Biomedical subjects

R Watson

Publications and source records attributed to R Watson.

At least 199 records · Page 11Linked to original sources

PubMed1995

Reproducibility of allergen-induced early and late asthmatic responses.

BACKGROUND: Constant-dose allergen inhalation challenges are frequently used to examine the effect of antiasthma drugs on the allergen-induced early and late asthmatic responses. The end-point measurements in such studies are the maximal early and late percent decreases in the forced expiratory volume in 1 second (FEV1). OBJECTIVE: Our purpose was to observe the reproducibility and to determine the sample sizes required for such studies. METHODS: Twenty-eight subjects with allergen-induced early and late responses were studied with two constant-dose allergen challenges separated by 2 to 12 weeks. The early response was measured as the maximum percent decrease in FEV1 during the first 2 hours and the late response as the maximum percent decrease in FEV1 between 3 to 7 hours. RESULTS: The mean +/- SEM early responses were 23.1% +/- 1.0% and 24.7% +/- 2.0%, whereas the mean late responses were 23.3% +/- 2.0% and 24.5% +/- 2.2%. Reproducibility of measurements were such that fewer than eight subjects are required, to show 50% attenuation of either the early or late response (with 90% power). CONCLUSIONS: The method of constant-dose allergen challenge is a sensitive tool for detecting changes in early and late asthmatic responses after the use of antiasthma medication.

Administration, Inhalation↗

PubMed1995

Relevance and definition.

The study examined whether the use of superordinate terms in children's definitions was predicted by relevance theory. Two hundred and six children aged five to ten years gave definitions for 16 basic-level words and four superordinate words from natural kind and artefact semantic domains. Superordinate terms were used more frequently when they supported more inferences. This was evidenced by their more frequent use in natural kind than in artefact domains, and more frequent use when the superordinate was itself defined by a semantically complex expression. When used, superordinates also usually occurred at the beginning of the definitional expression. It is argued that these findings reflect the speaker's intention to achieve optimal relevance, that is, to achieve maximum contextual effects with the least processing effort.

Child↗

PubMed1995

Reassembly of Golgi stacks from mitotic Golgi fragments in a cell-free system.

Rat liver Golgi stacks were incubated with mitotic cytosol for 30 min at 37 degrees C to generate mitotic Golgi fragments comprising vesicles, tubules, and cisternal remnants. These were isolated and further incubated with rat liver cytosol for 60 min. The earliest intermediate observed by electron microscopy was a single, curved cisterna with tubular networks fused to the cisternal rims. Elongation of this cisterna was accompanied by stacking and further growth at the cisternal rims. Stacks also fused laterally so that the typical end product was a highly curved stack of 2-3 cisternae mostly enclosing an electron-lucent space. Reassembly occurred in the presence of nocodazole or cytochalasin B but not at 4 degrees C or in the absence of energy supplied in the form of ATP and GTP. Pretreatment of the mitotic fragments and cytosol with N-ethylmaleimide (NEM) also prevented reassembly. GTP gamma S and A1F prevented reassembly when added during fragmentation but not when added to the reassembly mixture. In fact, GTP gamma S stimulated reassembly such that all cisternae were stacked at the end of the incubation and comprised 40% of the total membrane. In contrast, microcystin inhibited stacking so that only single cisternae accumulated. Together these results provide a detailed picture of the reassembly process and open up the study of the architecture of the Golgi apparatus to a combined morphological and biochemical analysis.

Animals↗

PubMed1995

Characterization of a cis-Golgi matrix protein, GM130.

Antisera raised to a detergent- and salt-resistant matrix fraction from rat liver Golgi stacks were used to screen an expression library from rat liver cDNA. A full-length clone was obtained encoding a protein of 130 kD (termed GM130), the COOH-terminal domain of which was highly homologous to a Golgi human auto-antigen, golgin-95 (Fritzler et al., 1993). Biochemical data showed that GM130 is a peripheral cytoplasmic protein that is tightly bound to Golgi membranes and part of a larger oligomeric complex. Predictions from the protein sequence suggest that GM130 is an extended rod-like protein with coiled-coil domains. Immunofluorescence microscopy showed partial overlap with medial- and trans-Golgi markers but almost complete overlap with the cis-Golgi network (CGN) marker, syntaxin5. Immunoelectron microscopy confirmed this location showing that most of the GM130 was located in the CGN and in one or two cisternae on the cis-side of the Golgi stack. GM130 was not re-distributed to the ER in the presence of brefeldin A but maintained its overlap with syntaxin5 and a partial overlap with the ER-Golgi intermediate compartment marker, p53. Together these results suggest that GM130 is part of a cis-Golgi matrix and has a role in maintaining cis-Golgi structure.

Amino Acid Sequence↗

PubMed1995

One hundred anti-Ro (SS-A) antibody positive patients: a 10-year follow-up.

To explore further the varied clinical expression of anti-Ro(SS-A) antibody positive patients and to determine the outcomes of these patients, we followed 100 anti-Ro(SS-A) antibody positive patients, originally seen at the Johns Hopkins Medical Institutions in 1982 and 1983, over a 10-year period. The results of this study indicate that anti-Ro(SS-A) antibody positive patients have a diverse clinical presentation and that the anti-Ro(SS-A) antibody response generally persists for years. Some of these patients appear to have a static disease process for years. However, 65% (51, including 13 deaths, of 78 patients) of the patients for whom we had follow-up data had a chronic (10 years or greater) progressive disease process. Black patients, in general, have an earlier onset of disease and may have a more severe disease than white patients. At least 25% of our anti-Ro(SS-A) antibody positive patients demonstrated a dynamic change in clinical presentation with the development of Sjögren syndrome and/or a progressive "rheumatoid-like" arthritis. Interstitial pulmonary disease, central nervous system disease, and vasculitic insults occur frequently in these patients. Renal disease occurred in 19 anti-Ro(SS-A) positive patients, and in 47% of these renal disease patients, no anti-DNA antibodies (dsDNA or ssDNA) were detected. Cutaneous manifestations are prominent in anti-Ro(SS-A) antibody positive patients with lupus. Photosensitivity and a malar dermatitis were the most common features. Twenty percent of lupus patients had discoid lesions, and 20% had SCLE lesions. Based on this study, we believe that anti-Ro(SS-A) antibody positive patients should be routinely evaluated for the emergence of systemic features. Since these systemic features are at least in part, if not solely, the result of inflammation, early treatment with steroids and/or immunosuppressive agents may minimize the damage and influence in a positive manner the significant morbidity and mortality observed in some anti-Ro(SS-A) antibody positive patients.

Adolescent↗

PubMed1995

Primary osteogenic sarcoma of the kidney.

Primary renal osteogenic sarcoma is a rare tumour which requires differentiation from osteoid formation in sarcomatoid variants of renal cell carcinoma. The diagnosis in this case was suggested pre-operatively by marked elevation of serum alkaline phosphatase in the absence of bone disease. The poor prognosis is emphasized.

Alkaline Phosphatase↗

PubMed1995

Unilateral Beau's lines in childhood reflex sympathetic dystrophy.

Reflex sympathetic dystrophy is characterized by severe pain and autonomic dysfunction in a limb, usually after an injury. We describe a patient with childhood reflex sympathetic dystrophy with unilateral Beau's lines on the nails of the affected hand. Unilateral Beau's lines have not been described previously in this condition to our knowledge, and we discuss their possible pathogenesis.

Child↗

PubMed1995

Cutis marmorata telangiectatica congenita associated with a double aortic arch.

We report a patient with cutis marmorata telangiectatica with the hitherto unreported anomaly of a double aortic arch. The presence of two major vascular anomalies in this patient may be secondary to a developmental defect of the mesoderm during embryogenesis.

Aorta, Thoracic↗

PubMed1995

Frontal lobe neglect in monkeys.

Using a crossed-response task, monkeys with neglect induced by frontal lesions appear to have motor rather than sensory neglect. However, the crossed-response task may not reveal sensory neglect (inattention) if no perceptual discrimination is required. We therefore trained two monkeys in a perceptually complex crossed-response task. Following unilateral frontal (arcuate gyrus) ablation, we found no contralateral perceptual disorders or sensory neglect in either monkey but did find a failure to respond with the contralateral arm (motor neglect) in both monkeys. We also found that the monkeys made more incorrect responses with the arm ipsilateral to the lesion than they did with the contralateral arm. The errors made by the ipsilateral arm could be a compensatory strategy or a disinhibition phenomenon. Because these incorrect responses were not rewarded and became more frequent as motor neglect improved, the incorrect responses of the ipsilateral arm are not a compensatory strategy, but rather a defect we term "disinhibition hyperkinesia" or "allokinesia."

Animals↗

PubMed1995