Strongyloides westeri worm and egg counts in naturally infected young horses.

Strongyloides westeri is a threadworm parasite found in the small intestine mainly in foals at up to about 4 months of age. This parasite is associated with small intestinal enteritis and diarrhea as well as skin irritation and a clinical syndrome called "frenzied behavior" due to percutaneous invasion. The aim of this study was to investigate S. westeri parasite burdens in age groups older than the initial lactogenic transmission phase. Secondary aims were to examine the impact of host age and gender on worm burden and egg output in naturally infected foals. Thirteen foals were enrolled in the study, exposed to natural infection with S. westeri and were humanely euthanized at ages ranging from 89 to 221days old. Egg counts per gram of feces were determined using the Mini-FLOTAC method. Worms were retrieved from the mucosa of the anterior half of the small intestine using a digestion method and enumerated. The foals were all observed to be healthy with no signs of parasitic disease. Foals at 4-5 months of age had significantly higher S. westeri worm and egg counts compared to those aged 6-8 months (p<0.05). Fecal egg counts were significantly associated with worm counts (p=0.0045). While egg and worm counts declined markedly in the 6-8 month age range, they were not eliminated completely. This could either reflect a new infection acquired orally or transcutaneously, or a subset of adult intestinal parasites acquired via the lactogenic route and surviving for longer time periods. This study provided new information about S. westeri infection patterns in young horses at 4-8 months of age.

The Mayak Worker Dosimetry System (MWDS 2013): Soluble Plutonium Retention in the Lungs of An Occupationally Exposed USTUR Case.

For the first time, plutonium retention in human upper airways was investigated based on the dosimetric structure of the human respiratory tract proposed by the International Commission on Radiological Protection (ICRP). This paper describes analytical work methodology, case selection criteria, and summarizes findings on soluble (ICRP 68 Type M material) plutonium distribution in the lungs of a former nuclear worker occupationally exposed to plutonium nitrate [239Pu(NO3)4]. Thirty-eight years post-intake, plutonium was found to be uniformly distributed between bronchial (BB), bronchiolar (bb) and alveolar-interstitial (AI) dosimetric compartments as well as between the left and right lungs. 239+240Pu and 238Pu total body activity was estimated to be 2333 ± 23 and 42.1 ± 0.7 Bq, respectively. The results of this work provide key information on the extent of plutonium binding in the upper airways of the human respiratory tract.

Low-dose almitrine bismesylate enhances hypoxic pulmonary vasoconstriction in closed-chest dogs.

The effect of almitrine bismesylate on the hypoxic pulmonary vasoconstrictor response was studied in six closed-chest dogs anesthetized with pentobarbital and paralyzed with pancuronium. The right lung was ventilated continuously with 100% O2; the left lung was ventilated either with 100% O2 ("hyperoxia") or with an hypoxic gas mixture ("hypoxia": end-tidal oxygen tension = 60.3 +/- 0.6 mm Hg). On two consecutive days, each dog received either almitrine (Vectarion, Servier Lab) or malic acid. Consecutive almitrine doses of 0.003, 0.03, 0.3, and 3.0 micrograms.kg-1.min-1, or the equivalent volumes of malic acid without almitrine, were administered intravenously as a constant peripheral infusion for 15 min. Percent blood flow to each lung was calculated based on a variation of the traditional shunt equation. The change in percent left lung blood flow (delta %QL-VA) increased significantly between the hypoxia-no drug and the hypoxia-almitrine (3.0 micrograms.kg-1.min-1) phase. No significant changes occurred during the other almitrine doses or the respective malic acid control phases. The change in arterial oxygen tension (delta PaO2) also increased significantly between the hypoxia-no drug and the hypoxia-almitrine (3.0 micrograms.kg-1.min-1) phase. No significant changes occurred during the other almitrine doses or the respective malic acid control phases. It is concluded that in dogs low-dose almitrine enhances hypoxic pulmonary vasoconstriction and that this enhancement is dose-related.

Results of a cleanup and treatment test at the Nevada test site: evaluation of vacuum removal of Pu-contaminated soil.

We have conducted experiments to evaluate the effectiveness of removing contaminated soils from the Nevada Test Site with a large truck-mounted vacuum cleaner. Our results show that this method is effective, relatively easy, and safe for equipment operators. With four passes of the truck-mounted vacuum, 92% of the 241Am (and the accompanying 239 + 240Pu) was removed and resuspension rates were reduced by more than 99%. The ecological impact was, however, serious in terms of soil erosion and destruction of small animal habitats. Compared to standard earth-moving techniques, vacuuming permits a significant reduction in the volume of soil collected to achieve the desired level of decontamination, and the volume reduction could result in cost savings for packaging, shipment, and burial. This cost savings would only be realized for projects involving decontamination of the top 5 cm of soil.

Mechanical factors do not influence blood flow distribution in atelectasis.

The contribution of mechanical factors to the vascular resistance of the atelectatic lung has been studied in vivo in the anesthetized open-chest dog. When the left lung was ventilated with an hypoxic gas mixture (while the right lung was ventilated with 100% O2), left lung blood flow decreased from 0.99 +/- 0.11 1.min-1 to 0.40 +/- 0.08 1.min-1 due to hypoxic pulmonary vasoconstriction (hypoxic stimulus PSO2 = 36.1 +/- 0.8 mmHg). When the left lung was made atelectatic, blood flow decreased to 0.65 +/- 0.11 1.min-1, consistent with a weaker hypoxic stimulus (PSO2 = 54.0 +/- 3.2 mmHg). With the addition of sodium nitroprusside infused intravenously, left lung blood flow increased to 1.05 +/- 0.14 1.min-1 during atelectasis, and to 0.61 +/- 0.09 1.min-1 during hypoxic ventilation, while flow remained at 0.94 +/- 0.18 1.min-1 during hyperoxic ventilation. When the results were plotted on pressure-flow diagrams, the hyperoxic, hypoxic, and atelectatic lung points fell on the same pressure-flow line in the presence of nitroprusside. It is concluded that hypoxic pulmonary vasoconstriction is the major (but not necessarily only) determinant of increased vascular resistance in the atelectatic lung, and that passive mechanical factors do not measurably affect blood flow distribution during open-chest atelectasis.

Intravenous PGF2 alpha infusion does not enhance hypoxic pulmonary vasoconstriction during canine one-lung hypoxia.

The effect of prostaglandin F2 alpha (PGF2 alpha) on the hypoxic pulmonary vasoconstrictor (HPV) response was studied in 12 closed-chest dogs anesthetized with pentobarbital and paralyzed with pancuronium. The right lung was ventilated continuously with 100% O2, while the left lung was either ventilated with 100% O2 ("hyperoxia") or ventilated with an hypoxic gas mixture ("hypoxia:" end-tidal PO2 approximately equal to 50.0 +/- 0.1 mmHg). Cardiac output (CO) was altered from a "normal" value of 2.89 +/- 0.26 1.min-1 to a "high" value of 3.55 +/- 0.26 1.min-1 by opening arteriovenous fistulae which allowed measurements of two points along a pressure-flow line. These four phases of left lung hypoxia or hyperoxia with normal and high cardiac output were performed in the absence of, and in the presence of, PGF2 alpha administered as a constant peripheral intravenous infusion of 1.0 microgram.kg-1.min-1. During left lung hypoxia, mean pulmonary artery pressure (PAP) increased significantly when compared to hyperoxia. With PGF2 alpha administration, mean PAP increased significantly during both hyperoxia and hypoxia. The presence or absence of PGF2 alpha had no effect on cardiac output or PaO2 during hypoxia. Relative blood flow to each lung was measured with a differential CO2 excretion (VCO2) method corrected for the Haldane effect. With both lungs hyperoxic, the percent left lung blood flow (%QL-VCO2) was 45 +/- 1%. When the left lung was exposed to hypoxia, the %QL-VCO2 decreased significantly to 29 +/- 3%. However, with the administration of PGF2 alpha, the %QL-VCO2 during left lung hypoxia did not change significantly 26 +/- 3%.(ABSTRACT TRUNCATED AT 250 WORDS)

High-dose almitrine bismesylate inhibits hypoxic pulmonary vasoconstriction in closed-chest dogs.

The effect of almitrine bismesylate on the hypoxic pulmonary vasoconstrictor (HPV) response was studied in seven closed-chest dogs anesthetized with pentobarbital and paralyzed with pancuronium. The right lung was ventilated continuously with 100% O2, while the left lung was ventilated with either 100% O2 ("hyperoxia") or with an hypoxic gas mixture ("hypoxia": end-tidal PO2 = 50.1 +/- 0.1 mmHg). Cardiac output (CO) was altered from a "normal" value of 3.10 +/- 0.18 l . min-1 to a "high" value of 3.92 +/- 0.16 l . min-1 by opening arteriovenous fistulae which allowed measurements of two points along a pressure-flow line. These four phases of left lung hypoxia or hyperoxia with normal and high cardiac output were repeated in the presence and absence of almitrine. Almitrine bismesylate was administered as a constant infusion of 14.3 micrograms . kg-1 . min-1 for a mean plasma concentration of 219.5 +/- 26.4 ng . ml-1. Relative blood flow to each lung was measured with a differential CO2 excretion (VCO2) method corrected for the Haldane effect. With both lungs hyperoxic, the percent left lung blood flow (%QL-VCO2) was 44 +/- 1%. When the left lung was exposed to hypoxia, the %QL-VCO2 decreased significantly to 22 +/- 1%. However, with the administration of almitrine, the %QL-VCO2 during left lung hypoxia increased significantly to 36 +/- 2%. The arterial oxygen tension decreased significantly between hyperoxia (PaO2 = 633 +/- 6 mmHg) and hypoxia (271 +/- 31 mmHg). With the addition of almitrine, there was no change during hyperoxia; however, during hypoxia, the PaO2 decreased significantly to 124 +/- 15 mmHg. Cardiac output did not influence these findings. The pulmonary vascular conductance (G) is the slope of the pressure-flow line.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypoxic pulmonary vasoconstriction is not potentiated by repeated intermittent hypoxia in closed chest dogs.

Hypoxic pulmonary vasoconstrictor (HPV) responses were measured with repeated intermittent hypoxic challenges in eight non-traumatized closed chest dogs anesthetized with pentobarbital. The right lung was ventilated continuously with 100% O2 while the left lung was either ventilated with 100% O2 (control) or ventilated with a gas mixture containing 3-4% O2 (hypoxia). Mean per cent left lung blood flow for all four normoxic periods was 43.1 +/- 1.5% (mean +/- SE) of the total blood flow by the SF6 excretion method and 40.8 +/- 1.1% by the differential CO2 excretion method, corrected for the Haldane effect. With hypoxic ventilation, flow diversion from the hypoxic lung was maximal with the first exposure and did not change subsequently with a total of four alternating exposures to normoxia and hypoxia. Flow diversion during hypoxia was approximately 50.5 +/- 2.4% by the SF6 method and 50.3 +/- 3.5% by the VCO2 method. This result contrasts with the increasing flow diversion response with intermittant hypoxic exposure that has been reported in animals exposed first to thoracotomy and surgical dissection. It is concluded that in the absence of surgical trauma the initial response to hypoxia is maximal and is not potentiated by repeated hypoxic stimulation.

Radiographic examination of mandibular lesions in barren-ground caribou.

Dental anomalies were observed in 43 of 1,226 barren-ground caribou (Rangifer tarandus groenlandicus) taken between 1966 and 1968. In five of these 43 animals, the mandibles had deformities which radiography showed to be the result of dental abscesses in four cases and probably of a trauma in the other. The absence of actinomycotic lesions of the jaw bones of these 1,226 animals, and of more than 500 examined previously, indicates that "lumpy jaw" is rare in barren-ground caribou. The authors suggest the use of radiography to determine the nature of bone growth on skeletal remains, in the absence of soft tissues for examination for Actinomyces, either microscopically or by cultural methods.

Chromosome breakage studies in lymphocytes from normal women, pregnant women, and women taking oral contraceptives.

Cytogenetic studies of 977 lymphocyte cultures from ten normal men and 54 normal women have shown: (1) variations in the frequencies of chromosome breakages among consecutive cultures from the same person and among cultures from different people, indicating that many extraneous factors may affect lymphocyte chromosomes, and (2) significantly higher average breakages in cultures from nulligravidas taking oral contraceptives (OC) and in pregnant women who had had previous pregnancies than in nulligravidas who had never taken the pill. The increase in breakages in cultures from the OC users was not observed in all cultures and could not be correlated with length of time on pill or stage of the pill cycle, suggesting that synthetic hormones do not directly damage lymphocyte chromosomes. Since estrogens and progestogens are known to affect many metabolic and biochemical systems, it is possible that these substances may induce in OC users and pregnant women a slightly altered in vivo condition in which increased chromosome breakages may be expressed.