Methods of simplified saliva collection for the measurement of drugs of abuse, therapeutic drugs, and other molecules.
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Drug Monitoring↗
Biomedical subjects
W Schramm
Publications and source records attributed to W Schramm.
The inhibition of HIV-1 protease by interface peptides.
Previous studies have shown that some peptides derived from one of the terminal amino acid segments of the homodimeric HIV-1 protease show moderate inhibition of this enzyme probably by interfering with the "interface" structure formed by the four terminal segments of the dimer. Different peptides, with improved inhibitory potency, were devised by computer modelling, synthesized, and tested. Ac-TVSFNF, the short peptide with the best inhibition so far (IC50 = 80 microM) is identical with the C-terminal part of the gag-pol frame shift protein p6*. This suggests a regulatory function of p6* as a dimerization inhibitor of HIV protease in the virion. Peptides derived from the active site sequence of PR are inactive. The two terminal hexapeptides of reverse transcriptase are also inactive in the HIV-1 PR activity assay.
Amino Acid Sequence↗
[Infection risk caused by blood or blood products].
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Blood Proteins↗
Defined analyte-enzyme conjugates as signal generators in immunoassays.
We investigated the synthesis of progesterone-horseradish peroxidase (P-HRP) conjugates and products purified by affinity chromatography. The obtained preparations were characterized with an immobilized monoclonal antibody in solid-phase immunoassays. Three homogeneous P-HRP conjugates were isolated. Two preparations were identified to contain a single progesterone ligand on the enzyme molecule. A third preparation contained two progesterone ligands. We postulate that conjugation can occur at two different positions on the enzyme, and that the different microenvironment of the protein structure surrounding the ligand contributes to different binding constants of the conjugates with immunoglobulin. By comparing the effective binding constants derived from affinity chromatography and from Scatchard analysis, we have demonstrated that the divalent conjugate binds to antibody immobilized on planar surfaces only by a single attachment due to steric restriction. Dose-response curves for progesterone using the isolated P-HRP conjugates have been investigated and compared.
Animals↗
Clinical evaluation of a new epidural pressure monitor.
Comparative measuring of epidural pressure using the Spiegelberg probe 1 and ventricular fluid pressure was carried out in 15 neurosurgical intensive-care patients. Deviations in both directions were established, with a trend toward overestimating ventricular pressure in epidural pressure measuring (r = 0.77). Individual pulsations, spontaneous wave courses and therapy-induced pressure changes were reflected without delays. There were no complications observed with probe implantation periods for up to 6 days. The system has been shown to be mechanically stable and easy to implant. We believe the device to be fit for trend monitoring of intracranial pressure. As with other epidural pressure monitoring systems, false assessments of ventricular pressure may lead to wrong decisions as to required therapy.
Adult↗
The level of neuromuscular block needed to suppress diaphragmatic movement during tracheal suction in patients with raised intracranial pressure: a study with vecuronium and atracurium.
The effects of tracheobronchial suction before and after neuromuscular blockade with vecuronium (0.12 mg.kg-1; ED95 x 2; group A) and atracurium (0.4 mg.kg-1; ED95 x 2; group B) on intracranial pressure were studied in 18 neurosurgical patients with a Glasgow Coma Scale < 7. Despite adequate sedation, moderate to severe diaphragmatic movements (bucking and coughing) in response to carinal stimulation with significant increases in intracranial pressure (A: 18 SD 7 to 24 SD 8 mmHg; B: 19 SD 7 to 27 SD 5 mmHg) and subsequent decreases in cerebral perfusion pressure (group A: 69 SD 11 to 63 SD 8 mmHg; group B: 63 SD 11 to 59 SD 17 mmHg) could be observed without muscle relaxation. After a bolus dose of vecuronium or atracurium, profound neuromuscular paralysis quantified by the post-tetanic count, was observed after an onset time of 253 SD 72 s (vecuronium) and 159 SD 54 s (atracurium). Slight diaphragmatic movements could be elicited in only two patients in group A and in two patients in group B during tracheal suction; intracranial pressure (group A: 20 SD 8 to 20 SD 8 mmHg; group B: 19 SD 7 to 19 SD 7 mmHg) and cerebral perfusion pressure (group A: 65 SD 13 to 65 SD 13 mmHg; group B: 66 SD 12 to 65 SD 11 mmHg) remained unchanged. When coordinating respiratory therapy in neurosurgical intensive care patients, profound neuromuscular block, quantified by a post-tetanic count of at least 5 for vecuronium and 1 for atracurium, it is necessary to rule out any impact of diaphragmatic movement on intracranial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
[Effect of salpingectomy in hysterectomy on female sex hormones].
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Adult↗
[Prevention of thromboembolism with drugs].
Prophylaxis of thrombosis during and after surgery reduces the incidence of deep vein thrombosis and lung embolism in patients at risk. The kind of therapy applied is related to the individual risk of each patient. Antithrombotic stockings together with low-dose heparin or dextran, is recommended in low-risk patients. Alternatively intermittent pneumatic compression can be applied in these patients. In patients at high risk (hip or knee surgery) a prophylaxis regimen that has been proven efficient in this patient group must be used. Unfractionated and low-molecular-weight heparin (both also in combination with DHE), dextran and oral anticoagulants have been shown to be effective, but LMW heparin seems to be the best. Prophylaxis of thrombosis is also recommended in outpatients whose lower extremities are immobilized. The initiation of therapy, choice of medicament duration of therapy is ultimately the decision of the responsible physician, who must consider it for each individual patient.
Anticoagulants↗
Electroencephalographic burst suppression by propofol infusion in humans: hemodynamic consequences.
The hemodynamic effects of a propofol infusion adjusted to achieve and maintain a burst-suppression pattern [episodes of depressed background activity (electrical silence) more than 4 s alternating with a high-voltage slow activity], were studied in 10 patients without cardiorespiratory disease undergoing elective neurosurgical interventions. Propofol infusion was started after a bolus dose of 1 mg/kg at a rate of 20 mg.kg-1 x h-1, reduced after 30 min to 15 mg.kg-1 x h-1, and terminated after 60 min (1926 +/- 346 mg cumulative propofol dose, maximal serum concentration 9.2 +/- 2.9 micrograms/dL; mean +/- SD). Hemodynamic data and arterial blood samples were collected during a sedated, resting control period, and then every 15 min during drug infusion. Lactated Ringer's solution was infused at a rate sufficient to maintain pulmonary capillary wedge pressure at or above control levels (20-30 mL.kg-1 x h-1). Burst-suppression pattern in the electroencephalogram was achieved after 15.7 +/- 3.2 min and maintained until 10.9 +/- 2.6 min after the propofol infusion was terminated. Significant decreases (% of control, Friedman and Wilcoxon Wilcox test, P < 0.05) were found in heart rate (19%), mean arterial pressure (20%), cardiac index (23%), and left ventricular stroke work index (26%). No adverse consequences were caused by the propofol or crystalloid infusion. The results demonstrate that doses of propofol sufficient to silence the electroencephalogram are associated with venodilating and myocardial depressant properties. However, propofol can be administered with minimal hemodynamic risk in healthy patients when cardiac filling pressures are maintained by intravenous fluid administration.
Adult↗
Preventable mortality in Missouri: excess deaths from nine chronic diseases, 1979-1991.
For the period 1979-1991, 54% of the 644,045 deaths in Missouri were attributed to nine chronic diseases--cancers of the breast, uterine cervix, lung, colon/rectum; coronary heart disease; stroke; diabetes; chronic obstructive pulmonary disease; hepatic diseases/cirrhosis. Elimination of risk factors and screening have been shown to reduce the mortality caused by these diseases. To evaluate the range in excess mortality in the state, we calculated excess mortality by county and correlated these rates with three sociodemographic variables. Based on these analyses, an estimated 100,000 deaths may have been prevented through prevention and early detection activities.
Adult↗
Experience with prophylaxis in Germany.
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Adolescent↗
Cocaine and benzoylecgonine in saliva, serum, and urine.
We studied the feasibility of using saliva to detect cocaine and benzoylecgonine. Saliva was collected as an ultrafiltrate directly in the mouth with an osmotic device. We analyzed by immunoassay matched samples of urine, blood, and salivary ultrafiltrate from 69 patients who had used cocaine within 24 h of sample collection. Cocaine concentrations were 4.9 times higher in saliva than in serum; benzoylecgonine concentrations were 2.5 times higher in serum. Seven urine and two serum samples had undetectable concentrations of cocaine, but all 69 saliva samples were positive for the drug. For benzoylecgonine detection, all urine samples were positive and three serum and one saliva sample were negative. We also analyzed 43 samples of saliva by gas chromatography/mass spectrometry: all were positive for benzoylecgonine, whereas 40 were positive for cocaine. We conclude that simultaneous measurement of cocaine and benzoylecgonine in saliva is suitable in screening for recent cocaine use.
Adolescent↗
Testosterone concentration is increased in whole saliva, but not in ultrafiltrate, after toothbrushing.
The concentration of testosterone in whole saliva is significantly increased (by 9%) after toothbrushing. In ultrafiltrates of saliva collected at the same time as the whole saliva, testosterone concentrations after toothbrushing were unchanged. In 88% of the 162 whole-saliva specimens, but not in the ultrafiltrates, we also measured higher hemoglobin concentrations after toothbrushing. We conclude that the increase of testosterone in whole saliva after toothbrushing can be attributed to a protein-bound fraction. For analytes that are bound to serum proteins, salivary measurements can give spurious results. This problem can be avoided by using as a diagnostic medium an ultrafiltrate of saliva collected directly in the mouth.
Adult↗
A new immunoassay for soluble fibrin enables a more sensitive detection of the activation state of blood coagulation in vivo.
A novel sandwich immunoassay for measurement of soluble fibrin in plasma has been developed. For immunization we used the synthetic heptapeptide Gly-Pro-Arg-Val-Val-Glu-Arg representing the amino terminus of the alpha-chain of human fibrin. A monoclonal IgG1 antibody was obtained by conventional hybridoma technology. To increase convenience, the sandwich immunoassay was developed for the Enzymun-Test systems which are based on streptavidin pre-coated tubes. The new assay was designed with the same fibrin specific antibody both in biotinylated and in peroxidase-labelled form. Fibrin in native plasma samples could only be detected after pre-incubation of the plasma with chaotropic ions. Test results were calculated using a standard curve comprising six fibrin standards (0-50 micrograms/ml). Precision of the method was satisfactory; intra-assay CVs using plasma samples ranged between 5.0% (23.7 micrograms/ml) and 12.4% (0.2 microgram/ml). CVs of interassay precision measurements using standards as samples range between 7.3% (25.0 micrograms/ml) and 11.4% (1.0 micrograms/ml). The lower detection limit was 0.12 microgram/ml. Investigations of normal range in 70 age-matched healthy individuals resulted in a mean of 1.12 micrograms/ml. Linearity was excellent; recovery of high fibrin plasma after dilution with normal plasma was always between 100 and 107%. Fibrin specificity was due to the monoclonal antibody 2B5 used and no cross reactivity with fibrinogen, fibrinogen split products or fibrin D-dimer was observed. Fibrin fragment E1 (studied by Dempfle CE, et al. Blood Coag Fibrinol 1993; 4: 79-86) and fragments X and Y showed moderate cross reactivity in the assay and caused some overestimation of fibrin at high fibrin split product concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
Treatment of coumarin-induced skin necrosis with a monoclonal antibody purified protein C concentrate.
BACKGROUND AND DESIGN--Protein C is a vitamin K-dependent plasma protein that is converted to the serine protease activated protein C by the thrombin-thrombomodulin complex. Activated protein C functions as a natural anticoagulant by inactivating the cofactors of the coagulation cascade, factors Va and VIIIa. Coumarin (warfarin)-induced skin necrosis is thought to be due to a rapid elimination of protein C relative to other vitamin K-dependent factors during the initial phase of oral anticoagulation. We have used a highly purified protein C concentrate to treat a patient with acquired protein C deficiency who developed skin necrosis during the initial phase of oral anticoagulant therapy. OBSERVATIONS AND CONCLUSIONS--During protein C concentrate therapy, no further skin lesions appeared, and the healing process of necrotic areas was facilitated. Replacement therapy with protein C concentrate appears to be safe and effective as an adjunctive treatment for coumarin-induced skin necrosis.
Aged↗
Antibody-antigen complex formation with immobilized immunoglobulins.
We have investigated the complex formation between an immobilized monoclonal antibody and antigens that differ in size about 50-fold. As a model system, we used an iodinated progesterone derivative and a progesterone-horseradish peroxidase conjugate as tracer and a monoclonal antibody as binding protein. The antibody was immobilized by four different methods: physical adsorption, chemical binding, and binding via protein G in the absence or presence of a protective protein (gelatin). These investigations have shown that the performance of competitive immunoassays is determined by a combination of factors: (a) the relative size of the analyte and the tracer, (b) the antibody density on the solid matrix, (c) the method of immobilization of the antibody, and (d) the binding constants between antibody-analyte and antibody-tracer. All of these interactions have to be considered in designing an optimal immunoassay. The smaller antigen can form a 3- to 35-fold higher maximal complex density than the larger antigen. Dose-response curves are less affected by the size of the tracer than by the binding constant with the antibody. A large enzyme tracer with a relatively low binding constant can, therefore, provide a more sensitive assay. On the other hand, the increase in complex density achieved with a smaller tracer yields a higher signal that in turn can provide a better signal-to-noise ratio in highly sensitive competitive solid-phase immunoassays. We have suggested a model for antibody immobilization that accounts for the interdependence of tracer size, complex formation, and antibody density. The methods described can be used to design and optimize immunoassays of predefined performance characteristics. The results are particularly useful for converting radioimmunoassays to enzyme immunoassays.
Antibodies, Monoclonal↗
Cotinine in an ultrafiltrate of saliva.
BACKGROUND: We have developed a device for the simplified collection of a prepurified sample of saliva in the mouth. METHOD: The device is based on the principle of an osmotic pump and accumulated about 1.2 ml of an ultrafiltrate of saliva within 8 min. We have investigated the ultrafiltrate for its utility as a biological medium in the evaluation of cigarette smoking status. RESULTS: (a) In 58 matched samples from 13 subjects, the correlation coefficient for the cotinine concentration in the saliva and the ultrafiltrate was 0.95; (b) in matched plasma and ultrafiltrate samples from 27 smokers, the correlation coefficient for the cotinine concentrations was 0.96 with plasma containing 1.2 times the ultrafiltrate mean; (c) in a nonsmoker, elevated cotinine levels could be detected in the ultrafiltrate more than 24 hr after smoking 2 cigarettes, and the pattern of rise and decrease reflected that in whole saliva; and (d) in a habitual smoker; the mean cotinine concentration in the ultrafiltrate was 157 ng/ml (SD +/- 25.7 ng/ml) during a period of smoking 15 cigarettes per day and dropped to a mean of 47 ng/ml (SD +/- 10.5) when smoking was reduced to 5 cigarettes per day; after cessation of smoking, detectable concentrations of cotinine persisted for up to 5 days. CONCLUSION: The device facilitated the aesthetic, noninvasive collection of a biological sample useful in the validation of smoking status.
Adult↗
Continuous monitoring of analyte concentrations.
We have investigated the application of a modified, heterogeneous, competitive enzyme immunoassay for the continuous measurement of small analytes in a medium stream. The analytical system contains two antibodies that are immobilized on spatially separated areas, one binding the analyte (Ab1) and the other binding the enzyme (Ab2). An analyte-enzyme conjugate serves as signal generator. The analyte-enzyme conjugate functions as a heterobifunctional shuttle that can bind to either antibody. A semipermeable membrane retains the enzyme shuttle in the internal volume of the sensor but permits the passage of small analytes from the medium stream. The amount of enzyme bound to Ab1 is inversely proportional and the amount of enzyme bound to Ab2 is directly proportional to the analyte concentration. We have demonstrated that this analytical system (1) can provide a larger total signal; (2) has a sensitivity comparable with conventional competitive immunoassays; (3) does not require the separation of bound from free antigens; and (4) is therefore suitable for the continuous measurement of analytes in a medium stream. With a model system, an increase from 0 ng ml-1 to 20 ng ml-1 of the steroid hormone progesterone and the subsequent fall to 0 ng ml-1 could be monitored.
Antibodies, Monoclonal↗