Structural variation of the monoamine oxidase A gene promoter repeat polymorphism in nonhuman primates.

By conferring allele-specific transcriptional activity on the monoamine oxidase A (MAOA) gene in humans, length variation of a repetitive sequence [(variable number of tandem repeat (VNTR)] in the MAOA promoter influences a constellation of personality traits related to aggressive and antisocial behavior and increases the risk of neurodevelopmental and psychiatric disorders. Here, we have analyzed the presence and variability of this MAOA promoter repeat in several species of nonhuman primates. Sequence analysis of MAOA's transcriptional control region revealed the presence of the VNTR in chimpanzee (Pan troglodytes), bonobo (Pan paniscus), gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus), rhesus macaque (Macaca mulatta) and Gelada baboon (Theropithecus gelada). The majority of P. troglodytes and P. paniscus showed a single repeat with a sequence identical to the VNTR sequence in humans. In contrast, analyses of the remaining species revealed shorter sequences similar to the first 18 bp of human VNTR. Compared with other nonhuman primates, the VNTR sequence of M. mulatta showed the highest length variability with allele frequencies of 35, 25 and 40% for the five, six and seven repeat variants, respectively. The extent of variability of the MAOA promoter repeat in both rhesus monkeys and humans supports the notion that there may be a relationship between functional MAOA expression and aggression-related traits in humans and rhesus macaque populations.

Primary biphasic lymphoplasmacytic lymphoma of the lung. A mucosa-associated lymphoid tissue lymphoma with compartmentalization of plasma cells in the lung and lymph nodes.

A primary mucosa-associated lymphoid tissue lymphoma of the lung in a 27-year-old man was found. The tumor was composed mainly of centrocyte-like cells and plasma cells. These two components were demarcated sharply from each other, resulting in a zoning or biphasic pattern. This characteristic pattern also was present in the involved regional lymph nodes. Monoclonality of tumor cells was shown immunohistochemically and by in situ hybridization techniques. This article also highlights the use of in situ hybridization in detecting light chain mRNA in paraffin sections.

Systemic lupus erythematosus and nodular regenerative hyperplasia of the liver.

A patient with systemic lupus erythematosus and nodular regenerative hyperplasia of the liver is presented.

Lymphoid tissue of the normal fallopian tube--a form of mucosal-associated lymphoid tissue (MALT)?

Mucosal-associated lymphoid tissue (MALT) is a specialized form of peripheral lymphoid tissue which is found in mucosal surfaces directly or indirectly exposed to the environment. Using immunohistological labeling techniques and electron microscopy, we have explored the possibility that MALT exists in the normal fallopian tube. Immunohistological analysis has demonstrated a striking degree of uniformity in the phenotype of intraepithelial lymphocytes with a predominance of T-lymphocytes of T-cytotoxic/suppressor subtype. Occasional intraepithelial macrophages are also present, but B-cells, T-helper cells, and natural killer cells are absent or are rarely found in the epithelium. Electron microscopy has provided morphological evidence of an interaction between epithelial cells and intraepithelial lymphocytes. The opposing plasma membranes of these two cell types are arranged in the form of complex interdigitations and laminations. These striking arrangements substantially increase the total area of contact between the two cell types. We conclude that MALT does exist in the fallopian tube and that epithelial cells form an integral part of the system. A hypothetical view of the relationship between these cell types is presented.

The effect of a low pH on the membrane skeleton of the erythrocyte ghost.

The effects of an acidic pH on the membrane skeleton of erythrocyte ghosts has been investigated by negative staining and thin-section methods. At neutral pH the membrane skeleton consisted of 6-7 nm wide filaments uniformly dispersed on the inner membrane surface. At pH 5.0 the filaments fused to form a coarse network with thick strands and large areas of membrane devoid of filaments. These changes were completely reversible in many cells. They can probably account for the clustering of surface anionic sites and membranous particles which occur at a low pH and may play a role in other related events such as the change in shape of the cell and increased membrane stiffness.

Myospherulosis: further ultrastructural observations.

The changes of myospherulosis were observed in masses from the buttocks of three patients. Ultrastructural examination of parent bodies and spherules from two patients revealed some spherules to contain dense bodies and filaments. Spherules had a double electron dense wall: the outer layer had a thickness corresponding to that of a cell membrane. Incubation of packed red blood cells with tetracycline ointment produced a similar electron dense deposit on the inner aspect of the cell membrane of the erythrocytes. No filaments or parent bodies were seen. Our findings support the hypothesis that myospherulosis represents altered red blood cells. The filaments seen in our patients may represent polymers of haemoglobin. It is suggested that parent bodies may be derived from histiocytes.

The ultrastructural organization of the contractile peripheral protein layer of the human erythroycte membrane.

Erythroycte ghosts fixed in glutaraldehyde were dehydrated in (a) alcohol or acetone, (b) propylene glycol followed by Epon and embedded in an epoxy resin. A water-soluble urea/glutaraldehyde mixture was also used. The aim was to study the structure of the peripheral protein layer, which contains spectrin and actin, in the absence of OsO4 induced denaturation changes. Ghost membranes prepared in this way had an asymmetrical quadrilaminar structure. A layer of amorphous peripheral protein +/- 18 nm in width covered the entire inner face of the membrane in the form of a coarse meshwork in both Wash I (haemoglobin-containing) and haemoglobin-free ghosts. Cations (Mg2+ or Ca2+, or Mg2+ plus ATP) had no apparent effect on its fine structure. In contrast, the corresponding layer in OsO4-fixed membranes was represented by scanty, fuzzy material attached to the unit membrane only at irregular intervals. The results demonstrate the superior ability of glutaraldehyde to preserve the peripheral protein layer in thin sections, and afford further support for the view that much of this protein normally exists in an unpolymerized state.

Hyperplastic foci in precancerous rat liver: light microscopic and electron microscopic study.

4-Dimethylaminoazobenzene was fed to Wistar-derived, male, albino rats after hepatic siderosis had been induced by including ferric citrate in the diet. Iron-free foci of hepatocytes developed and this characteristic enabled them to be recognized macroscopically in the brown parenchyma. Five such lesions, each 1 mm or less in diameter, were studied by light and electron microscopy. The cells in the foci were larger than those surrounding the foci and had a granular and moderately basophilic cytoplasm. Ultrastructurally, the cells closely resembled normal hepatocytes. They possessed well-developed rough endoplasmic reticulum, numerous free ribosomes, peroxisomes, bile canaliculi, and cytoplasmic junctional complexes, but only small stores of glycogen were observed. Occasional ferritin-laden lysosomes persisted in some cells. These foci were regarded as hyperplastic. Possibly, they evolved into hyperplastic nodules either of the basophilic or vacuolated type. These foci should be clearly distinguished from hyperbasophilic foci that consisted of very poorly differentiated cells.

Nocardia infections in congenitally athymic (nude) mice and in other inbred mouse strains.

The mortality rate and histopathological features of Nocardia asteroides and Nocardia brasiliensis infections in congenitally athymic (nude) mice of ICR and C3H/eB origins were quite different from what we found for Swiss white mice and other inbred mouse strains (namely, C57/BL/6J, New Zealand Black, BALB/c, CBA/LAC, and C3H/eB). The immunocompetent littermates of the congenitally athymic mice occupied an intermediate position between their athymic siblings and Swiss white mice in terms of their responses to both these organisms. Macrophage ingestion and destruction of N. brasiliensis, as demonstrated by electron microscopy, was found to occur. The T-lymphocyte appears to be an essential component in normal mouse resistance to infection by both N. asteroides and N. brasiliensis.

Pancreatic islets of malnourished rats: quantitative histologic and electron microscopic findings.

Young rats were maintained for three weeks on a low-protein diet. These animals developed many of the features of human protein-calorie deficiency, including dextrose intolerance and diminished insulin release. Quantitative histologic and ultrastructural studies showed that malnourished rats had (1) a reduced total pancreatic islet volume, and (2) a preponderance of pale granules in the B cells. It is suggested that pale B granules may contain increased amounts of insulin, which accumulate in the cells because of defective insulin release. The mechanism responsible for this has not been elucidated.

Diffuse arteritis, long-term immunosuppression and malignancy.

A 45-year-old White man presented with multiple aneurysm formation and severe constitutional symptoms, the control of which entailed long-term corticosteroid therapy. Early in the patient's clinical course, two aneurysms were resected, and at subsequent postmortem examination the vascular lesions were found to be inactive and fibrosed, which suggested that the corticosteroids had been effective in controlling the inflammatory reaction. Of special interest was the development of diffuse lymphoma of the large cell type (histiocytic lymphoma) late in the course of the disease. This report emphasises the association between immunosuppressive therapy and subsequent neoplasia, and stresses the need for caution in the administration of these agents to patients whose condition is benign.