Nitric oxide synthesis in the in vivo allograft response: a possible regulatory mechanism.

Activated macrophages are known to oxidatively metabolize L-arginine to nitric oxide and citrulline. We have recently shown that nitric oxide is a potent inhibitory molecule in the in vitro rat mixed-splenocyte culture, resulting in inhibition of proliferation and cytolytic T-cell induction. We undertook this study using the sponge matrix allograft model in the rat to determine whether nitric oxide plays a role in an in vivo allograft response. Our experiments showed that on day 6 after grafting, when cytolytic activity of allograft-infiltrating cells is first detected, allogeneic graft fluid contains higher levels of NO2-/NO3- (the stable endproducts of nitric oxide metabolism) than syngeneic graft fluid. Furthermore, evaluation of the supernatants of cultured graft-infiltrating cells revealed that allogeneic graft-infiltrating cells spontaneously produce higher amounts of nitric oxide than syngeneic graft-infiltrating cells. The nitric oxide production was inhibited in the presence of NG-monomethyl-L-arginine (NMA), the competitive inhibitor of nitric oxide production. Most of the nitric oxide production was observed in the adherent macrophage fraction of the allograft-infiltrating cells. When allograft-infiltrating cells were cultured in the presence of NMA, donor-specific cytolytic activity was observed, whereas allograft-infiltrating cells cultured in the absence of NMA showed no cytolytic activity. These data show that nitric oxide production may play an important regulatory role in the allograft response.     

The psychometric properties of the Behaviour Assessment Record (the BAR schedule)

ABSTRACT. Two hundred and forty-seven completed Behaviour Assessment Records (BAR) for people with learning difficulties living in hospital, community residential facilities or the family home were subjected to item analysis and factor analysis. The instrument as a whole proved to be highly internally consistent, although the corrected item-total correlation coefficients suggest the redundancy of some items on individual sub-scales. Factor analysis produced a two-factor solution accounting for 32–9 and 10–8% of the variance. These factors were named Personal self-care and Use of public amenities. Summative scales based upon these factors were highly internally consistent. Comparisons are made between the internal consistency and factor structure of the BAR and those of similar measures of adaptive behaviour, such as the Social Training Achievement Record (Sturmey et al. , 1988), the Pathways to Independence Checklist (Walsh & McConkey, 1989), and the Adaptive Behavior Scale (Nihira, 1969a, b, 1976).     

The impact of a patient education program on directed donations

The effect of an informational program in which the benefits and disadvantages of directed donations are discussed directly with the prospective recipient of the blood and/or that patient's family was examined during a 20-month period. Data collected for 27 regional Connecticut hospitals that accept directed donations were compared with similar data for Hartford Hospital, an 885-bed tertiary-care facility. The number of directed-donor units (68) collected by the American Red Cross Blood Services for Hartford Hospital during the study period was comparable to the number (average, 62.3) provided for smaller (301-450 beds) institutions in the state. The percentage that directed-donor units drawn for Hartford Hospital represented of the total number of homologous units provided (0.23%) was less than that for any of the categories of hospitals, by size, in the state. Supplying the patient and/or the patient's family, in a personalized manner, with information concerning the advantages and disadvantages of directed as well as of volunteer donor blood can result in a marked overall reduction in the number of directed donations and also serves to reassure those concerned about blood transfusion.     

Computer-assisted analysis of wall motion of the right ventricle in a normal patient sample and diagnosis of right heart infarction using transesophageal echocardiography

Using 2D and M-Mode transesophageal short axis cross sections, right ventricular systolic wall motion was quantified in 15 normal patients. A further group of 39 patients with right ventricular infarction was investigated. In the normal group fractional shortening of the septum was -19.6% (-45 to 8%), that of the lateral wall 51.6% (37 to 73%), of the posterior wall 33.9% (5 to 50%) and of the anterior wall 42.7% (18 to 57%). Right ventricular infarction (RVI) was associated in 33 patients with posterior left ventricular infarction (85%) and in three patients with anterior infarction. In two cases only an isolated RVI was found. Right ventricular dilation occurred in 24 patients (61%). Hemodynamic criteria were fulfilled in eleven out of 21 patients (53%). RVI was confirmed in one patient by surgery and in ten patients by autopsy. Recognition of regional wall motion abnormalities by transesophageal echocardiography permits an accurate bedside identification of RVI. 2D and M-Mode registration of the short axis improves RVI assessment. Wall motion analyses offer the possibility to determine the extent of right ventricular infarction.     

Lung mechanics--the inverse problem.

The mechanical properties of the lung are important determinants of its efficacy as a gas exchanging organ. These properties are reflected to a precise degree in the relationships between pressure and flow measured at the mouth. Together with oesophageal pressure, which reflects the pressure in the pleural space, these quantities allow one to usefully indulge in inverse modelling of the lung - that is, identify mathematical models of lung mechanics that give insight into its structure and may be diagnostic of certain diseases. The complexity of such models, however, is limited by the number of distinct components that can be unambiguously resolved from the measured signals. The development of more detailed models requires the availability of experimental methods for obtaining additional input-output information from the lungs. One such method is the so-called alveolar capsule technique which allows alveolar pressures at several sites on the lung surface to be measured directly. This technique has been used in animals to show that the mechanical behaviour of normal lungs in the breathing frequency range is well described by a homogeneously ventilated compartment surrounded by viscoelastic tissue. During bronchoconstriction, however, the lungs can become markedly inhomogeneous resulting from differences in regional resistive and elastic properties. Model ambiguity problems again appear as it becomes impossible to distinguish changes in local resistance from changes in elastance using only the information obtained from alveolar capsules. To push the inverse modelling of the lung one step further, we have recently developed a new technique for quantifying changes in local resistance and elastance by applying broad-band oscillations in flow to the lung through a small hole in the pleura, thereby obtaining an alveolar input impedance.     

The management of preexcitation syndromes

The introduction of new techniques such as epicardial mapping and programmed stimulation of the heart has made it possible to unravel most of the mysteries surrounding ventricular preexcitation. They helped us to understand the mechanisms of the arrhythmias that frequently are found in these patients and led to better-directed therapeutic interventions. The purpose of this article is to review this information and to indicate how it can be used in the treatment of the patient with preexcitation.     

A three-year prospective study of systemic manifestation in rheumatoid arthritis

Clinical Rheumatology - Rheumatoid arthritis (RA) as a systemic disease can attack many other organs in addition to the joints. A variety of pathological lesions of the blood vessels are...