Evaluation of human serum based tumor marker control

A human serum based tumor marker control containing 13 antigen associated with tumors or cancer cell proliferation has been developed for use in quality control of various cancer diagnostic test methodologies. The menu is comprehensive including several new antigens: the Carbohydrate Antigens 125 and 19-9, Tissue Polypeptide Antigen (TPA), Beta-2-microglobulin, as well as some traditional markers; CEA, AFP and PAP. The control is bilevel; Level I representing low values and Level II showing elevated or clinically significant values, designed to control the linear range of the assays. Stability of reconstituted material is 14 days at 2-8 degrees C and 30 days at -20 degrees C. Accelerated stress testing shows that the lyophilized material is stable for 3 years when stored at 2-8 degrees C. Testing was completed using commercially available RIA and IRMA assays. The product contains no azide or other preservatives that may interfere in these immunoassays. This product is designed for use in cancer antigen testing as part of a quality assurance program. This control will effectively assist in evaluating the accuracy and precision of immunoassay methods used in cancer evaluation.

New haemocompatible polymers assessed by thrombelastography

Mimicry of the nonthrombogenic surface of the erythrocyte has been advocated as the starting point for the development of nonthrombogenic biomaterials. Phosphorylcholine forms 88% of the outer surface of the erythrocyte, and so materials containing it should be nonthrombogenic. We have evaluated the thrombogenicity of such materials and compared them with Dacron and PTFE. Three materials containing phosphorylcholine were used: a naturally occurring phospholipid (dipalmitoylphosphatidylcholine, DPPC), a polymerized phospholipid (diacetylenic phosphatidylcholine, DAPC) and a polyester polyurethane (Polyester G). The thrombogenic potential of these materials was assessed by material thrombelastography (MTEG). This technique uses human whole blood at 37 degrees C, without an air interface, and records the elasticity of the blood clot produced. Since each material is evaluated with a control surface, extraneous differences due to factors other than the test material are eliminated. Analysis, and examples of the MTEG traces are shown and discussed. The phosphorylcholine containing materials were found to have a reduced amount of clotting factor activation, but only DPPC was better than Dacron and PTFE. MTEG demonstrated the known thrombogenicity of Dacron towards platelets. A striking reduction in platelet activation was shown for the three phosphorylcholine containing materials. These three materials show only 25% of the platelet activation of PTFE. These materials warrant further investigation as potentially very useful biomaterials.

Biomembranes as models for polymer surfaces. V. Thrombelastographic studies of polymeric lipids and polyesters

Our approach to the design of haemocompatible biomaterials is based upon the concept that coating a polymer or metal surface with phosphatidylcholine polar groups (corresponding to the major phospholipid of the human erythrocyte outer cell membrane) will improve their haemocompatibility. We have examined the effect on blood coagulation of a number of substrates: those normally used in prosthetic devices such as polyethylene terephthalate (Dacron), expanded polytetrafluoroethylene, silicone and new polymers which contain the phosphatidylcholine head group (phosphorylcholine). The effect on coagulation of blood exposed to these substrates was determined by the technique of material thrombelastography, a relatively new method for the in vitro screening of biomaterial thrombogenicity. The results obtained with Dacron, polytetrafluoroethylene and silicone are compared with those obtained with a phospholipid-dipalmitoyl-phosphatidylcholine, a polymerized phospholipid-diacetylenicphosphatidylcholine, and a range of recently synthesized polyesters, each of which contains the phosphorylcholine polar head group.

The effects of calcium, temperature and phospholamban phosphorylation on the dynamics of the calcium-stimulated ATPase of canine cardiac sarcoplasmic reticulum

Highly purified sarcoplasmic reticulum (SR) has been prepared from dog hearts and has been incubated with the triplet probe erythrosinyl isothiocyanate to specifically label the Ca2+-stimulated ATPase (Ca2+-ATPase) of the SR. The rotational mobility of the Ca2+-ATPase has been studied in this erythrosin-labelled SR using time-resolved phosphorescence polarization. Qualitatively, the mobility of the cardiac Ca2+-ATPase resembles that of skeletal muscle SR Ca2+-ATPase. Addition of Ca2+ to SR affects the mobility of the Ca2+-ATPase in a way consistent with a segment of the ATPase altering its orientation relative to the plane of the membrane. Phosphorylation of phospholamban in cardiac SR by the purified catalytic subunit of cAMP-dependent protein kinase, which is known to increase the activity of the Ca2+-ATPase by deinhibition, also alters measured anisotropy. The changes observed are not compatible with dissociation of the Ca2+-ATPase from phospholamban after the latter is phosphorylated. The data are more consistent with phospholamban associating with the Ca2+-ATPase following phosphorylation, or more complex models in which only the hydrophilic domain of phospholamban binds with and dissociates from the Ca2+-ATPase.

Fourier transform infrared spectroscopic investigation of rhodopsin structure and its comparison with bacteriorhodopsin

FT-IR spectroscopy has been used to investigate the conformation of rhodopsin in bovine rod outer segment membranes, dispersed in aqueous suspension in both 2H2O and H2O. Detailed analysis of the amide I band was made, using second-derivative and deconvolution procedures. The frequency of the major amide I component is consistent with the presence of predominantly alpha-helices within the rhodopsin structure. A spectroscopic change occurs at acidic pH with the membranes in both 2H2O and H2O. The results for the membranes dispersed in H2O at pH 7 were used to estimate a value of 0.67 for w (amide II/amide I intensity ratio in H2O). This value of w gives an estimate of the unexchanged amide protons, in rhodopsin, of 51%. The extent of amide proton exchange at acidic p2H (p2H 5 and 2), in 2H2O was also determined. The conformation of rhodopsin in its unbleached and bleached states was investigated but no significant difference in the secondary structure was observed. A comparison, after second-derivative and deconvolution analysis, of the spectra of rhodopsin with that of bacteriorhodopsin shows that both proteins exhibit a similar number of amide I components. However, with bacteriorhodopsin the amide I band occurs at a higher frequency. Bacteriorhodopsin under similar conditions, in 2H2O, has 20% more unexchanged amide protons than does rhodopsin.

The bioavailability and pharmacokinetics of morphine after intravenous, oral and buccal administration in healthy volunteers

1. The absolute bioavailability of morphine from oral aqueous solution, a controlled release oral tablet (MST-Continus) and a controlled release buccal tablet has been investigated in six healthy volunteers. 2. Analysis of plasma samples for morphine and its active metabolite morphine-6-glucuronide (M6G) was by means of a differential radioimmunoassay technique. Absolute bioavailability for morphine was estimated to be 23.9% after oral solution, 22.4% after MST-Continus and 18.7% after the buccal tablet. Maximum plasma morphine concentrations were seen at 45 min (oral solution), 2.5 h (MST) and 6 h (buccal). 3. There was no difference in the amount of M6G appearing in plasma after intravenous, oral or buccal administration but the mean ratio of AUCs for M6G: morphine in plasma after intravenous morphine was 2 : 1 compared with 11 : 1 after oral and buccal morphine.

Serum CA 125 levels and surgical findings in patients undergoing secondary operations for epithelial ovarian cancer

Serum CA 125 levels and surgical findings were prospectively compared in 96 secondary laparotomies performed on patients with epithelial ovarian cancer. All patients had documentation of an elevated CA 125 level (greater than 35 U/ml) at a time when ovarian cancer was present, and thus the tumors were known to be "marker positive." Operation was performed in 45 patients who were clinically free of disease and in 51 patients in whom there was clinical evidence of disease. At the time of operation, 29 patients had normal CA 125 levels; persistent disease was documented in 18 (62%) of these. Of the patients with normal CA 125 levels at the time of operation, those with persistent disease had a significantly higher mean CA 125 level (16.9) than those with no disease detected (8.8, p = 0.001). At exploration, cancer was found in 84 patients. There was a correlation between the maximum diameter of the largest residual tumor mass and the accuracy of the CA 125 level as follows: microscopic to 1 cm disease, 55% accuracy; greater than 1 to 5 cm disease, 80% accuracy; greater than 5 cm disease, 92% accuracy (p = 0.013). There was no correlation of CA 125 accuracy with the patient's age, number of months from initial diagnosis, tumor stage, grade, or cell type, or the highest-ever level of CA 125. Of the 84 patients with tumor found at exploration, 66 had elevated CA 125 levels, yielding a sensitivity of 78.5%. There were 12 patients with no tumor found at exploration; 11 of these had normal CA 125 levels. The one patient who had an elevated CA 125 level subsequently had a recurrence; the corrected specificity is thus 100%. An elevated CA 125 level is an accurate predictor of persistent disease. Most of these patients will have gross tumor present. The accuracy of the CA 125 level in detecting disease is related to the amount of tumor present. In our population, the predictive value of an elevated CA 125 level was 100%; the predictive value of a normal CA 125 level was 38%.

Fourier transform infrared spectroscopic studies on the secondary structure of the Ca2+-ATPase of sarcoplasmic reticulum

Fourier transform infrared spectroscopy has been applied to the study of the secondary structure of the Ca2+-ATPase of sarcoplasmic reticulum. An attempt is made to quantitatively assess the various secondary structures present. Values of 45% alpha-helix, 32% beta-sheet and 23% turns were obtained. A comparison is made of these results and those obtained using other techniques such as CD and Raman spectroscopy. The various assumptions inherent in the present procedure are discussed. The effect of various ligands, e.g. Ca2+, vanadate, ATP and phosphate, upon the structure were investigated. Upon binding these ligands no marked spectral changes were observed.

Proteolytic dissection as a probe of conformational changes in the human erythrocyte glucose transport protein

Tryptic digestion has been used to investigate the conformational changes associated with substrate translocation by the human erythrocyte glucose transporter. The effects of substrates and inhibitors of transport on the rates of tryptic cleavage at the cytoplasmic surface of the membrane have confirmed previous observations that this protein can adopt at least two conformations. In the presence of phloretin or 4,6-O-ethylidene-D-glucose, the rate of cleavage is slowed. Because these inhibitors bind preferentially at the extracellular surface of the transporter, their effects must result from a conformational change rather than from steric hindrance. A conformational change must also be responsible for the effect of the physiological substrate D-glucose, which is to increase the rate of cleavage. The regions of the protein involved in the conformational changes include both of the large cytoplasmic regions that are cleaved by trypsin: these are the central hydrophilic region of the sequence (residues 213-269) and the hydrophilic C-terminal region (residues 457-492).

Differential scanning calorimetric and Fourier transform infrared spectroscopic investigations of cerebroside polymorphism

Calorimetric and Fourier transform infrared (FTIR) spectroscopic studies have been made of the polymorphism exhibited by bovine brain cerebroside-water systems, and the effect of cholesterol and dipalmitoylphosphatidylcholine (DPPC) upon this polymorphism was investigated. The conversion of the cerebroside from the thermodynamically stable to the metastable form is found to be accompanied by spectral changes, indicating a decrease in cerebroside headgroup hydration and a rearrangement of the hydrogen-bond network. The incorporation of low concentrations of cholesterol and DPPC into cerebroside bilayers broadens the thermal transitions associated with the cerebroside as a result of the disruption of cerebroside-cerebroside interactions. This disruption is evident in the spectra of cerebroside/cholesterol mixtures.

The secondary structure of apolipoproteins in human HDL3 particles after chemical modification of their tyrosine, lysine, cysteine or arginine residues. A Fourier transform infrared spectroscopy study

Fourier transform infrared spectra of apolipoprotein E-depleted human HDL3 have been obtained in H2O and 2H2O buffers. The absorption bands in the protein amide I and amide II regions (1700-1500 cm-1) were assigned to alpha-helical, disordered and beta-strand/beta-turn structures of apolipoproteins A-I and A-II (apoA-I and apoA-II), the apolipoprotein constituents of HDL3. Modification of HDL3 by tetranitromethane (TNM) treatment, acetylation, reduction plus alkylation and 1,2-cyclohexanedione treatment derivatised tyrosine, lysine, cysteine and arginine residues, respectively, and caused alteration of the secondary structure of the HDL3 apolipoproteins to different extents. Each of the chemical modifications caused changes in the frequency of bands associated with beta-strands/beta-turns, but only TNM treatment of HDL3, as judged by the second- and fourth-derivative spectra, resulted in a shift of the band assigned to the alpha-helical structure of the proteins. In agreement with other workers, only TNM treatment of HDL3 particles was found to inhibit their binding by high-affinity cell membrane receptors. It is proposed, therefore, that receptor recognition of HDL3 particles is dependent on conservation of the alpha-helix structures within apoA-I and apoA-II, and that beta-strand/beta-turn structures are not involved. This conclusion is consistent with the predominance of amphipathic alpha-helical structures in both apolipoproteins and with the relaxed specificity of the receptors which are thought to recognise both apoA-I and apoA-II.

Comparison of Healon and Viscoat in cataract extraction and intraocular lens implantation

Sixty patients were randomly assigned to Healon (20 patients) or Viscoat (40 patients) treatment during extracapsular cataract extraction and intraocular lens implantation surgery. The 40 patients in the Viscoat group were randomly subdivided into two groups. In one group (20 patients), Viscoat was irrigated/aspirated from the eye at the close of surgery, while in the second group of 20 patients, Viscoat was left in the eye. In all Healon cases, the viscoelastic substance was removed from the eye at the end of the surgical procedure. Compared with Viscoat, Healon better facilitated the surgical procedure and appeared to be a more advantageous viscoelastic preparation. Viscoat, in many cases, caused rises in intraocular pressure in the immediate postoperative period when either removed or left in the eye at the close of surgery.

Material thrombelastography: an assessment of phosphorylcholine compounds as models for biomaterials

The use of phosphorylcholine (PC) containing compounds as possible biomaterials has been evaluated by material thrombelastography (MTEG). The detailed analysis of the MTEG technique is discussed. A remarkable reduction of thrombogenicity by compounds containing the PC group is demonstrated. The results observed with a polymerised PC-lipid indicate potential use of such substances as biomaterials with minimal thrombogenicity.

Fourier transform infrared spectra of the polypeptide alamethicin and a possible structural similarity with bacteriorhodopsin

FTIR spectra of alamethicin have been obtained in KBr disk, methanol and in aqueous lipid dispersion (above and below the lipid phase transition). The solution structure of this polypeptide in methanol has been shown by recent studies (Esposito et al. (1987) Biochemistry 26, 1043-1050) using NMR spectroscopy to be predominantly alpha-helical in content. It may therefore be regarded as a model structure for the interpretation of the spectra of certain biomembrane proteins. A comparison of the spectra with that obtained with bacteriorhodopsin shows spectral similarities, e.g. the presence of a high-frequency amide I maximum at 1661-1663 cm-1 and shoulders near 1640 cm-1 and 1620 cm-1.

Osteomyelitis presenting as a swollen elbow in a patient with the acquired immune deficiency syndrome

A patient suffering from the acquired immune deficiency syndrome (AIDS), who developed swelling of the left elbow four weeks after Staphylococcus aureus septicaemia is reported. The cause was osteomyelitis of the olecranon process.

Lipid-protein interaction. The incorporation of myelin proteolipid apoprotein into phosphatidylcholine bilayers

Bovine myelin proteolipid apoprotein (PLA), obtained in high yield and purity by a novel ultrafiltration procedure, has been used to study the perturbations produced by this protein on phosphatidylcholine bilayers, using infrared spectroscopy, nuclear magnetic resonance and fluorescence polarisation. PLA interacts with phospholipids in a similar manner to other intrinsic proteins. For bilayers in the fluid state, the fatty-acyl chain static order, as measured by deuterium NMR, is slightly increased in the presence of the protein, except at very high PLA concentrations. Phosphorus NMR reveals some perturbation of the phospholipid polar group by PLA, but to a smaller degree than occurs with other intrinsic proteins. An increase in static order above tc (the onset temperature for gel-to-fluid transition) is also detected by infrared spectroscopy. Studies using steady-state polarisation of diphenylhexatriene fluorescence indicate that the microviscosity of the bilayer increases as a function of the protein mole fraction. From these data an estimation of the average number of lipids perturbed per protein monomer has been made, and a figure of 37 phospholipid molecules determined. The data are compatible with a picture of a hydrophobic polypeptide, perturbing the phospholipids close to it, but allowing rapid (greater than 10(4) s-1) exchange with all the lipid molecules in the system.

Fourier transform infrared spectroscopic studies on gastric H+/K+-ATPase

Suspensions of membrane-bound H+/K+-ATPase in both H2O and 2H2O were investigated using Fourier transform infrared (FT-IR) spectroscopy. Second-derivative techniques were used to reveal the overlapping bands in the 1800-1500 cm-1 region. Analysis of the amide I band shows that the protein component contains substantial amounts of both alpha-helical and beta-sheet structures. Addition of 10 mM KCl to a suspension in 2H2O does not significantly affect the amide I band, indicating that the E1-E2 conformational transition of the enzyme, induced by K+, does not involve a gross change in protein secondary structure. Analysis of the amide II band in the spectra of suspensions in 2H2O shows that inhibition of the enzyme with omeprazole increases the rate of 1H-2H exchange, indicating an increase in conformational flexibility. Furthermore, an additional feature at 1628 cm-1 in the spectra of the inhibited samples in 2H2O could either support a conformational change or arise from a vibrational mode of omeprazole in its enzyme-bound form. The frequency of the band due to the symmetric stretching vibrations of the methylene groups of the lipid acyl chains increases steadily with increasing temperature indicating that there is no co-operative melting process in the lipid component of the membrane over the temperature range 9-50 degrees C. For comparison, FT-IR studies on aqueous suspensions of Na+/K+-ATPase were also carried out. These show that the protein components in the Na+/K+- and H+/K+-ATPases have similar secondary structures.

A cause-specific hazard rate analysis of prognostic factors among 199 adults with acute lymphoblastic leukemia: the Memorial Hospital experience since 1969

Results of a multivariable analysis of prognostic factors are reported for 199 previously untreated adults with acute lymphoblastic leukemia (ALL). These patients have long-term follow-up, and the probability of cure is estimated at approximately 35%. The cause-specific hazard rate analysis found lower rates of achieving complete remission (CR) in patients with WBC greater than 10,000/microL, AUL (undifferentiated) morphology, and older age. Since these patients required additional time to respond, fewer of them actually achieved CR. Characteristics directly associated with a higher rate of death during induction therapy due to severe bone marrow suppression were low serum albumin concentration (less than or equal to 3.5 g/dL), age greater than 50 years, acute undifferentiated leukemia (AUL) morphology, low Karnofsky performance status, and weight loss greater than 5%. Factors associated with a higher rate of relapse were WBC greater than 20,000/microL, non-T cell ALL, age greater than 60 years, Ph' + ALL, and time to achieve CR greater than 5 weeks. These criteria were used to identify patients at high risk of relapse. In addition, the predictive value of high WBC was found to disappear by 18 months of continuous CR. Finally, the rate of death following first relapse was higher in patients with a short first remission duration, high percentage weight loss at initial diagnosis, and older age. In summary, factors associated with a higher rate of death during attempted induction (ie, low albumin, high percent weight loss, and poor performance status) had no association with the patient's ability to remain relapse-free. Conversely, factors correlating with more extensive or resistant disease (ie, high WBC, null or B cell ALL, or Ph' + ALL) showed no association with the ability to tolerate therapy. Thus, a less toxic but more effective induction regimen is needed for patients with a poor clinical status, whereas a more intensive form of therapy appears warranted for patients presenting with more extensive or resistant disease.