First Report of Tobacco ringspot virus in Table Grapes in Michigan.

In 1998, several 10-year-old 'Marquis' and 'Vanessa' (Vitis sp.) table grapevines at the Southwest Michigan Research and Extension Center in Benton Harbor started showing decline symptoms such as stunted shoots with small leaves and berries. Vines eventually stopped producing fruit and died. In 1999, symptomatic vines were indexed on cucumber (Cucumis sativus L. 'National Pickling') cotyledons, which developed chlorotic local lesions. Symptomatic cucumber tissue was tested using Ouchterlony double diffusion with polyclonal antibodies for Tomato ringspot virus (ToRSV) and Tobacco ringspot virus (TRSV) provided by D. Ramsdell. Samples tested positive for TRSV. 'Marquis' vines (9 of 45) in the affected area also tested positive in double-antibody sandwich enzyme-linked immunosorbent assay with polyclonal antibodies for TRSV (Agdia, Inc., Elkhart, IN). Analysis of soil samples from the site in 1989 yielded five dagger nematodes (Xiphinema americanum Cobb) per g of soil, confirming the potential for virus spread by nematodes (1). TRSV reportedly infects Vitis vinifera L. but not V. labrusca L. (1). 'Marquis' and 'Vanessa' have V. vinifera heritage. The detection of TRSV has led to the establishment of a program for the production of virus-tested table grape planting stock, as well as research on the utility of nematode-resistant rootstocks for growing table grapes at the infested site. Reference: (1) R. C. Pearson and A. C. Goheen, eds. Compendium of Grape Diseases, The American Phytopathological Society, St. Paul, MN, 1995.

Cloning, sequencing, and promoter identification of Blueberry red ringspot virus, a member of the family Caulimoviridae with similarities to the "Soybean chlorotic mottle-like" genus.

The double-stranded DNA genome of Blueberry red ringspot virus (BRRV), a member of the family Caulimoviridae, was cloned and sequenced. The genome organization and relationships of the 8303 nt sequence revealed BRRV to be a tentative member of the genus that has been provisionally named "Soybean chlorotic mottle-like viruses", rather than a member of the genus Caulimovirus, in which it had been placed previously. Insertion of the putative 35S promoter homolog of BRRV into promoterless constructs carrying the UidA (beta-glucuronidase) gene resulted in high-level transient expression from cranberry and stable expression from transgenic tobacco. Sequences of 5'-RACE clones derived from transcripts from transgenic tobacco were consistent with the map position of the promoter.

Obstetrics in general practice. A rural perspective.

Obstetrics is one of the most demanding yet rewarding disciplines required of rural general practice although rising medical indemnity fees combined with medico-legal interest in this discipline make the current rural generalist obstetricians a threatened species. These factors, plus the difficulty generalist registrars have in obtaining good procedural training in this specialist field make obstetric practice less than attractive for future rural general practitioners. This article provides a brief overview of rural obstetric practice from the perspective of a rural generalist obstetrician with 18 years experience. Case studies are used to highlight the challenges of this field.

Declaring pediatric brain death: current practice in a Canadian pediatric critical care unit.

OBJECTIVE: To document the criteria used to declare brain death in a pediatric critical care unit (PCCU). DESIGN: Retrospective chart review. SETTING: Regional PCCU in southwestern Ontario. PATIENTS: Sixty patients 16 years of age or less declared brain dead from January 1987 through December 1992. OUTCOME MEASURES: Presence or absence of documentation of irreversible deep coma, nonresponsive cranial nerves, absent brain-stem reflexes, persistent apnea after removal from ventilator, presence or absence of blood flow detected by radioisotope scanning, presence or absence of electroencephalographic evidence of electrocerebral activity. RESULTS: The 60 patients accounted for 1.5% of all PCCU admissions; 17 were under 1 year of age. In 39 cases brain death was diagnosed using clinical criteria ("certified brain death"), which could not be fully applied in the remaining 21 cases ("uncertifiable but suspected brain death"). Electroencephalography and cerebral blood-flow studies with technetium-99m hexamethyl-propyleneamine oxime were used as ancillary tests in 16 patients with certified brain death and in 17 with uncertifiable but suspected brain death who survived long enough to be tested. Electrocerebral silence was demonstrated in all nine patients who underwent electroencephalography. Cerebral blood flow was undetectable in 26 of the 30 patients tested, and an abnormal pattern of blood flow was seen in the remaining 4, all of whom received a diagnosis of certified brain death. CONCLUSIONS: Pediatricians in this large tertiary care referral centre are using clinical criteria based on the 1987 guidelines of the CMA to diagnose brain death in pediatric patients, including neonates. When clinical criteria cannot be fully applied, ancillary methods of investigation are consistently used. Although the soundness of this pattern of practice is established for adults and older children, its applicability to neonates and infants still needs to be validated.

Neuropathology of heart transplantation.

The neuropathology of 18 cardiac transplant recipients was reviewed with the clinical findings. Pathological changes were noted in the central nervous system (CNS) in 94% of the patients, the most frequent being cerebral vascular in origin (72%). Eight patients (44%) had multiple cerebral infarcts and morphologically, a large number of these antedated the transplantation. In addition 4 patients had acute focal ischemic changes which occurred after transplantation. Intracranial hemorrhage was noted in 5 patients (28%), including one case of fatal intracerebral hemorrhage following an acute hypertensive episode after the transplantation. While systemic infection was common (10 patients), there were only 5 cases of intracranial infection; including 3 cases of cytomegalovirus infection, one of candidiasis and one of aspergillosis. Post-transplant seizures, occurring in a third of the patients, were related to a variety of causative factors such as sepsis, intracranial hemorrhage, cerebral ischemia, metabolic encephalopathy and cyclosporin neurotoxicity. Of note in this series was the absence of CNS lymphoma or other systemic lymphoproliferative disorder.