The objective of this study was to investigate the level of T.similar to gondii infection

in swine from southern Chile that can be associated with the ingestion of oocysts and therefore exposure to a contaminated environment. A total of 340 serum samples from swine were obtained from three commercial slaughterhouses located in the Araucania and Los Rios Regions from southern Chile. Study animals originated from local farms, mainly small commercial producers, and the meat is sold locally. Overall, 8.8% (30/340) of the samples showed T.similar to gondii-specific IgG antibodies. Of these sero-positive animals, 80% (24/30) were also URMC-099 ic50 positive for antibodies specific against the oocyst stage of selleck compound the parasite, indicating that animals had been infected recently by the ingestion of oocysts. The observed results suggest a high level of environmental contamination with oocysts on the farms of origin. In addition to the food safety problems associated with the consumption of meat from infected animals, the high level of environmental contamination on the farm represents a direct health risk for people living and/or working on these

farms. Consequently, there is a need to develop on-farm monitoring programmes and identify risk reduction strategies (food storage, water purification, rodent control and contact with cats) that are appropriate and cost-effective for informal and outdoor type of farms.”
“A chemoreduction-purge-and-trap

gas chromatographic method has been developed for the determination of trace dimethylsulfoxide (DMSO) in seawater. In the analysis procedure, DMSO was first reduced to dimethylsufide (DMS) by sodium borohydride and then the produced DMS was analyzed using the purge-and-trap technique coupled with gas chromatographic separation and flame photometric detection. Under the optimum conditions, 97% DMSO was reduced in the standard solution samples with a standard deviation of 5% (n=5). The detection limit of DMSO was 2.7 pmol of sulfur, corresponding to a concentration of 0.75 nmol/L for a 40 ml sample. This method was applied to determine the dissolved DMSO (DMSOd) and particulate DMSO (DMSOp) concentrations this website in the surface seawater of the Jiaozhou Bay, and the results showed that the DMSOd and DMSOp concentrations varied from 16.8 to 921.1 nmol/L (mean: 165.2 nmol/L) and from 8.0 to 162.4 nmol/L (mean: 57.7 nmol/L), respectively. The high concentrations of DMSOp were generally found in productive regions. Consequently, a significant correlation was found between the concentrations of DMSOp and chlorophyll a, suggesting that phytoplankton biomass might play an important role in controlling the distribution of DMSOp in the bay.

Pediatrics 2012; 129: 153-162″
“Background: Cutaneous injection-related infections (CIRI) are a primary reason individuals who inject drugs (IDU) are hospitalized. The objective of this study was to investigate determinants of hospitalization for a CIRI or related infectious complication among a cohort of supervised injection facility (SIF) users.\n\nMethods: From 1 January 1 2004 until 31 January 2008, using Cox proportional hazard regression, we examined

VE-821 cell line determinants of hospitalization for a CIRI or related infectious complication (based on ICD 10 codes) among 1083 IDU recruited from within the SIF. Length of stay in hospital and cost estimates, based on a fully-allocated costing model, was also evaluated.\n\nResults: Among hospital admissions, 49% were due to a CIRI or related infectious complication. The incidence density for hospitalization for a CIRI or related infectious complication was 6.07 per 100 person-years (95% confidence selleck intervals [CI]: 4.96 – 7.36). In the adjusted Cox proportional hazard model, being HIV positive (adjusted hazard ratio [AHR] = 1.79 [95% CI: 1.17 - 2.76]) and being referred to the hospital by a nurse at the SIF (AHR = 5.49 [95% CI: 3.48 - 8.67]) were associated with increased hospitalization. Length of stay in hospital was significantly shorter among participants referred to the hospital by a nurse at

the SIF when compared to those who were not referred (4 days [interquartile range IQR: 2-7] versus 12 days [IQR: 5-33]) even after adjustment for confounders (p = 0.001).\n\nConclusions: A strong predictor of hospitalization for a CIRI or related infectious complication was being referred to the hospital by a nurse from the SIF. This finding indicates that nurses not only facilitate

hospital utilization but may provide early intervention that prevents lengthy and expensive hospital visits for a CIRI or related infectious complication.”
“Introduction The purpose of this study was to report the feasibility of the ultrashort selleck chemicals time-to-echo (UTE) MRI technique to assess cartilaginous endplate (CEP) defects in humans in vivo and to assess their relationship with intervertebral disc (IVD) degeneration.\n\nMethods Nine volunteer subjects (mean age=43.9 years; range=22-61 years) were recruited, representing 54 IVDs and 108 CEPs. The subjects underwent T2-weighted and UTE MRI to assess for the presence and severity of IVD degeneration, and for the presence of CEP defects, respectively, from T12 to S1. IVD degeneration was graded according to the Schneiderman etal. classification on T2-weighted MRI. CEP defects were defined on UTE MRI as discontinuity of high signal over four consecutive images and were independently assessed by two observers.\n\nResults Thirty-seven out of 108 (34.

Compared to the envelope model, the inner envelope model is based on a different construction and it can produce substantial efficiency gains in situations where the envelope model offers no gains. In effect, inner envelopes open a new frontier to the way in which reducing subspaces can be used to improve efficiency in multivariate problems.”
“Recent increases in antibody titers have generated renewed interest in lower-cost continuous chromatographic processes for antibody purification. The objective

of this study was to design, build, and test a continuous countercurrent tangential chromatography system in which the resin GDC-0941 (in the form of a slurry) flows sequentially through a series of static mixers and hollow fiber membrane modules to accomplish the binding, washing, elution, stripping,

and equilibration steps in continuous operation with true countercurrent staging. Experimental studies were performed for the purification of an IgG(4) monoclonal antibody from a model feed containing bovine serum albumin and myoglobin using a protein A affinity resin. Batch uptake / desorption experiments were used in combination with critical flux filtration data to design the continuous countercurrent tangential chromatography system. The process was stable during continuous operation, providing the IgG(4) at 94% yield with greater than 97% purity. The antibody productivity was more than 40g protein per liter of resin per hour, which is significantly GSK2879552 solubility dmso greater than can be obtained using conventional packed columns. The results clearly demonstrate the potential of using continuous countercurrent tangential chromatography for large-scale antibody purification.”
“Introduction\n\nAs rates of childhood obesity rise, the nutritional content of lunches CBL0137 in vivo eaten at

school is more heavily scrutinized. We examined the association between dietary behaviors and the number of days that adolescents bring lunch to school.\n\nMethods\n\nWe analyzed cross-sectional data for 2,774 adolescents who responded to the 2005 California Health Interview Survey and reported dietary behaviors for a weekday.\n\nResults\n\nIn bivariate analyses, adolescents who typically brought their lunch from home 5 days per week ate fast food on fewer occasions; consumed fewer servings of soda, fried potatoes, and high-sugar foods; and ate more fruit and vegetables compared with adolescents who never brought their lunch to school. In linear regressions controlling for demographics, body mass index, desire to change weight, parent education, and adult presence after school, students who typically brought their lunch to school 5 days per week ate fast food 0.35 fewer times and consumed 0.35 fewer servings of soda, 0.10 fewer servings of fried potatoes, 0.25 fewer servings of high-sugar foods, and 0.95 more servings of fruit and vegetables per day compared with students who never brought their lunch to school.

The formation of the [Ru-II([9]aneS(3))(HCpz(3))](2+) and [Ru-II([9]aneS(3))(HCpz(3))Cl](+) ions by electrospraying solutions of [Ru-II([9]aneS(3))(dmso)Cl-2] (dmso = dimethylsulfoxide) and HCpz(3) in water/methanol was also studied.\n\nFragmentation of the [Ru-II([9]aneS(3))(HCpz(3))](2+) ions by losses from the[9]aneS(3) ligand seems to point to a k(3) strained coordination this website mode, whereas fragmentation of the [Ru-II([9]aneS(3))(HCpz(3))Cl](+) points to a less strained complex and to two isomers: the complex [Ru-II([9]aneS(3))(HCpz(3))Cl](+) and the ion pair [Ru-II([9]aneS(3))(HCpz(3))+Cl](+). Further support for the ion pair

hypothesis is the strong increase of the relative abundance of the [Ru-II([9]aneS(3))(HCpz(3))+PF6](+) ion, m/z 641, formed from solutions of the [Ru-II(k(3)-[9]aneS(3))(k(3)-HCpz(3))](Cl)PF6 and [Ru-II(k(3)-[9]aneS(3))(k(3)-HCpz(3))](PF6)(2) complexes, after 16 h.\n\nThe high stability of the ion pairs indicates that they may be inner sphere ion pairs and that AZD4547 either [9]aneS(3) or HCpz(3) changes from a k(3) to a k(2) coordination mode. The results support an equilibrium

between a full k(3)-[9]aneS(3)/k(3)-HCpz(3) complex and a k(2) + k(3) + Cl/PF6 ion pair. (C) 2010 Elsevier B.V. All rights reserved.”
“AimsSessile marine invertebrates engage in a diverse array of beneficial interactions with bacterial symbionts. One feature of some of these relationships is the presence of bioactive natural products that can defend the holobiont from predation, competition or disease. In this study, we investigated the antimicrobial activity and microbial community of a common temperate sponge from coastal North Carolina. Methods and ResultsThe sponge was identified as a member of the genus Haliclona, a prolific source of bioactive natural products, based on its 18S rRNA gene sequence. The crude chemical extract and methanol partition had broad activity against the assayed Gram-negative and Gram-positive pathogenic bacteria. Further fractionation resulted in two groups of compounds with differing antimicrobial

activity, primarily against Gram-positive AZD6094 cell line test organisms. There was, however, notable activity against the Gram-negative marine pathogen, Vibrio parahaemolyticus. Microbial community analysis of the sponge and surrounding sea water via denaturing gradient gel electrophoresis (DGGE) indicates that it harbours a distinct group of bacterial associates. ConclusionsThe common temperate sponge, Haliclona sp., is a source of multiple antimicrobial compounds and has some consistent microbial community members that may play a role in secondary metabolite production. Significance and Impact of the StudyThese data suggest that common temperate sponges can be a source of bioactive chemical and microbial diversity. Further studies may reveal the importance of the microbial associates to the sponge and natural product biosynthesis.

The transcriptional activity of rs4648068 (A bigger than G) by dual-Luciferase reporter assay suggested that the luciferase activity of homozygote group (pGL3-GG) was GNS-1480 in vitro greater than that of the control (pGL3-AA), especially at the stimulation of LPS. We found that the luciferase activity was also influenced by pGL3-GG levels. The effects

of NFKB1 rs4648068 were enhanced by rs4648065 on the transduced cells. The interaction between NFKB1 promoter nucleotide sequence and C/EBP beta was regulated by the functional SNP rs4648068 in SGC-7901 cells. Our data indicated that the transduction of pGL3 expression plasmid pGL3-GG-NFKB improved the proliferation and motility of gastric cancer cells. Correspondingly, the homozygote GG of SNP rs4648068 strengthened the transcriptional activity of NFKB1 and influenced the cell biological activity. Conclusion: The transcriptional activity of NFKB1 was associated with SNP rs4648068, and this functional SNP site has the important effects

on cell proliferation and Screening Library cost motility.”
“Rationale: The impact of REM-predominant sleep-disordered breathing (SDB) on sleepiness, quality of life (Q0L), and sleep maintenance is uncertain.\n\nObjective: To evaluate the association of SDB during REM sleep with daytime sleepiness, health-related QOL, and difficulty maintaining sleep, in comparison to their association with SDB during non-REM sleep in a community-based cohort.\n\nMethods: Cross-sectional analysis of 5,649 Sleep Heart Health Study participants (mean age 62.5 [SD = 10.9], 52.6% women, 22.6% ethnic minorities). SDB during REM and non-REM sleep was quantified using polysomnographically derived apnea-hypopnea index in REM (AHI(REM)) and non-REM (AHI(NREM)) sleep. Sleepiness, sleep maintenance, and QOL

were respectively quantified using the Epworth Sleepiness Scale (ESS), the Sleep Heart Health Study Sleep Habit Questionnaire, and the physical and mental composites scales of the Medical Outcomes Study Short PRT062607 solubility dmso Form (SF)-36.\n\nMeasurements and Main Results: AHI(REM) was not associated with the ESS scores or the physical and mental components scales scores of the SF-36 after adjusting for demographics, body mass index, and AHI(NREM). AHI(REM) was not associated with frequent difficulty maintaining sleep or early awakening from sleep. AHI(NREM) was associated with the ESS score (beta = 0.25; 95% confidence interval [CI], 0.16 to 0.34) and the physical (beta = 0.12; 95% CI, -0.42 to 0.01) and mental (beta = 0.20; 95% CI, 0.20 to 0.01) components scores of the SF-36 adjusting for demographics, body mass index, and AHI(REM).\n\nConclusions: In a community-based sample of middle-aged and older adults, REM-predominant SDB is not independently associated with daytime sleepiness, impaired health-related QOL, or self-reported sleep disruption.

Finally, a refined pharmacophore model was generated using the most active compounds 2, 12c and 22c via application of HipHop program. (C) 2013 find more Elsevier Masson SAS. All rights reserved.”
“Introduction: Microsporidia constitute the most common black fly pathogens, although the species’ diversity, seasonal occurrence and transmission mechanisms remain poorly understood. Infections by this agent

are often chronic and non-lethal, but they can cause reduced fecundity and decreased longevity. The objective of this study was to identify microsporidia infecting Simulium (Chirostilbia) pertinax (Kollar, 1832) larvae from Caraguatatuba, State of Sao Paulo, Brazil, by molecular and morphological characterization. Methods: Larvae were collected at a single point in a stream in a rural area of the city and were kept under artificial aeration until analysis. Polydispyrenia spp. infection was characterized by the presence of Tipifarnib at least 32 mononuclear spores measuring 6.9 +/- 1.0 x 5.0 +/- 0.7 mu m in persistent sporophorous vesicles. Similarly, Amblyospora spp. were characterized

by the presence of eight uninucleate spores measuring 4.5 x 3.5 mu m in sporophorous vesicles. Results: The molecular analysis confirmed the presence of microsporidian DNA in the 8 samples (prevalence of 0.51%). Six samples (Brazilian larvae) were related to Polydispyrenia simulii and Caudospora palustris reference sequences but in separate clusters. One sample was clustered with Amblyospora spp. Edhazardia aedis was the positive control taxon. Selleckchem Epigenetic inhibitor Conclusions: Samples identified as Polydispyrenia spp. and Amblyospora spp. were grouped with P. simulii and Amblyospora spp.,

respectively, corroborating previous results. However, the 16S gene tree showed a considerable distance between the black fly-infecting Amblyospora spp. and the mosquito-infecting spp. This distance suggests that these two groups are not congeneric. Additional genomic region evaluation is necessary to obtain a coherent phylogeny for this group.”
“Many cancer drugs are toxic to cells by activating apoptotic pathways. Previous studies have shown that mitochondria have key roles in apoptosis in mammalian cells, but the role of mitochondrial DNA (mtDNA) copy number variation in the pathogenesis of tumor cell apoptosis remains largely unknown. We used the HEp-2, HNE2, and A549 tumor cell lines to explore the relationship between mtDNA copy number variation and cell apoptosis. We first induced apoptosis in three tumor cell lines and one normal adult human skin fibroblast cell line (HSF) with cisplatin (DDP) or doxorubicin (DOX) treatment and found that the mtDNA copy number significantly increased in apoptotic tumor cells, but not in HSF cells. We then downregulated the mtDNA copy number by transfection with shRNA-TFAM plasmids or treatment with ethidium bromide and found that the sensitivity of tumor cells to DDP or DOX was significantly increased.

Because EC function is influenced by their origin, biomaterial surface chemistry and hemodynamics,

these issues must be considered to optimize implant performance. In this review, we examine the recent in vivo use of endothelialized biomaterials and discuss the fundamental issues that must be considered when engineering functional vasculature.”
“A protocol to attain high-resolution single-particle reconstructions is presented. The protocol is the concatenation of two procedures: one to obtain an ab AZD8055 mw initio low-resolution reconstruction, the other to determine a fixed point of the consecutive applications of fast projection matching and 3D reconstruction. It is a reciprocal space formulation where the Fourier coefficients Selleckchem JQ-EZ-05 of the 3D scattering density are expressed in terms of symmetry adapted functions and the 2D particle images are represented by their Fourier-Bessel transforms.

The new protocol shows advantages in terms of speed and accuracy when compared to other methods currently in use. We illustrate its performance as applied to high-resolution cryo-electron micrographs of rotavirus. (C) 2010 Elsevier Inc. All rights reserved.”
“Purpose: Histone deacetylase inhibitors (HDACi) are actively explored as new-generation epigenetic drugs but have low efficacy in cancer monotherapy. To reveal new mechanism for combination therapy, we show that HDACi induce cell death but simultaneously activate tumor-progressive genes to ruin therapeutic efficacy. Combined treatments

to target tumorigenesis and HDACi-activated metastasis with low toxic modalities could develop new strategies for long-term cancer therapy.\n\nExperimental Design: Because metastasis is the major cause of cancer mortality, we measured cell migration activity and profiled metastasis-related gene expressions in HDACi-treated cancer cells. We developed low toxic combination modalities targeting tumorigenesis and HDACi-activated KYT-0353 metastasis for preclinical therapies in mice.\n\nResults: We showed that cell migration activity was dramatically and dose dependently enhanced by various classes of HDACi treatments in 13 of 30 examined human breast, gastric, liver, and lung cancer cell lines. Tumor metastasis was also enhanced in HDACi-treated mice. HDACi treatments activated multiple PKCs and downstream substrates along with upregulated proapoptotic p21. For targeting tumorigenesis and metastasis with immediate clinical impact, we showed that new modalities of HDACi combined drugs with PKC inhibitory agent, curcumin or tamoxifen, not only suppressed HDACi-activated tumor progressive proteins and cell migration in vitro but also inhibited tumor growth and metastasis in vivo.\n\nConclusion: Treatments of different structural classes of HDACi simultaneously induced cell death and promoted cell migration and metastasis in multiple cancer cell types.

This metal-organic framework has an active domain that expresses good and selective uptake of neutral and positively charged electron-poor aromatic guests, which effect color changes of the cubic crystals from faint yellow to deep orange, arising from charge transfer between the guests and active domain of P5A-MOE-1.”
“BACKGROUND: Spray-drying techniques are commonly utilized in the pharmaceutical, dairy, and animal feed industries for processing liquids into powders but have

not been applied to human blood products. Spray-dried protein products are known to maintain stability during storage at room temperature.\n\nSTUDY DESIGN AND METHODS: Plasma units collected at the donor facility were shipped overnight at room temperature to a processing

facility where single-use spray drying occurred. After 48 hours’ storage at room temperature, the spray-dried plasma product was split in two and rehydrated Autophagy signaling pathway inhibitors with 1.5% glycine or deionized water and assayed for chemistry analytes and coagulation factors. Matched fresh-frozen plasma was analyzed in parallel as controls.\n\nRESULTS: Reconstitution was achieved for both rehydration groups within 5 minutes (n = 6). There was find more no significant intergroup difference in recovery for total protein, albumin, immunoglobulin (Ig) G, IgA, and IgM (96% or higher). With the exception of Factor VIII (58%), the recovery of clotting factors in the glycine reconstituted products ranged from 72% to 93%. Glycine reconstitution

was superior to deionized water.\n\nCONCLUSION: www.selleckchem.com/products/ABT-263.html We documented proteins and coagulation activities were recovered in physiologic quantities in reconstituted spray-dried plasma products. Further optimization of the spray-drying method and reconstitution fluid may result in even better recoveries. Spray drying is a promising technique for preparing human plasma that can be easily stored at room temperature, shipped, and reconstituted. Rapid reconstitution of the microparticles results in a novel plasma product from single donors.”
“Background and objective:\n\nTherapeutic thoracentesis (TT) is required in patients with refractory pleural effusions and impaired oxygenation. In this study, the relationship between pleural space elastance (PE) and changes in oxygenation after TT was investigated in ventilated patients with heart failure and transudative pleural effusions.\n\nMethods:\n\nTwenty-six mechanically ventilated patients with heart failure and significant transudative effusions, who were undergoing TT, were studied. The effusion was drained as completely as possible, with monitoring of pleural liquid pressure (Pliq) and chest symptoms. The volume of effusion removed, the changes in Pliq during TT, PE and arterial blood gases before and after TT were recorded.\n\nResults:\n\nThe mean volume of effusion removed was 1011.9 +/- 58.2 mL. The mean Pliq decreased from 14.5 +/- 1.

Here, using a morpholino oligonucleotide (MO)-based loss-of-function strategy, we have generated a model of NAIC in the zebrafish, Danio rerio. Zebrafish Cirhin shows substantial homology to the human homolog, and cirh1a mRNA is

expressed in developing hepatocytes and biliary epithelial cells. Injection of two independent MOs directed against cirh1a at the one-cell stage causes defects in canalicular and biliary morphology in 5 dpf larvae. In addition, 5 dpf Cirhin-deficient larvae have dose-dependent defects in hepatobiliary function, as assayed by the metabolism of an ingested fluorescent lipid reporter. Previous yeast and in vitro studies have shown that defects in ribosome biogenesis cause stabilization and nuclear accumulation of p53, which in turn causes p53-mediated cell cycle GSK126 purchase arrest and/or apoptosis. Thus, the nucleolus appears to function as a cellular stress sensor in some cell types. In accordance with this hypothesis, transcriptional targets of p53 are upregulated in Cirhin-deficient zebrafish check details embryos, and defects in biliary function seen in Cirhin-deficient larvae are completely abrogated by mutation of tp53. Our data provide the first in vivo evidence of a role for Cirhin in biliary development, and support the hypothesis that congenital

defects affecting ribosome biogenesis can activate a cellular stress response mediated by p53.”
“Purpose of review\n\nIn this review, we focus on the clinical features, diagnosis, outcome and management of bacterial community-acquired pneumonia (BCAP) in HIV-infected patients, with particular attention to the most recent findings

in this area.\n\nRecent findings\n\nClinical features of BCAP are often atypical in HIV-infected individuals, especially when liver cirrhosis is also present. Streptococcus pneumoniae is the most common causative agent and is frequently associated with bacteriemic disease even in low-risk patients according to pneumonia severity index. An etiologic diagnosis is obtained in selleck products an average 35% of cases with standard culture methods. In such conditions, urinary antigen test for S. pneumoniae identification may help in reaching a rapid and etiologic diagnosis. CD4 cell count should be carefully considered in HIV patients with BCAP. In consideration of their high mortality risk, patients with a CD4 cell count of less than 200 cells/mu l should be hospitalized, whereas those with a CD4 cell count of at least 200 cells/mu l could be managed according to pneumonia severity index score. Empiric antibiotic therapy should include a combination of a beta-lactam and a macrolide or a respiratory fluoroquinolone alone. Finally, prevention strategies should include lifestyle modification, highly active antiretroviral therapy access and adherence programs and the implementation of pneumococcal vaccination.

Indeed, iPS cells have been created recently using chemical compounds only. iPSCs are thought to display subtle genetic and epigenetic variability; this variability is not random, but occurs at hotspots across the genome. Here we discuss the progress and current perspectives in the field. Research into the reprogramming process today will pave the way

for great advances in regenerative medicine in the future.”
“To review our current knowledge of the pathologic bone metabolism in otosclerosis and to discuss the possibilities of non-surgical, pharmacological intervention. Otosclerosis has been suspected to be associated with defective measles virus infection, local inflammation and consecutive bone deterioration in the human otic capsule. In the early stages of otosclerosis, different pharmacological agents may delay the progression or prevent check details further deterioration of the disease and consecutive hearing loss. Although effective anti-osteoporotic drugs have become available, the use of sodium fluoride and bisphosphonates in otosclerosis has not yet been successful. Bioflavonoids may relieve tinnitus due to otosclerosis, click here but there is no data

available on long-term application and effects on sensorineural hearing loss. In the initial inflammatory phase, corticosteroids or non-steroidal anti-inflammatory drugs may be effective; however, extended systemic application may lead to serious side effects. Vitamin D administration may have effects on the pathological bone loss, as well as on inflammation. No information has been reported on the use of immunosuppressive drugs. Anti-cytokine targeted biological therapy, however, may be feasible. Indeed, one study on the local administration of infliximab has been reported. Potential targets of future therapy may include osteoprotegerin, RANK ligand, cathepsins Dinaciclib and also the Wnt-beta-catenin pathway. Finally, anti-measles vaccination may delay the progression of the disease and potentially decrease the number of new cases. In conclusion,

stapes surgery remains to be widely accepted treatment of conductive hearing loss due to otosclerosis. Due to lack of solid evidence, the place of pharmacological treatment targeting inflammation and bone metabolism needs to be determined by future studies.”
“Blueberry juice processing by-products are a rich source of procyanidins, which comprise a group of compounds shown to possess numerous health benefits, including protection against coronary heart disease, type II diabetes, and obesity. Most of the procyanidins present in blueberry pomace, however, are large molecular weight compounds that are poorly absorbed and show weak bioactivity compared to the smaller molecular weight monomers and dimers.