Complement activation by malignant B cells from patients with chronic lymphocytic leukaemia (CLL).

It has previously been reported that the expression of the complement receptors CR1 (CD35) and CR2 (CD21) on malignant B cells in CLL is reduced compared with the expression on normal B cells, while deposition of complement C3 fragments, as a consequence of alternative pathway (AP) activation of complement, is observed on mononuclear cells from patients with B CLL. Following our demonstration that normal B cells are capable of activating the AP of complement in a CR2-dependent fashion, we have chosen to re-examine the complement-activating ability of B CLL cells in relation to their altered phenotype with respect to CR2 and the complement regulatory membrane proteins, CR1, decay accelerating factor (DAF) (CD55) and membrane cofactor protein (MCP) (CD46). Flow cytometry was used to measure expression of complement receptors and regulatory proteins on CD5+ B cells from CLL patients, as well as the deposition of C3 fragments occurring both in vivo and after in vitro AP activation. We have confirmed the reduced expression of CR1 and CR2 on CLL cells and have shown that AP activation in the presence of homologous, normal serum was reduced on B CLL cells compared with normal B cells. The degree of AP activation correlated directly with CR2 expression. In addition, we observed that CLL cells bear in vivo-deposited C3d,g, although at a significantly lower level than normal B cells.     

Quantitative studies of Fc receptors on human monocytes: characterization by binding of homologous and heterologous monomeric IgG and soluble immune complexes of different composition

The binding of 125I-labelled monomeric human and rabbit IgG (H-IgG, R-IgG) and rabbit IgG immune complexes (IC) to monocyte-enriched human peripheral blood cells had been investigated quantitatively. Scatchard plots at 4 degrees demonstrated that R-IgG bound to the same number of Fc receptors per cell (19,000) as H-IgG, but with a lower affinity (2.4 +/- 0.9 X 10(8)/l/mol and 3.5 +/- 1.1 X 10(8)l/mol, respectively). Inhibition studies demonstrated that the two ligands could mutually inhibit each other, H-IgG having higher inhibitory efficiency versus R-IgG than the reverse. It seems likely that R-IgG reacts with the Fc receptor for the homologous IgG, although with lower affinity. Binding of soluble R-IgG anti-bovine serum albumin (BSA) IC, prepared at molar antigen:antibody (Ag:Ab) ratio of 2:1 and 12:1, showed quite different behaviour, the IC binding with association constants almost 10-fold lower than the affinity of monomeric R-IgG, but binding six- to seven-fold as many IgG molecules per cell at saturation.     

No evidence for triallelic inheritance of MKKS/BBS loci in Amish Mckusick-Kaufman syndrome

It has been hypothesized that two mutations in one gene are not sufficient and that three mutations between two genes are required for penetrance in some cases of Bardet-Biedl syndrome (the so-called "triallelic inheritance" model). McKusick-Kaufman syndrome (MKS) is allelic to one form of Bardet-Biedl syndrome (BBS). We describe an Amish family with MKS, where three children were affected with homozygous MKKS (BBS6) mutations (H84Y and A242S on both alleles), their father was a carrier, and their mother was homozygous for the same MKKS mutations, but she was non-penetrant. Genotyping and/or sequencing of BBS1, BBS2, BBS3, BBS4, BBS5, BBS7, and BBS8 excluded "triallelic inheritance" for each gene either by an incompatible inheritance pattern or an absence of mutations in the coding region and the intronic splice junctions of these genes. We conclude that the "triallelic" model does not explain the incomplete penetrance of MKS.     

Primitive Neuroectodermal Tumors of the Central Nervous System

Controversial issues relating to the pathobiology and classification of central nervous system primitive neuroectodermal tumors (PNETs) have plagued neuropathologists for more than 70 years. Hypotheses advanced in the mid-1920's have remained as fixed concepts in contemporary literature, largely consequent to repetitious support by a small number of neuropathologists despite a growing body of information discrediting these ideas from neuroembryologists, oncologists, neuroscien-tists and pathologists.
Attention has largely focused upon PNETs arising in the cerebellum (commonly known as medul-loblastomas [MBs]), because about 80% of central nervous system (CNS) PNETs originate in this site. It has been asserted that the 20% which do not are biologically different, although most individuals agree that the histological features of PNETs that occur in different sites throughout the CNS are indistinguishable from those growing in the cerebellum.
The historical aspects of this controversy are examined in the face of evidence that there is, in fact, a unique class of CNS tumors which should appropriately be regarded as primitive neuroectodermal in nature. Specifically, a number of different approaches to the problem have yielded data supporting this hypothesis. These approaches include the identification of patterns of expression among a variety of cellular antigens (demonstrated by the use of immunopathological techniques), molecular analyses of cell lines derived from these tumors, experimental production of PNETs and molecular genetic analyses.
Differences of opinion among surgeons, oncologists and radiotherapists are typically resolved by conducting cooperative studies of patients with these tumors who are diagnosed and treated at multiple centers.     

Aberrant actin cytoskeleton leads to accelerated proliferation of corneal epithelial cells in mice deficient for destrin (actin depolymerizing factor)

Corneal disease is the most common cause of bilateral blindness in the world. Visual loss in this condition is often due to changes in morphology and function of the corneal epithelial surface. Corneal disease-1 (corn1) and corn1(2J) are spontaneous mouse mutants that develop irregular thickening of the corneal epithelium, similar to that observed in human corneal surface disease. These autosomal-recessive mutations cause an increase in the rate of proliferation of the corneal epithelial cells. Here, we report that the phenotypes in both mutants are caused by mutations within the destrin gene (also known as actin-depolymerizing factor). By positional cloning, we identified a deletion encompassing the entire coding sequence of the destrin gene in corn1 mice, and a point mutation (Pro106Ser) in the coding sequence of destrin in corn1(2J) mice. In situ analysis showed that destrin is highly expressed in the corneal epithelium. Consistent with the cellular roles for destrin, an essential regulator of actin filament turnover that acts by severing and enhancing depolymerization of actin filament, we observed that the corn1 mutations increased the content of filamentous actin in corneal epithelial cells. Our results suggest an in vivo connection between remodeling of the actin cytoskeleton and the control of cell proliferation, and a new pathway through which an aberrant actin cytoskeleton can cause epithelial hyperproliferation.     

Low serum haemolytic function of the fourth complement component (C4) in insulin dependent diabetes.

Low serum concentrations of the fourth component of complement (C4) are found in insulin dependent diabetes, and may be important in the aetiology of the disease. To ascertain whether function of C4 is also impaired both its haemolytic activity and its concentration were measured in 34 insulin dependent diabetics, 15 non-insulin dependent diabetics, 20 healthy subjects, and 12 pairs of monozygotic twins discordant for insulin dependent diabetes. C4 function was measured by a radial immune haemolytic assay, and C4 concentration by laser nephelometry. Both measurements were significantly lower in insulin dependent diabetics (C4 function: median 47%, range 4-100%; C4 concentration: 0.22 g/l, 0.10-0.38 g/l) than in non-insulin dependent diabetics (67%, 33-138%, p less than 0.01; 0.27 g/l, 0.16-0.50 g/l, p less than 0.02) and controls (74%, 33-138%, p less than 0.01; 0.27 g/l, 0.18-0.40 g/l, p less than 0.03). C4 function and concentration were lower in both diabetic (48%, 12-100%; 0.17 g/l, 0.08-0.31 g/l) and non-diabetic twins (47%, 12-100%; 0.17 g/l, 0.07-0.36 g/l) than controls (p less than 0.01; p less than 0.01). Thirteen (38%) of the insulin dependent diabetics had a reduction in either C4 function or concentration, but in only five were both features reduced. Values of function and concentration were strongly correlated in both diabetic and non-diabetic twins (r = 0.95, p less than 0.001; r = 0.92, p less than 0.001). These results show defects in C4 function and concentration in insulin dependent diabetes, which--being present in the non-diabetic co-twin of diabetics--may represent a genetic predisposition to the disease.     

Polyorna virus adsorbs to specific sialyloligosaccharide receptors on erythrocytes

Hemagglutination by polyoma virus has been shown to require sialic acid residues on cell surface oligosaccharides. This report presents evidence which suggests that adsorbtion of polyoma virus to erythrocytes is not due simply to a nonspecific electrostatic interaction with negatively charged sialic acids but rather requires the presence of specific sialyloligosaccharide structures. Newcastle disease virus (NDV) neuraminidase hydrolyzes sialic acids in the sequences NeuAcα2,3Gal and NeuAcα2,8NeuAc. Erythrocytes treated with NDV lost 40% of their surface sialic acid, retained full hemagglutination by certain influenza viruses which also bind sialyloligosaccharides, and yet were not agglutinated by polyoma virus. Erythrocytes treated with Vibrio cholerae neuraminidase, which removes virtually all sialic acid, were no longer agglutinated by influenza virus or polyoma virus. Selective replacement of sialic acid on V. cholerae neuraminidase-treated cells with purified β-galactoside α-2,3-sialytransferase in the sequence NeuAcα2, 3Gal completely restored hemagglutination by polyoma virus. In contrast, replacement of sialic acid by other sialyitransferases in the sequences NeuAcα2,6Gal or NeuAcα2,6GalNAc does not restore hemagglutination by polyoma virus.     

An evaluation of semen analysis and in-vitro tests of sperm function in the prediction of the outcome of intrauterine AIH

Twenty-nine couples with an average of 5 years of infertilitywere selected for treatment by intrauterine insemination ofwashed semen (AIH). The criteria for selection were (i) thefemale partner showed no detectable fertility disorders by routinescreening; (ii) the male partner showed subnormal semen qualityon conventional semen analysis. Ovulation was stimulated uniformlywith clomiphene citrate and precipitated with human chorionicgonadotrophin (HCG). Inseminations were performed 31–32h post-HCG, with the day of HCG determined by ultrasound monitoringof follicular development. The fertilizing capacity of the malepartners‘ spermatozoa was tested in vitro using donatedhuman oocytes and/or the zona-free hamster oocyte penetrationassay. Up to eight cycles of AIH were alternated with cyclesof natural intercourse. While no pregnancies occurred in thegroup during normal coital cycles, the AIH pregnancy rate was17% per couple, but only 3% per insemination cycle. Four furtherpregnancies were achieved spontaneously in couples from thestudy group within 3 years of completion of the AIH therapyand four patients became pregnant following subsequent GIFTor IVF treatments. Neither of the in-vitro tests was helpfulin predicting the outcome of AIH, spontaneous pregnancy norof subsequent assisted conception procedures.     

Detection of Leishmania infantum kinetoplast DNA in laryngeal tissue from an immunocompetent patient

Mucosal leishmaniasis of the upper respiratory tract is usually associated with the visceral form or is found in immunosuppressed individuals. This report presents a case of isolated mucosal leishmaniasis in an immunocompetent patient, whose diagnosis mainly rested on histology and positive polymerase chain reaction result for Leishmania donovani in the laryngeal tissue. A 59-year-old man, who never lived outside Italy, showed a subglottic mucosal polypoid-like lesion. The typical morphological picture and positive polymerase chain reaction result for L donovani by DNA extracted from laryngeal biopsy specimens allowed the diagnosis of mucosal leishmaniasis. Specific amphotericin B therapy was started, resulting in clinical and endoscopic improvement. Increased knowledge about the histological and molecular tissue analysis of Leishmania enhances the diagnostic testing for mucosal leishmaniasis, as primary mucosal leishmaniasis may occur in both immunosuppresed and immunocompetent patients who travel to or reside in areas endemic for Leishmania.     

Galactose metabolism in mice with galactose-1-phosphate uridyltransferase deficiency: sucklings and 7-week-old animals fed a high-galactose diet

Mice deficient in galactose-1-phosphate uridyltransferase (GALT) demonstrate abnormal galactose metabolism but no obvious clinical phenotype. To further dissect the pathways of galactose metabolism in these animals, galactose oxidation and metabolite levels were studied in 16-day-old sucklings and the effect of a 4 week prior exposure to a 40% glucose or 40% galactose diet was determined in 7-week-old mice. Suckling GALT-deficient (G/G) mice slowly oxidized [1-14C]galactose to 14CO2, 4.0% of the dose when fed and 7.9% when fasted compared to normal animals 38.3 and 36.4% in 4 h, respectively. Plasma of G/G sucklings contained 11.1 mM galactose and erythrocyte galactose 1-phosphate levels were 28.2 and 31.9 mg/dl packed cells. Galactose, galactitol, galactonate, and galactose 1-phosphate were found in G/G suckling mouse tissues. The tissue galactose concentrations were 10% or less of that in plasma, suggesting that there was limited cellular entry of galactose. In 7-week-old fasted mice with 4 weeks prior exposure to glucose or galactose-containing diet, 4-h oxidation was 12.9 and 15.0% of the administered radiolabeled galactose, respectively. Normal animals oxidized 33.9 and 37.9% of the dose when fed the same diets, respectively. The ability of G/G mice to oxidize galactose in the absence of GALT activity suggests the presence of alternate metabolic pathways for galactose disposition. G/G mice fed the galactose-free 40% glucose diet had erythrocyte galactose 1-phosphate levels ranging from 6.4 to 17.7 mg/dl packed cells and detectable galactose and galactose metabolites in tissues, suggesting that these animals endogenously produced galactose. The plasma of 40% galactose-fed G/G mice contained 9.1 mM galactose with red blood cell galactose 1-phosphate averaging 43.6 mg/dl. Tissues of these animals also contained high levels of galactose and galactose 1-phosphate. Liver contained over 4 micromol/g galactonate but little galactitol. Despite the elevated galactose and galactose 1-phosphate, the animals tolerated the high-galactose diet and were indistinguishable from normal animals, exhibiting no manifestations of galactose toxicity seen in human GALT-deficient galactosemia. The data suggest that high galactose 1-phosphate levels do not cause galactose toxicity and that high galactitol in combination with galactose 1-phosphate may be a prerequisite. Absence of GALT appears necessary but insufficient to produce human galactosemic phenotype.