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V M Oh

Publications and source records attributed to V M Oh.

At least 19 recordsLinked to original sources
PubMed2000

Post-release drug treatment risks: strategies to minimise harm to patients.

This paper examines the perceptions and causes of drug treatment-related error, and suggests some risk reducing strategies. Interest in medical error surged recently, culminating with an estimate by the US Institute of Medicine in 1999 of 44,000 to 98,000 annual care-related deaths. Public media pressure elicited responses from health care providers, purchasers, internists and health professionals' organisations. A search was made using PubMed, focusing on papers from 1980 to date giving data on trends and causes of in-hospital drug-related error. Papers with estimates of prevalence rates of drug-induced injury in large denominator populations were selected. One hundred and seven papers on drug-related error were identified; 36 clearly defined denominators and compared rates in different groups. Occurrence rates of drug-induced harm were similar (2.2% to 6.7%) in the US and British hospital surveys. The Harvard Medical Practice Study first reliably measured the frequency of care-related patient harm. More reliable and accurate information is needed on the base-line rates of drug-related injury. Whereas there are few precise estimates of drug-induced injury, the evidence suggests that between half and two-thirds of hospital-related harmful events are preventable. Most experts agree that hospitals need to change radically their approach to professional error from one of blaming individuals to overhauling the systems for monitoring, detecting and preventing drug-related error. Hospital managers should implement voluntary, non-punitive, and confidential systems for reporting error, and apply methods of safety enhancement which succeed in high-risk industries. A realistic and achievable target could be halving of current risk. Incentives can be given to event monitoring and pharmacotherapy quality assurance, to encourage timely and accurate reporting. On-line doctors' entry of drug orders and computerised adverse event monitoring also promote error reduction.

Accidents↗
PubMed1995

Effect of extracellular potassium concentration on the sodium-potassium pump rate in human lymphocytes.

1. The purpose of this study was to determine whether physiological changes in extracellular free [K+] cause significant changes in the Na(+)-K+ pump rate and intracellular free [Na+]. 2. The Na(+)-K+ pump rate was measured in human lymphocytes by determining ouabain-sensitive 86Rb+ influx at several concentrations of K+. The Na(+)-K+ pump rate increased within the physiological range of extracellular free [K+] (K1/2 = 1.5 mmol/l). 3. To test the hypothesis that elevation of extracellular free [K+] reduces intracellular free [Na+] rapidly, which in turn then slows the pump rate during experimental incubations, lymphocyte intracellular free [Na+] was measured using the fluorochrome sodium-binding benzofuran isophthalate. With larger elevations of extracellular free [K+], intracellular free [Na+] dropped more rapidly. Thus previous discrepancies among determinations of K1/2 may be the result of variations in incubation times, which can skew the pump rates measured during incubations in various extracellular free [K+] values. Steady-state intracellular free [Na+] varied inversely with extracellular free [K+].

Adult↗
PubMed1992

Protection: risk ratio of antihypertensive drug treatment in the elderly.

In recent controlled trials using clinic-based manometry, thiazides and beta-blockers prevented cerebrovascular and coronary deaths in patients aged 60-79 years with cryptogenic hypertension (diastolic 90-119 mm Hg). Elderly patients should usually take low-dose thiazide with potassium replacement. beta-Blockers also postpone death, but may mask hypoglycaemia. Calcium blockers and low-dose angiotensin-converting enzyme (ACE) inhibitors appear preferable in diabetes, and thiazides or ACE inhibitors in heart failure or peripheral vascular disease. Maintaining average diastolic pressure at 80-84 mm Hg impairs function of the kidneys, and possibly the myocardium. Metabolic reactions worsen with age. Drug treatment should match individual daily function. By clinic manometry, the protection:risk ratio of antihypertensive treatment progressively decreases with age, reaching less than 1.0 in patients over 80-85 years. Twenty-four-hour ambulatory blood pressure information should guide treatment more reliably in patients greater than or equal to 60 years.

Aged↗
PubMed1991

Hyperinsulinaemia in thyrotoxic hypokalaemic periodic paralysis.

To test the hypothesis that there is an abnormal serum insulin response to a carbohydrate load in thyrotoxic hypokalaemic periodic paralysis (THPP), 18 men with THPP and 15 with uncomplicated thyrotoxicosis were studied during an oral glucose tolerance test. The THPP group had significantly higher fasting insulin concentrations (27.6 [3.6] vs 13.4 [1.8] mU/l; p less than 0.005) and a higher overall insulin response to oral glucose (p less than 0.001 by ANOVA) than the thyrotoxicosis group. There were no significant differences in fasting or stimulated glucose. Hyperinsulinaemia may be an important factor in the precipitation of acute paralysis in THPP.

Acute Disease↗
PubMed1991

Endothelin-1 mRNA expression in the rat kidney.

Cultured pig and bovine endothelial cells are capable of synthesizing endothelin-1 (ET-1). Thus the observation that the kidney contains a large number of binding sites for ET distributed in close proximity to endothelial cells suggests that ET-1 may be released from the endothelium to act locally on these receptors. In support of this hypothesis, using the technique of reverse transcription with specific amplification of cDNA, we report here that ET-1 mRNA is expressed in the rat kidney. The partial sequence of the amplified rat ET-1 cDNA confirms that the mature rat peptide is identical to that of the mouse, man and pig, but with some differences in codon usage.

Animals↗
PubMed1991

Influence of family history of cryptogenic hypertension, age, sex and race on lymphocyte sodium/potassium pumps.

To determine the effects of age, sex, race, and family history of hypertension on cellular cation transport, we measured specific tritiated-ouabain binding (sodium/potassium pump number), and sodium/potassium pump-mediated rubidium-86 uptake in blood lymphocytes from 105 healthy normotensive adults, comprising 23 Chinese and 19 Indian subjects who had first-degree relatives with cryptogenic hypertension, and 40 Chinese and 23 Indian matched subjects without such history. Both Chinese and Indian subjects with family history had significantly fewer sodium/potassium pumps than control subjects. Sodium/potassium pump-mediated rubidium-86 uptake was similar in these four subject groups. Seven Indian patients with untreated cryptogenic hypertension had fewer sodium/potassium pumps than normotensive Indians without family history. Age did not affect sodium/potassium pump numbers in cells from normotensive subjects. In normotensive subjects without family history. Chinese women had more sodium/potassium pumps than Chinese men, but Indian subjects did not show this pattern. We conclude that a family history of cryptogenic hypertension is associated with fewer lymphocyte sodium/potassium pumps than normal. The reduction in cellular pump number might be only a marker, or an epiphenomenon. However, the reduction in pump number might contribute to the pathogenesis of cryptogenic hypertension if it produces sodium retention in renal tubular or peripheral vascular cells.

Adult↗
PubMed1991

Multiple medication: problems of the elderly patient.

Elderly persons are apt to receive multiple drugs for many diseases. Prescribers should take extra care in persons aged over 65-70 years, and especially the very old. The main problem of the elderly is the unpredictability of their response to drugs. Self-medication with both prescribed and over-the-counter drugs worsens this problem. Drug actions may be altered by impairment of the liver, kidneys and brain, or acute illness, or both. Unwanted (adverse) drug reactions often produce rapid and unduly severe illness in the old. Some antibacterial antibiotics like the sulphonamides are best avoided. Taking many drugs together promotes adverse interactions between the drugs. Drugs with a narrow therapeutic ratio, such as warfarin, digoxin, the aminoglycosides, and many antiarrhythmic drugs, cause clinical problems. Old persons respond more abruptly to drugs like benzodiazepines, opioid analgesics, and antiparkinsonian drugs. Anaesthesia given on top of psychotropic drugs may damage the central nervous system. The elderly brain is more sensitive to induction agents and short-acting intravenous anaesthetics, like alfentanil and midazolam; the elderly liver is more easily damaged by inhalational anaesthetics like halothane. The overall benefit:risk ratio should be judged for every drug in each patient. Wherever possible, drug treatment should be avoided. If drugs are given, safe drugs with broad therapeutic ratios and tissue- or receptor-specific actions are preferable. Drug doses are usually, but not always, reduced. Benefit from a drug should be assessed early. Severe unpredictable adverse reactions need immediate cessation of the drug and prompt patient support. The practitioner should frequently review the patient's continuing need for drugs.

Aged↗
PubMed1991

Optimising drug management of individuals with cryptogenic hypertension.

Regular drug treatment in mild hypertension (diastolic blood pressure 90-104 mm Hg) reduces death from stroke, and other non-coronary vascular events. The optimum strategy remains sequential monotherapy with the lowest effective dose, with drug combinations as an option. A beta-adrenoceptor blocker or low-dose thiazide is good value treatment for many patients. beta-Blockers are good for young (under 50 years), anxious non-smoking men, men after myocardial infarction, and renal failure patients. Older persons over about 65 years, women, smokers, stroke victims, and liver disease patients should generally take a thiazide or calcium ion-channel blocker. Pregnant women and untreated gouty patients should avoid diuretics. Calcium blockers and angiotensin-converting enzyme inhibitors are preferable in severe or insulin-dependent diabetes and renal failure, and angiotensin manipulators or thiazides in heart failure or peripheral vessel disease. Hyperlipidaemia should not generally exclude thiazides or beta-blockers. Some hypertensive stroke patients without encephalopathy may not need antihypertensive drug treatment for the first 24-48 hours. Drug treatment should be tailored to individuals according to their general condition, physiological age, and any concurrent disease or medication. Unwanted drug reactions should not deter patients from fulfilling social and economic goals. The desired treatment end-point is a diastolic pressure of 85-89 mm Hg, but a compromise is usual in poorly motivated young men, and the elderly.

Humans↗
PubMed1991

Magic or medicine? Clinical pharmacological basis of placebo medication.

A placebo may be a pharmacologically active or an inert substance, a procedure, or a patient-doctor interview. Placebos work best in symptoms or disease which vary over time and between patients. The placebo works best in behaviour disorders, somatic autonomic disorders like pain, and neurohumoral disorders like hypertension. However, placebo action is incompletely defined in its molecular pharmacology. The endogenous brain systems of opioid, antiopioid, and gamma-aminobutyric acid polypeptide transmitters and neuronal receptors account in part for placebo analgesia. Non-painful stress may be mediated through other neurohumoral systems. A separate neural system might control these subsystems. Confidence based on the doctor's empathy commonly evokes the placebo effect. How the symbolic input of thought or emotion is translated into neuronal events is unknown. Double-masked 'controlled' clinical trials use placebo to reduce bias; overuse of placebo here may harm some patients. Oral placebos for routine use include thiamine at low dose. Potent drugs like glucocorticoids cannot be justified as placebo in mild disease or non-disease. Both patient and doctor are usually unaware of the placebo effect during interviews. Doctors may increase placebo efficacy by improving interpersonal skills.

Humans↗