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Biomedical subjects

A Stockman

Publications and source records attributed to A Stockman.

48 records · Page 3Linked to original sources
PubMed1986

The spectral sensitivities of the middle- and long-wavelength cones: an extension of the two-colour threshold technique of W S Stiles.

When a tiny centred test flash is presented on a small concentric background, the threshold rises with background radiance more quickly than Weber's law would predict. It is argued that under such conditions it is possible, by means of a test sensitivity method, to isolate either the M-cone or the L-cone types throughout the visible spectrum. As predicted, double-branched M- and L-cone tyr functions are found when the test flash and the field are of the same wavelength. From the independent vertical displacements of the two branches as test wavelength is varied, it is possible to derive spectral sensitivities that agree well with dichromatic sensitivities and König fundamentals. The test sensitivities deviate from pi 4 at longer wavelengths and from pi 5 at shorter wavelengths.

Adaptation, Ocular↗
PubMed1986

Genetic markers in rheumatoid arthritis relationship to toxicity from D-penicillamine.

In a 3-centre study involving 144 patients with rheumatoid arthritis (RA), a relationship between side effects from D-penicillamine and HLA antigens, allotypic markers of the IgG heavy chain (Gm) and allotypes of complement components Bf, C4A and C4B was sought. There was a significant association between proteinuria induced by D-penicillamine and the antigens DR3 and B8. However, the presence of DR2 seemed to protect against the development of proteinuria. Thrombocytopenia from D-penicillamine was significantly associated with HLA-A1 and DR4; 15 of 23 patients who possessed both antigens developed thrombocytopenia (p less than 0.001 uncorrected, approximate relative risk (RR) = 5.5). A null complement allele located at the C4B locus (C4BQO) was also associated with thrombocytopenia from D-penicillamine (p less than 0.005, RR = 17.3). Our study confirms the findings from other series which indicate that there is a genetic predisposition for the development of proteinuria from D-penicillamine in RA and suggests that this may also be the case in D-penicillamine induced thrombocytopenia.

Arthritis, Rheumatoid↗
PubMed1980

Frequency of chondrocalcinosis of the knees and avascular necrosis of the femoral heads in gout: a controlled study.

An association between urate gout and chondrocalcinosis has been suggested in several studies, but the situation remains ill-defined because of lack of appropriate controls, small numbers of patients studied, or retrospective investigation. An association has also been claimed between gout and avascular necrosis of the femoral head. 138 patients with gout and 142 non-gouty control subjects were carefully matched for age and x-rays were taken of the knees and pelvis. Chondrocalcinosis of the knees was detected in 8 patients with gout (5.8%), no cases being found in the control group. The difference is significant (P less than 0.025). Deposits were linear or irregular. Six of the 8 patients gave a history of acute synovitis of the knees; fluid had been aspirated in 2 of them, urate crystals being found in one and no crystals in the other. Six of 8 patients showed evidence of chondrocalcinosis elsewhere. No association was apparent between chondrocalcinosis and the presence of tophaceous deposits or renal impairment, though the duration of gout appeared to be longer in the patients with chondrocalcinosis than in the other gout patients and osteoarthrosis of the knees commoner. There was no evidence of other metabolic disorders commonly associated with chondrocalcinosis. No cases of avascular necrosis of the femoral head were found.

Adult↗
PubMed1980

Double-blind trial of feprazone and phenylbutazone in acute gout.

A double-blind trial was carried out in 24 patients with acute gout to compare the efficacy and tolerance of feprazone, a non-steroidal anti-inflammatory drug, with that of phenylbutazone. Patients received 800 mg of either drug daily for 2 days and then 600 mg daily for up to 8 days. The results of patient assessment showed there was no significant difference between the two groups in time taken either to significant improvement or to final resolution of the gout attack. No side-effects were reported with either drug.

Acute Disease↗
PubMed1980

Postoperative vomiting treated with domperidone. A double-blind comparison with metoclopramide and a placebo.

In a double-blind comparison of domperidone 10 mg, domperidone 4 mg, metoclopramide 10 mg and a placebo, 176 adult patients were given an intravenous injection of one of these substances after postoperative vomiting had occurred. Patients were then observed for 6 hours. Those who failed to respond sufficiently to the double-blind injection were given an open dose of domperidone 4 mg i.v. Vomiting recurred in 52% of patients in each of domperidone groups compared with 75% of patients in the metoclopramide group and 84% of patients in the placebo group. Thus domperidone was significantly more effective than the other two substances (p < 0.05). Significantly more patients in the placebo group required a supplementary injection than in the domperidone and metoclopramide groups (p < 0.05). No side effects were observed in any patient.

Adult↗
PubMed1979

Difficulties in the use of D-penicillamine in the treatment of rheumatoid arthritis.

The difficulties encountered in administering D-penicillamine to 40 patients with rheumatoid arthritis (RA) over a six to 24 month period are recorded. Side-effects were frequent. Proteinuria occurred in 13 patients (33%) mainly in the fourth to the sixth month. Renal biopsies were performed in six patients and all showed light microscopy abnormalities. Electron microscopy performed in five patients revealed subepithelial deposits in all and in addition some had mesangial and subendothelial deposits. Seven patients (17.5%) developed eight episodes of thrombocytopaenia which was quickly reversed on cessation of treatment or reduction in dosage. On the positive side, there was significant improvement in most parameters of disease activity at six, 12 and 18 months compared to the pretreatment levels, but the results at two years were less impressive. Reduction in steroid dosage was considerable and was greater than half the mean pretreatment dose after two years but the absence of a control group makes the full significance of these uncertain. Patients on high and low dosage regimens were compared over a 12 month period of treatment. Although the differences were not statistically significant, withdrawals and side-effects were less frequent in the low dose group.

Adolescent↗
PubMed1978

Postoperative nausea and vomiting treated with domperidone (r 33812) an open and a double-blind study.

The effect of domperidone on postoperative nausea and vomiting was evaluated in two consecutive studies. Fifty-eight patients with postoperative nausea and vomiting were included in an open pilot study and 38 other patients in a double-blind trial. In the first study 4 mg of domperidone was found to be significantly superior to 2 mg, in controlling nausea and vomiting. In the double-blind trial, vomiting recurred significantly later in domperidone than in placebo-treated patients. Side-effects were not seen nor reported in either study.

Antiemetics↗
PubMed1976

Comparison of effectiveness of mefenamic acid and ibuprofen in treatment of rheumatoid arthritis.

This paper reports a double-blind crossover trial comparing mefenamic acid (1500 mg/day) with ibuprofen (1200 mg/day) in the treatment of patients with rheumatoid arthritis receiving maintenance salicylate therapy. Both drugs were used in three divided doses. Mefenamic acid compared favourably with ibuprofen. In the adopted dose regimes the side effects from both drugs were mild and almost exclusively gastrointestinal.

Arthritis, Rheumatoid↗
PubMedDate not supplied

Two signals in the human rod visual system: a model based on electrophysiological data.

In the human rod visual system, self-cancellation of flicker signals is observed at high rod intensity levels near 15 Hz, both perceptually and in the electroetinogram (ERG). This and other evidence suggests that two rod signals are transmitted through the human retina with different speeds of transmission. Here we report a series of flicker ERG recordings from a normal observer and an observer who lacks cone vision. From these results, we propose a quantitative model of the two rod signals, which assumes (1) that the amplitude of the slow signal grows linearly with log intensity but then saturates at approximately 1 scot. td; (2) that the amplitude of the fast signal grows linearly with intensity; (3) that there is a difference in time delay of approximately 33 ms between two rod signals of the same polarity (or of approximately 67 ms if the signals are of inverted polarity); and (4) that the time delay of both signals declines linearly with log intensity (by approximately 10 ms per log scot. td). These simple assumptions provide a remarkably good account of the experimental data. Our results and model are relevant to current anatomical theories of the mammalian rod visual system. We speculate that the slower signal in the human ERG may reflect the transmission of the rod response via the rod bipolars and the AII amacrine cells, while the faster signal may reflect its transmission via the rod-cone gap junctions and the cone bipolars. There are, however, several objections to this simple correspondence.

Adult↗
PubMedDate not supplied

Domperidone in the treatment of postoperative vomiting: a double-blind multicenter study.

Domperidone was compared with placebo in a multicenter double-blind study of 116 patients (15 to 80 years) with postoperative vomiting. After vomiting had occurred, the patients received either domperidone 10 mg or placebo IV. Patients were then followed for at least 6 hours or until a 2nd injection of domperidone 10 mg from an open supply was needed. The period of time until an additional injection was registered and compared between the 2 treatment groups. Fifty-nine percent of the placebo patients needed a 2nd injection before the end of the 6-hour follow-up, compared with only 35% of the domperidone patients (p less than 0.05). When a 2nd injection was required, the time elapsed before it was needed was longer (p = 0.01) in the domperidone group (median 150 minutes) than in the placebo one (median 120 minutes). There were no significant side-effects.

Antiemetics↗