Association between frontal sinus development and persistent metopic suture

Background: Frontal sinuses are 2 irregular cavities, placed between 2 lamina of frontal bone. Expansion continues during childhood and reaches full size after puberty. Persistent metopic suture is one of the factors that are related to abnormal frontal sinus development. In this study, we want to discuss about the coexistence of persistent metopic suture and abnormal frontal sinus development using radiological techniques.Materials and methods: In this retrospectively planned study, images of 631 patients were examined, 217 (34.4%) of them were men and 414 (65.6%) of them were women. Brain computed tomography and magnetic resonance images were retrieved from the electronic archive for analysis.Results: In this study, frontal sinus development is categorised as right side atrophy, left side atrophy, bilateral atrophy and bilaterally developed sinuses. The presence of metopic suture was accepted as persistent metopic suture. Frontal sinus atrophy was found in 22.7% and persistent metopic sutures were found in 9.7% of overall.Conclusions: In this study, no significant results were detected that were relatedto the frontal sinus agenesis or dismorphism associated with persistent metopicsuture. We conclude that, although publications propounding metopism thatleads to abnormal frontal sinus development are present in the literature, noreasonable explanation has been mentioned in these articles; and we believe thatthese findings are all incidental.

Hyperreninemic hypoaldosteronism after chronic stress in the rat

The effects of chronic stress on the renin-angiotensin-aldosterone system were studied by analysis of plasma hormone levels, kidney renin mRNA levels, adrenal angiotensin II receptors, and steroidogenesis in rats subjected to repeated immobilization (2 h daily) or intraperitoneal injections of 1.5 M NaCl for 14 d. 24 h after the last stress in both stress models, plasma aldosterone levels were reduced in spite of significant increases in plasma renin activity. Repeatedly intraperitoneal hypertonic saline-injected rats showed plasma renin activity responses to acute immobilization similar to controls, but markedly reduced plasma aldosterone responses. Concomitant with the increases in plasma renin activity, renin mRNA levels in the kidney were significantly increased in intraperitoneal hypertonic saline-injected rats, and these increases were prevented by,B-adrenergic receptor blockade with propranolol. In isolated adrenal glomerulosa cells from chronically stressed rats, maximum aldosterone responses to angiotensin II, ACTH, and 8-Br-cAMP were significantly decreased, whereas pregnenolone responses were increased. P450-aldosterone synthetase mRNA levels and binding of '"I- [Sar',Ile8] angiotensin II were significantly reduced in the adrenal zona glomerulosa of stressed rats. These studies show that chronic repeated stress leads to renin stimulation due to sympathetic activation, and inhibition of aldosterone secretion due to inhibition of the late steroidogenic pathway. The data provide evidence for a role of chronic stress in the development of hyperreninemi

Site-specific immune response to implanted gliomas

Object. Immunotherapy for glioblastoma has been uniformly ineffective. The immunological environment of the brain, with its low expression of major histocompatibility complex (MHC) molecules and limited access for inflammatory cells and humoral immune effectors due to the blood—brain barrier (BBB), may contribute to the failure of immunotherapy. The authors hypothesize that brain tumors are protected from immune surveillance by an intact BBB at early stages of development. To investigate the immunological characteristics of early tumor growth, the authors compared the host response to a glioma implanted into the brain and into subcutaneous tissue. Methods. Samples of tumors growing in the brain or subcutaneously in rats were obtained for 7 consecutive days and were examined immunohistochemically for MHC Class I & II molecules, and for CD4 and CD8 lymphocyte markers. Additionally, B7-1 costimulatory molecule expression and lymphocyte-specific apoptosis were examined. Conclusions. On Days 3 and 4 after implantation, brain tumors displayed significantly lower MHC Class II expression and lymphocytic infiltration (p < 0.05). After Day 5, however, no differences were detected. The MHC Class II expressing cells within the brain tumors appeared to be infiltrating microglia. Minimal B7-1 expression combined with lymphocyte-specific apoptosis were detected in both brain and subcutaneous tumors. Low MHC Class II expression and low lymphocytic infiltration at early time points indicate the importance of the immunologically privileged status of the brain during early tumor growth. These characteristics disappeared at later time points, possibly because the increasing perturbation of the BBB alters the specific immunological environment of the brain. The lack of B7-1 expression combined with lymphocyte apoptosis indicates clonal anergy of glioma-infiltrating lymphocytes regardless of implantation site