Cluster randomized trial to evaluate the impact of team training on surgical outcomes

Background

The application of safety principles from the aviation industry to the operating room has offered hope in reducing surgical complications. This study aimed to assess the impact on major surgical complications of adding an aviation-based team training programme after checklist implementation.

Methods

A prospective parallel-group cluster trial was undertaken between September 2011 and March 2013. Operating room teams from 31 hospitals were assigned randomly to participate in a team training programme focused on major concepts of crew resource management and checklist utilization. The primary outcome measure was the occurrence of any major adverse event, including death, during the hospital stay within the first 30 days after surgery. Using a difference-in-difference approach, the ratio of the odds ratios (ROR) was estimated to compare changes in surgical outcomes between intervention and control hospitals.

Results

Some 22 779 patients were enrolled, including 5934 before and 16 845 after team training implementation. The risk of major adverse events fell from 8·8 to 5·5 per cent in 16 intervention hospitals (adjusted odds ratio 0·57, 95 per cent c.i. 0·48 to 0·68; P < 0·001) and from 7·9 to 5·4 per cent in 15 control hospitals (odds ratio 0·64, 0·50 to 0·81; P < 0·001), resulting in the absence of difference between arms (ROR 0·90, 95 per cent c.i. 0·67 to 1·21; P = 0·474). Outcome trends revealed significant improvements among ten institutions, equally distributed across intervention and control hospitals.

Conclusion

Surgical outcomes improved substantially, with no difference between trial arms. Successful implementation of an aviation-based team training programme appears to require modification and adaptation of its principles in the context of the the surgical milieu. Registration number: NCT01384474 (http://www.clinicaltrials.gov).

Nucleotide sequence of bean golden mosaic virus and a model for gene regulation in geminiviruses

We have sequenced the genome of bean golden mosaic virus, which comprises two circular single-stranded DNA molecules (2646 and 2587 nucleotides long) of mostly unique sequence. Comparison of the sequences of bean golden mosaic virus and of cassava latent virus, which share serological relationship but are very different in host range and geographical origin, shows that each virus has a unique 200-nucleotide sequence (common region) on each 2.6-kilobase molecule of its genome. The common regions of the two viruses have no sequence homology except for a short inverted repeat near the 3' end. Six open reading frames were identified that possess considerable sequence homology between the two viruses and, in bean golden mosaic virus, may encode proteins of 15.6, 19.6, 27.7, 29.7, 33.1, and 40.2 kDa. Conserved open reading frames are found in both the viral strand and the complementary strand, are approximately the same size, and are in the same orientation with respect to the common region in both viruses. We propose that temporal regulation in geminiviruses depends on the polarity of transcription and that the common region represents a replication origin and contains elements that serve to modulate gene expression.

Complications of Ilizarov leg lengthening: a comparative study between patients with leg length discrepancy and short stature

The Ilizarov technique has been used to treat severe limb length discrepancy and short stature. However, complications of this treatment are frequent. Between 1984 and 2001, 57 patients (94 tibias) had an Ilizarov procedure for limb lengthening. Twenty patients had limb discrepancy and 37 had short stature. Their mean age was 20.2 years (range 15-34). The average limb lengthening was 8.37 cm (range 3.2-14.7), which was equivalent to 26% (range 9.2-60%) average tibial lengthening. A total of 90 complications were observed. Thirty-three unplanned procedures were required during the lengthening programme. Two patients stopped the lengthening programme. There was no difference in the complications in leg lengthening using Ilizarov technique between the group of patients with leg length discrepancy and the group with short stature. A good knowledge of the Ilizarov technique is necessary to perform a lengthening programme with a low rate of complications.

Epidemiological, clinical, biological and radiological differences between atrophic and hypertrophic patterns of hip osteoarthritis: a case-control study

OBJECTIVE

Lack of osteophytes (atrophic form) has been shown to be a factor in the severity of hip osteoarthritis (OA). The aim of this study was to determine the epidemiological, radiological and biological differences between the hypertrophic and atrophic forms of hip osteoarthritis.

METHODS

25 patients with symptomatic hip OA (ACR criteria) and classified as having an atrophic form of OA based on the lack of osteophytes on standard radiograph of the pelvis, were matched for joint space width with 25 subjects with evidence of the hypertrophic form of hip OA. OA radiological severity was assessed using a scoring system and by computer measurement of the joint space width. Angles of hip dysplasia were measured. Serum hyaluronic acid, cartilage oligomeric matrix protein, collagenase, Type I procollagen, C-terminal crosslinking telopeptide of type I collagen and tissue inhibitor of métalloproteases-1 were assayed by immunoassay and C-reactive protein by ultrasensitive immunonephelemetry. Statistical analysis was performed using logistic regression, taking into account age, sex, body mass index, and bilaterality.

RESULTS

Compared to hypertrophic OA, atrophic OA affected chiefly elderly women and was characterized by a smaller centre-edge angle and diffuse superior femoral head migration. It was less frequently bilateral. No statistically significant difference was found in the biological data between the two groups.

CONCLUSION

An atrophic bone response in hip OA occurs chiefly in women and is associated with poor coverage of the femoral head. Serum biomarkers able to demonstrate differences between the atrophic and hypertrophic patterns of OA are lacking.

[Air permeable diaphyseal obturators: efficacity of femoral cementing and prevention of associated cardiovascular disorders]

PURPOSE OF THE STUDY

Insertion of cement plugs into the femoral shaft has become an essential part of total hip arthroplasty procedures. The goal is to achieve secure cementing of the femoral component, but the pressure induced can cause serious problems. The purpose of this study was to determine the effect of a flexible bioabsorbable cement restrictor with decompression valves on cementing efficacy and to determine the effect of inserting the restrictor then the cement plug into the femoral shaft on respiratory functions.

MATERIAL AND METHODS

The restrictor was implanted in 108 patients undergoing first-intention total hip arthroplasty. The canal was prepared and calibrated before inserting the restrictor at a depth estimated at preoperative planning to be 10 to 20 mm below the tip of the femoral stem. The efficacy of the restrictor was assessed using radiographic criteria for the quality of the cement sheath and its position relative to the femoral stem. Oxygen saturation of arterial blood and end-expiration PCO2 were measured at first incision, at insertion of the restrictor, at insertion of the cement plug, and at insertion of the femoral stem.

RESULTS

The relative position of the restrictor was measured on postoperative x-rays at less than 20 mm in 75% of the patients, at 20-40 mm in 13% and at more than 40 mm in 12%. No cement leakage through the restrictor was identified on postoperative x-rays. The quality of the cement sheath was satisfactory in 71% of the patients (77 procedures), fair in 20% (22 procedures) and poor in 8% (9 procedures). For a first group of patients operated on under spinal anesthesia and optional oxygen delivered with a face mask, there was no significant difference in arterial blood oxygen saturation before the procedure and during the four explored operative times. Conversely, in a second group of patients who had general anesthesia without oxygen enrichment of the initial oxygen-nitrogen protoxide gas mixture, arterial blood oxygen saturation during the four operative times was statistically different from the preoperative value. The same observation was made for end-expiratory PCO2.

DISCUSSION

The retrictor's decompression valves did not allow cement leakage beyond the restrictor. The risk of restrictor migration after insertion and after the increased pressure due to cement plug insertion was not increased and was found to be less than rates reported in the literature. In the patients who had general anesthesia, blood gases showed a minimal, but significant, decrease during the operative times susceptible to induce increased intramedullary pressure. In patients who had a non-cemented acetabular insert, use of the pressure-valve cement restrictor appeared to stabilize these parameters.

Treatment of periodontitis by local administration of minocycline microspheres: a controlled trial

BACKGROUND

Periodontitis is an inflammatory condition of tooth-supporting tissues that is usually treated by mechanical removal of plaque and microorganisms that adhere to teeth. This treatment, known as scaling and root planing, is not optimally effective. Adjunctive therapy with locally delivered antimicrobials has resulted in improved clinical outcomes such as probing depth reduction. This article reports on the efficacy and safety of locally administered microencapsulated minocycline.

METHODS

Seven hundred forty-eight (748) patients with moderate to advanced periodontitis were enrolled in a multi-center trial and randomized to 1 of 3 treatment arms: 1) scaling and root planing (SRP) alone; 2) SRP plus vehicle; or 3) SRP plus minocycline microspheres. The primary outcome measure was probing depth reduction at 9 months. Clinical assessments were performed at baseline and 1, 3, 6, and 9 months.

RESULTS

Minocycline microspheres plus scaling and root planing provided substantially more probing depth reduction than either SRP alone or SRP plus vehicle. The difference reached statistical significance after the first month and was maintained throughout the trial. The improved outcome was observed to be independent of patients' smoking status, age, gender, or baseline disease level. There was no difference in the incidence of adverse effects among treatment groups.

CONCLUSIONS

Scaling and root planing plus minocycline microspheres is more effective than scaling and root planing alone in reducing probing depths in periodontitis patients.

[Osteoarticular disease in adults in France. A survey of 2000 persons]

PURPOSE OF THE STUDY

Seeking for a global epidemiology data on bone and joint disease in adults in France, we analyzed the problems related to bone and joint disease in a sample population to determine healthcare needs. We also examined patient referral and demand for surgical care for bone and joint disease and the degree of patient satisfaction.

MATERIAL AND METHODS

A telephone interview was conducted in a randomly sampled population of adults living in France to determine their demographic characteristics and bone and joint conditions and surgical care reported by the interviewees. Before standardizing, the sample population in the 60-year and older group was increased in order to obtain more precise information concerning degenerative joint disease. The sample included 1000 persons aged under 60 years and another 1000 persons aged over 60 years. The sample populations were matched to the French population for sex and age distribution. One hundred personal face-to-face interviews were also conducted with 100 persons residing in a nursing home. The two surveys were conducted in June and July 1999.

RESULTS

Extrapolation of the data obtained to the French population yielded a total of 12 million adults affected by a bone and joint condition during the year preceding the survey. Considering both study samples, the most frequent localizations concerned the spine and the knees. The distribution of the other localizations was age and sex dependent. The percentage of trauma-induced conditions was 31%, predominantly in men under the age of 60 years and in institutionalized individuals. Extrapolation yielded a total of 5.4 million persons who had (or expected to have) a surgical intervention due to a bone and joint condition. The percentage of surgical treatment was highest for fractures (41%) and extravertebral osteoarthritis (18%). Extrapolation to the French population yielded 0.55 million persons aged over 60 years with a hip prosthesis and 0.27 million with a knee prosthesis. Seventy-six percent of the individuals who had undergone surgery for a conditions unrelated to trauma felt their quality of life had been improved. For those who had surgery for a trauma-induced condition, 85% considered they had minimal or no sequelae. Information provided by the surgeon concerning surgical care was thought to be insufficient by 23% of the operated individuals and 43% of those who had a joint prosthesis stated they had not been informed that their implant might be changed. Management of postoperative pain was thought to be insufficient by 36% of the operated individuals.

DISCUSSION

Due to the wide field of investigation and the methodology used to collect these data, our findings cannot be easily compared with other epidemiological data. They must be considered with caution due to the sampling bias of a telephone interview and also to the bias introduced by the simplified nosology scheme used for the questionnaire and the fact that no medical validation was performed. These data do however show that a large number of adults are concerned, notwithstanding conditions occurring before the age of 18 years with the frequency of accidents during childhood and adolescence. The data collected confirm the priorities set within the framework of the Bone and Joint Decade 2000-2010.

[Progressive limb lengthening with a centromedullary nail versus an external fixator: experimental study in sheep]

PURPOSE OF THE STUDY

Progressive limb lengthening with an external fixator often leads to pin-related complications. A new technique allowing progressive lengthening with a centromedullary nail without external fixation has been developed. This original double-locked device consists of matching male and female components fitted with a continuous thread. Lengthening is achieved via a one-way ratchet system. Twelve back-and-forth movements produce 1.25 mm lengthening.

MATERIAL AND METHODS

We tested this new device on 20 sheep and compared results with external fixation lengthening in 20 other sheep. The animals were divided into groups for sacrifice on days 5, 10, 20, 45 and 90. Serial x-ray were obtained for all animals. In the 45-day and 90-day groups, histomorphometric (trichrome goldner coloration and polarized light microscopy) and densitometric studies were also performed. Bone mineral density (BMD) was determined and bone trabecular density (BTD) and trabecular bone volume (TBV) were expressed in percent of bone trabecular surface area.

RESULTS

Mean lengthening in the 45-day and 90-day groups was 39 mm for the nail and 20 mm for external fixation (1 mm/day). At 90 days, 3 sheep out of 4 had consolidated radiologically with external fixation and 2 out of 4 with the nail. BMD was slightly better for external fixation (0.811 vs 0.695/cm(2)). This difference could probably be attributed to the greater lengthening obtained with the nail. At 45 days, BMD was the same (0.6 g/cm(2)) for both devices. BTD was nearly two-fold higher for the nail compared with external fixation (59.65% vs 32.61% at 90 days), most probably due to primary bone formation. The histomorphometric study allowed an analysis of the osteoid border. Bone quality obtained in the bone regenerate with the nail was superior to that obtained with external fixation. Primary bone formation resulted from membrane ossification with direct transformation of fibroblasts into osteoblasts.

CONCLUSION

This work demonstrated that progressive lengthening can be achieved with a specifically designed centromedullary nail without iterative opening of the operative site. Tolerance to this type of device and quality of the bone regenerate are altogether satisfactory.

Induction of amelogenin and ameloblastin by insulin and insulin-like growth factors (IGF-I and IGF-II) during embryonic mouse tooth development in vitro

Insulin and insulin-like growth factors (IGF-I and IGF-II) are considered pleiotropic, acting as both mitogen and differentiation factors. Several investigators have demonstrated the expression of insulin, IGFs, their cognate receptors and IGF binding proteins during tooth morphogenesis. Previous work done in our laboratory indicated that exogenous insulin and IGFs induce the accumulation of enamel extracellular matrix on mouse mandibular molars cultured in a serumless, chemically defined medium. In order to determine the level of control of these factors in the induction of enamel biomineralization, we designed experiments to quantitate mRNAs for enamel specific-gene products. Mandibular first molars (MI) obtained from E15 Swiss Webster mice were placed in organ culture in the presence of insulin (1,000 ng/ml), IGF-I (100 ng/ml) or IGF-II (100 ng/ml) for 6, 12 and 18-days. At termination date, the RNA was extracted and the concentration of mRNAs for amelogenin, tuftelin and ameloblastin were determined using a quantitative competitive reverse transcription-polymerase chain reaction (RT-PCR) technique (PCR mimic). Our results showed that after 6-days in culture; treatment with insulin, IGF-I and IGF-II increased the synthesis of amelogenin and ameloblastin. In contrast, the expression of tuftelin mRNA was not affected by either factor. In conclusion, our studies showed that the increase in enamel matrix formation by overexpression of IGFs is the result of transcriptional regulation of enamel specific proteins like amelogenin and ameloblastin but not tuftelin. These studies also suggest that the regulatory mechanisms controlling tuftelin gene expression are different than the mechanisms regulating ameloblastin and amelogenin transcription.

Formation of the biologic width following crown lengthening in nonhuman primates

The purpose of this study was to determine if and how the biologic width is reestablished following surgical crown lengthening. Crown-lengthening surgery was performed on the right or left maxillary and mandibular central and lateral incisors of three adult monkeys, with contralateral teeth serving as unoperated controls. Twelve weeks after surgery, tissue blocks were removed for histologic analysis. The results of a histometric evaluation indicate that the biologic width is reestablished following surgical crown lengthening. The junctional epithelium generally migrates to the apical level of root planing. Space for the supracrestal connective tissue fiber groups is created by crestal resorption of alveolar bone.

Quantitative measurement of joint space narrowing progression in hip osteoarthritis: a longitudinal retrospective study of patients treated by total hip arthroplasty

OBJECTIVES

To evaluate the rate of progression of radiological joint space narrowing (JSN) in patients operated on for hip osteoarthritis (OA) and to determine its predictive factors.

METHODS

STUDY DESIGN

retrospective longitudinal trial of 61 patients who underwent total hip arthroplasty (THA) for hip OA (69 operated hips). Mean follow-up 81.2 +/- 9.9 months. Collected data: (1) standing frontal radiographs of the pelvis from diagnosis to surgery (246 films) for morphological evaluation and quantitative measurement of joint space width (JSW) (computerized reading of digitized X-rays); (2) demographic data (sex, age, body mass index, smoking status, professional and sporting activities, family history of OA); (3) clinical data (age at onset-diagnosis and THA, drug consumption, time from diagnosis to permanent disability, OA at other joints, previous THA of the contralateral hip).

STATISTICS

multivariate analysis.

RESULTS

The yearly mean narrowing (YMN) of MeanJSW was 0.43 +/- 0.43 mm/yr (median 0.29, range 0.03-2.55). YMN correlated inversely with joint space width at operation and follow-up duration, and was increased in atrophic OA (r = 0.71). The time between diagnosis and THA correlated with JSW at diagnosis, and was inversely correlated with age at onset and YMN. It was longer in patients with hypertrophic OA (r = 0.69).

CONCLUSION

Rapid progression of JSN, older age and absence of osteophytes appear to be the main factors leading to THA.

Timing of the expression of enamel gene products during mouse tooth development

In order to understand the mechanisms involved in tooth development it is important to define the timing for tissue-specific gene expression. A consequence of ameloblast cell differentiation is the sequential expression of tissue-specific genes whose products form the enamel extracellular matrix. The ameloblast phenotype has been characterized as consisting of two major classes of proteins: amelogenins and non-amelogenin proteins such as anionic enamel proteins (enamelins, tuft proteins, tuftelin, sulfated proteins) and enamel proteases. The postulated functions for the anionic enamel proteins are as nucleators for hydroxyapatite crystal formation while amelogenins control the crystal size, growth and orientation. While the amelogenins have been well characterized, detailed knowledge for anionic enamel proteins has been sparse. In the present study, we designed experiments to characterize one of the anionic enamel proteins from mouse molars, tuftelin, and to determine the timing of expression of this protein during molar tooth development. Our results showed the initial detection of tuftelin transcripts within proliferating inner enamel epithelial cells at very early stages of tooth development (13 days of embryonic development equivalent to the bud stage of tooth development). These data provide direct evidence that invalidates previous dogmas that enamel proteins were synthesized by polarized, non-dividing, fully differentiated ameloblast cells. In addition, tuftelin was found to be synthesized also by dental papilla mesenchyme cells suggesting that this protein is not enamel-specific. These data taken together open the possibility that the tuftelin present in the dentino-enamel junction could be secreted by both, preodontoblast cells and preameloblast cells. It might also suggest a possible different role for tuftelin than nucleator of hydroxyapatite crystals.

Gangliosides from normal and osteoarthritic joints

A decrease in all major gangliosides, contrasting with a marked increase in the GM3 third band (3B-GM3), has been demonstrated in osteoarthritic fibrillated cartilage. We found the 3B-GM3 in osteoarthritic fibrillated, grossly intact and osteophytic human cartilage, but it was undetectable in pig and bovine cartilage, bone, synovium, synovial fluid white cells, erythrocytes, and various extracellular tissues. We made a similar finding with lactosyl ceramide, the GM3 neutral glycolipid precursor. The search for an antibody against the 3B-GM3, as a possible specific antigenic marker of osteoarthritis (OA), was unsuccessful. However, an antibody against a molecule very close to 3B-GM3 on high performance thin layer chromatography, which will probably be identified as a glycosylphosphatidylinositol, was found in the serum of some patients with OA.

Non-human primate models for testing the efficacy and safety of periodontal regeneration procedures

Experimentally-produced defects in the non-human primate are preferred for testing the efficacy and safety of periodontal regenerative therapies. These animals closely resemble the human in dental anatomy and periodontal wound healing physiology. Defects can be produced which do not display spontaneous regeneration and which are contralaterally identical. Thus, within animals, untreated controls can be obtained to indicate the level of supporting tissues prior to therapy. The use of non-human primate models is recommended for science transfer experiments involving invasive surgery and the testing of potentially harmful new devices and pharmaceuticals.

Synthetic bioabsorbable barrier for regeneration in human periodontal defects

Guided tissue regeneration (GTR) may result in the formation of new bone, cementum, and periodontal ligament. The purpose of this study was to assess the efficacy of a resorbable synthetic material, which has been used extensively in general surgery for wound support, to promote GTR. Forty healthy patients with adult periodontitis, each having a Class II furcation defect, participated in the study. After initial therapy, mucoperiosteal flaps were elevated and furcations debrided with hand and rotary instruments. In 20 patients the molar Class II furcation defects were treated with a GTR procedure using the resorbable synthetic material (experimental), and 20 patients received a mucoperiosteal flap debridement procedure without barrier placement (control). Probing depth and attachment level measurements were taken immediately before surgery, at 6 weeks, and 2, 3, 4, 5, and 6 months after surgery. All areas healed uneventfully. Comparison of clinical attachment level measurements indicated significantly greater gain of attachment at sites receiving barriers. Fifteen of 20 Class II furcations in the synthetic barrier group, but only one of 20 in the control group, were converted to Class I defects. Barriers were still clinically detectable at 4 weeks, but were absent at 6 weeks. The synthetic barriers enhanced gain of clinical attachment in human Class II furcation defects.

Biological and measurement issues critical to design of gingivitis trials

Chronic plaque-induced gingivitis is usually of little consequence, thus the concern about prevention and treatment must stem from the belief that preexisting gingivitis is necessary for periodontitis to develop. When clinical signs of gingivitis are present, an inflammatory infiltrate can be found upon histological evaluation. When clinical signs are absent, however, significant inflammation may still be present within the gingival tissues. Therefore, multiple clinical evaluations should be made, with special attention given to the visually inaccessible midinterdental area. The "gold standard" for evaluation of gingivitis is histological evaluation and other measurements should be evaluated against this standard. The significance of clinical severity measurements of gingivitis is not well-understood relative to onset of periodontitis; therefore, it is suggested that consideration be given to gingival evaluations based on the presence or absence of clinical signs of inflammation. Furthermore, equivalency and superiority of antigingivitis agents or devices should be predicated, at least in part, on their ability to prevent the onset of periodontitis.

Periodontal disease activity: a critical assessment

Review of investigations using longitudinal probing and radiographic assessments indicate that the prevalence, magnitude, rate, and temporal patterns of periodontal destruction as well as the ability of clinical and laboratory tests to detect and predict loss of clinical attachment need further investigation. These unresolved issues are discussed and their impact on the practice of periodontics is examined.

Effects of personal oral hygiene and subgingival scaling on bleeding interdental gingiva

The aim of this study was to determine the effects of personal oral hygiene and subgingival scaling on bleeding interdental gingiva. The Eastman Interdental Bleeding Index (EIBI) was used to clinically evaluate interdental gingival status. Forty-seven bleeding interdental sites in 47 patients were divided into three groups. Sites in Group I bled on stimulation with wooden interdental cleaners. Groups II and III initially bled but were converted to nonbleeding with oral hygiene alone or oral hygiene combined with subgingival scaling, respectively. Interdental gingival biopsies were obtained and subjected to morphometric analysis to compare the three groups. The findings from this study indicated that: (A) personal oral hygiene reduced the magnitude and extent of the interdental inflammatory lesion; (B) subgingival scaling plus oral hygiene decreased the interdental inflammatory lesion to a greater extent than oral hygiene alone; (C) significant repair of the interdental lesion occurred within four weeks; and (D) the EIBI was an effective method for monitoring the effects of therapy directed towards resolution of the interdental inflammatory lesion.

Associations between bleeding and visual signs of interdental gingival inflammation

Interdental gingival tissues are designated inflamed on the basis of their color and bleeding after stimulation. Gingival bleeding was previously shown in histological studies to indicate the presence of inflammatory lesions. The present study was undertaken to determine associations between bleeding and visual signs of interdental gingival inflammation. Each interdental site in 82 males, aged 18 to 30, was evaluated for the presence or absence of visual signs of inflammation. The interdental sites on one side of the mouth were evaluated for bleeding tendency using the Papilla Bleeding Index (PBI), while the other half was evaluated using the Eastman Interdental Bleeding Index (EIBI). The percentage of inflamed areas detected with the EIBI and visual method was similar and significantly higher than with the PBI. When the visually noninflamed sites were examined, 38.5% of these areas bled, indicating that interdental inflammatory lesions existed in the absence of visual signs of inflammation. Of the sites that bled but were visually noninflamed, 33.1% were detected using the PBI, while 66.9% were detected using the EIBI. The Eastman Interdental Bleeding Index was a more reliable clinical indicator for detecting interdental inflammatory lesions than the Papilla Bleeding Index.

Effect of personal oral hygiene on bleeding interdental gingiva. Histologic changes

A previous study demonstrated that the combination of subgingival scaling and improved oral hygiene resulted in a reduction of clinical and histological signs of interdental gingival inflammation, changes that were associated with a cessation of interdental gingival bleeding. The present study compared, histologically, the interdental tissues of bleeding sites with sites that initially bled but had been converted to nonbleeding by an oral hygiene program alone. Morphometric analysis of interdental gingiva demonstrated that conversion from bleeding to nonbleeding was associated with a significant reduction in the inflamed connective tissue component. This study showed that an oral hygiene program consisting of toothbrushing and interdental cleaning could significantly reduce interdental inflammation, and that bleeding determinations monitored the effects of this therapy.

Cell populations associated with conversion from bleeding to nonbleeding gingiva

The purpose of this study was to observe changes in cell populations of the interdental gingival tissue, which accompanied the conversion of a bleeding to a nonbleeding state induced by scaling and improved oral hygiene. Fifteen bleeding and 18 stopped-bleeding interproximal gingival biopsies were obtained from 33 patients and processed for light microscopic evaluation. The morphometric analysis of eight connective tissue components revealed that the percentage volume density of all inflammatory cells decreased, and the percentage of fibroblasts and collagen increased, when the gingiva changed from a bleeding to a nonbleeding state. Furthermore, the inflammatory cell infiltrate in bleeding and stopped-bleeding specimens was dominated by mononuclear cells of the lymphocyte/macrophage/monocyte group, while plasma cells and polymorphonuclear leukocytes comprised only a small fraction of the inflammatory cells present. Significant repair of gingival connective tissue had occurred in the stopped-bleeding specimens.

Sequence analysis of the Alcaligenes eutrophus chromosomally encoded ribulose bisphosphate carboxylase large and small subunit genes and their gene products

The nucleotide sequence of the chromosomally encoded ribulose bisphosphate carboxylase/oxygenase (RuBPCase) large (rbcL) and small (rbcS) subunit genes of the hydrogen bacterium Alcaligenes eutrophus ATCC 17707 was determined. We found that the two coding regions are separated by a 47-base-pair intergenic region, and both genes are preceded by plausible ribosome-binding sites. Cotranscription of the rbcL and rbcS genes has been demonstrated previously. The rbcL and rbcS genes encode polypeptides of 487 and 135 amino acids, respectively. Both genes exhibited similar codon usage which was highly biased and different from that of other organisms. The N-terminal amino acid sequence of both subunit proteins was determined by Edman degradation. No processing of the rbcS protein was detected, while the rbcL protein underwent a posttranslational loss of formylmethionyl. The A. eutrophus rbcL and rbcS proteins exhibited 56.8 to 58.3% and 35.6 to 38.5% amino acid sequence homology, respectively, with the corresponding proteins from cyanobacteria, eucaryotic algae, and plants. The A. eutrophus and Rhodospirillum rubrum rbcL proteins were only about 32% homologous. The N- and C-terminal sequences of both the rbcL and the rbcS proteins were among the most divergent regions. Known or proposed active site residues in other rbcL proteins, including Lys, His, Arg, and Asp residues, were conserved in the A. eutrophus enzyme. The A. eutrophus rbcS protein, like those of cyanobacteria, lacks a 12-residue internal sequence that is found in plant RuBPCase. Comparison of hydropathy profiles and secondary structure predictions by the method described by Chou and Fasman (P. Y. Chou and G. D. Fasman, Adv. Enzymol. 47:45-148, 1978) revealed striking similarities between A. eutrophus RuBPCase and other hexadecameric enzymes. This suggests that folding of the polypeptide chains is similar. The observed sequence homologies were consistent with the notion that both the rbcL and rbcS genes of the chemoautotroph A. eutrophus and the thus far characterized rbc genes of photosynthetic organisms have a common origin. This suggests that both subunit genes have a very ancient origin. The role of quaternary structure as a determinant of the rate of accepted amino acid substitution was examined. It is proposed that the sequence of the dimeric R. rubrum RuBPCase may be less conserved because there are fewer structural constraints for this RuBPCase than there are for hexadecameric enzymes.

Interproximal gingival inflammation related to the conversion of a bleeding to a nonbleeding state

Elimination of gingival bleeding has been related to a reduction in inflammation; however, histologic data are not available to support this association. The purpose of this study was to characterize the histology of interproximal gingiva that was converted from a bleeding to a nonbleeding state. An interproximal gingival biopsy was obtained from each of 32 patients, 15 of whom bled upon stimulation with a soft wooden interdental cleaner. The remaining 17 biopsies were obtained from sites which initially bled, but were converted to nonbleeding by scaling and interproximal plaque control. Specimens were processed for light microscopic evaluation and subjected to a morphometric analysis for various tissue components. Data from bleeding and "stopped bleeding" specimens were compared using analysis of covariance. The results indicated that "stopped bleeding" specimens had significantly less inflamed connective tissue. It was concluded that the conversion of a bleeding to a nonbleeding state corresponds with a histological reduction in the magnitude of the interproximal inflammatory lesion and provides a rationale, therefore, for the use of bleeding to monitor the effects of therapeutic methods.

[Congenital superior radioulnar synostoses. A study of 43 cases]

Superior radioulnar synostosis is a rare abnormality which frequently gives rise to functional disability. Its pattern of inheritance is uncertain. We have studied 29 children, 18 boys and 11 girls, who had a total of 43 such synostoses. Twenty children had significant functional disability. Fourteen required operation, 10 undergoing a Judet's osteotomy and 4 osteotomy of the lower end of the radius. The dominant hand was placed in the position of function, and the other in 30-40 degrees of supination. The osteotomies were secured by pins and supported in a plaster splint. Use of the forearm and hand was improved in all cases. Operation is best carried out between the ages of 4 and 10, and a useful functional improvement can be expected.

Histologic comparisons of interproximal gingival tissues related to the presence or absence of bleeding

Interproximal gingival tissues were compared histologically relative to the presence or absence of bleeding after stimulation with a wooden interdental cleaner. Fifteen bleeding and 15 nonbleeding interproximal gingival biopsy specimens were obtained from 30 patients and processed for light microscopic evaluation. Morphometric analysis of tissue components revealed that bleeding areas had a significantly greater per cent of inflamed connective tissue. The inflammatory lesion in the bleeding specimens was primarily in the midinterproximal area. From a diagnostic standpoint, this information provides a rationale for the use of bleeding to detect inflammatory lesions in the midinterproximal region.

Periodontal response after tooth movement into intrabony defects

The present study was undertaken since conflicting evidence exists regarding the effect of such tooth movement on levels of connective tissue attachment. Localized intrabony pockets were produced around isolated incisors in four rhesus monkeys. The root surfaces were planned to the level of the bone at the base of the angular bony defects. An oral hygiene regime was begun and continued for the remainder of the study. The experimental teeth were moved orthodontically into, and through, the original area of the intrabony defect. Two months after cessation of active tooth movement, block specimens were removed for histologic analysis. Control specimens comprised those teeth with induced periodontal defects, but without tooth movement. In specimens not subjected to tooth movement, angular bony defects were present and epithelium lined the root surface to the apical extent of instrumentation. The alveolar bone adjacent to the orthodontically moved teeth no longer had angular defect morphology. On the pressure side, epithelium lined the root surface, was interposed between root surface and bone and terminated at the apical limit of root instrumentation. On the tension side, the crest of the bone was located apical to the level of root planing, and epithelium lined the instrumented portion of the root surface. It was concluded that orthodontic tooth movement into intrabony periodontal defects was without effect upon the levels of connective tissue attachment.

A periodontal attachment mechanism without alveolar bone. Case report

A 22-year-old black male was referred for periodontal therapy because of radiographic evidence of advanced bone loss associated with the posterior teeth. Clinical examination revealed gingivitis, normal sulcus depths, and minimal loss of clinical attachment. Complete blood counts, serum chemistry, and neutrophil function were within normal limits. Histological, histochemical and ultrastructural analysis of an extracted tooth revealed no loss of attachment; large areas of the cementum were collagen-poor and, ultrastructurally, resembled afibrillar cementum. It is proposed that the periodontal attachment mechanism present in this case was associated with a localized failure in normal periodontal development.

Factors influencing periodontal repair and regeneration

The purpose of the present study was to evaluate independently the regeneration capacity of a reduced periodontium, and the potential for new connective tissue attachment to a periodontally exposed root surface. A reduced periodontium was produced around a maxillary central incisor in two Rhesus monkeys using orthodontic elastics. The regeneration capacity of this reduced peridontium was investigated by extracting the periodontally involved tooth and transplanting into the socket the contralateral incisor which had a normal periodontium. The potential for new connective tissue attachment to a periodontally exposed root surface was evaluated by transplanting an exposed root into a normal periodontium. These exposed roots were the incisors extracted from the reduced peridontium. Control specimens were obtained by extracting and reimplanting or transplanting the remaining maxillary and mandibular incisors. Forty days after the experimental procedures, block sections were removed and prepared for histologic analysis. The exposed root surface that had been put into the normal periodontium was lined with epithelium interposed between root surface and alveolar bone. The normal root surface that had been put into the reduced periodontium had connective tissue reattachment in the periodontal ligament and supracrestal regions. Areas of ankylosis and root resorption were present in all specimens, as was new cementum in the periodontal ligament region. The results indicated that root surface alterations, rather than presence of a reduced periodontium, inhibited new connective tissue attachment.

Maintenance of healed periodontal pockets after a single episode of root planing

The present study evaluated the clinical stability of healed periodontal pockets over a 3 month time period to determine whether this time interval is appropriate for periodontal maintenance therapy. The clinical characteristics of 128 pockets (3-7 mm depth) distributed in 10 patients, were monitored immediately before and 4, 8 and 16 weeks after a single episode of subgingival root planing. The clinical parameters measured were: pocket depth and bleeding after probing with 15, 25 and 50 gm and manual probing, gingival margin location, clinical attachment level, and gingival and plaque indices. Oral hygiene instruction and supragingival cleaning were given at each time point. An average aggregated score for each subject and for each parameter was calculated at each time point. A repeated measure all within analysis of variance was done, and the Tukey multiple range test was used to assess the significance of differences among and between the means. The significant decreases in plaque, gingival and bleeding indices, and pocket depth as well as the significant gingival recession and gain of clinical attachment which were present at the 4 week point were maintained at 8 and 16 weeks after root planing. It was concluded that the favorable clinical changes which occur in periodontal pockets within 1 month after a single episode of subgingival root planing combined with improved oral hygiene can be maintained for an additional 3 month time period.

Initial healing of periodontal pockets after a single episode of root planing monitored by controlled probing forces

THE PURPOSE OF the present study was to evaluate, using controlled probing forces, the response of periodontal pockets to a single episode of root planing. The clinical characteristics of 128 pockets (3-7 mm depth) distributed in ten subjects, were monitored immediately before and 1, 2, 3, and 4 weeks after a single episode of subgingival root planing. The clinical parameters measured were: pocket depth and bleeding after probing with 15 gm, 25 gm, 50 gm of controlled probing force and manual probing, gingival margin location, loss of attachment, gingival and plaque indices. Oral hygiene instruction and supragingival prophylaxis were given at each time point. An average aggregated score for each subject for each parameter was calculated at each time point. A repeated measure all-within analysis of variance was done, and the Tukey multiple range test was used to assess the significance of differences among and between the means. Plaque and gingival indices decreased significantly after 1 week. Significant pocket depth reduction (initial) occurred 1 week after root planing, and reduced further (secondary) at 3 weeks. Initial pocket reduction was associated with significant gingival recession, whereas secondary pocket reduction was associated with significant gain of clinical attachment. Bleeding upon probing was virtually absent after 3 weeks. All probing changes were detected more consistently using controlled insertion pressures. It was concluded that substantial reduction in pocket depth occurs within 3 weeks after a single episode of root planing owing to initial gingival recession and secondary gain in clinical attachment.

Relationships between epithelium and connective tissue in inflamed gingiva

Since chronic inflammation has been associated with degenerative and proliferative responses in connective tissue and epithelium, it was decided to investigate quantitatively the proportions of epithelium and connective tissue in inflamed gingiva. Forty-five midfacial gingival sites were assessed prior to biopsy for the presence or absence of bleeding after probing using a controlled insertion force fo 25 g. In order to delineate the corresponding area for histologic analysis, a reference incision was made on the facial surface of the gingiva which demarcated the depth and mesio-distal extent of the area probed. Step-serial bucco-lingual sections were morphometrically analyzed to determine the percentages of epithelium, inflamed, and noninflamed connective tissues coronal to the reference incision. The data was compared with respect to the presence or absence of bleeding after probing. Specimens which bled after probing had significantly less epithelium and more connective tissue. The increase in overall connective tissue was due to a significant increase in the inflamed component, and it appeared that the decrease in epithelium corresponded to the increase in inflamed connective tissue. The findings of diminished epithelium overlying inflamed connective tissue reinforces the concept that connective tissue status is important for determining structure and function of epithelium.

Depth of periodontal probe penetration related to clinical and histologic signs of gingival inflammation

The purpose of this study was to determine if the depth of periodontal probe penetration into the gingival sulcus was related to bleeding after probing with a standardized force, visual signs of gingival inflammation, and histological parameters of gingival inflammation. Sixty midfacial gingival sites in 26 persons were evaluated for presence or absence of visible inflammation and bleeding after probing using a controlled insertion pressure of 25 gm. In order to delineate the area for histologic analysis, a reference incision was made on the facial surface of the gingiva which corresponded to the depth and mesio-distal extent of the area probed and evaluated for visual signs of inflammation. Gingival biopsy specimens were histometrically analyzed to determine the depth of probe penetration and percentage of inflamed connective tissue. Statistical analysis of the data demonstrated that probe penetration was significantly greater in the presence of visible inflammation, but not with bleeding after probing. Furthermore, only a weak correlation existed between depth of probe penetration and percentage of inflamed connective tissue adjacent to the area probed.

Histologic characteristics associated with bleeding after probing and visual signs of inflammation

This study was designed to characterize histologically the gingival lesion associated with visual signs of inflammation and bleeding after probing. Sixty midfacial gingival sites in 26 persons were evaluated for visual presence of absence of inflammation and bleeding after probing using a controlled insertion pressure of 25 gm. In order to delineate the area for histologic analysis, a reference incision was made on the facial surface of the gingiva which corresponded to the depth and mesio-distal extent of the area probed and evaluated for signs of inflammation. Gingival biopsy specimens were morphometrically analyzed to determine the percentages of cell rich--collagen poor connective tissue and blood vessel lumens. Histometric data were grouped and compared with respect to the presence or absence of inflammation and bleeding. Specimens associated visually with inflammation had significantly greater percentages of both cell rich--collagen poor connective tissue and blood vessel lumens. Bleeding upon probing was associated with a significantly greater percentage of cell rich--collagen poor connective tissue without an increase of blood vessel lumens. It was concluded that both observed signs of inflammation and bleeding after probing can be used to detect inflammatory lesions in the gingiva. However, in areas inaccessible for evaluation of inflammation, bleeding determinations using controlled insertion pressures provided an objective diagnostic method for detecting the presence of an inflammatory lesion.