Biomedical subjects

H Sigurdsson

Publications and source records attributed to H Sigurdsson.

At least 19 recordsLinked to original sources

PubMed2005

Infestation of Werneckiella equi on Icelandic horses, characteristics of predilection sites and lice dermatitis.

Lice infestations on horses caused by the lice Werneckiella (Damalinia) equi and Haematopinus equi are observed worldwide. In this study, the distribution and clinical manifestations of lice on Icelandic horses were examined. Thirty-eight out of 93 animals (40.86%) were identified as infested with W. equi. Sixty-eight animals (73.12%) presented dermatological lesions associated with lice infestation, while only 32 of these animals presented lice. Six animals had no clinical signs although of being lice-positive, and 19 animals (20.43%) showed neither lice nor clinical manifestations. Lice burdens varied from animal to animal, and clinical manifestations occurred at all levels of infestation. Focal alopecia was the main clinical sign (83.78%) on lice-positive horses, while scaling and crusts occurred in 10.81% and 9.68% of the cases, respectively. Clinical signs present in the head and the neck/mane area were found to be an indication of lice infestation in horses.

Animals↗

PubMed2005

The time pattern of bilateral exudative age-related macular degeneration.

PURPOSE: To study time patterns in bilateral exudative age-related macular degeneration (AMD) and the pattern of drusen before and after the onset of exudative AMD. MATERIAL AND METHODS: Out of 2220 individuals in the Icelandic genetic study of AMD, 151 had bilateral exudative AMD. We searched for previous records in the Icelandic University Retina Unit. For the 65 patients with a fluorescein angiography record of both eyes, we established the time between the onset of disease in each eye. For the 53 patients with colour fundus photographs of the latter eye taken prior to the occurrence of exudative disease, we graded the drusen before and after the onset of exudative AMD in the second eye. RESULTS: The time interval between the onset of exudative AMD in the first and second eyes was 2.5 years (95% CI: 1.8-3.2; n = 65) and the median was 1.8 years. In 82% of cases the second eye was affected within 4 years. Soft drusen in the macula were found in 95% of eyes that later developed exudative disease (n = 53). Soft and hard drusen decreased in number in the central macula following the development of exudative disease. CONCLUSIONS: Bilateral exudative AMD develops within a few years in both eyes. Drusen are less visible following the onset of exudative AMD in the second eye.

Aged↗

PubMed2004

Natural infestation of the chewing lice (Werneckiella equi) on horses and treatment with imidacloprid and phoxim.

Infestation with the chewing louse (Werneckiella (Damalinia) equi) can be found on horses world-wide. Louse infestations, including clinical signs of louse-derived dermatitis, are known from Icelandic horses. A clinical field investigation was conducted in Iceland using horses with natural louse infestations to evaluate the efficacy of imidacloprid in a 10% solution in comparison with phoxim in a 0.05% solution. A total of 27 horses received a single imidacloprid treatment using 16 ml of the 10% solution along the mane and on the dorso-lateral trunk. A further 43 horses were treated twice, 14 days apart, with phoxim, using 2 x 50 ml solution applied along the mane and the dorso-lateral trunk. At the final evaluation on day 28, complete control of the lice was obtained for the imidacloprid treated horses and only a single moribund louse was found on two horses treated with phoxim.

Animals↗

PubMed2001

Risk factors associated with hindlimb lameness and degenerative joint disease in the distal tarsus of Icelandic horses.

The aim of this study was to evaluate potential risk factors associated with hindlimb lameness and radiographic signs of degenerative joint disease (DJD) in the distal tarsus in Icelandic horses. The material consisted of riding horses (n = 420) age 6-12 years sired by 17 selected sires representing all major breeding lines, and of riding horses (n = 194) in the same age range sired by other sires. The examination protocol included the following: interview with owners/trainers, assessment of conformation, motion evaluation and radiographic examination. At the interview, data related to factors outside the horse (environmental variables) and data associated directly with the horse (intrinsic variables) were obtained. Data analysis was performed in 2 steps: screening using bivariate analysis, followed by testing with a multivariate logistic regression model. In the multivariate analysis, the factors of sire, age when broken to saddle and stud show participation were strongly associated with the prevalence of lameness. Height at the croup and ability to perform different gaits were also associated with the prevalence of lameness, but to a lesser degree. The risk factors of age, tarsal angle and birthplace were significantly associated with radiographic signs of DJD in the distal tarsus. Neither the variation in applied training intensity, the use of a professional or amateur trainer nor the temperament or front limb action of the individual horse was significantly associated with the prevalence of hindlimb lameness and/or radiographic signs of DJD in the distal tarsus in the Icelandic horse.

Age Factors↗

PubMed2000

Altered expression of HLA class I antigens in breast cancer: association with prognosis.

Loss of surface expression of class I major histocompatibility antigens is commonly observed in malignant tumors and has been considered one of the mechanisms for escape from cytotoxic T cells. However, natural killer cells kill cells lacking HLA class I antigens. In the present study, we characterized by immunohistochemistry the HLA class I expression of breast carcinomas from 187 patients with TNM stages I and II, diagnosed 1981-1984, using beta(2)-microglobulin as a marker and evaluated the effect on survival with a follow-up of up to 14 years. The largest group (48%) consisted of HLA class I-negative tumors (< or =10% of cells stained), mixed expression (>10% and <80% of cells stained) was seen in 36% and only 15% were classified as HLA class I-positive (> or=80% cells stained). No associations could be established with various clinicopathological parameters, such as tumor size, presence of lymph node metastases, histological grade, expression of hormone receptors, S phase and p53 mutations. There was no effect on recurrence-free survival in the whole group; but among node-negative patients (n = 86), those who had tumors with mixed HLA class I expression had a significantly higher probability of disease recurrence (OR = 3.42, p = 0.014) than patients with either HLA class I-positive or -negative tumors, particularly after more than 5 years. In node-positive patients who received adjuvant therapy, this phenotype was not associated with disease recurrence.

Antigens, Neoplasm↗

PubMed2000

Radiographic and clinical survey of degenerative joint disease in the distal tarsal joints in Icelandic horses.

The prevalence of degenerative joint disease (DJD) in the distal tarsal joints and the relation between radiographic and clinical signs compatible with the disease were estimated in a population of Icelandic horses used for riding. The material consisted of 614 horses age 6-12 years (mean age = 7.9 years). Radiographs with 3 projections of each tarsus were made and a clinical examination, including palpation of the medial aspect of the distal tarsus and motion evaluation of the hindlimbs before and after a flexion test of the tarsus, was performed. Radiographic signs of DJD in the distal tarsal joints were found in 30.3% of the horses and the prevalence was strongly correlated with age. Hindlimb lameness before and after flexion test and palpation abnormalities were significantly associated with the radiographic findings. The lameness was usually mild and, in most cases, detectable only after the flexion test. The prevalence of lameness was not significantly correlated with age. Lameness could not be predicted by details of the radiographic findings.

Age Factors↗

PubMed1998

Mapping loss of heterozygosity at chromosome 13q: loss at 13q12-q13 is associated with breast tumour progression and poor prognosis.

Several chromosome regions exhibit loss of heterozygosity (LOH) in human breast carcinoma and are thought to harbour tumour suppressor genes (TSG). At chromosome 13q, two TSGs have been identified, RB1 at 13q14 and BRCA2 at 13q12-q13. In this study, 139 sporadic breast tumours were analysed with 18 polymorphic microsatellite markers for detailed mapping of LOH at chromosome 13q and evaluation of an association with known progression factors. LOH with at least one marker was observed in 71 (51%) of the tumours analysed. The deletion mapping indicated three LOH target regions, 13q12-q13, 13q14 and 13q31-q34. LOH at chromosome 13q12-q13 was associated with low progesterone receptor content, a high S phase fraction and aneuploidy. Multivariate analysis adjusting for lymph node involvement and S phase fraction showed that patients with tumours exhibiting LOH at 13q12-q13 have a 3-4-fold increased risk of recurrence and death compared with other patients. Our results suggest there are at least three separate LOH target regions at chromosome 13q and inactivation of one or more genes at chromosome 13q12-q13 results in poor prognosis for breast cancer patients.

Aneuploidy↗

PubMed1998

Inherited BRCA2 mutation associated with high grade breast cancer.

Inheritance is believed to play a major role in 5-10% of breast cancer. The breast cancer susceptibility genes BRCA1 and BRCA2 are estimated to account for more than half of these cases. Recent studies have suggested that breast cancers associated with BRCA1 germline mutations are of higher grade than sporadic cases. The purpose of this investigation was to determine if there are significant pathologic and biologic differences between hereditary BRCA2 related breast carcinomas and non-hereditary breast cancers. Forty cases of hereditary breast cancer from families associated with a specific 999del5 BRCA2 mutation were compared with regard to histologic and biologic factors to an age matched control group. Thirty-four patients (85%) had ductal carcinoma, two had lobular carcinoma, and one patient had medullary carcinoma. Compared to the control group, the BRCA2 tumors had less tubule formation (p = 0.02), more nuclear pleomorphism (p = 0.02), and higher mitotic rates (p = 0.002), and were thus of higher histologic grade (p = 0.003). By flow cytometry the BRCA2 tumors also had significantly higher S-phase fractions than the control tumors (p = 0.02). Significant differences in axillary lymph-node involvement or ploidy status were not detected. According to the results of this study, hereditary breast cancers associated with the 999del5 BRCA2 mutation are high grade tumors with a rapid proliferation rate. Other or additional factors than the defining BRCA2 mutation are involved in determining the tumor type.

Adult↗

PubMed1998

Enucleation and evisceration in Iceland 1964-1992. Study in a defined population.

A retrospective study showed that from 1963-1992 200 eyes were enucleated or eviscerated in Iceland. The mean annual age-adjusted incidence per 100,000 population was 2.66, 50% higher for males than females. The mean annual age- and gender-adjusted incidence has decreased; was highest 3.58 per 100,000 for the period 1971-1978, but was 1.76 per 100,000 for the period 1985-1991. The indications were 1) Blind painful eye (92 eyes), 2) Suspicion of malignant neoplasm (49 eyes), 3) Acute trauma (35 eyes), 4) Corneal ulcer (17 eyes), 5) Other (7 eyes). Of blind painful eyes only 12 (6%) were due to neovascular glaucoma. Medical care is self-contained within the country, the incidence for enucleation is decreasing for all categories except malignancy.

Adolescent↗

PubMed1998

Lacrimal sac plugging caused by Aspergillus fumigatus.

Aspergillus fumigatus is a rare cause of canalicular obstruction. We present a case where an aspergillosis plug caused extreme tenderness, epiphoria and discharge from the lacrimal puntum. CT scan showed dilation of the lacrimal sac. Medical treatment did not relieve the symptoms. During a planned DCR the sac was opened before the osteotomy, and found to contain a plug which caused the obstruction. Aspergillus fumigatus was grown from culture. The DCR was abandoned and the patient is symptom free one year after the procedure.

Adult↗

PubMed1998

Basal cell carcinoma of the eyelid. Risk of recurrence according to adequacy of surgical margins.

PURPOSE: To examine all basal cell carcinomas of the eyelid diagnosed in Iceland during a 25-year period, paying special attention to the surgical margins of excision in relation to recurrence. Based on the results a simple, clinically relevant method of classifying the surgical margin is proposed. METHODS: All histologically proven basal cell cancer specimens from eyelids were reviewed retrospectively. The surgical excision margins were classified as radical, marginal or intralesional. RESULTS: Recurrence risk was low when the tumor had a surgical margin described as radical or marginal. The recurrence rate was 38% when the margin was intralesional. CONCLUSION: By assessing the surgical margins by this method, which is easy to apply, better understanding between the pathologist and the surgeon may be achieved.

Adolescent↗

PubMed1997

A comparison of cytogenetic studies and flow cytometry in breast carcinomas.

In this study, we compared genetic instability in 70 breast carcinomas analyzed by two different methods, cytogenetics and flow cytometry. This comparison showed that each method has its strengths and weaknesses. Flow cytometry detected aneuploidy in 60% of cases, but missed most of the cytogenetically near-diploid clones and clones with simple chromosomal changes. Cytogenetics revealed chromosomal abnormalities in 50% of the samples. Simple chromosomal changes and multiploidy were readily detected by this method, but some of the clones with a high DNA index by flow cytometry were missed. The two methods gave corresponding results in the majority of cases (54%). In 17 cases, both methods detected matching abnormal clones (r = 0.93) but the DNA index was higher than predicted by the chromosome numbers. Most of the discrepancies might be explained by tumor heterogeneity and insufficient numbers of cells available for cytogenetic analyses. In seven cases, single-cell abnormalities were found that corresponded to a flow cytometry peak. Multiclonality was present in 25% of aneuploid tumors. No association was found between metaphases in cytogenetic preparations and increased S-phase fraction of the tumors, but aneuploid tumors had a significantly higher proliferation rate. Pooling data from both methods demonstrated that the majority of our samples were aneuploid (74%).

Breast Neoplasms↗

PubMed1997

Detection of orbital implant infection with technetium 99m-labeled leukocytes.

Orbital implant infection is a rare cause of anophthalmic socket pain. Because of the potential danger of infection spreading to nearby structures, it is of paramount importance to diagnose the condition as soon as possible. Scintigraphy is a method for diagnosis of graft infections by radioisotopic imaging of inflammatory sites. We report on a patient with socket pain 3 months after implantation of an acrylic implant. The socket appearance was normal and there were no signs of infection other than culture-positive socket exudation. Three consecutive computed tomography scans revealed no abnormalities. 99mTc leukocyte scintigraphy revealed white blood cell accumulation at the implantation site. The implant was removed and cultured. This produced Staphylococcus epidermidis and R. equii. A parenteral antibiotic treatment was instituted with subsequent improvement of symptoms. Four months later, after negative scintigraphy, a hydroxyapatite implant was inserted, demonstrating full vascularization on a bone scan after 2 months. Two months later, the patient developed the previous symptoms, with all of the former findings, including positive scintigraphy. The implant was removed, revealing a microabscess on the anterior aspect, producing S. epidermidis on culture. We conclude that scintigraphy using 99mTc-labeled leukocytes is a useful technique in diagnosing low-grade orbital infection.

Acrylic Resins↗

PubMed1996

TP53 mutation analyses on breast carcinomas: a study of paraffin-embedded archival material.

The aim of this investigation was to examine the possibility of analysing TP53 mutations in archival paraffin-embedded material with the constant denaturant gel electrophoresis (CDGE) method. We extracted DNA from 193 archival primary breast carcinoma samples, diagnosed in 1981-83; further analysis was possible for 186 of these. TP53 mutations in exons 5-8 were detected with CDGE in 30 samples (16.1%) and 17 of these mutations were confirmed by sequencing. Immunohistochemistry demonstrated TP53 nuclear accumulation in 58 tumours (31%). A strong association between the presence of TP53 mutations and TP53 immunostaining was observed (P < 0.001). Our mutation and immunohistochemistry results are in agreement with other findings based on fresh tumour tissue. TP53 abnormalities were significantly related to high S-phase fraction, low oestrogen receptor (ER) content and high tumour grade. Survival of patients with TP53 abnormalities, in the group as a whole, did not differ from patients with normal TP53. Our study did, however, show that patients with abnormal TP53 had a significantly shorter post-recurrence survival (P = 0.005) than patients with normal TP53.

Amino Acid Sequence↗

PubMed1995

Loss of heterozygosity on chromosome 9 in human breast cancer: association with clinical variables and genetic changes at other chromosome regions.

Primary breast tumors were tested for loss of heterozygosity (LOH), on chromosome 9p with microsatellite markers restricted to a 28 cM region including the MTS1 gene. LOH was found with at least 1 marker in 38% of the 201 cases analyzed. A high frequency of deletions was detected at the 9p23-p21 region, indicating a tumor suppressor gene(s) important for breast cancer tumorigenesis. Tumors with and without LOH on 9p were compared with respect to clinico-pathological factors using chi 2 analysis. Tumors with 9p LOH were significantly associated with high S-phase status and aneuploidy, but not with type, node status, estrogen and progesterone receptor content or age of the patients at diagnosis. Survival analysis showed that LOH at 9p did not significantly affect the survival rate of breast cancer patients. Our results indicate that the aberrations on 9p detected in this study are not of independent prognostic value. A significant association was found between LOH at 9p and LOH at chromosomal arms 3p and 6q, which is an additional contribution toward understanding the genetic events in breast tumor pathogenesis.

Alleles↗

PubMed1995

Recurrence-free survival in breast cancer improved by adjuvant tamoxifen--especially for progesterone receptor positive tumors with a high proliferation.

Although the beneficial effect on breast cancer of adjuvant tamoxifen (TAM) is well established, in the series studied by our group this effect seems to have been restricted to patients with steroid receptor (especially progesterone receptor (PgR)) positive tumors. However, as some patients with PgR-positive tumors manifested recurrence despite adjuvant TAM treatment, the question arose whether some other biological factor(s) could be used to identify these non-responding cases. The level of the S-phase fraction (SPF), as measured by flow cytometry, has been shown to be a useful prognostic marker, prognosis being better in cases where the SPF is low than in those where it is high. The aim of the present study was to relate the prognosis after adjuvant TAM to SPF among patients with PgR-positive tumors. In the PgR-positive group as a whole, the effect of TAM on prognosis was more pronounced in the high SPF group than in the low SPF group (p = 0.005) the respective decrease in 3 year recurrence rate was from 19 to 43% and from 17 to 9%. Multivariate analysis of the data for the TAM-treated group showed the level of PgR concentration (low positive vs. high positive), lymph node status, and tumor size to be independent predictive factors, but not the level of SPF (i.e. high vs. low). By contrast, among patients not treated with TAM, the SPF was a strong independent prognostic factor. To sum up, SPF was a strong independent predictor of outcome only for patients receiving no systemic adjuvant therapy, but not in patients receiving adjuvant TAM. Patients with PgR-positive and high S-phase tumors derived more benefit from TAM than patients with PgR-positive and low SPF tumors.

Adult↗

PubMed1994

ERBB2 amplification is associated with tamoxifen resistance in steroid-receptor positive breast cancer.

Amplification and overexpression of the ERBB2 (HER-2/neu) oncogene has been implicated as contributing to the development of human breast cancer, and as a predictor of poor survival. In the present non-randomized study of 871 primary invasive breast tumours, ERBB2 activation was significantly correlated to a shorter disease-free and overall survival in the subgroup of patients receiving adjuvant tamoxifen therapy, but not in the untreated group. Further subcategorization demonstrated the relationship to poor prognosis to be confined to lymph node positive and steroid receptor-positive tumours. We suggest that steroid receptor and ERBB2-positive breast tumours are resistant to tamoxifen therapy and, supported by experimental evidence showing an oestrogen receptor dependent up-regulation of ERBB2 expression upon tamoxifen administration, possibly even growth stimulated by the drug.

Breast Neoplasms↗

PubMed1994

Cathepsin D, both a prognostic factor and a predictive factor for the effect of adjuvant tamoxifen in breast cancer. South Sweden Breast Cancer Group.

Cathepsin D is a lysosomal protease implicated in cancer metastasis. Its concentration in breast tumours has also been shown to be of prognostic importance, although to what extent this is subject to lymph node status, the use of adjuvant therapy and menopausal status has not been clearly evaluated. At a cut-off level of 45 pmol/mg protein (61% of the 623 samples were classified as high cathepsin D tumours; immunoradiometric assay), we found cathepsin D to be of prognostic importance only among breast cancer patients with lymph node-positive (N+) disease not treated with adjuvant tamoxifen. When the series was stratified according to cathepsin D content of their tumours, progesterone receptor (PgR) status and lymph node involvement, adjuvant tamoxifen was found to have a significant beneficial effect only among patients with N+ and PgR-positive breast cancer whose tumours had a high cathepsin D content.

Aged↗