Regulation of expression of the ligand for CD40 on T helper lymphocytes

Activated Th cells deliver contact-dependent signals to resting B lymphocytes that initiate and drive B cell proliferation. Recently, a ligand for the B lymphocyte membrane protein, CD40, has been identified that delivers contact-dependent Th cell signals to B cells. A dimeric soluble form of CD40 was produced and used to further characterize the regulation of expression of the CD40 ligand. Expression of the CD40 ligand was rapidly induced after Th lymphocyte activation, and its stability depended upon whether Th cells were activated with soluble or plastic-bound stimuli. Th cells activated with soluble stimuli rapidly turned over cell-surface CD40 ligand whereas Th cells activated with plastic-bound stimuli exhibited more stable CD40 ligand expression for up to 48 h. Removal of activated Th cells from the plastic-bound stimulus resulted in a rapid turnover of CD40 ligand, suggesting that continuous stimulation could maintain CD40 ligand expression. Ligation by soluble CD40 could also stabilize expression of CD40 ligand on the Th cell surface. Both CD40 ligand and IL-2 were transiently synthesized from 1 to 12 h after Th cell activation and had similar kinetics of synthesis. In Con A-activated Th cells newly synthesized CD40 ligand exhibited an initial high turnover (1.5 h t1/2) and after 5 h of Th cell activation became more stable (10-h t1/2). In Th cells activated with plastic-bound anti-CD3, CD40 ligand exhibited a similar biphasic turnover except that the rapid turnover phase began significantly later. This delay could allow more time for newly synthesized CD40 ligand to assemble or associate with other molecules and thus become stabilized on the cell surface. Newly synthesized CD40 ligand in Con A-activated Th cells appeared to not be efficient in delivering Th cell-dependent contact signals to resting B cells, implying the need for assembly or accessory proteins. Regulation of CD40 ligand expression was consistent with all the characteristics of Th cell-delivered contact signals to B cells and may contribute to the high degree of specificity in B cell responses.

Polymorphonuclear leukocytes-mediated lysis of A431 cells induced by IgG1 mouse anti-epidermal growth factor receptor monoclonal antibodies

The ability of different Fc receptors (Fc gamma R) on IgG-mediated cytotoxicity for human epidermoid carcinoma A431 cells bearing large number of epidermal growth factor receptors (EGFRs) was examined by using two isotypes (IgG1 and IgG2a) of murine monoclonal antibodies (MoAbs) against EGFR in the presence of human monocytes and granulocytes. Two MoAbs (225 and LA1) of the IgG1 isotype exhibited effective cytolytic activity for A431 cells with human polymorphonuclear leukocytes (PMN) rather than with human mononuclear cells (MNC). In contrast, two MoAbs (528 and 579) of the IgG2a-isotype lysed the cells less effectively with PMN than with MNC. Anti-Fc gamma R II (CDw32) MoAb 2E1 inhibited the IgG1-mediated cytotoxicity by PMN, and anti-Fc gamma R III (CD16) MoAb 80H3 did not inhibit the IgG2a-mediated cytotoxicity by MNC. Under these conditions, antibody-dependent cell-mediated cytotoxicity by mouse MoAb IgG1 isotypes resulted from antibody binding to the Fc gamma R II (CDw32) of PMN.

Molecular structure and function of the porcine arachidonate 12-lipoxygenase gene

The gene encoding arachidonate 12-lipoxygenase was cloned from a porcine EMBL3 genomic library using a cDNA probe of the enzyme, and its nucleotide sequence was determined. The gene consists of 14 exons with 13 introns, and spans approximately 8 kilobases. Analysis of splice junctions indicated that all of the splice donor and acceptor sites conformed to the GT/AG rule. An approximately 1-kilobase region upstream of the coding sequence contains nine GC-boxes for potential Sp1-binding sites at positions -77, -135, -145, -165, -214, -636, -643, -684, and -813. There are two sets of AP-2 binding sequence at positions -234 and -402. Neither typical TATA box nor CCAAT box is found in this region. The transcriptional start site was determined by primer extension analysis, and was tentatively identified as a cytidine residue located 19 bases upstream from initiation codon. Southern blot analysis revealed the presence of one copy of 12-lipoxygenase gene per haploid genome. We found striking similarities in genomic organization as well as the promoter sequences between the porcine 12-lipoxygenase and the rabbit 15-lipoxygenase genes, suggesting that these genes are evolutionarily related.

[Analysis of scintigrams using fuzzy theory]

Textural features for phantom images were extracted. Texture parameters which represent RI distribution--skew, energy, entropy and angular second moment were used. But, it was difficult to analyse the images using discriminant analysis for textural features, because textural features had statistical noise. Therefore fuzzy reasoning was adapted to analyse the images. Textural features for six kinds of images were showed using membership function. The possibility to the image was evaluated using the value of membership function on each images. Fuzzy reasoning could be done easily using max-min composition formula. The reasoning was found more suitable to analyse the images than discriminant analysis and will be considered useful for analysis of clinical scintigrams.

[99mTc-DMSA renal uptake in urological diseases measured from renal tomographic images using single photon emission computed tomography (SPECT)]

To determine renal function, 99mTc-DMSA renal uptake was measured from renal tomographic images obtained by single photon emission computed tomography (SPECT). A total of 77 tests was conducted on 73 patients with various diseases in the kidneys and urinary tract to determine renal uptake. The correlation coefficient(r) between total renal volume and total renal uptake was 0.3509 and that between renal volume and uptake of 143 kidneys was 0.5433. In 62 patients whose creatinine clearance could be measured, the correlation coefficient between creatinine clearance and total renal volume was 0.2352, and that between creatinine clearance and total renal uptake was 0.8854, that is, creatinine clearance correlated well with renal uptake. Renal volume and uptake determined in 10 normal male and 10 normal female adults were 220 ml and 26.8% for the right kidney and 239 ml and 27.6% for the left kidney for the males and 206 ml and 26.4% (right) and 237 ml and 27.9% (left) for the females. This method, which requires no blood or urine collection, is very useful as an individual kidney function test to evaluate individual kidney function and to understand kidney function before and after operation in patients with renal and urinary diseases.

[A case of distal ureteral atresia]

A case of distal ureteral atresia with the chief complaint of a mass in the left lower quadrant is reported. On palpation of the abdominal region, a 3 X 4 cm mass, smooth-surfaced and movable, was palpable in the left lower quadrant, IVP failed to show the left kidney, while CT revealed an atrophic left kidney and dilated ureter. For the diagnosis of distal ureteral atresia, total left ureteronephrectomy was performed. The left kidney measured 4.5 X 3 X 3 cm and the ureter was dilated and ended blind. The pathohistological findings included dysplasia with normal nephrons here and there of the kidney. We examined the distal ureteral atresia from the renal tissue.

[A case of allergic granulomatous prostatitis]

This is a case report of allergic granulomatous prostatitis and its systemic dissemination. A 45-year-old male visited our hospital with initial symptoms of dysuria, pollakiuria and fever on February 19, 1980. Thereafter, a painless abscess in his left cheek and hard swelling of his right parotid gland appeared. He was hospitalized on March 11 because of hearing difficulties and congestion in the conjunctiva. Physical examination revealed no abnormalities in the chest or abdomen, but a proctological examination showed stone-like hardness of the prostate gland which was the size of a hen's egg. Laboratory findings indicated peripheral eosinophilia and immunoglobulinemia. X-rays showed multiple coin lesions in the chest and multiple cystic changes in the spleen. Biopsies of the cheek lesion and prostate showed eosinophilic granulation accompanied by fibrinoid necrosis and vasculitis. When steroid administration was started, his symptoms and signs showed dramatic but temporary improvement. The allergic lesions then gradually progressed and resisted the steroid therapy. He died on March 13, 1982. In 1972, Towfighi et al. presented 31 cases of nonspecific granulomatous prostatitis with a comprehensive review of the literature. They stated that eosinophilic granulomatous prostatitis with both fibrinoid necrosis and vasculitis caused systemic disease with a poor prognosis. Since the pathological findings in our case showed eosinophilic granulation with fibrinoid necrosis and vasculitis, it was a very rare case of the systemic type of eosinophilic granulomatous prostatitis experienced by Towfighi et al.

Existence and stability of local excitations in homogeneous neural fields

Dynamics of excitation patterns is studied in one-dimensional homogeneous lateral-inhibition type neural fields. The existence of a local excitation pattern solution as well as its waveform stability is proved by the use of the Schauder fixed-point theorem and a generalized version of the Perron-Frobenius theorem of positive matrices to the fuction space. The dynamcis of the field is in general multi-stable so that the field can keep short-term memory.