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Biomedical subjects

A Lawson

Publications and source records attributed to A Lawson.

At least 37 records · Page 2Linked to original sources
PubMed1997

Audit of ascertainment of deaths to children born in Cumbria, UK, 1950-89 through the NHS central register.

STUDY OBJECTIVE: To evaluate the completeness of notification of deaths by the National Health Service Central Register (NHSCR) for England and Wales. DESIGN: Deaths for a birth cohort were ascertained through scanning the relevant volumes of NHSCR. Attempts were made to confirm these deaths and additional deaths were ascertained through searching local records. Logistic regression was used to investigate how the probability of a death being missed by NHSCR varied with the year of birth, age at death, sex, and social class. SETTING: Deaths up to the end of 1989 in the CA postal area among 264,046 children born between 1950 and 1989 to mothers living in Cumbria. RESULTS: NHSCR originally ascertained 4139 deaths; local searches confirmed 3338 (81%) of these and found an additional 342. Most deaths missed by the NHSCR were neonatal deaths in the 1950s and 1960s. In the 1950s, 31% of children who died in the neonatal period either were not entered on NHSCR or, if they were entered, there was no record of their death. For children born from 1970 onwards, ascertainment of deaths through NHSCR was over 99% complete. CONCLUSIONS: The NHSCR was started in 1948 for the administration of records of National Health Service patients. It seems that many babies who died soon after birth were not therefore recorded. In parallel with the increasing use of NHSCR for epidemiological purposes, there has been a substantial and continuing improvement in its clerical procedures since the mid 1960's.

Cause of Death↗
PubMed1997

Interexaminer agreement for applied kinesiology manual muscle testing.

Two trials of the interexaminer reliability of Applied Kinesiology manual testing were conducted. On the first trial three clinicians, each with greater than ten years of experience with muscle testing procedures, tested 32 healthy individuals to estimate their agreement on the strength or weakness of right and left piriformis and right and left hamstring muscles. Significant agreement between examiners was found for piriformis muscles, but little significant agreement was noted when hamstrings were tested. In a second study, the same three examiners tested 53 subjects for strength or weakness of the pectoralis and tensor fascia lata muscles bilaterally. Significant interjudge agreement was found for pectoralis muscles, but no significant concordance could be found when the tensor fascia lata was examined.

Fascia Lata↗
PubMed1996

Randomised placebo controlled trial of effect on mood of lowering cholesterol concentration. Oxford Cholesterol Study Group.

OBJECTIVE: To evaluate the effects on mood of a substantial and prolonged reduction in total cholesterol concentration. DESIGN: Randomised placebo controlled comparison of patients who had been allocated to receive simvastatin 20 mg or 40 mg daily versus those allocated matching placebo in a ratio of 2:1. Follow up at an average of 152 weeks after randomisation. SUBJECTS: Men and women aged between 40 and 75 years at entry with blood total cholesterol of 3.5 mmol/l or greater, who were considered to be at higher than average risk of coronary heart disease based on medical history. MAIN OUTCOME MEASURES: The shortened profile of mood states questionnaire, reported use of psychotropic medication, and symptoms possibly related to mood. RESULTS: Simvastatin reduced total cholesterol by 1.9 mmol/l (26.7%) at the time of follow up. Among all 621 patients randomised to simvastatin (414 patients) or placebo (207 patients) there were no significant differences in the use of psychotropic medication or in reports of symptoms possibly related to mood. Of these patients, 491 (334 simvastatin, 157 placebo) completed the mood questionnaire, and there were no significant differences between the treatment groups in total or subscale scores, even when patients with low baseline cholesterol concentrations or elderly subjects were considered separately. CONCLUSION: These results do not support the hypothesis that treatment to lower cholesterol concentration causes mood disturbance.

Adult↗
PubMed1996

Co-expression of human protein disulphide isomerase (PDI) can increase the yield of an antibody Fab' fragment expressed in Escherichia coli.

Secretion to the periplasm of Escherichia coli enables production of many eukaryotic extracellular proteins in a soluble form. The complex disulphide bond arrangement of such proteins is probably a major factor in determining the low yield of correctly folded product observed in many cases. Here we show that co-expression of human protein disulphide isomerase increased the yield of a monoclonal antibody Fab' fragment in the periplasm of E. coli.

Amino Acid Sequence↗
PubMed1996

The effect of embryonic cerebrospinal fluid pressure and morphogenetic brain expansion on wound healing in the midbrain of the chick embryo.

The role of increased cerebrospinal fluid pressure and morphogenetic brain expansion on midbrain wound healing was studied in chick embryos at stages 16-22. The embryos were divided into six groups as follows: group I (stages 16/17), group II (stages 18/19), group III (stages 20-22), group IV (stages 18/19), group V (stages 20-22) and group VI (stages 18/19). The mid-brains of embryos of groups I-III were wounded and the embryos re-incubated for varying periods up to 24 h. The neuroepithelial wounds of all group-I embryos healed completely within 24 h. However, complete healing was observed in only 25% of wounds in group II and 11.4% in group III by 24 h. To reduce cerebrospinal fluid pressure and thus slow down brain expansion, longitudinal wounds (about 0.8 mm long) were made in the hindbrain roof plate of group-IV and group-V embryos, and puncture wounds (0.1 mm in diameter) also in the hindbrain roof plate of group-VI embryos. This allowed cerebrospinal fluid to escape prior to wounding the midbrain. There was a significant increase in the proportion of group-IV and group-V embryos with completely healed midbrain neuroepithelial wounds (77.3% and 28.6% respectively). However, a comparison between groups II and VI embryos yielded no statistically significant difference in healing. Thus, increasing cerebrospinal fluid pressure and brain expansion adversely affect midbrain neuroepithelial wound healing.

Animals↗
PubMed1996

Absence of effects of prolonged simvastatin therapy on nocturnal sleep in a large randomized placebo-controlled study. Oxford Cholesterol Study Group.

1. It has been suggested that lipophilic HMG CoA reductase inhibitors, like lovastatin and simvastatin, may cause sleep disturbance. 2. Six hundred and twenty-one patients at increased risk of coronary heart disease were randomized in a single centre to receive 40 mg daily simvastatin, 20 mg daily simvastatin or matching placebo. To assess the effects of prolonged use of simvastatin on nocturnal sleep quality and duration, a sleep questionnaire was administered to 567 patients (95% of 595 survivors) at an average of 88 weeks (range: 44-129 weeks) after randomization. 3. The main outcome measures were sleep-related problems and use of sleep-enhancing medications reported during routine study follow-up visits, and responses to the sleep questionnaire about changes in sleep duration and about various sleep events during the preceding month. 4. No differences were observed between the treatment groups in the frequency of sleep-related problems reported, in the proportion of follow-up visits at which such problems were reported, or in the use of sleep-enhancing medications. The numbers who stopped study treatment were similar in the different treatment groups, and no patient stopped principally because of insomnia. In response to the sleep questionnaire, there were no significant differences between the treatment groups in reports of various sleep events during the preceding month, except that slightly fewer patients allocated simvastatin reported waking often. No differences in sleep duration were observed. 5. This placebo-controlled trial does not indicate any adverse effects of prolonged treatment with simvastatin on systematically sought measures of sleep disturbance.

Adult↗
PubMed1994

Three-year follow-up of the Oxford Cholesterol Study: assessment of the efficacy and safety of simvastatin in preparation for a large mortality study.

We report the results of a randomized single-centre study designed to assess the effects of simvastatin on blood lipids, blood biochemistry, haematology and other measures of safety and tolerability in preparation for a large-scale multicentre mortality study. Six hundred and twenty-one individuals considered to be at increased risk of coronary heart disease were randomized, following a 2-month placebo 'run-in' period, to receive 40 mg daily simvastatin, 20 mg daily simvastatin or matching placebo. Their mean age was 63 years, 85% were male, 62% had a history of prior myocardial infarction (MI), and the mean baseline total cholesterol was 7.0 mmol.l-1. Median follow-up in the present report is 3.4 years. Eight weeks after randomization, 40 mg daily simvastatin had reduced non-fasting total cholesterol by 29.2% +/- 1.1 (2.03 +/- 0.08 mmol.l-1) and 20 mg daily simvastatin had reduced it by 26.8% +/- 1.0 (1.87 +/- 0.07 mmol.l-1). Almost all of the difference in total cholesterol at 8 weeks was due to the reduction in LDL cholesterol (40.8% +/- 1.6 and 38.2% +/- 1.4 among patients allocated 40 mg and 20 mg of simvastatin daily respectively), but simvastatin also reduced triglycerides substantially (19.0% and 17.3%) and produced a small increase in HDL cholesterol (6.4% and 4.8%). These effects were largely sustained over the next 3 years, with 40 mg daily simvastatin producing a slightly greater reduction in total cholesterol at 3 years (25.7% +/- 1.9 reduction) than did 20 mg daily simvastatin (22.2% +/- 1.8). There were no differences between the treatment groups in the numbers of reports of 'possible adverse effects' of treatment or of a range of different symptoms or conditions (including those related to sleep or mood) recorded at regular clinic follow-up. Mean levels of alanine aminotransferase, aspartate aminotransferase and creatine kinase were slightly increased by treatment, but there were no significant differences between the treatment groups in the numbers of patients with significantly elevated levels. A slightly lower platelet count in the simvastatin group was the only haematological difference from placebo, with no difference in the numbers of patients with low platelet counts. In summary, the simvastatin regimens studied produced large sustained reductions in total cholesterol, LDL cholesterol and triglyceride and small increases in HDL cholesterol. They were well tolerated, with no evidence of serious side-effects during the first 3 years of this study.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Respiratory abnormalities in infants of substance-abusing mothers: role of prematurity.

It is a current hypothesis that maternal history of drug addiction during pregnancy and detection of drugs in the urine of the newborn are associated with increased incidence of apnea. To test this hypothesis, we reviewed polygraphic studies of respiration in two groups of infants who had been exposed in utero to cocaine (and other drugs). The first group was composed of 20 term infants (39.1 +/- 0.8 weeks gestation), and premature infants (35.4 +/- 0.8 weeks gestation). None of the infants were on methylxanthines. These infants were matched with 15 term and 15 preterm infants of similar gestational age. Variables studied were: heart rate, respiration, chest impedance pneumography, nasal airflow and oxygen saturation (pulse oximetry). Apnea indices for central and obstructive events of short and long duration as well as periodic breathing and oxygen saturation were obtained. Term drug-exposed infants had less central apnea and a higher rate of periodic breathing compared to term controls, whereas drug-exposed premature infants had more obstructive apnea and less periodic breathing compared to premature controls. These observed differences within groups were subtle and clinically insignificant. Other parameters studied were not different. When term and preterm infants were compared, preterm infants had significantly higher central apnea, obstructive apnea and periodic breathing rates. These differences appeared to be related to gestational age differences, not to drug exposure. There was no evidence that exposure to cocaine and other drugs actually inhibited respiration.

Adult↗
PubMed1994

Testing the limits of freedom of contract: the commercialization of reproductive materials and services.

This article examines the cases for and against commercializing, or "commodifying," reproductive materials and services. Using a supply/demand third-party framework, three basic scenarios in which commercial-exchange relationships may be possible--exchange of gametes and zygotes, exchange of gestational services, and exchange of fetal material--and the major parties of interest, or stakeholders, are identified. The study sketches the liberal, essentialist, and radical contingency theories that shape the debate over the commercialization of reproductive materials and services. The article then attempts to derive some basic governing principles that reflect as much common ground as possible amongst these various normative perspectives, while recognizing that complete reconciliation is impossible. Taken together, these principles are designed to reflect a strategy of "constrained commodification," where commercialization or commodification, that is, financial remuneration, plays a relatively neutral role in the utilization of reproductive materials and services. In light of these principles, the article concludes by sketching legal and regulatory regimes with respect to the exchange of gametes and zygotes, gestational services, and fetal tissue.

Aborted Fetus↗
PubMed1993

Natural wound formation: endodermal responses in experimental primary neural induction in the chick embryo.

Natural wound formation in experimental primary neural induction has been studied by SEM and in paraffin wax sections in embryos from 0 minutes to 10 hours of re-incubation. Stage 4 host and graft embryos were removed from hen's eggs and mounted as for New culture. Graft Hensen's nodes were transplanted into "pockets" created in the host area pellucida and re-incubated for up to 10 hours. Initially the cut edges of the graft establish contact with the host ectoderm layer. After 4 hours the cut edges of the graft move from the host ectoderm to the host endoderm layer. Several small openings form in the host endoderm over the graft tissue. By 6 hours, these openings join to form a single natural wound through which the underlying graft is exposed to the external environment. At 8 hours the graft forms a head-fold and neural folds are evident. During 8 to 10 hours of re-incubation the edges of the graft which attach to the edges of the host endoderm meet in the midline and close the opening in the host endoderm; simultaneously, the graft forms a neural tube. The endodermal wounds form by cell re-arrangement and by a minor contribution from cell loss.

Animals↗
PubMed1992

Studies on wound healing in the neuroepithelium of the chick embryo.

Wound healing has been studied by light microscopy, SEM, and TEM in the neuroepithelium of the early neurula (stages 6 and 8) and advanced neurula (stages 10 and 12) chick embryos. Healing involves two major events: (1) apposition of the wound edges and (2) restitution of the neuroepithelium at the wound site (i.e., restoration of the epithelial integrity of neuroepithelium). Apposition of the wound edges occurs within the first 15 minutes of re-incubation and involves the entire length of the wound. The main event during restoration is a change in the shapes of the rounded cells to elongated forms (i.e., spindle, wedge, and inverted wedge shapes). Wounds of younger embryos heal faster than those of older ones.

Animals↗
PubMed1992

Postnatal development of corticosteroid receptor immunoreactivity in the rat cerebellum and brain stem.

The postnatal development of corticosteroid receptor immunoreactivity in the rat cerebellum and related brainstem nuclei was studied using a type I receptor antiserum, MINREC4, and a type II receptor monoclonal antibody, BUGR2. Type I receptor immunoreactive (ir) Purkinje cells were first observed at postnatal day 5 (P5), and increased to adult levels by P20. Type I-ir cells, presumably migrating granule cells, were observed in the developing molecular layer of the cerebellum at P5. By P30, the density of type I-ir cells in the definitive molecular and granular layers was still less than adult levels. In contrast, type II-ir Purkinje cells were first observed at P15 and increased to adult levels by P20. No type II-ir cells were observed in the proliferative and migratory zones of the molecular layer. By P30, the density of type II-ir cells in the molecular and granular layers was far less than adult levels. In the deep cerebellar nuclei and most brain stem nuclei type I-ir was observed at P5 and developed to adult levels by P30. Type II-ir was observed in the deep cerebellar nuclei, red and medial vestibular nuclei by P15. The pontine and inferior olivary nuclei showed type II-ir cells by P10. Type II-ir in these regions developed to adult levels by P30. The earlier development of type I-ir suggests that the type I receptor may mediate the actions of corticosteroids in the cerebellum and related brain stem nuclei during early postnatal life.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Postnatal development of corticosteroid receptor immunoreactivity in the rat hippocampus.

Postnatal changes in corticosteroid receptor immunoreactivity in the rat hippocampus were examined using an antiserum against a fusion protein containing an N-terminal peptide of the Type I receptor, and a monoclonal antibody against the rat liver Type II-receptor. Age-related regional differences were observed. In the pyramidal cell layer of Ammon's horn, and granule cell layer of the dentate gyrus (DG), the percentage of Type I receptor immunoreactive (Type I-ir) and Type II receptor immunoreactive (Type II-ir) cells was high perinatally, declined sharply by postnatal day 10 (P10), and showed a variable increase to adult levels subsequently. The pyramidal cells of CA1-CA2, subiculum and DG showed a selective increase in Type II-ir in late postnatal life into adulthood, while most other regions showed higher Type I-ir in both early and late postnatal life, suggesting different roles for these receptors during development. Type II-ir was predominantly nuclear in most neurons, except for a transient appearance of cytoplasmic Type II-ir in neurons of the stratum oriens and molecular layers of Ammon's horn and dentate gyrus of P20-P30. Type I-ir was diffusely nuclear and cytoplasmic at all developmental ages. This is suggestive of differential genomic and extragenomic roles for these receptors during postnatal development of the hippocampus.

Animals↗
PubMed1991

Impalpable testis: testicular vessel division in treatment.

Between 1984 and 1989, 110 boys with 130 impalpable testes were investigated and treated. One hundred and six boys underwent laparoscopy. Twenty had bilateral impalpable testes and 13 had a palpable, but maldescended, testis on the other side. Forty-nine testes were absent and one atrophic testis was found in the scrotum. Twelve orchidectomies were performed. One child had a microvascular transfer procedure. The remaining 67 testes were treated by orchidopexy: 28 single-stage and 39 two-stage procedures. One of the single-stage and 29 of the two-stage orchidopexies included division of the testicular vessels. Twenty-three testes examined 12 or more months after staged testicular vessel division revealed a good result in 15.

Adolescent↗