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C Smith

Publications and source records attributed to C Smith.

At least 937 records · Page 52Linked to original sources
PubMed1984

Micropipette aspiration of human platelets: influence of microtubules and actin filaments on deformability.

The deformability of human platelets has been evaluated by micropipette aspiration. Control discoid platelets were about ten times as resistant to deformation in the micropipette as red blood cells. Under a constant negative pressure of 10 cm H2O, control platelets developed extension lengths of 0.74 +/- 0.1 micron. Prior treatment with vincristine, colchicine, or low temperature, all of which remove platelet microtubules, was associated with marked increases in lengths of aspirated segments. Taxol or heavy water, which stabilize microtubules, prevented the increased deformability caused by agents that dissolve microtubules. Cytochalasin B, an agent that inhibits assembly of actin microfilaments, also caused an increase in lengths of aspirated segments that could not be prevented by taxol. Vincristine and cytochalasin B, together, caused a greater increase in deformability than either agent alone. These results indicate important roles for microtubules and microfilaments in platelet deformability.

Actins↗
PubMed1984

Roche RIA and Abbott EIA carcinoembryonic antigen assays compared.

We have evaluated Roche Diagnostics' RIA-CEA and Abbott Diagnostics' EIA-CEA methods for precision, normal reference interval, concordance, and correlation of malignant disease with increase in carcinoembryonic antigen (CEA) in plasma. In examining concordance, we used data on 138 patients with primary carcinomas of the breast, colon, lung, or pancreas, each further classified by extent of dissemination. We find the two methods to be comparably precise. The respective upper reference limits of normal for the Roche and Abbott methods were determined to be 5.0 micrograms/L and 4.6 micrograms/L. The regression equation for a log transformation of the 177 data points is y = 0.966x + 0.03, where x = Roche and y = Abbott, with a correlation coefficient of 0.948. According to the criteria we used, the concordance was 78.7%. The largest discordance was observed in widely disseminated disease states and in cancers of the colon and pancreas. Paired data analysis of discordance indicated greater increases in apparent CEA by the Abbott method in most colon cancers with liver involvement; six of the eight discordant pancreatic cancers had higher Roche-CEA values. CEA heterogeneity and the role of the liver in CEA metabolism appear to contribute to the observed differences. We show why the two methods should not be used interchangeably, and that baseline values for CEA must be established for each method.

Breast Neoplasms↗
PubMed1984

The use of immunohistochemical probes in the study of benign and malignant breast disease.

A review is presented of the use of immunohistochemical probes in the study of the cellular pathology of the breast. Using a combination of monoclonal and polyclonal antisera it has been possible to investigate the relationship between myoepithelial cells and basement membrane components in benign breast disease and the disturbance of this relationship in early invasive and infiltrating ductal carcinomas. The use of immunohistochemical techniques at the ultrastructural level provides the methodology for future detailed analyses. The heterogeneous expression of antigenic determinants characteristic of epithelial cells in the normal breast is considered in conjunction with its relevance to the heterogeneity seen in the invasive tumours.

Animals↗
PubMed1984

Xeroradiography of the lateral neck.

Because of its "edge enhancement" technique, xeroradiography provides an improved method for evaluation of the laryngeal cartilages and soft tissue coverings when compared to conventional radiographs. If one becomes familiar with the varied appearances of the normal structures, there is a large amount of information which can be obtained from a single lateral view of the neck which would otherwise be overlooked or misinterpreted. This article is intended to familiarize the reader with the various techniques available to study the structures of the larynx and associated soft tissues. However, much of the emphasis will be on the xeroradiographic appearance of normal structures and abnormal processes in both the adult and the pediatric patient.

Head and Neck Neoplasms↗
PubMed1984

Supracondylar humeral osteotomy for traumatic childhood cubitus varus deformity.

Between 1958 and 1983, 45 corrective supracondylar osteotomies of the humerus were performed for post-traumatic cubitus varus deformity in 43 children. The average follow-up period was two and one-half years. Excellent or good results were obtained in 33 patients. Unsatisfactory results were seen in 12. The operation, though deceptively simple, had a significant complication rate (24%), including neuropraxia, sepsis, and cosmetically unacceptable scarring. After these problems were analyzed, the important points of technique that were noted were a comprehensive preoperative plan and a simple lateral closing wedge osteotomy, leaving the medial cortex intact and ignoring rotational deformity.

Bone Nails↗
PubMed1983

Adrian.

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Adolescent↗
PubMed1983

Preliminary characterisation of inhibitors of DNA polymerase isolated from Xenopus laevis early embryos.

Inhibitors of DNA polymerase have been detected in Xenopus laevis ovary and egg extracts. The characteristics of the inhibitors differ between the two extracts. In ovary preparations, the inhibitor is retained by dialysis tubing and is heat sensitive, whereas in egg extracts it is diffusable and heat stable. In both extracts, the activity co-elutes with DNA polymerase after ion exchange chromatography. Chromatography of ovary extracts renders the inhibitor diffusable and heat stable. Preliminary characterisation of inhibitory activity from eggs shows that the substance is sensitive to pronase digestion and has an approx. 300-500 molecular weight. Kinetic studies demonstrate that the inhibitor is uncompetitive with the DNA template and show mixed inhibitory kinetics with respect to the deoxynucleotides.

Animals↗
PubMed1983

Extragonadal endodermal sinus tumors in children: a review of 24 cases.

Endodermal sinus tumors (EST) are highly malignant lesions with a tendency to recur locally and with a high incidence of metastatic disease at the time of diagnosis. The clinical and radiographic spectra of 24 patients with extragonadal EST are reported. There were 17 females and seven males and the mean age of presentation was 21 months. The primary lesion occurred in the sacrococcygeal region in 16 patients; in the vagina in two patients; in the anterior mediastinum in two patients; and in the bladder, liver, nasopharynx and posterior cranial fossa in one patient each. Computed tomography (CT) is the most accurate study in delineating the extent of primary lesions particularly in the pelvis and head and neck and also for demonstrating metastatic disease in the lungs. Significant improvement in survival rates is obtained with a combination of surgery, chemotherapy and radiotherapy.

Child, Preschool↗
PubMed1983

A pharmaceutical profile of diabetic patients.

Although there have been innumerable studies documenting various aspects of the morbidity caused by diabetes mellitus in the population, very little attention has been paid to patterns of therapeutic management of diabetic patients. The United States Public Health Service Ambulatory Care Data System (USPHS ACDS), a computerized patient information entry and recording system with a complete pharmaceutical record for each patient, was used to compare patterns of pharmaceutical consumption among diabetic patients as opposed to non-diabetic patients in a population of approximately 90,000 individuals. Drug use by diabetics was significantly higher than by non-diabetics. Cardiovascular drug use, in particular, was considerably higher. Substantially higher consumption of anti-lipemic agents, anti-gout drugs, anti-hypertensives, sedatives and tranquilizers was also found in the diabetic population. The higher use of all drugs by diabetics could be partially explained by a demonstrably higher frequency of out-patient visits by diabetics. However this factor alone could not account for very much higher use of certain selective drug groups by the diabetics. In most cases, these selective increases among the diabetics paralleled expected patterns of disease for which those drug groups are prescribed. The investigation of pharmacotherapeutic profiles of the diabetic population adds a new dimension to the epidemiological study of this disease.

Adult↗
PubMed1983

Effect of prosthetic airway splint on the growing trachea.

Airway splints are now used clinically to treat tracheomalacia and may also have a place in the management of tracheal stenosis. These studies in 5 to 7 Kg piglets were designed to assess the effects of prosthetic airway splints on airway growth and to establish their usefulness in the reconstruction of tracheal defects. Three experimental groups were studied: group I (n = 8). Silastic reinforced Marlex mesh or Vicryl mesh prostheses were placed around 75% of the circumference of a 3 cm segment of trachea. Pigs were sacrificed at 4 months (average weight = 78.9 +/- 9.0 Kg) and the cross-sectional area of trachea was measured. Group II (n = 5). The same prostheses were used to replace the tracheal defect created by excising three rings (50% of tracheal circumference). Tracheas were examined grossly and histologically at sacrifice. Group III (n = 5). Same as Group II except tracheal defect covered by strap muscles. Prostheses placed external to them to prevent airway collapse. Group I had 4% to 14% (mean 8%) decrease from normal cross-sectional area of trachea at site of splint. No airway obstruction and no infection was encountered. Group II, severe airway obstruction, granulation tissue, and infection at site of defect was noted. Group III showed no signs of airway obstruction, no infection, and minimal airway narrowing. Re-epithelialization of the muscle surface in contact with airway occurred in all these animals. Silastic reinforced Marlex or Vicryl splints placed around the intact rapidly growing trachea do not significantly limit its growth. In addition, these synthetic materials appear to be well-tolerated when used to reconstruct tracheal defects if placed over well-vascularized tissue such as muscle.

Animals↗