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Biomedical subjects

C McDowell

Publications and source records attributed to C McDowell.

12 recordsLinked to original sources
PubMed1997

Detection of Bordetella pertussis in clinical specimens by PCR and a microtiter plate-based DNA hybridization assay.

In order to improve detection of Bordetella pertussis in nasopharyngeal aspirates (NPAs) in our laboratory, a PCR-based assay was optimized, and a study was designed (i) to compare results obtained by PCR to those obtained by culture and (ii) to evaluate a novel microtiter plate-based DNA hybridization assay (PCR-plate) by comparing it to agarose gel electrophoresis (PCR-gel) for detection of the PCR product. DNA for the PCR was extracted with a guanidine thiocyanate buffer and used in a PCR mixture containing primers directed against a reiterated gene sequence in B. pertussis (Q. He, J. Mertsola, H. Soini, M. Skurnik, O. Ruuskanen, and M. K. Viljanen, J. Clin, Microbiol. 31:642-645, 1993). Of 96 NPAs submitted from a targeted study group, 23 were positive by culture, 27 were positive by PCR-gel, and 31 were positive by PCR-plate. All culture-positive specimens were also positive by PCR. Of nine patients with culture-negative-PCR-positive results, six had discharge diagnoses of pertussis. Thus, PCR with plate-based product detection is a sensitive method for the laboratory detection of B. pertussis in NPAs. Additional advantages of the plate assay include rapidity, objectivity in reading results, specificity, and the capability of being adapted to a high-volume, automated system.

Bordetella pertussis↗
PubMed1996

Standardizing procedures for calculating rorschach interrater reliability: conceptual and empirical foundations.

Although the Rorschach test has demonstrated significant refinements in reliability, validity, and statistical power as a result of the procedural standardization and scoring innovations introduced by Exner's Comprehensive System, the issue of Rorschach interrater reliability remains unexplored. This article examines the psychometric foundations of Rorschach interrater reliability and applies notions from applied behavioral analysis to the treatment of Rorschach data. We empirically compare 3 methods of quantifying interrater agreement, their accuracy in estimating interrater agreement, and efficiency in reducing error in Rorschach research. Results indicate that the magnitude of differences between methods of quantifying interrater agreement and the associated reductions of error are significant. We propose a standard method for quantifying interrater agreement in Rorschach research.

Adolescent↗
PubMed1994

Identification of a gene from Xp21 with similarity to the tctex-1 gene of the murine t complex.

Long range physical mapping within the p21 region of the X chromosome identified a CpG rich island approximately 180 kb centromeric to the chronic granulomatous disease (CGD) locus. The segments adjacent to the CpG island hybridized to discrete bands in DNAs of several species and when used to screen retinal cDNA libraries led to the identification of cDNAs that detected a mRNA of 2.1 kb in many tissues. Molecular characterization of corresponding genomic clones of this novel human gene confirmed the origin of the cDNA clones and indicated a genomic structure with five exons spanning a total of 9 kb. The complete cDNA sequence revealed that this gene contained a putative open reading frame of 116 amino acids with a 3' untranslated region of 1.74 kb. The amino acid sequence shows a high degree of similarity to the predicted product of the tctex-1 gene of the mouse t complex. As linkage studies and patients with deletions have implicated the Xp21 region as containing the retinitis pigmentosa defect (RP3), the gene was assessed as a candidate disease gene in RP3 families. A single base pair polymorphism was identified within the coding region but no disease associated changes were found by single strand conformational polymorphism and sequencing analysis of amplified exons of 20 RP patients. Analysis of a dinucleotide repeat polymorphism within this gene in families affected with RP3 suggested refinement of the RP3 region.

Amino Acid Sequence↗
PubMed1993

Intensive care in an Irish district general hospital--a three year review.

The International Missionary Training Hospital is a 340-bed acute general hospital with maternity and paediatric units. It serves a population of 120,000 people within the North Eastern Health Board Area and has approximately 14,000 admissions each year. This report retrospectively reviews the activity of a three bedded, Intensive Therapy Unit (ITU) over the three year period July 1987-June 1990. 805 patients (1.9% of hospital admissions) with an average age of 55 +/- 22 years (mean +/- SD, range 14-94 years) were admitted to the unit. There were 458 males (57%) and 347 females (43%). 68% of the patients were admitted from the general wards and the remainder from the accident unit. 59% of the admissions were immediate postoperative cases. 82% of patients had APACHE scores less than 20. There was a wide diversity of medical and surgical diagnoses requiring treatment. 219 cases required one or more systems to be supported and 586 (73%) were admitted as high dependency cases. For those requiring ventilation, the average ventilation time was 3.2 days (range 0.5-23 days). The average length of stay within in the unit was 2.3 days (range 1-23 days). 86% of the patients were discharged to the wards, 11% died and 3% were transferred to external specialist care facilities. ITU's in district general hospitals serve as both critical care areas and high dependency units. In our opinion they produce a positive contribution to progressive patient care for high risk medical and surgical patients.

Adolescent↗
PubMed1991

Physical mapping at a potential X-linked retinitis pigmentosa locus (RP3) by pulsed-field gel electrophoresis.

A genetic locus (RP3) for X-linked retinitis pigmentosa (XLRP) has been assigned to Xp21 by genetic linkage studies and has been supported by two Xp21 male deletion patients with XLRP. RP3 appears to be the most centromeric of several positioned loci, including chronic granulomatous disease (CGD), McLeod phenotype (XK), and Duchenne muscular dystrophy (DMD). In one patient, BB, the X-chromosome deletion includes RP3 and extends to within the DMD locus. Using a DMD cDNA, the centromeric endpoint of this patient was cloned and used as a starting point for chromosome walking along a normal X chromosome. A single-copy probe, XH1.4, positioned near the centromeric junction but deleted in BB, was used along with a CGD cDNA probe to establish a refined long-range physical map. Both probes recognized a common SfiI fragment of 205 kb. As the CGD gene covers approximately 30-60 kb, the RP3 locus has been restricted to approximately 150-170 kb. A CpG island, potentially marking a new gene, was identified within the SfiI fragment at a position approximately 35 kb from the deletion endpoint in BB.

Centromere↗
PubMed1991

Linkage analysis in X-linked ocular albinism.

We studied the linkage of X-linked Nettleship-Falls ocular albinism (OA1) to Xp22.1-Xp22.3 RFLPs at 12 loci in five families, including one in which OA1 cosegregates with a deletion of steroid sulfatase (STS). We found evidence for tight linkage of OA1 to the Xp22.3 loci DXS143, STS, and DXS452. DXS452, a newly described polymorphism detected by the probe E25B1.8, is part of the sequence family "DXS278" (pCRI-S232), but represents a single genetic locus. Every female in this study was heterozygous for the DXS452 RFLP. Thus, this marker will be extremely useful for family studies and genetic counseling. Analysis of individual recombinations suggests that OA1 maps between DXS143 and DXS85. Multipoint linkage analysis was consistent with this localization but was not statistically significant. These data suggest that OA1 lies proximal to the deletion in a previously described family with OA1 and STS deletion, but maps within the Xp22.3-Xp22.2 region.

Albinism, Ocular↗
PubMed1990

Cytochrome c-553 is not required for photosynthetic activity in the cyanobacterium Synechococcus.

In cyanobacteria, the water-soluble cytochrome c-553 functions as a mobile carrier of electrons between the membrane-bound cytochrome b6-f complex and P-700 reaction centers of Photosystem I. The structural gene for cytochrome c-553 (designated cytA) of the cyanobacterium Synechococcus sp. PCC 7942 was cloned, and the deduced amino acid sequence was shown to be similar to known cyanobacterial cytochrome c-553 proteins. A deletion mutant was constructed that had no detectable cytochrome c-553 based on spectral analyses and tetramethylbenzidine-hydrogen peroxide staining of proteins resolved by polyacrylamide gel electrophoresis. The mutant strain was not impaired in overall photosynthetic activity. However, this mutant exhibited a decreased efficiency of cytochrome f oxidation. These results indicate that cytochrome c-553 is not an absolute requirement for reducing Photosystem I reaction centers in Synechococcus sp. PCC 7942.

Amino Acid Sequence↗
PubMed1984

The treatment of the cubital tunnel syndrome.

Treatment by in situ release, submuscular transposition, and anterior subcutaneous transposition have all been reported to produce satisfactory results for ulnar neuropathy secondary to the cubital tunnel syndrome. A prospective study was done to determine which preoperative clinical and electrical factors and surgical approaches in patients with ulnar nerve palsy at the elbow had the best results. The 32 patients had an average age of 50 years, had symptoms for an average of 15 months before surgery, and underwent postoperative follow-up for an average of 13 months. All patients with good results had no atrophy or preoperative fibrillations in the intrinsic muscles and had an obtainable evoked sensory potential. The change in motor conduction velocity did not correlate with good results. There was no significant difference in the results of the three surgical procedures. Eight of the 37 operations yielded good results, 19 patients showed an improvement, but 10 of the operations yielded poor results. Our results also indicated that surgical results could be predicted by proper patient selection through the assessment of the preoperative physical examination and electromyogram.

Adult↗