Gastrointestinal arterial fibromuscular dysplasia of childhood

An unusual case of a progressive, noninflammatory stenosing vasculopathy, arterial fibromuscular dysplasia is presented. The distinctive features of this particular case include onset in early childhood with a predominant involvement of the gastrointestinal system, sparing of the renal arteries, lack of hypertension, and no cutaneous features of progressive systemic sclerosis. We discuss the clinical history over a decade and the pathologic features, including routine and electron microscopic findings of biopsy and autopsy tissues, and review the literature.

Origin of mesenchymal tissue in the septum primum: a structural and ultrastructural study

A structural, ultrastructural and histochemical study in chick embryos indicates that the septum primum mesenchymal tissue originate between 3 and 5 days of development and that their origin may be related to an activation of endocardial cells that cover the septum primum. By day 3, endocardial cells display migratory appendages, cell hypertrophy and an increase in secretory and mitotic activity. In later stages (day 4) hypertrophic endocardial cells undergoing division seem to delaminate and translocate toward the subendocardial space to give rise to free mesenchymal-type cells. These results suggest that the endocardium makes up the bulk of the septum primum mesenchymal tissue as has been demonstrated during mesenchymal tissue formation in the atrioventricular canal and outflow tract. Before and during mesenchymal tissue formation an accumulation of extracellular matrix components like proteoglycans can be visualized using tannic acid. These extracellular components might be related to the promotion of cellular events described during endocardial activation. The fusion of the septum primum with the atrioventricular (AV) endocardial cushions which would obliterate the foramen primum, occurs between mesenchymal tissues. Therefore, any alteration in the normal development of these mesenchymal tissues could be related to pathological cases of persistent atrial communications. Light microscopy preliminary observations of embryonic mouse heart indicate that septum primum mesenchymal tissue formation occurs similarly between mouse and chick embryos.

Structure-activity relationships among di- and tetramine disulfides related to benextramine

The synthesis and irreversible alpha-blocking activity in the rat vas deferens of a series of tetra- and diamine disulfides 2-38, structural analogues of benextramine (BHC), are described. All compounds containing a central cystamine moiety displayed an irreversible alpha-adrenergic blockade at concentrations ranging from 10(-4) to 6 X 10(-6)M. Potency was increased in cystamines N,N'-disubstituted with 6-aminohexyl groups, especially when the outer nitrogen atoms bear arylalkyl substituents or are enclosed in a ring. However, N,N,N',N'-tetrasubstituted cystamines were poor blockers. Structural specificity in the outer portion of the tetramine disulfide is low, since many types of substituents gave rise to potent alpha-blockers. Even replacement of the outer amines with nonbasic ethers or amides was observed to maintain irreversible alpha-blockade.

Mesenchymal tissue of the interventricular septum. Structural and ultrastructural study

Light and electron microscopic studies of frontal and sagittal sections of embryonic chick hearts (Stages 25, 28-29), reveal mesenchymal tissue in the cephalic portion of the interventricular septum. The endocardium of this cephalic portion contains reoriented and invaginated cells with pseudopodia; in addition there are cells immediately subjacent to the endocardium. Similar cellular events take place during the formation of mesenchymal tissue in the atrioventricular and conotruncal regions. In these regions the mesenchymal tissue originates by means of an endocardial activation process. The structural characteristics of the formation of the cephalic portion of the interventricular septum suggest that local mesenchymal tissue is contributed by the endocardium. However, based upon the close anatomic relationship observed by us between the mesenchymal tissues of the atrioventricular canal, conotruncal region and the cephalic portion of the interventricular septum; we do not discard a contribution by migration of cells from atrioventricular and conotruncal regions to the interventricular septum.

Influence of the mesenchymal microenvironment on myocardial and endocardial cell behaviour in experimental interaction with chick limb mesenchyme

In an attempt to clarify the possible influence of the mesenchymal microenvironment in the differentiation of myocardial and endocardial cells, an "in vivo" transplantation experiment was performed in which the ventricular region of the heart (chick or quail) was placed in close association to the mesenchyme of the anterior chick limb to create an experimental interaction between myocardium and foreign mesenchyme. The results showed that after 48 h of tissue interactions the ventricular myocardium is incorporated into the mesenchyme of the anterior chick limb, changing its organization and cytological appearance. The myocytes tend to dissociate, exhibiting a less organized myofibrillar pattern. In addition, abundant extracellular matrix components made up of granular and fibrillar material were observed associated with the myocardial and the mesenchymal cell membranes as well as distributed in their surrounding microenvironment. The endocardium became discontinuous, due to detachment of the cells and emitted multiple pseudopodia and filopodia. These observations indicate that the mesenchyme from the anterior chick limb modifies the cellular behaviour and organization of the neighbouring myocardium and endocardium with which it interacts. We suggest that this might occur through participation of extracellular matrix components such as glycosaminoglycans, fibronectin and collagen which are known to act as macromolecular mediators in cell to cell interactions, cell migration and differentiation.

Prenatal diagnosis of fetal brain tumors

Two cases of congenital brain tumors were detected during routine antepartum sonography at the Mount Sinai Medical Center Perinatal Ultrasound Unit. In both cases, diagnosis was made during the third trimester at 31 and 33 weeks, respectively. In one of these patients, no intracranial abnormalities were noted on a sonogram performed in conjunction with genetic amniocentesis at 18 weeks gestation. The histologic diagnosis of both tumors was glioblastoma multiforme grade III. Previous reports describing the prenatal sonographic diagnosis of intracranial tumors have been in cases with fetal intracranial teratomas.

Features of enterotoxigenic Escherichia coli strains of porcine origin that express K88 and 987P fimbrial antigens

Escherichia coli strains of porcine origin express K88 and 987P pilus-antigens in vitro. This study reports their enterotoxin producing ability, serological features and plasmid content. The bipiliated strains were enterotoxigenic and all contained a large plasmid of uniform size.

In vitro activity of BRL 36650, a new semisynthetic penicillin

BRL 36650 [sodium 6 beta-(D-2-[(4-ethyl-2, 3-dioxopiperazin-1-yl)carbonylamino]-2-(3,4-dihydroxyphenyl) acetamido)-6 alpha-formamido-penicillinate] is a new semisynthetic penicillin. It was tested in vitro for activity against 884 organisms cultured from blood specimens of cancer patients. BRL 36650 had broad-spectrum activity against the gram-negative bacilli tested but had no gram-positive activity. The MIC against 90% of the Pseudomonas aeruginosa isolates was 3.12 micrograms/ml. The activity of BRL 36650 was superior to that of piperacillin, comparable or slightly inferior to that of aztreonam and ceftazidime, and lower than that of imipenem and amifloxacin. BRL 36650 should prove useful for the management of gram-negative bacillary infections, including those caused by P. aeruginosa.

Young men with high blood pressure report few recent life events

Men who had high, medium and low blood pressure at age 18 (compulsory screening for military service in Stockholm) were examined ten years later at age 28. Interviewers, having had no information regarding past or present blood pressure, interviewed them about life events experienced during the year preceding the examination. Men with high blood pressure at rest reported fewer life events for the past year than other men. Furthermore, high plasma adrenaline levels at rest were associated with few reported life events.

Ovarian cavernous hemangioma

Vascular tumors of the female genital tract are rare, especially those of the ovary. Most cases are small lesions that are discovered incidentally. We describe a 68-year-old woman with a benign hemangioma that presented clinically as a very large ovarian mass.

Electron microscopic diagnosis of cerebral toxoplasmosis. Case report

Rapid and specific diagnosis of infections involving patients with acquired immunodeficiency syndrome (AIDS) is imperative. Toxoplasmosis is one of the most frequent causes of central nervous system disease in these patients. The authors present a case of cerebral toxoplasmosis in an AIDS patient, diagnosed by electron microscopy of brain biopsy tissue using rapid techniques.

Adenosquamous carcinoma of the colon

Two cases of primary adenosquamous carcinomas of the sigmoid colon and rectum are presented. Clinical features and pathologic findings of both primary and metastatic lesions are reported (including immunohistochemistry and electron microscopy). We emphasize that the presence of a metastatic squamous tumor in a patient with an unknown primary does not exclude the possibility of colonic carcinoma. Comparison with other reports in the American medical literature indicates that these are very aggressive tumors that may have a worse prognosis than the more common form of colonic adenocarcinoma. Furthermore, the squamous component, in particular, may have a greater potential for metastasizing and can do so as an undifferentiated-appearing carcinoma. In view of this, the authors suggest that very poorly differentiated areas within colonic adenocarcinomas should be very carefully evaluated by means of immunoperoxidase stains and/or electron microscopy in an attempt to identify squamous features.

Effects of Stevia rebaudiana natural products on rat liver mitochondria

The effects of several natural products extracted from the leaves of Stevia rebaudiana on rat liver mitochondria were investigated. The compounds used were stevioside (a non-caloric sweetener), steviolbioside, isosteviol and steviol. Total aqueous extracts of the leaves were also investigated. S. rebaudiana natural products inhibited oxidative phosphorylation, ATPase activity NADH-oxidase activity, succinate-oxidase activity, succinate dehydrogenase, and L-glutamate dehydrogenase. The ADP/O ratio was decreased. Substrate respiration (state II respiration) was increased at low concentrations (up to 0.5 mM) and inhibited at higher concentrations (1 mM or more). In uncoupled mitochondria, inhibition of substrate respiration was the only effect observed. Net proton ejection induced by succinate and swelling induced by several substrates were inhibited. Of the compounds investigated, the sweet principle stevioside was less active. It was concluded that, in addition to the inhibitory effects, S. rebaudiana natural products may also act as uncouplers of oxidative phosphorylation. The possible physiologic consequences of the ingestion of stevioside and S. rebaudiana aqueous extracts are discussed.

Effect of steviol and its structural analogues on glucose production and oxygen uptake in rat renal tubules

The effect of several natural products of Stevia rebaudiana on glucose production and oxygen uptake in rat renal cortical tubules was investigated. Steviol, isosteviol and glucosilsteviol decreased glucose production and inhibited oxygen uptake. The sweet principle stevioside, and steviolbioside, however, were without effect on gluconeogenesis and oxygen uptake.

Kinetics and mechanism of enzymatic hydrolysis of pivampicillin monolayers

A study of the enzymatic hydrolysis of pivampicillin (an insoluble penicillin) extended as a monolayer on the aqueous interface at a constant surface pressure has been performed. Penicillinase promotes intensive hydrolysis of the pivampicillin monolayers, inducing their solubility. However, no action was observed with dog liver esterase. The hydrolytic process, which was dependent on the film surface pressure and on the quantity of the injected enzyme, is of the Michaelis-Menten type in two dimensions.