Evaluation of a leukotriene receptor antagonist in prevention of hyperoxic lung injury in newborn rabbits

Prolonged exposure to hyperoxia can result in significant lung injury and has been associated with the development of bronchopulmonary dysplasia. Leukotrienes (LT) recruit polymorphonuclear leukocytes (PMN) to the lung, increase vascular permeability, and have therefore been postulated to play a role in the pathogenesis of hyperoxic lung injury. This study investigates ICI 198,615 (ICI), an LTD4 and LTE4 receptor antagonist in preventing hyperoxic lung injury in newborn rabbits. Matched littermates of 7-day-old rabbits received ICI (0.1 or 1.0 microM/kg/h) or vehicle alone, were exposed to greater than 95% O2, and sacrificed after 48, 72, 84 and 96 h of exposure. Bronchoalveolar alveolar lavage fluid (BAL) of the left lung was analyzed for white cell count, differential, absolute number of PMNs, total protein, and cyclooxygenase products 6-keto-PGF1 alpha, and thromboxane B2. Lung water was quantified utilizing the right lung. Results demonstrated no significant differences between the ICI groups or between the ICI groups and controls. In conclusion, the administration of the LTD4 and LTE4 receptor antagonist ICI 198,615 was insufficient to reduce the formation of pulmonary edema, reduce mortality or attenuate hyperoxic lung injury. These experiments suggest that a number of other mediators may be involved in the hyperoxic lung injury process and that the functional inhibition of a portion of the arachidonic acid cascade was not sufficient to either prevent or attenuate hyperoxic lung injury in newborn rabbits.

Season of birth of siblings of schizophrenic patients

The hypothesis that mothers of winter-spring-born schizophrenics have an unusual pattern of conception which results in an excess of winter-spring births was tested by studying the distribution of birth-dates of 401 siblings of 120 winter-spring-born schizophrenics and 157 siblings of 59 winter-spring-born controls. All analyses were gender-specific. The results suggest there is no association between the probability of a winter-spring date of birth and being a sibling of a winter-spring-born schizophrenic or control.

Risk factors in schizophrenia. Season of birth, gender, and familial risk

The risk for schizophrenia among first-degree relatives of schizophrenic probands obtained from an epidemiological sample using family history methods was examined to determine whether month of birth of the proband was associated with familial risk. The results of this study of the first-degree relatives of 106 female schizophrenics and 275 male schizophrenics suggested that the relatives of probands born in the months February to May had the highest risk, although the association between month of birth and familial risk among the male probands was present only for those relatives who had onset of schizophrenia before the age of 30.

Anticardiolipin antibody-positive serum enhances endothelial cell platelet-activating factor production

Circulating antiphospholipids have been linked to recurrent pregnancy loss by a mechanism involving placental and decidual thrombosis. We hypothesized that platelet-activating factor, an autacoid synthesized by vascular endothelium, might mediate this phenomenon through its ability to promote platelet aggregation and fibrin deposition. Alternatively, antiphospholipid antibodies might exert a procoagulant effect by inhibiting the synthesis of prostacyclin. To evaluate these theories, endothelial cells (harvested from human umbilical veins) were grown to confluence and incubated for 48 hours with 20% concentrations of anticardiolipin antibody-positive and -negative human sera as well as fetal bovine serum. After incubation culture wells were stimulated with 10 mumol/ml calcium ionophore A23187 (an agonist of platelet-activating factor and prostacyclin synthesis). Intracellular platelet-activating factor was measured by tritiated acetate incorporation, phospholipid extraction, thin-layer chromatography, and scintillation spectrophotometry. Enhanced platelet-activating factor synthesis was identified in cultures incubated with anticardiolipin antibody-positive serum (25,544 +/- 2604 disintegrations per minute, mean +/- SD) when compared with anticardiolipin antibody-negative serum (18,600 +/- 3316 dpm) or fetal bovine serum (19,014 +/- 4233 dpm; analysis of variance, p = 0.033). In similar experiments, prostacyclin synthesis was determined by measuring its primary metabolite, 6-keto-prostaglandin F1 alpha, in culture supernatants. No differences between anticardiolipin antibody-positive and control cultures were observed (analysis of variance, p = 0.90). We conclude that in this endothelial cell model, anticardiolipin antibody-positive serum enhances ionophore-mediated platelet-activating factor synthesis but has no apparent effect on the production of prostacyclin. These findings suggest a potential role for platelet-activating factor in anticardiolipin antibody-mediated vascular thrombosis.

[Validity of the Beck Depression Inventory for cross-cultural comparisons. A study of German and Egyptian patients]

The present study compares self-rated depressive symptoms of 95 inpatients with depressive syndromes: 45 in Germany and 50 in Egypt. In each country, 50 patients suffering from acute internal diseases served as controls. Psychiatric patients were selected according to DSM-III criteria for major depressive disorder (MDD). Depressive symptoms and depth of depression were scored by the Beck Depression Inventory (BDI). The self-rating of depressive symptoms proved sufficient for transcultural comparison, provided controls are used, and was more practicable than observer rating scales. The results indicate higher BDI total scores for Egyptian than for German inpatients. This appear to be due to cultural differences, presumably mostly in language performance ("tendency to hyperbole"). Moreover, Egyptians complained more about somatic symptoms, as has already been frequently suggested on the basis of clinical observations.

The secretory S complex in Bacillus subtilis is identified as pyruvate dehydrogenase

We have cloned the operon for the Bacillus subtilis S complex, which has been suggested to be a component of the protein secretion machinery. The S-complex operon was found to encode 4 proteins, which were identified as subunits of pyruvate dehydrogenase (PDH). The Staphylococcus aureus membrane-bound ribosome protein (MBRP) complex has been considered to be a counterpart of the B. subtilis S complex. Here, we sequenced a fragment of the MBRP operon encoding the C-terminal part of E1 beta, the entire E2 and the N-terminal part of the E3 subunit of PDH, thus conclusively confirming the PDH identity of the MBRP complex as well. It appeared unlikely that PDH could be a primary component in protein secretion, thus disproving the previous hypothesis of the role of the S complex. However, attachment of the S complex (PDH) to the membrane and ribosomes may produce a biologically significant interaction.

Osmoregulation in Saccharomyces cerevisiae. Studies on the osmotic induction of glycerol production and glycerol-3-phosphate dehydrogenase (NAD+)

Production of glycerol and a key enzyme in glycerol production, glycerol 3-phosphate dehydrogenase (NAD+) (GPD), was studied in Saccharomyces cerevisiae cultured in basal media or media of high salinity, with glucose, raffinose or ethanol as the sole carbon source. At high salinity, glycerol production was stimulated with all carbon sources and glycerol was accumulated to high intracellular concentration in cells grown on glucose and raffinose. Cells grown on ethanol accumulated glycerol to a lower level but showed an increased content of trehalose at high salinity. However, the trehalose concentration corresponded only to about 20% of the glycerol level, and did not compensate for the shortfall in intracellular osmolyte content. Immunoblot analysis demonstrated an increased production of GPD at high salinity. This increase was osmotically mediated but was lower when glycerol was substituted for NaCl or sorbitol as the stress-solute. The enzyme also appeared to be subject to glucose repression; the specific activity of GPD was significantly lower in cells grown on glucose, than on raffinose or ethanol.

Schizophrenia: age at onset, gender and familial risk

In a family history study of 366 schizophrenic probands and their 1851 first-degree relatives, we found a relationship between age at onset of psychosis in the male probands and the risk for schizophrenia in their relatives. The relatives of male schizophrenic probands whose onset of psychosis occurred when they were younger than 17 years of age had an increased risk of schizophrenia when compared with the relatives of male probands with an age at onset greater than 17. We did not find an association between age at onset of psychosis in the female probands and familial risk. Cox proportional hazards models permitted us to examine the relationship between age at onset of psychosis in the probands and familial risk while controlling for possible confounding effects.

Afferent information processing in patients with chronic alcoholism. An evoked potential study

Visual evoked potentials (VEP), median nerve sensory conduction velocity (SNCV) as well as sensory evoked potentials (SEP), and brainstem acoustic evoked potentials (BAEP) were investigated on both sides in 40 patients with chronic alcoholism (mean age 37 years) without clinical signs of alcohol-induced central nervous system lesions. The results were compared to those obtained in 40 normal controls (mean age 32 years). In both groups, the parameters were analysed by means of both dependence and interdependence statistics. Dependence statistics (ANOVA) revealed significant differences between both groups. In 70% of the patients, at least one pathological parameter (greater than mean +/- 2.5 SD) was found; about 38% of the patients had two or more pathological values. Most pathological parameters were observed with BAEP testing (45% of patients) followed by SNCV (33%), median nerve SEP (30%), and VEP (10%). No significant clustering of pathological parameters was found in certain patients. By means of interdependence statistics, evidence is presented for a disturbance of sensory processing in the brainstem auditory pathways of the patients.

Purification and characterization of glycerol-3-phosphate dehydrogenase (NAD+) in the salt-tolerant yeast Debaryomyces hansenii

The NAD-dependent glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) of the salt-tolerant yeast Debaryomyces hansenii was purified by poly(ethylene glycol) precipitation and a combination of chromatographic procedures. The enzyme existed in two forms with different ionic characters and specific activity. On SDS-polyacrylamide gel electrophoresis, both forms yielded one predominant band with an apparent molecular weight of 42,000. The specific activity of the enzyme was dependent on the concentration of the enzyme and on the ionic strength of the dissolving medium. All ions tested stimulated the enzyme activity in the ionic strength range 0-100 mM, with glutamate yielding the highest activity. Above these concentrations, the dehydrogenase showed high tolerance for glutamate in concentrations up to 0.9 M, whereas malate, sulfate and chloride were inhibitory. Enzyme activity showed little sensitivity to the type of cation present and was only slightly affected by 5 M glycerol. The true Km values for the substrates were 6.6 microM for NADH, 130 microM for dihydroxyacetone phosphate, 0.3 mM for NAD and 1.2 mM for glycerol-3-phosphate, and the enzyme showed specificity for these four substrates only. It is proposed that the enzyme functions in cellular osmoregulation by providing glycerol 3-phosphate for the biosynthesis of glycerol, the main compatible solute in D. hansenii, and that the enzyme is well adapted to function in yeast cells exposed to osmotic stress.

A procedure for enrichment and isolation of mutants of the salt-tolerant yeast Debaryomyces hansenii having altered glycerol metabolism

The salt-tolerant yeast Debaryomyces hansenii produces and accumulates glycerol when subjected to salt stress, whereby the buoyant density of the cells is changed. This property allows for enrichment of mutants with altered glycerol metabolism by density gradient centrifugation. Colonies derived from cells with rapidly changing density following an osmotic shock were screened for increased glycerol production by observing their ability to support growth of a glycerol-requiring strain of Escherichia coli. The glycerol overproducting phenotype of two isolates was confirmed by chemical analysis.

Osmoregulation of the salt-tolerant yeast Debaryomyces hansenii grown in a chemostat at different salinities

The intracellular solute composition of the salt-tolerant yeast Debaryomyces hansenii was studied in glucose-limited chemostat cultures at different concentrations of NaCl (4 mM, 0.68 M, and 1.35 M). A strong positive correlation between the total intracellular polyol concentration (glycerol and arabinitol) and medium salinity was demonstrated. The intracellular polyol concentration was sufficient to balance about 75% of the osmotic pressure of the medium in cultures with 0.68 and 1.35 M NaCl. The intracellular concentration of K+ and Na+, which at low external salinity gave a considerable contribution to the intracellular water potential, was only slightly enhanced with raised medium salinity. However, the ratio of intracellular K+ to Na+ decreased; but this decrease was less drastic in the cells than in the surrounding medium, i.e., the cells were able to select for K+ in favor of Na+. The turgor pressure, which was estimated on the basis of intracellular solute concentrations, was 2,200 kPa in cultures with 4 mM NaCl and decreased when the external salinity was raised, resulting in a value of about 500 kPa in cultures with 1.35 M NaCl. The maintenance of a positive turgor pressure at high salinity was mainly due to an increased production and accumulation of glycerol.

In vivo ultrasound arterial recanalization of atherosclerotic total occlusions

The purpose of this study was to assess the potential of intraarterial ultrasound for in vivo recanalization of atherosclerotic total occlusions. Ultrasound energy at a frequency of 20 kHz was applied with a prototype solid wire probe to 12 surgically implanted occluded human atherosclerotic arterial xenografts, 9 of which were calcified, as well as to the intimal surface of 12 normal canine arteries. In both the normal canine arteries and the atherosclerotic occluded xenografts, there was no angiographic evidence of vasospasm, thrombosis or arterial dissection. Eleven of the 12 atherosclerotic complete arterial occlusions were resistant to passage of a conventional guide wire or probe without ultrasound energy. However, the occlusions were recanalized after administration of 15 s to 4 min (mean 1.5 +/- 1.3 min) of intermittent ultrasound energy. After ultrasound, 8 of the 12 vessels underwent balloon angioplasty. Angiographic residual stenosis after ultrasound alone was 62 +/- 24% and after combined ultrasound and balloon angioplasty, 29 +/- 13%. Although routine angiography did not reveal arterial emboli, high resolution cut films did demonstrate a few distal nonocclusive thrombi of a size similar to that reported with other recanalization methods. Histologic studies demonstrated changes similar to those after balloon angioplasty, with focal cracking of the fibrotic and calcified plaque. The findings demonstrate that ultrasound energy applied through a catheter delivery system can be used in vivo to open completely obstructed atherosclerotic vessels. These studies suggest that it might be clinically feasible to use the ultrasound probe to create a lumen, allowing subsequent balloon dilation.

Efficacy of low-dose metoprolol in neuroleptic-induced akathisia

Recent studies have shown that the beta-blockers can be effective treatments for neuroleptic-induced akathisia. However, the relative contributions of beta-1 versus beta-2 blockade to the therapeutic effect of beta-blockers remains unclear. We treated nine patients who had neuroleptic-induced akathisia with low doses (25-100 mg/day) of the beta-blocker metoprolol. At these doses metoprolol causes selective blockade of beta-1 receptors. Seven patients improved after metoprolol; no further substantial changes were seen after subsequent treatment with propranolol. This finding suggests that neuroleptic-induced akathisia can be improved by selective beta-1 blockade.

Percutaneous excimer-laser and excimer-laser-assisted angioplasty of the lower extremities: results of initial clinical trial

Percutaneous peripheral excimer-laser angioplasty at 308 nm was used for treatment of 30 patients with peripheral vascular disease. Twenty-eight patients underwent laser-assisted balloon angioplasty, and two patients underwent laser angioplasty alone. Acute angiographic and clinical success was achieved in 24 of 31 (77%) femoropopliteal stenoses and occlusions. Seven of nine (78%) stenoses, six of seven (86%) short (0-5 cm) occlusions, seven of eight (88%) medium-length (6-10 cm) occlusions, three of four (75%) long (11-15 cm) occlusions, and one of three (33%) extreme (greater than 15 cm) occlusions were successfully treated. Inability to treat total occlusions was in each case related to a failure to maintain coaxial position and subintimal passage of the fiber. These cases demonstrate the feasibility of safely performing percutaneous peripheral excimer-laser or excimer-laser-assisted angioplasty. The overall frequency of restenosis after a mean follow-up period of 9.1 months was 29%. The data suggest that these procedures may be useful for the treatment of peripheral vascular disease in selected patients.

Increased platelet intracellular calcium concentration in patients with bipolar affective disorders

Using the fluorescent indicator Fura 2, we measured the free intracellular calcium ion concentration in blood platelets of patients with untreated mania, bipolar depression, and unipolar depression; patients who had recovered from bipolar depression or mania; and age- and sex-matched controls. The baseline intracellular calcium ion concentration was significantly increased in platelets from patients with mania compared with controls. The free intracellular calcium ion concentration after stimulation with platelet-activating factor and thrombin was significantly higher in platelets of manic and bipolar depressed patients than in all other groups. The degree to which intracellular calcium ion concentration increased over baseline after stimulation was significantly lower in unipolar than in bipolar patients. These findings suggest that platelets of manic and depressed bipolar patients have a similar enhancement of intracellular calcium ion activity that is distinctly different from the decreased ability of platelets of unipolar patients to mobilize intracellular calcium in response to stimulation.

Role of eicosanoids in relative oxygen tolerance of newborn rabbits

Prolonged exposure to hyperoxia can result in significant lung injury, although newborn animals are more oxygen-tolerant than adults. Mechanisms affording tolerance to the newborn are incompletely understood. This study examined the hypothesis that eicosanoids play a significant role in newborn oxygen tolerance. One litter of term newborn albino rabbits and 15 adult rabbits were exposed to 65 hours of greater than 95% O2. An additional litter of newborns served as a normoxic control. Normoxic newborn rabbits had very high quantities of 6-keto-PGF1a and low TXB2 in bronchoalveolar lavage (BAL) fluid. Sixty-five hours of oxygen exposure in newborn rabbits produced no evidence of lung injury on light microscopy, 97% of BAL white cells were alveolar macrophages and BAL protein was low. An equal period of oxygen exposure produced significant lung injury in adult rabbits. BAL fluid from oxygen-injured adults contained a 17-fold greater percentage of PMN and 16-fold higher protein than oxygen-exposed newborns. Hyperoxic adults had significantly lower 6-keto-PGF1a, and significantly higher LTB4 and LTC4 in BAL compared to hyperoxic newborns. This study confirms the hypothesis of relative oxygen tolerance in newborn rabbits compared to adults, and suggests that this tolerance may have been afforded by higher pulmonary levels of the protective prostacyclin metabolite.

Roles of glycerol and glycerol-3-phosphate dehydrogenase (NAD+) in acquired osmotolerance of Saccharomyces cerevisiae

In a cell culture of Saccharomyces cerevisiae exponentially growing in basal medium, only 0.02% of the cells were osmotolerant, i.e., survived transfer to medium containing 1.4 M NaCl. Short-time conditioning in 0.7 M NaCl medium transformed the whole population into an osmotolerance phenotype. During this conditioning, the rate of formation of glycerol, the main compatible solute in S. cerevisiae, increased threefold and the specific activity of glycerol-3-phosphate dehydrogenase (NAD+) (GPDH) (EC 1.1.1.8) was enhanced sixfold. The apparent flux control coefficient for GPDH in the formation of glycerol was estimated to be 0.6. Glycerol production was also favored by regulated activities of alcohol dehydrogenase (EC 1.1.1.1) and aldehyde dehydrogenase [NAD(P)]+ (EC 1.2.1.5). About 50% of the total glycerol produced during conditioning in 0.7 M NaCl was retained intracellularly, and the increased glycerol accumulation was shown to be not merely a result of enhanced production rate but also of increased retention of glycerol. Washing the cells with solutions of lower salinities resulted in loss of glycerol, with retained levels proportional to the concentration of NaCl in the washing solution. Cycloheximide addition inhibited the development of acquired osmotolerance and conditioned cells washed free of glycerol retained a high degree of osmotolerance, which indicate that protein synthesis was required to establish the osmotolerance state.

Loss of oxygen tolerance in newborn rabbits: relationship to changes in eicosanoid and antioxidant levels

Relative tolerance of newborn animals to hyperoxia has been reported. This study investigated the age limitation of oxygen tolerance and mechanisms for its loss. Developmental changes in lungs of normoxic New Zealand rabbits were studied on days 1, 3, 4, 5, and 10 of life. These were contrasted with newborn and 7-day-old rabbits exposed to greater than 95% O2 for 65 hours. Normoxic rabbits demonstrated a decrement in bronchoalveolar lavage (BAL) 6keto-PGF1a, thromboxane B2, and lower lung catalase, total glutathione, and superoxide dismutase with maturation. Newborns were more tolerant to oxygen than 7-day-old rabbits. Oxygen exposure beginning on day 1 did not result in identifiable lung damage. Exposure beginning on day 7 resulted in microscopic evidence of injury and significant increases in BAL white cells, neutrophils and protein, and a trend toward higher BAL LTB4 compared to normoxic age-matched controls. Antioxidants were higher in the hyperoxic 7 day-olds, but remained lower than values in hyperoxic newborns. These results suggest that loss of oxygen tolerance in maturing rabbits is related to a developmental decrement in antioxidants and prostacyclin.

Effects of verapamil on tardive dyskinesia and psychosis in schizophrenic patients

Nine hospitalized schizophrenic patients with tardive dyskinesia were treated with the calcium-channel antagonist verapamil under single-blind conditions. The tardive dyskinesia and activation scores decreased, and the anxiety/depression scores increased. The changes were small but statistically significant.