Effect of insulin treatment on tissue size of the genitourinary tract in BB rats with spontaneously developed and streptozotocin-induced diabetes

To examine the differences between spontaneous and streptozotocin (STZ)-induced diabetes, four parallel studies were performed; three studies of diabetes-prone BB (BBDP/Wor) rats maintained for 8, 16, and 32 weeks and one study of STZ-injected diabetes-resistant BB (BBDR/Wor) rats maintained for 32 weeks. Each diabetic study has three groups of rats: a control group; a euglycemic group, which received sufficient amounts of insulin; and a hyperglycemic group, which received a suboptimal dose of insulin. The extent of tissue weight changes was generally shown to be less dramatic in the euglycemic diabetic than in the hyperglycemic diabetic rats. STZ-induced diabetes increased the bladder weight more dramatically (up to 3-fold) than did spontaneous diabetes (up to 2-fold). Furthermore, a significant decrease in the size of the adrenal gland (20%) and testis (10%) is observed only with spontaneous diabetes, whereas a significant decrease in the size of the ventral prostate (30%) is observed only with STZ-induced diabetes, although the serum testosterone levels are similar in both groups. Our data demonstrate that there are differences in the effect of insulin treatment on the tissue size of the genitourinary tract between spontaneously developed and streptozotocin-induced diabetes in BB rats.

Usefulness of myocardial ischemia as predictor of training effect in cardiac rehabilitation after acute myocardial infarction or coronary artery bypass grafting

Exercise capacity increases to a variable degree in coronary patients during cardiac rehabilitation. The effect of baseline exercise-induced ischemia on the response to a 12-week conditioning program was evaluated in 106 coronary patients. The magnitude of exercise conditioning response was greater in nonischemic patients than in ischemic patients, with maximal exercise intensity increasing 69 versus 50% (7.2 to 12.1 vs 7.1 to 10.6 METs) (p less than 0.05) and maximal oxygen consumption increasing 28 versus 10% (23.1 to 29.6 vs 23.0 to 25.4 cc/kg/min) (p less than 0.05). Markers of conditioning during submaximal exercise such as heart rate and heart rate-systolic blood pressure product were similarly reduced in both groups. The groups did not differ by age, diagnosis, resting ejection fraction, incidence of beta-blocker use, maximal exercise capacity, maximal exercise heart rate, blood pressure or intensity of actual exercise training. These results suggest that exercise-induced ischemia alters the stimulus to adapt to exercise training.

Reversibility of diabetes- and diuresis-induced alterations in rat bladder dome muscarinic receptors

Previous studies from our laboratory demonstrated that 8 weeks of streptozocin (STZ)-induced diabetes and sucrose-fed diuresis resulted in increases in the density of muscarinic receptors in rat bladder dome and that early insulin treatment (started 3 days after the onset of diabetes) prevented the diabetes-induced upregulation (J Pharmacol Exp Ther 248:81-88, 1989; Diabetes 40: 1150-1156, 1991; J Urol 147:760-763, 1992). To determine whether diabetes- and diuresis-induced alterations in muscarinic receptors in rat bladder dome are reversible, we administered insulin (beginning 8 weeks after the onset of diabetes) or removed sucrose from drinking water of diuretic rats (beginning 8 weeks after the onset of diuresis). Five groups of rats were maintained for 16 weeks: 1) STZ-induced diabetic rats (65 mg/kg intravenously); 2) insulin-treated diabetic rats (5-8 U/day insulin subcutaneously beginning 8 weeks after the onset of diabetes); 3) sucrose-fed diuretic rats (5% sucrose in drinking water throughout 16 weeks); 4) sucrose-removed rats (sucrose withdrawn from drinking water after 8 weeks of the sucrose-induced diuretic state); and 5) age-matched control rats. Radioligand receptor binding experiments with [3H]quinuclidinyl benzilate showed an increase in the density of muscarinic receptors in bladder dome of diabetic and sucrose-fed rats compared with age-matched control rats. Removing the 5% sucrose from the drinking water of diuretic rats reversed the increased water intake and urine output, decreased the bladder hypertrophy that accompanied the diuretic state, and corrected the upregulation of the muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

CLINICAL AND HISTOLOGICAL SIGNIFICANCE OF THE TESTICULAR REMNANT FOUND ON INGUINAL EXPLORATION AFTER DIAGNOSTIC LAPAROSCOPY IN THE ABSENCE OF A PATENT PROCESSUS VAGINALIS

PURPOSE

We reviewed the histological findings of cord structures excised at inguinal exploration after diagnostic laparoscopy in patients with a nonpalpable testis with the vas deferens and spermatic vessels exiting the internal inguinal ring in the absence of a patent processus vaginalis.

MATERIALS AND METHODS

A retrospective review of 809 laparoscopic explorations for nonpalpable testes between 1981 and 2003 was conducted. The histological findings of the excised remnants of those patients with a closed processus vaginalis were reviewed.

RESULTS

A total of 110 patients underwent excision of a testicular remnant at inguinal exploration in association with a closed processus vaginalis. Of the specimens 31 (28%) were on the right side and 79 (72%) were on the left side. The incidence of viable germ cell elements was 8 of 110 (7%). The presence of hemosiderin, calcification and fibrosis was identified in all 8 remnants with viable germ cell elements.

CONCLUSIONS

The incidence of viable germ cell elements in the excised remnant when the vas deferens and spermatic vessels are identified exiting a closed internal ring in patients with a nonpalpable testis is 7%. To our knowledge no prior study has evaluated the incidence of viable germ cell elements in remnants associated with a closed internal inguinal ring. Based on these findings, we advocate inguinal exploration and excision of testicular remnants in these patients.

Pacemaker activity in the upper urinary tract

Ureteral peristaltic activity begins with the origin of electrical activity at pacemaker sites. These sites are located in the proximal portion of the urinary collecting system. The 'atypical' smooth muscle cells at these sites fire 'pacemaker' potentials at a frequency higher than the 'driven' action potentials recorded from typical smooth muscle cells. In contrast to typical smooth muscle cells, these atypical pacemaker cells have less than 40% of their cellular area occupied by contractile filaments and demonstrate a sparse immunoreactivity for alpha-smooth muscle actin. Expression of c-Kit, a tyrosine kinase receptor, correlates with the onset of organized ureteral peristalsis in the embryo. Capsaicin-sensitive sensory afferents and the endogenous release of tachykinins and prostaglandins are involved in the maintenance of normal ureteral peristalsis.

Regulation of cyclic nucleotides in the urinary tract

Cyclic nucleotide levels are controlled through their synthesis from nucleotide triphosphates by cyclases and their degradation to 5'-monophosphates by phosphodiesterases (PDEs). Components controlling cyclic AMP-induced relaxation in the urinary tract include receptors, inhibitory and stimulatory G-proteins, isoforms of adenylyl cyclase and PDEs. The responsiveness of PDEs to a variety of physiological challenges is related to the presence of multiple families of isoenzymes with specific localization within tissues and within cells. At least 11 families of PDEs encode more than 50 PDE proteins produced in mammalian cells. In the urinary tract, characterization of PDE isoforms has lagged behind other systems and much of the literature was published prior to identification of PDE7, 8, 9, 10, 11. Specific PDE inhibitors regulate smooth muscle function in the bladder, urethra, prostate and ureter. The pharmacological potential of these inhibitors may include treatment of urge incontinence and the low compliance bladder, and treatment of prostate cancer. G-proteins also regulate cyclic AMP production. Changes in specific G- protein isoforms with aging, most prominently Gialpha2, cause decreased relaxation response in the aging bladder. As we have seen here with aging and certainly in other disease processes, levels of the components of adenylyl cyclase/phosphodiesterase/protein kinase can change and thus affect the relaxation response. By exploitation of differences in PDE expression in disease, such as the overexpression of PDEs in cancer, treatment options may present themselves.

Differential regulation of EHD3 in human and mammalian heart failure

Electrical and structural remodeling during the progression of cardiovascular disease is associated with adverse outcomes subjecting affected patients to overt heart failure (HF) and/or sudden death. Dysfunction in integral membrane protein trafficking has long been linked with maladaptive electrical remodeling. However, little is known regarding the molecular identity or function of these intracellular targeting pathways in the heart. Eps15 homology domain-containing (EHD) gene products (EHD1-4) are polypeptides linked with endosomal trafficking, membrane protein recycling, and lipid homeostasis in a wide variety of cell types. EHD3 was recently established as a critical mediator of membrane protein trafficking in the heart. Here, we investigate the potential link between EHD3 function and heart disease. Using four different HF models including ischemic rat heart, pressure overloaded mouse heart, chronic pacing-induced canine heart, and non-ischemic failing human myocardium we provide the first evidence that EHD3 levels are consistently increased in HF. Notably, the expression of the Na/Ca exchanger (NCX1), targeted by EHD3 in heart is similarly elevated in HF. Finally, we identify a molecular pathway for EHD3 regulation in heart failure downstream of reactive oxygen species and angiotensin II signaling. Together, our new data identify EHD3 as a previously unrecognized component of the cardiac remodeling pathway.

Postmyocardial infarction remodeling and coronary reserve: effects of ivabradine and beta blockade therapy

We compared the effects of heart rate reduction (HRR) by the hyperpolarization-activated pacemaker current (I(f)) channel inhibitor ivabradine (MI+Iva) and the beta(1)-blocker atenolol (MI+Aten) on ventricular remodeling and perfusion after myocardial infarction (MI) in middle-aged (12 mo) Sprague-Dawley rats. Mean HRR was virtually identical in the two treated groups (19%). Four weeks after coronary artery ligation, maximal myocardial perfusion fell in the MI group but was preserved in infarcted rats treated with either Iva or Aten. However, coronary reserve in the remodeled hearts was preserved only with Iva, since Aten treatment elevated baseline perfusion in response to a higher wall stress. The higher maximal perfusion noted in the two treated groups was not due to arteriogenesis or angiogenesis. Plasma levels of angiotensin (ANG) II and myocardial ANG type 1 (AT(1)) receptor and transforming growth factor (TGF)-beta1 were reduced during the first week of treatment by both Iva and Aten. Moreover, treatment also reduced arteriolar perivascular collagen density. Despite these similar effects of Iva and Aten on vascularity and ANG II, Iva, but not Aten, attenuated the decline in ejection fraction and lowered left ventricular (LV) end-diastolic volume (LVEDV)-to-LV mass ratio, determined by echocardiography. In conclusion, 1) Iva has advantages over Aten in postinfarction therapy that are not due to differential effects of the drugs on heart rate, and 2) age limits growth factor upregulation, angiogenesis, and arteriogenesis in the postinfarcted heart.

Brain TACE (Tumor Necrosis Factor-α-Converting Enzyme) Contributes to Sympathetic Excitation in Heart Failure Rats

TNF-α (tumor necrosis factor-α) is initially synthesized as a transmembrane protein that is cleaved by TACE (TNF-α-converting enzyme) to release soluble TNF-α. The elevated level of TNF-α in the brain and circulation in heart failure (HF) suggests an increase in the TACE-mediated ectodomain shedding process. The present study sought to determine whether TACE is upregulated in cardiovascular/autonomic brain regions like subfornical organ and hypothalamic paraventricular nucleus in rats with ischemia-induced HF and whether TACE plays a role in TNF-α-driven sympathetic excitation. We found that TACE was expressed throughout the subfornical organ and paraventricular nucleus, with significantly higher levels in HF than in sham-operated (Sham) rats. Intracerebroventricular injection of recombinant TACE induced a mild increase in blood pressure, heart rate, and renal sympathetic nerve activity that peaked at 15 to 20 minutes in both Sham and HF rats. HF rats had a secondary prolonged increase in these variables that was prevented by the TNF-α inhibitor SPD304. Intracerebroventricular administration of the TACE inhibitor TNF-alpha protease inhibitor 1 decreased blood pressure, heart rate, and renal sympathetic nerve activity in Sham and HF rats, with an exaggerated reduction in heart rate and renal sympathetic nerve activity in the HF rats. Direct microinjection of TACE or TNF-alpha protease inhibitor 1 into paraventricular nucleus or subfornical organ of Sham and HF rats elicited blood pressure, heart rate, and renal sympathetic nerve activity responses similar to intracerebroventricular TACE or TNF-alpha protease inhibitor 1. Intracerebroventricular infusion of Ang II (angiotensin II) and IL (interleukin)-1β increased TACE expression in subfornical organ and paraventricular nucleus of normal rats. These data suggest that a TACE-mediated increase in soluble TNF-α in the brain contributes to sympathetic excitation in HF.

Age-dependent changes in particulate and soluble guanylyl cyclase activities in urinary tract smooth muscle

Regional and age specific differences are observed in the sodium nitroprusside induced relaxation responses in the urinary tract. To clarify these differences, guanylyl cyclase activity is assayed in particulate and soluble fractions from the ureter, bladder dome, and urethra of young (11-18 days), adult (90-100 days), and old adult (2-3 years) guinea pigs. The rank order of soluble guanylyl cyclase activities is urethra = ureter > bladder dome with the largest decreases with aging occurring in the bladder. Atrial natriuretic factor (10(7) M) increases particulate guanylyl cyclase activity in the three tissues at all ages tested, with the activity being highest in the ureter. ATP (0.5 mM) activates particulate guanylyl cyclase in the ureter, bladder and urethra of old adult guinea pigs, and enhances atrial natriuretic factor induced activation of particulate guanylyl cyclase in all tissues and at all ages tested. The higher levels of soluble guanylyl cyclase activity in the urethra and ureter compared to the bladder parallel sodium nitroprusside induced relaxation in these tissues.

Physiology and evaluation of ureteropelvic junction obstruction

Ureteropelvic junction (UPJ) obstruction is not a single anatomic entity but rather a set of processes with multiple causes. In the obstructed system, histologic changes are apparent that have implications for healing. The role of crossing vessels In UPJ obstruction and its treatment is of growing interest. Various methods are available to assess the functional characteristics of the UPJ, of which the diuretic renogram, Whitaker perfusion test, and Doppler ultrasound resistive index may be the most useful. The treatment must be individualized according to the patient's symptoms, the status of renal function, and the potential complications of intervention.

Quantification of endothelins, their receptors, and endothelin-converting enzyme mRNAs in rat genitourinary tract using real-time RT-PCR

INTRODUCTION

Quantification of mRNA expression is essential for the assessment of endothelin (ET) receptor-mediated mechanisms. Recently, a novel technique for the determination of mRNA expression, termed real-time reverse transcription polymerase chain reaction (RT-PCR), has been developed. We therefore applied real-time PCR using SYBR Green I to quantify ET-1, ET-3, ET-converting enzyme-1 (ECE-1), and ETA and ETB receptor subtype mRNA expression in the rat genitourinary tract.

METHODS

The cDNA was synthesized by RT of RNA extracted from the rat bladder, ventral prostate, dorsolateral prostate, and vas deferens. All steps subsequent to the RT reaction were carried out by the thermal cycler/detector and computer-assisted programs processed a quantitative result.

RESULTS

Designing optimal primer sequences that minimized primer-dimer formation and adjusting annealing temperatures that prevented nonspecific product amplification have made it possible to identify a single peak in the melt curve and to obtain an appropriate standard curve for each gene transcript. In our experiments, input cDNA levels as low as 100 copies of the product could be detected.

DISCUSSION

We demonstrated that significant quantitative variations existed in the expression levels of ET-1, ET-3, ECE-1, and ETA and ETB receptor subtype mRNAs within a tissue and between different regions of the genitourinary tract and that the predominant expression of ETs and their receptor mRNAs in all tissues studied were ET-1 and the ETA receptor subtype, respectively.

Venographic localization of the non-palpable undescended testis in children

In cases of bilateral non-palpable undescended testes in which human chorionic gonadotropin stimulation has shown the presence of testicular tissue and in cases of unilateral non-palpable undescended testes selective transfemoral gonadal venography with a modified Seldinger technique has been used for the preoperative localization of the non-palpable testis. since the undescended testis may be located anywhere along the course of its embryologic descent, that is from the level of the renal fossa to its exit from the inguinal canal, preoperative localization will aid in the surgical management. Gonadal venography has proved to be accurate and safe, and has aided in the determination of the extent of surgical exploration in 9 children with 12 non-palpable undescended testes (6 right and 6 left).

Muscarinic receptors in diabetic rat prostate

To investigate the effects of experimentally-induced diabetes on prostatic muscarinic cholinergic receptors, the binding characteristics of [3H]quinuclidinyl benzilate ([3H]QNB) to prostatic membrane particulates were examined in four groups of rats: control, diabetic, diabetic insulin treated, and diabetic myo-inositol treated. Diabetes was induced by i.v. injection of streptozotocin (STZ), 65 mg/kg. Diabetic and diabetic myo-inositol-treated rats had hyperglycemia, hypoinsulinemia, glucosuria, polydipsia, and polyuria as well as significantly smaller prostates and lower body weights compared to control and diabetic insulin-treated animals. The densities of muscarinic receptors (Bmax) as determined by saturation studies with [3H]QNB in the prostatic plasma membranes of control, diabetic, diabetic insulin-treated and diabetic myo-inositol-treated rats were 80 +/- 8, 51 +/- 5, 78 +/- 3, and 47 +/- 7 fmol/mg of protein, respectively. [3H]QNB binding to muscarinic receptors was inhibited by muscarinic antagonists with the following rank order of Ki values: atropine much less than pirenzepine less than AF-DX 116. The pharmacological profile of the muscarinic receptors was similar in all groups examined and was consistent with the predominance of the M3 muscarinic receptor subtype in prostatic membrane particulates. Our data indicate that STZ-induced diabetes caused a variety of abnormalities including a down-regulation in the density of M3 muscarinic receptors in the rat prostate and that insulin, but not myo-inositol could prevent the development of these abnormalities.

Developmental changes in impulse conduction in the canine heart

We studied the age-related changes that occur in conduction in Purkinje fiber bundles (PF) from adult and 8-wk-old dogs. As PF are stretched, conduction velocity increases to a maximum when bundle length is approximately 1.5 times control. Conduction velocity in adult PF was significantly faster than that in 8-wk PF at all bundle lengths, the maximum being 2.32 +/- 0.45 m/s (mean +/- SD) in adult and 1.56 +/- 0.59 m/s in 8-wk-old dogs. At greater than 1.5 times control length, conduction velocity decreased, as did resting potential, action potential amplitude, and upstroke velocity. At 1.5 times control length, the ratio of PF to collagen in the bundles increased, and structural changes consistent with both unbuckling and unfolding of the cell membranes were seen. At greater degrees of stretch, cleft size diminished, and intracellular edema was noted. In sum, structural changes in cardiac PF can explain the changes in conduction velocity that occur with stretch. At all degrees of stretch, however, velocity is faster in PF from adult than from young dogs.

Quantitation of absolute regional myocardial perfusion using cine computed tomography

OBJECTIVES

The purpose of this study was to develop and test a method for quantitation of regional myocardial perfusion using cine computed tomography.

BACKGROUND

Cine computed tomography is a relatively new cardiac imaging technique with excellent temporal and spatial resolution. Application of this technique to the study of human coronary circulation could substantially broaden our knowledge of human cardiac pathophysiology. This goal has been previously approached with some success. However, no method to date has shown validated accuracy of regional perfusion measurements over the entire range of physiologically important flow states.

METHODS

Eight anesthetized dogs underwent thoracotomy for instrumentation. They were then studied during baseline flow conditions, after coronary vasodilation with intravenous dipyridamole and after coronary stenosis or occlusion. Regional myocardial perfusion was assessed by cine computed tomography using a method that includes estimates for myocardial blood volume and rate of myocardial enhancement after an aortic root contrast medium infusion. Measurements made nearly simultaneously by the radioactive microsphere method served as a reference standard.

RESULTS

A total of 32 perfusion conditions were studied with a range of 4 to 593 ml/min per 100 g. There was reasonable agreement between the two methods of measurement throughout the whole range of perfusion states: r = 0.97, regression slope 0.99, intercept 2 ml/min per 100 g. In zones not subserved by a stenosed or occluded artery, cine computed tomography accurately depicted perfusion homogeneity with a coefficient of variation of 13 +/- 1% (mean +/- SE) versus 11 +/- 1% for the microsphere method (p = NS).

CONCLUSIONS

Cine computed tomography is capable of providing accurate, quantitative assessment of regional myocardial perfusion over a broad range of perfusion states. This method, if extended to the study of humans, could enhance the understanding of disorders of the coronary circulation in human cardiovascular disease states.

Secondary bladder neck obstruction in patients with urethral valves: Treatment with phenoxybenzamine

Two cases are reported of functionally significant bladder neck obstruction following urethral valve fulguration which resulted in inability to void. Both patients responded to the administration of phenoxybenzamine, an alpha-adrenergic blocking agent. Treatment of patients with suspected bladder neck obstruction with this agent provides a reversible method of decreasing urethral resistance without the potentially harmful effects of surgical bladder neck revision.

Malignant rhabdoid tumor of the kidney in an adult

We report a case of rhabdoid tumor of the kidney in a 32-year-old white woman. This highly malignant tumor has been reported previously only in the pediatric age group. The clinical and pathological findings are discussed, and the literature is reviewed.

The multifunctional Ca²⁺/calmodulin-dependent kinase IIδ (CaMKIIδ) regulates arteriogenesis in a mouse model of flow-mediated remodeling

Objective

Sustained hemodynamic stress mediated by high blood flow promotes arteriogenesis, the outward remodeling of existing arteries. Here, we examined whether Ca²⁺/calmodulin-dependent kinase II (CaMKII) regulates arteriogenesis.

Methods and Results

Ligation of the left common carotid led to an increase in vessel diameter and perimeter of internal and external elastic lamina in the contralateral, right common carotid. Deletion of CaMKIIδ (CaMKIIδ−/−) abolished this outward remodeling. Carotid ligation increased CaMKII expression and was associated with oxidative activation of CaMKII in the adventitia and endothelium. Remodeling was abrogated in a knock-in model in which oxidative activation of CaMKII is abolished. Early after ligation, matrix metalloproteinase 9 (MMP9) was robustly expressed in the adventitia of right carotid arteries of WT but not CaMKIIδ−/− mice. MMP9 mainly colocalized with adventitial macrophages. In contrast, we did not observe an effect of CaMKIIδ deficiency on other proposed mediators of arteriogenesis such as expression of adhesion molecules or smooth muscle proliferation. Transplantation of WT bone marrow into CaMKIIδ−/− mice normalized flow-mediated remodeling.

Conclusion

CaMKIIδ is activated by oxidation under high blood flow conditions and is required for flow-mediated remodeling through a mechanism that includes increased MMP9 expression in bone marrow-derived cells invading the arterial wall.