PubMed Health⌕ Search

Biomedical subjects

D R Pieper

Publications and source records attributed to D R Pieper.

At least 19 recordsLinked to original sources
PubMed2000

Characterization of serum dehydroepiandrosterone secretion in golden hamsters.

Dehydroepiandrosterone (DHEA) is an adrenal androgen whose function is poorly understood. Although DHEA and DHEA sulfate (DHEAS) are secreted in relatively high quantities by the human adrenal, the laboratory rat secretes very little, thus hindering experimental studies of the hormone. In this paper, we measured the changes in serum DHEA and DHEAS under various physiological conditions in golden hamsters. Evening serum DHEAS fell from 6.30 +/- 0.78 microg/dl (mean +/- SE) before surgery to 3.03 +/- 0.23 microg/dl 12 days after bilateral adrenalectomy. Hamsters had higher levels of DHEA and DHEAS in the evening than in the morning, but removal of the gonads did not consistently decrease serum DHEA or DHEAS in males or females. Evening levels of DHEA and DHEAS reached a peak around 7 weeks of age and then gradually decreased to about one-third of these levels by one year of age. These results suggest that DHEA and DHEAS are secreted at least in part from the hamster adrenal, that they do not originate from the gonads, and that there is a daily rhythm with peak levels at a time of day just preceding the active phase. In addition, the levels of these hormones decrease with aging.

Adrenal Glands↗
PubMed2000

Percutaneous retrogasserian glycerol rhizolysis for treatment of chronic intractable cluster headaches: long-term results.

OBJECTIVE: To analyze the long-term effectiveness and safety of percutaneous retrogasserian glycerol rhizolysis (PRGR) in the treatment of medically refractive chronic cluster headache (CH). The current mainstay of surgical intervention for these patients is percutaneous radiofrequency retrogasserian rhizotomy (PRFR). However, when performed for V1 distribution pathology, PRFR can lead to corneal anesthesia, which places the patient at risk for future visual loss. It also increases the risk of facial dysesthesia. METHODS: In a prospective, consecutive series, 18 patients with intractable CH were followed for a mean of 5.2 years (range, 40-78 mo) after they had undergone PRGR, performed using a standard technique. The significance of this technique as an alternative to PRFR is that it should result in a lower rate of both corneal and facial anesthesia and provide an acceptable degree of pain relief. RESULTS: Fifteen patients (83%) obtained immediate pain relief after one or two injections; the majority of them experienced relief after the first injection. CH recurred in seven patients (39%) over the course of the study. Two of these patients received a second injection, and both met with equal success. Two other patients underwent PRFR. Excluding those who underwent PRFR, the overall daily headache frequency decreased from 3.5 +/- 0.3 attacks per day preoperatively to 0.6 +/- 0.2 attacks per day at last follow-up. The severity of these headaches, as assessed by verbal pain scales, also decreased from 10 preoperatively to 4.4 +/- 1.4 at follow-up. None of the patients, including those who required a second procedure, experienced corneal anesthesia or facial dysesthesia. CONCLUSION: This study provides the first long-term evaluation of PRGR for the treatment of medically refractive chronic CH and lends support to both the safety and long-term efficacy of this procedure. Further investigations are needed to compare directly the relative efficacy and safety of PRGR and PRFR.

Adult↗
PubMed2000

Pituitary carcinoma containing gonadotropins: treatment by radical excision and cytotoxic chemotherapy: case report.

OBJECTIVE AND IMPORTANCE: Pituitary carcinomas are extremely rare. Cases reported in the medical literature in the 20th century included tumors that produced adrenocorticotropic hormone, prolactin, growth hormone, and/or thyrotropin. CLINICAL PRESENTATION: Here we present a 22-year-old woman with a pituitary carcinoma that was immunohistochemically positive for luteinizing hormone and follicle-stimulating hormone at both the primary and metastatic sites. The patient exhibited elevated serum levels of alpha-subunit. INTERVENTION: The patient had experienced failure of previous treatments, including standard surgery and radiotherapy, and presented to us for radical resection of the tumor, with exenteration of the involved cavernous sinus. She was pretreated with cytotoxic chemotherapy and continued to receive this therapy after surgery. CONCLUSION: This is the only documented case of a gonadotropin-staining pituitary carcinoma for which hormone production was proven in both the primary and metastatic tumors. Many benign "nonsecreting" pituitary adenomas actually produce subclinical amounts of gonadotropins, and malignant nonfunctional pituitary neoplasms may do the same.

Adult↗
PubMed1999

Dehydroepiandrosterone and exercise in golden hamsters.

Dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) are adrenal androgens that have been associated with a sense of well-being in humans. We describe two experiments done to test the hypothesis that an increase in DHEA or DHEAS secretion is associated with the inclination to exercise using a hamster model. In the first experiment, morning blood samples were obtained from adult male golden hamsters at various intervals after being placed in cages with (EX group) or without (SED group) access to running wheels. The EX group had lower DHEA (6, 12, and 14 weeks; p < 0.05) and DHEAS (13 and 16 weeks; p < 0.01) levels than the SED hamsters. In the second experiment, the number of wheel revolutions was monitored in castrated adult male hamsters implanted with Silastic capsules containing no hormone (blank control group), testosterone, or DHEA. The number of wheel revolutions in the group receiving DHEA was not significantly different than the blank control group, whereas testosterone increased wheel running at 4, 5, and 7 weeks (p < 0.05). These results indicate that DHEA and DHEAS levels decrease with exercise in male golden hamsters and that exogenous DHEA does not enhance the tendency to run on wheels.

Animals↗
PubMed1999

Neural pathway from the olfactory bulbs regulating tonic gonadotropin secretion.

Removal of the olfactory bulbs of male golden hamsters results in a marked increase in tonic gonadotropin, prolactin and testosterone secretion which counteracts inhibitory effects of manipulations such as maintenance on short photoperiod, food restriction or treatment with gonadal steroids. The bulbectomy-induced increase in hormone secretion is interpreted to reflect a tonic inhibitory influence of the olfactory bulbs. This inhibition is not dependent upon chemosensory stimulation and may be mediated by olfactory bulb fibers projecting through the lateral olfactory tract to or through the olfactory tubercle. This review will relate these studies conducted on hamsters to results in other species, such as the rat, where the olfactory bulbs enhance serum gonadotropin levels.

Animals↗
PubMed1999

Hyperostosis associated with meningioma of the cranial base: secondary changes or tumor invasion.

OBJECTIVE: Hyperostosis associated with intracranial meningiomas is a well-described entity. The cause, management, and prognosis of these bony changes have long been a point of controversy. Some authors have postulated that hyperostotic changes are secondary to the formation of the tumor and do not constitute invasion of the tumor into the bone. Determining this point has direct implications in the treatment of these patients, especially regarding surgical considerations. To more thoroughly evaluate this question, a study correlating the morphology to the radiology is necessary. METHODS: In this study, 51 patients underwent resection for meningiomas involving the cranial base. Preoperative radiographic evaluation using magnetic resonance imaging and/or computed tomography was performed, and areas of hyperostosis were identified. During the resection of the tumor, biopsies from these hyperostotic regions were sent for histological evaluation regarding the presence or absence of tumor invasion of the bone. RESULTS: Preoperative neuroradiological assessment identified 26 patients with radiographic evidence of hyperostosis. Histological examination of the resected bone showed tumor invasion in 35 patients, including the area of radiographically identified hyperostosis in 25 of the 26 patients. The floor of the middle fossa was a specific area of low sensitivity for preoperative assessment of associated hyperostosis. CONCLUSION: These results indicate that hyperostosis associated with meningiomas involving the cranial base are caused by tumor invasion of the bone histologically.

Adult↗
PubMed1999

Management of intracranial meningiomas secondarily involving the infratemporal fossa: radiographic characteristics, pattern of tumor invasion, and surgical implications.

OBJECTIVE: Intracranial meningiomas extending into the infratemporal fossa (ITF) are uncommon. This series describes the radiographic characteristics, histological pattern of invasion, and implications for surgical treatment of intracranial meningiomas. METHODS: Nine patients (median age, 52 yr) underwent resection of a transcranial meningioma extending into the ITF. Five patients (56%) had undergone a previous resection; however, none had involvement of the ITF. Four patients (44%) had received prior radiation therapy to the area. RESULTS: Preoperative neuroradiography uniformly showed erosion of the middle fossa floor and extension of the tumor through cranial base foramina. Histological results indicated tumor invasion of the middle fossa floor and skeletal muscle in all patients. Perineural invasion was present in four patients. Mucosal invasion was observed in six patients. A middle fossa/zygomatic approach provided access to the intra- and extracranial components of the tumor, as well as the cavernous sinus, ITF structures, paranasal sinuses, and nasopharynx. Reconstruction was performed using the temporalis muscle, which provides a vascularized flap between exposed mucosa and the carotid artery and intradural structures. A gross total resection was performed in seven patients (78%). Postoperative complications included soft tissue ischemia (one patient), worsening of preoperative cranial neuropathy (two patients), and lower extremity deep vein thrombosis (two patients). One patient died 2 months postoperatively from a pulmonary embolus. Two patients had recurrence of intracranial meningiomas extending into the ITF at 2 and 3 years postoperatively, necessitating further resection. CONCLUSION: Understanding the pertinent clinical and morphological aspects of meningioma transcranially involving the ITF is essential to surgical treatment of patients with this condition.

Adult↗
PubMed1998

Removal of the olfactory bulbs delays photic reentrainment of circadian activity rhythms and modifies the reproductive axis in male Octodon degus.

The diurnal rodent, Octodon degus, exhibits robust sex differences in several circadian measures, including circadian period (tau) and reentrainment rates to photic and nonphotic (social) zeitgebers. The neural substrates underlying such physiological differences remain unknown. In female degus, olfactory bulbectomies (BX) inhibit socially-facilitated reentrainment, but do not alter photic reentrainment, entrained measures, or tau in constant darkness (DD). This experiment investigated the effects of BX in male degus on (i) photic reentrainment rates of circadian rhythms following a 6-h phase advance of the light-dark (LD) cycle; (ii) photic entrainment; (iii) tau of free-running activity rhythms in DD; and (iv) body weight, paired testis weight, and the reproductive hormones, testosterone, androstenedione and follicle stimulating hormone (FSH). BX significantly delayed photic reentrainment rates. They did not, however, modify tau, the phase of activity onset or offset, amplitude or duration (alpha) of the activity rhythm, mean daily locomotor activity levels, or body weight. FSH, testosterone and androstenedione were unaffected by BX, whereas paired testis weights were significantly greater in BX degus compared with shams. Thus, the olfactory bulbs influence photic reentrainment of circadian rhythms and modestly affect the reproductive axis in male degus. Our results suggest that the olfactory bulbs may be a neural source of observed sex differences in photic reentrainment in degus, and highlight interspecies variation in the olfactory bulbs' effects on entrained and free-running circadian rhythms and on reproduction.

Animals↗
PubMed1997

Role of surgery in the treatment of brain metastases in patients with breast cancer.

BACKGROUND: Patients whose brain metastases from breast cancer are treated nonsurgically have a median length of survival ranging from 2.5 to 7.5 months, and a median time to recurrence ranging from 2 to 5 months. Patients treated with radiotherapy have a median length of survival ranging from 3 to 4 months. Those treated with chemotherapy have a median length of survival ranging from 5.5 to 7.5 months. METHODS: We conducted a retrospective analysis on 63 patients treated over a 10-year period. Only patients who underwent surgery for nonrecurrent brain metastases were studied. Sixty-one patients (97%) underwent surgery within 2 weeks of diagnosis of the brain metastases. RESULTS: The median length of survival was 16 months (95% confidence interval [CI] 11 to 22 months), and the 5-year survival rate was 17% (CI 9% to 29%). Brain metastases recurred in 27 patients at a median interval of 15 months (CI 12 to 24 months). Eleven patients had local recurrence, 10 had distal recurrence, and seven developed leptomeningeal disease. Significant prognosticators of length of survival were age (p = 0.011), menopause status (p = 0.10), postoperative radiotherapy (p = 0.054), preoperative neurologic status (p = 0.011), and preoperative systemic disease status (p = 0.0003). Systemic disease status had a significant effect on the length of survival but not on the time to recurrence.

Adenocarcinoma↗
PubMed1997

Bromodeoxyuridine improves the cytotoxic effect of cisplatin: a comparison with 5-fluorouracil.

We compared the effects of the radiosensitizers, 5-bromo-2'-deoxyuridine (BUdR) and 5-fluorouracil (5-FU) alone and in combination and cis-diamminedichloroplatinum (cisplatin, DDP) on the growth of B16 amelanotic melanoma (B16a) tumors in mice. In a preliminary study, tumor growth was significantly inhibited in the presence of BUdR and was further reduced with the combination of BudR and DDP. In a second experiment, BUdR was found to be more effective than 5-FU when used in combination with DDP. At the completion of the study, tumor volumes as a percentage of control values in mice treated with a single drug were as follows: 5-FU (50 mg/kg per day for 7 days) 76.5% (P < 0.05), BUdR (100 mg/kg per day for 7 days) 68% (P < 0.05) and DDP (5 mg/kg x 3) 54% (P < 0.01). Combining 5-FU and DDP at these dosages reduced volumes to 38% (P < 0.01), while BUdR + DDP-treated mice had tumor volumes only 28% (P < 0.001) the size of untreated controls. Furthermore, the toxicity, as demonstrated by a decrease in body weight and an increase in mortality, was more severe in mice receiving 5-FU than in those receiving in BUdR. DDP interacts synergistically with either BUdR or 5-FU in its cytotoxic action in vivo. No such relationship could be demonstrated in vitro, suggesting that the pharmacologic activity of these drugs may be responsible for the antitumor activity than direct cytotoxic effects. We propose that BUdR is more effective than 5-FU as a potentiator of DDP in this murine melanoma model.

Animals↗
PubMed1996

Lesions of the ventral striatum mimic the effect of olfactory bulbectomy to prevent short photoperiod-induced testicular regression in golden hamsters.

Bilateral olfactory bulbectomy (BX) or bilateral transection of the rostral lateral olfactory tract (LOT) at the level of the anterior olfactory nucleus markedly increases gonadotropin secretion and prevents the testicular regression associated with maintenance on short photoperiod in golden hamsters. In an effort to further elucidate the neural tracts involved in this influence on gonadotropin secretion, lesions were placed in several potential pathways. Hamsters underwent sham surgery (SH), bilateral BX, or electrolytic or radiofrequency lesions of the: medial nucleus of the amygdala (MeX) caudal LOT just rostral to the medial nucleus of the amygdala (LOTX); or ventral striatum (VSX). Lesions were either bilateral or unilateral with contralateral olfactory bulbectomy. All animals were then placed on short photoperiod (LD 10:14) for 10 weeks and testicular size and body weight were assessed at weekly intervals. Lesion placement was assessed in brain sections stained with cresyl violet and animals with misplaced lesions were excluded. The following represent the number of animals in each group undergoing testicular regression in response to short photoperiod: SH: 32/35; BX: 8/31 (P < 0.01 vs. SH); MeX: 5/5; caudal LOTX: 8/9 and VSX: 3/8 (P < 0.05 vs. SH). Serum LH, FSH and testosterone at the end of the study correlated with the testicular regression data. These results suggest that the tonic inhibitory effect of the olfactory bulbs on gonadotropin secretion is mediated by fibers that exit the LOT rostral to the amygdala and project medially, either passing through or synapsing in the ventral striatum.

Amygdala↗
PubMed1996

Surgical management of patients with severe head injuries.

Minutes can make the difference between life and death when patients with severe head injuries require surgery. Subdural, epidural, and intracerebral hematomas and cerebral contusions and gunshot wounds are the pathologic entities encountered most frequently during emergency surgery in patients with severe head injuries. Neurosurgical team members frequently use hyperventilation, mannitol and barbiturates, and sophisticated monitoring modalities to manage patients with severe head injuries during and after surgery. Although monitoring a patient's intracranial pressure (ICP) through a ventriculostomy catheter remains the most widely used gauge of cerebral metabolism, neurosurgical teams also are using fiber-optic ICP monitoring catheters, cerebral blood flow measurement probes, microdialysis catheters, jugular venous oxygen saturation catheters, and brain oxygen content measurement electrodes. Coordinated teamwork by perioperative nurses, neurosurgeons, anesthesia care providers, and emergency department staff members helps ensure the best possible outcomes for patients who require surgery for management of severe head injuries.

Cerebral Hemorrhage↗
PubMed1996

Decreased adrenal sex steroid levels in the absence of glucocorticoid suppression in postmenopausal asthmatic women.

BACKGROUND AND AIM: Reduction of serum sex steroid levels has been reported to occur after the administration of beta-adrenergic medication. In that beta-adrenergic blockade is a central pathophysiologic feature of asthma, this study was done to explore the possibility of hormonal alteration in asthma. METHODS: Sex steroids obtained from 22 postmenopausal asthmatic and 22 age-matched, postmenopausal, nonasthmatic women were assayed. No subject had received estrogens, progestins, or oral corticosteroids for 120 days before the study. RESULTS: Mean dehydroepiandrosterone sulfate (DHEAS; p < 0.002), dehydroepiandrosterone (DHEA; p < 0.03), estradiol (p < 0.02), and estrone (p < 0.02) levels were lower in asthmatic patients compared with nonasthmatic subjects. Results could not be accounted for by current medication. Patients with asthma demonstrated no decrease in 17-hydroxyprogesterone or cortisol compared with nonasthmatic subjects, limiting findings to the delta 5, and not the delta 4, steroidogenic pathway. In a second phase of the study, DHEAS was measured before and after 3 days of oral beta-agonist stimulation in eight postmenopausal asthmatic women. Serum DHEAS concentration increased in eight of eight subjects, from a mean of 28.6 +/- 19.9 micrograms/dl (mean +/- SD) to 40.7 +/- 24.8 micrograms/dl (p = 0.002). Serum cortisol concentration was unchanged. CONCLUSION: The results indicate that postmenopausal asthmatic women have lower serum levels of adrenally derived sex steroids than their nonasthmatic peers and that this anomaly may be ameliorated by adrenergic stimulation.

Adrenergic beta-Agonists↗
PubMed1995

Voluntary exercise increases gonadotropin secretion in male Golden hamsters.

To determine the effect of voluntary exercise and food restriction on reproductive hormone secretion, 48 adult male hamsters were placed in cages with (EX) or without (SED) running wheels. One-half of the animals in each exercise group was fed ad libitum, and the other half was food restricted to reduce their body weight to 90 g over 4 wk. After 10 wk, the EX ad libitum-fed group had much larger testes and much higher serum follicle-stimulating hormone and testosterone levels than the other three groups, but these values in the EX food-restricted hamsters were similar to those in the SED food-restricted group. In experiment 2, 20 adult male hamsters were castrated and later implanted with silicone rubber capsules containing testosterone. Two weeks after implantation of the capsules, the serum follicle-stimulating hormone levels were higher in the EX than in the SED group of testosterone-treated hamsters, but not in animals receiving blank capsules. These data suggest that exercise increases gonadotropin secretion by inhibiting the negative feedback of testosterone.

Animals↗
PubMed1994

Laparoscopically assisted vaginal hysterectomy appears to be an alternative to total abdominal hysterectomy.

Seventy percent of hysterectomies in the United States are performed as total abdominal hysterectomies (TAH). Laparoscopic assisted vaginal hysterectomy (LAVH) has been promoted by some to be a low morbidity substitute for TAH. In this study, we compared the outcomes of 61 recent LAVH cases to 65 TAH cases performed during an earlier time interval. Data were abstracted from the charts of 65 TAH cases performed between August 1988 and December 1990 and 61 LAVH cases performed between June 1991 and September 1992 by the same gynecologist (E.D.R.). Patient characteristics and perioperative morbidities were compared. Patient characteristics were similar between the two groups except that LAVH procedures were performed on thinner women (148 +/- 3.4 vs 162 +/- 4.3 lbs, p < or = 0.01, LAVH vs TAH) and operating time was longer (137 +/- 4.1 vs 66 +/- 1.7 min, p < or = 0.0001). Uterine weights were comparable (152 +/- 12 vs 194 +/- 31 g, p = 0.2). There was less intraoperative blood loss (337 +/- 21 vs 417 +/- 16 ml, p < or = 0.003), febrile morbidity (9.8 vs 66%, p < or = 0.0001), respiratory complications (6.6 vs 22%, p < or = 0.05), and urinary morbidity (6.6 vs 24.4%, p < or = 0.02) and shorter postoperative hospitalization (22 +/- 1.2 vs 99 +/- 2.3 h, p < or = 0.0001) in the LAVH group. Thinner patients were selected for the LAVH procedure, and operating room time was twice that of those undergoing TAH. Conversely, perioperative morbidity and postoperative hospitalization time were significantly less with LAVH. LAVH appears to be an alternative to TAH.

Adult↗
PubMed1994

Olfactory bulbectomy counteracts inhibitory effect of food restriction on reproductive function.

Previous studies have shown that bilateral removal of the olfactory bulbs (BX) results in a large increase in gonadotropin secretion in golden hamsters. The principal question addressed by the present study was whether BX would offset the inhibitory effect of food restriction on reproductive function. BX or sham (SH) BX male golden hamsters were fed ad libitum or were restricted to only enough food to maintain them at 70% of the body weight of control groups fed ad libitum. The SH-70% group underwent marked testicular regression after approximately 6-8 wk, but the testes size of the BX-70% hamsters decreased only in proportion to the decrease in body weight. The BX food-restricted group had to be fed more food to maintain the same weight as the SH-70% hamsters, and the BX-70% group also had a higher core body temperature, lower percent body fat, and higher serum free thyroxine levels than SH food-restricted animals. In summary, removal of the olfactory bulbs appears to facilitate tonic gonadotropin secretion, such that food restriction is no longer capable of inducing testicular regression. In addition, the olfactory bulbs may have a strong influence on metabolic function in golden hamsters.

Adipose Tissue↗
PubMed1993

Olfactory bulbectomy induces reproductive recrudescence in golden hamsters on short photoperiod.

Olfactory bulbectomy results in a marked increase in gonadotropin secretion and prevents the reproductive regression associated with short photoperiod when the olfactory bulbectomy is done before exposure to the inhibitory photoperiod. The present study tested whether olfactory bulbectomy would offset the influence of short photoperiod if done after the reproductive system had regressed. Adult golden hamsters Mesocricetus auratus were divided into four groups: early sham (surgery at week-4); early olfactory bulbectomy (surgery at week-4); late sham (surgery at week 14) and late olfactory bulbectomy (surgery at week 14). At t = 0, all golden hamsters were placed in a short photoperiod (L:D 10:14). Early olfactory bulbectomy prevented testicular regression; the late olfactory bulbectomy group recrudesced much earlier than the sham groups. These results indicate that the tonic inhibitory influence of the olfactory bulbs is required for initiation of short photoperiod induced testicular regression and is also essential for the maintenance of the regressed state.

Animals↗