Effect of diabetes on the cutaneous microcirculation of the feet in patients with intermittent claudication.

AIMS: To evaluate endothelial-dependent and - independent cutaneous vasodilator responses in the feet of patients with peripheral arterial disease (PAD) with or without Type 2 diabetes. METHODS: Cutaneous microvascular responses in the dorsum of both lower limbs were measured in the supine position using Laser Doppler Fluximetry combined with iontophoretic administration of endothelial-dependent (acetylcholine, Ach) and -independent (sodium nitroprusside, SNP) vasodilators in diabetic (n = 19) and non diabetic (n = 17) patients with PAD (presenting as unilateral calf intermittent claudication (IC). RESULTS: In patients with diabetes and IC, endothelial-dependent vasodilation was significantly impaired in the symptomatic limb [74 (57,105) vs 68 (24,81) PU, Z =-2.79, p = 0.005] compared to the asymptomatic limb. Patients without diabetes showed no impairment of vasodilation. Resting ankle-brachial pressure index did not identify the presence of abnormalities in microvascular function. CONCLUSIONS: The combination of diabetes and PAD is associated with a reduction in endothelial-dependent cutaneous vasodilation in the feet without an associated reduction in endothelial independent vasodilation.

Contrasting effects of varicose vein surgery on endothelial-dependent and -independent cutaneous vasodilation in the perimalleolar region.

OBJECTIVES: To evaluate the effects of varicose vein surgery on cutaneous microvascular perfusion and vasodilator responses to acetylcholine (Ach) and sodium nitroprusside (SNP) in the gaiter area of patients with great saphenous vein insufficiency. METHODS: Twenty-nine patients with isolated great saphenous vein incompetence attended three study mornings (before surgery, and 6-8 weeks and 6 months after sapheno-femoral ligation+partial stripping) during which cutaneous microvascular responses were measured in the supine and standing positions using laser Doppler fluximetry (LDF) combined with incremental-dose iontophoretic administration of endothelial-dependent (Ach) and -independent (SNP) vasodilators. RESULTS: Varicose vein surgery had no significant effect on baseline cutaneous perfusion or the microvascular response to Ach: e.g. peak vasodilator responses to the 1000 microC stimulus were mean 58 SEM 7, 64 SEM 6 and 65 SEM 7PU on the pre-operative, 6-8 weeks and 6 months assessments. In contrast, the corresponding responses to SNP were significantly increased following surgery: e.g. at 2000 microC, mean 63 SEM 9, 142 SEM 4 and 157 SEM 9PU (p<0.0001) in the upright position. CONCLUSIONS: Sapheno-femoral ligation and partial stripping in patients with great saphenous vein insufficiency improves endothelial-independent cutaneous vasodilator function at the gaiter area, which may at least partly explain the benefits of surgery in reducing the risk of venous ulceration.

Anesthesia for endovascular repair of abdominal and thoracic aortic aneurysms: a review article.

Open repair of abdominal aortic aneurysms (AAA) and thoracic aortic aneurysms (TAA) are associated with significant morbidity and mortality. Endovascular aortic aneurysm repair (EVAAR) using a stent graft is a new alternative to traditional open repair. There are various types of anesthesia which can be utilized for EVAAR; specifically general endotracheal anesthesia, regional anesthesia, and monitored anesthesia care (MAC) with local anesthetic infiltrated at the incision site. Choice of anesthetic technique may be dependent upon a patient's co-existing diseases. We have prepared a review article discussing the various types of anesthesia available for this procedure, including the specifics of each technique and pros and cons of each option. The most often utilized technique appears to be general anesthesia, often times related to surgeon unfamiliarity with the EVAAR procedure. Regional techniques, including continuous epidural or continuous spinal anesthesia are utilized in some cases with very good results. This technique can provide more hemodynamic stability and better pain control than general alternative, MAC with local, is an extremely safe and effective technique for the EVAAR procedure, especially in patients with severe co-existing diseases. In addition, this technique also minimalizes sedation and post-operative analgesic requirements, decreases cardiopulmonary complications, and decreases overall hospital stay, thereby reducing cost.

Effects of posture and venous insufficiency on endothelial-dependent and -independent cutaneous vasodilation in the perimalleolar region.

OBJECTIVES: To assess the effects of posture, endothelial function and venous insufficiency on cutaneous microvascular vasodilator function in the gaiter area, in particular defining factors which may affect microangiopathy and ulcer formation. METHODS: Endothelial-dependent and -independent vasodilator responses to incremental-doses of acetylcholine (Ach) and sodium nitroprusside (SNP) were evaluated in the perimalleolar region in the supine and standing positions in middle-aged patients with isolated superficial venous insufficiency (ISVI) (n = 25) and healthy controls (n = 28) using laser Doppler fluximetry (LDF) and iontophoresis of vasodilators. RESULTS: The venoarteriolar reflex (vasoconstriction on standing) was equally present in both groups, and reduced the vasodilator responses to SNP in the upright position (e.g., for patients with ISVI, peak SNP response was 82 +/- 11 PU [standing] vs 123 +/- 15 PU [supine]). The presence of ISVI had no effect on endothelial vasodilator function in the supine position, but on standing cutaneous reactivity to Ach was significantly reduced (e.g., peak Ach response 69 +/- 8 PU [ISVI] vs 109 +/- 11 PU [controls], p < 0.003). CONCLUSIONS: Upright posture impairs cutaneous endothelial-dependent vasodilation in the gaiter area of patients with ISVI. This may be of clinical and prognostic utility in identifying which patients with uncomplicated ISVI are at highest risk of tissue breakdown and ulcer formation in the gaiter area.

Mutational status of overexpressed p16 in head and neck cancer: evidence for germline mutation of p16/p14ARF.

Inactivation of the p16 tumor suppressor gene is a common phenomenon in squamous cell carcinoma of the head and neck (SCCHN). Less commonly described is the observation of p16 overexpression in SCCHN. Since overexpression of p16 is a potent predictor of outcome in other cancers, we were interested in determining the level of expression of p16 in our SCCHN specimens as a prerequisite to later prognostic studies. We were also interested in determining the mutational status of p16 in these tumors, in order to determine whether the combination of overexpression and gene alteration may predict a different clinical outcome from overexpression alone. A total of 84 specimens of SCCHN were selected for study. These specimens were obtained from all major sites within the oral cavity, oropharynx, pharynx and larynx. The level of expression of p16 in SCCHN specimens was measured by semi-quantitative RT-PCR. In 35 cases, RNA was also isolated from matched normal tissue obtained from a negative tumor margin. In the other 49 cases, the expression level was compared with the level of expression measured in pooled normal RNA obtained from 10 specimens of normal epithelial tissue. Overexpression of p16 was documented when the level of expression in the tumor specimen was 2-fold or greater above the level of expression found in normal tissue. A total of 46 specimens demonstrated overexpression of p16 (55%). All specimens demonstrating overexpression were then subject to sequence analysis. Thirty specimens (65%) showed p16-specific gene alterations, ranging from intragenic deletions to single point mutations, and 15 of these cases concomitantly affect p14ARF. A single specimen demonstrated a silent point mutation within the p16 reading frame. This mutation produces a stop codon at residue 85 in the context of the p14ARF reading frame, predicting premature termination of p14ARF within a previously determined nucleolar localization signal. This observation suggests that in some cases at least, p14ARF may be a selective target for alteration, independently of p16. Analysis of a normal tissue specimen obtained from a negative tumor margin, and a blood sample obtained approximately five years after surgery indicate that this p14ARF-specific alteration may represent a germline mutation.

Angiographic embolisation in the management of pelvic haemorrhage.

Haemorrhage from pelvic veins during obstetric and gynaecological surgery is a major cause of morbidity and mortality. In a recent commentary entitled The Seven Surgeons of King's: a fable by Aesop(1), surgeons from different specialties used techniques peculiar to their own practice to treat a woman with intractable haemorrhage. Could transcatheter arterial embolisation be the 'eighth surgeon'? We describe two cases where embolisation was used to control bleeding when local surgical measures had failed and discuss the use of embolisation in obstetrics and gynaecology.

Subcutaneous urinary diversion: an alternative to percutaneous nephrostomy.

Nephrostomy has been the standard method of urinary diversion when placement of ureteral stents has failed in cancer patients. We describe our early experience with an alternative method of urinary diversion, the subcutaneous urinary diversion. This extra-anatomical urinary diversion was done in 5 patients during a 15-month interval. The diversion is created using a specially designed 7F double pigtail stent. The proximal end of the stent is inserted into the renal pelvis via a percutaneous nephrostomy puncture. A subcutaneous tunnel is created from the flank to the bladder down which the distal end of the stent is passed and via a suprapubic bladder puncture the stent is passed into the bladder. The stent is changed at 4-month intervals over a guide wire. Our early experience with this extra-anatomical method of urinary diversion suggests it to be a safe, effective and acceptable alternative to nephrostomy that improves quality of life.