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Biomedical subjects

J L Thomas

Publications and source records attributed to J L Thomas.

At least 145 records · Page 8Linked to original sources
PubMed1982

Effect of body temperature on ventilatory control in the alligator.

Pulmonary ventilation and arterial blood acid-base balance were measured in six unanesthetized alligators, Alligator mississipiensis, at 15, 25, and 35 degree C. The animals exhibited pronounced ventilatory responses to hypercapnia at all temperatures studied. Arterial PCO2 increased and pH decreased with increases in body temperature during both normocapnia and hypercapnia. The fractional dissociation of imidazole (alpha Pr) remained constant with changes in body temperature during normocapnia, but increased with temperature during hypercapnia. Ventilatory sensitivity, defined as delta (VE/VO2/delta (alpha Pr), was independent of body temperature. We conclude that the control of breathing in the alligator is a physiological defense of alpha Pr and that ventilatory responses occur following nontemperature-induced changes in blood acid-base balance, which tend to return alpha Pr to a normal value.

Acid-Base Equilibrium↗
PubMed1982

Limited CT studies in monitoring treatment of lymphoma.

One hundred and two follow-up CT studies in 50 patients with a diagnosis of lymphoma were reviewed to determine the efficacy of limited CT studies for determining therapy. The overall correlation between the limited CT study and the complete CT study was 98%. No mixed responses occurred in 102 cases. Two patients, both with diffuse histocytic lymphoma treated by chemotherapy, showed progression of disease outside a stable tumor bed not detected by a limited CT study. The economic implications, technique, and limitations of limited CT studies are presented.

Follow-Up Studies↗
PubMed1982

[Diffuse nonautoimmune hyperthyroidism].

Diffuse non auto-immune hyperthyroidism is a rare entity, classically restricted to cases with hypersecretion of TSH, hCG or related molecule and to a few reports of proven paraneoplastic origin. The authors try to individualize another type of diffuse hyperthyroidism, previously considered to belong to Graves' disease, but without any sign of disimmunity. They present a familial form with several hyperthyroidic patients who showed neither change in humoral immunity nor immunological abnormality within the thyroid gland, even in those that were operated upon without prior antithyroid medication. Similar findings occurred within several series of hyperthyroid glands separately studied by the authors, using different techniques: histomorphometric quantification of lymphocytic infiltration, immunofluorescence in the search of IgG, IgA, IgM, C1 q, C3 and C9 fractions, or T-lymphocyte subsets. These techniques generally tend to yield positive results, that agree with an auto-immune pathogenesis, but totally negative findings do occur. This type of diffuse hyperthyroidism should be delineated from the common auto-immune type, and might be called toxic hyperplasia.

Antibody Formation↗
PubMed1982

Prognostic significance of the development of left bundle conduction defects following aortic valve replacement.

The association of intraventricular conduction defects and aortic valvular disease is widely recognized. This study was undertaken to evaluate the effects on survival of left bundle conduction defects (LBCDs) as a consequence of aortic valve replacement. A total of 133 patients were followed between 1 and 70 months after operation, with a mean follow-up of 32.1 months. The incidence of intraoperative LBCDs was 31.6% or 42 patients. There were 13 deaths in the group of 42 patients with LBCDs compared to eight deaths in the group of 91 patients without such abnormalities (p less than 0.01). Sudden death occurred in five of 42 patients with postoperative LBCDs and two of 91 patients with normal intraventricular conduction (p less than 0.025). The survival rate in these patients with significant aortic stenosis and normal intraventricular conduction was 89.9%, whereas if LBCD had occurred after operation, the survival rate was 65.7% (p less than 0.005). If the LBCD was accompanied by a left axis deviation, the survival rate was 21.7%. Sudden death may be due either to a tachyarrhythmia or perhaps to progression from LBCD to complete heart block or trifascicular block. It is important that this group of patients be monitored closely after operation. There may be an indication to insert prophylactic permanent pacemakers in this group.

Aortic Valve↗
PubMed1981

Use of intravenous liposoluble contrast material for the examination of the liver and spleen in lymphoma.

An experimental contrast material has been developed that, after intravenous injection, selectively opacifies the spleen and liver on computed tomography (CT). The contrast material contains iodinated ester of poppy seed oil in an emulsified form. Clinical trials were recently initiated to test the value of this contrast agent in Hodgkin's and non-Hodgkin's lymphomas. We present here two of our initial patients in whom we found lesions in the spleen or liver following the infusion of the experimental contrast material that were not visualized on the precontrast and urographic contrast material enhanced CT scans.

Adult↗
PubMed1981

Ultrasonic findings in silicone-augmented breasts.

The sonographic and clinical findings in four patients with silicone-augmented breasts are presented. The ultrasonographic differences between breasts with silicone injections and breasts with silicone prosthesis are emphasized. Breast sonography may play a role in evaluation of silicone-augmented breasts. Awareness of this diagnostic procedure may help in evaluating these patients.

Adult↗
PubMed1981

The extremity soft-tissue lesion: a comparative study of ultrasound, computed tomography, and xeroradiography.

Twenty-five extremity soft-tissue lesions were evaluated by ultrasound (US), computed tomography (CT), and xeroradiography (XR). The lesion was detected by CT in 20 of 25 cases. In five cases, a soft-tissue tumor was not identified by CT due to small lesion size, isodensity, or the inability to distinguish scar tissue from recurrent tumor. Of the three modalities, the vascular bundle was most reliably defined by CT. In 20 of 25 cases, the lesion was detected by XR, but the size was accurately determined in only 13 cases.

Adolescent↗
PubMed1981

Pitfalls in the diagnosis of hepatic cysts by computed tomography.

Seven patients with computed tomographic (CT) evidence of cystic hepatic lesions are presented. In these cases, CT could not reliably distinguish benign hepatic cysts from other intrahepatic and extrahepatic cystic lesions. The attenuation coefficients of simple cysts and inflammatory or neoplastic lesions were similar, and smooth margins occurred in all three of these conditions. It was not possible to visualize and differentiate lesion walls from the surrounding normal hepatic parenchyma in some cases. It is concluded that the specificity of CT in the differentiation of benign cysts and other lesions is lower in the liver than it is in other areas, such as the kidney, and that in cases of diagnostic uncertainty, biopsy should be performed.

Adult↗
PubMed1981

Neoplastic-induced renal vein enlargement: sonographic detection.

Five patients with sonographic evidence of a dilated renal vein are described. The etiology of the dilated renal vein was tumor thrombus in two patients, neoplastic arteriovenous shunting in two, and portal systemic shunting into the left renal vein in one. Tumor thrombus had echogenic enlargement of the renal vein, whereas anechoic enlargement of the renal vein was secondary to increased blood flow within the renal vein. Portorenal shunting can be differentiated from a neoplastic renal arteriovenous fistula by the presence of thrombus within the portal system and the absence of a renal mass. Pitfalls in the diagnosis of renal vein enlargement are discussed.

Adenocarcinoma↗
PubMed1981

An initial experience with post-data processing in hepatic sonography.

Sonographic image manipulation became a possibility with the advent of digital equipment. Depending on the manufacturer, this manipulation may be called pre-data processing, post-data processing, or both. It involves changing the normal assigned gray scale curve to accentuate defined decibel ranges. Sixty consecutive patients were examined who had technically adequate hepatic sonograms using the normal linear gray scale range and post-data processing (PDP). Sonograms were considered normal in 32 patients, while 28 were believed abnormal. In 10 of the 28 abnormal scans, hepatic metastases were better visualized with post-data processing (one false-positive). These were patients in whom there was a minimal echogenic difference between the surrounding normal liver and the lesion. However, in no case was a lesion seen after post-data processing that was not recognizable on the linear gray scale scan. In the other 18 abnormal scans (one false-positive study), the echogenic difference between the lesion and the liver was large enough that PDP was not helpful. The possible pitfalls in the use of PDP, such as poor technique, are discussed and demonstrated. Improvement in hepatic sonographic sensitivity will require more fundamental improvement of equipment than provided by post-data processing.

Computers↗
PubMed1981

Therapeutically infarcted tumors: ct findings.

The CT findings in 14 patients who underwent hepatic or renal embolizations are presented. In 11 patients who had postinfarction CT studies, linear, branching air collections were noted within the embolized tumor. In two patients the amount of air increased on later CT studies. This configuration of air suggested an abscess, but in no case was an abscess encountered. This air was located distal to the high density embolization material in four cases. In four cases the infarcted organ appeared denser due to "trapped contrast." The seven embolized livers did not change in size on follow-up examinations, while three renal tumors demonstrated variable size changes after embolization.

Air↗
PubMed1981

Sonography of gynecomastia.

The sonographic findings in four patients with gynecomastia are presented. The sonographic appearance is correlated with previously described pathologic and x-ray mammographic findings. Sonographically, early, focal gynecomastia appears as a triangular, hypoechoic mass in the retroareolar area. As gynecomastia become diffuse, it results in a hyperechoic increase in the glandular parenchyma. Awareness of the various etiologies and variations in appearance is important for the sonographic diagnosis of gynecomastia.

Adult↗
PubMed1981

Staging of testicular carcinoma: comparison of CT and lymphangiography.

Clinical staging by computed tomography (CT) and lymphangiography was compared in 27 patients with pathologically staged testicular carcinoma, primarily nonseminomatous tumors. The overall accuracy of CT was 89%; the sensitivity, 90%; and the specificity, 83%. The accuracy of lymphangiography for detecting nodal abnormalities was 70%; the sensitivity, 71%; and the specificity, 67%. In 48% of cases, CT provided better delineation of tumor margins. Also, CT detected retrocrural nodal enlargement in 14% of patients and hepatic metastasis in 5%. The usefulness and limitations of both methods are discussed along with their clinical implications.

Adolescent↗