The role of cartilage canals in the ossification of the talus

Interrupted serial sections of the foot region from 14 human fetuses, crown-rump (CR) lengths between 32 and 240 mm, were studied, using HE, PAS, Alcian blue, Gomori's trichrome and von Kossa stains. Cartilage canals carrying vascular connective tissue from the perichondrium entered the talus by 68-mm. The centre of ossification developed in the neck region of the talus cartilage by 240 mm CR length, but early stages of chondrocyte proliferation and hypertrophy were noted by 108-mm CR length. The latter is marked by 170 mm CR length. A number of cartilage canals were observed around the developing centre. Branches from these cartilage canals appeared to supply vascular osteogenic tissue to its marrow spaces.

Activity of peroxidase and delta 5-3 beta-hydroxysteroid dehydrogenase in the ovary of LH-treated cyclic female rats

Rats were treated with LH at 08:00 h on the first day of dioestrus or on Days 1 and 2 of dioestrus. Peroxidase activity increased within 3 h in females injected with LH on Day 1 and was associated with a depletion of ascorbate that lasted until the afternoon of Day 1. Values of both substances then returned to basal values by the morning of Day 2. A second LH injection on Day 2 produced effects similar to those seen after LH on Day 1. Females treated with LH did not display greater delta 5-3 beta-HSD activity than did controls on Day 1 after one LH injection, but did on Day 2 after two LH injections. Nonetheless, the changes were only modest by comparison with those of peroxidase. The peroxidase-ascorbate system appears to be involved in the mechanism responsible for the increased secretion of ovarian progesterone resulting from LH stimulation.

Studies on peroxidase-catalyzed formation of progesterone

Subcellular fractions of pregnant rabbit ovary at day six of gestation catalysed the formation of progesterone from pregnenolone (3 beta-hydroxy-5-pregnen-20-one). The microsomal fraction was found to have maximum activity. The enzyme needed hydrogen peroxide for its activity. In vitro studies using horseradish peroxidase also showed similar conversion and this was stimulated 200% in the presence of ascorbic acid. Ascorbate thus appears to perform a catalytic role in this conversion. The importance of peroxidase in luteal steroidogenesis is indicated.

Localization of some steroidogenic enzymes in the ovary of the rabbit

The distribution of delta 5-3 beta-HSD, peroxidase and cytochrome oxidase in immature, sexually mature and pregnant rabbit ovary has been studied histochemically. Corpora lutea are found only in pregnant rabbits. delta 5-3 beta-HSD is present in the theca interna of mature follicles, corpora lutea and interstitial gland cells but is absent in the granulosa cells of both developing and mature follicles. The granulosa cells of mature and developing follicles, hypertrophied theca interna and the luteal cells all show intense cytochrome oxidase activity. Peroxidase is present in the corpora lutea only. It is suggested that delta 5-3 beta-HSD in the theca interna and interstitial gland cells is the enzyme responsible for steroid synthesis in the ovaries of immature as well as sexually mature rabbits, while peroxidase and delta 5-3 beta-HSD present in the corpora lutea together regulate luteal steroidogenesis during pregnancy. The intense cytochrome oxidase activity together with peroxidase and delta 5-3 beta-HSD confirms the observations that this tissue is a site of intense oxidative activity.

Ascorbate and peroxidase changes during pregnancy in albino rat and Swiss mouse

From the 1st to 6th days of pregnancy in the rat, while the blastocyst is still in the fallopian tube, there is high peroxidase activity in the corpus luteum, the blastocyst, and there is high peroxidase activity in the endometrium. On day 8 of pregnancy, peroxidase activity in the corpus luteum begins to fall rapidly, and there is a sharp rise in the peroxidase activity of the uterine endometrium. In all these tissues an inverse relationship exists between peroxidase and ascorbate content. We suggest the involvement of the peroxidase-ascorbate system in the mechanism of the extended function of the corpus luteum during pregnancy and a role for free radicals in the process of implantation of the blastocyst in the uterus.

Diazepam addiction: a case report

A case of addiction to Diazepam is reported. Severe withdrawal symptoms such as tremulousness, irritability, increased psychomotor activity, generalized muscle cramps, photophobia, retro-orbital pains and insomnia are described. Visual hallucinations, illusions, and paranoid features are also present in this case. Detoxification and management were accomplished by gradual withdrawal and the addition of another tranquilizer, anticonvulsant and muscle relaxant. The author reviews other such reports of abuse and addiction in the literature which call for wide recognition of the addictive properties of Diazepam and for restrictions on its indiscriminate prescription by physicians.

Histochemical studies on the peroxidase localization in the rat ovary and uterus during various reproductive stages

A histochemical study has been made of peroxidase changes in rat ovary and uterus during different developmental stages of the normal and pregnant rats. The peroxidase was found to be present in the corpus luteum of the ovary of both normal and pregnant rats as well as in the allantochorionic placenta, while the growing follicles in the immature and mature rat ovary showed no activity. The possible physiological significance of the peroxidase changes in relation to luteal steroidogenesis has been discussed.

Comparative histochemical study of the enzyme changes in the ovary and uterus of mammals with special references to steroidogenesis

A comparative study of the enzymes delta5-3beta-HSD, cytochrome oxidase and peroxidase has been made in the ovaries and uterus of mammals (mouse, guinea pig, cat and dog) during various reproductive phases. The granulosa cells of developing follicles, hypertrophied interstitial cells of thecal origin and the luteal cells show intense delta5-3beta-HSD and cytochrome oxidase activity. Peroxidases are found to be present in the corpus luteum and the epithelial cords of thecal origin. delta5-3beta-HSD and cytochrome oxidase activity is localized to the endometrium and myometrium of mature and pregnant uterus of mouse and guinea pig, while peroxidase is seen only in the decidua and endometrial glands of pregnant animals. The significance of these enzymes is discussed in relation to the cellular basis of luteinization and steroid hormone synthesis.

Induction of peroxidase in corpora lutea of rat ovary by lutropin

The lutropin-induced depletion of ascorbate in corpora lutea of albino-rat ovary is shown to be associated with the induction of peroxidase in corpora lutea. An inverse relationship between ascorbate depletion and peroxidase activity was established in a time-course study with lutropin. Analyses made at different phases of the reproductive cycle are in accord with this relationship. It is suggested that ascorbate, which is a well-established donor in peroxidase reactions, undergoes rapid oxidation in the presence of this enzyme, producing an intermediate free radical which, if coupled with pregnenolone, might produce progesterone in the corpora lutea. The exact role of peroxidase in steroidogenesis, however, remains to be elucidated and established.