Detection of transforming genes by transfection of DNA from primary soft-tissue tumours

A series of adult soft-tissue tumours were screened for the presence of activated oncogenes by transfecting tumour DNA into NIH3T3 mouse fibroblasts. In these studies an activated K-ras gene that contained a mutation at the second position of codon 12 (GGT----GAT) was found in a leiomyosarcoma. In addition, following transfection of DNA from a liposarcoma, we identified an activated gene that failed to hybridize to probes prepared from 10 known human oncogenes (K-ras, H-ras, N-ras, ret, met, trk, mas, dbl, raf and hst) that have previously been detected in DNA transfection experiments. BamHI-BamHI fragments of this activated gene of 3.5 and 8.5 kb were cloned from NIH3T3 secondary transfectants using a probe that detects the human alu family of highly repetitive DNA sequences. Repeat-free subclones of these BamHI fragments were used to map this gene to human chromosome 19 (p13.2-q13.3). Our studies also demonstrate that a subclone from one of the BamHI fragments detects a 3.0 kb transcript in primary and secondary transfectants.

The effects of twice and four times daily zidovudine on p24 antigenaemia in CDC stage II/III patients

Reduction of HIV p24 antigenaemia by zidovudine was investigated in 34 HIV antibody-positive, asymptomatic patients in a randomised, double-blind, placebo-controlled trial. Zidovudine was shown to lower p24 antigen levels as effectively when administered twice daily as when administered four times daily. Serum levels of p24 antigen varied little over 18 weeks in patients taking placebo.

Removing barriers to partnerships

One of the six corollaries to high quality healthcare identified in a 1987 study indicated that a team approach is required, although it challenges the notion of the professional autonomy of the medical staff. There are both individual and delivery system barriers to formation of partnerships and resistance to the change process. Combined with different views between physicians and executives, partnership building is a complicated process, and a number of recommendations are suggested to promote better relationships.

Genetic regions of Pseudomonas aureofaciens strain 211 involved in nopaline catabolism

A DNA fragment from the nopaline catabolism region of the Ti plasmid of Agrobacterium tumefaciens showed no detectable homology to the total DNA of several nopaline-utilizing strains of Pseudomonas spp. From one of these pseudomonads, Pseudomonas aureofaciens strain 211, mutants defective in the catabolism of nopaline but not arginine, have been obtained by mutagenesis with transposon Tn5, and also with TnV using a new suicide plasmid vector. The DNA fragment bearing the TnV insertion has been cloned and found to hybridize with DNA of every pseudomonad tested, independently of the capacity to utilize nopaline, but not with Agrobacterium DNA. In a separate experiment, nonmutagenized DNA of strain 211 was cloned in a cosmid vector. Transfer of one of these clones to Pseudomonas putida strain KT2440 conferred on the recipient the capacity for nopaline utilization. However, this cosmid clone was only partially functional, since it did not complement a TnV mutant.

Injuries of the spine sustained during rugby

In 1984 JR Silver reported on 63 patients who had sustained serious injuries of their cervical spine as a result of games of rugby between the years 1952 and 1982. In this paper his results have been brought up to date. A further 19 players who were treated personally are reported, sustaining their injuries between 1983 and 1987. The mechanism of injury was still blows to the head or the head being driven into the ground. Seven injuries occurred in the scrums all were front row forwards. One was injured when the players charged, two players were inexperienced and the other cases all followed a collapse of the scrum after which the second rows continued to push. Five players were injured while tackling, six players were injured in a ruck and maul situation--in each case they were pushed to the ground while stooping to pick up the ball, other players piled on top of them (one player broke from the scrum and he endeavoured to retrieve a low ball and then fell striking his head). Further research was carried out by circularising all the spinal units in the United Kingdom to obtain the overall figures. It has been found that there has been a reduction in the number of injuries from ten in 1983 to five in 1986/7, presumably from a change in the laws. In order to determine whether a further change in the laws was necessary or whether the existing laws were adequate, research was carried out by video recording several games of rugby and analysing the games later in slow motion and determining how injuries occurred. Most of the injuries in these small number of games occurred in the ruck and maul situation. It was concluded that the majority of such injuries were not due to bad luck but were caused by irresponsible actions. The laws were still being broken and not being enforced. The existing laws were adequate since there has been a reduction in the number of injuries overall, particularly at first class and schoolboy levels, but were not enforced at junior levels-they were the main source of injury.

Computer-directed stereotactic biopsy of intrinsic brain stem lesions

Despite advances in the neuro-imaging of the brain stem, an accurate diagnosis of intrinsic lesions in this region requires tissue sampling and histological verification. We have performed a series of computer-directed stereotactic procedures in 12 patients with intrinsic brain stem lesions. A positive diagnosis was obtained in 11 cases and therapeutic intervention was possible in four. There was no operative mortality. Because of the importance of an accurate diagnosis in order to avoid inappropriate therapy, together with the relative safety of the technique, computer-directed stereotactic biopsy should be considered in all patients harbouring an intrinsic brain stem mass.

Modulation of cytarabine metabolism in the human promyelocytic leukemia cell line HL-60 by polyhydroxy-substituted benzohydroxamic acids

Two potent new ribonucleotide reductase inhibitors, 3,4,5-trihydroxybenzohydroxamic acid (VF 122) and 3,4-dihydroxybenzohydroxamic acid (VF 147), were investigated for their ability to modulate the cellular pharmacology of cytarabine (ara-C) in HL-60 cells. VF 122 and VF 147 increased the total cellular uptake of ara-C by a mean (+/- SE) of 8% +/- 3% and 29% +/- 3%, respectively, when measured 2 hours after the start of exposure to 0.1 microM ara-C. This effect was evident after only 10 minutes of exposure to the riboNucleotide reductase inhibitor and did not vary significantly over the concentration range of 10-100 microM for either agent. VF 122 enhanced the incorporation of ara-CTP into DNA by 3.6-fold; VF 147 produced a 5.6-fold increase. In comparison, the maximum enhancement achievable with hydroxyurea was 2.1-fold, and with thymidine was 1.8-fold. These results provide a biochemical rationale for further investigation of these agents in combination with ara-C.

Nalidixic acid inhibits the conjugal transfer of conjugative N incompatibility group plasmids

The conjugal transfer of R plasmids of the N incompatibility group was inhibited by nalidixic acid to the same degree as that of plasmids of other conjugative and incompatibility groups. Inhibition was reversible. This supports a belief that nalidixic exerts its effect by interfering with a step(s) that is common to all conjugative systems among Enterobacteriaceae. These observations do not support an earlier suggestion that motivated the present study, and a reason for this is suggested.

Infective aneurysm of the left ventricle: angiographic and echocardiographic features

A 17-year-old man with staphylococcal endocarditis of the mitral valve developed an infective aneurysm of the posterior left ventricular wall. Echocardiography revealed an echo-free space posterior to the posterior left ventricular wall. This echo-free space undoubtedly represented the aneurysmal sac, because it could be temporarily obliterated by injecting saline into it and was no longer detectable following surgical closure of the sac. Thus echocardiography may be helpful in the detection of an infective aneurysm of the left ventricle.