Improved technique for fluorescence in situ hybridisation analysis of isolated nuclei from archival, B5 or formalin fixed, paraffin wax embedded tissue

Fluorescence in situ hybridisation (FISH) is an effective method to detect chromosomal alterations in a variety of tissue types, including archived paraffin wax embedded specimens fixed in B5 or formalin. However, precipitating fixatives such as B5 have been known to produce unsatisfactory results in comparison with formalin when used for FISH. This study describes an effective nuclear isolation and FISH procedure for B5 and formalin fixed tissue, optimising the nuclear isolation step and nuclei pretreatments using tonsil and mantle cell lymphoma specimens. The protocol presented can be used to isolate nuclei and perform FISH on B5 or formalin fixed, paraffin wax embedded samples from a variety of tissue types.

Systematic review and meta-analysis of the literature regarding the diagnosis of sleep apnea

To establish the evidence base for the diagnosis of sleep apnea (SA) in adult patients, a systematic review of the literature from 1980 through November 1, 1997 was performed. Diagnostic studies were included if they reported results of any test to establish or support a diagnosis of SA, in comparison to a diagnosis from a full polysomnogram (PSG). Test results were meta-analyzed using fixed effects models and summary receiver operating characteristic curves (ROCs) to examine consistency of tests within and between diagnostics vs. the "gold standard" of PSG. From a total of 937 studies, 249 fit the broad eligibility criteria for inclusion in the clinical trial database and its data were extracted from these reports; useable data for statistical analyses were reported in 71 studies (7,572 patients). The sensitivity and specificity of partial channel and partial time PSGs appeared most promising as replacements for full PSG in patients suspected of obstructive SA. Clinical prediction rules (multivariate models) were also promising. Studies of portable sleep monitors, radiologic or morphologic features, and focused questionnaires were too heterogeneous to be meta-analyzed. In general, the diversity of study designs and objectives were very high and the methodological rigor of these studies as assessments of diagnostic tests was very low. Thus, we are still not in a position to recommend standardization of diagnostic methodology for sleep apnea. Instead, our recommendations for future research include standardization of terms and diagnostic criteria, and consistently reported statistics to enhance the utility of this literature.

Expansion of the European Race of Gremmeniella abietina in Newfoundland, Canada

Since its detection on ornamental pines in St. John's, Newfoundland, Canada, in 1979 (3), the European race causing Scleroderris canker (Gremmeniella abietina (Lagerb.) Morelet) has been detected throughout the Avalon Peninsula at the eastern end of the province. A quarantine was established on the Avalon Peninsula in 1980 to reduce the risk of introducing the disease to the natural red pine (Pinus resinosa Aiton) stands on the remainder of the island. Scots, red, and jack pines were examined at 34 locations in Newfoundland in 1998 and 1999. Infected trees were detected at four locations outside the quarantine zone. In the fall of 1998, the disease was found in plantations at three locations outside the quarantine zone: on Scots pine (P. sylvestris L.) at Bonavista and Catalina (≈135 km north-northeast of the quarantine) and on jack pine (P. banksiana Lamb.) and Scots pine at Sunnyside on Trinity Bay (≈45 km northwest of the quarantine). In 1999, the disease was detected at a fourth location on planted Scots pine in Come By Chance, near the Sunnyside location. Cultures of the pathogen were recovered from branch samples collected at each location and submitted for race determination at the Laurentian Forestry Centre, Sainte-Foy, QB. All isolates were determined based on the polymerase chain reaction diagnostic technique (1) to be the European race of G. abietina. This is a significant range extension from that reported by Laflamme et al. (2). The infected trees originated from the former Back River tree nursery at Salmonier Line that provided planting stock for a provincial reforestation program between 1937 and 1952. Evidence suggests that this nursery was the source of infected stock for plantations at nine locations within the Avalon Peninsula quarantine zone and the four new locations detected during the 1998 and 1999 surveys. This is similar to the pattern described for other nurseries in eastern Canada and the United States (2). The presence of the European race of G. abietina outside of the Avalon Peninsula increases the risk that the disease will become established in the rare natural red pine stands on the rest of the island of Newfoundland. References: (1) R. C. Hamelin et al. Appl. Environ. Microbiol. 59:1752, 1993. (2) G. Laflamme et al. For. Chron. 74:561, 1998. (3) P. Singh et al. Plant Dis. 64:1117, 1980.

First Report of Butternut Canker Caused by Sirococcus clavigignenti-juglandacearum in New Brunswick, Canada

In June 1997, butternut canker was found for the first time in New Brunswick, Canada, at Stickney, Carleton County. A fungal isolate recovered from a young branch canker on butternut (Juglans cinerea L.), cultured on potato dextrose agar, produced spores and cultural morphology as previously described (1). This strain was retained as FSC-758 in the Fredericton Stock Culture Collection at the Atlantic Forestry Centre. The disease was also detected at four other locations in Carleton County along the Saint John River watershed within 20 km of the State of Maine. One stem canker examined at Peel, Carleton County, suggests the disease has been present at this site in New Brunswick for at least 7 years. The butternut tree is at the northeastern edge of its natural range in New Brunswick and, prior to the pathogen's detection, was believed to be far enough from infected butternut in the northeastern United States, Ontario, and Quebec to escape infection. Because planted specimens of butternut exist outside the tree's natural range in New Brunswick and in the neighboring provinces of Nova Scotia and Prince Edward Island, efforts are underway to determine how far the fungus has spread in the Maritime Provinces. Reference: (1) V. M. G. Nair et al. Mycologia 71:641, 1979.

Partial tetrasomy with triplication of chromosome (5) (p14-p15.33) in a patient with severe multiple congenital anomalies

We report on a newborn infant with a de novo triplication of the distal segment of 5p: 46,XX,trp(5) (pter-->p14::p14-->p15.33::p15.33--> qter) and multiple congenital anomalies consistent with triplication of 5p. Partial triplication was documented by fluorescence in situ hybridization with a cosmid probe specific for 5p15.2 and microdissected probes obtained from "5pter." Partial duplication of the short arm of chromosome 5 is associated with a specific phenotype that appears to be dependent on the chromosomal region duplicated. Duplication of 5p with breakpoints proximal to band p14 is generally associated with distinct craniofacial malformations, cardiac, renal, intestinal, and limb defects, and mental retardation, whereas duplications with breakpoints distal to 5p14 result in a milder phenotype characterized by minor facial anomalies, developmental delay, and seizures. The most proximal breakpoints of the partial triplication in this patient was estimated to be 5p14, suggesting that a more severe phenotype can occur with triplication of the more distal segment.

Interphase cytogenetic analysis of single cell suspensions prepared from previously formalin-fixed and paraffin-embedded tissues

Fluorescence in situ hybridization (FISH) provides a rapid and accurate method for the detection of chromosomal aneuploidy. We have developed a technique for the use of FISH on single cell suspensions produced from either formalin-fixed or paraffin-embedded tissues. Preparation of such tissues involves sequential rehydration, enzymatic digestion to release single nuclei, and hybridization with a fluorescently labeled chromosome-specific centromeric probe. In a clinical setting formalin-fixed tissue from many tissue types is readily available for additional retrospective study. FISH on formalin-fixed tissues is especially beneficial in follow-up studies of cases involving termination after prenatal diagnosis or patients with a malignant disease where previous routine cytogenetics established the chromosomal aneuploidy. The use of this technique eliminates the biases of cytogenetic analysis due to clonal selection in tissue culture, the low number of cells analyzed, and the restriction to only dividing cell populations. We have demonstrated that this application of interphase cytogenetics to the study of various formalin-fixed tissues is amenable to the detection of chromosomal aneuploidies and has specific advantages over cytogenetic analysis.

Molecular cytogenetic analysis of monosomy 7 in pediatric patients with myelodysplastic syndrome

Monosomy 7 is a non-random cytogenetic abnormality that is frequently associated with myelodysplastic syndromes (MDS). Twenty-four bone marrow samples from five pediatric patients with MDS were analysed using both traditional and interphase cytogenetic analysis. The majority of the metaphases were monosomic for chromosome 7 while interphase cytogenetic analysis consistently detected a disomic cell population in nondividing cell populations. This suggests that the monosomy 7 cells have a distinct proliferative advantage compared to the disomic cell population. The results demonstrate that interphase cytogenetic analysis provides important cytogenetic information about non-dividing cell subpopulations, enhancing our understanding of the cell dynamics of normal and monosomy 7 cells in MDS.

Duplication of 9P and hyperplasia of the choroid plexus: a pathologic, radiologic, and molecular cytogenetics study

Duplication of the short arm of chromosome 9 is a rare constitutional abnormality, and the presence of pathologically confirmed hyperplasia of the choroid plexus in one of two cases, and a choroid plexus papilloma in another, raises the possibility of a relationship between the 9p abnormality and abnormal growth of the choroid plexus. Molecular cytogenetic analysis using fluorescence in situ hybridization was used for detection of chromosome 9-derived material in various formalin-fixed choroid plexus abnormalities. Extra copies of chromosome 9-derived material was found in the hyperplastic choroid plexus and in a choroid plexus carcinoma. These findings suggest that there may be an association between duplication of chromosome 9 material and abnormal development of the choroid plexus.

Astrocytoma with a unique telomere association

Many primary pediatric brain tumors are characterized by nonrandom cytogenetic abnormalities involving specific structural rearrangements and loss or gain of specific chromosomes. We describe a low-grade cerebellar astrocytoma with telomeric association of chromosomes 18 and 21 in a 7-year old girl. The nonrandom telomeric association of these chromosomes represents a unique cytogenetic finding in this type of pediatric brain tumor.

The utilization of interphase cytogenetic analysis for the detection of mosaicism

This study describes a method for defining mosaic aneuploidy by interphase cytogenetics based on statistical limits established from control specimens. Fluorescence in situ hybridization (FISH) has been used to detect the number of copies of specific chromosomes in interphase nuclei from placental tissues of diploid controls and mosaic placentas. FISH was performed using probes D7Z1/D7Z2, D9Z1, D10Z1, and D18Z1, all purchased from Oncor, Inc. Statistical analysis of data obtained from diploid controls was used to determine the one-sided upper reference limit and corresponding 95% confidence interval for the proportion of cells with one and three signals for each of the probes used. The one-sided upper reference limits established the lower levels of monosomy and trisomy detectable using each of the four probes. These statistical parameters were then used to interpret the results obtained by FISH applied to the study of term placentas for the confirmation of prenatally diagnosed chromosomal mosaicism.

Detection of confined placental mosaicism in trisomy 18 conceptions using interphase cytogenetic analysis

Fluorescence in situ hybridization provides a rapid and accurate technique for detecting chromosomal aneuploidy. It is an excellent method for identifying mosaicism in placental tissues following prenatal diagnosis. Mosaicism, in the form of confined placental mosaicism, occurs im approximately 1%-2% of viable pregnancies studied by chorionic villus sampling at 9-11 weeks of gestation. It has been detected in pregnancies with both diploid and trisomic fetuses and appears to have an important effect on the intrauterine fetal survival. Using both standard cytogenetic analysis and fluorescence in situ hybridization, we have studied 12 placentas from pregnancies with trisomy 18 for the presence of chromosomal mosaicism. These included 2 that were spontaneously aborted, 5 that were terminated after prenatal diagnosis, and 4 that were delivered as either stillborn or liveborn. Significant levels of mosaicism, confined exclusively to cytotrophoblast, were detected in 7 pregnancies. This study demonstrates the usefulness of interphase cytogenetic analysis of uncultured tissues as an alternative method for the detection of mosaicism.

Causes of pneumonia presenting to a district general hospital

The incidence of bacterial, viral, mycoplasma, and rickettsial infections has been assessed prospectively in 210 adult patients with pneumonia who presented to a district hospital over a six-year period. One hundred and thirteen infective agents were detected in 103 patients. The agent most frequently detected was Mycoplasma pneumoniae which accounted for 30 infections. A bacterial pathogen was found in 43 patients. Streptococcus pneumoniae was the most common of these (24 patients); Staphylococcus aureus (eight), Haemophilus influenzae (four), Klebsiella spp (three), and Legionella pneumophila (three) were all less common. Chlamydial or rickettsial infections (Psittacosis or Q fever) were detected in nine patients. Viral infections were found in 31 patients (22 influenza A, four influenza B, two parainfluenza, and three respiratory syncytial virus). There were 10 patients in whom more than one pathogen was identified. In 107 patients no pathogens could be identified. Seventy-five per cent of these patients had either received antibiotics before entering hospital, or were unable to produce any sputum for culture. The incidence of bacterial pneumonia has probably therefore been underestimated. Nevertheless this survey does emphasise the importance of M pneumoniae as a pathogen in patients with pneumonia presenting to hospital.