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C W Thomas

Publications and source records attributed to C W Thomas.

At least 37 records · Page 2Linked to original sources
PubMed1990

Multicategory classification of body surface potential maps.

A statistical classification method is suggested for body surface potential maps (BSPM). The initial data reduction utilizes the Fourier expansion and time integration, resulting in physiological-oriented features. Based on Fischer's criterion, optimal discriminant vectors are used to map the features to an optimal subdomain. Experimental criteria determine the dimensionality of the subdomain and the number of features to be mapped into it. Classification is performed in two steps. In the first, a k-nearest neighbor (k-NN) rule is used for every two-category problem, the results of which are fed into a voting rule for final classification. The method is tested with 123 patients divided into four categories: normal (NR), ischemia (IS), myocardial infarction (MI), and left bundle branch block (LB) patients. The success is between 88% (for IS) and 100% (for LB) for QRS segment integration. Departure maps were used to explain the misclassified patterns.

Algorithms↗
PubMed1989

A cardiac potential mapping system.

The technical aspects of a multiple-purpose cardiac mapping system are presented. The authors begin with a brief history of hardware and software development and then concentrate on the major problems in acquiring high-quality recordings from the torso surface or from the epicardial surface and on the processing of the signals for display of color maps or other analysis. To achieve the desired adaptability to a variety of cardiac applications and experiments, they incorporated three parallel microprocessors that can record the signals from 240 electrodes and simultaneously provide display and analysis of the incoming cardiac data. While the parallel processors and modular software offer computational and flexibility advantages, the user interacts with an ordinary AT-compatible computer. This discussion is not a survey of the systems used in the many research laboratories or specific cardiac applications but is focused on experience in developing the specific hardware for such a multi-purpose instrument, and less specifically on the software that makes the system easy to use and adaptable to a variety of experimental and clinical situations.

Action Potentials↗
PubMed1987

Pride and purpose as antidotes to black homicidal violence.

The incidence of black male homicide is a major public menace. The lowest incidence of black male homicide was when the black power movement was visible and flourishing. Psychohistorical data support the contention that racial pride is an effective means for regulating intragroup tensions. In the absence of an Afrocentric orientation that promotes community power and self-determination, the need for self-reliance is eroded by value illnesses.The value orientation of the black movement supplied the pride used to obtain academic success, to reduce juvenile delinquency, and to help Afro-Americans to structure their lives for personal satisfactions. Blackness has always been about personal power and social control, but society does not allow much access to either for Afro-Americans. As a consequence, stress from racism is severe, asymptomatic, and multi-faceted. The best antidote to black homicidal violence comes from a pro-social effort based upon a self-image that gives a feeling of positive accomplishment and appreciation. Afrocentric pride promotes or enhances pro-social behavior.

Black or African American↗
PubMed1984

The spectrum of right bundle branch block as manifested in electrocardiographic body surface potential maps.

A wide spectrum of types of right bundle branch block (RBBB) were studied utilizing the body surface potential maps (BSPMs) of 37 children. Although the spectrum varied from very advanced RBBB to minimal partial RBBB, a common diagnostic feature was the absence of evidence for right ventricular breakthrough in the maps of all patients. Evidence for left ventricular breakthrough was usually seen, the exceptions being five patients with partial RBBB and one of 29 with advanced RBBB. The appearance of evidence for activation of the right ventricle by way of the septum was late in onset. In addition, especially in advanced RBBB, the BSPM pattern reflecting right ventricular activation was prolonged in such a manner that it appeared that utilization of right ventricular Purkinje tissue was minimal and inefficient. The BSPMs during ST-T, which were of inverse polarity, reflect repolarization that is determined by the sequence of depolarization to a greater degree than in the normal. In general, the more extensive the surgery, the more advanced the RBBB (as reflected in the BSPM), although there were exceptions. The one parameter that linked all patients with RBBB together was the absence of evidence for right ventricular epicardial breakthrough.

Adolescent↗
PubMed1984

Cytoprotective effect of prostaglandin E2 in irradiated rat ileum.

Radiation injury to the gastrointestinal tract is an infrequent but major clinical problem. Results of previous studies have shown that prostaglandins provide cytoprotection of the gastrointestinal mucosa against a variety of noxious agents, although, prior to this study, the protection against radiation exposure had not been documented. Exteriorized segment of Sprague-Dawley rat ileum was radiated with 10 and 15 Gy (137Cs). One group of rats was pretreated with prostaglandin E2 one hour before and 24 hours after radiation injury. The rats were sacrificed three and five days following radiation injury. Morphometric measurement of mucosal thickness, villous height, crypt of Lieberkühn height and number of mitosis per square millimeter swath of tissue were analyzed. Also, 125IUdR and 3HTdR were injected in a group of rats radiated with 15 Gy (137Cs). 125IUdR counts per minute per milligram of dry weight and 3HTdR labeled cells were counted and analyzed. The morphometric measurements and radioactive labeled tissue counts suggest that prostaglandin E2 has a cytoprotective effect upon irradiated rat ileum. Speculations about the possible mechanism and usefulness of this observation are included.

Animals↗
PubMed1981

Electrocardiographic body surface potential maps of the QRS of normal children.

Electrocardiographic body surface potential maps (BSPM), utilizing 180 active dry electrodes imbedded in an inflatable vest, were obtained in 40 normal children, ages 8 to 18. The potential levels of the maps are displayed as different colors. A qualitative analysis indicated that the onset of right ventricular breakthrough could always be recognized in the upstroke of the QRS by a pseudopod from a right shoulder minimum extending into an anterior maximum, at an average of 24.4 +/- 4.2 msec., for an average QRS duration of 75.0 +/- 7.1 msec. However there was considerable normal variation, particularly in the mid and late QRS. At the time of depolarization of the free walls of the ventricles, the maximum often remained anterior, with an extension posterior, even through the Frank system vectorcardiogram invariably was posterior. Most remarkable was the terminal QRS of the BSPM, where the terminal maximum may be right superior anterior, anterior superior, or right posterior, presumably reflecting the right ventricular outflow tract, the superior septum, or the posterior basal left ventricle.

Adolescent↗
PubMed1977

Penetrating torso injuries: the role of paracentesis and lavage.

Controversy still exists regarding the proper approach to patients with penetrating torso injuries. Mandatory immediate celiotomy and selective observation both have associated risks. Paracentesis with lavage is a rapid, easily performed and readily available technique which can, with a high degree of accuracy, differentiate on initial evaluation those patients with penetrating visceral injuries from those without such injuries. Complications are minimal. The use of these two procedures in evaluating penetrating torso injuries has led to improved patient care and produced major lowering of medical and socioeconomic costs.

Abdominal Injuries↗
PubMed1976

Blood lead concentrations of children and dogs from 83 Illinois families.

In comparison of blood lead concentrations (BLC) of 119 children and 94 dogs from 83 low-income suburban Illinois families, the mean BLC in the children was 8.9 mug/100 ml greater than that in the dogs. Demonstration of a BLC of diagnostic significance in a family dog increased the probability sixfold of finding a child in the same family with a BLC similarly increased. A history of pica in a family dog also increased the likelihood of finding pica in the family's children. It was concluded that family dogs may be useful sentinels of lead poisoning in children, and that veterinarians seeing dogs in clinical situations may have public health responsibilities with regard to lead poisoning.

Animals↗
PubMed1975

Blood lead concentrations in three groups of dogs from a suburban Illinois community.

Of 89 clinically normal dogs that were regular patients of a suburban Illinois veterinary hospital, all had blood-lead concentrations (BLC) within the range cited as normal in the literature. In contrast, 22% of 50 dogs from city pound and 15.3% of 98 dogs owned by low-income families of the community had BLC in excess of the normal limits. Additionally, 8% of dogs from the city pound and 4.1% of dogs from low-income families had BLC that are reported to the reliably associated with clinical lead poisoning. Socioeconomic characcteristics of the dog-owning family were more reliably associated with abnormally high BLC than were either history or clinical signs.

Animals↗
PubMed1975

Acute drug reactions among the elderly.

Research in the field of social gerontology has not examined rug use and abuse amont the aged despite the potential significance of this issue to many students of gerontology. This report, based on an analysis of the records of patients who were treated for acute drug reactions at Jackson Memorial Hospital in Miami, Florida, during 1972, examines characteristics of acute drug reactions among a sample of 60 elderly patients and compares these characteristics with those of other age cohorts. The findings show that acute drug reactions were more likely to occur among whites and females, that a substantial number of the reactions followed the ingestion of two or more substances, that roughly one-third of the admissions were directly related to suicide attempts, and that the vast majority of acute drug reactions among the elderly admissions involved the ingestion of legally manufactured and distributed drugs.

Acute Disease↗