Kosten der Unterkieferfrakturversorgung: Eine prospektive Untersuchung

PURPOSE

Up to now in maxillofacial surgery almost all inpatient treatments were reimbursed at the hospital's per diem rate. The real treatment cost is unknown and there is a lack of publications in this sphere. This study calculates the cost of surgical treatment of mandibular fractures.

METHOD

The prospective study includes 104 patients whose mandibular fractures were treated using miniplate osteosynthesis. For each patient we took into account the time input by physicians and specialised nurses and calculated labour cost using the relevant wage rates. We added the cost for materials and drugs as well as for laboratory and radiographic examinations. Finally, we incorporated charges for the hotel and nursing components of inpatient treatment.

RESULTS

The cost for the surgical treatment of mandibular fractures varied between 642 euro; for single and 1,070 euro; for triple fractures. The share of labour cost is about 1/3. Treatment cost varies with the length of hospital stay: 1,132 euro; for four days and 1,628 euro; for seven days on average.

CONCLUSION

This prospective study can be compared with the recently published corresponding G-DRG rates. Moreover, the reported cost figures allow comparison with corresponding cost studies from other public health systems.

Reply to: Econometric issues in testing the age neutrality of health care expenditure

Salas and Raftery allege that in our paper, (1) remaining life expectancy is an endogenous explanatory variable of health care expenditure and (2) the parameter designed to correct for sample selection bias in fact represents a hidden relationship between health care expenditure and age. We argue that claim (1) is not supported by the available empirical evidence, while claim (2) seems to derive from a too cursory reading of our paper.

The nucleus-encoded HCF107 gene of Arabidopsis provides a link between intercistronic RNA processing and the accumulation of translation-competent psbH transcripts in chloroplasts

To understand the functional significance of RNA processing for the expression of plastome-encoded photosynthesis genes, we investigated the nuclear mutation hcf107 of Arabidopsis. The mutation is represented by two alleles, both of which lead to a defective photosystem II (PSII). In vivo protein labeling, in vitro phosphorylation, and immunoblot experiments revealed that the psbB gene product (CP47) and an 8-kD phosphoprotein, the psbH gene product (PsbH), are absent in mutant plants. PsbH and PsbB are essential requirements for PSII assembly in photosynthetic eukaryotes, and their absence in hcf107 is consistent with the PSII-less mutant phenotype. RNA gel blot hybridizations showed that the hcf107 mutation specifically impairs the accumulation of some but not all oligocistronic psbH transcripts that are released from the pentacistronic psbB-psbT-psbH-petB-petD precursor RNA by intergenic endonucleolytic cleavage. In contrast, neither the levels nor the sizes of psbB-containing RNAs are affected. S1 nuclease protection analyses revealed that psbH RNAs are lacking only where psbH is the leading cistron and that they are processed at position -45 in the 5' leader segment of psbH. These data and additional experiments with the cytochrome b(6)f complex mutant hcf152, which is defective in 3' psbH processing, suggest that only those psbH-containing transcripts that are processed at their -45 5' ends can be translated. Secondary structure analysis of the 5' psbH leader predicted the formation of stable stem loops in the nonprocessed transcripts, which are unfolded by processing at the -45 site. We propose that this unfolding of the psbH leader segment as a result of RNA processing is essential for the translation of the psbH reading frame. We suggest further that HCF107 has dual functions: it is involved in intercistronic processing of the psbH 5' untranslated region or the stabilization of 5' processed psbH RNAs, and concomitantly, it is required for the synthesis of CP47.

[Evaluation of the public health service law of the Saxony-Anhalt region--community affairs, transfer of power and loss of control]

AIM

In the state of Saxony-Anhalt, a new Public Health Service law came into force in 1998. Our study investigated whether this new legislation has led to an extension of duties performed by regional health departments and to a subsequent increase in expenditure.

METHODS

Guided interviews at all administrative levels of the public health system were conducted. The catalogue of duties was systematized and a questionnaire was developed and distributed to all regional health departments (response rate: 17 out of 24). Data concerning revenues and expenditures of the regional health departments were analysed on the basis of the administrative districts' budget data.

RESULTS

Regional health departments stated that there had been practically no change in their activities over the last few years. When questioned about the coverage of 58 specific duties, a considerable disparity was evident between departments. A core group of "classical" duties comprising environmental health and hygiene, child health protection, individual health appraisal, and public health supervision are carried out on an established basis. Some duties were handled by external institutions, others, mostly community health duties, were not performed on an extensive scale. When asked about the desired model for their health department, most departments preferred the model of being an executor of sovereign duties, however a corporate model was deemed to be almost as acceptable. The following fields will gain increasing significance in the future: environmental medicine, health reporting, preventive medicine, co-ordination of regional health care, and health promotion. Since 1995, staff has been reduced in all regional health departments (-10.4%; 1999: 2.92 employees per 10,000 inhabitants). In 1999, expenditures amounted to an average of 24.64 German Marks per capita (range 14.20-44.58 DM). The number of inhabitants and the revenue of the regional districts were determinants of their health budgets.

CONCLUSION

Our results showed that no uncompensated additional expenditure by regional authorities resulted from this law. So far, most districts have not perceived regional health as a community affair offering possible competitive advantages. The federal state lost considerable influence at the regional level. Recommended are regional health priorities, conjoint staff development, and state guidance by a head agency providing leadership and support, while leaving responsibility with the districts.

Health care expenditure in the last months of life

In OECD countries, a considerable share of health care expenditure (HCE) is spent for the care of the terminally ill. This paper derives the demand for HCE in the last 2 years of life from a model that accounts for age, mortality risk and wealth. The empirical tests are based on data of deceased members of a major Swiss sick fund. The empirical evidence confirms most of the hypotheses derived from the model, i.e., (i) HCE increases with closeness to death, (ii) for retired individuals, HCE decreases with age, and (iii) low-income individuals, as compared to high-income individuals, incur lower HCE in the last months of life.

Ageing of population and health care expenditure: a red herring?

This paper studies the relationship between health care expenditure (HCE) and age, using longitudinal rather than cross-sectional data. The econometric analysis of HCE in the last eight quarters of life of individuals who died during the period 1983-1992 indicates that HCE depends on remaining lifetime but not on calendar age, at least beyond 65+. The positive relationship between age and HCE observed in cross-sectional data may be caused by the simple fact that at age 80, for example, there are many more individuals living in their last 2 years than at age 65. The limited impact of age on HCE suggests that population ageing may contribute much less to future growth of the health care sector than claimed by most observers.

Combinatorial chemistry reveals a new motif that binds the platelet fibrinogen receptor, gpIIbIIIa

Among cell adhesion molecules, the classic Arg-Gly-Asp (RGD) motif is the best studied. We used combinatorial chemical and affinity immunochemical methods to find a novel motif of unnatural peptide ligands for the fibrinogen receptor of platelets, gpIIbIIIa (alphaIIbbeta3). The new d-amino acid motif, p(f/y)l, is unique among the ligands that bind the RGD pocket: It lacks the carboxylic acid group that is believed to coordinate with calcium in the MIDAS motif of the receptor. With an IC50 of 14 microM for the most potent compound, these linear p(f/y)l peptides had affinities similar to those of linear peptides containing RGD, and reversed sequences failed to compete with binding up to 1 mM. As the new motif was so different, molecular modeling was employed to suggest a model for molecular recognition. A reversed binding mechanism common for d-amino acid mimics of natural l-amino acid peptides offers an attractive hypothesis that suggests three points of contact similar to those made by the RGD-mimicking monoclonal antibody, OPG2. Interestingly, the model proposes that pi-electrons in the new motif may substitute for the carboxylate group present in all other RGD-types of ligands. Although modeling linear peptides is subjective, the pi-bonding model provides intriguing possibilities for medicinal chemistry after appropriate confirmatory studies.

Costs of dying: alternatives to rationing

In western industrialised countries, about 30% of health-care expenditure of retired people is incurred by individuals in their last year of life. The corresponding high costs of dying have led medical philosophers to ask for a rationing of health-care services according to age. By contrast, this paper pursues an individualistic approach. High costs of dying are identified as a consequence of moral hazard on both the demand and supply side of the health-care sector. Health insurance prevents demand for health-care services from decreasing when an individual's residual life expectancy shrinks. Age-related moral hazard can be limited by a coinsurance scheme with a deductible that increases with the age of the insured. Given the high costs of dying, the optimal insurance policy links the coinsurance rate to the age-specific mortality risk.

One-bead-one-structure combinatorial libraries

Combinatorial libraries employing the one-bead-one-compound technique are reviewed. Two distinguishing features characterize this technique. First, each compound is identified with a unique solid support, enabling facile segregation of active compounds. Second, the identity of a compound on a positively reacting bead is elucidated only after its biological relevance is established. Direct methods of structure identification (Edman degradation and mass spectroscopy) as well as indirect "coding" methods facilitating the synthesis and screening of nonpeptide libraries are discussed. Nonpeptide and "scaffold" libraries, together with a new approach for the discovery of a peptide binding motif using a "library of libraries," are also discussed. In addition, the ability to use combinatorial libraries to optimize initially discovered leads is illustrated with examples using peptide libraries.

Human neutrophil motility: time-dependent three-dimensional shape and granule diffusion

The locomotion of human polymorphonuclear leukocytes (PMNs) was studied with two complementary methods: Three-dimensional shapes were reconstructed from time series of optical sectioning microscopy using differential interference contrast (DIC) optics, and the diffusion of cytoplasm granules within individual cells was measured using quasielastic laser light scattering (QELS). The three-dimensional cell edges outlined in the optical sections were analyzed qualitatively in time-lapse film strips and quantitatively from morphometry. The fastest locomotion occurred in chemotactic gradient with cell velocity that oscillated between 10 and 30 microns/min with a period of 50-55 seconds. Within the periodic bursts of speed, a fibroblast-like locomotory cycle was observed, with leading lamella extended and contacts formed with the substrate surface, followed by rapid motion of the cell body and nucleus over the immobile contacts. Consistent with this apparent staged motion, correlation analysis revealed a phase lag of 2-3 seconds in velocities between the bottom (ventral) and the top layers of the cell. In addition there was a tendency to a lower cell profile at times of higher velocity. The diffusion of natural cytoplasmic granules within resting PMNs was not affected by cytoskeleton disrupting drugs. During the stage of most rapid motion, when cytoplasmic streaming could be seen, diffusion of the granules decreased two- to 2.5-fold, and then returned to resting levels. These observations suggest that PMN locomotion consists of extensions near the surface to form forward contacts and then stiffening or possibly contraction of the cytoskeleton when the body of the cell is moved forward. Three-dimensional movies of PMN cells are included in the video supplement.

One bead, one chemical compound: use of the selectide process for anticancer drug discovery

A technology for chemical synthesis and testing of libraries of millions of chemical entities has been developed for rapid molecular and cellular screening for drug leads. Each individual compound in the library is on a separate resin bead. Screening for binding activity can be conducted directly on the beads. Biological activity is assessed in solution phase assay by cleaving a portion of the compound from each bead. The molecular structure of the compound of interest is obtained by automated peptide sequencing from the bead of origin. We have applied this technology to anticancer drug discovery as well as to other pharmaceutical targets. For anticancer drug development, current molecular targets include B-cell lymphoma, the EGF receptor, and the HER2-neu receptor. Solution phase screening with dual cleavable libraries is being used for growth inhibition of human tumor cell lines. Initial in vitro leads have been identified in each of these areas of anticancer drug discovery.

Real-time measurements of kinetics of EGF binding to soluble EGF receptor monomers and dimers support the dimerization model for receptor activation

We have tested one aspect of the allosteric dimerization model for the activation of EGF receptor (EGFR) by EGF: whether EGF binding favors dimerization of the receptor. For this to be true, EGF molecules must bind with higher affinity to dimeric receptors than to monomeric receptors. We have tested this directly in a defined system using the soluble, extracellular ligand binding domain of EGFR monomers (sEGFR) and sEGFR dimers stabilized by treatment with a covalent cross-linking agent. We describe real-time kinetic measurements of EGF binding to receptor monomers and dimers employing the method of total internal reflection (surface plasmon resonance). Our data show that sEGFR dimers bound EGF with 30-40-fold higher affinity [KD = (2-3) x 10(-8) M] than did sEGFR monomers. The enhanced binding affinity of sEGFR dimers resulted mainly from a reduced off-rate with k(off) = 0.001 s-1 for sEGFR dimers as compared to k(off) = 0.06 s-1 for sEGFR monomers. These measurements indicate that dimerization of sEGFR increases its affinity for EGF by prolonging the amount of time that EGF remains bound to the receptor. This provides evidence that EGF binding stabilizes receptor dimerization and provides further support for the allosteric dimerization model as a mechanism for ligand induced receptor activation.

SH2 domains exhibit high-affinity binding to tyrosine-phosphorylated peptides yet also exhibit rapid dissociation and exchange

src homology 2 (SH2) domains of intracellular signaling molecules such as phospholipase C-gamma and phosphatidylinositol 3'-kinase-associated protein p85 represent recognition motifs for specific phosphotyrosine-containing regions on activated growth factor receptors. The binding of SH2 domains to activated growth factor receptors controls the interaction with signaling molecules and the regulation of their activities. In this report, we describe the kinetic parameters and binding affinities of SH2 domains of p85 toward short phosphotyrosine-containing peptides with the amino acid sequence motif YMXM, derived from a major insulin receptor substrate, IRS-1, by using real time biospecific interaction analysis (BIAcore). Associations were specific and of very high affinity, with dissociation constants of 0.3 to 3 nM, between phosphopeptides and the two separate SH2 domains contained within p85. Nonphosphorylated peptides showed no measurable binding, and the interactions were specific for the primary sequence very close to the phosphotyrosine residue. Moreover, the interactions between phosphopeptides and SH2 domains of other signaling molecules were of much lower affinity. Interestingly, the binding of the SH2 domains to the tyrosine-phosphorylated peptides was of high affinity as a result of a very high on rate, of 3 x 10(7) to 40 x 10(7)/M/s; at the same time, the rate of dissociation, of 0.11 to 0.19/s, was rapid, allowing for rapid exchange of associating proteins with the tyrosine phosphorylation sites.

Hypothalamic lesions that induce female precocious puberty activate glial expression of the epidermal growth factor receptor gene: differential regulation of alternatively spliced transcripts

Injury of the nervous system triggers a complex series of repair mechanisms that include production of neurotrophic and mitogenic factors by cells neighboring the injured area. While trauma of most parts of the brain results in loss of function, lesions of certain regions of the female hypothalamus enhance the secretory activity of a group of specialized neurons that produce luteinizing hormone-releasing hormone (LHRH), the neuropeptide that controls sexual development. The increased output of LHRH causes sexual precocity by prematurely activating the neuroendocrine reproductive axis. Recent studies have implicated transforming growth factor alpha (TGF alpha) produced by reactive astrocytes in the process by which lesions hasten sexual maturation, and have suggested that the stimulatory actions of TGF alpha on LHRH neurons require the intermediacy of epidermal growth factor receptors (EGFRs). In the present study, we examined the changes in EGFR gene expression following lesions of the preoptic-anterior hypothalamic area (POA-AHA) of immature female rats, identified the cell types where EGFR synthesis increases, and assessed the biochemical activity of the newly formed EGFR protein. RNase protection assays demonstrated that the lesion significantly increased the levels of a predominant mRNA transcript encoding the full-length, membrane-spanning EGFR, but did not affect those of a much less abundant, alternatively spliced mRNA that encodes a truncated, presumably secreted form of EGFR. Following lesions, antibody-induced EGFR kinase activity increased twofold. Antibodies directed against a peptide sequence contained within the carboxy terminus of EGFR showed intense EGFR immunoreactivity in cells surrounding the lesion site; double immunohistochemistry identified these cells as astrocytes since EGFR immunoreactivity was colocalized with that of glial fibrillary acidic protein, an astrocytic marker. That these changes result from an increase in EGFR gene expression was indicated by the elevated levels of EGFR mRNA detected by in situ hybridization in cells of the same area. Although POA-AHA lesions did not result in appearance of EGFR in LHRH neurons themselves, EGFR-positive cells and processes were seen in close proximity to LHRH neurons and their nerve terminals, particularly in the area surrounding the lesion. Since TGF alpha gene expression is also increased in reactive astrocytes of POA-AHA lesions and blockade of EGFR prevented the advancing effect of the lesion on puberty (Junier et al., 1991b), the present results support the concept that, in lesioned animals, TGF alpha stimulates LHRH secretion indirectly via a paracrine mechanism that involves its interaction with EGFRs located on astroglial cells.

Annexin I is phosphorylated in the multivesicular body during the processing of the epidermal growth factor receptor

We have previously shown that an active epidermal growth factor receptor (EGF-R) kinase is necessary for efficient sorting of the EGF-R to the lysosome, and we have shown that this occurs in the multivesicular body (MVB), where EGF-R are sorted away from recycling receptors by being removed to the internal vesicles of the MVB. The aim of the present study was to identify substrates of the EGF-R kinase associated with MVBs which might play a role in this sorting process. We used a density shift technique to isolate MVBs and show that the major substrates phosphorylated in vitro within MVBs which contain an active EGF-R kinase are the EGF-R itself and annexin I. Annexin I is associated with both plasma membrane and MVBs in a calcium-independent manner but can be phosphorylated in vitro only in MVBs. Phosphorylation of calcium-independent annexin I in isolated MVBs converts it to a form that requires calcium for membrane association. In cells with an active EGF-R kinase the amount of calcium-independent annexin I in MVBs is reduced, suggesting that a phosphorylation-induced conversion of the calcium independent to the calcium-dependent form also occurs in vivo. Our observations, together with the known properties of annexin I in mediating membrane fusion, suggest that inward vesiculation in MVBs is induced by the EGF-R and is mediated by phosphorylated annexin I.

Kinetics of binding, endocytosis, and recycling of EGF receptor mutants

This report describes analysis of factors which regulate the binding of EGF to EGF receptor, receptor internalization, and receptor recycling. Three different methods were used to inhibit high-affinity EGF binding as measured at equilibrium: treatment of cells with an active phorbol ester (PMA), binding of a mAb directed against the EGF receptor (mAb108), and truncation of most of the cytoplasmic domain of the receptor. These treatments reduced the rate at which low concentrations of EGF bound to cells, but did not affect the rate of EGF dissociation. We conclude that high-affinity EGF binding on living cells results from a difference in the apparent on rate of EGF binding. We then used these conditions and cell lines to test for the rate of EGF internalization at different concentrations of EGF. We demonstrate that internalization of the EGF receptor is stimulated roughly 50-fold at saturating concentrations of EGF, but is stimulated an additional two- to threefold at low concentrations (less than 1 nM). Four treatments reduce the rate of internalization of low concentrations of EGF to the rate seen at saturating EGF concentrations. Phorbol ester treatment and mAb108 binding to "wild type" receptor reduce this rate (and reduce high-affinity binding). Point mutation at Lys721 (kinase negative EGF receptor) and point mutation at Thr654 (removing a major site of protein kinase C phosphorylation) reduce the internalization rate, without affecting high-affinity binding. We suggest that while EGF stimulates endocytosis for all receptors, high-affinity receptors bind and are internalized more quickly than low-affinity receptors. Tyrosine kinase activity and the Thr654 region appear necessary for this response.

Cloning of the human serotonin 5-HT2 and 5-HT1C receptor subtypes

We report the cloning and the deduced amino acid sequence of cDNAs encoding both the human serotonin 5-HT2 and 5-HT1C receptors. The human 5-HT2 and 5-HT1C receptors shared 87% and 90% amino acid homology, respectively, with their rat counterparts. The most divergent regions of the 5-HT2 receptor between human and rat were the N-terminal extracellular domain (75% homology) and the C-terminal intracellular domain (67% homology between amino acids 426-474). The greatest variability between the human and rat 5-HT1C receptors were at the N-terminal extracellular domain (78% homology) and the third cytoplasmic loop (71% homology). The availability of the cloned human 5-HT2 and 5-HT1C receptors will help facilitate the further understanding of the molecular pharmacology and physiology of these receptors.

EGF induces increased ligand binding affinity and dimerization of soluble epidermal growth factor (EGF) receptor extracellular domain

The binding of epidermal growth factor (EGF) to its cell surface receptor (EGF-R) results in a number of intracellular responses including the activation of the receptor intracellular tyrosine kinase. Receptor oligomerization induced by ligand binding has been suggested to play an important role in signal transduction. However, the mechanisms involved in oligomerization and signal transduction are poorly understood. We have produced and purified several milligrams of recombinant extracellular domain of the EGF receptor (EGF-Rx) using the baculovirus/insect cell expression system. The baculovirus-generated EGF-Rx is glycosylated, has had its signal peptide correctly cleaved, and exhibits a dissociation constant for EGF similar to that for solubilized full-length receptor, of about 100 nM. The binding of EGF to EGF-Rx leads to the formation of receptor dimers and higher oligomerization states which are irreversibly captured using the covalent cross-linking agent disuccinimidyl suberate. Interestingly, purified receptor monomers and dimers, stabilized by the cross-linker in the presence of EGF, exhibit increased binding affinity toward EGF as compared with receptor monomers which have not been exposed to EGF. It appears that the high affinity state of receptor can be maintained by the covalent cross-linking agent. These results indicate that in addition to ligand binding, the extracellular domain of EGF receptor possesses the inherent ability to undergo ligand-induced dimerization and that the low affinity state is converted to a high affinity state by EGF.

Analysis of platelet-derived growth factor receptor domain function using a novel chimeric receptor approach

A chimeric receptor consisting of an epidermal growth factor (EGF) receptor ligand-binding domain and platelet-derived growth factor (PDGF) receptor transmembrane and cytoplasmic signalling domains has been constructed and shown to be fully functional in phosphorylation, mitogenesis, transformation, Ca2+ release, and pH change assays. Expression of this receptor in EGF receptor-deficient, PDGF-responsive NIH 3T3 cells allows the activation of PDGF signalling pathways by EGF. This system was used to examine the function of kinase insertion sequences (KIS). While a mutant with a KIS deletion of 83 amino acids displayed a significant but reduced ability to induce mitogenic, transforming, and Ca2+ release responses in transfected cells, deletion of 20 additional amino acids resulted in abolishment of such activities. This differential loss of signalling potential correlated with the reduced or abolished potential of these receptor mutants to phosphorylate cellular substrates such as PLC gamma. Our results suggest an integral role for KIS in PDGF receptor cytoplasmic domain conformation and an involvement in substrate interaction, but provide no evidence for an exclusive role of KIS in the mediation of biological signals.

Klippel-Trenaunay-Weber syndrome with recurrent pulmonary embolism

A man with Klippel-Trenaunay-Weber syndrome had worsening pulmonary hypertension secondary to recurrent multiple pulmonary embolism despite anticoagulation. Pulmonary thromboendarterectomy was done. However, the patient expired 10 days after surgery due to another bout of pulmonary embolism from his right arm or right chest wall.

Cloning and expression of the human substance K receptor and analysis of its role in mitogenesis

The primary structure of the human substance K receptor was established from the sequences of complementary DNA clones isolated from a human jejunal complementary DNA library. It consists of 398 amino acids, including seven putative transmembrane regions. The gene for the human substance K receptor was localized to chromosome region 10p13-10q23, a region with frequent chromosomal abnormalities. The human substance K receptor was expressed in transfected NIH-3T3 cells lacking endogenous substance K receptors, and Scatchard analysis of 125I-labeled substance K binding indicates approximately 100,000 receptors/cell with a single dissociation constant of 12 nM. Covalent cross-linking experiments utilizing 125I-substance K and three different chemical cross-linking reagents (disuccinimidyl suberate, disuccinimidyl tartrate, or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-HCl) demonstrate an apparent molecular weight of 45,000, consistent with little or no N-linked glycosylation. The binding of substance K to its receptor on transfected cells led to a rapid increase in the production of total inositol phosphates and the release of Ca2+ from internal stores. Growth of the cells transfected with the human substance K receptor is stimulated by the addition of substance K to the medium to a level similar to 10% serum. Therefore, the human substance K receptor can function as a growth factor receptor when expressed in mouse 3T3 cells.