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Biomedical subjects

J Green

Publications and source records attributed to J Green.

At least 631 records · Page 35Linked to original sources
PubMed1981

The evaluation of plasmin and streptokinase activator complexes in a new rabbit model of venous thrombosis.

A new quantitative model for the examination of potential thrombolytic agents is described. A thrombus was formed in the inferior vena cava of the rabbit, using 125 I-labelled fibrinogen mixed with a standard amount of thromboplastin. The thrombus was anchored securely by means of a woollen thread inserted longitudinally into the lumen of the vein. Thrombotic extension of the radioactive clot and rethrombosis during the experimental period (5 h) were prevented by the administration of intravenous heparin. In control animals, the thrombus remained stable and there was no rise in te radioactivity of the circulating blood during 5 h. In animals given thrombolytic agents, lysis could be followed continuously by measuring the rise in blood radioactivity. Total lysis was determined by counting the radio-label in the residual clot after treatment. The model has been used to study the thrombolytic activity of streptokinase-human plasminogen complexes, activator-free plasmins of human and porcine origin, and human plasmin produced by streptokinase (SK) activation of human plasminogen. The role of activator complexes in the thrombolytic activity of SK-activated plasmin is discussed.

Animals↗
PubMed1981

The thrombolytic activity of streptokinase in the rabbit.

The activity of streptokinase (SK) has been examined in a rabbit model of venous thrombosis. Significant thrombolysis was observed at low doses of SK without evidence of systemic activation of the fibrinolytic system. The origin of the specificity of SK-induced fibrinolysis in the rabbit was explored, using a chromogenic substrate coupled assay to measure the enhancement of plasmin generation in the presence of rabbit fibrin. The results obtained suggest that rabbit fibrin influences the fibrinolytic system at three points, viz: the assembly of an activator complex from rabbit plasminogen and SK; the activity of that activator complex towards further rabbit plasminogen; and the activity of the resulting rabbit plasmin in the presence of plasma inhibitors.

Animals↗
PubMed1981

Fibrinolysis with acyl-enzymes: a new approach to thrombolytic therapy.

Deep vein thrombosis in man presents a considerable clinical challenge. Despite the availability of prophylactic measures, therapeutic thrombolysis is often necessary, but is difficult and hazardous. Treatments have included the administration of plasmin, other less specific proteolytic enzymes, the indirect plasminogen activator, streptokinase, and the direct activators, urokinase and streptokinase-human plasmin complex. All these treatments have been associated with some haemostatic breakdown, which has discouraged their widespread application. The enzyme components of the coagulation and fibrinolytic pathways can, in general, be classed as serine proteases, with a catalytic mechanism which operates via acyl-enzyme intermediates. Chase and Shaw showed that p-nitrophenyl-p'-guanidinobenzoate could specifically acylate the active centre of trypsin-like enzymes, giving rise to a stable p-guanidinobenzoyl enzyme and other stable acyl-enzymes have since been described. We report here the fibrinolytic use of acylated derivatives of plasmin (E.C.3.4.21.7) and streptokinase-plasmin(ogen) complexes.

Acylation↗
PubMed1981

Reliability of psychiatric diagnosis in hospitalized adolescents. Interrater agreement using DSM-III.

To determine the reliability of psychiatric diagnosis in hospitalized adolescents, 95 consecutively admitted patients were diagnosed independently by two experienced clinicians using DSM-III criteria. Diagnostic judgments were based on joint interview of the patient via a structured mental-status examination, nursing observations, and referral materials. Concordance was analyzed by the kappa coefficient. A total of 13 DSM-III categories were used to classify this cohort, with the majority of categories representing traditional syndromes of functional psychopathology. There was complete agreement between the raters for more than three fourths of the patients. Levels of agreement for the categories of schizophrenia and major affective disorder were similar to values obtained in recent studies of adult patients. The results are discussed in relation to historical conceptions of adolescent psychopathology.

Adolescent↗
PubMed1981

Phenomenology and subtypes of major depressive disorder in adolescence.

The authors systematically evaluated the prevalence and reliabilities of a large set of depressive symptoms and subtypes of major depressive disorder in 40 hospitalized adolescents, aged 12-17. Results indicated that the phenomenology of depressive illness in this age group is distinguished by descriptive features akin to traditional clinical formulations. Psychotic, retarded and endogenous subtypes were documented, although they are less prevalent than in adult depressives. Overall, the reliabilities of symptom and subtype ratings were found to be very satisfactory. Results were discussed with respect to current theoretical conceptions of juvenile affective illness and directions for further research.

Adolescent↗
PubMed1980

A review of the Laceys' physiological hypothesis of heart rate change.

The Laceys have devised a physiological hypothesis to explain the observation that sometimes the response of an organism to a task is a cardiac deceleration. They have suggested that a fall in heart rate and blood pressure may serve to reduce the tonic inhibitory influence of the baroreceptors on CNS activity. This serves to make the organism better prepared to intake sensory stimuli and respond to them. The hypothesis suggests that small increases in blood pressure should cause cortical inhibition. A review of the literature suggests that small changes in blood pressure within the normal range may have little influence on CNS activity in the alert animal. Furthermore available evidence suggests that small increases in blood pressure may exert an excitatory influence on CNS functioning in common with other sensory stimuli, where any effect can be discerned. It is concluded that the literature in general does not support the Laceys' physiological hypothesis.

Animals↗
PubMed1980

Abuse potential of loperamide.

Effects of the currently marketed form of loperamide (Imodium capsules) that might relate to abuse potential were examined. Study I was a double-blind "dose run-up" in adult male subjects with a history of illicit drug use but no history of opioid addiction. Subjective responses to doses of loperamide ranging from 12 to 60 mg were compared with responses to 120 mg codeine sulfate (96 mg base) and to placebo. Based on study I, loperamide (60 mg) was used in study II and its effects were compared with those of codeine (96 mg base) and placebo in an exaddict subject group. Study II subjects had had extensive opioid experience but were not actively addicted at the time of this double-blind, inpatient study. In study II, as in study I, unlike loperamide and placebo, codeine induced pupillary constriction. Loperamide (60 mg) induced a detectable subjective effect in somewhat over half the subjects, was "liked" little or not at all, and was identified as "dope" at a frequency less than that for a threshold dose of oral codeine. It was concluded that in its present form, i.e., capsules containing loperamide mixed with magnesium stearate, loperamide poses little threat of potential abuse.

Adult↗
PubMed1980

Exercise testing after beta-blockade: improved specificity and predictive value in detecting coronary heart disease.

The value of exercise testing in detecting myocardial ischaemia resulting from coronary atheroma remains controversial. In order to increase the reliability of exercise testing, all its components (asymptomatic, haemodynamic, and electrocardiographic) have been scrutinised. In this study, concerned only with the electrocardiographic response to exercise, the incorporation of beta-blockade into the standard exercise procedure has improved specificity and predictive value without affecting sensitivity. Fifty patients with anginal pain and 50 asymptomatic subjects with an abnormal electrocardiogram were investigated by exercise testing before and after beta-blockade (oxprenolol). All subjects had coronary arteriograms and left ventriculograms, and the results of exercise testing were related to the presence or absence of obstructive coronary artery disease. Possible causes of false positive exercise tests were eliminated by echocardiography. Though beta-blockade was unreliable in distinguishing ischaemic from non-ischaemic resting electrocardiograms, it eliminated all the false positive electrocardiographic responses to exercise in both groups and did not abolish any of the true positive electrocardiographic responses. Thus, specificity and predictive value were improved without reduction in sensitivity. This technique may not necessarily be applicable to other groups of patients or to a random population, but the results of this study suggest it will be a useful additional routine procedure in the investigation of coronary heart disease.

Adolescent↗
PubMed1980

Brain stem auditory evoked responses in clinical practice.

A relatively new noninvasive technique for the diagnosis of abnormalities affecting the central nervous system is presented. It is especially useful in patients with acoustic neuroma, brain stem disorder such as tumors of the posterior fossa with neuraxis impingement, as well as demyelinating disorders such as multiple sclerosis. It is certainly useful in the verification of neurologic normalcy in patients complaining of dizziness and vertigo.

Acoustic Stimulation↗
PubMed1980

Clinical utility of ambulatory EEG monitoring.

Our initial clinical experiences with the "Oxford" ambulatory nontelemetry EEG monitoring shows that it is a useful and economical device for monitoring EEG and EKG activity in patients in a normal environment. Careful selection of the patient with possible seizure disorder and emphasis on temporal lobe recordings may give a higher degree of diagnostic yield in questionable cases of seizure. Further investigations utilizing this modality (ambulatory EEG monitoring) appears to be fully warranted. Further study, carefully controlled with regard to patient selection, age, chief complaint and previous EEG findings is currently underway at the Neurological Institute, Inc.

Adolescent↗
PubMed1980

The family-oriented clinical simulation: an interdisciplinary tool for professional growth.

An interdisciplinary, educational technique--the family-oriented clinical simulation--is described and compared and contrasted to other commonly used role-playing techniques. Implications for training and supervision of physical therapists and other health care professionals are discussed, including the technique's relevance as a vehicle for studying in an applied clinical context the interface of physical disease and its psychosocial manifestations. The article concludes with a description of the benefits and potential disadvantages of the technique.

Allied Health Personnel↗
PubMed1979

A system for the three-dimensional construction, manipulation and display of microbiological models.

A system is described for building up serial sections into a three dimensional structure, incorporating density, that can be displayed and then further manipulated by rotation about three orthogonal axes. The initial application was to produce a computer model of a protein structure and to compare the diverse images obtained from rotation with the two dimensional images observed in related electron micrographs. To obtain sufficient contrast in the electron microscope images of protein structures, the specimens need to be stained and since this can cause some deformation of the observed images, it is also necessary to simulate ths possible effects of stain on the protein model. Because of the need to compare numerous orientations of the combined model, techniques are available either for speeding up the comparison or for obtaining better accuracy. The methods have been applied to the interpretation of electron micrograph images of microbiological specimens, where the three dimensional structure of the specimen is an important aid in understanding its biological function, but the techniques are also applicable to more general serial reconstruction requirements.

Adenoviridae↗