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Biomedical subjects

D C Jackson

Publications and source records attributed to D C Jackson.

At least 145 records · Page 8Linked to original sources

Arteriographic embolization for control of recurrent severe gastric hemorrhage in a 10-yr-old boy.

Severe stress ulceration or stress gastritis may occasionally produce uncontrollable gastric hemorrhage in the pediatric age group. Modern arteriographic techniques utilizing selective embolization to occlude demonstrated bleeding arteries can successfully control such hemorrhage and avoid emergency destructive surgical resection. A 10-yr-old boy, in whom a previous 80% gastric resection failed to control life threatening hemorrhage, is presented, with roentgenographic demonstration of the procedure and the successful control of his gastric bleeding.

Angiography↗

Vessel occlusion with transcatheter electrocoagulation: initial clinical experience.

Transcatheter electrocoagulation (TCEC) was used for vessel occlusion in combination with embolization by Gelfoam and/or Ivalon in six patients in whom other interventional or surgical techniques were considered dangerous or unfeasible. The technique was effective in decreasing or obliterating the blood supply to variously located lesions in all cases. The only complications were small skin burns in one patient and a small ulceration of the upper lip in another.

Adult↗

The role of the radiologist in acute gastrointestinal bleeding.

Angiography is valuable in the diagnostic and therapeutic management of the patient with acute gastrointestinal bleeding. It should be preceded by endoscopy in acute upper gastrointestinal bleeding, but in acute lower gastrointestinal bleeding, angiography is firmly established as the primary diagnostic modality. Although angiography is less useful in chronic gastrointestinal bleeding, it may show the underlying pathologic lesion. Vasonconstrictive and embolic therapeutic angiographic procedures are particularly valuable in the patient with multiple system disease.

Celiac Artery↗

Respiratory control and CO2 conductance: temperature effects in a turtle and a frog.

The respiratory control systems of the predominantly lung-breathing turtle. Pseudemys scripta, and the bimodal breathing frog, Rana catesbeiana, are compared. At constant temperature, control is effected in both species primarily by pulmonary ventilation, and appears to be similar in basic organization to the mammalian system. The skin CO2 exchange of the frog is largely passive and apparently under little adaptive control. CO2 exchange at different temperature is analyzed by means of the conductance equations: convective conductance [MCO2 = (VA/RT).pACO2] for lung exchange, and diffusive conductance (MCO2 = GCO2.transcutaneous deltaPCO2) for skin exchange. Predictions of conductance values, based on data for PaCO2 and MO2, agree well with measured values of both the turtle's ventilation and the frog's skin CO2 conductance at different temperatures. In each case the conductances increase only moderately, if at all, with temperature, a result that can be attributed to the similar Q10 values of PaCO2 and MO2. Because the conductances exhibit this blunted temperature dependence, both lung and skin breathers are provided with the respiratory effector mechanisms necessary to regulate PaCO2 and pHa at their characteristic values over the ectothermic temperature range.

Animals↗

The effect of temperature on cutaneous CO2, loss and conductance in the bullfrog.

Cutaneous and pulmonary CO2 loss were measured simultaneously in bullfrogs, Rana catesbeiana, at either 10, 20 or 30 degrees C. Arterial blood samples were taken in each experiment and analysed for [H+] and total plasma [CO2]. These values were used to calculate Pa(CO2) by means of the Henderson-Hasselbalch equation. Both [H+] and Pa(CO2) increased with temperature as previously observed. Skin CO2 loss was measured using a titration method. (At 30 degrees C it was necessary to add calcium hypochlorite (5-9 ppm) to block bacterial growth and respiration). Skin CO2 loss rose with temperature but the mean fraction of the total CO2 lost by this route decreased from about 50% at 10 degrees C to less than a third at 30 degrees C. At each temperature, over 90% of an incremental increase in total CO2 loss was excreted via the lungs while skin loss was relatively constant over a wide range of total loss values. The increase in skin CO2 loss with temperature corresponded to a proportional increase in the estimated transcutaneous P(CO2) difference. (This difference was assumed to equal Pa(CO2) minus ambient P(CO2.) Consequently, the skin CO2 conductance (skin CO2 loss/transcutaneous P(CO2) was not significantly influenced by temperature. This apparent temperature independence of skin CO2 conductance may be important for acid-base regulation of skin breathers in response to temperature change.

Acid-Base Equilibrium↗

Clinical use of transcatheter electrocoagulation.

Transcatheter electrocoagulation is an effective method of experimental vessel occlusion even in the presence of thrombocytopenia and heparinization. This technique was used to occlude 13 arteries in 3 patients. In vitro testing suggests that intra-arterial bipolar platinum electrodes may achieve the therapeutic objectives more rapidly and with less risk, but more investigative work is required.

Arteries↗

Tetralogy of Fallot associated with uncommon lesions.

A patient presented with a a unique combination of cardiovascular abnormalities: tetralogy of Fallot, absent pulmonary valve, stenosis of peripheral pulmonary arteries, and partial anomalous pulmonary venous connection to the azygos vein. The salient aspects and associated lesion of each of these abnormalities are described.

Abnormalities, Multiple↗

Acute gastrointestinal hemorrhage: the changing role of barium examinations.

The emergency evaluation of a patient with acute life-threatening gastrointestinal hemorrhage requires the coordinated efforts of medical, surgical, and radiologic personnel. In most patients with an acute upper gastrointestinal hemorrhage, endoscopy represents the primary diagnostic procedure. Arteriography may follow, depending on the identification of the lesion at endoscopy or the need for therapy through the vascular catheter. Arteriography should precede endoscopy when bleeding is massive or the clinical situation suggests that therapy by a catheter must be instituted on a more urgent basis. When personnel are available to perform endoscopy and arteriography, the barium examination of the upper gastrointestinal tract is best postponed for a few days until the patient can be stabilized completely. In the patient with massive red rectal bleeding and a negative nasogastric aspirate, the arteriogram is clearly the procedure of choice for the emergency diagnostic evaluation. Bleeding diverticular and vascular ectatic lesions can be diagnosed only by arteriography and treatment can usually begin immediately by a catheter infusion of vasopressin. Colonoscopic and barium enema examinations of the acutely bleeding patient are not reliable. In addition, the presence of barium in the colon interferes with arteriography for a number of hours. The barium examination of the colon should be performed at some time during the hospitalization to exclude other possible bleeding lesions and to provide a better overall anatomic assessment of the colon. Both the retrograde and antegrade small bowel enemas are useful in detecting obscure small bowel bleeding lesions that occasionally present as a massive lower gastrointestinal hemorrhage.

Adult↗

Fc receptors induced by herpes simplex virus. I. Biologic and biochemical properties.

Radioiodinated normal rabbit IgG was used to detect Fc receptors on the surface of HeLa S3-2 cells infected with herpes simplex virus (HSV). Unlike the Fc receptors present on most leukocytes, these virus-induced Fc receptors were found to be sensitivite to trypsin at concentrations of enzyme as low as 0.1 mg/ml. Treatment of infected cells with neuraminidase enhanced the binding of IgG. Yet the HSV-induced Fc receptor(s) is probably a glycoprotein because its synthesis was inhibited by 2-deoxy-D-glucose at concentrations inhibiting glycoproteins but not total proteins. Binding of radioiodinated IgG to Fc receptors on infected HeLa S3-2 cells was unaffected by F(ab')2 fragments prepared from antisera against uninfected HeLa S3-2 cells or against human beta2-microglobulin. By contrast, anti-HSV F(ab')2 or Fab' fragments decreased binding of radioiodinated IgG to HSV-infected cells by 85%, and binding of radioiodinated Fc was also inhibited by anti-HSV Fab'.

Animals↗

Renal cyst puncture and abscess formation.

Percutaneous needle puncture and aspiration of suspected cystic renal masses may provide accurate diagnosis in selected cases. However, renal cyst puncture is not a totally innocuous procedure and certain complications may be encountered. Report is made of 2 cases of renal cyst puncture followed by abscess formation, necessitating surgical intervention. An improved technique involving surgical preparation of the operative area and utilization of double-needle method of cyst puncture is advocated.

Abscess↗