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Biomedical subjects

G A Miller

Publications and source records attributed to G A Miller.

At least 145 records · Page 8Linked to original sources
PubMed1985

Percutaneous transluminal angioplasty vs. surgery for renovascular hypertension.

Therapeutic results in 102 hypertensive patients were evaluated after either renal artery percutaneous transluminal angioplasty (PTA) or surgical bypass procedures for renovascular hypertension. A minimum of 6 months of follow-up was accepted to evaluate therapeutic success or failure. Renal angioplasty had a beneficial result in each of 13 patients with fibromuscular dysplasia and in 10 (83%) of 12 patients with atherosclerotic lesions that did not involve the origin of the renal artery. Although surgery was also beneficial in each of six patients with fibromuscular dysplasia, it helped only five of 10 patients with atherosclerosis of the renal artery. Angioplasty results were similar to surgical results for atherosclerotic lesions that involved the origin of the renal artery. Angioplasty was unsuccessful in two cases of neurofibromatosis because of the firm nature of the lesions, where a bypass procedure was successful in one case. Major complications were more common in surgical cases than in angioplasty. PTA is recommended for all renal artery lesions; surgery should be reserved for failed PTA or recurrent renal artery stenosis after PTA.

Adolescent↗
PubMed1985

Percutaneous approach to nephrolithiasis.

Percutaneous techniques were successful in removing stones from 101 (92%) of 110 kidneys attempted. Ultrasonic lithotripsy was used on 80 kidneys in 74 patients with stones 5-38 mm in diameter. The most common complication was incomplete disintegration with retained stone fragments. Twenty patients were treated by direct stone extraction, either by a stone basket or forceps. The average hospitalization for percutaneous stone removal of 10 days was not significantly different from that for open nephrolithotomy. However, patients undergoing percutaneous stone removal had only a 3-10 day convalescence after hospital discharge before returning to normal activity.

Adolescent↗
PubMed1985

Intravenous digital subtraction angiography in the preoperative evaluation of renal masses.

Intravenous digital subtraction angiography (DSA) was performed in 23 patients with renal masses to document tumor extension into the main renal vein or inferior vena cava. The DSA findings were compared with computed tomographic as well as surgical and pathologic findings. Additional data regarding the number of renal arteries present and the relative vascularity of the tumor were also gathered. DSA documented 17 true-negative renal veins, three true-positive renal veins, and one false-negative renal vein. Two patients could not hold their breath long enough to evaluate the renal vein. In 17 of 19 cases, single renal arteries to the affected kidney were correctly identified. In three patients, two renal arteries to the involved kidney were correctly identified. The renal masses were avascular in two patients, hypovascular in five, moderately vascular in eight, and hypervascular in seven. In one case the mass was out of the field of view, and vascularity was not evaluated. In these patients, DSA was an accurate and relatively noninvasive method to assist in the preoperative evaluation of renal masses.

Adenocarcinoma↗
PubMed1985

Nitrous oxide: effective analgesic for vascular and interventional procedures.

During a 2 year period nitrous oxide was used as a sole or supplementary analgesic during 173 vascular or interventional procedures including peripheral angiography and endourologic and endobiliary procedures. The decision to administer nitrous oxide to a given patient was a matter of physician preference. Patients with bowel obstruction, pneumothorax, or chronic obstructive pulmonary disease were excluded from this method of analgesia. The nitrous oxide was administered by a radiology nurse under the supervision of an attending radiologist. Nitrous oxide was used without premedication for 39 procedures and with premedication (usually meperidine 1 mg/kg, promethazine 0.3 mg/kg, or atropine 0.01 mg/kg) in 134 procedures. In 74% of nonpremedicated individuals analgesia was adequate with nitrous oxide alone; 26% required supplemental intravenous medication. In 61% of premedicated individuals pain relief was adequate with nitrous oxide; 39% required supplemental intravenous medication. Complications, including nausea, vomiting, and agitation, occurred in eight patients, but were minor and easily reversed by decreasing the concentration of nitrous oxide. Nasally administered nitrous oxide is a safe, easily used, and effective analgesic.

Analgesics↗
PubMed1985

Humoral immune response of patients receiving specific active immunotherapy for renal cell carcinoma.

The object of this study was to characterize the antigens evoking an immune response in renal cell carcinoma (RCC) patients receiving specific active immunotherapy with irradiated autologous tumor cells and Corynebacterium parvum as adjuvant. Seventy serum samples from 11 patients with RCC undergoing specific active immunotherapy were evaluated. Fifty of the 70 serum specimens (71%) had immunoglobulin G antibody directed to autologous tumor cells. Absorption studies were completed on 4 patients (S.E., M.M., R.N., S.V.) with 2 patients (S.V. and M.M.) demonstrating reactivity to a RCC-associated antigen present on their autologous tumor cells. One patient's serum (R.N.) was absorbed not only with autologous tumor cells but also with an allogeneic RCC cell line. The fourth patient's (S. E.) serum reactivity was able to be absorbed only with autologous tumor cells and several, but not all, of the clones of that autologous cell line. Patient S.E. serum binding by clones of RCC cell line RPMI-SE was seen to vary from no ability to bind RPMI-SE in some clones to double the parental binding in others. Consistent with this finding was the demonstration that high serum-binding clones could absorb Patient S.E. serum reactivity to autologous RCC cells, while low binding clones could not. These data suggest a measure of heterogeneity among the parental RCC cell line, as demonstrated by its clones. This study has shown that the autologous tumor vaccine with adjuvant used here was an immunogenic therapeutic agent. The response mounted by these patients was a response to a RCC-associated antigen with the level of reactivity changing with the number of immunizations and disease status. Also suggested by this work is the possible primary tumor heterogeneity, as demonstrated by the differential reactivity seen among clones of a RCC cell line established from such a primary tumor.

Antibody Formation↗
PubMed1984

Percutaneous transluminal angioplasty in diabetic patients: an effective treatment modality.

Percutaneous transluminal angioplasty (PTA) was performed for nonhealing ulcers, severe claudication, or rest pain in 10 patients with diabetes mellitus. Twenty-two atherosclerotic lesions were dilated in 15 extremities, including 16 iliofemoral arteries and 6 superficial femoral arteries. The procedure was technically successful in all patients and 8 of 9 (89%) with clinical follow-up showed improvement clinically after the procedure. Diabetes is not a contraindication to PTA; rather this modality can be used effectively to control and treat peripheral vascular insufficiency in diabetic patients.

Aged↗
PubMed1984

CT differentiation of thoracic aortic aneurysms from pulmonary masses adjacent to the mediastinum.

Paramediastinal masses adjacent to the aorta require a diagnostic evaluation to differentiate between tumor and aneurysm. It has been suggested that neoplasm may enhance sufficiently to be confused with a vascular structure or that a clot filled aneurysm may simulate a neoplasm by not filling with contrast medium. Five patients, two with thoracic aneurysms, two with malignancy, and one with a malignancy and an aortic dissection, are presented in whom bolus injection computed tomography (CT) was able to distinguish between aneurysm and mass. The CT examination also accurately visualized the point of communication of the aneurysm with the aorta, defined the relationship of the aneurysm to vital mediastinal structures for planning surgical resection, and helped plan the approach for percutaneous transthoracic needle aspiration when tumor was suspected. Bolus injection CT represents a rational alternative to aortography for mediastinal paraaortic masses.

Adult↗
PubMed1984

The presentation of symptomatic heart disease in infancy based on 10 years' experience (1973-82). Implications for the provision of services.

The diagnoses and age at presentation of 1665 infants with symptomatic heart disease, who were admitted to the Brompton Hospital, London, during the period 1973-82 were reviewed. The frequency of certain conditions had changed during the period of the study. Complete transposition of the great arteries and critical aortic stenosis had become less common, whereas the frequency of right ventricular outflow tract obstruction, and of critical pulmonary stenosis in particular, had increased. Several conditions, including coarctation of the aorta, hearts with univentricular-atrioventricular connexion, and double outlet ventricle, formed a higher proportion of cases in the present series than in the New England Regional Infant Cardiac Program study, whereas the proportion of cases of atrial septal defect, hypoplastic left heart syndrome, and pulmonary atresia with intact septum was smaller. Most of the cyanotic infants presented during the first 14 days of life at the time of ductal closure. As expected this was also true of other duct dependent circulatory disorders such as aortic coarctation and interrupted aortic arch. Acyanotic infants with potentially large left to right shunts tended to present during the second month of life, when the pulmonary vascular resistance fell. This study emphasises that most symptomatic infants with heart disease present during the first two months of life. As a consequence the provision of expert neonatal and infant medical services is an integral part of any paediatric cardiac service.

Age Factors↗
PubMed1984

Relationships between beat-to-beat interval and the strength of contraction in the healthy and diseased human heart.

Twenty-six adult patients, classified by clinical and catheter criteria into groups of those with normal and abnormal left ventricular function, were studied during cardiac catheterization. Right heart pacing was established, and left ventricular dP/dt was measured with end-catheter manometers. By varying the interval preceding a test beat after periods of steady pacing it was confirmed that recovery of left ventricular mechanical function (maximum dP/dt) occurs approximately 800 msec (optimum interval) after a beat. The augmentation of maximum dP/dt of the first 2 beats after an extrasystole, each spaced at the optimum interval, was also studied; the amount of potentiation was varied by alterations in extrasystolic interval. Potentiation decayed from the first to the second postextrasystolic beat with a ratio that was fixed in each individual patient. The ratio (recirculation fraction) was higher in patients with normal than in those with abnormal left ventricular function (mean +/- SD 0.52 +/- 0.10 vs 0.37 +/- 0.11, p less than .005). There was an inverse relationship between this ratio and the degree of potentiation of the first postextrasystolic beat (r = .80, p less than .001). We postulate a disturbance of excitation-contraction coupling mechanisms to explain these effects.

Adult↗
PubMed1984

Ventilation-perfusion scanning and pulmonary angiography: correlation in clinical high-probability pulmonary embolism.

During a 3-year period, 173 clinically selected patients underwent pulmonary angiography to confirm or exclude acute pulmonary embolism. All patients had undergone ventilation-perfusion (V/Q) scanning (167 patients) or perfusion scanning alone (six) before angiography. Angiography was done because the results of the V/Q scanning did not satisfy the clinician's needs for certainty. The results of the V/Q and studies were compared to determine the relative accuracy of V/Q scanning in this clinical setting. Pulmonary embolism was found in seven (15%) of 47 patients with low-probability scans, 11 (32%) of 34 patients with intermediate-probability scans, 22 (39%) of 57 patients with indeterminate scans, and 23 (66%) of 35 patients with high-probability scans. In this clinically selected population, low-probability scans were more accurate in excluding pulmonary embolism than were high-probability scans in establishing that diagnosis.

Humans↗
PubMed1983

Aortic catheterisation via percutaneous left ventricular puncture.

When retrograde catheterisation and angiography of the ascending aorta from the brachial or femoral approach is not possible, this can be accomplished by direct percutaneous left ventricular puncture. The haemodynamic and angiographic information obtained was essential to surgical correction of aortic arch anomalies as illustrated in two patients.

Adult↗