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Biomedical subjects

C D White

Publications and source records attributed to C D White.

47 records · Page 3Linked to original sources
PubMed1991

Post menopausal bleeding as a risk factor for endometrial carcinoma.

From July 1985 to January 1989, 133 patients underwent endometrial sampling for evaluation of post menopausal bleeding (PMB). Of these patients, 114 (85.7 percent) showed benign histology with an average age of 58.6 years. Nineteen (14.3 percent) were malignant, all of which showed endometrial carcinoma. The average age was 65. In addition, 26.3 percent of patients with carcinoma had higher grade of tumor at hysterectomy when compared with the preoperative biopsy. The average volume of tissue removed at curettage was significantly greater in those with carcinoma. Hormonal therapy, duration of symptoms, hypertension, obesity or diabetes were not significant risk factors for carcinoma in our series. PMB remains a major symptom that may predict endometrial carcinoma and must be evaluated. In those patients with carcinoma, intraoperative evaluation of the uterus for tumor grade and depth of invasion is important in determining the extent of surgery.

Adult↗
PubMed1990

The gynecologist's role in the treatment of breast carcinoma.

The treatment of early carcinoma of the breast remains contraversial. One hundred eleven cases of stage I and II carcinoma of the breast treated from January 1985 to November 1988 were reviewed. Given an informed choice, 13 of the 30 patients (43.3%) treated by the author chose breast conservation over mastectomy, in striking contrast to a 97.5% incidence of mastectomy in the 81 patients treated by the general surgeons on the hospital staff. The role of the gynecologist in the treatment of breast cancer can be to offer a different viewpoint and thus possibly to become a major force in the reduction in the number of mastectomies.

Breast Neoplasms↗
PubMed1986

Pathophysiology of soman intoxication in primates.

Adult baboons were monitored during intravenous infusion of Soman (1,2,2-trimethylpropyl ester, phosphonofluoridate). Three groups of animals were studied. Two groups were anesthetized with sodium pentobarbital (initial dose, 20 mg/kg), instrumented for measurement of systemic blood pressure (BP), pulmonary artery pressure, cardiac output (CO), ECG, ventilatory flow, translaryngeal pressure (PTL), transdiaphragmatic pressure (Pdi), transpulmonary pressure (PTP), diaphragm EMG, and efferent phrenic nerve traffic (Eph). One group received no Soman and served as controls. In the other group, Soman was infused over 10 min at doses of 13.1, 8.21, 4.92, or 3.3 micrograms/kg. The onset of intoxication occurred within 7-8 min (before the end of the 10-min infusion), manifested by muscular fasciculations, stridorous breathing, copious secretions, and atrioventricular arrhythmias. Mean BP decreased to 30 mm Hg by the combination of decreased CO and decreased vascular resistance. There was a dose-related response in the onset and duration of these effects. Apnea occurred in most animals and coincided with cessation of the Eph signal. Stimulation of the diaphragm via the phrenic nerve following apnea yielded Pdi values unchanged from baseline, indicating an intact neuromuscular apparatus. All animals required ventilatory support. Some surviving animals exhibited severe behavior changes. The third group of animals was studied without anesthesia. Instrumentation was performed 3 days before using a tether system for the measurement of BP, CO, and ECG, and an arterial line for blood withdrawal. Soman was infused over 10 min at a dose of 13.1 micrograms/kg. The onset of intoxication occurred within 2-3 min, manifested by hyperactivity, severe muscle fasciculations which simulated grand-mal convulsions, stridorous respiratory sounds, copious secretions, and cardiac arrhythmias. Apnea and severe lactic acid acidosis developed in all animals and all required ventilatory assistance. None recovered spontaneous ventilation at the end of 4 hr.

Animals↗
PubMed1986

Prognostic features of vulvar melanoma: a clinicopathologic analysis.

We studied 19 cases of vulvar melanoma to determine significant clinical and histologic prognostic predictors. The average follow-up time was 32 months. Fourteen patients died of melanoma, four patients are alive with no evidence of melanoma, and one patient is alive with residual melanoma. All disease-free survivors had clinical stage I disease and a maximum tumor thickness of 1.3 mm. The average mitotic count in this group was 5.5 per 10 high power fields (HPF) and 50% of the tumors were superficial spreading melanomas. All survivors were treated by radical vulvectomy with bilateral inguinal lymph node dissection. Of the nonsurvivors, four (28.5%) were clinical stage I, five (36%) were clinical stage II, four (28.5%) were clinical stage III, and one (7%) was clinical stage IV. The average tumor thickness for nonsurvivors was 9.5 mm (range 2.6-18 mm) and the average mitotic count was 13.3/10 HPF. Only three (21%) tumors from nonsurvivors were superficial spreading melanomas; the majority were nodular melanomas. The statistically significant prognostic predictors were clinical stage of disease and tumor thickness. Tumor type (i.e., superficial spreading, nodular, or acral lentiginous) correlated with tumor thickness and was indirectly related to prognosis. The mitotic count was also a useful prognostic feature.

Adult↗
PubMed1984

The prognostic significance of tumor emboli in lymphatic or vascular spaces of the cervical stroma in Stage IB squamous cell carcinoma of the cervix.

The presence of tumor emboli in lymphatic or vascular spaces within the cervical stroma in squamous cell carcinoma of the cervix has been reported by several authors to be associated with a decrease in 5-year survival. In a 10-year review of 124 radical hysterectomies for Stage IB squamous cell carcinoma of the cervix at the University of Michigan from 1970 to 1980 the presence of tumor emboli in the cervical stroma without other known risk factors did not significantly alter the 3- and 5-year survival. With the potential risks and lack of proved benefit the use of adjuvant radiotherapy or chemotherapy in this setting is not recommended.

Adult↗
PubMed1984

Does dopamine modulate rate of decay of activation in the rostral brain?

The hypothesis that dopaminergic systems affect rate of decay of activation in at least some sites in the rostral brain involved in the selection and patterning of behaviours is explored. Behavioural evidence appears to support the hypothesis, but insufficient neurophysiological data are available to evaluate it directly.

Animals↗
PubMedDate not supplied

Effects of image orientation on the comparability of pediatric brain volumes using three-dimensional MR data.

PURPOSE: The purpose of this study was to examine the comparability of morphometric measurements made on pediatric data sets collected at five scanner locations, each using variations on a 3D spoiled gradient-recalled echo (SPGR) pulse sequence. METHOD: Archived MR data from 60 typically developing children were collected and separated into seven groups based on the pulse sequence used. A highly automated image-processing procedure was used to segment the brain data into white tissue, gray tissue, and CSF compartments and into various neuroanatomic regions of interest. RESULTS: Volumetric comparisons between groups revealed differences in areas of the temporal and occipital lobes. These differences were observed when comparing data sets with different image orientations and appeared to be due to partial volume averaging (PVA) and susceptibility-induced geometric distortions. CONCLUSION: Our results indicate that slice selection and image resolution should be controlled in volumetric studies using aggregated data from multiple centers to minimize the effects of PVA and susceptibility-induced geometric distortions.

Adolescent↗
PubMedDate not supplied

Functional brain imaging study of mathematical reasoning abilities in velocardiofacial syndrome (del22q11.2).

PURPOSE: Children with velocardiofacial syndrome (VCFS) often have deficits in mathematical reasoning. Previous research has suggested that structural abnormalities in the parietal lobe region might underlie these deficits. The present study utilized functional magnetic resonance imaging (fMRI) to explore the relationship between brain function and mathematical performance in VCFS. METHODS: Eight children with VCFS and eight comparison subjects underwent fMRI scanning and completed an arithmetic computation task. RESULTS: In the VCFS group, increased activation was observed in the left supramarginal gyrus (LSMG) as the task difficulty increased. CONCLUSION: Aberrant LSMG activation, possibly due to structural deficits of the left parietal lobe, may explain decrements in arithmetic performance observed in VCFS.

Adolescent↗
PubMedDate not supplied

A conscious baboon model for evaluation of hemodynamics in altered gravity.

A model was developed for evaluation of cardiovascular parameters in conscious baboons exposed to altered gravitational environments. Baboons were trained to sit quietly in a confinement chair of unique design which allowed a range of normal physical activity. They were then instrumented with high-fidelity blood pressure transducers in the aorta and left ventricle, electromagnetic flow probes encircling the proximal ascending aorta, left and right atrial fluid catheters, left ventricular sonomicrometer crystals in a 3-axis configuration, and a hydraulic occluder cuff encircling the inferior vena cava. Catheters and transducer wires were exteriorized at the midscapular region of the back. Viability of percutaneous exit sites was enhanced by use of velour cuffs on the transducer wires, providing a scaffold for wound healing. Pressure transducers and flow probes were calibrated and balanced during postoperative cardiac catheterization procedures. This instrumentation allowed measurement of beat-to-beat stroke volume and cardiac output not reliant on thermodilution techniques. Postoperative longevity was from 1 to 10 months. Instrumentation failure included endocardial trapping of ventricular pressure transducers, corrosion of ventricular sonomicrometer crystals, and catheter tip thrombosis. Acquisition of high quality data was possible with this model in several different environments of altered gravitational stress, allowing characterization of aortic flow and ventricular performance.

Animals↗
PubMedDate not supplied

A method for repeated high-fidelity micromanometer measurement of intracardiac pressures.

Dial-tipped, high-fidelity micromanometers were inserted through polyurethane catheters to acutely measure blood pressures within the chambers of the heart and the great vessels of baboons, rhesus monkeys, and goats. Repeated measurements of atrial, ventricular, aortic, and pulmonary artery pressure were possible with this method, with calibration of micromanometers accomplished immediately prior to and after pressure recordings to assure data accuracy. All attempts to pass micromanometers into the atria in all species were successful. Passage of micromanometers from the left ventricle across the aortic valve and into the aorta was successful in 97% of the attempts in baboons, 100% for rhesus monkeys, and 75% for goats; while insertions into the pulmonary artery from the right ventricle were successful in 64% of the baboons, 40% of the rhesus monkeys, and 75% of the goats. Advantages of this technique are that a permanent conduit for cardiac vascular access is available and that high-fidelity pressure signals may be acquired.

Animals↗