Separation by cation-exchange high-performance liquid chromatography of three forms of Chinese hamster ovary cell-derived recombinant human interleukin-2

Purified recombinant (r) interleukin 2 (IL-2) produced by a transformed Chinese hamster ovary cell line shows a single peak when analysed by reversed-phase high-performance liquid chromatography, but it can be resolved into three forms by sodium dodecyl sulphate polyacrylamide gel electrophoresis. These three forms were successfully isolated by narrow-bore ion-exchange chromatography through optimization of the elution conditions. The addition of n-propanol as an organic modifier to the mobile phase proved to be essential for the recovery of the protein from the column in a yield of 90% or better based on protein quantification and biological activity determination. This chromatographic method was used for the purification of these three rIL-2 forms which represent variable glycosylation of a single polypeptide chain. A comparison of the biological activities using the murine CTLL-2 cell proliferation assay showed that the specific activities of the three forms are similar.

Human recombinant interleukin-1 beta isolated from Escherichia coli by simple osmotic shock

A synthetic gene coding for the C-terminal 153 amino acids of the human interleukin-1 beta (IL-1 beta) was used to produce large quantities of recombinant IL-1 beta in Escherichia coli. The expression of the synthetic gene was under the control of an inducible promoter. The recombinant protein was released from the cells by an osmotic shock. This procedure did not lyse the cells. The IL-1 beta that represented 90% of the total extracted protein was purified to homogeneity by a single chromatographic step. Sequence analysis revealed a heterogeneous N-terminal sequence resulting from the cleavage of the N-terminal methionine in 50% of the molecules and of both the N-terminal methionine and alanine in the other 50%. This recombinant IL-1 beta had a specific activity of 1.3 x 10(8) international units per mg.

[Metopic craniosynostosis. Surgical results in 35 surgically treated cases under 1 year of age]

The clinical features, the diagnostic findings and the surgical results obtained on 35 children, under 1 year of age, operated on because of an early synostosis of the metopic suture are presented. In 79% of cases, the diagnosis was obvious at birth. A M/F ratio of 2.0 was observed in this series. Associated malformations were recorded in eleven patients (30.5%). The surgical procedure consisted of bilateral frontal craniectomy, opening of the roof of the orbit, advancement of the superior orbital margin, and repositioning of the frontal flaps after 180 degrees rotation. The cosmetical correction was satisfactory even in the immediate postoperative period. No mortality was recorded. The surgical correction was followed by a normal psychomotor development in 33 cases; delayed milestones were recorded in 2 children in whom the metopic synostosis was part of a complex malformative syndrome. On the grounds of our results, the young age of the patients at the operation should not be regarded as an obstacle to the immediate surgical correction; in our advice, the early correction results also in better functional and cosmetic long-term outcomes.

Peripheral nerve autografts to the rat spinal cord: a study of the origin of regenerating fibres using fluorescent double labelling

In adult Wistar rats a segment of the right sciatic nerve was grafted to the right dorsal funiculus of the spinal cord (SC). After survivals of 25-54 weeks a solution of the retrograde fluorescent cytoplasmatic tracer Fast Blue (FB) was injected into the SC and microgranules of the retrograde fluorescent nuclear tracer Diamidino Yellow (DY) were inserted into the graft. DY labelled neurones were found in the SC up to 30 mm both rostrally and caudally to the graft and were always single labelled. DY labelled cells were also found in the dorsal root ganglia (DRG) for 6-7 consecutive levels caudally to the graft. Ten to 30% of the DY labelled DRG cells were double labelled and also contained the FB tracer. The present work using the multiple retrograde fluorescent tracing method demonstrates that peripheral nerve (PN) grafts implanted in the rat SC are reinnervated by axones arising from intrinsic SC neurones and DRG cells. The axones from intrinsic SC neurones seem to result only from the regrowth of damaged neurones which have lost their intraspinal projections. The regeneration from DRG cells seem to be sustained by both the regrowth of damaged axones and the preterminal and/or collateral sprouting.

Characterization of recombinant glycosylated human interleukin 2 produced by a recombinant plasmid transformed CHO cell line

A recombinant plasmid containing expression units for human pre-interleukin 2 (pre-IL-2) and the selectable marker mouse DHFR, was constructed and used to transform DHFR- CHO cells to the DHFR+ phenotype. Selected colonies were isolated and tested for IL-2 production. Twelve highly IL-2-producing clones were amplified in stepwise increasing concentrations of methotrexate. The IL-2 secreted into the culture medium by one of these clones was purified to homogeneity and partially characterized. N-terminal sequence analysis showed that pre-IL-2 was correctly processed during secretion. SDS gel electrophoresis and chromatofocusing experiments in conjunction with neuraminidase treatment indicated a posttranslational glycosylation of the secreted mature protein similar to that described for the tetrasaccharide structure of the N2 form of natural IL-2. This recombinant IL-2 has a specific activity of 2.5 x 10(7) U/mg.

[Infection by Mycoplasma pneumoniae. Epidemiologic investigation and statistical clinical study of 122 children admitted to the Institute of Pediatrics of the University of Florence during the period 1 January 1977 to 31 December 1983]

We carried out an epidemiologic research about M. Pneumoniae infection from 1977 to 1983: determination of CF antibodies has been performed by the Bacteriology and Virology Laboratory (Prof. Lamanna, USL 10/D, Florence). Serum samples were collected by the laboratory itself and by hospitals and university departments of Florence and neighbouring communes. Our research confirms cyclic behaviour of M. Pneumoniae infection: we could follow up a 3 years long epidemic after a previous 2 years long endemic disease. We found a major sera-positive rate for M. Pneumoniae in children than in adults. In the same period we carried out a clinical-statistical study on 122 children (80 males and 42 females) admitted to the Pediatric Institute "A. Meyer" in Florence because of an infection due to M. Pneumoniae. The most affected age range sems to be included between 5 and 10 years. Pneumonia is the commonest clinical feature of M. Pneumoniae infection (85.2%): furthermore, we must point out some cases in 0-2 years-old subjects. In our patients, clinical features, X-ray findings and laboratory tests strictly agree with those reported by other authors. We treated all our patients with erythromycin: in three weeks we obtained thee normalization of clinical patterns and X-ray findings in all cases.