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Biomedical subjects

C Jones

Publications and source records attributed to C Jones.

At least 487 records · Page 27Linked to original sources
PubMed1990

A panel of irradiation-reduced hybrids selectively retaining human chromosome 11p13: their structure and use to purify the WAGR gene complex.

The irradiation-fusion technique offers a means to isolate intact subchromosomal fragments of one mammalian species in the genetic background of another. Irradiation-reduced somatic cell hybrids can be used to construct detailed genetic and physical maps of individual chromosome bands and to systematically clone genes responsible for hereditary diseases on the basis of their chromosomal position. To assess this strategy, we constructed a panel of hybrids that selectively retain the portion of human chromosome band 11p13 that includes genes responsible for Wilms tumor, aniridia, genitourinary anomalies, and mental retardation (constituting the WAGR syndrome). A hamster-human hybrid containing the short arm of chromosome 11 as its only human DNA (J1-11) was gamma-irradiated and fused to a Chinese hamster cell line (CHO-K1). We selected secondary hybrid clones that express MIC1 but not MER2, cell-surface antigens encoded by bands 11p13 and 11p15, respectively. These clones were characterized cytogenetically by in situ hybridization with human repetitive DNA and were tested for their retention of 56 DNA, isozyme, and antigen markers whose order on chromosome 11p is known. These cell lines appear to carry single, coherent segments of 11p spanning MIC1, which range in size from 3000 kb to more than 50,000 kb and which are generally stable in the absence of selection. In addition to the selected region of 11p13, two cell lines carry extra fragments of the human centromere and two harbor small, unstable segments of 11p15. As a first step to determine the size and molecular organization of the WAGR gene complex, we analyzed a subset of reduced hybrids by pulsed-field gel electrophoresis. A small group of NotI restriction fragments comprising the WAGR complex was detected in Southern blots with a cloned Alu repetitive probe. One of the cell lines (GH3A) was found to carry a stable approximately 3000-kb segment of 11p13 as its only human DNA. The segment encompasses MIC1, a recurrent translocation breakpoint in acute T-cell leukemia (TCL2), and most or all of the WAGR gene complex, but does not include the close flanking markers D11S16 and delta J. This hybrid forms an ideal source of molecular clones for the developmentally fascinating genes underlying the WAGR syndrome.

Animals↗
PubMed1990

Identification of two human ferritin H genes on the short arm of chromosome 6.

We have found by analyses of human-hamster hybrid cells that two human ferritin H genes lie near the locus of the iron storage disease idiopathic hemochromatosis on chromosome 6p. One of these genes was isolated and shown to be a processed pseudogene. Comparison of its sequence with those of other ferritin H pseudogenes indicates that they may be derived from a functional H gene other than that on chromosome 11.

Animals↗
PubMed1990

Definition of the limits of the Wilms tumor locus on human chromosome 11p13.

In a previous report, we described a contiguous restriction map of chromosome band 11p13 that localized the Wilms tumor locus to a small group of NotI fragments. In an effort to identify and isolate the 11p13-associated sporadic Wilms tumor locus, we developed a panel of NotI fragment-specific DNA probes. These probes were selected from genomic libraries constructed using the Chinese hamster ovary-human somatic cell hybrid carrying only human 11p. The libraries were prepared from NotI-digested DNA after size selection by pulsed-field gel electrophoresis. The selected NotI fragments had been previously targeted on the basis of deletion mapping as having a high probability of containing the Wilms tumor locus. We used these newly identified 11p13-specific probes to improve the resolution of the restriction map spanning the Wilms tumor locus. The locus has been defined by a homozygous deletion in a sporadic Wilms tumor. Using these probes, the region of homozygous deletion in this tumor and presumably all or part of the Wilms tumor gene have been confined to two small SfiI fragments spanning less than 350 kb.

Animals↗
PubMed1990

Molecular characterization of trimethoprim resistance in Shigella sonnei in Sicily.

During the 3-year period 1985-7, all strains of Shigella sonnei isolated in Catania, Sicily, showed a high level of resistance to trimethoprim (Tp) which was invariably associated with resistance to other antibiotics. Plasmid analysis showed 18 different electropherotypes: 35 of 37 strains harboured a plasmid of 70 Megadaltons (MDa), and 29 of 37 strains a plasmid of 130 MDa. Restriction endonuclease fingerprinting of purified 70 MDa plasmid DNA from different strains demonstrated that these plasmids were similar but not identical. In some strains with transferable Tp resistance, DNA hybridization analysis demonstrated the presence of gene coding for the production of dihydrofolate reductase (DHFR) type V. In contrast, there was no detectable hybridization with DNA probes specific for genes coding for DHFR types I, II and IV. This is the first report of the DHFR type V gene outside Sri Lanka.

Conjugation, Genetic↗
PubMed1990

Reduced tumour growth of the human colonic cancer cell lines COLO-320 and HT-29 in vivo by dietary n-3 lipids.

Seventy-five nude mice received subcutaneous inoculation with 1 X 10(7) cells of the human colonic cancer cell lines COLO-320 or HT-29. Tumour growth was assessed over 4 weeks in animals given one of three iso-caloric diets; standard diet, high saturated fat (20% coconut) diet and high n-3 fat (20% Maxepa fish oil) diet. The n-3 diet produced significant tumour growth reduction compared to the other diets for COLO-320 at 3 to 4 weeks (P less than 0.05 at least) and similarly for HT-29 at 4 weeks (P less than 0.05). Significant incorporation of n-3 fatty acids occurred in red cell membranes, adipose tissue and both neutral lipid and phospholipid fractions of tumour lipids in animals fed Maxepa (P less than 0.01 at least). This was accompanied by reduction of linoleic acid and arachidonic acid in these tissues (P less than 0.01 at least) but was most marked in the metabolically labile phospholipid fraction. There was high mitotic activity in the tumours from all the groups but there was no difference according to diet.

Animals↗
PubMed1990

Reduction in hospital time to thrombolytic therapy by audit of policy guidelines.

Despite the importance of early thrombolysis in the treatment of acute myocardial infarction, unacceptable delays in drug administration still occur in hospital. From March 1989 we decided to monitor our performance, and thereby to reduce avoidable in-hospital delay to a minimum. Potential candidates for thrombolytic therapy were identified by paramedic ambulancemen whenever this was feasible. Rapid check-lists were used for inclusion and exclusion criteria in the Accident and Emergency Department. A target of 15 min was set for time to treatment, and reasons for any gross deviation (greater than 30 min) were explored in each instance. As a result of these strategies, we achieved a median time from admission to initiation of thrombolysis in 50 consecutive patients of 17 min. The 39 patients treated with injections of APSAC as opposed to infusions of streptokinase had a median in-hospital delay to treatment of only 13 min.

Aged↗
PubMed1990

Resource needs of an occupational health service to accommodate a hepatitis B vaccination programme.

The administrative, organizational and clinical commitment of an occupational health department to implement the DHSS recommendation for a hepatitis B vaccination programme for the health care workers in a District General Hospital was reviewed to evaluate the resource implications needed to accommodate the additional workload. The deficiencies observed in the existing DHSS guidance in implementing the plan are described. It is suggested that the Department of Health, while making future recommendations for vaccination, should be more precise in identifying those at risk, in describing the desired titre to be achieved after vaccination, and in describing the follow-up plan for those who accept the vaccination, those who refuse and those who do not seroconvert. The recommendation should describe the commitment of the Health Authorities and must include recommendations for appropriate and adequate resources to support such a programme. Vaccination for 1000 employees at risk required 4000 additional consultations necessitating 16 additional hours of occupational health commitment per week. Eighteen months after initiating the vaccination programme, 677 employees had accepted the vaccine. After receiving 3 vaccines 508 (75 per cent) recipients had protective seroconversion (anti-Hbs greater than 100 I.U.) and a further 61 (9 per cent) converted after the 4th injection, thereby offering protective immunity to 84 per cent of the recipients. During the period 84 (12.4 per cent) were lost to follow-up. Recommendations have been made to accommodate the additional commitment through the vaccination programme to standardize our care and prevent disruption of the existing service.

Health Plan Implementation↗
PubMed1990

The gene for the alpha 2 chain of the human fibrillar collagen type XI (COL11A2) assigned to the short arm of chromosome 6.

A cosmid clone (CosHcol.11) containing the alpha 2(XI) collagen gene (COL11A2) has been isolated. The gene contains conserved DNA and amino-acid sequences characteristic of fibril forming collagen, which is in accordance with the classification of type XI collagen as a fibrillar collagen. The genomic clone containing the alpha 2(XI) gene has been used as probe in the Southern blot analysis of DNA from a panel of human/hamster somatic cell hybrids containing different numbers and combinations of human chromosomes. Synteny analysis revealed that only chromosome 6 showed complete concordant segregation with COL11A2. Furthermore, the gene was regionally mapped to the short arm of chromosome 6 by using a hybrid which contained only the long arm of the chromosome.

Blotting, Southern↗
PubMed1990

Cloning and characterization of the aroA gene from Mycobacterium tuberculosis.

The aroA gene from Mycobacterium tuberculosis has been cloned by complementation of an aroA mutant of Escherichia coli after lysogenization with a recombinant DNA library in the lambda gt11 vector. Detailed characterization of the M. tuberculosis aroA gene by nucleotide sequencing and by immunochemical analysis of the expressed product indicates that it encodes a 5-enolpyruvylshikimate-3-phosphate synthase that is structurally related to analogous enzymes from other bacterial, fungal, and plant sources. The potential use of the cloned gene in construction of genetically defined mutant strains of M. tuberculosis by gene replacement is proposed as a novel approach to the rational attenuation of mycobacterial pathogens and the possible development of new antimycobacterial vaccines.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1990

Analysis of the transcriptional promoter which regulates the latency-related transcript of bovine herpesvirus 1.

As a transcriptional promoter in primary cultures of sensory ganglionic neurons, DNA sequences near the 5' terminus of the latency-related (LR) gene of bovine herpesvirus 1 were at least 10 times more efficient than the simian virus 40 early promoter-enhancer. In contrast, as a promoter in bovine, rodent, or monkey cells, the LR promoter was approximately six times less efficient than the simian virus 40 early promoter-enhancer. The LR promoter had strict orientation preferences in neurons and all other mammalian cell lines tested. Removal of a 146-base-pair XhoI fragment from the LR promoter resulted in stimulation of LR promoter activity in bovine cells but not rabbit neurons, monkey fibroblasts, or rodent cells. LR promoter activity in bovine cells is stimulated by bovine herpesvirus 1 lytic infection, suggesting that viral gene products or virus-induced factors positively regulate the expression of the LR gene. A synthetic glucocorticoid, dexamethasone, repressed LR promoter activity in bovine cells. These results imply that a variety of factors can influence the expression of the LR gene during latent infections of neurons as well as during the lytic infection cycle.

Acetylation↗
PubMed1990

Slip-shod or safely shod: the bighorn sheep as a natural model for research.

Over a million injuries caused by slipping of footwear are believed to require treatment by doctors every year in the United Kingdom and many domestic animals are injured by slipping. Recent research has revealed that surface roughness of solings and floors is an important determinant of grip on lubricated surfaces and it is also known that soling friction is affected by hardness. The bighorn sheep (Ovis canadensis) an animal species which has adapted to a slippery environment, was studied to elucidate optimum roughness and hardness and other features which influence grip. Four adult ewes were examined in the London Zoo. The cloven hooves of this species are very mobile and the cranial tips of the hooves are the first parts to make contact with the ground. A very small contact area ensures penetration of a film of water. Mean roughness of the contact area was found to be 53 microns Rtm and the mean hardness 63 Shore A. These characteristics appear to facilitate an excellent grip on wet slippery rock but not on smooth ice. Further studies of the feet of wild species could contribute to an understanding of the factors which determine the safety of solings and floors.

Accident Prevention↗
PubMed1990

Effects of sodium intake, furosemide, and infusion of atrial natriuretic peptide on the urinary and metabolic clearances of arginine vasopressin in normal subjects.

Arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) have important influences on water and electrolyte metabolism, and studies on the interactions between these hormones may have important implications. We have investigated the effects of sodium intake, furosemide, and infusion of ANP on the urinary and metabolic (nonurinary) clearances of AVP in hydrated normal subjects. On a high sodium diet there was an increase in urine volume, sodium excretion, osmolal clearance, plasma ANP concentration, and urinary clearance and fractional excretion of AVP, with a decrease in PRA. The infusion of furosemide increased urine volume, sodium excretion, osmolal clearance, and PRA, but decreased circulating ANP levels and urinary clearance and fractional excretion of AVP. Since there was a positive correlation between circulating ANP and urinary clearance of AVP in these experiments, we infused human alpha ANP in physiological amounts and found increases in the urinary and metabolic (nonurinary) clearances of AVP. The changes in urinary clearance of AVP in all three experiments occurred even in relation to creatinine clearance. These observations demonstrate that urinary clearance of AVP does not correlate with urine volume, sodium or solute excretion, or PRA. The observations support a physiological role for ANP in modulating the renal action of AVP, probably at the level of the renal tubules, and indicate a need for caution when using plasma or urinary AVP as an indicator of AVP release from the neurohypophysis.

Adult↗
PubMed1990

IgG subclass concentrations in absolute, partial and transient IgA deficiency in childhood.

Sixty-seven children with symptomatic IgA deficiency were studied on two separate occasions. Eighteen had aIgAd at presentation, and 49 had pIgAd. IgA concentrations had risen to the normal range for age in 22.2% of children presenting with aIgAd and 77.6% presenting with pIgAd when restudied at a median interval of 3.2 and 3.0 years, respectively. IgG subclass concentrations were measured by enzyme immunoassay in serum samples collected at enrollment from 12 children with aIgAd and 22 children with pIgAd. IgG2 and IgG4 concentrations for these 34 children were below the 5th centile for age and sex more frequently than expected (IgG2: chi square 5.8, P less than 0.025; IgG 4: chi square 18.4, P less than 0.0005). The prevalence of IgG2 deficiency or IgG4 deficiency did not differ significantly between those with aIgAd and those with pIgAd. IgG2 concentrations remained below the 5th centile more frequently than expected when retested in 31 children whose pIgAd had resolved (chi square 4.6, P less than 0.05). Children with aIgAd at presentation had IgG1 and IgG2 concentrations above the 95th centile more frequently than expected (IgG1: chi square 19.7, P less than 0.0005; IgG2: chi square 13.5, P less than 0.001) but this was not seen for IgG3 and IgG4 concentrations. Children with pIgAd did not have elevated IgG1 or IgG2 concentrations at presentation. High IgG1 and IgG2 concentrations in aIgAd may be a compensatory mechanism to afford protection from infection or could be part of a selective secondary response to repeated episodes of infection.

Adolescent↗
PubMed1990

Chancroid: results from an outbreak in Houston, Texas.

A recent (and continuing) epidemic of chancroid in Houston has included morphologic variation in the disease, including so-called dwarf, classic, giant, transient, follicular, phagedenic, and pseudogranuloma inguinale types. Most cases were clearly acquired by unprotected sexual encounters with local prostitutes. The strain of Haemophilus ducreyi responsible for this outbreak was relatively easily cultured on routine media; unexpected sensitivity of this strain to vancomycin rendered the recommended "selective" growth medium much less optimal for isolation. Therapeutic success uniformly followed the use of intramuscular ceftriaxone sodium; one case responded to oral ciprofloxacin hydrochloride.

Administration, Oral↗
PubMed1990

Cutaneous cryptococcosis simulating Kaposi's sarcoma in the acquired immunodeficiency syndrome.

A forty-one-year-old homosexual man with acquired immunodeficiency syndrome (AIDS) and biopsy proven Kaposi's sarcoma of the oral cavity presented to our clinic with a several month history of violaceous papules and plaques on his trunk and extremities. Although the patient already carried a clinical diagnosis of Kaposi's sarcoma, several biopsies of skin lesions were performed. Tissue specimens demonstrated cutaneous infection with Cryptococcus neoformans. As patients with AIDS have an increased incidence of both Kaposi's sarcoma and opportunistic infections, all progressing lesions should be biopsied in order to avoid missing a treatable life-threatening disease.

Acquired Immunodeficiency Syndrome↗