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Biomedical subjects

K S White

Publications and source records attributed to K S White.

At least 37 records · Page 2Linked to original sources
PubMed1993

Evaluation of the craniocervical junction in Down syndrome: correlation of measurements obtained with radiography and MR imaging.

Measurement of the atlas-dens interval is the radiographic standard for identification of patients with Down syndrome at high risk for neurologic injury from spinal cord compression. In 17 pediatric patients with Down syndrome, measurements of the atlas-dens interval, distance between the clivus and posterior odontoid process, and width of the neural canal obtained with plain radiographs were compared to predict the width of the subarachnoid space on magnetic resonance (MR) images. In all patients, cervical radiography and craniocervical MR imaging were prospectively performed during lateral flexion and extension. The width of the subarachnoid space was measured with MR imaging. When the 95% confidence interval for correlation coefficients of regression was used, subarachnoid space width on MR images correlated with neural canal width on radiographs better than with either atlas-dens interval or clivus-posterior odontoid process distance (P = .05). Measurement of neural canal width is a better predictor of potential spinal cord compression than the atlas-dens interval or clivus-posterior odontoid process distance and should be emphasized in screening examinations performed with plain radiography.

Adolescent↗
PubMed1992

The cervical tube pedicle flap: uses in facial reconstruction.

Most reconstructive surgeons will not commonly need to use the transverse cervical tube pedicle flap in facial reconstruction but this straightforward and simple technique can be very useful in certain instances. Some of the techniques of reconstructive surgery which have stood the test of time should not be forgotten even when the most recent reconstructive options are available.

Adult↗
PubMed1992

Imaging of nephroblastomatosis: an overview.

Nephroblastomatosis is an abnormality of nephrogenesis characterized by incomplete maturation of primitive nephrogenic cells. The resultant individual lesions have variable histologic findings and distribution in the kidney. There is wide acceptance of nephroblastomatosis as a precursor lesion to Wilms tumor. Consequently, the role of imaging in assessing patients for neoplastic transformation of nephroblastomatosis should be emphasized. Computed tomography (CT) has been shown to be superior to ultrasound (US) in this regard. Nonetheless, the low cost and lack of radiation of US make it attractive for serial screening studies. Although magnetic resonance imaging shows promise in assessment of the kidney for nephrogenic rests, experience is limited in its use in evaluating patients for nephroblastomatosis. The authors present protocols for assessing patients identified as being at either high or low risk for the development of Wilms tumor due to nephroblastomatosis. These protocols take into account the advantages of CT and US. Scanning intervals are determined from epidemiologic data on the occurrence of Wilms tumor; the most intense screening occurs during the younger ages of life, when the likelihood of Wilms tumor development is highest.

Clinical Protocols↗
PubMed1992

Imaging of abdominal masses in children.

Abdominal imaging has undergone extensive change over the past several years. In many cases, the developments have been so rapid as to preclude an orderly comparison of competing procedures with prospective comparison studies. Consequently, no rigid imaging protocol will be universally accepted and many issues are unresolved. This article reviews the various imaging procedures used in imaging pediatric abdominal masses with emphasis on technique, indications, risks, and costs. The relative merits of imaging modalities in various clinical situations are outlined and specific recommendations are given.

Abdominal Neoplasms↗
PubMed1991

Patient awareness of health precautions after splenectomy.

Sepsis after splenectomy is a lifelong risk, and patients who have had splenectomy should be educated about this risk. This study examines patient knowledge after splenectomy. We reviewed hospital records of 118 patients who had splenectomies performed between 1982 and 1988 at New Hanover Memorial Hospital. Twenty-four patients have died since their surgery; one death was suspected to be due to postsplenectomy sepsis. Of the 89 patients alive and eligible for follow-up, we were able to query 63. Only 16% were aware of any health precautions. After prompting, patient awareness improved to 40%. We also surveyed 11 of the 14 surgeons who performed the splenectomies. They indicated that they always discuss with their patients the immunologic consequences of spleen removal and the increased risks of infection, although they do not always recommend pneumococcal vaccine. We conclude that splenectomy patients have a low level of knowledge about postsplenectomy infection risks and precautions. We developed an educational pamphlet to aid the surgeon in patient education.

Awareness↗
PubMed1991

John Caffey Award. Determination of functional residual capacity from digital radiographs of the normal neonatal chest: studies in a rabbit model.

Spirometric measurement of lung volume in an infant or uncooperative child is often a difficult and time-consuming procedure. Previous investigators have successfully estimated total lung capacity in adults and older children by using chest radiography. The purpose of this study was to assess the accuracy of functional residual capacity (FRC) determination from chest radiographs in an animal model of the normal neonatal chest. FRC was determined with the helium dilution (HeD) method in 13 anesthetized, intubated, and paralyzed rabbits (weight range, 1.5-3.9 kg). FRC was then estimated from digital frontal and lateral chest radiographs. The radiographic estimate was made by applying measurements taken from the radiographic film pair to a geometric model of the chest. The best-fit model assumed an elliptical cross section for the intrathoracic cavity, heart, paraspinal structures, and diaphragm in the axial plane. Linear regression on independently determined HeD and radiographically determined FRC yielded a slope of 1.02 (p less than .001), an intercept of -3.02 cm3 (p = .565), and a correlation coefficient of 0.96 (p less than .001). We conclude that radiographic FRC estimates closely approximate HeD estimates in a rabbit model of the normal neonatal chest.

Algorithms↗
PubMed1990

Perceptual characteristics of the amiloride-suppressed sodium chloride taste response in the rat.

The contribution of amiloride-sensitive membrane components to the perception of NaCl taste was assessed by using a conditioned taste aversion procedure. Eight independent groups of adult rats were conditioned to avoid either 0.1M NaCl, 0.5M NaCl; 0.1M NH4Cl, or 1.0M sucrose while their tongues were exposed either to water or to the sodium transport blocker amiloride hydrochloride. In contrast to rats exposed to water during conditioning, rats exposed to amiloride were unable to acquire a conditioned taste aversion to 0.1M NaCl. Differences in the acquisition of taste aversions between the amiloride- and nonamiloride-treated groups were not apparent when the conditioned stimulus (CS) was 0.5M NaCl, 0.1M NH4Cl, or 1.0M sucrose. Although the magnitude of the 0.5M NaCl aversion was similar between amiloride- and non-amiloride-treated rats, the perceptual characteristics of the CS differed between groups. Analyses of stimulus generalization gradients revealed that amiloride-treated rats generally avoided all monochloride salts after conditioning to 0.5M NaCl but not nonsodium salts or nonsalt stimuli. In contrast, rats not treated with amiloride only generalized the 0.5M NaCl aversion to sodium salts. No differences in generalization gradients occurred between groups when the CS was 0.1M NH4Cl or 1.0M sucrose. These findings suggest that the "salty" taste of NaCl is primarily related to the amiloride-sensitive portion of the functional taste response in rats. Conversely, the portion of the NaCl response insensitive to amiloride appears to have "sour-salty" perceptual characteristics and does not appear to be perceived as being salty.

Amiloride↗
PubMed1988

Simultaneous chemotherapy and radiotherapy for squamous cell lung cancer.

Simultaneous chemotherapy and radiotherapy was evaluated in 13 patients with inoperable, limited stage squamous cell lung cancer. The chemotherapeutic agents bleomycin, methotrexate, 5-fluorouracil, vinblastine, and cisplatin were administered on days 1 and 5 of two treatment cycles given 5 weeks apart. Radiation therapy was given in three 2-week cycles, the first two starting on the second day of each chemotherapy cycle and the third starting 3 weeks after the second course of radiation. The total dose was 5000-5500 rad (50-55 Gy) in 180 rad fractions. The objective response rate (complete response + partial response) was 85%, with 38% complete responders. Median survival was 7 months with two patients surviving 34 months, one with disease and one disease-free. Treatment toxicity was predominantly hematopoietic and renal. Two patients died with massive pulmonary hemorrhage while receiving treatment and a third patient died of acute respiratory failure 1 month after completing therapy. The severe toxicity and the failure to obtain long duration tumor control makes this regimen unsuitable for future use.

Aged↗
PubMed1986

Total parathyroidectomy and forearm autotransplantation for chronic renal failure: a useful tool for the general surgeon in private practice.

We reviewed 12 cases of chronic renal failure in patients with secondary hyperparathyroidism who had total parathyroidectomy and forearm autotransplantation during the years 1978 to 1984. All had elevated parathyroid hormone and calcium levels before the procedure. Using a technique previously described, with relatively large parathyroid grafts in the forearm, calcium levels were effectively reduced and maintained below the upper limit of the normal range (10.5 mg/dl). Only one patient had symptomatic hypocalcemia postoperatively. Phosphorous levels were also significantly reduced to more physiologic values. When necessary, the forearm autografts allowed simplified titration of calcium levels on an outpatient basis.

Adult↗
PubMed1985

Digital separation of primary and scatter components of chest radiographs.

This article describes a technique for digital separation of the primary and scatter components of a radiographic image. The method involves mathematical modeling of the process whereby an antiscatter grid reduces scatter patterns in film radiographs. Two superimposable radiographs (one taken with and the other without an intervening antiscatter grid) are applied to the model. Performance characteristics of the grid (primary and scatter transmittance factors) are also determined and used in the model. Radiographs of a humanoid chest phantom are processed. Scatter/primary separation appears to be accurate to within 15%. Film images that are quantitatively faithful to the calculated primary and scatter fields are included.

Analog-Digital Conversion↗
PubMed1984

Application of a computerized medical decision-making process to the problem of digoxin intoxication.

A computerized medical decision-making system was used to monitor signs and predisposing factors of digoxin intoxication in patients receiving digoxin. This process automatically reviewed the patient's data base nightly for drug interactions, laboratory data and electrocardiographic findings with known association with digoxin intoxication. These decisions were formated into a "digoxin alert report" and sent to line printers in the nursing division to be placed on the individual patients' charts. To assess the effect of these reports on patient management, a randomized double-blind study was undertaken. Patients were assigned to an alert or nonalert group. Alert reports were withheld from charts of patients in the nonalert group. A medical record review was subsequently carried out, wherein the physician's orders were searched to identify actions taken with possible relation to the digoxin alerts. The computer monitored 396 patients over a 3 month period. Of these, 211 (53%) were randomized to the alert group and 185 (47%) to the nonalert group. Seventy-two percent of patients received at least one alert. The most frequently occurring alerts included: hypoxemia, hypokalemia, concurrent use of a beta-adrenergic blocking agent, renal insufficiency and ventricular arrhythmia. Results from the record review demonstrated a 22% increase in physician actions for the alert group. Specifically, patients in the alert group were 2.7 times more likely to have a serum digoxin determination ordered and 2.8 times more likely to have digoxin withheld on the day of a digoxin alert than were patients in the nonalert group.

Aged↗