Dietary habits of lesser bandicoot rat (Bandicota Bengalensis) in an agro-ecosystem, Pothwar Plateau, Pakistan / Hábitos alimentares de rato bandicoot (Bandicota Bengalensis) em um agroecossistema do Planalto de Pothwar, Paquistão

Abstract Dietary habits of bandicoot rats (bandicota bengalensis) were investigated in the agricultural crops of the Pothwar Plateau, Pakistan by analysing stomach contents. The research activities were conducted in major field crops including wheat-groundnut and in the fallow lands during non-crop season at the field boundaries. The specimens were captured from the fields using kill/snap traps, and dissected to collect their stomach samples for laboratory analysis. Light microscopic slides of the plant material were recovered from stomach samples and the reference materials were collected from the field. Results revealed that the bandicoot rat predominantly fed upon cultivated crops during cropping season but consumed wild vegetation during non-cropping season. There was no significance difference between summer and winter diets. Most frequently consumed crop food items were wheat (Triticum aestivum; 28.57%), groundnut (Arachis hypogea; 11.26%), sorghum (Sorghum bicolor; 10.17%), chickpea (Cicer arietinum; 9.52%), maize (Zea mays; 6.49%), millet (Pennisetum glaucum; 5.84%), barley (Hordeum vulgare; 4.98%) and mustard (Brassica campestris; 4.98%). Among wild vegetation were consumed khbal gha (Cynodon dactylon; 7.79%), baron dhab (Demostachya bipinnata; 7.36%) and Prickly flower (Achyranthes aspera; 3.03%). The study concludes that, in addition to consuming wheat and groundnut crops, the Lesser bandicoot rat also subsists on grasses, weeds, and some fodder crops, as important component of its diet in agro-ecosystem of the Pothwar Plateau.

Resumo Os hábitos alimentares de ratos bandicoot (Bandicota bengalensis) foram investigados nas plantações agrícolas do planalto de Pothwar, Paquistão, por meio da análise do conteúdo estomacal. As atividades da pesquisa foram conduzidas nas principais culturas de campo, incluindo trigo e amendoim, e em terras de pousio durante a estação não agrícola nos limites do campo. Os espécimes foram capturados dos campos usando armadilhas kill/snap e dissecados para coletar suas amostras de estômago para análise laboratorial. Lâminas de microscopia de luz do material vegetal foram recuperadas de amostras de estômago; os materiais de referência foram coletados no campo. Os resultados revelaram que o rato bandicoot alimentava-se predominantemente de culturas cultivadas durante a época de cultivo, mas consumia vegetação selvagem durante a época de não colheita. Não houve diferença significativa entre as dietas de verão e inverno. Os alimentos agrícolas mais frequentemente consumidos foram trigo (Triticum aestivum; 28,57%), amendoim (Arachis hypogea; 11,26%), sorgo (Sorghum bicolor; 10,17%), grão de bico (Cicer arietinum; 9,52%), milho (Zea mays; 6,49%), milheto (Pennisetum glaucum; 5,84%), cevada (Hordeum vulgare; 4,98%) e mostarda (Brassica campestris; 4,98%). Entre a vegetação silvestre foram consumidos khbal gha (Cynodon dactylon; 7,79%), barão dhab (Demostachya bipinnata; 7,36%) e flor espinhosa (Achyranthes aspera; 3,03%). O estudo conclui que, além de consumir culturas de trigo e amendoim, o rato bandicoot pequeno também subsiste de gramíneas, ervas daninhas e algumas culturas forrageiras, componentes importantes de sua dieta no agroecossistema do planalto de Pothwar.

Dietary habits of lesser bandicoot rat (Bandicota Bengalensis) in an agro-ecosystem, Pothwar Plateau, Pakistan

Abstract Dietary habits of bandicoot rats (bandicota bengalensis) were investigated in the agricultural crops of the Pothwar Plateau, Pakistan by analysing stomach contents. The research activities were conducted in major field crops including wheat-groundnut and in the fallow lands during non-crop season at the field boundaries. The specimens were captured from the fields using kill/snap traps, and dissected to collect their stomach samples for laboratory analysis. Light microscopic slides of the plant material were recovered from stomach samples and the reference materials were collected from the field. Results revealed that the bandicoot rat predominantly fed upon cultivated crops during cropping season but consumed wild vegetation during non-cropping season. There was no significance difference between summer and winter diets. Most frequently consumed crop food items were wheat (Triticum aestivum; 28.57%), groundnut (Arachis hypogea; 11.26%), sorghum (Sorghum bicolor; 10.17%), chickpea (Cicer arietinum; 9.52%), maize (Zea mays; 6.49%), millet (Pennisetum glaucum; 5.84%), barley (Hordeum vulgare; 4.98%) and mustard (Brassica campestris; 4.98%). Among wild vegetation were consumed khbal gha (Cynodon dactylon; 7.79%), baron dhab (Demostachya bipinnata; 7.36%) and Prickly flower (Achyranthes aspera; 3.03%). The study concludes that, in addition to consuming wheat and groundnut crops, the Lesser bandicoot rat also subsists on grasses, weeds, and some fodder crops, as important component of its diet in agro-ecosystem of the Pothwar Plateau.

Resumo Os hábitos alimentares de ratos bandicoot (Bandicota bengalensis) foram investigados nas plantações agrícolas do planalto de Pothwar, Paquistão, por meio da análise do conteúdo estomacal. As atividades da pesquisa foram conduzidas nas principais culturas de campo, incluindo trigo e amendoim, e em terras de pousio durante a estação não agrícola nos limites do campo. Os espécimes foram capturados dos campos usando armadilhas kill/snap e dissecados para coletar suas amostras de estômago para análise laboratorial. Lâminas de microscopia de luz do material vegetal foram recuperadas de amostras de estômago; os materiais de referência foram coletados no campo. Os resultados revelaram que o rato bandicoot alimentava-se predominantemente de culturas cultivadas durante a época de cultivo, mas consumia vegetação selvagem durante a época de não colheita. Não houve diferença significativa entre as dietas de verão e inverno. Os alimentos agrícolas mais frequentemente consumidos foram trigo (Triticum aestivum; 28,57%), amendoim (Arachis hypogea; 11,26%), sorgo (Sorghum bicolor; 10,17%), grão de bico (Cicer arietinum; 9,52%), milho (Zea mays; 6,49%), milheto (Pennisetum glaucum; 5,84%), cevada (Hordeum vulgare; 4,98%) e mostarda (Brassica campestris; 4,98%). Entre a vegetação silvestre foram consumidos khbal gha (Cynodon dactylon; 7,79%), barão dhab (Demostachya bipinnata; 7,36%) e flor espinhosa (Achyranthes aspera; 3,03%). O estudo conclui que, além de consumir culturas de trigo e amendoim, o rato bandicoot pequeno também subsiste de gramíneas, ervas daninhas e algumas culturas forrageiras, componentes importantes de sua dieta no agroecossistema do planalto de Pothwar.

Controlled Ovarian Stimulation Initiated at Different Phases of the Menstrual Cycle for Fertility Preservation in Oncological Patients: a Retrospective Study.

The purpose of this study is to compare conventional start in early follicular phase (EFP) with late follicular phase (LFP) and luteal phase (LP) in controlled ovarian stimulation (COS) for fertility preservation (FP) to assess differences in clinical outcomes. Retrospective study of the first cycles of COS for FP in oncological patients between 2012 and 2020 in a tertiary hospital. Two-hundred forty-eight cycles were classified into 3 groups: 176 cycles in EFP, 8 cycles in LFP, and 52 cycles in LP. Comparing LFP to EFP, there were no differences in number of oocytes (10.0 [6.3-16.0] vs 12.0 [8.0-18.0]; p = 0.253) or number of metaphase II (MII) obtained (7.0 [2.3-13.3] vs 9.0 [6.0-13.0]; p = 0.229). Total number of days needed was higher in LFP (14.5 [12.5-16.0] vs 3.0 vs 10.0 [8.3-11.0 p = 0.000) but without significant differences in number of days of usage of gonadotropins (11.5 [8.3-12.8] vs 10.0 [8.3-11.0] p = 0.308). No differences were found between LP and EFP in number of oocytes (14.5 [9.0-20.0] p = 0.151) or MII (11.5 [7.0-16.0] p = 0.084). Number of days of gonadotropins (11.0 [10.0-12.0] p = 0.00) and total dosing (3000.0 [2475.0-3600.0] p = 0.013) were significantly higher in LP. FORT and FOI were similar in all groups. COS with a random start in fertility preservation has similar outcomes to EFP start. Therefore, we can initiate COS at any phase of the menstrual cycle with optimal results. However, LP may need more days of stimulation.

Small rodent communities and their associated damage to wheat-groundnut agriculture systems.

Rodents can cause significant damage to wheat-groundnut crops in developing countries, as well as to stored produce and infrastructure, affecting food security and income of small-holder farmers. Wheat (Triticum aestivum) and groundnuts (Arachis hypogea) are important cash crops for local farmers in Pakistan. Field experiments were performed to assess the extent of rodent damage to wheat-groundnut crops throughout their growth stages (i.e, germination, flowering/peg formation and maturity) in the agro-ecological zones of Pothwar Plateau, Pakistan. We used a quadrat method to record the number of damaged crop plants. On the basis of the trapping data four rodent species were captured from wheat-groundnut cropping systems which were responsible for causing damage, i.e., lesser bandicoot rat (Bandicota bengalensis) was the main species, followed by the short-tailed mole rat (Nesokia indica), the Indian gerbil (Tatera indica) and the bush rat (Golunda ellioti). In both crops, the maximum damage was recorded at crop maturity (10.7 and 14.4%, respectively). The lowest reported damage to wheat and groundnuts was at the germination stage (3.5% and 6.0%, respectively). The lower damage reported at germination could be due to availability of non-crop vegetation at field borders that may be a potential factor influencing damage. Our findings clearly show the considerable amount of damage caused by rodents to wheat-groundnut at maturity across all the agro-ecological zones of Pothwar and indicated that the small mammal composition was more related to maturity stage/season of crops, when the availability of food and climatic condition were favorable and having security under crop shelter. More detailed studies are needed to fully understand the population and breeding ecology of the relevant rodent pest species in relation to damage patterns to optimize management beyond individual structural measures.

Dietary habits of lesser bandicoot rat (Bandicota Bengalensis) in an agro-ecosystem, Pothwar Plateau, Pakistan.

Dietary habits of bandicoot rats (bandicota bengalensis) were investigated in the agricultural crops of the Pothwar Plateau, Pakistan by analysing stomach contents. The research activities were conducted in major field crops including wheat-groundnut and in the fallow lands during non-crop season at the field boundaries. The specimens were captured from the fields using kill/snap traps, and dissected to collect their stomach samples for laboratory analysis. Light microscopic slides of the plant material were recovered from stomach samples and the reference materials were collected from the field. Results revealed that the bandicoot rat predominantly fed upon cultivated crops during cropping season but consumed wild vegetation during non-cropping season. There was no significance difference between summer and winter diets. Most frequently consumed crop food items were wheat (Triticum aestivum; 28.57%), groundnut (Arachis hypogea; 11.26%), sorghum (Sorghum bicolor; 10.17%), chickpea (Cicer arietinum; 9.52%), maize (Zea mays; 6.49%), millet (Pennisetum glaucum; 5.84%), barley (Hordeum vulgare; 4.98%) and mustard (Brassica campestris; 4.98%). Among wild vegetation were consumed khbal gha (Cynodon dactylon; 7.79%), baron dhab (Demostachya bipinnata; 7.36%) and Prickly flower (Achyranthes aspera; 3.03%). The study concludes that, in addition to consuming wheat and groundnut crops, the Lesser bandicoot rat also subsists on grasses, weeds, and some fodder crops, as important component of its diet in agro-ecosystem of the Pothwar Plateau.

Development and validation of a new vision screening test algorithm for public use mobile application- A pilot study.

OBJECTIVES: To design and develop a simple vision test algorithm for mobile application and perform a pilot study to determine its validity and reliability as a tool for vision test in the community. METHODS: A simple visual acuity test algorithm in the form of a single letter E display was designed as the optotype for development of a mobile application. The standardised optotype is presented at random to test visual acuity for corresponding level of 3/60, 6/60, 6/18, and 6/12. The final result is auto-generated based on the classification of the WHO for visual impairment and blindness. The Snellen chart was used as the gold standard to determine its validity while five different users were involved to determine its inter-rater reliability. A pilot study was performed between April till November 2019, in the Universiti Sultan Zainal Abidin Medical Centre (UMC) at Kuala Nerus and Mooris Optometrist Centre at Marang, Terengganu. A total of 279 participants aged four years old and above were involved in this study. RESULTS: The highest sensitivity was found at the vision level cut-off point of 6/12 with the percentage of 92.7% and 86.8% for the right and left eye, respectively. The specificity was more than 89% for all vision levels in both eyes. The Krippendorff's alpha value for the inter-rater reliability was 0.87 and 0.83. CONCLUSION: The relatively high level of validity and reliability obtained indicate the feasibility of using the designed optotype to develop a valid and reliable mobile app for vision test. The app can be used to screen vision by nonmedical persons, at anytime and anywhere to help improve public awareness and capability to correctly determine their visual status.

Invasive Pleomorphic-Type Lobular Carcinoma of the Breast Presenting as a Mucinous Carcinoma.

Invasive mucinous carcinoma of the breast is mostly associated with invasive carcinoma of no special type (NST) and sometimes with neuroendocrine type tumors such as solid papillary carcinoma. Extracellular mucin production in invasive lobular carcinoma (ILC) is extremely rare. To the best of our knowledge only 18 such cases have been described in the literature. Here we present a unique case of invasive pleomorphic-type lobular carcinoma (IPTLC) presenting as a mucinous carcinoma of the breast on core needle biopsy. Here we discuss the impact and ways to suspect such case.

Progression pattern and adverse events with bevacizumab in glioblastoma.

BACKGROUND: The use of bevacizumab in the management of glioblastoma multiforme (gbm) remains controversial. In Canada, bevacizumab is approved for the treatment of recurrent gbm. We describe a pattern of progression across treatment lines in gbm. METHODS: During 2008-2014, 64 patients diagnosed with gbm were treated with bevacizumab at McGill University hospitals. Of those patients, 30 (46.9%) received bevacizumab in the first line (B1L), and 34 (53.1%) received it in the second line and beyond (B2L+). The average length of treatment with bevacizumab was 24.4 weeks (range: 0-232.7 weeks). The patterns of progression were categorized as local, distant, diffuse, multifocal, or multi-pattern. RESULTS: Local progression was seen in 46.7% of B1L patients and 26.5% of B2L+ patients, distant in 3.3% and 2.9%, diffuse in 20% and 47%, multifocal in 10% and 8.8%, and multi-pattern in 3.3% and 11.8%. No differences between the groups were observed for the distant (p = 0.3) or diffuse (p = 0.4) patterns. Grades 3 and 4 adverse events in the B1L and B2L+ groups were fatigue (33.3% vs. 17.6% respectively), hypertension (26.7% vs. 5.9%), thrombocytopenia (26.7% vs. 11.8%), neutropenia (26.7% vs. 11.8%), anemia (23.3% vs. 11.8%), leucopenia (20% vs. 8.8%), deep vein thrombosis (23.3% vs. 5.9%), seizure (16.7% vs. 8.8%), brain hemorrhage (6.7% vs. <1%), and delayed wound healing (6.7% vs. 2.9%). More total grades 3 and 4 adverse events occurred in the B1L group (p = 0.000519). CONCLUSIONS: In our cohort, patterns of progression were not different in B1L and B2L+ patients. Moreover, both groups experienced similar adverse events, although more grades 3 and 4 events occurred in the B1L group, implying that severe adverse events in B1L patients could negatively affect survival outcomes.

Retrospective analysis of the effect of CAPOX and mFOLFOX6 dose intensity on survival in colorectal patients in the adjuvant setting.

BACKGROUND: Despite lack of a true comparative study, the folfox (5-fluorouracil-leucovorin-oxaliplatin) and capox (capecitabine-oxaliplatin) regimens are believed to be similar in their efficacy and tolerability in the treatment of stage iii colorectal cancer. However, that belief has been disputed, because real-life data suggest that the capox regimen is more toxic, leading to more frequent reductions in the delivered dose intensity-thus raising questions about the effect of dose intensity on clinical outcomes. METHODS: A retrospective data review for two Canadian institutions, the Segal Cancer Centre and the Tom Baker Cancer Centre, considered patients diagnosed with stage iii colorectal cancer during 2006-2013. Primary endpoints were dose intensity and toxicity, with a secondary endpoint of disease-free survival. RESULTS: The study enrolled 180 eligible patients (80 at the Segal Cancer Centre, 100 at the Tom Baker Cancer Centre). Of those 180 patients, 75 received capox, and 105 received mfolfox6. In the capox group, a significant dose reduction was identified for capecitabine compared with 5-fluorouracil in mfolfox6 group (p = 0.0014). Similarly, a significant dose reduction was observed for oxaliplatin in mfolfox6 compared with oxaliplatin in capox (p = 0.0001). Compared with the patients receiving capox, those receiving mfolfox6 were twice as likely to experience a treatment delay of more than 1 cycle-length (p = 0.03855). Toxicity was more frequent in patients receiving mfolfox6 (nausea: 30% vs. 18%; diarrhea: 47% vs. 24%; peripheral sensory neuropathy: 32% vs. 3%). At a median follow-up of 40 months, preliminary data showed no difference in disease-free survival (p = 0.598). Pooled data from both institutions were also separately analyzed, and no significant differences were found. CONCLUSIONS: Our results support the use of capox despite a lack of head-to-head randomized trial data.

Quantifying treatment delays in adolescents and young adults with cancer at McGill University.

BACKGROUND: Since the end of the 1980s, the magnitude of survival prolongation or mortality reduction has not been the same for adolescents and young adults (ayas) with cancer as for their older and younger counterparts. Precise reasons for those observations are unknown, but the differences have been attributed in part to delays in diagnosis and treatment. In 2003 at the Jewish General Hospital, we developed the first Canadian multidisciplinary aya oncology clinic to better serve this unique patient population. The aim of the present study was to develop an approach to quantify diagnosis delays in our aya patients and to study survival in relation to the observed delay. METHODS: In a retrospective chart review, we collected information about delays, treatment efficacy, and obstacles to treatment for patients seen at our aya clinic. RESULTS: From symptom onset, median time to first health care contact was longer for girls and young women (62 days) than for boys and young men (6 days). Median time from symptom onset to treatment was 173 days; time from first health care contact to diagnosis was the largest contributor to that duration. Delays in diagnosis were shorter for patients who initially presented to the emergency room, but compared with patients whose first health contact was of another type, patients presenting to the emergency room were 3 times more likely to die from their disease. CONCLUSIONS: Delays in diagnosis are frequently reported in ayas with cancer, but the duration of the delay was unrelated to survival in our sample. Application of this approach to larger prospective samples is warranted to better understand the relation between treatment delay and survival in ayas-and in other cancer patient groups.

The association between indices of obesity and common clinical measures in adults with and without type 2 diabetes

OBJECTIVE: To determine if there are any differences in anthropometric measurements, lipid profile, blood pressure and body shape between diabetics and non-diabetics. DESIGN AND METHODS: This cross-sectional study comprised 309 subjects with 91 males and 218 females; there were 217 diabetics and 92 non-diabetics. The sample was taken from three hospitals in Trinidad. Lipid profile and blood pressure were taken from each facility’s physicians’ notes while anthropometric measurements were taken from the patients themselves. RESULTS: The diabetic group had elevated body mass index, and waist to hip ratios were significantly higher (p<0.05) when compared to non-diabetics. There was no significant difference in lipid profile and blood pressure between diabetics and non-diabetics. As age increased, the prevalence of type 2 diabetes mellitus was higher. Of the 217 diabetics, 173 were of East Indian descent. With regards to gender, more males were found to be diabetics resulting from having an android body shape as compared to females (gynoid body shape). It was deduced that waist to hip ratio was the best indicator of type 2 diabetes mellitus based on the area under the curve analysis. CONCLUSION: Of all the anthropometric measurements used, waist to hip ratio was found to be the most effective indicator of type 2 diabetes mellitus in Trinidadians, while body mass index was found to be the least.

Reversible brainstem dysfunction from spinal arterio-venous fistula.

A 45-year-old man presented with subacute onset of ataxia, diplopia, urinary retention and paraparesis. MR scan of brain showed abnormal T2 hyperintense signal within the cervical cord, medulla and lower pons and vascular appearances suggesting an arterio-venous fistula. The fistula was surgically explored and successfully disconnected with good clinical outcome. Brainstem or cervical dural arterio-venous fistulae more typically present as a myelopathy; only a handful of cases have presented with brainstem dysfunction. This is a rare but reversible cause of subacute brainstem dysfunction.

Unreported location and presentation for a parasitic ovarian dermoid cyst in an indirect inguinal hernia.

Extragonadal mature cystic teratomas (dermoid cysts) have been reported occasionally, with the most common site being the omentum. We report a rare case of a parasitic dermoid cyst that was incidentally found in an indirect inguinal hernia sac in a 66-year-old woman. The right ovary was absent from its proper anatomical location. Histopathologic study revealed a mature cystic teratoma with viable ovarian tissue. These findings suggested auto-amputation of the ovary either by inflammation or torsion.

Epidemiological trends of leprosy elimination in CLTRI rural field operation area, Tamil Nadu, India.

The analysis of computerized data of patients in our Rural Field Operation Area (Kunrathur Taluk, Kancheepuram District, Tamil Nadu) from the start of MDT in 1986 has shown a decrease of leprosy prevalence from 275/10000 in 1986 to 0.7/10000 in 2005. Leprosy has been eliminated as a public health problem after 19 years of MDT implementation. Although the control programme was started in 1962, MDT implementation began only in 1986. The new case-detection rate has declined significantly from 27.3 in 1987 to 2.4/10000 in 2005 (y = -1.6x + 2325.1, p = < 0.05). The age-specific cumulative detection rates calculated showed highest case-detection at 10-14 years for total, 10-14 years for PB, 50-54 for MB, and 10-14 for both males and females. MB percentage was more among new cases in the last three years as compared to the initial three years, and this difference was found to be statistically significant, but there was no significant difference between the first three and the last three-year periods in child, male and disability rates (grade +/-2) among new cases. Thus, the declining trend in NCDR has not reflected any change in sex and age-groups of new cases. This analysis strengthens the hypothesis of sub-clinical cases possibly transmitting the disease and MB cases accruing after long incubation period.

A comparative study of the metastable equilibrium solubility behavior of high-crystallinity and low-crystallinity carbonated apatites using pH and solution strontium as independent variables.

UNLABELLED: Using solution strontium and pH as independent variables, the metastable equilibrium solubility (MES) behavior of two carbonated apatite (CAP) samples has been examined, a high-crystallinity CAP (properties expected to be similar to dental enamel) and a low-crystallinity CAP (properties expected to be similar to bone mineral). CAP samples were prepared by precipitation/digestion: (CAP A: high-crystallinity, 1.3 wt% CO3, synthesized at 85 degrees C; CAP B: low-crystallinity, 6.4 wt% CO3, synthesized at 50 degrees C). Baseline MES distributions were determined in a series of 0.1 M acetate buffers containing only calcium and phosphate (no strontium) over a broad range of solution conditions. To assess the influence of strontium, MES profiles were determined in a similar fashion with 20, 40, 60, and 80% of the solution calcium being replaced on an equal molar basis by solution strontium. To determine the correct function governing CAP dissolution, ion activity products (IAPs) were calculated from the compositions of buffer solutions based on the hydroxyapatite template (Ca(10-n)Sr(n)(PO4)6(OH)2 (n = 0-10)) and the calcium/hydroxide deficient hydroxyapatite template (Ca(9-n)Sr(n)(HPO4)(PO4)5OH (n = 0-9)). FINDINGS: (a) for CAP A, at high solution strontium/calcium ratios, the MES profiles were essentially superimposable when the solution IAPs were calculated using the stoichiometry of Ca6Sr4(PO4)6(OH)2 and for CAP B by a stoichiometry of Ca7Sr2(HPO4)(PO4)5OH; (b) for CAP A, at low strontium/calcium ratios, the stoichiometry yielding MES data superpositioning was found to be that of hydroxyapatite and for CAP B, that of calcium/hydroxide deficient hydroxyapatite. When other stoichiometries were assumed, good superpositioning of the data was not possible.

Metastable equilibrium solubility behavior of carbonated apatite in the presence of solution strontium.

The purpose of this study was to use the concept of metastable equilibrium solubility (MES) to describe the anomalous solubility behavior of carbonated apatite (CAP) in the presence of solution strontium. A CAP sample (4.8 wt% CO(3), synthesized at 70 degrees C) was prepared by precipitation. Baseline MES distributions were determined in a series of 0.1 M acetate buffers containing only calcium and phosphate (no strontium) over a broad range of solution conditions. In order to assess the influence of strontium, MES profiles were then determined in a similar fashion with 20, 30, 40, 50, 60, 70, and 80% of the solution calcium being replaced on an equal molar basis by solution strontium. From the compositions of the equilibrating buffer solutions, ion activity products (IAPs) of the form Ca(10-n)Sr(n)(PO(4))(6)(OH)(2) (n = 0-10) were calculated in an attempt to determine the correct function governing the dissolution of the CAP preparation. The results demonstrate the following important findings: (a) at high solution strontium/calcium ratios (i.e., when 60% or more of the solution calcium was replaced by strontium), the MES profiles in all the experiments were found to be essentially superimposable when the solution IAPs were calculated using the stoichiometry of Ca(6)Sr(4)(PO(4))(6)(OH)(2), and (b), at low solution strontium/calcium ratios (i.e., when 40% or less of the solution calcium was replaced by strontium), the stoichiometry yielding MES data superpositioning was found to be that of hydroxyapatite. When other stoichiometries were assumed, good superpositioning of the data was not possible.

Effect of fluoride pretreatment on the solubility of synthetic carbonated apatite.

The purpose of this research was to address the following question: How is the solubility of fluoride-pretreated carbonated apatite (CAP) in aqueous acidic media related to the equilibrium solution fluoride and/or the CAP adsorbed fluoride levels? A CAP sample prepared by a precipitation method at 70 degrees C containing approximately 6% carbonate was fluoride-treated (F adsorption from neutral aqueous solutions) to yield a approximately 1000 ppm F CAP and a approximately 3300 ppm F CAP. Metastable equilibrium solubility distributions were determined in acetate buffers at pH 5.0. Solution fluoride, calcium, phosphate, and pH were determined from the equilibrated solutions. The equilibrium solution fluoride levels were extremely low, e.g., as low as approximately 0.10 ppb to approximately 0.30 ppb at 50% dissolved for the two CAP preparations. The approximately 3300 ppm F CAP yielded a lower solubility than the approximately 1000 ppm F CAP (shift in the mean pKHAP value of 1.5-2 units). This can be attributed to the lower solution F(-) for the sample containing approximately 1000 ppm fluoride compared with the approximately 3300 ppm fluoride-containing CAP. These important findings suggest that a fluoride treatment simply may provide an adsorption fluoride depot for subsequent release, providing a solution fluoride effect upon the CAP solubility and not necessarily any intrinsic alteration of the mineral solubility.

Effect of age on rat bone solubility and crystallinity.

It has been shown that biominerals such as dental enamel and bone demonstrate a non-thermodynamic equilibrium state following initial dissolution where no further mineral dissolution or precipitation occurs; this state is termed metastable equilibrium solubility (MES). Furthermore, these minerals are composed of a distribution of domains each with their own MES. Recent studies have also demonstrated a linear relationship between crystallinity and the mean MES of these minerals, with solubility decreasing with increasing crystallinity. This study investigates the effect of age on the MES and crystallinity of rat bone mineral. The bone mineral samples were prepared by protein extraction with a series of hydrazine and alcohol solutions. The MES distributions of the bone mineral were measured by exposure to 0.1 M acetate buffers containing a range of calculated amounts of calcium (Ca) and phosphate for 48 h. The amount of mineral dissolved in each solution was determined from Ca and phosphate analyses of the undissolved residue. The full width of the half maximum (FWHM) of the 002 reflection of the X-ray powder diffraction was used as an indicator of crystallinity. The MES of mineral from bone of rats of different ages (1-25 months) were compared. Results of this study indicate that (l) there is a difference in the mean MES of bone mineral from rats of different ages, with older bone mineral being less soluble and more crystalline than bone mineral from younger rats; (2) the nature of the solubility distribution changes from a narrow to a broader distribution with age; and (3) all of the bone samples demonstrated an inverse-linear correlation between crystallinity and mean MES value consistent with previous results obtained with synthetic apatites and dental enamel.

Influence of dentifrices and dietary components in saliva on wettability of pellicle-coated enamel in vitro and in vivo.

In vitro salivary pellicles were found to be less hydrophobic by water contact angles than clinically formed pellicles. In this study, water contact angles were measured on enamel coated with pellicles adsorbed from reconstituted human whole saliva (RHWS) and after exposure to dentifrices or dietary components. In addition, adhesion of Streptococcus oralis J22 to pellicles formed from RHWS with minor amounts of milk added and after exposure to dentifrices was studied. Exposure of RHWS-pellicles to milk or salad oil yielded an increase in the hydrophobicity of in vitro pellicles to values observed in vivo, but a decrease was seen after exposure to a sugar solution. Pellicles formed from saliva with 0.4% milk added attracted less S. oralis cells than pellicles formed in the absence of milk components. Exposure of pellicles formed from saliva with milk added to various dentifrices had a variable effect on bacterial adhesion: markedly lower numbers of adhering S. oralis were found for a dentifrice with NaF, but exposure to dentifrices containing SnF2 or hexametaphosphate showed slightly increased adhesion. In summary, dietary components have influence on the hydrophobicity of enamel pellicles, while combinations of dietary components and dentifrices certainly influence the adhesiveness of the pellicles. The effects of dietary components on pellicle conditioning film should be taken into consideration in research on the development of ingredients to control intraoral surface chemistry and microbiology, as well as in the development of oral products.