Signal transduction is the process of routing information inside cells when receiving stimuli from their environment that modulate the behavior and function. In such biological processes, the receptors, after receiving the corresponding signals, activate a number of biomolecules which eventually transduce the signal to the nucleus. The main objective of our work is to develop a theoretical approach which will help to better understand the behavior of signal transduction networks due to changes in kinetic parameters and network topology. By using an evolutionary algorithm, we designed a mathematical model which performs basic signaling tasks similar to the signaling process of living cells. We use a simple dynamical model of signaling networks of interacting proteins and their complexes. We study the evolution of signaling networks described by mass-action kinetics. The fitness of the networks is determined by the number of signals detected out of a series of signals with varying strength. The mutations include changes in the reaction rate and network topology. We found that stronger interactions and addition of new nodes lead to improved evolved responses. The strength of the signal does not play any role in determining the response type. This model will help to understand the dynamic behavior of the proteins involved in signaling pathways. It will also help to understand the robustness of the kinetics of the output response upon changes in the rate of reactions and the topology of the network.
Tracheoesophageal puncture with placement of a voice prosthesis (VP) provides successful speech rehabilitation after total laryngectomy. However, enlargement of the tracheoesophageal puncture is a challenging complication as it results in leakage around the VP into the airway and may eventually lead to aspiration pneumonia and respiratory complications. It necessitates removal of the VP and permanent closure of the tracheoesophageal fistula. We present our own experience for surgical closure of persistent tracheoesophageal puncture. A non-controlled prospective study was conducted at the Department of Oto-Rhino-Laryngology and Head and Neck Surgery, Zagazig University Hospitals, Zagazig, Egypt. This study included five patients with an enlarged tracheoesophageal puncture. They had persistent leakage around the VP with resulting recurrent chest infections. None of the patients underwent previous surgical intervention for closure of the tracheoesophageal fistula. This surgical technique involved identification and exposure of the tracheoesophageal fistula tract by blunt dissection and its ligation by non-resorbable sutures at two points close to the posterior wall of the trachea without dividing the fistula tract. The mean follow-up period was 14.4 months. Successful closure of the fistula was achieved in all patients (100%). All patients tolerated full diet well and had uneventful recovery and no further episodes of aspiration. This surgical technique is simple, easily feasible technically, and effective. It enables early oral feeding and allows a short hospital stay, thus increasing the patient's comfort.
Hypoxia most often occurs in cancer and the occurrence of hypoxia helps the cells in adapting different responses than the normal such as the activation of of those signaling pathways which regulate proliferation, angiogenesis, and cell death. There are large number of genes which are known to be associated with diverse biological processes and their control and coordination and in different cancers, the hypoxia-response differs. In this study our goal is to understand the impact of alteration in expression of hypoxia and immune systems related genes and its survival in breast cancer and analyzed the hallmarks of molecular signatures. For this purpose we have collected the hypoxia-associated genes based on the literature related with diverse biological processes and functions. For all these genes, we have studied the survival analysis, breast cancer gene expression profiling, and relevant hypoxic genes alterations. Based on our study, we conclude that there are 17 critical pathways and 40 genes from hypoxic gene list appear to play the major roles in case of breast cancer and overall we observe that immune signaling pathways and its components are highly altered in case of breast cancer. Among the top raked hallmarks of molecular signatures are apoptosis, hypoxia, DNA repair, E2F targets, MYC targets, androgen and estrogen response, and TNFa signaling.
A laryngocele is an abnormal dilatation of the laryngeal saccule. It is a rare benign lesion of the larynx. Various modalities of treatment have been advocated for its management. We present our treatment results and outcomes of a series of cases of laryngoceles and discuss the concepts of their management. This study included patients with different laryngocele types. Patients with an internal laryngocele underwent endoscopic CO 2 laser resection, while those with a combined laryngocele underwent resection via a V-shaped lateral thyrotomy approach. Seven patients had an internal laryngocele, and 4 patients had a combined laryngocele. Hoarseness and neck swelling were the most common symptoms. The mean followup period was 8.5 months. None of the patients needed a tracheostomy either preoperatively or postoperatively, or had recurrence of laryngocele. We advocate the lateral thyrotomy approach for combined laryngoceles as it provides safe, precise, and complete resection under direct visualization via a single approach, while we favor the endoscopic laser approach for the internal ones as it allows resection of the entire lesion with minimal laryngeal trauma, less operative time, and a shorter hospital stay.
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