Trichinella spiralis: Comparison with an Arctic isolate

The muscle phase of Trichinella spiralis and of Trichinella sp. isolated in the Arctic was compared in experimental and wild animals. Reproductive capacity indices (RCI) of the Trichinella sp. isolate were significantly lower in laboratory rodents but were similar to T. spiralis in wild rodents. Sprague-Dawley rats were the most refractory to the Trichinella sp. isolate of all laboratory rodents. Outbred strains of mice were more susceptible to both T. spiralis and the Trichinella sp. isolate than inbred strains of mice. T. spiralis muscle larvae survived longer in mice and the survival of both T. spiralis and the Trichinella sp. isolate larvae was higher in female mice. While single pair interbreeding experiments showed reproductive isolation between T. spiralis and the Trichinella sp. isolate, multiple pair and transplant breeding experiments showed reproductive compatibility. Male and female infective larvae of T. spiralis and the Trichinella sp. isolate differed morphometrically, but a convergence in size of worms was observed after prolonged passages of the parasites in mice. Passaging history of the isolate and host species was found to have a significant effect on Trichinella morphology. It is proposed that the Trichinella sp. isolate is a physiological variant of T. spiralis and not a distinct species.     

Structural and functional homology between the 29 kD rat liver nucleoprotein and the high mobility group 1 protein

A 29 kD soluble rat liver nucleoprotein (p29) has increased binding affinity for the hormone responsive element (RE) of the rat haptoglobin (Hp) gene during the acute-phase reaction. In this work the possibility of its structural and functional homology to the high mobility group 1 (HMG1) nonhistone protein constituent of chromatin was examined. The results of two-dimensional gel electrophoresis, Southwestern and Western immunoblot analyses, showed that p29 and HMG1 are homologous protein species. On the basis of in vitro and in vivo phosphorylation/dephosphorylation experiments, we discuss the modulatory role of phosphate groups in view of the structure and function of p29.     

Dose response of Cryptosporidium parvum in outbred neonatal CD-1 mice.

Cryptosporidium parvum infectivity in a neonatal CD-1 mouse model was used to determine the dose needed to infect 50% of the population. The 50% infective dose was estimated to be 79 oocysts. It was observed that a mean oral inoculum of 23 oocysts produced infection in 2 of 25 neonatal mice 7 days postinoculation. All animals became infected when the mean oral dose exceeded 310 oocysts per animal. The dose response of C. parvum was modeled with a logit dose-response model suitable for use in water disinfection studies.     

Ozone inactivation of Cryptosporidium parvum in demand-free phosphate buffer determined by in vitro excystation and animal infectivity.

Inactivation of Cryptosporidium parvum oocysts by ozone was performed in ozone demand-free 0.05 M phosphate buffer (pH 6.9) in bench-scale batch reactors at 7 and 22 degrees C. Ozone was added to each trial from a concentrated stock solution for contact times ranging from 5 to 15 min. The viability of the control and treated oocysts was determined by using in vitro excystation and infection in neonatal CD-1 mice. It was found that excystation consistently underestimated inactivation when compared with animal infectivity (P < or = 0.05). As inactivations increased, the difference between excystation and infectivity also increased. The inactivation kinetics of C. parvum by ozone deviated from the simple first-order Chick-Watson model and was better described by a nonlinear Hom model. The use of the Hom model for predicting inactivation resulted in a family of unique concentration and time values for each inactivation level rather than the simple CT product of the Chick-Watson model.     

Protoveratrines A and B increase sleep apnea index in Sprague-Dawley rats

Trbovic, Sinisa M., Miodrag Radulovacki, and David W. Carley. Protoveratrines A and B increase sleep apneaindex in Sprague-Dawley rats. J. Appl.Physiol. 83(5): 1602-1606, 1997.The action ofprotovertarines A and B, which stimulate carotid sinus baroreceptorsand vagal sensory endings in the heart as well as pulmonary bed, wereassessed on spontaneous and postsigh central sleep apneas in freelymoving Sprague-Dawley rats. During the 6-h recording period, animalswere simultaneously monitored for sleep by using electroencephalogramand electromyogram recordings, for respiration by single-chamberplethysmography, and for blood pressure and heart period by usingradiotelemetry. After administration of 0.2, 0.5, or 1 mg/kg sc ofprotoveratrines, cardiopulmonary changes lasting at least 6 h wereobserved in all three behavioral states [heart period increasedup to 23% in wakefulness, 21% in non-rapid-eye-movement (non-REM)sleep, and 20% in REM sleep; P < 0.005 for each]. At the same time, there was a substantial increase in the number of spontaneous (375% increase;P = 0.04) and postsigh (268%increase, P = 0.0002) apneas. Minuteventilation decreased by up to 24% in wakefulness, 25% in non-REM,and 35% in REM sleep (P < 0.05 foreach). We conclude that pharmacological stimulation of baroreflexespromotes apnea expression in the sleeping rat.

     

Trichinella spiralis: comparison of stages in host intestine with those of an Arctic Trichinella sp

The intestinal phase of Trichinella spiralis and of Trichinella sp. isolated in the Arctic were compared in experimental animals. Reproductive capacity, pathogenicity, distribution, and persistence of adults in the small intestine, morphological measurements, and release of newborn larvae in vitro were examined. Numerous passages of 40 days each for T. spiralis and the Trichinella sp. isolate in mice did not affect reproductive capacity, distribution of adults in the small intestine, and size of worms. Reproductive capacity index for T. spiralis, I = 151.27 ± 27.30 was significantly higher compared to the Trichinella sp. isolate index, I = 63.46 ± 19.34. The Trichinella sp. isolate was more pathogenic to mice and wild rodents compared to T. spiralis during the intestinal phase. Both parasites were located in the anterior part of the small intestine but the position of T. spiralis adults (P = 17.08) differed from position of the Trichinella sp. isolate adults (P = 23.46) in the small intestine. Intestinal phase of T. spiralis was longer (20 days) compared to the Trichinella sp. isolate (15 days) but sex ratios (:♂) were similar for both parasites. T. spiralis females released significantly higher numbers of larvae in vitro/24 hr compared to the Trichinella sp. isolate. Release of larvae was continuous during the intestinal phase and the average fecundity for T. spiralis was 335 larvae/female and for the Trichinella sp. isolate 114 larvae/female. Adults of T. spiralis and the Trichinella sp. isolate were morphologically indistinguishable and did not differ in size. A comparative index for the intestinal phase is proposed for comparison of any Trichinella spp. isolates and standard T. spiralis.     

Trade‐offs between land and water requirements for large‐scale bioenergy production

Bioenergy is expected to play an important role in the future energy mix as it can substitute fossil fuels and contribute to climate change mitigation. However, large‐scale bioenergy cultivation may put substantial pressure on land and water resources. While irrigated bioenergy production can reduce the pressure on land due to higher yields, associated irrigation water requirements may lead to degradation of freshwater ecosystems and to conflicts with other potential users. In this article, we investigate the trade‐offs between land and water requirements of large‐scale bioenergy production. To this end, we adopt an exogenous demand trajectory for bioenergy from dedicated energy crops, targeted at limiting greenhouse gas emissions in the energy sector to 1100 Gt carbon dioxide equivalent until 2095. We then use the spatially explicit global land‐ and water‐use allocation model MAgPIE to project the implications of this bioenergy target for global land and water resources. We find that producing 300 EJ yr^?1 of bioenergy in 2095 from dedicated bioenergy crops is likely to double agricultural water withdrawals if no explicit water protection policies are implemented. Since current human water withdrawals are dominated by agriculture and already lead to ecosystem degradation and biodiversity loss, such a doubling will pose a severe threat to freshwater ecosystems. If irrigated bioenergy production is prohibited to prevent negative impacts of bioenergy cultivation on water resources, bioenergy land requirements for meeting a 300 EJ yr^?1 bioenergy target increase substantially (+ 41%) – mainly at the expense of pasture areas and tropical forests. Thus, avoiding negative environmental impacts of large‐scale bioenergy production will require policies that balance associated water and land requirements.     

Influence of cytology development on frequency of pre-cancerous lesions and cervical cancer in east Croatia, 1978-2001

We analyzed the influence of cytology development to frequency of precancerosa (Cervical intraepithelial neoplasia grade 3 - CIN 3) and cervical cancer. The number of examined Pap smears increased significantly in the analyzed period. The calculated linear trend shows an average four-year increase of 17,283.35 smears. The number of detected CIN 3 increased accordingly. The calculated linear trend shows an average four-year increase by 45.03 and decrease of the rate of 0.07. A slight increase in cervical cancer was also noticed. The calculated linear trend shows an average four-year increase in cancer by 1.6 and decrease in the rate of 0.51. Analyses of cervical cancer by stages showed an increase in number of stage I and decrease of other stages. The calculated linear trend shows an average four-year increase of stage I by 4.94 or decrease in other stages of cervical cancer of 3.29 respectively. The rate of cervical cancer stage I decreased by 0.11 and of other stages by 0.39. Further analyses of the stage I showed that the linear trend of IA stage had an average four-year increase by 5.40 and decrease in stage IB of 0.48. The rate of the cervical cancer stage IA increased by 0.02, whereas the rate of IB decreased by 0.13. Cytology development in our country has resulted in detection of higher number of CIN 3 and the earliest stage (IA) of cervical cancer whereas the number of other stages (IB, II, III, IV) has decreased. However, a total number of cervical cancers haven't changed over the whole period. Thus, it is obvious that opportunistic program of detection, which has been using in Croatia, could not decrease frequency of cervical cancer. In order to achieve it, well-organized national program of detection is needed.