Attainment of peak bone mass and bone turnover rate in relation to estrous cycle, pregnancy and lactation in colony-bred Sprague-Dawley rats: suitability for studies on pathophysiology of bone and therapeutic measures for its management

Alteration in biochemical markers of bone turnover and bone mineral density (BMD) of whole body and isolated femur and tibia in relation to age, estrous cycle, pregnancy and lactation and suitability of use of rat as model for studies on pathophysiology of bone and therapeutic measures for its management were investigated. Immature rats (1, 1.5 and 2 month of age; weighing, respectively, 39.3 ± 1.0, 67.8 ± 2.4 and 87.2 ± 5.2 g) exhibited high rate of bone turnover, as evidenced by high serum osteocalcin and alkaline phosphatase and urine calcium/creatinine ratio. However, their BMD (whole body or of isolated long bones) was below measurable levels. Marked increase in body weight at 3 months (185.5 ± 5.2 g) was associated with low serum osteocalcin and alkaline phosphatase and urine calcium/creatinine ratio. Biochemical markers and BMD attained at puberty at 3 months were maintained until 36 month of age. No significant change in serum calcium was observed with increasing age or on any of the biomarkers during estrous cycle, and BMD of femur and tibia isolated during proestrus and diestrus stages was almost similar. Onset of pregnancy was associated with significant increase in serum total alkaline phosphatase and osteocalcin levels, but serum calcium, urine calcium/creatinine ratio or BMD of whole body or isolated long bones were not significantly different from that at proestrus stage. No marked change, except increase in body weight (P < 0.05), was also evident in these parameters between days 5 and 19 of pregnancy, irrespective of number of implantations in the uterus. A significant decrease in BMD of isolated femur (neck and mid-shaft regions) was observed on days 5 and 21 of lactation as compared to that during pregnancy or diestrus/proestrus stages of estrous cycle; the decrease being almost similar in females lactating two or six young ones. BMD of isolated tibia (global and region proximal to tibio-fibular separation point), though generally lower than that during cycle and pregnancy, was statistically non-significant. However, clear evidence of occurrence of osteoporosis during lactation, with decrease in BMD of >2.5 × S.D. in isolated femur (global, neck and mid-shaft) as well as tibia (global) was observed only when BMD data was analysed on T-/Z-score basis. Serum biochemical markers of bone turnover, too, were significantly increased in comparison to cyclic rats. Findings demonstrate marked increase in body weight and bone turnover during first 3 months of age, direct correlation between peak bone mass and onset of puberty at 3 months of age and increase in bone resorption rate during lactation. Finding of the study while might suggests possible use of rat as useful model for studies on bone turnover rate during lactation and post-weaning periods and extrapolation of the result to the human situation, but not in relation to ageing.     

Redescription of Besnoitia tarandi (Protozoa: Apicomplexa) from the reindeer (Rangifer tarandus)

Besnoitia tarandi tissue cysts were found in naturally-infected reindeer (Rangifer tarandus) from Finland. Infectivity of its tissue cysts, bradyzoites, and tachyzoites to animals and cell culture was studied. The bradyzoites and tissue cysts were not infectious to out-bred mice, rabbits or gerbils. When fed tissue cysts, neither cats nor dogs excreted oocysts. However, the parasite was lethal to interferon-gamma gene knock out mice irrespective of the route of inoculation. The parasite was grown successfully in African Green Monkey cells from tissues of two reindeer for the first time. Non-dividing, uninucleate tachyzoites from smears from cell cultures were 5.6 x 1.4 microm (4.5-7.4 x 1.0-1.9, n=50) in size. Longitudinally-cut bradyzoites in tissue sections measured 7.4 x 1.3 microm (6.5-7.8 x 1.0-1.6, n=30). Ultrastructurally, tachyzoites and bradyzoites were similar to those in other Besnoitia species, and in particular to parasites described from cattle (Besnoitia besnoiti) and equids (Besnoitia bennetti) in that their bradyzoites lacked enigmatic bodies. Based on comparative analysis of three portions of nuclear ribosomal DNA (the small and large subunits and the first internal transcribed spacer) B. tarandi was found to be more closely related to the other congeners described from ungulates. The parasite was formally redescribed and specimens deposited in the US National Parasite Collection.     

Molecular and biological characterization of Hammondia heydorni-like oocysts from a dog fed hearts from naturally infected white-tailed deer (Odocoileus Virginianus)

Neospora caninum and Hammondia heydorni are morphologically and phylogenetically related coccidians that are found in dogs. Although there is serological evidence of N. caninum infection in the white-tailed deer (Odocoileus virginianus), the parasite has not been yet isolated from the tissues of this host. In an attempt to isolate N. caninum from deer, hearts from 4 deer with antibodies to N. caninum were fed to 2 dogs. One of these dogs shed unsporulated oocysts 12-14 microm in diameter. Sporulated oocysts were not infective to Mongolian gerbils (Meriones ungulatus), and DNA isolated from these oocysts was not amplified using N. caninum-specific primers. However, positive amplification with the H. heydorni-specific first internal transcribed spacer (ITS-1) primers and common toxoplasmatiid ITS-1 primers confirmed the presence of H. heydorni DNA in the samples. The oocysts were considered to be H. heydorni on the basis of their morphology, biology, and molecular characteristics. This is the first record of a H. heydorni-like parasite in the white-tailed deer.     

Biologic and molecular characteristics of Toxoplasma gondii isolates from striped skunk (Mephitis mephitis), Canada goose (Branta canadensis), black-winged lory (Eos cyanogenia), and cats (Felis catus)

Toxoplasma gondii isolates can be grouped into 3 genetic lineages. Type I isolates are considered virulent to outbred mice, whereas Type II and III isolates are not. In the present report, viable T. gondii was isolated for the first time from striped skunk (Mephitis mephitis), Canada goose (Branta canadensis), and black-winged lory (Eos cyanogenia). For the isolation of T. gondii, tissues were bioassayed in mice, and genotyping was based on the SAG2 locus. Toxoplasma gondii was isolated from 3 of 6 skunks, 1 of 4 Canada geese, and 2 of 2 feral cats (Felis catus) from Mississippi. All donor animals were asymptomatic. Viable T. gondii was also isolated from 5 of 5 lories that had died of acute toxoplasmosis in an aviary in South Carolina. Genotypes of T. gondii isolates were Type III (all skunks, lories, and the goose) and Type II (both cats). All 5 Type III isolates from birds and 2 of the 3 isolates from skunks were mouse virulent.     

First isolation of Neospora caninum from an aborted bovine fetus in Spain

Neospora caninum was isolated from the brain of a 6-mo-old aborted bovine fetus from Galicia, Spain. The fetal brain homogenate was inoculated intraperitoneally into cortisonized mice. The peritoneal exudate from the infected mice, along with mouse sarcoma cells (Tg180), was inoculated into a second group of mice, and parasites were harvested from the peritoneal exudate. The parasites were adapted to in vitro growth in Vero monolayers. The tachyzoites from the peritoneal exudate reacted positively with anti-N. caninum antibodies and not with anti-Toxoplasma gondii antibodies on indirect fluorescent antibody test. The tachyzoites were lethal to interferon gamma gene knock out (KO) mice and could be identified immunohistochemically in the tissues. The identity of the parasite was also confirmed by polymerase chain reaction amplification of N. caninum-specific fragments. The sequences of the amplified gene 5 fragments (GenBank AY494944) were found to be identical to that of an Austrian isolate of N. caninum but not to that of NC-1. This is the first isolation of viable N. caninum from Spain.     

Seroepidemiology of infection with Toxoplasma gondii in workers occupationally exposed to water, sewage, and soil in Durango, Mexico

Water, sewage, and soil are potential sources of infection for Toxoplasma gondii. Therefore, we sought to determine the prevalence of T. gondii infection and associated characteristics in 61 plumbers, 203 construction workers, and 168 gardeners in Durango City, Mexico. Participants were tested for T. gondii IgG and IgM antibodies with the use of enzyme-linked immunoassays. In addition, sociodemographic, clinical, and behavioral characteristics from each participant were obtained. IgG T. gondii antibodies were found in 4 (6.6%) plumbers, 17 (8.4%) construction workers, and 10 (6.0%) gardeners; T. gondii IgM antibodies were found in 3 (1.5%) construction workers and 4 (2.4%) gardeners, but in none of the plumbers. In the total population, the prevalence of T. gondii infection was significantly higher in workers living in suburban areas, without education, workers that consumed chorizo, and those who suffered from any disease (P < 0.05). In gardeners, prevalence of infection was significantly higher in those with blood transfusion, and memory impairment (P < 0.05). Multivariate analysis showed that T. gondii infection was positively associated with consumption of unwashed fruits (adjusted odds ratio [OR] = 2.41; 95% confidence interval [CI]: 1.13-5.13), and with raising animals (adjusted OR = 2.53; 95% CI: 1.00-6.37). This is the first report of contributing factors for T. gondii infection in workers occupationally exposed to water, sewage, and soil in a Mexican city, and results will contribute to the design of optimal preventive measures.     

Serological and parasitological prevalence of Toxoplasma gondii in wild birds from Colorado

Ground-feeding birds are considered important in the epidemiology of Toxoplasma gondii because they serve as indicators of soil contamination by oocysts, and birds of prey are indicators of T. gondii prevalence in rodents and other small mammals. Cats excrete environmentally resistant oocysts after consuming tissues of T. gondii -infected birds. In the present study, sera and tissues from 382 wild birds from Colorado were tested for T. gondii infection. Antibodies to T. gondii were found in 38 birds with the use of the modified agglutination test (MAT, 1∶25 titer). Tissues (brains, hearts) of 84 birds were bioassayed in mice. Viable T. gondii was isolated from 1 of 1 barn owl (Tyto alba), 1 of 5 American kestrels (Falco sparverius), 1 of 7 ferruginous hawks (Buteo regalis), 1 of 4 rough-legged hawks (Buteo lagopus), 2 of 13 Swainson's hawks (Buteo swainsoni), and 1 of 25 red-tailed hawks (Buteo jamaicensis). This is the first time T. gondii has been isolated from the barn owl, ferruginous hawk, rough-legged hawk, and Swainson's hawk.     

Binuclear manganese(III) complexes of an unsymmetric pyrazolate-based compartmental ligand with hard donor set

The synthesis, crystal structure and magnetic properties of manganese(III) binuclear complexes [Mn^III₂(L-3Н)₂(CH₃ОH)₄]·2CH₃ОH (1) and [Mn^III₂(L-3Н)₂(Py)₄]·2Py (2) (L = 3-[(1E)-N-hydroxyethanimidoyl]-4-methyl-1H-pyrazole-5-carboxylic acid) are reported. The ligand contains two distinct donor compartments formed by the pyrazolate-N and the oxime or the carboxylic groups. The complexes were characterized by X-ray single crystal diffraction, revealing that both 1 and 2 consist of dinuclear units in which the two metal ions are linked by double pyrazolate bridges with a planar {Mn₂N₄} core. Cryomagnetic measurements show antiferromagnetic interaction with g = 1.99, J = −3.6 cm⁻¹, Θ = −2.02 K for 1 and g = 2.00, J = −3.7 cm⁻¹, Θ = 1.43 K for 2.     

Waterborne toxoplasmosis - Recent developments

Humans become infected with Toxoplasma gondii mainly by ingesting uncooked meat containing viable tissue cysts or by ingesting food or water contaminated with oocysts from the feces of infected cats. Circumstantial evidence suggests that oocyst-induced infections in humans are clinically more severe than tissue cyst-acquired infections. Until recently, waterborne transmission of T. gondii was considered uncommon, but a large human outbreak linked to contamination of a municipal water reservoir in Canada by wild felids and the widespread infection of marine mammals in the USA provided reasons to question this view. The present paper examines the possible importance of T. gondii transmission by water.     

Dynein mediates retrograde neurofilament transport within axons and anterograde delivery of NFs from perikarya into axons: regulation by multiple phosphorylation events

We examined the respective roles of dynein and kinesin in axonal transport of neurofilaments (NFs). Differentiated NB2a/d1 cells were transfected with green fluorescent protein-NF-M (GFP-M) and dynein function was inhibited by co-transfection with a construct expressing myc-tagged dynamitin, or by intracellular delivery of purified dynamitin and two antibodies against dynein's cargo domain. Monitoring of the bulk distribution of GFP signal within axonal neurites, recovery of GFP signal within photobleached regions, and real-time monitoring of individual NFs/punctate structures each revealed that pertubation of dynein function inhibited retrograde transport and accelerated anterograde, confirming that dynein mediated retrograde axonal transport, while intracellular delivery of two anti-kinesin antibodies selectively inhibited NF anterograde transport. In addition, dynamitin overexpression inhibited the initial translocation of newly-expressed NFs out of perikarya and into neurites, indicating that dynein participated in the initial anterograde delivery of NFs into neurites. Delivery of NFs to the axon hillock inner plasma membrane surface, and their subsequent translocation into neurites, was also prevented by vinblastine-mediated inhibition of microtubule assembly. These data collectively suggest that some NFs enter axons as cargo of microtubues that are themselves undergoing transport into axons via dynein-mediated interactions with the actin cortex and/or larger microtubules. C-terminal NF phosphorylation regulates motor association, since anti-dynein selectively coprecipitated extensively phosphorylated NFs, while anti-kinesin selectively coprecipitated less phosphorylated NFs. In addition, however, the MAP kinase inhibitor PD98059 also inhibited transport of a constitutively-phosphorylated NF construct, indicating that one or more additional, non-NF phosphorylation events also regulated NF association with dynein or kinesin.