Frequency and costs of technical failures of clasp- and double crown-retained removable partial dentures

OBJECTIVES

The aim of this study was to evaluate the frequency of technical failure rates and the maintenance costs of clasp- or double crown-retained removable partial dentures (RPDs) (parallel-sided and conical double crowns).

MATERIAL AND METHODS

According to three different retainer systems used between January 1992 to December 1998, three subgroups were randomly assigned from a group of 181 patients consisting of forty cases each. The average observation time was 4.2+/-1.7 years, with a minimum of 1.0 years and a maximum of 6.9 years. Technical complications such as fractures of the artificial teeth, loss of cementation, loss of facings as well as fractures of the metal framework and the soldering were recorded due to the medical reports.

RESULTS

Twenty percent of all clasp-retained dentures showed technical complications during the observation period, whereas 50% of conical crown-retained (CC) and 32.5% of the parallel-sided retained dentures (PS) required repair. Most often reported was loss of cementation for double crowns (n=13, 32.5% PS; n=8, 20% CC) and fractures of the clasps (n=5). Although clasp-retained dentures had a markedly lower frequency of failures (n=8) than double crown systems (n=31), the calculated repair costs per event during the observation time were more than twice as high for clasp-retained dentures (172.5 Euro) than for double crown systems (8-78 Euro). The hypothesis that the maintenance costs of the more sophisticated double crown system are higher must be rejected.

A study of cranial computer tomograms in very early and early onset schizophrenia

The cranial computer-assisted tomograms of 19 patients suffering from schizophrenic psychoses with onset by age of 14 were examined. The emphasis was on the extent of the inner liquor spaces. Compared to healthy controls, at the beginning of illness a significant enlargement was revealed only in the patient group with very early onset schizophrenia (VEOS, onset prior to the age of 12), whereas children with early onset (EOS, 12 to 14 years of age) showed no significant brain pathology. As a second result, an increase in the extent of the inner liquor spaces seems to correlate with the duration of illness. It is therefore concluded that psychoses interfere with neurodevelopmental processes and cause more severe brain pathology in very young children, already detectable at the onset of the illness. EOS, on the other hand, induces progressive morphological abnormalities over the course of the illness.

The 15-kDa forms of the apo-peridinin-chlorophyll a protein (PCP) in dinoflagellates show high identity with the apo-32 kDa PCP forms, and have similar N-terminal leaders and gene arrangements

Full-length genomic sequences encoding apo peridinin-chlorophyll a proteins (PCPs) from Heterocapsa pygmaea have been obtained by PCR. Two of the derived mature proteins of 150 residues have molecular masses of 15,795 and 15,780, respectively. Contrary to an earlier report, these show a high degree of identity (approximately 70%) over the whole of both domains to the mature 32-kDa PCP forms. The two genes lack introns, are arranged in tandem and separated by 526 bp. A putative N-terminal extension with three domains characteristic of a signal sequence, a chloroplast-targeting sequence and a thylakoid lumen-directing sequence, is present. Modelling of the Heterocapsa PCP amino acid sequence on to the high-resolution structure available for Amphidinium PCP shows that the main differences between two forms are in trimer contact regions.

What can medicine learn from the human DNA sequence?

The cooperation of biochemistry with clinical medicine consists of two overlapping temporal phases. Phase 1 of the cooperation, which still is not finished, is characterized by joint work on the pathogenesis and diagnostics of systemic metabolic diseases, whereas in phase 2 the cooperation on tissue and cell specific as well as on molecular diseases is prevailing. In view of the conceptual revolution and shift in paradigm, which biochemistry and medicine are presently experiencing, the content of cooperation between the two disciplines will profoundly change. It will become deeply influenced by the results of the research into the human genome and human proteome. Biochemistry will strongly be occupied to relate the thousands of protein coding genes to the structure and function of the encoded proteins, and medicine will be concerned in finding new protein markers for diagnostics, to identify novel drug targets, and to investigate, for example, the proteomes of the variety of tumors to aid tumor classification, to mention only a few areas of interest which medicine will have in the progress of human genome research. The review summarizes the recent achievements in sequencing the human DNA as published in February 2001 by the International Human Genome Sequencing Consortium and Celera Genomics and discusses their significance in respect to the further development of molecular, in particular genetic, medicine as an interdisciplinary field of the modern clinical sciences. Only biochemistry can provide the conceptual and experimental basis for the causal understanding of biological mechanisms as encoded in the genome of an organism.

Transvenous embolization of carotid cavernous fistulas via the superior ophthalmic vein

BACKGROUND

Treatment of choice for symptomatic carotid-cavernous and cavernous-dural fistulas is neuroradiologic intervention via the femoral artery. Owing to the location of the fistula and/or to anatomic variations, a direct surgical approach via the superior ophthalmic vein may be necessary for embolization.

METHODS

Three patients presented with exophthalmos, episcleral venous congestion, chemosis, restricted eye movement, and secondary glaucoma. One patient had visual impairment and scotoma due to compression of the optic nerve by the fistula. The tentative diagnosis of an arteriovenous fistula was confirmed in two cases by color Doppler imaging and in all three cases with cerebral arterial angiography (two carotid-cavernous fistulas, one cavernous-dural fistula). After an unsuccessful transarterial attempt, embolization via the superior ophthalmic vein was chosen.

RESULTS

In all three patients the preparation of the superior ophthalmic vein was performed without any complications. In two cases the fistula could be embolized completely with platinum coils. In one patient the placement of the microcatheter was impossible, because of an abnormal vascular pattern. Later on the fistula was successfully embolized by an approach via the femoral vein. All three patients had complete resolution of symptoms. There were no recurrences.

CONCLUSION

Embolization of carotid-cavernous and cavernous-dural fistulas by a surgical approach via the superior ophthalmic vein represents safe and effective treatment when standard transarterial access is impossible. The cooperation of an orbital surgeon and an invasive neuroradiologist can be of benefit for this rare group of patients.

Early postoperative transcranial sonography (TCS), CT, and MRI after resection of high grade glioma: evaluation of residual tumour and its influence on prognosis

PURPOSE

In this prospective study the results of multimodal postoperative neuro-imaging were related to the survival of patients with high grade gliomas.

METHODS

All 73 patients included underwent microsurgical tumour resection and had postoperative CT and transcranial sonography (TCS) examinations. In addition, 35 of the 73 patients received an early postoperative MRI. Patients were followed up for at least one year.

FINDINGS

At the end of the 7 year study period 56 patients had died. The median survival time was 371 days. Survival rate was significantly higher in patients with anaplastic astrocytomas and inpatients displaying complete tumour resection on MRI (log-rank-test, p < 0.05) or a small postoperative residual tumour bulk on TCS (log-rank-test, p < 0.05). Cox proportional hazards model identified histological tumour grade, postoperative Karnofsky index, complete resection based on MRI and small postoperative residual tumour mass on TCS as independent predictors of survival.

INTERPRETATION

This study demonstrates that early postoperative neuro-imaging has prognostic implications for the survival of patients with high grade gliomas. According to our results postoperative imaging with MRI and TCS is a valuable prognostic with regard to patient survival and should therefore be implemented in postoperative follow-up. It also helps to evaluate the efficacy of adjuvant therapy.

Characterization of transmembrane segments 3, 4, and 5 of MalF by mutational analysis

MalF and MalG are the cytoplasmic membrane components of the binding protein-dependent ATP binding cassette maltose transporter in Escherichia coli. They are thought to form the transport channel and are thus of critical importance for the mechanism of transport. To study the contributions of individual transmembrane segments of MalF, we isolated 27 point mutations in membrane-spanning segments 3, 4, and 5. These data complement a previous study, which described the mutagenesis of membrane-spanning segments 6, 7, and 8. While most of the isolated mutations appear to cause assembly defects, L(323)Q in helix 5 could interfere more directly with substrate specificity. The phenotypes and locations of the mutations are consistent with a previously postulated structural model of MalF.

Cerebral activation patterns in patients with writer's cramp: a functional magnetic resonance imaging study

Functional MRI (fMRI), visualizing changes in cerebral blood oxygenation, has to date not been performed either in patients with writer's cramp or in healthy subjects during writing. We compared the cerebral and cerebellar activation pattern of 12 patients with writer's cramp during writing with a group of 10 healthy subjects performing the same tasks over 30-s periods of rest or writing. Sixty echo planar imaging multislice datasets were analysed using SPM96 software. Data were analysed for each subject individually and groupwise for patients vs. controls. Healthy subjects showed a significant activation of the ipsilateral dentate nucleus, contralateral cerebellar hemisphere, contralateral primary sensorimotor cortex, and contralateral precentral gyrus during writing. Patients with writer's cramp showed significantly greater activation of the ipsilateral cerebellar hemisphere than controls. Also the activation in the primary sensorimotor cortex extended further caudally and anteriorly towards the premotor association area. Activation was observed in the thalamus during writing only among the patients. Our results indicate an increased basal ganglia output via the thalamus to the motor and premotor cortical areas in dystonia patients and support the notion of disinhibition of the motor cortex leading to cocontractions and dystonic postures.

[Dynamic MRI imaging of orbital diseases and ocular motility disorders]

High temporal and spatial resolution has recently been achieved by rapid magnetic resonance imaging techniques. This offers the opportunity to perform dynamic magnetic resonance imaging in addition to topographic imaging and tissue analysis. Using sequences obtained by turbo-fast low-angle shot imaging we have reduced temporal resolution to 1 s per image.

Is there a benefit of preoperative meningioma embolization?

OBJECTIVE

To evaluate the effect of preoperative embolization of meningiomas on surgery and outcomes.

METHODS

In a prospective study, 60 consecutive patients with intracranial meningiomas who were treated in two neurosurgical centers were included. In Center A, embolization was performed for none of the patients (n = 30). In Center B, 30 consecutive patients with embolized meningiomas were treated. Preoperatively, tumor size and location, neurological status, and Barthel scale score were recorded. In Center B, the extent of tumor devascularization was evaluated using angiography and postembolization magnetic resonance imaging. Intraoperatively, blood loss, the numbers of blood units transfused, and the observations of the neurosurgeon concerning hemostasis, tumor consistency, and intratumoral necrosis were recorded. Postoperatively, the neurological status and duration of hospitalization were recorded. Six months after surgery, the outcomes were assessed using the Barthel scale and neurological examinations.

RESULTS

The mean tumor sizes were 22.9 cc in Center A and 29.6 cc in Center B (P > 0.1). The mean blood losses did not differ significantly (646 ml in Center A versus 636 ml in Center B; P > 0.5). However, for a subgroup of patients with subtotal devascularization (>90% of the tumor) on postembolization magnetic resonance imaging scans in Center B, blood loss was less, compared with the entire group in Center A (P < 0.05). The observations of the neurosurgeon regarding hemostasis, tumor consistency, and intratumoral necrosis did not differ significantly. There were no surgery-related deaths in either center. The rates of surgical morbidity, with permanent neurological worsening, were 20% (n = 6) in Center A and 16% (n = 5) in Center B. There was one permanent neurological deficit (3%) caused by embolization.

CONCLUSION

In this preliminary study, only complete embolization had an effect on blood loss. The value of preoperative embolization for all meningiomas must be reconsidered, especially in view of the high costs and risks of embolization.

Cerebral activation pattern in primary writing tremor

OBJECTIVE

To compare the cerebral activation pattern during writing of patients with writing tremor with healthy controls using functional MRI METHODS: Three patients with writing tremor and 10 healthy controls were examined using a 1.5 Tesla scanner. All subjects performed a paradigm of alternating 30 second periods of rest or writing. For functional imaging 60 EPI multislice data sets were acquired. All images were analyzed using SPM96 software. Data were analyzed for the group of patients with writing tremor and compared with those of the control group.

RESULTS

Both patients with writing tremor and controls showed a significant activation of the contralateral primary sensorimotor cortex, SMA, and area 44. By contrast, motor cortex activation in writing tremor also included the contralateral premotor area (area 6) and ipsilateral prefrontal area (inferior frontal gyrus; areas 10, 44, and 47). Only patients with writing tremor showed a bilateral activation of the parietal lobule (area 40) with a more pronounced activation on the contralateral side. Furthermore, there was a bilateral activation of the cerebellum with a more pronounced area of activation on the ipsilateral side.

CONCLUSIONS

Brain areas activated in writing tremor included activation patterns otherwise typical for both essential tremor and writer's cramp. Therefore a distinct category for writing tremor integrating hallmarks of essential tremor and writer's cramp is proposed.

Cavum veli interpositi and psychotic disorder in a monocygotic twin

The case of monocygotic twins discordant for a psychotic disorder is presented. An anomaly of the septum pellucidum, a so-called cavum veli interpositi was found in the psychotic twin while his brother showed no such anomaly. Previous studies have shown a higher prevalence of septum pellucidum anomalies in schizophrenic patients. Abnormalities of the septum pellucidum may be associated with disturbed neuronal development in distinct limbic brain areas which cannot yet be visualized yet by brain imaging techniques. The finding of the cavum veli interpositi in the psychotic twin could be incidental; however, it may indicate a dysgenic process in early brain development and, thus, play a significant role in the etiology of psychosis.

A conserved structural motif for lipopolysaccharide recognition by procaryotic and eucaryotic proteins

BACKGROUND

Lipopolysaccharide (LPS), a lipoglycan from the outer membrane of Gram-negative bacteria, is an immunomodulatory molecule that stimulates the innate immune response. High levels of LPS cause excessive release of inflammatory mediators and are responsible for the septic shock syndrome. The interaction of LPS with its cognate binding proteins has not, as yet, been structurally elucidated.

RESULTS

The X-ray crystallographic structure of LPS in complex with the integral outer membrane protein FhuA from Escherichia coli K-12 is reported. It is in accord with data obtained using mass spectroscopy and nuclear magnetic resonance. Most of the important hydrogen-bonding or electrostatic interactions with LPS are provided by eight positively charged residues of FhuA. Residues in a similar three-dimensional arrangement were searched for in all structurally known proteins using a fast template-matching algorithm, and a subset of four residues was identified that is common to known LPS-binding proteins.

CONCLUSIONS

These four residues, three of which form specific interactions with lipid A, appear to provide the structural basis of pattern recognition in the innate immune response. Their arrangement can serve to identify LPS-binding sites on proteins known to interact with LPS, and could serve as a template for molecular modeling of a LPS scavenger designed to reduce the septic shock syndrome.

[IgA rheumatoid factor and prognosis in chronic polyarthritis]

We determined the prognostic value of IgA rheumatoid factor in patients with rheumatoid arthritis. The results show clearly that only patients with high titers of IgARF during their course had an unfavorable prognosis determined by functional status and mortality.

Technical failure rates of double crown-retained removable partial dentures

Removable partial dentures (RPD) can be retained using conical crowns or parallel-sided telescopic double crowns. The purpose of this study was to evaluate and compare the technical failure rate of the two retainer systems. One hundred seventeen dentures made by dentists of the medical school were included. Seventy-four RPD were retained with parallel-sided crowns (n = 251) and 43 with conical crowns (n = 160). Following the medical report follow-ups from January 1992 to December 1998, technical RPD failures were noted and analyzed. Technical problems occurred during the observation time in 48.8% of the conical retained dentures and 34.2% of the parallel-sided retained dentures. In both cases, loss of cementation was most frequently noted, while loss of the facings occurred only with conical crowns. Other technical failures did not depend on the type of retainer system used. These were most frequently problems with the denture base, e.g., fracture of artificial teeth or the metal framework. We conclude that there were different technical failures of both double crown retainer systems. These problems were not insignificant in number but treatable.

Peridinin chlorophyll a protein: relating structure and steady-state spectroscopy

Peridinin chlorophyll a protein (PCP) from Amphidinium carterae has been studied using absorbance (OD), linear dichroism (LD), circular dichroism (CD), fluorescence emission, fluorescence anisotropy, fluorescence line narrowing (FLN), and triplet-minus-singlet spectroscopy (T-S) at different temperatures (4-293 K). Monomeric PCP binds eight peridinins and two Chls a. The trimeric structure of PCP, resolved at 2 A [Hofmann et al. (1996) Science 27, 1788-1791], allows modeling of the Chl a-protein and Chl a-Chl a interactions. The FLN spectrum shows that Chl a is not or is very weakly hydrogen-bonded and that the central magnesium of the emitting Chl a is monoligated. Simulation of the temperature dependence of the absorption spectra indicates that the Huang-Rhys factor, characterizing the electron-phonon coupling strength, has a value of approximately 1. The width of the inhomogeneous distribution function is estimated to be 160 cm(-)(1). LD experiments show that the two Chls a in PCP are essentially isoenergetic at room temperature and that a substantial amount of PCP is in a trimeric form. From a comparison of the measured and simulated CD, it is concluded that the interaction energy between the two Chls a within one monomer is very weak, <10 cm(-)(1). In contrast, the Chls a appear to be strongly coupled to the peridinins. The 65 cm(-)(1) band that is visible in the low-frequency region of the FLN spectrum might indicate a Chl a-peridinin vibrational mode. The efficiency of Chl a to peridinin triplet excitation energy transfer is approximately 100%. On the basis of T-S, CD, LD, and OD spectra, a tentative assignment of the peridinin absorption bands has been made.