Acute aortic dissection: association with patent ductus arteriosus

The Cuban recombinant vaccine against the hepatitis B virus was applied to a group of individuals over 65 from a geriatric home in Havana City. Dose of 20 ìg were administered within a scheme from 0.1 to 6 months in order to study its immunogenicity, which was evaluated at 2, 7, and 12 months after the first dose. 47.1% of protective titres and geometrical mean of 6.04 UI/L were obtained after 60 days. 100% of seroconversion (UI/L) and seroprotection (10 UI/L) and geometric mean of 136.93 UI/L were obtained when the immune response was evaluated on the 7th month. Finally, after a year, seroconversion and seroprotection were also of 100%, and the geometric mean was of 204.61 UI/L. It was proved the high immunogenic power of this vaccine, which makes it recommendable to protect this age group from the hepatitis B virus.     

Effects of high oxygen concentrations on microbial biosensor signals. Hyperoxygenation by means of perfluorodecalin

Amperometric biosensors register oxygen depletion in response to analyte catabolism, and thus are limited by the availability of dissolved oxygen. Microbial sensors containing immobilized cells of Gluconobacter oxydans were hyperoxygenated to 400% of control levels and the effects on sensor responses to glucose were determined. Oxygenated perfluorodecalin (a completely fluorinated organic substance) was as effective in hyperoxygenation as direct sparging with O2, increasing sensor base medium oxygen concentrations from 9.3 to 37 mg/l. Hyperoxygenation enhanced maximal biosensor response amplitudes, particularly at high cell loading densities. Maximal response rates were also improved, although less dramatically. Results suggest that hyperoxygenation may be a new general approach for modulating biosensor responses.     

Diffusion of monomers from bonding resin-resin composite combinations through dentine in vitro

OBJECTIVES: Previous work has demonstrated diffusion of the monomer triethylene glycol dimethacrylate (TEGDMA) from resin composite through dentine in vitro. The objective of the present work was to examine monomer diffusion from bonding resins and resin composites used in combination. METHODS: Occlusal cavities were prepared in tooth crowns and restored with bonding resin-resin composite combinations. Aqueous samples from the 'pulpal chamber' of each tooth were removed at timed intervals for analysis by reversed phase-high performance liquid chromatography and mass spectrometry. RESULTS: Bonding resins contributed to monomer diffusion. A TEDGMA-containing bonding resin used in combination with a TEGDMA-containing resin composite hastened and increased TEGDMA diffusion through dentine. A 2-hydroxyethyl methacrylate (HEMA)-containing bonding resin used in combination with a TEGDMA-containing resin composite reduced TEGDMA diffusion only slightly compared with the resin composite alone and added substantial diffusion of HEMA. CONCLUSION: The bonding resins tested contributed to monomer passage to the pulp space and did not prevent movement of monomer from resin composites to the pulp.     

A history of M.S. and Ph.D. programs offered by schools and colleges of optometry in North America

This paper gives an overview of the history of M.S. and Ph.D. graduate programs offered by schools and colleges of optometry. It also highlights some of the contributions of Henry Hofstetter to graduate education.     

Maximum cardiac output during incremental exercise by first-pass radionuclide ventriculography

A flow injection hydride atomic absorption spectrometric (FI-HAAS) method was developed for determining selenium in human milk and whole blood after microwave digestion of the sample. The sample (2 mL human milk or 0.25 mL blood) was introduced into the microwave vessel with 1.5 mL HNO3 and 0.25 mL H2O2 and 300 W (4 min) and 600 W (4 min) were applied. The digestion was completed by heating to 140 degrees C (2-3 h). Se (VI) was reduced to Se (IV) with hydrochloric acid. The instrumental conditions for FI-HAAS (concentrations of reducing agent and carrier acid, flow rate of argon carrier gas, and sample volume injected) were optimized. The detection limit of the proposed method was 0.23 ng/mL (assay) or 115 pg Se (absolute) in biological samples (1.15 ng/mL milk, 10.4 ng/mL blood). The precision values were 5.0% for milk and 4.0% for blood. The accuracy was evaluated with 2 reference materials, National Institute of Standards and Technology Non-Fat Milk Powder (found: 104.3 +/- 7.2 ng/g, certified: 110 +/- 10 ng/g) and Whole Blood Seronorm (found: 81 +/- 7.3 ng/mL, reference: 83 +/- 4 ng/mL). The results show the suitability of the method for selenium determination in human milk and whole blood. The method was applied to whole blood samples obtained from pregnant women and to human milk.     

Intraocular pressure fluctuations during scleral buckling surgery

PURPOSE: The purposes of this study are to measure real-time intraocular pressure (IOP) during scleral buckling and to determine the effects of elevated IOPs on ocular perfusion. PATIENTS AND METHODS: A standard 4-mm, 20-gauge infusion cannula was inserted through the pars plana, connected to a standard hemodynamic monitoring unit with an electronic pressure transducer, and calibrated. The authors measured real-time IOP in 20 eyes undergoing scleral buckling surgery for primary rhegmatogenous retinal detachments and determined the IOP required to close the central retinal artery. Pressure measurements were read from the monitor videoscreen intraoperatively and from a continuous paper tracing postoperatively. RESULTS: The patients ranged in age from 24 to 88 years (mean, 59.7 years). The highest IOP elevations occurred during scleral depression and cryopexy, ranging up to 210 mmHg (mean, 116 mmHg). Pressures at which the central retinal artery closed ranged from 48 to 110 mmHg (mean, 79.2 mmHg). Manipulations of the globes caused IOPs greater than the central retinal artery perfusion pressures in 13 of the 20 patients. The duration of pressures in excess of the central retinal artery perfusion pressure ranged from 6 to 402 seconds (mean, 118.8 seconds). There were no intraoperative or postoperative complications from the infusion cannula. CONCLUSIONS: Conventional scleral buckling surgery causes wide fluctuations in IOP and may impair ocular perfusion. Additional studies are needed to determine the long-term consequences of these pressure elevations.     

Herd immunity to filarial infection is a function of vector biting rate

Despite the existence of an impressive body of work on human immune responses against filarial infections, the occurrence of a protective response to infection remains unclear. Here, we use a combined modelling and comparative data analysis framework to address this issue for human infections with the filarial parasite, Wuchereria bancrofti. By analogy with previous work, the analysis involves the comparison of observed field patterns of infection with epidemiological patterns predicted by a mathematical model of parasite immunity. Unlike most other human helminths, which are transmitted by ingestion or dermal penetration, exposure to infection with lymphatic filariasis can be measured explicitly in terms of vector mosquito biting rates, thereby also allowing, probably for the first time, examination of the suggested role of exposure in generating herd immunity to macroparasites. Observed field patterns in this study were derived from 19 different published studies, which gave parallel estimates of community exposure rates and the corresponding age--prevalence patterns of infection, while predictions of the epidemiological impact of herd immunity were obtained using a catalytic model framework. The results provide the first conclusive evidence to date that variations in the observed age--prevalence patterns of infection in filariasis can be effectively explained by the occurrence of an exposure-driven acquisition of herd immunity. We discuss this result in terms of implications for the new World Health Organization-led initiative for the global control of this parasitic disease.