Influence of food on the absorption of albuterol Repetabs

A study was conducted in 12 healthy, nonsmoking male volunteers to examine the effect of food intake on the absorption profile of albuterol repeat-action tablets. This randomized crossover study consisted of two phases separated by a 1-week washout period. All subjects fasted 10 hours preceding drug administration. Each subject received two 4 mg albuterol repeat-action tablets with and without a high fat content breakfast. Plasma albuterol concentrations were determined by a gas chromatographic/mass spectrophotometric assay. Relative bioavailability was assessed by comparing areas under the plasma-albuterol concentration time curves as well as peak concentrations and time to peak concentration. No significant differences were noted between the two treatment phases in the area under the curve or peak plasma concentrations. The areas under the curve were 100 and 105 hr.ng/ml when the drug was administered with and without food, respectively. The corresponding peak plasma concentration values were 9.4 and 10.4 ng/ml, respectively. The only significant difference observed was in the maximum time to reach peak plasma concentrations, which was delayed by about 1 hour when the drug was administered with food. Therefore, food has minimal effect on the absorption of albuterol from repeat-action tablets.     

Microstructural disassembly of calcium phosphates

Microstructural factors may play a role in the osseointegration of calcium phosphates. In this paper, direct microstructural interactions between crystalline calcium phosphates and the biological milieu are reported. Degradation via exposure to osteoblast culture closely resembles in vivo interactions with subcutaneous tissues in a bovine model at early time periods. That these interactions were common to both experiments constitutes one of the few known examples of in vitro-in vivo correspondence. Interestingly, the degradation of phase pure hydroxyapatite (HA) in vitro was more rapid than that of biphasic HA in vivo. In both cases, grain extraction/pullout was frequently observed. This suggests a connection to smaller-scale observations of epitaxial CHA nucleation and growth on pre-existing HA grains. A microstructure in which the grain boundary is dissolving/corroding can apparently be disassembled by forces transmitted through biological structures. These observations are distinct from those of simple non-biological solutions and prove that biological environments can interact with the material beneath the ceramic-cell/ceramic-tissue interface. Many often ignored microstructural factors-grain size, shape, grain boundary strength and the presence of impurity phases-may in fact control degradation. We also suggest that even relatively modest initial grain sizes will, in combination with the mild/absent foreign body response to calcium phosphates, result in lengthy in vivo particle resistence.     

The effect of experimental iron-overload on splenic T cell function: analysis using cloning techniques.

The effect of iron-overload on cell-mediated immunity was examined in C57 mice. Two methods of iron-loading were used: (i) dietary carbonyl iron which produced iron-loading primarily of parenchymal cells or (ii) intraperitoneal administration of iron-dextran which produced iron-loading predominantly of Kupffer cells. Both methods of iron-loading resulted in a diminished capacity of spleen cells to generate an allo-specific cytotoxic response in the absence of exogenous interleukin 2 (IL-2). Exogenous IL-2, however, restored the ability of spleen cells from iron-loaded mice to generate allo-specific cytotoxicity in bulk culture. Clonal assays for the precursor cells of cytotoxic T lymphocytes (CTL-P), performed in the presence of added IL-2, demonstrated that iron-loaded mice contained normal numbers of CTL-P. However, cultures of spleen cells from carbonyl iron-loaded mice generated less IL-2 following Concanavalin A stimulation, apparently as a result of a reduction in the number of IL-2-secreting cells amongst the spleen cell population. This work presents further evidence that iron-overload is associated with defective immunoregulatory control.     

Li+ inhibition of membrane current responses to epinephrine in guinea-pig ventricular cells

Membrane currents of guinea-pig ventricular myocytes were recorded using the whole-cell voltage clamp method. The epinephrine-induced increase in Ca²⁺ current (2.9±0.5 times control) was reduced (1.8 ±0.3 times) by replacing Na⁺ with Li⁺ in the bathing solution. In addition, 0.5 M epinephrine increased a time-independent membrane conductance in the Na⁺ external solution, having a reversal potential of –19 ±3 mV (epinephrine-induced current). In the Li⁺ external solution, however, 0.5 M epinephrine failed to induce the epinephrine-induced current. The findings are consistent with the reported Li⁺ inhibition of GTP-binding protein and/or adenylate cyclase.     

C3 degradation products (C3d) in normal pregnancy.

Plasma C3 degradation products (C3d) were measured in 65 normal pregnancies and compared with those of non-pregnant women. No significant difference was detected between the two groups, although a difference had been previously reported. Plasma C3d estimations give an indication of complement activation and may be used as an indicator of disease activity in patients with systemic lupus erythematosus (SLE), irrespective of pregnancy.     

Modulation of Whole-Cell Currents in Plasmodium Falciparum-Infected Human Red Blood Cells by Holding Potential and Serum

Recent electrophysiological studies have identified novel ion channel activity in the host plasma membrane of Plasmodium falciparum -infected human red blood cells (RBCs). However, conflicting data have been published with regard to the characteristics of induced channel activity measured in the whole-cell configuration of the patch-clamp technique. In an effort to establish the reasons for these discrepancies, we demonstrate here two factors that have been found to modulate whole-cell recordings in malaria-infected RBCs. Firstly, negative holding potentials reduced inward currents (i.e. at negative potentials), although this result was highly complex. Secondly, the addition of human serum increased outward currents (i.e. at positive potentials) by approximately 4-fold and inward currents by approximately 2-fold. These two effects may help to resolve the conflicting data in the literature, although further investigation is required to understand the underlying mechanisms and their physiological relevance in detail.     

Inflammatory cytokine response to Vibrio vulnificus elicited by peripheral blood mononuclear cells from chronic alcohol users is associated with biomarkers of cellular oxidative stress

Vibrio vulnificus is the leading cause of death in the United States associated with the consumption of raw seafood, particularly oysters. In epidemiological studies, primary septicemia and inflammation-mediated septic shock caused by V. vulnificus is strongly associated with liver disease, often in the context of chronic alcohol abuse. The present study was undertaken to determine whether clinical biomarkers of liver function or cellular oxidative stress are associated with peripheral blood mononuclear cell inflammatory cytokine responses to V. vulnificus. Levels of interleukin-1 beta (IL-1 beta), IL-6, IL-8, and tumor necrosis factor alpha elicited in response to V. vulnificus and measured in cell supernatants were not associated with the liver biomarkers aspartate aminotransferase (AST) or alanine aminotransferase (ALT) or the AST/ALT ratio. In contrast, reduced glutathione (GSH) levels were associated with the release of all four cytokines (IL-1 beta [R(2) = 0.382; P = 0.006], IL-6 [R(2) = 0.393; P = 0.005], IL-8 [R(2) = 0.487; P = 0.001], and TNF-alpha [R(2) = 0.292; P = 0.021]). Those individuals with below-normal GSH levels produced significantly less proinflammatory cytokines in response to V. vulnificus. We hypothesize that persons with markers for cellular oxidative stress have increased susceptibility to V. vulnificus septicemia.     

Methods for optimal recovery of Malassezia furfur from blood culture.

Malassezia furfur, a recently described agent of catheter-associated sepsis, requires long-chained fatty acids for in vitro growth. To determine optimum conditions for recovery of the organism from blood culture, we compared a radiometric (BACTEC) with a lysis centrifugation-direct agar plating (Isolator) blood culture method. When blood culture isolates of M. furfur were suspended in phosphate-buffered saline and used as inocula, the BACTEC system detected the organisms radiometrically only when bottles were supplemented with lipid compounds; detection was often delayed (greater than or equal to 72 h) when small inoculum sizes were tested. The Isolator pediatric tube system detected growth of M. furfur within 48 h of plating onto a lipid-supplemented agar medium. Simulated blood culture experiments showed that the addition of whole human blood and Intralipid to the BACTEC 6B bottle was associated with rapid lysis of erythrocytes, accumulation of a chocolate brown sediment in the bottles, and fungicidal activity to the M. furfur isolates. In contrast, suspensions of M. furfur in whole human blood were stable for at least 8 h in Isolator tubes and quantitatively recoverable after plating onto agar. Of the two systems studied, the Isolator tube system provided a more suitable procedure for isolation of M. furfur from blood culture.     

In situ localization of pea enation mosaic virus double-stranded ribonucleic acid

Precursor ([³H]uridine) incorporation studies in the presence or absence of actinomycin D (AMD) showed that AMD-insensitive nucleic acid synthesis occurred only in the nuclei in pea enation mosaic virus (PEMV)-infected pea plant tissues. Ferritin-labeled antibody studies showed that ds-RNA was present only in nuclei. In vitro hybridization of the nucleic acid from various infected or healthy cell fractions with [¹²⁵I]PEMV-ss-RNA indicated that PEMV-ds-RNA was primarily associated with nuclei-enriched fractions from infected cells.An in situ hybridization technique, which utilized autoradiography to detect the subcellular location of material which hybridized with [¹²⁵I]PEMV-ss-RNA, was developed. This method confirmed that PEMV-ds-RNA was localized in the nuclei of PEMV-infected tissues.