Thymic overexpression of CD40 ligand disrupts normal thymic epithelial organization

We characterized the distribution of CD40 and CD40 ligand (CD40-L) in the adult and developing murine thymus. Before birth, CD40 was almost exclusively localized to scattered foci of medullary cells. By birth there was a dramatic upregulation of CD40 expression by cortical epithelial cells, which was accompanied by a consolidation of medullary epithelial foci. CD40-L+ thymocytes displayed a medullary location. Analysis of mice deficient in CD40-L expression indicated that CD40-L/CD40 interactions were not required for development of the medullary compartment. Overexpression of CD40-L targeted to thymocytes altered thymic architecture, as reflected by a dramatic loss of cortical epithelial cells, expansion of the medullary compartment, and extensive infiltration of the capsule with a mixture of CD3+ cells, B-cells, and macrophages/dendritic cells. Reconstitution of lethally irradiated normal mice with lck CD40-L bone marrow cells also resulted in loss of cortical epithelium and expansion of the medullary compartment. Disruption of the normal pattern of thymic architecture and epithelial differentiation as a consequence of increased intrathymic levels of CD40-L expression points to a role for CD40-L/CD40 interactions in the normal pattern of epithelial compartmentalization/differentiation within the thymic environment.     

Obstructed nasolacrimal duct system in epiphora: long-term results of dacryocystoplasty by means of balloon dilation

PURPOSE: To evaluate the long-term results of balloon dacryocystoplasty in the treatment of epiphora due to obstruction of the nasolacrimal ducts. MATERIALS AND METHODS: One hundred eyes in 84 patients with complete or incomplete obstruction of the lacrimal sac and duct were selected for dacryocystoplasty. A catheter with a balloon diameter of 3 mm was used. Follow-up was 5-48 months. No stents were placed. A Kaplan-Meier analysis was used to evaluate patency. RESULTS: The long-term primary patency rate was 70% +/- 7 (+/- standard error). Repeat dacryocystoplasty was successful in 10 of the 11 cases with initial failure or reobstruction during follow-up, which yielded a long-term secondary patency rate of 81% +/- 7. There was no association between the length of the obstruction or the duration of symptoms before dacryocystoplasty and the initial and long-term success. Initial and long-term success was statistically significantly higher in dacryocystoplasty for an incomplete obstruction rather than for a complete obstruction. CONCLUSION: The long-term results of dacryocystoplasty, followed if necessary by repeat dacryocystoplasty, are good. Dacryocystoplasty is a safe and simple procedure and could become the treatment of choice for epiphora due to obstruction of the nasolacrimal ducts. Dacryocystorhinostomy is indicated when dacryocystoplasty or repeat dacryocystoplasty fails or when dacryocystoplasty is contraindicated (e.g., in anatomic malformations in the lacrimal duct or bony canal).     

Differential effects of taxol on two human cancer cell lines

Taxol is the prototype of a new class of drugs with promise in the treatment of various cancers. Its mechanism of action is not fully understood. We have investigated the effects of taxol on two human cancer cell lines, HT-29, derived from a colon carcinoma, and SK-MEL-28, from a melanoma. Immunofluorescence staining for microtubules, cell cycle analysis by flow cytometry, cytotoxicity assays, and DNA fragmentation studies by agarose gel electrophoresis were performed. The two cell lines responded quite differently to taxol. HT-29 cells, when treated with taxol for 24 h, showed an abundance of multiple microtubule asters and the cells were arrested in mitosis. Flow cytometry also showed arrest in mitosis and development of a hypodiploid region with increasing taxol incubation times. These cells were more sensitive to taxol exposure, which caused internucleosomal DNA fragmentation, indicative of apoptosis. The SK-MEL-28 cells, on the other hand, were less sensitive to taxol. Significant cytotoxic effects were only visible after 72 h. These cells exhibited a predominance of microtubule bundles and multinuclei, and only a few cells were arrested in mitosis. Flow cytometry revealed that the SK-MEL-28 cells became polyploid, as a result of exit from mitosis without cell division. These results suggest that the mechanism involved in taxol-induced cell death is different in these two cell lines.     

The value of immunoglobulin and complement levels in the early diagnosis of neonatal sepsis

Serum IgG, IgG1, G2, G3, G4, IgM, C3c and C4 concentrations were measured in 24 term neonates with sepsis and 17 healthy normal neonates of similar age, sex and weight (control group). The serum IgG, IgG1, G2, G3, G4, IgM, C3c, and C4 levels were similar in the patients with sepsis and the control group (p > 0.05). In the neonates with sepsis, serum IgG, G1, G2, IgM and C4 levels were not significantly different between the 1st and 10th days, while there were significant differences for IgG3, G4 and C3c (p < 0.05). We conclude that the serum levels of IgG, IgG1, G2, G3, G4, IgM, C3c and C4 concentrations are of no value for the early diagnosis of neonatal sepsis.     

Pseudopeptide TASP inhibitors of HIV entry bind specifically to a 95-kDa cell surface protein

The template assembled synthetic peptide constructs (TASP), pentavalently presenting the tripeptide KPR or RPK, are potent and specific inhibitors of human immunodeficiency virus (HIV) infection by preventing viral entry into permissive cells. Here the 5[KPsi(CH2N)PR]-TASP construct, Psi(CH2N) for reduced peptide bond, was used in studies to demonstrate its specific binding to a 95-kDa cell surface protein ligand. Compared to its nonreduced 5[KPR]-TASP counterpart, the pseudopeptide 5[KPsi(CH2N)PR]-TASP manifested higher affinity to bind to its cell surface ligand, increased activity to inhibit HIV infection, and resistance to degradation when incubated in serum from an HIV-1 seropositive individual. In ligand blotting experiments, the biotin-labeled 5[KPsi(CH2N)PR]-TASP identified a single 95-kDa protein in crude cell extracts. This 95-kDa protein (p95) is expressed on the cell surface since surface iodination of cells resulted in its labeling, and moreover, following incubation of cells with the biotin-labeled 5[KPsi(CH2N)PR]-TASP, the p95.TASP complex was recovered by affinity chromatography using avidin-agarose. All anti-HIV TASP constructs but not their control derivatives affected the binding of biotin-labeled 5[KPsi(CH2N)PR]-TASP to p95, thus emphasizing the specific nature of this binding. Since 5[KPsi(CH2N)PR]-TASP does not interact with HIV-envelope glycoproteins, our results suggest that TASP inhibitors mediate directly or indirectly a block in HIV-mediated membrane fusion process by binding to the cell surface expressed p95.     

Serum soluble IL-6 receptor concentrations correlate with stages of multiple myeloma defined by serum beta 2-microglobulin and C-reactive protein

Serum soluble interleukin-6 receptor (sIL-6R) concentrations were measured in 52 patients with multiple myeloma (MM) and 24 normal controls, using a commercially available immunoenzymatic assay kit. Patients were staged according to the Bataille et al. myeloma staging system based on the levels of patients' serum beta 2-microglobulin and C-reactive protein. Twenty-one patients were at stage A of disease, 19 at stage B and 12 at stage C at the time of serum collection for sIL-6R determination. Serum sIL-6R concentrations ranged from 15 to 176 ng/ml with a mean of 64.8 +/- 35.9 ng/ml and a median of 58 ng/ml in the entire group of patients studied. These values were significantly higher than those of 34.4 +/- 13.4 ng/ml found in the controls (P < or = 0.001). Patients of stage C had higher sIL-6R levels (94.8 + 41.2 ng/ml) than patients of stage B (67.7 +/- 31.0 ng/ml) (P < 0.01), and markedly higher than patients of stage A (45.0 +/- 23.1 ng/ml) (P < 0.001). Serum levels of sIL-6R in patients with stage A disease did not differ statistically from those of the controls. A linear positive correlation was observed between serum levels of the receptor and the stage of MM (r = 0.539, P < 0.001). These data strongly suggest that serum sIL-6R concentrations correlate with the stages of MM and may be used as an indicator of the activity of the disease.     

Cisplatin resistance is associated with reduced interferon-gamma-sensitivity and increased HER-2 expression in cultured ovarian carcinoma cells

In ovarian carcinoma cells, the combination of interferon-gamma (IFN-gamma) and cisplatin (cDDP) has been reported to result in a synergistic amplification of antiproliferative activity. To assess whether IFN-gamma may also prevent the occurrence of cisplatin resistance, the human ovarian carcinoma cell line HTB-77 was treated repeatedly in an intermittent fashion with either cisplatin alone (HTB-77cDDP) or cisplatin plus IFN-gamma (HTB-77cDDP + IFN). After 8 months of treatment, both new lines (HTB-77cDDP or HTB-77cDDP + IFN) were found to be three times more resistant to cisplatin than the wild-type cells (HTB-77wt). IFN-gamma could not prevent the development of cisplatin resistance. Interestingly, both HTB-77cDDP and HTB-77cDDP + IFN cells were also less IFN-gamma sensitive than the parental line. Both cisplatin-resistant lines expressed p185HER-2 and HER-2 mRNA at a higher concentration than the HTB-77wt cells. IFN-gamma was in all three HTB-77 cell lines able to suppress the HER-2 message and its encoded protein. The expression of IFN-gamma-induced antigens, namely CA-125 and class II antigens of the major histocompatibility complex (HLA-DR), was markedly augmented by IFN-gamma in all three lines, whereby the most prominent effect was seen in HTB-77cDDP and HTB-77cDDP + IFN.