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INTRODUCTION AND AIMS: Colorectal cancer is among the three most common cancers worldwide. Knowledge and identification of suboptimal outcome-associated factors enable comprehensive patient management. The aim of the present study was to present the results of the surgical management of colorectal cancer at a quaternary care university hospital. MATERIALS AND METHODS: An observational, analytic, cross-sectional study was conducted. Information was collected on a retrospective cohort of patients diagnosed with colorectal cancer from 2013 to 2017 at the Hospital Universitario Mayor Méderi, Bogotá, Colombia. RESULTS: Data on 452 patients, within the study period, were collected. A total of 48.5% of the patients were men, the overall complication rate was 24%, the surgical site infection (SSI) rate was 15.38%, anastomotic dehiscence occurred in 4.18% of the patients, bleeding required reoperation in 1.32%, and the intrahospital mortality rate was 7.47%. CONCLUSION: Colorectal cancer management at a university hospital was as beneficial as that provided by other types of hospitals, showing a direct association with complete R0 dissections; low complication rates, according to international reports; and reduced overall morbidity.
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Local electric fields generated by the electric organ discharge of Gymnotus carapo were explored at selected points on the skin of an emitter fish ('local self-generated fields') and on the skin of a conspecific ('local conspecific-generated fields') using a specially designed probe. Local self-generated fields showed a constant pattern along the body of the fish. At the head, these fields were collimated, much stronger than elsewhere on the fish, and had a time waveform that was site-independent. This waveform consisted of a slow head-negative wave followed by a faster head-positive wave. In contrast, time waveforms in the trunk and tail regions were site-specific, with field vectors that changed direction over time. Local conspecific-generated fields were similar to the head-to-tail field, but their spatio-temporal pattern at the skin depended on the relative orientation between the receiving fish and the emitting fish. Because self-generated fields had a slow early component at the head region, they displayed a low-frequency peak in their power spectral density histograms. In contrast, the conspecific-generated fields had time waveforms with a sharper phase reversal, resulting in a peak at higher frequency than in the self-generated field. Lesions in emitting fish demonstrated that waveform components generated by the trunk and tail regions of the electric organ predominate in conspecific-generated fields, whereas waveform components generated by the abdominal region prevail in self-generated fields. Similar results were obtained from Brachyhypopomus pinnicaudatus. These results suggest that, in pulse-emitting gymnotids, electrolocation and electrocommunication signals may be carried by different field components generated by different regions of the electric organ.
Assuntos
Peixe Elétrico/fisiologia , Órgão Elétrico/fisiologia , Comunicação Animal , Animais , Eletrofisiologia , MasculinoRESUMO
This paper describes the peripheral mechanisms involved in signal processing of self- and conspecific-generated electric fields by the electric fish Gymnotus carapo. The distribution of the different types of tuberous electroreceptor and the occurrence of particular electric field patterns close to the body of the fish were studied. The density of tuberous electroreceptors was found to be maximal on the jaw (foveal region) and very high on the dorsal region of the snout (parafoveal region), decaying caudally. Tuberous type II electroreceptors were much more abundant than type I electroreceptors. Type I electroreceptors occurred exclusively on the head and rostral trunk regions, while type II electroreceptors were found along as much as 90 % of the fish. Electrophysiological data indicated that conspecific- and self-generated electric currents are 'funnelled' by the high conductivity and geometry of the body of the fish. These currents are concentrated at the peri-oral zone, where most electroreceptors are located. Moreover, within this region, field vector directions were collimated, constituting the most efficient stimulus for electroreceptors. It can be concluded that the passive properties of the fish tissue represent a pre-receptor device that enhances exafferent and reafferent electrical signals at the fovea-parafoveal region.