Biomedical subjects

M Andersson

Publications and source records attributed to M Andersson.

512 records · Page 29Linked to original sources

PubMedDate not supplied

Allergen-induced specific and non-specific nasal reactions. Reciprocal relationship and inhibition by topical glucocorticosteroids.

The correlation between allergen-induced specific and non-specific (histamine) nasal reactions was studied, especially as regards topical glucocorticosteroid effects on the non-specific reactions. Thirteen patients with strictly seasonal allergic rhinitis participated. A nasal challenge with histamine and three increasing doses of allergen was performed on the first day. The patients were rechallenged 24 h later with the same histamine dose and the lowest allergen dose from the previous day. The same 2-day challenge was also performed after pretreatment for one week with budesonide in 8 of these patients. Symptom scores were recorded. The N-alpha-tosyl-L-arginine-methyl-esterase (TAME esterase) activity in nasal lavages was determined. The nasal symptoms and the TAME-esterase activity increased at rechallenge for both histamine and allergen, compared with the initial challenge. The mean ( +/- SE) composite nasal symptom score after histamine increased from 3.5 +/- 0.49 to 4.9 +/- 0.35 (p less than 0.01) and after allergen from 1.62 +/- 0.3 to 3.2 +/- 0.5 (p less than 0.01) at rechallenge. Similar increases were recorded for the TAME-esterase activity. A close correlation between the allergen-induced increase in specific (allergen) and non-specific (histamine) reactivity was found (r = 0.7, p less than 0.01, composite nasal symptom score). Treatment with topical glucocorticosteroids abolished the allergen-induced increase in both specific (p less than 0.001) and non-specific (histamine) (p less than 0.01) nasal reactivity.

Administration, Topical↗

PubMedDate not supplied

A longitudinal clinical study of Procera ceramic-veneered titanium copings.

PURPOSE: The purpose of the present paper was to study the long-term clinical results with ceramic-veneered Procera titanium copings. MATERIALS AND METHODS: A total of 44 titanium copings (fabricated for 22 patients) veneered with a low-fusing ceramic were followed for 60 to 78 months. The clinical examinations were performed by licensed specialists in prosthetic dentistry. The crowns were rated according to the California Dental Association system. In addition, Bleeding Index and Margin Index were also evaluated. RESULTS: In 3 crowns ceramic fractures necessitated their replacement. Two crowns had to be replaced because of caries. The ratings for surface and color had changed markedly, from excellent to acceptable. Regarding anatomic form, with the exception of the 3 fractured ceramic crowns, there were no obvious changes. The margin integrity, aside from the 2 crowned teeth with caries, was recorded as satisfactory (excellent or acceptable) for all other crowns; in fact, a large majority were rated excellent. Regarding Bleeding Index, there were no differences between crowned teeth and control teeth. Changes in Margin Index showed that the gingiva of the crowned teeth had retracted. CONCLUSION: Of the various clinical factors evaluated, only surface and color-related to the low-fusing ceramic used for veneering-showed any obvious change during the follow-up period. Otherwise the veneered titanium copings had, in general, performed well.

Adult↗

PubMedDate not supplied

On a new method to assess the accuracy of a CAD program.

PURPOSE: This study was initiated with the purpose of developing and evaluating a system for measuring the magnitude of the variation between a computer-aided design (CAD) object created on the computer screen and a replicated object produced by computer-aided manufacturing (CAM). MATERIALS AND METHODS: Controlled geometric forms, a square and a cone, were designed in a CAD program, and measuring distances were selected. The CAD data were transmitted to CAM data, and objects were produced. The CAD/CAM process was the Procera system, and the holder system permitted the objects to be ground into cross sections, similar to the visualization in the CAD program. Five objects of each shape were produced and measured by two operators two times. Three operators measured one of the objects 30 times. RESULTS: Observed values were greater than the true value. For all objects, the systematic error was at most 15.5 microns. Interoperator difference was small. The variation because of measurement error was greater for the square object compared to the cone. However, the variation because of object was higher for the cone object than for the square. The total standard deviation was 7.7 microns. Thus, the total random error caused by object variation and measurement error was in approximately 95% of all measurements less than 15 microns. CONCLUSION: There are no differences in the measurement data derived from this method and actual measurement data from an object created by the computer-aided dental design program. The method has high validity and reliability, i.e., high accuracy.

Analysis of Variance↗

PubMedDate not supplied

Collagen induced arthritis: an experimental model for rheumatoid arthritis with involvement of both DTH and immune complex mediated mechanisms.

The type II collagen induced arthritis animal model (CIA) provides opportunities to study the nature of autoimmune reactions leading to arthritis and is also a useful model for rheumatoid arthritis (RA). Thus, in similarity with RA, the CIA when induced with autologous type II collagen, shows a chronic and progressive disease course. The susceptibility to both RA and CIA are correlated to the expression of certain MHC class II allotype genes. In both diseases autoantibodies to type II collagen and rheumatoid factors are produced. Immunohistopathology of affected joints show in both diseases a dominance of activated macrophages/fibroblasts with a significant infiltration of activated T cells. We suggest here that both RA and CIA are dependent on a synergy between delayed type hypersensitivity and immune complex mediated inflammatory mechanisms and that CIA could provide a tool for studies of immunospecific reactions leading to arthritis.

Animals↗

PubMedDate not supplied

A comparison of the marginal and internal adaptation of titanium and gold-platinum-palladium metal ceramic crowns.

The marginal and internal adaptation of metal ceramic crowns fabricated by electrical discharge machining and conventional metal ceramic alloys were compared. The crowns were cemented using zinc phosphate cement, embedded in epoxy resin, and sectioned in two planes: diagonal and buccolingual. The crowns were then measured at nine sites. The results showed that there were no statistical differences between the external marginal opening of the titanium and the gold-platinum-palladium crowns. The overall marginal discrepancies for the restorations in this study were 61 microns (+/- 34 microns) for the titanium metal ceramic crowns and 47 microns (+/- 17 microns) for the gold-platinum-palladium metal ceramic crowns.

Analysis of Variance↗

PubMedDate not supplied

Titanium copings veneered with Procera ceramics: a longitudinal clinical study.

In 1989, 47 titanium copings veneered with a low-fusing ceramic were fabricated for 24 patients. Forty-four crowns could be examined after a period varying between 26 and 30 months. It was found that the bulk ceramic of two crowns had fractured. California Dental Association ratings for "Surface and Color" had changed markedly from the "Excellent" to the "Acceptable" level, and for "Anatomic Form" there was a small shift from the "Excellent" to the "Acceptable" level. The factor of "Margin Integrity" was recorded as "satisfactory" for all crowns and a large majority were rated "Excellent."

Adult↗

PubMedDate not supplied

Mutations in the tumor suppressor gene p53 in human liver cancer induced by alpha-particles.

The p53 tumor suppressor gene is mutated in varying fractions of almost all tumor types studied. The rate of mutations and the mutational spectrum in some tumors are specific for environmental mutagens assumed to be involved in the carcinogenic process. Thus, hepatocellular carcinomas supposedly induced by aflatoxin exposure often contain a specific point mutation in codon 249, and in lung cancers of miners with heavy radon exposure, another specific point mutation in codon 249 suggestive of an alpha-particle-specific mutation has been shown. The interpretation of studies linking the mutational spectrum with specific environmental exposures is complicated by the multifactorial or unknown genesis of most tumors. However, people given injections of the X-ray contrast medium Thorotrast (Th) in the past have experienced an enormous risk of liver tumors, and virtually all of these are supposedly induced by alpha-particles from the decay of 232Th. The examination of these tumors may provide evidence as to whether specific p53 point mutations are relevant in alpha-particle carcinogenesis. Therefore, we collected paraffin-embedded, formalin-fixed archival tissues from 18 hepatocellular carcinomas, 9 cholangiocarcinomas, and 9 hepatic angiosarcomas from Thorotrast-exposed patients. The tissues were analyzed for p53 protein expression by immunohistochemical staining by using the mAb DO-7 and for mutations of exons 5-8 by PCR and constant denaturant gel electrophoresis. G --> T transversions of the third base of codon 249 of the p53 gene were specifically screened for by restriction enzymes. No high score for p53 protein expression (i.e., positive staining of >20% of examined cells) was observed; lower scores were seen in 5 of 18 (28%) hepatocellular carcinomas, 1 of 9 (11%) cholangiocarcinomas, and 0 of 8 (0%) hepatic angiosarcomas. Only one p53 mutation, a heterozygous T --> G transversion of the first base codon 176, occurred in a hepatocellular carcinoma. The rate of p53 point mutations in alpha-particle-induced liver tumors seems to be lower than in European hepatocellular carcinomas in general. The study does not exclude the possibility that alpha-particle carcinogenesis may involve inactivation of p53 by gross deletions of the gene, but it speaks against the proposed specificity of point mutations of codon 249 in cancer supposedly induced by alpha-particles from radon progeny.

Adolescent↗

PubMedDate not supplied

Serum protein electrophoresis as a prognostic marker of chronic liver disease in dogs.

In a previous study in dogs with chronic liver disease it was found that a combination of clinical features and laboratory findings was useful in differentiating liver diseases but could not be used to evaluate a dog's prognosis. When an electrophoretic analysis of the serum proteins was included, marked decreases in the concentrations of albumin and the alpha-globulins alpha-1-antitrypsin and haptoglobin were observed in terminal liver cirrhosis, indicating impaired liver function. However, low albumin concentrations, together with normal or increased concentrations of alpha-1-antitrypsin and haptoglobin, were observed in dogs which, although severely depressed when examined, often recovered and survived for a year or more.

Alpha-Globulins↗