Hospital Radiopharmacy in Argentina during the COVID-19 pandemic. Criteria and rationale for the organization of work. / Radiofarmacia Hospitalaria en Argentina durante la pandemia de COVID-19. Criterios y fundamentos para la organización del trabajo.

This publication presents criteria and bases for the work organization in the safe practice of Hospital Radiopharmacy, in order to minimize the risk of viral transmission during the COVID-19 pandemic, in a reference facility of the National Energy Commission Atomic of Argentina, while continuing to perform essential services for the health system. For this purpose, documents from the National Energy Commission Atomic, IAEA, WHO and other scientific publications were consulted as reference. These recommendations are under constant review and are permanently updated. Within this framework, the present model of work organization for this essential activity is proposed, including general and specific recommendations and its epidemiological and immunological basis.

Cortical stroke affects activity and stability of theta/delta states in remote hippocampal regions.

Cognitive impairment is a common outcome of ischemic stroke. Our previous work has shown that an experimental stroke in the cortex reduces activity in remote hippocampal layers in rats. This study seeks to uncover the underlying functional connections between these areas by analyzing changes to oscillatory activity, signal power, and communication. We induced an ischemic stroke in the left somatosensory cortex of rats and used linear micro-electrode arrays to simultaneously record from cortex and hippocampus under urethane anesthesia at two weeks and one month after stroke. We found significant increase in signal power, as well as an increase in the number of brain state changes in response to stroke. Our results suggest that the cortex modulates the activity and stability of hippocampal oscillations, which is disrupted following cortical stroke that can lead to cognitive impairment.

Prediction of regional functional impairment following experimental stroke via connectome analysis.

Recent advances in functional connectivity suggest that shared neuronal activation patterns define brain networks linking anatomically separate brain regions. We sought to investigate how cortical stroke disrupts multiple brain regions in processing spatial information. We conducted a connectome investigation at the mesoscale-level using the neuroVIISAS-framework, enabling the analysis of directed and weighted connectivity in bilateral hemispheres of cortical and subcortical brain regions. We found that spatial-exploration induced brain activation mapped by Fos, a proxy of neuronal activity, was differentially affected by stroke in a region-specific manner. The extent of hypoactivation following spatial exploration is inversely correlated with the spatial distance between the region of interest and region damaged by stroke, in particular within the parietal association and the primary somatosensory cortex, suggesting that the closer a region is to a stroke lesion, the more it would be affected during functional activation. Connectome modelling with 43 network parameters failed to reliably predict regions of hypoactivation in stroke rats exploring a novel environment, despite a modest correlation found for the centrality and hubness parameters in the home-caged animals. Further investigation in the inhibitory versus excitatory neuronal networks and microcircuit connectivity is warranted to improve the accuracy of predictability in post-stroke functional impairment.

[99mTc-ceftizoxime scintigraphy in normal rats and abscess induced rats]. / Gammagrafía con 99mTc-ceftizoxima en ratas normales y en ratas con absceso inducido.

UNLABELLED: This study aimed to investigate the biodistribution of the 99mTc-ceftizoxime in normal rats and in rats bearing septic and sterile induced abscess. MATERIAL AND METHODS: Three groups of rats were studied. a) Six normal rats b) 15 rats with E. coli induced abscess and c) 15 rats with sterile zymosan induced abscess. Septic abscess was induced with 2 x 10(8) colony forming units of E. coli and sterile one with 0.1 mL of 5% sterile Zymosan. 24 h after the abscess induction, 12 MBq of 99mTc-CFT were injected iv. and whole body images were collected at 30 min, 1, 2, 4 and 6 h p.i. Areas of interest were drawn and lesion/background index was calculated. The 6 normal rats were scanned at the same times, killed at 6 h p.i and kidney, liver, spleen, lung, heart and muscle activity were measured. Each organ was weighed, cut and its activity measured. Parallelly, the biological activity of the labeled antibiotic and its binding to the E. coli and S. aureus bacteria were analyzed. RESULTS: High biliary excretion was seen in all rats. Organ measurement showed the maximal uptake in kidney and very low uptake in muscles. Mean +/- s.d abscess/background ratio at 30 min, 1, 2, 4 and 6 h were 2.60 +/- 0.36, 2.67 +/- 0.66, 2.6 0 +/- 0.58, 2.78 +/- 0.84, 3.24 +/- 1.00 for septic abscess and 2.37 +/- 0.39, 2.10 +/- 0.38, 1.97 +/- 0.34, 1.82 +/- 0.25, 1.65 +/- 0.23 for aseptic abscess. The 99mTc-CFT uptake was significantly higher in the septic abscess than in sterile one (p < 0.05). The 99mTc-CFT uptake in the septic abscess remains stable or increases until along the 6 h. The 99mTc-CFT uptake in the aseptic abscess decreases along the time. CONCLUSIONS: The scintigraphy with 99mTc-CFT seems able to differentiate sterile inflammation from infection. High biliary excretion limits its application in abdomen. Main application could be diagnosis of osteoarticular infection.

Radiofarmacia Hospitalaria en Argentina durante la pandemia de COVID-19. Criterios y fundamentos para la organización del trabajo / Hospital Radiopharmacy in Argentina during the COVID-19 pandemic. Criteria and rationale for the organization of work

En esta publicación se presentan criterios y fundamentos para la organización del trabajo en la práctica segura de la Radiofarmacia Hospitalaria, a fin de minimizar el riesgo de transmisión viral durante la pandemia de COVID-19, en una instalación de referencia de la Comisión Nacional de Energía Atómica de Argentina, mientras se continúan desempeñando servicios esenciales para el sistema de salud. Con este fin se consultaron como referencia documentos de la Comisión Nacional de Energía Atómica, OIEA, la OMS y otras publicaciones científicas. Estas recomendaciones se encuentran en proceso de revisión constante y son actualizadas de manera permanente. En este marco se propone el presente modelo de organización laboral para esta actividad esencial incluyendo recomendaciones generales, particulares y su fundamento epidemiológico e inmunológico

This publication presents criteria and bases for the work organization in the safe practice of Hospital Radiopharmacy, in order to minimize the risk of viral transmission during the COVID-19 pandemic, in a reference facility of the National Energy Commission Atomic of Argentina, while continuing to perform essential services for the health system. For this purpose, documents from the National Energy Commission Atomic, IAEA, WHO and other scientific publications were consulted as reference. These recommendations are under constant review and are permanently updated. Within this framework, the present model of work organization for this essential activity is proposed, including general and specific recommendations and its epidemiological and immunological basis

Effect of caffeine on the memory of the mouse.

Albino mice were injected i.p. with caffeine (27.9 mg/kg) 10 min pre-trial. The mice had no trial retention (300-s period) after 24 h. This result suggests that caffeine, at this dose, would upset some mechanism involved in memory processes. No correlation is observed between serotonin (5-HT) increase and caffeine's effect on retention.

[Labeling of leukocytes using stannous 99mTc-colloid in whole blood samples]. / Marcación de leucocitos utilizando coloide estannoso-99mTc a partir de muestras de sangre entera.

This paper presents the preparation of a radiocolloid that still makes it possible to label leukocytes using its phagocytosis capacity. Given that this function is exclusively of the white blood cells, not being exercised by other blood cells, the use of a stannous fluoride radiocolloid labeled with 99mTc (F2Sn-99mTc) was tested in order to label leukocytes in whole blood samples. Using cellular separation techniques in density gradients and acquisition of images in gamma camera of radioactivity distribution in Percol, it was observed that the white cells labeling achieved was selective and with high efficiency for leukocytes (in all cases, it was superior to 70%), optimal reproducibility, low cost and low cellular toxicity.

Effect on rats and mice of a diet with low tryptophan content (maize flour).

Female Wistar rats when crowded together become aggressive if fed a diet with low tryptophan (Trp) content (maize, flour, Mf). When isolated during 30 days and fed Mf they show a decrease of weight, of total plasma Trp, and of Trp and 5-hydroxytryptamine (5-HT) in brain stem, but 5-hydroxyindolacetic acid (5-HIAA) of the same cerebral area does not change. These results partially agree with other authors observations. Mice isolated during 47 days and fed with Mf do not show any significant weight variation, the hypermotility of isolated mice on normal diet persists, but 5-HT and 5-HIAA significantly decreases in total brain, an effect that has been observed by another author. The effect on 5-HIAA does not depend on the diet, either balanced or with low Trp content.

Role of ACTH on the effect of medroxyprogesterone in brain stem serotonin.

PIP: A clinical study with 361 female rats was conducted to elucidate the mechanism whereby MPA (medroxyprogesterone acetate) lowers 5-HT/5-HIAA ratio in the brain area and the possible role of serotoniergic mechanisms. In addition, the participation of MAO (monoamino oxidase) system and the effects of some steroids were studied in order to establish a relationship between chemical structure and activity. The effects of the following steroids were studied: MPA (medroxyprogesterone acetate), melengestrol acetate, chlormadinone, pregnenolone, -methyl pregnenolone, DOCA, acetoxi-progesterone, and ACTH (synacthen). Effects of these substances on LTP (liver tryptophan pyrrolase) activity, total and free plasma and brain stem Trp (tryptophan), and the 5HT and 5HTAA content in brain stem are tabulated. Of all the substances, only MPA and melengestrol acetate significantly raised LTP activity and both also lowered 5-HT content of brain stem. The high levels of ACTH in the blood of the adrenalectomized rats, as in those under fasting conditions, antagonized MPA effects. To further test this seeming result, ACTH and ACTH-MPA were injected into another group of animals. The ACTH not only increased plasma corticosterone but also antagonized the effect of MPA on the 5-HT content of brain stem. The study did not identify a relationship between chemical structure of the steroids studied and effects observed.^ieng

Gammagrafía con 99mTc-ceftizoxima en ratas normales y en ratas con absceso inducido / 99mTc-ceftizoxzime scintigraphy in normal rats and abscess induced rats

El objetivo del trabajo fue analizar la biodistribución de la 99mTc-ceftizoxima (CFT) en ratas normales y en ratas con absceso inducido: séptico o estéril. Material y métodos: Se estudiaron 3 grupos de ratas. a) 6 ratas normales; b) 15 ratas en las que se indujo un absceso séptico con 2 x 10 8 unidades formadoras de colonias de Escherichia coli, y c) 15 ratas en las que se indujo un absceso estéril con 0,1 ml de 5 % zymosan estéril. A las 24 h de la inducción del absceso se inyectaron i.v. 12 MBq de 99mTc-CFT y se registraron imágenes de cuerpo entero a los 30 min y 1, 2, 4 y 6 h p.i. Se dibujaron áreas de interés y se calculó el índice lesión/fondo. En las 6 ratas normales se siguió el mismo procedimiento y además al finalizar las últimas imágenes se sacrificaron y se extrajeron riñones, hígado, bazo, corazón pulmones y un fragmento de músculo. Cada órgano, fue pesado, cortado y se midió la actividad que contenía. Paralelamente se analizó la actividad biológica del antibiótico marcado y la unión del mismo a las bacterias E. coli y Staphylococcus aureus. Resultados: Se observó eliminación biliar elevada en todos los animales. El contaje de los órganos mostró la mayor actividad en riñones y actividad muy baja en músculo. El índice medio de actividad lesión/fondo (Media ± d.e.) a los 30 min, 1, 2, 4 y 6 h fue 2,60 ± 0,36, 2,67 ± 0,66, 2,6 0 ± 0,58, 2,78 ± 0,84, 3,24 ± 1,00 en el absceso séptico y 2,37 ± 0,39, 2,10 ± 0,38, 1,97 ± 0,34, 1,82 ± 0,25, 1,65 ± 0,23 en el absceso estéril. La captación de 99mTc-CFT fue significativamente mayor en el absceso séptico que en el estéril (p < 0,05). La captación de 99mTc-CFT en el absceso séptico se incrementa con el tiempo hasta las 6h, mientras que en el estéril disminuye con el tiempo. Conclusión: La gammagrafía con 99mTc-CFT permite diferenciar la inflamación estéril de la infección y se podría aplicar al diagnóstico de la infección osteo-articular. La elevada eliminación renal y biliar limita su aplicación en abdomen

This study aimed to investigate the biodistribution of the 99mTc-ceftizoxime in normal rats and in rats bearing septic y sterile induced abscess. Material y methods: Three groups of rats were studied. a) Six normal rats b) 15 rats with E. coli induced abscess and c) 15 rats with sterile zymosan induced abscess. Septic abscess was induced with 2 x 10 8 colony forming units de E.Coli y sterile one with 0.1 mL de 5 % sterile Zymosan. 24 h after the abscess induction, 12 MBq de 99mTc-CFT were injected iv. and whole body images were collected at 30 min, 1, 2, 4 and 6 h p.i.. Areas of interest were drawn and lesion/background index was calculated. The 6 normal rats were scanned at the same times, killed at 6 h p.i. and kidney, liver, spleen, lung, heart and muscle activity were measured. Each organ was weighed, cut and its activity measured. Parallelly, the biological activity of the labeled antibiotic and its binding to the E. coli and S. aureus bacteria were analyzed. Results: High biliary excretion was seen in all rats. Organ measurement showed the maximal uptake in kidney and very low uptake in muscles. Mean ± s.d abscess/background ratio at 30 min, 1, 2, 4 and 6 h were 2.60 ± 0.36, 2.67 ± 0.66, 2.6 0 ± 0.58, 2.78 ± 0.84, 3.24 ± 1.00 for septic abscess and 2.37 ± 0.39, 2.10 ± 0.38, 1.97 ± 0.34, 1.82 ± 0.25, 1.65 ± 0.23 for aseptic abscess. The 99mTc-CFT uptake was significantly higher in the septic abscess than in sterile one (p < 0.05). The 99mTc-CFT uptake in the septic abscess remains stable or increases until along the 6 h. The 99mTc-CFT uptake in the aseptic abscess decreases along the time. Conclusions: The scintigraphy with 99mTc-CFT seems able to differentiate sterile inflammation from infection. High biliary excretion limits its application in abdomen. Main application could be diagnosis of osteoarticular infection

Marcación de leucocitos utilizando coloide estannoso-99mTc a partir de muestras de sangre entera / Labeling of leukocytes using stannous 99mtc-colloid in whole blood samples

Se presenta la preparación de un radiocoloide que permite la marcación de leucocitos utilizando su capacidad de fagocitosis. Dado que esta función es exclusiva de los glóbulos blancos, no ejerciéndola otras células sanguíneas, se probó la utilización de un coloide de fluoruro estannoso marcado con 99mTc (F2Sn-99mTc) a fin de marcar dichas células en muestras de sangre entera. Mediante técnicas de separación celular en gradientes de densidad y adquisición de imágenes en cámara gamma de la distribución de radioactividad en tubos con Percol 90 por ciento, se observó que la marcación lograda es selectiva y de alta eficiencia para leucocitos (en todos los casos fue mayor del 70 por ciento), óptima reproducibilidad, bajo costo y baja toxicidad celular (AU)

Effect on rats and mice of a diet with low tryptophan content (maize flour)

Female Wistar rats when crowded together become aggressive if fed a diet with low tryptophan (Trp) content (maize, flour, Mf). When isolated during 30 days and fed Mf they show a decrease of weight, of total plasma Trp, and of Trp and 5-hydroxytryptamine (5-HT) in brain stem, but 5-hydroxyindolacetic acid (5-HIAA) of the same cerebral area does not change. These results partially agree with other authors observations. Mice isolated during 47 days and fed with Mf do not show any significant weight variation, the hypermotility of isolated mice on normal diet persists, but 5-HT and 5-HIAA significantly decreases in total brain, an effect that has been observed by another author. The effect on 5-HIAA does not depend on the diet, either balanced or with low Trp content.

Effect on rats and mice of a diet with low tryptophan content (maize flour).

Female Wistar rats when crowded together become aggressive if fed a diet with low tryptophan (Trp) content (maize, flour, Mf). When isolated during 30 days and fed Mf they show a decrease of weight, of total plasma Trp, and of Trp and 5-hydroxytryptamine (5-HT) in brain stem, but 5-hydroxyindolacetic acid (5-HIAA) of the same cerebral area does not change. These results partially agree with other authors observations. Mice isolated during 47 days and fed with Mf do not show any significant weight variation, the hypermotility of isolated mice on normal diet persists, but 5-HT and 5-HIAA significantly decreases in total brain, an effect that has been observed by another author. The effect on 5-HIAA does not depend on the diet, either balanced or with low Trp content.