PubMed Health⌕ Search

Biomedical subjects

D J Graham

Publications and source records attributed to D J Graham.

At least 55 records · Page 3Linked to original sources
PubMed1991

Aortic endothelial and smooth muscle cell co-culture: an in vitro model of the arterial wall.

Interactions between vascular endothelial (EC) and smooth muscle cells (SMC) contribute both to the normal function of the vascular wall and to the pathogenesis of lesions such as atherosclerosis and fibrointimal hyperplasia. However, study of these interactions has been hampered by the difficulty in growing these two cell types in simultaneous culture. Methods using conditioned media, shared media, and bilayer culture have been described, but none is well suited to the study of vascular cell interactions. We report a method for EC-SMC co-culture that preserves bilayer morphology, allows independent study of the cells and their matrices after intervention, remains stable over long periods in culture, and permits study of changes in cell-cell interaction with growth of the cells to confluence. This simple bilayer co-culture system simulates the in vivo situation and may enhance our understanding of EC-SMC interactions.

Animals↗
PubMed1991

Indices of drug misuse for prescription drugs.

Few studies of prescription-drug misuse have taken into account the numbers of prescriptions dispensed for specific drugs. Using data from the Drug Abuse Warning Network (DAWN) and the National Prescription Audit, we calculated indices of drug misuse for specific prescription drugs that are used mainly in outpatient settings and are either benzodiazepines, barbiturates, other sedative-hypnotics, analgesics, or CNS stimulants. In 1983-1985 the drugs associated with the highest numbers of DAWN medical examiner-reported drug-misuse deaths were codeine, diazepam, propoxyphene, phenobarbital, and secobarbital. However, the drugs with the highest indices of DAWN medical examiner-reported drug-misuse deaths/100,000 dispensed prescriptions were methamphetamine, methaqualone, amobarbital, secobarbital, and glutethimide. An index of fatality risk, calculated as 100 x DAWN medical examiner-reported drug-misuse deaths/DAWN emergency room-reported drug-misuse episodes, suggested that the risk of death from a glutethimide-associated drug-misuse episode had increased 92% from 1975-1979 to 1983-1983 and in 1983-1985 was the highest for the drugs studied. These indices might assist public health authorities attempting to design effective strategies to efficiently address the problem of prescription-drug misuse.

Cause of Death↗
PubMed1990

Bacterial expression of antibody fragments that block human rhinovirus infection of cultured cells.

Human rhinoviruses are the major causative agents of the common cold in humans and have been divided into major and minor groups based on receptor specificity. cDNAs encoding the light and heavy chains of a murine monoclonal antibody that recognizes the major group receptor were cloned, abundantly expressed in Escherichia coli, and renatured into Fab fragments that blocked virus binding and protected HeLa cell monolayers from rhinovirus infection. Elimination of the cysteines normally bridging the heavy and light chains yielded molecules indistinguishable from wild-type Fab fragments in virus binding assays. Single-chain antibodies with covalently linked light and heavy variable domains were also expressed and showed receptor binding and cell protection activities. These recombinant antibody fragments are potentially useful in preventing or treating common colds in humans.

Amino Acid Sequence↗
PubMed1990

The effects of thrombin on bovine aortic endothelial and smooth muscle cells.

Recent evidence suggests that thrombin interacts with various cell types, stimulating cellular proliferation and protein and prostanoid production. To further delineate its role in vascular healing, we have studied the effects of thrombin on proliferation and matrix production by the cells of the vessel wall. The addition of thrombin (1 unit/ml) to cultures of bovine aortic smooth muscle cells resulted in an increase in cell proliferation (p less than 0.01) and number (p less than 0.03), whereas in cultures of bovine aortic endothelial cells thrombin produced a decrease in cell proliferation (p less than 0.01) and number (p less than 0.02). Thrombin also altered matrix composition in cultures of these cells. In both bovine aortic endothelial cells and bovine aortic smooth muscle cell cultures grown in the presence of thrombin, total protein content was significantly increased when compared to controls (p less than 0.03). In bovine aortic endothelial cell cultures the addition of thrombin resulted in a decrease in collagen content (p less than 0.01) and an increase in sulfated glycosaminoglycan content (p less than 0.02). In contrast, in bovine aortic smooth muscle cell cultures thrombin resulted in an increase in collagen content (p less than 0.03), whereas glycosaminoglycan content was unaffected. These findings suggest that thrombin may significantly influence vascular healing and function by altering cell number and matrix composition.

Animals↗
PubMed1990

Sequence-specific interaction of Tat protein and Tat peptides with the transactivation-responsive sequence element of human immunodeficiency virus type 1 in vitro.

Bacterially expressed Tat protein of human immunodeficiency virus type 1 binds selectively to short RNA transcripts containing the viral transactivation-responsive element (TAR). Sequences sufficient for Tat interaction map to the distal portion of the TAR stem-loop. We show that critical sequences for Tat binding are located in the single-stranded "bulge," but no requirement for specific "loop" sequences could be demonstrated. TAR RNA competed for complex formation, and TAR mutants exhibited up to 10-fold reduced affinity for Tat. Synthetic peptides containing the basic region of Tat bound selectively to TAR RNA and exhibited the same sequence requirements and similar relative affinities for mutant TAR RNA as the intact protein. These results suggest that Tat contains a small RNA-binding domain capable of recognizing TAR and implicate functional relevance for direct Tat-TAR interaction in transactivation.

Amino Acid Sequence↗
PubMed1990

An outbreak of hepatitis A among cancer patients treated with interleukin-2 and lymphokine-activated killer cells.

An outbreak of hepatitis A virus (HAV) infection occurred among cancer patients treated with interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells between July and September 1986 at six different clinical centers. Among 85 patients tested serologically for recent HAV infection, 22 (39%) of 56 susceptible patients developed acute HAV infection. Only exposure to LAK cells cultured in medium containing human serum from two specific manufactured pools was associated with HAV infection. Attack rates were 85% among patients exposed to pool X, 62% in patients exposed to pool Y, and 50% in those exposed to both pools, compared with none among the 24 susceptible persons exposed to other serum pools (P less than .001). The serum used in production of LAK cell medium was obtained from multiple paid donors. Twenty persons donated plasma to both serum pools X and Y. Although none of 12 donors tested had evidence of recent HAV infection, it is likely that an asymptomatic plasma donor viremic for HAV contaminated both serum pools and the LAK cell medium made from it.

Animals↗
PubMed1990

The mauve factor of porphyria, 3-ethyl-5-hydroxy-4,5-dimethyl-delta-3-pyrroline-2-one: effects on behaviour of rats and mice.

The monopyrrole, 3-ethyl-5-hydroxy-4,5-dimethyl-delta 3-pyrroline-2-one (HPL), was given by intraperitoneal injection to rats (0.65 mmol/kg) and to mice (0.98 and 1.95 mmol/kg). Behaviour of the rats was assessed for 1.5 hr after injection by monitoring their spontaneous activity, while behaviour of the mice was examined by ethological procedures during dyadic encounters over a 5 min. period at 50-60 min. following injection. Activity of the rats, once habituated to the cage, was reduced by HPL. No other abnormalities were discernible. In mice, HPL at 1.95 mmol/kg increased the frequency of "head twitch" and evoked a smaller increase of "backward locomotion". There were no changes in overall agonistic, social or non-social behaviour in the HPL treated mice. Plasma concentrations of HPL in mice treated with the highest dose level amounted to 0.3 +/- 0.1 mmol/l, many-fold above its plasma concentrations during acute porphyric attacks in man. It thus appears that in rodents HPL has slight behavioural activity, but that it is unlikely to play any significant role in the psychiatric disturbances of acute porphyria.

Animals↗
PubMed1990

Antibodies that block rhinovirus attachment map to domain 1 of the major group receptor.

The vast majority of human rhinovirus serotypes utilize the intercellular adhesion molecule 1 (ICAM-1) as the attachment site on susceptible cells. Twelve murine monoclonal antibodies were isolated and shown by competition binding studies to recognize three distinct, nonoverlapping epitopes on the ICAM-1 receptor. Titration of three antibodies representing each of the binding sites demonstrated that they were equally effective at blocking viral attachment. By using in vitro transcription and translation systems, a series of progressive C-terminal truncations of ICAM-1 molecules was generated. Immunoprecipitation of these fragments with each of the three antibodies indicated that all three epitopes reside within the first 82 amino acids of the receptor. Attempts to demonstrate specific binding of these in vitro-synthesized receptor fragments to virions were unsuccessful. The inability to show virion binding was most likely due to a failure of the lysates to properly glycosylate the receptor molecule, since native, unglycosylated receptor molecules isolated from cell membranes were also inactive in virus binding assays.

Animals↗
PubMed1990

The metabolism of nafimidone hydrochloride in the dog, primates and man.

1. The biotransformation of nafimidone, an imidazole-substituted anticonvulsant, has been studied by characterization of urinary metabolites in dogs, cynomolgus monkeys, baboons and man. 2. The biotransformation of nafimidone in these laboratory animals and man is initially very similar, in each case proceeding by reduction to the aliphatic alcohol metabolite, nafimidone alcohol or 1-[2-hydroxy-2-(2-naphthyl)ethyl]imidazole. 3. Further transformation of this metabolite involves oxidation in the naphthyl and imidazole functions, and/or conjugation. 4. The dog differs from the higher primates in that no metabolic modification of the naphthyl group takes place, the major metabolite in the dog being the O-beta-glucuronide of nafimidone alcohol. 5. In higher primates and man two isomers involving dihydroxylation in the naphthyl ring--1-[2-hydroxy-2-(5,6- or 7,8-dihydroxydihydro-2-naphthyl)ethyl]imidazole--were tentatively identified. These species alone showed evidence of an imidazole linked N-glucuronide of nafimidone alcohol. 6. The possible occurrence of stereoselective metabolism by the introduction of a chiral centre at C-9 in nafimidone alcohol was indicated in human urine by the presence of both epimers of the O-beta-glucuronide of nafimidone alcohol in a 2:1 ratio.

Adult↗
PubMed1988

Postmarketing surveillance for neurologic adverse events reported after hepatitis B vaccination. Experience of the first three years.

In 1982, the Centers for Disease Control, the Food and Drug Administration, and the manufacturer created a surveillance system to monitor spontaneous reports of adverse events occurring after inoculation with the new plasma-derived hepatitis B vaccine (Heptavax-B, Merck Sharp and Dohme, West Point, PA). In the three years between June 1, 1982 and May 31, 1985, an estimated 850,000 persons received the vaccine. During that period, a total of 41 reports were received for one of the following neurologic adverse events: convulsions (five cases), Bell's palsy (10 cases), Guillain-Barré syndrome (nine cases), lumbar radiculopathy (five cases), brachial plexus neuropathy (three cases), optic neuritis (five cases), and transverse myelitis (four cases). Half of these occurred after the first of three required vaccine doses. There were no deaths. Calculation of the relative risks of these illnesses after hepatitis B vaccination was highly dependent on diagnostic classification of the cases, estimates of the size of the vaccinated population, background incidence of the diseases, and the length and distribution of the hypothetical at-risk interval used in the analysis. Other factors important in judging the results of the study could not be measured, including underreporting. In some analyses, Guillain-Barré syndrome was reported significantly more often than expected (p less than 0.05, Poisson probability distribution). However, no conclusive epidemiologic association could be made between any neurologic adverse event and the vaccine. Even if such an association did exist, the preventive benefits of the vaccine in persons at high risk for hepatitis B would unequivocally outweigh the risk of any neurologic adverse event.

Evaluation Studies as Topic↗
PubMed1987

Pituitary growth hormone from human cadavers: neurologic disease in ten recipients.

Creutzfeldt-Jakob disease (CJD) has been reported in three US patients previously treated with human growth hormone derived from large pools of human cadaver pituitary glands (pit-hGH). Neurologic disorders other than CJD occurred in 10 growth hormone-deficient patients treated with pit-hGH. These 10 cases could have been chance events or true syndromes; some cases may have been caused by transmissible agents contained in the pooled growth hormone product.

Adolescent↗
PubMed1986

Pharmacokinetic, haemodynamic and radionuclide studies with nicardipine in coronary artery disease.

Pharmacokinetic, haemodynamic and radionuclide studies explored the acute pharmacokinetic and pharmacodynamic actions of nicardipine in patients with coronary heart disease. Nicardipine infusion resulted in dose-related reductions in systolic and diastolic blood pressure and an increased heart rate. Pharmacodynamic activity was evident between 12 and 24 min following 5 and 10 mg i.v. nicardipine but by 3-6 min following the higher doses of 15 and 20 mg; hypotensive activity persisted for up to 2 h. Post-infusion nicardipine concentrations declined biexponentially; however the limited data precluded formal compartmental analysis. Plasma clearance ranged from 5-12 ml/min/kg, and appeared lower than previously reported volunteer data. The haemodynamic actions of nicardipine (10 mg infusion over 10 min) in 6 patients undergoing diagnostic catheterization were reductions in systolic, diastolic and mean systemic arterial pressure and systemic vascular resistance index. Heart rate and stroke volume index increased, and there was a small but statistically significant increase in pulmonary artery occluded pressure. Radionuclide parameters were measured in 20 patients with stable angina, at rest and during supine bicycle exercise, before and 3-5 min after nicardipine 10 mg intravenously. The left ventricular ejection fraction increased by 4% at rest but not during exercise. The left ventricular rest and exercise ejection and filling rates both increased with a concurrently reduced left ventricular ejection time. There was a highly significant inverse relationship between baseline exercise ejection fraction and the response to nicardipine; ejection fraction increased with low initial values but was either unchanged or fell with higher initial values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

The metabolism of nicardipine hydrochloride in healthy male volunteers.

Four human volunteers given a 30 mg oral dose of nicardipine hydrochloride containing 40 microCi of the 14C-labelled material achieved peak plasma levels of compound-related radioactivity within one hour of dosing. Parent compound comprised only a minor fraction of the circulating radioactivity indicating rapid first-pass metabolism. Plasma radioactivity declined to background levels within 96 h and was excreted both in the urine and faeces. Urinary excretion was the favoured route comprising about 60% of the dosed radioactivity. Mean total recovered radioactivity amounted to 94.8%. Both 1,4-dihydropyridine and pyridine metabolites of nicardipine hydrochloride were excreted in the urine. The major urinary metabolites, comprising some 36% of the radioactivity excreted in the 0-8 h post-dose period, were the glucuronide conjugates of +/- 2-hydroxyethyl methyl-1,4-dihydro-2,6-dimethyl-4(m-nitrophenyl)-3,5-pyridine dicarboxylate and its pyridine from 2-hydroxyethyl methyl-2,6-dimethyl-4-(m-nitrophenyl)-3,5-pyridine dicarboxylate.

Adult↗
PubMed1985

The metabolism and pharmacokinetics of nicardipine hydrochloride in man.

Studies have been carried out to investigate the disposition of nicardipine hydrochloride following intravenous and oral administration to male volunteers. Following oral administration of a radiolabelled dose, nicardipine was shown to be rapidly and extensively metabolised and to be rapidly eliminated from plasma. After intravenous infusion of nicardipine at 5 mg-1 for 3 h, plasma levels declined biexponentially, and clearance values were of the same order as hepatic blood flow. With repeated oral administration, 20 mg three times daily for 28 days, plasma levels rose over the first 3 days of administration and then declined to some extent. Possible reasons for this decline are discussed. Steady-state plasma levels and bioavailability show a nonlinear relationship with doses over the range 10-40 mg three times daily. Food consumption has been shown to reduce the bioavailability of nicardipine when the food is taken before or at the same time as nicardipine administration.

Administration, Oral↗
PubMed1984

Pharmacokinetics of nicardipine following oral and intravenous administration in man.

The pharmacokinetics of nicardipine have been studied following oral and intravenous administration in man and the effects of food on nicardipine kinetics investigated. Following intravenous administration of nicardipine as an infusion plasma levels declined in a biphasic manner and plasma clearance values were of the same order as hepatic plasma flow. Following oral administration in the starved state nicardipine was rapidly absorbed but subject to presystemic elimination. Maximal plasma concentrations were achieved typically between 20 minutes and 2 hours after administration. The oral bioavailability of nicardipine determined by reference to a co-administered intravenous radiolabelled dose was found to be non-linearly related to dose. Bioavailability ranged from 15-45% approximately over the dose range 10-40 mg. Administration of nicardipine following a meal reduced the bioavailability of nicardipine.

Administration, Oral↗