Pineal melatonin secretion, but not ocular melatonin secretion, is sufficient to maintain normal immune responses in Japanese quail (Coturnix coturnix japonica).

Reports that plasma melatonin is an important immune regulator in avian species have been rather sparse and contradictory. Also, the primary source of immune-modulating melatonin has yet to be determined in birds. In Japanese quail (Coturnix coturnix japonica), the pineal gland and eyes contribute roughly two thirds and one third of the melatonin found in the blood, respectively. Two experiments were conducted to evaluate melatonin as an immune modulator in Japanese quail and to determine the primary source of immune-modulating melatonin in this species. Experiment 1 was designed to evaluate the involvement of the pineal gland and the eyes in immunocompetence. Each of three groups of quail was assigned a surgical treatment and the cellular and humoral immune responses were determined 8 weeks following surgery. The surgical treatments were pinealectomy (Px), sham pinealectomy (SH-Px), and ocular enucleation (eye removal (Ex)). Experiment 2 utilized exogenous melatonin as a replacement to reconstitute immune responses in surgically immunocompromised birds. In this experiment, 50.0 microg/ml of melatonin, or diluent only, was provided to Px and SH-Px birds in the drinking water ad libitum. The cellular and humoral immune responses were determined after 8 weeks of melatonin treatment. In both experiments, a cutaneous basophil hypersensitivity reaction to phytohemagglutinin was measured to evaluate the cellular immune response. To evaluate the humoral immune response, primary antibody titers were determined 7 days postintravenous injection with a Chukar red blood cell suspension. Flow cytometric analysis of peripheral blood lymphocytes was performed to determine the relative percentage of CD4(+) and CD8(+) T- and B-lymphocytes in all treatments of Experiment 2. In Experiment 1, both the SH-Px and Ex surgical treatments produced similar cellular and humoral immune responses, and these responses were significantly greater than those in Px-treated birds. Pinealectomy significantly reduced the cellular and humoral immune responses from SH-Px by 25.8% and 41.3%, respectively. In Experiment 2, Px again resulted in depressed cellular and humoral immune responses. In addition, Px significantly reduced CD8(+) T-lymphocyte numbers compared to SH-Px, while B-lymphocytes remained unchanged. Melatonin administration to Px birds increased the cellular (32.9%) and humoral (30.6%) immune responses to the level of control (SH-Px) birds, although this reconstitution was not due to increased CD8(+) T- or B-lymphocytes. From these data, it was clear that removal of the pineal gland, but not the eyes, reduced cellular and humoral immune responses, which were reconstituted to normal levels by exogenous melatonin. These data suggest that immunodepression is only observed in birds with two thirds of the plasma melatonin removed by pinealectomy. Removal of one third of the plasma melatonin (by ocular enucleation) is not sufficient to reduce cellular and humoral responses in the Japanese quail.

Diagnosis of high-grade pulmonary neuroendocrine carcinoma by fine-needle aspiration biopsy: nonsmall-cell or small-cell type?

A consensus optimal therapy for large-cell neuroendocrine carcinoma of the lung has not been achieved since this entity was proposed in 1991. Accumulation of clinical data and investigation, however, can be greatly impeded by erroneous cytological diagnosis, based on which treatment may be initiated. To avoid erroneous diagnoses, cytological criteria need to be defined. Twenty cases of fine-needle aspiration specimens with a diagnosis of neuroendocrine tumor by either cytology or follow-up histology were retrospectively reviewed for cytomorphologic features. Patients' clinical data were also reviewed. Three cytomorphologic patterns were identified for large-cell neuroendocrine carcinoma, i.e., nonsmall-cell-like, small-cell-like and, mixed nonsmall-cell-small-cell-like. Small-cell-like large-cell neuroendocrine carcinoma can be mistaken for small-cell carcinoma. The most important differential features between these two entities are nuclear size and perceptibility of nucleoli of tumor cells.

Quantitation of lipid-laden macrophages in evaluation of lower airway cytology specimens from pediatric patients.

Quantitation of lipid-laden macrophages has been used as a tool in the diagnosis of aspiration-related respiratory disorders. Fifty-six respiratory specimens from pediatric patients with lung diseases were retrospectively reviewed, and lipid-laden macrophage indices were evaluated according to modified published grading methods. The indices from patients at high risk for aspiration were significantly different from those at low risk. A simpler and more reproducible grading method was introduced. An important issue regarding sample adequacy was also addressed.

Diagnostic value of brush cytology in the diagnosis of duodenal, biliary, and ampullary neoplasms.

Endoscopy is a valuable tool in the diagnosis and management of duodenal lesions and biliary strictures. We assessed the value of cytology in the evaluation of these lesions and analyzed the causes of discrepancy among clinical, histologic, and cytologic parameters. The study included 118 patients with duodenal ulcers, ampullary neoplasms, or biliary strictures who were examined between 1975 and 1995; 120 cytologic examinations were performed. The specimens included brushings of the duodenum (DB, n = 50), ampulla (AB, n = 32), and biliary ducts (BB, n = 38). Endoscopic biopsies performed concurrently included the duodenum (n = 37), the ampulla (n = 22), and the biliary ducts (n = 23). Comparison of cytologic and histologic results showed the following sensitivity and specificity: DB, 40% and 97%, respectively; AB, 100% each; BB, 75% and 93%, respectively. The DB, AB, and BB revealed malignant neoplasms in 2 of 5, 7 of 7, and 6 of 8 cases, respectively. Twenty-three duodenal neoplasms were diagnosed by either modality and included 11 adenocarcinomas, 9 villous tumors, 2 metastatic renal cell carcinomas, and 1 large cell non-Hodgkin's lymphoma. Endoscopic brush cytology is an effective means of diagnosing ampullary neoplasms, and it complements tissue biopsy in cases of bile duct stricture. Location, predominance of tumor-induced stroma, an extramucosal growth pattern, sampling error, and interpretative experience influence the diagnostic evaluation. Cytologic diagnosis of an adenoma does not exclude an underlying malignant neoplasm in ampullary tumors. In some instances, it may be difficult to distinguish between villous tumors with severe dysplasia and adenocarcinomas by cytology alone.