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Biomedical subjects

W H Anderson

Publications and source records attributed to W H Anderson.

At least 91 records · Page 5Linked to original sources
PubMed1981

Effects of heparin on platelet aggregation and release and thromboxane A2 production.

Heparin, when added to citrated platelet-rich plasma (PRP), caused potentiation of platelet aggregation and the release reaction induced by the aggregating agents adenosine diphosphate (ADP), arachidonic acid, collagen, and epinephrine. At low concentrations (4.7 x 10(-5) M) arachidonic acid failed to cause aggregation of platelets in citrated PRP. However, in the presence of heparin, the same concentration of arachidonic acid caused aggregation. Examination of PRP for the presence of thromboxane A2 (TxA2) by use of a bioassay revealed that heparin also stimulated release of TxA2. This finding indicated that platelets released more TxA2 when they were challenged by low concentrations of arachidonic acid in the presence of heparin than in its absence. Platelets were labeled with 3H-arachidonic acid and 14C-serotonin, and attempts were made to determine whether heparin stimulated the platelet release reaction first with subsequent increased production of TxA2, or alternatively, whether heparin stimulated TxA2 production first with subsequent enhancement of the release reaction. In view of the demonstrated simultaneous release of 14C-serotonin and 3H-arachidonic acid metabolites, it appeared that either release of 14C and 3H occurs concurrently or, even if one of these events is dependent on the other, both events take place in rapid succession. Timed sequential studies revealed that in the presence of arachidonic acid, the addition of heparin hastened the apparently simultaneous release of both 14C and 3H.

Adenosine Diphosphate↗
PubMed1980

A pharmacokinetic evaluation of peritoneal dialysis for phenytoin intoxication.

Despite the indications of previous case reports and standard references, peritoneal dialysis did not appreciably enhance the elimination of phenytoin in our patient. In view of our observations, the effectiveness of peritoneal dialysis for phenytoin poisoning should be seriously questioned. A careful reassessment of the efficiency of peritoneal dialysis for phenytoin should be performed and should consider the possible role of phenytoin metabolites contributing to toxicity. Until well-controlled studies support the use of any dialytic procedure for phenytoin overdosage, the management of these patients must rely on general measures to minimize absorption of the drug and on supportive treatment as indicated by the patient's condition.

Child, Preschool↗
PubMed1980

The physical examination in office practice.

Physical illness may first declare itself as a disturbance in thinking, mood, or behavior. Recognition of physical disorders is enhanced by informed use of the relevant procedures of physical examination. Objections to physical examination are based on the assumptions that it is overly timeconsuming, is psychotherapeutically contraindicated, or requires unusual skill, but observation and minimally intrusive procedures can provide much information that may exclude emergent organic conditions. Different patients, illnesses, and settings require different levels of examination; the author describes the appropriate procedure for psychotic patients, substance abusers, patients taking psychotropic medications, and other patients.

Humans↗
PubMed1980

Strongyloidiasis in immunosuppressed hosts. Presentation as massive lower gastrointestinal bleeding.

Two cases of massive lower gastrointestinal hemorrhage in immunosuppressed patients were due to complicated infestation with Strongyloides stercoralis. The very high mortality of disseminated strongyloidiasis may in part be attributed to delays in diagnosis and treatment resulting from the complex life cycle of this nematode. Successful therapy in the cases presented consisted of reduction of corticosteroid dosage, use of thiabendazole in excess of that recommended for uncomplicated infestation, parenterally administered nutrition, multiple transfusion of blood products, and vigorous supportive management. Emphasis is given to proper categorization of patients and measures designed to prevent, detect, and treat hyperinfection in patients in whom immunosuppression is anticipated.

Adult↗
PubMed1980

Disopyramide (Norpace) distribution at autopsy of an overdose case.

A 44-year-old female died as the result of an overdose of disopyramide. An analytical method was developed and the distribution of the drug in various tissues was determined. Analysis of the blood sample indicated a drug concentration far exceeding that of the therapeutic concentration.

Adult↗
PubMed1980

Prostaglandin mediated histamine tachyphylaxis in subhuman primate tracheal smooth muscle.

The phenomenon of histamine tachyphylaxis previously observed in tracheal smooth muscle from canine species was investigated in isolated tracheal smooth muscle from subhuman primates. Tachyphylaxis to histamine was readily demonstrated by repetitive exposure to histamine. However, similar testing with acetylcholine did not indicate decreased responsiveness to this agent. The development of histamine tachyphylaxis could be prevented or reversed by inhibitors of prostaglandin synthesis (indomethacin, mefenamic acid, oxyphenbutazone). In indomethacin treated tissue, exogenous administration of prostaglandin E2 reduced the histamine response. It is concluded that the histamine tachyphylaxis which is present in subhuman primate tracheal smooth muscle is prostaglandin mediated.

Airway Resistance↗
PubMed1979

Benztropine prophylaxis of dystonic reactions.

The effectiveness of antiparkinson medication for the prevention of drug induced dystonias has remained a question. Forty patients with acute psychosis who received high potency oral antipsychotic drugs were interviewed to determine the incidence of acute dystonia. An eleven-fold increase in dystonia was found in patients who received no prophylactic medication. Such prophylaxis appears effective in preventing acute dystonia.

Adult↗
PubMed1979

Characteristics of histamine tachyphylaxis in canine tracheal smooth muscle.

In isolated canine tracheal smooth muscle, repeated administrations of histamine result in a rapid reduction in contractile response to about 15% of the initial contraction (tachyphylaxis). Development of this tachyphylaxis is specific inasmuch as: 1) it does not develop to acetylcholine (10(-6) M or 10(-4) M), or serotonin (10(-5) M; and 2) maximally developed histamine tachyphylaxis is not associated with a parallel reduction in response to acetylcholine. Pretreatment with propranolol (10(-5) M) or phentolamine (10(-4) M) does not prevent tachyphylaxis: however, pretreatment with atropine (10(-4) M) does prevent tachyphylaxis in about 50% of the animals tested. Tachyphylaxis to histamine can be reversed in a dose- and time-dependent fashion with prostaglandin synthesis inhibiting agents. The order of potency obtained with such compounds (indomethacin greater than mefenamic acid greater than oxyphenbutazone greater than acetylsalicylic acid) is consistent with potencies for inhibition of prostaglandin synthesis found in the literature. Also, in indomethacin pretreated strips in which tachyphylaxis to histamine was prevented, exogenous addition of PGE2 (1.42 x 10(1-) M to 2.84 x 10(-9) M) and PGA2 in a high concentration (2.9 x 10(-9) M) are capable of selectively reducing the response to histamine without an effect on acetylcholine-induced contractions. These data suggest that the mechanism of histamine tachyphylaxis in the canine tracheal smooth muscle preparation involves prostaglandin synthesis.

Acetylcholine↗
PubMed1979

Generation and enrichment of C4d in whole serum.

A comparison of two methods of generation of C4d (the degradation product of complement component C4) and a method for the preparation of an enriched serum fraction of this fragment are presented.

Complement Activation↗
PubMed1978

A simple method for sampling murine pulmonary and cardiac tissues for analysis of cyclic nucleotide levels.

A simple method for the rapid removal and freezing of mouse cardiac and pulmonary tissues is described. Samples thus obtained were judged to be suitable for valid estimation of in vivo levels of cyclic AMP and cyclic GMP based on the following findings: (a) the samples could be obtained and frozen in the very short time period of a few seconds; (b) no indication of adverse effects of the collection procedure was found upon examination of chemical indicators of energy metabolism; (c) the apparent rates of change of cyclic AMP and cyclic GMP levels during the first seconds after tissue isolation could produce small, but acceptable errors; and (d) dose-dependent elevations of pulmonary cAMP levels consistent with known effects in vitro were found after in vivo administration of isoproternol.

Animals↗
PubMed1977

Synthesis and function of 9,12,15-octadecatrien-6-ynoic acid in the moss ceratodon purpureus.

Biosynthesis of all-cis-9,12,15-octadecatrien-6-ynoic acid in the moss, Ceratodon purpureus, was studied using protonemata cultures with labeled 9,12,15-octadecatrienoic (linolenic) and 6,9,12,15-octadecatetraenoic acids as substrates. Both acids were efficiently converted into the acetylenic and into 5,8,11,14,17-eicosapentaenoic acids. Accordingly, the introduction of a triple bond in position 6 of linolenic acid involves formation of a double bond as a discrete step. Acetylenic acid triglycerides are reserve lipids in the moss. Under suitable growth conditions the acetylenic acids are catabolized and partly reused via acetate for de novo synthesis of fatty acids. They are not used for more direct syntheses of the common polyunsaturated fatty acids.

Fatty Acids↗
PubMed1977

Coal workers' pneumoconiosis.

Pathologic features and pathogenesis of coal workers' pneumoconiosis are reviewed. Roentenographic aspects of CWP have been examined; it is concluded that there is little or no correlation with physiologic abnormalities, and no abnormality is pathognomonic of this condition. It is suggested that coal workers who are physiologically disabled by any condition, usually heart disease or chronic obstructive pulmonary disease or both, be retired via an industry-government compensation plan. Chest roentgenograms should serve only to identify and retire those miners who have progressive massive fibrosis, and to identify those who have simple CWP; thus they may be moved to jobs in areas of the mine where dust concentrations are lower.

Chronic Disease↗