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Biomedical subjects

A Lass

Publications and source records attributed to A Lass.

At least 19 recordsLinked to original sources
PubMed2004

Routine use of r-hFSH follitropin alfa filled-by-mass for follicular development for IVF: a large multicentre observational study in the UK.

The technical advance of recombinant biotechnology to manufacture FSH has resulted in a biochemically pure FSH preparation with high batch-to-batch consistency. The protein content of recombinant human FSH (r-hFSH) can be reliably quantified in mass units by size exclusion high performance liquid chromatography (SE-HPLC) enabling r-hFSH follitropin alfa (Gonal-F) to be filled and released in the vial on the basis of mass with dose variability of only +/-2% [filled-by-mass (FbM)]. Observational studies have merit in addressing the effectiveness of a new product in routine clinical practice. This non-interventional study assessed r-hFSH follitropin alfa FbM for the multifollicular stimulation of patients undergoing assisted reproduction. A total of 1427 patients were recruited in 21 centres in the UK and the mean age was 34.3 years (+/-4.48, range 18-48). Of those who started treatment, 1388 (97.3%) received human chorionic gonadotrophin and 1330 (93.2%) underwent oocyte retrieval. A total of 1213 (85%) patients had embryo transfer and in the majority of recorded cases, most embryos replaced were graded as 1 or 2 (74.6%). The ongoing clinical pregnancy rate was 29.2% per cycle and 34.4% per embryo transfer. The routine use of r-hFSH follitropin alfa FbM in normal clinical practice in IVF has been demonstrated to be effective, safe and well received by patients.

Adult↗
PubMed2001

Protein tyrosine nitration in cytokine-activated murine macrophages. Involvement of a peroxidase/nitrite pathway rather than peroxynitrite.

Peroxynitrite, formed in a rapid reaction of nitric oxide (NO) and superoxide anion radical (O(2)), is thought to mediate protein tyrosine nitration in various inflammatory and infectious diseases. However, a recent in vitro study indicated that peroxynitrite exhibits poor nitrating efficiency at biologically relevant steady-state concentrations (Pfeiffer, S., Schmidt, K., and Mayer, B. (2000) J. Biol. Chem. 275, 6346-6352). To investigate the molecular mechanism of protein tyrosine nitration in intact cells, murine RAW 264.7 macrophages were activated with immunological stimuli, causing inducible NO synthase expression (interferon-gamma in combination with either lipopolysaccharide or zymosan A), followed by the determination of protein-bound 3-nitrotyrosine levels and release of potential triggers of nitration (NO, O(2)*, H(2)O(2), peroxynitrite, and nitrite). Levels of 3-nitrotyrosine started to increase at 16-18 h and exhibited a maximum at 20-24 h post-stimulation. Formation of O(2) was maximal at 1-5 h and decreased to base line 5 h after stimulation. Release of NO peaked at approximately 6 and approximately 9 h after stimulation with interferon-gamma/lipopolysaccharide and interferon-gamma/zymosan A, respectively, followed by a rapid decline to base line within the next 4 h. NO formation resulted in accumulation of nitrite, which leveled off at about 50 microm 15 h post-stimulation. Significant release of peroxynitrite was detectable only upon treatment of cytokine-activated cells with phorbol 12-myristate-13-acetate, which led to a 2.2-fold increase in dihydrorhodamine oxidation without significantly increasing the levels of 3-nitrotyrosine. Tyrosine nitration was inhibited by azide and catalase and mimicked by incubation of unstimulated cells with nitrite. Together with the striking discrepancy in the time course of NO/O(2) release versus 3-nitrotyrosine formation, these results suggest that protein tyrosine nitration in activated macrophages is caused by a nitrite-dependent peroxidase reaction rather than peroxynitrite.

Animals↗
PubMed2001

How do patients choose private in vitro fertilization treatment? A customer survey in a tertiary fertility center in the United Kingdom.

OBJECTIVE: To assess the relevant factors affecting patients' decision when choosing a clinic for private, self-funded IVF treatment. DESIGN: Prospective anonymous closed questionnaires. SETTING: Single tertiary-care private IVF center. PATIENT(S): New patients attending primary consultation in a period of 7 months from September 1999 to March 2000. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Primary knowledge about the clinic, source of referral, knowledge of, availability of information pack, and familiarity with the clinic's success rates and treatment's price. The last question assessed the relative importance of each factor in the decision-making process according to the SERVQUAL model, modified version. All items were measured as perceptions on a 5-point Likert scale. 1 = not important, 3 = neutral, and 5 = very important. RESULTS(S): One hundred seventy-five patients completed the questionnaire. They were well informed and investigated the market before making their final choice. Patients collect information from many sources, including new channels such as the Internet. Up to one third of patients do not consult their doctor before treatment. By far the most relevant factor in decision making is the success rate (i.e., delivery rates) of the clinic, followed by recommendation by general practitioner (GP) or consultant (respectively, Likert scale score, 4.6; 95% confidence interval [CI], 4.5-4.7; and Likert scale score, 4.0; 95% CI, 3.9-4.2; P<.01). Other factors, such as cost of the treatment, friends and relatives' opinions, and distance from home were not relevant. CONCLUSION(S): Units that wish to thrive and increase their market share should deliver high-quality service and concentrate their efforts on excelling in performance.

Ambulatory Care Facilities↗
PubMed2001

Leukemia inhibitory factor in human reproduction.

OBJECTIVE: To describe the clinical findings, expressions, interactions, and clinical implications of leukemia inhibitory factor (LIF) in human reproduction. DESIGN: Review of published articles. SETTING: Clinical development unit of biotechnology company. INTERVENTION(S): None. RESULT(S): In the endometrium, LIF is expressed in a menstrual cycle-dependent manner, with the highest level occurring at the time of implantation. LIF is also detected in uterine flushing, and its level is significantly lower in women with unexplained infertility. Likewise, endometrial explants derived from women with unexplained infertility showed reduced levels of LIF secretion. Binding of LIF to LIF receptor and gp130 activates signal transduction pathways. LIF receptor is expressed in endometrium, oocytes, and blastocysts. Cytotrophoblasts cultured in the presence of LIF differentiate toward an anchoring extravillous phenotype. CONCLUSION(S): On the basis of reports gathered from animal and human studies, LIF appears to play an important role in implantation and in the establishment of pregnancy.

Animals↗
PubMed2001

XX males without SRY gene and with infertility.

The case of a 28 year old male with normal male phenotype, in whom repeated seminal analysis showed complete azoospermia, is presented. Peripheral blood culture for chromosome studies revealed 46 chromosomes with XX constitution. Polymerase chain reaction (PCR) analysis of genomic DNA failed to detect the presence of the sex-determining region of the Y chromosome (SRY). A literature review of all SRY-negative XX males with normal male phenotype showed that this case is the sixth reported case but the first to be diagnosed during the investigations of infertility. The frequency, aetiology and diagnosis of this rare syndrome are also reviewed.

Adult↗
PubMed2001

Assessment of ovarian reserve - is there a role for ovarian biopsy?

The pool of primordial follicles in the ovary or 'ovarian reserve' is a major factor in the human fertility potential. The ageing ovary is characterized by reduction of the number of primordial follicles and this loss accelerates in the late 30's and precedes the menopause by 10-12 years. Woman's age alone or with a combination of biochemical markers, dynamic tests and ultrasound measurements fail to predict this loss accurately. In this manuscript, a novel approach of histopathological examination of ovarian biopsy for the evaluation of infertility, especially in unexplained infertility and in women in the later part of reproductive life, is discussed.

Aging↗
PubMed2001

Protein tyrosine nitration in mouse peritoneal macrophages activated in vitro and in vivo: evidence against an essential role of peroxynitrite.

Tyrosine nitration is considered a key reaction of peroxynitrite-triggered tissue injury in inflammatory diseases. We investigated the potential involvement of peroxynitrite in protein tyrosine nitration in isolated murine peritoneal macrophages activated either in vitro with interferon-gamma/lipopolysaccharide or in vivo by priming mice with Corynebacterium parvum (10 mgxkg-1). Both protocols led to release of NO and accumulation of nitrite accompanied by formation of protein-bound 3-nitrotyrosine. Oxidation of dihydrorhodamine 123, a measure of peroxynitrite release, remained close to basal levels upon in vitro activation of the macrophages but was increased approximately twofold in vivo. Tyrosine nitration in macrophages activated in vitro was inhibited by catalase and the time course of nitration correlated with nitrite accumulation, whereas superoxide (O2*-) and H2O2 release occurred at much earlier times. To address the contribution of O2*- and peroxynitrite to in vivo nitration, a O2*- scavenger (MnTBAP; 1 mgxkg-1) was given to C. parvum-primed mice. MnTBAP led to almost complete inhibition of C. parvum-triggered O2*- and peroxynitrite release, whereas nitrite accumulation and formation of 3-nitrotyrosine were less affected ( approximately 50% of controls). These results argue against an essential role of peroxynitrite in protein tyrosine nitration in vivo.

Animals↗
PubMed2000

IVF performance of women who have fluctuating early follicular FSH levels.

OBJECTIVES: The aim was to evaluate whether women who have early follicular follicle-stimulating hormone (FSH) levels > 12 mIU/ml have reduced response to follicular stimulation for in vitro fertilization (IVF) in a following month, in spite of normal FSH levels. MATERIAL AND METHODS: In a 3-year period from January 1996 to December 1998, 303 women aged 38 years and above and/or who had previously responded poorly to superovulation for IVF gave blood samples for FSH, luteinizing hormone (LH), and estradiol (E2) on day 2 of menstruation before commencing treatment. RESULTS: In 117 (38.6%) of these women, FSH levels were > 12 mIU/ml (range 12-114 mIU/ml). Sixty-six of these women gave a further 130 blood samples for FSH measurement in the following months. Seventy-eight (60.0%) of the tests showed raised FSH value > 12 mIU/ml. Thirty women whose repeat FSH levels were < 12 mIU/ml underwent 41 IVF cycles (group 1). Sixty-three other women, older than 38 and/or who had a poor response to superovulation previously and whose FSH levels were < 12 mIU/ml, served as the control group (group II). There were no differences in the responses to superovulation and delivery rates between the two groups (14.6% vs. 12.7%). CONCLUSIONS: Women whose early follicular phase FSH levels were raised > 12 mIU/ml had an increased risk (> 50%) that in subsequent cycles levels would remain raised, and it was not possible to predict which individuals would have favorable FSH levels. If the cycle day 2 FSH level returns to a "normal" level of < 12 mIU/ml, women aged 40 and above had substantial cycle cancellation rates (43%), but patients who achieved the stage of embryo transfer had a good chance of conceiving, regardless of their age.

Adult↗
PubMed2000

Effect of coenzyme Q(10) and alpha-tocopherol content of mitochondria on the production of superoxide anion radicals.

The effects of coenzyme Q(10) (CoQ(10)) and alpha-tocopherol on the rate of mitochondrial superoxide anion radical (O2(./-)) generation were examined in skeletal muscle, liver, and kidney of 24-month-old mice. Mice were orally administered alpha-tocopherol (200 mg.kg(-1).day(-1)) alone, CoQ(10) (123 mg.kg(-1).day(-1)) alone, or the two together for 13 wk. Administration of alpha-tocopherol resulted in an approximately sevenfold elevation of mitochondrial alpha-tocopherol content. Intake of CoQ(10) alone caused an approximately fivefold increase in CoQ content (CoQ(9) and/or CoQ(10)) and alpha-tocopherol of mitochondria. The rate of (O2(./-)) generation by submitochondrial particles (SMPs) was inversely related to their alpha-tocopherol content but unrelated to CoQ content. Experimental in vitro augmentation of SMPs with varying amounts of alpha-tocopherol caused an up to approximately 50% decrease in the rate of O2(./-) generation. Similar in vitro augmentations of SMPs with CoQ(10) had previously been found to have no effect on the rate of O2(./-) generation The CoQ(10)-induced elevation of alpha-tocopherol in the present study was inferred to be due to a 'sparing/regeneration' by CoQ. Results indicate the involvement of alpha-tocopherol in the elimination of mitochondrially generated O2(./-)

Animals↗
PubMed1999

A sensitive chemiluminescence method to measure the lipoxygenase catalyzed oxygenation of complex substrates.

Oxidative modification of low-density lipoprotein (LDL) has been implicated as a patho-physiological process in early atherogenesis and 15-lipoxygenases (15-LOX) may be involved. While studying the in vitro kinetics of the 15-LOX/LDL interaction, we found that the conventional spectrophotometric assays failed in the range of substrate saturation owing to the high optical density of concentrated LDL solutions. Therefore, we developed a much more sensitive assay system which was based on peroxide induced isoluminol enhanced chemiluminescence. With this method reliable kinetic data were obtained at LDL concentrations of up to 1 mg/ml. To validate this luminometric method the kinetic parameters of 15-LOX catalyzed oxygenation of linoleic acid (Km=3.7 microM, kcat=17 s-1) were determined and we observed a good agreement with previously published data obtained with a spectrophotometric assay. Moreover, we found that the kinetic constants of 15-LOX catalyzed LDL oxidation (Km=0.64 microM, kcat=0.15 s-1) are quite different from those of free fatty acid oxygenation and that the cholesterol esters are preferentially oxidized during 15-LOX/LDL interaction. Vitamin E depletion does not reduce the rate of LDL oxidation and analysis of the structure of the oxygenation products suggests that the majority of the products were formed via direct LOX catalyzed oxidation of LDL ester lipids. The luminometric method described here is not restricted to the measurement of LOX catalyzed LDL oxidation, but may also be used to determine kinetic constants for the oxidation of other complex substrates such as biomembranes or liposomes.

Arachidonate 15-Lipoxygenase↗
PubMed1999

Mitochondrial coenzyme Q content and aging.

The main objective of this study was to determine the nature of the relationship between aging and mitochondrial coenzyme Q (CoQ) content. Mitochondria in the heart, skeletal muscle, kidney and brain of the mouse varied in both the amount of total CoQ (CoQ9 + CoQ10) content as well as in the ratio of the CoQ9 to CoQ10. CoQ content declined with age only in the skeletal muscle. Caloric restriction (CR) resulted in an increase in the amount of CoQ9 in skeletal muscle mitochondria. This effect was partially reversible upon termination of the caloric restriction regimen. Results suggest that a decrease in mitochondrial CoQ content is an integral aspect of aging in skeletal muscle.

Aging↗
PubMed1999

How useful is cervical dilatation in patients with cervical stenosis who are participating in an in vitro fertilization-embryo transfer program? The Bourn Hall experience.

OBJECTIVE: To evaluate the place of cervical dilatation performed at the initial visit in an IVF-ET cycle in patients with known cervical stenosis. DESIGN: Retrospective study. SETTING: A tertiary care assisted conception unit. PATIENT(S): Fifty-seven patients who failed to conceive after a previous ET attempt and in whom the ET was classified as "difficult." INTERVENTION(S): Cervical dilatation under general anesthesia after pituitary suppression and before gonadotropin stimulation. MAIN OUTCOME MEASURE(S): Ease of the ET procedure and clinical pregnancy rate. RESULT(S): Eighteen (31.6%) of 57 women who failed to conceive after a previous attempt at IVF-ET achieved a clinical pregnancy after cervical dilatation. In 40 patients (70.2%), the subsequent ET was classified as "easy," whereas in the other 17 (29.8%), it remained difficult. The pregnancy rate was significantly higher when the ET was easy than when it was difficult (40% versus 11.8%, P<.05). CONCLUSION(S): In patients with cervical stenosis and a previous difficult ET, cervical dilatation during the initial visit leads to an easier subsequent ET and improves the pregnancy rate.

Adult↗
PubMed1999

Effects of coenzyme Q10 and alpha-tocopherol administration on their tissue levels in the mouse: elevation of mitochondrial alpha-tocopherol by coenzyme Q10.

Coenzyme Q (CoQ) was previously demonstrated in vitro to indirectly act as an antioxidant in respiring mitochondria by regenerating alpha-tocopherol from its phenoxyl radical. The objective of this study was to determine whether CoQ has a similar sparing effect on alpha-tocopherol in vivo. Mice were administered CoQ10 (123 mg/kg/day) alone, or alpha-tocopherol (200 mg/kg/day) alone, or both, for 13 weeks, after which the amounts of CoQ10, CoQ9 and alpha-tocopherol were determined by HPLC in the serum as well as homogenates and mitochondria of liver, kidney, heart, upper hindlimb skeletal muscle and brain. Administration of CoQ10 and alpha-tocopherol, alone or together, increased the corresponding levels of CoQ10 and alpha-tocopherol in the serum. Supplementation with CoQ10 also elevated the amounts of the predominant homologue CoQ9 in the serum and the mitochondria. A notable effect of CoQ10 intake was the enhancement of alpha-tocopherol in mitochondria. alpha-Tocopherol administration resulted in an elevation of alpha-tocopherol content in the homogenates of nearly all tissues and their mitochondria. Results of this study thus indicate that relatively long-term administration of CoQ10 or alpha-tocopherol can result in an elevation of their concentrations in the tissues of the mouse. More importantly, CoQ10 intake has a sparing effect on alpha-tocopherol in mitochondria in vivo.

Animals↗
PubMed1999

Comparisons of coenzyme Q bound to mitochondrial membrane proteins among different mammalian species.

The objective of this study was to elucidate the mechanisms that govern the variations in the rates of mitochondrial superoxide anion radical (O2-*) generation in different species. The amounts of coenzyme Q (CoQ) associated with mitochondrial membrane proteins were compared in five different mammalian species, namely mouse, rat, rabbit, pig, and cow. Micelles of cardiac mitochondria were prepared using Triton X-100 or deoxycholate (DOC) as detergents, and the micelles containing mitochondrial proteins were sedimented by sucrose density ultracentrifugation. The amount of CoQ present in both types of micelles varied in different species, whereas alpha-tocopherol, another lipoidal molecule in mitochondrial membranes, could not be detected in the micelles of any of these species. The amounts of CoQ bound to mitochondrial proteins in DOC micelles were higher in those mammalian species where CoQ10 was the predominant CoQ homologue, and the amounts were found to be inversely correlated with the rate of mitochondrial 02-* generation among different species. Results also indicated that mitochondrial CoQ exists in at least two distinct pools, one of which is associated with the membrane proteins. The degree of association between CoQ and membrane proteins appears to be a factor determining the rate of mitochondrial O2-* generation.

Animals↗