MRC trial of treatment of mild hypertension: principal results. Medical Research Council Working Party.

The main aim of the trial was to determine whether drug treatment of mild hypertension (phase V diastolic pressure 90-109 mm Hg) reduced the rates of stroke, of death due to hypertension, and of coronary events in men and women aged 35-64 years. Subsidiary aims were: to compare the course of blood pressure in two groups, one taking bendrofluazide and one taking propranolol, and to compare the incidence of suspected adverse reactions to these two drugs. The study was single blind and based almost entirely in general practices; 17 354 patients were recruited, and 85 572 patient years of observation have accrued. Patients were randomly allocated at entry to take bendrofluazide or propranolol or placebo tablets. The primary results were as follows. The stroke rate was reduced on active treatment: 60 strokes occurred in the treated group and 109 in the placebo group, giving rates of 1.4 and 2.6 per 1000 patient years of observation respectively (p less than 0.01 on sequential analysis). Treatment made no difference, however, to the overall rates of coronary events: 222 events occurred on active treatment and 234 in the placebo group (5.2 and 5.5 per 1000 patient years respectively). The incidence of all cardiovascular events was reduced on active treatment: 286 events occurred in the treated group and 352 in the placebo group, giving rates of 6.7 and 8.2 per 1000 patient years respectively (p less than 0.05 on sequential analysis). For mortality from all causes treatment made no difference to the rates. There were 248 deaths in the treated group and 253 in the placebo group (rates 5.8 and 5.9 per 1000 patient years respectively). Several post hoc analyses of subgroup results were also performed but they require very cautious interpretation. The all cause mortality was reduced in men on active treatment (157 deaths versus 181 in the placebo group; 7.1 and 8.2 per 1000 patient years respectively) but increased in women on active treatment (91 deaths versus 72; 4.4 and 3.5 per 1000 patient years respectively). The difference between the sexes in their response to treatment was significant (p = 0.05). Comparison of the two active drugs showed that the reduction in stroke rate on bendrofluazide was greater than that on propranolol (p = 0.002). The stroke rate was reduced in both smokers and non-smokers taking bendrofluazide but only in non-smokers taking propranolol. This difference between the responses to the two drugs was significant (p = 0.03).(ABSTRACT TRUNCATED AT 400 WORDS)     

Phenylketonuria in U.S. blacks: molecular analysis of the phenylalanine hydroxylase gene

We investigated the frequency, origin, and molecular basis of phenylketonuria (PKU) in U.S. blacks. On the basis of 10 years of Maryland newborn-screening data, we found the frequency to be 1/50,000, or one-third that in whites. We performed haplotype analysis of the phenylalanine hydroxylase (PAH) gene of 36 U.S. blacks, 16 from individuals with classical PKU and 20 from controls. In blacks, 20% of wild-type PAH alleles have a common Caucasian haplotype (i.e., haplotype 1), whereas 80% had a variety of haplotypes, all rare in Caucasians and Asians. One of these, haplotype 15, accounted for a large fraction (30%). Among black mutant PAH alleles, 20% have a haplotype (i.e., either haplotype 1 or haplotype 4) common in Caucasians; 40% have a haplotype rare in Caucasians and Asians, and 40% have one of two previously undescribed haplotypes. Both can be derived from known haplotypes by a single event. One of these haplotypes is characterized by a new MspI restriction site, located in intron 8, which was present in five of 16 black mutant alleles but was not present in 60 U.S. black control, 20 U.S. Caucasian control, or 20 Caucasian mutant PAH alleles. Sequence analysis of DNA from a single individual, homozygous for the new MspI associated haplotype, shows homozygosity for a C----T transition at nucleotide 896 in exon 7 of the PAH cDNA, resulting in the conversion of leucine 255 to serine (L255S).     

Medical Research Council trial of treatment of hypertension in older adults: principal results. MRC Working Party.

To establish whether treatment with diuretic or beta blocker in hypertensive older adults reduces risk of stroke, coronary heart disease, and death.Randomised, placebo controlled, single blind trial.226 general practices in the MRC general practice research framework.4396 patients aged 65-74 randomised to receive diuretic, beta blocker, or placebo. Patients had mean systolic pressures of 160-209 mm Hg and mean diastolic pressures less than 115 mm Hg during an eight week run in and were not taking antihypertensive treatment.Patients were randomised to atenolol 50 mg daily; hydrochlorothiazide 25 mg or 50 mg plus amiloride 2.5 mg or 5 mg daily; or placebo. The regimens were adjusted to achieve specified target pressures. Mean follow up was 5.8 years.Strokes, coronary events, and deaths from all causes.Both treatments reduced blood pressure below the level in the placebo group. Compared with the placebo group, actively treated subjects (diuretic and beta blocker groups combined) had a 25% (95% confidence interval 3% to 42%) reduction in stroke (p = 0.04), 19% (-2% to 36%) reduction in coronary events (p = 0.08), and 17% (2% to 29%) reduction in all cardiovascular events (p = 0.03). After adjusting for baseline characteristics the diuretic group had significantly reduced risks of stroke (31% (3% to 51%) p = 0.04), coronary events (44% (21% to 60%), p = 0.0009), and all cardiovascular events (35% (17% to 49%), p = 0.0005) compared with the placebo group. The beta blocker group showed no significant reductions in these end points. The reduction in strokes was mainly in non-smokers taking the diuretic.Hydrochlorothiazide and amiloride reduce the risk of stroke, coronary events, and all cardiovascular events in older hypertensive adults.     

Bleomycin in advanced squamous cell carcinoma: a random controlled trial. Report of Medical Research Council Working Party on Bleomycin.

Bleomycin was compared with conventional cytotoxic drugs in the treatment of 70 patients with advanced squamous cell carcinoma; the primary deposit was in the head and neck in 50 patients and in the perineum or skin in 20. Thirty-four patients received bleomycin while 36 received other cytotoxic drugs. No significant difference was detected between the two groups either in the proportion showing tumour regression or in the survival rates. If bleomycin is to advance the treatment of squamous cell carcinoma it can be only in combination with other drugs or with radiotherapy.     

The mechanism of the irreversible inhibition ofrat liver phenylalanine hydroxylase due to treatment with p-chlorophenylalanine. The lack of effect on turnover of phenylalanine hydroxylase.

The administration of a single dose of p-chlorophenylalanine (360 mg/kg) to rats leads to the irreversible loss of 90% of hepatic phenylalanine hydroxylase activity after 24 h. This loss of activity is not the result of either an alteration in the overall structure of the enzyme, as determined by its antigenicity, or in the total immunologically reactive protein in the liver, as tested with a specific antiserum prepared against native phenylalanine hydroxylase. Neither the rate of synthesis nor the rate of degradation of phenylalanine hydroxylase is changed by p-chlorophenylalanine (pClPhe) treatment. The half-life for the enzyme is about 2 days in control and in pClPhe-treated rats. In addition, there is no detectable incorporation of pClPhe into the phenylalanine hydroxylase molecule itself.     

Randomised controlled trial of treatment for mild hypertension: design and pilot trial. Report of Medical Research Council Working Party on Mild to Moderate Hypertension.

A multicentre pilot trial to assess the feasibility of undertaking a full-scale national trial of treatment for mild to moderate hypertension has been performed and is being continued. By February 1977 over 1800 patients had entered the trial and some have been under observation for three years. The results so far show that the definitive trial is administratively and scientifically feasible and ethically justified.     

Course of blood pressure in mild hypertensives after withdrawal of long term antihypertensive treatment. Medical Research Council Working Party on Mild Hypertension.

A series of 1418 men and 1,347 women with mild hypertension (diastolic phase V 90-109 mm Hg) aged 35-64 who had either had long term antihypertensive treatment with bendrofluazide or propranolol or taken placebo tablets for a similar period were randomly allocated to groups in which their tablets were either stopped or continued. The course of blood pressure and of biochemical variables was followed up for two years. Mean blood pressures rose rapidly after the withdrawal of active treatment, and between nine months and one year after stopping treatment the antihypertensive effect had almost disappeared. The effect persisting longer than this, and possibly due to resetting of the baroreceptors or of other blood pressure control mechanisms, was very small, and as the rise in mean pressure was due to an upward movement in general distribution there was no evidence of a subgroup in whom these mechanisms had been permanently reset to a clinically important extent. After withdrawal of propranolol the rise in pressure was more rapid in younger than in older people. After stopping bendrofluazide pressure rose more rapidly in men who had had higher pressures before and during treatment; this effect was not seen in women. Disturbances in biochemical variables associated with drug treatment had largely resolved by the end of two years after withdrawal. Stopping placebo tablets made no consistent difference to blood pressure.     

Analysis of treatment in childhood leukaemia. I. Predisposition to methotrexate-induced neutropenia after craniospinal irradiation. Report to the Medical Research Council of the Working Party on Leukaemia in Childhood.

The degree of drug-induced neutropenia resulting from a controlled trial (UKALL I) of treatment in acute lymphoblastic leukaemia was analysed. The main agent associated with severe neutropenia was methotrexate, and methotrexate-induced neutropenia was significantly greater in patients who had received craniospinal irradiation. The synergistic toxic effect of irradiation followed by methotrexate treatment seems to have contributed to three of the five deaths which occurred in complete remission in this trial; all deaths in remission occurred in patients who had received central nervous system prophylaxis. Analysis of patients who subsequently relapsed compared with those still in remission after 18 months of treatment indicated that the former, on average, had slightly lower neutrophil counts. This suggests that the children who relapsed did not receive any less aggressive treatment than those who remained in remission.     

Treatment of acute lymphoblastic leukaemia: effect of variation in length of treatment on duration of remission. Report to the Medical Research Council by the Working Party on Leukaemia in Childhood.

Patients with acute lymphoblastic leukaemia (ALL) were allocated at random either to stop maintenance chemotherapy after six 12-week courses or continue with a further six. The main difference between the two groups was in the incidence of bone-marrow relapse within nine months after stopping treatment. Such relapses occurred less in older patients and those with higher leucocyte counts initially than in those who appeared to have the best prognosis--namely, those with typical low-count childhood ALL. No patient given prophylactic irradiation to cranium and spine combined with intrathecal methotrexate suffered meningeal relapses, whereas among those not given such prophylaxis the lack of benefit from continuing treatment was mainly attributable to meningeal relapses.     

Molecular genetics of phenylketonuria in Mediterranean countries: a mutation associated with partial phenylalanine hydroxylase deficiency.

We report the characterization of a mutation in the phenylalanine hydroxylase (PAH) gene associated with partial residual activity of the enzyme. This point mutation (280glu----lys) was found by sequencing a mutant cDNA clone derived from a needle biopsy of the liver in a child with variant form of phenylketonuria. There is a strict concordance between homozygosity for the mutation and this particular phenotype. The (280glu----lys) mutation is linked to an original and rare RFLP haplotype at the PAH locus found in south Europe and North Africa. So far, this genotype-haplotype association is both inclusive and exclusive. Thirty-three PAH-deficient patients were screened for the mutation by using polymerase chain-reaction amplification of their genomic DNA extracted from Guthrie cards. Since a large number of patients can be screened for a particular mutation by using Guthrie cards, the possibility arises of using these samples collected by national newborn screening centers for prospective and retrospective detection of other mutations in the human genome.     

Adult advanced cardiac life support: the European Resuscitation Council guidelines 1992 (abridged). European Resuscitation Council Working Party.

The European Resuscitation Council, established in 1990, is committed to saving lives by improving standards of cardiopulmonary resuscitation across Europe and coordinating the activities of interested organisations and individuals. In this regard the council has successfully brought together physicians and surgeons from eastern and western Europe and, in addition, has established relations with the American Heart Association and equivalent organisations in Canada, Australia, and South Africa. A main objective of the European Resuscitation Council is to produce guidelines for cardiopulmonary and cerebral resuscitation, and in this paper members of a working party of 14 experts from 11 countries set out an abridged version of the council''s guidelines for adult advanced cardiac life support. The council hopes that the guidelines and accompanying algorithms will serve as a ready use "how to do it" for ordinary practitioners and paramedics inside and outside hospital.     

Effects of varying radiation schedule,cyclophosphamide treatment,and duration of treatment in acute lymphoblastic leukaemia. Report to the Medical Research Council by the Working Party on Leukaemia in Childhood.

In a multicentre trial of treatment for acute lymphoblastic leukaemia the effects of three types of central nervous system prophylaxis, the inclusion of cyclophosphamide, and the total duration of chemotherapy were assessed. A schedule with a high dose of spinal irradiation (2400 rads) without intrathecal methotrexate was inferior to schedules with some (1000 rads) or no spinal irradiation but with intrathecal methotrexate. The addition of cyclophosphamide 600 mg/m2 given intravenously every 12 weeks was of no benefit and was possibly deleterious. There was no advantage in adding four 12-week courses of chemotherapy after eight courses (total duration two years) had been given. Girls fared significantly better than boys, the difference being only partly due to the occurrence of testicular relapse.     

A novel two-dimensional polyacrylamide-gel pattern, which may be due to allelic genes, of phenylalanine hydroxylase in monkeys.

Two-dimensional gel electrophoresis of immunopurified monkey liver phenylalanine hydroxylase showed a novel form of the enzyme, in 4 out of 24 monkeys, in which each polypeptide spot was split into a doublet with the same charge but slightly different mobility in the sodium dodecyl sulphate/polyacrylamide-gel-electrophoresis (as opposed to the isoelectric-focusing) dimension. Phenylalanine hydroxylase formed by translation of RNA from a liver containing the novel form showed the doublet pattern, suggesting that it is due to differences in mRNA. By analogy with the rat, this mRNA difference could be due to allelic genes.