Tissue Cylinder Research Articles

Gene expression variation between distinct areas of breast cancer measured from paraffin-embedded tissue cores

BackgroundDiagnosis and prognosis in breast cancer are mainly based on histology and immunohistochemistry of formalin-fixed, paraffin-embedded (FFPE) material. Recently, gene expression analysis was shown to elucidate the biological variance between tumors and molecular markers were identified that led to new classification systems that provided better prognostic and predictive parameters. Archived FFPE samples represent an ideal source of tissue for translational research, as millions of tissue blocks exist from routine diagnostics and from clinical studies. These should be exploited to provide clinicians with more accurate prognostic and predictive information. Unfortunately, RNA derived from FFPE material is partially degraded and chemically modified and reliable gene expression measurement has only become successful after implementing novel and optimized procedures for RNA isolation, demodification and detection.MethodsIn this study we used tissue cylinders as known from the construction of tissue microarrays. RNA was isolated with a robust protocol recently developed for RNA derived from FFPE material. Gene expression was measured by quantitative reverse transcription PCR.ResultsSixteen tissue blocks from 7 patients diagnosed with multiple histological subtypes of breast cancer were available for this study. After verification of appropriate localization, sufficient RNA yield and quality, 30 tissue cores were available for gene expression measurement on TaqMan® Low Density Arrays (16 invasive ductal carcinoma (IDC), 8 ductal carcinoma in situ (DCIS) and 6 normal tissue), and 14 tissue cores were lost. Gene expression values were used to calculate scores representing the proliferation status (PRO), the estrogen receptor status and the HER2 status. The PRO scores measured from entire sections were similar to PRO scores determined from IDC tissue cores. Scores determined from normal tissue cores consistently revealed lower PRO scores than cores derived from IDC or DCIS of the same block or from different blocks of the same patient.ConclusionWe have developed optimized protocols for RNA isolation from histologically distinct areas. RNA prepared from FFPE tissue cores is suitable for gene expression measurement by quantitative PCR. Distinct molecular scores could be determined from different cores of the same tumor specimen.

Theoretical Models of Microvascular Oxygen Transport to Tissue

To improve understanding of microvascular O(2) transport, theoretical modeling has been pursued for many years. The large number of studies in this area attests to the complexities (i.e., biochemical, structural, and hemodynamic) involved. This article focuses on theoretical studies from the last two decades and, in particular, on models of O(2) transport to tissue by discrete microvessels. A brief discussion of intravascular O(2) transport is first given, highlighting the physiological importance of intravascular resistance to blood-tissue O(2) transfer. This is followed by a description of the Krogh tissue cylinder model of O(2) transport by a single capillary, which is shown to remain relevant in modified forms that relax many of the original biophysical assumptions. However, there are many geometric and hemodynamic complexities that require the consideration of microvascular arrays and networks. Multivessel models are discussed that have shown the physiological importance of heterogeneities in vessel spacing, O(2) supply, red blood cell flow path, as well as interactions between capillaries and arterioles. These realistic models require sophisticated methods for solving the governing partial differential equations, and a range of solution techniques are described. Finally, the issue of experimental validation of microvascular O(2) delivery models is discussed, and new directions in O(2) transport modeling are outlined.

Endocervical Coring at Laparoscopic Supracervical Hysterectomy Removes a Majority of Endocervical Glands

Study Objective: Endocervical coring during hysterectomy, a previously described technique, removes a central cylinder of tissue from the cervix. While this maneuver may have other benefits, removing this tissue may reduce cyclic vaginal bleeding and subsequent development of cervical neoplasia. In this pilot study we aimed to evaluate the amount and type of tissue removed during endocervical coring at laparoscopic supracervical hysterectomy with transcervical morcellation (LSH/TCM). Removal of all or a majority of active endocervical tissue would provide pathologic evidence in support of the safety and efficacy of supracervical hysterectomy.

MO-E-AUD B-01: Distribution of Secondary Particles In Carbon Ion Therapy

Purpose: The purposes of this work was to study the spallation product generation from a 355.91 MeV/nucleon carbon beam impinged onto a cylinder of Tissue Equivalent Plastic, and analyze its spectra as a function of energy distribution and distance using a three‐dimensional Monte Carlo particle transport code. Method and Materials: Simulations were performed using a 350 MeV/nucleon carbonion beam incident on a test phantom. The geometry for the test phantom was a cylinder with 20 cm height and 10 cm radius comprised of Tissue Equivalent Plastic. An energy of 350 MeV/nucleon was selected because it is in the range frequently used in carbon ion therapy. Monte Carlo analyses for spallation production were done using HETC‐HEDS. Results: A total of 23.74 % of the original beam was fragmented into charged particles between charges 1 and 5. Almost all charged fragments deposit their energies locally within the cylinder, and nothing escapes from the system.. Compared to neutrons and protons,charged particle fragment production is much lower as the percentages were 473.28 % and 295 % for neutrons and protons, respectively. For protons, most particles will exit the target following the direction of the primary beam. For the neutrons case, however, the 473.28 % exit the target in all directions make it very difficult to conclude that their direction is random. Conclusion: Secondary particle production is alarming especially for neutrons produced. Those secondary particles have a wide range of energy and are certainly able to cause secondary tumors. For the charged particles heavier than protons, almost 24% of the primary beam is produced as particles that range from charges 1 through 5. For the neutrons and the protons, the fluences were 473% and 293%. Those particles have high quality factors and could travel enough distance to cause DNA damage in healthy tissue.

Detachment of Listeria innocua and Pantoea agglomerans from cylinders of agar and potato tissue under conditions of Couette flow

Cylinders of raw potato or agar were contacted with suspensions of Listeria innocua and Pantoea agglomerans and then used as replacement rotors in a rheometer in order to investigate detachment under the influence of known shear forces. These shear forces were functions solely of the rotational speed of the rotor and the fluid (glycerol) in which the cylinders were caused to rotate. With this system surface shear forces ranging from 1.3 to 125 Pa could be generated corresponding to rotational speeds of 12.5–775 rpm. Under these conditions detachment phenomena were quite rapid with in most cases complete detachment being achieved over timescales of the order of 30 s. In general, lower shear forces were required to detach L. innocua from both agar and potato. For agar cylinders an applied shear force of only 1.3 Pa was sufficient to achieve 98% detachment of L. innocua after 20 s. By contrast, relatively high shear forces were required to detach P. agglomerans particularly from potato; under an applied shear force of 2.8 Pa only 9.5% detachment was achieved after 30 s. The results obtained at the highest shear forces studied here (125 Pa) with potato cylinders were suggestive of mass transfer into glycerol of one or more constituents present in potatoes that caused detached cells to aggregate causing an apparent decrease in percentage detachment. The data obtained could be used as a basis for the rational design of washing processes for fresh ready to eat food products.

Clinical value of endoscopic ultrasound-guided transesophageal fine needle puncture of mediastinal lesions

As the mediastinum has been a region difficult to access for biopsy, mediastinoscopy has been required in most cases. In a prospective study the value of transoesophageal endoscopic ultrasound (TEUS) guided aspiration biopsy was assessed as an alternative. TEUS-guided fine-needle aspirations were performed between May 1995 and March 1998 in 35 patients with mediastinal space-occupying lesions. In all cases the conventional endoscopic method or percutaneous puncture-sonography had been impossible or had failed. In one patient it had been performed after a negative mediastinoscopy. In 34 patients (97%) the aspirated tissue cylinder could be evaluated histologically. There were no complications. Malignancy was demonstrated in 24 patients, and there were one case each of sarcoidosis, silicoanthracosis and two cases of retrosternal goitre. In four of seven patients the negative preoperative diagnosis was confirmed at operation or by follow-up. There were two false-negative results and in one patient there has been no definitive diagnosis. The accuracy of the method was thus 91.4%, the positive predictive value for malignancy 88.9% and the negative predictive value for malignancy 72.7%. Ultrasound alone was a poor predictor of malignancy in lymph node enlargement. TEUS-guided fine-needle aspiration of space-occupying mediastinal lesions is an effective and low-risk method that can in selected cases shorten the diagnostic process and avoid methods that are expensive or lead to complications such as transpulmonary biopsy guided by computed tomography or mediastinoscopy.

Ultrasound-guided thin-needle biopsy in focal liver diseases. I. Malignant hepatic tumors

Eighty-six patients with focal liver disease underwent sonography-guided percutaneous fine needle biopsy for definitive diagnosis. Twenty-five out of twenty-six neoplastic liver tumors were correctly recognized as malignant. A sensitivity of 96% and a specificity of 98% (25 true positives, 60 true negatives, 1 false negative) was obtained. The high accuracy rate of this diagnostic procedure is explained by the precision of sonographic guidance and the copious excision of tissue material. In 57% of the malignant tumors, small tissue cylinders were obtained besides cytological material, which allowed a definitive tumor diagnosis in 11 out of 15 cases by histologic examination. In addition, the histologic evaluation of tissue fragments enables the differentation between primary and secondary hepatic malignomas. Because of the higher specificity of histological diagnosis, fine needle puncture of solid liver tumors should always provide tiny tissue cylinders for histologic examination.

Ultraschallgeführte Feinnadelbiopsie herdförmiger Lebererkrankungen - Teil II: Benigne herdförmige Lebererkrankungen

Sixty patients with benign focal liver disease underwent sonography-guided percutaneous fine needle biopsy for definitive diagnosis. The benignancy of all lesions was determined accurately by cytohistologic evaluation. All 44 liquid space-occupying lesions (30 hepatic cysts, 9 abscesses, 3 hematomas, 2 serous residual cavities after surgery) could be classified by cytological, biochemical and bacterial examination. The diagnosis of hepatic hemangiomas by fine needle puncture is problematic, because the cytological identification of benign endothelial cells is difficult. The histological examination of tissue cylinders of 4 small echogenic lesions revealed focal fatty change of the liver. Tissue fragments of focal nodular hyperplasias and liver cell adenomas showed histologically typical liver cells arranged in trabecular structure. The additional identification of bile ducts supplies proof of focal nodular hyperplasia and excludes liver cell adenoma. Percutaneous puncture of liver abscesses and cysts afforded effective therapeutic decompression. Eight out of 9 liver abscesses were cured by evacuating fine needle puncture. More than 50% of the liver cysts showed long-term growth shrinkage subsequent to puncture. The histological confirmation of benign and malignant liver tumors by sonographyguided fine needle biopsy is considered a decisive step forward in the diagnostic possibilities of update imaging methods.

Analytic Solution to Steady-State Radial Diffusion of a Substrate with First-Order Reaction Kinetics in the Tissue of a Krogh's Cylinder

It is often useful to calculate the concentration profile for a substrate undergoing reaction in the tissue surrounding a capillary. In this paper, we consider a model geometry consisting of a long straight cylinder of tissue surrounding a capillary. Substrate diffuses radially out of the capillary through the tissue, with consumption of substrate in the tissue directly proportional to substrate concentration (i.e., first-order reaction kinetics). The model is extended to include the case where a cylinder of necrotic tissue surrounds a metabolically active inner tissue cylinder. A simple analytic solution is derived, and concentration profiles are generated for various combinations of parameters. Compared to the case where substrate consumption is independent of concentration, this model predicts much more rapid depletion of substrate near the capillary interface. This can have significant implications for the calculation of the hypoxic fraction (e.g., tissue with pO(2)<0.5-5 mmHg) when tumor oxygenation is modeled. The model also permits calculation of the limiting substrate concentration for cell viability when the reaction rate constant is known and vice versa.

Microstructural changes during osmotic dehydration of parenchymatic pumpkin tissue

Pumpkin ( Cucurbita pepo L.) fruit was selected to study the microstructural changes of vegetable tissue during osmotic dehydration. Cylinders (diameter: 1.5 cm; length 2.5 cm) of the parenchymatic tissue were dehydrated with 45% (w/w) sucrose solutions at 25 °C. The microstructure of fresh and processed samples was observed using light microscopy techniques. Fresh pumpkin cells showed average values of 0.015 mm 2, 0.469 mm and 0.136 mm for cell area, cell perimeter and cell equivalent diameter, respectively; and 1.288, 0.831 and 0.871 for cellular elongation, roundness and compactness, respectively. The main modifications observed during osmotic dehydration were shrinkage of cells, plasmolysis and folding of the cell walls. These changes led to the decrease of cellular area, equivalent diameter, roundness and compactness; elongation of cells increased whereas the perimeter was maintained essentially constant along the process. The observed changes were not homogeneously distributed in the material, and were dependent on cell location in the sample and on process time. Empirical quadratic functions were used to relate the average cellular shape and size parameters with the dehydration parameters water loss, weight reduction and normalized moisture content. The equations showed a good fit of the experimental data, leading to correlation coefficients ranging 0.93–0.99 and average relative deviations ranging 0.7–2.8%.

Hemoglobin-Based O2 Carrier O2 Affinity and Capillary Inlet pO2 Are Important Factors That Influence O2 Transport in a Capillary

Hemopure (Biopure; Cambridge, MA) and PolyHeme (Northfield Laboratories; Evanston, IL) are two acellular hemoglobin-based O2 carriers (HBOCs) currently in phase III clinical trials for use as red blood cell substitutes. The most common adverse side effect that these HBOCs exhibit is increased vasoconstriction. Autoregulatory theory has been presented as a possible explanation for this physiological effect, where it is hypothesized that low-affinity HBOCs over-deliver O2 to tissues surrounding arterioles, thereby eliciting vasoconstriction. In this paper, we wanted to investigate HBOC oxygenation of tissue surrounding a capillary, which is the smallest element of the circulatory system. An a priori model has been developed in which the performance of mixtures of acellular HBOCs (synthesized by our group and others) and human red blood cells (hRBCs) has been simulated using a Krogh tissue cylinder model (KTCM) comprising a capillary surrounded by a capillary membrane and skeletal muscle tissue in cylindrical coordinates with specified tissue O2 consumption rates and Michaelis-Menten kinetics. In this study, the total hemoglobin (hRBCs and HBOCs) concentration was kept constant. The HBOCs studied possessed O2 affinities that were higher and lower compared to hRBCs (P50's spanned 5-55 mmHg), and the equilibrium binding/release of oxygen to/from the HBOCs was modeled using the Adair equation. At normoxic inlet pO2's, there was no correlation between O2 flux out of the capillary and the O2 affinity of the HBOC. However, a correlation was found between the average pO2 tension in the capillary and the O2 affinity of the HBOC. Additionally, we studied the change in the O2 equilibrium curve of HBOCs with different O2 affinities over a wide range of inlet pO2's and found that changing the inlet pO2 greatly affected which HBOC, having a unique O2 affinity, best delivered O2 to the surrounding tissue. The analysis of oxygen transport presented could lead to a better prediction of which acellular HBOC is best suited for a specific transfusion application that many times depends on the capillary inlet pO2 tension.

Glypican-3 Expression in Primary and Recurrent Ovarian Carcinomas

The identification of glypican-3 (GPC3) expression in malignant neoplasms is potentially of interest because GPC3 might represent a therapeutic target. Tissue microarrays containing tissue cylinders from 308 patients with ovarian carcinomas were used for an immunohistochemical study. There were 255 serous, 38 endometrioid, and 15 clear-cell carcinomas included. From 76 patients, paired tissue samples of primary serous ovarian carcinomas and their corresponding recurrences after platinum-based chemotherapy were available. Glypican-3 was expressed in a total of 17.9% of ovarian carcinomas and was strongly associated with the clear-cell histotype (P = 0.0001). Glypican-3 expression was not associated with tumor stage. Positive staining for GPC3 was also observed in a significant fraction of recurrent carcinomas but was not particularly associated with chemoresponse. In conclusion, our data show that GPC3 is observed in a significant fraction of primary and corresponding recurrent ovarian carcinomas. Glypican-3 may therefore represent a potential target for (second-line) therapy in ovarian cancer.

ICon-TMA ® for control and quantitation of immunohistochemistry and in situ molecular pathology analysis

Reliable assessment of in situ pathology analyses like immunohistochemistry, RNA in situ hybridization, and FISH are critically important in diagnosis and treatment decisions. We describe the development of small tissue microarrays (TMA) for the internal control and quantitation of these techniques, the iCon-TMA ®. In its simple variant, these iCon-TMA ® (abbreviated from internal control TMA) consist of 2 tissue cylinders, one being clearly positive and the other clearly negative for a specific marker. In its more elaborate format, the iCon-TMAs ® carry additional tissue spots providing a scale for quantitatively assessable markers, e.g. representing scores of negative, weak, moderate, or strong positivity. The specimen with the yet unknown reactivity is then applied to the iCon-TMA ® section, and both are simultaneously processed and analyzed, thus providing a convenient measure for in situ quality control and quantitation.

TU‐EE‐A4‐01: Dose Saving and Scatter Reduction in Volume‐Of‐Interest (VOI) Cone Beam CT — a Monte Carlo Simulation Study with Geant4

Purpose: To estimate and study the dose saving and scatter reduction properties of the VOI cone beam CT technique. Method and Materials: To implement the VOI scanning technique, a filter with a circular or rectangular opening is inserted between the x‐ray source and the patient to deliver a higher level x‐ray exposure inside the VOI and a lower exposure level outside the VOI in acquiring the projection images. This technique is expected to result in higher image quality inside the VOI with lower entire patient dose and significantly lowered scatter‐to‐primary ratios (SPRs) within the VOI. Modeling the patient as a cylinder of soft tissue, we have developed Monte Carlo simulation programs based on the Geant4 package to estimate the dose to the patient and the SPRs at the detector input. Simulation was performed at selected locations to estimate the variation of the dose level and SPRs from inside to the outside of the VOI. Simulation was also performed to estimate the reduction of the dose levels and SPRs with the VOI scanning technique as compared to full field cone beam CT. Results: Our simulation results show that with the exposure level reduced by the VOI filter, dose levels for the entire scan were significantly reduced both inside and outside the VOI. Scatter intensities at the detector input were also shown to decrease significantly both inside and outside the VOI in the projection images. Conclusion: Our simulation study successively demonstrated the ability of the VOI scanning technique to reduce patient dose and x‐ray scatter for improved image quality. Acknowledgement: This work was supported in part by a research grant EB000117 from the NIH‐NIBIB and a research grant CA104759 from the NIH‐NCI. The author also would like to thank Dr. Ioannis Sechopoulos and Yu Chen for consulting assistance in Geant4 programming.

The Role of EUS Elastography in the Diagnosis of Focal Liver Lesions

Sonoelastography is a new ultrasound procedure for the assessment of tissue elasticity, with a very good potential of implementation in the field of endoscopic ultrasogography. The reconstruction of tissue elasticity provides important information about the nature of the disease. The elasticity of the tissue is evaluated qualitatively on the standard B mode with color image in the range from red to blue. The more hard tissues are presenting in blue and easily compressible tissues in red. Giovannini suggest that EUS elastography could be a good diagnostic tool in defining the tissue characteristics of benign and malignant lesions. Case Report: 25-year-old woman presented at our Unit with a two-month history of fever of unknown origin, night sweats and mild abdominal pain. Her previous medical history was unremarkable. On physical examination, only abnormal finding was enlarged liver palpable 3 cm below the right costal margin. Laboratory results showed slightly elevated liver enzymes. Synthetic liver function was normal. Excluded were all potential bacterial and virological causes, hereditary and acquired metabolic liver diseases and autoimmune liver diseases. Chest X-ray was normal. Abdominal ultrasound (US) detected several hipoechogenic lesions, two in left liver lobe (26 and 29 mm) and several smaller in right liver lobe (up to 8 mm in size). This was confirmed with contrast-enhanced multislice computed tomography (MSCT) which showed multiple hypoattenuated lesions on native images which were hypovascular on postcontrast images with no signs of abnormal intrahepatic vascularisation EUS elastography showed diffuse “blue” pattern in the left liver lobe, indicating hard elasticity in the area of focal lessions and in the surrounding tissue. It was therefore concluded that we were dealing with a diffuse liver disease. Liver biopsy of the left liver lobe was performed with US guidance. Tissue cylinder contained the tissue surrounding the focal lesion and part of the focal lesion itself. Histological analysis revealed diffuse granulomatosus infiltration of the liver. Differential diagnosis of hepatic granulomatous disease is very broad, two major causes being sarcoidosis and tuberculosis. . EUS elastography, histology and slightly elevated serum angiotensin converting enzyme (ACE) of 62 U/L (normal up to 52 U/L) pointed toward the diagnosis of liver sarcoidosis. We suggest that EUS elastography is a promising diagnostic method that allows differentiation of the focal liver lesions from the normal liver tissue and detection of diffuse liver disease, with a great diagnostic potential in difficult cases like the one described.

Cascadiacarpa spinosa gen. et sp. nov. (Fagaceae): castaneoid fruits from the Eocene of Vancouver Island, Canada

Documenting the paleodiversity of well-studied angiosperm families serves to broaden their circumscription while also providing a time-specific reference point to mark the first occurrence of characters and appearance of lineages. More than 80 anatomically preserved specimens of spiny, cupulate fruits in various developmental stages have been studied from the Eocene Appian Way locality of Vancouver Island, British Columbia, Canada. Details of internal anatomy and external morphology are known for the cupules, fruits, and pedicels. Cupule spines branch and are often borne in clusters. Cupules lack clear sutures and are adnate to a single nut that is enclosed entirely with the exception of the apical stylar protrusion of the pistil. A central hollow cylinder of vascular tissue can be seen extending up the peduncle to the base of the fruit and along the inner wall of the cupule. The fruit has a sclerotic outer pericarp that grades into a parenchymatous mesocarp and a sclerotic endocarp lining the locules. Early in development, the two locules are divided by a thin septum to which the ovules are attached. Only one seed develops to maturity as evidenced by an embryo occupying the locule alongside an abortive apical ovule. Three-dimensional reconstructions of these fruits have allowed for comparisons to both extinct and extant fagaceous taxa. The Appian Way fruits are most similar to extant Castanopsis species (Fagaceae) but differ in having only two locules. Cascadiacarpa spinosa gen. et sp. nov. Mindell, Stockey et Beard is the first occurence of a bipartite gynoecium and earliest known occurrence of hypogeous fruits in Fagaceae. The appearance of Casacadiacarpa in the Eocene of British Columbia supports a Paleogene radiation of the family. The numerous derived characters of these fruits show that evalvate, spiny, single-fruited cupules of Fagaceae were present in the Paleogene of North America.

Relation between mechanical properties and structural changes during osmotic dehydration of pumpkin

This work presents the changes in the mechanical properties of pumpkin (Cucurbita pepo L.) fruits when submitted to osmotic dehydration processes. Cylinders of the parenchymatic tissue were dehydrated with sucrose solutions, varying the concentration (30–60% w/w) and temperature (12–38 C) of the osmotic solution and process time (0–9 h). As an opposite process to dehydration, water soaking of some cylinders was also performed. Samples were submitted to uniaxial compression until rupture, and four parameters were analyzed: apparent modulus of elasticity, true stress at failure, Hencky strain at failure and failure work (toughness). Values of these mechanical properties for fresh material ranged from 0.96 to 2.53 MPa for apparent modulus of elasticity, 250–630 kPa for failure stress, 0.42– 0.71 for failure strain and 85–285 kJ/m 3 for toughness. Mechanical properties of osmodehydrated samples showed no dependence on concentration of the osmotic solution and process temperature, whereas they were found to be dependent on moisture content: apparent elastic modulus decreased and failure strain increased during dehydration; toughness and failure stress initially decreased with moisture content, and increased at advanced stages of the process. Water soaked samples showed a decrease in failure strain, failure stress and toughness, but the apparent elastic modulus increased. Simultaneous structural observation during compression showed that the material fails in the contact zones of its fibres. This fact and the observed structural profiles during dehydration could explain the changes in the failure properties (strain, stress, toughness) along the studied processes. Changes in the apparent modulus of elasticity were likely related with the changes in the turgor pressure of cells. 2007 Elsevier Ltd. All rights reserved.

Calculated signal-to-noise ratio of MRI detected with SQUIDs and Faraday detectors in fields from 10 μT to 1.5 T

We examine the calculated signal-to-noise ratio (SNR) achievable with different MRI detection modalities in precession fields ranging from 10 μT to 1.5 T. In particular, we compare traditional Faraday detectors with both tuned and untuned detectors based on superconducting quantum interference devices (SQUIDs). We derive general expressions for the magnetic field noise due to the samples and the detectors, and then calculate the SNR achievable for a specific geometry with each modality with and without prepolarization. We show that each of the three modalities is superior in one of the three field ranges. SQUID-based detection is superior to conventional Faraday detection for MRI in precession fields below 250 mT for a 65 mm diameter surface coil placed a distance of 25 mm from the voxel of interest embedded in a cylinder of tissue 50 mm tall and of radius 50 mm. This crossover field, however, is sensitive to the geometry.

Model of human skin oxygenation under thermal actions

The problem of diffusion transfer of oxygen from an individual capillary into the surrounding skin with regard for the inhomogeneity of the blood composition in the vessel (plasma and erythrocytes) has been solved. The approximate dependence of the average concentration of oxygen in the tissue cylinder on its radius (density of active capillaries) and the circulation rate has been obtained. The model has been generalized to the macromolecule of a biotissue segment with a multitude of exchange vessels, and the dependence of the average concentration of oxygen in the biotissue bulk on the blood flow intensity (perfusion) has been obtained.

Construção de arrays de tecido com equipamento alternativo e de baixo custo para estudo imuno-histoquímico de tumores mamários

INTRODUÇÃO: Tissue microarrays (TMA) são blocos contendo numerosos cilindros de tecido parafinado organizados em linhas e colunas que permitem analisar muitas amostras numa única lâmina. Equipamentos disponíveis comercialmente são importados e têm alto custo (entre 11 e 24 mil dólares). OBJETIVOS: Descrever uma forma alternativa de construção de arrays de tumores mamários de baixo custo e relatar nossa experiência na sua utilização em estudo imuno-histoquímico (IIQ). METODOLOGIA: Utilizou-se modelo que consiste numa minirretífica com agulha de biópsia hepática de 2mm de diâmetro acoplada à bancada com suporte (Dremel). Inicialmente preparou-se o bloco receptor fazendo o número de furos desejável (55). Cilindros de tecido foram obtidos com o mesmo dispositivo e colocados nos orifícios do bloco receptor. De cada bloco doador, obteve-se dois cilindros de diferentes áreas representativas do tumor. Em cada array foram incluídos cilindros de tumor (controle positivo e negativo) para cada anticorpo testado na IIQ, e cilindro marcador de iniciação da leitura da lâmina (fígado). Cortes seqüenciais de 4µm obtidos do array foram submetidos à IIQ. A primeira e a última lâmina foram coradas pela hematoxilina e eosina (HE) para avaliar: número de discos de tecido, preservação tecidual e adequabilidade da amostra. Foi realizada IIQ empregando anticorpos anti-receptores de estrógeno, progesterona, Ki67, p53 e Her2. RESULTADOS: O custo total do equipamento foi apenas US$180,00. Cortes histológicos do array apresentaram boa preservação tecidual, sendo adequados para avaliação morfológica e suficientes para confirmação diagnóstica. A qualidade das reações IIQ foi semelhante à obtida nos blocos doadores. CONCLUSÃO: Esse equipamento e a técnica representam uma alternativa econômica aos equipamentos comerciais.