Analysis of variance study of the rat cortical layer 4 barrel and layer 5b neurones

Unique formation of rodent cortical barrels by layer 4 neurones attracts study of the sensory function of cortical input stage neurones (layer 4) compared with that of output stage neurones (layer 5). We have recorded extracellular responses from rat somatosensory cortical neurones to deflections of contralateral vibrissae. Thirty-two layer 4 barrel neurones and 29 layer 5b neurones were studied. Whisker stimulations were ramp-and-hold deflections with one of six different ramp velocities (100–2.5 mm s⁻¹) and one of four different plateau amplitudes (2000–200 μm). Twenty-four (6 × 4) different stimulus forms were applied to the tip of a whisker trimmed to 10 mm in a predetermined order in stimulus cycles of 20–50 repetitions. Spike counts for a period of 2560 ms in 10 ms bins were summed to construct a matrix of 24 peristimulus histograms for each neurone. Twenty-four amplitude and 24 velocity values were computed from counts during the plateau and ramp phases, respectively. To determine the amplitude- and velocity dependence of a neurone, an amplitude F value (the ratio of variations among-/within-amplitude of the amplitude value) and a velocity F value (ratio of variations among-/within-velocity of the velocity value) were derived by analysis of variance. The amplitude F value of the layer 4 barrel neurones was greater than that of the layer 5b neurones ( P < 0.0001). The velocity F value of the barrel neurones was smaller than that of the layer 5b neurones ( P = 0.0226). The results suggests that barrel neurones and layer 5b neurones tend to detect amplitude and velocity components of whisker deflection, respectively.     

Thyroid function in severely disabled children]

Thyroid function tests were studied in 105 severely disabled children. Fifty-four cases (53%) showed following abnormalities. Serum TSH concentration was increased in 2 cases. Both serum T4 and T3 levels were decreased in 18 cases (17%). Only the serum T4 level was decreased in 25 cases (24%). Only the serum T3 level was decreased in 10 cases (9.5%). Two patients showed primary hypothyroidism. Two patients (monozygotic twins) were suspected to have subclinical hypothalamic-pituitary hypothyroidism caused by septo-optic-dysplasia. Abnormal thyroid functions were caused by anticonvulsants in most patients. The serum T4 level was correlated with the number of anticonvulsants, but not correlated with motor performance (daily activity) or feeding function. Four patients who had low T4 level or low T4 and T3 levels were received L-thyroxine supplementation, but no clinical improvement was observed. The serum TSH concentration was decreased and the TRH test showed hyporeaction in all of these cases. The low T3 level and normal T4 level were not related to anticonvulsant administration. Two of these patients were in poor nutritional condition, resulting in so called low T3 syndrome.     

Cloning of regions required for contact hemolysis and entry into LLC-MK2 cells from Shigella sonnei form I plasmid: virF is a positive regulator gene for these phenotypes.

Two distinct regions required for both contact hemolysis and entry into LLC-MK2 cells were cloned into Escherichia coli from the Shigella sonnei form I plasmid, pSS120. The first region was cloned into an E. coli HB101 strain containing noninvasive Tn1 insertion mutants of the form I plasmid, and expression of ipa (invasion plasmid antigen) gene products was restored. The plasmid carrying the first region was then transformed into E. coli lacking the form I plasmid, and additional DNA fragments from the form I plasmid were cloned into the same recipient on compatible vectors. Five of these double transformants were found to be positive for contact hemolysis activity. Restriction analysis of these five clones indicated that the previously reported ipa locus and the invA locus were present on the second plasmid region. Only the strains carrying both of these regions were active in contact hemolysis and cell invasion assays. Several proteins, including the a, b, c, and d proteins encoded by the ipa genes, were detected in the double transformants by Western blot (immunoblot) analysis with serum of a monkey convalescing from shigellosis. A positive regulator was suggested to exist in the first region, since the amounts of most of these proteins were simultaneously increased in the presence of this region. Subcloning and nucleotide sequencing indicated that this positive regulator gene was virF. Product analysis of the virF gene with minicells showed that two peptides (30 and 21 kilodaltons) were synthesized and that at least the 30-kilodalton protein was essential for regulation of the ipa genes.     

Severe hypoglycaemia in a person with insulin autoimmune syndrome accompanied by insulin receptor anomaly type B.

AIMS: A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported. METHODS: Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone. RESULTS: Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies. CONCLUSIONS: The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy.