Arterial oxygen desaturation during moderate hypoxia hinders sensorimotor performance.

INTRODUCTION: Moderate hypoxia may impact cognitive and sensorimotor performance prior to self-recognized impairments. Therefore, rapid and objective assessment tools to identify people at risk of impaired function during moderate hypoxia is needed. PURPOSE: Test the hypothesis that reductions in arterial oxygen saturation during moderate normobaric hypoxia (FiO2 = 14%) decreases gamified sensorimotor performance as measured by alterations of motor acuity. METHODS: Following three consecutive days of practice, thirty healthy adults (25 ± 5 y, 10 females) completed three bouts of the tablet-based gamified assessment (Statespace Labs, Inc.) of motor acuity at Baseline and 60 and 90 min after exposure to 13.8 ± 0.2% (hypoxia) and 20.1 ± 0.4% (normoxia) oxygen. The gamified assessment involved moving the tablet to aim and shoot at targets. Both conditions were completed on the same day and were administered in a single-blind, block randomized manner. Performance metrics included shot time and shot variability. Arterial oxyhemoglobin saturation estimated via forehead pulse oximetry (SpO2). Data were analyzed using linear mixed effects models. RESULTS: Compared to normoxia (99±1%), SpO2 was lower (p<0.001) at 60 (89±3%) and 90 (90±2%) min of hypoxia. Shot time was unaffected by decreases in SpO2 (0.012, p = 0.19). Nor was shot time affected by the interaction between SpO2 decrease and baseline performance (0.006, p = 0.46). Shot variability was greater (i.e., less precision, worse performance) with decreases in SpO2 (0.023, p = 0.02) and depended on the interaction between SpO2 decrease and baseline performance (0.029, p< 0.01). CONCLUSION: Decreases in SpO2 during moderate hypoxic exposure hinders sensorimotor performance via decreased motor acuity, i.e., greater variability (less precision) with no change in speed with differing decreases in SpO2. Thus, personnel who are exposed to moderate hypoxia and have greater decreases in SpO2 exhibit lower motor acuity, i.e., less precise movements even though decision time and movement speed are unaffected.

Gamified assessment of cognitive performance during moderate hypoxia.

INTRODUCTION: There is a need for rapid and objective assessment tools to identify people at risk of impaired cognitive function during hypoxia. PURPOSE: To test the hypotheses that performance on gamified cognitive tests examining the cognitive domains of executive function (Gridshot), working memory (Capacity) and spatial tracking (Multitracker) will be reduced during normobaric exposure to moderate normobaric hypoxia. METHODS: Following three consecutive days of practice, twenty-one healthy adults (27 ± 5 y, 9 females) completed five 1-min rounds of the tablet-based games Gridshot, Capacity, and Multitracker (Statespace Labs, Inc.) at Baseline and 60 and 90 min after exposure to 14.0 ± 0.2% (hypoxia) and 20.6 ± 0.3% (normoxia) oxygen. Both conditions were completed on the same day and were administered in a single-blind, block randomized manner. Arterial oxyhemoglobin saturation was estimated via forehead pulse oximetry (SpO2). Data were analyzed using ANCOVA with a covariate of Baseline. RESULTS: Compared to normoxia (98 ± 1%), SpO2 was lower (p < 0.001) at 60 (91 ± 3%) and 90 (91 ± 2%) min of hypoxia. No condition x time interaction effects were identified for any gamified cognitive tests (p ≥ 0.32). A main effect of condition was identified for Capacity (p = 0.05) and Multitracker (p = 0.04), but not Gridshot (p = 0.33). Post hoc analyses of the composite scores for both Capacity (p = 0.11) and Multitracker (p = 0.73) demonstrated no difference between conditions. CONCLUSION: Performance on gamified cognitive tests was not consistently affected by acute normobaric moderate hypoxic exposure.

Formulation development and human in vitro-in vivo correlation for a novel, monolithic controlled-release matrix system of high load and highly water-soluble drug niacin.

Novel, controlled-release formulations for high drug load, highly water soluble compound niacin based on polyethylene oxide (PEO) and hydroxypropylmethyl cellulose (HPMC) matrices were developed and investigated. The effect of sodium bicarbonate as a modulator of swelling, erosion, and drug release and its impact on changes in the kinetics of axial swelling and gel strength were evaluated by textural analysis during dissolution study. The drug release rate from PEO-based matrices was faster and correlated with lower gel strength, greater water uptake, and greater matrix erosion. Slower release rate and greater release duration correlated significantly with greater matrix swelling with negligible matrix erosion for the HPMC-based matrix system. Inclusion of sodium bicarbonate in the polymeric matrix salted out the macromolecules and increased gel strength and gel viscosity, especially in the vicinity of the swelling fronts. An in vivo study in human subjects after administration of the formulations and a commercial product exhibited similar plasma concentrations. For the formulation of interest, the mean drug fraction absorbed by the body was calculated by the Wagner-Nelson technique, and a level A "in vitro-in vivo correlation" was observed between the percent released in vitro and percent absorbed in vivo. The developed formulations appear to be robust and easy to manufacture with maximum flexibility with respect to drug dose, polymeric carriers, duration, and kinetics of drug release.

Ecology of Vibrio vulnificus in estuarine waters of eastern North Carolina.

While several studies on the ecology of Vibrio vulnificus in Gulf Coast environments have been reported, there is little information on the distribution of this pathogen in East Coast waters. Thus, we conducted a multiyear study on the ecology of V. vulnificus in estuarine waters of the eastern United States, employing extensive multiple regression analyses to reveal the major environmental factors controlling the presence of this pathogen, and of Vibrio spp., in these environments. Monthly field samplings were conducted between July 2000 and April 2002 at six different estuarine sites along the eastern coast of North Carolina. At each site, water samples were taken and nine physicochemical parameters were measured. V. vulnificus isolates, along with estuarine bacteria, Vibrio spp., Escherichia coli organisms, and total coliforms, were enumerated in samples from each site by using selective media. During the last 6 months of the study, sediment samples were also analyzed for the presence of vibrios, including V. vulnificus. Isolates were confirmed as V. vulnificus by using hemolysin gene PCR or colony hybridization. V. vulnificus was isolated only when water temperatures were between 15 and 27 degrees C, and its presence correlated with water temperature and dissolved oxygen and vibrio levels. Levels of V. vulnificus in sediments were low, and no evidence for an overwintering in this environment was found. Multiple regression analysis indicated that vibrio levels were controlled primarily by temperature, turbidity, and levels of dissolved oxygen, estuarine bacteria, and coliforms. Water temperature accounted for most of the variability in the concentrations of both V. vulnificus (47%) and Vibrio spp. (48%).

The implementation of a new method of student assessment in a pathogenic bacteriology laboratory course.

A new case study method of assessment was developed to challenge advanced undergraduate biology majors interested in medical careers and allied health professions. This method is an alternative to traditional "unknown" identifications used in many microbiology laboratories. Students used various biochemical tests and selective media throughout the course to identify organisms cultured from their own bodies. In preparing a final assessment for the course, an assignment was developed to challenge the students to apply what they had learned in a medically relevant setting. Also of importance was the elimination of further biochemical testing by these students and prevention of contact with strict pathogens in this lab, due to budget and safety constraints, respectively. Each student was provided with a clinical specimen data record sheet and additional information about their "diseased patient". Students used analytical skills and critical thinking, as well as knowledge gained throughout the semester, to logically deduce the causative agent of disease in the mock patients. Students were required to: (i) describe the steps in this logical deduction, (ii) provide a brief overview of the characteristics and virulence factors of the organism(s), (iii) investigate all disease(s) caused by the organism, (iv) describe symptomology of the patient in detail, and (v) investigate disease treatment and prevention methods. The final assignment involved library and Internet research and culminated in a written report, which further developed writing and communication skills. Detailed descriptions of and materials for this assignment are provided along with an overall evaluation of this method after implementation.

U.S. Air force recruit injury and health study.

OBJECTIVES: To assess the types, rates, and risks of injury for male and female USAF recruits. DESIGN: Outpatient visits for female (5250) and male recruits (8656) were collected and analyzed for rate of injury, types of injuries, and risk of injury throughout a 6-week training period. RESULTS: One third of female recruits and one sixth of male recruits were injured at least once during recruit training. The overall rate for injuries in women and men was 63.0 and 27.8 per 1000 person-weeks, respectively. The adjusted relative risk for women versus men for all injuries was 2.22, and was consistent (1.67 to 3.27) across injury sites. Despite declining absolute rates of injury by week (106.1-13.4 for women and 53.7-13.2 for men), relative risk of injury for women versus men remained fairly constant throughout each training week. The relative risk for injury serious enough to result in medical hold was 1.69 for women vis-a-vis men. Approximately half of all medical discharges for women and men were for injuries. CONCLUSIONS: Female recruits were injured twice as often as male recruits, and were 1.5 times more likely to be removed from their training cohort for injury. Relative risk for injuries to specific body areas remained fairly consistent, indicating that no gender-specific injuries were occurring. Further efforts to determine the cause of injuries should be undertaken, and interventions aimed at reducing the disparate risk of injuries in women should be developed and evaluated.

Effects of the benzodiazepine inverse agonist RO19-4603 alone and in combination with the benzodiazepine receptor antagonists flumazenil, ZK 93426 and CGS 8216, on ethanol intake in alcohol-preferring (P) rats.

The present study investigated dose dependence and time course effects of the benzodiazepine (BDZ) partial inverse agonist, RO19-4603 (0.005-0.30 mg/kg) alone, and in combination with the BDZ receptor antagonists flumazenil, ZK 93426, and CGS 8216 (20 mg/kg) in selectively bred alcohol-preferring (P) rats provided a two-bottle choice test between ethanol (EtOH) (10% v/v), and a palatable saccharin (0.0125% g/v) solution. A single dose of RO19-4603 as low as 0.009 mg/kg selectively reduced EtOH drinking during the initial 15 min of a 4 h access to 19-0% of control levels on day 1. The 0.08, 0.15 and 0.30 mg/kg doses of RO19-4603 significantly reduced total EtOH intake in the 4 h access period to 57-45% of controls on day 1. On day 2, no RO19-4603 injections were given; however, six of the seven doses of RO19-4603 (0.009, 0.02, 0.04, 0.08, 0.15, and 0.30 mg/kg) continued to reduce EtOH intake to 42-3% of control levels at the initial 15 min interval, while the 0.005, 0.009, 0.08, and 0.30 mg/kg doses reduced total 4 h EtOH intake to 60-42% of controls. Saccharin intake was either not altered by RO19-4603 or showed increases during the initial 15 min intervals and the total 4 h sessions on days 1 and 2. Food intake was also unaffected by RO19-4603. The CGS 8216, but neither flumazenil nor ZK 93426, reliably reversed the RO19-4603-induced suppression of EtOH intake on days 1 and 2. That certain BDZ inverse agonists can attenuate motivated behavior for EtOH reinforcement over a prolonged time course may provide a possible therapeutic approach to reducing EtOH consumption associated with alcoholism.

Two-dimensional polyacrylamide gel electrophoretic characterization of proteins from organs of C3H mice expressing the scurfy (sf) genetic mutation during early and late stages of disease progression.

Scurfy (sf), is an X-linked recessive lethal mutation that occurs spontaneously in the C3H mouse. The disease is characterized by lymphoid and hematopoietic dysfunction. Affected males are of small stature and exhibit scaliness and crusting of the eyelids, ears, tail, and feet, marked splenomegaly, moderate hepatomegaly, enlarged lymph nodes, and atrophy of the thymus. The average lifespan of the affected hemizygous males (sf/y) is 24 +/- 0.7 days. Total cellular proteins were extracted from pooled samples of thymus and spleen obtained from combined litters of mice. Tissue-specific protein profiles characteristic of either sf mutant or normal mice were analyzed by two dimensional polyacrylamide gel electrophoresis (2DPAGE) at different stages of the phenotypic expression of the sf mutation, to identify changes in protein patterns that might be associated with the progression of the disease. The resultant gels were silver stained, digitized, and analyzed, by image analysis utilizing a pipelined image processor connected to a host computer. At 14 +/- 1 days of age, protein patterns from sf mutant and normal mice control organs showed considerable homogeneity, although there were proteins identified unique to the sf mutant and to the normal controls. At 20 +/- 1 days of age, the pattern differences between the sf mutant and normal control increased markedly. Differences were expressed as the percent of proteins that were unique to either the sf mutant or the normal control from the total number of each type. The percent of proteins that increased or decreased in the three organs utilized in this study ranged between 21%-39% at 14 days and were between 25%-54% at 20 days. Differences in protein expression between the normal and sf mutant as the disorder progressed for each of the three tissues examined. In addition, thymus protein profiles from 9 day old littermates that were phenotypically normal but genotypically unknown were evaluated to determine if marker proteins could be identified for the sf mutation. Limited protein changes were noted at relative molecular weights of 66, 60, 54, 39, 37, 33, 25, 23, 27, and 11 kDa. These data suggest that the sf mutation follows a trackable pattern of protein expression and repression different than the normal control C3H mouse. Several potential marker proteins associated with the sf mutation were identified in 9 day thymus prior to the phenotypic expression of the disease. These putative biomarkers may be useful for characterizing the sf mutation and the mutant may act a possible model the Wiskott-Aldrich syndrome (WAS).

Comparison of 14C-amino acid mixture and [35S]methionine labeling of cellular proteins from mouse fibroblast C3H10T1/2 cells by two-dimensional gel electrophoresis.

Total cellular proteins from mouse C3H10T1/2 fibroblasts were compared by two-dimensional (2-D) gel electrophoresis after radiolabeling with [35S]methionine (35S-Met) or 14C-amino acids (14C-AA). 35S-Met labeling of protein was three to four times greater than 14C-AA incorporation over a 24 h period. Automated comparative analysis of replicate fluorographs after 6, 12, and 24 h of labeling showed considerable homology between radiolabeling methods. More than 88% percent of 35S-Met and 14C-AA-labeled proteins were common at each time point. However, the total number of 35S-Met-labeled proteins dropped from 6 to 24 h while the number of 14C-AA-labeled proteins increased. Additionally, twenty-one proteins were uniquely labeled by 14C-AA that were not detectable by 35S-Met over the labeling period. Densitometric analysis showed that several 35S-Met and 14C-AA-labeled proteins exhibited time-related differences in radiolabel incorporation while most proteins remained relatively constant. Protein patterns of silver-stained gels from 6 to 24 h were highly registered and showed few qualitative differences. Proteins detected in radiolabeled gels were generally, but not always, found in silver-stained gels. Thus, 35S-Met appears better suited for short-term radiolabeling of cellular protein while more comprehensive labeling of protein occurs with 14C-AA during prolonged incubation of cell cultures under present experimental conditions.

Ganglioneuroma of the sacrum.

Ganglioneuromas (GNs) are benign, slow-growing, rare soft-tissue tumors that arise from the sympathetic nervous system and comprise less than 1% of all soft-tissue neoplasms. Although GNs are slow-growing, they can and will invade bone and pressure local adjacent structures by their continued growth. In a 20-year-old woman, GN produced a large presacral mass. This case illustrates the diagnostic features at various stages of growth, histopathology, and treatment of GN.

Leukotriene D4 antagonists and 5-lipoxygenase inhibitors. Synthesis of benzoheterocyclic [(methoxyphenyl)amino]oxoalkanoic acid esters.

A series of novel benzoheterocyclic [(methoxyphenyl)amino]oxoalkanoic acid esters has been prepared. These compounds were tested as inhibitors of rat polymorphonuclear leukocyte 5-lipoxgenase (LO) in vitro and as inhibitors of leukotriene D4 (LTD4) and ovalbumin (OA) induced bronchospasm in the guinea pig (GP) in vivo. In general, inhibitory activity against 5-LO, LTD4, and OA was broadest for benzthiazole-containing analogues (benzthiazole greater than benzimidazole much greater than benzoxazole, benzofuran). The most potent 5-LO inhibitor, 4-[[3-(2-benzthiazolylmethoxy)-phenyl]hydroxyamino]-4-oxobutanoic acid methyl ester (7), had an IC50 of 0.36 microM. Compound 7, however, was inactive vs. OA. The most potent compound in vivo, 4-[[3-[(1-methyl-2-benzimidazolyl)methoxy]phenyl]-amino] -4-oxobutanoic acid methyl ester 4, inhibited both LTD4- and OA-induced bronchospasm by 83% and 60%, respectively, at 50 mg/kg intraduodenally. Compound 4 was studied in the Ames assay employing five strains of bacteria (TA1535, TA1537, TA1538, TA98, and TA100) with and without S-9 rat liver enzyme metabolic activation, and there was no significant number of reversions noted.

Hazard evaluation of monochloroacetone.

Monochloroacetone was introduced in 1914 as a war gas, and presently it has a number of uses as a chemical intermediate. Apart from its biological properties as a lacrimator and vesicant, it is not a well-studied compound toxicologically. A series of acute toxicity studies were done using different routes of administration. An Ames mutagenicity test also was performed. These data were compared to manufacturing use information and data published in the literature. It is recommended that direct contact with liquid and vapor be prevented through strict engineering controls and that air concentrations be kept below 1 ppm as a ceiling concentration.

The effect of liver homogenate (S20) concentration on polycyclic aromatic hydrocarbon activation and mutation induction in the L5178Y mouse lymphoma mutation assay.

Hydrocarbon activation and mutation induction in the L5178Y mouse lymphoma mutation assay were studied as a function of the concentration of an exogenously added rat liver homogenate activation system (S20). Four polycyclic aromatic hydrocarbons were tested at constant dosage levels with 4 concentrations of S20 for ability to induce forward mutations at the thymidine kinase (TK) locus. With all 4 hydrocarbons, increasing S20 concentration resulted in a significant (p less than 0.001) decrease in mutation frequency and corresponding increase in survival. In the absence of S20, no significant mutation induction was observed. Within 5 min after the addition of S20 to a reaction mixture containing [3H]benzo[a]pyrene [B(a)P] (3 micrograms/ml) and appropriate cofactors, 70% of the B(a)P was metabolized with a high S20 concentration, whereas only 14% was metabolized with a low S20 concentration. In the absence of S20, the cells did not metabolize B(a)P. Incubation of B(a)P with a low concentration of S20 in the presence of calf thymus DNA (1.5 mg/ml) resulted in twice as much covalently bound B(a)P per mg DNA (33 pmoles/mg) as incubation with a high concentration of S20 (15 pmoles/mg). The amount of the major B(a)P-DNA adduct, (+/-)-7 beta,8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene-deoxyguanosine, per mg DNA was 5 times greater with low S20 concentration than with high (11.6 pmoles/mg and 2.1 pmoles/mg, respectively). These results suggest that the decrease in mutation frequency with high S20 concentrations results from the rapid oxidation of the hydrocarbon which reduces the opportunity for mutagenic derivatives that are formed from B(a)P to interact with DNA and induce mutation.

Acute toxicity of methyl fluorosulfonate (Magic Methyl).

Methyl fluorosulfonate (Magic Methyl), an active methylating agent used by research chemists, was studied for acute oral toxicity, acute inhalation toxicity, ocular irritation, and dermal irritation. This compound is very hazardous and may have been responsible for at least one human death. The results of these studies confirmed that Magic Methyl is markedly toxic by all routes studied and particularly by the inhalation route since the LC50 value for rats was found to be between 5 and 6 ppm.

Mutagenic evaluation of nitroparaffins in the Salmonella typhimurium/mammalian-microsome test and the micronucleus test.

Three nitroparaffins (nitroethane, 1-nitropropane, and 2-nitropropane) were studied in the Salmonella typhimurium/mammalian microsome (Ames) test, with and without microsomal activation systems. Nitroethane and 2-nitropropane also were studied in an in vivo mutagenic (micronucleus) test. These studies were undertaken because these solvents are widely used in the chemical and pharmaceutical industries and 2-nitropropane was reported to cause liver cancer in rats exposed by the inhalation route. Neither nitroethane nor 1-nitropropane was active in the Ames test with Salmonella tester-strains TA1537, TA92, TA98, or TA100. However, 2-nitropropane produced a significant increase in revertants in all of these tester strains, particularly strain TA100, where 3 microliter/plate doubled the number of revertants in the presence of microsomal enzymes. Negative results were obtained with both nitroethane and 2-nitropropane in micronucleus tests. These studies have shown that 2-nitropropane has the potential for causing point mutations in a microbial test system. However, this compound probably will not cause a chromosome mutation of the clastogenic type.

Effect of cage size on patterns of activity and health of beagle dogs.

Thirty-two male beagle dogs were assigned at random, 16 to standard size cages (30 X 30 X 30 inches) and 16 to large cages (90 X 30 X 30 inches) for a period of 13 weeks, and then were "crossed-over" for an additional period of 13 weeks. The dogs were observed daily and weighed weekly. Electrocardiographic and ophthalmologic examinations were made once and hematologic and biochemical measurements were made twice during the control period and at monthly intervals during the study. Photographs were taken of each dog every 60 seconds, 7 days a week, for about 8.5 hours each day. The film was processed and analyzed for the acf standing sitting, lying, or sleeping. In addition, dogs in the large cages were scored for the region (front, middle, or back) occupied. No statistically significant differences were found between dogs in the standard or large cages with respect to weight gain, percent of time standing, and percent of time sleeping. Statistically significant (p less than 0.05) differences were found for percent of time sitting (standard cages 12.7%; large cages 9.4%) and percent of time lying (standard cages 6.6%; large cages 8.3%); however, the differences were not large enough to be of any practical concern. Transient patterns of response over 13-week periods of the study were essentially the same (statistically verified) for dogs in either size cage. Also statistical results showed that there was no significant carryover (residual) effect associated with any of the parameters measured. No beneficial or adverse effects were noted that could be related to the size of the two cages. The size of the standard cage appeared adequate for laboratory beagle dogs and no advantage was found when the dogs were in larger cages with respect to behavior, patterns of activity, or health.