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M Frederiksen

Publications and source records attributed to M Frederiksen.

At least 19 recordsLinked to original sources
PubMed2001

Conspecific reproductive success affects age of recruitment in a great cormorant, Phalacrocorax carbo sinensis, colony.

Few studies have addressed the proximate factors affecting the age at which individuals of long-lived bird species are recruited into the breeding population. We use capture-recapture analysis of resightings of 16 birth cohorts of colour-ringed great cormorants, Phalacrocorax carbo sinensis, in a Danish colony to assess the evidence for two hypotheses: conspecific attraction (earlier recruitment when the colony is large) and conspecific reproductive success (earlier recruitment following years of high breeding success). For both males and females, conspecific reproductive success was the most important covariate explaining the interannual variation in age of recruitment; colony size was also important for females. These covariates explained nearly 60% of the year-to-year variation for both sexes. The age of recruitment increased for cohorts born after 1990, and this increase was correlated with a decline in breeding success in the colony; we interpret this as an indirect and delayed density-dependent effect. Females were recruited earlier than males (mean age of recruitment for cohorts born before 1990: 2.98 years versus 3.53 years); the most plausible reason for this is a skewed sex ratio in favour of males in the adult population. Recruitment of males may thus, to some extent, be constrained by the availability of females. This study provides the first evidence that conspecific reproductive success can affect the age at which individual birds start to breed.

Aging↗
PubMed1998

Management of twin pregnancies consisting of a complete hydatidiform mole and normal fetus.

OBJECTIVE: To report the clinical features, management, and outcome of twin pregnancies consisting of a complete hydatidiform mole and a coexisting normal fetus. METHODS: Between 1966 and 1997, seven women with complete hydatidiform mole and coexisting normal fetus were treated at the John I. Brewer Trophoblastic Disease Center of Northwestern University Medical School. Clinical features, including presenting symptoms, gestational dates, hCG levels, and complications, as well as route of delivery or evacuation, pregnancy outcome, genetic analysis, and need for chemotherapy were assessed. RESULTS: Four women required uterine evacuation before 20 weeks' gestation because of vaginal bleeding or medical complications, one woman required an emergency hysterotomy because of hemorrhage at 24 weeks, and two women delivered normal, viable infants at 26 and 34 weeks. The pathologic diagnosis of complete hydatidiform mole was confirmed in each case and the chromosome complement was 46,XX in all molar gestations. Four of seven women required chemotherapy for treatment of nonmetastatic gestational trophoblastic tumors, including both women who delivered viable infants and two of the five women whose pregnancies were evacuated before 24 weeks' gestation. All four patients were treated with five to seven cycles of a 5-day methotrexate regimen and achieved complete remission. CONCLUSION: Patients with a twin pregnancy consisting of a complete mole and a normal fetus are at increased risk for hemorrhage and medical complications, as well as the development of persistent gestational trophoblastic tumor.

Adult↗
PubMed1994

[Endocarditis--clinical picture of native valve infection].

In a population of 930,000 inhabitants all records of native valve infective endocarditis diagnosed in the decade 1980-89 were reviewed. One hundred and thirty-two cases were found, of whom 23 were not diagnosed until postmortem. Median prehospital duration of symptoms was 20 days (range 0-180) and median in-hospital diagnostic delay five days (range 0-54). Known cardiac disease was found in 42%, possible portal of entry in 33%, but in 36% no predisposing factors were found. During the clinical course 55% experienced cardiac failure and 17% embolic episodes. Surgery was required in 19 patients. Of 111 culture positive cases, streptococci were found in 61 and staphylococci in 45 cases. Overall mortality was 33% with a mortality of clinically diagnosed cases of 18%. Native valve endocarditis is thus associated with a significant mortality in part due to significant diagnostic delays and a large number of post-mortem diagnosed cases. Only by securing a high level of alertness towards endocarditis can we expect a reduced mortality.

Adult↗
PubMed1992

Native valve infective endocarditis in the general population: a 10-year survey of the clinical picture during the 1980s.

In a population of 930,000 inhabitants all records of native valve infective endocarditis diagnosed in the decade 1980-89 were reviewed. Using strict case definitions 132 clinically well-defined or post-mortem diagnosed cases were found. Included were cases referred to the local department of cardiology, as well as cases treated in non-specialized departments. Of 132 cases found 23 were only diagnosed post mortem. The male/female ratio was 71/61. The median prehospital duration of symptoms was 20 days (range 0-180 days) and the median in-hospital diagnostic delay was 5 days (range 0-54 days). Known cardiac disease was found in 42% of cases, a possible portal of entry was found in 33%, but in 36% there were no predisposing factors. Remarkably, only two patients had known rheumatic heart disease and none had a known dental focus. During the clinical course 55% experienced cardiac failure and 17% embolic episodes. In 19 patients surgery was required. Of 111 culture-positive cases streptococci were found in 61 and staphylococci in 45 cases. Echocardiography was performed in 95 cases with echocardiographic signs of endocarditis in 65 patients. Overall mortality was 33% with a mortality in clinically diagnosed cases of 18%. Of 14 cases needing immediate surgical intervention, two died.

Adolescent↗
PubMed1989

Circadian variation in the pharmacokinetics of verapamil.

Circadian variation in the metabolism of verapamil was investigated in 10 patients with stable angina pectoris during treatment with sustained-release verapamil 360 mg at 08.00 h or 22.0 h. No major difference in exercise parameters was found. During the evening dosage schedule a significantly greater bioavailability (AUC) and a prolonged time to peak concentration was found. During the night (24.00 h-06.00 h) the half-life of verapamil was significantly longer than during the day (16.00 h-22.00 h). These differences in pharmacokinetics may be due to reduced hepatic blood flow at night or to circadian variation in hepatic microsomal metabolism.

Angina Pectoris↗