Biosynthesis and proteolytic processing of type XI collagen in embryonic chick sterna.

The biosynthesis and proteolytic processing of type XI procollagen was examined using pulse-chase labelling of 17-day embryonic chick sterna in organ culture with [3H]proline. Products of biosynthesis were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with and without prior reduction of disulfide bonds. Pro-alpha chains, intermediates, and matrix forms were identified by cyanogen bromide or Staphylococcus aureus V8 protease digestion.

Successful treatment of severe Rh iso-immunization with immunosuppression and plasmapheresis.

Nine patients with severe Rh iso-immunization were treated by plasma exchange combined with immunosuppression. Apart from 3 abortions, previous pregnancy losses consisted of 7 intra-uterine and 5 neonatal deaths. Only 2 patients had had no previous pregnancy loss.

The effects of furosemide and bumetanide on lung liquid production by in vitro lungs from fetal guinea pigs.

Lungs from fetal guinea pigs of 61 +/- 3 days of gestation were supported in vitro for 3 h, and lung liquid secretion rates were measured by a dye dilution technique based on Blue Dextran 2000. Ten preparations that had received no treatment showed an average secretion rate of 1.12 +/- 0.

Fluid production by in vitro lungs from fetal guinea pigs.

Lungs from fetal guinea pigs (54-67 days of gestation) were supported in vitro, and lung liquid secretion rates were measured by a dye-dilution technique. The average secretion rate in the first hour was 2.14 +/- 0.

Role of the leader peptide of maltose-binding protein in two steps of the export process.

During the process of export of maltose-binding protein to the periplasm of Escherichia coli, the leader peptide is involved in at least two steps. The presence of the leader portion of maltose-binding protein was shown to be necessary to mediate initial binding of the precursor to the membrane. However, the presence of a mutationally altered leader which does not sustain export in vivo was sufficient to allow this interaction.

A signal sequence mutant defective in export of ribose-binding protein and a corresponding pseudorevertant isolated without imposed selection.

Ribose-binding protein is exported to the periplasmic compartment of Escherichia coli by a process that involves proteolytic cleavage of an amino-terminal extension of amino acids from the precursor form of the protein. In a collection of mutants isolated as defective in the Rbs transport system, a strain was identified that contained only precursor ribose-binding protein, none of which was exported to its normal location in the periplasm. The mutated rbsB contained a base substitution that results in a change of leucine to a proline at position-17 in the signal sequence.

Dephosphorylation of thiamin pyrophosphate by fresh human plasma.

Thiamin pyrophosphate was added to human plasma and serum. After various incubations, aliquots were assayed by the thiochrome method. This revealed that fresh human plasma dephosphorylated thiamin pyrophosphate by a reaction that was time and temperature dependent and inhibited by the presence of ethylenediaminetetraacetic acid (EDTA).

Intestinal absorption of thiamin in man compared with folate and pyridoxal and its subsequent urinary excretion.

off intestinal absorption of thiamin was compared with that of folate and pyridoxal in six healthy volunteers using an oral dose of each vitamin equivalent to ten times the recommended daily allowance. Folate and pyridoxal were rapidly absorbed and following the oral dose, serum concentrations rose from a mean basal level of 10.9 micrograms/liter and 17.

Clinical trial of a milk formula for infants of low birth weight.

An infant milk formula specially designed to meet the specific needs of the small premature infant was compared with a modified infant milk formula in common use. Healthy infants of very low birth weight were fed with either the specially designed infant milk formula or the standard modified infant milk formula. No statistically significant differences between the two groups of infants were found, although the weight gain, skinfold thickness, serum total protein, albumin and calcium values were marginally better at 28 days in the group fed with the specially designed formula.

A microbiological assay for the measurement of methotrexate in biological fluids.

A microbiological assay for the measurement of methotrexate has been designed, using a chloramphenicol resistant mutant of Lactobacillus casei as the test organism. The method is simple, precise and inexpensive. Results are not significantly different from those obtained using a methotrexate radioassay kit employing a competitive protein binding technique.

The effect of intravenous amino acids on plasma amino acid concentration during total parenteral nutrition in infants with necrotizing enterocolitis.

Plasma aminograms of infants receiving total parenteral nutrition as part of the treatment for necrotizing enterocolitis were studied. Their ages varied from 2 to 60 days and their mean birth mass was 1 621 g (range 760-2 550 g). The intravenous administration of amino acids produced changes in plasma amino acid levels corresponding to the concentration of individual amino acid levels in the solution employed: higher levels of amino acids in the infusate produced increased plasma levels, whereas low plasma levels were obtained for amino acids not present or present in small amounts according to the solution used.

The influence of refined carbohydrate on urinary calcium excretion.

In the course of study of the influence of varying the amount of refined carbohydrate (sugar and sugar products) in an otherwise standardised diet in 18 normal subjects it was evident that the analysis of 24-h urine collections failed to show the profound diurnal variation in urinary electrolyte excretion and, in particular in this instance, calcium excretion. The analysis of individually voided specimens showed some normal subjects to have spontaneously high peaks of urinary calcium concentration throughout the day even whilst on a diet with low refined carbohydrate content. Increase in the refined carbohydrate content of the otherwise standardised diet caused significant increase in the number of urines with a calcium concentration above 9 mmol/1.

Clinical and cytogenetic aspects of the 21 deletion syndrome.

The clinical, cytogenetic and dermatoglyphic findings in a patient with a ring chromosome 21 are presented. This anomaly acts as a deletion of chromosomal material and results in specific congenital defects. A comparison is made with 24 cases of deletions involving chromosome 21 described in the literature.