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Biomedical subjects

H Ha

Publications and source records attributed to H Ha.

At least 73 records · Page 4Linked to original sources
PubMed1996

Interleukin 4-induced proliferation in normal human keratinocytes is associated with c-myc gene expression and inhibited by genistein.

We studied the effect of IL-4 on the proliferation of cultured normal human keratinocytes. Keratinocyte proliferation was stimulated by IL-4 and inhibited by anti-IL-4 antibody in a concentration-dependent manner. Anti-IL-6 antibody did not inhibit normal human keratinocyte proliferation, suggesting that the IL-4 could directly induce proliferation of these cells. IL-4 significantly induced cell cycle G0/G1 to S phase progression. The keratinocyte proliferation by IL-4 was mediated through one of the growth control genes, c-myc protooncogene. The expression of c-myc mRNA was significantly increased after IL-4 treatment of the keratinocytes, suggesting that c-myc plays a key role in the control of proliferation. The signal transduction pathways induced by IL-4 in the keratinocytes were studied with inhibitors of signal transduction. Genistein, a tyrosine kinase inhibitor, suppressed the level of the induced c-myc mRNA expression, but H7, a serine/threonine kinase inhibitor, and okadaic acid, a protein phosphatase 1 and 2A inhibitor, did not block the induced c-myc gene expression. Taken together, these results suggest that IL-4 stimulates the proliferation of keratinocytes in vitro by promoting a transition from G0/G1 to S phase of the cell cycle. Induction of c-myc after IL-4 treatment could indicate an important role for c-myc in the proliferation of keratinocytes. Our observations also suggest that tyrosine kinases may be involved in IL-4-induced proliferation.

Base Sequence↗
PubMed1996

Role of tumor necrosis factor-alpha on mesangial cell MCP-1 expression and monocyte migration: mechanisms mediated by signal transduction.

Monocyte chemotactic protein-1 (MCP-1), a specific chemoattractant for monocytes, has been thought to play an important role in the recruitment and accumulation of monocytes within the glomerulus seen in glomerular diseases. This study examined the role of tumor necrosis factor (TNF)-alpha-mediated cellular signal transduction pathways on mesangial cell MCP-1 gene expression and monocyte migration. Incubation of mesangial cells with TNF-alpha stimulated MCP-1 mRNA expression in a dose- and time-dependent manner. Phorbol myristate acetate (PMA), a protein kinase C (PKC) activator, increased MCP-1 message by mesangial cells while depleting PKC decreased MCP-1 gene expression to control levels. Activation of PKC-depleted mesangial cells with PMA but not with TNF-alpha inhibited MCP-1 mRNA expression. Similarly, calphostin C, a PKC inhibitor, failed to inhibit TNF-alpha-induced MCP-1 expression. The incubation of mesangial cells with various protein tyrosine kinase inhibitors (PTK, e.g., herbimycin, tyrphostin, genistein) blocked TNF-alpha-induced MCP-1 mRNA message. Additional experiments examining the role of cAMP on MCP-1 expression indicated that the preincubation of mesangial cells with various cAMP generating substances (pertussis toxin, isoproterenol, dbcAMP) did not induce mesangial cell MCP-1 mRNA transcripts. However, the coincubation of mesangial cells with TNF-alpha and dbcAMP completely inhibited TNF-alpha-induced MCP-1 gene expression. Finally, TNF-alpha-activated mesangial cell media increased monocyte transmigration that could be blocked by neutralizing anti-MCP-1. These studies indicate that TNF-alpha facilitates monocyte transmigration into the glomerulus mediated by the increased expression of MCP-1 by mesangial cells. TNF-alpha-induced mesangial cell MCP-1 expression is regulated by signal transduction pathways involving PTK but not those dependent on PKC or cAMP.

Animals↗
PubMed1996

[Medicine in Taiwan during the period of Japanese occupation].

During this period, malaria, pneumonia, dysentery and enteritis, and acute infectious diseases, including plague, typhoid fever, dysentery, cholera, smallpox, infectious epidemic meningitis, malaria, tsutsugamushi and endemic diseases such as goitre were the important causes of death. In parasitology, the most important discovery was lung fluke, followed by research achievement in clinical and basic sciences. In Taiwan, studies on poisonous snake were proceeded rather early. The special medical system in this period included the Gynecological Hospital and medical insurance system. In the medical staff, not a few Japanese were included. Dr. Du Congming, who made great contributions to medicine in Taiwan, may be viewed as the father of medicine in Taiwan. A Journal of Taiwan Medical Association was published in Taiwan by the said Association.

History, 20th Century↗
PubMed1995

Identification of polymorphisms in the constant region of IgG3: the missing mouse allotype.

We have identified DNA sequence polymorphisms in the C gamma 3 genes of BALB/c and C57BL/6 mice. One of these results in a Ser-->Gly amino acid difference in CH1 at position 129 according to the Wu and Kabat numbering system. There are three additional silent substitutions in the coding region and two polymorphic nucleotides in the 3' untranslated region. According to standard nomenclature in which alleles are numbered according to the order of their identification, these C gamma 3 alleles are designated Igh-8a and Igh-8b respectively. We also describe two polymerase chain reaction-based assays that identify the allelic differences.

Alleles↗
PubMed1995

Applications of MTT assay to primary cultured rat hepatocytes.

We investigated the optimal conditions for the application of the MTT assay to determine the viability of cell in primary cultures of rat hepatocytes. The optimal conditions were found to be: inoculation at cell density of 1.31 x 10(5) cells/cm2; concentration of 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) 0.12 mM; and MTT incorporation time, 2 h or more. We also found that insulin and glucocorticoid, which are usually added to the medium to maintain cell function, had no effect on the viability of the primary cultures of rat hepatocytes.

Animals↗
PubMed1995

[Early missionary medicine in Taiwan].

Taiwan, as mainland China, first received modern medicine from Christian missionaries. Although Western medicine was introduced by the Dutch in the 17th century, it disappeared after their expulsion by Zheng Chenggong. It was not until 1865 when the British Presbyterian Church sent Dr. James Laidlow Maxwell to Taiwan to engage in medical and missionary work that Western medicine was able to take root in Taiwan. The last three decades of the 19th century were a key period in the development of modern medicine in Taiwan. This paper discusses three major figures in early missionary medicine in Taiwan, Dr. James Laidlow Maxwell, Rev. George Leslie Mackay, and Dr. David Landsborough and their contributions to the development of modern medicine in Taiwan.

History, 19th Century↗
PubMed1995

[Medicine in Taiwan during the period of Japanese occupation].

During the period of 1894-1945, hygienic administration institutions were established in the central and local levels, responsible for general hygienic affairs, including prevention of infectious diseases, public health, anti-opium smoking and drug inspection. Medical education and research unit were also set up, such as Taibei Hospital, Taiwan Viceroy Medical School and Taibei Imperial University. From these institutions, not a few medical professionals were cultivated.

Colonialism↗
PubMed1994

Structure, chromosomal localization, and methylation pattern of the human mb-1 gene.

The Ag receptor on B lymphocytes is a multimeric complex that is composed of an Ag-specific component, surface Ig, which is noncovalently associated with at least two other proteins, Ig alpha and Ig beta. These are the glycoprotein products of the B lineage-restricted mb-1 and B29 genes and are crucial for the cell surface expression and function of the Ag receptor on B lymphocytes. To better understand the regulation of mb-1, we have cloned and sequenced a 5.7-kb genomic DNA fragment that contained the human gene. The overall structure of human mb-1 is very similar to that of the murine gene, including the number and approximate size of exons. The promoter region lacks a TATA element, but contains two copies of an early B cell factor-binding motif, which previously has been shown to be important for murine mb-1 expression. Other structural features include two nuclear factor-kappa B binding sites at the 5' end of the gene and a long stretch of AG rich-sequence between exons 3 and 4, downstream of an Alu repeat sequence that contains a potential stem-loop structure. The mb-1 gene was localized to chromosome 19q13.2-13.3 by a combination of two methods, PCR amplification of DNA from a somatic cell hybrid-mapping panel and fluorescence in situ hybridization. An examination of the methylation pattern revealed a striking correlation between demethylation in the 5' region of the gene and expression of mb-1. The demethylated HpaII/MspI sites are adjacent to the nuclear factor-kappa B-binding motifs, which suggests a role for this transcription factor in the regulation of human mb-1 gene expression.

Amino Acid Sequence↗
PubMed1994

DNA damage in the kidneys of diabetic rats exhibiting microalbuminuria.

8-Hydroxydeoxyguanosine (8-OHdG), an oxygen radical induced modification of purine residue in DNA, was measured in the liver, pancreas, and kidney of streptozotocin-induced diabetic rats (STZR) exhibiting microalbuminuria. At 4 weeks after the injection of streptozotocin (50 mg/kg, i.v.), the rate of urinary albumin excretion was 0.5 +/- 0.1 and 2.0 +/- 0.2 mg/24 h in age-matched control rats (CR) and STZR, respectively. Compared to CR, STZR also showed a significantly increased level of 8-OHdG in the kidney but not the liver and pancreas. Amounts of 8-OHdG/10(5) dG for CR and STZR were 3.4 +/- 0.3 and 5.1 +/- 0.2 for renal cortices, and 4.1 +/- 0.2 and 20.0 +/- 3.7 for renal papillae. Daily injection of insulin (2 U, SC) starting on the third day after streptozotocin treatment significantly reduced both urinary albumin excretion and papillary 8-OHdG formation, which suggests that these are associated with the diabetic state induced by streptozotocin rather than a direct nephrotoxic effect of the drug. This study suggests that formation of 8-OHdG and, therefore, oxidative damage are closely related in the process of diabetic nephropathy.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1994

High glucose can induce lipid peroxidation in the isolated rat glomeruli.

The present study examined the effect of elevated glucose on glomerular cell membrane lipid peroxidation. Glomeruli were isolated from male Sprague-Dawley rat kidneys utilizing a standard sieving method and incubated in medium containing different concentrations of glucose at 37 degrees C for one and 48 hours. The levels of lipid peroxides (LPO) in the glomeruli were quantitated by malondialdehyde-thiobarbituric acid adduct formation. The levels of LPO in the glomeruli were significantly increased after one hour of exposure to high glucose (HG; 30 mM) medium, and this increase was sustained after 48 hours of exposure to HG. In contrast, osmotic control media containing either L-glucose or mannitol did not increase glomerular LPO. Dimethylthiourea (20 mM), a hydroxyl radical scavenger, completely blocked the increase of LPO in the glomeruli exposed to HG not only for one hour but also for 48 hours without altering LPO levels in the glomeruli exposed to control glucose. This provides evidence that oxidative stress can be induced by high ambient concentrations of glucose. Pretreatment with PKC antagonists, either 500 microM H-7 or 100 nM staurosporine, prevented the increase of LPO in the glomeruli exposed to HG for one hour but not in glomeruli exposed for 48 hours. These data suggest that (i) elevated glucose levels per se can cause oxidative stress and augment membrane lipid peroxidation of glomeruli, and (ii) activation of PKC may play a role in early phase of glucose-induced glomerular lipid peroxidation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1994

[Study on healing art among the aboriginals of Taiwan].

The aboriginals of Taiwan who settled the island prior to the Han nationally can be divided into two groups, sinified plain people and less sinified mountain dwellers. The mountain dwellers fall into different groups; the Atayal, Saisiat, Bunun, Tsou, Rukai, Paiwan, Puyuma, Ami, and Yami. Before modern medicine penetrated the lives of the aboriginal, disease was treated by sorcery or by empirically applied herbal medicines. We visited various townships in Taiwan, including Chenggong, Daren, Haiduan, Puyuma, Changbin, and Yanping of Taidong County, Taidong City, and the offshore island of Lanyu; Mudan, Pindong County; and Fuxing, Taoyiuan County. We thereby covered the Ami, Paiwan,, Bunun, Puyuma, Yami, and Atayal groups. Although the aboriginals of Taiwan belong to the Malayo-Poly-nesian cultural system, there are nevertheless major differences among them. The aboriginals of Taiwan believe disease to be a punishment of the gods or the malicious interference of evil spirits. The various groups have distinct shamanistic rituals. This paper discusses the practices of sorcery in the Paiway, bunun, and describes the herbal remedies used by them.

History, Ancient↗
PubMed1994

[Medicine in Taiwan, during the period of Dutch occupation].

During the 38 years of Dutch occupation, by dispatching doctors from the East Indie Company to Taiwan, working at the trading institution for clinical purpose, the Dutchman achieved its missionary and ruling aims. This paper analyses the causes of the Dutch not being able to root on Taiwan. Comparison is made on the medicines between the periods of Dutch occupation and the period of Japanese closed-door policy.

Commerce↗
PubMed1993

A mitochondrial porin cDNA predicts the existence of multiple human porins.

Pores formed in the outer membrane of mitochondria by mitochondrial porin make it permeable to water-soluble metabolites smaller than approximately 5 kDa. We have isolated a full-length cDNA encoding a human porin. This probe detects a single approximately 1.5-kilobase mRNA species on Northern blots, but multiple hybridizing bands on genomic Southern blots. The open reading frame predicts a 38.1-kDa protein with a pI of 6.59 that is homologous but not identical to a previously reported protein sequence of a 31-kDa porin isolated from human lymphocytes (porin 31HL). The most striking difference between the two porins is that the sequence predicted by the cDNA is longer than the 31HL porin by 27 amino acids at the amino terminus and 38 amino acids at the carboxyl terminus. The porin cDNA directs the in vitro translation of two protein species of approximately 32 and approximately 36 kDa, which appear to result from alternate usage of AUG initiation codons. The 32-kDa protein is the predominant species imported into both rat and yeast mitochondria in vitro. Taken together, these results suggest that multiple porin proteins can be expressed in humans. Additionally, a porin consensus protein sequence has been identified that is conserved in eukaryotic organisms as diverse as yeast and man.

Amino Acid Sequence↗
PubMed1992

Lipid peroxidation in isolated rat nephron segments.

Elevated levels of lipid peroxides (LPO) in tissues have been considered an index of increased reactive oxygen metabolites, which are important pathological mediators also found in the kidney. By adopting the quantification of malondialdehyde-thiobarbituric acid adduct as a standard, using a fluorometer, a microassay was developed that enabled us to measure LPO in tissue having less than 1 microgram protein. By this method, basal levels of LPO along the rat nephron showed that proximal tubules bear more LPO per millimeter of tubule than distally located segments (approximately 0.2 pmol/mm tubule for proximal tubules and 0.02 for thick ascending limbs) and that S3 was the highest LPO per tissue protein (2.2 +/- 0.1 pmol/microgram protein, n = 8). In addition, the levels of LPO were stimulated by 10 microM phorbol 12-myristate 13-acetate (PMA) in both glomeruli and S3 (P less than 0.001) and in S2 (P less than 0.05). Furthermore, sphingosine (100 microM), a protein kinase C (PKC) inhibitor, totally blocked the LPO increment by PMA without any effect on the basal LPO in glomeruli, suggesting the involvement of PKC in LPO formation. Taken together, the results indicate the applicability of LPO assay to the nephron for evaluation of site-specific nephrotoxic insult and its mechanisms in renal pathophysiology.

Animals↗
PubMed1992

Amelioration of diabetic microalbuminuria and lipid peroxidation by captopril.

Administration of captopril, a scavenger of oxygen derived radicals as well as an inhibitor of angiotensin converting enzyme, has been an efficient way of treating diabetic proteinuria. In the present study, we evaluate whether captopril can ameliorate diabetic proteinuria as an effect on oxidative stress in streptozotocin- induced diabetic rats (STZR). At four weeks after the injection of streptozotocin (50 mg/kg, i.v.), STZR (n = 5) exhibited microalbuminuria. The rate of urinary albumin excretion was 0.5 +/- 0.1 and 2.6 +/- 0.3 mg/24hr in age-matched control rats (CR; n = 5) and STZR, respectively. Compared to CR, STZR also showed an extremely increased rate of urinary lipid peroxides (LPO) excretion, an index of oxygen derived radicals generation. The respective values for CR and STZR were 0.6 +/- 0.3 and 6.9 +/- 0.6 mumol/24 hr. Significant amelioration of urinary albumin and LPO excretion rate by the treatment of insulin (2 U/day) suggests that these are associated with the diabetic state induced by streptozotocin rather than a direct effect of streptozotocin. Chronic administration of captopril, which did not cause any discernible effect on CR, significantly reduced the urinary albumin excretion rate and decreased LPO excretion in STZR. The urinary albumin excretion rate was significantly correlated with the LPO excretion rate (p = 0.0004). These results suggest that oxidative stress can be responsible for diabetic microalbuminuria, and captopril could diminish the lipid peroxidation and ameliorate the microalbuminuria in diabetic rats.

Albuminuria↗
PubMed1991

Primary structure of the embryo-expressed gene KE2 from the mouse H-2K region.

Nucleotide (nt) sequence of the KE2 wild-type (wt) cDNA revealed a novel 669-bp open reading frame encoding a putative hydrophilic protein of 127 amino acids, pI 6.17. Comparison of the wt to the genomic nt sequence from the tw5 mutant shows the KE2 gene is conserved and is probably a functional gene unrelated to the tw5 lethality.

Amino Acid Sequence↗
PubMed1991

Several testis-expressed genes in the mouse t-complex have expression differences between wild-type and t-mutant mice.

The t-complex of the mouse occupies the proximal half of chromosome 17 and contains genes which have profound effects on spermatogenesis. Mutations of several loci in the t-complex appear to interact to cause male sterility or transmission ratio distortion (TRD). By cDNA screening or chromosomal walking we have identified seven genes, which are expressed in the germ cells of testis and map to various regions of the t-complex. These genes were named t-complex testis-expressed (Tctex) genes. An analysis of their expression patterns in testes from +/+, +/t, and t/t mice was done by in situ hybridization and by northern blotting. Six genes begin to be expressed at the pachytene stage: Three of them are more abundant at pachytene stage, while three others are more abundant at postmeiotic stages. One gene is expressed at all the stages of spermatogenesis. Interestingly, four Tctex genes show differences in the amount of transcript between wild-type and t-mutant testes. The chromosomal location and expression pattern imply that Tctex genes might be candidate genes for sterility or TRD.

Animals↗