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Biomedical subjects

A R Graham

Publications and source records attributed to A R Graham.

At least 55 records · Page 3Linked to original sources
PubMed1987

Closed chest catheter desiccation of the atrioventricular junction using radiofrequency energy--a new method of catheter ablation.

Closed chest catheter ablation of the atrioventricular (AV) junction has been performed with direct current or laser energy. The effect of 750 kHz radiofrequency energy on ablation of the AV junction was evaluated in 13 dogs. The radiofrequency energy was generated from an electrosurgical generator in the bipolar mode. The radiofrequency output was delivered between two distal electrodes (bipolar ablation) in eight dogs, and between the distal electrode and an external patch electrode (unipolar ablation) in another five dogs at varying power (watts) but with a constant pulse duration of 10 seconds. Complete AV block was achieved in 11 dogs and second degree AV block in 2. During the 4 to 7 day follow-up period, complete AV block persisted in 9 of the 11 dogs with initial complete heart block. The other two had return of AV conduction; one had persistent 2:1 AV block and the other had persistent first degree AV block. Of the two dogs with initial second degree AV block, one developed complete AV block, the other had resumption of 1:1 AV conduction with a normal PR interval. Energy was delivered in 1 to 13 applications per dog. One hundred to 700 J per application was delivered with bipolar ablation and 10 to 100 J with unipolar ablation. There was no damage to the catheter unless the catheter was repeatedly used in excess of 1,500 J of total energy. Ventricular arrhythmias were not observed. Pathologic examination showed well delineated coagulation necrosis at the AV junction without surrounding hemorrhage or mural thrombus. Microscopic findings consisted of necrosis with cell infiltration in the periphery of necrosis. Most injuries involved the AV node, the approaches to the AV node and the penetrating bundle. In conclusion, catheter ablation of the AV junction with radiofrequency energy is safe. It can effectively induce discrete areas of necrosis and produce various degrees of AV block. In addition, ablation by radiofrequency energy has distinct advantages as compared with catheter ablation with direct current or laser energy.

Animals↗
PubMed1987

Duodenal obstruction following abdominal aortic reconstruction.

Four patients developed duodenal obstruction after 161 abdominal aortic reconstructions, an incidence (2.5%) rivaling that of graft infection and arterioenteric fistula. The diagnosis is easily confirmed by gastrointestinal contrast studies. Duodenal obstruction is usually caused by perigraft collagenous adhesions and is probably less likely to occur if the mobilized duodenum is not replaced directly over the aorta during resuture of the retroperitoneum. Undetected duodenal obstruction leads to rapid dehydration and electrolyte and caloric depletion.

Aged↗
PubMed1987

Antinuclear antibodies and survival in cardiac transplant patients.

Serum from 48 patients with cardiac transplants was tested for the presence of antinuclear antibodies (ANA). Thirty-two of the sera were negative for ANA (ANA-), and 16 were positive for ANA (ANA+). Six of the ANA+ sera had a diffuse pattern, six had a peripheral pattern, three had a combined diffuse and rim pattern, and one had a diffuse and nucleolar pattern. Seven of the ANA+ sera were positive at a 1:40 titer, one at a 1:80 titer, four at a 1:160 titer, two at a 1:320 titer, and two at a 1:640 titer. Thirteen of the 32 ANA- patients have died, at intervals of one month to four years after transplantation. Fourteen of the 16 ANA+ patients have died, at intervals ranging from less than one day to four years after transplantation. The mean time period from transplantation to death was 13 +/- 15 months for the ANA+ patients: these were not statistically significantly different. However, the mean interval from transplantation to death of the ANA+ patients with an ANA titer greater than 1:40 was 0.8 +/- 0.8 months, which was significantly different from the mean survival period of the ANA+ group as a whole (P less than or equal to 0.05) and the mean survival of the ANA- group (P less than or equal to 0.005). Although the mechanism is not clear, there appears to be an association between higher titer serum ANA positivity and increased mortality in patients with cardiac transplants with significantly decreased duration of survival after transplantation.

Adolescent↗
PubMed1987

Detection of diagnostic clues in statistical histometry.

Examples are given of the detection of diagnostic clues in quantitative cytology and histopathology by statistical testing, such as may be applied in image analytical procedures. Schematic and other examples are presented of the visual images analyzed by each procedure, whose limits are also discussed. The situations analyzed include increased cellularity, differences in nuclear placement patterns, uniformity of displacement, variance in nuclear diameters and chaincode variance of nuclear placement. A specific model is presented for describing or generating a series of dependent observations representing nuclear placement, based on the Box-Jenkins (ARIMA) models for decomposing a spatial or temporal series into several components. This model describes the statistical observations that are random samples from the series. Finally, one graphic example is given in which visual inspection more readily ascertains an alteration than does statistical analysis of a modest-sized sample.

Analysis of Variance↗
PubMed1987

Carotid endarterectomy, siphon stenosis, collateral hemispheric pressure, and perioperative cerebral infarction.

To determine whether moderate stenosis (50% to 80%) of the intracranial segment of the internal carotid artery increases the risk of cerebral infarction after carotid endarterectomy, the arteriograms, ocular pneumoplethysmograms, internal carotid back pressure, and clinical outcome after 169 operations were reviewed. Siphon stenoses less than 50% were not included because of their doubtful anatomic and hemodynamic significance. No patients with stenosis greater than 80% underwent operation. Moderate siphon stenosis affected 37 vessels, 24 (14.2%) ipsilateral and 13 (7.6%) contralateral to the side of operation. Eight patients had bilateral siphon stenosis. Three patients had stroke after operation; none of these cases had siphon stenosis. Moderate siphon stenosis did not increase the risk of perioperative cerebral infarction. Stroke only occurred in those patients in whom there was arteriographic or functional evidence that the affected hemisphere was isolated from effective collateral vessels.

Adult↗
PubMed1987

Morphometry in surgical pathology.

The potential role of morphometry in surgical pathology is discussed. Specific areas in which morphometry could be helpful are in (1) identifying malignant cells in lesions that are largely composed of benign-appearing cells (e.g., follicular thyroid neoplasms), (2) defining reference points in apparent continua (e.g., in the progression from normal colon to adenoma to adenocarcinoma), (3) distinguishing between benign and malignant lesions with similar appearances (e.g., fibromatosis and fibrosarcoma of the soft tissue) and (4) distinguishing between similar-appearing types of malignant neoplasms (e.g., between small-cell carcinoma of the lung and small-cell lymphoma). Morphometric techniques are already being used in DNA ploidy determinations, which frequently bear prognostic information. The measurement of other nuclear and cellular parameters has been used for both diagnostic and prognostic ends; one example is the relation of nuclear roundness to metastatic potential in prostatic carcinomas. Morphometry is now being increasingly applied to histologic sections, as in the prognostic study of lesion thickness in malignant melanoma and the diagnostic study of glandular architecture in colonic adenoma. The use of morphometry can enhance the observation and interpretation of morphologic features, which, combined with the clinical data and the experience of the pathologist, can lead to greater accuracy and precision in surgical pathology diagnoses.

Cytodiagnosis↗
PubMed1986

Intravesical bacillus Calmette-Guerin therapy and associated granulomatous renal masses.

We report a case of clinically symptomatic renal granulomas occurring during intravesical and intracutaneous bacillus Calmette-Guerin therapy for bladder cancer. The patient responded to antituberculous triple therapy. We emphasize the rarity of such extravesical infectious complications and discuss the possible routes of renal inoculation.

Biological Products↗
PubMed1986

Immunosuppressive therapy and plasmapheresis in rapidly progressive glomerulonephritis associated with bacterial endocarditis.

A 25-year-old male presented with new cardiac murmurs and acute renal insufficiency. Blood cultures grew Streptococcus viridans and appropriate antibiotic therapy was initiated. A renal biopsy revealed diffuse proliferative glomerulonephritis with crescents involving more than 50% of the glomeruli. Treatment with antibiotics, plasmapheresis, and steroids resulted in renal recovery that paralleled reductions in circulating immune complexes. The rationale for this therapeutic approach is discussed, as well as a review of two similar case reports. These experiences suggest a possible role for plasmapheresis and immunosuppressive drugs in patients who develop rapidly progressive glomerulonephritis as a complication of bacterial endocarditis.

Adult↗
PubMed1986

Rationale for simultaneous carotid endarterectomy and aortocoronary bypass.

Seventy-eight patients were treated for coexistent carotid and coronary stenosis by simultaneous reconstructions. Five patients died (6.4%), one from a stroke contralateral to the carotid reconstruction. Four others suffered a perioperative stroke (total stroke incidence 6.4%). Three myocardial infarctions occurred (3.8%) including one fatal infarct. Analysis of the most recent 36 combined reconstructions indicates that the extramorbidity in this group increased the stroke or death rate for all carotid endarterectomies carried out in the same period by only 1%. Alternatively if these patients had been operated upon by aortocoronary grafting alone the mortality would have increased by 0.1% assuming no neurologic complications. Since these 36 patients had severe carotid stenosis and would have been refused carotid endarterectomy as an isolated procedure the results seem better than would have been achieved by staged operations.

Adult↗
PubMed1986

The validity of internal carotid back pressure measurements during carotid endarterectomy for unilateral carotid stenosis.

Peri-operative neurological deficits in 212 patients undergoing carotid endarterectomy for unilateral carotid stenosis were examined to determine whether the internal carotid back pressure (ICBP) correctly predicted the need for a protective shunt during temporary carotid occlusion. Three strokes occurred in 149 patients who were not shunted. In one of these the ICBP indicated the need for a shunt, but shunting was not possible for technical reasons and a stroke due to hypoperfusion occurred. In another patient a stroke occurred as a result of embolism. There was only one patient where the ICBP possibly incorrectly predicted that a shunt would not be necessary. Four strokes due to various causes occurred in the 63 shunted patients. Shunting was not withheld from these patients in order to prove that ICBP would correctly predict their vulnerability to hypoperfusion since to have done so would be unethical. The results indicate that in patients with unilateral carotid stenosis the ICBP is an accurate indicator of which patients can undergo carotid endarterectomy without the need for shunting.

Aged↗
PubMed1986

Fibrolamellar carcinoma of liver: a primary malignant oncocytic carcinoid?

Immunohistochemical and ultrastructural findings in two cases of fibrolamellar carcinoma of the liver and two cases of hepatocellular carcinoma of the common histologic type are described. Ultrastructural examination of both cases of fibrolamellar carcinoma revealed the presence of neurosecretory (NS) granules which were sparse in some cells and abundant in others. Many of the tumor cells had a distinct oncocytic appearance with abundant mitochondria. A portion of the glutaraldehyde-fixed neoplasm was processed for the uranaffin reaction (an ultrastructural cytochemical stain specific for the NS granules of neuroendocrine tissue). Abundant uranaffin-positive granules were found in the neoplastic cells of both cases of fibrolamellar carcinoma, whereas no uranaffin-positive granules were found in hepatocellular carcinoma of the common histologic type. There was no statistical difference in the mean diameter of the uranaffin-positive granules measured from both cases. Immunohistochemistry revealed the presence of neuron-specific enolase (NSE) and serotonin in one of the two cases of fibrolamellar carcinoma and no NSE staining in two cases of hepatocellular carcinoma of the common histologic type. These findings suggest that some liver tumors presenting histologically as fibrolamellar carcinoma may be neuroendocrine in nature.

Adult↗
PubMed1985

Direct immunofluorescence findings in peripheral nerve from patients with diabetic neuropathy.

Direct immunofluorescence examination was performed on peripheral nerve from 16 patients with diabetes mellitus and 53 additional patients with peripheral neuropathy of diverse cause. Six nerves from patients with diabetes mellitus yielded positive findings: 4 had granular and lamellar deposition of IgM within the perineurium (of which 2 also had fibrinogen, IgA, C3, and albumin and 1 also had IgG); 1 had IgM, C3, and C4, and perineurial fibrinogen; the sixth contained linear perineurial C3 and fibrinogen. These 6 nerves contained axonal degeneration (3), axonal degeneration with chronic demyelination (1), microvasculitis with wallerian degeneration (1), and no pathological change (1). Sixteen of 53 nerves from nondiabetics yielded positive findings with immunofluorescence, possibly as a result of vascular leakage or as a manifestation of impaired removal of plasma proteins. The deposition of immunoreactants, as well as other plasma proteins, in peripheral nerve from patients with diabetes mellitus probably represents a "trapping" phenomenon reflecting altered basement membrane permeability. Alternatively, the changes could reflect a defect in the blood-nerve barrier in diabetic microangiopathy.

Adolescent↗
PubMed1985

Benign mediastinal teratoma with immature elements exhibited clonal growth and motility in the human tumor clonogenic assay.

The human tumor clonogenic assay has been used to study the growth and drug sensitivity of a wide variety of malignant and a limited number of benign tumors. We conducted detailed studies on a multipotential benign teratoma from a young child that gave rise to colonies in soft agar culture. The colonies separated themselves from the surrounding agar and exhibited rapid rotary movement (15 r/min). Morphologic, ultrastructural, and immunologic studies showed the colonies to be comprised exclusively of ciliated respiratory epithelium. The uniform beating of the cilia resulted in a constant rolling motion of the colonies in a single direction.

Cell Differentiation↗
PubMed1985

Fluorescence of damaged myocardium in endomyocardial biopsy specimens for the evaluation of cardiac transplantation.

Sections stained with hematoxylin-eosin from 138 endomyocardial biopsy specimens were examined in a Zeiss epifluorescent ultraviolet microscope for fluorescence indicative of myocardial injury. The biopsy specimens had been obtained from cardiac transplant recipients for routine follow-up evaluation or due to clinically suspected episodes of rejection. Yellow fluorescence and/or granularity of necrotic myofibers (with normal myocardium appearing olive green to yellow-brown), as reported in autopsy series, was observed in 22 of our specimens, for which the results of staining with hematoxylin-eosin and/or trichrome were found to contain areas of fiber fluorescence that were not recognized by staining with hematoxylin-eosin or trichrome. In some areas in an additional 13 specimens, the fiber damage seen on ultraviolet examination was greater than that suspected on the basis of the light microscopic morphologic changes. In seven cases routine light microscopy revealed fiber necrosis that could not be confirmed by ultraviolet illumination study. Fluorescence of damaged myofibers under ultraviolet illumination may contribute to the detection of early or mild myocardial injury in endomyocardial biopsy specimens from cardiac transplant recipients.

Biopsy↗
PubMed1985

Combined carotid coronary reconstructions--synchronous or sequential?

Analysis of 16 synchronous with 26 sequential combined carotid coronary reconstructions showed no statistical advantage of either approach. Sequential operations are more convenient but increase the total operating time by an hour or so. Synchronous operations can be carried out without carotid shunting despite hypotension provided hypothermia is established. In other circumstances the internal carotid back pressure is used to indicate the need for carotid shunting. In the 42 patients there were three strokes (7%) including one fatal stroke (2%) and two myocardial infarctions, both fatal (5%).

Cardiopulmonary Bypass↗
PubMed1985

Statistical histometry in the diagnostic assessment of tissue sections.

A statistical histometric model to distinguish adenoma of the colon from normal colon is described. The model, based on the number and location of glandular nuclei, with a dependency scheme based upon displacement, was tested and shown to be significant and capable of simulating the architecture of an adenoma.

Adenoma↗