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Publications (33)63.85 Total impact

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    ABSTRACT: Rats restrained in plexiglass cylinders received either a continuous series of sub-perception transcranial electrical stimuli or an identical series of stimuli presented in trains separated by “off” periods when no current was passed. The core (rectal) and surface (tail) temperatures were monitored at intervals over 60 min and compared with sham-treated animals which had been connected to the electrodes but had received no current. The mild restraint procedure had no discernible effect on body temperature because there was no significant change in sham-treated rats at any time interval up to 60 min and the sham-treated values did not differ from the basal (zero time) measurement. The rats receiving both modes of electrostimulation had significantly higher core temperatures than the sham-treated animals. The surface temperature of the rats receiving the interrupted current was lower than the shams after 5 min treatment, but there was no significant difference between these groups of rats at the other time intervals monitored. Conversely, although the surface temperature of the continuous current-treated rats was the same as the shams at 5 min, it was significantly higher than both the sham and interrupted-treated animals at every other time interval examined. The possible origin of this difference and its significance in antinociceptive testa involving thermal challenges applied to the tail are discussed.
    07/2009; 8(2):179-187.
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    ABSTRACT: The antinociceptive action of a transcranially-applied, sub-perception, electrical stimulus was distinguished from the effect of mild restraint stress by comparing the temporal characteristics of the two analgesic responses in two experimental tests. Rats restrained in perspex tubes received either transcranial sub-perception electrostimulation treatment (TCET) at 12 μA, 10 Hz, or were sham-treated. Sham treatment for 5 or 10 but not 20, 40, 60 or 120 min produced an antinociceptive effect in the tail flick latency (TFL) test. The withdrawal latencies in the TFL test were significantly longer in the rats that received TCET while being restrained for 10, 20 and 40 but not 5, 60 or 120 min, compared with sham animals comparably restrained for the same periods of time. Rats restrained and receiving electrical stimuli for 20, 40 or 60 but not 5, 10 or 120 min exhibited a significantly decreased abdominal constriction (AC) response to intraperitoneal injection with hypertonic saline, compared with sham animals restrained for similar periods of time. These data indicate that the arousal induced by the obligatory handling and mild restraint produces a transient antinociceptive effect in the TFL test. Concomitant administration of a sub-perception current induced an antinociceptive effect which persisted and increased after the current had ceased. In the AC test, an antinociceptive effect was apparent only if the sub-perception current was administered, and this also increased after cessation of current.
    07/2009; 9(2):167-176.
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    ABSTRACT: The concentration of noradrenaline (NA) and its principal metabolite methoxyhydroxyphenylglycol (MHPG) was determined in five brain regions of rats that received either no treatment, or restraint for 5, 10, 20, 40, 60 or 120 min. Similar groups of rats received a transcranial sub-perception electrical stimulation (TCET) while being restrained for a similar period of time. Plasma was analyzed by radioimmunoassay techniques for adrenocorticotropic hormone (ACTH), corticosterone (cort) and B-endorphin (BE). NA concentration in the hypothalamus was significantly higher than the basal values in both sham and treated rats at each time interval. With the exception of the hypothalamus and pituitary, MHPG concentration was significantly higher in all the restrained animals than the basal controls; at 10 and 20 min, the value in the rats receiving TCET was significantly lower than that of the sham-treated animals, thereafter increasing to levels significantly higher than that of the shams. The plasma ACTH, cort and BE immunoreactivity (-Ir) was generally higher than the basal controls in all except the last (120 min) sample. In the TCET-treated rats ACTH-Ir was significantly lower than the shams after 10 and 20 min, although the sham value declined below the basal at 120 min. In the TCET-treated rats plasma cort-Ir did not correspond with ACTH-Ir and was significantly higher than the shams at 10, 20 and 40 min. BE-Ir was significantly higher in the TCET-treated group in comparison with the shams at 5 min only. These data show temporal differences between concentrations of neurohumoral substances associated with the response to stressful stimuli in similarly restrained rats which differed only in whether or not they received a concomitant sub-perception microelectrostimulus.
    07/2009; 9(2):177-186.
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    ABSTRACT: Female rats, anaesthetized with hexobarbital, regained their righting reflex more rapidly following electrostimulation than sham-treated controls. The extent of the decreased sleeping times in these animals varied according to the frequency (cycles per second) of the electrostimulation applied. The frequency which produced the largest decrease in sleeping time was 10 Hz. Determination of the activity of some microsomal enzymes indicated that the decreased sleeping time was not the result of increased hepatic enzyme activity. Animals which had received prior treatment with naloxone exhibited increased sleeping times following barbiturate administration, but the effects of electrostimulation on the sleeping time at 10 Hz was diminished, while the effect of electrostimulation at high frequency (500 Hz) was enhanced. Although repeated daily administration of hexobarbital progressively decreased sleeping times for all the animals, electrostimulation decreased the sleeping times of the treated rats by a similar percentage of the control animals on each successive day. Electrostimulation at a frequency of 10 Hz produced a significant decrease in serum corticosterone levels, whereas 500 Hz resulted in an increase.
    Drug Development Research 10/2004; 2(1):73 - 79. · 0.87 Impact Factor
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    ABSTRACT: Rats aged 6, 12, 24, 36, and 52 weeks were subjected to social isolation for 4 days, while littermates housed in groups of six for the same period served as controls. The isolation treatment resulted in a 2-fold increase in the serum corticosterone level of all except the youngest animals in whom the hormone level was greater than 4 times that of their age-matched controls. Hepatic microsomal protein was highest in the 24-week-old rats and lowest in the rats aged 52 weeks. The levels of most of the enzymes measured were lowest in the 6- and 52-week-old animals. No significant differences in microsomal protein, cytochrome P450, epoxide hydrolase, UDPGA transferase, or glutathione transferase were observed between the isolated and control animals. The stress treatment increased aryl hydrocarbon hydroxylase levels of the rats aged 6, 36, and 52 weeks by 100%, 50%, and 33% respectively. The microsomes prepared from livers of isolated 6-week-old animals catalyzed the binding of significantly higher amounts of [3H]-benzo(a)pyrene to DNA than controls.
    Drug Development Research 10/2004; 1(3):235 - 240. · 0.87 Impact Factor
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    ABSTRACT: Double blind, partial crossover. To evaluate the analgesic activity of a novel cranial electrostimulus in people with spinal cord injury (SCI). Hereward College, a residential centre that provides educational facilities for students with disabilities. Subjects with SCI experiencing chronic pain were randomly assigned into two groups, one of which received sham and the other transcranial electrostimulation treatment (TCET) on two occasions daily for four successive days. After a 'wash-out' period of 8 weeks all subjects returned and received the identical stimulus that the treated cohort received on the first arm of the study. Pain measurements applied before and after each session indicated that the pain decreased in the treated group to 51% of that reported at the commencement of treatment; reported pain intensity did not decrease significantly in the sham treated subjects. The same (sham) subject group reported experiencing 59% of the pain at the end of the second arm of the study (TCET) as on the first arm (sham). No significant differences were determined between the mood of all subjects estimated before and after each sham or TCET treatment session. The reported analgesic, and combined antidepressant and anxiolytic drug use in subjects receiving TCET on the second arm of the study, was 46% and 53% respectively of the average pre-study drug use. No similar decrease in the use of the drugs was noted in the same subjects after sham treatment on the first arm of the study. Salivary cortisol determinations made prior to and after each sham and treatment session implicated this corticoid in the pain-relieving mode of action of the treatment, but could not be associated with any changes in mood. Subjects receiving TCET had significantly higher urinary 3-methoxy-4-hydroxy-phenylglycol (MHPG) output after the TCET treatment period than sham stimulation, implicating increased central noradrenaline (NA) metabolism in the observed effects. The subjects reported less pain during, and immediately after receiving this transcranial treatment, although they were using less medication than when receiving sham treatment.
    Spinal Cord 03/2003; 41(2):109-17. · 1.90 Impact Factor
  • Electromagnetic Biology and Medicine - ELECTROMAGN BIOL MED. 01/1989; 8(1):59-71.
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    I D Capel, H M Dorrell
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    ABSTRACT: The concentration of lipoperoxides (estimated as thiobarbituric acid-reactive material) and some components of the antioxidant defence system have been compared in various tissues of lean and congenitally obese mice. NADPH-stimulated lipoperoxide generation in vitro was significantly higher in microsomes (microsomal fractions) prepared from obese hepatic tissue than lean. Plasma, liver and brain lipoperoxide concentration was significantly higher in obese mice. In blood derived from obese mice the concentration of non-enzymic antioxidants including caeruloplasmin and vitamin A was higher, but hepatic retinol concentration was lower in these animals. In all the tissues assayed the glutathione peroxidase activity against H2O2 was less than its activity against cumene hydroperoxide. Assayed with either substrate, glutathione peroxidase activity was significantly higher in the brain and blood of obese mice than their lean counterparts. Conversely, liver glutathione peroxidase was decreased in obese animals, representing 43% of the activity of the lean-mouse liver enzyme against H2O2 and 81% of the cumene hydroperoxide-reducing activity. The liver of obese mice had significantly less, and the kidneys more, oxidized glutathione than the corresponding tissues of lean mice. Further investigations on hepatic tissue indicated that glutathione reductase activity was lower in the obese animals, but there was no significant difference between glucose-6-phosphate dehydrogenase activity in obese and lean mice.
    Biochemical Journal 05/1984; 219(1):41-9. · 4.65 Impact Factor
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    ABSTRACT: Rats of various ages were subjected to stress by confinement in restraining cages at 2-4 degrees C. Analysis of the plasma of these animals revealed an elevation in corticosteroids of approximately 50% above the control level. The livers of all the groups of cold-restrained animals contained significantly more lipoperoxide (estimated as thiobarbituric-acid-reactive material) than did control hepatic tissue. The plasma of the 12-, 24-, and 32-wk-old groups of rats subjected to stressful treatment also contained significantly higher lipoperoxide levels. There was no significant difference between the lipoperoxide levels of the brain tissue of control or stress-treated rats. The activities of both glutathione peroxidase and glutathione reductase were increased in hepatic, but not brain, tissue of the stressed animals. The perturbation of the activities of these enzymes did not produce any significant change in the ratio of reduced, oxidized glutathione. The livers of the stressed animals had significantly less total glutathione than those of the controls.
    Journal of Toxicology and Environmental Health 04/1983; 11(3):425-36. · 1.81 Impact Factor
  • I D Capel, D Leach, H M Dorrell
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    ABSTRACT: The administration of either 5-fluorouracil, methotrexate, cyclophosphamide or vincristine to rats produced an increase in liver and plasma, but not brain, lipoperoxide levels. There was no significant difference between the glutathione peroxidase activity in the liver and the brain tissue of cytotoxic drug-treated and control rats. Glutathione peroxidase activity was significantly lower in the erythrocytes of 5-fluorouracil-and methotrexate-treated rats than in control animals. The erythrocyte glutathione peroxidase levels of vincristine- and cisplatin-treated rats did not differ significantly from the control levels. Rats which received vitamin E supplementation concomitantly with 5-fluorouracil treatment had liver and plasma lipoperoxide levels which were significantly lower than those which had received only the anticancer drug. The tissue lipoperoxide levels in the vitamin E supplemented, 5-fluorouracil-treated rats were comparable with those of arachis oil-treated controls.
    Anticancer research 01/1983; 3(1):59-62. · 1.71 Impact Factor
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    ABSTRACT: The levels of copper, zinc, calcium, manganese and magnesium have been monitored in the sera of patients suffering from various types of cancer. Only serum copper appeared to be of any diagnostic significance, its levels being above the normal reported range in the breast cancer, leukaemia and Hodgkin's lymphoma patients. In the case of breast cancer, serum copper is progressively elevated according to the stage of the disease. Serum calcium levels were also significantly lower in patients with tumours of the breast, gastrointestinal tract and cervix. The results suggest that serum copper levels could be of prognostic significance in breast cancer patients receiving radiotherapy.
    Oncology 02/1982; 39(1):38-41. · 2.17 Impact Factor
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    ABSTRACT: Electrostimulation (ES) of slow (SF, 10 Hz) or fast (FF, 500 Hz) frequency decreases the sleeping time of rats anaesthetized by administration of acute doses of hexobarbital. When ES is applied via the ears, both SF and FF are equally efficient in reducing the loss of righting reflex (LRR), whereas if ES is applied peripherally via the paws, only FF decreases the acute narcosis time. Applied cranially, either continuous stimulation or administration of intermittent current (5 minutes on and off) were equally effective in reducing narcosis. A decreased period of 30 minutes' continuous stimulation will reduce sleeping time only if administered immediately after LRR. When restrained animals received ES for periods of up to 3 hours prior to administration of the barbiturate, the sleeping time of the stimulated and sham treated animals were not significantly different.
    Acupuncture & electro-therapeutics research 02/1982; 7(1):17-26. · 0.74 Impact Factor
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    ABSTRACT: Serum galactosyl transferase was significantly higher in patients with various types of cancer than in age-matched controls. The highest serum enzyme levels were observed in the breast and respiratory cancer, followed by ovarian and gastrointestinal tumours; whereas the enzyme activity in prostatic cancer patients was not significantly higher than in the control subjects. In the cancer patients the serum levels of this enzyme were not significantly higher in the presence of metastases. In terminally ill patients, the serum enzyme activity decreased proportionately in accordance with the progression of their disease.
    Oncology 02/1982; 39(4):193-6. · 2.17 Impact Factor
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    ABSTRACT: Women using oral contraceptives have higher erythrocyte glutathione peroxidase levels than either pre-menopausal or post-menopausal non-oral contraceptive users. The levels of this enzyme were highest in the subjects who had been using these contraceptives for the longest periods of time. The increased enzyme levels were not the result of increased selenium or pyridoxal levels since there was no significant difference between the trace element and vitamin levels in contraceptive users and non-users. Subjects who had been using oral contraceptives had lower erythrocyte riboflavin status. This was assessed by the glutathione reductase test and was lower in the women who had been using oral contraceptives for the longest periods of time. A direct linear correlation between riboflavin status and glutathione peroxidase levels was observed. The most commonly used types of oral contraceptive in this study were of ethinyloestradiol-levonorgestrel formation, but it appeared that all the steroids investigated had produced statistically significant elevations in glutathione peroxidase after more than seven months usage. The possible significance of the elevation of this enzyme is discussed.
    Journal of Steroid Biochemistry 09/1981; 14(8):729-32.
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    ABSTRACT: Hair from dyslexic children, analyzed by flameless atomic absorption spectrometry, showed significantly higher concentrations of magnesium and copper than did hair from control subjects. The hair from dyslexic children also contained significantly higher concentrations of aluminum and cadmium than that from control children; the cadmium concentration exceeded the normal acceptable range. There were no significant differences in the case of lead, calcium, selenium, or mercury. Our results indicate that excessive cadmium burden could be implicated in this form of learning disorder.
    Clinical Chemistry 07/1981; 27(6):879-81. · 7.15 Impact Factor
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    ABSTRACT: Treatment of C57/BL mice with either cisplatin or gallium nitrate inhibited the growth and metastasis of the Lewis lung tumour and these anti-tumour agents also lowered the zinc levels of some tissues. Nutritional zinc deficiency or the deficiency arising from treatment with the chelating agent, penicillamine, also restricted tumour growth. Although the anti-tumour activity of cisplatin was enhanced in zinc-deficient mice, many of these animals died before sacrifice 14 days after tumour inoculation. The results indicate that zinc status could have considerable bearing on the therapeutic index of the mental-containing anti-cancer drugs.
    Anticancer research 02/1981; 1(5):269-73. · 1.71 Impact Factor
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    ABSTRACT: Rats were subjected to various forms of treatment in the manner likely to induce gastrointestinal insult. These and control animals were sacrificed and, using inverted sacs, the rate of absorption of either dimethylnitrosamine and benzo(a)pyrene determined. The gastrointestinal injury resulting from the differing treatments did not significantly affect the absorption of benzo(a)pyrene, whereas that of dimethylnitrosamine was significantly increased after each incubation time, most notably by alcohol pretreatment. The results demonstrate that intestinal damage increases the absorption of some carcinogens.
    Oncology 02/1981; 38(4):243-8. · 2.17 Impact Factor
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    ABSTRACT: Rats were subjected to stress by increasing the number in a cage from 6 to 40 for 6-hr periods for either 2, 4, or 8 days. This treatment produced a rise in serum corticosteroid level which reached a maximum on the fourth day of treatment. The plasma elimination rate of antipyrine was not significantly altered in the stressed animals although the rate of absorption of the drug was decreased. Microsomes prepared from the livers of stressed and control animals indicated that the treatment had differing effects on some of the enzymes responsible for the metabolism of the carcinogen benzo[a]pyrene. Thus, uridine diphosphoglucuronic acid (UDPGA) transferase activity was significantly decreased, aryl hydrocarbon hydroxylase (AHH) and epoxide hydratase (EH) activities were increased, but cytochrome P-450 and glutathione transferase levels in the hepatic microsomes from the treated animals did not differ significantly from those of the controls. The microsome-catalyzed binding of benzo[a]pyrene to DNA was significantly reduced by this stress treatment.
    Environmental Research 11/1980; 23(1):162-9. · 3.24 Impact Factor
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    ABSTRACT: Rats were subjected to stress by isolation for periods of up to eight days, which produced an elevation in plasma cortisol. In vivo drug metabolism as estimated by the plasma elimination rate of orally-administered antipyrine was not significantly affected by this treatment although there was an apparent decrease in the absorption rate of the drug. In vitro experiments on hepatic microsomal preparations derived from stressed animals indicate that this stress increased in the activity of some enzyme systems concerned with benzo(a)pyrene activation and this correlated with an increased binding of the carcinogen to DNA. The activity of conjugating enzyme which could catalyze the excretion of such carcinogens was not significantly altered. The results indicated that stress could have an important bearing on carcinogenesis by enhancing to a greater extent enzyme systems responsible for activation than those involved in the excretion of polycyclic aromatic hydrocarbons.
    Journal of environmental pathology and toxicology 10/1980; 4(2-3):337-44.
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    ABSTRACT: The effect of ingestion of water containing 1 or 10% ethanol for a period of four weeks on serum vitamin E, hepatic glutathione peroxidase, erythrocyte-glutathione peroxidase, glutathione transferase, Superoxide dismutase and selenium has been investigated in rats. The serum levels of total and free vitamin E were not significantly affected by ethanol ingestion at either level. The level of erythrocyte glutathione peroxidase was decreased to 43 or 28 per cent of the control level by intake of either 1 or 10% ethanol solution, respectively, whilst there was no alteration in glutathione transferase activity. Ethanol treatment did not alter erythrocyte selenium levels or Superoxide dismutase activity. Hepatic glutathione peroxidase activity was increased to approximately 166 per cent of the control value by either 1 or 10% ethanol ingestion. The results indicate that the activity of the enzyme principally involved in preventing lipohydroperoxide-induced haemolysis is significantly reduced by ethanol ingestion.
    Biochemical Pharmacology 07/1980; 29(12):1737-9. · 4.58 Impact Factor