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Biomedical subjects

S Feldman

Publications and source records attributed to S Feldman.

At least 37 records · Page 2Linked to original sources
PubMed1995

The role of limbic structures in the modulation of ACTH responses following adrenalectomy.

The role of the HIPP, DF, and the lateral SPT as well as of the central AMG nucleus in ACTH hypersecretion following Adex, was studied in male rats. In animals with bilateral dorsal hippocampectomy, DF section, or SPT lesions there was a much greater increase in ACTH hypersecretion when compared to Adex alone. Implants of CS in the paraventricular nucleus of the hypothalamus prevented the rise in serum ACTH following Adex, and this effect was reversed by hippocampectomy. Bilateral lesions in the AMG prevented the Adex-induced rise of serum ACTH. These results indicate that the dorsal HIPP and its efferent pathways to the hypothalamus have normally an inhibitory effect on Adex-induced ACTH secretion. Their removal permits an elevated ACTH hypersecretion as well as attenuation of the CS feedback effect. The central AMG nucleus, which has a facilitatory effect on the hypothalamopituitary-adrenocortical axis, can also modulate ACTH secretion following Adex.

Adrenalectomy↗
PubMed1995

Posterior hypothalamic deafferentation or 5,7-dihydroxytryptamine inhibit corticotropin-releasing hormone, ACTH and corticosterone responses following photic stimulation.

The effect of posterior hypothalamic deafferentation (PHD) or hypothalamic serotonin (5-HT) depletion by 5,7-dihydroxytryptamine on corticotropin-releasing hormone (CRH), ACTH and corticosterone (CS) responses, following photic stimulation, was investigated in male rats. In intact animals, photic stimulation caused median eminence (ME) CRH depletion and a rise in serum ACTH and CS levels. In rats with PHD, in which previous studies have demonstrated 5-HT depletion, or with neurotoxin induced hypothalamic 5-HT reduction, these responses were markedly inhibited. This indicates that the blockage in the release of ME CRH into the portal circulation in rats with hypothalamic 5-HT depletion is responsible for the inhibition of the pituitary-adrenocortical responses following photic stimulation.

5,7-Dihydroxytryptamine↗
PubMed1995

Predicting endometrial cancer among older women who present with abnormal vaginal bleeding.

We studied 203 women ages 49 or over who presented with abnormal vaginal bleeding and who underwent either endometrial biopsy or dilation and curettage at the Brigham and Women's Hospital. Using information from the clinical history, we predicted their risk for endometrial cancer (36 patients) or complex endometrial hyperplasia (16 patients). Factors independently associated with endometrial cancer/complex hyperplasia included age 70 or older (OR = 9.1, P = 0.0001), diabetes (OR = 3.7, P = 0.02), and nulliparity (OR = 2.7, P = 0.02). After adjusting for age, menopause was borderline significant (OR = 2.6, P = 0.07). Our data estimated a risk of endometrial cancer/complex hyperplasia of 87% for a woman possessing all of these factors, and a risk of less than 3% if she had none of them. Our model provides an inexpensive, simple means for assessing the risk of endometrial cancer and complex hyperplasia in the post- or perimenopausal woman with abnormal bleeding.

Age Factors↗
PubMed1995

Stapled stricturoplasty for Crohn's disease. A new technique.

PURPOSE: Stricturoplasty was originally used to treat multiple fibrotic strictures of tuberculosis. As the pendulum of treatment of Crohn's disease swung toward conservatism and bowel preservation, stricturoplasty was performed in Crohn's disease. Stricturoplasty can be used when there is limited, well-localized disease and should be avoided in the presence of grossly inflamed or infected material. We describe a new technique of stricturoplasty. METHODS: Typically stricturoplasty is performed in a manner similar to a Heineke-Mikulicz pyloroplasty. A stapled stricturoplasty technique has been previously described, but in actuality these are more similar to a bypass procedure. Our technique uses a stapled, open technique similar to the triangulating method of bowel anastomosis. This was performed in one patient to correct six strictures. RESULTS: Our patient did well postoperatively and developed no significant complications. He has no evidence of recurrent strictures. CONCLUSION: We describe a stapled stricturoplasty technique that is truly a stricturoplasty because the bowel lumen is increased; it is similar to the triangulating method of end-to-end stapled bowel anastomosis. It is safe, efficient, and effective. Additionally, it allows radiographic location of the stricturoplasty site, thus allowing determination of effectiveness of the procedure as well as recurrence.

Constriction, Pathologic↗
PubMed1995

Limbic pathways and hypothalamic neurotransmitters mediating adrenocortical responses to neural stimuli.

One of the major phenomena related to the stress response is the activation of the hypothalamo-pituitary-adrenocortical (HPA) axis. This axis consists of corticotropin releasing factor-41 in the paraventricular nucleus of the hypothalamus (PVN), which in response to a variety of stimuli is released into the portal circulation and stimulates pituitary ACTH secretion and subsequently adrenocortical discharge. The mechanisms involved in the activation are not uniform and the responses to various stimuli are mediated by different neural pathways. Since extrahypothalamic limbic structures play a significant role in the HPA function, it is the purpose of this review to describe the neural pathways between the hippocampus, septum and amygdala and the hypothalamus in relation to adrenocortical activity and the differential role of the medial forebrain bundle as well as the effects of various hypothalamic deafferentation on the transmission of the neural impulses to the hypothalamus. Also, the importance of norepinephrine and serotonin in the activation of the HPA axis will be delineated.

Adrenal Cortex↗
PubMed1995

Effects of gender, pregnancy, and anesthesia on the pharmacokinetics of zidovudine in rats.

PURPOSE: The effects of gender, pregnancy and anesthesia on the pharmacokinetics of zidovudine (AZT) were studied in rats. METHODS: Unanesthetized male (MR), female (FR) and pregnant (day 20, PR) rats received 50 mg/kg AZT via a jugular vein cannula. Female (FRA), pregnant (day 20, PRA) and pregnant (day 20, PRR) rats maintained under ketamine: acepromazine:xylazine anesthesia also received 50 mg/kg AZT. Two fetuses were removed at each sampling time from the PRR group. Plasma samples were collected and analyzed by RIA. RESULTS: With the exception of a lower non-renal clearance in female rats, there were no gender differences in the disposition of AZT. No significant differences were noted in total clearance, non-renal clearance or volume of distribution between pregnant and female rats, however, significant differences in renal clearance values were evident. Anesthesia resulted in decreased total, renal and non-renal clearances in female and pregnant rats. The removal of fetuses during the experiments did not alter the total clearance of AZT in pregnant rats, however, renal clearance and volume of distribution were decreased by cesarian section. CONCLUSIONS: The rat appears to be a suitable laboratory animal model for investigating AZT disposition during pregnancy. However, results of pharmacokinetic studies when animals are maintained under anesthesia with ketamine:acepromazine:xylazine must be interpreted with caution.

Anesthesia↗
PubMed1995

Progressive outer retinal necrosis secondary to varicella zoster virus in acquired immune deficiency syndrome.

BACKGROUND: A syndrome consisting of rapidly progressive outer retinitis in patients with suppressed immune systems has been described. The etiologic agent appears to be a member of the herpes virus family. METHODS: A 41-year-old man with acquired immune deficiency syndrome (AIDS) developed bilateral outer retinitis and choroiditis, which progressed despite antiviral treatment. A transscleral eye wall biopsy specimen and whole globe were submitted for microbiologic and histologic study. RESULTS: Polymerase chain reaction of a transscleral eye wall biopsy specimen and of the enucleated specimen determined the etiologic agent to be varicella zoster virus (VZV). Histologic studies demonstrated intranuclear inclusions consistent with viral particles in choroidal cells. CONCLUSION: Our study revealed intranuclear inclusions in choroidal cells, a previously undocumented finding in progressive outer retinal necrosis. Polymerase chain reaction was very useful in identifying the causative agent.

AIDS-Related Opportunistic Infections↗
PubMed1995

Critical interaction therapy: couples therapy in combat-related posttraumatic stress disorder.

There is a need for family therapy interventions that are specific to the conditions found in families of traumatized people such as combat veterans. In these families, the historically "real" event of the trauma often continues to exert influence on the family system despite collusive arrangements that serve to keep it hidden. In families of combat veterans, a situation develops whereby the veteran becomes triangulated with a dead buddy without the spouse's knowledge. The discrepancy between past and present emerges in what we call the critical interaction between the spouses. This article outlines a method of couples therapy that attempts to demystify this critical interaction, and begins to integrate the discrepant narratives of each spouse. The establishment of a nascent mutuality of perspective within the couple releases energies that can be directed toward support rather than symptom-formation in the family system.

Combat Disorders↗
PubMed1995

Bambuterol in the treatment of asthma. A placebo-controlled comparison of once-daily morning vs evening administration.

Once-daily morning (7 AM) vs evening (10 PM) administration of the terbutaline prodrug bambuterol (20-mg tablet dose) was investigated in a double-blind, cross-over, randomized, and placebo-controlled study involving 29 diurnally active patients with asthma. Terbutaline plasma concentration, spirometry, and drug tolerance were assessed during 39-h inpatient studies. A 7-day washout period separated each treatment. Mean 24-h plasma concentration was comparable for morning and evening bambuterol (13.2 vs 14.0 nmol/L). The Cmax for evening vs morning dosing was 17.2 vs 15.5 nmol/L (p < 0.02). The 24-h mean FEV1 was greater (p < 0.001) for bambuterol (morning: 3.2 L; evening: 3.4 L) vs placebo (2.9 L) as it was for FVC, FEF25-75%, and peak expiratory flow rate (PEFR), with the maximum effect at 4 AM independent of medication time. Evening dosing, however, resulted in greatest 7 AM (awakening) FEV1, FEV25-75, and PEFR (p < 0.03). With reference to corresponding-in-time placebo values, improvement in FEV1 at the end of the 24-h dosing intervals amounted to 0.34 L (13.5%) (p < 0.0004) and 0.35 L (15.9%) (p < 0.0012) with evening and morning bambuterol dosing, respectively. Side effects were greater for bambuterol than placebo, but not significantly so. Once-daily bambuterol therapy proved to be an effective treatment for asthma, whether administered in the evening or morning. Evening dosing seems best for nocturnal asthma since airway patency overnight and on awakening at 7 AM is most improved.

Adolescent↗
PubMed1995

Antipyrine pharmacokinetics in the tail-suspended rat model.

As space flight becomes more commonplace, the influence of physiologic changes associated with the microgravity environment become of greater concern. Exposure to weightlessness has been shown to have numerous effects on body composition and organ function in animals and humans. However, studies examining possible alterations in drug metabolism and pharmacokinetics are not readily available. Antipyrine is a marker of hepatic oxidative function and total body water. The purpose of our study was to examine the effects of simulated weightlessness on the pharmacokinetics of antipyrine. Weightlessness was simulated through the use of the tail-suspended rat model. Rats were suspended for a total of 7 days. During the study period, antipyrine pharmacokinetics, after a single 20 mg/kg i.v. or p.o. dose, were evaluated at base line (day-1) and 1, 3 and 7 days after the initiation of suspension. Total body clearance was significantly elevated in the tail suspended rats from both the i.v. and p.o. dosing groups after 3 and 7 days of simulated weightlessness. In addition, clearance was elevated after 1 day of tail-suspension in the p.o. dosing group. Steady-state volume of distribution was not statistically different over the entire study period in either dosing group. Data from the present study suggest that brief periods of tail-suspension may markedly alter the pharmacokinetics of drugs in the rat and that more studies are required in models of weightlessness and actual space flight to understand the complex interaction between microgravity and hepatic metabolic activity.

Administration, Oral↗
PubMed1995

A four-year retrospective study of 3i threaded implants.

The use of osseointegrated implants can be considered as one of the most productive developments in dentistry during this century. Although initially introduced for use in fully edentulous patients, their present widespread use in nearly all forms of tooth loss, as well as for the rehabilitation of maxillofacial prosthetics and in orthodontics, has significantly expanded the realm of restorative dentistry. The present multicentre retrospective study evaluates the results of 327 patients rehabilitated with 1047, 3i (Implant Innovations Inc.) threaded implants over a four-year period. Eight patients with 22 implants dropped out and were excluded from the study as they could not be evaluated. A total of 319 patients with 1025 implants remained. Nine implants failed in the mandible and 14 in the maxilla. There was a success rate of 98.2 percent in the mandible and 97.3 percent in the maxilla. The mean overall success rate was 97.75 percent, with little variation between the four study centres. These results are similar to previously published studies on titanium threaded implants and indicate that, with careful adherence to accepted principles of surgery and restorative dentistry, the 3i threaded implant system can be used confidently to provide the necessary support for an osseointegrated implant-supported prosthesis.

Adolescent↗
PubMed1994

Differential effect of amygdaloid lesions on CRF-41, ACTH and corticosterone responses following neural stimuli.

The effect of amygdaloid (AMG) lesions on changes in median eminence (ME) CRF-41 and serum ACTH and corticosterone (CS) levels following neural stimuli were investigated in rats. In intact animals photic or acoustic stimuli caused CRF-41 depletion from the ME and a rise in serum ACTH and CS levels. In rats with medial or central AMG nuclei lesions, these responses were blocked. Basal AMG lesions were not effective. Also, all groups of animals responded normally to ether stress. These results indicate a differential effect of AMG nuclei on the hypothalamo-pituitary-adrenocortical (HPA) axis and demonstrate that the facilitatory effect of the AMG nuclei on the HPA axis responses involves the release of ME CRF-41, which stimulates ACTH and consequently CS secretion.

Acoustic Stimulation↗
PubMed1994

Measles immunization of 2-year-olds in a rural southern state.

OBJECTIVE: To assess the measles vaccine coverage of 2-year-old children living in Mississippi during the national measles epidemic of 1989 and 1990. DESIGN: Survey of 2-year-olds randomly selected from the 1987 birth cohort. The status of measles-mumps-rubella (MMR) vaccination was determined by medical record reviews and family contacts. SETTING: A predominantly rural state in the southeastern United States with a large black minority population (35%) and a low per capital income ($9827 to $12,899). Approximately 80% of MMR immunizations are given by public health service nurses working in nine health districts. SUBJECTS: A total of 2450 preschool-aged children representing 6% of the 1987 birth cohort (n = 41,279). Three hundred forty-one children were considered ineligible, leaving 2109 in the final sample. MAIN OUTCOME MEASURES: Confirmed vaccination by the age of 2 years. Rates of immunization were calculated for the entire state, its health districts, and subgroups based on population density, per capita income, type of clinic visited, and race. RESULTS: The statewide immunization rate was 87% (95% confidence interval, 86% to 88%). Among the nine health districts, rates varied from 79% to 97% (median, 88%). They were similar for white and black children in each health district and within the state as a whole. The level of vaccine coverage was significantly higher in districts with lower population densities (89% vs 85%, P = .02) and in those with higher per capita incomes (89% vs 86%, P = .03). There were four minor outbreaks of measles during 1989 and 1990; half of the cases occurred in unimmunized children too young to receive the MMR vaccine. CONCLUSION: A high rate of measles immunization is attainable among 2-year-olds living in a rural state with a large black minority population and limited economic resources.

Child, Preschool↗
PubMed1994

Small animal model of weightlessness for pharmacokinetic evaluation.

As the United States seeks a greater presence in space, physiologic changes associated with space flight become of greater concern. Exposure to a weightless environment has been shown to have numerous effects on body composition and organ function. Alterations include decreases in muscle and liver mass, changes in bone structure and integrity, and fluid shifts markedly affecting cardiovascular functioning. Furthermore, metabolic activity of the liver has been found to be altered in rats after extended periods of weightlessness. As the length of space travel increases, the probability for the need to administer pharmacologic agents to crew members during space flight for prophylaxis or treatment becomes greater. Thus, because of the observed physiologic and metabolic changes associated with weightlessness, it is reasonable to assume that the pharmacokinetics and pharmacodynamics of xenobiotics administered during space flight may be different that those found in 1g environment. To address these possible changes, the development of a model of weightlessness to investigate possible alterations in drug pharmacokinetics and pharmacodynamics before space flight is of importance. The tail-suspended rat is a well-described model of weightlessness. During the time of the suspension, the pharmacokinetics of marker compounds can be used to evaluate changes in hepatic and renal physiology. Rats suspended for different periods allow for the investigation of the length of weightlessness exposure and drug pharmacology. Results from the use of the suspended rat model provide valuable information regarding possible pharmacokinetic and pharmacodynamic changes associated with weightlessness, and therefore, provide space biomedical researchers with a method of investigating drug administration during space flight missions.

Animals↗
PubMed1994

Two-year follow-up of 263 patients with post/perimenopausal vaginal bleeding and negative initial biopsy.

Patients with post- or perimenopausal bleeding (PMB) whose initial endometrial biopsy or dilation and curettage (D&C) reveals benign or insufficient tissue may eventually be diagnosed with endometrial cancer or complex endometrial hyperplasia. We studied 286 consecutive patients with PMB who had either an endometrial biopsy or D&C at Brigham and Women's Hospital during November 1990 to April 1991 and reviewed their subsequent specimens after a minimum of 23 months of follow-up. Of the initial 286 patients with PMB, 6 (2%) had endometrial cancer on their index biopsy, 17 (6%) had complex hyperplasia, and 201 (70%) had other benign findings. Sixty-two (22%) had "tissue insufficient for diagnosis." Excluding the 23 with cancer/complex hyperplasia, there were 263 patients in the cohort, 86 of whom (33%) had further endometrial sampling during the follow-up period. Of these, four (2%) were subsequently found to have a uterine malignancy (2 of the benigns, 2 of the insufficients) and five (2%) were subsequently found to have complex hyperplasia. Of the four patients subsequently found to have cancer, two had stage I adenocarcinoma, one had stage IV adenocarcinoma, and one had stage I high-grade stromal sarcoma.

Aged↗