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Biomedical subjects

W J Lynch

Publications and source records attributed to W J Lynch.

At least 37 records · Page 2Linked to original sources
PubMed1999

Evaluation of interstitial diode laser therapy for treatment of benign prostatic hyperplasia.

In the last decade, a number of new device technologies were developed for benign prostatic hyperplasia (BPH) therapy. These technologies were introduced in an effort to reduce the morbidity of BPH therapy associated with conventional electrocautery transurethral resection of the prostate (TURP). While morbidity is reduced, the aim of new therapy is to achieve near equivalence in efficacy of outcome measures, namely, improved voided flow rate and reduced symptom score. To gain acceptance by urologists, these technologies should be easy to apply and should reduce the economic cost of BPH treatment. The Indigo 830e diode laser system offers simplified laser therapy from a miniaturized solid-state system. This pilot study demonstrates outcome equivalence to TURP in preliminary evaluation and shows an acceptable side effect profile.

Aged↗
PubMed1998

A novel paradigm to investigate regulation of drug intake in rats self-administering cocaine or heroin intravenously.

The purpose of this experiment was to investigate the regulation of drug intake in rats (n = 20) self-administering heroin or cocaine during daily 5-hr sessions. Operant chambers were equipped with 2 levers and associated stimulus lights. A response on the lever with stimuli signaling an increase in dose size increased the infusion duration by 3 s, and a response on the lever with stimuli signaling a decrease in dose size decreased the infusion duration by 3 s. Results showed that daily and hourly drug intake for cocaine and heroin groups were relatively constant. Significant correlation coefficients were obtained for heroin and cocaine groups for the relationship between interdose interval (IDI) and infusion duration (dose size). These findings indicate that subjects regulated their drug intake by adjusting IDI throughout drug self-administration sessions.

Animals↗
PubMed1998

Effects of amphetamine, butorphanol, and morphine pretreatment on the maintenance and reinstatement of cocaine-reinforced responding.

Three groups of rats (N = 23) self-administered intravenous cocaine (0.4 mg/kg/infusion) during the initial 2 hr of daily 7-hr sessions. During the remaining 5 hr of these sessions, responding produced saline infusions. On test days, each rat was pretreated with an assigned dose of either butorphanol, morphine, amphetamine, or saline before the self-administration session followed by a priming injection of cocaine (3.2 mg/kg i.v.) or saline at the beginning of the 4th hr. Results showed that both amphetamine (0.5, 1.0, and 2.0 mg/kg) and morphine (0.3, 1.0, and 2.0 mg/kg) pretreatment dose-dependently reduced cocaine self-administration whereas only amphetamine affected (increased) reinstatement responding. Butorphanol pretreatment (8 mg/kg) suppressed cocaine self-administration and blocked the effect of the cocaine priming injections on pretreatment testing days. These findings indicate that (a) pretreatment drugs with similar stimulus properties potentiate reinstatement of responding and (b) pretreatment drugs can differentially affect maintenance and reinstatement of responding.

Amphetamine↗
PubMed1998

Ethanol consumption in rats when dose size is under subject control.

Rats orally self-administered ethanol when they could control dose size as follows: A lever press initiated a trial; a press on 1 lever increased the previous trial duration by 30% whereas a press on a 2nd lever decreased the previous trial duration by 30%. During a trial, rats could drink either water, 8%, or 16% (wt/vol) ethanol (ETOH) from a lick-sensitive fountain. Mean per session intake of 8% and 16% ETOH was 0.8 g/kg and 1.3 g/kg, respectively. Water intake was negligible. Rats did not show a tendency to maintain a particular trial duration, nor did they adjust intertrial intervals to previous dose size (number of licks). When trials were collected into bouts, a positive relationship was found between bout size and interbout interval; this relationship was statistically significant for the 8% but not the 16% ETOH condition.

Alcohol Drinking↗
PubMed1997

Renal cryotherapy in a sheep model; a feasibility study.

PURPOSE: This study was designed to evaluate the safety and efficacy of renal cryotherapy as a possible treatment of renal malignancy with preservation of renal parenchyma. MATERIALS AND METHODS: Ten Merino sheep were anaesthetised and the right kidney was exposed through a retro-peritoneal approach. A 5 mm. cryotherapy probe (LCS 3000 Cryotec UK) was inserted into the lower pole of the kidney and freezing was undertaken to form an iceball 5 cm. in diameter. RESULTS: There was no mortality and no complications were observed. A transient rise in creatinine was observed post-operatively. The sheep were euthenased at 4 weeks and at necropsy macroscopic examination revealed a contracted, fibrotic wedge shaped lesion of 3 cm in diameter. Histological examination of the "cryolesion" revealed a central area of coagulative necrosis and a 5 mm rim of partial necrosis with preservation of renal tubules. CONCLUSION: We conclude that renal cryotherapy is safe and can achieve effective renal necrosis in the sheep model.

Animals↗
PubMed1996

In vitro and in vivo assessment of urethral warming catheters for the transperineal cryoablation of prostatic carcinoma.

OBJECTIVE: To evaluate the two most common urethral warming catheters currently available for their effectiveness in preventing urethral injury in an animal model and thus during transperineal cryosurgery for the treatment of prostate cancer. PATIENTS, MATERIALS AND METHODS: The warming efficiency of the variable-diameter thin latex-balloon catheter (Cook, Australia) and the fixed-diameter PVC catheter (Candela, USA) were evaluated in a water-bath. A sheep model was then used for subsequent experiments to further evaluate the better catheter. The technique used for the insertion of the Cook catheter in a series of 33 patients treated with prostate cryosurgery is also described. RESULTS: In vitro, the Cook catheter was more effective (P < 0.01) than the Candela catheter in preventing localized cooling. In vivo, results in five animals showed that the urethral epithelium was viable in all sections that had been protected by the catheter and focally denuded or necrotic in those sections not protected, with each animal used as its own control (P < 0.01 Fisher's exact test). The 33 patients treated while using the Cook catheter had no subsequent complications. CONCLUSION: The urethral warming catheter currently in use for prostatic cryosurgery in Australia is more effective in vitro than its competitor and is effective in preventing urethral injury in vivo.

Catheterization↗
PubMed1996

Critical temperature for in vivo cryoablation of human prostate cancer in a xenograft model.

OBJECTIVES: To assess the in vivo sensitivity of human prostate cancer cells (PC3) to cryoablation and thus define the minimum temperature needed to prevent the recurrence of cancer after percutaneous transperineal radical prostatic cryoablation. MATERIALS AND METHODS: Twenty-five male nu/nu mice were inoculated by a subcutaneous injection with 5 x 10(5) PC3 cells. After 3 weeks the tumours (mean area 60.4 mm2, SEM 5.7) were frozen using a 3 mm cryotherapy probe (LCS 3000 Cryotech UK) to temperatures ranging from 0 degrees to -40 degrees C. RESULTS: No tumours recurred in seven mice which had tumours frozen to < -15 degrees C. There were eight recurrences in 15 mice which had tumours frozen to between 0 degree and -15 degrees C, and all were confirmed histologically. CONCLUSIONS: The minimum temperature required to prevent recurrence of tumours from human prostate cancer cells was < -15 degrees C in this in vivo mouse model.

Animals↗
PubMed1993

Comparison of laparoscopic and open ligation of the testicular vein.

Scrotal varicoceles undoubtedly contribute to subfertility in an as yet undefined group of patients. The best method of treatment of varicoceles, however, remains controversial. Laparoscopic testicular vein ligation has recently been offered as a new option. We examined the feasibility of laparoscopic testicular vein ligation (n = 11) compared with standard high ligation (n = 11). The mean post-operative stay in the open group was 25.6 h compared with 7.1 h in the laparoscopic group. Analgesic requirements were a mean of 4.73 Co-proxamol tablets for the open group and 0.18 tablets for the laparoscopic group. All operations were successful. Laparoscopic ligation of the testicular vein is an effective treatment of varicocele with decreased post-operative morbidity.

Adult↗
PubMed1992

The quality of life after radical radiotherapy for bladder cancer.

The quality of life in 72 patients who had shown a complete response to radiotherapy, using a modified bladder symptom score and the Nottingham health profile, was compared with the quality of life in a similar control group matched for age and sex. There was no significant difference in either group. The records of 69 patients who had undergone post-radiation salvage cystectomy were reviewed, looking specifically at surgical complications. There were 3 post-operative deaths (5%), 3 pulmonary emboli and 3 fistulae--with some overlap of complications. Five patients who underwent cystectomy for intractable symptoms in the apparent absence of recurrent tumour were found to have residual cancer in the excised specimens.

Adult↗
PubMed1991

Effect of smoking cessation on serum apolipoprotein A-I and A-II concentrations.

This study investigated the effects of 6 weeks' smoking cessation on serum levels of total-cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C) and apolipoproteins A-I and A-II (apo A-I and apo A-II) in 64 subjects of both sexes. Smoking cessation was associated with an increase in levels of apo A-II. Concurrent changes in weight and alcohol consumption during attempted smoking cessation, together with change in thiocyanate level, were entered as predictor variables into a multiple regression analysis. The change in apo A-II was found to be best accounted for by change in plasma thiocyanate level, and, in women, change in HDL-C and apo A-I by change in weight. The changes induced by smoking cessation may be due, at least in part, to associated changes in alcohol consumption and/or dietary intake, but in the case of apo A-II there is evidence of a more direct effect.

Adult↗
PubMed1989

Apolipoprotein A-I and A-II levels in an Australian population.

Values for apolipoproteins A-I and A-II (apo A-I and apo A-II) are reported for 389 women and 390 men in the town of Busselton, Western Australia. Apo A-I levels were found to be relatively constant with age in men but to rise with age in women. Apo A-II levels remained constant with age in men until older age, when they declined, but rose with age in women, showing a fall in the oldest age group. Apo A-I levels were greater in women than in men, but apo A-II levels were lower in younger women than in younger men, and higher in older women than in older men. On stepwise multiple regression analysis, neither apo A-I nor apo A-II levels showed an independent relationship with age in women; the same was true for apo A-I in men. Alcohol consumption was directly associated with apo A-I and A-II levels in both sexes; adiposity was inversely associated with apo A-I levels in both sexes but with apo A-II only in women. Triglyceride levels showed an inverse association with apo A-II in women. Frequency of exercise was independently and directly associated with apo A-I and A-II levels in women only.

Adolescent↗