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Biomedical subjects

R Delaney

Publications and source records attributed to R Delaney.

At least 19 recordsLinked to original sources

The value of crossed intrinsic transfer after metacarpophalangeal silastic arthroplasty: a comparative study.

Seventy three hands in patients with rheumatoid arthritis undergoing primary index to small finger metacarpophalangeal joint replacements were studied retrospectively. In twenty eight hands a crossed intrinsic transfer was performed and in forty five hands it was not. A similar splintage and rehabilitation programme was followed in each group. The two treatment groups had similar preoperative ulnar drift (crossed intrinsic transfer group mean 27 degrees, comparative group 29 degrees). At a mean follow up of 50 months the crossed intrinsic transfer group had statistically less ulnar drift (crossed intrinsic transfer group mean 6 degrees, comparative group mean 14 degrees, P=0.01). There were no other significant differences at follow up.

Adult↗

Gender differences in cognitive and neural correlates of remembrance of emotional words.

Studies suggest that men and women have important differences in specific cognitive functions. Men show superior spatial memory and women demonstrate superior verbal memory, and women rely on emotional content to a greater degree in the processing of information. In spite of extensive research in neural correlates of human cognition, little is known about possible gender differences or the role of emotional content in the mediation of cognition. Two sets of lists of word pairs were developed, one with neutral (e.g., school-grocery) and the other with emotional (e.g., mutilate-beat) content. Male and female subjects were asked to rate emotions related to the words on several dimensions (e.g., nervous, fearful, happy). In a second experiment, men and women underwent positron emission tomographic (PET) measurement of brain blood flow during retrieval of word pairs. Words in the "emotional" category were rated more highly on the emotional dimensions, and women rated them as having more emotional impact than did the men. During retrieval of emotional words (but not neutral words) there was a different pattern of activation among the women compared with the men, with greater activation in bilateral posterior hippocampus and cerebellum, and decreased activity in medial prefrontal cortex, which are brain areas previously implicated in emotion. There were no significant differences in retrieval of emotional versus neutral words, or in differences in memory performance between men and women. The findings suggest differences in cognitive appraisal and involvement of a broader network of brain regions mediating emotion during remembrance of emotional words in women compared with men.

Adolescent↗

Preliminary evidence of low cortical GABA levels in localized 1H-MR spectra of alcohol-dependent and hepatic encephalopathy patients.

OBJECTIVE: The aim of the study was to compare levels of neuroactive amino acids in the cerebral cortex of healthy subjects, recently detoxified alcohol-dependent patients, and patients with hepatic encephalopathy. METHOD: Metabolite levels were measured in the occipital cortex by using spatially localized 1H-MRS. Five recently detoxified alcohol-dependent and five hepatic encephalopathy patients with alcohol and non-alcohol-related disease were compared with 10 healthy subjects. RESULTS: The combined level of gamma-aminobutyric acid (GABA) plus homocarnosine was lower in the alcohol-dependent and hepatic encephalopathy patients than in the healthy subjects. CONCLUSIONS: The findings suggest that GABA-ergic systems are altered in both alcohol-dependent and hepatic encephalopathy patients.

Adult↗

Deficits in short-term memory in adult survivors of childhood abuse.

Exposure to stress has been associated with alterations in memory function, and we have previously shown deficits in short-term verbal memory in patients with a history of exposure to the stress of combat and the diagnosis of posttraumatic stress disorder (PTSD). Few studies of any kind have focused on adult survivors of childhood physical and sexual abuse. The purpose of this study was to investigate short-term memory function in adult survivors of childhood abuse. Adult survivors of severe childhood physical and sexual abuse (n = 21), as defined by specific criteria derived from the Early Trauma Inventory (ETI), who were presenting for psychiatric treatment were compared with healthy subjects (n = 20) matched for several variables including age, alcohol abuse, and years of education. All subjects were assessed with the Wechsler Memory Scale (WMS) Logical (verbal memory) and Figural (visual memory) components, the Verbal and Visual Selective Reminding Tests (SRT), and the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Adult survivors of childhood abuse had significantly lower scores on the WMS Logical component for immediate and delayed recall in comparison to normal subjects, with no difference in visual memory, as measured by the WMS or the SRT, or IQ, as measured by the WAIS-R. Deficits in verbal memory, as measured by the WMS, were associated with the severity of abuse, as measured by a composite score on the ETI. Our findings suggest that childhood physical and sexual abuse is associated with long-term deficits in verbal short-term memory. These findings of specific deficits in verbal (and not visual) memory, with no change in IQ, are similar to the pattern of deficits that we have previously found in patients with combat-related PTSD.

Adult↗

Subanesthetic effects of the noncompetitive NMDA antagonist, ketamine, in humans. Psychotomimetic, perceptual, cognitive, and neuroendocrine responses.

BACKGROUND: To characterize further behavioral, cognitive, neuroendocrine, and physiological effects of subanesthetic doses of ketamine hydrochloride in healthy human subjects. Ketamine, a phencyclidine hydrochloride derivative, is a dissociative anesthetic and a noncompetitive antagonist of the N-methyl-D-aspartate subtype of excitatory amino acid receptor. METHODS: Nineteen healthy subjects recruited by advertisements from the community participated in this randomized, double-blind, placebo-controlled study. Subjects completed three test days involving the 40-minute intravenous administration of placebo, ketamine hydrochloride (0.1 mg/kg), or ketamine hydrochloride (0.5 mg/kg). Behaviors associated with the positive and negative symptoms of schizophrenia were assessed by using the Brief Psychiatric Rating Scale. Changes in perception and behaviors associated with dissociative states were assessed by the Perceptual Aberration Subscale of the Wisconsin Psychosis Proneness Scale and the Clinician-Administered Dissociative States Scale. Cognitive function was assessed by using the (1) Mini-Mental State Examination; (2) tests sensitive to frontal cortical dysfunction, including a continuous performance vigilance task, a verbal fluency task, and the Wisconsin Card Sorting Test; and (3) tests of immediate and delayed recall. Plasma levels of cortisol, prolactin, homovanillic acid, and 3-methoxy-4-hydroxyphenethyleneglycol were measured. RESULTS: Ketamine (1) produced behaviors similar to the positive and negative symptoms of schizophrenia; (2) elicited alterations in perception; (3) impaired performance on tests of vigilance, verbal fluency, and the Wisconsin Card Sorting Test; (4) evoked symptoms similar to dissociative states; and (5) preferentially disrupted delayed word recall, sparing immediate recall and postdistraction recall. Ketamine had no significant effect on the Mini-Mental State Examination at the doses studied. Ketamine also had no effect on plasma 3-methoxy-4-hydroxyphenethyleneglycol levels, although it blunted a test day decline in plasma homovanillic acid levels at the higher dose. It also dose dependently increased plasma cortisol and prolactin levels. Ketamine produced small dose-dependent increases in blood pressure. CONCLUSIONS: These data indicate that N-methyl-D-aspartate antagonists produce a broad range of symptoms, behaviors, and cognitive deficits that resemble aspects of endogenous psychoses, particularly schizophrenia and dissociative states.

Adult↗

Defensive coping and blood pressure reactivity in medical patients.

Two defensive coping styles, denial of illness and repressive coping, were studied in two groups of medical patients whose blood pressure (BP) was measured during a stress interview. Denial of illness was measured using the Levine Denial of Illness Scale (LDIS), and repressive coping was measured using a combination of the Marlowe-Crowne (MC) Social Desirability Scale and the SCL-90R anxiety subscale (ANX). Consistent with our prior research indicating that LDIS was associated with adaptive outcomes in the short run, high deniers manifested reduced systolic BP reactivity compared to low deniers. Although not related to repressive coping, systolic BP reactivity was correlated positively with MC and ANX separately. The results demonstrate that LDIS and MC measure different types of defensive coping. Current theories of the MC scale suggest two possible interpretations of the MC findings, one that focuses on avoidant coping and the second on attentional coping in high MC scorers.

Adaptation, Psychological↗

Decontamination of chemical protective clothing.

This study explored decontamination procedures for removing some organic solvents from protective clothing. The permeation experiments were performed on new and decontaminated specimens in seven polymer/chemical pairs. The decontamination methods investigated were thermal decontamination and air drying at room temperatures followed by detergent washing. Breakthrough time and steady-state permeation rate were determined by two different methods for new and decontaminated materials. The results showed that unless the contamination is limited to the outside surface of an elastomer (a material found in most barrier fabrics used in chemical protective clothing) or the chemical has a very large diffusion coefficient in the material, aeration and washing with detergent may not be an effective decontamination procedure for the type of solvent studied. On the other hand, thermal decontamination was shown to be effective in removing the contaminant from the matrix of the elastomers, and the decontaminated materials had permeation parameters similar to the new materials.

Decontamination↗

Amino acid sequence of rhizopuspepsin isozyme pI 5.

The complete amino acid sequence of an aspartic protease from Rhizopus chinensis, rhizopuspepsin isozyme pI 5, has been determined. Partial sequences were first obtained from the isolated isozyme by a combination of chemical and proteolytic enzyme cleavages, peptide purifications, and Edman degradations. About one-half of the sequence was revealed by this approach. To complete the amino acid sequence, a cDNA library of R. chinensis in pBR322 was constructed. An oligonucleotide probe was synthesized based on the sequence Trp-Trp-Gly-Ile-Thr, and about 40 positive clones were identified by colony hybridization. A clone, 33E2, which had an insert size of about 1.1 kilobase pairs, was found to contain the entire coding region of rhizopuspepsin isozyme pI 5. The sequence of rhizopuspepsin contains 325 amino acid residues. The alignment of the rhizopuspepsin sequence against other aspartic proteases revealed expected homology, with the closest similarity to penicillopepsin which shares 39% identical residues. Porcine pepsin shares about 36% identical residues with rhizopuspepsin.

Amino Acid Sequence↗

Relationship of lipoamide dehydrogenases from Pseudomonas putida to other FAD-linked dehydrogenases.

Pseudomonas putida produces two lipoamide dehydrogenases, LPD-glc and LPD-val. LPD-val is specifically required as the lipoamide dehydrogenase of branched-chain keto acid dehydrogenase and LPD-glc fulfills all other requirements for lipoamide dehydrogenase. Both proteins are dimers with one FAD per subunit. LPD-glc has an absorption maximum at 455 nm, but LPD-val has a maximum at 460 nm. Comparison of amino acid compositions revealed that LPD-glc was more closely related to Escherichia coli and pig heart lipoamide dehydrogenase than to LPD-val. LPD-val did not appear to be closely related to any of the proteins compared with the possible exception of mercuric reductase.

Amino Acids↗

Nutritional support of the acutely ill patient.

Administration of nutritional support in acutely ill patients can be seen as a balance between the need to provide nutrients and the known complications associated with infusions of each of the three major nutrients--glucose, fat, and protein. It is prudent to maintain calorie intake within reasonable limits. If facilities for measurements of O2 consumption and hence metabolic rate are available, these should be utilized. Otherwise, metabolic rate should be estimated. In patients who are in satisfactory nutritional condition and who are being nourished to preserve lean body mass, diets designed to maintain body cell mass should be utilized. Practically speaking this means an energy intake of 1.0 to 1.2 times the daily energy expenditure and an N intake of 200 to 300 mg/kg/day. In patients where the goal is restoration of lean body tissue, a nutritional regimen designed to achieve a positive calorie and N balance should be used. This generally means an energy intake of 1.4 to 1.6 times the energy expenditure, with a N intake of 250 to 400 mg/kg/day. The nonprotein calories are administered as 50% glucose and 50% fat. These recommendations are based on studies performed to data. The area of nutritional support of the acutely ill patient is under extensive investigation. It is likely that as more data are collected, these guidelines will be revised.

Acute Disease↗

Liquid culture of Rhizopus chinensis for the production of acid protease rhizopuspepsin.

1. Culture conditions for the production of rhizopuspepsin in liquid medium by Rhizopus chinensis have been investigated. 2. Optimum production was achieved in 24 hr shaking culture in 1% bovine serum albumin, 1% corn starch, 0.1% yeast extract and a salt mixture, pH 5. 3. Levels at 24 hr compared in isozyme pattern and in quantity to conventional solid culture on wheat bran.

Aspartic Acid Endopeptidases↗

Purification and characterization of rhizopuspepsin isozymes from a liquid culture of Rhizopus chinensis.

1. Rhizopuspepsin has been purified from liquid cultures of Rhizopus chinensis. 2. Purification by ammonium sulfate precipitation, affinity chromatography on pepstatin Sepharose and low/high resolution isoelectric focusing produced five isoelectric forms. 3. The two major isozymes pI 5.1 and 5.8 did not differ significantly in amino acid composition, molecular weight and enzyme activity. 4. Three minor isozymes were partially purified as pI 7.35, 7.41 and 7.9.

Aspartic Acid Endopeptidases↗

Fractionation and reconstitution of vitamin K-dependent carboxylation activity in rat liver microsomes.

Attempts to purify the vitamin K-dependent carboxylation system from rat liver microsomes have not yet met with success. Purification procedures result in low yields of activity even after relatively mild separation methods. We have been able to demonstrate that one reason for these failures is that there are at least two components (which can be separated) necessary for the reaction. Recombination of the separated components is possible if the detergent (Triton X-100) concentration is lowered and ethylene glycol is added to the system. Under these conditions, vitamin K-dependent carboxylation of synthetic pentapeptide (Phe-Leu-Glu-Glu-Leu) can be totally reconstituted.

Animals↗

Regulation of vitamin K-dependent carboxylation.

Vitamin K-dependent carboxylation activity measured with pentapeptide substrate (Phe-Leu-Glu-Glu-Leu) gradually decreases upon in vivo injection of vitamin K to vitamin K-deficient rats. A decrease in pentapeptide carboxylation can also be observed by the in vitro addition of antibodies against prothrombin and other vitamin K-dependent proteins to the soluble system derived from vitamin K-deficient rat liver microsomes. In both cases, adding back in vitro partially decarboxylated vitamin K-dependent proteins or purified hepatic prothrombin precursor restores the level of pentapeptide carboxylation. After warfarin treatment, a 3-fold increase in carboxylation results, which can be abolished by giving cycloheximide along with the warfarin. However, the resulting decreased activity is restored by the in vitro addition of partially decarboxylated vitamin K-dependent proteins. These data are consistent with the hypothesis that (after warfarin treatment) increased peptide carboxylation is primarily due to activation of the system by precursor proteins, rather than synthesis of an increased amount of enzyme.

Animals↗

Purification of a new high activity form of glucose-6-phosphate dehydrogenase from rat liver and the effect of enzyme inactivation on its immunochemical reactivity.

A new form of cytoplasmic glucose-6-phosphate dehydrogenase (E.C.1.1.1.49) was purified from rat liver by protamine sulfate precipitation, ammonium sulfate fractionation, ion exchange chromatography with diethylaminoethyl cellulose, and affinity chromatography with Cibacron blue agarose and NADP agarose. This form of the enzyme has a specific activity of over 600 units/mg of protein and gives essentially a single band by polyacrylamide gel electrophoresis. The form of the enzyme isolated by this purification method is 3 times more active than the form purified from liver by previously reported procedures. The relative mass of this pure glucose-6-phosphate dehydrogenase enzyme was determined by disc gel electrophoresis to be 269,000. This high activity glucose-6-phosphate dehydrogenase enzyme, after inactivation by reaction with palmityl-CoA, was no longer precipitated by specific rabbit and goat antisera to this purified enzyme. Thus, the possibility still exists that starved fat-refed animals contain glucose-6-phosphate dehydrogenase (G6PD) enzyme protein in an inactivated form no longer detectable by either enzyme activity or immunoprecipitation.

Animals↗