The Drosophila Mutant tetanic Interacts with a Gene Complex Including the Structural Locus of K+ Channels and Shows Altered Dephosphorylation and Learning

The tetanic (tta; X.-52.6) mutation has been isolated on the basis of its sensitivity to extradoses of the normal Shaker gene complex (ShC) where the K+ channel la is encoded. The mutant shows up to threefold elevation of the membrane bound protein phosphatase type 1 (PP1) activity in body extracts, probably due to reduced levels of the PP1 specific inhibitor 2 (I-2). By contrast, PP1 activity in the head is only half of the normal value. In addition, tta fails to perform normally in a negative reinforcement olfactory paradigm. The functional relationships between phosphorylation, K+ currents, phosphatase activity and modulation of synaptic activity during learning and memory are discussed in the light of their possible genetic links.     

Eating disorders in a population of students of a college environment: correlation with 2 psychosocial characteristics

The aims of this study were to measure the extent of severe eating disorders among female college students, to verify if there is a correlation with two indicators of "pressure to perform" while evaluating a screening instrument. Of 1144 female students, 16.3% scored 20 or above on the EAT-26 scale. Interviews allowed to determine that the positive predictive value of the EAT-26 when coupled with a low self-reported weight is considerably heightened. It was possible to estimate that over the last three years one girl out of 12 has presented severe eating disorders and one in 65 has suffered from anorexia nervosa. The EAT score was significantly correlated with the mother's level of schooling but not with the student's academic discipline.     

Therapeutic criteria in hydrocephalic children

The xanthine, hypoxanthine, and total oxypurine levels were determined in the CSF of 28 hydrocephalic patients (age from newborn to 2 years) and 8 healthy controls using HPLC. The Evans' index, the mean weekly increase in cranial circumference, and the intracranial pressure were also measured. Of the hydrocephalic patients 13 were self-compensated and the other 15 had a shunt implanted during the course of the study. The mean xanthine, hypoxanthine, and total oxypurine levels in the normal children were 5.20, 5.94, and 11.29 mol/l, respectively. In the self-compensated hydrocephalics these levels were 5.17, 5.71, and 10.79 mol/l, respectively. In the noncompensated hydrocephalics, they were 9.90, 9.91, and 19.82 mol/l. The differences between the latter group and the first two are statistically significant (P<0.001). The mean Evans' index and the mean weakly increase in cranial circumference in the self-compensated hydrocephalics were 0.35 and 0.25 cm, respectively. In the noncompensated hydrocephalics, they were 0.55 and 0.95 cm. The differences between the two groups are statistically significant (P<0.001). Two weeks after implantation of shunts in the noncompensated cases, the mean xanthine, hypoxanthine, and total oxypurine levels fell to 4.22, 4.57, and 8.80 mol/l, respectively. These changes are statistically significant (P<0.001). We think that the two criteria (clinical and biochemical) are equally useful for the prediction of self-compensation in hydrocephalic children and that the oxypurine values after shunt implantation can be used to monitor progress in noncompensated cases.     

Patterns and correlates of psychiatric hospitalization in a nationwide sample

Summary A nationwide random sample of psychiatric patients (n = 832) admitted for hospitalization in Israel in 1980 was followed up until the end of 1984 regarding their hospitalization patterns. Information about hospitalizations as well as demographic and diagnostic data were obtained from the Israel Central Psychiatric Case Register. Two main contrasting patterns of hospitalization emerged. One pattern consisted of a single short hospitalization during the entire follow-up period. This pattern was found among more than 50% of those patients for whom this hospitalization was the first in their life. The second pattern characterized the patients who accumulated long periods of inpatient stay, that is, at least one year during the follow-up period. These are the new chronic patients (about 30% of the total sample). About one third of these new chronic patients (8.2% of the total sample) accumulated their long stay through one continuous hospitalization, thus resembling the old chronic patients; two-thirds accumulated their long stay over several hospitalizations. Each patient has a fairly constant pattern of hospitalization, regarding the length of stay in hospital and out of hospital.     

Metabolism of methyl-branched iodo palmitic acids in cultured hepatocytes

The metabolic fate of methyl-branched iodo fatty acids was studied in primary culture of rat hepatocytes. We compared 16-iodo-2-R,S-methyl palmitic acid (2-Me), which can be oxidized, with 16-iodo-3-R,S-methyl palmitic acid (3-Me) which can be oxidized only after an initial oxydation and with 16-iodo-2,2-dimethyl palmitic acid (2,2-Me₂) and 16-iodo-3,3-dimethyl palmitic acid (3,3-Me₂) which cannot be oxidized at all. The normal fate of natural fatty acids was given by comparative experiments with [1-¹⁴C] palmitic acid. Monomethyl-branched iodo fatty acids were taken up in the same range as palmitic acid but more than dimethyl-branched iodo fatty acids. After a 15-h incubation, acido-soluble products (ASP) accounted for 75% of the radioactivity taken up as 16-iodo-2-methyl palmitic acid, 50% as other methyl-branched iodo fatty acids and only 30% as palmitic acid, which indicated that all the methyl-branched iodo fatty acids underwent a strong deiodination process. Fatty acids were esterified in the following order: palmitic acid >16-iodo-3-R,S-methyl palmitic acid>16-iodo-2-R,S-methyl palmitic acid>16-iodo-2,2-dimethyl palmitic acid>16-iodo-3,3-dimethyl palmitic acid. Cultured hepatocytes, labelled for 3 h with the various fatty acids and reincubated for 12 h without fatty acid, secreted large amounts of free dimethylbranched iodo fatty acids as compared to the monomethyl ones and palmitic acid. Only hepatocytes prelabelled with 16-[¹²⁵I]iodo-2,2-dimethyl palmitic acid exhibited an appreciable secretion of labeled triglycerides, but at a lower rate than with [1-¹⁴C] palmitic acid. Conversely, the 16-iodo-monomethyl palmitic acids remained chiefly in hepatocyte triglycerides. Minute amounts of 16-iodo-methyl-branched-palmitic acids were found in hepatocyte or secred phospholipids as compared with palmitic acid. This metabolic fate of methyl-branched iodo palmitic acids argues against their utilization as imaging probes to monitor in vivo the synthesis and the secretion of triglycerides by the liver.     

Structural and functional aspects of platelet-derived growth factor and its role in the pathogenesis of glioblastoma

The platelet-derived growth factor (PDGF) family consists of three different dimeric forms, AA, BB, and AB, of the two consitituent polypeptide chains, A and B. These interact with two different cell surface receptors that, in part, mediate different cellular functions. The various forms of PDGF, as well as the receptors, are expressed at high frequency in glioblastoma multiforme, and it has been suggested that the growth of this tumor might be affected by autocrine loops involving PDGF and its receptors. The present paper focuses on recent discoveries regarding the family of PDGF ligands and receptors, as well as reviews results concerning PDGF-dependent autocrine growth in experimental and spontaneous glioblastoma.     

Ventral spondylodesis: basic method in the treatment of cervical spine injuries

Ventral spondylodesis or ventrofixation is the most important surgical method for the treatment of severe cervical spine injuries accompanied by instability. Its wide indications include fracture-dislocations, compression fractures of the vertebral body, injuries to the disc, luxations, 'tear drop fractures' as well as "hangman's fractures". The essential parts of its technique: previous reduction by traction, anterior cervical approach, removal of the injured parts of vertebral body and disc(s), replacement by corticocancellous bone graft with subsequent plate-screw fixation. The authors performed in their Institute nearly 100 operations of this type, in a 10-year period of which; detailed account is given. Good results of surgery can be expected only by ensuring adequate technical conditions and professional knowledge, performing the operations in centres having sufficient experience.     

Legal aspects of visual field assessment

Visual field testing can fail to satisfy the standard of care if the optometrist does not test the patient's visual field when it is necessary, and if, even when testing is performed, it is of insufficient sensitivity. In general, the duty to test the visual field arises when examining symptomatic patients and when a suspicious finding is encountered, but "routine" eye health assessments should include a screening visual field test. In some cases the doctrine of informed consent will require the optometrist to inform the patient that testing of the visual field at threshold should be performed. Documentation of both test results and patient communications should be retained in the record.     

Fluid and electrolyte balance in the postoperative period

Authors investigated the concentration changes of arginine vasopressin (AVP) and of atrial natriuretic peptide (ANP) in plasma. The renal characteristics of water- and sodium metabolism in the first 24 hours of the postoperative period in 11 children operated with acute appendicitis have been studied. Crystalloid infusion was applied in 60 ml/kg/24 h dose, in 5 cases however, 1 g/kg albumin vas also administered during the operation. In children getting crystalloid infusion (group "A") the initial AVP value was 29.9 +/- 8.8 pg/ml, which further increased to 58.2 +/- 15.2 pg/ml (p 0.05) by the 6. postoperative hour and even in the 24. hour it remained above the physiological value (19.9 +/- 5.3 pg/ml). During the observation time significant Na- and water retention developed. The albumin administration (group "B") stopped the further increase of AVP values, the Na-household remained in equilibrium and the water retention developed only in smaller degree. The ANP plasma concentration of both groups was in the normal range and did not change during observation time. Our data show that for the postoperative water retention first of all the increased AVP activity is responsible. The more intensive AVP secretion may be induced by the relative intravascular hypovolemia since by enhancing the plasma volume the further increase of postoperative hormone activity could be prevented.     

Auditory evoked potentials to tones and syllables in adults: evidence of specific influence on N250 wave

Brain-derived neurotrophic factor (BDNF) is involved in the differentiation and the survival of neurons. It has also been shown to be associated with the regrowth of neurons of damaged spinal cord and the modulation of ionic currents by acting on sodium channels and NMDA receptors through tyrosine kinase B (TrkB) receptors. We investigated the effects of BDNF on rhythm generation induced by disinhibition in dissociated cultures from embryonic rat spinal cord (E14), with extracellular multisite recordings (MultiElectrode Arrays, MEAs) or intracellular patch-clamp recordings. Exogenous BDNF had only minor effects on the bursting by increasing the activity during the burst. This increase of activity is suggested to be mediated by a potentiation of the postsynaptic NMDA receptors because it has been found that BDNF potentiates the NMDA-evoked depolarization in cultures incubated with BDNF for 10 min. Possible direct effects of BDNF on sodium channels were also investigated by local application of BDNF to the soma of patched neurons but no depolarization was observed. Long-term application of BDNF strongly decreased the activity during the burst and also the number of active electrodes, possibly due to a decrease in network density.