Electrochemical radiofluorination. Part 2. Anodic monofluorination of substituted benzenes using [18F]fluoride.

Electrochemical fluorination of various monosubstituted aromatic compounds was performed with [18F]fluoride using potentiostatic anodic oxidation on platinum electrodes in an undivided cell in acetonitrile with a mixture of Et(3)N.3HF/Et(3)N.HCl as electrolyte. Maximum radiochemical yields were obtained after a charge of 50C passed the solution. The results showed a clear dependence of the radiochemical yields on the oxidation potentials E(1/2) of the substrates as a consequence of different substituents namely CH(3)CO-, F-, Cl-, Br- and tert.-Butyl. With increasing E(1/2), the fluorination yields decreased from 7.9% (tert.-butylbenzene) to 1.5% (acetophenone). The ratio between F-for-X substitution and F-for-H substitution correlated with the bond energies of the C-X bond. With higher bond energies, less X-substitution was observed.

Impaired up-regulation of CD86 in B cells of "type A" common variable immunodeficiency patients.

Common variable immunodeficiency (CVID) is characterized by defective B cell maturation and antibody formation resulting in low serum antibody levels of most or all Ig isotypes. A specific subgroup of patients ("type A") has normal numbers of mature surface (s)IgM / sIgD- positive circulating B cells. However, since these lymphocytes do not respond to in vitro stimulation by differentiation and Ig synthesis, they seem to suffer from so far unknown intrinsic defects. Analyzing the expression pattern of a large set of B cell activation-specific surface markers, we found that type A CVID patients show a highly reduced expression of the CD28 / CTLA-4 ligand CD86 (B7-2) and of the lymphocyte activation marker CDw137 when compared to B cells of healthy donors and non-type-A CVID patients. The lowered CD86 expression levels were found to correlate with reduced levels of CD86 mRNA. Since combined stimulation via B cell antigen receptor and CD40 cross-linking did not rescue the defects in CD86 and CDw137 expression, B cells of CVID type A patients resemble functionally unresponsive lymphocytes incapable of cooperating with T cells. The fact that these cells accumulate in type A CVID patients suggests a causal relationship with the pathogenesis of this disease.

CD137 (ILA/4-1BB), expressed by primary human monocytes, induces monocyte activation and apoptosis of B lymphocytes.

Human CD137 is a member of the tumor necrosis factor (TNF) receptor family and the homologue of murine 4-1BB. Recent studies have demonstrated that CD137 promotes accessory T cell activation, and regulates proliferation and survival of T lymphocytes. This study reports on the expression and function of CD137 in peripheral blood monocytes. While monocytes showed constitutive expression in 10 out of 18 healthy donors, CD137 was not expressed on resting T or B lymphocytes. Immobilized antibodies to CD137 markedly induced the production of IL-8 and TNF-alpha protein and mRNA, and led to inhibition of IL-10 expression by primary monocytes. Furthermore, cross-linking of CD137 on monocytes resulted in an increase of B lymphocyte apoptosis mediated by direct cell-cell contact of both cell populations. In conclusion, this study identified CD137 as a new receptor involved in monocyte activation by inducing a characteristic cytokine release profile. In addition, CD137 may play a role in monocyte-dependent control of B lymphocyte survival.

Vascular cell adhesion molecule 1 (CD106) on primary human articular chondrocytes: functional regulation of expression by cytokines and comparison with intercellular adhesion molecule 1 (CD54) and very late activation antigen 2.

OBJECTIVE: To investigate the expression of adhesion molecules belonging to the immunoglobulin superfamily on human primary articular chondrocytes and to determine their response pattern to cytokines with respect to the adhesion of lymphocytes. METHODS: The expression of adhesion molecules was studied by flow cytometry (cultured cells), immunohistochemistry (cartilage), reverse transcription-polymerase chain reaction, and Northern blotting. Adhesion of T cells to chondrocytes was measured using the Jurkat T cell line. RESULTS: Vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) were found to be constitutively expressed on large percentages of unstimulated chondrocytes in culture and in cartilage ex vivo. ICAM-2, ICAM-3, and very late activation antigen 4 (VLA-4; alpha4beta1 integrin), the ligand for VCAM-1, were not detected. Interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) further induced VCAM-1 and ICAM-1 messenger RNA and protein expression. Transforming growth factor beta (TGFbeta) had no effect on ICAM-1 and decreased the expression of VCAM-1. Another adhesion molecule, VLA-2 alpha2beta1 integrin) that was also expressed on unstimulated chondrocytes, was differentially regulated by cytokines. While neither IL-1beta nor TNFalpha had any effect on expression of VLA-2, TGFbeta markedly increased the alpha2 subunit of VLA-2. Adhesion of Jurkat T cells to chondrocytes was further induced by IL-1beta and TNFalpha. Pretreatment of chondrocytes with monoclonal antibodies to VCAM-1 and ICAM-1 inhibited adhesion of T cells to chondrocytes. CONCLUSION: VCAM-1, ICAM-1, and VLA-2 are constitutively expressed by human articular chondrocytes. Expression is regulated by cytokines. As shown for other chondrocyte genes, IL-1beta/TNFalpha and TGFbeta antagonistically modulate the expression of adhesion molecules. VCAM-1 and ICAM-1 contribute to adhesion of T lymphocytes to chondrocytes, and may thus participate in host defense mechanisms during inflammatory joint conditions such as rheumatoid arthritis and after cartilage transplantation.

IL-4-deficient Balb/c mice resist infection with Leishmania major.

Mice with a genetically engineered deficiency for either IL-4 or IFN-gamma R1 (single mutants), and IL-4/IFN-gamma R1 (double mutants) on the Balb/c and 129Sv background were used to study the course of infection with Leishmania major. In contrast to genetically resistant 129Sv wildtype mice, IL-4/IFN-gamma R1 double mutant mice developed fetal disease with parasite dissemination to visceral organs similar to mice lacking IFN-gamma R1 only. Balb/c mice, which are exquisitely susceptible to L. major, were rendered resistant to infection by disruption of the IL-4 gene. As compared to homozygous IL-4+/- mice, heterozygous IL-4+/- mice, heterozygous IL-4+/- animals consistently developed smaller lesions with less ulceration and necrosis, indicating the likelihood of gene-dosage effects. This implicates that the magnitude of the IL-4 response determines the severity of disease. CD4+ T cells of IL-4-deficient mice showed impaired Th2 cell development, as assessed by quantitative RT-PCR of characteristic cytokines. Development of resistance is not explained by default Th1 development, because this was observed only at very late stages of infection. Moreover, the induction of inflammatory cytokines (e.g., IL-1 alpha, IL-1 beta, TNF-alpha, IL-12) together with iNOS in the lesion and draining lymph nodes was not altered in the absence of IL-4.

Facial nerve neurinoma presenting as middle cranial fossa mass: CT appearance.

Two cases of large seventh nerve neurinoma presenting as masses in the middle cranial fossa are presented. The radiographic findings are discussed with attention to CT appearance. In the appropriate clinical context, correlation with radiographic studies should strongly support diagnosis of middle fossa neurinoma originating from the seventh cranial nerve. Failure of preoperative diagnosis may result in unexpected operative loss of facial nerve function.

Spontaneous rupture of the spleen in primary plasma cell leukemia. Scintigraphic-pathologic correlation.

A rare case of spontaneous rupture of the spleen occurring in a patient with primary plasma cell leukemia is presented. The scintigraphic-pathologic correlation is presented together with a review of the literature.

A clinical comparison of speed group D and E dental x-ray films.

This study was conducted to determine the clinical diagnostic quality of the new higher-speed Ektaspeed E x-ray films when compared with the diagnostic quality of the lower-speed Ultraspeed D x-ray films. The study also attempted to determine the advantages of 70 versus 90 kVp. The results indicated that the E film at 90 kVp was slightly better than the E film at 70 kVp and the D films at either 70 or 90 kVp. Although the differences were statistically significant, average rating for all films fell within the range of acceptability.

A comparison of rectangular and cylindrical collimation for intraoral radiographs.

This study was conducted to compare the type and frequency of cone-cuts that occur with rectangular and cylindrical collimation in dental radiography. Thirty-eight hundred radiographs, half made with cylindrical cones and half made with rectangular cones, were examined for major and minor cone-cuts. A total of 156 cone-cuts was found. Thirty-three of these were of the major category, 86 percent of which occurred with rectangular collimation. Although cone-cuts appeared much more frequently when a rectangular cone was used, a significant reduction in useless radiation makes this type of collimation a worthwhile consideration.

Pneumothorax in a large autopsy population. A study of 77 cases.

Postmortem chest roentgenograms in approximately 3,500 cases of a random autopsy population were reviewed. Pneumothorax was found in 77 cases (2.2%). Simple pneumothorax was present in 38 cases, and tension pneumothorax or combined simple and tension pneumothorax was present in 39 cases. Only 40 of the 77 patients had been clinically diagnosed as having pneumothorax. Pulmonary conditions most often present in cadavers with pneumothorax were bacterial pneumonia, pulmonary emphysema, and pulmonary embolism, with or without infarcts and infarct abscesses. Procedures most frequently associated with pneumothorax were mechanical ventilation and attempts at cardiorespiratory resuscitation. Rib fractures (iatrogenic and noniatrogenic) were found in 23 of the 77 cases.