Safety, tolerability, and pharmacokinetics of ribavirin in hepatitis C virus-infected patients with various degrees of renal impairment.

Ribavirin (RBV) is an integral part of standard-of-care hepatitis C virus (HCV) treatments and many future regimens under investigation. The pharmacokinetics (PK), safety, and tolerability of RBV in chronically HCV-infected patients with renal impairment are not well defined and were the focus of an open-label PK study in HCV-infected patients receiving RBV plus pegylated interferon. Serial RBV plasma samples were collected over 12 h on day 1 of weeks 1 and 12 from patients with moderate renal impairment (creatinine clearance [CLCR], 30 to 50 ml/min; RBV, 600 mg daily), severe renal impairment (CLCR, <30 ml/min; RBV, 400 mg daily), end-stage renal disease (ESRD) (RBV, 200 mg daily), or normal renal function (CLCR, >80 ml/min; RBV, 800 to 1,200 mg daily). Of the 44 patients, 9 had moderately impaired renal function, 10 had severely impaired renal function, 13 had ESRD, and 12 had normal renal function. The RBV dose was reduced because of adverse events (AEs) in 71% and 53% of severe and moderate renal impairment groups, respectively. Despite this modification, patients with moderate and severe impairment had 12-hour (area under the concentration-time curve from 0 to 12 h [AUC0-12]) values 36% (38,452 ng · h/ml) and 25% (35,101 ng · h/ml) higher, respectively, than those with normal renal function (28,192 ng · h/ml). Patients with ESRD tolerated a 200-mg daily dose, and AUC0-12 was 20% lower (22,629 ng · h/ml) than in patients with normal renal function. PK modeling and simulation (M&S) indicated that doses of 200 mg or 400 mg alternating daily for patients with moderate renal impairment and 200 mg daily for patients with severe renal impairment were the most appropriate dose regimens in these patients.

Comparative performance of contact plates, electrostatic wipes, swabs and a novel sampling device for the detection of Staphylococcus aureus on environmental surfaces.

AIMS: To evaluate the performance of four sampling methods [contact plates, electrostatic wipes (wipe), swabs and a novel roller sampler] for recovery of Staphylococcus aureus from a stainless steel surface. METHODS AND RESULTS: Stainless steel test plates were inoculated with Staph. aureus, dried for 24 h and sampled using each of the four methods. Samples were either incubated directly (roller, contact plate) or processed using elution and membrane filtration (swab, wipe). Performance was assessed by calculating the apparent sampling efficiency (ASE), analytical sensitivity (Sn) and percentage of replications with positive growth. The wipe demonstrated the best performance across all inoculating concentrations (ASE(48 h) = 18%; Sn(48 h) = 7 CFU per 100 cm(2)). The swab performed well when corrected for area actually sampled (ASE(48 h) = 24%; Sn(48 h) = 76 CFU per 100 cm(2)). Of the contact-based methods, the newly developed roller sampler outperformed the contact plate (roller: ASE(48 h) = 10%; Sn(48 h) = 17 CFU per 100 cm(2); contact plate: ASE(48 h) = 0·04%; Sn(48 h) = 1412 CFU per 100 cm(2)); both contact samplers performed better at higher inoculating concentrations (6E3 CFU per 100 cm(2) for the roller and 6E6 CFU per 100 cm(2) for the contact plate). Overall, the electrostatic wipe produced the highest number of replications resulting in positive growth (74%(24 h), 91%(48 h)). CONCLUSIONS: This study demonstrates that selection of the sampling method must be carefully considered, given that different methods have varying performance. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study assessing static wipes for sampling and one that uses a more real-world-relevant 24-h drying time. The results help with infection control, and environmental health professionals choose better sampling methodologies.

Protein expression by planktonic and biofilm cells of Streptococcus mutans.

Streptococcus mutans, a major causal agent of dental caries, functions in nature as a component of a biofilm on teeth (dental plaque) and yet very little information is available on the physiology of the organism in such surface-associated communities. As a consequence, we undertook to examine the synthesis of proteins by planktonic and biofilm cells growing in a biofilm chemostat at pH 7.5 at a dilution rate of 0.1 h(-1) (mean generation time=7 h). Cells were incubated with (14)C-labelled amino acids, the proteins extracted and separated by two-dimensional electrophoresis followed by autoradiography and computer-assisted image analysis. Of 694 proteins analysed, 57 proteins were enhanced 1.3-fold or greater in biofilm cells compared to planktonic cells with 13 only expressed in sessile cells. Diminished protein expression was observed with 78 proteins, nine of which were not expressed in biofilm cells. The identification of enhanced and diminished proteins by mass spectrometry and computer-assisted protein sequence analysis revealed that, in general, glycolytic enzymes involved in acid formation were repressed in biofilm cells, while biosynthetic processes were enhanced. The results show that biofilm cells possess novel proteins, of as yet unknown function, that are not present in planktonic cells.

Effect of acid shock on protein expression by biofilm cells of Streptococcus mutans.

Streptococcus mutans is a component of the dental plaque biofilm and a major causal agent of dental caries. Log-phase cells of the organism are known to induce an acid tolerance response (ATR) at sub-lethal pH values ( approximately 5.5) that enhances survival at lower pH values such as those encountered in caries lesions. In this study, we have employed a rod biofilm chemostat system to demonstrate that, while planktonic cells induced a strong ATR at pH 5.5, biofilm cells were inherently more acid resistant than such cells in spite of a negligible induction of an ATR. Since these results suggested that surface growth itself triggered an ATR in biofilm cells, we were interested in comparing the effects of a pH change from 7.5 to 5.5 on protein synthesis by the two cell types. For this, cells were pulse labeled with [(14)C]-amino acids following the pH change to pH 5.5, the proteins extracted and separated by two-dimensional (2D) electrophoresis followed by autoradiography and computer-assisted image analysis. A comparison between the cells incubated at pH 5.5 and the control biofilm cells revealed 23 novel proteins that were absent in the control cells, and 126 proteins with an altered relative rate of synthesis. While the number of changes in protein expression in the biofilm cells was within the same range as for planktonic cells, the magnitude of their change was significantly less in biofilm cells, supporting the observation that acidification of biofilm cells induced a negligible ATR. Mass spectrometry and computer-assisted protein sequence analysis revealed that ATR induction of the planktonic cells resulted in the downregulation of glycolytic enzymes presumably to limit cellular damage by the acidification of the external environment. On the other hand, the glycolytic enzymes in control biofilm cells were significantly less downregulated and key enzymes, such as lactate dehydrogenase were upregulated during pH 5.5 incubation, suggesting that the enhanced acid resistance of biofilm cells is associated with the maintenance of pH homeostasis by H+ extrusion via membrane ATPase and increased lactate efflux.

A silicone pellet for continuous cocaine: comparison with continuous amphetamine.

An inexpensive silicone pellet is described for the continuous administration of cocaine for up to 5 days. Rats implanted with this pellet show minimal skin irritation and go through distinct behavioral stages, with an initial period of hyperactivity followed by motor stereotypies. Then, at 3-4 days after implantation, a variety of hallucinogen-like ("late-stage") behaviors appear, including limb flicks, sudden startle responses, and repetitive mid-air grasping movements. Compared to continuous d-amphetamine, continuous cocaine induces decreased motor stereotypies but heightened "late-stage" behaviors.

Peripheral teflon catheters. Potential source for bacterial contamination of orthopedic implants?

To detect low numbers of bacterial cells on Teflon catheters removed from peripheral veins, 74 catheter tips were incubated in thioglycollate media for up to ten days. Fifteen (20.3%) of the catheters were found to be culture-positive. Propionibacterium acnes was isolated from seven, Staphylococcus epidermidis from six, and Staphylococcus haemolyticus and Staphylococcus hominis from one each, all common skin organisms associated with infection of implants. An increase in documentation of bacterial contamination resulted from incubating greater than 72 hours; this allowed the slower-replicating Propionibacterium acnes to grow to detectable numbers. Because of these findings and those of others, attention is focused on the peripheral vein conduit as a potential source for hematogenous seeding of implants with bacterial cells. Changing peripheral catheters within 24 hours is recommended to reduce the constant risk of occult bacteremia.

Altered protein expression of Streptococcus oralis cultured at low pH revealed by two-dimensional gel electrophoresis.

Streptococcus oralis is the predominant aciduric nonmutans streptococcus isolated from the human dentition, but the role of this organism in the initiation and progression of dental caries has yet to be established. To identify proteins that are differentially expressed by S. oralis growing under conditions of low pH, soluble cellular proteins extracted from bacteria grown in batch culture at pH 5.2 or 7.0 were analyzed by two-dimensional (2-D) gel electrophoresis. Thirty-nine proteins had altered expression at low pH; these were excised, digested with trypsin using an in-gel protocol, and further analyzed by peptide mass fingerprinting using matrix-assisted laser desorption ionization mass spectrometry. The resulting fingerprints were compared with the genomic database for Streptococcus pneumoniae, an organism that is phylogenetically closely related to S. oralis, and putative functions for the majority of these proteins were determined on the basis of functional homology. Twenty-eight proteins were up-regulated following growth at pH 5.2; these included enzymes of the glycolytic pathway (glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase), the polypeptide chains comprising ATP synthase, and proteins that are considered to play a role in the general stress response of bacteria, including the 60-kDa chaperone, Hsp33, and superoxide dismutase, and three distinct ABC transporters. These data identify, for the first time, gene products that may be important in the survival and proliferation of nonmutans aciduric S. oralis under conditions of low pH that are likely to be encountered by this organism in vivo.

Testing of pit and fissure sealants in the monkey.

A pilot study was conducted employing the Macaca speciosa monkey to determine the retention and sealing ability of pit and fissure sealants in vivo. Several problems were encountered in the use of this animal model for this type of evaluation. Without doubt, the conditions to which the sealants were subjected in the monkey were more rigorous than those found in man. This is attested to by the lower rate of retention of sealants as compared to that found in studies on human beings. To increase the usefulness of animal studies of this type, additional research should be done to better establish the correlation between the behavior of sealants in the animal and in man. Nevertheless, certain pertinent observations were made, one of which is that in some instances where the sealant was retained on the teeth, the sealant-tooth interface was readily penetrated by an isotope solution.

Septopal beads and autogenous bone grafting for bone defects in patients with chronic osteomyelitis.

Thirty-five patients with chronic osteomyelitis were treated with autogenous bone grafts for bone defects. Of 35 patients, two were lost to follow-up evaluation. There were 27 men and six women. The age range was from 18 to 62 years (median age, 29 years). The bones included 22 tibias, nine femurs, and two ulnas. The size of the bone defects ranged from 2.5 x 15 cm (median defect, 2.5 x 6 cm). The length of infection ranged from two to 540 months (median, 31 months). Twenty patients had nonunions and 19 patients required soft-tissue muscle transfers. Patients were treated with systemic antibiotics and/or gentamicin (Septopal) antibiotic beads. Twelve patients were treated with Septopal beads. The range of follow-up evaluation was 24 to 68 months (median, 47 months). Thirty-one of 33 patients had one bone-graft procedure and two patients required two. The time from initial debridement and infection control to bone graft for patients not requiring soft-tissue muscle flaps was one to six weeks (median time, four weeks). For patients requiring soft-tissue muscle transfer, the range was six to nine weeks (median, six weeks). The median time to bone-graft incorporation was six months. All fractures united. Complications included two refractures from auto accidents in the immediate postoperative period, one partial muscle loss, one skin-graft loss, four pin tract draining sites, and two antibiotic-related skin rashes. There was one recurrent infection, and the infection arrest rate was 97%.(ABSTRACT TRUNCATED AT 250 WORDS)

LeFort I orbitotomy: a new approach to the inferonasal orbital apex.

Numerous approaches to the orbit have been elegantly described in the literature. One area of the orbit that remains difficult to approach with standard techniques is the inferonasal apex. We describe a new surgical procedure we have termed the LeFort I orbitotomy. The technique involves creation of a LeFort I osteotomy to separate the maxilla from the zygoma and nose bilaterally. The posterior inferomedial orbital bone is then removed and the periorbita opened. This approach allows a more direct, less tangential view to this area of the orbit than does a Caldwell-Luc approach. Wider access for tumor manipulation is gained than would be possible with a transnasal endoscopic approach. An illustrative case report is presented.

Saw-toothed grain beetleOryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) : Collection, identification, and bioassay of attractive volatiles from beetles and oats.

Over 200 beetle- and food-produced volatiles were collected from cultures of the saw-toothed grain beetleOryzaephilus surinamensis (L.) on oats. It proved possible to develop the electroantennogram recording technique for these beetles, despite their small size, allowing volatiles causing antennal responses to be identified by coupled GC-EAG and subsequent GCMS techniques. Three beetle-produced macrolide lactones were identified as (Z,Z)-3,6-dodecadien-11-olide, (Z,Z)-3,6-dodecadienolide, and (Z,Z)-5,8-tetradecadien-13-olide in an average ratio of 4.4∶1∶2. These have been reported as components of the aggregation pheromone from a different population of this species, although the ratio of the components produced was different. Three food volatiles with EAG activity were also identified: 1-octen-3-ol, 3-octanone, and nonanal. A mixture of the six identified volatiles produced similar levels of attraction, in a behavioral assay, to the entire mixture of collected volatiles.

Intra-oral acid production associated with eating whole or pulped raw fruits.

The hypotheses that raw fruits, whether whole or pulped, were cleared rapidly from the mouth and that the sugars in the whole and pulped fruits are fermented with equal efficiency to acids by the oral microflora were tested in this study. Groups of 7-9 adult subjects chewed 10 g of raw, whole or pulped fruit (apple, banana, orange, pear and pineapple) for 1 min and whole, unstimulated saliva samples were collected during the following 60-min interval. Each saliva sample was assayed for the concentrations of fruit-derived sugars (glucose, fructose and sucrose), fruit-derived acids (malic and citric) and acids which may be produced as a result of bacterial fermentation (acetic, lactic, formic and succinic). We found the fruit-derived sugars were rapidly cleared from the mouth (within 5 min). The major bacterially produced acids were lactic and succinic, which reached maximum concentrations in the 5-min sample. There was no significant difference, within a fruit, in the salivary levels of any of the sugars or acids between the raw whole or raw pulped forms. In light of these findings it seems unwise to assume that fruits may be consumed without consideration of their acidogenic potential.

Comparison of the clinical efficacy and tolerance of gentamicin PMMA beads on surgical wire versus combined and systemic therapy for osteomyelitis.

These data do not prove a statistical superiority of conventional antibiotics or Septopal in the treatment of chronic osteomyelitis. This result, however, is complicated by the biased data set represented by the combined treatment. The data do suggest that cost of treatment is considerably less in patients who are treated with local antibiotics (i.e., Septopal) alone. The rate of adverse experiences was directly related to the use of parenteral antibiotics, with higher rates of adverse experiences in the conventional and combined treatment groups. Furthermore, the Cierny-Mader Physiologic Class had the best correlation with outcome, suggesting that host factors are probably of critical importance in inducing remission of chronic osteomyelitis. This protocol was not designed to test the role of debridement in the treatment of osteomyelitis: it was assumed that debridement would be the same in both groups. It is the investigators' strong opinion, however, that adequacy of debridement was an important determinant in quiescence or recurrence in the study patients. Similarly, there was no strict control for adequacy of soft-tissue coverage provided by local or distant tissue transfer. Again, the investigators believe that adequacy, including viability and durability, of soft-tissue covering was an important determinant for the end result in these patients. Other covariants such as smoking, history, nutritional status, and other measures of general health will be added to this model when data are available. This analysis will allow definition of the appropriate clinical situations in which use of Septopal alone or combined with parenteral antibiotic is indicated.