PubMed Health⌕ Search

Biomedical subjects

D Hampton

Publications and source records attributed to D Hampton.

At least 19 recordsLinked to original sources
PubMed2005

Deep Impact: excavating comet Tempel 1.

Deep Impact collided with comet Tempel 1, excavating a crater controlled by gravity. The comet's outer layer is composed of 1- to 100-micrometer fine particles with negligible strength (<65 pascals). Local gravitational field and average nucleus density (600 kilograms per cubic meter) are estimated from ejecta fallback. Initial ejecta were hot (>1000 kelvins). A large increase in organic material occurred during and after the event, with smaller changes in carbon dioxide relative to water. On approach, the spacecraft observed frequent natural outbursts, a mean radius of 3.0 +/- 0.1 kilometers, smooth and rough terrain, scarps, and impact craters. A thermal map indicates a surface in equilibrium with sunlight.

Jupiter↗
PubMed2001

Divalproex sodium augmentation of haloperidol in hospitalized patients with schizophrenia: clinical and economic implications.

Divalproex sodium has been approved for use in treating bipolar disorder. Its usefulness in schizophrenia has yet to be adequately assessed. Three days after initiating haloperidol treatment, patients who were hospitalized for an acute exacerbation of schizophrenia received either valproate augmentation (early-augmentation group) or continued to receive haloperidol alone (no-augmentation group). Patients in the no-augmentation group who failed to respond 14 days after the dose of haloperidol reached 20 mg/day received valproate augmentation (delayed-augmentation group). By day 14, the early-augmentation group improved 32.4% more than the no-augmentation group. Fifty percent of the patients in the no-augmentation group failed to respond to haloperidol alone for 2 weeks. They improved by 29% upon the addition of valproate. Compared with those who received no or delayed augmentation, the early-augmentation group required 44.8% fewer inpatient days from the initiation of haloperidol treatment. Patient response to treatment was particularly noted in suspiciousness, hallucinations, unusual thought content, and emotional withdrawal. Early augmentation with valproate may reduce the length of inpatient stays and provide substantially better therapeutic outcomes. It is, however, premature to recommend changes in the standard clinical management of schizophrenia on the basis of the data provided herein, in view of the small sample and open-label nature of the report.

Adult↗
PubMed2001

Cider potomania.

Explore the source record for details and available documents.

Adult↗
PubMed1998

Transient basophilia following the application of lymphatic pump techniques: a pilot study.

Lymphatic pump techniques (LPTs) consisting of pectoral traction and splenic pump were performed on seven male medical students following blood collection for baseline value determinations. Blood was collected from each subject at 15, 30, 60, 120, and 240 minutes post-LPT. The samples were analyzed for serum chemistry and complete blood cell count. All subjects showed an increase in the percentage of basophils. There was variation in the time points for the initial occurrence of basophilia among the subjects. A separate cohort of five male medical students served as control subjects. The control group did not receive LPTs. Blood samples collected at the same time points as the experimental group did not show the basophilia.

Adult↗
PubMed1996

Resolving the feeding difficulties associated with non-organic failure to thrive.

Since 1991 The Children's Society's Infant Support Project has been working in Wiltshire with the families of under 3 year olds identified as failing to thrive non-organically. Research has shown that the only common factor in children with this problem is the presence of feeding difficulties. The service concentrates on helping parents/caregivers to resolve the problems which are allowing the difficulties to continue. The multidisciplinary staff team work on a domiciliary basis, using working practices founded on social learning theory. A recent evaluation indicated that for more than two-thirds of the children with whom the project had worked, a satisfactory or very satisfactory outcome was achieved. Funding for the service is received from the Health Commission for Wiltshire and Bath, Wiltshire Social Services Department and the Children's Society.

Child Health Services↗
PubMed1996

Facilitating the recovery of open heart surgery patients through quality improvement efforts and CareMAP implementation.

OBJECTIVE: To illustrate, using a literature review and CareMAPs, how care coordination and implementation of standard protocols can impact clinical outcomes for open heart surgery patients. METHODS: A CareMAP for open heart surgery patients was developed by a multidisciplinary team. To evaluate the effectiveness of CareMAP implementation and specific quality improvement efforts, a pilot study was done that focused on increasing activity levels, decreasing ventilator time, and decreasing the frequency of arterial blood gas sampling for a sample of 55 open heart surgery patients. A rapid recovery program was developed based on the results of this pilot study. A multidisciplinary continuous quality improvement team was developed to focus on three primary areas: ventilator weaning time, activity regimens, and early transfer to the open heart surgery step-down unit. Forty-nine open heart surgery patients were included in the initial program evaluation. RESULTS: The frequency of arterial blood gas sampling decreased from an average of 5.8 per patient to an average of 3.9 per patient. Postoperative length of stay also decreased by 1.3 days for diagnosis related group 106 patients, and 3.7 days for diagnosis related group 107 patients. Results of the pilot study demonstrated additional opportunities for improving the care of open heart surgery patients. Using the rapid recovery program, the average ventilator time decreased by 4.4 hours per patient. The average postoperative length of stay decreased to 4.7 days. CONCLUSIONS: Through the quality improvement process and through the use of CareMAPs and specific protocols, the recovery of open heart surgery patients was facilitated.

Analysis of Variance↗
PubMed1995

Biomechanical properties of threaded inserts for lumbar interbody spinal fusion.

STUDY DESIGN: Calf and human cadaveric spines were used to determine motion segment stiffness and laxity after implantation of threaded inserts (the Ray Threaded Fusion Cage, Surgical Dynamics, Inc., Concord, CA), comparing direction of placement, number of implants, shape of the device, and integrity of anterior spine structures. Stiffness and laxity of spines with inserts were compared with those with bone grafts, with and without posterior fixation plates. OBJECTIVES: To determine the mechanical stabilizing properties of a threaded insert used for lumbar and lumbosacral fusion and the factors affecting stability. SUMMARY OF BACKGROUND DATA: Limited biomechanical information has shown that implantation of these devices adds stiffness to the lumbar spine, but little information is available concerning stiffness in loading directions other than flexion and extension, the effect on stiffness of position and number of implants, and the effect of this device on motion segment laxity. METHODS: Mechanical properties were determined by testing lumbar vertebral motion segments in flexion, extension, lateral bending, and torsion combined with axial compressive loading. Stiffness (slope of the load/deflection curve) and neutral zone angle or laxity (angular displacement of the vertebra from no load to 1.0 Nm moment) were determined. Initial tests were performed on calf lumbar vertebrae to determine the effects of placement and number of inserts. Comparisons of bone grafts and inserts with and without supplemental plates were made using human lumbar spines. Cylindrical- and conical-shaped inserts, when placed from anterior, were tested in calf spines. The load-bearing capacity of the insert supported in calf vertebral body bone was determined. RESULTS: There was no significant effect of placement of inserts in different orientations (lateral, posterolateral, or posterior) on stiffness, except in torsion where posterior placement damaged facets or lamina, reducing stiffness. Placement of two inserts from posterior decreased flexion and lateral bending laxity compared with the intact motion segment. Compared with intact, bone grafts produced more stiffness only in lateral bending and had no effect on laxity. Supplemental posterior plates fixed by pedicle screws across the fusion segment increased flexion and lateral bending stiffness and reduced laxity in flexion, extension, and lateral bending. Conical-shaped inserts placed from anterior into cylindrical holes distracted soft tissue structures, decreasing laxity. Cutting the anterior structures increased laxity by relieving some tissue tension caused by distraction. The mean maximum compressive load that could be supported by the insert was 2998 N (standard deviation = 980 N). Structural failure occurred in the supporting bone. CONCLUSIONS: Threaded inserts increase vertebral motion segment stiffness and decrease laxity by distracting intervertebral structures. They are not sensitive to placement, except if vertebral structures are injured during insertion and produce constructs with more consistent mechanical properties than bone grafts.

Animals↗
PubMed1993

Reduced renal hemodynamic response to atrial natriuretic peptide in elderly volunteers.

Aging is associated with decreased ability to excrete salt and water, thus increasing the susceptibility to volume overload in older individuals. Meanwhile, plasma levels of atrial natriuretic peptide (ANP) increase progressively with age for unknown reasons. We compared the natriuretic and renal hemodynamic responses to low-dose ANP infusion in an elderly group of volunteers (mean age, 74 years) with those of a group of younger subjects (mean age, 29 years). A significant reduction below baseline values in effective renal plasma flow occurred in the young group after the 2-hour peptide infusion (657 +/- 125 v 476 +/- 92 mL/min [mean +/- 1 SD]) when compared with the elderly group (two-way analysis of variance; P < 0.02). A concomitant increase in renal vascular resistance was noted in the young group only during the same period (6,631 +/- 1,384 v 9,136 +/- 2,126 dyn s cm2 x 10(6)). This increase was also significantly higher than that in the elderly group (analysis of variance; P < 0.02). Both groups demonstrated similar natriuretic responses. Absolute sodium excretion had increased significantly above baseline values in both young and elderly subjects at the end of the 2-hour peptide infusion (111 +/- 25 mumol/min to 183 +/- 33 mumol/min v 107 +/- 23 mumol/min to 198 +/- 56 mumol/min) and remained elevated until 1 hour postinfusion. We conclude that the elderly subjects in our study demonstrated a diminished renal hemodynamic response to infusion of ANP while preserving a natriuretic response similar to that found in the younger subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Failure to thrive--tackling feeding problems: a community-based approach.

Failure to thrive rings fewer alarm bells these days in comparison with other concerns such as child sexual abuse. Yet, writes Diana Hampton, it remains a significant source of anxiety to parents and professionals working in child health and development. Here she describes a Children's Society project which aims to tackle the problem of failure to thrive through one-to-one work with families in their own homes.

Child↗
PubMed1992

Renal sodium retention does not occur during the luteal phase of the menstrual cycle in normal women.

OBJECTIVE: To determine whether weight gain due to renal sodium and water retention occurs in the luteal phase of the normal menstrual cycle. DESIGN: Prospective observational study. SETTING: Research laboratory installed with modified spa bath. SUBJECTS: Ten normal healthy women. INTERVENTION: Each subject underwent two experiments, one in each phase of the menstrual cycle, involving 3 h head-out water immersion and a pre- and post immersion control hour. 25 ml blood samples were obtained every hour before, during and after water immersion. MAIN OUTCOME MEASURES: Renal and hormonal responses to water immersion during the luteal and proliferative phases of the cycle. RESULTS: There was no change in weight, creatinine clearance, basal sodium excretion or plasma atrial natriuretic peptide between the two phases of the cycle. There was a significant rise in basal progesterone, plasma aldosterone and plasma renin activity in the luteal phase of the ovulatory cycles. Renal and hormonal responses to immersion including sodium and calcium excretion, elevation of atrial natriuretic peptide (ANP) and suppression of plasma aldosterone and plasma renin activity were identical in the two phases of the menstrual cycle. CONCLUSION: We found no evidence to support the hypothesis that renal sodium and water retention occurs in the luteal phase of the normal menstrual cycle.

Adolescent↗
PubMed1992

Radioimmunoassays of arginine vasopressin and atrial natriuretic peptide: application of a common protocol for plasma extraction using Sep-Pak C18 cartridges.

A rapid vacuum-driven procedure, using pre-treated Sep-Pak C18 cartridges, has been developed for the simultaneous extraction of arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) from plasma. Non-specific interference was removed by fractional elution with an aqueous methanol/trifluoroacetic acid (TFA) mixture. AVP and ANP were coeluted under positive pressure with a methanol/TFA mixture and the eluates air-dried before measurement using separate radioimmunoassays. Assay ranges for AVP and ANP were 0.12-29.5 pmol/L and 0.65-162 pmol/L, respectively, with mean recoveries (standard deviation in parentheses) for AVP of 96.4% (5.5%) at a level of 11.8 pmol/L and for ANP of 94.8% (5.9%) at a level of 32.4 pmol/L. The extraction and assay procedures were validated by observing the changes in plasma AVP and ANP concentrations in normal subjects at different stages of hydration and in elderly patients during treatment for congestive cardiac failure.

Arginine Vasopressin↗
PubMed1990

The effect of lithium therapy on arginine vasopressin secretion and thirst in man.

Lithium therapy is known to reduce the renal responsiveness to arginine vasopressin (AVP: the antidiuretic hormone in man) and a proportion of treated patients develop polyuria and polydipsia. In this study seven nonpolyuric female patients receiving lithium treatment for an affective disorder (lithium group) were age-matched with seven healthy females (control group). The mean response of plasma AVP to osmotic stimulation was significantly enhanced in the lithium group but the mean osmotic threshold for AVP release was unchanged. Thirst appreciation in the lithium group commenced and increased overall at an osmotic stimulus 5 mmol/kg less than the control group. It is suggested that primary thirst does play a role in the expression of lithium-induced polyuria.

Adult↗
PubMed1989

Healing potential of the anulus fibrosus.

The purpose of this study was to investigate the healing of surgically created defects in the anulus fibrosus in an effort to determine the healing potential of this structure. Four identical lesions were made in the anulus fibrosus of ten dogs at levels L2-L5. Two dogs were killed at 3, 6, and 9 weeks. Four dogs were killed at 12 weeks. The spines were harvested during a 3- to 12-week period and evaluated grossly and microscopically. Our study demonstrated that a stab wound of the anulus has a limited healing potential and the persisting defect could provide a pathway for irritating nuclear fluid escape onto perineural tissue, possibly resulting in persistent low-back pain.

Animals↗