Showing papers by "University of Gothenburg published in 1983"

Progression of periodontal disease in adult subjects in the absence of periodontal therapy

Abstract: Progression of periodontal disease in adult subjects in the absence of periodontal therapy was monitored in 2 populations. One group of 64 Swedish subjects (mean age 40.5 years at entry) with mild to moderate periodontal attachment loss was monitored for attachment level changes at baseline, 3 and 6 years. A second group of 36 Americans (mean age 34.3 years at entry) with advanced destructive periodontal disease was monitored for attachment level changes at baseline and 1 year. Of 4101 sites examined at baseline and at 3 years in the Swedish subjects, only 158 sites (3.9%) showed attachment loss of more than 2 mm. No measurable change was found in 1440 sites (35.1%). Of 4097 sites examined at 3 and 6 years, 67 sites (1.6%) showed attachment loss greater than 2 mm; 57.4% of sites showed no measurable change; and 19 sites (0.5%) showed a decrease in probeable attachment level of more than 2 mm. During the 6-year interval, 523 sites (11.6%) showed attachment loss of more than 2 mm; 20% of sites showed no measurable change and 11 sites (0.2%) showed more than 2 mm of attachment "gain". Approximately 50% of sites that showed no measurable change in the first 3-year period showed loss in the next 3 years. In contrast, of the sites which showed some level of attachment loss in the first period, approximately 2/3 showed no loss in the second monitoring period. Of 3210 sites monitored in the American subjects, 102 sites (3.2%) exhibited more than 2 mm of additional attachment loss; 26% of sites showed no measurable change and 138 sites (4.3%) showed a decrease in probeable attachment level of more than 2 mm. The association between attachment level changes and initial attachment level (baseline) was examined by regression analysis. The slopes of the regression lines for both populations were not consistent with a hypothesis that sites with more advanced attachment loss are more prone to additional destruction, in the absence of treatment, than sites with initially less attachment loss. In the American group, some sites with initially advanced attachment loss, exhibited a decrease in probing attachment level.

The Circulatory System

Abstract: Profound changes in the demands on the circulatory system have occurred during the evolution of the vertebrates from the aquatic forms to the more advanced terrestrial forms. These changes reflect a variety of anatomical and functional alterations, and also the adjustment from aquatic life at zero gravity to the demands of terrestrial life. The best documented driving force in the evolution of the vertebrate cardiovascular functions is the need for an efficient transport of respiratory gases between the gas exchanger (skin, gill, lung) and the tissues (Johansen and Burggren 1980, Johansen 1982).

The Alimentary Canal

Abstract: The functions of the alimentary canal of the vertebrates are basically to (1) receive and act as a reservoir for ingested food and fluid; (2) process the food chemically and physically; (3) absorb water and nutrients and (4) dispose of the wastes. These functions of the gut are controlled by a multitude of systems which regulate the muscular activity of the gut wall, the secretion of digestive juices into the lumen of the gut, and the blood flow in the mucosa. The control systems include the coordinated reflexes of the enteric nervous system and some reflexes that also include extrinsic autonomic pathways (vagal, splanchnic and pelvic). In addition paracrine cells release substances that affect the adjacent cells, and endogenous endocrine systems exert control over the gut motility and, especially, the secretory activity of the gastric and intestinal glands (Larsson 1980).

Contribution of adhesion to bacterial persistence in the mouse urinary tract.

Abstract: The affinity of uropathogenic Escherichia coli to kidneys and bladders of experimentally infected mice was shown to be determined in part by the adhesive properties of the infecting bacteria. Mice were infected with various pairwise combinations of two homogeneic sets of bacteria: (i) mutants derived from a human pyelonephritis E. coli isolate which were selected to express either or both adhesins specific for globoseries glycolipid receptors or for “mannosides”; and (ii) transformants of a normal fecal isolate which harbored recombinant plasmids encoding the genes for one or the other adhesin or which harbored only the vector plasmid. The relative efficiency of survival of the strains to be compared was evaluated in each animal by plating on selective media of samples of homogenized kidneys and bladders taken 24 h after intravesical inoculation. The presence of adhesins specific for globoseries glycolipid receptors, which mediate the in vitro mannose-resistant attachment to human and mouse uroepithelial cells, enhanced bacterial recovery from both kidneys and bladders of infected animals. The addition to the infecting strain of adhesins binding mannoside residues further improved bacterial recovery from the bladder, but not from the kidney. The mutants and transformants with adhesins binding only mannosides were recovered in higher numbers from the bladder than those expressing adhesins specific for the globoseries glycolipids only. There was apparent selection in vivo decreasing expression of mannoside binding adhesins in the kidneys, but not in the bladders, of animals infected with the mutant expressing both types of adhesins. Regardless of adhesive properties, the mutants of the pyelonephritis isolate were recovered in significantly higher numbers than the fecal isolate with adhesins encoded on recombinant plasmids. We conclude that the adhesive properties in part determine the localization and retention of bacteria in the mouse urinary tract. However, the addition of adhesins to a commensal E. coli strain was not sufficient to confer colonization capacity comparable to that of a pyelonephritis strain.

Infantile autism: A total population study of reduced optimality in the pre-, peri-, and neonatal period

Abstract: Twenty-five autistic children, constituting a total population sample of children with infantile autism, were compared with 25 sex- and maternityclinic-matched controls for occurrence of reduced optimality in the pre-, peri-, and neonatal period, as noted in medical records. Autistic children showed greatly increased scores for reduced optimality, especially with regard to prenatal factors. The findings are at odds with early reports that children with autism had not suffered potential brain injury. The reasons for the discrepancy are discussed.

Electron microscopic analysis of the bone-titanium interface.

Abstract: Ten cylindrical implants, made of polycarbonate and covered with a 120-250-nm-thick layer of pure titanium, were implanted into each tibial metaphysis of five rabbits. Observation time was 12 weeks. The implants were surrounded by mature, living bone. No soft tissue intervened between bone and implant at any point. With TEM microscopy the titanium was shown to be bordered by a 20-nm-thick layer of proteoglycans, showing the characteristics of ground substance, and separating the collagen from the implant surface. Cells at the interface were likewise separated from the titanium by such a layer. Hydroxyapatite crystals were observed within the ground substance layer, occasionally seemingly in direct contact with the titanium. Normal mineralization was present 100-500 nm from the implant surface.While this study aims at defining interface anatomy, it also shows that macroscopi-cally smooth-surfaced titanium can readily heal into bone without a soft tissue envelope. This could be of help for materials' choice...

A Model for the Exchange of Water and Salt Between the Baltic and the Skagerrak

Abstract: A model for the exchange of salt and water between the Baltic and the Sea (the Skagerrak) is presented. Because of strong inter-basin interactions in the Baltic entrance area, the model must include the Kattegat and the Belt Sea. These are modeled by horizontally homogeneous two-layer sub-models. The most prominent dynamical properties of the sub-models are wind-driven entrainment flows and rotational-baroclinic, hydraulic controls. The model is driven by a meteorologically forced barotropic transport Qh [calculated from the freshwater supply to the Baltic (Qf) and the sea level fluctuations in the Kattegat], and turbulent entrainment flows coupled to the wind speed W and, in the Belt Sea, also to the barotropic transport. The most important bathymetric features of the basins are included. The model equations are integrated numerically for a test period of 1½ years. The stratification in the Kattegat, as well as in the Belt Sea, is quite well predicted. It is found that approximately one-half of ...

Five-year experience with skin-penetrating bone-anchored implants in the temporal bone

Abstract: A method for stable integration of titaniumim-plants in bone tissue has been developed at the University of Gothenburg, Sweden. Screw shaped implants have been inserted in the temporal bone using a delicate surgi cal technique. After healing-in of the implants it is, in a later seance, possible to penetrate the skin to establish a reaction-free percutaneous passage. An up to 5-year clini cal follow-up has shown the possibilities of this new meth od in the treatment of patients with e.g. certain hearing disorders or facial defects after tumour surgery.

Urinary Recovery of N-Formimidoyl Thienamycin (MK0787) as Affected by Coadministration of N-Formimidoyl Thienamycin Dehydropeptidase Inhibitors

Abstract: N-Formimidoyl thienamycin (MK0787) undergoes renal metabolism by a dipeptidase, dehydropeptidase I, located on the brush border of the proximal tubular cells. The effects of two inhibitors (MK-789 and MK-791) of dehydropeptidase I on the pharmacokinetics of N-formimidoyl thienamycin were studied in 41 healthy subjects receiving various combinations of N-formimidoyl thienamycin and MK-789 or MK-791. Both inhibitors affected the plasma kinetics of N-formimidoyl thienamycin only to a small extent. Plasma concentrations and the area under the plasma concentration curve increased about 20% with a proportional decrease in plasma clearance. Plasma half-life was not altered significantly. Coadministration of MK-789 or MK-791 resulted in uniform and marked increases in urinary recovery and renal clearance of N-formimidoyl thienamycin. Thus, at an N-formimidoyl thienamycin/MK-791 ratio of 1:0.25 or higher, the urinary recovery was about 72% in all subjects, whereas it varied between 7.7 and 43% when N-formimidoyl thienamycin was given alone. The ratio of the N-formimidoyl thienamycin and MK-791 doses affected response. At relatively higher doses of MK-791, significant increases of N-formimidoyl thienamycin urinary recovery, renal clearance, and urine concentrations occurred during the later part of the 10-h observation period after each administration. At a 1:1 ratio of the two drugs, the inhibition of renal metabolism of N-formimidoyl thienamycin was maintained for at least 8 h, whereas renal clearance declined as soon as 4 h after the administration of a 1:0.25 ratio. The results indicated that MK-789 and MK-791 alter the renal excretion of N-formimidoyl thienamycin from glomerular filtration plus tubular secretion to glomerular filtration only, possibly by competitively inhibiting the penetration of N-formimidoyl thienamycin into the proximal tubular cells.

Prevalence of Streptococcus mutans with different colonial morphologies in human plaque and saliva.

Abstract: – Plaque and saliva samples were obtained twice from 58 children at an interval of 1 year and examined for the prevalence of Streptococcus mutans on Mitis salivarius (MS) and Mitis salivarius bacitracin (MSB) agar. Two types of S. mutans colonies with different colonial morphologies were seen on both media. They were serologically identified as serotypes c/e/f and d/g respectively. The first type, morphogroup c/e/f, had the typical “frosted-glass” appearance. It was the most prevalent and was found in 97% of the children. The second type, morphogroup d/g, had a creamy marzipan consistency with a dull, granular surface, gray to brown in color and often with some liquid around or on top of the colony. Group d/g was detected in 21 children (36%) and then together with colonies of group c/e/f. Children infected with single or multiple morphogroups of S. mutans generally harbored the same groups 1 year later. There was a significant positive correlation between the proportion of S. mutans in plaque and their numbers in saliva.

Use of metronidazole as a probe in the study of human periodontal disease

Abstract: The present investigation was performed to test the hypothesis that the persistence of inflammatory periodontal disease in human subjects is incompatible with the elimination of the anaerobic segments of the subgingival microbiota. 16 human subjects participated in the trial. They were selected on the basis of advanced periodontal disease which had produced at least 4 pairs of contra lateral teeth with advanced disease. At the Baseline examination the diseased sites were characterized by assessment of plaque, gingivitis, probing depth and attachment level. In addition, the composition of the subgingival microbiota was determined. One pair of sites was subjected to biopsy. In the tissue samples the size of the inflammatory cell infiltrate was assessed. Following the Baseline examination the patients were randomly distributed into 2 treatment groups, test and control. The patients of the test group received metronidazole for 3 periods of 2 weeks each, separated by intervals of 8 weeks. In addition, all patients received detailed oral hygiene instruction and a series of subgingival scalings involving 2 quadrants of the dentition, either the right or the left jaw quadrants, Reexaminations were performed 2, 10, 20, 30 and 50 weeks after the Baseline examination. Biopsies from the predetermined sites were obtained at the reexaminations performed 2,20 and 50 weeks after the initiation of the therapy. The results demonstrated that the elimination of metronidazole sensitive bacteria from the subgingival microbiota resulted in the disappearance of clinical and histopathological signs of periodontal disease. Metronidazole has a unique bactericidal range against anaerobic bacteria. The present findings, therefore, emphasize the central role played by the anaerobic segments of the subgingival plaque for the maintenance of the inflammatory component of periodontal disease.

Radiographic evaluation of endodontic therapy and the influence of observer variation.

Abstract: In radiographic evaluation of the results of endodontic therapy the development or persistence of periapical radiolucencies often serve as criteria for therapeutic failure. In the present study the influence of inter- and intraexaminer variation on these results was investigated. Three endodontists and three radiologists interpreted periapical conditions and quality of root filling seal in radiographs of 119 endodontically treated roots. Consensus on the presence of periapical lesion was reached in 27% of cases classified as pathologic. In 6% reports of increased width of the periodontal membrane space accorded. The examiners agreed completely on normal periapical conditions in 37% of the cases. On assessing the quality of root filling seal the opinions of observers differed even more. Complete agreement on cases with adequate and defective seal was reached in 25% and 12%, respectively. For the individual examiner the widened periodontal membrane space was the diagnosis most difficult to reproduce. The present study indicates that the large variation noted among clinical and radiographic studies on the results of endodontic therapy could partly be explained by difficulties in defining and maintaining criteria for radiological evidence of periapical disease.

OBJECTIVE NEWS REPORTING General Premises

Abstract: First, the concept of objectivity in news reporting is presented in a scheme, assumed to contain its main components. The author's practical experiences from eight major objectivity studies, in which the components are operationalized and applied in content analyses, are reported and discussed. Finally, it is suggested that the tested criteria of objectivity should be complemented by an interest theory, in order to deal with the fundamental problem of the significance of different news items.

Role of attached gingiva for maintenance of periodontal health. Healing following excisional and grafting procedures in dogs.

Abstract: The present study was undertaken to analyze the role of attached gingiva for the maintenance of periodontal health in sites with normal and reduced height of the supporting apparatus. Furthermore, the effect of excision and grafting of gingiva on some parameters describing dimensions and location of the periodontal tissues was evaluated. 7 beagle dogs were used. A baseline examination comprised assessments of dental plaque, gingival conditions, attachment level, position of the gingival margin and width of the keratinized and the attached gingiva. In the right side of the jaws (experimental side) a 6-month period of periodontal tissue breakdown was followed by surgical excision of the entire zone of the gingiva. After another 4-month period of healing with daily plaque control, a gingival graft was inserted in one quadrant of the experimental side to regain a zone of attached gingiva while the other quadrant of the experimental side was left ungrafted. In the left side of the jaws (control side), the teeth were subjected to daily meticulous plaque control during the entire study. In one of the control quadrants the entire zone of the keratinized and attached gingiva was excised at a time point corresponding to the grafting procedure in the experimental side, while the gingiva in the remaining control jaw quadrant was left unoperated. Clinical examinations of all control and experimental tooth units were repeated at certain time intervals during the course of the study. The final examination was carried out 4 months after grafting. The results of the experiment showed that in sites exposed to careful plaque control measures gingival health could be established and maintained without sign of recession of the gingival margin or loss of attachment, independent of (1) presence or absence of attached gingiva, (2) width of keratinized gingiva or (3) height of the supporting attachment apparatus. Following surgical excision of the entire gingiva, all buccal sites regained a zone of keratinized gingiva, but most sites were lacking attached gingiva. Furthermore, grafting of gingival tissue significantly increased the width of the keratinized and the attached gingiva but had no obvious effect on the position of the gingival margin or the level of the attachment.

Effect of long-term tetracycline therapy on human periodontal disease

Abstract: The present investigation was performed to study the effect of long-term, low dosage tetracycline therapy on advanced periodontal disease in humans. 14 volunteers participated in the trial. Each of the participants had at least 4 pairs of diseased sites around contralateral premolars and incisors with deep pockets and advanced bone loss. The trial extended over a 50-week period and was designed as a double-blind split-mouth study. A Baseline examination included assessments of oral hygiene, gingival conditions, probing depth, attachment level and analysis of the composition of the subgingival microbiota in samples obtained from 8 selected diseased sites. All participants received oral hygiene instruction. In each patient 2 quadrants of the mouth, chosen at random, were treated by scaling and root planing. The 2 remaining quadrants were left unscaled. Following the Baseline examination the patients were randomly distributed into 2 groups of 7 members each. In one of the groups the patients received tetracycline on a daily basis during a 50-week period. The participants of the control group received placebo. Reexaminations were performed 2, 10, 20, 30 and 50 weeks after the Baseline examination. The findings demonstrated that in patients with advanced periodontal disease long-term tetracycline therapy in the absence of scaling resulted in the establishment of a subgingival microbiota almost devoid of motile bacteria and in markedly reduced signs of gingivitis, probing depth and attachment loss. In fact, the alterations observed as a result of tetracycline administration to patients with excellent self-performed plaque control were similar to those obtained by conventional scaling and root planing in the control group.

Dopamine receptor agonists: intrinsic activity vs. state of receptor.

Abstract: Based on observations with the novel dopamine-receptor agonist 3-(3-hydroxyphenyl-)-N-n-propylpiperidine, 3-PPP, especially its levorotatory enantiomer, it is proposed that the intrinsic activity of a receptor agonist depends in part on the responsiveness of the receptor; this in turn is determined by the degree of previous agonist occupancy on the receptor. A change in occupancy will induce a slow conformational change, influencing the responsiveness. This may constitute an important aspect of receptor adaptation and may help to explain otherwise puzzling phenomena,e.g. that compounds such as (−)-3-PPP or transdihydrolisuride can act as strong dopamine-receptor agonists in some locations and as antagonists in others. The observations discussed in the present paper may be interpreted to indicate that the dopamine receptors in different locations are, in fact, derived from a homogeneous receptor population, though in a varying state of adaptation. Thus it may prove worth-while to reconsider the various subclassifications of DA receptors proposed so far.

Cardiovascular Adjustments to Diving in Mammals and Birds

Abstract: The sections in this article are: 1 Historical Landmarks 2 The Basic Problem for Diving Animals 3 Decreased Sensitivity to Asphyxia 4 Oxygen Stores and Principles of Their Utilization 5 Cardiovascular Adjustments During and After Diving 5.1 General Aspects 5.2 Cardiac Output 5.3 Regional Circulation During Diving and on Emersion 6 Morphological Specializations in Vascular Beds of Diving Animals 6.1 Arteries 6.2 Shunts 6.3 Veins 7 Metabolic Consequences 8 Central Integration of Cardiovascular Responses 8.1 Medullary Reflex Mechanisms 8.2 Suprabulbar Influences 8.3 Other Reflex Influences 9 Diving Responses in Humans and Some Clinical Applications 9.1 Responses in Humans 9.2 Clinical Applications

Psychological reactions to edentulousness and treatment with jawbone-anchored bridges.

Abstract: Total edentulousness can lead to chewing problems as well as to feelings of insecurity and inferiority and considerable psycho-social problems. For many people a conventional removable denture is unsatisfactory. A new method - osseointegration - involves a titanium screw being operated into the jawbone and the attachment of a fixed bridge. In a controlled study, 26 patients were examined pre- and postoperatively 3 months and then 2 years after the insertion of a jawbone-anchored bridge. The majority of them state that there has been a significant improvement in their lives, that they have regained confidence in themselves, and that, in contrast to a conventional denture, they accept the fixed bridge as part of their body. More attention should be focused on psychological reactions to total edentulousness. Individuals who cannot be rehabilitated by means of conventional prosthetic procedures should be given the opportunity of having a jawbone-anchored bridge inserted. Such treatment means an odontological and psycho-social restitutio ad integrum.

Significance of frequency of professional tooth cleaning for healing following periodontal surgery

Abstract: The present investigation was undertaken to study the significance of frequently repeated professional tooth cleaning for healing results following periodontal surgery. 24 patients suffering from moderately advanced periodontai disease were selected for the study. Following a Baseline examination comprising asses.sment oforal hygiene status, gingival conditions, probing dcplhs and attachment levels, all patients were given detailed instruction in proper oral hygiene mea.sures. They were then subjected to periodontal surgery (ising the modified Widman flap procedure. During the initial 6 months after surgery ail patients were enrolled in a maintenance care program which included measures such as scaling and professional tooth cleaning. The patients were randomly distributed into 3 different maintenance care groups. S patients (Group 1) received maintenance care once every 2 weeks, another 8 patients (Group 2) received a similar treatment once every 4 weeks while the remaining % patients (Group 3) were recalled once every 12 weeks. Following a reexamination at the termination of this 6month period the recall program was changed. Thus, during the subsequent 18 months of maintenance {the maintenance phase) al! 24 patients were recalled for prophylaxis once every 3 months. A final reexamination was performed 24 months after completion of active therapy. The reexamination performed 6 months after surgery revealed that while patients who had been recalled for professional tooth cleaning once every 2 weeks had low numbers of inflamed gingival units and deep ( > 3 mm) periodontai pockets, test subjects recalled less frequently exhibited an increasing number of inflamed gingival units and deep pockets. In addition, the frequency of sites exhibiting attachment loss of > 1 mm was closely related to the frequency of maintenance care. Patients recalled once every 12 weeks for maintenance therapy had 3 times the number of sites with attachment loss(>l mm) as compared to those who were recalled once every 2 weeks. With the use of regression analysis critical probing depth values were calculated. Thi.s analysis showed that while the critical probing depth value was Jow in patients frequently recalled during the healing phase, this parameter adopted gradually increasing values in patients recalled with les.s frequent intervals. Between the 6and 24-month reexaminations there were no significant alterations of the oral hygiene status, the gingival condition or the probing depth and attachment level data in any of the 3 groups of patients. Periodontal therapy aims at establishing heaiings from different research groups indicate thy gingivae and arresting the progressive dethat while the technique used during surgery struction of the supporting apparatus. Surgical (e.g. gingivectomy, apically positioned flap, procedures are often employed in the treatment replaced flap, curettage) plays only a minor role of periodonta! disease (I) to obtain accessto the for the overaii result, the quality of the mainroot surfaces for proper debridement and (2) to tenance care program foliowing surgery seems excise soft and hard tissues in such a way that to be of decisive importance. Rosling et al. ideal conditions for healing are provided. Find{i976b) and Nyman et al. {1977} studied the MAINTENANCE CARE AFTER PERIODONTAL SURGERY healing capacity of the periodontal tissues following 5 different modes of periodontal surgery. They reported that healing occurred in all patients whose oral hygiene was professionally maintained at an optima! level following active treatment, while recurrence of disease was an obhgatory finding in patients unable to meet requirements regarding a proper oral hygiene standard. Similar findings have subsequently been presented by e.g. Poison & Heijl (1978), Isidor (1981), Lindhe et al. (1982a, b). On the other hand, recent observations by Pihlstrom et al. (1981) and Ramfjord et al. (1982) tend to place more emphasis on regularly repeated (once every 3 months) scaling and root planing, than on professionally or self performed oral hygiene measures for the success of periodontal therapy. The aim of the present clinical trial was to further evaluate the relative importance of the plaque control program maintained immediateiy following periodonta! surgery for healing results. Material and Methods The study was carried out in 24 subjects, 13 females and ! 1 males, 32-72 years of age, who were randomly selected from the patients referred to the Department of Periodontology, University of Gothenburg, for treattnent of moderately advanced periodonta! disease. Prior to treatment al! patients were examined in order to determine their orai hygiene standard, gingiva! condition and degree of periodontal tissue breakdown. At this Baselitie exatttinalion the following parameters were investigated: Oral hygiene status. Presence of p!aque was assessed on a!l tooth surfaces using the criteria of the Plaque Index system (Silness & Loe 1964). Individual mean values were ca!cu!ated. Gingival condition. Gingiva! inOammation was assessed using the criteria of the Gingival Index system (Loe & Silness 1963). Individual mean vaiues were calculated. Probing depth. Individually fabricated acrylic stents were instaUed prior to the c!inica! examination. At each tooth surface probing depth and the dinica! attachment !evel (see below) were measured from reference points prepared in the stents to enable repeated assessment of these parameters at the same site in the course of the study. The probing depth was measured with a calibrated probe. The diameter of the probe tip was 0.5 mm. Attachment level. The clinical attachment ievei was measured from the reference points and expressed as the distance between the acrylic stent and the bottom of the pocket. The measurements used to determine the probing depth and clinical attachment ievei in different parts of the dentition have been described previously (Lindhe et al. 1982a). In all, 182 sites were monitored if ail 32 teeth were present. Teeth scheduled for extraction following the Baseline examination were not included in the study. Fo!!owing the Baseline examination all patients were given detailed instruction in proper ora! hygiene measures in conjunction with a \"case presentation\" session. They were then subjected to periodonta! surgery using the modified Widman f!ap procedure described by Ramfjord & Nissie (1974). Angular bony defects were not eliminated, but curetted only. For a detailed description of the surgical procedure used the reader is referred to previous papers by Lindhe et al. (1982a) and Westfeit et ai. (1983). Surgical treatment was carried out in 2 sessions with an interval of 2 weeks. Following the phase of active periodontal treatment (surgery) all patients were enrolled in a maintenance care program including professional tooth cleaning ad modum Axe!sson & Lindhe (!974). The patients were random!y distributed into 3 different maintenance groups. WESTFELT, NYMAN, SOCRANSKY AND LINDHE 1, 2 and 3. The intervals between the maintenance sessions were 2 weeks (Group 1: 8 patients), 4 weeks (Group 2: 8 patients) or 12 weeks (Group 3: 8 patients). Following a reexaminatiort after 6 months of healing (the healing phase) the recall program was changed. Thus, during the subsequent 18 months of maintenance {the maintenance phase) all 24 patients were recalled once every 3 months for prophylaxis. At each recall appointment, both during the phase of healing and the phase of maintenance, plaque was stained with a disclosing solution and, if needed, the instruction in proper oral hygiene methods repeated. This instruction comprised demonstration of the Bass' method of tooth brushing (Bass 1954) and interdental cleaning wiih the use of interproximal toothbrush, denta] floss or toothpick. Supraand subgingival scaling was carried out when indicated. Finally, the teeth were polished with a rubber cup and an abrasive paste (Jodka® polerpasta, Adaco AB, Sweden). The maintenance care program was conducted by a dental hygienist. All patients were reexamined with regard to oral hygiene, gingival condition, probing depth and clinical attachment level 6 and 24 months after completion of active therapy. The assessments were confined to the same tooth surfaces and location points where the recordings had been made at the Baseline examination. Statistical analysis The mean, standard deviation and 95% confidence intervals as well as the determination of significance of difference of means using the ttest were performed according to standard methods. Regression anaiysis was carried out to determine the so-called \"critical probing depth\", i.e. the initial probing depth below which the treatment resulted in loss of attachment and above which gain of clinical attachment occurred. The initial probing depth was used as the independent (x axis) variable. The x Table. I. Individual mean Plaque index and Gingival Index scores at tlic Ba.st'line examinaiion and percentage distribution of scores 0, I and 2+3 ai the 6and 24-month rccxaminations Indivicluelie mittlere Beurieihmgseinheiten f.^care.^) des PlaqueundGingivalindex bci der Ausgangsuntersuchung, sowie die prozentuale yerieikmg der Beurteilungseinheiten 0. I und 2+ 3 bei den Nachuniersuclningen nacb 6 und24 Mon a ten Scores individuals moyem de I'Indice de Plaque et de I'Jndice Gingival a Pcxamcn initial et distribution en % de.f .scores 0, 1 et 2+3 tors des examen.'i apres 6 et 24 mois Plaque Index score Baseiine examination (X±s.d.) Group ! Group 2 Group 3 Gingival Index score Ba.scline examination (X + s.d.) Group i Group 2 Group i 6 months Group 1 Group 2 Group 3 24 months Group 1 Group 2 Group 3 L6 + 0.6

Stiffness of Central Venous Catheters

Abstract: Catheter stiffness has been suggested to be a principal factor in the thrombogenesis encountered after central venous cannulation. However, no data have been published to date about the stiffness of central venous catheters. A method for measuring catheter stiffness has been developed. The force needed to deflect a catheter tip 1.2 mm from a fastening point was measured with the help of a cantilever beam (Grass Model DA-7). Six different sections of each catheter were measured, and the final results expressed as an average of these. Twenty-seven central venous catheters made of silicone elastomer, polyurethane, polyvinylchloride, polyethylene and teflon were tested. The bending stiffness, EI (E = elastic modulus of the material, I = moment of inertia of catheter (a geometrical property)) was below 16 X 10(-6) Nm2 for all catheters made of silicone elastomer, polyvinylchloride and polyurethane. Polyethylene catheters were stiffer, but could be made softer by reduction of their diameters. Teflon catheters were up to 10 times stiffer than the catheters in the soft group. Heparinization and radioopacity of catheters do not significantly alter their bending stiffness. In a concomitant study the results indicate that there is a significantly lower incidence of thrombus formation in catheters with a bending stiffness below 16 X 10(-6) Nm2.

Changes in segmental reflexes following chronic spinal cord hemisection in the cat

Abstract: In a companion paper (Hultborn & Malmsten 1983) it was described that ventral root discharges to stimulation of peripheral nerves became larger on the side of a chronic spinal hemisection (left) than on the other side. In the present paper, based on the same experiments, conditioning of monosynaptic test reflexes was used to study changes of both excitatory and inhibitory effects on specified motoneuronal pools. Conditioning stimulation was given to Ia afferents (reciprocal Ia inhibition, presynaptic inhibition of Ia fibers), high threshold muscle afferents, low and high threshold cutaneous afferents and motor axons (recurrent inhibition). A comparison of the efficacy of conditioning stimuli on the two sides showed that facilitatory effects were larger on the side of hemisection in a clear majority of cases. Inhibition was almost always either more efficient on the side of hemisection or equally efficient on the two sides. In control cats, facilitatory effects tended to be larger on the right side, while the results for inhibitory conditioning generally showed no clear side-bias. The increase in facilitatory effects after lesions may contribute to symptoms of spasticity.

Serologic Differentiation Between Antitoxin Responses to Infection with Vibrio cholerae and Enterotoxin-Producing Escherichia coli

Abstract: A ganglioside enzyme-linked immunosorbent assay (ELISA) was used to study and attempt to differentiate between antitoxin responses in persons infected with either Vibrio cholerae or Escherichia coli producing heat-labile enterotoxin. In most cases (69%-94%), experimentally infected North Americans and naturally infected Bangladeshis responded to either infection with significant (greater than twofold) increases in serum antibody titer to both heat-labile enterotoxin and cholera toxin. In all but one instance, the response was higher to the homologous than to the heterologous toxin, and for the Americans the homologous antitoxin titers remained significantly higher for at least one year. Determination of levels of antibodies to purified subunits A and B of cholera toxin by an ELISA showed that V. cholerae infection in most instances induced a significant response to subunit B but rarely to subunit A. E. coli infection, on the other hand, induced only slight increases in antibody titer to either subunit.

Localized bone resorption in the femur in mechanical failure of cemented total hip arthroplasties.

Abstract: In 70 total hip arthroplasties exchanged because of mechanical loosening of the stem prosthesis, localized bone resorption or scalloping was found in 33 cases. In 19 of the 33 cases the process started at the level of the tip of the stem, which in 15 cases was found to be in direct contact with cortical bone as observed in the radiographs obtained immediately after the primary surgery. In 37 failures without scalloping this metal-to-bone contact was less common. It is concluded that localized bone resorption may occur as a result of mechanical stress and in the absence of deep infection. It is also suggested that the phenomenon might be avoided by proper cementing technique and centering of the tip of the stem, perhaps with the help of a centering device.

Auditory Brainstem Responses in Childhood Psychosis.

Abstract: Auditory brainstem responses were compared in 24 autistic children, 7 children with other childhood psychoses, and 31 normal children. One-third of the autistic children showed abnormal ABR indicative of brainstem dysfunction and correlating with muscular hypotonia and severe language impairment. The children with other psychoses and the normal children showed normal results.