[Extramedullary plasmocytoma of the larynx. Analysis of four cases]

Four cases of solitary extramedullary plasmocytoma of the larynx (3 men, 1 women) treated with radiotherapy are presented. Laboratory and X-ray examinations showed no evidence of systemic plasmacytoma. One patient was treated with conventional X-ray therapy and 3 patients with telegammatherapy Co-60. All patients survived 10 years with no evidence of disease.

Pharmacokinetics in organs and the intact body: model validation and reduction

Physiological pharmacokinetic models are based on the structure of the circulatory system reflecting the convective transport of drug by blood flow to the various organs and tissues. Distribution kinetics at the organ level is mostly simplified as transfer between well-stirred compartments neglecting a priori the effects of intravascular dispersion and diffusion within tissue parenchyma. Recirculatory models based on residence time theory overcome these structural limitations since they allow in a most general way the decomposition of the body into its natural subsystems. Because of the unidentifiability of the global multi-organ model on the basis of plasma concentration-time curves the following methods/experimental designs will be discussed which provide quantitative information regarding the subsystems under in vivo conditions: (i) determination of tissue concentration-time profiles (destructive sampling), (ii) estimation of the organ transit time density from input/output profiles and (iii) application of a recirculatory model with reduced complexity to clinical pharmacokinetic data.

Role of colestipol in the treatment of hyperthyroidism

The enterohepatic circulation of thyroxine (T4) and triiodothyronine (T3) is higher in thyrotoxicosis. Bile-salt sequestrants bind iodothyronines and thereby increase their fecal excretion. We, therefore, evaluated the effect of colestipol-hydrochloride administration on clinical and biochemical indices of patients with hyperthyroidism. In a prospective, controlled trial, ninety-two adult volunteers with Graves' disease, toxic autonomous nodule or toxic multinodular goiter were randomly assigned into the following treatment protocols: Group 1, 30 mg of methimazole (MMI) and 20 g of colestipol-hydrochloride (COL) daily; Group 2, 30 mg of MMI daily; and Group 3, 15 mg of MMI 20 g of COL daily. The patients were further classified into Group A, severe hyperthyroidism (baseline levels of total T3 (TT3) > or =5 nmol/l) and Group B, mild to moderate thyrotoxicosis (baseline levels of TT-3<5 nmol/l). Crook's clinical index, serum free T4 (FT4), TT3 and thyroid stimulating hormone (TSH) levels were determined before (WO), following one week (W1) and two weeks (W2) of treatment. Serum TT3 level decreased (mean+/-SE) at W1 by 40.8+/-2.6% of WO in Group1 and by 29.2+/-2.4% in Group 2 (p<0.001), and down further to 47.8+/-3.0% at W2 in Group 1, and 40.6+/-2.8% in Group 2 (p=0.01). Serum FT4 level decreased (mean+/-SE) from WO to W1 by 31.7+/-2.7% in Group 1 and by 16.2+/-3.1% in Group 2 (p=0.005), and down to 49.1+/-2.8% of WO at W2 in Group 1 and to 38.7+/-3.5% in Group 2 (p=0.07). In sub groups B COL was not effective in reducing thyroid hormone levels nor in ameliorating the clinical status of the patients. However, in Group A3 COL lowered FT4 (p=0.001) and TT3 (p=0.05) levels as compared to group A2. At W2 the clinical hyperthyroidism score improved faster in Group A1 (p<0.001) and Group A3 (p=0.012) as compared to the control Group A2. In conclusion, COL is an effective and well tolerated adjunctive agent in the treatment of hyperthyroidism. Its main effect is in severe cases of thyrotoxicosis, and in the first phase of treatment. As adjunctive COL treatment in hyperthyroidism allows reducing MMI dosage it may decrease the rate of dose dependent MMI side effects.

Role of ultrasound-guided fine-needle aspiration biopsy in evaluation of nonpalpable thyroid nodules

To determine the role of ultrasound-guided fine-needle aspiration biopsy (US-FNAB) in the evaluation of incidentally diagnosed nonpalpable thyroid nodules (NP-TN), we compared the diagnostic yield of US-FNAB in NP-TN larger than 10 mm in diameter, with palpation-guided (P-FNAB) in palpable thyroid nodules (P-TN) in the same hospital setting. Of 108 consecutive patients with NP-TN (female/male: 97/11, age: 55.2 +/- 14.3, mean +/- SD), malignancy was identified in 8 patients (7 with thyroid papillary carcinoma, 4 of which had extrathyroidal spread, and 1 patient had metastasis of pulmonary adenocarcinoma). Male gender was associated with higher prevalence of malignancy (p = 0.09) while calcification and/or cystic degeneration of the nodule did not predict the cytological findings. Malignancy was identified in 16 of 151 consecutive patients with P-TN (female/male: 139/12, age: 44.1 +/- 9.5, mean +/- SD) indicating a similar rate of malignancy in both NP-TN and P-TN. In the P-TN group thyroid cancer was more common in males (p = 0.007), and the US properties of the nodule did not predict its cytological diagnosis. In conclusion, because similar rates of cancer are detected by FNAB in both NP-TN and P-TN, an FNAB is recommended for NP-TN larger than 10 mm.

Interleukin-1 receptor antagonist and interleukin-6 for early diagnosis of neonatal sepsis 2 days before clinical manifestation

BACKGROUND

Neonatal sepsis is a common and life-threatening disorder, particularly among preterm infants. Early initiation of antibiotic therapy is frequently delayed because the first clinical signs of sepsis are non-specific and there are no reliable early laboratory indicators. We investigated the time course of expression and the prognostic power of the early inflammatory mediators interleukin-1 receptor antagonist (IL-1ra), interleukin-6 (IL-6), and circulating intercellular adhesion molecule-1 (cICAM-1) before clinical diagnosis of sepsis.

METHODS

In a prospective multicentre study, we monitored 182 very-low-birthweight infants in six intensive-care units for occurrence of sepsis. During routine or clinically indicated blood sampling, an additional sample was collected for measurement of IL-1ra, IL-6, cICAM-1, and C-reactive protein (CRP). Infants were grouped into those with proven sepsis, no infection, or unclassified. The mean study duration was 34 days. Whenever sepsis occurred, a study period of 10 days was defined: day 0 was the day of clinical diagnosis of sepsis; days -4 to -1 were the 4 days before diagnosis; days +1 to +5 were the 5 days after. We compared the concentrations of the immune mediators during the 10-day study period with group-specific baseline values from before day -4.

FINDINGS

101 infants were included in the analysis: 21 with proven sepsis, 20 with no infection, and 60 unclassified. We excluded 57 because of incomplete datasets and 24 who had early-onset sepsis. IL-1ra and IL-6 increased significantly 2 days before diagnosis of sepsis; maximum median increases within the study period were 15-fold for IL-1ra and 12-fold for IL-6. The diagnostic sensitivities of IL-1ra, IL-6, and CRP concentrations on day 0 of diagnosis were 93%, 86%, and 43%, respectively; corresponding values on day -1 were 64%, 57%, and 18%. The specificities of IL-1ra, IL-6, and CRP concentrations were 92%, 83%, and 93%. cICAM-1 had a specificity of only 64%.

INTERPRETATION

IL-1ra and IL-6 are superior to cICAM-1 and CRP as predictors of sepsis 1 or more days before clinical diagnosis. Ad-hoc measurement of these cytokines could allow earlier initiation of antibiotic therapy with corresponding improvement in outcome in very-low-birthweight infants with sepsis.

Colloidal Particles at Solid-Liquid Interfaces: Mechanisms of Desorption Kinetics

We study the sorption of colloids on equally charged surfaces. Our focus is on the time scale from hours to weeks, where adsorption is not an irreversible process but interplays with (spontaneous) desorption. Using model calculations, we show how the desorption kinetics is influenced by readsorption, a potential barrier, a secondary potential minimum, local variation of the potential, and bond aging. In the experimental part we present results of in situ observation of the sorption kinetics of polystyrene latex particles onto a glass surface. Combining the evanescent field method with video microscopy, we were able to identify the particle arrival and departure times individually and therefrom determine the adhesion time distribution function. The nonexponentiality of this function can be explained by a gamma distribution of the potential depth at the binding sites as well as by logarithmic bond aging. Copyright 1998 Academic Press.

Effect of increasing running velocity on electroencephalogram in a field test

This study was designed to measure the electroencephalogram (EEG) after exercise with increasing intensity. In a field test with increments in running velocity a 2-min EEG was recorded, together with blood lactate concentration and heart rate, after each stage. An individual protocol was used, with up to six stages of running to ensure comparability of exercise intensity among the subjects, in each of 19 athletes (17 men, 2 women) experienced in leisure-time running. The exercise consisted initially of three running stages of aerobic exercise intensity without blood lactate accumulation followed by stages with an increase of lactate concentration. The protocol of the field test led to a progressive increase in cortical activity directly after the stages without blood lactate accumulation mainly in the delta frequency band, followed by theta and alpha-1 frequency band, and less pronounced in the alpha-2 and in the beta frequency bands. After the stages with an onset and further increase of blood lactate accumulation significant decreases in the beta-2, beta-1 and alpha-1 frequency bands occurred predominantly in temporal (T3, T4, T5, and T6) and occipital (O1, and O2) electrode positions, indicating a stage-by-stage decrease of activity. This decrease may be explained by feed-back from working muscle, via afferents to the cortex from intero- and proprio-receptors and affective processes. This could suggest that through a higher running intensity indicated by an onset of blood lactate accumulation metabolic and mechanical changes led to alterations within the afferent systems influencing the level of cortical activity.

Dyskeratosis congenita: multisystemic disorder with special consideration of immunologic aspects. A review of the literature

Dyskeratosis congenita (DC) is a rare, predominantly X-linked multisystemic disorder. It demonstrates a wide spectrum of clinical manifestations and typically presents with dermatologic symptoms during the first decade of life. This review of the literature points out the importance of hematologic and immunologic alterations in defining the course and prognosis of the disease process. Pancytopenia as well as the humoral and cellular disturbances in immunologic functions associated with this disease complex may lead to severe infections that represent the main cause of death. The pathogenesis of DC is still unclear and a curative therapy is presently lacking. Recent reports suggest that a beneficial effect may be observed in the administration of hematopoietic growth factors (G-CSF, GM-CSF) for patients with DC and neutropenia.

Examining the "cost" of substance abuse in pregnancy: patient outcomes and resource utilization

OBJECTIVE

This study investigated the clinical and financial impact of self-reported maternal drug history and documented intrauterine substance exposure on maternal-neonatal morbidity and hospital costs.

STUDY DESIGN

This two-part, case-controlled, retrospective study used matching control groups.

RESULTS

Among women reporting a history of substance abuse during or prior to the index pregnancy, (a) maternal hospital costs were significantly higher and more variable; (b) birth weight, length, and gestational age were lower; (c) no significant differences were noted in the number of maternal risk factors or neonatal complications and hospital costs. In comparison of neonates with positive toxicology screens and a matched control group, there were no differences in neonatal outcomes or costs, but the number of complicating maternal risk factors and maternal hospital costs were significantly different.

CONCLUSION

Knowledge of maternal substance abuse history may be useful in planning for maternal-neonatal care needs and reimbursement for hospital care for this at-risk patient population.

Kinetic analysis of vascular marker distribution in perfused rat livers after regeneration following partial hepatectomy

BACKGROUND/AIMS

Liver clearance models are based on information (or assumptions) on solute distribution kinetics within the microvasculatory system. The aim was to study albumin distribution kinetics in regenerated livers and in livers of normal adult rats.

METHODS

A novel mathematical model was used to evaluate the distribution space and the transit time dispersion of albumin in livers following regeneration after a two-thirds hepatectomy compared to livers of normal adult rats. Outflow curves of albumin measured after bolus injection in single-pass perfused rat livers were analyzed by correcting for the influence of catheters and fitting a long-tailed function to the data.

RESULTS

The curves were well described by the proposed model. The distribution volume and the transit time dispersion of albumin observed in the partial hepatectomy group were not significantly different from livers of normal adult rats.

CONCLUSIONS

These findings suggest that the distribution space and the transit time dispersion of albumin (CV2) is relatively constant irrespective of the presence of rapid and extensive repair. This invariance of CV2 implies, as a first approximation, a similar degree of intrasinusoidal mixing. The finding that a sum of two (instead of one) inverse Gaussian densities is an appropriate empirical function to describe the outflow curve of vascular indicators has consequences for an improved prediction of hepatic solute extraction.

Determination of the minor whey protein bovine lactoferrin in cheese whey concentrates with capillary electrophoresis

In our present work we present the determination of bovine lactoferrin in whey concentrates as they are typically produced by milk and cheese industry after production of cheese. Due to the high total protein content the analysis of whey concentrate samples is difficult and even not possible by using capillary zone electrophoresis with UV detection. To enhance the detection sensitivity we applied a more promising approach by using affinity interactions in combination with laser-induced fluorescence detection. By mixing fluoresceine isothiocyanate (FITC)-conjugated polyanionic lipopolysaccharide with the mostly positively charged lactoferrin we found a significant migration time shift which is clearly dependent on the concentration of the added protein. In the second approach we developed an immunoassay using FITC-conjugated specific antibody against bovine lactoferrin. The results of the immunoassay measurements were compared with data obtained by standard enzyme-linked immunosorbent assay analysis.

Meiotic differentiation of germinal cells in three-week cultures of whole cell population from rat seminiferous tubules

The aim of the present study was to set up a culture system allowing most of the meiotic phase of rat spermatogenesis to occur in vitro. For that purpose, the differentiation of spermatogenic cells was monitored by three criteria: 1) examination of expression of genes specifically expressed at a high level in pachytene spermatocytes (the phosphoprotein p19 [p19] and the testis-specific histone TH2B) or in round spermatids (transition protein 1 [TP1] and transition protein 2 [TP2]) by reverse transcription-polymerase chain reaction (RT-PCR); 2) ploidy analysis; and 3) cytological and immunocytochemical study of the germ cells. In the first trial, we determined the changes in the ratios of p19:TP1 and TH2B:TP2 mRNA-related PCR products in the whole testis of rats between 18 and 60 days postpartum and related those results to the sequential appearance of the various types of spermatogenic cells during that period. In the second trial, our aim was to reproduce, in a culture system using seminiferous tubules from 23- to 25-day-old rats, the changes observed in vivo. The p19:TP1 and TH2B:TP2 ratios decreased dramatically in testicular extracts of rats between 32 and 40 days postpartum, i.e., at the time period during which round spermatids become more and more numerous in the testis. When seminiferous tubules were seeded in bicameral chambers, cell viability remained close to 70% of total cells throughout the 3-wk culture period. Both p19:TP1 and TH2B:TP2 ratios decreased during the first week of culture. This was attributable to a decrease in the levels of p19 and TH2B mRNAs and also to an enhancement in the relative amounts of TP1 and TP2. These changes were correlated with the appearance of a 1C cell population in the culture. Histological examination of the culture demonstrated that under the conditions of the present study, 5-bromo-2'-deoxyuridine-labeled pachytene spermatocytes of stages IV-VI were able to differentiate into secondary spermatocytes, then into round spermatids.

Development and characterization of monoclonal antibodies specific for the murine thyrotropin receptor

We have characterized 10 monoclonal antibodies (Mabs) to recombinant murine thyrotropin receptor extracellular domain (mTSHR-ecd). Affinity purified mTSHR-ecd (amino acids 22-415), expressed in a baculovirus-insect cell system, was refolded in vitro and used to hyperimmunize female Balb/c mice. Spleens were removed 10 days after a final boost of 25 microg mTSHR-ecd intraperitoneally and intravenously, and the cells were fused to SP-2 cells and cloned. Hybridoma supernatants were screened by enzyme-linked immunosorbent assay (ELISA) with folded mTSHR-ecd antigen. Ten of 18 higher affinity hybridomas were selected at random and ascites fluids prepared. Nine of the monoclonals were of IgG 1 isotype, and one was IgM. Five Mabs (M3, M4, M5, M6, and M9) inhibited the binding of 125I-TSH to functional hTSHR expressed on Chinese hamster ovary (CHO) cells, and four (M1, M3, M5, and M9) blocked the TSH-stimulated generation of cyclic adenosine monophosphate (cAMP), using the same cells. The remaining Mabs appeared to be neutral in their interaction with native TSHR. The Mabs were also compared for their reactivity to mTSHR-ecd under folding (ELISA) and unfolding (reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis [SDS-PAGE]) conditions. Most Mabs demonstrated reactivity to both conformational (folded) and linear (unfolded) forms of mTSHR-ecd, suggesting that they were generated primarily against linear epitopes although one Mab (M4) showed affinity for only folded antigen indicating a preference for a conformational epitope. Mapping the Mab epitopes using 26 overlapping peptides spanning the human (h)TSHR-ecd showed that 6 bound peptide 397-415, 1 bound peptide 352-371, and 1 peptide 22-41. These epitope mapped Mabs to the mTSHR-ecd, both receptor blocking and receptor neutral, will provide further insight into the structure-function of the TSHR ectodomain.

Adult human cardiomyocytes coexpress vimentin and Ki67 in heart transplant rejection and in dilated cardiomyopathy

BACKGROUND

The aim of this study was to investigate whether adult human cardiomyocytes may reexpress vimentin and whether this is linked to cellular activation.

METHODS

Myocardial samples of 81 heart transplant recipients (n=183) and patients with dilated cardiomyopathy (n=10) were investigated by immunohistochemistry with the use of the marker molecule vimentin, the muscle-specific protein desmin, and Ki67, a marker for cell activation.

RESULTS

Vimentin protein expression in cardiomyocytes was found in 28 samples of transplant recipients and 5 myocardial samples of patients with dilated cardiomyopathy. Coexpression of vimentin and Ki67 was found in 52 of 340 vimentin-positive cardiomyocytes.

CONCLUSIONS

We suggest that the vimentin/Ki67 coexpression indicates cell activation processes as the result of different growth stimuli.

Hepatic structure-pharmacokinetic relationships: the hepatic disposition and metabolite kinetics of a homologous series of O-acyl derivatives of salicylic acid

1. The hepatic disposition and metabolite kinetics of a homologous series of O-acyl (acetyl, propionyl, butanoyl, pentanoyl, hexanoyl and octanoyl) esters of salicylic acid (C2SA, C3SA, C4SA, C5SA, C6SA and C8SA, respectively) was determined using a single-pass, in-situ rat liver preparation. 2. The hepatic venous outflow profiles for the parent esters and the generated metabolite, salicylic acid (SA) were analysed by HPLC. Non-parametric moments analysis was used to determine the area under the curve (AUC'), mean transit time (MTT) and normalized variance (CV2) for the parent esters and generated SA. 3. Pregenerated SA ([14C]-salicylic acid) was injected into each liver with the parent ester to determine its distribution characteristics. 4. The overall recovery of ester plus metabolite was 89% of the ester dose injected and independent of the ester carbon number, suggesting that ester extraction was due to hepatic metabolism to salicylic acid. 5. The metabolite AUC' value increased directly with the lipophilicity of the parent ester (from 0.12 for C2SA to 0.95 for C8SA). By contrast, the parent AUC' decreased with the lipophilicity (from 0.85 for C2SA to zero for C8SA). The metabolite MTT value also showed a trend to increase with the lipophilicity of the parent ester (from 15.72 s for C3SA to 61.97 s for C8SA). However, the parent MTT value shows no significant change across the series. 6. The two-compartment dispersion model was used to derive the kinetic parameters for parent ester, pregenerated SA and generated SA. Consequently, these parameters were used to estimate the values of AUC', MTT and CV2 for the parent ester and metabolite. The moments values obtained using the two-compartment dispersion model show similar trends to the corresponding moments values obtained from the outflow profiles using a non-parametric approach. 7. The more lipophilic aspirin analogues are more confined to the portal circulation after oral administration than aspirin due to their more extensive hepatic elimination avoiding systemic prostacyclin inhibition. Given that aspirin's selectivity as an anti-thrombotic agent has been postulated to be due to selective anti-platelet effects in the portal circulation, the more lipophilic and highly extracted analogues are potentially more selective anti-thrombotic agents than aspirin.

[Diagnosis of sentinel lymph node in malignant melanoma: preoperative lymphoscintigraphy and intraoperative gamma probe guidance]

AIM

The sentinel lymph node (SLN) has shown to reflect the histologic features of the remainder of the lymphatic basin in patients with melanoma and is of considerable prognostic relevance. Aim of the study was to localize the SLN pre and intraoperatively by means of lymphoscintigraphy and gamma probe guidance.

METHODS

38 patients with histologically proven malignant melanoma (tumor thickness > 0.75 mm) were preoperatively examined by injecting 40 MBq 99mTc-Nanocoll intradermally around the lesion. The first lymph node identified was marked on the skin. Immediately after scintigraphy patients were referred to the operation room and intraoperatively mapped using a handheld gamma probe. Activity of the SLN and of the adjacent nodes was measured ex vivo. After excision of the SLN, the lymphatic basin was re-checked for radioactivity and activity of the SLN and of the adjacent nodes was re-measured after removal.

RESULTS

The hottest reading was found in all patients in vivo and ex vivo in the preoperatively marked lymph node. Morphologically (macroscopically, ultrasound, CT) all nodes were unsuspicious. Histologically, in 8 patients metastatic involvement of the lymph node was found which led to a wide exploration of the lymphatic basin with consecutive lymph node excision in 7 patients.

CONCLUSION

The findings suggest that combined preoperative lymphoscintigraphy and intraoperative mapping with a gamma probe is a powerful approach for exact localization of the SLN. Diagnostic detection of the SLN may have considerable impact for patient management, since extended lymph node dissection may be confined to patients presenting with positive SLN.

Relative dispersions of intra-albumin transit times across rat and elasmobranch perfused livers, and implications for intra- and inter-species scaling of hepatic clearance using microsomal data

It is recognized that vascular dispersion in the liver is a determinant of high first-pass extraction of solutes by that organ. Such dispersion is also required for translation of in-vitro microsomal activity into in-vivo predictions of hepatic extraction for any solute. We therefore investigated the relative dispersion of albumin transit times (CV2) in the livers of adult and weanling rats and in elasmobranch livers. The mean and normalized variance of the hepatic transit time distribution of albumin was estimated using parametric non-linear regression (with a correction for catheter influence) after an impulse (bolus) input of labelled albumin into a single-pass liver perfusion. The mean+/-s.e. of CV2 for albumin determined in each of the liver groups were 0.85+/-0.20 (n = 12), 1.48+/-0.33 (n = 7) and 0.90+/-0.18 (n = 4) for the livers of adult and weanling rats and elasmobranch livers, respectively. These CV2 are comparable with that reported previously for the dog and suggest that the CV2 of the liver is of a similar order of magnitude irrespective of the age and morphological development of the species. It might, therefore, be justified, in the absence of other information, to predict the hepatic clearances and availabilities of highly extracted solutes by scaling within and between species livers using hepatic elimination models such as the dispersion model with a CV2 of approximately unity.

Hepatic disposition and metabolite kinetics of a homologous series of diflunisal esters

The hepatic disposition and metabolite kinetics of a homologous series of diflunisal O-acyl esters (acetyl, butanoyl, pentanoyl, and hexanoyl) were determined using a single-pass perfused in situ rat liver preparation. The experiments were conducted using 2% BSA Krebs-Henseleit buffer (pH 7.4), and perfusions were performed at 30 mL/min in each liver. O-Acyl esters of diflunisal and pregenerated diflunisal were injected separately into the portal vein. The venous outflow samples containing the esters and metabolite diflunisal were analyzed by high performance liquid chromatography (HPLC). The normalized outflow concentration-time profiles for each parent ester and the formed metabolite, diflunisal, were analyzed using statistical moments analysis and the two-compartment dispersion model. Data (presented as mean +/- standard error for triplicate experiments) was compared using ANOVA repeated measures, significance level P < 0.05. The hepatic availability (AUC'), the fraction of the injected dose recovered in the outflowing perfusate, for O-acetyldiflunisal (C2D = 0.21 +/- 0.03) was significantly lower than the other esters (0.34-0.38). However, RN/fu, the removal efficiency number RN divided by the unbound fraction in perfusate fu, which represents the removal efficiency of unbound ester by the liver, was significantly higher for the most lipophilic ester (O-hexanoyldiflunisal, C6D = 16.50 +/- 0.22) compared to the other members of the series (9.57 to 11.17). The most lipophilic ester, C6D, had the largest permeability surface area (PS) product (94.52 +/- 38.20 mL min-1 g-1 liver) and tissue distribution value VT (35. 62 +/- 11.33 mL g-1 liver) in this series. The MTT of these O-acyl esters of diflunisal were not significantly different from one another. However, the metabolite diflunisal MTTs tended to increase with the increase in the parent ester lipophilicity (11.41 +/- 2.19 s for C2D to 38.63 +/- 9.81 s for C6D). The two-compartment dispersion model equations adequately described the outflow profiles for the parent esters and the metabolite diflunisal formed from the O-acyl esters of diflunisal in the liver.

Viscoelastic behavior of antibody films on a shear horizontal acoustic surface wave sensor

To study the viscoelastic behavior of antibody films on a surface acoustic wave device, we have measured the influence of multiple layers of antibodies onto the propagation of the wave. Attenuation and sound velocity variation caused by up to 20 layers have been measured. The results can be interpreted with the propagation of a viscously damped Love wave in a film with an extremely low velocity of sound. From our results, we conclude that, for the one- or two-layer films normally used in acoustic wave immunosensing, a pure mass effect is dominant. For thick films, a saturation of the sensor response is observed.