医院集中式空调通风系统分区设计与控制院内感染的效应

医院中各种感染源与易感人群同时存在,极易发生医院感染,其中经空气导致的医院感染容易被忽视。分散于空气中的气溶胶与微生物以及运动的微粒是重要的感染传播媒介,而医院集中式空调的通风系统是医院环境中微粒最主要的来源,故此类型通风系统已成为经空气传播医院感染(并非只是呼吸道传染病)的重要传播途径。基于此,认为医院不应设置统一集中的中央空调通风系统,并依据流行病控制原则提出医院空调通风系统“分区”设计,即将医院内的污染区、清洁区、普通区的空调通风系统分别设置,区内根据实际工作需要增设必要的空气过滤设备,以有效控制经空气传播的医院感染发生。     

Hereditary xerocytosis: a report of six unrelated Spanish families with leaky red cell syndrome and increased heat stability of the erythrocyte membrane

Summary. Hereditary xerocytosis (HX) is a rare haemolytic disease due to dehydrated red blood cells (RBCs). A unique feature of this syndrome is that affected members often show normal or near normal haemoglobin levels despite clinical and laboratory evidence of mild to moderate haemolysis. The diagnostic clue is the association of markedly increased RBC Na⁺+K⁺ fluxes with low total cation (Na⁺ +K⁺) content. 11 patients of six unrelated families of Spanish origin with HX have been studied from clinical, genetical and biological points of view. In addition, we have investigated the sensitivity of RBC membrane to heat at three different incubation times (15, 30 and 60min) and two different temperature values (46°C and 49°C). Under these conditions control RBCs (50 normal subjects) exhibited at 49°C and 30min a maximum of 30% fragmented RBCs. This value increased to 80% after 60min of incubation. In contrast, patients with HX showed significantly lower percentages of fragmented RBCs at both 30 and 60min of incubation (maximum 10% and 30%, respectively). In an attempt to determine if increased heat stability was unique to HX RBCs, several other congenital membranopathies with haemolytic anaemia were also studied. The degree of fragmentation, except in one case of HPP (which was strongly increased), did not differ from the control group. Electrophoretic studies of membrane proteins performed in RBCs of all the patients with HX did not explain any qualitative nor quantitative abnormality.
In addition to its physiopathological interest, study of RBC heat stability, together with other haematological parameters (increased MCHC and decreased RBC osmotic fragility), may be useful for HX diagnosis, especially in laboratories which are not equipped to evaluate RBC membrane permeability.     

End-stage periventricular leukomalacia: MR evaluation

A prospective study was performed to assess the capabilities of magnetic resonance (MR) imaging in evaluation of end-stage periventricular leukomalacia (PVL) in six children, aged 31-54 months, in whom PVL had been documented by neurologic ultrasonography during the neonatal period. Eight children of similar age (four premature infants and four full-term infants) with normal neurologic development served as controls. A characteristic triad of PVL abnormalities was seen on MR images: (a) abnormally increased periventricular white-matter signal intensity on the first and second echo images of a T2-weighted sequence (repetition time = 2,000-2,400 msec, echo times = 20 or 30 and 80 msec), most commonly observed in the trigone regions of the lateral ventricles bilaterally; (b) marked loss of periventricular white matter in these regions of abnormal signal intensity, predominantly in the periatrial regions; and (c) compensatory focal ventricular enlargement adjacent to regions of abnormal signal intensity. In patients with the classic periatrial distribution of PVL lesions, general correlation between the degree of neurologic impairment and the severity of MR abnormalities was demonstrated. MR imaging was useful in detecting subtle forms of PVL in cases in which neurologic damage was subclinical.     

Prospective comparative trial of autologous versus allogeneic bone marrow transplantation in patients with non-Hodgkin's lymphoma

A prospective comparative trial of allogeneic versus autologous bone marrow transplant (BMT) was conducted. Sixty-six consecutive patients (median age, 41; range, 15 to 60; female:male ratio = 21:45) entered this clinical trial. Priority for allogeneic BMT was given to patients who were 55 or younger and had a major histocompatibility complex- matched or 1-antigen-disparate sibling donor. Autologous BMT was offered to all other patients whose age was 60 or younger. Patients who had no sibling donor and who had BM involvement at the time of evaluation were not eligible. Thirty-one patients received an allograft, and 35 patients received an autograft. Thirteen patients received a BM graft purged with 4-hydroperoxycyclophosphamide because of previous BM involvement. Patients who had previous radiation to the thoracic and/or abdominal areas of more than 20 Gy received a preparative regimen consisting of cyclophosphamide (1,800 mg/m2/d for 4 days), VP-16 (200 mg/m2 every 12 hours for 8 doses), and 1,3-bis(2- chloroethyl)-1-nitrosourea (600 mg/m2 as 1 dose). Other patients received cyclophosphamide 1,800 mg/m2/d for 4 days followed by total body irradiation of 12 Gy administered as a single daily fraction over 4 days. With a median follow-up of 14 months, the progression-free survival (PFS) for autograft and allograft recipients was 24% +/- 8% (+/- SE) and 47% +/- 9%, respectively, (P = .21). However, the probability of disease progression was significantly higher in the autologous group (69% +/- 9%) than in the allogeneic group (20% +/- 10%; P = .001). When other confounding prognostic factors were adjusted in the multivariate analysis, chemosensitive disease and allograft were found to have a significant favorable influence on probability of disease progression (P = .03 and .003), but only chemosensitive disease had a significant influence on the PFS (P < .002). Our results suggest the existence of graft-versus-lymphoma effect and also support the rationale of using immunotherapy after autologous BMT. Allogeneic BMT should be preferable to autologous BMT in younger patients with lymphoma.     

MORPHOMETRIC APPROACHES TO PERIFASCICULAR ATROPHY IN MUSCLE BIOPSY: DO THEY HELP TO DIAGNOSE POLYMYOSITIS?

The sizes of muscle fibres in the peripheral and central parts of fascicles were compared in biopsies from patients with polymyositis/dermatomyositis, patients with slowly progressing muscular dystrophies and normal controls. Of three quantitative parameters tested, perifascicular atrophy factor gave the best discrimination between the patient groups. This factor is obtained by subtracting the atrophy factor of the peripheral fibres from that of the central ones. In polymyositis, the values tend to be negative as a result of atrophy affecting selectively the peripheral fibres, whereas in dystrophies the values are usually close to zero or positive. For the comparison between polymyositis and muscular dystrophy, the test based on perifascicular atrophy factor has an estimated sensitivity of 83% and a specificity of 65%. This quantitative method is thus able to increase sensitivity of the diagnosis of polymyositis over that attained by the subjective evaluation, even at the cost of a sizeable false-positive rate.