Leishmania donovani: evolution and architecture of the splenic cellular immune response related to control of infection.

Infection with the protozoan Leishmania donovani in humans is usually subclinical. Parasites probably persist for the life of the host and the low-level infection is controlled by the cellular immune response. To better understand the mechanisms related to the control of infection, we studied the evolution and architecture of the splenic cellular immune response in a murine model that is most representative of human subclinical infection. Following systemic inoculation with L. donovani, the parasites were primarily localized to the macrophage-rich splenic red pulp. There was an initial increase in the numbers of T cells and dendritic cells in the periarteriolar lymphoid sheath and marginal zone, but the red pulp (where parasitized macrophages were prominent) remained free of these cells until later in the course of infection. Thus, T cells did not colocalize with parasitized red pulp macrophages until later in the course of infection. Early in the course of infection, IL-10 production within the marginal zone and TGF-beta production by cells in the red pulp were prominent. These macrophage-inhibitory cytokines may contribute to the establishment of the infection and early parasite replication. By day 28 of infection, when the visceral parasite burden began to decline, the number of IL-10-producing spleen cells was back to the baseline level, but IFN-gamma production was higher and the number of IL-12-producing cells was increased dramatically. At this time T cells and dendritic cells had moved out of the lymphoid follicle and marginal zone into the red pulp where the parasites were located. These findings therefore suggest that control of infection is associated with IFN-gamma and IL-12 production and migration of T cells and dendritic cells to the site of chronic parasitism.

Imaging of nonlaryngeal neuroendocrine carcinoma.

The imaging and pathologic features of three cases of nonlaryngeal neuroendocrine carcinoma of the head and neck are described. Neuroendocrine carcinomas represent malignant epithelial neuroendocrine neoplasms and are classified as three types: typical carcinoid (well differentiated), atypical carcinoid (moderately differentiated), and small cell neuroendocrine (poorly differentiated) carcinomas. The CT and MR imaging features of these tumors are nonspecific. Paranasal sinus neuroendocrine carcinomas showed expansion and destruction of the sinus, whereas metastatic neuroendocrine carcinomas to an intraparotid lymph node presented as a circumscribed parotid mass on CT scans.

Free electron laser lithotripsy: threshold radiant exposures.

PURPOSE: To determine the threshold radiant exposures (J/cm2) needed for ablation or fragmentation as a function of infrared wavelengths on various urinary calculi and to determine if there is a relation between these thresholds and lithotripsy efficiencies with respect to optical absorption coefficients. MATERIALS AND METHODS: Human calculi composed of uric acid, calcium oxalate monohydrate (COM), cystine, or magnesium ammonium phosphate hexahydrate (MAPH) were used. The calculi were irradiated in air with the free electron laser (FEL) at six wavelengths: 2.12, 2.5, 2.94, 3.13, 5, and 6.45 microm. RESULTS: Threshold radiant exposures increased as optical absorption decreased. At the near-infrared wave-lengths with low optical absorption, the thresholds were >1.5 J/cm2. The thresholds decreased below 0.5 J/cm2 for regions of high absorption for all the calculus types. Thresholds within the high-absorption regions were statistically different from those in the low-absorption regions, with P values much less than 0.05. CONCLUSIONS: Optical absorption coefficients or threshold radiant exposures can be used to predict lithotripsy efficiencies. For low ablation thresholds, smaller radiant exposures were required to achieve breakdown temperatures or to exceed the dynamic tensile strength of the material. Therefore, more energy is available for fragmentation, resulting in higher lithotripsy efficiencies.

Securing meshed split-thickness skin grafts with 2-octylcyanoacrylate.

Meshed split-thickness skin grafts (STSGs) secured with 2-octylcyanoacrylate (2-OCA) were compared with meshed STSGs secured by suture and bolster (S&B). The 2 techniques were compared for graft survival, foreign-body giant cell response, inflammatory response, appearance, texture, and application time. Sixteen 2.5 x 2. 5 cm meshed STSGs were harvested from the dorsa of 2 pigs for a total of 32 grafts. On each pig 8 grafts were sprayed with 2-OCA, and the other 8 were secured with S&B. Evaluations were performed on postoperative days 14, 24, 48, and 56. Biopsy specimens were obtained on postoperative days 14 and 56. There were no significant differences in percent survival, foreign-body giant cell response, inflammatory response, and appearance between control and study grafts. The average time to apply the 2-OCA onto a graft was 3 seconds, compared with 8 minutes for S&B application. 2-OCA provides a quick and reliable means of securing meshed STSGs and would be especially useful in areas where it is difficult to use S&B, such as total maxillectomy defects.

Leiomyosarcoma of the larynx. Case report.

Leiomyosarcoma involving the larynx is extremely rare and may be difficult to diagnose. Likewise, because of the rarity of this lesion, little information exists with regard to long-term follow-up or optimal management. Reported here is a review of the literature and a case report of a patient with leiomyosarcoma of the larynx treated by surgery alone with 5 years of follow-up.

Bcl-2 family expression in salivary glands from patients with primary Sjögren's syndrome: involvement of Bax in salivary gland destruction.

To investigate the molecular mechanism of glandular parenchyma destruction in Sjögren's syndrome (SS), Bcl-2, Bax, Bcl-X, and Bak expression were studied. SS (n = 18) and control salivary glands (n = 6) were examined by immunohistochemistry. Apoptosis was assessed by in situ DNA nick end labeling. Infiltrating mononuclear cells in the SS salivary gland showed elevated Bcl-2. These mononuclear cells expressed increased Bax but did not undergo apoptosis. Both SS and control salivary gland ductal epithelial cells expressed Bcl-2, Bax, and Bcl-X. SS, but not normal, salivary gland acinar cells expressed Bax and underwent apoptosis. These results suggest that elevated Bax expression in SS salivary gland acinar cells may play an important role in the apoptotic pathway. In contrast, Bcl-2 expression in SS infiltrating mononuclear cells and ductal cells may contribute to their survival.

Fas and Fas ligand expression in the salivary glands of patients with primary Sjögren's syndrome.

OBJECTIVE: To assess the role of Fas-mediated apoptosis in the salivary glands of patients with primary Sjögren's syndrome (SS). METHODS: Expression of Fas, Fas ligand (FasL), and bcl-2 in salivary gland biopsy material was detected in situ by immunohistochemical staining and reverse transcriptase-polymerase chain reaction. DNA fragmentation in apoptotic cells was assessed by the enzymatic incorporation of labeled nucleotides (digoxigenin-dUTP). RESULTS: The acinar epithelial cells in SS were Fas+ and FasL+, and these cells died by apoptosis. The majority of infiltrating lymphocytes in SS were Fas+ and bcl-2+, while few lymphocytes expressed FasL. In situ detection of apoptosis showed minimal cell death of lymphocytes, particularly in dense periductal foci. Lymphocytic cell death was significantly lower (P < 0.0001) in these foci compared with that in the interstitium. CONCLUSION: Infiltrating lymphocytes in the focal lesions of the salivary glands of patients with SS are blocked in their ability to commit to apoptosis, even though they may express Fas. The presence of bcl-2 in these cells may explain their inability to undergo apoptosis. The acinar epithelial cells, in contrast, may undergo Fas-mediated apoptosis. These results suggest that the Fas death pathway may be an important mechanism leading to the glandular destruction found in SS.

Regional odontodysplasia: review of the literature and report of a case.

Regional odontodysplasia is a rare and unique dental developmental anomaly that affects tooth morphogenesis. This case is unusual in that it involved the mandibular dentition. However, in this case the mandible was unilaterally involved. The presence of an abscess in relation to the lower right first permanent molar, in the absence of deep caries or periodontal pathology was an interesting finding. The radiographic appearance of bizarre pulpal morphology with high pulp horns extending to the occlusal surface would provide an open communication between the pulpal tissue and oral cavity. The importance of the first permanent molar as a strategic tooth was recognized and an apexification procedure was performed. The care and treatment of a child with odontodysplasia requires a multidisciplinary approach. In this case the right lower primary cuspid and first primary molar had been extracted previously. The early extraction of these teeth and the subsequent delay in hard tissue formation and eruption of the permanent successors could have resulted in altered growth of the alveolus in this region.

Comparison of N-octyl-cyanoacrylate vs suture in the stabilization of cartilage grafts.

OBJECTIVE: To compare N-octyl-cyanoacrylate and suture control to determine the efficacy of this tissue glue preparation in securing grafted cartilage with an acceptable inflammatory reaction. DESIGN: Four 5-mm circular auricular cartilage grafts were harvested, and 2 of these grafts were either glued together with N-octyl-cyanoacrylate or sewn together with nylon suture. These sandwich grafts were then glued or sewn to the periosteum of the calvaria. Histologic analysis for inflammation, necrosis, fibrosis, and foreign-body giant cell reaction was performed 2 and 6 weeks after implantation. We also measured cartilage graft migration from the original site of surgical implantation. SUBJECTS: Sixteen New Zealand white rabbits. The 2-week study group consisted of 7 rabbits (1 died of dehydration), and the 6-week group totaled 8. INTERVENTION: Each rabbit underwent auricular cartilage harvest and cartilage graft implantation to the parietal skull periosteum. RESULTS: We found no histological differences between the glue specimens and the suture controls. Similarly, our examination of graft migration yielded no differences between groups. CONCLUSIONS: N-octyl-cyanoacrylate was superior to standard suture technique by virtue of its speed, ease, and accuracy of application. No adverse inflammation was observed. Further studies, including clinical trials, are needed to assess the safety of N-octyl-cyanoacrylate in humans.