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Biomedical subjects

E Dahl

Publications and source records attributed to E Dahl.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Idiopathic osteoporosis in middle-aged men--a "new" disease?].

Idiopathic osteoporosis is uncommon in middle-aged men. We discuss nine otherwise healthy men aged from 35 to 57 years, eight of whom were shown to be osteoporotic when subjected to detailed investigation because of back pain. None had suffered fractures of the appendicular skeleton as adults. All had an ordinary life style and ate a normal diet. Lumbar spine bone density was greatly reduced in all nine patients, while six of them showed normal values for cortical bone density in the forearm. Bone histomorphometry showed high turnover of bone tissue, with high bone resorption and lower than average bone formation. Serum osteocalcin levels were low in all nine patients, but alkaline phosphatase was higher than the upper normal limit in six of them. The etiology of the disease is unknown, but the pathogenesis is a result of disparity between formation and resorption of bone tissue. Unidentified environmental factors may be one of the reasons for the appearance of idiopathic osteoporosis as a "new" disease among middle-aged men.

Adult↗
PubMed1994

Chronic renal failure: diagnostic measures before parathyroidectomy.

To investigate whether conventional criteria suffice to differentiate between hyperparathyroid and aluminum (Al)-related bone disease, we obtained bone biopsies from 7 patients with chronic renal failure (CRF) at the time of PTX and 3.5-36 months later. All had hypercalcemia and elevated mid-region parathyroid hormone levels and 3 had bone pain at PTX. Bone histomorphometry revealed that 5 patients had hyperparathyroid bone disease at PTX, while 2 had osteomalacia and skeletal Al deposits. Retrospective determination of intact PTH showed normal levels at PTX in the latter two. PTX effectively reduced all indices of parathyroid hyperactivity, but the two patients with Al-related bone lesions did not improve clinically nor histologically after PTX. Intact PTH and/or bone biopsy prior to PTX could have deterred surgery in those with Al-related bone disease.

Aluminum↗
PubMed1993

Cranial base and face in mandibulofacial dysostosis.

Using longitudinal roentgencephalometry, we studied craniofacial growth in two children with mandibulofacial dysostosis. In one child, data were supplemented by three-dimensional reconstructions of CT scans and stereolithographic models of the craniofacial skeleton. Progressive basilar kyphosis was found in both children, the hypothesized caused being bending of the cranial base at the level of the sphenofrontal suture. Such bending acting in concert with abnormal growth of the mandible led to impairment of the airway. We advocate careful monitoring of craniofacial growth and respiratory function in mandibulofacial dysostosis from birth through adolescence.

Adolescent↗
PubMed1993

Surgically induced uremia in rats. I: Effect on bone strength and metabolism.

During the course of chronic renal failure (CRF) in man, renal osteodystrophy (osteitis fibrosa and/or osteomalacia) gradually develops. The present study aimed to establish a similar type of CRF leading to renal osteodystrophy in rats. During progressive CRF development over 225 days after 5/6 nephrectomy, the following serum variables were measured: creatinine, immunoreactive parathyroid hormone (iPTH), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), a25-hydroxyvitamin D3, (25(OH)D3), alkaline phosphatase, albumin, phosphate, urea nitrogen, total calcium, and other blood electrolytes. Subsequent to sacrifice, mechanical properties of the rat femur, bone histomorphometry (osteoid and eroded surfaces) and bone contents of calcium, phosphate and hydroxyproline were also examined. Serum creatinine in rats with CRF gradually escalated by some 70%, while circulating 1,25(OH)2D3 was reduced beneath detection level. Total plasma calcium and phosphate concentrations were, however, almost unchanged indicating that PTH-induced bone remodeling due to moderate hyperparathyroidism sustained calcium homeostasis. Alkaline phosphatase levels were reduced by some 50%, which reflects chronically impeded bone formation. Bone histomorphometry assessment revealed substantial elevation of resorption with moderate accompanying fibrosis in about 70% of afflicted animals. Bone calcium, phosphate and hydroxypyrroline contents remained unaltered. However, hydroxyproline/calcium ratio was marginally reduced. These results, together with altered mechanical bending stress characteristics and diminished diaphysis cross section area, confirm development of mixed bone lesions in the uremic animals. Our results are compatible with the early development of CRF in man. The established rat model is therefore useful in elucidating the precipitation and early treatment of renal osteodystrophy in humans.

Alkaline Phosphatase↗
PubMed1993

Social inequality in health--the role of the healthy worker effect.

Current occupational status is frequently used as an indicator of position in the socioeconomic structure in analyses of health inequalities. People outside the work-force are thereby ignored. One may hypothesize that due to a 'healthy worker effect' economically active people are a positively selected health group and that health-related exits from the labour marked are concentrated among low socioeconomic groups. One may therefore expect that this system of classification will show artificially small differences in health between socioeconomic groups. Analyses of material from a nation-wide representative survey and a complete set of mortality statistics confirm these expectations. When previously employed are included among currently employed, the differentials in health between the extreme groups in the occupational hierarchy widen. The system of classification has only a moderate impact on the main conclusion regarding men. For women, however, the conclusion depends more heavily on how they are classified. If one relies only on current occupation, small or inconsistent patterns emerge. Inclusion of previously employed has the effect of showing that low status women suffer from poorer health than high status women. This applies to several measures of health, i.e. morbidity, restricted activity and mortality.

Adult↗
PubMed1993

High mortality in lower salaried Norwegian men: the healthy worker effect?

STUDY OBJECTIVE: This study aimed to examine whether the high mortality in lower salaried men in Norway was related to an inflow into this group of unskilled workers with high mortality. DESIGN: Individual information on occupation was derived from the 1970 and the 1980 censuses and linked to mortality data for the period 1980-5 by the official, individual identification numbers. PARTICIPANTS: The study population included Norwegian men aged 20-64 years in 1980. All men enumerated in the 1980 census (and who were registered in the 1970 census) within the two occupational groups, unskilled workers and lower salaried employees, were included. MEASUREMENTS AND MAIN RESULTS: The subjects were allocated to the two occupational groups according to the official Norwegian classification of socioeconomic status. Mortality was measured by standardised mortality ratios (SMR). The findings suggest that a fairly large number of unskilled workers with high mortality move into the lower salaried employee group. This transition produces a higher SMR in lower salaried employees and, simultaneously, an artificially but modestly lower SMR in unskilled workers. The difference in SMR between the two groups is thereby exaggerated by 44%. The difference among the elderly was smaller. CONCLUSION: Occupational mobility consistent with "the healthy worker effect" increases the SMR of lower salaried men and, at the same time, reduces slightly the SMR of unskilled workers.

Adult↗
PubMed1993

A six-center international study of treatment outcome in patients with clefts of the lip and palate: evaluation of maxillary asymmetry.

This investigation was carried out by the European Cleft Lip and Palate Research Group. The purpose of this part of the investigation was to compare and evaluate maxillary asymmetry in children born with complete unilateral cleft lip and palate treated at cleft palate centers with different surgical management. Posteroanterior radiographs from three of the six participating centers were included in the investigation. Statistically significant differences were found in the symmetry of the anterior part of the maxillary complex. Children with a primary bonegrafting procedure involved in their primary treatment procedure had a more symmetric dentoalveolar development. Children from centers with primary surgical procedures including a vomer plasty and no involvement of the alveolar process had a more asymmetric development with a tilted premaxilla and a deviating inclination of the central incisors.

Analysis of Variance↗
PubMed1993

Spheno-occipital synchondrosis in three-month-old children with clefts of the lip and palate: a radiographic study.

The literature has been focused on differences in craniofacial form and dimension in cleft lip and palate patients. No attention has been given to possible alterations in the spheno-occipital synchondrosis although the synchondrosis is regarded as an important maturity and growth center. The purpose of the present investigation was to examine if the spheno-occipital synchondrosis in children born with major complete clefts differs on lateral radiographs from that of children born with minor incomplete clefts. Fifty-seven three-month-old children with complete clefts of the lip, alveolus and palate and 42 three-month-old children with minor incomplete clefts of the lip were included in the study. The results of the comparison showed that children with complete major clefts had a broader spheno-occipital synchondrosis compared to children with a minor incomplete cleft of the lip, and that the distance from the superior part of the synchondrosis to the sella point was shorter in children with complete clefts. These findings could be related to a defect or a delay in maturity in the early development of the cartilaginous cranial base in children with major clefts.

Alveolar Process↗
PubMed1993

A multicentre comparison of treatment regimens for unilateral cleft lip and palate using a multiple regression model.

The European Cleft Lip and Palate Research Group consists of specialists in orthodontics from six centres for the treatment of cleft palate in northern Europe. The purpose of this part of the multicentre study was to investigate whether differences in outcomes could be explained by specific treatment regimens. Three regimens that were assumed to influence the outcome of treatment were selected: Presurgical orthopaedics, closure of the palate, and primary bone grafting. The sample comprised 151 children with complete unilateral cleft lip and palate from the six centres. The result of multiple regression analysis showed that within that sample it was not possible to reach definite conclusions as to which factors exerted the most favourable influence on facial growth, but primary bone grafting was associated with reduced maxillary inclination and presurgical orthopedics with increased mandibular inclination.

Bone Transplantation↗
PubMed1993

PTH-stimulated adenylate cyclase activity and bone histomorphometry in iliac crest biopsies in the evaluation of uremic patients: a pilot study with the use of artificial intelligence.

Iliac crest biopsies of normals, uremic patients and subjects with primary hyperparathyroidism (pHPT) were investigated. It appeared that serum 1,25- and 24,25-(OH)2-D3 correlated inversely with basal adenylate cyclase (AC) activity and relative PTH-stimulated AC, respectively. Net PTH-elicited AC (dPTH-AC) activation hence reflected individual vitamin D status. The combination variable serum PTH (s-PTH) x dPTH-AC x [H+] correlated well with resorption surface (RS) in both normals, patients with pHPT or subjects with uremia, while s-PTH, dPTH-AC activity or pH as single variables were only marginally related to RS. For all subjects analyzed, osteoid volume (OV) correlated positively with serum alkaline phosphatase but negatively with serum 1,25-(OH)2-D3. OV showed no correlation with dPTH-AC, while the relationship between OV and s-PTH was strong, suggesting that PTH stimulates osteoid deposition via some signalling pathway other than cAMP. In normals, OV was inversely proportional to s-PTH, due to homologous desensitization of this signalling system. Furthermore, s-PTH was negatively correlated with urine cAMP due to homologous desensitization of the effect of PTH on the kidney 25-(OH)-D3 1 alpha-hydroxylase. This phenomenon was absent in uremic patients. Evaluation of variables by artificial intelligence showed that the prototype uremic patient exhibited serum creatinine > 900 microM, RS > 0.12, pH between 7.15 and 7.34 and s-PTH x dPTH-AC x [H+] between 0.5 and 3.7 units with the distinguishability index 'very good' (< 5% overlap) towards normals. Average similarity of uremic patients with the prototype for normal subjects was only 22%. Cluster analysis of all the variables was conducted for comparison and yielded less clinically relevant information. Hence, emulation done by the expert system was superior and clearly indicates that present treatment modalities restore normal bone turnover only to a minor degree or not at all.

Adenylyl Cyclases↗
PubMed1993

Clinical experience with HIV-infected patients at the University of Oklahoma Health Sciences Center: an update.

We reviewed the course of 545 human immunodeficiency virus (HIV)-infected patients seen between 1983 and March 30, 1991. A majority were Caucasian homosexual or bisexual men, while parenteral drug abusers represented a smaller proportion than seen nationwide. In the 274 patients with the acquired immunodeficiency syndrome (AIDS), the distribution of AIDS-defining conditions was generally consistent with those reported in studies from elsewhere in the United States. However, toxoplasmosis remained relatively uncommon. There was a slightly higher incidence of disseminated histoplasmosis compared to other studies. HIV encephalopathy (AIDS dementia) was likely underdiagnosed. Although data suggested prolongation of the asymptomatic phase of HIV infection, median survival after AIDS diagnosis remained approximately 12 months.

AIDS-Related Opportunistic Infections↗
PubMed1992

Two gap junction genes, connexin 31.1 and 30.3, are closely linked on mouse chromosome 4 and preferentially expressed in skin.

Two new gap junction genes isolated from the mouse genome code for connexin homologues of 271 and 266 amino acids, designated here Cx31.1 and Cx30.3, respectively. The two open reading frames, oriented in the same direction, are only 3.4 kb apart on mouse chromosome 4. Within the connexin family, these two proteins are most closely related to one another (70% amino acid sequence identity) and to Cx31 (65 and 68% identity, respectively). Comparison of the Cx31.1 mouse gene with a Cx31.1 cDNA showed a similar genomic organization to that found with other members of the connexin gene family, i.e. the coding and 3'-untranslated regions are contained within a single exon, which is preceded by an intron, less than 25 bases upstream of the ATG start codon. Northern blot hybridization revealed highly tissue-specific coexpression of the 1.6-kb Cx31.1 mRNA and two Cx30.3 transcripts of 1.9- and 3.2-kb size, predominantly in skin and two related mouse keratinocyte cell lines. Minor levels of Cx31.1 mRNA were detected in testis. Microinjection of Cx30.3, but not Cx31.1 cRNA, into Xenopus oocyte pairs induced formation of functional gap junction channels with unique voltage-gated parameters compared to other connexins expressed similarly.

Amino Acid Sequence↗
PubMed1992

Basal cell carcinoma. An epidemiologic study in a defined population.

BACKGROUND: The incidence of basal cell carcinoma (BCC) in a defined population is unknown. METHODS: The incidence of histologically diagnosed cases of BCC in a defined population of a city in southern Sweden was studied. Four 2-year periods were examined from 1970 to 1986. Cases from 1970 and 1980 were reexamined microscopically. RESULTS: From 1970 to 1986, the age-standardized incidence of BCC was doubled. BCC was equally common in male and female patients. It was possible to trace another BCC in the medical history of 41% of the patients. The risk of development of BCC increased rapidly with age greater than 55 years. Approximately two-thirds of the tumors were found in the head and neck region. There was a possible increase in superficial multicentric tumors on the trunk but otherwise an essentially unchanged pattern in type and distribution. CONCLUSIONS: The age-standardized incidence of histologically diagnosed BCC was doubled from 1970 to 1986. The rapid increase should be taken into consideration when planning allocation of medical resources.

Adult↗
PubMed1992

Early kidney transplantation may prevent aluminium-related bone disease.

In uraemia patients aluminium (Al) accumulation in bone leads to low turn-over bone disease. Al-related bone disease causes bone pain, non-traumatic fractures and hypercalcaemia, and does not respond to treatment with vitamin D compounds. Al-contaminated dialysate and ingestion of Al-containing phosphate binding agents are the main risk factors for bone Al accumulation. Studies of selected patients have indicated that Al-related bone disease ameliorates after successful kidney transplantation, but systematic studies of bone Al have not been reported. In a prospective study we investigated the effect of successful kidney transplantation on bone Al and clinical bone disease.

Adrenal Cortex Hormones↗
PubMed1992

Chromosomal assignments of mouse connexin genes, coding for gap junctional proteins, by somatic cell hybridization.

The connexin genes Cx31 and Cx45 coding for proteins of gap junctional subunits have been assigned to mouse chromosomes 4 and 11 by Southern blot hybridization of specific gene probes to DNA from mouse x Chinese hamster somatic cell hybrids. In addition, our results confirm the recent assignment of mouse connexin genes Cx26, Cx32, Cx37, Cx40, Cx43, and Cx46 to mouse chromosomes 14, X, 4, 3, 10, and 14, respectively, by analysis of interspecific backcrosses and by somatic cell hybridization. Our assignment of the Cx31 gene to mouse chromosome 4 locates the fourth connexin gene on this mouse chromosome to which the genes for Cx31.1, Cx37, and Cx30.3 have previously been assigned. Interestingly three of them (coding for Cx31, Cx31.1, and Cx30.3) are preferentially expressed in skin. Possibly some of the connexin genes clustered on mouse chromosome 4 may be regulated coordinately.

Animals↗
PubMed1992

Molecular cloning and functional expression of mouse connexin40, a second gap junction gene preferentially expressed in lung.

From a mouse genomic library, a clone has been isolated that codes for a connexin-homologous sequence of 358 amino acids. Because of its theoretical molecular mass of 40.418 kD it is named connexin40 (Cx40). Based on both protein and nucleotide sequence, mouse Cx40 is more closely related to mouse Cx43 (alpha subgroup of connexins) than to mouse Cx32 (beta subgroup). The highest overall homology detected, however, was to chick Cx42 (67% amino acid and 86% nucleotide identity), raising the possibility that Cx40 may be the mouse analogue. The coding region of Cx40 is uninterrupted by introns and is detected as a single copy gene in the mouse genome. High stringency hybridization of Northern blots with the coding sequence of Cx40 identified a single transcript of 3.5 kb that is at least 16-fold more abundant in lung-similar to mouse Cx37-than in other adult tissues (kidney, heart, and skin). In embryonic kidney, skin, and liver the level of the Cx40 transcript is two- to fourfold higher than in the corresponding adult tissues. Microinjection of Cx40 cRNA into Xenopus oocytes induced functional cell-to-cell channels between pairs. These channels show a symmetrical and markedly cooperative closure in response to transjunctional voltage (Boltzmann parameters of Vo = +/- 35 mV; A = 0.32) which is also fast relative to other connexin channels recorded similarly (tau = 580 ms at Vj of +/- 50 mV). Although Cx40-expressing oocytes did not couple efficiently with oocytes expressing endogenous connexins, they did couple well to Cx37-expressing oocytes. The heterotypic channels which formed had voltage-gating properties modified from those of the original homotypic forms. Transfection of mouse Cx40 DNA, under control of the SV-40 early promoter, into coupling-deficient human HeLa or SK-Hep-1 cells resulted in expression of the expected transcript and restoration of fluorescent dye transfer in transfected clones.

Amino Acid Sequence↗
PubMed1992

Aluminum metabolism and bone histology after kidney transplantation: a one-year follow-up study.

Parathyroid activity, bone aluminum (Al) metabolism, bone histology, and clinical bone disease were studied in 55 successfully grafted kidney recipients at transplantation (Tx) and after 1 yr of immunosuppression with a low dose corticosteroid and a high dose cyclosporin-A regimen. Symptoms of Al-related bone disease disappeared after Tx. Serum Al and stainable bone Al decreased. The rate of Al removal from the bone surfaces was independent of graft function (creatinine range, 62-415 mumol/L) and bone turnover. Osteoblast activity and bone formation rate increased, while mineralization lag time normalized. Indices of bone resorption remained elevated, indicating persisting hyperparathyroidism. Eighteen percent of the recipients had posttransplant hypercalcemia, most likely caused by incomplete involution of hyperplastic parathyroid glands, while 53% had normocalcemic hyperparathyroidism related to impaired graft function. Cortical thickness decreased, while cancellous bone volume remained stable after Tx; both indices correlated significantly at follow-up with their respective values at Tx. None of 46 radiologically examined recipients had aseptic bone necrosis 1 yr after Tx.

Adolescent↗