Nitric Oxide-Mediated Toxicity in Paraquat-Exposed SH-SY5Y Cells: A Protective Role of 7-Nitroindazole

The precise mechanism underlying the role of nitric oxide (NO) or nitric oxide synthases (NOSs) in paraquat-mediated toxicity is yet to be fully elucidated. The importance of the NADPH-diaphorase activity of NOSs in paraquat toxicity, in addition to the production of NO, has previously been reported as a mechanism of toxicity. However, other studies have highlighted the toxicity of NO alone and, conversely a protective role of NO in paraquat-mediated toxicity has also been described. The goal of this study was to clarify the involvement of NO and NOS in paraquat-mediated toxicity in an SH-SY5Y cell system, and to evaluate the putative role of 7-nitroindazole as a protective agent in human neural cells. Our results indicate that the three previously described isoforms of NOS are expressed in SH-SY5Y cells, with the data showing that these synthases act as paraquat diaphorases. While this process could occur at the expense of NO production, NO alone does play a toxic role, with its production leading to the formation of the toxicant peroxynitrite. Although the efficacies of the different inhibitors tested cannot be directly compared because the various NOS forms were probably inhibited to differing extents, the results support the idea that endogenous and inducible NO is a neurotoxic mediator of the effects of paraquat. The NADPH-diaphorase activity of NOS and NO production are therefore factors implicated in the toxicity mediated by the herbicide paraquat.     

Hematopoietic growth factor (G-CSF or GM-CSF) after salvage chemotherapy in refractory or relapsed adult de novo acute leukemia

Nineteen adults with primary refractory or relapsed acute leukemia (12 ALL and 7 ANLL) were treated with an intensive salvage chemotherapy (intermediate-dose ara-C, intermediate-dose methotrexate, vindesine, cyclophosphamide, mitoxantrone and prednisolone) followed by a hematopoietic growth factor (HGF), either granulocyte colony-stimulating factor (5 μg/kg) or granulocyte-macrophage colony-stimulating factor (10 μg/kg). Both were given from the day after chemotherapy ended and until the neutrophil count rose above 1 × 10⁹/l for three consecutive days. Eleven patients (58%. 95% CI 33% to 82%) achieved complete remission, and 15 courses of salvage therapy were given to these complete responders. In a historical control group that did not receive HGF, 23 out of 38 patients (60%, 95% CI 44% to 77%) achieved complete remission, and 27 courses of therapy were delivered to complete responders. Treatment with a HGF accelerated the recovery of neutrophils to 0.5 × 10⁹/l significantly, shortening it from a mean of 28 to 22 days (p = .0002), with no effect on platelet recovery. There were no differences in the rates of documented and fatal infections, which were relatively high in both groups. In the patients with ANLL, there was no evidence that HGF accelerated leukemic regrowth. We conclude that HGF accelerates neutrophilic recovery following intensive salvage chemotherapy for acute leukemia, although no reduction in documented infections was found. Many factors, including the small patient sample, may have contributed to this latter finding.     

Susac syndrome as a cause of sensorineural hearing loss

Susac's syndrome is an extremely rare clinical manifestation characterized by the triad of fluctuating sensorineural hearing loss, sudden visual loss and encephalopathy. Probably underdiagnosed, it affects young women who start the clinical history with headache, visual and hearing disturbances, with neurological findings in MRI. With unknown aetiology, pathogenesis is based on arteriolar microinfarcts in retina, cochlea, and grey and white matter in the brain. Treatment is, as stated in the bibliography and our experience, intravenous high doses of steroids followed by oral steroids together with hyperbaric oxygen to minimize ischaemic lesions. Aspirin associate to nimodipine has been useful to date in the treatment of our patient. We present a case and review the existing literature.     

CCR4 versus CCR10 in human cutaneous TH lymphocyte trafficking

The chemokine receptors (CCRs) CCR4 and CCR10, and the cutaneous lymphocyte antigen (CLA), have each been proposed as critical mediators of skin-specific TH lymphocyte homing in mice and humans. CLA initiates skin homing by mediating E-selectin-dependent tethering and rolling within cutaneous venules, but the specific roles of CCR4 and CCR10 are unclear. We have generated an antihuman CCR10 monoclonal antibody (mAb; 1B5) to illuminate the individual contributions of these molecules. This mAb allows us to compare CCR10, CCR4, and CLA expression within human TH populations. The mAb 1B5 recognizes functional CCR10 expression, as chemotactic responsiveness to cutaneous T-cell-attracting chemokine (CTACK)/CCL27 (a CCR10 ligand) parallels the staining of TH subsets. We find CCR10 expressed by only a minority (approximately 30%) of blood-borne, skin-homing (CLA+/CCR4+) TH cells. However, essentially all members of the relatively small "effector" (CLA+/CCR4+/CD27-/CCR7-) skin-homing TH population express CCR10. Most skin-infiltrating lymphocytes in allergic delayed-type hypersensitivity (DTH) and bacterial chancroid skin lesions express both CCR4 and CLA, but only about 10% express CCR10. This suggests for the 2 models of TH skin homing studied here that CCR10+ TH cells have no advantage over other CLA+/CCR4+ TH cells in homing to cutaneous sites. We conclude that the skin-homing TH compartment is itself divided into distinct subpopulations, the smaller of which expresses both CCR4 and CCR10, and the larger of which expresses only CCR4. Thus, CCR10 is unlikely to be necessary for cutaneous homing of TH cells in the models studied here. CCR10 may instead play a role in the movement of specialized "effector" cutaneous TH cells to and/or within epidermal microenvironments.     

Successful medical treatment of two patients with eosinophilic oesophagitis

Background/Purpose: Significant oesophageal eosinophilia is associated with oesophagitis and gastroesophageal reflux (GER). Eosinophilic oesophagitis is a rare disease that causes thickening of the oesophageal wall, narrowing of the oesophageal lumen, and severe motor disturbance. Methods and Results: Two 12 yr-old patients with eosinophilic oesophagitis were studied prospectively. Clinical and investigation details are presented. Elemental formula was administered until complete remission of disease. Final outcome was assessed after 3 months on regular diet with exclusion of specific allergic components. Both patients responded to the dietary manipulation. Conclusions: Eosinophilic oesophagitis must be included in the differential diagnosis when dealing with oesophageal strictures of unknown or unclear aetiology. Elimination diet therapy plays a crucial role in ameliorating the course of the illness. Blood eosinophilia correlates with therapeutic response and with improvement of the disease.     

Iatrogenic secondary post‐partum haemorrhage: Apropos of two uncommon cases

In this article we would like to highlight uterine pseudoaneurysm as a cause of secondary post‐partum haemorrhage following Caesarean section. We would like to stress Doppler ultrasound scan as the initial screening modality for this condition. We also describe angioembolization as the prudent treatment option for this condition rather than resorting to surgery.