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Biomedical subjects

S T Lin

Publications and source records attributed to S T Lin.

At least 37 records · Page 2Linked to original sources
PubMed1991

The effect of extraction solvent on the mutagenicity of airborne particles.

Two different solvents (acetone and dichloromethane) were compared for their efficacy in extraction of mutagenic compounds from airborne particulate samples. Their mutagenicity was examined with Salmonella typhimurium TA98 in presence or absence of S9 mix. The total mutagenic activity of the acetone extract was 1.8-7.0-fold that of the dichloromethane extract. The content of 1-nitropyrene, 1,6-dinitropyrene, dibenzo[a,h]anthracene and indo[1,2,3-c,d]pyrene in acetone extracts of airborne particulate samples was 3.8-, 3.6-, 6.6- and 1135-fold that of dichloromethane extracts, respectively. 1,8-Dinitropyrene, benzo[a]pyrene, chrysene, benzo[a]fluoranthene, benzo [a] anthracene, and benzo[g,h,i]perylene were found in the acetone extract, but were negative in the dichloromethane extract under the same conditions. However, the amount of pyrene in the dichloromethane extract was much higher than in the acetone extract. These results indicate that the extraction efficacy of 1-nitropyrene, dinitropyrenes and benzo[a]pyrene is higher with acetone than with dichloromethane. This may be the reason why acetone is the most effective solvent in extraction of mutagens from airborne particulate samples.

Acetone↗
PubMed1991

Delay of diagnosis of growth hormone deficiency in Taiwan.

In view of the importance of early detection of growth hormone deficiency, the height and age at the first pediatric endocrinologic clinic visit of 45 patients with growth hormone (GH) deficiency between January 1988 to December 1989 were retrospectively analyzed. Twenty-three patients with idiopathic GH deficiency had a median age of 13 years (range, from 3.8 to 29.9 years) at their first visit and a median height standard deviation score (SDS) of -3.87 (-2.14 to -7.93). Nineteen children with hypothalamopituitary tumors at their first visit, at a median of 2.17 years (0.42 to 7.83 years) after diagnosis of the tumor, had a median height SDS of -3.15 (-0.58 to -4.70). Three children with GH deficiency secondary to cranial irradiation at their first visit, at 8.17 years (1.33 to 10 years) after treatment for their malignancy, had a height SDS of -3.15 (-2.13 to -3.72). It is well known that the earlier the replacement therapy is begun in such patients, the better the prognosis is for final adult height. Regular height measurement and routine screening for shortness at school entry may overcome this delay in diagnosis. In addition, patients who have received cranial irradiation or had hypothalamopituitary tumors should be regularly measured and studied if their height velocities become subnormal. Physicians dealing with children should keep the possibility of growth hormone deficiency in mind when examining a short child.

Adolescent↗
PubMed1991

Detection of beta-globin gene mutations by polymerase chain reaction.

The polymerase chain reaction and oligonucleotide probe hybridization technique were applied to the detection of two common mutations of the beta-globin gene found in Chinese, namely the 4-base pair deletion at the 41-42 codons and the C to T substitution at nucleotide 654 of IVS-2. The accuracy of the method was established using beta-thalassemia cases with known mutations or haplotypes of the restriction fragment length polymorphism (RFLP). A further 11 cases of thalassemia intermediate and thalassemia minor were then analysed with the same approach. Our results showed that 5 of the 11 cases carried the TCTT-deletion at codons 41-42. Our method is economical both in terms of materials and time needed and in an alternative to the use of the molecular RFLP approach in the prenatal diagnosis of beta-thalassemia.

Base Sequence↗
PubMed1991

Corneal trauma from overnight wear of rigid or soft contact lenses.

To evaluate the mechanical or biochemical insult to the cornea induced by overnight rigid gas permeable (RGP) or soft contact lens (SCL) wear, punctate, stipple staining and corneal blotting were evaluated by biomicroscopy in a group of 23 subjects who participated in a single overnight in-laboratory test session. The soft lens-wearing corneas typically showed greater area of staining along with corneal blotting in comparison to RGP-wearing corneas which showed smaller areas of corneal staining, even in the presence of RGP adherence, and no corneal blotting. We investigated the effect of hypoxia on corneal staining by having subjects wear an RGP lens of Dk = 150 on one eye and a soft lens of Dk = 9 on the fellow eye. Pachometry measurements immediately following eye opening showed an average central corneal swelling of 5 percent for the RGP lens-wearing eye and an average of 11 percent for the SCL-wearing eye. It is likely that the differences in corneal effects of RGP and SCL overnight lens wear are the result of differences in the nature of rigid versus soft contact lens adherence.

Adult↗
PubMed1991

Protein accumulation on disposable extended wear lenses.

We investigated protein accumulation on disposable extended wear contact lenses. Fifteen volunteers were fit with one low water content, non-ionic lens (Bausch & Lomb's SeeQuence) randomly assigned to one eye and a high water content ionic lens (Vistakon's Acuvue) assigned to the fellow eye. During the first 7 weeks of extended wear the lenses were removed weekly for sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of protein deposition, and replacement lenses were inserted. Four subjects completed additional test sessions of 1 minute, 15 minutes, 24 hours, and 1 week extended wear. Lysozyme accumulation, as measured by SDS-PAGE, increased with wearing times up to one week on all Acuvue lenses, but after 24 hours wear lysozyme accumulation did not increase on the SeeQuence lens. Proteins falling into the reported molecular weight ranges of albumin, PMFA, IgG, IgA (sec), lactoferrin and subunits of protein G were evident on all gels at 1 minute of wear, but these protein groups did not have a detectable increase in deposition after 24 hours wear for either the SeeQuence or the Acuvue lenses. In most cases, the protein accumulation evident from SDS-PAGE analysis was not observable by biomicroscopy using standard clinical methods. A few patients reported preference for the initial comfort and vision achieved by the Acuvue lens, but no preference was found after adaptation.

Adult↗
PubMed1990

Initial in vivo tear protein deposition on individual hydrogel contact lenses.

We investigated and compared the initial composition, morphology, and time course of deposits on individual soft contact lenses of different water contents and surface charges in order to evaluate the potential for antigenic reactions and to predict the optimal frequency of lens replacement. Newly manufactured lenses were worn for graduated periods of time from 1 min to 8 h by subjects who were first adapted to daily wear soft lenses. The morphology and composition of the deposits were analyzed by histological staining, light microscopy, scanning electron microscopy (SEM), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) with silver nitrate staining, and immunofluorescence microscopy. The protein bands of the acrylamide gels were divided according to their molecular weights into six groups which have been defined in the literature from tear analyses by electrophoretic techniques and include lysozyme, proteins migrating faster than albumin (PMFA), protein G, albumin, lactoferrin, and other proteins heavier than albumin such as Ig-G and secretory Ig-A. Specific proteins (lysozyme, PMFA, and protein G) were detected on individual lenses after as little as 1 min of wear. There was an increasing amount of protein deposited as the wearing time increased. Differences in the rates and amounts of deposition were more dependent on lens water content and ionic characteristics than on intersubject differences. Such early significant protein deposition may occur in wearers of disposable lenses as well as in those subject to complications due to accumulation of protein.

Adolescent↗
PubMed1990

[Study on chemosensitivity test (in vitro) of cultured human urogenital carcinoma cell lines by MTT assay].

MTT assay was performed simultaneously with a clonogenic assay to assess its validity on chemosensitivity test by using the cultured human urogenital carcinoma cell lines PC3, 19PC93, DU145 and T24. The drugs used were carboquone (CQ), adriamycin (ADM), cisplatin (CDDP) and pepleomycin (PLM). Dose response curves were drawn and 50% inhibition doses (ID50) were calculated and examined by t-test. The correlations between the results obtained from both assays were observed. For comparing antitumor intensity of drugs with each other, predicted antitumor activity (PAA) was calculated from the peak plasma concentration of the clinically used dose. High cytotoxicity of drug was considered if PAA greater than or equal to 1 was observed. The optical density (OD) was almost directly proportional to the number of cells. Good correlations between OD and colony number, or between ID50 from both assays were noted although the clonogenic assay is more sensitive than the MTT assay. Relative resistances between cell lines to a drug observed by the clonogenic assay were also maintained by the MTT assay. The chemosensitive intensity was CQ greater than ADM greater than CDDP greater than PLM, and the sequence was similar in both assays. PC3, DU145 and T24 were sensitive to CQ but 19PC93 was to CQ and ADM. Therefore, MTT assay was concluded as a useful method for chemosensitivity test, although the problem of normal cell contamination was left to be solved for clinical use.

Antineoplastic Agents↗
PubMed1989

The effect of time, patching, and lens flexibility on RGP lens adherence.

The effects of time, eye patching, and lens flexibility on rigid lens adherence was evaluated in five overnight, in-laboratory test sessions. Patching was investigated with a group of 11 subjects in two overnight test sessions. Sleep time and lens flexibility were investigated in three separate overnight test sessions with two groups of subjects wearing two lens types of fluorosilicone materials (Dk 92 and 60). Adherence occurred in a significant portion of eyes within a 2-hour time period, and the incidence increased throughout the night. There was no significant difference between the incidence of adherence for lenses of a flexible material compared to lenses of a more rigid material (p greater than 0.6, X2 test), nor did patching have a significant influence on the incidence of adherence. The mechanism of lens adherence may be related to several factors including arbitrary lens movement to a peripheral corneal position, the creation of a geometric spacing between the lens and the eye, lid forces producing a negative pressure, and an increase in tear viscosity throughout the night.

Adhesiveness↗
PubMed1986

Screening of anti-HTLV antibody in sera of normal individuals and patients with malignancies in Taiwan.

In the present study an immunofluorescence using KH-2 cells as target cells, has been developed for the screening of 1200 serum samples from normal individuals and 450 of cases from patients with various malignancies. The positive anti-HTLV-I antibody rate in the former group is 0.083% (1/1200) and while in the latter it is found to be 1.8% (8/450) (including 3 adult T-cell leukemia/lymphoma cases of the 92 hematopoietic and 5 of 358 non-hematopoietic malignancies). The differences between the two groups are found to be significantly different (p value is less than 0.0001). In addition to the 3 adult T-cell leukemia/lymphoma cases, the 5 seropositive cancer patients are of 5 different diseases. We have searched for the adult T-cell leukemia virus antigen and the p19 core protein in lymphoid cells of seropositive persons and the only positive cases were from cells of two proven adult T-cell leukemia (ATL) patients. Our results suggest that Taiwan is not an endemic area of adult T-cell leukemia virus and that KH-2 cells may be used for the detection of anti-HTLV-I antibodies.

Adolescent↗
PubMedDate not supplied

A case of Morgagni hernia presenting as pneumonia.

Morgagni-type diaphragmatic hernias are rare. The overwhelming majority are discovered in children who usually present with pneumonia or sepsis. We report an unusual case of a 57-yr-old woman with a Morgagni hernia presenting with pulmonary symptoms. Complicating the clinical picture, the pneumonia delayed the definitive diagnosis until a lateral chest X-ray study revealed loops of bowel in the right lower lung fields. It is important to entertain abdominal etiologies in the differential diagnosis of a thoracic density.

Diagnosis, Differential↗
PubMedDate not supplied

Clinical use of single-dose surfactant TA therapy for premature infants with severe respiratory distress syndrome.

A single dose of surfactant TA was given as rescue therapy to four small premature infants with severe respiratory distress syndrome requiring mechanical ventilation. Birth weights ranged from 810 to 1200 gm. The dose of 100-120 mg/kg was given at the mean age of 5 hours, with range of 3 to 7 hours. Following surfactant therapy, there was a significant improvement (p < 0.05) in a/APO2 (raising from 0.11 +/- 0.05 before treatment to 0.34 +/- 0.19 at 6 hours after treatment). There was also a significant reduction in the severity of respiratory distress syndrome at 24 hours post-therapy. One baby died of sepsis at 40 hours of life; one survived without complications. The other two cases developed severe bronchopulmonary dysplasia later. We concluded that early use of exogenous surfactant is beneficial in small premature infants with severe respiratory distress syndrome.

Female↗