Effects of the vasoconstrictor angiotensin II on tumour microvascular perfusion and oxygenation were examined in the murine SCCVII carcinoma grown subcutaneously in C3H/He mice. Angiotensin II infusion (2 micrograms/kg/min) caused an increase in mouse arterial blood pressure from 85 (2) mm Hg (mean, S.D.) to 112 (7) mm Hg. During ...

Ochratoxin A is suspected of being one of the etiological agents responsible for Balkan endemic nephropathy and the associated urinary tract tumours. Contamination of cereals by this mycotoxin has been found to be more frequent in areas of endemic nephropathy than in areas where the disease is absent. As ochratoxin ...

The inferior epigastric venous flap of the rat was chosen for experimental studies of vascular flow alterations. The long saphenous vein was not selected for use; preliminary studies involving forced retrograde injection demonstrated that it drains blood primarily from the leg and foot, not from its overlying skin. Eight different ...

Vinblastine or colchicine, administered intraperitoneally to B6D2F1 mice with advanced subcutaneous colon 38 tumours, induced substantial tumour growth delays with progressive development of haemorrhagic necrosis beginning within 8 hours of treatment. Two multidrug-resistant P388 leukaemia sublines, refractory to vinblastine and vincristine when grown as intraperitoneal ascites, were sensitive to necrosis ...

Experimental DMBA (7,12-dimethylbenzanthracene)-induced mammary tumours in Sprague-Dawley rats are studied. Percentages of the distinct types of adenocarcinomas (Stevens et al. 1965) were as follows: type A (poorly-differentiated), 8.8%; type B (well-differentiated), 65.5%; type C (atrophic), 15.5% and type D (secretory), 5.4%. 51% of the mammary adenocarcinomas were seen to be ...

In an experimental study to test the thromboxane (TX) synthetase inhibitor OKY-046, two random-pattern skin flaps, each measuring 15.5 x 2 cm, and caudally based, were elevated on the backs of rabbits, and the effect of the test drug on their survival length was evaluated. The results indicated that the ...

Regional nutrient blood flow to musculocutaneous and fasciocutaneous flaps was studied in dogs using 15-microns radiolabeled microspheres, and correlations to bacterial inoculation into closed wound spaces were sought. During the 6-day study period, no differences were found between blood flow to noinoculated versus inoculated flaps. Comparisons of blood flow to ...

The range of disorders affecting the cerebral veins and sinuses is increasing and now includes blood disorders, abnormalities in the patterns of blood flow, and infiltrative or inflammatory conditions, all of which may promote thrombosis. We describe 10 patients with cerebral venous thrombosis: two had protein S deficiency, one had ...

A TSI laser Doppler flowmeter was used via a rigid sigmoidoscope in 20 consecutive patients with rectal carcinoma. Blood flow and velocity was evaluated at the tumour centre, tumour edge and adjacent normal mucosa; blood flow in the centre of the tumour was significantly higher than in normal mucosa (P ...

Perfusion and viability of island axial pattern skin flaps were tested in 37 healthy New Zealand white rabbits, using laser Doppler monitoring of blood flow in the capillary loops and the subpapillary plexus of the dermis. Skin flaps, selected on the basis of the caudal superficial epigastric vein and artery, ...

The effect of increased and decreased uniaxial tissue tension on capillary blood flow, plasma volume, edema formation, and vascular permeability in myocutaneous flaps was studied. A total of 64 equally sized arterialized myocutaneous flaps were outlined on the abdomen of 16 dogs. The four areas on each dog were randomized ...

Two aspects of the inflammatory response to infection--blood flow alteration and leukocyte mobilization--are investigated in the canine model. The elevation of paired musculocutaneous (MC) and random pattern (RP) flaps allowed comparison of healing flaps with significant differences in blood flow (lower in random pattern flaps) and resistance to infection (greater ...

The aim of the study was experimentally to evaluate the capability and reliability of laser Doppler flowmetry (LDF) in conditions of circulatory deficiency, by correlating it to flow-related parameters measured by a radionuclide-imaging technique and using 99m-Tc red blood cells (RBCs). For this purpose, a pedicle island flap in the ...

Sodium fluorescein is an in vivo blood perfusion indicator for soft tissue. When fluorescein dye is introduced into the blood, it distributes throughout the vasculature and the extravascular space. Incident light from an external source causes the dye to fluoresce, the level of which is monitored by a photodetector placed ...

Angiogenesis is the term used to describe the formation and development of blood vessels. The renewed interest in regulation and mechanistic aspects of angiogenesis depends on advances in the comprehension of metastatic dissemination of cancers, ischaemic heart disease and blood-brain barrier formation. Recently, many poly-peptide growth factors have been discovered ...

A porcine rectus abdominis musculocutaneous (TRAM) flap model was designed and validated in nine pigs. This TRAM flap was based on the deep inferior epigastric (DIE) vessels with an 8 x 18 cm transverse skin paddle at the superior end of the rectus abdominis muscle. The model was subsequently used ...

Hydralazine has been shown to reduce tumour blood flow and to potentiate the cytotoxicity of melphalan and bioreductive agents in mice. In order to determine whether such a strategy might have clinical potential, a study was undertaken to investigate the effects of hydralazine on blood flow through human tumours. Twenty-two ...

An island skin flap was designed on the left inferior epigastric neurovascular bundle of anesthetized male rats. Blood flow was measured in situ with a laser Doppler flowmeter at 20 discrete points on a grid system (5 points in each quadrant of the flap) before and after surgery, or before ...

Blood flow and phosphorus metabolites have been measured simultaneously in the murine RIF-1 tumour in vivo. Blood flow was measured using the H2 washout technique and 31P NMR spectroscopy was used to measure high energy phosphates, inorganic phosphate and intracellular pH within the tumour. Following NMR and flow measurements, hydralazine ...

Temporary restoration of capillary skin blood flow can be established by using leeches or by the creation of a dermal wound and the promotion of continued bleeding from the wound site in a flap with venous occlusion. An increasing restoration of capillary flow occurred with initial application of the leech ...

The rabbit epigastric free flap, subjected to 21 hours of warm (25 degrees C) ischaemia, was used as an experimental model to test the ability of two endothelium-dependent vasodilators, calcitonin gene-related peptide (CGRP) and carbamyl beta-methylcholine chloride (MCh, bethanechol chloride, the stable acetylcholine analogue) to improve flap viability. After the ...

In a review of 20 gracilis flaps in 18 patients, variations in flap viability have been found. In response to these findings, a detailed anatomical study was performed in 15 fresh cadavers. Selective dye injections evaluated the limits of the skin paddle depending on the dominant pedicle. Most of the ...

The medicinal leech, Hirudo medicinalis, has been recognized by plastic surgeons for its ability to reduce congestion and improve blood flow in grafted skin flaps by withdrawing excess blood. The leech's ability to digest blood is due to the presence of Aeromonas hydrophila in the gut of the leech. In ...

In previous studies using rabbit ears, total venous perfusion flaps (TVPF) were used that did not contain in the experimental model any chosen arteries truly representative of clinical venous flaps. We discovered that the TVPF could survive even under conditions of poor blood circulation. In the present study, conditions of ...

Blood flow patterns have been studied in 28 patients with soft tissue sarcoma (29 tumours) using 99mTc-labelled hexamethyl propyleneamineoxime with planar views of the tumour-bearing region. Tumour:background ratios ranged from 1.13 to 6.60 (mean 2.74) and maximum:minimum tumour ratios (between peripheries and centres of tumours) ranged from 1.34 to 32.0 ...

Laser Doppler flowmetry is a simple method of determining, directly and continuously, tissue blood flow. However, its applicability to monitoring tumour blood flow interstitially during hyperthermia treatments is still being evaluated. The purposes of this study were to physically characterize the measurement probes, to evaluate potential sources of artifact with ...

Blood flow measurements following i.v. infusion of iodo-antipyrine labelled with 14C(14C-IAP) and blood volume measurements following i.v. injection of 125I human serum albumin and 51Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14C-IAP was found to ...

In vivo 31P-NMR spectroscopy was used to monitor the energy metabolism, apparent intracellular pH (pHNMR), and phospholipid turnover in subcutaneous fibrosarcomas (FSall) and mammary carcinomas (MCaIV) treated with hyperthermia (HT). Treatment consisted of elevation of tumour temperature to 43.5 degrees C for 15, 30 or 60 min (FSall) and 30 ...

Previous reports and our findings suggest that resection by ultrasound is of appreciable merit in liver surgery. Blood can be saved and bile leakage diminished as the larger vessels and bile ducts can be skeletonized unharmed, whereas the dissector selectively carries away the parenchyma. Otherwise virtually inaccessible tumours can be ...

Laser angioplasty systems with laser energy preferentially absorbed by atherosclerotic plaque may offer a safe method of plaque removal. This study evaluated the effect of blood upon selective energy absorption using a pulsed dye laser at 480 nm. Intra-arterial laser irradiation of normal rabbit femoral arteries demonstrated a perforation threshold ...

Intracarotid infusions of leukotriene C4 (LTC4) were used to selectively open the blood-tumour barrier in rats with RG-2 gliomas. Blood-brain and blood-tumour barrier permeability was determined by quantitative autoradiography using 14C aminoisobutyric acid. LTC4 (4 micrograms total dose) infused into the carotid artery ipsilateral to the tumour increased the unidirectional ...

Five patients with various types of brain tumours were infused with x-ray contrast material in a schedule designed to maintain a constant plasma concentration of tracer over a period of 3 hours. CT scans from an equatorial section of the tumour were taken at frequent intervals the first hour; then ...

This study was designed to investigate the use of heparinized whole blood as a perfusate for extending the tolerable ischemic interval of free flaps. Unilateral free groin flaps stored at 20 degrees for 30 hr were used in four groups of 12 rats each. One group served as a control ...

Blood flow was measured in the skin flaps of 20 patients who had undergone reconstructive surgery. All flaps were showing clinical signs of deficient circulation. Local blood flow in skin flaps was significantly increased by electrical nerve stimulation (ENS) (p less than 0.001), but not by placebo ENS. Repeated ENS ...

We investigated the suitability of BMDP and SAS as an integrated tool for the evaluation of regional blood flow data obtained from the radioactive microsphere technique. Both packages were applied to a recent study on muscle blood flow with a 3-factorial design. The organization of data and files, the strategy ...

The changes in pH and blood flow of tumours caused by hyperglycaemia, and their effects on hyperthermia with BCNU, were investigated using RIF-1 tumours which grew intradermally in the thigh of C3H mice. The pH of the tumour was measured by inserting a microelectrode into the tumour. The blood flow ...

A four-applicator phased-array hyperthermia system with movable apertures (MA) is compared with an eight-applicator annular phased-array hyperthermia system with fixed apertures (AA) in terms of the HEP (hyperthermia equipment performance) values, based on two-dimensional models and the bioheat transfer equation. A hybrid element method is used to calculate the zeta-directed ...

Solid tumour growth was hypothesized by Folkman (1976) to take place in two phases: the avascular phase and the vascular phase. In the first (avascular) phase, the tumour obtains its nutrients and disposes of its metabolic wastes by diffusion transport processes alone. Since the mechanism for growth is diffusion-limited, these ...

Computer simulations and error analysis of a simple two-compartment, passive-diffusion exchange model for 82Rb across the blood-brain-barrier (BBB) have demonstrated the feasibility of obtaining useful estimates of unidirectional rate constant (K1) and tissue-blood water volume (Vb) in vivo using dynamic positron tomography (PET). The coefficients of variation (CV) in parameter ...

Tumour blood flow was estimated by fractional distribution of rubidium in two allografts (B16 melanoma and Lewis lung tumour) and two xenografts (Glioma 522, a human grade IV astrocytoma and Mel-mo, a human melanoma), in order to investigate the influence of certain tumour characteristics on tumour perfusion. In all four ...

The influence of altered tumour oxygenation on the responses to radiation and/or bioreductive 2-nitroimidazole compounds was studied in a well differentiated, human, colon adenocarcinoma (MAWI), grown as a subcutaneous xenograft in nude mice. Tumour growth delays were measured after local, single 5-18 Gy doses of X-rays. BW12C, which inhibits dissociation ...

Island pedicle flaps with a proximal well-perfused part and a distal poorly-perfused part were raised in eight anaesthetized sheep. Autologous red blood cells were labelled in vitro with 99TcmO4 and plasma with 111In chloride. The labelled cells and plasma were injected intraarterially and both dynamic and static images of the ...

Two patients with an ear defect, each reconstructed with a reverse-flow postauricular arterial flap are presented; one defect was caused by accidental exposure of bare cartilage at the posterior helix and the other by traumatic loss of earlobe. After the flaps were transposed, a line of auditory signals was dictated ...

The sites of intra-embryonic haemopoiesis of the chick embryo (stages 15-26) preceding the initiation of hepatic haemopoiesis was investigated by means of serial sections stained with azan liquid. Hitherto undescribed blood islands of large size and clear outline were found in the neck and lateral body fold of the embryo. ...

Circulatory and metabolic skin-flap events were studied prior to and up to 6 hours after elevation of buttock island flaps in pigs. During the elevation, significant reductions in superficial skin blood flow, measured by laser Doppler flowmetry (LDF) and dermal flap temperature, were seen. Significant correlations were found between blood ...

A new experimental skin-flap model is presented in which direct observations of blood flow in individual capillaries can be made from the time of flap creation throughout the entire evolution of the establishment of necrosis. After flap creation, one observes through the microscope that at 1 hour a large area ...

The subcutaneous blood flow (SBF) was measured by the 133Xe washout method in the scalp of 14 patients with early male pattern baldness. Control experiments were performed in 14 normal haired men matched for age. The SBF in the scalp of the normal individuals was about 10 times higher than ...

The effect of 70 mgkg-1 BW12C 30 min before heating on the thermosensitivity of RIF-1 leg tumors was studied. This schedule is known to increase the hypoxic fraction by a factor of 5. Heating, using a combined radio-frequency and saline bath technique, was for 30 min at 43, 43.5, and ...

The dye fluorescence index (DFI) has been cited as an accurate predictor of skin-flap survival. However, two thresholds, one each for flap survival and flap necrosis, have been advocated. A DFI of less than 15 to 20 percent predicts failure, and a DFI greater than 35 to 50 percent predicts ...

The assessment of thoracic blood flow by electrical impedance is a well-established technique. In an application of this a small electrode array has been developed in which an alternating electric current is passed through a subcutaneous free flap and the induced voltage across a small volume measured. A graphical display ...