Use of Gianturco self-expandable stents in the tracheobronchial tree

Gianturco self-expandable stents were used successfully in the management of 5 patients with tracheobronchial pathology. Placement was performed under endoscopic and fluoroscopic guidance. None of the patients has experienced complications secondary to the stent placement, and in all of them the clinical problems resolved satisfactorily. Longer follow-up is required to determine the place of tracheobronchial stenting in patients with respiratory compromise.

Compression in the treatment of leg telangiectasia: a preliminary report

The use of postsclerotherapy compression was evaluated in 37 women with bilaterally symmetrical telangiectatic leg veins. Compressed vessels tended to achieve a greater clinical resolution when located on the distal leg and/or when greater than 0.5 mm in diameter. Postsclerotherapy hyperpigmentation fell from 40.5% to 28.5% with the use of compression. In addition, ankle and calf edema were lessened if a graduated compression stocking was worn immediately after sclerotherapy.

Vertical ocular motor apraxia

We report a case of vertical ocular motor apraxia in a 4-year old boy whom we have followed for 2 years. The patient had no upward and downward voluntary movements of the eyes since birth, but horizontal movements were normal. He achieved gaze changes in the vertical plane by combined blinks and head movements. Magnetic resonance imaging demonstrated bilateral lesions at the mesencephalic-diencephalic junction.

Adenosine is required for ethanol-induced heterologous desensitization

Recent evidence suggests that ethanol initially causes an increase in receptor-dependent cAMP levels, followed by heterologous desensitization of receptors coupled to GS after chronic exposure. Here we investigated the role of adenosine in mediating these responses. We found that ethanol caused accumulation of extracellular adenosine in NG108-15 and S49 lymphoma cells. This adenosine activated adenosine receptors to increase intracellular cAMP levels. The addition of adenosine deaminase, to degrade accumulated extracellular adenosine, or isobutyl-methylxanthine, an adenosine receptor antagonist, completely blocked ethanol-induced increases in cAMP levels in NG108-15 cells. Chronic exposure of NG108-15 and S49 wild type cells to ethanol resulted in heterologous desensitization of adenosine receptor- and prostaglandin E1 receptor-dependent cAMP signal transduction. Coincubation of NG108-15 and S49 wild type cells with adenosine deaminase and ethanol for 48 hr prevented heterologous desensitization. Moreover, mutant S49 cells, which are unable to transport adenosine, did not accumulate extracellular adenosine after incubation with ethanol and did not develop ethanol-induced heterologous desensitization. Our results suggest that adenosine is an important mediator of both the acute and chronic effects of ethanol on cAMP signal transduction.

Survival of recombinant erythropoietin in the circulation: the role of carbohydrates

Recombinant human erythropoietin produced in transfected Chinese hamster ovary cells is glycosylated much the same way as the erythropoietin present in human urine. To determine the role of carbohydrates in the stability of recombinant human erythropoietin in vivo, [125I]-labeled recombinant erythropoietin was intravenously infused into rats. The erythropoietin was slowly cleared from the blood with a half-life of approximately two hours. Asialoerythropoietin, which was produced by treatment of recombinant human erythropoietin with sialidase, was found to be cleared rapidly from circulation within ten minutes. These data suggest that the galactose binding protein of hepatic cells is involved in the clearance of asialoerythropoietin. Erythropoietin also contains N-glycans with a few N-acetyllactosamine repeats, which can be enriched by tomato lectin affinity chromatography. The lectin-bound fraction was cleared to a larger extent than was the unfractionated erythropoietin, while the component that did not bind the lectin was found to be stable in the circulation. Authentic N-acetyllactosamine repeats (polylactosaminoglycans) prepared from erythrocytes were similarly rapidly cleared from the circulation to the liver, and this clearance was inhibitable with asialo-alpha 1-acid glycoprotein. These results suggest that (a) the sialic acid of the recombinant erythropoietin is necessary for this glycoprotein hormone to circulate stably and (b) glycoproteins with more than three lactosaminyl repeat units may be cleared by the galactose binding protein of hepatocytes.

Effects of intravenous L-acetylcarnitine on retinal oscillatory potentials

L-acetylcarnitine is a compound with cholinergic properties and putative action on the visual system and the glucose metabolism. Ten healthy, emmertropic volunteers (age range: 21 to 28 years) were studied. Each subject was administered 5, 10, and 30 mg/kg acute intravenous doses of L-acetylcarnitine and matching placebo. Retinal oscillatory potentials to full-field flash stimulation were recorded before and 30, 60, and 120 min after administration. A systematic reduction of the implicit time of the P2 and N2 oscillatory potential components was observed after administration of the 10 and 30 mg/kg doses: significant changes were not evident at the 5 mg dose or after placebo. The latency reduction was significantly correlated with the postdrug increment of the L-acetylcarnitine plasma concentration. No other systematic modification in latency of amplitude was observed.

Effects of titrated beta blockade (metoprolol) on silent myocardial ischemia in ambulatory patients with coronary artery disease

This study investigates effects of beta-adrenergic blockade on total silent ischemic time assessed by ambulatory electrocardiographic monitoring and its relation to heart rate and time of day in ambulatory men with coronary artery disease. Metoprolol, when titrated to optimal dose in a controlled trial in 9 patients, reduced both total silent ischemic time (from 156 +/- 65 to 20 +/- 15 minutes, p = 0.04) and frequency of silent ischemic episodes (from 8 +/- 2 to 2 +/- 2 episodes, p = 0.03) compared with placebo. Mean daily heart rate was reduced, from 82 +/- 2 beats/min during placebo to 58 +/- 1 beats/min, as was heart rate at onset of 1 mm of ST-segment depression (106 +/- 2 to 74 +/- 4 beats/min, both p less than 0.001). Heart rate increased 10 +/- 1 beats/min during silent ischemia with placebo therapy, but increased only 4 +/- 1 beats/min during metoprolol treatment (p less than 0.03). During placebo administration the largest proportion of silent ischemic time occurred between 0600 and 1200 hours. Metoprolol attenuated this circadian variation in silent ischemia while reducing (p less than 0.05) total silent ischemic time in all periods. Thus, beta-adrenergic blockade reduces the frequency of silent myocardial ischemic episodes and total silent ischemic time, while mean daily heart rate and heart rate at onset of ischemia and maximal ischemia decrease. Metoprolol treatment also attenuates circadian variation of silent ischemia. These data may be interpreted to suggest that beta-adrenergic activation operates in the pathogenesis of silent myocardial ischemia and its circadian variation.

False-positive amniotic fluid acetylcholinesterase results: the need for a multifacet approach to the prenatal diagnosis of neural tube defects

Two cases are presented with false-positive amniotic fluid alpha-fetoprotein and acetylcholinesterase results for the prenatal diagnosis of neural tube defects. Stage II ultrasound revealed no lesions of the fetal spine in both cases. The alpha-fetoprotein and acetylcholinesterase results returned to normal on subsequent taps. Both pregnancies resulted in normal outcomes. A protocol is presented for managing pregnancies with abnormal alpha-fetoprotein and acetylcholinesterase results.

Platelet function and biosynthesis of prostacyclin and thromboxane A2 in whole blood after aspirin administration in human subjects

Small doses of aspirin have been shown to inhibit platelet thromboxane A2 while sparing vascular prostacyclin synthesis. Because leukocytes generate prostacyclin and participate in thrombosis along with platelets, the effects of three different doses of aspirin (40, 325 and 650 mg) on platelet function as well as on endogenous biosynthesis of thromboxane A2 and prostacyclin in whole blood were examined. In normal volunteers given a single 40 mg dose of aspirin, platelet aggregation and adenosine triphosphate release were inhibited for 24 hours. In contrast, platelet function was inhibited for 4 to 7 days in volunteers given 325 or 650 mg of aspirin. Platelet and whole blood generation of thromboxane A2 was inhibited less than 60% by the 40 mg dose, but almost completely by both the 325 and 650 mg doses. Likewise, whole blood generation of prostacyclin was inhibited 70% by the 40 mg dose and over 90% by the larger doses. Inhibition of thromboxane A2 as well as of prostacyclin was evident for 4 days with the 40 mg dose and for 7 days with the larger doses. Decreases in whole blood thromboxane A2 and prostacyclin with any dose of aspirin were of similar magnitude. These data indicate that aspirin in doses of 40 to 650 mg inhibits platelet function and biosynthesis of thromboxane A2 and prostacyclin in whole blood in human beings in a dose-dependent fashion.

Typhoid fever in San Antonio, Texas: an outbreak traced to a continuing source

Eighty cases of typhoid fever occurred in San Antonio, Texas, with dates of onset from August 18, 1981, to October 26, 1981. Preliminary epidemiological investigations of the first 24 cases suggested a Mexican food takeout restaurant as the common source. A case-control study confirmed this association (P less than or equal to .001). Barbacoa , a mixture of muscle, lips, ears, tongue, and eyes from steamed bovine heads, was identified as the source of Salmonella typhi (P = .03). S typhi was cultured from the stool of one of 31 restaurant employees. Closure of the restaurant resulted in termination of the outbreak within a single incubation period. The restaurant was allowed to reopen after the remaining employees had demonstrated lack of excretion of S typhi in stools. This outbreak represents the largest restaurant-associated typhoid fever outbreak reported in the United States in greater than 50 years.

Activation of cytotoxic T cells by nonstimulating tumor cells and spleen cell factor(s)

The ability of three cultured mouse tumor lines to stimulate a cytotoxic response in 5-day cultures of allogeneic lymph node cells was studied with a 51Cr release assay. Two lines of mesenchymal origin, P815 and EL-4, were found to be highly stimulatory, whereas the third cell line, CaD2, a mammary gland epithelial tumor, did not stimulate over a wide range of cell concentration. CaD2 cells were shown to contain major antigens similar to those of P815 cells by the specific lysis of both cells by lymphocytes activated to H-2d-bearing peritoneal cells.UV-irradiated P815-cells, like gamma-irradiated CaD2 cells, did not stimulate a cytotoxic response, but both cell lines were found to stimulate a full and specific response to allogeneic lymph node cells if these mixed cultures were supplemented with a supernatant harvested from concanavalin A-stimulated spleen cells.