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Biomedical subjects

R Partridge

Publications and source records attributed to R Partridge.

At least 19 recordsLinked to original sources

I-123 iofetamine SPECT scan in systemic lupus erythematosus patients with cognitive and other minor neuropsychiatric symptoms: a pilot study.

Accurate diagnosis of central nervous system (CNS) lupus remains difficult, especially when the manifestations are of subtle cognitive and affective changes. This pilot study reports on the use of I-123 iofetamine single photon emission computerized tomography (SPECT) scans in 18 such patients with documented systemic lupus erythematosus. Eight of the 18 scans were abnormal (44%), four in a diffuse bi-temporo-parietal pattern previously noted only in Alzheimer's disease, and four with large focal deficits. Neither the existence of the abnormal scan nor the particular pattern of abnormality correlated with the results of other diagnostic tests. These preliminary results raise the possibility that SPECT scans may offer an additional valuable diagnostic instrument in CNS lupus, although further studies are necessary to delineate their precise role.

Adolescent

The timing of menarche in juvenile rheumatoid arthritis.

A study of the age of menarche in juvenile rheumatoid arthritis (JRA) patients was undertaken to determine what factors affect the timing of menarche. There was a significant difference between the mean age of menarche for the 68 JRA patients and 46 controls (p = 0.015). No clear etiology for this difference was elucidated. Polyarticular-onset JRA patients had the oldest age of menarche, but this finding was of marginal statistical significance (p less than 0.05,pcorr less than 0.25). The multivariate model that included onset type, steroid use, and duration of disease weakly predicted age of menarche in the JRA group. This model suggests that, exclusive of height and weight parameters, duration of disease was the most important predictor of menarche in JRA.

Adrenal Cortex Hormones

Adult and child discrimination of CV syllables differing in voicing onset time.

The purpose of this experiment was to determine whether age-related differences would be observed for discrimination of synthesized, 5-formant consonant-vowel syllables that differed in voicing onset time (VOT) of the initial consonant. Just noticeable differences (JNDs) were measured relative to the end points of the stimulus continuum, using a "same"-"different," adaptive procedure with trial-by-trial feedback/reinforcement and "catch" trials, in which members of the stimulus pair were identical syllables. 6-8-year-old children required significantly longer VOTs for syllabic discrimination than did adults. Adults' JNDs relative to [pa] at the end of the stimulus continuum with longer VOTs were significantly larger than their JNDs relative to [ba], as would be expected on the basis of psychoacoustic considerations, but neither 6-8-nor 8-11-year-old children showed this trend. Performance on "catch" trials for both groups of children was significantly poorer than for adults. Outcomes corresponded to results of other investigations that have reported that children require more acoustic information than adults to achieve the same performance criterion.

Adolescent

Decreased calcium dependence of lymphoblastoid cell lines compared with Burkitt lymphoma cell lines.

The extracellular calcium level required for proliferation was compared in B lymphoid cell lines from various sources by determining the calcium concentration at which long-term proliferation was inhibited by 50% (CaPD50). Fourteen Burkitt lymphoma (BL) lines had a mean CaPD50 of 44 +/- 28 microM whereas 45 lymphoblastoid cell lines (LCLs) obtained by in vitro transformation of B lymphocytes with Epstein-Barr virus (EBV) had a mean CaPD50 of 3.6 +/- 1.8 microM. This difference applied also to autologous BL lines and LCLs established from the same patient. The decreased calcium requirement of virally-transformed compared with tumour-derived cell lines therefore appears to be a universal phenomenon in mammalian cells. Within the BL group, no correlation was found between the calcium requirement for proliferation and presence or absence of the EBV genome. Arrest of BL lines and LCLs occurred in the G1 phase of the cell cycle and was readily reversed by addition of calcium to the medium. One anomalous LCL was found which showed a high CaPD50 (43 +/- 6 microM) and accumulated in both G1 and G2. These results, in combination with a previous study of EBV transformation in vitro, indicate that the calcium dependence of B lymphocytes generally decreases in the following order: normal cells greater than BL cells = early stage transformation greater than LCL. The 2 transformed phenotypes thus distinguished in human lymphoid cells may offer unique opportunities for defining the status and expression of EBV in vitro and in vivo.

Burkitt Lymphoma

A new prostaglandin E1 analogue (CL115,574). I. antisecretory and cytoprotective effects in the rat.

The effects of a new analogue of PGE1 (CL115,574) on gastric acid secretion, mucus secretion and protection against stress and indomethacin-induced ulcers were studied in the rat. CL115,574 was more potent than PGE1 and cimetidine in inhibiting acid secretion. CL115,574 protected against the development of stress and indomethacin-induced ulcers and prevented the indomethacin-induced decrease in hematocrit at an ED50 (3 micrograms/kg) far below the antisecretory ED50 (1 microgram/kg). While inhibiting acid secretion, CL115,574 increased the volume of gastric secretion indicating a stimulation of nonparietal cell secretion by the rat stomach. In addition the compound stimulated the secretion of mucus into the gastric juice. On the basis of its potency as an inhibitor of acid secretion and these additional effects which are indicative of cytoprotective activity, CL115,574 should be further studied as a possible anti-ulcer agent in man.

Alprostadil

Prostaglandin E antagonist activity of 11, 15-bisdeoxy prostaglandin E1 and congeners.

d,l-11, 15-bisdeoxy PGE1 and certain of its congeners were shown to inhibit gerbil colon contractions induced by l-PGE1. While some of these compounds were selectively antagonistic of PGE1-induced contractions, others additionally inhibited the gerbil colon agonist activities of l-PGE2alpha and acetylcholine. The PGE1 inhibitory activity was apparently competitive in nature. With relatively weak potencies, the bisdeoxy PGE congeners displaced 3H-PGE1 from a fat cell binding site, suggesting competition for a common, putative receptor. Structure-activity relationships and potential utility of these analogs are discussed.

Animals

Inhibition of prostaglandin-mediated ocular inflammatory responses by 4-biphenylacetic acid.

4-Biphenylacetic acid (BPAA),a prostaglandin-synthesis inhibitor, was tested for its effects on prostaglandin-related, laboratory models of ocular inflammation. Topically applied, BPAA inhibited arachidonic acid, but not prostaglandin E-induced increases in rabbit intraocular pressure (IOP). BPAA inhibited the IOP response to alkali burn and altered IOP changes following paracentesis. In vitro, BPAA inhibited prostaglandin production from arachidonic acid in cell-free preparations of rabbit uvea. It is suggested that BPAA may be useful for the therapy of ocular inflammatory disease.

Acetates