Evaluation of sulphadoxine-pyrimethamine for intermittent preventive treatment of malaria in pregnancy: a retrospective birth outcomes study in Mansa, Zambia

Background

Intermittent preventive treatment of malaria in pregnancy (IPTp) with sulphadoxine-pyrimethamine (SP) decreases placental parasitaemia, thus improving birth outcomes. Zambian policy recommends monthly SP-IPTp doses given presumptively during pregnancy at each antenatal examination, spaced one month apart after 16 weeks of gestation. The effectiveness of SP-IPTp was evaluated in Zambia where a recent study showed moderate prevalence of Plasmodium falciparum parasites with genetic mutations that confer SP resistance.

Methods

HIV-negative women were enrolled at the time of delivery at two facilities in Mansa, Zambia, an area of high malaria transmission. Women were interviewed and SP exposure was determined by antenatal card documentation or self-reports. Using Poisson regression modelling, the effectiveness of SP-IPTp was evaluated for outcomes of parasitaemia (microscopic examination of maternal peripheral, cord, and placental blood films), maternal anaemia (Hb < 11 g/dl), placental infection (histopathology), and infant outcomes (low birth weight (LBW), preterm delivery, and small for gestational age) in women who took 0–4 doses of SP-IPTp.

Results

Participants included 435 women, with a median age of 23 years (range 16–44). Thirty-four women took zero doses of SP-IPTp, while 115, 142 and 144 women took one, two, or ≥ three doses, respectively. Multivariate Poisson regression models considering age, mosquito net usage, indoor residual spraying, urban home, gravidity, facility, wet season delivery, and marital status showed that among paucigravid women ≥ two doses of SP-ITPp compared to one or less doses was associated with a protective effect on LBW (prevalence ratio (PR) 0.33, 95% confidence interval (CI) 0.12–0.91) and any infection (PR 0.76, CI 0.58–0.99). Multivariate models considering SP-IPTp as a continuous variable showed a protective dose–response association with LBW (paucigravid women: PR 0.54, CI 0.33–0.90, multigravid women: PR 0.63, CI 0.41–0.97).

Conclusions

In Mansa, Zambia, an area of moderate SP resistance, ≥ two doses of SP-IPTp were associated with a protective effect from malaria in pregnancy, especially among paucigravid women. Each dose of SP-IPTp contributed to a 46 and 37% decrease in the frequency of LBW among paucigravid and multigravid women, respectively. SP-IPTp remains a viable strategy in this context.

Adherence to treatment with artemether-lumefantrine for uncomplicated malaria in rural Malawi

BACKGROUND

In 2007, Malawi replaced the first-line medication for uncomplicated malaria, sulfadoxine-pyrimethamine-a single-dose regimen-with artemether-lumefantrine (AL)-a 6-dose, 3-day regimen. Because of concerns about the complex dosing schedule, we assessed patient adherence to AL 2 years after routine implementation.

METHODS

Adults and children with uncomplicated malaria were recruited at 3 health centers. We conducted both pill counts and in-home interviews on medication consumption 72 hours after patients received AL. Complete adherence was defined as correctly taking all 6 AL doses, as assessed by pill count and dose recall. We used logistic regression to identify factors associated with complete adherence.

RESULTS

Of 386 patients, 65% were completely adherent. Patients were significantly more likely to be completely adherent if they received their first dose of AL as directly observed therapy at the health center (odds ratio [OR], 2.4; P < .01), received instructions using the medication package as a visual aid (OR, 2.5; P = .02), and preferred AL over other antimalarials (OR, 2.7; P < .001). In contrast, children <5 years of age were significantly less likely to be adherent (OR, 0.5; P = .05).

CONCLUSIONS

Adherence to AL treatment for uncomplicated malaria was moderate, and children, who are the most likely to die of malaria, were less adherent than adults. Efforts to improve adherence should be focused on this vulnerable group. Interventions including the introduction of child-friendly antimalarial formulations, direct observation of the first dose, use of the AL package as a visual aid for instructions, and enhancing patient preference for AL could potentially increase AL adherence and overall effectiveness.

Efficacy of sulphadoxine-pyrimethamine for intermittent preventive treatment of malaria in pregnancy, Mansa, Zambia

Background

Intermittent preventive treatment of malaria in pregnancy (IPTp) with sulphadoxine-pyrimethamine (SP) decreases adverse effects of malaria during pregnancy. Zambia implemented its IPTp-SP programme in 2003. Emergence of SP-resistant Plasmodium falciparum threatens this strategy. The quintuple mutant haplotype (substitutions in N51I, C59R, S108N in dhfr and A437G and K540E in dhps genes), is associated with SP treatment failure in non-pregnant patients with malaria. This study examined efficacy of IPTp-SP and presence of the quintuple mutant among pregnant women in Mansa, Zambia.

Methods

In Mansa, an area with high malaria transmission, HIV-negative pregnant women presenting to two antenatal clinics for the 1^st dose of IPTp-SP with asymptomatic parasitaemia were enrolled and microscopy for parasitaemia was done weekly for five weeks. Outcomes were parasitological failure and adequate parasitological response (no parasitaemia during follow-up). Polymerase chain reaction assays were employed to distinguish recrudescence from reinfection, and identify molecular markers of SP resistance. Survival analysis included those who had reinfection and incomplete follow-up (missed at least one follow-up).

Results

Of the 109 women included in the study, 58 (53%) completed all follow-up, 34 (31%) had incomplete follow-up, and 17 (16%) were lost to follow-up after day 0. Of those who had complete follow-up, 15 (26%, 95% confidence interval [CI] [16–38]) had parasitological failure. For the 92 women included in the survival analysis, median age was 20 years (interquartile range [IQR] 18–22), median gestational age was 22 weeks (IQR range 20–24), and 57% were primigravid. There was no difference in time to failure in primigravid versus multigravid women. Of the 84 women with complete haplotype data for the aforementioned loci of the dhfr and dhps genes, 53 (63%, 95% CI [50–70]) had quintuple mutants (two with an additional mutation in A581G of dhps). Among women with complete follow-up and quintuple mutants, 22% had parasitological failure versus 0% without (p = 0.44).

Conclusions

While underpowered, this study found 26% failure rates of SP given the moderate prevalence of the quintuple mutant haplotype. Despite the presence of resistance, SP retained some efficacy in clearing parasites in pregnant women, and may remain a viable option for IPTp in Zambia.

Characteristics of HIV care and treatment in PEPFAR-supported sites

BACKGROUND

The US President's Emergency Plan for AIDS Relief (PEPFAR) has supported the extension of HIV care and treatment to 2.4 million individuals as of September 2009. With increasing resources targeted toward rapid scale-up, it is important to understand the characteristics of current PEPFAR-supported HIV care and treatment sites.

METHODS

Forty-five sites in Botswana, Ethiopia, Nigeria, Uganda, and Vietnam were sampled. Data were collected retrospectively from successive 6-month periods through reviews of facility records and interviews with site personnel between April 2006 and March 2007. Facility size and scale-up rate, patient characteristics, staffing models, clinical and laboratory monitoring, and intervention mix were compared.

RESULTS

Sites added a median of 293 patients per quarter. By the evaluation's end, sites supported a median of 1649 HIV patients, 922 of them receiving antiretroviral therapy. Patients were predominantly adult (97.4%), and the majority (96.5%) were receiving regimens based on nonnucleoside reverse transcriptase inhibitors. The ratios of physicians to patients dropped substantially as sites matured. Antiretroviral therapy patients were commonly seen monthly or quarterly for clinical and laboratory monitoring, with CD4 counts being taken at 6-month intervals. One-third of sites provided viral load testing. Cotrimoxazole prophylaxis was the most prevalent supportive service.

CONCLUSIONS

HIV treatment sites scaled up rapidly with the influx of resources and technical support through PEPFAR, providing complex health services to progressively expanding patient cohorts. Human resources are stretched thin, and delivery models and intervention mix differ widely between sites. Ongoing research is needed to identify best-practice service delivery models.

Associations between peripheral Plasmodium falciparum malaria parasitemia, human immunodeficiency virus, and concurrent helminthic infection among pregnant women in Malawi

Approximately 2 billion persons worldwide are infected with schistosomiasis and soil-transmitted helminths (STH), many in areas where endemic malaria transmission coexists. Few data exist on associations between these infections. Nested within a larger clinical trial, primigravid and secundigravid women provided blood samples for human immunodeficiency virus (HIV) testing and peripheral malaria films and stool and urine for evaluation of STH and Schistosoma spp. during their initial antenatal clinic visit. The most common parasitic infections were malaria (37.6%), S. haematobium (32.3%), and hookworm (14.4%); 14.2% of women were HIV-infected. S. haematobium infection was associated with lower malarial parasite densities (344 versus 557 parasites/μL blood; P < 0.05). In multivariate analysis, HIV and hookworm infection were independently associated with malaria infection (adjusted odds ratio = 1.9 and 95% confidence interval = 1.2-3.0 for HIV; adjusted odds ratio = 1.9 and 95% confidence interval = 1.03-3.5 for hookworm). Concurrent helminthic infection had both positive and negative effects on malaria parasitemia among pregnant women in Malawi.

Effect of sulfadoxine-pyrimethamine resistance on the efficacy of intermittent preventive therapy for malaria control during pregnancy: a systematic review

CONTEXT

In malaria-endemic regions, strategies to control malaria during pregnancy rely on case management of malaria illness and anemia, and preventive measures such as insecticide-treated nets and intermittent preventive therapy (IPT).

OBJECTIVE

To determine the effect of increasing resistance to sulfadoxine-pyrimethamine on the efficacy of IPT during pregnancy in Africa.

DATA SOURCES AND STUDY SELECTION

The 6 databases of MEDLINE, EMBASE, SCOPUS, LILACS, Cochrane CENTRAL, and the trial register and bibliographic database of the Malaria in Pregnancy Library were searched for relevant studies regardless of language, published between 1966 and December 2006. The reference lists of all trials identified were searched and researchers were contacted about relevant data. Nine trials of IPT with sulfadoxine-pyrimethamine during pregnancy in Africa were identified and matched by year and location with treatment studies of sulfadoxine-pyrimethamine among symptomatic children.

DATA EXTRACTION

Data on the efficacy of IPT with sulfadoxine-pyrimethamine on placental and peripheral malaria, birth weight, and hemoglobin level/anemia were independently abstracted by 2 investigators. Sulfadoxine-pyrimethamine resistance was defined as the proportion of total treatment failures in symptomatic children by day 14.

DATA SYNTHESIS

Four trials compared 2-dose IPT with sulfadoxine-pyrimethamine to case management or placebo in women during their first or second pregnancy. The IPT reduced placental malaria (relative risk [RR], 0.48; 95% CI, 0.35-0.68), low birth weight (RR, 0.71; 95% CI, 0.55-0.92), and anemia (RR, 0.90; 95% CI, 0.81-0.99). The effect did not vary by sulfadoxine-pyrimethamine resistance levels (range, 19%-26%). Efficacy of IPT with sulfadoxine-pyrimethamine was lower among women using insecticide-treated nets. Three trials compared 2-dose with monthly IPT with sulfadoxine-pyrimethamine during pregnancy. Among HIV-positive women in their first or second pregnancy, monthly IPT resulted in less placental malaria (RR, 0.34; 95% CI, 0.18-0.64) and higher birth weight (mean difference, 112 g; 95% CI, 19-205 g) over the range of sulfadoxine-pyrimethamine resistance tested (8%-39%). Among HIV-negative women, there was no conclusive additional effect of monthly dosing (2 trials; 24% and 39% resistance).

CONCLUSIONS

In areas in which 1 of 4 treatments with sulfadoxine-pyrimethamine fail in children by day 14, the 2-dose IPT with sulfadoxine-pyrimethamine regimen continues to provide substantial benefit to HIV-negative semi-immune pregnant women. However, more frequent dosing is required in HIV-positive women not using cotrimoxazole prophylaxis for opportunistic infections.

Locally acquired mosquito-transmitted malaria: a guide for investigations in the United States

Recent outbreaks of locally acquired mosquito-transmitted malaria in the United States demonstrate the continued risk for reintroduction of the disease. Since 1957, when CDC's Malaria Branch started conducting malaria surveillance, 63 outbreaks have occurred, constituting 156 cases (annual range: 1-32) that were a result of locally acquired mosquitoborne transmission. This report describes the steps that should be taken to 1) investigate a case that might have been acquired locally, 2) prevent a small focus of malaria cases from becoming a source of sustained transmission, and 3) inform clinicians regarding the process of an investigation so they can effectively address concerns and questions from patients. Although these locally acquired mosquito-transmitted outbreaks frequently involve only a limited number of infected persons, they frequently raise concerns in the community and require substantial public health resources. For example, as a result of the most recent local outbreak of eight malaria cases in Florida in 2003, reverse 911 telephone calls (a community notification system) were made to approximately 300,000 residents; insect repellent, postcards, flyers, and posters in multiple languages were distributed; public announcements were made through the media and to schools and homeless shelters; and notifications were sent to local hospitals and physicians to inform residents of that community. When a local health department investigates a potential locally acquired mosquito-transmitted case, the systematic inquiry should include epidemiologic, environmental, and laboratory components. Local and state health departments inquiring about the proper approach to investigate and control a potential locally acquired case frequently request urgent assistance and tools from CDC. This report provides a starting point for such investigations to local and state health departments by providing them with the tools necessary to initiate an investigation.

Randomized trial of 2-dose versus monthly sulfadoxine-pyrimethamine intermittent preventive treatment for malaria in HIV-positive and HIV-negative pregnant women in Malawi

BACKGROUND

Intermittent preventive treatment during pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) decreases placental malaria parasitemia and associated maternal anemia, premature delivery, and low birth weight. However, the optimal regimen in the setting of a high prevalence of human immunodeficiency virus (HIV) infection remains unclear.

METHODS

In Malawi, where the efficacy of SP for the treatment of malaria in children is decreasing, we conducted a randomized, nonblinded study to compare the efficacy of monthly SP IPTp with a 2-dose regimen for the prevention of placental parasitemia in HIV-positive and -negative primigravid and secundigravid women.

RESULTS

Of HIV-positive women, 7.8% who received monthly SP had placental malaria, compared with 21.5% of those who received 2-dose SP (relative risk [RR], 0.36 [95% confidence interval {CI}, 0.17-0.79]). Of HIV-negative women, 2.3% who received monthly SP and 6.3% who received 2-dose SP had placental malaria (RR, 0.37 [95% CI, 0.11-1.19]). Less than 1% of women reported adverse drug reactions, with no increase in HIV-positive women or those who received monthly SP.

CONCLUSIONS

In HIV-positive pregnant women, monthly SP IPTp is more efficacious than a 2-dose regimen in preventing placental malaria. The study also demonstrates the continued efficacy of SP for the prevention of placental malaria, even in the face of its decreasing efficacy for the treatment of malaria in children. In areas with intense transmission of falciparum malaria and a high prevalence of HIV infection, monthly SP IPTp should be adopted.

Effects of gastroesophageal reflux on the oral cavity

The effects of chronic exposure of the oral cavity to gastric acid can be many and varied. Soft tissue symptoms (nonspecific burning and sensitivity) have been mentioned in the literature, but pathognomonic soft tissue lesions have not been documented. Dental erosion can be considered to be the predominant oral manifestation of gastroesophageal reflux disease. Erosion begins with subtle changes in the surface enamel and can progress to severe loss of tooth substance. Because the causes of such tooth lesions may be multifactorial, combining the effects of erosion, attrition, and abrasion and because of the subtle changes present in the beginning stages of such lesions, diagnosis may be difficult. Although the basic mechanism of erosion in gastroesophageal reflux patients is the dissolution of enamel and dentin due to acid exposure, a multitude of other factors can modify the effects of gastric acid. Salivary parameters, in particular, may play an important role in affecting oral pH after reflux episodes. Once dental erosion is diagnosed, thorough evaluation is necessary to document the extent of damage and to detect a cause, which may have both intrinsic and extrinsic components. Treatment goals include eliminating the causes of acid exposure, preventing the effects of acid exposure when it is not controllable, treating symptoms of soft tissue irritation and dental erosion, and restoring the dentition to an esthetically and functionally acceptable level.

Dental evaluation in bone marrow transplantation

In the case presented, thorough radiographic and clinical examinations would have precluded misinforming the patient and prevented a six-week delay of the bone marrow transplant. The patient's ill feeling was generated because of confusion about the recommended dental treatment. This was unfortunate, given the considerable physical and emotional stress that these patients endure under the best of circumstances. Because of the severity of immunosuppression before and (for three months) after transplantation, and the life-threatening nature of oral infection, elimination of oral infection is paramount for successful BMT. This can only be achieved by adequate diagnosis and prompt, aggressive dental treatment.

Dental erosion and acid reflux disease

OBJECTIVE

To determine the relation between gastroesophageal reflux disease and dental erosion using ambulatory 24-hour esophageal pH testing.

DESIGN

Cross-sectional observational study.

SETTING

Tertiary referral center.

PATIENTS

The dental group consisted of 12 patients with idiopathic dental erosion who were identified by dentists and screened for gastroesophageal reflux disease using 24-hour pH testing. The gastroenterology group consisted of 30 patients who had 24-hour pH testing in the esophageal laboratory and who were referred for dental evaluation (10 did not have reflux, 10 had distal reflux, and 10 had proximal reflux).

MEASUREMENTS

24-hour esophageal pH monitoring using a pH probe in the distal and proximal esophagus. Complete dental examination with particular attention to the presence and severity of dental erosion; plaque; gingival damage; and decayed, missing, and filled teeth. Analysis of saliva for pH, flow rates, buffering capacity, and calcium and phosphorus levels. Standardized questionnaire to ascertain possible causes of dental erosion and presence of reflux symptoms.

RESULTS

Ten of the 12 patients in the dental group (83% [95% CI, 52% to 98%]) had gastroesophageal reflux on esophageal pH monitoring. Nine had distal and 7 had proximal reflux. Seven had reflux in the upright position only, 1 had reflux in the supine position only, and 2 had both upright and supine reflux. No saliva abnormalities were found. Ten patients had typical symptoms of gastroesophageal reflux, but dietary or mechanical problems that may have been causing dental erosion were not identified. In the gastroenterology group, upright reflux was seen in 5 of the 10 patients with distal reflux and in all 10 patients with proximal reflux. In addition, 40% of patients in the gastroenterology group (12 of 30) had dental erosion (4 of the 10 with distal reflux [40%], 7 of the 10 with proximal reflux [70%], and only 1 of the 10 without reflux [10%]; P = 0.02 for those with reflux compared with those without reflux). The cumulative dental erosion score correlated with proximal upright reflux when all 24 study patients with erosion were analyzed (r = 0.55 [P < 0.01]); this correlation was even stronger in the subgroup of 12 patients with abnormal amounts of proximal upright reflux (r = 0.84 [P = 0.001]).

CONCLUSION

Dental erosion is a common finding in patients with gastroesophageal reflux disease and should be considered an atypical manifestation of this disease.

Radiographic evaluation of occlusal caries: effect of training and experience

The purpose of this study was to investigate what effect differing levels of didactic education and clinical experience have on the ability to diagnose occlusal caries from radiographs. Freshman and senior dental students and dental school faculty were asked to evaluate bitewing radiographs for the presence of occlusal caries and for a recommendation for restorative treatment. The agreement between histologic and radiographic diagnosis was assessed by calculating sensitivity, specificity, accuracy, and interexaminer agreement. It was concluded that dental students and faculty did differ in their abilities to evaluate radiographs for occlusal caries, and that education and clinical experience especially affected interexaminer agreement.

Tooth erosion: an unusual case

A case of tooth erosion due to prolonged exposure to acidic pool water has been presented. Dentists and swimmers must be aware of the detrimental dental effects associated with prolonged exposure to improperly maintained pool water, and what measures can be taken to prevent such effects.

Shear bond strengths of composite to chlorhexidine-treated enamel

This study determined the shear bond strength (SBS) of composite bonded to chlorhexidine-treated enamel and untreated enamel. Fifty human molars were mounted in cold- cure acrylic and the superficial enamel of the buccal or lingual surface was exposed using 600-grit silicon carbide paper. During the experimental protocol, the control group (n = 25) and the experimental group (n = 25) were stored in distilled water at 37 degrees C. The experimental group was immersed in 0.12% chlorhexidine gluconate for 1 minute, 4 times daily, for 7 days. Prisma APH composite was then bonded to all samples following acid etching for 30 seconds, and the SBS was determined. Shear bond strengths for the control (13.23 +/- 3.22 MPa) and the experimental (13.67 +/- 4.59 MPa) groups were not significantly different using a t-test. The result may be attributed to either a lack of effect of chlorhexidine or to the acid etch which dissolves the affected superficial enamel leaving an unaffected substrate for bonding.

Effect of immune bovine milk on Streptococcus mutans in human dental plaque

The use of a mouthrinse of bovine milk containing antibodies to Streptococcus mutans resulted in an initial reduction in the numbers of recoverable Strep. mutans in a group of 9 individuals. Ten volunteers who used control bovine milk that contained no antibody activity to Strep. mutans had variable levels of plaque Strep. mutans. In addition, after culture on Mitis Salivarius and Gold's agar, the plaque Strep. mutans from subjects who used the immune bovine milk rinse formed smaller colonies than those from pre-treatment plaque and from all plaque samples of subjects who used the control rinse.

Function of anti-Streptococcus mutans antibodies: inhibition of virulence factors and enzyme neutralization

The levels of parotid salivary IgA and serum IgG antibodies from dental caries-resistant (CR) and caries-susceptible (CS) individuals to Streptococcus mutans antigens were determined. In general, the levels of salivary IgA and serum IgG antibodies to S. mutans antigens were significantly higher in CR subjects than in CS individuals. There were significantly higher levels of IgA2, but not IgA1, salivary antibodies to S. mutans whole cells in CR subjects than in CS individuals. These results led us to investigate the functional effects parotid saliva and sera containing these antibodies had on several factors associated with S. mutans virulence. Parotid saliva and sera from CR subjects significantly inhibited S. mutans growth, adherence, acid production, glucosyltransferase and glucose-phosphotransferase activities to a greater extent than saliva and sera from CS individuals. The data suggest that neutralization of S. mutans enzymes and inhibition of S. mutans virulence factors by saliva and serum may be responsible for the lower numbers of carious lesions in CR subjects.

Protective secretory immunoglobulin A antibodies in humans following oral immunization with Streptococcus mutans

Ingestion of a vaccine containing killed Streptococcus mutans, originally isolated from each volunteer, daily for 10 consecutive days induced increased levels of specific secretory immunoglobulin A (sIgA) antibodies to S. mutans cells and two cell surface proteins, glucosyltransferase and surface antigen I/II, in parotid saliva and tears of four healthy males and in parotid saliva, tears, colostrum, and milk of a pregnant woman. In addition, these antibodies inhibited glucosyltransferase activity. Both IgA1 and IgA2 antibodies were induced. The levels of IgA antibodies in all secretions remained significantly above preimmunization levels for more than 50 days after oral administration of antigen. A second series of immunizations for 7 consecutive days resulted in even higher levels of sIgA antibodies, which peaked earlier and persisted longer than those observed after the primary immunizations. No increase in levels of antibodies in serum were detected in any subject. Antibodies reactive with human heart and kidney antigens could not be detected in saliva, tears, colostrum, milk, or serum samples collected at any time during the immunization regimen. The numbers of viable S. mutans organisms in dental plaque and whole saliva decreased after each series of immunizations, which correlated with increased levels of IgA antibodies in saliva, suggesting that IgA antibodies in saliva were responsible for the reduced adherence of this bacterium. These results indicate that ingested S. mutans antigen induces secretion of specific IgA1 and IgA2 antibodies in saliva, tears, colostrum, and milk, providing further evidence for the existence of a common mucosal immune system.

Protection of gnotobiotic rats against dental caries by passive immunization with bovine milk antibodies to Streptococcus mutans

A multivalent vaccine consisting of whole cell antigens of seven strains, representing four serotypes (b, c, d and g), of mutans streptococci was used to hyperimmunize a group of cows. Serum samples from these animals contained immunoglobulin G1 (IgG1) antibody activity to seven serotypes (a to g) of mutans streptococci. Whey obtained from the animal with the highest serum antibody activity, which also contained high levels of IgG1 antibody, was used in passive caries immunity studies. Gnotobiotic rats monoinfected with Streptococcus mutans MT8148 serotype c or Streptococcus sobrinus OMZ176 (d) or 6715 (g) and provided a caries-promoting diet containing immune whey had lower plaque scores, numbers of streptococci in plaque, and degree of caries activity than similarly infected animals given a diet containing control whey obtained from nonimmunized cows. To establish the nature of the protective component(s) present in the immune whey, an ultrafiltrate fraction of the whey was prepared. This preparation contained higher levels of IgG1 anti-S. mutans antibody activity than the immune whey. Rats monoinfected with S. mutans MT8148 and provided with a diet supplemented with 0.1% of this fraction exhibited a degree of caries protection similar to that seen in animals provided a diet containing 100% immune whey. In fact, a diet containing as little as 0.01% of the ultrafiltrate fraction gave some degree of protection against oral S. mutans infection. The active component in the immune whey was the IgG1 anti-S. mutans antibody, since rats monoinfected with S. mutans MT8148 and provided a diet supplemented with purified immune whey IgG1 had significantly reduced plaque scores, numbers of S. mutans in plaque, and caries activity compared with control animals. Prior adsorption of the IgG fraction with killed S. mutans MT8148 whole cells removed antibody activity and abrogated caries protection.

Salivary immunoglobulin A and serum antibodies to Streptococcus mutans ribosomal preparations in dental caries-free and caries-susceptible human subjects

Caries-free subjects or individuals with low caries susceptibility exhibited significantly higher (P less than 0.001) levels of naturally occurring salivary immunoglobulin A (IgA) and serum IgG, IgA, and IgM antibodies to a Streptococcus mutans ribosomal preparation than subjects with high caries susceptibility. Absorption of saliva and serum samples with S. mutans ribosomal preparations, but not with other S. mutans antigens or with Escherichia coli and Neisseria gonorrhoeae ribosomal preparations, removed the antibody activity. Absorption with Streptococcus sanguis ribosomes and NH4Cl-washed S. mutans ribosomes partially removed the anti-S. mutans ribosome antibody activity. These results provide evidence that naturally occurring salivary and serum antibodies to the S. mutans ribosomal preparation correlate with susceptibility to dental caries.

Tooth extraction by orthodontic force after radiation therapy: report of case

This report presents a therapeutic approach to orthodontic tooth extraction in a patient at high risk for the development of osteoradionecrosis with conventional techniques. The rationale for this procedure is discussed in detail, combining principles of radiation biology, clinical radiation therapy, and biomechanics of tooth movement.

Prevention of Streptococcus mutans colonization by salivary IgA antibodies

The levels of salivary and serum IgA, IgG, and IgM antibodies to the seven serotypes (a-g) of Streptococcus mutans were established in 12 laboratory volunteers using a sensitive enzyme-linked immunosorbent assay. Salivary IgA antibody levels to the serotype c organism were significantly lower (P less than 0.005) than antibody levels to the other six serotypes of S. mutans. Similar results were found with a purified S. mutans serotype c carbohydrate. Serum IgG and IgM antibody titers to the serotype c whole cells were significantly higher (P less than 0.05) than to four other S. mutans serotypes (a, e-g). The abilities of S. mutans serotypes c and d to colonize molar tooth surfaces were examined in eight volunteers. S. mutans serotype d was cleared from the tooth surfaces within 24 hr of challenge, whereas S. mutans serotype c was detected in six of the eight volunteers after 2 weeks and in three of eight after 3 weeks. These results provide additional evidence for the role of salivary IgA antibodies in regulating S. mutans infection and suggest that the low levels of salivary IgA antibodies to S. mutans serotype c may contribute to the predominance of this serotype in the U.S. population.