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Biomedical subjects

L Crosby

Publications and source records attributed to L Crosby.

11 recordsLinked to original sources
PubMed1992

Subcutaneous emphysema, pneumomediastinum, and potentially life-threatening tension pneumothorax. Pulmonary complications from arthroscopic shoulder decompression.

Subcutaneous emphysema, pneumomediastinum, and tension pneumothorax are previously unreported complications of shoulder arthroscopy with subacromial decompression. Three patients developed extensive subcutaneous emphysema, pneumomediastinum, and bilateral tension pneumothorax during or immediately after shoulder arthroscopy with subacromial decompression. The procedure was terminated and appropriate treatment was given. All three patients recovered completely with no residual damage. The complications are thought to be associated with the extravasation of air that may be drawn in from the lateral portal when the arthroscopic infusion pump and power shaver with suction are turned on. Early diagnosis, followed by immediate termination of the infusion pump and suction shaver along with appropriate treatment can be life-saving.

Adult↗
PubMed1990

Respiratory tract responses to dust: relationships between dust burden, lung injury, alveolar macrophage fibronectin release, and the development of pulmonary fibrosis.

A multidisciplinary approach was used to investigate the responses of the respiratory tract to silica (SiO2) or titanium dioxide (TiO2). Rats were intratracheally instilled with 5-100 mg/kg of dust and bronchoalveolar lavage fluid (BALF) lactate dehydrogenase (LDH) and total protein (TP) and ex vivo alveolar macrophage (AM) fibronectin release assessed on Days 7, 14, and 28 after exposure. Lung dust burdens were determined on Days 1, 7, and 28 after instillation. Both dusts elicited dose-related increases in BALF LDH and TP, a response which was more pronounced and progressive with SiO2. All doses of SiO2 elicited persistent increases in AM fibronectin release. TiO2 stimulated persistent increases in AM fibronectin release at greater than or equal to 50 mg/kg, with transient or no effect at less than or equal to 10 mg/kg. Increased SiO2 retention was observed for all doses and TiO2 retention was increased only at doses greater than or equal to 50 mg/kg. In vitro exposure of naive AM to SiO2 or TiO2 did not stimulate AM fibronectin release. Histopathology demonstrated fibrosis at all SiO2 doses; only TiO2 doses greater than or equal to 50 mg/kg resulted in fibrosis. These results reveal an association between increased dust retention, lung injury, activation of AM fibronectin release, and the development of fibrosis. The magnitude and temporal pattern of responses clearly differentiated SiO2 from TiO2. The correlation of BALF markers of lung injury and increased AM fibronectin release with the development of fibrosis supports the use of these parameters as predictive biomarkers of dust-induced interstitial lung disease.

Animals↗
PubMed1989

Clinical neurologic assessment tool: development and testing of an instrument to index neurologic status.

The clinical neurologic assessment tool (CNA) is a 21-item instrument assessing response to verbal and tactile stimulation, ability to follow commands, muscle tone, body position, movement, chewing, and yawning in the patient with head trauma. The CNA was developed to detect subtle changes in the patients' neurologic status that may indicate transitions in the comatose state. The CNA has been extensively pilot tested. Reliability determined by using Cronbach's alpha revealed an internal consistency of 0.96. Concurrent validity testing with the Glasgow Coma Scale indicated a strong positive correlation, r = 0.94. Construct validity was assessed with factor analysis using 0.50 for a loading criterion. Three factors were demonstrated: general level of consciousness, muscle tone and resistance, and chewing or yawning. Discriminant function analysis revealed that the CNA scores correctly classified 95.1% of the patient observations into their respective Glasgow Coma Scale categories. The CNA is reliable, valid, convenient, and easily scored and captures the subtle changes in the patient with head trauma.

Adolescent↗
PubMed1988

Morphologic and immunohistochemical evidence of human papillomavirus capsid antigen in smokeless tobacco keratoses from juveniles and adults.

Seventy-seven tissue samples from patients with either degree I, II, or III smokeless tobacco keratoses were examined. The tissues were evaluated for the presence of human papillomavirus (HPV) antigen by immunocytochemical staining. Capsid antigen could be identified in sixteen cases (20.78%). This investigation further supports the concept that smokeless tobacco-associated leukoplakias can be correlated with HPV infection.

Adolescent↗
PubMed1987

Whole body leucine, phenylalanine, and tyrosine kinetics in end-stage liver disease before and after hepatic transplantation.

The kinetics of leucine, phenylalanine, and tyrosine metabolism following orthotopic human liver transplantation in end-stage liver disease in hospitalized patients were evaluated and compared to controls. The investigation was carried out by protein turnover studies using 13C leucine, D5-phenylalanine, and [U-14C] tyrosine by continuous infusion and employing a stochastic model in 32 patients with end-stage liver disease, 17 of whom went on to receive an hepatic allograft, and 7 controls without significant liver disease who underwent elective abdominal surgery. Mean tyrosine flux in the liver disease group was 3,242 +/- 811 (n = 32) v 2,899 +/- 688 mumol/h in controls (n = 7) (P less than .001), while the tyrosine oxidation was 328 +/- 179 v 422 +/- 185 mumol/h (P less than .001). Tyrosine clearance in pretransplant patients was 719 +/- 345 (n = 17) v 1,193 +/- 568 mL/min (P less than .005) in posttransplant patients (n = 17) with virtually no overlap. There was a significant correlation between serum albumin levels and the tyrosine clearance (r = .60, P less than .05), but correlations with other conventional liver function tests were of a low order. Leucine and phenylalanine kinetics in liver disease patients did not show any significant differences from controls. Leucine and tyrosine fluxes in controls did exhibit a significant correlation (r = .70, P less than .05), but no correlation was observed in patients with liver disease. These findings indicate that the kinetics of the amino acid tyrosine are substantially altered by end-stage liver disease, with the most profound effect on tyrosine clearance.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Isotopes↗
PubMed1986

Effects of intraoperative glucose on protein catabolism and plasma glucose levels in patients with supratentorial tumors.

Animal studies suggest that hyperglycemia (glucose concentrations greater than 225 mg/dl) occurring prior to periods of brain ischemia exacerbates neurologic damage. Neurosurgical patients, a group at risk for intraoperative brain ischemia, often receive glucose. Therefore, the effects of intraoperative glucose administration (IGA) on these patients were studied. Sixteen patients undergoing supratentorial craniotomy were randomly assigned to receive either 5% glucose in 0.9% sodium chloride solution (G) or 0.9% sodium chloride solution (S) infusion (both at a rate of 3-4 ml X kg-1 X h-1) during the first 4 h of surgery. All patients received glucose infusions postoperatively. Plasma glucose, insulin, free fatty acids, alanine, ketones, base excess, pH, triglycerides, and lactate were measured during the infusion period and 24 h postoperatively. Urinary nitrogen was measured, commencing with the infusion and continuing for 24 h. Neurologic testing included preoperative and postoperative neurologic and psychomotor exams, time to extubation (min), and degree of alertness at the completion of anesthesia. The G group had significantly greater intraoperative plasma glucose concentrations at all time periods studied during the infusion (P less than 0.05). Glucose levels ranged from 200-242 mg/dl compared with 120-160 mg/dl in G and S groups, respectively. G group hyperglycemia was within the range associated with exacerbation of ischemic brain damage in animal studies. Free fatty acids and ketones were significantly greater (P less than 0.05) intraoperatively in the S group. Lactate and insulin were significantly greater in the G group at 4 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Effects of reduced left ventricular mass on chamber architecture, load, and function: a study of anorexia nervosa.

We investigated the effects of reduction in left ventricular mass on cavity geometry, afterload, pump function, and exercise performance in 17 patients with anorexia nervosa and in 10 age-and sex-matched normal subjects. Left ventricular mass index determined by two-dimensional echo-cardiography was significantly lower than that in normal subjects (53 +/- 15 vs 79 +/- 18 g/m2; p less than .005). Left ventricular end-diastolic and end-systolic volume indexes were also reduced in patients with anorexia nervosa compared with normal subjects (49 +/- 11 vs 65 +/- 17 ml/m2, p less than .005; 14 +/- 5 vs 19 +/- 4 ml/m2, p less than .025). In spite of the reductions in left ventricular mass and volume indexes, left ventricular chamber architecture described as h/R ratio, mass to volume ratio, and short/long left ventricular axis ratio were normal. Left ventricular afterload assessed as end-systolic meridional and circumferential wall stress was normal (59 +/- 18 vs 79 +/- 19 dyne/cm2 X 10(3) and 170 +/- 26 vs 167 +/- 23 dyne/cm2 X 10(3)). Ejection fraction, percent fractional shortening, and the relationship between end-systolic wall stress and ejection fraction were all within normal limits. In seven patients restudied after a 15% to 20% weight gain, left ventricular mass and volume indexes increased significantly but end-systolic wall stress and ejection fraction did not change. Ten patients with anorexia nervosa and resting heart rates and systolic blood pressures significantly lower than control values underwent treadmill testing. Exercise duration, peak heart rate, peak systolic blood pressure, and peak oxygen consumption in these patients were all significantly lower than normal. The hypotensive effect of fasting resulted in an initial decrease in afterload, which was the stimulus for reduction in left ventricular mass. The left ventricular remodeling associated with the mass reduction occurred in such a way that (1) orthogonal, meridional, and circumferential wall stresses were normalized, (2) normal chamber shape and architecture were maintained, and (3) chamber function and stress-shortening relationships were preserved. Thus down-regulation of left ventricular mass per se, like up-regulation of left ventricular mass, is not associated with abnormal left ventricular function.

Adolescent↗