Biochemical and molecular analysis of the mammalian cytoplasmic dynein intermediate chain.

Cytoplasmic dynein is a multisubunit protein complex responsible for the intracellular movement of membranous organelles and other cargo along microtubules. The heavy chains contain the motor domains, while the intermediate chain and other subunits are important for binding to cargo. There are at least five different intermediate chain polypeptides, the products of alternative splicing of two genes. The cytoplasmic dynein intermediate chains are also phosphorylated. The expression of the different intermediate chain mRNAs is characterized by reverse transcription-polymerase chain reactions using oligonucleotide primers appropriate for the alternative splicing sites. The presence of the different intermediate chain polypeptide isoforms is determined by two-dimensional gel analysis of cytoplasmic dynein samples. The phosphorylation state of the polypeptides is determined by treatment of immunoprecipitated cytoplasmic dynein with protein phosphatase and analysis of changes in polypeptide spot distribution after two-dimensional gel electrophoresis.

Planum temporale asymmetry reversal in schizophrenia: replication and relationship to gray matter abnormalities.

OBJECTIVE: The planum temporale, the posterior superior surface of the superior temporal gyrus, is a highly lateralized brain structure involved with language. In schizophrenic patients the authors previously found consistent reversal of the normal left-larger-than-right asymmetry of planum temporale surface area. The original subjects plus new patients and comparison subjects participated in this effort to replicate and extend the prior study. METHOD: High-resolution magnetic resonance imaging of 28 schizophrenic patients and 32 group-matched normal subjects was performed. The authors measured planum temporale surface area, gray matter volume underlying the planum temporale, and gray matter thickness. Asymmetry indices for areas and volumes were calculated. RESULTS: Overall gray matter and total brain volume were not significantly smaller in the patients than in the comparison subjects. As previously reported, there was striking reversal of the normal asymmetry for planum temporale surface area in the male and female schizophrenic subjects. Bilaterally, gray matter volume beneath the planum temporale was smaller in the schizophrenic patients, and the gray matter thickness of the right planum temporale was only 50% of the comparison value. Volume of planum temporale gray matter did not show significant asymmetry in either group. CONCLUSIONS: This study extends the finding of reversed planum temporale surface area asymmetry in schizophrenic patients and clarifies its relationship to underlying gray matter volume. Although right planum temporale surface area is larger than normal in schizophrenia, gray matter volume is less than the comparison value; thus, gray matter thickness is substantially less than normal.

Asymmetry of the planum temporale: methodological considerations and clinical associations.

Asymmetry of the planum temporale, a region on the posterosuperior surface of the temporal lobe involved in the production and comprehension of language, is a notable feature of the normal human brain. Several attempts have been made to measure it using both post-mortem and magnetic resonance imaging (MRI) methods, but previous approaches made inadequate allowance for the convoluted nature of the structure. The current study used rigorous criteria to define the planum and examined three separate approaches for its measurement on MRI scans. A method involving triangulation of the surface consistently gave larger values for the surface area of the planum, suggesting that this method takes account of the convoluted nature of the structure.