TNF-induced modulations of phospholipid metabolism in human breast cancer cells

Tumor necrosis factor alpha (TNF) is a cytokine that is cytocidal for certain tumor cells and induces necrotic and apoptotic forms of cell death. Flow cytometry and transmission electron microscopy analysis demonstrated that in human breast cancer cells (MCF7) TNF induces cell cycle arrest in G0+G1/S, accompanied by apoptosis. 31P and 13C NMR spectroscopy was applied to study cellular metabolism of MCF7 cells during TNF-induced signal to apoptosis. Deuterated choline and 2H NMR spectroscopy were utilized to monitor the kinetics of the rate limiting reactions in phosphocholine metabolism. The NMR measurements revealed that immediately after administration of TNF, choline transport was inhibited by 52+/-6%. Later (approximately 15 h), the activity of phosphocholine:cytidine triphosphate cytidylyltransferase, a key enzyme in the biosynthesis of phosphatidylcholine, was enhanced two-fold. These two opposing changes led to a decrease in the level of phosphocholine. Throughout these changes the energetic state of the cells, determined by the level of nucleoside triphosphates and the rate of glucose metabolism via glycolysis, remained constant. The results indicate that TNF specifically modulates the kinetics of membrane-bound enzymes of the rate determining steps in phosphatidylcholine biosynthesis, possibly as part of early events involved in apoptosis.     

Studies on experimental mixed infection of Schistosoma haematobium and Schistosoma mansoni

Swiss Albino mice have been infected with S. haematobium and challenged 4 weeks later with S. mansoni. Parasitological, pathological and ultrastructural studies were done. The results revealed cross mating between the two species. A reduction in S. mansoni worm load, egg count, hepatic granuloma number and size was noticed. The presence of heterologous immunity was suggested.     

The effects of kainic acid in rats with spontaneous recurrent seizures

1. Rats with spontaneous recurrent seizures (SRS) were obtained by injection of kainic acid (KA; 10 mg/kg SC) to drug-naive rats that regularly developed wet-dog shakes followed by complex partial seizures and status epilepticus. Three to five weeks later, the rats with manifest SRS were selected. 2. The SRS rats were challenged with KA (10 mg/kg SC). The seizures induced in SRS rats by KA were similar to SRS regarding their clinical stage and duration (mean duration of seizures: 44 sec and 43 sec, respectively). The frequency of seizures was, however, increased compared with the frequency of SRS in control, vehicle-treated SRS rats (mean frequency of seizures: 12.9 and 0.4 per 3 hr, respectively). The KA-induced seizures in SRS rats differ behaviorally from KA-induced seizures in naive rats-namely, neither wet-dog shakes nor the status epilepticus could be induced. 3. Repeated injection of an equal dose of KA, applied to the SRS rats 1 day after the previous KA challenge, did not induce seizures. The loss of seizure susceptibility to KA was only temporary, as shown after a 7-day drug-free period, when the repeated injection of KA regained its seizure-triggering capacity. 4. The results indicate that reactivity to the seizure-inducing agent kainic acid changes in rats with spontaneous recurrent seizures.     

Testicular Sertoli cell tumor with a heterologous sarcomatous component: immunohistochemical assessment of Sertoli cell differentiation

OBJECTIVE: Immunohistochemical staining is reported to be useful in distinguishing ovarian Sertoli-stromal cell tumors from carcinosarcomas. To assess Sertoli cell differentiation in a rare malignant biphasic testicular tumor, we compared the immunophenotypic profile of the tumor with that of Sertoli cell nodules and adenomas and mullerian carcinosarcomas. DESIGN: Immunohistochemical staining was performed on 6 testes (4 with hyperplastic Sertoli cell nodules, 2 with Sertoli cell adenomas) and 7 carcinosarcomas (6 involving the uterus, 1 involving the uterus and ovary) using primary monoclonal antibodies AE1/AE3, CAM 5.2, CA 19.9, and antibodies directed against epithelial membrane antigen, carcinoembryonic antigen (monoclonal and polyclonal), S100, placental alkaline phosphatase, and inhibin. These staining results were compared with those of the index case. RESULTS: All testes showed positive staining for inhibin and vimentin in the Sertoli cells of the nodules and adenomas. One Sertoli cell nodule showed focal staining with AE1/AE3 and CAM 5.2. Both adenomas showed focal positive staining for S100. All nodules and adenomas were negative for epithelial membrane antigen, monoclonal and polyclonal carcinoembryonic antigen, CA 19.9, and placental alkaline phosphatase. In contrast, the carcinomatous areas of the carcinosarcomas were all negative for inhibin but exhibited positive staining for AE1/AE3, CAM 5.2, and epithelial membrane antigen. The carcinosarcomas showed variable expression of vimentin, S100, carcinoembryonic antigen, CA 19.9, and placental alkaline phosphatase. The epithelial component of the tumor from the index case showed strong diffuse staining for inhibin and vimentin and only very faint focal staining with AE1/AE3 and CAM 5.2. The epithelial component was negative for epithelial membrane antigen, monoclonal and polyclonal carcinoembryonic antigen, S100, CA 19.9, and placental alkaline phosphatase. CONCLUSIONS: The immunohistochemical findings in the index case support the diagnosis of Sertoli cell tumor with a heterologous sarcomatous component over carcinosarcoma. Inhibin seems to be the best single marker for Sertoli cell differentiation. To our knowledge, only 1 other case of this rare testicular tumor has been reported in the literature.     

Autoimmune responses against acetylcholine receptor: T and B cell collaboration and manipulation by synthetic peptides

Myasthenia gravis (MG) and experimental autoimmune MG (EAMG) are induced by antibodies (Abs) against self acetylcholine receptor (AChR). We have mapped the T and B cell epitopes on AChR alpha subunit in human MG and in EAMG-susceptible (C57BL/6, B6) and nonsusceptible mouse strains. A T-cell epitope within residues alpha 146-162 (P14) of Torpedo californica (t)AChR plays an important role in EAMG pathogenesis of the auto Ab-induced disease. P14-specific T cell (P14Th) lines from tAChR-primed B6 mice activated, in vivo and in vitro, tAChR-primed B cells that secreted anti-AChR Abs directed against four other regions on the tAChR alpha-chain, but not against P14 itself. P14Th cells are pathogenic because they help B cells that make Abs against a conserved tAChR region (t alpha 122-150) involved in ACh binding. These Abs cross-react with region alpha 122-150 of mouse (m)AChR, thereby disrupting its normal physiological function. Thus, a T cell epitope not recognized by Abs plays an active role in B cell responses against other epitopes on the protein. We have found that in B6, the MHC region 62-76 of I-A beta(b) is involved in the presentation of P14 to T cells. Anti-peptide Abs, prepared in BALB/c, were found to inhibit in vitro the proliferation of P14-specific T-cells. Furthermore, this MHC peptide elicited Abs in B6 mice and we are investigating whether immunization of B6 with this peptide, before priming with tAChR, would suppress in vivo the T-cell response to the epitope in P14. Thus, these preliminary results would suggest that immunization with the MHC peptide might be employed for control of the autoimmune disease.     

Intrinsic specificity of the reactive site loop of alpha1-antitrypsin, alpha1-antichymotrypsin, antithrombin III, and protease nexin I

Members of the serpin (serine protease inhibitor) family share a similar backbone structure but expose a variable reactive-site loop, which binds to the catalytic groove of the target protease. Specificity originates in part from the sequence of this loop and also from secondary binding sites that contribute to the inhibitor function. To clarify the intrinsic contribution of the reactive-site loop, alpha1-antichymotrypsin has been utilized as a scaffold to construct chimeras carrying the loop of antithrombin III, protease nexin 1, or alpha1-antitrypsin. Reactive-site loops not only vary in sequence but also in length; therefore, the length of the reactive-site loop was also varied in the chimeras. The efficacy of the specificity transfer was evaluated by measuring the stoichiometry of the reaction, the ability to form an SDS-stable complex, and the association rate constant with a number of potential targets (chymotrypsin, neutrophil elastase, trypsin, thrombin, factor Xa, activated protein C, and urokinase). Overall, substitution of a reactive-site loop was not sufficient to transfer the specificity of a given serpin to alpha1-antichymotrypsin. Specificity of the chimera partly matched that of the loop donor and partly that of the acceptor, whereas the behavior as an inhibitor or a substrate depended upon the targeted protease. Results suggest that, aside from the contributions of the loop sequence and the framework-specific secondary binding sites, an intramolecular control may be essential for productive interaction.     

Criterion validity of the Center for Epidemiologic Studies Depression scale (CES-D): results from a community-based sample of older subjects in The Netherlands

The Center for Epidemiologic Studies Depression scale (CES-D) has been widely used in studies of late-life depression. Psychometric properties are generally favourable, but data on the criterion validity of the CES-D in elderly community-based samples are lacking. In a sample of older (55-85 years) inhabitants of the Netherlands, 487 subjects were selected to study criterion validity of the CES-D. Using the 1-month prevalence of major depression derived from the Diagnostic Interview Schedule (DIS) as criterion, the weighted sensitivity of the CES-D was 100%; specificity 88%; and positive predictive value 13.2%. False positives were not more likely among elderly with physical illness, cognitive decline or anxiety. We conclude that the criterion validity of the CES-D for major depression was very satisfactory in this sample of older adults.     

Chronic childhood illness and maternal mental health--why should we care?

This study evaluated which factors most influenced the impact of childhood asthma on the child's family. Seventy children/families seen at a tertiary-care hospital for asthma were evaluated. Stepwise multiple regression examined the effects of illness severity; family socioeconomic status (SES); family structure; social support; child's emotional characteristics; parent's health; family functioning; and maternal psychological distress on the Family Impact of Illness Scale. Analysis indicated that only the parent's Psychiatric Symptom Index significantly predicted impact scores. The most important predictors of how much impact a child's asthma has on the family are parental emotional distress and amount of social support.     

Genetic association between atopy and behavioral symptoms in middle childhood

The relationship of atopic and behavioral symptoms in a community sample of 66 monozygotic and 141 dizygotic twin pairs, ages 4-11 years, was investigated via mother report questionnaires. Within-person correlation between atopic symptoms and Child Behavior Checklist internalizing symptoms (CBCL-INT) was .21 (p < .001) for the total sample. Cross-correlations between atopy and CBCL-INT were .26 for monozygotic and .04 for dizygotic twins. A common and specific factor model applied to the data revealed that the cross-correlation between atopy and CBCL-INT was mainly due to genetic influences (77% of the covariance). This study supports the hypothesis that there is a shared genetic risk for atopy and internalizing symptoms.     

Attaching and effacing enteropathogenic Escherichia coli O18ab invades epithelial cells and causes persistent diarrhea

A case of persistent diarrhea following Escherichia coli O18ab gastroenteritis is reported. Electron microscopy of a biopsy of the small intestine showed effacement of the brush border, attachment of bacteria to the epithelial cells with pedestal formation, and bacteria within the enterocytes. The bacterial isolate was an enteropathogenic E. coli isolate which did not contain the adherence factor (EAF) but possessed the attaching-effacing eae gene, was able to invade HeLa cells in a gentamicin invasion assay, and also invaded rabbit intestinal cells. Results suggest that E. coli organisms of the O18ab serotype may cause diarrhea by an as yet unknown pathogenic mechanism, involving attaching to and effacing of enterocytes followed by invasion of the epithelial cells.