PubMed Health⌕ Search

Biomedical subjects

L D Anderson

Publications and source records attributed to L D Anderson.

13 recordsLinked to original sources
PubMed1979

Effects of follicular development on the ability of cultured porcine granulosa cells to convert androgens to estrogens.

Porcine granulosa cells from different stages of follicular development were examined for their ability to convert androgens to estrogens and their ability to secrete progesterone. Granulosa cells from all stages of follicular development can convert androgens to estrogens, and the addition of exogenous androgen is required for estrogen secretion. Granulosa cells obtained from medium and large follicles have a greater capacity to convert androgens to estrogens than do granulosa cells obtained from small follicles. The addition of FSH brought about an increase in estrogen secretion in the presence of androgen only in granulosa cells from large follicles. LH attenuated estrogen secretion in granulosa cells from medium follicles treated with testosterone. Granulosa cells from medium follicles were unable to secrete estrogen from days two to four irrespective of treatment. Androgens augment FSH stimulated progesterone secretion in granulosa cells from medium follicles from days two to four, and the addition of follicular fluid from small follicles stimulates progesterone secretion in the presence of FSH and androgens.

Androgens↗
PubMed1979

Inhibitory effect of charcoal-treated porcine follicular fluid upon serum FSH levels and follicular development in the rhesus monkey.

Injection of charcoal treated porcine follicular fluid into 4 intact, 4 long term castrate and 2 postmenopausal rhesus monkeys brought about a selective decline in serum FSH levels. Luteinizing hormone levels were not significantly decreased. Intraperitoneal injection of 4 ml porcine follicular fluid every 8 hours for the first 4 days of the menstrual cycle led to a decrease in follicle and granulosa cell growth observed at that midcycle. Treatment with porcine serum did not exert this effect.

Animals↗
PubMed1979

Evidence that the pituitary gland is the site of inhibitory action of porcine follicular fluid upon FSH secretion in the rat.

This study has examined the effects of porcine follicular fluid (PFF) on the adenohypophyseal secretion of LH and FSH following LHRH treatment. The animal model selected for study the the proestrous rat in which preovulatory LH and FSH surges were blocked with phenobarbital. To elicit the release of gonadotropins from this preparation, two different i.v. LHRH infusion protocols were used. The first elicited a proestrous-like LH and FSH surge while the second infusion schedule evoked the predominant release of FSH with only minor changes in LH. PFF suppressed LHRH-induced FSH secretion in both preparations but had only negligible effects on LH secretion. Interestingly, the suppressive effects of PFF were variable and depended upon the mode in which LHRH was presented.

Animals↗
PubMed1979

Orthodontic attitudes toward national health insurance.

Data were obtained by surveying North Carolina orthodontists by means of a mailed questionnaire. Their responses were coded to make possible analysis by computer and were compared to responses from a national sample of dentists in the 1975 Survey of Dentists. Both North Carolina orthodontists and dentists nationwide agreed that some form of dental care should be provided if a national health insurance system were established. Compared to the dentists surveyed nationwide, the orthodontists favored a wider range of coverages but advocated providing a narrower scope of dental services. They indicated more strongly their general belief that a government health program would lead to regulation outside the private sector. The orthodontists disagreed more strongly with the claim that government health programs could provide more people with high-quality dental care. Both groups anticipated that comprehensive dental care in a national health insurance system would result in fixed fees set by the government. Only 62 percent of the orthodontists polled were familiar with HMOs. Of this group, nearly 90 percent chose not to contract with these organizations.

Attitude↗
PubMed1979

Suppression of pituitary secretion of follicle-stimulating hormone by porcine follicular fluid during pro-oestrus and oestrus in the rat: effects on gonadotrophin and steroid secretion, follicular development and ovulation during the following cycle.

In this study, we have examined whether the suppression of raised plasma FSH concentrations at pro-oestrus and/or oestrus by porcine follicular fluid (PFF) affected the development of follicles for ovulation in the next cycle. Adult, 4-day-cyclic rats were injected with PFF or pig serum at various hours of pro-oestrus and oestrus. Plasma FSH levels were suppressed following PFF treatment at any time of pro-oestrus and oestrus. Furthermore, this suppression was always followed by a 'rebound' increase in plasma FSH. In contrast, plasma LH concentrations were unaffected by PFF treatment and neither gonadotrophin was altered by treatment with pig serum. When rats treated with PFF or pig serum were allowed to complete one additional cycle, plasma LH and FSH concentrations at the pro-oestrus and oestrus after treatment were not significantly different among groups regardless of treatment or time of treatment. All ovaries of rats treated with PFF or pig serum on the next pro-oestrus morning before ovulation were histologically similar. Furthermore, all animals ovulated a normal complement of ova at the next oestrus regardless of whether preovulatory, secondary or both increases of plasma FSH had been blocked by PFF treatment during the previous cycle. However, animals given PFF during the preceding cycle, plasma oestradiol and progesterone concentrations were significantly altered on the morning and afternoon of pro-oestrus respectively. These results suggest that increased plasma FSH concentrations at pro-oestrus and oestrus may not be essential for folliculogenesis and ovulation in the subsequent cycle. Alternatively, the 'rebound' of FSH on day 1 of dioestrus after the suppression of both phases of FSH secretion at pro-oestrus and oestrus may be sufficient to provide ovulatory follicles for the next pro-oestrous day.

Animals↗
PubMed1977

Hormonal regulation of the number and activity of ribosomes in mammary gland explants of mice.

Possible effects of insulin, hydrocortisone and prolactin on the number and activity of ribosomes enganged in protein biosynthesis in mammary gland explants were explored. The rate and extent of [3H]-puromycin attachment to nascent peptides was used to assess, respectively, the activity and number of ribosomes engaged in protein biosynthesis. None of the hormones altered the number of ribosomes engaged in protein biosynthesis. In addition, of the hormones tested, only insulin appeared to accelerate the rate at which ribosomes carried out the translocation process. The early (1 hr) effect of insulin on protein biosynthesis in the mammary gland would therefore appear to occur via an activation of ribosomal activity. In contrast, the early (6 hr.) effect of prolactin on protein biosynthesis would appear to be exclusively via an RNA-DNA dependent mechanism.

Animals↗
PubMed1976

Phospholipases and the effect of prolactin on uridine incorporation into RNA in mammary gland explants of mice.

The possible effects of phospholipase A and phospholipase C on the rate of uridine incorporation into RNA in mammary gland explants of mice were tested. Phospholipase C had no effect on the rate of uridine incorporation, but it did suppress the action of prolactin on this metabolic parameter. In contrast, phospholipase A was found to stimulate the rate of uridine incorporation into RNA in a manner similar to that of prolactin. The time-courses for the onset of the prolactin and phospholipase A effects were the same. Also, the phospholipase A effect was nonadditive to the effect produced by a maximally stimulatory concentration of prolactin. Finally it was observed that, like the prolactin effect, the phospholipase A effect was abolished by incubation with dibutyryl cyclic AMP, theophylline, quinine, indomethacin and prostaglandin E1. Further, the phospholipase A effect was nonadditive to the prolactin-like effects produced by the cyclic GMP, prostaglandin F2alpha or arachidonic acid. These data therefore suggest that prolactin and phospholipase A stimulate RNA synthesis in mammary gland explants via similar processes.

Animals↗
PubMed1976

Rapid interaction of prolactin with mouse mammary gland explants.

Exposure of mouse mammary gland explants to prolactin at 0 degrees C, for periods as brief as 10 seconds, caused a stimulation of labeled uridine incorporation into RNA during a subsequent incubation for 4 h at 37 degrees C. Furthermore, a 2-h wash of the prolactin-exposed explants in media at 0 degrees C did not attenuate the hormonal effect. A similar exposure of explants to insulin, followed by a 2-h wash at 0 degrees C, caused the abolition of the insulin stimulation of labeled uridine incorporation into RNA. The results suggest that there is a rapid and relatively stable interaction of prolactin with the mammary gland, while the interaction of insulin with this tissue would appear to be less stable.

Animals↗
PubMedDate not supplied

Injuries of the forefoot.

Dislocations and fracture-dislocations of the tarsometatarsal joints, fractures of the base of the fifth metatarsal bone, fractures of the shafts and necks of the metatarsal bones, dislocations of the metatarsophalangeal joints, fractures of the phalanges and dislocations of the interphalangeal joints each have a specific mechanism of injury, characteristic diagnostic feature, and requirement for treatment. Only by an accurate diagnosis established by careful physical and roentgenographic examination can complications be avoided.

Accidents, Home↗