Biomedical subjects
J Cook
Publications and source records attributed to J Cook.
Extracorporeal membrane oxygenation for newborn infants with persistent pulmonary hypertension.
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Use of a tunneling device to aid in positioning of a graft.
A tunneling device can be used to ensure easy placement of a prosthetic or autogenous graft. This can be done without the danger of the graft twisting, kinking or having the clips and ties pulled off. The often frustrating problem of ensuring that the arterial graft lies properly in position can be greatly simplified with the use of this technique.
Clinical illness associated with a commercial tick and flea product in dogs and cats.
A commercial flea and tick product containing 9.0% fenvalerate for use in dogs and cats was suspected of causing illness. An acute toxicity study was performed in 10 dogs and 10 cats exposed to the product orally (po) and dermally at differing doses. Samples were obtained for DEET and fenvalerate analysis. Oral dosing of dogs and cats produced severe clinical illness at doses as low as 0.66% of a can (7 ounce spray can)/kg body weight. Dermal application of the product resulted in minor clinical abnormalities in dogs. Oral exposure at 0.5% can/kg body weight resulted in severe illness, and dermal application caused severe illness or death in cats at 20% and 40% of a can/kg body weight. The cats receiving 10% of a can/kg body weight dermally became depressed for several hours but recovered uneventfully. Serum DEET concentrations closely paralleled the clinical signs observed in the animals. Serum concentrations of DEET above 20 ppm were considered diagnostic for intoxication. Urine concentrations of DEET above 1 ppm and tissue (liver, bile, and kidney) concentrations of DEET above 10 ppm were supportive of poisoning; values near 100 ppm were diagnostic for fatal poisoning.
Detection of protein-DNA complex formation by time-resolved fluorescence depolarization of bound ethidium bromide.
We introduce the use of time-resolved fluorescence spectroscopy to probe the interaction between gene regulatory proteins and DNA. Changes in the decay kinetics of fluorescence polarization anisotropy of ethidium bromide bound to DNA segments report changes in hydrodynamic volume and shape which occurs upon complex formation between protein and DNA. We have used the decay of fluorescence polarization anisotropy as a spectroscopic handle on the interaction between several site-specific DNA-binding proteins involved in transcriptional regulation (the cro repressor of coliphage lambda, the lac repressor of Escherichia coli, and the RNA polymerase of coliphage T7) and their target DNA fragments ranging in length from 17 to 36 base pairs. The technique allows one to follow complex formation while varying solution conditions such as temperature, pH, ionic strength, and presence of effector molecules. Macromolecular concentrations ranging from 10(-7) to 10(-4) M can be used, allowing estimates of relative binding affinities. The magnitude of the observed rotational correlation times (phi obs) can be used to infer information about the size and shape of the complexes.
Molecular basis of the variation exhibited by avian infectious bronchitis coronavirus (IBV).
IBV serotype-specific, virus neutralising (VN) antibody is induced by the S1 subunit of the spike (S) glycoprotein. A Portuguese isolate (Port/322/85) is considered to be an in vivo recombinant. VN tests showed that it belongs to the Massachussetts (Mass) serotype. Correspondingly, the sequence of S1 and S2 was extremely similar to that of older Mass isolates. However, the matrix (M) glycoprotein and upstream gene sequences were atypical of these Mass strains and more closely resembled other serotypes isolated in Europe. The recombination event had occurred within the sequence between the M and S genes (corresponding to mRNA 3) or near the 3' terminus of the S2 gene.
Investigations into resistance of chicken lines to infection with infectious bronchitis virus.
Although nine inbred and partially inbred lines of chickens were equally susceptible initially to infection with infectious bronchitis virus (IBV), the outcome of that infection varied considerably between the lines. A more detailed study of a line which was resistant (line C) and one which was highly susceptible (line 15I) confirmed that both lines could be infected initially with IBV but showed that the respiratory tract epithelium of line C chicks recovered more rapidly than that of line 15I chicks. Whereas more virus could be recovered from tissues of line 15I chicks following IBV inoculation, explants of tissues from each line inoculated in vitro appeared equally susceptible. The possibility of a different immunological response to IBV infection in the two lines is discussed and it is clear that further work is required to elucidate the mechanism involved in the differing susceptibility of the inbred chicken lines to inoculation with IBV.
Amino acid sequences of ovomucoid third domain from 25 additional species of birds.
Ovomucoids were isolated from 25 avian species other than the 101 studied in Laskowski et al. (1987, Biochemistry 26, 202-221). These were subjected to limited proteolysis with an appropriate enzyme, and connecting peptide extended ovomucoid third domains were isolated and sequenced to the end in a protein sequencer. Of the 25 new sequences, 13 duplicate ones were already known, and 12 are unique. Probably the most striking findings are a Pro14----Ser14 replacement in weka, an Ala14----Thr15 replacement in Bulwer's pheasant, the discovery of two additional amino acid residues Ile18 and Gly18 at the P1 reactive site position in Kalij pheasant and tawny frogmouth, respectively, and the first finding of a negative (Glu34) rather than positive (Lys34 or Arg34) amino acid residue at the NH2 terminus of the alpha helix in caracara ovomucoid third domain. These results complete the determination of all the sequences of ovomucoid third domains in the four species genus Gallus, in the five species genus Syrmaticus, and in the two species genera Aix and Pavo.
Angiotensin converting enzyme inhibitor therapy to decrease microalbuminuria in normotensive children with insulin-dependent diabetes mellitus.
It has been proposed that lowering glomerular pressure in children with insulin-dependent diabetes mellitus will reduce microalbuminuria and that this reduction may preserve renal function. We therefore conducted a double-blind, placebo-controlled, crossover trial to compare 3 months of treatment with the angiotensin converting enzyme inhibitor captopril (0.9 mg/kg/day), and 3 months of placebo administration to 12 normotensive adolescents with insulin-dependent diabetes mellitus, 11 with microalbuminuria (albumin excretion rate of 15 to 200 micrograms/min) and one with early overt nephropathy. Mean age (+/- SD) was 14.4 +/- 1.7 years, and disease duration was 5.1 +/- 2.5 years. Albumin excretion rate decreased significantly during captopril therapy (baseline 78 +/- 114 micrograms/min; mean of monthly measurements 38 +/- 55 micrograms/min vs placebo 78 +/- 140 micrograms/min; p less than 0.001). During captopril therapy, albumin excretion was reduced by 41 +/- 44% and decreased in 10 of 12 subjects, but was unchanged in two, one with a borderline albumin excretion rate (16.3 micrograms/min) and one with diabetes of short duration (2.9 years). Plasma renin activity rose significantly during captopril therapy, and mean arterial pressure decreased slightly (placebo 81 +/- 7 mm Hg; captopril 76 +/- 5 mm Hg; p = 0.004). After 3 months of captopril treatment, glomerular filtration rate and renal plasma flow did not change significantly. Hemoglobin Alc values remained stable during the study. The only side effect of captopril was diarrhea in one patient. We conclude that, in the short term, captopril is effective in decreasing albumin excretion rate in normotensive children with insulin-dependent diabetes mellitus and microalbuminuria, without significant side effects. Longer trials are indicated in an attempt to delay or prevent overt nephropathy.
The effects of topical fluticasone propionate on allergen-induced immediate nasal airways response and eosinophil activation: preliminary results.
Nasal application of grass pollen allergen in atopic individuals with seasonal rhinitis leads to an early rise in nasal airways resistance. The effects of fluticasone propionate, a powerful, topically active glucocorticosteroid, on nasal airways resistance and cellular infiltration of the nasal mucous membrane were investigated. Fluticasone propionate blunted the rise in nasal airway resistance following allergen challenge (P = 0.089). Although this glucocorticosteroid did not affect the total number of eosinophils in biopsies of nasal mucous membrane, the number of activated eosinophils was significantly reduced (P less than 0.05).
Overnight versus 24-h urine collection in detection of microalbuminuria.
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The hand apraxia scale.
A scale for the assessment of hand apraxia was developed on a population of 239 institutionalized mentally retarded adults. Guttman scaling indicates adequate reliability and validity.
Preliminary report on construction and validation of a pediatric sleep disturbance questionnaire.
A scale to assess sleep disturbance of children with developmental disabilities is reported. The scale has been used with a small sample of 14 children diagnosed as having Tourette Disorder, 36 physically handicapped children (cerebral palsy). Also, a group of 115 nonhandicapped Native American children were surveyed to assess whether the items might be appropriate for use with such children. The scale has 6 distinct factors and appears to have adequate reliability and validity.
Sex differences in the functional asymmetry for facial affect perception.
Twenty-six right-hand-dominant women and 26 right-hand-dominant men were required to identify the facial affective expression of Ekman and Friesen's (1978) angry, happy, and neutral stimuli using a forced-choice reaction-time paradigm with only angry or happy alternatives signified by the respective response manipulanda. Stimuli were presented within the left or right visual fields to provide additional data on sex differences in the lateralized processing of facial affective stimuli. The results supported the hypothesis of greater laterality among men with equivalent response times for women and men to stimuli within the right but not the left visual fields. Men were significantly faster in processing affective facial information within the left visual field. The results also indicated that differential rates of learning occur in affective tachistoscope tasks for happy and angry stimuli. Thus, opposite conclusions may be derived from procedural differences among studies in the number of identification trials employed.
In vitro photodynamic therapy of human lung cancer: investigation of dose-rate effects.
The influence of light dose-rate delivery was studied in human lung adenocarcinoma A549 cells treated with hematoporphyrin derivative (Photofrin II)-based photodynamic therapy. Clonogenic cell survival curves were generated for cells treated for 2 h with 25 micrograms/ml of Photofrin II followed by exposure to light delivered at 0.3, 0.15, 0.075, or 0.0375 milliwatts/cm2. Cellular sensitizer levels, as determined by fluorescence measurements, remained constant over the entire time course of all light exposures. As the dose rate of light delivery was decreased, a significant increase in cell survival was observed at equal light energies (225 mJ/cm2). The enhancement in survival from the highest to the lowest dose rate used was 1.6-fold (at the 50% survival level). These findings may have important clinical implications relating to photodynamic therapy of tumors and may provide a partial explanation for treatment failure.
Passive transfer of HIV antibody by hepatitis B immune globulin.
Two newborns of mothers carrying hepatitis B and at high risk for human immunodeficiency virus (HIV) infection developed HIV-positive test results by enzyme-linked immunosorbent assay and Western blot tests after birth. Both had been administered hepatitis B immune globulin within 48 hours of birth. Serological tests detected HIV antibody as long as 17 days after birth. Both newborns had received lots of hepatitis B immune globulin containing antibody to HIV. While hepatitis B immune globulin cannot transmit HIV infection to recipients, physicians should be aware that administration of older lots of this preparation may result in transiently positive tests for HIV antibody in the recipients. Lots manufactured from screened plasma do not contain antibody to HIV.
Reminiscence groups with confused nursing center residents: an experimental study.
Reminiscence groups have been used successfully in several types of elder-care settings. This article is a study of the use of reminiscence groups with confused elderly residents of nursing centers in an attempt to improve the quality of subjects' social behaviors. Results partially supported the hypotheses. Social and demographic data were correlated with improvement or lack of it. The study suggests that the skills of the therapist are an important variable in reminiscence therapy as is true with other types of professional intervention.
Aspiration of middle ear effusions prior to grommet insertion an etiological factor in tympanosclerosis.
Fifty-five children with bilateral middle ear effusions were entered into a prospective randomized double blind trial to determine whether aspiration of middle ear effusions prior to ventilation tube insertion influences ventilation tube extrusion time or the development of tympanosclerosis. Following myringotomy, aspiration of the left or right ear only was performed randomly prior to ventilation tube insertion. The tympanic membranes were inspected six-monthly to determine whether ventilation tube extrusion had occurred, and at 24 months after surgery for the presence of tympanosclerosis. Results showed no significant difference in extrusion time between aspirated and non-aspirated ears. Aspiration was found to be a factor in the development of tympanosclerosis. We conclude that routine aspiration of the middle ear effusion prior to ventilation tube insertion is associated with an increased risk of tympanosclerosis.