Oblique hilar tomography and mediastinoscopy. A correlative prospective study in 100 patients with bronchogenic carcinoma

One hundred patients with bronchogenic carcinoma had oblique hilar tomography preoperatively to evaluate the pulmonary hila. Subsequently, all of these patients underwent mediastinoscopy or thoracotomy or both. Hilar and mediastinal nodes were evaluated for the presence of metastasis. These findings were then correlated with the radiographic findings of oblique hilar tomography. We found oblique hilar tomography to be a useful method of selecting patients for mediastinoscopy. The negative predictive value of oblique hilar tomography for mediastinal involvement was 95 percent, while the positive predictive value was 75 percent. Thus, patients with negative findings on oblique hilar tomography need not undergo mediastinoscopic examination prior to thoracotomy.

Sinus histiocytosis presenting as a mediastinal mass

A 32-year-old man with a ten-year history of bilateral cervical adenopathy, parotid gland swelling, and a posterior mediastinal mass, presented with headaches. A CAT scan of the head revealed a suprasellar mass. Craniotomy and biopsy of this lesion led to a diagnosis of sinus histiocytosis.

Potentiation of surfactant release in fetal lung by thyroid hormone action

Thyroid hormone has been shown to accelerate fetal lung development, but the mechanisms by which this hormone acts are yet unknown. Since this hormone may act indirectly by potentiating the action of endogenous catecholamines, we studied this mechanism by measuring beta-adrenergic receptors in fetal lung. Fetal rabbits at 27 days of gestation were treated with triiodothyronine (T3), 100 micrograms/100 g, in the presence and absence of propranolol, 200 micrograms/100 g, or actinomycin D, 20 micrograms/100 g. Fetuses were killed by decapitation either after 4 or 24 h of T3 treatment. The beta-adrenergic antagonist l-[3H]dihydroalprenolol was used to directly estimate the number and affinity of beta-adrenergic receptor in lung membranes. T3 increased the number of beta-adrenergic receptors in fetal lung, but the affinity of binding did not change. The enhancement of binding capacity after 4 h of T3 treatment was not inhibited by actinomycin D. However, 24-h T3-mediated stimulation was partially blocked by actinomycin D. In addition, T3 stimulated the catecholamine content, adenylate cyclase activity, and adenosine 3',5'-cyclic monophosphate content of lung. T3 increased the lecithin-to-sphingomyelin ratio, phosphatidylglycerol, and disaturated phosphatidylcholine content of the pulmonary lavage fluid. These parameters were completely inhibited by propranolol after 4 h and partially inhibited by actinomycin D after 24 h. Thus thyroid hormone enhances lung maturation by increasing the number of beta-adrenergic receptors in fetal lung.

A biphasic effect of chlordiazepoxide on animal locomotor activity

Centrally acting drugs often act 'biphasically', especially on animal locomotor activities: the same drug stimulates and depresses, depending either on dose or on time since administration. We propose a third, hitherto neglected, type of biphasic effect, well illustrated by chlordiazepoxide, which depends, instead, on the length of time an animal is exposed to a test environment: in an unfamiliar Y-maze, rats' spontaneous locomotion (number of entries into the arms of the Y) was stimulated to begin with, but switched to depression in a few minutes. The stimulant phase appeared to be independent of dose, while the depressant phase showed log linear dose dependence.

Fructose utilization by lung

We have examined the role of fructose as a substrate for the mammalian lung. Isolated and ventilated rat lungs were perfused for 2 h in the presence of either [U-14C]- or [5-3H]fructose. Fructose utilization, 3H2O production, and lactate and pyruvate production were measured. Insulin had no effect on the production of radiolabeled lactate. The 14C label from [U-14C]fructose was incorporated into the neutral lipids, phospholipids, fatty acid moiety, and deacylated fraction of lung. The apparent Km and maximum velocity of enzyme reaction for fructose utilization were 0.5 mM and 75 nmol X h-1 X g dry wt-1, respectively. Recovery of fructose 1-phosphate and fructose 1,6-diphosphate after perfusion with fructose, as well as detection of fructokinase, aldolase, and triokinase activities in the lung homogenates, suggested that fructose had been metabolized via phosphorylation through fructose 1-phosphate. Activities of fructose-metabolizing enzymes were not altered by the induction of diabetes, hypophysectomy, or starvation. These results suggest that mammalian lungs may utilize fructose to synthesize fatty acids, which in turn are used for phospholipid biosynthesis. The utilization of fructose by lung does not seem to be affected by nutritional or hormonal conditions.

Effect of starvation and diabetes on glucose transport in the lung

Transport of glucose by the isolated and perfused rat lung was studied using 2-deoxy-D-(1-14C)-glucose, 2-(1-14C)-DG, and 3-O-methyl-(U-14C)-glucose, 3-(U-14C)-MG. Uptake of 3-(U-14C)-MG was reduced by 20% in the lungs of fasting and diabetic rats, the uptake was restored by refeeding and insulin treatment, respectively. Although the intracellular accumulation of unphosphorylated 2-(1-14C)-DG in lungs was altered by a small amount in diabetes and fasting, the intracellular accumulation of phosphorylated 2-(1-14C)-DG was significantly reduced and restored by insulin treatment and refeeding, suggesting that phosphorylation was inhibited in these conditions. The reduction of glucose utilization in fasting or diabetic state was shown to be due to the inactivation of hexokinase II enzyme. Thus, a specific glucose-carrier system is present in the rat lung which appears to be insulin-sensitive and is under the nutritional and hormonal control.

Inhibition of differentiation and proliferation of colony-stimulating factor-induced clonal growth of normal human marrow cells in vitro by retinoic acid

Necessary for growth and differentiation in many normal tissues and capable of inducing differentiation in human promyelocytic cell lines, retinoids were the subject of this study. Specifically, effects of 13-cis-retinoic acid and 13-trans-retinoic acid on the growth of normal human bone marrow cells in soft-agar system were studied. Both short-term incubation and continuous exposure to retinoic acid caused a decreased number of granulocyte colonies and an increased cluster-to-colony ratio. This effect was concentration-dependent. Examination of specimens stained with Wright-Giemsa or nitro blue tetrazolium stains showed a progressive increase in the percentage of immature granulocytic precursors with increasing concentrations of retinoic acid. No effect of retinoic acid was seen on a number of human tumor cell lines. Retinoic acid blocked both differentiation and proliferation and appeared to do so by specific, noncytotoxic mechanisms in normal human bone marrow cells.

The effect of oxygen adaptation on oxyradical injury to pulmonary endothelium

Rats exposed to 85% O2 for 7 days develop an increase in pulmonary tissue levels of antioxidant enzymes and are able to survive subsequent exposure to 100% O2. In order to examine endothelial cell function in O2-adapted rats, we chemically generated oxygen radicals within the pulmonary circulation of lungs isolated from 85% O2-exposed rats and used [14C]5-hydroxytryptamine (5-HT) uptake as an indicator of endothelial cell function. The [14C]5-HT uptake in lungs of O2-exposed rats was similar to that in air-exposed rats and was reduced by cyanide, anoxia, and by imipramine. After generation of O2-derived free radicals within the pulmonary circulation, there was a progressive decline in [14C]5-HT uptake in both groups, with a more rapid decline seen in the lungs of air-exposed rats. These data suggest that pulmonary endothelial cells that survive 85% O2 exposure for 7 days are capable of normal function and are more resistant to further oxyradical injury.

The effect of oxygen-derived free radicals on pulmonary endothelial cell function in the isolated perfused rat lung

Oxygen-derived free radicals have been shown to damage endothelial cells in tissue culture. We have extended these observations to demonstrate a direct toxic action of oxy radicals on endothelial cell function in the isolated perfused rat lung model. Using an enzymatic system of hypoxanthine and xanthine oxidase, we generated a superoxide flux of 5-7 nmol/min within the pulmonary circulation. This resulted in alteration of endothelial cell function, including a progressive fall in the cellular transport of (14C) 5-hydroxytryptamine, edema formation manifested by a falling dry weight ratio and increasing mean transit times appearance of thiobarbituric acid reactive material in the perfusate indicating lipid peroxidation, and histologic evidence of edema formation with disruption of the endothelial cell plasma membrane. Inhibitor studies confirmed that the observed effects were due to superoxide radical generation. Oxygen derived free radicals may play a role in the pulmonary endothelial cell damages seen in inflammatory disorders and oxidant lung injury.

Effect of dexamethasone on the synthesis of dipalmitoyl phosphatidylcholine

Glucocorticoids are known to enhance surfactant production by stimulating the formation of phosphatidylcholine. This study was performed to determine the effect of steroids on one of the pathways involved in the incorporation of palmitic acid into phosphatidylcholine--the 'deacylation-reacylation pathway'. Palmitoyl CoA synthetase, lysopalmitoyl cholineacyltransferase and phospholipase A2 were enhanced significantly as a result of direct administration of dexamethasone into 27-day fetal rabbits. Cycloheximide inhibited the steroid induced enhancement of activity. Immunologic studies demonstrated an accelerated rate of synthesis of palmitoyl CoA as a result of the dexamethasone treatment. The data suggest that steroids are capable of inducing enzymes of the 'deacylation-reacylation pathway' involved in palmitate incorporation into phosphatidylcholine thereby contributing to the acceleration of dipalmitoyl phosphatidylcholine biosynthesis.

Supervision in liaison and consultation psychiatry

This paper reports special problems and techniques of teaching liaison and consultation psychiatry to psychiatric residents. It has become apparent that traditional methods of resident training are inadequate, and that specialized techniques of supervision are required to help the resident deal with the unique aspects of the liaison and consultation environment. Specific recommendations are made and discussed.

Imipramine normalizes naturally-occurring and drug-induced differences in the exploratory activity of rats

1 Exploratory activity of female hooded rats was measured in a Y maze on two occasions, 1 week apart. Locomotion (maze arm entries), rearing, and head-dipping into pots were scored for 5 min at each trial. 2 In control rats, differences between individuals in the amount of locomotion and rearing were consistent, as shown by significant test-retest correlations (r = +0.55, and +0.83 respectively). There was no correlation between head-dipping scores obtained in the two tests. 3 Imipramine (Imip) pretreatment before the second trial (10 mg/kg i.p on the 3 preceding days, and 2.5 mg/kg 1 h before) abolished these correlations. The scatter of the scores about the mean was also reduced by Imip, but there was no significant change in mean scores. Thus Imip appeared to have a 'normalizing' effect on locomotion and rears: after pretreatment, scores tended to be more uniform, and no longer reflected naturally-occurring individual differences. 4 Imip abolished the changes in exploratory activity produced by drugs which alter brain 5-hydroxytryptamine metabolism: p-chlorophenylalanine (100 mg/kg 24 h before testing) increased and DL-5-hydroxytryptophan (12.5 mg/kg 1 h before testing) decreased the fall in activity over the trial in saline-treated rats but not that in Imip-treated rats. In this case, Imip also produced an overall reduction in activity scores. 5 The normalizing effects of Imip on rat behaviour may be analogous to its therapeutic effects in human depressive disorders.

An analysis of physician resistance to psychiatric consultations

Although it has been estimated that between 30% and 60% of hospital patients have an emotional problem related to and sometimes affecting the course of their hospitalization, psychiatric consultations for such patients are rarely requested. We conducted chart rounds with house and nursing staffs to identify those patients with prominent psychiatric problems relating to hospitalization. It was found that physician resistance to consultation was involved in more than 50% of cases not referred, usually because the physicians believed that there was no psychiatric problem or that psychiatry could not help, and less often because the physician thought that the patient might become upset or the patient-doctor relationship would be destroyed. The basis of the physicians' resistance was found not justified in 26 of 29 patients seen, and 23 of these patients were judged to have been helped by the psychiatrist.

Competition between platelets and lung for 5-hydroxytryptamine uptake

The pulmonary endothelial cell removes 5-5-hydroxytryptamine (5-HT) from the circulation by a process of uptake and metabolism. The platelet, the major source of 5-HT in the circulation, represents another potential site of uptake for this amine. Platelet uptake of 5-HT infused into the pulmonary circulation was evaluated using isolated ventilated rat lungs. Lungs were perfused with buffer, platelet-poor, platelet-rich, or thrombin-treated platelet-rich plasma followed by an infusion of (14C) 5-HT. Platelet counts, aggregation response to adenosine diphosphate, and in vitro uptake of 55-HT were unchanged after circulation through the lung. In the presence of buffer or platelet-poor plasma, the lung removed 65.5 +/- 1.4% and 67.8 +/- 0.8%, respectively, of the infused (14C) 5-HT. In the presence of platelet-rich plasma, the lung removed 51.3 +/- 3.0 and platelet fraction 30.1 +/- 1.4% of the infused (14C) 5-HT. Recently aggregated platelets removed 24.4 +/- 1.8%, whereas platelets exposed to low oxyygen tensions removed 14.7+/- 0.6% of the (14C) 5-HT. These results indicate that 5-HT released inot the pulmonary circulation is either taken up by the endothelium and metabolized or taken back up by the platelet and stored.

Acute hydrogen selenide inhalation

Acute exposure to selenium hydrochloride resulted in severe dyspnea and a pneumomediastinum in a young healthy man. Pulmonary function tests revealed restrictive and obstructive airways disease. Although the patient's pulmonary function slowly improved, subsequent studies revealed persistent impairment. Therefore, exposure to selenium gas may result acutely in severe coughing and wheezing and may lead to irreversible obstructive lung disease.

Reversal of 2-deoxyglucose inhibition of serotonin uptake in isolated guinea pig lung

The effect of various substrates on the rate of uptake of 5-hydroxytryptamine (serotonin) from the pulmonary circulation was studied with isolated guinea pig lungs. Lungs were ventilated and were perfused with an electrolyte solution in a recirculating system. Uptake of serotonin was calculated from the rate of disappearance of [14C]serotonin from the perfusate. Serotonin uptake was inhibited by approximately 40% when 5 mM 2-deoxyglucose was substituted for glucose in the pulmonary perfusate. The inhibition due to 2-deoxyglucose was reversed by addition to the perfusate of pyruvate, lactate, acetate, alanine, beta-hydroxybutyrate, palmitate, or glycerol. Fructose ans succinate were less efficient substrates while no significant effect was noted with L-glycerol 1-phosphate or L-phenylalanine. These results indicate that a wide variety of metabolizable substrates can be utilized by the pulmonary endothelium to support uptake of serotonin.

Effects of delta9-tetrahydrocannabinol on social behaviour in mice: comparison between two vehicles

Two vehicles for the intraperitoneal administration of delta9-tetrahydrocannabinol (delta9-THC) were compared, using aspects of social behaviour in mice and 5 doses of delta9- THC, with vehicle alone and saline control groups. 10% propane-1,2-diol-1% Tween 80-saline (vehicle B) seemed to be more effective than 1% Tween 80-saline (vehicle A) since depressant effects of --1 delta9-THC on behaviour tended to occur at lower doses with this vehicle. Few differences in behaviour could be detected among the three control groups. In general the overall number of behavioural acts decreased with increasing doses of delta9-THC, but with vehicle B low doses selectively decreased the number of 'social' (including aggressive) as distinct from 'individual' acts. Low doses of the drug in vehicle A sometimes stimulated behaviour, whereas with vehicle B such doses mostly produced depression; however, 2.5 mg/kg delta9-THC, in either vehicle, markedly increased the percentage of animals which showed both aggression and flight acts--a rare combination among controls. Our findings are consistent with other evidence that propylene glycol is an effective vehicle for the i.p. administration of delta9-THC.

Depression of pulmonary 5-hydroxytryptamine uptake by metabolic inhibitors

Energy requirements for uptake of 14-C labeled 5-hydroxytryptamine ([14-C]5-HT) were studied in isolated guinea pig lungs, ventilated with 95% O2-5% CO2 and perfused in a recirculating system with Krebs-Ringer-bicarbonate solution containing 4% bovine serum albumin and 5 mM glucose. After 14 min preincubation with various inhibitors, lungs were perfused for 30 min with 0.25 times 10- minus 6 M [14-C]5-HT. Aliquots of perfusate were analyzed for [14-C]5-HT and metabolic products. Control lungs had a fractional serotonin clearance of 0.57 plus or minus 0.04. The rate of removal of [14-C]5-HT was inhibited 96% by imipramine, 88% by chlorpromazine, and 65% by ouabain, but was unaffected by iproniazid. Anoxia and cyanide each inhibited uptake by 68%. Omitting glucose from the perfusate reduced uptake by 30%. 2-Deoxyglucose and iodoacetate decreased the rate of [14-C]5-HT removal by 44 and 70%, respectively. Uptake was not affected by lung weight gain nor by changes in lung mechanical properties produced by [14-C]5-HT. [14-C]5-HT uptake by guinea pig lung requires a metabolic source of energy providing additional evidence for transport by an active process.