The pigeonhole of occult hepatitis B.

Occult hepatitis B (OHB), or persistent hepatitis B virus (HBV) viremia in surface-antigen-HBsAg-negative patients, has been recognized as a medical concern during the last decade. The exact magnitude, pathogenesis and clinical relevance of OHB are unclear. This review organizes the published data on OHB and presents an overview of the current hypotheses on OHB's pathogenesis and clinical relevance.Many explanations have been offered for the pathogenesis of OHB, ranging from the inability of standard immunoassays to diagnose OHB to the involvement of the versatile virus-host factors. Also, special care should be taken regarding the diagnosis of OBH. It seems that both shared viral-host factors are involved in the pathogenesis of OBH. Further molecular studies on cohort patients group need to explore such association.

Isolation and expression in Escherichia coli of cslA and cslB, genes coding for the chondroitin sulfate-degrading enzymes chondroitinase AC and chondroitinase B, respectively, from Flavobacterium heparinum.

In medium supplemented with chondroitin sulfate, Flavobacterium heparinum synthesizes and exports two chondroitinases, chondroitinase AC (chondroitin AC lyase; EC 4.2.2.5) and chondroitinase B (chondroitin B lyase; no EC number), into its periplasmic space. Chondroitinase AC preferentially depolymerizes chondroitin sulfates A and C, whereas chondroitinase B degrades only dermatan sulfate (chondroitin sulfate B). The genes coding for both enzymes were isolated from F. heparinum and designated cslA (chondroitinase AC) and cslB (chondroitinase B). They were found to be separated by 5.5 kb on the chromosome of F. heparinum, transcribed in the same orientation, but not linked to any of the heparinase genes. In addition, the synthesis of both enzymes appeared to be coregulated. The cslA and cslB DNA sequences revealed open reading frames of 2,103 and 1,521 bp coding for peptides of 700 and 506 amino acid residues, respectively. Chondroitinase AC has a signal sequence of 22 residues, while chondroitinase B is composed of 25 residues. The mature forms of chondroitinases AC and B are comprised of 678 and 481 amino acid residues and have calculated molecular masses of 77,169 and 53,563 Da, respectively. Truncated cslA and cslB genes have been used to produce active, mature chondroitinases in the cytoplasm of Escherichia coli. Partially purified recombinant chondroitinases AC and B exhibit specific activities similar to those of chondroitinases AC and B from F. heparinum.

A different approach to treatment of phenylketonuria: phenylalanine degradation with recombinant phenylalanine ammonia lyase.

Phenylketonuria (PKU), with its associated hyperphenylalaninemia (HPA) and mental retardation, is a classic genetic disease and the first to have an identified chemical cause of impaired cognitive development. Treatment from birth with a low phenylalanine diet largely prevents the deviant cognitive phenotype by ameliorating HPA and is recognized as one of the first effective treatments of a genetic disease. However, compliance with dietary treatment is difficult and when it is for life, as now recommended by an internationally used set of guidelines, is probably unrealistic. Herein we describe experiments on a mouse model using another modality for treatment of PKU compatible with better compliance using ancillary phenylalanine ammonia lyase (PAL, EC 4.3.1.5) to degrade phenylalanine, the harmful nutrient in PKU; in this treatment, PAL acts as a substitute for the enzyme phenylalanine monooxygenase (EC 1.14.16.1), which is deficient in PKU. PAL, a robust enzyme without need for a cofactor, converts phenylalanine to trans-cinnamic acid, a harmless metabolite. We describe (i) an efficient recombinant approach to produce PAL enzyme, (ii) testing of PAL in orthologous N-ethyl-N'-nitrosourea (ENU) mutant mouse strains with HPA, and (iii) proofs of principle (PAL reduces HPA)-both pharmacologic (with a clear dose-response effect vs. HPA after PAL injection) and physiologic (protected enteral PAL is significantly effective vs. HPA). These findings open another way to facilitate treatment of this classic genetic disease.

Isolation and expression in Escherichia coli of hepB and hepC, genes coding for the glycosaminoglycan-degrading enzymes heparinase II and heparinase III, respectively, from Flavobacterium heparinum.

Upon induction with heparin, Flavobacterium heparinum synthesizes and secretes into its periplasmic space heparinase I (EC 4.2.2.7), heparinase II, and heparinase III (heparitinase; EC 4.2.2.8). Heparinase I degrades heparin, and heparinase II degrades both heparin and heparan sulfate, while heparinase III degrades heparan sulfate predominantly. We isolated the genes encoding heparinases II and III (designated hepB and hepC, respectively). These genes are not contiguous with each other or with the heparinase I gene (designated hepA). hepB and hepC were found to contain open reading frames of 2,316 and 1,980 bp, respectively. Enzymatic removal of pyroglutamate groups permitted sequence analysis of the amino termini of both mature proteins. It was determined that the mature forms of heparinases II and III contain 746 and 635 amino acids, respectively, and have calculated molecular weights of 84,545 and 73,135, respectively. The preproteins have signal sequences consisting of 26 and 25 amino acids. Truncated hepB and hepC genes were used to produce active, mature heparinases II and III in the cytoplasm of Escherichia coli. When these enzymes were expressed at 37 degrees C, most of each recombinant enzyme was insoluble, and most of the heparinase III protein was degraded. When the two enzymes were expressed at 25 degrees C, they were both present predominantly in a soluble, active form.

High prolactin levels may be missed by immunoradiometric assay in patients with macroprolactinomas.

OBJECTIVE: Large amounts of antigen may produce falsely low values in immunoradiometric assays due to the so-called high dose, hook effect. The study was designed to identify the clinical and biochemical features of patients with pituitary macroadenomas in whom a high dose PRL hook effect was documented. DESIGN: The clinical and biochemical features of four patients with the high dose PRL hook effect were compared with those of 54 patients with pituitary non-functioning adenomas and 11 with macroprolactinomas who underwent transsphenoidal microsurgery between 1989 and 1994. MEASUREMENTS: The presence of the high dose PRL hook effect was confirmed by an increase in the initial PRL concentration when the immunoradiometric assay was processed after dilutions of the serum. This phenomenon was observed in 5.8% (4/69) of patients with pituitary macroadenomas. Undiluted median (range) PRL levels were 9140 (1530-83850), 1530 (162-3210) and 2110 mU/l (1470-45,000) in patients with macroprolactinoma, non-functioning macroadenoma and the hook effect, respectively. In patients with the hook effect, the median PRL levels increased to 384,720 (317,520-950,000) mU/l when the assay was performed after serum dilution. The proportion of males was 9.9% (1/11) in the macroprolactinoma group, 46.3% (25/54) in the non-functioning macroadenoma group and 100% (4/4) in patients with the hook effect. Patients with prolactinoma and non-functioning adenoma had mean tumour sizes of 20 +/- 9 and 27 +/- 11 mm (SD), respectively, while in the hook effect group it was 51 +/- 10 mm. CONCLUSION: This study suggests that the high dose PRL hook effect is observed particularly in patients with very large tumours. The immunoradiometric PRL assay must be performed with serum dilution in order to overcome the high dose PRL hook effect in all new patients with pituitary macroadenomas who may have a prolactinoma.

The carboxy-terminal 18 amino acids of the measles virus hemagglutinin are essential for its biological function.

The hemagglutinin (HA) glycoprotein encoded by measles virus (MV) is a type II integral membrane protein that is expressed at the infected cell surface. Genes encoding wild-type MV HA as well as two mutant HA proteins shortened at their carboxy-termini by either 18 (HA delta 18O) or 223 (HA delta 223) amino acids were constructed and studied in a transient expression system in COS cells. Under nonreducing conditions, assembly of HA delta 18 into homodimers was diminished while HA delta 223 remained in a monomeric form. Hemadsorption assays revealed that neither mutant was functional at the cell surface. These studies show that the carboxy-terminal ectodomain of the HA protein is essential to its proper folding and assembly into homodimers while its carboxy-terminal 18 amino acids are essential for the hemadsorption (receptor-binding) function of the protein.

[Double contrast radiological exploration of the major duodenal papilla (author's transl)]. / Exploration radiologique de la grande caroncule duodénale en double contraste.

The major duodenal papilla can be outlined in 75% of cases by double contrast examination. It is composed of an oval-shaped nodule covered by a mucous cap which is prolonged into a frenum in its lower part. Its mean dimensions are 11 X 7 X 6 mm. Many variations are observed, and these are analyzed as well as the features suggesting pathological modifications. These may arise from inflammation: during the course of primary or secondary (ulcer, pancreatitis) duodenitis, or be related to a stone blocked in the region of the ampulla. Tumors in this region are rare, and are usually malignant tumors, the characteristics and extension of which can be determined from radiological images. Use of this radiological technique as a preliminary step enables a complete study of the upper digestive tract to be conducted at the same time.

[Angiographic signs of extra-dural hematomas of the posterior fossa (author's transl)]. / Aspects angiographiques des hématomes extra-duraux de la fosse postérieure. Formes aiguës et subaiguës.

Traumatic subacute and acute extra-dural hematomas of the posterior fossa are infrequent lesions which can be considered as exceptional From 1973 to 1977, we have collected 12 such cases. We performed 11 carotid angiographies and 7 vertebral angiographies in the series. Only in one case among 5 did clinical signs suggested a lesion of the posterior fossa. One of the best clinical elements to suggest such a lesion is the presence of a fracture line that crosses the lateral sinus, which necessitated a complete angiographic study. Arteriographic signs are function of the topography of the hematoma. The carotid angiography reveals only the supratentorial extension of the extra-dural collection of the blood clot. The most frequent sign is a filling defect of the affected sinus. The classic sign of detachment of the torcular is seen only in about 25% of cases. Vertebral angiography shows the existence of an expanding posteroinferior mass of the posterior fossa. Axial views always permits to find the avascular zone which corresponds to the extra-dural collection of the blood clot. In addition, vertebral angiography permits a good study of the sinusal drainage of the posterior fossa. In the purpose to find a supra-tentorial extension the prognosis of the extra-dural hematoma depends on its early discovery. The procedure of choice to make and to confirm such a diagnosis is vertebral angiography and it is not necessary to perform a carotid angiography in the cases where a supra-tentorial lesion does not seen associated.

[Annular pancreas in the adult (author's transl)]. / Le pancréas annulaire de l'adulte.

Annular pancreas--a congenital malformation consisting of a ring of pancreatic tissue around the second part of the duodenum--is a rare surgical condition in adults. It may be responsible for occlusion in the newborn, but frequently remains latent or does not reveal itself until adulthood, usually around the age of 40. The only symptoms are ulcer-like epigastric pains; vomiting occurs at a late stage and jaundice irregularly. Hypotonic duodenography shows, at best, duodenal stenosis, the extrinsic origin of which is disclosed by fiberoscopy. Pre-operative investigations should aim at detecting a gastro-duodenal ulcer or an associated chronic pancreatitis. Owing to the presence of an excretory duct within the ring, section of the latter entails a risk of fistulisation. The best prospects of cure are offered by digestive tract derivation procedures: latero-lateral duodeno-duodenostomy, gastro-enterostomy and duodeno-jejunostomy on a Y-shaped excluded jejunal loop.

[Double contrast hypotonic duodenography]. / La duodénographie hypotonique en double contraste.

Double contrast hypotonic duodenography, as carried out by the authors, is a simple and rapid examination, suitable for routine use. At the same time, it includes a double contrast study of the oesophagus and stomach. The normal appearance is easily analysed, in particular that of the great caronculus. It is a selective examination of the duodenal outline, playing an essential role in the detection of lesions of the latter as well as in adjacent organs which may alter its shape. It provides only a suggestion as to aetiology and must therefore be completed, when appropriate, by other studies.

[Pathogenic considerations in an association of systemic sclerodermia, Gougerot-Sjögren syndrome and active chronic hepatitis]. / Considérations pathogéniques a propos de l'association a une sclérodermie systémique d'un syndrome de Gougerot-Sjögren et d'une hépatite chronique active

The authors, report a case of scleroderma associated with Sjogren's syndrome and chronic active hepatitis, and propose a series of theories on the relationship between these 3 conditions. Each is successively considered as the cause of the two others through a cellular immune deficiency although the possibility of a chance association cannot be excluded.