Comparison of the quasifree charge-exchange reaction for 12C and 54Fe

Serotonin (5-hydroxytryptamine, 5-HT) in blood is stored in platelets and has vascular and platelet stimulating effects when released into plasma. Accurate measurements of 5-HT in plasma are complicated by inadvertent platelet activation causing sampling artifacts and by analytical problems when determining trace levels. We developed an assay for plasma 5-HT based on solid-phase extraction (Sep-Pak C18), aqueous acetylation, pentafluoropropionylation, and negative ion chemical ionization gas chromatography-mass spectrometry. The method was able to recover 5-HT from plasma by > 90% and to quantitate with a precision of 7.5% at a level of 0.5 nmol/l. It was used to define blood sampling and sample handling procedures giving low and consistent values for 5-HT. A good blood sampling technique, adequate platelet stabilization in the test tube, and rapid high speed centrifugation of the blood resulted in low plasma levels of both 5-HT and beta-thromboglobulin (a platelet release product). Using these procedures plasma 5-HT levels in healthy volunteers were found to be 0.77 +/- 0.38 (mean +/- S.D.; range 0.27-1.49) nmol/l (n = 18), which is 4-100-fold lower than previously reported values.     

The impact of HIV on infectiousness of pulmonary tuberculosis: a community study in Zambia

Isolated ventral and dorsal rat spinal roots incubated in normal (2.5 mM) or high glucose (25 mM) concentrations or in high concentrations of other hexoses were exposed transiently to hypoxia (30 min) in a solution of low buffering power. Compound nerve action potentials, extracellular direct current potentials, and interstitial pH were continuously recorded before, during, and after hypoxia. Ventral roots incubated in 25 mM D-glucose showed resistance to hypoxia. Dorsal roots, on the other hand, revealed electrophysiological damage by hyperglycemic hypoxia as indicated by a lack of posthypoxic recovery. In both types of spinal roots, interstitial acidification was most pronounced during hyperglycemic hypoxia. The changes in the sensitivity to hypoxia induced by high concentrations of D-glucose were imitated by high concentrations of D-mannose. In contrast, D-galactose, L-glucose, D-fructose, and L-fucose did not have such effects. Resistance to hypoxia, hypoxia-generated interstitial acidification, and hypoxia-induced electrophysiological damage were absent after pharmacological inhibition of nerve glycolysis with iodoacetate. These observations indicate 1) that enhanced anaerobic glycolysis produces resistance to hypoxia in hyperglycemic peripheral nerves and 2) that acidification may impair the function of peripheral axons when anaerobic glycolysis proceeds in a tissue with reduced buffering power.     

Somatic cell cloned transgenic bovine neurons for transplantation in parkinsonian rats

OBJECTIVE: To identify consistent relevant mechanisms of small intestinal dysfunction in cats with experimentally induced feline immunodeficiency virus infection (FIV) that developed chronic diarrhea during the time they were being used in studies of pathogenicity and transmission of FIV. ANIMALS: 10 cats. PROCEDURE: The following investigative tests and techniques were performed on each of the cats: routine hematologic and serum biochemical analyses; urinalysis; fecal parasitologic and microbiologic examinations; breath hydrogen lactulose (BH2LT) and xylose (BH2XT) tests; intestinal permeability test; endoscopic examination of the intestinal mucosa; bacteriologic culture of endoscopically collected small intestinal juice; and histologic examination of endoscopically obtained intestinal biopsy specimens. RESULTS: Neutrophilia was evident in 3 cats, and lymphopenia was detected in 2 cats. Serum biochemical abnormalities were not observed. Urinalysis results were unremarkable. Fecal bacteriologic and parasitologic results were normal, except for isolation of Campylobacter sp from 1 cat. Abnormal BH2XT values suggestive of D-xylose malabsorption were identified in 2 cats, and BH2LT values indicated evidence of small intestinal bacterial overgrowth in 1 cat. Finally, permeability test results, quantitation of bacterial flora from the proximal part of the small intestine and histologic examination of biopsy specimens did not reveal any abnormalities. CONCLUSIONS: Enteric pathogens did not account for the development of diarrhea in cats with experimentally induced FIV infection, and consistent relevant mechanisms of small intestinal dysfunction were not identified.     

Mitochondrial DNA Fragmentation as a Molecular Tool to Monitor Thermal Processing of Plant‐Derived,Low‐Acid Foods,and Biomaterials

Cycle threshold (Ct) increase, quantifying plant‐derived DNA fragmentation, was evaluated for its utility as a time‐temperature integrator. This novel approach to monitoring thermal processing of fresh, plant‐based foods represents a paradigm shift. Instead of using quantitative polymerase chain reaction (qPCR) to detect pathogens, identify adulterants, or authenticate ingredients, this rapid technique was used to quantify the fragmentation of an intrinsic plant mitochondrial DNA (mtDNA) gene over time‐temperature treatments. Universal primers were developed which amplified a mitochondrial gene common to plants (atp1). These consensus primers produced a robust qPCR signal in 10 vegetables, 6 fruits, 3 types of nuts, and a biofuel precursor. Using sweet potato (Ipomoea batatas) puree as a model low‐acid product and simple linear regression, Ct value was highly correlated to time‐temperature treatment (R² = 0.87); the logarithmic reduction (log CFU/mL) of the spore‐forming Clostridium botulinum surrogate, Geobacillus stearothermophilus (R² = 0.87); and cumulative F‐value (min) in a canned retort process (R² = 0.88), all comparisons conducted at 121 °C. D₁₂₁ and z‐values were determined for G. stearothermophilus ATCC 7953 and were 2.71 min and 11.0 °C, respectively. D₁₂₁ and z‐values for a 174‐bp universal plant amplicon were 11.3 min and 9.17 °C, respectively, for mtDNA from sweet potato puree. We present these data as proof‐of‐concept for a molecular tool that can be used as a rapid, presumptive method for monitoring thermal processing in low‐acid plant products.     

Cerebrospinal fluid findings in asymptomatic patients with reactive serum fluorescent treponemal antibody absorption tests

It is common to examine the cerebrospinal fluid in untreated or inadequately treated asymptomatic patients with a reactive serum fluorescent treponemal antibody absorption (FTA-ABS) test before initiating antibiotic therapy for syphilis. This prospective study evaluated the usefulness of such examination. Four hundred thirty-two patients over 40 years old, reporting for annual physical examination, had a serum FTA-ABS test. Thirty-seven (8.6%) patients and 2 of 4 spouses were reactive repeatedly. Of the 39 patients with reactive tests, 7 had a history of penicillin therapy for syphilis, 5 had received heavy metal therapy, and 27 had no history of syphilis. These 39 patients had a neurological examination, serum VDRL, Treponema pallidum immobilization (TPI), and repeat FTA-ABS tests by two other laboratories. The TPI test was reactive in 30 (77%). Four had nonspecific neurological signs. Routine CSF examination (cells, total protein, VDRL, glucose, IgG%) on 30 patients with a history of inadequate treatment had a low diagnostic yield. Two patients had an unexplained total protein elevation (57 and 61 mg/dl) and 1 had a mildly increased IgG% (15%). All cell counts, VDRL tests, and glucose levels were normal. Agarose electrophoresis demonstrated one or more CSF immunoglobulin bands in 10 (36%) of 28 patients, possibly representing an immunological marker of past or latent central nervous system infection.