Increased Levels of Soluble Tumour Necrosis Factor Receptor-I (P55) and Decreased IgG1 Reactivities in HIV-1 Patients with Cytomegalovirus Disease

The purpose of the study was to investigate potential associations between tumour necrosis factor (TNF), soluble TNF receptors (sTNF-Rs), immunoglobulin (Ig)G subclasses and development of cytomegalovirus (CMV) disease amongst human immunodeficiency virus (HIV)-1 patients. We enrolled HIV-1 patients with CD4 counts less than 100/μl in a prospective study and followed them over 1 year for development of CMV disease. Concentrations of TNF, sTNF-RI, sTNF-RII and IgG subclass reactivities were measured by ELISA; levels of CMV pp65 antigenaemia were determined as numbers of pp65 expressing cells/100 000 cells and were measured by staining of leucocytes; and HIV-1 RNA loads were measured by polymerase chain reaction (PCR). Eighteen patients studied with CMV disease had higher levels of sTNF-RI than 18 similar patients without CMV disease. Concentrations of sTNF-RI correlated with levels of CMV antigenaemia in blood samples collected before the development of CMV disease. Patients with CMV disease had lower levels of IgG₁ reactivities to CMV than patients without CMV disease. We conclude that increased levels of sTNF-RI and decreased IgG₁ reactivities are associated with an increased risk of development of CMV disease among HIV-1 patients.     

New stand magnifiers do not meet rated levels of performance

A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'_v) rather than equivalent dioptric power (F_m) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use.     

Radiographic manifestations of bronchiolitis obliterans with organizing pneumonia vs usual interstitial pneumonia

The radiographic findings in 24 cases of bronchiolitis obliterans with organizing pneumonia and 16 cases of usual interstitial pneumonia were reviewed and compared. Some cases of bronchiolitis obliterans with organizing pneumonia have been mistaken for usual interstitial pneumonia, although the two diseases have distinct pathologic findings. Clinically, the diseases often have different manifestations. Bronchiolitis obliterans with organizing pneumonia has a better prognosis and often responds well to steroids. This study shows that the radiologic findings of bronchiolitis obliterans include alveolar opacities without lung-volume loss. Patients with usual interstitial pneumonia, however, have bilateral diffuse interstitial opacities with occasional honeycomb changes, and there is loss of lung volume in most patients. These findings suggest that the chest radiograph can aid in distinguishing the two diseases.     

Relation of the pathogenesis of human immunodeficiency virus infection to various strategies for its control

This paper reviews functionally important insights into the pathogenesis of human immunodeficiency virus (HIV) infection. The major sequela of this infection is early and progressive involvement of the immune system, with widespread immune dysfunction. This pathogenetic feature has a major impact on strategies for control of the infection. The immunosuppression caused by the virus leads to higher levels of viral replication and enhanced potential for development or selection of variant viruses, including forms that are more virulent or even drug resistant. Therefore, control of HIV infection and disease may require antiviral agents and CD4 receptor competitors as well as recombinant DNA-derived lymphokines and subunit vaccine immunotherapies. To be successful, such therapies must work to counter infection in monocytes and nonlymphoid cells as well as in T4 lymphocytes. Because many limbs of the immune system are affected by HIV infection, the complexities of this pathogen can be unraveled only by the careful study of immune functions during the disease and of effective interventions to control infection and disease and to restore immune functions.     

Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy

To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice.     

Chaperonin-mediated assembly of wild-type and mutant subunits of human propionyl-CoA carboxylase expressed in Escherichia coli

We developed a bacterial expression system for the human alpha and beta cDNAs of propionyl-CoA carboxylase (PCC). These cDNAs (less the putative mitochondrial matrix targeting presequences) were co-expressed in Escherichia coli on one plasmid vector with each cDNA having its own IPTG-inducible promoter. Only negligible amounts of active PCC were measured despite the presence of both alpha and beta subunits as indicated by Western blot analysis and the almost complete biotinylation of the alpha subunit. Co-expression of this plasmid with a second plasmid vector over-expressing the E. coli chaperonin proteins, groES and groEL, resulted in a several hundred-fold increase in PCC specific activity, to a level comparable with that found in crude human liver extracts. PCC was partially purified on monomeric avidin affinity resin and the presence of both alpha and beta subunits was demonstrated, thereby confirming the assembly of both subunits into an active enzyme. Deficiency of either alpha PCC or beta PCC results in propionic acidemia, an autosomal recessive disorder. We used this expression system to characterize one missense mutation previously described in five Japanese alleles, namely C1283T (Thr428lle) in beta PCC. This mutation, when expressed in E.coli under the same conditions as that of wild-type PCC, had null activity, despite the presence of assembled alpha PCC and beta PCC subunits. This bacterial expression system can be useful for analysis of either alpha PCC or beta PCC mutations. Our findings indicated that the groES and groEL chaperonin proteins were essential for folding and assembly of the human PCC heteromeric subunits.      

Hypersensitivity pneumonitis in rabbits. Modulation of pulmonary inflammation by long-term aerosol challenge with antigen

Immunized rabbits that were aerosol challenged for 2 to 3 wk with pigeon dropping extract, an etiologic agent of hypersensitivity pneumonitis, developed chronic pulmonary inflammation associated with cell-mediated immunity in bronchoalveolar cells. However, prolonged aerosol challenge for 12 wk resulted in the diminution of pulmonary inflammation (modulation) and the loss of demonstrable cell-mediated immunity. This was probably not due to loss of sensitized lymphocytes that mediated pulmonary inflammation. Furthermore, rabbits undergoing modulation when they were challenged with an unrelated antigen were refractory to the development of pulmonary inflammation for at least 9 wk. After this refractory period, animals reimmunized and aerosol challenged with pigeon dropping extract displayed an anamnestic response and produced pulmonary lesions that were strikingly similar to the histopathology of human hypersensitivity pneumonitis.