A neuroanatomical comparison of humans and spotted hyena, a natural animal model for common urogenital sinus: clinical reflections on feminizing genitoplasty

PURPOSE: Surgical treatment of the common urogenital sinus phallus has been one of the most challenging areas in pediatric urology. To better understand the neuroanatomy of the common urogenital sinus phallus, we evaluated an animal model naturally having this condition, the spotted hyena, Crocuta crocuta. We compared the neuroanatomy of male and female humans and spotted hyenas using anatomical, immunohistochemical and 3D reconstruction techniques. We also examined the implications of the pattern of clitoral innervation for the unique challenges faced by female spotted hyenas, the only extant species of mammal that mates and gives birth through the clitoris. MATERIALS AND METHODS: Three adult male and 3 female spotted hyenas were studied. With the animals under anesthesia gross anatomical examination was performed before and after artificial erection. Histological analysis was performed on one 95-day fetal male and female spotted hyena specimens, and on 18 human male and female fetal external genitalia specimens using antibodies raised against the neuronal marker S-100. Three-dimensional computer reconstruction using serial sections allowed analysis of the neuroanatomy of the penis, clitoris and common urogenital sinus of the fetal spotted hyena and human. RESULTS: Compared to other mammals, the clitoris and penis of spotted hyenas were remarkably similar in size and configuration in the flaccid and erect states. Male and female hyenas had a single opening on the tip of the glans penis/clitoris. The basic anatomical structures of the corporeal bodies in both sexes of humans and spotted hyenas were similar. As in humans, the dorsal nerve distribution was unique in being devoid of nerves at the 12 o'clock position in the penis and clitoris of the spotted hyena. Dorsal nerves of the penis/clitoris in humans and male spotted hyenas tracked along both sides of the corporeal body to the corpus spongiosum at the 5 and 7 o'clock positions. The dorsal nerves penetrated the corporeal body and distally the glans in the hyena. In female hyenas the dorsal nerves fanned out laterally on the clitoral body. Glans morphology was different in appearance in both sexes, being wide and blunt in the female and tapered in the male. CONCLUSIONS: The neuroanatomy of the male and female external genitalia in the spotted hyena, Crocuta crocuta, although grossly similar, has distinct anatomical and functional characteristics. The clitoris of the spotted hyena is a classic example of a natural animal model of a common urogenital sinus. The neuroanatomical characteristics of the spotted hyena may be a useful model to simulate the anatomy of common urogenital sinus anomaly in humans.     

Magnetic resonance imaging of the brainstem: normal structure and basic functional anatomy

Normal structure and basic functional anatomy of the brainstem were studied using anatomic sections obtained with a cryomicrotome whole-organ sectioning technique. Major tracts and nuclei were identified and their function summarized. Magnetic resonance imaging of the brainstem was performed on 10 normal volunteers. By comparing these images with the corresponding anatomic sections, normal structures, including major tracts and nuclei, were identified. Knowledge of location and function of clinically important brainstem nuclei and tracts is necessary for optimal magnetic resonance image interpretation.     

Helping Teachers Help Children With Cancer: A Workshop for School Personnel

Even though survival rates have improved dramatically, childhood cancer remains a life-threatening illness How can patients and families be helped to deal with the chronic stressors inherent in such a disease? This article focuses on one aspect of this question promoting positive experiences at school It describes a workshop offered for the purpose of providing information about childhood cancer to public and private school teachers in Charleston, South Carolina Pre- and post-workshop assessments were done of the participants' knowledge of medical facts about childhood cancer, their attitudes toward children with cancer, their knowledge of the emotional impact of cancer on families, and their beliefs about how they would respond to a student with cancer The results are examined in terms of changes in the teachers' attitudes and objective knowledge and factors which predict the pre-workshop levels of those variables Finally, implications of the results are examined, in light of the utility and effectiveness of such an intervention as a means of "primary prevention".     

Mental health systems and services in the United States

This paper discusses mental health policies, mental health services, awareness of these services, the evaluation of such services and how mental health care is financed in this country. Dr. David Baskin, Director of Evaluation and Research at the Bronx-Lebanon Hospital Center/Crotona Park Community Mental Health Center, a member of the faculty of the Albert Einstein College of Medicine, has lectured on the epidemiology of mental disorders and conducted numerous research projects in the field of mental health.     

Neoplasms of transitional cell origin in first twenty years of life

Three cases of transitional cell carcinoma in childhood are reported, including 1 patient with multiple tumors believed to be the second such case reported. The three cases are discussed in relation to cases previously described in this age group. Transitional cell tumors in the first two decades are then compared with a similar group of low-grade tumors in adults which indicate a much more benign behavior of this type tumor in the younger age group.     

Somatosensory influence on corticomotor evoked potentials

The clinical utility of corticomotor evoked potentials (CMEPs) as a method of evaluating and monitoring patients with spinal cord disorders is being intensively studied. Relatively few neuronal mechanisms responsible for waveform production are clearly known. Although CMEP components are dependent upon activity carried in descending motor pathways, somatosensory information can influence the basic waveform structure. By stimulating peripheral afferent fibers at varying frequencies, intensities, and trains, two CMEP component groups were identified based on latency. The configuration of the short-latency waveforms was influenced primarily by large-diameter afferents. Long-latency waveforms were altered primarily by small-diameter afferents. The present investigation describes both segmental and suprasegmental modification of CMEP characteristics based on afferent fiber group stimulation. If both motor and sensory systems can be accurately assessed, the clinical applications of CMEPs are considerably enhanced.     

Taking pressure off the heart: the ins and outs of atrophic remodelling

Our work on atrophic remodelling of the heart has led us to appreciate the simple principles in biology: (i) the dynamic nature of intracellular protein turnover, (ii) the return to the foetal gene programme when the heart remodels, and (iii) the adaptive changes of cardiac metabolism. Although the molecular mechanisms of cardiac hypertrophy are many, much less is known regarding the molecular mechanisms of cardiac atrophy. We state the case that knowing more about mechanisms of atrophic remodelling may provide insights into cellular consequences of metabolic and haemodynamic unloading of the stressed heart. Overall we strive to find an answer to the question: 'What makes the failing heart shrink and become stronger?' We speculate that signals arising from intermediary metabolism of energy-providing substrates are likely candidates.