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Biomedical subjects

P Giles

Publications and source records attributed to P Giles.

11 recordsLinked to original sources
PubMed2001

Gender may affect the action of garlic oil on plasma cholesterol and glucose levels of normal subjects.

Early trials of garlic preparations on blood lipids mainly supported a lipid-lowering effect, whereas later well-designed garlic tablet trials were mainly entirely null. However, enteric simulation tests suggest that this discordance may result from ineffective delivery of bioactive agents from the brands of garlic powder (GP) and cyclodextrin-bound garlic oil (GO) tablets tested in some recent negative trials. In contrast, enteric simulation tests show that the preformed bioactive agents present in "traditional" gelatin capsules of GO are efficiently released, although such capsules have rarely been investigated in lipid-lowering trials. It was hypothesized that gelatin capsules of GO given to normal subjects would improve specified coronary heart disease risk factors. Effects of a GP preparation were also investigated. Subjects (n = 51; men and women, mean age 27 y) were randomly assigned to receive either 8.2 mg/d of GO (allyl sulfides) or placebo for 11 wk. Another 27 subjects received garlic powder (GP) of similar biopotential (7.8 mg allicin/d). Outcome measures were 95% confidence intervals (CI) between GO and placebo groups for differences between baseline and subsequent sample times. Men and women combined showed no significant differences save for an improved total antioxidant capacity at 6 wk (P = 0.01). Hence, no benefit from GO after 11 wk is one plausible conclusion. However, there were significant differences in effect of GO between men and women for HDL cholesterol (HDL-C) (P = 0.004) and total cholesterol (TC)/HDL-C (P = 0.003). Women showed favorable effects in terms of CHD risk factors (i.e., increases in HDL-C and reductions in TC/HDL-C), whereas men had small adverse effects. There was a significant difference in the GO effect for glucose (P = 0.006), with a reduction seen for men and an increase for women. The gender effects were unexpected and such analyses were not planned in advance. Confirmation of these findings with larger numbers of subjects would have importance for the use of garlic against CHD and for the design of future garlic studies.

Adult↗
PubMed2001

A randomized trial of the effects of garlic oil upon coronary heart disease risk factors in trained male runners.

Most trials of bulb garlic and garlic powder tablets indicate reduced coronary heart disease (CHD) risk in elevated-risk subjects. Most persons taking garlic supplements lack overt risk of CHD. However, no trials have tested steam-distilled garlic oil (GO) capsules with healthy subjects. The objectives of the present randomized, double-blind, placebo-controlled study were to determine whether GO capsules reduce CHD risk in trained male runners. Twenty-seven volunteers (mean age, 28.8 years) completed the study. Each took 12.3 mg/day GO (or placebo) capsules for 16 weeks. Main outcome measures were 95% confidence intervals (CIs) between GO and placebo groups for differences in changes of blood pressure (BP), plasma lipids, total antioxidant status (TAS), low-density lipoprotein (LDL) composition and blood clotting factors. Principal results as mean differences (95% CI) between GO and placebo are: pulse, 2.9 beats/min (-0.8 to 6.7), P = 0.12; systolic BP, -4.5 mmHg (-10.8 to 1.9), P = 0.16; plasma total cholesterol, 0.01 mmol/l (-0.34 to 0.37), P = 0.95; plasma triglycerides, -0.20 mmol/l (-0.43 to 0.03), P = 0.09; plasma TAS, 45 micromol Trolox equivalent/l (-35 to 124), P = 0.26; LDL density, 0.0019 g/ml (-0.0005 to 0.0043), P = 0.12; LDL triglycerides/protein, -0.078 mg/mg (-0.149 to -0.007), P = 0.03; LDL cholesterol/protein, -0.24 mg/mg (-0.69 to 0.22), P = 0.3; LDL TAS/triglycerides, 29 nmol/mg (11, 68), P = 0.15; prothrombin time, 0.99 s (-0.36 to 2.35), P = 0.14; partial thromboplastin time, 3.0 s (-1.0 to 7.1), P = 0.13. Results were null statistically. Trends with GO were mostly towards lower CHD risk, and a larger study (approximately 150 subjects) is required to test their validity.

Adolescent↗
PubMed1995

The pharmacokinetics of aminoguanidine in end-stage renal disease patients on hemodialysis.

Aminoguanidine is an investigational agent that may slow or prevent many diabetes-related complications. Since the elimination of aminoguanidine is dependent on renal function, its pharmacokinetics was investigated in eight chronic renal failure patients maintained on hemodialysis. Each patient received 300 mg of aminoguanidine hydrochloride during both an interdialytic and an intradialytic period. During the interdialytic period, the maximum aminoguanidine concentration (Cmax) and time to reach Cmax was 4.5 micrograms/mL and 1.5 hours, respectively. The terminal elimination half-life in these patients was prolonged (37.9 hours). The renal clearance was 2.1 mL/min. Only 8.7% of the administered dose was recovered unchanged in the urine, which is markedly reduced from what is recovered in urine in subjects with normal renal function. There was a positive correlation between the renal clearance of aminoguanidine and the patients' residual renal function (P < 0.05). During hemodialysis, the half-life of aminoguanidine was shortened to 3.9 hours. The hemodialysis clearance of aminoguanidine was 203.6 mL/min. After cessation of hemodialysis, a significant rebound in plasma aminoguanidine concentrations (mean, 39%) was observed. Thus, the dose of aminoguanidine hydrochloride will need to be significantly reduced in patients with end-stage renal disease. Given the interdialytic and intradialytic pharmacokinetics of aminoguanidine, three times weekly dosing after each hemodialysis session is suggested.

Diabetic Nephropathies↗
PubMed1995

Khat chewing delays gastric emptying of a semi-solid meal.

BACKGROUND: The leaves of Khat are chewed for their central stimulant effect, but their use may cause anorexia and constipation. METHODS: Gastric emptying of a radio-labelled semi-solid meal was measured in 12 healthy volunteers on two occasions a week apart. Subjects chewed either Khat leaves (Catha edulis) or lettuce for 2 h before the study. RESULTS: Gastric emptying was significantly (P < 0.02) prolonged after chewing Khat compared with lettuce. CONCLUSION: The sympathomimetic action of cathinone in Khat may cause the observed delay in gastric emptying.

Adult↗
PubMed1993

Funding for research.

With the exception of pharmaceutical companies, all the funding organisations have a standard application and information form outlining the areas of research they wish to encourage and fund. Many of the organisations advertise nationally, indicating closing dates and contact numbers for further information. It is important to contact fund administrations to gain feedback on the direction of your project while it is still being drafted. This article has nominated just a few of the funding sources available to general practice related researchers. It is simply a matter of becoming familiar with the variety of sources and the types of projects that they fund. By applying only to common knowledge sources such as GPEP, researchers are ignoring the availability of alternate funding sources that may be even more appropriate to their project.

Australia↗
PubMed1985

Inhibition of Chlamydia trachomatis growth in McCoy, HeLa, and human prostate cells by zinc.

Zinc salts (10(-4) and 10(-5) M) inhibited the number of Chlamydia trachomatis inclusions in McCoy, HeLa, and primary human prostate epithelial cell cultures. Addition of zinc salts 1 h before or 24 h after inoculation with C. trachomatis was found to inhibit growth. Both C. trachomatis serotype D and a lymphogranuloma venereum strain were inhibited by the zinc salts. Although the mechanism of inhibition is not known, the continued presence of the zinc appeared necessary for maximal effect. At the concentrations tested, zinc was not directly toxic to the McCoy cells. These results suggest that the levels of zinc in prostatic secretions may be sufficient to preclude the recovery of chlamydia in the diagnostic laboratory or to inhibit chlamydia from infecting the prostate in vivo.

Cell Line↗
PubMed1984

Carnitine as a possible adjunct in parenteral feeding.

Carnitine is necessary for the transport of fatty acids across the inner mitochondrial membrane, and depletion in response to Intralipid infusion has previously been demonstrated. This study investigates whether orally administered L-carnitine increases tolerance to a lipid load given intravenously. Eight patients with active inflammatory bowel disease, being treated with intravenous prednisolone, were studied. Intralipid was infused on two occasions. Triglycerides and ketone bodies rose in a reproducible manner. Carnitine did not influence these changes. Carnitine excretion rose after an oral dose indicating that carnitine was absorbed, but carnitine excretion was increased in the steroid-treated individuals and rose after oral prednisolone in two healthy subjects. It is concluded that under the conditions of this study oral carnitine is without demonstrable effect on the handling of an intravenous lipid load.

Journal Article↗