Sequential loss of two neighboring exons of the tropoelastin gene during primate evolution.

Previous evidence has demonstrated the absence of exons 34 and 35 within the 3' end of the human tropoelastin (ELN) gene. These exons encode conserved polypeptide domains within tropoelastin and are found in the ELN gene in vertebrate species ranging from chickens to rats to cows. We have analyzed the ELN gene in a variety of primate species to determine whether the absence of exons 34 and 35 in humans either is due to allelic variation within the human population or is a general characteristic of the Primates order.

Quantitation of tropoelastin mRNA and assessment of alternative splicing in human skin fibroblasts by reverse transcriptase-polymerase chain reaction.

We have developed a reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the quantitative measurement of levels of tropoelastin mRNA in total RNA preparations from skin fibroblasts. This method facilitates the reproducible detection of low abundance tropoelastin mRNA in the range of 10-1000 copies per cell. The procedure is based on a competitive RT-PCR assay where a tropoelastin cDNA-derived internal RNA standard is cotranscribed and coamplified together with the sample derived-endogenous target mRNA.

The substitution of arginine for glycine 85 of the alpha 1(I) procollagen chain results in mild osteogenesis imperfecta. The mutation provides direct evidence for three discrete domains of cooperative melting of intact type I collagen.

We report a case of mild osteogenesis imperfecta in a 56-year-old male undergoing aortic valve replacement surgery. The primary defect in this patient was the substitution of arginine for glycine 85 in one of the two chains of alpha 1(I) procollagen. The thermal stability of the type I collagen synthesized by the patient's cultured skin fibroblasts was examined by enzymatic digestion.

Psychophysics of muscle tension in psychiatric inpatients.

Twelve psychiatric inpatients and 16 control subjects each took part in a psychophysics experiment in which the method of production was used to study the perception of tension in the frontalis and forearm extensor muscles. Subjects tensed each muscle between 0% and 50% maximum effort, with 25% effort repeated every third trial, and used as a reference stimulus. Patients showed significantly lower correlations between frontalis EMG and percent effort than the control subjects, but no between-groups differences were found for forearm.

Bromocriptine for "negative" schizophrenia.

The hypothesis that the pathophysiology of negative symptoms in schizophrenia may involve relative hypoactivity of central dopaminergic neurotransmission prompts the exploration of dopamine agonist strategies in the treatment of this condition. Although the use of dopamine agonists in otherwise unmedicated schizophrenic patients often leads to the exacerbation of psychosis, trials of dopamine agonists in combination with neuroleptic agents warrant investigation. We therefore report on open clinical experience involving six patients with chronic negative symptoms of schizophrenia, maintained on neuroleptic medication, who appeared to have favorable responses to the addition of moderate doses of bromocriptine (10 to 20 mg/d orally in divided doses).