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Biomedical subjects

J G Noble

Publications and source records attributed to J G Noble.

At least 19 recordsLinked to original sources
PubMed2004

Melatonin pharmacotherapy for nocturia in men with benign prostatic enlargement.

PURPOSE: Nocturia is a common condition often attributed in aging men to benign prostatic enlargement. Older adults are prone to nocturnal sleep disturbance, of which disturbed circadian rhythm may be a component since it improves with nighttime administration of melatonin. This study was designed to investigate melatonin as a potential treatment for nocturia associated with bladder outflow obstruction in older men. MATERIALS AND METHODS: A total of 20 men with urodynamically confirmed bladder outflow obstruction and nocturia were entered into a randomized, double blind, placebo controlled crossover study assessing the effect of 2 mg controlled release melatonin at night on nocturia. Symptoms were assessed at baseline and after each 4-week treatment period using a frequency volume chart, the International Prostate Symptom Score and symptom problem index. Maximum urinary flow rate and post-void residual urine volume were also assessed. RESULTS: Baseline frequency of nocturia was 3.1 episodes per night. There were 7 men (35%) with detrusor overactivity and 10 (50%) had nocturnal polyuria. Melatonin and placebo caused a decrease in nocturia of 0.32 and 0.05 episodes per night (p = 0.07) and a decrease in the nocturia bother score of 0.51 and 0.05, respectively (p = 0.008). Nocturia responder rates (a reduction from baseline of at least -0.5 episodes per night) differed between the active medication and placebo groups (p = 0.04). Daytime urinary frequency, International Prostate Symptom Score, relative nocturnal urine volume, maximum urinary flow rate and post-void residual were unaffected by melatonin treatment. CONCLUSIONS: Melatonin treatment is associated with a significant nocturia response rate, improvement in nocturia related bother and a good adverse effect profile. However, it is uncertain whether the observed changes in this study are clinically significant.

Aged↗
PubMed2002

Interferential therapy: lack of effect upon experimentally induced delayed onset muscle soreness.

This study was designed to assess the analgesic effects of interferential therapy (IFT) on experimentally induced muscular pain under randomized, double-blind, placebo-controlled conditions. After ethical approval and written consent were obtained, 40 healthy human volunteers (20 males: 20 females) aged 18-25 years were recruited and randomly assigned to one of four experimental groups (n = 10 per group: male = female): IFT 1, IFT 2, control or placebo. Delayed onset muscle soreness (DOMS) was induced in the elbow flexors of the non-dominant arm of each subject using a single bout of eccentric exercises to exhaustion. Measurements of isometric peak torque, resting angle, mechanical pain threshold and visual analogue scales were performed at set time points. Treatment was applied for 30 min daily over the biceps brachii muscle, for five consecutive days, according to group allocation. IFT 1 received 10-20 Hz, whilst subjects in IFT 2 were treated with 80-100 Hz (bi-pole; carrier frequency: 4 kHz; pulse duration: 125 microseconds). For the placebo group, the procedure was identical to that in the active treatment groups; however, no interferential current was delivered. The control group received no treatment. No significant between group difference was identified at any time point (P > or = 0.14). However, some inconsistent, yet significant differences in daily treatment effects, interactive effects and effects over time were detected. Based on the results of this study it can be concluded that application of IFT at the parameters used here, had no overall beneficial effect on DOMS.

Adolescent↗
PubMed2001

The effect of three electrotherapeutic modalities upon peripheral nerve conduction and mechanical pain threshold.

The current study was designed to examine the neurophysiological and hypoalgesic effects of three types of electrical stimulation. Following approval by the University's Research Ethical Committee, healthy volunteers (n=40; 20 males and 20 females; age 20-40 years; mean age 26.18 years) were recruited and screened for contraindications. Subjects were randomly allocated in equal numbers to the following groups: control, transcutaneous electrical nerve stimulation (TENS; 150 Hz, 125 micros), interferential therapy (IFT; 150 Hz, 125 micros) or action potential stimulation therapy (APS; 153 Hz, 6.4 ms). All treatments were applied under double-blind conditions for 15 min over the course of the median nerve in the subject's right forearm. Antidromic median nerve compound action potentials (CAPs) were recorded pretreatment, immediately post-treatment (i.e. at 15 min) and then at 25, 35 and 45 min. Immediately following CAP recording, mechanical pain threshold (MPT) was recorded from two sites on the palmar surface of the right hand. Statistical analysis showed significant differences between groups for peak to peak amplitude (PPA) at 25, 35 and 45 min (Kruskal-Wallis: P=0.01, 0.01 and 0.02). Mann-Whitney U-tests indicated a significant increase in PPA in the IFT group compared with all other groups at 25 and 35 min and compared with the TENS and APS groups at 45 min. No significant differences were found for the MPT data. This study has therefore demonstrated that none of the aforementioned modalities produced a significant hypoalgesic effect; however, IFT produced a significant change in PPA compared with TENS and APS.

Action Potentials↗
PubMed2001

Monochromatic infrared irradiation (890 nm): effect of a multisource array upon conduction in the human median nerve.

OBJECTIVE: Antidromic conduction studies in the human median nerve were used to assess the neurophysiological effects of irradiation of the skin overlying the nerve using a novel treatment unit comprising a multisource monochromatic infrared diode array (Equilight, Denver, CO). MATERIALS AND METHODS: Healthy human volunteers (n = 40) were recruited and randomly allocated to one of four groups: control, placebo, or one of two treatment groups (1.7 and 4.0 J/cm2). After baseline recordings of negative peak latency (NPL) were completed on the nondominant arm, subjects were treated according to group allocation. Recordings were subsequently repeated at 5-min intervals over a 45-min period. RESULTS: Analysis of negative peak latency difference scores (ANOVA) demonstrated significant differences in NPL between groups and over time (p < 0.05). While in the control and placebo groups NPL values remained relatively stable, in the two treatment groups such values decreased marginally, with the greatest effects observed in the 4.0 J/cm2 group (e.g., at 5 min, differences in NPL [mean +/- SEM]: control group, 0.02+/-0.03 msec; treatment group 2, 4 J/cm2, -0.07+/-0.03 msec). Similar significant differences were observed in skin temperature; correlation analysis indicated a weak (but expected) positive linear relationship between skin temperature and nerve conduction velocity (r = 0.125). CONCLUSION: These results suggest that irradiation at the parameters and under the conditions used here produce a direct neurophysiological effect. The magnitude of such effects are in keeping with previous findings using single source arrays at higher radiant exposures or thermal effects of the treatment unit.

Adult↗
PubMed2001

Haematuria: a long-term problem after prostatectomy.

OBJECTIVE: The causes of 'late' haematuria (2 years or more) following endoscopic and open prostatectomy were studied. METHODS: Between 1994 and 1996, more than 400 patients were evaluated for haematuria. Ninety patients with post-prostatectomy haematuria were investigated with upper tract imaging and cystoscopic examination. Amongst these 90 patients, 30 presented with haematuria within 2 years of surgery. These patients were excluded from the study as they had normal investigations. RESULTS: Of these 60 patients, 24 (43%) had demonstrable causes of haematuria in their urinary tract. Six of them had urinary tract malignancy. CONCLUSIONS: There is a substantial likelihood of finding a cause for haematuria in patients who had prostatectomy even though they had full-scale urological investigations before. There is a need, therefore, to carry out necessary screening investigations in such patients.

Aged↗
PubMed2001

Transcutaneous electrical nerve stimulation (TENS): the effect of electrode placement upon cutaneous blood flow and skin temperature.

In the current study the effect of electrode placement on cutaneous blood flow and skin temperature were assessed using laser Doppler flowmetry. Following approval from the University's ethical committee, 30 subjects were recruited (15 male: 15 female) and randomly assigned to a control or one of two treatment groups (n=10 all groups). TENS was applied either over the median nerve or to the Hegyu acupuncture point (L.I.4) for 15 minutes. Blood flow and skin temperature data were recorded during TENS and for 15 minutes post TENS. Analysis of results showed significant differences between groups for cutaneous blood flow (p=0.0001; repeated measures ANOVA). There was a significant increase in blood flow in the TENS median nerve group compared with the other two groups during TENS application. No significant changes in skin temperature were observed between groups. This study demonstrates that the effect of TENS upon cutaneous blood flow is dependent upon electrode placement sites.

Acupuncture Points↗
PubMed2000

Studies of the pathophysiology of idiopathic detrusor instability: the physiological properties of the detrusor smooth muscle and its pattern of innervation.

PURPOSE: Idiopathic detrusor instability (IDI) is a common cause of lower urinary tract storage symptoms, such as urgency, frequency and urge incontinence. We have investigated the in vitro properties and pattern of innervation of the detrusor from patients with this condition. MATERIALS AND METHODS: Full thickness bladder specimens were obtained perioperatively from 14 patients with IDI and from 14 cadaveric controls undergoing transplant organ retrieval. Isolated detrusor smooth muscle strips were mounted in organ baths for isometric tension recording. Frequency-response curves to electrical field stimulation (EFS) (1 Hz to 50 Hz) and concentration response curves for carbachol (10(-7) M to 5 x 10(-4) M) and potassium (12 mM to 120 mM) were constructed. Acetylcholinesterase histochemistry and immunohistochemistry for both phosphorylated and non-phosphorylated neurofilaments was carried out on frozen sections of control and IDI bladders. RESULTS: IDI strips developed greater spontaneous tone (0.25 gm./mg. versus 0.12 gm./mg.; p <0.0001) and more spontaneous fused tetanic contractions (16.8% versus 6.8%; p <0.005) during an initial 90 minutes equilibration period. The IDI strips were less responsive than controls to nerve stimulation (max. response to EFS 0.79 gm./mg. versus 1.23 gm./mg.; p <0.0001) and were supersensitive to potassium (EC50 39.7 mM versus 45.7 mM; p = 0.003) but not to carbachol (EC50 7.3 x 10(-6) M versus 6.6 x 10(-6) M; p = 0.48). Morphometric studies revealed reduced staining of presumed cholinergic nerves, with 34.7% of IDI smooth muscle bundles appearing denervated compared with 1.5% of controls (p <0.0001). CONCLUSIONS: Our study supports the notion that there is a fundamental abnormality in IDI at the level of the bladder wall, with evidence of altered spontaneous contractile activity consistent with an increased electrical coupling of cells, a patchy denervation of the detrusor and a potassium supersensitivity.

Adult↗
PubMed2000

The effect of interferential therapy upon cutaneous blood flow in humans.

The aim of the current controlled and blinded study was to investigate the effect of various interferential current frequencies upon cutaneous blood flow in humans using laser Doppler flowmetry, in an attempt to define the physiological mechanisms involved. Following approval from the university's ethical committee, 50 healthy volunteers (25 male, 25 female; age 18-34 years) were randomly allocated into one of five experimental groups: (i) control; neither suction nor interferential current was applied, (ii) placebo; suction only was applied, (iii) IFT 1; 10-100 Hz beat frequency applied, (iv) IFT 2; 80-100 Hz beat frequency applied, and (v) IFT 3; 10-20 Hz beat frequency applied. In the IFT groups, interferential currents were applied through four suction electrodes positioned to target the quadriceps femoris muscle. The following parameters were used in all IFT groups: 125 micros pulse duration, 4 kHz carrier frequency and a 6/6 sweep. In IFT groups 1 and 2 only, the rotating vector system was made active. Ambient and skin temperatures were measured concomitantly. Repeated-measures ANOVA showed a significant difference between groups (P=0.0361) and over time (P=0.0001) for blood flow data; one-factor ANOVA showed a significant increase in blood flow in the IFT 3 group (10-20 Hz) when compared to all experimental groups at 12 min (P=0.0156). In addition, at 21 min, there were significant differences between the IFT 3 group and all other groups except control (P=0.0213). Statistical analysis of skin temperature data demonstrated significant differences over time (P=0.0001) and a significant interactive effect (P=0.0022), with no significant differences observed between groups. These findings provide some evidence of a putative vasodilatory effect caused by interferential current therapy when applied through suction electrodes at a modulated frequency of 10-20 Hz.

Adolescent↗
PubMed2000

The contribution of cholinergic detrusor excitation in a pig model of bladder hypocompliance.

OBJECTIVE: To investigate the role of cholinergic excitation in mediating changes in detrusor compliance (manifested on conventional cystometry as an incremental rise in detrusor pressure as bladder volume increases) under conditions of propofol-sedation in the pig. Materials and methods Consecutive cystometrograms (CMGs) were obtained from eight female Large White pigs at a bladder filling rate of 50 mL/min. The first CMG was obtained while the pig was awake and unsedated. Two subsequent CMGs were obtained after light to moderate sedation with propofol (2-8 mg/kg/h) before and after the administration of intravenous atropine (0.02 mg/kg). RESULTS: All bladders were highly compliant over the volumes instilled (before sedation) with a maximum pressure during the filling phase of 0.9 cmH2O and a compliance of 943 mL/cmH2O. After sedation with propofol, the maximum pressure during the filling phase increased to 14 cmH2O with a compliance of 69 mL/cmH2O. Atropine antagonized this change in compliance; after sedation and atropine, the maximum pressure during the filling phase decreased to 4 cmH2O (P < 0.05) and the compliance increased to 337 mL/cmH2O (P < 0.05). CONCLUSION: The decrease in compliance seen in the pig bladder after sedation with propofol is mediated via muscarinic excitation. This probably occurs as a result of low-level tonic release of acetylcholine by the efferent parasympathetic nerves. The existence of such efferent excitatory activity during the storage phase in the overactive human bladder might explain the efficacy of bladder-selective muscarinic antagonists in a proportion of patients with detrusor hyper-reflexia and instability.

Animals↗
PubMed2000

Radiotelemetered cystometry in pigs: validation and comparison of natural filling versus diuresis cystometry.

PURPOSE: Cystometry has previously been performed in awake animals using vesical and abdominal catheters, and artificial bladder filling. Conventional urodynamic recordings may be obtained in this manner, albeit under nonphysiological and potentially stressful conditions. Therefore, we developed a technique to perform continuous, ambulatory cystometric monitoring in pigs. MATERIALS AND METHODS: A dual pressure radiotelemetry device was surgically implanted in 22 large white pigs. Vesical and abdominal pressures were recorded and validated, subtracted detrusor pressures were derived and natural fill and diuresis cystometry was compared. RESULTS: Continuous recordings were obtained for 1 to 24 hours, and the devices remained in the animals for up to 3 months. There were few complications and incrustation of the intravesical catheter tip occurred but it did not appear to affect recorded pressures. The pressure data were validated by comparison with filling pressures during bladder distention and simultaneous conventional cystometry at the end of the experimental period. Comparison of natural filling and diuresis cystometrograms showed that natural bladder filling results in higher maximum detrusor pressure during voiding (38.1 versus 33.9 cm. H2O, p <0.05), higher detrusor pressure after contractions (42.6 versus 32.2 cm. H2O, p <0.05) and more frequent detection of unstable contractions in pigs with detrusor instability secondary to experimental manipulation of the lower urinary tract (77.8% versus 45.0%, p <0.05). CONCLUSIONS: This technique allows continuous cystometric monitoring in less stressed animals under more physiological conditions for relatively long periods and, thus, allows prolonged assessment of bladder function in pigs in response to pathological and pharmacological manipulations. Nonphysiological rates of bladder filling have been shown to result in detrusor inhibition, which emphasizes the importance of ambulatory cystometry when describing bladder function.

Animals↗
PubMed1999

Co-localization of carbon monoxide and nitric oxide synthesizing enzymes in the human urethral sphincter.

PURPOSE: Ineffective relaxation of the urethral sphincter during micturition can result in obstructive voiding symptoms. Several studies suggest carbon monoxide (CO) acts alongside nitric oxide (NO) as an inhibitory neurotransmitter, and may regulate NO production. We have investigated the distribution of the constitutive CO producing enzyme, heme oxygenase-2 (HO-2) and the NO producing enzyme, neuronal nitric oxide synthase (nNOS), in the human urethra. MATERIALS AND METHODS: Transverse cryostat sections (12 microns.) were cut from three male membranous and six female urethrae. Double immunofluorescence was carried out for co-localization of HO-2 with nNOS using standard methodology. RESULTS: Nerve trunks showing both HO-2 and nNOS immunoreactivities were identified in the urethrae in both sexes. In the female urethrae, of 152 ganglionic cell bodies expressing HO-2 or nNOS immunoreactivity, 74.3% exhibited both HO-2 and nNOS immunoreactivities, 25% exhibited only HO-2 immunoreactivity and 0.7% exhibited only nNOS immunoreactivity. CONCLUSIONS: Immunoreactivity for HO-2 has been demonstrated in neuronal structures innervating the male and female urethral sphincters. The dual expression of HO-2 with nNOS immunoreactivity in cell bodies and nerves suggests that there is an interaction between the CO and NO generating systems. Abnormality in these systems may play a role in urethral dysfunction.

Carbon Monoxide↗
PubMed1998

Ureteric trauma in gynecologic surgery.

Nearly all gynecological procedures have been reported to cause ureteric injury, with an incidence of 0.4%-2.5% for non-malignant conditions. The incidence is rising as more ambitious operations are undertaken laparoscopically. Risk factors for ureteric injury include cancer, hemorrhage, endometriosis, adhesions and an enlarged uterus. Types of injury include ligation, crush, laceration, avulsion, stretch and devascularization. The diagnosis may be obvious intraoperatively, but postoperative presentation with loin pain, pyrexia, fistula or non-specific signs is more common. A significant number are asymptomatic. Early diagnosis is vital, and urological investigation should be considered in any patient who is not recovering as expected. Injuries recognized intraoperatively should be repaired during the same operation. Delayed recognized injuries are being managed conservatively with increasing success in selected cases. Early operative repair achieves good results unless the injury is severe. Litigation is less likely if the diagnosis is prompt, repair is successful and the patient is treated with consideration.

Female↗
PubMed1998

Nitric oxide synthase in the heterogeneous population of intramural striated muscle fibres of the human membranous urethral sphincter.

PURPOSE: Nitric oxide (NO) is known to relax urethral smooth muscle. The role of NO in the control of urethral striated muscle remains unknown. We have investigated the distribution of nitric oxide synthase (NOS) immunoreactivity and its possible relationship with subtypes of intramural striated muscle fibers in the human male membranous urethra. MATERIALS AND METHODS: Whole transverse cryostat sections from seven membranous urethrae were studied using NOS immunohistochemistry and NADPH diaphorase histochemistry. Striated fiber subtypes were demonstrated using immunohistochemistry for troponin T and histochemistry for myofibrillary adenosine triphosphatase (ATPase). Consecutive sections were used to assess the correlation between the distribution of NOS immunoreactivity and the type of striated fibers. RESULTS: NOS immunoreactivity and NADPH diaphorase activity were detected in the sarcolemma of 48.5% of the intramural striated muscle fibers. NOS immunoreactive nerve trunks and fine nerve fibers, a few of which appeared to end on muscle fibers, were present in the striated sphincter. Fast twitch fibers were detected by ATPase staining, and also exhibited positive immunoreactivity for troponin T, constituting 34.6% of the total number of striated fibers. Two populations of slow twitch fibers were identified; one with small diameter (mean: 15.7 microns) and another of larger diameter (mean: 21.7 microns) comparable to that of fast twitch fibers. 86% of the fast twitch fibers and 29% of slow twitch fibers (most of which had larger diameters) exhibited NOS immunoreactivity and NADPH diaphorase activity in the sarcolemma. CONCLUSIONS: The presence of nitrergic nerve fibers in the striated urethral sphincter suggests an involvement in the innervation of urethral striated muscle. Furthermore, the presence of NOS immunoreactivity in the sarcolemma may indicate a role for NO in the regulation of urethral striated muscle metabolism and contraction.

Adolescent↗
PubMed1995

Urethral sphincter volumes in women with obstructed voiding and abnormal sphincter electromyographic activity.

OBJECTIVE: To investigate the role of transrectal ultrasonography (TRUS) of the female urethral sphincter and to compare sphincter volumes in controls and women with obstructed voiding associated with abnormal myotonic-like electromyographic (EMG) activity in the urethral sphincter. PATIENTS AND METHODS: Fourteen women patients (mean age 29 +/- 3.2 years) with symptoms of urinary outlet obstruction underwent videocystometrography (VCMG), urethral sphincter EMG and TRUS. Their sphincter volumes were compared with those obtained from 20 age-matched control patients with other urodynamic diagnoses or normal urodynamics. RESULTS: In every patient the urethral sphincter was identified as an ovoid, hypoechoic structure distal to the bladder outlet. The mean volume of the sphincter in those patients with abnormal EMG activity (3.05 +/- 0.23 cm3) was significantly greater than that in the control group (1.30 +/- 0.09 cm3; P < 0.001). CONCLUSION: TRUS provided a useful method of imaging the urethral sphincter in women. The results suggest that there was an increase in the volume of the urethral sphincter in females with obstructed voiding, providing collateral evidence that the abnormal EMG activity is a significant factor in the pathophysiology of the disorder.

Adult↗
PubMed1994

Renal adenocarcinoma in young adults.

Renal adenocarcinoma is rare in young people. The prognosis of the condition would appear to be better in young people justifying a radical treatment rationale even in cases of advanced disease. This report describes a series of patients under the age of 30 with renal adenocarcinoma and a review of the literature. The possible mechanisms for the apparent improved survival of patients in this age group is discussed.

Adenocarcinoma↗
PubMed1993

Comparative study of selective alpha 1-adrenoceptor blockade versus surgery in the treatment of prostatic obstruction.

Alternative treatments for benign prostatic hyperplasia (BPH) are the source of much discussion at present. Pharmacotherapy has been demonstrated to have an increasing role in the management of BPH. This study contrasts the efficacy of the selective alpha antagonist prazosin as compared with placebo and the subsequent improvements seen following surgical treatment. Whilst selective alpha blockade has undoubted therapeutic efficacy the improvement in symptom scores and the objective urodynamic measure of the flow rate are not as marked as those seen following surgery.

Aged↗