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K Christensen

Publications and source records attributed to K Christensen.

At least 145 records · Page 8Linked to original sources
PubMed1994

Etiological subgroups in non-syndromic isolated cleft palate. A genetic-epidemiological study of 52 Danish birth cohorts.

Isolated cleft palate (CP) is considered to be a heterogeneous trait with an important genetic contribution to the etiology. Multifactorial-threshold models of non-syndromic CP inheritance assume a female predominance. The present study of 52 Danish birth cohorts, using several ascertainment sources, identified 2301 CP cases. It was found that, although females tended to be more severely affected than males, the overall sex ratio was close to one. For the latter half of the study period (1962-87), which probably had the best ascertainment, the sex ratio for non-syndromic CP was 0.95 (95% C.I. 0.85-1.07). Marked difference in sex ratios for non-syndromic overt CP including the hard palate (CPH) and non-syndromic overt CP of the soft palate only (CPS) (0.69 vs 1.00, p < 1.00, p < 0.05) suggested that these two conditions may be etiologically distinct, a hypothesis which is embryologically plausible. In agreement with this hypothesis, Danish family data from surgically treated CP cases showed a strong tendency to segregate only one of the CP subtypes within families. Future studies are recommended to test the existence of a possible etiological difference between CPH and CPS.

Child↗
PubMed1993

Cleft lip (+/- cleft palate) in Danish twins, 1970-1990.

A classical twin study is one of the best methods to address the open question of the role of genes and environment in the cause of cleft lip with or without cleft palate [CL(P)]. In addition, when twin concordance rates are combined with information about the risk for CL(P) to more remote relatives, they can help to establish the most likely mode of inheritance for CL(P). The present study was based on three nation wide ascertainment sources of CL(P) in twins in Denmark during the period 1970-1990. The Danish surgical files were found suitable for ascertaining twins with non-syndromic CL(P) and a total of 39 pairs was identified through these files. In more than 70% of the cases, the zygosity assignment was based on unlike-sex or an extensive panel of blood, serum, and enzyme types. More mono- and dizygotic twin (CL(P) cases than expected were found, although the difference was not significant. The proband concordance rate for CL(P) was 60% in monozygotic twins and 10% in dizygotic twins; six cases were of unknown zygosity. This finding indicates that genetic factors play a major role in the cause of CL(P) but environmental and/or stochastic factors are probably acting too. When the familial recurrence patterns analyzed by Mitchell and Risch [1992: Am J Hum Genet 51:323-332] are interpreted in light of these new estimates of monozygotic concordance, they provide further evidence for the finding that no single locus can account for more than a six-fold increase in risk to first-degree relatives.

Cleft Lip↗
PubMed1993

[Antiphospholipid antibodies and occlusive vascular disease].

The antiphospholipid syndrome is characterized by venous and/or arterial thrombosis, recurrent foetal loss, thrombocytopenia and the presence of antiphospholipid antibodies. This study presents three case reports, which emphasize the multiform clinical features of the syndrome: one case of uncomplicated myocardial infarction in childhood and two prolonged, clinically elusive case histories, both with fatal outcome due to acute, multifocal, non-inflammatory vascular occlusion. It is important to distinguish between this syndrome and various vasculitis syndromes, although consensus on therapy for the antiphospholipid syndrome has not yet been achieved.

Adolescent↗
PubMed1993

Characterization of 24 porcine (dA-dC)n-(dT-dG)n microsatellites: genotyping of unrelated animals from four breeds and linkage studies.

Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P < 0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.

Alleles↗
PubMed1993

Marginal tissue response adjacent to Astra Dental Implants supporting overdentures in the mandible.

The aim of this study was to evaluate the marginal tissue response adjacent to implant supported overdentures. Twenty edentulous patients had 2 Astra Dental Implants placed in the canine region of the lower jaw. New overdentures were retained by individual ball attachments in 11 patients and by a bar attachment in 9 patients. Periodontal registrations were recorded 0 months, 6 months, 12 months and 24 months after the overdentures were inserted. One of the 40 fixtures was lost at the stage of abutment connection. No fixtures were lost during the 2- to 4-year observation period and no fixtures showed any periodontal signs of failure. At the 2-year examination, no pocket depths adjacent to the implants exceeded 4 mm and no bone loss exceeded 3 mm. The mean annual bone loss was less than 0.2 mm during the first 2 years. The preliminary results from this limited study were promising and showed that two osseointegrated Astra Dental Implants could successfully retain an overdenture in the lower jaw. However, long-term observation is needed for a definitive evaluation of this treatment concept.

Aged↗
PubMed1993

Trisomy 22 in a calf.

A case of trisomy 22 in a newborn calf is described. Previously, this anomaly has only been identified in one calf. The calf had several defects including brachygnathia superior, malformation of septum nasi and conchae, and an interventricular septal defect. Chromosome analysis was performed on cultured blood lymphocytes, and in all counted metaphases 61 chromosomes were present. The extra chromosome was identified as a chromosome 22 by R-banding.

Abnormalities, Multiple↗
PubMed1993

Isolated cleft palate in Danish multiple births, 1970-1990.

The etiology of most cases of isolated cleft palate (CP) is unknown. The relative importance of genes and environment can be studied using the classical twin method but only few and potentially highly selected CP twin data are available. The present CP twin study was based on four Danish nationwide ascertainment sources of CP multiple births in the period 1970-1990. The ascertainment sources covered the time period from 15 completed weeks of pregnancy to adolescence for the older cohorts. A total of 18 CP cases in multiple births were identified; two monozygotic twin pairs of which one was concordant and eight were dizygotic, discordant twin pairs. Three cases were from two triplet sets, and four discordant twin pairs were of unknown zygosity. The twin concordance rates suggest that genetic factors play a major role in the etiology of CP, but environmental and/or stochastic factors are probably acting as well.

Adolescent↗
PubMed1993

Glenoid labral tears: prospective evaluation with MRI imaging, MR arthrography, and CT arthrography.

OBJECTIVE: We prospectively compared MR imaging, MR arthrography, and CT arthrography to determine the sensitivity of each technique in detecting glenoid labral tears and in determining whether the labrum is detached or degenerated. SUBJECTS AND METHODS: Thirty patients 19-39 years old (mean, 27 years old) who had either signs and symptoms of shoulder instability or shoulder pain of unexplained origin were referred for diagnostic imaging. Each patient underwent MR imaging, followed by MR arthrography after intraarticular injection of 25 ml of a dilute solution of gadopentetate dimeglumine. Twenty-eight of thirty patients underwent CT arthrography after intraarticular injection of air and radiographic contrast material. Each patient also underwent arthroscopy or open surgery. RESULTS: At surgery, labral tears were found in 28 patients; a detached fragment was found in 26 patients. The labrum was found to be degenerated in 18. A labral tear was detected on MR images in 26 (93%) of 28, on MR arthrograms in 27 (96%) of 28, and on CT arthrograms in 19 (73%) of 26. A detached labral fragment was detected on MR images in 12 (46%) of 26, on MR arthrograms in 25 (96%) of 26, and on CT arthrograms in 13 (52%) of 25. Labral degeneration was detected on MR images in two (11%) of 18, on MR arthrograms in 10 (56%) of 18, and on CT arthrograms in four (24%) of 17. MR arthrography was the best of the three imaging techniques for showing the inferior part of the glenoid labrum and inferior glenohumeral ligament. CONCLUSION: MR arthrography and MR imaging both showed labral tears with greater sensitivity than CT arthrography did. MR arthrography was the most sensitive of the three techniques for detecting a detached labral fragment and labral degeneration. Furthermore, MR arthrography afforded the best visualization of the inferior part of the labrum and the inferior glenohumeral ligament. MR imaging and MR arthrography also enabled direct visualization of rotator cuff disease and other unsuspected associated abnormalities.

Adult↗
PubMed1993

Calcification of intervertebral discs in the dachshund: an estimation of heritability.

The heritability of calcified intervertebral discs in the dachshund was estimated using data gathered from a radiographic study. Radiographs of the vertebral columns of 274 clinically normal, 12 to 18 months old dachshunds, were examined. The dogs were offspring from 75 different sires, representing the same number of half sib groups. There were 2 to 14 offspring in each half-sib group. The number of full sib groups was 81. Calcified intervertebral discs were identified in 20.4% of the dogs. An analysis of variance that used the data as a continuous and as an either/or-variable estimated the heritability of calcified discs to be 0.22 and 0.15 respectively. A genetic factor was found to be essential for the occurrence of calcified discs in a dog while a common environmental factor presumably resulting from non-genetic causes was significant in determining the number of discs to undergo calcification in affected dogs.

Animals↗
PubMed1993

Abortion and calf mortality in Danish cattle herds.

The aetiology of abortions and calf mortality in 65 Danish cattle herds consisting of both dairy and beef breeds during a 1-year period is described. All observed aborted foetuses, still-born calves, and calves dying before 6 months of age were necropsied, and relevant microbiological examinations were performed. A total of 240 calves and 66 abortions were submitted corresponding to a calf mortality rate of 7%. The abortion frequency could not be calculated. 43% of the calves died at day 0, while 22% were aborted, 15% died during the first week of life, 9% died from 1 to 4 weeks of age, and 11% died at the age of 1 to 6 months. The most common cause was neonatal pulmonic atelectasis (stillbirth) followed by foetal infections, pneumonia, and septicaemia.

Abortion, Veterinary↗
PubMed1993

Investigations on the occurrence of hereditary diseases in the Danish cattle population 1989-1991.

The methods of the Danish Bovine Genetic Disease Programme are outlined, and the results obtained during the first 3 years in function are described. The most common disease reported was spinal muscular atrophy in calves of the Red Danish Dairy breed with 312 reports. Necropsy was performed on 162 cases, and spinal muscular atrophy was diagnosed in 82 of these. Bovine progressive degenerative myeloencephalopathy, rectovaginal constriction, syndrome of arthrogryposis and palatoschisis, hereditary chondrodysplasia (2 different types), syndactylism, epitheliogenesis imperfecta, and osteogenesis imperfecta was diagnosed with 1 case each. Lethal trait A46 was diagnosed in 4 calves. Some of these diseases have not previously been described in Denmark, and epitheliogenesis imperfecta was for the first time diagnosed in the Hereford breed. Chromosome translocation 1/29 was detected in the Blonde d'Aquitaine (BAQ), Limousine, and Red Danish Dairy breed. The aberration occurred frequently in BAQ. Furthermore, a complex chromosome translocation t(1;8;9)(q45;q13;q26) was detected in the Red Danish Dairy breed.

Abnormalities, Multiple↗