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Biomedical subjects

B Young

Publications and source records attributed to B Young.

At least 235 records · Page 13Linked to original sources
PubMed1976

Constraints on classificatory skills in young children.

On three occasions over a one-year period 23 children aged 3-4 were asked to match target objects with other objects which were similar to the target in shape or in colour but not in both. A sequence of matches to each target was asked for. The structure of these sequences is examined for evidence of classifacatory abilities. Many subjects appear to be attempting (not always successfully) to follow a strategy of 'holding fast' to their original choice of matching criterion (colour or shape) on subsequent trials. The striking differences between performance after a first-trial colour-match and after a first-trial shape-match are described. It is argued that development during this period involves an increasing ability to ignore the more salient attribute (shape) when matching by colour. The general developmental significance is discussed.

Aptitude↗
PubMed1976

Maintenance of therapeutic phenytoin plasma levels via intramuscular administration.

A parenteral dosing regimen was designed for the immediate attainment and maintenance of therapeutic plasma levels of phenytoin in patients requiring anticonvulsant therapy, but not able to tolerate oral medication. An intravenous dose of 10.7 mg/kg body weight infused at a rate of 25 mg/min immediately followed by an intramuscular dose of 12.7 mg/kg body weight were administered initially. This was followed by daily intramuscular maintenance doses, generally 8.6 mg/kg body weight, until oral medication could be tolerated. Due to variability between subjects, primarily in metabolism, the predicted maintenance doses had to be adjusted in approximately one third of the patients. This regimen for the dosing of phenytoin was evaluated in 98 patients and consistently yielded therapeutic levels.

Administration, Oral↗
PubMed1975

Early post-traumatic epilepsy prophylaxis.

An anticonvulsant regimen is described using diphenylhydantoin specifically designed for use in the acutely head injured patient. Initial doses of diphenylhydantoin based on body weight and maintenance doses determined by plasma concentrations of the drug are utilized to provide immediate and maintainable anticonvulsant blood levels.

Craniocerebral Trauma↗
PubMed1973

Genetic determination of the constitutive biosynthesis of phospho- -glucosidase A in Escherichia coli K-12.

Escherichia coli wild-type cells form constitutively the enzyme phospho-beta-glucosidase A, which has a high affinity for phosphorylated aromatic beta-glucosides and a low affinity for phosphorylated beta-methyl-glucoside. Phospho-beta-glucosidase B and beta-glucoside permease I are formed in aromatic beta-glucoside-fermenting mutants. Mutants lacking phospho-beta-glucosidases A and B have been isolated. These mutants showed a reduced rate of inducibility of the beta-glucoside permease I. The restoration of phospho-beta-glucosidase A or B activity resulted in an increased rate of induction of the beta-glucoside permease I. The presence of the phospho-beta-glucosidases was not required for the constitutive biosynthesis of the beta-glucoside permease. Mutants selected for growth on beta-methyl-glucoside as carbon source showed an increased level of constitutive phospho-beta-glucosidase A activity. Gene bglD, the structural gene for phospho-beta-glucosidase A, was mapped between the pyrE locus and the cluster bgl loci, whereas bglE, the regulatory site determining the hyperproduction of phospho-beta-glucosidase A, was mapped between the bgl and ilv clusters. The bglE locus appears to have a regulatory effect on the expression of the bglD gene.

Carbon Isotopes↗
PubMedDate not supplied

Ceftazidime versus tobramycin/ticarcillin in treating hospital acquired pneumonia and bacteremia.

Thirty-five patients in a neurosurgical intensive care unit who had nosocomial pneumonia and bacteremia were randomly assigned to receive either ceftazidime (Cef) or the combination of ticarcillin and pharmacokinetically adjusted doses of tobramycin (T/T). Fifteen of 17 patients (88%) who received Cef were cured or improved compared to 15 of 18 (83%) who received T/T. The original pathogen was eradicated from the respiratory secretion in 10 of 15 patients receiving Cef compared to only 6 of 18 patients receiving T/T (p = 0.12). All patients in both treatment groups who had positive blood cultures cleared the organism from the bloodstream. No cases of drug toxicity, including renal toxicity, were seen in either group. Cef used as a single agent in nosocomial pneumonias and bacteremias performed at least as well as T/T.

Adult↗
PubMedDate not supplied

Automatic intracranial pressure regulation.

This paper emphasizes our approach to control increased ventricular fluid volume and pressure; it utilizes an improved device based upon hydrostatic pressure principles. Intracranial pressure may be maintained at any preselected value, usually 25 cm H2O. Pressure increases beyond this value will result in a venting of fluid into a calibrated reservoir. The hydrostatic column will act to cushion the surrounding ventricular mass, helping to prevent ventricular collapse. The method overcomes the hazards of techniques, using intermittent withdrawal of fluid which requires human judgment. Ventricular pressure response curves performed on a number of patients showed a marked stability with a response less than 2 mm Hg/ml. This indicates a favorable influence on the intracranial compliance. The system is completely closed and its use in 52 neurosurgical patients in over 400 patient days has not been associated with any infection problem.

Humans↗
PubMedDate not supplied

Cerebral vascular response to moderate blood loss: modification by hypertension.

To study the effect of non-hypotensive hemorrhage on cerebral blood flow in normo- and hypertensive states, chloralose anesthetized cats were subjected to graded blood loss (5 ml/kg) every 30 min. Cerebral blood flow was measured using radiolabelled microspheres or H2 clearance. Hypertension was produced by infusion of phenylephrine to a diastolic blood pressure of 100 mm Hg. Control animals suffered no net blood loss. PCO2 was between 28 and 32 mm Hg for all groups over the entire experiment. In normotensive cats, cerebral blood flow increased following withdrawal of 10 ml/kg of blood. In hypertensive cats, cerebral blood flow increased after withdrawal of 20 ml/kg of blood. These findings were consistent for all brain regions examined. Animals without blood loss, whether normo- or hypertensive showed no consistent change in cerebral blood flows. Possible explanations for these findings, particularly neurally mediated responses, are discussed.

Animals↗
PubMedDate not supplied

The metabolic response to brain injury.

Every year several million people sustain brain injury. The development of an optimal metabolic and nutritional support program for brain-injured patients relies on an understanding of the metabolic response and nutritional complications that occur with brain injury. Severely brain injured patients have increased serum and urine levels of norepinephrine, epinephrine, and cortisol. These patients also have increased oxygen consumption and urinary nitrogen excretion. This group has observed hypozincemia, hyperzincuria, increased serum C-reactive protein and copper concentrations, and hypoalbuminemia in nonsteroid-treated severely brain-injured patients. Experimental head injury produces interleukin-1 (IL-1) of brain origin. This cytokine mediates many of the aspects of the acute phase response, including all of the metabolic abnormalities reported by our group. IL-1, when administered intracerebroventricularly to experimental animals, appears to have enhanced biological activity compared to that administered systemically. Interleukin-1 activity has been found in significant amounts in the intraventricular fluid of head-injured patients. We suggest that IL-1 acts in concert with traditional stress hormones such as epinephrine, norepinephrine, and cortisol to produce the profound metabolic disturbances observed in the head-injured patient.

Acute-Phase Reaction↗
PubMedDate not supplied

Comparison of urinary urea nitrogen excretion and measured energy expenditure in spinal cord injury and nonsteroid-treated severe head trauma patients.

Severe head trauma patients (HT) exhibit markedly elevated energy expenditure and 24-hr urinary urea nitrogen excretion (UUN) values. The objective of this study was to compare seven spinal cord injured patients (SCI) to seven HT for changes in UUN and measured energy expenditure (MEE) over the first 18 days following injury. Energy expenditure was measured by indirect calorimetry and compared to values predicted by the Harris Benedict Equation (PEE). There were six quadriplegics and one paraplegic in the SCI group. HT patients had peak Glasgow Coma Scale scores of 3 to 10 for the first 24 hr postinjury. Patients were studied prospectively and matched for age, sex, and admitting weight Week 1 following the injury, SCI had mean UUN values of 0.18 +/- 0.04 g/kg/day vs 0.18 +/- 0.01 for HT patients. The mean MEE/PEE ratio was 0.56 for the SCI and 1.4 for HT (p less than 0.01). Over the entire study period the mean UUN value for SCI was 0.23 +/- 0.03 g/kg vs 0.21 +/- 0.01 for HT. The mean MEE/PEE ratio for SCI was 0.94 while HT remained elevated at 1.5 (p less than 0.05). Although the UUN was comparable in SCI vs HT, there was a significant difference in MEE/PEE between the groups. The elevation in UUN observed in SCI is not due to a hypermetabolic state. This suggests that different mechanisms promote the increased nitrogen excretion observed in these two populations.

Acute Disease↗