Showing papers by "Rakesh K. Jain published in 1992"

Microvascular Pressure Is the Principal Driving Force for Interstitial Hypertension in Solid Tumors: Implications for Vascular Collapse

Abstract: The interstitial fluid pressure (IFP) has been found to be as high as 20 to 50 mm Hg in both experimental and human solid tumors. While the IFP is an important determinant of the delivery of therapeutic agents to neoplastic cells in vivo, the mechanisms responsible for interstitial hypertension are not completely understood. The high vascular permeability of tumor blood vessels and the absence of a functional lymphatic circulation suggest that the hydrostatic microvascular pressure (MVP) is the main force governing IFP in tumors. To test this hypothesis, we simultaneously measured IFP and MVP in 13 tissue-isolated R3230AC mammary adenocarcinomas transplanted in rats. The MVP in superficial postcapillary venules of diameters between 25 and 250 microns was measured with the micropuncture technique. MVP was compared to the IFP in the periphery (measured with micropuncture technique) and in the center (measured with wick-in-needle technique). Similar to our previous study, IFP rose rapidly and reached maximum values at a depth of 0.2 to 1.0 mm from the tumor surface. These maximum IFP values [16.5 +/- 7.1 mm Hg (SD)] were equal to IFP in the tumor center [18.4 +/- 9.3 mm Hg] [R2 = 0.86, P greater than 0.8]. Superficial MVP (17.3 +/- 6.1 mm Hg) was equal to both central (P greater than 0.9) and superficial IFP (P greater than 0.7). These results demonstrate that the main driving force for IFP in tumors is the MVP. Furthermore, the concept that blood vessel collapse is induced by higher hydrostatic pressures in the tumor interstitium compared to that in the vascular lumen is not supported by the present finding that elevated IFP is accompanied by equally elevated MVP.

Angiogenesis, Microvascular Architecture, Microhemodynamics, and Interstitial Fluid Pressure during Early Growth of Human Adenocarcinoma LS174T in SCID Mice

Abstract: To date, most quantitative information on tumor angiogenesis, microcirculation, and transport has been derived from rodent tumors grown in transparent chamber preparations. In this paper we present a chamber technique adapted to immunodeficient mice for the study of human tumor xenografts. Microcirculatory parameters in severe combined immunodeficient mice bearing a dorsal skin fold chamber preparation were quantified using intravital microscopy and image analysis. The take rate of the human colon adenocarcinoma LS174T in the chamber preparation was 100%, and the tumor area doubling time was 6.5 days. Three days following implantation of 2 x 10(5) tumor cells onto the striated skin muscle, capillary sprouts were noted in the tumor cell mass. Microvasculature in the tumors was established after 10 days. Capillary density, vessel diameter, red blood cell velocity, and blood flow rates in individual microvessels measured on days 10, 14, 18, and 22 showed no statistical difference in the striated muscle (capillaries) and subcutaneous tissue (arterioles and venules) of the skin of tumor-free animals (N = 6), whereas these parameters increased slightly, but not significantly, in the LS174T tumors (N = 7). Mean interstitial fluid pressure (+/- SD) in these small tumors was 4.6 +/- 1.7 mmHg (N = 4) on day 10 and 5.1 +/- 0.9 mmHg (N = 4) on day 22 and significantly elevated compared to that in the subcutaneous and skin tissue (-0.9 +/- 0.8 mmHg) (N = 4) (P < 0.001). To our knowledge, this is the first model enabling intravital microscopic studies of human tumor xenografts in a transparent chamber preparation in severe combined immunodeficient mice. Studies on angiogenesis, microcirculation, and transport using such a preparation should provide new insights into microcirculation-mediated mechanisms for cancer treatment.

Interstitial Hypertension in Human Breast and Colorectal Tumors

Abstract: The efficacy of present day antineoplastic regimens depends upon the delivery and penetration of therapeutic agents through the tumor vascular and interstitial spaces to the tumor cell target The distribution of relevant molecules or cells in a solid tumor is often poor and heterogeneous and is believed to be due to a number of pathophysiological factors, including elevated interstitial fluid pressure (IFP) Using the wick-in-needle technique, IFP was measured in primary breast and colorectal carcinomas as well as their respective metastases to the lymph nodes and liver in a total of 17 patients IFP was also measured in one recurrent renal cell carcinoma, one melanoma metastasis to the lymph nodes, and another melanoma metastasis to the lung IFP varied from 4 to 50 mm Hg with a mean +/- SD of 20 +/- 13 mm Hg in the neoplasms (n = 41 measurements; n = 21 tumors), while IFP in normal tissues had a mean of 2 +/- 4 mm Hg (n = 11) The mean IFPs for metastatic melanoma, primary breast carcinoma, and liver metastases from a colorectal primary were found to be 33 +/- 14, 15 +/- 9, and 21 +/- 12 mm Hg, respectively In the renal cell carcinoma, the pressure was 38 mm Hg These results agree with the findings of our 3 previous studies examining IFP in human superficial melanomas (143 +/- 125 mm Hg, n = 12), cervical carcinomas (157 +/- 57 mm Hg, n = 12), and head and neck tumors (132 +/- 88 mm Hg, n = 19), and indicate that in all types of human tumors studied to date, IFP was significantly elevated above that of normal tissue This observation may be useful in localizing tumors during needle biopsy

Interstitial Hypertension in Head and Neck Tumors in Patients: Correlation with Tumor Size

Abstract: Elevated interstitial fluid pressure (IFP) is associated with poor blood supply and inadequate delivery of drugs to solid tumors. IFP was measured in squamous cell carcinomas of the head and neck region in humans using the wick-in-needle technique. In all lesions (n = 19), the IFP was elevated (4-33 mm Hg). Furthermore, the IFP increased with tumor size. The highest IFP was 33 mm Hg in a 24-ml tumor. In one tumor, the IFP was found to be negative (-2.6 mm Hg), which is comparable to that in human skin or subcutaneous tissue. The histopathology of this tumor was benign. If this pressure difference between malignant and benign lesions can be confirmed in a large number of tumors, then the IFP could be used to aid tumor detection during needle biopsy. The value of IFP as a predictor of response to radiotherapy, photodynamic therapy, hyperthermia, and chemotherapy should be assessed prospectively.

Effect of bivalent interaction upon apparent antibody affinity: experimental confirmation of theory using fluorescence photobleaching and implications for antibody binding assays.

Abstract: The affinity of a monoclonal antibody for its tumor-associated antigen is one of several parameters governing in vivo monoclonal antibody distribution. However, there is a lack of apparent correlation between the affinity of a bivalent monoclonal antibody measured using equilibrium binding experiments and its in vivo delivery. Furthermore, differences in the reported affinity for identical antibody/antigen pairs are quite common in the literature. In this paper, both of these discrepancies are addressed in terms of variation in avidity due to bivalent interaction. The enhancement of avidity afforded by bivalent attachment is addressed theoretically by extending the model of Crothers and Metzger (Immunochemistry, 9: 341-357, 1972). Theoretical assessment of Lineweaver-Burk, Scatchard, Steward-Petty, Langmuir, fluorescence recovery after photobleaching, and Sips models demonstrates quantitatively that the measured affinity using equilibrium binding experiments may vary over four orders of magnitude with similar variation in experimental cellular antigen density. Further, the measured affinity is a function of the experimental protocol. Predictions of avidity enhancement were confirmed experimentally using fluorescence recovery after photobleaching. These experiments measured the equilibrium binding constant and concentration of binding sites for an immunoglobulin G monoclonal antibody and its F(ab) fragment directed against the rabbit VX2 carcinoma cell line. Bivalent binding data agree quantitatively with those predicted by the bivalent model with no adjustable parameters. It is concluded that bivalent equilibrium binding constants are useful only in antibody screening, where experimental conditions are identical for all series. They must be used with caution in predicting in vivo antibody distribution, and it is recommended that the intrinsic, monovalent affinity be measured in tandem with any bivalent antibody study as a standard reference.

Interstitial fluid pressure in solid tumors following hyperthermia: possible correlation with therapeutic response.

Abstract: Elevated interstitial fluid pressure (IFP) of tumors may be a physiological barrier to the delivery of certain therapeutic agents. The objective of this study was to find out if IFP could be lowered using localized hyperthermia and if the reduction in IFP could predict the tumor response to treatment. Amelanotic melanoma (A-Mel-3) implanted into the dorsal skin of Syrian golden hamsters was exposed to hyperthermic treatment after 7 days of tumor growth at tumor volumes of about 100-150 mm3. Hyperthermia was induced by immersing the tumor in a water bath at 43 degrees C for 30 or 60 min. Forty-eight h later the IFP of control and treated tumors was determined by using the wick-in-needle technique. The mean IFP in control tumors was 12.6 mmHg. Hyperthermic treatment for 30 min induced a significant decrease to 2.8 mmHg (P less than 0.001 versus controls), whereas a 60-min immersion of the tumors induced a further decrease to 0.8 mmHg (P less than 0.05 versus 43 degrees C for 30 min). Separate experiments on tumor growth in corresponding groups of animals revealed a significant growth delay of 2.7 days after hyperthermia for 30 min. Enhanced growth delay and partial tumor response in 66% of the tumors were found following 60 min of hyperthermia at 43 degrees C. The thermal dose-dependent decrease in IFP presumably results from the dose-dependent damage to the tumor vasculature. In addition, the association of an enhanced biological effect with a more pronounced reduction of interstitial fluid pressure suggests that the IFP might serve as a quantitative parameter to predict the response of tumors to hyperthermic therapy.

Nicotinamide Can Lower Tumor Interstitial Fluid Pressure: Mechanistic and Therapeutic Implications

Abstract: Several investigators have shown that nicotinamide (NA) may increase the tumor blood flow and/or alleviate temporal fluctuations in tumor blood flow and, consequently, increase pO2. However, the mechanisms of these changes in tumor blood flow are not understood, especially because NA lowers the mean arterial blood pressure in mice. Our hypothesis is that NA may decrease flow resistance in tumors, which would lower vascular pressure and tumor interstitial fluid pressure (TIFP). To test this hypothesis, we measured the physiological parameters: mean arterial blood pressure, TIFP, tumor water content, and hematocrit in C3H mice bearing FSaII tumors, before and after treatment with 500 mg/kg of NA. In control animals, TIFP increased with tumor growth up to 400 mm3, reached a plateau, and then decreased when the tumor size was above 1000 mm3 (n = 135). Tumor water content correlated significantly with TIFT (for tumors less than 500 mm3) (n = 26). NA caused approximately a 15% decrease in mean arterial blood pressure (P less than 0.05) and a 35% decrease in TIFP (P less than 0.001) at 2 h postinjection, without any change in hematocrit. The change in TIFP was found to be tumor size dependent. Specifically, NA decreased the TIFP by 47% (P less than 0.001) and 39% (P less than 0.001) in medium (200 to 500 mm3) and large (500 to 800 mm3) tumors, respectively. The decrease in TIFP in small (less than 200 mm3) and very large (greater than 800 mm3) tumors was not statistically significant (P greater than 0.1). Our results may explain the size-dependent enhancement in pO2 and radiation response reported by I. Lee and C. W. Song (Radiat. Res., 130: 65-71, 1992) for this tumor line. If our results could be confirmed in human tumors in situ, they would have significant implications in noninvasive measurements of TIFP using NMR and in cancer treatment using radiation, chemotherapy, and immunotherapy.

2H-nuclear magnetic resonance imaging of tumor blood flow: spatial and temporal heterogeneity in a tissue-isolated mammary adenocarcinoma.

Abstract: 2H-Nuclear magnetic resonance imaging of deuteron accumulation in tissue following an iv 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 was tested in rat brain and then applied to the study of spatial heterogeneity and temporal variation of blood flow in the tissue-isolated R3230AC mammary adenocarcinoma Global flow from the brain averaged 096 ml/min-g, in good agreement with results obtained from other methods; the perfusion of brain was relatively homogeneous Global tumor blood flow averaged 032 ml/min·g, ranging from 011 to 096 ml/min·g Imaging revealed variations in perfusion both within and between the tumors that far exceeded those expected from brain flow heterogeneity and uncertainty in the flow estimates By obtaining repeated flow images at 30-min intervals, it was possible to show that the regional blood flow shifted with time in single pixels and in multipixel regions These experiments show that 2H-nuclear magnetic resonance may be useful in obtaining noninvasive and quantitative measurement of temporal blood flow changes in a solid tumor in vivo

Pharmacokinetic analysis of the perivascular distribution of bifunctional antibodies and haptens: comparison with experimental data.

Abstract: A mathematical model is developed to describe the concentration profiles around individual tumor blood vessels for two-step approaches to cancer treatment. The model incorporates plasma pharmacokinetics, interstitial diffusion, reversible binding between antibody and hapten and between antibody and tumor-associated antigens, and physiological parameters to evaluate present experimental approaches and to suggest new guidelines for the effective use of two-step approaches. Results show considerable interaction between the binding kinetics, initial drug doses, and antigen density, with optimal parameter ranges depending on the desired goal: treatment or detection. The hapten concentration in tumors was found to be nonuniform because of specific binding to antibodies. While binding of the hapten to the bifunctional antibody is necessary for improved retention, too large a binding affinity may lead to very poor penetration of the hapten into regions far away from blood vessels. The time delay between antibody and hapten injection was found to be an important parameter. Longer time delays were found to be advantageous, subject to constraints such as internalization of the antibody and tumor growth during treatment. A proper combination of initial doses for the two species was also seen to be crucial for maximum effectiveness. Comparison of the model with the experimental data of Le Doussal et al. (Cancer Res., 51: 6650-6655, 1991) and Stickney et al. (Cancer Res., 50: 3445-3452, 1990) suggests two novel, yet testable, hypotheses: (a) the early pharmacokinetics of low molecular weight agents can have an important effect on later concentrations using two-step approaches; and (b) metabolism may play an important role in reducing concentrations in the tumor and tumor:plasma concentration ratios. These results should help in the effective design of two-step strategies.

CT diagnosis of macrodystrophia lipomatosa. A case report.

Abstract: Radiographs and CT scans of a 45-year-old male with progressive enlargement of his right upper limb and shoulder are presented. Extensive soft-tissue hypertrophy with linear radiolucent bands (fat) limited to the lateral aspect of the limb were seen. Exostoses-like bony overgrowths were also seen along interphalangeal joints. At CT, hypertrophic adipose tissue intermingling with muscle fibers was demonstrated, a diagnostic finding distinguishing the lesion from plexiform neurofibrolipomatosis, Klippel-Trenaunay syndrome and other angiomatous lesions.

Kinetics of interleukin-2 induced changes in rigidity of human natural killer cells.

Abstract: The success of adoptive immunotherapy is dependent in part on the successful delivery of effector cells to the tumor and the expression of cellular activities, such as adhesion, extravasation, and cytotoxic activity of the effector cells in the tumor. The structural rigidity of the effector cell is an important determinant of these functions. The present study was designed to quantify the changes in cellular rigidity and cytotoxic activity of human natural killer (NK) cells in the presence or absence of interleukin-2 (IL-2). Micropipet aspiration was used to measure the resistance of NK cells to an imposed external deformation. Homogeneous suspensions of NK cells were activated with 1000 U/mL of recombinant IL-2 in vitro and tested for cellular rigidity from 0 to 96 h post stimulation. The IL-2 activated cells increased their rigidity within 24 h and maintained it at this level for 96 h. Prolonged incubation of cells in IL-2 (14 d) resulted in a consistently high rigidity, which was further increased on starvation of the cells from IL-2. The increased rigidity of these cells was maintained throughout 96 h of IL-2 deprivation, although significant relaxation of rigidity was observed between 48 and 96 h. The relaxation of rigidity was associated with an increase in the number of nonviable cells. Reintroduction of IL-2 for 24 h to a culture of NK cells depleted of IL-2 for 48 h did not restore the cells to the predepletion level of rigidity. Cytotoxic activity of the activated NK cells following removal of IL-2 decreased to about 60% of the control activity within 24 h and continued through 72 h postdeprivation. These findings suggest that the initial activation of human NK cells by IL-2 will produce a relatively rapid increase in rigidity that may cause entrapment of these cells in small capillaries in vivo and that removal of IL-2 will produce an additional increase in rigidity, which is associated with decreased functional activity.

Microvascular network architecture in a mammary carcinoma

Abstract: The distribution of blood flow in a given tumor regulates the exchange and uptake of relevant molecules in chemo-, immuno-, and radiation therapy, thereby determining the efficacy of present day cancer treatments. Because it plays a significant role in heat transfer, the distribution of blood flow is also important in both thermographic detection and hyperthermia treatment [1, 2]. But what determines the distribution of blood flow in a microvascular network? In both normal and pathologic tissues, blood flow through a vascular bed is determined by several factors including the vascular network topology and the dimensions of the blood vessels. Previous workers have made qualitative comparisons of host and tumor vasculature including both animal tumors (for review see [3]) as well as human tumor xenotransplants [4]. To date, however, there exists no quantitative data describing the microvascular network architecture of any tumor type. If such data can be obtained, then a network model capable of predicting the blood pressure and flow distribution in a given tumor can be constructed, thus allowing insight into growth rate variability among tumors and the mechanisms governing current cancer therapies. Below is a brief presentation of the results of such a quantitative analysis of the vascular network topology in a mammary adenocarcinoma from Less et al. [5].

Use of synthetic H disaccharides as acceptors for detecting activities of UDP-GalNAc:Fuc alpha 1-->2Gal beta-R alpha 1-->3-N-acetylgalactosaminyltransferase in plasma samples from blood group A subgroups.

Abstract: Concentrations of blood group A-specified alpha(1-->3)-N-acetylgalactosaminyltransferase (A enzyme) were measured in human plasma of blood groups A1, A2, and A3 by using chemically synthesized H disaccharides and H type 1 and type 2 trisaccharides attached to hydrophobic aglycones as acceptors. When the trisaccharides were used as acceptors, enzyme activities were reduced in samples from A2 and A3. However, the H disaccharides were shown to be good acceptors even for enzymes from A2 and A3, and no significant difference in enzyme concentration was detected in any of the plasma tested.

CT Diagnosis of Macrodystrophia Lipomatosa

Abstract: Radiographs and CT scans of a 45-year-old male with progressive enlargement of his right upper limb and shoulder are presented. Extensive soft-tissue hypertrophy with linear radiolucent bands (fat) limited to the lateral aspect of the limb were seen. Exostoses-like bony overgrowths were also seen along interphalangeal joints. At CT, hypertrophic adipose tissue intermingling with muscle fibers was demonstrated, a diagnostic finding distinguishing the lesion from plexiform neurofibrolipomatosis, Klippel-Trenaunay syndrome and other angiomatous lesions.

Pedunculated focal nodular hyperplasia.

Abstract: A 12-year-old female was admitted to the Cardiothoracic Surgery Unit for surgical correction of tetrology of Fallot. On routine preoperative examination a large, firm, freely mobile intra-abdominal mass was detected, of which the patient was unaware, An abdominal US revealed a large, welldefined, lobulated mass of heterogenous echogenicity, with central hypoechoic branching linear areas and a small speck of calcification. The mass was continuous with the inferior edge of medial segment of left lobe of liver through a narrow pedicle, with no surrounding liver parenchyma. The pedicle contained dilated vascular channels (Fig. 1). Color Doppler examination revealed these vascular channels to be a branch of left hepatic artery, and a vein draining directly into the left hepatic vein. These vessels could be traced into the centre of the mass, from where branches radiating to the periphery of the mass could be seen. Rest of the hepatic parenchyma and other intra-abdominal organs were normal. Contrast enhanced CT scan of the abdomen revealed a large well-defined, lobulated, enhancing mass with centralhypodense branching areas containing enhancing blood vessels and calcification (Fig. 2). Communication between the inferior edge of the left lobe of liver and mass through a pedicle containing dilated tortuous vascular channels could be made out. On the basis of these radiological findings a diagnosis of pedunculated liver tumor was made. Further, characteristic features, viz; a central branching area (scar) containing blood vessels and calcification, helped us make a diagnosis ofpedunculated focal nodular hyperplasia (FNH). All radiological findings were confirmed at surgery the pedicle was ligated and the mass excised in-toto. Histopathology was confirmatory for FNH. Interestingly, after excision of the mass, an appreciable decrease was noted in the degree of the patient's cyanosis. F N H is classically descr ibed in middleaged females and is usual ly asymptomatic. The mass is usual ly small (average 4 cm d iameter ; m a x i m u m repor ted size 20 cm). A cent ra l scar con ta in ing f ibrous tissue, vascular channels and calcificat ion is of ten p resen t (60 % ) and is pat h o g n o m o n i c [1]. Sonography is sensi t ive for de tec t ion of F N H , bu t the echo-pa t t e rn of these tumors is var iable and non-specif ic thus d i f ferent ia t ion with o the r b e n i g n and ma l ignan t l iver tumors is no t possible on the basis of US a lone [1]. Our exper ience suggests that a c o m b i n a t i o n of Color D o p p l e r and 2D US imaging can help m a k e a specific diagnosis by demons t r a t ing the characteris t ic pa t t e rn of vascular supply, with ma jo r feeder b lood vessels and their b ranches con ta ined within the centra l hypoechoic scar. C T appea rances of F N H are non-specific with a var iable a t t enua t ion pa t t e rn on both non -con t r a s t and contras t enhanced scans, though a hypodense les ion on precont ras t scan which becomes