A functional and clinical reinterpretation of human perineal neuromuscular anatomy: Application to sexual function and continence

Modern anatomical and surgical references illustrate perineal muscles all innervated by branches of the pudendal nerve but still organized into anatomically distinct urogenital and anal triangles with muscles inserting onto a central perineal body. However, these conflict with the anatomy commonly encountered during dissection. We used dissections of 43 human cadavers to characterize the anatomical organization of the human perineum and compare our findings to standard references. We found bulbospongiosus and the superficial portion of the external anal sphincter (EAS) were continuous anatomically with a common innervation in 92.3% of specimens. The superficial transverse perineal muscle inserted anterior and lateral to the midline, interdigitating with bulbospongiosus. The three EAS subdivisions were anatomically discontinuous. Additionally, in 89.2% of our sample the inferior rectal nerve emerged as a branch of S3 and S4 distinct from the pudendal nerve and innervated only the subcutaneous EAS. Branches of the perineal nerve innervated bulbospongiosus and the superficial EAS and nerve to levator ani innervated the deep EAS. In conclusion, we empirically demonstrate important and clinically relevant differences with perineal anatomy commonly described in standard texts. First, independent innervation to the three portions of EAS suggests the potential for functional independence. Second, neuromuscular continuity between bulbospongiosus and superficial EAS suggests the possibility of shared or overlapping function of the urogenital and anal triangles. Clin. Anat. 29:1053–1058, 2016. © 2016 Wiley Periodicals, Inc.     

The Effect of Biphasic Defibrillation on the Immediate Pacing Threshold of a Dedicated Bipolar, Steroid-Eluting Lead

It is apparent that pacing threshold increases following an ICD shock, although the degree of change observed is dependent on the method used to assess pacing and the lead design used. We previously demonstrated a rise in postshock pacing threshold using a lead with integrated bipolar pacing in which the distal shocking coil also serves as the pacing anode. In this study, we sought to investigate whether the postshock pacing threshold increased significantly in an endocardial, steroid-eluting lead with dedicated bipolar pacing electrodes. Twenty patients (16 men, 4 women; median age 73, ejection fraction [EF] 0.17-0.58) were studied during pectoral ICD implantation (Medtronic active can model 7221Cx or 7223Cx with model 6932-65 lead). The diastolic pulse width pacing threshold at 1 or 2 V was determined. Pacing rate was set > or = 100/min at twice diastolic threshold output to assess pacing immediately following the first DFT test shock. For subsequent shocks, the output was adjusted to establish postshock thresholds as 1, 2, 3, or 4 times the diastolic threshold. The postshock threshold was defined as the output yielding 100% capture > or = 2.5 seconds following a shock. In 8 of 20 patients (ratio 0.40 +/- 0.11), a rise in the post-shock threshold was shown by failure of consistent capture when pacing at 2 times diastolic threshold > or = 2.5 seconds after a DFT test shock. Two of these patients failed at 3 times threshold, but none failed at 4 x threshold. Five of 12 patients with successful capture of 2 times threshold failed to capture at threshold. The postshock threshold increased by a mean factor of 2.83 +/- 0.83 in the group of patients with a threshold rise. Following ICD shock in an active can, steroid-eluting lead system with dedicated bipolar pacing, the post-shock threshold increases significantly. Our studies suggest a need for postshock pacing to be set at least 4 x threshold regardless of the lead design.     

Radiofrequency Catheter Ablation of an Incessant Supraventricular Tachycardia Initiated by a Hisian Parasystole

The coexistence of a pamsystolic focus, tachycardia dependent right bundle branch aberrancy, and an AV accessory pathway is reported here. This condition was present in a 40-year-old man, which led to an incessant AV reciprocating tachycardia. Further electrophysiological study revealed that the parasystolic focus was located somewhere in the His bundle; endocardial mapping disclosed a right posterior accessory pathway. Radiofrequency current was delivered at the atrial level of the right posterolateral AV groove and successfully ablated the accessory pathway, leading to a dramatic improvement in cardiac function. In conclusion, the recognition of the electrophysiological mechanism of incessant Supraventricular tachycardia was of crucial importance for the therapy decision. A definitive intervention using radiofrequency catheter ablation should be considered early and not postponed in patients with tachycardia-induced cardiomyopathy.     

Diabetes Mellitus as a Risk Factor for Development of Vulnerable (Unstable) Coronary Plaque: A Review of Possible Mechanisms

The prevalence of early and severe atherosclerotic coronary disease is much higher in diabetic patients than in their nondiabetic counterparts. The incidence of acute coronary syndrome is also disproportionately higher in this population. This difference has generally been attributed to a much higher prevalence of traditional risk factors such as hypertension and dyslipidemias in diabetic patients; however, a clear explanation is yet to be found. Vascular injury and growth factors are increased in these individuals. Metabolic and biochemical abnormalities such as glycosylation and oxidation of low density lipoprotein (LDL) and the formation of "large" very low density lipoprotein (VLDL) promote the accumulation of monocytes and macrophages, leading to the formation of foam cells. Glycosylation of high density lipoprotein (HDL) impairs its antiatherogenic action. These abnormalities may enhance the extracellular (core) lipid content of the atherosclerotic plaque, rendering it softer. An augmented inflammatory response also appears to take place in the atherosclerotic plaque of diabetic patients. There is a strong chemotaxis for monocytes and macrophages mediated by glycoxidation. These cells induce the secretion of interleukin-1 and cachectin/tumor necrosis factor, which in turn inhibit nitric oxide activity, leading to detrimental action of mast cells. Diabetic patients also have an enhanced vasoconstrictive response. Significant platelet, coagulation, and fibrinolytic abnormalities are also present in these individuals, which favor a relatively hypercoagulable state. Plaque stress due to enhanced tensile and compression forces appears to be increased in diabetic patients.     

ITRACONAZOLE IN THE TREAMENT OF CHROMOBLASTOMYCOSIS DUE TO FONSECAEA PEDROSOI

The efficacy and tolerability of itraconazole in chromoblastomycosis due to Fonsecaea pedrosoi were evaluated in a non-comparative open clinical trial in 19 Brazilian patients with histopathologically and mycologically proven active chromoblastomycosis. Patients were classified in terms of severity and received itraconazole at the dosage of 200 to 400 mg per day until previously described criteria of cure have been reached. Clinical, mycologic, histopathologic, and laboratory evaluations were performed before, during, and after therapy. The plasma levels of itraconazole and the in vitro susceptibility of the isolates were determined in 15 cases. Clinical and biologic cure were achieved by eight patients (42%) having mild to moderate disease, after a mean duration of therapy of 7.2 months (3.2-29.6 months). Sterile scarred lesions were observed in a post-therapy follow-up lasting on average 9.6 months that was carried out in this subgroup. Clinical cure alone occurred after a mean period of 25.1 months of treatment (16-30.5 months) in seven patients (36%) with moderate to severe disease. Finally, clinical improvement was obtained in four patients (21%) with severe lesions after a mean treatment time of 17.6 months (10.7-22.5 months). All patients responded favorably to itraconazole therapy. No significant side effects nor biochemical alteration during this trial were important enough to interrupt the treatment. Our results support those of previous trials, suggesting that itraconazole is an effective compound against chromoblastomycosis due to Fonsecaea pedrosoi.     

The Architecture of the Atrial Musculature Between the Orifice of the Inferior Caval Vein and the Tricuspid Valve: The Anatomy of the Isthmus

Anatomy of Electrophysiologic Isthmus. Introduction : Electrophysiologists recognize a so-called "isthmus" in the right atrium through which passes the reentrant circuit of common atrial flutter. Ablative lesions placed in this narrow channel have proved effective in breaking the circuit. To the best of our knowledge, however, no study has been performed to establish the arrangement and orientation of the atrial myocardial fibers in this crucial area.
Methods and Results : We examined 28 normal heart specimens, identifying a quadrilateral area composed of three morphologic sectors between the inferior caval vein and the tricuspid valve confluent superiorly with the triangle of Koch. Within this quadrilateral, there are constant recesses, or sinuses, inferior and lateral to the orifice of the coronary sinus. The inferior isthmus measured an average of 31 ± 4 mm (range 19 to 40). Gross examination identified marked differences in the atrial wall forming the quadrilateral. A smooth anterior component forming the vestibule of the tricuspid valve was found in all the hearts, but variations in the remaining sectors were seen in ten specimens. The usually membranous posterior sector was noticeably muscular in three specimens, while the middle, trabecular sector was more membranous in five specimens. We demonstrated the orientation of the subendocardial atrial fibers by dissection in 14 specimens, revealing a relatively constant overall pattern in eight specimens and variations in fiber orientation in the remaining specimens.
Conclusion : There are considerable anatomic variations in the atrial wall that comprises the so-called isthmus. The presence of recesses and membranous areas in some hearts and the variations in arrangement of the subendocardial fibers are relevant in improving understanding of conduction in this area.     

Immunohistochemical Localization of Gap Junction Protein Channels in Hamster Sinoatrial Node in Correlation with Electrophysiologic Mapping of the Pacemaker Region

Gap Junction Proteins in the Sinoatrial Node. Introduction: Gap junction proteins are thought to form the low resistance pathways that connect neighboring cells within the sinoatrial node, and to mediate pacemaker synchronization.
Methods and Results: We have carried out microelectrode mapping experiments of the hamster sinoatrial region to localize the primary pacemaker area for subsequent light, electron, and immunofluorescence microscopic studies aimed at testing the hypothesis that the major cardiac gap junction protein (connexin43) is present in such an area. The site of earliest activation is unifocal and the pattern of activation, obtained In multiple sequential microelectrode recordings of the Sinoatrial region, is qualitatively similar to that previously described for other species. However, quantitatively, the impulse transmission time from the primary pacemaker area to the crista (sulcus) terminal's in the hamster sinoatrial node is about 50% briefer than that of the guinea pig and five times faster than that of the rabbit. Immunolocalization studies in the hamster sinoatrial node using anti-connexin43 antisera demonstrated specific staining at the areas of cell-to-cell apposition and suggested that the apparently high degree of electrical coupling in this tissue is the result of abundant connexin43 expression. The immunofluorescence data were supported by light microscopic studies, which demonstrated the typical morphologic characteristics of sinus nodal cells in the pacemaker area. In addition, an electron microscopic study of the sinoatrial region revealed the presence of gap junctions in the junctional complex at areas of cell-to-cell contact.
Conclusion: Our results demonstrate that cells in the sinoatrial region of the hamster heart are electrically well coupled and strongly suggest that such coupling is mediated by gap junctional channels formed by connexin43.     

Reproductive Toxicology of Aluminum in Male Mice

The reproductive toxicology of aluminum was studied in mice.Adult male mice were treated intraperitoneally with aluminumnitrate at doses of 0, 50, 100, and 200 mg/kg/day for 4 weeksbefore mating with untreated females. Decreased body weightwas seen in all aluminum-treated groups. Decreased pregnancyrate was observed in the females mated with males previouslytreated with 100 or 200 mg/kg/day of aluminum nitrate. High-dosemale mice showed significantly decreased testicular and epididymalweights, as well as significant decreases in testicular andspermatid counts and epididymal sperm counts. Spermatid countswere also reduced at 100 mg/kg/day. However, the sperm motilitywas unaffected, and the percentages of morphological normalspermatozoa in all mice exposed to aluminum were comparableto the values in control mice. Histological changes, includingnecrosis of spermatocytes/spermatids, were observed in the testesof male mice treated with 100 and 200 mg/kg/day of aluminumnitrate, whereas the tubu lar diameters were unaffected by aluminumadministration. The current study demonstrates adverse effectsof parenteral aluminum exposure on the mouse male reproductivesystem. The "no observable adverse effect level" (NOAEL) was50 mg/kg/day.