Successful nanolitre real-time PCR detection of respiratory pathogens in clinical specimens.

We performed a proof-of-concept study to determine if human pathogens could be detected in clinical specimens using nanolitre-volume real-time PCR. Nanolitre PCR for Bordetella pertussis/B. parapertussis and respiratory syncytial virus (RSV) was performed on nasopharyngeal specimens and results compared with conventional methods. B. pertussis/B. parapertussis nanolitre PCR detection was 100% sensitive (20/20; 95% CI, 84-100%) and 100% specific (26/26; 95% CI, 87-100%). RSV nanolitre PCR was also 100% sensitive (21/21; 95% CI, 85-100%) and specific (25/25; 95%, CI 87-100%). Respiratory pathogens can be successfully detected in clinical specimens using nanolitre-volume PCR.

Pyrosequencing assay to rapidly detect clarithromycin resistance mutations in Canadian Helicobacter pylori isolates.

BACKGROUND: Mutations at positions 2142 or 2143 in the twocopy 23S ribosomal RNA gene of Helicobacter pylori are highly predictive of in vitro clarithromycin resistance and failure of clarithromycin-containing treatment regimens. OBJECTIVE: To design an assay to rapidly detect these mutations using rapid polymerase chain reaction and pyrosequencing, a novel method of 'sequencing by synthesis', and to test this assay with a collection of Canadian H pylori isolates. METHODS: Forty-two H pylori isolates (24 clarithromycin-resistant, 18 clarithromycin-susceptible) were studied. A target region in the 23S gene was rapidly amplified and sequenced by pyrosequencing. RESULTS: Mutations at one of the two positions studied were present in 20 of the 24 (83%) clarithromycin-resistant isolates; 13 had double- copy A2143G mutations, four had double-copy A2142G mutations and three had single-copy A2143G mutations. There were no mutations in 17 of the 18 (94%) susceptible isolates. A single-copy A2142G mutation was detected in one susceptible isolate. CONCLUSIONS: The pyrosequencing assay developed was able to detect and differentiate mutations at positions 2142 and 2143 in either one or both copies of the H pylori 23S ribosdomal RNA gene. Further study is needed to determine whether this pyrosequencing assay can be used to determine H pylori susceptibility to clarithromycin from clinical specimens such as stools or gastric biopsies.

Transfusion-transmitted malaria in Canada.

Three cases of transfusion-transmitted malaria in Canada are described. Although very rare, this diagnosis should be considered in transfusion recipients who have undiagnosed symptoms consistent with malaria. Thick and thin blood smears should be urgently examined to exclude this possibility.

Illness outbreak associated with Escherichia coli O157:H7 in Genoa salami. E. coli O157:H7 Working Group.

BACKGROUND: An outbreak of Escherichia coli O157:H7 infection was identified in the spring of 1998, with a 7-fold increase in the number of laboratory-confirmed E. coli O157:H7 cases in southern Ontario. This prompted an intensive investigation by local, provincial and federal public health officials. METHODS: Case interviews of 25 people from southern Ontario were conducted using a broad food history and environmental exposure survey. Laboratory investigations involved both case and food sampling. Specimens of foods sold locally and reportedly consumed by those affected were tested. Common suppliers of suspected foods were identified by cross-referencing suppliers' lists with stores frequented by those who fell ill. A case-control study involving 25 cases and 49 age-matched controls was conducted. This was followed by a comprehensive environmental investigation of the meat processing plant identified as the source of the E. coli. RESULTS: Thirty-nine outbreak-related cases occurred between April 3 and June 2, 1998. Of the 36 case specimens tested all were positive for E. coli O157:H7. The case-control study identified Genoa salami as the most probable (odds ratio 8 [confidence interval 2-35]) source of the outbreak. Samples of Genoa salami produced by the most commonly identified supplier later tested positive for E. coli O157:H7, and the pathogen matched the same pulsed-field gel electrophoresis pattern and phage type of the case specimens. INTERPRETATION: Our investigation, which led to a national recall of the brand of dry fermented Genoa salami identified as the source of the outbreak, supports an adherence to stringent manufacturing requirements for fermented meat products. A review of the Canadian standards for fermented meat processing and the effectiveness of their implementation is warranted.

Prevalence of GBV-C/hepatitis G virus viremia and anti-E2 in Canadian blood donors.

BACKGROUND AND OBJECTIVES: GB virus C (GBV-C)/hepatitis G virus (HGV) is a recently recognized parenterally and sexually transmitted agent. The prevalence of GBV-C/HGV markers in Canadian blood donors has not been previously studied and was therefore determined. MATERIALS AND METHODS: Blood donors [identity unlinked (IU), short-term temporarily deferred (STTD) and autologous groups] and donor samples with antibodies to hepatitis C (anti-HCV) or hepatitis B core were tested for GBV-C/HGV RNA and for antibodies to E2 antigen (anti-E2). RESULTS: GBV-C/HGV RNA was found in 1.1% and anti-E2 in 7.3% of the combined IU/STTD donor group. Viremia was much more common in anti-HCV-positive samples (12.5%); anti-E2 was present in >50% of this group. In the STTD group, female gender was significantly associated with viremia. CONCLUSION: GBV-C/HGV infection is relatively common in Canadian donors, and a small proportion are viremic. The association of female gender and viremia was unexpected. Further study is needed to clarify the epidemiology and natural history of GBV-C/HGV infection.

Community-acquired needle stick injuries in Canadian children: Review of Canadian Hospitals Injury Reporting and Prevention Program data from 1991 to 1996.

OBJECTIVE: To review community-acquired needle stick injuries (CANSIs) in children reported to a Canadian emergency room-based injury surveillance program. DESIGN: Analysis of 1991 to 1996 CANSI records followed by chart review to determine use of prophylactic interventions and outcome information. SETTING: The Canadian Hospitals Injury Reporting and Prevention Program network of 10 paediatric and six general hospitals. PATIENTS: Nonoccupational injuries to patients younger than age 20 years involving used needles were reviewed. MAIN RESULTS: Of 116 children injured, most were male (74%); the median age was 6.6 years. Needles were picked up before injury in 77% of the cases. Most injuries (78%) were from needles presumed to have been discarded by an injection drug user. Parks were the most common site of injury (21%). Six per cent of injuries occurred in medical settings. Treatment information was obtained for 71 (61%) patients. Only 1.7% had been immunized against hepatitis B virus before injury. Hepatitis B immune globulin and hepatitis B virus vaccine were given to 78% and 76% of children, respectively. None received human immunodeficiency virus prophylaxis. CONCLUSIONS: Programs teaching needle avoidance may help prevent many CANSIs. The safety of outdoor, home and medical environments also needs to be ensured. Treatment guidelines for CANSIs will help ensure appropriate postinjury management.

Late strut fracture of the Beall model 105 disc valve prosthesis.

Strut fracture, with embolization of the disc occluder, caused the death of a 64-year-old man who had a Beall model 105 heart valve prosthesis in the mitral position for 13 years. Scanning electron microscopy of the fractured surface revealed evidence of a fatigue failure mechanism in the metal wire. The case is unique in that strut fractures affecting this prosthesis had only been observed previously in the range of 141 to 342 days after implantation. Morphological changes in this valve prompted reexamination of three other model 105 prostheses that had been recovered from the mitral area at necropsy or surgery 9 to 10 years after insertion in 1972 or 1973. All had been kept in dry storage. The three prostheses and the valve described above showed previously unrecognized cracks in the pyrolytic carbon coating of the struts, which form the cage that limits occluder movement. The defects were located at or near the base of struts, where they entered the sewing ring and were bent to pass into the strut supporting ring. We believe that the cracks in the carbon coating precede total strut fracture and postulate that they are needed for the metal wire to be subject to a fatigue failure mechanism.

IgA nephropathy in relapsing polychondritis.

Relapsing polychondritis (RP) is a multisystem autoimmune disease characterized by the presence of antibodies to type II collagen. This collagen is found predominantly in cartilaginous tissues, vitreous humor, aorta and notochord. Involvement of the kidney is rare, only 7 cases having been recorded, and there is no type II collagen in glomeruli. Six of the previous cases had crescentic glomerulonephritis. We report here two cases of biopsy proven RP in which IgA nephropathy was seen, the first examples recorded. Both patients had hematuria and slight proteinuria, with mild impairment of renal function. The histological and immunofluorescence pattern on both biopsies was in keeping with IgA nephropathy. Both patients received steroids with diminution/disappearance of hematuria and proteinuria. In view of the potentially progressive nature of glomerular disease with RP, the renal status should be investigated in all patients with RP.

Erosive parapharyngeal space teratoma.

An erosive teratoma of the parapharyngeal space is described. Our patient at three months of age presented with an eight-week history of torticollis. Diagnosis was strongly suggested by CT scan which clearly demonstrated bony, fluid and intermediate densities suggestive of a teratoma. The tumor had eroded the petrous bone with inferior extension to the level of the hyoid cartilage. An angiogram revealed compromise of the internal carotid artery at the skull base. Surgical resection at five months removed the tumor from the right parapharyngeal space and included a portion of the petrous bone involving the contents of the middle ear and extending to the base of skull. All vital structures including the facial nerve, carotid artery and vagus nerve preserved. An intraoperative CSF leak was controlled with a muscle plug. To our knowledge, such an extensive teratoma eroding the petrous bone and base of skull, presenting as a neck mass, is the first reported case in the literature. The value of a CT scan as an aid in diagnosis of this tumor is stressed.

Renal and systemic kappa light chain deposits and their plasma cell origin identified by immunoelectron microscopy.

Kappa light chain determinants were identified by immunoelectron microscopy in nodular glomerulosclerotic lesions and systemic interstitial deposits from a man who died several years after the onset of proteinuric renal failure treated by hemodialysis. He developed adrenal and hepatic failure preterminally but not overt malignant myeloma. Specific labeling was most concentrated over the inner aspect of glomerular basement membrane and the mesangium, which suggested that the protein was nonfiltrable. Tubular basement membrane labeling was densest over the outer aspect, which suggested that the protein perfused from the interstitium rather than from the tubular lumen. We identified the source of the protein as a population of plasma cells present within bone marrow and renal interstitium; these showed specific immunogold labeling for kappa light chain protein over organelles concerned with protein synthesis, secretion, and storage. This appears to be the first identification of light chain determinants in human interstitial para-amyloid deposits with the use of immunogold ultrastructural techniques in tissues prepared for electron microscopy by standard methods and stored as epoxy resin blocks.

Formaldehyde-induced fluorescence in melanomas and other lesions. Diagnostic significance and mechanism of fluorescence.

We have investigated 40 cases of malignant melanoma (MM) and 81 other lesions including benign melanocytic neoplasms, other malignancies with a potential for confusion with MM, and tissues with biogenic amine-synthesizing apparatus for induction of formaldehyde-induced fluorescence (FIF). Unstained sections were examined with an ultraviolet light source for yellowish fluorescence. Twenty-four of 27 primary cutaneous MMs and 11 of 13 metastatic MMs were positive. Formaldehyde-induced fluorescence was quenched by prior sodium borohydride treatment, suggesting monoamine origin. None of the ten intradermal, five junctional, or three blue nevi showed FIF, but two of eight compound nevi and two of six spindle cell nevi were positive for FIF. One of six large-cell undifferentiated carcinomas was positive; none of six mesenchymal sarcomas were positive; one of seven histiocytic lymphomas showed weak, granular, cytoplasmic fluorescence. Two of five carcinoid tumors and one case of medullary carcinoma of thyroid showed FIF. We conclude that FIF is a simple, reproducible, technique for aiding in the diagnosis of amelanotic melanomas.

Malignant schwannoma in the head and neck.

The authors' experience in dealing with three cases of malignant Schwannoma in the head and neck is outlined. The symptomatology of this tumor is discussed with its investigation and management. A correct diagnosis with a CT scan to delineate tumor extent is imperative. A wide surgical resection is the preferred method of treatment with postoperative irradiation of value for residual microscopic disease. The pernicious nature of this tumor often leads to a dismal outcome despite aggressive therapy.

Epithelial-myoepithelial carcinoma of salivary glands.

Four cases of epithelial-myoepithelial carcinoma of salivary gland origin are presented and discussed. The mean age of these four patients was 68 years, with an age range of 51 to 78 years. Three of the patients were women, and one was a man. This article emphasizes the light microscopic, histochemical, and ultrastructural features of the neoplasm. Electron microscopic examination of glutaraldehyde-fixed fresh tissue and previously formalin-fixed tissue reveals that the characteristic clear cytoplasm of abluminal cells is caused, in part, by glycogen storage granules and the paucity of organelles but largely by an artifact of fixation.

Verrucous carcinoma--changing concepts in management.

Verrucous carcinoma is an unusual, non-metastasizing, distinct variant of a well differentiated squamous cell carcinoma. Multiple biopsies are frequently necessary to establish its diagnosis. Seven of 10 patients treated with irradiation showed no evidence of anaplastic transformation. A high recurrence rate in tumors of the oral cavity treated with either irradiation or surgery alone is noted. Extensive lesions in this area may benefit from combined therapy. A good response to radiotherapy with a low recurrence rate in small laryngeal lesions is recognized. Irradiation should be considered in the management of this tumor without undue concern for change in its biologic behavior.