Os penis of the rat. IV. The proximal growth cartilage

Histomorphological and histochemical aspects of the proximal cartilage of os penis and its surrounding perichondrium in 60 rats aged between 1 and 100 days are described. Comparisons at 11-14 days with the mandibular condylar cartilage reveal a slight difference in their general morphological composition. The developmental changes which take place in the os penis cartilage reveal histomorphologic events, some of which may be brought into agreement with previous observations of patterns of transformations of the bone. Observations on an age-dependent morphological appearance of the area adjacent to the proximal surface of the cartilage suggest certain agreements between the mandibular angular cartilage and the os penis cartilage. The study of phosphomonoesterases in the os penis cartilage and its perichondrium reveals significant, unexplained differences in the distribution of alkaline phosphatase between this cartilage and the mandibular condylar cartilage.     

The os penis of the rat. I. Phosphomonoesterases in its proximal growth cartilage

The distribution of reaction for acid and alkaline phosphatases in the proximal cartilage of the os penis and the mandibular condylar cartilage has been compared. The distribution of acid phosphatase in the two structures seems to be identical, whereas the distribution of alkaline phosphatase in the os penis cartilage seems to differ from that in the mandibular condylar cartilage and, by this, from all other studied growth cartilages.     

Androgen maintenance of erectile function in the rat penis.

Previous research has shown that the frequency and duration of penile erection is diminished after castration and that replacement with testosterone will restore the process. Using rats, the present study was designed to confirm that erection is androgen-dependent and to determine whether castration and androgen replacement affect the penile vascular smooth muscle responsiveness to vasoactive drugs. Blood pressure in the corpus cavernosum was measured directly during erections induced by electrical stimulation of the autonomic innervation of the penis. Maximal cavernosal pressure was markedly reduced after castration but was returned to normal levels if the castrated animals were treated with testosterone. Infusion of nitroglycerin (vasodilator) or phenylephrine (vasoconstrictor) resulted in a decline in cavernosal pressure in androgen-treated animals but not in castrated animals, even though the mean arterial blood pressure was strongly affected in all treatment groups by these drugs. When an inhibitor of nitric oxide synthesis was infused, cavernosal pressure was decreased in all groups, indicating that this substance is involved in penile erection. Taken together, these results show that androgens maintain the erectile process and may act specifically to support the responsiveness of the vascular smooth muscle to vasoactive drugs.     

The vasculature of the rat penis: a scanning electron microscopic and histologic study.

As a basis for understanding the mechanism of erection in an animal model frequently used in research in reproductive biology, the angioarchitecture of the penis of the rat has been described using scanning electron microscopy. Study of the penile vasculature of the rat indicates that the corpora cavernosa penis and the corpus spongiosum are independent erectile tissues, each with its own arterial and venous vessels. The large vascular spaces and abundant smooth muscle of the penile crura are compatible with its role in regulating blood flow to more distal penile tissues. Helicine arteries of the crura, but not the parent deep penile artery or arteries elsewhere, have muscular cushions in their walls. The venous drainage of the penile crura is via subtunical veins which are thought to be compressed during erection to elevate pressure within the penis. Large, paired cavernous veins drain the shaft of the penis. A unique method for inhibiting blood flow from the penis is indicated by the division of the cavernous veins into smaller channels prior to joining the subtunical venous plexus. Erectile tissue in the bifid origins of the corpus spongiosum has abundant cavernous muscle, while in the remainder of the corpus spongiosum little smooth muscle lines the cavernous spaces. The cavernous spaces on either side of the urethra coalesce to form vessels, each of which communicates with cavernous spaces in the glans. In addition, a bypass of the glans is effected by communication of these vessels directly with the deep dorsal vein. The apparent absence of muscular pads in vessels of the spongiosum, the relative paucity of cavernous smooth muscle, and the ample venous drainage provided by the deep dorsal vein may account for the lack of a venous occlusive mechanism similar to that of the corpora cavernosa penis.     

The elastic cartilage in the normal rat epiglottis

Summary Chondrocytes of the rat epiglottis contain large amounts of glycogen and lipids, which often make the cells resemble fat cells. The content of lipids is interpreted as being related to the function of the cells. The membranes of some of the large vacuoles are stained with ruthenium red. The cells give rise to long cytoplasmic processes. As in hyaline cartilage the intercellular substance consists of a fine network containing proteoglycan granules together with thicker cross striated fibers. Furthermore elastic fibers are found, consisting of amorphous and microfibrillar parts. In the matrix, both lysosome-like granules and more or less empty vesicles are observed. Accumulations of a finely particulate electron dense material and of a translucent amorphous material containing membrane bound granules are found in some lacunae situated in the outer part of the cartilage. These accumulations are possibly related to the development of collagenous and elastic fibers.     

The effect of glucose-1 phosphate calcium on the epiphyseal cartilage of the rat.

Electron microscopic investigations were carried out on the proximal tibial epiphyseal cartilage of albino rats treated with 2 mg G-1-P-Ca daily for one and three weeks. The treatment--enhanced the secretory activity of the upper cells of the zone of maturing cartilage with a consequential enlargement of the Golgi region, depletion of secretory products, and an increase in the number of microtubuli. --In addition, the treatment increased the number of matrix vesicles in the extracellular space showing incipient calcification. This findings confirm the earlier light micriscopic observation of the calcification stimulating effect of G-1-P-Ca.     

Lymphedema of the penis.

Lymphangiectomy with primary closure or skin grafting appears to be the treatment of choice for lymphedema of the penis. The method offers good cosmetic and functional results.     

An epidermal cyst of the penis after distal hypospadias surgery: a case report

Background

Epidermoid cyst is a benign tumor that can occur anywhere in the body but is rarely seen in the penis. Congenital and previous penile surgeries have been reported to be involved in the etiology of the disease, which is usually asymptomatic. Here we describe a case of a patient with a penile epidermoid cyst, which occurred in the circumcision line on the left side of his penis, and urethral dehiscence following hypospadias surgery.

Case summary

A 3-year-old white boy who underwent primary distal hypospadias surgery 1.5?years ago presented with a slowly growing mass in the left ventrolateral portion of the penile circumcision line and urethral dehiscence. The histology of the excised mass revealed an epidermal inclusion cyst. Since then, he has remained healthy.

Conclusions

Epidermal inclusion cyst as a complication of hypospadias surgery is a very rare situation. The diagnosis is made histologically and surgical excision is sufficient for treatment.

     

Ultrastructure of the developing fibrocartilage of the os penis of rat

Development of the fibrocartilage of the os penis of rat was studied by transmission electron microscopy. Prepubertal (0-4 weeks of development) and pubertal (4-8 weeks of development) males were examined. Effects of castration on the development of the fibrocartilage were also examined. During the first 0-4 weeks of development, cells in the primordium of the fibrocartilage became large and the cytoplasm had well-developed rough endoplasmic reticulum (rER) and many intermediate filaments. Collagen fibers increased markedly in amount in the extracellular matrix (ECM) during the period. For 4-6 weeks, when gonadal secretion of androgens increases, the cells developed into mature chondrocytes with lacunae. Collagenous bundles were pushed away from the lacunae, resulting in a characteristic appearance of this fibrocartilage. The cytoplasm of the mature chondrocytes of the fibrocartilage was characterized by many intermediate filaments, oil droplets, glycogen granules, and well-developed rER. At 6 weeks, calcification started on the cell membrane of the mature chondrocytes. At 8 weeks, a large part of the cartilage matrix was calcified. Matrix vesicles that originate from degenerated chondrocytes were found in the ECM of decalcified samples. In castrated males, cells of the primordium of the fibrocartilage ceased further development after castration. Intermediate filaments were still abundant in the cytoplasm and collagen fibers increased even after castration, but mature chondrocytes never differentiated. There were no signs of matrix vesicle formation, calcification, or cell degeneration in the fibrocartilage primordium. The developmental process of the fibrocartilage can be subdivided into two phases: collagenous matrix formation during the prepubertal period (0-4 weeks), and maturation of chondrocytes and calcification after puberty (4-8 weeks).