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Biomedical subjects

D S Mulder

Publications and source records attributed to D S Mulder.

At least 73 records · Page 4Linked to original sources
PubMed1982

Bioactive antibiotic levels in the human aorta.

A new bioassay was used to determine the level of active antibiotic within the aortic wall in 24 patients undergoing elective aortic surgery involving prosthetic grafts. The patients were divided into three groups and received either cefazolin, clindamycin, or cefoxitin intravenously at the induction of general anesthesia. Cefazolin and cefoxitin attained satisfactory tissue levels. Clindamycin did not reach therapeutic levels in the aortic wall. Blood levels did not correlate well with tissue levels.

Adipose Tissue↗
PubMed1981

A coded study of antitumor immunity to human lung cancer assayed by tube leukocyte adherence inhibition.

The present study was undertaken to evaluate the specificity of antitumor immunity to human lung cancer, measured by an in vitro assay--tube leukocyte adherence inhibition (LAI). We standardized and monitored the putative tumor antigen activity of the extracts by testing leukocytes from controls and patients with lung cancer in the Montreal General Hospital. A specific antitumor response to a lung cancer antigen was detected with coded leukocytes from 56% (20 out of 36) of patients with epidermoid lung cancer. By contrast, 4% (2 out of 53) of patients with inflammatory lung disease and none of 46 other patients with cancer metastatic to the lung or with other diagnoses had an LAI-positive result. The LAI response was inversely related to the extent of cancer: 80% (8 of 10) with Stage I, 66% (2 of 3) with Stage II, 54% (6 of 11) with localized Stage III, and 33% (4 of 12) with widespread Stage III were LAI positive. Leukocytes from patients with epidermoid, adenocarcinoma, or small cell lung cancer reacted to a common tumor antigen shared by extracts of epidermoid and small cell lung cancer. This study with coded samples from a remote hospital confirms the results of other investigators that the LAI measures an antitumor immune response to human organ-specific neoantigens.

Adenocarcinoma↗
PubMed1981

Mechanical and cellular bacterial clearance in lung atelectasis.

A pig model with aerosolized pneumococcal bacteria was used to establish that bacterial clearance in a collapsed lung in the perioperative period was decreased compared with the opposite, aerated lung. Cannulation of the right lymphatic duct revealed a significant increase in both lymph flow and ratio of lymph to plasma protein, indicating the development of a high-permeability edema in the collapsed, infected lung. Only 22% of the efferent lymph and blood was positive for the infecting organism. Examination of the T cells obtained by bronchopulmonary lavage showed an initial fall in the numbers of alveolar macrophages at 6 hours after collapse and infection, relative to the opposite, control lung. However, at 24 hours, the collapsed lung had replenished its alveolar macrophage population to such a degree that it was greater than the control. Electron microscopy revealed that the macrophages in the collapsed lung were more activated with increased lysosomal and pseudopodial activity. The in vitro chemotactic function of the macrophages appeared depressed, but phagocytosis and intracellular bactericidal activity were increased in the atelectatic lung. We conclude that there is a decreased bacterial clearance capacity in atelectasis. This finding indicates that impaired mucociliary clearance plays the dominant role in susceptibility to infection.

Animals↗
PubMed1981

Iatrogenic false aneurysms.

Of 270 patients operated upon for aneurysm, 25 patients underwent repair for 28 iatrogenic false aneurysms. Of these, 67.9% were complications of vascular reconstructive surgery and 64.3% occurred at the groin. Iatrogenic false aneurysm was associated with various prosthetic and suture materials and in many the attenuation of host arterial wall appeared to play an important role. Newer invasive procedures, such as arterial infusion of chemotherapeutic agents, also lead to formation of iatrogenic false aneurysm. Infections, present in 50% of the author's series, and intra-abdominal iatrogenic false aneurysm, with abdominal viscera forming part of the aneurysmal wall, posed a technical challenge. Iatrogenic false aneurysm is a potentially grave complication since the mortality and limb loss were each 8% in this series.

Aneurysm↗
PubMed1980

Myocardial cations and trace metals in cardioplegia: a clinical study.

Cations and trace metals play important roles in the pathophysiology of myocardium, and understanding their changes during cardioplegia may be important in further refining the technique of myocardial protection. Serial myocardial, blood and urine samples were taken from 12 patients undergoing cardiac operation under cold cardioplegia. The concentrations of calcium, magnesium, zinc and copper were measured with an atomic absorption spectrometer. Myocardial magnesium levels were found to be significantly (P less than 0.05) depleted when the "cardioplegic" solution contained 0.69 mmol/l of magnesium, but this could be prevented by increasing the magnesium concentration of the infusate to 2.2 mmol/l. With calcium-free infusate, the myocardial calcium concentration decreased, but zinc and copper values did not change significantly. There were decreased serum concentrations of these cations and trace metals during tbe hemodilution cardiopulmonary bypass but their 24-hour excretions in urine were within normal range. Although the clinical importance of such changes remains to be elucidated, the information may be valuable in designing future cardioplegic solutions with optimal compositions.

Calcium↗
PubMed1980

Symposium on trauma. 2. Chest trauma: current concepts.

Blunt chest trauma continues to be an important cause of death following motor vehicle accidents in Canada. Current methods of diagnosis are presented emphasizing a physiologic approach. The most important physiologic consequence of trauma associated with chest wall instability or ruptured diaphragm is pulmonary contusion. Current therapy therefore stresses the treatment of pulmonary contusion (Trinkle's regimen) rather than the associated chest wall instability. A widened mediastinum or a fractured first rib on the chest film, or upper limb hypertension should suggest possible rupture of the aorta, which can be confirmed by aortography. Early surgical repair is recommended. Current techniques for repair are detalied. Cardiac tamponade and exsanguinating hemorrhage are the common causes of death following cardiac trauma. Methods for recognizing and treating cardiac tamponade are outlined. The indications for early thoracotomy following cardiac trauma are listed; thoracotomy should be done in a fully equipped operating room rather than the emergency room. Successful management of major chest injuries requires an aggressive physiologic approach to diagnosis and emphasis on maintaining effective ventilation and adequate cardiac output.

Aortic Rupture↗
PubMed1979

Intraoperative blood-flow responses in coronary artery bypass grafts.

Intraoperative graft flow responses in 15 patients who underwent coronary artery bypass grafting (CABG) were studied systematically. The mean blood flow for 13 left anterior descending (LAD) coronary artery grafts was 64 +/- 20 ml/min and for 12 right coronary artery (RCA) grafts was 53 +/- 13 ml/min. Of these, systolic flow was dominant in one LAD and three RCA grafts, suggesting the perfusion of the right ventricle or the noncontractile left ventricle segment, or both. Five LAD and two RCA grafts had a negligible reactive hyperemic response, and the underlying cause for this can be futher examined by observing their phasic flow patterns. Temporary occlusion of the coronary artery proximal to the site of anastomosis produced increased flow in 8 grafts, indicating the presence of competitive flow; decreased flow was observed in 15 grafts, indicating the presence of proximal retrograde flow which may play a role in the proximal occlusion of the bypassed artery later. Thus intraoperative flow studies supplement the preoperative angiographic findings in elucidating the pathophysiology involved and are useful in evaluating CABG operations.

Adult↗
PubMed1978

'Downhill' esophageal varices. A rare cause of upper gastrointestinal bleeding.

The submucosal venous network of the esophagus is part of the collateral system that develops following superior vena caval obstruction from any cause. The direction of flow in these thin-walled, valveless veins is "downhill," towards the azygous vein or to the inferior vena cava. Bleeding from upper esophageal varices is extremely rare. This case report describes a patient with massive bleeding from upper esophageal varices secondary to superior vena caval obstruction by a malignant thyroid tumor. Total thyroidectomy relieved the obstruction, with cessation of hemorrhage and subsequent disappearance of the varices.

Aged↗
PubMed1978

Management of extremity with combined neurovascular and musculoskeletal trauma.

Twenty-five civilians with combined neurovascular and musculo-skeletal trauma to 27 extremities were studied retrospectively. The mechanism of injury was crushing in 16, avulstion in six, and penetrating in three. Autogenous saphenous vein was used to restore arterial circulation in the majority. Nine patients had concurrent repair of venous injuries. Fractures were immobilized by a variety of techniques, the Hoffman external skeletal fixation being preferred. Immediate fasciotomy was performed in five patients and delayed fasciotomy in four. All patients had soft-tissue debridement and initial wound closure with split-skin grafts as biologic dressings. Three immediate amputations were the result of irreversible neurovascular and soft-tissue trauma. Sepsis played a role in three late amputations; delayed primary treatment,, irreversible neurologic injuries and extensive soft-tissue damage contributed. A carefully individualized multidisciplinary approach resulted in salvage of 20 of 27 severely injured extremities.

Adolescent↗
PubMed1978

Endobronchial lymphoscintigraphy (EBLS). New diagnostic modality.

A safe, simple method of visualizing deep intrathoracic lymph nodes and determining regional tracheobronchial lymphatic drainage with colloidal radionuclides has been developed. The tracer is injected submucosally via a bronchoscope and lymph node scanning is performed at least 2 hours later. The technique was developed and tested in seven canine experiments. Endobronchial lymphoscintigraphy (EBLS) has been performed in 43 patients undergoing routine bronchoscopic examination. 99mTc phytate, 198Au colloid, and 99mTc antimony sulfide have been used; the last appears to have been the most satisfactory. The primary lymphatic drainage from selected sites of the tracheobronchial tree could be determined. Up to five lymph nodes have been visualized, with an average of 2.1 lymph nodes seen in those patients with lymph node visualization. Four patterns of lymphatic drainage were seen; ipsilateral ascending, contralateral ascending, descending, and no spread of injected colloid. In some cases cervical and celiac lymph nodes were seen. In combination with conventional diagnostic methods, EBLS in many cases clarified the extent and nature of underlying disease.

Aged↗
PubMed1977

Spontaneous aortocaval fistula secondary to ruptured abdominal aortic aneurysm.

Two patients with the rare condition of spontaneous aortocaval fistula secondary to ruptured abdominal aortic aneurysm were treated successfully by surgical closure of the fistula. In view of the existing controversies on certain aspects of the pathophysiology involved, canine experiments were performed to elucidate the pathogenesis of regional venous hypertension and hematuria observed in these patients. The experiments demonstrated that regional venous hypertension is a purely rheologic phenomenon and that hematuria originates from a congested lower urinary tract.

Animals↗
PubMed1976

Pericardiectomy for uremic tamponade.

Pericardial tamponade developed in 29 patients with uremia. The clinical presentation varied, some patients having no symptoms whereas others sustained circulatory collapse. Pericardial friction rub, elevated central venous pressure and a paradoxical pulse were the most common physical findings. Serial chest radiography and echocardiography were most useful procedures in confirming this diagnosis. Two patients were treated conservatively and died despite repeated pericardiocentesis. The remaining 27 patients underwent partial pericardiectomy. One patient died of cardiorespiratory failure and a second from brain damage related to cardiac arrest before pericardiectomy. The other 25 patients reported immediate relief of symptoms and no recurrence of pericarditis. Pericardiectomy is the treatment of choice in uremic pericardial tamponade.

Adolescent↗
PubMed1975

The use of the fiberoptic bronchoscope to facilitate endotracheal intubation following head and neck trauma.

The fiberoptic bronchoscope is an invaluable aid in the difficult endotracheal intubation. Its successful use with three patient groups is described: those with soft-tissue contractures of the mouth or neck; those with severe fractures of facial bones and/or mandible; those with unstable fractures or fracture-dislocations of the cervical spine. Fiberoptic bronchoscopy is felt to be the technique of choice when intubation is difficult, especially when there are contractures or deformities of the larynx, manidible, or cervical spine.

Adult↗