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Biomedical subjects

I Maier

Publications and source records attributed to I Maier.

18 recordsLinked to original sources
PubMed2001

A sensitive homologous radioimmunoassay for human relaxin-2 (h-RLX-2) based on antibodies characterized by epitope mapping studies.

We present a sensitive homologous radioimmunoassay (RIA) for the quantitative determination of human relaxin (hRLX) in human serum, plasma, seminal plasma, and urine. This assay is based on a rabbit antiserum which was generated using recombinant hRLX-2 as immunogen. Using 125I-hRLX-2 as tracer and a total incubation time of 20 - 24 hours the radioimmunoassay showed linearity in a range of 60 - 4000 ng/l, a lower detection limit of 38 ng/l and a mean recovery rate of 98.5%. Intraassay variation was 4.0% (mean = 526 ng/l) and 11.9% (mean = 2368 ng/l), and interassay variation 10.7% (mean = 256 ng/l) and 13.1% (mean = 2368 ng/l). Using hRLX-2 hexapeptides on polystyrene pins, epitopes recognized by the hRLX-2 specific rabbit antiserum were determined experimentally, and compared to predicted epitopes. Both methods led to comparable results. The antiserum, recognizing different epitopes, showed no cross-reactivity with human insulin, hZn-insulin, hIGF-I, hIGF-II, human inhibin alpha-subunit, two different forms of seminal plasma inhibin like peptide, spermolaxin, ubiquitin, prolactin, LH, FSH and hCG.

Amino Acid Sequence↗
PubMed2000

Maullinia ectocarpii gen. et sp. nov. (Plasmodiophorea), an intracellular parasite in Ectocarpus siliculosus (Ectocarpales, Phaeophyceae) and other filamentous brown algae.

An obligate intracellular parasite infecting Ectocarpus spp. and other filamentous marine brown algae is described. The pathogen forms an unwalled multinucleate syncytium (plasmodium) within the host cell cytoplasm and causes hypertrophy. Cruciform nuclear divisions occur during early development. Mature plasmodia become transformed into single sporangia, filling the host cell completely, and then cleave into several hundred spores. The spores are motile with two unequal, whiplash-type flagella inserted subapically and also show amoeboid movement. Upon settlement, cysts with chitinous walls are formed. Infection of host cells is accomplished by means of an adhesorium and a stachel apparatus penetrating the host cell wall, and injection of the cyst content into the host cell cytoplasm. The parasite is characterized by features specific for the plasmodiophorids and is described as a new genus and species, Maullinia ectocarpii.

Animals↗
PubMed1999

Vascular endothelial growth factor A (VEGF-A) mRNA expression levels decrease after menopause in normal breast tissue but not in breast cancer lesions.

We hypothesized that the regulation of microvascular functions and angiogenesis in breast tissue, a well known target of ovarian steroid action, is dependent on the hormonal exposure of the breast. Relative expression levels of VEGF-A (vascular endothelial growth factor A), a putative key regulator of angiogenesis in breast cancer, were analysed in the tumour and the adjacent non-neoplastic breast tissue of 19 breast cancer patients by quantitative reverse transcriptase polymerase chain reaction. In non-neoplastic breast specimens the expression levels of all detected VEGF-A-isoforms (189, 165, 121) were significantly higher in premenopausal compared to post-menopausal women (P = 0.02) and were inversely correlated with the patient's age (P = 0.006). In contrast, in cancerous tissues menopausal status had no influence on VEGF-A-expression levels. Benign and malignant tissues exhibited a similar expression pattern of VEGF-A-isoforms relative to each other. Thus, the regulation of the vasculature in normal breast tissue, as opposed to breast cancer tissue, appears to be hormonally dependent. Endogenous and therapeutically used hormonal steroids might, therefore, cause clinically relevant changes of the angiogenic phenotype of the human breast.

Adult↗
PubMed1999

Persistent virus integration into the genome of its algal host, Ectocarpus siliculosus (Phaeophyceae).

The brown alga Ectocarpus siliculosus frequently carries an endogenous virus, E. siliculosus virus (EsV-1), the genome of which is a circular, double-stranded DNA molecule of about 320 kbp. After infection, which occurs in the unicellular spores or gametes, the virus is present latently in all somatic cells of the host. Virus multiplication is restricted to cells of the reproductive organs. It has been an open question whether the latent viral DNA occurs as a free episome or becomes integrated into the host genome. PCR studies showed that viral DNA co-migrates with high molecular mass DNA in pulsed-field gel electrophoresis, which confirms that latent viral DNA is integrated into the host genome.

DNA, Plant↗
PubMed1998

Urinary and plasma urodilatin measured by a direct RIA using a highly specific antiserum.

Urodilatin (95-126) (URO) appears to play a major physiologic role in fluid homeostasis and produces major changes when administered intravenously. Here we describe a monospecific, high-affinity antiserum against URO with no cross-reactivity (<0.01%) against the structural highly homologous atrial natriuretic peptide 99-126 (ANP-99-126), ANP analogs, and related peptides such as brain natriuretic peptide. A competitive RIA was developed, based on this antiserum. Urine samples with or without ethanol extraction and plasma samples without pretreatment were analyzed by the RIA, which had a detection limit of 10.5 ng/L, a linear measuring range between 10.5 and 1000 ng/L, and recoveries of 93-102% in urine and 90-104% in plasma. The intraassay CVs were 8.2% and 8.1% for urine samples with 269 and 669 ng/L URO; the interassay CV was 9.7% at 839 ng/L. Using this assay, we present URO data for urine from healthy volunteers receiving low and routine sodium diets and from clinical urine specimens; we also present pharmacokinetic data for URO in plasma from patients suffering from bronchial asthma and treated by URO infusion.

Animals↗
PubMed1997

Improved purification of human bone sialoprotein and development of a homologous radioimmunoassay.

Bone sialoprotein (BSP) is a phosphorylated skeletal glycoprotein. Here we describe a new procedure for the purification of BSP involving wide-pore reversed-phase HPLC, and the development of a homologous RIA for human BSP. The immunoassay showed linearity between 3 and 120 micrograms/L, a lower detection limit of 0.7 micrograms/L, and a mean recovery rate of 99.4%. Intraassay variation was 7.0% (mean = 10.9 micrograms/L) and 6.1% (mean = 38.8 micrograms/L), and interassay variation was 9.2% (mean = 11.1 micrograms/L) and 9.4% (mean = 39.0 micrograms/L). No cross-reactivity was detected with osteocalcin, osteonectin, or bone alkaline phosphatase. Preliminary clinical evaluation in healthy controls (n = 90) showed a mean serum BSP concentration on 12.1 +/- 5.0 micrograms/L (+/- SD). BSP was significantly increased in patients with Paget disease of bone, primary and secondary hyperparathyroidism, and also in subjects with renal failure without skeletal involvement. Impairment of hepatic function did not affect serum BSP concentrations.

Adult↗
PubMed1991

Carcass and tissue fat content in the pregnant rat.

The present study in rats was aimed at determining the specific day of pregnancy on which maternal body fat accumulation starts and which tissues are involved. Most of the body weight increase at day 12 of gestation corresponded to conceptus-free maternal weight which progressively increased until the 19th day of gestation after which maternal weight stabilized and the rate of conceptus weight gain became maximal. Maternal carcass fat content progressively increased until day 18 of gestation, increased very markedly on day 19, stabilized between day 19 and 20 and then decreased on day 21. These changes were the opposite of the course of the specific-gravity values. The fresh weight of lumbar fat-pads and mesenteric adipose tissue reflected the changes in carcass fat content throughout gestation. Periuterine adipose-tissue mass declined on day 12 of gestation to be recuperated later, subcutaneous adipose tissue increased on day 12 to decline progressively thereafter and interscapular brown adipose tissue remained stable until day 20 and increased on day 21. With only a few exceptions, the lipid concentration in all these adipose tissues remained stable throughout gestation. Mammary glands and liver weights increased intensely from day 12 and, whereas the lipid concentration in the former was stable, in the latter it decreased on day 12 and increased on days 18 and 19. These results show that in the rat (a) maternal carcass fat accumulation during gestation is not paralleled by the size of the different fat-storing tissues and (b) mammary-gland fat accumulation also contributes to maternal fat storage.

Adipose Tissue↗
PubMed1988

Role of lipoprotein lipase activity on lipoprotein metabolism and the fate of circulating triglycerides in pregnancy.

The mechanism that induces maternal hypertriglyceridemia in late normal pregnancy, and its physiologic significance are reviewed as a model of the effects of sex steroids on lipoprotein metabolism. In the pregnant rat, maternal carcass fat content progressively increases up to day 19 of gestation, then declines at day 21. The decline may be explained by the augmented lipolytic activity in adipose tissue that is seen in late pregnancy in the rat. This change causes maternal circulating free fatty acids and glycerol levels to rise. Although the liver is the main receptor organ for these metabolites, liver triglyceride content is reduced. Circulating triglycerides and very-low-density lipoprotein (VLDL)-triglyceride levels are highly augmented in the pregnant rat, indicating that liver-synthesized triglycerides are rapidly released into the circulation. Similar increments in circulating VLDL-triglycerides are seen in pregnant women during the third trimester of gestation. This increase is coincident with a decrease in plasma postheparin lipoprotein lipase activity, indicating a reduced removal of circulating triglycerides by maternal tissues or a redistribution in their use among the different tissues. During late gestation in the rat, tissue lipoprotein lipase activity varies in different directions; it decreases in adipose tissue, the liver, and to a smaller extent the heart, but increases in placental and mammary gland tissue. These changes play an important role in the fate of circulating triglycerides, which are diverted from uptake by adipose tissue to uptake by the mammary gland for milk synthesis, and probably by the placenta for hydrolysis and transfer of released nonesterified fatty acids to the fetus. After 24 hours of starvation, lipoprotein lipase activity in the liver greatly increases in the rat in late pregnancy; this change is not seen in virgin animals. This alteration is similar to that seen in liver triglyceride content and plasma ketone body concentration in the fasted pregnant rat. In the fasting condition during late gestation, heightened lipoprotein lipase activity is the proposed mechanism through which the liver becomes an acceptor of circulating triglycerides, allowing their use as ketogenic substrates, so that both maternal and fetal tissues may indirectly benefit from maternal hypertriglyceridemia. Changes in the magnitude and direction of lipoprotein lipase activity in different tissues during gestation actively contribute both to the development of hypertriglyceridemia and to the metabolic fate of circulating triglycerides.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1982

[Studies on the effectiveness of obstetric epidural analgesia. I. Vaginal delivery (author's transl)].

In a retrospective study 1,000 women who in 1979 had undergone a delivery either under epidural-anaesthesia or without, and instead either relation training or pethidine in small doses (20-30 mg i.v.) at the Ulm Department of Obstetrics, were followed up by questionnaire. The women of the epidural group felt that they had been adequately informed about the various possibilities of pain relief during labour, while some of the control group felt that they had been inadequately or even incorrectly informed. In the epidural group, pain relief during labour was such that 90% had hardly experienced any, or only mild discomfort, similar degree of pain relief was described by a many as 68.7% of the control group. Especially in the case of primigravida, the women of the epidural group had an insufficient urge to bear down, hence the rate of forceps delivery was relatively high, whereas this problem did not arise in the control group, where the forceps rate was markedly lower. The incidence of headache and back pain was only slightly higher in the epidural as compared to the control group, where other complaints were more frequent. 82% of the epidural group said that they would again choose this form of analgesia for future deliveries, 15% would not. In the control group 22% said that they would like an epidural for future deliveries, while 21% would not. The Apgar scoring and pH values of the newborn showed no significant differences between the groups.

Anesthesia, Epidural↗
PubMed1982

[Effectiveness of obstetric epidural analgesia. II. Caesarean section].

A questionnaire was sent to 260 women who in 1979 had undergone a caesarean section under either epidural or general anaesthesia. Those women who had an epidural for their caesarean section were on average very well informed about the procedure. In contrast, those who had been given a general anaesthetic felt that they had been badly or inadequately informed. Over 90% of the patients of both the epidural and the general anaesthetic groups described the type of anaesthesia which they had received as "very good" to "adequate". In the epidural group, 80% of the patients described the experience of the birth as very intense. Headache, back pain and other complaints such as abdominal pain and wound pain were significantly more frequent in the general anaesthetic as compared to the epidural group. 85.8% of the women given an epidural said that they would choose the same again for a future caesarean, 12.1% would not. Of the group given a general anaesthetic, 29.9% said that in the future they would choose an epidural, and 62.3% that they would prefer to have a general anaesthetic again. The Apgar score at one minute, and the umbilical artery pH values of the newborn of the epidural group were significantly better than those of the general anaesthetic group, whereas at 5 and 10 min the Apgar scores of the babies of both groups showed no differences.

Anesthesia, Epidural↗
PubMed1976

[Long-term results of fasting. Results from 132 consecutive patients after 1-6 1/2 years].

132 consecutive patients were reexamined 1-6.5 years (m = 2.8) after total fasting in hospital. 37 patients had continued to lose weight, 20 patients had maintained their fasting result (+/-2 kg) and 7 patients had slightly regained (less than 1/3 of their weight loss during fast). These 3 groups, totalling 64 patients (48%), were considered successful. Their mean overweight was diminished from 57 to 29%, corresponding to a 60% reduction of mortality in certain age groups. On the other hand, 63 patients (48%) had regained more than 1/3 of their original weight loss. Five patients (4%) were lost to follow-up. Selection of patients and long-term follow-up appeared to have a decisive bearing on long-term results of fasting, whereas factors such as age, sex, degree of overweight, onset of overweight in childhood and sports were without significant effect. From the long-term results presented, it is concluded that under certain conditions fasting in hospital is warranted. Behaviour therapy is a possible alternative in the treatment of obesity.

Adolescent↗