderm may be responsible for the loss of certain tadpole-specific structures, such as cement gland.

Amino Acid Sequence↗