Age and simple reaction time: decade differences for 5,325 subjects

In a booth at a public exhibition entitled "Medicines for Man," 5,325 men, women, and children carried out a 1-minute test of simple reaction time (RT) with 1 to 10 second randomized variable preparatory interval (PI). They recorded their ages by decade. Average RT over the last eight (of ten) trials increased progressively from the 20s up to age 60 and over, and downward to the teens and under 10s. The single fastest RT in each test varied much less with age, only the 20s being clearly faster than the rest, with the under 10s slower. Within-subject variability of RT was increased only in the under 10s and over 60s. Ability to sustain attention during the longer PIs may underlie the gross average RT differences with age, and possibly some more basic neural property the superiority of the 20s in fastest RT.     

Production of delayed hypersensitivity by antigen associated with peritoneal exudate cells and the effect of pretreatment with Freund's complete adjuvant

The immunogenicity of antigens associated with peritoneal exudate cells was compared with the immunogenicity of free antigens for the induction of delayed hypersensitivity. Oil induced peritoneal exudate cells were incubated with antigens labelled with radioactive iodine, washed and injected intraperitoneally into recipient guinea-pigs. Comparable amounts of free antigens were also injected. All sixteen inbred guinea-pigs given human or bovine gamma-globulin associated with peritoneal exudate cells gave positive reactions (greater than 5 mm) while the eighteen guinea-pigs given free antigens failed to show a reaction. Similar results were obtained with serum albumins in inbred guinea-pigs. The increased immunogenicity of antigens associated with peritoneal exudate cells was also seen in outbred guinea-pigs.

Pretreatment with Freund's complete adjuvant did not depress the immunogenicity of antigens associated with peritoneal exudate cells and actually increased the induration of the 24-hour reaction to picrylated human serum albumin and human serum albumin associated with peritoneal exudate cells.

     

Reduced high-energy phosphate levels in rat hearts. I. Effects of alloxan diabetes.

Significant alterations in heart carbohydrate and lipid metabolism are present 48 h after intravenous injection of alloxan (60 mg/kg) in rats. It has been suggested that uncoupling of oxidative phosphorylation occurs in the alloxanized rat heart in vivo, whereas normal oxidative metabolism has been demonstrated in alloxan-diabetic rat hearts perfused in vitro under conditions of adequate oxygen delivery. We examined the hypothesis that high-energy phosphate metabolism might be adversely affected in the alloxan-diabetic rat heart in vivo. Phosphocreatine and ATP were reduced by 58 and 45%, respectively (P is less than 0.001). Also, oxygen-dissociation curves were shifted to the left by 4 mmHg, and the rate of oxygen release from blood was reduced by 21% (P is less than 0.01). Insulin administration normalized heart high-energy phosphate compounds. ATP production was accelerated in diabetic hearts perfused in vitro with a well-oxygenated buffer. These studies support the hypothesis that oxidative ATP production in the alloxan-diabetic rat heart is reduced and suggest that decreased oxygen delivery may have a regulatory role in the oxidative metabolism of the diabetic rat heart.     

Genotypic and phenotypic variability of 22q11.2 microduplications: An institutional experience

Duplications in the 22q11.2 region can cause 22q11.2 duplication syndrome and encompass a variety of phenotypes including developmental delays, facial abnormalities, cardiovascular defects, central nervous system delays, and other congenital abnormalities. However, the contribution of these contiguous duplicated regions to the clinical phenotypes has not been fully elucidated. In this study, we identified nine patients carrying different 22q11.2 microduplications detected by chromosomal microarray. Of these patients, seven pediatric patients presented with various clinical features including two neonate cases died shortly after birth, and two healthy adults. We examined region specific genotype–phenotype associations and found unpredictability associated with 22q11.2 duplications in these nine patients.     

Radioprotective potential of ginseng

A majority of potential radioprotective synthetic compounds have demonstrated limited clinical application owing to their inherent toxicity, and thus, the seeking of naturally occurring herbal products, such as ginseng, for their radioprotective capability has become an attractive alternative. In general, ginseng refers to the roots of the species of the genus Panax. As a medicinal herb, ginseng has been widely used in traditional Chinese medicine for its wide spectrum of medicinal effects, such as tonic, immunomodulatory, antimutagenic, adaptogenic and antiaging activities. Many of its medicinal effects are attributed to the triterpene glycosides known as ginsenosides (saponins). This review addresses the issue of the radioprotective effects of ginseng on mammalian cells both in vitro and in vivo. Results indicate that the water-soluble extract of whole ginseng appears to give a better protection against radiation-induced DNA damage than does the isolated ginsenoside fractions. Since free radicals play an important role in radiation-induced damage, the underlying radioprotective mechanism of ginseng could be linked, either directly or indirectly, to its antioxidative capability by the scavenging free radicals responsible for DNA damage. In addition, ginseng's radioprotective potential may also be related to its immunomodulating capabilities. Ginseng is a natural product with worldwide distribution, and in addition to its antitumor properties, ginseng appears to be a promising radioprotector for therapeutic or preventive protocols capable of attenuating the deleterious effects of radiation on human normal tissue, especially for cancer patients undergoing radiotherapy.     

Epidemiologic and diagnostic evaluation of a recent mumps outbreak using oral fluid samples.

OBJECTIVE: To determine the optimal strategy to investigate mumps virus infection in a partially vaccinated cohort. STUDY DESIGN: 122 oral fluid and serum samples were collected in a recent outbreak in Ireland. The largest age cohort, students aged 18-21 years old attending third level institutions, were investigated using virus isolation, detection of mumps specific IgM, IgG, RT-PCR and molecular genotyping. RESULTS: 97% of patients had both detectable serum IgM and IgG. Mumps virus RNA was detected in 17 oral fluid samples and 14 of these originated from a single geographic location. Only 6 of the IgM positive samples had detectable mumps virus RNA whereas this could be detected in 11 IgM negative samples. Genotyping studies revealed that genotypes G and J were co-circulating during this outbreak. CONCLUSIONS: The use of an oral fluid sample to detect mumps virus RNA and IgM offers a major improvement over serological diagnosis in acute infection in both non-vaccinated or partially vaccinated individuals, and has the advantage that specimens are collected non-invasively.