PubMed Health⌕ Search

Biomedical subjects

G McKillop

Publications and source records attributed to G McKillop.

16 recordsLinked to original sources
PubMed2000

Colour Doppler imaging of the ocular circulation in diabetic retinopathy.

PURPOSE: To measure blood flow velocity in the ophthalmic artery (OA) and central retinal artery (CRA) in patients with diabetic retinopathy. SUBJECTS AND METHODS: 62 age-matched subjects divided into 3 groups: nondiabetic controls (n=17); diabetics with no clinical retinopathy or background changes (n=24); diabetics with either pre-proliferative or proliferative retinopathy (n=21). Colour Doppler imaging was performed on supine patients by one masked observer using the Acuson 128 machine. RESULTS: There was a statistically significant (p<0.05) decrease in both the peak systolic velocity (PSV 0.073 m/s) and end diastolic velocity (EDV 0.014 m/s) of the central retinal artery in the pre-proliferative/proliferative group compared to the no retinopathy/background retinopathy group (PSV 0.096 m/s, EDV 0.024 m/s) and the control group (PSV 0.142 m/s, EDV 0.029 m/s). The resistance index of the ophthalmic artery was significantly increased in both the preproliferative/proliferative (0.81) and the no retinopathy/background group (0.81) compared to controls (0.72). CONCLUSION: Reduced blood flow velocity was found in the CRA of diabetic patients and appeared to become further reduced with the progression of retinopathy. This suggests that monitoring with Colour Doppler imaging may have predictive power in identifying those at greatest risk of developing sight threatening proliferative disease. The resistance index of the OA was increased in diabetics compared to controls.

Aged↗
PubMed1997

Color Doppler imaging in untreated high- and normal-pressure open-angle glaucoma.

PURPOSE: To evaluate ocular blood flow velocity indices in untreated primary open-angle glaucoma (POAG) and normal pressure glaucoma (NPG). METHODS: Twenty-five untreated patients with NPG, 23 untreated patients with POAG, and 26 age-matched normal control subjects underwent color Doppler imaging for the measurement of blood flow velocity in the central retinal and ophthalmic arteries. Neither the patients nor the control subjects were using systemic beta-blockers or calcium channel blockers. After log transformation of non-normal data, group differences were compared with a one-way analysis of variance followed by unpaired t-test with the Bonferroni correction. Statistical significance was set at P < 0.05. RESULTS: The central retinal artery end diastolic velocity was significantly lower in patients with POAG than in normal subjects. The ophthalmic artery peak systolic velocity (PSV) was significantly greater in patients with POAG than in those with NPG and normal subjects. The resistance index (RI) of both the ophthalmic and central retinal arteries was significantly greater in patients with POAG than in normal subjects, and the central retinal artery RI was significantly greater in those with NPG than in normal subjects. Systemic pulse pressure and systolic blood pressure were significantly greater in patients with POAG compared with normal subjects. Multiple regression analysis showed a significant relation between ophthalmic artery PSV and intraocular pressure (but not with any of the cardiovascular parameters) in the POAG group. Chi-square analysis found significantly more systemic vascular disease in patients with NPG and POAG compared with that of normal subjects. CONCLUSIONS: There was an increased resistance to blood flow in the central retinal artery of untreated patients with NPG and POAG and also in the ophthalmic artery of patients with POAG. The ophthalmic artery peak systolic velocity was elevated in untreated patients with POAG. Altered ocular circulation (with different patterns of presentation) appears to be common to patients with NPG and patients with POAG.

Aged↗
PubMed1996

Colour Doppler imaging in giant cell (temporal) arteritis: serial examination and comparison with non-arteritic anterior ischaemic optic neuropathy.

The ophthalmological manifestations of giant cell arteritis (GCA) present a difficult diagnostic and management problem to the ophthalmologist. The orbital circulation is frequently involved in the disease process. The effects of GCA on orbital blood flow assessed by colour Doppler imaging (CDI) were investigated in this study. Serial CDI examinations of the orbital blood vessels were performed (at presentation, 2 days, 1 week and at 1 month) on 7 patients with GCA. CDI examination at presentation was also performed on 4 patients with non-arteritic anterior ischaemic optic neuropathy (AION) for comparison. Blood flow could not be detected in up to three arteries in the affected (ipsilateral) orbit of 6 GCA patients at presentation. Five of these patients were also found to have undetectable blood flow in the posterior ciliary arteries of the contralateral orbit. Serial CDI examination revealed blood flow alterations in arteritic patients despite treatment. Return of blood flow to normal was slow, and related to the clinical features. By contrast, only 1 of the patients with non-arteritic AION showed undetectable blood flow in a posterior ciliary artery. GCA leads to widespread and prolonged alterations in orbital blood flow. CDI allows the detection and monitoring of such alterations in orbital blood flow, which correlate with the clinical features of GCA. Serial CDI examinations in GCA may be used to aid management decisions.

Aged↗
PubMed1995

Measurement of ocular blood flow velocity using colour Doppler imaging in low tension glaucoma.

The purpose of this study was to compare the velocity of blood flow and vascular resistance measured by colour Doppler imaging in the ophthalmic and central retinal arteries in 34 eyes of 34 patients (mean age 68.1 years) with low tension glaucoma (LTG) and 17 eyes of 17 age-matched normal controls (mean age 65.2 years). The Acuson 128 machine (using a 7.5 MHz probe) was used to measure peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistive index (RI). The EDV of the ophthalmic artery (OA) in the LTG was significantly (p = 0.04) less than in the normal control group. There was a significant (p = 0.02) increase in the vascular RI of both the OA and central retinal artery in the LTG group compared with the normal controls. The OA RI increased with age (r = 0.61, p = 0.0001), and the OA EDV decreased with age (r = -0.50, p = 0.003), in the LTG group but not in the normal control group. The results suggest an increased resistance to blood flow in the ophthalmic and central retinal arteries of LTG patients.

Aged↗
PubMed1992

Color Doppler ultrasound of orbital and optic nerve blood flow: effects of posture and timolol 0.5%.

Color Doppler ultrasound allows simultaneous imaging with real-time ultrasound and superimposed color-coded vascular flow, allowing visualization of vessels previously beyond the resolution of conventional imaging, such as those in the orbit. With this technique, 20 healthy volunteers were studied. Three regional vessels named 1, 2, and 3 were identified. No significant difference in maximum or minimum blood velocity or resistive index was detected between vessels 1 and 2, although significant differences were noted between both these vessels and vessel 3 (P less than 0.01 and P less than 0.001, respectively). These regional variations are unaffected by small but significant rises in pulse (P less than 0.05) and diastolic blood pressure (P less than 0.01) induced by postural change. No significant change within each vessel was recorded in response to posture, reflecting autoregulation within these vessels. Using a similar technique, 10 healthy volunteers were studied at baseline and at 2 hr and 3 d following the unilateral instillation of 0.5% timolol eye drops. A fall in resistive index was recorded in vessel 3 for both eyes (P less than 0.05, timolol administered eye; P less than 0.01 timolol-free eye). This effect was independent of any simultaneous fall in intraocular pressure that occurred only in the eye receiving timolol drops (P less than 0.01). These results support the presence of B receptors in the vessels at the optic nerve head (vessel 3). A fall in resistive index should not compromise the blood supply in this region, and may even increase it.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1990

The effect of habitual sustained endurance exercise on cardiac structure and function.

We performed echocardiographic evaluation of 20 male veteran endurance runners (mean age 56 +/- 7 years) and compared them with a group of age-matched controls. All the runners had run at least 25 miles per week for more than 25 years. Although only four athletes showed voltage ECG evidence of left ventricular hypertrophy, using echocardiography, 10 athletes had evidence of left ventricular hypertrophy. Thus electrocardiography is insufficiently sensitive to detect LVH in this group (10%). Left ventricular posterior wall thickness and left ventricular mass were significantly greater in the athletes, the difference becoming more marked when LV mass was corrected for body surface area and, consequently, the wall thickness: cavity diameter ratio was increased (P less than 0.04). There was no difference between the two groups in left ventricular performance and no correlation between left ventricular mass and running ability. Thus, veteran runners develop structural cardiac changes similar to younger power-trained athletes and do not show characteristics normally expected of 'volume overload' which is thought to occur in running.

Blood Pressure↗
PubMed1987

Lipoprotein analysis in bodybuilders.

The use of anabolic steroids to augment athletic performance is widespread. It is known that these drugs can adversely affect lipoproteins in normal volunteers, leading to increased cholesterol and low density lipoprotein and depressed high density lipoprotein. It has been shown that endurance type exercise can lead to beneficial effects on lipoproteins but the effects of power exercise are less clear-cut and made more difficult to interpret by prior anabolic steroid use. This paper details the lipoprotein results in 24 subjects, eight sedentary controls, eight non-steroid and eight steroid using bodybuilders. The results revealed no significant difference between sedentary controls and non-steroid bodybuilders suggesting that this form of training does not cause beneficial effects on lipoproteins. However, the steroid-using groups had higher cholesterol and low density lipoprotein, with lower high density lipoprotein, high density lipoprotein2, high density lipoprotein3 and high density lipoprotein2/high density lipoprotein3 ratios compared to the other two groups. The long-term effects of such results may be an increased risk of atherosclerosis and requires long-term follow-up.

Adult↗
PubMed1987

Drug abuse in body builders in the West of Scotland.

Forty one amateur body builders in a West of Scotland gymnasium were questioned about body building drug usage during the period January 1984 to January 1985. Eight out of 41 (19.5%) had used drugs to enhance their physique and performance. Anabolic and androgenic agents were mainly used but diuretics, thyroxine and human chorionic gonadotrophin were also used. Those who took drugs, in all cases, took combinations of drugs. Drug dosage was generally much in excess of that normally recommended, though there were no serious side effects at the time of the study. If this experience was typical nationwide it would represent a significant number of body builders abusing drugs. In no case was there any medical supervision.

Adolescent↗
PubMed1987

A case of intravenous and oral mefenamic acid poisoning.

A 22 year old heroin addict was admitted with tonic-clonic seizures, confusion and agitation 10 hours after taking mefenamic acid 5 grams orally and 2.25 grams intravenously. This appears to be the first recorded case of intravenous mefenamic acid abuse and, although not fatal, is a cause of concern. This is a commonly used drug and its seizure inducing potential is well recognised. It may therefore be worthwhile considering the possibility of intravenous abuse of mefenamic acid in heroin addicts admitted with confusion or seizures.

Administration, Oral↗
PubMed1986

Increased left ventricular mass in a bodybuilder using anabolic steroids.

As the effects of anabolic steroids on left ventricular structure and function are unknown, we carried out clinical examination, 12 lead electrocardiography and echocardiography on a 23 year old male bodybuilder using these drugs. In this subject we found values of ECG voltage criteria, left ventricular-mass, posterior wall and interventricular septal thickness which exceeded those found in normal subjects and also in other competitive, power athletes. Despite these values, however, ejection fraction remained normal. This would suggest that anabolic steroids perhaps have a direct effect on the myocardium, in addition to the effects of training, but whether this is of pathological significance is unclear.

Adult↗