PEGylation of cyanovirin-N, an entry inhibitor of HIV.

Cyanovirin-N (CV-N) is a potent inhibitor of human immunodeficiency virus and many other viruses. It has a high potential for use as a systemic compound to control viral load or in the development of microbicides to prevent primary viral infection. Due to its cyanobacterial origin it is likely to show the typical drawbacks associated with pharmaceutical use of foreign proteins such as short plasma half-life, proteolysis and immunogenicity. Several strategies were used to covalently bond poly(ethylene glycol) (PEGylate) to CV-N. Random PEGylation at lysine residues resulted in poor retention of antiviral activity. Many site-directed mutants were made to test site-specific PEGylation. One mutant, where glutamine 62 was replaced with cysteine (CV-N(Q62C)) and PEGylated with maleimide activated PEG, retained significant anti-HIV activity in vitro.

Procoagulant properties of benign and malignant prostatic tissue.

OBJECTIVE: To determine the factor-X activating procoagulant activity (FXAA) of prostatic tissue removed at transurethral resection in a specific chromogenic assay. PATIENTS AND METHODS: FXAA was extracted from transurethrally resected prostatic tissue using a cryofragmentation technique. Tissue from 50 patients with prostate cancer was analysed and compared with that from 36 control patients with benign prostatic-hypertrophy. Enzyme activities were assayed in a two stage chromogenic assay and correlated with conventional markers of tumour aggressiveness. RESULTS: FXAA was found to be significantly lower (P < 0.001) in tissue from malignant prostates compared with benign prostatic hypertrophy tissue. Loss of FXAA was also related to Gleason grade (P < 0.03), percentage of chips involved by tumour (P < 0.04) and bone scan status (P < 0.02). Using antibody inhibition tests this procoagulant was characterized as being a factor VII/tissue factor complex. CONCLUSIONS: Malignant change in the prostate is associated with a reduction in FXAA and this may be an important factor in prostatic tumour growth and dissemination.

A sham controlled trial of transurethral microwave therapy with subsequent treatment of the control group.

To investigate whether there is a significant placebo component to the improvements seen after 1-session transurethral microwave treatment, 40 patients with significant symptoms of prostatism and unequivocally benign glands were recruited to take part in a sham controlled study. After an active treatment the mean American Urological Association symptom scores improved by 63% (19.2 to 7.1) while after a sham treatment symptom scores improved only marginally (18.8 to 16.2, p < 0.001). Residual volumes decreased by 50% (104 to 52 ml.) and flow rates increased by 2.3 ml. per second after an active treatment with no improvement after a sham treatment. There was a consistently greater improvement after an active treatment compared to a sham treatment. Patients who had received a sham treatment were then offered an active treatment and showed improvements similar to those in the original actively treated group and much greater than after the original sham treatment. Mean symptom scores decreased from 16.2 to 9.9 (p < 0.004). Residual volumes decreased from 94 to 40 ml. (p < 0.005) and flow rates increased by 1.6 ml. per second, while these same criteria had deteriorated after a sham treatment. Side effects were mild and short lived, with no patients reporting sexual dysfunction as a consequence of treatment. Transurethral microwave therapy is an effective well tolerated treatment for select patients with benign prostatic hypertrophy and the placebo effect of treatment is minimal.

99Tcm-DMSA as a dynamic imaging agent for estimating renal blood flow. A comparison with 99Tcm-DTPA.

A technique for estimating fractional renal blood flow (RBF) from the early part of the 99Tcm-diethylenetriaminepentaacetate (DTPA) renogram has been described previously and its reproducibility validated in the pig model. The technique is assumed to be applicable to any recirculating gamma-emitting tracer compound. The aim of this study was to determine whether the same method could be applied to 99Tcm-dimercaptosuccinic acid (DMSA) which has been largely neglected as a dynamic imaging agent. Paired estimates of fractional RBF were obtained in Large White (n = 16) and Göttingen miniature pigs (n = 6) in three groups: group 1, paired 99Tcm-DTPA studies; group 2, paired 99Tcm-DMSA studies; group 3, alternate 99Tcm-DTPA and 99Tcm-DMSA studies. The results showed good agreement between paired results independent of whether 99Tcm-DTPA or 99Tcm-DMSA was used, supporting the assumption that the technique is applicable to any recirculating gamma-emitting tracer compound. The demonstration that fractional RBF can be reliably estimated from the DMSA renogram means that, if required, it may be combined in a single nuclear medicine procedure with conventional static DMSA renal imaging.

The changing conception of mental retardation: implications for the field.

The 1992 American Association on Mental Retardation's (AAMR) definition and classification of mental retardation is different from the previous classification system in that: (a) a single diagnostic code of mental retardation is used if the person meets the three criteria of age of onset (18 or under), significantly subaverage abilities in intellectual functioning, and related limitations in two or more adaptive skills areas; (b) the person's strengths and weaknesses are described in reference to four dimensions: intellectual functioning and adaptive skills; psychological and emotional well-being; health, physical well-being, and etiology; and life activity environments; and (c) a profile of needed supports is developed across the four dimensions. In this article we discussed six major implications of the 1992 System for the field of mental retardation.

Procoagulant activity may be a marker of the malignant phenotype in experimental prostate cancer.

Using a one-stage kinetic chromogenic assay, we studied the procoagulant activity (PCA) of prostatic tissue in an experimental model of prostate cancer in the rat. PCA was present in homogenates of rat prostate glands containing either benign or malignant tumours. The procoagulant activated factor X directly and was provisionally characterised as a tissue factor-factor VIIa complex. There was no significant differences in PCA between control rats and rats exposed to carcinogens that did not develop tumour. Levels in rats that developed tumours were significantly higher (P < 0.01) than all other groups and there was a positive correlation between tumour weight and PCA (r = 0.85, P < 0.001). Furthermore, prostatic PCA levels were higher in the metastasis (P < 0.02). We conclude that PCA reflects the malignant phenotype in this animals, the PCA of the primary tumour was compared with that of the corresponding secondary deposit and levels were higher in the metastasis (P < 0.02). We conclude that PCA reflects the malignant phenotype in this model of experimental prostate cancer and suggest that this parameter is worth evaluating as a potential tumour marker in the human disease.

Transurethral microwave therapy: patient selection and outcome.

Forty-one patients with benign prostatic disease awaiting transurethral resection of the prostate were offered transurethral microwave therapy as an alternative. Pre-operative assessment consisted of symptom scores, prostate-specific antigen levels, flow rates and urinary tract ultrasound with residual urine estimation. Patients were reassessed 6 weeks, 3 months and 6 months after microwave treatment. Twenty-three patients had a successful outcome and 18 an unsuccessful outcome to treatment. Fifteen of the 18 with an unsuccessful outcome could have been predicted by the presence of one or more of the following pretreatment features: glands over 50 g (10 patients), the presence of a median lobe (5 patients), high residual urine (6 patients), a history of recurrent urinary infection (2 patients) and coexisting neurological disorders such as parkinsonism (1 patient) and CVA (1 patient). Three failures had none of these criteria present and could not have been predicted from their pretreatment assessment. Transurethral microwave therapy produces subjective and objective improvements in appropriately selected patients. Patients with large glands or decompensated bladders fail to benefit and should continue to be treated by conventional surgery.

Phase contrast microscopic examination of urinary erythrocytes to localise source of bleeding: an overlooked technique?

AIMS: To localise the source of bleeding in the urinary tract in patients presenting with haematuria. METHODS: Urine samples were obtained from 109 patients with symptoms referable to the urinary tract. The sample was examined for the presence of red blood cells by phase contrast microscopy (PCM) and the proportion of dysmorphic and isomorphic red blood cells was determined. If more than 20% of the red blood cells were dysmorphic a glomerular origin for the site of bleeding was suspected; if less than 20% of the red blood cells were isomorphic a non-glomerular origin was suspected. Phase contrast microscopy and clinical findings were correlated. RESULTS: The correct bleeding site was shown in 27 of 30 (90%) patients with glomerulopathy and in all 17 patients with bleeding from the lower urinary tract, indicating that this method of analysis has a sensitivity of 90% and specificity of 100% for detecting the glomerular source of bleeding. CONCLUSIONS: The examination of urine for dysmorphic and isomorphic red blood cells by phase contrast microscopy is strongly recommended in routine clinical practice for the detection of glomerular and non-glomerular lesions. This technique may avoid unnecessary investigations for the diagnosis of the site of bleeding in patients with haematuria.

Can renal blood flow, glomerular filtration rate or 99mTc-DMSA uptake predict outcome in experimental unilateral renal obstruction?

Single kidney glomerular filtration rate (SK GFR), single kidney blood flow (SK BF) and differential renal function (DRF), using both technetium labelled diethylene-pentaacetic acid (99mTc-DTPA) and dimercaptosuccinic acid (99mTc-DMSA), were examined as predictors of outcome in a pig model of complete unilateral ureteric obstruction. SK GFR and SK BF were unable to predict outcome following relief of obstruction but there was a high curvilinear correlation between DRF assessed at the end of defined periods of obstruction and after relief of obstruction using 99mTc-DMSA. Functional recovery was near complete using DMSA when the loss in DRF did not exceed 30%, after which there was an exponential decline in expected recovery. There was no difference between DRF using 99mTc-DTPA or 99mTc-DMSA in controls or before or after obstruction but significant differences between assessment by these radionuclides existed in the obstructed kidney at 24 h, 5 days, 10 days and 20 days. 99mTc-DMSA is a sensitive agent in the prediction of outcome following acute complete obstruction in the pig but its assessment of DRF in the obstructed kidney differs markedly from that of 99mTc-DTPA.

Transurethral microwave treatment for benign prostatic hypertrophy: a randomised controlled clinical trial.

OBJECTIVES: To determine whether transurethral microwave treatment for patients with benign prostatic hypertrophy provides significant symptomatic relief, a reduction in residual urine volumes, and improvements in flow rates compared with sham treatment. DESIGN: Prospective double blind randomised study with follow up at three months. SETTING: Department of Urology in a London teaching hospital. PATIENTS: 40 men completed the study: 22 received microwave treatment and 18 received sham treatment. Entry criteria were symptoms of prostatism of at least six months' duration, a total symptom score > 14, and a peak urine flow rate < 15 ml/s or a residual urine volume > 50 ml. Exclusion criteria were prostatic cancer, a residual urine volume > 200 ml, a very large prostate, an obstructing middle lobe, acute urinary retention, impaired renal function, coexisting urinary tract disease, and previous prostatic surgery. INTERVENTIONS: A single 90 minute transurethral microwave treatment or sham treatment. OUTCOME MEASURES: Patients' symptoms (including daytime frequency and nocturia) recorded in a self assessment symptom score questionnaire, peak urinary flow rates, and residual urine volumes. RESULTS: The mean total symptom scores of the patients who received microwave treatment fell from 30 to 11 compared with a fall from 31 to 26 for patients who received sham treatment (p < 0.001). Among patients who received microwave treatment daytime frequency fell from 9.4 to 5.5 voids a day and night time frequency from 3.5 to 1.6 voids a night; residual urine volumes fell from 104 ml to 52 ml; and peak urine flow rates increased by 2.3 ml/s. In the control group there was no improvement in any of these features. Treatment preserved sexual function and antegrade ejaculation. CONCLUSIONS: For selected patients with prostatism microwave treatment is effective and has few side effects.

Urinary tissue factor levels in prostatic carcinoma: a potential marker of metastatic spread?

Recent investigations have suggested that levels of urinary tissue factor (UTF) may be elevated in some forms of cancer. We have determined UTF levels in healthy controls, patients presenting for surgery with benign prostatic hypertrophy (BPH) and untreated prostate cancer. Patients undergoing check cystoscopy, who were free of recurrent bladder cancer, and a cohort of men with bone scan positive prostate cancer recently treated by androgen ablation were also studied. UTF levels were higher in patients with prostate cancer when compared with controls, those undergoing check cystoscopy and patients with BPH. In patients with prostate cancer, bone scan positive patients had higher levels than bone scan negative subjects. The androgen ablated group had UTF levels similar to those of the control groups and significantly lower than the bone scan positive group. A weak correlation was found between UTF and serum prostate specific antigen (PSA) levels when patients with BPH and untreated cancer were analysed, but no correlation was demonstrable between PSA and UTF when cancer patients alone were evaluated. It was concluded that UTF levels are elevated in untreated prostate cancer and reflect bone scan status. In patients with bone scan positive disease UTF also reflects disease activity and may therefore be a useful disease marker in prostate cancer.

Tethered cord syndrome: an unusual cause of adult bladder dysfunction.

Tethered cord syndrome is a complication of spinal dysraphism. The tethering of the cord does not permit the normal cranial migration of the conus within the vertebral canal and this results in neural dysfunction due to a traction neuropathy. Although this condition commonly presents in childhood, less severe degrees of tethering may remain asymptomatic until adult life. The clinical features, imaging and management of 5 adults with this condition are reviewed. Both urological and neurosurgical intervention are aimed at preservation of function as, unlike the sensorimotor deficit that commonly complicates this condition, improvement in bladder function is uncommon following cord release.

Coagulopathy in the prostate cancer patient: prevalence and clinical relevance.

Carcinoma of the prostate has historically been associated with the bleeding diathesis which accompanies disseminated intravascular coagulation. We have performed a prospective study into the prevalence of coagulopathy in patients with untreated prostate cancer using matched patients with benign prostatic hypertrophy (BPH) as controls. Haemostatic activation was assessed by measuring fibrinopeptide A (FpA) by an ELISA and D-dimer by a latex agglutination assay. FpA and D-dimer levels were correlated with serum prostate specific antigen (PSA) and bone scan status. Of the cancer patients, 40% had elevated FpA, levels being higher in those with bone scan positive disease (P < 0.05). D-dimer was detectable in 24% of those with prostate cancer but in none with BPH. Neither FpA nor D-dimer were related to serum PSA but D-dimer appeared to be a predictor of bone scan status with a positive predictive value of 91%. It is concluded that changes compatible with subclinical DIC are common in patients presenting with prostate cancer and that measurement of FpA and D-dimer may have roles as tumour markers in this disease.

Urinary tissue factor levels in transitional cell carcinoma of the bladder.

Production of procoagulant activity by host and tumour cells may be increased in patients with cancer. Using a simple chromogenic assay, we have determined urinary tissue factor (TF) levels in patients presenting with transitional cell carcinoma of the bladder (TCC, n = 63), normal controls (n = 20) and patients with benign prostatic hypertrophy (BPH, n = 35). In addition, a separate cohort of patients undergoing endoscopic surveillance for superficial bladder cancer were studied to determine whether there was any difference in levels in those with recurrent disease compared to those with normal cystoscopies. Urinary TF activity was higher in TCC compared to controls (p less than 0.001) and patients with BPH (p less than 0.05). In patients undergoing check cystoscopy, those with recurrent disease (n = 32) had higher levels (p less than 0.01) than those with normal examinations (n = 21). It is concluded that urinary TF levels are elevated in bladder cancer and that this reflects disease activity in those at risk of recurrent superficial disease.

Endoscopic placement of CAPD catheters: a review of one hundred procedures.

One hundred consecutive endoscopically placed peritoneal dialysis catheters inserted in 95 patients over an 18-month period have been reviewed. All catheters were placed for chronic dialysis (CAPD). Following insertion there were five early catheter failures (4 failed to drain, 1 perforated viscus) and 13 early complications (7 leaks, 3 tunnel bleeds, 2 scrotal oedema, 1 wound infection). In the long term six patients required transfer to haemodialysis (2 recurrent peritonitis, 2 pain on outflow, 1 unable to cope, 1 persistent vomiting). Overall probability of catheter survival as predicted by Kaplan-Meier analysis was 0.85 at 18 months. These results confirm that endoscopic placement of CAPD catheters is safe and reliable. In addition there is a low early failure rate and the long-term catheter survival figure is comparable with the best series reported. This procedure allows direct visualization of the peritoneal cavity, thus minimizing the risk of visceral damage. Furthermore, the procedure is well tolerated under local anaesthesia and allows early institution of dialysis because of the extremely low leakage rate (11%). Endoscopic placement of CAPD catheters is now the procedure of choice in our centre. General anaesthetic and mini-laparotomy are thus avoided in most of this high-risk group.

Urinary endothelin (ET1) in complete ureteric obstruction in the miniature pig.

Segmental renal scarring occurs in experimental obstructive uropathy in the multipapillary porcine kidney, and segmental abnormalities in renal perfusion are likely to be responsible. This preliminary study examines the urinary excretion of the potent locally active vasoconstrictor endothelin 1 (ET 1) in a pig model of renal obstruction and subsequent relief. Significant urinary excretion of ET 1 from the postobstructive kidney was found to occur after longstanding obstruction. Preglomerular arteriolar stenosis may be the cause of the renal ischaemia in obstruction that is at first reversible but later becomes irreversible if the stimulus persists. ET 1 may be implicated in the pathogenesis of this injury.