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H Ha

Publications and source records attributed to H Ha.

14 recordsLinked to original sources
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↗
PubMed1989

Difficult tracheal extubation.

We describe a case of nasotracheal tube fixation with a screw. A second case is described in which a broken drill bit was found to impinge on the wall but not penetrate into the lumen of a nasotracheal tube. Possible sequelae of this complication include airway leak, aspiration, tube obstruction, and trauma from attempts at forceful extubation. We recommend the routine intraoperative testing for tracheal tube movement and routine fibreoptic bronchoscopy through the tube when blind surgical procedures occur in the vicinity of a tracheal tube.

Adolescent↗
PubMed1987

Limited capacity for renal vasodilatation in anesthetized diabetic rats.

Studies were conducted to determine whether reduced renal blood flow (RBF) exhibited by rats with uncontrolled streptozotocin (STZ)-induced diabetes is attributable to diabetes-induced structural changes in the renal vasculature. Vehicle-treated control rats (CR) and rats that were injected with STZ (STZR) after pretreatment with 3-O-methylglucose (3-OMG), an agent that prevents STZ-induced hyperglycemia, were also studied. Basal values of total RBF (ml.min-1.g kidney wt-1, electromagnetic flow probe), systemic arterial pressure (BP, mmHg), and renal vascular resistance (RVR, BP/RBF) in pentobarbital-anesthetized rats during a control period were 5.4 +/- 0.3 (P less than 0.01 vs. CR), 116 +/- 3, and 21.9 +/- 1.0 (P less than 0.01 vs. CR) in STZR (n = 12) and 8.2 +/- 0.4, 121 +/- 2, and 15.3 +/- 1.0 in CR (n = 11), respectively. Basal values of RBF, BP, and RVR in 3-OMG-pretreated STZR were identical to CR. The relative capacity of STZR and CR kidneys for vasodilatation in situ in response to intrarenal arterial infusions of acetylcholine (ACh) and bradykinin (BK) and systemically administered sodium nitroprusside (NP) was evaluated. The capacity of STZR to exhibit active renal vasodilatation in response to intrarenal arterial ACh and BK was significantly less than that of CR (P less than 0.01). The minimum level to which RVR was suppressed after 50 micrograms NP/kg iv was higher in STZR than in either CR or 3-OMG-pretreated STZR (14.8 +/- 1.5 vs. 9.0 +/- 0.7 and 9.3 +/- 1.5 mmHg.ml-1.min.g kidney wt, respectively; P less than 0.05). This dose of NP exerted effective functional antagonism of renal vasoconstriction induced by exogenous norepinephrine and angiotensin II. These in vivo studies suggest that the elevated RVR in STZR might be attributable in part to structural changes in the renal vasculature that are associated with the diabetic state and limit the capacity for renal vasodilatation. However, there was no difference in pressure-flow relationships between the two groups in maximally dilated isolated kidneys perfused with Krebs buffer containing 5% albumin, and the RBF deficit in STZR kidneys was corrected by perfusion with blood from CR. Thus the decreased RBF exhibited by STRZ in vivo cannot be attributed solely to renal vascular structural changes associated with diabetes. These findings suggest that undefined humoral factors or abnormal interaction of formed blood elements with vessel walls may account for elevated RVR in STZR.

3-O-Methylglucose↗
PubMed1975

The role of the medial lemniscal and spinocervicothalamic pathways on tactile reactions in cats.

The role of dorsal column (DC)-medial lemniscus and spinocervicothalamic systems on tactile reactions, placing and tactile localization (turning to localize a point touched on the body) was studied in cats with spinal and bulbar lesions. The cats with vision occluded were trained preoperately on horizontal bars for tactile localization. The bulbar lesions of cervicothalamic tract (CTT), which anatomically overlaps with gracile nuclear efferent projection, resulted in permanent loss of tactile placing and localization in contralateral hindlimb. Section of dorsal half of lateral funiculus at C3, which interrupts afferents to lateral cervical nucleus but also involves descending motor pathways, gave loss of tactile placing without impairment of tactile localization. However, combined lesions of both systems abolished tactile placing and localization permanently. Results suggest that tactile placing and localization persists after CTT lesion alone; temporarily loss after DC section but permanently abolished after destruction of both systems. It. is also noted that cats after lesions of both systems without involving motor pathways could walk on bars without vision. The deficits following combined lesions are suggested to be primarily sensory in nature.

Animals↗