Search PubMed⌕ Search

Biomedical subjects

H C Yang

Publications and source records attributed to H C Yang.

At least 73 records · Page 4Linked to original sources
PubMed1993

Planned replacement of daily wear Acuvue disposable contact lenses.

A study of Acuvue disposable contact lenses was performed on 30 patients. The lenses were worn daily and renewed every 2 weeks for 6 months. During collection of these patients, another 16 were excluded due to an improper lens fit. Of the 30 patients included in the study, 98 to 100% had good vision and felt comfortable when wearing Acuvue lens during the whole study course. Twelve (40%) patients felt the lens were floppy and had some difficulty handling them at first. Nineteen (2.4%) of the 780 lenses used had prominent defect and 4 (0.5%) were lost during daily manipulation or wearing. Four (6.6%) eyes suffered mild punctate superficial keratitis. So, patients should be selected carefully because Acuvue lens only have one size and base curve. Acuvue lens can provide good vision and comfort of lens wearing but handling may be difficult at first. Caution should be exercised in checking and manipulating lens to prevent lens and ocular damage.

Adolescent↗
PubMed1993

Protein kinase C activation facilitates memory retention in rats.

We have previously found that intra-hippocampal injection of H7, a protein kinase inhibitor, impairs memory retention in rats in a one-way passive avoidance learning task. It also decreases the optical density of several hippocampal protein bands on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The present study examined whether protein kinase C (PKC) and phosphorylation of its substrate protein are involved in the memory process. The same behavioral paradigm was used. The infusion volume was 0.8 microliter each side throughout all experiments. We have microinjected phorbol ester (TPA), a specific PKC activator, into the dentate gyrus (DG) of hippocampus immediately after training. Animals were subject to the retention test 24 hr after training. Results revealed that TPA enhanced retention performance and protein phosphorylation in rats in a dose-response fashion with doses at 0.8 and 2.0 ng reaching a significant behavioral effect. The high dose of TPA also increased phosphorylation of four protein bands in the cytoplasma with molecular weight (MW) around 48 kDa, 60 kDa, 78 kDa and 116 kDa, respectively; and seven protein bands in the membrane with MW around 38 kDa, 43 kDa, 48 kDa, 80 kDa, 88 kDa, 130 kDa and 210 kDa, respectively. In different animals, we have microinjected staurosporine, a specific PKC inhibitor, into the DG of hippocampus. Results indicated that at the low dose (0.5 ng), staurosporine was without a significant effect. At the middle and high doses (2.0 and 8.0 ng), it markedly impaired retention performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗
PubMed1992

Laparotomy for fulminant pseudomembranous colitis.

Clostridium difficile-associated pseudomembranous colitis is an increasingly common nosocomial infection that usually responds to oral antibiotics. Presentation as an acute abdomen occurred in 12 patients, leading to 14 laparotomies. A distinctive clinical picture was observed: advanced age, recent treatment with antibiotics, fever, abdominal pain, tenderness, marked leukocytosis, and ileus. Only six of the 12 patients had diarrhea. Five were immunosuppressed. Abdominal computed tomographic scans revealed ascites and a massively thickened colonic wall. All four patients treated by subtotal colectomy survived. Four of 10 patients treated only with laparotomy or segmental colectomy died, four responded to medical therapy, and the conditions of two deteriorated but were salvaged by subtotal colectomy. Early diagnosis via endoscopy or computed tomography should obviate the need for exploratory operations. However, progressive toxic effects indicate failure of medical therapy and the need for subtotal colectomy.

Abdomen, Acute↗
PubMed1992

Histologic resolution of documented hemosiderosis in a renal transplant recipient. A case report.

A 33-year-old cadaveric renal transplant recipient showed complete histologic resolution of hemosiderosis by liver biopsies obtained pre- and post-transplantation. Although there have been reports in the past of progression of hemosiderosis to hemochromatosis to severe liver failure in the renal transplant population, the correlation has never been clear. This is the first case report of complete resolution of hemosiderosis as documented histologically by liver biopsies in a cadaveric renal transplant recipient.

Adult↗
PubMed1992

In vivo effects of doxorubicin on kinase C in cultured cells.

The ability of doxorubicin to inhibit kinase C in vivo in cultured BALB/c 3T3 mouse fibroblasts was determined by the phosphorylation of the myristoylated alanine-rich C kinase substrate (MARCKS) and the induction of c-fos transcription following treatment with 200 nM phorbol 12-myristate 13-acetate. A concentration of 60 microM doxorubicin did not inhibit MARCKS phosphorylation but completely inhibited c-fos expression. The inhibition of c-fos expression was not specifically mediated via kinase C, since both the total RNA synthesis as measured by [3H]-uridine uptake and the fraction of serum-induced c-fos expression that was not attributable to kinase C were inhibited by doxorubicin. The present data do not support the hypothesis that the cytotoxic effect of doxorubicin is attributable to the inhibition of kinase C in vivo.

3T3 Cells↗
PubMed1992

Spontaneous pulsatile growth hormone release in male and female premature infants.

Although premature infants have high umbilical cord GH levels, little is known about spontaneous GH release in these individuals. The purpose of our study was to investigate spontaneous 12-h GH release in appropriate for gestational age male and female premature infants. We studied 22 premature infants (15 males and 7 females) of appropriate length and weight for age. Gestational ages, birth weights, birth lengths, and ages at the time of study were similar in male or female infants. All infants were biochemically euthyroid. Blood was taken every 30 min over a 12-h period from an indwelling umbilical catheter; no stress occurred during the blood withdrawal. GH was determined by a double antibody RIA, using 0.01 mL plasma. GH pulse detection was undertaken using Cluster, a computerized pulse detection algorithm. Total insulin-like growth factor-I and -II (IGF-I and -II) levels were measured after separation of the IGFs from the serum binding proteins. Spontaneous pulsatile GH release was observed in all infants studied. No differences were found between males and females in the pulse characteristics of frequency, maximal amplitude, incremental amplitude, width, or area. The GH pulse frequency per 12 h was 3.2 +/- 0.3 (mean +/- SE) in males and 3.0 +/- 0.7 in females. The maximal pulse amplitude was 50.7 +/- 6.2 micrograms/L in males and 44.7 +/- 9.0 micrograms/L in females. The incremental pulse amplitude was 24.3 +/- 3.2 micrograms/L in males and 20.2 +/- 3.9 micrograms/L in females. The mean 12-h GH level was 37.1 +/- 4.8 micrograms/L in males and 35.8 +/- 8.5 micrograms/L in females; the average GH nadir was 26.1 +/- 4.0 micrograms/L in males and 24.4 +/- 8.3 micrograms/L in females. Both IGF-I and IGF-II concentrations were similar in males and females. The mean IGF-I levels were 10.7 +/- 1.5 ng/mL in males and 7.5 +/- 1.1 ng/mL in females; IGF-II levels were 96.0 +/- 12.0 ng/mL in males and 115.4 +/- 17.1 ng/mL in females. These results demonstrate similar pulsatile GH release in male and female premature infants at a mean age of 32-33 weeks. Compared with previously reported values for mean GH concentration and average GH nadir in older children, the values in these premature infants were much higher. We speculate that the higher GH levels in premature infants may result from decreased negative feedback associated with low IGF-I levels. The premature infant's somatotrophs may also not fully respond to the GH inhibitory action of somatostatin.

Blood Glucose↗
PubMed1992

Extracorporeal shock wave lithotripsy in the renal transplant patient: a case report and review of literature.

Renal allograft lithiasis is a rare complication of renal transplantation, which in the past has required various invasive procedures for adequate stone fragmentation and dissolution. Noninvasive techniques such as extracorporeal shock wave lithotripsy (ESWL) can now be extended to the renal transplant patient. Five cases have been previously reported in which ESWL was used effectively for dissolution of renal allograft calculi. We now report a 6th case in which a calculus, initially identified 2 weeks after renal transplantation, was effectively fragmented 3 years later using ESWL. Based on our experience and the reviewed composite experience in the literature, ESWL is a safe therapy for renal allograft calculi.

Adult↗
PubMed1992

[Monitoring of renal function in burn patients with radioimmunological evaluation].

Urinary beta 2-microglobulin, albumin, IgG, Tamm-Horsfall mucoprotein, and glycoprotein were determined on PBD 0, 1, 3, 7, 14, 21, 27. It was found that the amount of albumin was double that of normal in patients with burn extent of 30%-50% TBSA, while IgG showed no change. In patients with over 50% TBSA burns, Alb was five-fold and IgG four-fold of normal. They probably indicated the degree of damage to the glomeruli. In 27 patients with infection, beta 2-m was increased, indicating damage to the proximal convoluted tubules. Glycoprotein showed a tendency to increase in moderate and severe burns, while it was markedly reduced in very large burns or renal failure, indicating damage to the ascending limb of thick medullary loop. The changes in the amount of urinary protein were more sensitive in reflecting early functional changes of the kidney.

Adolescent↗
PubMed1992

[Biologic effects of Tween 80 in combination with hyperthermia on human stomach cancer cell line BGC-823].

Cells of human stomach cancer cell line BGC-823 were treated with Tween 80 and hyperthermia 39 degrees C to 43 degrees C for 20 to 100 minutes. Normal human fibroblasts and mitomycin C were used as controls. The results showed Tween 80 greatly reduced the activation energy of BGC-823 cells. Synergistic effect was observed if applied with heat 39 degrees C. With the increase in temperature and time, the inhibitory effect on the cancer cells was gradually intensified. The lethal rate of heat 41 degrees C associated with Tween 80 was 5.2 times as that of heat alone. The inhibitory effect of heat 41 degrees C for 100 minutes combined with Tween 80 was equivalent to 43 degrees C for 100 minutes. In other words, the heat critical Temperature of BGC-823 cells was reduced about 2 degrees C. The measurement of membrane fluidity, SDH activity and the rest also showed heat 41 degrees C produced the highest synergy with Tween 80. The specific and sustained action exceeded that of mitomycin C. The response of the normal cells was mild and reversible. These studies suggest that the synergistic mechanism of Tween 80 and hyperthermia possibly lies on the cell plasma membrane system.

Humans↗
PubMed1991

Decreased expression of the myristoylated alanine-rich C kinase substrate in transformed BALB/C 3T3 mouse fibroblasts.

Expression of the myristoylated alanine-rich C kinase substrate was studied in the untransformed A31 and the transformed BPA31, DA31 and KA31 BALB/c 3T3 mouse fibroblast cell lines. The MARCKS transcript was markedly reduced in the three transformed cell lines. Southern analysis revealed similar gene copy number and no apparent DNA rearrangement. In the untransformed A31 cells, the MARCKS mRNA was constitutive in the cell cycle.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1991

Arterial reconstruction of the pancreatic allograft for transplantation.

The shortage of organs is particularly acute in whole pancreas transplantation, because the liver and pancreas often share a common arterial supply, making combined procurement of both organs difficult. A previously described technique of simultaneous whole liver and pancreas procurement depended on "classic" hepatic arterial anatomy, which is present just over half the time. We describe herein our experience with three Y-reconstructions of the splenic and superior mesenteric arteries of the pancreatic allograft using donor allograft internal and external iliac arteries. In situ Doppler ultrasound examination of the pancreatic allograft after surgery demonstrated a patent reconstruction without evidence of stenosis or turbulent flow patterns. We believe this reconstruction is a safe, alternative method to provide arterial flow to the whole donor pancreas.

Humans↗
PubMed1991

Regulation of the retinoblastoma anti-oncogene in aging human diploid fibroblasts.

Cell cycle expression of the retinoblastoma (RB) gene was investigated in young and aging IMR 90 human diploid fibroblasts and in the immortalized but untransformed A31 BALB/c 3T3 mouse fibroblasts. RB RNA levels increased about 75% during late G1/S in both the young and old IMR 90 cells. Young and old cells had similar normalized amounts of RB RNA per cell. Kinase C activation did not stimulate RB transcription. The A31 cells showed a constant RB RNA level throughout G0/S. The data is consistent with the hypothesis that RB activity is regulated primarily post-transcriptionally and indicates that a change in the regulation of RB transcription is not part of the senescence phenomenon.

Animals↗
PubMed1990

Selective binding of plasmin in the presence of excess plasminogen by certain anionic polystyrene resins.

Contact of plasminogen with sulfonate or sulfonyl-glutamate derivatized polystyrene resins has previously been reported to lead to the formation of an active single-chain form of the plasminogen (Kichenin-Martin et al., Thrombosis Research, 52, 469-478, 1988). Attempts to duplicate this finding revealed instead that these polymers selectively adsorb active plasmin and thus remove it even in the presence of a great excess of plasminogen. Under optimum conditions 4.0 mg/mL plasminogen containing 3% plasmin was freed of one half of this contaminant by exposure to 6-9 mg of dry resin per mL in a batch mode. Neither ordinary polystyrene nor Dowex nor Sephadex cation exchange resins displayed these properties. The separation is based on the more rapid binding of plasmin to the active resins and is thus kinetically controlled.

Anions↗
PubMed1990

Early kinase C dependent events in aging human diploid fibroblasts.

Two early kinase C dependent events, the induction of c-fos transcription and the phosphorylation of an 87 kDa protein, were investigated in aging IMR 90 human diploid fibroblasts. C-fos induction and 87-kDa protein phosphorylation were similarly regulated in aging cells and their young counterparts. The data suggests that G0 exit or the competence phenomenon is intact in aging cells and that the proliferative block occurs later in G0/S.

Aging↗