Intraluminal shunt for the thoracic aorta: spinal cord and visceral blood flow in acute studies.

Aortic cross-clamping during surgery of the thoracic aorta may result in paraplegia or kidney failure. Difficulties associated with external shunts and bypasses have limited their use. Therefore we compared intraluminal shunting to the nonshunting method of repair in neonatal pigs. Blood flow to the spinal cord and viscera was measured with radiolabeled microspheres before, during, and after thoracic aortic cross-clamping or shunting. Two no-shunt groups were studied: One group was clamped distal to the left subclavian artery for 30 minutes and the other for 1 hour. In the intraluminal shunt group, a shunt was placed in the aorta just below the ligamentum arteriosum for 1 hour; it was then removed and the aorta repaired. In the no-shunt groups, there was virtually no blood flow to the lower cord and viscera during the cross-clamp period. Hyperemia of the lower thoracic and lumbar cord occurred in the no-shunt 30-minute group 15 minutes after clamp removal. In the no-shunt 60-minute group, flow initially returned to the lumbar cord but then declined; and after 1 hour of reperfusion it was significantly lower than baseline. Renal blood flow was even more severely affected in the no-shunt 60-minute group, with minimal recovery during the reperfusion period. In the intraluminal shunt group baseline spinal cord and visceral blood flow were maintained during thoracic aortic cross-clamping, without the problems associated with extracorporeal circulation.

Passive exposure to cocaine in medical personnel and its effect on urine drug screening tests.

This report studies the importance of passive exposure of medical personnel to cocaine hydrochloride and its impact on urine screening testing. Eleven medical staff members were exposed to cocaine hydrochloride by means of aerosol and cutaneous application, similar to that which may occur in medical practice. Urine drug screening tests were negative for everyone tested. This finding is supported by known drug kinetics. It is unlikely that a single passive exposure of medical staff to cocaine hydrochloride will produce a positive urine screening test. In all cases of positive urine tests, contaminants should be tested for which may indicate a source of the drug. The routine use of gloves and masks--which is recommended to prevent HIV infection--should further decrease medical personnel's passive exposure to cocaine hydrochloride.

Protected bronchoalveolar lavage. A new bronchoscopic technique to retrieve uncontaminated distal airway secretions.

We tested the effectiveness of protected bronchoalveolar lavage (PBAL), performed through a protected transbronchoscopic balloon-tipped (PBT) catheter, in collecting distal airway secretions with a minimal degree of contamination. The PBAL had less than or equal to 1% squamous epithelial cells in 91% of specimens and an absence of bacterial growth in 59% of patients without pneumonia. Using a threshold of 10(4) cfu/ml we had one false positive result in 33 patient without pneumonia and one false negative in 13 patients with pneumonia. Quantitative bacterial cultures of the PBAL specimens had a diagnostic sensitivity of 97% and a specificity of 92%, with a positive predictive value of 97% and a negative predictive value of 92%. The diagnostic efficiency was 96%. The presence of intracellular organisms in much greater than or equal to 2% of the recovered alveolar cells (Giemsa stain) was seen in all but two patients with pneumonia (on corticosteroids) and in none of the patients without pneumonia. Gram stains of the PBAL specimens were positive in all but one patient with pneumonia and negative in all but one patient without infection (patient with endobronchial narrowing secondary to neoplasm with false positive cultures). Either the Giemsa or the Gram stain was positive in all patients with pneumonia, allowing early and accurate diagnosis of lower respiratory tract infection before the results of cultures were available. The time off antibiotic therapy before bronchoscopy did not affect the result of PBAL cultures, contrary to what we observed for the protected brush specimen.

Extramedullary hematopoiesis within the hypotympanicum presenting as a glomus tympanicum.

We discuss the case of a 22-year-old black woman who presented with a mass in the left hypotympanicum. Both the pre- and postoperative diagnosis of the lesion was a glomus tympanicum. Histopathologic examination revealed the "tumor" to be a nodule of extramedullary hematopoiesis. Many sickled erythrocytes were also noted within the lesion. A multilingual literature search (English, French, German, Spanish, Portuguese, Italian, and Russian) failed to reveal a documented case of extramedullary hematopoiesis in the hypotympanicum. We assume that the patient's hemoglobinopathy was the cause of her unusual focus of extramedullary hematopoiesis.

Renal involvement by histiocytic medullary reticulosis.

The case of a young man who died seven months after the diagnosis of histiocytic medullary reticulosis is reported. Autopsy and laboratory findings were consistent with a diagnosis of uremia. Liver, lymph nodes, spleen, and bone marrow were involved by neoplastic cells. In addition, the kidneys were massively involved by tumor. Previously published autopsy studies of this rare condition failed to demonstrate massive renal involvement.

Pulmonary hyalinizing granuloma.

We describe a recent case of pulmonary hyalinizing granuloma presenting classically in a young black American female. The diagnosis was made by histopathologic examination. The etiology of this entity remains elusive, however, an abnormal response involving the immune system to an undefined agent (or agents) is the most likely explanation.

High-pressure liquid chromatography and enzyme immunoassay compared with gas chromatography for determing phenytoin.

We compared a gas-chromatographic method for determination of phenytoin with a high-pressure liquid chromatographic technique and with enzyme immunoassay by three instrumental procedures. More than 100 sera from patients being treated with this drug were assayed by all these techniques. The coefficient of variation was the lowest (4.0%) with liquid chromatography, but all methods gave a CV of less than 10%. The correlation coefficients for all methods exceeded 0.97 when compared to gas chromatography. Operation costs varied with the number of tests per batch, reagent costs, and operator labor costs. All assays gave comparable values for the therapeutic range, so it would be plausible to use more than one method in a situation where (e.g.) satellite laboratories handle different quantities of assays. In any of these techniques, interferences from carbamazepine, mephenytoin, phenobarbital, and primidone were negligible.

Theophylline and dyphylline levels in serum by liquid chromatography.

The widespread use of theophylline and dyphylline as bronchodilators in the treatment of acute and chronic obstructive airway disease, and recognition of the need to control the therapeutic drug level has created a demand for fast accurate measurement techniques. Measurement of theophylline levels by ultraviolet spectrophotometric techniques is hindered by interferences from barbiturates and caffeine, and thermal lability of the drug necessitates derivatization if gas chromatography is to be used. Because of these factors, a liquid chromatographic method has been developed which allows separation of the underviatized drug from interfering compounds, and quantitation of the theophylline in a single operation. In addition, the drug-containing fraction can be readily collected and subjected to mass spectral examination if there is any question as to its identify. The latter feature has particular significance in medico-legal cases.