Citations

AbstractA somatic mutation in the JH2 autoinhibitory domain of the Janus kinase 2 (JAK2) tyrosine kinase was recently described in polycythemia vera, essential thrombocythemia, and myelofibrosis with myeloid metaplasia. The prevalence of this mutation in either “atypical” myeloproliferative disorders (MPDs) or the myelodysplastic syndromes (MDSs) is unknown. Bone marrow–derived genomic DNA from 245 patients—119 with chronic myelomonocytic leukemia (CMML), 101 with MDS, 11 with hypereosinophilic syndrome (HES), 8 with systemic mastocytosis (SM), and 6 with chronic neutrophilic leukemia (CNL)—was screened for the JAK2 V617F mutation. A mutant allele was detected in 11 patients: 3 with CMML (3%), 5 with MDS (5%), 2 with SM, and 1 with CNL. Interestingly, one of the patients with SM and the patient with CNL with JAK2 V617F had a history of lymphoma, and this patient with SM also had associated myelofibrosis and CMML. The current observation strengthens the specific association between JAK2 V617F and classic MPD, but also suggests an infrequent occurrence in other myeloid disorders.

Purpose Epothilones are a new class of nontaxane tubulin polymerization agents that have activity in taxane-resistant tumors. Epothilone B (BMS-247550) is a semisynthetic analog of the natural product epothilone B. This study was performed to determine the activity of BMS-247550 in patients with soft tissue sarcomas (STSs) who had not received prior chemotherapy for metastatic disease. Patients and Methods Patients with measurable, advanced, or metastatic STS with no prior chemotherapy for metastatic disease were treated with BMS-2457550 50 mg/m 2 intravenously during 1 hour every 21 days. All responses were confirmed 4 weeks later. Results Thirty-one patients (median age, 54 years; range, 19 to 78 years; 48% female) were entered onto the trial and were assessable for response. All but one patient had an Eastern Cooperative Oncology Group performance score of 0% or 1%, and 39% had received prior adjuvant chemotherapy. Mean follow-up was 22 months, with a confirmed response rate of 6% (95% CI, 0% to 17%). Median time to progression was 4.5 months (95% CI, 1.9 to 8.3 months), and 1 year progression-free survival was 17% (95% CI, 8% to 38%). Median survival was 16.4 months, with a 1-year survival of 61% (95% CI, 46% to 81%). Toxicity was mainly hematologic, with eight of 31 (26%) patients experiencing grade 3 to 4 leukopenia; 15 of 31 patients (48%) experienced grade 3 to 4 neutropenia. The grade 3 to 4 nonhematologic toxicities included neuropathies (26%), myalgia (13%), and fatigue (10%). Conclusion BMS-247550 has limited activity against STSs when given in this dose and schedule. The clinical toxicity is similar to that of taxanes.

AbstractThe results and complications of neurovascular operations in one surgeon's experience during the era of the operating microscope are reviewed in the framework of the pathophysiology of the illness for which they were performed. Overall mortality rate was 5% and morbidity rate 11% in 405 patients with intracranial aneurysms. Morbidity and mortality varied according to preoperative neurological function, location and size of aneurysm, and number of days from last subarachnoid hemorrhage to surgery. Although a delay in operation improved the operative results, there were significant mortality and morbidity among patients awaiting surgery. There were immediate and delayed ischemic complications. In the former group (7% of cases), the cause was clearly attributable to surgical trauma, such as damage to perforating vessels and major vessel occlusion, which was related to size and location of the aneurysm and unrelated to the patient's neurological function or timing of surgery. Delayed ischcmic complications, minor and reversible in 10% of patients, severe in 5%, were related to preoperative neurological function and timing of surgery. These did not occur in any patients operated on for a mass effect from the aneurysm without a subarachnoid hemorrhage.The overall combined major morbidity and mortality for carotid endarterectomy in 681 patients in whom the microscope was not used was 2%, but varied according to medical, neurological, and angiographically determined risk factors. Patients were seldom operated on for lesions that did not produce at least a 70–80% stenosis unless there was angiographie evidence of severe ulccration. All patients were monitored intraoperatively with cerebral blood flow measurements and a continuous electroencephalogram. Retinal artery pressure measurements were performed pre‐operatively and postoperatively. The relationship of these monitoring techniques to the pathophysiology of ischemic symptomatology is reviewed.Preliminary evaluation of 149 extracranial to intracranial bypass procedures for occlusive disease of the carotid system, and of 22 procedures for occlusive disease in the vertebral‐basilar system indicates a patency rate of 95% and 90%, respectively. The effectiveness of these operations was related to the symptomatology for which they were performed. The overall combined morbidity and mortality was 5%, but varied according to preoperative neurological function.There were 59 operations for cerebral arteriovenous malformations (AVM) (38 parenchymal, 1 death; 21 durai, 1 death). Low morbidity and mortality rates were achieved in parenchymal AVMs by not operating on large lesions or those with a thalamic component and, therefore, these results must be placed in that perspective. This conservative approach was justified by the current lack of information concerning the natural history of this illness. In contrast, virtually all durai AVMs were eventually operated on because of the progressive nature of this acquired illness.

Abstract We hypothesized that the presence of monoclonal free kappa or lambda immunoglobulin light chains in monoclonal gammopathy of undetermined significance (MGUS), as detected by the serum free light chain (FLC) assay increases the risk of progression to malignancy. Of 1384 patients with MGUS from Southeastern Minnesota seen at the Mayo Clinic from 1960 to 1994, baseline serum samples obtained within 30 days of diagnosis were available in 1148. At a median follow-up of 15 years, malignant progression had occurred in 87 (7.6%) patients. An abnormal FLC ratio (kappa-lambda ratio < 0.26 or > 1.65) was detected in 379 (33%) patients. The risk of progression in patients with an abnormal FLC ratio was significantly higher compared with patients with a normal ratio (hazard ratio, 3.5; 95% confidence interval [CI], 2.3-5.5; P < .001) and was independent of the size and type of the serum monoclonal (M) protein. Patients with an abnormal serum FLC ratio, non–immunoglobulin G (non-IgG) MGUS, and a high serum M protein level (≥ 15 g/L) had a risk of progression at 20 years of 58% (high-risk MGUS) versus 37% with any 2 of these risk factors (high-intermediate risk), 21% with one risk factor (low-intermediate risk), and 5% when none of the risk factors were present (low risk).

The defining features of the widely conserved HtrA (high temperature requirement) family of serine proteases are the combination of a catalytic protease domain with one or more C-terminal PDZ domains and reversible zymogen activation. Even though HtrAs have previously been implicated in protein quality control and various diseases, including cancer, arthritis, and neuromuscular disorder, the biology of the human family members is not well understood. Our data suggest that HtrA1 is directly involved in the β-amyloid pathway as it degrades various fragments of amyloid precursor protein while an HtrA1 inhibitor causes accumulation of Aβ in astrocyte cell culture supernatants. Furthermore, HtrA1 colocalizes with β-amyloid deposits in human brain samples. Potential implications in Alzheimer's disease are discussed.

Dynamic membrane protrusions such as lamellipodia and filopodia are driven by actin polymerization and often hijacked by intracellular microbes to enter host cells. The overall rate of membrane protrusion depends on the actin polymerization rate and the increase of localized cell volume. Although the signaling pathways involving actin polymerization are well characterized, the molecular mechanisms regulating local cell volume associated with membrane protrusion are unclear. Cryptosporidium parvum , an intracellular parasite, depends on host-cell membrane protrusion to accomplish cell entry and form the parasitophorous vacuole. Here, we report that C. parvum infection of cholangiocytes recruits host-cell SGLT1, a Na + /glucose cotransporter, and aquaporin 1 (AQP1), a water channel, to the attachment site. SGLT1-dependent glucose uptake occurs at the attachment site. Concordantly, the region of attachment displays localized water influx that is inhibited by either suppression of AQP1 by means of AQP1-small interfering RNA (siRNA) or inhibition of SGLT1 by a specific pharmacologic inhibitor, phlorizin. Inhibition of SGLT1 does not affect actin accumulation but decreases the membrane protrusion at the attachment site. Moreover, functional inhibition of host-cell AQP1 and SGLT1 hampers C. parvum invasion of cholangiocytes. Thus, glucose-driven, AQP-mediated localized water influx is involved in the membrane protrusion during C. parvum cellular invasion, phenomena that may also be relevant to the mechanisms of cell membrane protrusion in general.