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Biomedical subjects

C Carney

Publications and source records attributed to C Carney.

12 recordsLinked to original sources
PubMed2000

The mercury sphygmomanometer should be abandoned before it is proscribed.

Both in clinical practice and medical research, blood pressure is still largely measured by auscultation using a mercury sphygmomanometer. Blood pressure is the most important predictor of life expectancy. Treatment of high blood pressure reduces strokes, heart attack and heart failure. Accurate measurement is therefore essential. At a large London teaching hospital, just under 500 mercury sphygmomanometers and their associated cuffs were examined. More than half had serious problems that would have rendered them inaccurate in measuring blood pressure. At the same time, assessment of the technical knowledge needed to measure blood pressure by the ausculatory technique was also carried out amongst medical and nursing staff. This showed a considerable level of ignorance. These results inevitably lead to inaccurate measurement of blood pressure with serious consequences. In addition mercury is a non-degradable pollutant, eventually accumulating on the sea bed. The use of mercury in sphygmomanometers is already in the process of being eliminated in Scandinavia and Holland and other countries are likely to follow. Our results suggest that mercury sphygmomanometers are not adequately maintained and require expertise that is not available for accurate measurement of blood pressure. Their use should be dispensed with on these grounds before a ban for other and, perhaps less justifiable reasons. Validated automatic devices, which are less liable to measurement and observer error should be used instead. At the same time a concerted effort is needed to instruct health care professionals on the importance of more accurate measurement of blood pressure. Journal of Human Hypertension (2000) 14, 31-36.

Adult↗
PubMed1999

Conjugal loss and syndromal depression in a sample of elders aged 70 years or older.

OBJECTIVE: The goal of this study was to describe the association between conjugal loss and both syndromal depression and depressive symptoms in a prospective cohort study of people aged 70 years or older. METHOD: A measure of syndromal depression, the shortform Composite International Diagnostic Interview (CIDI), and a revised version of the Center for Epidemiologic Studies--Depression Scale (CES-D Scale) were administered to a group of 5,449 elders in a longitudinal cohort study. The authors compared the rates of syndromal depression (CIDI diagnosis) and depressive symptoms (six CES-D Scale symptoms) in married participants and those who lost spouses between the first and second waves of assessment. RESULTS: The rate of syndromal depression in the newly bereaved was nearly nine times as high as the rate for married individuals, and the rate of depressive symptoms was nearly four times as high. The percentage of the bereaved respondents who had scores above threshold on the revised CES-D Scale was higher for those interviewed up to 2 years after loss of a spouse than for married respondents. Age, sex, prior psychiatric history, and the expectedness of the death did not differ between depressed and nondepressed newly bereaved subjects. CONCLUSIONS: Recent bereavement is a significant risk factor for syndromal depression in the elderly. Some widows and widowers experienced high levels of depressive symptoms up to 2 years after the loss of their spouses. Neither demographic variables nor variables concerning the nature of the spouse's death predicted bereavement-related depression.

Age Factors↗
PubMed1999

BDNF and NT4/5 promote survival and neurite outgrowth of pontocerebellar mossy fiber neurons.

The neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3), and NT4/5 are all found in the developing cerebellum. Granule cells, the major target neurons of mossy fibers, express BDNF during mossy fiber synaptogenesis. To determine whether neurotrophins contribute to the development of cerebellar afferent axons, we characterized the effects of neurotrophins on the growth of mossy fiber neurons from mice and rats in vitro. For a mossy fiber source, we used the basilar pontine nuclei (BPN), the major source of cerebellar mossy fibers in mammals. BDNF and NT4/5 increased BPN neuron survival, neurite outgrowth, growth cone size, and elongation rate, while neither NT3 nor NGF increased survival or outgrowth. In addition, BDNF and NT4/5 reduced the size of neurite bundles. Consistent with these effects, in situ hybridization on cultured basilar pontine neurons revealed the presence of mRNA encoding the TrkB receptor which binds both BDNF and NT4/5 with high affinity. We detected little or no message encoding the TrkC receptor which preferentially binds NT3. BDNF and NT4/5 also increased TrkB mRNA levels in BPN neurons. In addition to previously established functions as an autocrine/paracrine trophic factor for granule cells, the present results indicate that cerebellar BDNF may also act as a target-derived trophic factor for basilar pontine mossy fibers.

Afferent Pathways↗
PubMed1997

Double-blind randomised trial of modest salt restriction in older people.

BACKGROUND: Stroke is directly related to blood pressure and treatment trials in older hypertensive individuals show a reduction in strokes. However, the majority of strokes occur in normotensive individuals in whom no attempt is made to lower blood pressure. We compared the effects of modest salt restriction on blood pressure in older hypertensive and normotensive people. METHODS: 47 untreated elderly people (24 men, age range 60-78 years; blood-pressure range 123-205 mm Hg systolic and 64-112 mm Hg diastolic) completed a 2-month double-blind randomised placebo-controlled crossover study of modest salt restriction with slow sodium and placebo to give a salt intake of either 10 g (equivalent to the normal amount for the UK population) or 5 g. FINDINGS: On the normal salt intake for the UK population, supine blood pressure was 163/90 (SD 21/10) mm Hg with urinary sodium excretion of 177 (49) mmol/day. With modest sodium restriction, blood pressure fell to 156/87 (22/9) mm Hg (p < 0.001/0.004) with a urinary sodium excretion of 94 (50) mmol/day. A reduction in sodium intake of 83 mmol/day was associated with a reduction of 7.2/3.2 mm Hg. There was no significant difference in the blood-pressure fall between 18 normotensive and 29 hypertensive participants (8.2/3.9 vs 6.6/2.7 mm Hg). INTERPRETATION: A modest reduction in salt intake leads to a fall in blood pressure in both normotensive and hypertensive older people similar to that in outcome trials of thiazide-based treatment. Since the majority of strokes in older people occur below the current definition of hypertension, our results have important implications for the prevention of stroke.

Aged↗
PubMed1997

Anti-lock brake system: an assessment of training on driver effectiveness.

When activated correctly, Anti-Lock Brake Systems (ABS) can provide drivers with the ability to stop a vehicle in shorter distances and allow for more vehicle control under heavy braking than conventional brake systems. This is especially true under wet or icy road conditions. However, it is believed that many drivers are either unaware of the correct method of activation or they revert back to the old method of pumping the brakes when they are faced with a hard braking situation. This paper examines the effectiveness of implementing low-cost training methods for alerting drivers to the correct brake activation technique. A 4-page, color training pamphlet was developed and subjects were given a short period of time to read it over before being asked to drive on an icy test track. Results indicated that those subjects who received the training were able to stop in shorter distances in a straight line braking event and more often used the correct brake activation technique than those subjects who did not receive the training. However, the stopping distance benefits were not realized in the curved and surprise braking events. These results suggest that the transfer of verbal knowledge may have value as a means for solving the apparent problem of improper ABS usage. However, some additional research should be done to validate these results. Since this experiment was conducted directly after the material was read, the possibility exists that without reinforcement, the trained braking techniques might become extinct in a short period of time.

Accidents, Traffic↗
PubMed1997

Human factors field evaluation of automotive headway maintenance/collision warning devices.

Three on-road studies were conducted to determine how headway maintenance and collision warning displays influence driver behavior. Visual perspective, visual perspective with a pointer, visual perspective combined with an auditory warning, discrete visual warning, and discrete auditory warning were assessed during both coupled headway and deceleration events. Results indicate that when drivers are provided with salient visual information regarding safe headways, they utilize the information and increase their headway when appropriate. Auditory warnings were less effective than visual warnings for increasing headways but may be helpful for improving reaction time during events that require deceleration. Drivers were somewhat insensitive to false alarm rates, at least during short-term use. Finally, and most important, driver headway maintenance increased by as much as 0.5 s when the appropriate visual display was used. However, a study to investigate the longterm effects of such displays on behavior is strongly recommended prior to mass marketing of headway maintenance/collision warning devices.

Accidents, Traffic↗
PubMed1994

Platelet volume is not increased in essential hypertension.

Platelet size, a determinant of platelet function, is a newly emerging risk factor for atherothrombosis. Platelet volume has previously been shown, using less than ideal methodology, to be increased in essential hypertension. Mean platelet volume was measured in 38 patients with essential hypertension and 38 paired normotensive control subjects matched for age and sex. Platelet volume, median (interquartile ranges) 7.7 (7.2-8.5) fl vs. 7.8 (7.5-8.4) fl (2P = 0.40), platelet count 242 (220-288) x 10(9)/l vs. 243 (215-292) x 10(9)/l (2P = 0.68) and platelet mass 1.91 (1.67-2.18) ml/l vs. 1.84 (1.70-2.23) ml/l (2P = 0.90) were similar in the hypertensive patients (supine BP: SBP 168 (153-178) mmHg, DBP 103 (98-110) mmHg) and control subjects (SBP 126 (112-138) mmHg, DBP 78 (74-82) mmHg). Serum lipids and plasma glucose and creatinine concentrations were not different between the groups. Mean BP did not correlate with platelet volume (rs = -0.100, 2P = 0.39) or platelet count (rs = 0.111, 2P = 0.34). These data suggest that platelet volume is not altered in essential hypertension.

Adult↗
PubMed1993

Double-blind comparison between nifedipine and amlodipine for the treatment of essential hypertension.

Nifedipine is an effective compound for the treatment of hypertension. However, even as a tablet formulation it is relatively short acting requiring two or three times daily administration. Amlodipine is a long-acting calcium antagonist and effectively lowers BP in patients with essential hypertension. In the present study we compared the BP-lowering effect of nifedipine and amlodipine in patients with essential hypertension. Thirteen patients were studied. They had been on nifedipine tablets for at least four weeks and DBP had been consistently > 95 mmHg. After a further month run-in on nifedipine they entered a randomised double-blind crossover study of one month' treatment with either nifedipine tablet (20 mg twice daily) or amlodipine (5 mg once daily). BP was measured 12 and 2 hours after the last dose of nifedipine and 24 and 2 hours after the last dose of amlodipine. There was a significant peak/trough effect while on nifedipine tablets, the BP being significantly higher at 12 hours than at 2 hours after the last dose (155.2/90.9 +/- 4.6/1.7 vs. 136.1/84.8 +/- 4.3/1.7 mmHg; P < 0.001/P < 0.005). There was no overall difference in BP between nifedipine and amlodipine treatment when BPs were taken at the respective troughs (i.e. 12 hours and 24 hours). If anything, amlodipine tended to be slightly more effective at least on supine SBP (155.2/90.9 +/- 4.6/1.7 vs. 147.6/89.1 +2- 4.3/1.8 mmHg; P < 0.05, NS). In conclusion, amlodipine given once daily is at least as effective as nifedipine tablets given twice daily in patients with essential hypertension.

Adult↗
PubMed1985

Correlation between octanol solvent distribution ratio and liquid chromatographic retention for some 7- and 9-substituted 1-methyl-isoguanines.

Octanol/aqueous buffer solvent distribution ratio and liquid chromatographic retention in a primarily aqueous phase were determined and correlated to estimated substituent Hansch pi values for a series of 1-methyl-isoguanines. Substituent connectivity values (simple, valence, and bond length) were also computed and factored into the correlation equation between known in vitro activity data and these lipophilic parameters. The liquid chromatographic retention data were best correlated with measured activity accounting for 61% of the variation while distribution ratio and Hansch pi accounted for 56% or 52%, respectively, when each was considered alone. Valence connectivity accounted for 30% of the variation alone but did not add significantly to the equations when factored with the other parameters.

Binding, Competitive↗
PubMed1983

High-dose methotrexate in small cell lung cancer. Lack of efficacy in preventing CNS relapse.

Few studies have incorporated high-dose methotrexate (MTX) with leucovorin rescue in the treatment of small cell lung cancer (SCLC). Potentially therapeutic levels of MTX can be achieved in the central nervous system (CNS) by systemic administration of high doses of this drug. Utilizing a combination chemotherapy program of Adriamycin, vincristine, cyclophosphamide, and methotrexate, 31 patients were sequentially assigned to receive either low-dose MTX (40 mg/m2), or high-dose MTX (500 mg/m2) with leucovorin rescue. Radiation therapy to the primary site was also administered. At these dosage levels there were no statistically significant differences in response rate or survival between the two groups. High-dose MTX did not prevent the appearance of CNS disease; there being 2/15 and 3/15 CNS relapses in the HD MTX and LD MTX treated groups, respectively. The occurrence of CNS disease did not significantly affect overall survival as compared to patients not similarly affected.

Aged↗