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L Butler

Publications and source records attributed to L Butler.

13 recordsLinked to original sources
PubMed1992

NMDA-receptor mediated electrical epileptogenesis in the organotypic culture of rat hippocampus.

Extracellular field recordings were made in CA1 in the hippocampal explant cultures in oxygenated artificial cerebrospinal fluid. Schaffer collaterals were stimulated with 1-s trains of 60 Hz pulses every 10 min. Seizures were reliably elicited with progressive lengthening over 1-2 h. D-APV, an N-methyl-D-aspartate (NMDA) antagonist, stereoselectively blocked the development of seizures. Thus we have demonstrated that in vitro epileptogenesis occurs in hippocampal explant cultures through NMDA receptor mediated mechanisms.

2-Amino-5-phosphonovalerate↗
PubMed1992

Antenatal maternal serum screening for Down's syndrome: results of a demonstration project.

OBJECTIVES: To assess the implementation of antenatal screening for Down's syndrome in practice, using individual risk estimates based on maternal age and the three serum markers: alpha fetoprotein, unconjugated oestriol, and human chorionic gonadotrophin. DESIGN: Demonstration project of Down's syndrome screening; women with a risk estimate at term of 1 in 250 or greater were classified as "screen positive" and offered diagnostic amniocentesis. SETTING: Hospital and community antenatal clinics in four health districts in London. SUBJECTS: 12,603 women of all ages with singleton pregnancies seen between February 1989 and the end of May 1991, with follow up of the outcome of pregnancy completed to the end of 1991. MAIN OUTCOME MEASURES: Uptake of screening, detection rate for Down's syndrome, false positive rate, odds of being affected given a positive result, and uptake of amniocentesis in women with positive screening results, together with the costs of the screening programme. RESULTS: The uptake of screening was 74%. The detection rate was 48% (12/25), and the false positive rate was 4.1%, consistent with results expected from previous work based on observational studies. There was a loss of detection due to the selective use of ultrasound scans among women with positive screening results. One affected pregnancy occurred among 205 reclassified as negative; this illustrated the danger of false negatives occurring in this group and lends weight to the view that if an ultrasound estimate of gestational age is used it should be carried out routinely on all women rather than selectively among those with positive results. The estimated cost of avoiding the birth of a baby with Down's syndrome was about 38,000 pounds, substantially less than the lifetime costs of care. CONCLUSION: Antenatal maternal serum screening for Down's syndrome is effective in practice and can be readily integrated into routine antenatal care. It is cost effective and performs better than selection for amniocentesis on the basis of maternal age alone.

Amniocentesis↗
PubMed1991

Miller-Dieker syndrome with ring chromosome 17.

A girl presented at 6 weeks of age with failure to thrive and arching of the back. She had various dysmorphic features, hepatosplenomegaly, and developmental delay. The electroencephalogram and cranial ultrasound were abnormal, and a computed tomogram showed lissencephaly and apparent agenesis of the corpus callosum. Because of frequent aspiration she became oxygen dependent. She later developed intractable convulsions and died at the age of 9 months.

Abnormalities, Multiple↗
PubMed1991

Influence of environmental viral agents on frequency and tempo of diabetes mellitus in BB/Wor rats.

Elimination of environmental viruses by cesarean derivation of the University of Massachusetts colony of BB/Wor rats increased the frequency and accelerated the tempo of spontaneous diabetes among diabetes-prone (DP) rats. In contrast, the viral-antibody-free (VAF) environment did not alter the resistance of pre-VAF diabetes-resistant (DR) rats to spontaneous and RT6+ T-lymphocyte-depletion-induced diabetes. Pre-VAF and VAF rats have essentially the same lymphocyte subsets, and VAF-DP rats are susceptible to the adoptive transfer of diabetes and to the diabetes-accelerating effects of polyinosinic-polycytidylic acid injections. These results suggest that the presence of environmental viral pathogens may act to inhibit effector cell function in lymphopenic DP rats while enhancing effector cell activity in nonlymphopenic DR rats.

ADP Ribose Transferases↗
PubMed1990

De novo deletion of Xp22.2-pter in a female with linear skin lesions of the face and neck, microphthalmia, and anterior chamber eye anomalies.

A female infant is described with an unusual combination of eye and skin findings. Raw linear skin lesions on the face and neck were present at birth, healing to leave pigmented streaks. In addition she had left sided microphthalmia and bilateral sclerocornea. Chromosome analysis showed a terminal deletion of the short arm of the X chromosome (Xp22.2--pter). Clinical findings were similar to three previously described children with translocations involving Xp22.3. The condition probably represents a new syndrome distinct from incontinentia pigmenti and Goltz syndrome.

Chromosome Deletion↗
PubMed1977

Pathology on-call.

Explore the source record for details and available documents.

Appointments and Schedules↗
PubMed1977

Recombination values and their errors.

Two four-point testcrosses comprising 87,000 tomato plants were grown and the data collected from 28 subgroups. Each subgroup consisted of 2,000 or 5,000 plants and should give a valid estimate of the three recombination values. The 28 values for each interval give more outlyers (23% are outside the 95% limits set by the standard deviation calculated by the binomial formula square root of p q/n) than would be expected by chance. If each subgroup was regarded as the control and the other groups tested against this, then 42% of the time the two subgroups would be significantly different. It is suggested that there are many cases in the literature where this comparison has been made and the significant difference wrongly ascribed to treatment. While the causes of these changes in recombination value are unknown and therefore uncontrollable, they must be anticipated in all such studies. Control and treatment must be replicated enough that chance extreme values will not be attributed to treatment.

Crosses, Genetic↗
PubMedDate not supplied

Retrieval of the critically ill in South Australia: a coordinated approach.

A system is described for the stabilization and evacuation of the critically ill in South Australia, with a discussion of experience in 278 patients. The integration of activities of peripheral medical practitioners, major teaching hospitals, and the ambulance transport authority (St John Ambulance Council) is paramount. Modes of communication are by "urgent line" telephone and radio. Advanced life-support equipment is portable, may be placed in any ambulance vehicle, and is used and maintained principally by the staff of intensive care units. The design characteristics of a suitable road vehicle and fixed-wing aircraft are considered, with emphasis on dimensions for the particular needs of advanced life-support. The cost of transporting such a patient is approximately two-thirds of an average bed day cost in a public hospital, plus the basic ambulance charge. The number of patients who need such measures is 0.2% of the total number of patients carried by ambulance per annum.

Adolescent↗