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Biomedical subjects

D G Mulder

Publications and source records attributed to D G Mulder.

At least 19 recordsLinked to original sources
PubMed1992

Autoimmune disease and the nervous system. Biochemical, molecular, and clinical update.

Autoimmunity in the central and peripheral nervous system can manifest as the result of cellular or humoral immune responses to autoantigens. There is evidence that multiple sclerosis is a cell-mediated autoimmune disease of the central nervous system in which both myelin and the cell that produces the myelin are destroyed. Diseases such as acute inflammatory demyelinating polyneuropathy (also called Guillain-Barré syndrome) and myasthenia gravis are considered antibody-mediated diseases of the peripheral nervous system and neuromuscular junctions, respectively. We review these diseases and explore mechanisms of immune-mediated destruction of these nervous system components. We specifically focus on one effective therapy aimed at countering the immune attack, that of thymectomy in patients with myasthenia gravis.

Autoimmune Diseases↗
PubMed1991

Repair of large paraesophageal hernia with complete intrathoracic stomach.

Paraesophageal hiatal hernia accounts for only five per cent of all diaphragmatic defects but is a potentially dangerous lesion. Herniation of the entire stomach, at times accompanied by the omentum, transverse colon, and small bowel, may occur in some patients, and incarceration and strangulation may be the result. Three patients underwent repair of large paraesophageal hernias, in one instance as an emergency. Symptoms of pain, bloating, and occasional regurgitation had been present for 17, 30, and 40 years. The operations included repair of the hiatal defect, anterior gastropexy, and Nissen fundoplication in two patients. In the third patient, a pyloromyotomy was performed as well. A subsequent thoracotomy was necessary in one patient to excise a persistent large hernia sac, which was densely adherent to the lung and mediastinal structures. All patients were asymptomatic after periods of 9 months, 1 year, and 7 years. The unique anatomic and clinical features of large paraesophageal hernias containing intrathoracic abdominal viscera, as well as the technique of operative repair, are presented.

Adult↗
PubMed1989

Management of huge epiphrenic esophageal diverticula.

Epiphrenic diverticula occur in association with motor disorders of the distal esophagus, including achalasia and diffuse esophageal spasm. Four patients with huge symptomatic epiphrenic diverticula are presented to emphasize the need for complete radiographic and manometric studies of the esophagus to document this motor dysfunction prior to performing combined diverticulectomy and esophagomyotomy. Each patient had achalasia with symptoms extending from 4 to 25 years. Diverticulectomy and esophagomyotomy were performed in every patient. One patient had previously undergone diverticulectomy alone, with prompt recurrence of the lesion. During a follow-up period extending from 2 to 10 years, three patients were alive and well. One patient developed recurrent dysphagia due to reflux esophagitis and stricture requiring dilatation. It is essential that esophagomyotomy be part of the initial operative procedure. In selected patients, an antireflux procedure may also be indicated.

Aged↗
PubMed1989

Long-term survival after triple-valve replacement.

A 29-year-old man with rheumatic stenosis and insufficiency of the aortic, mitral, and tricuspid valves underwent urgent triple-valve replacement on January 12, 1966, because of uncontrollable congestive heart failure. Twenty-two years and 8 months later (September 13, 1988) reoperation was necessary to replace the Kay-Shiley tricuspid prosthesis because of progressive stenosis of the valve due to pannus formation. The aortic and mitral prostheses continue to function normally. The patient has again returned to full activity.

Adult↗
PubMed1989

Thymectomy for myasthenia gravis: recent observations and comparisons with past experience.

To our previous report on the results of thymectomy for myasthenia gravis in 249 patients operated on between 1954 and 1981, we add a current review of 84 patients treated between 1982 and 1987. All patients underwent a median sternotomy, although this was performed after a bilateral submammary skin incision in most of the 57 female patients. There were no operative deaths, but one late death occurred at 5 months. During a mean followup of 3.6 years, 67 patients (80%) benefited from operation with remission achieved in 30 (36%) and improvement noted in 37 (44%). Acetylcholine receptor site antibody was present in 43 patients, of whom 19 (44%) achieved remission in contrast to 9 (27%) of the 33 patients without antibody. Hyperplasia of the excised thymus in 38 patients was associated with remission in 20 (53%) in contrast to remission in 7 (20%) of the 35 patients whose glands were "normal" or atrophic. The best prognosis was found in the 23 patients who had both receptor site antibody and thymic hyperplasia, as remission occurred in 15 of them (65%) in contrast to only 6 (27%) of the 22 patients who had neither factor. Remission rates (remissions per 1,000 patient-months of follow-up) for the present series (84 patients), the previous group (249 patients), and the overall group (333 patients) are 9.95, 6.13, and 6.62, respectively.

Adult↗
PubMed1987

Magnetic resonance imaging of the thoracic aorta.

Forty-one patients with a variety of suspected aortic lesions underwent magnetic resonance imaging (MRI) of the thoracic aorta. Patients were separated into 2 groups: Group A included 19 patients who underwent MRI after arteriography for comparison purposes and were evaluated retrospectively. Surgical confirmation was obtained in 9 of these patients. Group B included 22 patients who were studied prospectively because of abnormal chest x-ray, ultrasound or computerized tomographic findings and did not undergo arteriography before MRI. Two patients from this group had surgery. In group A, MRI correlated with the surgical or angiographic findings in 18 of 19 patients (95%). In group B, MRI was considered of diagnostic quality in all patients and no other invasive or noninvasive imaging modalities were needed for diagnosis and treatment. Thus, MRI will replace arteriography in a large proportion of patients with suspected thoracic aortic lesions.

Aorta, Thoracic↗
PubMed1987

Penetrating injuries by large objects. Presentation of three cases and review of literature.

Penetrating injuries with large objects are uncommon but dramatic. Immobilization of the patient and stabilization of the penetrating object during transport and administration of basic emergency support are essential to avoid increasing the damage already sustained. The object as well as the organs and vessels in its path should be exposed and controlled in the operating room prior to removal of the object. Thorough inspection, evaluation, and repair of injured structures can then be carried out. Aggressive prophylactic medication to prevent infection may further contribute to the improved survival of these patients.

Adolescent↗
PubMed1987

Congenital esophagobronchial fistula in an adult.

Congenital esophagobronchial fistula occurring in infancy and childhood is a well-recognized entity necessitating urgent surgical treatment. Persistence of such a communication into adulthood is rare and would seem possible only if the tract were small so that aspiration into the lung could be tolerated. The case of a 38-year-old woman is presented in this report who was cured of lifelong symptoms of aspiration by surgical division of a presumed congenital esophagobronchial fistula.

Adult↗
PubMed1986

Thromboembolic obstruction of the pulmonary artery treated by endarterectomy.

Endarterectomy of a totally occluded right pulmonary artery by median sternotomy with cardiopulmonary bypass and intermittent circulatory arrest is described. The nature of the thrombus encountered and brisk backbleeding from the endarterectomized vessels predicted the functional improvement seen in the patient postoperatively. Reperfusion edema, which often complicates pulmonary artery thromboendarterectomy, was not observed. Preoperative assessment, postoperative management, and technical aspects of the operative procedure used in treating patients with thromboembolic obstruction of the pulmonary arteries are discussed.

Adult↗
PubMed1986

Intraoperative measurement of pericardial constraint: role in ventricular diastolic mechanics.

The pressure of pericardial constraint was measured in 20 patients undergoing elective cardiac surgery (10 in Group I with normal cardiac size; 10 in Group II with cardiomegaly) using a catheter with a collapsible latex end balloon. Right atrial pressure and other hemodynamic variables including right ventricular stroke work index were also measured before and after the pericardium was widely opened. The pericardium was grossly normal in all patients and only small physiologic effusions were present. In Group I mean pericardial pressure was 8 +/- 2 mm Hg as was mean right atrial pressure. In Group II mean pericardial pressure was 6 +/- 2 mm Hg versus mean right atrial pressure of 10 +/- 5 mm Hg (p less than 0.05). Excluding 2 of the 20 patients with outlying data, pericardial pressure showed linear correlation with right atrial pressure (r = 0.689). In Group I right ventricular stroke work index rose from 5.0 +/- 2.0 to 6.4 +/- 2.1 g-m/m2 (p less than 0.01) after pericardiotomy with no significant increase in mean right atrial pressure; similar findings in Group II were consistent with removal of external constraint. Thus, even in the absence of an abnormal effusion the normal pericardium exerts a significant pressure on the heart, which is often similar in magnitude to right atrial pressure. In certain notable exceptions, however, right atrial pressure far exceeds pericardial pressure. Such pericardial constraint has important implications for ventricular diastolic mechanics.

Biomechanical Phenomena↗
PubMed1986

Mitral valve replacement complicated by unsuspected pheochromocytoma.

This report describes the case of a 65-year-old woman who underwent elective mitral valve replacement complicated by a malignantly vasoactive pheochromocytoma. The early recognition of this condition and the importance of immediate and aggressive pharmacologic intervention are discussed.

Adrenal Gland Neoplasms↗
PubMed1985

Myasthenia gravis--current concepts.

An edited summary of an Interdepartmental Conference arranged by the Department of Medicine of the UCLA School of Medicine, Los Angeles. The Director of Conferences is William M. Pardridge, MD, Associate Professor of Medicine. Current findings indicate that autoimmune myasthenia gravis is an acquired immune complex disorder of neuromuscular transmission in voluntary striated muscle. There is a break in immunologic tolerance leading to blocking and degradation of acetylcholine receptors, together with widening of the synaptic cleft associated with partial destruction, simplification and shortening of the postjunctional membrane. Thymic hyperplasia and thymoma may be present. A decremental response to nerve-muscle stimulation, blocking and jitter on single-fiber electromyography and circulating antibodies to acetylcholine receptor are detectable in most patients with generalized weakness. Although the cause of this abnormal immunologic mechanism remains to be discovered, anticholinesterases, corticosteroids, immunosuppressants, plasmapheresis or thymectomy (individually or in combination) provide control and better prognosis in most patients.

Acetylcholine↗
PubMed1979

Surgical management of extensive tracheal lesions.

Resection and end-to-end anastomosis has been effective in correcting localized tracheal obstruction. This procedure can be utilized in the definitive management of extensive tracheal lesions requiring the resection of at least eight tracheal rings. Important clinical considerations are the precise preoperative assessment of the lesion, careful planning of anesthetic management, choice of the appropriate incision, avoidance of circumferential dissection, and the construction of an anastomosis free of disruptive tension.

Adult↗
PubMed1979

The use of computed tomography to evaluate suspected mediastinal tumors.

Thirty patients with suspected mediastinal tumors were evaluated by computed tomography (CT) at UCLA Medical Center. Twenty patients with myasthenia gravis were examined for possible thymomas, benign and malignant; and 10 patients were studied for other mediastinal masses (including teratoma, seminoma, mediastinal lipomatosis, carcinoma, lymphoma, and paravertebral abscess). The CT scan was found useful in several respects: (1) yielding information not available by conventional radiographic techniques; (2) defining the anatomical location and extent of mediastinal tumors; (3) detecting pulmonary metastasis and involvement of mediastinal nodes in cases of malignancy; and (4) establishing the diagnosis of benign mediastinal fatty masses. On the basis of our early experience, we believe CT is a valuable adjunct in the preoperative assessment of patients with suspected mediastinal tumors.

Humans↗
PubMed1979

Diagnosis and management of postoperative pulmonary hypertensive crisis.

In this paper we discuss two infants and one child who experienced a previously unreported complication after complete correction of a large, unrestrictive ventricular septal defect. Two patients had documented pulmonary hypertensive crises and severe right-heart failure secondary to hypoxia and pulmonary vasoconstriction. These crises were associated with significantly increased right ventricular (RV) peak systolic and end-diastolic pressures and right-to-left shunting via a foramen ovale which, in turn, exaggerated the hypoxis. The crises were treated successfully with tolazoline in the second and third patients. RV pressure returned to normal values and have remained normal up to 12 months postoperatively in the second patient. Although the RV pressures decreased with tolazoline in the third patient, they never reached normal values. Postoperative monitoring of pulmonary artery and RV pressures in infants with large ventricular septal defects is essential when unexplained complications are encountered. Tolazoline proved to be very effective in the treatment of two patients with pulmonary vasoconstriction secondary to hypoxia.

Heart Septal Defects, Ventricular↗