[Anterior shoulder instability with Hill-Sachs on-track. Bankart or Bankart-remplissage?]

INTRODUCTION

in patients with anterior glenohumeral (GH) instability together with an off-track or engaging Hill-Sachs (HS) defect, Bankart-remplissage (B-R) surgery reduces the recurrence rate when compared to Bankart (B) surgery alone. There is controversy regarding whether the recurrence rate also decreases in patients with on-track or non-engaging Hill-Sachs defects.

OBJECTIVE

to compare the recurrence rate and clinical evolution of patients with anterior glenohumeral instability with 'on-track' Hill-Sachs defect treated with either B or B-R surgery.

MATERIAL AND METHODS

non-randomized, retrospective, single-center cohort study of patients with anterior glenohumeral instability and on-track Hill-Sachs defect, operated between January 2010 and December 2018. Patients operated with B versus B-R were compared. Recurrence, complications and re-operation were recorded. In addition, VAS, SSV, WOSI and qDASH scores were obtained and compared in both groups.

RESULTS

of the 105 patients who met the inclusion criteria, 78 (74.3%) patients had a complete follow-up (52 B and 26 B-R, 4.3 years median follow-up). There was a higher recurrence rate in group B compared to B-R, with this difference not reaching statistical significance (17.3% vs 7.7%, p = 0.21). There were no significant differences in residual pain, feeling of instability, complications or VAS, qDASH, SSV or WOSI scores between both groups. In the subgroup analysis, patients who practiced contact sports and were operated with B showed higher recurrence rates (24.1% vs 0%, p = 0.08) and complications (41.4% vs 18.2%, p = 0.16) when compared to B + R, although these differences were not significant.

CONCLUSION

there were no significant differences in recurrence rates and functional evolution between patients with anterior glenohumeral instability operated with B or B-R surgery. Comparative, prospective studies should be performed to establish definitive recommendations.

Health related quality of life in celiac children and adolescents

INTRODUCTION

The lifelong gluten-free diet (GFD) is the treatment of celiac disease (CD). Being a restrictive diet, it limits daily life and can impact on the health-related quality of life (HRQoL). Our objective was to assess HRQoL of celiac patients on a GFD, the concordance between patients - caregivers, and to compare the local results with international data.

PATIENTS AND METHOD

Patients aged 8-18 years on a GFD for >6months (37 dyads) were evaluated. The "Celiac Disease Dutch Questionnaire" (CDDUX) was applied, which evaluates in two questionnaires (one applied to the child and another one to the caregiver/parent), three areas: i) having CD, ii) communication with others, and iii) the diet. Reliability, dimensionality, and internal consistency were assessed using the Cronbach coefficient.

RESULTS

More than 50% of patients and caregivers reported "well/very well" on sub-scales "having CD" and "GFD"; "communication" showed high percentages of "bad/very bad". Although there were no significant differences in HRQoL (global and subscale) perceived by patients and caregivers, there were when analyzing the answers of caregivers, who assigned better scores to boys (p=0.022) and to patients maintaining a non-strict GFD (p=0.049). Concordance between patients and caregivers was 39.2%.

DISCUSSION

HRQoL of the assessed celiac children was satisfactory, among the best repor ted in Latin America. "Having CD" and the need for a "GFD" have less influence on HRQoL than "communication" with others about the disease. The concordance found suggests that the caregivers' perception does not necessarily reflect what patients perceive.

Living with Gluten and Other Food Intolerances: Self-Reported Diagnoses and Management

People suffering from a food intolerance (FI) tend to initiate restrictive diets such as a gluten-free diet (GFD), to alleviate their symptoms. To learn about how people live with these problems in daily life (independent of their medical diagnoses), 1203 participants answered a previously validated questionnaire and were divided into: G1 (those self-reporting symptoms after gluten consumption) and G2 (those informing no discomfort after gluten consumption). Self-reported clinical characteristics, diagnoses and diets followed were registered. Twenty nine percent referred some FI (8.5% in G1). In G1, self-reported diagnoses were more frequent (p < 0.0001), including a high proportion of eating and mood disorders. Diagnoses were reported to be given by a physician, but GFD was indicated by professional and nonprofessional persons. In G2, despite declaring no symptoms after gluten consumption, 11.1% followed a GFD. The most frequent answer in both groups was that GFD was followed “to care for my health”, suggesting that some celiac patients do not acknowledge it as treatment. Conclusion: close to one third of the population report suffering from some FI. Those perceiving themselves as gluten intolerant report more diseases (p < 0.0001). A GFD is followed by ~11% of those declaring no symptoms after gluten ingestion. This diet is perceived as a healthy eating option.

Changes in Age at Diagnosis and Nutritional Course of Celiac Disease in the Last Two Decades

The frequency of celiac disease (CD) has increased along time, with relevant changes reported in geographical variations, clinical presentation and nutritional repercussions. In recent years, some celiac patients are presenting overweight/obesity, but it is unclear how frequent this is and to what extent undernutrition remains a concern. This is relevant because CD tends to be overlooked in overweight patients. With this in mind, we assessed age at diagnosis, clinical characteristics and nutritional status of 155 celiac patients diagnosed between 1994–2017 in four pediatric hospitals in Santiago, Chile. Since 2003, the number of patients diagnosed has increased (p < 0.0033), coinciding with antitransglutaminase and antiendomysial antibodies becoming available to public health systems. In 2000, 4.5% of patients were asymptomatic at diagnosis, suggesting that active search is not routinely applied. Gastrointestinal symptoms plus failure to thrive were significantly more frequent under 2 years (p = 0.0001). Nutritional status has improved at diagnosis and during follow up, but undernutrition remains more frequent in children <2 and <5 years (p < 0.002 and p < 0.0036, respectively). Overweight at diagnosis was reported in 2002 and obesity in 2010. After initiating treatment, since 2010, patients changing from undernourishment to overweight has sometimes been observed after only 6 months on a gluten-free diet.

Corrigendum: Helicobacter pylori cagA+ Is Associated with Milder Duodenal Histological Changes in Chilean Celiac Patients

[This corrects the article on p. 376 in vol. 7, PMID: 28879170.].

Helicobacter pylori cagA+ Is Associated with Milder Duodenal Histological Changes in Chilean Celiac Patients

HIGHLIGHTS

What is already known about this subject?

Celiac disease (CD) has a high clinical and histological diversity and the mechanisms underlying this phenomenon remain elusive.

H. pylori is a bacterium that chronically infect gastric and duodenal mucosa activating both a Th1/Th17 and T-reg pathways.

The role of H. pylori (and the effect of their virulence factors) in CD have not yet completely elucidated.

What are the new findings?

cagA+ H. pylori strains are associated to milder histological damage in infected CD patients.

In active-CD patients the presence of cagA+ H. pylori is associated to an increase in T-reg markers, contrasting with a downregulation in cagA+ infected potential-CD individuals.

How might it impact on clinical practice in the foreseeable future?

The identification of microbiological factors that could modulate inflammation and clinical expression of CD may be used in the future as preventive strategies or as supplementary treatment in patients that cannot achieve complete remission, contributing to the better care of these patients.

Background: Mechanisms underlying the high clinical and histological diversity of celiac disease (CD) remain elusive. Helicobacter pylori (Hp) chronically infects gastric and duodenal mucosa and has been associated with protection against some immune-mediated conditions, but its role (specifically of cagA+ strains) in CD is unclear.

Objective: To assess the relationship between gastric Hp infection (cagA+ strains) and duodenal histological damage in patients with CD.

Design: Case-control study including patients with active-CD, potential-CD and non-celiac individuals. Clinical presentation, HLA genotype, Hp/cagA gene detection in gastric mucosa, duodenal histology, Foxp3 positive cells and TGF-β expression in duodenal lamina propria were analyzed.

Results: We recruited 116 patients, 29 active-CD, 37 potential-CD, and 50 non-CD controls. Hp detection was similar in the three groups (~30–40%), but cagA+ strains were more common in infected potential-CD than in active-CD (10/11 vs. 4/10; p = 0.020) and non-CD (10/20; p = 0.025). Among active-CD patients, Foxp3 positivity was significantly higher in subjects with cagA+ Hp+ compared to cagA- Hp+ (p < 0.01) and Hp- (p < 0.01). In cagA+ Hp+ individuals, Foxp3 positivity was also higher comparing active- to potential-CD (p < 0.01). TGF-β expression in duodenum was similar in active-CD with cagA+ Hp+ compared to Hp- and was significantly downregulated in cagA+ potential-CD subjects compared to other groups.

Conclusion: Hp infection rates were similar among individuals with/without CD, but infection with cagA+ strains was associated with milder histological damage in celiac patients infected by Hp, and in active-CD cases with higher expression of T-reg markers. Results suggest that infection by cagA+ Hp may be protective for CD progression, or conversely, that these strains are prone to colonize intestinal mucosa with less severe damage.

[Active search of celiac disease among first degree relatives of known celiac patients]

BACKGROUND

Active search of celiac disease (CD) among risk groups has significantly increased the scope of known clinical variants.

AIM

To measure the frequency and clinical characteristics of CD among first degree relatives (FDR) of known celiac cases.

MATERIAL AND METHODS

Between January 2012-August 2013, 37 patients with celiac disease brought 113 FDR for assessment. Their clinical data was recorded and a blood sample was obtained to measure serum Immunoglobulin A (IgA) levels, anti-transglutaminase (tTG) and anti-endomisial (EMA) antibodies. Cases with positive serology were advised to have an intestinal biopsy.

RESULTS

Fourteen relatives (12.4%) had positive serological results and none had IgA deficiency. Among IgA-tTG (-) cases, measurement of IgA/IgG-tTG identified an additional case. Two of the 14 relatives were EMA positive. All 14 cases were advised to have an intestinal biopsy, but only 6 accepted the procedure. In two, the intestinal lesion was classified Marsh ≥ 2 and active CD was diagnosed. Histology in the remaining four was Marsh 0/1 and were diagnosed potential CD, remaining under control, without gluten free diet.

CONCLUSIONS

Serological prevalence of CD among first degree relatives of known celiac cases was 15 fold greater than in THE general Chilean population, strongly supporting the idea of implementing active search to customary clinical practice. Determination of IgA/IgG-tTG may be useful to improve the yield of active search. Intestinal biopsies were crucial to differentiate active classic CD from potential CD.

FokI polymorphism in vitamin D receptor gene: Differential expression of TNFα in peripheral mononuclear cells of type 2 diabetic subjects

INTRODUCTION

FokI polymorphism has been associated with obesity and type 2 diabetes (T2D) in some populations.

OBJECTIVE

To investigate the frequencies of a genetic polymorphism of Vitamin D receptor (FokI) in patients with T2D and control subjects and investigate the role of 1,25(OH)2D3 in the expression of pro-inflammatory markers in peripheral blood mononuclear cells (PBMCs).

METHODS

The case-control study was conducted in 160 patients with T2D and 160 control subjects, men and women (30-74 years old). The genotype and allele frequency of FokI polymorphisms were determined in these subjects. Subsequently a subgroup of 40 subjects was included from which PBMCs were removed. In vitro, the culture medium was supplemented with two different concentrations of 1,25(OH)2D3(10- 8 M and 10- 10 M). The expression profiles of TNFα and mRNA were analysed by qPCR, and GAPDH and β-actin were used as housekeeping genes.

RESULTS

The control subjects have an increased frequency of the FF genotype. In subjects with T2D, the ff genotype was associated with higher HOMA-IR values than individuals with genotype Ff (p = 0.021). In vitro study in PBMCs showed differential expression of TNFα mRNA by FokI genotype, with a lower expression of this marker of inflammation in FF genotype subjects at a concentration of 10- 8 M of 1,25(OH)2D3.

CONCLUSION

Our data suggest that VDR FokI polymorphism is associated with T2D, and the genotypes Ff and ff of this variant show a reduced response or resistance to the anti-inflammatory action of VitD, which could indicate a functional role of FokI polymorphism of VDR.

Gingival wound healing: an essential response disturbed by aging?

Gingival wound healing comprises a series of sequential responses that allow the closure of breaches in the masticatory mucosa. This process is of critical importance to prevent the invasion of microbes or other agents into tissues, avoiding the establishment of a chronic infection. Wound healing may also play an important role during cell and tissue reaction to long-term injury, as it may occur during inflammatory responses and cancer. Recent experimental data have shown that gingival wound healing is severely affected by the aging process. These defects may alter distinct phases of the wound-healing process, including epithelial migration, granulation tissue formation, and tissue remodeling. The cellular and molecular defects that may explain these deficiencies include several biological responses such as an increased inflammatory response, altered integrin signaling, reduced growth factor activity, decreased cell proliferation, diminished angiogenesis, reduced collagen synthesis, augmented collagen remodeling, and deterioration of the proliferative and differentiation potential of stem cells. In this review, we explore the cellular and molecular basis of these defects and their possible clinical implications.

High concentrations of anti-caspase-8 antibodies in Chilean patients with type 1 diabetes

INTRODUCTION

Deregulation of apoptosis across the Fas-FasL pathway is an increasingly relevant phenomenon in the pathogenic mechanisms associated with autoimmune diseases. Caspase-8 initiates the activation of the apoptotic process and interacts directly with Fas in the membrane of the T lymphocyte.

OBJECTIVES

To standardize an Elisa essay to measure the concentration of anti-caspase-8 antibodies in plasma of Type 1 Diabetes (T1D) patients and analyze their possible distribution and association with characteristics of the disease.

METHODS AND SUBJECTS

124 patients newly diagnosed with T1D and 132 controls: children and youngsters. ELISA test was standardized to detect anti-caspase-8 antibodies in plasma. It correlated the concentration of this antibody with classical markers of autoimmunity as anti-IA-2 and anti-GAD65, and the clinical characteristics at onset of diabetes mellitus. The statistical analysis was performed using logistic regression.

RESULTS

Patients with T1D showed a higher concentration of anti-caspase-8 antibodies regarding the controls (87.5 ng/ml versus 24.3 ng/ml, p < 0.0001, values expressed as median). The proportion of patients with T1D and high concentrations of anti-caspase-8 (percentile 50-75) was significantly different from the control group (p < 0.0001). Anti-caspase-8 showed a strong association with positive anti-GAD65 (OR = 3.48, p < 0.035) and ketoacidosis (OR = 10.74, p < 0.0001) events, with glycemia and age at diagnosis as contributing variables.

CONCLUSION

This is the first report in the literature of levels of anti-caspase-8 antibodies in T1D through ELISA. The high concentration in patients with T1D, and its strong correlation with anti-GAD65 auto-antibodies, suggests a potential role of anti-caspase-8 auto-antibodies as surrogate marker autoimmunity in T1D patients.

[Programmed cell death 1 (PDCD1) gene polymorphisms and type 1 diabetes in Chilean children]

BACKGROUND

Programmed cell death 1 (PDCD-1) immune-receptor is a key element in the negative regulation of peripheral tolerance in T cells. Several polymorphisms of this gene have been described and it is linked with susceptibility to autoimmune diseases like Lupus and Multiple Sclerosis.

AIM

To analyze four gene polymorphisms of PDCD-1 gene and explore its possible contribution as a susceptibility gene for type 1 diabetes (T1D).

PATIENTS AND METHODS

We analyzed 160 cases with T1D of recent diagnosis aged 9.5 +/- 3.3 years and 160 control children aged 10.7 +/- 3.1 years. Four genetic variants of PDCD-1 gene were studied (PD1.2; PD1.5; PD1.6 and PD1.9) by polymerase chain reaction and restriction enzymes. Autoantibodies GAD65 and anti-IA-2 were also measured in all studied children. The comparison of allelic and genotypic frequency and consistency with respect to Hardy-Weinberg equilibrium test were analyzed using Chi-square and Fisher exact test.

RESULTS

No differences between cases and controls were observed for PDCD1.2; PDCD1.5 and PDCD1.9 polymorphisms. PDCD1.6 polymorphism (carriers of allele A) had a higher frequency in the control group (0.794 versus 0.644, p < 0.017). There was no particular association of these polymorphisms with anti- GAD65 and anti-IA-2 antibodies among patients with T1D.

CONCLUSIONS

Only PDCD1.6 polymorphism showed differences between T1D cases and controls. Possibly, none of these genetic variants of PDCD1 has a relevant role as a marker for T1D in the Chilean population.

[Plasma levels of interleukin-1beta, interleukin-2 and interleukin-4 in recently diagnosed type 1 diabetic children and their association with beta-pancreatic autoantibodies]

BACKGROUND

Type 1 diabetes is an organ specific autoimmune disease whose incidence is increasing worldwide. A functional imbalance in cytokine production resulting in dominance of T helper (Th1) over Th2-type response has been suggested to play a critical role in the pathogenesis of type 1 diabetes.

AIM

To measure serum concentrations of interleukin (IL)-1beta, IL-2 and IL-4 in children with recently diagnosed type 1 diabetes and to evaluate the autoimmune response measuring glutamic acid decarboxylase (GAD65) and tyrosine phosphatase like (IA-2) autoantibodies.

PATIENTS AND METHODS

120 diabetic children and 118 age and gender matched control children, were recruited for this study. Circulating levels of IL-1beta IL-2 and IL-4 were measured by ELISA. GAD65 and IA-2 were measured by RIA.

RESULTS

Circulating levels of IL-1beta were elevated in type 1 diabetic children as compared to the control group (9.3 +/- 7.3 and 4.9 +/- 3.8 pg/ml respectively, p=0.01). Serum concentration of IL-2 was also higher in diabetic patients (19.8 +/- 13.1 and 113 +/- 9.1 pg/ml respectively, p=0.01). No differences in serum IL-4 were observed between diabetics and control. Diabetic children with one or two positive autoantibodies (IA-2 and/or GAD65) had significantly higher levels of IL-1beta and IL-2 and lower levels of IL-4 than diabetic children without positive autoantibodies. High concentrations of IL-1beta were associated with an early onset of the disease.

CONCLUSIONS

High levels of IL-1beta and IL-2 were found in diabetic children with recent diagnosis of the disease. Diabetics with positive antibodies against GAD65 and IA-2 had higher levels of IL-1beta and IL-2 and lower levels of IL-4 than their counterparts without positive antibodies.

Duration of breast feeding and bovine serum albumin antibody levels in type 1 diabetes: a case-control study

OBJECTIVE

To compare the levels of bovine serum albumin (BSA) antibodies and their relationship with duration of breast feeding, age of exposure to cow's milk, and human leukocyte antigen (HLA-DQ) genotype in children with and without type 1 diabetes.

METHODS

Serum samples from 143 (0.3-14.7 yr) newly diagnosed children with type 1 diabetes and 107 unrelated control children (0.8-13.5 yr) were evaluated for BSA antibodies. Duration of breast feeding and exposure to cow's milk were recorded on questionnaires. HLA-DQ typing was determined by polymerase chain reaction.

RESULTS

One hundred percent of the diabetic children were positive for BSA antibodies compared to 1.9% for healthy controls (p < 0.001). Diabetic children also had higher levels of immunoglobulin G antibodies than unrelated controls (55.1 vs. 17.8 ng/mL, p < 0.0001). Duration of breast feeding (5.4 vs. 7.6 months, p < 0.02), but not age of exposure to cow's milk (8.3 vs. 9.2 months, p = 0.11), differed between cases and controls. There was no difference in antibody titer by duration of breast feeding or age of exposure to cow's milk in the cases or controls.

CONCLUSION

Higher levels of antibodies to BSA were found in children recently diagnosed with type 1 diabetes compared to the controls, particularly those with high or moderate HLA-DQ genotypes. The BSA profile, however, does not seem to depend on duration of breast feeding or age of exposure to cow's milk in this population.

[Bovine serum albumin (BSA) antibodies in children with recently diagnosed type 1 diabetes with breast feeding and milk exposition]

BACKGROUND

Environmental and genetic factors (viruses, toxins and diet) are involved in the aetiology of type 1 diabetes. Among the dietary factors, the role of breast feeding and exposure to cow's milk proteins deserve special attention.

AIM

To determine the anti-BSA-IgG levels in type 1 diabetic children and to analyse the possible association with breast feeding duration, exposure to cow's milk and beta pancreatic auto-antibodies.

PATIENTS AND METHODS

Blood samples were collected from 161 diabetic children and 144 controls to measure anti-BSA-IgG level, GAD65, IA-2 and ICA autoantibodies. All children answered a questionnaire about dietary habits during infancy.

RESULTS

anti-BSA-IgG was positive (using a cut off point of 25.6 ng/ml) in 98% of diabetic children and 0% of the control population. The length of breast feeding or early exposure to cow's milk did not influence the concentration of anti-BSA-IgG. Positive BSA titers did not increase the beta pancreatic reactivity (ICA+, GAD+, IA2+).

CONCLUSIONS

Our data confirm the high frequency of anti-BSA-IgG among diabetic children. However, a specific role in the immunological process of type 1 diabetes cannot be attributed to this protein.

Experimental study of bone response to a new surface treatment of endosseous titanium implants

This study examines a new surface treatment that uses coarse calcium phosphate, which provides the benefits of surface roughening without introducing any foreign materials that may become imbedded in the implants. It is intended to enhance the use of implants in areas of inferior bone quality and quantity, such as the posterior areas of the maxilla and the mandible. Implants placed in the tibia of rabbits were removed after 16 weeks and examined microscopically. Pore sizes examined under the scanning electron microscope met the conditions described in the literature for successful integration. Optic microscopy revealed evidence of bone apposition over the roughened implant surface comparable to that seen in other surfaces. There was a definite absence of fibrous tissue, demonstrating good-to-excellent bone contact with the Restore Resorbable Blast Media implants (Lifecore Biomedical, Chaska, MN). In addition, it appears that the blasting of resorbable calcium phosphate on the machine titanium surface results in the resorbable blast media surface acting like an inert material. Further studies with a larger sample size are needed to confirm these initial findings.

[Auto-antibody profile and breast feeding in type 1 diabetic patients]

BACKGROUND

Islet cell-specific autoantibodies such as islet cell antibody (ICA), antiinsulin (IAA), anti-glutamic acid decarboxylase (GAD) and anti-tyrosine phosphatase (IA2) can be present in patients with type I diabetes. Breast feeding duration and the early exposure to milk substitutes are environmental factors associated to etiology of type 1 diabetes.

AIM

To study the frequency of the anti-GAD, anti-IA-2 e ICA antibodies in Chilean type 1 diabetic patients and determine the possible modulator effect of the breast feeding.

PATIENTS AND METHODS

One hundred thirty four type 1 diabetic patients, aged one to 15 years old, were studied at the moment of their diagnosis. Patients were classified according to the duration of exclusive breast feeding. IA-2 and GAD were determined by radio immuno assay and ICA by means of indirect immunofluorescence.

RESULTS

Subjects with three months or less and those with more than three months of breast feeding were positive for ICA in 78.8 and 90.6% of cases respectively, for GAD in 75 and 54.6% of cases respectively (p = 0.024) and for IA-2 in 73 and 43.8% of cases respectively (p = 0.001). All three antibodies were positive in 53.9 and 21.8% of children with less or more than three months of breast feeding (p = 0.001).

CONCLUSION

Both IA-2 and GAD antibodies are less frequently positive in type 1 diabetic patients who have been breast fed for more than three months. These findings suggest a possible attenuating role of exclusive breast feeding on pancreatic aggression events in patients with type 1 diabetes.

Immunohistochemical and ultrastructural evaluation of the effects of phosphoric acid etching on dentin proteoglycans

It has been reported that phosphoric acid (PA) produces structural and molecular alterations in dentin collagen fibrils; however, no relevant information exists on the influence of etching with PA on dentin non-collagenous macromolecules. The present study investigated, by immunohistochemistry and ultrastructural histochemistry, the behavior of dentin proteoglycans (PG) after etching human dentin samples with 35% PA gel (thickened with colloidal silica) or with a 35% PA liquid for 15, 30 and 120 s. Immunolabeling with a mouse monoclonal anti-chondroitin sulfate antibody demonstrated that glycosaminoglycans (GAG) were preserved within dentinal tubules opened to the surface after etching with PA gel. In addition, the cationic tracer polyethyleneimine, used for the ultramicroscopic localization of PG anionic sites, revealed that treatment of dentin samples with PA gel preserved the polyanionic peritubular PG in the etched area. On the other hand, etching with the PA liquid produced loss of peritubular GAG and PG anionic sites in the etched dentin surface. The results obtained indicated that similar concentrations of PA in gel or liquid formulations differently affect the organization of dentin PG. The clinical significance of these in vitro findings and the structural and molecular interactions of dentin PG with adhesive systems are still unknown.

Microscopic and histochemical study of odontoclasts in physiologic resorption of teeth of the polyphyodont lizard, Liolaemus gravenhorsti

Using tartrate-resistant acid phosphatase (TRAP), we examined the cytodifferentiation of odontoclast cells in resorbing areas of dental tissues during the replacement of teeth in a polyphyodont lizard, Liolaemus gravenhorsti. We also report, by means of Lectin-HRP histochemistry, the distribution pattern of some specific sugar residues of TRAPase-positive cells. For detection of TRAPase activity, the azo dye-coupling technique was used. Lectin binding sites were demonstrated by means of specific HRP-lectins. The process of tooth resorption was divided into four stages: 1) preresorption-the wall of the dental pulp is covered with an odontoblast layer, and no TRAP-positive cells are in the dental pulp; 2) early resorption-TRAP-positive multinucleate odontoclasts are present on the dental wall, but the rest of the pulp surface is still covered with an odontoblast layer; 3) later resorption-the entire surface of the pulp chamber is lined with multinucleate odontoclasts; and 4) final resorption-the tooth has been totally resorbed. Odontoclasts are usually detached from the resorbed surface, and show signs of degeneration. Of the six lectins used, PNA, ECA, and UEA-1 bind to multinucleated but not mononuclear cells. All the remaining lectins, BS-1, RCA(120), and LTA showed no binding to any cells of the teeth. The significance of saccharidic moieties such as acetyl-galactosamine, acetyl-glucosamine, and fucose sugar residues is difficult to ascertain. Perhaps these oligosaccharides might be borne on molecules associated with odontoclastic resorption or associated with multinucleation of odontoclasts after attachment to the dentine surface.

Ultracytochemical localization of hydrogen peroxide production by dental plaque bacteria

This study looked for evidence of in vitro hydrogen peroxide (HP) synthesis in human dental plaque, using an ultracytochemical technique that included incubation in a CeCl3-rich medium. Supragingival dental plaque was obtained from periodontally healthy individuals and subgingival dental plaque from human periodontal disease sites. Specificity of the cytochemical reaction was demonstrated using catalase (as HP scavenger). HP production was indicated by an electron-dense precipitate localized at the cell envelope of unidentified gram-positive and gram-negative bacteria in both supra- and subgingival samples. The ultracytochemical reaction localized the HP production primarily to the plasma membrane and periplasmic space.