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Biomedical subjects

P Dhillon

Publications and source records attributed to P Dhillon.

9 recordsLinked to original sources
PubMed2004

Bilateral responses of upper limb muscles to transcranial magnetic stimulation in human subjects.

Anatomical and behavioural work on primates has shown bilateral innervation of axial and proximal limb muscles, and contralateral control of distal limb muscles. The following study examined if a clear boundary exists between the distal and proximal upper limb muscles that are controlled contralaterally or bilaterally. The right motor cortical area representing the upper limb was stimulated, while surface EMG was recorded bilaterally from various upper limb muscles during rest and phasic voluntary contractions. Peak-to-peak amplitude of motor evoked potential (MEP) was measured for each muscle on both sides. The ratio R = (ipsilateral MEP: contralateral MEP) was calculated for seven pairs of muscles. For each of the seven pairs, R was less than 1.0, implying that for each muscle and subject, the contralateral control is stronger. The boundary where R changed from almost zero to a clearly measurable magnitude depended on the subject. Ipsilateral MEPs from trapezius and pectoralis could be recorded with a small background contraction from almost all subjects; on the other hand, in deltoid and biceps brachii, ipsilateral MEPs were observed only with bimanual phasic contractions. The forearm and hand muscles, in general, did not show any ipsilateral MEPs. Major differences between subjects lay in the presence or the absence of ipsilateral MEPs in biceps brachii and deltoid, without defining a sharp boundary between proximal and distal muscles.

Adult↗
PubMed2000

Interactions of bacterial cationic peptide antibiotics with outer and cytoplasmic membranes of Pseudomonas aeruginosa.

Polymyxins B and E1 and gramicidin S are bacterium-derived cationic antimicrobial peptides. The polymyxins were more potent than gramicidin S against Pseudomonas aeruginosa, with MICs of 0.125 to 0. 25 and 8 microg/ml, respectively. These peptides differed in their affinities for binding to lipopolysaccharide, but all were able to permeabilize the outer membrane of wild-type P. aeruginosa PAO1 strain H103, suggesting differences in their mechanisms of self-promoted uptake. Gramicidin S caused rapid depolarization of the bacterial cytoplasmic membrane at concentrations at which no killing was observed within 30 min, whereas, conversely, the concentrations of the polymyxins that resulted in rapid killing resulted in minimal depolarization. These data indicate that the depolarization of the cytoplasmic membrane by these peptides did not correlate with bacterial cell lethality.

Anti-Bacterial Agents↗
PubMed1996

Immunological cross-reactivity between salivary gland proteins of Hyalomma anatolicum anatolicum and Boophilus microplus ticks.

Immunological cross-reactivity was established between salivary gland extract antigens of Hyalomma anatolicum anatolicum (H.a.a) and Boophilus microplus (B.m.), using native-polyacrylamide gel electrophoresis (native-PAGE), immunoblotting, DOT-enzyme immunoassay (DOT-EIA) and in vivo intra-dermal skin test revealing immediate type hypersensitivity swelling reaction. Native-PAGE revealed six proteins in common of molecular weights of 60, 66, 148, 264, 300 and > 300 kDa in the salivary gland extract (SGE) of both the ticks. Four additional bands of molecular weights of 56, 64, 120 and 220 kDa were present in H.a.a. but absent in B.m. Immunoblot assay of native-PAGE transblotted proteins of H.a.a., using mice anti-H.a.a. SGE and anti-B.m. SGE immune serum revealed a common protein of 66 kDa. In DOT-EIA, anti-H.a.a. or anti-B.m. SGE immune serum gave similar antibody titres against the SGE antigens of either tick species. Intradermal inoculation of the SGE antigens of either species on cross-bred calves (Bos indicus x Bos taurus) immunized to H.a.a. or B.m. ticks produced a strong, immediately hypersensitivity skin swelling reaction.

Animals↗
PubMed1994

The effect of the orally active platelet-activating factor antagonist WEB 2086 in the treatment of asthma.

Platelet-activating factor (PAF) may be a major mediator of asthma and bronchial hyperreactivity through its many proinflammatory actions. Specific antagonism of PAF might offer an alternative anti-inflammatory treatment to inhaled corticosteroids. To test this, we have studied the effect of an orally active PAF antagonist, WEB 2086, on the inhaled steroid requirements of symptomatic atopic asthmatics in a double-blind randomized placebo-controlled parallel group study. The inhaled corticosteroid dose required for symptomatic control of asthma was established and further steroid reduction was attempted after treatment with WEB 2086 40 mg three times daily for 12 wk. Of 106 patients recruited, 68 entered the treatment phase and 65 completed 6 wk of treatment. The mean daily corticosteroid dose (SE) at study entry was 1,257 (75) micrograms which was reduced by 323 (66) micrograms during the run-in period without loss of symptomatic control. A further 416 (57) micrograms reduction in inhaled corticosteroid dosage was possible during the treatment phase but this was almost identical in the WEB 2086 and placebo-treated groups, amounting to 353 (92) and 481 (65) micrograms/day respectively (not significant [NS]). Rate of relapse following corticosteroid reduction was a continuous variable and relapse occurred at different times depending on the variable used to define it. Time to relapse measured by an increase in symptoms correlated with disease duration (r = 0.41, p < 0.01) and with the dose of inhaled corticosteroid at study entry (r = 0.36, p < 0.01) but no other measured variable predicted the time to relapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1979

Double-blind trial of the use of transfer factor in the treatment of Crohn's disease.

We have undertaken a double-blind controlled trial of the use of transfer factor in Crohn's disease. Thirty-three patients with known Crohn's disease completed the trial in which half the patients had three injections of transfer factor and the other half were given saline. After six months there was no significant difference in the clinical condition of either of the two groups compared with before receiving treatment. There was also no difference in their in vitro lymphocyte function, although a number of patients exhibited altered responsiveness to skin testing with tuberculin or streptokinase/streptodornase. A signficant fall on Crohn's disease activity index score occurred over the initial 'acclimatising period' before the trial was started, probably related to overcoming initial introspection and the placebo effect of being part of a trial.

Adult↗