Immunohistochemical localization of glutathione-S-transferase and glutathione peroxidase in adult Syrian hamster tissues and during kidney development.

Tissues from adult Syrian hamsters were studied with immunoperoxidase techniques using polyclonal antibodies to glutathione-S-transferase (rat liver and human placental enzymes) and human erythrocyte glutathione peroxidase. Most tissues immunostained similarly with these antibodies. Most notable was the cytoplasmic staining of mesenchyme tissues, especially smooth muscle, by all three antibodies. Epithelial cells stained distinctively, but usually less intensely than mesenchyme. Epithelial cells from all levels of the gastrointestinal tract, respiratory epithelium, transitional epithelium, and epidermis all showed strong staining with these antibodies. Other epithelial cell types were usually positive but showed less dramatic staining. Most epithelial tissues showed both nuclear and cytoplasmic staining; some also showed cell-surface (eg, cilia) staining. The role of these enzymes in cell differentiation of a stable organ was studied by immunostaining the kidney during its development. Early stroma (13- and 15-day fetuses) of the kidney (metanephric mesenchyme) showed strong cell-surface staining for glutathione transferases and moderate staining for glutathione peroxidase; renal tubules (which are epithelial cells) at this stage were negative for these markers. As renal tubules differentiated, first cytoplasm and then nuclei stained moderately, suggesting that glutathione-S-transferases and glutathione peroxidase are markers of both mesenchymal cells, including embryonic mesenchyme, and terminal differentiation of at least some epithelial cells.     

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.     

An attempt to treat rabies encephalitis in monkeys with intrathecal live rabies virus RV 675

Summary A highly attenuated rabies virus, RV 675, proved innocuous but immunogenic when injected intrathecally into monkeys by the lumbar route. Attempts to use this virus to modify the course of fatal rabies encephalitis in monkeys were inconclusive possibly because of the brief encephalitic illness. Further studies are indicated to investigate RV 675 as a candidate therapeutic agent for rabies encephalitis.     

Lipopolysaccharide augments IgG and IgE responses of mice to the latex allergen Hev b 5

Background: LPS is a common contaminant in the health care environment and in latex examination gloves. Objective: We sought to investigate the role of LPS in enhancing the immune responses of mice to inhaled latex allergen. Methods: As our model allergen, we used a fusion protein containing the potent latex allergen Hev b 5. BALB/c mice were lightly anesthetized and given repeated intranasal doses of saline, LPS, and/or Hev b 5. The doses were given in 2 courses separated by a 6-week period, with the first course consisting of 6 doses and the second consisting of 3 doses. Results: After the first set of immunizations, mice given Hev b 5 alone had no detectable IgG1 or IgE responses to Hev b 5, whereas mice given the antigen along with LPS had significant responses (IgG1, 0.73 U ± 0.05; IgE, 0.88 U ± 0.2). No enhancement of specific IgG2a was observed. A stimulatory effect of LPS on all 3 immunoglobulin types was apparent after the second course. Lymphocytes from mice immunized with LPS and Hev b 5 had increased proliferation to Hev b 5 and its fusion partner. Conclusions: LPS may be an important immunoadjuvant for the development of allergic reactions to latex protein allergens. (J Allergy Clin Immunol 199;102:977-83.)     

Noninvasive measurement of human forearm oxygen consumption by near infrared spectroscopy

Summary This study reported on the application of near infrared spectroscopy (NIRS) to noninvasive measurements of forearm brachio-radial muscle oxygen consumption ( O₂) and recovery time (t _r) in untrained volunteers. Seven healthy subjects were submitted to four consecutive protocols involving measurements made at rest, the induction of an ischaemia, and during a maximal increase of metabolic demand achieved with and without vascular occlusion. Two isometric maximal voluntary contractions (MVC) of 30-s duration were executed with and without vascular occlusion and a 50% MVC lasting 125 s was also performed. The protocols were repeated on 2 different days. The results showed that, during vascular occlusion at rest, the time to 95% of the final haemoglobin (Hb) + myoglobin (Mb) desaturation value was independent of O₂. The MVC, performed during vascular occlusion, caused complete Hb + Mb desaturation in 15–20 s, which was not followed by any further desaturation when the second contraction was performed. No difference was found between O₂during MVC with and without vascular occlusion. A consistent difference was seen between O₂measured during occlusion at rest and O₂measured during MVC with and without occlusion. During prolonged exercise (125 s) Hb + Mb desaturation was maintained for the whole contraction period. The results of this study show that O₂can be measured noninvasively by NIRS. The O₂during MVC was very similar both in the presence and absence of blood flow limitation in most of the subjects tested. This would suggest that muscle O₂might be accurately evaluated dynamically without cuff occlusion.     

Measurement of changes in cytochrome oxidase redox state during obstructive sleep apnea using near-infrared spectroscopy

STUDY OBJECTIVES: To use near-infrared spectroscopy to investigate the effect of obstructive sleep apnea on cytochrome oxidase, the terminal enzyme of the mitochondrial respiratory chain. DESIGN: Observational study. SETTING: Teaching hospital sleep unit. PATIENTS: Subjects with diagnosed moderate to severe obstructive sleep apnea were recruited from the sleep clinic. INTERVENTIONS: Subjects were invited to attend 2 daytime sleep-study sessions, which included near-infrared monitoring of cerebral oxygenation and cytochrome-oxidase oxidation state. In addition, in study session 1, full polysomnography was performed (8 subjects, 303 apneas), and in study session 2, arterial oxygen saturation, cerebral blood flow velocity, and blood pressure were monitored (7 subjects, 287 apneas). MEASUREMENTS AND RESULTS: In study session 1, mean (+/- SD) cytochrome-oxidase changes ranged from 0.48 +/- 0.08 microM to 0.13 +/- 0.05 microM. The magnitude of cytochrome-oxidase change correlated significantly with the magnitude of change in the cerebral tissue oxygenation index (P < .001). In study session 2, there were significant correlations between arterial oxygen-saturation changes and cytochrome-oxidase redox changes and between Doppler cerebral blood flow velocity changes and cytochrome-oxidase redox changes (P < .001 and P = .001, respectively). CONCLUSIONS: Changes in directly measured cerebral tissue saturation and changes in arterial saturation and cerebral blood flow velocity (the 2 main factors affecting cerebral oxygenation) are associated with changes in cytochrome-oxidase oxidation state. The reduced cerebral oxygenation that occurs during obstructive sleep apnea is associated with changes in the intracellular redox state.     

Distal rectus femoris surgery in children with cerebral palsy: results of a Delphi consensus project

PurposeThe purpose of this study was for an international panel of experts to establish consensus indications for distal rectus femoris surgery in children with cerebral palsy (CP) using a modified Delphi method.MethodsThe panel used a five-level Likert scale to record agreement or disagreement with 33 statements regarding distal rectus femoris surgery. The panel responded to statements regarding general characteristics, clinical indications, computerized gait data, intraoperative techniques and outcome measures. Consensus was defined as at least 80% of responses being in the highest or lowest two of the five Likert ratings, and general agreement as 60% to 79% falling into the highest or lowest two ratings. There was no agreement if neither threshold was reached.ResultsConsensus or general agreement was reached for 17 of 33 statements (52%). There was general consensus that distal rectus femoris surgery is better for stiff knee gait than is proximal rectus femoris release. There was no consensus about whether the results of distal rectus femoris release were comparable to those following distal rectus femoris transfer. Gross Motor Function Classification System (GMFCS) level was an important factor for the panel, with the best outcomes expected in children functioning at GMFCS levels I and II. The panel also reached consensus that they do distal rectus femoris surgery less frequently than earlier in their careers, in large part reflecting the narrowing of indications for this surgery over the last decade.ConclusionThis study can help paediatric orthopaedic surgeons optimize decision-making for, and outcomes of, distal rectus femoris surgery in children with CP.Level of evidenceV     

Comparative Carcinogenicity of 5,5-Diphenylhydantoin with or without Perinatal Exposure in Rats and Mice

Volume 21, Number 2 (1993), in the article "Comparative Carcinogenicityof 5,5-Diphenyihydantoin with or without Perinatal Exposurein Rats and Mice," by R. S. Chhabra, J. R. Bucher, J. K. Haseman,M. R. Elwell, P. J. Kurtz, and B. D. Canton, pages 174–186:Since the publication of the above article, the authors havefound that the feed and estimated DPH consumption data reportedin Tables 2 and 6 were incorrect. The following Tables 2 and6 contain revised feed and DPH consumption data:     

The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies

The objective of this study was to examine the effects of the intakeof dietary fat upon colorectal cancer risk in a combined analysis of datafrom 13 case-control studies previously conducted in populations withdiffering colorectal cancer rates and dietary practices. Original datarecords for 5,287 cases of colorectal cancer and 10,470 controls werecombined. Logistic regression analysis was used to estimate odds ratios (OR)for intakes of total energy, total fat and its components, and cholesterol.Positive associations with energy intake were observed for 11 of the 13studies. However, there was little, if any, evidence of anyenergy-independent effect of either total fat with ORs of 1.00, 0.95, 1.01,1.02, and 0.92 for quintiles of residuals of total fat intake (P trend =0.67) or for saturated fat with ORs of 1.00, 1.08, 1.06, 1.21, and 1.06 (Ptrend = 0.39). The analysis suggests that, among these case-control studies,there is no energy-independent association between dietary fat intake andrisk of colorectal cancer. It also suggests that simple substitution of fatby other sources of calories is unlikely to reduce meaningfully the risk ofcolorectal cancer.