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Biomedical subjects

R Barrett

Publications and source records attributed to R Barrett.

At least 55 records · Page 3Linked to original sources
PubMed1990

B cell small lymphocytic lymphoma and chronic lymphocytic leukemia with peripheral neuropathy: two cases with neuropathological findings and lymphocyte marker analysis.

Two patients with lymphoproliferative disorders developed peripheral neuropathy and neoplastic lymphocytic nerve infiltrates. One of these patients, with B cell small lymphocytic lymphoma, presented with a chronic axonal neuropathy. CD22+, CD5- cells were identified in the epineurium. The other patient with chronic lymphocytic leukemia of 3 years duration developed a mixed axonal and demyelinating neuropathy. CD22+ and CD5+ cells were observed in the endoneurium. While the cause of the neuropathy in these two cases is unknown, intraneural or systemic autoantibody production may have led to the development of disease.

Aged↗
PubMed1990

Recent time trends in uterine cancer.

Recent trends in corpus uterine cancer incidence rates were explored using 1979-86 data from the Surveillance and End Results Program (SEER); recent trends in hospitalizations for corpus uterine cancer were explored using 1979-86 data from National Hospital Discharge Surveys (NHDS); and recent trends in exogenous hormone use were delineated using data from the 1980, 1981, and 1985 National Ambulatory Medical Care Surveys (NAMCS). Uterine cancer incidence rates using SEER data have continued to decline since 1979. An acceleration in the decline since 1983-84 is suggested in all women and in women with intact uteri ages 45-64. Hospitalizations for uterine cancer have also declined since 1979, with a marked acceleration in the decline since 1983-84 for all women and for women ages 40-79 has increased 22 percent and use of unopposed exogenous estrogens in women of similar age has increased 7 percent, while use of exogenous progesterones have shown much more substantial increases of approximately 700 percent. Possible relationships between trends in exogenous hormone use and incidence rates of corpus uterine cancer are discussed.

Adult↗
PubMed1990

Aging alters the phagocytic capability of inflammatory cells induced into cornea.

The changes in mouse corneal inflammatory cell population and the phagocytic capability of these cells were studied quantitatively at 24 and 48 hours after eliciting inflammatory cells into the cornea by Pseudomonas aeruginosa inoculation. Mice were selected for study according to their ability (young adult Swiss-Webster) or inability (aged Swiss-Webster) to restore corneal clarity after bacterial inoculation. Inflammatory cells were recovered from enzymatically disaggregated corneas, nucleated cells counted, and cell viability assessed to be 95% by trypan blue dye exclusion. Polymorphonuclear neutrophilic leukocytes (PMN) and macrophages recovered in this manner showed no significant differences in cell population contribution to the differential leukocyte count, but did show significantly fewer phagocytically active cells in aged when compared with young adult mice. These phagocytosis data were confirmed in a separate study using peripheral blood cells obtained from uninoculated mice of each age. The impaired phagocytic function seen in aged mice may contribute to the failure to resolve corneal clarity observed in these animals after Pseudomonas infection.

Aging↗
PubMed1990

Factors influencing the potential establishment of the winter tick (Dermacentor albipictus) in Alaska.

The winter tick (Dermacentor albipictus) is not known to occur in Alaska. Survival and development of free-living (i.e., non-host-associated) stages of the tick were studied at three sites in central and southern Alaska. Female ticks survived, oviposited, and eggs hatched at all sites. Hatch success was low at one site where summer temperatures were low. Results suggest that establishment of winter ticks in Alaska following accidental translocation is possible, but several factors would affect such establishment.

Alaska↗
PubMed1989

Effect of the hemopump left ventricular assist device on regional myocardial perfusion and function. Reduction of ischemia during coronary occlusion.

The Hemopump is a new 7-mm diameter left ventricular assist device that provides as much as 3.5 l/min of nonpulsatile cardiac output after fluoroscopic placement into the left ventricle through a femoral artery cutdown. The purpose of this study was to measure the effects of Hemopump assist on hemodynamics, left ventricular function, and perfusion in the presence and absence of ischemia. Eight dogs were instrumented under pentobarbital anesthesia with left ventricular, left atrial, and aortic catheters, a loose silk ligature around the midleft anterior descending coronary artery, and sonomicrometer crystals in midwall myocardium within the left anterior descending and circumflex perfusion territories. Hemodynamic variables, regional systolic fractional shortening, and myocardial perfusion after left atrial injection of 15-microns radiolabeled microspheres were measured in the presence and absence of Hemopump assist before and after left anterior descending artery occlusion. In the absence of ischemia, Hemopump left ventricular assist resulted in reduced left ventricular end-diastolic pressure while aortic mean pressure was maintained, and there was significant reduction in regional systolic fractional shortening (reflecting systolic unloading) that correlated with an 18% decline in regional myocardial perfusion. During left anterior descending artery occlusion, left ventricular systolic and diastolic pressures were reduced during Hemopump assist while aortic mean pressure was maintained. Perfusion rose in the ischemic territory (from 13.0 +/- 8.7% to 26.2 +/- 19.8% of nonischemic flow, p = 0.045). Reduced fractional shortening was again seen in nonischemic tissue with Hemopump assist during left anterior descending artery occlusion, and this was often correlated with reduced perfusion (r = 0.67).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Changes in center of gravity in boys with Duchenne muscular dystrophy.

A study was undertaken, using methods of stabilometry to compare stability of stance in normal children (n = 37) and those with Duchenne muscular dystrophy (n = 61). The purpose of this study was to monitor changes in the locus of the center of gravity and the range and frequency of sway and to evaluate the effect of orthotic application in an attempt to obtain information that would assist further development of orthoses. In group 1, boys with Duchenne muscular dystrophy who were still walking without assistance (mean age 7.2 +/- 1.76 years), the analysis of sway showed that, between 5 and 6 years of age, the boys already had ranges of anteroposterior (A/P) and lateral (Lat) sway that were significantly greater than those found in normal children (A/P P less than 0.05, Lat P less than 0.01). In group 2, boys with Duchenne muscular dystrophy when orthoses had been introduced (n = 23, mean age 10.4 +/- 1.47 years), the center of gravity was returned to a more normal position. There was a reduction of the anteroposterior range of sway, but the lateral range of sway remained significantly greater (P less than 0.01) as did the frequency of sway in both the anteroposterior and lateral directions (A/P P less than 0.001, Lat P less than 0.001).

Child↗
PubMed1988

Monoclonal antibodies provide protection against ocular Pseudomonas aeruginosa infection.

A panel of well characterized monoclonal antibodies (MAbs) directed against outer membrane proteins H2, or F (porin) of Pseudomonas aeruginosa were examined to determine whether they exhibited any protective effect against subsequent ocular challenge with the bacteria topically applied to the scarified corneal surface. Mice were observed macroscopically following bacterial challenge and the degree of ocular disease graded on a scale of 0 to 4 (0, normal, fully protected cornea; 4, corneal perforation or phthisis, not protected). Mice treated intravenously with either MAb MA1-6 (anti-H2) or MA2-10 (anti-F), or a combination of these two MAbs and MAb MA4-4 (anti-F), two hours before corneal challenge with the viable bacteria, exhibited significantly less corneal disease than mice either not treated with the MAbs, treated with MA4-4 alone or treated with MAb MA1-3 (anti-I). The latter MAb is directed against an outer membrane epitope that is not surface exposed. Light and transmission electron microscopic histopathology also was employed and provided confirmatory evidence to support the macroscopic analyses.

Animals↗
PubMed1987

Sodium hyaluronate eye drop. A scanning and transmission electron microscopy study of the corneal surface.

The association with time (0-60 min) of an eye drop preparation containing sodium hyaluronate with the corneal epithelial cell surface was examined using both cryofixation and osmium tetroxide vapor fixation and scanning (SEM) and transmission electron microscopy (TEM). In phosphate-buffered saline (PBS)-treated control eyes of adult mice, 37 postnatal days (PND) old, a variably thick, but well-defined preocular mucus coat was seen, while 5-PND-old animals treated with PBS lacked morphologically detectable mucus at the corneal surface. In mice of both ages, the eye drop preparation was detectable at the corneal surface at time 0 and 5, 15, 30 and 60 min after its application. For these time periods, in both the adult and the pup, the eye drop preparation containing sodium hyaluronate appeared to be composed of electron-dense filamentous material (TEM) which associated with corneal surface cell microvilli. SEM revealed that the eye drop preparation was globular in composition and that its distribution became patchy over the cornea with time for both the adult and the pup.

Animals↗
PubMed1984

The influence of sampling site upon the distribution phase kinetics of thiopentone.

In six sheep anaesthetised with ketamine blood was sampled from the jugular and femoral veins and the femoral artery at frequent intervals for 12 minutes following the intravenous administration of 5 or 10 mg/kg sodium thiopentone. Samples were also taken from cubital veins and radial arteries of five patients who received 5 mg/kg thiopentone. The plasma concentration of thiopentone was determined by an HPLC assay. The time course of plasma concentration of thiopentone showed considerable variation according to sampling site as well as variation between individuals. Such sampling site-dependent variation may result in the appearance of acute tolerance.

Animals↗
PubMed1978

Performance of institutional retardates on standard and new forms of the Quick Test.

121 institutionalized mentally retarded patients were tested on Forms 1-3 and 4-6 of the Quick Test; IQs were correlated with other IQs available from institution records. The forms of the Quick Test correlated significantly with the more traditional and time-consuming tests of intellectual performance. It was concluded that the Quick Test is an excellent tool for experimenters and educators who need an efficient and reliable estimate of intellectual development.

Adolescent↗