Carbohydrate feeding and exercise: effect of beverage carbohydrate content

Summary The purpose of this study was to determine the effect of ingesting fluids of varying carbohydrate content upon sensory response, physiologic function, and exercise performance during 1.25 h of intermittent cycling in a warm environment (T _db=33.4°C). Twelve subjects (7 male, 5 female) completed four separate exercise sessions; each session consisted of three 20 min bouts of cycling at 65% , with each bout followed by 5 min rest. A timed cycling task (1200 pedal revolutions) completed each exercise session. Immediately prior to the first 20 min cycling bout and during each rest period, subjects consumed 2.5 ml·kg BW⁻¹ of water placebo (WP), or solutions of 6%, 8%, or 10% sucrose with electrolytes (20 mmol·l⁻¹ Na⁺, 3.2 mmol·l⁻¹ K⁺). Beverages were administered in double blind, counterbalanced order. Mean (±SE) times for the 1200 cycling task differed significantly: WP=13.62±0.33 min, *6%=13.03±0.24 min, 8%=13.30±0.25 min, 10%=13.57±0.22 min (*=different from WP and 10%,P<0.05). Compared to WP, ingestion of the CHO beverages resulted in higher plasma glucose and insulin concentrations, and higher RER values during the final 20 min of exercise (P<0.05). Markers of physiologic function and sensory perception changed similarly throughout exercise; no differences were observed among subjects in response to beverage treatments for changes in plasma concentrations of lactate, sodium, potassium, for changes in plasma volume, plasma osmolality, rectal temperature, heart rate, oxygen uptake, rating of perceived exertion, or for indices of gastrointestinal distress, perceived thirst, and overall beverage acceptance. Compared to ingestion of a water placebo, consumption of beverages containing 6% to 10% sucrose resulted in similar physiologic and sensory response, while ingestion of the 6% sucrose beverage resulted in significantly improved end-exercise performance following only 60 min of intermittent cycling exercise.     

Temporal pattern of herpes simplex virus type 1 infection and cell death in the mouse brain stem: influence of guanosine nucleoside analogues

Levels of bystander death occurring in herpes simplex virus type 1 (HSV-1)-infected mouse brain stems were studied, as well as the extent to which bystander death is influenced by guanosine nucleoside analogue treatment. Consecutive sections from brain stems of HSV-1-infected mice were stained alternately for (i) viral infection and (ii) cell death (TUNEL assay). Virus antigen was detectable in brain stems on day 3 of infection, while TUNEL staining was comparatively lower. An increase in the extent of TUNEL staining was observed on day 4 of infection. Despite this increase, however, the ratio of TUNEL-stained to infection marker-stained tissue still indicated that the amount of TUNEL staining remained lower than infection staining at this time point. On days 5 and 6 of infection, TUNEL staining continued to increase and the TUNEL/infection marker ratio switched on day 6 in favour of excess TUNEL staining, which was observed in and around the foci of infection, suggesting bystander death. The excess TUNEL staining on day 6 of infection was further increased on treatment with antivirals. The significance and implications of these results are discussed with respect to the nature and mechanism of action of the TUNEL assay, dynamics of primary HSV-1 infection, immunological influences and potential effects of antiviral treatment. The potential problems of the TUNEL assay are considered in the context of viral infection and the TUNEL assay, in combination with infection marker staining, may potentially provide a model system for quantitative analysis of true bystander death during HSV infection in vivo.     

Virulence alterations of Tacaribe virus infection in adult mice: Lethal model for encephalitis

Summary Selection of populations of Tacaribe virus strain 11573 lethal for mice was carried out by serial intracerebral passage of the virus in adult mice. Viral populations have been characterized by determination of virulence for suckling, weanling, and adult mice, and by histopathologic changes observed in brains of adult mice after intracerebral inoculation. Some of the virus preparations produced 80 to 90 per cent mortality after two or three intracerebral passages in adult mice and maintained this virulence for 1 to 3 passages, after which the virulence rapidly declined with subsequent passages. Clinical signs of infection in adult mice were manifested by a rough hair-coat, ventriflexed posture, diminished activity, increased excitability, flaccid hind-limb extension with progressive paralysis and death. Histologic examination revealed meningoencephalitis.With 2 FiguresIn conducting the research described in this report, the investigators adhered to the Guide for the Care and Use of Laboratory Animals, as promulgated by the Committee on the Revision of the Guide for Laboratory Animal Facilities and Care of the Institute of Laboratory Animal Resources, National Research Council. The facilities are fully accredited by the American Association for Accreditation of Laboratory Animal Care.The views of the authors do not purport to reflect the positions of the Department of the Army or the Department of Defense.     

Analysis of western blotting (immunoblotting) technique in diagnosis of congenital syphilis.

The diagnosis of congenital syphilis in apparently healthy infants continues to be problematic. Immunoglobulin M antibodies specific for a subset of Treponema pallidum antigens have been detected by Western blotting (immunoblotting). In the present study we investigated the sensitivity and specificity of this method. We tested 26 infants aged 0 to 4 months who fulfilled the accepted criteria for the diagnosis of congenital syphilis. There were 14 symptomatic infants. Sera from 13 of these infants were positive for the 47-kDa treponemal antigen (92% sensitivity). The remaining 12 infants were clinically asymptomatic when tested at birth but subsequently displayed features consistent with the disease. Reactive blots (antibodies to the 47- and/or the 15-kDa antigens) were noted in 10 of the 12 infants (83% sensitivity). Thirty infants whose mothers had syphilis were monitored and shown to be uninfected. Nonreactive blots were seen in sera from 27 infants, while sera from 3 older infants had false-positive tests (90% specificity). The Western blotting technique is sensitive (even in the diagnosis of clinically inapparent cases) and, in the absence of immunoglobulin M rheumatoid factor, is a useful confirmatory test for congenital syphilis.     

The phage T4 nrdB intron: a deletion mutant of a version found in the wild

Bacteriophage T4 possesses three self-splicing group I introns. Two of the three introns are mobile elements; the third, in the gene encoding a subunit of the phage nucleotide reductase (nrdB), is not mobile. Because intron mobility offers a reasonable explanation for the paradoxical occurrence of large intervening sequences in a space-efficient eubacterial phage, it is puzzling that the nrdB intron is not mobile like its compatriots. We have discovered a larger nrdB intron in a closely related phage, and we infer from comparative sequence data that the T4 intron is a deletion mutant derived from this larger intron. This larger nrdB intron encodes an open reading frame of 269 codons, which we have cloned and overexpressed. The overexpressed protein shows a dsDNA endonuclease activity specific for the intronless nrdB gene, typical of mobile introns. Thus, we believe that all three introns of T4 are or were mobile "infectious introns" and that they have entered into and been maintained in the phage population by virtue of this efficient mobility.     

Immunological Studies on the Envelope Component of Venezuelan Equine Encephalomyelitis Virus

Treatment of purified Venezuelan equine encephalomyelitis virus with the nonionic detergent Triton X-100 permitted spearation of the envelope from the core component. The isolated envelope was a noninfectious immunogen which reacted in hemagglutination, hemagglutination inhibition, complement fixation, and neutralization serological reactions.     

Improved method for production of attenuated Venezuelan equine encephalomyelitis (TC-83 strain) vaccine.

Primary chicken embryo cell cultures were evaluated a s an alternate cell system for the production of attenuated Venezuelan equine encephalomyelitis (TC-83 strain) vaccine. The TC-83 strain virus was shown to remain stable during 10 serial passages in chicken embryo cell culture with regard to plaque size and morphology, virus yield, potency, and virulence for mice and hamsters.     

Phase I and pharmacokinetic study of tiazofurin (TCAR,NSC 286193) administered by continuous infusion

Summary Tiazofurin (2--D-ribofuranosylthiazole-4-carboxamide, TCAR) is a synthetic C-nucleoside that demonstrated significant in vivo activity against a variety of animal tumors as well as in vitro activity against human tumor-derived cell lines. Thirteen patients were treated with TCAR administered as a 5-day continuous infusion in this Phase I trial. Seventeen complete cycles were administered in three dose levels ranging from 550 to 1450 mg/M². Dose-limiting toxicities were myelosuppression and neurotoxicity including severe lethargy. Other toxicities including superficial skin peeling, myalgias, and tearing were seen at all doses. One patient had chest pain on day 4 resulting in stopping the drug, however, there was no evidence of cardiac or pericardial disease. Uric acid levels rose within one day in the absence of allopurinol treatment. There were no treatment related deaths. HPLC measurement of drug levels demonstrated steady-state plasma levels during the infusion, and a half-life following the infusion of 7.7 ± 0.6 hours. Minor abnormalities in renal function were associated with dramatic changes in pharmacokinetics and toxicity. No clinical responses were observed in this trial.Abbreviations TCAR Tiazofurin - HPLC High performance liquid chromatography - IMPD Inosine monophosphate dehydrogenase - WBC white blood cell - CPK creatine phosphokinase - C_ss steady-state concentration     

Recovery of motor and language abilities after stroke: the contribution of functional imaging

In recent years, functional imaging techniques, like functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and transcranial magnetic stimulation (TMS), have shown that the improvement of motor and language function after ischemic stroke is accompanied by extensive reorganizational changes in the human cortex. To better understand these changes and to judge to what extent they could be responsible for clinical improvement, some basic principles of the organization of the motor and language system are discussed.Non-invasive functional imaging can have only a limited contribution in determining which of the possible underlying neural mechanisms, as they are known from animal experiments, play a role in functional recovery. However, they make it possible to define the functional consequences of anatomical lesions in individual patients and to correlate these functional consequences in the motor and language system with the clinical deficit. They can be used to assess the influence on the cortical reorganization of established and newer physiotherapies, logopedics and medical intervention, and they could be a useful tool in determining prognosis.