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Biomedical subjects

N Wald

Publications and source records attributed to N Wald.

At least 109 records · Page 6Linked to original sources
PubMed1980

Small biparietal diameter of fetuses with spina bifida: implications for antenatal screening.

The biparietal diameter of 20 fetuses with spina bifida was measured during pregnancy by ultrasound scanning, mainly in the second trimester. The mean result was 0.83 cm smaller than the value based on 186 unaffected pregnancies at the same gestational ages (P less than 0.001), suggesting that spina bifida fetuses are growth retarded. The practical consequence of this finding is that the routine use of ultrasound in pregnancy will increase the sensitivity of AFP screening for open spina bifida at 16 to 18 weeks gestation from 79 per cent as estimated by the UK Collaborative AFP Study to about 90 per cent or more.

Cephalometry↗
PubMed1980

Survival and handicap of infants with spina bifida.

A follow-up study was carried out on 213 infants born with spina bifida cystica (including encephalocele and occipital meningocele) from 1965 to 1972 to women resident in Oxfordshire and the western part of Berkshire. The 5-year survival rate was 36% (39/107) for those with open lesions, 60% (30/50) for those with closed ones, and 18% (10/56) for those with lesions which could not be classified (not known) but which were probably nearly all open. The extent of handicap among these survivors was assessed by means of criteria described by Lorber; among those with open lesions (including 'not known') 84% (41/49) were severely handicapped, 10% (4/49) were moderately handicapped, and only 6% (3/49) had no handicap; among those with closed lesions, 37% (11/30) were severely handicapped, 33% (10/30) were moderately handicapped, and the remaining 30% (9/30) were not handicapped. Closed head lesions (encephalocele or occipital meningocele) were more often associated with severe handicap (6/8; 75%) than were closed spinal lesions (5/22; 23%). The children with open lesions who survived for at least 5 years spent, on average, at least 6 months in hospital during the first 5 years of their life and had, on average, at least 6 major surgical operations. In comparison, those with closed lesions spent one-third less time in hospital, and had fewer than half as many operations. During the period of the study a selective treatment policy was adopted typical of that commonly practised now, and all the infants were born before antenatal screening had been introduced. Our results therefore may be helpful in assessing the benefits to be expected from antenatal screening for open spina bifida.

Encephalocele↗
PubMed1979

Randomised trial of two-drug and four-drug maintenance chemotherapy in advanced or recurrent Hodgkin's disease. Medical Research Council's working party on lymphomas.

Between 1970 and 1975, 108 patients who presented with advanced or recurrent Hodgkin's disease and were free of disease after six courses of chemotherapy with mustine, vinblastine, procarbazine, and prednisone (MVPP) were allocated at random to one of two regiments of maintenance treatment: either intermittent treatment with vinblastine and procarbazine or intermittent treatment with MVPP. After a median follow-up period of nearly five years there was no significant difference between the two groups in either the rate of relapse or death rate. Six of the 55 patients given the two-drug regimen died compared with 10 of the 53 given the four-drug regimen. The four-drug required hospital attendance and was less agreeable than the two-drug regimen. The efficacy of maintenance chemotherapy with the two-drug regimen was no less than that with the four-drug regimen, but the two-drug regimen had several practical advantages.

Adult↗
PubMed1978

Maternal serum alpha-fetoprotein levels in triplet and quadruplet pregnancy.

Maternal serum alpha-fetoprotein (AFP) levels were higher in six triplet pregnancies and three quadruplet pregnancies than in control singleton pregnancies matched for maternal age, parity and time of gestation at which the serum sample was taken. Between 12 and 23 weeks of pregnancy, the average AFP levels among the triplet pregnancies was three times that found in the singleton pregnancies, and the level in the quadruplet pregnancies was even higher. Maternal serum AFP levels appear to be associated with the number of fetuses in utero.

Female↗
PubMed1978

Carboxyhaemoglobin levels and inhaling habits in cigarette smokers.

In 520 men who currently smoked only cigarettes, carboxyhaemoglobin (COHb) levels were measured as a method of estimating the extent to which cigarette smoke was inhaled and the results were compared with the smokers' own assessment of their inhaling habits. The mean COHb level after standardising for the number of cigarettes smoked before the blood test on the day of the test was 4.0% in self-described non-inhalers. This was much higher than the mean level of 0.7% in 1891 similar non-smokers, but not very different from the standardised mean levels of 5.2%, 5.3%, and 5.6% in men who said they inhaled slightly, moderately, or deeply, respectively. The increasing trend in the COHb levels of men in the four self-described inhaling categories (nil to deep) was small but statistically highly significant. The data from this study may help to explain some of the anomalous epidemiological results regarding the relationship between self-described inhaling habits and the development of diseases associated with smoking, such as coronary heart disease and lung cancer.

Adult↗
PubMed1977

Maternal serum-alpha-fetoprotein and low birth-weight.

High maternal serum-alpha-fetoprotein (A.F.P.) concentrations in the first half of pregnancy were associated with prematurity and high perinatal mortality. 94 singleton pregnancies without neural-tube defects but with A.F.P. levels equal to or greater than three times the normal median resulted in the birth of infants weighing, on average, 357 g less than controls (P less than 0-001). The mean head circumference of the infants was also smaller than that of the controls. The 1 stillbirth and 3 neonatal deaths yielded a mortality-rate more than three and a half times that for singleton births without neural-tube defects at the same hospital in the years 1974-76. The results suggest that some pregnant women who will deliver low-birth-weight infants at high risk of perinatal death may be identified by means of serum-A.F.P. measurement early in pregnancy.

Abortion, Spontaneous↗
PubMed1977

Carboxyhaemoglobin levels in smokers of filter and plain cigarettes.

Blood-carboxyhaemoglobin (COHb) levels were studied in 343 healthy male cigarette smokers aged 35-64. The mean COHb level was 30% higher in the 248 men who smoked unventilated filter cigarettes than in the 41 men who smoked plain cigarettes, after adjusting for the number of cigarettes smoked (P less than 0.001). This result was consistent with the carbon-monoxide (CO) yields of these cigarettes: on average, the unventilated filter cigarettes had yields 25% higher than the plain ones. The mean COHb level was 7% higher in the 54 men who smoked ventilated cigarettes than in men who smoked plain cigarettes. Although this difference was not statistically significant, it was in the opposite direction to the result which might have been expected on the basis of the CO yields of these cigarettes: on average the ventilated filter cigarettes had yields 21% lower than the plain ones. The medical implications of these results are uncertain. COHb levels of 3-4% or more can exacerbate angina pectoris and intermittent claudication, and it is, therefore, of concern that COHb levels are higher in smokers of filter cigarettes than in smokers of plain cigarettes. However, any assessment of risk associated with either type of cigarette should take account of the observation from other studies that filter cigarettes are associated with a lower mortality from lung cancer than are plain cigarettes.

Adult↗
PubMed1977

Maternal serum alpha-fetoprotein and spontaneous abortion.

The relationship between spontaneous abortion and maternal serum alpha-fetoprotein (AFP) levels was investigated between 9 and 25 weeks of pregnancy. Seven out of 126 (5-6 per cent) women who had spontaneous abortions had raised maternal serum AFP levels at their antenatal booking visit compared to 4 out of 247 (1-6 per cent) control patients who were delivered of single liveborn infants, a statistically significant differences. The raised AFP concentrations were, however, associated with spontaneous abortion only if the serum samples had been taken immediately before, or at sometime after the abortion was first clinically suspected. This suggests that high levels do not predict the development of abortion in women who have not already threatened to abort. It is therefore unlikely that women who have not already threatened to abort. Therefore, when maternal serum AFP levels are used to screen for fetal neural tube defects, women referred for a diagnostic amniocentesis on account of a high level are unlikely to have been selected on the basis of a tendency to abort.

Abortion, Spontaneous↗
PubMed1976

The selection of virus-resistant Chinese hamster ovary cells.

We have selected Chinese hamster ovary (CHO) cells resistant to infection by encephalomycarditis (EMC) virus. Thus far, we have obtained five lines resistant to EMC, all of which manifest different phenotypes. Three of the five are not persistently infected with virus, while two lines produce infectious virus and grow in its presence. The nonpersistently infected lines exhibit different resistance profiles to the other viruses we have tested, and they are stable in nonselective growth conditions. Their resistance appears to be due to a genetic alteration in the cell.

Cell Division↗
PubMed1976

Maternal serum alpha-fetoprotein and previous neural tube defects.

A case-control study involving 63 pregnancies showed that women who had previously had an infant with anencephaly or spina bifida did not have raised serum alpha-fetroprotein (AFP) levels in subsequent unaffected pregnancies. The value of a serum AFP determination in such women is discussed. If the serum AFP level is normal and if ultrasonography excludes anencephaly the risk of spina bifida might be low enough (about 1 per cent) to make diagnostic amniocentesis difficult to justify. Conversely, a high serum AFP value in such women should not be acted on without confirmation of an abnormality by ultrasonography and, if that is negative, by diagnostic amniocentesis.

Amniocentesis↗