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PubMed1990

Electron microscopic study of coexpression of adhesive protein capsules and polysaccharide capsules in Escherichia coli.

Escherichia coli 21535 (O21:K4:H4 with nonfimbrial adhesin NFA-6) and 21511 (O7:K98:H6 with nonfimbrial adhesin NFA-4) were analyzed by immunoelectron microscopy with a K98-specific antiserum and K4- and NFA-4-specific and NFA-6-reactive monoclonal antibodies. The bacteria were analyzed in ultrathin sections after stabilization of the capsules with specific antibodies by embedding in Epon 812 as well as in Lowicryl K4M. With the Lowicryl-embedded samples, the polysaccharide K antigens were labeled by the immunogold technique. It was found that with both strains all bacteria expressed the polysaccharide capsule, while in each case about 20% expressed the protein capsule in addition. Thus, in both invasive E. coli strains, bacteria are present which express composite capsules with the adhesin (recognition protein) at the cell-distal outer region and the K antigen (acidic polysaccharide) at the cell-proximal inner region. These findings are discussed with respect to the participation of the capsular compartments in unspecific host defense.

Adhesins, Escherichia coli↗

PubMed1975

Soft gelatin capsules II: Oxygen permeability study of capsule shells.

A method is reported for studying the effects of several factors at room temperature on the oxygen permeability of soft gelatin capsule shell films. The method involves the use of a permeability cell assembly and the spectrophotometric determïnation of oxygen with an alkaline pyrogallic acid solution. Factors investigated were relative humidity, plasticizers, equilibrium water, an insoluble additive, and film thickness. Results from the effects of film thickness and oxygen partial pressure correlated well with the permeability equation. For greatest stability of encapsulated oxygen-labile materials, it is recommended that the soft gelatin capsule shells be prepared with a low plasticizer concentration and that the finished capsules be stored at low relative humidity.

Capsules↗

PubMed1987

Multiple tamping effects on drug dissolution from capsules filled on a dosing-disk type automatic capsule filling machine.

The effects of number of tamps and tamping force on drug dissolution from capsules filled on an instrumented dosing-disk automatic capsule filling machine (Hofliger-Karg) were studied using hydrochlorothiazide as a model, low dose, poorly soluble drug. Generally, there was a trend toward slower dissolution rate with increasing numbers of tamps, the effect being most marked when insoluble dicalcium phosphate dihydrate was the filler. Higher compression forces improved drug release when anhydrous lactose was the filler, but adversely affected the dicalcium phosphate-based capsules. Inclusion of 4% croscarmellose sodium disintegrant tended to nullify the effects of number of tamps or tamping force with both fillers; however, the disintegrant also markedly enhanced drug dissolution from the dicalcium phosphate-based formulation. Hydrochlorothiazide dissolution from the latter formulation without disintegrant appeared to follow a "diffusion from insoluble matrix" model regardless of number of tamps or their intensity. Mercury intrusion pore size distribution data for some plugs suggested that for tamps of equal force (100 or 200 N), further powder consolidation after two tamps does not occur.

Capsules↗

PubMed1987

Analysis of the K1 capsule biosynthesis genes of Escherichia coli: definition of three functional regions for capsule production.

Transposon and deletion analysis of the cloned K1 capsule biosynthesis genes of Escherichia coli revealed that approximately 17 kb of DNA, split into three functional regions, is required for capsule production. One block (region 1) is required for translocation of polysaccharide to the cell surface and mutations in this region result in the intracellular appearance of polymer indistinguishable on immunoelectrophoresis to that found on the surface of K1 encapsulated bacteria. This material was released from the cell by osmotic shock indicating that the polysaccharide was probably present in the periplasmic space. Insertions in a second block (region 2) completely abolished polymer production and this second region is believed to encode the enzymes for the biosynthesis and polymerisation of the K1 antigen. Addition of exogenous N-acetylneuraminic acid to one insertion mutant in this region restored its ability to express surface polymer as judged by K1 phage sensitivity. This insertion probably defines genes involved in biosynthesis of N-acetylneuraminic acid. Insertions in a third block (region 3) result in the intracellular appearance of polysaccharide with a very low electrophoretic mobility. The presence of the cloned K1 capsule biosynthesis genes on a multicopy plasmid in an E. coli K-12 strain did not increase the yields of capsular polysaccharide produced compared to the K1+ isolate from which the genes were cloned.

Antigens, Bacterial↗

PubMed1999

Preventing posterior capsule opacification by creating a discontinuous sharp bend in the capsule.

PURPOSE: To clarify which factor--intraocular lens (IOL) design or material--contributes most to the inhibition of migrating lens epithelial cells (LECs). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: After phacoemulsification, an acrylic IOL with sharp optic edges was implanted in 1 eye and a poly(methyl methacrylate) (PMMA) IOL with an optic design similar to that of the acrylic IOL in the contralateral eye of 4 rabbits. RESULTS: The Miyake view and histopathological findings 3 weeks after surgery revealed that the lens capsule wrapped tightly around the optic edges, conforming to a distinctly sharp rectangular bend there with both IOL types in all rabbits. The migrating-LECs were inhibited at the site, and a massive Soemmering's ring cataract was formed. CONCLUSIONS: The discontinuous sharp capsule bend created by the sharp optic edges in both IOL types appeared to induce contact inhibition of the migrating LECs. The preventive effect of an acrylic IOL on posterior capsule opacification may be design dependent.

Acrylic Resins↗

PubMed2001

Posterior capsule opacification and anterior capsule opacification.

Posterior capsule opacification (PCO) is still the most frequent complication of cataract surgery. A variety of studies has led to a better understanding of the pathogenesis of PCO, and strategies of molecular biology have produced new therapeutic options, such as immunological techniques or gene therapeutic approaches. Surgical strategies and intra-ocular lens-dependent factors also are capable to reduce the rate of PCO. In-the-bag implantation of intra-ocular lenses with a sharp optic edge seems to be effective in inhibiting equatorial lens epithelial cell migration to the center of the posterior capsule. Several PCO documentation systems have been developed that will lead to more exact and better comparable recording of PCO rates. In the year 2000, PCO or secondary cataract is still the most frequent complication after extracapsular cataract surgery. In a 1998 meta-analysis, PCO rates of 11.8% 1 year after extracapsular cataract surgery with intraocular lens implantation, 20.7% after 3 years, and 28.4 % after 5 years have been reported. For the United States, it has been estimated that the overall expenses for treatment of PCO are only exceeded by the costs for cataract treatment itself. In the past decade, a lot of experimental and clinical studies have been performed on this topic. They have led to 1) to a better understanding of the pathogenesis of the development of anterior and posterior capsule opacification; 2) more objective and better comparable systems of documentation and analysis of PCO; and a number of 3) surgical and 4) pharmaceutical strategies to prevent PCO.

Cataract↗

PubMed2003

Pharmacokinetics of once-daily saquinavir hard-gelatin capsules and saquinavir soft-gelatin capsules boosted with ritonavir in HIV-1-infected subjects.

OBJECTIVE: To investigate the pharmacokinetics of once-daily saquinavir (SQV) hard-gelatin capsule (HGC)/ritonavir (RTV), 1600/100 mg, compared with once-daily SQV soft-gelatin capsule (SGC)/RTV, 1600/100 mg. METHODS: We evaluated 13 randomly selected HIV-1-infected subjects taking once-daily SQV SGC/RTV, 1600/100 mg, plus dual nucleoside reverse transcriptase inhibitors (NRTIs) in this pharmacokinetic (PK) substudy. Subjects took 1 week of SQV HGC/RTV and NRTIs, followed by steady-state SQV PK determinations. Subjects then changed to SQV SGC/RTV and NRTIs for 1 week, followed again by steady-state SQV PK determinations. Area under the plasma concentration versus time curve (AUC), maximum concentration (C(max)), minimum concentration (C(min)), time to C(max), and elimination half-life were calculated. RESULTS: There was no significant difference in AUC values between HGCs and SGCs, with a median (plus interquartile range [IQR]) of 50.0 (42.6-71.5) versus 35.5 (28.0-50.2) mg/L/h, respectively ( =.056). Intersubject variability resulted in 4 of 13 subjects on the SQV SGCs and 2 of 13 subjects on the SQV HGCs having a C(min) below the minimum effective concentration of 0.05 mg/L. CONCLUSION: Once-daily SQV HGCs, 1600 mg, boosted with once-daily RTV, 100 mg, resulted in PK parameters that were similar to those observed with 1600 mg of SQV SGC/100 mg RTV once daily. Once-daily SQV HGC/RTV, 1600/100 mg, may be easier to use in developing countries and may increase access where drug costs can be less, the capsule size is smaller, and the need for refrigeration is lessened.

Administration, Oral↗

PubMed2007

Long-term results of sealed capsule irrigation using distilled water to prevent posterior capsule opacification: a prospective clinical randomised trial.

BACKGROUND: We investigated long-term safety and efficacy of sealed capsule irrigation (SCI) during cataract surgery to prevent posterior capsule opacification (PCO). METHODS: One eye of each of 17 patients (mean age: 70.1+/-9.7 years) who presented with bilateral cataracts was randomly chosen for SCI treatment. After phacoemulsification, the capsular bag was vacuum sealed with the PerfectCapsule device (Milvella) followed by SCI using distilled water for two minutes. No vacuum loss occurred during irrigation. Each patient's fellow eye served as a control. One hydrophilic acrylic intraocular lens model was implanted in all eyes. Five patients had to be excluded due to deep anterior chamber, small pupil or unilateral surgery. Follow-up examinations took place one day and one, three, six, 12 and 24 months after surgery. We evaluated safety parameters, anterior capsule (AC) overlapping and PCO. RESULTS: Postoperatively, mean best corrected visual acuity, pachymetry, endothelial cell count, intraocular pressure, AC overlapping and PCO showed no statistically significant difference between SCI and the control group (p>0.05, Wilcoxon test). CONCLUSION: SCI is a safe procedure and enables the specific pharmacological targeting of lens epithelial cells inside the capsular bag. Using distilled water, however, it is not possible to reduce PCO development significantly. Thus, alternative substances should be evaluated.

Adult↗

PubMed1959

Determination of type in capsulated transformants on pneumococcus by the genome of non-capsulated donor and recipient strains.

Capsulated transformants producing type II polysaccharide have been obtained by reactions between a number of R mutants of type II pneumococcus. All the IIR strains except II-R36 yielded extracts which transformed 2 VIIIR strains to VIIIS. Two of the IIR strains were transformed to VIIIS by an extract of 1 VIIIR strain. The most striking result was the production of both IIS and VIIIS transformants by the action of extracts of both VIIIR strains applied to cells of II-RB. This suggests that the determination of capsular type in pneumococcus does not depend on single allelomorphic genes; it seems more likely that a number of genes may be required to determine type specificity, and that some genes may be common to different types, possibly in connection with common biochemical pathways for some stages of polysaccharide synthesis. This is further indicated by the finding that extracts of capsulated strains of each of the types I, II, III, VII, VIII, XIV, and XVIII are capable of giving IIS transformants with 1 or more of the IIR strains in addition to the expected donor-type transformants. Strain II-R36 was transformed by extracts of all S types except type VII, but the only transformants found were of the donor type. It appears that II-R36 may have multiple genetic deficiencies for type II capsulation, possibly in the form of a deletion. This may be the case also with IIIS strains since only IIIS transformants were found when IIIS extract was applied to any of the IIR strains.

Polysaccharides↗

PubMed1990

Biosynthesis of the polysialic acid capsule in Escherichia coli K1. Cold inactivation of sialic acid synthase regulates capsule expression below 20 degrees C.

When neuroinvasive Escherichia coli K1 cells are grown at temperatures below 20 degrees C, they fail to synthesize the alpha-2,8-linked polysialic acid (polySia) capsule. The objective of this study was to use a genetic and biochemical approach to analyse why capsule expression was defective at cold temperatures. The strategy was to construct E.coli K1-derived mutants with defects in activation and degradation of Sia. The inability to degrade Sia because of a defect in the Sia-specific aldolase permitted accurate quantitation of Sia and CMP-Sia. Strains EV5 and EV90 possessed a defective CMP-Sia synthetase and were unable to activate Sia. These mutants were then used to study how synthesis of Sia, CMP-Sia, and the polySia capsule was affected by growth at 15 degrees C. In contrast to wild type strains, the mutants accumulated Sia in considerable quantities (up to 100 nmol mg protein-1) at 37 degrees C. However, no Sia was detected after growth at 15 degrees C. A temperature upshift experiment showed that the intracellular concentration of Sia increased ca. 3-fold within 5-10 min after shift from 15 to 37 degrees C, even in the presence of inhibitors of protein synthesis or transcription initiation. An in vitro assay for Sia synthase showed that Sia was synthesized at 37 degrees C in cell-free extracts from both 37 and 15 degrees C grown cells, but that no synthesis occurred when the same extracts were assayed at 15 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Radioisotopes↗

PubMed1975

Escherichia coli capsule bacteriophages. IV. Free capsule depolymerase 29.

The free host capsule depolymerase, induced by Escherichia coli capsule bacteriophage no. 29, and causing the formation of haloes around its plaques, has been purified to homogeneity. As judged from the following facts, this "enzyme" consists of free phage 29 spikes. (i) Detached phage organelles and depolymerase 29 particles exhibit the same molecular weight (about 245,000, as determined from the sedimentation equilibrium), contain polypeptide chains of the same two sizes (57,000 plus or minus 3,000 and 29,500 plus or minus 2,000, as determined by SDS-PAA gel electrophoresis), and have (within experimental error) the same sedimentation coefficient, isoelectric point, and amino acid composition. (ii) Isolated depolymerase and phage spikes in situ both catalyze the hydrolysis of glucosidic bonds in host capsular polysaccharide, leading ultimately to the formation of oligosaccharide fragments of one, two, and three hexasaccharide repeating units. (iii) Depolymerase 29 and phage 29 spikes have roughly the same electron optical dimensions. As tentatively estimated from the total and the virus-associated capsule depolymerase activity in the lysates, phage 29 infection seems to produce eight to seventeen times more free than incorporated spikes.

Amino Acids↗

PubMedDate not supplied

Sustained release properties of the once daily theophylline capsule BY912 as compared with Theo-24 capsules.

In a multiple dose cross-over experiment in 12 healthy male adults the bioavailability and sustained release characteristics of new once daily BY912 400 mg theophylline capsules (= B, Byk Gulden Research Laboratories, FRG) were studied using Theo-24 capsules (= T, Searle & Co., USA) as reference. Both products were given once daily for a period of 7 days as an 800 mg theophylline dose at 8 am, half an hour after a standardized breakfast. Theophylline concentrations in plasma were measured on days 1, 6, and 7 using high-performance liquid chromatography. Significantly better sustained release characteristics, resulting in longer plateau time (t75%, 11.6 vs 9.2 h on day 6 and 13.1 vs 8.8 h on day 7) and smaller per cent peak-trough fluctuation in the steady state (per cent PTF, 80 vs 103 per cent on day 6 and 66 vs 100 per cent on day 7), were found for B in comparison with T. The extent of absorption on both days, however, was smaller for B compared with T (relative bioavailability 84 per cent and 81 per cent, respectively). In conclusion, the absorption of theophylline from B resulted in a more extended shape of the plateau phase, indicating better sustained release characteristics. The extent of absorption, however, over the dosing intervals was more complete with T.

Adult↗

PubMed1982

Comparison of the effectiveness of several formulations of sodium valproate: tablets, enteric-coated capsules, solutions and rectal capsules.

The effects of an oral enteric-coated preparation (VAL 579 capsules) of sodium valproate (VPA) were compared with those of conventional oral and rectal preparations in 24 epileptic patients. Enteric-coated capsules are useful for avoiding gastric intolerance to VPA. Plasma VPA level peaks after the enteric- coated form were later than after other forms. The bioavailability appeared to be the same for all the forms.

Adolescent↗

PubMed1998

Comparative pharmacokinetic study of a floating multiple-unit capsule, a high-density multiple-unit capsule and an immediate-release tablet containing 25 mg atenolol.

The purpose of this study was to evaluate the possible advantages of floating and high-density dosage forms and their influence on pharmacokinetic parameters. Atenolol was chosen as a model drug because of its poor absorption in the lower gastrointestinal tract. Three formulations containing 25 mg atenolol, a floating multiple-unit capsule, a high-density multiple-unit capsule, and an immediate-release tablet were compared with respect to estimated pharmacokinetic parameters. The two multiple-unit dosage forms were composed of compressed minitablets and had sustained release properties. The bioavailability of the two gastroretentive preparations with sustained release characteristics was significantly decreased when compared to the immediate-release tablet. The floating minitablets seemed to be retained longer in the stomach than the high-density dosage form. The first atenolol concentration detectable in the plasma and the time to peak Tmax were delayed for the floating dosage form. For the parameters Cmax and AUC 0-infinity, the lower limit of the 90% confidence interval was outside the bioequivalence range (0.80-1.25). This study showed that it was not possible to increase the bioavailability of a poorly absorbed drug such as atenolol using gastroretentive formulations. Atenolol absorption was delayed and the maximum plasma concentration was diminished.

Adrenergic beta-Antagonists↗

PubMed1998

Measuring the anterior capsule opening after cataract surgery to assess capsule shrinkage.

PURPOSE: To measure anterior capsule opening (ACO) size after acrylic intraocular lens (IOL) implantation and study the natural course of ACO reduction. SETTING: Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan. METHODS: This study comprised 32 patients (38 eyes) having continuous curvilinear capsulorhexis, phacoemulsification, acrylic IOL implantation, and a self-sealing incision performed by 1 surgeon. A retroillumination photograph of the ACO was obtained with the Anterior Eye Segment Analysis System and converted to a computer image. The images were used to measure ACO size postoperatively and calculate the reduction ratio. Follow-up was 6 months. RESULTS: The postoperative reduction ratio in ACO size was 2.14% at 1 week, 3.83% at 1 month, 4.29% at 3 months, and 5.03% at 6 months. In a few cases, the reduction was progressively severe throughout the follow-up. CONCLUSIONS: The anterior capsule opening shrank rapidly during the first month after acrylic IOL implantation, followed by a slower progressive reduction in the subsequent 6 months. When severe, progressive shrinkage occurs, an anterior neodymium:YAG laser capsulotomy should be performed within 2 months postoperatively.

Acrylic Resins↗

PubMed2003

Pharmacokinetic and tolerability profile of twice-daily saquinavir hard gelatin capsules and saquinavir soft gelatin capsules boosted with ritonavir in healthy volunteers.

OBJECTIVE: To evaluate the pharmacokinetics and safety of a boosted saquinavir (SQV)/ritonavir (RTV) combination, administered as either the hard gelatin capsule (HGC) or soft gelatin capsule (SGC) formulation of SQV, in 24 healthy volunteers. METHODS: This was a single-centre, open-label, randomized, 2 x 2 crossover study. Twelve subjects were randomized to receive SQV/RTV 1000 mg/100 mg twice daily (BID) orally for 10 days, as either the HGC or SGC formulation. The pharmacokinetic profile of SQV was determined on day 10. Subjects then crossed over to the opposite SQV formulation, and the pharmacokinetic profile was determined again on day 20. The primary analysis was the assessment of bioequivalence based on logarithmically transformed values for AUC(0-24 h) and Cmax for the two formulations. RESULTS: There was a statistically significant increase in the geometric means of all the pharmacokinetic variables evaluated for SQV-HGC/RTV compared with SQV-SGC/RTV. A mean AUC0-24 h-value of 15.798 micro g/mL/h was reported for the HGC formulation compared with 11.655 micro g/mL/h for the SGC formulation (P = 0.0043). The SQV-HGC/RTV combination was better tolerated in terms of gastrointestinal system disorders. Furthermore, no elevations in triglycerides or total cholesterol were reported with SQV/RTV during the entire study period. CONCLUSION: In healthy volunteers, RTV boosting of SQV-HGC produces plasma exposures at least comparable to SQV-SGC, which is accompanied by an improvement in gastrointestinal system disorders.

Adult↗

PubMed2000

Stability of the powdered dosage form prepared by unsealing the capsules: water vapor sorption and discoloration of the powdery contents of clorazepate dipotassium capsules.

The hygroscopicity of the contents of clorazepate dipotassium (Mendon) capsules (CM) was investigated by storage at various relative humidities (RHs). The CM adsorbed water vapor significantly at more than 75% RH. At the same time, a marked discoloration of CM from white to yellow was also observed during storage. On the basis of differential scanning calorimetry (DSC) and Fourier transform (FT) Raman spectroscopy, the discoloration seemed to be due to the change in clorazepate dipotassium to nordiazepam and other substances. It was found that, when opening of the Mendon capsule is necessary to prepare the powdered dosage form, the CM should be stored below 60% RH to avoid the adsorption of water vapor and discoloration.

Anti-Anxiety Agents↗

PubMed2000

Baseline human immunodeficiency virus type 1 phenotype, genotype, and RNA response after switching from long-term hard-capsule saquinavir to indinavir or soft-gel-capsule saquinavir in AIDS clinical trials group protocol 333.

AIDS Clinical Trials Group protocol 333 was an open-label trial of a switch from saquinavir (SQV) hard capsules (SQVhc) to indinavir (IDV) or saquinavir soft-gel capsules (SQVsgc) after >48 weeks of prior treatment with SQVhc. Eighty-nine subjects received IDV or SQVsgc or continued to receive SQVhc and continued unchanged treatment with non-protease-inhibitor antivirals for 8 weeks. Subjects receiving SQVhc then switched treatment to IDV. Baseline drug susceptibility and protease gene sequencing were done; 12 codons related to IDV and SQV resistance were analyzed. After 112 weeks (median) of SQVhc, the fall in human immunodeficiency virus (HIV) type 1 RNA level from baseline was significantly greater with IDV and was inversely correlated with the number of protease substitutions. The number of substitutions also correlated with baseline CD4 cell count, HIV-1 RNA level, SQV experience, and drug susceptibility. Substitution at codon 10, which occurred only in isolates with >/=2 substitutions, was associated with blunted RNA response. IDV IC(50) correlated with HIV-1 RNA response after the switch to IDV but added little predictive power once the genotype was considered.

Adolescent↗