Cancer gene therapy using a survivin mutant adenovirus.

We have constructed a replication-deficient adenovirus encoding a nonphosphorylatable Thr(34)-->Ala mutant of the apoptosis inhibitor survivin (pAd-T34A) to target tumor cell viability in vitro and in vivo. Infection with pAd-T34A caused spontaneous apoptosis in cell lines of breast, cervical, prostate, lung, and colorectal cancer. In contrast, pAd-T34A did not affect cell viability of proliferating normal human cells, including fibroblasts, endothelium, or smooth muscle cells. Infection of tumor cells with pAd-T34A resulted in cytochrome c release from mitochondria, cleavage of approximately 46-kDa upstream caspase-9, processing of caspase-3 to the active subunits of approximately 17 and 19 kDa, and increased caspase-3 catalytic activity. When compared with chemotherapeutic regimens, pAd-T34A was as effective as taxol and considerably more effective than adriamycin in induction of tumor cell apoptosis and enhanced taxol-induced cell death. In three xenograft breast cancer models in immunodeficient mice, pAd-T34A suppressed de novo tumor formation, inhibited by approximately 40% the growth of established tumors, and reduced intraperitoneal tumor dissemination. Tumors injected with pAd-T34A exhibited loss of proliferating cells and massive apoptosis by in situ internucleosomal DNA fragmentation. These data suggest that adenoviral targeting of the survivin pathway may provide a novel approach for selective cancer gene therapy.

Human T cells infiltrate and injure pig coronary artery grafts with activated but not quiescent endothelium in immunodeficient mouse hosts.

BACKGROUND: We have previously demonstrated that human artery grafts transplanted to immunodeficient mice are infiltrated and injured by unsensitized allogeneic human T cells. We extended our investigations to human anti-porcine xenoresponses in this model. METHODS: Pig coronary artery segments were interposed into the infrarenal aorta of severe combined immunodeficiency/beige mice. After 7 days, certain recipients were reconstituted with human leukocytes and/or treated with proinflammatory cytokines. The grafts were harvested after 1-70 days and examined by histology, immunohistochemistry, and morphometry. RESULTS: Pig artery grafts from untreated mice had no evidence of injury, leukocytic infiltrate, or endothelial cell activation up to 70 days postoperatively, despite deposition of murine complement. Host reconstitution with human peripheral blood mononuclear cells resulted in a discrete population of circulating T cells that did not infiltrate or injure the grafts up to 28 days after adoptive transfer. Administration of porcine interferon-gamma for up to 28 days sustained the expression of graft vascular cell adhesion molecule-1 and major histocompatibility complex antigens, but did not initiate recruitment of human leukocytes. In contrast, treatment with human tumor necrosis factor for 7 days induced the de novo expression of porcine E-selectin by graft endothelial cells and elicited human T cell infiltration and human peripheral blood mononuclear cell-dependent vascular injury. CONCLUSIONS: The human peripheral blood mononuclear cell-severe combined immunodeficiency/beige mouse model identifies a significant difference between human T cell allogeneic and xenogeneic responses in vivo. Xenografts with quiescent endothelium are not infiltrated or injured by T cells under the same conditions in which allografts are rejected. Activation of pig coronary artery endothelial cells by human tumor necrosis factor, but not porcine interferon-gamma, elicits cellular xenoresponses.

Single-clamp technique does not protect against cerebrovascular accident in coronary artery bypass grafting.

OBJECTIVES: By potentially avoiding the embolic consequences of a side-biting aortic clamp, the single-clamp technique may decrease cerebrovascular accidents in coronary artery bypass grafting. However, this theoretical superiority in stroke prevention has not been conclusively demonstrated and use of this technique may lead to adverse myocardial effects due to longer cross-clamp times. In this study, we sought to determine if the single-clamp technique prevents postoperative stroke in clinical practice. METHODS: Of 607 consecutive isolated coronary bypass operations completed over a 3 year period, 301 (50%) were performed by one surgeon using exclusively the single-clamp technique and 306 (50%) were performed by a second surgeon using exclusively the two-clamp technique. Postoperative adverse events were retrospectively compared between these two groups. RESULTS: There were no differences between groups in terms of postoperative stroke (1.7% single-clamp vs. 2.0% two-clamp, P=0.78), hospital mortality (2.7% single-clamp vs. 1.6% two-clamp, P=0.38), or perioperative myocardial infarction (2.6% single-clamp vs. 0.7% two-clamp, P=0.052). The two-clamp technique was not a significant predictor of stroke by logistic regression analysis (P=0.72). CONCLUSIONS: We conclude that there are no statistically significant differences between clamp techniques with regard to stroke prevention or myocardial protection. We find no compelling evidence for surgeons successfully utilizing one technique to change to the other.

Effect of left ventricular volume on results of coronary artery bypass grafting.

After coronary artery bypass grafting, our patients with ischemic cardiomyopathy and significant left ventricular (LV) dilation demonstrated an improvement in angina symptoms, acceptable operative and medium-term survival, a trend toward improvement in LV ejection fraction, and a significant reduction in LV chamber size. Our results suggest that patients with ischemic cardiomyopathy and LV dilation should not be excluded from surgical revascularization based on ventricular size alone.

Human TNF can induce nonspecific inflammatory and human immune-mediated microvascular injury of pig skin xenografts in immunodeficient mouse hosts.

TNF activates endothelial cells to express cell surface molecules that are necessary to recruit a local infiltrate of leukocytes. Because the actions of this proinflammatory cytokine are not species restricted, we investigated whether human TNF can up-regulate porcine endothelial adhesion molecules to elicit human T cell infiltration and damage of pig skin xenografts in a chimeric immunodeficient mouse model. We have previously demonstrated the vigorous rejection of human skin allografts and the absence of injury to porcine skin xenografts in human PBMC-SCID/beige mice. Intradermal administration of human TNF at high doses (600 or 2000 ng) caused nonspecific inflammatory damage of pig skin grafts, whereas low concentrations of TNF (60 or 200 ng) resulted in human PBMC-dependent injury of porcine endothelial cells. There was a strong correlation among pig skin xenograft damage, human T cell infiltration, and the TNF-induced up-regulation of swine MHC class I and class II molecules, VCAM-1, and, in particular, the de novo expression of porcine E-selectin. The microvascular damage and leukocytic infiltration elicited by TNF were enhanced by porcine IFN-gamma, suggesting that xenografts may be less prone to cytokine-mediated injury due to the species-restricted effects of recipient IFN-gamma. Our results indicate that maintenance of a quiescent endothelium, which does not express E-selectin or other activation-dependent adhesion molecules, is important in preventing human anti-porcine T cell xenoresponses in vivo and that TNF signaling molecules and TNF-responsive gene products are appropriate therapeutic targets to protect against human T cell-mediated rejection of pig xenografts.

Interferon-gamma elicits arteriosclerosis in the absence of leukocytes.

Atherosclerosis and post-transplant graft arteriosclerosis are both characterized by expansion of the arterial intima as a result of the infiltration of mononuclear leukocytes, the proliferation of vascular smooth muscle cells (VSMCs) and the accumulation of extracellular matrix. They are also associated with the presence of the immunomodulatory cytokine interferon-gamma (IFN-gamma). Moreover, in mouse models of atheroma formation or allogeneic transplantation, the serological neutralization or genetic absence of IFN-gamma markedly reduces the extent of intimal expansion. However, other studies have found that exogenous IFN-gamma inhibits cultured VSMC proliferation and matrix synthesis, and reduces intimal expansion in response to mechanical injury. This discrepancy is generally explained by the idea that IFN-gamma either directly activates macrophages, or, by increasing antigen presentation, indirectly activates T cells within the lesions of atherosclerosis and graft arteriosclerosis. These activated leukocytes are thought to express the VSMC-activating cytokines and cell-surface molecules that cause the observed arteriosclerotic responses. Here we have inserted pig and human arteries into the aorta of immunodeficient mice, and we show that IFN-gamma can induce arteriosclerotic changes in the absence of detectable immunocytes by acting on VSMCs to potentiate growth-factor-induced mitogenesis.

The impact of liposuction on body fat.

Routine liposuction has very low perioperative complication rates and is thus considered to be innocuous. Some authors have even proposed that large-volume liposuction could be therapeutic. However, because subcutaneous adipose tissue has nutritional and thermodynamic metabolic functions proportional to the absolute amount and the distribution of fat, it is possible that removal of subcutaneous adipose tissue might be detrimental. We measured the amount of fat removed by large-volume (>1000 cc) liposuction and expressed the results in terms of absolute and relative changes in total body fat and in visceral adipose tissue (nonsubcutaneous adipose tissue) in 63 normal weight to mildly obese women (n = 51) and men (n = 12). Aspiration of 1.5 +/- 0.7 kg (mean +/- SD) of lipid in women removed 9.2 +/- 3.2 percent of body fat or 10.5 percent of subcutaneous adipose tissue corresponding to a 12-percent increase in the ratio of visceral to subcutaneous adipose tissue. One third of the women (n = 17) had a mean increase of 16 percent (range 13 to 21 percent) in the proportion of visceral fat. In the 12 men, aspiration of 1.7 +/- 0.6 kg of lipid removed 9.8 +/- 2.9 percent of body fat or 12.7 +/- 3.6 percent of subcutaneous adipose tissue, resulting in a 14-percent increase in the ratio of visceral to subcutaneous fat. The correlation between aspirate and body mass index was 0.57 (p < 0.001). Although large-volume subcutaneous liposuction removed relatively little body fat, it led to significant increases in the proportion of visceral adipose tissue. Because the proportion of visceral adipose tissue is a risk factor for metabolic complications of obesity, the metabolic effects of large-volume liposuction need to be evaluated.

Pathogenesis of systemic air embolism during bronchoscopic Nd:YAG laser operations.

BACKGROUND: The occurrence of systemic air embolism during bronchoscopic neodymium:yttrium-aluminum garnet laser operations has been suspected. Here we describe its mechanism. METHODS: Two patients with embolic cardiac and neurologic complications after bronchoscopic neodymium: yttrium-aluminum garnet laser tumor ablation are described. A subsequent third patient was monitored for intracardiac and aortic air by transesophageal echocardiography. A review of the literature and safety recommendations are discussed. RESULTS: The appearance of systemic air emboli was related to the use of the laser fiber air coolant at high flow and resolved by decreasing the air flow. The presence of intracardiac and aortic air was associated with hypotension and inferior ischemic electrocardiographic changes. CONCLUSIONS: Systemic air embolism during bronchoscopic laser operations is a potentially catastrophic complication and is related to the use of gas-cooled laser fibers and contact probes. We recommend using the noncontact mode whenever possible and maintaining the coaxial coolant air flow at the minimum level or using a fluid coolant if contact is necessary.

Staining intensity of brain iron in patients with schizophrenia: a postmortem study.

Evidence derived from both pharmacological and postmortem studies suggests that a disturbance of brain iron metabolism is involved in the pathophysiology of schizophrenia; i.e., the distribution of iron parallels that of dopamine, and variations in its brain concentration selectively modulate the binding affinity of the dopaminergic (D2) receptor. In the present study the authors examined the staining intensity of brain iron in postmortem specimens of 9 schizophrenic (SC) patients and 17 age-matched controls. Coronal sections were stained with the Perls's technique, photographed, and then studied using a computerized image analysis system. Optical density measurements were taken from the caudate nucleus, putamen, globus pallidus, and substantia nigra. This study revealed significant differences between groups only for the staining intensity of iron in the caudate nucleus (P less than 0.005). A review of the literature suggests that this finding may be the result of neuroleptic therapy and not a primary pathological feature of schizophrenia.

Accuracy of dual-energy radiographic absorptiometry of the lumbar spine: cadaver study.

Dual-energy radiographic absorptiometry (DRA) was used to measure the bone mineral content and area density of lumbar vertebrae (L2-L3) in 11 cadavers. These data were subsequently compared with measured ash content and density. Excellent correlation was obtained between bone mineral content measured with DRA and ash weight (r = .963, P less than .0001). The accuracy error in determining mineral content in lumbar vertebrae with DRA was about 9%. In addition, strong correlation was observed between bone mineral density measured with DRA and ash density (r = .881, P less than .0001).