PubMed Health⌕ Search

Biomedical subjects

M J Jones

Publications and source records attributed to M J Jones.

At least 19 recordsLinked to original sources
PubMed2006

Assessment of reproducibility and accuracy in templating hybrid total hip arthroplasty using digital radiographs.

In 20 patients undergoing hybrid total hip arthroplasty, the reproducibility and accuracy of templating using digital radiographs were assessed. Digital images were manipulated using either a ten-pence coin as a marker to scale for magnification, or two digital-line methods using computer software. On-screen images were templated with standard acetate templates and compared with templating performed on hard-copy digital prints. The digital-line methods were the least reliable and accuracy of sizing compared with the inserted prostheses varied between -1.6% and +10.2%. The hard-copy radiographs showed better reproducibility than the ten-pence coin method, but were less accurate with 3.7% undersizing. The ten-pence coin method was the most accurate, with no significant differences for offset or acetabulum, and undersizing of only 0.9%. On-screen templating of digital radiographs with standard acetate templates is accurate and reproducible if a radiopaque marker such as a ten-pence coin is included when the original radiograph is taken.

Acetabulum↗
PubMed2005

Egg size-number trade-off and a decline in oviposition site choice quality: female Pararge aegeria butterflies pay a cost of having males present at oviposition.

Once mated, the optimal strategy for females of the monandrous butterfly, Pararge aegeria, is to avoid male contact and devote as much time as possible to ovipositing, as there is little advantage for females to engage in multiple matings. In other butterfly species the presence of males during egg laying has been shown to affect aspects of oviposition behavior and it has been suggested that repeated interference from males has the potential to reduce reproductive output. The aim of this study was to assess the effects of male presence during oviposition on reproductive output and behavior of a population of P. aegeria obtained from Madeira Island, Portugal, and maintained in the laboratory. Two experiments were performed where females were housed individually in small cages. Experiment 1 examined how social factors influenced the egg laying behavior of females. To do this the presence or absence of males was manipulated and egg size and number was measured over the first 14 days of oviposition. It was observed that when males were present during oviposition females made a trade-off between egg size and number. Experiment 2 examined how social factors affected oviposition site choice. Again, male presence/absence was manipulated, but in this experiment where the female laid her egg in relation to host quality was scored, and the size of the egg laid was measured. In the absence of males females selectively positioned their larger eggs on good quality host plants. However, selective oviposition was no longer observed when females were in the presence of males. We suggest that P. aegeria females from the Madeira Island population are adapted for a flexible oviposition strategy, governed by external cues, allowing a trade-off between egg size and number when the time available for egg laying is limiting.

Animals↗
PubMed2005

Developing an accurate system of measuring colour in a venous leg ulcer in order to assess healing.

OBJECTIVE: To develop a standardised method of assessing venous ulceration, based on the colour of an ulcer bed and the surrounding skin. METHOD: This pilot study involved taking three sequential digital photographs during an episode of care and measuring the colour using image analysis software. Ten episodes of care were used for data collection. RESULTS: Based on previous research, a threshold of < or =3 degrees of colour and 3% of saturation was selected to indicate the reliability of the system. The mean of the colour measurements was inside the reliability threshold when measuring an ulcer bed, but outside the threshold for measuring the surrounding skin. CONCLUSION: The results indicate that the system provides consistent visual representation of a venous leg ulcer.

Aged↗
PubMed2001

Efficacy of cisapride and domperidone in functional (nonulcer) dyspepsia: a meta-analysis.

BACKGROUND: The efficacy of prokinetic agents in functional (nonulcer) dyspepsia has been questioned based on recent trial results. We performed a meta-analysis to determine the efficacy of cisapride and domperidone in functional dyspepsia. METHODS: Computer and manual searching was used to identify placebo-controlled studies that included >20 patients. The statistical analysis focused on: global assessment by the investigator, epigastric pain, early satiety, abdominal distension and nausea (all rated on four-point scales). Results are reported as odds ratios (OR) in favor of treatment. Regression analysis was performed to evaluate possible effect modifiers. The relationship between improvement in gastric emptying and symptoms was also evaluated. RESULTS: For cisapride, 17 studies met the inclusion criteria, but varying numbers of studies had to be used for the different outcome measures. For all outcome measures, there was a statiscally significant benefit in favor of cisapride: global assessment of improvement by the investigator or patient (OR 2.9, 95% CI 1.5-5.8), epigastric pain (OR 0.19, 95% CI 0.05-0.7), early satiety (OR 0.18, 95% CI 0.9-0.4), abdominal distension (OR 0.32, 95% CI 0.1-0.7), and nausea (OR 0.26, 95% CI 0.1-0.5). Age of patient, year of publication, and country where study was performed had only small modifying effects. There were insufficient data to determine whether there is a relationship between improvement in gastric emptying and response to treatment. For domperidone, four of eight studies could be used for the analysis of global assessment of improvement by the investigator. This showed an OR of 7.0 (95% CI 3.6-16) in favor of domperidone. CONCLUSIONS: Both cisapride and domperidone seem to be efficacious in functional dyspepsia, although this conclusion is largely based on global assessment by the investigator, which may not be an optimal outcome measure.

Cisapride↗
PubMed2000

Composition of alveolar surfactant changes with training in humans.

OBJECTIVE: We test the hypothesis that the changes we observed previously in the relative amounts of disaturated phospholipids (DSP), cholesterol (CHOL), and surfactant protein-A (SP-A) in human alveolar surfactant in response to acute exercise, and which were related to fitness, can be induced by training. METHODOLOGY: We examine the effect of 7 weeks' training on these major surfactant components, together with surfactant protein-B (SP-B), in bronchoalveolar lavage fluid harvested from 17 males, both at rest and after acute exercise. Fitness was assessed as workload/heart rate achieved during cycling for 30 min at 90% of theoretical maximal heart rate, and was increased in all subjects following training (mean increase 22.2+/-3.91%; P = 0.001). RESULTS: Training significantly increased the SP-A/DSP, SP-B/DSP, SP-A/CHOL and SP-A/SP-B ratios in whole surfactant harvested from subjects both at rest and immediately following exercise. Training also increased the SP-B/CHOL ratio at rest. Changes were particularly marked at rest in the SP-A/DSP, SP-A/CHOL, and SP-B/CHOL ratios in the tubular myelin-rich fraction, and after exercise in the SP-A/DSP, SP-A/CHOL, and SP-A/SP-B ratios in the tubular myelin-poor fraction. CONCLUSION: We conclude that training markedly alters the composition of alveolar surfactant both at rest and with exercise; the physiological significance of these changes remains to be determined.

Adolescent↗
PubMed1999

Atrial, B-type, and C-type natriuretic peptides cause mesenteric vasoconstriction in conscious dogs.

Cardiovascular responses were compared with equimolar infusions of B-type (BNP) and C-type (CNP) with atrial natriuretic peptide (ANP) in conscious, instrumented dogs. On separate days, each natriuretic peptide or vehicle was infused (intravenously) at step-up doses of 2, 5, 10, and 20 pmol. kg-1. min-1 (20 min each dose) to increase circulating levels of the infused peptide from approximately 2- to 20-fold. Like ANP, infusions of BNP caused dose-related increases (P < 0.05) in mesenteric vascular resistance, urine flow, natriuresis, and hematocrit (changes at highest doses were 60 +/- 9, 334 +/- 113, 313 +/- 173, and 12 +/- 2%, respectively). BNP also lowered (P < 0. 05) plasma renin activity (-43 +/- 11%) and arterial pressure (-10 +/- 3%). Effects of BNP were independent of reflex sympathetic activation, since autonomic ganglion blockade did not attenuate the responses. CNP infusions had little effect except to increase (P < 0. 05) mesenteric vascular resistance (27 +/- 10%) and plasma ANP (41 +/- 7%). Cardiovascular actions of BNP, like those of ANP, counteract the renin-ANG system and may protect the heart by lowering cardiac preload (venous return) and afterload (arterial pressure) while maintaining blood flow to extrasplanchnic regions.

Animals↗
PubMed1997

Top-down learning of low-level vision tasks.

Perceptual tasks such as edge detection, image segmentation, lightness computation and estimation of three-dimensional structure are considered to be low-level or mid-level vision problems and are traditionally approached in a bottom-up, generic and hard-wired way. An alternative to this would be to take a top-down, object-class-specific and example-based approach. In this paper, we present a simple computational model implementing the latter approach. The results generated by our model when tested on edge-detection and view-prediction tasks for three-dimensional objects are consistent with human perceptual expectations. The model's performance is highly tolerant to the problems of sensor noise and incomplete input image information. Results obtained with conventional bottom-up strategies show much less immunity to these problems. We interpret the encouraging performance of our computational model as evidence in support of the hypothesis that the human visual system may learn to perform supposedly low-level perceptual tasks in a top-down fashion.

Algorithms↗
PubMed1997

Inclusion body myositis and transitional cell carcinoma of the bladder: significant resolution of symptoms after tumor excision.

Inclusion body myositis (IBM) is a separate class of the inflammatory myopathies with recently proposed clinical and pathological diagnostic criteria. An association between inflammatory myopathies and malignancy has been questioned in the literature. Recent reviews of the inflammatory myopathies suggest that only dermatomyositis is associated with malignancy. The largest study to date of patients with IBM found that 15% had a malignancy (6 of 40). We report the first documented case of IBM and concurrent transitional cell carcinoma of the bladder. We suggest that a causal relationship between IBM and malignancy may exist because of significantly improved functional strength gained after tumor removal.

Carcinoma, Transitional Cell↗
PubMed1997

Ceftriaxone versus cefazolin in peripheral arterial operations: a randomized, prospective trial.

Serious morbidity and mortality are associated with postoperative wound infections in peripheral vascular surgery. The use of prophylactic antibiotics is considered the standard of care, with attention focused on the most efficacious agent. A prospective, randomized study was conducted to evaluate the efficacy of ceftriaxone versus cefazolin in prevention of postoperative wound infections in a group of patients who had peripheral arterial operations between October 1991 and February 1993. Patient characteristics associated with an increased risk of postoperative wound infection were evaluated. Prophylaxis was provided for 105 operations with cefazolin and 103 operations with ceftriaxone. The overall wound infection rate was 3.85%. Six operations (5.7%) in the cefazolin group were complicated by wound infection versus 2 operations (1.9%) in the ceftriaxone group. Diabetes (6 infections/64 operations; infection rate, 9%) and a personal history of previous aortocoronary bypass (5 infections/49 operations; infection rate, 10%) were characteristics associated with an increased chance for postoperative wound infection. Ceftriaxone is therapeutically equivalent to cefazolin in the prevention of postoperative wound infections in peripheral vascular surgery.

Aged↗
PubMed1997

Autologous blood collection in anemic patients using low-dose erythropoietin therapy.

Autologous donation of blood for use during elective surgery is being recommended and used more frequently. Autologous donation and transfusion represent the safest way to handle elective surgical blood requirements because they eliminate the risk of transfusion-transmitted disease and alloimmunization, and significantly reduce the other risks associated with homologous transfusion. Many individuals, particularly women and the elderly, do not have sufficient initial hemoglobin concentration or hemopoietic reserve to effectively use autologous donation. Use of standard-dose recombinant human erythropoietin (rHuEPO) (600 units/kg) to mitigate these limitations is costly. The optimal dose, interval, and route of administration for rHuEPO therapy has yet to be perfected. This article describes a program using low-dose (< 100 units/kg) rHuEPO and also discusses the effectiveness, cost savings, and clinical indications for the use of low-dose rHuEPO.

Adolescent↗
PubMed1995

Evidence that ceramide selectively inhibits protein kinase C-alpha translocation and modulates bradykinin activation of phospholipase D.

Sphingomyelinase (SMase) treatment (0.1 unit/ml for up to 30 min) of mouse epidermal (HEL-37) or human skin fibroblast (SF 3155) cells preincubated with [3H]serine to label the sphingomyelin pool caused the accumulation of labeled ceramide but not sphingosine or ceramide 1-phosphate. Incubation of HEL-37 cells with dioctanoylglycerol (diC8) or SF 3155 cells with bradykinin caused translocation of calcium/phosphatidylserine-dependent protein kinase C (PKC) activity to particulate material. In both cell lines the translocation was blocked by SMase treatment of the cells or by incubation with the cell-permeable ceramide analogue N-acetylsphingosine (C2-Cer). Western blot analysis indicated that treatment of HEL-37 cells with diC8 or SF 3155 cells with bradykinin resulted in the translocation of both PKC-alpha and PKC-espilon to particulate material. Treatment with SMase or C2-Cer specifically blocked the translocation of PKC-alpha but not that of PKC-epsilon. Pretreatment of cells with SMase or C2-Cer also inhibited the activation of phospholipase D activity induced by either diC8 (HEL-37 cells) or bradykinin (SF 3155 cells). The data provide strong evidence that ceramide can negatively regulate the translocation of PKC-alpha but not PKC-epsilon and further suggest that PKC-alpha may be involved in regulating phospholipase D activity.

Animals↗
PubMed1995

Autologous blood donation in a small general acute-care hospital.

Increased public concerns about infectious risk associated with homologous blood transfusions have led to a significant increase in autologous blood collections. In response, blood banks and large hospitals have implemented autologous blood donation programs (ABDPs). Small hospitals lack the technical resources and patient case loads to effectively institute ABDPs. A preoperative ABDP designed to increase availability and patient convenience--and, therefore, utilization--is described. The program created in a rural 90-bed general acute-care hospital processed 105 donors and collected 197 units over a 38-month period. The percentage of the collected units that were transfused was 44.7%, and only 6.1% of participating patients required homologous transfusions. Comparisons of hematological and clinical data with previously published results indicate that small-scale preoperative ABDPs are clinically effective, safe, and provide cost-efficient utilization of the safest blood supply available.

Adolescent↗
PubMed1994

Genetic and Biochemical Characterization of Nectria haematococca Strains with Adhesive and Adhesion-Reduced Macroconidia.

A previous study reported the isolation of two mutants (LE1 and LE2) of the plant pathogenic fungus Nectria haematococca (anamorph, Fusarium solani f. sp. cucurbitae) with macroconidia with reduced ability to adhere (Att) to zucchini fruits and polystyrene. The adhesion-reduced-phenotype in LE1 and LE2 macroconidia is temperature sensitive and dependent on the concentration of nutrients. Classical genetic analysis of progeny derived from LE1 identified a mutation in a genetic locus, named Att1. The 90-kDa glycoprotein and macroconidial tip mucilage which were previously associated with the development of adhesion competence in Att macroconidia are specifically associated with macroconidia; neither is produced on microconidia, which are relatively nonadherent. However, macroconidia of both Att and Att strains produce the 90-kDa glycoprotein and the macroconidial tip mucilage.

Journal Article↗
PubMed1994

Technical note: the influence of using an atraumatic needle on the incidence of post-myelography headache.

The aim of this study was to investigate whether the incidence of headaches following myelography could be reduced by using a needle with an atraumatic tip. 107 patients were studied in a trial of 22 gauge atraumatic versus 22 gauge bevel tipped needles. In the first 3 days after myelography, there was a significant reduction in the incidence of headaches in patients in whom an atraumatic needle had been used.

Adult↗
PubMed1993

Sustainable agriculture: an explanation of a concept.

Close relationships between agriculture and many areas of human activity determine countless interlinkages with global issues of natural environment protection, human population increase, food supply, industry and world trade. This broad context promotes different perceptions of sustainable agriculture by different interest groups. Profitable diversification away from overproduction of basic commodities and satisfaction of environmental pressure groups are major preoccupations in developed countries. Elsewhere the main concerns is to maintain a trend of increasing production: food security with a future dimension. Achieving this depends essentially on protecting the agricultural resource base. Inputs and input substitution are important co-related issues but the core of sustainability is the avoidance of any attrition of the potential for future production; this demands that we guard soil, water sources, grazing lands and gene pools against loss and degradation. Though superficially biophysical or technical in nature, most problems of resource degradation and eroding potential are rooted in economic, social and political issues; few such problems will be solved unless the primacy of these issues is recognized and addressed. Sustainable agriculture will likely remain elusive until governments and other agencies accept it as arising only as the outcome of a synthesis of strategies on population, employment, economic planning, technical research and national investment.

Agriculture↗
PubMed1992

Polyinosinic-polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose in combination with interleukin 2 in patients with cancer: clinical and immunological effects.

We have performed a phase IB study of polyinosinic-polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose (poly-ICLC) in combination with interleukin 2 (IL-2) in 25 patients with a variety of cancers. Patients received weekly or biweekly poly-ICLC by i.m. injection, at doses ranging from 0.01 to 1.0 mg/m2, for 1 month. This was followed by 2 months of outpatient therapy with biweekly i.m. poly-ICLC in combination with IL-2 (3 x 10(6) units/m2) given i.v. by 24-h continuous infusion twice weekly, using a portable infusion pump. No objective tumor responses were observed. Toxicity was moderate at all poly-ICLC doses tested and increased only slightly following the addition of IL-2. No increases in peripheral blood natural killer (NK) activity were observed after treatment with poly-ICLC alone. However, high dose poly-ICLC (greater than or equal to 0.3 mg/m2) in combination with IL-2 resulted in NK activity greater than that seen using the same dose of IL-2 in combination with lower poly-ICLC doses. Increases in the number and percentage of CD56+ cells were evident only after initiation of IL-2 therapy and were unaffected by the poly-ICLC dose. In the majority of patients, these increases were preferentially associated with the subset of CD56+ cells coexpressing CD8, while the CD56+/CD16+ population was elevated to a lesser extent. Moderate increases in serum neopterin levels and 2',5'-oligoadenylate synthetase activity in peripheral blood mononuclear cells were noted at 72 h following initial treatment with 1.0 mg/m2 poly-ICLC. No induction of alpha or gamma interferon was detected. This study shows that the addition of poly-ICLC to a well tolerated IL-2 regimen can significantly enhance NK activity. Poly-ICLC can be used to enhance IL-2-induced NK lytic activity without increases in the dose and, therefore, the toxicity of IL-2 treatment.

Antigens, CD↗
PubMed1991

Molecular epidemiology of Haemophilus influenzae within families in Santiago, Chile.

Thirty-six consecutive patients with invasive Haemophilus influenzae type b (Hib) infections at Roberto del Rio Children's Hospital, Santiago, Chile, were enrolled in a prospective study. Throat cultures were obtained from household contacts of each index case, adjacent neighbors, and matched community control households. Colonization rates for H. influenzae were comparable among groups; however, among household contacts 18% of colonizing isolates were Hib, compared with 2% and 3% among neighbor and community controls. When selected isolates were evaluated further by outer membrane protein (OMP) profiles and multilocus enzyme electrophoresis, only one of the four Hib isolates from household members matched the corresponding index case isolate. One serologically nontypeable isolate from a household contact had an OMP profile and electrophoretic type identical to that of the corresponding Hib index case isolate; hybridization studies with a 9-kb capsular gene probe showed a profile consistent with a capsule-deficient mutant. Hib strains were isolated more frequently from household contacts than from control persons living in Santiago, but colonizing Hib strains were often unrelated to the index case strain.

Bacterial Outer Membrane Proteins↗