Genetic and phenotypic characteristics of Clostridium (Clostridioides) difficile from canine, bovine, and pediatric populations.

OBJECTIVES: Carriage of Clostridioides difficile by different species of animals has led to speculation that animals could represent a reservoir of this pathogen for human infections. The objective of this study was to compare C. difficile isolates from humans, dogs, and cattle from a restricted geographic area. METHODS: C. difficile isolates from 36 dogs and 15 dairy calves underwent whole genome sequencing, and phenotypic assays assessing growth and virulence were performed. Genomes of animal-derived isolates were compared to 29 genomes of isolates from a pediatric population as well as 44 reference genomes. RESULTS: Growth rates and relative cytotoxicity of isolates were significantly higher and lower, respectively, in bovine-derived isolates compared to pediatric- and canine-derived isolates. Analysis of core genes showed clustering by host species, though in a few cases, human strains co-clustered with canine or bovine strains, suggesting possible interspecies transmission. Geographic differences (e.g., farm, litter) were small compared to differences between species. In an analysis of accessory genes, the total number of genes in each genome varied between host species, with 6.7% of functional orthologs differentially present/absent between host species and bovine-derived strains having the lowest number of genes. Canine-derived isolates were most likely to be non-toxigenic and more likely to carry phages. A targeted study of episomes identified in local pediatric strains showed sharing of a methicillin-resistance plasmid with dogs, and historic sharing of a wide range of episomes across hosts. Bovine-derived isolates harbored the widest variety of antibiotic-resistance genes, followed by canine CONCLUSIONS: While C. difficile isolates mostly clustered by host species, occasional co-clustering of canine and pediatric-derived isolates suggests the possibility of interspecies transmission. The presence of a pool of resistance genes in animal-derived isolates with the potential to appear in humans given sufficient pressure from antibiotic use warrants concern.

A signaling pathway involving the diguanylate cyclase CelR and the response regulator DivK controls cellulose synthesis in Agrobacterium tumefaciens.

The production of cellulose fibrils is involved in the attachment of Agrobacterium tumefaciens to its plant host. Consistent with previous studies, we reported recently that a putative diguanylate cyclase, celR, is required for synthesis of this polymer in A. tumefaciens. In this study, the effects of celR and other components of the regulatory pathway of cellulose production were explored. Mutational analysis of celR demonstrated that the cyclase requires the catalytic GGEEF motif, as well as the conserved aspartate residue of a CheY-like receiver domain, for stimulating cellulose production. Moreover, a site-directed mutation within the PilZ domain of CelA, the catalytic subunit of the cellulose synthase complex, greatly reduced cellulose production. In addition, deletion of divK, the first gene of the divK-celR operon, also reduced cellulose production. This requirement for divK was alleviated by expression of a constitutively active form of CelR, suggesting that DivK acts upstream of CelR activation. Based on bacterial two-hybrid assays, CelR homodimerizes but does not interact with DivK. The mutation in divK additionally affected cell morphology, and this effect was complementable by a wild-type copy of the gene, but not by the constitutively active allele of celR. These results support the hypothesis that CelR is a bona fide c-di-GMP synthase and that the nucleotide signal produced by this enzyme activates CelA via the PilZ domain. Our studies also suggest that the DivK/CelR signaling pathway in Agrobacterium regulates cellulose production independent of cell cycle checkpoint systems that are controlled by divK.

CelR, an ortholog of the diguanylate cyclase PleD of Caulobacter, regulates cellulose synthesis in Agrobacterium tumefaciens.

Cellulose fibrils play a role in attachment of Agrobacterium tumefaciens to its plant host. While the genes for cellulose biosynthesis in the bacterium have been identified, little is known concerning the regulation of the process. The signal molecule cyclic di-GMP (c-di-GMP) has been linked to the regulation of exopolysaccharide biosynthesis in many bacterial species, including A. tumefaciens. In this study, we identified two putative diguanylate cyclase genes, celR (atu1297) and atu1060, that influence production of cellulose in A. tumefaciens. Overexpression of either gene resulted in increased cellulose production, while deletion of celR, but not atu1060, resulted in decreased cellulose biosynthesis. celR overexpression also affected other phenotypes, including biofilm formation, formation of a polar adhesion structure, plant surface attachment, and virulence, suggesting that the gene plays a role in regulating these processes. Analysis of celR and Δcel mutants allowed differentiation between phenotypes associated with cellulose production, such as biofilm formation, and phenotypes probably resulting from c-di-GMP signaling, which include polar adhesion, attachment to plant tissue, and virulence. Phylogenetic comparisons suggest that species containing both celR and celA, which encodes the catalytic subunit of cellulose synthase, adapted the CelR protein to regulate cellulose production while those that lack celA use CelR, called PleD, to regulate specific processes associated with polar localization and cell division.

Image based feasibility of renal sparing surgery for very low risk unilateral Wilms tumors: a report from the Children's Oncology Group.

PURPOSE: Nephrectomy with lymph node sampling is the recommended treatment for children with unilateral Wilms tumor under the Children's Oncology Group protocols. Using radiological assessment, we determined the feasibility of performing partial nephrectomy in a select group of patients with very low risk unilateral Wilms tumor. MATERIALS AND METHODS: We reviewed imaging studies of 60 patients with a mean age of less than 2 years with very low risk unilateral Wilms tumor (mean weight less than 550 gm) to assess the feasibility of partial nephrectomy. We evaluated percentage of salvageable parenchyma, tumor location and anatomical features preventing a nephron sparing approach. RESULTS: A linear relationship exists between tumor weight and computerized tomography estimated tumor volume. Mean tumor weight in the study population was 315 gm. Partial nephrectomy was deemed feasible in only 5 of 60 patients (8%). CONCLUSIONS: When considering a select population with very low risk unilateral Wilms tumor (lower volume tumor), only a small percentage of nonpretreated patients are candidates for nephron sparing surgery.

Non-operative treatment versus percutaneous drainage of pancreatic pseudocysts in children.

PURPOSE: The objective of this study was to characterize the clinical course and outcomes of children with pancreatic pseudocysts that were initially treated non-operatively or with percutaneous drainage. METHODS: A retrospective review of children with pancreatic pseudocysts over a 12-year period was completed. Categorical variables were compared using Fischer's exact method and the Student's t test was used to compare continuous variables. Analysis was done using logistic and linear regression models. RESULTS: Thirty-six children met the criteria for pancreatic pseudocyst and 33 children were treated either non-operatively or with percutaneous drainage. Of the 22 children managed non-operatively, 17 required no additional intervention (77 %) and five required surgery. Operative procedures were: Frey procedure (3), distal pancreatectomy (1), and cystgastrostomy (1). Eight of the 11 children treated with initial percutaneous drainage required no additional treatment (72 %). The other three children underwent distal pancreatectomy. Success of non-operative management or percutaneous drainage was not dependent on size or complexity of the pseudocyst Logistic regression did not identify any patient demographic (gender, age, and weight), etiologic (trauma, non-traumatic pancreatitis) or pseudocyst characteristic (size, septations) that predicted failure of non-operative therapy. CONCLUSIONS: In children, pancreatic pseudocysts can frequently be managed without surgery regardless of size or complexity of the pseudocyst. When an intervention is needed, percutaneous drainage can be performed successfully, avoiding the need for major surgical intervention in the majority of patients.

Laparoscopic appendectomy for perforated appendicitis: a comparison with open appendectomy.

BACKGROUND: The role of laparoscopic appendectomy for perforated appendicitis remains controversial. This study aimed to compare laparoscopic and open appendectomy outcomes for children with perforated appendicitis. METHODS: Over a 36-month period, 111 children with perforated appendicitis were analyzed in a retrospective review. These children were treated with either laparoscopic (n = 59) or open appendectomy. The primary outcome measures were operative time, length of hospital stay, time to adequate oral intake, wound infection, intraabdominal abscess formation, and bowel obstruction. RESULTS: The demographic data, presenting symptoms, preoperative laboratory values, and operative times (laparoscopic group, 61 +/- 3 min; open group, 57 +/- 3 were similar for the two groups (p = 0.3). The time to adequate oral intake was 104 +/- 7 h for the laparoscopic group and 127 +/- 12 h for the open group (p = 0.08). The hospitalization time was 189 +/- 14 h for the laparoscopic group, as compared with 210 +/- 15 h for the open group (p = 0.3). The wound infection rate was 6.8% for the laparoscopic group and 23% for the open group (p < 0.05). The wounds of another 29% of the patients were left open at the time of surgery. The postoperative intraabdominal abscess formation rate was 13.6% for the laparoscopic group and 15.4% for the open group. One patient in each group experienced bowel obstruction. CONCLUSIONS: Laparoscopic appendectomy for the children with perforated appendicitis in this study was associated with a significant decrease in the rate of wound infection. Furthermore, on the average, the children who underwent laparoscopic appendectomy tolerated enteral feedings and were discharged from the hospital approximately 24 h earlier than those who had open appendectomy.

From the Lab to the Farm: An Industrial Perspective of Plant Beneficial Microorganisms.

Any successful strategy aimed at enhancing crop productivity with microbial products ultimately relies on the ability to scale at regional to global levels. Microorganisms that show promise in the lab may lack key characteristics for widespread adoption in sustainable and productive agricultural systems. This paper provides an overview of critical considerations involved with taking a strain from discovery to the farmer's field. In addition, we review some of the most effective microbial products on the market today, explore the reasons for their success and outline some of the major challenges involved in industrial production and commercialization of beneficial strains for widespread agricultural application. General processes associated with commercializing viable microbial products are discussed in two broad categories, biofertility inoculants and biocontrol products. Specifically, we address what farmers desire in potential microbial products, how mode of action informs decisions on product applications, the influence of variation in laboratory and field study data, challenges with scaling for mass production, and the importance of consistent efficacy, product stability and quality. In order to make a significant impact on global sustainable agriculture, the implementation of plant beneficial microorganisms will require a more seamless transition between laboratory and farm application. Early attention to the challenges presented here will improve the likelihood of developing effective microbial products to improve crop yields, decrease disease severity, and help to feed an increasingly hungry planet.

Chromosomal location of genes controlling flavonoid production in hexaploid wheat.

Two-dimensional paper chromatography was performed on methanol extracts of leaves of hexaploid bread wheat, Triticum aestivum L. em. Thell. cultivar Chinese Spring, and of the available nullisomic-tetrasomic compensating lines, the tetrasomic lines and the ditelocentric lines. The chromatograms had 27 spots identified as flavonoids and six representing phenolic acids. Some of the areas were complex and contained more than one compound. Four flavonoids were identified as under the control of gene(s) on chromosome arms 1DS, 4DL, 5AS and 6BS. A phenolic glycoside was concluded to be controlled by a gene(s) on chromosome arm 7BL. Gene(s) on chromosome arm 4DL affected the amount of compounds in two other spots, and gene(s) on chromosome arm 4BS reduced the level of all flavonoid compounds. The individual compounds in some of the complex spots may be under the control of gene(s) on homoeologous chromosomes.

Follow-up of adolescents treated in a psychiatric hospital. Predictors of outcome.

In the context of a long-term follow-up of 60 hospitalized adolescent psychiatric patients (26 months to four years after discharge), we examined correlates of outcome. The variables were as follows: (1) severity of psychopathology; (2) onset of symptomatology (process or reactive); (3) type of hospital treatment termination; (4) continuation of individual psychotherapy following discharge; (5) physically destructive behavior before hospitalization; and (6) energy level. Follow-up was by personal clinical interview exploring the expatient's current living conditions, peer relationships, current psychopathology and drug or alcohol use, legal difficulties, academic and work functioning, subjective contentment, and plans for the future. An evaluation was also obtained from parents and/or spouse. Statistical analyses of the interrelationships among the predictor variables and outcome demonstrated the importance of a multivariate approach.

An evaluation of the mixed lymphocyte culture reaction in marmosets.

Marmosets are unique in that all members may be considered to be natural blood chimeras because of the high frequency of fraternal twinning and placental vascular anastomoses between the fetuses. The mixed lymphocyte culture (MLC) reaction utilizing blood lymphocytes was evaluated to determine whether this in vitro test could detect histocompatibility differences among related and unrelated marmosets. It was found that the responses could be correlated with the probable immunogenetic relationships of these animals. Thus, an allogeneic MLC reaction in which the responding (R) and stimulating (S) cells were obtained from unrelated animals within one subspecies of marmosets (Saquinus fuscicollis illigeri) yielded a lower response than a semi-xenogeneic reaction involving R and S cells from two different subspecies of marmosets (S.f. illigeri (R) versus S.f. lagonotus (S). In contrast, MLC reactions between cells from chimeric marmoset co-twins were essentially negative, indicating specific immune tolerance. Under certain experimental conditions, however, it was suggested that the dual lymphocyte cell population from a chimeric marmoset could undergo "autostimulation" as measured by label incorporation studies. The necessity of further experiments was recognized before the data could be truly accepted as reflecting an in vitro manifestation of incompatibility between the two different genetic populations of blood lymphocytes from a chimera.

Diagnostic utility of lower extremity radiographs of young children with gait disturbance.

The diagnostic utility of lower extremity radiographs was evaluated using 84 outpatients 1 to 5 years of age with gait disturbance whose lower extremities appeared physically normal. Chief complaints included limp (65 children [77%]), refusal to walk or stand (37 children [44%]), and frequent falling (6 children [7%]). A total of 43 children (51%) had more than one complaint. The mean age of patients was 26 months and the median duration of symptoms was 1 day. Trauma was reported in 43 (51%) cases and fever in 14 (17%). Results of radiographical studies appeared normal in 81 children (96%), demonstrated soft tissue swelling in 2 children, and revealed a bony island in 1 child. In 1 patient admitted to the hospital for failure to thrive and irritability, and whose radiographic results appeared normal, findings consistent with osteomyelitis later developed. Of the remaining children, 68 (81%) were available for follow-up observation 4 to 28 months after the initial visit and all reported spontaneous resolution of the initial complaint. It was concluded that in a well-appearing child with an otherwise normal physical examination results, an acute gait disturbance is likely to be a self-limiting condition and radiographs are unlikely to contribute to the diagnosis.

PACAP-38 causes phospholipase C-dependent calcium signaling in rat acinar cell line.

BACKGROUND: Pituitary adenylate cyclase activating peptide (PACAP-38), a neuropeptide of the vasoactive intestinal peptide/secretin family, localizes to intrapancreatic neurons and stimulates exocrine secretion from the pancreas. PACAP-38 stimulates calcium signaling in the rat pancreatic cell line AR42J. The purpose of this study was to elucidate the mechanisms of PACAP-evoked calcium signaling in these cells. METHODS: Continuous measurements of intracellular calcium were taken by fluorescent digital microscopy with the dye fura-2. Mechanisms of PACAP-38-evoked calcium signals were determined by a panel of inhibitors. Inositol phosphates production in response to PACAP-38 was measured. The ability of PACAP-38 to stimulate amylase release was used to determine a relevant dose range for these studies. RESULTS: We have shown that (1) AR42J cells respond to PACAP-38 with biphasic increases in [Ca2+]i in a dose-dependent fashion; (2) PACAP-38 acts through phospholipase C to release inositol triphosphate (IP3)-sensitive Ca2+ stores with (3) a subsequent influx of extracellular Ca2+. CONCLUSIONS: PACAP-38 activates calcium signaling through phospholipase C at concentrations that stimulate amylase release in AR42J cells.

Tachykinin neuropeptide-evoked intracellular calcium transients in cultured guinea pig myenteric neurons.

Substance P and related tachykinins are present in the mammalian gut and act as neurotransmitters. Microfluorimetric measurement of intracellular calcium ([Ca2+]i) was used to study tachykinin-sensitive myenteric neurons. Substance P (0.001-10 microM) evoked concentration-dependent increases in percentage of neurons responding (6-75%) and delta [Ca2+]i (88 +/- 24 to 212 +/- 16 nM). Neurokinin A (0.001-1 microM) produced similar responses. Removal of extracellular Ca2+ abolished substance P-induced Ca2+ signals, as did the addition of the Ca2+ channel blockers lanthanum chloride (5 mM) and nickel chloride (2.5 mM). Both nifedipine (1-50 microM) and diltiazem (1-50 microM) inhibited substance P-evoked Ca2+ responses in a dose-dependent manner. Substance P and related tachykinins evoke Ca2+ signaling in cultured myenteric neurons by the influx of extracellular Ca2+ through L and N-type plasma membrane Ca2+ channels.

Calcium signaling induced by angiotensin II in the pancreatic acinar cell line AR42J.

The purpose of this study was to characterize the nature and mechanisms of angiotensin II-evoked calcium signaling in AR42J cells. Cytosolic calcium concentrations were determined using fura-2-based microfluorimetry. Angiotensin II causes elevations in free cytosolic calcium ([Ca2+]i) in the rat pancreatic acinar cell line AR42J. The mechanisms of angiotensin II-evoked calcium signaling were examined using fura-2-based fluorescent digital microscopy. Angiotensin II caused dose-dependent increments in [Ca2+]i over a concentration range of 0.1-1,000 nM, with an average increment of 243 +/- 16 nM at an angiotensin II concentration of 1,000 nM. Dup753, an AT1-specific antagonist, inhibited angiotensin II-evoked signaling, whereas the AT2 antagonist PD123,319 had no effect. Preincubation with the phospholipase C inhibitor U73122 reduced the response in [Ca2+]i to 25% of that of the control. Thapsigargin abolished angiotensin II-evoked calcium signaling. The inositol 1,4,5-trisphosphate receptor antagonist heparin introduced by radiofrequency electroporation inhibited responses to 46 +/- 6% of controls. Angiotensin II-evoked signals were reduced in magnitude and duration by elimination of Ca2+ from the extracellular buffer. Preincubation with pertussis toxin (100 ng/ml) had no effect. Angiotensin II did not stimulate cyclic AMP or suppress vasoactive intestinal peptide stimulated cyclic AMP production over the concentration range that caused Ca2+ signaling.

Cholinergic intrapancreatic neurons induce Ca²+ signaling and early-response gene expression in pancreatic acinar cells.

Pancreatic exocrine function has been demonstrated to be under neuronal regulation. The pathways responsible for this effect, and the long-term consequences of such interactions, are incompletely described. The effects of neuronal depolarization on pancreatic acinar cells were studied to determine whether calcium signaling and c-fos expression were activated. In pancreatic lobules, which contain both neurons and acinar cells, agonists that selectively stimulated neurons increased intracellular calcium in acinar cells. Depolarization also led to the expression of c-fos protein in 24% +/- 4% of the acinar cells. In AR42J pancreatic acinar cells, cholinergic stimulation demonstrated an average increase of 398 +/- 19 nmol/L in intracellular calcium levels, and induced c-fos expression that was time and dose dependent. The data indicate that intrapancreatic neurons induce Ca²+ signaling and early-response gene expression in pancreatic acinar cells.

Scripps Clinic: in transition to the on-line medical record.

The TMI system was implemented at our main campus on March 4, 1991, and at this point we are very pleased with all aspects of system performance. Since the conversion, the number of jobs dictated by our physicians has increased 20%, and we interpret this increase as an objective measure of physician satisfaction with the system. An increasing number of physicians are accessing lab results and documents from home via modem to review the next day's patients or while on-call. Transcription productivity has improved and enthusiasm for the system is high. Requests for chart documentation from our business office have decreased 60% due to the ability to access and print documents directly from the mainframe. The next phase in our information plan involves the installation of the TMI system at our regional clinics and our inpatient transcription unit. Further steps in the transition to on-line medical records, such as the conversion of 600,000 active and archived records, awaits the further development of technology in order to be feasible and cost effective. Our experience has shown that developing complex applications such as the TMI demands perseverance and a willingness to work closely with multiple vendors and products in order to identify the best options in a rapidly developing field. Extensive involvement of end users early in the planning process helped us to secure and implement a system with a high level of user acceptance and satisfaction.

Immediate and long-term results of surgical management of low imperforate anus in girls.

BACKGROUND: The majority of girls with imperforate anus are reported to have a malformation of the low variety. Despite this, much of the literature has focused on the more complex, high lesions. METHODS: This study reviews our experience with 44 girls with low imperforate anus from a 22-year period. RESULTS: The incidence of associated anomalies was 61%, which is higher than generally reported. All patients in the study had anal fistulae. Fifty-seven percent had perineal fistulae, 23% had fourchette fistulae, and 20% had vestibular fistulae. Cutback anoplasty was performed in 55%, Potts transfer anoplasty was used in 27%, and 18% of patients were treated with either limited posterior sagittal anorectoplasty or anterior sagittal anorectoplasty. Surgical complications were uncommon. Long-term follow-up was carried out by telephone survey. This showed 89% of the girls to be successfully toilet trained. However, 47% of patients experience at least occasional soilage or episodic fecal incontinence. CONCLUSIONS: Low imperforate anus can be successfully treated using a variety of procedures without colostomy. Most girls with low imperforate anus are successfully toilet trained, but problems with continence persist in a significant number of these patients.

Conservative management of mesenchymal hamartoma of the liver.

The natural history of mesenchymal hamartoma of the liver is poorly understood. This case demonstrates the course of a biopsy-proven mesenchymal hamartoma using sequential computed tomography (CT) examinations. These CT scans show initial expansion of the lesion with subsequent involution. The spontaneous resolution in this patient suggests the possibility of conservative management of asymptomatic mesenchymal hamartomas. The case is presented, and the literature on mesenchymal hamartoma is reviewed.

Dose-responsive characteristics of meperidine sedation in preschool children.

Using double-blind conditions, 60 uncooperative and fearful preschool children (24-66 months) received intramuscular injections of meperidine 0.25, 0.50, 1.00 mg/lb or placebo prior to restorative dental treatment. Behavior was assessed by the dentist and an independent observer during five specific treatment procedures. Behavioral ratings found meperidine to be an effective sedative, with 0.50 mg/lb and 1.00 mg/lb being significantly more effective than placebo (P less than 0.05, Kruskal-Wallis). Children receiving 1.0 mg/lb of meperidine had significantly more nausea and vomiting than patients receiving lower doses of the drug (P less than 0.05, Chisquare). Physiologic monitoring demonstrated that the highest dose of meperidine was associated with transient drops in arterial oxygen saturation. Meperidine sedation was found to be more effective for older children (37-66 months) and for children initially rated as being only moderately uncooperative and fearful.