Activation of Src tyrosine kinase in microglia in the rat hippocampus following transient forebrain ischemia

To better understand the pathophysiological role of Src protein, a non-receptor protein tyrosine kinase of 60kDa, in the ischemic brain, we investigated the time course and regional distribution of active Src expression by using a specific antibody against Tyr416 phosphorylated Src (phospho-Src) in the rat hippocampus after transient forebrain ischemia. In the hippocampus of the control animals, active Src expression was too low to be detected by immunolabeling. Beginning 4h after reperfusion, active Src expression became evident and, after 1 day, had increased preferentially in the CA field of the hippocampus proper and the dentate gyrus. By day 3, active Src expression markedly increased in the pyramidal cell layer of CA1 and the dentate hilar region in temporal correlation with neuronal cell death occurring in these areas, where cells typical of phagocytic microglia showed phospho-Src immunoreactivity. Double-labeling experiments revealed that cells expressing active Src were microglia that stained for biotinylated lectin derived from Griffonia simplicifolia (GSI-B4). Active Src expression began to decline at day 7 and returned to the basal level by day 14 after reperfusion. These results demonstrate increased phosphorylation of Src in activated microglia of the post-ischemic hippocampus, indicating that Src signaling may be involved in the microglial reaction to an ischemic insult.     

PD-1-Expressing SARS-CoV-2-Specific CD8+ T Cells Are Not Exhausted,but Functional in Patients with COVID-19

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Spontaneous programmed cell death of peripheral blood mononuclear cells from HIV-infected persons is decreased with interleukin-15

Interleukin 15 (IL-15) is an important regulatory cytokine in cellular immunity. In vitro replacement of IL-15 has been shown to enhance immunity in Human immunodeficiency virus type 1 (HIV-1) infected lymphocytes. We evaluated the effect of IL-15 on the survival of peripheral blood mononuclear cells of HIV patients by examining in vitro lymphocyte apoptosis, and correlated the process with Bcl-2 and Fas gene regulation. Peripheral blood mononuclear cells (PBMC) from 21 HIV-infected adults and 24 HIV-seronegative healthy individuals were isolated and cultured to determine the effect of escalating doses of IL-15 (0, 1, 10, 100, 1000 ng/mL) on apoptosis. Lymphocyte proliferation assay with (3H) TdR was measured and Bcl-2 and Fas gene regulation was observed. The results were as follows: 1) IL-15 reduced culture induced lymphocyte apoptosis in HIV patients in a dose dependent manner, and reached a plateau level at a concentration of 100 ng/ml; 2) IL-15 significantly reduced the level of apoptosis after 3 days (14%) and 5 days (15%) of culture in HIV patients, while no difference was observed in HIV (-) donors; 3) The percentage of viable cells among the total number of lymphocytes was significantly enhanced by 25% in HIV patients with IL-15; 4) Bcl-2 expression was decreased in HIV patients (53.9 +/- 12.3%) compared to HIV (-) donors (93.0 +/- 3.7%), and IL-15 increased Bcl-2 expression by 21.2 +/- 5.2% in HIV patients; 5) Fas expression was increased in HIV patients (70.2 +/- 4.6%) compared to HIV (-) donors (32.4 +/- 4.3%), and IL-15 increased Fas expression by 8.4 +/- 1.2% in HIV (-) donors. Our findings indicate that IL-15 may influence immunologic abnormalities in HIV infection, particularly its ability to prevent apoptosis of lymphocytes by suppressing the down-modulation of Bcl-2. This may provide an experimental basis for IL-15 immunotherapy.     

Radiologic findings of Mirizzi syndrome with emphasis on MRI

We have reported a case of Mirizzi syndrome preoperatively diagnosed using MR cholangiopancreatography. MRCP and T2-weighted image using a single-shot fast spin-echo sequence accurately depicted all components of Mirizzi syndrome, including impacted stone in the neck of the gallbladder compressing the common hepatic duct and wall-thickening of the gallbladder without any evidence of malignancy. The combination of MRCP and T2-weighted image can be counted on to replace conventional modalities of diagnosing Mirizzi syndrome without any loss of diagnostic accuracy.     

Estrogen affects vascular tone differently according to vasoactive substances in ovariectomized Sprague-Dawley rat

The favorable effects of estrogen on cardiovascular diseases can be explained by several mechanisms such as changes in serum lipid profiles and thrombogenecity. Estrogen also affects the vascular tone, but there has been no report in which the effect of estrogen was tested comprehensively for several vasoactive substances, especially after long-term administration. Two weeks after bilateral ovariectomy in 8-week old female Sprague-Dawley rats, placebo or 17 beta-estradiol (E2) pellets (0.5 mg; released over 3 weeks) were implanted subcutaneously. Two weeks after pellet implantation, organ chamber experiments were performed using aortae. Compared with control, E2-treated vessels showed impaired endothelium-dependent relaxation to acetylcholine. E2 enhanced the contraction to norepinephrine and U46619 and had no effect on endothelin-1-induced contraction. In contrast, the contraction to angiotensin (AT)-II was inhibited by E2. Northern blot analysis for AT1 receptor expression using cultured aortic smooth muscle cells showed no difference between control and E2-treated cells, suggesting that AT1 receptor downregulation is not the likely mechanism. These results suggest that E2 affects the vascular tone variably according to vasoactive substances.     

Caspase-3/CPP32 immunoreactivity and its correlation with frequency of apoptotic bodies in human prostatic carcinomas and benign nodular hyperplasias

AIMS: Apoptosis is mediated by apoptosis-specific genes, certain oncogenes and tumour suppressor genes. Caspase-3, a group of cystein proteases, is involved in the induction of apoptosis and has been considered to correlate with apoptosis. The aim of this study was to determine whether caspase-3 is expressed in prostatic carcinoma and benign prostatic hyperplasia, and correlated with the apoptosis. METHODS AND RESULTS: We studied the apoptotic index and caspase-3 immunoreactivity in 40 cases of benign nodular hyperplasia (BPH) and 40 cases of prostate carcinoma (PCA) by in-situ labelling and immunohistochemistry. The mean number of apoptotic bodies in cases with BPH was not significantly different from cases with PCA I (Gleason score 2-4), but samples from patients with PCA II (Gleason score 5-7) and PCA III (Gleason score 8-10) showed a significantly higher apoptotic number than cases with BPH. Positive staining for caspase-3 was seen in 42.5% (17/40) of the BPH, and 27.5% (11/40) of the PCA: PCA I was 41.7% (5/12), PCA II 14.3% (2/14) and PCA III was 28.6% (4/14). CONCLUSIONS: Based on our results, the number of apoptotic bodies was not correlated with the caspase-3 expression and there was no relationship between caspase-3 expression and Gleason score. However, the number of apoptotic bodies was significantly higher in cases with intermediate (Gleason score 5-7) and high-grade (Gleason score 8-10) PCAs than cases with BPH and low-grade PCAs (Gleason score 2-4).     

Interstitial mononuclear cell infiltrates in chronic rejection of the kidney and correlation with peripheral blood.

To investigate the characteristics of interstitial inflammatory cells and possible involvement of nudelta T cells, 16 renal allograft biopsies showing chronic rejection were stained by immunohistochemical method and correlated with the data of peripheral blood evaluated by flow cytometry. For immunophenotyping, fresh frozen sections were stained with monoclonal antibodies against CD3, CD4, CD8, CD68, CD56, TCRdelta1 and HLA DR. Paraffin embedded tissue was stained with CD45RO, CD20-Cy and CD68. Nine cases of nonspecific tubulointerstitial change and 4 cases of nonallograft tubulointerstitial nephritis were used as a control. Inflammatory infiltration was present in all cases studied. T cells predominated in the interstitium of chronic rejection and were followed by macrophages and B cells. The degree of interstitial infiltration of frozen section was not accordant with that of paraffin sections. Allografts with nonspecific tubulointerstitial changes or tubulointerstitial nephritis of native kidneys showed similar distribution pattern in terms of type and degree. However, the degree of infiltrate did not give any statistical significance among groups. The CD4/CD8 ratios in interstitial infiltrates were less than 1.0 in 6 cases and was not accordant with those of peripheral blood. Proportion of nudelta T cells increased over 10% in 2 cases in tissue and in 3 cases in peripheral blood. In 3 cases of chronic rejection in which both tissue and blood results were available, there was no concordance of CD4/CD8 or nudeltaT/CD3 between them. Tubular expression of HLA DR was, however, present only in 4 cases of chronic rejection. In conclusion, T lymphocytes were predominant regardless of diagnosis or disease activity. T lymphocyte subset did not give any suggestion as to the diagnosis or disease activity in chronic rejection. Furthermore nudelta T cells had only limited value. Lymphocytic subsets in peripheral blood would not be predictors of tissue destruction in chronic rejection.     

Diastematomyelia--clinical manifestation and treatment outcome.

Diastematomyelia is a rare congenital anomaly characterized by a division of the spinal cord or the filum terminale into two parts. In Korea, only one case has been reported. The authors have operated on 5 cases of diastematomyelia with septum since July, 1978. The ages ranged from 1 to 44 years (median; 11 years). There were 2 boys, 2 girls and an adult man. The disease manifested by cutaneous abnormalities and neurological or orthopedic deficits. Pain was a chief complaint in the adult patient. The symptoms had progressed in 3 cases. The diagnosis was made correctly by CT myelography or MRI in 4 cases. The median septum was located at the lumbar area in 4 cases and at the lumbosacral region in 1 case. Associated abnormalities included low lying conus (5 cases), lipoma (2 cases), thickened filum terminale (1 case), hemilipomyelomeningocele (1 case) and syrinx (1 case). The median septum was removed. The dural sleeve adjoining the septum was resected and the dural sac was reconstructed. The role of MRI in the diagnosis and planning of surgery and the high frequency of associated low lying conus were emphasized. Though the surgical treatment relieved pain, it did not reverse the neurological deficits or orthopedic deformities significantly, which suggests the beneficial effects of early surgical intervention in the cases with progressive symptoms.     

Thymocyte-thymocyte interaction for efficient positive selection and maturation of CD4 T cells

Despite numerous reports on MHC class II expression by T cells from a wide spectrum of mammalian species including humans, the biological relevance of this phenomenon has never been tested with appropriately designed animal models. To address this issue, we developed mouse models in which immature thymocytes are the only positively selecting antigen-presenting cells in the thymus. In these mice, CD4+ T cells were generated with the appropriate maturation phenotype and showed a diverse repertoire of TCR Vbetas. The CD4+ T cells were functionally competent, mediating effective allogeneic responses that involved polyclonal TCR Vbetas. These results suggest that the thymocyte-thymocyte (T-T) interaction operates as an independent pathway for CD4+ T cell selection in the thymi of species with MHC II-positive thymocytes. This T-T interaction appears to be the basis for the generation of donor MHC-restricted CD4+ T cells in xenogeneic hosts.