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J Johnson

Publications and source records attributed to J Johnson.

At least 577 records · Page 32Linked to original sources
PubMed1985

Simple procedure for removal of AMP from NADP preparation.

A simple and reliable procedure for removal of AMP from NADP preparation is described. In this procedure, a mixture of AMP and NADP solution is first incubated with 5'-nucleotidase to hydrolyze AMP to adenosine and inorganic phosphate (Pi). The reaction mixture is then applied to a Dowex 1 (formate) column. Adenosine and 5'-nucleotidase are removed by washing the column with 20 mM HCOOH. NADP is finally eluted with 3.5 M HCOOH followed by precipitation and washing with acetone. The yield of salt-free NADP is about 80%. Although Pi is coeluted with NADP in the acid form (H3PO4), it is removed during the precipitation and repeated washing with acetone. A slight modification of this procedure for simultaneous removal of AMP, ADP, and ATP from NADP preparation has also been discussed.

Adenosine Monophosphate↗
PubMed1985

Congenital ulnar deficiency. Natural history and therapeutic implications.

We have reviewed the natural history of congenital ulnar deficiency in 15 limbs in our series and in 185 limbs in the literature. The natural history suggests that there is little progression of deformity. Specific variables for prognosis have not been determined. There are no data that discuss relative ulnar length or relative forearm shortening of the involved extremity. We compared function in our 15 limbs with standards of function in the general population. Based on our findings, treatment must be individualized to maximize function and should be conservative regarding ulnar deviation of the wrist, radial head dislocation, and preservation of forearm pronation and supination. Standard reconstruction of hand anomalies is most rewarding for functional results.

Abnormalities, Multiple↗
PubMed1985

In vitro differentiation of human melanoma cells analyzed with monoclonal antibodies.

Many monoclonal antibodies (MABs) have been produced against cell surface molecules of melanoma cells, and these reagents might help in the definition of stages of differentiation of the normal and the malignant cells. In an attempt to detect MAB-defined determinants that modulate with differentiation, we treated nonpigmented human melanoma cells with the tumor promotor 12-O-tetradecanoylphorbol-13-acetate (TPA) at 16 nM. Differentiation could be induced in all 4 cell lines, as evidenced by growth retardation, development of projections, and induction of melanin or of premelanosomes in the projections as detected by transmission electron microscopy. Of the 9 MAB-defined cell surface antigens, three were shown to modulate with TPA-induced differentiation, as assessed by fluorescence microscopy and fluorescence-activated cell sorter analysis. Antigens detected by MABs 15.75 and 15.95 decreased in every one of the four cells after TPA induction of differentiation. The proteoglycan defined by 225.28S increased slightly in one, showed no change in another, and decreased in the remaining two. These three MAB-defined molecules thus are linked to differentiation and might help in designing a scheme of differentiation of the melanocyte lineage.

Antibodies, Monoclonal↗
PubMed1984

Efficacy and safety of intravenous tocainide compared with intravenous lidocaine for acute ventricular arrhythmias immediately after cardiac surgery.

In this double-blind parallel study, 99 patients with acute ventricular tachyarrhythmias after open-heart surgery were given either tocainide (50 patients) or lidocaine (49 patients) intravenously as 2 bolus injections 15 minutes apart, plus a fixed-rate infusion that started at the first bolus. If needed, a third bolus was administered and simultaneously the infusion rate was doubled. The boluses and initial infusion rate for tocainide treatment were, respectively, 250, 250 and 125 mg and 1.04 mg/min, and for lidocaine treatment, 100, 50 and 50 mg and 2.08 mg/min. When efficacy was defined as 80% or greater reduction in single ventricular premature complexes (VPCs) or complete abolition of ventricular couplets or ventricular tachycardia, no difference in efficacy between the 2 treatments was found by bedside electrocardiographic monitoring. By computer analysis of 24-hour taped electrocardiograms and a regression analysis of the proportion of patients responding favorably to treatment, it was estimated that an 80% or greater reduction of single VPCs occurred in 55% of patients during tocainide treatment and in 48% of patients during lidocaine treatment; abolition of couplets occurred in 74% and 68% of patients, respectively; and abolition of ventricular tachycardia in 87% and 73% of patients, respectively. These treatment-related differences were different (p less than 0.004). Adverse reactions occurred in 5 patients (10%) given tocainide (hypotension in 4; junctional rhythm in 1 patient; and nausea-vomiting in 1) and led to discontinuation of treatment in 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1984

Are patients with abnormal cervical smears adequately managed?

The outcome was assessed for all 1062 women in Nottingham who had a first report of abnormal cervical cytology in 1981. Satisfactory follow up could be found for only 628 (59%) of them. For 275 (26%) one subsequent normal smear had been reported but no further follow up requested. For 43 (4%), no subsequent test, after the abnormal smear, had been requested by the patient's general practitioner. Thirty patients (3%), 22 of whom had been tested at a special clinic, had not responded to a request for follow up. Even after extensive efforts we could not find the outcome in the remaining 86 (8%) of the patients. Adequate follow up of patients with abnormal cervical cytology is not being achieved. Improvements in the records systems and some changes in procedure should be made to reduce this problem.

Adult↗
PubMed1984

Effects of idazoxan on catecholamine systems in rat brain.

Experiments have been performed to assess the potency of idazoxan (RX 781094) at alpha and beta-adrenoceptors and dopamine receptors and on catecholamine uptake processes in rat brain. The effects of idazoxan on the turnover rates of noradrenaline and dopamine have been determined. Radioligand binding studies with cerebral cortex membranes have demonstrated that idazoxan exhibits 46-fold selectivity for alpha 2-adrenoceptors labelled by (3H)-idazoxan (Mean Ki +/- S.E.M. = 3.1 +/- 0.4 nM) compared with alpha 1-adrenoceptors labelled by (3H)-prazosin (Mean Ki +/- S.E.M. = 142 +/- 27 nM). Under the same conditions, yohimbine showed 6-fold selectivity for alpha 2-adrenoceptors. Idazoxan had low affinity for beta-adrenoceptors labelled by (3H)-dihydroalprenolol (IC50 value greater than 10 microM), for dopamine receptors labelled by (3H)-domperidone (IC50 value greater than 20 microM), for the (3H)-noradrenaline uptake site in rat hypothalamus (IC50 = 31 microM) and for the (3H)-dopamine uptake site in rat striatum (IC50 value approximately 800 microM). In rats treated with alpha-methyl-p-tyrosine, idazoxan (10-80 mg/kg, po) produced a marked increase (63% at 10, 217% at 20 mg/kg, po) in the apparent rate of turnover of noradrenaline in rat cortex/striatum, without affecting the rate of turnover of dopamine. This was in contrast to yohimbine (5-20 mg/kg, po) which increased the turnover rates of both catecholamines. In the absence of alpha-methyl-p-tyrosine, idazoxan (5-40 mg/kg, po) produced a dose related increase in the MHPG concentration and a small (20-30%) reduction in the steady state concentration of NA; the duration of the reduction was dose-related. DA steady state concentrations were unaffected. Idazoxan is a new selective alpha 2-adrenoceptor antagonist which should prove a valuable investigative tool in neurochemical studies and which may be a useful clinical agent in the management of the affective disorders.

Adrenergic alpha-Antagonists↗
PubMed1984

Wound care.

Explore the source record for details and available documents.

Humans↗
PubMed1984

The effect of vaginal prostaglandin E2 pessaries on induction of labor.

In a prospective randomized study, patients with a valid obstetric indication for induction of labor received either 3 mg prostaglandin E2 vaginal pessaries immediately prior to oxytocin (prostaglandin group, n = 99), or oxytocin alone (oxytocin group, n = 103). At the conclusion of the second day of induction, a significant reduction was noted in the incidence of failed induction in the prostaglandin group (4%) as compared to the oxytocin group (13%) (p less than 0.05). Twenty percent of patients in the prostaglandin group experienced successful induction with prostaglandin pessaries only. When oxytocin was required in the prostaglandin group, the maximal concentration of oxytocin infused and the duration at this concentration were significantly less than in the oxytocin group. No perinatal complications were attributed to the use of prostaglandin. Three minor maternal complications that were attributed to vaginal prostaglandin E2 did not require treatment. Our conclusion is that patients who require an induction of labor, when artificial rupture of the membranes is not feasible, benefit from the use of prostaglandin pessaries before the administration of oxytocin.

Cesarean Section↗
PubMed1984

Comparative effects of propranolol and prazosin upon serum lipids in thiazide- treated hypertensive patients.

Earlier reported thiazide-induced changes in serum lipid concentrations were confirmed with increased triglyceride and total cholesterol levels. However, lipoprotein cholesterol ratios were unchanged. Propranolol caused further increases in triglyceride and very low-density lipoprotein cholesterol, and lowered high-density lipoprotein cholesterol and the high-density lipoprotein:total cholesterol ratio. With the addition of prazosin to the polythiazide regimen, there was a significant increase in serum high-density lipoprotein cholesterol when compared with the placebo.

Adult↗
PubMed1984

Intra-articular corticosteroid- and exercise-induced arthropathy in a horse.

Methylprednisolone acetate was injected repeatedly into both intercarpal joints of a horse that had a 3rd carpal bone fracture in 1 limb. Synovial fluid from intercarpal and radiocarpal joints of both limbs were obtained serially for study. Arthropathy developed in the fractured joint following prolonged corticosteroid therapy and exercise. In the corticosteroid-injected normal joint, the hyaluronic acid concentration initially decreased, then increased. A depletion in cartilage matrix was seen at necropsy, 175 days after onset of treatment. Determination of total protein content in synovial fluid gave the earliest indication of impending arthropathy, but viscosity studies in association with determination of hyaluronic acid concentration gave a definitive assessment of joint integrity.

Animals↗