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A Kivelä

Publications and source records attributed to A Kivelä.

30 records · Page 2Linked to original sources
PubMed1990

Does ephedrine influence newborn neurobehavioural responses and spectral EEG when used to prevent maternal hypotension during caesarean section?

The recovery of 16 infants born by elective caesarean section with spinal anaesthesia, in which either ephedrine or fluid load was used to prevent maternal hypotension, were studied using Scanlon's neurobehavioural tests and a computerized EEG. Neurobehavioural testing showed no differences between the ephedrine and the non-ephedrine groups of infants at ages of 3 h, 1 day, 2 days and 4-5 days, whereas the spectral EEG showed significant differences between the two groups during the first 2 h after delivery, which had disappeared 24 h later. It is suggested that small doses of ephedrine given to the mother i.v. to prevent hypotension during spinal anaesthesia have short-lived effects on the neonate's central nervous system, which will be detected in the spectral EEG, but not in neurobehavioural tests.

Adult↗
PubMed1989

Serum and amniotic fluid melatonin during human labor.

The serum and amniotic fluid concentrations of melatonin (MT) were measured by RIA during human labor in different conditions related to the type of delivery and the time of the day of delivery. Serum MT concentrations displayed a normal diurnal rhythm, resembling that of nongravid women; the mean concentration [163.8 +/- 149.6 (+/- SD) pmol/L] at night was significantly (P less than 0.001) higher than that during the day (31.4 +/- 16.3 pmol/L). The amniotic fluid MT concentration, which showed a significant positive correlation to the serum MT concentration (r = 0.625; P less than 0.01), also showed an obvious diurnal rhythm; the mean MT concentration was significantly (P less than 0.01) higher during the night [99.3 +/- 59.3 (+/- SD) pmol/L] than during the day (58.9 +/- 33.5 pmol/L). Reverse phase high pressure liquid chromatography confirmed that the amniotic fluid MT immunoreactivity eluated as synthetic MT. During the night the mean amniotic fluid MT concentration [99.3 +/- 59.3 (+/- SD) pmol/L] was significantly (P less than 0.01) lower than that in serum (178.9 +/- 189.6 pmol/L). The progress of delivery, estimated by cervical dilatation, did not affect serum MT concentrations. Induction of delivery by amniotomy and/or oxytocin, and operative delivery by cesarean section had no effect on serum MT concentrations. Human MT secretion does not seem to be influenced by the physical stress of labor or endocrine changes associated with parturition. The single factor regulating MT secretion during human delivery appears to be the time of day.

Adult↗
PubMed1988

Seasonal, menstrual and circadian secretions of melatonin, gonadotropins and prolactin in women.

In order to evaluate the role of the pineal gland in human reproduction, day- and night-time concentrations of serum melatonin, FSH, LH and prolactin were measured by radioimmunoassays on various days of the menstrual cycle during summer (average daylight 22 h) and winter (daylight 5 h) in healthy females (n = 12) from northern Finland (65 degrees N). A multifactorial analysis of variance showed that, in addition to the well-established increases of gonadotropins at midcycle and melatonin and prolactin at night, there was a significant effect of season on the serum levels of melatonin and LH. Night-time serum melatonin levels on cycle days 2 and 10 were 27% and 49% (P less than 0.05 and less than 0.01) higher in winter than in summer. Night-time serum LH levels at midcycle were 76% (P less than 0.05) higher in summer than in winter. There were no significant effects of season on the serum levels of FSH, prolactin, day-time melatonin or LH outside the mid-cycle. Neither were there any significant effects of the day of the menstrual cycle on the serum melatonin levels. It is possible that in winter the high levels of melatonin in the follicular phase have an inhibitory effect on the serum LH levels. In summer the melatonin levels are lower and perhaps less inhibitory on the secretion of LH, resulting in the stimulation of the reproductive competence in human females.

Adult↗
PubMed1987

Inverse seasonal relationship between melatonin and ovarian activity in humans in a region with a strong seasonal contrast in luminosity.

The effects of season on the activity of the pituitary-ovarian axis and the pineal gland were studied in 11 women by serum and urinary melatonin determinations and in 21 women by measurements of the serum concentrations of anterior pituitary and ovarian hormones during the dark and light seasons. A melatonin index was determined by integration of the area below the curve of serum melatonin concentrations during 24-h periods in both seasons. During the dark season, the daytime 12-h melatonin index and daytime urinary melatonin excretion were significantly higher than during the light season. In addition, the duration of the nocturnal melatonin pulse (serum melatonin levels, greater than 65 pmol/L) was lengthened during this season, whereas the mean serum estradiol concentration was significantly decreased at the time of ovulation and during the luteal phase of the cycle, indicating lowered ovarian activity. Luteal phase gonadotropin concentrations were increased during the dark season, which was also characterized by increased sex hormone-binding globulin (SHBG) and decreased free testosterone concentrations and free androgen indices (ratio of testosterone to SHBG X 700) throughout the menstrual cycle. The dark season was thus characterized by increased melatonin secretion and decreased ovarian and androgenic activities. In summary, we characterized two season-dependent hormonal phenomena. Although we did not prove any cause and effect association between melatonin and anterior pituitary-ovarian hormones, the inverse seasonal relationship in pineal gland and ovarian secretion suggests that melatonin is causally related to reproduction in humans.

Adult↗
PubMed1980

Serum progesterone, estradiol, and estriol before and during induced labor.

To investigate the association of serum levels of progesterone (P), estradiol (E2), and estriol (E3) with the initiation of regular contractions, venous blood samples were taken prior to and 3 hours after the successful induction of labor in 83 parturients by means of low amniotomy and intravenous oxytocin infusion. The serum P level and P/E2 ratio decreased and serum E2 level increased after induction in healthy primigravidas and in parturients with an initial P dominance (serum P/E2 ratio more than 5). There was also a decrease in the serum P level and P/E2 ratio in postterm patients and parturients with a ripe cervical state. Cholestasis of pregnancy was associated with a rise in the serum level of E2 and a decrease in the P/E2 ratio. In an unfavorable cervical state there was a rise in the serum E2 level; patients with an initial E2 dominance (serum P/E2 ratio 5 or less) showed a rise in the serum P level and P/E2 ratio. Healthy multigravidas and patients with pre-eclampsia did not show any hormonal changes. The onset of induced labor seems to be associated with a rise in serum E2 concentration and/or with a drop in P concentration. The increase in serum E2 level is thought to be due to the activation of the anterior pituitary--adrenal axis. The lower P level is supposedly a result of diminished uteroplacental circulation.

Cervix Uteri↗
PubMedDate not supplied

Ethnic differences in enzyme and DNA polymorphisms of human tissue-specific alkaline phosphatases.

Enzyme and DNA polymorphisms and haplotypes of tissue-specific alkaline phosphatase genes were studied in Finns, Saamis and Swedes. In placental alkaline phosphatase (PLAP) restriction fragment length polymorphisms (RFLPs), found after digestion with RsaI and PstI, no significant population differences were observed. The PstI RFLP of the germ cell alkaline phosphatase (GCAP) locus showed significant allele frequency variations between Finns and Swedes (p = 0.014) and between Saamis and Swedes (p = 1 x 10(-4)). Electrophoretic enzyme variants of PLAP were studied in Finns and Swedes. The PLAP variant 18 (D in older nomenclature) was found at a polymorphic frequency in the Finnish sample. In all populations, strong linkage disequilibria were found between the RFLPs and between RFLPs and electrophoretic PLAP types. There was, however, one notable exception: between the RsaI RFLP of PLAP and the PstI RFLP of GCAP no linkage disequilibrium was found. Two new RFLPs were observed in the Finnish population sample, a RsaI mutant site in PLAP with a frequency of 0.02 and a KpnI mutant site outside and upstream of the PLAP gene with a frequency of 0.036. In accordance with findings in previous studies at the enzyme level, PLAP also appeared to be more polymorphic than GCAP and intestinal alkaline phosphatase at the DNA level.

Alkaline Phosphatase↗
PubMedDate not supplied

Is p53 polymorphism maintained by natural selection?

We present here a new interesting feature of the human tumor suppressor gene p53: a very pronounced ethnic and clinal variation of polymorphic codon 72 alleles. The frequency of the A1 (Pro) allele showed a north-south cline from 17% in Swedish Saamis to 63% in African Blacks (Nigerians), and there was a significant (p < 0.001) correlation (r = 0.95) between the A2 frequency and latitude. In the Finnish and Swedish populations no significant differences were found with respect to the genotype and allele distributions in spontaneously aborted fetuses and liveborn children, which makes differential intrauterine selection unlikely. However, the ethnic and clinal variations suggest that the codon 72 polymorphism is balanced and maintained by natural selection.

Alleles↗
PubMedDate not supplied

p53 polymorphisms and haplotypes in different ethnic groups.

Three different p53 polymorphisms (a codon 72 BstUI RFLP, a 16-bp duplication in intron 3 and an MspI RFLP in intron 6) and haplotype combinations were studied in three northern European populations, viz. Finns, Swedes and Swedish Saamis. Significant ethnic differences were found in the codon 72 and 16-bp polymorphisms. The three polymorphisms were in strong linkage disequilibria, all of which were highly significant (p < 1 x 10(-18)), and ethnic differences with respect to linkage disequilibria were observed. Estimates of the frequencies of extended haplotypes showed that the most common ('wild-type') haplotype in the three populations was 2-1-2, viz, the codon 72 Arg allele linked to absence of the 16-bp duplication and presence of the MspI site. There were two additional common haplotypes, 1-1-2 and 1-2-1, and five rare haplotypes with a combined frequency of about 0.03. The present results indicate that extended haplotypes would be more informative in studies of population differences and associations between p53 germline mutations and cancer.

Base Sequence↗
PubMedDate not supplied

Placental and germ cell alkaline phosphatase RFLPs and haplotypes associated with spontaneous abortion.

Placental alkaline phosphatase (PLAP) and germ cell alkaline phosphatase (GCAP) are controlled by closely linked genes on chromosome 2q34-q37. In previous investigations, associations have been found between PLAP types and spontaneous abortion. In this study, PLAP and GCAP RFLPs and haplotypes were found to show highly significant associations with spontaneous abortions in the Finnish and Swedish populations. However, different associations were found in the Finnish and Swedish populations. The Finnish abortions were associated with the GCAP allele PstI(b) 2 and the Swedish abortions with the PLAP allele PstI(a) 2. A possible mechanism behind the associations may therefore be linkage disequilibria with deleterious alleles within or close to the alkaline phosphatase gene complex.

Abortion, Spontaneous↗