Enzymes are nature's catalysts, mediating chemical processes in living systems. The study of enzyme function and mechanism includes defining the maximum catalytic rate and affinity for substrate/s (among other factors), referred to as enzyme kinetics. Enzyme kinetics is a staple of biochemistry curricula and other disciplines, from molecular and…

The paper summarizes experimental evidence supporting a neurological theory which posits that autism, at least partially, represents a disruptive overactivation of hypersensitization of neurohormone systems in the brain, such as brain opioids. These substances modulate social-emotional processes. (Author/DB)

Although previous research with adult humans and nonhumans has suggested a relationship between sleep behavior and brain serotonin levels, no studies have been made of the relationship of normal children's or infants' sleep patterns to serotonin levels, tryptophan metabolism, or diet. This study investigates the relationship between dietary…

This commentary critiques two papers by Curt Sandman, pointing out interpretive problems in models explaining self-injurious behavior in terms of opioids. Withdrawal effects are emphasized as an alternative to hypotheses asserting congenital opioid excess as a cause of sensory depression or an addiction to a relative excess of opioid activity in…

This paper answers criticism (EC 601 030) of the authors' work regarding opioid explanations of self-injurious behavior. Possible withdrawal effects are ruled out as an explanation, in favor of opioid excess leading to sensory depression and addiction to relative excesses of opioid activity in the brain. Alternative models of consequences of…

Assessment of the neurotransmitter dopamine through measurement of the dopamine metabolite homovanillic acid (HVA) in adult subjects with mental retardation and with high rates of body stereotypy (n=12), compulsive behaviors (n=9), or neither (n=12) found lowest HVA concentrations in the stereotypy group and highest in the compulsive group. (DB)

This paper reviews what is known about the role of neurochemicals in controlling the development of the brain and in the pathophysiology of autism. Suggested approaches to further research involve using animal models, examining effects of drugs on neurochemicals, and using such technologies as positron emission tomography and magnetic resonance…

This study examined whether the variability in development in fragile X syndrome is related to FMR protein deficiency in 53 young males with various degrees of the syndrome. FMR protein expression accounted for a small but significant amount of variance in level, but not rate, of development. Findings support the hypothesized relationship but…

Plasma amino acid levels were measured in autistic (n=12), Asperger syndrome (n=11) patients, their parents and siblings. Patients with autism or Asperger syndrome and their siblings and parents all had raised glutamic acid, phenyalanine, asparagine, tyrosine, alanine, and lysine levels than age-matched controls. Results suggest dysregulated amino…

Reviews much of what is known about microtubules, which are biopolymers consisting predominantly of subunits of the globular protein, tubulin. Describes the functions of microtubules, their structure and assembly, microtube associated proteins, and microtubule-disrupting agents. (TW)

Discusses the biochemical mechanisms related to photosynthesis. Describes a water-oxidizing clock generating a molecule of oxygen with every four ticks. Lists four references. (YP)

This study of eight growth-retarded children with Down's syndrome (aged 1 to 6.5 years) found that administration of growth hormone was more effective than either L-dopa or clonidine. Results suggest that children with Down's syndrome have both anatomical and biochemical hypothalamic derangements resulting in decreased growth hormone secretion and…

Describes the nature and capabilities of methods used to characterize protein and peptide structure, indicating that they have undergone changes which have improved the speed, reliability, and applicability of the process. Also indicates that high-performance liquid chromatography and gel electrophoresis have made purifying proteins and peptides a…

This study investigated whether blood plasma levels of pro-opiomelanocortin-derived (POMC) peptides, beta-endorphin-like activity, adrenocorticotrophic hormone, and adrenal cortisol immediately after self injurious behavior (SIB) episodes predicted subsequent response to an opiate blocker in 10 patients with mental retardation. Results suggest…

Outlines the chemistry of the rapid synthesis of relatively large DNA fragments (100-200 monomers each) with yields exceeding 99 percent per coupling. DNA synthesis methodologies are outlined and a polymer-supported synthesis of DNA using deoxynucleoside phosphoramidites is described with structural formulas. (YP)