Inaccuracies associated with the automated measurement of mean cell hemoglobin concentration in dehydrated cells

Because of discrepancies between electronically and manually measured values of mean cell hemoglobin concentration (MCHC) encountered in studies of pathologic red cells, we studied the effect of cell water content on MCHC measurements by both methods. A series of red cell samples with varying water contents (54%-164% normal) were prepared from normal cells using the antibiotic nystatin. MCHC was then measured, using the microhematocrit centrifuge and three different electronic cell counters in common laboratory use. For MCHC values above 36 g/dl as measured by the spun hematocrit method, all three electronic counters under estimmated the MCHC, with increasing error as the true MCHC increased. For MCHC values below 30 g/dl, the values from two conductivity based instruments agreed with those from the spun hematocrit method, whereas one instrument based on light scattering overestimated the MCHC. These results indicate that inaccuracies in the measured mean cell volume (MCV) of dehydrated or otherwise undeformable cells may lead to spurious values for MCHC when electronic cell counters are used.     

Failure to express the P-selectin gene or P-selectin blockade confers early pulmonary protection after lung ischemia or transplantation

Endothelial P-selectin expression contributes to the first wave of neutrophil (polymorphonuclear leukocyte; PMN) influx in several inflammatory conditions. Although remote tissue ischemia, such as a crush injury to the hindlimb, may result in P-selectin-mediated pulmonary leukosequestration, it is not known whether the lungs exhibit a similar response after hypothermic preservation or when subjected to a direct ischemic insult. To determine if P-selectin may mediate early primary graft failure, left lungs harvested from male Lewis rats were preserved for 6 hr at 4°C and transplanted orthotopically into isogeneic recipients. Recipients immunodepleted of PMNs before transplantation demonstrated improved graft function; pulmonary vascular resistance was reduced ≈6-fold, arterial oxygenation was increased ≈3-fold, and recipient survival was increased ≈4-fold (P < 0.05, 0.05, and 0.005, respectively). Administration of a blocking anti-P-selectin IgG 10 min before reperfusion diminished graft PMN infiltration and resulted in improved graft function and recipient survival compared with controls. To establish the role of P-selectin in normothermic pulmonary ischemia, mice were subjected to temporary left pulmonary artery ligation. After functional removal of the nonischemic right lung, mice deletionally mutant for the P-selectin gene (P-selectin −/−) exhibited reduced PMN infiltration (≈2-fold), improved arterial oxygenation (≈2-fold), and improved survival (≈3-fold) compared with P-selectin +/+ control mice (P < 0.05, 0.01, and 0.05, respectively). These studies isolate and identify the central role of a single gene product (P-selectin) in early PMN recruitment and tissue injury after frank pulmonary ischemia and in the setting of lung transplantation after hypothermic preservation.     

Dynamic right and left ventricular interactions in the rabbit: Simultaneous measurement of ventricular pressure-volume loops

: This study was performed to characterize the dynamic factors determining ventricular interdependence in an open-pericardium intact animal model. Materials and: Simultaneous measures of right ventricular (RV) and left ventricular (LV) pressures and volumes in 6 urethane-anesthetized openchested, open-pericardium rabbits. RV and LV V were calculated every 2 milliseconds. Measurements were made at initial baseline blood volume, and again after two infusions of 20 mL/kg isoconductive colloid solution. At each blood volume level, partial aortic (AO), pulmonary artery (PAO), and inferior vena caval (IVC) occlusions were performed. Biventricular diastolic compliance and end-systolic elastance were calculated from these data.: Baseline end-diastolic (ED) and end-systolic (ES) V were 3.29 ± 0.55 and 2.43 ± 0.33 mL (x ± SD) for the LV, and 3.38 ± 1.56 and 2.84 ± 1.36 mL for the RV, respectively. AO increased all LV pressure and volume (P < .05) but did not alter RV ED volume (2.85 ± 1.20 mL) or ED pressure (3.3 ± 2.0 to 3.6 ± 2.1 mm Hg). PAO increased RV ES pressure (P < .05) but did not alter RV ED volume, ED pressure, or ES volume, although it decreased LV ED volume (2.82 ± 0.59, P < .05). AO also immediately increased end-systolic RV elastance to a value greater than that defined by IVC (7.9 ± 4.4 to 10.9 ± 6.6 mm Hg/mL, P < .05). Intravascular volume expansion though increasing baseline pressure and volume, did not alter qualitatively biventricular responses to AO, PA, or IVC.: Ventricular interdependence has both systolic and diastolic components that have differing directional effects. In the pericardectomized rabbit, increases in RV ED volume decrease LV ED volume by decreasing LV diastolic compliance, but do not alter LV systolic function. Whereas, increases in LV ED volume decrease RV ES volume resulting in an increase in RV maximal elastance, but minimally alter RV diastolic function.     

小儿淋巴管瘤的MRI诊断

目的分析小儿淋巴管瘤的磁共振表现及其病理基础。方法对６例经手术病理证实的、年龄７天至７岁的小儿淋巴管瘤患者的磁共振表现进行回顾性分析。结果淋巴管瘤磁共振表现为Ｔ１ＷＩ上呈与肌肉相似或稍高的信号，Ｔ２ＷＩ上高于脂肪信号。５例瘤内可见低信号分隔，１例瘤内见血管流空影，３例见明显包膜，３例边界不清。２例病理诊断为海绵状淋巴管瘤，４例诊断为囊状淋巴管瘤。结论磁共振成像可较好地显示肿瘤的大小、形态及范围，从而指导手术治疗。     

Subcutaneous zygomycosis: report of 10 cases from two institutions in North India

Background Subcutaneous zygomycosis is an uncommon condition observed in tropics. Few series have been published, particularly from the northern regions of India. Objectives The aim of this study was to describe clinical, investigative and therapeutic details in subcutaneous zygomycosis observed in two teaching hospitals in Delhi. Patients and methods Ten patients seen over a period of 10 years (1999–2009) form the material for this report. Results There were four children and six adults. In four children, the presentation was a subcutaneous localized mass or gradually spreading plaque. In the others, it was observed over nasal region of face, spreading inward into mucosal sites and paranasal sinuses, and outward to the contiguous areas. Regional lymphadenopathy was present in two with facial lesions. Majority showed a granulomatous infiltrate with admixture of other cells, mainly eosinophils. Aseptate or poorly septate hyphae were observed in seven. In one patient in whom no hyphae were observed, there was dense perivascular inflammation. Organisms were cultured from four patients, Basidiobolus ranarum in two and Syncephalastrum racemosum in two. The main therapy used was a saturated solution of potassium iodide (KI). Four received only KI of which two attained cure after 3 months and 9 months respectively, and the other two showed signs of regression. In one boy subsidence was associated with reduced circumference of thigh. Ketoconazole or itraconazole was given with KI to hasten regression when response was slow or there were side‐effects to KI. Conclusion Awareness and early recognition will prevent disfigurement produced by advanced disease, misdiagnosis and unnecessary surgical intervention.     

Toward a better ventilation strategy for patients with acute lung injury

Ventilator-induced lung injury is a major outcome determinant of the acute respiratory distress syndrome (ARDS). Ventilatory strategies that limit ventilator-induced lung injury should improve outcome from ARDS. The ARDSnet trial showed improved survival in subjects ventilated with a lower tidal volume. Although this trial developed and tested a rigorous clinical protocol, it did not define the limits to which tidal volume reduction would benefit outcome. It is also not at all clear if it is the reduction in tidal volume or the reduction in plateau airway pressure that confers this benefit. Finally, ventilator-induced lung injury occurs more commonly from repetitive collapse and re-expansion of injured lung units rather than from the overdistention of persistently aerated lung units. This was not addressed in the trial design. Thus, further study using targeted open-lung strategies are also needed.     

Pharmacologic therapy for fetal arrhythmias

Although great strides have been made in diagnosing fetal cardiac anatomic and functional abnormalities, in utero cardiac therapy is limited to the treatment of significant arrhythmias. The fetal prognosis may change if the dysrhythmia persists or if the condition results in intrauterine heart failure. When either complication is evident, intrauterine drug therapy may be indicated if the fetus is considered too immature for delivery. Information from case reports has shown several drugs to be useful to cardiovert the fetus, with digitalis being the pharmacologic agent used most often. At present, treatment consists mainly of transplacental administration of antiarrhythmic agents with the object of normalizing FHR and rhythm and abolishing, or preventing, fetal cardiac failure. Various agents have been used with variable success. More direct fetal therapy by intramuscular injection or umbilical vein infusion may replace unsuccessful indirect maternal therapy. It is unclear why some fetuses respond (or appear to respond) and others have hydrops and die in the absence of congenital heart disease or documented infection. With proper therapy, many fetuses survive and have a satisfactory prognosis, depending on the form of arrhythmia and the nature of any cardiac structural defects.