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Biomedical subjects

B D White

Publications and source records attributed to B D White.

At least 55 records · Page 3Linked to original sources
PubMed1993

The effects of brace position on injuries sustained in the M1 Boeing 737/400 disaster, January 1989. NLDB Study Group.

Of the initial 87 survivors of the East Midlands Boeing 737/400 aircraft, 77 sustained head and facial trauma during the crash, 45 of whom were rendered unconscious. There were 21 who received injuries to the back of their head, including 5 of the 6 severely head-injured adults. Those passengers who adopted the fully flexed "brace" position for crash-landing achieved significant protection against head injury, concussion, and injuries from behind irrespective of local aircraft structural damage. A computer graphics simulation developed by a commercial firm (H. W. Structures, Ltd.) using the predicted crash pulse of the accident has validated these clinical findings and allows theoretical biomechanical modeling for the design of occupant protection systems in the future. Although the major role of structural failure should not be forgotten, bracing maximizes the chance of uninjured survival in the current generation of aircraft and should be demonstrated and practiced as a pre-flight routine.

Accidents, Aviation↗
PubMed1993

The effects of structural failure on injuries sustained in the M1 Boeing 737 disaster, January 1989. NLDB Study Group.

Only 10 occupants escaped uninjured from the wreckage of the East Midlands Boeing 737/400 aircraft accident. The remaining 116 suffered injuries similar in pattern, but ranging in severity from simple bruising to fatal crushing trauma. Overall, the individual's degree of injury and likelihood of death was proportional to the local structural damage of the aircraft. Limb injuries were particularly severe in the forward section of the wreckage where the floor failed. In areas where structural damage appeared to be survivable, a number of passengers suffered disproportionately severe head injuries. Many of these had trauma to the posterior aspect of their head, some of whom died as a result. It is likely that these injuries were caused by falling overhead lockers or unrestrained cabin furniture. The significance of these injuries and their future prevention is discussed.

Abbreviated Injury Scale↗
PubMed1992

Clinical significance of pneumatosis of the bowel wall.

The presence of gas within the bowel wall is an uncommon condition that is typically first diagnosed by the radiologist. Although it is often seen on abdominal radiographs, computed tomography is more sensitive in demonstrating pneumatosis and its complications. There is a spectrum of disease states that produce this abnormality, ranging from the innocuous to the fatal. Its radiographic appearance is variable, particularly the location, extent, severity, and presence of pneumoperitoneum or portal venous gas. None of these imaging characteristics can be considered pathognomonic for the underlying cause of the pneumatosis. The radiologist must be aware of the different conditions associated with this entity, as well as their variable appearances.

Humans↗
PubMed1991

Variation in T-lymphocyte activation and susceptibility to SIVPBj-14-induced acute death in macaques.

In contrast to pig-tailed and cynomolgus macaques, which die in 6-10 days following infection with the SIV-PBj-14 isolate, only about 50% of rhesus succumbed to rapid disease. Using a CD45RA MAb that delineates memory (CD45RAlo), naive (CD45RAmed) and "activated" (CD45RAhi) T-cell subsets, it was seen that PBMC from pig-tailed and cynomolgus monkeys, unlike rhesus, have reduced CD4/CD8 ratios and a skewing of T cells towards CD45RAhi expression. Such preactivation of CD4+ cells could lead to enhanced viral replication and early death.

Acute Disease↗
PubMed1991

Red eyes and red rash with fever: an uncommon initial presentation for staphylococcal obturator abscess with adjacent ischial osteomyelitis.

"Red eyes and red rash with fever" is a common pediatric complaint; however, it is an uncommon initial presentation for staphylococcal obturator abscess with adjacent ischial osteomyelitis. The case of a 13-year-old boy who was admitted to the hospital with conjunctivitis, erythematous maculopapular lesions, and fever and had this final diagnosis is reported. The differential diagnosis included various bacterial diseases, several viral illnesses, and rickettsial disease.

Abscess↗
PubMed1991

What does Cruzan mean to the practicing physician?

The United States Supreme Court's recent decision in the Cruzan case declared that the states have broad powers to formulate their own rules in "right to die" cases. The Court held that competent adults have a constitutionally protected "liberty interest" that allows them to accept or refuse medical treatments. Since liberty interests are subject to rational state regulation, the narrow holding in Cruzan affirmed Missouri's authority to require a "clear and convincing" evidence standard to determine a patient's wishes before life-sustaining treatment could be withdrawn from a formerly competent adult now in a persistent vegetative state. For practicing physicians, some of the implications of Cruzan are as follows: (1) For competent adult patients, physicians should respect patient wishes regarding life-sustaining treatment. (2) Physicians also should discuss with competent patients their wishes for life-sustaining treatment at a future time, when a patient may no longer be able to participate in such decisions. (3) Physicians should record these wishes in a legally acceptable instrument that addresses two aspects of care that may arise in the future if the patient becomes incompetent. What would the patient want done? Who would the patient wish to designate as a surrogate or proxy? (4) For patients who are now incompetent, but for whom decisions must be made about life-sustaining treatment, physicians should focus on the previously expressed wishes of the patient rather than on the patient's current quality of life or on the wishes of the patient's family.

Advance Directives↗
PubMed1990

Alterations in the binding characteristics of glucocorticoid receptors from obese Zucker rats.

Obese Zucker rats appear to lack a circadian rhythm of serum corticosterone and maintain relatively high concentrations throughout the 24-h day. The binding characteristics of glucocorticoid receptors in lean and obese Zucker rats were examined in three tissues suggested to be involved in the feedback inhibition of corticosterone: the anterior pituitary, hypothalamus and hippocampus. Hepatic glucocorticoid receptors were also examined to determine if receptor alterations exist in a peripheral tissue. The dissociation constant (Kd) of glucocorticoid receptors in the anterior pituitary of obese rats was 50% greater than the Kd of receptors derived from lean rats. This suggests a decrease in the affinity of these receptors and could indicate a reduced feedback inhibition of corticosterone at the anterior pituitary. Hepatic glucocorticoid receptors of obese rats also showed an increase (150%) in the Kd of binding and a reduction (40%) in the number of receptors. No difference was observed in the Kd or maximal binding of receptors from the hypothalamus or hippocampus of lean and obese rats. It appears that glucocorticoid receptor alterations exist in obese Zucker rats and that these alterations may affect the drive of the pituitary-adrenal axis and possibly the expression of obesity.

Animals↗
PubMed1990

Neuropeptide Y expression in rat brain: effects of adrenalectomy.

Neuropeptide Y (NPY) messenger RNA was measured by hybridization of mRNA from the cortex, hippocampus, hypothalamus and striatum of rat brains. Adrenalectomized rats showed lowered level of NPY message in the striatum. A similar decline was found in the hypothalamus, while the cortex and hippocampus were unchanged. Levels of NPY message per unit total RNA were about the same for hypothalamus, cortex and striatum and about 50% less for hippocampus. Adrenalectomized rats that received replacement corticosterone had levels of NPY message that had returned to the levels found in rats receiving sham operation. Response elements consistent with our findings are reported in the NPY genomic sequence.

Adrenal Glands↗
PubMed1990

Adrenalectomy decreases neuropeptide Y mRNA levels in the arcuate nucleus.

Recent studies suggest that glucocorticoids may increase NPY and NPY mRNA levels. To determine if endogenous corticosterone affects the level of NPY mRNA in areas that control NPY levels in the paraventricular nucleus, we examined the effects of adrenalectomy and corticosterone replacement on NPY mRNA levels in the arcuate nucleus and brainstem. Rats were either adrenalectomized, adrenalectomized and corticosterone replaced, or sham-operated. The arcuate nucleus, hypothalamus (excluding arcuate nucleus), and brainstem were collected and the RNA isolated. Dot blots were made of each tissue and the NPY mRNA quantitated by densitometry. Adrenalectomy significantly reduced NPY mRNA levels in the arcuate nucleus, while corticosterone replacement restored the NPY mRNA levels. NPY mRNA levels in the remainder of the hypothalamus were not affected by adrenalectomy. Adrenalectomy also had no affect on NPY mRNA levels in the brainstem. These data suggest that the paraventricular nucleus may be affected by glucocorticoids via an NPY pathway and that the two major afferent pathways of NPY-containing neurons to the paraventricular nucleus may be regulated by different mechanisms.

Adrenal Glands↗
PubMed1990

A clinical survey of head injuries sustained in the M1 Boeing 737 disaster: recommendations to improve aircrash survival.

On 8 January 1989 at 20:25 h, a British Midland Boeing 737/400 on approach to East Midlands Airport crashed across the M1 motorway with the immediate loss of 39 lives from the 126 people on board. In the aftermath of the accident a clinical review was commenced to determine the mechanisms of injury in the 87 initial survivors and hopefully provide data to improve commercial aircraft safety in the future. Seventy-seven survivors sustained head and facial trauma in the crash, 45 of whom had periods of amnesia surrounding the event. Twenty-one received injuries from behind, including five of the six severely head-injured adults. Loss of consciousness and duration of amnesia were directly related to the degree of superficial head trauma. Adoption of the fully flexed brace position for crash-landing offered significant protection from head injury and concussion, and possibly reduced injuries from behind. Suggestions are made for potentially improving the survivability of aircraft accidents.

Accidents↗
PubMed1989

The metabolic clearance rate of corticosterone in lean and obese male Zucker rats.

The obese Zucker rat is an animal model of human juvenile-onset obesity. These rats exhibit numerous endocrine and metabolic abnormalities. Adrenalectomy of obese rats has been shown to reduce or reverse several of these abnormalities, thereby implying that corticosterone may contribute to the expression of obesity in this animal. Furthermore, it has been shown that the circadian rhythm of plasma corticosterone is disturbed in obese Zucker rats resulting in elevated morning plasma corticosterone concentrations in obese rats as compared to lean rats. In a effort to better elucidate the mechanism of the elevated morning levels of plasma corticosterone, the metabolic clearance rate of corticosterone was determined in the morning for lean and obese male Zucker rats (12 to 20 weeks). Additionally, the biliary and urinary excretion of labeled corticosterone and/or its metabolites were determined. The metabolic clearance rate of corticosterone was significantly greater in obese rats than in their lean counterparts. Both the metabolic clearance rate and the volume of compartments significantly correlated with body weight. No correlation was found between body weight and the elimination rate constant. The increased metabolic clearance rate of obese rats appeared to be due to an increase in the physiologic distribution of corticosterone and not to an alteration in the enzymes responsible for corticosterone metabolism. It appears that the metabolic clearance rate of corticosterone in obese Zucker rats does not contribute to elevated morning concentrations of plasma corticosterone previously observed in these animals. It suggests that the adrenal corticosterone secretion rate must actually be greater than one would expect from the plasma corticosterone concentrations alone.

Animals↗
PubMed1989

Wound perfusion with bupivacaine: objective evidence for efficacy in postoperative pain relief.

Conflicting reports exist for the efficacy of intermittent wound perfusion with bupivacaine in the relief of postoperative pain. A study was devised to assess postoperative pain relief objectively using a Patient Controlled Analgesic Device (PCAD) during continuous wound perfusion with bupivacaine or saline. Thirty consecutive patients undergoing cholecystectomy were randomised to receive continuous postoperative wound perfusion with 0.5% bupivacaine for 24 h followed by normal saline for a further 24 h or vice versa. During the study period, conventional analgesia was provided using a PCAD set to deliver (and record the number of) on-demand bolus doses of intravenous pethidine 0.2 mg/kg at half-hourly intervals as required. Pethidine requirements were higher on the first postoperative day, regardless of which solution was given, but bupivacaine perfusion almost halved mean linear analogue pain scores compared to those recorded with saline. Likewise, the number of bolus doses of pethidine demanded was reduced by an average of 68% compared to those recorded during saline perfusion on day 1 (P = 0.01) and by 82% on day 2 (P = 0.01). When assessed by objective criteria, perfusion of surgical wounds with bupivacaine after cholecystectomy produces better pain relief than wound perfusion with saline.

Administration, Topical↗
PubMed1988

Responsiveness of isolated adrenocortical cells from lean and obese Zucker rats to ACTH.

Morning plasma corticosterone concentrations have been reported to be elevated in obese Zucker rats compared with lean rats. The aim of this study was to determine if differences in adrenal sensitivity or maximal responsiveness to adrenocorticotropic hormone (ACTH)-(1-24) could account for this disparity. Serum and adrenal glands were collected from lean and obese, male and female Zucker rats (10-13 wk old) between 10:00 and 11:00 A.M. Adrenocortical cells were isolated and challenged with ACTH-(1-24). The serum corticosterone and ACTH concentrations were significantly greater in obese males compared with lean males (45.3 +/- 10.3 vs. 23.2 +/- 1.45 ng/ml and 156.6 +/- 15.3 vs. 113.3 +/- 9.4 pg/ml, respectively). Although serum corticosterone concentrations were similar in female rats, serum ACTH concentrations tended (P = 0.07) to be lower in obese female rats than in lean female rats (67.6 +/- 9.3 vs. 103.5 +/- 15.1 pg/ml, respectively). The median effective concentration (EC50) and the maximal corticosterone response per microgram of DNA of dose-response curves derived from lean and obese rats were not significantly different. Additionally, a morphometric evaluation of adrenal tissue from lean and obese rats suggested that cells of the zona glomerulosa were smaller in obese rats than in lean rats. Our data confirm that morning serum corticosterone concentrations are elevated in 10- to 13-wk-old male Zucker rats. This difference does not appear to be due to differences in the sensitivity or maximal secreting capacity of adrenocortical cells to ACTH.

Adrenal Cortex↗
PubMed1984

Measures of care.

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Delivery of Health Care↗