Formulation, pharmacokinetics and biodistribution of Ofloxacin-loaded albumin microparticles and nanoparticles.

Albumin microparticles containing Ofloxacin (Fluoroquinolone derivative commonly used in hospitals) were formulated by the spray dry method. By decreasing the pump feed rate or the total polymer concentration, a mixture of albumin/hypromellose acetate succinate (HPMCAS) microparticles and nanoparticles (MP/NP), containing Ofloxacin, were formulated. MP/NP were characterized, in vitro (particle size, zeta potential, and encapsulation efficiency). A comparison of the pharmacokinetics and biodistribution of aqueous Ofloxacin and Ofloxacin-loaded MP/NP, in Balb/c mice, revealed that peak concentrations were reduced in the serum, liver, spleen and brain, and a more sustained release was observed in serum and all of the organs tested for Ofloxacin MP/NP, compared to aqueous Ofloxacin. The MP/NP formulation allowed extended release by 24 h in the liver and more than 48 h in the brain. In serum, the elimination rate of Ofloxacin MP/NP is slower, the half life is longer, area under the plasma concentration time curve is decreased and volume of distribution is increased.

Biofilm formation and effect of caspofungin on biofilm structure of Candida species bloodstream isolates.

Candida biofilms are microbial communities, embedded in a polymeric matrix, growing attached to a surface, and are highly recalcitrant to antimicrobial therapy. These biofilms exhibit enhanced resistance against most antifungal agents except echinocandins and lipid formulations of amphotericin B. In this study, biofilm formation by different Candida species, particularly Candida albicans, C. tropicalis, and C. parapsilosis, was evaluated, and the effect of caspofungin (CAS) was assessed using a clinically relevant in vitro model system. CAS displayed in vitro activity against C. albicans and C. tropicalis cells within biofilms. Biofilm formation was evaluated after 48 h of antifungal drug exposure, and the effects of CAS on preformed Candida species biofilms were visualized using scanning electron microscopy (SEM). Several species-specific differences in the cellular morphologies associated with biofilms were observed. Our results confirmed the presence of paradoxical growth (PG) in C. albicans and C. tropicalis biofilms in the presence of high CAS concentrations. These findings were also confirmed by SEM analysis and were associated with the metabolic activity obtained by biofilm susceptibility testing. Importantly, these results suggest that the presence of atypical, enlarged, conical cells could be associated with PG and with tolerant cells in Candida species biofilm populations. The clinical implications of these findings are still unknown.

The changing face of neurological rehabilitation

INTRODUÇÃO: A reabilitação neurológica e a contribuição da fisioterapia mudaram consideravelmente nas últimas décadas, uma vez que o desenvolvimento científico e tecnológico permitiu uma maior compreensão dos mecanismos de reorganização cerebral e dos mecanismos envolvidos no controle e desempenho motores, em suas dificuldades e adaptações. OBJETIVO: Este artigo apresenta uma perspectiva histórica da segunda metade do século passado. DISCUSSÃO: Pesquisas científicas atuais e a subseqüente reavaliação do efeito funcional dos problemas que aparecem pela lesão do neurônio motor superior estão levando à mudança de foco das intervenções clínicas, com ênfase na otimização motora através de exercícios de tarefas orientadas, de ganho de força e de treino de desempenho físico. Achados em modelos animais e humanos sugerem que, para que a reabilitação seja eficiente em otimizar a reorganização neural e a recuperação funcional, uma ênfase maior deve ser colocada em tarefas úteis que sejam desafios interessantes com um treino que promove o aprendizado. As questões da intensidade do treino de tarefas e da extensão do estresse cardiovascular durante a atividade física também são discutidos. Embora exista muito que se aprender em achados de pesquisa clínica, a prática clínica da reabilitação continua ser altamente variada, dependendo largamente do método preferido pelo terapeuta individual, e com predomínio dos métodos terapêuticos desenvolvidos meio século atrás. Fisioterapeutas necessitam assumir a responsabilidade do uso de técnicas baseadas em evidências, ou pelo menos usar métodos de intervenção e medidas objetivas de resultados que sejam cientificamente aceitáveis.

Protocol for detection of biofilms on needleless connectors attached to central venous catheters.

Central venous catheter needleless connectors (NCs) have been shown to develop microbial contamination. A protocol was developed for the collection, processing, and examination of NCs to detect and measure biofilms on these devices. Sixty-three percent of 24 NCs collected from a bone marrow transplant center contained biofilms comprised primarily of coagulase-negative staphylococci.

Inter-segmental co-ordination in sit-to-stand: an age cross-sectional study.

BACKGROUND AND PURPOSE: Being able to sit-to-stand (STS) effectively is an important functional skill, but there is little information available on the changes that occur with growth and maturity. This study aimed to investigate the inter-segmental co-ordination of STS in three different age groups (12-18 months, 4-5 years and 9-10 years). METHOD: The children studied wore reflective markers and were videotaped as they stood up from a height-adjustable seat that straddled a forceplate. Segmental kinematics and vertical ground reaction force were determined from the co-ordinate and forceplate data. RESULTS: Even at the earliest developmental stage the children had mastered the basic inter-segmental pattern observed in adults. The youngest children, however, were not able to end the movement in quiet standing; rather they raised up on their toes or took a step forward. Performance varied both within and between subjects. Although there was a similarity in the motor pattern used by the younger subjects to that of the older subjects, developmental trends were evident on the videotapes and on examination of the kinematic and kinetic variables. Movement time, amplitude and peak angular velocity of trunk flexion increased with age. Whereas the children in the older age groups displayed a pattern of vertical ground reaction force similar to that reported for adults, the youngest children tended to reach peak force gradually, often with fluctuations. Although there were characteristic trajectories in the phase-plane plots for each group, the overall trend was for the percentage of smooth plots representing a co-ordinated movement, to increase with age. CONCLUSIONS: Differences in inter-segmental co-ordination between the ages studied may relate to the child's ability to control horizontal momentum and to balance.

Muscle synergies and joint linkages in sit-to-stand under two initial foot positions.

OBJECTIVE: The purpose of this study was to investigate the activation pattern of six lower limb muscles during standing up from two initial foot positions and to examine relationships between the onsets of muscle activity and the dynamics of the action. In contrast to earlier studies, an algorithm was used to measure onsets and duration of muscle activity. METHOD: The activity of biceps femoris, rectus femoris, vastus lateralis, tibialis anterior, lateral gastrocnemius and medial soleus was studied as nine male subjects between the ages of 20 and 35 stood up from two initial foot positions (foot forward, foot back). Subjects sat on a height-adjustable seat with their right foot on a force platform and were videotaped as they stood up. RESULTS: When the feet were forward there were significant increases in movement duration, displacement and velocity of trunk segment flexion at the hips reflecting the increased distance the body mass must be moved forward. The sequence of onsets and the duration of muscle activity, however, were consistent across the two conditions. Onsets of extension at hip, knee and ankle, however, correlated with different muscle activity depending on the foot position. CONCLUSION: The results suggest that muscles working over different joints are temporally linked and that different muscle linkages may be utilised in the lower limb to coordinate the sit-to-stand action under different functional demands.

Muscle length effect on the pendulum test.

OBJECTIVE: An investigation of the effect of the length of knee extensor muscles on the pendulum test. DESIGN: Descriptive. Statistical analysis utilized analysis of variance with planned comparisons. SETTING: Community clubs and a stroke rehabilitation unit. PARTICIPANTS: Twenty subjects aged 54 to 83 yrs, more than 6 weeks after stroke, and 31 healthy subjects aged 60 to 79 yrs. OUTCOME MEASURES: Two tests: pendulum test and knee extensor muscle length test. RESULTS: For both affected and intact legs, stroke subjects had significantly smaller angle of reversal (p < .001), peak angular velocity (p < .001), and maximum passive knee flexion (p < .001) than healthy subjects. When angle of reversal was normalized for passive knee flexion, there were no significant differences between healthy and stroke subjects. There were no significant differences in any variable between the intact and affected legs of the stroke subjects. CONCLUSION: Soft tissue changes, rather than hyperreflexia, may explain the decreased angle of reversal and peak angular velocity in the stroke subjects studied.

Susceptibility of vancomycin-resistant enterococci to environmental disinfectants.

OBJECTIVE: To determine the susceptibilities of vancomycin-resistant and -sensitive enterococci (VRE and VSE) to various concentrations of commonly used, commercial, hospital-grade disinfectants. DESIGN: A microbial suspension test using inocula of 10(8) cells per mL in a disinfectant test dilution was used to determine inactivation kinetics of the test strains. In each test, 1-mL aliquots were removed from the cell-disinfectant mixtures at 15 and 30 seconds and then at 1-minute intervals for 5 minutes and neutralized. Appropriate serial dilutions were plated on agar medium for enumeration of survivors. RESULTS: VRE and VSE challenge inocula (in the absence of any additional protein or serum challenge) were below the limit of detection (5 colony-forming units/mL) after 15 seconds' exposure to the manufacturers' suggested use-dilutions of quaternary ammonium, phenolic, or iodophor germicidal detergents. In subsequent tests, when the disinfectants were diluted far beyond-the recommended use-dilutions (extended dilution), no differences were demonstrated between the susceptibilities of VRE and VSE. CONCLUSIONS: VRE and VSE are sensitive to a spectrum of commonly used environmental disinfectants and have parallel inactivation rates when challenged with extended dilutions of these products. Our findings did not demonstrate a relationship between antibiotic and germicide resistance. Routine disinfection and housekeeping protocols presently used in hospitals need not be altered due to concerns about the potential for environmentally mediated transmission of antibiotic-resistant microorganisms.

Comparison of chemical dehydration and critical point drying for the stabilization and visualization of aging biofilm present on interior surfaces of PVC distribution pipe.

In this study, fixation of attached glycocalyx on the interior surfaces of polyvinyl chloride distribution pipe remnants was compared with and without ruthenium red/osmium tetroxide and, in the final preparatory phase, with chemical dehydration and critical point drying. SEM examination of interior surface of the polyvinyl chloride pipe showed varying concentrations of adherent bacteria, depending on the preparatory technique used. It was concluded that using a combination of ruthenium red/osmium tetroxide and critical point drying is the optimum method for visually demonstrating aging biofilm on the interior surface of contaminated polyvinyl chloride pipe.

The colonization of solid PVC surfaces and the acquisition of resistance to germicides by water micro-organisms.

Six common water bacteria were examined for their ability to colonize polyvinyl chloride (PVC) surfaces, survive various germicidal treatment, and re-establish themselves in sterile distilled water (SDW). For each test, two 30.4 cm PVC pipes attached to a 90 degrees PVC elbow were filled with 600 ml of distilled water inoculated with either Pseudomonas aeruginosa, Ps. cepacia, Ps. mesophilica, Acinetobacter anitratus, Mycobacterium chelonae or M. chelonae var. abscessus. After 8 weeks contaminated water was removed and the pipes were exposed to 600 ml of 1:213 iodophor disinfectant (ID), 1:128 phenolic detergent (P), 1:256 quaternary ammonium compound (QA), stock iodophor antiseptic (IA), 2% formaldehyde (F), 10-15 ppm free chlorine (C), 2% glutaraldehyde (G) and 70% ethanol (E). These germicides were periodically sampled, neutralized and examined for surviving organisms. After exposure for 7 d the germicides were removed and each pipe was refilled with SDW. This was assayed at 7 d intervals to determine microbial re-establishment. Samples were removed during microbial conditioning and examined by scanning electron microscopy (SEM). Pseudomonads were isolated directly from ID, QA, C, P and F, and mycobacteria from QA, IA, ID, P, G, C and F. Pseudomonas aeruginosa and Ps. cepacia survived in PVC pipes after 7 d of exposure to P, ID and C; Ps. mesophilica, after C and ID; and both mycobacteria, after C. SEM examination of PVC remnants revealed bacterial attachment and formation of extracellular material with embedded cells. These studies show that common water bacteria can attach and colonize the interior surface of PVC pipes and develop significant resistance to the action of certain germicides.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a novel Rochalimaea species, R. henselae sp. nov., isolated from blood of a febrile, human immunodeficiency virus-positive patient.

Isolation of a Rochalimaea-like organism from a febrile patient infected with human immunodeficiency virus was confirmed. Analysis of 16S rRNA gene sequences, together with polymerase chain reaction and restriction endonuclease length polymorphism analysis of a portion of the citrate synthase gene, demonstrated that the agent is closely related to members of the genus Rochalimaea and that the isolate is genotypically identical to the presumptive etiologic agent of bacillary angiomatosis. However, the same genotypic analyses readily differentiated the new isolate from isolates of other recognized Rochalimaea species as well as other genera of bacteria previously suggested as putative etiologic agents of bacillary angiomatosis and related syndromes. We propose that the novel species be referred to as Rochalimaea henselae sp. now.

Investigations of intrinsic Pseudomonas cepacia contamination in commercially manufactured povidone-iodine.

OBJECTIVE: Laboratory investigations were initiated with a povidone-iodine antiseptic solution that was intrinsically contaminated with Pseudomonas cepacia. These investigations were helpful in understanding the microbicidal and chemical properties of iodophor solutions and the mechanism by which P cepacia can survive in iodine-containing antiseptics. DESIGN: Included in these studies were: prolonged survival of P cepacia; available and free iodine determinations; microbial challenge studies; and scanning electron microscopic examination of contaminated antiseptic. RESULTS: P cepacia survived in this iodophor antiseptic up to 68 weeks from the date of manufacture. A uniform concentration of 1% available iodine was found in all lots of povidone-iodine tested as specified on the product label, but free iodine (I2) values varied greatly. Low free iodine levels of 0.23 to 0.46 ppm were associated with the contaminated lot of povidone-iodine. Solutions of povidone-iodine with varying levels of free iodine were rapidly microbicidal when challenged with cells of P cepacia derived from culture broth and washed or adapted to growth in water. P cepacia cells taken directly from contaminated povidone-iodine survived for significantly longer periods of time. Large numbers of P cepacia were found embedded in extracellular material and among strands of glycocalyx between cells as shown by scanning electron microscopy. CONCLUSIONS: The physical thickness of cellular and extracellular material that forms on surfaces could protect embedded organisms from the microbicidal action of disinfectants and antiseptics and subsequently allow for extended microbial survival times. Manufacturers should be aware that distribution piping surfaces colonized with bacteria may be a source of product contamination and resistant organisms.

Influence of the 60-megadalton plasmid on adherence of Escherichia coli O157:H7 and genetic derivatives.

The adherence of enterohemorrhagic Escherichia coli serotype O157:H7 and various genetic derivatives to Henle 407 intestinal and HEp-2 epithelial cell lines was examined by light and electron microscopy. The parent outbreak strain, 7785, harbors a 60-megadalton serotype-specific plasmid designated pO157 and adhered to both cell lines, as determined by light microscopy. A plasmidless derivative, 2-45, showed reduced adherence to both cell lines. After being labeled with Tn801, pO157 was transformed into E. coli C600, E. coli HB101, and E. coli GH42, and back into 2-45. Both E. coli C600 and HB101 transformants adhered weakly; full adherence was restored to the 2-45(pO157::Tn801) transformant. Transmission electron microscopy (EM) demonstrated the intimate attachment of HB101(pO157::Tn801) to Henle 407 cells which formed cuplike structures and areas of possible actin polymerization adjacent to adhering bacterial cells; scanning EM further extended these observations. EM studies of E. coli O157:H7 strains were hampered by extensive intestinal cell damage, presumably due to the action of Shiga-like toxins. EM also demonstrated that 7785 and its plasmidless derivative 2-45 were piliated and that no pili were apparent on HB101(pO157::Tn801) or GH42//(pO157::Tn801). The plasmid pO157 appears to modify the eucaryotic cell adherence of E. coli O157:H7 and to confer that adherence on E. coli HB101 through surface structures other than pili. These findings, when compared with other published reports, also suggest similarities between enterohemorrhagic and enteropathogenic E. coli adherence properties.

Acanthamoeba keratitis in soft contact lens wearers. A case-control study.

Acanthamoeba keratitis is a rare, serious protozoal infection of the cornea associated with wearing contact lenses. To identify risk factors in soft contact lens wearers, we interviewed 27 patients with Acanthamoeba keratitis and 81 uninfected matched controls to compare contact lens care practices, brands of contact lenses and associated solutions, and behavioral activities. Patients were significantly more likely than controls to use homemade saline instead of commercially prepared saline (21/27 [78%] vs 14/81 [17%]; odds ratio [OR], infinity), and wear their lenses while swimming (17/27 [63%] vs 24/81 [30%]; OR, 6.2). Contact lens disinfection schedules could be determined for 25 of the patients and all of the controls. Patients were significantly more likely than controls to disinfect their lenses less frequently than recommended by lens manufacturers (18/25 [72%] vs 26/81 [32%]; OR, 5.8). Microbiologic assay of contact lens solutions from controls showed frequent contamination with high levels of bacteria. Acanthamoeba species were isolated from homemade saline solutions from two controls. These findings emphasize adherence to recommended methods of soft contact lens care, especially when using nonsterile lens care solutions.

Investigation of a new motor assessment scale for stroke patients.

The purpose of this paper is to present and describe a motor assessment scale (MAS) for stroke patients and to report on the investigation of two aspects of its reliability. The MAS is a brief and easily administered assessment of eight areas of motor function and one item related to muscle tone. Each item is scored on a scale from 0 to 6. To check interrater reliability, we videotaped five stroke patients while they were being assessed with the MAS. These scores were used as the criterion ratings. Twenty raters then assessed these patients, and their results were correlated with the criterion ratings. We determined test-retest reliability by assessing on two occasions, separated by a four-week interval, 14 stroke patients whose recovery was considered to be stable and by correlating these scores. The MAS was found to be highly reliable with an average interrater correlation of .95 and an average test-retest correlation of .98.