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Objective: We present 3 cases of acute, occupational poisonings in workers exposed to lead during cutting and smelting discarded automobile storage batteries in a 'backyard' plant. Neuropsychological, neurological, examinations as well as EEG, CT scan and MRI were performed to assess the CNS lead neurotoxicity. Case Series: In the last days of October 2000, 3 patients were admitted to the Department of Clinical Toxicology with signs and symptoms of acute lead poisoning. Case 1: In a 36-year-old man, exposed to lead for 5 months, clinical examination revealed a severe encephalopathy (coma, brain edema, seizures), moderate anemia and slight liver dysfunction. Lead concentration in blood was 3100 [micro]g/L, excretion with urine 17.6 mg/24h, delta aminolevulinic acid (ALA) in urine-21.0 mg/L. CT scan performed in the first day confirmed diffuse cerebral edema. Chelating therapy with BAL and Ca[Na.sub.2]DTA was started immediately together with symptomatic and supportive treatment. MRI performed two weeks later revealed cortical and subcortical atrophy of the brain. In neuropsychological examination massive disorders of memory, thought processes, attention and learning ability were stated. In EEG epileptiform waves were observed. The last neurological examination showed proximal paresis in the upper extremities. Case 2: A 34-year-old man was exposed to lead for 5 weeks. At admission generalized weakness, dizziness, headache, abdominal pain and vomiting were observed. Laboratory findings revealed anemia and increased activity of the liver enzymes. Lead blood concentration was 1200 [micro]g/L, lead urinary excretion-16.8 mg/24h, ALA in urine-52 mg/L. Neuropsychological examination showed disorders in non-verbal functions. The CT scan and MRI of the brain showed slight cortical and subcortical atrophy. EEG was normal. Neurological examination revealed tremor of upper extremities and nystagmus. Chelating therapy with BAL and Ca[Na.sub.2]DTA was started. Case 3: A 21-year-old man was exposed to lead for 1 week. He presented only abdominal pain and weakness. Blood lead concentration was 1200 [micro]g/L, lead urinary excretion-3.8 mg/24h, ALA in urine-55.1 mg/L. Laboratory results: insignificant anemia and increased activity of the liver enzymes were observed. Moderate impairment of memory was stated in neuropsychological tests. CT scan, MRI and EEG did not reveal significant changes. Neurological examination: nystagmus and dysesthesia were observed. The treatment was started with DMPS and then continuing with Ca[Na.sub.2]DTA. Peripheral nervous system evaluation will be performed and further dynamic investigations are planed. Conclusion: In all patients exposed to lead by inhalation at the workplace, the blood lead concentration was in the range that causes severe neurotoxicity. The severity of the CNS manifestations was related to the blood lead concentration and the time of exposure. Groszek B, Pach J, Hydzik P, Szczepanska L. Department of Clinical Toxicology College of Medicine, Jagiellonian University, Krakow, Poland

The results concerning the elastic properties of glycinium phosphite (GPI) crystals obtained by Brillouin scattering method are reported. The temperature measurements of the relative change AVN of the phase velocity for acoustic modes propagating in q = [100], q = [010], q = [110] and q = [011] directions have been performed in the temperature range 300 K - 170 K. Obtained results confirm the existence of the ferroelectric phase transition (P21/a - P21) at 224 K.

EPR of γ-ray generated PO32- radicals indicates that the four radical centers are equivalent in the paraelectric phase and become inequivalent in the ferroelectric phase due to a ±3° rotation. The phase transition temperature is shifted by irradiation from Tc = 224 K to Tc = 180 K. The molecular mechanism of the order-disorder phase transition is discussed

Following our previous communication1 about the glass state in Rb0.69(NH4)0.31H2AsO4 system a dielectric study at X-band of the mixed crystals of Rb1-x(NH4)xH2AsO4 was made in a wide concentration range x. Both ε'. and ε'' were studied between 5 and 300 K. From dielectric measurements the phase diagram was determined. In the RADA system a proton glass state exists in the concentration range 0.1 < x < 0.5.

Ferroelectric domain structure of tetramethylammonium zinc chloride was revealed in the temperature range 275. 8R-279. OK by means of scanning electron microscopy. The domain patterns of lamellar type were observed. The mean width of the domains at 276.1 K amounted to 10 μm.

Temperature variation of the pyroelectric response Up was studied for NaNH4SO4.2H2O single crystals. In spite of the bulk pyroelectric response veryfied by flux modulation frequency dependence of Up in the ferroelectric phase, a small, frequency independent pyroelectric response was observed in the paraelectric phase up to ∼ 200 K. Moreover, the pyroelectric response is accompanied by Barkhausen pulses. The high temperature tail of Up(T) is attributed by us to the water defects in the crystals.

The aim of the paper was a search for polymorphism in LiNH4SeO4 (LASe) single crystals and the study of the structure of the only known α-modification of LASe. We found the α-LASe to be isomorphous with α-LiNH4SO4 (the space group Pca21). Two kinds of polytypes, the A with cA = c and the B with cB = 2c, were observed. The two polytypes were found to exist simultaneously in each single crystalline sample with the B-polytype prevailing. This superstructure is found to affect the α rightarrow β polymorphous transformation.