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Biomedical subjects

D R Pieper

Publications and source records attributed to D R Pieper.

At least 37 records · Page 2Linked to original sources
PubMed1993

Efficacy of cycled hyperinflation for rapid tissue expansion.

Temporary hyperexpansion at each filling session has previously been confirmed to increase the inflation volume in a conventional expansion procedure. This study employed eight young pigs to evaluate the effect of hyperinflation of this type in rapid expansion performed on 10 consecutive days. Hyperinflation to 120 mmHg for 4 minutes and deflation to 40 mmHg for 2 minutes was repeated five times on the experimental side. This cycled hyperinflation was found to increase the filling volume by 49 percent when compared with the contralateral side, which was not cycled or hyperinflated (control) (p < 0.01). The increase in surface area of the entire skin over the balloon was 178.1 percent in the hyperinflation group and 132.8 percent in the controls (p < 0.01). The actual expansion in surface area was not significantly different: 44.4 percent in the hyperinflation group and 45.7 percent in the control group. The additional gain of skin by cycled hyperinflation was the result of recruitment. The control group required 5 more days to achieve the same amount of skin but resulted in more true expansion and less recruitment. It is concluded that the cycled hyperinflation technique may shorten the time period of the whole reconstruction procedure but may produce an aesthetic deformity and flap necrosis.

Animals↗
PubMed1992

Unilateral but not bilateral olfactory bulbectomy inhibits body weight gain in hamsters.

The relation of the olfactory bulbs and photoperiod to the regulation of body weight was studied in male golden hamsters. Animals underwent sham operation, bilateral olfactory bulbectomy, or unilateral bulbectomy. They were left on long photoperiod for 5 weeks and then were transferred to short photoperiod for 11 weeks. The unilaterally olfactory bulbectomized hamsters gained less weight on long or short photoperiod than the sham operated group, while the bilaterally bulbectomized hamsters gained at least as much weight as the sham group. Thus, we report the novel finding that unilateral but not bilateral olfactory bulbectomy reduces body weight gain in male golden hamsters.

Animals↗
PubMed1991

Association of vascular compression in trigeminal neuralgia versus other "facial pain syndromes" by magnetic resonance imaging.

Magnetic resonance imaging was performed in 13 patients with trigeminal neuralgia and 18 control patients with facial pain of other types. Among trigeminal neuralgia patients, eight (62%) had vessels seen abutting, or immediately adjacent to, the trigeminal nerve on the side of their symptoms. Only three control patients (17%) had such vessels. The proportion of patients having a trigeminal region vessel associated with their symptoms was significantly higher in patients with trigeminal neuralgia than in controls (p = 0.0086). These findings provide evidence supporting the theory that trigeminal neuralgia is associated with vascular compression of the fifth cranial nerve.

Constriction, Pathologic↗
PubMed1991

Olfactory bulbectomy lengthens circadian period of locomotor activity in golden hamsters.

Removal of the olfactory bulbs (BX) of rats or mice lengthens the circadian period of locomotor activity. In golden hamsters, BX elevates serum gonadotropin levels of hamsters maintained in long or short photoperiod and prevents the testicular regression associated with short days without altering the secretion or action of pineal melatonin. The present study examined the influence of BX on circadian wheel-running activity in hamsters and tested whether this effect was related to changes in serum testosterone levels. BX lengthened the free-running period of locomotor activity in gonadally intact hamsters by a mean of 21.0 min, and BX had a similar effect in orchidectomized animals with or without testosterone replacement. These results suggest that the olfactory bulbs normally tend to increase the frequency of the hamster's circadian oscillator and that this effect is unrelated to altering gonadal steroid levels.

Animals↗
PubMed1990

Relation of hypesthesia to the outcome of glycerol rhizolysis for trigeminal neuralgia.

The effects of percutaneous retrogasserian glycerol rhizolysis were observed in a population of 58 cases of classical trigeminal neuralgia. The follow-up period ranged from 7 to 52 months postoperatively. It was noted that 84% of the patients had immediate relief of pain. The overall recurrence rate was 29%. Based on Kaplan-Meier survival curves, the overall half-life (T1/2) of this procedure was 16 months. Although none of the patients developed anesthesia dolorosa or corneal ulceration, one group of patients developed either a clinical or subclinical persistent "minimal hypesthesia." In these there was a statistically significant difference in the T1/2 associated with this procedure (p = 0.01). This finding suggests that, contrary to the general belief, persistent hypesthesia after glycerol rhizolysis is a negative indicator of long-term success.

Adult↗
PubMed1989

Bilateral transection of the lateral olfactory tract but not removal of the vomeronasal organs inhibits short-photoperiod-induced testicular regression in golden hamsters.

It is now known that removal of the olfactory bulbs increases basal gonadotropin secretion and prevents short-photoperiod-induced testicular regression in Syrian hamsters. The experiments described in the present paper were an attempt to determine which neuronal systems associated with the olfactory bulbs are responsible for this influence on the reproductive neuroendocrine axis. In the first experiment, removal of the vomeronasal organ failed to influence gonadotropin secretion or testes weight in hamsters on long or short photoperiod, suggesting that the vomeronasal-accessory olfactory pathway is not individually responsible for the effect of the olfactory bulbs on gonadotropin secretion. In the second experiment, bilateral transection of the lateral olfactory tracts (LOT) did prevent short-photoperiod-induced testicular regression and the associated decrease in gonadotropin secretion. Since the nervus terminalis is confined to the surface of the medical olfactory bulb pathway, the results of LOT transection indicate that the nervus terminalis, which itself contains gonadotropin releasing hormone, does not mediate the influence of the olfactory bulbs on gonadotropin secretion. These results further suggest that the olfactory bulb influence on gonadotropin secretion is due to neural connections to the pyriform cortex, entorhinal cortex or amygdala.

Animals↗
PubMed1989

Tissue ferritin concentration and prognosis in carcinoma of the breast.

Seven year follow-up data were available on 36 of 40 breast carcinoma patients in whom breast tissue ferritin concentrations at the time of surgery were known. 18 patients were alive and free of recurrence or second tumor (Group 1) and 11 died with breast cancer (Group 2). Patients with lower tissue ferritin concentrations defined as less than 319 ng/mcp (nanograms of ferritin/milligram of cytosol protein) were at reduced risk: 86% of patients with low tissue ferritin concentration survived free of recurrence or second tumor vs. 40% of patients with high tissue ferritin concentration (P = 0.0056). Mean breast carcinoma tissue ferritin concentration was 295 +/- 52 ng/mcp in Group 1 and 444 +/- 55 ng/mcp in Group 2 (P = 0.036). Lymph node involvement was predictive of mortality from breast carcinoma (P = 0.0003), but did not correlate with mean tissue ferritin concentration (P = 0.082). 10/10 (100%) patients who had both low tissue ferritin concentration and absence of lymph node involvement were in Group 1. The correlation of breast tissue ferritin concentration with histopathologic dedifferentiation and with prognosis suggests tumor tissue ferritin as a marker of malignant potential.

Breast Neoplasms↗
PubMed1988

Evidence that olfactory bulbectomy does not influence testicular regression in golden hamsters on short photoperiod by altering pineal melatonin production.

A recent study has shown that olfactory bulbectomy (BX) will prevent reproductive regression associated with short photoperiod in male golden hamsters. The results of experiments reported in this paper show that bulbectomized hamsters on long or short photoperiod still show a large nocturnal elevation in pineal melatonin production and that BX inhibits the reproductive regression induced by exogenous melatonin in pinealectomized hamsters. The data therefore indicate that BX does not inhibit short photoperiod induced testicular regression by altering melatonin secretion.

Animals↗
PubMed1988

Altered cerebral dominance in an atopic population.

Handedness was assessed in 853 subjects, 424 from an allergy office practice and 429 from a health screening clinic, using a modified Oldfield Handedness Inventory. Subjects also responded to a survey ascertaining both personal and family histories of allergy-related problems and left-handedness. A significant left-handed shift in mean laterality quotient and an increased incidence of left-handedness was found in participants from the allergy office and in subjects who considered themselves to be affected by allergy, allergic rhinitis, and/or asthma. Controlling for nonatopic responders from the allergy office and possibly atopic responders from the health screening clinic, mean laterality quotients were 66.4 +/- 51.6 vs 79.4 +/- 42.1 (p less than .001) and the incidence of left-handedness was 12.1% vs 6.8% (p less than .05). Mean laterality quotient of 125 asthmatics was 65.1 +/- 54.0, and 16 (12.8%) were left-handed. The mean percentage of left-handed children of 79 asthmatic parents was found to be increased: 16.7 +/- 26.3% vs 10.3 +/- 21.2% of children of 198 nonatopic parents (p less than .02). This was attributable to left-handed children of asthmatic women, 18.6 +/- 29.0% (p less than .01), but not asthmatic men. Both autonomic neurologic dysfunction and disordered immunoregulation typify atopic disease. Our results can be interpreted to reflect this duality and lend support to Geshwind's hypothesis of a relationship between cerebral dominance and immunologic set resulting from common developmental influences.

Adult↗
PubMed1988

Exercise inhibits reproductive quiescence induced by exogenous melatonin in hamsters.

Voluntary exercise inhibits the reproductive regression associated with a short photoperiod in male or female hamsters. The question addressed by the present study was whether exercise would also attenuate the reproductive regression associated with injection of exogenous melatonin. In male hamsters exercise inhibited the testicular regression, decline in gonadotropin secretion, and reduction in testosterone release associated with two daily injections (15 micrograms) of melatonin in pinealectomized hamsters on long days. After the reproductive system of the sedentary melatonin group had regressed, one-half of these hamsters were placed in cages with exercise wheels. Access to the exercise wheels stimulated testicular recrudescence and restored gonadotropin secretion to levels found in vehicle-injected hamsters. Sedentary female hamsters injected with melatonin tended to go into a state of constant diestrus associated with daily afternoon increases in serum luteinizing hormone, whereas most exercising hamsters injected with melatonin generally continued having regular estrous cycles with proestrus luteinizing-hormone surges. The ability of exercise to inhibit the effect of exogenous melatonin in pinealectomized hamsters suggests that exercise acts, at least in part, by mechanisms other than altering melatonin secretion.

Animals↗
PubMed1987

Olfactory bulbs influence testosterone feedback on gonadotropin secretion in male hamsters on long or short photoperiod.

Previous studies have shown that prepubertal olfactory bulbectomy will prevent the testicular regression associated with short photoperiod in golden hamsters. The gonadal regression which normally occurs in hamsters on short photoperiod is known to be due in part to an increased responsiveness of the reproductive neuroendocrine system to the negative feedback actions of testosterone on LH and FSH secretion. The present study tested whether the olfactory bulbs influence the feedback effects of testosterone on gonadotropin secretion. Twenty-four- to 26-day-old male golden hamsters were either olfactory-bulbectomized (BX) or sham-olfactory-bulbectomized. Eight weeks later, all hamsters were castrated, and one half of each group was placed in LD 10:14 (this was called week-8 of the study), while the other half was returned to long photoperiod (LD 14:10). Eight weeks following castration (week 0 of the study), all animals were implanted with silastic capsules containing 0, 4, 8 or 16 mm of testosterone. All hamsters were bled by cardiac puncture at -8, -4, 0, +2, +4, +6 and +8 weeks. The concentration of LH and FSH in these samples was then determined by RIA. BX completely prevented the negative feedback of testosterone on gonadotropin secretion in hamsters on either long or short photoperiod at all levels of testosterone tested in this study. In addition, there were seemingly steroid-independent effects of BX on gonadotropin levels in the castrated hamsters prior to testosterone replacement at weeks -4 and 0.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Olfactory bulbectomy prevents short photoperiod-induced anestrus in female golden hamsters.

When female golden hamsters are maintained on a photoperiod of less than 12.5 h of light per day, they go into a pineal gland-induced anestrus in 6-10 weeks. This acyclicity is similar in certain respects to the testicular regression which occurs in male golden hamsters maintained on a short photoperiod. A recent study has indicated that pre-pubertal olfactory bulbectomy (BX) will prevent the testicular regression in adult male hamsters exposed to a short photoperiod. The present study tested the effect of pre-pubertal or adult BX on the anestrus associated with maintenance of adult female golden hamsters on short photoperiod. In Expt. 1, hamsters were pre-pubertally sham BX (SH) or BX (23-25 days of age) and then maintained on LD 14:10 or LD 6:18 for 15 weeks. In Expt. 2, hamsters were SH or BX as adults (63-65 days of age) and maintained on LD 6:18 for 13 weeks. The estrous cycles of all animals were monitored on a daily basis. In Expt. 1, all animals on LD 14:10 had regular estrous cycles for the duration of the study. Sixty percent of the SH group on LD 6:18 became anestrous, whereas 87.5% of the BX group on LD 6:18 continued having regular cycles. In Expt. 2, 80% of the SH group became anestrous while 90% of the BX group continued having regular estrous cycles. The possible mechanisms whereby BX affects the cyclicity of female hamsters is discussed. The fact that BX resulted in increased morning gonadotropin levels and ovarian weight in animals on LD 14:10, as well as in the hamsters on short photoperiod, suggests that there is a relationship between the olfactory bulb and the reproductive system that is independent of the photoperiod, in addition to more dramatic effects of olfaction on reproduction in animals on a short photoperiod.

Anestrus↗
PubMed1986

Pituitary gonadotropin releasing hormone (GnRH) receptor levels in intact and ovariectomized-adrenalectomized female golden hamsters on a short photoperiod.

Both intact and ovariectomized + adrenalectomized hamsters on a short photoperiod, had a daily surge in plasma LH at approximately 16.00-18.00 h. The number of pituitary GnRH receptors was generally lower in ovariectomized + adrenalectomized hamsters than in intact animals, but both intact and ovariectomized + adrenalectomized hamsters had a decrease in the number of receptors just prior to the LH surge. These results show that gonadal steroids are not involved in regulating the pre-LH surge fall in the number of GnRH receptors.

Adrenalectomy↗
PubMed1986

Olfactory bulbectomy prevents anti-gonadal effect of exogenous melatonin in male hamsters.

When male Golden hamsters are maintained on short days (less than 12.5 h of light/day) the testes gradually regress. This testicular regression is due to an inhibitory effect of pineal gland melatonin on gonadotropin secretion. A previous report from the author's laboratory has indicated that olfactory bulbectomy (BX) will prevent the testicular regression associated with short photoperiod. The present study examined whether BX would also prevent the testicular regression associated with exogenous melatonin (MEL) injections. Male Golden hamsters were BX or sham (SH) BX at 23-28 days of age and were maintained on 14:10 light-dark cycle. Six weeks following surgery, one half of each surgical group began receiving injections of melatonin (15 micrograms sc), whereas the other half was injected with vehicle at 1600 daily. The testes size of the SH group injected with MEL progressively decreased, whereas the testes of all other groups remained large. These results indicate that BX prevents the testicular regression associated with short photoperiod by interfering with the antigonadotropic effect of melatonin.

Animals↗
PubMed1985

The influence of blinding, olfactory bulbectomy and pinealectomy on plasma and anterior pituitary prolactin levels and on uterine and anterior pituitary weights in normal and neonatally androgenized rats.

Lactating Sprague-Dawley rats had their litters adjusted to 8-10 pups on day 3 of lactation favoring females and some litters were injected with 1.25 mg of testosterone propionate to neonatally androgenize (NA) them. At 22-25 days of age both normal and NA animals were ovariectomized (OVX) and subjected to either sham olfactory bulbectomy (ANOS) + sham pinealectomy (PX), blinding (BLD) + ANOS or BLD + ANOS + pinealectomy (PX). At 13 weeks of age all animals were injected with 0.5 mg of polyestradiol phosphate. At 15 weeks of age the animals were fitted with atrial catheters and at 16 weeks of age blood samples (0.3 ml) were obtained every 3 hours over a 24 hour period. Uterine and anterior pituitary (AP) weights were recorded at sacrifice. Plasma and AP were assayed for prolactin (PRL) by RIA and AP were also assayed for PRL using the Nb2 lymphoma cell PRL bioassay. In both normal and NA animals, BLD + ANOS suppressed plasma PRL levels and PX partially prevented this response. Uterine weights were similar among groups while AP weights were significantly lower for sensory deprived animals. Anterior pituitaries extracted at pH 7.6 had a PRL concentration that was higher for the BLD + ANOS groups when estimated by either RIA or BA, a result that was not observed when the AP were extracted at pH 10.6. The amount of PRL extracted at pH 10.6 was twice that obtained at pH 7.6. Sensory deprived animals that were OVX prepubertally and administered estrogen as adults had a small but significant increase in mean plasma prolactin at 1700 hr. Both normal and NA animals responded in a similar manner to experimental manipulation.

Animals↗
PubMed1985

Blind, olfactory bulbectomized female rats do not have daily luteinizing hormone surges.

Previous studies from other laboratories have shown that female hamsters on short photoperiod become acyclic and have daily LH surges. These effects are eliminated if the animals are pinealectomized (PX) before being placed on the short photoperiod. Reiter and colleagues have shown that pre-pubertally blinded (BL) and olfactory bulbectomized (BX) female rats also have irregular estrous cycles, and this effect is also eliminated by PX [Endocr. Rev., 1 (1983) 109]. The main question addressed by the present study was whether the BL + BX rats also have daily LH surges. Twenty-five-day-old female Sprague-Dawley rats were divided into 5 groups: LD 14:10 sham (control); BL + BX; BL + BX + PX; LD 6:18 sham; and LD 6:18 BX. Ten weeks following surgery, all animals were sampled (0.5 ml) every 5 h for 2 days from an indwelling atrial catheter. Daily vaginal smears indicated that the BL + BX group were in estrus much less frequently than controls (15.8 +/- 1.8 vs 27.3 +/- 1.5% of days cornified cells, 10 rats/group smeared for more than 23 days each) and in general had longer, irregular cycles. The other 3 groups all had smear patterns similar to controls. All 5 groups had LH surges on the day of proestrus (greater than 200 ng/ml maximum value), but no group had LH surges on 2 sequential days or an LH surge on any other day of the cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Olfactory bulbectomy prevents the gonadal regression associated with short photoperiod in male golden hamsters.

In male rats, pre-pubertal olfactory bulbectomy (BX) unmasks photoperiodic responsiveness so that maintenance of BX animals on short photoperiod results in a pineal gland mediated gonadal regression (Nelson and Zucker, Neuroendocrinology, 32 (1981) 266). The objective of the present study was to determine the effect of BX in Syrian hamsters, a species where short photoperiod alone induces a pineal gland induced testicular regression. Pre-pubertal (25-days old) Syrian hamsters underwent either sham BX, BX, or pinealectomy (PX) plus BX. One half of each group was then placed on an LD 14:10 photoperiod and the other half on LD 6:18. Thirteen weeks later all animals were decapitated. In the animals on LD 14:10, BX resulted in a slight but highly significant increase in testes weight but had no effect on other parameters examined. Sham BX hamsters on LD 6:18 had regressed testes and reduced serum testosterone levels, but these effects of short photoperiod were reversed in BX hamsters, so that the testes and seminal vesicles remained large. In addition, serum LH and testosterone levels were elevated following BX of the animals on LD 6:18. These results indicate that the olfactory bulbs tonically inhibit the reproductive system even in male hamsters maintained on long photoperiod and that olfactory bulbectomy prevents gonadal regression in male Syrian hamsters on short photoperiod, an effect which is the opposite of results obtained in rats on short photoperiod. Elucidation of the neural pathways involved and the nature of the relationship between the olfactory bulb and the pineal gland or photoperiodism remains for further investigation.

Animals↗