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Biomedical subjects

P Tseng

Publications and source records attributed to P Tseng.

14 recordsLinked to original sources
PubMed1999

Development and function of autospecific dual TCR+ T lymphocytes.

Recent studies have challenged the long held concept that each T lymphocyte expresses on its surface only a single, unique alphabetaTCR. Dual TCR+ T cells have been recognized, however, their origin and potential to escape screening for self-reactivity remain obscure. We now report the thymic generation of dual alphabetaTCR+ T cells in the H-2Db/H-Y-specific TCR transgenic (Tg) mouse. Dual TCR+ thymocytes were positively selected less efficiently than single TCR+ thymocytes, although a subset attained maturity. Importantly, when TCR Tg mice were bred onto a negatively selecting background, auto-specific cells survived central deletion and matured as CD4+ dual TCR+ cells. These cells were autoreactive when CD8 expression was restored. The existence of autospecific, dual TCR+ T cells may have implications for the maintenance of self tolerance.

Animals↗
PubMed1999

Excimer laser photorefractive keratectomy for the correction of myopia.

AIM OF STUDY: To ascertain the efficacy, predictability, safety and stability of photorefractive keratectomy (PRK) for the correction of myopia. METHODS: Nine-hundred and seventy-one eyes of 628 patients had PRK performed for the correction of myopia. The mean pre-operative myopia was -5.7 D +/- 2.21 D (range -1.0 D to -15.25 D). The mean attempted correction was -5.0 D +/- 1.9 D (range -1.0 D to -9.90 D). RESULTS: Four-hundred and sixty-seven eyes had a follow-up of 6 months or more. Ninety-three percent of low myopic eyes (pre-operative myopia of less than or equal to 6.0 D) and 75% of high myopic eyes (pre-operative myopia of more than 6.0 D) attained an unaided visual acuity of 6/12 or better. Seventy-four percent of low myopic and 50% of high myopic eyes were within 1 D of the intended correction. The mean post-operative refraction at 6 months was 0.60 D +/- 1.46 D. Eight eyes in the high myopia group and 1 eye in the low myope group lost 2 or more lines or best-corrected visual acuity. CONCLUSION: PRK was safer and produced better results for low myopes.

Adult↗
PubMed1997

The analgesic efficacy of ibuprofen in periodontal surgery: A multicentre study.

The efficacy of a non-steroidal anti-inflammatory agent, ibuprofen, was evaluated in pain control following periodontal surgery. This type of agent acts peripherally by inhibiting the release of prostaglandins and minimizing the local inflammatory response. Thus there may be an advantage in pre-treatment administration of the drug so as to delay or even prevent postoperative pain. The study was multicentre, involving a Public Hospital Periodontal Unit, two specialist periodontal practices in Sydney, NSW, and two in Canberra, ACT. One hundred and twenty-seven patients who were to undergo periodontal surgery were randomly given either two 200 mg tablets of ibuprofen or two matching placebo tablets at least 30 minutes before administration of local anaesthesia. The procedure was double blind: neither the patient nor the clinician was aware of the tablet identity. Postoperatively, all patients were given labelled ibuprofen for pain relief, but were randomly divided into two groups: As directed who were instructed to take the drug regularly for two days postoperatively, and As required, who were to take the drug only if needed for pain relief. All patients completed a diary recording quantity and time of medication, and regular assessment of pain experience utilizing a visual analogue scale. The As directed group showed no significant difference in pain experience between pre-operative and post-operative only medication, but the As required group experienced significantly less pain and requirement for medication if the ibuprofen was administered pre-operatively.

Adolescent↗
PubMed1997

Photorefractive keratectomy for the treatment of compound myopic astigmatism using the ablatable mask.

Eight eyes of 8 patients with compound myopic astigmatism were treated with excimer laser photorefractive keratectomy (PRK) using a hand-held ablatable mask in conjunction with the Summit excimer laser. The attempted correction ranged from -1.25 to -400 dioptres (D) of astigmatism and 0 to -8.00 D of myopia. All eyes had attained at least 6 months of postoperative follow-up. Five of the 8 eyes achieved an unaided visual acuity of 6/12 or better. Postoperative refractions ranged from -0.50 to -3.50 D of refractive cylinder and from +0.50 to -3.75 D of spherical error. Decentration of the ablation zone was encountered in 3 eyes due to shifts in patients' fixation. Technical difficulty with the use of the hand-held ablatable mask limited the widespread application of this procedure and it has now been superseded by newer excimer laser systems which can correct astigmatism without having to employ a mask. Despite this, because of the theoretical ability of the mask to correct any form of refractive error, the concept of the mask shape transfer process will remain as a potential alternative in refractive surgery, especially for correction of hyperopia and hyperopic astigmatism.

Adult↗
PubMed1994

Hydrolyzed lactalbumin-based oral rehydration solution for acute diarrhoea in infants.

The addition of different organic substrates to standard glucose oral rehydration solution (G-ORS) has been shown to improve the intestinal absorption of sodium and water, and thereby decrease stool losses. Therefore, we evaluated, in infants with acute diarrhoea, the safety and efficacy of three oral rehydration solutions (ORS) which had the same concentrations of electrolytes (with sodium 60 mmol/l) but different substrates of proteins and carbohydrates. One solution (LAD-ORS) contained hydrolyzed lactalbumin (LAD) with maltodextrin and sucrose, a second (MS-ORS) was identical but without LAD and a third (G-ORS) was standard glucose ORS. The three solutions were compared in a double-blind, randomized trial in 74 hospitalized well-nourished children in Panama and the United States. All three oral rehydration solutions were equally efficacious and safe in these children, 54% of whom were infected with rotavirus. There was no suggestion that hydrolyzed lactalbumin or maltodextrin provided any advantage over glucose-ORS in terms of stool output or in duration of diarrhoea. We conclude that all three solutions are efficacious in the therapy of acute diarrhoea in infants.

Acute Disease↗
PubMed1993

Oral and dental complications in dieting disorders.

This study investigated the oral status and dental complications in patients with both anorexia and bulimia nervosa. Results revealed that prolonged periods of dietary restraint in anorexic patients did not result in changes to bacteria associated in dental caries. Furthermore, patients did not have lower decay rates or salivary flow but did have more acidic saliva. Moreover, both groups of patients revealed changes indicative of gingivitis and gingival recession but not necessarily of periodontitis when compared to control subjects.

Adolescent↗
PubMed1993

Non-puerperal uterine inversion--a case report.

A rare case of non-puerperal uterine inversion caused by a large fundal leiomyoma in a 36-year-virgo intacta resulting in intractable haemorrhage was reported. After a myomectomy, attempts to reduce the inversion vaginally by transecting the anterior and posterior cervix was unsuccessful and a laparotomy was performed. The inversion was successfully corrected with return of normal function of the uterus.

Adult↗
PubMed1991

Single-dose concentrations of tinidazole in gingival crevicular fluid, serum, and gingival tissue in adults with periodontitis.

Previous studies have shown that metronidazole is effective in the treatment of subgingival microflora associated with destructive periodontitis. The aim of this study was to determine whether tinidazole, a close analogue of metronidazole, would reach sufficient concentrations in serum, gingival crevicular fluid, and gingival tissue, to inhibit putative periodontopathic bacteria. Ten adult patients with moderate to advanced periodontitis took a single 2-g dose of tinidazole orally. Samples were assayed by high-performance liquid chromatography. The concentrations of tinidazole in serum and GCF were in a similar range (3.2-46.5 micrograms/mL). Tinidazole was not detected in the GCF in three of the patients. The drug was found in gingival tissue obtained at two h (0.17 +/- 0.14 micrograms/mg) and six h (0.15 +/- 0.18 micrograms/mg) after oral administration. The mean concentration of tinidazole in serum at 24 h (13 +/- 3.0 micrograms/mL) is greater than the minimum inhibitory concentration for anaerobic bacteria as reported by others. The present data suggest that a single 2-g oral dose of tinidazole may lead to the presence of potentially bactericidal levels of tinidazole for up to 24 h in the periodontal pockets of some patients with periodontitis.

Administration, Oral↗
PubMed1990

The cytokine CSF-1 (M-CSF) expressed by endometrial carcinomas in vivo and in vitro, may also be a circulating tumor marker of neoplastic disease activity in endometrial carcinoma patients.

Endometrial epithelial cell expression of CSF-1 and FMS antigens was studied in vivo and in vitro in 24 human endometrial carcinoma and 11 benign endometrial biopsy specimens. Twenty-one of 24 adenocarcinomas and 4 of 11 benign lesions stained positively (by IHC) with rabbit anti-human CSF-1 antibodies, while all 24 carcinomas and 3 out of 11 benign lesions (all secretory endometrial specimens) showed significant IHC staining (1+ or greater) of epithelial elements and tissue macrophages with a mouse anti-FMS (CSF-1 receptor) monoclonal antibody. CSF-1 levels in plasma from endometrial carcinoma patients (85 samples, 24 patients) were also found to be markedly elevated (some greater than 100 ng/ml) in patients with active or recurrent disease. In vitro, several endometrial carcinoma cell lines were shown to express FMS complementary transcripts and FMS antigen which were very similar if not identical to those expressed in choriocarcinoma cell line positive controls. Autocrine and paracrine effects mediated by tumor or stromally produced CSF-1 and a tumor epithelial cell CSF-1 receptor may therefore contribute to the biological behavior of endometrial neoplasms in vivo and in vitro.

Adenocarcinoma↗
PubMed1989

Microcolposcopy vs. cone histology in evaluation of the endocervix in women with inadequate colposcopy or positive endocervical curettage.

Microcolposcopy (MC) can magnify cervical and endocervical surface cytology from 1:1 to 1:150. MC examination of the exocervix has been found to be equivalent to colposcopy. We compared MC to cone histology in evaluating the endocervix in women with inadequate colposcopy or positive endocervical curettage (ECC). Thirty-one patients were studied. All had standard colposcopic examinations that were deemed inadequate or resulted in positive ECC. MC was then performed and followed by cervical conization. Histologic specimens were obtained from serial sections of the surgical specimen. All 31 patients had adequate MC examinations. MC had a positive predictive value of 87% in evaluation of the endocervix as compared to cone histology specimens. Sensitivity and specificity were 99% and 70%, respectively. MC had a sensitivity of 92% in identifying the cervical segment with the worst histologic diagnosis. MC can evaluate the endocervix in patients with inadequate colposcopy or positive ECC. Biopsy of the worst histologic region in those patients can be guided by MC examination; thus, conization of the cervix can be avoided.

Adult↗
PubMed1987

Microcolpohysteroscopy compared with colposcopy in the evaluation of abnormal cervical cytology.

Microcolpohysteroscopy allows one to observe the cervix and endocervix at magnifications of 1:1-1:150. More important, it permits examination of the squamocolumnar junction when it is obscured within the endocervix. This preliminary report compares standard colposcopy with a microcolpohysteroscopy technique in 65 patients with abnormal Papanicolaou smears. Using contact microcolpohysteroscopy, the clinician can map out geographically entire cervical intraepithelial neoplastic lesions; locate correctly the epicenter of most lesions; and in cases of inadequate colposcopy, visualize the squamocolumnar junction within the cervix. Microcolpohysteroscopy was equivalent to traditional colposcopy in detecting abnormal histology. This technique predicted lesions with viral cytopathic effects, which correlated with histology in 83% of cases. The results of this study suggest that microcolpohysteroscopy is a diagnostic tool that can precisely qualify and localize a cervical lesion.

Adolescent↗
PubMed1984

Antepartum fetal heart rate response to sound stimulation: the acoustic stimulation test.

The fetal heart rate acceleration response to an acoustic stimulation was compared to the traditional nonstress test in regard to pregnancy outcome, as reflected by the incidence of intrapartum fetal distress, meconium staining of the amniotic fluid, 1- and 5-minute Apgar scores, and perinatal mortality. Fetuses with spontaneous or sound-generated reactivity had comparably good outcomes with respect to all outcome measures investigated. Fetuses who lacked spontaneous or sound-stimulated reactivity had an increased risk for intrapartum fetal distress. The acoustic stimulation test is a safe and rapid test of fetoplacental sufficiency that appears to perform comparably to the nonstress test. The acoustic stimulation test significantly shortens total antepartum testing time and expense.

Acoustic Stimulation↗
PubMedDate not supplied

Photorefractive keratectomy for myopia of 6 to 12 diopters.

To conduct a prospective, nonrandomized clinical trial to assess the efficacy, stability and safety of the use of excimer laser photorefractive keratectomy (PRK) to correct myopia of greater than -6.00 diopters (D) in Singapore. Two hundred thirty-three eyes of 176 patients with a mean preoperative spherical equivalent refraction of -8.70 +/- 2.3 D (range, -5.75 D to -18.13 D) underwent PRK with a 193nm ArF excimer laser (ExciMed, Summit) for myopic corrections of between -6.20 D and -11.90 D. The first 66 of 233 eyes that reached at least 1 year of postoperative follow up are reported. One year postoperatively, the mean manifest spherical equivalent refraction was -1.50 D +/- 1.90 D (range -6.25 D to +3.25 D); 34% of eyes were within +/- 1.00 D of attempted correction; uncorrected visual acuity was 20/40 or better in 75% of eyes. No eyes lost two or more Snellen lines of spectacle corrected visual acuity. Central corneal haze was mild in 20% of eyes and moderate in 3% of eyes. Five eyes developed ocular hypertension that subsequently resolved with treatment. Excimer laser PRK is reasonably effective and safe in the treatment of -6.00 D to -12.00 D of myopia. However, it is less accurate than PRK in eyes with low to moderate myopia and is more likely to result in significant corneal haze.

Adult↗