Fourier transform infrared (FT-IR) microspectroscopy is a powerful technique for obtaining chemical information from tissue sections. Infrared spectra can be collected from individual spots or from several spots along a grid pattern. In the latter example, absorbing bands are interpolated between spectra to generate maps that represent the relative concentrations ...

BACKGROUND: Conflicting results have been obtained regarding blood flow distribution to liver tumors. The emphasis on portal vein perfusion has had a great impact on the design of treatment protocols. METHODS: Double microsphere technique with reference organ sampling was used for the measurement of hepatic artery and portal vein blood ...

Radioactive tracers are used in nuclear medicine imaging studies to detect sites of human disease. Use of animal models helps to establish tracer biodistribution kinetics and, thus, is critical to the early testing of radiopharmaceuticals. We developed a method to characterize the premortem temporal, spatial, and compartmental biodistribution of tracer ...

Tissue disposition of perchloroethylene (PCE) was determined experimentally in two mammalian species of markedly different size in order to derive input parameters for the development of a physiologically based pharmacokinetic (PBPK) model, which could forecast the disposition of PCE in each species. Male Sprague-Dawley rats and male beagle dogs received ...

A novel radiofrequency ablative system (40 msec-train pulses with twenty 200 msec pulses at the carrier frequency of 750 KHz and 1 Hz repetition rate) aimed at recanalizing totally occluded peripheral arteries was investigated by means of in vitro tissue ablation from human postmortem arterial wall samples. The samples were ...

Repeat dearterializations seem to be a means to prevent collateral formation, which is partly responsible for the failure of hepatic artery ligation (HAL) or permanent dearterialization when used to treat liver tumors. In this study restoration of tumor blood flow was evaluated after various procedures: HAL (n = 12), permanent ...

The immunosuppressant, SDZ IMM 125 (IMM), is a derivative of cyclosporin A (CyA). The disposition kinetics of IMM in plasma, blood cells, and various tissues of the rat was characterized by a physiologically based pharmacokinetic (PBPK) model; the model was then applied to predict the disposition kinetics in dog and ...

RATIONALE AND OBJECTIVES: A method for measuring the tumor blood flow (TBF) by means of dynamic computed tomography (DCT) was devised and investigated. METHODS: Twenty-seven patients with superficial tumors underwent measurement of TBF by the new DCT method. For all of the 27 patients, the thermal clearance method was employed ...

Bradykinin, infused in low doses (10 micrograms/kg/min) through the carotid artery ipsilateral to RG2 glioma in rats, significantly increased the permeability in tumor capillaries to six different tracers of varying molecular weights compared with intracarotid infusion of saline alone. Permeability in normal brain capillaries was not significantly increased by intracarotid ...

Partition coefficients (PCs) are chemical-specific parameters used in physiologically based pharmacokinetic models to describe chemical solubility in tissues. Tissue:air PCs for volatile chemicals can be estimated using vial equilibration techniques in which the chemical concentration in the vial headspace is measured by gas chromatography after equilibrium is reached between the ...

Gingival biopsy specimens were obtained from 9 smokers and 7 non-smokers during routine flap surgical procedure to investigate the effects of cigarette smoking on gingival epithelium and connective tissue. Although no remarkable histopathological difference was noted between gingival tissues of smokers and non-smokers, but smokers revealed relatively more epithelial keratosis, ...

A computer simulation of radio-frequency (RF) ablation of the endocardium is performed. The objective is to quantify some of the parameters affecting lesion growth, and to obtain theoretical data which can be used as a guide to maximize the lesions obtained with the procedure. The model under consideration consists of ...

Individual polychlorinated biphenyl (CB) congeners in adipose and whole blood tissues of a capacitor manufacture worker (occupational/accidental exposure) and of the general population were determined. Nondestructive sample cleanup and multidimensional gas chromatography-electron capture detection (MDGC-ECD) techniques were applied. Special attention was given to the toxicologically relevant congeners CB-77, CB-126, CB-169, ...

BACKGROUND: Intraarterial hepatic (IAH) administration of verapamil should achieve mdr-1-reversing concentrations with reduced cardiac toxicity. The authors have explored the tolerance of its IAH administration and its effects on doxorubicin pharmacodymamics. METHODS: Verapamil was given to rabbits by intravenous or IAH administration, and its effects on heart rates were compared. ...

A minimally invasive probe and instrument system for real-time measurements of temperature, thermal conductivity and tissue blood flow has been designed for research and clinical use. The essence of the probe is a thermistor, located at the tip of catheters or glass and steel needles, and operating in transient self-heated ...

PURPOSE: To determine whether 5,6-dimethylxanthenone acetic acid (DMXAA), a potent analogue of flavone acetic acid (FAA) inhibits blood flow in mouse mammary tumors, and to assess whether DMXAA enhances the antitumor effects of Tirapazamine (SR 4233) and the novel bioreductive drug SN 23862 (a dinitrobenbenzene mustard). METHODS AND MATERIALS: MDAH-MCa-4 ...

A physiologically based pharmacokinetic (PBPK) model describing transfer of inhaled tetrachloroethylene (PCE) into breast milk with the consequent exposure of the nursing pups was developed and validated in lactating rats. The PBPK model was based on partition coefficients (PCs), which were determined by the equilibration of tissues with known concentrations ...

Adipsin, which is identical to complement factor D, is synthesized by fat cells, circulates in the bloodstream and is profoundly deficient in mice with genetic and hypothalamic obesity. With the recent cloning of human adipsin, a quantitative human immunoassay has been developed. In the present study, we measured adipsin blood ...

After intravenous (iv) injection of 125I-labeled poly(ethylene glycol) (PEG) with different molecular weights to mice, the radioactivity of the organs was measured to pharmacokinetically analyze the body distribution of PEG according to a two-compartment model. High molecular weight PEGs were retained in the blood circulation for a longer period than ...

The dihydropyridine calcium antagonist benidipine hydrochloride (benidipine, KW-3049, CAS 105979-17-7) was intravenously administered to rats under anesthesia with urethane to investigate the effect on regional blood flow in the brown adipose tissue. Benidipine was given at the dose of 100 or 300 micrograms/kg and regional blood flow was measured by ...

A technique for catheterization of a vein draining abdominal subcutaneous tissue and a microdialysis technique that allows measurements of intercellular water concentrations in adipose tissue in humans have recently been described. In the present study, we compare the two techniques during an oral glucose load. In addition a technique using ...

BACKGROUND: Flow-cytometric analysis of proliferation index (PI) has potential use in predicting prognosis in malignancy. Its relevance to heterogeneous tumors has not been conclusively studied. In nephroblastoma, where the epithelial components are considered more differentiated than others, potentially different PIs may exist within a single lesion based on the inverse ...

Sufficient tissue perfusion and oxygenation are vital for all metabolic processes in cells and the major influencing factor of tissue repair and resistance to infectious organisms. The concept of tissue perfusion has been aliked with blood flow, oxygen delivery or a combination of flow and nutritional supply including that of ...

Rat tissue blood flows and heart output were determined in adult Wistar rats under up to two hours of cold (4 degrees C) exposure, using radioactive 46Sc microspheres. Circulating glucose, lactate and triacylglycerol levels were also determined. Glucose concentrations increased with cold exposure in spite of the drainage of substrates ...

PURPOSE: To study the relationship between standardized uptake values (SUVs) in normal tissues and body weight determined with positron emission tomography (PET). MATERIALS AND METHODS: SUVs were determined in 28 nondiabetic women with newly diagnosed untreated primary breast cancers. Body weights ranged from 45 to 107 kg. SUVs for lung, ...

Release of noradrenaline in subcutaneous tissue was measured using a microdialysis technique in combination with an ultrasensitive radio-enzymatic noradrenaline assay. Experiments were performed in conscious dogs with and without tyramine added to the perfusion medium. In the absence of tyramine, the interstitial noradrenaline levels in subcutaneous tissue were similar to ...

1. Microdialysis was used to gain insight into the substrate exchanges in the interstitial space of skeletal muscle and adipose tissue. Probes were inserted in the quadriceps femoris muscle and para-umbilical subcutaneous adipose tissue of thirteen subjects and microdialysis was performed at different flow rates (1-4 microliters min-1) and during ...

A system is described for the in vivo noninvasive measurement of intravascular PO2 at the microscopic level. Under special circumstances the method can also be used to measure interstitial PO2. The PO2 determination is based on the O2-dependent quenching of phosphorescence of palladium-porphyrins bound to albumin. This compound was injected ...

Accurate determination of local blood flow in tissue using the Kety-Schmidt one-compartment model for freely diffusible tracers requires knowledge of the true arterial input function in tissue. Because measured input functions are usually delayed and dispersed with respect to true influx, a correction of the experimental input function is necessary. ...

Blood flow rates to skin and underlying tissues in rats were determined by the radioactive microsphere technique. The dermal and local tissue clearance of two polar solutes, tritiated water and 14C-labeled sucrose, was assessed in anesthetized and sacrificed rats. The dermal clearance of tritiated water in the presence of viable ...

We have developed a new method using fluorescence videomicroscopy to quantitate the extravasation of intravenously injected materials. This method can measure the relative plasma concentration of, and the vascular permeability to, these materials in microcirculatory preparations which contain multiple blood vessels in a field of view. The image of a ...

Little is known about the influence of infiltrating gliomas on the responsivity of the cerebral circulation to anesthetic agents. Therefore we designed a study to address this issue. Male Fischer 344 rats were assigned to two tumor groups and one sham group. In the two tumor groups, glioma cells were ...

The effect of arterial injury on proteoglycans (PG) and their ability to bind low-density lipoprotein (LDL) were studied in rabbits 12 weeks after balloon injury. Following biosynthetic labeling in an organ culture system, PG were isolated under dissociative conditions from deendothelialized areas (DEA), reendothelialized areas (REA), and uninjured areas (control) ...

Traditionally, physiological pharmacokinetic models assume that arterial blood flow to tissue is the rate-limiting step in the transfer of drug into tissue parenchyma. When this assumption is made the tissue can be described as a well-stirred single compartment. This study presents the tissue washout concentration curves of the two opioid ...

Currently, no commercially available system exists to continuously monitor the effective tissue perfusion within the parenchyma of the brain. While several methods exist for accurately measuring cerebral perfusion; among them: 133xeonon clearance, hydrogen clearance and radiolabeled microsphere injection; none of these methods provides continuous monitoring. The Cook Incorporated VH8500 Volumetric ...

BACKGROUND: Basal cell carcinomas (BCC) have increased vasculature, therefore, blood flow within the tumor may be greater than normal surrounding skin. We attempted to detect the difference in blood flow between the tumor and uninvolved surrounding skin utilizing laser doppler velocimetry (LDV). METHODS: Ten patients with 14 BCC were studied. ...

The effects of moderate local hyperthermia (43.3 degrees C/30 min) on regional blood flow and regional ATP distribution in the amelanotic hamster melanoma A-Mel-3 were investigated by high-resolution techniques. Blood flow and ATP concentrations were measured simultaneously in treated and untreated tumors and in adjacent tissues by means of (14C)-Iodoantipyrine ...

Core and organ temperatures in the rat have been found to be subject to regular periodic oscillations (with a frequency of ca 12 cycles per day, i.e. 143 mu Hz) within set limits, by using a chronic thermocouple implant procedure. These cycles consisted of consecutive warming (the temperature increased steadily) ...

We present theoretical simulations of oxygen delivery to tumor tissues by networks of microvessels, based on in vivo observations of vascular geometry and blood flow in the tumor microcirculation. The aim of these studies is to investigate the impact of vascular geometry on the occurrence of tissue hypoxia. The observations ...

This laboratory has previously used a window chamber model to measure red blood cell velocity in mammary tumors and normal granulation tissues of the F-344 rat. Because red cell flux and hematocrit more accurately reflect the oxygen carrying potential of blood, we used this model to measure these parameters. Red ...

This paper describes an experiment technique for the measurement of thermal conductivity, thermal diffusivity and perfusion using self-heated thermistors. Thermal probes are constructed by placing a miniature thermistor at the tip of a plastic catheter. The volume of tissue over which the measurement occurs depends on the surface area of ...

We describe a new technique for the analysis of dynamic positron emission tomography (PET) studies in humans, where data consist of the time courses of label in tissue regions of interest and in arterial blood, following the administration of radiolabelled tracers. The technique produces a simple spectrum of the kinetic ...

rac-Bupivacaine HCl was infused intravenously to constant arterial blood drug concentrations in sheep using a regimen of 4 mg/min for 15 min followed by 1 mg/min to 24 h. At 24 h, arterial blood was sampled, the animal was killed with a bolus of KCl solution, then rapidly dissected and ...

We have measured total blood flows and blood flows per 100 g tissue to major tissues at 120 and 140 days gestation in fetal sheep and at 3 and 21 days of age in lambs (gestation period = 144 +/- 2 days). Between 120 and 140 days gestation, flow per ...

During the past 13 years, a number of prostheses of differing design and tissue seals have been used in laser stapedotomy for otosclerosis. This study compares the results of three different configurations of prostheses and tissue seals in a series of 53 patients. In 19, a platinum wire Teflon piston ...

BACKGROUND: Some studies suggest that nutritional blood flow and intratumor levels of high-energy phosphates such as adenosine triphosphate (ATP) affect tumor response to treatment. Reports of intratumor variabilities have shown that distribution of high-energy phosphates within experimental and human tumors is not uniform, and this variability may be related to ...

2H-Nuclear magnetic resonance imaging of deuteron accumulation in tissue following an i.v. bolus of deuterium oxide provides a noninvasive means of constructing maps of tissue perfusion. With a measured arterial input function and a simple model for tissue-capillary exchange, these data can provide quantitative estimates of local flow. This technique ...

Subcutaneous adipose tissue blood flow (ATBF) was measured by the local clearance of 133Xe from the abdominal and femoral regions of nine individuals with non-endocrine obesity before and after seven days of fasting. Fifteen non-obese individuals served as controls. In the obese group ATBF was similar in the abdominal and ...

RATIONALE AND OBJECTIVES: High-intensity focused ultrasound (HIFU) is the only radiation beam that can remotely destroy deep-seated tissue targets without causing damage to the intervening tissues. This study evaluates the ability of sonography-guided HIFU to extracorporeally induce liver ablation in a rabbit model. METHODS: Under sonographic guidance, the HIFU beam ...

In order to elucidate the mechanism for appearance of no-flow areas (areas where tumor blood flow temporarily cease), we directly observed the process of tumor-induced neovascularization and measured pressure change in a feeding vessel (starting vessel) which supplies blood to the tumor vascular network. Total length of tumor vascular network ...