Oligonucleotide microarray analysis of gene expression in neuroblastoma displaying loss of chromosome 11q

A number of distinct subtypes of neuroblastoma exist with different genetic abnormalities that are predicative of outcome. Whole chromosome gains are usually associated with low stage disease and favourable outcome, whereas loss of 1p, 3p and 11q, unbalanced gain of 17q and MYCN amplification (MNA) are indicative of high stage disease and unfavourable prognosis. Although MNA and loss of 11q appear to represent two distinct genetic subtypes of advanced stage neuroblastoma, a detailed understanding of how these subtypes differ in terms of global gene expression is still lacking. We have used metaphase comparative genomic hybridization (CGH) analysis in combination with oligonucleotide technology to identify patterns of gene expression that correlate with specific genomic imbalances found in primary neuroblastic tumours and cell lines. The tumours analysed in this manner included a ganglioneuroma, along with various ganglioneuroblastoma and neuroblastoma of different stages and histopathological classifications. Oligonucleotide microarray-based gene expression profile analysis was performed with Affymetrix HU133A arrays representing approximately 14 500 unique genes. The oligonucleotide microarray results were subsequently validated by quantitative real-time PCR, immunohistochemical staining, and by comparison of specific gene expression patterns with published results. Hierarchical clustering of gene expression data distinguished tumours on the basis of stage, differentiation and genetic abnormalities. A number of genes were identified whose patterns of expression were highly correlated with 11q loss; supporting the concept that loss of 11q represents a distinct genetic subtype of neuroblastoma. The implications of these results in the process of neuroblastoma development and progression are discussed.

Expression and prognostic relevance of Mcl-1 in breast cancer

BACKGROUND

Bcl-2, an anti-apoptotic protein, is frequently associated with favourable prognosis in breast cancer. The potential role of mcl-1, another bcl-2 family member, in breast cancer has not yet been defined.

PATIENTS AND METHODS

This study examined the expression of mcl-1 and bcl-2 in 170 cases of invasive primary breast carcinoma, using reverse-transcriptase polymerase chain reaction and immunohistochemical analyses.

RESULTS

Expression of bcl-2 mRNA and protein were found to be favourably associated with outcome for patients, supporting a prognostic role for bcl-2 in breast cancer, whereas mcl-1 expression, at the mRNA or protein level, did not correlate with tumour size, grade, lymph node or ER status, age of patient at diagnosis, or disease outcome.

CONCLUSION

As these analyses of mcl-1 expression may have co-detected mcl-1(S/deltaTM) (a more recently identified, shorter variant, that may be pro-apoptotic) with the anti-apoptotic wild-type of mcl-1, it is possible that future studies may indicate some significant clinical correlations if the isoforms can be independently investigated.

Lack of prognostic effect of Cox-2 expression in primary breast cancer on short-term follow-up

AIMS

Cyclo-oxygenase (Cox) catalyses the conversion of arachidonic acid into prostaglandins (PG) and other eciosanoids. The prostaglandins, especially PGE(2) are implicated in tumorigenesis via angiogenesis and suppression of immune reactivity. There are two known isoforms of the enzyme, Cox-1, which is constitutively expressed and the inducible isoform, Cox-2. Cox-2 is induced in response to inflammatory mediators, growth factors, oncogenes and mitogens. Non-selective Cox inhibitors may reduce the relative risk of colonic and breast carcinoma.

METHODS

We studied the expression of Cox-2 by immunohistochemistry in 106 primary breast carcinoma specimens collected over a three-year period, using a commercially available polyclonal antibody on formalin-fixed, paraffin-embedded tissue. The slides were examined independently by two pathologists. Tumours were classified according to accepted criteria and an immunohistochemical score (IHS) was calculated for each specimen. The IHS combines the percentage of immunoreactive cells (quantity score) and an estimate of staining intensity (staining intensity score).

RESULTS

All patients were female. The mean age was 53 years, range 28-86 years. Forty percent (n=42) of tumours were node negative and 60% (n=64) node positive. Forty-nine percent (n=52) of tumours were grade 3, a further 49% (n=52) grade 2 and 2% (n=2) grade 1. There was no statistically significant correlation between IHS and tumour size, grade, histology, nodal status, estrogen receptor or progesterone receptor positivity. A trend was observed showing an IHS of zero is associated with prolonged survival compared with an IHS of 9-12.

CONCLUSION

Cox-2 expression in primary breast cancer does not correlate with accepted pathological or biochemical prognostic indicators.

Prognostic importance of survivin in breast cancer

Survivin is a member of the inhibitor of apoptosis (IAP) family, and is also involved in the regulation of cell division. Survivin is widely expressed in foetal tissues and in human cancers, but generally not in normal adult tissue. This study examined the expression of surviving protein in a series of 293 cases of invasive primary breast carcinoma. Survivin immunoreactivity was assessed using two different polyclonal antibodies, and evaluated semiquantitatively according to the percentage of cells demonstrating distinct nuclear and/or diffuse cytoplasmic staining. Overall, 60% of tumours were positive for survivin: 31% demonstrated nuclear staining only, 13% cytoplasmic only, and 16% of tumour cells demonstrated both nuclear and cytoplasmic staining. Statistical analysis revealed that survivin expression was independent of patient's age, tumour size, histological grade, nodal status, and oestrogen receptor status. In multivariate analysis, nuclear survivin expression was a significant independent prognostic indicator of favourable outcome both in relapse-free and overall survival (P<0.001 and P=0.01, respectively). In conclusion, our results show that survivin is frequently overexpressed in primary breast cancer. Nuclear expression is most common and is an independent prognostic indicator of good prognosis.

A study of women who stalk

OBJECTIVE

The authors examined whether female stalkers differ from their male counterparts in psychopathology, motivation, behavior, and propensity for violence.

METHOD

Female (N=40) and male (N=150) stalkers referred to a forensic mental health clinic were compared.

RESULTS

In this cohort, female stalkers were outnumbered by male stalkers by approximately four to one. The demographic characteristics of the groups did not differ, although more male stalkers reported a history of criminal offenses. Higher rates of substance abuse were also noted among the male stalkers, but the psychiatric status of the groups did not otherwise differ. The duration of stalking and the frequency of associated violence were equivalent between groups. The nature of the prior relationship with the victim differed, with female stalkers more likely to target professional contacts and less likely to harass strangers. Female stalkers were also more likely than male stalkers to pursue victims of the same gender. The majority of female stalkers were motivated by the desire to establish intimacy with their victim, whereas men showed a broader range of motivations.

CONCLUSIONS

Female and male stalkers vary according to the motivation for their pursuit and their choice of victim. A female stalker typically seeks to attain a close intimacy with her victim, who usually is someone previously known and frequently is a person cast in the professional role of helper. While the contexts for stalking may differ by gender, the intrusiveness of the behaviors and potential for harm does not.

Comparative genomics of Listeria species

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Stalking: new constructions of human behaviour

OBJECTIVE

In the last decade stalking has emerged as a significant social problem, which now constitutes a specific form of criminal offence in most English-speaking nations. This paper examines why stalking has become a major social problem and why it should be of particular concern to mental health professionals.

METHOD

Using the extant literature, the history of the emergence of stalking as social, legal and behavioural science discourses is presented. An attempt is made to understand the social and cultural forces which shaped our current understanding of the phenomenon of stalking.

RESULTS

Stalking flourishes in a variety of contexts; the social conditions conducive to such behaviour include greater instability in intimate relationships, a culture of blame and entitlement and a growing social anxiety that emphasizes vulnerability to crime and suspicion regarding the intentions of strangers. Stalking is now an established category whose utility is in directing social, legal and health energies to support victims and relieve stalkers of their burden of pursuit.

CONCLUSIONS

Stalking is a curious construction born of a range of tensions in contemporary culture but has proved to be a useful label and a useful concept. In part due to the emergence of the concept of stalking, laws are now available to protect, and services increasingly geared to support, the victims of persistent harassment.

Same-gender stalking

Although stalkers most commonly target victims of the opposite gender, the results of larger and less selective studies suggest that same-gender stalking occurs with greater frequency than formerly thought. This study reviews the exiguous literature on same-gender stalking and presents the findings from a clinical study of 29 same-gender stalking cases that were referred to a forensic psychiatry center. The demographic characteristics, behavior, motivations, and psychopathology of same-gender stalkers are compared with a sample of 134 opposite-gender stalkers. The two groups were similar in many respects, with some discrepancies evident in the prior relationship between victim and stalker, harassment methods, and stalking motives. The impact of same-gender stalking on its victims is examined, and the implications of these findings are discussed.

Abnormalities of internally generated saccades in obsessive-compulsive disorder

BACKGROUND

We aimed to utilize tests of saccadic function to investigate whether cognitive abnormalities in obsessive-compulsive disorder (OCD) arise from a dysfunction of inhibitory processes or whether they reflect a more general difficulty in guiding behaviour on the basis of an internal representation of task goal.

METHODS

Twelve patients with OCD and 12 matched controls performed a visually-guided saccade task, a volitional prosaccade task and an antisaccade task. The latency and gain of saccades was compared between groups for the three saccade tasks. The number of antisaccade errors was also calculated and compared between groups.

RESULTS

There was no difference for antisaccade error rates between the groups. The latency of visually guided saccades did not differ between groups, however the latency of both volitional prosaccades and antisaccades was significantly slower in the patients with OCD than in controls. The difference in latency between volitional prosacades and antisaccades, however, was equal between groups.

CONCLUSIONS

These results suggest that patients with OCD have an abnormality in guiding behaviour on the basis of an internal representation of the task goal, rather than a problem with inhibiting reflexive behaviour.

Impairment of olfactory identification in obsessive-compulsive disorder

BACKGROUND

Olfactory identification ability has been associated with processing in the orbitofrontal cortex (OFC), an area that has been implicated in the pathophysiology of obsessive-compulsive disorder (OCD). Although olfactory sensitivity is normal in patients with OCD, no study has investigated olfactory identification in this disorder.

METHODS

A group of 20 subjects with OCD and 23 age- and education-matched controls performed a standardized test of olfactory identification. They also performed computerized tests of spatial memory span, spatial working memory and spatial recognition memory that have been shown previously to be sensitive to cognitive deficits in patients with OCD.

RESULTS

Performance on the olfactory identification task, spatial recognition task and spatial span task was significantly worse in the OCD group than controls.

CONCLUSIONS

While impairment in spatial cognition is consistent with previous studies of OCD, its significance for brain-behaviour models of OCD is unclear. However, the finding of abnormal olfactory identification in patients with OCD is consistent with the hypothesis that there is a disruption to processing at the level of the OFC in the disorder.

Tourette's and comorbid syndromes: obsessive compulsive and attention deficit hyperactivity disorder. A common etiology?

Tourette's syndrome (TS), a neuropsychiatric movement disorder that manifests itself in childhood, is often associated with comorbid symptomatology, such as obsessions, compulsions, hyperactivity, distractibility, and impulsivity. Epidemiological studies suggest that a substantial number of TS patients develop clinical levels of obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD). This review aims to provide an integrated account of the three disorders in terms of their comorbidity. Neuroimaging studies suggest that all three disorders involve neuropathology of the basal-ganglia thalamocortical (BGTC) pathways: TS in the sensorimotor and limbic BGTC circuits; OCD in the prefrontal and limbic BGTC pathways; and ADHD in the sensorimotor, orbitofrontal, and limbic BGTC circuits. The pattern of comorbidity and other evidence indicates that the TS gene(s) may be responsible for a spectrum of disorders, including OCD and ADHD, but also that the disorders OCD and ADHD can exist in their own right with their own etiologies.

Study of stalkers

OBJECTIVE

This clinical study ws devised to elucidate the behaviors, motivations, and psychopathology of stalkers.

METHOD

It concerned 145 stalkers referred to a forensic psychiatry center for treatment.

RESULTS

Most of the stalkers were men (79%, N = 114), and many were unemployed (39%, N = 56); 52% (N = 75) had never had an intimate relationship. Victims included ex-partners (30%, N = 44), professional (23%, N = 34) or work (11%, N = 16) contacts, and strangers (14%, N = 20). Five types of stalkers were recognized: rejected, intimacy seeking, incompetent, resentful, and predatory. Delusional disorders were common (30%, N = 43), particularly among intimacy-seeking stalkers, although those with personality disorders predominated among rejected stalkers. The duration of stalking was from 4 weeks to 20 years (mean = 12 months), longer for rejected and intimacy-seeking stalkers. Sixty-three percent of the stalkers (N = 84) made threats, and 36% (N = 52) were assaultive. Threats and property damage were more frequent with resentful stalkers, but rejected and predatory stalkers committed more assaults. Committing assault was also predicted by previous convictions, substance-related disorders, and previous threats.

CONCLUSIONS

Stalkers have a range of motivations, from reasserting power over a partner who rejected them to the quest for a loving relationship. Most stalkers are lonely and socially incompetent, but all have the capacity to frighten and distress their victims. Bringing stalking to an end requires a mixture of appropriate legal sanctions and therapeutic interventions.

Viral clearance without destruction of infected cells during acute HBV infection

Viral clearance during hepatitis B virus (HBV) infection has been thought to reflect the destruction of infected hepatocytes by CD8(+) T lymphocytes. However, in this study, HBV DNA was shown to largely disappear from the liver and the blood of acutely infected chimpanzees long before the peak of T cell infiltration and most of the liver disease. These results demonstrate that noncytopathic antiviral mechanisms contribute to viral clearance during acute viral hepatitis by purging HBV replicative intermediates from the cytoplasm and covalently closed circular viral DNA from the nucleus of infected cells.

Stalking: false claims of victimisation

BACKGROUND

False allegations of victimisation although uncommon are important to recognise. This paper examines those who falsely claim to have been the victims of stalking.

AIMS

To highlight the phenomenon of false victims of stalking.

METHOD

Twelve individuals who falsely claimed to be victims of stalking were compared with a group of 100 true stalking victims.

RESULTS

False stalking victims presented for help earlier than real victims and were less likely to claim harassment via letters. They reported equivalent levels of violence directed at themselves but seldom claimed others were attacked. Five types of false claimants were recognisable. False victims consumed more medical services than genuine stalking victims and they were more likely to be embroiled in legal action. They reported similar levels of distress with suicidal ruminations in over 40%.

CONCLUSIONS

The current interest in stalking is promoting false claims of being stalked. Early identification of these cases and appropriate intervention are essential to both minimising abuses of resources available to true victims and equally to ensure appropriate care for those who express their own disordered state in false claims of victimisation.

Human class I supertypes and CTL repertoires extend to chimpanzees

Using an in vitro peptide stimulation strategy, two chimpanzees that were acutely infected by the hepatitis B virus (HBV) produced peripheral blood CTL responses to several HBV-encoded epitopes that are known to be recognized by class I-restricted CTL in acutely infected humans. One animal responded to three HBV peptides that, in humans, are restricted by HLA-A2; the other animal responded to three peptides that are restricted by HLA-B35 and HLA-B51, members of the HLA-B7 supertype in man. The peptides recognized by each chimp corresponded with the ability of its class I molecules to bind peptides containing the HLA-A2 and HLA-B7 supermotifs. Similar, apparently class I-restricted CTL responses to some of these peptides were also detected in occasional HBV-uninfected chimps. These results demonstrate that the CTL repertoire overlaps in humans and chimps and that the HLA-A2 and HLA-B7 supertypes extend to the chimpanzee. Based on these results, the immunogenicity and efficacy of vaccines designed to induce CTL responses to human HLA-restricted viral epitopes may be testable in chimpanzees.

Neuropsychological deficits in obsessive-compulsive disorder: a comparison with unipolar depression, panic disorder, and normal controls

BACKGROUND

The neuropsychological dysfunction associated with obsessive-compulsive disorder (OCD) has similarities to the deficits reported in other affective or anxiety disorders. We directly compared cognitive function in patients with OCD with that in matched patients with unipolar depression and panic disorder and healthy control subjects to establish the specific nature of neuropsychological deficits in OCD.

METHODS

Thirty patients with OCD, 30 patients with panic disorder, 20 patients with unipolar depression, and 30 controls completed a computerized neuropsychological battery that assessed the accuracy and latency of executive, visual memory, and attentional functions.

RESULTS

The groups did not differ according to age, years of education, or estimated IQ. However, we found group differences in cognitive performance. The patients with OCD were impaired on measures of spatial working memory, spatial recognition, and motor initiation and execution. In contrast, performance of these tasks by patients with panic disorder or depression did not differ from that of controls. There were no group differences for performance on the measures of planning, cognitive speed, pattern recognition, and delayed matching to sample, although patients with depression were impaired for attentional set shifting.

CONCLUSIONS

Neuropsychological deficits were observed in patients with OCD that were not observed in matched patients with panic disorder or unipolar depression. As such, the cognitive dysfunction in OCD appears to be related to the specific illness processes associated with the disorder.

Cognitive deficits in obsessive-compulsive disorder on tests of frontal-striatal function

BACKGROUND

Although neuropsychological and neuroimaging studies of obsessive-compulsive disorder (OCD) have implicated the frontal cortex and subcortical structures in the pathophysiology of the disorder, few studies have examined cognitive function in patients with OCD on tasks validated in the assessment of frontal lobe and subcortical dysfunction.

METHODS

The accuracy and latency of executive and visual memory function was assessed in 23 nondepressed OCD patients and 23 normal healthy controls matched for age, sex, education, and estimated IQ.

RESULTS

The patients with OCD performed within the normal range on tasks of short-term memory capacity, delay dependent visual memory, pattern recognition, attentional shifting, and planning ability; however, specific cognitive deficits related to spatial working memory, spatial recognition, and motor initiation and execution were observed in the patient group. These deficits were not correlated with aspects of the patients' intellectual functioning or comorbid psychological symptoms, suggesting that the impairments were related to the specific clinical features of OCD.

CONCLUSIONS

Patients with OCD showed specific cognitive deficits on tasks of executive and visual memory function. The pattern of impaired performance in these patients was qualitatively similar to the performance of patients with frontal lobe excisions and subcortical pathology on the same test battery, suggesting that the underlying pathophysiology of the disorder could best be conceptualized as reflecting dysfunction of frontal-striatal systems.

Neuropsychological function in young patients with unipolar major depression

BACKGROUND

While neuropsychological studies have consistently reported impaired cognition in elderly patients with unipolar depression, studies of cognitive function in younger patients with depression have produced equivocal results. The aim of this study was to examine the presence and nature of cognitive deficits in young patients with depression.

METHODS

Neuropsychological function was assessed in 20 young patients with unipolar depression, in comparison to 20 age-, education- and IQ- matched controls. Subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were employed, as this battery has proved sensitive to deficits in middle-aged and elderly patients with depression.

RESULTS

The patients were not impaired for short-term memory capacity, spatial working memory, planning ability, cognitive speed, delayed matching to sample or recognition memory. Compared to controls, the patients showed impaired subsequent movement latencies on the Tower of London task, suggesting deficits in the ability to sustain motor responses in depression. The depression group were also impaired on the task of attentional set shifting, requiring more trials to criterion at the intradimensional stage of the task and being more likely to fail the task at the extradimensional shift stage than controls. Further analysis indicated that half of the depression group failed to complete all stages of the set shifting task. These patients were more likely to have required in-patient hospitalization at some time during their illness.

CONCLUSIONS

These results indicate that there are specific cognitive deficits in young patients with depression and that their presence may be related to a history of hospitalization.

Powered functional endoscopic sinus surgery

The use of powered instrumentation in functional endoscopic sinus surgery has been a revolutionary development in the surgical treatment of chronic sinusitis. Several studies have demonstrated the safety, efficacy, and ease of use of this new technique. To provide support and coordinate the surgical process in powered functional endoscopic sinus surgery procedures, perioperative nurses must have an appreciation for its specific equipment handling and for appropriate patient care. This article describes a specific protocol that perioperative nurses can use to facilitate efficient and safe surgical environments for patients who undergo powered endoscopic sinus surgery procedures.

The hepatitis C virus: overview

Our knowledge of hepatitis C virus (HCV) dates only from 1975, when non-A, non-B hepatitis was first recognized. It was not until 1989 that the genome of the virus was first cloned and sequenced, and expressed viral antigens used to develop serological assays for screening and diagnosis. HCV is in a separate genus of the virus family Flaviviridae. It is a spherical enveloped virus of approximately 50 nm in diameter. Its genome is a single-stranded linear RNA molecule of positive sense and consists of a 5' noncoding region, a single large open reading frame, and a 3' noncoding region. The open reading frame encodes at least three structural and six nonstructural proteins. The genome is characterized by significant genetic heterogeneity, based on which HCV isolates can be classified into six major genotypes and more than 50 subtypes. Even individual isolates of HCV are genetically heterogeneous (quasispecies diversity). Genetic heterogeneity of HCV is greatest in the amino-terminal end of the second envelope protein (hypervariable region 1). This region may represent a neutralization epitope that is under selective pressure from the host's humoral immune response. Infection with HCV proceeds to chronicity in more than 80% of cases, and even recovery does not protect against subsequent re-exposure to the virus. The development of a broadly protective vaccine against HCV will therefore require a better understanding of the molecular biology and immune response to this virus.

Acute viral hepatitis in Saudi Arabia: seroepidemiological analysis, risk factors, clinical manifestations, and evidence for a sixth hepatitis agent

We conducted a prospective, descriptive cohort study of all 217 cases of acute viral hepatitis (AVH) seen in adults during 1992 at the sole hospitals with infectious disease departments in the second and third largest cities in the Kingdom of Saudi Arabia. In addition, we undertook a nested case-control study. Our goals were (1) to determine the causes, demographics, risk factors, and clinical characteristics of AVH in the Kingdom; (2) to evaluate the reliability of diagnostic tests for acute hepatitis C and E; and (3) to assess the relative importance, characteristics, and risk factors of a sixth hepatitis agent, non-A-E. All cases and controls completed a questionnaire. Cases provided blood samples for studies of serum bilirubin, alanine and aspartate aminotransferases, and antibody to hepatitis viruses as well as genome detection studies. The results of serological and molecular tests were used to categorize each case as hepatitis A, B, C, D, E, or non-A-E. Historical, clinical, and laboratory determinants were statistically analyzed by comparisons between groups with different types of AVH and controls. Analysis of risk factors suggested that hepatitis C and D were parenterally transmitted, while hepatitis A, E, and non-A-E were not; the route of transmission of hepatitis B was unclear. Hepatitis E was strongly associated with living or traveling on the Indian subcontinent. The clinical disease caused by all six agents was indistinguishable. The putative sixth agent caused 13% of cases. The second-generation tests for antibody to HCV and HEV were relatively reliable for the diagnosis of AVH.

Structural and functional characterization of human immunodeficiency virus tat protein

Site-directed mutagenesis was used to identify functional domains present within the human immunodeficiency virus (HIV) tat protein. Transient cotransfection experiments showed that derivatives of tat protein with amino acid substitutions either at the amino-terminal end or at cysteine residue 22, 37, 27, or 25 were no longer able to transactivate HIV long terminal repeat-directed gene expression. Incubation of Tat expressed in Escherichia coli with zinc demonstrated that both authentic Tat and cysteine mutation derivatives could form metal-protein complexes. The tat proteins that contained alterations within the cluster of positively charged amino acid residues retained their ability to transactivate gene expression, albeit at markedly reduced levels. Indirect immunofluorescence showed that the authentic tat protein and the amino-terminal and cysteine substitution mutants all localized in the nucleus, with accumulation being most evident in the nucleolus. In contrast, nuclear accumulation was greatly reduced with the basic-substitution mutations. Consistent with this result, a fusion protein that contained amino acids GRKKR, derived from the basic region, fused to the amino-terminal end of beta-galactosidase also accumulated within the nucleus. These results demonstrate that the 14-kilodalton tat protein contains at least three distinct functional domains affecting localization and transactivation.

Genetic relatedness among animal rotaviruses

The genomic relatedness among representative rotavirus strains was examined by employing cross-hybridization techniques. Single stranded (ss) RNA prepared by in vitro transcription of purified rotavirus particles and labeled with either 32P or 125I was hybridized to denatured genomic, double stranded (ds) RNAs. The hybrids formed were analyzed by polyacrylamide gel electrophoresis (PAGE) or by testing their sensitivity to digestion with single strand specific nuclease (S-1 nuclease). A relatively high degree of genomic homology was found to exist among several bovine rotavirus strains obtained from different geographical areas. Similarly, a high degree of homology was found between two different simian rotavirus strains, and also between two porcine strains. The human Wa strain exhibited a low degree of genomic homology with simian, bovine and canine strains whereas a higher level of homology was detected between the human Wa strain and the porcine strains. The observed RNA sequence divergences of rotaviruses isolated from different animal species are in agreement with the restricted host range of these viruses and their known antigenic differences and suggest a divergent evolution of their genomes.

Mycotic aneurysms in intravenous drug abuse

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