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Biomedical subjects

L Lau

Publications and source records attributed to L Lau.

33 records · Page 2Linked to original sources
PubMed1994

Impairment in shifting attention in autistic and cerebellar patients.

MRI and autopsy evidence of early maldevelopment of cerebellar vermis and hemispheres in autism raise the question of how cerebellar maldevelopment contributes to the cognitive and social deficits characteristic of autism. Compared with normal controls, autistic patients and patients with acquired cerebellar lesions were similarly impaired in a task requiring rapid and accurate shifts of attention between auditory and visual stimuli. Neurophysiologic and behavioral evidence rules out motor dysfunction as the cause of this deficit. These findings are consistent with the proposal that in autism cerebellar maldevelopment may contribute to an inability to execute rapid attention shifts, which in turn undermines social and cognitive development, and also with the proposal that the human cerebellum is involved in the coordination of rapid attention shifts in a fashion analogous to its role in the coordination of movement.

Adolescent↗
PubMed1992

The effect of inhaled allergen on circulating basophils in atopic asthma.

There is increasing evidence for the role of basophils in the allergen-induced late asthmatic response (LAR). To study the effect of inhaled allergen on basophil function in subjects with asthma, ex vivo basophil spontaneous histamine release (SHR) in peripheral blood and plasma histamine was measured before and 2, 5, 10, and 15 minutes, and 2, 4, 6, and 8 hours after allergen bronchial challenge (allergen study day) in six subjects with atopic asthma. Allergen inhalation induced an early response and LAR consisting of a mean (+/- SD) 32.5% (+/- 7.9%) and 28.8% (+/- 7.7%) fall in FEV1, respectively. As a control for the effects of bronchoconstriction, on another occasion, methacholine challenge was performed to produce a mean 33.4% (+/- 3.4%) fall in FEV1 during the early response and no LAR, and blood was obtained to measure basophil histamine release (HR) and plasma histamine. There was a small, but significant (p less than 0.05), rise in median SHR from 4.6% to 6.1% of total basophil histamine after allergen but not after methacholine inhalation. HR remained high after allergen inhalation during the 8 hours of study, whereas it demonstrated a steady, significant, decrease between 4 to 8 hours after methacholine inhalation. No significant changes in plasma histamine were recorded on either allergen or methacholine study days. On a third occasion, SHR was measured after challenge with physiologic saline to control for any effects of methacholine on SHR, and a decrease in HR was recorded during the day similar to HR observed after methacholine challenge. These studies suggest an enhancing effect of inhaled allergen on SHR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Neoplastic involvement of the sacroiliac joint: MR and CT features.

The radiological findings in five patients with pelvic soft tissue neoplasms directly involving the sacroiliac joint, are described. All patients had Computed Tomography (CT) examinations, two of the patients also having Magnetic Resonance Imaging (MRI). The role of imaging in this uncommon entity is discussed as well as the importance of making this diagnosis, thereby excluding unilateral sacroiliitis. The therapeutic implications of this diagnosis relate to local neural involvement, especially the sciatic nerve, and the fact that involvement of the sacroiliac joint by tumors significantly compromises chances of a successful surgical outcome. The role of MR in this condition is not yet certain, but it may prove to be the method of choice in view of its excellent depiction of skeletal neoplasms.

Adult↗
PubMed1984

CT appearance of a prosthetic methyl methacrylate mass mistaken for abscess.

A nonopaque methyl methacrylate mass that had the appearance of an abscess in a postoperative CT scan of the spine is described. Contained gas produced an attentuation range of +20 to -300 HU, with an average of -80 to -250 HU. This finding was confirmed by CT examination of a separate cement mass removed from a similar patient.

Abscess↗
PubMed1980

The recurrence risk for neural tube defects in the United States: a collaborative study.

To determine the recurrence risk for patients with one prior pregnancy affected with neural tube defects (NTD), the authors have pooled data from eight testing centers. In 831 pregnancies studied because one sib was affected with an NTD, the recurrence rate was 3.0%, with 95% confidence limits of 2.0-4.3%, and 99% confidence limits of 1.8-4.8%. The recurrent lesion, whether spina bifida or anencephaly, tended to be concordant with the first to a significant degree. Only 12.2% of recurrent NTD were different from the first, with 95% confidence limits of 4.1-26.2%, and 99% confidence limits of 1.7-30.9%. Both an accurate recurrence risk and the information that a recurrent NTD lesions tends to be concordant with that in the first affected child are useful in the genetic counseling of patients in the United States and in the selection of appropriate prenatal diagnostic studies.

Female↗
PubMed1980

Synthesis of the human insulin gene. Part IV. New synthetic deoxyribooligonucleotide adaptors and primer for DNA cloning and sequence analysis.

The chemical synthesis of four new deoxyribooligonucleotides to be used as adaptors in molecular cloning of DNA for expression studies is described. These are (i) start-adaptor, (ii) stop-adaptor, (iii) conversion adaptor to insert ribosomal binding site, and (iv) retrieving adaptor. We have also synthesized a 19-bases-long primer, 5'-TTGTAAAACGACGGCCAGT-3' to increase the speed of DNA sequence analysis and also demonstrated its application using single-stranded M13 DNa vector.

Base Composition↗
PubMed1978

The production of hemopoietic growth factors by PHA-stimulated leukocytes.

Conditioned medium from cultures of phytohemagglutinin-stimulated leukocytes has been assessed for its content of factors able to stimulate either colony formation by human granulopoietic progenitor cells, or 3H-thymidine incorporation by peripheral leukocytes from leukemic patients. The cell concentration, concentration of phytohemagglutinin and time required for optimal production of factors were investigated. Production of both classes of factors was found to be insensitive to inhibitors of cell proliferation and DNA synthesis, but sensitive to inhibition of protein synthesis by cycloheximide. The production of colony stimulating activity showed a markedly greater sensitivity to cycloheximide than did production of thymidine-incorporating activity. For cycloheximide and most of the other inhibitors studied, factor production by leukemic cell populations was affected to a somewhat greater extent than production by normal leukocytes. Separation by velocity sedimentation of the cells responsible for production provided no evidence for distinct classes of cells producing these two classes of factors.

Cell Division↗
PubMedDate not supplied

[Analysis of paediatric neuro-oncological information on the Internet in German language].

BACKGROUND: The fast growing internet offers easy access to medical information. So far there are limited data concerning the quality of this information. This study examined quality and readability of paediatric neuro-oncological information on the internet in german language. METHOD: Using the search terms "medulloblastoma", "ependymoma", "craniopharyngeoma", "brainstem glioma" and "low grade astrocytoma" in six different search engines, the first 30 universal/uniform resource locators (URLs) of each search engine were assessed. Appropriate Web sites were evaluated in regards to quality using DISCERN-Instrument and checklist rating system. Readability was rated by Flesch Reading Ease score. RESULTS: Out of 889,56 web sites remained evaluable. Most of the sites rated as poor to very poor (49 %), 30 % rated as fair and 21 % as good to very good. Readability was scored as very difficult with complex vocabulary content limiting the usefulness of good web sites. CONCLUSIONS: Search-ing for childhood brain tumours via internet is time consuming and most often ineffective. There is a lack of high-quality and comprehensible information on childhood brain tumours on german web sites. Cooperation of scientific medical societies and the Federal Ministry of Health is essential to provide comprehensible and high-quality information on internet as an effective and supportive resource for patients and their relatives.

Age Factors↗