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Biomedical subjects

G Brock

Publications and source records attributed to G Brock.

At least 19 recordsLinked to original sources
PubMed2002

Glutathione in gingival crevicular fluid and its relation to local antioxidant capacity in periodontal health and disease.

AIMS: To determine possible changes in gingival crevicular fluid (GCF) antioxidant defence in chronic adult periodontal disease and to investigate the nature of the local radical scavenging mechanisms, with particular reference to glutathione. METHODS: GCF and plasma were collected from patients with chronic periodontitis and age and sex matched control subjects (n = 10). Polymorphonuclear leucocytes (PMNLs) were prepared and gingival epithelial cells (GECs) were collected by conventional methods from periodontally healthy subjects. PMNL were stimulated with F-Met-Leu-Phe after cytochalasin B treatment. Enhanced chemiluminescence was used to determine the total antioxidant capacity and to investigate the activity of cell fractions and reducing agents. GCF concentrations of reduced (GSH) and oxidised (GSSG) glutathione were determined by high performance liquid chromatography. RESULTS: Plasma and GCF from patients contained lower mean (SD) total antioxidant capacity (501.8 (123) micro M Teq/litre and 658.3 (392) micro M Teq/litre, respectively) compared with controls (577.9 (99.8) and 1351.5 (861) micro M Teq/litre, respectively). Antioxidant light recovery profiles for GCF demonstrated a stepped response, not seen in plasma, which was inhibited by N-ethylmaleimide. This response was also detected in the cytosolic fraction of GEC and anaerobically stimulated PMNL. Similar antioxidant profiles, inhibitable by N-ethylmaleimide, were obtained with cysteamine, cysteine, and GSH. Control GCF contained high mean (SD) concentrations of glutathione (GSH, 1899.8 (494.4) micro M; GSSG, 256.8 (152.4) micro M). GCF from patients with periodontitis contained significantly lower amounts of GSH (mean, 1183.1; SD, 580.3 micro M) and GSSG (mean, 150.1; SD, 44.9 micro M). CONCLUSIONS: GSH values and total antioxidant capacity are reduced in chronic periodontal disease. The high concentrations of GSH present in GCF in health are similar to those found extracellularly in the lung and may represent an important antioxidant and anti-inflammatory defence strategy common to exposed epithelial surfaces.

Adult↗
PubMed2001

Return of spontaneous erection during long-term intracavernosal alprostadil (Caverject) treatment.

OBJECTIVES: To investigate the effect of long-term intracavernosal self-injection of alprostadil (Caverject) on the penile circulation and return of spontaneous erection in men with arteriogenic erectile dysfunction. METHODS: Seventy men with a stable heterosexual partner entered the titration phase of this open-label, flexible-dose study. The effective alprostadil dose (ie, the dose producing penile rigidity adequate for intercourse and lasting up to 60 minutes) was determined before entry into the 12-month self-treatment home phase. Duplex ultrasonography was used to measure the peak systolic velocity and diameter of the cavernosal arteries at the end of the titration phase and after 4, 8, and 12 months of the home phase. The efficacy, tolerability, and return of spontaneous erections were assessed from the patients' diaries and by interview at each clinic visit. Sixty-three men entered the home phase; 49 of them filled out the diaries and 42 completed the study. RESULTS: An effective dose was established for 67 (96%) of the 70 men (median dose 15 microg). During the home phase, 94% of men responded to alprostadil, and the median dose remained unchanged. Complete duplex ultrasound data were obtained in 38 men and showed significant increases in postinjection peak systolic velocity in both cavernosal arteries (P <0.001 at 12 months) and between the preinjection and postinjection cavernosal arterial diameters (P = 0.0001) compared with baseline. Reports of a return of spontaneous erections increased throughout the study compared with baseline (37%, 26 of 70) and were confirmed by interview for 46 (85%) of 54 men with available data overall. Treatment was generally well accepted, with low incidences of penile pain (23%), prolonged erection, which resolved spontaneously (6%), and fibrosis (1%). CONCLUSIONS: Intracavernosal alprostadil was effective, acceptable, and generally well tolerated in men with arteriogenic erectile dysfunction. Long-term treatment improved the penile circulation, and most men reported an increase in return of spontaneous erections.

Adult↗
PubMed2001

Intracavernosal alprostadil is effective for the treatment of erectile dysfunction in diabetic men.

The efficacy and safety of intracavernosal alprostadil was evaluated for the treatment of erectile dysfunction in men with type I or type II diabetes mellitus. This was an open-label, flexible dose-escalating study involving 336 men (77% of whom were Asian/Oriental) enrolled by 15 centres in Australia, Canada and seven countries in Asia. The effective alprostadil dose, ie the dose producing penile rigidity adequate for intercourse and lasting up to 60 min, was established by titration at the clinic prior to entry into the 6 month self-treatment home phase. All men were fully trained in the self-injection technique before entry into the home phase. Efficacy and safety were assessed using patient and partner diaries and by interview at clinic visits during the titration phase and after 1, 3 and 6 months of treatment. An effective home dose was established by titration for 94% of the 336 men (median dose 20 microg, range 2.5-60 microg). Of 278 (83%) men who entered the home phase, 277 men (247 with type II diabetes and 30 with type I diabetes) had evaluable data for alprostadil dosage and clinical response. During the home phase, a satisfactory erectile response was achieved after 99% of injections, and the median alprostadil dose remained unchanged. The initial home dose and clinical response were similar in type I and type II diabetic men. Treatment was generally well tolerated with a low incidence of penile pain (24%) In conclusion, intracavernosal alprostadil was effective and well tolerated in type I and type II diabetic men with erectile dysfunction of mixed aetiology.

Adult↗
PubMed2001

Report of the American Foundation for Urologic Disease (AFUD) Thought Leader Panel for evaluation and treatment of priapism.

PURPOSE: Patients with priapism often develop permanent erectile dysfunction and personal sexual distress. This report is intended to help educate the public by reviewing the varied definitions and classifications of priapism and limited literature reports of pathophysiology, diagnosis and treatment outcomes of priapism. The AUA priapism guidelines committee is responsible for creating consensus as to appropriate individual patient management of priapism by physicians. MATERIALS AND METHODS: A multidisciplinary panel, consisting of 19 thought leaders in priapism, was convened by the Sexual Function Health Council of the American Foundation for Urologic Disease to address pertinent issues concerning the role of the urologist, primary care providers and other health care professionals in the education of the public regarding management of men with priapism. The panel utilized a modified Delphi method and built upon the peer review literature on priapism. RESULTS: The Thought Leader Panel recommended adoption of the definition of priapism as a pathological condition of a penile erection that persists beyond or is unrelated to sexual stimulation. Priapism is stressed to be an important medical condition that requires evaluation and may require emergency management. The classification system is categorized into ischemic and non-ischemic priapism. Essential elements of the ischemic classification are the inclusion of: (i) clinical characteristics of pain and rigidity; (ii) diagnostic characteristics of absence of cavernosal arterial blood flow; (iii) pathophysiological characteristics of a closed compartment syndrome; (iv) a time limit of 4 h prior to emergent medical care; and (v) a description of the potential consequences of delayed treatment. Essential elements of the non-ischemic classification are the inclusion of: (i) clinical characteristics of absence of pain and presence of partial rigidity; (ii) diagnostic and pathophysiological characteristics of unregulated cavernosal arterial inflow; and (iii) the need for evaluation but emphasizing the lack of a medical emergency. The panel recommended adoption of a rational management algorithm for the assessment and treatment of priapism where the cornerstone of initial assessment includes a careful clinical history, a focused physical examination and selected laboratory and/or radiologic tests. The panel recommended that specific criteria and clinical profiles requiring specialist referral should be identified. The panel further recommended that patient (and partner) needs and education concerning priapism should be addressed prior to therapeutic intervention, however only in the case of chronic management or post acute presentation evaluation should this delay intervention. Treatment goals to be discussed include management of the priapism with concomitant prevention of permanent and irreversible erectile dysfunction and associated psychosocial consequences. The panel recommended that when specific therapies for priapism are required, a step-care treatment approach based upon reversibility and invasiveness should be followed. CONCLUSIONS: The Thought Leader Panel calls for research to expand our understanding of the prevalence and diagnosis of priapism and education to create awareness among the public of the potential urgency of this condition. Critical areas to be addressed include the multiple pathophysiologies of priapism as well as multi-institutional trials to objectively assess safety and efficacy in the various treatment modalities.

Humans↗
PubMed2000

Near-patient test for nicotine and its metabolites in saliva to assess smoking habit.

Smoking is a major risk factor for periodontal disease, causing bone and tooth loss. Effective management of many oral conditions requires accurate information about smoking. We describe a disposable, 10-min, near-patient saliva test to monitor cigarette smoking. A plastic device contains the dried reagents to measure nicotine and its metabolites by a colorimetric assay. The device can be used to give a semi-quantitative assessment of tobacco consumption by observing a colour change and comparing it to a reference chart. Alternatively, the test can be quantified by measuring the light absorbance with a colorimeter and determining the concentration of nicotine metabolites by reference to a cotinine standard. This method correlates with reported daily cigarette consumption (r=0.62, P<0.0001) and nicotine yield of cigarettes smoked (r=0.35, P<0.01) and compares favourably with cotinine, as measured independently by radioimmunoassay (r=0.57, P<0.005). The method provides a simple-to-use, inexpensive way of monitoring tobacco consumption in dental surgeries.

Adult↗
PubMed1998

Ureteropelvic urinary extravasation due to iliac artery aneurysm.

We report a case of left-sided hydronephrosis and ureteropelvic urinary extravasation due to a large left iliac artery aneurysm. Urinoma was diagnosed preoperatively by contrast-enhanced computed tomography. The patient was successfully treated by percutaneous nephrostomy and ureteral double J stent placement followed by staged operative repair.

Aged↗
PubMed1997

The anatomy of the tunica albuginea in the normal penis and Peyronie's disease.

PURPOSE: We studied the fine architecture of the tunica albuginea of the penis. MATERIALS AND METHODS: The study included 6 human male cadavers and 10 surgical patients (5 with Peyronie's disease and 5 with normal penile anatomy). RESULTS: The tunica albuginea of the corpora cavernosa is a bi-layered structure with multiple sub layers. Inner layer bundles support and contain the cavernous tissue and are oriented circularly. Radiating from this layer are intracavernous pillars acting as struts, which augment the septum and provide essential support to the erectile tissue. Outer layer bundles are oriented longitudinally. These fibers extend from the glans penis to the proximal crura, where they insert into the inferior pubic ramus. There are no outer layer fibers between the 5 and 7 o'clock positions. Elastic fibers normally form an irregularly latticed network on which collagen fibers rest. In Peyronie's disease the well ordered appearance of the collagen layers is lost: excessive deposits of collagen, disordered elastic fibers and fibrin are found within the region of the plaque. CONCLUSIONS: The normal 3-dimensional structure of the tunica affords great flexibility, rigidity and tissue strength to the penis, which are lost consequent to structural changes in Peyronie's disease.

Humans↗
PubMed1996

The international prostate symptom score: physician versus self-administration in the quantification of symptomatology.

OBJECTIVES: The International Prostate Symptom Score (IPSS), originally known as the American Urological Association Score, is the most commonly used scoring system for the quantification of benign prostatic hyperplasia symptoms. One area that has remained unexplored is the stability of the questionnaire construct between different modes of administration. The objective of this study was to measure differences in IPSS when administered by the physician versus patient self-administration. The impact of order of administration was also examined. METHODS: Sixty-four patients completed two IPSS questionnaires during the same office visit, one self-administered and the other by physician interview. The influence of order of administration was examined by randomly allocating patients to either self-administration or physician-administration first. Total symptom scores (questions 1 to 7) and quality of life scores (question 8) were compared between the two modes of administration. Multivariate analysis of variance was performed to assess the effect of age, medical history (obtained from the IPSS form), order of administration, and physician (A and B) on the observed differences. RESULTS: The distribution of differences was similar between the two orders of administration. Overall, 26 patients had a higher total score with self-administration, 30 with physician-administration, and 8 had identical scores on both. Mean total symptom scores and quality of life assessments by physician- versus patient-administered questionnaires were similar (10.9 versus 10.4 and 1.8 versus 2.2, respectively). No statistically significant difference was observed. The order of administration did not show statistical significance (P > 0.05) by multivariate analysis. As well, no interaction was seen between the aforementioned variables. CONCLUSIONS: There is no difference in the information obtained if patients self-administer the questionnaire as opposed to physician administration.

Aged↗
PubMed1995

Rural health care.

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Attitude of Health Personnel↗
PubMed1995

The feisty family.

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Adenocarcinoma↗
PubMed1994

Cloning and expression of cyclosporin A- and FK506-sensitive nuclear factor of activated T-cells: NF45 and NF90.

Nuclear Factor of Activated T-cells (NF-AT) is a crucial transcription factor required for T-cell expression of interleukin 2. Purified NF-AT contains 45-kDa and 90-kDa subunits (Corthésy, B., and Kao, P. N. (1994) J. Biol. Chem. 269, 20682-20690). Partial internal amino acid sequences derived from each subunit indicate that these proteins are novel. The amino acid sequences were used to clone the cDNAs encoding each subunit. The cDNAs predict proteins of novel structures: NF45 has limited similarity to prokaryotic transcription factor sigma-54 and to human DNA topoisomerase II; NF90 has limited similarity to Drosophila Staufen in a domain predicted to bind double-stranded RNA. RNA encoding NF45 and NF90 exists in nonstimulated Jurkat T-cells and in all other cell types examined (HeLa, HepG2, K562). Immunofluorescence microscopy was used to demonstrate that both proteins are located in the nucleus of Jurkat T-cells. Clones NF45 and NF90 with a polyhistidine fusion tag were transiently expressed and processed in the native environment of Jurkat T-cells. Histidine-tagged NF45 and NF90 proteins, affinity-purified on nickel chelate columns, encode a NF-AT DNA-binding activity that is enhanced following T-cell stimulation, and this enhancement is blocked when T-cells are stimulated in the presence of cyclosporin A or FK506.

Amino Acid Sequence↗
PubMed1994

Anatomy and strength of the tunica albuginea: its relevance to penile prosthesis extrusion.

In 7 male cadavers the anatomical structure, thickness and tensile strength of the tunica albuginea of the penis, measured at specific locations, were determined. The tunica is composed of inner circular and outer longitudinal layers made up of collagen bundles. The outer layer appears to determine, to a large extent, the variation in thickness and strength of the tunica. The ventral groove (found between the 5 and 7 o'clock positions), which houses the corpus spongiosum, lacks outer bundles and appears vulnerable to perforation. The thickness of the tunica measured at the 7, 9 and 11 o'clock positions was 0.8 +/- 0.1 mm, 1.2 +/- 0.2 mm and 2.2 +/- 0.4 mm, respectively. Differences in the thickness of the tunica at specific locations were statistically significant (all p < or = 0.018). Symmetrical measurements were nearly identical in a mirror image arrangement (3, 5 and 1 at the 9, 7 and 11 o'clock positions, respectively). The stress on the tunica at penetration (breaking point pressure) measured at the 7, 9 and 11 o'clock positions was 1.6 +/- 0.2 x 10(7) N/m.2, 3.0 +/- 0.3 x 10(7) N/m2 and 4.5 +/- 0.5 x 10(7) N/m.2, respectively. The strength and thickness of the tunica correlated in a statistically significant manner with location (r = 0.911 and p = 0.0001). The most vulnerable area is on the ventral aspect (which lacks the longitudinally directed outer layer bundles), where most prostheses tend to extrude. This finding supports our belief that prosthesis extrusion often has an anatomical basis and is not merely a phenomenon caused by infection or compression.

Biomechanical Phenomena↗
PubMed1994

The distribution of elastic fibrous elements within the human penis.

OBJECTIVE: To determine the distribution of elastic fibres in the tunica albuginea and the erectile tissue of the penis. MATERIALS AND METHODS: Samples of tunica albuginea or penile erectile tissue were taken from seven cadavers and five patients undergoing surgery. Light and electron microscopy were performed. RESULTS: There were two anatomical regions in which elastic fibres were seen rarely: the proximal crus and the distal tunica. In the rest of the corpora cavernosa where the tunica was more compliant, the elastic fibres were in relative abundance. In the corpus spongiosum, abundant irregularly oriented elastic fibres were present; the densest elastic network was found in the glans penis and was composed of coarse elastic fibres. A perisinusoidal fibroelastic shell was seen in the glans, which was probably an extension of Buck's fascia. The elastic components within the sinusoids (cavernosal, spongiosal, and glanular) were similar but finer than the elastic lamellae in the penile arterial wall. CONCLUSION: The elastic fibres were unevenly distributed, often forming an irregular network on which the collagen component rested. Elastic fibres were more abundant in the corpus spongiosum, around the blood vessels and surrounding the sinusoid of the corpus cavernosum.

Collagen↗
PubMed1994

Rat model for the study of penile erection: pharmacologic and electrical-stimulation parameters.

We report the use of a modified rat model for the study of the mechanisms of penile erection. In 92 Sprague-Dawley rats, the cavernous nerve was stimulated with different pulse intensities and frequencies, and the intracavernous pressure, time to maximal pressure and total duration of tumescence were measured. A maximal response was elicited at 20 pulses per second (pps) and 1.5 mA. Using this as 100%, we determined the relative pressure responses obtained with other frequencies: 5 pps, 57.3% (p = 0.007), 10 pps, 84.9% (p = 0.043); 30 pps, 99.5% (p = 0.832); 40 pps, 97.8% (p = 0.168); 50 pps, 90.9% (p = 0.021); 100 pps, 76.1% (p < 0.001). The time to maximal pressure varied with different frequencies, but was in all cases significantly different from the 20-pps response. Erection time during continuous cavernous nerve stimulation was significantly longer with frequencies below 20 pps (10 and 5 pps). In 30 rats, the physiologic response to intracavernous injection (0.03 ml) of acetylcholine, atropine, guanethidine, norepinephrine, phenylephrine, papaverine, terbutaline (intravenous also) and phentolamine was measured. Papaverine caused a dose-dependent rise in pressure; acetylcholine, atropine (a parasympathetic blocking agent) and guanethidine all had minimal effects. Phentolamine and norepinephrine increased systemic blood pressure, whereas phenylephrine decreased the intracavernous pressure in response to electrostimulation significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗