Impact of an aggressive surgical approach on surgical outcome in type A aortic dissection

BACKGROUND: To evaluate the impact of an aggressive surgical approach on early and late outcome in type A aortic dissection. METHODS: From 1983 to 2001, 240 patients underwent operation for acute (n = 138) and chronic (n = 102) type A aortic dissection. The extent of distal aortic resection included the ascending aorta in 39 (16%) patients, hemiarch (HAR) in 47 (20%), and total arch (TAR) in 154 (64%), including 19 patients who also had their descending aorta replaced (DAR). RESULTS: The in-hospital mortality did not differ between TAR with or without DAR and other more conservative techniques (12.3% versus 16.3%). Actuarial survival at 10 years including in-hospital mortality was 72.4% +/- 3.3% and freedom from reoperation was 77.2% +/- 3.6% for all patients: neither was influenced by the extent of distal aortic resection or acuity of aortic dissection. Multivariate analysis revealed younger age and failure to resect the intimal tear to be independent determinants for late reoperation. However, in contrast to 22 patients who had more conservative operations, none of the patients with TAR required reoperation on the aortic arch through a sternotomy incision. CONCLUSIONS: An aggressive surgical approach did not adversely influence early and late survival following type A aortic dissection; it reduced the necessity of late reoperation and facilitated distal aortic reoperation.     

Electrodiagnostic approach to the patient with suspected mononeuropathy of the lower extremity

Lower extremity mononeuropathies are less common than those affecting the upper limb. Yet, they are often challenging and more difficult to diagnose. The electrodiagnostic (EDX) studies play a pivotal role in diagnosis. Well planned and executed studies are very useful, although limiting factors such as age, foot swelling or prior lumbar spine surgery may hinder making a definite diagnosis. In this section, the author emphasizes the EDX studies of most lower extremity mononeuropathies and discusses, briefly, their anatomical and clinical aspects.     

Modeling and characterization of a nanoliter drug-delivery MEMS micropump with circular bossed membrane

A MEMS (micro-electro-mechanical systems) micropump with circular bossed membrane designed for nanoliter drug delivery is characterized in this article. A quasistatic model under consideration of low operating frequency is used to characterize this micropump. The mathematical model is an ordinary differential equation that describes the behavior of the micropump by including its key components of bossed membrane and inlet/outlet microvalves. Characterizations of bossed membrane and microvalves are carried out separately in the finite element analysis ANSYS package. The stroke volume of the membrane is calculated within the range that the linear deflection theory is valid. Analysis of the microvalve is a challenging task in microfluidics because it is a coupled field (solid-fluid coupling) problem. To solve the structural (solid) or fluid part separately is impractical in characterizing drug-delivery micropumps. Based on sequential weak solid-fluid coupling in ANSYS/FLOTRAN, the flow rates across the inlet and outlet microvalves are analyzed and simulated. Because the quasistatic equation contains several nonlinear terms, closed-form analytical solution for this equation is impossible; thus MATLAB is used to solve it numerically. The transient flow rate of the micropump is obtained by substituting the pressure in microchamber into the flow rate function of outlet microvalves. Integration of the function over 1 driving cycle and multiplication by the driving frequency provides the drug-delivery rate of the micropump.     

Adult polyglucosan body disease: a case report of a manifesting heterozygote

A 62-year-old man developed progressive gait instability, bladder dysfunction, proximal weakness, distal sensory loss, and mild cognitive impairment over 6 years. Neurologic examination revealed upper and lower motor neuron dysfunction in the lower extremities, with distal sensory loss. Electrodiagnostic studies, magnetic resonance imaging of the brain, and sural nerve biopsy were consistent with adult polyglucosan body disease. Biochemical and genetic analyses demonstrated reduced glycogen brancher enzyme levels associated with a heterozygous point mutation (Tyr329Ser or Y329S) in the glycogen brancher enzyme gene on chromosome 3. Mutational heterozygosity in the glycogen brancher enzyme gene has not been previously reported as a cause for this rare disease. A review of the clinical presentation, pathogenesis, etiology, and diagnosis of this disease is presented.     

Chronic hepatitis C treatment. Side effects and their management

The current standard of treatment of chronic hepatitis C infection is the combination therapy of pegylated interferon plus ribavirin for 48 weeks for genotype 1 and 4 and 24 weeks for genotype 2 and 3. Side effects such as influenza-like syndrome, gastrointestinal, neuropsychiatric, dermatological and endocrinological symptoms are not uncommon. Laboratory abnormalities such as hematological and biochemical may be frequent. These side effects are compatible with treatment continuation if symptoms are managed carefully. The adverse effects are dose dependent and often reversible. Premature withdrawal rates can be reduced if side effects are identified early. It is, however, pertinent to target treatment to early responders and avoid side effects in patients who have low predictive response to treatment.     

Mirtazapine-induced serotonin syndrome

An 85-year-old woman developed sudden confusion and dysarthria progressing to mutism, orobuccal dyskinesias, generalized tremors worse with activity, ataxia, and rigidity with cog wheeling without high-grade fevers or dysautonomia. These findings were related temporally to the institution of mirtazapine as monotherapy for a major depressive illness with superimposed anxiety disorder. Withdrawal of the agent resulted in early notable clinical resolution with only residual hypertonia after 2 weeks. This is a rare report of serotonin syndrome induced by mirtazapine monotherapy. The hypothesized pathophysiologic mechanism in this case is overstimulation of serotonin (5-hydroxytryptamine or 5-HT) type 1A receptors (5-HT(1A)) in the brainstem and spinal cord in an individual with risk factors for hyperserotoninemia resulting from reduced, acquired endogenous serotonin metabolism.     

Place of Video-thoracoscopy in Thoracic Surgical Practice

The advent of video-endoscopy revolutionizes the practice of surgery. Within a short span of time, video-assisted thoracic surgery (VATS) has become an acceptable approach to a wide range of thoracic procedures. The use of VATS as a diagnostic modality is now well established. For therapeutic procedures, VATS has also been generally accepted for the treatment of such conditions as primary spontaneous pneumothorax, loculated effusions, thoracodorsal sympathectomy, and resection of simple mediastinal cysts. Its roles in more complex procedures such as thymectomy and anatomic lung resections, however, remain poorly defined at present, even though the existing intermediate-term results are encouraging. VATS is still in evolution. Miniaturization of instruments promises to reduce access-induced trauma even further. On the other hand, attention to cost-containment is essential if VATS is to be applicable to patients in developing countries. Technology will continue to change. Carefully conducted clinical trials should precede the general acceptance of any new technology, no matter how attractive it may appear initially.     

Respiratory involvements among women exposed to the smoke of traditional biomass fuel and gas fuel in a district of Bangladesh

Objectives

Burning of biomass fuel (cow-dung, crop residue, dried leaves, wood, etc.) in the kitchen releases smoke, which may impair the respiratory functions of women cooking there. This paper aimed to compare the respiratory symptoms between biomass fuel users and gas fuel users in Bangladesh.

Methods

A cross-sectional survey was conducted through face-to-face interviews and chest examination of 224 adult women using biomass fuel in a rural village and 196 adult women using gas fuel in an urban area.

Results

The prevalence of respiratory involvement (at least one among nine symptoms and two diseases) was significantly higher among biomass users than among gas users (29.9 vs. 11.2 %). After adjustment for potential confounders by a logistic model, the odds ratio (OR) of the biomass users for the respiratory involvement was significantly higher (OR = 3.23, 95 % confidence interval 1.30–8.01). The biomass fuel use elevated symptoms/diseases significantly; the adjusted OR was 3.04 for morning cough, 7.41 for nasal allergy, and 5.94 for chronic bronchitis. The mean peak expiratory flow rate of biomass users (253.83 l/min) was significantly lower than that of gas users (282.37 l/min).

Conclusions

The study shows significant association between biomass fuel use and respiratory involvement among rural women in Bangladesh, although the potential confounding of urban/rural residency could not be ruled out in the analysis. The use of smoke-free stoves and adequate ventilation along with health education to the rural population to increase awareness about the health effects of indoor biomass fuel use might have roles to prevent these involvements.