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Biomedical subjects

W F Whimster

Publications and source records attributed to W F Whimster.

17 recordsLinked to original sources
PubMed1992

Cardiodynamic effects of dopamine and dobutamine.

On 11 patients undergoing coronary surgery, at the end of the surgical intervention, the inotropic responses to 0.4 and 0.8 microgram x kg-1 x min-1 dopamine and dobutamine given via the aorto-coronary bypass directly into the coronary artery were compared. These dosages correspond to ones 10 times greater applied intravenously. The measurements were made using needle force probes which were implanted into the myocardial offstream area in the left ventricular wall. Bypass flow was measured simultaneously by an electromagnetic flow probe. There is a significant increase in coronary bypass flow induced by both rates of 0.4 and 0.8 microgram x kg-1 x min-1 dobutamine, but there was no significant effect on bypass flow induced by dopamine. Developed myocardial force is raised more by dobutamine medication than by dopamine. However, the rate of contraction increases significantly and relaxation is significantly accelerated by dopamine at both dosages. A significant increase in rate of contraction and relaxation was only induced by the higher dosage of 0.8 microgram x kg-1 x min-1 dobutamine.

Aged↗
PubMed1991

Kinetic aspects of Ki-67 antigen expression in a normal cell line.

Using a normal cell line derived from a human fetus, the disappearance and reappearance of the Ki-67-reactive antigen following modification of the cell cycle was observed and estimated immunohistologically. It was found that G1/G0 arrest induced by serum deprivation resulted in loss of the antigen in 24 h in all but a few (usually less than 10%) of cells. Return to normal medium and resumption of growth was accompanied by reappearance in 30 h. When entry into S-phase was prevented by desferrioxamine, reappearance of the antigen still occurred but only lasted for about 24 h. Inhibition of protein synthesis with cycloheximide also caused fading and eventual loss of immunostaining. In view of the ease with which this antigen becomes undetectable with cessation of protein synthesis and interruption of the cell cycle, we agree with those who advise caution in the use of Ki-67 to measure growth fraction in changeable cell populations such as tumours.

Blood↗
PubMed1991

Distribution and estimation of nucleolar organizer regions in various human lung tumours.

A quantitative study of nucleolar organizer regions in human lung carcinomas was carried out on routinely processed paraffin embedded tissue sections. We examined 104 lung carcinomas including 38 squamous cell carcinomas, 36 adenocarcinomas, 18 large cell anaplastic carcinomas, 6 small cell carcinomas and 6 carcinoids. No significant differences were found in mean number of NORs between squamous, adenocarcinoma and undifferentiated carcinomas including large cell and small cell carcinomas. Carcinoids had comparatively lower means except for one typical carcinoid. Considering the high incidence of overlap between ranges of NOR counts in these groups of tumours and in agreement with the only other study of lung tumours (which comprised only carcinoids and small cell carcinomas), we conclude that this technique cannot be reliably used to discriminate between various histologic types of lung cancers. However, long term follow up of these patients is needed to establish the value of the AgNOR technique for prognostic guidance.

Adenocarcinoma↗
PubMed1990

Proportion of necrosis in transplanted murine adenocarcinomas and its relationship to tumor growth.

Percentage of necrosis has been measured in 30 murine adenocarcinoma transplants of known volume. It was found that changes in necrotic proportion during the growth of these particular tumors agree with the concept of a core of necrosis surrounded by a viable shell of constant thickness. This means that viable and necrotic fractions were proportional to the surface area of the tumor, which is consistent with the frequently observed superficial distribution of nutrient-supplying arteries. According to this model a plot of 1n tumor volume versus necrotic fraction is sigmoid and, if tumor growth is directly related to viable fraction, such a plot is not compatible with popular mathematical growth equations. However, the equation of von Bertalanffy gives a reasonable fit to the data here for total tumor growth, suggesting that growth too was proportional to surface area and in accord with a surface-related viable fraction and blood supply. An appropriate physiological explanation is given of necrosis development resulting from a superficial nutrient supply.

Adenocarcinoma↗
PubMed1978

Gold lung.

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Adult↗
PubMed1978

A comparative study of the accuracy of area assessment by point counting for bronchial mucous glands.

The accuracy with which areas of bronchial mucous gland on histological sections may be determined has been investigated with respect to inherent statistical variability in the point counting procedure used, and with respect to variations between the histological stains and observers employed. Very good argeement was obtained between areas determined by point counting and by planimetry. It was shown empirically that for sections of well-defined gland-like structures the accuracy (coefficient of area) of area determination was inversely proportional to the 3/4 power of the mean point count. The constant of proportionality depended on the structure's shape and on the point geometry of the grid used. Using the relationship the count needed to achieve a required accuracy of area determination could be established. It was shown that in general a smaller count was required for a given accuracy than would be the case using randomly dispersed tissue. On histological sections the accuracy of area determination is also dependent upon gland boundary definition, and our experiments showed that a recticulin Alcian Blue stain best defined mucous gland acini, and that a PBS stain gave the most accurate results for whole gland. These experiments also showed that there were small but significant differences in mean areas determined by different observers. The observers were shown to be equally consistent in their judgment of what constituted whole mucous gland and acini, but since they differed over mean counts it is recommended that studies should be designed to use either a single observer or to assign observers randomly among groups. With these considerations point counting can be made an accurate method of area determination for these or similar tissues.

Anthropometry↗
PubMed1977

A difference in the composition of bronchial mucus between smokers and non-smokers.

The ratio of the amount of sulphated to sialic acid mucin (Su/Si) in the mucous glands of the human tracheobronchial tree has been investigated in seven smokers and seven non-smokers. The two mucins were studied in histological sections stained by the high iron diamine/Alcian blue pH 2-5 sequence and assessed by a point-counting method. Su/Si was greater in the smokers than in the non-smokers, who were almost completely distinguished by this ratio. A decrease in the ratio with each generation of branching from the trachea down the inferior lingular bronchial segmental pathway was seen in both the smoking and non-smoking groups. Analysis of the logarithm of Su/Si showed the smoking group means to be 2-3 times that of the non-smokers at each generation, and over both groups the average decrease down successive generations was given by a factor of 0-9.

Aged↗
PubMed1977

Distribution of acid mucus in the bronchial mucous glands.

The percentage area of the bronchial glands taking up the Alcian blue (pH 2-6) stain for acid mucin was obtained from sections from the trachea and from each generation down the inferior lingular axial bronchial pathway in five non-smokers and five cigarette smokers. The mean percentage value for the smokers (59-5%) was significantly less than for the non-smokers (74-4%). The percentage increased between successive generations from the trachea by an average of 6-5. This gradient did not differ significantly between the smoking and non-smoking groups. It was not possible to attribute these differences to any specific mechanism because many interacting variables were involved which could not be measured. Nevertheless the percentage mucin retention or storage provides an introduction to consideration of these variables and their response to cigarette smoke.

Aged↗
PubMed1976

How I subedit.

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Medicine↗
PubMed1976

Necrotizing 'sarcoidal' angiitis and granulomatosis of the lung.

A case of necrotizing sarcoid angiitis and granulomatosis (NSG) presenting as a peripheral lung 'tumour' in a 63-year-old man is recorded, and the clinical and pathological features are compared with those of Liebow's original cases. Resection may be avoided if the diagnosis is made by biopsy as the disease is possibly steroid responsive and the prognosis appears favourable. The aetiology is obscure but an immune disturbance is suspected.

Arteritis↗
PubMed1976

An account of the longitudinal mucosal corrugations of the human tracheo-bronchial tree, with observations on those of some animals.

A description is given of the distribution of the longitudinal mucosal corrugations in the human tracheo-bronchial tree. It has been shown that they are made up of elastic tissue in a collagen matrix, and that the elastic fibres continue into the smallest bronchioles beyond where the corrugations are no longer visible. An examination has also been made of the tracheo-bronchial trees of the hen, rat, raccoon, pig, sheep, llama and tiger. Corrugations are present in all these animals, except the hen and the raccoon, and they have been compared and contrasted with the condition in Man. The functional significance of these corrugations remains unknown, but, they could be important in equalizing tension in the tracheo-bronchial tree during inspiration, as well as in providing elastic recoil during expiration.

Adult↗