Glutamate biosensor imaging reveals dysregulation of glutamatergic pathways in a model of developmental cortical malformation

Cortical malformations can cause intractable epilepsy, but the underlying epileptogenic mechanisms are poorly understood. We used high-speed glutamate biosensor imaging to ask how glutamatergic signaling is altered in cortical malformations induced by neonatal freeze-lesions (FL). In non-lesion neocortical slices from 2 to 8week old rats, evoked glutamate signals were symmetrical in the medio-lateral axis and monotonic, correlating with simple, brief (≈50ms) local field potentials (LFPs). By contrast, in FL cortex glutamate signals were prolonged, increased in amplitude, and polyphasic, which paralleled a prolongation of the LFP. Using glutamate biosensor imaging, we found that glutamate signals propagated throughout large areas of FL cortex and were asymmetric (skewed toward the lesion). Laminar analysis demonstrated a shift in the region of maximal glutamate release toward superficial layers in FL cortex. The ability to remove exogenous glutamate was increased within the FL itself but was decreased in immediately adjacent regions. There were corresponding alterations in astrocyte density, with an increase within the lesion and a decrease in deep cortical layers surrounding the lesion. These findings demonstrate both network connectivity and glutamate metabolism are altered in this cortical malformation model and suggests that the regional ability of astrocytes to remove released glutamate may be inversely related to local excitability.

An open-label, multicenter, phase II study of AT-101 in combination with rituximab (R) in patients with untreated, grade 1-2, follicular non-Hodgkin's lymphoma (FL)

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Background: Bcl-2 family proteins are overexpressed in the majority of patients with FL and contribute to resistance to therapy. AT-101 is a pan-Bcl-2 inhibitor (Bcl-2, Bcl-XL, Bcl-W, and Mcl-1) and potent inducer of proapoptotic proteins. It is active as a single agent and in combination with R in NHL tumor models. Methods: Patients with untreated FL who did not require immediate chemotherapy were eligible. Treatment consisted of an induction cycle of AT-101 (30mg po daily × 21) and R (375 mg/m2 weekly × 4) followed by up to 4 maintenance cycles of AT-101 (30mg po daily × 21) and R (375 mg/m2) every 8 weeks in nonprogressors. Endpoints evaluated the response rate (RR) at week 8 (primary), overall response rate (ORR), molecular response rate (BCL-2JH rearrangement in blood and bone marrow), and safety of the combination. A mini-Max, 2-stage design (52 pts planned) was used to detect >70% RR with power of 90% and alpha of 0.10. Results: 23 pts enrolled: median age 64 yrs; FLIPI 0–5: 0%/17%/65%/13%/4%; Grade 1/2: 61%/39%; bulky disease (>5cm3): 35%; stage: 1–4 4%/4%/30%/61%; bone marrow + 48%. All pts received induction and 18 pts received 1 or more maintenance cycles. RR following induction was 26% (95%CI=10.2–48.4), 4% CR and the best ORR was 70% (95%CI=47.1–86.8), 35% CR. Molecular response analysis is ongoing. Grade 3/4 AEs that occurred in ≥2 pts: nausea 4(17%), vomiting 2(9%), abdominal pain 2(9%), fatigue 2(9%), and small bowel obstruction 2(9%). AT-101 was reduced to 20mg daily x 21 which improved GI tolerability. Conclusions: The combination of AT-101 and R was well tolerated. The week 8 RR did not meet statistical criteria to enroll stage II. The best ORR is at the upper limit of reported ORR for R alone; therefore a randomized trial is required to definitively determine activity of the combination.

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Multiple genes for the last step of proline biosynthesis in Bacillus subtilis

The complete Bacillus subtilis genome contains four genes (proG, proH, proI, and comER) with the potential to encode Delta(1)-pyrroline-5-carboxylate reductase, a proline biosynthetic enzyme. Simultaneous defects in three of these genes (proG, proH, and proI) were required to confer proline auxotrophy, indicating that the products of these genes are mostly interchangeable with respect to the last step in proline biosynthesis.

Long-term results of pediatric liver transplantation: an analysis of 569 transplants

OBJECTIVE

To analyze a single center's 13-year experience with 569 pediatric orthotopic liver transplants for end-stage liver disease.

SUMMARY BACKGROUND DATA

Despite advances in medical therapy, liver replacement continues to be the only definitive mode of therapy for children with end-stage liver disease. Innovative surgical techniques and improved immunosuppression have broadened the application of liver replacement for affected children. However, liver transplantation in the child remains challenging because of the scarcity of donor organs, complex surgical technical demands, and the necessity to prevent long-term complications.

METHODS

The medical records of 440 consecutive patients younger than 18 years of age undergoing orthotopic liver transplantation for end-stage liver disease from March 20, 1984, to November 15, 1997, were reviewed. Results were analyzed using Cox multivariate regression analysis to determine the statistical strength of independent associations between pretransplant covariates and patient and graft survival. Actuarial patient and graft survival rates were determined at 1, 3, 5, and 10 years. The type and incidence of posttransplant complications were determined, as was the quality of long-term allograft function. The median follow-up period was 4.1 years.

RESULTS

Biliary atresia was the most common cause (50.4%) of endstage liver disease in this patient population. The median recipient age was 2.4 years; 239 patients (54%) were younger than 3 years of age and 1 11 patients (25%) were younger than 1 year of age. There were 471 whole organs, 29 were ex vivo reduced size, 33 were living-related donor, and 36 were in situ split-liver allografts. Three hundred forty-three (78%) patients underwent a single allograft, whereas 97 patients required retransplantation; hepatic artery thrombosis was the most common indication for retransplantation (55 patients). The 1-, 3-, 5-, and 10-year actuarial patient survival rates were 82%, 80%, 78%, and 76%, respectively; allograft survival rates were 68%, 63%, 60%, and 54%. Long-term liver function remains excellent: current median follow-up values for total bilirubin and aspartate aminotransferase were 0.5 mg/dl and 54 IU/L, respectively. Cox multivariate regression analysis demonstrated that pretransplant patient age, the era of transplantation, and the number of allografts performed significantly and independently predicted patient survival rates, whereas allograft type and pretransplant diagnosis did not.

CONCLUSIONS

Liver transplantation in the pediatric patient is a durable procedure that provides excellent long-term survival. Although there have been overall improvements in patient outcome with increased experience, the effect is most pronounced for patients younger than 1 year of age. Retransplantation, although effective in a meaningful number of patients, continues to carry a progressive decrement in survival with the number of allografts performed. Use of living-related and in situ split-liver allografts has dramatically reduced waiting times for small children and has improved patient survival.

Cantharidin production in a blister beetle

Cantharidin, a potent defensive chemical, is present in all ten life stages of the blister beetle Epicauta funebris. The first five larval stages accumulate cantharidin as they feed and grow in size. When disturbed, they exude cantharidin in a milky oral fluid, not in hemolymph which adult beetles reflexively discharge from leg joints. Two subsequent larval stages and the pupa do not feed, grow, regurgitate, or change in their defensive reserves (110 micrograms cantharidin/insect, regardless of sex). Adult beetles kept in isolation for 60-90 d exhibit a pronounced sexual dimorphism in cantharidin production: the male biosynthesizes about 17 mg of the toxin, representing 10% of his live weight, whereas the female actually loses most of her defensive reserves. But in the wild a female beetle repeatedly acquires cantharidin as copulatory gifts from her mates.

The microbiology of chronic sinus disease in children with respiratory allergy

Chronic maxillary sinusitis is common in children with respiratory allergy and is associated with increased morbidity. The bacteriology of chronic sinus disease in these children has not been adequately evaluated. Between May 1987 and January 1988, 12 children (aged 3 to 9 years), all with documented respiratory allergy and chronic respiratory symptoms consistent with chronic sinusitis (greater than 30 days), were fully evaluated. History, physical examination, complete blood count, nasal smear, and Waters x-ray were done. All patients had opacification of one or both maxillary sinuses, failed to respond to multiple courses of antibiotics, and subsequently underwent maxillary sinus aspiration and irrigation. Specimens were cultured for aerobic and anaerobic organisms with standard technique, and sensitivities were obtained. Culture results revealed a single organism (Moraxella [Branhamella] catarrhalis) in five patients, one patient yielded M. catarrhalis plus Streptococcus species, three were negative, and three patients grew multiple organisms (two with multiple aerobic streptococcal species and one patient with aerobic streptococci and Peptostreptococcus). All children received appropriate culture-directed antimicrobial therapy. Sequential biweekly follow-up revealed progressive radiographic clearing and significant symptomatic improvement. M. catarrhalis is a common pathogen, whereas anaerobic organisms are unusual as a cause of chronic maxillary sinusitis in allergic children. Some children, despite negative cultures, may benefit from maxillary sinus irrigation.

Comparison of survivors and nonsurvivors in pediatric intensive care

PURPOSE

To identify characteristics of survivors and nonsurvivors among critically ill children admitted to a pediatric intensive care unit.

METHOD

A retrospective chart review of 91 children (64 survivors and 27 nonsurvivors) compared age, gender, diagnostic category, and number of days in the ICU. Data were analyzed by Fisher's Exact Test and ANOVA.

RESULTS

There were no significant differences among groups.

CONCLUSIONS

Data contribute to the development and testing of predictive models for decision-making in pediatric intensive care.

Proportion of beta-D-glucuronidase-negative Escherichia coli in human fecal samples

Convenient assays and reports that almost all clinical isolates of Escherichia coli produce beta-D-glucuronidase (GUR) have led to great interest in the use of the enzyme for the rapid detection of the bacterium in water, food, and environmental samples. In these materials, E. coli serves as an indicator of possible fecal contamination. Therefore, it was crucial to examine the proportion of GUR-negative E. coli in human fecal samples. The bacterium was isolated from 35 samples, and a mean of 34% and a median of 15% were found to be GUR negative in lauryl sulfate tryptose broth with 4-methylumbelliferyl-beta-D-glucuronide. E. coli from three samples were temperature dependent for GUR production: very weakly positive at 37 degrees C but strongly positive at 44.5 degrees C. These results remind us of differences between fecal and clinical E. coli populations, of diversity in GUR regulation and expression in natural populations of E. coli, and of the need for caution in using GUR for the detection of fecal E. coli.

Bone disease in pediatric patients undergoing dialysis with CAPD or CCPD

The histologic features of renal osteodystrophy and the prevalence of bone aluminum deposition in children receiving regular dialysis have not been described. Forty-four pediatric patients undergoing continuous ambulatory (CAPD) or cycling (CCPD) peritoneal dialysis had bone biopsies and deferoxamine (DFO) infusion tests; all were receiving oral calcitriol. Osteitis fibrosa (OF) was found in 39%, mild lesions (M) in 25%, normal histology (NH) in 16%, aplastic lesions (AP) in 11%, and osteomalacia (OM) in 9%. Bone surface aluminum (SA) was present by histochemical staining in 10 out of 20 given aluminum-containing phosphate-binding agents and in 0 of 24 treated with calcium carbonate; chi 2 = 15.5, P less than 0.0001. Serum biochemistries and DFO infusion tests failed to predict bone histology, but plasma aluminum levels were markedly elevated and bone aluminum content was highest in patients with OM. Bone formation rate (BFR) correlated with serum parathyroid hormone (PTH), r = 0.55, P less than 0.001; BFR was inversely related to bone aluminum content (r = -0.42, P less than 0.01), even in patients with OF (r = -0.66, P less than 0.05). All patients with SA greater than 30% had normal or reduced BFR when compared to those with SA less than 30%; chi 2 = 12.2, P less than 0.005. Based on SA greater than 30%, six patients were classified as aluminum-related bone disease: three OM, one AP, and two NH. Two-thirds of pediatric patients undergoing CAPD/CCPD have persistent hyperparathyroidism despite treatment with calcitriol, but aluminum can adversely affect BFR when SA exceeds 30% regardless of histologic lesion or serum PTH level.

Astigmatism in infants

Compared with children of school age, infants show ten times the incidence and considerably greater amounts of clinically significant astigmatism. The amount begins to decrease in the second semester of life, and the incidence declines during the third year. The unanticipated results bear on both the etiology and the neural sequelae of astigmatism.