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H Haugen

Publications and source records attributed to H Haugen.

14 recordsLinked to original sources
PubMed2006

A novel processing method for injection-molded polyether-urethane scaffolds. Part 1: processing.

A large-scale scaffold processing method with injection molding has been successfully developed. Water was used as afoaming agent for the new technique. NaCl was used as a porogen to achieve an open-cell structure. Organic solvents, which are common foaming agents for polyurethane, where not used. Toxic remains in the polymer were therefore prevented. Pore size and porosity was adjustable through process parameters. A parameter study showed that an increase in injection pressure, plasticize speed, cylinder, and mold temperature raised the mean pore diameter. The porosity also could be mended by the cylinder and mold temperature, in addition to NaCl concentration. It was possible to produce scaffolds with a porosity of 64 +/- 3%, a pore size distribution from 30-450 microm, and a mean pore diameter of 270 +/- 90 microm. The interconnective pores were found to lie between 5 and 58 microm.

Biocompatible Materials↗
PubMed2006

A novel processing method for injection-molded polyether-urethane scaffolds. Part 2: cellular interactions.

A large-scale scaffold processing method with injection molding has been successfully developed. Water was used as a foaming agent for the new technique. NaCl was used as a porogen to achieve an open-cell structure. Organic solvents, which are common foaming agents for polyurethane, where not used. Toxic remains in the polymer were therefore prevented. Biocompatibility tested gave a mean optical density of 81% from WST-1 proliferation assay. In comparison to the previously study processing method, hot pressing (Haugen H, Ried V, Brunner M, Will J, Wintermantel E. J Mater Sci: Mater Med2004;15:343-346), the current scaffolds had an increase of 20% of the mean optical density. Cell seeding showed that human fibroblasts adhered to the surface and proliferated. The spread of the adhered fibroblasts was uniform on the surface. A quantitative MTT analysis proved that there was a significant (p < 0.01) increase in the OD level after 7 and 14 days of incubation. This cell layer thickened with increased incubation time from 7 to 14 days (p < 0.05) and had typical fibroblast morphology.

Biocompatible Materials↗
PubMed2005

Biostability of polyether-urethane scaffolds: a comparison of two novel processing methods and the effect of higher gamma-irradiation dose.

This article deals with enzyme-induced biodegradation behavior of thermoplastic polyether-urethane (TPU). Porous scaffolds were processed by a new foaming method applied in hot pressing and injection molding. The scaffolds were subsequently gamma sterilized. The samples were incubated with cholesterol esterase (CE) for 28 days to simulate an enzymatic degradation order to assess polymer biostability. The main focus of degradation products was the most toxic one: methylene dianiline (MDA). LC/MS was used to separate the breakdown products and to identify possible MDA amounts. The results showed that (a) the hot-pressed sample released an MDA amount almost twice as large (0.26 ng +/- 0.008) as that of the injection-molded samples (0.15 ng +/- 0.003) after incubation with enzyme activity in the physiological range, and (b) a tenfold increase in CE activity revealed considerably higher MDA amounts (7540.0 ng +/- 0.004). This enzyme concentration is physiologically unlikely, however, but may occur for extreme high inflammation behavior. Even for extremely high levels of CE enzyme, the scaffold will not discharge MDA above toxic levels. The injection-molded samples sterilized at 25 kGy seem to represent the most promising processing method. Therefore, the new injection-molding foaming process of polyether-urethane can be considered appropriate for use as a biomaterial.

Animals↗
PubMed2004

Water as foaming agent for open cell polyurethane structures.

The problem of moisture in polymer processing is known to any polymer engineer, as air bubbles may be formed. Hence granulates are generally dried prior to manufacturing. This study tried to develop a novel processing methods for scaffolds with controlled moisture content in thermoplastic polyurethane. The common foaming agents for polyurethane are organic solvents, whose residues remaining in the scaffold may be harmful to adherent cells, protein growth factors or nearby tissues. Water was used as a foaming agent and NaCl was used as porogens to achieve an open-cell structure. The polyether-polyurethane samples were processed in a heated press, and achieved a porosity of 64%. The pore size ranged between 50 and 500 microm. Human fibroblasts adhered and proliferate in the scaffold. A non-toxic production process was developed to manufacture a porous structure with a thermoplastic polyether-polyurethane. The process enables a mass-production of samples with adjustable pore size and porosity. In contrast to an existing method (solvent casting), the processing of the samples was not limited by its thickness. The process parameters, which attribute mostly to the pore building, were filling volume, temperature, NaCl-concentration and water-uptake rate.

Air↗
PubMed2001

Interleukin 20: discovery, receptor identification, and role in epidermal function.

A structural, profile-based algorithm was used to identify interleukin 20 (IL-20), a novel IL-10 homolog. Chromosomal localization of IL-20 led to the discovery of an IL-10 family cytokine cluster. Overexpression of IL-20 in transgenic (TG) mice causes neonatal lethality with skin abnormalities including aberrant epidermal differentiation. Recombinant IL-20 protein stimulates a signal transduction pathway through STAT3 in a keratinocyte cell line, demonstrating a direct action of this ligand. An IL-20 receptor was identified as a heterodimer of two orphan class II cytokine receptor subunits. Both receptor subunits are expressed in skin and are dramatically upregulated in psoriatic skin. Taken together, these results demonstrate a role in epidermal function and psoriasis for IL-20, a novel cytokine identified solely by bioinformatics analysis.

Animals↗
PubMed2001

TACI-Ig neutralizes molecules critical for B cell development and autoimmune disease. impaired B cell maturation in mice lacking BLyS.

BLyS and APRIL have similar but distinct biological roles, mediated through two known TNF receptor family members, TACI and BCMA. We show that mice treated with TACI-Ig and TACI-Ig transgenic mice have fewer transitional T2 and mature B cells and reduced levels of circulating immunoglobulin. TACI-Ig treatment inhibits both the production of collagen-specific Abs and the progression of disease in a mouse model of rheumatoid arthritis. In BLyS-deficient mice, B cell development is blocked at the transitional T1 stage such that virtually no mature B cells are present, while B-1 cell numbers are relatively normal. These findings further elucidate the roles of BLyS and APRIL in modulating B cell development and suggest that BLyS is required for the development of most but not all mature B cell populations found in the periphery.

Animals↗
PubMed2000

TACI and BCMA are receptors for a TNF homologue implicated in B-cell autoimmune disease.

B cells are important in the development of autoimmune disorders by mechanisms involving dysregulated polyclonal B-cell activation, production of pathogenic antibodies, and co-stimulation of autoreactive T cells. zTNF4 (BLyS, BAFF, TALL-1, THANK) is a member of the tumour necrosis factor (TNF) ligand family that is a potent co-activator of B cells in vitro and in vivo. Here we identify two receptors for zTNF4 and demonstrate a relationship between zTNF4 and autoimmune disease. Transgenic animals overexpressing zTNF4 in lymphoid cells develop symptoms characteristic of systemic lupus erythaematosus (SLE) and expand a rare population of splenic B-Ia lymphocytes. In addition, circulating zTNF4 is more abundant in NZBWF1 and MRL-lpr/lpr mice during the onset and progression of SLE. We have identified two TNF receptor family members, TACI and BCMA, that bind zTNF4. Treatment of NZBWF1 mice with soluble TACI-Ig fusion protein inhibits the development of proteinuria and prolongs survival of the animals. These findings demonstrate the involvement of zTNF4 and its receptors in the development of SLE and identify TACI-Ig as a promising treatment of autoimmune disease in humans.

Amino Acid Sequence↗
PubMed2000

Outbreak of scabies in Norwegian nursing homes and home care patients: control and prevention.

Over a period of five months (October 1998-February 1999), an outbreak of scabies affected 19 persons associated with a nursing home in Oslo, Norway. Scabies was diagnosed in 13 patients; six long-term patients, five short-term patients also cared for at home, and two home care patients associated with the same institution. Six healthcare workers who had assisted with infected patients in their own homes were also diagnosed with scabies. Two separate index cases were found. Both had had pruritus for several months, diagnosed as eczema, and were repeatedly treated at dermatology outpatient clinics before the diagnosis was made. Both index cases were cared for at home and in the nursing home (short-term). Repeated treatments with permethrin were tried before effective treatment with benzyl benzoate. Altogether 370 persons (patients, staff, relatives) were treated. In June-July 1999, scabies was diagnosed in two other nursing homes; six patients or staff, and 156 persons were treated. Patients with scabies were contact isolated and disinfection and cleaning was performed. Simultaneous treatment and washing or disinfection of clothing, bedding and environment of all potentially affected individuals is imperative to control an outbreak of scabies.

Adult↗
PubMed1980

Excretion of casts and uromucoid in urine after prolonged heavy exercise.

Excretion of uromucoid, albumin and casts in urine were determined in twenty well-trained men, ten aged 20-30 years, and ten aged 50-60 years, before, during and after a 70 km cross country ski race. During the race there was only a slight increase in uromucoid excretion, but a marked increase in the excretion of casts and albumin. The older subjects had a tendency to lower urine output during the race compared to the younger group. Reduction of urine output below ca. 25 ml/h was accompanied by a conspicuous increase in urine cast and albumin concentrations, with only a slight increase in uromucoid concentration, and even a reduction in uromucoid excretion. No significant relationship was found between cast excretion and uromucoid concentration. Thus the gross cylindruria observed during longstanding exercise must be ascribed to other urinary factors facilitating the formation of casts.

Adult↗
PubMed1979

Uromucoid (Tamm-Horsfall's mucoprotein) in amniotic fluid and in urine in children.

Uromucoid (Tamm-Horsfall's mucoprotein) was not detected in amniotic fluid from pregnancies with gestational are 12-18 weeks, but was detected in 5 of 9 samples of amniotic fluid from full-term pregnancies, and in urine from all full-term infants investigated 1st day of life. This suggests that uromucoid excretion under normal conditions established near term. Change from intrauterine to extrauterine life may rapidly induce uromucoid excretion, as this protein was found in premature infants (32-34 weeks of gestation) at the 2nd day of life. Healthy newborn infants had a lower uromucoid concentration in urine than children 7--13 years old. In newborns with uncomplicated prematurity, idiopathic respiratory distress syndrome and full-term asphyxiated newborns, the uromucoid concentration in urine during the 1st week of life was not different from healthy newborn infants. Though uromucoid is found to be the major constituent of hyaline casts, the excretion of casts did not correlate to the uromucoid concentration.

Adolescent↗
PubMed1978

Uromucoid in normal urine.

Uromucoid was determined in urine from persons or various ages with normal kidney function by a radial immunodiffusion technique. Uromucoid concentration was inversely correlated to diuresis. Excretion rates showed a weak correlation to body surface area in young adults of both sexes. Children had a greater excretion of uromucoid per m2 than young adults, and even newborn had a considerable excretion. Elderly subjects had similar excretion rates to young adults. Excretion rates were uninfluenced by sex, salt load or diuresis, and no difference between day and night excretion rates was observed. Intraindividual fluctuations were small, and determination of uromucoid in one single night's urine therefore gives an adequate expression of the uromucoid excretion rate.

Adolescent↗
PubMed1978

Quantification of uromucoid: a simplified method.

As a replacement of current time consuming techniques, a radial immunodiffusion method which is suitable for routine determination of uromucoid in urine in described. The method is based on denaturation of uromucoid by sodium dodecyl sulphate at 37 degrees C before application on the immunoplates. A diffusion period of 30 h at 37 degrees C was chosen. The determination is uninfluenced by variations of urinary electrolytes, freezing and thawing, and storage at 4 degrees C for 3 weeks or at -20 degrees C for several months. The method can also be applied to lyophilized urines.

Electrophoresis, Polyacrylamide Gel↗
PubMedDate not supplied

Application of the Audioscan in the detection of carriers of genetic hearing loss.

The authors describe the establishment of normative stimulus parameters for the Audioscan, an automated sweep frequency audiometer, for its application in the detection of audiometric notches in carriers of recessive genetic hearing loss. A sweep rate of 30 s/octave over the frequency range 300 to 4000 Hz pulsing at 2.5 pulses/s at -5 dB with a step size of 5 dB were ultimately adopted. The criterion for notches was 15 dB or greater within the frequency range 500-3000 Hz. Adopting this criterion, 14.2% of control subjects had notches. Among parents of children with non-syndromal recessive hearing loss 55% were found to have notches. Notches were found more frequently among mothers and sisters than among fathers and brothers of the patients.

Adult↗