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Biomedical subjects

I Goldstein

Publications and source records attributed to I Goldstein.

At least 19 recordsLinked to original sources
PubMed1992

Cardiotocographic and sonographic findings in two cases of antenatally diagnosed intrauterine fetal brain death.

Intrauterine fetal brain death is a rare cause of a fixed fetal heart rate pattern. Seven cases have been previously reported in the literature, but only two of them were diagnosed prenatally and all the newborns died soon after delivery. Two additional cases of antepartum diagnosis of intrauterine fetal brain death, managed expectantly, are reported. We had the unique opportunity to document progressive sonographic cerebral changes during the follow-up period, following the neurological event, while the fetus continued life and growth in utero. The cardiographic and sonographic findings suggesting intrauterine fetal brain death were a prolonged fixed fetal heart rate, even following a vibroacoustic and contraction stress test; an atonic fetus without breathing and body movement; and the appearance of hydramnios and the development of ventriculomegaly.

Adult↗
PubMed1992

The hemodynamic pathophysiology of impotence following blunt trauma to the erect penis.

A total of 19 patients provided a history of impotence following blunt trauma to the erect penis during intercourse or masturbation, or after accidents. Corporeal veno-occlusive dysfunction was the most common hemodynamic abnormality (16 of 19 patients, or 84%). A site-specific leak, which consisted of abrupt filling of the dorsal vein and/or corpus spongiosum from a focal site on the penile shaft, was demonstrated in 15 patients (79%). Cavernous artery insufficiency was found less often (7 of 19 patients, or 37%). A focal mid shaft cavernous artery occlusion was demonstrated in 5 patients (28%). It is hypothesized that the aforementioned hemodynamic abnormalities are caused by tunica and intracavernous vasculature injuries induced by the marked short-term pressure increases, which approach or exceed the tunica tensile strength during acute abrupt loading of the erect penis. This hypothesis is supported by direct recording of intracavernous pressures that exceeded 450 mm. Hg in response to angulation and manual compression of the penile shaft. Further evidence was created by a biomechanical model that was based on previously published intracavernous pressure--circumference patient data during dynamic infusion pharmacocavernosometry. Using a typical patient data set a 60% diminution of circumference at the site of abrupt loading was calculated to induce a 15% increase in circumference in the nonloaded portion of the penile shaft and an elevated intracavernous pressure exceeding 900 mm. Hg. The site-specific hemodynamic abnormalities were found to occur not only in patients with a classical penile fracture history but also in patients with injuries during masturbation or following accidents who had no acute penile swelling or ecchymosis. Thus, the erect penis is at risk for injury during any acute loading situation. It is likely that this erect trauma-induced hemodynamic pathology occurs more frequently than previously appreciated and that this type of impotence may be the underlying basis for many cases of idiopathic Peyronie's disease.

Adolescent↗
PubMed1992

Use of a polytetrafluoroethylene tube graft as a circumferential neotunica during placement of a penile prosthesis.

Various techniques have evolved for augmentation of the tunica albuginea in cases when tunical tissue has been found deficient during penile prosthesis implantation. An intraoperative situation occurred in which the size of the tunical defect did not permit primary tunical closure or allow for approximation by placement of a tunical patch graft. In this case, to ensure satisfactory insertion of a penile prosthesis a polytetrafluoroethylene (Gore-Tex) tube graft was used as a circumferential neotunica.

Adult↗
PubMed1992

Clozapine-associated priapism: a case report.

Priapism is a recognized side effect of antipsychotic therapy. Recently, new agents known as atypical antipsychotics, such as clozapine, have been introduced with the intent of ameliorating psychosis without the extrapyramidal side effects associated with standard antipsychotic therapy. Priapism has not been observed previously with atypical antipsychotic therapy. We report a case of veno-occlusive priapism associated with the use of clozapine. This priapistic episode was complicated by the development of recurrent post-ischemic priapism.

Adult↗
PubMed1992

Endothelium-derived nitric oxide and cyclooxygenase products modulate corpus cavernosum smooth muscle tone.

Relaxation of penile corpus cavernosum smooth muscle is controlled by nerve and endothelium derived substances. In this study, endothelium-dependent relaxation of corporal smooth muscle was characterized and the role of arachidonic acid products of cyclooxygenase in endothelium-dependent relaxation was examined. Endothelium removal from rabbit corpora was performed by infusion with 3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate and was confirmed by transmission electron microscopy. Strips of human and rabbit corporal tissues were studied in the organ chambers for isometric tension measurement. The accumulation of cyclic guanosine monophosphate (cGMP) and the release of eicosanoids from corporal tissue was measured by radioimmunoassay and correlated to smooth muscle relaxation. Our study showed that relaxation of corpus cavernosum tissue to acetylcholine, bradykinin and substance P was endothelium-dependent; potentiated by indomethacin; and inhibited by NG-monomethyl-L-arginine, methylene blue or LY83583. Relaxation to papaverine and sodium nitroprusside was endothelium-independent, and unaffected by NG-monomethyl-L-arginine. Relaxation to vasoactive intestinal polypeptide was partially endothelium-dependent; potentiated by indomethacin; attenuated by NG-monomethyl-L-arginine or methylene blue. The tissue level of cGMP was enhanced by acetylcholine and nitric oxide. Methylene blue inhibited both basal and drug-stimulated levels of cGMP. The release of eicosanoids was enhanced by acetylcholine and blocked by indomethacin. In conclusion, nitric oxide or a closely related substance accounts for the activity of endothelium-derived relaxing factor in the corporal tissue. Inhibition of the release of eicosanoids potentiates the relaxing effect of nitric oxide. Nitric oxide increases tissue cGMP which appears to modulate corporal smooth muscle relaxation.

Acetylcholine↗
PubMed1992

Erectile dysfunction due to atherosclerotic vascular disease: the development of an animal model.

An animal model was developed to study the pathophysiology of erectile dysfunction due to atherosclerotic vascular disease. Thirty one New Zealand white male rabbits were divided into control (n = 5) and treatment groups (n = 26). The control group was placed on a regular diet while the treatment group underwent balloon de-endothelialization of the aorto-iliac arteries and received 1.6% cholesterol and 4% triglyceride diet for eight weeks. After eight weeks in the control animals (n = 5), blood levels of cholesterol, triglycerides and low density lipoproteins, radiologic studies as well as hemodynamic parameters of erectile function were all normal. In the surviving treatment animals (n = 21) after the same time period, a significant increase in blood levels of cholesterol, triglyceride and low density lipoprotein were observed. In addition, 62% of these animals developed hypertension which was not observed in the control group. Angiographically, 10 animals (48%) demonstrated severe atherosclerotic lesions (75% to 100% occlusion of common or internal iliac arteries on one side and over 50% occlusion of the opposite side), five (24%) had moderate lesions (50 to 75% luminal occlusion of right and left common iliac or internal iliac arteries) and 6 revealed minimal lesions (less than 50% occlusion of the right and left common iliac or internal iliac arteries). Of the 15 animals with 50% or greater luminal occlusion of the iliohypogastric arteries, erectile dysfunction was found in 93% of cases. Due to the development of erectile dysfunction in 33% of animals with minimal occlusive lesions, it appears that factors, other than large vessel luminal occlusion, may exist in this animal model which adversely influence erectile function. This model may therefore be of further benefit in the study of other factors associated with atherosclerosis and impotence, such as the possible concomitant hypercholesterolemic and atherosclerotic-induced alterations in the local reactivity of corpus cavernosum smooth muscle and lacunar space endothelial cells.

Animals↗
PubMed1991

Fetal breathing movements after preterm premature rupture of membranes.

Forty-three patients with preterm premature rupture of membranes were studied between 24 and 34 weeks' gestation. Intraamniotic infection was excluded by amniocentesis. There were significantly fewer fetal breathing movements for the first 2 weeks of membrane rupture, compared with controls, with a return to near normal by the third week. This reduction in fetal breathing may play a role in the production of pulmonary hypoplasia in some of these patients. Further studies are needed to investigate whether ruptured membranes are associated with a reduction in fetal breathing at earlier gestational ages.

Female↗
PubMed1991

Pathophysiology of prolonged penile erection associated with trazodone use.

Treatment with the antidepressant trazodone has been associated with the occurrence of prolonged penile erection and priapism. To evaluate the effect of trazodone on erection we monitored the periodic physiological sleep-related erections in 6 healthy volunteers in a double-blind crossover study comparing the effect of trazodone, trimipramine (a tricyclic antidepressant) and placebo. In addition, to determine the effects of trazodone on the neurovascular control of penile smooth muscle we performed in vitro studies on corpus cavernosum tissue obtained from patients undergoing penile prosthesis implantation. Trazodone significantly increased the total interval of nocturnal erectile activity, while trimipramine had no effect. During the high dose treatment (nights 4 and 5) the average duration of erectile activity per night with placebo was 158 +/- 41 minutes (mean +/- standard deviation) for night 4 and 177 +/- 21 minutes for night 5. During trazodone treatment the erectile activity per night was significantly prolonged to 285 +/- 115 minutes during night 4 and 232 +/- 86 during night 5 (p less than 0.01). Analysis of the erectile activity in relation to the rapid eye movement sleep period during which erectile activity usually occurs revealed that the detumescence phase of erection, under sympathetic control, was significantly prolonged an average of 2.4 times by trazodone compared to placebo (p less than 0.05). In vitro, trazodone at concentrations comparable to those reached in plasma significantly impaired corporeal smooth muscle contractions elicited by electrical stimulation of adrenergic nerves and antagonized contractions induced by exogenous norepinephrine. We conclude that trazodone can enhance penile erection in man and propose a mechanism related to the alpha-adrenoceptor blocking properties of trazodone by interference with the sympathetic control of penile detumescence.

Adolescent↗
PubMed1991

Cigarette smoking: an independent risk factor for atherosclerosis in the hypogastric-cavernous arterial bed of men with arteriogenic impotence.

We investigated the relationship between cigarette smoking and atherosclerosis of the hypogastric-cavernous arterial bed by evaluating arteriograms of young impotent men referred for selective pudendal angiography. Those patients with hemodynamically significant atherosclerosis had smoked more pack-years than had patients without arterial disease. These differences were statistically significant (p less than 0.05) for the common penile artery (32.8 pack-years, 40 patients versus 22.3 pack-years 57 patients) and the dorsal artery (31.3 pack-years, 48 patients versus 22.0 pack-years, 49 patients). The effect of cigarette smoking as an independent risk factor for atherosclerotic disease in the hypogastric-cavernous arterial bed was evaluated as well. When controlled for age, trauma history, hypertension and diabetes, cigarette smoking was independently associated with atherosclerosis in the internal pudendal artery (p less than 0.05). The relative risk (and 95% confidence interval) of developing internal pudendal artery atherosclerosis for each 10 pack-years smoked was 1.31 (1.05 to 1.64). A third analysis investigated the potential interactive effects of cigarette smoking and pelvic or perineal trauma. A significantly higher incidence (p less than 0.05) of cavernous artery atherosclerosis was found among smokers with a history of chronic perineal trauma (33 patients) compared to nonsmokers with a similar history (25 patients). The findings of this study indicate that cigarette smoking is an independent risk factor in the development of atherosclerotic lesions in the internal pudendal and common penile arteries of young impotent men. Cigarette smoking appears to predispose these patients to early atherosclerotic lesions in the cavernous artery following chronic perineal trauma.

Adolescent↗
PubMed1991

Recurrent prolonged erections and priapism as a sequela of priapism: pathophysiology and management.

Veno-occlusive priapism may be associated with prolonged corporeal ischemia, subsequent fibrosis of the corpora and impotence. We report on 6 patients who presented with an unusual sequela of veno-occlusive priapism, recurrent episodes of prolonged erections or priapism. In all cases the subsequent episodes were idiopathic and veno-occlusive, occurred with a frequency ranging from several times per day to once per month and were symptomatically disabling. Pharmacocavernosometry ruled out mechanical occlusion of corporeal venous drainage by demonstrating elevated flows to maintain intracavernosal pressures following smooth muscle contraction and markedly decreased flow rates following smooth muscle relaxation. Treatment of the recurrent episodes with intracavernous self-injection of phenylephrine resulted in successful detumescence. The use of oral phenylpropanolamine reduced the frequency and duration of the recurrences, and markedly reduced the need for adrenergic self-injection. It is proposed that this syndrome may develop secondary to the initial ischemic episode, resulting in a functional alteration of the adrenergic and/or endothelial-mediated mechanisms that control penile tumescence and maintain penile flaccidity.

Administration, Oral↗
PubMed1991

Trabecular smooth muscle modulates the capacitor function of the penis. Studies on a rabbit model.

We investigated the role of trabecular smooth muscle tone in regulation of intracavernosal pressure, venous outflow resistance, and penile capacitance. In an isolated rabbit whole penis model, corpora cavernosa were infused with either contracting (high K(+)-norepinephrine combination) or relaxing (no added Ca(2+)-papaverine combination) physiological salt solutions while intracavernosal pressure was recorded. An infusion pump regulated by an intracavernosal pressure feedback mechanism enabled the measurement of flow necessary to maintain intracavernosal pressures at 30, 60, 90, 120, and 150 mmHg under steady-state conditions (inflow = outflow). These experiments allowed resistance to outflow from corpora to be calculated when trabecular smooth muscle was either constricted or relaxed. Decay in intracavernosal pressure over time from various predetermined intracavernosal pressures (150, 120, 90, 60, and 30 mmHg) was studied under conditions of zero inflow following contraction or relaxation of trabecular smooth muscle. This permitted calculation of the time constant, which together with the outflow resistance, permitted the calculation of penile capacitance. When smooth muscle is relaxed, venous outflow resistance is high, constant, and independent of intracavernosal pressure. Furthermore, relaxation of smooth muscle allows expansion of corpora with accumulation of volume under pressure, enabling the penis to act as a capacitor. This capacitor function is limited in the presence of constant high outflow resistance by stiffness of the fibroelastic elements of penis, tunica, and fibroelastic frame, which exhibit nonlinear deflection trends. Analysis of these variables has led us to propose a model for penile erection.

Animals↗
PubMed1991

Endothelin: localization, synthesis, activity, and receptor types in human penile corpus cavernosum.

The localization, synthesis, and activity of endothelin and the receptor types mediating its effects in penile corpus cavernosum were investigated in whole tissue and in cultured cells derived from this tissue. With immunocytochemistry, utilizing an antiendothelin 1 (ET-1) monoclonal antibody, endothelin-like immunoreactivity was localized intensely in the endothelium and to a lesser degree in the trabecular smooth muscle. Human corpus cavernosum endothelial cells in culture expressed preproendothelin 1 mRNA, as determined by Northern blot analysis. Significant amounts of endothelin-like immunoreactivity were measured by radioimmunoassay in the supernatants of corpus cavernosum endothelial cells in culture. Endothelins are potent constrictors and caused long-lasting contractions of corporeal strips in organ chambers. Equilibrium binding analysis of endothelins to their receptor sites revealed high-affinity, specific, and saturable binding of labeled endothelins to corporeal membranes. Competition binding experiments demonstrated receptors with high affinity for ET-1 and -2 and low affinity for ET-3 and another, less abundant, set of receptors with high affinity for ET-1, -2, and -3. Affinity labeling of endothelins to corporeal membranes, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, revealed that ET-1 and -2 cross-linked specifically to three different molecular mass components (75, 52, and 34 kDa). ET-3 bound only to the 34-kDa component. It is concluded that human corpus cavernosum endothelium has the ability to synthesize and release endothelin, that endothelins contract corporeal smooth muscle, and that at least two distinct endothelin receptors may exist and are differentiated by their affinity for ET-3.

Affinity Labels↗
PubMed1991

A nitric oxide-like factor mediates nonadrenergic-noncholinergic neurogenic relaxation of penile corpus cavernosum smooth muscle.

This study was initiated to characterize nonadrenergic-noncholinergic (NANC) inhibitory neurotransmission in penile corpus cavernosum. Using organ baths, isometric tension measurements were made in strips of human and rabbit corpus cavernosum. In examining endothelium-mediated responses, cumulative additions of exogenous acetylcholine elicited dose-dependent relaxations which were significantly reduced or completely inhibited in tissues treated with NG-monomethyl L-arginine (L-NMMA; an inhibitor of nitric oxide synthesis), oxyhemoglobin (a nitric oxide scavenger), or methylene blue (a guanylate cyclase blocker). Tissues exposed to hypoxic conditions (PO2 = 5-10 mmHg) also did not respond to exogenous acetylcholine. Mechanical removal of the endothelium in human corporal strips or in situ treatment of rabbit corpora with detergent blocked the relaxation to acetylcholine. Transmural electrical stimulation of corporal tissue strips denuded of functional endothelium, in the presence of adrenergic blockade with bretylium and muscarinic receptor blockade with atropine, caused frequency-dependent relaxation. This neurogenic relaxation was reduced or prevented by L-NMMA, oxyhemoglobin, methylene blue, and hypoxia. The effects of L-NMMA were reversed by L-arginine and the effects of hypoxia were readily reversed by normoxic conditions. Authentic, exogenous nitric oxide relaxed corporal strips which were contracted with adrenergic agonists and this effect was significantly inhibited by oxyhemoglobin. It is concluded that (a) endothelium-mediated responses of corpus cavernosum smooth muscle are mediated by a diffusible nitric oxide-like substance; (b) NANC neurogenic inhibitory responses do not require functional endothelium, and (c) nitric oxide, or a closely related substance, may act as an inhibitory neurotransmitter in penile corpus cavernosum smooth muscle.

Acetylcholine↗
PubMed1991

Evaluation of normal gestational sac growth: appearance of embryonic heartbeat and embryo body movements using the transvaginal technique.

A cross-sectional transvaginal ultrasound study was conducted in 137 normal pregnancies with gestational ages ranging from 5-12 weeks. Several biometric measurements were obtained throughout pregnancy, including the three diameters of the gestational sac, the crown-rump length, and the yolk sac. In addition, the appearance of the embryo heartbeat and embryo body movements were evaluated. Linear relationships were found between the mean gestational sac diameters and gestational age (r = 0.911; P less than .00001) and between mean gestational sac growth and crown-rump length growth (r = 0.926; P less than .0001). A gestational sac could be identified at 5 weeks' gestation; embryo heartbeat was imaged when the mean gestational sac diameter measured 2 cm, and embryo body movements could be seen when the mean gestational sac diameter reached 3 cm. In the present study, embryo heartbeat was identifiable after 6 weeks and 4 days with a sensitivity of 100%, specificity of 93.1%, positive predictive value of 96.9%, and negative predictive value of 100%. The embryo body movements, which were absent before 7 weeks' gestation, were observed after 8 weeks' gestation with a sensitivity of 100%, specificity of 92.8%, positive predictive value of 94.3%, and negative predictive value of 100%. With identification by transvaginal sonographic evaluation, the following can serve as markers of normal embryo growth: a mean gestational sac diameter greater than 2 cm in the presence of the embryo heartbeat, or a mean sac diameter measurement greater than 3 cm in the presence of embryo movement.

Extraembryonic Membranes↗
PubMed1990

Intraamniotic infection in the very early phase of the second trimester.

A total of 157 consecutive patients were studied in an effort to examine prospectively the incidence of asymptomatic intraamniotic infection in the early phase of the second trimester. All patients were referred for amniotic fluid karyotyping. In addition, the amniotic fluids were examined for Gram stain and were directly cultured on blood agar and MacConkey agar as well as in thioglycollate broth. We found positive amniotic fluid cultures in eight cases (5.09%); however, results of Gram stain examinations were negative in all amniotic fluid samples. The data indicate that there is no correlation between white blood cells in the amniotic fluid and positive amniotic fluid culture results. Only one pregnancy with positive amniotic fluid culture resulted in a septic abortion. Therefore we can suggest that intraamniotic infection can exist early in pregnancy, even with intact membranes, and in most cases without any clinical symptoms.

Abortion, Septic↗
PubMed1990

A vesicovaginal fistula and intravesical foreign body. A rare case of the neglected pessary.

A case of neglected pessary is presented. After erosion through the anterior vaginal and bladder walls the device came to rest entirely within the bladder. Surgical management of removal of the pessary and repair of the resulting vesicovaginal fistula are described. Appropriate use of supportive pessaries as well as complications of misuse and neglect are discussed.

Aged↗