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Biomedical subjects

J Hawkins

Publications and source records attributed to J Hawkins.

At least 55 records · Page 3Linked to original sources
PubMed1991

Structural elements in the N-terminal half of transcription factor IIIA required for factor binding to the 5S RNA gene internal control region.

Zinc binding domains and the conserved Thr-Gly-Glu-Lys (TGEK) tetrapeptide in the N-terminal half of transcription factor IIIA (TFIIIA) were subjected to in vitro mutagenesis to biochemically assess their role in factor interaction with the 5S gene internal control region (ICR). TFIIIA containing a Leu in place of His33 in the Cys2His2 zinc binding site of finger I lost the ability to protect the entire 5S RNA gene ICR (nucleotides +96 to +43) from DNase I digestion. Thus, mutation of one potential zinc ligand in the N-terminal finger inhibited specific DNA binding by the N-terminal as well as downstream fingers. Cooperativity apparently exists among TFIIIA zinc fingers in metal binding/finger folding and DNA binding. Substituting a Ser for Gly69 or a Glu for Lys 71 in the conserved TGEK tetrapeptide in finger II of TFIIIA resulted in the loss of DNA binding. A Gly-dependent bend structure and a terminal positive charge in this tetrapeptide are important for TFIIIA interaction with DNA. Whereas TFIIIA with a Ser substituted for Cys20 in finger I (proposed zinc ligand) did not protect the ICR from DNase I digestion, TFIIIA containing a Ser substituted for Cys35 (not a proposed zinc ligand) retained the ability to bind the ICR. When Cys112 or Cys 164 (proposed zinc ligands in fingers IV and VI) were replaced by Ser, the DNase I footprint patterns afforded by the respective mutant proteins were similar, protection on the ICR from about nucleotides +96 up to +78. A similar pattern was obtained with a TFIIIA mutant in which fingers V, VI, VII, and a portion of VIII were deleted. Maintenance of zinc coordination spheres in necessary for DNA binding by downstream fingers. The six fingers comprising the N-terminal half of TFIIIA appear to act in two groups of three with binding of the second group dependent upon initial binding of the N-terminal group to the +90 to +80 region of the 5S gene ICR.

Amino Acid Sequence↗
PubMed1991

Fourth report of the cooperative, open-ended study of slowly growing mycobacteria by the International Working Group on Mycobacterial Taxonomy.

The open-ended study of the International Working Group on Mycobacterial Taxonomy is an ongoing project to characterize slowly growing strains of mycobacteria that do not belong to well-established or thoroughly characterized species. In this fourth report we describe two numerical taxonomic clusters that represent subspecies or biovars of Mycobacterium simiae, one cluster that encompasses the erstwhile type strain of the presently invalid species "Mycobacterium paraffinicum," one cluster that is phenotypically very similar to Mycobacterium avium and Mycobacterium intracellulare but may be a separate genospecies, one cluster that appears to be phenotypically distinct from M. avium but reacts with a nucleic acid probe specific for M. avium, and three tentatively defined clusters in proximity to a cluster that encompasses the type strain of Mycobacterium malmoense. Of special practical interest is the fact that one of the latter three clusters is composed of clinically significant scotochromogenic bacteria that can be misidentified as the nonpathogenic organism Mycobacterium gordonae if insufficient biochemical tests are performed.

Agglutination Tests↗
PubMed1991

Administrators should help restore the image of physicians.

Physicians are being knocked from the proverbial pedestal by every conceivable player involved in health care: the consumer, the federal government, the payer. How can hospitals, specifically administrators, aid in revamping the image? In the following article, the author proposes several steps to help physicians recover their image--and perhaps build loyalty to the institution in the process.

Hospital Administrators↗
PubMed1989

Effects of increasing afterload on left ventricular output in fetal lambs.

Fetal ventricular performance has been considered limited because ventricular output does not increase with rapid volume expansion above mean left atrial pressures (mLAPs) of 5-7 mm Hg. To explore relations between preload, afterload, and stroke volume (SV) in the fetal left ventricle, we instrumented 126-129 days gestation fetal lambs with ascending aortic electromagnetic flow transducers, vascular catheters, and inflatable occluders around the aortic isthmus (n = 8) or descending aorta (n = 7). At 24-48 hours after surgery, blood was withdrawn or infused to reach various mLAPs. The aorta was then slowly occluded as aortic flow and mean arterial pressure (MAP) were measured continuously. Isthmus constriction produced linear decreases in SV as MAP increased; mLAP was unchanged. Descending aortic constriction produced no decrease in SV until high MAPs were reached. SV decreased as MAP increased further, and mLAP rose significantly. The curve relating mLAP and SV before constriction showed little increase in SV above mLAPs of 5-7 mm Hg; however, when curves were derived relating SV and mLAP at relatively constant MAPs, SV continued to increase even above an mLAP of 8-10 mm Hg. Our studies indicate that the fetal left ventricle responds to progressive increases in mLAP to at least 10 mm Hg. The lack of increase in SV above an mLAP of 5-7 mm Hg with rapid volume expansion is related to the concomitant increase in MAP and afterload.

Animals↗
PubMed1989

Sleep disturbance in intentional self-awakenings: behavior-genetic and transient factors.

Unaided self-awakenings were studied, using a baseline vs treatment comparison with 84 undergraduate subjects serving as their own controls. The data suggest that situational constraints related to time and sleep environment affect successful awakenings, that the subjects' instructional set produces a temporary sleep disturbance, and that chronically sleep satisfied or dissatisfied groups respond differently to the procedures used here.

Adult↗
PubMed1988

A study of childhood scalds.

A retrospective review of admissions to the Wessex Regional Burn Centre was made to determine the incidence and causes of childhood scalds during the periods 1960-65 and 1979-84. No reduction in numbers injured or significant change in causes were observed. Children aged 1-2 years old are still the most prone to scalding injury.

Accidents, Home↗
PubMed1987

Rat strain comparisons on drug and sleep sensitive behaviors.

Rat swimming behaviors have been productive in both sleep research and neuropharmacology. In this report, both of these areas are addressed in the context of inbred strain effects. Thirty-two rats from three stocks were tested in a seven day, repeated measures design. Each rat swam for 5 min each day in shallow 25 degrees C water. There were significant differences between inbred stocks on two measures which can be related to both REM sleep deprivation and adrenergic drug effects. Nonsignificant strain differences were found on two other behaviors which also lack significance under REM sleep deprivation and atropine sulfate treatments. It is concluded that there may be differential stress affecting the treatment-sensitive and the change-resistant behaviors.

Animals↗
PubMed1987

Evolution of a nursing center.

The collaborative spirit that characterized the project period resulted in continuation of the nursing center after the expiration of the contract. The town purchased the modular unit and provides ongoing maintenance, housekeeping services, and utilities. A secretary is funded through a program providing employment for older adults. The University provides the salary for one full-time certified NP to manage the center, and students and faculty together provide care and continue the services of the center. An advisory committee composed of representatives from the town, senior center, and university oversees the ongoing activities of the center. Although the center has evolved from a small room to a fully equipped modular unit, the purpose of providing high-quality nursing care through education, practice, and research remains the same.

Aged↗
PubMed1987

Body composition and physiological characteristics of law enforcement officers.

The physical work capacity, body composition, and physiological characteristics of 12 law enforcement officers (9 males, 3 females) were measured. Subjects included a representative sample from the occupational categories of detective, staff, investigative and patrol officer. Mean maximal oxygen uptake of the men was 42.1 +/- 8.9 ml.kg-1min-1 with mean values of 41.5 +/- 8.7 ml.kg-1min-1 for the women. Measurement of body composition indicated an average of 24.4 +/- 7.1% body fat for the men and 30.9 +/- 1.2% for the women. Muscular power, strength, and endurance as measured by isolated limb flexion-extension movement and fitness test performance was considered average with no excessive bilateral differences. The results of this study were compared with other investigations of law enforcement officers of similar age groups. The officers displayed average or above health and physical fitness scores for their age classification and were able to complete all police task-oriented tests.

Adult↗
PubMed1987

Quadrantanopic field defect associated with intracranial calcification.

A homonymous quadrantanopic visual field defect was discovered in a healthy, asymptomatic 43-year-old female. Computerized tomography revealed the source of the field defect. Since visual field defects can be associated with life threatening disorders, eye examinations should include some assessment of the visual field.

Adult↗
PubMed1986

Inbreeding considerations in a REM sleep model for rat swimming activity.

Over the past few years, our laboratory group has elaborated a repeated measures rat swimming test. It provides an animal base for showing that the REM sleep mechanism is important to both emotional responsiveness and environmental adaptations. All of that work has been done with Sprague-Dawley rats obtained from a local supplier. Work done with two European rat stocks (by researchers in France and The Netherlands) shows general agreement with our own. In this presentation, we directly compare rats derived from an English vendor's Sprague-Dawley stock with the U.S. based Sprague-Dawley stock which we have been using. We also make strain comparisons via the F344 and the Long Evans strains. Although the literature has numerous examples of swimming test differences between inbred and wild rat stocks, strain difference effects have not been reported. We report that there are significant differences attributable to inbred strain but not to vendor on this measure.

Animals↗