Intense vasoconstriction in response to aspirate from stented saphenous vein aortocoronary bypass grafts.

OBJECTIVES: We sought to identify soluble vasoconstrictor substances that are released during stent implantation into saphenous vein aortocoronary bypass grafts. BACKGROUND: Atherosclerotic saphenous vein aortocoronary bypass grafts are particularly vulnerable to plaque rupture. Protection devices prevent particulate debris from being embolized. Additional soluble vasoconstrictor substances possibly also contribute to impaired microvascular perfusion. METHODS: Peripheral venous blood (VB) and aspirate (AS) were obtained from 14 patients with a significant stenosis in a saphenous vein graft during stent implantation under protection with a distal balloon occlusion device. In five additional patients, arterial blood (AB) was also taken distal to the stented lesion before intervention. Vasomotor substances in VB, AB, and AS plasma were identified in a bioassay of rat mesenteric arteries with intact (+E) and denuded endothelium (-E). Vasoconstriction was normalized to that induced by potassium chloride depolarization (100%). RESULTS: Venous blood, AB, and AS plasma induced maximum vasoconstriction within six minutes. The AS plasma induced a vasoconstriction of 138 +/- 13% (-E) and 87 +/- 14% (+E); VB, of 70 +/- 14% (-E) and 23 +/- 4% (+E); and AB plasma obtained before intervention, of 49 +/- 9% (-E) and 36 +/- 8% (+E). The vasoconstrictor potency of AS plasma in endothelium-denuded vessels was related to the severity of anginal symptoms, angiographic stenosis severity, plaque volume, and plaque burden as determined by intravascular ultrasound. The AS plasma-induced vasoconstriction was largely attenuated by combined serotonin/5-hydroxytryptamine (5-HT)(2A/2C)- and 5-HT(1A/1B)-receptor blockade and eliminated by additional thromboxane A2 thromboxane-prostanoid (TP)-receptor blockade. CONCLUSIONS: Stent implantation releases, apart from and in addition to particulate debris, soluble vasoconstrictor substances that possibly contribute to impaired microvascular perfusion.     

Cholesterol-sensing receptors, liver X receptor alpha and beta, have novel and distinct roles in osteoclast differentiation and activation.

The liver X receptor (alpha,beta) is responsible for regulating cholesterol homeostasis in cells. However, our studies using the LXRalpha-/-, LXRbeta-/-, and LXRalpha-/-beta-/- mice show that both LXRalpha and beta are also important for bone turnover, mainly by regulating osteoclast differentiation/activity. Introduction: The liver X receptors (alpha,beta) are primarily responsible for regulating cholesterol homeostasis within cells and the whole body. However, as recent studies show that the role for this receptor is expanding, we studied whether the LXRs could be implicated in bone homeostasis and development. MATERIALS AND METHODS: pQCT was performed on both male and female LXRalpha-/-, LXRbeta-/-, LXRalpha-/-beta-/-, and WT mice at 4 months and 1 year of age. Four-month-old female mice were additionally analyzed with reference to qPCR, immunohistochemistry, histomorphometry, transmission electron microscopy, and serum bone turnover markers. RESULTS: At the mRNA level, LXRbeta was more highly expressed than LXRalpha in both whole long bones and differentiating osteoblast-like MC3T3-E1 and osteoclast-like RAW 264.7 cells. Four-month-old female LXRalpha-/- mice had a significant increase in BMD because of an increase in all cortical parameters. No difference was seen regarding trabecular BMD. Quantitative histomorphometry showed that these mice had significantly more endosteal osteoclasts in the cortical bone; however, these cells appeared less active than normal cells as suggested by a significant reduction in serum levels of cross-linked carboxyterminal telopeptides of type I collagen (CTX) and a reduction in bone TRACP activity. Conversely, the female LXRbeta-/- mice exhibited no change in BMD, presumably because a significant decline in the number of the trabecular osteoclasts was compensated for by an increase in the expression of the osteoclast markers cathepsin K and TRACP. These mice also had a significant decrease in serum CTX, suggesting decreased bone resorption; however, in addition presented with an increase in the expression of osteoblast associated genes, bone formation markers, and serum leptin levels. CONCLUSIONS: Our findings show that both LXRs influence cellular function within the bone, with LXRalpha having an impact on osteoclast activity, primarily in cortical bone, whereas LXRbeta modulates trabecular bone turnover.     

Blood lactate is reduced following successful treatment of anaemia in haemodialysis patients with recombinant human erythropoietin both at rest and after maximal exertion.

The effect of increasing haemoglobin by erythropoietin therapy on exercise capacity was investigated in 11 regular haemodialysis patients, previously transfusion dependent. Exercise work load increased from a median of 100 W (95% confidence limit, 25-135) to 120 (45-180; p < 0.05) following erythropoietin, and the duration of the exercise test from 13 (3.5-20) to 15.5 min (4-22; p < 0.05). Resting blood lactate concentration decreased from 0.8 (0.6-1.6) to 0.3 mmol/l (0.3-0.4), p < 0.05, following treatment with erythropoietin, as did blood lactate concentration at maximal exertion from 2.0 (1.0-4.1) to 1.8 mmol/l (0.5-2.8; p < 0.05). In association with the increase in haemoglobin from a median of 6 (5.1-6.8) to 11.1 g/dl (11-11.9) following erythropoietin therapy, patients were able to achieve greater exercise capacity both in terms of maximum work load and duration of exercise in association with a reduced resting arterial lactate and a similar exercise-induced lactate production. This suggests that treatment had improved muscle function in terms of lactate production and/or utilisation. This was probably due to the increase in tissue oxygen delivery, as there was an increase in the median arterial oxygen content from 79 (65-85) to 150 ml O2 (144-157) following erythropoietin treatment.     

Thumb subungual melanoma: Is amputation necessary?

Subungual melanoma is uncommon. Traditional teaching advocates amputation of the affected digit. Recent studies have shown that more distal levels of amputations do not compromise survival or recurrence rates. When the thumb is involved, functional and aesthetic loss can be substantial. We present a new conservative, digit-sparing approach in the treatment of subungual melanoma of the thumb. Four informed patients were recruited to undergo the new treatment. Local excision with 1cm margins down to and including the periosteum was carried out. Reconstruction was with a local flap. There has been one recurrence and no deaths with a minimum of 6 years follow up. In selected cases, conservative management of subungual melanoma allows preservation of length and minimises disability.     

Preservation and redirection of HPV16E7-specific T cell receptors for immunotherapy of cervical cancer

Human papilloma virus (HPV) type 16 infections of the genital tract are associated with the development of cervical cancer (CxCa) in women. HPV16-derived oncoproteins E6 and E7 are expressed constitutively in these lesions and might therefore be attractive candidates for T-cell-mediated adoptive immunotherapy. However, the low precursor frequency of HPV16E7-specific T cells in patients and healthy donors hampers routine isolation of these cells for adoptive transfer. To overcome this problem, we have isolated T cell receptor (TCR) genes from four different HPV16E7-specific healthy donor and patient-derived human cytotoxic T lymphocyte (CTL) clones. We examined whether genetic engineering of peripheral blood-derived CD8+ T cells in order to express HPV16E711-20-specific TCRs is feasible for adoptive transfer purposes. Reporter cells (Jurkat/MA) carrying a transgenic TCR were shown to bind relevant but not irrelevant tetramers. Moreover, these TCR-transgenic Jurkat/MA cells showed reactivity towards relevant target cells, indicating proper functional activity of the TCRs isolated from already available T cell clones. We next introduced an HPV16E711-20-specific TCR into blood-derived, CD8+ recipient T cells. Transgenic CTL clones stained positive for tetramers presenting the relevant HPV16E711-20 epitope and biological activity of the TCR in transduced CTL was confirmed by lytic activity and by interferon (IFN)-gamma secretion upon antigen-specific stimulation. Importantly, we show recognition of the endogenously processed and HLA-A2 presented HPV16E711-20 CTL epitope by A9-TCR-transgenic T cells. Collectively, our data indicate that HPV16E7 TCR gene transfer is feasible as an alternative strategy to generate human HPV16E7-specific T cells for the treatment of patients suffering from cervical cancer and other HPV16-induced malignancies.