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Biomedical subjects

T Y Lin

Publications and source records attributed to T Y Lin.

At least 181 records · Page 10Linked to original sources
PubMed1988

Effect of Yag-laser anterior capsulotomy on the biochemical content of aqueous humor.

Elevation of prostaglandins and protein in the aqueous humor is an immediate response to Yag-laser anterior capsulotomy. There was a significant correlation between prostaglandins and thromboxane to the elevation of intraocular pressure. The elevation of protein concentration was proportional to the elevation of prostaglandin F1, but not to thromboxane. The biochemical changes in the aqueous humor were more severe as laser power was increased above 3 mj. While the role of prostaglandins in the elevation of intraocular pressure is uncertain, the present data recommend the selection of laser power below 3 mj to avoid pressure rise instead of inhibition of all prostaglandin synthesis by medication.

Aqueous Humor↗
PubMed1987

Crystallization of human neutrophil elastase.

Human neutrophil elastase was inactivated by methoxysuccinyl-L-Ala-L-Ala-L-Pro-L-Ala-chloromethane. The modified enzyme was crystallized from 40 mM ammonium phosphate, pH 7.0 in the hexagonal space group P6(3) with unit cell parameters a = 74.53 A, b = 74.53 A, c = 70.88 A, alpha = beta = 90 degrees, gamma = 120 degrees. These crystals were resistant to radiation damage and diffracted beyond 1.84-A resolution. The asymmetric unit contained one 25,000-dalton monomer of human neutrophil elastase. Crystals were also grown from the enzyme modified with the analogous iodinated inactivator, p-iodoanilinosuccinyl-L-Ala-L-Ala-L-Pro-L-Ala-chloromethane. These crystals proved to be isomorphous with those of methoxysuccinyl-L-Ala-L-Ala-L-Pro-L-Ala-chloromethane-modified human neutrophil elastase, and served as a single-site, heavy atom derivative for solving the tertiary structure of the enzyme.

Crystallization↗
PubMed1987

Pig pancreatic anhydro-elastase. Role of the serine-195 hydroxy group in the binding of inhibitors and substrate.

The binding constants of a number of ligands were measured for pancreatic elastase (PE) and anhydro-elastase (AE) in order to assess the contribution of Ser-195 to substrate and inhibitor binding by PE. AE was purified by affinity chromatography on a column containing immobilized turkey ovomucoid inhibitor. The AE had 0.1 +/- 0.1% of the activity of the native enzyme and contained 0.8 +/- 0.06 residue of dehydroalanine per molecule. A difference electron-density map, derived from an X-ray crystallographic analysis of AE, showed that the modified residue was Ser-195. The complexing of 3-carboxypropionyl-Ala-Ala-Ala-p-nitroanilide (SAN) to the active site of AE was also demonstrated by X-ray-diffraction analysis of an AE crystal soaked overnight with substrate. The nitroanilide moiety was not observed in the difference map. AE was shown to bind turkey ovomucoid inhibitor with a dissociation constant (Kd) of 0.3 +/- 0.06 microM compared with 0.10 microM for PE. The Kd of the AE-SAN complex (0.2 mM) was comparable with the Michaelis constant for SAN with PE (1.0 mM). A number of inhibitors, such as elastatinal, which forms a hemiketal adduct with PE, while others such as the beta-lactams, which function as acylators of the active-site serine residue, bound AE with a lower affinity than to PE. The binding of a peptidylchloromethane (acetyl-Ala-Ala-Pro-Ala-CH2Cl) to AE occurs without evidence for alkylation of histidine. The binding constants for benzoisothiazolinone and 3,4-dichloroisocoumarin to PE differed from their binding constants to AE by less than a factor of 4.0-fold. The contribution of the hydroxy group of Ser-195 to the binding of these inhibitors to PE in their non-covalent complexes is relatively small, even though they inactivate PE by an acylation mechanism. These results suggest that the hydroxy group on Ser-195 in PE is of secondary importance in the energetics of ligand binding, in contrast with its essential role in the catalytic properties of the enzyme.

Binding Sites↗
PubMed1987

Role of surgery in the treatment of primary carcinoma of the liver: a 31-year experience.

During the 31 year period 1954 to 1985, 225 major hepatic resections have been performed for symptomatic primary carcinoma of the liver, of which right hepatic lobectomy was performed in 115, extended right hepatic lobectomy in 11, trisegmentectomy in 2, left hepatic lobectomy in 94, and middle hepatectomy in 3. In addition there were 107 partial hepatic resections for 89 asymptomatic small hepatocellular carcinomas. In the 225 patients undergoing major hepatic resection, the operative mortality was 8.0 per cent. In the 107 patients undergoing partial hepatic resection, the operative mortality was 5.6 per cent. Of the total of 314 hepatic resections for primary carcinoma of the liver, 309 were undertaken for hepatocellular carcinoma and the remaining 5 were carried out for cholangiocarcinoma. All hepatic resections in this series were performed with the finger fracture technique without controlling the hepatic hilar vessels, hepatic ducts or hepatic veins outside the liver, although hepatic clamping and the Pringle manoeuvre were also used in selective cases. Of 207 cases who survived major hepatic resection, 119 cases died within one year after the operation, mainly due to recurrence of cancer in the remaining residual lobe, lung metastasis or late hepatic failure. The 5 year survival rate is 18.0 per cent, 12 patients are still alive and well after more than 5 years and the longest survival is 23 years. Of the 89 patients with small asymptomatic hepatocellular carcinomas, 28 died within one to four years of surgery because of a second new growth.

Adult↗
PubMed1987

A measure of the 'sick' label in psychiatric disorder and physical illness.

Persons with psychotic disorders receive devalued labels. Despite considerable theorizing, the proposition that these labels affect the course of psychotic illness has rarely been subjected to investigation. The lack of an adequate operational measure for the labeling construct has hampered research. The present report describes the development of the Social Response Questionnaire (SRQ), a measure of the 'sick' label which incorporates moralistic attitudes, fear of dangerousness and negative expectations attached to the role of the severely psychiatrically ill. This 32-item scale, a multidimensional measure of informal labeling, which may be administered in a self-report format or to significant others, permits the study of dose-response relationships. The SRQ is internally stable. It also exhibits construct validity. Schizophrenics and persons with affective psychosis label themselves and are labeled by others more harshly than persons with Crohn's disease or normals. While self-percepts and the perceptions of significant others are fairly congruent for normals and persons with a significant physical illness, there is no agreement between the self-ratings of psychotics and their significant others. Psychotic persons view themselves more negatively than Crohn's disease sufferers or normals, but not as negatively as their therapists, families and friends. Potential uses for the SRQ in longitudinal research are addressed.

Adolescent↗
PubMed1987

Two Japanese families: a cultural perspective.

Some of the difficulties in treating second and third generation Japanese immigrant families are reviewed. An authoritarian, rather concrete approach to symptom relief is expected by, and is effective in, some families. The emphasis placed on academic achievement may lead to particular problems and misunderstandings. Two case examples of very different families are presented to emphasize a flexible therapeutic approach. Particular details of Japanese internment and population movements make the attitudes and behaviors of some families more comprehensible.

Acculturation↗
PubMed1987

Factors affecting ascorbate oxidation in aqueous humor.

Aqueous humor from human glaucomatous eyes was divided into two groups. Group I aqueous humor contains a negligible amount of ascorbate, while group II contains ascorbate. Group I aqueous humor stimulates ascorbate oxidation. This oxidative effect is inhibited by the addition of EDTA, indicating the presence of metallic ions. The amount of copper determined by atomic spectrophotometry in these samples was 1.54 micrograms/ml. On the contrary, group II aqueous humor protects against ascorbate oxidation. The small amount of albumin present in these samples accounts for part of this protective effect.

Aqueous Humor↗
PubMed1987

[The study of the controlled ovarian stimulation and sperm capacitated AIH for the treatment of refractory infertility].

The clomiphene or hMG to stimulate ovarian follicle maturation which we call "controlled ovarian stimulation (COS)", in vitro capacitation (IVC) of spermatozoa and artificial insemination of husband's sperm (AIH) were simultaneously given to refractory infertile couples. The following couples were studied in 5 groups, 1 male subfertility 27 cases, 2 functional infertility 25 cases, 3 ovulatory dysfunction due to central mechanism 8 cases, 4 cervical mucous insufficiency 3 cases, 5 endometriosis 6 cases. The pregnancy rate was 21.7% in total (15 of 69 cases): 25.9% in group 1, 16.0% in group 2, 25.0% in group 3, 33.3% in group 4 and 16.7% in group 5. The follicle size and serum estradiol were measured every day during the periovulatory phase to evaluate follicle maturation. The Percoll centrifugation method was compared with the washing-centrifugation method with respect to the recovery rate and the concentration rate of motile spermatozoa. The recovery rate was 67.9% with the Percoll centrifugation method, and 40.0% with the washing-centrifugation method. The concentration rate was 1.81 times in the Percoll centrifugation method, and 1.19 times in the washing-centrifugation method. The present studies indicated that the combination of COS and IVC methods for AIH in refractory infertile couples was very effective.

Clomiphene↗
PubMed1986

Multiculturalism and Canadian psychiatry: opportunities and challenges.

In this lecture, the writer calls the attention of Canadian psychiatrists to the unparalleled opportunities the national policy of multiculturalism has for clinical and research activities. Using illustrations from three important fields in psychiatry--epidemiology, psychopharmacology and psychotherapy, he points out the roles socio-cultural factors play in generating ethnic differences which deserve to be given serious scientific attention for both the understanding of causative factors and the treatment of mental disorders. He emphasizes that medical universalism and ethnocentricism have no place in Canadian psychiatry, and that the next phase of Canadian psychiatry should focus on cultural relevancy based on cultural relativism and equal participation of all cultures and ethnic groups.

Canada↗
PubMed1986

Surgical treatment of 109 patients with symptomatic and asymptomatic hepatocellular carcinoma.

A total of 109 patients with histologically proved hepatocellular carcinoma (HCC) have undergone hepatic resection during the 56-month period from October 1978 to May 1983. There were two sources of patients: those with symptomatic HCC (n = 47) and those with asymptomatic HCC (n = 62). A family tendency of HCC was noted in 11% of the patients studied. The percent of positive hepatitis B surface antigen (HBsAg) was 87%, and the serum alpha-fetoprotein was less than 20 ng/ml in 30% in the group with symptoms. The operative mortality rate was 3% and the hospital mortality rate was also 3%. The postoperative course was complicated with pleural effusion in 10%, bile leakage in 4%, subphrenic abscess in 4%, and upper gastrointestinal bleeding caused by gastritis in 1% of the patients. The actual survival rate for the 103 cases was 84% for 350 days and 28% for 1400 days. However, in the group with asymptomatic HCC with an average tumor size of 3.35 +/- 1.49 cm in diameter, the rate was 92% for 350 days and 44% for 1400 days. In the group with symptomatic HCC with an average tumor size of 10.6 +/- 5.1 cm in diameter, the rate was 76% for 350 days and 8% for 1400 days. The survival rate of the group with asymptomatic HCC was far better than that of the group with symptoms (p less than 0.05). In analysis of factors that might affect the patient's survival, only second or third operations (p less than 0.05), typical gross findings of tumor appearance (p less than 0.05), and an adequate margin were closely related (p less than 0.001). Neither the tumor size, the status of accompanying liver cirrhosis, the tumor location, nor the patient's sex and age affected the patient's survival (all p greater than 0.05).

Adult↗
PubMed1986

T-lymphocytes subpopulation before and after surgical removal of hepatocellular carcinoma.

This study included 16 histologically confirmed hepato-cellular carcinoma (HCC) patients. At the same time, 32 normal healthy individuals and 20 asymptomatic hepatitis B surface antigen (HBsAg) carriers were served as control groups. The study disclosed that T cells, OKT4 cells and the ratio of OKT4 cells/OKT8 cells in peripheral venous blood of HCC patients before surgery were lower than that of either normal control or asymptomatic HBsAg carriers. The difference was statistically significant. The T cells, OKT4 cells and the ratio of OKT4 cells/OKT8 cells of 4 HCC patients with positive HBeAg did not show further decrease as compared with that of 12 HCC patients with negative HBeAg. Periodic examination of T cells, OKT4 cells and OKT8 cells in 16 HCC patients after surgical removal of hepatocellular carcinoma tumor revealed that preoperative depressed T cells will decline further in the first postoperative week, but it will gradually increase to near normal range in the fourth or fifth postoperative week. However, OKT4 cells still remained in depressed state during the postoperative observation period. In the conclusion, it has been suggested that the derangement of T-cell subsets observed in HCC patients is not related to either HBsAg or even HBeAg. It can be either precondition to HCC formation or further follow up period being needed to look for the change of OKT4 cells.

Adult↗
PubMed1985

Seven days of ceftriaxone therapy is as effective as ten days' treatment for bacterial meningitis.

Seventy-nine children were enrolled in a study to compare seven vs ten days of ceftriaxone therapy for bacterial meningitis. On the basis of a computer-generated list of therapy assignments, 35 children with Haemophilus, pneumococcal, or group B streptococcal meningitis each were assigned to seven- or ten-day treatment regimens; nine children with meningococcal meningitis received seven days of therapy. The population characteristics and etiologic agents were similar for the two treatment groups, as were also the findings on examination and culture of cerebrospinal fluid at completion of therapy. There were no significant differences in the frequency and types of neurological complications between the two treatment groups; four patients in each group had two or more neurological abnormalities. The rates of nosocomial infections and prolonged and secondary fever were similar in those who received seven days of therapy compared with patients treated for the conventional ten days. Diarrhea occurred in 44% of those receiving the drug. Patients treated with the seven-day regimen were discharged from the hospital approximately two days earlier than those with the ten-day regimen.

Bacterial Infections↗
PubMed1985

Renin inhibitors. Syntheses of subnanomolar, competitive, transition-state analogue inhibitors containing a novel analogue of statine.

Analogues of the renin octapeptide substrate were synthesized in which replacement of the scissile dipeptide with (3S,4S)-4-amino-3-hydroxy-6-methylheptanoic acid (statine, Sta) transformed the substrate sequence into potent, transition-state analogue, competitive inhibitors of renin. Synthesis and incorporation of the cyclohexylalanyl analogue of Sta, (3S,4S)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid (ACHPA), gave the most potent inhibitors of renin yet reported, including N-isovaleryl-L-histidyl-L-prolyl-L-phenylalanyl-L-histidyl-ACHPA-L -leucyl-L- phenylalanyl amide [Iva-His-Pro-Phe-His-ACHPA-Leu-Phe-NH2,3], with renin inhibitions of Ki = 1.6 X 10(-10) M (human kidney renin), IC50 = 1.7 X 10(-10)M (human plasma renin), IC50 = 1.9 X 10(-9)M (dog plasma renin), and IC50 = 2.1 X 10(-8) M (rat plasma renin). This inhibitor 3, containing ACHPA, was 55-76 times more potent vs. human renin than the comparable Sta-containing inhibitor 1 and 17 times more potent vs. dog renin than 1. Inhibitor 3 lowered blood pressure in sodium-deficient dogs, with in vivo potency 19 times that shown by 1, in close agreement with the relative in vitro potencies. Structure-activity results are presented that show the minimal N-terminus for these inhibitors. An ACHPA-containing pentapeptide, N-[(ethyloxy)carbonyl]-L-phenylalanyl-L- histidyl-ACHPA-L-leucyl-L-phenylalanyl amide [Etoc-Phe-His-ACHPA-Leu-Phe-NH2,8], retained subnanomolar inhibitory potency. Molecular modelling studies are described that suggested the design of ACHPA.

Amino Acids↗
PubMed1985

Intraoperative hepatic ultrasonography--an indispensable procedure in resection of small hepatocellular carcinomas.

Hepatic ultrasonography (US) was performed during laparotomy in 47 patients with hepatocellular carcinomas (HCC) less than 5 cm in size. It detected more tumors than did preoperative US and other imaging modalities. In this series, 45.9% of HCCs smaller than 3 cm and 14.2% of those between 3 and 5 cm were invisible and impalpable during laparotomy, and another 15.5% of the total of HCCs were only partially visible or equivocally palpable; thus they needed intraoperative US to make a three-dimensional localization of the tumors. We concluded that, in the resection of small HCCs, intraoperative US should serve as a routine procedure.

Adult↗