Monolayers of opossum kidney (OK) cells are widely used as models for the renal proximal tubule. OK cells adapt to phosphate (Pi) depletion by increasing their capacity for apical and basolateral Na⁺-dependent Pi uptake. Because NMR-visible cell Pi was found to be decreased in Pi-deprived kidney cells, we suggested that up-regulation of basolateral Pi efflux also occurs during adaptation to Pi deprivation [American Journal of Physiol 1994;267:C915–919]. In order to test this hypothesis, we measured the cell Pi pool, basolateral Pi efflux and transepithelial Pi fluxes in OK cells grown on permeable plastic filters, exposed overnight to solutions containing either 0.5 mM (deprived) or 2.0 mM (replete) Pi or ³²Pi. Following steady state or acute loading with ³²Pi, the specific activity (SA) of cell Pi, the cell Pi pool and the basolateral efflux of ³²Pi were measured. In the steady state, a 2-fold increase in Pi uptake sustained the intracellular Pi pool at 85% of the control level (30 ± 5 nmol/mg) in spite of a decrease in extracellular Pi from 2 to 0.5 mM. When the extracellular Pi was acutely (1 h) reduced to 0.1 mM, the cell Pi pool decreased (to 3 ± 1 nmol/mg) both in cells previously adapted overnight to either 0.5 or to 2 mM Pi (p >0.3). The rates of absolute and fractional basolateral washout of cell ³²Pi after 1 h loading with 0.1 mM³²Pi were similar in cells adapted to 0.5 compared to 2 mM Pi. This indicates that Pi depletion did not affect the effective permeability of the basolateral membranes to Pi. Adaptation for 16 h to 0.5 compared to 2 mM Pi did not alter the rate of net transepithelial transport of 0.1 mM Pi from the apical to the basal compartment but reduced (p < 0.05) the unidirectional fluxes of both ³²Pi and ¹⁴C-mannitol. An insufficient driving force (unchanged or low Pi concentration in the transport pool, low electrical or coupled-anion gradients) and a constant effective basolateral Pi permeability must have limited basolateral Pi efflux in cells exposed to 0.1 mM Pi. Thus, in OK cells grown on plastic support there are no adaptive increases in either basolateral Pi efflux, or in transcellular and paracellular Pi transport, in response to Pi depletion. Adaptations are limited to increases in apical and basolateral sodium-dependent Pi uptakes that can maintain the cell Pi pool as long as apical Pi is not too low (≧0.5 mM). The OK cells adapt to low Pi concentrations conserving cell Pi but not increasing basolateral Pi efflux nor transepithelial Pi transport.

It is generally assumed that phosphate (Pi) effluxes from proximal tubule cells by passive diffusion across the basolateral (BL) membrane. We explored the mechanism of BL PI efflux in proximal tubule-like OK cells grown on permeable filters and then loaded with 32P. BL efflux of 32P was significantly stimulated (P < 0.05) by exposing the BL side of the monolayer to 12.5 mM Pi, to 10 mM citrate, or by acid-loading the cells, and was inhibited by exposure to 0.05 mM Pi or 25 mM HCO3; by contrast, BL exposure to high (8.4) pH, 40 mM K+, 140 mM Na gluconate (replacing NaCl), 10 mM lactate, 10 mM succinate, or 10 mM glutamate did not affect BL 32P efflux. These data are consistent with BL PI efflux from proximal tubule-like cells occurring, in part, via an electro-neutral sodium-sensitive anion transporter capable of exchanging two moles of intracellular acidic H2PO4– for each mole of extracellular basic HP04– or for citrate.

Background: Malaria is one of the most important infectious inflammatory diseases worldwide which affects vital organs including gastrointestinal and kidneys. Higher prevalence of malaria related renal failure, current malaria drugs nephrotoxicity and drug resistance to malaria calls for continued research in anti-parasitic as well as anti-disease inflammatory pharmaceuticals. Asiatic acid, a plant phytochemical extract, has antioxidant, pro-oxidant and diuretic properties. Here we report influence of Asiatic acid-pectin hydrogel matrix patch application in P. berghei-infected Sprague Dawley rats on renal function and electrolyte handling. Materials and Methods: Asiatic acid (5mg/kg)-pectin patch was applied on the dorsal neck region of the rat on day 7 post infection and monitored for parasitaemia, and physicochemical changes. Urine and blood were collected for measuring various biochemical parameters to estimate renal function and electrolyte handling. Results: Asiatic acid-pectin patch application had significant influence on food and water intake as well as weight changes, urine electrolytes, glomerular filtration rate, and antioxidant markers together with hormonal changes of aldosterone and vasopressin. Conclusion: Application of the once-off Asiatic acid (5mg/kg)-pectin patch influence renal function and renal electrolyte handling while ameliorating, biochemical and hormonal derangements induced by malaria. Novelty of the Work Here we show for the first time a) the efficacy of Asiatic acid (AA) in suppressing murine malaria by way of administering the phytochemical using the amidated pectin hydrogel matrix patch transdermal drug delivery system, b) diminution of asiatic acid dose applied from 10mg/kg oral to 5mg/kg by transdermal, c) reduction of time once-off patch application from five days to three days, d) attenuation of oxidative and hormonal derangements in malaria and e) the amelioration of renal function together with improvement in renal electrolyte handling. The results may be of benefit in patient care replacing the multiple dosing approaches used in malaria management.

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Introduction: Women have psychosocial challenges but perinatal interventions are not making much impact on their mental status hence the interventions need scaling up. This study involved measuring and analysing the extent to which levels of the psychosocial markers reflect effectiveness of the mental health interventions offered by midwives. Methods: The study was conducted at Mpilo Central Hospital Maternity Bulawayo, for the main reason that it receives women referrals from 5 out of the 10 provinces in the country with a total catchment of almost 50% of the country’s population. The maternity hospital has a full complement of all the five maternity units. A quantitative approach administrating a Quality-of-Life Enjoyment and Satisfaction Short form (Q-LES-SF) scale was used. The scale ranged from “very poor” to “very good” with “poor”, “fair”, “good” components in between was used to measure the psychosocial scores on a purposive sample of 300 women in the third trimester of pregnancy. The participants had attended at least three antenatal reviews where psychosocial interventions and mental health assessment, monitoring and evaluations are normally carried. The quantitative data was analysed using descriptive statistics on SPSS Version 23 package. Results: The Q-LES-Q-SF psychosocial scale which was revealed that women had psychosocial challenges without adequate mental health interventions to ameliorate these challenges. The study demonstrated a bimodal sample with peaks at the “Good” and “Poor” set points. The relationships of the psychosocial and satisfaction scores along the scale continuum showed that “Poor” (33%) Q-LES-Q-SF was higher, followed by “Good” (29%), followed by “Fair” (25%), followed by “Very Poor” and “Very Poor” and “Very Good” being equal (6.5%) in a normal distribution pattern. The likelihood of the demographic variables influencing the Q-LES-Q-F scale were not necessarily linked to the quality-of-life enjoyment and satisfaction of the expectant women during prenatal period. However, age, education level acquired and marital status showed a linearity towards the “Good” when individually rated against the Q-LES-Q-F. Discussion: The psychosocial scores were generally both poor and good indicating that perinatal interventions are needed are needed to making much impact on the mental and social wellbeing of women in the third trimester of pregnancy. The good to very good Q-LES-Q-F scores are a requirement in expectant mothers as this has a strong bearing on the wellbeing of the foetus and mother post parturition. Apparently, the need for scaling up psychosocial support, monitoring, evaluation and interventions to third trimester pregnant women by midwives cannot be overemphasized.