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Biomedical subjects

M A Golden

Publications and source records attributed to M A Golden.

49 records · Page 3Linked to original sources
PubMed1992

Magnetic resonance angiography of peripheral runoff vessels.

Recent improvements in magnetic resonance imaging techniques have made magnetic resonance angiography (MRA) a very useful adjunct to invasive angiography. Fifty-five limbs in 51 patients with occlusive peripheral vascular disease were studied with both MRA and contrast arteriography. The magnetic resonance and contrast arteriograms were read by radiologists and surgeons and separate interventional plans were based on each study. The MRA findings differed significantly from those of conventional arteriography in 26 limbs (48%). In every case MRA visualized all of the same vessels and hemodynamic stenoses seen on the contrast arteriogram. In 48% of the cases, however, MRA revealed additional findings. Thus the discrepancies in the two studies were always the result of the failure of the arteriogram to reveal all of the patent vessels seen on MRA. The additional information provided by MRA resulted in alteration of the interventional plan in 11 cases (22%). In nine cases (18%) target vessels suitable for use in a limb-salvage procedure were identified by MRA, although they had been missed by conventional arteriography. In all of these cases, intraoperative arteriograms confirmed the suitability of these vessels for use in technically successful bypass procedures. In two cases (4%) additional information provided by MRA identified a target runoff vessel for bypass grafting that proved to be a better alternative than the one that would have been chosen on the basis of contrast arteriography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Evolving experience with thoracoabdominal aortic aneurysm repair at a single institution.

Fifty-seven patients underwent repair of atherosclerotic thoracoabdominal aortic aneurysms between 1978 and 1990. Five patients had urgent surgery for rupture. The 30-day operative mortality rate for the entire group was 18% (10 patients). Before July 1987, 19 patients (group 1) were operated on by use of a technique previously described. In these earlier patients the peritoneum was routinely entered, the diaphragm was divided radially, and no heparin was given. Among patients in group 1 there was a 30-day operative mortality rate of 42% (8 patients), and morbidity included myocardial infarction 4 (21%), respiratory failure 9 (47%), renal failure 12 (63%), bleeding requiring reoperation 4 (21%), and intestinal ischemia 3 (16%). Since July 1987 a standardized approach to all elective thoracoabdominal aortic aneurysms has been used in 38 patients (group 2). This method uses a left thoracoabdominal incision, circumferential division of the hemidiaphragm, retronephric totally extraperitoneal aortic exposure, single lung anesthesia, full heparinization, the graft inclusion technique, and liberal use of visceral endarterectomy. Patients in group 2 sustained a 30-day operative mortality rate of 5% (2 patients) and morbidity included myocardial infarction 2 (5%), respiratory failure 10 (26%), renal failure 11 (29%), bleeding requiring reoperation 1 (3%), paraplegia 6 (16%), and paraparesis 4 (11%). Modern surgery for repair of thoracoabdominal aortic aneurysm results in acceptably low operative mortality rates. Spinal cord ischemia remains an unresolved source of morbidity.

Aged↗
PubMed1991

Platelet-derived growth factor activity and mRNA expression in healing vascular grafts in baboons. Association in vivo of platelet-derived growth factor mRNA and protein with cellular proliferation.

In a baboon graft model of arterial intimal thickening, smooth muscle cells (SMC) have been observed to proliferate underneath an intact monolayer of endothelium and in the absence of platelet adherence. Because platelets are not present and therefore cannot be a major source of growth stimulus, we have proposed that the vascular wall cells in the graft intima express mitogens and regulate SMC proliferation. To test this hypothesis, we assayed the grafts for mitogenic activity and expression of growth factor genes. Segments of healing graft and of normal artery, when perfused ex vivo, released mitogenic activity into the perfusate. The graft released more mitogen than the normal arterial segment, and some of the activity was inhibitable with an antibody to human platelet-derived growth factor (PDGF). In addition, Northern analysis of total RNA demonstrated higher expression of PDGF-A chain mRNA in the graft intima compared to normal artery. PDGF-B chain mRNA was barely detectable in both tissues. PDGF mRNA levels within the graft interstices were not measured. In situ hybridization of 7.5- or 12-wk grafts indicated that some luminal endothelial cells and adjacent intimal SMC contained PDGF-A chain mRNA. By thymidine autoradiography, intimal SMC were observed to be proliferating in the inner third of the intima. These data demonstrate a difference in the pattern of PDGF transcript expression and luminal perfusate activity in graft as compared with control arteries. The association of intimal smooth muscle cell proliferation with intimal PDGF mRNA expression and release of PDGF-like protein supports the hypothesis that factors from cells that have grown into the graft or populated its surface rather than platelets may regulate intimal smooth muscle cell proliferation in this model.

Animals↗
PubMed1990

Healing of polytetrafluoroethylene arterial grafts is influenced by graft porosity.

The importance of porosity in synthetic arterial graft healing has not been adequately defined. To determine the effect of porosity on graft healing, we measured the extent of cellular response at late times in 4 mm internal diameter polytetrafluoroethylene grafts of varying porosity (between 10 and 90 microns internodal distance) inserted into the arterial system of baboons. After 1 and 3 months the grafts were retrieved and examined for endothelial coverage, intimal thickening, and endothelial cell and smooth muscle cell proliferation. The pattern of intimal healing with endothelial cells and smooth muscle cells was only related to porosity in the sense that there was an abrupt switch in the pattern of healing as porosity was increased from 30 to 60 microns. In low porosity grafts (10 and 30 microns internodal distances) endothelial coverage of the luminal surface was incomplete and, along with intimal thickening, was limited to graft near the anastomosis. In high porosity grafts (60 and 90 microns internodal distances) luminal endothelial coverage was complete, and intimal thickening was uniformly distributed throughout the graft. The highest porosity graft studied (90 microns) developed areas of focal loss of endothelial cells at late time periods. In this limited series there does appear to be an optimal porosity for polytetrafluoroethylene grafts near 60 microns, since 10 and 30 micron grafts fail to achieve luminal endothelial cell coverage, and 90 micron grafts exhibit instability of the intima with focal endothelial cell loss.

Animals↗
PubMed1990

Selective evaluation and management of coronary artery disease in patients undergoing repair of abdominal aortic aneurysms. A 16-year experience.

Reduction of cardiac mortality associated with abdominal aortic aneurysm (AAA) repair remains an important goal. Five hundred consecutive urgent or elective operations for infrarenal nonruptured AAA were reviewed. Patients were divided into three groups based on preoperative cardiac status: group I (n = 260, 52%), no clinical or electrocardiographic (ECG) evidence of coronary artery disease (CAD); group II (n = 212, 42.2%), clinical or ECG evidence of CAD considered stable after further evaluation with studies such as dipyridamole-thallium scanning, echocardiography, or coronary arteriography; group III (n = 28, 5.6%), clinical or ECG evidence of CAD considered unstable after further evaluation. Group I had no further cardiac evaluation and groups I and II underwent AAA repair without invasive treatment of CAD. Group III underwent repair of cardiac disease before (n = 21) or coincident with (n = 7) AAA repair. In all instances, perioperative fluid volume management was based on left ventricular performance curves constructed before operation. The 30-day operative mortality rate for AAA repair in all 500 patients was 1.6% (n = 8). There was one (0.4%) cardiac-related operative death in group I, which was significantly less than the five (2.4%) in group II (p less than 0.02). Total mortality for the two groups were also significantly different, with one group I death (0.4%) and seven group II deaths (3.3%), (p less than 0.02). These data support the conclusions that (1) the leading cause of perioperative mortality in AAA repair is myocardial infarction, (2) correction of severe or unstable CAD before or coincident with AAA repair is effective in preventing operative mortality, (3) patients with known CAD should be investigated more thoroughly to identify those likely to develop perioperative myocardial ischemia so that their CAD can be corrected before AAA repair, and (4) patients with no clinical or ECG evidence of CAD rarely die of perioperative myocardial infarction, and thus selective evaluation of CAD based on clinical grounds in AAA patients is justified.

Aorta, Abdominal↗
PubMed1990

Growth factor gene expression by intimal cells in healing polytetrafluoroethylene grafts.

Vascular smooth muscle cell proliferation resulting in intimal hyperplasia is a major cause of late graft failure. In baboons, healing 60 microns internodal distance polytetrafluoroethylene vascular grafts form an intima composed of proliferating smooth muscle cells with a luminal lining of endothelium. The presence of intimal smooth muscle cell proliferation underneath an intact endothelium, without platelet adherence, suggests that intimal cells rather than platelets may provide the growth factors regulating the smooth muscle cell proliferation. This idea is supported by the observation that, when segments of graft and artery are excised and perfused ex vivo, there is greater mitogenic activity present in the graft perfusate compared to artery perfusate. Two factors expressed by vascular wall cells and known to influence smooth muscle cell growth in vitro are platelet-derived growth factor and transforming growth factor-beta 1. The expression of these growth factors was measured by Northern blot analysis of total ribonucleic acid extracted from thoracic aorta and the intima of 6-week thoracoabdominal polytetrafluoroethylene grafts, and from smooth muscle cell cultured from the aorta and polytetrafluoroethylene graft. Growth of the cultured smooth muscle cell was arrested in serum-free conditions for 3 days and then stimulated with 10% fetal calf serum. Twenty-four hours later, the smooth muscle cells were harvested. Probing the blots for platelet-derived growth factor-A, platelet-derived growth factor-B, and transforming growth factor-beta 1 messenger ribonucleic acid revealed that in vivo, the graft intima expressed more platelet-derived growth factor-A than the aorta.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Correlative aspects of hypervolemic hemodilution: low-molecular-weight dextran infusions after experimental cerebral arterial occlusion.

Unilateral clipping of cerebral arteries in eight dogs reduced regional cortical blood flow (rCoBF) without altering cardiac output (CO) or intracranial pressure (ICP) and resulted in 10% hemispheric infarction. In ten dogs, total blood volume (TBV), CO, rCoBF in the region of the occluded artery, and ICP increased while the hematocrit (Hct) decreased following two low-molecular-weight dextran (D40) infusions. Hemispheric infarction was 4%. The CO, rCoBF, and ICP correlated directly with TBV, but inversely with Hct, while rCoBF correlated positively with CO. Two similar hemodiluting D40 infusions in nine control dogs raised TBV, CO, and ICP but not rCoBF. The CO, rCoBF, and ICP correlated positively with TBV but inversely with Hct while rCoBF correlated with CO. Thus, hypervolemic hemodilution with D40 enhances collateral perfusion to acutely ischemic regions of brain distal to segmental arterial occlusions and concomitantly augments CO and ICP. Correlations between CO and cerebral blood flow after D40 infusion may be secondary to lowered Hct.

Animals↗
PubMed1983

Hypervolemic hemodilution in experimental focal cerebral ischemia. Elevation of cardiac output, regional cortical blood flow, and ICP after intravascular volume expansion with low molecular weight dextran.

Cerebrovascular and cardiac alterations evoked by intravascular volume expansion with low molecular weight dextran (LMD, molecular weight 40,000), an advocated adjunct in the clinical prevention or therapy of acute stroke and cerebral vasospasm, were studied in splenectomized dogs. Clipping of the right distal internal carotid artery and the proximal middle cerebral artery (MCA) in eight dogs decreased regional cortical blood flow (rCoBF) by 58% without changing cardiac output (CO), and caused 10% +/- 5% (SE) hemispheric infarction. Ten other dogs underwent similar cerebral arterial occlusion and were infused twice with LMD within 2 hours; each infusion equaled 20% of the respective dog's total blood volume. Both CO and rCoBF in the territory of the occluded MCA increased significantly by 119% +/- 13% and 42% +/- 6%, respectively. following the two LMD infusions. Although the mean arterial blood pressure was unaltered, the hematocrit decreased significantly and the intracranial pressure (ICP) increased significantly. The mean hemispheric infarction in these 10 treated dogs was 4% +/- 2%. Another nine dogs underwent arterial manipulation without clipping. Two hemodiluting LMD infusions, similar to those in the 10 dogs, significantly elevated CO and ICP but not rCoBF. These data suggest that hypervolemic hemodilution with LMD effectively elevates collateral perfusion to ischemic regions of brain distal to occluded MCA segments and concomitantly raises the CO and ICP.

Animals↗
PubMed1981

Differences of adrenal stress control mechanisms in subjects with glaucoma and normal subjects. Effect of vasopressin and pyrogen.

Various types of glaucomatous and normal subjects were tested for the adequacy of the stress response of their hypothalamic-pituitary-adrenal axis to pyrogen and vasopressin. With pyrogen, a significant response of elevation of plasma cortisol levels was positively correlated with ocular pressure and changes of the optic disc. Those subjects with increased ocular pressure and optic disc cupping and pallor had greater rises of plasma cortisol levels. With vasopressin, a decreased response of plasma cortisol levels was negatively correlated with the degree of elevated ocular pressure. Those subjects with increased ocular pressure and lower tonographic outflow facilities had smaller rises of plasma cortisol levels. Both tests indicated a disturbance of the hypothalamic-pituitary-adrenal axis in subjects with glaucoma.

Female↗
PubMed1976

You known who and what's her name: the woman's role in sex therapy.

As sex therapy becomes an established mode of treatment, the original Masters and Johnson model of cotherapy is its most common form. The complex issues in the relationship between cotherapists who are doing sex therapy have not received adequate attention. Differences in status, experience, and training combine with aspects of the personal relationship between therapists to make cotherapy a substantial problem. Whether the cotherapists are married, otherwise involved in a personal relationship, or even when they are a physician and his nurse or two independent therapists, the sexual content of their work inevitably raises issues that need to be resolved. These issues include erotic fantsies and power struggles between the therapists that can affect the outcome of treatment.

Counseling↗
PubMedDate not supplied

Gadolinium-enhanced ultrafast three-dimensional spoiled gradient-echo MR imaging of the abdominal aorta and visceral and iliac vessels.

Gadolinium-enhanced ultrafast three-dimensional (3D) spoiled gradient-echo magnetic resonance (MR) imaging is a noninvasive method for evaluating the abdominal aorta and the visceral and iliac vessels. With an enhanced gradient system, 20-48 sections can be obtained during a single 18-32-second patient breath hold. The 3D volume obtained from a single acquisition can be reformatted at a workstation and the vascular anatomy viewed in any projection and with a variety of section thicknesses, making this MR imaging technique particularly useful in the evaluation of aberrant arteries, vascular stenoses, aneurysms, and dissection flaps. Gadolinium-enhanced ultrafast 3D spoiled gradient-echo MR imaging has been used instead of or in addition to conventional contrast material-enhanced MR angiography in patients who have chronic symptoms of mesenteric ischemia, who have abdominal aortic aneurysms, or who are at risk for iodinated contrast material-related renal dysfunction. This technique shows great promise for accurate and noninvasive evaluation of the abdominal aorta and the visceral and iliac vessels.

Adult↗