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Biomedical subjects

A M Graham

Publications and source records attributed to A M Graham.

At least 19 recordsLinked to original sources
PubMed2001

Heterotypic smooth muscle cell/endothelial cell interactions differ between species.

BACKGROUND: In vitro coculture models have been used to study heterotypic cell-cell interactions. This study was performed to determine if species of cell origin affects heterotypic smooth muscle cell (SMC) endothelial cell (EC) interactions in coculture. METHODS: To study the effect of ECs on SMC proliferation, ECs were cultured on porous Dacron membranes. SMCs were added opposite the ECs or on bare membranes on Day 3, and after 4 days, cells were harvested for cell counts. To study the effect of SMCs on EC proliferation, ECs at a density of 5 x 10(5) cells/membrane were added to bare membranes or on membranes opposite SMCs plated 2 days earlier. After 48 h, cells were harvested for cell counts. (N = 3/condition, experiments repeated x2.) Cells of human and bovine aortic origin were used. RESULTS: The effect of coculture on cell growth differed between species. The effect of heterotypic interactions between human cocultured cells was coinhibitory on the rate of growth as compared to the growth of cells cultured alone. Growth of cocultured ECs was 55.2 +/- 8.7% less than that of ECs cultured alone while growth of cocultured SMCs was 27.2 +/- 6.0% less than growth of SMCs cultured alone. This contrasted with the bovine EC stimulation of SMC proliferation, with 66.8 +/- 5.0% greater growth of cocultured SMCs compared to SMCs cultured alone, and failure of bovine SMCs to decrease EC proliferation. CONCLUSIONS: Since significant differences in cell-material interactions occur in vivo between species, the finding that in vitro heterotypic cell-cell interactions are species dependent is not surprising. This fundamental difference in cell behavior stresses the potential importance of using human cells in studies evaluating cell-cell and cell-material interactions in vitro.

Animals↗
PubMed2001

Predictors of health after operation for aortoiliac occlusive and aneurysmal disease.

BACKGROUND: We assessed the impact of comorbid conditions and revascularization for aortoiliac occlusive and aneurysmal disease and determined the functional health status of patients with the Medical Outcomes Study SF36 Health Survey. METHODS: One hundred twenty-five patients were surveyed prospectively, before operation, and at intervals ranging from 2 weeks to 2 years after operation. To identify the factors that influenced functional health, multiple regression analysis was performed to test the hypothesis that age, pulmonary disease, atherosclerotic heart disease, diabetes, aortoiliac occlusive disease (AOD) versus aneurysmal disease, and the preoperative physical summary score affected outcome. RESULTS: Regression analysis identified that before operation, the physical summary score (PCS) was affected by pulmonary disease, atherosclerotic heart disease, and AOD, and patients with AOD had significantly worse PCS than patients with aneurysmal disease (43.2 +/- 12.6 vs 30.1 +/- 8.3, P <.05). This difference was also present after 3 to 12 months, and the preoperative PCS was the strongest predictor of the postoperative score. For patients followed up between 1 and 2 years, there was no significant difference among the groups, and atherosclerotic heart disease and pulmonary disease were identified to most affect the PCS. CONCLUSIONS: Patients with AOD have significantly impaired physical function (as compared with patients with aneurysmal disease) that is successfully reversed with a surgical procedure. The functional health of patients after operation for aneurysmal disease returns to baseline after 3 and 12 months. Ultimately, cardiac and pulmonary comorbidities have a continued effect on the functional health of patients.

Activities of Daily Living↗
PubMed2001

Human monoclonal anti-endothelial cell IgG-derived from a systemic lupus erythematosus patient binds and activates human endothelium in vitro.

Our objectives were to obtain monoclonal anti-endothelial cell antibodies (AECA) from systemic lupus erythematosus (SLE) patients, to characterize their antigen specificity, and their capability to induce a pro-inflammatory and pro-adhesive endothelial phenotype, and to investigate the mechanism of endothelial cell (EC) activation in vitro. Monoclonal IgG AECA were generated by hybridoma formation with human SLE B cells. Antigen specificity was characterized by immunoblotting with enriched cell membrane fractions, by cytofluorimetry and by cell solid-phase ELISA. Endothelial activation was evaluated by measuring increases in U937 cell adhesiveness, adhesion molecule (E-selectin and ICAM-1) expression and IL-6 production. In addition, mechanisms of endothelial activation were investigated by assessment of NF-kappaB by measuring the loss of its inhibitor I-kappaB. mAb E-3 bound live EC and recognized a 42 kDa EC membrane protein, it enhanced U937 adhesiveness, E-selectin and ICAM-1 expression and IL-6 production, and caused the loss of I-kappaB. We conclude this is the first in vitro demonstration that a human monoclonal AECA from a SLE patient reacts with a constitutive endothelial membrane antigen and induces a pro-inflammatory endothelial phenotype through NF-kappaB activation.

Antibodies, Monoclonal↗
PubMed2000

alpha-melanocyte-stimulating hormone modulates nitric oxide production in melanocytes.

We have previously observed that melanocytes produce nitric oxide in response to ultraviolet radiation and lipopolysaccharide and in this study have examined how these responses are affected by alpha-melanocyte-stimulating hormone. Nitric oxide production by cultured cells was measured electrochemically in real time using an ISO-nitric oxide sensor probe. B16 mouse melanoma cells released nitric oxide in response to lipopolysaccharide and the effects were enhanced in cells that had been grown in the presence of 10-11-10-9 M alpha-melanocyte-stimulating hormone prior to stimulation. At concentrations in excess of 10-9 M alpha-melanocyte-stimulating hormone decreased nitric oxide production. Preincubation with lipopolysaccharide, a well-known inducer of inducible nitric oxide synthase, also increased nitric oxide production but this response was reduced by alpha-melanocyte-stimulating hormone. alpha-Melanocyte-stimulating hormone also increased the levels of nitric oxide produced in response to ultraviolet radiation (20-100 mJ per cm2) in B16 cells. The same effect was seen in human melanocytes and as this was inhibited by aminoguanidine would appear to involve an induction of inducible nitric oxide synthase. Reverse transcription-polymerase chain reaction showed that melanocytic cells express inducible nitric oxide synthase mRNA. Western blotting analysis and immunocytochemistry confirmed the presence of inducible nitric oxide synthase protein in B16 cells and FM55 human melanoma cells and that the levels were increased in response to alpha-melanocyte-stimulating hormone. alpha-Melanocyte-stimulating hormone, however, decreased inducible nitric oxide synthase protein expression, which occurred in response to lipopolysaccharide. These results suggest that alpha-melanocyte-stimulating hormone regulates nitric oxide production in melanocytic cells by modulating the induction of inducible nitric oxide synthase. Additional experiments showed that nitric oxide increased melanin production by B16 cells and human melanocytes. This is in keeping with a melanogenic role for nitric oxide but whether its production by melanocytes in response to alpha-melanocyte-stimulating hormone is associated with such a role or whether it has some other significance relating to melanocyte differentiation or in mediating immunomodulatory actions of alpha-melanocyte-stimulating hormone remains to be seen.

Adolescent↗
PubMed2000

Predictors of health after revascularization for extremity ischemia.

BACKGROUND: To assess the impact of surgical revascularization for lower extremity ischemia, we determined (with the use of the SF-36 health survey) the functional health status of patients who underwent either inflow or outflow procedures. METHODS: The SF-36 survey was given prospectively to 104 patients before operation and at intervals ranging from 10 days to 1 year after operation from January 1998 to July 1999. To determine whether revascularization was associated with improved patient health status, mean scores were compared before and after operation by univariate and multivariate analysis. To identify the factors that influenced patient health status, we performed multiple regression analysis to test the hypothesis that outcome is affected by age, gender, time since procedure, diabetes, indication, and inflow versus outflow procedure. RESULTS: There was a significant decrease in the general health score of patients before outflow bypass as compared with inflow procedure (45.3 +/- 5.3 versus 32.1 +/- 3.3 [mean +/- SEM]; P <.05). After the procedure, only those patients who had undergone inflow procedures had improved outcome scores. Diabetes, outflow procedures, limb salvage as indication, and time since operation were determined by multiple regression affecting outcome scores to be significant factors. CONCLUSIONS: The SF-36 health survey demonstrated that diabetes, procedure type, indication, and time after procedure significantly affected the functional outcome for patients who were treated surgically for lower extremity ischemia. Despite successful revascularization, significant deficits in functional health remain in patients with lower extremity ischemia.

Aged↗
PubMed1999

Endovascular management of ureteroarterial fistula.

Ureteroarterial fistulas, although rare, appear to be increasing in frequency. Because open surgical repair may be difficult and associated with significant risk for complications, endovascular intervention may provide an attractive treatment alternative. We review the diagnosis and management of a ureteroarterial fistula and iliac pseudoaneurysm that presented with massive hematuria during ureteral stent removal. The patient was treated by means of the percutaneous embolization of the right hypogastric artery and placement of an expanded polytetrafluoroethylene stent-graft. Endovascular stent-graft placement may serve as a safe and practical alternative in the treatment of these patients, whose cases are challenging.

Angiography, Digital Subtraction↗
PubMed1998

Intrahepatic proliferation of 'naive' and 'memory' T cells during liver allograft rejection: primary immune response within the allograft.

Liver allograft rejection is mediated by a primary response of T lymphocytes, followed by infiltration of the graft with a mixed inflammatory reaction. Using single and double label immunocytochemistry, we examined the proliferation index and the phenotype of leukocytes on liver biopsies from 10 patients with acute rejection before and after treatment with i.v. steroids, 10 patients with chronic rejection, 10 patients without rejection posttransplant, and 15 nongrafted, nonimmunosuppressed patients. Proliferation of mononuclear leukocytes (assessed by expression of Ki-67, a nuclear antigen associated with the cell cycle) inside the allograft was a prominent feature of acute and chronic rejection and was down-regulated by steroid treatment. Leukocytes in cell cycle were located predominantly in the portal tracts at the site of the inflammatory infiltrate. The majority of 'naive' (CD45RA+) and 'memory' (CD45RO+) CD4+ T lymphocytes were also periportally distributed. In contrast, CD8+ T lymphocytes, CD57+ natural killer cells, and CD68+ macrophages were located intraparenchymally throughout the liver lobules, whereas CD20+ B lymphocytes were only present in some of the portal tracts. Predominantly CD4+ and occasionally CD8+ lymphocytes were proliferating (assessed by double staining). The proliferating CD4+ cells were of both naive (CD4+, CD45RA+) and memory (CD4+, CD45RO+) phenotypes. To our knowledge, this is the first description of proliferating naive T lymphocytes in situ in liver allografts. These findings suggest that there may be a primary immune response generated within the allograft as well as in draining lymphatic tissue. This implicates not only intrahepatic proliferation of T lymphocytes as a prominent feature of rejection, but also suggests that the liver has a special immunological status comparable to that of lymphatic tissue.

Adult↗
PubMed1998

Bile duct cells in primary biliary cirrhosis are 'primed' for apoptosis.

OBJECTIVE: Primary biliary cirrhosis (PBC) is characterized by progressive, immune-mediated destruction of bile ducts (<75 microm diameter) and secondary changes related to cholestasis which may involve apoptosis. In this study we sought to examine the protein expression of genes involved in apoptosis in biliary epithelium of PBC cases. DESIGN: In order to investigate the susceptibility of biliary epithelial cells to apoptosis and their ability to proliferate, we examined the expression of a number of apoptosis related proteins in early and late stage PBC and histologically normal liver control tissue using immunohistochemistry. METHODS: Liver biopsies from 15 early (stages I and II) and 14 late (stages III and IV) cases of PBC and 15 normal cases were examined immunohistochemically for expression of p53, CD95/Fas, bax, bcl-x, bcl-2 and the proliferation marker Ki-67. RESULTS: CD95/Fas, bax and bcl-x were identified in biliary epithelium in 8/15, 11/15 and 8/15 normal biopsies. Weak expression of bcl-2 was found, but p53 was not identified. In cases of PBC surviving bile ducts showed strong bax and bcl-x expression. Inflammatory infiltrates were strongly bcl-2 positive. In cases showing a marked ductular reaction there was increased reactivity for bax and bcl-x in ductules. No change in CD95/Fas or p53 expression was seen. An increase in Ki-67 positive biliary epithelial cells was seen in PBC cases, indicating cell cycle activity. CONCLUSIONS: Bile duct epithelium constitutively expresses several genes involved in the execution of apoptosis but these cells also retain the ability to proliferate.

Apoptosis↗
PubMed1998

Development of wall surface tangent DPIV measurement techniques for arterial branch models.

Experimental techniques for measuring unsteady flow in a glass arterial bifurcation model have been developed to aid in quantifying three-dimensional wall shear fluctuations associated with arterial disease. The unique feature of the current technique is the use of a "curved" laser sheet, which was everywhere tangent to the inner wall of a daughter tube in an arterial bifurcation model. Surface tangent velocity vector field measurements were made to demonstrate the potential of this technique. Ensemble-averaged data showing weak secondary flows as well as statistical distributions of flow angles are presented. Measurements of this type may be used to estimate mean and instantaneous wall shear magnitude and direction, data that are necessary for understanding the importance of circumferential motions on arterial disease.

Arterioles↗
PubMed1998

Elective aortic surgery with minimal banked blood.

It has been a historical supposition that aortic surgery, even in an elective setting, has been associated with the transfusion of large amounts of blood products. We feel that this assumption is now dated, and in fact far fewer patients now receive allogenic blood products. To assess this assumption, we carried out a retrospective chart review of all patients who underwent elective aortic surgery over an 18-month period from April 1994 to October 1995. Factors analyzed included type of procedure, blood loss, amount of Cell Saver blood replaced, need for autologous blood transfusion, and need for allogenic blood transfusion. Sixty-seven patients underwent elective aortic surgery with either an aortic tube graft (23), an aortobiiliac graft (25), or an aortobifemoral graft (19). The male:female ratio was 48:19, with a mean age of 67 years (range, 42-85 years). Mortality and morbidity were 4.4 per cent and 8.9 per cent, respectively. The average blood loss per patient was 770 cc. Cell saver was used in 65 patients, with the average amount of blood returned being 542 cc. Overall, 73 per cent of patients did not require allogenic blood transfusion, and 58 per cent did not need any type of transfusion. Of those who stored autologous blood prior to operation, none required allogenic blood perioperatively. With the new advances in autologous blood transfusion both by predeposit and salvage transfusion, we have greatly reduced the need for transfusion of allogenic blood products in patients undergoing major aortic surgery. This is reassuring, and although increasing short-term cost, will reduce the morbidity-infectious, noninfectious, and immunologic-associated in prior decades with allogenic blood transfusions. We strongly recommend the use of Cell Saver techniques, and also, where possible, patients should be encouraged to donate their own blood prior to major aortic procedures for future transfusion.

Adult↗
PubMed1998

Flow modulates endothelial regulation of smooth muscle cell proliferation: a new model.

BACKGROUND: With a co-culture model, we have previously demonstrated that endothelial cells (ECs) exert regulatory control over smooth muscle cell (SMC) behavior. ECs appeared to stimulate SMC proliferation in static culture. This study was performed to test the hypothesis that the EC stimulation of SMC proliferation was effected by shear stress. METHODS: Bovine SMCs were cultured on a thin semipermeable membrane either alone or opposite ECs in co-culture (SMC/EC). A novel parallel-plate flow device was developed and used for exposing the EC side of the co-culture to shear stress. EC and SMC proliferation rates were determined after 24 hours' exposure to 0, 1, or 10 dynes/cm2 of shear stress. RESULTS: SMC proliferation decreased significantly from 362 +/- 65 cpm/microgram DNA (control, mean +/- SEM) to 68 +/- 43 cpm/microgram (1 dyne/cm2) and 99 +/- 18 cpm/microgram (10 dynes/cm2)(P < .05). EC proliferation after flow decreased as compared with no-flow controls 71 +/- 15 cpm/micrograms DNA (control, mean +/- SEM) to 29 +/- 5 cpm/microgram (1 dyne/cm2) and 21 +/- 4 cpm/microgram (10 dynes/cm2)(P < .05). CONCLUSIONS: In a model designed to study SMC/EC interactions in a flow environment, it was seen that EC exposure to shear stress alters the growth characteristics of SMCs. This suggests that hemodynamic mechanical forces may be sufficient to alter the EC regulation of SMC behavior.

Animals↗
PubMed1997

Efficacy of prophylactic vena cava filters in high-risk trauma patients.

Severely injured trauma patients are at increased risk of pulmonary embolism (PE). Certain injuries may preclude the use of standard prophylactic measures, and even when used, these measures may be ineffective in the trauma population. We defined a group of trauma patients who are at statistically elevated risk of venous thromboembolic events. We then adopted an aggressive approach to the placement of prophylactic inferior vena cava (IVC) filters in these high-risk patients. Between January 1994 and January 1996 we treated 250 trauma patients who met our high-risk criteria. Prophylactic IVC filters were placed in 99 of these patients, and 151 received deep venous thrombosis prophylaxis with either heparin, sequential compression stockings, or a combination of these modalities. High-risk patients did not receive filters if they were unlikely to survive or showed rapid clinical improvement and were felt to not remain at high risk. The incidence of pulmonary embolism in this high-risk population was 1.6%. This is a significant reduction (p = 0.045, Fisher exact test) from the 4.8% incidence of PE in high-risk historical control patients with similar injury profiles. No patient with a prophylactic IVC filter suffered a clinically evident PE and there were no complications associated with placement of these filters. We conclude that the placement of prophylactic IVC filters in high-risk trauma patients is a safe and effective method of reducing the incidence of pulmonary embolism.

Adult↗
PubMed1997

The utility of dobutamine echocardiography in preoperative evaluation for elective aortic surgery.

BACKGROUND: Preoperative cardiac evaluations have been advocated prior to major vascular procedures to reduce the incidence of postoperative cardiac complications. This study was undertaken to evaluate the efficacy and predictive value of routine dobutamine echocardiography (DE) in the screening of patients undergoing elective aortic surgery. METHODS: Dobutamine echocardiography was performed preoperatively on all patients having elective aortic procedures by our university surgical group from June 1995 to August 1996. The cardiac morbidity and mortality from this group were compared with that of a similar group undergoing elective aortic procedures from June 1993 to May 1995 with no dobutamine echocardiography (NDE). RESULTS: Although there was no statistically significant difference in either overall mortality (4.4% in NDE vs. 2.3% in DE) or cardiac mortality (2.9% in NDE vs. 0% in DE) between the two groups, cardiac events occurred only in those patients with previous coronary artery disease. In addition, dobutamine echocardiography had a negative predictive value of 97% CONCLUSIONS: Although routine screening is not necessary, selective screening of patients using dobutamine stress echocardiography is justified because of its high negative predictive value.

Adrenergic beta-Agonists↗
PubMed1995

Symptomatic subclavian steal syndrome four decades after operation for dysphagia lusoria.

Congenital abnormalities of the aortic arch may lead to signs and symptoms of tracheal and esophageal obstruction secondary to a restrictive vascular ring. There are many case reports and monographs concerning the surgical management of dysphagia lusoria. This case provides the first example of long-term follow-up of surgical intervention for relief of dysphagia lusoria. A 45-year-old laborer presented with a several year history of episodic bilateral blindness and a more recent onset of "drop attacks." Notably this patient had presented at the age of 18 months with difficulty breathing and eating since birth. The patient also had frequent upper respiratory infections and episodes of pneumonia. Workup revealed a right-sided aortic arch with a left ligamentum arteriosum. When he was first seen in our clinic, history and physical examination revealed claudication and diminished pulses in the left upper extremity. Arteriography and duplex studies confirmed reversal of flow in the patient's left vertebral artery. The arteriogram demonstrated the presence of a right-sided aortic arch and descending aorta along with the proximal stump of the previously ligated left subclavian artery. He underwent left carotid to left axillary artery bypass for the treatment of symptomatic subclavian steal syndrome. His symptoms have resolved with return of antegrade vertebral flow and the presence of normal pulses in the left arm. Congenital aortic abnormalities that lead to tracheal and esophageal compromise are numerous and varied. Surgical management requires a thorough understanding of the person's anatomy and preoperative planning. The life expectancy of patients with dysphagia lusoria necessitates consideration of the long-term consequences of surgical intervention.

Aorta, Thoracic↗