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Biomedical subjects

E F Bond

Publications and source records attributed to E F Bond.

At least 19 recordsLinked to original sources
PubMed1998

Estrogen suppresses gastric motility response to thyrotropin-releasing hormone and stress in awake rats.

Symptoms associated with gastric motility alteration vary with stress and ovarian hormone status, most notably in women with irritable bowel syndrome. This study examines combined effects, comparing gastric motility during administration of a stress-related neuropeptide thyrotropin-releasing hormone (TRH) and restraint stress in conscious rats of varied ovarian hormone status. Adult rats were ovariectomized and implanted with estrogen, progesterone, or vehicle-releasing pellets. After 21 days, intracerebroventricular (i.c.) cannula and gastric tension transducer were implanted. After 25-27 days, motility was recorded during neuropeptide injection (TRH/saline i.c.) or restraint stress. TRH induced increased motility in all groups; the response varied with hormone group, and was least and briefest in estrogen-treated rats. Motility during restraint varied with hormone group; it was diminished in estrogen-treated but not other groups. Ovarian hormone status (estrogen) modifies gut response to TRH and restraint stress.

Animals↗
PubMed1998

Evidence for autonomic nervous system imbalance in women with irritable bowel syndrome.

Autonomic nervous system function was assessed in women with and without irritable bowel syndrome using frequency domain measures of heart rate variability. Women were interviewed and placed into the irritable bowel syndrome (N = 25) group based on history of diagnosis and self-report of current gastrointestinal symptoms. Women in the control group denied a history of chronic gastrointestinal symptoms (N = 15). Women were followed for one menstrual cycle with a symptom diary, and during mid-luteal phase they wore a Holter 24-hr electrocardiograph monitor. Women with irritable bowel syndrome demonstrated significantly lower vagal tone as measured by the high frequency spectrum relative to control women. In addition, women with irritable bowel syndrome had a flattened 24-hr pattern of heart rate variability, with significantly lower levels of vagal tone during sleep. These results suggest that systemic sympathovagal balance may be shifted in a subset of women with irritable bowel syndrome.

Adult↗
PubMed1996

Advancing nursing practice: acute care nurse practitioners meet challenges at and beyond the health care horizon.

Preparation of advanced practice nurses (APNs) with acute care skills relevant to today's health care environment is a challenge faced by nurse educators, care providers, professional organizations, and regulatory agencies. The acute care nurse practitioner (ACNP) is prepared to provide multidimensional, risk-appropriate management of medically vulnerable patients with serious illness in a variety of settings. ACNPs conduct comprehensive health assessments, order and interpret diagnostic tests, diagnose and manage health problems and disease-related symptoms, prescribe and evaluate drugs and treatments, and coordinate care during setting transitions. Working independently and collaboratively the ACNP enhances access to care and quality of care for patients and families through cost-effective, outcome-oriented practice. This article describes health care market factors fostering ACNP practice, ACNP practice domain, the University of Washington ACNP program, and collaborative contributions from educators, care providers, professional organizations, and regulatory groups needed to implement the role.

Acute Disease↗
PubMed1995

Gastric motility in rats with varying ovarian hormone status.

Gastrointestinal (GI) symptoms suggestive of altered motility vary with menstrual cycle phase and menopause, but the effects of ovarian hormones on gastric motility have not been described. Basal and stimulated gastric motility were studied in male and female rats that were ovariectomized and implanted with continuous-release progesterone and/or estrogen pellets. Following 26 days of hormone treatment, rats were implanted with a gastric tension transducer. Contractile activity was recorded, then thyrotropin-releasing hormone (TRH) or saline was injected intracisternally and motility was monitored. An index was calculated based on frequency and amplitude; response to TRH was expressed as percentage of the basal index. Basal contraction frequency was highest in the estrogen and estrogen+progesterone groups. Hormone treatment significantly affected the TRH-stimulated motility index; TRH induced increased motility in all groups, with larger, more sustained responses in vehicle, progesterone, and male groups. Results demonstrate the ovarian hormone modulation of basal and stimulated gastric motility. Such modulation may contribute to changes in GI symptoms with altering ovarian hormone state.

Animals↗
PubMed1994

Comparison of diet composition in women with and without functional bowel disorder.

Nurses are often involved in helping patients alleviate chronic distressing gastrointestinal symptoms such as those associated with irritable bowel syndrome or functional bowel disorder. One therapeutic strategy is to increase dietary fiber intake and to eliminate gastrointestinal (GI) irritants such as caffeine, alcohol, and tobacco smoking. However, little work has been done to establish a relationship between dietary factors and chronic GI symptoms. In this article, the authors: (a) describe and compare caloric and dietary constituent intake in symptomatic (n = 18) and asymptomatic (n = 37) women, and (b) examine the relationships among diet, GI symptoms, and stool characteristics in the two groups. In particular, total calories, fiber, fat, protein, and carbohydrates as well as alcohol and caffeine intakes were compared in women who do not smoke. Because menstrual cycle phase modulates both symptoms and appetite, women were studied during the follicular phase. Groups had similar caloric, fat, and protein intakes. Fiber intakes were similar and similar to national norms in both groups. When compared with asymptomatic women, the symptomatic women consumed more refined carbohydrates. Relationships were observed among dietary intake of refined carbohydrates, fiber, GI symptoms, and stool characteristics in women with functional bowel disorder.

Adult↗
PubMed1994

Shivering following cardiac surgery: predictive factors, consequences, and characteristics.

BACKGROUND: Shivering is common after cardiac surgery and may evoke harmful hemodynamic changes. Neither those changes nor factors increasing probability of shivering are well defined. OBJECTIVES: (1) To identify factors linked with risk of shivering by comparing age, weight, body surface area, gender, intraoperative details, anesthetics, postoperative temperatures, hemodynamics, and therapeutics in shivering vs nonshivering patients. (2) To describe temperatures, hemodynamics, therapeutics, myocardial oxygen consumption correlates (rate-pressure product, heart rate, systemic vascular resistance) in shivering and nonshivering groups, and shivering and nonshivering periods. (3) To characterize the electromyogram to determine whether the tremor is cold-induced. METHODS: A descriptive design with a time series component was used to study a convenience sample of 10 shivering and 10 nonshivering adults for 4 hours during early recovery from cardiac surgery. Pulmonary artery and skin (facial, calf, trunk) temperature were measured every 60 seconds; heart rate and arterial pressure, every 15 minutes; cardiac output, 3 times. Electromyogram was recorded intermittently. Medications and treatments were noted. RESULTS: Lower skin temperature was significantly related to shivering risk. Heart rate was significantly higher initially in shiverers and remained higher by 13.6 beats per minute. Significantly more nitroprusside was used to control arterial pressure before than after shivering. No significant differences were noted between groups in core temperature, age, weight, body surface area, anesthesia type, intraoperative temperature; or surgery, circulatory bypass, or cardiac cross-clamp duration. The electromyogram pattern during shivering was typical of that produced by cold. CONCLUSIONS: These results suggest that true shivering occurs after cardiac surgery. Skin, but not core, temperature and elevated heart rate predict shivering. Shivering may be more likely in hemodynamically unstable patients.

Adult↗
PubMed1993

Insulin-induced membrane changes in K(+)-depleted rat skeletal muscle.

Insulin-induced membrane changes were investigated in K(+)-depleted rat muscle. Male Sprague-Dawley rats were placed on a K(+)-free but otherwise adequate diet for 5-8 wk; serum K+ concentration ([K+]) dropped to 1.2-3.2 mM. Omohyoid membrane potential was -81 mV in 5.5 mM [K+] (SO4(2-)). Exposure to either insulin or low (0.5 mM) [K+] singly changed potential only slightly. The combination resulted in depolarization of 90% of fibers (-43 mV) and hyperpolarization of 10% of fibers (-101 mV). Fibers from normokalemic rats did not depolarize. Tetrodotoxin (TTX) blocked depolarization, implying the presence of noninactivating TTX-sensitive Na+ channels. K+ currents were measured using the three-electrode voltage clamp; movement of other ions was prevented by ion substitution, channel blockers, and depolarization-induced channel inactivation. K+ conductance was similar in control fibers with or without insulin. In the absence of insulin, currents in K(+)-depleted fibers were offset by a large leakage current that was significantly diminished when insulin was present. The insulin-induced current decrease was observed in nitrendipine, suggesting that the apparent decreased outward current was not an inward current carried by Ca2+. Data are consistent with altered Na+ and K+ channels in K(+)-depleted muscle, i.e., insulin-related closing of K+ channels initiates depolarization, which is then sustained by opening of noninactivating Na+ channels.

Animals↗
PubMed1992

Mediation of thyrotropin-releasing hormone induced gastric motility increases in developing rats.

Centrally administered thyrotropin-releasing hormone (TRH) induces vagally mediated gastrointestinal effects which may be cholinergic, serotonergic or a combination. This study investigated mediation of TRH-stimulated gastric motility in developing rats. A serotonin (5-HT) antagonist (5-HT2, ketanserin or xylamidine; 5-HT3, MDL 72222) or an acetylcholine receptor blocker (atropine) was administered intraperitoneally 30 min prior to intracisternal TRH (5-10 micrograms). The 5-HT-depleting para-chlorophenylalanine (p-CPA) was administered 48 or 72 h prior to TRH. Gastric motility, monitored via extraluminal strain gauge, was not increased with TRH in atropine-pretreated rats. MDL 72222 had a significant age-related effect on TRH-induced gastric motility increases while 5-HT2 antagonists and p-CPA treatment did not. Thus, acetylcholine receptor blockade inhibits TRH-stimulated gastric motility in young and adult rats while 5-HT3 antagonism eliminates the motility response in young (7 and 10 days) rats.

Aging↗
PubMed1992

A possible 5-HT3 component of thyrotropin-releasing hormone-induced increases in gastric motility in developing rats.

Intracisternal injection of thyrotropin-releasing hormone (TRH) increases gastric motility primarily via a vagal cholinergic mechanism. However, a serotonergic (5-HT) component may also exist. Rats (7, 10, 14, and > or = 50 days of age) were anesthetized and gastric motility monitored via an extraluminal strain gauge. Following baseline, ICS 205-930 which blocks 5-HT3 and 5-HT4 receptors (0.01, 0.10, or 1.0 mg/kg) was administered intraperitoneally, then 30 min later intracisternal TRH (5 or 10 micrograms). ICS 205-930 0.1 and 1.0 mg/kg blocked TRH-induced motility in 7-day-old rats. Results support a 5-HT3 or 5-HT4 receptor contribution to TRH-induced gastric motility stimulation, and suggest that receptor expression is dynamic during development.

Animals↗
PubMed1991

Morphine inhibits TRH-induced gastric contractile activity.

This study investigated the effect of centrally and peripherally administered thyrotropin releasing hormone (TRH) on gastric contractile activity of rats 14, 21, 28 and adult (greater than or equal to 50) days (D) of age, and the effect of morphine pretreatment on that response. Rats were anesthetized with urethane, then a tension transducer was implanted on the anterior gastric corpus. Following baseline recording, rats were pretreated with intraperitoneal morphine (2 mg/kg). TRH (5 micrograms) in saline or saline alone (0.6 microliters) was then injected into the cisternum magnum. Additionally, dose response to TRH was examined in 14- and 50-day-old rats. Intracisternal TRH induced a dose-related increase in gastric contractile activity in both 14- and 50-day-old rats. Higher doses of TRH (10 and 30 micrograms) prolonged the response as compared to low doses. Peripheral morphine pretreatment blocked the TRH-induced increase in gastric contractile activity in all age groups although a higher morphine dose (10 mg/kg) was needed to block the effect in 28D rats. Intravenous TRH (5, 10, 30 micrograms) produced an increase in gastric contractile activity in 14D rats which was blocked by vagotomy.

Animals↗
PubMed1990

Age-related variations in jejunum and distal colon contractile response to thyrotropin-releasing hormone in vitro.

The effects of thyrotropin-releasing hormone (TRH) on the contractile activity of the proximal jejunum and distal colon of 3-, 7-, 14-, 21-, 28-, 50-day-old and adult male Sprague-Dawley rats were examined. Longitudinal segments were mounted in force displacement transducers and bathed in oxygenated, buffered Krebs' solution. In the proximal jejunum TRH 10(-6) M produced a tetrodotoxin (TTX)-sensitive tension increase in 3- to 14-day-old rats and a TTX-resistant biphasic response in older rats. TRH 10(-6) M produced a transient tension in the distal colon of rats less than or equal to 21 days old. Incubation with TRH 10(-6) M for 30 min increased responsiveness to acetylcholine 10(-7) M in approximately 50% of tissues studied. Direct and indirect effects of TRH are developmentally determined.

Acetylcholine↗
PubMed1981

A new approach to the study of the E. coli nucleoid.

E. coli were examined by the freeze-fracture thaw-fix technique, embedded in thin fibrin gels. After glutaraldehyde fixation the bacterial nucleoid was found spread out over the surrounding fibrin. Addition of calcium and uranyl acetate to the fixative preserved the nucleoid in compact form. The spread nucleoid was then examined against a smooth mica background after freeze-thaw and osmotic lysis. These spreads were critical-point dried, rotary shadowed with platinum-carbon and viewed as stereo-pair micrographs. Structures seen are tentatively interpreted as clusters of polyribosomes, extended DNA, and supercoiled DNA complexed with proteins or polyamines. After osmotic lysis, glutaraldehyde alone preserves the nucleoid in compact form. Only where strands are broken, in freeze-fracture or freeze-thaw lysis, must uranyl acetate be added to the fixative to preserve a compact structure.

Bacterial Proteins↗
PubMed1979

Three-dimensional view of the chromatin in freeze-fractured chicken erythrocyte nuclei.

The freeze-fracture thaw-fix (FfTF) technique described in earlier papers is applied in the present work to more detailed study of the chicken erythrocyte, by transmission replicas and high resolution scanning electron microscopy (3 nm scan beam size). The three-dimensional structure of the chromatin, and possibly the non-histone protein matrix, of fractured nuclei is to a large extent retained in this method of preparation and seen in stereomicrographs. In these micrographs the helical sub-structure of the 25 nm chromatin strands can be seen at about the same resolution as that of previously published micrographs in which extracted chromatin is viewed by negative contrast or after metal shadowing. The useful resolution of the secondary electron micrographs, for a suitably mounted specimen, is shown to be as good as that of transmission micrographs of platinum-carbon replicas of the same material.

Animals↗
PubMed1976

Improved resolution in cathodoluminescent microscopy of biological material.

This paper continues work reported in an earlier paper on modification of a Cambridge Stereoscan Mk IIA to improve the quality of cathodoluminescent micrographs of biological material. In the work presently described the microscope gun has been offset laterally by 2 mm, to prevent light from the filament passing down through the column to the specimen chamber. The electron beam is brought onto the column axis by deflection coils. This modification effectively eliminates background light in the chamber, and a full parabolic mirror is fitted to maximize light collection. Results for yeasts and wheat seed sections are described.

Microscopy, Electron, Scanning↗