Stimulation of thymocytes before and after positive selection results in the induction of different NF-kappa B/Rel protein complexes

Positive selection triggers the differentiation of immature CD4+8+TCRlow thymocytes into TCRhigh single-positive CD4+ or CD8+ cells and is associated with major changes in gene expression. However, little is known about the DNA binding factors controlling these fundamental changes. Here we have examined NF-kappa B/Rel subunit expression and DNA-binding activity in developing thymocytes before and after the induction of positive selection. We show that positive selection is accompanied by the strong up-regulation of c-rel mRNA expression and the constitutive activation of p50/p65 and p50/c-Rel NF-kappa B/Rel complexes, confirming the activation-like status of cells undergoing positive selection. Moreover, CD69+ cells that have initiated positive selection (but not their preselection CD4+8+TCR- precursors) respond to stimulation by the preferential activation of c-Rel-containing DNA-binding complexes. Because the different NF-kappa B/Rel dimers have distinct transcriptional activities and binding site preferences, this preferential activation of c-Rel-containing DNA-binding complexes may well have implications for the changes in gene expression and functional response associated with positive selection.

Stimulation of thymocytes before and after positive selection results in the induction of different NF-kappa B/Rel protein complexes

Positive selection triggers the differentiation of immature CD4+8+TCRlow thymocytes into TCRhigh single-positive CD4+ or CD8+ cells and is associated with major changes in gene expression. However, little is known about the DNA binding factors controlling these fundamental changes. Here we have examined NF-kappa B/Rel subunit expression and DNA-binding activity in developing thymocytes before and after the induction of positive selection. We show that positive selection is accompanied by the strong up-regulation of c-rel mRNA expression and the constitutive activation of p50/p65 and p50/c-Rel NF-kappa B/Rel complexes, confirming the activation-like status of cells undergoing positive selection. Moreover, CD69+ cells that have initiated positive selection (but not their preselection CD4+8+TCR- precursors) respond to stimulation by the preferential activation of c-Rel-containing DNA-binding complexes. Because the different NF-kappa B/Rel dimers have distinct transcriptional activities and binding site preferences, this preferential activation of c-Rel-containing DNA-binding complexes may well have implications for the changes in gene expression and functional response associated with positive selection.

Induction of thrombosis in a mouse model by IgG, IgM and IgA immunoglobulins from patients with the antiphospholipid syndrome

Antiphospholipid syndrome is a disorder of recurrent thrombosis and pregnancy losses associated with production of anticardiolipin antibodies and lupus anticoagulant positivity. Recently, we have adapted a mouse model of induced venous thrombosis to study the role of autoantibodies in thrombus formation. To determine whether immunoglobulins from patients with the antiphospholipid syndrome play a role in thrombosis, we injected groups of CDI mice either with immunoglobulins purified from seven patients with the antiphospholipid syndrome (nine preparations studied: four IgG, three IgM and two IgA) or with immunoglobulins of the same isotype from healthy controls. Seventy-two h after injection, a non-occlusive thrombus was induced in the femoral veins of experimental mice by a pinch injury; the thrombus areas as well as times of formation and disappearance of the thrombi were measured. Eight of the nine antiphospholipid syndrome immunoglobulin preparations caused a significant increase in mean thrombus area and a significant delay in mean thrombus disappearance time as compared with normal controls. To determine whether anticardiolipin antibodies might be involved, separate groups of mice were injected with affinity-purified IgG (n = 2) or IgM (n = 2) anticardiolipin antibodies or with normal immunoglobulins of the same isotype, and the effects on thrombus formation compared. Mean thrombus area and mean disappearance times were again significantly increased in all four groups injected with affinity-purified antibodies. This is the first study to show that anticardiolipin antibodies of IgG, IgM and IgA isotypes may play a role in thrombosis in vivo.

A decrease from 8 to 6 weeks in obstetrics and gynecology clerkship: effect on medical students' cognitive knowledge

We undertook this study to determine whether a decrease in the amount of time a third-year medical student spent in an obstetrics and gynecology clerkship would cause a decrease in the knowledge of the subject. We compared National Board of Medical Examiners (NBME) obstetrics and gynecology subject examination scores of 168 students at the University of Texas Medical Branch at Galveston completing an 8-week obstetrics and gynecology rotation or the 1989-1990 academic year to scores of 187 University of Texas Medical Branch students competing a 6-week rotation during 1990-1991. No significant change in the total mean NBME subject examination score in obstetrics and gynecology was noted after the decrease in rotation length. Passing scores were those greater than 445 points. The failure rate for those students who completed the 8-week rotation was consistent throughout the 1989-1990 academic year. In contrast, those students who rotated through obstetrics and gynecology during the 6-week clerkship in the first half of the academic year had a failure rate that was statistically higher than those taking the clerkship in the last half of the year. The length of the obstetrics and gynecology clerkship was shortened to 6 weeks without significantly affecting students' overall performance on the NBME obstetrics and gynecology subject examination. However, a greater percentage of students who completed the rotation during the first half of the year scored low on the NBME obstetrics and gynecology subject examination than did those taking the rotation and thus the NBME subject examination in the second half of the year.

Community organization to promote breast cancer screening among women ages 50-75

BACKGROUND

To reduce breast cancer mortality, ways to promote the use of mammography screening among women age 50 and above are needed. Community organization may be a useful approach.

METHODS

The Washington State Community Breast Cancer Screening Project involved implementation of promotional activities initiated by physician and lay community boards in two communities. Two comparable communities served as controls for evaluation purposes. Random-digit-dial telephone interviews were used to assess recent use of mammography at baseline and follow-up in independent samples of women ages 50 to 75 from the four communities. The extent of exposure to intervention activities and the relationship between exposure to intervention activities and mammography use were estimated from data collected at follow-up.

RESULTS

Exposure to patient reminders from physicians, wallet reminder cards, and newspaper advertisements were consistently related to mammography use. Physician office staff encouragement and a display board were significantly related to mammography use only in Intervention Communities A and B, respectively. Neither exposure to promotional activities nor the change in prevalence of mammography use was significantly higher in the intervention communities than in the comparison communities at follow-up.

CONCLUSIONS

Although several activities were useful in promoting mammography use, organization of the community did not enhance efforts undertaken spontaneously by comparable communities.

A peptide from the caudal neurosecretory system of the dogfish Scyliorhinus canicula that is structurally related to urotensin I

Using reversed-phase HPLC in combination with a radioimmunoassay for ovine corticotropin-releasing hormone (CRH), a peptide with CRH-like immunoreactivity was isolated in pure form from an extract of the caudal spinal cord region of the spotted dogfish, Scyliorhinus canicula. The primary structure of the peptide was established as Pro-Ala-Glu-Thr-Pro-Asn-Ser-Leu10-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg- Glu-Met-Ile- Glu20-Ile-Ala-Lys-His-Glu-Asn-Gln-Gln-Met-Gln30-Ala-Asp-Ser- Asn-Arg-Arg-Ile-Met - Asp-Thr40-Ile.NH2. This amino acid sequence shows moderate structural similarity to Catostomus urotensin I (51%) and to human CRH (56%). The data provide, therefore, chemical evidence to support the conclusions of earlier immunohistochemical studies that the diffuse caudal neurosecretory system of elasmobranchs produces a peptide that is immunochemically related to teleost urotensin I peptides. However, the primary structure of urotensin I has been poorly conserved during evolution.

A retrospective analysis of the long-term effect of splenectomy on late infections, graft-versus-host disease, relapse, and survival after allogeneic marrow transplantation for chronic myelogenous leukemia

The present study was performed as a retrospective analysis of the role of pretransplant splenectomy to determine the incidence of late bacterial infections, acute and chronic graft-versus-host disease (GVHD), relapse, and survival among 358 patients receiving HLA-identical marrow grafts for chronic myelogenous leukemia. Sixty-eight (19%) of the 358 patients had undergone splenectomy before transplantation. There was a trend towards more grade II-IV acute GVHD among splenectomized patients, but this was not significant in the multivariate analysis. The incidence of chronic GVHD was similar for splenectomized and nonsplenectomized patients. Late infectious complications did not significantly differ between splenectomized and control patients (rates per patient year were 0.16 and 0.14, respectively). The overall risk of leukemic relapse was significantly increased for splenectomized patients (56% v 32% for controls, P = .001) and control patients with splenomegaly (P < .0001). Splenectomy and splenomegaly remained significant and independent hazards for relapse in the multivariate analysis (hazard ratio [HR], 1.82, P = .029; and HR, 1.49, P = .002; respectively). Relapse was also increased in patients with advanced disease (HR, 2.95; P = .0001), in patients with T-cell-depleted marrow (HR, 4.51; P = .0001), and in the female donor and male recipient combination (HR, 1.74; P = .044). Patients with splenectomy had an increased overall mortality (HR, 1.18), but this was not statistically significant in the multivariate analysis. In summary, our study showed no significant influence of splenectomy on late posttransplant infections, acute or chronic GVHD, or overall survival. There was no evidence that splenectomy decreased recurrence of chronic myelogenous leukemia.

Correlation of cell surface fluorescence with conventional PAP analysis of cells of cytological interest obtained from cervical scrapes

Archival PAP stained cervical smears were destained and treated with a fluorescent probe for a cell surface enzyme (GB). Cells which exhibited cell surface fluorescence were demonstrated to be cells of cytological interest in the analysis of cervical smears. These cells could be directly related to PAP and reclassified by subsequent restaining with PAP. Fluorescent cell surface technology was shown to be compatible with conventional PAP staining.

The role of the thymus during T-lymphocyte development in vitro

To date, fetal thymic organ culture is the only in-vitro system capable of supporting a complete programme of T-lymphocyte development in a manner comparable to that seen in vivo. In this review, we will summarise recent studies in which thymic organ cultures have been used to investigate the regulatory mechanisms of particular stages of thymocyte development. In addition, the use of other culture systems of T-cell maturation will be discussed in an attempt to define the optimal conditions for T-cell development in vitro.

Exfoliative cytology and electron microscopy in the diagnosis of hairy leukoplakia

The diagnosis of lesions clinically suggestive of hairy leukoplakia was assessed by light and electron microscopic examination of cytologic smears. We found exfoliative cytology to be a simple and noninvasive technique that can confirm the clinical diagnosis of hairy leukoplakia. Our results suggest that electron microscopy may be more sensitive and reliable than light microscopy in confirming the clinical diagnosis of hairy leukoplakia.

Intracellular signaling events during positive and negative selection of CD4+CD8+ thymocytes in vitro

We have used in vitro models of thymocyte positive and negative selection in conjunction with selective inhibitors of the TCR-mediated signaling cascade to investigate the intracellular signaling events that mediate these processes. We report that Ro 31.8425, a potent and selective inhibitor of protein kinase C, which blocks the activation of mature T cells in a dose-dependent fashion, has no effect on either positive or negative selection of CD4+8+ thymocytes. In contrast, cyclosporin A fails to prevent negative selection, but inhibits positive selection through a direct effect on developing thymocytes, rather than through the perturbation of stromal cell support. Thus, our data suggest that positive and negative selection may operate via distinct intracellular signaling pathways.

Intracellular signaling events during positive and negative selection of CD4+CD8+ thymocytes in vitro

We have used in vitro models of thymocyte positive and negative selection in conjunction with selective inhibitors of the TCR-mediated signaling cascade to investigate the intracellular signaling events that mediate these processes. We report that Ro 31.8425, a potent and selective inhibitor of protein kinase C, which blocks the activation of mature T cells in a dose-dependent fashion, has no effect on either positive or negative selection of CD4+8+ thymocytes. In contrast, cyclosporin A fails to prevent negative selection, but inhibits positive selection through a direct effect on developing thymocytes, rather than through the perturbation of stromal cell support. Thus, our data suggest that positive and negative selection may operate via distinct intracellular signaling pathways.

Arteriole constriction following ischemia in denervated skeletal muscle

Arteriolar diameters and flow patterns were determined in the isolated rat cremaster muscle following 4 hr of total ischemia. Two groups of six rats each were studied--an innervated group and a denervated group. The microcirculation was observed using intravital microscopy, and the images were recorded on videotape. The whole arterial tree was scanned, and the smallest vessel diameter for each arterial segment was measured. Preischemic mean arteriole diameters were significantly larger in the denervated group, compared to the innervated group. Following ischemia, during the 3 hr of reperfusion, the main (AI) cremaster arteriole from both the innervated and denervated groups constricted to 50 to 70 percent of pre-ischemic diameters. However, the actual diameters (as distinct from percentage change) were not significantly different between the innervated and denervated groups. There were significant differences in flow patterns. Some A2 and A3 vessels became temporarily nonflowing vessels (either open but without low, or closed by severe spasm). These poorly-functioning vessels were significantly more common in the denervated group. Furthermore, this phenomenon of temporary no-flow persisted longer in the denervated group over the 3-hr reperfusion period. These observations suggest that the ability to recover quickly from an ischemic insult is less in tissues that have been denervated.

Linkage between brain serotonin concentration and the sex-specific part of the Y-chromosome in mice

The implication of the sex-specific part of the Y-chromosome (YS-SP) on brain serotonin (5-HT) level was investigated using congenic strains for this chromosomal region. The 5-HT level, which was higher in the NZB than in the CBA/H strain of mice, was depleted by the transfer of the YS-SP from NZB on CBA/H whereas the transfer of the YS-SP from CBA/H on NZB had no effect. The variations of 5-HT levels were not correlated with plasma testosterone concentration which is also dependent of the YS-SP.

Characteristics of an in vitro system of thymocyte positive selection

We investigated the phenotypic changes accompanying maturation of CD4+CD8+ thymocytes in the presence of thymic stomal cells in vitro. Many of the features that are characteristic of positive selection in vivo, such as an ordered down-regulation of CD4 or CD8 together with up-regulation of the TCR-alpha beta complex, also occurred in vitro. Transient expression of CD69 was also observed, together with activation of IL-2 and IL-4 cytokine genes, providing further evidence that positive selection in vitro involves a pattern of gene regulation comparable to that seen in vivo.

Effect of freezing on the in vivo recovery of irradiated red cells

BACKGROUND

Transfusion-associated graft-versus-host disease can be prevented by gamma radiation of blood components. The increased use of blood components donated for patients by their family members has resulted in an increased demand for the storage and handling of irradiated units, and the ability to freeze the cells would allow storage beyond their current expiration date.

STUDY DESIGN AND METHODS

To assess the effect of freezing and deglycerolization on irradiated red cells, studies of autologous radiolabeled red cell recovery were performed using normal volunteers. Each unit of CPDA-1 red cells was immediately divided into two equal volumes. Further handling of each half was identical except that one was irradiated (3500 cGy). The units were grouped under three protocols: I, irradiated on Day 0 and frozen on Day 5 (n = 4); II, irradiated on Day 7, rejuvenated, and frozen on Day 14 (n = 5); and III, irradiated on Day 14, rejuvenated, and frozen on Day 18 (n = 3). All cells were frozen for 3 to 10 months at -80 degrees C.

RESULTS

Irradiated and control units showed no significant differences in supernatant potassium or hemoglobin. Autologous 24-hour posttransfusion recoveries (mean +/- SD) for the three groups were: I, 89.7 +/- 5.6 percent (control, 90.6 +/- 3.2%); II, 85.3 +/- 5.7 percent (control, 83.7 +/- 3.0%); and III, 79.5 +/- 1.4 percent (control, 82.6 +/- 5.2%).

CONCLUSION

Irradiated red cells can be frozen after being stored under various conditions and can still meet established guidelines requiring 75-percent recovery 24 hours after transfusion.

Maxillary adenoid cystic carcinoma with annulate lamellae

Of 29 reviewed ultrastructural studies of adenoid cystic carcinoma, only 1 mentions the presence of annulate lamellae. The present report describes a 65-year-old woman who presented with an adenoid cystic carcinoma in her left maxillary sinus. At the light microscopic level, most of the connective tissue was loose and myxomatous and contained fine strands, cords, and islands of epithelium that in places had a cribriform pattern. The ultrastructural appearance was similar to that described by others. Two epithelial cell types predominated. The cytoplasm of one type contained mainly ribosomes, and that of the other type also had peripheral microfilaments. Also present were pseudocysts, lumina with microvilli, and replicated basal lamina. In addition, a number of both types of cells contained parallel arrays of cisternae that had regular small pores. These were annulate lamellae.

Characteristics of an in vitro system of thymocyte positive selection

We investigated the phenotypic changes accompanying maturation of CD4+CD8+ thymocytes in the presence of thymic stomal cells in vitro. Many of the features that are characteristic of positive selection in vivo, such as an ordered down-regulation of CD4 or CD8 together with up-regulation of the TCR-alpha beta complex, also occurred in vitro. Transient expression of CD69 was also observed, together with activation of IL-2 and IL-4 cytokine genes, providing further evidence that positive selection in vitro involves a pattern of gene regulation comparable to that seen in vivo.

Enhanced stress responsivity of Tourette syndrome patients undergoing lumbar puncture

Tourette's syndrome (TS) is a complex inherited neuropsychiatric disorder that is characterized by multiple motor and phonic tics. Stress-related fluctuations in symptom severity and medication responsiveness are common, and patients often report that tics are worsened by fatigue, emotional trauma, and anxiety. We examined the effects of lumbar puncture (LP) stress on plasma adrenocorticotropin (ACTH) and cortisol, urinary catecholamines, and self- and clinician ratings of anxiety in 13 medication-free TS patients and 10 normal controls, ages 17 to 41 years. The TS patients secreted significantly more ACTH than the normal controls in response to the stress of the lumbar puncture. Compared to the controls the TS patients had significantly greater postLP mean and postLP peak ACTH levels. The TS patients also excreted significantly more norepinephrine in the 20 hr preceding the lumbar puncture and reported higher levels of anxiety before and during the procedure than the controls. In addition, urinary norepinephrine excretion of the TS patients was significantly correlated with clinician ratings of tic severity. The results were not related to current levels of depression and anxiety. Taken together, these findings suggest that a subset of TS patients may be characterized by heightened reactivity of the hypothalamic-pituitary-adrenal axis and related noradrenergic sympathetic systems.