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Biomedical subjects

C J Lawrence

Publications and source records attributed to C J Lawrence.

32 records · Page 2Linked to original sources

An investigation of the association of benzodiazepines and other hypnotics with the incidence of falls in the elderly.

Clinical and medication data from 2,878 admissions to a Department for Care of the Elderly were examined retrospectively to determine the association between the administration of hypnotics/benzodiazepines and the incidence of falls. Only lorazepam prescribed to females and nitrazepam prescribed to males were associated with a significantly increased incidence of falls. Women fell significantly more frequently than men, and 7.5% of falls resulted in fractures. Stroke was the most common major diagnosis in fall-cases, followed by infection, Parkinsonism and confusion.

Accidental Falls↗

The construction of biochemical reference ranges and the identification of possible adverse drug reactions in the elderly.

In the assessment of adverse drug reactions (ADRs) it is important to establish what is a normal range of values for a given biochemical measurement. Furthermore, such ranges need to be specific to the study population, for example, the elderly. A mixture of Gaussian distributions has been used in the construction of the reference ranges with maximum likelihood used to obtain estimates of the unknown parameters. With this approach, well-defined reference ranges have been established. Brief details are given of the numbers of ADRs identified in the study population using these ranges.

Aged↗

Isradipine, a calcium antagonist, in the control of hypertension following coronary artery-bypass surgery.

Arterial hypertension is common after coronary artery-bypass grafting (CABG) surgery and may lead to postoperative complications. Therefore, the effects of the calcium antagonist isradipine were studied in 10 postoperative CABG patients who had a mean arterial pressure (MAP) above 100 mm Hg. Isradipine, given as a continuous infusion, reduced MAP to the range of 85 +/- 5 mm Hg in all patients within 15 min. Systemic vascular resistance fell and cardiac output increased in all patients. A slight increase in heart rate was seen in some, but not all, patients. There were no adverse effects. In conclusion, isradipine appears to be a useful agent in the treatment of postoperative hypertension following CABG surgery.

Calcium Channel Blockers↗

Teenage sexual intercourse and pregnancy.

One hundred and one pregnant girls aged under 18 years were interviewed to collect information about the development of their sexual awareness, attitudes towards relationships, and about their social context. The data show that the girls were likely to come from homes where the parents were divorced, where the mother married when she was under 21 years of age, and where her first child was conceived out of wedlock. Altogether 76 of these pregnant girls first had intercourse before they were 16 years old. The younger the girl at first intercourse the sooner it occurred in the relationship and for almost half of the girls first intercourse was unplanned. Although almost half used contraception on the first occasion, only one third of the girls used contraceptives regularly. Most expressed the wish that they had delayed intercourse until they were older.

Adolescent↗

Statistical analysis of heart rates in subsequent victims of sudden infant death syndrome.

An analysis was made of heart rate records obtained prospectively from a group of full-term infants. The group consisted of 16 subsequent victims of sudden infant death syndrome (SIDS) and a set of 49 controls. The power spectra were calculated for each record and this together with the birth weight, gestational age and age at recording provided the basis for a discriminant analysis. The analysis identified a periodicity of 6-8 heart beats, in addition to the known effect of low birth weight, as associated with the risk of SIDS.

Biometry↗

Role of general practitioners in the care of disabled young adults.

Services for handicapped children end when these patients become young adults. In the Exeter Health Authority district 383 disabled young adults were interviewed about their unmet needs. Many wished for advice and counselling. A quarter had not visited their general practitioner in the previous year, and two thirds of these had not had a general assessment or seen a specialist.

Adult↗

A methodology for evaluating size at birth.

Data from the Swedish Medical Birth Registration, 1977-78, were utilized to develop methods of calculating reference standards for evaluating size at birth. Using the clinical information available, a 'healthy' sub-group was extracted. The individual distributions of birthweight (BW), birth length (BL) and birth headcircumference (BHc) at each week of gestational age (GA) were modelled following some truncation of their ranges. Application of the Box-Cox power family of transformations was generally found to improve the normality of the data. Certain percentages (such as 2.28, 50 and 97.72) were linked through a smoothing device. Features of the results include a positively skewed BW distribution in most GA weeks, a normal positively skewed BW distribution in most GA weeks, a normal distribution of BL and BHc at term, a larger relative variation in BW at lower GA than at term, and a distinct sigmoid shape of the median and other BW curves. Compared with five commonly quoted standards, the present data show the least deceleration in the fullterm region. Disregarding the clinical information, 'primary' sub-groups were also extracted using decomposing techniques. These gave rise to similar BW/GA relationships. Using data from the WHO comparative study, the method just mentioned was applied to standardize BW and BW-specific early neonatal mortality rates. This resulted in an improved description of biological events.

Birth Weight↗

Factors associated with delayed onset of regular respiration.

In a population of 16333 singleton births born in one week of April, 1970, 4.4% failed to establish regular respiration within 3 min of birth. A follow-up at 5 years of age collected medical, educational and sociological information on 79.6% of the survivors of the cohort identified by the birth survey. Data have been analysed to investigate the relationships between the delay in the onset of regular respiration and possible risk factors identifiable prior to or at the time of birth. Complex statistical analysis employing linear modelling techniques showed that the delay in the onset of respiration was primarily related to: null and high parity; antepartum haemorrhage (especially placenta praevia); pre-eclampsia; breech delivery; Caesarian section and low birthweight. There was no association with maternal smoking during pregnancy or with social class. These conclusions are reasonably consistent with those drawn from other studies using alternative measures of asphyxia.

Child, Preschool↗

Delayed onset of regular respiration and subsequent development.

A comprehensive survey carried out at birth, data on mortality and a 5 year follow-up covering medical, educational and sociological aspects of child development were available for singleton births born in one week of April 1970. The survey at 5 years of age included 12363 children, 79.6% of the surviving cohort. An assessment has been made of the extent to which delay in the onset of regular respiration at birth is associated with the subsequent development of the child. Using the results of our previous investigations, the relationships between this delay and other factors known at the time of birth have been taken into account. The distributions of a large number of development variables were not significantly different for groups of children determined by respiratory delay at birth, but there was an association with mortality and cerebral palsy. In addition, there was an unexpected relationship between delayed onset of respiration and subsequent bronchitis. This association remained significant after controlling for possible confounding effects using linear modelling techniques.

Bronchitis↗

Epidemic influenza in Greater London.

The Kermack & McKendrick theory of epidemics has been applied to data on deaths from influenza and influenzal pneumonia in Greater London in the years 1950-78. As a whole the theory gives a good description of the data, and the estimated values of the parameters can be plausibly related to the natural history of the disease. However, the possibility exists that the agreement is merely empirical, and field studies would be required to confirm its validity.

Disease Outbreaks↗

Plus ça change: predictors of birthweight in two national studies.

The 16 989 singleton births in one week of March, 1958, studied by the British Perinatal Mortality Survey, were subjected to an analysis of covariance, which showed that major factors associated with birthweight of the infant were: maternal height, history of smoking in pregnancy, parity and history of pre-eclampsia during the pregnancy. The same analysis was repeated on the data collected on 16792 singletons born 12 years later in one week of April, 1970 and studied by the British Births Survey. In spite of major changes in obstetric practice and in the maternal population, the same factors were shown to be highly significant and the magnitude of the associations had changed little.

Analysis of Variance↗

Hypereosinophilic syndrome with biventricular involvement.

In a 45-year-old man with hypereosinophilic syndrome, cardiac disease, mainly endocardial thickening and extensive mural thrombosis of both ventricles, was confirmed at autopsy. Early in the course of the disease, right ventricular endocardial biopsy had demonstrated the basic process. Restriction in filling and contraction of the right ventricle were demonstrated by functional studies. By echocardiographic study, progressive reduction in size of the right ventricular cavity and premature opening of the pulmonary valve were demonstrated, while this method was less adequate in identifying the process in the left ventricle.

Autopsy↗

Myocardial infarction: a comparison between home and hospital care for patients.

To compare the results of home and hospital treatment in men aged under 70 years who had suffered acute myocardial infarction within 48 hours 1895 patients were considered for study in four centres in south-west England. Four-hundred-and-fifty patients were randomly allocated to receive care either at home by their family doctor or in hospital, initially in an intensive care unit. The randomised treatment groups were similar in age, history of cardiovascular disease, and incidence of hypotension when first examined. They were followed up for up to a year after onset. The mortality rate at 28 days was 12% for the random home group and 14% for the random hospital group; the corresponding figures at 330 days were 20% and 27%. On average, older patients and those without initial hypotension fared rather better under home care. The patients who underwent randomisation were similar to those whose place of care was not randomised, except that the non-randomised group contained a higher proportion of initially hypotensive patients, whose prognosis was poor wherever treated. These results confirm and extend our preliminary findings. Home care is a proper form of treatment for many patients with acute myocardial infarction, particularly those over 60 years and those with an uncomplicated attack seen by general practitioners.

Adult↗