Physiological responses to repeated apneas in underwater hockey players and controls.

The aim of this study was to investigate the effects of short repeated apneas on breathing pattern and circulatory response in trained (underwater hockey players: UHP) and untrained (controls: CTL) subjects. The subjects performed five apneas (A1-A5) while cycling with the face immersed in thermoneutral water. Respiratory parameters were recorded 1 minute before and after each apnea and venous blood samples were collected before each apnea and at 0, 2, 5 and 10 minutes after the last apnea. Arterial saturation (SaO2) and heart rate were continuously recorded during the experiment. Before the repeated apneas, UHP had lower ventilation, higher P(ET)CO2 (p < 0.05) and lower P(ET)O2 than CTL (p < 0.001). After the apneas, the P(ET)O2 values were always lower in UHP (p < 0.001) than CTL but with no difference for averaged P(ET)CO2 (p = 0.32). The apnea response, i.e., bradycardia and increased mean arterial blood pressure, was observed and it remained unchanged throughout the series in the two groups. The SaO, decreased in both groups during each apnea but the post-exercise SaO2 values were higher in UHP after A2 to A5 than in CTL (p < 0.01). The post-apnea lactate concentrations were lower in UHP than in CTL. These results indicate that more pronounced bradycardia could lead to less oxygen desaturation during repeated apneas in UHP. The UHP show a specific hypoventilatory pattern after repeated apneas, as well as a more pronounced cardiovascular response than CTL. They indeed showed no detraining of the diving response.

Spatial and temporal gait variable differences between basketball, swimming and soccer players.

The gait variables of 10 swimmers, 10 basketball players, and 16 soccer players were compared. They were all male and right-handed. There was no statistical difference between the three groups in age, weight and height. Spatial and temporal gait variables were measured with the Bessou gait analyzer. In the swimmers group, the gait variables of the right side were not statistically different from those of the left side. The right propulsion double support duration, right cycle duration, and right late swing phase duration were respectively longer than those on the left side for the basketball players. The right propulsion double support duration, right step length, and right late swing phase duration were higher than those on the left side for the soccer players. Moreover, a discriminant analysis performed with the gait variables permitted significant differentiation between the three groups. In conclusion, both basketball and soccer players presented asymmetrical gait variables, that have never been previously reported in normal subjects, or in swimmers. These results suggest that the anticipatory postural adjustments programmed to be used just before a jump or a shoot influence the motor program of the spontaneous locomotion. These gait asymmetries could also be due to asymmetric muscle development.

Spatiotemporal gait parameters measured using the Bessou gait analyzer in 79 healthy subjects. Influence of age, stature, and gender. Study Group on Disabilities due to Musculoskeletal Disorders (Groupe de Recherche sur le Handicap de l'Appareil Locomoteur, GRHAL).

The Bessou gait analyzer provides quantitative measurements of spatiotemporal gait parameters. The purpose of this study was to determine whether and how these parameters are influenced by age, stature, and gender. Seventy-nine normal individuals (38 males aged 20 to 80 years and 41 females aged 20 to 80 years) were divided into ten-year age groups. Males and females were studied separately. In each subject, the Bessou gait analyzer was used to measure spatiotemporal gait parameters (spatial parameters: stride and step lengths; temporal parameters: cycle, stance and swing durations). Mean walking speed was calculated in each subgroup. In both males and females, all study parameter values were identical for the left and right sides. Females younger than 60 years had shorter stride and step lengths (M: 1.5 +/- 0.2 m; F: 1.3 +/- 0.1; p < 0.001) but faster pace values (M: 104.8 +/- 9.0 cycles/min; F: 115.6 +/- 7.6 cycles/min; p < 0.001) than males, and consequently mean walking speed was similar in females and males (M: 4.8 km/h +/- 0.8 km/h; F: 4.4 km/h +/- 0.6 km/h). In contrast, females older than 60 years walked at the same pace as males and consequently had slower walking speeds. Stride length was correlated with age, stature, and gender. However, age was correlated with stature, and only age and gender had independent effects on gait parameters in the multiple regression analysis. In subjects of similar age and gender, effects of stature may need to be taken into account.

Complete nucleotide sequence of a circular plasmid from the Lyme disease spirochete, Borrelia burgdorferi.

We have determined the complete nucleotide sequence of a small circular plasmid from the spirochete Borrelia burgdorferi Ip21, the agent of Lyme disease. The plasmid (cp8.3/Ip21) is 8,303 bp long, has a 76.6% A+T content, and is unstable upon passage of cells in vitro. An analysis of the sequence revealed the presence of two nearly perfect copies of a 184-bp inverted repeat sequence separated by 2,675 bp containing three closely spaced, but nonoverlapping, open reading frames (ORFs). Each inverted repeat ends in sequences that may function as signals for the initiation of transcription and translation of flanking plasmid sequences. A unique oligonucleotide probe based on the repeated sequence showed that the DNA between the repeats is present predominantly in a single orientation. Additional copies of the repeat were not detected elsewhere in the Ip21 genome. An analysis for potential ORFs indicates that the plasmid has nine highly probable protein-coding ORFs and one that is less probable; together, they occupy almost 71% of the nucleotide sequence. Analysis of the deduced amino acid sequences of the ORFs revealed one (ORF-9) with features in common with Borrelia lipoproteins and another (ORF-2) having limited homology with a replication protein, RepC, from a gram-positive plasmid that replicates by a rolling circle (RC) mechanism. Known collectively as RC plasmids, such plasmids require a double-stranded origin at which the Rep protein nicks the DNA to generate a single-stranded replication intermediate. cp8.3/Ip21 has three copies of the heptameric motif characteristically found at a nick site of most RC plasmids. These observations suggest that cp8.3/Ip21 may replicate by an RC mechanism.

The efficacy of mineral oil combined with feed restriction in enhancing the elimination of heptachlor epoxide from mink (Mustela vison).

Adult female mink previously fed diets containing 0 (control) and 6.25 mg heptachlor/kg diet for 181 days were fed either the same control diet ad libitum (AL) or the control diet containing 10% mineral oil and restricted by 45% of ad libitum intake (MO/R) for 21 days to determine the efficacy of the latter treatment in enhancing the elimination of heptachlor epoxide (HE) from mink. Kit mink (2-3 months of age) whelped by dams of the control and 6.25 mg/kg groups were also fed the MO/R or AL diets for 21 days. Daily consumption (g/kg bw/day) of the AL diet by kit mink was significantly greater than consumption of the same diet by the adult females. Body weights of the control adults and the control and 6.25 mg/kg kits were significantly reduced by feeding the MO/R diet. Two adults from the control group and one adult from the 6.25 mg/kg group fed the MO/R diet died during the 21-day period. No mortalities occurred in kit mink fed either diet. Administration of the MO/R diet caused a significant reduction in body fat of the control adults and kits, but not in the 6.25 mg/kg adults and kits. Decreases in body fat of the MO/R groups were not associated with greater elimination of HE when compared to the AL groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Borrelia burgdorferi is clonal: implications for taxonomy and vaccine development.

The chromosomal genes fla and p93 and the ospA gene from a linear plasmid were sequenced from up to 15 isolates of Borrelia burgdorferi, which causes Lyme borreliosis in man. Comparison of the gene trees provides no evidence for genetic exchange between chromosomal genes, suggesting B. burgdorferi is strictly clonal. Comparison of the chromosomal gene trees with that of the plasmid-encoded ospA reveals that plasmid transfer between clones is rare. Evidence for intragenic recombination was found in only a single ospA allele. The analysis reveals three common clones and a number of rare clones that are so highly divergent that vaccines developed against one are unlikely to provide immunity to organisms from others. Consequently, an understanding of the geographic and genetic variability of B. burgdorferi will prove essential for the development of effective vaccines and programs for control. While the major clones might be regarded as different species, the clonal population structure, the geographic localization, and the widespread incidence of Lyme disease suggest that B. burgdorferi should remain the name for the entire array of organisms.

The reproductive effects of dietary heptachlor in mink (Mustela vison).

Adult female mink were fed diets containing 0 (control), 6.25, 12.5, and 25 ppm (micrograms/g) technical grade heptachlor prior to and throughout the reproductive period (181 days) to evaluate the effects of heptachlor consumption on reproduction and offspring viability and to assess the extent of placental and mammary transfer of heptachlor epoxide to mink offspring. Feeding 12.5 and 25 ppm resulted in significant reductions in feed consumption and body weights of female mink. Mortality was 0, 8, 67, and 100% for the control, 6.25, 12.5, and 25 ppm groups, respectively. All females in the 25 ppm group died within 88 days. Mink fed the two higher heptachlor diets displayed clinical signs indicative of central nervous system involvement just prior to death. Females were mated with males on the same dietary treatments. Whelping success rates were 67, 83, 27, and 0% for the control, 6.25, 12.5, and 25 ppm groups, respectively. High mortality in the 12.5 and 25 ppm groups accounted for the lack of reproductive success. Gestation length, litter size and birth weight of kits were not significantly affected by adult female consumption of 6.25 ppm heptachlor while kits helped by females on the 12.5 ppm diet weighed significantly less than control kits at birth. Survival of kits in the 12.5 ppm group from birth to three weeks of age was also adversely affected. At three and six weeks of age, kit body weights in both the 6.25 and 12.5 ppm groups were significantly less than body weights in control kits.(ABSTRACT TRUNCATED AT 250 WORDS)

Elimination of PBBs in rats. Effect of mineral oil and/or feed restriction.

Rats were fed polybrominated biphenyls (PBBs) at 0.1 to 100.0 ppm for 14 d and then treated to hasten the removal of PBBs with 0, 5, or 10% mineral oil (MO) and/or 0, 15, 30, or 45% feed restriction (FR) for 21 d. PBB body burdens were determined at d 14 and expressed on a log-log basis by Y = 0.91X + 2.179 (r2 = 0.974), where X = log of PBB concentration in diet (ppm) and Y = log of PBB body burden (micrograms). After 21 d withdrawal, body burdens were expressed by the equation Y = 0.787X + 2.218 (r2 = 0.95). The most effective withdrawal treatment was 10% MO + 45% FR producing a reduction of body burdens inversely related to prior body burdens (69% at 0.1 ppm to 23% at 100 ppm). Body weights and fat content were significantly (p less than or equal to .05) reduced by feed restriction, with fat content only 39% of controls at 21 d off. Mortality averaged 0, 13.6, and 35.8% for rats fed 0, 5, or 10% MO, and 25, 15, 8.6, and 3.7% for rats feed restricted at 0, 15, 30, and 45%, respectively. Histopathology of the dead and moribund rats indicated that the clinical signs were not characteristic of PBB toxicity. In a second experiment, safflower oil at 3.5% or excess vitamins prevented the mortality and clinical signs associated with MO during withdrawal from 100 ppm PBBs. Based on these data and those in the literature, PBBs interfere with vitamin utilization.

An ecotoxicological study of a population of the white footed mouse (Peromyscus leucopus) inhabiting a polychlorinated biphenyls-contaminated area.

White footed mice (Peromyscus leucopus) inhabiting an area surrounding a pond (Tyler) contaminated with polychlorinated biphenyls (PCBs) and metals (Cadmium, Zinc, Copper) had whole body burdens of 0.42-4.17 ppm PCBs (mean 2.3 ppm) and animals from a comparison nonpolluted site (WCC) had no detectable PCBs. Males and females caught at the polluted site in the winter months were not significantly different in body weight or length when compared to WCC animals, but Tyler animals had significantly increased relative liver, kidney, spleen and adrenal weights. In the summer months, mostly males were caught at both Tyler and WCC sites. Tyler males were significantly lighter than WCC males, and had a significantly increased relative liver weight when compared to the males from the WCC site. In addition, the adult Tyler males had significantly lower relative testis weights. At Tyler there was a significantly smaller proportion of juveniles and subadults in the population than at WCC. Polychlorinated biphenyls levels in the adult Tyler males were significantly positively correlated with relative liver weight, but there were no significant correlations with any of the other structures measured. These results suggest that at the polluted site there is inhibition of reproduction and changes in liver, spleen, adrenal, and testis function.

Enhanced withdrawal of polychlorinated biphenyls: a comparison of colestipol, mineral oil, propylene glycol, and petroleum jelly with or without restricted feeding.

Meat type chickens were fed a commercial mixture of polychlorinated biphenyl (PCB), Aroclor 1254, at 10 ppm for 14 days, then treated for 21 days to hasten the withdrawal of PCB with either mineral oil (MO), petroleum jelly (PJ), propylene glycol (PG), or colestipol (CO) at 5% of the diet, or at 10% of the diet when restricted to 50% of control intake (50% FR). Whole carcass analyses for PCB revealed that MO + 50% FR reduced PCB to 1.91 mg/bird, or 32% of the body burden (5.96 mg) in nontreated chickens previously fed PCB, whereas those restricted in feed intake by 50% (50% FR) had almost no change (6.44 mg/bird) in body burdens. The PJ, PG, and CO in combination with 50% FR reduced body burdens of PCB to 47, 57, and 77%, respectively, of the control value. When treated with MO, PJ, PG, or CO alone (no 50% FR), chickens had body burdens reduced to only 67 to 90% of control, depending on th compound. Thus, feed restriction was necessary for the MO and PJ to have their greatest effect. Carcass lipid values and body weight gains were markedly reduced by the feed restriction. The CO reduced carcass lipid in nonrestricted chickens by 30%.

Enhanced withdrawal from chickens of hexachlorobenzene (HCB) and pentachlorophenol (PCP) by colestipol, mineral oil, and/or restricted feeding.

Young chickens fed hexachlorobenzene (HCB) or pentachlorophenol (PCP) for 14 d at 10 ppm in the diet contained body burdens of 573 or 362 micrograms, respectively. These diets were withdrawn (d 0) and replaced for 21 d with diets containing 5% mineral oil (MO), or 5% colestipol (CO), a bile-acid-binding resin, or the chickens were restricted in feed intake to 50% of controls (50-RF), fed MO plus 50-RF, or CO plus 50-RF. Without any treatment during withdrawal, body burdens were reduced to 63% and 70% of the d 0 values for HCB and PCP, respectively. MO, CO, or 50-RF reduced body burdens of HCB to 37% of d 0 burdens, but the combination treatments with 50-RF reduced body burdens to 19% of d 0 values. PCP was at 35% of the d 0 burdens from 50-RF, while all other treatments had reduced body burdens to nondetectable amounts of less than 0.7 micrograms/bird by d 21 of withdrawal. Body fat was not reduced by mineral oil, but was reduced to some extent by CO, and was markedly reduced by 50-RF. 50-RF always reduced body burdens of PCP or HCB alone or in combination with MO or CO. These data are discussed in relationship to the nonbiliary excretion of xenobiotics.

Procedures to enhance withdrawal of xenobiotics from chickens.

Egg- and meat-type chickens were fed diets containing 1 or 10 ppm of fireMaster (FF-1), a commercial mixture of polybrominated biphenyls (PBBs), predominantly 2,4,5,2',4',5'-hexabromobiphenyl (6BB-4) and 2,3,4,5,2',4',5'-heptabromobiphenyl (7BB-8). These congeners account for approximately 65 and 14%, respectively, of the total mix. In three experiments, colestipol hydrochloride, a bile acid-binding resin, and mineral oil, alone or in combination with restricted feeding, were examined as procedures to enhance the removal of the PBBs. The combination of 50% dietary restriction plus a 10% dietary concentration of colestipol or mineral oil reduced body burdens of PBBs about 70% within 21 d for chickens previously fed 10 ppm PBBs. The use of feed restriction, colestipol, or mineral oil produced only borderline effects for hastening withdrawal. Chickens not treated showed only a 3% loss of PBBs during the withdrawal period. Colestipol at 2.5% in the diet in combination with feed restriction was not consistently effective in removing body burdens of PBB from chickens previously fed 1 or 10 ppm PBBs, indicating a dose-response effect. Chickens previously fed 1 ppm eliminated up to 40% of the PBBs in 21 d without any treatment, as compared to the 3% loss occurring after feeding with 10-ppm concentrations.

Effect of bile acids and diet composition on lipid absorption in chickens with cannulated bile ducts.

The effect of bile acids on lipid research was examined in meat-type chicks, 8 weeks of age, with cannulated cystic and hepatic ducts. The procedure allowed for biliary collection in free-roving birds. Shams retained 90 to 92% dietary fat and those with cannulated ducts retained 43 to 72%. Addition of .04, .08, or .16% cholic acid or .08% freeze-dried chicken bile did not improve lipid retention significantly. The percentage retained for tallow and corn oil was 57 and 64%, respectively, far less then the 75 and 90% values, respectively, obtained in normal chickens. Neither practical-type nor purified-type diets, saturated (tallow) nor unsaturated (corn oil) fats at 8% of the diet significantly influenced lipid retention in chickens with cannulated ducts. In these chickens, percent dry matter retained of the purified diet was 81%, a significantly higher value than the 62% retained of the practical-type diet.

Passage rate of feed in very young chicks.

White Leghorn chicks were reared on diets in which soybean oil at 4% or corn oil at 5 or 10% was substituted isocalorically for carbohydrate calories. The transit time ( TRT ) of diets was determined in these chicks with ferric oxide as a marker. The average TRT for three experiments was 167 min. Overall, there was no significant effect (P greater than .05) for the addition of the vegetable oils to alter TRT . A significant interaction was detected for TRT to be shorter as chicks aged from 7 to 21 days of age when provided with 4 to 5% vegetable oil but not when provided with 10% corn oil. An extra metabolic effect was detected from the isocaloric substitution of lipid calories for carbohydrate calories but not necessarily only when TRT was longer. Thus, the chick was affected differently than the hen in which lipid produced longer TRT .

Colestipol and energy restriction as an approach to hasten removal of PBBs from chickens.

Male White Leghorn chickens were fed either 0.1 or 1.0 ppm fireMaster FF-1 (FF-1) for 21 d. During the withdrawal phase, the chickens were fed 0, 0.5, or 2.5% colestipol hydrochloride, and anion exchange resin. Also, calories were restricted to 80% of control intake within certain groups during the first 14 d in each of 2 consecutive 21-d withdrawal periods. In the caloric-restricted groups, colestipol was fed at 0, 0.625, or 3.125% to yield equal daily intake of colestipol to those fed 0, 0.5, or 2.5% concentrations. During the first 21 d of withdrawal, colestipol at 2.5-3.125%, but not 0.5-0.625%, hastened excretion of polybrominated biphenyls (PBBs) by 50%. During d 22-42 of withdrawal, a background level of PBBs contamination was detected, which tended to confound the results. Despite this, higher levels of colestipol lowered overall body burdens of PBBs by 80% in comparison to the overall level of residues in the other groups of chickens, and by 20% in comparison to their own levels 21 d earlier. Dietary colestipol resulted in chickens with lower carcass lipid content. The combination of energy restriction plus colestipol at 2.5-3.125%, which had the greatest impact in reducing body weight gain and carcass lipid, seemed to be the most favorable treatments for hastening excretion of PBB residues.

Microsomal enzyme induction, egg production, and reproduction in three lines of Japanese quail fed polybrominated biphenyls.

The sensitivity of three genetic lines of Japanese quail to polybrominated biphenyls (PBBs) was evaluated using criteria of egg production, reproduction, and induction of the hepatic microsomal mixed-function oxidase (MFO) system. Two genetic lines of quail, developed to diverge in their plasma cholesterol response to exogenous adrenocorticotropin (ACTH) (a "Low" line and a "High" line), were compared to a random-bred line ("Random"). ACTH administration caused increases in plasma cholesterol in the Low line that were 15 and 39% below the Random-line values in males and females, respectively, while High-line values were 31% higher in males and 36% higher in females when compared to the respective Random-line values. Hepatic activities of aryl hydrocarbon hydroxylase (AHH) and hexobarbital hydroxylase (HxH) were not significantly influenced by ACTH administration or by genetic line in either sex. PBBs fed at 40 or 80 mg/kg diet for 5 wk resulted in significant increases in hepatic AHH and aminopyrine N-demethylase (APND) activities and cytochrome P-450 concentrations. The induction of AHH, APND, and cytochrome P-450 was significantly less in Low-line males in comparison to Random- and High-line males, while the induction of AHH was less in Low-line females when compared to females from the other two lines, based on covariance analysis. In terms of reproductive parameters, there was a greater adverse effect on egg production at 80 ppm PBBs in Low-line females when compared to the Random and High lines. These data indicate an example in which the biological toxicity of a compound and the induction of a 3-methylcholanthrene-type hepatic enzyme are not directly correlated.

Urinary cyclic AMP excretion in birds: dependence on parathyroid hormone activity.

The cyclic AMP response of avian kidney to parathyroid activity has been evaluated both in vitro and in vivo. The production of cyclic AMP by dispersed avian kidney cells was stimulated by bovine parathyroid hormone or by an extract of avian parathyroid glands. Intravenous infusion of bovine parathyroid hormone resulted in increased urinary excretion and plasma concentration of cyclic AMP, as well as increased plasma calcium and urinary phosphorus excretion. The increases in plasma and urinary cyclic AMP preceded those of plasma calcium and of phosphorus excretion. EDTA infusion resulted in a decrease in plasma calcium and an increase in urinary cyclic AMP excretion. After 10 days on a low-calcium diet, chickens exhibited a 4.5-fold increase in urinary cyclic AMP excretion. The results suggest that urinary cyclic AMP in chickens reflects PTH activity similar to some mammalian species.

Lipid alleviates fatty liver hemorrhagic syndrome.

At 135% of control, Single Comb White Leghorn laying hens were force fed for 3 weeks, diets based on corn or wheat, the latter made isocaloric to the corn-based diet with either corn oil, corn starch, or wheat starch. The hens fed ad libitum received a corn-based diet. Force feeding the corn-based diet produced fatty liver hemorrhagic syndrome (FLHS) with scores averaging 3.3 where 1 = no hemorrhages and 5 = 25 or more hemorrhagic points per liver. Force feeding the wheat-based diet with corn starch, wheat starch, or corn oil resulted in scores of 3.1, 2.7, and 1.9, respectively. Only the latter score was significantly different from the score produced by force feeding the corn-based diet, which when fed ad libitum resulted in an average score of 1.3. Based on these data and the criteria of retained energy, weight gain, percent fat in liver, and plasma estradiol concentrations, we concluded that wheat-based diets with corn- or wheat-starch produce FLHS equivalent to that caused by diets based on corn. Lipid at 4% of the diet had an alleviating effect on FLHS.

Lipid: the unidentified factor for alleviating fatty liver syndrome.

Laying hens were fed diets based on either corn-soybean meal (CS) or wheat-soybean meal (WS). The WS diets were formulated to be isocaloric to the CS diet by supplementing with either corn oil, corn starch, or wheat starch. Hens fed the WS diets with either of the starches had significantly (P less than or equal to .01) higher percentages of hepatic lipid than those fed WS diets with corn oil. Values for hepatic lipid of hens fed the CS diets were intermediate to those of the wheat-based diets. The supplementation of fish meal or a selenium salt to supply .4 mg Se per kilogram of diet did not prevent or alleviate the problem of fatty livers caused by feeding diets composed mostly of wheat-soy and starch. The data revealed that wheat does not have an unidentified factor preventing FLS. The indication is that lipid at proper amounts in the diet acts through feed-back mechanisms to prevent excessive hepatic lipid accumulation that starches enhance.