Enhancement of N-methyl- D-aspartate receptor-mediated excitatory postsynaptic potentials in the neostriatum after methamphetamine sensitization. An in vitro slice study

It has been suggested that behavioral methamphetamine sensitization involves changes in cortical excitatory synaptic inputs to neostriatal (Str) projection neurons. To test this, we performed blind whole-cell recording of medium spiny neurons in Str slice preparations. In Str neurons of naive rats, the amplitude of the subcortical white matter stimulation-induced N-methyl- D-aspartate receptor-mediated excitatory postsynaptic potentials (NMDA-EPSPs) was decreased upon hyperpolarization, owing to the voltage-dependent Mg(2+) blockade of NMDA receptor channels. In contrast, the amplitude of the NMDA-EPSPs in Str neurons of rats undergoing methamphetamine withdrawal (MW) did not show the Mg(2+) blockade and was nearly voltage independent over the membrane potential range of -70 to -110 mV. Application of the specific protein kinase C (PKC) activator, phorbol 12, 13- DL-acetate, blocked the voltage-dependent Mg(2+) blockade of NMDA receptor channels in Str neurons of naive rats. Application of the specific activator of cAMP-dependent protein kinase A (PKA), Sp-cAMPS-triethylamine salt, increased the amplitude of the NMDA receptor-mediated EPSPs at the rest but not at hyperpolarized potentials. Coapplication of the PKC and PKA activators yielded NMDA-EPSPs similar to those seen in Str neurons of MW rats. In Str slices of naive rats, tetanic subcortical white matter stimulation induced long-term depression of field potentials. In Str slices treated with the PKC and/or PKA, the same stimulation induced long-term potentiation of field potentials similar to those observed in slices obtained from MW rats. These results suggest that the enhancement of the NMDA receptor-mediated corticostriatal synaptic transmission plays an important role in behavioral methamphetamine sensitization. This enhancement is probably associated with phosphorylation of NMDA receptors mediated by the simultaneous activation of PKC and PKA.     

Chondrosarcomatous differentiation in metastatic deposit of serous papillary cystadenocarcinoma

A rare case of serous papillary cystadenocarcinoma of the ovary showing chondrosarcomatous differentiation in a metastatic deposit late in the clinical course is reported. A 49-year-old female underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy for bilateral ovarian tumors. Histological diagnosis was serous papillary cystadenocarcinoma of both ovaries with lymph node metastasis. After six courses of chemotherapy, she was confirmed to be in complete remission following a second laparotomy. Following additional chemotherapy, a third laparotomy disclosed swollen left inguinal lymph nodes. In one of these nodes, approximately 5.0 cm in greatest diameter, the predominant histological features were: chondrosarcoma of the bone and soft tissue, with small foci of serous papillary adenocarcinoma and squamous epithelium. A histological transition between mesenchymal and epithelial areas was identified. Immunohistochemical positivity for broad-spectrum cytokeratin (AE1/AE3), vimentin, epithelial membrane antigen, and S-100 protein was observed in both chondrosarcomatous and epithelial areas. The current evidence may suggest that the chondrosarcomatous differentiation was derived from the metastatic epithelial component.     

Diagnosis of hepatocellular carcinoma in patients with liver cirrhosis using liver function assays

Sex, age and 21 routine liver function assays were analyzed by stepwise selection and the best-of-all-possible-combinations method to identify a small group of assays valuable in establishing which liver cirrhosis (LC) patients have a high risk of hepatocellular carcinoma (HCC), when alpha-fetoprotein (AFP) is not elevated. Data was obtained from 115 HCC and 122 LC patients on admission. Tumor size correlated with AFP (0.73), alkaline phosphatase (ALP, 0.47), leucine aminopeptidase (LAP, 0.42), lactic dehydrogenase (LDH, 0.42), and the glutamic oxaloacetic transaminase (GOT)/glutamic pyruvic transaminase (GPT) ratio (GOT/GPT, 0.41). The mean of the correct diagnosis rates (CDR) of HCC and LC utilizing AFP as the sole parameter (89%) was markedly higher than those of the other parameters. The best-of-all-possible-combinations method presented a more powerful combination than stepwise selection. The best combination of 7 parameters (LAP, GOT/GPT, choline esterase, one-hour erythrocyte sedimentation rate, age, albumin/globulin ratio, and total bilirubin) presented a mean CDR of 80%, HCC CDR of 77%, and false positive rate of 18%. LC patients statistically diagnosed as having HCC by these 7 parameters are proposed as high risk patients. Fourteen (78%) of 18 HCC patients who were AFP-negative were statistically diagnosed. This analysis can be applied to LC patients to distinguish those that should be followed closely by imaging diagnostic techniques.     

Derivation and morphological characterization of mouse spermatogonial stem cell lines

Spermatogonial stem cells (SSCs), having yet to possess decisive markers, can only be detected retrospectively by transplantation assay. It was reported recently that mouse gonocytes collected from DBA/2 and ICR neonates propagated in vitro. This cultured germ cell, named the germline stem cell (GS cell), produced functional sperm to make progeny when transplanted into recipient mouse testes. Here we show that GS cell lines can be established not only from neonatal testes but also from the testis of adult mice. We also confirmed that GS cells once transplanted into a host testis can be recovered to resume in vitro expansion, indicating that they are convertible mutually with SSCs in adult testes. Confocal laser microscopic examination showed GS cells resemble undifferentiated spermatogonia in the adult testis. This unique cell line could be useful for research in germ cell biology and applicable as a new tool for the genetic engineering of animals.     

Non-MHC driven exacerbation of experimental thyroiditis in the postpartum period

Many human autoimmune diseases, including those of the thyroid gland, are affected by immune changes during pregnancy and the postpartum period. To investigate this influence, we have developed an animal model of pregnancy thyroiditis by using thyroglobulin (Tg)-induced experimental autoimmune thyroiditis (EAT). We now report a study of the post-partum period in mice with EAT. At 5 weeks postpartum, which was 9 weeks after the completion of a Tg immunization regime, the mean thyroiditis grade was significantly increased in the postpartum group from 0.23 to 0.43 (p<0.05) and the thyroiditis Index, which reflected both the frequency and severity of thyroiditis, was similarly increased compared to controls (29.0 vs 9.0). When Tg immunized CBA/J (H-2k) female mice were mated with BALB/c (H-2d) males, there was a similar increase in the severity of thyroiditis in the postpartum period as seen with CBA/J males suggesting that allogeneic factors were not able to further this postpartum exacerbation. Spleen cell IL-4 secretion was enhanced in the postpartum but only in the presence of thyroiditis indicating enhanced activity of Th2 immune responses. There were no differences in IFN-gamma secretion, titers of anti-Tg, CD8+ & CD4+ T cells and T cell chemokine receptor (CCR5, CCR3) expression between non-pregnant control mice with thyroiditis and postpartum thyroiditis. In summary, we found that the severity of EAT during the postpartum was significantly greater than in non-pregnant control mice and was associated with enhanced Th2 immune responses. The allogenicity of the pregnancy had no influence on these findings. The lack of allogenic impact was in contrast to earlier observations in pregnancy itself where an exacerbation of thyroiditis was male strain-dependent and involved primarily Th1 responses. This indicated that the postpartum exacerbation of autoimmune thyroid disease was not a simple response to fetal antigens but secondary to unique postpartum factors.     

Conversion of Salmonella typhimurium to L-forms contributes to the maintenance of acquired immunity against murine typhoid.

Conversion of Salmonella typhimurium to L-forms, both in vitro and in vivo, resulted in the expression of proteins cross-reacting to the mycobacterial 65,000 MW heat-shock protein (hsp). Immunization of C3H/HeJ mice with a protective dose of stable L-form S. typhimurium induced gamma delta T cells in the liver, in accordance with the multiplication of L-form Salmonella in Kupffer cells. The number of gamma delta T cells decreased after the intracellular growth of L-form Salmonella plateaued. Persistance of the L-forms in Kupffer cells, however, allowed hepatic gamma delta T cells to increase within 48 hr of infection with virulent S. typhimurium. Thus, the intrahepatic colonization of L-form Salmonella seems to keep gamma delta T cells on standby, but the emergence of these T cells does not correlate with the expression of L-form hsp. In addition, Kupffer cells colonized by L-forms constitutively synthesized mRNA for interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha). These results suggest that conversion of S. typhimurium to L-forms in phagocytic cells builds up and maintains acquired resistance, conferred by live-cell vaccines of S. typhimurium, against murine typhoid.