Changes in acetabular orientation during total hip arthroplasty.

AIMS: The aims of this study were to determine the change in pelvic sagittal alignment before, during, and after total hip arthroplasty (THA) undertaken with the patient in the lateral decubitus position, and to determine the impact of these changes on acetabular component position. PATIENTS AND METHODS: We retrospectively compared the radiological pelvic ratio among 91 patients undergoing THA. In total, 41 patients (46%) were female. The mean age was 61.6 years (sd 10.7) and the mean body mass index (BMI) was 20.0 kg/m2 (sd 5.5). Anteroposterior radiographs were obtained: in the standing position preoperatively and at six weeks postoperatively; in the lateral decubitus position after trial reduction intraoperatively; and in the supine position in the post-anaesthesia care unit. Pelvic ratio was defined as the ratio between the vertical distance from the inferior aspect of the sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior aspect of the SI joints. Changes in the apparent component position based on changes in pelvic ratio were determined, with a change of > 5° considered clinically significant. Analyses were performed using Wilcoxon's signed-rank test, with p < 0.05 considered significant. RESULTS: Intraoperatively, in the lateral decubitus position, the pelvic ratio increased (anterior tilt) in 69.4% of cases, did not change significantly in 20.4%, and decreased (posterior tilt) in 10.2% of cases. When six-week postoperative radiographs were compared with preoperative radiographs, the pelvic ratio decreased in 44.9% of cases, did not change significantly in 42.3%, and increased in 12.8% of cases. This change in alignment correlated with a change in acetabular component version of > 5° in 79.6% of cases intraoperatively and 57.7% of cases at six weeks postoperatively. CONCLUSION: Changes in pelvic sagittal pelvic position occur throughout THA that, if unaccounted for, introduce errors in acetabular component placement. The use of intraoperative imaging may help the appropriate placement of the acetabular component. Cite this article: Bone Joint J 2019;101-B(6 Supple B):45-50.

Andes virus associated with hantavirus pulmonary syndrome in northern Argentina and determination of the precise site of infection.

Hantavirus pulmonary syndrome (HPS) has been documented in the Salta and Jujuy provinces of northern Argentina since 1991 and 1997, respectively, accounting for almost 50% of the cases of HPS reported in this country. Andes (AND) virus, specifically the AND virus Nort lineage, was previously associated with human disease in this region. Genetic analysis of viral medium RNA segments obtained from 18 HPS cases showed the existence of three AND virus Nort sublineages co-circulating in these two provinces. They showed a nucleotide sequence diversity of up to 11.1% between the sublineages. The putative site of infection of one of these cases (Sal3/97) was determined. A 100% nucleotide sequence identity was observed between the viral sequence found in patient Sal3/97 and in two virus-positive Oligoryzomys chacoensis captured in the same place where the case lived and worked. These results indicated the putative site of infection and identified this rodent species as the source of infection.

Complete nucleotide sequence of the M RNA segment of Andes virus and analysis of the variability of the termini of the virus S, M and L RNA segments.

Hantavirus pulmonary syndrome (HPS) has been recognized increasingly as a significant public health problem in South America since Andes virus was first discovered in Argentina. Here, the isolation of Andes virus is reported from an infected rodent captured in Argentina in close vicinity to the place of the first HPS case, AH1. The complete nucleotide sequences of the virus M segment, partial L segment and the termini of the S, M and L segment genome RNAs were determined. The Andes virus M RNA segment is 3671 nt in length and is predicted to encode a glycoprotein precursor 1138 aa in length; it generally resembles the other HPS-associated hantaviruses in its organization. Relative to the G1 glycoprotein of other HPS-associated hantaviruses, an additional potential glycosylation site was found but this is located in the predicted cytoplasmic domain and is therefore unlikely to be glycosylated. In phylogenetic analyses, Andes virus, together with the more related hantaviruses, represented a monophyletic lineage. The S-terminal nucleotides were conserved relative to other New World hantaviruses. The M and L segment RNA termini had short deletions in the region believed to contain the sequence and structural features necessary for initiation of virus RNA replication and transcription. Clinical manifestations of Andes virus infections range from fulminant respiratory disease with high lethality to mild course without sequelae. Andes virus has also been associated with person-to-person transmission. Accumulation of Andes virus genetic data will be essential for understanding the factors that regulate virus replication and transmission and to determine the pathogenesis of HPS.

Genetic diversity, distribution, and serological features of hantavirus infection in five countries in South America.

Since 1995 when the first case of hantavirus pulmonary syndrome (HPS) was reported in Patagonia, there have been more than 400 cases of HPS reported in five countries in South America. The first case of HPS was associated with Andes (AND) virus. In this study, we report on the genetic diversity, geographical distribution, and serological features of hantavirus infection in six countries in South America based on 87 HPS cases from Argentina, Bolivia, Chile, Paraguay, and Uruguay. An early immunoglobulin M (IgM), IgA, and IgG humoral response was observed in almost all HPS cases. The IgM response appears to peak 1 or 2 days after the onset of symptoms. Peak IgG antibody titers occur mostly after the first week. Low IgG titers or the absence of IgG was associated with higher mortality rates. The IgA response peaks around day 15 and then rapidly decreases. The results of phylogenetic analysis based on partial M-fragment G1- and G2-encoding sequences showed that HPS cases from the five countries were infected with viruses related to AND or Laguna Negra (LN) virus. Within AND virus-infected persons, at least five major genetic lineages were found; one lineage was detected in Uruguayan and Argentinean cases from both sides of the Rio de la Plata river. Two Paraguayan patients were infected with a virus different from LN virus. According to the results of phylogenetic analyses, this virus probably belongs to a distinct lineage related more closely to the AND virus than to the LN virus, suggesting that there is probably an Oligoryzomys-borne viral variant circulating in Paraguay. These studies may contribute to a better understanding of hantavirus human infection in South America.

Development and evaluation of a solid-phase enzyme immunoassay based on Andes hantavirus recombinant nucleoprotein.

Hantavirus pulmonary syndrome (HPS) with high mortality rate has been reported in five countries in South America. Rapid accurate methods are important both for monitoring acute infections and for epidemiological studies. The Andes virus nucleoprotein amino acid sequence has a high identity percentage compared with other sequences of this region and has been chosen for the development of diagnostic reagents. Andes nucleoprotein expressed in Escherichia coli was applied as antigen in IgG, IgA and mu-capture IgM enzyme-linked inmunosorbent assays (ELISAs). An evaluation of this reagent was conducted to establish its usefulness for differential diagnosis of HPS and seroprevalence studies. Samples from 135 reverse transcription (RT)-PCR-confirmed HPS cases, 77 individuals with other respiratory infections and 957 healthy inhabitants from endemic and non-endemic areas were analysed. The hantavirus-infected patients had an early and strong IgM, IgG and IgA serum antibody response, in most of the cases as early as 1, 7 and 1 days following onset of symptoms, respectively. IgM and IgG detection showed a specificity and sensitivity of 100%. Andes-specific IgM antibodies were found in all patients in the first available sample, which remained detectable for at least 43 days. Specific IgA antibodies were also detected in saliva of patients with acute HPS. The short duration of the disease and the risk for contacts due to person-to-person transmission of Andes virus necessitate the use of highly sensitive tests which might lead to earlier detection of infected people and improve the treatment and management of patients with HPS.

Hantavirus pulmonary syndrome outbreak in Argentina: molecular evidence for person-to-person transmission of Andes virus.

An increase of Hantavirus Pulmonary Syndrome (HPS) cases around a southwestern Argentina town and in persons living 1400 km away but in contact with those cases was detected during the spring of 1996. In order to evaluate person-to-person transmission we compared the homology of PCR-amplified viral sequences of 26 Argentine and Chilean cases. Sixteen of them were epidemiologically linked cases and had the same sequence (Epilink/96) in the S segment 3' noncoding region and in the M segment partial G1 and G2 region (a total of 1075 nucleotides). Contrarily, two geographical and contemporary but nonepidemiologically related cases differed from Epilink/96 in the compared regions. No significant differences, such as glycosylation or hydrophilic pattern, were found between Epilink/96 and the other sequences. Nucleotide and deduced amino acid sequence homologies between samples from southern Argentina and Chile ranged from 90.9 to 100% and 96.4 to 100%, respectively. Phylogenetic analysis revealed that all the analyzed southwestern viruses belong to the Andes lineage. Although human infection principally occurs via inhalation of contaminated rodent excreta, our results with Andes virus show the first direct genetic evidence of person-to-person transmission of a hantavirus.

Genetic characterization and phylogeny of Andes virus and variants from Argentina and Chile.

Andes virus, one of five hantaviruses known to cause hantavirus pulmonary syndrome (HPS), emerged in 1995 in southwestern Argentina (López et al. (1996) Virology 220, 223-226). The complete nucleotide sequence of Andes virus S genome segment was determined and compared with sequences of viral RNAs in autopsy tissues of more recently reported HPS cases from southwestern Argentina and south of Chile (cases ESQ H-1/96 and CH H-1/96). Andes virus S segment was found to be 1876 nucleotides in length and to encode the nucleocapsid protein (N), 428 amino acids in length. S segment analysis also revealed a long 5' non-coding region (547 nucleotides) which displays three copies of an octanucleotide sequence repeat. Comparisons of S segment sequences of ESQ H-1/96 and CH H-1/96 (82% of the entire genome sequence) with the corresponding sequences of Andes virus revealed identities of 97.2% and 98.5%, respectively. Sequence motifs identical and in the same positions as exhibited in Andes virus 5' non-coding region were found in both, ESQ H-1/96 and CH H-1/96 sequences. Three genome fragments of the M segment sequence of the viruses (representing approximately 34% of the entire sequence) were also analyzed. Comparisons of S and M segment sequences of Andes virus with the corresponding sequences of ESQ H-1/96 showed S and M segment identities which differ by less than 1.4%. Andes virus and CH H-1/96 have S segments that differ by 1.5% from one another while their M segment fragments differ by 5.5-8.2%. Phylogenetic analysis showed that Andes virus along with ESQ H-1/96 and CH H-1/96 form a distinct lineage within the clade containing Bayou and Black Creek Canal viruses. It also showed that Andes virus branch of trees derived from comparisons of S or M sequences differed. It is concluded that Andes virus variants causing HPS circulate east and west of the Andes mountains.

Collective binding properties of receptor arrays.

Binding kinetics of receptor arrays can differ dramatically from that of the isolated receptor. We simulate synaptic transmission using a microscopically accurate Brownian dynamics routine. We study the factors governing the rise and decay of the activation probability as a function of the number of transmitter molecules released. Using a realistic receptor array geometry, the simulation reproduces the time course of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-mediated excitatory postsynaptic currents. A consistent interpretation of experimentally observed synaptic currents in terms of rebinding and spatial correlations is discussed.

Development of a murine model of chronic Salmonella infection.

The invasive disease caused by Salmonella typhimurium in mice resembles the acute phase of human typhoid fever caused by Salmonella typhi, and experimental murine salmonellosis is a widely used experimental model for systemic salmonellosis. In this paper we demonstrate that murine S. typhimurium infection can also be used to model the development of the chronic carrier state that develops in humans after infection with S. typhi. We describe a virulent variant of S. typhimurium that has decreased expression of AgfA fibers under all environmental conditions studied and that causes a chronic carrier state in BALB/c mice after peroral inoculation. The chronic carrier state is associated with persistence of bacteria in the small intestine, spleen, and liver, and chronic infection continues despite the development of protective immunity to challenge with virulent Salmonella.

Hantavirus pulmonary syndrome in Argentina. Possibility of person to person transmission.

In March 1995 the first case of a familiar outbreak of Hantavirus pulmonary syndrome (HPS) was notified in El Bolson, in the South of Argentina. Until December 15, 1996, a total of 77 cases of HPS had been notified with 48% mortality, distributed in three geographical areas of the country, South, North and Center. During 1996, of the 19 cases from El Bolsón, three were local physicians, one of whom -during the prodrome of her illness- travelled to Buenos Aires to be attended. In the hospital, two of the physicians who assisted her, developed HPS 27 and 28 days after the first contact. These data suggest for the first time the possibility of interhuman transmission of the Hantavirus responsible for the pulmonary syndrome.

Geometric and many-particle aspects of transmitter binding.

We investigate the various reactivity patterns possible when several transmitter molecules, released at one side of a synaptic gap, diffuse and bind reversibly to a single receptor at the other end. In the framework of a one-dimensional approximation, the complete time, reactivity, concentration and gap-width dependence are determined, using a rigorous theoretical and computational approach to the many-body aspects of this problem. The time dependence of the survival probability is found to consist of up to four phases. These include a short delay followed by gaussian, power-law, and exponential decay phases. A rigorous expression is derived for the long-time exponent and approximate expressions are obtained for describing the short-time gaussian phase.

Self-arrangement of molybdenum particles into cubes.

An unusual distribution of particle sizes has been observed following the formation of molybdenum particles by argon ion sputtering. Many of the molybdenum particles produced by sputtering at the threshold pressure for particle formation in the vapor appear to be single crystalline cubes. There are two prominent peaks in the edge length distribution of the cubes, one centered at 4.8 nanometers with a halfwidth of approximately 1.3 nanometers and the other at 17.5 nanometers. The peak for the larger cubes is approximately square and has a total width of 7.0 nanometers. Evidence is presented that the larger cubes are formed by a 3 by 3 by 3 self-arrangement of the smaller cubes, which contain approximately 7000 atoms. Self-arrangement in inorganic structures is normally only observed when the building blocks are atoms, molecules, or clusters of less than 100 atoms.

Postirradiation hemangiosarcoma of the chest wall. Report of a case.

An unusual case of cutaneous hemangiosarcoma that developed on a chest wall irradiated after mastectomy for cancer is described. The patient, an elderly woman, had previously received high-dose radiation to the chest wall as well as systemic combination chemotherapy. Sarcoma developed 6 years after mastectomy and progressed rapidly. The time between radiation therapy and occurrence of cutaneous sarcoma was shorter than the median latent period reported for development of radiation-induced sarcoma. Thus, we cannot be certain that radiation was the true or sole etiologic factor. Whether the addition of systemic chemotherapy was a contributory agent is also speculative.

Observed range of assay values for plasma and cerebrospinal fluid amino acid levels in infants and children aged 3 months to 10 years.

From data collected at the Children's Hospital, Vancouver, during a two year period, 1976 - 1977, we have determined a range of values for children aged 3 months to 6 years for 24 plasma amino acids and for children aged 3 months to 10 years for 18 cerebrospinal fluid amino acids. A total of 26 plasma and 21 cerebrospinal fluid samples were accepted for our reference population. Six of the children in the plasma group were also in the cerebrospinal fluid group, making a total of 39 children in the study.

Peliosis hepatis in hematologic disease. Report of two cases.

Two patients with hematologic disease, one of whom had received androgenic steroids, had liver damage associated with peliosis hepatis. In one patient with spherocytic hemolytic anemia, peliosis hepatis was an incidental postmortem finding. In the other patient, who was treated with androgenic-anabolic steroids for aplastic anemia, hepatic failure associated with peliosis hepatis developed. Splenic involvement by peliosis was present in both patients. Peliosis hepatis should be considered in the differential diagnosis of hepatic disease in patients with hematologic disorders, especially if treatment has included androgenic-anabolic steroids.

Adult severe combined immunodeficiency and sarcoid-like granulomas with hypersplenism.

A patient presented with lymphopenia, anergy, hypogammaglobulinemia and hypersplenism. Histologic examination of the spleen and lymph node revealed noncaseating sarcoid-like granulomas. Despite a significant rise in circulating lymphocytes after splenectomy there was in vivo and in vitro evidence of B- and T-lymphocyte dysfunction. A histologic picture mimicking sarcoidosis may occur in patients with immune deficiency. The granulomatous proliferation may represent an altered host response to antigen.

Pulsed Doppler ultrasound detection of flow disturbances in arteriosclerosis.

Pulsed Doppler ultrasound blood flow detection has been used in a noninvasive manner to detect arterial abnormalities associated with arteriosclerosis. Sound spectrograms of ultrasound signals obtained from in vitro and animal studies in which flow was disturbed by obstacles placed in the flow stream showed a different distribution of energy over frequency than signals obtained from studies with no flow disturbances. Similar findings were seen clinically. A technique has been developed which can detect disturbed flow patterns resulting from partial occlusion in important superficial arteries (e.g. femoral and carotid) up to 15 cm distal to localized arterial wall abnormalities. Thirty-five arterial examinations of normal and arteriographically abnormal arteries in 12 patients revealed a sensitivity of 83 percent and a specificity of 61 percent. This study suggests that pulsed Doppler ultrasound may be useful as a screening technique for detection of arteriosclerotic lesions in major superficial arteries.