Glutamatergic deficits and parvalbumin-containing inhibitory neurons in the prefrontal cortex in schizophrenia.

BACKGROUND: We have previously reported that the expression of the messenger ribonucleic acid (mRNA) for the NR2A subunit of the N-methyl-D-aspartate (NMDA) class of glutamate receptor was decreased in a subset of inhibitory interneurons in the cerebral cortex in schizophrenia. In this study, we sought to determine whether a deficit in the expression of NR2A mRNA was present in the subset of interneurons that contain the calcium buffer parvalbumin (PV) and whether this deficit was associated with a reduction in glutamatergic inputs in the prefrontal cortex (PFC) in schizophrenia. METHODS: We examined the expression of NR2A mRNA, labeled with a 35S-tagged riboprobe, in neurons that expressed PV mRNA, visualized with a digoxigenin-labeled riboprobe via an immunoperoxidase reaction, in twenty schizophrenia and twenty matched normal control subjects. We also immunohistochemically labeled the glutamatergic axon terminals with an antibody against vGluT1. RESULTS: The density of the PV neurons that expressed NR2A mRNA was significantly decreased by 48-50% in layers 3 and 4 in the subjects with schizophrenia, but the cellular expression of NR2A mRNA in the PV neurons that exhibited a detectable level of this transcript was unchanged. In addition, the density of vGluT1-immunoreactive boutons was significantly decreased by 79% in layer 3, but was unchanged in layer 5 of the PFC in schizophrenia. CONCLUSION: These findings suggest that glutamatergic neurotransmission via NR2A-containing NMDA receptors on PV neurons in the PFC may be deficient in schizophrenia. This may disinhibit the postsynaptic excitatory circuits, contributing to neuronal injury, aberrant information flow and PFC functional deficits in schizophrenia.

Growth of intelligence: failure and catch-up associated respectively with abuse and rescue in the syndrome of abuse dwarfism.

IQ change in association with change of environment occurred in a sample of 34 patients with a diagnosis of abuse dwarfism. Low and persistent impairment of IQ was associated with abuse. By contrast, IQ elevation was associated with rescue. Multiple regression analysis revealed that duration of rescue was the primary variable associated with IQ elevation; age and IQ level at rescue were secondary. IQ elevation was gradual and progressive over the years, as rescue was maintained. In abuse, the mean IQ was 66 (range, 36-101), and after rescue it was 90 (range 48-133). The greatest magnitude of change, from IQ 36 to 120, was in a girl between the ages of 3 yr 8 months and 13 yr 11 months.

Skin test for gluten-sensitive enteropathy using subfractions of gluten.

Fractions and subfractions of gluten were used for intradermal testing in 14 patients with GSE and in 22 control subjects. Twelve out of 14 GSE patients gave positive skin reactions to one or more of the subfractions of gluten. Ten gave a positive reaction between three to eight hours after skin testing; two gave positive tests 20 minutes after injection. Only two out of the 14 had negative skin tests at all times tested. All 22 control subjects were negative to all the subfractions at all times tested. The control subjects consisted of 15 patients with GI disorders other than GSE, three patients with skin disorders other than dermatitis herpetiformis and four healthy controls. Of the three subfractions tested, subfraction B1 appeared most potent in evoking positive skin reactions as judged by the number of GSE patients who responded (11 of 14). Thus, skin testing individuals with this particular portion of gluten subfraction BA may prove to be a useful diagnostic test for GSE.

Sodium and other inorganic growth requirements of bacteroides amylophilus.

Bacteroides amylophilus has growth requirements for Na(+), PO(4) (3-), K(+), and small quantities of Mg(2+). No requirement could be shown for Ca(2+) in media previously found growth-yield-limiting for Bacteroides succinogenes. Deletion of Co(2+), Mn(2+), Cl(-), or SO(4) (2-) did not affect growth. Quantitative studies indicate that Na(+), K(+), and PO(4) (3-) have differing effects on the growth of B. amylophilus. A concentration of sodium and potassium ions affects both growth rate and growth yield, whereas a phosphate concentration markedly affects growth yield, but affects growth rate only slightly, if at all. The sodium requirement of B. amylophilus is absolute. It cannot be replaced by K(+), Li(+), Rb(+), or Cs(+). The latter three monovalent cations are toxic to B. amylophilus if supplied to the organism at Na(+)-replacing concentrations. K(+) is inactive at similar concentrations. The K(+) requirement of B. amylophilus may be satisfied by Rb(+). The concentration of Na(+) required by B. amylophilus for abundant growth suggests that B. amylophilus should be considered a slightly halophilic organism. The results suggest that Na(+) may be a more frequent requirement among terrestial bacteria obtained from relatively low-salt environments than has been previously believed.