Electrophysiological study on the high K+ sensitivity of rat glomerulosa cells

 Elevation of extracellular potassium concentration by as little as some tenth of mM activates rat adrenal glomerulosa cells. In the present study some factors responsible for this high K⁺ sensitivity were examined. Using whole-cell voltage-clamp technique we found that both T-type and L-type voltage-dependent Ca²⁺ channels have very low threshold potential (–71 and –58 mV, resp.). By means of patch-clamp technique combined with single-cell fluorimetry we also provided evidence that the activation of I_gl, a K⁺-activated inward rectifying current is associated with Ca²⁺ influx. Both the low activation threshold of voltage-dependent Ca²⁺ channels and the function of I_gl contribute to the exceptional K⁺ sensitivity of the glomerulosa cells. Received: 30 September 1997 / Accepted: 4 November 1997     

Relationship between hyperglycemia and retinopathy of prematurity in very low birth weight infants

Retinopathy of prematurity (ROP) is a multifactorial vasoproliferative retinal disorder that increases in incidence with decreasing gestational age. Recently, an association between hyperglycemia and severe ROP was found in extremely low birth weight infants (ELBWI). The purpose of this study was to evaluate the possible relation between hyperglycemia and ROP at any stage in very low birth weight infants (VLBWI). We analyzed the data of 201 VLBWI. The incidence of ROP and hyperglycemia was detected and the chi2 test was applied to investigate the association between the two variables. The Clinical Risk Index for Babies (CRIB) score was attributed as a marker of illness severity. The incidence of ROP and hyperglycemia in VLBWI was 35.3 and 19.4%, respectively. ROP developed more frequently in hyperglycemic infants (p < 0.001). The gestational age, birth weight, and Apgar scores were significantly lower, the CRIB score was higher in ROP patients. In hyperglycemic ROP patients the CRIB score was significantly higher compared to euglycemic ROP patients (mean (SD) 8.1 (4.2) vs. 5.5 (3.3); p < 0.01). A logistic regression model revealed that gestational age (OR 0.59; 95% CI 0.46-0.76; p < 0.001) and hyperglycemia (OR 3.15; 95% CI 1.12-8.84; p < 0.05) are independent risk factors in ROP development. When ELBWI were analyzed separately, gestational age (OR 0.38; 95% CI 0.20-0.72; p < 0.01) and CRIB score (OR 1.58; 95% CI 1.02-2.45; p < 0.05) were found as significant contributors. Further studies are needed to elucidate the pathophysiological role of hyperglycemia in the development of vasoproliferative retinal disorder.     

Influence of thymidylate synthase gene polymorphisms on the survival of colorectal cancer patients receiving adjuvant 5-fluorouracil

The present study aimed to prospectively investigate the influence of thymidylate synthase (TS) polymorphisms (5'-TSER, 3'-TSUTR) on the disease-free survival (DFS) and overall survival (OS) of patients with colorectal cancer (CRC) who were treated with adjuvant 5-fluorouracil (5-FU) therapy. Patients were followed up for 19+/-14 months (median+/-SD). TS genotypes were determined from the peripheral blood mononuclear cells of 166 patients by polymerase chain reaction-polyacrylamide gel electrophoresis and restriction fragment length polymorphism methods. 5'-TSER 3R homozygotes showed significantly longer DFS (P = 0.048) and OS (P = 0.009). The 5'-TSER and 3'-TSUTR genotype combination groups showed a significant difference for DFS (P = 0.039) and OS (P = 0.029). Significantly better DFS (P = 0.049) and OS (P = 0.043) were observed for 6 bp/6 bp genotypes in 5'-TSER heterozygotes (n = 80). Based on this, and on hazard ratios obtained by Cox regression analysis of the DFS of genotype-combinations, the patients were classified as belonging to prognostic groups A and B. The DFS and OS of these two groups showed a highly significant difference (P = 0.002 and 0.001). In the multivariate Cox regression model, beside tumour location, the prognostic classification (groups A and B) proved to be an independent prognostic factor. Our data suggest that those TS genotypes and their combinations (group A: 3R/3R with any 3'-TSUTR genotype and 2R/3R with 6 bp/6 bp), which have been reported earlier as having high TS expression, predict significantly longer DFS and OS. We found that a combination of germline TS polymorphisms is an independent prognostic marker in selecting CRC patients with worse prognosis, and it may be worthwhile to examine whether these patients would benefit from an alternative therapy.     

Effect of tofisopam on CYP3A4 enzyme activity on human recombinant 3A4 supersome

Tofisopam is an anxiolytic agent of the BZD group, chemically 1(3-4 dimethoxyphenyl)-4methyl-5-ethyl-7,8 dimethoxy-5H-2,3-benzodiazepine. TZP differs from the traditional 1,4-benzodiazepines regarding the positions of the nitrogen atoms. Three clinical cases were reported where tofisopam increased the blood level of immunosuppressive agent leading clinically relevant adverse drug reaction and necessitating reduction of the dose of the drugs or discontinuation of the administration of tofisopam. The administered immunosuppressive agent is a substrate of the CYP3A4 system, so the effect of tofisopam on the CYP3A4 enzyme was investigated in vitro using human recombinant CYP3A4 supersome. Benzyoxy-4-(trifluoromethyl)-coumarin (BFC) was used as substrate. Tofisopam in 0.1, 0.25, 0.5, 0.75, 1 and 5 micromol/l concentrations inhibited dose dependently the enzyme activity. Activity inhibition rates were 4%, 29%, 40%, 56%, 61% and 94%, respectively and the IC50 was 0.8 micromol/l. The IC50 of positive control substance ketoconazole was 0.03 micromol/l. In in vitro experiments the inhibitory effect of tofisopam was lower than that of ketoconazole (potent CYP3A4 inhibitor) with an order of magnitude. According to the in vitro results it could be concluded that tofisopam is an inhibitor of CYP3A4 but to clarify the clinical importance of this inhibition further human clinical data are needed.     

Subnanomolar dopamine D3 receptor antagonism coupled to moderate D2 affinity results in favourable antipsychotic-like activity in rodent models: II. behavioural characterisation of RG-15

RG-15 (trans-N-{4-[2-[4-(3-cyano-5-trifluoromethyl -phenyl) –piperazine –1 -yl] -ethyl] -cyclohexyl} -3 –pyridinesulfonic amide dihydro-chloride), is a highly selective dopamine D₃/D₂ receptor antagonist with subnanomolar affinity for the D₃ receptor and nanomolar affinity for the D₂ receptor. We found that RG-15 showed a good oral bioavailability (54%) and high brain levels (approx. 900 ng/g) in rats and demonstrated antipsychotic efficacy in amphetamine-induced hyperactivity and conditioned avoidance response tests in rats, yielding ED₅₀ (median effective dose) values of 8.6 and 12 mg/kg orally, respectively. At six- to eightfold higher doses, RG-15 blocked spontaneous motor activity, while a 30 mg/kg dose of the compound caused an increase in the home-cage motility of rats. The drug did not produce catalepsy up to 160 mg/kg oral dose; moreover, it inhibited haloperidol-induced catalepsy in the range 15–60 mg/kg. RG-15 (10 mg/kg orally) restored the impaired learning performance of scopolamine- or diazepam-treated rats in a water-labyrinth paradigm. It is assumed that the motor activating, anticataleptic and cognitive-enhancing properties of RG-15 result from its potent D₃ antagonism. In this regard, RG 15 clearly differs from other antipsychotics. Olanzapine, clozapine and amisulpride all showed efficacy against amphetamine-induced hyperactivity and on conditioned avoidance, but compared to RG-15, they proved to be more cataleptogenic and depressed or did not change the home-cage activity of animals. Olanzapine was also inactive in the learning paradigm. Our results suggest that subnanomolar dopamine D₃ receptor antagonism coupled to moderate D₂ affinity may result in an antipsychotic profile characterised by a lack of extrapyramidal side effects and secondary negative symptoms with simultaneous efficacy on positive and cognitive symptoms of schizophrenia.     

Sequential design with boundaries approach in pediatric intervention research reduces sample size

ObjectiveTo estimate the difference between the number of subjects actually included in pediatric sequential trials and the sample size that would have been included with a fixed-sample design.Study Design and SettingA systematic review of pediatric sequential trials was performed. Methodological quality was assessed using a criteria list based on the CONSORT (Consolidated Standards of Reporting Trials) statement, and data were extracted by two reviewers independently. Where possible, fixed sample size calculations were performed using the same assumptions as those of the sequential design, and compared with the reported number of included patients.ResultsTwenty-four sequential trials, published between 1963 and 2005, were found. In nine studies, the information about the assumptions was sufficient to calculate a fixed sample size. The median reduction in included sample size in these trials compared with the fixed sample size calculation was 52 subjects (range: ?22 to 229), a reduction of 35% (range: ?42% to 90%) of the fixed sample size. The median sample size reduction when considering the number of subjects included in the analysis until crossing of the boundaries was 77% (range: 15–90%).ConclusionSequential design is a useful method for optimizing the sample size in pediatric clinical trials and may lead to substantial sample size reductions.     

Vaccine-driven serotype-rearrangement is seen with latency in clinical isolates: Comparison of carried and clinical pneumococcal isolates from the same time period in Hungary

Young children – the main asymptomatic carriers of pneumococcus – are often the source of pneumococcal infections. PCV13 replaced PCV7 in 2010 in Hungary and it became a mandatory vaccine in 2014. In this work we surveyed the effect of vaccination in three groups: in healthy children under 7?years; in children of the same age but infected with pneumococcus (P1); in older patients (P2) who were very likely not vaccinated.Nasal swabs were taken from 522 healthy children to screen pneumococcal carriage between March 2015 and May 2016. In the same time period, 146 clinical isolates were collected, mainly from mucosal infections. Serotypes, antibiotic susceptibility and clonality of the isolates was determined and compared.The carriage rate was 39.1%. Regarding carriage, the serotype distribution showed the total disappearance of serotypes 3 and 6A compared to former Hungarian studies. The prevalence of PCV13 serotypes was only 5.8% represented by three serotypes (19F, 19A, 9V). Of note, serotype 19A (a very resistant and invasive type) also decreased significantly. In the patient groups, PCV13 prevalence was higher: 17.5% (P1) and 32.6% (P2). Although serotype 3 was present in P1 (7.9%), the leading serotype was 23B (22.2%), a non-vaccine type (NVT). P2 showed the most diverse serotype distribution, but serotype 3 was predominant here (15.7%). Pneumococcal isolates from the patients were more resistant towards the tested antibiotics compared to those from carriers.PCV13 seems to be highly successful in reducing the prevalence of vaccine serotypes. The serotype-rearrangement can be seen also among clinical isolates, albeit somewhat later in time. Fortunately, the replacing serotypes are less invasive and less resistant, but, most worrisome, serotype 19F can be found again with increased frequency among carriage isolates and mucosal infections. Further surveillance is needed to carefully monitor such successful, antibiotic resistant “refugees”.     

Let us talk about eggs! Professional resistance to elective egg vitrification and gendered medical paternalism

In this paper, by applying a feminist bioethical perspective, we identify a new form of medical paternalism that still shapes contemporary legal policies on human egg cryopreservation performed without medical reasons. The fear of negligent, careless women who opt to delay their pregnancy for mere convenience is a widely known gender biased stereotype. Nevertheless, the opinions and judgments of medical professionals on this issue have not yet been sufficiently explored by in-depth research. In this essay, therefore, first we look at the broader bioethical, legal, and social aspects of human egg cryopreservation. In the second part of the paper we discuss a unique qualitative study conducted with professionals working at Hungarian IVF clinics. We argue, based on a bioethical analysis of the collected data, that when new reproduction technologies provide opportunities for women to widen their range of reproductive choices, the traditional forms of medical paternalism can be reinforced by gendered paternalism, as well. We identify several elements of gendered paternalism that characterized the attitudes of the IVF staff and discuss the professionals’ resistance to elective egg freezing and vitrification of eggs for the future. We conclude by suggesting directions for future policy. Although we focus on the Hungarian case in this paper, we are aware that similar attitudes can be observed in some other countries where this technology has become available and requested by women, but where they also face difficulties in their access to it.     

An ethnopharmacological survey of the traditional medicine utilized in the community of Porvenir, Bajo Paraguá Indian Reservation, Bolivia

Ethnopharmacological relevance

Porvenir is a semi-isolated Indian community in the Bajo Paraguá Indian Reservation in Bolivian Amazon, one of the two communities of people from the Guarasug’we indigenous nation now close to extinction. The aim of our study was the collection of data on the traditional medicine utilized in the community, and to identify new subjects for further investigation by comparison of the folk-medicinal use with the available scientific literature data.

Materials and methods

Field work was conducted for 5 months, which included participant observation, semi-structured interviews with 16 individuals, and the collection of voucher specimens for botanical identification. The knowledge of the inhabitants relating to medicinal plants was analysed by means of the modified method of [Gentry and Phillips, 1993a] and [Gentry and Phillips, 1993b], which assesses the frequency and the variety of use of plants. Scientific data were gathered on selected species, and the correlations of the traditional uses of the herbs with scientific evidence were assessed.

Results

The lifestyle and beliefs in Porvenir, botanical data on the plants used, the frequency and variety of medicinal use, diseases that occur and their possible treatment, and methods of plant application are discussed in detail. 145 plant species were registered with 451 recorded uses. The majority of the plants were utilized to treat gastrointestinal complaints (60 species), followed by diseases of the central nervous system, pain and fever (37 species), diseases of the genitourinary tract (35 species), dermatological disorders (34 species) and diseases of the respiratory system (32 species). One fifth of the species are also applied in traditional medicine in other areas of Bolivia or in other countries. The majority of the 145 species used in the community have not been extensively investigated from phytochemical and pharmacological aspects. There are no data in the scientific literature on one fifth of the species.

Conclusions

The medicine applied in Porvenir and the contemporary knowledge of the people interviewed concerning plants reflect the local traditions and their changes very well, clearly demonstrating the influence exerted by conventional medicine, and how the ancestral knowledge is progressively being forgotten. The present ethnopharmacological survey indicates that 24 species that are frequently and consistently used in the community of Porvenir are perspective for further research, as their chemistry and pharmacology have not been published to date.