Urinary excretion of 5-oxoproline (pyroglutamic aciduria) as an index of glycine insufficiency in normal man

1. The evidence is accumulating to suggest that glycine, the simplest amino acid, is conditionally essential in man. Benzoic acid, by conjugation with glycine to form hippuric acid, is known to deplete the free glycine pool of the body. Glycine is one substrate for the enzyme glutathione synthase (EC 6.3.2.3) and in the inborn error of metabolism in which glutathione synthase function is defective, increased quantities of 5-oxoproline are excreted in the urine. 2. An oral dose of 4-10 g sodium benzoate was given to six normal adults to deplete the metabolic pool of glycine, and the urinary excretion of 5-oxoproline was followed for 6 h. In five of the six, a significant increase in the urinary 5-oxoproline was seen within 3 h. 3. These findings show that 5-oxoprolinuria can result from limited glycine availability, and may provide a useful test for assessing glycine sufficiency in a range of physiological and pathological states.     

Magnetic resonance imaging of foot and ankle trauma

MRI is a useful diagnostic tool in the assessment of traumatic lesions of the foot and ankle. It is especially useful in demonstrating acute and chronic tendon and ligament injuries. Subtle fractures, including osteochondral, nondisplaced, and stress fractures, are well shown with MRI but may be difficult to detect on radiographs. A bone scan may also be used to detect these fractures; however, with MRI the fracture extent may be determined. MRI is also useful in diagnosing complication of trauma, such as ischemic necrosis and bone and soft-tissue infections.     

Preliminary evidence for a role of apolipoprotein E alleles in identifying haemodialysis patients at high vascular risk

Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.      

A human immunodeficiency virus-resistant airway for cardiopulmonary resuscitation.

Due to fear of transmitted disease, mouth-to-mouth cardiopulmonary resuscitation (CPR) is now rare, even though early CPR is associated with a fivefold to 30-fold increase in survival. The authors have devised a one-piece silicone mask (Kiss of Life [KOL], Brunswick Biomedical Technologies, Inc, Warehom, MA) with a one-way valve and circular recess to form a no-contact lip seal, enabling mouth-to-mouth CPR to be given. The ventilatory volume during mannequin CPR using the KOL mask was 0.75 +/- 0.235 L. This volume was significantly (P less than .05) greater than that generated by alternate widely used airways (range, 0.195 +/- 0.147 to 0.617 +/- 0.208 L). To assess mask performance in vivo, the authors measured exhaled volumes in 10 apneic anesthetized patients under three conditions: with the KOL mask, a standard anesthetic mask and bag, and an anesthetic mask with an endotracheal tube. The results were: anesthetic mask and tube, 1.5 L (range, 1.2 to 1.7 L); KOL mask, 1.1 L (range, 1.0 to 1.3 L); anesthetic mask alone, 0.7 L (range, 0.5 to 0.8 L). To test permeability, we exposed two KOL masks to a high titer of human immunodeficiency virus (HIV)-1 soup (10(6) culture infection doses/mL) for 10 and eight masks for 60 minutes, respectively, and cultured swabs of the interior of the valve for 1 month. There was no growth in any culture. These data suggest that the KOL mask has excellent ventilating characteristics, is practical (pocket-portable, disposable), experimentally impermeable to HIV-1, and inexpensive.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ectoparasites of a population of urban gray squirrels in northern Florida

Ectoparasites infesting a population of urban gray squirrels (Sciurus carolinensis Gmelin) in northern Florida were collected monthly during 1974. Eleven species were identified: one flea (Orchopeas howardi (Baker], three suckling lice (Enderleinellus longiceps Kellogg & Ferris, Hoplopleura sciuricola Ferris, and Neohaematopinus sciuri Jancke), one tick (Dermacentor variabilis Say), two mesostigmatid (gamasid) mites (Androlaelaps casalis (Berlese) and A. fahrenholzi (Berlese], and four chiggers (Eutrombicula alfreddugesi (Oudemans), E. splendens (Ewing), Leptotrombidium peromysci Vercammen-Grandjean & Langston, and Parasecia gurneyi (Ewing]. The flea and three suckling lice represent core species of ectoparasites for the gray squirrel; the remainder are probably satellite species. Only E. longiceps varied significantly in prevalence or intensity of infestation among host age groups; subadult squirrels had higher intensities than adults. Peak prevalence of O. howardi occurred in January and attained maximum intensity in March, whereas both prevalance and intensity were minimum in August. Prevalence of H. sciuricola was maximum in November and remained at similar levels through June. It then declined significantly to its minimum in September-October. Intensity of infestation, however, was greatest in August, September, and January. Maximum prevalence of N. sciuri occurred from January to March and was minimum in September; intensity of infestation reached maxima in January, June, and August.     

Amygdalar kindling is associated with elevated zinc concentration in the cortex and hippocampus of rats

The reported convulsant properties of zinc and its association with hippocampal function prompted investigation of zinc levels during the induction and maintenance of kindling. Rats were fed zinc adequate diets during kindling, incited by daily amygdalar stimulation. The concentration of zinc in hippocampus was unperturbed during 3 stages of kindling induction when compared to either naive, sham surgery, or electroshock controls. In contrast, cortical zinc increased during kindling induction but returned to control levels in fully kindled animals. Two weeks after full kindling was established, the concentration of zinc in the hippocampus and overlying cortex increased significantly, in the absence of further electrical stimulation. The effect was restricted to the central nervous system inasmuch as zinc levels were unaffected in liver and other extracerebral tissues. Moreover, the zinc concentration was relatively unchanged during the 24 h period following a single electroconvulsive seizure, implying that the observed changes were not simply a postictal phenomenon. The results of this study suggest that long-lasting elevations in zinc are present after kindling is established. Whether this finding is related to the perpetuation of abnormal neuronal excitability or represents a compensatory response remains to be elucidated.