Metastasizing basal cell carcinoma originating in a stasis ulcer in a black woman

A case of basal cell carcinoma originated in a long-standing stasis ulcer on the lower extremity and then metastasized to the dermis and subcutaneous tissue of the thigh. The literature on metastasizing basal cell carcinoma is reviewed.

Urbanization and national development: the quest for appropriate human settlement policies in the Arab world

"The subject matter of this paper is policy perspectives of human settlement of the Arab countries in the light of the rapid urbanization trends largely resulting from the economic growth of the last two decades or so.... Section A analyzes the human settlement structure of the Arab countries and the urbanization processes of the recent past, and Section B picks up the threads from various documents and field observation to see what certain countries have done to solve the emerging problems and what directions their policies might take in the future." The paper is based on aggregate national data for 20 countries and on case studies of Egypt, Iraq, Jordan, Sudan, and Tunisia.

Sequence specificity in aflatoxin B1--DNA interactions

The activated form of aflatoxin B1 (AFB1) causes covalent modification primarily of guanine residues, leading to alkali-labile sites in DNA. A simple extension of the Maxam-Gilbert procedure for sequence analysis permits the identification of alkali-labile sites induced by AFB1 and determination of the frequency of alkali-labile AFB1 modifications at particular sites on a DNA fragment of known sequence. Using this strategy, we have investigated the influence of flanking nucleotide sequences on AFB1 modification in a number of DNA fragments of known sequence. Our results show that certain guanine residues in double-stranded DNA are preferentially attacked by AFB1 over others in a manner predictable from a knowledge of vicinal nucleotide sequences. The observed in vitro sequence specificity is independent of a number of tested parameters and is likely to occur in vivo.

Renal gamma-glutamyltranspeptidase: In situ antiluminal localization

Renal localization of gamma-glutamyltranspeptidase was studied in functioning kidneys perfused with the gamma-glutamyl substrates, gamma-glutamyl-p-nitroanilide and N(gamma-L-glutamyl) 2-naphthylamide. In kidneys perfused with gamma-glutamyl-p-nitroanilide, 90% of the breakdown products appear in the blood (perfusate) rather than urine. The addition of the acceptor substrate glycylglycine to the perfusate stimulated gamma-glutamyl-p-nitroanilide breakdown 3-fold, both on the blood and urine sides, while the appearance of gamma-glutamylglycylglycine confirmed that the activity responsible stems indeed from gamma-glutamyltranspeptidase. Ureter ligation reduced the glomerular filtration rate to less than 10% of the control, while the breakdown of gamma-glutamyl-p-nitroanilide decreased only 5%. Kidneys perfused with N(gamma-L-glutamyl) 2-naphthylamide and the diazonium salt demonstrated staining of the glomeruli; isolated glomeruli and microvessels gave heavy staining when incubated with the histochemical substrates. These results demonstrate the association of a significant portion of the total renal gamma-glutamyltranspeptidase activity with the microvascular compartment.

Recent studies on 'hyalinized' glomeruli

Hyalinized glomeruli in tissue sections those isolated from kidneys of subjected with end-stage and diabetic nephropathies and from aged persons (older than 75 years) were studied by histochemical, immunohistochemical, electron microscopic, and chemical methods. Our purposes were as follows: (1) to clarify the pathogenic mechanisms of glomerular hyalinization; (2) to resolve some of the controversies on terminology in the literature. Results showed significant increases in the amounts of collagen (13% to 30%), carbohydrates (30% to 47%), and lipids (58% to 82%), and decreases in the amounts of DNA (40%) and RNA (40% to 50%) in the hyalinized glomeruli of diseases compared with normally sized matched glomeruli. I conclude that glomerular hyalinization is a complex molecular pathogenic process.

Presence of gamma-glutamyltransferase in the renal microvascular compartment

The association between the brush border enzyme alkaline phosphatase and gamma-glutamyltransferase was determined by sucrose density gradient analysis of crude kidney homogenates, isolated glomeruli, and isolated microvessels. As previously established there is an overlap of these enzyme activities in the crude homogenate corresponding to a density of 1.17 g.cm-3. In contrast, isolated glomeruli sedimented with a peak of 1.25 g. cm-3 and exhibited gamma-glutamyltransferase activity but little alkaline phosphatase activity; homogenizing isolated glomeruli shifted the fragments to a density coincident with that observed for the crude homogenate gamma-glutamyltransferase peak. A second population of capillaries, isolated microvessels, were homogenized and analysed on the sucrose density gradient. These fragments sedimented over the same range as crude homogenate gamma-glutamyltransferase peak but were devoid of alkaline phosphatase activity and yet exhibited remarkable gamma-glutamyltransferase activity. The results indicate homogenization of renal cortex results in a heterogeneous collection of particles from both tubular and microvascular locations exhibiting gamma-glutamyltransferase activity which overlap with the brush border alkaline phosphatase containing membranes. However, isolation of microvessels and glomeruli prior to homogenization allows separation of gamma-glutamyltransferase from alkaline phosphatase activity; between 10 and 20% of the total homogenate gamma-glutamyltransferase activity is estimated to be associated with the microvascular compartment.

Spondyloepiphyseal dysplasia congenita. A comparative study of chondrocytic inclusions

Spondyloepiphyseal dysplasia congenita is a short-trunk chondrodysplasia trait. The abnormalities are present at birth and involve primarily the spine, the epiphyses of long bones, and the pelvis. Postmortem examinations of two patients with this disease who died shortly after birth showed a mild disorganization of chondrocytic columnization in the physeal growth zone. The chondrocytes contained PAS-positive cytoplasmic inclusions after diastase digestion to eliminate glycogen. Ultrastructural examination of the inclusions in one patient showed them to be accumulations of finely granular material in dilated cisterns of rough endoplasmic reticulum. To our knowledge, similar findings have been seen only in three other types of chondrodysplasia. The inclusions, which therefore are of diagnostic importance, may be of importance also in reflecting the primary metabolic abnormality.

Multiple pterygium syndrome

We describe a sporadic case and four sibs from a consanguineous Nicaraguan family affected with the multiple pterygium syndrome. Clinical manifestations included normal intelligence; short stature; pterygia of neck, axillary, antecubital, popliteal, digital, and intercrural areas; multiple joint contractures with a crouched stance; a flat, sad, motionless facial appearance; and cleft palate. Males had small penis and scrotum and cryptorchidism; females had apparent aplasia of labia majora and small clitoris. Skeletal anomalies included fusion of cervical vertebrae, scoliosis, flexion contractures of fingers and "rocker-bottom" feet with vertical talus. This review documents genetic heterogeneity: Autosomal recessive inheritance in many cases, autosomal dominant determination in others, and sporadic occurrence.

Glomerular basement membrane antigens of Masugi nephritis

Glomerular basement membrane (GBM) isolated from rat, dog and human kidneys were treated with enzymes to obtain soluble membrane preparations. Gel filtration on calibrated columns of soluble membrane preparations produced several macromolecules which were identified as glycoproteins and glycopeptides, depending on their molecular sizes. A sialoglycoprotein of 50,000 Daltons is shown to be the nephrotoxigenic antigen of the GBM. Lipids were shown to be a non-essential component of the nephrotoxigenic antigen. Collagen and several other glycopeptides were found to be non-nephrotoxigenic antigens of the GBM. Use of pronase or combinations of certain enzymes (for example, collagenase and pronase, pepsin and trypsin) to obtain the soluble components of the membrane led to an alteration of the nephrotoxigenic antigen molecule.