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Biomedical subjects

J Laursen

Publications and source records attributed to J Laursen.

At least 19 recordsLinked to original sources
PubMed2006

Computational fluid dynamics modelling of hydraulics and sedimentation in process reactors during aeration tank settling.

Aeration tank settling is a control method allowing settling in the process tank during high hydraulic load. The control method is patented. Aeration tank settling has been applied in several waste water treatment plants using the present design of the process tanks. Some process tank designs have shown to be more effective than others. To improve the design of less effective plants, computational fluid dynamics (CFD) modelling of hydraulics and sedimentation has been applied. This paper discusses the results at one particular plant experiencing problems with partly short-circuiting of the inlet and outlet causing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in the process tank. The model has allowed us to establish a clear picture of the problems arising at the plant during aeration tank settling. Secondly, several process tank design changes have been suggested and tested by means of computational fluid dynamics modelling. The most promising design changes have been found and reported.

Aerobiosis↗
PubMed2001

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. III. Zinc measured by X-ray fluorescence spectrometry.

The aim of the study was to measure the content of zinc (Zn) in liver tissue samples from Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver samples from Danes. Normal liver tissue samples was obtained at autopsy from 50 Greenlandic Inuit (27 men) with a median age of 61 years (range 23-83) and from 74 Danes (44 men) with a median age of 60 years (range 15-87). In the entire series, liver zinc content in Inuit was not significantly different compared with Danes. There was no significant gender difference in liver zinc content either in Inuit or in Danes. The content of zinc given as median (5-95 percentile) was in Inuit 3.809 mmol/kg dry liver (2.355-7.406), and in Danes 3.992 mmol/kg dry liver (2.499-8.645). There was a significant, positive correlation between liver zinc content and age in Danish women (r(s) = 0.43, p = 0.02), which could not be demonstrated in Danish men or in Inuit. Median hepatic zinc index (zinc content in mmol/kg dry weight divided by age in years) in Inuit was 0.073, and in Danes 0.080 (p = 0.3) without any significant difference between the two genders. In Inuit and Danes there was an inverse correlation between hepatic zinc index and age both in the two genders and in the entire series: Inuit: r(s) = -0.62, p < 0.0001; Danes: r(s) = -0.70, p < 0.0001. The results indicate that Inuit have liver zinc levels, which are similar to those found in Danes.

Adolescent↗
PubMed2001

Pigs expressing salivary phytase produce low-phosphorus manure.

To address the problem of manure-based environmental pollution in the pork industry, we have developed the phytase transgenic pig. The saliva of these pigs contains the enzyme phytase, which allows the pigs to digest the phosphorus in phytate, the most abundant source of phosphorus in the pig diet. Without this enzyme, phytate phosphorus passes undigested into manure to become the single most important manure pollutant of pork production. We show here that salivary phytase provides essentially complete digestion of dietary phytate phosphorus, relieves the requirement for inorganic phosphate supplements, and reduces fecal phosphorus output by up to 75%. These pigs offer a unique biological approach to the management of phosphorus nutrition and environmental pollution in the pork industry.

6-Phytase↗
PubMed2001

Recessive resistance in Pisum sativum and potyvirus pathotype resolved in a gene-for-cistron correspondence between host and virus.

Pea seed-borne mosaic potyvirus (PSbMV) isolates are divided into pathotypes P-1, P-2, and P-4 according to their infection profile on a panel of Pisum sativum lines. P. sativum PI 269818 is resistant to P-1 and P-2 isolates and is susceptible to P-4 isolates. Resistance to P-1 is inherited as a single recessive gene, denoted sbm-1, and the pathogenicity determinant has previously been mapped to the virus-coded protein VPg. In the cultivar Bonneville, a second recessive gene, sbm-2, confers specific resistance to P-2. By exchanging cistrons between a P-2 and a P-4 isolate, the P3-6k1 cistron was identified as the PSbMV host-specific pathogenicity determinant on Bonneville. Exchange of P3-6k1 did not affect infection on PI 269818, and infection of Bonneville was not altered by substitution of the VPg cistron, indicating that P3-6k1 and VPg are independent determinants of pathotype-specific infectivity. On PI 269818 the pathogenicity determinant of both P-1 and P-2 mapped to the N terminus of VPg. This suggests that VPg from the P-1 and P-2 isolates are functionally similar on this host and that resistance to P-1 and P-2 in PI 269818 may operate by the same mechanism. Identification of VPg-sbm-1 and P3-6k1-sbm-2 as independent pairs of genetic interactors between PSbMV and P. sativum provides a simple explanation of the three known pathotypes of PSbMV. Furthermore, analysis of beta-glucuronidase-tagged P-2 virus indicated that sbm-2 resistance affected an early step in infection, implying that the P3-6k1 region plays a critical role in potyvirus replication or cell-to-cell movement.

Genes↗
PubMed2000

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. II. Iron measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of iron (Fe) in liver tissue samples from urbanized Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver tissue samples from urbanized Danes. Normal liver tissue samples were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 23-83) and from 72 Danes (42 men, 30 women) with a median age of 62 years (range 15-87). In the entire series, there was no significant difference between liver iron in Inuit compared with Danes. Likewise, there was no significant gender difference concerning liver iron content, either in Inuit or in Danes. The median iron content (with 5-95 percentile) in Inuit was 17.23 mmol/kg dry liver (5.80-91.80) and in Danes 16.51 mmol/kg dry liver (7.83-39.05). However, when stratified according to age, a trend was revealed showing that Inuit men and women < or = 50 years had a lower liver iron content than Danes (p = 0.05 and p = 0.08) whereas Inuit men and women > 50 years had a higher liver iron content than Danes (p = 0.18 and p = 0.02). There was a significant correlation between liver iron content and age in both Inuit men (rs = 0.49, p = 0.01) and in women (rs = 0.64, p = 0.003), but not in Danes. In Inuit, the median hepatic iron index (liver iron content divided by age) was 0.33 in men and 0.32 in women. The median estimated iron content in the whole liver was 6.54 mmol (365 mg) in Inuit men and 5.41 mmol (302 mg) in Inuit women (p = 0.6). There was no correlation between hepatic iron index and age. In Danes, the median hepatic iron index was 0.46 in men and 0.29 in women (p = 0.01). There was a significant inverse correlation between hepatic iron index and age in the two genders and in the entire series (rs = -0.71, p = 0.0001). The results indicate that young and middle-aged urbanized Inuit have slightly smaller iron stores than urbanized Danes, whereas elderly Inuit have higher iron stores than Danes. In Danes, iron stores plateau at 30 to 40 years of age in men and some years after the menopause in women. In Inuit, iron stores continue to increase in old age, probably to due a lifelong dietary intake of haem iron.

Adolescent↗
PubMed1998

Novel salivary gland specific binding elements located in the PSP proximal enhancer core.

The murine parotid secretory protein (PSP) gene is expressed selectively at high levels in parotid and sublingual salivary glands. Previously, the transcriptional activity of a PSP mini-gene, called Lama, was shown to be dependent on a 1.5 kb region located 3 kb upstream of the transcription start site. Here, functional studies in transgenic mice demonstrate that this proximal regulatory region has properties of a parotid and sublingual gland specific enhancer. Protein-binding experiments identify multiple sequence-specific binding complexes spanning the entire 1.5 kb enhancer region. Several sequence elements bound specifically by parotid and/or sublingual gland nuclear extracts, including consensus binding elements for previously described transcription factors as well as novel binding elements are located in the proximal enhancer region. A deletion analysis of the enhancer region in transgenic mice identified a core sequence of 700 bp. This region contains five elements bound specifically by nuclear proteins isolated from the PSP-expressing parotid and sublingual glands. Two of these elements, denoted parotid gland element I (PGE I) and sublingual gland element I (SLE I), are novel salivary gland specific binding elements, bound uniquely by parotid and sublingual gland nuclear extracts, respectively.

Amino Acid Sequence↗
PubMed1998

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. I. Sulphur, chlorine, potassium and bromine measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of the elements Sulphur (S), Chlorine (C1), Potassium (K) and Bromine (Br) in normal liver tissue samples from Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in normal liver tissue samples from Danes. Liver tissue sample were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 20-83) and from 74 Danes (44 men, 30 women) with a median age of 52 years (range 15-87). In Inuit, the content of elements given as median and (5-95 percentile) was: sulphur, 108.07 mmol/kg dry liver (86.78 - 169.44); chlorine, 92.16 mmol/kg dry liver (45.39-128.42); potassium, 181.66 mmol/kg dry liver (146.41-236.35); bromine, 0.0901 mmol/kg dry liver (0.0563-0.1589). In Danes, the corresponding values were: sulphur, 147.58 mmol/kg dry liver (70.41-236.81); chlorine, 96.95 mmol/kg dry liver (54.01-162.52); potassium, 198.40 mmol/kg dry liver (150.68-256.37); bromine, 0.1101 mmol/kg dry liver (0.0701 - 0.4203). None of the elements displayed any significant gender difference, neither in Inuit nor in Danes. Inuit had a lower liver content of sulphur (p < 0.0001), potassium (p < 0.008) and bromine (p < 0.002) as compared with Danes.

Adult↗
PubMed1998

Allele-specific expression of the PSP gene in the mouse sublingual glands.

There are two known alleles of the mouse parotid secretory protein (PSP) gene: Pspa and Pspb. Pspa is carried by DBA/2J mice and Pspb is carried by C57BL/6J mice. Eighty-eight mice derived from a F1(C57BL/6J x DBA/2J) to DBA/2J backcross were analysed for PSP mRNA expression in the sublingual glands. Expression was found in heterozygous mice only. This indicates that only Pspb is expressed in this tissue. Furthermore, it maps the allele-specific sublingual gland determinant within 3.4 cM of Psp. Previous analysis of Pspb identified an enhancer-like region in position -4.6 to -3.1 kb that was necessary for transgene expression in the sublingual glands. Here it is shown that the corresponding region in Pspa enhances transgene expression in the sublingual glands as efficiently. The implications for regulation of PSP mRNA expression in the sublingual glands are discussed.

Alleles↗
PubMed1998

The main regulatory region in the murine PSP gene is a parotid gland enhancer.

The murine PSP gene is expressed at a high-level in the parotid glands. To extend the knowledge of parotid gland expression and develop tools for expression of heterologous proteins in this tissue, the regulation of the PSP gene was studied using transgenic mice. High-level parotid gland expression of the PSP gene was indicated to depend on a novel regulatory region situated between -8.0 and -6.5 kb. Together with previous results this indicates that the main regulatory elements in the PSP gene are situated between -8.0 to -3.1 kb. This region was shown to activate a heterologus SV40 early promoter in the parotid glands of transgenic mice, suggesting that the PSP gene is controlled by enhancer sequences. A novel Psp derived 9.7 kb parotid gland expression cassette, Lama IV, carrying all known regulatory regions in the PSP gene was expressed at high-levels in the parotid glands and should prove highly useful for expression of heterologous proteins in the saliva of transgenic mice.

Animals↗
PubMed1997

A cassette for high-level expression in the mouse salivary glands.

Expression in the mouse salivary glands may be used as a model system for studies involving oral cavity delivery of gene products. Previously, sequences from the mouse Psp gene were used to build a minigene construct denoted 'Lama'. This construct was used as a cassette for expression of human factor VIII light chain in mouse saliva. However, whereas the endogenous Psp mRNA is the most abundant protein-coding transcript in the parotid glands, the Lama mRNA was expressed below 1% of the level of Psp mRNA in these glands. Here, we show that a 25-kb cosmid-derived DNA fragment (PspX25) carrying the structural gene and large flanking areas of Psp is expressed in all 14 analysed lines in the parotid glands. The average level of transgene expression was estimated to be 45% of that of the endogenous Psp gene. More importantly, it was possible to transfer PspX25's ability for high-level parotid gland expression to the Lama construct.

Animals↗
PubMed1988

Nimodipine treatment of subarachnoid hemorrhage.

In a pilot study of 6 patients with subarachnoid hemorrhage caused by a ruptured intracranial (grade IV (Hunt and Hess) aneurysm the hemodynamics and plasma-nimodipine concentrations have been observed during a 3-week period of treatment. We found that 3 patients developed reversible hypotension during the nimodipine treatment and that the hypotension tendency could be related to the plasma-nimodipine level and not to a more or less severe sensitivity to nimodipine. Repeated measurements of blood pressure, plasma-nimodipine and regional cerebral blood flow (rCBF) are necessary for the purpose of obtaining the optimum treatment and for evaluating the effect of treatment.

Adult↗
PubMed1987

Spinal epidural hematomas.

During the period 1943-1985 six patients were operated for spinal epidural hematomas at the department of neurosurgery of the University Hospital of Arhus. It is essential to perform acute laminectomy in case of rapidly increasing neurological symptoms. In the case of slowly increasing symptoms operation may provide a good result even if it is performed a week after the onset of symptoms. It is important to watch patients with fracture/dislocations of the spine closely during the first weeks after a trauma. If they develop neurological symptoms the patients should immediately be transferred to the department of neurosurgery with a view of

Accidental Falls↗
PubMed1987

Elements in normal and cirrhotic human liver tissue. II. Potassium, sulphur, chlorine and bromine measured by X-ray fluorescence spectrometry.

Elements (K, S, Cl, Br) were measured by X-ray fluorescence spectrometry in normal liver tissue obtained at autopsy from 74 subjects (44 male, 30 female), median age 62 years (range 20-87), and in cirrhotic liver tissue from 27 subjects (14 alcoholic, 13 non-alcoholic cirrhosis). The element content (median and 5-95 percentile interval) in normal livers in mmol/kg dry tissue was: K, 198.75 (150.95-256.42); S, 147.60 (73.86-233.97); Cl, 98.73 (69.51-163.55); Br, 0.1101 (0.0701-0.4205). None of the elements displayed any sex difference. There were correlations between the content of Br and Cl (r = 0.26, P less than 0.05) and Br and K (r = 0.24, p less than 0.05). In both groups of cirrhotic livers, K, S and Cl content was within the normal range. Median Br content was above normal both in alcoholic (0.2265 mmol/kg, P less than 0.01) and non-alcoholic cirrhotic livers (0.2228 mmol/kg, P less than 0.01).

Adult↗
PubMed1986

Chronic facial pain following diseases affecting the maxillary antrum. The influence of peripheral impulses from the maxillary air sinus is not significant in their maintenance.

For the purpose of examining the significance of a pain focus in the maxillary air sinus denervation of the mucosa of the sinus by transantral maxillary nerve section was performed. The material comprises 20 patients with pain in the distribution of the infraorbital nerve and previous disease of the relevant sinus. All patients had been treated previously without any benefit from peripheral surgery of the infraorbital nerve. Only 20% had any benefit of the proximal avulsion for more than three months. It is concluded that impulses from the mucosa of the maxillary sinus do not play any part in the occurrence or persistence of facial pain in this highly selected material.

Adult↗