Comparison of the diagnostic yield of transbronchial lung biopsies by forceps and cryoprobe in diffuse parenchymal lung disease

Background

Transbronchial lung cryobiopsy (TBLC) in the diagnosis of diffuse parenchymal lung disease (DPLD) has shown a promising yield in recent times, with low post-procedural mortality and morbidity.

Objectives

To compare the yield of TBLC and conventional transbronchial forceps lung biopsy (TBLB).

Methods

A prospective study was carried out in patients with DPLD over a period of 1 year in a tertiary respiratory care institute in New Delhi, India. All 87 patients enrolled underwent both TBLB and TBLC. The procedures were performed in the bronchoscopy suite under conscious sedation and local anaesthesia, with an attempt to take a minimum of three biopsy specimens by conventional TBLB followed by TBLC. A 1.9 mm cryoprobe with a freezing time of 4 - 5 seconds was used. An Arndt endobronchial blocker was used to control bleeding along with locally administered medications.

Results

TBLB and TBLC led to a definitive diagnosis in 27 (31.0%) and 69 (79.3%) cases, respectively. The commonest diagnoses were hypersensitivity pneumonitis, sarcoidosis and pulmonary tuberculosis. TBLC led to additional diagnoses in 42 cases (48.3%). Pneumothorax was observed in 12 cases (13.8%), and moderate bleeding occurred in 63 (72.4%). There were no procedure-related deaths.

Conclusion

TBLC had a better diagnostic yield than conventional TBLB in DPLD. It has the potential to become a safe day-care procedure in a resource-limited setting, if certain precautions are taken.

Study synopsis

What the study adds. Compared with transbronchial forceps lung biopsy, transbronchial lung cryobiopsy (TBLC) led to additional diagnoses in 42 (48.3%) of 87 patients with clinicoradiological features of diffuse parenchymal lung disease. Pneumothorax was observed in 12 cases (13.8%) and moderate bleeding in 63 (72.4%). TBLC without rigid bronchoscopy or advanced airway devices under conscious sedation had a good diagnostic yield with an acceptable adverse events profile.Implications of the findings. TBLC under conscious sedation is not resource intensive and can be carried out in settings with limited resources.

Risk factors for early mortality in patients with pulmonary tuberculosis admitted to the emergency room

BACKGROUND AND OBJECTIVES

Mortality of patients with pulmonary tuberculosis (TB) admitted to emergency departments is high. This study was aimed at analysing the risk factors associated with early mortality and designing a risk score based on simple parameters.

METHODS

This prospective case-control study enrolled patients admitted to the emergency department of a referral TB hospital. Clinical, radiological, biochemical and microbiological risk factors associated with death were compared among patients dying within one week from admission (cases) and those surviving (controls).

RESULTS

Forty-nine of 250 patients (19.6%) experienced early mortality. Multiple logistic regression analysis showed that oxygen saturation (SaO₂) ≤90%, severe malnutrition, tachypnoea, tachycardia, hypotension, advanced disease at chest radiography, severe anaemia, hyponatremia, hypoproteinemia and hypercapnia were independently and significantly associated with early mortality. A clinical scoring system was further designed to stratify the risk of death by selecting five simple parameters (SpO₂ ≤ 90%, tachypnoea, hypotension, advanced disease at chest radiography and tachycardia). This model predicted early mortality with a positive predictive value of 94.88% and a negative predictive value of 19.90%.

CONCLUSIONS

The scoring system based on simple parameters may help to refer severely ill patients early to a higher level to reduce mortality, improve success rates, minimise the need for pulmonary rehabilitation and prevent post-treatment sequelae.

Multiple pterygium syndrome: Challenge for anesthesiologist

Multiple pterygium syndrome (MPS) is a very rare autosomal recessive disorder characterized by flexion of joint and digit contractures, skin webbing, cleft palate, deformity of the spine, and cervical spine fusion. Difficult airway is associated mainly due to micrognathia, retrognathia, webbing of the neck, and limitation of the mouth opening and neck extension. We are reporting a case of a 5-year-old female diagnosed with MPS and exhibiting a bilateral club foot and congenital vertical talus. The patient was posted for manipulation and above the knee casting under general anesthesia.

Inadvertent intrathecal injection of labetalol

Labetalol is a combined α and β adrenergic receptor blocker. It is used to treat hypertension, especially in pregnant patients. We report a case of a female patient who was given labetalol intrathecally in place of bupivacaine due to a similar appearance of ampoules which resulted in a drop in blood pressure and pulse rate. The patient responded to fluid resuscitation and there occurred no neurological sequelae.

P16: CARDIAC ARREST AS A CONSEQUENCE OF AIR EMBOLISM STATUS POST CT-GUIDED LUNG BIOPSY

Purpose of Study

CT-guided transthoracic lung biopsy (CTLB) is a widely used procedure for the diagnosis of pulmonary lesions. Complication of air embolism has an incidence of 0.02%–0.06%. We report a fatal case of air embolism in the left atrium as a consequence of CTLB.

Methods Used

A 82 years old white female who presented to the radiology department for further evaluation of a recently diagnosed right lung mass. Shortly following CTLB she became unresponsive and developed cardiopulmonary arrest. Cardio-pulmonary resuscitation (CPR) was performed according to ACLS guidelines. She was successfully resuscitation and admitted to the ICU.CT chest was performed immediately after resuscitation which showed frothy air dense material in the left atrium and one of the right pulmonary veins suggesting a Broncho venous fistula with air embolism. Patient was subsequently sent to hyperbaric oxygen chamber which she tolerated well. A repeat CT chest and head failed to depict any evidence of air embolism. She was successfully weaned from the mechanical ventilation and extubated the following day.

Summary of Results

Air embolism following CTLB has a reported incidence of 0.02 to 0.06 but has catastrophic consequences if diagnosis is not made in a timely manner. The amount of air entry into the system is directly proportional to the severity of the patients symptoms. The mechanism of air entry in our patient was secondary to iatrogenic bronchovenous fistula.

Conclusions

Despite such rarity and fatal complication, clinicians should be aware of systemic air embolus after lung biopsy and be ready to provide emergent management for the treatment of the patient.

Abstract P16 Figure 1

Air within the Left atrium with evidence of air fluid level

Reconfigurable logic via gate controlled domain wall trajectory in magnetic network structure

An all-magnetic logic scheme has the advantages of being non-volatile and energy efficient over the conventional transistor based logic devices. In this work, we present a reconfigurable magnetic logic device which is capable of performing all basic logic operations in a single device. The device exploits the deterministic trajectory of domain wall (DW) in ferromagnetic asymmetric branch structure for obtaining different output combinations. The programmability of the device is achieved by using a current-controlled magnetic gate, which generates a local Oersted field. The field generated at the magnetic gate influences the trajectory of the DW within the structure by exploiting its inherent transverse charge distribution. DW transformation from vortex to transverse configuration close to the output branch plays a pivotal role in governing the DW chirality and hence the output. By simply switching the current direction through the magnetic gate, two universal logic gate functionalities can be obtained in this device. Using magnetic force microscopy imaging and magnetoresistance measurements, all basic logic functionalities are demonstrated.

Breaking up prolonged sitting reduces resting blood pressure in overweight/obese adults

AIM

To compare the effect of 7 h of prolonged sitting on resting blood pressure with a similar duration of sitting combined with intermittent brief bouts of light-intensity or moderate-intensity physical activity.

METHODS AND RESULTS

Overweight/obese adults (n = 19; aged 45-65 years) were recruited for a randomized three-treatment crossover trial with a one-week washout between treatments: 1) uninterrupted sitting; 2) sitting with 2 min bouts of light-intensity walking at 3.2 km/h every 20 min; and, 3) sitting with 2 min bouts of moderate-intensity walking at between 5.8 and 6.4 km/h every 20 min. After an initial 2 h period seated, participants consumed a test meal (75 g carbohydrate, 50 g fat) and completed each condition over the next 5 h. Resting blood pressure was assessed oscillometrically every hour as a single measurement, 5 min prior to each activity bout. GEE models were adjusted for sex, age, BMI, fasting blood pressure and treatment order. After adjustment for potential confounding variables, breaking up prolonged sitting with light and moderate-intensity activity breaks was associated with lower systolic blood pressure [light: 120 ± 1 mmHg (estimated marginal mean ± SEM), P = 0.002; moderate: 121 ± 1 mmHg, P = 0.02], compared to uninterrupted sitting (123 ± 1 mmHg). Diastolic blood pressure was also significantly lower during both of the activity conditions (light: 76 ± 1 mmHg, P = 0.006; moderate: 77 ± 1 mmHg, P = 0.03) compared to uninterrupted sitting (79 ± 1 mmHg). No significant between-condition differences were observed in mean arterial pressure or heart rate.

CONCLUSION

Regularly breaking up prolonged sitting may reduce systolic and diastolic blood pressure.

TRIAL REGISTRATION NUMBER

ACTRN12609000656235 (http://www.anzctr.org.au) TRIAL REGISTRATION DATE: August 4th 2009.

Coverage from Ontario, Canada's school-based HPV vaccine program: the first three years

BACKGROUND

In 2007, Ontario implemented a school-based human papillomavirus (HPV) vaccination program targeting grade 8 girls. Girls may complete the series in grade 9 (extended eligibility). Limitations in the existing provincial data sources for assessing HPV vaccine coverage in Ontario prompted the use of two surveys of Health Units (HUs) to calculate provincial vaccine coverage for the first three years of the vaccination program.

METHODS

We surveyed Ontario's 36 HUs in March and November 2011 to obtain vaccine coverage information, including source of denominator data, and use of local information systems. The second survey was necessary in order to assess coverage including extended eligibility for the third year. HU-reported HPV vaccine coverage was compared to coverage estimates obtained from two provincial systems: the Immunization Records Information System (IRIS) and the HPV reimbursement database, a system used to remunerate HUs for HPV vaccine doses administered.

RESULTS

100% of HUs participated in the two surveys. The provincial coverage estimates using HU-reported data were: 51% (2007-2008), 58% (2008-2009), and 59% (2009-2010) with large variation by HU. Coverage increased significantly over time. The number of HUs that were able to report on doses given as part of extended eligibility also increased over time (47% in 2007-2008 to 89% in 2009-2010; p=0.0008). Comparisons across the three data sources (survey, IRIS and reimbursement database) revealed significantly different coverage estimates. Class or school lists were the most common source of denominator data used by HUs (27/36, 75%), however independent schools were not included by all.

CONCLUSIONS

As not all HUs were able to report on HPV vaccine coverage including extended eligibility doses these findings likely underestimate the true coverage attained by Ontario's program. Although coverage is below the Canadian Immunization Committee benchmark of 80% within two years of program implementation, the upward trend in coverage is encouraging.

Association between the 2008-09 seasonal influenza vaccine and pandemic H1N1 illness during Spring-Summer 2009: four observational studies from Canada

BACKGROUND

In late spring 2009, concern was raised in Canada that prior vaccination with the 2008-09 trivalent inactivated influenza vaccine (TIV) was associated with increased risk of pandemic influenza A (H1N1) (pH1N1) illness. Several epidemiologic investigations were conducted through the summer to assess this putative association.

STUDIES INCLUDED

(1) test-negative case-control design based on Canada's sentinel vaccine effectiveness monitoring system in British Columbia, Alberta, Ontario, and Quebec; (2) conventional case-control design using population controls in Quebec; (3) test-negative case-control design in Ontario; and (4) prospective household transmission (cohort) study in Quebec. Logistic regression was used to estimate odds ratios for TIV effect on community- or hospital-based laboratory-confirmed seasonal or pH1N1 influenza cases compared to controls with restriction, stratification, and adjustment for covariates including combinations of age, sex, comorbidity, timeliness of medical visit, prior physician visits, and/or health care worker (HCW) status. For the prospective study risk ratios were computed. Based on the sentinel study of 672 cases and 857 controls, 2008-09 TIV was associated with statistically significant protection against seasonal influenza (odds ratio 0.44, 95% CI 0.33-0.59). In contrast, estimates from the sentinel and three other observational studies, involving a total of 1,226 laboratory-confirmed pH1N1 cases and 1,505 controls, indicated that prior receipt of 2008-09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring-summer 2009, with estimated risk or odds ratios ranging from 1.4 to 2.5. Risk of pH1N1 hospitalization was not further increased among vaccinated people when comparing hospitalized to community cases.

CONCLUSIONS

Prior receipt of 2008-09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring-summer 2009 in Canada. The occurrence of bias (selection, information) or confounding cannot be ruled out. Further experimental and epidemiological assessment is warranted. Possible biological mechanisms and immunoepidemiologic implications are considered.

Micro-RNA-128 (miRNA-128) down-regulation in glioblastoma targets ARP5 (ANGPTL6), Bmi-1 and E2F-3a, key regulators of brain cell proliferation

High density micro-RNA (miRNA) arrays, fluorescent-reporter miRNA assay and Northern miRNA dot-blot analysis show that a brain-enriched miRNA-128 is significantly down-regulated in glioblastoma multiforme (GBM) and in GBM cell lines when compared to age-matched controls. The down-regulation of miRNA-128 was found to inversely correlate with WHO tumor grade. Three bioinformatics-verified miRNA-128 targets, angiopoietin-related growth factor protein 5 (ARP5; ANGPTL6), a transcription suppressor that promotes stem cell renewal and inhibits the expression of known tumor suppressor genes involved in senescence and differentiation, Bmi-1, and a transcription factor critical for the control of cell-cycle progression, E2F-3a, were found to be up-regulated. Addition of exogenous miRNA-128 to CRL-1690 and CRL-2610 GBM cell lines (a) restored 'homeostatic' ARP5 (ANGPTL6), Bmi-1 and E2F-3a expression, and (b) significantly decreased the proliferation of CRL-1690 and CRL-2610 cell lines. Our data suggests that down-regulation of miRNA-128 may contribute to glioma and GBM, in part, by coordinately up-regulating ARP5 (ANGPTL6), Bmi-1 and E2F-3a, resulting in the proliferation of undifferentiated GBM cells.

Ubiquitin E3 ligase WWP1 as an oncogenic factor in human prostate cancer

The gene for E3 ubiquitin ligase WWP1 is located at 8q21, a region frequently amplified in human cancers, including prostate cancer. Recent studies have shown that WWP1 negatively regulates the TGFbeta tumor suppressor pathway by inactivating its molecular components, including Smad2, Smad4 and TbetaR1. These findings suggest an oncogenic role of WWP1 in carcinogenesis, but direct supporting evidence has been lacking. In this study, we examined WWP1 for gene dosage, mRNA expression, mutation and functions in a number of human prostate cancer samples. We found that the WWP1 gene had copy number gain in 15 of 34 (44%) xenografts and cell lines from prostate cancer and 15 of 49 (31%) clinical prostate cancer samples. Consistently, WWP1 was overexpressed in 60% of xenografts and cell lines from prostate cancer. Mutation of WWP1 occurred infrequently in prostate cancer. Functionally, WWP1 overexpression promoted colony formation in the 22Rv1 prostate cancer cell line. In PC-3 prostate cancer cells, WWP1 knockdown significantly suppressed cell proliferation and enhanced TGFbeta-mediated growth inhibition. These findings suggest that WWP1 is an oncogene that undergoes genomic amplification at 8q21 in human prostate cancer, and WWP1 overexpression is a common mechanism involved in the inactivation of TGFbeta function in human cancer.

Oral exfoliative cytology of smokers at discrete clinical stages using AgNOR staining

OBJECTIVE

This study was designed to evaluate oral exfoliative cytology of smokers without any clinically evident lesion and smokers with leukoplakia or oral cancer using AgNOR staining.

STUDY DESIGN

Cytological smears of 30 smokers without lesion, 30 smokers with leukoplakia, 30 smokers with oral cancer and 30 non-smokers (control group) were studied using one step silver staining method. The AgNOR count was established on 100 cells. Mean AgNOR count and mean % of cells with 5 or more AgNORs was evaluated. The count values of groups were compared and analysed using Student's unpaired t-test.

RESULTS

The mean AgNOR count for control group was 2.94 +/- 0.325, smokers without lesion 3.79 +/- 0.480 smokers with leukoplakia 3.89 +/- 0.433 and oral cancer 4.96 +/- 0.467. Mean % of cells with 5 or more AgNORs was 11.7, 26.5, 30.2 and 55.8 for control group, smokers without lesion, smokers with leukoplakia and oral cancer respectively.

CONCLUSION

Analysis of AgNORs suggest that smoking influences proliferative activity in cells of smokers without any clinical lesion and that oral cancer shows highest proliferative activity.

Relationship of Xba1 and EcoR1 polymorphisms of apolipoprotein-B gene to dyslipidemia and obesity in Asian Indians in North India

BACKGROUND

Genetic investigation of dyslipidemia and obesity prevalent in the Indian population form the basis of this study.

METHODS AND RESULTS

The frequency of restriction fragment length polymorphisms (Xba1 and EcoR1) of the apolipoprotein-B gene was investigated in a case-control study of 30 hyperlipidemic and 40 normolipidemic subjects. By univariate analysis, old age, higher body mass index, waist-hip ratio and sum of four skinfolds were found to be significantly associated with hyperlipidemia. The frequencies of X- and E+ alleles of the apolipoprotein-B gene were significantly higher in North Indians in the state of New Delhi (0.83 and 0.91, respectively) as compared to the observations made in Caucasians in previous studies, but was similar to the frequency reported in Indians settled in Singapore and the UK. There were no significant differences in the allele or genotype frequencies of either Xba1 or EcoR1 polymorphisms between the hyperlipidemic and normolipidemic groups. On multiple logistic regression analysis considering body mass index, waist-hip ratio, percentage body fat and genotypes as independent variables, no association was observed between the apolipoprotein-B genotypes and serum lipid components. Further, there were no associations between apolipoprotein-B polymorphisms and generalized obesity (as assessed by body mass index, sum of four skinfolds, and percentage total body fat) and abdominal obesity (as measured by waist circumference and waist-hip ratio).

CONCLUSIONS

We conclude that apolipoprotein-B (Xba1 and EcoR1) polymorphisms do not appear to influence serum lipid levels and parameters of generalized andregional obesity in the study sample.

Safe use of hepatic allografts from donors older than 70 years

Between March 1991 and August 1995, 36 livers from donors >/=70 years old were transplanted. In donors, we recorded the following risk factors: alanine aminotransferase > 120 and rising, dopamine dose > 15 microg/kg/min, hypotension (systolic blood pressure <80) >1 hr, stay in the intensive care unit >5 days and body mass index >/=27. In 35 recipients, we recorded pretransplant United Network for Organ Sharing (UNOS) status, cold/warm ischemia time, intraoperative blood loss, and occurrence of poor early graft function or primary nonfunction. Mean recipient age was 55 years (range, 25-75 years). Four recipients were UNOS status 1, 19 were UNOS 2, and 12 were UNOS 3. Two livers were used as second grafts for primary graft nonfunction. Mean donor age was 73 years (range, 70-84 years). Intracranial bleeding was the cause of death in the majority of donors. The 36 donors had 40 risk factors; 10 donors had >1 risk factor. Mean cold and warm ischemia times were 9:08 +/- 2:57 hr and 51 +/- 9 min. Mean total operative time was 7.5 hr. Posttransplant mean peak alanine aminotransferase and aspartate aminotransferase levels were 937.3 +/- 703.1 IU/L and 923.3 +/- 708.5 IU/L, respectively. Mean prothrombin time on postoperative day 2 was 14.9 +/- 1.6 sec. Average total bilirubin on postoperative day 5 was 4.9 mg/dl. Median length of stay in the intensive care unit was 4 days. One recipient had poor early graft function; two recipients had primary nonfunction. Mean follow-up was 503 days (range, 110-1714 days). Three-month actual graft and patient survival rates were 85% and 91%, respectively. One-year actuarial graft and patient survival rates were also 85% and 91%, respectively. We conclude that older livers can be used safely. Advanced donor age should not be a contraindication to liver procurement.

Urinary incontinence: prevalence, need for treatment, and effectiveness of intervention by nurse

OBJECTIVE

To measure the unmet need of patients with regular urinary incontinence (incontinence twice or more a month) treatable by a nurse.

DESIGN

Self completed postal questionnaire and randomised controlled trial of assessment and intervention by a nurse.

SETTING

One urban and one rural general practice in Somerset.

SUBJECTS

7300 adults randomly selected from 10,300 aged 35 and over on the combined practice lists. 515 women and 185 men with regular incontinence were offered assessment and treatment, of whom 134 women and 49 men had no intervention for three months (historical controls). They then joined the assessment and treatment programme.

INTERVENTION

Four sessions of pelvic floor exercises and bladder retraining supervised by non-specialist nurse who had taken a three week course on assessing and treating uncomplicated incontinence.

MAIN OUTCOME MEASURES

Number of patients desiring treatment; self reported cure, improvement, or deterioration in continence after three months.

RESULTS

The questionnaire achieved a 79% response. Validated responses showed a prevalence of 4.4% in men and 16.4% in women aged 35-64. 315 (45%) of the 700 patients offered assessment refused it and seven had moved away or died, 64 men and 41 women were referred to their general practitioner. 197 of 292 treated women (68%) reported cure or improvement compared with seven (5%) of controls. 22 of the 86 men desiring treatment were suitable for intervention by the nurse. Seventeen were cured or improved compared with none of the men in the control group.

CONCLUSIONS

About half the people with regular urinary incontinence took up the offer of treatment (9.2% of women and 3.4% of men in the study population). This condition can be effectively managed by a nurse with limited training.

Resolution of enzyme bands of Plasmodium knowlesi as a function of substrate concentration

An extra band of isoenzyme lactate dehydrogenase (LDH) was obtained in case of Plasmodium knowlesi free parasite as compared to normal monkey blood. This extra band could be resolved due to the decreasing amount of substrate concentration. Agarose electrophoresis technique was used to separate the isoenzyme bands.

Gastritis and gastric campylobacter-like organisms in patients without peptic ulcer

Gastric biopsy specimens were obtained from 83 patients without peptic ulcer disease and analysed histologically. Culture and serological studies were done on the last 64 patients. The patients were divided into two age groups (young and old groups.) In 34 patients with chronic superficial gastritis, gastric campylobacter-like organisms (GLCO) were identified histologically in 91% and grown on culture in 88%: antibody to GCLO was detected in 81%. No age-related difference in the prevalence of the organism was demonstrated. In the 23 patients with atrophic gastritis (all elderly), presence of the organisms appeared to be related to the presence of an inflammatory cell infiltrate into the gastric mucosa. These figures for the prevalence of the organism in this selected group of patients are similar to those reported in previous studies of unselected patients which included those with peptic ulcer. This suggests that GCLO is unlikely to be causally related to peptic ulcer.

Antibody to the gastric campylobacter-like organism ("Campylobacter pyloridis")--clinical correlations and distribution in the normal population

Different cellular proteins of the gastric campylobacter-like organism (GCLO) were shown to be immunogenic for man. Antibodies to GCLO were detected in sera by both complement fixation and enzyme-linked immunoabsorbent assay. Antibody was found in 133 (52%) of 254 patients attending for gastroscopy. There was a high correlation between presence of antibody and a positive GCLO culture from the gastric mucus. Patients with normal endoscopic appearances, duodenal ulcer, duodenitis and oesophagitis had similar prevalences (c. 50%) of antibody. Only patients with endoscopically visible gastritis or gastric ulcer had a higher frequency (c. 80%) of antibody. In a normal population, antibody was uncommon in individuals less than 20 years old, but the prevalence of antibody increased (to c. 50%) with age. There was little evidence to support an important pathological role for GCLO in disorders of the upper gastrointestinal tract, although the possibility that it may be a co-factor in the pathogenesis of gastric ulcer cannot be excluded.

Theiler's virus antigen detected in mouse spinal cord 2 1/2 years after infection

Spinal cord sections from mice injected with Theiler's murine encephalomyelitis virus (TMEV) and surviving for 1 year and longer after infection were stained for virus antigen by two immunohistochemical techniques. Virus antigen was detected from 1 to 2 1/2 years after infection, a time when no virus was recovered at an assay sensitivity of 50 plaque-forming units per gram of tissue. The implication this has regarding the detection of a virus in MS is discussed.

Location and distribution of virus antigen in the central nervous system of mice persistently infected with Theiler's virus

The present study has shown that virus can be readily detected by immunofluorescent staining in the central nervous system (CNS) of SJL mice persistently infected with Theiler's murine encephalomyelitis virus (TMEV). Considering the low CNS virus content, large amounts of virus antigen were found in the white matter, the site of demyelinating lesions. Virus antigen was detected in all animals killed after post-infection (PI) Day 21, a time which can be considered as the beginning of the persistent phase of this infection, and the appearance of virus antigen in white matter corresponded closely in time with the onset of demyelination. The pathogensis of this persistent infection can now be reasonably well reconstructed from the temporal observations made in this study. It would appear that between the second and third week PI, virus replication largely shifts from neurons in spinal cord gray matter to other cell types located in white matter. While a lower-grade persistent infection (in terms of the relative number of cells containing virus antigen) is established and maintained in cells in the gray matter and inflammatory and leptomeningeal infiltrates, cells in white matter appear to be mainly responsible for perpetuating the infection. Why these cells should supplant neurons as the most susceptible host cell during the chronic phase of the infection is discussed.

Characterization of Vilyuisk virus as a picornavirus

The V-1 strain of Vilyuisk virus, isolated from the cerebrospinal fluid of a chronic case of encephalomyelitis in Siberia and subsequently passaged 41 times in mice, was examined to determine its serological relationship to Theiler's murine encephalomyelitis virus (TMEV) and encephalomyocarditis (EMC) virus and some physicochemical characteristics of the virion. On the basis of virion size (28 nm), icosahedral symmetry, buoyant density (1.33 g/ml), sedimentation coefficient (150S), and capsid polypeptide profile, Vilyuisk virus appears to belong to the family Picornaviridae. Acute phase mouse antisera were used to study the antigenic relatedness of Vilyuisk, GDVII (the prototypic strain TMEV), and EMC viruses by enzyme-linked immunosorbent assay (ELISA). The results indicate that Vilyuisk and GDVII viruses are similar but distant subtypes, and that Vilyuisk and EMC viruses are unrelated.

The growth of four human and animal enteroviruses in the central nervous systems of mice

The pattern of CNS infection of our enteroviruses, Coxsackievirus A14, encephalomyocarditis (EMC) virus, GDVII virus, and Vilyuisk virus, was investigated. The regional sites of virus replication were correlated with pathological changes. These viruses were found to replicate and produce similar lesions in selected sites in the mouse CNS during acute infection. Virus antigen and histological lesions were essentially confined to the gray matter, with additional but less direct support for this being provided by virus assay of CNS regions. Virus antigen only could be confidently identified in neurons, and, histologically, neurons were observed in various stages of degeneration. The distribution of the involvement varied in the different infections. For example, EMC virus infection primarily affected the cerebral hemispheres and thalamus, while Coxsackievirus a14 infection predominantly involved the brainstem and spinal cord. GDVII and Vilyuisk virus infections more uniformly involved the entire neuraxis. There was no evidence of virus replication in the olfactory bulbs, leptomeninges, ependyma, choroid plexus, and vascular endothelium. The cerebellum was generally spared, with the cerebellar hemispheres affected only in Coxsackievirus A14 infection. It therefore appears that enteroviruses selectively infect different populations of nerve cells.