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Biomedical subjects

T K Jensen

Publications and source records attributed to T K Jensen.

At least 55 records · Page 3Linked to original sources
PubMed2000

Semen quality among Danish and Finnish men attempting to conceive. The Danish First Pregnancy Planner Study Team.

OBJECTIVE: To assess differences in semen quality between similar populations from Denmark and Finland. DESIGN: Comparison of semen quality between 221 Finnish men (of whom 115 had no proven fertility) and 411 Danish men with no proven fertility in two follow-up studies among normal couples trying to conceive. METHODS: In Finland male partners of couples without experienced infertility attempting to conceive were recruited through advertisements in local newspapers from 1984 to 1986. From 1992 to 1995 Danish men who lived with a partner and who had not attempted to achieve a pregnancy previously were recruited through their union when they discontinued birth control. All semen analyses were performed in accordance with the World Health Organization guidelines. RESULTS: Median sperm concentration, total sperm count and the percentage of morphologically normal spermatozoa were significantly higher among the Finnish men without proven fertility (104.0 million/ml, 304.0 million and 58% respectively) compared with the Danish men (53.0 million/ml, 140.8 million, and 41% respectively). Sperm concentration was 105.7% (95% confidence interval (CI) 58.1%-167.6%) and total sperm count was 127.4% (95% CI 71.4%-201.6%) higher among Finnish men without proven fertility than among Danish men after control for confounders. CONCLUSIONS: Some, but hardly all, of the observed difference in semen quality may be explained by differences in recruitment procedures, selection of the men and by methodological differences in semen analysis between the two countries. Also a birth cohort effect may explain some of the differences between countries as the Finnish men were recruited 11 years before the Danish men. Therefore, follow-up studies with identical recruitment and selection of men from the two countries are needed.

Adult↗
PubMed2000

Male-mediated spontaneous abortion among spouses of stainless steel welders.

OBJECTIVES: Male-mediated spontaneous abortion has never been documented for humans. The welding of stainless steel is associated with the pulmonary absorption of hexavalent chromium, which has genotoxic effects on germ cells in rodents. Clinical and early subclinical spontaneous abortions were examined among spouses of stainless-steel welders. METHODS: A cohort of first-pregnancy planners was recruited from members of the union of metal workers and 3 other trade unions. The cohort was followed for 6 menstrual cycles from the cessation of contraceptive use. Altogether, 280 pregnancies were conceived, of which 35 were detected by human chorionic gonadotrophic hormone analysis and did not survive to a clinically recognized pregnancy. Information on exposure was collected prospectively in relation to the outcome and was available for all cycles resulting in a pregnancy. Information on pregnancy outcome was collected for all 245 clinically recognized pregnancies. RESULTS: Increased risk of spontaneous abortion was found for pregnancies with exposure to paternal stainless-steel welding (adjusted relative risk 3.5, 95% confidence interval 1.3-9.1). The results were consistent in analyses of both biochemically and clinically recognized abortions. There was no increased risk for spontaneous abortion in pregnancies with paternal exposure to the welding of metals other than stainless steel. CONCLUSIONS: Male welding of stainless steel was associated with an increased risk of spontaneous abortion in spouses. A mutagenic effect of hexavalent chromium has been found previously in both somatic and germ cells, and the findings could be due to mutations in the male genome.

Abortion, Spontaneous↗
PubMed1999

[Semen quality and fertility in a population-based follow-up study].

Little is known about the importance of semen quality in male infertility. We followed 430 first pregnancy planners with no previous reproductive experience recruited among more than 50,000 cohabiting trade-union members. The couples were consecutively enrolled into the study as they discontinued contraception and were followed up for six month menstrual cycles or until a pregnancy was verified. Each man provided a semen sample at enrollment. Women kept daily record of vaginal bleeding and sexual activity. The probability of conception increased with increasing sperm concentration up to 40 x 10(6)/ml, but any higher sperm density was not associated with additional likelihood of pregnancy. The proportion of sperm with normal morphology was strongly related to likelihood of pregnancy, independently of sperm concentration. In conclusion, sperm concentration and morphology are valuable biological markers of male fecundity. Reference values for semen quality based on biological knowledge can be established.

Biomarkers↗
PubMed1999

Menstrual cycle pattern and fertility: a prospective follow-up study of pregnancy and early embryonal loss in 295 couples who were planning their first pregnancy.

OBJECTIVE: To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss. DESIGN: Prospective follow-up study. SETTING: Healthy couples recruited throughout Denmark. PATIENT(S): Two hundred ninety-five couples who were planning their first pregnancy were followed up from the discontinuation of birth control until a pregnancy was recognized within six menstrual cycles. Early embryonal losses were detected by changes in urinary hCG levels. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The probability of pregnancy occurring within one menstrual cycle (fecundity). RESULT(S): In women who had a cycle length that differed by >10 days from the usual cycle length, fecundity was approximately 25% that of women who had no variation (odds ratio 0.25, 95% confidence interval 0.09-0.68). When the combined effect of cycle variation and cycle length was assessed, cycle variation was a persistent strong predictor of fecundity. CONCLUSION(S): The mechanisms of the present findings probably are female functional disturbances in ovulation, conception, implantation, or sustained pregnancy, linked with variable menstrual cycle length. Thus, identification of medical and environmental causes of abnormal menstrual cycle patterns may provide clues to the causes of infertility. Moreover, the menstrual cycle pattern also should be taken into consideration in the clinical decision-making process.

Abortion, Spontaneous↗
PubMed1999

Distress and reduced fertility: a follow-up study of first-pregnancy planners.

OBJECTIVE: To assess the effect of psychological distress on time to first pregnancy. DESIGN: A follow-up study of time to pregnancy with prospective data on distress, with controlling for potential confounding variables. SETTING: Two university hospitals. PATIENT(S): Danish couples (n = 430) who were planning their first pregnancy and had no previous reproductive experience were followed for six menstrual cycles. Psychological distress was measured in each menstrual cycle by the General Health Questionnaire. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): A clinically recognized pregnancy or a biochemical pregnancy detected in urine samples from each period of vaginal bleeding. RESULT(S): For cycles with the highest distress score (General Health Questionnaire score >80th percentile), the probability of conception per cycle was 12.8%, compared with 16.5% in other cycles (adjusted odds ratio [OR] 0.6; 95% confidence interval [CI] 0.4-1.0). The effect of distress was found almost exclusively among women with long menstrual cycles (OR 0.1; 95% CI 0.01-0.4 and OR 0.9; 95% CI 0.5-1.4 for women with cycles of > or =35 and <35 days, respectively). An increased incidence of early embryonal loss was also found among highly distressed women with long cycles, but was based on a small number of observations. CONCLUSION(S): Psychological distress may be a risk factor for reduced fertility in women with long menstrual cycles.

Abortion, Spontaneous↗
PubMed1999

Is glycosylated haemoglobin a marker of fertility? A follow-up study of first-pregnancy planners.

We performed a follow-up study of time to pregnancy in a population of first-time pregnancy planners without previous reproductive experience. The objective of this paper is to report and discuss a finding of a strong relationship between glycosylated haemoglobin (HbA1C) and fertility. A total of 165 Danish couples without previous reproductive experience was followed from termination of birth control until pregnancy for a maximum of six menstrual cycles. HbA1C and reproductive hormones were measured at entry. Questionnaire data were collected at entry and once in each cycle during follow-up. The odds ratio (OR) for pregnancy per cycle decreased with increasing concentration of HbA1C (OR per percent HbA1C 0.4, 95% CI 0.2-0.9 for all six cycles and 0.2, 95% CI 0.1-0.5 in the first three cycles). A high concentration of HbA1C was associated with a high concentration of testosterone and a low concentration of inhibin A. No association was found between HbA1C and psychosocial distress. The reduced fertility among women with high HbA1C may be due to an association with subclinical polycystic ovaries as indicated by the hormonal profile.

Adult↗
PubMed1999

Fecundability in relation to body mass and menstrual cycle patterns.

Few studies have investigated the association between body mass index and fecundability, that is, the ability to conceive in a menstrual cycle, among fertile women with normal menstrual cycle pattern. We examined the independent and combined effects of duration and regularity of the menstrual cycle, body mass index, and fecundability from records on pregnant women attending antenatal care at Odense University Hospital, Denmark, between 1972 and 1987. We included only the first birth of each woman who had planned pregnancies and no pre-pregnancy disease (N = 10,903). We estimated the fecundability odds ratio (FR) as the odds of conception in a menstrual cycle. After adjusting for confounders, the fecundability for women with a body mass index >25 kg/m2 was lower than for women with a body mass index of 20-25 kg/m2 [FR = 0.77; 95% confidence interval (CI) = 0.70-0.84]. FR was lower for women with long (>35 days) (FR = 0.74; 95% CI = 0.63-0.87) or irregular cycles (FR = 0.78; 95% CI = 0.70-0.87), even when their body mass index was within the normal range (20-25 kg/m2) and/or their cycles were regular.

Body Mass Index↗
PubMed1999

Actinobacillus pleuropneumoniae osteomyelitis in pigs demonstrated by fluorescent in situ hybridization.

Necrotizing osteomyelitis and fibrinopurulent arthritis with isolation of Actinobacillus pleuropneumoniae serotype 2 is reported in two pigs from a herd with lameness and mild coughing problems among 8 to 12-week-old pigs. Application of fluorescent in situ hybridization targeting 16S ribosomal RNA of A. pleuropneumoniae in formalin-fixed tissue was performed to verify the association of A. pleuropneumoniae with the bone and joint lesions. By in situ hybridization A. pleuropneumoniae was demonstrated as multiple microcolonies or single cells dispersed in focal fibrinonecrotizing pleuropneumonia, in joints with arthritis, and in bone necroses including lysis of growth plate and suppurative inflammation in the adjacent trabecular metaphysis, thus demonstrating that well-known infections manifest new, unusual lesions.

Actinobacillus Infections↗
PubMed1999

Risk factors for cryptorchidism and hypospadias.

PURPOSE: We studied risk factors for cryptorchidism and hypospadias. MATERIALS AND METHODS: We performed a register based, case control study of 6,177 boys with cryptorchidism, 1,345 with hypospadias and 23,273 male controls born live in Denmark from 1983 to 1992 to determine the effects of cryptorchidism and hypospadias on the presence of the other abnormality in an individual, the presence of the abnormalities in an older brother, birth weight, weeks of gestation, maternal history of stillbirth, parity, twin birth, parental age, nationality and professional status. Unconditional logistic regression analysis was used to estimate odds ratios. RESULTS: In an individual simultaneous cryptorchidism and hypospadias were more common than expected. There was an increased risk of both entities when the same abnormality was present in an older brother. The risk of cryptorchidism and hypospadias increased with decreasing birth weight independent of weeks of gestation. Twins were at lower risk than singletons for both entities in all lower birth weight groups. An increased risk of hypospadias was noted in the sons of women who had had a previous stillbirth. The risk of cryptorchidism and hypospadias slightly increased with decreasing parity. CONCLUSIONS: Birth weight was the principal determinant of cryptorchidism and hypospadias. Twins were at lower risk for both abnormalities than singletons in the same birth weight classes. There are indications of separate genetic as well as common environmental causes of cryptorchidism and hypospadias.

Case-Control Studies↗
PubMed1999

Gross and histopathological findings in synovial membranes of pigs with experimentally induced Mycoplasma hyosynoviae arthritis.

The aim of this investigation was to describe the gross and histopathological findings in synovial membranes of pigs with experimentally induced Mycoplasma hyosynoviae arthritis and in synovial membranes of non-infected pigs of the same age. Experimental intravenous or intranasal inoculation or contact exposure with M. hyosynoviae induced arthritis in 13- to 17-week-old pigs. The acute to subacute arthritis was characterized by increased amounts of serohaemorrhagic, serofibrinous or mahogany coloured synovial fluid combined with edema and hyperaemia, followed by yellow to brownish discoloration and moderate villous proliferation of the synovial membrane. In the chronic phase moderate fibrosis was seen, but no periarticular or articular cartilage involvement. The acute to subacute histopathological characteristics were edema, hyperaemia, variable hyperplasia of synovial lining cells, increased density of subsynovial cell populations, diffuse and perivascular infiltration with lymphocytes, plasma cells and macrophage-like cells, fibrinous material, mild to moderate villous hypertrophy and mild to moderate fibrosis in chronic cases. The morphogenetic changes during the course of the infection may be described as follows: An acute preimmune phase with inflammatory changes and synovial membrane reactions dominates the first week of the infection. By the second and third week, the peak of the immune phase with masses of plasma cells and lymphocytes is seen. By 7 weeks, there is healing with moderate fibrosis. Mild ongoing reactions or recurrence of arthritis, perhaps related to persistence of mycoplasma antigens, may be seen in later phases and local antibody production may be important in this infection.

Animals↗
PubMed1998

Adult and prenatal exposures to tobacco smoke as risk indicators of fertility among 430 Danish couples.

During 1992-1995, 430 Danish couples were recruited after a nationwide mailing of a letter to 52,255 trade union members who were 20-35 years old, lived with a partner, and had no children. The couples were enrolled into the study when they discontinued birth control, and they were followed for six menstrual cycles or until a clinically recognized pregnancy. At enrollment and each month throughout the follow-up, both partners completed a questionnaire that asked them about their smoking, alcohol consumption, and intake of caffeinated beverages. The effect of current smoking and smoking exposure in utero was evaluated by using a logistic regression model with pregnancy outcome of each cycle in a Cox discrete model calculating the fecundability odds ratio. After adjustment for female body mass index and alcohol intake, diseases in female reproductive organs, semen quality, and duration of menstrual cycle, the fecundability odds ratio for smoking women exposed in utero was 0.53 (95% confidence interval (CI) 0.31-0.91) compared with unexposed nonsmokers. Fecundability odds ratio for nonsmoking women exposed in utero was 0.70 (95% CI 0.48-1.03) and that for female smokers not exposed in utero was 0.67 (95% CI 0.42-1.06). Exposure in utero was also associated with a decreased fecundability odds ratio in males (0.68, 95% CI 0.48-0.97), whereas present smoking did not reduce fecundability significantly. It seems advisable to encourage smoking cessation prior to the attempt to conceive as well as during pregnancy.

Adolescent↗
PubMed1998

Relation between semen quality and fertility: a population-based study of 430 first-pregnancy planners.

BACKGROUND: Semen analysis is part of the routine assessment of infertile couples. WHO defines a sperm concentration above 20x10(6) per mL seminal fluid as normal. We studied the association between semen quality and the probability of conception in a single menstrual cycle in Danish couples with no previous reproductive experience. METHODS: In 1992-94, we invited 52,255 trades-union members aged 20-35 years, who lived with a partner and had no children to take part in the study; 430 couples agreed. The couples discontinued use of contraception, and were followed up for six menstrual cycles or until a pregnancy was verified within this period. Each man was asked to provide a semen sample at enrolment (which was analysed without freezing). Women kept a daily record of vaginal bleeding and sexual activity. The association between semen quality and likelihood of pregnancy was assessed by logistic regression, adjusted for sexual activity and female factors associated with low fertility. RESULTS: There were 256 (59.5%) pregnancies among the 430 couples: 165 (65.0%) among those with a sperm concentration of 40x10(6)/mL or more and 84 (51.2%) among those with lower sperm concentrations. The probability of conception increased with increasing sperm concentration up to 40x10(6)/mL, but any higher sperm density was not associated with additional likelihood of pregnancy. The proportion of sperm with normal morphology was strongly related to likelihood of pregnancy independently of sperm concentration. Semen volume and motility were of limited value in pregnancy prediction. INTERPRETATION: Our study suggests that the current WHO guidelines for normal semen quality should be used with caution. Some men with sperm counts above the lower limit of the normal range defined by WHO may in fact be subfertile.

Adult↗
PubMed1998

Does moderate alcohol consumption affect fertility? Follow up study among couples planning first pregnancy.

OBJECTIVE: To examine the effect of alcohol consumption on the probability of conception. DESIGN: A follow up study over six menstrual cycles or until a clinically recognised pregnancy occurred after discontinuation of contraception. SUBJECTS: 430 Danish couples aged 20-35 years trying to conceive for the first time. MAIN OUTCOME MEASURES: Clinically recognised pregnancy. Fecundability odds ratio: odds of conception among exposed couples divided by odds among those not exposed. RESULTS: In the six cycles of follow up 64% (179) of women with a weekly alcohol intake of less than five drinks and 55% (75) of women with a higher intake conceived. After adjustment for cycle number, smoking in either partner or smoking exposure in utero, centre of enrolment, diseases in female reproductive organs, woman's body mass index, sperm concentration, and duration of menstrual cycle, the odds ratio decreased with increasing alcohol intake from 0.61 (95% confidence interval 0.40 to 0.93) among women consuming 1-5 drinks a week to 0.34 (0.22 to 0.52) among women consuming more than 10 drinks a week (P=0.03 for trend) compared with women with no alcohol intake. Among men no dose-response association was found after control for confounders including women's alcohol intake. CONCLUSION: A woman's alcohol intake is associated with decreased fecundability even among women with a weekly alcohol intake corresponding to five or fewer drinks. This finding needs further corroboration, but it seems reasonable to encourage women to avoid intake of alcohol when they are trying to become pregnant.

Adult↗
PubMed1998

Detection of Lawsonia intracellularis, Serpulina hyodysenteriae, weakly beta-haemolytic intestinal spirochaetes, Salmonella enterica, and haemolytic Escherichia coli from swine herds with and without diarrhoea among growing pigs.

A polymerase chain reaction (PCR) was optimized to detect Lawsonia intracellularis in faeces from naturally infected pigs. By combining a boiling procedure to extract DNA and a nested PCR procedure, a detection limit at 2 x 10(2) bacterial cells per gram of faeces was achieved. The optimized PCR was used together with conventional culture techniques to detect Serpulina hyodysenteriae, weakly beta-haemolytic intestinal spirochaetes (WBHIS), Salmonella enterica, and haemolytic Escherichia coli, in a case control study to examine selected risk factors for the development of diarrhoea in growing pigs. Herds with diarrhoea were selected as cases and randomly chosen herds without diarrhoea were chosen as controls. Infection with L. intracellularis significantly enhanced the chance of diarrhoea. S. hyodysenteriae, WBHIS group IV (Serpulina pilosicoli), and S. enterica were isolated only from case herds which indicate that these species may influence the development of diarrhoea. In addition, herd-type had a significant impact, that is specific pathogen-free herds showed an odds ratio at 0.2 relative to conventional herds for the development of diarrhoea.

Animals↗
PubMed1998

Specific detection of the genus Serpulina, S. hyodysenteriae and S. pilosicoliin porcine intestines by fluorescent rRNA in situ hybridization.

A fluorescent-labelledin situ hybridization method targeting rRNA was devised to facilitate specific identification and diagnosis of diarrhoea and colitis in pigs caused by the genus Serpulina, as well as to distinguish the species Serpulina hyodysenteriae and Serpulina pilosicoli in formalin-fixed colon tissue sections. A genus-specific oligonucleotide probe SER1410 targeting the five species of porcine Serpulina was thus designed. Furthermore, species specific oligonucleotide probes (Hyo1210, Pilosi209 and Pilosi1405) were also designed to detect, identify and differentiate S. hyodysenteriae and S. pilosicoli. These probes clearly demonstrated and possessed the desired specificity, when evaluated by whole cell hybridization on five reference strains and 20 isolates covering the five species of porcine Serpulina. Furthermore, the oligonucleotide probes were specific when used both, for the detection of Serpulina isolates at genus level as well as for specific detection of S. hyodysenteriae and S. pilosicoli in formalin-fixed colon tissue sections from pigs suffering from swine dysentery and porcine colonic spirochaetosis, respectively. Tissue sections were also used from pigs without any intestinal disorders as controls for estimating the specificity of the probes. The probes developed in this study thus had the potential of specific identification and histological recognition obtained in the formalin-fixed tissue samples.

Animals↗
PubMed1998

Germ cell cancer and disorders of spermatogenesis: an environmental connection?

Why is there a small peak of germ cell tumours in the postnatal period and a major peak in young age, starting at puberty? And, paradoxically, small risk in old age, although spermatogenesis is a lifelong process? Why is this type of cancer more common in individuals with maldeveloped gonads, including undescended testis, gonadal dysgenesis and androgen insensitivity syndrome? Why has there, during the past 50 years, been a quite dramatic increase in testicular cancer in many developed countries? These are just a few of many questions concerning testicular cancer. However, the recent progress in research in the early stages of testicular cancer (carcinoma in situ testis (CIS)) allows us to begin to answer some of these questions. There is more and more evidence that the CIS cell is a gonocyte with stem cell potential, which explains why an adult man can develop a non-seminoma, which is a neoplastic caricature of embryonic growth. We consider the possibility that CIS cells may loose their stem cell potential with ageing. Along these lines, a seminoma is regarded a gonocytoma where the single gonocytes have little or no stem cell potential. The Sertoli and Leydig cells, which are activated postnatally and during and after puberty, may play a crucial role for both the development of the CIS gonocyte and progression of the neoplasm to invasiveness. The reported increase in testicular cancer is not the only sign that male reproductive health is at risk. There are reports that undescended testis and hypospadias have become more common. Also semen quality has deteriorated, at least in some countries. The epidemiological evidence suggests that environmental factors may play a role. Are the environmental hormone disrupters (e.g. DDT, PCB, nonylphenol, bisphenol A) to be blamed for the apparently synchronised deterioration in these aspects of male reproductive health?

Adult↗
PubMed1998

Experimental porcine neosporosis.

Six gilts were inoculated intramuscularly with 2.5x10(6) tachyzoites of Neospora caninum on three different days of gestation to study the pathogenic effect of Neospora infection in pigs, including possible transplacental transmission. The gilts were euthanized 59, 30, and 9/10 days postinoculation (p.i.), corresponding to days 107, 102/106 and 110/111 of pregnancy. With the exception of one animal (euthanized day 9 p.i.) all gilts seroconverted as measured by the indirect, fluorescent antibody test (IFAT). Neosporosis with multifocal intralobular necrotizing hepatitis was seen in the two gilts inoculated 9/10 days before euthanasia. The uterus of one gilt inoculated 59 days before euthanasia revealed granulomatous and focal necrotizing endometritis with a corresponding multifocal necrosis of the trophoblasts of two fetuses. Transplacental neosporosis was indicated in the two fetuses by strongly elevated Neospora IFAT titres in pleural fluid and by the presence of multifocal necrotizing encephalitis and hepatitis together with non-suppurative myocarditis, pneumonitis, nephritis and hepatitis. Furthermore, N. caninum was re-isolated in cell culture from one of these fetuses. A third fetus from the same gilt revealed only disseminated, pinpoint necroses in the liver. Immunohistochemically, N. caninum tachyzoites were detected in association with histopathological changes in the liver and the endometrium of the gilts, and in the brain, liver, and allantochorion of the three fetuses.

Animals↗