Anaplasma Species in Ticks Infesting Mammals of Sardinia, Italy

Ticks are hematophagous ectoparasites that are recognized for their ability to vector a wide variety of pathogens of viral, bacterial, protozoal, and helminthic nature to vertebrate hosts. Among the different diseases transmitted by ticks, also called "Tick-Borne Diseases" (TBD), many are zoonotic. Pathogens of the genus Anaplasma refer to obligate intracellular bacteria within the Rickettsiales order transmitted mainly through tick bites and considered as well-established threats to domestic animals, livestock, and humans, worldwide. In this retrospective study, 156 ticks collected from twenty goats, one marten, and one cattle from several Sardinian sites, were examined by molecular analyses to detect the presence of Anaplasma species. A total of 10 (10/156; 6.4%) ticks were shown to be Anaplasma-positive by PCR screening. After sequence analyses, A. phagocytophilum was detected in four Rhipicephalus sanguineus s.l. (3.3%) and four Rh. bursa (11%) ticks from goats, while one Rh. sanguineus s.l. (0.8%) and one Rh. bursa (2.8%) collected from the marten and cattle, respectively, exhibited 100% of identity with A. marginale strains. In this study, we provide the first description and molecular detection of A. marginale and A. phagocytophilum in ticks of the Rhiphicephalus genus in Sardinia. Considering the growing impact of tick-borne Anaplasma pathogens on human health, further studies are necessary to monitor the prevalence of these pathogens in Sardinia.

Molecular Investigation of Theileria and Babesia Species in Domestic Mammals from Sardinia, Italy

Piroplasmoses are tick-borne diseases caused by hemoprotozoan parasites of veterinary and public health significance. This study focuses on the molecular identification and characterization of species belonging to the Theileria/Babesia genera in 152 blood samples, collected from 80 horses and 72 cattle from several farms in Sardinia, by targeting the 18S rRNA gene. The PCR results highlighted that 72% of the samples were positive for Theileria/Babesia spp., with a rate of infection of 68% and 75% for the horses and cattle, respectively. Sequencing and the BLASTn analysis showed that the 18S rRNA generated in this study has 99-100% homology with the B. bigemina, T. orientalis/sergenti/buffeli, T. equi and T. annulata strains isolated from different hosts worldwide. These findings improve the knowledge on Babesia and Theileria infections in domestic mammals and confirm the significant prevalence of piroplasmosis among subclinical and carrier animals throughout the island. Furthermore, the presence of T. annulata, reported for the first time in the study area, expands the repertoire of pathogens already detected in Sardinia. Our results gather updates on the diversity and distribution of piroplasms in Sardinia and suggest the need to develop procedures to improve animal and public health safety.

Molecular detection of Theileria sergentii/orientalis/buffeli and Ehrlichia canis from aborted ovine and caprine products in Sardinia, Italy

The economic impact and losses caused by abortion of small ruminants represent an important threat to livestock industry worldwide. Infectious agents are the most commonly causes of small ruminant abortion and many of which pose a serious threat to human health. The management of abortion outbreaks is essential to understand the transmission, prevention and control of the zoonotic diseases. This study aimed to increase the knowledge about the common known zoonotic pathogens causing abortion (Coxiella burnetii, Chlamydia abortus and Toxoplasma gondii) circulating in Sardinia. In addition, the occurrence of other infectious agents that, until now, had never been identified in abortion samples and which might be cocirculating during the abortion outbreaks were also considered. In this study, 125 abortion samples collected from 91 small ruminant farms were screened for the presence of Babesia/Theileria spp., Ehrlichia canis, Anaplasma spp., Chlamydia spp., C. burnetii and T. gondii by PCR analyses and sequencing. This is the first evidence on the presence of Theileria sergenti/orientalis/buffeli group and Eh. canis in 22 (22/125; 18%) and 26 (26/125; 21%) abortion products from small ruminants, respectively. Chlamydia abortus, C. burnetii and T. gondii were also detected in brain, liver, spleen and placentae at 46% (58/125), 34% (42/125) and 2% (2/125), respectively. This study highlights that pathogens with epizootic and zoonotic potential are circulating in the island and could be involved directly or in association with other pathogens as possible cause of ruminant abortion. Further studies are needed to fully assess the impact of Theileria sergenti/orientalis/buffeli group and Eh. canis on ruminant abortion and their real zoonotic risk in the island.

Coexistence of Tick-Borne Pathogens in Ticks Collected from their Hosts in Sardinia: an Update

PURPOSE

In recent decades, the incidence and distribution of tick-borne diseases have increased worldwide, attracting the attention of both clinicians and veterinarians. In Sardinia, notifiable tick-borne diseases are spreading and Mediterranean spotted fever (MSF) rickettsiosis continues to be endemic with an incidence of 10/10,000 inhabitants per year. Furthermore, ticks can transfer more than one pathogen after a single blood meal from a coinfected host or after multiple feeding on different infected hosts. The aim of this study was to update information on ticks and tick-borne diseases, focusing also on the presence of coinfection in Sardinian ticks.

METHODS

The presence of protozoan (Theileria and Babesia species) and bacterial pathogens (Rickettsia spp., Anaplasma spp., Ehrlichia canis, Chlamydia spp., Bartonella spp., and Coxiella burnetii) was evaluated in 230 ticks collected from different hosts in Sardinia.

RESULTS

PCR and sequencing analyses highlighted that the 59% of ticks were infected with at least one pathogen while the 15% resulted in coinfection by double and triple pathogens. Among the double co-infections, those of E. canis/C. burnetii, Babesia sp. Anglona/Ch. psittaci and Babesia sp. Anglona/C. burnetii revealed a statistically significant index of coinfection.

CONCLUSION

This study identifies new pathogens in Sardinian ticks and updates the information about tick-borne diseases in the island. We also provide new results on the presence of coinfections in collected ticks. The knowledge about the diversity of ticks and tick-borne diseases circulating in Sardinia is a necessary step toward implementing effective tick-borne disease prevention and control programs.

Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Aflatoxin B1 in Corn Samples: Interlaboratory Study

An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 levels in corn samples, enforced by European Union legislation. A test portion was extracted with methanolwater (80 + 20); the extract was filtered, diluted with phosphate-buffered saline solution, filtered on a microfiber glass filter, and applied to an immunoaffinity column. The column was washed with deionized water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase LC with fluorescence detection after either pre- or postcolumn derivatization. Precolumn derivatization was achieved by generating the trifluoroacetic acid derivative, used by 8 laboratories. The postcolumn derivatization was achieved either with pyridinium hydrobromide perbromide, used by 16 laboratories, or with an electrochemical cell by the addition of bromide to the mobile phase, used by 5 laboratories. The derivatization techniques used were not significantly different when compared by the Student's t-test; the method was statistically evaluated for all the laboratories. Five corn sample materials, both spiked and naturally contaminated, were sent to 29 laboratories (22 Italian and 7 European). Test portions were spiked with aflatoxin B1 at levels of 2.00 and 5.00 ng/g. The mean values for recovery were 82% for the low level and 84% for the high contamination level. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally contaminated samples (blind pairs at 3 levels), the values for relative standard deviation for repeatability (RSDr) ranged from 9.9 to 28.7%. The values for relative standard deviation for reproducibility (RSDR) ranged from 18.6 to 36.8%. The method demonstrated acceptable within- and between-laboratory precision for this matrix, as evidenced by the HorRat values.

Molecular characterization of Toxoplasma gondii Type II in sheep abortion in Sardinia, Italy

During 2009–2010, 161 tissue samples (142 placentas, 16 brains, and 3 livers) from aborted ovine fetuses on Sardinia Island, Italy, were tested for toxoplasmosis. Organs that showed a positive result by nested polymerase chain reaction (PCR) targeting the ITS1 region for Toxoplasma gondii were also amplified with 11 genetic markers (SAG1, 5′-SAG2, 3′-SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) and then subjected to PCR/RFLP for genetic typing. T. gondii DNA was found in 5 placentas, 14 brains, and 2 livers by PCR analysis and all isolates displayed Type II alleles at all 11 loci with all 11 markers. The results indicate that the Type II T. gondii is associated with ovine abortion.

Influence of posture on swallowing

AIM

This study investigates the relationship between posture disorders and swallowing, either of infantile type or affected by the presence of a short lingual frenulum.

MATERIALS AND METHODS

The stabilometry examinations, taking into account the Romberg index and the LFS value, and when needed a frenectomy, showed positive variations in the recovery of a proper posture. The data were analysed by means of the Wilcoxon signed-rank test.

RESULTS AND CONCLUSION

This study showed that swallowing is able to modulate postural control and it can be a determining factor in postural syndromes that, if not promptly intercepted, may evolve into full-blown and irreversible musculoskeletal disorders for which treatment often proves ineffective.

Low cadmium concentration in whole blood from residents of northern Sardinia (Italy) with special reference to smoking habits

INTRODUCTION

The present study was initiated to investigate the cadmium concentrations in whole blood of Northern Sardinian, non-occupationally exposed adult subjects. Sardinia is a large Italian island which differs genetically and environmentally from other mainland Italian areas.

METHODS

Two hundred and forty-three adults (157 females and 86 males) were selected in the study area from subjects who were undergoing blood collection for laboratory analysis during the period January 2005-May 2005. Whole blood was analysed by graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background corrector (Perkin Elmer ZLS5100) and an auto sampler. The adopted analytical procedure uses the Stabilized Platform Temperature Furnace (STPF) technique.

RESULTS

The mean value of Blood Cadmium Concentration (BCdC), expressed as Geometric Mean, was 0.32 pg/l (CI 95%: 0.31-0.34 l) in non-smokers to 034 pg/l (CI 95%: 0.30-0.39 pg/l) in ex-smokers up to 0.47 gg/ll(CI 95%: 0.42-0.53 pg/l) in smokers (p < 0.0001).

DISCUSSION

The results show that BCdC levels in Northern Sardinian non-occupationally exposed adults are lower than levels found in many other regions, including those within Italy. Nevertheless, similar values have been detected in other European countries and cities.

CONCLUSIONS

In relation to other reports in which data were analysed by strata for smoking habit and age, we found similar BCdC values among non smokers. However, Sardinian smokers seem to show lower levels of blood cadmium.

Ages of eruption: study on a sample of 204 Italian children aged 6 to 24 months

AIM

The purpose of this study is the evaluation of the tooth eruption ages in a sample of children aged between 6 and 24 months.

MATERIALS AND METHODS

The sample consists of 204 children aged between six and twenty-four months, followed up for a period of one year in collaboration with seven pediatricians in the province of Sassari (Italy). The visits were carried out at the paediatricians' practice in order to receive immediate feedback about the clinical conditions of children.

RESULTS

Regarding the ages of eruption of all elements it was observed a shift more or less important, depending on the tooth considered.

Carboplatin Sustained Delivery System Using Injectable Microspheres

A controlled carboplatin delivery system using biodegradable polymer has been used in this study. The purpose was to evaluate the local and systemic effects of injectable, biodegradable microspheres containing carboplatin when injected as aqueous suspension subcutaneously in rats. Biocompatibility and toxicity of empty microspheres and microspheres loaded with carboplatin were evaluated by clinical and histological examination. The diffusion of carboplatin in tissues and time of drug release were evaluated by platinum determination in plasma and tissues over the time. The results of the study suggest that microspheres provide a sustained slow release of carboplatin and that multiple inoculations of microspheres containing drug and no evidence of local or systemic toxicity is found. This device may be useful in the treatment of solid tumours.

Occurrence, distribution, and role in abortion of Coxiella burnetii in sheep and goats in Sardinia, Italy

Between 1999 and 2002, 9349 sera and 517 aborted samples (422 foetuses and 95 placenta) were analysed from 675 sheep and 82 goat farms distributed all over the island of Sardinia. After abortion notification, sera collected at random from adult animals were examined to detect antibodies specific to Coxiella burnetii by ELISA, whereas foetuses and placenta were analysed by PCR assay. Specific IgG antibodies were detected in 255 (38%) sheep farms and in 39 (47%) goat herds whereas 40 ovine (10%) and 3 (6%) caprine foetuses were C. burnetii PCR-positive. Although C. burnetii DNA was amplified from different types of tissues, placenta was the tissue with the highest detection rate. Seroprevalence analysis indicates that C. burnetii distribution in sheep and goats is very high, but PCR results demonstrate that C. burnetii has a relatively low role in abortion, especially in goats.

[The influence of occlusion on sporting performance]

AIM

The purpose of the present study is to investigate the relationship between dental occlusion and physical performance using the Ergo-jump platform, and to highlight connections, if any.

METHODS

For the purpose of this research, 30 patients suffering from cervico-facial pathology and 10 without temporomandibular joint dysfunction were selected from within the Dental Clinic of the University of Sassari. For the first group a resin plate was prepared to correct the malocclusion, while for the control group a bite was prepared that created it. Subjects carried out exercises with the Ergo-jump platform, a device that assesses physical capabilities and athletic performance. Patients were asked to do 2 exercises, a counter movement jump and a mechanical power test, with plate and without plate.

RESULTS

The tests of the first group were as follows: flying times with the bite were 0.01 s longer; the average elevation in the counter movement jump test did not give statistically significant results; execution of the mechanical power test suggests an increase in average mechanical power with the plate. Execution of the same exercises in the other group showed greater flight times without the place; average elevation was not statistically significant; the execution of the mechanical power test showed a decrease in average mechanical power with the occlusion plate.

CONCLUSION

Statistical analysis of individual results showed that patients do not always obtain a benefit during physical exercise using the bite. Research shows that the same pathology can cause different physical performance in different individuals; in fact, not all craniomandibular disturbances have repercussions on posture.

[Morphologic evaluation of adhesive/resin cement system and fiber post: a sem investigation]

AIM

The purpose of the present paper is to carry out an SEM investigation into the adhesive cementation of quartz fibre posts in canals treated with endodontic cements containing or not containing eugenol.

METHODS

Sixteen selected tooth roots were subdivided into 4 groups and prepared with the step-back technique. Group A, without canal filling and with a cemented post, was the control group; in groups B and C, the canals were closed with guttapercha, endomethasone C and eugenol, those of group D with guttapercha and AH Plus without eugenol. The canals were prepared so as to be able to take D.T. light-posts irrigated with water (group C with ethyl alcohol) mordanted with orthophosphoric acid after applying 2 layers of photopolymerised ONE-STEP; 2 layers of ONE-STEP were applied to the post. DUO-LINK cement was positioned in the canal after inserting the post, removing excess resin and photopolymerising. The samples were prepared for SEM observation.

RESULTS

Group A: the apical portion shows the post absorbed into the cement and resin tags; group B: porosity is noted between cement and post, the hybrid layer does not present tissue penetration of the dentin resin; group C: bullae can be seen between cement and post surface and between hybrid layer and cement; group D: there is relative continuity between post surface, cementing resin, hybrid layer and underlying dentin.

CONCLUSION

The study has shown that eugenol interferes with the formation of the hybrid layer, the pictures relative to the resinous cement appeared different depending on whether the canal was treated with cement containing or not containing eugenol.

[Stabilimetry and cranio-cervico-mandibular disorders]

BACKGROUND

Cranio-cervico-mandibular disorders can cause disturbances in posture. Stabilimetry measures spatio-temporal variations in the center of body pressure and evaluates the mechanisms of maintenance of balance. The study used a stabilimetric platform to evaluate posture changes in patients with cranio-cervico-mandibular disorders before and after treatment for malocclusion.

METHODS

Between February 1998 and December 2000, 60 patients with cranio-cervico-mandibular disorders were recruited from the Dentistry Clinic of the University of Sassari. Each patient underwent two stabilimetric examinations (closed mouth with cotton wads inserted between the dental arches). The tests were conducted on a stabilimetric platform. Measurement of body posture load and sway were analyzed with a specific software program that correlated the vestibular, somatosensory and visual systems, and determined the role of each in postural control.

RESULTS

The stabilimetric analysis showed that the adoption of the plaque allowed rebalance of the postural system, without affecting the visual system. After treatment, 64% of patients experienced remission of pain symptoms with orthotic therapy.

CONCLUSIONS

The relationship between malocclusion and posture should be seen from a holistic standpoint in other to gain a global therapeutic outcome.

[In vivo evaluation of carbon fiber posts]

BACKGROUND

The use of carbon fiber posts allows morpho-functional restoration of endodontically treated teeth with an assembly of materials of a modulus of elasticity similar to that of dentin. The study clinically evaluated the percentage of survival of dental elements treated and reconstructed with endocanal carbon fiber posts.

METHODS

At the Dentistry Clinic of the University of Sassari 60 dental elements were selected from 46 subjects. The teeth, which had been treated endodontically with success for at least six months, were classified by parameters taken from the international literature and reconstructed using Tech 2000 carbon fiber posts and adhesive resinous systems recommended by the post manufacturer.

RESULTS

The success rate was 98.4%. Almost half (49%) of the samples were single-rooted elements, 37.4% of the posts were 1.2 mm in diameter; in 78.3% the opposing contact was with a natural tooth; 100% of the elements had a type A dental structure.

CONCLUSIONS

Third generation posts are a valid alternative to metallic posts and improve the prognosis of the treated element. The carbon fiber posts fixed with the composite, forming a single unit with the dental element, thus improving mid-term RESULTS. The technique is easy to use under clinical conditions and can be performed in a single session. So far, the method has provided promising clinical results, as this study demonstrated.

Sequence, cloning, expression and characterisation of the 81-kDa surface membrane protein (P80) of Mycoplasma agalactiae

Mycoplasma agalactiae, the causative agent of contagious agalactia in small ruminants, produces a protein, named P80, that is detectable in all wild-type isolates examined to date and that appears expressed during the early phase of infection. We describe here the identification, cloning and expression of the gene encoding P80 (ma-mp81). The deduced amino acid sequence is consistent with a hydrophobic and basic protein that possesses a lipoprotein signal peptide. Sequence analysis of gene ma-mp81 suggests that P80 is a membrane lipoprotein that shows significant homology with other putative lipoproteins of M. pneumoniae. An internal 1-kb fragment of ma-mp81 was expressed in Escherichia coli as a 6xHis-tagged protein. The purified recombinant protein greatly reacted with polyclonal anti-P80 sera raised in lamb.

Jaw muscle response to stimulation of type II somatosensory afferents of limbs in the rat

Convergence of various afferent inputs onto brainstem neurones may play an important role in the regulation of trigeminal motor activity. In particular, previous studies suggest that, besides sensory inputs arising from the orofacial region, extratrigeminal information may modulate jaw muscle function. In the present study the actions exerted on masseter and digastric muscles by the activation of somatosensory afferents coming from fore- and hind limbs were examined. The electromyographic activity (EMG) of masseter and digastric muscles was recorded in 20 anaesthetised rats, and EMG responses to single and paired electrical stimulation of common radial and sciatic nerves, at a threshold intensity for the activation of group II afferent fibres, were studied. The stimulation induced an excitatory response in both masseter and digastric muscles bilaterally. Ipsiand contralateral radial nerve stimulation evoked masseter responses at latencies of 13.8 +/- 2.4 ms and of 18.0 +/- 2.6 ms, respectively, and digastric responses 1.6 +/- 0.4 ms later. Ipsi- and contralateral sciatic nerve stimulation elicited masseter responses at latencies of 21.4 +/- 2.6 ms and of 23.3 +/- 2.0 ms, respectively, and digastric responses 2.0 +/- 0.2 ms later. The same masseter and digastric motor units were excited by both radial and sciatic nerve stimulation; this suggests a convergence of somatosensory inputs arising from fore- and hind limbs on the same pool of masseter and digastric motoneurones. Paired stimulation of the two nerves did not induce any summation of the responses; this finding suggests that the two inputs, reaching a common relay station, could give rise either to occlusion or to inhibitory interactions. Spinotrigeminal relationship evidenced in this study may be involved in the coordination of jaw and limb movements.

[Baropodometric examination for complete diagnosis of patients with cranio-cervico-mandibular disorders]

BACKGROUND

The aim of this study was to evaluate the relationship between craniomandibular disorders and postural alterations using baropodometric examination.

METHODS

All tests were carried out in the Department of Dentistry at Sassari University in a population of patients with cranio-cervico-mandibular disorders (CCMD) of various types and severity. A total of 10 subjects (mean age approximately 30 years) with this pathology were evaluated over 7 months. All patients were treated using the following protocol: objective functional and clinical examination, radiographic tests, occlusal treatment using acrylic resin plate, baropodometric test with static and dynamic posture assessment, with eyes open and closed, before and after treatment with orthesis.

RESULTS

An improved postural position was observed in 80% of cases, of which 30% showed an improvement in both static and dynamic posture, 20% only in static and 30% only in dynamic; these results highlighted the importance of baropodometric analysis in the correct treatment of patients with CCMD and postural disorders.

CONCLUSIONS

This study confirms the need for a holistic approach to odontostomatological disciplines and the importance of a modern preventive and/or therapeutic approach to orthodontic problems and CCMD, especially when fixed or removable biomechanical devices are used.

Masseter muscle activity during vestibular stimulation in man

Experimental data report that vestibular afferents affect trigeminal system activity. The aim of this work was to evaluate whether static vestibular stimulation affects the excitability of trigeminal motoneurons in man. In order to assess this, voluntary EMG activity of masseter muscles as well as duration and latency of the early and late components of EMG exteroceptive silent period were evaluated while keeping the subject in vertical position and during 20 degrees static tilt. The experiments were performed on ten adult subjects with no orofacial, neurologic and otologic disorders. Each subject sat on a chair, which kept the complex head-jaw-neck-trunk and the limbs securely fixed, in order to minimize any interference due to the activation of somatosensory and proprioceptive afferents from these districts. The subjects were instructed to contract masseter muscles at 25% of their maximum bite force and the isometric force monitoring was used as visual feedback. Exteroceptive silent period (ESP) of masseter EMG was elicited by electrically stimulating the inferior inter-incisal gum. Results showed that static vestibular stimulation induced asymmetrical responses on voluntary masseter muscle activity, which was reduced to 70.3 +/- 16.1% (mean +/- S.D.) of the control value during ipsilateral tilt and increased to 128.8 +/- 13.0% during contralateral tilt. The duration of the early (ESP1) and late (ESP2) silent periods was also affected: during ipsilateral tilt ESP1 and ESP2 duration increased to 130.0 +/- 3.5% and to 122.1 +/- 2.1% of control, respectively; during contralateral tilt it was reduced to 76.8 +/- 1.2% and to 83.0 +/- 1.7% of control, respectively. On the contrary, changes in latencies were not significant. These data evidenced an asymmetrical effect exerted on trigeminal motor activity by static tilt. Since the influence of all receptors which could be activated by static tilt, except that arising from the macular ones, was minimized in this study, it is likely that the observed effects, induced by static tilt on masseter muscle activity, were of macular origin.

[Mercury determination in human amniotic fluid]

BACKGROUND

One of the components of Ag amalgam is mercury which, owing to its organic derivatives, can pass into the organs and biological fluids. One particularly interesting but worrying aspect of this transition is the possibility that mercury may pass through the placental barrier and reach the fetus. The aim of this study was to evaluate the concentration of total mercury in human amniotic fluid and compare it with the number and occlusal extension of fillings using Ag amalgam.

METHODS

A group of 56 pregnant women were selected due to undergo amniocentesis. A dental check-up was carried out in each patient to identify the number and extension of amalgam fillings. Mercury levels in the amniotic liquid were assayed using a spectrophotometer with atomic absorption and a FIAS-amalgam technique.

RESULTS

Mercury concentrations in the samples examined ranged from a minimum of 0.00 ng/ml to a maximum of 2.55 ng/ml, mean 0.44 +/- 0.53 ng/ml. The correlations between the variables examined were evaluated by calculating the coefficient of linear regression. No direct relationship was found with mercury levels. The data obtained were used to construct a model of logistic regression showing scant statistical significance (p = 0.05) between the number of fillings and mercury levels, whereas the occlusal extension of dental repairs was significantly correlated with metal concentrations (p < 0.05).

CONCLUSIONS

The authors recommend that silver amalgam should be used with considerable caution during pregnancy.

[In vitro evaluation of mercury leakage from dental amalgam using atomic absorption spectrophotometry]

OBJECTIVE

The use of silver amalgam as a tooth filler is under constant critical review because of its mercury content. After a review of the literature on this subject, in vitro spectrophotometry was used to assay the release of mercury by these amalgams in basal conditions.

METHODS

The experiment was conducted in two phases using standard doses of amalgam. In Phase 1 Black Class I cavities were created in extracted teeth that were big enough to take the required dose of amalgam. In some cases the material was inserted in a single operation, while in others the amalgam was introduced in three stages. Some of the cavities were cleansed with cotton buds bathed in ethyl alcohol, while others were not. All the drilled teeth were imbued in a bath of artificial saliva held at a constant temperature. In the second experiment, crushed amalgam was immersed in a similar bath of artificial saliva but otherwise untreated. The saliva was assayed after different time lapses using atomic absorption spectrophotometry and the FIAS technique.

RESULTS

The results showed extremely variable but always modest quantities of free mercury in the artificial saliva.

CONCLUSIONS

The findings suggest that not all the mercury available in the amalgamation phase is involved in the formation of the crystalline reticulum and that the percentage of mercury bonded is different every time. While the titre of free mercury encountered was always extremely low and hard to predict, it cannot be ignored.

Trigeminal integration of vestibular and forelimb nerve inputs

Experiments were carried out on anaesthetized guinea pigs to evaluate whether vestibular and somatosensory informations converge upon the same trigeminal motoneurones and, if so, how they interact in the modulation of their activity. It was found that excitatory responses occurred in these motoneurones when an appropriate electrical stimulation was applied to the common radial nerve. The same was true if the electrical stimulus was applied to the vestibular ampullae. In another set of experiments the stimulation was applied both to the vestibular ampullae and to the common radial nerve at various time-intervals. The amplitude of the motoneuronal responses to common radial nerve stimulation was reduced when preceded by a vestibular stimulation. The same was true when the sequence of stimulations was reversed: in this case there was a decrease in amplitude of the testing response to vestibular stimulation. The degree of these reductions depended upon the time-interval elapsed between the afferent stimulations. The maximal degree of depression was observed at 4-6 ms time-interval for conditioning vestibular stimulation and at 10-12 ms time-interval for conditioning radial nerve stimulation. It appears, therefore, that somatosensory and vestibular signals may modulate the activity of trigeminal motor units innervating masticatory muscles, suggesting that extratrigeminal afferents may control the contraction of these muscles.

[Fever of unknown origin in the elderly of the 90's]

MATERIALS AND METHODS

Eighteen elderly patients (mean age 76.3 +/- 6.9 years) with fever of unknown origin (FUO) are studied sequentially and prospectively from January 1994 to December 1996. The classic Petersdori's criteria of FUO are no more valid for the elderly. The fever of more than 3-4 weeks duration is the only criterion to be considered, the fever is frequently under 38.5 degrees C and the elderly patient is often studied for more than 1 week outside the hospital.

RESULTS

The most frequent underlying conditions were: malignancies in particular haematological diseases, followed by multisystem diseases and infections, tuberculosis "in primis".

CONCLUSIONS

Selected investigations directed to the most frequent underlying conditions of FUO in the aged individuals overcome the financial cost and the patient discomfort of the tests since an identified curable disease can improve the life expectancy and quality.

Trigeminal motoneuron responses to vestibular stimulation in the guinea pig

Experiments performed in the guinea pig were aimed at evaluating the effect of electric or caloric stimulations of the vestibular afferents on the electrical activity of the jaw-closing and jaw-opening trigeminal motoneurons. Results showed that masseter and digastric motoneurons mainly responded to vestibular ampullar activation with excitatory responses, with latencies being shorter for contralateral than ipsilateral ampullar stimulation. Differences in latencies between the jaw-closing and jaw-opening trigeminal motoneurons were observed: the masseter motoneurons constantly responded about 2 msec earlier than the digastric motoneurons. These results suggest that the vestibular-trigeminal relationship is quite complex and uses multiple systems to connect the vestibular apparatus with the trigeminal motor nuclei. From the functional point of view, the vestibular-trigeminal relationship may play a role in the dynamic control of the jaw muscle tone during head movements.

Vestibular and somatosensory afferents modulate masseter muscle activity

The aim of the research was to investigate whether somatosensory impulses starting from the forelimbs could modulate masseter muscle activity in anesthetized guinea pigs. The effect of interactions between radial nerve and vestibular stimulations on the masseter motor unit responses was also studied. Results show that electrical stimulation of both radial nerves induces responses in the masseter motor units most frequently characterized by excitation at latency ranging from 14 to 29 ms. The radial nerve responses were strongly reduced by conditioning electrical stimulation of the vestibular ampullar receptors. Similarly, the vestibular responses were reduced by conditioning radial nerve stimulation. The natural activation of the vestibular macular receptors can either decrease or increase the masseter motor unit responses evoked by electrical stimulation of the radial nerve. These complex inhibitory-excitatory interactions between the two sensory inputs could control the masseter postural tone in relation to the head and limb positions in space.

Hypoglossal responses elicited by periodontal afferent activation in the rat

Mechanical stimulation of the ipsilateral incisor tooth in the rat evoked reflex discharges in the hypoglossal nerve branch innervating the intrinsic and extrinsic tongue muscles. Stimulation elicited biphasic potentials in the whole XIIth nerve and influenced the unitary firing rate in 54 out of 80 fibers tested. The fiber responses were characterized by excitation or inhibition in frequency discharge or sequences of excitation-inhibition or inhibition-excitation. The results observed suggest that the periodontal-hypoglossal reflexes play a role in the control of tongue position during mastication.

Masseter muscle responses to forelimb nerve stimulation in the guinea pig

These experiments were aimed at clarifying the spinal-masseteric connections by observing the effect of electrical stimulation of radial nerve afferents on masseter muscle activity. Spontaneous and evoked electrical responses of the masseter motor units were recorded with tungsten microelectrodes and analysed on computer. Results show that electrical stimulation of both radial nerves induces responses in single masseter motor units. The response patterns were characterized most frequently by excitation, but also by a sequence of excitation inhibition. The latency in masseter muscle responses were found to be lower in contralateral recordings: 18.26 +/- 4.04 msec (x +/- SD) compared with a latency of 24.3 +/- 5.25 msec in ipsilateral recordings. These observations confirm the hypothesis that somatosensory impulses eminating from the radial nerve participate in the postural control of the masseter muscle aimed at maintaining correct jaw position during forelimb displacement.

[Proposal for a dynamic study of the temporo-mandibular joint, using a computerized image analyzer]

With the aim to go deep into the knowledge of the morpho-functional anatomical characteristics of the temporo-mandibular joint in humans, a dynamic method of study by means of a computerized analyzer of images is suggested. The acquired advantages are the following: a) the accuracy of evaluation of the chosen morphometric parameters; b) the working speed, from which results: c) the possibility to increase adequately the number of cases and d) the possibility to easily investigate many parameters with a very high accuracy of the quantitative results. Both right and left temporo-mandibular joints of adult individuals aged from 18 to 53 have been studied utilizing lateral tomographies focused at 3.3 mm to the lateral surface of the condylar head. The evaluations were done both in the position of completely closed mouth and in extreme opening. From the barycentre of the condyle several straight lines were drawn according to the figure 2. The length of the segment a-b (distance of profiles of the condyle and mandibular fossa) were evaluated in all the lines counter-clockwise and the results submitted to a statistical analysis. The results furnish very good information on the normal or pathological anatomical characteristics, of the joint.

[Metabolism of ornithine in human gingival tissue]

The behavior of two enzymes of the ornithine pathway, leading to the formation of proline and, eventually, of collagen, arginase and ornithine oxo-acid aminotransferase has been investigated in normal and inflamed gingival tissue. Both enzymatic activities show a statistically significant decrease in pathological samples as compared to normal ones. The data on arginase activity may be in agreement with the already documented low level of urea in pathological gingival fluid, while a decrease of the ornithine aminotransferase activity could be linked to the phenomenon of gingival retraction, i.e. the lack of complete regeneration of gingival tissue usually observed in chronically inflamed subjects, that would be reasonably parallel to a decreased proline/collagen synthesis.

[Dental caries and socioeconomic development of Sardinian population]

A statistical survey has been carried out on the incidence of caries in the population of Sardinia. It is shown that the DMF index has grown steadily from 2.6 among the young (0-12 year old) to 13.07 in the group aged between 20.1 and 30. The socioeconomic changes of the past thirty years in Sardinia are looked at in an attempt to explain this phenomenon.

Synthetic peptides including acidic clusters as substrates and inhibitors of rat liver casein kinase TS (type-2)

The hexapeptides AcSer-Glu-Glu-Glu-Val-Glu and Ser-Glu-Glu-Glu-Glu-Glu, reminiscent of the sites phosphorylated by type-2 casein kinase TS in troponin T and glycogen synthase, respectively, have been synthesized and tested as phosphorylatable substrates for casein kinase TS as well as for other protein kinases. Both peptides are readily phosphorylated by casein kinase TS but not, to any detectable extent, by either cAMP-dependent protein kinase or phosphorylase kinase. Phosphorylation by type-1 casein kinase S was almost negligible. On the other hand the hexapeptide Ser-Glu-Glu-Glu-Ala-Ala is phosphorylated much more slowly and the hexapeptide Ser-Glu-Glu-Ala-Ala-Ala is almost unaffected by casein kinase TS. While the Vmax values of casein kinase TS with the acidic hexapeptides are comparable to those obtained with the corresponding protein substrates, the apparent Km values for the peptides are about two orders of magnitude higher than those for the protein substrates. The heptapeptide Arg-Ser-Glu-Glu-Glu-Val-Glu is a very poor substrate of casein kinase TS in comparison with the corresponding hexapeptide lacking the N-terminal Arg; it is, however, a competitive inhibitor toward the protein substrates, exhibiting a Ki similar to those of Ser-Glu-Glu-Glu-Glu-Glu and (Glu)5 which, in turn, are one order of magnitude higher than that of (Glu)10. It is concluded that the minimum structural requirement of type-2 casein kinases consists of a phosphorylatable residue followed by an acidic cluster, whose length is critical for the binding to the enzyme. Additional residues on the N-terminal side are not required, but their nature can influence the transphosphorylation reaction considerably.

Synthetic peptides reproducing the site phosphorylated by cAMP-dependent protein kinase in protein phosphatase inhibitor-1. Effect of structural modifications on the phosphorylation efficiency

The hexapeptide (Arg)2-Pro-Thr-Pro-Ala (T1) and octapeptide (Arg)2-Pro-Thr-Pro-Ala (T5), reproducing the phosphorylatable site of protein phosphatase inhibitor-1, a physiological target of cAMP-dependent protein kinase, and five related peptides were synthesized by the method in solution. The phosphorylation rates of such peptides by cAMP-dependent protein kinase and their kinetic parameters have been determined and compared with those of the hexapeptide (Arg)2-Ala-Ser-Val-Ala, reproducing the phosphorylatable site of rat liver pyruvate kinase. The results obtained show that both the presence of threonine instead of serine and the adjacent C-terminal proline represent highly unfavourable factors seriously impairing the protein kinase reaction by both increasing Km and depressing V. On the other hand the N-terminal proline is compatible with high phosphorylation rates and the row of four rather than two consecutive arginines improves the phosphorylation efficiency by lowering tenfold the Km, without affecting the V. The extension of the hexapeptide T1 on its C-terminal side to give the derivative (Arg)2-Pro-Thr-Pro-Ala-Thr-Val-Ala has no significant effect on the kinetic parameters. Moreover no relationship between the phosphorylation efficiency and the predicted secondary structures around the target residue could be evidenced. Therefore the local structural features of the phosphorylatable site of inhibitor-1 cannot fully account for the fast phosphorylation of this regulatory protein. Other factors must optimize the protein kinase reaction.

Synthetic and binding studies on the postulated calcium binding site I of calmodulin

The synthesis of the dodecapeptide [sequence (20--31)] representing the hypothetical calcium binding site I of calmodulin by classical methods in solution is described. The interaction of this synthetic calmodulin fragment with calcium ions has been investigated by CD in water and in 98% trifluoroethanol solution. Calcium ions have no effect on the dichroic absorption of the dodecapeptide in aqueous solution in the wavelength range 200-250 nm. However, in 98% trifluoroethanol a linear variation of the CD properties has been observed as a function of the Ca2/peptide molar ratio. The CD results indicate the formation of a 1 : 1 calcium-dodecapeptide complex with a very high binding constant.