The structure of ScC2 (X̃2A1): A combined Fourier transform microwave/millimeter-wave spectroscopic and computational study.

Pure rotational spectra of Sc13C2 (X̃2A1) and Sc12C13C (X̃2A') have been measured using Fourier transform microwave/millimeter-wave methods. These molecules were synthesized in a DC discharge from the reaction of scandium vapor, produced via laser ablation, with 13CH4 or 13CH4/12CH4, diluted in argon. The NKa,Kc = 10,1 → 00,0, 20,2 → 10,1, 30,3 → 20,2, and 40,4 → 30,3 transitions in the frequency range of 14 GHz-61 GHz were observed for both species, each exhibiting hyperfine splittings due to the nuclear spins of 13C (I = 1/2) and/or Sc (I = 7/2). These data have been analyzed with an asymmetric top Hamiltonian, and rotational, spin-rotation, and hyperfine parameters have been determined for Sc13C2 and Sc12C13C. In addition, a quartic force field was calculated for ScC2 and its isotopologues using a highly accurate coupled cluster-based composite method, incorporating complete basis set extrapolation, scalar relativistic corrections, outer core and inner core electron correlation, and higher-order valence correlation effects. The agreement between experimental and computed rotational constants, including the effective constant (B + C), is ∼0.5% for all three isotopologues. This remarkable agreement suggests promise in predicting rotational spectra of new transition metal-carbon bearing molecules. In combination with previous work on Sc12C2, an accurate structure for ScC2 has been established using combined experimental (B, C) and theoretical (A) rotational constants. The radical is cyclic (or T-shaped) with r(Sc-C) = 2.048(2) Å, r(C-C) = 1.272(2) Å, and ∠(C-Sc-C) = 36.2(1)°. The experimental and theoretical results also suggest that ScC2 contains a C2 - moiety and is largely ionic.

Meeting report: Emerging respiratory viral infections and nonhuman primate case reports.

A workshop on Emerging Respiratory Viral Infections and Spontaneous Diseases in nonhuman primates was sponsored by the concurrent Annual Meetings of the American College of Veterinary Pathologists and the American Society for Veterinary Clinical Pathology, held December 1-5, 2012, in Seattle, Washington. The session had platform presentations from Drs Karen Terio, Thijs Kuiken, Guy Boivin, and Robert Palermo that focused on naturally occurring influenza, human respiratory syncytial virus, and metapneumovirus in wild and zoo-housed great apes; the molecular biology and pathology of these viral respiratory diseases in nonhuman primate (NHP) models; and the therapeutic and vaccine approaches to prevention and control of these emerging respiratory viral infections. These formal presentations were followed by presentations of 14 unique case studies of rare or newly observed spontaneous lesions in NHPs (see online files for access to digital whole-slide images corresponding to each case report at http://scanscope.com/ACVP%20Slide%20Seminars/2012/Primate%20Pathology/view.apml). The session was attended by meeting participants that included students, pathology trainees, and experienced pathologists from academia and industry with an interest in respiratory and spontaneous diseases of NHPs.

Testing paradigm for prediction of development-limiting barriers and human drug toxicity.

The financial investment grows exponentially as a new chemical entity advances through each stage of discovery and development. The opportunity exists for the modern toxicologist to significantly impact expenditures by the early prediction of potential toxicity/side effect barriers to development by aggressive evaluation of development-limiting liabilities early in drug discovery. Improved efficiency in pharmaceutical research and development lies both in leveraging "best in class" technology and integration with pharmacologic activities during hit-to-lead and early lead optimization stages. To meet this challenge, a discovery assay by stage (DABS) paradigm should be adopted. The DABS clearly delineates to discovery project teams the timing and type of assay required for advancement of compounds to each subsequent level of discovery and development. An integrative core pathology function unifying Drug Safety Evaluation, Molecular Technologies and Clinical Research groups that effectively spans all phases of drug discovery and development is encouraged to drive the DABS. The ultimate goal of such improved efficiency being the accurate prediction of toxicity and side effects that would occur in development before commitment of the large prerequisite resource. Good justification of this approach is that every reduction of development attrition by 10% results in an estimated increase in net present value by $100 million.

Acute fulminant sarcocystosis in a captive-born rhesus macaque.

A captive-born juvenile female rhesus macaque (Macaca mulatta) was acquired from a commercial breeder and placed in quarantine. Within 8 days of arrival, the animal became anorexic, inactive, and dehydrated. Subsequently, generalized edema and facial ecchymoses developed, and despite supportive therapy, the animal became moribund and was euthanatized. Macroscopic examination showed diffuse stippling and streaking of the myocardium. Histopathologic examination revealed multifocal to coalescing myocardial edema, necrosis, lymphohistiocytic inflammation, and generalized endothelial infection with Sarcocystis sp. Immature and mature schizonts within endothelial cells were most prevalent in the heart. Fewer schizonts were present in the vasculature of other tissues, including skeletal muscle, smooth muscle, adipose tissue, brain, and retina. Mature tissue cysts within muscle fibers were not found in the myocardium but were occasionally seen in skeletal muscle. Analysis of polymerase-chain-reaction-amplified 18s ribosomal RNA gene sequences revealed 96% identity to published sequences of S. hirsuta, S. hominis, and S. fusiformis and 95% identity to S. cruzi and S. tenella. However, sequences did not show complete identity with any organism in the GenBank database. Sequence homology suggests that this is a newly described Sarcocystis sp. Results of antibody tests for simian retrovirus, simian T-lymphotropic virus 1, and simian immunodeficiency virus were negative, suggesting that viral immunosuppression was unlikely to have augmented the pathogenicity of sarcosporidial infection. Clinical and histopathologic findings in this case of fulminant sarcosporidiosis are similar to those described in Dalmeny disease in cattle, which is associated with ingestion of massive numbers of infective Sarcocystis oocysts.

Dimethylheptyl-THC-11 oic acid: a nonpsychoactive antiinflammatory agent with a cannabinoid template structure.

OBJECTIVE: To assess the antiinflammatory activity of dimethylheptyl-THC-11 oic acid (DMH-11C), a nonpsychoactive synthetic derivative of tetrahydrocannabinol. METHODS: Acute inflammation was induced by injection of interleukin-1beta and tumor necrosis factor alpha into subcutaneous air pouches formed on the backs of mice. Inflammation was quantified 6 hours later by pouch fluid leukocyte counts. Adjuvant-induced polyarthritis in rats was used as a model of chronic inflammation and joint tissue injury. Animals were either untreated, treated with safflower oil, or treated with DMH-11C in safflower oil. Arthritis was assessed by clinical observation and by histomorphologic evaluation of tibiotarsal joints. RESULTS: Oral administration of DMH-11C reduced the accumulation of pouch fluid leukocytes and significantly reduced the severity of adjuvant-induced polyarthritis. Histopathologic studies of tibiotarsal joints showed that DMH-11C treatment attenuated pannus formation and joint tissue injury. CONCLUSION: DMH-11C suppresses acute inflammation in the subcutaneous air pouch in mice and chronic joint inflammation characteristic of adjuvant disease in rats. These results demonstrate the potential use of this nonpsychoactive cannabinoid as an antiinflammatory agent.

Neuroinvasion by simian immunodeficiency virus coincides with increased numbers of perivascular macrophages/microglia and intrathecal immune activation.

During peak viremia and initial antibody response, rhesus macaques infected with pathogenic and nonpathogenic isolates of SIV show distinct differences in viral load and tissue distribution. Animals infected with pathogenic isolates of SIV invariably have virus in the CSF and brain parenchyma by two weeks postinoculation, whereas animals infected with nonpathogenic isolates do not. Mechanisms underlying neuroinvasion by SIV and HIV are unknown, but recruitment of latently infected mononuclear cells from the peripheral circulation (Trojan horse theory) is frequently proposed. Circulating monocytes, from which perivascular macrophage/microglia are derived, are a likely vehicle for cell-associated transport of virus across the blood-brain barrier. This transport and the kinetics of perivascular macrophage/microglial turnover in the CNS likely depend on endothelial and leukocyte adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), which has previously been shown to be upregulated on cerebrovascular endothelium in SIV encephalitis. To investigate the role of peripheral monocyte recruitment into the perivascular macrophage/microglial cell pool at the time of initial viral neuroinvasion, we examined the temporal relationships among perivascular macrophage/microglia density, endothelial VCAM-1 expression and localization of viral nucleic acid in the CNS of macaques acutely infected with pathogenic and nonpathogenic molecular clones of SIV. The concentration of CSF quinolinic acid, a marker of intrathecal immune and macrophage activation, was examined concurrently. We found that significant increases in the density of perivascular macrophages/microglia coincided with viral neuroinvasion and marked elevations in CSF quinolinic acid. Furthermore, combined in situ hybridization and immunohistochemistry demonstrated that infected perivascular cells were macrophages/microglia. These findings provide evidence suggesting that neuroinvasion occurs through an influx of infected monocytes which take up residence in the CNS as perivascular macrophages/microglia. VCAM-1 expression, however, was not clearly correlated with these events, thus its contribution to initial viral neuroinvasion is unclear.

Localization of simian immunodeficiency virus nucleic acid and antigen in brains of fetal macaques inoculated in utero.

Neurological dysfunction has been shown to be associated with human immunodeficiency virus (HIV) infection. The incidence of these abnormalities is greater in HIV-infected children when compared with adults, and the patterns of neurological disease are also known to differ from those observed in the adult population. The reasons for these differences are unclear but are most likely related to the immaturity of the host's immune and central nervous systems at the time of infection. This is thought to be particularly true for infants infected with HIV prenatally. To examine these questions, the brains of fetal rhesus macaques that were infected with SIVmac251 at various time points in utero were examined. Direct fetal inoculations were performed on gestational day (GD) 65 (n = 8; early second trimester), GD 110 (n = 4; early third trimester) and GD 130 (n = 2; mid third trimester), with harvest of fetal tissues on GD 80, 100, 130, or 145. Eleven sham controls were included with harvest at correlative time points. Specimens were examined by routine histology, immunohistochemistry, and in situ hybridization to localize viral antigens and SIV nucleic acid. Histologically, scattered glial nodules, spongiosis, and mineralization were found in the basal ganglia and deep white matter in 4 of the 14 fetuses (3 inoculated on GD 65 and one on GD 110). These fetuses and those without histological lesions had viral nucleic acid and SIV antigen in the stroma of the choroid plexus, meninges, and external granular layer of the cerebellum and in columns of cells in the cortical plate. In contrast to juvenile and adult macaques, very few SIV-positive perivascular mononuclear cells were present. These findings suggest that SIV has a different distribution in the brain of fetal macaques after direct infection when compared with adult or juvenile animals. Furthermore, the results of these studies suggest that differences in neurological disease between pediatric and adult patients with acquired immune deficiency syndrome are most likely related to the time of infection.

VCAM-1 expression and leukocyte trafficking to the CNS occur early in infection with pathogenic isolates of SIV.

This study reports on the endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) in the central nervous system (CNS) early after experimental infection of rhesus monkeys (Macaca mulatta) with pathogenic and nonpathogenic simian immunodeficiency virus (SIV). Diffuse endothelial expression of VCAM-1 was observed in the CNS in all animals receiving pathogenic SIV. These findings demonstrate the rapidity with which pathogenic SIV is able to enter the CNS and induce endothelial cell activation.