Enzymatic-Ultraviolet Method for Measuring Lactose in Milk: Collaborative Study

Collaborators in 8 dairy and food industry laboratories performed one lactose determination on each of 8 unknown samples of milk, lowfat milk, or skim milk, as 3 pairs of blind duplicates. Two known samples were provided to gain experience prior to analysis of the unknown samples. All of the above samples were also analyzed for lactose content by the official AOAC gravimetric method (16.507) by a commercial laboratory. From the overall mean of results on all samples, determinations by the enzymatic method averaged 0.49% lower than by the AOAC method. This difference was significant by the t-test (P = 0.05), which indicated a lack of agreement between the compared methods in determining lactose content. Standard deviations were similar for the 3 sets of blind duplicates which ranged between 3.67 and 4.55% lactose content. F-values revealed that variations between means obtained by laboratories differed significantly as compared with variations within laboratory means. The method has been adopted official first action.

RANK receptor oligomerisation in the regulation of NFκB signalling

The interaction of receptor activator of NFκB (RANK), a member of the tumour necrosis factor receptor superfamily, with RANK ligand is crucial for the formation, function and survival of osteoclasts. The role of the cytoplasmic oligomerisation domain (pre-ligand assembly domain; PLAD or 'IVVY' motif) in the ligand-dependent activation of downstream NFκB signalling has not been studied previously. The discovery of truncating mutations of TNFRSF11A (W434X and G280X that lack the PLAD) as the cause of rare cases of osteoclast-poor osteopetrosis offered the opportunity for functional study of this region. Recapitulating the W434X mutation by transcription activator-like effector nuclease (TALEN)-mediated targeted disruption of Tnfrsf11a within the region homologous to W434X in the mouse macrophage-like cell line RAW264.7 impaired formation of osteoclast-like cells. Using overexpression studies, we demonstrated that, in contrast to WT-RANK, the absence of the PLAD in G280X-RANK and W434X-RANK prevented ligand-independent but not ligand-dependent oligomerisation. Cells expressing W434X-RANK, in which only two of the three TRAF6-binding motifs are present, continued to exhibit ligand-dependent NFκB signalling. Hence, the absence of the PLAD did not prevent ligand-induced trimerisation and subsequent NFκB activation of RANK, demonstrating that therapeutic targeting of the PLAD in the prevention of osteoporosis may not be as effective as proposed previously.

Non-psychiatric comorbidity associated with Alzheimer's disease

The burden of medical comorbidity in individuals with Alzheimer's disease is greater than that observed in matched individuals without dementia. This has important implications for all clinicians and healthcare providers who deal with this common condition. The prevalence of vascular risk factors and vascular disease is particularly high. Additionally, associations with a number of other chronic medical conditions have been described, including thyroid disorders, sleep apnoea, osteoporosis and glaucoma. This review gives an overview of evidenced medical (non-psychiatric) comorbidity associated with Alzheimer's disease and briefly explores the underlying mechanisms that may account for these associations.

Beryllium(II) Complexes of the Kläui Tripodal Ligand Cyclopentadienyltris(diethylphosphito-P)cobaltate(−)

The interactions of the beryllium(II) ion with the cyclopentadienyltris(diethylphosphito-P)cobaltate monoanion, L(-), have been investigated, in aqueous solution, by synthetic methods, potentiometry, ESMS, and (1)H, (31)P, and (9)Be NMR spectroscopy. L(-) has been found able to displace either two or three water molecules in the beryllium(II) coordination sphere, to form mononuclear, dinuclear, and trinuclear derivatives, in which the metal ion is pseudotetrahedrally coordinated. The species [BeL(H(2)O)](+) and [Be(2)L(2)(mu-OH)](+) have been identified in solution while complexes of formula BeL(2) and [Be(3)L(4)](ClO(4))(2) have been isolated as solid materials. The species [BeL(OPPh(2))](+), closely related to [BeL(H(2)O)](+), has been characterized in acetone solution and isolated as tetraphenylborate salt. The structure of the unusual trimeric complex [Be(3)L(4)](2+) has been elucidated by an unprecedented 2D (9)Be-(31)P NMR correlation spectrum showing the presence of a single central beryllium nucleus and two equivalent terminal beryllium nuclei. The three beryllium centers are held together by four cobaltate ligands, which display two different bonding modes: two ligands are terminally linked with all the three oxygen donors to one terminal beryllium, and the other two bridge two metal centers, sharing the oxygen donors between central and terminal beryllium atoms.

The major histocompatibility complex influences the development of chronic liver disease in male children and young adults with cystic fibrosis

BACKGROUND/AIMS

Chronic liver disease is a well-recognised complication of cystic fibrosis. Recent reports suggest that its development is not determined by specific mutations within the cystic fibrosis gene; however, familial clustering of portal hypertension cases and inappropriate immune responses against liver membrane antigens demonstrated in children with cystic fibrosis and chronic liver disease suggest that other genetic loci may be relevant. As the major histocompatibility complex has an important immunoregulatory role, we have investigated for associations with this complex and chronic liver disease in cystic fibrosis.

METHODS

We have determined human leucocyte antigen class I (A and B) and class II (DR) phenotypes by serological tissue typing and class II (DR and DQ) and class III (complement component C4 and 21-hydroxylase) gene polymorphisms in 274 children and young adults with cystic fibrosis, of whom 82 had evidence of chronic liver disease with portal hypertension in 49, and 146 healthy controls.

RESULTS

A marked difference in human leucocyte antigen frequency was limited to DQ6, which was found in 66.7% of cystic fibrosis patients with liver disease compared to 32.9% of patients with no liver disease (Pc < 0.03) and 28.8% of controls (Pc < 0.006). An increased frequency of the two antigens in strong linkage disequilibrium with DQ6 was also observed within this patient group, namely DR15 and B7. When the patients were stratified for the presence of portal hypertension, these observations were confirmed, but the human leucocyte antigen associations were significant only for male patients and there was no association with the age of onset of liver disease.

CONCLUSIONS

These data suggest that the haplotype B7-DR15-DQ6 may carry an increased risk of development of liver disease in male cystic fibrosis patients.

Allelic sequence variation in the HLA class II genes and proteins in patients with autoimmune hepatitis

Susceptibility to autoimmune hepatitis in white patients is associated with the human leukocyte antigen class II antigens DR3 and DR4. To analyze the molecular basis of these associations, we used oligonucleotide probes to determine the DRB, DQA and DQB hypervariable nucleotide sequences in 119 patients with autoimmune hepatitis and 177 matched controls. DRB3*0101, which encodes DR52a, predisposed patients most strongly to the disease. It was present in 58% of patients and 25% of controls (corrected P < 0.000005), whereas DQA1*0101 and 0102 conferred protection in males only. The DR4 subtype, DRB1*0401, was raised in the DRB3*0101-negative patients; 81% possessed either DRB3*0101 or DRB1*0401, compared with 42% of controls (corrected P < 0.0000001). These alleles encode the amino acid sequence Leu-Leu-Glu-Gln-Lys-Arg at positions 67 to 72 of the DR beta polypeptide, which was present in 94% of patients and 64% of controls (corrected P < 0.000001) and in all patients who tested positive for autoantibodies to the hepatic asialoglycoprotein receptor. The patients with DRB1*0401 had less severe disease, relapsed less frequently and were first seen significantly later in life than those patients with DRB3*0101; and whereas a single copy of DRB1*0401 predisposed to autoimmune hepatitis, DRB3*0101-associated susceptibility had a dose-related effect. These data provide evidence that specific residues in the DR beta polypeptides predispose to autoimmune hepatitis in white patients and genes linked to DRB3*0101 and DRB1*0401 may determine two clinically distinct disease patterns.

Genotype analysis for delta F508, G551D and R553X mutations in children and young adults with cystic fibrosis with and without chronic liver disease

Genetic factors have been implicated in the pathogenesis of liver disease in cystic fibrosis. To investigate whether liver disease is associated with particular mutations of the defective gene in cystic fibrosis, we have determined the frequencies of three mutations--delta F508, G551D and R553X--in 111 children and young adults with cystic fibrosis by analysis of genomic DNA segments amplified by the polymerase chain reaction. Twenty-nine patients had severe liver disease with portal hypertension, 19 had clinical and/or biochemical evidence of liver disease but no associated portal hypertension and 63 had no evidence of liver disease. No significant differences in the frequencies of the delta F508, G551D or R553X mutations in the three clinical subgroups were found, and we conclude that the development of liver disease in cystic fibrosis is unlikely to be associated with a specific mutation in the gene. However, because 27% of cystic fibrosis chromosomes do not have a defined mutation, this possibility cannot be ruled out. A familial concordance for clinical liver disease of 20% in this study, compared with a reported prevalence of 4.7%, suggests that genes outside the cystic fibrosis locus and/or environmental factors are involved in the pathogenesis of liver disease in cystic fibrosis.

HLA phenotypes and gene polymorphisms in juvenile liver disease associated with alpha 1-antitrypsin deficiency

Chronic liver disease affects up to 20% of children with alpha 1-antitrypsin deficiency owing to the PiZZ genotype. Previous observations of a familial occurrence and abnormal immune responses to liver antigens in these patients suggests that immunoregulatory genes may be involved in the pathogenesis of liver damage. We have identified HLA phenotypes and class II (HLA-DR) gene polymorphisms in 140 white PiZZ subjects, of whom 92 (83 index patients) had liver disease, and 206 first-degree relatives. DR3* was present in 35 of 75 (46.7%) unrelated patients with liver disease compared with 5 of 28 (17.8%) patients without (p less than 0.01) and 23 of 100 controls (p less than 0.001). DR4 was increased in patients without liver disease; it was present in 17 of 28 (60.7%) compared with 29 of 75 (38.7%) patients with liver disease (p less than 0.05) and 36 of 100 controls (p less than 0.025). Using Southern blot analysis with HLA-DRB and DQB DNA probes, we identified two polymorphisms of DR3, only one (Dw25) of which is raised in PiZZ individuals with liver disease (9 of 55: 16.4%) compared with 1 of 23 (4.4%) without and 2 of 52 (3.9%) controls (p less than 0.05). Analysis of the segregation of HLA haplotypes in 77 families revealed no concordance for liver disease with HLA in those with affected sibships, indicating that, although DR3-Dw25 is associated with liver disease in alpha 1-antitrypsin deficiency, other factors must play a pathogenic role.

Fatal cholestatic jaundice in elderly patients taking benoxaprofen

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