On the development of CNS lesions in natural canine distemper encephalomyelitis

Acute lesions within spinal cord white matter have been studied by light and electron microscopy in 3 dogs suffering from the acute form of canine distemper encephalomyelitis (CDE). Prominent features of these lesions were viral inclusions, giant cell formation, cellular degeneration, myelin breakdown and phagocytic activity by cells believed to be derived from local glia. The viral inclusions occurred in giant cells, many astrocytes, macrophages and occasional oligodendroglia. Only suggestions of active viral replication from cell membranes were present. On the basis of the above features, these CDE lesions were classed as being acute. Perivascular inflammation and parenchymal invasion by haematogenous cells were lacking. However, older, gliotic, demyelinated lesions were always associated with inflammation. The pattern of demyelination in acute CDE lesions differed from those seen in other conditions, in particular the autoimmune demyelinating diseases. In acute CDE lesions, individual fibres became separated from others by rings of cells, the processes of which systematically stripped the myelin from the outer layers of the sheath inwards until a naked segment of axon remained. Some of the macrophages were recognisable as astroglia. Elsewhere, unequivocal astrocytes containing myelin debris were common. The results suggest that inflammation in acute CDE lesions is not a primary event, and that viral invasion causes breakdown of tissue which is accompanied pari passu by myelin destruction. The latter might be related to the non-specific release of host factors (viz. hydrolytic enzymes) or humoral factors during the cellular degeneration. Local cells appeared to participate in the process of myelin phagocytosis. Overt inflammation and damage by haematogenous cells were features only of chronic lesions and have been described previously in studies on chronic CDE lesions. The results are interpreted in terms of their relevance to the study of human subacute sclerosing panencephalitis, of which CDE is considered the animal analogue, and multiple sclerosis, the paradigm of the human demyelinating diseases.     

Health surveillance for asthma in the US Navy: experience of 9,185,484 person-years

PURPOSE: To measure trends and demographic risk factors for hospitalization for asthma. METHODS: Time trends and demographic risk factors, for hospitalized asthma (1CD-9-CM Code 493) were analyzed by measuring age-specific and age-adjusted first hospitalization rates in a defined population of active-duty enlisted members of the US Navy worldwide during 1980-1999, consisting of 9,185,484 person-years. RESULTS: There were 3911 patients first hospitalized for asthma, including 2916 men and 995 women. The age-adjusted incidence rate of first hospitalization for asthma was three times higher in women than men, 110 per 100,000 person-years (95% confidence interval [CI], 104-117), compared with 35 per 100,000 person-years (95% CI, 33-37), respectively (p < 0.0001). The rate in black women was twice as high as in white women, 186 per 100,000 person-years, compared with 99 per 100,000 person-years, respectively (p < 0.001). The rate in black men was higher than in white men, 45 per 100,000, compared with 34 per 100,000 (p < 0.001). Age-adjusted rates in women doubled from 73 per 100,000 in 1980-1983 to 159 in 1997-1999 (p for trend < 0.01), while those in men remained stable. CONCLUSIONS: Age-adjusted incidence rates of first hospitalization for asthma were three times as high in women as in men, and doubled during the period between 1980 and 1999. The rates in black women were twice as high as in white women. The reasons are unknown.     

Real-time intra-fraction-motion tracking using the treatment couch: a feasibility study

Significant differences between planned and delivered treatments may occur due to respiration-induced tumour motion, leading to underdosing of parts of the tumour and overdosing of parts of the surrounding critical structures. Existing methods proposed to counter tumour motion include breath-holds, gating and MLC-based tracking. Breath-holds and gating techniques increase treatment time considerably, whereas MLC-based tracking is limited to two dimensions. We present an alternative solution in which a robotic couch moves in real time in response to organ motion. To demonstrate proof-of-principle, we constructed a miniature adaptive couch model consisting of two movable platforms that simulate tumour motion and couch motion, respectively. These platforms were connected via an electronic feedback loop so that the bottom platform responded to the motion of the top platform. We tested our model with a seven-field step-and-shoot delivery case in which we performed three film-based experiments: (1) static geometry, (2) phantom-only motion and (3) phantom motion with simulated couch motion. Our measurements demonstrate that the miniature couch was able to compensate for phantom motion to the extent that the dose distributions were practically indistinguishable from those in static geometry. Motivated by this initial success, we investigated a real-time couch compensation system consisting of a stereoscopic infra-red camera system interfaced to a robotic couch known as the Hexapod, which responds in real time to any change in position detected by the cameras. Optical reflectors placed on a solid water phantom were used as surrogates for motion. We tested the effectiveness of couch-based motion compensation for fixed fields and a dynamic arc delivery cases. Due to hardware limitations, we performed film-based experiments (1), (2) and (3), with the robotic couch at a phantom motion period and dose rate of 16 s and 100 MU min(-1), respectively. Analysis of film measurements showed near-equivalent dose distributions (相似文献   

Online therapy: review of relevant definitions, debates, and current empirical support

The current article reviews the most recent literature addressing the definitions, ethical considerations, and potential strengths and limitations of online therapy. In addition, a framework is provided for how to conceptualize and categorize different aspects of online therapy for research purposes. Relevant studies of both online and face-to-face therapy as well as suggestions for future research are outlined.     

En bloc vs transhiatal esophagectomy for stage T3 N1 adenocarcinoma of the distal esophagus

HYPOTHESIS: En bloc esophagectomy (EBE) provides improved survival over transhiatal esophagectomy (THE) in patients with similarly sized transmural tumors (T3) and lymph node metastases (N1). DESIGN: A retrospective case-control study of 2 methods of esophageal resection for cancer. SETTING: University hospital (tertiary referral center for esophageal disease). PATIENTS: There were 49 patients (27 who underwent EBE and 22 who underwent THE) with similar T3 N1 disease and the following matched criteria: tumors of similar size and location, more than 20 lymph nodes in the surgical specimen, R0 resection, no previous chemotherapy or radiation therapy, and follow-up until death or for a minimum of 5 years.Main Outcome Measure Survival adjusted for differences in demographic and patient characteristics. RESULTS: The number of nodes harvested was greatest after EBE vs THE (median, 52 vs 29 [range, 21-85 vs 20-60]; P<.001). The median number of involved nodes was similar after EBE vs THE (median, 5 vs 7 [range, 1-19 vs 1-16]). The only 2 independent factors that affected survival in a Cox analysis were the number of involved lymph nodes (P =.01) and the type of resection (P =.03). Patients who underwent EBE had a survival benefit over those who underwent THE (P =.01). The survival benefit of EBE was seen only in patients with fewer than 9 involved lymph nodes (P<.001). CONCLUSION: En bloc esophagectomy confers a better survival than THE in patients with T3 N1 disease and fewer than 9 lymph node metastases.     

Lymphadenectomy prior to rat hind limb allotransplantation prevents graft-versus-host disease in chimeric hosts

In previous rat studies, the use of mixed allogeneic chimerism (MAC) to induce host tolerance to hind limb allografts has resulted in severe graft-versus-host disease (GVHD). The purpose of this study was to determine if immunocompetent cells in bone marrow (BM) and/or lymph nodes (LNs) of transplanted limbs were responsible for inducing GVHD in mixed chimeric hosts. [ACIWistar Furth] chimeric rats received ACI hind limbs that were non-irradiated, irradiated (1050 cGy) or lymphadenectomized. Rejection, GVHD and donor chimerism was assessed. Chimeric hosts rejected none of their limbs. However, hosts of non-irradiated hind limbs succumbed to GVHD 22.4±0.8 days after transplantation. In contrast, chimeras that received irradiated or lymphadenectomized ACI hind limbs showed no clinical or histological signs of GVHD at 5 months. We conclude that mixed chimeric hosts are susceptible to GVHD due to the immunocompetent cell load provided by the LNs, not the BM, of hind limb allografts.Abbreviations BM Bone marrow - CPM Counts per minute - CTA Composite tissue allograft - FACS Fluorescence activated cell sorter - FITC Fluorescent iso-thiocyanate - GVH Graft-versus-host - GVHD Graft-versus-host disease - HVG Host-versus-graft - LN Lymph node - MAC Mixed allogeneic chimerism - MHC Major histocompatibility complex - MLR Mixed lymphocyte reaction - MoAb Monoclonal antibody - PBL Peripheral blood lymphocytes - SEM Standard error of mean - TBI Total body irradiation - TCD T-cell depletion/T-cell depleted - TCR T-cell receptor     

Interaction between adenosine and allergen or compound 48/80 on lung parenchymal strips from actively sensitized Brown Norway rats

We have investigated the effect of mast cell activation induced by immunological and non-immunological stimuli on the sensitivity to adenosine of parenchymal strips prepared from lungs removed from Brown Norway (BN) rats actively sensitized to ovalbumin. Strips responded to ovalbumin with a biphasic contractile response. Responses to adenosine were markedly increased 30 min after ovalbumin. The first phase of the response to ovalbumin was abolished by the 5-hydroxytryptamine (5-HT)2 receptor antagonist, methysergide and unaffected by the cysteinyl leukotriene receptor antagonist, iralukast. The second phase was abolished by iralukast and unaffected by methysergide. The response to adenosine was markedly reduced by methysergide but not significantly altered by iralukast. Compound 48/80 (condensation product of N-methyl-p-methoxyphenylethylamine with formaldehyde) induced methysergide-sensitive contractions of the parenchymal strip and potentiated adenosine; the augmented response to adenosine was blocked by methysergide. Thus, activation of mast cells in the lung by either immunological or non-immunological stimuli results in augmentation of the mast cell-mediated contractile response to adenosine.