Analysis of HeLa cell hypoxanthine phosphoribosyltransferase mutants and revertants by two-dimensional polyacrylamide gel electrophoresis: evidence for silent gene activation

The spot corresponding to hypoxanthine phosphoribosyltransferase (HPRT; IMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.8) has been identified in two-dimensional polyacrylamide gels of HeLa cell extracts. This spot is absent in gels of 24 HPRT dificient mutants. A missense mutant displays a new HPRT spot at the same molecular weight but different isoelectric focusing position. Five independently isolated revertants of the missense mutant display spots corresponding to both the wild-type and mutant proteins indicating that they synthesize HPRT from two separate genes. If the missense protein is synthesized from a mutated form of the initially active HPRT gene, then wild-type HPRT protein in the revertants must be snythesized from a newly activated but prevously silent wild-type gene. The newly activated gene in the revertants of the missense mutation appears unstable producing a high frequency of spontaneous HPRT mutants.

A study of HL-A types in Rh haemolytic disease of the newborn

The HL-A types of 288 women, immunised to the Rh(D) antigen as a result of pregnancy, have been compared to the HL-A types of 139 women who although they have had Rh(D)-positive children have not produced anti-Rh(D). There is an indication that an increased incidence of the HL-A3 antigen is associated with the immunised mothers. A study of the HL-A types of husbands and children of both immunised and non-immunised women did not suggest that their HL-A types played a significant role in anti-Rh(D) production. The frequencies of the HL-A antigens in each category studied have been tabulated for record purposes, as well as the frequencies in a random panel of persons living in the Newcastle environs. Full ABO, Rh and HL-A details of 50 immunised mothers and their families and of 58 non-immunised mothers and their families are available.

Unusual clonal evolution in a case of chronic myelogenous leukemia

Several unusual cytogenetic changes have occurred during the evolution of chronic myelogenous leukemia in a 32-year-old white male with this disease for 8 years. The first appearance of a hypodiploid cell line containing a dicentric marker occurred 2 years after diagnosis and this line was eliminated by several courses of therapy with hydroxyurea. A second clone, which had a partial deletion of the long arm of one of the number 8 chromosomes (8q-) was noted a year later, but this line has been refractory to intensive combination chemotherapy.

Superiority of conventional intrathecal methotrexate therapy with maintenance over intensive intrathecal methotrexate therapy, unmaintained, or radiotherapy (2000-2500 rads tumor dose) in treatment for meningeal leukemia

In the treatment of patients with meningeal leukemia, conventional intrathecal methotrexate therapy followed by maintenance intrathecal methotrexate at intervals of 8 weeks has been shown superior to an intensive, unmaintained intrathecal methotrexate induction regimen, and to neuroaxis radiotherapy, tumor dose 2000-2500 rads. In each of the treatment regimens, all children completing proscribed therapy achieved complete CNS remission as judged by the return of CSF findings to normal. Median lengths of remission were: maintenance regimen 240 days; intensive induction regimen, 106 days; and radiotherapy, 216 days. Differences were of statistical significance between the maintenance regimen and the intensive regimen (p equal 0.001), and between the radiotherapy and intensive regimens (p equal 0.01). Maintenance intrathecal therapy appeared to affect favorably the duration of existing marrow remissions; the median time to marrow relapse for patients given maintenance therapy was significantly longer than for those given intensive induction therapy. Toxicity of the chemotherapy regimens was not prohibitive. Radiotherapy was associated with severe myelosuppression, interruptions of systemic therapy, and serious infections, which resulted in death in five children.

Split ileostomy in the treatment of Crohn's disease of the colon

Because of the problems associated with surgical resection of Crohn's disease of the colon a more conservative approach has been used in Oxford since 1960. The inflamed large bowel has been defunctioned by an external diversionary ileostomy and subsequently the disease has been treated with topical and oral corticosteroids. The technique of the split ileostomy used for this purpose is described and the indications for the operation and early results of its use in 69 patients are recorded. In carefully chosen cases the method has two advantages over primary resection. In some patients the inflammation improved sufficiently for continuity of the bowel to be restored without resection being necessary and without medical treatment being required. In others the ileostomy resulted in a marked improvement in general health which has made the subsequent major resection a safer procedure. As an extension of the technique the use of an external faecal diversion by ileostomy is recorded in a further 11 patients who had a synchronous resection of a segment of bowel affected by Crohn's disease.

Acute appendicitis complicating pregnancy in the Oxford region

A study of 75 patients who were admitted to the Oxford group of hospitals with suspected acute appendicitis during pregnancy is presented, and the findings are compared with those in a similar group of non-pregnant patients. In general the disease was found at operation to be more advanced in the pregnant group, and this was probably a reflection of a delay in diagnosis. This delay, which was seen most commonly in the third trimester, led to a number of fetal deaths which might have been avoided by earlier operation. Furthermore, the dangers resulting from a negative laparotomy were sufficiently minor for a policy of early surgery for suspected acute appendicitis to be advocated during all stages of pregnancy.

The effect of obstructive jaundice on the migration of reticulo-endothelial cells and fibroblasts into early experimental granulomata

Clinical and experimental evidence indicates that obstructive jaundice inhibits the healing of wounds. Experiments in the rat designed to investigate the migration of reticulo-endothelial and fibroblasts into experimental granulomata are described. Standard preparations of obstructive jaundice and controls were devised using Wistar rats. The effects of bile-duct obstruction and sham ligation are described. In another group of animals which was similarly prepared granuloma-pouch experiments were carried out by burying sterile cotton-wool pledgets of a known weight. These peledgets were removed from the jaundiced and control animals on the third, fifth, seventh, and ninth days after implantation, dried to remove the fluid component of the inflammatory process, and weighed on a microbalance. The weights were compared and it was found that a significant inhibition of weight increase occurred in the jaundiced animals during the first week, suggesting a delay in the migratory activity of reticuloendothelial cells and fibroblasts.

The effect of experimental bile-duct obstruction on critical biosynthetic functions of the liver

Using biosynthetic activities which have a maximum energy requirement, the effect of obstruction of the bile-duct has been studied in isolated perfused rat livers, and compared with controls undergoing “sham” ligation and with normal animals. The maximum rate of gluconeogenesis from lactate was inhibited by 67 per cent after bile-duct ligation when compared with the normal value. The maximum rate of urea synthesis which occurred in the presence of ornithine was the same in the jaundiced and in the normal animals. ‘Sham’ operation, without ligation of the bile-duct, inhibited gluconeogenesis by less than 20 per cent but doubled the maximum rate of urea synthesis.

It is concluded that complete biliary obstruction seriously impairs gluconeogenesis and prevents the normal increase of urea synthesis which occurs in response to trauma and that these changes develop earlier than might be expected after the onset of obstruction.

Some possible mechanisms of these effects are discussed. If similar abnormalities of hepatocyte function are demonstrated in man it is suggested that surgical relief of obstructive jaundice is indicated at an early stage.

Organization and administration of the orthopedic nursing unit

Sociologic and economic factors, as well as developments in science, in medical practice, and in nursing, have coincided to make the hospital orthopedic nursing unit one of relatively short-term, intensive patient care and intensive preparation for the rehabilitation period to follow. Some administrative arrangements which hold promise for the furthering of patient care objectives are found in the areas of physical plant, personnel, supply and equipment, and communications.