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Biomedical subjects

J M Somers

Publications and source records attributed to J M Somers.

At least 19 recordsLinked to original sources
PubMed2003

Cervical spine injuries to children under 11: should we use radiography more selectively in their initial assessment?

OBJECTIVES: To assess the effectiveness of cervical spine radiography in injured children under 11 years old, and suggest improvements. METHODS: Retrospective survey of radiographs and accident and emergency records for children examined during a one year period in a large teaching hospital. RESULTS: No cervical spine fractures occurred in this age group during the year. The recorded clinical findings did not always justify radiography. CONCLUSIONS: Clinical examination appears undervalued by those assessing injured children and is poorly recorded. Radiography can be used more selectively. Initial assessment using a single lateral projection can be followed in doubtful cases by cross sectional imaging.

Age Distribution↗
PubMed2000

The role of the plain radiograph and renal tract ultrasound in the management of children with renal tract calculi.

AIMS: The aim of this retrospective study was to assess the relative efficacy of plain abdominal radiographs and detailed renal tract ultrasound (US) examination in the diagnosis and follow-up of children with renal tract calculi. METHODS: The records and imaging studies of 28 paediatric patients who had presented with proven renal tract calculi over a period of 5 years were examined. RESULTS: In 23 (82%) patients, US was the first investigation. All these patients also had plain radiographs. Plain radiographs were the first investigation in five (18%) patients. All renal calculi (100%) visible on plain films were demonstrated on US. Furthermore, detailed US often provided other clinically significant findings that were not apparent on plain films. CONCLUSION: As a result of this study it is recommend that detailed US should be the investigation of choice in children with suspected renal tract calculi.

Adolescent↗
PubMed1998

Improved ultrasound detection of renal scarring in children following urinary tract infection.

A system for defining renal scarring on ultrasound is proposed and compared with DMSA scintigraphy. Renal scarring was assessed with ultrasound in children following urinary tract infection (UTI) using the following criteria: (1) proximity of sinus echoes to cortical surface; (2) loss of pyramids; (3) irregularity of outline; (4) loss of definition of capsular echo; and (5) calyceal dilatation. Three hundred and thirty-nine consecutive ultrasound scans (US) and DMSA scintigrams, comprising 648 kidneys, were performed and reported blindly and the results were compared. Using DMSA scintigraphy as the gold standard, ultrasound had a positive predictive value of 93% and a negative predictive value of 95%. Ultrasound disagreed with DMSA scintigraphy in 5.2% of kidneys. On review of the cases of disagreement where arbitration was possible by comparison with other imaging, ultrasound was incorrect in 10 kidneys and DMSA was incorrect in 13. We conclude that the sensitivity in the ultrasound detection of renal scarring can be greatly improved using this method. If no scars were detected at ultrasound an alternative explanation for an abnormal DMSA scintigram should be sought.

Adolescent↗
PubMed1998

Screening and brief intervention for high-risk college student drinkers: results from a 2-year follow-up assessment.

This randomized controlled trial evaluated the efficacy of a brief intervention designed to reduce the harmful consequences of heavy drinking among high-risk college students. Students screened for risk while in their senior year of high school (188 women and 160 men) were randomly assigned to receive an individualized motivational brief intervention in their freshman year of college or to a no-treatment control condition. A normative group selected from the entire screening pool provided a natural history comparison. Follow-up assessments over a 2-year period showed significant reductions in both drinking rates and harmful consequences, favoring students receiving the intervention. Although high-risk students continued to experience more alcohol problems than the natural history comparison group over the 2-year period, most showed a decline in problems over time, suggesting a developmental maturational effect.

Adolescent↗
PubMed1994

fimA and tctC based DNA diagnostics for Salmonella.

Immunochemical analyses of 85 isolates of 17 Salmonella serovars using polyclonal antiserum to SEF21, the type 1 fimbriae of Salmonella enteritidis, demonstrated antigenic relatedness among both type 1 and type 2 fimbriae of Salmonella. However, anti-SEF21 antiserum was not entirely suitable as a Salmonella diagnostic probe due either to a variability of, or a rare deficiency of, detectable fimbriae. Partial amino acid sequence analyses of the SEF21 structural fimbrin protein revealed 99% homology to Salmonella typhimurium FimA. Therefore, oligonucleotide probes for Salmonella detection were designed following sequencing of S. enteritidis fimA and comparison to the corresponding genes of S. typhimurium, Escherichia coli, Klebsiella pneumoniae and Serratia marcescens. One oligonucleotide probe hybridized to all 612 Salmonella isolates of 89 serovars tested while two other probes detected 97.5% and 99.7% of the isolates. Three consistently weak positive reactions were obtained, therefore, inclusivity was optimized by identification of a Salmonella-specific tctC DNA probe that detected 609 of 612 Salmonella isolates. No hybridization of these Salmonella probes was detected to 250 other Enterobacteriaceae isolates or to 14 other eubacterial species. Therefore, in combination, DNA probes to fimA and tctC proved to be highly reliable diagnostics for Salmonella bacteria. Accordingly, PCR assays targeting fimA and tctC were developed.

Amino Acid Sequence↗
PubMed1993

Pictorial review: benign and malignant enlargement of the pterygo-masseteric muscle complex.

Seven cases of unilateral enlargement of the pterygoid and/or masseter muscles due to haemangioma (1), benign masseteric hypertrophy (2), rhabdomyosarcoma (2), leukaemic infiltration (1) and non-Hodgkin's lymphoma (1) are presented. The differential diagnosis of pterygo-masseteric muscle enlargement is outlined and the usefulness of computed tomography (CT) discussed.

Adolescent↗
PubMed1993

Radiologically-guided cutting needle biopsy for suspected malignancy in childhood.

Twenty-seven cutting needle biopsies were performed on 25 children with suspected malignancy using computed tomographic (CT, 22) or ultrasound (US, 5) guidance. Anatomical sites were: retroperitoneum 6, liver 4, kidney 4, abdomen/pelvis 4, thorax 4, bowel 2, neck 1. Sixteen patients (64%) underwent subsequent open biopsy (5), marrow biopsy (2) or resection (9). There was complete concordance between the histological findings from the open or marrow biopsy and the previous needle biopsy in 12 of these 16 patients; in two patients the needle biopsy was misleading, causing inappropriate initial treatment in one. In two other patients needle biopsy was correct but lacked specific diagnostic features. Needle biopsies were performed under general, local or Ketamine anaesthesia. There were no apparent complications related to these procedures. We believe that radiologically-guided cutting needle biopsy should replace open biopsy in most children with solid malignant lesions. It can easily be performed during a single anaesthetic episode which allows radiological evaluation, biopsy, bone marrow and cerebrospinal fluid sampling. However, the potential for sampling error and histological variation within these tumours needs to be borne in mind.

Adolescent↗
PubMed1991

Coronary cameral fistulae following heart transplantation.

Coronary cameral fistulae in 208 orthotopic heart transplants performed at Papworth Hospital were examined. Sixteen fistulae in 208 heart transplants were identified (7.7%). This compares with a reported incidence of 0.2% or less in native hearts. Seven (3.4%) were similar to previously described fistulae to the right ventricle and were secondary to endomyocardial biopsy. Four (1.9%) arose from right or left coronary artery atrial branches and drained into the right atrium. We have called these 'suture line fistulae'. Five (2.4%) arose from left coronary branches at the apex; four of these drained into the left ventricle and one into the right ventricle. We believe these to be secondary to cutting needle biopsy of the apex of the donor heart before transplant and have designated them 'harvest biopsy fistulae'. One patient with a large fistula angiographically had no oximetric evidence of shunt at cardiac catheterization. Coronary cameral fistulae are an uncommon complication of heart transplantation and follow-up biopsy, and appear to be of no haemodynamic significance.

Biopsy, Needle↗
PubMed1990

Rupture of the right hemidiaphragm following blunt trauma: the use of ultrasound in diagnosis.

Diaphragmatic rupture occurs in approximately 5% of patients who sustain multiple trauma and post-mortem studies suggest that right-sided rupture is more common than generally realized. Four cases of rupture of the right hemidiaphragm secondary to blunt trauma are presented. The chest radiographs were all similar, demonstrating a right sided fluid collection and right lower lobe consolidation in all patients. No patient had a pneumothorax. CT was useful only in retrospect, demonstrating a posterior eventration of the liver into the thorax in two patients. Ultrasound proved diagnostic in all cases demonstrating either the free edge of the diaphragm as a flap within the pleural fluid or the liver herniating into the thorax. The value of ultrasound as a simple, non-invasive and direct means of imaging the diaphragm is emphasized.

Accidents, Traffic↗
PubMed1989

Genetic regulation of the tricarboxylate transport operon (tctI) of Salmonella typhimurium.

Tricarboxylates are transported into Salmonella typhimurium by a binding protein-dependent transport system known as TctI. Genetically, it comprises three structural genes, tctCBA, as well as a fourth gene of unknown function (tctD), which is transcribed divergently from tctC (K. A. Widenhorn, J. M. Somers, and W. W. Kay, J. Bacteriol. 170:3223-3227, 1988). Deletions in tctD strongly reduced expression of tctC or of tctC-lacZ transcriptional fusions; however, expression was restored when tctD was present in trans. Expression of tctD-lacZ transcriptional fusions was strongly repressed in the presence of D-glucose but could be alleviated by the addition of cyclic AMP. Furthermore, transcription of tctD was found not to be autogenously regulated. Thus, tctD is considered to be regulated by catabolite repression and encodes a transcriptional activator of tctCBA expression. From the DNA sequence of tctD, the predicted gene product was hydrophilic and shared distinct homologies with other globally regulated transcriptional activators such as OmpR and NtrC.

Amino Acid Sequence↗
PubMed1988

Cloning and properties of the Salmonella typhimurium tricarboxylate transport operon in Escherichia coli.

The tricarboxylate transport operon (tctI) was cloned in Escherichia coli as a 12-kilobase (kb) fragment from an EcoRI library of the Salmonella typhimurium chromosome in lambda gtWES. It was further subcloned as a 12-kb fragment into pACYC184 and as an 8-kb fragment into pBR322. By insertional mutagenesis mediated by lambda Tn5, restriction mapping, and phenotypic testing, the tctI operon was localized to a 4.5-kb region. The tctC gene which encodes a periplasmic binding protein (C protein) was located near the center of the insert. E. coli/tctI clones on either multicopy or single-copy vectors grew on the same tricarboxylates as S. typhimurium, although unusually long growth lags were observed. E. coli/tctI clones exhibited similar [14C]fluorocitrate transport kinetics to those of S. typhimurium, whereas E. coli alone was virtually impermeable to [14C]fluorocitrate. The periplasmic C proteins (C1 and C2 isoelectric forms) were produced in prodigious quantities from the cloned strains. Motile E. coli/tctI clones were not chemotactic toward citrate, whereas tctI deletion mutants of S. typhimurium were. Taken together, these observations indicate that tctI is not an operon involved in chemotaxis.

Biological Transport↗
PubMed1988

Expression of the divergent tricarboxylate transport operon (tctI) of Salmonella typhimurium.

Membrane-associated gene products of shock-sensitive bacterial transport operons are often difficult to detect. A 4.5-kilobase DNA fragment, known to completely encode the Salmonella typhimurium tctI operon, was cloned in both orientations behind the T7 phage promoter phi 10 and expressed by using the T7 polymerase-promoter system of Tabor and Richardson (S. Tabor and C. C. Richardson, Proc. Natl. Acad. Sci. USA 82:1074-1078, 1985). Under these conditions, five proteins were clearly demonstrated. One DNA strand was shown to encode the periplasmic (29,000-Mr) C protein (as a 31,000-Mr precursor), a 19,000-Mr protein, and a 40,000- to 45,000-Mr protein which ran as a diffuse band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The opposite strand carried the information for two additional proteins of 29,000 and 14,000 Mr. By Tn5 mutagenesis, subcloning of Tn5 insertions, and subcloning of various deletion mutants it was shown that the tctI system is divergently transcribed. The periplasmic binding protein (C protein) is the first product of one operon, followed by the 19,000-Mr and 45,000-Mr integral inner membrane proteins. On the opposite strand only the 29,000-Mr protein was essential for tctI function, and it was found to be weakly attached to the inner membrane. Thus tctI encodes four proteins, one periplasmic, two integral, and one peripheral to the cytoplasmic membrane, with the genes arranged as tctA tctB tctC tctD.

Biological Transport↗
PubMed1983

Genetic fine structure of the tricarboxylate transport (tct) locus of Salmonella typhimurium.

The tct (tricarboxylate transport) locus of Salmonella typhimurium is found at 59 units between nalB and pheA (Somers et al. 1981). This locus was further resolved by fine structure genetic mapping and by analysis of one of the gene products, the tricarboxylate binding protein (C protein). 135 independent fluorocitrate resistant clones were isolated and 12 point mutants were ordered by 3 point reciprocal crosses using an adjacent Tn10 insertion. Eight spontaneous deletions as well as 17 deletions arising from imprecise excisions of internal and flanking Tn10 elements were used to construct a deletion map comprising 21 deletion segments. 115 strains were than assigned to these segments to complete the fine-structure map. Using the expression of the C protein as a guide, an analysis of a variety of mutant strains indicated: that the tct locus is composed of at least four genes and transcription is clockwise; the C protein structural gene (tctC) resides in the centre of the region and codes for two isoelectric forms of the C gene product; tctC is flanked by two regions which are involved in transport but whose gene products are not yet identified.

Biological Transport, Active↗
PubMed1981

Flurorcitrate resistant tricarboxylate transport mutants of Salmonella typhimurium.

Spontaneous and Tn10 induced fluorocitrate resistant mutants were isolated and characterized. These mutants were unable to grow on either cis-aconitate or DL-isocitrate but were still able to grow slowly on sodium citrate and normally on potassium or potassium-plus-sodium citrate. These mutants were defective in both citrate transport and citrate binding to priplasmic proteins. Tn10 insertion mutants were unable to produce immunologically detectable amounts of the citrate inducible periplasmic C protein previously shown to bind tricarboxylates. Using a series of tct::Tn10 directed Hfrs the tct locus was accurately positioned at 59 units between srlA and pheA, but was not cotransducible with either gene. In the absence of P22 mediated cotransduction with 16 adjacent chromosomal markers the srlA and tct loci were bridged by using a series of tct flanking Tn10 insertions, and by newly isolated and characterized nalB mutants. In addition the hyd and recA loci were located establishing the gene order in this region of the chromosome as: pheA tct nalB recA srlA hyd cys. Nitrosoguanidine derived tricarboxylate mutations (Imai 1975) were also mapped within the tct locus.

Bacterial Proteins↗