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We examined the baseline features and clinical outcomes of 140 patients presenting with JAK2V617F positivity and a bone marrow morphology conforming with WHO criteria of polycythemia vera (PV), but a hemoglobin level of <18.5 g/dL in males (range 16.0–18.4) and <16.5 g/dL in females (range 15.0–16.4). This cohort operationally referred to as masked PV (mPV) was compared with 257 patients with overt PV and displayed male predominance, a more frequent history of arterial thrombosis and thrombocytosis. Incidence of thrombosis was similar between the two groups but mPV displayed significantly higher rates of progression to myelofibrosis and acute leukemia and inferior survival. In multivariable analysis mPV diagnosis was an independent predictor of poor survival along with age >65 years and leukocyte count >10 × 109/L. Our data suggest that mPV is a heterogeneous myeloproliferative neoplasia and not necessarily an early/ pre‐polycythemic form of classical PV that at onset in a small fraction of patients clinically may mimic essential thrombocythemia. On the other hand, the majority mPV may have a longer prodrome of undiagnosed PV or a disease biology akin to primary myelofibrosis‐post PV myelofibrosis that could explain the worsening of outcome in comparison to overt/classical manifestations. Am. J. Hematol. 89:52–54, 2014. © 2013 Wiley Periodicals, Inc.

ObjectivesTo 1) describe and validate an ultrasound‐guided ischial bursa injection technique in an unembalmed cadaveric model and 2) to compare the distance between the ischial tuberosity and the sciatic nerve in a hip neutral versus 90° flexed hip position in asymptomatic volunteers.DesignThe first part was a single‐blind prospective study. The second part was a prospective cohort study.SettingAn academic institution procedural skills laboratory and outpatient clinic.ParticipantsThe first part of the study involved 1 cadaveric specimen. The second part of the study involved 20 asymptomatic subjects. The mean age of the subjects was 28 years, and the mean (standard deviation) body mass index was 23.2 ± 2.8 kg/m2 (minimum, 18.3 kg/m2; maximum, 29.5 kg/m2).MethodsIn the first part of the study, a single operator completed bilateral ultrasound‐guided ischial bursa injections in an unembalmed cadaveric specimen by using diluted colored latex. In the second part of the study, ultrasound was used in 20 asymptomatic volunteer subjects (10 men and 10 women) to measure the distance from the lateral edge of the ischial tuberosity to the sciatic nerve.Main Outcome MeasurementsThe injections were graded for accuracy as follows: accurate (all injectate contained within the ischial bursa), accurate with overflow (injectate within the ischial bursa but also located in adjacent structures other than the needle track), or inaccurate (injectate not within the ischial bursa). The second part of the study measured the distance from the ischial tuberosity to the sciatic nerve with subjects in 2 different positions (prone and side lying with the tested hip flexed to 90°).ResultsPostinjection cadaveric dissections revealed that both ultrasound‐guided injections accurately placed liquid latex within the ischial bursae. There was no evidence of injury to surrounding neurovascular structures. Among asymptomatic volunteers, the average distance between the ischial tuberosity and the sciatic nerve increased from 28.4 mm (range, 20.5‐38.9 mm) in the neutral position to 41.9 mm (range, 30.9‐66.0 mm) with the hip flexed to 90° (average change, 13.5 mm away from the ischial tuberosity; P = .0001).ConclusionsUltrasound‐guided ischial bursa injections are technically feasible. Flexing the hip to 90° increases the distance between the ischial tuberosity and the sciatic nerve in asymptomatic volunteers, thus potentially resulting in a safer needle trajectory when ischial bursa injections are clinically indicated. Further investigation in clinical settings is warranted to validate these findings.

The purpose of this study was to characterize changes in antioxidant and age-related gene expression in aorta and aortic valve with aging, and test the hypothesis that increased mitochondrial oxidative stress accelerates age-related endothelial and aortic valve dysfunction. Wild-type (MnSOD+/+) and manganese SOD heterozygous haploinsufficient (MnSOD+/−) mice were studied at 3 and 18 mo of age. In aorta from wild-type mice, antioxidant expression was preserved, although there were age-associated increases in Nox2 expression. Haploinsufficiency of MnSOD did not alter antioxidant expression in aorta, but increased expression of Nox2. When compared with that of aorta, age-associated reductions in antioxidant expression were larger in aortic valves from wild-type and MnSOD haploinsufficient mice, although Nox2 expression was unchanged. Similarly, sirtuin expression was relatively well-preserved in aorta from both genotypes, whereas expression of SIRT1, SIRT2, SIRT3, SIRT4, and SIRT6 were significantly reduced in the aortic valve. Expression of p16ink4a, a marker of cellular senescence, was profoundly increased in both aorta and aortic valve from MnSOD+/+ and MnSOD+/− mice. Functionally, we observed comparable age-associated reductions in endothelial function in aorta from both MnSOD+/+ and MnSOD+/− mice. Interestingly, inhibition of NAD(P)H oxidase with apocynin or gp91ds-tat improved endothelial function in MnSOD+/+ mice but significantly impaired endothelial function in MnSOD+/− mice at both ages. Aortic valve function was not impaired by aging or MnSOD haploinsufficiency. Changes in antioxidant and sirtuin gene expression with aging differ dramatically between aorta and aortic valve. Furthermore, although MnSOD does not result in overt cardiovascular dysfunction with aging, compensatory transcriptional responses to MnSOD deficiency appear to be tissue specific.

Mechanical ventilation may cause harm by straining lungs at a time they are particularly prone to injury from deforming stress. The objective of this study was to define the relative contributions of alveolar overdistension and cyclic recruitment and “collapse” of unstable lung units to membrane wounding of alveolar epithelial cells. We measured the interactive effects of tidal volume (V T ), transpulmonary pressure (P TP ), and of airspace liquid on the number of alveolar epithelial cells with plasma membrane wounds in ex vivo mechanically ventilated rat lungs. Plasma membrane integrity was assessed by propidium iodide (PI) exclusion in confocal images of subpleural alveoli. Cyclic inflations of normal lungs from zero end-expiratory pressure to 40 cmH 2 O produced V T values of 56.9 ± 3.1 ml/kg and were associated with 0.12 ± 0.12 PI-positive cells/alveolus. A preceding tracheal instillation of normal saline (3 ml) reduced V T to 49.1 ± 6 ml/kg but was associated with a significantly greater number of wounded alveolar epithelial cells (0.52 ± 0.16 cells/alveolus; P < 0.01). Mechanical ventilation of completely saline-filled lungs with saline (V T = 52 ml/kg) to pressures between 10 and 15 cmH 2 O was associated with the least number of wounded epithelial cells (0.02 ± 0.02 cells/alveolus; P < 0.01). In mechanically ventilated, partially saline-filled lungs, the number of wounded cells increased substantially with V T , but, once V T was accounted for, wounding was independent of maximal P TP . We found that interfacial stress associated with the generation and destruction of liquid bridges in airspaces is the primary biophysical cell injury mechanism in mechanically ventilated lungs.

Inflammatory cap polyposis (ICP) is a rare nonneoplastic polyposis of the colon of unknown etiology that can be confused with prolapse-induced polyps and hyperplastic polyposis. We contribute a case of ICP from a 59-year-old woman who was affected by severe constipation and hematochezia. Numerous sessile and semipedunculated polyps were found in the colon, all with cap of whitish fibrin. Histology revealed erosion of the surface, superficial dilated crypts filled with mucoid inflammatory exudate, and minimal crypt serration, all findings typical of ICP. Only the largest polyps had smooth muscle in the mucosa. Ki-67 showed modest expansion and irregular distribution of the crypts proliferative areas. Low-degree positivity for p16, similar to that of hyperplastic polyps, was found. CK20 was expressed as in normal mucosa. Distinguishing between ICP and other polyposis is important because of difference in management.

CTGF (connective tissue growth factor) is widely regarded as an important amplifier of the profibrogenic action of TGF-β (transforming growth factor β) in a variety of tissues, although the precise mechanism of how the TGF-β signalling pathways modulate CTGF expression remains unclear. In the present study, the role of PKCδ (protein kinase Cδ) in TGF-β1-mediated CTGF expression was investigated using HepG2 cells. TGF-β1 treatment specifically elevated PKCδ activation and CTGF expression. In contrast, blockade of PKCδ by the selective inhibitor Rottlerin or by siRNA knockdown significantly reduced TGF-β1-induced CTGF production. The regulatory mechanism was further demonstrated in HepG2 cells whereby TGF-β1-induced PKCδ activation negatively regulated the nuclear levels of PPM1A (protein phosphatase, Mg2+/Mn2+ dependent, 1A) through the RhoA/ROCK (Rho-associated kinase) pathway. Moreover, we showed that both Smad signalling and the PKCδ pathway appeared to be stimulated by TGF-β1 in parallel. Time course assessments indicated that PKCδ signalling may have a function in maintaining nuclear phospho-Smads at a maximal level. The collective results of the present study demonstrated that PKCδ-stimulated RhoA/ROCK activation resulted in a reduction in PPM1A, thereby up-regulating Smad-dependent gene induction for extended periods. These findings indicated that PKCδ plays a critical role in TGF-β1-induced CTGF production in HepG2 cells.

Background and Purpose— Phosphorylation of eNOS, an important post-translational modulator of its enzymatic activity, is reduced in diabetes mellitus. We hypothesized that modulation of eNOS phosphorylation could overcome diabetic vascular dysfunction and improves the outcome to stroke. Methods— We used the db/db mouse model of type 2 diabetes mellitus. We mated db/db mice with eNOS knock-in mice that carry single amino acid mutations at the S1176 phosphorylation site; the phosphomimetic SD mutation (serine replaced by aspartate) shows increased eNOS enzymatic activity, whereas the unphosphorylatable SA mutation (serine replaced by alanine) shows decreased eNOS activity. We characterized the vascular anatomy, baseline physiological parameters, and vascular reactivity. We used the middle cerebral artery occlusion model of stroke and measured infarct volume and neurological deficits. Results— db/db mice showed diminished eNOS phosphorylation at S1176. eNOS SD and SA mutations do not change the vascular anatomy at the Circle of Willis, brain capillary density, heart rate, or arterial blood gases of db/db mice. The eNOS SD mutation, but not the SA mutation, lowers blood pressure and improves vascular reactivity to acetylcholine in db/db mice. The eNOS SD mutation reduces stroke size and neurological deficit after middle cerebral artery occlusion. Conclusions— Diminished eNOS phosphorylation is a mechanism of vascular dysfunction in db/db mice. We show here that modulation of the eNOS S1176 phosphorylation site in db/db mice is associated with improved vascular reactivity and improved outcome to stroke after middle cerebral artery occlusion.