Abstract 35: Novel genetic and clinical determinants of Constitutional Mismatch Repair Deficiency syndrome: Report from the CMMRD consortium

Purpose: Constitutional mismatch repair deficiency (CMMRD) is a devastating cancer predisposition syndrome affecting children born with two mutated alleles in one of four mismatch repair genes. Data regarding clinical manifestations, molecular screening tools and management are limited.

Patients and methods: We established an international CMMRD consortium and collected comprehensive clinical and genetic data. Molecular diagnosis of tumor and germline biospecimens were performed. A surveillance protocol was developed and implemented.

Results: Overall, 27/30 (90%) of children with CMMR-D developed 48 different tumors. While childhood CMMR-D related tumors were observed in all families, Lynch related tumors in adults were observed in only 2/17 families (p<0.0001). All children with CMMR-D had cafe-au-lait spots and 14/17 families were consanguineous.

We detected 17 different germline MMR mutations. These included mutations in PMS2(8), MSH6(7) and MLH1(2). Importantly 7/17 mutations were previously unreported. Brain tumors were the most common cancers reported (44%) followed by gastrointestinal (33%) and hematological malignancies (17%). Importantly, 14 (29%) of these were low grade and respectable cancers. Tumor immunohistochemistry was 100% sensitive and specific in diagnosing MMR deficiency of the corresponding gene while microsatellite instability was neither sensitive nor specific as a diagnostic tool (p<0.0001). Furthermore, screening of normal tissue by immunohistochemistry correlated with genetic confirmation of CMMR-D. The surveillance protocol detected 43 lesions which included asymptomatic malignant gliomas and gastrointestinal carcinomas. All tumors were amenable to complete resection and all patients undergoing surveillance are alive.

Conclusion: CMMR-D is a highly penetrant syndrome where family history of cancer may not be contributory. Screening tumors and normal tissues using immunohistochemistry for abnormal expression of MMR gene products helps in diagnosis and early implementation of surveillance for these children.

Citation Format: Doua Bakry, Brittany Campbell, Carol Durno, Melyssa Aronson, Qasim Alharbi, Musa Alharbi, Shlomi Constantini, Aaron Pollett, Shay Ben-Shachar, Jordan Lerner-Ellis, Steven Gallinger, Ronit Elhasid, Roula Farah, Ibrahim Qaddoumi, Matthew Mistry, Ramyar Lily, Steve Keiles, Rina Dvir, Derek Stephens, David Malkin, Eric Bouffet, Cynthia Hawkins, Uri Tabori. Novel genetic and clinical determinants of Constitutional Mismatch Repair Deficiency syndrome: Report from the CMMRD consortium. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Susceptibility and Cancer Susceptibility Syndromes; Jan 29-Feb 1, 2014; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(23 Suppl):Abstract nr 35. doi:10.1158/1538-7445.CANSUSC14-35

Genetic and clinical determinants of constitutional mismatch repair deficiency syndrome: report from the constitutional mismatch repair deficiency consortium

BACKGROUND

Constitutional mismatch repair deficiency (CMMRD) is a devastating cancer predisposition syndrome for which data regarding clinical manifestations, molecular screening tools and management are limited.

METHODS

We established an international CMMRD consortium and collected comprehensive clinical and genetic data. Molecular diagnosis of tumour and germline biospecimens was performed. A surveillance protocol was developed and implemented.

RESULTS

Overall, 22/23 (96%) of children with CMMRD developed 40 different tumours. While childhood CMMRD related tumours were observed in all families, Lynch related tumours in adults were observed in only 2/14 families (p=0.0007). All children with CMMRD had café-au-lait spots and 11/14 came from consanguineous families. Brain tumours were the most common cancers reported (48%) followed by gastrointestinal (32%) and haematological malignancies (15%). Importantly, 12 (30%) of these were low grade and resectable cancers. Tumour immunohistochemistry was 100% sensitive and specific in diagnosing mismatch repair (MMR) deficiency of the corresponding gene while microsatellite instability was neither sensitive nor specific as a diagnostic tool (p<0.0001). Furthermore, screening of normal tissue by immunohistochemistry correlated with genetic confirmation of CMMRD. The surveillance protocol detected 39 lesions which included asymptomatic malignant gliomas and gastrointestinal carcinomas. All tumours were amenable to complete resection and all patients undergoing surveillance are alive.

DISCUSSION

CMMRD is a highly penetrant syndrome where family history of cancer may not be contributory. Screening tumours and normal tissues using immunohistochemistry for abnormal expression of MMR gene products may help in diagnosis and early implementation of surveillance for these children.

Cancer incidence in the United Kingdom: projections to the year 2030

Background:

Projections of cancer incidence are important for planning health services and to provide a baseline for assessing the impact of public health interventions.

Methods:

Rates estimated from smooth function age–period–cohort modelling of cancer incidence data from Great Britain 1975 to 2007 are extrapolated to 2030 and applied to UK population projections. Prostate and breast cancer projections take into account the effect of screening.

Results:

Overall rates of cancer are projected to be stable over the next 20 years, but this masks individual changes. In both sexes, age-standardised rates of cancers of the stomach, larynx, bladder and leukaemia are projected to fall by ⩾1% per year, whereas cancers of the lip, mouth and pharynx (ICD-10 C00-C14) and melanoma are projected to increase by ⩾1% per year. The growing and aging populations will have a substantial impact: numbers of cancers in men and women are projected to increase by 55% (from 149 169 to 231 026) and 35% (from 148 716 to 200 929), respectively, between 2007 and 2030. The model used yields similar results to those of Nordpred, but is more flexible.

Conclusion:

Without new initiatives for smoking and obesity reduction, the number of cancers in the United Kingdom will increase substantially reflecting the growing and aging populations.

Dose-response effects of TPI ASM8 in asthmatics after allergen

BACKGROUND

TPI ASM8 contains two modified antisense oligonucleotides (AON) targeting the beta subunit (β(c) ) of the IL-3, IL-5, GM-CSF receptors and the chemokine receptor CCR3. A previous study suggested that TPI ASM8 had broader effects than just inhibition of eosinophils in asthmatics.

OBJECTIVE

We assessed whether TPI ASM8 caused a dose-dependent attenuation in the inflammatory and physiological changes after inhaled allergen challenge (AIC).

METHODS

This single-center, open-label, stepwise-ascending dose study was conducted in fourteen stable, mild allergic asthmatics. Following placebo AIC, subjects underwent AIC after 4 days treatment with 1, 2, and 4 mg BID and finally 8 mg once daily (OD) of TPI ASM8, inhaled via the I-Neb™ nebuliser. Treatments were separated by 2-3-week washout periods.

RESULTS

TPI ASM8 was safe and well tolerated at all doses. TPI ASM8 8 mg OD reduced eosinophils in sputum after AIC (by 60.9% at 7 h and 68.4% at 24 h post-AIC, P=0.016 and P=0.007, respectively). Additionally, TPI ASM8 8 mg OD significantly attenuated the early and late airway responses as shown by the reduction in the area under the curve by 45% (P=0.016) and 59%, (P=0.0015), respectively, the increase in eosinophil cationic protein (ECP) by up to 57% (P=0.021), and airway responsiveness to methacholine by more than 1 doubling dose (P=0.012). A dose-response relationship was noted, and efficacy was maintained with once per day administration.

CONCLUSIONS

TPI ASM8 attenuated a broad range of inflammatory and physiological changes after AIC, suggesting that CCR3, IL-3, and GM-CSF also are important targets for the management of asthma.

A cross-laboratory comparison of expression profiling data from normal human postmortem brain

Expression profiling of post-mortem human brain tissue has been widely used to study molecular changes associated with neuropsychiatric diseases as well as normal processes such as aging. Changes in expression associated with factors such as age, gender or postmortem interval are often more pronounced than changes associated with disease. Therefore in addition to being of interest in their own right, careful consideration of these effects are important in the interpretation of disease studies. We performed a large meta-analysis of genome-wide expression studies of normal human cortex to more fully catalogue the effects of age, gender, postmortem interval and brain pH, yielding a "meta-signature" of gene expression changes for each factor. We validated our results by showing a significant overlap with independent gene lists extracted from the literature. Importantly, meta-analysis identifies genes which are not significant in any individual study. Finally, we show that many schizophrenia candidate genes appear in the meta-signatures, reinforcing the idea that studies must be carefully controlled for interactions between these factors and disease. In addition to the inherent value of the meta-signatures, our results provide critical information for future studies of disease effects in the human brain.

Management of the oral manifestations of HIV/AIDS by traditional healers and care givers

In many communities of South Africa, traditional healers are often the only means of health care delivery available. The level of knowledge and ability to recognize oral lesions of 32 traditional healers and 17 care-givers were assessed after a two-day workshop. The data collection instrument was a structured questionnaire, complimented by enlarged clinical photographs of the common oral manifestations of HIV/AIDS. Prior to the workshop, 46 (93.9%) of the 49 respondents had never had any formal information on oral health and 43 (87.8%) were unfamiliar with the symptoms of oral diseases. Thirty-five (71.4%) recognized bleeding gums from A4-size photographs and 11 (22.4%) recognized oral thrush. The recognition of other oral manifestations of HIV/AIDS were; oral hairy leukoplakia (41.0%), angular cheilitis (43.6%), herpes virus infection (56.4%), oral ulcerations (56.8%), and in children, parotid enlargement (27.3%), and moluscum contagiosum (56.8%). Traditional healers and caregivers constitute an untapped resource with enormous potential. A positive bridge should be built to link traditional healing with modem medicine in the struggle against HIV/AIDS.

Oral health knowledge and original practices of African traditional healers in Zonkizizwe and Dube, South Africa

Self reported oral health knowledge and practices of 83 traditional healers in Zonkizizwe (56) and Dube (27) Gauteng Province, South Africa were carried out using a questionnaire and clinical photographs of common oral conditions. The mean age for the total group was 49.5 with 35 males and 48 females. Although only 17 of the healers were members of a professional association, many indicated their willingness to join one. 40 (71%) of healers in Zonkizizwe kept written client records but far fewer 3 (11%) did so in Dube. More than 90% of traditional healers from both areas correctly identified photographs of gingival inflammation, dental caries and oral candidiasis. Over 50% of healers from both areas had patients who presented with mouth problems. Ninety percent of healers in Zonkizizwe referred patients to the formal health care sector but less than 50% in Dube did so. A vast majority of healers gave oral health advice to their patients, many of whom gave specific tooth brush instruction. The study provides an initial understanding of the practices of healers regarding oral health.

Serum and salivary IgA antibody responses to Saccharomyces cerevisiae, Candida albicans and Streptococcus mutans in orofacial granulomatosis and Crohn's disease

Orofacial granulomatosis (OFG) is a condition of unknown aetiology with histological and, in some cases, clinical association with Crohn's disease (CD). However, the exact relationship between OFG and CD remains uncertain. The aim of this study was to determine whether OFG could be distinguished immunologically from CD by comparing non-specific and specific aspects of humoral immunity in serum, whole saliva and parotid saliva in three groups of patients: (a) OFG only (n = 14), (b) those with both oral and gut CD (OFG + CD) (n = 12) and (c) CD without oral involvement (n = 22) and in healthy controls (n = 29). Non-specific immunoglobulin (IgA, SigA, IgA subclasses and IgG) levels and antibodies to whole cells of Saccharomyces cerevisiae, Candida albicans and Streptococcus mutans were assayed by enzyme-linked immunosorbent assay (ELISA) in serum, whole saliva and parotid saliva. Serum IgA and IgA1 and IgA2 subclasses were raised in all patient groups (P < 0.01). Salivary IgA (and IgG) levels were raised in OFG and OFG + CD (P < 0.01) but not in the CD group. Parotid IgA was also raised in OFG and OFG + CD but not in CD. The findings suggest that serum IgA changes reflect mucosal inflammation anywhere in the GI tract but that salivary IgA changes reflect involvement of the oral cavity. Furthermore, the elevated levels of IgA in parotid saliva suggest involvement of the salivary glands in OFG. Serum IgA antibodies to S. cerevisiae were raised markedly in the two groups with gut disease while serum IgA (or IgG) antibodies to C. albicans were elevated significantly in all three patient groups (P < 0.02). No differences were found with antibodies to S. mutans. Whole saliva IgA antibodies to S. cerevisiae (and C. albicans) were raised in the groups with oral involvement. These findings suggest that raised serum IgA antibodies to S. cerevisiae may reflect gut inflammation while raised SIgA antibodies to S. cerevisiae or raised IgA or IgA2 levels in saliva reflect oral but not gut disease. Analysis of salivary IgA and IgA antibodies to S. cerevisiae as well as serum antibodies in patients presenting with OFG may allow prediction of gut involvement.

Molecular correlates of the M-current in cultured rat hippocampal neurons

M-type K(+) currents (I(K(M))) play a key role in regulating neuronal excitability. In sympathetic neurons, M-channels are thought to be composed of a heteromeric assembly of KCNQ2 and KCNQ3 K(+) channel subunits. Here, we have tried to identify the KCNQ subunits that are involved in the generation of I(K(M)) in hippocampal pyramidal neurons cultured from 5- to 7-day-old rats. RT-PCR of either CA1 or CA3 regions revealed the presence of KCNQ2, KCNQ3, KCNQ4 and KCNQ5 subunits. Single-cell PCR of dissociated hippocampal pyramidal neurons gave detectable signals for only KCNQ2, KCNQ3 and KCNQ5; where tested, most also expressed mRNA for the vesicular glutamate transporter VGLUT1. Staining for KCNQ2 and KCNQ5 protein showed punctate fluorescence on both the somata and dendrites of hippocampal neurons. Staining for KCNQ3 was diffusely distributed whereas KCNQ4 was undetectable. In perforated patch recordings, linopirdine, a specific M-channel blocker, fully inhibited I(K(M)) with an IC(50) of 3.6 +/- 1.5 microM. In 70 % of these cells, TEA fully suppressed I(K(M)) with an IC(50) of 0.7 +/- 0.1 mM. In the remaining cells, TEA maximally reduced I(K(M)) by only 59.7 +/- 5.2 % with an IC(50) of 1.4 +/- 0.3 mM; residual I(K(M)) was abolished by linopirdine. Our data suggest that KCNQ2, KCNQ3 and KCNQ5 subunits contribute to I(K(M)) in these neurons and that the variations in TEA sensitivity may reflect differential expression of KCNQ2, KCNQ3 and KCNQ5 subunits.

Dominant-negative subunits reveal potassium channel families that contribute to M-like potassium currents

M-currents are K+ currents generated by members of the KCNQ family of K+ channels (Wang et al., 1998). However, in some cells, M-like currents may be contaminated by members of other K+ channel gene families, such as the erg family (Meves et al., 1999; Selyanko et al., 1999). In the present experiments, we have used the acute expression of pore-defective mutants of KCNQ3 (DN-KCNQ3) and Merg1a (DN-Merg1a) as dominant negatives to separate the contributions of these two families to M-like currents in NG108-15 neuroblastoma hybrid cells and rat sympathetic neurons. Two kinetically and pharmacologically separable components of M-like current could be recorded from NG108-15 cells that were individually suppressed by DN-Merg1a and DN-KCNQ3, respectively. In contrast, only DN-KCNQ3, and not DN-Merg1a, reduced currents recorded from sympathetic neurons. Pharmacological tests suggested that the residual current in DN-KCNQ3-treated sympathetic neurons was carried by residual KCNQ channels. Ineffectiveness of DN-Merg1a in sympathetic neurons was not caused by lack of expression, as judged by confocal microscopy of Flag-tagged DN-Merg1a. These results accord with previous inferences regarding the roles of erg and KCNQ channels in generating M-like currents. This experimental approach should therefore be useful in delineating the contributions of members of these two gene families to K+ currents in other cells.

Dental caries-protective agents in milk and milk products: investigations in vitro

OBJECTIVES

To characterise and identify the anti-dental caries components that exist in milk and milk products.

METHODS

Standard enamel or hydroxyapatite demineralisation tests were devised to simulate the action of acid on tooth mineral, and they were used to show which constituents of milk possessed a potential protective action against acid attack.

RESULTS

Milk and milk products were fractionated and tested, revealing that minerals, including calcium and phosphorus, played a part in this protective process. The findings also drew attention to the effectiveness of minor milk protein or protein-associated components, the structures of which are mostly known, which were separated and characterised by gel electrophoresis as proteose-peptone fractions 3 and 5. The strength of adsorption of the protein or polypeptides in these fractions to dental enamel was measured and found to be sufficient to reduce the extent of demineralisation of enamel by acid buffer solutions.

CONCLUSIONS

The removal of lactose, fat, casein and other proteins had little influence on the protective effect of the milk fractions. Besides calcium and phosphorus, milk contains other more powerful protective factors, which were identified as proteose-peptone fractions 3 and 5. Details of their composition and the strength of their adherence to the surface of dental mineral are given.

Apolipoprotein J/clusterin limits the severity of murine autoimmune myocarditis

Apolipoprotein J/clusterin (apoJ/clusterin), an intriguing protein with unknown function, is induced in myocarditis and numerous other inflammatory injuries. To test its ability to modify myosin-induced autoimmune myocarditis, we generated apoJ-deficient mice. ApoJ-deficient and wild-type mice exhibited similar initial onset of myocarditis, as evidenced by the induction of two early markers of the T cell-mediated immune response, MHC-II and TNF receptor p55. Furthermore, autoantibodies against the primary antigen cardiac myosin were induced to the same extent. Although the same proportion of challenged animals exhibited some degree of inflammatory infiltrate, inflammation was more severe in apoJ-deficient animals. Inflammatory lesions were more diffuse and extensive in apoJ-deficient mice, particularly in females. In marked contrast to wild-type animals, the development of a strong generalized secondary response against cardiac antigens in apoJ-deficient mice was predictive of severe myocarditis. Wild-type mice with a strong Ab response to secondary antigens appeared to be protected from severe inflammation. After resolution of inflammation, apoJ-deficient, but not wild-type, mice exhibited cardiac function impairment and severe myocardial scarring. These results suggest that apoJ limits progression of autoimmune myocarditis and protects the heart from postinflammatory tissue destruction.

Properties of maltodextrins and glucose syrups in experiments in vitro and in the diets of laboratory animals, relating to dental health

The objective of the study was to examine the cariogenic potentials of maltodextrins and glucose syrups (two glucose polymers derived from starch) using a range of techniques in vitro and in laboratory animals. The experimental methods used were: (1) measurement of acid production from glucose syrups and maltodextrins by human dental plaque micro-organisms; (2) evaluation of the role salivary alpha-amylase in degrading oligosaccharides (degree of polymerisation > 3) in the glucose polymers, estimating the products by HPLC; (3) assessment of the fermentability of trioses relative to maltose; (4) measurement of dental caries levels in three large-scale studies in laboratory rats fed on diets containing the glucose polymers. It was found that acid production from the glucose polymers increased as their higher saccharide content fell. Salivary alpha-amylase rapidly degraded the oligosaccharides (degree of polymerisation > 3), mainly to maltose and maltotriose. In the presence of oral micro-organisms, maltotriose took longer to ferment than maltose, but by the end of a 2 h period the total amount of acid produced was the same from both. Incorporated into the diets in solid form, the glucose syrups and maltodextrins were associated with unexpectedly high levels of dental caries. In conclusion, the findings were unforeseen in the light of earlier data that a glucose syrup was less cariogenic than sucrose.

Transmission of IgA and IgG monoclonal antibodies to mucosal fluids following intranasal or parenteral delivery

BACKGROUND

The efficacy by which passive antibodies can reach the lungs could be important for the outcome of immunotherapy of respiratory pulmonary infections. We examined how transmission to a number of mucosal sites is affected by the route of inoculation.

METHODS

Transmission of newly raised IgA class Mabs against mycobacterial surface antigens to saliva, lung or vaginal lavage, bile and serum of BALB/c mice was compared with existing IgG Mabs. ELISA was used for testing body fluids obtained 1-24 h after intranasal or intravenous inoculation and 1-7 days following back-pack tumour growth of hybridomas.

RESULTS

Intranasal inoculation resulted in a rapid rise and high levels of both IgA and IgG class Mabs in lung lavage. In contrast, following intravenous Mab injection or back-pack tumour growth of hybridoma cells, effective lung transmission was observed for the IgG1 and IgG2b MAbs, but not for the IgA Mabs. The secretory component was acquired by the transmitted IgA MAbs in the mucosal fluids, but not in the serum. Nevertheless, the time course of mucosal IgA antibody levels was similar to that of the tested IgG Mabs. Furthermore, the relative proportion of transmission to saliva and bile varied between individual Mabs indicating a role of tissue-specific, immunoglobulin class-unrelated mechanisms.

CONCLUSIONS

Intranasal, rather than parenteral inoculation of mice is required for the efficient delivery of IgA antibodies against respiratory pulmonary pathogens. Interestingly, IgA-secretory component complexing of intranasally applied Mabs did not significantly influence their persistence in the lungs.

The effect of extended family living on the mental health of three generations within two Asian communities

BACKGROUND

A study by Shah & Sonuga-Barke (1995) identified a relationship between family structure and the mental health of Pakistani Muslim mothers and their children. Children in extended families fared better, but their mothers fared worse than their nuclear family counterparts. The present study replicates and extends this study by exploring the impact of nuclear and extended family living on the mental health of three generations (children, mothers and grandmothers) in British Hindu as well as Muslim communities.

METHOD

44 Muslim and 42 Hindu families participated in the study. The mental health of mothers and grandmothers and the behavioural problems of children (aged 5-11) were examined. Both mothers and grandmothers completed the Hospital Anxiety and Depression Scale. The children's behavioural adjustment was rated by their teachers using the Rutter Scale. Other relevant variables such as acculturation levels were also measured.

RESULTS

Children and grandmothers were better adjusted in extended families than nuclear families. In contrast, mothers were better adjusted in nuclear families. This interaction between family type and generation was evident in both Muslim and Hindu families and did not appear to be mediated by other variables such as acculturation. Furthermore, mothers' and childrens' adjustment was significantly correlated with grandmothers', but not mothers', mental health in extended families (although not in nuclear families).

DISCUSSION

These results provide further evidence for the link between family structure and mental health in Asian communities. They also challenge some of the assumptions about maternal mental health, its effects on child adjustment and its links to systems of social support. In extended families where social support was likely to be most available mothers were at greatest risk, while their children profited and this advantage seemed to be linked to the grandmaternal presence.

Repression and activation of muscarinic receptor genes

The specific cellular response to muscarinic receptor activation is dependent upon appropriate expression of each of the five muscarinic receptor genes by individual cells. Here we summarise recent work describing some of the genomic regulatory elements and transcriptional mechanisms that control expression of the M1 and M4 genes.

The mental health of Muslim mothers in extended families living in Britain: the impact of intergenerational disagreement on anxiety and depression

OBJECTIVES

The study assessed the impact of intergenerational differences of opinion over child rearing on the mental health of Muslim mothers living in extended families.

DESIGN

The study adopted a correlational design in an attempt to identify factors that accounted for mental health problems.

METHODS

The child-rearing attitudes of mothers and grandmothers, mothers' mental health, levels of family acculturation and a range of other background and demographic information was collected from 54 extended families living in two Muslim communities in London using Urdu versions of standard questionnaires.

RESULTS

Rates of depression and anxiety among the mothers in the study were high. Grandmothers had more traditional attitudes to child rearing than did mothers. Intergenerational discrepancy over child rearing was more marked in more acculturated families. Discrepancy was associated with higher levels of mothers' anxiety and depression.

CONCLUSIONS

The unusually high levels of depression and anxiety displayed by Muslim mothers living in extended families can in part be accounted for by patterns of intergenerational discrepancy. These possibly reflect discordant world views within those families that have been assimilated into the dominant British culture.

Beneficial action of beraprost sodium, a prostacyclin analog, in stroke-prone rats

Beraprost sodium is a stable analog of the vasodilator, platelet antiaggregatory eicosanoid, prostacyclin. Experiments were performed to determine whether long-term therapy with beraprost produces vascular protective effects in saline-drinking stroke-prone spontaneously hypertensive rats (SHRSPs). Oral beraprost at 30, 100, or 300 micrograms/kg/day starting at 8.4 weeks of age did not affect the progressive increase of systolic blood pressure (measured by tail-cuff plethysmography) in these rats. Additional experiments in SHRSPs, prepared for continuous monitoring of blood pressure by radiotelemetry, revealed that oral beraprost administration reduced mean arterial pressure but that these hypotensive responses were not sustained (< 4 h). In all SHRSPs receiving oral beraprost, proteinuria and cerebrovascular lesions developed. In contrast, continuous subcutaneous infusion of beraprost at 2.8 mg/kg/day from age 8.3-12.3 weeks reduced systolic blood pressure and markedly diminished the development of renal lesions and the occurrence of stroke in saline-drinking SHRSPs. Beraprost at 0.9 mg/kg/day reduced blood pressure less than did 2.8 mg/kg/day and provided partial protection against cerebral and renal lesions after a 4-week infusion period. These results indicate that long-term subcutaneous infusion of beraprost can protect saline-drinking SHRSPs against stroke and renal damage. This effect is not readily dissociated from the ability of beraprost to reduce blood pressure in SHRSPs.

Laboratory studies of sweets re-formulated to improve their dental properties

OBJECTIVES

To evaluate the potential dental effects of ten new types of sugar-free sweets formulated with Lycasin or isomalt as bulk sweeteners instead of sugars.

METHODS

Examination of the sweets for their acidity, fermentability by oral microorganisms, influence on the demineralisation of dental enamel, and their influence on human interdental plaque pH, compared with conventional sugar-containing sweets.

FINDINGS

The importance of reducing the levels of flavouring acids in the sweets was demonstrated. It was not straightforward to evaluate chocolate products in this system, but the potential benefits of re-formulating fruit gums, lollipops, chew-bars, toffee and fudge with Lycasin or isomalt in place of sugars were shown by determining their reduced acidogenicity and fermentability compared with conventional confectionery.

CONCLUSIONS

The extent of demineralisation of dental enamel was related to both the acidity and the fermentability of the sweets. Re-formulating sweets with reduced acidity levels and bulk sweeteners not fermentable by dental plaque microorganisms can provide a basis for improving their potential dental effects.

Precise control of the frequency and amount of food provided for small laboratory animals by a new electronic metering technique, used to evaluate the cariogenic potential of chocolate

A new electronic system was set up for accurately regulating the amount and frequency of food dispensed to laboratory rats so that investigations of the cariogenic potential of foods can be carried out under strictly controlled conditions according to the stipulations of the San Antonio Consensus Conference, 1985. The system was used to evaluate the cariogenicity of sucrose incorporated into plain and milk chocolate. The results suggested that 18.75% of sucrose in the diet had the same cariogenic potential no matter whether it was in the form of fine crystals or incorporated into plain chocolate, but mean caries scores were nearly 30% higher on a plain chocolate than on a milk chocolate regime.