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Biomedical subjects

A G Wilson

Publications and source records attributed to A G Wilson.

At least 91 records · Page 5Linked to original sources
PubMed1990

Linear opacities as a feature of pneumocystis pneumonia.

Linear opacities are generally regarded as uncommon in pneumocystis pneumonia. The authors' experience suggests this is not so, and that such opacities may have diagnostic value. Chest radiographs of 22 episodes of uncomplicated pneumocystis pneumonia were reviewed and linear opacities were present in nine episodes (41%). Similar opacities were present in 11 out of 121 cases of other pneumonias (9%). Characteristically the opacities are related to the acute illness, usually one to three in number, predominantly basal, 1-4 cm long and less than 2 mm thick. Other radiographic signs of pneumocystis pneumonia were present in all cases. The pathogenesis of these linear opacities is uncertain, but it is possible that they result from areas of sub-segmental atelectasis. The frequency of such linear opacities is much greater in pneumocystis pneumonia (four times) than in other pneumonias and they therefore have some diagnostic value.

Adult↗
PubMed1989

Lack of in vivo DNA binding of mercaptobenzothiazole to selected tissues of the rat.

In this study, the in vivo binding of 14C-labelled 2-mercaptobenzothiazole (MBT) to DNA was investigated. Male and female Fischer 344 rats were gavaged with 375 mg MBT/kg body weight and killed 8 hours later. DNA was extracted from the liver, adrenal glands, pituitary gland, pancreas, and bone marrow and the amount of radioactivity associated with the DNA was determined. Results from this study indicate that MBT does not significantly bind to DNA from any of the tissues examined. CBI values for liver for the 3 methods of purification were -1-3 which are on the low end of the covalent binding index. The CBI values for the other tissues were always less than 1. Other chemicals with similar CBI values include estrone and diethylstilbesterol. Strong hepatocarcinogens such as dimethylnitrosamine and aflatoxin have CBI values ranging from 6000 to greater than 20000.

Adrenal Glands↗
PubMed1989

The posteroanterior chest radiograph in depressed sternum.

The posteroanterior and lateral chest radiographs of 72 consecutive patients with sternal depression, together with 72 age- and sex-matched controls, have been reviewed. We assessed size and position of the cardiac silhouette, mediastinal contour, radio-opacity in the right lower zone and rib configuration. The degree of depression was determined from the lateral radiograph. The most significant signs of sternal depression on the posteroanterior chest radiograph are a straight left heart border, displacement of the cardiac silhouette to the left and an indistinct right heart border. These three signs have a high specificity for sternal depression and are significantly more commonly seen with increasing severity of depression. The presence of any three, or of more than three, of the described signs was 95.5% specific. However, despite this high specificity, the sensitivity and positive predictive value even for a combination of signs are low. Sternal depression is a relatively common chest deformity and the radiologist should be aware of the changes on the posteroanterior chest radiograph to avoid pitfalls in diagnosis.

Adult↗
PubMed1989

Physiological pharmacokinetic model of hexachlorobenzene in the rat.

A physiologically based pharmacokinetic model was developed to describe the distribution of hexachlorobenzene (HCB) in the rat after oral administration or injection. The model was based on flow-limited blood perfusion of HCB to tissues and organs of the body. A set of simultaneous differential equations were solved for the different tissue concentrations as a functions of time. The model allowed for elimination of HCB by excretion. The model also allowed for differential growth of various tissues over the course of an experiment. Computer simulations using the model indicated that growth of animals during the course of dosing experiments can greatly increase the apparent half-life of HCB.

Animals↗
PubMed1989

The value of transoesophageal ultrasonography in the management of a mediastinal foregut cyst.

Mediastinal foregut cysts account for approximately 10% of primary mediastinal masses. The differentiation of these cysts from other mediastinal masses is important, especially if a policy of aspiration and observation of cysts is adopted. Computed tomography (CT) is generally regarded as the definitive imaging modality in these cases, but it may occasionally fail to identify the cystic nature of the mass. We report a case in which transoesophageal ultrasound contributed to the diagnosis and demonstrated features of the cyst contents that were not visible on CT.

Esophagus↗
PubMed1989

Optimization of cryopreservation procedures for rat and human hepatocytes.

1. Rat hepatocytes were cryopreserved using a number of procedures and the viability, attachment, and metabolic activity of the cryopreserved cells were compared to freshly isolated hepatocytes. Several cryopreservation agents (dimethylsulphoxide [DMSO], glycerol, polyvinylpyrrolidone [PVP], dextrans), and combinations of these agents, were examined. Other variables tested included the freezing rate, thawing rate, and the concentration of serum in the freezing medium. 2. Recovery of viable attached cells was optimal using DMSO at concentrations of 10% or higher, a slow stepwise cooling procedure, and a quick thaw. The concentration of serum in the freezing medium (0% to 90%) did not affect cryopreservation results. Using this procedure the recovery of viable hepatocytes was 70%. 3. Levels of hepatocyte ethoxycoumarin-O-deethylase (ECOD) activity did not change following cryopreservation. The rate of decline of ECOD activity with time in culture was similar in freshly isolated and cryopreserved hepatocytes. 4. Hepatocytes isolated from three human livers were cryopreserved and recovered with viabilities similar to those obtained with the rat. A preliminary experiment also showed no loss of metabolic activity in human hepatocytes following cryopreservation.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1988

Promutagen activation by freshly isolated and cryopreserved rat hepatocytes.

The metabolic activation of promutagens by freshly isolated and cryopreserved rat hepatocytes was compared using the Chinese hamster ovary/hypoxanthine-guanine phosphoribosyltransferase assay (CHO/HGPRT). Cryopreserved rat hepatocytes were equivalent to freshly isolated hepatocytes in their ability to metabolize dimethylbenz(a)anthracene (DMBA) and dimethylnitrosamine (DMN) to active mutagens. Similar dose-response curves were observed using either freshly isolated or cryopreserved hepatocytes as activating systems after treatment with DMBA (0.1-1 micrograms/ml) and DMN (0.075-0.6 mg/ml). Our results suggest that cryopreserved hepatocytes are similar to freshly isolated hepatocytes as an experimental system for studies on promutagen activation.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1987

The chest radiograph in whooping cough.

The chest radiographs of 238 patients admitted to hospital with acute whooping cough are reviewed. Radiographic abnormalities were detected in 63 (26%) patients; pulmonary consolidation was seen in 50 (21%) patients, collapse in nine (4%) and lymphadenopathy in 22 (9%). The most common type of consolidation was peribronchial (72%). Both collapse and consolidation were commoner on the right and tended to involve the lower and middle lobes. These abnormalities were more common in those aged 1 year old or more (p less than 0.001) but no other clinical feature was found to predict those patients with an abnormal chest radiograph. Follow-up radiographs demonstrated no significant radiographic sequelae. Comparison with previous series shows a reduced frequency and change in the pattern of radiological abnormalities over the last 20 years.

Child↗
PubMed1987

The interpretation of shadows on the adult chest radiograph.

In this article I consider that part of the interpretation of a chest radiograph that is concerned with abnormal opacities. The recognition of various shadow patterns and their interpretation in terms of gross pathology is central to the approach.

Heart↗
PubMed1986

The radiology of aseptic cavitation in pulmonary infarction.

Eight patients with aseptic cavitation of sterile pulmonary infarcts are described. All except one had left ventricular failure and/or chronic airflow obstruction. Infarcts with cavities were commonly single (75%) and right-sided (69%) and usually followed a sizeable area of consolidation (larger than 4 cm) after about 2 weeks. Of the 62% that could be localised to a segment, all were in the apical or posterior segment of an upper lobe or the apical segment of a lower lobe and the majority (85%) had scalloped inner margins and cross cavity band shadows. At the time of cavitation, 38% had additional features on the chest radiograph that were suggestive of pulmonary embolic disease. A number of cavities developed a tertiary infection and an air-fluid level but the latter feature was non-specific. Aseptic cavitation of a sterile pulmonary infarct should be considered in the differential diagnosis of any cavitating lung lesion, particularly if it shows the above features.

Aged↗
PubMed1985

Sarcoidosis in Caucasians, Blacks and Asians in London.

The incidence and clinical features of sarcoidosis were studied in a retrospective survey of 156 patients attending two South London hospitals between 1969 and 1982. Sixty-eight patients were Caucasian, 59 were Black West Indian or African immigrants and 29 were immigrants racially derived from Indo-Pakistan (Asians). The annual incidence of sarcoidosis in the local community in 1977-78 was 19.8 per 10(5) for Blacks and 16.8 per 10(5) for Asians compared with 1.5 per 10(5) for Caucasians. Erythema nodosum was a more common presenting feature in Caucasians than in Blacks (P less than 0.001) or Asians (P less than 0.05). Blacks developed sarcoidosis at a later age than Caucasians (P less than 0.05) and were less likely to present as a chance finding on a chest radiograph (P less than 0.05). They had more widespread extrathoracic disease than Caucasians (P less than 0.001) and were more commonly treated with corticosteroids (P less than 0.001). In the Asians there was a male predominance compared with Caucasians (P less than 0.01). Asians also had more extrathoracic sarcoidosis than Caucasians (P less than 0.001) and more of them were treated with corticosteroids (P less than 0.05). A stage 2 chest radiograph at presentation (P less than 0.05) and skin sarcoidosis (P less than 0.05) were less common in Asians than in Blacks, but otherwise there were no significant differences between the two groups. In this study the incidence of sarcoidosis in Asians approached that in Blacks, while the clinical features were intermediate in severity between Blacks and Caucasians. In both Blacks and Asians the disease was more common, more severe and more extensive than in Caucasians.

Adrenal Cortex Hormones↗