Multiple cholesterol emboli syndrome--six cases identified through the spontaneous reporting system

Six cases of suspected multiple cholesterol emboli syndrome were identified by a review of reports contained in the company's records of adverse event reports. Antecedent risk factors in these reports included cardiac catheterization, thrombolytic therapy, translumbar aortography, renal arteriography, subclavian arteriography, abdominal aortography, and heparinization. Unlike the commonly reported subacute presentation, onset occurred during or immediately after catheterization in 5 of the 6 patients reported. Acute renal failure; hypertension; back, leg, and/or abdominal pain; and livedo reticularis were the events most frequently reported. Angiographers should consider multiple cholesterol embolization when multiple organ system dysfunction occurs during or immediately after intraarterial catheterization.

An evaluation of type A and B alcoholics

Evaluations of 1539 alcohol-dependent subjects (including 512 women) were carried out in an attempt to replicate the Type A/B dichotomy suggested by Babor et al. (1992). The subjects are participants in the Collaborative Study on the Genetics of Alcoholism (COGA), and each was evaluated using a face-to-face structured interview. Following the procedure of Babor et al. (1992), data were used to create 17 domains, and a k-means clustering method was invoked to generate a two-cluster solution. Thirty-one per cent of the males and 25% of the females fell into the Type B group, with overall R2 of 0.22 and 0.24 for males and females, respectively. The scores in each of the 17 domains and the analyses of the clinical characteristics for Type A and B subjects were, in general, consistent with the earlier onset and more severe course for Type B men and women. The ability of the domains to identify subgroups of alcoholics remained robust even after the exclusion of alcohol dependent subjects with antisocial personality disorder (ASPD) and those with an onset of alcohol dependence before age 25 years. The present analyses suggest that five of the 17 domains might be especially useful in identifying Type A and B groups.

Stereochemistry of the Aplysia neuronal 12-lipoxygenase: specific potentiation of FMRFamide action by 12(S)-HPETE

Nervous tissue of the marine mollusc, Aplysia californica, generates arachidonic acid metabolites in response to neurotransmitters such as histamine or FMRFamide. In addition, identified neurons of Aplysia respond to the pharmacologic application of some of these products, particularly those of the 12-lipoxygenase pathway. We investigated the chirality of the initial Aplysia 12-lipoxygenase product, 12-HPETE, in preparation for more detailed metabolic studies and for the analysis of the physiological activity of the endogenous lipid. Neural homogenates and intact ganglia exclusively generate 12(S)-HPETE as do the better characterized mammalian lipoxygenases. The direct application of 12(S)-HPETE to cultured sensory neurons induced a hyperpolarization which averaged 2.6 mV. We did not find any difference between the response to the naturally-occurring 12(S)-HPETE and its diastereomer, 12(R)-HPETE which is not generated in Aplysia. Both isomers were significantly more effective than 15(S)-HPETE. In contrast, 12(S)-HPETE, but not 12(R)-HPETE, was a potent modulator of the action of the molluscan neuropeptide, FMRFamide. Prior application of 12(S)-HPETE to cultured sensory neurons increased the subsequent response to a submaximal dose of FMRFamide by 60%. On the other hand, 12(R)-HPETE reduced the subsequent response to the peptide by 30%. The lack of stereospecificity in the direct effect of the lipids differs markedly from their stereospecific effects as modulators of FMRFamide action. This suggests that there may be an important neurophysiologic role for these lipid modulators which is distinct from their direct effects, and also indicates that there are multiple sites and mechanisms by which lipid hydroperoxides act on neurons in Aplysia.

Pathophysiology of clinical benign prostatic hyperplasia

The pathophysiology of clinical BPH has been attributed to bladder outlet obstruction resulting from the enlarged prostate. A direct relationship does not exist between prostate size, symptom severity, or bladder outlet obstruction. The pathophysiology of prostatism is most likely multifactorial. Elucidating the factors contributing to symptoms will likely provide the foundation for the development of new pharmacological alternatives for the medical treatment of BPH.

Regional concentration of basic fibroblast growth factor in normal and benign hyperplastic human prostates

Basic fibroblast grown factor (bFGF) is a potent mitogen for mesenchymal cells, including fibroblasts cultured from prostate, and has been postulated to play a role in the development of benign prostatic hyperplasia (BPH). If this is the case, it might be expected that bFGF levels would be elevated in the adenomas of BPH and in the periurethral region of the prostate where BPH is believed to arise. This study was undertaken to test this hypothesis. The concentration of bFGF was evaluated in 31 prostates, 13 normal glands and 18 with BPH. A method for quantitating bFGF by radioimmunoassay was developed that enabled growth factor levels to be correlated to the geographic region of the prostate and the histopathology of the specimen. A 2- to 3-fold higher concentration of bFGF (ng./g. of tissue) was noted in the benign hyperplastic prostates when compared with the adult normal glands. Pubertal specimens demonstrated low growth factor levels comparable to those observed in the normal adult group. Two prepubertal prostates analyzed had high levels similar to those measured in the hyperplastic glands. While the levels of bFGF in the normal adult prostates were highest in the periurethral region, statistical analysis failed to demonstrate a significant difference. Similarly, quantitative morphometric evaluation failed to demonstrate any significant differences in bFGF concentration related to the proportion of stromal, epithelial, or lumenal elements in the tissue sections.

Effects of nitric oxide on human and canine prostates

OBJECTIVES

To determine whether nitric oxide (NO) is a mediator of prostatic smooth muscle activity.

METHODS

Pharmacologic experiments using electrical field stimulation (EFS) were performed on strips of human and canine prostate.

RESULTS

EFS alone elicited frequency-dependent contractions in preparations of human and canine prostates. The greatest contractile activity was achieved at 30 Hz. In the presence of 10(-5) M guanethidine (GUA) and 2 x 10(-6) M atropine (ATR), EFS elicited relaxation of canine prostate strips relative to baseline tension. A weak biphasic response consisting of initial relaxation and subsequent contraction relative to baseline tension was observed in the human prostate strips exposed to similar conditions. The smooth muscle activity observed in the presence of GUA plus ATR was attributed to nonadrenergic, noncholinergic (NANC) nerve transmission. 10(-4) M L-NG-nitroarginine methylester (NAME) significantly increased EFS-elicited NANC smooth muscle activity both in human and canine prostates. L-arginine, 10(-2) M, reversed the effect of L-NAME in human and canine prostates. Sodium nitroprusside, 10(-4) M, a donor of NO, caused relaxation of both human and canine prostates. The mean magnitude of the relaxant response/cross-sectional area in human prostate (2.64 +/- 0.4 g/cm2) was significantly greater than in the canine prostate (1.09 +/- 0.17 g/cm2) (P < 0.005).

CONCLUSIONS

These results provide compelling evidence that NO plays a role in mediating contractile function of human and canine prostates.

Serial MR after bone marrow transplantation in two patients with metachromatic leukodystrophy

Two children with metachromatic leukodystrophy underwent bone marrow transplantation. In both patients MR subsequently showed, first, white matter changes, then later, lack of change as the patients stabilized clinically.

Drug use among primary alcoholic veterans

Many people with alcohol dependence use other drugs. However, not much is known about the relationship between their past drug use (not necessarily dependence) and their prognosis following treatment. The goal of this study is first to determine the drug use rates among primary alcoholic men and then to evaluate the possible relationship between past drug use and future alcohol or drug use relapse. As a result, 630 primary alcoholic veterans were recruited from a 28-day inpatient Alcohol and Drug Treatment Program at the San Diego VA Medical Center. Among them, almost two-thirds also had a history of drug use. Subjects were divided into the following four groups which were determined by their lifetime drug use histories: Group I (N = 226) consisted of drug abstainers, Group 2 (N = 142) was made up of alcoholics who had used only marijuana, Group 3 (N = 210) contained stimulant users who had never used opiates, and Group 4 (N = 52) included all opiate users. Comparisons of the four groups at a 3-month follow-up revealed that alcoholic men who had a history of stimulant or opiate use (Groups 3 and 4) were more likely to have had a drug use relapse. However, the four groups had similar alcohol relapse rates.

Adrenoleukodystrophy: a scoring method for brain MR observations

PURPOSE

To develop a scoring method for brain observations in patients with X-linked adrenoleukodystrophy.

METHODS

One hundred seventy-five brain MR scans in 83 male subjects less than 20 years of age with proved biochemical defects were reviewed. A severity score (0 to 34), based on a point system derived from location and extent of disease and the presence of focal and/or global atrophy, was calculated for each exam.

RESULTS

Fifty-five of the 83 patients showed MR findings consistent with adrenoleukodystrophy. Two major patterns were observed. A posterior pattern (mean score, 9; range, 0.5 to 25) was present in 80% of patients, and an anterior pattern (mean score, 10; range, 2 to 18) was present in 15% of patients. Serial MR imaging, positive for adrenoleukodystrophy in 34 patients (mean follow-up, 23 months; range, 2 months to 6 years 11 months), showed progressive disease in 52%, progressive disease with subsequent stabilization in 18%, stable disease in 24%, and minimal improvement in 6%.

CONCLUSION

The adrenoleukodystrophy MR severity scoring method is a measure that can be used with standard MR images. When used in conjunction with clinical parameters, this scoring method may help define better the natural history of adrenoleukodystrophy and monitor response to developing therapies.

Childhood cerebral form of adrenoleukodystrophy: short-term effect of bone marrow transplantation on brain MR observations

PURPOSE

To report the serial brain MR observations in patients with childhood-onset cerebral adrenoleukodystrophy 1 to 2 years after bone marrow transplantation.

METHODS

Eight boys with childhood-onset cerebral adrenoleukodystrophy have undergone successful transplantation at our institution. Seven patients (mean age, 8 years 10 months; range, 5 years 3 months to 11 years 9 months) had serial MR studies before and after transplantation. An MR severity score (0 to 34) based on disease location and the presence or absence of focal atrophy was calculated for each patient scan.

RESULTS

Posttransplantation serial MR showed improvement in two patients, stabilization in three patients, and worsening of MR signal changes in two patients. The patient with the most striking progression had systemic graft-versus-host disease. Although the adrenoleukodystrophy MR severity score did not change in three patients after transplantation, two of these patients did show improved margination of disease.

CONCLUSION

Bone marrow transplantation can affect brain MR observations in childhood-onset cerebral adrenoleukodystrophy. Although brain MR findings do not typically resolve, they do seem to stabilize, which is an improvement over the natural MR history of the disease.

A comparison of the binding and functional properties of alpha-1 adrenoceptors and area density of smooth muscle in the human, canine and rat prostates

The present study was designed to compare the binding and functional properties of alpha-1 adrenoceptors and the area density of smooth muscle in the human, canine and rat prostates. Chloroethylclonidine (CEC)-sensitive and -insensitive alpha-1 adrenoceptors were characterized on slide-mounted prostatic tissue sections using the ligand [3H]prazosin. The mean equilibrium dissociation constants (Kd) for [3H]prazosin binding sites were not significantly different among the three different species. The densities (Bmax) of CEC insensitive [3H]prazosin binding sites in the human, canine and rat prostates were 1.71 +/- 0.32, 0.35 +/- 0.04 and 0.84 +/- 0.11 fmol/mg of wet weight, respectively. The Bmax of CEC-sensitive [3H]prazosin binding sites in the human, canine and rat prostates were 1.32 +/- 0.83, 0.44 +/- 0.11 and 0.25 +/- 0.10 fmol/mg of wet weight, respectively. The contractile response elicited by the rat prostate in the presence of phenylephrine was consistently negligible. The mean maximal force after phenylephrine challenge (phenylephrine Emax) in the human and canine prostates were 0.125 +/- 0.025 g of force/mm2 cross-sectional area and 0.096 +/- 0.014 g of force/mm2 cross-sectional area, respectively. CEC inactivated 80 and 53% of the phenylephrine contractile response in man and dog, respectively. The mean percentage of area densities of smooth muscle in the human, canine and rat prostates were 38.8, 12.9 and < 1%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between prostatic epithelial volume and serum prostate-specific antigen levels

OBJECTIVES

The present study was designed to determine the relationship between serum prostate-specific antigen (PSA) levels and prostatic epithelial volumes.

METHODS

Forty-two men between the ages of 50 and 79 years of age with either an abnormal digital rectal examination (DRE) or a serum PSA level > 4 ng/dL underwent transrectal ultrasonography (TRUS) and ultrasound-guided random systematic biopsy of the prostate. The volumes of the peripheral zone (PZ) and transition zone (TZ) were calculated, assuming that the total prostate and TZ are ellipsoidal structures. Six random systematic biopsies were directed into the PZ and four random systematic biopsies were directed into the TZ under ultrasound guidance. Among the 42 patients undergoing prostatic biopsy, adenocarcinoma of the prostate was identified in 21 (50%). Tissue sections obtained from the biopsy specimens of the subjects without histologic evidence of prostate cancer were stained with Mallory trichrome stain, and the percentage area density of epithelium in the biopsy cores was determined using computer-assisted color image analysis. The relationships between serum PSA and total, PZ, and TZ epithelial volumes, and serum PSA and total, PZ, and TZ prostatic volumes were determined using regression analysis.

RESULTS

The difference between the mean percentage epithelial density of the PZ (17.79 +/- 1.40%) and TZ (10.32 +/- 0.82%) was statistically significant (p < 0.0001). The mean volumes of epithelium in the PZ and TZ were 4.25 +/- 0.47 cc and 3.39 +/- 0.45 cc, respectively. The p and r2 values for the relationship between serum PSA and total prostatic volume were 0.016 and 0.260, respectively. Statistically significant correlations were also observed between serum PSA levels and TZ epithelial volumes (p = 0.0009; r2 = 0.449) and serum PSA levels and TZ volumes (p = 0.007; r2 = 0.329). Statistically significant correlations were not observed between serum PSA levels and the following parameters: PZ volume, PZ epithelial volume, and total prostatic epithelial volume.

CONCLUSIONS

Although the PZ contains a significantly greater area density and absolute volume of epithelium than the TZ, the serum PSA level is most strongly correlated only with the volume of epithelium in the TZ.

Loss of elasticity in dysfunctional bladders: urodynamic and histochemical correlation

To store adequate volumes of urine at low safe pressures an elastic bladder wall is required. We developed 2 new techniques to measure this ability in our urodynamic laboratory: pressure specific bladder volume, which measures the bladder capacity at a given pressure, and dynamic analysis of bladder compliance. Recently, morphometric and histochemical techniques have been used to determine the relative volume of connective tissue in the bladder wall and to measure the 2 major types (I and III) of collagen within the bladder wall. These methods quantitate 3 parameters of bladder ultrastructure: 1) relative volume of per cent connective tissue, 2) ratio of connective tissue to smooth muscle and 3) ratio of type III to type I collagen. These parameters have been shown to be abnormally elevated in patients with dysfunctional bladders compared to normals. The purpose of the study was to describe the ultrastructural changes that occur in the wall of dysfunctional bladders and to determine the ability of these new urodynamic techniques to detect reliably the clinical effect of these histological changes. The study included 29 consecutive patients with dysfunctional bladders necessitating bladder augmentation. All patients had upper tract changes and/or were incontinent despite treatment with clean intermittent catheterization and pharmacotherapy. Preoperative urodynamic evaluation included measurement of the total bladder capacity, pressure specific bladder volume and dynamic analysis of bladder compliance. Full thickness bladder biopsies were obtained from the dome of the bladders during augmentation. The per cent connective tissue and the ratio of connective tissue to smooth muscle were determined for all patients, and 4 unselected patients from this group had the ratio of type III to type I collagen determined. These histological results were compared to previously established normal values. All 29 patients had a decreased pressure specific bladder volume and dynamic analysis of bladder compliance, whereas 9 had a normal total bladder capacity. The per cent connective tissue was 35.19 +/- 2.84 and ratio of connective tissue to smooth muscle was 0.60 +/- 0.08 compared to normal values of 10.6 +/- 0.020 and 0.131 +/- 0.021, respectively (p < 0.05). Ratio of type III to type I collagen was also significantly elevated in the 4 samples analyzed (30.53 +/- 1.37 versus 24.00 +/- 2.50, p < 0.05). We conclude that poor storage function of poorly compliant bladders is secondary to an alteration in the connective tissue content of the bladder wall. Furthermore, these pathological ultrastructural changes are universally reflected by an abnormally low pressure specific bladder volume and dynamic analysis of bladder compliance. This strong association validates the use of these parameters and suggests that they are urodynamic indicators of a loss of elasticity in bladder wall.

Invasive bacterial infections in children born to women infected with human immunodeficiency virus type 1

To determine the rates and characteristics of invasive bacterial infections in children infected with the human immunodeficiency virus type 1 (HIV-1), we conducted a prospective, longitudinal, observational cohort study of infants born to HIV-1-infected mothers between Dec. 1, 1985, and Sept. 30, 1989. Of 104 subjects whose HIV-1 infection status could be definitively determined, 21 were infected with HIV-1 and 83 were not. In all, 11 (48%) of 23 invasive infections occurred among 10 HIV-1-infected patients and 12 (52%) of 23 occurred among 11 uninfected subjects. Infections with Streptococcus pneumoniae (n = 8), all of which were community acquired, accounted for the greatest proportion (35%) of the organisms isolated from either the blood or the cerebrospinal fluid. Five episodes of pneumococcal bacteremia occurred in the HIV-infected patients; all resolved promptly after treatment was begun, and no serious focal infections developed. Of 13 instances of bacteremia with an organism other than S. pneumoniae, seven were nosocomial. The rate of community-acquired invasive bacterial infections among the HIV-infected children was nearly three times higher than the rate in the non-HIV-infected children (overall, 1.02 infections per 100 person-months vs 0.37 infection per 100 person-months; rate ratio, 2.8; p = 0.05). Most of the increased risk occurred in children > 1 year of age. In contrast, the difference in the rates of infection between those patients in the two groups who were less than 12 months of age was not significant (1.3 infections per 100 person-months vs 0.81 infection per 100 person-months; rate ratio, 1.6; p = 0.47). We conclude that the rate of invasive bacterial infection is higher in HIV-infected children than in their peers, especially after 1 year of age.

The alpha 1-adrenergic receptor that mediates smooth muscle contraction in human prostate has the pharmacological properties of the cloned human alpha 1c subtype

Molecular cloning studies have revealed the existence of three subtypes of alpha 1-adrenergic receptors. However, the link between any individual subtype and its functional role in the body has remained elusive. In an effort to bridge the gap between molecular biology and pathophysiology, we have chosen a model smooth muscle system, the human prostate, and investigated the role of alpha 1 subtypes in this tissue. To determine which alpha 1-adrenergic receptor subtype mediates the contractile response of the human prostate, we first studied the pharmacological properties of three cloned human alpha 1 subtypes (alpha 1a/d, alpha 1b, and alpha 1c). Prazosin, terazosin, doxazosin, alfuzosin, and abanoquil showed no selectivity for the human alpha 1 subtypes. WB-4101 and 5-methylurapidil showed a rank order of potency of alpha 1c > alpha 1a/d >> alpha 1b. Indoramin and (+)-niguldipine were selective for the alpha 1c-adrenergic receptor, with at least 10-fold lower affinity at either alpha 1a/d or alpha 1b subtypes. SK&F104856 was found to be 6-fold more potent at the alpha 1a/d receptor subtype than at alpha 1b- or alpha 1c-adrenergic receptors. We next determined the potency of these antagonists to inhibit the phenylephrine-induced contraction of human prostatic tissue in vitro. The potencies of indoramin, 5-methylurapidil, and SK&F104856 to inhibit the contractile response and to displace [3H]prazosin from the cloned human alpha 1c subtype were similar. Our data suggest that the alpha 1 receptor that mediates the contraction of human prostate smooth muscle has the pharmacological properties of the cloned human alpha 1c-adrenergic receptor. The findings of the present study suggest that selective alpha 1c-adrenergic receptor antagonists may be clinically more efficacious and better tolerated agents for the treatment of symptomatic benign prostatic hyperplasia.

Localization of endothelin receptors in the human prostate

The objective of the present study was to localize endothelin receptors in the human prostate using quantitative autoradiography. Slide-mounted tissue sections 20 microns. in thickness were obtained from the transition zones of seven patients undergoing radical prostatectomies for low volume prostate cancer. Sarafotoxin (S6C) and BQ123 have been used to distinguish endothelin receptor subtypes (ETA and ETB). The prostatic tissue sections were incubated in four different stock solutions containing the following: 0.1 nM. 125I-endothelin-1 (125I-ET-1) (total ET-1 binding); 0.1 nM. 125I-ET-1 and 100 nM. S6C (total ETA binding); 0.1 nM. 125I-ET-1 and 1 microM. BQ123 (total ETB binding); and 0.1 nM. 125I-ET-1 and 1 microM. ET-1 (nonspecific ET-1 binding). Nonspecific binding accounted for only 12 and 15% of total 125I-ET-1 binding in the stroma and glandular epithelium. Autoradiograms were quantitatively analyzed using a computerized image analysis system. Specific radioactive densities (nCi/mg.) were determined for the stromal and glandular epithelial elements of the prostate. The specific radioactive densities of ETA and ETB binding sites in the stroma were 7.57 +/- 0.65 and 2.98 +/- 0.81. The specific radioactive densities of ETA and ETB binding sites in the glandular epithelium were 1.59 +/- 0.15 and 7.87 +/- 1.35. The present study demonstrates that the predominant endothelin receptors in the stroma and glandular epithelium are the ETA and ETB subtypes, respectively.

Making managed care work for you. Tips on setting up a cost-effective practice

Making a practice cost-effective and profitable does not have to come at the expense of quality care. By incorporating managed care into their practices, the authors were able to find a successful balance. In this article, they lay out tips that would benefit physicians thinking of setting up their own managed-care centers as well as those looking to fine-tune or expand their current practices.

Fungal sepsis: multisite colonization versus fungemia

The indications for therapy and the best treatment regimens for systemic fungal infections are not well defined. The purpose of this study was to evaluate retrospectively patient management and outcome in critically ill patients with multiple sites of fungal colonization and/or fungemia. Medical records of 36 fungemic patients and 76 patients without fungemia who had two or more anatomic sites colonized with fungal organisms were reviewed. There were 53 males and 59 females, with a mean age of 58 years (range 15-86). Eighty-four patients (74%) underwent 238 operations (41% elective, 59% emergent). Gastrointestinal (37%), thoracic (15%), and orthopedic (13%) procedures were most common. Concomitant, nonfungal bacteremia was present in 56 patients (50%). Seventy-one patients (63%) received systemic antifungal therapy. Mortality differences between patients with fungemia (17/36; 47%) and fungus-colonized patients (31/76; 41%) were not statistically significant. Amphotericin B treatment of fungemia reduced mortality overall (26% vs 71%, P < 0.05) and compared with fungemic patients receiving other antifungals (26% vs 50%, P < 0.05). Among fungus-colonized patients, mortality was higher with amphotericin B than without (70% vs 36%, P < 0.05) and was not changed by treatment with other antifungals (37% vs 34%). Increased gastrointestinal operations, wound infections, and intraperitoneal fungi and bacteria in fungus-colonized patients receiving amphotericin B suggest that these patients were the most critically ill. The mortality of multisite fungal colonization is as high as that of fungemia. Only amphotericin B improves survival in fungemia. The best treatment for multisite colonization is not clear from the data.

Binding and functional properties of endothelin receptor subtypes in the human prostate

The objective of the present study was to characterize the binding and functional properties of endothelin (ET) receptor subtypes in the human prostate. Human prostatic tissue was obtained from male subjects undergoing radical prostatectomy for low-volume prostate cancer. The optimal assay conditions for characterizing human prostatic ET-1 binding sites on slide-mounted tissue sections were defined. Maximal specific 125I-ET-1 binding was achieved after a 10-min preincubation, a 120-min incubation, and a washing procedure that consisted of a brief rinse and a 1-min wash. The mean equilibrium dissociation constant (Kd) and density (Bmax) of ET-1 binding sites determined from six saturation studies were 0.72 +/- 0.13 nM and 40.4 +/- 6.9 fmol/mg of wet weight, respectively. The mean Hill coefficient was 0.99 +/- 0.01, indicating that 125I-ET-1 identifies a single population of binding sites. The pharmacology of 125I-ET-1 binding sites was characterized using competitive binding experiments. The competition plots for ET-1 were best fit by a one-binding site model, whereas the plots for sarafotoxin 6C (S6C) and BQ123 were consistently best fit by a two-site model. The mean Ki value of ET-1 was 0.34 +/- 0.12 nM. The mean Ki values for the high and low affinity S6C binding sites were 0.50 +/- 0.09 nM and 0.84 +/- 0.28 microM, respectively. The mean Ki values for the high and low affinity BQ123 binding sites were 5.51 +/- 1.05 nM and 24.9 +/- 6.5 microM, respectively. The ratio of ETA to ETB binding sites was approximately 2:1. The ET receptor subtype mediating prostatic smooth muscle tension was investigated using agonist-antagonist competition studies. ET-1, a nonselective ET agonist, elicited a potent contraction of prostate smooth muscle. The pA2 of BQ123 for inhibiting ET-1-mediated contraction was 6.84. S6C, a selective ETB agonist, also elicited a potent contraction of prostate smooth muscle. BQ123 at concentractions between 0.1 and 10 microM did not shift the S6C dose-response curve. These functional studies suggest that both ETA and ETB receptors mediate the tension of prostate smooth muscle. Endogenous ETS may be involved in the pathophysiology of bladder outlet obstruction in men with benign prostatic hyperplasia. If this is the case, then ET antagonists may represent effective treatment for benign prostatic hyperplasia.

Characterization and localization of prostatic alpha 1 adrenoceptors using radioligand receptor binding on slide-mounted tissue section

Alpha 1 adrenoceptor binding sites have been characterized in prostatic tissue homogenates using radioligand receptor binding studies. The objective of the present study was to characterize and localize prostatic alpha 1 adrenoceptor binding sites using slide-mounted tissue sections and the ligand 3H-prazosin. The present study demonstrated that preincubation is not required; the optimal incubation interval is 40 minutes; and a 1-minute wash (once or twice) maximizes the proportion of specific 3H-prazosin binding. Saturation studies were performed at 8 different concentrations of 3H-prazosin ranging between 0.0625 nM. to 8.0 nM. The binding of 3H-prazosin was consistently saturable and of high affinity. The mean Kd and Bmax determined from 6 saturation studies was 4.16 x 10(-10) M. and 1.30 fmol./mg. wet weight, respectively. The pharmacology of these 3H-prazosin binding sites was characterized using competitive displacement experiments. The mean IC50 corrected for prazosin, phentolamine and yohimbine was 7.8 x 10(-10) M., 6.0 x 10(-9) M. and 2.1 x 10(-6) M. The rank order of the IC50 corrected values indicates that alpha 1 binding sites were measured under the assay conditions. In the present study, the mean values for Kd, Bmax and IC50 corrected are similar to values previously reported using prostatic tissue homogenates. Prostatic tissue sections were apposed to x-ray film after being incubated with 3 nM. 3H-prazosin (total prazosin binding) and 3 nM. 3H-prazosin + 8 microM. prazosin (nonspecific prazosin binding). The autoradiograms were analyzed using a computerized analyzing system. The specific radioactive densities of 3H-prazosin in the stroma and glandular epithelium were 1099 +/- 48 pCi/mg. and 163 +/- 42 pCi/mg. The present study validates the technique of assaying alpha 1 adrenoceptor binding sites on slide-mounted prostatic tissue sections and provides further evidence that alpha 1 adrenoceptor binding sites are localized primarily to the stromal elements of the prostate.

Heating patterns of the Helios ultrasound hyperthermia system

Thermal dosimetry studies of the Helios ultrasound system were performed in a tissue-equivalent phantom and in porcine tissues in vivo. SAR distributions in the phantom demonstrate the adjustability of the power deposition pattern from the 50 cm diameter annular array of 30 transducers. Examples are given of well-localized SAR patterns (< 3 cm diameter) in the phantom, and of peripherally enhanced (doughnut-shaped) SAR patterns up to 10 cm in diameter at the focal plane. In vivo trials in porcine thigh muscle demonstrate the ability of the Helios system to produce regions of therapeutic heating (42-45 degrees C) as small as 20 cm3 and as large as 200 cm3 at depths of greater than 10 cm at a frequency of 0.5 MHz.

Endothelin-1 in the human prostate: tissue levels, source of production and isometric tension studies

Endothelins mediate contractile responses in many types of vascular and nonvascular smooth muscle. The present study represents the first detailed characterization of endothelins in the human prostate. The objectives of this study were to determine the tissue levels and source of endogenous endothelin-1 (ET1) in the human prostate. The contractile effects of ET1 were also investigated using in vitro isometric tension studies. The mean tissue level of ET1 was 0.58 +/- 0.08 pg./mg. tissue wet weight. Endothelin-like activity was markedly prominent in the glandular epithelium of the human prostate, whereas minimal endothelin-like activity was observed in the prostatic stroma. Strips of human prostatic tissue were suspended in isolated tissue chambers and challenged to a concentration response of ET1. The mean EC50 and Emax for ET1 was 3.2 x 10(-8) M. and 0.12 +/- 0.02 gm. force per mm.2 cross-sectional area (CSA), respectively. Preincubation with indomethacin, terazosin, or nifedipine did not alter the concentration-dependent response to ET1. A calcium-free buffer abolished the contractile response to ET1. Thus, ET1 mediates a potent contraction of human prostatic smooth muscle that is not mediated via alpha 1 adrenergic or dihydropyridine sensitive calcium channels or prostaglandin synthesis. The presence of marked endothelin-like immunoreactivity strongly suggests a biological significance for endogenous endothelins in the human prostate.

Pediatric urological manpower report. Pediatric Urological Manpower Committee of the American Association of Pediatric Urology

The American Association of Pediatric Urology initiated a Pediatric Urological Manpower Study in 1991. A 24-question survey was distributed to the members of the Society of Pediatric Urology and the American Academy of Pediatrics Section on Urology. The objective of the questionnaire was to obtain information related to fellowship training, regional distribution of pediatric urologists, and practice patterns and attitudes. As of December 31, 1991, 345 questionnaires were distributed, and 244 (71%) were completed and entered into a computer program. The number of pediatric urologists was evenly distributed among 3 consecutive 10-year age groups ranging between age 31 and 60 years. The majority (78%) of urologists practicing 100% pediatric urology were between 31 and 50 years old. Approximately 60% of the responders practiced full-time (100%) pediatric urology and 59% of this group were university based. Pediatric urologists were practicing in 42 states and the District of Columbia. Based upon the United States Department of Commerce 1990 census, the number of pediatric urologists practicing in each state in relation to the total pediatric (less than 18 years old) populations was determined. The number of pediatric urology fellowships has steadily increased since the mid 1950s. Currently, more than 10 fellows are trained annually. Of the 172 responders practicing at least 75% pediatric urology 24% indicated that practice was "too busy" and 53% indicated that practice was "just right." Approximately 44% of the responders were considering adding a partner: 21 indicated that they planned to add a partner in 1 year, 65 in 5 years and 10 in 10 years. Hopefully, the Pediatric Urological Manpower Study will serve as a useful instrument for assessing the pediatric practice patterns and training needs in the United States, thereby enhancing the quality of urological care for children.