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Biomedical subjects

J Kangas

Publications and source records attributed to J Kangas.

At least 19 recordsLinked to original sources
PubMed2006

Histomorphometric analysis of poly-L/D-lactide 96/4 sutures in the gastrocnemius tendon of rabbits.

BACKGROUND: Common Achilles tendon ruptures are not usually fixed by bioabsorbable sutures due to limitations in their strength retention properties. Modern technology has made it possible to develop bioabsorbable sutures with prolonged strength retention. AIMS: To evaluate histologically tissue reactions of poly-L/D-lactide (PLDLA) sutures implanted in Achilles tendon of rabbits. MATERIAL AND METHODS: Fifteen rabbits were evaluated at 2, 6 and 12 weeks postoperatively, with five rabbits in each follow-up group. PLDLA monofilament sutures were implanted into the medial gastrocnemius tendon. Polyglyconate monofilament sutures with similar diameter (Maxon 4-0, Cyanamid of Great Britain Ltd., Gosport, UK) were implanted in the contralateral gastrocnemius tendon. The histology was studied in hard-resin embedded samples. The thickness of the formed fibrous tissue capsule was determined histomorphometrically. RESULTS: PLDLA led to formation of significantly thinner fibrous tissue capsule than Maxon sutures of the same diameter. Median thickness (PLDLA vs. Maxon) at two weeks was 5.26 vs.13.22 microm, at six weeks 11.66 vs. 80.97 microm, and at 12 weeks 10.63 vs. 17.59 microm (p<0.01). CONCLUSIONS: During the 12 week follow-up period, PLDLA sutures implanted intratendineously formed thinner fibrous capsule than Maxon sutures of the same diameter. The suture materials were not totally absorbed by 12 weeks.

Animals↗
PubMed2001

Comparison of strength properties of poly-L/D-lactide (PLDLA) 96/4 and polyglyconate (Maxon) sutures: in vitro, in the subcutis, and in the achilles tendon of rabbits.

Achilles tendon rupture is a common injury. Absorbable sutures are not commonly used because of their limited strength properties. Recently, sutures with prolonged strength retention properties have been developed. The aim of the study is to test the mechanical properties of recently developed poly-L/D-lactide (PLDLA) sutures in comparison with polyglyconate (Maxon) sutures. PLDLA (0.2 mm thick) and Maxon (4.0) sutures were studied in vitro by immersion in a buffered saline solution (pH 7.4). Tensile strength tests were done on sutures retrieved after 1-26 weeks. In vivo, they were implanted in the subcutis of 32 rabbits. Tensile strength tests were done on sutures retrieved after 1-6 weeks. The sutures were also used to repair the Achilles tendon in rabbits. Maximum force before breaking and percentage elongation of tendons were determined. Although PLDLA had a lower initial tensile strength than Maxon, PLDLA showed more prolonged tensile strength retention than Maxon. Tendons repaired with PLDLA, however, had a lower strength than Maxon-repaired tendons at six weeks (insignificant difference). PLDLA has more prolonged tensile strength properties compared with Maxon. Thus, PLDLA offers an alternative to Maxon in repair of the Achilles tendon.

Absorbable Implants↗
PubMed2001

Determination of gallic acid in wood dust as an indicator of oak content.

A high-performance liquid chromatography (HPLC) method was developed for the detection of extracted gallic acid in wood dust. Gallic acid is a polyphenol present in carcinogenic oak wood dust, but not in beech, ash, pine or spruce dusts, as confirmed by HPLC analyses. The method involved the extraction of gallic acid from the oak dust, followed by liquid chromatographic analysis. The correlation coefficient for the share of oak dust vs. the gallic acid concentration of wood dust was 0.995. The method was tested with oak wood dust samples collected on polycarbonate membrane filters during an 8 h workshift in a floor board factory, where the dust content of the air samples was determined gravimetrically. The oak dust and the gallic acid concentrations varied from 0.2 to 13.8 mg m-3 and from 0.03 to 3.8 micrograms m-3, respectively. These parameters were linearly correlated with a correlation coefficient of 0.95. The airborne gallic acid determination is a useful technique to confirm occupational exposure to oak wood dust, a recognized human carcinogen.

Carcinogens↗
PubMed2001

Mutations induced by 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) in cecum and proximal and distal colon of lacI transgenic rats.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a food-borne mutagen and carcinogen that induces tumors of the colon and the prostate gland in male rats and of the mammary gland in female rats. In this study we describe the frequency and specificity of PhIP-induced mutations in the cecum, proximal colon and distal colon of male and female lacI transgenic rats. This is the first report of mutational data from discrete regions of the colon. After 61 days of treatment with 200 p.p.m. PhIP mixed into the diet, PhIP-induced mutant frequencies were elevated 7-fold in the cecum and 14- to 21-fold in the colon of male and female rats compared with untreated controls. PhIP-induced mutant frequencies increased significantly (overall trend, P < 10(-4)) along the length of the colon of both males and females, with cecum < proximal colon < distal colon. A total of 754 PhIP mutants (363 male, 391 female) were sequenced to provide the mutational spectra for each of the three tissue sections from males and females. These mutational spectra consisted predominantly of G:C-->T:A and G:C-->C:G transversions and deletions of G:C base pairs. There were no significant differences between the mutational spectra with respect to sex or position in the colon. Therefore, we surmise that following induction of mutations by PhIP in male and female colons, non-mutagenic factors, possibly hormonal, preferentially influence the formation of tumors in the colon of male rats.

Animals↗
PubMed2001

Evaluation of exposure to airborne bacterial endotoxins and peptidoglycans in selected work environments.

The aim of this study was to assess workers' exposure to endotoxins and peptidoglycans, as well as associations between workers' reported symptoms and the detected bacterial exposures. From the filter samples, biologically-active endotoxins were analysed with the Limulus amebocyte lysate (LAL) assay. The total amount of endotoxins was analysed as 3-hydroxy (OH) fatty acids with a gas chromatography-mass spectrometry (GC-MS) assay, which was also used to assess peptidoglycans as muramic acid. Biologically-active endotoxins related better to the self-reported symptoms than total endotoxins. Specific 3-OH-14:0 fatty acid in the total endotoxin samples associated better with the symptoms than other 3-OH fatty acids. Half of the surveyed 77 workers reported respiratory symptoms, 27% eye symptoms, and 10% fever or shivering. The proportion of workers with respiratory symptoms was greater when the concentration of endotoxins was over 25 ng/m3. These endotoxin levels were occasionally found in the air of most studied occupational environments. The muramic acid concentrations of peptidoglycans were highest (medians over 100 ng/m3) in the garbage-handling plant and in the grain/vegetable storage houses. The LAL assay for endotoxins, as well as the GC-MS assay analysing muramic acid for peptidoglycans or specific 3-OH fatty acids for endotoxins, seem to be suitable methods for evaluating workers' exposure to airborne bacteria.

Adolescent↗
PubMed2000

Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry.

Extractable tannins were analysed by liquid chromatography-electrospray ionisation mass spectrometry in two oak species, North American white oak (Quercus alba) and European red oak (Quercus robur). They mainly included various glucose gallic and ellagic acid esters. The structures were partially determined, and they included grandinin/roburin E, castalagin/vescalagin, gallic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercitrin and ellagic acid.

Chromatography, Liquid↗
PubMed2000

Applicability of homogeneous exposure groups for exposure assessment in the chemical industry.

The purpose of the study was to assess occupational exposure to chemicals, by taking the aspects presented in European standard EN 689 into account, especially with respect to homogeneous exposure groups and their suitability as the basis for exposure assessment. In addition, dermal exposure to chemicals was assessed when appropriate. The industries studied included a plywood factory, a paint factory and a sewage treatment plant of an oil refinery. The workers were classified into homogeneous exposure groups by the persons in charge of occupational health issues in the respective workplaces. The concentrations of the contaminants were measured in workplace air by breathing-zone and stationary sampling, and these approaches were compared. Dermal exposure was measured when applicable. The homogeneity of the grouping was tested with analysis of variance whenever possible. The tasks studied in plywood manufacturing fulfilled the criteria of homogeneous exposure groups for both respiratory and dermal exposure. The group of operators in the sewage treatment plant was highly homogeneous. The complicated organization of the tasks made the use of homogeneous exposure groups (HEG) unsuitable at the paint factory. These findings show that reliable exposure assessment cannot be achieved with a formal standard; instead, comprehensive occupational hygiene evaluation is needed. It should also have a great importance when exposure models are developed.

Chemical Industry↗
PubMed2000

Comparison of tanker drivers' occupational exposures before and after the installation of a vapour recovery system.

The purpose of this study was to compare tanker drivers' occupational exposure level before and after the installation of vapour recovery facilities at 14 service stations. Road tanker drivers are exposed when handling volatile petrol liquid in bulk in the distribution chain. The drivers' exposure was studied during the unloading operation as the bulk petrol flowed into underground storage tanks, displacing vapours in the tank space and causing emission to the environment and the drivers' work area. The exposures were measured again when the dual point Stage I vapour recovery systems were installed for recycling vapours. Short-term measurements were carried out in the drivers' breathing zones by drawing polluted air through a charcoal tube during unloading. The samples were analysed in the laboratory by gas chromatography for C3-C11 aliphatic hydrocarbons, tert-butyl methyl ether (MTBE), tert-amyl methyl ether (MTAE), benzene, toluene and xylene. The road tanker loads delivered consisted of oxygenated and reformulated petrol (E95 and E98 brands), which contained on average 13% oxygenates. Before the installation of the vapour recovery system, the geometric mean (GM) concentration of aliphatic hydrocarbons was 65 mg m-3 (range 6-645 mg m-3) in the drivers' breathing zones. After the installation at the same service stations, the corresponding exposure level was 8.3 mg m-3 (range < 1-79 mg m-3). The GM of the MTBE concentrations was 8.6 mg m-3 (range 1-67 mg m-3) without vapour recovery and 1.5 mg m-3 (range < 0.1-10 mg m-3) with vapour recovery. The differences between the aliphatic hydrocarbons and the MTBE exposure levels during the unloading of the road tankers without and with vapour recovery were statistically significant (p < 0.05).

Air Pollution↗
PubMed2000

Relationship between calf muscle size and strength after achilles rupture repair.

The object was to study the relationships between calf muscle size and strength in 85 patients an average of 3.1 years after repair of achilles tendon rupture. The isokinetic calf muscle strength results were excellent or good for 73% of the patients, whereas calf muscle size was normal in only 30%. The average plantar flexion peak torque per unit muscle cross-sectional area was higher on the injured side than on the uninjured side. The average calf muscle cross-sectional area deficit was 15+/-9% (p<0.001) of that on the unaffected side, while the average plantar flexion peak torque deficit was speed-dependent, being 9+/-18%, 10+/-18 and 2+/-13% of that on the unaffected side at 30, 90, and 240 degrees/sec (p<0.001). The correlation between cross-sectional area and peak torque varied in the range 0.52-0.61 at 30, 90 and 240 degrees/sec (p<0.001).

Achilles Tendon↗
PubMed1999

Assessment of total exposure to phenol-formaldehyde resin glue in plywood manufacturing.

OBJECTIVE: Respiratory and dermal exposure to phenol-formaldehyde resin-glue components used in plywood manufacturing were assessed. METHODS: Formaldehyde and phenol were monitored in the workplace air. Formaldehyde was measured both in the breathing zones of the workers and at stationary sampling sites. Phenol was used as a marker agent for dermal exposure due to its near-nonvolatility at the temperatures occurring during the present study and to its ready absorption through the skin, causing systemic exposure in addition to local skin rashes. Sampling and analytical methods were developed to measure the dermal exposure to phenol. Sampling was accomplished with whole-body dosimetry using Tyvek coveralls and cotton gloves. In addition, a liquid chromatography method was developed for the analysis of phenol from dermal exposure samples. RESULTS: As expected, formaldehyde was noted to be the major compound causing respiratory exposure. When exposure assessment was done on the basis of air samples collected both at stationary sampling sites and in the breathing zones of the workers the agreement between the results obtained was good. The dermal sampling revealed that the workers were exposed to phenol, but the risk for toxic effects was slight due to the low concentrations of urinary phenol. CONCLUSIONS: We conclude that it is possible to use the stationary sampling method for the assessment of respiratory exposure in a plywood factory instead of the usually more complicated breathing-zone sampling. This study also demonstrates the importance of taking dermal exposure into account, at least due to the ability of the resins to cause skin rashes, in assessment of the exposure to chemicals in plywood manufacturing.

Administration, Cutaneous↗
PubMed1998

Dissolution of short and long rockwool and glasswool fibers by macrophages in flowthrough cell culture.

Dissolution of MMVF (man-made vitreous fibers) by macrophages has previously been studied utilizing cell cultures in wells. A new, more dynamic method has been developed to explore the effects of macrophages on MMVF dissolution. In this method, the culture medium flows through a membrane on which the macrophages and fibers are placed. The dissolution of short and long rockwool and glasswool fibers was investigated in the present study by macrophages by assessing the dissolution of Si (silicon), Fe (iron), and Al (aluminium) from the fibers. Dissolution of these elements usually increased as a function of time. Generally, the dissolution of elements from the fibers in the flowthrough culture exceeded that observed with the culture in wells system. The dissolution of glasswool fibers was greater in medium than in cell culture, whereas the opposite was true for rockwool fibers. Dissolution of Si was greater from glasswool than from rockwool fibers, while the opposite was true for Fe and Al. Macrophages that had phagocytized fibers in flowthrough culture contained Si, and there were also precipitations with Si in the samples. The fibers in the flowthrough culture also exhibited surface changes such as breakings, pittings, etching, and peeling. The short rockwool fibers tended to fracture more than short glasswool fibers, while long glasswool fibers were more extensively broken than short glasswool fibers. The results with this new, dynamic, flowthrough culture method with macrophages demonstrate that this method provides valuable information on the abilities of macrophages to dissolve MMVF leading to subsequent morphological changes of fibers.

Aluminum↗
PubMed1998

Validation of computer-mediated open-ended standardized patient assessments.

Quantitative information regarding the development of students' clinical reasoning skills is valuable in assessing third- and fourth-year medical students' clinical knowledge. Standardized patient cases are often used to obtain this quantified information. These cases typically involve a post-patient examination consisting of a series of closed-ended multiple-choice questions. Many medical educators question whether the results from the closed-ended multiple-choice questions truly reflect students' clinical knowledge and reasoning proficiency. Since 1995, the Kirksville College of Osteopathic Medicine (KCOM) has used a computer program, SOAP Note Plus, for standardized patient assessment of students to automate the post-encounter documentation and evaluation. This paper describes the development of the SOAP Note Plus program and a validation study which was conducted to determine the empirical association between the computer-mediated closed-ended and open-ended post-encounter standardized patient assessments. Correlation and GENOVA statistics were used in the analysis of the performance of third-year medical students on the closed-ended and the open-ended assessments following standardized patient encounters and the relationship to their undergraduate GPA, first 2-year medical school GPA and the actual clinical rotation evaluations. The initial results show the positive relationship between the open-ended assessment and the actual clinical rotation evaluations. undergraduate GPA and the first two-years of medical school GPA.

Clinical Competence↗
PubMed1996

Biological monitoring of deltamethrin exposure in greenhouses.

This study examined the possibility of using biological monitoring to assess deltamethrin exposure among greenhouse workers. The synthetic pyrethroid deltamethrin was sprayed in five greenhouses by cold for generators, and the exposure was biologically monitored by analysing the concentration of its metabolite, 3-phenoxybenzoic acid, by a gas chromato-graphic method after derivatization with pentafluorobenzyl bromide. 3-Phenoxybenzoic acid was found in the urine of two of the ten workers studied. The urine concentration of the metabolite varied from 2.4 to 51.7 micrograms/l. These results show that 3-phenoxybenzoic acid is suitable for biological monitoring for the assessment of exposure to deltamethrin.

Adult↗
PubMed1996

Exposure to airborne metals in the manufacture and maintenance of hard metal and stellite blades.

This study evaluated the exposure of Finnish workers to airborne metals. It was conducted in 16 workplaces; 8 tool manufacturing companies (3 of which specialize in the maintenance of hard metal blades) and 8 blade repair shops in the mechanical wood-processing industry. The main emphasis of the study was on exposure in servicing (resharpening), especially involving wet-tip grinding processes. The results show that workers grinding hard metal blades may be exposed to high levels of airborne cobalt even when airborne total dust concentrations are low. The respirable proportion of the total dust was found to be high, and the total dust concentrations correlated well with the cobalt concentrations. Most of the airborne cobalt was water soluble (ionized), but there was also solid particles containing cobalt and other materials in the air of the workplaces. The mean concentration of cobalt in the grinding coolants was high, though it varied considerably. Concentrations of all the other metals measured in the air (tungsten, chromium, cadmium, silver, and nickel) and in the coolants (tungsten and chromium) were low. To reduce workers' exposure to cobalt, it is recommended that grinding machines should be enclosed and equipped with local exhausts. Use of coolants that dissolve less cobalt is also recommended, and the coolants should be changed more often. Brazing should be done in a well-ventilated place, and only cadmium-free materials should be used.

Aerosols↗