Ultrastructural morphometry distinguishes Burkitt's-like lymphomas from neuroendocrine neoplasms: useful criteria applied to the evaluation of a poorly differentiated neuroendocrine neoplasm of the nasal cavity masquerading as Burkitt's-like lymphoma

The present study describes the potential usefulness of ultrastructural morphometry in diagnosis. Ultrastructural morphometric criteria were applied to the evaluation of a poorly differentiated neuroendocrine neoplasm of the nasal cavity that was initially thought to be a Burkitt's-like lymphoma (BLL). Although the nasal lesion in question failed to stain with over 50 cell lineage-relevant antibodies, it did stain for vimentin (an intermediate filament protein) and Ki-67 (a nuclear antigen associated with cell proliferation). Routine electron microscopy revealed a primitive neoplasm with abundant cytoplasmic lipid droplets and sparse dense granules with no intercellular junctions. Treatment options, which included extensive facial surgery, prompted more study. Tissue processed for the uranaffin reaction revealed sparse uranaffin-positive granules indicating the presence of true neurosecretory granules. An ultrastructural morphometric analysis of the neoplastic nuclei of this patient placed the tumor outside the morphometric domains for BLLs (18 cases) and neuroblastomas (11 cases) and within the morphometric domain of neuroendocrine carcinomas (9 cases). A greater mean standard deviation (P less than 0.05) and mean coefficient of variation (P less than 0.02) of nuclear perimeter in the neuroendocrine (NE) group related to the BLL group indicated greater nuclear pleomorphism within the NE group as illustrated in bivariate graphic displays. The possible origin of the neoplasm within the nasal mucosa is discussed.     

Structure-activity relationship studies of CNS agents. Part 29. N-Methylpiperazino-substituted derivatives of quinazoline, phthalazine and quinoline as novel α1, 5-HT1A and 5-HT2A receptor ligands

New N-methylpiperazino-substituted quinazolines 8 and 9, phthalazine 13, and quinoline 19 have been synthesized. The receptor binding profiles (α₁, 5-HT_1A, 5-HT_2A) of these compounds and their analogs (7–22) have been determined. It has been demonstrated that orientation of a local dipole moment of the heteroaromatic ring system affects both the α₁ and 5-HT_2A affinity of the investigated class of ligands. Distortion of the coplanar unfused heteroaromatic ring system results in a decreased 5-HT_2A affinity. 4-(4-Methylpiperazino)-2-(2-thienyl)quinoline 18 is the most active and selective α₁ ligand (K_i = 4.9 nM) with a much lower affinity for 5-HT_1A (K_i = 3420 nM) and 5-HT_2A (K_i = 211 nM) receptors.     

Use and limitations of light microscopy for diagnosing malaria at the primary health care level

Recent developments in diagnostic techniques for malaria, particularly DNA probes and sero-immunology, have raised questions as to how these techniques might be used to facilitate malaria diagnosis at the most peripheral levels of the primary health care system. At present, malaria diagnosis is based on the light microscope and is likely to remain so in the immediate future. This article describes how the diagnosis of malaria by light microscopy has been improved over the years, and expresses the need for further improvement while concomitant research into other standardized and simplified techniques for the diagnosis of malaria is vigorously pursued.     

Sequential changes in the numbers of B and T lymphocytes and other leukocytes in the blood in Marek's disease

Numbers of B, T and total lymphocytes, monocytes, heterophils, eosinophils and basophils have been examined in the peripheral blood of chickens between 2 and 42 days after infection with Marek's disease virus. During the stage of the acute restrictively productive virus infection of lymphoid tissues at 2–9 days after infection, absolute numbers of B cells, T cells, total lymphocytes and heterophils were increased, those of monocytes and eosinophils were decreased, and those of basophils were unchanged. The lymphoproliferative phase of the disease, from 21–42 days after infection leading to lymphoma formation, was accompanied by an increase in T cells, total lymphocytes and possibly eosinophils, and a decrease in B cells, monocytes, heterophils and basophils. The T-cell increase following infection occurred only in female birds, and there were more lymphomas in females than in males. The increase in lymphocytes in the blood of six birds with leukemia was mainly due to an increase in T cells, but in one bird B cells were also increased. Blast cells and atypical lymphoid cells were increased in leukemic birds. Regression coefficients were calculated between different pairs of leukocytes in infected and uninfected birds at different stages of the disease. Particularly noteworthy were the associations between B and T cell numbers, which indicated constant proportions of these cells irrespective of total numbers, possibly due to a common control mechanism.     

Role of iron in disseminated gonococcal infections.

Strains of Neisseria gonorrhoeae isolated from disseminated gonococcal infections have enhanced ability to acquire iron in an experimental host when compared with urogenital gonococcal isolates from patients with uncomplicated infections.     

Consequences of visual deprivation in the absence of binocular competitive mechanisms in Siamese cat area 17

The Siamese cat is a mutant with abnormally crossed visual pathways, which provides a model for studying the effects of visual deprivation in the absence of binocular competitive interactions. Siamese cats are known to be resistant to the effects of monocular eyelid suture. To further explore the nature of this resistance, the receptive field properties of neurons in area 17 of monocularly (MD) and binocularly (BD) deprived Siamese cats were studied. Neither condition produced a loss of cortical responsiveness, which is a characteristic result of binocular deprivation in normally pigmented cats. Somewhat more units in the deprived hemisphere of MD Siamese cats were orientation-selective, and many more units were direction-selective than in BD Siamese cats. This difference may be due to an effect of visual attentional mechanisms, which can function in MD but not BD Siamese cats. To test whether the resistance to the effects of visual deprivation in Siamese cats might be a more general phenomenon. Siamese and normally pigmented cats were raised in an 8-Hz stroboscopically illuminated environment. Both groups showed a severe loss of direction selectivity. Some of the normally pigmented cats also showed a loss of binocularity, which appeared to be secondary to strabismus.