Neuropathology of ablation of rat gliosarcomas and contiguous brain tissues using a microplanar beam of synchrotron-wiggler-generated X rays

Adult-rat-brain tissues display an unusually high resistance to necrosis when serially irradiated with parallel, thin slices of a microplanar (i.e., microscopically thin and macroscopically broad) beam of synchrotron-wiggler-generated, approx. 35–120 keV (median approx. 50 keV) Gd-filtered X rays at skin-entrance absorbed doses of 312 to 5000 Gy per slice. Such microplanar beams were used to irradiate young adult rats bearing right frontocerebral 9L gliosarcomas (approx. 4 mm diameter), through a volume of tissue containing the tumor and contiguous brain tissue, either in a single array or in 2 orthogonally crossed arrays of tissue slices. Each array included 101 parallel microplanar slices, 100 μm center-to-center distance, each slice being approx. 25 μm wide and 12 mm high, with skin-entrance absorbed doses of 312.5 Gy or 625 Gy per slice. Compared with unirradiated controls with a median survival time of 20 days after tumor initiation, the median survival time was extended in irradiated rats by 139 days (625 Gy, crossed arrays), 96 days (312.Gy, crossed arrays) or 24 days (625 Gy, single array). The tumors disappeared in 22 of the 36 irradiated rats, 4/ 11 even after unidirectional microbeam irradiation. The extent and severity of radiation damage to the normal brain in rats with or without tumor was graded histopathologically. Correlation of those grades with radiation doses shows that loss of tissue structure was confined to beam-crossing regions and that only minor damage was done to zones of the brain irradiated unidirectionally. Int. J. Cancer 78:654–660, 1998. © 1998 Wiley-Liss, Inc.     

Use of Laboratory Tests to Guide Initiation of Autologous Hematopoietic Progenitor Cell Collection by Apheresis: Results From the Multicenter Hematopoietic Progenitor Cell Collection by Apheresis Laboratory Trigger Survey

Limited literature describes the value of laboratory “triggers” to guide collection of peripheral blood (PB) hematopoietic progenitor cells (HPCs) by apheresis [HPC(A)]. We used a web-based survey to determine which parameters are used to initiate autologous HPC(A) collection in adult and pediatric patients and to identify common practice patterns. Members of the AABB Cellular Therapy Product Collection and Clinical Practices Subsection and the American Society for Apheresis HPC Donor Subcommittee drafted and developed relevant survey questions. A web link to the survey was distributed by electronic newsletter or email. Responses from 67 programs that perform autologous HPC(A) collections, including academic medical centers (n = 46), blood centers (n = 10), community hospitals (n = 5), and a variety of other medical institutions (n = 6), were analyzed. Ninety-three percent (62/67) of programs used a laboratory parameter to initiate HPC(A) collection. In both adult (40/54, 74%) and pediatric (29/38, 76%) patients, the PB CD34 + cell count was the most common parameter used to initiate HPC(A) collection. The median PB CD34 + trigger value was 10/μL for both patient populations. Among centers routinely using the PB CD34 + cell count to initiate apheresis, 51% (22/43) first sent the test before the patient presented for collection. Although more than 90% of centers used a laboratory test to trigger apheresis in cytokine-mobilized (44/48) or chemomobilized patients (50/53), only 57% (30/53) used a laboratory trigger if the patient was mobilized with granulocyte colony-stimulating factor plus plerixafor. Forty-two percent (21/50) of programs that routinely measured the PB CD34 + count before collection and discontinued further HPC(A) collection based on product CD34 + cell yield also stopped if the PB CD34 + value before apheresis was considered too low to proceed. Most programs use the PB CD34 + cell count to trigger autologous HPC(A) collection. Some centers also use this parameter to stop further collections. Laboratory tests are used less frequently to initiate apheresis when patients are mobilized with plerixafor. These data reveal ongoing diversity in clinical practices and suggest that consensus guidelines on use of laboratory parameters may further optimize HPC(A) collection.     

KRAS-mutation status in relation to colorectal cancer survival: the joint impact of correlated tumour markers

Background:

Mutations in the Kirsten Ras (KRAS) oncogene are common in colorectal cancer (CRC). The role of KRAS-mutation status as a prognostic factor, however, is unclear. We evaluated the relationship between KRAS-mutation status and CRC survival, considering heterogeneity in this association by tumour and patient characteristics.

Methods:

The population-based study included individuals diagnosed with CRC between 1998–2007 in Western Washington State. Tumour specimens were tested for KRAS exon 2 mutations, the BRAF p.V600E mutation, and microsatellite instability (MSI). We used Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between KRAS-mutation status and disease-specific and overall survival. Stratified analyses were conducted by age, sex, tumour site, stage, and MSI. We conducted additional analyses combining KRAS-mutation, BRAF-mutation, and MSI status.

Results:

Among 1989 cases, 31% had KRAS-mutated CRC. Kirsten Ras (KRAS)-mutated CRC was associated with poorer disease-specific survival (HR=1.37, 95% CI: 1.13–1.66). This association was not evident in cases who presented with distant-stage CRC. Cases with KRAS-wild-type/BRAF-wild-type/MSI-high CRC had the most favourable prognosis; those with CRC exhibiting a KRAS- or BRAF-mutation and no MSI had the poorest prognosis. Patterns were similar for overall survival.

Conclusion:

Kirsten Ras (KRAS)-mutated CRC was associated with statistically significantly poorer survival after diagnosis than KRAS-wild-type CRC.     

Formate metabolism in young swine

Formate generated from methanol metabolism in vivo is the chemical entity responsible for the development of the methanol toxicity syndrome in the monkey. Compared to rats, monkeys are in a state of folate deficiency. This leads to a decreased ability to dispose of formate generated leading to its accumulation and the subsequent development of the classic symptoms of methanol toxicity. Rats possess a more efficient folate system; therefore, they metabolize formate very readily and do not exhibit methanol toxicity symptoms. In this report, the hepatic folate content and the ability to handle a formate "load" were evaluated in another animal species, the pig. The results obtained indicate that the pig, compared to all other species studied, has extremely low levels of folates and very low levels of a key enzyme in the folate pathway, namely 10-formyl H4folate dehydrogenase. Also the pig's ability to dispose of formate was extremely limited and slower than that observed in rats or monkeys. These results suggest that the pig may be a suitable animal model for studying formate metabolism and possibly methanol toxicity.     

Potential contribution of cytochrome P450 2B6 to hepatic 4-hydroxycyclophosphamide formation in vitro and in vivo

Results from retrospective studies on the relationship between cytochrome P450 (P450) 2B6 (CYP2B6) genotype and cyclophosphamide (CY) efficacy and toxicity in adult cancer patients have been conflicting. We evaluated this relationship in children, who have faster CY clearance and receive different CY-based regimens than adults. These factors may influence the P450s metabolizing CY to 4-hydroxycyclophosphamide (4HCY), the principal precursor to CY's cytotoxic metabolite. Therefore, we sought to characterize the in vitro and in vivo roles of hepatic CYP2B6 and its main allelic variants in 4HCY formation. CYP2B6 is the major isozyme responsible for 4HCY formation in recombinant P450 Supersomes. In human liver microsomes (HLM), 4HCY formation correlated with known phenotypic markers of CYP2B6 activity, specifically formation of (S)-2-ethyl-1,5-dimethyl-3,3-diphenyl pyrrolidine and hydroxybupropion. However, in HLM, CYP3A4/5 also contributes to 4HCY formation at the CY concentrations similar to plasma concentrations achieved in children (0.1 mM). 4HCY formation was not associated with CYP2B6 genotype at low (0.1 mM) or high (1 mM) CY concentrations potentially because CYP3A4/5 and other isozymes also form 4HCY. To remove this confounder, 4HCY formation was evaluated in recombinant CYP2B6 enzymes, which demonstrated that 4HCY formation was lower for CYP2B6.4 and CYP2B6.5 compared with CYP2B6.1. In vivo, CYP2B6 genotype was not directly related to CY clearance or ratio of 4HCY/CY areas under the curve in 51 children receiving CY-based regimens. Concomitant chemotherapy agents did not influence 4HCY formation in vitro. We conclude that CYP2B6 genotype is not consistently related to 4HCY formation in vitro or in vivo.     

Nature and onset of communication disorder in pediatrics with HIV

American Speech-Language Association (ASHA) and the International Association of Physicians in AIDS Care (IAPAC) reported that speech-language and hearing disorders that occur as a direct or indirect consequence of HIV-infection are so common. However there has been little research into the nature and onset of such communication disorders in children living with HIV. Therefore the purpose of the study is to understand about the nature and onset of audiological and speech-language disorders of a group of children with HIV for the better management. In methodology 67 children (4-16 years, mean: 11.06) with HIV infection took part in the study. Otoscopic examination, Pure-tone and Impedance audiometry, REELS, SECS, PAT, FDA and BUFFALO-III was used to assess. In result, 22/67 individuals had hearing loss, 17/67 had swallowing disorder, 21/67 individuals had voice problems. Language development was delayed in 21/67 of the individuals at the pragmatic and syntactic level and 7/67 had the deviant language. There was negative correlation (r=-0.932) between the duration of HIV infection and degree of severity of communication disorders in the participants.     

A diagnostic algorithm in the postcholecystectomy syndrome

The diagnostic informative value (according to the "sensitivity" and "specificity" tests) of the findings of clinical, laboratory, biochemical (CI, LI, BI), and adjuvant methods of investigation in 74 patients with postcholecystectomy syndrome (PCES), who underwent reoperations, was established. The open to general use diagnostic algorithm of PCES was determined. CI, LI, BI are preliminary screening tests. The use of adjuvant methods, their sequence and combination depend on the character of the diagnostic information obtained.