An ikaros-containing chromatin-remodeling complex in adult-type erythroid cells.

We have previously described a SWI/SNF-related protein complex (PYR complex) that is restricted to definitive (adult-type) hematopoietic cells and that specifically binds DNA sequences containing long stretches of pyrimidines. Deletion of an intergenic DNA-binding site for this complex from a human beta-globin locus construct results in delayed human gamma- to beta-globin switching in transgenic mice, suggesting that the PYR complex acts to facilitate the switch. We now show that PYR complex DNA-binding activity also copurifies with subunits of a second type of chromatin-remodeling complex, nucleosome-remodeling deacetylase (NuRD), that has been shown to have both nucleosome-remodeling and histone deacetylase activities. Gel supershift assays using antibodies to the ATPase-helicase subunit of the NuRD complex, Mi-2 (CHD4), confirm that Mi-2 is a component of the PYR complex. In addition, we show that the hematopoietic cell-restricted zinc finger protein Ikaros copurifies with PYR complex DNA-binding activity and that antibodies to Ikaros also supershift the complex. We also show that NuRD and SWI/SNF components coimmunopurify with each other as well as with Ikaros. Competition gel shift experiments using partially purified PYR complex and recombinant Ikaros protein indicate that Ikaros functions as a DNA-binding subunit of the PYR complex. Our results suggest that Ikaros targets two types of chromatin-remodeling factors-activators (SWI/SNF) and repressors (NuRD)-in a single complex (PYR complex) to the beta-globin locus in adult erythroid cells. At the time of the switch from fetal to adult globin production, the PYR complex is assembled and may function to repress gamma-globin gene expression and facilitate gamma- to beta-globin switching.

Ethanol induces the formation of water-permeable defects in model bilayers of skin lipids.

We show that ethanol can induce the formation of water-permeable defects in model membranes of skin, providing a fresh perspective on ethanol as a membrane modulator. We rationalise our findings in terms of the chemical nature of ethanol, i.e., a combination of its hydrogen bonding propensity and amphiphilic character.

The use of indirect immunofluorescence to evaluate the gel filtration method of fractionating human immunoglobulins.

The indirect immunofluorescent technique has been shown to be a more sensitive method than either immunoelectrophoresis or gel filtration for testing the efficacy of the gel filtration method in fractionating human immunoglobulins. It has been confirmed that IgM fractions of some sera from patients with multiple sclerosis, contain antibody which reacts with measles virus-infected tissue culture cells.

Serum iron, total iron-binding capacity, and percentage saturation in normal subjects.

The serum iron was determined in 60 normal subjects (38 males and 22 females) with a mean age of 32.0 and 36.2 years respectively. The plasma total iron-binding capacity (TIBC) was also determined in 54 of these subjects (32 males and 22 females). Serum iron and TIBC determinations were performed between 8.45 am and 9.15 am. The mean serum iron concentration is 138.3 +/- 4.3 mug/100 ml (SD +/- 32.9 mug/100 ml), and the mean TIBC is 470.1 +/- 6.8 mug/100 ml (SD +/- 50.1 mug/100 ml); the mean plasma siderophilin saturation is 30.0%. The mean values for serum iron, TIBC, and siderophilin saturation are similar in both sexes. They are normally distributed, and there is no significant correlation of serum iron and TIBC with age in either males or females.

Use of the 'Analmatic clinical system' in the microbiological assay of vitamin B 12 and folic acid in serum.

The routine estimation of large numbers of serum folic acid and vitamin B(12) levels using the Baird and Tatlock(1) Analmatic clinical system is described and the method evaluated.Precision, accuracy, and carryover are shown to be at acceptable levels, and the advantages and disadvantages of the use of the system are discussed. It is considered that with some modifications the Analmatic system offers a reliable and labour-saving method of carrying out considerable numbers of routine microbiological assays.

The effect of pancreatectomy and other agents on iron absorption and storage in the rat.

Evidence from both animal and human studies had been presented by various authors to suggest that reduction of pancreatic function increased iron absorption. The present experimental studies in rats showed that there was increased radioiron ((59)Fe) absorption after pancreatectomy, but this appeared to be due to the operative procedure as there was a similar increased absorption in animals who had sham operations performed. There was no certain evidence that pancreatic enzymes or extract had a specific inhibitory effect on the absorption of iron. But with increased doses of pancreatic extract, above the normal doses, the amount of radioiron absorption was greatly enhanced.A significant increase in hepatic storage iron was found in the groups of rats who had been fed a diet supplemented with dl-ethionine. All these animals showed extensive damage and atrophy of the pancreas, with degeneration and considerable regenerative activity in the liver. The absolute increased hepatic storage iron was not due to the liberation and laying down of haemosiderin from the damaged cells or to decreased liver mass. Rats who had carbon tetrachloride-induced liver cirrhosis without pancreatic damage showed no increased hepatic storage iron. It was observed that in liver damage with considerable cellular proliferation there was increased liver iron content. As this was found only when there was associated pancreatic injury, it is suggested that decreased pancreatic function in the presence of liver cell injury with cellular proliferation leads to increased iron absorption and storage. The relationship of liver injury with cellular proliferation and pancreatic damage to increased hepatic storage iron merits further study.

Urinary amino acid excretion in subjects with leukaemia.

Urinary amino acid chromatograms were studied from 33 patients with various types of leukaemia and 71 control subjects. Marked variations were found in the excretion of methionine, threonine, valine, leucine, tyrosine, histidine, and aspartic acid.

A revised scheme for the evaluation of automatic instruments for use in clinical chemistry.

A revised scheme is described for evaluating automatic instruments used in clinical chemistry. Procedures are outlined for the assessment of mechanical and electrical features, and measurement of the accuracy and precision of individual units. Methods are given for the measurement of analytical precision, carryover, cross-contamination, accuracy, and linearity. The safety of equipment and methods of assessing costs are discussed, and the importance of subjective features is noted. The general principles of the evaluation scheme should be applicable to other types of equipment.

A recommended scheme for the evaluation of kits in the clinical laboratory.

A scheme for kit evaluation in the individual clinical chemistry laboratory is presented. Recommendations for assessing accuracy, precision, and stability are included along with a scheme for preparing for the evaluation and writing the final report.

A prospective study of liver enzyme and other changes following repeat administration of halothane and enflurane.

A prospective study of liver enzymes and other measurements following repeat administrations of halothane or enflurane was carried out in patients undergoing minor urological operations. The patient populations were similar with respect to frequency of factors which might influence liver function, social habits, drug therapy and time intervals between administrations. Sixty-three received two or more administrations of halothane and 66 received two or more administrations of enflurane, both drugs given with nitrous oxide in oxygen. There was a greater frequency of increased enzymatic activity following repeat administrations of halothane than following enflurane and the average alanine aminotransferase and gamma glutamyl transpeptidase concentrations were increased to a greater degree following halothane than enflurane. There was no change in the eosinophil count and no significant postoperative morbidity. Change in alanine aminotransferase, lactate dehydrogenase and gamma glutamyl transpeptidase occured more frequently in obese patients receiving halothane.