Environmental Control of Phosphorus Acquisition: A Piece of the Molecular Framework Underlying Nutritional Homeostasis.

Homeostasis of phosphorus (P), an essential macronutrient, is vital for plant growth under diverse environmental conditions. Although plants acquire P from the soil as inorganic phosphate (Pi), its availability is generally limited. Therefore, plants employ mechanisms involving various Pi transporters that facilitate efficient Pi uptake against a steep concentration gradient across the plant-soil interface. Among the different types of Pi transporters in plants, some members of the PHOSPHATE TRANSPORTER 1 (PHT1) family, present in the plasma membrane of root epidermal cells and root hairs, are chiefly responsible for Pi uptake from the rhizosphere. Therefore, accurate regulation of PHT1 expression is crucial for the maintenance of P homeostasis. Previous investigations positioned the Pi-dependent posttranslational regulation of PHOSPHATE STARVATION RESPONSE 1 (PHR1) transcription factor activity at the center of the regulatory mechanism controlling PHT1 expression and P homeostasis; however, recent studies indicate that several other factors also regulate the expression of PHT1 to modulate P acquisition and sustain P homeostasis against environmental fluctuations. Together with PHR1, several transcription factors that mediate the availability of other nutrients (such as nitrogen and zinc), light, and stress signals form an intricate transcriptional network to maintain P homeostasis under highly diverse environments. In this review, we summarize this intricate transcriptional network for the maintenance of P homeostasis under different environmental conditions, with a main focus on the mechanisms identified in Arabidopsis.

Capability of Penicillium oxalicum y2 to release phosphate from different insoluble phosphorus sources and soil.

Due to insufficient amount of soluble phosphate and poor persistence of traditional chemical phosphate fertilizers in agricultural soils, the eco-friendly and sustainable phosphorus sources for crops are urgently required. The efficient phosphate-releasing fungal strain designated y2 was isolated and identified by the internal transcribed spacer of rDNA as Penicillium oxalicum y2. When lecithin, Ca3(PO4)2, or ground phosphate rock were separately used as sole phosphorus source, different phosphate-releasing modes were observed. The strain y2 was able to release as high as 2090 mg/L soluble phosphate within 12 days of incubation with Ca3(PO4)2 as sole phosphorus source. In the culture solution, high concentration of oxalic, citric, and malic acids and high phosphatase activity were detected. The organic acids contributed to solubilizing inorganic phosphate sources, while phosphatase was in charge of the mineralization of organic phosphorus lecithin. Afterwards, the fungus culture was applied to the soil with rape growing. During 50 days of incubation, the soil's available phosphate concentration increased by three times compared with the control, the dry weight of rape increased by 78.73%, and the root length increased by 38.79%. The results illustrated that P. oxalicum y2 possessed both abilities of solubilizing inorganic phosphorus and mineralizing organic phosphorus, which have great potential application in providing biofertilizer for modern agriculture.

Role of root exudates on assimilation of phosphorus in young and old Arabidopsis thaliana plants.

The role of root exudates has long been recognized for its potential to improve nutrient use efficiency in cropping systems. However, studies addressing the variability of root exudates involved in phosphorus solubilization across plant developmental stages remain scarce. Here, we grew Arabidopsis thaliana seedlings in sterile liquid culture with a low, medium, or high concentration of phosphate and measured the composition of the root exudate at seedling, vegetative, and bolting stages. The exudates changed in response to the incremental addition of phosphorus, starting from the vegetative stage. Specific metabolites decreased in relation to phosphate concentration supplementation at specific stages of development. Some of those metabolites were tested for their phosphate solubilizing activity, and 3-hydroxypropionic acid, malic acid, and nicotinic acid were able to solubilize calcium phosphate from both solid and liquid media. In summary, our data suggest that plants can release distinct compounds to deal with phosphorus deficiency needs influenced by the phosphorus nutritional status at varying developmental stages.

Metabolomic markers and physiological adaptations for high phosphate utilization efficiency in rice.

Utilizing phosphate more efficiently is crucial for sustainable crop production. Highly efficient rice (Oryza sativa) cultivars have been identified and this study aims to identify metabolic markers associated with P utilization efficiency (PUE). P deficiency generally reduced leaf P concentrations and CO2 assimilation rates but efficient cultivars were reducing leaf P concentrations further than inefficient ones while maintaining similar CO2 assimilation rates. Adaptive changes in carbon metabolism were detected but equally in efficient and inefficient cultivar groups. Groups furthermore did not differ with respect to partial substitutions of phospholipids by sulfo- and galactolipids. Metabolites significantly more abundant in the efficient group, such as sinapate, benzoate and glucoronate, were related to antioxidant defence and may help alleviating oxidative stress caused by P deficiency. Sugar alcohols ribitol and threitol were another marker metabolite for higher phosphate efficiency as were several amino acids, especially threonine. Since these metabolites are not known to be associated with P deficiency, they may provide novel clues for the selection of more P efficient genotypes. In conclusion, metabolite signatures detected here were not related to phosphate metabolism but rather helped P efficient lines to keep vital processes functional under the adverse conditions of P starvation.

Aluminium in plasma and tissues after intramuscular injection of adjuvanted human vaccines in rats.

Aluminium (Al) toxicokinetics after intramuscular (IM) injection of Al-adjuvanted vaccines is unknown. Since animal data are required for modeling and extrapolation, a rat study was conducted measuring Al in plasma and tissues after IM injection of either plain Al-hydroxide (pAH) or Al-phosphate (pAP) adjuvant (Al dose 1.25 mg), single human doses of three Al-adjuvanted vaccines (V1, V2, and V3; Al doses 0.5-0.82 mg), or vehicle (saline). A significant increase in Al plasma levels compared to controls was observed after pAP (AUC(0-80 d), mean ± SD: 2424 ± 496 vs. 1744 ± 508 µg/L*d). Percentage of Al dose released from injected muscle until day 80 was higher after pAP (66.9%) and AP-adjuvanted V3 (85.5%) than after pAH and AH-adjuvanted V1 (0 and 22.3%, resp.). Estimated absolute Al release was highest for pAP (836.8 µg per rat). Al concentration in humerus bone was increased in all groups, again strongest in the pAP group [3.35 ± 0.39 vs. 0.05 ± 0.06 µg/g wet weight (ww)]. Extrapolated amounts in whole skeleton corresponded to 5-12% of the released Al dose. Very low brain Al concentrations were observed in all groups (adjuvant group means 0.14-0.29 µg/g ww; control 0.13 ± 0.04 µg/g ww). The results demonstrate systemically available Al from marketed vaccines in rats being mainly detectable in bone. Al release appears to be faster from AP- than AH-adjuvants. Dose scaling to human adults suggests that increase of Al in plasma and tissues after single vaccinations will be indistinguishable from baseline levels.

Alternative Splicing Plays a Critical Role in Maintaining Mineral Nutrient Homeostasis in Rice (Oryza sativa).

Alternative splicing (AS) of pre-mRNAs promotes transcriptome and proteome diversity and plays important roles in a wide range of biological processes. However, the role of AS in maintaining mineral nutrient homeostasis in plants is largely unknown. To clarify this role, we obtained whole transcriptome RNA sequencing data from rice (Oryza sativa) roots grown in the presence or absence of several mineral nutrients (Fe, Zn, Cu, Mn, and P). Our systematic analysis revealed 13,291 alternatively spliced genes, representing ∼53.3% of the multiexon genes in the rice genome. As the overlap between differentially expressed genes and differentially alternatively spliced genes is small, a molecular understanding of the plant's response to mineral deficiency is limited by analyzing differentially expressed genes alone. We found that the targets of AS are highly nutrient-specific. To verify the role of AS in mineral nutrition, we characterized mutants in genes encoding Ser/Arg (SR) proteins that function in AS. We identified several SR proteins as critical regulators of Zn, Mn, and P nutrition and showed that three SR protein-encoding genes regulate P uptake and remobilization between leaves and shoots of rice, demonstrating that AS has a key role in regulating mineral nutrient homeostasis in rice.

Renal phosphorus excretion in adult healthy cats after the intake of high phosphorus diets with either calcium monophosphate or sodium monophosphate.

Renal and faecal phosphorus excretion of adult healthy European shorthaired cats after the intake of high phosphorus diets (meat/rice based) with either calcium monophosphate (HP-CaP) or sodium monophosphate (HP-NaP) as main phosphorus source was compared. The control diets (CON-CaP and CON-NaP, respectively) did not contain any added phosphorus. Calcium/phosphorus ratio was adjusted to 1.3/1 by adding calcium carbonate. Twenty-three cats were available for the trials. All cats were fed the control diets for 29 days; then, the HP diets were tested for 29 days against controls in a crossover design. Faeces and urine were collected in the last 10 days of each trial. Phosphorus in food, faeces and urine was measured by photometry after wet digestion. Phosphorus intake amounted to 84 ± 10 mg/kg body weight (BW) in CON-NaP (n = 13) and to 74 ± 7 in CON-CaP (n = 12). In the HP groups, the intake was 255 ± 34 mg/kg BW (HP-NaP; n = 13) and 216 ± 20 mg/kg BW (HP-CaP; n = 12). The sodium monophosphate in group HP-NaP led to a higher renal phosphorus excretion (83 ± 15 mg/kg BW) than the calcium monophosphate (25 ± 5 mg/kg BW; p < 0.05), even though the apparent phosphorus digestibility was higher in HP-CaP than in HP-NaP (p < 0.05). Faecal calcium excretion was strictly correlated to faecal phosphorus excretion (r2  = 0.98). The same was true for calcium and phosphorus balance (r2  = 0.89). In group HP-NaP, seven of 13 cats showed glucosuria. By contrast, in HP-CaP glucosuria was not observed. Highly water-soluble inorganic phosphorus sources such as sodium phosphate are likely to lead to phosphaturia and may present a risk for renal health of cats.

Combined application of bio-organic phosphate and phosphorus solubilizing bacteria (Bacillus strain MWT 14) improve the performance of bread wheat with low fertilizer input under an arid climate.

This study was aimed to investigate the effect of bio-organic phosphate either alone or in combination with phosphorus solubilizing bacteria strain (Bacillus MWT-14) on the growth and productivity of two wheat cultivars (Galaxy-2013 and Punjab-2011) along with recommended (150-100NPkgha-1) and half dose (75-50NPkgha-1) of fertilizers. The combined application of bio-organic phosphate and the phosphorous solubilizing bacteria strain at either fertilizer level significantly improved the growth, yield parameters and productivity of both wheat cultivars compared to non-inoculated control treatments. The cultivar Punjab-2011 produced the higher chlorophyll contents, crop growth rate, and the straw yield at half dose of NP fertilizer; while Galaxy-2013, with the combined application of bio-organic phosphate and phosphorous solubilizing bacteria under recommended NP fertilizer dose. Combined over both NP fertilizer levels, the combined use of bio-organic phosphate and phosphorous solubilizing bacteria enhanced the grain yield of cultivar Galaxy-2013 by 54.3% and that of cultivar Punjab-2011 by 83.3%. The combined application of bio-organic phosphate and phosphorous solubilizing bacteria also increased the population of phosphorous solubilizing bacteria, the soil organic matter and phosphorous contents in the soil. In conclusion, the combined application of bio-organic phosphate and phosphorous solubilizing bacteria offers an eco-friendly option to harvest the better wheat yield with low fertilizer input under arid climate.

Combined application of bio-organic phosphate and phosphorus solubilizing bacteria (Bacillus strain MWT 14) improve the performance of bread wheat with low fertilizer input under an arid climate

Abstract This study was aimed to investigate the effect of bio-organic phosphate either alone or in combination with phosphorus solubilizing bacteria strain (Bacillus MWT-14) on the growth and productivity of two wheat cultivars (Galaxy-2013 and Punjab-2011) along with recommended (150-100 NP kg ha−1) and half dose (75-50 NP kg ha−1) of fertilizers. The combined application of bio-organic phosphate and the phosphorous solubilizing bacteria strain at either fertilizer level significantly improved the growth, yield parameters and productivity of both wheat cultivars compared to non-inoculated control treatments. The cultivar Punjab-2011 produced the higher chlorophyll contents, crop growth rate, and the straw yield at half dose of NP fertilizer; while Galaxy-2013, with the combined application of bio-organic phosphate and phosphorous solubilizing bacteria under recommended NP fertilizer dose. Combined over both NP fertilizer levels, the combined use of bio-organic phosphate and phosphorous solubilizing bacteria enhanced the grain yield of cultivar Galaxy-2013 by 54.3% and that of cultivar Punjab-2011 by 83.3%. The combined application of bio-organic phosphate and phosphorous solubilizing bacteria also increased the population of phosphorous solubilizing bacteria, the soil organic matter and phosphorous contents in the soil. In conclusion, the combined application of bio-organic phosphate and phosphorous solubilizing bacteria offers an eco-friendly option to harvest the better wheat yield with low fertilizer input under arid climate.

Insight into the cellular fate and toxicity of aluminium adjuvants used in clinically approved human vaccinations.

Aluminium adjuvants remain the most widely used and effective adjuvants in vaccination and immunotherapy. Herein, the particle size distribution (PSD) of aluminium oxyhydroxide and aluminium hydroxyphosphate adjuvants was elucidated in attempt to correlate these properties with the biological responses observed post vaccination. Heightened solubility and potentially the generation of Al(3+) in the lysosomal environment were positively correlated with an increase in cell mortality in vitro, potentially generating a greater inflammatory response at the site of simulated injection. The cellular uptake of aluminium based adjuvants (ABAs) used in clinically approved vaccinations are compared to a commonly used experimental ABA, in an in vitro THP-1 cell model. Using lumogallion as a direct-fluorescent molecular probe for aluminium, complemented with transmission electron microscopy provides further insight into the morphology of internalised particulates, driven by the physicochemical variations of the ABAs investigated. We demonstrate that not all aluminium adjuvants are equal neither in terms of their physical properties nor their biological reactivity and potential toxicities both at the injection site and beyond. High loading of aluminium oxyhydroxide in the cytoplasm of THP-1 cells without immediate cytotoxicity might predispose this form of aluminium adjuvant to its subsequent transport throughout the body including access to the brain.

Phosphate removal from water by a novel zeolite/lanthanum hydroxide hybrid material prepared from coal fly ash.

This study was undertaken to investigate the effectiveness of the hybrid adsorbent, which was synthesized from coal fly ash and was composed of lanthanum hydroxide and zeolite (La-ZFA), for phosphate removal from water. Long-term repeated adsorption tests for 30 days showed that the maximum removal capacity of the material reached 66.09 mg P/g. The fractionation of adsorbed phosphorus indicated that phosphate immobilized by La-ZFA was quite irreversible and was dominated by HCl-P fraction. It was suggested that the immobilization of phosphate was mainly attributed to lanthanum hydroxide and was slightly influenced by coexistence of other anions (Cl(-), NO3(-), SO4(2-), and HCO3(-)). At a La/P molar ratio between 1.5:1 and 2.0:1, a nearly complete removal (above 98%) of phosphate could be achieved. La-ZFA also exhibited great performance for removing phosphate from lake water (97.29%) as well as the effluent from wastewater treatment plant (97.86%), respectively. In addition, based on the results of the present study, it was believed that La-ZFA could be a potential material for phosphate removal in practical application.

[Phosphate Intoxication after Application of Enema--a Life-threatening Iatrogenic Complication]. / Phosphatintoxikation nach Klysmagabe--eine lebensgefährliche iatrogene Komplikation.

INTRODUCTION: Enemas are used in pediatric patients with constipation. Retention of phosphate containing enemas with prolonged resorption or reduced renal elimination of phosphate can result in life-threatening hyperphosphatemia with subsequent lethal hypocalcemia and acidosis. CASE PRESENTATION: We report the case of a 6-month-old child who received phosphate-containing enema to treat acute aggravation of constipation. The used enema here was not licensed for this age group. Phosphate intoxication resulted (phosphate 19.87 mmol/l) and presented like a sepsis. Hyperphosphatemia was treated by hemodialysis. A non-diagnosed Hirschsprung disease had led to prolonged resorption of phosphate containing enema and to an ileus and toxic megacolon that had to be operated. CONCLUSION: Insufficient elimination of phosphate containing enema can result in lethal or life threatening hyperphosphatemia, hypocalcemia and metabolic acidosis. These can be treated efficaciously by hemodialysis. Because of the high risk of intoxication in using enemas containing phosphate in infants or in patients with gastrointestinal or renal comorbidities, physicians treating constipation should choose enemas without phosphate but with ingredients with lower risk like glycerol or sorbitol in this age group.

Al adjuvants can be tracked in viable cells by lumogallion staining.

The mechanism behind the adjuvant effect of aluminum salts is poorly understood notwithstanding that aluminum salts have been used for decades in clinical vaccines. In an aqueous environment and at a nearly neutral pH, the aluminum salts form particulate aggregates, and one plausible explanation of the lack of information regarding the mechanisms could be the absence of an efficient method of tracking phagocytosed aluminum adjuvants and thereby the intracellular location of the adjuvant. In this paper, we want to report upon the use of lumogallion staining enabling the detection of phagocytosed aluminum adjuvants inside viable cells. Including micromolar concentrations of lumogallion in the culture medium resulted in a strong fluorescence signal from cells that had phagocytosed the aluminum adjuvant. The fluorescence appeared as spots in the cytoplasm and by confocal microscopy and co-staining with probes presenting fluorescence in the far-red region of the spectrum, aluminum adjuvants could to a certain extent be identified as localized in acidic vesicles, i.e., lysosomes. Staining and detection of intracellular aluminum adjuvants was achieved not only by diffusion of lumogallion into the cytoplasm, thereby highlighting the presence of the adjuvant, but also by pre-staining the aluminum adjuvant prior to incubation with cells. Pre-staining of aluminum adjuvants resulted in bright fluorescent particulate aggregates that remained fluorescent for weeks and with only a minor reduction of fluorescence upon extensive washing or incubation with cells. Both aluminum oxyhydroxide and aluminum hydroxyphosphate, two of the most commonly used aluminum adjuvants in clinical vaccines, could be pre-stained with lumogallion and were easily tracked intracellularly after incubation with phagocytosing cells. Staining of viable cells using lumogallion will be a useful method in investigations of the mechanisms behind aluminum adjuvants' differentiation of antigen-presenting cells into inflammatory cells. Information will be gained regarding the phagosomal pathways and the events inside the phagosomes, and thereby the ultimate fate of phagocytosed aluminum adjuvants could be resolved.

Effect of orthophosphate and bioavailability of dissolved organic phosphorous compounds to typically harmful cyanobacterium Microcystis aeruginosa.

Results show that Microcystis aeruginosa can utilize both dissolved organic phosphorus (DOP) and orthophosphate (DIP) even under low phosphorus (P) conditions to sustain its growth. Total P concentrations decreased markedly in all three P source treatments. Alkaline phosphatase activity (APA) in the different P sources tested changed in response to the DOP and DIP. The APA of DOP groups remained low after decreasing significantly, but the APA in the DIP treatments remained high during the period of culture. Changes in APA at different PO4(3-)-P concentrations in a culture medium revealed negative correlations between APA and DIP. However, a positive relationship was observed between APA and DOP under low P concentrations. These findings indicate that M. aeruginosa can regulate its physiological metabolism to acclimate to low ambient DIP environments.

Kinetics of phosphate absorption in lactating dairy cows after enteral administration of sodium phosphate or calcium phosphate salts.

Hypophosphataemia is frequently encountered in dairy cows during early lactation. Although supplementation of P is generally recommended, controversy exists over the suitability of oral P supplementation in animals with decreased or absent rumen motility. Since the effects of transruminal P absorption and the reticular groove reflex on the absorption kinetics of P are not well understood, it is unclear in how far treatment efficacy of oral P supplementation is affected by decreased rumen motility. Phosphate absorption was studied in six phosphate-depleted dairy cows fitted with rumen cannulas and treated with test solutions containing either NaH2PO4 or CaHPO4 with acetaminophen. Each animal was treated orally, intraruminally and intra-abomasally in randomised order. Absorption kinetics of P were studied and compared with the absorption kinetics of acetaminophen, a marker substance only absorbed from the small intestine. Intra-abomasal treatment with NaH2PO4 resulted in the most rapid and highest peaks in plasma inorganic P (Pi) concentration. Oral and intraruminal administration of NaH2PO4 resulted in similar increases in plasma Pi concentration from 4 to 7 h in both groups. Treatment with NaH2PO4 caused more pronounced peaks in plasma Pi concentration compared with CaHPO4. Neither transruminal P absorption nor the reticular groove reflex affected P absorption kinetics as determined by comparing plasma concentration­time curves of P and acetaminophen after administration of 1M-phosphate salt solutions. It is concluded that oral treatment with NaH2PO4 but not CaHPO4 is effective in supplementing P in hypophosphataemic cows with adequate rumen motility. Decreased rumen motility is likely to hamper the efficacy of oral phosphate treatment.

Pharmacology of the phosphate binder, lanthanum carbonate.

Studies were conducted to compare the phosphate-binding efficacy of lanthanum carbonate directly with other clinically used phosphate binders and to evaluate any potential adverse pharmacology. To examine the phosphate-binding efficacy, rats with normal renal function and chronic renal failure received lanthanum carbonate, aluminum hydroxide, calcium carbonate, or sevelamer hydrochloride in several experimental models. Lanthanum carbonate and aluminum hydroxide markedly increased excretion of [(32)P]-phosphate in feces and reduced excretion in urine in rats with normal renal function (p < 0.05), indicating good dietary phosphate-binding efficacy. In rats with chronic renal failure, lanthanum carbonate and aluminum hydroxide reduced urinary phosphate excretion to a greater degree and more rapidly than calcium carbonate, which in turn was more effective than sevelamer hydrochloride. The potential to induce adverse pharmacological effects was assessed systematically in mice, rats, and dogs with normal renal function using standard in vivo models. There was no evidence of any adverse secondary pharmacological effects of lanthanum carbonate on the central nervous, cardiovascular, respiratory, or gastrointestinal systems. These studies indicate that lanthanum carbonate is the more potent of the currently available dietary phosphate binders. No adverse secondary pharmacological actions were observed in vivo in a systematic evaluation at high doses.

Serum electrolyte shifts following administration of sodium phosphates enema.

The misuse of sodium phosphates enemas has resulted in reports of potentially severe metabolic and hemodynamic disturbances. Despite their long availability, these products have not been fully characterized pharmacokinetically. This trial sought to evaluate changes in the metabolic and hemodynamic parameters following the administration of one of two standard sodium phosphates enemas. Enema Casen (250 ml) is available only in Spain, and Fleet Enema (133 ml) is available in 66 countries in six continents of the world. These changes were correlated with scientific literature reports of hyperphosphatemia following phosphate enema use. Forty-five adult participants aged 50 years or older enrolled in the trial. Twenty-five participants were given one Enema Casen, whereas 20 participants received one Fleet Enema. Blood pressure, pulse, and serum chemistries were evaluated at screening; baseline; and 10, 60, and 120 minutes after receiving the enema. Each participant had a bowel movement within 10 minutes of receiving his enema. Asymptomatic, transient hyperphosphatemia was associated with increase in retention time but not with increase in volume of sodium phosphates enemas. Increased serum phosphate concentration and increased area under the curve of serum phosphate were associated with increased enema retention time. The Enema Casen induced a greater mean AUC of serum sodium concentration than did the Fleet Enema. There were no drug-related adverse events. Transient hyperphosphatemia following the use of sodium phosphates enemas correlates with retention time but not with dose. A scientific literature review of serious adverse events revealed that overdose, concomitant use of oral and rectal sodium phosphates products, and use in a contraindicated patient were associated with sodium phosphates enema and hyperphosphatemia.

Bowel preparation: comparing metabolic and electrolyte changes when using sodium phosphate/polyethylene glycol.

BACKGROUND: Many patients with various types of colonic pathology undergo invasive procedures that require mechanical bowel preparation. The most commonly used medications for bowel preparation include phosphate-containing drugs which are low cost and enable this procedure to be performed in an outpatient setting, as opposed to other medications, such as polyethylene glycol. Recent studies have suggested that freely using phosphate-containing drugs might lead to renal function impairment in a small group of patients. Despite this, many surgeons still use these drugs to prepare their patients. We conducted a comparative study to check the side effects of phosphate-containing drugs compared to polyethylene glycol when used for bowel cleansing. METHODS: We conducted a double blind prospective randomized study that included 40 patients undergoing surgery for colonic pathology, all of whom underwent bowel cleansing (20 with sodium phosphate and 20 with polyethylene glycol). During the perioperative course, electrolyte parameters were collected from serum and urine and compared between the two groups of patients. RESULTS: Changes in electrolyte and metabolic parameters were shown in both groups, but more prominently in patients prepared with sodium phosphate. In addition, early signs of renal function impairment appeared in this group. The differences in metabolic and electrolyte changes between the two groups were statistically significant. CONCLUSIONS: On the basis of this study, we propose that the wide use of phosphate-containing drugs for colonic preparation might be dangerous for the specific group of patients that is prone to develop renal failure or electrolyte abnormalities.

Forensic application of ESEM and XRF-EDS techniques to a fatal case of sodium phosphate enema intoxication.

Sodium phosphate enemas and laxatives are widely used for the treatment of constipation, even if a number of cases of significant toxicity due to alterations of the fluid and electrolyte equilibria (hypernatremia, hyperphosphatemia, and hypocalcemia) have been reported. We present the case of an 83-year-old man who died of fecal and chemical peritonitis secondary to an iatrogenic colon perforation (produced performing a Fleet enema through the patient's iliac colostomy) with peritoneal absorption of sodium phosphate. Environmental scanning electron microscopy coupled with an X-ray fluorescence energy dispersive spectrometry discovered multiple bright crystals formed of calcium, phosphorus, and oxygen in the brain, heart, lung, and kidney sections of the victim. The absence of these kinds of precipitates in two control samples chronically treated with Fleet enemas led us to assume that the deceased had adsorbed a great quantity of phosphorus ions from the peritoneal cavity with subsequent systemic dissemination and precipitation of calcium phosphate bindings.

Vaginal distribution of Replens and K-Y Jelly using three imaging techniques.

BACKGROUND: Determination of vaginal distribution is important to the development of potential vaginal microbicidal or spermicidal products. STUDY DESIGN: This was a descriptive study of three imaging techniques with a randomized crossover assignment of two gels and activity status within each technique. METHOD: Each of three sites utilized one technique. Three nulligravid women and three parous women were to be enrolled at each site. We studied the effects of time, ambulation, parity and body mass index on vaginal spreading of two commonly used gels, K-Y Jelly and Replens. Imaging by magnetic resonance imaging and gamma scintigraphy was performed at 5, 20, 35 and 50 min after insertion of 3.5 mL of gel. Imaging with a fiberoptic probe was performed at 5 and 20 min after insertion. RESULTS: Initial application of the gel resulted in approximately two thirds of maximum coverage possible, both in linear extent along the vaginal axis and in surface area covered. Over the next 45 min, spreading increased to about three quarters of the maximum possible. Ambulation generally increased linear spreading and the proportions of women with gel at the introitus and os. Effects of parity and body mass index (BMI) were similar on most measures of gel spreading, with nulligravid women tending toward greater spread than parous women and women of high BMI usually showing somewhat greater spread than women of normal weight. Differences between the two gels were not seen when all conditions of application were considered together. CONCLUSION: In vivo imaging of gel distribution demonstrated that ambulation, parity and BMI affect vaginal gel spreading. The three imaging techniques have advantages and disadvantages and provide complementary information for microbicide development.