bluuebunny/crossref_metadata_2025 huggingface dataset:
Severity of depression and benzodiazepine comedication in relationship to efficacy of antidepressants in acute trials. A meta‐analysis of moclobemide trials
Authors: Angst Jules
Published: December 2004

The severity of depression at baseline, measured by the 17‐item Hamilton rating scale for depression (HAM‐D), was analysed as a predictor of the response to treatment, with response being defined as a 50 per cent improvement on the HAM‐D or a good/very good outcome on the clinical global assessment over four weeks treatment. There is a good correlation between the two outcome measures (r = 0.67), but the question of the optimal outcome measure in very mild depression remains unsolved.

The meta‐analysis was based on 2684 patients from a data pool of double‐blind trials carried out with moclobemide compared to placebo and/or standard antidepressants. The placebo response rate was high (40 per cent) in very mild depression (HAM‐D < 16) and low (12 per cent) in moderate and severe depression. The reverse was true for moclobemide and imipramine. They showed a relatively lower response rate in cases of very mild depression but an equally good response in mild, moderate and severe depression.

Co‐medication with benzodiazepines increases the response to placebo treatment and decreases the power of a comparative trial considerably. Benzodiazepines were more frequently given to patients who had been pretreated with an antidepressant before entering an experimental trial.

When analysing the outcome of antidepressant drug trials, it is recommended that investigators take into account pretreatment, co‐medication and baseline severity.
A comparison of five commonly prescribed antidepressants with particular reference to their behavioural toxicity
Authors: Sherwood Neil , Hindmarch Ian
Published: December 2004

Five antidepressant drugs (amitriptyline, dothiepin, lofepramine, fluoxetine and paroxetine) were examined for their effects on psychological function and skilled performance using a meta‐analytical technique for the combination of separate studies. Furthermore, the drugs were placed and contrasted upon dimensions of efficacy, side‐effects, safety in overdose and price in an attempt to formalize and provide a practical example of the considerations which should underlie the selection and use of such compounds. In both these analyses the profile of lofepramine, fluoxetine and paroxetine were found to be favourable compared to those of amitriptyline and dothiepin, suggesting that the prescription of older tricyclic compounds should be the exception rather than the rule in the pharmacotherapy of depression.
Use and awareness of effects of anabolic steroids and psychoactive substances among a cohort of nigerian professional sports men and women
Authors: Ohaeri Jude U. , Ikpeme Emmanuel , Ikwuagwu Princewill U. , Zamani Andrew , Odejide Olabisi A.
Published: December 2004

In 1992, 250 professional sports people (72 per cent mean, males age 25 years), mostly among those invited for screening for the Olympics, completed a questionnaire, aimed at highlighting the prevalence of use of anabolic steroids and other psychoactive substances, and the factors associated with the use of drugs.

The prevalence of life‐time use of drugs was as follows: 1.2 per cent for anabolic steroids, 0.8 per cent for amphetamines, 0.4 per cent for cocaine, 0.8 per cent for cannabis and 5.6 per cent for codeine. On the four‐item CAGE for screening for alcoholism, 3.6 per cent scored 1, while 1.2 per cent scored 2 and above. Those on steroids denied regular use of the drug, while one of them admitted having experienced DSM‐IIIR symptoms of dependence while on steroids.

Compared with estimated rates in general population samples in Nigeria, drug‐use rate among our cohort is mostly lower, but not significantly different from what obtains in general society.

Our cohort seemed largely ignorant of the deleterious effects of the use of anabolic steroids, they are liable to peer group pressure to use drugs, and seemed exposed to the temptation of being asked to be drug couriers. A programme of drug education for sports people is needed to address these issues, and keep the prevalence of drug‐use low.
Hair loss with antidepressants
Authors: Wheatley David
Published: December 2004

A 68‐year‐old woman complained of hair loss whilst taking fluoxetine which ceased when the drug was discontinued. This prompted a review of similar reports with other antidepressant drugs and it was found to have occurred with five representative tricyclic compounds and all four 5‐HT uptake‐inhibitors available in the UK. There were no reports of hair loss with trazodone or mianserin. Although extremely rare (0.01 per cent) hair loss has important social and psychological implications in the treatment of depression.
Metabolism of the PET ligand [11C]SCH 23390. Identification of two radiolabelled metabolites with HPLC
Authors: Swahn Carl‐Gunnar , Halldin Christer , Farde Lars , Sedvall Göran
Published: December 2004

[11C]SCH 23390 is a radioligand used for PET determination of the D1‐dopamine receptor in the living human brain. An HPLC procedure was developed for analysis of [11C]SCH 23390 and its radiolabelled metabolites in plasma after injection of the radioligand into human subjects in realtion to PET studies. After i.v. injection [11C]SCH 23390 rapidly declined from plasma, about 50 per cent of the radioligand remaining unchanged after 4 min and about 10 per cent after 40 min. The decline followed a biexponential time course. Two of the probable metabolites, the O‐sulphate and the O‐glucuronide of SCH 23390 were synthesized and characterized. Two radioactive substances in plasma co‐migrated with these reference compounds.
Precision of measures of saccadic eye movements and conventional psychomotor function tests
Authors: Mannion M. F. , Lynch G. , King D. J.
Published: December 2004

Measures of variability are rarely quoted in drug studies of psychomotor function. Five recent studies were therefore analysed to calculate the coefficients of variation for different tests of psychomotor function, both during and between study days. Saccadic eye movement analysis and critical flicker fusion threshold were found to have low coefficients of variation (ranging from 2·7 to 7·5 per cent) while visual analogue rating scales and the digit symbol substitution test were found to have much higher coefficients of variation (ranging from 7·9 to 17·6 per cent). It is suggested that measures of test variability be routinely assessed in psychomotor studies as a check on test methodology.
A trial of eltoprazine in the treatment of aggressive behaviours in two populations: Patients with epilepsy or Gilles de la Tourette's Syndrome
Authors: Moriarty J. , Schmitz B. , Trimble M. R. , De Koning P.
Published: December 2004

We describe an exploratory double‐blind placebo controlled trial of eltoprazine, a novel pharmacological agent, in the management of aggressive behaviours in two groups of patients: patients with epilepsy and patients with Gilles de la Tourette's Syndrome (GTS). The study was brought to a premature close. Two psychotic reactions were observed. This may reflect interactions at the 5HT1receptor group. Observations are made about the conduct of drug trials of the treatment of aggression in general and the specific clinical response seen in these two groups. We do not find evidence of the clinical value of eltoprazine for the management of aggression in these two groups.
The use of psychotropic medication in people with learning disability: Towards rational prescribing
Authors: Deb Shoumitro , Fraser William
Published: December 2004

Between 20 per cent to 50 per cent of institutionalized people with a learning disability receive psychotropic medication. A similar or a slightly lower proportion of those who live in the community also receive these drugs. There is a decreasing rate of use of these drugs with the increasing age. The rate of psychotropic drug use seems to have declined in the last decade among the community‐based population. The two main reasons for the use of these drugs are psychiatric illness and behaviour disorder. These drugs cause unacceptable side‐effects in a proportion of patients. Recent double‐blind studies lend some support to the efficacy of zuclopenthixol in the treatment of behaviour disorder. Some drugs have been use on an experimental basis to treat behavioural problems with equivocal results. These include lithium carbonate, carbamazepine, sodium valproate, fluoxetine, buspirone, naloxone, naltrxone, dextroamphetamine, methylphenidate, fenfluramine, propranolol, nadolol, amantadine and midazolam. Non‐durg dietary regimes, such as folic acid, vitamin B6, magnesium, and specific amino‐acid rich diets have also been applied in the treatment of behavioural problems. Guidelines have been proposed for a common‐sense rational approach to the use of psychotropic drugs in people with a learning disability.
Resistance to lithium: What alternatives exist?
Authors: Vanelle J. M. , Leigh T. H. , Lǒo H. , Priest R. G.
Published: December 2004

Lithium is highly valued for the treatment of mania and depression. Resistance may occur to one of its two main indications: firstly for the treatment of acute episodes of mania, and secondly for the prevention of relapse either of bipolar affective disorder (manic depression) or of unipolar affective disorder (recurrent depression).

For the management of manic episodes, alternative possibilities include neuroleptics, carbamazepine, electroconvulsive therapy (ECT) and sodium valproate. Neuroleptics are effective, but may precipitate depression. Carbamazepine is effective either alone or as a supplement to the lithium. ECT is an impressively powerful treatment for mania. Valproate appears to be effective but more studies are desirable.

Alternatives to lithium in the prevention of relapse of recurrent affective disorders include antidepressants, carbamazepine and ECT. For the prevention of relapses of bipolar affective disorder antidepressants have the disadvantage of increasing the frequency of manic episodes. In unipolar disorder they are a valid alternative to lithium but with some disadvantages. Carbamazepine is effective in the prophylaxis of bipolar affective disorder and should be considered especially in patients with rapid cycling or those with psychotic features.

Only open studies are available on ECT and valproate as prophylactic agents. Preliminary work has been carried out on verapamil, flupenthixol, clonazepam, methylene blue, clorgyline, clonidine, tryptophan and 5‐hydroxy tryptamine.
Controlled comparison of paroxetine and fluvoxamine in major depression
Authors: Ansseau M. , Gabriëls A. , Loyens J. , Bartholomé F. , Evrard J. L. , De Nayer A. , Linhart R. , Wirtz J. , Bruynooghe F. , Surinx K. , Clarysse H. , Marganne R. , Papart P.
Published: December 2004

A multicentre study compared the antidepressant efficacy and the tolerance of two selective serotonin reuptake inhibitors, paroxetine (20–30 mg/d) and fluvoxamine (50–200 mg/d) in two parallel groups of respectively 56 and 64 patients with major depression, as defined by DSM‐III‐R criteria. The duration of the study was six weeks, with assessments at baseline and at the end of weeks 1, 2, 4, and 6. For efficacy the Hamilton depression, the Hamilton anxiety scales and the clinical global impressions were used; adverse events were assessed by means of a non‐leading question. Results showed a similar improvement in both groups on all rating instruments. The total number of patients reporting adverse events did not significantly differ between paroxetine (52 per cent) and fluvoxamine (64 per cent); severe adverse events were however significantly less frequently reported with paroxetine than with fluvoxamine (13 per cent versus 28 per cent), and resulted less frequently in the discontinuation of treatment (5 per cent versus 17 per cent).
Increased 5HT‐induced platelet aggregation in mania: Lack of change following neuroleptic medication
Authors: Meagher Joseph , Leonard B. E.
Published: December 2004

Nineteen patients with mania were compared to a group of 15 schizophrenic patients and age, sex matched controls with respect to changes in 5HT‐induced platelet aggregation. In the manic patients aggregation rates were monitored immediately before the commencement of standard neuroleptic treatment (chlorpromazine, haloperidol), on days 4, 8, 15 and following discharge from hospital. The 5HT‐induced aggregation rate was increased in the manic patients compared with their controls and the schizophrenics and did not return to control levels at the end of the study period when the patients were apparently well. There was no correlation between the increased 5HT‐induced aggregation and the Young Manic Score. No change occurred in the aggregation rate to noradrenaline and adrenaline in either the manic or schizophrenia patients.

The results suggest that increased 5HT‐induced platelet aggregation may be a trait marker of mania.
The value of single photon emission tomography in psychopharmacology
Authors: Moriarty John
Published: December 2004

Functional neuroimaging with SPET and PET offers the opportunity to visualize brain function either in terms of blood flow and metabolism or receptor function using specific ligands. SPET is a more widely available and cheaper technology than PET. Continuously developing and being refined, this technology will help the understanding of brain function generally and of brain dysfunction in psychiatric disorders specifically. SPET may also be used to study how these measures of brain function change with pharmacological intervention. Receptor imaging allows the study of drug‐receptor interactions in vivo. As yet, the precise role and value of these techniques have not been established, but they do provide complementary tools to structural imaging and may ultimately provide prognostic information and facilitate refinement of the pharmacotherapeutic rationale underlying clinical practice.
Electrochemical behavior of metals as stimulus electrodes
Authors: Levine Sumner N.
Published: December 2004

A theory for the behavior of anodes as stimulus electrodes, particularly as pacemaker electrodes, is presented. Expressions are obtained for the minimum duration and energy of the stimulus. These expressions are applied to that for the dissolution of the anode and transport of the resulting ions in the tissue in order to obtain an estimate of the extent of penetration. Comparison with experimental data indicates good agreement.
Comparative studies of cyanoacrylate derivatives in vivo
Authors: Mori Shyunichi , Ota Kazuo , Takada Masayuki , Inou Tsunamasa
Published: December 2004

Seven surgical adhesives were prepared; n‐butyl, 2‐ethylhexyl, and isopropyl cyanoacrylate monomers and several combinations of ethyl cyanoacrylate and a plasticizer (either di‐2‐ethylhexyl phthalate or tricresyl phosphate). These were implanted as a thin film over the entire circumference of the adventitia of 48 canine carotid arteries. Vicissitude of cyanoacrylate polymers in vivo and tissue reaction to the polymers were traced for 6 months and investigated histologically. All adhesives tested in this study were insoluble in vivo and more resistant to biodegradation than methyl cyanoacrylate polymer. Tissue reaction against n‐butyl, 2‐ethylhexyl, or isopropyl cyanoacrylate was essentially the same as against ethyl cyanoacrylate in quality and was not less in degree than ethyl cyanoacrylate in spite of having longer side chains than ethyl radical.
Metallic and plastic prosthetic devices as vascular wall substitutes: Biophysical criteria and methods for evaluation
Authors: Sawyer P. N. , Srinivasan S.
Published: December 2004

Evidence is presented for the view that intravascular thrombosis proceeds via an electrochemical mechanism. It is strongly substantiated by some recent work on electrical wire thrombosis. These experiments show that thrombosis occurs on noble metal electrodes at potentials more positive than 0.3 v (NHE) but tends not to occur on electrodes more negative than this interfacial potential. Further, the same factors which prevent intravascular thrombosis are shown to prevent thrombosis on electrodes maintained at all potentials up to + 1.0v. Thus occurrence or prevention of thrombosis appears related to electrical and electrochemical properties of both blood and blood vessel wall. Methods for the determination of these properties are described and experimental results briefly presented. The studies have proved useful in establishing criteria for the selection of metal and plastic vascular substitutes. A combination of several electrochemical and biophysical criteria have been discovered which aid in the selection of nonthrombogenic vascular substitutes. Unfortunately not all metals which satisfy anti‐thrombotic electrochemical criteria are suitable. Many, including magnesium, have cellular and proteolytic destructive characteristics. Certain metals and electrically treated Teflon tubes do not suffer from this defect and have proven useful in preliminary testing.
A hydraulic figure‐of‐merit for heart valve prostheses
Authors: Viggers Robert F. , Robel Stephen B. , Sauvage Lester R.
Published: December 2004

The pressure losses in the currently available prostheses are too high. We believe an excellent way to focus designers' attention upon this fact is to rank the various designs according to their hydraulic efficiency. The proposal of this paper is for pressure drop vs. velocity data (pulsatile flow) to be taken similar to that of Figure 2, so that a pressure loss coefficient, Kv, based upon the valve lumen area can be found for each valve design; further, that this Kv be used to compare and rank the various valve designs. The fact that Kv is a dynamic loss coefficient guides designers toward its improvement, for this compares the prosthesis problem to many “solved” problems (propeller blade profiles, hydrofoil profiles, etc.) which are similar hydraulically. The confusion of the surgeon when confronted with conflicting claims regarding various prostheses would be largely eliminated by acceptance of Kv as a figure of hydraulic merit by those concerned with this aspect of biomedical engineering.
Tissue reaction in rabbit muscle exposed to metallic implants
Authors: Laing Patrick G. , Ferguson Albert B. , Hodge Edwin S.
Published: December 2004

The tissue reaction to metallic and nonmetallic implants in the back muscles of New Zealand White Rabbits is presented. These reactions are graded and correlated with the trace metal contained around such implanes. Correlations are drawn as to the acceptability of various materials for the manufacture of surgical implants.
Blood clotting problems in the artificial heart devices
Authors: Nosé Yukihiko
Published: December 2004

The clotting problem inside the artificial heart device is one of the major obstacles standing in the way of a successful long‐term implantation of the artificial heart. To date, there have been two artificial heart devices used clinically. One is the auxiliary ventricle and the other is the left heart bypass pump. The former is for permanent implantation and the other is implanted only temporarily. Several experimental results which had contributed to the successful implantation of the auxiliary ventricle are described, especially from the standpoint of avoiding the clotting inside the device. Basic experiments with the left heart bypass pump are also described. The valves are the foremost problem and the next is the junction of the two materials. It is ideal to have a smooth, seamless surface made entirely of one material. It is also necessary to have a flow pattern analysis inside the artificial heart device as well as a clotting pattern analysis. Since the pump oxygenator and heparinization are involved in the procedure, the clotting problems in the total heart experiment are usually less than in the left heart bypass experiments. Our most urgent requirement is the development of new antithrombogenic material. However, even with our present material a large part of the clotting could be avoided if the heart is carefully constructed.
Growth changes in mammalian cell cultures by plastic additives. (effect of triethyl citrate)
Authors: Rosenbluth S. A. , Guess W. L. , Autian J.
Published: December 2004

Inhibition of cultured mammalian cell growth was used to examine the biological activity of triethyl citrate, a common plasticizer for poly(vinyl chloride). Cell populations were determined by a sample extraction procedure and measurement of nucleic acid content (total purines and pyrimidines) by its absorbance at 268 mm̈. Triethyl citrate demonstrated strikingly different dose–effect characteristics from its theoretical hydrolysis products (ethanol and citric acid). The inhibitory effects of sodium citrate were reversed by calcium chloride while the action of triethyl citrate underwent little or no change under similar conditions. Triethyl citrate did not appear to produce resistant cell strains in culture but did seem to be degraded with time. Inhibitory action of triethyl citrate was shown to be independent of inoculum size within the ranges utilized in the study. The procedures described appear to have a number of advantages for the biological or toxicological evaluation of ingredients which might be added to a plastic formulation or to contaminates which might enter the plastic during manufacture of the item or device.
Strain on the framework of a mandibular free‐end saddle partial denture under load
Authors: Craig R. G. , Peyton F. A.
Published: December 2004

Strains were determined in a typical mandibular partial denture metal framework of the free‐end saddle type. The overall strain patterns were determined using a brittle lacquer coating technique and loads were applied vertically to positions on the saddles. The results from the coating study indicated the area of high strain were just anterior and posterior to the finishing lines. Strain gages were attached to positions anterior and posterior to the finishing lines and the strain was measured at these positions when the saddles were loaded either at a posterior or anterior position at intervals of 2 lb up to 20 lb. When a static load of 20 lb was applied to the posterior of the left saddle a strain of 750 μ in./in. was obtained, which for the alloy used was equivalent to a stress of 22,200 lb/in.2. The amount of strain observed was a function of the length of the saddle, the bulk of the framework, the relation of the site of the gage to the position of loading, the presence of an indirect retainer, and the position of the fulcrum for the loading conditions used.
X‐ray diffraction evidence for the presence of β(AgHg) in dental amalgam
Authors: Johnson Lewis B.
Published: December 2004

Samples of (Ag + Hg) amalgam and of dental amalgam have been prepared and stored at temperatures of 23, 37.5, and 60°C for various lengths of time up to 10 years. X‐ray diffraction and optical microscopy have been employed to determine the approximate increase in the β(AgHg) phase as a result of the γ → β transition in the AgHg system. Data are presented to show that the transition occurs in both systems but much less rapidly in dental amalgam. Increases in storage temperature increase the rate of the transition in both systems.
Evolution of enzyme activities and fibrin formation after contact of plasma with glass
Authors: Kingdon Henry S.
Published: December 2004

At least ten proteins play a role in normal blood coagulation. Nine of these are important in coagulation promoted by contact with glass, and are probably involved in coagulation triggered by other surfaces. These proteins have been established as separate entities by the existence of human mutants who lack, on an inherited basis, the ability to synthesize one of them. They have been assigned Roman numerals until their chemistry and mode of catalysis are better understood. Several of them have been substantially purified. Experiments with purified preparations indicate that they interact in pairs. Thrombin (activated factor II) converts fibrinogen (factor I) to fibrin by controlled partial proteolysis; the same mechanism probably operates in the conversion of factor IX to activated factor IX by activated factor XI, and gel filtration experiments are presented here which support this view. Similarly, partial proteolysis is probably the mechanism whereby thrombin converts factor XIII to activated factor XIII. Activated factor XIII converts fibrin from a urea‐soluble form to a urea‐insoluble form by transpeptidation between a glutamine residue on one fibrin strand and a lysine e‐amino residue on an adjacent fibrin strand. In general, when a pair of coagulation proteins interacts, one of them, the enzyme, converts the second from enzyme, which then catalyzes yet another similar reaction. The probable exceptions to this rule are factors VIII and V, which interact with phospholipid and another protein in a more complex manner.
Identification of rapid changes at plasma–solid interfaces
Authors: Vroman Leo , Adams Ann L.
Published: December 2004

Recording ellipsometers and surface film balance, breath patterns, and ferric oxide powder “staining” were used to observe adsorption of normal plasma constituents onto metal oxide, silicon oxide, and polymer surfaces. Adsorbed proteins could be identified by their ability to adsorb matter from corresponding antihuman sera. Data indicate that oxidized silicon crystal surfaces adsorbed fibrinogen out of plasmas within 2 sec; within 20 sec, these films lost their ability to attract antifibrinogen and were later partially removed if intact factor XII was present in the solution. One aminated nonheparinized polymer formed films that adsorbed large amounts of fibrinogen and some gamma globulins out of plasma in the ellipsometer, and platelets out of platelet‐rich plasma, as well as ferric oxide out of aqueous suspension. After taking up heparin, these polymer films appeared able to adsorb only small amounts of protein or oxide, and no detectable amounts of fibrinogen or platelets. On another aminated polymer, heparin seemed without effect. Interaction of metal surfaces with plasma may be complicated by oxidation.
Thermodynamics of adsorbed protein films
Authors: Levine Sumner N.
Published: December 2004

Previous investigation implicated surface charge and surface energy as factors which affect blood clotting. The present paper attempts to explore the theoretical basis for these affects. Expressions are also derived relating change and interfacial tension to the binding constants of the protein. Finally, the possibility of phase transition of the adsorbed protein is discussed and techniques for detecting such changes from adsorption measurements are presented.
The role of heparin in intrinsic blood coagulation
Authors: Pitlick Frances A. , Lundblad Roger L. , Davie Earl W.
Published: December 2004

A number of inhibitors of intrinsic blood coagulation have been examined. Particular emphasis was placed on heparin, heparin analogues, and hirudin. These inhibitors interfere primarily with two clotting factors in the intrinsic clotting scheme. These include factor IXa and thrombin. Our data suggest that factor IXa is the heparin‐and hirudin‐sensitive factor in plasma when coagulation is initiated via factors XII or XI, and that subsequent clotting factors remain in inactive forms. Studies with heparin and hirudin also clarified the role of thrombin in the interaction of factors IXa and VIII. It was concluded from these experiments that factor VIII readily interacts with factor IXa in the presence of calcium ions and phospholipid independent of thrombin.
Effects of proteins on elution of heparin from anticoagulant surfaces
Authors: Usdin Vera R. , Fourt Lyman
Published: December 2004

Exposure of heparin‐bearing anticoagulant materials to whole blood, plasma, or serum has been shown to lead to partial elution of heparin. Similar effects are obtained when graphite–benzalkonium–heparin (GBH) or poly–4–vinyl–pyridine–heparin (PVPyrH) surfaces are exposed to bovine plasma protein fractions. Loss of heparin from these anticoagulant materials appears to be dependent on the nature of the cationic surface and on the particular protein fraction used. With whole blood and plasma, and with most of the protein fractions studied, it was found that a larger fraction of the original heparin was eluted from GBH than from PVPyrH. Surfaces exposed to bovine Cohn fraction IV lost considerably more heparin than similar surfaces exposed to Cohn fractions I, II, III, or V, and fraction V removed less than the others, at the same or higher concentrations, and less from PVPyrH than from GBH.
Thrombin adsorption and possible relations to thrombus formation
Authors: Waugh David F. , Baughman D. Joe
Published: December 2004

In the circulation, adherent thrombi are most likely formed by nucleation and growth processes. The adsorption of an anchoring layer must be followed by further constituent interactions; these by crosslinking introduce cooperative effects which affect nucleation and growth rates. Adsorption of thrombin to nonpolar surfaces has been examined using a clotting time assay. Assay discrimination was determined by coefficients of variation: of the assay itself (0.6%), of reproducing diluted thrombin sources (0.37%) and of reproducing sets of dotting tubes containing fibrinogen (1.5%). Adsorptions are 0.54 mg/m2 at the solution–air interface, 0.77 mg/m2 at the solution–clean wall interface, and 0.04 mg/m2 to walls previously treated with thrombin. Average distance between thrombin molecules is 89 Å, the minimum adsorption energy is −11.7 kcal/mole and estimated thrombus adhesive strength 10kg/cm2. Thrombin can be the anchoring layer for a thrombus which contains thrombin, fibrin and platelets since all constituents interact with each other. The thrombin–fibrin intersection energy is about −7 kcal/mole. The platelet can, at least on interaction with thrombin, undergo structural changes which increase interaction. A variety of interactions and cooperative effects are possible. A problem is to develop protocols and assays which will permit specification of the anchoring layer and characteristics of subsequent interactions.
Specfific coagulation factor adsorption as related to functional groups on surfaces
Authors: Oja P. D. , Holmes G. W. , Perkins H. A. , Love J.
Published: December 2004

Factor assays of normal citrated plasma following incubation with nonleaching heparinized surfaces in high surface area–plasma volume ratios showed a marked pattern of reduction in factor IX activity, with lesser depression of II and X. No or modest effect on other factors was observed. In particular, no significant adsorption of factor XII (Hageman) by either cationic or anionic surfaces, was found. No consistent pattern of effects was seen with a group of strongly anionic surfaces, analogous to the sulfate and sulfamate groupings of the heparin molecule. However, certain members of this class showed profound effects on factor XI.
Initial events in interactions of blood with a foreign surface
Authors: Baier Robert E. , Dutton Robert C.
Published: December 2004

The nature of the events occurring immediately after exposing foreign surfaces to fresh flowing blood was assessed using a combination of MAIR infrared spectroscopy, ellipsometry, and contact angle measurements. Within the first 5 sec after contact with blood issuing from the jugular veins of lightly anesthesized dogs, germanium prisms were uniformly coated with strongly adherent proteinaceous filsm having an average optical thickness equivalent to 2 layers of stearic acid (approx. 50 Å) and having critical surface tensions of about 36 dyne/cm. A contact time of 60 sec led to a less uniform coating of average optical thickness equivalent to 5 layers of stearic acid (approx. 125 A), but with similar MAIR spectrum and wettability. The internal refelection spectra were consistent with the presence of either alpha‐helical or random‐chain configurations, but not with the extended chain beta‐structure for proteins. Films cast from purified fibrinogen on platinum foils gave similar spectra and exhibited similar wetting properties; these observations are consistent with the hypotehsis that initial adsorptive events are dominated by fibrinogen deposition. The involvement of small amounts of lipid or other protein remains a distinct possibility, however.
Biochemical engineering materials screening and monitoring
Authors: Homsy C. A. , Hodge R. , Gordon N. , Braggs E. E. , Estrella M.
Published: December 2004

This work was motivated by the need for a systematic compatibility screen for materials of interest for heart assist devices. A practical polymer screening and monitoring program for biochemical engineering materials was developed. Initial emphasis was placed on screening to measure degradation to low molecular weight, water miscible moieties over simulated in vivo exposure. Infrared spectrographic analysis of the simulated body fluid showed that the level of organic moiety corresponds to general clinical experience. Further confirmation of the technique came from evaluation of control polymers from The University of Texas Drug Research Laboratory. Correlation of results with cell culture viability in the presence of the pseudo body fluid is being carried out.
Retention of Freon in poly(n‐butyl α‐cyanoacrylate) sprayed films
Authors: Leonard Fred , Lusardi Joseph J. , Kulkarni Ramchandra K. , Wade Clarence W. R.
Published: December 2004

It has been found that when n‐butyl α‐cyanoacrylate is sprayed on a blood surface from an aerosol containing Freon as the propellant, the polymeric cyanoacrylate film which forms contains 1.4% propellant under the spray conditions used. Studies of the rate of loss of propellant from the film indicate that ⅓ of the Freon initially present in the film still remains after 90 min of exposure of the film to air. Possible implications of these results are discussed.
Reevaluation of plastic tubings currently used in medical and paramedical applications
Authors: Lawrence W. H. , Turner J. E. , Autian J.
Published: December 2004

A tissue culture test and a 7 day implantation method in rabbits were used to screen the toxic potential of 50 tubings used in one or more medical or paramedical applications. Results of the tests revealed that approximately 32% of the tubings contained one or more ingredients which, when released to cells or tissue, caused a toxic response. A similar study six years previously showed that 52% of the tubings tested had toxic potential. It is apparent that improvements have been made in the medical tubings (from point of view of safety), but steps must still be taken to reduce the potential risk to levels approaching zero.
Surgical suture materials coated with a layer of hydrophilic Hydron gel
Authors: Tollar M. , Štol M. , Kliment K.
Published: December 2004

Surgical suture materials were coated with a layer of hydrophilic Hydron gel. By tests carried out on tissue cultures, it has been verified that this layer itself improves the tolerance of the fiber by the organism. In addition, appropriate biologically active substances (e.g., antibiotics), preventing either the development or spreading of an infection along the fiber, may be incorporated into the gel layer. Neither the knotting ability nor other mechanical properties of the fiber are influenced by the gel coating. Preliminary clinical experiments showed good results.
Artificial membranes for corneal surgery
Authors: Refojo Miguel F.
Published: December 2004

The most commonly used synthetic polymers in corneal implants are reviewed from the viewpoint of their properties and tissue tolerance. Special attention is given to the properties of these materials in in regard to their application as artificial corneal epithelium and endothelium. It is postulated that an ideal artificial corneal membrane must exhibit, as closely as possible, the physical properties and the functional characteristics of the natural membrane. Of all the known artificial materials, homogeneous hydrogels seem to offer the best possibilities as membranes for corneal surgery. Three types of hydrogels were investigated. Poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(glyceryl methacrylate) (PGMA) are covalently linked tridimensional nonionic networks. The third type of hydrogel has multiple ionic crosslinks and belongs to the family of the polyelectrolyte complex hydrogels, made by reacting poly(vinylbenzyl‐trimethylammonium chloride) with sodium poly(styrenesulfonate). The acrylic hydrogels are very well tolerated by living tissues, but the polyelectrolyte complexes gave inconsistent results. Membranes of either type were made having permeability to water similar to that of the corneal layers. Most hydrogels are friable and do not hold sutures; this difficulty was solved by attaching the hydrogels are friable and do not hold sutures; this difficulty was solved by attaching the hydrogel membrane to the cornea by means of alkyl cyanoacrylate adhesives. n‐Heptyl and n‐butyl 2‐cyanoacrylate gave very good results in this application.
Invited communication. Adhesion between living tissue and plastics. I. Adhesion of epoxy and polyurethane resins to dentin and enamel
Authors: Lee Henry L.
Published: December 2004

In previous papers,3,4 we have discussed the synthesis of epoxy resins suitable for dental and orthopedic adhesives. In this paper we have outlined our research on two other critical aspects: surface preparation and test methods.
Refinement of the crystal structure of gamma phase silver amalgam
Authors: Baird H. Wallace , Muller Fredrik A.
Published: December 2004

The previous x‐ray analysis and structure refinement of the gamma phase of the silver‐mercury system was not completely correct. This study confirms the atomic positional coordinates in the cubic system and gives a more complete refinement of the thermal parameters.
Tensile strength determination of the interface between porcelain fused to gold
Authors: Kelly Mike , Asgar Kamal , O'Brien William J.
Published: December 2004

A method of testing the tensile strength of the porcelain–gold bond has been developed. Tensile strengths of the bond are improved primarily by the formation of an oxide layer on the gold before baking the porcelain and not by the degree of gross surface roughness. The oxide layer may act either as a transition ayer or it may create microsurface roughness. The gross surface roughness probably complicates the wetting action of the porcelain on the gold. Whether the actual bond is of a chemical nature, physical nature, or both, remains uncertain.
Effect of casting conditions on physical properties of some experimenal partial denture alloys
Authors: Asgar Kamal , Techow Bruce , Allan F. C. , Sutfin L. V.
Published: December 2004

Four alloys were tested which are being considered for use in making partial denture castings. The procedure was varied by using three spruing methods, two different waxes, two melt temperatures, and two different directions of filling. Statistical analysis techniques were used to determine the significance of the results. Spruing method was the most highly influencial of the variables and the flat method gave the best results. This method also is most relevant to clinical procedure. The effect of temperature, in fewer instances, was also in fluential. At a lesser level of signifiacnce direction of filling, and in one instance wax, had an effect.
Thromboresistant polymers by emulsion polymerization with anionic surfactants. I
Authors: Leonard Fred , Nielson Carl A. , Fadali A. Moniem , Gott Vincent L.
Published: December 2004

An elastomeric terpolymer of butyl acrylate, methyl methacrylate and methacrylamide was synthesized by emulsion polymerization using an anionic sufactant. The latex terpolymer particles where shown to have a negative charge and the solid terpolymer was negatively charged with respect to Ringer's solution. Caval rings prepared from the latex and properly post treated and cured remained patent after implantation in the inferior vena cava of dogs through a 2 week period, thus demonstrating significant thromboresistance.
Electrochemical studies on the adsorption of amino acids in relation to the compatibility of prosthetic materials and the human body
Authors: Matthews Dennis B.
Published: December 2004

The Lippman electrocapillary method was used to survey the adsorption behavior of 25 amino acids at the mercury‐solution interface. The amount of surface excess of adsorbed amino acid (Γ;), as evidenced by lowering of interfacial tension, was found to increase with the number of double bonds and/or additional nitrogen atoms which provide electron pairs. No influence of dipole moment on adsorption was observed. Adsorption was more extensive at potentials positive to the potential of zero charge, indicating a possible electrontransfer adsorption mechanism, i.e., a sharing π‐electrons rather than dipole interaction with the metal. These results are consistant with the enhanced adsorption of proteins at anodic potentials since the side groups extending from peptide linkages on a given protein are the R groups of various amino acids.
Screening study of adsorbents for urea removal from artifical kidney dialyzing fluid
Authors: Mehall J. R. , Koenig J. L. , Lindan O. , Sparks R. E.
Published: December 2004

A large number of activated carbons, carbon blacks, ion exchange resins, and inorganic adsorbents were screened for their capacity to remove urea from dilute neutral solution. An adsorbent capable of performing this task would be of assistance in decreasing the volume of dialyzing fluid required for hemodialysis. All activated carbons and carbon blacks had some adsorption capacity for urea. The most efficient was a carbonized poly(vinylidene chloride). The inorganic adsorbents exhibited negligible urea adsorption capacity, as did ion exchange resins in the ionic form at equilibrium with simulated dialyzing fluid. Several chemical reactions for urea were found not to procede in dilute neutral solution, even with carbon present to adsorb reaction products. Attenuated total reflectance infrared spectroscopy showed no band shifts in urea adsorbed on strong acid ion exchange resin. Measurement of the spectrum of urea adsorbed on carbon was prevented by adsorption of the incident energy by the carbon.
Polymers as bearing materials for total hip replacement: A friction and wear analysis
Authors: Amstutz Harlan C.
Published: December 2004

Certain thermoplastic polymers possess numerous desirable physical and mechanical properties important for total joint replacement. Their modulus of clasticity and density are close to the cartilage bone composite. Their elasticity would provide valuable damping for the transmission of shock forces. As a class of materials, polymers do not have the compression and tensile strength of metals, but the high strength‐to‐weight ratio of some polymers makes them especially attractive as a material for the socket half of the joint. The socket shape could be easily molded or machined and at a low cost. As a prime requisite they must have sufficient wear and creep resistance for a lifetime of cyclic loading and sliding. In addition they must be biologically tolerated, and the joint environment must not degrade or otherwise adversely affect the physical and mechanical properties of the polymer.

The purpose of this paper is to present a friction and wear analysis of ten thermoplastic polymers selected because their individual physical and mechanical properties suggested good wear and creep resistance. Polyimides with and without graphite have particular potential as a bearing material. The toxicological aspects of these materials are under study and will be the subject of a subsequent report.
Membrane resistance of semipermeable microcapsules
Authors: Jay Alfred W. L. , Sivertz Kristin S.
Published: December 2004

The electrical resistance of semipermeable nylon membranes on hemoglobin microcapsules has been measured by means of microelectrode punctures.

The thickness of the nylon membranes has been shown to be constant and independent of microcapsule diameter. The specific resistivity of the membrane has been estimated to be 5.6 × 103 ohm‐cm2.
Disassociation of conjugated proteins in the presence of porous glass
Authors: Stinson Harold R.
Published: December 2004

The disassociation of hemoglobin in saline solution in the presence of high surface area, powdered, porous glasss was determined. A porphyrin‐protein conjugate was disassociated at the porphyrin‐protein bond. No hydrolysis was observed at the peptide bond.
Enzymatic and electrochemical polymerization of fibrinogen
Authors: Stoner Glenn , Walker Louise
Published: December 2004

Anodic electrolysis of fibrinogen at platinum electrodes causes the formation of fibrin‐type structure at potentials below .08 V S.C.E.; at higher potentials denaturation occurs. Coated electron microscope grids were used as electrodes in fibrinogen solutions. When removed and dried these grids contain a protein film which acts as a sampler‐substrate for entities which are either in solution or are formed at the electrodes.
Electrosorption of amino acids peptides and proteins in relation to the compatibility of materials and the human body
Authors: Stoner Glenn E.
Published: December 2004

The adsorption behavior of several amino acids, simple peptides and the protein fibrinogin was measured at a charged mercury surface. Evidence was obtained for the significance of π‐electron containing amino acid groups in the adsorption of proteins on surfaces. Experiments on fibrinogin indicate that electrochemical polymerization of that protein may be the cause of thrombosis at anodes.
Identification of adsorbed protein films by exposure to antisera and water vapor
Authors: Vroman L. , Adams Ann L.
Published: December 2004

Drops of various antisera against human proteins were placed onto hydrophilic or hydrophobic surfaces that had adsorbed human proteins. The rinsed and dried plates were exposed to water vapor. Wherever an antiserum droplet had resided on a matching protein film, vapor scattered least light, indicating greatest wetting. The protein deposited within 5 seconds by plasma onto glass proved to be fibrinogen.
The effect of n‐butyl 2‐cyanoacrylate on liver function
Authors: Houston Stuart , Ousterhout Douglas K. , Sleeman Kenneth H. , Leonard Fred
Published: December 2004

n‐Butyl 2‐cyanoacrylate was implanted subcutaneously in dogs and eight different liver function tests were employed over a 6‐month period in order to determine the effect of the cyanoacrylate on liver function. The biochemical results indicated that all the values obtained were within the normal range of values reported for the dog. Pathological studies on all vital organs showed that the subcutaneously implanted cyanoacrylate polymer did not appear to cause harmful effects on the vital organs.
Polarization studies of surgical materials in ringer's solution
Authors: Mueller H. J. , Greener E. H.
Published: December 2004

The corrosion resistance of materials employed for surgical applications was dertermined and compared by means of potentiostatic anodic polarization techniques. In a physiological saline solution the passive breakdown potential of stainless steel materials was dependent upon the oxygen content opf the solution, and the microstructure of the material. The breakdown is passivity was found to be due to a pitting type of corrosion attack. Pure titanium remained passive within the limits employed in this investigation. Even though cast vitallium did not exhibit passivity breakdown in the form of a pitting attack, polarization behavior between the behavior for stainless stell and pure titanium was observed.