Pt-CeO2 coating of carbon nanotubes grown on anode gas diffusion layer of the polymer electrolyte membrane fuel cell.

The growing of carbon nanotubes on a gas diffusion layer (GDL) was investigated using electron microscopy and photoelectron spectroscopy. The 30 nm thick Pt doped CeO2 layers were deposited by (rf) magnetron sputtering using a CeO2-Pt target on a carbon diffusion layer overgrown by carbon nanotubes. The anode prepared in such a way was tested in the proton exchange membrane fuel cell. Hydrogen/air fuel cell activity measurements normalized to the amount of used Pt revealed high specific power (W mg(-1) Pt). The high activity of this anode with CNT-grown is explained by high specific area of the catalyst, high conductivity of CNT-GDL junction and high activity of platinum present in cationic state Pt2,4+. Very high specific power and low cost together with physical vapor deposition of catalyst makes this anode preparation promising for micro fabrication of fuel cells to power mobile systems.

Platinum-doped CeO2 thin film catalysts prepared by magnetron sputtering.

The interaction of Pt with CeO(2) layers was investigated by using photoelectron spectroscopy. The 30 nm thick Pt doped CeO(2) layers were deposited simultaneously by rf-magnetron sputtering on a Si(001) substrate, multiwall carbon nanotubes (CNTs) supported by a carbon diffusion layer of a polymer membrane fuel cell and on CNTs grown on the silicon wafer by the CVD technique. The synchrotron radiation X-ray photoelectron spectra showed the formation of cerium oxide with completely ionized Pt(2+,4+) species, and with the Pt(2+)/Pt(4+) ratio strongly dependent on the substrate. The TEM and XRD study showed the Pt(2+)/Pt(4+) ratio is dependent on the film structure.

Elaboration and characterization of barium silicate thin films.

Room temperature depositions of barium on a thermal silicon oxide layer were performed in ultra high vacuum (UHV). In-situ X-ray photoelectron spectroscopy (XPS) analyses were carried out as well after exposure to air as after subsequent annealings. These analyses were ex-situ completed by secondary ion mass spectrometry (SIMS) profiles and transmission electron microscopy (TEM) cross-sectional images. The results showed that after air exposure, the barium went carbonated. Annealing at sufficient temperature permitted to decompose the carbonate to benefit of a barium silicate. The silicate layer was formed by interdiffusion of barium with the initial SiO2 layer.

[Analysis of the spectra of mutational damage of the 21-hydroxylase gene in patients with adreno-genital syndrome]. / Analiz spektra mutatsionnykh povrezhdenii gena 21-gidroksilazy u bol'nyh s adrenogenital'nym sindromom.

The spectrum of mutations in the steroid 21-hydroxylase gene (CYP21B) and the frequency of 11 mutations among 66 patients with different forms of congenital adrenal hyperplasia (CAH) were analyzed by means of PCR amplification. Each of the CAH forms was characterized by specific spectrum of diagnostically important mutations. The salt-losing (SL) form of the disease was most frequently associated with gene deletion (39%) and the 668-13C-G mutation in the second intron (23.5%), whereas the majority of simple virilizing (SV) CAH cases were associated with the 1172N mutation in exon 4 (22%), gene deletion (16.5%), and the 668-13C-G mutation (16.5%). Mutations in the steroid 21-hydroxylase gene were detected in 70% of the chromosomes from the patients with the SL and SV forms of CAH, and only in 1.3% of the chromosomes from the patients with the nonclassic (NC) form. A total of 78 mutant chromosomes from the NC CAH patients were examined, and only one case of a gene deletion in the heterozygous state was revealed. In the individuals examined, the V281L and P30L mutations described in the NC CAH patients from other populations were not detected. This result can be explained either by the fact that NC CAH cases in Russia are associated with other major mutations, or by difficult clinical diagnosis questionable CAH cases.

[Impulse secretion of gonadotropins in patients with various forms of amenorrhea]. / Impul'snaia sekretsiia gonadotropinov u bol'nykh s razlichnymi formami amenorei.

Circahoral variations of gonadotropin secretion were investigated in 5 healthy women in the follicular phase of the menstrual cycle, in 8 patients with normogonadotropic amenorrhea, in 6 patients with hyperprolactinemic amenorrhea, in 4 patients with hypogonadotropic amenorrhea, and in 10 patients with amenorrhea associated with body mass deficiency. The levels of LH, FSH, prolactin, estradiol and progesterone were determined by radioimmunoassay every 20 min for 4 hours. The results suggest that the blood levels of gonadotropins in different types of amenorrhea are determined mainly by an amplitude of their impulses.

[Ovarian steroid synthesis in tissue culture after administration of hormones and epidermal growth factor]. / Steroidogenez iaichnikov v kul'ture pri deistvii gormonov i epidermal'nogo faktora rosta.

The features of steroidogenesis of immature mouse ovaries in culture under the influence of follicle-stimulating hormones (FSH), human chorionic gonadotropin (hCG), epidermal growth factor (EGF) and insulin have been investigated during the period of reinitiation of meiosis in the oocytes. Secretion of progesterone is stimulated after addition of FSH, hCG and of insulin and EGF combination to the medium. EGF increases FSH-stimulated progesterone secretion and inhibits estradiol secretion. The ratios progesterone/estradiol and testosterone/estradiol increase, when EGF is added to the culture medium. It is analogous to the action of hCG. It is suggested that EGF may be an intrafollicular EGF regulator of luteinizing hormone action on the sex and somatic cells of the mammalian ovaries.

[The clinico-pharmacological characteristics of anteovin]. / Kliniko-farmakologicheskaia kharakteristika anteovina.

The clinical and laboratory studies carried out on 160 women showed a high contraceptive effect and good tolerance of anteovine. The contraceptive effect of the biphasic drug is determined by its antiovulatory action concurrent with inhibition of the basal periovulatory secretion of gonadotropins and secretion of sex hormones.

PIP: The results of evaluation of the contraceptive activity of the biphasic oral contraceptive anteovin are presented. 1 package of anteovin consists of 11 white tablets containing 0.05 mg of ethinyl estradiol and 0.05 mg of levonorgestrel and 10 pink tablets of 0.05 mg of ethinyl estradiol and 0.125 mg of levonorgestrel. Anteovin was tested according to the conventional 21-day regimen from day 5 of the cycle for 21 days, followed by 1 7-day rest period. Duration of anteovin administration ranged from 1 to 12 cycles. Anteovin was given to 160 women (aged 17 to 40 years old) who had a history of 618 pregnancies (182 ended by term delivery and 436 ended by induced abortion). During anteovin administration none of the women became pregnant. Side effects of anteovin included mild nausea during first several days in 12 women, breast tenderness in 4, and menstruation disorders in 8. The mechanism of contraceptive effect of anteovin was associated with ovulation inhibition. The changes in the basal temperature had a monophasic characteristic. Colpocytological examination showed decrease in the karyopyknotic and eosinophilic indices to 4-30%. All estrogen fractions (estrone, estradiol and estriol) in the urine showed statistically significant decrease on day 14-16 of the cycle (to 15.8 mcg/day, compared with 41.9 mcg/day in controls). The level of pregnanediol in the urine showed a decrease on day 20-23 of the cycle (0.66 mg/day, compared with 2.98 mg/day in controls). After 6 months of anteovin administration, there was a decrease in the basal and periovulation secretion of follicle-stimulating hormone, luteinizing hormone, and estradiol.

[The therapeutic effect of parlodel in the polycystic ovary syndrome]. / Lechebnyi éffekt parlodela pri sindrome polikistoznykh iaichnikov.

Parlodel (2.5-50 mg/day) has been given for 1 to 7 days to 33 patients with the polycystic ovary syndrome (POS). The ovulatory menstrual cycle returned in 10 (30%) patients and 4 of them conceived. Pretreatment cycle disturbance persisted in 6 (18%) patients. Parlodel reduced mid-follicular mean blood LH levels to values of normal women. Some decrease in blood testosterone levels occurred only in the second phase of the cycle. Estradiol test in 6 patients showed normal positive and negative feedbacks in the hypothalamic-pituitary-ovarian axis. Parlodel treatment reduced basal and estradiol stimulated pituitary gonadotropin secretion. It is suggested that parlodel may be used in ovulation induction in a proportion of POS patients.

[The reaction of the hypophysis to thyroliberin and metoclopramide in women with hyperprolactinemia]. / Reaktsiia gipofiza na tiroliberin i metoklopramid u zhenshchin s giperprolaktinemiei.

Functional tests with i.v. injection of metoclopramide (10 mg) and thyroliberin (200 micrograms) with a record of PRL and TSH levels for 120 min. were performed in 87 women of reproductive age (19 healthy nonpregnant women, 9 women in the early postnatal period, 10 patients with primary hypothyroidism, and 30 patients with PRL secreting chromophobe adenomas). Hyperprolactinemic anovulation was noted in 35 examinees. Comparison of the results of thyroliberin and metoclopramide tests in different groups of examinees was suggestive of a decrease in dopaminergic inhibition of the hypophysis in postnatal and adenomatous hyperprolactinemia. The presence and a degree of hyperprolactinemia in patients with primary hypothyroidism depends, probably, on the ratio of a stimulating effect of endogenous thyroliberin and inhibitory action of dopamine on hypophyseal lactotrophs.

[Antigens of the HLA system in different types of diabetes mellitus]. / Antigeny sistemy HLA pri razlichnykh tipakh sakharnogo diabeta.

HLA antigens (A, B, DR) of the tissues of 171 patients with different types of diabetes mellitus were investigated. Controls were 1867 healthy Leningrad residents (control I), not investigated with the GTT, and 38 pregnant women with the unchanged GTT during pregnancy (control II). Some features of the frequency of occurrence of individual antigens and their interlocular (HLA A, B) combinations in type I and type II diabetes mellitus and diabetes of pregnant women were established. The risk of diabetes mellitus, type I, development was shown to be on the increase in the presence of HLA DR4 in the phenotype and considerably on the decrease in the presence of HLA B17. The results point out to the genetic heterogeneity of different types of diabetes mellitus. The authors think it possible to use HLA typing for the diagnosis of type I diabetes mellitus.

[Hypothyroidism and hyperprolactinemia]. / Gipotireoz i giperprolaktinemiia.

Blood thyrotropic hormone, thyroxin, tri-iodothyronine, FSH, LH, estradiol and progesterone levels were examined in 14 patients with primary hypothyroidism and 11 normal women of reproductive age. All the women under study were subjected to functional tests with intravenous thyroliberin (TRH) and metoclopramide. All hypothyroid patients had anovulatory infertility. Hyperprolactinemia was detected in 8 of 14 patients. It is demonstrated that hyperprolactinemia, developing in cases of primary hypothyroidism, is associated with impaired dopaminergic inhibition of pituitary lactotropics. Substitution thyroidin therapy resulted in the recovery of the normal ovulatory cycle in all but one patient with secondary pituitary microprolactinoma, and 8 patients became pregnant. It is believed that damaged dopaminergic regulation of hypothalamic luliberin (RH) secretion is a direct cause of ovarian dysfunction associated with primary hypothyroidism.

[Effect of methergoline on impulse secretion of gonadotropins in women with hyperprolactinemic ovarian insufficiency]. / Vliianie metergolina na impu'lsnuiu sekretsiiu gonadotropinov u zhenshchin s giperprolaktinemicheskoi nedostatochnos'tiu iaichnikov.

The impact of methergoline, a serotonin antagonist, on the levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), prolactin, estradiol and progesterone was studied in the blood serum of 20 females with hyperprolactinemia-induced ovarian insufficiency who were under a ten-day course of its administration in a dose of 4-12 mg/day. Two patients were studied for gonadotrophin impulse secretion before and during methergoline treatment. It was revealed that the administration of the preparation led to a significant elevation of serum FSH and LH, estradiol and progesterone levels (up to the values characteristic of the preovulation phase) and enhancement of LH impulse secretion by the pituitary body. The possibility of dominant follicle growth and development was stated in the presence of persistent hyperprolactinemia. The authors supposed that the agent's effect was gained due to an enhanced secretion of the gonadotrophin-releasing hormone by the hypothalamus.

[The effect of metoclopramide on the hypophyseo-ovarian relations in patients with amenorrhea resulting from body mass loss]. / Vliianie metoklopramida na gipofizarno-iachnikovye vzaimootnosheniia u bol'nykh s amenoreei, sviazannoi s poterei massy tela.

The levels of FSN, LH, prolactin, estradiol, and progesterone were investigated in the blood of 26 women with hypothalamic amenorrhea (in 17 of them it resulted from body mass deficiency) before and during metoclopramide therapy (the drug was administered at a daily dose of 20 mg for 1 = 9 mos). The administration of the drug per os in 3 h resulted in a considerable rise of the blood level of prolactin in patients with body mass deficiency. Regular administration of the drug in this group normalized the anovulatory cycle in 5 women and caused pregnancy in one woman. In the authors opinion, this effect was due to a decrease in dopaminergic inhibition of the anterior pituitary lobe and the restoration of the mechanism of positive feedback between the ovaries and pituitary gland.

[Gonadotropic insufficiency in men with disorders of spermatogenesis]. / Gonadotropnaia nedostatochnost' u muzhchin s narusheniiami spermatogeneza.

The results of the investigation of 111 male patients with azoospermia, oligozoospermia and asthenoteratozoospermia revealed gonadotropic insufficiency in 28 (25.2%). The mean level of LH in the peripheral blood of the patients (4.36 +/- 0.70 IU/l) did not differ significantly from the indices in the control group (5.71 +/- 0.64 IU/l). The blood FSH level (0.86 +/- 0.13 IU/l) was significantly lower than the control one (4.48 +/- 0.44 IU/l), p less than 0.001. The level of testosterone in 14 patients was within normal. The clinical signs of hypogonadism were slightly expressed, gynecomastia and anosmia were absent. In 6 of 11 patients the response of FSH to LH-RH i. v. injection was either absent or sharply decreased. The LH response was absent in 2 patients. A conclusion has been made that disorder of spermatogenesis can be the only noticeable manifestation of isolated insufficiency of FSH secretion by the pituitary gland.

[Pregnancy and diabetes mellitus]. / Beremennost' i sakharnyi diabet.

The dynamics of the placental lactogenic hormone level, insulin requirements, and glycaemia during pregnancy was studied in diabetes I and II patients and diabetic pregnancies. Fructose amine and C-peptide levels in maternal and neonatal blood were measured in different diabetes types. The risk of diabetes I development in relation to the incidence of the HLA-system antigens was assessed. The need for a functional insulin therapy prior to and during pregnancy was substantiated.