Adeno-associated virus for cystic fibrosis gene therapy

Gene therapy is an alternative treatment for genetic lung disease, especially monogenic disorders such as cystic fibrosis. Cystic fibrosis is a severe autosomal recessive disease affecting one in 2500 live births in the white population, caused by mutation of the cystic fibrosis transmembrane conductance regulator (CFTR). The disease is classically characterized by pancreatic enzyme insufficiency, an increased concentration of chloride in sweat, and varying severity of chronic obstructive lung disease. Currently, the greatest challenge for gene therapy is finding an ideal vector to deliver the transgene (CFTR) to the affected organ (lung). Adeno-associated virus is the most promising viral vector system for the treatment of respiratory disease because it has natural tropism for airway epithelial cells and does not cause any human disease. This review focuses on the basic properties of adeno-associated virus and its use as a vector for cystic fibrosis gene therapy.

Biphasic modulation of insulin receptor substrate-1 during goitrogenesis

Insulin receptor substrate-1 (IRS-1) is the main intracellular substrate for both insulin and insulin-like growth factor I (IGF-I) receptors and is critical for cell mitogenesis. Thyrotropin is able to induce thyroid cell proliferation through the cyclic AMP intracellular cascade; however, the presence of either insulin or IGF-I is required for the mitogenic effect of thyroid-stimulating hormone (TSH) to occur. The aim of the present study was to determine whether thyroid IRS-1 content is modulated by TSH in vivo. Strikingly, hypothyroid goitrous rats, which have chronically high serum TSH levels (control, C = 2.31 ± 0.28; methimazole (MMI) 21d = 51.02 ± 6.02 ng/mL, N = 12 rats), when treated with 0.03 percent MMI in drinking water for 21 days, showed significantly reduced thyroid IRS-1 mRNA content. Since goiter was already established in these animals by MMI for 21 days, we also evaluated IRS-1 expression during goitrogenesis. Animals treated with MMI for different periods of time showed a progressive increase in thyroid weight (C = 22.18 ± 1.21; MMI 5d = 32.83 ± 1.48; MMI 7d = 31.1 ± 3.25; MMI 10d = 33.8 ± 1.25; MMI 14d = 45.5 ± 2.56; MMI 18d = 53.0 ± 3.01; MMI 21d = 61.9 ± 3.92 mg, N = 9-15 animals per group) and serum TSH levels (C = 1.57 ± 0.2; MMI 5d = 9.95 ± 0.74; MMI 7d = 10.38 ± 0.84; MMI 10d = 17.72 ± 1.47; MMI 14d = 25.65 ± 1.23; MMI 18d = 35.38 ± 3.69; MMI 21d = 31.3 ± 2.7 ng/mL, N = 9-15 animals per group). Thyroid IRS-1 mRNA expression increased progressively during goitrogenesis, being significantly higher by the 14th day of MMI treatment, and then started to decline, reaching the lowest values by the 21st day, when a significant reduction was detected. In the liver of these animals, however, a significant decrease of IRS-1 mRNA was detected after 14 days of MMI treatment, a mechanism probably involved in the insulin resistance that occurs in hypothyroidism. The increase in IRS-1 expression during goitrogenesis may represent...

Understanding the mechanisms of lung mechanical stress

Physical forces affect both the function and phenotype of cells in the lung. Bronchial, alveolar, and other parenchymal cells, as well as fibroblasts and macrophages, are normally subjected to a variety of passive and active mechanical forces associated with lung inflation and vascular perfusion as a result of the dynamic nature of lung function. These forces include changes in stress (force per unit area) or strain (any forced change in length in relation to the initial length) and shear stress (the stress component parallel to a given surface). The responses of cells to mechanical forces are the result of the cell's ability to sense and transduce these stimuli into intracellular signaling pathways able to communicate the information to its interior. This review will focus on the modulation of intracellular pathways by lung mechanical forces and the intercellular signaling. A better understanding of the mechanisms by which lung cells transduce physical forces into biochemical and biological signals is of key importance for identifying targets for the treatment and prevention of physical force-related disorders.

Functional changes of human quadriceps muscle injured by eccentric exercise

The present study evaluated functional changes of quadriceps muscle after injury induced by eccentric exercise. Maximal isometric torque of quadriceps and the surface electromyography (root mean square, RMS, and median frequency, MDF) of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles were examined before, immediately after and during the first 7 days after injury. Serum creatine kinase (CK) levels and magnetic resonance imaging (MRI) were used to identify muscle injury. The subject was used as her own control and percent refers to pre-injury data. Experiments were carried out with a sedentary 23-year-old female. Injury was induced by 4 bouts of 15 maximal isokinetic eccentric contractions (angular velocity of 5º/s; range of motion from 40º to 110º of knee flexion). The isometric torque of the quadriceps (knee at 90º flexion) decreased 52 percent immediately after eccentric exercise and recovered on the 5th day. The highest reduction of RMS occurred on the 2nd day after injury in both VL (63 percent) and VMO (66 percent) and only VL recovered to the pre-injury level on the 7th day. Immediately after injury, the MDF decreased by 5 and 3 percent (VMO and VL, respectively) and recovered one day later. Serum CK levels increased by 109 percent on the 2nd day and were still increased by 32 percent on the 7th day. MRI showed large areas of injury especially in the deep region of quadriceps. In conclusion, eccentric exercise decreased the isometric torque and electromyographic signals of quadriceps muscle, which were recovered in one week, despite the muscle regeneration signals

ClC-5 chloride channel and kidney stones: what is the link?

Nephrolithiasis is one of the most common diseases in the Western world. The disease manifests itself with intensive pain, sporadic infections, and, sometimes, renal failure. The symptoms are due to the appearance of urinary stones (calculi) which are formed mainly by calcium salts. These calcium salts precipitate in the renal papillae and/or within the collecting ducts. Inherited forms of nephrolithiasis related to chromosome X (X-linked hypercalciuric nephrolithiasis or XLN) have been recently described. Hypercalciuria, nephrocalcinosis, and male predominance are the major characteristics of these diseases. The gene responsible for the XLN forms of kidney stones was cloned and characterized as a chloride channel called ClC-5. The ClC-5 chloride channel belongs to a superfamily of voltage-gated chloride channels, whose physiological roles are not completely understood. The objective of the present review is to identify recent advances in the molecular pathology of nephrolithiasis, with emphasis on XLN. We also try to establish a link between a chloride channel like ClC-5, hypercalciuria, failure in urine acidification and protein endocytosis, which could explain the symptoms exhibited by XLN patients

Structure and function of the cystic fibrosis transmembrane conductance regulator

Cystic fibrosis (CF) is a lethal autosomal recessive genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR). Mutations in the CFTR gene may result in a defective processing of its protein and alter the function and regulation of this channel. Mutations are associated with different symptoms, including pancreatic insufficiency, bile duct obstruction, infertility in males, high sweat Cl-, intestinal obstruction, nasal polyp formation, chronic sinusitis, mucus dehydration, and chronic Pseudomonas aeruginosa and Staphylococcus aureus lung infection, responsible for 90 percent of the mortality of CF patients. The gene responsible for the cellular defect in CF was cloned in 1989 and its protein product CFTR is activated by an increase of intracellular cAMP. The CFTR contains two membrane domains, each with six transmembrane domain segments, two nucleotide-binding domains (NBDs), and a cytoplasmic domain. In this review we discuss the studies that have correlated the role of each CFTR domain in the protein function as a chloride channel and as a regulator of the outwardly rectifying Cl- channels (ORCCs)

Predicting the donor liver lobe weight from body weiht for split-liver transplantation

It is possible to obtain two good-quality hepatic transplants from a single cadaveric liver by separation of the right and left lobes of the liver. We attempted to define a relationship based only on donor body weight for predicting donor total liver weight as well as donor right (segments V-VIII) and left (segments II-IV) hepatic lobe weight. Segment I (caudate lobe) is resected and thus lost in this procedure. The study was performed on 60 human cadaveric livers. We correlated cadaveric body weight (mean + or - SD), 72.43 + or - 9.54 kg, with total liver weigh, 1.54 + or - 0.36 kg, and right and left lobe weight, 0.88 + or - 0.23 kg and 0.65 + or - 0.17 kg, respectively, with total liver weight. A formula was obtained by linear regression which provided the following relationships: total liver weight (g) = [245.57 + 17.92 x (body weight, kg)]; right lobe weight (g) = [67.58 + 0.52 x(total liver weight, g)]. The selection of the recipient on the liver transplant waiting list can be made on the basis of these relationships

Estudio clínico morfológico en las infecciones ginecológicas por Chlamydia trachomatis / Clinico morphological study in ginecologic infections by Chlamydia trachomatis

Cincuenta y dos pacientes de la consulta de triaje del Servicio de Ginecología del Hospital Vargas, Caracas, con frotis citológicos en los que se encontraron células con inclusiones características de Chlamydia trachomatis, fueron tratadas junto con su pareja con doxiciclina (Vibramicina) 100 mg dos veces al día por 21 días. Finalizado el tratamiento regresaron a control 27 pacientes, que fueron evaluados clínicamente; se les realizó colposcopia y nuevo examen citológico, comparándolo con la primera muestra. Los resultados indicaron que en 20 casos (74%) el frotis se negativizó y se modificó el exudado inflamatorio; en 4 casos (15%) los frotis resultaron dudosos y en 3 casos (11%) no se apreció diferencia alguna con la primera citología. Clínicamente, hubo también remisión de los síntomas en aquellos casos que presentaron inicialmente sintomatología. Estos resultados muestran una buena correlación clínico-citológica, lo que permite considerar al estudio citomorfológico con coloración de Papanicolaou como un examen útil para el diagnóstico de C. trachomatis, en grupos grandes de población que acuden a las consultas de Ginecología de nuestros hospitales, y que además no recarga económicamente a la institución, ya que este examen se realiza de rutina para la pesquisa de lesiones neoplásicas en cuello uterino