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Biomedical subjects

J J Cunningham

Publications and source records attributed to J J Cunningham.

At least 37 records · Page 2Linked to original sources
PubMed1991

Zinc and copper status of severely burned children during TPN.

Alterations in zinc (Zn) and copper (Cu) homeostasis have been reported during the acute recovery period following thermal injury in both children and adults. Increased urinary losses of Zn and Cu and decreased plasma concentrations of Zn, Cu, and ceruloplasmin (CP), the major copper transport protein, occur despite adequate provision of these elements in enteral feedings. We now report data for moderately to severely burned children receiving total parenteral nutrition (TPN) supplemented to provide Zn and Cu. Hyperzincuria occurred consistently when 50 micrograms/kg Zn was delivered daily to older children. Similarly, when younger children received 100 micrograms/kg Zn daily, profound hyperzincuria ensued despite a reduction in total plasma Zn. Hypozincemia was accompanied by low levels of Zn in the plasma subfraction normally associated with albumin-bound Zn. The delivery of Cu via TPN was 4-12 micrograms/kg daily, and urinary Cu losses were not elevated. Plasma total Cu and plasma CP were invariably reduced. These findings are discussed in relation to guidelines published for pediatric trace element supplementation during TPN.

Adolescent↗
PubMed1991

Body composition as a determinant of energy expenditure: a synthetic review and a proposed general prediction equation.

Differences in body composition have often been examined in conjunction with measurements of energy expenditure in men and women. Numerous studies during the past decade examined the relationship between resting energy expenditure (REE) and the components of a two-compartment model of composition, namely the fat-free mass (FFM) and the fat mass (FM). A synthetic review of these studies confirms a primary correlation between REE and FFM in adults over a broad range of body weights. A generalized prediction equation is proposed as REE = 370 +/- 21.6 x FFM. This equation explains 65-90% of the variation in REE. Several studies suggest, further, that FFM predicts total daily energy expenditure (TDEE) equally well. An independent contribution by FM to the prediction of either REE or TDEE is not supported for the general population, perhaps reflecting the relative constancy of the absolute FM in nonobese individuals. In the subset of obese women, FM may be a significant predictor.

Adult↗
PubMed1990

Cystic thyroid nodules. The dilemma of malignant lesions.

A retrospective study of 221 surgically resected thyroid nodules disclosed that 71 (32%) were cystic and 150 (68%) were solid lesions. Ultrasonography correctly characterized cystic nodules in all but one case. Comparing cystic and solid nodules, there were no differences in patient demographics (mean ages, 47.7 +/- 1.8 SEM vs 45.9 +/- 1.2 years; sex, 78% females both groups), the proportion that were solitary (39% vs 40%), or the nodule size (49% vs 47% greater than or equal to 2 cm in diameter). Of cystic thyroid lesions, 4% were simple cysts, 82% were degenerating benign adenomas or colloid nodules, and 14% were malignant compared with 23% of solid lesions that were malignant. Most cystic lesions (81%) contained bloody fluid. One benign true cyst was filled with thick brown fluid, while clear yellow fluid was repeatedly aspirated from one malignant cystic nodule. Malignant fine-needle aspiration cytology was the best predictor of cancer (100%). Much less predictable were signs of local compression or invasion (43%), a history of head or neck irradiation (33%), cyst recurrence after aspiration (29%), or an increase in the cystic nodule's size (7%). Indeterminate cytology identified malignancy with about half the frequency in cystic lesions as compared with solid nodules (13% vs 27%). The only false-negative fine-needle aspiration cytology occurred in a cystic lesion. In patients with cystic papillary cancers, needle aspirates contained insufficient material for diagnosis in 20% that occurred in no patient with solid papillary carcinoma. The sensitivities and specificities of fine-needle aspiration cytology for solid nodules were 100% and 55%, and for cystic nodules were 88% and 52%. Thus, cystic lesions are as likely as solid thyroid lesions to harbor a malignancy that cannot be predicted from the cyst's clinical characteristics or the patient's demographic data. Although fine-needle biopsy is the best predictor of malignancy in either cystic or solid thyroid lesions, it is slightly less reliable when a thyroid lesion is fluid filled rather than solid. We believe that most cysts not abolished by aspiration should be surgically excised.

Adult↗
PubMed1990

Sonographic "white line sign" for detection of minimal mucosal thickening in renal transplants.

It is important to detect minimal hydronephrosis in a renal transplant because early or low-grade obstruction is clinically significant. Similarly, it is equally important to detect minimal mucosal thickening of the collecting system because this finding indicates the presence of renal disease even though thickening itself is nonspecific as to etiology. Differentiating between minimal hydronephrosis and minimal mucosal thickening may be difficult. We have noticed that meticulous sonograms made with an ultrasound transducer placed perpendicular to the interface of two opposing surfaces of thickened mucosa will produce a bright linear echo which can help discover and distinguish between these two entities. We choose to call this echo complex the "white line sign."

Adult↗
PubMed1990

Calorie and protein provision for recovery from severe burns in infants and young children.

Severely burned adults increase their metabolic energy expenditure (MEE) to levels approaching twice the normal resting metabolic rate (RMR). There are no available measurements of MEE for severely burned infants and toddlers, however, and nutritional support relies on published estimates of MEE that range from 200% to 400% of RMR. We determined the actual calories provided to 10 infants and children ages 3-33 mo during acute care for severe burns (59 +/- 5% total-body-surface burn). Our standard protocol emphasizes the delivery of amino acids at 3 g.kg-1.d-1 in conjunction with prompt excision and grafting. An anabolic state characterized by weight maintenance and healing was supported with far fewer calories than predicted by four published formulas for MEE. We conclude that when greater than 2.5 g.kg-1.d-1 protein is provided, efficient protein utilization for recovery is achieved with calorie provision at 120-200% RMR in severely burned infants and toddlers.

Burn Units↗
PubMed1990

Cholangiocarcinoma occurring after childhood radiotherapy for Wilm's tumor.

Some patients have been given radioactive thorium dioxide as an intravascular contrast agent. Retained particles of thorium in the liver have chronically irradiated hepatic tissues and sometimes caused cholangiocarcinomas and other malignancies. We studied a young woman who developed cholangiocarcinoma in liver tissue which was included in the field of external beam therapy given for Wilm's tumor some twenty years earlier. Radiation-induced cholangiocarcinoma may not necessarily require chronic exposure to ionizing radiation.

Adenoma, Bile Duct↗
PubMed1989

Measured and predicted calorie requirements of adults during recovery from severe burn trauma.

Major burn trauma produces large elevations in metabolic energy expenditure (MEE) during acute care. However, overfeeding can occur and is detrimental to recovery. The formulae often used to estimate caloric support to meet MEE are based on body weight, predicted resting metabolic rate (RMR), body surface area, or the total body surface area burned (BSAB). These predictive equations originate from studies of less than or equal to 30 patients generally lacking measurements beyond the third week of convalescence. We report 565 measurements by indirect calorimetry for 122 adults between the burn day and day 149 postburn. A standardized protocol of nutritional support and early wound closure was followed. Predictions of MEE are compared in subcategories of BSAB (2-25%; 30-50%; 51-75%; and 76-98%). For major burns exceeding 30% BSAB, 2X the predicted RMR was consistently closest to the measured MEE, assuring adequate calorie provision while minimizing the risk of overfeeding.

Adult↗
PubMed1988

Methotrexate and bone marrow metaphases.

The efficacy of a methotrexate (MTX) block/thymidine release synchronization technique has been assessed in bone marrow cultures from patients with acute nonlymphocytic leukemia and myelodysplasia. In contrast to cultures of stimulated lymphocytes from normal individuals, no improvement in mitotic index (MI) or metaphase quality could be detected using this technique. Demonstration of an unchanged level of division in bone marrow cultures in the presence of MTX suggests that the technique is unsuitable for synchronization purposes in this tissue. The influence of preincubation prior to MTX exposure and duration of exposure to colcemid on MI and metaphase quality have also been examined.

Adolescent↗
PubMed1988

Altered vitamin C transport in diabetes mellitus.

Tissues sequester vitamin C in concentrations exceeding that present in plasma. The transmembrane transport mechanisms have been shown to be influenced by the concentration of glucose in vitro. On this basis an impairment of tissue vitamin C status may be present in diabetes mellitus. Recent evidence in support of this hypothesis, first proposed by Mann in 1974, is reviewed.

Ascorbic Acid↗
PubMed1988

Chronic intracerebroventricular CRF infusion attenuates ACTH-corticosterone release.

Bolus intracerebroventricular delivery of corticotropin-releasing factor (CRF) elicits acute responses of both the pituitary-adrenal axis and the sympathetic nervous system. We examined whether these stresslike responses could be maintained over a period of days by central delivery of CRF in nonstressed rats, as would be predicted if this peptide participates in the central nervous system regulation of chronic stress. CRF (4.3 or 21.5 micrograms/day) was continuously delivered into the cerebral ventricle via Alzet minipumps. In contrast to saline-infused controls, rats receiving CRF exhibited elevated excretions of corticosterone, norepinephrine, and urea nitrogen for several days. Thereafter, an attenuation of CRF responsiveness occurred when corticosterone excretion returned to basal levels despite continued central CRF infusion. However, CRF delivered intravenously during attenuation stimulated adrenocorticotropic hormone and corticosterone secretion, implicating a hypothalamic rather than pituitary locus for central CRF resistance. The present data do not permit a conclusion on whether the attenuation of the CRF response with time is the result of an ultrashort-loop negative-feedback mechanism or CRF receptor desensitization.

Adrenocorticotropic Hormone↗
PubMed1986

In vivo total body electrical conductivity following perturbations of body fluid compartments in rats.

Total body electrical conductivity (TOBEC) provides a rapid and safe noninvasive technique for the assessment of total body water in animals and man. An instrument employing this principle has been shown to measure body water in healthy Sprague-Dawley rats. With the exception of adult obesity in humans, alterations in body fluid compartments that could theoretically affect the utility of conductivity measurements have not been studied. We, therefore, applied the total body electrical conductivity measurement in rats following perturbations of body fluid/electrolyte spaces including obesity, furosemide diuresis, severe burn, and low protein diet. Our findings confirm that total body water can be accurately measured by TOBEC in conditions of abnormal body fluid distribution. However, when the ratio of intracellular to extracellular fluid is significantly reduced, such as the severe burn or low protein intake, TOBEC does not reflect the intracellular (potassium) space but does predict total water and extracellular (sodium) space.

Animals↗
PubMed1986

Closed-circuit metabolic system with multiple applications.

A closed-circuit metabolic system has been designed and tested for multiple applications. Air pressure within a closed chamber is regulated electronically while allowing for respiratory gas exchange. Compared with a previously reported standard indirect calorimetry system, the new device had by virtue of longer duration of measurement improved precision (coefficient of variation 3% vs. 14%) during studies of O2 consumption both at room temperature and at 5 degrees C. In addition, a more physiological atmospheric environment is maintained. This system has also been utilized for simultaneously labeling groups of up to 20 weanling rats with 18O2 over a 2-day period and for exposure of rats to a hyperoxic (84% O2), normobaric environment for 4-day periods. Potential applications include maintenance of pressure (hypobaric through hyperbaric) and O2 (hypoxic through hyperoxic) controlled environments, exposure to toxic gases, study of diurnal variations in metabolic rate, measurement of metabolic expenditure with activity, and adaptation to other species including humans.

Animals↗