Importance of the lung perfusion scintigraphy in single lung transplantation.

Lung perfusion scintigraphy (LPS) with (99m)Tc-MAA gives valuable information about patients who will undergo a single lung transplantation. This technique makes it possible to evaluate and quantify the relative function of both lungs to select the organ to be transplanted. Once the surgery has been performed, the LPS represents a diagnostic method to study the status of the transplanted organ. Two patients who underwent single lung transplantation were studied in our hospital. In both cases, a pre-operative LPS was performed before surgery for selection of the organ to be transplanted and the scintigraphy study was performed a few months after transplantation to establish the perfusion function of the transplanted lung.

(99m)Tc-labeled murine ior C5 monoclonal antibody in colorectal carcinoma patients: pharmacokinetics, biodistribution, absorbed radiation doses to normal organs and tissues and tumor localization.

Monoclonal Antibody (mAb) ior C5 is a murine IgG(1) that recognizes the tumor associated antigen (TAA) ior C2, a cell surface O-linked glycoprotein carbohydrate chain not present in most normal tissues and homogeneously expressed in the cytoplasm of normal colon epithelium and heterogeneously expressed in more than 83% of primary colorectal carcinomas. This study was designed to investigate the pharmacokinetics, biodistribution and the absorbed radiation doses of (99m)Tc-labeled mAb ior C5 antibody in colorectal tumor patients. Ten patients were administered 3 mg of anti-O-linked glycoprotein carbohydrate chain TAA ior C2 murine monoclonal antibody ior C5 radiolabeled with (99m)Tc activity of 1435.0 +/- 123 MBq by intravenous (i.v.) bolus infusion. Blood and urine samples were collected from 4 out of 10 patients at timed intervals from 10 min and up to 24 h after injection of the (99m)Tc-labeled mAb ior C5 for pharmacokinetic studies. Whole body images were taken in 5 out of 10 patients for quantitative normal organ biodistribution and dosimetry studies and planar anterior and posterior and SPECT images were taken in 5 out of 10 patients for tumor localization. Mean absorbed doses were estimated using the methods developed by the Medical Internal Radiation Dose (MIRD) committee. The effective dose equivalent (EDE) and effective dose (ED) were calculated as prescribed in International Commission on Radiological Protection (ICRP) publications 30 and 60. Plasma disappearance curves of (99m)Tc-labeled murine antibody ior C5 were best fit by a two-compartment model in all patients with (t(1/2alpha)) of 4.32 +/- 2.18 h and (t(1/2beta) of 32.6 +/- 3.82 h. Among the main target organs, accumulation of the radiolabeled antibody was found in liver (9.38 +/- 0.80%), heart (8.92 +/- 0.94%) and spleen (1.37 +/- 0.30%) at 5 min post-administration. These values were reduced at 24 h to (5.91 +/- 0.73%) and (0.62 +/- 0.22%), respectively, for the heart and spleen and increased to (9.78 +/- 1.99%) for liver. Estimates of radiation absorbed dose to normal organs in rad/mCi administered were: whole body, 0.0181 +/- 0.0017; heart wall, 0.0768 +/- 0.0090; kidneys, 0.0530 +/- 0.0260; liver, 0.0565 +/- 0.0109 and spleen, 0.0540 +/- 0.0128. The effective dose equivalent and effective dose estimates for adults were 0.0314 +/- 0.0031 and 0.0249 +/- 0.0027 rem/mCi administered. This feasibility study indicates that the O-linked glycoprotein carbohydrate chain TAA ior C2 is expressed in primary and metastatic colorectal carcinomas and shows very limited expression in normal adult tissues. The very good pattern of biodistribution of (99m)Tc-labeled mAb ior C5 in patients will allow imaging of colorectal carcinoma lesions.

Autosomal, mtDNA, and Y-chromosome diversity in Amerinds: pre- and post-Columbian patterns of gene flow in South America.

To evaluate sex-specific differences in gene flow between Native American populations from South America and between those populations and recent immigrants to the New World, we examined the genetic diversity at uni- and biparental genetic markers of five Native American populations from Colombia and in published surveys from native South Americans. The Colombian populations were typed for five polymorphisms in mtDNA, five restriction sites in the beta-globin gene cluster, the DQA1 gene, and nine autosomal microsatellites. Elsewhere, we published results for seven Y-chromosome microsatellites in the same populations. Autosomal polymorphisms showed a mean G(ST) of 6.8%, in agreement with extensive classical marker studies of South American populations. MtDNA and Y-chromosome markers resulted in G(ST) values of 0.18 and 0.165, respectively. When only Y chromosomes of confirmed Amerind origin were used in the calculations (as defined by the presence of allele T at locus DYS199), G(ST) increased to 0.22. G(ST) values calculated from published data for other South American natives were 0.3 and 0.29 for mtDNA and Amerind Y chromosomes, respectively. The concordance of these estimates does not support an important difference in migration rates between the sexes throughout the history of South Amerinds. Admixture analysis of the Colombian populations suggests an asymmetric pattern of mating involving mostly immigrant men and native women.

Microsatellites provide evidence for Y chromosome diversity among the founders of the New World.

Recently, Y chromosome markers have begun to be used to study Native American origins. Available data have been interpreted as indicating that the colonizers of the New World carried a single founder haplotype. However, these early studies have been based on a few, mostly complex polymorphisms of insufficient resolution to determine whether observed diversity stems from admixture or diversity among the colonizers. Because the interpretation of Y chromosomal variation in the New World depends on founding diversity, it is important to develop marker systems with finer resolution. Here we evaluate the hypothesis of a single-founder Y haplotype for Amerinds by using 11 Y-specific markers in five Colombian Amerind populations. Two of these markers (DYS271, DYS287) are reliable indicators of admixture and detected three non-Amerind chromosomes in our sample. Two other markers (DYS199, M19) are single-nucleotide polymorphisms mostly restricted to Native Americans. The relatedness of chromosomes defined by these two markers was evaluated by constructing haplotypes with seven microsatellite loci (DYS388 to 394). The microsatellite backgrounds found on the two haplogroups defined by marker DYS199 demonstrate the existence of at least two Amerind founder haplotypes, one of them (carrying allele DYS199 T) largely restricted to Native Americans. The estimated age and distribution of these haplogroups places them among the founders of the New World.

A way to reduce the radius of rotation in brain SPET with a single-head system.

To optimize spatial resolution in single photon emission tomography (SPET), it is essential to minimize the radius of rotation. In brain studies, different methods have been used to avoid shoulder interference when the radius of rotation is minimized: rectangular fields of view, modifications to the shielding around circular detectors and fan or cone beam collimators. However, few single-head systems can adopt these developments, particularly older cameras. A non-standard image acquisition method to reduce the radius of rotation in brain SPET with a single-head gamma camera is presented. The method applies a defined transformation to the original acquired images, maintaining the whole of the brain inside the field of view without shoulder interference and meeting the condition: pixel size < or = FWHM/3. With this method, it is possible to reduce the radius of rotation to 16 cm and to obtain a transaxial spatial resolution of 15.98 mm, which is 3.5 mm less than with the standard method used in our laboratory. This procedure was implemented for a Siemens Gammasonics ZLC 3700 gamma camera and has been validated in single-slice brain phantom studies. The method has the advantage of not requiring any complex or costly hardware.

A way to reduce the radius of rotation in brain SPET with a single-head system

To optimize spatial resolution in single photon emission tomography (SPECT), it is essential to minimize the radius of rotation. In brain studies, different methods have been used to avoid shoulder interference when the radius of rotation is minimized: rectangular fields of view, modifications to the shielding around circular detectors and fan or cone beam collimators. However, few single-head systems can adopt these developments, particularly older cameras. A non-standard image acquisition method to reduce the radius of rotation in brain SPET with a single-head gamma camera is presented. The method applies a defined transformation to the original acquired images, maintaining the whole of the brain inside the field of view without shoulder interference and meeting the condition: pixel size <= FWHM/3. With this method, it is possible to reduce the radius of rotation to 16 cm and to obtain a transaxial spatial resolution of 15.98 mm less than with the standard method used in our laboratory. This procedure was implemented for a Siemens Gammasonics ZLC 3700 gamma camera and has been validated in single-slice brain phantom studies. The methods has the advantage of not requiring and complex or costly hardware (AU)

Technetium-99m-antiepidermal growth factor-receptor antibody in patients with tumors of epithelial origin: part II. Pharmacokinetics and clearances.

UNLABELLED: Radiolabeled antitumor antibodies hold promise for diagnostic imaging and therapy in oncology. The purpose of this study was to investigate the pharmacokinetics, clearances and possible differences of two dosage administrations of the 99mTc-labeled antiepidermal growth factor (EGF)-receptor antibody and to predict the best dose and schedule for future clinical evaluations of this radiopharmaceutical. METHODS: Nine patients (4 women, 5 men; mean age 46.4 +/- 14.0 yr) were administered 1-3 mg 99mTc-labeled anti-EGF-receptor antibody (a murine IgG2a isotype) by intravenous bolus infusion. After administration, blood samples were collected from 7 patients from an antecubital vein opposite to the injection side at intervals from 2 min to 24 hr after injection, and plasma samples were obtained for pharmacokinetic analysis. Appropriate plasma samples were examined for isotope clearance (i.e., microCi/ml at various intervals) and 99mTc complexation to plasma proteins by fast protein liquid chromatography (FPLC) analysis. Urine was collected from each patient at 3 hr intervals up to 24 hr after monoclonal antibody administration to monitor 99mTc clearance. Plasma time-activity curves were fitted to a two-compartment model using nonlinear least-squares regression analysis by the method of flexible polyhedrals. RESULTS: Plasma disappearance curves of 99mTc-labeled anti-EGF-receptor antibody were best fit by biexponential equation with a distribution half-life (t(1/2alpha)) of 0.137 +/- 0.076 hr (n = 7) and elimination half-life (t(1/2beta)) of 20.3 +/- 8.0 hr. Analysis of urine showed that activity clearance by this route amounted to 4.9% +/- 0.6% of the injected dose in 24 hr, and FPLC analysis showed no evidence of decomposition, only 6%-7% of 99mTc was in a low molecular weight species. CONCLUSION: Plasma pharmacokinetics and urine clearance indicate comparability in both doses. The pharmacokinetic properties of the 99mTc-labeled anti-EGF-receptor antibody were found to be dose-independent. These findings provide an initial characterization of the radiopharmaceutical disposition in patients and may be used as the basis for calculating a better estimate of biodistribution and dosimetry for patients who will receive 188Re-labeled anti-EGF-receptor antibody (MAb ior egf/r3) injection for radioimmunotherapy and warrants further controlled clinical trials to define the efficacy of the radiopharmaceutical.

Laboratory of Caribbean Brain Research Organization in the decade of the brain midpoint. Results in reaching behavior--interferences of subcortical motor centers, neurotransmitter blocking and brain function modeling.

CARIBRO was founded in response to the United Nations declaration that the 1990s be designated the Decade of the Brain. The Program of Action is: 1. Annual meetings; 2. Training courses of the Caribbean School of Neurosciences; 3. Network scientific programs; 4. Fellowship programs; and 5. Dissemination of information on neuroscience. In the same program, a CARIBRO Laboratory was created in one of the Medical Faculties of Havana with the aim to teach students from the Caribbean in neuroscience research. As part of this program, we have been working in lateralized motor functions. Preliminary results in rats show that reaching acquisition allows classification of the animals as right-handed (40%), left-handed (40%), and ambidextrous (20%). Electrolytic lesion of caudate nucleus or amygdala impairs lateralized response. Contralateral lesions increase reaching attempts. Ipsilateral lesions to the preferred forepaw do not affect the reaction. The results remain the same 10, 20, and 90 d after the interference. Pharmacological experiments showed that trihexiphenidil (0.1 mg/kg i.p.) induced handedness reversion in 50% if the animals, whereas haloperidol (1 mg/kg i.p.) produced immobility, tremor, and autonomic symptoms. This effect remained the same in young as well as in old animals. We are also working on mathematical modelation. In this sense, preliminary reports about a model for synaptic modification in the framework of the Fukushima hypothesis is discussed.

Estudio electroforetico de aminoácidos excretados por orina de niños sanos menores de dos años de edad Medellín 1990 / Electrophoresis study of aminoacids excreted in urine of healthy children under two years of age. Medellín 1990

Estudio observacional, descriptivo, prospectivo, realizado con el objetivo de determinar mediante electroforesis las relaciones porcentuales de aminoácidos excretados en una muestra de orina recolectada en niños de tres grupos etáreos: Recién nacidos a término: 46 pacientes (35.7 por ciento) Recién nacidos pretérmino: 43 pacientes (33.3 por ciento) Lactantes (menores de dos anos de edad) 40 pacientes (31 por ciento). Los promedios obtenidos fueron los siguientes: Recién nacidos a término: Taurina: 19 por ciento Glutamina: 17 por ciento Glicina, Histidina y Alanina: 12 por ciento Serina: 9 por ciento Fenilanina: 8 por ciento Lisina: 6 por ciento Triptofano: 5 por ciento En el grupo de recién nacidos pretérmino los valores porcentuales obtenidos fueron: Glutamina: 26 por ciento Histidina: 15 por ciento Alanina: 14 por ciento Fenilalanina: 3 por ciento Glicina: 13 por ciento Serina y Taurina: 9 por ciento Acido Aspártico: 6 por ciento Triptofano y Lisina: 2 por ciento En el tercer grupo etáreo, constituído por lactantes (menores de dos anos), los porcentajes se dieron de la siguiente manera: Glutamina: 20 por ciento Serina y Glicina: 17 por ciento Alanina: 14 por ciento Histidina: 13 por ciento Fenilalanina: 8 por ciento Lisina: 7 por ciento Taurina y Triptofano: 2 por ciento No se encontró correlación lineal, entre la edad materna, el Apgar (tanto al minuto como a los cinco minutos) y los niveles de cada aminoácido. No hay variación estadísticamente significativa de los valores discriminados por sexo, peso al nacer, enfermedades durante el embarazo y el parto y drogas administradas. Los hallazgos del siguiente estudio no fueron comparados con estudios anteriores, debido a que esta investigación es precursora dentro de este tema...

Unilateral striatal grafts induce behavioral and electrophysiological asymmetry in rats with bilateral kainate lesions of the caudate nucleus

Rats (n=11) with bilateral kainate lesions of the caudate nucleus and subsequen unilateral transplantation of embryonic striatal tissue into the damaged area prefered 4 months later to reach for food with the forepaw contralateral to the graft. No such asymmetry was observed in lesioned, nontransplanted (n=8) or unoperated (n=5) control rats. Good integration of the graft with the host brain was indicated by the fnding that cortical spreading depression did not enter the lesioned caudate nucleus but did penetrate into the lesioned caudate with the graft almos as regulary as in intact rats. Behavioral asymmetry produced by unilateral grafts in bilaterally lesioned animals reveals the effects of transplantation with more sensitivity than the graft-induced compensation of the asymmetries caused by unilateral lesions (AU)

Unilateral striatal grafts induce behavioral and electrophysiological asymmetry in rats with bilateral kainate lesions of the caudate nucleus

Rats (n=11) with bilateral kainate lesions of the caudate nucleus and subsequen unilateral transplantation of embryonic striatal tissue into the damaged area prefered 4 months later to reach for food with the forepaw contralateral to the graft. No such asymmetry was observed in lesioned, nontransplanted (n=8) or unoperated (n=5) control rats. Good integration of the graft with the host brain was indicated by the fnding that cortical spreading depression did not enter the lesioned caudate nucleus but did penetrate into the lesioned caudate with the graft almos as regulary as in intact rats. Behavioral asymmetry produced by unilateral grafts in bilaterally lesioned animals reveals the effects of transplantation with more sensitivity than the graft-induced compensation of the asymmetries caused by unilateral lesions

Electrofisiología de crisis epilépticas experimentales: IV. Mecanismos de propagación de las descargas epilépticas / Experimental epileptic seizure electrophysiology: IV. Dissemination mechanisms of the epileptic discharges

El estudio de los mecanismos de propagación de la crisis epiléptica, es de importancia para el conocimiento del desarrollo de las crisis clínicas y electroencefalográficas desde su inicio, ya en forma explosiva o a punto de partida de las descargas interictales, permitiendo explicar al mismo tiempo la forma en que estos ataques tienen lugar en diferentes pacientes. En el presente trabajo se discuten las distintas posibilidades que se han planteado en relación a estos mecanismos, particularizando en los mecanismos intracorticales de propagación, los que tienen lugar a través de vías extracorticales largas y el papel que juegan un conjunto de estructuras facibilatoras e inhibidoras del sistema nervioso central (SNC) (AU)

Electrofisiología de crisis epilépticas experimentales: IV. Mecanismos de propagación de las descargas epilépticas / Experimental epileptic seizure electrophysiology: IV. Dissemination mechanisms of the epileptic discharges

El estudio de los mecanismos de propagación de la crisis epiléptica, es de importancia para el conocimiento del desarrollo de las crisis clínicas y electroencefalográficas desde su inicio, ya en forma explosiva o a punto de partida de las descargas interictales, permitiendo explicar al mismo tiempo la forma en que estos ataques tienen lugar en diferentes pacientes. En el presente trabajo se discuten las distintas posibilidades que se han planteado en relación a estos mecanismos, particularizando en los mecanismos intracorticales de propagación, los que tienen lugar a través de vías extracorticales largas y el papel que juegan un conjunto de estructuras facibilatoras e inhibidoras del sistema nervioso central (SNC)

Electrofisiología de crisis epilépticas experimentales I-Bosquejo hstórico de las epilépsias, conceptos y clasificaciones / Electrophysiology of the experimental epileptic seizure 1. historical background of the epilepsies, concepts and classification

Se presenta el primer trabajo de una serie de artículos donde se analizan aspectos de la electrofisiología de las crisis epilépticas experimentales. Se efectúa un bosquejo histórico del desarrollo de las concepciones sobre la epilépsia que han tenido lugar desde la antigüedad hasta nuestros días. Por otra parte, se sumarizan los conceptos principales y clasificaciones más empleadas del síndrome epiléptico en la actualidad(AU)