The molecular basis of spinocerebellar ataxia type 48 caused by a de novo mutation in the ubiquitin ligase CHIP

The spinocerebellar ataxias (SCAs) are a class of incurable diseases characterized by degeneration of the cerebellum that results in movement disorder. Recently, a new heritable form of SCA, spinocerebellar ataxia type 48 (SCA48), was attributed to dominant mutations in STIP1 homology and U box-containing 1 (STUB1); however, little is known about how these mutations cause SCA48. STUB1 encodes for the protein C terminus of Hsc70 interacting protein (CHIP), an E3 ubiquitin ligase. CHIP is known to regulate proteostasis by recruiting chaperones via a N-terminal tetratricopeptide repeat domain and recruiting E2 ubiquitin-conjugating enzymes via a C-terminal U-box domain. These interactions allow CHIP to mediate the ubiquitination of chaperone-bound, misfolded proteins to promote their degradation via the proteasome. Here we have identified a novel, de novo mutation in STUB1 in a patient with SCA48 encoding for an A52G point mutation in the tetratricopeptide repeat domain of CHIP. Utilizing an array of biophysical, biochemical, and cellular assays, we demonstrate that the CHIPA52G point mutant retains E3-ligase activity but has decreased affinity for chaperones. We further show that this mutant decreases cellular fitness in response to certain cellular stressors and induces neurodegeneration in a transgenic Caenorhabditis elegans model of SCA48. Together, our data identify the A52G mutant as a cause of SCA48 and provide molecular insight into how mutations in STUB1 cause SCA48.

Self-reported measures for surveillance of periodontitis

The purpose of this study was to evaluate the performance of self-reported measures in predicting periodontitis in a representative US adult population, based on 2009-2010 National Health and Nutrition Examination Survey (NHANES) data. Self-reported gum health and treatment history, loose teeth, bone loss around teeth, tooth not looking right, and use of dental floss and mouthwash were obtained during in-home interviews and validated against full-mouth clinically assessed periodontitis in 3,743 US adults 30 years and older. All self-reported measures (> 95% item response rates) were associated with periodontitis, and bivariate correlations between responses to these questions were weak, indicating low redundancy. In multivariable logistic regression modeling, the combined effects of demographic measures and responses to 5 self-reported questions in predicting periodontitis of mild or greater severity were 85% sensitive and 58% specific and produced an 'area under the receiver operator characteristic curve' (AUROCC) of 0.81. Four questions were 95% sensitive and 30% specific, with an AUROCC of 0.82 in predicting prevalence of clinical attachment loss ≥ 3 mm at one or more sites. In conclusion, self-reported measures performed well in predicting periodontitis in US adults. Where preferred clinically based surveillance is unattainable, locally adapted variations of these self-reported measures may be a promising alternative for surveillance of periodontitis.

HbA1c during pregnancy: Its relationship to meal related glycaemia and neonatal birth weight in patients with diabetes

OBJECTIVE

Although home blood glucose (HBG) profiles correlate closely with HbA1c, the strength of the relationship during pregnancy is unclear due to physiological changes which can induce subnormal HbA1c levels. We therefore aimed to establish the strength of the association between mean HBG profiles and HbA1c in diabetic pregnancies and whether HbA1c levels and glycaemic variability affects neonatal birth weight (NBW).

STUDY DESIGN

7-point glycaemic profiles performed throughout pregnancy were obtained retrospectively in 94 consecutive patients attending the diabetes antenatal clinic and compared to the corresponding mean HbA1c levels.

RESULTS

There was a significant linear correlation between mean HBG and HbA1c (HbA1c=0.5HBG+3.1, r=0.71, p<0.0001). Multiple regression analysis demonstrated that both pre- and post-prandial HBG levels correlated significantly and independently with HbA1c, correlation coefficients (r) were 0.63 and 0.65, respectively both p<0.0001. Significant correlations were also observed in patients with gestational diabetes (n=67, mean HbA1c=6.11, r=0.67; p<0.0001) and type 1 diabetes (n=18, mean HbA1c=6.75, r=0.64; p=0.004). All meal related HBG measurements showed similar significant correlations with HbA1c (r values pre- and post-breakfast, pre- and post-lunch, pre- and post-tea and pre-bed are 0.56, 0.55, 0.59, 0.55, 0.56, 0.59, 0.51, respectively p<0.0001 for all time points). Post hoc analysis showed that NBW increased with higher levels of HbA1c; NBW (centiles)+/-S.D. for HbA1c <6.5% versus >6.5% was 78.9%+/-29.2 versus 90.2%+/-18.6, p=0.02.

CONCLUSION

Mean HbA1c levels are closely correlated to all meal related glucose measurements during pregnancy. It is therefore a reliable indicator of overall glycaemic control among patients with diabetes during pregnancy.

Investigation of human pharmacoscintigraphic behavior of two tablets and a capsule formulation of a high dose, poorly water soluble/highly permeable drug (efavirenz)

Human pharmacoscintigraphic behavior of two tablets and a capsule formulation of a high dose, poorly water soluble, highly permeable, micronized drug (efavirenz) was investigated. The tablets and capsule, prepared with samarium oxide and neutron activated to produce radioactive samarium-153, were evaluated for their in vivo disintegration and gastrointestinal (GI) transit in healthy subjects under fasted condition. Scintigraphic images were acquired to coincide with blood sampling times to assess the plasma concentration-time profile in relation to in vivo disintegration and GI transit. The mean gastric emptying times were approximately the same for all three formulations. Although in vivo dosage form disintegration was faster for Tablet A as compared to Tablet B and was similar between Tablet A and the capsule, Tablet A showed a slower rate and extent of drug absorption than Tablet B and the capsule. The results of this study eliminated the initial hypothesis that the difference in in vivo performance between the two tablet formulations is due to a different rate of in vivo disintegration and suggest that for this drug the in vivo dissolution rate of the drug from its disintegrated dosage form was a more important factor affecting the rate and extent of drug absorption.

Immunization of Macaca fascicularis against experimental periodontitis using a vaccine containing cysteine proteases purified from Porphyromonas gingivalis

INTRODUCTION

Periodontitis is a common infectious disease to which Porphyromonas gingivalis has been closely linked, in which the attachment tissues of the teeth and their alveolar bone housing are destroyed. We conducted a study to determine if immunization using a purified antigen could alter the onset and progression of the disease.

METHODS

Using the ligature-induced model of periodontitis in Macaca fascicularis, we immunized five animals with cysteine protease purified from P. gingivalis and used an additional five animals as controls. Alveolar bone loss was measured by digital subtraction radiography.

RESULTS

Immunization induced high titers of specific immunoglobuin G serum antibodies that were opsonic. Total bacterial load, levels of P. gingivalis in subgingival plaque and levels of prostaglandin E(2) in gingival crevicular fluid were significantly reduced. Onset and progression of alveolar bone loss was inhibited by approximately 50%. No manifestations of toxicity were observed.

CONCLUSIONS

Immunization using a purified protein antigen from P. gingivalis inhibits alveolar bone destruction in a ligature-induced periodontitis model in M. fascicularis.

Differential chemokine response of fibroblast subtypes to complement C1q

BACKGROUND AND OBJECTIVE

The pathogenesis of periodontitis includes an inappropriate activation of the classical complement cascade (C') with accumulation of inflammatory C' products in fluids and tissues. Our hypothesis is that in vivo the C' product, C1q, may act as a regulatory component of the innate immune response of distinct matrix fibroblasts to the inflammatory environment. This study analyzed the C1q induction of pro-inflammatory cytokine secretion in fibroblast subtypes derived from distinct periodontal tissues, and identified a mechanism of the cell response.

MATERIAL AND METHODS

Primary human gingival fibroblast, periodontal ligament fibroblast, and granulation tissue fibroblast cultures were treated for 24 h with C1q. Protein arrays assessed the secretory profile of constitutive and C1q-inducible pro-inflammatory cytokines, and enzyme-linked immunosorbent assays were used to quantify the kinetics of each inducible cytokine.

RESULTS

Granulation tissue fibroblast cultures were unresponsive to C1q challenge. In contrast, periodontal ligament fibroblasts responded with a release of monocyte chemoattractant protein (MCP)-1, interleukin-6, interleukin-8, and macrophage inflammatory protein (MIP)-1beta higher than the basal level by 8.2-, 7.0-, 3.8-, and 7.2-fold, respectively. Human gingival fibroblast cultures increased secretion of these chemokines by 5.2-, 4.5-, 3.0-, and 9.8-fold, respectively. Inhibitor studies revealed that C1q-inducible release of chemokines by the human gingival fibroblast and periodontal ligament cultures was contingent upon p38 mitogen-activated protein kinase activity.

CONCLUSION

The ability of C1q to stimulate secretion of pro-inflammatory chemokines depends upon which specific fibroblast subtype is involved. Targeting C1q-activated intracellular signaling pathways may be an effective means to inhibit the production of chemokines that promote inflammatory cell infiltration into gingival and periodontal ligament tissues.

Ovine periodontitis as a potential model for periodontal studies. Cross-sectional analysis of clinical, microbiological, and serum immunological parameters

OBJECTIVES

: To investigate infection and host immunity patterns in sheep with naturally occurring "broken-mouth" periodontitis.

MATERIALS AND METHODS

: Eight periodontally healthy (HS) and eight periodontally diseased ewes (PDS) were selected. Subgingival plaque and sera were collected and examined for evidence of human periodontitis-associated pathogens. Serum IgG titers were measured by ELISA to multiple strains of Porphyromonas gingivalis, Bacteroides forsythus, Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum as well as several purified antigens (cysteine proteases, LPS, K, and fimbriae).

RESULTS

: Neither the organism Aa nor antigens to Aa were found in any animal. Most animals were positive for Pg, Bf, and Pi, but DNA probes detected no difference between HS and PDS relative to amounts of pathogens in subgingival plaque. PDS had significantly higher serum IgG titers to all Pg strains, to 50% of Bf strains, to the Pi and Fn strains, and to fimbriae and the two cysteine proteases (p-values ranging from 0.05 to 0.001). Regression analysis demonstrated a significant association between number of teeth lost and serum IgG antibody titers to whole-cell sonicate antigens of P. gingivalis strains (p<0.01) and body weight (p<0.01).

CONCLUSIONS

: The presence of pathogens associated with periodontitis was reflected in differences in serum IgG titers between healthy and diseased sheep. This may have influenced animal body weight and might have systemic health and economic consequences. The data suggest that susceptible and non-susceptible sheep can be identified for periodontal research.

Similarity of the oral microbiota of pre-school children with that of their caregivers in a population-based study

This study evaluated the similarity between the oral microbiota of young children and that of their adult caregivers. Oral samples from children (174 dentate and 18 pre-dentate) aged 6-36 months and their caregivers in Saipan were assayed using a DNA probe assay. Many species including Streptococcus mutans, Streptococcus sobrinus, Actinomyces species, Campylobacter rectus, Fusobacterium nucleatum, Prevotella intermedia, and Porphyromonas gingivalis were detected in dentate and pre-dentate children, whereas Bacteroides forsythus was detected only in dentate children. A higher percentage of children were positive for the detection of an individual species if the caregiver was also positive. There were significant relative risks of species detection between dentate children and their caregivers. By logistic regression, there were significant positive associations between species detection in caregiver and in child, but not between species detection and child age or maternal education level. In conclusion, dental pathogens were detected in young, including pre-dentate, children. The microbial profiles of children were strongly associated with the microbiota of their caregivers.

Treatment outcome for IDDM patients in relation to glutamic acid decarboxylase autoantibodies and serum IgG to periodontal pathogens

BACKGROUND

Patients with insulin-dependent diabetes mellitus (IDDM) have elevated risk for periodontitis (PD) relative to subjects without diabetes. Whether refractory PD in IDDM patients is related to autoimmunity as indicated by serum glutamic acid decarboxylase autoantibody GAD Ab levels or to host bacterial immunity as reflected by serum antibody titers to periodontal pathogens is unknown.

AIMS

To determine if non-surgical periodontal treatment outcome differs between GAD Ab-seropositive and -seronegative IDDM patients by assessing the following parameters: (1) pretreatment serum levels of GAD Ab, (2) pretreatment serum IgG titers to key periodontal pathogens, and (3) changes in periodontal pocket probing depth (PDC) after treatment.

METHODS

Before and two months after periodontal treatment of 11 GAD Ab-seronegative and 7 -seropositive subjects, PDC was assessed and serum GAD Ab and IgG to Porphyromonas gingivalis (Pg), Bacteroides forsythus (BJ), and Actinobacillus actinomycetemcomitans (Aa) were studied using established radioligand precipitation and enzyme-linked immunosorbent assays, respectively.

RESULTS

The PDC decrease was significantly better for GAD Ab-seronegative subjects than for seropositive subjects (median 1.4 mm+/-0.5 s.d. versus 0.5 mm+/-0.3 s.d., p<0.03, Mann-Whitney). GAD Ab levels and PDC were positively correlated (r=+0.71, p<0.05) for sero-positive subjects but were neutral (r=-0.07) for seronegative subjects. Serum IgG to Pg and GAD Ab levels were positively associated (r2=0.42) in seropositive subjects. Logistic regression analysis confirmed that GAD Ab status was the primary discriminator for PDC (p<0.04).

CONCLUSION

Detection of elevated GAD Ab levels in combination with elevated IgG titers to Pg before treatment is indicative of IDDM patients with refractory PD.

The microbiota of young children from tooth and tongue samples

This study determined the frequency with which 38 microbial species were detected in 171 randomly selected children from 6 to 36 months of age. Children were sampled and dental caries measured. Oral samples were assayed by means of a checkerboard DNA probe assay. The detection frequencies from tongue samples in children under 18 mos were: S. mutans 70%, S. sobrinus 72%, P. gingivalis 23%, B. forsythus 11%, and A. actinomycetemcomitans 30%, with similar detection frequencies in children over 18 mos. Thus, S. mutans and the periodontal pathogens, P. gingivalis and B. forsythus, were detected even in the youngest subjects. Species associated with caries included S. mutans (children ages 18-36 mos) and A. israelii (children ages < 18 mos), the latter species possibly reflecting increased plaque in children with caries. Species detection from tooth and tongue samples was highly associated, with most species detected more frequently from tongue than from tooth samples in children under 18 mos, suggesting that the tongue was a potential microbial reservoir.

An economic evaluation of a chlorhexidine chip for treating chronic periodontitis: the CHIP (chlorhexidine in periodontitis) study

BACKGROUND

The authors previously suggested that an adjunctive, controlled-release chlorhexidine, or CHX, chip may reduce periodontal surgical needs at little additional cost. This article presents an economic analysis of the CHX chip in general dental practice.

METHODS

In a one-year prospective clinical trial, 484 chronic periodontitis patients in 52 general practices across the United States were treated with either scaling and root planing, or SRP, plus any therapy prescribed by treating, unblinded dentists; or SRP plus other therapy as above but including the CHX chip. Economic data were collected from bills, case report forms and 12-month treatment recommendations from blinded periodontist evaluators.

RESULTS

Total dental charges were higher for SRP + CHX chip patients vs. SRP patients when CHX chip costs were included (P = .027) but lower when CHX chip costs were excluded (P = .012). About one-half of the CHX chip acquisition cost was offset by savings in other charges. SRP + CHX chip patients were about 50 percent less likely to undergo surgical procedures than were SRP patients (P = .021). At the end of the trial, periodontist evaluators recommended similar additional procedures for both groups: SRP, about 46 percent; maintenance, about 37 percent; surgery, 56 percent for SRP alone and 63 percent for SRP + CHX chip.

CONCLUSIONS

Adjunctive CHX chip use for general-practice patients with periodontitis increased costs but reduced surgeries over one year. At study's end, periodontists recommended similar additional surgical treatment for both groups.

CLINICAL IMPLICATIONS

In general practice, routine use of the CHX chip suggests that costs will be partially offset by reduced surgery over at least one year.

Fimbriae of Porphyromonas gingivalis induce opsonic antibodies that significantly enhance phagocytosis and killing by human polymorphonuclear leukocytes

Porphyromonas gingivalis has been strongly implicated in the pathogenesis of human periodontitis. Fimbriae mediate adherence and colonization of the oral cavity by this organism and may, therefore, have potential for use as antigen in an anti-P. gingivalis vaccine. The purpose of our study was to determine whether P. gingivalis fimbriae have opsonic target sites and whether they are accessible on the cell surfaces and cross-reactive among P. gingivalis fimbrial types and serotypes. Rabbits were immunized with a vaccine. The antiserum reacted with a 43-kDa fimbrillin monomer and a 43-kDa component in whole-cell sonicates of P. gingivalis 33277, but it showed only very weak reactivity in the 43-kDa region of Western blots of a whole-cell sonicate of strain DPG3, a mutant that does not express functional fimbriae. The antibody enhanced chemiluminescence approximately six-fold relative to preimmune serum values and significantly enhanced phagocytosis and killing of P. gingivalis 33277 by human polymorphonuclear leukocytes. Peak opsonic activity was observed at week 6 followed by a plateau that remained until week 16. The fimbria-deficient mutant DPG3 did not bind antifimbrial antibody and was not opsonized, whereas strain 381, the parent of the mutant, was opsonized. The specific antibody bound to and opsonized P. gingivalis strains 33277 and 381 (fimbria type I) but not W50, A7A-1-28, 9-14K-1 or FAY-19M-1 (fimbrial types II-V). Specific antibody bound to strain 2561 (fimbrial type I) but, as assessed by chemiluminescence, did not opsonize it. While fimbriae have opsonic target sites that are accessible on P. gingivalis cell surfaces, the relevant opsonic target sites do not appear to be shared across serotypes or fimbrial types. Thus, a vaccine containing, as antigen, fimbrial protein from a single P. gingivalis strain would likely be ineffective against infections by P. gingivalis strains expressing other fimbrial types.

Functional characteristics of antibodies induced by Arg-gingipain (HRgpA) and Lys-gingipain (Kgp) from Porphyromonas gingivalis

Arginine-specific gingipain (HRgpA) and lysine-specific gingipain (Kgp), enzymes produced by Porphyromonas gingivalis, may be candidates for an anti-P. gingivalis vaccine. The purpose of our study was to determine whether HRgpA and Kgp have opsonic target sites and whether these sites are available and accessible on intact P. gingivalis cells. Rabbits were used to generate polyclonal antibodies to both proteins. Animals were immunized and immunoglobulin G (IgG) fractions were isolated from preimmune and immune sera. Functional characteristics of the antibodies were assessed by determining antibody titers by enzyme-linked immunosorbent assay (ELISA), generating Western immunoblots, and measuring antibody enhancement of P. gingivalis opsonization, phagocytosis and killing by polymorphonuclear leukocytes (PMN) of intact cells of strains of P. gingivalis representative of the four serotypes. Strains studied included 33277 (serotype A), A7A1-28 (serotype B), W50 (serotype C) and 381 (serotype D). Both HRgpA and Kgp induced high titers of IgG antibody. Anti-HRgpA and anti-Kgp bound to both HRgpA and Kgp demonstrating a large proportion of shared antigenic epitopes. The two antibodies bound equally well to all four P. gingivalis serotypes with titers ranging from 77 to 205 ELISA units when compared to preimmune IgG set at 1 ELISA unit. The immunoblot patterns of binding of the two antibodies to HRgpA and Kgp and to sonicates of the four P. gingivalis serotypes were virtually identical. Both antibodies detected components in HRgpA at 27, 35 and 45 kDa and in Kgp at 27, 32, 35, 40 and 55 kDa. The antibodies also detected components at or near these same positions in addition to multiple high molecular mass components in the cell sonicates of P. gingivalis. Both proteins induced antibodies that significantly enhanced opsonization as assessed by chemiluminescence, with values ranging from 130 mV to 375 mV for anti-HRgpA IgG and from 240 mV to 475 mV for anti-Kgp IgG. Both antibodies significantly enhanced PMN-mediated bacterial killing of the four P. gingivalis serotypes, although the percentage of killing varied among the serotypes (24-81% for anti-HRgpA and 37-89% for anti-Kgp). Thus, both HRgpA and Kgp express opsonic target sites and induce high titers of antibodies that opsonize and enhance killing of all four serotypes of P. gingivalis. These two proteins appear to be potential candidate antigens for an anti-P. gingivalis vaccine.

Immunoglobulin G response of periodontitis patients to Porphyromonas gingivalis capsular carbohydrate and lipopolysaccharide antigens

Porphyromonas gingivalis clonal types that participate in periodontal infections express serologically distinct surface antigens. This investigation sought to determine whether serum antibodies titers against the serotype-specific capsular carbohydrate K antigen and lipopolysaccharide antigens of P. gingivalis might reveal which serotypes are most likely to be responsible for subgingival infections in subjects with adult periodontitis. Immunoglobulin G (IgG) titers to purified K antigen and lipopolysaccharide from different P. gingivalis strains were measured by ELISA for 28 healthy controls and 51 patients with periodontal pockets known to be infected with genetically and serologically distinct P. gingivalis clonal types. Titers to purified K antigen from strains W50, HG184, A7A1-28, 49417, HG1690 and HG1691, representing serotypes K1-K6, respectively, and lipopolysaccharide from strains 381, HG1691 and W50, representing serotypes O1-O3, respectively, were measured for all subjects. Chi-square likelihood ratios, Mann-Whitney tests and receiver-operating characteristic sensitivity-specificity plots were used to compare the accuracy with which titer results for different target antigens classified subjects with or without disease. Results from assays targeting K2, K3, K4, K5, O1 and O2 generally gave poor diagnostic accuracy, whether evaluated separately or as summed titer pairs corresponding to the K/O combinations actually expressed by the target antigen parent strains. Exceptions were O3 (from W50) and K5+O2 (both from HG1690), which gave moderate accuracy in classifying subjects. In contrast, highly significant diagnostic accuracy was achieved using individual K1 (W50) and K6 (HG1691) titer data and K1+O3 (W50) and K6+O2 (HG1691) titer sum values. These observations suggest that P. gingivalis clonal types expressing K/O serotypes matching those of W50 (K1/O3) and HG1691 (K6/O2) are more likely than others to participate in periodontal infections in adult periodontitis patients and thus are more likely than others to express relevant virulence factors.

The effect of the menopause on prolactin levels in patients with hyperprolactinaemia

OBJECTIVE

Microprolactinomas have been reported to resolve spontaneously after pregnancy and there have been suggestions that oestrogen therapy increases the size of microprolactinomas. Little is known, however, about the effect of the menopause in patients previously known to be hyperprolactinaemic. The aim of this study was to find out if pregnancy or the menopause leads to an alteration in prolactin levels.

DESIGN

We conducted a retrospective study of 148 case notes of patients with hyperprolactinaemia and microprolactinomas treated at the Radcliffe Infirmary during the period 1976-96. Sixty-nine female patients who had not had pituitary surgery as treatment for microprolactinoma were used as a control group. None of this group became pregnant or reached the menopause. They were compared with 25 female patients who became pregnant, 11 who became menopausal and 11 who were male. Subjects were excluded from the analysis if there were no follow-up data off dopamine agonist treatment or if they were surgically cured. Data were gathered on demographic parameters, treatment given, scan abnormalities, prolactin levels at diagnosis and last follow up, prolactin levels pre- and postpregnancy as well as pre- and postmenopause. The pregnancy, postmenopausal and male patient groups were compared with the control group and each other to see if they had a higher frequency of normalization of their prolactin levels during follow up. Various factors were examined as possible variables for the normalization of prolactin, including the detection of scan abnormalities at diagnosis, prolactin levels at diagnosis as well as treatment with dopamine agonists and duration of follow up.

RESULTS

Forty-five percent of the menopausal group, 24% of the pregnancy group and 18% of the male group subsequently normalized their prolactin levels during the period of the study in comparison with 7% of the control group. The menopausal groups had a significantly higher chance of normalizing their prolactin compared to the control group (P < 0.005), whilst the pregnancy group showed a non-significant trend towards normalizing their prolactin (P = 0.06). The detection of scan abnormalities, treatment with dopamine agonist therapy and duration of follow up were not associated with normalization of prolactin levels.

CONCLUSION

Female patients with hyperprolactinaemia who pass through the menopause have a significant chance of normalizing their prolactin levels. Females who pass through pregnancy may have a higher chance of normalizing their prolactin levels. The menopause is an indication for reassessment of the need to continue to treat hyperprolactinaemia and microprolactinoma.

Antigenic cross-reactivity among Porphyromonas gingivalis serotypes

The goal of our research program is to develop a Porphyromonas gingivalis vaccine. Vaccine development requires identification of antigenic components shared by the many clonal types of P. gingivalis. The purpose of the present study was to evaluate the extent and nature of antigenic cross-reactivity among serotypes of P. gingivalis and to identify shared antigenic components. Strains selected to represent serotypes A-D were 33277, A7A1-28 W50 and 381, respectively. Using intact cells, antibodies were raised in rabbits. Titers were assessed by enzyme-linked immunosorbent assay (ELISA) using intact cells as antigen, Western blots were prepared and biologic activity was measured as opsonization (chemiluminescence expressed as mV) and enhancement of phagocytosis and killing by polymorphonuclear leukocytes. Extensive cross-reactivity that varied greatly among serotypes was observed by ELISA. The Western blots showed an even greater extent of cross-reactivity, with shared protein components at approximately 140, 130, 37, 32 and 28 kDa and a shared variable molecular mass smear considered to be lipopolysaccharide and other carbohydrate. Additional protein components at 110, 85, 35 and 20 kDa appeared to be shared by some but not all serotypes. In the functional assays, strains 33277 and 381 were equally well opsonized by anti-33277 and anti-381 (500-650 mV) but opsonized to a much lesser extent by anti-A7A1-28 and anti-W50 (roughly 125 mV and 350 mV respectively). A7A1-28 and W50 were opsonized by all four immune sera almost equally but to a much lower extent (roughly 400 mV and 250 mV respectively). Enhancement of phagocytosis and killing in the presence of active complement mirrored opsonization with the exception that 381 was reasonably well opsonized by anti-A7A1-28 (400 mV) and anti-W50 (350 mV), but poorly killed. The protein components at 140, 130, 37 and 28 kDa shared by all of the four serotypes appear to have potential as vaccine candidate antigens.

Bioequivalence study of stressed and nonstressed hard gelatin capsules using amoxicillin as a drug marker and gamma scintigraphy to confirm time and GI location of in vivo capsule rupture

PURPOSE

Evaluate if crosslinked hard gelatin capsules (HGCs) having different in vitro dissolution profiles changed in vivo release times or altered bioavailability of a drug marker; assess if a two-tier dissolution test (with and without enzyme) predicted in vivo performance.

METHODS

Two classifications of stressed HGCs were artificially produced by exposure to formaldehyde (HCHO). HGCs were categorized as, a) pass/pass (p/p) which met in vitro dissolution criterion (75% drug dissolution at 45 min), b) moderately crosslinked fail/pass (f/p) which failed dissolution criterion in the absence of enzymes and passed in the presence of enzymes, and c) severely crosslinked fail/fail (f/f) which failed in vitro standards with or without enzymes. A six-way, single dose bioequivalence study (n = 10) administered the three HGCs under the fasted and fed condition. In vivo capsule rupture and GI transit were monitored via gamma scintigraphy, and blood samples were collected through six hours.

RESULTS

Each crosslinked HGC was bioequivalent to the control p/p capsule when using AUC(0-infinity) and Cmax for comparison. Mean in vivo disintegration of the p/p capsule was 7 +/- 5 min for the fasted condition and 11 +/- 7 min for the fed condition. In vivo rupture for the f/p capsule was 22 +/- 12 min and 23 +/- 11 min for the fasted and fed studies, respectively, while the f/f HGC ruptured at 31 +/- 15 min and 71 +/- 19 min under the fasted and fed condition, respectively. Onset of amoxicillin absorption was dependent on in vivo HGC rupture and subsequent entry of the released radioactive marker into the small intestine. Consequently, fasted Tmax values were significantly later for the f/p HGC (1.62 +/- 0.53 hr) and f/f HGC (1.85 +/- 0.58 hr) as compared to the p/p HGC (1.17 +/- 0.30 hr). Fed Tmax values were statistically different only for the f/f capsule (2.55 +/- 0.44 hr) where Tmax values for the p/p and f/p HGCs under the fed condition were 1.50 +/- 0.47 hr and 1.60 +/- 0.46 hr, respectively.

CONCLUSIONS

A two-tier dissolution procedure that retested a crosslinked hard gelatin capsule with addition of gastric or intestinal enzymes provided an adequate in vitro indicator of the formulation's in vivo performance. The observed delays in the onset of amoxicillin absorption and Tmax for the severely crosslinked f/f HGC was attributed to delayed in vivo capsule rupture, however, this delay did not adversely change AUC(0-infinity) nor Cmax.

Vaccination and periodontitis: myth or reality

In most industrialised countries approximately 15% of the population has enhanced risk for moderate to severe periodontitis. The disease is caused by infection by gram-negative, anaerobic bacteria including Porphyromonas gingivalis and Bacteroides forsythus. There is evidence that P. gingivalis is a key pathogen. Using ligature-induced periodontitis in the non-human primate Macaca fascicularis as a model, we immunised 10 animals using intact killed P. gingivalis and SAF-M adjuvant and 10 controls using adjuvant only. The vaccine, containing 250 microg protein/ml, was injected subcutaneously in the neck and into the deltoid muscle (0.5 ml each site) at baseline and weeks 3, 6, and 16, and the mandibular posterior teeth ligated at week 16. At weeks 30 and 36 changes in alveolar bone, measured using digital subtraction radiography, were used as the outcome measure. Even though periodontitis in humans and in this animal model is a polymicrobial disease, immunisation with a vaccine containing a single bacterial species, P. gingivalis, induced protection. Of all the P. gingivalis components that have been studied, the cysteine proteases have the greatest potential as vaccine antigens. In a pilot study using the same protocol, we have shown that porphypain-2 purified from P. gingivalis is effective in inducing protection. Although opsonisation and bacterial cell killing may be involved in protection, other mechanisms such as antibody mediated reduction of levels of inflammatory mediators such as PGE2 and neutralisation of virulence factors may be important. In neither the whole cell vaccine nor the purified cysteine protease vaccine studies were signs of toxicity observed. In light of the increasing evidence that periodontitis significantly increases risk for potentially fatal diseases such as coronary heart disease, stroke and complications from diabetes mellitus a successful vaccine for periodontitis could have health benefits far exceeding the prevention of periodontitis.

Milestones in periodontal research and the remaining critical issues

A significant recent development in periodontal research has been the convergence of basic and clinical research resulting in a logarithmic increase in the rate of progress. Scientific consensus has been reached in many areas. In most populations, moderate to severe periodontitis affects a relatively small segment of adults who are at high risk. The microbial etiology is accepted and the identity of the major pathogenic bacterial species is known. The mechanisms through which resistant individuals successfully fend off the microbial challenge are known, and the immuno-inflammatory pathways activated by bacteria that underlie destruction of the alveolar bone and the connective tissues of the periodontium are reasonably well understood. The evidence shows that these pathways are held in common by all forms of periodontitis. Therapeutic modulation of these pathways is now possible, and new treatments based on such modulation are now becoming available. Although bacteria are essential for disease to occur, they are insufficient; a susceptible host is also necessary. Host susceptibility, disease progression and response to treatment are determined predominantly by heredity and environmental and acquired risk factors. Some of these can be changed while others are immutable. Concepts and procedures for treatment are generally scientifically based and appropriately applied. Preventive measures are largely successful and widely practiced in industrialized countries. Clearly, control of these ancient chronic diseases is now within our reach. In spite of the tremendous progress, many unresolved issues remain. The purpose of this paper is to summarize some of the major accomplishments of periodontal research, and identify and discuss some of the more important critical issues that still need to be addressed.

Outcome of transphenoidal surgery for acromegaly and its relationship to surgical experience

BACKGROUND

A number of surgical series have been reported on the treatment of acromegaly and their results vary widely. The acceptable definition of remission has changed in recent years and it is known, though in a small series, that growth hormone levels of > 5 mU/l are still associated with an increased mortality from the condition. We have analysed data at this centre and examined the outcome of transphenoidal surgery for acromegaly, compared our results with recently published series from other centres and also assessed factors which might effect outcome including whether there is any demonstrable effect of the experience of the surgeon on outcome.

PATIENTS AND METHODS

We have analysed data from all of our 139 patients in whom follow up data are available who have undergone initial transphenoidal surgery for acromegaly by one surgeon at this centre, between 1974 and 1995. Follow up was for a median of 5 years (range 1 month to 17 years).

RESULTS

67% of patients achieved the criterion for remission (mean GH < 5 mU/l). Success was related to tumour size and preoperative growth hormone values. Thus 91% of patients with microadenomas were in remission postoperatively compared to 46% of patients with macroadenomas. Analysis of the results according to the year of operation showed an improvement in success rates with time. More than 15 years ago, the success rate according to the growth hormone criteria set was 48% and the failure rate 52%. In contrast in the last 5 years analysed, the overall success rate was 74% with a failure rate of 26% (P < 0.04). The success rate for microadenomas was 50% initially, then remained 100%. The case mix was analysed and no change was found. We have also demonstrated an improvement in pituitary function (including normalization of preoperative elevated prolactin) with time so that pre 1981 16% of patients' pituitary function improved perioperatively but 10 years later this figure had risen to 34% (P < 0.03). There was no change over time in the development of pituitary hypofunction, complication rate or recurrence rate.

CONCLUSION

Surgical treatment is a safe and effective treatment for acromegaly and remains the first choice of treatment for most acromegalic patients. The results of this centre compare favourably with series from other centres. We have demonstrated improved results, both in terms of post operative growth hormone values and pituitary function tests with time and increasing neurosurgical experience. We conclude that outcome for the surgical treatment for acromegaly is best achieved with one surgeon specialising in pituitary surgery. Improved operative outcome thus achieved has major cost implications and avoids the necessity for consideration of postoperative radiotherapy and the use of expensive growth hormone suppressing drugs in the postoperative period.

Function of anti-Porphyromonas gingivalis immunoglobulin classes in immunized Macaca fascicularis

We previously reported that Macaca fascicularis immunized with formalin-killed Porphyromonas gingivalis were protected against the bone loss of periodontitis. To examine mechanisms of protection, we determined specific immunoglobulin G (IgG), IgM and IgA titers and opsonic capacities of sera from immunized and control animals. Serum IgG and IgA titers to P. gingivalis appeared early and persisted throughout the 36-week observation period. IgM titers were elevated until 6 to 12 weeks and then decreased through week 36. A significant association was observed between peak IgM titers prior to ligature placement and protection against bone loss (measured at week 30). In control monkeys, no significant IgG, IgA or IgM titers were seen. In sera from immunized animals, significant opsonic capacity was seen by 6-12 weeks and persisted throughout the study. In contrast, control sera showed only low opsonization capacity. Anti P. gingivalis antibody titers in purified IgG, IgA and IgM fractions were determined by enzyme-linked immunosorbent assay, and opsonic activity was demonstrated only in the IgG fraction.

Antigenic variation in Porphyromonas gingivalis ribotypes recognized by serum immunoglobulin G of adult periodontitis patients

We obtained clinical isolates of Porphyromonas gingivalis of known ribotype from patients diagnosed with adult periodontitis and used Western blot methodology to evaluate profiles of antigens recognized by IgG in heterologous and homologous patient sera. Our aims were to identify isolates belonging to different serogroups, to learn if serogroup membership is related to ribotype to assess variation in IgG responses of patients to antigens is homologous and heterologous ribotypes, and to determine the frequency of shared and variable antigens in different biochemical classes recognized across different serogroups and ribotypes. Blots of separation patterns of 28 isolates were developed in sera from patients and bound IgG was quantified by digital image densitometry. The membership of isolates in different serogroups was determined by correlation and hierarchical cluster analysis of isolate whole-cell IgG binding profiles. Two major isolate clusters, each with two subclusters, were found. Isolates within the same ribotype clustered together in some cases but not others. Homologous isolates ranked high in IgG binding levels relative to those from different patients irrespective of ribotype. Patient subgroups with IgG responses dominant for different ribotypes and serogroups were revealed by correlation analysis. The IgG binding profiles observed for individual protein and proteinase-resistant antigens across both homologous and heterologous isolates were very dissimilar. Furthermore, the frequency of antigens both shared across all ribotypes and recognized by IgG in patient sera was unexpectedly low. Only two protein antigens (Mr 44 kDa and 27 kDa) were strongly recognized across all ribotypes by different sera. We conclude that the IgG response of patients infected with a particular P. gingivalis serotype or ribotype is directed mainly against antigens that are not shared by other potentially infective clonal types.

Differential proliferation of fibroblasts cultured from hereditary gingival fibromatosis and normal gingiva

Hereditary gingival fibromatosis (HGF) is an oral condition characterized by the enlargement of the gingiva of both the maxilla and mandible. To study the cell proliferation index of fibroblasts from HGF and normal gingiva (NG), cell cultures from 4 members of the same family with HGF and from 4 healthy patients were established. Our results obtained from 6 different cell proliferation assays clearly showed that the cell proliferation rate was significantly higher in fibroblasts from HGF than from normal gingiva. HGF and control fibroblasts in subconfluent culture densities were typically spindle, but in saturation density HGF cells were shorter than control cells. These data suggest that the higher proliferative index of HGF fibroblasts possibly has a role in the pathogenesis of gingival outgrowth in HGF patients.