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Aim: Pelvic exenteration surgery remains the only curative option for recurrent rectal cancer. Microscopically involved surgical margins (R1) are associated with a higher risk of local recurrence and decreased survival. Our study aimed to develop a post hoc multidisciplinary case conference review and investigate its potential for identifying areas for improvement. Method: Patients who underwent pelvic exenteration surgery for recurrent rectal cancer with R1 resections at a tertiary referral centre between April 2014 and January 2016 were retrospectively reviewed from a prospectively maintained database. Patients with non‐rectal cancers or who underwent palliative surgery were excluded. Cases, imaging and histopathology were evaluated by a dedicated panel including colorectal surgeons, an abdominal radiologist and a gastrointestinal pathologist. Results: R1 resections were reported in 32 of 110 pelvic exenterations. Patients with other tumours were excluded and one patient had a palliative resection. Nine male patients with 11 exenterations were included with a median age of 56 years. All patients had positive soft tissue margins, and one patient also had an involved bony margin. Failures were due to (interdisciplinary) communication problems, specific management of tumour biology (multifocality, spiculated tumours), which can lead to radiological undercalling, and inadequate surgical technical planning. In hindsight, surgery would have been withheld from one patient. Conclusion: A retrospective multidisciplinary case evaluation of pelvic exenteration patients with involved surgical margins led to a list of recommendations which included the need to plan for wider surgical soft tissue resections and improvement in interdisciplinary communication. Lessons learned may increase clear margin rates in future resections. [ABSTRACT FROM AUTHOR]

Context. The Tasmanian Government is attempting to eradicate foxes from Tasmania and carnivore-scat surveys using humans and dogs combined with DNA testing are the main methods of detection. Understanding the rate that scats degrade is a key component for estimating the power of monitoring for detecting cryptic predators and will contribute to a broader understanding of the use of scat monitoring for informing eradication programs. Aims. To estimate the degradation rate of fox scats and derive an estimate of the abundance of scats available to observers monitoring for fox presence. Methods. In total, 486 fresh fox scats were placed at nine sites within three bioregions in Tasmania and left to degrade for up to 126 days. Scats were observed periodically by both humans and dogs to determine when they became unrecognisable and/or undetectable. Key results. Recognition of scats by humans declined faster in summer than in winter and did not vary systematically among bioregions. Median survival times of scats were 19 days in summer and 26 days in winter. Recognition of scats by dogs was higher in summer than in winter, with dogs recognising scats past the time they became unrecognisable to humans. Using estimates of scat degradation derived from human observers, the equilibrium abundance of detectable scats within a fox home range was estimated to be 179-243 scats. However, the abundance of detectable scats on linear features subject to monitoring was estimated to be 10-15 scats. Conclusions. Using our estimate of the abundance of scats on linear features, the current distribution of fox scats detected in Tasmania may not be as anomalous as has been suggested by others. However, fox detection from scats will be highly dependent on deposition patterns and distribution of scats on linear features and this should be critically reassessed in Tasmania. Implications. Fox scats are not expected to exhibit systematic regional differences in degradation rates that might have an impact on monitoring strategies. Estimates of the abundance of scats detectable by observers are critical for assessing the effectiveness of scat-monitoring programs. We advocate that a rigorous assessment of future scat-monitoring programs in Tasmania be undertaken to determine their power to detect foxes. [ABSTRACT FROM AUTHOR]

Effects of glucose infusion on feed intake, milk production, and metabolic responses of early postpartum cows fed diets varying in starch and protein concentration were evaluated by utilizing a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Twenty-four multiparous Holstein cows were blocked by body condition score and 305-d mature-equivalent milk yield and randomly assigned at calving to 1 of 4 treatments. Treatments were continuous intrajugular infusion of glucose (GI) or isotonic saline (SI), and diets containing high starch, low crude protein (HSLP) or high crude protein, low starch (HPLS) concentrations. Treatments were initiated at the first scheduled feeding following parturition and lasted 12 d. The GI reduced cumulative dry matter intake and tended to reduce daily dry matter intake and meal size for HPLS but not HSLP compared with SI. The GI increased cumulative milk yield by 39 kg/12 d compared with SI by increasing it for HSLP but not HPLS. The HPLS treatment tended to increase loss of body condition from 0.65 to 0.82 body condition score units/12 d compared with HSLP. Consistent with this, HPLS increased plasma concentrations of nonesterified fatty acids, β-hydroxybutyrate, liver triglyceride, milk fat concentration and yield, 3.5% fat-corrected milk, and milk urea nitrogen compared with HSLP. Overall, the GI-HPLS treatment reduced feed intake by reducing meal size. The GI-HPLS may have reduced meal size by the independent or additive effects of (1) decreasing hepatic gluconeogenesis and promoting oxidation of acetyl coenzyme A (CoA), (2) elevated plasma nonesterified fatty acids from HPLS increasing the pool of acetyl CoA available to be oxidized, and (3) the HPLS diet increasing urea synthesis, which also provides the tricarboxylic acid cycle intermediate fumarate to promote oxidation of acetyl CoA. [ABSTRACT FROM AUTHOR]

The Fisher-Widom (FW) line is the locus of points in the density-temperature (rho, T) plane where the longest range decay of the pairwise correlation function of a fluid crosses over from monotonic to damped oscillatory decay. The FW line for a hard-core potential with an attractive Yukawa tail is calculated using two integral equation theories, the random phase approximation and the mean spherical approximation. Although the pole structure of the structure factor in this fluid is similar to that determined for model fluids with finite ranged potentials, the FW line is shifted far from the critical point and intersects the liquid branch of the coexistence curve at a much lower reduced temperature T/Tc than is found for the square-well or truncated Lennard-Jones models. The dependence of the FW line on the choice of model and approximate theory is discussed. [ABSTRACT FROM AUTHOR]

What are biominerals and how are they formed? It is usually assumed: (i) that the prototype for most apatitic biominerals is hydroxyapatite (OHAp), Ca5(PO4)3OH; and (ii) that the OHAp structure has been modified by the presence of impurity ions and vacancy defects in specific OHAp lattice sites. The usual answer, at least implicitly, to the second question is that the apatitic mineral is formed directly by the precipitation of ions from the surrounding solution. Our answers are: (i) that apatitic biominerals are formed through a precursor mechanism in which octacalcium phosphate (OCP), Ca8H2(PO4)6·5H2O, precipitates first and then hydrolyzes irreversibly in situ to a transition product intermediate to OCP and OHAp; and (ii) that this product, "octacalcium phosphate hydrolyzate" (OCPH), may contain (a) OHAp-like and OCP-like domains in varying amounts, (b) vacancy defects and impurity ions in lattice sites in these domains, and (c) various kinds of one-, two-, and three-dimensional defects which are not present in either the OHAp or the OCP lattice, these defects being formed during the in situ hydrolysis step. A calcification model of this type was first proposed in 1957, but full acceptance was delayed because most of the evidence was circumstantial and in vitro in nature. The situation has changed radically because of three unrelated studies that are in vivo in nature but lead to the same conclusion: I. 32P-pyrolysis studies of rat enamel: The results clearly demonstrated that an acidic calcium phosphate precursor was involved. II. Precipitation of calcium phosphates in serum. Ultrafiltered serum was equilibrated with brushite. Subsequent changes in the ionic concentrations revealed that OCP was formed at first and then hydrolyzed to a more basic form, OCPH, but never reached the solubility of OHAp. III. Physicochemical properties of cardiovascular biominerals: We recently characterized biominerals in cardiovascular deposits in an encompassing variety of ways. As an overall conclusion, OCPH was the prototype most compatible with the data [including indices of refraction, solubility, P2O74- formation on pyrolysis, thermogravimetric analysis (TGA) measurements, presence of water, and incorporation of CO32-, Na+, and Mg2+]. This calcification model has important consequences relative to all kinds of calcification and decalcification processes, including those of enamel. [ABSTRACT FROM AUTHOR]

A better knowledge of the pathological calcification mechanisms should provide a rational basis for their control. In the present study, dicalcium phosphate dihydrate (DCPD, CaHPO4 X 2H2O) was used as a source of calcium and phosphate ions to investigate the mechanism of formation of more basic and more insoluble calcium phosphates in ultrafiltered serum (u.f.s.). DCPD crystals were suspended in u.f.s. at 37 degrees C by constant stirring; samples were removed periodically for calcium and phosphate analysis and pH measurement. Occasionally, samples of solids were removed for X-ray diffraction. The experiments were carried out both with and without a 5.5% CO2 atmosphere. After initially becoming saturated with DCPD, the u.f.s. composition changed and became saturated with respect to octacalcium phosphate (OCP, Ca8H2(PO4)6 X 5H2O). At this point OCP crystals were detected in the solid phase by X-ray diffraction. Further stirring changed the composition so that it became undersaturated with both DCPD and OCP and shifted toward, but did not reach, a value so low as to be saturated with hydroxyapatite (OHAp, (Ca5(PO4)3OH). The presence of CO2 in the atmosphere slowed down, but did not prevent, the above sequence of events. The above results strongly suggest that calcifications, beneficial and pathological, that take place in serum may involve OCP as a precursor, which hydrolyzes in situ to a more basic apatitic product. The results also indicate that direct formation of OHAp in u.f.s. is a very slow process and may occur only rarely. The process appears to be similar in whole serum. [ABSTRACT FROM AUTHOR]

Calcifications occurring in arteriosclerotic plaque and other pathological deposits are important health concerns, and the nature of these deposits and their mechanisms of formation warrant investigation. Crystals of the relevant calcium phosphates were equilibrated with the undiluted ultrafiltered human serum (u.f.s.) at 37 degrees C by constant stirring and periodically removing samples for calcium and phosphate analysis and for pH measurement. The solubility measurements were carried out both with and without a 5.5% CO2 atmosphere, the physiological partial pressure of CO2. The apparent ion activity products of well-crystallized dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), and hydroxyapatite (OHAp) equilibrated in u.f.s. were calculated from the calcium and phosphate concentrations and pH in each case for comparison with their known solubility products. In this way the well-crystallized calcium phosphates serve as fiducial solubility standards, thereby minimizing errors due to complexing of calcium and phosphate ions by u.f.s. constituents. Under 5.5%, CO2 native u.f.s. was found to be substantially undersaturated with respect to DCPD, slightly supersaturated with respect to OCP, and highly supersaturated with respect to OHAp. The ion activity product of DCPD in DCPD-saturated u.f.s. was 2.4 X 10(-7), and the ion activity product of OCP in OCP-saturated u.f.s. was 4 X 10(-49), slightly above their solubility products (Ksp(DCPD) = 2.3 X 10(-7), Ksp(OCP) = 2.5 X 10(-49). The ion activity products of DCPD and OCP in u.f.s. under CO2 indicate that the concentrations of calcium and phosphate complexing agents (except bicarbonate) are quite low. The u.f.s. remained supersaturated with respect to OHAp even after 2 months of equilibration.(ABSTRACT TRUNCATED AT 250 WORDS) [ABSTRACT FROM AUTHOR]

Thirty-one patients with sphenoid sinusitis were treated from 1978-1982. Twenty patients had infections contiguous with other paranasal sinus disease. Five of these patients had fungal sinusitis. Eleven patients were seen with isolated sphenoid sinusitis; 3 were secondary to trauma and 8 were due to nontraumatic causes. Possible etiologies include upper respiratory infections, developmental abnormalities, and water forced into the nasal cavity during swimming. The immunocompromised patient is more likely to present with minimal symptoms with a fungal infection, and aggressive diagnostic and therapeutic measures should be undertaken. Because the symptoms of headache, nasal stuffiness, proptosis, ptosis and decreased visual acuity may be interpreted as an intracranial, neurological, or vascular problem, a misdiagnosis may be made. A high index of suspicion for sphenoiditis should be maintained. Therapy involves a combination of medical (antimicrobial agent) and surgical (sinus drainage and marsupialization) management. [ABSTRACT FROM AUTHOR]

Of all angiofibromas, 10% to 20% may have intracranial extensions or receive vascular supply from the internal carotid artery. Until recently, the treatment of intracranial involvement has been radiation therapy. However, with improved anesthetic and neurosurgical techniques, transfusion capabilities and embolotherapy, the combined intracranial and extracranial excision of an angiofibroma has resulted in a low morbidity and mortality and a greater chance for complete excision of the tumor. The authors present the management of three patients with intracranial involvement of their tumors. Use of the midfacial degloving approach to the nasal cavity and paranasal sinuses has resulted in a significant improvement in the cosmetic appearance postoperatively. [ABSTRACT FROM AUTHOR]

Containers to protect food against the ravages of the environment have been used for centuries. Many such containers exclude oxygen efficiently to protect flavor, color, odor, texture, and human health. Food processors and sellers alike often want to convey longer shelf-lives to their products to smooth out the supply/demand balance, to allow wider distribution from larger plants, and to permit advantageous use of resources including the foods themselves. These longer shelf-lives must exceed the likely inventory time to consumption. Coupled with this interest in barrier containers is the need for minimum containment per unit of product packaged. Minimum containment includes both volume and weight to provide for efficient use of space and shipping. [ABSTRACT FROM PUBLISHER]

Setting reactions and compressive strengths of a self-hardening calcium phosphate cement (CPC) were investigated. The CPC consists of tetracalcium phosphate (TTCP) and anhydrous dicalcium phosphate (DCPA). The cement specimens were prepared by mixing 0.7 g of the powder (TTCP 72.9 wt% + DCPA 27.1 wt%) with 0.175 mL of the liquid (25 mmol/L H3P04 and 1.32 mmol/L sodium fluoride). The specimens were removed from the molds at pre-determined time intervals after being mixed, and their compressive strengths were measured. Immediately afterward, the fractured specimens were rapidly frozen in ethanol (- 80°C), lyophilized, and examined by powder x-ray diffraction and scanning electron microscopy (SEM). The results showed that (1) hydroxyapatite was the only reaction product; (2) the reaction was nearly completed within four h, during which both the reaction product and compressive strength increased linearly with time, resulting in a strong correlation between the two; and (3) fully set CPC consisted primarily of small rod-like crystals and some platy crystals. [ABSTRACT FROM AUTHOR]

In this study, the physicochemical factors responsible for caries-like lesion propagation were investigated by means of a micro-analytical system used to study the fluid within a lesion during a simulation of the decay process. Four 500-µm-thick serial sections prepared from a single human molar were mounted between glass plates with only the natural surface of the tooth exposed. Microwells were then drilled into sound and pre-existing carious regions of the section through one of the plates. These microwells were then filled with fluid under mineral oil, and after a week of equilibration, the natural surface of the section was exposed to a lesion-producing fluid. The concentrations of calcium, phosphate, and hydrogen ions of the fluid in the wells were then followed as a function of time as the lesion advanced. The results of this study, in which lactic acid was used to demineralize enamel, were consistent with those previously reported (Vogel et al., 1987a): The solution within the lesion remained saturated during the acid attack Differences in initial mobilities of the calcium and phosphate and other ions, a result of the permselectivity of the enamel, increased the concentrations within the lesion and permanently changed the ratio of these ions in the lesion solution. Based on these results, we suggest that the ionic permselectivity of tooth enamel can have a profound effect on the transport of mineral from a caries lesion. [ABSTRACT FROM AUTHOR]

This paper describes the use of micro-electrodes for the analysis of small fluid volumes recovered from the oral environment. The analysis has several advantages: (1) It directly measures the activity of ions, a quantity more relevant to mineral saturation than the conventionally measured concentration, (2) minimum fluid volume for analysis is usually less than 0. 005 µL, small enough to avoid sample pooling in most analyses, (3) numerous ions can be measured simultaneously, (4) the analysis time is very short, and (5) the use of mineral oil to isolate specimens provides a simple method for controlling the CO2 tension and humidity over the specimens. [ABSTRACT FROM AUTHOR]

Application of DCPD-forming solutions has been shown to increase substantially the enamel reactivity toward F. The effectiveness of a variation of this treatment procedure, in which the DCPD-forming solution was replaced by a viscous carboxymethylcellulose gel containing monocalcium phosphate monohydrate (MCPM), was evaluated by use of 12 extracted human molars. The MCPM gel was highly effective in enhancing the F uptake by enamel. The mean F uptakes by teeth treated with MCPM gel, followed by exposure to a F solution, were 3972 (±565), 2383 (± 312), and 1751 (± 313) ppm, respectively, in the outer 5-, 10-, and 15-µm depths in enamel. These uptakes were2374, 1273, and 852 ppm morethan those of the control teeth. Because the F solution was undersaturated with respect to CaF2, the F incorporated into the enamel was believed to be in apatitic form and not as CaF2. The MCPM gel has advantages over the DCPD-forming solution because (1) much longer gel-tooth contact times can be achieved, and (2) the treatment agent can readily be delivered to specific sites where the tooth needs the protection most. [ABSTRACT FROM AUTHOR]

In an earlier paper on bench-scale simulation of the caries process, it was shown that the passage of ions through ion-permselective barriers could have profound effects on the composition of the solution within the "lesion" at steady state. As indicated in earlier papers, these changes are produced by unequal rates of diffusion of Ca and PO4 ions prior to reaching steady state. Comparable effects are attributable to F ions when present. Here, we used the same two-compartment diffusion apparatus and membranes, as described in the earlier paper, to show that a neutral salt, such as NaCl, disproportionates under the influence of membrane potential. Thus, although the Na and Cl concentrations are nearly equal in the "plaque-saliva" compartment, they become very different in the "lesion" solution. An excess of Na over Cl is equivalent to the presence of the component NaOH, and an excess of Cl over Na is equivalent to the presence of HCl. With the highly permselective commercial membranes used in these experiments, the Ca/P ratio in the "lesion" solution changed from an initial value of 1.6 to a value as high as 53 or as low as 0.1 at steady state. These phenomena are relevant to the events taking place in a caries lesion and must be taken into account in devising physicochemical models of the caries process. A valid caries model, in turn, offers the possibility of identifying steps in the caries mechanism which might be blocked to prevent tooth decay. [ABSTRACT FROM AUTHOR]

A highly parallel incident x-ray beam combined with x-ray image magnification was used to obtain high-resolution microradiographs of dental specimens. Preliminary results obtained using a rotating anode x-ray generator show that limitations associated with conventional contact microradiography regarding (1) spatial resolution, (2) sample thickness, and (3) sample orientation, relative to the film, were significantly reduced. [ABSTRACT FROM AUTHOR]

Effects of temperature (25 and 37°C), pH (4.9-10.5), and CaF2 on CaHP04⋅2H2O (DCPD) hydrolysis were studied in a pH-stat. Octa-calcium phosphate (OCP) was the product at pH 6.2-6.8 and 25- 37°C; thermodynamically stable apatitic compounds were formed at higher pH and/or higher temperature. In the presence of CaF2, apatite was the product, its crystallinity improved, and the fluoride content increased as pH of the reaction decreased. The results demonstrate the remarkable ability of fluoride to promote the hydrolysis of an acidic calcium phosphate, DCPD, to apatite. [ABSTRACT FROM AUTHOR]

Oral rinses which included (1) an acidic calcium phosphate solution containing 0.7 M Ca, 1.9 M P04, and saturated with respect to CaHPO4 ⋅ 2H20, and with a pH of 2.0, followed by (2) a 0.52 M fluoride solution, from NaF or SnF2, were provided to rats once daily for seven days. The investigation consisted of two studies: In the first study, the amounts of dental plaque on the tooth surfaces and fluoride concentrations in the outer enamel were assessed seven days after the last treatment; in the second study, the extent of dental caries was evaluated seven weeks after the last treatment. All rinse sequences containing fluoride provided significant caries protection. The acidic calcium phosphate treatment markedly enhanced the ability of the enamel to acquire fluoride without change of surface morphology. Only the rinse sequences that included stannous fluoride showed significant plaque suppression. [ABSTRACT FROM AUTHOR]

A diffusion cell comprising two compartments separated by a commercial membrane of known ion perm selectivity was used as an experimental model to study factors which may affect caries formation. One compartment (the "lesion ") contained an excess of hydroxyapatite or fluorapatite crystals, and its solution was kept near saturation by stirring. An unsaturated acidic calcium phosphate solution flowed continuously through the other compartment (the "plaque-saliva"), thus providing the driving force for dissolution of the crystals as modified by the permeability of the membrane and/or the presence of fluoride. Calcium, phosphate, fluoride, and chloride concentrations, pH, and membrane potential were measured at steady state. The permselective character of the membrane profoundly affected the solution in the "lesion ": The initial Ca/P ratio of 1.6 was shifted, at steady state, to less than 1.1 ("neutral" membrane), to less than 0.48 (cation-permselective membrane), and to 3.3 (anion-permselective membrane). All the membranes caused Ca and PO4 concentrations in the "lesion" to increase (e.g., with the cation-permselective membrane, the Ca 22-fold and the PO4 75-fold). Substantial membrane potentials were encountered in all cases. The pH of the steady-state solution was always less than before diffusion was initiated; the average decrease was 1.1 units. In every case, the pH, and the Ca and PO4 concentrations of the F--containing solution were less than those in the F--free solution. The changes induced by the "neutral" membrane were unexpectedly large. In two cases, H3PO4 was diffusing against its chemical potential gradient at steady state. The results are relevant for understanding and for modeling of the caries process. [ABSTRACT FROM AUTHOR]