Factors influencing outcomes of surgical therapy of peri-implantitis: A secondary analysis of 1-year results from a randomized clinical study

AIM

To identify predictors of treatment outcomes following surgical therapy of peri-implantitis.

MATERIALS AND METHODS

We performed a secondary analysis of data from a randomized controlled trial (RCT) comparing access flap with or without bone replacement graft. Outcomes at 12 months were probing pocket depth (PPD), bleeding on probing (BOP), soft-tissue recession (REC) and marginal bone level (MBL) change. Multilevel regression analyses were used to identify predictors. We also built an explanatory model for residual signs of inflammation.

RESULTS

Baseline PPD was the most relevant predictor, showing positive associations with final PPD, REC and MBL gain, and negative association with probability of pocket closure. Smokers presented higher residual PPD. Absence of keratinized mucosa at baseline increased the probability of BOP but was otherwise not indicative of outcomes. Plaque at 6 weeks was detrimental in terms of residual PPD and BOP. Treatment allocation had an effect on REC. Final BOP was explained by residual PPD ≥6 mm and plaque at more than two sites.

CONCLUSIONS

Baseline PPD was the most relevant predictor of the outcomes of surgical therapy of peri-implantitis. Pocket closure should be a primary goal of treatment. Bone replacement grafts may be indicated in aesthetically demanding cases to reduce soft-tissue recession. The importance of smoking cessation and patient-performed plaque control is also underlined.

Efficacy of access flap and pocket elimination procedures in the management of peri-implantitis: A systematic review and meta-analysis

AIM

To evaluate the efficacy of access flap and pocket elimination procedures in the surgical treatment of peri-implantitis.

MATERIALS AND METHODS

Systematic electronic searches (Central/MEDLINE/EMBASE) up to March 2022 were conducted to identify prospective clinical studies evaluating surgical therapy (access flap or pocket elimination procedures) of peri-implantitis. Primary outcome measures were reduction of probing depth (PD) and bleeding on probing (BOP). Risk of bias was evaluated according to study design. Meta-analysis and meta-regression were performed. Results were expressed as standardized mean effect with 95% confidence interval (CI).

RESULTS

Evidence from studies directly comparing surgical with non-surgical therapy is lacking. Based on pre-post data originating from 13 prospective patient cohorts, pronounced reductions of PD (standardized mean effect: 2.2 mm; 95% CI 1.8-2.7) and BOP% (27.0; 95% CI 19.8-34.2) as well as marginal bone level gain (0.2 mm; 95% CI -0.0 to 0.5) were observed at evaluation time points ranging from 1 to 5 years. Wide prediction intervals suggested a high degree of heterogeneity. Reduction of mean PD increased by 0.7 mm (95% CI 0.5-0.9) for every millimetre in increase of mean PD at baseline. During the follow-up period ranging from 1 to 5 years, disease recurrence occurred frequently and implant loss was not uncommon.

CONCLUSIONS

Access flap and pocket elimination surgery are effective procedures in the management of peri-implantitis, although rates of disease recurrence during 5 years were high. Treatment outcomes were affected by baseline conditions.

Reconstructive surgical therapy of peri-implantitis: A multicenter randomized controlled clinical trial

OBJECTIVE

To evaluate the potential benefit of the use of a bone substitute material in the reconstructive surgical therapy of peri-implantitis.

METHODS

In this multicenter randomized clinical trial, 138 patients (147 implants) with peri-implantitis were treated surgically, randomized by coin toss to either a control (access flap surgery) or a test group (reconstructive surgery using bone substitute material). Clinical assessments, including probing pocket depth (PPD), bleeding and suppuration on probing (BOP & SOP) as well as soft tissue recession (REC), were recorded at baseline, 6 and 12 months. Marginal bone levels (MBL), measured on intra-oral radiographs, and patient-reported outcomes (PROs) were recorded at baseline and 12 months. No blinding to group allocation was performed. The primary outcome at 12 months was a composite measure including (i) implant not lost, (ii) absence of BOP/SOP at all aspects, (iii) PPD ≤5 mm at all aspects and (iv) ≤1 mm recession of mucosal margin on the buccal aspect of the implant. Secondary outcomes included (i) changes of MBL, (ii) changes of PPD, BOP%, and buccal KM, (iii) buccal REC and (iv) patient-reported outcomes.

RESULTS

During follow-up, four implants (one in the test group, three in the control group) in four patients were removed due to disease progression. At 12 months, a total of 69 implants in the test and 68 implants in the control group were examined. Thus, 16.4% and 13.5% of implants in the test and control group, respectively, met all predefined criteria of the composite outcome. PPD reduction and MBL gain were 3.7 mm and about 1.0 mm in both groups. Reduction in mean BOP% varied between 45% (test) and 50% (control), without significant differences between groups. Buccal REC was less pronounced in the test group (M = 0.7, SD = 0.9 mm) when compared to controls (M = 1.1, SD = 1.5 mm). PROs were favorable in both groups without significant differences. One case of allergic reaction to the antibiotic therapy was recorded. No other adverse events were noted.

CONCLUSIONS

Surgical therapy of peri-implantitis effectively improved the clinical and radiographic status at 12 months. While the use of a bone substitute material did not improve reductions of PPD and BOP, buccal REC was less pronounced in the test group. Patient satisfaction was high in both groups.

Health economic aspects of implant-supported restorative therapy

BACKGROUND

It is poorly understood how much additional dental care patients consume subsequent to implant therapy. The aim of the present study is to evaluate costs associated with implant-supported restorative therapy during the long-term follow-up.

MATERIAL AND METHODS

Costs associated with preventive measures and complication-related procedures over a mean follow-up period of 8.2 years were assessed in patient files of 514 Swedish subjects provided with implant-supported restorative therapy. The restorative therapy and each of the subsequent interventions were assigned a specific cost. Accumulated costs were calculated in three categories: (i) total cost including initial restorative therapy and complication-related interventions, (ii) cost of preventive measures alone, and (iii) cost of complication-related procedures alone. Potential differences by background variables were analyzed using growth curve models.

RESULTS

In the whole sample, costs during follow-up ranged from 878 € (95% CI 743; 1,014) for patients with single-tooth restoration(s) to 1,210 € (95% CI 1,091; 1,329) for subjects with full-jaw restoration(s). The majority of costs during follow-up originated from preventive measures (741 € 95% CI 716; 766). Among individuals receiving ≥1 intervention dealing with a complication (n = 253), complication-related costs amounted to 557 € (95% CI 480; 634). For patients with full-jaw restorations, the corresponding amount was 769 € (95% CI 622; 916). Procedures related to peri-implantitis and technical complications resulted in costs similar to each other. Implant loss generated greater costs than any other type of complication.

CONCLUSIONS

Costs related to implant-supported restorative therapy during follow-up were associated with the extent of initial therapy. The higher costs during follow-up noted in patients provided with full-jaw restorations were explained by complication-associated procedures. Implant loss was the most costly type of complication.

Performance evaluation of survival regression models in analysing Swedish dental implant complication data with frailty

The use of inappropriate methods for estimating the effects of covariates in survival data with frailty leads to erroneous conclusions in medical research. This study evaluated the performance of 13 survival regression models in assessing the factors associated with the timing of complications in implant-supported dental restorations in a Swedish cohort. Data were obtained from randomly selected cohort (n = 596) of Swedish patients provided with dental restorations supported in 2003. Patients were evaluated over 9 years of implant loss, peri-implantitis or technical complications. Best Model was identified using goodness, AIC and BIC. The loglikelihood, the AIC and BIC were consistently lower in flexible parametric model with frailty (df = 2) than other models. Adjusted hazard of implant complications was 45% (adjusted Hazard Ratio (aHR) = 1.449; 95% Confidence Interval (CI): 1.153-1.821, p = 0.001) higher among patients with periodontitis. While controlling for other variables, the hazard of implant complications was about 5 times (aHR = 4.641; 95% CI: 2.911-7.401, p<0.001) and 2 times (aHR = 2.338; 95% CI: 1.553-3.519, p<0.001) higher among patients with full- and partial-jaw restorations than those with single crowns. Flexible parametric survival model with frailty are the most suitable for modelling implant complications among the studied patients.

Occurrence and clustering of complications in implant dentistry

OBJECTIVES

The aim was to evaluate the overall occurrence and potential clustering of biological and technical complications in implant dentistry.

MATERIAL AND METHODS

596 patients provided with implant-supported reconstructions were evaluated for the occurrence of (a) technical complications, (b) peri-implantitis and (c) implant loss during a period of 9 years. Time and type of event were scored, and potential risk factors were explored through parametric modelling of survival and hazards. Clustering of complications was assessed at the patient level, and patient satisfaction was evaluated by questionnaire completed at the 9-year examination.

RESULTS

42% of patients were affected by technical and/or biological complications during the 9-year observation period. Extent of therapy (Hazard Ratio 2.5: patients with partial jaw restorations; HR 3.9: patients with full jaw restorations) and a history of periodontitis (HR 1.6) were identified as risk factors. While technical complications occurred mostly as isolated events, 41% of subjects identified with peri-implantitis and 52% of subjects with implant loss also presented with other complications. The hazard for technical complications and implant loss peaked at 0.7 years and 0.2 years, respectively, while the hazard for peri-implantitis was consistent throughout the observation period. The overall proportion of satisfied patients at 9 years was high (95%), and only minor differences between individuals with and without complications were noted.

CONCLUSIONS

Complications following implant-supported restorative therapy were common findings. Extent of therapy and periodontitis were identified as risk factors. While technical complications occurred in an isolated pattern, peri-implantitis and implant loss demonstrated clustering with other types of complications.

Advanced Methods for Dose and Regimen Finding During Drug Development: Summary of the EMA/EFPIA Workshop on Dose Finding (London 4-5 December 2014)

Inadequate dose selection for confirmatory trials is currently still one of the most challenging issues in drug development, as illustrated by high rates of late‐stage attritions in clinical development and postmarketing commitments required by regulatory institutions. In an effort to shift the current paradigm in dose and regimen selection and highlight the availability and usefulness of well‐established and regulatory‐acceptable methods, the European Medicines Agency (EMA) in collaboration with the European Federation of Pharmaceutical Industries Association (EFPIA) hosted a multistakeholder workshop on dose finding (London 4–5 December 2014). Some methodologies that could constitute a toolkit for drug developers and regulators were presented. These methods are described in the present report: they include five advanced methods for data analysis (empirical regression models, pharmacometrics models, quantitative systems pharmacology models, MCP‐Mod, and model averaging) and three methods for study design optimization (Fisher information matrix (FIM)‐based methods, clinical trial simulations, and adaptive studies). Pairwise comparisons were also discussed during the workshop; however, mostly for historical reasons. This paper discusses the added value and limitations of these methods as well as challenges for their implementation. Some applications in different therapeutic areas are also summarized, in line with the discussions at the workshop. There was agreement at the workshop on the fact that selection of dose for phase III is an estimation problem and should not be addressed via hypothesis testing. Dose selection for phase III trials should be informed by well‐designed dose‐finding studies; however, the specific choice of method(s) will depend on several aspects and it is not possible to recommend a generalized decision tree. There are many valuable methods available, the methods are not mutually exclusive, and they should be used in conjunction to ensure a scientifically rigorous understanding of the dosing rationale.

Evidence-based or traditional treatment of cancer-related lymphedema

The incidence of lymphedema (LE) related to treatment of women's cancer (breast and gynecologic) is as high as 40%. Treatment of LE varies around the world but was decades ago initially based on programs including manual lymph drainage (MLD), compression, skin care and easy exercise. With accumulating evidence and experience, it is time to consider if altering these treatment principles is needed. Based on accumulating evidence, we suggest less emphasis on manual lymph drainage and more on early diagnosis, compression, weight control and exercise for improvement of strength and circulation.

Long-term efficacy of Internet-based cognitive behavior therapy for obsessive-compulsive disorder with or without booster: a randomized controlled trial

BACKGROUND

As relapse after completed cognitive behavior therapy (CBT) for obsessive-compulsive disorder (OCD) is common, many treatment protocols include booster programs to improve the long-term effects. However, the effects of booster programs are not well studied. In this study, we investigated the long-term efficacy of Internet-based CBT (ICBT) with therapist support for OCD with or without an Internet-based booster program.

METHOD

A total of 101 participants were included in the long-term follow-up analysis of ICBT. Of these, 93 were randomized to a booster program or no booster program. Outcome assessments were collected at 4, 7, 12 and 24 months after receiving ICBT.

RESULTS

The entire sample had sustained long-term effects from pre-treatment to all follow-up assessments, with large within-group effect sizes (Cohen's d = 1.58-2.09). The booster group had a significant mean reduction in OCD symptoms compared to the control condition from booster baseline (4 months) to 7 months, but not at 12 or 24 months. Participants in the booster group improved significantly in terms of general functioning at 7, 12 and 24 months, and had fewer relapses. Kaplan-Meier analysis also indicated a significantly slower relapse rate in the booster group.

CONCLUSIONS

The results suggest that ICBT has sustained long-term effects and that adding an Internet-based booster program can further improve long-term outcome and prevent relapse for some OCD patients.

Mn-induced modifications of Ga 3d photoemission from (Ga, Mn)As: evidence for long range effects

Using synchrotron based photoemission, we have investigated the Mn-induced changes in Ga 3d core level spectra from as-grown Ga(1-x)Mn(x)As. Although Mn is located in Ga substitutional sites, and therefore does not have any Ga nearest neighbors, the impact of Mn on the Ga core level spectra is pronounced even at Mn concentrations in the region of 0.5%. The analysis shows that each Mn atom affects a volume corresponding to a sphere with around 1.4 nm diameter.

Thermal diffusion of Mn through GaAs overlayers on (Ga, Mn)As

Thermally stimulated diffusion of Mn through thin layers of GaAs has been studied by x-ray photoemission. (Ga, Mn)As samples with 5 at% Mn were capped with 4, 6 and 8 monolayer (ML) GaAs, and Mn diffusing through the GaAs was trapped on the surface by means of amorphous As. It was found that the out-diffusion is completely suppressed for an 8 ML thick GaAs film. The short diffusion length is attributed to an electrostatic barrier formed at the (Ga, Mn)As/GaAs interface.

Fluctuation-induced drift in a gravitationally tilted optical lattice

Experimental and theoretical studies are made of Brownian particles trapped in a periodic potential, which is very slightly tilted due to gravity. In the presence of fluctuations, these will trigger a measurable average drift along the direction of the tilt. The magnitude of the drift varies with the ratio between the bias force and the trapping potential. This can be closely compared to a theoretical model system, based on a Fokker-Planck-equation formalism. We show that the level of control and measurement precision we have in our system, which is based on cold atoms trapped in a three-dimensional dissipative optical lattice, makes the experimental setup suitable as a testbed for fundamental statistical physics. We simulate the system with a very simplified and general classical model, as well as with an elaborate semiclassical Monte Carlo simulation. In both cases, we achieve good qualitative agreement with experimental data.

Early insulin response in latent gestational diabetes

The intravenous glucose tolerance and glucose-stimulated early insulin response (EIR) were studied in late pregnancy and post partum in a reference (R) group of 9 women and in 18 women with latent gestational diabetes (LD), defined as a k-value of < 0.66/h and a normal fasting blood glucose concentration. During pregnancy, the LD group showed a lower EIR than the R group. However, the response ranged between normal and non-detectable. In the non-pregnant state, the EIR was the same in the two groups. The inability to increase the EIR during pregnancy wss most evident in women who even post partum had an abnormal glucose tolerance. In some women in the LD group, the EIR during pregnancy was even lower than in the non-pregnant state. The magnitude of the response in the non-pregnant state was not decisive of the capacity to increase the secretion during pregnancy. None of the women in the LD group developed manifest diabetes during pregnancy. They gave birth to children with normal birth weight, and no neonatal problems were registered except for one child with congenital heart malformation.

The BCL-2 promoter (-938C>A) polymorphism does not predict clinical outcome in chronic lymphocytic leukemia

The (-938C>A) polymorphism in the promoter region of the BCL-2 gene was recently associated with inferior time to treatment and overall survival in B-cell chronic lymphocytic leukemia (CLL) patients displaying the -938A/A genotype and may thus serve as an unfavorable genetic marker in CLL. Furthermore, the -938A/A genotype was associated with increased expression of Bcl-2. To investigate this further, we analyzed the -938 genotypes of the BCL-2 gene in 268 CLL patients and correlated data with treatment status, overall survival and known prognostic factors, for example, Binet stage, immunoglobulin heavy-chain variable (IGHV) mutational status and CD38 expression. In contrast to the recent report, the current cohort of CLL patients showed no differences either in time to treatment or overall survival in relation to usage of a particular genotype. In addition, no correlation was evident between the (-938C>A) genotypes and IGHV mutational status, Binet stage or CD38. Furthermore, the polymorphism did not appear to affect the Bcl-2 expression at the RNA level. Taken together, our data do not support the use of the (-938C>A) BCL-2 polymorphism as a prognostic marker in CLL and argue against its postulated role in modulating Bcl-2 levels.

The G(-248)A polymorphism in the promoter region of the Bax gene does not correlate with prognostic markers or overall survival in chronic lymphocytic leukemia

The G(-248)A polymorphism in the promoter region of the Bax gene was recently associated with low Bax expression, more advanced stage, treatment resistance and short overall survival in B-cell chronic lymphocytic leukemia (CLL), the latter particularly in treated patients. To investigate this further, we analyzed 463 CLL patients regarding the presence or absence of the G(-248)A polymorphism and correlated with overall survival, treatment status and known prognostic factors, for example, Binet stage, VH mutation status and genomic aberrations. In this material, similar allele and genotype frequencies of the Bax polymorphism were demonstrated in CLL patients and controls (n=207), where 19 and 21% carried this polymorphism, respectively, and no skewed distribution of the polymorphism was evident between different Binet stages and VH mutated and unmutated CLLs. Furthermore, no difference in overall survival was shown between patients displaying the G(-248)A polymorphism or not (median survival 85 and 102 months, respectively, P=0.21), and the polymorphism did not influence outcome specifically in treated CLL. Neither did the polymorphism affect outcome in prognostic subsets defined by VH mutation status or genomic aberrations. In conclusion, the pathogenic role and clinical impact of the Bax polymorphism is limited in CLL.

Attitude towards remission induction for elderly patients with acute myeloid leukemia influences survival

Combination chemotherapy may induce remission from acute myeloid leukemia (AML), but validated criteria for treatment of elderly are lacking. The remission intention (RI) rate for elderly patients, as reported to the Swedish Leukemia Registry, was known to be different when comparing the six health care regions, but the consequences of different management are unknown. The Leukemia Registry, containing 1672 AML patients diagnosed between 1997 and 2001, with 98% coverage and a median follow-up of 4 years, was completed with data from the compulsory cancer and population registries. Among 506 treated and untreated patients aged 70-79 years with AML (non-APL), there was a direct correlation between the RI rate in each health region (range 36-76%) and the two-year overall survival, with no censored observations (6-21%) (chi-squared for trend=11.3, P<0.001; r2=0.86, P<0.02, nonparametric). A 1-month landmark analysis showed significantly better survival in regions with higher RI rates (P=0.003). Differences could not be explained by demographics, and was found in both de novo and secondary leukemias. The 5-year survival of the overall population aged 70-79 years was similar between the regions. Survival of 70-79-year-old AML patients is better in regions where more elderly patients are judged eligible for remission induction.

Subcutaneous alemtuzumab vs ATG in adjusted conditioning for allogeneic transplantation: influence of Campath dose on lymphoid recovery, mixed chimerism and survival

Sixty-nine consecutive patients (median age 54 years) were prospectively enrolled in a single-institution protocol for allogeneic transplantation with adjusted non-myeloablative fludarabine-melfalan-based conditioning including cyclosporin A and MMF, and one of three modes of serotherapy. Thirty-one donors (45%) were unrelated. The first cohort of 29 had ATG (Thymoglobulin 2 mg/kg x 3 days), the subsequent 26 had Campath 30 mg x 3 days subcutaneously, and the final cohort of 14 had 30 mg Campath once. The groups were similar as regards age, diagnosis and risk factors. Campath-patients had no acute toxicity, fewer days with fever and antibiotics, and required fewer transfusions than ATG-treated patients. 3-d-Campath patients showed lower lymphocyte counts from day +4, and CD4+, CD8+, CD19+ and NK cells recovered slower than in ATG-treated patients. More Campath patients developed mixed chimerism that required DLI. 3-d-Campath induced more serious and opportunistic infections than ATG, which resulted in a greater non-relapse mortality and an impaired overall survival despite a low tumor-related mortality. The change of the Campath dosing schedule to one dose abrogated the deleterious effect of 3-d-Campath on immune recovery, severe infections and survival. Subcutaneous Campath is simple and provides strong immune suppression with no early toxicity, but dose limitation to 30 mg once is recommended.

Heterogeneity of nodularin bioaccumulation in northern Baltic Sea flounders in 2002

The cyanobacterial hepatotoxin nodularin is abundantly produced by the cyanobacterium Nodularia spumigena in the Baltic Sea during July-August. Nodularin is a potent hepatotoxin and a tumour promoter, distributed in various Baltic Sea environmental compartments, especially food webs involving mussels. Flounders receive nodularin through consumption of blue mussels. In this study nodularin concentrations in individual flounders (liver) were examined between July and September 2002 (six sample sets, four to 10 samples/set), providing information about contribution of sampling on estimates of bioaccumulation intensity. Toxin was determined using liquid chromatography/mass spectrometry (LC/MS) and enzyme-linked immunosorbent assay (ELISA). Additionally, liver histopathology was examined. Observed toxin concentrations were ND-390 microg kg(-1) dw (LC/MS) and 20-2230 microg kg(-1) dw (ELISA), with maximum concentrations in September (ELISA). The ELISA protocol generally resulted in higher, up to approximately 10-fold, toxin concentrations than LC/MS, with increasing difference toward September. This difference may have originated from different extraction solvents in LC/MS and ELISA, ion suppression in LC/MS, and temporal increase in nodularin metabolites detectable with ELISA. The differences in toxin concentrations between individual liver samples were considerable with relative standard deviation values of 20-154% (LC/MS) and 28-106% (ELISA). Since the precision of the ELISA method employed was <25% and that of LC/MS <10%, it can be concluded that the largest source of error in bioaccumulation estimates may be an inadequate number of samples. Although there were tissue lesions in several liver samples, occurrence of lesions was not related to toxin concentrations.

Autologous and allogeneic stem cell transplantation in adult ALL: the Swedish Adult ALL Group experience

Adult patients with acute lymphoblastic leukaemia (ALL) have been treated according to national protocols in Sweden since 1986. Stem cell transplantation (SCT) has been recommended in first remission for patients with risk factors for relapse, and for standard risk patients only after relapse. In this retrospective study, the results of autologous and allogeneic SCT in these populations were evaluated. In total, 187 patients with a median age of 34 years (17-66 years) underwent SCT. The 5-year disease-free survival (DFS), for all patients, was 26% (Confidence intervals (CI) 20-32%). The 5-year DFS was higher for patients transplanted in first remission 32% (CI 24-40%) compared to 14% (CI 5-23%; P<0.0001) in patients transplanted beyond first remission. No significant differences in DFS (P=0.06) were determined between autologous, related donor and unrelated donor SCT in the whole cohort. A lower relapse rate was counterbalanced by higher treatment-related mortality in patients undergoing allogeneic SCT. In Philadelphia-positive ALL, allogeneic SCT was superior to autologous SCT, with a 5-year DFS of 30% (CI 12-47%) vs 0% (P=0.04). Limited chronic graft-versus-host-disease (GVHD) was associated with an improved DFS of 53% (CI 38-69%) compared to no chronic GVHD of 22% (CI 10-36%; P=0.0008), indicating a clinically important graft-versus-leukaemia effect.

Early diagnosis of HIV-1 infection in infants in Dar es Salaam, Tanzania

OBJECTIVES

To evaluate two simple methods, an immune complex dissociation (ICD) p24 antigen assay and an HIV-1-specific IgA antibody assay, for the early demonstration of HIV-1 infection in infants, using the polymerase chain reaction (PCR) as the reference method.

DESIGN AND SETTING

Group A: 143 HIV-1-seropositive and 134 -seronegative mothers and their infants were recruited at delivery at the main hospital in Dar es Salaam, Tanzania. Group B: 26 HIV-PCR-positive hospitalized children in Dar es Salaam, 3-15 months old and suspected of having an HIV-related illness.

METHODS

Blood samples were taken from mothers and infants in group A at intervals during the children's first 24 months and once from each of the children in group B. Peripheral blood mononuclear cells were tested by nested PCR for viral DNA. Plasma samples were tested by the Coulter p24 antigen (ag) enzyme-linked immunosorbent assay (ELISA) after acid dissociation of p24 antigen-antibody complexes. All p24-ag-positive reactions were confirmed by neutralization. Viral specific IgA antibodies were demonstrated in plasma by a modified ELISA.

RESULTS

One hundred and sixty-three of 174 samples from seropositive mothers were PCR-positive (sensitivity 93.7%) and 612 of 614 samples from seronegative mothers and children of seronegative mothers were PCR-negative (specificity 99.7%). Twenty-nine of 145 (20.0%) children born to seropositive mothers were positive by PCR when tested during the first year of life. By use of both the p24 ag ELISA and the IgA antibody ELISA in combination, HIV-1 infection was detected in 9 of 17 (53%) PCR-positive children 1-8 weeks old, in 15 of 18 (83%) PCR-positive children 9-26 weeks old and in 23 of 24 (96%) PCR-positive children 27-52 weeks old. The specificities of the p24 ag ELISA and the IgA ELISA were 100%.

CONCLUSIONS

The p24 ag assay and the IgA antibody ELISA, when used in combination, had a high sensitivity and specificity for detection of HIV-1 infection in infants, especially in those above the age of 6 months.

Standard-dose anti-CD20 antibody rituximab has efficacy in chronic lymphocytic leukaemia: results from a Nordic multicentre study

OBJECTIVES

This prospective multicentre study was conducted to assess the efficacy of the monoclonal anti-CD20 antibody rituximab in patients with chronic lymphocytic leukaemia (CLL). Secondary objectives were defined as the tolerability and feasibility of rituximab in patients with CLL.

METHODS

Twenty-four heavily pretreated patients with CLL were treated with a standard dose of 375 mg m-2 of rituximab given once weekly for four doses.

RESULTS

The overall response rate was 35% and all the responses were partial as defined by the revised NCI criteria. In 17 (85%) of 20 patients with initially measurable peripheral lymph nodes the size of lymph nodes decreased by at least 50%, while an improvement of the bone marrow infiltration was observed only in two (11%) of 18 evaluable patients. The median duration of the overall response was 12.5 wk. Rituximab was relatively well tolerated. Although side-effects were common (75%) they were usually mild or moderate. There was only one grade 3 adverse event and no grade 4 events.

CONCLUSIONS

Standard-dose rituximab has activity in heavily pretreated patients with CLL, although the response is mainly limited to the lymph nodes and of short duration. Since rituximab has in vitro synergism with chemotherapeutic agents and is well tolerated by CLL patients, it is reasonable to investigate rituximab in combination with other treatments.

HIV counseling and testing of pregnant women in sub-Saharan Africa: experiences from a study on prevention of mother-to-child HIV-1 transmission in Dar es Salaam, Tanzania

The aim of this study was to determine the acceptability of HIV counseling and testing and participation in a mother-to-child HIV-1 transmission intervention study using antiretroviral therapy in Dar es Salaam, Tanzania, one of the sites for the Joint United Nations Program on AIDS (UNAIDS) multicenter Petra trial. HIV testing was offered to all pregnant women who visited three prenatal clinics in Dar es Salaam before 34 weeks' gestation. Group or individual pretest counseling was performed by trained midwives. Laboratory diagnosis of HIV infection was based on two sequential anti-HIV enzyme-linked immunosorbent assays. Posttest counseling was given 2 weeks later to women who wished to know their HIV status. HIV testing was offered to a total of 10,010 pregnant women from June 1996 to May 1998, of whom 76.4% (7647 of 10,010) agreed to be tested. The prevalence of HIV-1 infection was 13.7% (1050 of 7647). Overall, 68.1% (5205 of 7647) returned for their results. Of the HIV-1-seropositive respondents, 27.4% (288 of 1050) agreed to participate in the Petra trial after fulfilling the eligibility criteria. Only 16.7% (48 of 288) of the enrolled women disclosed their positive HIV serostatus to their sexual partners. The main reasons for not disclosing the HIV serostatus were fear of stigma and divorce. Sixty percent (29 of 48) of the informed sex partners agreed to be tested for HIV and 69% (20 of 29) tested HIV seropositive. Pregnancy recurrence rate was 4.4 per 100 women years (18 pregnancies during 408 women years of follow-up) with 10 of 18 (55.6%) women not wanting to carry the pregnancy to term. In conclusion, this information is useful in planning intervention programs for prevention of mother-to-child HIV-1 transmission and it shows that improvements are required in counseling.

Plexus avulsion and spinal cord injury increase the serum concentration of S-100 protein: an experimental study in rats

The possibility of using the presence of the glial-cell-derived protein S-100 in serum as a marker for neuronal damage caused by spinal cord injury and plexus avulsion injury was investigated in 144 adult rats. After a spinal cord injury had been induced at the thoracic level or a plexus avulsion injury at the lumbar level, blood samples were taken and analysed for S-100 protein by a monoclonal two-site immunoluminometric assay. The two types of neurotrauma changed the kinetics of serum S-100 in different ways. After spinal cord injury it rapidly increased and within 72 hours had reached a concentration about 5 times that of the control animals. Three peak concentrations occurred at 3, 12, and 72 hours, respectively, and differed significantly from those of the control group (p < 0.05). After six days the values had returned to normal. After lumbar plexus injury alone there was no significant increase in the concentration of S-100. These results suggest that the concentration of S-100 protein in serum may be used as an early diagnostic tool for detecting neuronal damage caused by spinal cord injury or plexus avulsion associated with damage to the root entry zone.

Corneal endothelial integrity in mice lacking extracellular superoxide dismutase

PURPOSE

To evaluate corneal endothelial morphology in mice without secreted extracellular superoxide dismutase (SOD) in normal ageing and in a lipopolysaccharide (LPS)-induced inflammation model and to measure the contents of SOD isoenzymes in the mouse cornea and the superoxide radical concentrations in corneas with and without extracellular SOD.

METHODS

The central corneal endothelium of wild-type and extracellular SOD-null mice were studied in micrographs at eight different ages and after a unilateral intravitreal injection of LPS, with the contralateral eye serving as the control. The activities of the SOD isoenzymes in the mouse cornea were determined with a direct assay, the superoxide radical concentration was assessed by lucigenin-induced chemiluminescence, and the extracellular SOD distribution was mapped with immunohistochemistry.

RESULTS

The activities of the cytosolic Cu- and Zn-containing SOD, the mitochondrial Mn-containing SOD and extracellular SOD were 4300, 15, and 340 U/g wet weight, respectively. Extracellular SOD was found in the epithelium, stroma, and endothelium. The concentration of extracellular superoxide radicals was doubled in extracellular SOD-null corneas, and the endothelial cell density decreased more with age in extracellular SOD-null than in wild-type control corneas. In the LPS-induced inflammation model, the cell density decreased more, and the cells became more irregular in extracellular SOD-null than in wild-type corneas.

CONCLUSIONS

In the mouse cornea, absence of extracellular SOD leads to a higher concentration of extracellular superoxide radicals, an enhancement in the spontaneous age-related loss of endothelial cells, and an increased susceptibility to acute inflammatory endothelial damage. Extracellular SOD is likely to have a protective role in the corneal endothelium.

In vitro photochemical cataract in mice lacking copper-zinc superoxide dismutase

We here evaluate cataract formation in mice lacking the cytosolic copper-zinc superoxide dismutase (CuZn-SOD) in an in vitro model using irradiation with visible light and riboflavin as a photosensitizing agent. Isolated, cultured lenses from wild-type and CuZn-SOD-null mice were irradiated for 1.5 h by a daylight fluorescent light after preincubation with 10 microM riboflavin for 24 h. Cataract formation was evaluated daily with digital image analysis and ocular staging, and after 5 d 86Rb uptake and water contents of the lenses were determined. Basal superoxide concentrations in freshly isolated lenses from wild-type and CuZn-SOD-null mice were determined with lucigenin-derived chemiluminescense, and enzymatic activities of all three SOD isoenzymes in the murine lens were determined with a direct spectrophotometric method. The cytosolic CuZn-SOD accounts for 90% of the total SOD activity of the murine lens. CuZn-SOD-null lenses showed a doubled basal superoxide concentration, and were more prone to develop photochemical cataract in the present model with more opacification, more hydration, and less 86Rb uptake than lenses from wild-type mice. We conclude that CuZn-SOD is an important superoxide scavenger in the lens, and that it may have a protective role against cataract formation.

Superoxide dismutase isoenzymes in the normal and diseased human cornea

PURPOSE

The human cornea, a tissue much exposed to oxidative stress, is rich in extracellular superoxide dismutase (SOD). In this study, the contents and distributions of the SOD isoenzymes in the normal human cornea were compared with those in corneas affected by keratoconus and bullous keratopathy.

METHODS

The central and peripheral parts of normal human corneas were analyzed separately. Central corneal buttons were obtained from patients with keratoconus and bullous keratopathy who were undergoing primary keratoplasty or retransplantation. SOD enzymatic activities were determined by a direct spectrophotometric method, and extracellular SOD and the cytosolic Cu- and Zn-containing SOD (CuZn-SOD) proteins were determined with ELISA and studied with immunohistochemistry.

RESULTS

The total SOD content, and particularly the extracellular SOD content, was lower in the central than in the peripheral normal cornea. CuZn-SOD and extracellular SOD were demonstrated in all three corneal layers. CuZn-SOD was found in cells, whereas extracellular SOD appeared to be localized on cell surfaces, in basal membranes, and in the stroma. In keratoconus, corneal levels of extracellular SOD were half those in the control corneas, whereas CuZn-SOD and the mitochondrial Mn-containing SOD levels were normal. In bullous keratopathy, apart from edematous dilution, SOD isoenzyme levels were essentially normal. In a remarkable finding, the same pattern in SOD isoenzyme levels as in the original disease was also found at retransplantation.

CONCLUSIONS

Extracellular SOD and CuZn-SOD show markedly different distribution patterns within the human cornea. Extracellular SOD activity in the central cornea is halved in keratoconus, compared with that in normal control corneas. The finding of a similar reduction at retransplantation in keratoconus suggests reduced corneal extracellular SOD synthesis in cells of the host as a cause of the low enzyme levels.

Substance P endopeptidase-like activity is altered in various regions of the rat central nervous system during morphine tolerance and withdrawal

In this study the level of a substance P endopeptidase (SPE)-like activity was measured in different regions of the rat central nervous system (CNS) after chronic administration of morphine. Male rats (200-220 g) were randomly divided into four groups. Two groups were injected (s.c.) with morphine (10 mg/kg) twice daily, whereas the other two received saline under identical conditions. After 8 days, when animals were completely tolerant to morphine, one of the morphine-treated groups and one group of saline-injected rats were given naloxone (s.c. 2 mg/kg). Withdrawal signs were observed and recorded. The enzyme activity was measured in extracts of the various CNS tissues by following the conversion of synthetic substance P (SP) to its N-terminal fragment SP(1-7) using a radioimmunoassay detecting this product. In discrete CNS areas including periaqueductal grey, spinal cord, substantia nigra and ventral tegmental area (VTA) a significant increase in enzyme activity was observed in the withdrawal group, while tolerant rats exhibited decreased SPE-like activity in the striatum (see Table 1). The enhanced enzyme activity during withdrawal is in agreement with our previous observation that the levels of SP(1-7) in rat brain are affected following naloxone precipitated withdrawal. In some tissues, including VTA, a correlation between the SPE-like activity and the intensity of the opioid abstinence was observed. Our result suggests that the elevated SPE-like activity is responsible for enhanced release of SP(1-7) in rats during morphine withdrawal, affirming a modulatory or regulative role of this enzyme in this state of opioid dependence.

Prevalence of HIV type 1 infection, associated clinical features and mortality among hospitalized children in Dar es Salaam, Tanzania

The aim of this study was to determine the prevalence of HIV-1 infection, the clinical spectrum of HIV-1-associated conditions and HIV-1-associated mortality among children hospitalized in the medical paediatric wards at Muhimbili Medical Centre (MMC), Dar es Salaam, Tanzania. All children admitted to the medical paediatric wards of MMC between August 1995 and January 1996 were eligible for the study. Testing for HIV antibodies was done using 2 consecutive enzyme linked immunosorbent assays (ELISAs). ELISA-reactive samples from children aged 18 months and below were further tested by a recently developed heat-denatured p24 antigen assay. The prevalence of HIV-1 infection among the 2015 children studied was 19.2%. When present for 14 days or more, fever, cough, diarrhoea, ear discharge, oral ulcers and skin rash were all significantly more common in HIV-1-infected than in HIV-uninfected children (p < 0.001). In the multivariate analysis cough, ear discharge, oropharyngeal ulcers and skin rash were found to be the most important symptoms. Clinical signs found to be significantly associated with HIV-1 infection in the univariate analysis were wasting, stunting, hair changes, oral thrush, oropharyngeal ulcers, lymphadenopathy, lung consolidation and lung crepitations (p < 0.001). In the multivariate analysis, oral thrush, lung crepitations, cervical lymphadenopathy, wasting and inguinal lymphadenopathy were found to be the most important signs. The 3 most common diagnoses in HIV-1-infected children were acute respiratory infection (ARI) (39.4%), malnutrition (38.1%) and tuberculosis (19.3%), while in HIV-uninfected children they were malaria (47.0%), ARI (25.0%) and malnutrition (16.1%). The mortality rate was 21.4% in HIV-1-infected children and 8.4% in HIV-uninfected children (p < 0.001). In conclusion, the prevalence of HIV-1 infection among hospitalized children at the main hospital in Dar es Salaam was high and associated with high mortality. Many symptoms and signs are indicative of HIV-1 infection, but appropriate laboratory testing is required for diagnosis.

High-performance liquid chromatographic separation of microcystins and nodularin, cyanobacterial peptide toxins, on C18 and amide C16 sorbents

Four C18 columns and a novel amide C16 column were assessed in the HPLC separation of eight microcystins and nodularin-R. Gradient mobile phases of acetonitrile combined with trifluoroacetic acid, formic acid or ammonium acetate were compared. Special attention was paid to the resolution of four possible coeluting microcystin pairs. Generally speaking, the acidic mobile phases were superior to the ammonium acetate-based mobile phase in terms of resolution and selectivity. The amide C16 column had the best overall performance and unique selectivity properties.

Biological effects after percutaneous absorption of thyrotropin-releasing hormone and its analogue M-TRH

Besides its well known endocrinological effects, thyrotropin-releasing hormone (TRH) has potential clinical value in the treatment of neurotrauma and various neurologic and psychiatric disorders. The aim of this study was to assess if transdermal delivery of TRH and its analogue, M-TRH, in the presence of enhancers, is an effective means for administration of the peptides. Using the in vitro diffusion cell method, the effect of ethanol and a terpene on the transdermal penetration of the peptides across full-thickness rat skin were studied. Steady-state permeability values for TRH and M-TRH were 8.7 +/- 2.2 and 6.7 +/- 1.4 microg/cm(2) h, respectively. The addition of 3 % terpene in combination with 47 % ethanol increased the penetration of TRH and M-TRH to 16.2 +/- 1.7 and 14.6 +/- 2.1 microg/cm(2) h, respectively. Rats were studied in vivo for release of thyroid-stimulating hormone (TSH) as a biologic effect after transdermally delivered peptide. Topical application of TRH and M-TRH induced an increase in TSH serum concentration from 0.32 +/- 0.09 ng/ml to 32.6 +/- 5.0 and 22.9 +/- 7.6 ng/ml, respectively, after 30 min. The addition of terpene and ethanol in combination with TRH or M-TRH, increased the TSH release to 43.0 +/- 3.8 and 48.4 +/- 4.0 ng/ml, respectively. It is concluded that, in the rat, peptides can be absorbed through the skin with retained biologic activity, and in amounts sufficient to elicit a physiological response.

Polyglycosylceramides recognized by Helicobacter pylori: analysis by matrix-assisted laser desorption/ionization mass spectrometry after degradation with endo-beta-galactosidase and by fast atom bombardment mass spectrometry of permethylated undegraded material

Human erythrocyte polyglycosylceramides (PGCs) are recognized by the gastric pathogen Helicobacter pylori and are based on a successively extended and highly branched N-acetyllactosamine core linked to ceramide and substituted by fucose and sialic acid. As a step in the identification of the binding epitope we earlier characterized intact PGCs by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS (Karlsson,H., Johansson,L., Miller-Podraza,H., and Karlsson,K-A. [1999] Glycobiology, 9, 765-778). In the present work, PGCs from human blood group O erythrocytes were digested with endo-ss-galactosidase (Bacterioides fragilis), an enzyme which cleaves the bond 3Galss1-4GlcNAc in linear but not branched poly-N-acetyllactosamine chains. The enzymatic digestion resulted in a mixture of neutral and sialic acid-containing glycolipids together with terminal and internal sequences of mainly neutral oligosaccharides. The products were analyzed by MALDI-TOF MS in both positive and negative ion mode which gave spectra where the ions could be assigned to structures of the neutral and acidic components, respectively. Among glycolipids found were [structure in text] where R could be H, Fuc or NeuAc. Also observed were structures as [structure in text] which indicated linear extension along both branches. Observed at higher masses were fully branched structures obtained by stepwise extension with [structure in text] where R could be H, Fuc or NeuAc. Most probably further branching may occur along both the (1-->3)- and the (1-->6)-linked branches to give a partly dendritic structure. Structures with more than one sialic acid substituted could not be observed in the MALDI spectrum. Complementary information of the terminal sequences was obtained by FAB-MS analysis of permethylated undegraded PGCs. High-temperature gas chromatography/mass spectrometry of reduced and permethylated products from enzyme hydrolysis documented that Fuc was present in a blood group O sequence, Fuc-Hex-HexN-. Fucose may be placed on short (monolactosamine) or longer branches, while sialic acid seems to be restricted to monolactosamine branches. The conclusion is that human erythrocyte PGCs display microheterogeneity within terminal and internal parts of the poly-N-acetyllactosamine chains. The first branch from the ceramide end may be located at the second or third Gal and possibly also on the first Gal. Other branches may occur on every N-acetyllactosamine unit in fully branched domains, or there may be linear extensions between branches resulting in incompletely branched structures. The extended linear sequences may be present in both 3- and 6-linked antennae. Terminal structures are based on one, two or maybe higher number of N-acetyllactosamine units.

Purification of substance P endopeptidase activity in the rat ventral tegemental area with the Akta-Purifier chromatographic system

The new chromatographic system Akta-Purifier 10 (Amersham-Pharmacia Biotech), scaled for preparative HPLC, was used for the purification of Substance P (SP) endopeptidase activity in the ventral tegemental area (VTA) of the rat brain. SP endopeptidase previously identified and purified from human cerebrospinal fluid has been found to degrade the neuroactive peptide SP in a specific pattern. In this study we have recovered SP endopeptidase from the rat VTA following a purification scheme involving homogenization (ultrasonication) and extraction of the excised tissue, size-exclusion chromatography (Superdex 75 HR), and ion-exchange chromatography (Resource Q). In this way we were able to achieve a purification factor of almost 7,500, based on specific activity. The obtained SP endopeptidase activity, was then subjected to characterization with regard to inhibition profile. The enzyme activity was monitored by following the conversion of SP to its N-terminal fragment SP(1-7) using a radioimmunoassay, specific for the heptapeptide product. On basis of inhibition profile it was possible to discern two different SP endopeptidase-like activities, one sensitive toward the protease inhibitor phosphoramidon (preparation A), and another non-sensitive to phosphoramidon or captopril (preparation B). The molecular masses of preparations A and B, as derived from sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were found to be 90,000 and 76,000, respectively. Our data suggest that the purified phosphoramidon sensitive endopeptidase activity may be an enzyme that plays a major role in the conversion of SP to its bioactive fragment SP(1-7) in the rat VTA. This is likely to be identical to the previously known neutral endopeptidase (EC 3.4.24.11). However, this study also demonstrates the existence of a distinct endopeptidase activity with properties in agreement with rat spinal cord SP endopeptidase. In the context of previously shown altered levels of SP(1-7) in the VTA during morphine withdrawal both purified enzyme activities may turn out to be responsible.

Purification of substance P endopeptidase (SPE) activity in human spinal cord and subsequent comparative studies with SPE in cerebrospinal fluid and with chymotrypsin

An enzyme activity capable of hydrolysing the neuroactive undecapeptide substance P (SP) between its Phe7-Phe8 residues was purified from the membrane-bound fraction of human spinal cords. The enzyme preparation yielded was compared with a previously described SP-hydrolysing enzyme from human cerebrospinal fluid (CSF) with regard to inhibition profile, protein chemical properties and kinetics. In addition, the results were compared with those of bovine pancreatic chymotrypsin (a serine protease that cleaves the carboxy-terminal side preferentially at hydrophobic amino acids). The SP peptidase activity was extracted from human spinal cords with 1% Triton X-100 in 20 mM Tris-HCI pH 7.8. After ion exchange chromatography (DEAE-Sepharose) where the enzyme activity was separated from other proteins by gradient elution, the pooled enzyme fraction was further purified by molecular sieving (Sephadex G-50). The enzyme activity was finally recovered by HPLC molecular sieving (Superdex 75 HR 10/30) using a new preparative system, AKTA-purifier, controlled by UNICORN software version 2.20.

Phase I clinical trials of aroA aroD and aroA aroD htrA attenuated S. typhi vaccines; effect of formulation on safety and immunogenicity

PBCC211, an aroA aroD derivative of S. typhi strain CDC10-80, was tested in phase I trials as a single dose typhoid fever vaccine. Three different vaccine preparations, reconstituted lyophilized bacteria, freshly grown bacteria or lyophilized bacteria reconstituted from sachets, were orally administered to a total of 86 adult volunteers. An aroA aroD htrA strain, PBCC222, was also tested in 38 volunteers. Formulation impacted on the determination of a safe and immunogenic dose; reconstituted lyophilized cultures required higher doses than the broth cultures to stimulate seroconversion. In general, doses which seroconverted the majority of group members produced undesirable symptoms regardless of attenuation or formulation. The inability to separate the presence of symptoms from achieving significant immunogenicity in these aroA aroD or aroA aroD htrA strains precludes their use as single dose typhoid vaccines in the formulations tested. Multiple doses of these strains at a lower, safe level may be effective as vectors for foreign antigens.

Enrichment of human brain proteins by heparin chromatography

Detection of low-abundance proteins is essential for the identification of novel drug targets by differential protein expression studies. We studied the enrichment of human fetal brain proteins by heparin chromatography. Total soluble brain proteins were fractionated on Heparin-Actigel and the fractions collected were analyzed by two-dimensional electrophoresis. The proteins were identified by matrix-assisted laser desorption ionization mass spectrometry. Approximately 300 protein spots were analyzed, representing 70 different polypeptides, 50 of which were bound to the heparin matrix. Eighteen brain proteins were identified for the first time. The proteins enriched by heparin chromatography include both minor and major components of the brain protein extract. The enriched proteins belong to several classes, including proteasome components, dihydropirimidinase-related proteins, T-complex protein 1 components and enzymes with various catalytic activities. The results include a two-dimensional map of the soluble brain proteins and a list of the proteins enriched by heparin chromatography. These may be useful in the design of protein purification protocols and in studies of neurological disorders.