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Biomedical subjects

N J Parr

Publications and source records attributed to N J Parr.

At least 19 recordsLinked to original sources
PubMed2003

Immediate dual energy X-ray absorptiometry reveals a high incidence of osteoporosis in patients with advanced prostate cancer before hormonal manipulation.

OBJECTIVE: To examine the incidence of osteoporosis in patients with advanced prostate cancer (using forearm densitometry) before commencing androgen deprivation therapy (ADT), as osteoporotic fractures are more frequent in patients with prostate cancer who have undergone either medical or surgical castration, because of rapid loss of bone mass. PATIENTS AND METHODS: In all, 174 patients (mean age 74.6 years, range 46-90) with advanced prostate cancer presented over 2 years. Their forearm bone densitometry values were compared with those from 106 age-matched controls (mean age 74.3 years, range 66-90). RESULTS: Of the 174 patients, 73 (42%) were osteoporotic (t score <or=- 2.5) and 65 (37%) were osteopenic (t score - 1 to - 2.4). This compares with a 27% incidence of osteoporosis in the control group (P = 0.022). There were also no significant correlations between prostate specific antigen levels, Gleason score, tumour stage, biochemical markers and the presence or absence of osteoporosis risk factors. CONCLUSION: Patients with advanced prostate cancer requiring ADT have a high incidence of osteoporosis before treatment. In addition, osteoporosis in these men cannot be predicted from clinical or biochemical values. Therefore, bone densitometry should be used in all patients with advanced cancer requiring ADT, as the results have implications for the choice of cancer therapy and the prophylaxis for osteoporosis.

Absorptiometry, Photon↗
PubMed2001

Single bead characterization using analytical constructs: application to quality control of libraries.

Analytical construct technology has been successfully applied to the single-bead analysis of a split-mix combinatorial library. Substrates can be released from the resin by conventional cleavage for biological screening. Alternatively, for the purpose of analysis and quality control, cleavage at an orthogonal construct linker produces an analytical fragment incorporating the substrate. This analytical fragmnent is highly sensitized to electrospray mass spectrometry (ESI-MS) and is easily identified by isotope labeling. The construct cleavage rendered readily visible even those compounds that clearly could not be seen by conventional cleavage and mass spectrometry analysis. A 1H NMR control experiment proved that the compounds cleaved conventionally were, however, present in the sample in good yield and purity. In view of the data obtained, we think that this is a significant and important step toward solving our current quality control problems.

Amino Acids↗
PubMed2000

The effect of fasting or desmopressin before treatment on the concentration of mitomycin C during intravesical administration.

OBJECTIVE: To evaluate two methods of reducing the urine output during treatment (the most easily manipulated variable) in patients undergoing intravesical instillation with mitomycin C, where the concentration-time curve also depends upon dose, diluent volume, residual urine volume, and drug absorption and degradation. PATIENTS AND METHODS: The study comprised 20 consecutive patients undergoing a course of six weekly instillations of mitomycin C (40 mg in 40 mL for 1 h) for superficial bladder carcinoma. Urine production during treatment was calculated by adding the voided volume and ultrasonographically measured residual urine after treatment, and subtracting 40 mL; the patient's bladder was emptied before instillation. Before the first and second visit the patients were asked to drink normally. Before the third and fourth visit patients fasted for 6 h before treatment. For the fifth and sixth visit the patients had not fasted, but 200 microg of desmopressin was given orally 1 h before instillation. Any urinary side-effects were graded on a four-point scale. RESULTS: There were 17 patients with complete data; one patient failed to take desmopressin, one had detrusor instability and one developed chemical cystitis. The mean (SD) urine production in unprepared patients was 209 (123) mL, which decreased to 143 (80) mL (P = 0.039, t-test) after fasting and 103 (51) mL (P < 0.001) with desmopressin. This equates to a 20% increase in mean intravesical drug concentration with fasting and a 38% increase with desmopressin. Urinary side-effects were graded as mild in each group. CONCLUSION: Unprepared patients produce variable and often substantial volumes of urine during intravesical chemotherapy. There was a significant reduction in urine output after fasting or by administering desmopressin before instillation. These measures increase the area under the concentration-time curve for mitomycin C and potentially increase the efficacy of treatment.

Administration, Intravesical↗
PubMed1995

Pre-marital fertility in Liberia.

This analysis of the 1986 Liberia Demographic and Health Survey data finds remarkably high fertility levels among women who have never married or lived with a man, reflecting widespread pre-marital sex and a lack of use of contraception. It is found that single Liberian women are more likely to foster out children than married Liberian women of the same age.

Adolescent↗
PubMed1995

The effect of extracorporeal piezoelectric lithotripsy on the contractility of the human pelvicalyceal system.

OBJECTIVE: To assess the effect of extracorporeal piezoelectric lithotripsy (EPL) on the contractility of the human pelvicalyceal system. PATIENTS AND METHODS: Contractions of the pelvicalyceal system were measured in 12 patients (mean age 55 years) before and after EPL. Pelvicalyceal pressure was measured via a Cope nephrostomy tube which had remained in situ following stone debulking procedures days or weeks earlier. All patients were treated using a Wolf Piezolith 2300 lithotripter. RESULTS: The pelvicalyceal systems of two patients were acontractile before and after treatment. Immediately after treatment, contractions were completely abolished in eight of the remaining 10 systems, and reduced in frequency in the other two. All 10 systems regained contractions 24 h after treatment. CONCLUSION: Piezoelectric lithotripsy temporarily abolishes upper urinary tract motility.

Female↗
PubMed1994

Comparison of the performance of two pulsed dye lasers using a synthetic stone model.

The performance of two pulsed dye laser lithotripters was compared in vitro using a synthetic calculus with gross physical properties similar to natural urinary tract calculi. Synthetic calculi were subjected to 500 shocks at nominal pulse energies of 40, 60, 80, 100 and 120 mJ using a 320 micron. fiber. Three calculi were treated at each energy level on the Technomed Pulsolith and two at each level on the Candela MDL 2000. The pattern of fragmentation was similar with both lithotripters. Increasing the energy level resulted in a linear increase in fragmentation (Pulsolith r = 0.95, MDL 2000 r = 0.99), but fragmentation was greater with the MDL 2000 than with the Pulsolith (6.01 mg/mJ versus 5.00 mg./mJ, p < 0.001). Both lasers fragmented the calculi satisfactorily. We recommend that all users of such lasers acquire a laser meter to allow monitoring of the energy delivered by the fiber tip.

Lithotripsy, Laser↗
PubMed1994

Laparoscopic pelvic lymphadenectomy--early results.

OBJECTIVE: To report our initial experience and early results of laparoscopic pelvic lymphadenectomy (LPL). PATIENTS AND METHODS: Between May 1991 and April 1992, 10 patients with genitourinary malignancy (eight prostate, one bladder carcinoma, one penile melanoma) underwent LPL. Following biopsy, initial staging was carried out using computed tomography (CT), a bone scan and the prostate specific antigen level (prostate cancer). Six patients underwent unilateral laparoscopic dissection, three patients bilateral dissection and one patient required conversion to an open procedure. Operative times ranged from 2 to 3 h, and the number of lymph nodes removed ranged from three to nine (median five). RESULTS: Three patients had their staging altered following LPL (one patient was upstaged and two patients were downstaged), with significant therapeutic implications. Two patients suffered thromboembolic complications while undergoing definitive therapy soon after LPL. CONCLUSION: Our early results suggest that LPL is valuable in identifying suitable patients for radical therapy as well as excluding patients with lymph node involvement, thereby reducing morbidity.

Aged↗
PubMed1993

Catheter valves.

Explore the source record for details and available documents.

Humans↗
PubMed1993

Suppurative epididymo-orchitis in young "high risk" patients--a new problem?

During a 4-year period we have treated 3 young patients with severe epididymo-orchitis which progressed to suppuration (despite treatment with a range of antibiotics) and necessitated orchiectomy. All gave a history of "high risk" activity (2 homosexual, 1 sexual partner of intravenous drug user). One patient was suffering from acquired immune deficiency syndrome and another presented during seroconversion to HIV-positive status. Cytomegalovirus was the infective organism in one patient, but the pathogenesis in the others remains obscure. Investigations for atypical pathogens should be performed when young patients present with refractory epididymo-orchitis. These patients should also be counselled with regard to HIV testing.

AIDS-Related Opportunistic Infections↗