Influence of lesions of the noradrenergic locus coeruleus system on the cerebral metabolic response to bicuculline-induced seizures

The objective of the present study was to explore if lesions of the ascending noradrenergic pathways, originating in the locus coeruleus, modulate the cerebral metabolic response to bicuculline-induced seizures in rats. Bilateral noradrenergic lesions were performed by 6-hydroxydopamine injections in the caudal mesencephalon, 12–22 days before seizures were induced in animals ventilated on N₂O:O₂ (75:25). After 5 min of seizures the brain was frozen in situ and cerebral cortex and hippocampus were sampled for analysis. Labile phosphates, glycolytic metabolites, cyclic nucleotides, and free fatty acids were measured. In another series, lesioned animals were used for measurements of cerebral oxygen consumption.The noradrenergic lesions neither modified the electroencephalographically recorded seizure discharge, nor did they alter cerebral oxygen consumption or cerebral energy state. However, when compared to sham-operated animals, those with noradrenergic lesions had significantly higher (115% and 68%) glycogen concentrations and lower (50% and 52%) cyclic AMP concentrations in cerebral cortex and hippocampus, respectively, demonstrating the marked influence of noradrenergic activity on adenylate cyclase activity and glycogenolysis. The lesions failed to modulate the rise in free fatty acids in the cerebral cortex, or the cyclic GMP concentrations in the cerebral cortex and hippocampus. Thus, increased noradrenergic activity during status epilepticus does not seem responsible for lipolysis or for activation of guanylate cyclase.     

Malignant lymphoma and exposure to chemicals, especially organic solvents, chlorophenols and phenoxy acids: a case-control study.

A number of men with malignant lymphoma of the histiocytic type and previous exposure to phenoxy acids or chlorophenols were observed and reported in 1979. A matched case-control study has therefore been performed with cases of malignant lymphoma (Hodgkin''s disease and non-Hodgkin lymphoma). This study included 169 cases and 338 controls. The results indicate that exposure to phenoxy acids, chlorophenols, and organic solvents may be a causative factor in malignant lymphoma. Combined exposure of these chemicals seemed to increase the risk. Exposure to various other agents was not obviously different in cases and in controls.     

Structural properties of the covalent (+)-anti-BPDE-poly(dG-dC)(dG-dC) complex

The structure of the covalent (+)-anti-BPDE-poly(dG-dC) complex can be represented by two preferred orientations of the pyrene moiety; one at about 20 degrees relative to the helix axis and one at about 70 degrees, populated as 4:1. A rapid mobility of the BPDE may allow an exchange between the two orientations. The poly(dG-dC) structure becomes more flexible by (+)-anti-BPDE modification, seen as a shortened persistence length. This complex may be significant as a model for DNA interaction with covalently binding polyaromatic carcinogens.     

Nonlinear systems analysis of the hippocampal perforant path-dentate projection. I. Theoretical and interpretational considerations

1. Nonlinear systems analytic procedures, based on an orthogonalized functional power series approach, were developed for study of the transformational properties of the hippocampal formation. As a testing stimulus, the procedures utilize a train of electrical impulses with randomly varying interimpulse intervals. The specific case was considered of applying such a stimulus to the perforant path, a major afferent to the hippocampal dentate gyrus that arises from the entorhinal cortex. Resulting field potentials evoked within the dentate gyrus are recorded to all impulses in the train. Computational algorithms based on cross-correlations determine the relationship between the interimpulse interval within the random train and amplitude of the evoked dentate potentials. The calculations, which reduce to averaging procedures, were derived for first- and second-order terms, or kernels, of the orthogonalized functional power series. 2. It is proposed that such an approach can be applied to a single component of the complex field potential evoked in the dentate gyrus. This component, the population spike, reflects the action potential discharge of dentate granule cells. Thus, a field potential component for which the underlying neuronal generator is well-known can be analyzed with respect to the transformational characteristics of the network of neurons that influence that generator. Other components of the complex field potential produced by other generators can be ignored. It is shown that this adaptation has the effect of greatly simplifying both the computation and presentation of kernels. 3. As a further consequence of this adaptation, the resulting first- and second-order kernels were shown to have specific interpretations. The first-order kernel represents the average response of the orthodromically driven granule cells to the set of stimuli comprising the random impulse train. The second-order kernel quantitatively characterizes the nonlinearity of the granule cell response, and may be interpreted as a generalized recovery function; i.e., the first input of any pair of stimuli in the train activates the newtork, and the second input tests the modulatory influence of the network excited by the initial input. 4. Most past investigations of nonlinearities of the perforant path-dentate projection have utilized pairs of stimulus impulses. We show here that, for a second-order system, the expected results from paired impulse experiments may be predicted from second-order kernels. Disagreement between the measured and predicted results reflects interactions of a higher order, and thus, greater system complexity.(ABSTRACT TRUNCATED AT 400 WORDS)     

High-Frequency Positive-Pressure Ventilation (HFPPV) During Transthoracic Resection of Tracheal Stenosis and During Peroperative Bronchoscopic Examination

Operation of a patient with intrathoracic tracheal stenosis using a new ventilation technique (HFPPV) is described. The technique permits tracheoscopy during ventilation and operation, thus enabling exact location of the stenosis to be obtained. Further, peroperative tracheoscopic checking of the anastomosis can be carried out. Resection and anastomosis can be performed without interference of a bulky endotracheal tube.  

ZUSAMMENFASSUNG

Es wird die Operation eines Patienten mit intrathorakaler Trachealstenose beschrieben, bei der eine neue Beatmungstechnik (HFPPV = hochfrequente Überdruck-Ventilation) angewandt wurde. Die Methode ermöglicht unter gleichzeitiger Beatmung eine tracheoskopische genaue Lokalisation der Stenose. Ferner kann während der Operation die Anastomose tracheoskopisch kontrolliert werden. Resektion und Anastomose können ohne Beeinträchtigung durch einen dicken Endotrachealtubus vorgenommen werden.     

Treatment of craniopharyngiomas — the stereotactic approach in a ten to twenty-three years' perspective

Summary A multi-modality treatment programme, where stereotactic methods were used preferentially, gave results in a consecutive series of craniopharyngiomas, not inferior to those reported after microsurgical removal. Fourty-two patients with a follow-up range of 10–23 years are reported.     

Plexiform fibrohistiocytic tumor. Report of a case involving preoperative aspiration cytology and immunohistochemical and ultrastructural analysis of surgical specimens.

A typical case of plexiform fibrohistiocytic tumor (Enzinger and Zhang) occurring in the skin and subcutis of the abdominal wall in a 7-year-old girl is reported. Preoperative fine-needle aspiration cytology revealed a benign lesion with fibroblastic-histiocytic features which also contained bi- and multinucleated giant cells. The surgical specimen showed a tumor with multiple small nodules within fibrous septa; these nodules were composed of spindle cells and epithelioid cells and contained scattered multinucleated osteoclast-like cells. The tumor cells showed ultrastructural and immunohistochemical features of myofibroblasts and histiocyte-like cells. Thus, there was an abundance of lysosomes, prominent filopodia and bundles of thin cytofilaments along the cytoplasmic border, as well as immunoreactivity for alpha-smooth-muscle-specific actin, alpha-1-antitrypsin and alpha-1-antichymotrypsin. Ultrastructurally there were tumor cells exhibiting features of histiocytes which also contained bundles of actin of smooth muscle type. The presented case of plexiform fibrohistiocytic tumor appears to be composed of a rather peculiar cell form, somewhere between myofibroblasts and histiocytes.     

Effects of chronic beta-adrenoceptor antagonism on plasma catecholamines and blood pressure in hypertension

Plasma catecholamines were measured before and after treatment with beta-adrenoceptor antagonists in 17 hypertensive patients. Chronic treatment with beta-adrenoceptor antagonists caused substantial reductions in heart rate and intra-arterial blood pressure recorded continuously during ambulation. Before treatment, a quantitative relationship was observed between plasma norepinephrine and blood pressure and heart rate during a variety of activities; a similar relationship was also observed after chronic treatment five of six patients, suggesting that plasma norepinephrine remains an index of sympathetic activity despite the influence of beta-adrenoceptor antagonism. After treatment, plasma norepinephrine tended to be higher at any level of blood pressure, although not significantly so. Chronic treatment caused no significant change in mean resting plasma levels of norepinephrine and epinephrine. During exercise, plasma norepinephrine and epinephrine levels were significantly elevated above control after acute but not after chronic treatment. These observations do not support the hypothesis that beta-adrenoceptor antagonist drugs lower blood pressure in hypertensive man through a sympatholytic mechanism in he central nervous system or at peripheral presynaptic receptors.     

Synthesis and antiviral activity of distamycin A analogues: substitutions on the different pyrrole nitrogens and in the amidine function

Several new analogues of the antiviral antibiotic distamycin A were synthesized and assayed for their effects on influenza and herpes simplex virus. The new compounds 5b-j (R1-3 = H, CH3, and C2H5, R4,5 = H and CH3) were obtained via stepwise prepared formylated trimeric benzyl 4-aminopyrrole-2-carboxylates 3a-h, which after catalytic hydrogenolysis were coupled as N-succinimidyl esters directly with the proper beta-aminopropionamidine, unsubstituted or substituted with one or two methyl groups in the amidine function. Most of the new analogues did not exhibit significant effects on the viruses studied, but three compounds (5f-h) displayed activity on herpes virus as demonstrated in plaque formation and virus yield assays. Elevated cytotoxicity was simultaneously observed for 5g and 5h. For compound 5f, a partial separation of antiherpes activity and cytotoxicity was accomplished. The differences in antiherpes activity did not correspond to the differences in the inhibition of herpes virus DNA polymerase.