Decerebration induced by surgical transection of cerebral ganglion of crayfish

Background: Since the neural structures of the crayfish brain closely resemble their equivalent in the mammals. This can be suggested by observing the similarity that exists in the brain divided by the surgical transection of the crayfish brain in which the protocerebrum remains attached to the first two cranial nerves, findings also described by Frederic Bremer in 1935 in cats with cerebral transection.Methods: Total 11 Adult male crayfish were trained to respond with defense reflex, the animals were placed in water at 0°C, remained without any movement, and subsequently through a small incision of 3 mm in diameter in the medial antero region and dorsal cephalothorax region, a surgical section of the cerebral ganglion was performed. Immediately after surgery, metal microelectrodes were implanted to collect the activity of the photoreceptors and visual fibers.Results: Once the defense reflex begins to recover in previously decerebrated crayfish, it means that it shows signs of reconnection. The isolated protocerebrum with the deutocerebrum olfactory lobe remain alive for several days and the neuronal connections were reestablished, as measured throughout the bilateral defense activity. The defense reflex was observed in all animals and then recovered after surgery.Conclusions: The crayfish is an excellent model to work the visual activity, all coding of visual information was suppressed in de-cerebrated crayfish. The recovery of the neural disconnection is observed from 40 days, where the defence reflex appears again before visual stimuli.

Microvascular skin coverage in wounds that expose the Achilles tendon

Achilles tendon rupture is one of the most frequent tendon ruptures. Surgical intervention is the best option, but it has a high rate of complications leading to skin infections and necrosis. Extensive and aggressive debridement is necessary, producing tendon exposure and large skin defects. There are many alternatives for the skin coverage of the Achilles tendon, like sequential closures, vacuum assisted closure, local flaps, regional flaps, and more recently and efficiently microsurgery flaps. Skin defects in the Achilles tendon region have many peculiarities in comparison with other parts of the body: it is a zone that is always under mechanical stress due to footwear, this is why it must be highly resistant but thin. Its coverage must have sensitive properties, endure tendon gliding and allow early rehabilitation. Sometimes tendon reinforcement or creation or a neo tendon will be needed. For fulfilling these requirements free flaps by microsurgery are the only option in 90% of the cases. In this review article, we analyze three of the most frequently used free flaps in reconstructive medicine for complex Achilles tendon defects; free radial forearm flap, free radial forearm flap with vascularized flexor carpi radialis tendon and free anterolateral thigh (ALT) flap with vascularized fascia lata. This choice will be determined by the number of tissues involved, size of the defect, etiology of the defect, overall condition of the affected extremity and quality of neighboring tissues

Thoracic limb salvage by fibular free flap

The treatment of most fractures of the ulna and radius is usually performed by anatomical reduction and internal fixation, when damage is extensive and local soft tissue cannot provide a complete wound coverage, locoregional flaps present a suitable reconstructive benefit. A 35-year-old male patient suffered an exposed diaphysio-metaphyseal fracture with multi-fragmented distal radius. The patient was evaluated during a 10-day period at the National Institute of Rehabilitation, where the osteosynthesis material and a severe infectious process with necrosis were identified. Necrosectomy of the posterior compartment and removal of the osteosynthesis material was performed, a skin defect of approximately 22x16 cm was observed with a bone gap of 6 cm of radius and ulna. a fibula-free flap is placed to correct the skin defect and an external fixative used for bone alignment. The fibular free flap presents an excellent therapeutic alternative in the resolution of bone gaps with extensive skin defect. Whenever a trained microsurgery team is available, current scales of limb injury should be considered but not utilized for therapeutic approach, always trying to shift amputation as the first option, to the very last one of them

Use of rivaroxaban and acetylsalicylic acid as a combined treatment for peripheral arterial disease in Central Military Hospital

Background: The objective of this research was to evaluate the behavior of 3 risk indicators for peripheral arterial disease in patients under oral treatment with rivaroxaban 2.5 mg every 12 hours plus, acetylsalicylic acid 100 mg every 24 hours. It was hypothesized that the oral combination of rivaroxaban and acetylsalicylic acid presents a therapeutic advantage over other treatments.Methods: A prospective longitudinal and non-randomized study of a single center was performed. 59 patients with peripheral arterial disease were included and treated with acetylsalicylic acid + rivaroxaban. Peak systolic velocity, ankle-brachial index and C reactive protein index were evaluated.Results: Significant changes were found at month 1 and 3 of follow-up in maximum systolic velocity, ankle-arm index and C-reactive protein index. The baseline peak systolic velocity (PSV) in the anterior tibial artery had significant differences after one month of treatment (p=0.001) and after 3 months (p=0.001). The baseline PSV in the posterior tibial artery had significant differences compared to the values found at the month of treatment (p=0.001) and 3 months (p=0.001). In the ankle-brachial index a baseline median of 0.790 was found, one month after the treatment of 0.795 (p=0.147) and 3 months after 0.800 (p=0.019). The mean baseline C-reactive protein obtained was 73.142 mg/l, at one month 87.233 mg/l (p=0.001) and at 3 months at 79.009 mg/l (p=0.294) with a standard deviation of 67.18, 74.78 and 69.69 respectively.Conclusions: The combined use of acetylsalicylic acid and rivaroxaban allows a clinical improvement in patients with peripheral arterial disease

The neurobiology of splitbrain crayfish

Background: They crayfish brain is segmented into two symmetrical hemiganglia. Normally both hemiganglia are in direct communication through a series of well-defined neural bridges that cross de midline to form reciprocal cross connections.Methods: An original study was carried out in the Department of Physiology of the Faculty of Medicine, UNAM during the period from August 2019 to August 2020. 13 Crayfish Procambarus clarkii weighing between 1g to 30g were used. Each eyestalk of the animals was tied to a displacement transducer coupled with a polygraph so that optomotor or electrical activity was bilaterally recorded. The separation of the right from the left hemiganglia from the cerebral or supraesophageal ganglion was performed with a sagittal section, splitbrain (SB).Results: The normal photo motor reflex in crayfish eye is measured as a gradual decrease in the ERG amplitude. During tactile stimulation, the visual activation of both eyestalks in normal crayfish leads to a highly regular bilateral activity. The regular activity can only be altered by disturbing the mechanoreceptors located in the shell surrounding the eyestalks.Conclusions: The procedure presented in this article provides unique characteristics for the study of the nervous system such as a detailed response of the bilateral optomotor reflex

Chronic venous insufficiency: a review

Chronic venous insufficiency (CVI) comprises a complete spectrum of morphological and functional abnormalities of the venous system1 including any long-term functional and morphological alteration. CVI accounts for several abnormalities of the venous system. It is a highly prevalent disease that causes serious economic consequences, a decrease in the quality of life and can lead to serious complications. An exhaustive review was performed with the available literature, using the PubMed, ScienceDirect, Scopus and Cochrane databases from 2004 to 2021. The search criteria were formulated to identify reports related to chronic venous insufficiency. The pathophysiology of chronic venous insufficiency begins with chronic venous hypertension and the dilation of the vessel, this leads to a series of pathological changes in the venous wall and surrounding tissues, in advanced stages of CVI, skin lesions are associated with an increased proliferation of skin capillaries and microcirculatory abnormalities that may be the result of an altered level of factors responsible for the angiogenic response, such as vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2) and angiostatin. In this review, updates on pathophysiology, clinic, diagnosis, classification and treatment of this disease are analyzed, with special emphasis on therapeutic options. Chronic venous insufficiency is a disease that affects the patient at several levels, mainly diminishing his/her quality of life. Currently there are various treatments ranging from habit modifications, pharmacological, to endovenous and surgical treatment.