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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

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↗
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↗
PubMed1979

Reversal of ischemic damage with secondary blood cardioplegia.

After severe ischemic injury, it is usually necessary to prolong bypass to enhance recovery. This study tests the hypothesis that the best reversal of ischemic damage is achieved by briefly rearresting the postischemic heart with a continuous infusion of an oxygenated cardioplegic solution (secondary blood cardioplegia) during the period when bypass must be prolonged. Twenty dogs underwent 45 minutes of normothermic ischemic arrest. Fifteen minutes after unclamping, no heart could support the systemic circulation. In all dogs, oxygen demands were lowered by extending bypass for 30 minutes. In 10 of these dogs, demands were further lowered by rearresting the heart for 5 minutes with a continuous infusion of a 37 degrees C blood cardioplegic solution (K+28 mEq/L; pH 7.6; Ca++ 1 mEq/L) at a pressure of 50 mm Hg. Hearts treated with secondary blood cardioplegia showed greater recovery in the rate of contraction (-dP/dt 75% versus 62%, p less than 0.05) and relaxation (-dP/dt 76% versus 58%, p less than 0.05), better recovery of compliance (85% versus 51%, p less than 0.05), a higher stroke work index (0.72 versus 0.50 gm-m/Kg, p less than 0.05), and more ability to augment oxygen uptake (85% versus 45%, p less than 0.05) to meet the demands of the working heart than hearts treated by prolonging bypass alone. We conclude that rearresting the heart with a brief, continuous infusion of a blood cardioplegic solution results in more complete reversal of ischemic damage than possible by prolongation of a bypass alone. We believe that the increased recovery with secondary cardioplegia results from diversion of delivered oxygen toward reparative processes rather than its being expended needlessly on electromechanical work during the time when bypass must be prolonged.

Animals↗
PubMed1978

Surgical correction of complete atrioventricular canal.

Operative mortality associated with complete atrioventricular canals has decreased from 75 per cent to as low as 10 per cent. The present report reviews the UCLA Hospital experience with the six children who underwent repair of this defect in the past two years. Emphasis is placed on preoperative assessment, operative technics, and postoperative management.

Child↗
PubMed1977

New developments in cardiothoracic surgery.

New and innovative developments in cardiothoracic surgery include the pulmonary effects of certain inotropic drugs, the role of patent ductus closure in neonatal respiratory distress syndrome, the use of immunostimulating agents as adjuvants in the treatment of cancer of the lung, ingenious operative procedures to correct transposition of the great vessels and aortic stenosis, and improved methods to protect and assist the heart during cardiac operations.

Assisted Circulation↗
PubMed1976

Phasic coronary flow: intraoperative evaluation of flow distribution, myocardial function, and reactive hyperemic response.

Using visual inspection of phasic flow patterns and understanding their physical determinants, intraoperative decisions regarding flow distribution, function of revascularized myocardium, and collateral communications can be made. Mean flow measurements cannot provide this information. Systolic compressive forces across most of the normally contracting left ventricle limit systolic myocardial perfusion. Consequently, normal flow through the left anterior descending, left circumflex, and dominant right coronary artery (supplying the inferior left ventricle) is predominantly diastolic (greater than 60%) and remains so during reactive hyperemia. Representative examples from 100 consecutive revascularizations are presented showing that when more than 40% of flow is systolic in the right coronary artery, high mean flows (greater than 100 ml/min) may go predominantly to the right rather than the left ventricle; in the case of the left coronary artery, high mean flow may supply myocardium undergoing infarction or replaced by scar rather than normally contracting muscle. When more than 60% of flow is diastolic without reactive hyperemia, borderline mean flow (40 to 60 ml/min) may indicate lack of distal ischemia rather than fixed distal resistance.

Arterial Occlusive Diseases↗