Search PubMed⌕ Search

Biomedical subjects

R W Anderson

Publications and source records attributed to R W Anderson.

At least 145 records · Page 8Linked to original sources
PubMed1983

Lymphocyte abnormalities in preleukemia--I. Decreased NK activity, anomalous immunoregulatory cell subsets and deficient EBV receptors.

The development of acute non-lymphocytic leukemia is preceded by a set of symptoms described as the preleukemia syndrome. Six patients who fulfilled the criteria for this preleukemia syndrome have been evaluated for abnormalities in the lymphocyte population. The NK cell activity was reduced, the immunoregulatory cell populations were numerically abnormal, and the B cell subpopulation was deficient in EBV receptors. Thus, in addition to the abnormalities in the myeloid populations, there are serious defects in the lymphoid systems of preleukemic patients.

Adult↗
PubMed1983

Prevention of recurrent sudden cardiac arrest: role of provocative electropharmacologic testing.

This study evaluates the usefulness of serial provocative electropharmacologic testing for predicting the efficacy of prophylactic antiarrhythmic treatment regimens in patients resuscitated from sudden cardiac arrest in the absence of acute myocardial infarction. Testing was carried out in 34 consecutive patients (28 men and 6 women) who required cardiopulmonary resuscitation and direct current countershock for treatment of primary ventricular fibrillation (28 patients), ventricular tachycardia (5 patients) or excessively rapid heart rate during atrial fibrillation with preexcitation (1 patient). In 8 (24%) of the 34 patients, drug testing either was not feasible because of absence of inducible arrhythmia or was incomplete because of patient withdrawal from study; and 3 of these 8 patients had recurrent sudden cardiac arrest within 10 to 19 months. In an additional five patients, treatment regimens failed to prevent initiation of sustained ventricular tachyarrhythmias in the catheterization laboratory, and two of these five patients had cardiac arrest recurrences within 2 weeks to 25 months of follow-up. In the remaining 21 (62%) of the 34 patients, including 3 patients with preexcitation syndrome, a drug regimen or surgical treatment, or both, was found that prevented inducible life-threatening tachyarrhythmias in the laboratory. Subsequently, only 1 (5%) of these 21 patients died suddenly within a 7 to 38 month (mean +/- standard deviation, 18 +/- 8.3) follow-up period. Thus, provocative electropharmacologic testing appears to be useful in predicting response to therapy in survivors of sudden cardiac arrest.

Adolescent↗
PubMed1983

Alterations in left ventricular three-dimensional dynamic geometry and systolic function during acute right ventricular hypertension in the conscious dog.

Fifteen chronically instrumented, conscious dogs were studied to determine whether, in the intact circulation, mechanical interactions dictated by the anatomic contiguity of the two ventricles significantly alter left ventricular (LV) dynamic geometry and systolic function during acute right ventricular (RV) hypertension. The three-dimensional geometry of the left ventricle was monitored with three pairs of ultrasonic dimension transducers; ventricular pressures were measured with micromanometers. Data collected during pulmonary artery constriction (RV pressure 68 +/- 8/7 +/- 4 mm Hg) were compared with control data collected at matched heart rates (RV pressure 32 +/- 8/4 +/- 4 mm Hg). During pulmonary artery constriction, mean calculated LV end-diastolic volumes decreased from 69.2 +/- 20.0 to 56.2 +/- 21.3 cm3 (p less than or equal to 0.05). Mean systolic stroke volume decreased from 20.6 +/- 5.5 to 14.0 +/- 6.3 cm3 (p less than or equal to 0.05). These changes were entirely accounted for by alterations in the behavior of the LV septal-free wall minor axis and rearrangements in LV equatorial geometry. When the pulmonary artery was constricted, elongation of the septal-free wall axis occurred during isovolumic systole and was accompanied by a reciprocal decrease in anterior-posterior dimension. Most of the decrease in septal-free wall dimension occurred during relaxation and early diastole rather than during ejection. Mean septal-free wall end-diastolic dimension decreased from 5.45 +/- 0.69 to 4.90 +/- 0.75 cm (p less than or equal to 0.05). The mean systolic decrease in septal-free wall dimension fell from 0.36 +/- 0.18 to 0.14 +/- 0.22 cm (p less than or equal to 0.05). The end-diastolic dimensions and systolic shortening of the LV anterior-posterior minor axis and base-apex major axis were not significantly altered by pulmonary artery constriction. These findings suggest that during acute RV hypertension, impairment of LV systolic function and rearrangements in LV dynamic geometry are primarily the result of the anatomic contiguity of the two ventricles.

Animals↗
PubMed1983

A combined atrial/ventricular lead for permanent dual-chamber cardiac pacing applications.

A new urethane insulated dual unipolar atrial/ventricular transvenous lead has been developed to facilitate implantation of permanent dual-chamber cardiac pacing systems in man. The atrial portion of the lead has tines and is designed to retain a permanent J configuration, while the coaxially situated ventricular lead is freely and independently adjustable and incorporates a ring tip electrode with four urethane tines. Our initial experience with the dual lead in one patient is reported herein and suggests that combined atrial/ventricular pacing leads are feasible and may obviate need for implantation of two separate pacing electrodes in patients being considered for permanent dual-chamber pacing.

Electrodes, Implanted↗
PubMed1983

Root surface measurements of mandibular molars using stereophotogrammetry.

Ten mandibular first molars were hemisected and the root surface of each root was measured using stereophotogrammetry and computer analysis. In each tooth the mesial root was determined to have a greater surface area than the distal root. This difference was statistically significant. The fact that the mesial root has the larger surface area must be a consideration when hemisection is planned.

Humans↗
PubMed1983

Studies of T-lymphocytes in preleukemic disorders and acute nonlymphocytic leukemia: in vitro radiosensitivity, mitogenic responsiveness, colony formation, and enumeration of lymphocytic subpopulations.

Tritiated thymidine incorporation in a whole blood lymphocyte stimulation test (LST) and lymphocyte colony formation (CFU-L) from whole blood were measured following in vitro x-irradiation. Lymphocytes from patients with myelodysplastic disorders, acute nonlymphocytic leukemia, and patients at increased risk for leukemia because of their primary disease and/or cytotoxic therapy were found to be significantly more sensitive to in vitro x-irradiation than lymphocytes from clinically normal individuals. Cloning efficiencies and mitogenic responsiveness of patient lymphocytes were significantly depressed as compared to normal values. Using monoclonal antibodies to specific surface markers, quantitative abnormalities in lymphocytic subpopulations from myelodysplastic patients also were observed. These findings are suggestive of a defect at the T-cell level that may directly or indirectly affect hematopoiesis.

Acute Disease↗
PubMed1983

Deficiency in Epstein-Barr virus receptors on B-lymphocytes of preleukemia patients.

Lymphocytes from eight preleukemia patients were exposed to Epstein-Barr virus (EBV) in vitro in an attempt to establish lymphoblastoid cell lines. No signs of viral infection were detected, and no cell lines were obtained. Studies using fluorescein-labeled EBV and flow cytometry revealed an unusual and consistent deficiency in EBV receptors in all patients examined. In control studies, about 15% of the unseparated lymphocytes from healthy donors bound fluorescein-labeled EBV. In spite of the lack of EBV receptors, B-lymphocytes amounted to 10 to 20% of the preleukemia lymphocyte populations, a proportion similar to that in healthy donors. When lymphocytes from preleukemic patients were first implanted with functional EBV receptors and then exposed to EBV, synthesis of EBV-determined nuclear, early, and viral capsid antigens was induced. Subsequently, several cell lines originating from preleukemic patients' lymphocytes were established. These lines are of a B-lymphocyte origin and carry EBV genome. They will provide experimental material for the molecular analysis of lymphocytic defects in preleukemia and their possible role in the transition to acute leukemia.

B-Lymphocytes↗
PubMed1983

Characteristics of ventricular function in severe hemorrhagic shock.

Although left ventricular (LV) function appears altered by severe hemorrhagic shock (HS), the mechanisms of this dysfunction have been difficult to characterize. Depression in the LV function curve could be caused by altered diastolic or systolic function. It has been difficult to assess the systolic function, but the use of the rate and load independent index of contractility, Emax (the slope of the end-systolic pressure-dimension relationship), offers a new approach to the quantification of systolic mechanical performance. Emax and the LV diastolic pressure-strain relationship were measured in 15 chronically instrumented dogs by sonomicrometric and micromanometric techniques. Gradual LV unloading was obtained from transient vena caval occlusion. After control study, each dog underwent 2 hours of HS (mean aortic pressure 40 mm Hg), followed by reinfusion of all shed blood. Upon reinfusion, Emax was not decreased; however, all dogs had a significant decrease in LV compliance. During the next 4 days, the LV compliance of the eight survivors progressively returned toward control, while Emax remained stable. All seven nonsurvivors demonstrated progressive loss of LV compliance, and Emax was significant decreased prior to death. Cardiac contractility appeared improved immediately after shock, but a consistent decrease in compliance was observed. Reversal of abnormal diastolic function was demonstrated in all survivors and progressive depression in all nonsurvivors. Depression in systolic function was observed only in nonsurvivors immediately prior to death.

Animals↗
PubMed1982

Onset of atrial fibrillation during antidromic tachycardia: association with sudden cardiac arrest and ventricular fibrillation in a patient with Wolff-Parkinson-White syndrome.

Electrophysiologic evaluation in an 18 year old youth with the Wolff-Parkinson-White syndrome who had a sudden cardiac arrest while playing racquetball revealed two types of paroxysmal reciprocating tachycardia: (1) A normal QRS tachycardia with a short ventriculoatrial (V-A) interval fulfilled the criteria for reentry within the atrioventricular (A-V) node; and (2) a wide QRS tachycardia with a QRS configuration of maximal preexcitation was demonstrated to be the result of an antidromic mechanism. During laboratory study, the wide QRS tachycardia spontaneously degenerated into atrial fibrillation. In the basal state, the shortest R-R interval between preexcited QRS complexes was 270 ms, but after infusion of isoproterenol (1.6 microgram/min intravenously), the shortest R-R interval became 180 ms. Consequently, this electrophysiologic study suggested that evolution of antidromic reciprocating tachycardia into atrial fibrillation with a rapid ventricular response during exercise-induced catecholamine release may have been the mechanism for ventricular fibrillation in this patient.

Adolescent↗
PubMed1982

Mediastinal nonseminomatous germ cell tumors: the role of combined modality therapy.

Twelve male patients with mediastinal nonseminomatous germ cell tumors were treated with chemotherapy (with or without operation and radiation therapy) between 1963 and 1980. Eight patients, treated with only chemotherapy and radiotherapy, died with a median survival from diagnosis of 6 months (range, 3 to 12 months). The 4 survivors remain alive at 12, 15, 34, and 56 months from diagnosis; all are without evidence of disease. All surviving patients were treated with surgical resection of disease either before of after chemotherapy. A major problem in the management of mediastinal nonseminomatous germ cell tumors is the persistence of local disease, which may be overcome by vigorous cytoreductive intervention. Multicenter collaboration will be required to define the optimal combined-modality approach.

Adolescent↗
PubMed1982

Successful surgical treatment of anuria caused by renal artery occlusion.

Anuria resulting from obstruction of the renal arteries to both Kidneys or to a solitary kidney is unusual. The tolerance of the kidney to this ischemia is largely dependent upon the presence of collaterals, stimulated by pre-existing arterial disease. Our experience with six patients with anuria caused by renal artery occlusion supports the role of revascularization in the recovery of significant renal function. Four of these patients had hypertension, impaired renal function, and the existence of collateral circulation to an ischemic kidney, prior to occlusion, while two patients had normal renal function (serum creatinine = 0.5 and 0.9 mg/dl) before occlusion. The intervals of anuria for the two previously normal kidneys were six hours and five days, and 2 to 14 days in the four patients with vascular disease. Isotope scanning suggested renal artery occlusion in two patients, but arteriograms confirmed the diagnosis in all six. A thrombectomy restored blood flow through the two previously normal renal arteries. Grafts from the aorta or celiax axis were used for three patients and the splenic artery was used for the sixth patient. Urine flow began during or soon after operation in all patients. Dialysis was necessary for 30 and 45 days in the two patients with normal kidneys, but in only one of the four patients with previous disease (for ten days). Serum creatinine decreased to <2.0 mg/dl after operation, except in the man with a solitary kidney, who five years later has a creatinine of 3 mg/dl. All four patients with previous arterial disease died from cardiac failure within 1 to 30 months after operation. Therefore, anuria of acute onset should be evaluated by renal scan and arteriogram to detect those patients with proximal renal artery occlusion in preparation for revascularization.

Adolescent↗
PubMed1982

Balloon dilatation of excised aortic coarctations.

Seven children 1-6 years of age underwent aortic resection and re-anastomosis for coarctation of the thoracic aorta. The excised segments were 1-2 cm long and were dilated in vitro with a Grüntzig balloon catheter less than two hours after resection. A pressure of 4-8 atmospheres was used, and the inflated diameter of the balloon was twice the luminal diameter of the undilated coarctation. The diameter of each specimen was increased by an average of 85%, largely because of an increase in the external diameter of the coarctation. However, extremely high pressures were required for successful dilatation, producing transmedial tears in the "normal" aorta distal to the coarctation in three specimens. These results indicate that although balloon dilatation appears feasible as palliation for aortic coarctation, further studies of its safety are necessary before instituting clinical trials.

Angioplasty, Balloon↗
PubMed1982

Renal disease in cryoglobulinemia type II: response to therapy. A case report and review of the literature.

A case of cryoglobulinemia type II with membranoproliferative glomerulonephritis and vasculitis is described. Clinically and serologically the patient responded to cyclophosphamide and prednisone therapy. This correlated with improvement in the glomerular and interstitial lesions on renal biopsy specimens, although skin and renal vasculitis persisted over a 2-year period. These observations suggest important differences in the immunopathologic mechanisms involved in the vascular versus glomerular injury. Infiltration of macrophages were demonstrated in the glomerular capillary lumen while polymorphonuclear cells predominated in the vascular lesion. The presence of macrophages in the glomerular capillary lumen correlated with clinical proteinuria. A review of the literature also suggests that cyclophosphamide in combination with prednisone appears to be an effective therapeutic regimen for the glomerulonephritis of cryoglobulinemia. However, the correlation of clinical response and renal morphology in cryoglobulinemia has heretofore not been emphasized.

Biopsy↗
PubMed1982

The effects of airway pressure on cardiac function in intact dogs and man.

Ventilation with positive end-expiratory pressure (PEEP) is associated with reduced cardiac output, but the mechanisms involved are controversial. Possible explanations include increased intrathoracic pressure, reflex changes in myocardial inotropism, pulmonary vascular obstruction and abnormal ventricular interaction. Three types of conscious canine preparations were developed to examine simultaneously each of these factors during ventilation with PEEP. In addition, similar measurements were obtained in patients after cardiac surgical procedures and compared with the results of animal experiments. The primary cause of reduced cardiac output during PEEP appeared to be a diminished end-diastolic volume of the left ventricle, and this appeared to be the result of elevated intrathoracic pressure and increased impedance to blood flow through the lungs. Abnormal interventricular septal shifting and reflex autonomic alterations did not appear to be significant in the normal cardiovascular system. These data provide insight into the cardiac effects of PEEP and emphasize the importance of simultaneous quantification of biventricular performance when assessing cardiopulmonary function.

Animals↗
PubMed1982

Lyt phenotype of H-2b CTL effectors and precursors specific for the SV40 transplantation rejection antigen.

The immune effector cells mediating the in vitro immune response to the SV40 transplantation rejection antigen were characterized by using monoclonal antibody directed against lymphocyte differentiation (Lyt) antigens. Two distinct T lymphocyte populations were found to be responsible for the in vitro lysis of SV40-transformed cells, and Lyt 1+,2+ cytotoxic T lymphocyte (CTL) that is present in the spleens of SV40 immunized mice 9 days postimmunization and an Lyt 1-,2+ CTL that is generated by secondary in vitro stimulation of in vivo primed spleen cells. During secondary in vitro stimulation of SV40 immune spleen cells obtained 9 days postimmunization, a shift in the Lyt phenotype of the CTL from Lyt 1+,2+ to Lyt 1-,2+ is observed. Although the Lyt 1-,2+ CTL can be derived from Lyt 1-,2+ noncytotoxic memory cells, it is not known whether the Lyt 1+,2+ CTL differentiates into an Lyt 1-,2+ CTL during in vitro stimulation.

Antigens, Ly↗