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Biomedical subjects

J A Hall

Publications and source records attributed to J A Hall.

At least 163 records · Page 9Linked to original sources
PubMed1987

Effect of acepromazine, diazepam, fentanyl-droperidol, and oxymorphone on gastroesophageal sphincter pressure in healthy dogs.

Treatment of healthy dogs with 4 commonly used psychotropic or analgesic agents significantly decreased resting gastroesophageal sphincter pressure (GESP). Acepromazine decreased GESP by 35% (P = 0.02); oxymorphone decreased GESP by 38% (P less than 0.005); diazepam decreased GESP by 42% (P = 0.005); and fentanyl-droperidol decreased GESP by 40% (P = 0.03). Therefore, esophageal manometric evaluation of gastroesophageal sphincter function should not be preceded by administration of these drugs.

Acepromazine↗
PubMed1987

Parent-adolescent conflict: an empirical review.

Conflict between parents and adolescents is usually seen as a normal and necessary part of human development. However, treatment approaches for problematic conflict differ depending on several variables including theoretical orientation of the clinician. This article compares and contrasts psychoanalytic, systems, and social learning theories in order to determine the empirical support for each. In addition, several issues inherent in parent-adolescent conflict are reviewed including developmental stage theory, parenting styles, peer pressures, communications skills, marital conflict, drugs, school, and sex. Several studies and reviews of the literature are examined for common conclusions. Finally, an integrated and empirically supported model to explain parent-adolescent conflict is described.

Adolescent↗
PubMed1986

The action of factor Xa on peptide p-nitroanilide substrates: substrate selectivity and examination of hydrolysis with different reaction conditions.

Kinetic parameters for the action of bovine Factor Xa (EC 3.4.21.22) on 25 commercially available peptide p-nitroanilides have been determined. The selectivity constant, kc/Km, ranges from 1.5 X 10(1) to 2 X 10(6) M-1 X s-1 for the poorest and the best substates, respectively. The best substrates for Factor Xa were identified as those with arginine in the P1 position, and glycine in the P2 position. Quantitative distinction between lysine and arginine in the P1 position and other amino acids in the P2-P4 positions of the substrate is reported from the changes in the kinetic parameters for substrates differing in only a single amino acid in these positions. Effect of NaCl and CaCl2 concentrations and temperature on the action of Factor Xa on selected substrates have been assessed. Km values for Factor Xa hydrolysis of most substrates are greater than 100 microM. Solubility of the substrates consequently restricts measurements of reaction velocities to concentrations lower than desirable for optimally determining kc. Comparison of these kinetic parameters for Factor Xa with those of thrombin (Lottenberg, R., Hall, J.A., Blinder, M., Binder, E. and Jackson, C.M. (1983) Biochim. Biophys. Acta 742,539-557) for these same substrates indicates that the greater hydrolytic efficiency of thrombin is due primarily to lower Km values.

Anilides↗
PubMed1986

Reaction of thrombins with human antithrombin III. I. Enzyme activity losses unrelated to the inhibitory reaction and their prevention.

Adsorption loss of thrombin may produce considerable systematic error when quantitative evaluation of its reaction with antithrombin III is based on measurements of changes in enzyme activity with time. At 25 degrees C, pH 7.8 (0.1 M NaCl, 0.01 M TRIS, 0.01 M HEPES) glass, siliconized glass, polypropylene and polystyrene surfaces adsorb thrombin in a similar manner. Its adsorption is a saturation reaction reaching an equilibrium after about three hours. At initial concentrations of enzyme convenient for assay with chromogenic substrate (10 nM or less) a large fraction of activity is lost. Binding of alpha thrombin to polypropylene is very tight. The association constants (Ka) were found to be 12.6 X 10(9) M-1 and 4.0 X 10(9) M-1 for human and bovine alpha thrombin respectively. The adsorbed enzyme has hardly any ability to hydrolyze chromogenic substrate. A small part of its activity can be recovered by displacement with PEG 6000, more when the substrate is present. The addition of non-ionic detergents and continuous stirring allows recovery of up to 30% of the enzyme activity and accelerates this process. Complete and long term (more than 20 hours at 25 degrees C) prevention of adsorption loss of human alpha and bovine alpha and beta thrombin at pH between 7.0-8.3 is achieved by the addition of 0.1% PEG 6000 to the buffer and use of tubes precoated with PEG 20,000. Alternative use of non-ionic detergents (BRIJ-35, TRITON X-100) to modify the solvent also appears effective but their possible interference with reactions studied should be borne in mind.

Adsorption↗
PubMed1986

Postoperative anatrophic nephrolithotomy bleeding.

We reviewed 530 patients treated with anatrophic nephrolithotomy during a 14.5-year period. Significant postoperative renal bleeding occurred in 34 cases (6.4 per cent). The average postoperative blood transfusion requirement in this group was 5,279 cc. Bleeding patients were significantly older and they had worse renal function compared to the nonbleeding group. If bleeding did not begin immediately it usually started 5 to 8 days postoperatively. Bleeding dyscrasias were identified in 6 patients and correction allowed nonoperative management in 4. Epsilon aminocaproic acid was helpful only in the treatment of patients with slow, lower volume bleeding. Eight patients required 9 open renal explorations to control bleeding. Two arteriovenous fistulas and 1 false aneurysm were identified. An attempt at angiographic embolization of an arteriovenous fistula was unsuccessful. Only 1 patient required a nephrectomy (1 of 34 or 2.9 per cent) and there was no mortality. A treatment plan for this complication is described.

Adult↗
PubMed1986

Large brain metastasis not shown by computerized tomography.

We have described a patient with metastatic small cell carcinoma of the lung in whom cranial CT and contrast-enhanced CT failed to show metastases. When the patient died four days later, two sizable intracerebral metastatic foci were found at autopsy. Reviewing previously reported causes of nonvisualization of lesions, we have speculated on reasons for the lack of CT findings in this case.

Aged↗
PubMed1986

High thoracic disc herniation.

A case of T-1, T-2 disc herniation is reported. The patient presented with diminished hand strength, medial arm and shoulder pain, and medial arm, forearm, and hand paresthesias. After surgical decompression and removal of a disc fragment, the patient made a complete recovery. Routine cervical myelography was considered inadequate in view of this patient's symptoms. High thoracic myelography followed by computed tomographic scanning should be considered for patients with this presentation. Improved diagnosis with myelography and computed tomography is discussed.

Humans↗
PubMed1985

The incorporation of O6-methyldeoxyguanosine monophosphate and O4-methyldeoxythymidine monophosphate into polynucleotide templates leads to errors during subsequent in vitro DNA synthesis.

O4-MedTMP and O6-MedGMP may be incorporated from their 5'-triphosphates into polynucleotides by DNA polymerases. Once incorporated O6-MedGMP leads to errors during further cycles of DNA synthesis with a mutagenic efficiency of 0.3-0.7, the value depending upon the relative dNTP concentrations in the assay. In contrast O4-MedTMP leads to very few errors following its incorporation into DNA. The results demonstrate that O6-MedGMP, once incorporated into DNA, should be destined to give rise to DNA base changes during the second round of DNA synthesis.

DNA Replication↗
PubMed1985

Pediatric anatrophic nephrolithotomy.

A 15-year experience with pediatric anatrophic nephrolithotomy was reviewed. There were 11 procedures performed in 10 patients. Average patient age was 9.43 plus or minus 1.54 years (standard error of the mean). Preoperative urine cultures were positive in 6 of 11 cases. Metabolic or structural defects were identified in all patients. Postoperative morbidity was minimal. Adequate followup was available in 9 patients, for an average length of 4.6 plus or minus 0.96 years. Stones recurred in 7 of 9 patients (78 per cent) but in 2 the new calculi were small and asymptomatic. Anatrophic nephrolithotomy can be performed safely in children but a high incidence of structural and metabolic abnormalities predisposes these patients to recurrent stones.

Adolescent↗
PubMed1985

Type A behavior, nonverbal expressive style, and health.

Understanding the precise nature of the links among styles of behavior, emotional expression, and the development of heart disease is a major challenge in psychology and health. In the present research, 60 men at high risk for coronary heart disease were examined in terms of their expressive style, their specific nonverbal cues, their personality, and their health. As assessed by the self-report Jenkins Activity Survey (JAS; Jenkins, Zyzanski, & Rosenman, 1979), half the men were Type A and half were Type B. To provide a more refined grouping, the men were further classified on the basis of scores on the Affective Communication Test (ACT; H. S. Friedman, Prince, Riggio, & DiMatteo, 1980), a self-report measure of nonverbal expressiveness. In the framework of theory and research on nonverbal expressive style, videotapes of the men were extensively rated and coded in terms of their judged appearance, the actual audio and video nonverbal cues emitted, and the words said (transcript). Two groups of Type A individuals were found--one that was repressed, tense, and illness-prone, but another that was healthy, talkative, in control, and charismatic. Furthermore, in addition to the expected healthy Type B men, a subgroup of Type B men was found who were submissive, repressed, tense, have an external locus of control, and may be illness-prone. A refined conception of the Type A behavior pattern is deemed necessary in light of these findings. Implications for improving the validity of the Type A construct and understanding the link between psychosocial factors and disease are discussed.

Adult↗
PubMed1985

Chest radiographic findings in neonates on extracorporeal membrane oxygenation.

Eight full-term neonates with pulmonary failure were managed with extracorporeal membrane oxygenation (ECMO). Chest radiographs obtained before and during ECMO support were reviewed. During periods of increased flow requirements, the chest radiographs were difficult to evaluate because of increasing pulmonary opacity. During periods of the infants' clinical improvement, their chest radiographs tended to improve as well. A direct cause-and-effect relationship between the pulmonary density and the ECMO flow requirements has not yet been established. The chest radiographs were reliable in confirming correct catheter positions. Routine daily examinations did not demonstrate unsuspected abnormality. Chest radiography during periods of clinical instability, however, added confirmatory evidence to some clinical diagnoses and assisted us in making the diagnosis of an unexpected pneumothorax.

Extracorporeal Circulation↗
PubMed1985

Audit of screening for hypertension in general practice.

An audit of a practice which has a policy of opportunistic screening for raised blood pressure showed that 80 per cent of patients born between 1930-44 had been screened in the last five years. Patients who had not been screened were identified and contacted; this increased the percentage screened to 87 per cent. Only four possible new hypertensives were identified. It is suggested that the effort and expense of achieving this result was not worthwhile and that opportunistic screening is the cheapest and easiest method of screening for high blood pressure.

Adult↗