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Biomedical subjects

J Sullivan

Publications and source records attributed to J Sullivan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Phylogeography of Peromyscus furvus (Rodentia; muridae) based on cytochrome b sequence data.

We conducted phylogenetic analyses of cytochrome b sequence data to assess genetic variation within and among the three allopatric segments of the distribution of Peromyscus furvus from the Sierra Madre Oriental in eastern Mexico. We identified 24 unique haplotypes among the 54 individuals examined and genetic distances ranged up to 0.078 substitutions per site. Populations from the central portion of the range formed a monophyletic unit, whereas samples from the southern distributional unit were polyphyletic. Furthermore, the southernmost population sampled may represent a distinct species. This high degree of genetic differentiation among populations, currently recognized as conspecific, mirrors the result of other genetic studies of highland rodents in Mesoamerica. Together these studies indicate that the region, already considered hyperdiverse on the basis of species diversity and endemism, may contain considerably greater diversity than is currently appreciated.

Animals↗
PubMed2000

Role of stored iron in atherosclerosis.

Myocardial infarction remains the No. 1 killer of American men and women, with a death rate of 225,000 per year, and stroke, the third leading cause of death in the United States, afflicts about 600,000 per year. The combined financial burden of these diseases is approximately $134 billion per year. Therefore, interventions that reduce mortality and suffering will have a significant impact on the health care system. This article summarizes research conducted during the last 2 decades that addresses the idea that stored iron plays a role in the pathogenesis of atherosclerosis and that iron reduction through phlebotomy may play a role in the treatment or prevention of atherosclerosis. Body iron stores rise after adolescence in men and menopause in women. This rise has been linked to the pathogenesis of atherosclerosis through iron-induced oxidation of low-density lipids and foam cell formation. However, the available evidence on the iron hypothesis remains circumstantial. Reduction of body iron stores in the setting of a controlled, prospective intervention trial is necessary to determine whether the amount of stored iron is related to clinically meaningful vascular disease. Such a study is feasible because reduction in iron stores can be achieved safely and predictably without induction of iron deficiency by graded phlebotomy. The Iron and Atherosclerosis Study (FeAST), a Veteran's Administration Cooperative Study, is under way to test this concept.

Arteriosclerosis↗
PubMed2000

Positioning of patients with severe traumatic brain injury: research-based practice.

Traumatic brain injuries (TBIs) are the most common disabling injuries in the United States, accounting for 44% of all deaths due to trauma. Once inflicted, primary cerebral injury is immutable and irreversible. Consequently, initial critical care of TBI patients focuses on prevention of secondary cerebral injury through the treatment of intracranial hypertension, systemic resuscitation, and multisystem stabilization. Relationships exist between therapeutic positioning, multisystemic stability, and prevention of secondary cerebral injury in severe TBI. A critical review and synthesis of current research literature on multisystem responses to positioning led to development of clinical recommendations based on currently available evidence and generated best practices for positioning patients with severe TBI.

Bed Rest↗
PubMed2000

Evaluating the role of physical and radiographic examinations in assessing bullet tract termination for gunshot victims.

Knowledge of the path of a bullet and how it terminates is critical for expeditious assessment and optimal management of patients with gunshot wounds. To assess the accuracy of physical examination and X-rays in these patients, a prospective study was undertaken for all gunshot victims seen for a 1-year period on a single trauma service. The paramedics and trauma surgeons' physical examinations were evaluated for whether a bullet tract could be accurately categorized as 1) through and through, 2) graze, 3) palpable under dermis, or 4) retained (ie, not palpable). The impact of X-rays was assessed with regard to how it affected the trauma surgeons' categorization. A total of 78 patients were seen with a total of 120 bullet tracts. Seventy-seven per cent were injured by assault, and 64 per cent were shot with a 9-mm or .38-caliber handgun. Twenty of 60 (33%) bullet tracts on the torso terminated with a missile that was palpable under dermis, but only 2 of 10 neck (20%), 1 of 28 extremity (4%), and 1 of 22 head/face (5%) did so. Paramedics evaluated 15 torso bullet tracts that ended palpable under dermis, of which they detected 5 (33%). Upon initial examination, the trauma surgeon detected 11 of 20 torso bullet tracts that ended palpable under dermis (55%), and detected 14 of the 20 after X-rays were done (70%). Overall, obtaining X-rays changed the categorization for 15 of 111 bullet tracts (13%). We conclude that bullet tracts on the torso result in a subcutaneously palpable bullet one-third of the time, much more frequently than in other body regions. Paramedics only detect one-third of subcutaneously palpable missiles on the torso. X-rays change the categorization of bullet tracts infrequently. We recommend that a careful examination of the skin of the torso to detect palpable missiles be incorporated into the secondary survey of patients with wounds to that body region.

Allied Health Personnel↗
PubMed2000

Transurethral resection of the prostate: failure patterns and surgical outcomes in patients with symptoms refractory to alpha-antagonists.

BACKGROUND: alpha-Antagonists (AAs) are ineffective in some men with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Transurethral resection of the prostate (TURP) may be required. Reasons for AA failure and surgical outcomes in these patients have not been reported. METHODS: We retrospectively reviewed cases of TURP for LUTS due to bladder outlet obstruction from 1995 to 1998. The TURP patients in whom AA therapy had failed (group 1) were compared with those who had symptomatic BPH but were not taking AAs (group 2). Comorbid conditions that might influence treatment results were considered, as were sizes of resection and pathologic results. RESULTS: No differences occurred between groups 1 (n = 38) and 2 (n = 25) in age, length of postoperative follow-up, or resection size. However, outcomes were poorer in group 1 than in group 2. A trend toward greater comorbidity that might lead to voiding dysfunction, though not statistically significant, was seen in group 1. CONCLUSIONS: Postoperative results of TURP may be less successful after AA therapy failure. This may be due to preoperative risk factors that affect voiding function rather than to prostatic size.

Adrenergic alpha-Antagonists↗
PubMed1999

Identification of a new recipient in the Sydney Blood Bank Cohort: a long-term HIV type 1-infected seroindeterminate individual.

We have reported previously a cohort of long-term survivors of HIV-1 infection, known as the Sydney Blood Bank Cohort, who received HIV-1-positive blood from a common infected donor. A new recipient, C135, has been identified. This recipient became infected after receiving blood donated during the presumed time of seroconversion of the donor in February 1981. C135 has been infected for more than 18 years without signs of disease progression. The virus load in this recipient has remained below the detectable level (<20 RNA copies/ml of plasma) and repeated Western blot analyses have given an indeterminate result. By booster PCR techniques we have demonstrated that this individual is infected with HIV-1 and have characterized the viral nef and nef/LTR region sequences present. The strain of HIV-1 identified contains deletions of 88 bp from the nef alone region and a total of 139 bp deleted from the nef/LTR overlap and LTR regions. The LTR contains three wild-type Sp1 transcription factor-binding sites, the 3' wildtype NF-kappaB site, and a duplicated Sp1 and NF-kappaB region. A truncated Nef protein of only 19 amino acids is encoded. The deletions and rearrangements in the nef gene and LTR sequences are characteristic of Sydney Blood Bank Cohort strains of virus. The identification of C135 increases the Sydney Blood Bank Cohort size to nine individuals and represents a rare example of a genuine, long-term HIV-1 infection accompanied by indeterminate anti-HIV-1 serology.

Amino Acid Sequence↗
PubMed1999

In rats, odor-induced Fos in the olfactory pathways depends on the phase of the circadian clock.

We used immunostaining for Fos to study the effect of circadian clock phase on odor-induced neuronal activation in the olfactory system in rats. Brief presentation of cedar odor to rats housed in constant darkness stimulated Fos expression in the main olfactory bulb, anterior olfactory nucleus, piriform cortex, and several other odor-responsive structures, both in the subjective day and subjective night phases of the cycle. Fos expression in response to odor, but not basal expression, was greatly enhanced in the subjective night in all structures examined. These findings are consistent with the idea that odor-induced neuronal activation in the olfactory pathways is modulated by the phase of the circadian clock.

Animals↗
PubMed1999

Rapid radiation events in the family Ursidae indicated by likelihood phylogenetic estimation from multiple fragments of mtDNA.

The bear family (Ursidae) presents a number of phylogenetic ambiguities as the evolutionary relationships of the six youngest members (ursine bears) are largely unresolved. Recent mitochondrial DNA analyses have produced conflicting results with respect to the phylogeny of ursine bears. In an attempt to resolve these issues, we obtained 1916 nucleotides of mitochondrial DNA sequence data from six gene segments for all eight bear species and conducted maximum likelihood and maximum parsimony analyses on all fragments separately and combined. All six single-region gene trees gave different phylogenetic estimates; however, only for control region data was this significantly incongruent with the results from the combined data. The optimal phylogeny for the combined data set suggests that the giant panda is most basal followed by the spectacled bear. The sloth bear is the basal ursine bear, and there is weak support for a sister taxon relationship of the American and Asiatic black bears. The sun bear is sister taxon to the youngest clade containing brown bears and polar bears. Statistical analyses of alternate hypotheses revealed a lack of strong support for many of the relationships. We suggest that the difficulties surrounding the resolution of the evolutionary relationships of the Ursidae are linked to the existence of sequential rapid radiation events in bear evolution. Thus, unresolved branching orders during these time periods may represent an accurate representation of the evolutionary history of bear species.

Animals↗
PubMed1999

Alpha-adrenoceptor antagonists in neurogenic lower urinary tract dysfunction.

Lower urinary tract dysfunction is common in patients with a variety of neurological diseases, and may lead to debilitating symptoms and serious complications. Any treatment that can reduce these symptoms or complications is welcome. In many trials, alpha-adrenoceptor antagonists (alpha blockers) have been evaluated as treatment for neurogenic lower urinary tract dysfunction; however, these have generally been small and often nonrandomized, uncontrolled studies. Existing evidence suggests that alpha blockers may have a small but useful effect in the facilitation of storage and emptying, and in the prevention of autonomic dysreflexia. Better understanding of lower urinary tract physiology and larger clinical trials with longer follow-up will hopefully clarify the role of alpha blockers in the future.

Adrenergic alpha-Antagonists↗
PubMed1999

Olfactory stimulation enhances light-induced phase shifts in free-running activity rhythms and Fos expression in the suprachiasmatic nucleus.

There is evidence to suggest that the olfactory and circadian systems are linked, functionally, and that olfactory stimuli can modulate circadian rhythms in mammals. Furthermore, olfactory bulb removal can alter free-running rhythms in animals housed in constant darkness and can attenuate the effect of social stimuli on photic entrainment of circadian rhythms. The mechanisms through which olfactory stimuli influence circadian rhythms are not known. One possibility is that olfactory stimuli influence circadian rhythms by modulating the activity of the circadian clock located in the hypothalamic suprachiasmatic nucleus. To study this, we assessed the effect of olfactory stimulation on free-running rhythms and on photic resetting of the circadian clock in rats using phase shifts in wheel-running rhythms and expression of the transcription factor Fos in the suprachiasmatic nucleus. We found that brief exposure to an olfactory stimulus, cedar wood essence, in the subjective day or subjective night had no effect on either free-running rhythms or Fos expression in the suprachiasmatic nucleus, but that when presented in combination with light, the odor dramatically enhanced light-induced phase shifts and Fos expression in the suprachiasmatic nucleus. Olfactory stimulation alone induced Fos expression in several structures that innervate the suprachiasmatic nucleus, pointing to ways by which stimulus information transmitted in the olfactory pathways could gain access to the suprachiasmatic nucleus to modulate photic resetting. These findings, showing that clock resetting by light can be facilitated by olfactory stimulation, point to a mechanism by which olfactory cues can modulate entrainment of circadian rhythms.

Animals↗
PubMed1999

A comparison of the angiotensin II antagonists valsartan and losartan in the treatment of essential hypertension.

We compared the angiotensin II receptor antagonist valsartan to losartan as an antihypertensive agent in an 8-week trial. Adults with uncomplicated essential hypertension (baseline seated diastolic blood pressure < 115 mm Hg and > or = 95 mm Hg) were randomized to receive 80 mg valsartan, 50 mg losartan, or placebo once daily. After 4 weeks doses of active medication and placebo were doubled. Seated systolic and diastolic blood pressures were measured and the response rate evaluated. Tolerability was assessed by the incidence of adverse events. Both angiotensin II receptor antagonists produced similar significant reductions in mean blood pressures at 4 and 8 weeks compared to placebo. Valsartan produced a significantly higher number of responders (62%) than losartan (55%, P = .02) at the 8 week treatment endpoint. The incidence of adverse experiences (AE) was similar in all three groups, with headache and dizziness reported most often. Valsartan (80/160 mg) monotherapy in this trial was as effective and well tolerated as 50/100 mg losartan in treating mild to moderate essential hypertension, and at 160 mg has a significantly higher responder rate than 100 mg losartan.

Adolescent↗
PubMed1999

The overactive bladder: neuropharmacological basis of clinical management.

The overactive bladder continues to pose a major challenge to clinicians treating lower urinary tract disorders, not least because our understanding of the pathogenesis of detrusor overactivity is still relatively limited. However, progress in understanding the basis of the overactive bladder is moving steadily forward, accompanied by a growing number of different forms of treatment. New pharmacological treatments and variations in the mode of delivery of older agents offer hope of efficacy with fewer side-effects. Neuromodulation is also offering a viable alternative to surgery in patients unresponsive to medical treatment.

Female↗
PubMed1999

Spinal cord injury research: review and synthesis.

This article provides a substantive review and synthesis of major areas of emphasis in spinal cord injury (SCI) research. Comprehensive examination of the current status and future implications for SCI research includes consideration of investigations from the following arenas: epidemiology, functional classification and prediction, neurophysiologic testing, models of injury and recovery, psychosocial considerations, surgical strategies, animal laboratory research, economic implications, life expectancy, complication rates, gender differences, pharmacological management, and prevention. Synthesis of these research conclusions from a broad spectrum of laboratory, clinical, and scientific domains provides opportunity for improving SCI prevention, treatment, and adaptation.

Animals↗