Novel Mutations in the Cathepsin C Gene in Patients with Pre-pubertal Aggressive Periodontitis and Papillon-Lefèvre Syndrome

Aggressive periodontitis (AP) in pre-pubertal children is often associated with genetic disorders like Papillon-Lefèvre syndrome (PLS). PLS is caused by mutations in the cathepsin C ( CTSC) gene. We report a novel CTSC mutation (c.566-572del) in an otherwise healthy AP child and two novel compound heterozygous mutations (c.947T>G, c.1268G>C) in a PLS patient. We conclude that at least a subset of pre-pubertal AP is due to CTSC mutations and therefore may be an allelic variant of PLS.

Biomechanics of the mandible and growth extension

BACKGROUND AND OBJECTIVE

One way of determining the direction of growth of the mandible is to consider the temporomandibular joint and movement of the mandible as a four-joint gear system, regarding growth then as an extension of the gear system. Our aim was to examine any correlations between the type of biomechanical growth extension and change in the maxilomandibular relation after Class II therapy.

SUBJECTS AND METHODS

A total of 130 lateral cephalograms-before and after orthodontic treatment-were available from 65 adolescent class II patients with open bite or deep bite. The two lateral cephalograms from each patient were superimposed on the occlusal plane. Cephalometric values and the vertical base point deviation were determined from biomechanical analyses, together with three distances and three angles.

RESULTS

No correlation between the cephalometric data and distances or angles were observed. Although there were no significant differences in the distances, we did note significant differences in all three angles (p < 0.05).

CONCLUSION

If gear system extension during growth is considered, this can be interpreted as meaning that the occlusal plane of those patients with an initially open bite dropped during treatment, but that it rose in patients with an initially deep bite.

How do spinal segments move?

PURPOSE

To study and clarify the kinematics of spinal segments following cyclic torques causing axial rotation (T(z) (t)), lateral-flexion (T(x) (t)), flexion/extension (T(y) (t)).

METHODS

A 6D--Measurement of location, alignment, and migration of the instantaneous helical axis (IHA) as a function of rotational angle in cervical, thoracic, and lumbar segments subjected to axially directed preloads.

RESULTS

IHA retained an almost constant alignment, but migrated along distinct centrodes. THORACIC SEGMENTS: IHA was almost parallel to T(z) (t), T(x) (t), or T(y) (t), stationary for T(x) (t) or T(y) (t), and migrating for T(z) (t) along dorsally opened bows. IHA locations hardly depended on the position or size of axial preload. LUMBAR SEGMENTS: IHA was also almost parallel to T(z) (t), T(x) (t), or T(y) (t). In axial rotation IHA-migration along wide, ventrally or dorsally bent bows depending on segmental flexional/extensional status. Distances covered: 20-60mm. In lateral-flexion: IHA-migration to the left/right joint and vice versa. In flexion/extension IHA-migration from the facets to the centre of the disc. CERVICAL SEGMENTS: In flexion/flexion IHA was almost stationary for and parallel to T(y) (t). In axial rotation or lateral-flexion IHA intersected T(z) (t)/T(x) (t) under approximately -30 degrees /+30 degrees.

CONCLUSIONS

Generally joints alternate in guidance. Lumbar segments: in axial rotation and lateral-flexion parametrical control of IHA-position and IHA-migration by axial preload position. Cervical segments: kinematical coupling between axial rotation and lateral-flexion. The IHA-migration guided by the joints should be taken into account in the design of non-fusion implants. FE-calculations of spinal mechanics and kinematics should be based on detailed data of curvature morphology of the articulating surfaces of the joint facets.

Cathepsin C Gene Variants in Aggressive Periodontitis

Cathepsin C ( CTSC) mutations are known to cause Papillon-Lefèvre syndrome. The aim of this study was to examine the association of CTSC genotype with susceptibility to non-syndromic aggressive periodontitis. The CTSC gene was analyzed in 110 persons with generalized aggressive periodontitis in comparison with 78 control individuals, after identifying different variants in a cohort of 100 persons. Five out of 19 discovered variants were included in this association study, representing 5 single-nucleotide polymorphism groups in tight linkage disequilibrium. The relevance of genotypes on enzyme function was examined. The carrier frequency of the missense variant p.I453V was significantly increased in persons with disease compared with healthy control individuals (17.3% vs. 6.4%, p < 0.05). CTSC activity in leukocytes from individuals harboring this variant was significantly reduced (119.8 ΔOD/min*105 cells, 95% confidence interval 17.4–174.9, p = 0.018). No influence of promoter variants was found on mRNA expression. The results support the hypothesis that CTSC gene variants contribute to increased susceptibility in generalized aggressive periodontitis.

Effect of bone conditioning on primary stability of FRIALIT-2 implants

BACKGROUND

Primary stability is crucial to implants used for orthodontic anchorage. Bone condensing to enhance primary stability is controversial.

MATERIAL AND METHODS

Fourteen Frialit-2-stepped screw and cylinder implants were placed in the median palatine sutures of 22 cadaveric human heads. In half of both types, the implant bed was prepared using a Frialit Bone Condenser. Primary implant stability was evaluated using non-invasive resonance frequency analysis. Moreover, the bone-implant contact area was examined histomorphometrically and radiographically.

RESULTS

Bone condensing yielded a slightly, yet not significantly increased implant stability quotient compared with a conventional technique. In spongy bone, a significant histomorphometric increase of bone-implant contact (P<0.0001) and a significant increase of radiographic density was revealed for both implant types, while no significant changes were observed within the compact area.

CONCLUSION

The study shows that bone condensing yields an improved histologic implant-bone contact only in spongy bone, which was paralleled by radiographic-densitometric findings.

Ritually induced growth disturbances and deformities of the orofacial system – A contribution to cranial morphogenesis

Numerous ritual acts involving the skull result in orofacial changes. The present study focuses on ritual acts of Brazilian Zoé Indians. A distinct deformation effect of the ritual act (wearing a lip-plug) on the morphology of the orofacial system is demonstrated and documented using jaw models. The studies show that the lip-plug significantly influences tooth position and jaw growth. While the maxilla displays palatal displacement of the lateral incisors and elevation of the palate, retraction occurs in the mandible depending upon plug size. Additionally, both the plug and the nutritional habits of the Indians induce marked abrasion of all teeth. Moreover, it is shown that the duration of lip-plug wear is an essential determinant of sustained orofacial changes.

The morphological and clinical relevance of mandibular and maxillary bone structures for implantation

Tooth loss, which interrupts the biocybernetic feedback circuit of the masticatory system, changes the structures of the jaw bone: such changes are termed "inactivity atrophy". The mandible is subject to vertical atrophy and the maxilla is primarily subject to horizontal atrophy. The mandible possesses more compact bone, the maxilla more spongy; the resorption directions also differ (mandible: towards the oral aspect; maxilla: towards the vestibular). An implant helps to restore the biocybernetic feedback system. The amount of available bone, bone structure, and topographic conditions are crucial factors influencing implant success. Osseointegration is performed at an early stage (which includes bleeding, granulation tissue, foreign-body recognition, interactions) and at a late stage (so-called osseous bridging, development of fibrous and lamellar bone).

Bone functions and the requirements for bone grafts and substitutes in the orofacial region

Bone is the largest calcium storage, has distinctive plasticity and adaptability and is part of the supporting tissue. An adequate composition is thus necessary. The bone matrix consists of organic and anorganic structures. Osteoblasts, osteoclasts and osteocytes are responsible for bone formation, resorption and metabolism. The periosteum, endosteum and bone tissue are a functional unit and provide protection, nutrition and growth. Bone is subject to continuous remodelling.

Histological and fluorescence microscopic examination of the bone/implant interface in orthodontic miniscrews (Mondeal)

The temporary nature of orthodontic implants demands optimisation of size and design in order to minimise damage and risk to the patient. Slender and shorter miniscrews offer the advantage over conventional implants of easier and more ubiquitous positioning with minimised risk of injury to neighbouring anatomical structures such as tooth roots, nerves or vessels. The question is raised, however, as to what extent these advantages are gained at the price of diminished stability or a more unfavourable bone interface. In order to evaluate the screw/bone interface, 14 orthodontic miniscrews (Mondeal Medical Systems, diameter: 1.5 mm, length: 9 mm) were inserted into the right and left mandibles of 7 pigs (Sus scrofa domestica). Bone fluorochromes were administered in a defined order for polychrome sequencing. The samples gathered after 70 days were analysed using histological techniques and fluorescence microscopy. The lower part of the self-tapping thread displayed undisturbed bone apposition. Fluorescence microscopy revealed remodelling and bone apposition within the thread grooves.

Bacterial colonisation of interior implant threads with and without sealing

Premature loss of dental implants is due, apart from mechanical factors, to germrelated inflammation. Gaps and hollow spaces within the implant system, for example the gap between implant and abutment in the two-part implant system, may provide a bacterial reservoir causing or maintaining inflammation. The bacterial spectrum involved is similar to that found in periodontitis. This in vitro study aimed to scrutinise the capability of Porphyromonas gingivalis (DSM 20709), the bacterium blamed for inducing peri-implantitis, to pass the implant/abutment gap in titanium implant systems used for orthodontic anchorage and to remain vital in the interior. Additionally, the in vitro effectiveness of gutta percha for gap sealing was examined. Twelve titanium implants (Straumann, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at a defined torque (20 Ncm), six of which were sealed with gutta percha before screwing in the abutment. Subsequently the implants were placed in a nutrient solution (thioglycolate boullion with haemin-menadione solution) that contained Porphyromonas gingivalis. Microbiological specimens were sampled from the implant interiors after 24 and 72 hours and analysed using culture methods. There was evidence that penetration of the periodontal pathogen Porphyromonas gingivalis to the implant interior may occur as early as after 24 hours. Microbes were also detected in the interior of implants sealed with gutta percha. The abutment/implant interface in vitro provides a microbiological leakage for the prospective peri-implantitis-inducing bacterium Porphyromonas gingivalis. Survival of the bacterium is possible in the interior, so that development of a bacterial reservoir is assumed. This in vitro trial produced no evidence that sealing with gutta percha is an effective means to prevent secondary bacterial colonisation in the implant interior.

Critical considerations on the diagnostic appraisal, adaptation and remodelling of bone graft substitutes

The diagnostic assessment of skeletal defects has a long-standing tradition. As a result of the development of new bone grafting materials, the demands on diagnostic assessment have also increased. The mode and quality of diagnostic appraisal are crucial to further clinical use and outcome prediction. Alongside traditional clinical and biological techniques, molecular biological methods have gained a broad scope of application and will be used even more frequently in the future.

The application of bone graft substitutes for alveolar ridge preservation after orthodontic extractions and for augmentation of residual cleft defects

The use of bone substitute materials in orthodontics is to be considered prior to orthodontic space closure after tooth extraction during the treatment of marked crowding as well as for treatment of residual defects in cleft-lip-and-palate children. In both cases the common objective is structure preservation or augmentation of the alveolar ridge. The demands to be made on the synthetic bone graft substitute comprise not just complication-free and safe use but also the chance of early tooth movement into the treated defect area with sufficient stability of the new tooth position.

Wound management after the application of bone grafting substitutes in the orofacial region

Surgical dressing after the application of bone grafting material depends on the type and size of the defect. A complete and tension-free wound closure has proved to be successful. In this context the infection problem needs special attention. Bone graft substitutes with an adequate surface structure, porosity and chemical properties, in combination with sufficient blood circulation, hold osteoconductive potential. They serve as a guide rail for the osteoblast-induced formation of new bone tissue, which at best may lead to complete replacement of the grafting material.

The in vitro viability and growth of fibroblasts cultured in the presence of different bone grafting materials (NanoBone and Straumann Bone Ceramic)

Different clinical applications, including dentistry, are making increasing demands on bone grafting material. In the present study we have analysed the viability, proliferation and growth characteristics of fibroblasts cultured in vitro together with two different bone grafting materials, NanoBone and Straumann Bone Ceramic, over a period of 24 and 28 days respectively. Viability was measured at least every 72 hours by using the alamarBlue assay, a test that measures quantitatively cell proliferation and viability but does not require cell fixation or extraction. After one week of culture fibroblast viability was as high as in controls for both grafting materials and remained high (> 90%) for the duration of the experiment. Cell growth was evaluated microscopically. Scanning electron microscopy revealed a dense fibroblast growth at the surface of both bone grafting materials after three weeks of in vitro culture. Generally, our in vitro analyses contribute to further insights into cell - scaffold interactions.

The use of ceramic drills on a zirconium oxide basis in bone preparation

The favourable mechanical properties and high biocompatibility of the newly developed mixed ceramics composed of zirconium oxide and aluminium oxide have continuously extended the scope of their application. Rotating instruments on a zirconium oxide basis are regarded as superior to metal burs in dentoalveolar surgery in terms of favourable temperature effects on the surrounding bone tissue and the economic advantage that they wear slowly, enabling them to be used repeatedly. In this study ten round burs made of zirconium oxide and aluminium oxide mixed ceramics were used for typical dental-alveolar preparation types on an explanted pig jaw. Prior to the first and following the tenth application a scanning electron microscopic (SEM) analysis of possible wear signs was conducted. However, this revealed no evidence of wear or resulting loss of sharpness.

The survival and proliferation of fibroblasts on orthodontic miniscrews with different surface treatment: an in vitro study

It is of fundamental importance for prosthodontic and orthodontic applications that there is a short osseointegration time of dental implants without inflammation of the surrounding tissue. In addition to the chemical properties of the implant material, the surface morphology is an equally critical parameter. The objective of this work was to study the effect of two simple surface treatments on the survival and proliferation of fibroblasts. Three groups of orthodontic miniscrews (Mondeal) were used. One group was given an airflow (EMS, Schweiz) treatment, the second was sand-blasted in the area of the threading and a third group served as a control. After preparation sterilised screws were cultured in vitro with fibroblasts (L-929). The metabolic cell activity on the implant surface was determined after 24, 48 and 120 hours using the alamarBlue assay and a count of DAPI labelled fibroblasts was performed with a fluorescence microscope. After 24 hours, but not at 48 hours and 120 hours, the metabolic activity of the fibroblasts was slightly decreased for the airflow screw group. Generally, no significant difference was found regarding metabolic activity and proliferation of fibroblasts within the different groups.

Requirements and infection prophylaxis for internally cooled implant drills

Implant site preparation is crucially important to long-term success. Heat generation during drilling is unfavourable, since bone is relatively susceptible to heat, depending on its vascularisation and microstructure. Numerous factors such as drilling pressure, number of revolutions, drill design, wear and material, drilling depth and cooling influence heat generation. Internally cooled drills are, therefore, increasingly used, even though the improved cooling effect compared to conventional externally cooled drills is controversial. Internally cooled drills may have the disadvantage of a germ reservoir developing in the cooling channel. This study aimed to examine the effects of disinfection and sterilisation of internally cooled drills. After contamination of the cooling channel with suitable bioindicators (Enterococcus faecium, ATCC 6057 and spores of Bacillus stearothermophilus, ATCC 7953), the drills were disinfected (disinfection solution ID 220, Dürr Dental) and autoclaved (Webeco, E5S90, 134 degrees C, 2.6 bar, 5 min). Disinfection was not completely effective except after pre-cleaning. By means of sterilisation all spores of Bacillus stearothermophilus were completely killed. Internally cooled drills can be successfully disinfected by means of this hygienic procedure routinely used in dental practice and no source of infection is created.

Pain during prophylaxis treatment elicited by two power-driven instruments

BACKGROUND

Sonic scalers have an elliptical and piezoceramic ultrasonic scalers a linear oscillation pattern. Thus, a sonic scaler "hammers" the tooth surface, irrespective of its alignment to the tooth, whereas a piezoceramic ultrasonic scaler may oscillate parallel to the tooth surface and gently remove calculus if the alignment is correct. The aim of this study was to measure pain on a visual analogue scale (VAS) during removal of supragingival calculus on mandibular incisors with a sonic or an ultrasonic scaler.

MATERIAL AND METHODS

Seventy-four periodontally healthy subjects with supragingival calculus on the mandibular incisors were treated with both a sonic and a piezoceramic ultrasonic scaler in a split-mouth design. The sequence of instrument application and allocation of instruments to jaw side were randomized. Patient comfort was assessed with a VAS after treatment.

RESULTS

The VAS results did not show any difference between the two instrumentation modalities.

CONCLUSION

For calculus removal during prophylaxis the type of power-driven instrument does not seem to have an impact on perceived pain. This means that the oscillation pattern does not influence the pain experience.

Do folic acid and thiocyanate have a preventive effect on exogenously induced disturbances of embryonic cranial development?

The preventive influence of folic acid and thiocyanate on procarbazine-induced disturbances of embryonic cranial development was investigated on experimental animals. Low dosages of folic acid or thiocyanate demonstrated no prophylactic effect. When thiocyanate was administered alone, an increased cleft rate was unexpectedly found for the secondary palate. The combined application of folic acid and thiocyanate showed a cleft-prophylactic effect in the secondary palate in addition to growth protection in the primary palate. It can be assumed that thiocyanate has a positive effect on chondral and osseous growth of the palate during the post-sensitive phase of embryogenesis, while in the sensitive phase, it can function as a carrier for teratogenous and toxic substances.

Sex-related differences in procarbazine-induced cleft palate and microgenia and the anti-teratogenic effect of prenatal folic acid supplementation in rats

Sex-related differences in the frequency of cleft palates and microgenia in rat fetuses prenatally treated with procarbazine (200 mg/kg on day 14 of gestation (GD14), group 1), and the anti-teratogenic effect of prenatal folic acid supplementation (4 mg/kg on GD14 through GD17, group 2) were studied in LEW.1A rats. In group 1, complete clefts were observed in 69% of the male and in 36% of the female fetuses while incomplete clefts (present only in the hard palate) were exhibited by 31% of the males and 43% of the females. Microgenia occurred in all males but only in 64% of the female fetuses. In group 2, the prenatal folic acid supplementation significantly reduced the occurrence frequency of complete clefts to 9% in males and to 0% in females. In contrast, incomplete clefts increased to 82% in males and 91% in females. Microgenias were reduced to 73% and 57% in male and female fetuses, respectively. Since incomplete clefts present in the hard palate are assumed to be residues of spontaneous intra-uterine repair processes of exogenously induced complete palatal clefts, we conclude that prenatal supplementation with folic acid at a dose of 4 mg/kg promotes the intra-uterine repair of cleft palates and offers a partial protection against procarbazine teratogenicity. Furthermore, it is deduced that gender-specific differences exist in the susceptibility to procarbazine and in the anti-teratogenic effect of folic acid on procarbazine-induced microgenia.

Formaldehyde inhalation & open field behaviour in rats

BACKGROUND & OBJECTIVES

It has been shown in animal studies that repeated exposure to formaldehyde vapour alters behaviour and memory. Since information is not available on the behavioural consequences of acute formaldehyde exposure, this study was conducted to investigate the influence of single inhalative exposure to formaldehyde on the explorative and locomotor behaviour of adult male and female rats.

METHODS

Rats were exposed to different concentrations of formaldehyde vapour (0.5, 1.0, 2.5%, corresponding to inhalation chamber concentrations of 1.0, 2.5, and 5.0 ppm, respectively) for 2 h and an open field test was carried out 2 h after the end of exposure (first test) and repeated 24 h thereafter (second test). The parameters examined were crossing of floor squares, sniffing, grooming, rearing, climbing, and defaecation.

RESULTS

In exposed male rats, significant reduction of crossed floor squares, grooming, and wall climbing, and increase in floor sniffing and rearing were observed in the first test. During the second test, males in the groups exposed to 2.5 ppm and 5 ppm crossed significantly higher numbers of squares when compared to controls. Air sniffing, wall climbing, and rearing were altered in all exposed males. Control males showed higher incidence of defaecation in comparison to the values of first test. The formaldehyde-exposed female rats crossed significantly decreased numbers of floor squares in the first test. In females in the 2.5 ppm and 5 ppm groups, decreased grooming and enhanced floor sniffing were observed. In the second test, all exposed females crossed higher numbers of floor squares than controls. Frequencies of air and floor sniffing were higher in females exposed to 2.5 ppm and lower in those exposed to 1 ppm. Defaecation was enhanced in females in the 2.5 ppm group in comparison to the first test.

INTERPRETATION & CONCLUSION

The results show that formaldehyde inhalation in the concentrations and duration of exposure used in the present experiments significantly influences the locomotor and explorative behaviour of rats after a single exposure in a gender-related manner and that various behavioural components in the exposed animals remains altered even after 24 h.

A study on the effect of inhalative formaldehyde exposure on water labyrinth test performance in rats

We investigated the effects of repeated inhalative exposure to several formaldehyde concentrations (2 hours/day, 10 consecutive days) on the behavior of adult male and female LEW.1K rats during a period in which they learned to perform a water labyrinth task. We also examined the effects on the histology of some organ tissues. While the controls needed increasingly shorter swimming periods to complete the water labyrinth test and made fewer errors with advancing trial duration, such progress could not be observed in the learning behavior of the exposed animals. They took significantly longer swimming periods to reach the finish and made significantly more errors in comparison to the controls. The statistical comparison between the collected data in the formaldehyde exposed male and female rats reveals that females in general reached the end point of the swimming labyrinth in significantly less time. On some trial days, however, they made more mistakes than males. In the highest concentration group, no gender differences were evident in the frequency of errors. The histological examination revealed no pathological changes attributable to formaldehyde exposure. Since the water labyrinth test is used to investigate changes in memory and learning behavior in animals, we conclude that under investigational conditions, formaldehyde affects the learning behavior and the memory of male and female rats.

Effects of prenatal procarbazine administration on intrauterine development in rats

The effects of prenatal procarbazine (PCZ) administration on the intrauterine development of rat fetuses were investigated. Gravid rats were treated on day 14 of gestation (GD14) with 25 mg or 50 mg/kg body weight PCZ via stomach tube. Controls received normal saline in the same dosis and manner. On GD20, all fetuses were collected by caesarian section. Live and dead fetuses as well as resorptions were counted. In the live fetuses, the following investigations were conducted: measurement of body weight, occipito-coccygeal-lenght (OCL), tail length (TL), placental weight and diameter, external macroscopic and binocular microscopic examination, and sectional analysis of the animals using the razorblade sectioning technique. Both PCZ doses caused a significant reduction in the number of live fetuses and a significant increase in resorptions. Mean body weight in PCZ groups was antidromic affected. OCL and TL were significantly depressed. Placental weight and diameter as well as number of dead fetuses were comparable to those of controls. External and sectional investigations revealed no PCZ-related deviations. In the light of our findings we conclude that PCZ in the doses used in this experimental study significantly affects the intrauterine development in rats in terms of fetal toxicity but displays no teratological properties.

[Is there new knowledge on embryology and functional anatomy of human mimetic muscles and the upper lip? A contribution to point selection, skin incision and muscle reconstruction in primary lip-nose reconstruction of uni- and bilateral lip-jaw-palatal clefts]

BACKGROUND

The great variety of primary cheiloplastic procedures in CLP patients shows that there is disagreement regarding the embryological development of this part of the face, the point selection, skin incision philosophy, and the macroscopic and microscopic functional anatomy of the human muscles of facial expression. We suppose from findings in Asian and African populations that the real embryological development of the upper lip differs from current textbook descriptions. Our own anatomical and embryological investigations serve as a basis for a critical discussion of different techniques of muscle reconstruction, point selection, and skin incision and for a description of an embryologically, functionally, and anatomically oriented operation technique for different entities of CLP.

METHODS

The findings of this study result from investigations of the embryonal and early fetal development from the 26th to the 112th i.u. day in REM pictures of the Anatomical Institute of the University of Göttingen (n = 8) and serial histological investigations of the Carnegie and Hooker-Humphrey Collections at the Armed Forces Institute of Pathology, Washington, D.C. (n = 40). Furthermore, we carried out microsurgical dissections of the muscles of facial expression, the osseous and cartilaginous parts of the nose, and the midfacial sutures in two adult heads without congenital disorders and one newborn head with a primary unilateral complete cleft of the lip and alveolus.

RESULTS AND DISCUSSION

The formation of the lower third of the upper lip is the result of contact of the maxillary bulges in the midline below the prolabium. According to this finding, the point selections and skin incisions have to be modified in the midline region in different types of uni- and bilateral CLP. Our technique of primary dissection, reorientation, and suturing of the muscles of facial expression is presented. The muscle reconstruction has to be performed independently from the skin preparation.

Is it possible to prevent cleft palate by prenatal administration of folic acid? An experimental study

OBJECTIVE

In this study, folic acid was tested for its antiteratogenic effects on experimentally induced cleft palate in animals.

DESIGN

Eleven pregnant Lew 1 A dams (75 fetuses) received 200 mg/kg procarbazine via gastric tubing on postconception (p.c.) day 14 to induce a cleft palate (CP); seven of the pregnant dams (45 fetuses) were additionally given 4 mg/kg folic acid subcutaneously from the 14th to the 17th day p.c. As a control group, three more pregnant dams (24 fetuses) were not treated with the drugs mentioned above. All fetuses were delivered by Caesarian section on day 20 p.c.

OUTCOMES MEASURED

All fetuses were weighed and examined macroscopically with a stereomicroscope. Each fetal head was cut into 35 frontal sections and scrutinized histologically.

RESULTS

None of the control fetuses (n = 24) exhibited a cleft. Without folate administration, 90% of the fetuses (27 of 30) that received procarbazine exhibited a CP. After additional prenatal folate administration, this rate remained virtually unchanged (91%; 41 of 45). However, the proportion of complete (total) CP (4%) was significantly (p <.0001) lower than in the group without folate (53%). Cleft-associated microgenia and microglossia were also significantly less frequent when folate was administered prenatally: microgenia was reduced by 22% (p =.029) and microglossia by 24% (p =.032).

CONCLUSIONS

On the basis of these results, folate has a partial ameliorating effect on the teratogenicity of procarbazine given to pregnant rats. Additional studies are necessary on the effect of folate in different species, also taking cleft lip and CP into consideration.

Functional improvement of the mandibular neuromuscular guidance by orthodontic-surgical treatment

The primary aim of the study was to reveal whether adult patients with skeletal mandibular retrognathism combined with a dental Class II relationship without craniomandibular pain show a characteristic pattern of free mandibular movements compared to patients with a Class I skeletal and dental morphology. The secondary aim was to investigate whether these characteristic structures are subject to change following combined orthodontic-surgical treatment. Free mandibular movements were measured with an ultrasound device and analyzed with computer software developed by the authors. In all patients examined, 2 maxillarily and mandibularly fixed axes were found. These axes have no direct relation to the temporomandibular joints, are positioned above and anterior to the joints and maintain a constant distance. This gear system is referred to as a neuromuscularly determined dimeric link chain. The position of the mandible is defined by the rotational angle mu and the inclination angle alpha around the axes of the dimeric link chain. This dimeric link chain of free movements of patients with Class I skeletal and dental relationship functions according to the principle of least action: The angular velocities around the 2 axes show a constant ratio within the different segments of motion, and in the mu-alpha diagrams the segments of mandibular movements are represented by straight lines, the shortest paths between 2 positions. Individual cases and statistical data show that the structure of mandibular movements of patients with skeletal mandibular retrognathism combines with a dental Class II relationship without craniomadibular pain differs significantly from that of patients with Class I alignment. Mandibular retrognathism and a Class II relationship are accompanied by marked coordination disturbances in the rotary movements around the maxillary and mandibular neuromuscular axes. Following orthodontic-surgical treatment to restore ideal alignment of the occlusal, articular, and skeletal structures, the patients showed a similar pattern in the structure of mandibular movements to that of patients with Class I sketal and dental relationships. Thus, combined orthodontic-surgical treatment leads to measurable functional hamonization not only of the skeletal and dental structures but also of the neuromuscular guidance system.

Substance loss caused by scaling with different sonic scaler inserts--an in vitro study

BACKGROUND, AIMS

Depending on the phase of periodontal treatment, power-driven inserts with different power levels are necessary: during initial treatment and flap operations, it must be possible to remove calculus which firmly adheres to the root surface with great efficiency; in contrast, gentle root-surface instrumentation has a high priority during maintenance treatment. Recently, modified sonic scaler inserts have been introduced: diamond-coated inserts for open flap operations and slim probe-shaped sonic scaler inserts for deplaqueing during maintenance.

METHOD

We compared the substance removal by these inserts to that of a conventional insert. In a bench system which allows application force, stroke height, and width and frequency of instrumentation to be monitored and also permits assessment of the topography before and after instrumentation (yielding depth removal and removed volume), we instrumented aluminum rods in triplicate and bovine roots in a 5-fold repetition.

RESULTS

With high application forces (1.0 N), the diamond-coated inserts removed 30 to 50% more substance than the conventional one. Except for the slim inserts, there was a significant linear relationship between increasing force and removed volume. Probe-shaped inserts do not remove considerable substance even with increasing pressures.

CONCLUSIONS

Diamond-coated inserts remove tooth substance very effectively and must thus be handled with care: more pressure effects more removal. Probe-shaped inserts can be used without risk during maintenance visits.

NMR solution structure of hPar14 reveals similarity to the peptidyl prolyl cis/trans isomerase domain of the mitotic regulator hPin1 but indicates a different functionality of the protein

The 131-amino acid residue parvulin-like human peptidyl-prolyl cis/trans isomerase (PPIase) hPar14 was shown to exhibit sequence similarity to the regulator enzyme for cell cycle transitions human hPin1, but specificity for catalyzing pSer(Thr)-Pro cis/trans isomerizations was lacking. To determine the solution structure of hPar14 the (1)H, (13)C, and (15)N chemical shifts of this protein have been assigned using heteronuclear two and three-dimensional NMR experiments on unlabeled and uniformly (15)N/(13)C-labeled recombinant protein isolated from Escherichia coli cells that overexpress the protein. The chemical shift assignments were used to interpret the NOE data, which resulted in a total of 1042 NOE restraints. The NOE restraints were used along with 71 dihedral angle restraints and 38 hydrogen bonding restraints to produce 50 low-energy structures. The hPar14 folds into a betaalpha(3)betaalphabeta(2) structure, and contains an unstructured 35-amino acid basic tail N-terminal to the catalytic core that replaces the WW domain of hPin1 homologs. The three-dimensional structures of hPar14 and the PPIase domain of human hPin1 reveal a high degree of conservation. The root-mean-square deviations of the mean atomic coordinates of the heavy atoms of the backbone between residues 38 to 45, 50 to 58, 64 to 70, 81 to 86, 115 to 119 and 122 to 128 of hPar14 were 0.81(+/-0.07) A. The hPar14 model structure provides insight into how this class of PPIases may select preferential secondary catalytic sites, and also allows identification of a putative DNA-binding motif in parvulin-like PPIases.

Polymorphism of the N-acetyltransferase (NAT2), smoking and the potential risk of periodontal disease

Periodontal disease is a common multifactorial process that leads to bone destruction and tooth loss. Interactions of environmental and genetic factors determine the extent and severity of periodontal disease. Smoking is one of the risk factors for periodontal disease, and the risk may be influenced by the polymorphism of N-acetyltransferase (NAT2) via metabolism of smoke-derived xenobiotics. We therefore hypothesized that a NAT2 genotype would be a risk factor for periodontal disease. A total of 154 Caucasian subjects were assigned to one of two groups (1) no or mild and (2) severe periodontal disease based on radiographic (bone destruction) and clinical criteria (probing depth, attachment loss) and the number of teeth. In all subjects genotyping for mutations on NAT2 was performed by means of PCR and RFLP analysis. In the less-affected group genotyping showed a fraction of predicted slow and rapid acetylators (53.6% and 46.4%, respectively) corresponding to the normal distribution in Caucasians. Severely affected patients were predominantly slow acetylators, the odds ratios being between 2.38 and 5.02 for the NAT2-related risk depending on the outcome parameters chosen. Adjustment for age had no influence on these findings. Our data indicate that the slow acetylator phenotype is associated with a higher risk of periodontitis, especially with respect to the severity of the disease. Possible implications with respect to the risk associated with smoking are discussed.

Bending vibrations of the femur and the oscillatory behavior of a cemented femoral hip endoprosthesis

The paper presents a novel method for recording amplitude and phase of 6D-vibrations of a spatial pendulum over a wide frequency range (10 Hz up to 20 kHz). The six degrees of freedom of the pendulum mass were monitored by three electrodynamic stereo pickups. At rest, the tips of the needles and the pendulum's center of mass defined the reference system with respect to which the oscillations of the mass were recorded in terms of their amplitudes and phases. Its small dimensions, constant transfer characteristics, linearity, high dynamics, and virtual lack of reaction onto the moving system over the entire frequency range provided the advantages of the measuring system. This method was used to analyze the spatial 6D-vibrations of the head of a cemented femoral hip endoprosthesis when the femur was stimulated to bending vibrations. The head of the prosthesis carried out axial rotational vibrations at every frequency used to stimulate the femur. The amplitudes of the axial rotations of the cortical bone were small in comparison to the ones of the prosthesis head, indicating that axial rotational vibrations following femur bending vibrations mainly stressed the spongiosa and the cement layer. This was observed over the entire frequency range, including at the low frequencies relevant for gait. Over the low-frequency range, as well as at some of the higher resonance frequencies, stationary instantaneous helical axes characterized the vibrations. The measurements suggest the mechanism that the interface "implant-bone" may already be stressed by axial torsional loads when the femur is loaded by bending impacts that are known to occur during walking.

A case of a persistent left vena cava superior with atresia of the right atrial ostium of the coronary sinus

A persistent left vena cava superior with an atretic ostium of the coronary sinus was found during the routine dissecting course in the embalmed cadaver of an 83-year-old woman who had died from cardiac infarction. The left vena cava superior was very narrow in diameter (4 mm), originated at the lateral part of the left vena brachiocephalica and ran down between the venae pulmonales sinistrae and the auricula sinistra. The vena cava opened into the sinus coronarius of the heart, which terminated as a blind sac due to an atretic ostium. The vena coronaria sinistra as well as the vena interventricularis posterior drained into the sinus coronarius. Congenital atresia of the coronary opening is a rare malformation and is usually associated with other anomalies. The congenital ostial atresia could be the cause of a persistent left vena cava superior, which then takes over the drainage of the cardiac veins.

Disturbances of palatogenesis and their prophylaxis in animal experiments

The goal of this study using experimental animals was to induce disturbances of palatogenesis which are comparable to human maxillary clefts. Simultaneously, an in vivo method of testing presumed antiteratogenic substances is presented. 13 gravid Wistar rats bearing 98 fetuses received 200 mg/kg of procarbazine on day 14 post conception (p. c.) to induce malformations. 7 of these gravid animals, bearing 48 fetuses, additionally received 200 mg/kg thiamine daily from day 13-19 p. c. to prevent malformations. On day 20 p. c., the fetuses were teratologically screened: all fetuses were externally examined, the skeletons of 1/3 were visualized using cartilage/bone staining methods, and the heads of 2/3 were histologically examined in 24 sequential frontal sections. At birth, the procarbazine-damaged fetuses exhibited a high rate of cleft palate, primarily involving the secondary palate (94%), which was accompanied by retardation and delayed ossification of the viscerocranium. 66% of the fetuses showed pronounced brachygenia. The disturbances of palatogenesis were frequently accompanied by disturbed odontogenesis, which chiefly manifested itself near the cleft of the frontal maxilla as a reduction in size (63%), retardation (38%) or absence (31%) of the tooth germ. In the trial group additionally treated with thiamine, the findings did not differ significantly from these. The animal model presented here proved suitable for studying palatogenesis and localization-specific testing of substances presumed to have antiteratogenic effects. A prophylactic effect of thiamine initially tested as a highly-dosed monotherapy was not verifiable.

Masticatory musculature under altered occlusal relationships--a model study with experimental animals

In a study with experimental animals, the occlusal relationships of male Wistar rats were altered by the bilateral extraction of lateral teeth; the bolus function was eliminated by feeding a soft diet. Both steps led to relief of strain on the temporomandibular joint and thus also in the muscular system itself. The masticatory muscles adapted to the new experimental conditions. We observed a reduction in muscle dry weight and a shift in muscle fiber composition in favour of the IIb fibers, which indicates that less masticatory strength was required. Adaptation thus occurred equally on the macroscopic and microscopic levels.

Interpretation of the vertical and longitudinal growth of the human skull

Our model describes asymptotic growth as a time-dependent process which expresses a quantitative change in individual morphological factors. The development and growth of the face are intimately connected with the cranial base, which undergoes only minor changes between the ages of 0 to 25 years. The difference in growth of the neuro- and viscerocranium is evident in that the dimensions and angles of the viscerocranium undergo greater changes than those of the neurocranium. The anterior cranial base lengthens until the end of normal growth via bone apposition at the nasion. This elongates the cranial base. The nasion influences the sagittal maxillary relationships. The posterior cranial base shows a constant growth rate up to ca. 15 years of age. The face and dentition develop along the nasion-gonion and sella-gnathion distance, which demonstrates the greatest absolute growth rate. During growth, the viscerocranium increases principally in height.

Alteration of the functional condition of the mandible during clinical treatment

Free mandibular movements and their neuromuscular guidance were measured with an ultrasonic device and analyzed with computer software developed by the authors. In all patients examined, we found maxillarly- and mandibularly-fixed axes which maintain a constant distance. This guidance system is named a neuromuscularly-determined dimeric link chain. The position of the mandible is defined by the 2 rotational angles (mu, alpha) around the axes of the dimeric link chain. This dimeric link chain of free movements normally functions according to the principle of least action. The angular velocities around the 2 axes show a constant ratio during the different segments of motion. In the mu-alpha-diagrams, the segments of movements of the mandible are represented by straight lines, the shortest path between 2 positions. Individual cases and statistical data show that the structure of mandibular movements of patients with skeletal mandibular retrognathism combined with dental class-II-relationship without craniomandibular pain significantly differs from the structure in patients with neutral alignment. Mandibular retrognathism and class-II-relationship are accompanied by marked coordination disturbances of rotations around the maxillary and mandibular neuromuscular axes. Following orthodontic-surgical treatment that restored ideal alignment of the occlusal, articular, and skeletal structures, the patients examined showed a similar pattern in the structure of mandibular movements to that of patients with neutral skeletal and dental relationships. Thus, combined orthodontic-surgical treatment leads to measurable functional harmonization not only of the skeletal and dental structures, but also of the neuromuscular guidance system.

The influence of the muscles of facial expression on the development of the midface and the nose in cleft lip and palate patients. A reflection of functional anatomy, facial esthetics and physiology of the nose

The further improvement of well-established techniques in primary and secondary cleft surgery requires a detailed and interdisciplinary knowledge and observation of anatomical, functional and developmental problems. An investigation into the macroscopic and microscopic anatomy of the perinasal and perioral muscles and parts of the human nasal septum, as well as into the pathomorphology of ancient skulls with untreated clefts is presented. On this basis an interpretation of clinical findings in untreated newborns compared with surgically treated CLP-patients has been undertaken. The 3D-CT, superimposing photography and coloured experimental settings of nasal airflow complete the visualisation of the anatomical and functional findings.

Functional conditions of the mandible: theory and physiology

The functional conditions of the mandible are differentiated according to the number of kinematic degrees of freedom assigned to each mandibular movement. One degree of freedom: pro- and retrusive occlusal border movement. The interplay of the TMJs with the occluding teeth determines a compulsory course which corresponds to a 4-bar-chain guidance. 2 degrees of freedom: free sagittal mouth movement without tooth contact. Using graphic recordings of cyclic mandibular movements, the mobile hinge axis is identified as a mandibularly fixed line which is not directly categorized as a part of an anatomical structure. In the maxillary coordinate system, its movement describes a cylinder; sagittally, it describes a circle. The mandibular positions are clearly identifiable with 2 angles. The in vivo measurements show that neuromuscularly healthy systems supply the mandible with anticipatory guidance. 3 degrees of freedom: bolus function. The articular space in the TMJ is utilized.

Cheilognathopalatoschisis and its prophylaxis in animal experiments

Cheilognathopalatoschisis (cleft lip, -maxilla, and -palate) is the second most frequent malformation in humans. The ontogenetic causes are mostly multifactorial. Some researchers have succeeded in lowering the frequency of occurrence of such clefts in children of predisposed women by giving the latter an applied symptomatic replacement therapy with multivitamin preparations or other substance classes during early pregnancy. However, the dosage of these substances was only anecdotal and their effect unspecific. Many research groups world-wide are conducting animal experiments in order to investigate the efficacy of vitamins and other substances as prophylactics. The experiments are usually conducted with laboratory rats and mice, and clefts are often induced by applying chemical noxa. The results of these trials, however, are controversial. Where some authors were able to prove protective effects of the vitamins or other substances they employed, others found evidence that such replacement therapy has no prophylactic effect. This paper provides insight into such studies with experimental animals, and compares their results.

Functional condition of the mandible: physical structures of free mandibular movement

Starting with the physical definition of the concept "mobile hinge axis", which only allows 2 degrees of freedom for planar mandibular movement, it will be shown that the hinge axis of the temporomandibular joint cannot be found with a small mouth-opening rotation, as is usual but erroneous. By recording cyclic mandibular movements with a measuring system which itself possesses 6 degrees of freedom, the mobile hinge axis can be found. However, there are patients which do not use a mobile hinge axis, which is indicative of latent functional disturbances of the neuromuscular system.

Application of thiamine in preventing malformations, specifically cleft alveolus and palate, during the intrauterine development of rats

OBJECTIVE

Animal experiments were conducted to test the reproducibility of previously documented antiteratogenic effects of thiamine on cleft formation in the craniofacial system.

DESIGN

Thirteen gravid Wistar rats carrying 98 fetuses were given the hydrazine derivative procarbacine (200 mg/kg BW) on the fourteenth day postconception (PC) to induce malformations, chiefly cleft alveolus and palate (day of determining presence of sperm was called the first day PC). Seven of the treated gravid rats carrying 48 fetuses were additionally given a daily dose of 200 mg/kg thiamine from the thirteenth to the nineteenth day PC.

OUTCOME MEASURES

A comparative analysis of the fetuses in both experimental groups was conducted externally and, for the skeleton, macroscopically using special staining techniques; the heads were analyzed using successional histologic sections; bodies were examined stereomicroscopically using the razor-blade sectioning technique.

RESULTS

In 12 of the 16 parameters evaluated, no statistically significant differences were found between experimental groups. In some cases, we even observed an amplifying effect of thiamine on the development of malformations in the rat strain used in our study.

CONCLUSIONS

Because several previous authors have repeatedly described treatment with thiamine as one of the sufficient prophylactic measures in slowing the development of viscerocranial malformations, especially cleft alveolus and palate, it is of utmost importance that the timing of treatment and dosage of thiamine be taken into consideration not only in animal experiments but also when applying results to humans.

Cultured gastric parietal cells from the guinea pig: adherence, cell growth and stimulus coupling of Ca2+ and cyclic AMP

The aim of the study was to establish cell culture conditions for responsive guinea pig parietal cells. Parietal cells were isolated by a pronase/collagenase method, enriched by counterflow elutriation and cultured on plastic culture dishes in minimum essential medium. Precoating with gelatine or collagen increased adherence; optimum fetal calf serum concentration was 10%. Parietal cells were cultured for up to 120 h. Intracellular calcium levels in cells cultured for 48 h were 150 nmol/l and increased to 320 nmol/l after stimulation with carbachol and to 250 nmol/l after histamine stimulation as determined by video imaging microscopy. Intracellular cyclic AMP levels were increased 9-fold by histamine in cells cultured for 24 h and more than 30-fold in cells cultured for 48 h. The results show that guinea pig parietal cells grow in primary culture and are suitable for studying second messenger coupling.

[Measuring spatial micro-movement of the femur shaft of endoprostheses in relation to the spatial force system]

A precision measurement method (resolution: 0.1 micron) is described that simultaneously tracks spatial movement of the prosthesis and its bending as a function of the spatial force system (three force and three torque components). With this technique, we examined the effects of complete separation between shaft and cement on bending and micromovement. With regard to mechanical stability a completely tied and a loosened prosthesis differ only in respect to torsional load: the loosened prosthesis bears a 2.5-fold larger torsion flexibility. In both cases the shaft does not move like a rigid body: it bends up or down depending on the way the torque acts. It is the torques (that are produced by the forces) rather than the forces themselves that are responsible for the extent of micromovement and bending. In the completely loosened shaft, the shaft's apex only moves either intrusively or extrusively according to the directions of the torque vector: the horizontal movement cannot be resolved. The data suggest that shafts that are freely mounted into its cement quiver load the cement layer in a less damaging fashion than tied shafts.

Suitability of different staining methods for the identification of isolated and cultured cells from guinea pig (Cavia aperea porcellus) stomach

Cell suspensions from the guinea pig gastric mucosa were obtained using a pronase/collagenase isolation method, and cultured on Petri dishes in minimum essential medium at 37 degrees C. For proper identification of different gastric cell types in cytospots, cell suspensions or culture, selective staining methods were employed, modified and evaluated. Mucous cells and mucous neck cells were detected by use of lectins. Mucous cells were stained on cytospots and in primary cultures with lectins from peanut, Helix pomatia, Ulex europaeus, wheat germ, and from soybean. Vital chief cells in suspensions but not in culture, were selectively stained by Nile blue sulphate, brilliant cresyl blue or the fluorescence dye dihexyloxacarbocyanine iodide. Pepsinogen granules of isolated and cultured chief cells were detected with a polyclonal antibody against porcine pepsinogen. Isolated parietal cells were identified in cytospots by using acidophilic dyes (aurantia, eosin). In suspensions and in cultures vital parietal cells were identified by enzymatic detection of succinic dehydrogenase or carboanhydrase activity and by the vital stain Janus green. In cultures exclusively, parietal cells were additionally identified by the vital stain rhodamine. Cytochemically, they were identified with phalloidin by binding to actin filaments. Endocrine cells in the suspension were visualised immunocytochemically with antibodies directed against different amines or peptides. Fibroblasts and endothelial cells were identified after isolation and in primary culture with a vimentin antibody. Mast cells in suspension were either visualised by a histamine antibody or by metachromatic staining behaviour to toluidine blue, respectively. Endothelial cells in suspension or culture were distinguished from fibroblasts by endocytosis of acetylated low-density-lipoprotein. In conclusion, the developed methods are highly suitable to identify guinea pig gastric cells after isolation and follow up their fate in primary culture.