Forward or inversely planned segmental multileaf collimator IMRT and sequential tomotherapy to treat multiple dominant intraprostatic lesions of prostate cancer to 90 Gy

PURPOSE: To investigate the technical feasibility of using forward or inversely planned segmental multileaf collimator (SMLC) intensity-modulated radiotherapy and sequential tomotherapy (ST) to escalate to a dose of 90 Gy to multiple dominant intraprostatic lesions within the prostate gland while delivering a dose of 75.6 Gy to the remaining prostate. METHODS AND MATERIALS: A selected case with one dominant intraprostatic lesion located at the left base and a second dominant intraprostatic lesion at the right apex of the prostate was planned using three different intensity modulation techniques. Two plans were generated with inverse treatment planning, using either SMLC or ST with a special multivane collimator. The third plan also employed SMLC but was generated using forward planning. All three plans were compared based on dose-volume histograms, isodose distributions, and doses to sensitive normal structures. RESULTS: All three plans meet and exceed the desired dose constraints, limiting doses to the rectum and bladder to an estimated RTOG Grade 2 complication rate of <10%. The ST plan achieved the best dose conformality, whereas the inverse SMLC plan gave the lowest dose to the rectal wall, and the forward SMLC plan obtained the best dose homogeneity inside the targets. CONCLUSIONS: Using any of the three intensity-modulated techniques, it is technically feasible to concurrently treat multiple selected high-risk regions within the prostate to 90 Gy and the remaining prostate to 75.6 Gy, while keeping the doses to the rectum and the bladder significantly lower than those associated with a Grade 2 complication rate of 10%.     

Methylamine and monensin do not block insulin internalization but do influence the intracellular distribution and action of insulin in pancreatic acini from diabetic mice

Methylamine and monensin are two agents known to interfere with the recycling of membrane receptors. In the present investigation, we studied their effects on the binding, intracellular distribution, and action of insulin in isolated pancreatic acini prepared from diabetic mice. These drugs had several similar effects on these cells. In a dose-dependent fashion, both increased the amount of [125I]insulin associated with acini. Methylamine approximately doubled and monensin tripled the amount of insulin associated with cells. Employing electron microscope autoradiographs, we observed the accumulation of hormone in large vacuoles in the Golgi-lysosomal area after treatment with methylamine and in smaller swollen Golgi vesicles after treatment with monensin. The influences of both agents on the biological effects of insulin in acini were then investigated. Both agents blocked insulin stimulation of [3H]2-deoxy-D-glucose uptake in acini. The effect of methylamine was also studied on [3H]leucine incorporation into protein and was found to only partially block the effect of insulin. Since insulin and its receptor are internalized, it is likely that the accumulation of insulin in acini induced by these two agents was due to their inhibition of the cellular processing of insulin and its receptor. Moreover, the effects of these two agents to inhibit insulin-stimulated glucose transport may have resulted from either the inhibition of the recruitment of glucose carriers from the Golgi to the plasma membrane or an abnormal interaction of internalized insulin with the Golgi.     

Cerebral venous sinus thrombosis in children: a multicenter cohort from the United States

This study presents a large multicenter cohort of children with cerebral venous thrombosis from 5 centers in the United States and analyzes their clinical findings and risk factors. Seventy patients were included in the study (25 neonates, 35%). The age ranged from 6 days to 12 years. Thirty-eight (55%) were younger than 6 months of age, and 28 (40%) were male. Presenting features included seizures (59%), coma (30%), headache (18%), and motor weakness (21%). Common neurological findings included decreased level of consciousness (50%), papilledema (18%), cranial nerve palsy (33%), hemiparesis (29%), and hypotonia (22%). Predisposing factors were identified in 63 (90%) patients. These included infection (40%), perinatal complications (25%), hypercoagulable/hematological diseases (13%), and various other conditions (10%). Hemorrhagic infarcts occurred in 40% of the patients and hydrocephalus in 10%. Transverse sinus thrombosis was more common (73%) than sagittal sinus thrombosis (35%). Three children underwent thrombolysis, 15 patients received anticoagulation, and 49 (70%) were treated with antibiotics and hydration. Nine (13%) patients (6 of them neonates) died. Twenty-nine patients (41%) were normal, whereas 32 patients (46%) had a neurological deficit at discharge. Seizures and coma at presentation were poor prognostic indicators. In conclusion, cerebral venous thrombosis predominantly affects children younger than age 6 months. Mortality is high (25%) in neonatal cerebral venous thrombosis. Only 18 (25%) patients were treated with anticoagulation or thrombolysis.     

131I lipiodol therapy for unresectable hepatocellular carcinoma

Background : More than 80% of hepatocellular carcinoma tumours (HCC) are unresectable at presentation because of the multicentric nature of the disease or the severity of liver disease. Arterially administered lipiodol is preferentially retained by HCC and has been used as a vehicle for delivery of therapeutic agents to the tumour. The aim of this phase I study is to present the experience with ¹³¹I‐labelled lipiodol in the treatment of unresectable HCC. Methods : ¹³¹Iodine lipiodol treatment was administered to 12 patients with unresectable HCC between 1994 and 1999. The outcome of treatment in these patients was evaluated for survival, clinical tolerance, liver function tests, α‐fetoprotein (AFP) levels and changes in tumour size on computed tomography (CT) scans. Results : Ten of the 12 patients received more than one ¹³¹I treatment. Five patients had treatment for post‐resection recurrence. Serum AFP levels dropped initially in five of the seven patients with elevated values. Tumour size, evaluated by CT scans at 3 months, decreased in six patients and remained stable in the rest, except one patient in whom both the AFP level and tumour size had increased. Using life table analysis, the 50% survival was 19 months. Conclusions : Intra‐arterial ¹³¹I treatment was very well tolerated. A reduction in AFP levels and tumour size occurred in half of the patients and resulted in a 50% probability of survival of 19 months. Further examination of the value of this treatment in phase II and III studies is required.     

Association of lymphomatoid granulomatosis with Epstein-Barr viral infection of B lymphocytes and response to interferon-alpha 2b

Lymphomatoid granulomatosis (LyG) is an angiodestructive lymphoproliferative disorder (LPD) often involving the lungs. Its etiology is uncertain, but a number of previous studies had suggested it is a T-cell LPD associated with Epstein-Barr virus (EBV). Because of the similarity between LYG and nasal angiocentric lymphoma, the term angiocentric immunoproliferative lesion was proposed for both entities. Optimal therapy is unknown, but chemotherapy is often used. We studied four patients with LYG over a 5-year period. Biopsy samples were analyzed by immunohistochemistry, EBV in situ hybridization, and for Ig heavy-chain (IgH) gene rearrangements, Clinically, we assessed EBV serology, lymphocyte subsets, and the efficacy of interferon-alpha2b (IFN-alpha2b), All biopsy samples showed an exuberant T-cell infiltrate with scattered atypical large B cells. Double labeling showed EBV in the B cells but not T cells. Clonal IgH gene rearrangements were detected in 2 of 3 patients studied, 1 of whom had three distinct clones, and light-chain restriction showed two clones in an additional patient. All patients had positive EBV serologies. and markedly abnormal lymphocyte subsets. With IFN, 3 patients are alive and disease free at 36, 43, and 60 months; 1 patient achieved a partial response for 16 months but discontinued therapy and died with lymphoma. These results indicate that LYG is a T-cell-rich EBV-associated B-cell LPD in which the infiltrating T cells are numerous but reactive. IgH gene rearrangements may be polyclonal, monoclonal, or oligoclonal. Its association with immune defects suggests it is related to posttransplant LPD. However, LYG and nasal angiocentric lymphoma are distinct entities and should no longer be included together under the term angiocentric immunoproliferative lesion. IFN is effective therapy and should be studied further.     

Vesicular transport of histamine in stimulated human basophils

Human basophils participating in experimentally produced contact allergy display progressive secretion of electron-dense secretory granule contents and retention of cytoplasmic granule containers in the absence of entire granule extrusion, a process termed piecemeal degranulation (PMD) and postulated to be effected by vesicular transport (Dvorak HF, Dvorak AM: Clin Hematol 4:651, 1975). Proof of this hypothesis was sought using models of human basophil-stimulated secretion, partially purified human peripheral blood basophils, and a morphometric analysis of the fraction of total cellular cytoplasmic vesicles loaded with histamine, a major proinflammatory mediator present in basophil secretory granules. The subcellular localization of histamine was accomplished using a new ultrastructural enzyme-affinity- gold method based on the affinity of diamine oxidase for its substrate, histamine (Dvorak et al: J Histochem Cytochem 41:787, 1993). Two models were selected for a kinetic analysis of stimulated vesicle transport of histamine based on known biochemical and ultrastructural characteristics (MacGlashan et al: J Immunol 136:2231, 1986; Warner et al: J Leukoc Biol 45:558, 1989; Dvorak et al: Am J Pathol 141:1309, 1992; Dvorak et al: Lab Invest 64:234, 1991). These models were selected to include the rapid release reaction stimulated by the bacterial peptide, FMLP, and the slow release reaction stimulated by the phorbol diester tumor promoter, TPA. The results of this study showed that the fraction of histamine-loaded cytoplasmic vesicles (%VG/TV/micron2) in TPA-stimulated basophils significantly exceeded the fraction in unstimulated cells, a process that persisted for 45 minutes after TPA stimulation and was associated with extensive PMD and no morphologic evidence of recovery. Similarly, the fraction of histamine- loaded cytoplasmic vesicles after FMLP stimulation significantly exceeded the fraction in unstimulated cells, a process that persisted for 10 minutes after FMLP stimulation and was associated with the morphologic continuum of PMD-->anaphylactic degranulation (characterized by extrusion of granules)-->recovery, a process largely complete in the 10-minute samples. These studies establish for the first time that an important proinflammatory mediator, histamine, traffic from secretory granules to the extracellular milieu in small cytoplasmic vesicles in stimulated human basophils. The association of this process with the ultrastructural release reaction defined as PMD produced primarily by TPA and in part by FMLP establishes vesicular transport as the mechanism for effecting this type of regulated secretion. Vesicular transport of histamine was also significant in the more complex stimulated secretory and recovery model produced by exposure of human basophils to the bacterial peptide FMLP.