Electrophysiological investigations of the brainstem in the vertebrobasilar reversible attacks

A total of 70 selected patients affected by reversible ischemic attacks in the vertebrobasilar system were studied. 50 patients presented transient ischemic attacks (TIA), while the other 20 patients suffered from 1-2 protracted transient ischemic attacks (PTIA). All patients underwent brainstem acoustic evoked potentials (BAEP) and electrooculography (EOG) 7-20 days from the last reversible ischemic attack, when all signs and symptoms completely disappeared. The combination of BAEP and EOG gave objective evidence of brainstem dysfunction in 61 out of 70 patients. BAEP resulted abnormal in 26 patients (16 TIA, 10 PTIA), EOG in 49 (36 TIA, 13 PTIA). Serial controls at 3, 6, and 12 months were conducted in 27 patients. 5 patients showed a normalization for BAEP and 7 for EOG 12 months after the first examination.

Combined partial temporal and secondary generalized status epilepticus. Report of a case with fear bouts followed by prolonged confusion

A right-handed 32-year-old woman had recurrent combined partial temporal and secondary generalized epileptic states almost constantly related to menstruations. During such more or less prolonged episodes sometimes the patient presented right adversive attacks with short postictal dysphasia. The catamenial status epilepticus observed in this cas was manifested in two clear-cut behavioral phases. The first phase was characterized by frequently recurrent left temporal epileptiform discharges without tendency to diffusion, progressively more prolonged and pseudorhythmic associated with a signalized feeling of intense fear without apparent impairment of consciousness or speech disturbances. The electroclinical features of the first phase suggest a depth origin of the paroxysms, probably due to a primary epileptogenic focus in the left amygdaloid-hippocampal complex. In the second phase the left temporal focal semirhythmic discharges associated with fear bouts became more frequent and prolonged and began to be followed by long-lasting generalized discharges resulting in a trance-like state with severe impairment of consciousness. The diffuse paroxysmal activity regularly preceded by the left temporal focal discharges was interpreted as a form of secondary bilateral synchrony constantly triggered from a focal pacemaker represented by the primary epileptogenic focus. During the very short transient periods of sudden cessation of the epileptiform activity the patient returned immediately to an apparent normal mental state. Good correlation could be established between different seizure patterns and predominant clinical signs. Intravenous diazepam rapidly decreased and then completely stopped the catamenial status epilepticus. Some problems related to the classification of these rare epileptic events are discussed.

Carcinogenic activity of benzo[a]pyrene and some of its synthetic derivatives by direct injection into the mouse fetus

We have studied the carcinogenic effects of direct injection of benzo[a]pyrene (BP) and 6-methylbenzo[a]pyrene (BP6M) into fetal Swiss mice at 15 days of intrauterine growth. To determine the sensitivity of mouse fetuses to the action of ultimate carcinogens, benzo[a]pyrene-4,5-oxide (BPO) and a racemic mixture of 7 beta,8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9, 10-tetrahydrobenzo[a]pyrene (BPDE), respectively, a proximal metabolite and an ultimate carcinogenic metabolite of BP, were also investigated in our system. The compounds were dissolved in acetone and trioctanoin (1:1) and injected at doses ranging from a minimum of 0.4 to a maximum of 19.8 nmol/fetus. Controls received 1 microliter/fetus of solvent. The experiment was terminated when the animals were 12-15 weeks old. On the basis of the percentages of lung adenomas and the average number of nodules/mouse, BPDE appears to be the most potent carcinogen of this group, causing 55% of tumors at a dose of 0.4 nmol and 73% at a dose of 4.0 nmol/fetus. At the dose of 0.4 nmol/fetus, neither BP nor BP6M induced tumors; injection of 4.0 or 19.8 nmol/fetus, caused incidences of 53% and 92%, respectively, in the case of BP6M and 24% and 39%, respectively, in the case of BP. BPO was not tumorigenic in this system, even at doses as high as 15.7 nmol/fetus. Eleven percent of the control animals had lung adenomas. The average number of nodules/mouse varied with the compound and the dose injected and closely followed the pattern of tumor incidence.

A comparative study of bovine, porcine and yeast superoxide dismutases

The Cu,Zn superoxide dismutases from bovine and porcine erythrocytes and from yeast have been investigated with the aim to identify structural differences in relation to possible functional variability in this highly homologous class of protein. The isoelectric points of the bovine, porcine and yeast proteins were found to be 4.8, 5.8 and 4.5 respectively. According to these values the net protein charge, as evaluated by gel electrophoresis, varied more significantly for the porcine protein than for the other two proteins tested. The catalytic constants were found to be higher at pH = 7.6 than at pH 10.0 for all the three enzymes. This relative increase was much more pronounced in the case of the porcine enzyme. The KM value at pH = 10.0 was also significantly higher for the porcine enzyme. Since the spectroscopic properties of the active sites were identical for the three proteins, these results point to modulation effects by positively charged amino acid residues on the superoxide dismutase activity of these proteins, in a way that the resultant net charge of the protein seems to be as important as specific residues.

Carbamoylation of Cu,Zn-superoxide dismutase by cyanate. Role of lysines in the enzyme action

Reaction with cyanate leads to a reversible change of the EPR spectrum of Cu,Zn-superoxide dismutase and to time-dependent carbamoylation of the lysine residues of the enzyme, producing a stable covalent derivative with more negative charge. The carbamoylated enzyme is less active than the native enzyme in spite of unaltered EPR spectra. The extent of this inactivation is much less when the enzyme activity is measured at low ionic strength. These results show that integrity of the active site is not the sole factor playing a role in the enzyme mechanism and that the ionic strength effect is related to electrostatic interactions between O-2 and surface charges of the protein.

Draft EEC method for the determination of the global migration of plastics constituents into fatty-food simulants: applicability to lacquers, plastics and laminates

An experimental study was carried out to establish whether the draft EEC method for the determination of the global migration of constituents from plastics packaging materials into fatty food simulants could be applied to all plastics, including lacquers and laminates. Some difficulties were encountered in the use of the EEC method for melamine, for hotmelt-coated packaging materials and for laminates containing one or more layers of materials sensitive to moisture, such as paper, cardboard or regenerated cellulose film.

[Continuous partial epilepsy in a case of cerebral abscess of long duration]

A patient affected by continuous clonus of the right half of his tongue and face with dysphasia and right hemiparesis is described. Partial continuous epilepsy of Kojewnikow was diagnosed. The CT scan showed a spreading lesion surrounded by intense oedema in the left central region, as well as a longstanding subdural hematoma complicated by osteitis. This finding lead to a diagnosis of cerebral abscess which was confirmed by surgery. In this paper it is also analyzed the cortical and/or subcortical origin of this peculiar type of epilepsia.

BAEP and autopsy findings in Wallenberg syndrome

BAEPs were recorded in a 70-year-old man who had developed symptoms indicative of Wallenberg syndrome. He died, of extracerebral causes, shortly after hospitalization and an autopsy study was done on the brainstem lesions. Right ear stimulation disclosed BAEP abnormalities, but gave no indication of the level of the ischemic disorder. Histopathological examination showed a typical right dorsolateral medullary infarct. A detailed study of the acoustic pathways demonstrated their anatomical integrity. These findings confirm the uncertainty that still exists as to the exact location and type of generators of BAEP components. They suggest, moreover, that BAEPs can give objective evidence of functional impairment of brainstem acoustic structures even in the absence of persistent anatomical damage.

Repeatability and reproducibility of determinations of vinyl chloride in foodstuffs

In the spring of 1978 and the autumn of 1979, two collaborative investigations were carried out with the aim of determining the variability of measurements of the vinyl chloride (VC) content of foodstuffs. The first investigation was a preliminary test on VC standards in N,N-dimethylacetamide. The results of this test were considered to be satisfactory. In a second test, lemonade and oil samples spiked with VC were investigated. The methods used were based on the headspace gas-chromatographic technique. The amount of VC added was 3 micrograms/kg for the lemonade sample and 20 micrograms/kg for the oil sample. The external standard method yielded a reproducibility of 53 and 39% and a repeatability of 18 and 17% for the lemonade and oil, respectively. The corresponding findings with the addition method were a reproducibility of 119 and 40% and repeatability of 33 and 9%.

[Lipid variations in coronary disease]

Levels of total cholesterol (TC), triglyceride (Tg), high-density-lipoprotein-cholesterol (HDL-C), apolipoproteins A and B (ApoA and ApoB), were assayed in the serum of 63 patients suffering from coronary atherosclerosis, who survived myocardial infarction (M.I.) compared to healthy subjects. TC was assayed by an enzymatic-colorimetric technique: after precipitation with PEG 6000 the same method was used to determine HDL-C. Tg were assessed using total enzymatic method and ApoA and ApoB by RID. On the basis of TC, Tg, HDL-C, ApoA and ApoB values we have identified 6 main patterns, presenting a very characteristic lipaemic model. No significant difference was found between survivors and controls as regards TC and Tg; on the contrary, there was a statistical difference between the two groups for HDL-C, ApoA and ApoB.

[The presence of 3,4-benzopyrene in plants I. Methods]

Purification methods of vegetable extracts have been experienced during our researches on the possible presence of the aromatic polycyclic hydrocarbons (particularly 3,4 benzopyrene) in vegetables. The validity of different methods has been determined by IR spectrophotometric analysis using special apparatus (IR-DATA-STATION). Vegetables extracts have been purified efficaciously by column chromatography, saponification and special methods (Grimmer's method). The described method eliminates, nearly entirely, the polluting substances that could alternate the chemical analysis of the vegetable extracts.

Pathologic changes in the cardiac conduction and nervous system in sudden coronary death

The arrhythmogenic substrates for sudden coronary death were studied in 13 autopsied hearts and in 2 left stellate ganglia (surgically excised). Diffuse or segmentary obstruction of nutritional arteries accounted for acute ischemic injury of the conduction system, which was the underlying cause of high-risk bradycardic arrhythmias in one-third of the cases. However, in one-quarter of the cases the survival of anoxia-resistant subendocardial specialized fibers was probably responsible for reentrant lethal tachycardic arrhythmias. In other cases, early infarct damage could have fatal arrhythmias of either type. Intrinsic and/or extrinsic neuropathologic changes, unbalancing the autonomic action on the heart, were often seen to participate in the arrhythmogenic features of sudden coronary death.

[Effects of 3,4-benzopyrene on the growth and development of the sunflower (Airelle variety) in experimental culture. II) Seed production]

Plants of sunflower cultivated in soil enriched in 3,4 benzopyrene produces seeds which are smaller than those obtained from untreated plants. The same effect has been observed if the leaves are sprinkled with BP. The smallest seeds are produced from plants submitted to soil and leaves treatment.

Fourth interlaboratory study of methods for determining total migration of plastic materials in liquids simulating fatty foodstuffs

Results are reported for the fourth interlaboratory study organized by the Commission of the European Communities for the adoption of an official method for determining the total migration of plastic materials in liquids simulating fatty foodstuffs. In each method, a sample of plastic material was weighed before and after it was placed in contact with fatty simulants. The fat absorbed by the sample, extracted or dissolved by suitable solvents, was determined by gas chromatography or radiometry. The results obtained confirm the conclusions given previously. Each method was moderately satisfactory, but less so between laboratories.