Search PubMed⌕ Search

Biomedical subjects

R G Dent

Publications and source records attributed to R G Dent.

At least 19 recordsLinked to original sources
PubMed1999

The effects of time delay and temperature on capillary blood gas measurements.

Monitoring of blood gas measurements is an important part of the assessment of patients with chronic lung disease. Increasingly, this is being done in the patients' homes by specialist nurses. This makes it important to know the effect of time delay and storage temperature on the reliability of capillary blood gas analysis results. In this study, the effect of a delay of 1 and 2 h and of storage at both room temperature and in ice, on blood stored in glass capillary tubes was investigated. Samples, initially taken from the earlobes, were transferred to glass capillary tubes and used to provide duplicate initial samples for immediate analysis, and then single samples at 1 and 2 h stored at room temperature or in ice. The duplicate baseline measurements showed good reproducibility. There was a small, but statistically significant, increase in PCO2 when samples were stored in capillaries at room temperature, or in ice, both at 1 and 2 h. Small changes in PO2 were not statistically significant, either in ice or at room temperature. None of the changes was considered to be sufficient to be of clinical significance, thus supporting the use of capillary blood sampling even when there might be a delay of 1-2 h and transport is at room temperature, as might be the case when taking domiciliary samples.

Blood Preservation↗
PubMed1989

Nedocromil sodium in adults with asthma dependent on inhaled corticosteroids: a double blind, placebo controlled study.

Eighty nine adults with asthma who were receiving inhaled corticosteroid and bronchodilator treatment took part in a double blind, randomised, placebo controlled trial of nedocromil sodium, 4 mg four times daily by inhalation. During a run in period of two to four weeks corticosteroid treatment was reduced when possible to produce a comparable level of symptoms across the trial population. The test treatment was then taken for four weeks, with the severity of asthma recorded daily by patients and assessed at two weekly hospital visits. There was an improvement in symptoms in the patients taking nedocromil sodium by comparison with those having the placebo, the differences being significant for diary card PEF readings, asthma symptom scores, and bronchodilator usage at night. The mean difference between the two groups was 18 l/min for PEF, 0.42 for daytime asthma score, and 1.73 puffs in 24 hours for bronchodilator usage. These results suggest that asthmatic patients who require inhaled steroids show better control of their asthma with the addition of nedocromil sodium than of placebo over a four week period after reduction of the dosage of their inhaled steroids.

Adolescent↗
PubMed1984

Thin-walled ring shadows in early pulmonary sarcoidosis.

The appearance of ring shadows on the chest radiograph of patients with sarcoidosis is usually associated with generalised, irreversible pulmonary fibrosis. We report three patients in whom thin-walled ring shadows appeared early in the disease. These ring shadows occurred in areas of pre-existing lung shadowing and in two patients they disappeared with corticosteroid therapy over a period of 1-2 years. We postulate that these early sarcoid ring shadows may be caused by a combination of central necrosis of areas of coalescent granulomas and a check-valve mechanism beyond partial obstruction of airways by endobronchial sarcoidosis.

Adult↗
PubMed1983

Left atrial ball valve thrombus. Treatable cause of clinical deterioration in a patient with mitral stenosis.

A 74 year old woman with mixed mitral valve disease presented with episodes of loss of consciousness and fainting. The attacks were noted to be closely related to posture, especially crouching, and this, with the clinical finding that the radial pulse disappeared before she lost consciousness, suggested the diagnosis of a ball valve thrombus. Cardiac catheterisation confirmed the diagnosis but was followed by a fall in blood pressure necessitating emergency surgery. The only position in which the circulation could be maintained was the right lateral, with steep head down tilt, and left femoro-femoral cardiopulmonary bypass had to be established in this position. Operation confirmed the presence of a ball valve thrombus and the patient recovered uneventfully.

Aged↗
PubMed1983

Pulmonary involvement in angio-immunoblastic lymphadenopathy.

Two patients are described who complained of dyspnoea and systemic symptoms. They were found to have angio-immunoblastic lymphadenopathy with extensive pulmonary involvement. In both cases, high dose corticosteroid therapy led to relief of symptoms and clearing of the diffuse radiographic shadowing seen in both lung fields.

Aged↗
PubMed1982

In vitro monocyte maturation in squamous-cell carcinoma of the lung: influence of humoral factors.

A previously described defect of in vitro monocyte maturation in patients with squamous-cell carcinoma of the lung (SCC) has been investigated further. The maturation of patients' monocytes in pooled normal human serum was significantly better than in autologous serum. Conversely, the maturation of normal control monocytes was significantly depressed in patients' serum. The defect has been shown to be due to the presence of an inhibitory factor, rather than the lack of a necessary component in the patients' serum. Artificially aggregated gamma-globulin inhibited monocyte maturation in vitro, but the presence of immune complexes in the serum of many patients with SCC did not correlate well with the depression of in vitro maturation of monocytes from the same patient. Similarly, pregnancy-associated alpha 2-glycoprotein, in increased amounts in the serum of patients with SCC, showed no correlation with monocyte maturation. The addition of soluble extracts of tumour, but not of surrounding normal lung tissue significantly inhibited monocyte maturation. The results suggest that the defective monocyte maturation in patients with SCC is at least in part due to serum inhibitory factors, which are likely to be a heterogeneous group.

Antigen-Antibody Complex↗
PubMed1982

Extraction of light filth from rice flours, extruded rice products, and rice paper: collaborative study.

Two new methods were developed for the extraction of rodent hairs and insect fragments from rice products: one for rice flour and one for extruded rice products and rice paper. A 100 g sample of rice flour was extracted with mineral oil-40% isopropanol, followed by a water phase as needed for additional cycles. For extruded rice products and rice paper, a 225 g sample of each was initially extracted as above, followed by a single extraction with mineral oil-20% isopropanol. Both methods used an acid hydrolysis pretreatment followed by wet sieving and a percolator extraction. Average rodent hair recoveries were 77.8% for rice flour and 82.2% for extruded rice products and rice paper. Average insect fragment recoveries were 89.6% for rice flour and 91.9% for extruded rice products and rice paper. Both methods were adopted official first action.

Animals↗
PubMed1982

Defatting technique for two ground spices using simple reflux apparatus: collaborative study.

A solvent defatting technique was tested for 2 spices which require the same extraction process but different defatting agents. For turmeric, which uses isopropanol as the defatting agent, recoveries of rodent hair and insect fragments were not significantly different from those in the original collaborative study, and this technique is recommended as an alternative to AOAC method 44.122(a). However, for oregano, which uses chloroform as the defatting agent, recoveries of insect fragments were significantly lower by the reflux method. An alternative chloroform pretreatment for oregano, therefore, is not recommended for AOAC 44.122(b). It is suggested that reflux action defatting techniques be considered during the developmental stages of new methods. The technique has been adopted official first action for turmeric.

Animals↗
PubMed1981

In vitro monocyte maturation in squamous carcinoma of the lung.

Maturation of monocytes into macrophages in vitro has been assayed by a quantitative microtitre assay in patients with squamous-cell carcinoma of the lung. Monocyte maturation in autologous serum was significantly depressed in patients with both limited and extensive disease compared with normal controls, patients with chronic obstructive airways disease and controls matched for age, sex, smoking history, respiratory function and the presence of infection. Maturation of monocytes from patients with terminal non-malignant disease was depressed, though not to the same extent as in those with extensive malignancy. Monocytes from relatives of patients with squamous-cell carcinoma of the lung matured normally. In 10 patients with limited disease, in vitro monocyte maturation was repeated 6-12 weeks after operation, and was found to relate to prognosis.

Adolescent↗
PubMed1981

In vitro monocyte maturation as a prediction of survival in squamous cell carcinoma of the lung.

In vitro monocyte maturation was studied in patients with squamous cell carcinoma of the lung--limited to the ipsilateral hemithorax in 30 and more extensive in 40. The patients were studied prospectively and initial monocyte maturation was correlated with survival. Monocyte maturation in patients with limited disease before treatment ranged from 3.1 to 57.6% with a median value of 21.4%. The survival of those patients in whom monocyte maturation was less than the normal range (less than 30.4%) was significantly shorter than the survival in those with normal maturation ( p less than 0.05). Four of the five patients whose initial maturation was less than 10% proved to be inoperable at surgery. Patients with extensive disease had monocyte maturation ranging from 2.4 to 52.9% with a median value of 13.2%, significantly lower than in those with limited disease (p less than 0.025). Patients with extensive disease and low monocyte maturation survived a significantly shorter time than those with normal maturation ( p less than 0.005). The depression of monocyte development may explain the finding of negative delayed hypersensitivity skin reactions in many patients with lung carcinoma and may prove useful as an index of prognosis.

Aged↗
PubMed1981

Extraction and thrips and other whole or equivalent insects from frozen blackberries and raspberries: collaborative study.

A method was developed for the extraction of thrips and other whole or equivalent insects from frozen blackberries and raspberries. The method consisted of a thawing and drained weight step, followed by acid maceration. Berries were wet-sieved over a No. 25 sieve nested in a No. 80 sieve. The berry tissue retained on the No. 80 sieve was dehydrated with isopropanol and then treated with chloroform. The chloroform was stripped from the residue with isopropanol. The berry residue was extracted with light mineral oil from a 40% isopropanol-Tween 80-Na4EDTA mixture. The collaborative study was successfully completed with 83.3% average recoveries of thrips and 19.2% coefficient of variation. The method has been adopted official first action.

Food Contamination↗
PubMed1981

Defective activation of the alternative pathway of complement in two brothers with ataxia-telangiectasia.

Two brothers with ataxia-telangiectasia and recurrent respiratory tract infections are presented. Immunological investigations showed normal immunoglobulin levels (except for the absence of IgA in one child) with absence of haemagglutination inhibiting antibody response to inactivated influenza virus vaccine, normal total lymphocyte counts with decreased T cell numbers, absence of delayed hypersensitivity skin reaction to PPD, in vitro unresponsiveness of T lymphocytes to PHA with presence of a serum inhibitor able to depress normal lymphocyte transformation, and normal phagocytosis and killing of Staph. aureus by peripheral blood polymorphonuclear leucocytes. Complete complement screening revealed a non-functioning alternative pathway in both brothers. The presence of normal factor B lytic activity after isoelectrofocusing the serum and inhibition of the lytic activity of purified components with the patients' serum raised the possibility of a serum inhibitor. The nature of this was not elucidated but it may be one of the reasons why patients with ataxia-telangiectasia have an increased incidence of infections.

Ataxia Telangiectasia↗
PubMed1980

Extraction of light filth from barley, oatmeal, and mixed dry infant cereals: collaborative study.

A new method has been developed for the extraction of light filth from oatmeal, barley, and mixed dry infant cereals which involves HCl digestion followed by wet sieving. The residue is defatted in a paper cup, using isopropanol, and transferred to a 2 L Wildman trap flask with 40% isopropanol. Filth elements are extracted with light mineral oil. Interlaboratory studies resulted in 92 and 86% average recoveries of rodent hairs and insect fragments, respectively. The proposed method has been adopted as official first action.

Edible Grain↗
PubMed1980

Extraction of light filth from ground allspice: collaborative study.

The present official AOAC method (44.120(a)(b), 13th Ed.) for extracting light filth from ground allspice uses flammable solvents and gives poor filth recoveries. An improved method has been developed which uses a single pretreatment with 40% isopropanol and hydrochloric acid followed by wet sieving. After deaeration by boiling, the light filth is extracted from 40% isopropanol-Tween 80-tetrasodium EDTA with light mineral oil. Reports from all 6 collaborators showed that the proposed method resulted in 90 and 89% average recoveries of rodent hairs and insect fragments, respectively. The proposed method is recommended for adoption as official first action to replace AOAC (44.120(a)(b)) for allspice.

Condiments↗