PubMed Health⌕ Search

Biomedical subjects

D H Jones

Publications and source records attributed to D H Jones.

At least 19 recordsLinked to original sources
PubMed1992

Stability and detection of recombinant pre-pro-concanavalin A after cytoplasmic expression in Escherichia coli.

The cDNA for pre-pro-concanavalin A (pre-pro-Con A) from Canavalia ensiformis was used to construct two cytoplasmic expression vectors: pKconA (no transcription terminator) and pTKconA (containing the cry transcription terminator). The latter produced 2- to 3-fold greater amounts of pre-pro-Con A. This product containing the plant signal can be detected by Western blotting only after electrophoretic transfer in the presence of SDS, indicating reduced solubility. The signal is not removed and pre-pro-Con A is clearly stable after expression in E. coli JM109. The protein is not cleaved and ligated as in the plant, in contrast to a recent report.

Blotting, Western↗
PubMed1992

Cutaneous malignant melanoma, Scotland, 1979-89. The Scottish Melanoma Group.

The Scottish Melanoma Group (SMG) was established in 1979 to assess mortality from and incidence, features, pathological data, and management of cutaneous malignant melanoma in Scotland. Incidence during the first five years and five-year survival have already been reported. We now have data about incidence and mortality over eleven years in relation to anatomical site and pathological types. From 1979 to 1989, 1354 male and 2459 female patients with primary cutaneous malignant melanomas were first diagnosed in Scottish residents. The incidence rate per 100,000 population per year has increased from 3.4 in 1979 to 7.1 in 1989 for men, and from 6.6 to 10.4 for women. The overall increase over eleven years is 82% (7.4% per year). The greatest rates of increase are seen in lesions of the superficial spreading histogenetic type, arising on the female leg and the male trunk. Following public education programmes started in 1985, the proportion of all melanomas less than 1.5 mm thick has shown a sustained and significant increase. Mortality data for 1661 patients for whom a minimum of five-year follow-up is available shows five-year survival of 71.6% overall (77.6% for women, 58.7% for men). The survival advantage for women persists when appropriate statistical adjustment is made for thickness, ulceration, and histogenetic type. These data are useful in designing public education programmes aimed at both primary and secondary prevention of melanoma and in auditing changes in trends that might result from such education.

Adolescent↗
PubMed1992

Sequence specific generation of a DNA panhandle permits PCR amplification of unknown flanking DNA.

We present a novel method for the PCR amplification of unknown DNA that flanks a known segment directly from human genomic DNA. PCR requires that primer annealing sites be present on each end of the DNA segment that is to be amplified. In this method, known DNA is placed on the uncharacterized side of the sequence of interest via DNA polymerase mediated generation of a PCR template that is shaped like a pan with a handle. Generation of this template permits specific amplification of the unknown sequence. Taq (DNA) polymerase was used to form the original template and to generate the PCR product. 2.2 kb of the beta-globin gene, and 657 bp of the 5' flanking region of the cystic fibrosis transmembrane conductance regulator gene, were amplified directly from human genomic DNA using primers that initially flank only one side of the region amplified. This method will provide a powerful tool for acquiring DNA sequence information.

Base Sequence↗
PubMed1992

Non-glycosylated recombinant pro-concanavalin A is active without polypeptide cleavage.

The complex post-translational processing of concanavalin A (Con A) in maturing jackbeans is unique because the non-glycosylated mature active protein is circularly permuted in primary sequence relative to its own inactive precursor (glycosylated pro-Con A) and to other legume lectins. We show here that non-glycosylated pro-Con A expressed in bacteria from recombinant cDNA (rec-pro-Con A) folds in vivo and in vitro to a stable form which is active without further processing. N-glycosylation alone must therefore be sufficient to inactivate pro-Con A--a novel role for glycosylation in regulating activity during protein maturation.

Base Sequence↗
PubMed1992

Living arrangements, knowledge of health risks, and stress as determinants of health-risk behavior among college students.

The association of knowledge of health risks, living arrangements, and perceived stress with health-risk behaviors was examined in a sample of college students included in the Health Promotion and Disease Prevention Supplement of the National Health Interview Survey. Regressions of each health-risk behavior (dependent variable) were performed on the predicted correlates. Although knowledge was not associated with participation in physical activity or smoking, the study found that students who knew more about the harmful effects of alcohol drank less, and those with greater knowledge of health risks practiced fewer risky behaviors. Students living independently were more likely to smoke, and those living in residence halls were less like to do so. Drinking, however, was more common among students living in residence halls or independently than among those living at home. Hall residents engaged in more group physical activity than other students did, but their physical activity was unrelated to health-risk behaviors. Stress was associated with smoking but not with other health practices. The findings suggest that smoking may be less influenced by health knowledge and more associated than drinking is with a response to stress. Drinking appears to be a social activity associated with living among peers and is potentially modifiable by increased knowledge about the effects of alcohol on health.

Adolescent↗
PubMed1992

Nucleotide sequence of the structural gene encoding a 2-haloalkanoic acid dehalogenase of Pseudomonas putida strain AJ1 and purification of the encoded protein.

The nucleotide sequence of a gene encoding an L-2-haloalkanoic acid halidohydrolase from Pseudomonas putida strain AJ1 was determined. The ORF (hadL) codes for a polypeptide of 227 amino acids (Mr 25,687) which has significant homology to two other L-2-haloalkanoic acid halidohydrolases of Pseudomonas sp., DehcI and DehcII; these show 38% and 51% amino acid identity respectively to HadL. All three enzymes produce products of an opposite optical configuration to that of the substrates. Comparison of the three sequences shows several highly conserved motifs which indicate the possible position of the enzyme active site. The enzyme was purified to homogeneity and appears to exist as a tetramer.

Amino Acid Sequence↗
PubMed1992

Recombinant circle PCR and recombination PCR for site-specific mutagenesis without PCR product purification.

Two simple methods for site-specific mutagenesis are described and compared. In each method, the PCR is used in two separate amplifications to mutate the site of interest and to add ends to one PCR product that are homologous to the ends of the other PCR product. In the first method, the two products are combined, denatured and reannealed prior to transformation of E. coli in order to form recombinant circles in vitro, while in the second method, the two linear products are co-transfected directly into E. coli without prior manipulation, resulting in transformation of E. coli with the recombinant of interest by recombination in vivo. Each PCR amplification uses a plasmid template that has been linearized by restriction enzyme digestion outside the region to be amplified. This permits use of unpurified PCR products in these two protocols and generation of the mutant of interest with no other enzymatic manipulation in vitro apart from PCR amplification. In each protocol greater than or equal to 50% of the resulting clones contained the mutation of interest without detected errors.

Base Sequence↗
PubMed1991

Cardiovascular health knowledge in the United States: findings from the National Health Interview Survey, 1985.

Knowledge of the risk precursors to cardiovascular disease is thought to be a key component of health decision making. Many intervention programs have been aimed at increasing the nation's general knowledge of risk factors for cardiovascular disease, although the determinants of the level of cardiovascular disease knowledge are not thoroughly understood. We examined cardiovascular knowledge in a nationally representative sample of the United States population with data from the 1985 Health Promotion and Disease Prevention supplement of the National Health Interview Survey. Interviews with 12,551 white women, 770 Hispanic women, 2,547 black women, 9,832 white men, 576 Hispanic men, and 1,440 black men were used in this analysis. We constructed a seven-item index for cardiovascular disease knowledge. After adjustment for age and education, white men and women scored higher on the cardiovascular disease knowledge index than either their Hispanic or black counterparts. We also examined the relationships of age, education, income, marital status, access to medical care, geographic region, and seven self-reported cardiovascular disease risk factors to the levels of cardiovascular disease knowledge. Education was the strongest predictor of cardiovascular disease knowledge. The variables examined accounted for a small portion of the variance in knowledge. Levels of cardiovascular disease knowledge were lower among respondents with less education and income, those who were not married, those with less access to medical care, and those who were smokers or physically inactive. Therefore, efforts to improve levels of cardiovascular disease knowledge should be directed toward subgroups.

Age Factors↗
PubMed1991

Successful use of subcutaneous recombinant human erythropoietin before cholecystectomy in an anemic patient with religious objections to transfusion therapy.

Use of recombinant human erythropoietin has been advocated for therapy in anemic patients with end-stage renal disease and to enhance the harvesting of autologous red blood cells from healthy patients scheduled for elective orthopedic surgery. The authors report the case of a diabetic patient with moderate chronic renal failure and cholelithiasis but whose religious beliefs forbade the use of transfusion therapy. She underwent successful cholecystectomy only after treatment with recombinant human erythropoietin.

Anemia↗
PubMed1991

A rapid method for recombination and site-specific mutagenesis by placing homologous ends on DNA using polymerase chain reaction.

We have developed a novel polymerase chain reaction (PCR) method that permits the rapid generation of site-specific mutants and recombinant DNA constructs with a minimum number of steps and primers. DNA segments are modified by using amplifying primers that add homologous ends to the polymerase chain reaction product(s). These homologous ends undergo recombination in vivo following transformation of recA-E. coli strains used routinely in cloning. In vivo circularization of PCR products containing plasmid sequences with a selective marker permits the rapid cloning of the desired mutant or recombinant. In the mutagenesis protocol, 7 of the 12 clones contained the product of interest, and 6 of these clones had no detected error (50% of the clones without detected errors). In each of several recombination protocols, at least 50% of the clones tested contained the insert of interest without detected errors.

Base Sequence↗
PubMed1991

Fluid therapy in the PACU.

The goal of fluid therapy in the PACU setting is the restoration of blood volume and tissue perfusion. Choosing the type of fluid infusion depends on the preoperative, intraoperative, and postoperative condition of the patient. An understanding of the functional fluid compartments, the composition of body fluids and commercially available fluids, and the steps to evaluate fluid depletion allow one to determine the fluid needs of the patient. The orderly and expedient evaluation of fluid status of the postoperative patient involves the assessment of volume status, concentration status, composition status, and signs and symptoms of inadequate tissue perfusion. Recovery after surgery is a dynamic process, and fluid reassessment should be conducted periodically. Fluid challenges may be necessary in the hypovolemic patient or in patients with clear signs and symptoms of end-organ hypoperfusion. Weil and Rackow and Shoemaker provide useful approaches to fluid challenge guided by CVP and PAP monitoring. The decision of whether to use crystalloids or colloids for fluid resuscitation is complex, controversial, often determined by personal preference and concern over expense, and may be inconsequential as long as fluids are infused appropriate to the needs of the patient. There are disadvantages and advantages to both crystalloid and colloid fluid administration. As with any therapeutic intervention, there are complications with fluid administration, congestive heart failure and pulmonary edema being of more immediate concern. Finally, blood components are colloid-type solutions that should be reserved for specific patient problems. Red blood cells are indicated to increase oxygen-carrying capacity in patients with anemia. Platelets are used to treat bleeding associated with deficiencies in platelet number or function. Fresh frozen plasma is transfused to increase clotting factor levels in patients with demonstrated deficiency. A good understanding of fluid types available, of a systematic approach to evaluating fluid depletion, and of the indications for blood component therapy will allow one to make appropriate decisions when implementing fluid therapy in the PACU.

Blood Transfusion↗
PubMed1990

DNA mutagenesis and recombination.

The polymerase chain reaction is used for site-specific mutagenesis and for DNA recombination without any enzymatic reaction in vitro, apart from DNA amplification.

DNA, Circular↗
PubMed1990

Trauma services requirements in a district general hospital serving a rural area.

OBJECTIVE: To assess the demands made on a regional trauma centre by a district trauma unit. DESIGN: Two part study. (1) Prospective analysis of one month's workload. (2) Retrospective analysis of one year's workload by using a computer based records system. Comparison of two sets of results. SETTING: Accident unit in Gwynedd Hospital, Bangor. PATIENTS: (1) All patients who attended the accident unit in August 1988. (2) All patients who attended the accident unit in the calendar year April 1988-April 1989. MAIN OUTCOME MEASURE: Workload of a district trauma unit. RESULTS: In August 1988 there were 2325 attendances; 2302 of these were analysed. In all, 1904 attendances were for trauma; 213 patients were admitted to the trauma ward and 103 required an operation that entailed incision. Patients who attended the unit had a mean (range) injury severity score of 2-13 (0-25). Only two patients had injuries that a district general hospital would not be expected to cope with (injury severity score greater than 20). In the year April 1988-April 1989, 21,007 patients attended the unit. In all, 17,958 attendances were for orthopaedic injuries or injuries caused by an accident; 1966 patients were admitted to the unit. CONCLUSIONS: Most trauma is musculoskeletal and relatively minor according to the injury severity score. All but a few injuries can be managed in district general hospitals. In their recent report the Royal College of Surgeons has overestimated the requirements that a British district general hospital would have of a regional trauma centre.

Catchment Area, Health↗
PubMed1990

Subcellular distribution and mobilization of MAC-1 (CD11b/CD18) in neonatal neutrophils.

The CD11b/CD18 (Mac-1) heterodimeric surface glycoprotein contributes to a broad range of adherence-dependent neutrophil inflammatory functions. Previous investigations have indicated that diminished expression or regulation of Mac-1 may underlie abnormalities of stimulated adhesion and chemotaxis of neonatal neutrophils in vitro and inflammatory deficits in human neonates. To define the pathogenic mechanisms contributing to these findings, we compared the distribution and translocation of Mac-1 in subcellular fractions of neonatal and adult neutrophils before and after chemotactic stimulation. The total cell content of Mac-1 and the proportions of Mac-1 in beta fractions (vitamin B12 binding protein-rich granules), pre-gamma fractions (gelatinase-rich granules), or gamma fractions (plasma membrane) of neonatal neutrophils were comparable with those of adult neutrophils. However, after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP; 10 nmol/L, 37 degrees C, 15 minutes), neonatal neutrophils demonstrated (1) diminished translocation of Mac-1 from pre-gamma fractions (P less than .05), and (2) diminished surface expression of Mac-1 (P less than .05), as compared with healthy adult neutrophils. As shown in enzymatic and immunochemical assays, neonatal cells contained significantly (P less than .01) diminished levels of neutrophil gelatinase. In response to FMLP (0.1 to 10 nmol/L, 37 degrees C, 15 minutes), neonatal suspensions also released significantly (P less than .001) less gelatinase, as compared with adult neutrophil suspensions. These observations demonstrate that diminished mobilization of Mac-1 from gelatinase-rich granular pools in neonatal neutrophils is associated with abnormal surface expression of this glycoprotein after chemotactic stimulation. This abnormality may contribute, in part, to abnormal migratory properties of neonatal neutrophils in response to inflammatory stimuli.

Antigens, Differentiation↗
PubMed1990

High dose intensity combination chemotherapy for advanced epithelial ovarian carcinoma: results of a pilot study.

Retrospective studies have recently demonstrated a significant correlation between dose intensity of chemotherapy and response rates and survival in various diseases including epithelial ovarian carcinoma. As part of a proposed randomised trial to assess the effect of dose intensity on outcome in ovarian carcinoma, a pilot study has been undertaken to determine the toxicity and efficacy of the high intensity therapy. Nineteen patients with advanced ovarian carcinoma received initial treatment with cisplatin 120 mg m-2 i.v. day 1, and cyclophosphamide 1,000 mg-2 i.v. day 1, given at 21-day intervals for six cycles. The average relative dose intensity of this therapy is 1.14 when compared with the CHAP regimen. Severe toxicity was experienced by most patients. The median received average relative dose intensity was 0.90, with only one patient receiving treatment to the proposed intensity. Randomised studies of the effect of dose intensity in ovarian carcinoma are essential, but an initial step must be to assess whether the proposed high dose treatment can be delivered.

Adult↗
PubMed1990

Health risk factors among the Amish: results of a survey.

The Amish are a unique societal subgroup deliberately setting themselves apart from the modern world through religious beliefs and practices. Few reports and no systematic studies have been conducted on Amish health behaviors. A representative sample of 400 Amish adults residing in Holmes County, Ohio, were interviewed using the Behavioral Risk Factor Survey (BRFS). For comparison, a representative sample of 773 non-Amish adults responded to the same survey through telephone interviews. Prevalence of self-reported hypertension was lower among Amish than non-Amish, obesity was greater among Amish than non-Amish women but similar among men, and stress responses were more prevalent among Amish than non-Amish. While some differences between groups could be influenced by response biases, many are supported by less systematic observations of Old Order Amish societies. Patterns of health behavior reflect characteristics of Amish culture and may be responsible for certain favorable mortality rates among the Amish population. Need for cultural sensitivity is evident in health promotion program design and implementation.

Adolescent↗
PubMed1990

A rapid method for site-specific mutagenesis and directional subcloning by using the polymerase chain reaction to generate recombinant circles.

Site-specific mutagenesis and directional subcloning were accomplished by using the polymerase chain reaction to generate products that can recombine to form circular DNA. This DNA was transfected into E. coli without phosphorylation of primers, restriction enzyme digestion or ligation. Specifically, the polymerase chain reaction was used to generate products that when combined, denatured and reannealed, form double-stranded DNA with discrete, cohesive single-stranded ends. The generation of these cohesive ends of DNA permits the formation of precise, directional DNA joints without dependence on enzyme restriction sites. The primers were designed such that these cohesive single-stranded ends annealed to form circular DNA. The recombinant of interest was generated following only 14 amplification cycles. These recombinant circles of DNA were directly transfected into E. coli. In the mutagenesis protocol, the desired mutant was obtained at 83%-100% efficiency. Unwanted mutations were not detected, indicating a less than 0.025% nucleotide misincorporation frequency. In the directional subcloning protocol, inserts were positioned precisely in the recipient plasmid and were in the correct orientation. One unwanted mutation was detected after sequencing 900 bases, indicating a 0.11% nucleotide misincorporation frequency. Each manipulation, from setting up for the DNA amplification to transfection into E. coli. can easily be accomplished in one day.

Base Sequence↗