Effect of Linearization in a WNT Signaling Model.

A nonlinear model consisting of a system of coupled ordinary differential equations (ODE), describing a biological process linked with cancer development, is linearized using Taylor series and tested against different magnitudes of input perturbations, in order to investigate the extent to which the linearization is accurate. The canonical wingless/integrated (WNT) signaling pathway is considered. The linearization procedure is described, and special considerations for linearization validity are analyzed. The analytical properties of nonlinear and linearized systems are studied, including aspects such as existence of steady state and initial value sensitivity. Linearization is a useful tool for speeding up drug response computations or for providing analytical answers to problems such as required drug concentrations. A Monte Carlo-based error testing workflow is employed to study the errors introduced by the linearization for different input conditions and parameter vectors. The deviations between the nonlinear and the linearized system were found to increase in a polynomial fashion w.r.t. the magnitude of tested perturbations. The linearized system closely followed the original one for perturbations of magnitude within 10% of the base input vector which yielded the state-space fixed point used for the linearization.

Tracheal reconstruction using composite nasal septal graft in patients with invasive thyroid carcinoma.

OBJECTIVE: This paper presents a series of three patients who were identified as having partial thickness involvement of the laryngotracheal complex secondary to invasive, well-differentiated thyroid cancer. These patients were managed with full thickness window resection and reconstruction using a composite nasal septal graft. METHODS: A review of the Princess Alexandra Hospital database (comprising prospectively collated data) was undertaken to identify patients who had undergone full thickness tracheal resection and reconstruction using a composite nasal septal graft; demographic, operative technique and survival outcome data were collated. RESULTS: Three patients had a composite nasal septal graft performed for reconstruction of full thickness laryngotracheal defects following the excision of well-differentiated thyroid cancer. There were no cases of local recurrence after a minimum of 18 months' follow up. CONCLUSION: This paper describes our surgical technique for reconstruction of these defects using a composite nasal septal graft. It also presents data on our three cases to date, in which the technique has been used safely. A discussion of the surgical management of locally invasive, well-differentiated thyroid cancer is provided.

Vertebral artery dissection after direct laryngoscopy: case report and literature review.

OBJECTIVE: We report a case of vertebral artery dissection following direct laryngoscopy, and we provide an update on current knowledge regarding this condition and its relationship to movements of the neck. METHOD: A case report and review of the world literature are presented. RESULTS: Vertebral artery dissection is an uncommon event leading to stroke. It has been associated with many risk factors, particularly extreme movement of the cervical spine. The pathogenesis of the condition and the true aetiological significance of neck movement are not known. CONCLUSION: To our knowledge, we present the first case of vertebral artery dissection following direct laryngoscopy. We highlight the need for caution when considering neck pain in patients after direct laryngoscopy.

Computer imaging and patient satisfaction in rhinoplasty surgery.

The measurement and achievement of improved patient benefit following a particular medical or surgical intervention has become an increasingly relevant part of the provision of effective healthcare. We have retrospectively analysed patient satisfaction in 56 patients following rhinoplasty via the Glasgow Benefit Inventory (GBI), 25 of whom underwent pre-operative computer imaging planning. We have also audited patient reaction to this technique via a concurrent questionnaire in those subjects who underwent imaging, and correlated this with overall patient outcome. Patient satisfaction with cosmetic rhinoplasty following computer imaging was significantly improved compared to those patients who did not receive imaging.

In vitro and in vivo investigations on reticuloendotheliosis virus infection.

Experimental transmission of reticuloendotheliosis (RE) in 1-day-old SPF chickens was achieved by intraperitoneal inoculation of cell-associated and cell-free RE virus (REV). REV-inoculated chickens exhibited an immune response throughout the entire observation period. Viremia persisted for 5--6 months in chickens hatched from REV-inoculated SPF embryonated eggs. The natural occurrence of RE was detected in turkey flocks of farms Bc.

[Antiphlogistic and antipyretic effect of sodium salicylate in rats and rabbits]. / Untersuchungen zur antiphlogistischen und antipyretischen Wirkung von Natriumsalizylat bei Ratten und Kaninchen.

Inflammatory processes were provoked in 35 rats by subcutaneous implantation of sterile cotton-wool pads and treated five days by means of various antiphlogistic substances. The action of sodium salicylate (administered alone or in conjunction with gamma-globulin or with glucose) proved similar to that of prednisolone which was given as control substance. Human gamma-globulin exhibited neither anti-inflammatory nor pro-inflammatory effects. Experiments with twelve rabbits revealed that the pyretogenic potential of sodium nucleinate, one per cent (0.01 g/kg body weight) was stronger than that of animal charcoal or peptone. Yet, the two latter substances may be used, as well. The antipyretic effect of sodium salicylate was not as intensive but just as reliable as that of aminophenazone, when both preparations were applied to rabbits with induced fever. Concomitant administration of glucose is recommended to prevent development of undesired side-effects, such as giddiness or ataxia.

Immune response to experimental infection with bovine leukemia virus (BLV) in domestic and laboratory animals.

The immune response to cell-associated and cell-free BLV inoculation was studied in calves, lambs, rabbits and specific pathogen-free chickens. Inoculation of cell-associated or cell-free BLV failed to induce infection in rabbits and chickens (strain PDRC), but resulted in the infection of Holstein-Frize calves and of lambs, which exhibited a specific immune response over the entire observation period. Specific antibodies to glycoprotein and p24 fractions of BLV were detected in the infected animals. BLV could be recovered from serologically positive animals.

Specific protection against bovine leukemia virus infection conferred on cattle by the Romanian inactivated vaccine BL-VACC-RO.

The Romanian BL-VACC-RO vaccine against bovine leukemia virus (BLV) infection was prepared with ethylenimine-inactivated BLV obtained from persistently infected cell lines. Intramuscular administration of two vaccine doses (each containing 0.40 mg virus glycoprotein with adjuvant), 2 weeks apart, conferred protection against challenge infection with BLV on 18 of the 20 vaccinated calves. Two calves were not protected, in spite of their positive serologic response to vaccination. The results demonstrate the efficiency of the BL-VACC-RO vaccine in preventing BLV infection.