Biomedical subjects
L Donaldson
Publications and source records attributed to L Donaldson.
Purification and characterization of the carboxyl-terminal transactivation domain of Vmw65 from herpes simplex virus type 1.
A glutathione S-transferase fusion to the COOH-terminal acidic transactivation domain of Vmw65 from herpes simplex virus type 1 was overexpressed in Escherichia coli and isolated by affinity chromatography on glutathione-Sepharose. Following cleavage of the fusion protein with thrombin, the transactivation domain was purified to homogeneity by ion exchange chromatography yielding approximately 0.6 mg of protein/liter of bacterial culture. Equilibrium sedimentation analysis showed the purified polypeptide to be monomeric; however, it displayed aberrant electrophoretic and chromatographic properties. Contrary to secondary structure predictions, circular dichroism spectroscopy demonstrated that this transactivation domain was devoid of significant alpha-helical structure at physiological conditions. The polypeptide, however, became notably more structured under hydrophobic conditions or at low pH, suggesting that it was sensitive to its environment. Near-UV circular dichroism suggested that phenylalanyl and tyrosyl residues were under influence from tertiary structure.
Effect of left hepatic vein ligation on hepatic circulation, function, and microanatomy in dogs.
Eighteen healthy dogs were allotted to 3 groups (n = 6 dogs each). All dogs were evaluated at the beginning of the study by complete physical examination; total and differential WBC counts; serum biochemical analysis (alanine transaminase and alkaline phosphatase activities and bilirubin and albumin concentrations); sulfobromophthalein excretion, ammonia tolerance, and glucagon response testing; portal and intraparenchymal pressure determinations; operative mesenteric portography; and histologic assessment of hepatic biopsy specimens. The left hepatic vein was ligated completely in dogs of groups 1 and 2. Group-3 (control) dogs had a ligature placed loosely around the left hepatic vein. Dogs of groups 1 and 3 were reevaluated 24 hours after surgery by use of the aforementioned hematologic and biochemical tests. Group-1 dogs were reevaluated by use of portal and intraparenchymal pressure determinations, jejunal vein portography, and complete necropsy at 48 hours after surgery. At 4 weeks after surgery, dogs of groups 2 and 3 were reevaluated by use of all aforementioned tests. Results indicated transient hepatic congestion, which resolved by the fourth postoperative week. Longstanding effect on hepatic structure, circulation, or function was not found. We concluded that left hepatic vein ligation in clinically normal dogs does not cause severe or permanent liver damage.
How psychiatrists weigh risk factors when assessing suicide risk.
The clinical assessment of suicide risk is a difficult task that the traditional literature contributes to in a limited way. This study aims to complement the traditional literature by determining the ranking of suicide risk factors by a group of 81 psychiatrists. Hopelessness was ranked the most important risk factor, followed by Suicidal Ideation, Previous Attempts, the Level of Mood and Affect, Quality of Relationships, Signs and Symptoms of Depression, and Social Integration. Less highly ranked risk factors are also noted. The significance of these findings is discussed with respect to the literature and commonly used textbooks of psychiatry.
Psychiatrists' experience of suicide in their patients.
Ninety-nine psychiatrists from a defined geographical area were sent a questionnaire asking them to report on clinical, social and demographic characteristics of patients who suicided while under their care. Seventy-three psychiatrists returned the questionnaire and reported having seen a total of 122 suicides. This resulted in a mean of 0.12 suicides per psychiatrist per year of practice. Twenty-four percent of the patients were reported to have had a diagnosis of schizophrenia which is significantly higher than in studies based on coroner's cases. Evidence of withdrawal, considering oneself a burden to others and help negation are factors that had frequently been present in the month prior to the suicide. The authors recommend that these three factors should be examined further by using a prospective strategy.
Sequential assessment of staff administration of contingency management procedures on a child psychiatric unit.
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Dimensions of myelinated nerve fibers near the motor and sensory terminals in cat tenuissimus muscles.
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Cortical-thalamic relationships in the rat.
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