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Biomedical subjects

M Sanders

Publications and source records attributed to M Sanders.

At least 109 records · Page 6Linked to original sources
PubMed1990

Design and performance of POSICAM 6.5 BGO positron camera.

A high-resolution, whole-body positron camera, POSICAM 6.5 BGO, has been designed, built, and tested; results from it are presented. The camera utilizes 1,320 BGO crystals and 720 PMTS in a staggered geometry to produce high resolution of 5.8 mm FWHM and 21 image planes simultaneously. The axial resolution of the camera is measured at 11.9 mm at the center. High axial sampling is achieved with 5.125 mm separation of the image planes such that three-dimensional imaging of an object can be carried out in a single scan. Recovery of volumetric distribution of radioactivity and object dimensions in axial and sagittal views is demonstrated by imaging spherical objects 13 mm to 39 mm in diameter.

Equipment Design↗
PubMed1989

Respiratory sinus arrhythmia in the denervated human heart.

We performed this study to test whether the denervated human heart has the ability to manifest respiratory sinus arrhythmia (RSA). With the use of a highly sensitive spectral analysis technique (cross correlation) to define beat-to-beat coupling between respiratory frequency and heart rate period (R-R) and hence RSA, we compared the effects of patterned breathing at defined respiratory frequency and tidal volumes (VT), Valsalva and Mueller maneuvers, single deep breaths, and unpatterned spontaneous breathing on RSA in 12 normal volunteers and 8 cardiac allograft transplant recipients. In normal subjects R-R changes closely followed changes in respiratory frequency (P less than 0.001) but were little affected by changes in VT. On the R-R spectrum, an oscillation peak synchronous with respiration was found in heart transplant patients. However, the average magnitude of the respiration-related oscillations was 1.7-7.9% that seen in normal subjects and was proportionally more influenced by changes in VT. Changes in R-R induced by Valsalva and Mueller maneuvers were 3.8 and 4.9% of those seen in normal subjects, respectively, whereas changes in R-R induced by single deep breaths were 14.3% of those seen in normal subjects. The magnitude of RSA was not related to time since the heart transplantation, neither was it related to patient age or sex. Thus the heart has the intrinsic ability to vary heart rate in synchrony with ventilation, consistent with the hypothesis that changes, or rate of changes, in myocardial wall stretch might alter intrinsic heart rate independent of autonomic tone.

Adult↗
PubMed1988

Malignant extraovarian endometriosis: two case reports and review of the literature.

Two cases of adenocarcinoma arising in extraovarian endometriosis 19 and 8 years following abdominal hysterectomy and bilateral salpingo-oophorectomy are described. Both patients presented with hydronephrosis. One had been on chronic estrogen therapy. The literature is reviewed in reference to frequency, tumor type, and sites of occurrence.

Adenocarcinoma↗
PubMed1988

Conservative management of herniated nucleus pulposes: treatment approaches.

Herniated nucleus pulposus (HNP) is a significant cause of physical impairment to the afflicted individual and a major factor in a wide range of socioeconomic issues. This paper examines various disc herniation therapies and compares conservative treatment modes with surgical intervention. Results of a 10-yr study are reviewed and recommendations are made concerning conservative treatment management in the physician's office and at home, return-to-work considerations, preventive care and the importance of cooperation among patient, physician, employer and third-party provider. The authors conclude that conservative treatment is an acceptable, cost-effect alternative to surgery.

Humans↗
PubMed1987

Influence of the extent of resection on survival after curative treatment of gastric carcinoma. A retrospective multivariate analysis.

The therapeutic value of extensive gastric resection and regional lymphadenectomy in the curative treatment of gastric adenocarcinoma is controversial. We undertook a retrospective study of 210 patients treated with curative intent from 1960 to 1980. A multivariate survival analysis using the Cox model revealed five significant variables predictive of death from gastric cancer--two inherent pathologic factors: (1) nonpyloric site and (2) metastases in more than three lymph nodes, and three treatment factors that could often be controlled by the surgeon: (3) microscopic positive gastric resection margin, (4) inadequate lymphadenectomy, and (5) total gastrectomy. These observations reaffirm the value of wide gastric resection and adequate lymphadenectomy but argue against a general policy of elective total gastrectomy in the curative treatment of gastric carcinoma.

Adenocarcinoma↗
PubMed1987

Trauma and amyotrophic lateral sclerosis: a report of 78 patients.

This was a controlled study to assess the possible role of mechanical trauma in the pathogenesis of some cases of amyotrophic lateral sclerosis (ALS). Questionnaires were sent to 181 patients with ALS who had developed the disease before age 45. Among the 135 respondents 78 (58%) reported having sustained injuries severe enough to have required medical attention prior to the onset of their motor neuron illness. Fifty nine (76%) of the ALS patients reporting an earlier trauma had incurred an injury to the head, neck, shoulder and/or arm. For controls, we used the 85 patients with multiple sclerosis who responded to the questionnaires sent them. The findings of this investigation add further evidence that a former injury may be important in the etiology of some cases of ALS developing early in life.

Adult↗
PubMed1987

Immunoaffinity purification of S-antigen using monoclonal antibodies to different antigenic sites.

Retinal S-antigen (S-ag) was purified by monoclonal antibody (MoAb) immunoaffinity chromatography from soluble protein extracts of bovine and human retina. Purification of S-ag was readily achieved by affinity chromatography using four different MoAb-Sepharose 4B columns. The four antibody columns gave different recoveries with material of comparable enrichment with greater than 95% purity as judged by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The use of two different MoAbs covalently bound to Sepharose 4B and known to be directed to disparate, spacially distant epitopes on S-ag led to at least a twofold increase in recovery, with the aforementioned purity. Immunoaffinity purified S-ag retained its serological and uveitogenic properties. The high recovery of S-ag associated with this one-step procedure is preferable to conventional preparatory techniques, and enables high antigen recovery when tissue availability is limited (eg human retina).

Antibodies, Monoclonal↗
PubMed1986

Renin in angiolymphoid hyperplasia with eosinophilia. Its possible effect on vascular proliferation.

A hypertensive man became normotensive after the surgical removal of two subcutaneous masses of angiolymphoid hyperplasia with eosinophilia. To demonstrate that angiolymphoid hyperplasia with eosinophilia is a renin-producing pathologic condition, Bowie stain for juxtaglomerular cell granules and immunohistochemistry for human renin were used. Bowie stain was positive in cells showing cytoplasmic granules similar to those found in the juxtaglomerular cells of the kidney. Immunohistochemical staining using antiserum against human renin showed the presence of renin-containing cells. This staining was not seen after substitution of the specific renin antiserum by preimmune serum, by the renin antiserum preabsorbed with pure human renin, or with plasma from a patient with high-plasma renin activity. Renin-containing cells were located in areas surrounding vascular structures and were apparently neither endothelial, mast, nor lymphoid cells. Six of eight additional cases of angiolymphoid hyperplasia with eosinophilia were positive for renin-containing cells. Renin has been described in several other histologically highly vascularized tumors. Since a product of renin, angiotensin II, has been found to have angiogenic properties, it is possible to postulate that renin, through angiotensin II, may stimulate the proliferation of vessels and, therefore, may be involved in the pathogenesis of angiolymphoid hyperplasia with eosinophilia.

Abdominal Muscles↗
PubMed1985

Angiographic changes thirty minutes following percutaneous transluminal coronary angioplasty.

In order to ascertain whether coronary angiography performed immediately after the completion of successful percutaneous transluminal coronary angioplasty (PTCA) can be used as an index of the final outcome of the procedure, angiography was repeated thirty minutes post PTCA in twenty consecutive patients undergoing elective PTCA. Comparison of the pre PTCA, immediate post PTCA and thirty minutes post PTCA angiograms showed that the initial angiographic success of 77.8% improvement in lumen diameter from pre PTCA to immediate post PTCA was reduced by 16.2% to 61.6% thirty minutes later. We conclude that angiographic changes continue to occur in the immediate post PTCA period and that the immediate post PTCA angiogram may not represent the true outcome of the procedure.

Adult↗
PubMed1985

Efficacy of percutaneous transluminal coronary angioplasty compared with single-vessel bypass.

The use of percutaneous transluminal coronary angioplasty has been increasing rapidly. When the procedure is successful, the clinical relief of symptoms is similar to that achieved with direct coronary artery bypass. It has been suggested that the angioplasty procedure, however, can accomplish these results with potentially less morbidity and mortality, along with a shorter hospital stay. In order to evaluate the results of percutaneous transluminal coronary angioplasty with single-vessel coronary artery bypass, we performed a retrospective review. From January, 1982, to December, 1983, a total of 198 angioplasty procedures were performed. They were successful in 142 patients (71.7%). Emergency bypass was performed in 21 (10.6%) of the 56 patients who had undergone unsuccessful angioplasty procedures. Perioperative myocardial infarction occurred in eight of these patients (38.1%). There were no operative deaths, but there was one death after angioplasty. Elective bypass was performed in 28 of the patients who had angioplasty procedures, with no perioperative myocardial infarctions or operative deaths. Recurrent symptoms developed in 31 (21.8%) of the 142 patients who had undergone initially successful angioplasty. From 1982 to 1983, single-vessel bypass was performed in 143 patients. The internal mammary artery was utilized in 102 patients and the autogenous saphenous vein in 41 patients. There were no perioperative myocardial infarctions or deaths. No patients developed recurrent symptoms during the study interval. Percutaneous transluminal coronary angioplasty is an acceptable alternative to coronary artery bypass in patients with localized lesions that are sufficiently serious to cause symptoms and warrant surgical bypass. However, the angioplasty procedure, when compared to single-vessel coronary artery bypass, may result in an increased incidence of acute myocardial infarction and in a significantly (p less than 0.001) increased incidence of early recurrence of symptoms.

Adult↗
PubMed1984

Distal coronary power injection during percutaneous transluminal coronary angioplasty.

A modification of the standard percutaneous transluminal coronary angioplasty (PTCA) procedure is described using a power injector instead of a hand-held syringe for distal coronary contrast injections. This system was used in 215 dilatations without complications related to the power injector. We found this system to simplify the PTCA procedure and allowed for improved distal visualization even with the steerable PTCA catheters containing an intraluminal guide wire.

Angioplasty, Balloon↗
PubMed1984

Methemoglobin levels produced by organic nitrates in patients with coronary artery disease.

To determine if ordinary doses of nitrates produce a significant increase in methemoglobin, methemoglobin levels were measured in 59 randomly selected patients with coronary artery disease and unstable angina pectoris who were receiving organic nitrate therapy. Patients were taking isosorbide dinitrate, 2% nitroglycerin ointment, or a combination of the two. Patients were subdivided according to whether they were using one (group A) or more than one (group B) organic nitrate preparations. These results were compared with 17 control patients. Mean methemoglobin levels in group B were 1.78 +/- 1.29%, and this differed significantly (P less than 0.05) from both group A mean methemoglobin, 1.13 +/- 0.92%, and controls, 0.99 +/- 0.55%. The proportion of patients with elevated methemoglobin concentration increased from the control to group A to group B. It is concluded that commonly used dosages of nitrates are capable of causing elevations of methemoglobin which are probably not of routine clinical significance. However, these elevations may be of import in certain patient populations such as those with coronary insufficiency or anemia.

Aged↗
PubMed1984

Effects of NaHCO3, alpha-, and beta-adrenergic blockade on albuminuria after swimming in splenectomized dogs.

The albuminuria occurring after swimming in splenectomized dogs was investigated. Swimming in splenectomized dogs induces metabolic acidosis, a decrease in renal vascular conductance, and an increase in plasma renin activity, all three factors possibly implicated in the occurrence of albuminuria. The administration of sodium bicarbonate prior to swimming reduced the magnitude of the acidosis and eliminated the increase in albuminuria after swimming. Phenoxybenzamine, an alpha-adrenergic blocking agent that maintains the renal blood flow during exercise also blocked the increase in albuminuria despite a decrease of blood pH during swimming. However, after metoprolol, a beta 1-adrenergic blocking agent that blocks the rise in plasma renin activity during exercise, swimming causes a threefold increase in albuminuria (P less than 0.01). The albuminuric response to swimming preceded by saline was also significant (P less than 0.05). It is likely that post-swimming albuminuria in splenectomized dogs is linked to the decrease of renal vascular conductance or to the decrease in blood pH rather than to the rise in plasma renin activity.

Acidosis↗
PubMed1984

Proteinuria in intact and splenectomized dogs after running and swimming.

The occurrence of post-exercise proteinuria was investigated in intact and splenectomized dogs after treadmill running and swimming and compared to control experiments. Albumin and lysozyme were measured by radial diffusion. Urinary protein was analyzed by SDS-polyacrylamide gel electrophoresis. Swimming in the splenectomized dogs increased the albumin excretion in the first 30 min after exercise from 0.03 to 0.22 mg X min-1 and the lysozyme excretion in the same period from 0.11 to 0.75 micrograms X min-1. Swimming in intact dogs caused smaller increase in the lysozyme and albumin excretions during the exercise period itself as well as in the albumin excretion in the first 30 min after exercise. Running had no effect on urinary albumin or lysozyme but increased the low molecular weight protein fraction in the splenectomized dogs. Plasma lactate concentrations were higher during swimming in the splenectomized dogs than in the intact dogs. Possible mechanisms of post-exercise proteinuria are discussed.

Animals↗