Zero field splitting of the chalcogen diatomics using relativistic correlated wave-function methods.

The spectrum arising from the (π*)(2) configuration of the chalcogen dimers, namely, the X(2)1, a2, and b0(+) states, is calculated using wave-function theory based methods. Two-component (2c) and four-component (4c) multireference configuration interaction (MRCI) and Fock-space coupled cluster (FSCC) methods are used as well as two-step methods spin-orbit complete active space perturbation theory at 2nd order (SO-CASPT2) and spin-orbit difference dedicated configuration interaction (SO-DDCI). The energy of the X(2)1 state corresponds to the zero-field splitting of the ground state spin triplet. It is described with high accuracy by the 2- and 4-component methods in comparison with experiment, whereas the two-step methods give about 80% of the experimental values. The b0(+) state is well described by 4c-MRCI, SO-CASPT2, and SO-DDCI, but FSCC fails to describe this state and an intermediate Hamiltonian FSCC ansatz is required. The results are readily rationalized by a two-parameter model; Δε, the π* spinor splitting by spin-orbit coupling and K, the exchange integral between the π(1)* and the π(-1)* spinors with, respectively, angular momenta 1 and -1. This model holds for all systems under study with the exception of Po(2).

Investigation of a mumps outbreak among university students with two measles-mumps-rubella (MMR) vaccinations, Virginia, September-December 2006.

Following the clinical diagnosis of the first case of mumps on September 22, 2006 at the University of Virginia (UVA), 52 suspected cases were identified through active surveillance for mumps by the end of December 2006. Samples were collected from 47 students who presented with parotitis despite a documented history of two doses of measles, mumps, and rubella (MMR) vaccine. Six of 47 serum samples (13%) were positive for mumps IgM, and 46/47 specimens were positive for mumps IgG. Endpoint titration of acute phase serum samples from laboratory-confirmed cases did not provide evidence that elevated serum IgG is a consistent marker for infection among cases due to secondary vaccine failure. Buccal swab samples from 39 of the 47 students were tested by real-time reverse transcription-polymerase chain reaction (RT-PCR) and/or viral culture. Mumps virus or mumps RNA was detected in 12 of 39 buccal samples (31%). Genetic analysis of the virus from the outbreak at UVA indicated that the outbreak was not linked to the large mumps outbreak in the Midwestern US that occurred earlier in 2006. Our findings support the use of viral detection to improve laboratory diagnosis of mumps among persons who have received two doses of MMR.

Bonding analysis using localized relativistic orbitals: water, the ultrarelativistic case and the heavy homologues H2X (X = Te, Po, eka-Po).

We report the implementation of Pipek-Mezey [J. Chem. Phys. 90, 4916 (1989)] localization of molecular orbitals in the framework of a four-component relativistic molecular electronic structure theory. We have used an exponential parametrization of orbital rotations which allows the use of unconstrained optimization techniques. We demonstrate the strong basis set dependence of the Pipek-Mezey localization criterion and how it can be eliminated. We have employed localization in conjunction with projection analysis to study the bonding in the water molecule and its heavy homologues. We demonstrate that in localized orbitals the repulsion between hydrogens in the water molecule is dominated by electrostatic rather than exchange interactions and that freezing the oxygen 2s orbital blocks polarization of this orbital rather than hybridization. We also point out that the bond angle of the water molecule cannot be rationalized from the potential energy alone due to the force term of the molecular virial theorem that comes into play at nonequilibrium geometries and which turns out to be crucial in order to correctly reproduce the minimum of the total energy surface. In order to rapidly assess the possible relativistic effects we have carried out the geometry optimizations of the water molecule at various reduced speed of light with and without spin-orbit interaction. At intermediate speeds, the bond angle is reduced to around 90 degrees , as is known experimentally for H(2)S and heavier homologues, although our model of ultrarelativistic water by construction does not allow any contribution from d orbitals to bonding. At low speeds of light the water molecule becomes linear which is in apparent agreement with the valence shell electron pair repulsion (VSEPR) model since the oxygen 2s12 and 2p12 orbitals both become chemically inert. However, we show that linearity is brought about by the relativistic stabilization of the (n + 1)s orbital, the same mechanism that leads to an electron affinity for eka-radon. Actual calculations on the series H2X (X = Te, Po, eka-Po) show the spin-orbit effects for the heavier species that can be rationalized by the interplay between SO-induced bond lengthening and charge transfer. Finally, we demonstrate that although both the VSEPR and the more recent ligand close packing model are presented as orbital-free models, they are sensitive to orbital input. For the series H2X (X = O, S, Se, Te) the ligand radius of the hydrogen can be obtained from the covalent radius of the central atom by the simple relation r(lig)(H) = 0.67r(cov)(X) + 27 (in picometers).

Serum antibody responses to equine herpesvirus 1 glycoprotein D in horses, pregnant mares and young foals.

The envelope glycoprotein D of equine herpesvirus 1 (EHV-1 gD) has been shown in laboratory animal models to elicit protective immune responses against EHV-1 challenge, and hence is a potential vaccine antigen. Here we report that intramuscular inoculation of EHV-1 gD produced by a recombinant baculovirus and formulated with the adjuvant Iscomatrix elicited virus-neutralizing antibody and gD-specific ELISA antibody in the serum of over 90% of adult mixed breed horses. The virus-neutralizing antibody responses to EHV-1 gD were similar to those observed after inoculation with a commercially available killed EHV-1/4 whole virus vaccine. Intramuscular inoculation of EHV-1 gD DNA encoded in a mammalian expression vector was less effective in inducing antibody responses when administered as the sole immunogen, but inoculation with EHV-1 gD DNA followed by recombinant EHV-1 gD induced increased gD ELISA and virus-neutralizing antibody titres in six out of seven horses. However, these titres were not higher than those induced by either EHV-1 gD or the whole virus vaccine. Isotype analysis revealed elevated gD-specific equine IgGa and IgGb relative to IgGc, IgG(T) and IgA in horses inoculated with EHV-1 gD or with the whole virus vaccine. Following inoculation of pregnant mares with EHV-1 gD, their foals had significantly higher levels of colostrally derived anti-gD antibody than foals out of uninoculated mares. The EHV-1 gD preparation did not induce a significant mean antibody response in neonatal foals following inoculation at 12 h post-partum and at 30 days of age, irrespective of the antibody status of the mare. The ability of EHV-1 gD to evoke comparable neutralizing antibody responses in horses to those of a whole virus vaccine confirms EHV-1 gD as a promising candidate for inclusion in subunit vaccines against EHV-1.

Meningitis bacteriana aguda con hipertensión endocraneal / Acute bacterial meningitis with intracranial hypertension

A pesar del uso de la dexametasona, la mortalidad de la meningitis bacteriana aguda (MBA) continúa siendo elevada en los casos que precisan ingreso en UCI. Este hecho podría relacionarse, entre otros factores, con la presencia de hipertensión endocraneal (HTEC), que en la mayoría de ocasiones no es tratada de modo intensivo. El estudio de Doppler transcraneal con codificación de color (DTCC), una técnica no invasora que nos permite monitorizar la hemodinámica cerebral, seleccionaría a un grupo de pacientes con alta sospecha de HTEC, permitiendo un tratamiento más agresivo de estos pacientes, que incluiría el tratamiento neurocrítico como en el traumatismo craneoencefálico. Presentamos un caso clínico de una meningitis bacteriana aguda tratada según los resultados obtenidos en el DTCC. La paciente recibió tratamiento con manitol y coma barbitúrico, con un resultado favorable. (AU)

Significado del patrón electrocardiográfico de ingreso en el infarto agudo de miocardio tratado con trombólisis / Meaning of initial electrocardiographic pattern in acute myocardial infartion treated with thrombolysis

Fundamento. Estudiar el grado de asociación entre el patrón electrocardiográfico de ingreso en el infarto agudo de miocardio, la falta de eficacia de la trombólisis y el mayor riesgo de disfunción ventricular izquierda. Pacientes y métodos. Se estudiaron retrospectivamente 150 pacientes ingresados de manera consecutiva por infarto de menos de 6 h de evolución, que recibieron tratamiento trombolítico. Los pacientes se agruparon según el patrón electrocardiográfico, definido por la presencia o ausencia de distorsión de la porción terminal del complejo QRS. Se consideraron criterios de reperfusión el pico temprano de CK/CKMB, el descenso del segmento ST mayor del 50 per cent y la negativización de la onda T a las 2 h postrombólisis. Se realizó un análisis estadístico mediante el test de la t de Student para variables cuantitativas y el de la 2 para las cualitativas. Resultados. La edad media de los pacientes, 131 varones y 19 mujeres, fue de 60 años. Un total de 80 infartos fueron de cara inferior y 59 de pared anterior. No existieron diferencias entre los grupos en cuanto a sexo, tipo y tiempo de inicio de la trombólisis, criterios de reperfusión, resultados de la ergometría y la coronariografía, episodios de angina postinfarto o arritmias malignas y fallecimientos. Los pacientes con distorsión final del complejo QRS presentaron infartos de mayor tamaño (CK/CKMB = 3.207[1662]/403 [226] U frente a 2.251[1564]//281[186] U, p = 0,001). Los pacientes con distorsión del complejo QRS presentaron mayor presencia de claves Killip III/IV (OR = 5,44; IC del 95 per cent, 1,01-229,13; p = 0,002) y disfunción ventricular izquierda severa (OR = 3,2; IC del 95 per cent 1,06-9,66; p = 0,003). Conclusión. El patrón electrocardiográfico del ingreso en el infarto agudo de miocardio tratado con trombólisis no se asocia con la respuesta al tratamiento trombolítico, pero sí con el tamaño del infarto y la disfunción ventricular izquierda. (AU)

Sustained ventricular tachycardia as a marker of inadequate myocardial perfusion during the acute phase of myocardial infarction.

BACKGROUND: Sustained ventricular tachycardia (VT) complicating the acute phase of myocardial infarction (AMI) is a quite rare event but with short-term unfavorable prognosis. The clinical characteristics as well as the therapeutic implications have not yet been well defined. HYPOTHESIS: This paper attempts to prove that VT may be considered a marker of inadequate myocardial perfusion after thrombolysis. METHODS: To assess the clinic-electroangiographic characteristics and prognosis of patients with VT occurring within the first 4 days of an AMI, a case-control study was carried out in 23 patients from a total of 1,100 patients (1.9%) hospitalized with AMI between March 1993 and July 1997. These patients were compared with a control group of 131 patients hospitalized consecutively. A statistical analysis was made using the chi-square test, t-test, and logistic regression. RESULTS: There were no differences among groups with regard to age, gender, and area of necrosis. Average time for the onset of VT was 26 h (range 0-92 h). Sixteen patients underwent coronary angiography: 4 patients had left main coronary artery disease, 2 had single-vessel disease, 8 had lesions in two vessels, and 2 had triple-vessel disease. Univariate analysis showed that patients with VT had a higher incidence of creatine phosphokinase (CPK)-MB peak > 300 UI/l (61 vs. 30%; p<0.001), more frequent occurrence of previous AMI (48 vs. 17%; p<0.001), and acute intraventricular conduction disorders (26 vs. 4%; p<0.001). Furthermore, these patients suffered ischemia previous to VT more frequently (65 vs. 11%; p<0.0001), and had a greater mortality rate than that in the control group (35 vs. 4%; p<0.0001). In the multivariant analysis, the variables related to the occurrence of VT were CPK-MB peak > 300 IU/l (OR 5.9; 95% CI 1.6-21), acute intraventricular conduction disorders (OR 9.02; 95% CI 1.7-48), and ischemia immediately prior to VT (odds ratio [OR] 19.64; 95% confidence interval [CI] 5.3-73). CONCLUSIONS: Ventricular tachycardia may be considered a marker of inadequate myocardial perfusion after thrombolysis; therefore, a more aggressive revascularization treatment in these patients would be advisable. The profile of patients with AMI, hospitalized in the coronary care unit, who will likely suffer from VT is previous AMI, CPK-MB peak > 300, acute intraventricular conduction disorders, Killip > I, and ischemia previous to VT.

Processes for obtaining nonmedical exemptions to state immunization laws.

OBJECTIVES: This study sought to determine the specific processes required for obtaining religious and philosophical exemptions to school immunization laws. METHODS: State health department immunization program managers in the 48 states that offer nonmedical exemptions were surveyed. Categories were assigned to reflect the complexity of the procedure within a state for obtaining an exemption. RESULTS: Sixteen of the states delegated sole authority for processing exemptions to school officials. Nine states had written policies informing parents who seek an exemption of the risks of not immunizing. The complexity of the exemption process, in terms of paperwork or effort required, was inversely associated with the proportion of exemptions field. CONCLUSIONS: In many states, the process of claiming a nonmedical exemption requires less effort than fulfilling immunization requirements.

Implicación pronóstica de la sospecha clínica inicial en la disección de aorta torácica. Revisión de los métodos diagnósticos utilizados / Prognostic significance of the initial diagnostic suspicion in cases of thoracic aortic dissection. review of the diagnostic techniques

Objetivo. Analizar la importancia de la sospecha clínica inicial en el diagnóstico de la disección de aorta torácica y la influencia en su pronóstico, revisar los diferentes métodos complementarios utilizados. Material y métodos. Se estudiaron retrospectivamente 33 casos de disección de aorta torácica entre enero de 1993 y junio de 1998, valorándose parámetros clínico-epidemiológicos, diagnósticos de ingreso y pruebas complementarias. Los resultados cualitativos se valoraron mediante 2.Resultados. La sintomatología típica de disección (dolor torácico, abdominal e interescapular) se apreció en 19 (58 por ciento) casos. La sospecha clínica al ingreso se realizó en 9 (27 por ciento) de los pacientes, siendo diagnósticos tardíos/casuales 22 (67 por ciento ) casos. Se realizó el diagnóstico de disección a través de la necropsia en 2 (6 por ciento) ocasiones. Diagnósticos erróneos de ingreso fueron: cardiopatía isquémica en 9 casos; isquemia de miembros inferiores en 3. Se realizó el diagnóstico de cólico hepático, neumonía, gastroenteritis, síncope, cólico nefrítico, aneurisma de aorta abdominal, pancreatitis y dolor osteomuscular respectivamente en un caso. El retraso en el diagnóstico no influyó significativamente en la mortalidad. La prueba diagnóstica que se utiliza en nuestro medio en primer lugar es la tomografía axial computarizada (TAC). La aortografía se utiliza como prueba confirmatoria del diagnóstico. Conclusiones. No se valoran adecuadamente los datos de la clínica inicial. La mortalidad es mayor en el grupo de pacientes en el cual no hay sospecha clínica inicial de disección de aorta (AU)

New genetic group of measles virus isolated in the People's Republic of China.

Genetic and antigenic characterization of 14 wild-type measles viruses isolated from four provinces in the People's Republic of China during 1993 and 1994 was conducted. Sequence analyses of the hemagglutinin (H) and nucleoprotein (N) genes indicated that 13 of the 14 Chinese viruses comprised a previously undescribed genetic group. Viruses from this unique group were the most genetically diverse measles viruses described, so far. The Chinese viruses differed from other wild-type viruses by as much as 6.9% in the H gene and 7.0% in the N gene at the nucleotide level. One of the 14 viruses was a member of the same genetic group that contains the Edmonston strain. Antigenic analysis using monoclonal antibodies to the H protein did not detect significant differences in binding patterns between the Chinese viruses and other wild-type measles viruses. In addition, representative viruses from the unique Chinese group were neutralized by both human post-vaccination antiserum and mouse antiserum against the H protein of the Edmonston vaccine virus. Viruses closely related to these Chinese viruses were also associated with importations of measles into the United States during 1997 from Vietnam and Hong Kong suggesting that viruses from this new genetic group continue to circulate in China and possibly other parts of Asia.

Measles outbreaks in Micronesia, 1991 to 1994.

BACKGROUND: Several islands in Micronesia experienced large measles outbreaks, during 1991 through 1994. Except for Guam, none of the islands had reported measles outbreaks during the previous 20 years. METHODS: To characterize the outbreaks, measles surveillance data, hospital records and death certificates were reviewed. Preoutbreak vaccination coverage rates were assessed by reviewing public health vaccination records. Viral isolates were genetically sequenced to determine the source of transmission. Linear regression analysis was performed to assess the effectiveness of outbreak control measures. RESULTS: Between 1991 and 1994 more than 1300 measles cases and 16 measles-related deaths were reported in Micronesia. Preoutbreak vaccination coverage rates among 2-year-old children were 55 to 94%. Genetic sequencing of the viral isolates and epidemiologic investigations suggested transmission between islands and new importations from outside of Micronesia. The highest attack rates were among children ages < 5 years (20/1000) and 10 to 19 years (38/1000). Compared with attack rates among children ages < 1 and 10 to 19 years, attack rates were lower among those ages 5 to 9 years, in whom 2-dose vaccination coverage rates were highest (P < 0.001). Early and rapid implementation of mass vaccination campaigns was significantly associated with shorter duration of outbreaks (P = 0.049). CONCLUSION: The measles outbreaks in Micronesia show that island populations may be highly susceptible to measles. High two-dose vaccination coverage levels must be maintained to prevent such outbreaks. Early and rapidly implemented mass measles vaccination campaigns were effective in control of island outbreaks. Strengthening public health infrastructure and surveillance is necessary for early identification of outbreaks and rapid implementation of mass campaigns.

Genetic analysis of measles viruses isolated in the United States, 1995-1996.

Genetic analysis was conducted on 28 wild type measles viruses isolated from outbreaks or cases in the United States during 1995-1996. These viruses were members of at least 6 distinct genetic groups. However, none of these viruses was related to the group 2 viruses that were associated with the resurgence of measles in the United States between 1989 and 1992 except for a single importation from the Philippines. The sequence data support and extend previous findings showing that transmission of group 2 viruses within the United States was interrupted after 1993. The data also suggest that all measles cases that occurred in the United States in 1995-1996 were the result of importation of virus, even in instances when the source was unknown. Molecular epidemiologic studies can provide a means to measure the success of measles control programs by helping to identify the transmission pathways of the virus.

Molecular epidemiology of measles virus: identification of pathways of transmission and implications for measles elimination.

The nucleotide sequences of either the hemagglutinin or nucleoprotein genes from wild type measles viruses isolated in the United States between 1989 and 1992 differed by < 0.5%. This suggests that the majority of viruses associated with resurgence of measles in the United States belonged to a single indigenous genotype. In contrast, wild type viruses isolated from sporadic outbreaks of measles in the United States during 1994 were genetically heterogeneous. These viruses were more closely related to wild type viruses previously circulating in Europe, Africa, or Japan and were epidemiologically linked to importations or no known source. In addition to demonstrating the utility of genetic analysis in understanding the epidemiology of measles, these data suggest that the transmission of the indigenous virus was interrupted after the 1989-1992 epidemic. Measures to further reduce the incidence of measles in the United States should include efforts to control importation and subsequent spread of measles.

Virology of measles virus.

Measles virus is the prototypic member of the Morbillivirus genus of the family Paramyxoviridae. The viral genomic RNA is single-stranded, nonsegmented, and of negative polarity and encodes six major structural proteins. The two viral transmembrane glycoproteins, the hemagglutinin and fusion proteins, are both required for virus-host cell membrane fusion, while attachment to host cells is mediated by the hemagglutinin. The human CD46 molecule has been identified as a cellular receptor for measles virus. Antibodies raised against either viral glycoprotein neutralize measles virus in vitro and protect against infection. Although measles virus remains a single serotype (monotypic), nucleotide sequence analyses have identified distinct lineages among recent wild type isolates. These genetic changes were manifested by detectable antigenic variation between vaccine and wild type viruses and at some point may influence strategies for control, elimination, and eventual eradication of measles virus.

Comparison of sequences of the H, F, and N coding genes of measles virus vaccine strains.

Many live-attenuated vaccines for measles virus have been developed using either the prototype Edmonston strain or other locally isolated measles strains. The attenuation methods used to develop these vaccines have differed in the type(s) of cell line(s) used, number of passages, and temperatures of incubation. To assess the extent of genetic diversity within vaccine strains and to determine the extent to which the varied passage histories may have affected the viruses, we conducted sequence analyses of the fusion, hemagglutinin, nucleoprotein, and matrix genes of Edmonston-derived and non-Edmonston-derived strains. Despite the diverse geographic origins of the vaccine viruses and the different attenuation methods used, there was remarkable sequence similarity among all strains examined. The sequences of all of the vaccine strains were very similar to the sequences of a low-passage seed of the original Edmonston strain. The most divergent sequences were from two of the non-Edmonston-derived vaccines: CAM-70, a vaccine developed from a Japanese wild-type virus, and S-191, which was developed in China.

Genetic variability of the glycoprotein genes of current wild-type measles isolates.

The glycoprotein coding sequences from three wild-type measles viruses isolated in the United States during 1988-1989 were examined by mRNA templated sequencing to determine whether contemporary strains have undergone genetic changes relative to the vaccine strain, Moraten. These studies revealed variation in the hemagglutinin (HA) gene and, to a far lesser degree, the fusion (F) gene. The F protein coding region was highly conserved with only three predicted amino acid changes. Among the predicted amino acid changes identified in the HA was a new potential glycosylation site at residue 416, located toward the carboxy-terminal end of the HA peptide. Eighty percent of the predicted amino acid changes in the HA shared by the three wild-type isolates were clustered near the five previously identified potential glycosylation sites. A linear pattern of evolutionary change was observed after comparing the predicted amino acid HA changes from the 1988-1989 viruses to those predicted in the HA protein from U.S. wild types isolated in 1977 and 1983.

Cocirculation of two distinct evolutionary lineages of influenza type B virus since 1983.

During 1988-1989 two highly distinct antigenic variants of influenza type B were recognized in hemagglutination-inhibition tests with postinfection ferret serum. These viruses were antigenically related to either B/Victoria/2/87, the most recent reference strain, or B/Yamagata/16/88, a variant that was isolated in Japan in May 1988. All influenza B viruses isolated in the United States during an epidemic in the winter of 1988-1989 were antigenically related to B/Victoria/2/87. However, in several countries in Asia, both B/Victoria/2/87-like viruses and B/Yamagata/16/88-like viruses were isolated. Sequence analysis of the hemagglutinin (HA) genes of several influenza B isolates from 1987 to 1988 indicated that the HA1 domains of the B/Yamagata/16/88-like viruses and B/VI/87-like viruses isolated in 1988 differed by 27 amino acids. Evolutionary relationships based on this sequence data indicated that the B/Yamagata/16/88-like viruses were more closely related to epidemic viruses from 1983 (B/USSR/100/83-like viruses) than to more recent reference strains such as B/Victoria/2/87. All other Asian strains, as well as selected isolates from the United States in 1988, were confirmed by sequence analysis as being genetically related to B/Victoria/2/87. These data provide clear evidence that two parallel evolutionary pathways of influenza type B have existed since at least 1983 and that viruses from each of the separate lineages were isolated from cases of influenza B in 1988. This finding is similar to earlier observations for type A H1N1 and H3N2 influenza viruses.

CT-scan in the diagnosis of patellar malalignment.

Fifty-one knees with patellofemoral symptoms, but with normal conventional radiographs, were studied by CT-scan. All but five showed evidence of malalignment, and when operated on had an abnormality of the articular cartilage. The authors conclude that in many cases a CT-scan is the best diagnostic procedure for the evaluation of disorders of the patellofemoral joint.