Biomedical subjects

C H Jensen

Publications and source records attributed to C H Jensen.

At least 19 recordsLinked to original sources

PubMed2001

Neurons in the monoaminergic nuclei of the rat and human central nervous system express FA1/dlk.

The gene DLK1 encodes a member of the epidermal growth factor (EGF) superfamily, delta-like (dlk). When exposed in vivo to the action of an unknown protease, this type 1 membrane protein generates a soluble peptide referred to as Fetal antigen 1 (FA1). By acting in juxtacrine as well as paracrine/autocrine manners, both forms have been shown to be active in the differentiation/proliferation process of various cell types. In adults, FA1/dlk has been demonstrated mainly within (neuro) endocrine tissues. In this study we investigated the presence of FA1/dlk in other parts of the developing and adult rat and human CNS. Using immunocytochemistry and in situ hybridization we found that in both species FA1/dlk was expressed in neurons of the Edinger-Westphal's nucleus as well as in substantia nigra, ventral tegmental area (VTA), locus coeruleus and in certain parts of the raphe nuclei.

Aged↗

PubMed2001

Quantitative magnetic resonance imaging as marker of synovial membrane regeneration and recurrence of synovitis after arthroscopic knee joint synovectomy: a one year follow up study.

OBJECTIVES: By repeated magnetic resonance imaging (MRI) to study synovial membrane regeneration and recurrence of synovitis after arthroscopic knee joint synovectomy in patients with rheumatoid arthritis (RA) and other (non-RA) causes of persistent knee joint synovitis. METHODS: Contrast enhanced MRI was performed in 15 knees (nine RA, six non-RA) before and one day, seven days, two months, and 12 months after arthroscopic synovectomy. Synovial membrane volumes, joint effusion volumes, and cartilage and bone destruction were assessed on each MRI set. Baseline microscopic and macroscopic assessments of synovitis and baseline and follow up standard clinical and biochemical examinations were available. RESULTS: Synovial membrane and joint fluid volumes were significantly reduced two and 12 months after synovectomy. However, MRI signs of recurrent synovitis were already present in most knees at two months. No significant differences between volumes in RA and non-RA knees were seen. Synovial membrane volumes at two months were significantly inversely correlated with the duration of clinical remission, for all knees considered together (Spearman's correlation r(s)=-0.67; p<0.05), for RA knees (r(s)=-0.76; p<0.05), and for non-RA knees (r(s)=-0.83; p<0.05). Baseline volumes were not significantly correlated with clinical outcome. Only three knees (all RA) showed erosive progression. The rate of erosive progression was not correlated with MRI volumes or with clinical or biochemical parameters. CONCLUSION: The synovial membrane had regenerated two months after arthroscopic knee joint synovectomy and despite significant volume reductions compared with baseline it often showed signs of recurrent synovitis. MRI seems to be valuable as a marker of inflammation, destruction and, perhaps, as a predictor of therapeutic outcome in arthritis.

Adult↗

PubMed2001

Fetal antigen 1 in healthy adults and patients with pituitary disease: relation to physiological, pathological, and pharmacological GH levels.

Immunohistochemical analysis of the distribution of human fetal antigen 1 (FA1) in adult human tissues has demonstrated a strong association between FA1 and (neuro)endocrine structures. In the anterior pituitary gland FA1 was colocalized with GH, and the present study was performed to evaluate a possible relationship between GH and FA1. FA1 and GH levels were measured during a 24-h period at 20-min intervals. In contrast to the known GH peaks during 24-h sampling, there was no detectable FA1 peak. The FA1 responses to placebo were not significantly different from the responses to the combination of pyridostigmine and GHRH. No significant difference was found between basal FA1 (nanograms per ml) levels [median (minimum-maximum)] in healthy adults [n = 40; 28.6 ng/ml (12.5-72.0)], acromegalic patients [n = 11; 31.0 ng/ml (21.6-56.3)], and patients with GH deficiency [n = 22; 32.1 ng/ml (13.4-108.7)]. FA1 levels were significantly reduced, in the six of seven acromegalic GH responders to octreotide, from [median (minimum-maximum)] 30.6 ng/ml (20.0-43.1) to 20.3 (13.9-30.2; P < 0.02). There was no significant change during placebo. FA1 levels were significantly increased compared with placebo values during 3 months of GH therapy. The increase in FA1 levels was significantly higher than the change during placebo (P < 0.003). In conclusion, a common secretory and stimulatory pathway for FA1 and GH in healthy adults has been ruled out. However, we found that pharmacologically induced changes in GH levels during weeks to months had a corresponding direct or indirect effect on FA1 levels in patients with GH deficiency or acromegaly. However, a direct effect of octreotide on FA1 levels, independent of GH levels, has not been ruled out.

Acromegaly↗

PubMed2000

Complications and re-operation rate after tension-band wiring of olecranon fractures.

Tension-band wire fixation of olecranon fractures leads to a high re-operation rate because of the need to remove the metalware. This problem has commonly been thought to be related mainly to the backing-out of the Kirschner wires. A retrospective study was carried out in 55 patients with displaced olecranon fractures operated on with the tension-band wiring technique, in whom there was an overall 71.7% re-operation rate. Complications were few and minor in most patients. The main reason for the removal of the metalware was a direct complaint from the patient (in 61.3% of all removals). A literature review analyzing the causes of metalware removal is also presented.

Adult↗

PubMed2000

Flow cytometric detection of growth factor receptors in autografts and analysis of growth factor concentrations in autologous stem cell transplantation: possible significance for platelet recovery.

In order to improve prediction of hematopoietic recovery, we conducted a pilot study, analyzing the significance of growth factor receptor expression in autografts as well as endogenous growth factor levels in blood before, during and after stem cell transplantation. Three early acting (stem cell factor (SCF), Flt3 ligand (Flt3) and fetal antigen 1 (FA1)) and three lineage-specific growth factors (EPO, G-CSF and thrombopoietin (Tpo)) were analyzed by ELISA in 16 patients with multiple myeloma (MM) and 16 patients with non-Hodgkin's lymphoma (NHL). The relative number of SCF, Flt3, Tpo and G-CSF receptor positive, CD34+ progenitor cells were measured by flow cytometry in the leukapheresis product used for transplantation in a subgroup of 15 patients (NHL, n = 8, MM, n = 7). Three factors were identified as having a significant impact on platelet recovery. First, the level of Tpo in blood at the time of the nadir (day +7). Second, the percentage of re-infused thrombopoietin receptor positive progenitors and finally, the percentage of Flt3 receptor positive progenitors. On the other hand, none of the analyzed factors significantly predicted myeloid or erythroid recovery. These findings need to be confirmed in prospectively designed studies.

Adjuvants, Immunologic↗

PubMed2000

Does fetal antigen 1 (FA1) identify cells with regenerative, endocrine and neuroendocrine potentials? A study of FA1 in embryonic, fetal, and placental tissue and in maternal circulation.

Fetal antigen 1 (FA1) is a circulating EGF multidomain glycoprotein. FA1 and its membrane-associated precursor is defined by the mRNAs referred to as delta-like (dlk), preadipocyte factor 1 (pref-1) or zona glomerulosa-specific factor (ZOG). Using a polyclonal antibody recognising both forms, the localisation of FA1/dlk was analysed in embryonic and fetal tissues between week 5 to 25 of gestation and related to germinal origin and development. FA1 was observed in endodermally derived hepatocytes, glandular cells of the pancreas anlage, and in respiratory epithelial cells. FA1 was also present in mesodermally derived cells of the renal proximal tubules, adrenal cortex, Leydig and Hilus cells of the testes and ovaries, fetal chondroblasts, and skeletal myotubes. Ectodermally derived neuro- and adenohypophysial cells, cells in the floor of the 3rd ventricle and plexus choroideus were also FA1 positive. The number of cells expressing FA1 decreased during fetal development where the expression became restricted to specific functional cells. Epidermis, gut epithelium, gall bladder, blood cells, spleen, thyroid gland, salivary glands, and smooth muscle cells were FA1 negative. Analysis of extra-embryonic tissues from normal and pathological pregnancies revealed FA1 in stromal cells surrounding the blood islands of the yolk sac as well as in placental fibroblasts where the expression was most pronounced in diploid, androgenic complete hydatidiform moles. However, as measured by ELISA, the circulating maternal FA1 levels in complete moles were not different from normal pregnancies. The results presented suggest that FA1 is a growth and/or differentiation factor extensively expressed in immature cells and down-regulated during fetal development. FA1 down-regulation was associated with a shift in the subcellular localisation indicating differential post-translational/post-transcriptional modifications during fetal development. FA1 may be a new marker of cellular subtypes with a regenerative potential and of specific cells with endocrine or neuroendocrine functions.

Biomarkers↗

PubMed2000

Follow-up of volar plate interposition arthroplasty (Tupper) of the metacarpophalangeal joints in rheumatoid hands: preliminary findings.

We present the results of a three-year follow-up study of 59 interposition volar plate arthroplasties (Tupper) on metacarpophalangeal joints in 13 patients with erosive rheumatoid arthritis. The median age at the time of operation was 60 years (range 45-77). All patients reported lasting pain relief at rest. Improvement of hand function was, however, less satisfactory as both grip and pinch strength were compromised in all patients. Seven patients were satisfied with the outcome whereas six complained of stiffness in the operated joints. All but one patient concluded that they would have the operation again if necessary.

Aged↗

PubMed2000

Weilby-Burton arthroplasty of the trapeziometacarpal joint of the thumb.

Twenty-three patients (25 thumbs) were treated by tendon interposition arthroplasty for trapeziometacarpal arthrosis as described by Weilby and modified slightly as described by Burton and Pellegrini. There was good (4/25, 16%) or complete (19/25, 76%) pain relief in 23 (92%) of the cases. Activities of daily living were generally easier. Mobility and strength of the thumb were satisfactory. One patient had signs of instability during a stress test. We conclude that our technique produces a stable and pain-free thumb joint. However, careful selection of the patients for this procedure is essential, and the patient must be given comprehensive information about all stages.

Adult↗

PubMed1999

[Fatal poisoning with Letigen].

The anorexic agent Letigen, which contains 200 mg coffeine and 20 mg ephedrine, has been extensively used during the last decade. The case report describes a 19 year-old woman who ingested 50 Letigen tablets in a suicidal attempt. She developed severe toxic manifestations from the heart, CNS, muscles, liver and kidneys leading to several cardiac arrests, and died subsequently of cerebral oedema and incarceration on the fourth day of hospitalization. Because of the potentially life-threatening intoxication following an overdose, prescription of Letigen must be carefully administered.

Adult↗

PubMed1999

Knee injury and obesity in patients undergoing total knee replacement: a retrospective study in 115 patients.

The prevalence of obesity and previous knee injury was assessed in a retrospective study of 115 patients under-going total knee replacement due to osteoarthritis. Obesity was considered a contributing factor in the development of osteoarthritis in 37% of the patients, and 33% of the patients had had an injury to the knee in question. Unilateral osteoarthritis was significantly more frequent than bilateral osteoarthritis among patients with a history of previous knee injury. The association of previous injury to the knee and unilateral osteoarthritis was stronger in men than women. Aggressive treatment of patients with knee injuries seems warranted.

Adult↗

PubMed1999

Indirect measurement of mitochondrial proton leak and its application.

In mitochondria, ATP synthesis is coupled to oxygen consumption by the proton electrochemical gradient established across the mitochondrial inner membrane in a process termed oxidative phosphorylation. It has long been known from stoichiometric studies that ATP synthesis is not perfectly coupled to oxygen consumption. The major inefficiency in the system is leakage of protons across the mitochondrial inner membrane driven by the proton electrochemical gradient. The kinetics of the proton leak can be determined indirectly, by measuring the oxygen consumption of mitochondria under non-phosphorylating conditions (plus oligomycin) as a function of the proton electrochemical gradient. This experimental system provides a convenient means to investigate inner membrane permeability to protons and the effect of factors that may effect that permeability. In this paper we review some results from our laboratory of indirect measurement of mitochondrial proton leak and how it has been applied to investigate the effect of aging, obesity and thyroid status on proton leak. The results show that (i) proton leak in isolated liver mitochondria is not significantly different in a comparison of young and old rats, in contrast (ii) there is an apparent increase in proton leak in in situ mitochondria in hepatocytes from old rats when compared to those from young rats, (iii) proton leak in neuronal mitochondria in situ in synaptosomes is not significantly different in young and old rats, (iv) proton leak is greater in isolated liver mitochondria from ob/ob mice compared to lean controls, (v) acute leptin (OB protein) administration restores the increased leak rate in isolated liver mitochondria from ob/ob mice to that of lean controls, (vi) administration of thyroid hormone (T3) increases proton leak in rat muscle mitochondria, and (vii) proton leak in muscle mitochondria is insensitive to the presence of GDP. It is proposed that the experimental system described here for measuring proton leak, is an ideal functional assay for determining whether the novel uncoupling proteins increase inner membrane permeability to protons.

Aging↗

PubMed1999

Fetal antigen 1, a member of the epidermal growth factor superfamily, in neurofibromas and serum from patients with neurofibromatosis type 1.

Fetal antigen 1 (FA1) is a 26-32 kDa glycoprotein containing six epidermal growth factor-like repeats closely related to the delta/notch/serrate proteins in Drosophila. FA1 has been shown to be involved in cell differentiation in a juxtacrine/paracrine manner. As neurofibromatosis type 1 (NF-1), also called von Recklinghausen disease, involves aberrant growth of tissues derived from the neural crest, the expression of FA1 was examined in neurofibroma skin biopsies and serum from patients with NF-1. FA1 was found in the spindle cells of all (n = 10) skin tumour specimens from adult NF-1 patients, whereas normal dermis was FA1 negative. In adults, the serum FA1 levels were significantly higher in NF-1 patients (n = 13) than in normal healthy controls (n = 177) (P = 0.037). In the group of children with NF-1 (n = 9), significantly higher serum FA1 levels were observed in those known to have complications with cerebral or spinal involvement (n = 4) (P = 0.014). The presence of FA1 in neurofibroma specimens and the elevated serum levels in patients with NF-1 suggests that FA1 may be involved in the pathogenesis of NF-1, perhaps acting as a growth promoting factor.

Adolescent↗

PubMed1999

Fetal antigen 1, an EGF multidomain protein in the sex hormone-producing cells of the gonads and the microenvironment of germ cells.

Fetal antigen 1 (FA1), an epidermal growth factor (EGF) multidomain glycoprotein, was investigated in the human reproductive system. Immunohistochemical analysis of the male reproductive system revealed staining for FA1 in the Leydig cells only. Concentrations of FA1 in seminal plasma and serum were similar and significantly correlated in weekly samples from three men (P < 0.0065). The concentrations in seminal plasma from vasectomized men (n = 4) were not significantly different from those of normal men (n = 187). The concentration of FA1 in seminal plasma was significantly correlated with the sperm counts of normozoospermic men (P < 0.0001), and significantly higher in seminal plasma from men with sperm counts > 20 x 10(6)/ml, compared with those with counts </= 20 x 10(6)/ml (P < 0. 0001). Immunohistochemical analysis of the ovary showed the presence of FA1 in the theca interna and the hilus cells but not in the granulosa cells or the oocyte. In follicular fluid the concentration of FA1 (median; 73.3 ng/ml, n = 28) was three times higher than that of serum (median; 23.8 ng/ml). These data suggest a role for this novel member of the EGF superfamily in relation to human reproduction, but further experiments are needed to define the biological function and to elucidate its clinical potential.

Adult↗

PubMed1999

Thermal instability of the trimeric structure of the N-terminal propeptide of human procollagen type I in relation to assay technology.

The N-terminal propeptide of procollagen type I (PINP) appeared in two peaks after size chromatography. The high-molecular weight form was transformed to the low-molecular weight form during incubation at 37 degreesC, whereas the low-molecular weight form remained unchanged. The PINP concentrations in amniotic fluid and sera remained unchanged during 37 degreesC incubation when measured using an ELISA; however, concentrations decreased by 89-93% when measured using an RIA. The ELISA:RIA ratio varied from 1.1 to 2.9 in these fluids because of different size distributions and the inability of the RIA to measure the low-molecular weight form. Thermal transition of the high-molecular weight form caused a change in its elution volume but did not change its migration in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mass spectrometry revealed identical results for both forms. We reached the following conclusions: (a) the trimeric structure of PINP is unstable at 37 degreesC; (b) the two molecular forms represent intact alpha1 chains in trimeric and monomeric forms; (c) thermal transition is an ongoing in vivo process; and (d) this is important in the choice of assay technology.

Amniotic Fluid↗

PubMed1998

[Shoulder instability].

The importance of the labrum and glenohumeral ligament complex for the stability of the shoulder joint has been known since the beginning of this century. Shoulder instability may be classified into two large groups. TUBS, characterized by Traumatic, Unidirectional instability and Bankart lesion which often requires Surgery. The second group AMBRI, is characterized by Atraumatic, Multidirectional, Bilateral instability that often responds to Rehabilitation, but in case of surgery Inferior capsular shift is indicated. The high recurrence rate after primary traumatic anterior dislocation in young adults has caused an ongoing discussion about the indications for primary surgery. Anatomical reconstruction focusing on the pathoanatomy is recommended due to better results and a lower complication rate as compared to non-anatomical reconstruction that alters the normal anatomy and kinematics. The recurrence rate after arthroscopic Bankart repair is still generally higher than after open surgery but may be improved by better patient selection.

Adult↗

PubMed1998

Quantification of the N-terminal propeptide of human procollagen type I (PINP): comparison of ELISA and RIA with respect to different molecular forms.

This paper compares the results of procollagen type I N-terminal propeptide (PINP) quantification by radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA). PINP in serum from a patient with uremic hyperparathyroidism was measured in RIA and ELISA to 20 micrograms l-1 and 116 micrograms l-1 and the corresponding concentrations in dialysis fluid were 94.5 micrograms l-1 and 140 micrograms l-1, respectively. PINP antigen appears in two distinct peaks following size chromatography and the two peak fractions display immunological identity and identical M(r)'s (27 kDa: SDS-PAGE). Analysis of fractions from size separated amniotic fluid, serum and dialysis fluid demonstrated that the RIA failed to measure the low molecular weight form of PINP. However, the anti-PINP supplied with the RIA-kit and the anti-PINP applied in the ELISA reacted equally well with both molecular forms of PINP when analysed in a direct ELISA. It is concluded that the major difference in the ELISA and RIA results is due to assay efficacy with respect to the low molecular weight form of PINP.

Amniotic Fluid↗

PubMed1998

Interlocking nailing of humeral shaft fractures.

: In this retrospective study 48 humeral shaft fractures in 48 patients were operated on using the Seidel interlocking nail. The length of follow-up ranged from 6 to 60 months (median, 26 months). The treatment of fractures was satisfactory with the Seidel nail, but we emphasize the importance of countersinking the tip of the nail into the humeral head to avoid impingement. In 5 of 12 patients with non-unions, the procedure failed, and we found that the distal locking seemed to be inadequate. Pathological fractures (i.e., those caused by metastatic tumors) were all efficiently treated with the Seidel nail.

Adult↗

PubMed1997

Fetal antigen 1 (FA1), a circulating member of the epidermal growth factor (EGF) superfamily: ELISA development, physiology and metabolism in relation to renal function.

We describe an ELISA technique for quantification of fetal antigen 1 (FA1), a glycoprotein belonging to the EGF-superfamily. The ELISA is based on immunospecifically purified polyclonal antibodies and has a dynamic range of 0.7-5.3 ng/ml, intra- and inter-assay C.V.s of less than 3.2% and an average recovery of 105% in serum and 98% in urine. Comparison of FA1 in amniotic fluid, serum and urine revealed parallel titration curves, identical elution volumes following size chromatography, immunological identity and similar profiles when analysed by MALDI-MS. The reference interval for serum FA1 was 12.3-46.6 ng/ml and the levels were 10 times higher in patients with renal failure. FA1 showed no diurnal variation, no variation during the menstrual cycle and was not influenced by the acute phase reaction. In humans (n = 10) the renal clearance of FA1 was 11 ml/min and an identical high renal clearance was found in rats when expressed per 100 g body weight. In rats the initial increase in serum FA1 was 10 ng/ml/h following bilateral nephrectomy, explaining the increased serum concentrations of FA1 observed in patients with renal failure.

Acute-Phase Reaction↗