BOP reagent for the coupling of pGlu and Boc-His(Tos) in solid phase peptide synthesis

The model peptide TRH was successfully synthesized using benzotriazol-l-yl-oxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP reagent). The coupling reactions were carried out in N,N-dimethylformamide or N-methylpyrrolidone. These solvents allowed the incorporation of the N-terminal pyroglutamic acid residue into the peptide chain, without using the derivative bearing the N-benzyloxycarbonyl group, which acts as a solubility promoter. A comparative racemization study showed that Boc-His(Tos) can be coupled by means of BOP reagent with less racemization than with DCC when the amount of diisopropylethylamine (DIEA) is kept minimal (same ratio of equivalents as for Boc-His(Tos), i.e. 3 equiv.). However, with the use of a larger amount of DIEA in the coupling mixture (9 equiv.), approximately 3% of epimer was found in the crude product. Our study showed that even under low DIEA conditions, the rate of coupling of the residues with BOP remained comparable to that observed with DCC.     

The relation of impaired vitamin A and E tolerance to fat absorption in biliary diversion.

Eleven patients have been studied after cholecystectomy with exploration of the common bile duct (CBD) and insertion of a T tube for free biliary drainage. Prior to clamping the T tube no significant rise was seen above fasting serum vitamin A and E, or serum triglyceride levels after 6 of the patients had been given these substances in a liquid test meal. In addition no rise in fasting vitamin E levels was seen after 3 subjects had been loaded for 4 days with 0.5 g DL alpha-tocopherol acetate/day. Faecal fat collections performed on 9 subjects indicated that over 70% of the ingested fat was absorbed. All these findings returned to normal when the T tube was clamped and the intraluminal flow of bile re-established. We conclude that deficiency of bile may allow the absorption of fat in the absence of fat soluble vitamins.     

Cysticercosis presenting as a mass lesion at foramen of Monro.

Cysticercosis is a parasitic infestation that commonly affects the central nervous system. This is a report of computed tomography findings in a patient with a noncalcified cyst causing asymmetric lateral ventricular obstruction at the foramen of Monro. The lesion was isodense and uniformly enhancing, an unusual finding possibly related to presentation early in the course of the disease. This disease should be considered in the differential diagnosis of the lesions at the foramen of Monro in patients with appropriate residence or travel history.     

Radiographic features of granulocytic sarcoma (chloroma).

The computed tomographic (CT) findings in two patients in whom intracranial granulocytic sarcomas preceded the onset of systemic myelogenous leukemia are presented. On CT, granulocytic sarcomas may be indistinguishable from meningiomas and difficult to differentiate from primary central nervous system malignant lymphoma and eosinophilic granuloma.     

MR of toxic effects of accelerated fractionation radiation therapy and carboplatin chemotherapy for malignant gliomas.

PURPOSETo present MR findings of parenchymal brain injury after accelerated fractionation radiation therapy combined with carboplatin chemotherapy in the treatment of malignant brain gliomas.METHODSEighty-one evaluable subjects in an ongoing treatment protocol for malignant gliomas form the patient base for this report. After surgical resection of tumors, patients underwent a course of accelerated fractionation radiation therapy to a total dose of 60 Gy. Carboplatin was infused intravenously before each radiation treatment. Precontrast and postcontrast MR scans were obtained before treatment and at 4-week intervals afterward and were analyzed retrospectively.RESULTSPosttreatment MR imaging in 20 of the 81 patients showed development of unusual parenchymal lesions or enlarging masses needing debulking, and these patients underwent second operations. Two groups emerged: those with tumor and necrotic brain (n = 11) and those with necrosis and reactive gliosis but no definitive tumor (n = 9). Enhancing lesions in the tumor-negative group appeared later than those in the tumor-positive group, were often multiple, and were usually located several centimeters away from the tumor resection site or even contralaterally. Common locations were the corpus callosum and corticomedullary junctions. Lesions in the tumor-positive group were more often solitary and located immediately adjacent to the surgical site. Positive and negative results of positron emission tomography with fludeoxyglucose F 18 were obtained in both groups. The incidence of brain necrosis without associated tumor was 11%.CONCLUSIONSA pattern of unusual enhancing parenchymal brain lesions was seen on MR imaging after accelerated fractionation radiation therapy and concomitant carboplatin chemotherapy. The abnormalities seem more extensive than focal necrotic lesions on enhanced CT or MR imaging after conventional radiation therapy, and they may mimic recurrent tumor.     

Factors that help injecting drug users to access and benefit from services: A qualitative study

Background  

International research shows that injecting drug users (IDUs) can encounter many barriers when they try to access drug treatment and other services. However, the existing literature is mostly quantitative and does not consider the kinds of factors that injectors themselves identify as enabling them to access and benefit from services. Responding to this gap in knowledge, our paper explores IDUs' own suggestions for improving service engagement and their reports of other factors enabling them to seek help.     

Quantitative morphology of the corpus callosum in children with neurofibromatosis and attention-deficit hyperactivity disorder

Neurofibromatosis-1 is a common autosomal-dominant genetic disorder associated with numerous physical anomalies and an increased incidence of attention-deficit hyperactivity disorder (ADHD). Studies of children with idiopathic ADHD have suggested a link between corpus callosum size and symptom severity. This study examines the contribution of corpus callosum morphology to symptoms of ADHD in children with neurofibromatosis. Eighteen control subjects and 36 children with neurofibromatosis underwent magnetic resonance imaging of the brain. Twelve subjects with neurofibromatosis had evidence of ADHD and 24 did not. Subjects with neurofibromatosis had significantly larger total corpus callosum area and significantly larger regional measurements in three of seven areas. However, there were no differences between the neurofibromatosis alone and neurofibromatosis plus ADHD groups. Increased severity of attention problems was associated with smaller total callosal areas. These results suggest that some features of ADHD in children with neurofibromatosis could be linked to quantifiable differences in brain morphology, but the nature of the genetic mutation in neurofibromatosis suggests that neurochemical effects also could be important.