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Biomedical subjects

D R Bennett

Publications and source records attributed to D R Bennett.

At least 37 records · Page 2Linked to original sources

Cranial CT appearance of acute multiple sclerosis.

In acute multiple sclerosis, cranial computerized tomography (CT) may show periventricular and deep white matter contrast-enhanced lesions that are easier to see using 8 mm rather than 13 mm cranial CT sections. Follow-up studies show that the lesions evolve either to areas of density similar to the surrounding white matter or to low-density lesions. We presume they represent foci of active demyelination with extravasation of iodine through an altered blood-brain barrier. Enhanced cranial CT studies may be helpful in diagnosing acute multiple sclerosis and in following the course of the white matter lesions.

Acute Disease↗

Studies on the effects of pharmacologic doses of cortisone acetate and several nonsteroidal anti-inflammatory compounds on ovo-implantation, early pregnancy, and the deciduomal response in the rat.

Cortisone acetate (10 mg/day), alone or in combination with progesterone (4 mg/day); progesterone (4 mg/day); progesterone (4 mg/day) plus estrone (1 microng/day); indomethacin (0.75 mg/day); phenylbutazone (20 mg/day); flufenamic acid (10 mg/day); and Compound 83161 (tetrazolo less than 1,5-alpha greater than s-triazolo less than 3,4-c greater than quinoxoline) (8 mg/day and 12 mg/day) were each given to intact rats during early pregnancy (days 1 and/or 2 through day 8). Only cortisone acetate treatment caused a true delay in ovo-implantation. Both progesterone treatment beginning on day 1 and cortisone acetate treatment beginning on day 1 or 2 caused an increased postimplantation fetal death rate. Compound 83161, at doses causing signs of general toxicity (12 mg/day), caused a marginal inhibition of implantation. Treatment with indomethacin, phenylbutazone, or flufenamic acid caused some inhibition of the traumatic deciduomal response in spayed rats treated with progesterone, while treatment with cortisone acetate and Compound 83161 did not.

Animals↗

Do aging changes in the preoptic area contribute to loss of cyclic endocrine function?

Two-year-old Wistar rats showing repeated periods of pseudopregnancy were compared with young rats that had electrolytic lesions placed in the medial preoptic area. Electrolytic lesions in the medial preoptic area in young rats induced repeated pseudopregnancies what were similar to those seen in the old pseudopregnant rats. Serum prolactin levels were elevated in both groups of rats. Administration of lergotrile mesylate (an ergot-dervied dopamine agonist and prolactin inhibitor) resulted in a reduction in serum prolactin levels and in the appearance of normal consecutive 4- or 5-day estrous cycles in the old rats and in the young rats with brain lesions. These results suggest that the repeated periods of pseudopregnancy in the aged rats may result from a deficiency in dopamine or from an abnormality in dopamine metabolism in neurons arising or passing through the medial preoptic area.

Aging↗

The effects of 5-bromo-2-thienyl-ethyl-ketone thiosenicarbazone on ovarian cyclicity and ovulation in the rat.

Pseudopregnant and cyclic rats were injected for 5 to 26 days with daily doses of 5 and/or 3 mg of 5-bromo-2-thienyl-ethyl-ketone thiosemicarbazone (70026) starting on Day 0 (the day of oestrus). The vaginal smear cytology, record of ovulation and ability to breed and conceive were compared with the results for corn oil-injected controls. Both doses of 70026 were found to cause a reappearance of pro-oestrous and/or oestrous vaginal smears within 4 to 6 days in the pseudopregnant rats, but ovulations did not occur. The 5-mg dose of 70026 inhibited ovulation and interrupted the oestrous cycle in cyclic rats, even though the daily 3-mg dose seemed to have little effect on ovulation, ovarian cyclicity, breeding or conception. In spite of the absence of an ovulation accompanying the induced pro-oestrous and/or oestrous vaginal smears in the pseudopregnant rats, the pattern of the vaginal smears suggested the occurrence of a 'delayed pseudopregnancy' in most of the pseudopregnant rats treated daily with 3 mg, but in few of those treated with 5 mg, 70026.

Animals↗