Surfactant replacement therapy: a multicentric trial comparing two dosage approaches

This is an interim analysis of a multicentric trial that took place in 7 Neonatal Units to compare two initial doses of exigenous pulmonary surfactant (100 mg/kg and 200 mg/kg of phospholipids)by using a porcine surfactant for the treatment of very severe Hyaline Membrane Disease. The initial higher dose produced better oxigenation of arterial blood, reducing the time in high oxygen concentrations,while retreatments were necessary in less than half of the infants receiving 200 mg/kg as initial dose. The protocol of this study allowed the administration of additional doses only when FiO(2) was equal or greater than 0.40 instead of > 0.21, as in a large study recently published, where the same initial doses were given. This resulted in more than 40% reduction in the amount of surfactant administered,with apparently similar clinical outcome.     

Age-Related Alterations in Antioxidant Enzymes, Lipid Peroxide Levels, and Somatosensory-Evoked Potentials: Effect of Sulfur Dioxide

The effect of sulfur dioxide (SO₂) on somatosensory-evoked potentials (SEPs), thiobarbituric acid reactive substances (TBARS), and the activities of Cu,Zn-superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were investigated in young (3 months), middle-age (12 months), and old (24 months) Swiss male albino rats. Ten ppm SO₂ was administrated to the animals of SO₂ groups in an exposure chamber for 1 h/day × 7 days/week × 6 while control groups were exposed to filtered air in the same condition. SO₂ exposure caused increased levels of brain Cu,Zn-SOD activity and decreased levels of brain GSH-Px activity in all experimental groups with respect to their corresponding control groups. Brain CAT activities were unaltered. Brain TBARS levels of all SO₂-exposed groups were significantly increased in comparison with their respective control groups. The mean latencies of P₁, P₂, and N₂ components in the older group were either significantly different from the young or from the middle-age groups. The mean latency of the N₁ component in the older group and that of P₁ and N₁ in the middle-age group were significantly increased compared with the young group. SO₂ exposure caused the prolongation of all components in the young group, whereas it affected only the P₂ component in the middle-age group, but it did not result in any latency change in the older group in comparison with their corresponding control groups. Received: 22 December 1998/Accepted: 7 April 1999     

Tuberculosis treatment adherence in Pelotas, Brazil, from the patient's perspective

This study deals with adherence to tuberculosis treatment among men and women as well as the disease's links and consequences vis-à-vis life styles and treatment outcomes. The ethnographic study was a component of the Tuberculosis Epidemiological Control Project in the city of Pelotas and aimed to identify the reasons patients failed to complete treatment. Direct ethnographic observations and semi-structured interviews were used. Use of the term "adherence" is justified by the concern for extending to other fundamental factors in addition to the patient's own individual responsibility. This approach fostered an understanding of views towards disease, social dynamics among the various protagonists involved in the disease process, and treatment. Some of the factors considered in adherence to treatment were: socio-demographic characteristics, cultural factors, popular beliefs, the cost-benefit relationship, physical and chemical aspects of the drugs, the physician-patient relationship, and level of family participation in treatment.     

Evidence that the nitrergic neurotransmitter and endothelium-derived relaxing factor might be S-nitrosothiols in the mouse corpus cavernosum

The effects of thimerosal, a sulfhydryl oxidizing agent on nitrergic, endothelium-dependent and -independent relaxations were investigated to examine the possibility that the nitrergic neurotransmitter and endothelium-derived relaxing factor (EDRF) could be S-nitrosothiol or free nitric oxide (NO) in the isolated mouse corpus cavernosum. Thimerosal (5 x 10(-6)-2 x 10(-5) M) inhibited or almost abolished electrical field stimulation--(EFS, 30V, 0.5 ms, 15 sec, 1, 2, 4, 8, 16 Hz), acetylcholine--(ACh, 5 x 10(-8)-1.25 x 10(-6) M), glyceryl trinitrate--(GTN, 3 x 10(-7)-3 x 10(-6) M), and S-nitrosoglutathione--(GSNO, 5 x 10(-6)-1.25 x 10(-4) M) induced relaxations. Thiomerosal inhibition seems to be specific to L-arginine NO pathways since it had no effect on acidified sodium nitrite--(10(-4)-5 x 10(-4) M), photoactivated sodium nitrite--(2 x 10(-4) M), isoprenaline--(10(-6) M), or papaverine--(10(-4) M) elicited relaxations. Moreover, the inhibitory effect of thimerosal on the nitrergic, ACh- or GTN-induced relaxations were partly reversed by sulfhydryl-containing compounds, L-cysteine (10(-3) M), dithiothreitol (10(-3) M), or glutathione (10(-3) M). However L-methionine (10(-3) M), which contains a methyl group on the sulphur atom, failed to restore the thimerosal inhibition. Thimerosal did not change the contraction produced by 10(-4) M NG-nitro-L-arginine methyl ester. These findings indicate that the nitrergic neurotransmitter as well as EDRF may not be free NO but NO-transferring molecules, probably S-nitrosothiols, in the mouse corpus cavernosum.     

Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes

To assess the responsiveness of the interrenal axis to stress, we injected toads exposed to coal combustion wastes and toads from an unpolluted reference site with adrenocorticotropic hormone (ACTH), as well as the vehicle alone (saline). Initial circulating levels of corticosterone in toads captured at the polluted area were significantly higher than levels in toads from the reference site. Corticosterone levels in toads from the polluted site remained high even after 2 weeks of laboratory acclimation and injection with saline. The results may suggest disruption of hepatic enzymes responsible for the metabolic clearance of steroid hormones. Injection of toads from the polluted site with ACTH had no effect on plasma corticosterone levels, whereas a similar treatment of toads from the reference site stimulated a marked increase in corticosterone. Our study provides evidence that toads exposed to coal combustion wastes may be less efficient at responding to additional environmental stressors.     

A study on impact and tensile strength of acrylic resin filled with short ultra-high molecular weight polyethylene fibers

In dentistry, acrylates have been used for preparing denture bases for 50 years. Although polymethylmethacrylates (PMMA) are known to be an ideal base material, they possess some undesirable mechanical properties, especially their impact strength and tensile strength, which appear to be unsatisfactory for some applications. Additives and fibers have therefore been used to enhance and improve these properties over the last two decades. The present article describes the mechanical properties, impact and tensile strength of PMMA reinforced with chopped ultra-high molecular weight polyethylene fiber (6 mm long). It was found that, although the processing involved for high loading of fibers into the PMMA was difficult, the resulting improvement of impact strength was substantial.     

Vaginal atresia and Bardet-Biedl syndrome association: a component or a distinct entity?

Bardet-Biedl syndrome is an autosomal recessive disorder. It is characterized by cardinal anomalies including retinal dystrophy, digital malformations, mental retardation, obesity, and hypogonadism. Recently, renal anomalies also are mentioned among the cardinal signs. Although association of genital anomalies among affected boys are well known, the association of vaginal atresia and other structural genital anomalies are not mentioned among the less-common manifestations of Bardet-Biedl syndrome in girls. Two girls with Bardet-Biedl syndrome presented with hematometrocolpos in the preadolescent period and vaginal atresia was diagnosed. After surgical treatment and extended hospitalization, uncontrolled sepsis resulted in progressive renal failure and death of both patients. Vaginal atresia is often delayed or missed in the early childhood period. In girls with Bardet-Biedl syndrome, vaginal atresia or other structural genital anomalies should be evaluated more systematically during the initial diagnosis of the syndrome. In infancy, the evaluation of a child with vaginal atresia also should include the differential diagnosis of Bardet-Biedl syndrome. Vaginal atresia may either form a component of the syndrome, or girls who present with vaginal atresia in addition to other components of Bardet-Biedl syndrome might form a distinct entity.     

Hemodynamic effects of medical antishock trousers during mechanical ventilation

Purpose

To compare the hemodynamic effects of medical antishock trousers (MAST) inflation in mechanically ventilated patients with normal and poor left ventricular function.

Methods

Twelve patients requiring respiratory support were divided into two groups according to baseline transesophageal echocardiography (TEE) measurements: normal left ventricular dimensions and fractional area of contraction (FAC=61 ± 5%) (n=7) and dilated cardiomyopathy with reduced FAC (21 ± 1%) (n=5). All patients were studied when two successive levels of load (mild load by inflation of the leg compartment of MAST at 50 cmH₂O and high load by adding the abdominal compartment of MAST inflated at 30 cmH₂O) were applied. Global left ventricular systolic function was assessed on the TEE transgastric short-axis view. End-systolic wall stress (ESWS) was used as an indicator of left ventricular afterload.

Results

Total respiratory, lung and chest wall compliances were reduced by 48%, 51% and 27% respectively at the high load level (P < 0.05). Whereas no hemodynamic changes occurred at mild load, the high load level produced an increase in left ventricular afterload as evidenced by concomitant increases in diastolic arterial blood pressure (66 ± 6 to 79 ± 6 mmHg,P < 0.05) and ESWS (69 ± 12 to 74 ± 12 Kdyn·cm^?2·m^?2,P < 0.05). In patients with dilated cardiomyopathy, this increase in afterload impaired the left ventricular systolic function and end-systolic area increased (19.0 ± 2.5 to 21.4 ± 2.9 cm²·m^?2,P < 0.05) while FAC decreased (22 ± 2 to 16 ± 2%,P < 0.05). Left ventricular end-diastolic area remained unchanged during the study in both groups.

Conclusion

MAST inflation impairs respiratory mechanics and global left ventricular systolic function in cardiac patients without changes in left ventricular preload.