Temperature, concentration, and surface modification influence the cellular uptake and the protein corona of polystyrene nanoparticles.

The composition of the protein corona varies depending on several parameters and influences the cellular fate of the nanocarriers. Here, we investigated the influence of three key parameters (surface charge, temperature, and plasma concentration) on the formation and composition of the protein corona of polystyrene nanoparticles and ultimately on the cellular uptake of pre-coated nanoparticles. At a fixed temperature and concentration, the surface charge, and surfactant influence its composition. We observed that the composition of the corona formed at low temperatures (4°C) is different from that formed at physiological temperatures (37°C). At low plasma concentrations (up to 25%), the corona consists of more diverse proteins than at higher concentrations. Finally, we concluded that regardless of the nanoparticle formulation, the degree of uptake by model cancer and endothelial cells of the nanoparticles decreased when pre-coated at increasing temperature or plasma concentration. STATEMENT OF SIGNIFICANCE: Drug delivery through nanocarriers is an increasingly important concept in research and medicine. One problem in the application of nanocarriers in medicine is the protein corona that forms around the nanocarriers when they get in contact with protein-containing fluids. So far, several factors have been identified that influence the composition of the protein corona and thus the biological identity of the particles. However, lacking comparability remains between the studies because different concentrations or temperatures of the protein solutions are used. In this study we demonstrate how the incubation temperature or the concentration of plasma influences the protein corona and thus the cellular uptake of polystyrene nanoparticles.

Genome size shifts: karyotype evolution in Crepis section Neglectoides (Asteraceae).

Plant genome size evolution is a very dynamic process: the ancestral genome of angiosperms was initially most likely small, which led to a tendency towards genome increase during evolution. However, findings in several angiosperm lineages demonstrate mechanisms that also led to genome size contraction. Recent molecular investigations on the Asteraceae genus Crepis suggest that several genomic reduction events have occurred during the evolution of the genus. This study focuses on the Mediterranean Crepis sect. Neglectoides, which includes three species with some of the smallest genomes within the whole genus. Crepis neglecta has the largest genome in sect. Neglectoides, approximately twice the size of the two species Crepis cretica and Crepis hellenica. Whereas C. cretica and C. hellencia are more closely related to each other than to C. neglecta the karyotypes of the latter species and C. cretica are similar, while that of C. hellenica differs considerably. Here, the karyotypic organisation of the three species is investigated with fluorescence in-situ hybridisation and studied in a molecular phylogenetic framework based on the nuclear markers Actin, CHR12, CPN60B, GPCR1 and XTH23. Our findings further corroborate the occurrence of genome size contraction in Crepis, and suggest that the difference in genome size between C. neglecta and C. cretica is mostly due to elimination of dispersed repetitive elements, whereas chromosomal reorganisation was involved in the karyotype formation of C. hellenica.

Estrous cycle variations in GABA(A) receptor phosphorylation enable rapid modulation by anabolic androgenic steroids in the medial preoptic area.

Anabolic androgenic steroids (AAS), synthetic testosterone derivatives that are used for ergogenic purposes, alter neurotransmission and behaviors mediated by GABA(A) receptors. Some of these effects may reflect direct and rapid action of these synthetic steroids at the receptor. The ability of other natural allosteric steroid modulators to alter GABA(A) receptor-mediated currents is dependent upon the phosphorylation state of the receptor complex. Here we show that phosphorylation of the GABA(A) receptor complex immunoprecipitated by ß(2)/ß(3) subunit-specific antibodies from the medial preoptic area (mPOA) of the mouse varies across the estrous cycle; with levels being significantly lower in estrus. Acute exposure to the AAS, 17α-methyltestosterone (17α-MeT), had no effect on the amplitude or kinetics of inhibitory postsynaptic currents in the mPOA of estrous mice when phosphorylation was low, but increased the amplitude of these currents from mice in diestrus, when it was high. Inclusion of the protein kinase C (PKC) inhibitor, calphostin, in the recording pipette eliminated the ability of 17α-MeT to enhance currents from diestrous animals, suggesting that PKC-receptor phosphorylation is critical for the allosteric modulation elicited by AAS during this phase. In addition, a single injection of 17α-MeT was found to impair an mPOA-mediated behavior (nest building) in diestrus, but not in estrus. PKC is known to target specific serine residues in the ß(3) subunit of the GABA(A) receptor. Although phosphorylation of these ß(3) serine residues showed a similar profile across the cycle, as did phosphoserine in mPOA lysates immunoprecipitated with ß2/ß3 antibody (lower in estrus than in diestrus or proestrus), the differences were not significant. These data suggest that the phosphorylation state of the receptor complex regulates both the ability of AAS to modulate receptor function in the mPOA and the expression of a simple mPOA-dependent behavior through a PKC-dependent mechanism that involves the ß(3) subunit and other sites within the GABA(A) receptor complex.

Anabolic androgenic steroid abuse: multiple mechanisms of regulation of GABAergic synapses in neuroendocrine control regions of the rodent forebrain.

Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone originally developed for clinical purposes but are now predominantly taken at suprapharmacological levels as drugs of abuse. To date, almost 100 different AAS compounds that vary in metabolic fate and physiological effects have been designed and synthesised. Although they are administered for their ability to enhance muscle mass and performance, untoward side effects of AAS use include changes in reproductive and sexual behaviours. Specifically, AAS, depending on the type of compound administered, can delay or advance pubertal onset, lead to irregular oestrous cyclicity, diminish male and female sexual behaviours, and accelerate reproductive senescence. Numerous brains regions and neurotransmitter signalling systems are involved in the generation of these behaviours, and are potential targets for both chronic and acute actions of the AAS. However, critical to all of these behaviours is neurotransmission mediated by GABA(A) receptors within a nexus of interconnected forebrain regions that includes the medial preoptic area, the anteroventral periventricular nucleus and the arcuate nucleus of the hypothalamus. We review how exposure to AAS alters GABAergic transmission and neural activity within these forebrain regions, taking advantage of in vitro systems and both wild-type and genetically altered mouse strains, aiming to better understand how these synthetic steroids affect the neural systems that underlie the regulation of reproduction and the expression of sexual behaviours.

Receipt of vaginal-cervical stimulation modifies synapsin content in limbic areas of the female rat.

Female rats require a sufficient amount and pattern of vaginal-cervical stimulation to initiate neuroendocrine changes required for the successful implantation of a fertilized ovum in the uterus. These changes are characterized by twice daily prolactin surges that last 10-12 days. Following a sterile mating, the endocrine changes are still observed, and are termed pseudopregnancy (PSP). The mating stimulation required to initiate these changes prior to pregnancy or PSP has a neural representation, which we have termed the intromission mnemonic. We sought to examine if the formation of the intromission mnemonic is accompanied by alterations in the number or density of synapses in limbic areas by immuno-labeling a pre-synaptic protein, synapsin. Groups of cycling female rats on proestrus day received either 15 or 5 intromissions or mounts-without intromissions from a vasectomized male; an additional time-matched control group was left in the home cage. All females were perfused after 90 min or 8 h. The brains were removed and sliced, and the amygdala and hippocampus immunostained for synapsin, then imaged by confocal microscopy. We found that 90 min after mating sufficient for PSP, the number of synapsin puncta (points of immunoreactivity equivalent to a synapse) was decreased and the intensity of the synapsin staining was increased in the posterodorsal medial amygdala (MePD). A similar reduction of puncta was observed in the CA1 region of the hippocampus, and an increase of intensity occurred in the basolateral amygdala. Spaced intromissions had no effect on synapsin expression anywhere examined. Intensity reductions unrelated to receipt of vaginal-cervical stimulation were observed in the hippocampus. None of these effects were observed after 8 h. Together, these results raise the possibility that synapses in the MePD may be pruned after mating stimulation, resulting in pathway-specific stabilization that contributes to the intromission mnemonic associated with the establishment of PSP.

Capillary endothelia and cardiomyocytes differ in vulnerability to ischemia/reperfusion during clinical heart transplantation.

OBJECTIVE: The development of accelerated graft arteriosclerosis is a major cause of late death after orthotopic heart transplantation. The influence and the extent of peritransplant injury, especially of cardiomyocyte or capillary endothelial cell edema is discussed. METHODS: A morphometric ultrastructural analysis of myocardial biopsies from 29 donor hearts (21 male, age 34+/-11 years) was performed. Right ventricular biopsies were obtained before cardioplegia (A), immediately following cardioplegia (B) (Custodiol, Dr. F. Köhler Chemie GmbH, Alsbach-Hähnlein, Germany), before implantation (C), after 30 (D) or 60 (E) min of reperfusion and 1 week after transplantation (F). Mean ischemic time was 185+/-68 min. Quantitative electron microscopy was carried out in five samples per heart and time point and in 30 test fields per sample by 'random systematic sampling' and 'point and intersection counting'. As parameters for cell edema the volume density of myofibrils in cardiomyocytes and the mean barrier thickness of capillary endothelia were analyzed. P-values of less than 0.05 were regarded as significant. Significant differences in contrast to the previous values are marked by *. RESULTS: The volume density of myofibrils (vol.%) was as follows: (B) 63.6+/-3.2, (C) 61.8+/-3.2, (D) 62.9+/-3.2, (E) 63.6+/-4.5. The mean barrier thickness (nm) was as follows: (A) 353+/-21, (B) 376+/-59, (C) 416+/-71*, (D) 473+/-45*; (E) 453+/-50*, (F) 379+/-39. CONCLUSIONS: Apart from a generally accepted edema of cardiomyocytes a relevant capillary endothelial cell edema develops during clinical heart transplantation. In contrast to cardiomyocytes the cell edema of endothelia shows a more pronounced and significant progression during cold ischemia and early reperfusion. After 60 min of reperfusion it is still significantly more pronounced than at the onset of ischemia. After 1 week there are no statistical differences compared to the initial values. Thus, an edema of capillary endothelia probably will trigger inhomogeneities in capillary perfusion. Peritransplant injury of endothelia may contribute to the later development of accelerated allograft arteriosclerosis.

Rationing medical care: rhetoric and reality in the Oregon Health Plan.

The Oregon Health Plan (OHP) has been widely heralded as an important innovation in medical care policy and rationing. Oregon's pioneering method of prioritizing funding for health care through systematic and public ranking of medical services has drawn substantial international interest. This paper reviews the experience of the Oregon plan since it began operation in 1994. We argue that widespread misconceptions persist about the significance of the OHP. In particular, there is little evidence that the OHP has operated as a model of explicit rationing. In reality, Oregon has not rationed services, nor has its policy of cutting public coverage for services produced substantial savings. These findings have important implications regarding the desirability and feasibility of adopting a policy of removing items from the list of insured medicare services in Canada. Oregon's experience suggests that drawing the line on medicare coverage would be more difficult and less financially rewarding than advocates claim.

Is premium support the right medicine for Medicare?

This paper assesses the desirability of transforming Medicare into a premium-support system. I focus on three areas crucial to the future of Medicare: cost savings, beneficiary choice, and the stability of traditional Medicare. Based on my analysis of the Bipartisan Commission on the Future of Medicare plan, I find substantial problems with adopting premium support for Medicare. In particular, projections of premium-support savings are based on questionable assumptions that the slowdown in health spending during 1993-1997 can be sustained and extrapolated to future Medicare performance. Consequently, premium support may inadvertently destabilize public Medicare and erode beneficiary choice without achieving substantial savings.

The Oregon Health Plan and the political paradox of rationing: what advocates and critics have claimed and what Oregon did.

The article proceeds in three sections. First, we very briefly review the original proposals and ensuing (and misleading) debate over rationing in Oregon. Next, we explore how the politics of rationing unfolded in Oregon from the enactment of OHP to its implementation. Finally, we consider the character of Oregon's innovation and the broader lessons that it holds for reform efforts elsewhere.

Remaking Medicare: the voucher myth.

There is growing enthusiasm for transforming Medicare into a voucher system. Advocates claim vouchers would increase the health care choices available to Medicare beneficiaries, reduce the regulatory burden on the federal government, and promote the benefits of fair market competition. In addition, some analysts contend vouchers are the only feasible solution to Medicare's short-term financing problems and the long-term "crisis" of the retirement of the baby-boom generation. The author argues against these claims. Vouchers would not work as advertised by proponents because of the limitations of risk-adjustment methods and unrealistic assumptions about consumer choice. Moreover, the elderly and disabled Medicare population is ill-suited to cope in a competitive insurance system. Implementation of vouchers would therefore pose a threat to both the health of beneficiaries and the stability of the Medicare program. The implications of this analysis for Medicare reform are discussed.

Rethinking Medicare reform.

Many health policy analysts argue that demographic pressures, the inflationary nature of fee-for-service payment, and the uncontrollable nature of defined-benefit insurance make Medicare unsustainable in its current form. They assert that Medicare can remain fiscally viable in the next century only by embracing a voucher system and exposing beneficiaries to the economic consequences of their medical care decisions. We argue here, however, that Medicare need not rely on vouchers or on placing financial incentives on individual beneficiaries to control costs. Instead, we contend that Medicare can control expenditures the way most other industrial democracies do: through budgetary caps and centralized regulation of provider payments.

Managed care and Medicare reform.

A primary goal of many Medicare reform proposals is to move program beneficiaries into managed care plans operated by private insurance companies. Advocates contend that managed care plans, especially health maintenance organizations (HMOs), can save substantial money for the federal government, while also improving the quality of medical care and scope of covered benefits for Medicare enrollees. Should Medicare follow the private sector by adopting managed care-based reforms? This article summarized the claims that are made for and against incorporating managed care into Medicare, and reviews evidence from the program's experience with HMOs on financial savings, benefits coverage, and quality of care. This evidence raises concerns regarding the ability of HMOs to provide adequate care for chronically ill Medicare patients. Moreover, there is considerable uncertainty about the future performance of managed care plans. I therefore conclude that policy makers should move cautiously in embracing managed care and that Medicare should not adopt financial incentives, such as vouchers, that are intended to push beneficiaries into HMOs. However, Medicare beneficiary enrollment in managed care plans is likely to increase substantially in coming years regardless of public policy. It is therefore critical for Medicare to pursue policies that protect the quality of care for elderly and disabled patients in managed care plans; curtail excessive payments to HMOs that result from favorable selection of healthier enrollees; and preserve the current fee-for-service Medicare program.

Treatment effects of parenteral vitamins in total parenteral nutrition patients.

To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requiring total parenteral nutrition (TPN) and to assess the effect of routine parenteral vitamin therapy on vitamin levels, we studied 35 general surgical patients. Assays for 12 vitamins were performed both before and after a standard 10-day course of TPN. Patients were given nothing by mouth. The first 25 patients received a daily parenteral vitamin mixture tailored to the recommendations of the Nutrition Advisory Group of The American Medical Association (maintenance dose). The final 10 patients were given a parenteral multivitamin dose providing substantially greater amounts of most vitamins (repletion dose). Only 58% (190/324) of pre-TPN vitamin levels were normal, 25% were low, and 17% were high. No patient had fewer than two abnormal baseline levels. Vitamin levels did not correlate with serum albumin, body weight, or nitrogen balance. After 10 days of treatment, only 39% of low pre-TPN vitamin levels improved; most (45/62) of the low posttreatment levels were low at baseline. The higher repletion dose resulted in a significantly (p less than 0.01) greater percent increase in vitamin A, C, and pyridoxine levels. The prevalence of abnormal vitamin levels in this population is high (42%). Standard parenteral vitamin therapy leads to marginal improvement in abnormally low pre-TPN vitamin levels.

Total body water and total body potassium in anorexia nervosa.

In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

Estimation of fecal nitrogen in patients with liver disease.

The use of a fecal nitrogen (FN) predictive equation (Am J Clin Nutr 1978; 31:12-22, Cheng) based on dietary nitrogen intake (Nin) [FN (mg/kg/day) = 10.817 + 0.03 Nin(mg/kg/day)] was evaluated in patients with liver disease with and without concomitant lactulose therapy. Ten male cirrhotics were studied in 27 3-day nitrogen balance studies including measured daily total urinary nitrogen, total FN, and Nin calculated from weighted food records. The Cheng formula accurately predicted FN in cirrhotics not receiving lactulose who demonstrated normal digestion and absorption of dietary protein. However, the formula did not accurately reflect FN excretion in patients receiving lactulose who showed impaired protein digestibility and significantly increased fecal weight. The Cheng predictive equation is a useful index of FN excretion in patients with liver disease whose digestive and absorptive capacities are not compromised by exogenous factors.

[An interesting case]. / Der interessante Fall.

It is reported of a case of complex odontoma preventing the eruption of a molar. After surgical removal of the odontoma, the tooth erupted.