Examining the epidemiology and microbiology of Clostridium difficile carriage in elderly patients and residents of a healthcare facility in southern Ontario, Canada.

BACKGROUND: Whereas Clostridium difficile has been extensively studied in acute care facilities (ACFs), there is limited information about long-term care facilities (LTCFs), despite the high occurrence of putative risk factors (e.g. age, antimicrobial use, healthcare system contact). AIM: To evaluate C. difficile colonization in elderly patients and residents from one ACF and its associated LTCF. METHODS: Stool swabs were collected from 884 LTCF and elderly (>65 years) hospital patients. Selective culture, polymerase chain reaction ribotyping and toxin gene characterization were performed. FINDINGS: C. difficile was isolated from 92/410 (22.4%) ACF and 89/474 (18.8%) LTCF samples. Ribotypes 027 (35%) and 020 (10.4%) predominated in the LTCF whereas ribotypes AI-82/1 (20.7%) and ribotype O (14.1%) predominated at the ACF (P = 0.031). In the LTCF, C. difficile colonization was associated with a history of proton pump inhibitor (PPI) use, and the interaction terms of male residents with prior medical leave of absence, and a prior history of C. difficile infection (CDI) combined with fluoroquinolone use. In the ACF, C. difficile colonization was associated with length of stay, feeding through a tube, antibiotic use, immunosuppressive therapy and VRE colonization, as well as the interaction terms for cephalosporin and fluoroquinolone use, prior CDI and cephalosporin use, and prior CDI and fluoroquinolone use. CONCLUSION: C. difficile colonization by ACF and LTCF residents was common, despite a low apparent incidence of CDI. The association with PPI provides further evidence of the potential importance of this widely used drug class in C. difficile colonization. Wide genetic diversity was present, highlighting the likelihood of multiple unidentified routes of C. difficile acquisition.

A clinical algorithm for wound biofilm identification.

Recognition of the existence of biofilm in chronic wounds is increasing among wound care practitioners, and a growing body of evidence indicates that biofilm contributes significantly to wound recalcitrance. While clinical guidelines regarding the involvement of biofilm in human bacterial infections have been proposed, there remains uncertainty and lack of guidance towards biofilm presence in wounds. The intention of this report is to collate knowledge and evidence of the visual and indirect clinical indicators of wound biofilm, and propose an algorithm designed to facilitate clinical recognition of biofilm and subsequent wound management practices.

A next-generation antimicrobial wound dressing: a real-life clinical evaluation in the UK and Ireland.

OBJECTIVE: To assess the effectiveness of a new, next-generation antimicrobial dressing (NGAD; AQUACEL Ag+ EXTRA dressing) in managing wound exudate, infection and biofilm, and facilitating progression toward healing. METHOD: Clinicians from the UK and Ireland selected stalled or deteriorating wounds that were considered to be compromised by infection and/or biofilm. Only the primary dressing was replaced by the NGAD, for up to 4 weeks or as deemed clinically appropriate; otherwise, standard protocols of care were used. Evaluation forms captured the baseline and final assessment characteristics of wound status, exudate levels, skin health, wound bed appearance, signs of infection and biofilm, and wound dimensions. RESULTS: In all, 29 wounds were suitable for inclusion in the final analysis. Following the NGAD evaluation, wound statuses were shifted from stagnant/deteriorating to mainly improved, exudate levels were shifted from moderate/high to moderate/low, and skin health was improved in 20 wounds (69%). Wound bed tissue types were shifted from largely suspected biofilm/sloughy tissue (76%) to largely granulation tissue (53%). All signs of clinical infection were reduced in average frequency, with biofilm suspicion falling from 76% to 45% of the cases. The median management period with the NGAD was 4.5 weeks, after which 26 wounds (90%) became smaller in size and 10 wounds (34%) completely healed. CONCLUSION: This real-life clinical evaluation of the NGAD suggests that its successful management of exudate, infection and biofilm is generally accompanied by notable improvements in wound health and size, and in some cases, complete healing. DECLARATION OF INTEREST: The authors are all employed by ConvaTec Ltd. but have no other conflict of interest to declare. Dressings were provided to the clinicians free of charge.

Super-resolution microscopy as a potential approach to diagnosis of platelet granule disorders.

BACKGROUND: Many platelet functions are dependent on bioactive molecules released from their granules. Deficiencies of these granules in number, shape or content are associated with bleeding. The small size of these granules is such that imaging them for diagnosis has traditionally required electron microscopy. However, recently developed super-resolution microscopes provide sufficient spatial resolution to effectively image platelet granules. When combined with automated image analysis, these methods provide a quantitative, unbiased, rapidly acquired dataset that can readily and reliably reveal differences in platelet granules between individuals. OBJECTIVE: To demonstrate the ability of structured illumination microscopy (SIM) to efficiently differentiate between healthy volunteers and three patients with Hermansky-Pudlak syndrome. METHODS: Blood samples were taken from three patients with Hermansky-Pudlak syndrome and seven controls. Patients 1-3 have gene defects in HPS1, HPS6 and HPS5, respectively; all controls were healthy volunteers. Platelet-rich plasma was isolated from blood and the platelets fixed, stained for CD63 and processed for analysis by immunofluorescence microscopy, using a custom-built SIM microscope. RESULTS: SIM can successfully resolve CD63-positive structures in fixed platelets. A determination of the number of CD63-positive structures per platelet allowed us to conclude that each patient was significantly different from all of the controls with 99% confidence. CONCLUSIONS: A super-resolution imaging approach is effective and rapid in objectively differentiating between patients with a platelet bleeding disorder and healthy volunteers. CD63 is a useful marker for predicting Hermansky-Pudlak syndrome and could be used in the diagnosis of patients suspected of other platelet granule disorders.

A real-life clinical evaluation of a next-generation antimicrobial dressing on acute and chronic wounds.

OBJECTIVE: To assess the effectiveness of a new, next-generation antimicrobial dressing (AQUACEL Ag+ dressing) in facilitating healing in a variety of hard-to-heal wounds that may have been compromised by infection and/or biofilm. METHOD: This was an international, multi-centred, real-life, non-randomised evaluation involving patients with a wide variety of slow-, non-healing or deteriorating chronic and acute wounds. There were no strict inclusion or exclusion criteria and the clinicians were asked to use their discretion in the selection of patients. The clinicians continued to use their standard protocol of care but replaced their existing primary wound-contact dressing with the next-generation antimicrobial dressing (NGAD) for up to 4 weeks. Clinicians could extend the treatment period if this was deemed clinically appropriate. Baseline assessments included wound bed characteristics, exudate level, indicators of wound biofilm, and signs and symptoms of infection. At the final assessment, the investigators reported the wound size, wound bed characteristics, and exudate level. RESULTS: A total of 121 patients were recruited into the original evaluation, of which eight were excluded for incomplete data sets. Most wounds (73; 64%) were either venous leg ulcers (59; 52%) or diabetic foot ulcers (14; 12%). At baseline, the wounds of (26; 23%) patients were slowly improving, 65 were stagnant (58%) and 22 (19%) were deteriorating. Just under three-quarters (74%) of the wounds had suspected biofilm (criteria including failure of a wound to heal, lack of response to topical and systemic antimicrobial agents, or the presence of slimy substances on the wound surface). Following the evaluations, the average wound closure achieved for all wounds was 72.6%, 19 (17%) wounds healed, 47 (42%) achieved at least 90% wound closure, and 71 (63%) achieved at least 75% closure. The average treatment period was 4.1 weeks; 35 wounds were treated with the dressing for more than 4 weeks. Cost analysis indicated that potential antimicrobial dressing cost reductions of approximately 30% were realised using the NGAD. CONCLUSION: This real-life, non-randomised evaluation provides encouraging evidence that the NGAD may have a role to play in facilitating wound progression towards healing by helping to eliminate the biofilm barrier. DECLARATION OF INTEREST: M. Walker, D. Metcalf, D. Parsons and P. Bowler are all employees of ConvaTec Ltd. Aysha Mendes da Mata is an independent writer and Annemarie Brown is an independent clinician, both received a fee and support from MA Healthcare to write up the evaluation using data supplied by ConvaTec.

A clinical algorithm for wound biofilm identification.

Recognition of the existence of biofilm in chronic wounds is increasing among wound care practitioners, and a growing body of evidence indicates that biofilm contributes significantly to wound recalcitrance. While clinical guidelines regarding the involvement of biofilm in human bacterial infections have been proposed, there remains uncertainty and lack of guidance towards biofilm presence in wounds. The intention of this report is to collate knowledge and evidence of the visual and indirect clinical indicators of wound biofilm, and propose an algorithm designed to facilitate clinical recognition of biofilm and subsequent wound management practices.

Clostridium difficile in vegetables, Canada.

BACKGROUND: Clostridium difficile is an important gastrointestinal pathogen of humans and animals. It has been isolated from various foods, including meat and ready-to-eat salads, and concern has been expressed regarding food as a possible source of human C. difficile infection (CDI). AIMS: We sought to isolate C. difficile from a variety of vegetables obtained from local grocery stores and to characterize these isolates. MATERIALS AND METHODS: Vegetables were purchased from 11 different grocery stores in Guelph, Ontario, Canada between May and August 2009. Enrichment culture was performed and isolates were characterized by ribotyping, PFGE, toxinotyping and PCR detection of toxin genes. RESULTS: Clostridium difficile was isolated from 4.5% (5/111) of retail vegetables. Two different ribotypes and two different toxinotypes were identified. Three isolates were ribotype 078/NAP 7/toxinotype V, possessing all three toxin genes. The other two isolates shared a ribotype with a toxigenic strain previously found in humans with CDI in this region. DISCUSSION: Contamination of vegetables was found at relatively low levels, however, all isolates were toxigenic and belonging to ribotypes previously associated with CDI. CONCLUSIONS: Contamination of vegetables with CDI-associated isolates can occur and although the implications for food safety practices remain elusive, the presence of toxigenic isolates suggests vegetables could be a source of C. difficile in humans.

Characters of aerated compost tea from immature compost that limit colonization of bean leaflets by Botrytis cinerea.

AIMS: The aim was to produce and characterize an aerated compost tea (ACT) that suppressed growth of the plant pathogen Botrytis cinerea. METHODS AND RESULTS: Three different open-windrow composts were sampled weekly from the early secondary mesophilic stage until maturity. Each 10kg of compost sample was extracted in 30 l of aerated water for 24, 48 or 72h. Relative to water, all batches of ACT applied to detached bean leaflets reduced lesion development following single-point inoculations of B. cinerea. There was a significant linear, inverse relationship between the internal windrow temperature of compost (≤51°C) used to prepare ACT and the extent of lesion development. Bacterial diversity in ACTs from one windrow was highest using compost sampled at 48°C. The compost weight-to-water volume ratios of 1:3, 1:10 or 1:30, using compost sampled from a fourth windrow at 50°C, also produced ACTs that reduced the growth of B. cinerea on bean leaflets. The '1 : 3' ACT, and to a lesser degree the same ACT filtered to remove micro-organisms, inhibited the germination of B. cinerea conidia. CONCLUSIONS: ACT produced using the methods reported here suppressed the growth of B. cinerea on bean leaflets, with an abundant and diverse microbial community likely to contribute to pathogen suppression. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of the use of immature compost to produce a pathogen-suppressive ACT, suggesting that compost stage is an important production variable.

Two distinct types of murine blast colony-forming cells are multipotential hematopoietic precursors.

Two types of blast colonies can be stimulated to develop in semisolid agar cultures of murine bone marrow cells. Typically, these are either multicentric colonies stimulated by stem cell factor (SCF) plus interleukin-6 (IL-6) or dispersed colonies stimulated by Flt3 ligand (FL) plus IL-6. Both types of blast colony-forming cells (BL-CFCs) can generate large numbers of lineage-committed granulocyte-macrophage progenitor cells and exhibit some capacity for self-generation and the formation of eosinophil and megakaryocyte progenitor cells. However, the two populations of BL-CFCs are largely distinct and partially separable by fluorescence-activated cell sorting and are distinguished by differing capacity to form granulocyte-committed progeny. Both types of BL-CFCs can generate dendritic cells and small numbers of lymphocytes but the FL-responsive BL-CFCs have a greater capacity to form both B and T lymphocytes. Both types of blast colonies offer remarkable opportunities to analyze multilineage commitment at a clonal level in vitro.

Perineal hernia after proctectomy: prevalence, risks, and management.

PURPOSE: Perineal hernias are infrequent complications of abdominoperineal operations with estimated historic prevalences (from the era where the perineal wound was left open) ranging from 0.6 to 7 percent. The purpose of this study was to identify the modern prevalence of postoperative perineal hernias, factors that may contribute to their development, and examine the methods of repair. METHODS: The Mayo Clinic patient database (1990-2000) was interrogated for the following data identifiers: incisional hernia, perineal hernia, abdominoperineal resection, proctocolectomy, and partial or total pelvic exenteration. All surviving patients were followed up to December 2005. The retrieved patient data was retrospectively analyzed. RESULTS: Of a total of 3,761 patients who underwent abdominoperineal resection (including nonrestorative proctocolectomy and pelvic exenteration) during the study period, 8 developed a perineal hernia (5 females). The median age at hernia presentation was 76 (range, 69-84) years, representing a median interval of 22 (range, 1-60) months from the original operation. All were smokers (> or =15 pack years) and five had received chemoradiotherapy for their original diagnosis. The commonest prevalence was found in patients who had undergone abdominoperineal resection (5/1,266) or pelvic exenteration (2/1,334). Only 1 of 1,161 patients developed a perineal hernia after proctocolectomy despite most being on perioperative immunosuppression for inflammatory bowel disease. Abdominal exploration and repair was performed in four patients whereas four underwent perineal repair (2 of each with mesh). None have recurred with a median follow-up of 36 (range, 6-60) months. CONCLUSIONS: Perineal hernias are rare complications of abdominoperineal surgery with a more common prevalence after cancer operations. Smoking and chemoradiotherapy, but not corticosteroid immunosuppression, may be factors. The abdominal approach has advantages over the perineal approach, but both are suitable with good medium-term results.

Genetic deletion of murine SPRY domain-containing SOCS box protein 2 (SSB-2) results in very mild thrombocytopenia.

The SSB family is comprised of four highly homologous proteins containing a C-terminal SOCS box motif and a central SPRY domain. No function has yet been ascribed to any member of this family in mammalian species despite a clear role for other SOCS proteins in negative regulation of cytokine signaling. To investigate its physiological role, the murine Ssb-2 gene was deleted by homologous recombination. SSB-2-deficient mice were shown to have a reduced rate of platelet production, resulting in very mild thrombocytopenia (25% decrease in circulating platelets). Tissue histology and other hematological parameters were normal, as was the majority of serum biochemistry, with the exception that blood urea nitrogen (BUN) levels were decreased in mice lacking SSB-2. Quantitative analysis of SSB mRNA levels indicated that SSB-1, -2, and -3 were ubiquitously expressed; however, SSB-4 was only expressed at very low levels. SSB-2 expression was observed in the kidney and in megakaryocytes, a finding consistent with the phenotype of mice lacking this gene. Deletion of SSB-2 thus perturbs the steady-state level of two tightly controlled homeostatic parameters and identifies a critical role for SSB-2 in regulating platelet production and BUN levels.

Effect of Inoculum Density of Sclerotium cepivorum on the Ability of Trichoderma koningii to Suppress White Rot of Onion.

Amendment of soil with Trichoderma koningii strain Tr5 grown on autoclaved white millet grain provided between 63 and 79% control of white rot of onion when added to soil containing 10, 25, 50, or 100 sclerotia of Sclerotium cepivorum per kilogram of soil at the time of onion seed sowing. There was no significant difference in the proportion of S. cepivorum infections suppressed among the different sclerotial density treatments. Rhizosphere colonization by T. koningii Tr5 was assessed by incubating onion roots sampled from plants growing in soil with the appropriate density of sclerotia, on a Trichoderma selective medium (Rose bengall-Allisan-streptomycin-Previcur agar) developed for the purpose of the study. Trichoderma spp. isolated were typed by comparison of culture morphology as well as polygalacturonase (PG) (EC 3.2.1.15) and pectinesterase (PE) (EC 3.1.1.11) isozyme profiles to the series of one PG and two PE isozymes known to be produced by T. koningii Tr5. The method was used successfully to assess rhizosphere colonization. Three rates of a millet grain formulation colonized by T. koningii Tr5 were added to soil (1,590, 3,180, and 4,770 kg/ha). At the lowest of these rates, 97% of roots were found to be colonized by isolates which could not be distinguished from T. koningii Tr5, whereas 8% of the roots from nontreated controls were colonized by such isolates. An objective of the study was to determine whether the ability of T. koningii Tr5 to suppress S. cepivorum infections was influenced by increased concentrations of both S. cepivorum sclerotia and T. koningii Tr5-colonized millet grain, and it was found that no further improvements in the percentage of disease suppression were recorded as a result of adding T. koningii Tr5-colonized millet to the soil at more than 1,590 kg/ha at any of the sclerotium concentrations tested.

A search for virulence genes of Haemophilus parasuis using differential display RT-PCR.

Although Haemophilus parasuis is an important bacterial pathogen of swine, little is known about its pathogenesis or why some strains seem to be more virulent than others. Therefore, we used differential display reverse transcription-polymerase chain reaction (DDRT-PCR) to search for virulence-associated genes in a pathogenic serotype 5 strain, H. parasuis 1185. Gene expression was evaluated following growth in conditions chosen to begin to approximate those found in the upper respiratory tract and those encountered by the organism during acute infection. Seven different differentially expressed gene fragments were identified in cells grown at 40 degrees C in both the presence and absence of swine serum. Based on the deduced amino acid sequences, the most strongly up-regulated genes were homologs of fadD (a fatty acyl-CoA synthetase), apaH (diadenosine tetraphosphatase), pstI (enzyme I of the phosphoenolpyruvate-protein phosphotransferase system), and cysK (cysteine synthetase). Homologs of Std (Na(+)- and Cl(-)-dependent ion transporter), HSPG (a mammalian basement membrane-specific heparin sulphate core protein precursor) and PntB (pyridine nucleotide transhydrogenase) were also up-regulated, but to a much lower extent. Sequences homologous to all of the differentially expressed genes were detected in the reference strains of all 15 H. parasuis serotypes. This is the first report of a global search for virulence factors of H. parasuis.

The SOCS box of suppressor of cytokine signaling-1 is important for inhibition of cytokine action in vivo.

Suppressor of Cytokine Signaling-1 (SOCS-1) is an essential physiological inhibitor of IFN-gamma signaling. Mice lacking this gene die in the early postnatal period from a disease characterized by hyperresponsiveness to endogenous IFN-gamma. The SOCS box is a C-terminal domain shared with over 30 other proteins that links SOCS proteins to an E3 ubiquitin ligase activity and the proteasome, but whether it contributes to inhibition of cytokine signaling is currently disputed. We have deleted only the SOCS box of the SOCS-1 gene in mice and show that such mice have an increased responsiveness to IFN-gamma and slowly develop a fatal inflammatory disease. These results demonstrate that deletion of the SOCS box leads to a partial loss of function of SOCS-1.

Production of colony-stimulating factors and IL-5 by organs from three types of mice with inflammatory disease due to loss of the suppressor of cytokine signaling-1.

Organs from neonatal mice dying from IFN-gamma-dependent inflammatory disease initiated by loss of the gene encoding the suppressor of cytokine signaling-1 (SOCS-1) had a normal capacity to produce G-CSF in vitro but a reduced capacity to produce GM-CSF, most evident with the lung, and some reduction in the production of M-CSF by muscle tissue. In contrast, organs from mice lacking the genes for both SOCS-1 and IFN-gamma had a normal capacity to produce CSFs. Organs from young adult mice dying with polymyositis and myocarditis that lacked SOCS-1 but were heterozygous for IFN-gamma had a normal capacity to produce GM-CSF and M-CSF, but muscle tissue produced significantly increased amounts of G-CSF and IL-5 with IL-5 production also being elevated for the salivary gland, thymus, and heart. Loss of the IFN-gamma gene alone had no impact on organ production of these cytokines in vitro. In none of the inflammatory disease models was IL-3 production detected. The SOCS-1 protein appears to have no direct influence on the cellular production of these cytokines and the abnormalities observed either depend on the coaction of IFN-gamma, or more likely, are linked with the invasion and destruction of tissue by T lymphocytes, macrophages, eosinophils, and neutrophils. The ability of local organs to produce these proinflammatory cytokines could contribute to the development and progression of these inflammatory lesions.

Chemotherapy for a patient with advanced non-small-cell lung cancer during pregnancy: a case report and a review of chemotherapy treatment during pregnancy.

BACKGROUND: Lung cancer is the most common cause of cancer death in women in the USA. Lung cancer arising during pregnancy is rare and has been reported only 15 times since the 1950s. However, the use of chemotherapy for lung cancer during pregnancy has not previously been reported. METHODS: The history, treatment and outcome of a patient with stage IV non-small-cell lung carcinoma (NSCLC) diagnosed during pregnancy is presented. Previous published reports on lung cancer were retrieved by a literature search of Medline and Cancerlit. RESULTS: A 31-year-old woman was diagnosed as having stage IV NSCLC with bilateral pulmonary involvement when 26 weeks pregnant. Her shortness of breath progressed to dyspnea at rest on 100% inspired oxygen. Therefore, she was treated with systemic chemotherapy using cisplatin and vinorelbine. Despite this treatment, her oxygenation declined further over the next 4 days and thus the baby was delivered via cesarean section after 27 weeks of gestation. Four cycles of vinorelbine and cisplatin have now been administered. Following this treatment, the patient has experienced a significant clinical improvement and no longer requires supplemental oxygen. No chemotherapy-related adverse effects have been noted in the baby. In the 15 previously reported patients with concurrent lung cancer and pregnancy, chemotherapy administration during pregnancy has not been described. CONCLUSIONS: Treatment of lung cancer with chemotherapy during pregnancy should be considered on an individual basis with regard to the stage of the cancer and the maturity of the fetus. To our knowledge, the case presented here is the first report of a woman receiving chemotherapy for lung cancer while pregnant.

Neutralization of interferon-gamma in neonatal SOCS1-/- mice prevents fatty degeneration of the liver but not subsequent fatal inflammatory disease.

Mice lacking the suppressor of cytokine signalling-1 (SOCS1) die within weeks of birth with extensive fatty degeneration of the liver, consistent with acute hepatic toxicity to interferon-gamma (IFN-gamma), and inflammation of multiple organs. We show here that treatment for 1 week from birth with neutralizing antibody to IFN-gamma rescues SOCS1-/- mice from lethal liver disease but the mice subsequently succumb to chronic inflammatory lesions characterized by T-lymphocyte infiltration of skeletal muscle, pancreas, lung, liver and skin. Elevated blood levels of eosinophils, neutrophils and platelets were also observed and the thymic lymphocyte population was depleted of CD4+ CD8+ T cells and showed a reduced CD4 : CD8 ratio. All T-cell populations in thymus, spleen and lymph node exhibited an increased proportion of cells bearing the activation marker CD44. These data suggest an important role for SOCS1 in T-lymphocyte regulation.

Functional analysis of Asb-1 using genetic modification in mice.

The Asbs are a family of ankyrin repeat proteins that, along with four other protein families, contain a C-terminal SOCS box motif, which was first identified in the suppressor of cytokine signaling (SOCS) proteins. While it is clear that the SOCS proteins are involved in the negative regulation of cytokine signaling, the biological roles of the other SOCS box-containing families are unknown. We have investigated Asb-1 function by generating mice that lack this protein, as well as mice that overexpress full-length or truncated Asb-1 in a wide range of tissues. Although Asb-1 is expressed in multiple organs, including the hematopoietic compartment in wild-type mice, Asb-1(-/-) mice develop normally and exhibit no anomalies of mature blood cells or their progenitors. While most organs in these mice appear normal, the testes of Asb-1(-/-) mice display a diminution of spermatogenesis with less complete filling of seminiferous tubules. In contrast, the widespread overexpression of Asb-1 in the mouse has no apparent deleterious effects.

The multi-organ origin of interleukin-5 in the mouse.

Murine Ba/F3 cells were transfected with cDNA for the alpha-chain of the murine interleukin-5 (IL-5) receptor and cloned lines of these cells were able to proliferate in response to as little as 2.5 pg/ml of IL-5. The bioassay was demonstrated to be specific for IL-5 and was able to measure IL-5 produced in culture by organs from adult C57BL/6 and BALB/c mice. The highest levels of IL-5 were produced by lung tissue but thymus and bladder consistently produced IL-5 and more variable production was observed by the heart, spleen, muscle, bone shaft, uterus and testes. Bone marrow cells produced no detectable IL-5. Observed levels of production of IL-5 were similar when using organs from mice lacking high-affinity receptors for IL-5 and from nu/nu, RAG-1-/- and NOD/SCID mice lacking T lymphocytes. In inflammatory peritoneal exudates induced by the injection of casein plus bacteria, levels of induced IL-5 were higher if the mice lacked high-affinity receptors for IL-5. The data indicate that T lymphocytes are not the dominant cellular source of IL-5 in organ-conditioned media and that local IL-5 production can occur with a wide range of normal murine organs.

Placental defects and embryonic lethality in mice lacking suppressor of cytokine signaling 3.

Mice lacking suppressor of cytokine signaling 3 (SOCS3) exhibited embryonic lethality with death occurring between days 11 and 13 of gestation. At this stage, SOCS3(-/-) embryos were slightly smaller than wild type but appeared otherwise normal, and histological analysis failed to detect any anatomical abnormalities responsible for the lethal phenotype. Rather, in all SOCS3(-/-) embryos examined, defects were evident in placental development that would account for their developmental arrest and death. The placental spongiotrophoblast layer was significantly reduced and accompanied by increased numbers of giant trophoblast cells. Delayed branching of the chorioallantois was evident, and, although embryonic blood vessels were present in the labyrinthine layer of SOCS3(-/-) placentas, the network of embryonic vessels and maternal sinuses was poorly developed. Yolk sac erythropoiesis was normal, and, although the SOCS3(-/-) fetal liver was small at day 12.5 of gestation (E12.5), normal frequencies of erythroblasts and hematopoietic progenitor cells, including blast forming unit-erythroid (BFU-E) and, colony forming unit-erythroid (CFU-E) were present at both E11.5 and E12.5. Colony formation for both BFU-E and CFU-E from SOCS3(-/-) mice displayed wild-type quantitative responsiveness to erythropoietin (EPO), in the presence or absence of IL-3 or stem cell factor (SCF). These data suggest that SOCS3 is required for placental development but dispensable for normal hematopoiesis in the mouse embryo.