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Biomedical subjects

J Larsen

Publications and source records attributed to J Larsen.

At least 91 records · Page 5Linked to original sources
PubMed1993

Transformation of chicken bone marrow cells by the v-ski oncogene.

The effect of the v-ski oncogene on the transformation of chicken hematopoietic cells was examined. In initial experiments viruses encoding the v-ski oncoprotein did not transform chicken bone marrow cells. However, whereas viruses encoding the ts-v-sea oncoprotein transform solely erythroid cells, viruses encoding both the v-ski and the ts-v-sea oncogenes were found capable of transforming myeloid cells from the monocytic and/or granulocytic lineages in addition to erythroid cells. Analysis of cell clones transformed by the v-ski/ts-v-sea virus identified one clone that no longer expressed the v-sea protein, indicating that this protein was necessary for the initiation but not the maintenance of transformation. Subsequent experiments testing the effects of various growth factors on transformation of bone marrow cells by the v-ski oncogene product alone identified the avian c-kit ligand (stem cell factor; SCF) as being able to co-operate with the v-ski protein to cause transformation of chicken hematopoietic cells of both myeloid and erythroid lineages.

Animals↗
PubMed1993

Transcutaneous devices for the measurements of pO2 and pCO2. State-of-the-art, especially emphasizing a pCO2 sensor based on a solid-state glass pH sensor.

In treating critically ill neonates it is vital to ensure optimal delivery oxygen to the tissue and simultaneously make sure that carbon dioxide is removed from the tissue. The continuous non-invasive transcutaneous measurements of pO2 and pCO2 make it possible to detect sudden changes in pO2 and pCO2 immediately, so prompt corrective action can be implemented to ensure optimal neonatal patient care. A new combined solid state transcutaneous sensor for measurement of pO2 and pCO2 is described in the paper. The pO2 part of the sensor has been redesigned and its performance improved to ensure more reliable pO2 readings during in vivo measurements. The pCO2 part of the sensor has been completely redesigned. The application of a new solid state technology in the production of the pCO2 combined with the use of a new, reinforced, composite pH sensitive glass membrane, has resulted in an extremely robust and reliable pCO2 sensor.

Blood Gas Monitoring, Transcutaneous↗
PubMed1993

Functional outcome of below-knee amputation in peripheral vascular insufficiency. A multicenter review.

A retrospective functional outcome study was performed on 299 patients treated with below-knee amputations for peripheral vascular disease during a three-year period in six Veterans Administration special amputee centers. Sixty-one percent of the patients were diabetic, and 25% were previously unilateral amputees. Surgery was performed with a long posterior flap in 92.3%, sagittal flaps in 20%, and guillotine open technique in 5.7%. Wound management was accomplished with rigid plaster dressings in 75.3%, pneumatic compression dressing in 14%, and soft dressings in 10.7%. At follow-up evaluation one to two years later, 36.1% had died. Thirteen percent suffered wound complications, with 6.7% requiring revision to a more proximal amputation level. Eighty-seven percent of community ambulators maintained their ambulatory status. A comparable percentage maintained their ability to walk with a prosthesis.

Amputation, Surgical↗
PubMed1992

[HIV testing and HIV surveillance of a venereological clientele in Denmark].

The object of this investigation was to evaluate the suitability of unlinked anonymous HIV screening of persons visiting one of eight out of the nine Danish clinics for venereal diseases in the national HIV surveillance. Data were collected during the period July 1, 1990-March 31, 1991 and included: gender, sexual orientation, history of intravenous drug use (IVDU), syphilis testing and HIV testing. A total of 7,455 persons participated of whom 75% were tested for HIV antibodies. The HIV test activity was significantly higher among male IVDUs than homo/bisexuals, and higher among female IVDUs than heterosexuals. The overall HIV prevalence among tested individuals was 0.6%, ranging from 0.1% among heterosexual women to 5.3% among female IVDUs. A total of 81% were tested for syphilis with an overall HIV prevalence of at least 1.1%, ranging from 0.2% among heterosexuals to 9.3% among homo/bisexual men. Since the non-participation is great and the venereological clientele is very heterogeneous, using blood taken for syphilis serology from this group for unlinked anonymous HIV screening, would not be particularly important as a supplement to the Danish HIV surveillance.

Denmark↗
PubMed1992

[Screening for uterine cervix cancer in Storstrøm, Vestsjaelland and Bornholm counties during 1979-1989].

We studied the use of Pap smears in three counties in Denmark, where the screening activity has been organized in different ways. The county of Storstrøm had an organized screening programme in 1979-82. Women aged 30-50 years were invited personally, and 91% participated. The same response rate is seen in the county of Bornholm today, where women aged 25-54 years are invited. No invitations are sent in the counties of Storstøm and Vestsjaelland today, and only 66%-69% of the 30-50 year old women are screened. The Danish National Board of Health recommends commencement of screening at the age of 23 years. However, 53%-57% of the women aged 15-22 years are screened in Storstrøm and Vestsjaelland counties today. The percentages of women screened in the older age groups are, on the other hand, low. Only 10%-17% of women aged 60-75 years were screened in 1985-89. The Danish National Board of Health recommends that women aged 23-75 years should be screened once every third year and that positive, atypical and unqualified smears should be followed-up. The county of Bornholm has an organized screening programme, but 21% of the Pap smears are nevertheless used outside the national recommendations. The county of Vestsjaelland has no organized screening programme and 42% of the Pap smear are used outside the national recommendations. It would be possible to screen a considerably higher percentage of the women aged 23-75 years if the screening activity was well organized.

Adult↗
PubMed1992

Detection of HBV DNA by PCR in serum from an HBsAg negative blood donor implicated in cases of post-transfusion hepatitis B.

An HBsAg negative blood donor, and three of her recipients, who developed HBsAg positive post-transfusion hepatitis B, were all positive for serum HBV DNA by polymerase chain reaction (PCR), and by subtype discriminating PCR were found to harbour HBV specifying ayw. Thus HBV specifying ayw. Thus HBV DNA may be detected and sub-typed by PCR in infectious HBsAg negative individuals.

Base Sequence↗
PubMed1992

Second-generation anti-HCV tests predict infectivity.

Twenty-four blood donors found positive for the first-generation hepatitis C antibody (anti-HCV) test (Ortho EIA-I) and 88 of their recipients over the period from 1972 to 1990 were retrospectively investigated with different first- and second-generation anti-HCV tests. The aim of the study was to identify the infective donors and to evaluate the tests. Seven donors, who probably were infective carriers of HCV, were also second-generation test (EIA-II) positive, compared to only 3 out of 17 noninfective donors. Among the infected recipients, 14 out of 29 (48%) were positive for the second-generation test only. The second-generation test identified the infective donors in our study and was more sensitive than the first-generation test. We therefore recommend that blood donors are screened with EIA-II. Positive test results should be confirmed by the recombinant immunoblot assay (RIBA-II), and persons with positive or not conclusive RIBA-II should not be accepted as blood donors.

Blood↗
PubMed1992

Low to moderate intensity endurance training in healthy older adults: physiological responses after four months.

OBJECTIVE: To determine the physiological adaptations in previously sedentary healthy older men and women (mean age = 68) to a 16-week low-to-moderate-intensity exercise program. DESIGN: Randomized, controlled trial. SETTING: An exercise facility and testing laboratory in a gerontological research institute. PARTICIPANTS: Two-hundred forty-seven community-dwelling older persons free of significant cardiovascular, pulmonary, or uncontrolled metabolic disease, anemia, electrolyte abnormality, resting BP of 165/90 or greater, or chronic disease affecting the ability to exercise on a bicycle. INTERVENTION: Subjects were randomly assigned to either an exercise (n = 166) or attention control group (n = 81). Exercisers trained thrice weekly for 40 minutes on a cycle ergometer (5-minute warm up, 30 minutes at training heart rate (THR), 5-minute cool down). THR was set at 70% of peak heart rate attained on a maximal exercise test (mean = 115 +/- 15). Control subjects attended weekly group talks. Testing took place before and after the program. RESULTS: Peak attained oxygen uptake (VO2max) increased 8.5% in exercisers and decreased slightly in controls (p less than .001) and oxygen uptake at ventilatory threshold (VeT VO2) increased by 3.5% in exercisers and decreased by 3% in controls (p less than .001). This pattern of a greater increase in VO2max than VeT VO2 is different from that seen in young and middle-aged subjects. CONCLUSION: This study demonstrated that a large scale training program is feasible for healthy older people, that physiologic improvements can be measured after 16 weeks of low-to-moderate-intensity training, and that mechanisms of adaptation to exercise may be different in elderly subjects from those in younger ones.

Adaptation, Physiological↗
PubMed1992

The ELAM-1 ligand sialosyl-Le(X) is present on Langerhans cells isolated from stratified epithelium.

In this study we show the expression of the newly identified carbohydrate ligand, sialosyl-Le(X) on Langerhans cells. The receptor for sialosyl-Le(X) is the endothelial leukocyte adhesion molecule-1 (ELAM-1) present on activated endothelial cells. Using flow cytometry, Langerhans cells were selected due to positivity for an antibody against CD1a and low orthogonal light scatter. The CD1a antigen stained by the OKT6 antibody is considered a maturational marker of Langerhans cells in agreement with the specific labeling of dendritic cells in the epithelium only. Double immunostaining (OKT6/anti-sialosyl-Le(X)) using flow cytometry and immunohistochemistry demonstrated that almost all OKT6-positive cells in normal stratified epithelium expressed sialosyl-Le(X). Conversely, by immunohistochemistry of oral epithelium with acute inflammation, additional dendritic cells negative for OKT6 were found to express sialosyl-Le(X). In addition, sialosyl-Le(X)-positive but not OKT6-positive dendritic cells were found in the submucosa. These findings indicate that the carbohydrate antigen sialosyl-Le(X) is expressed earlier than the CD1a antigen in the maturation of the Langerhans cell lineage. Future studies should aim at investigating the importance of adhesion between sialosyl Le(X) and ELAM-1 in epithelial recruitment of Langerhans cells.

Antigens, CD↗
PubMed1992

The v-ski oncogene cooperates with the v-sea oncogene in erythroid transformation by blocking erythroid differentiation.

The avian retrovirus oncogene v-ski was analysed for its ability to alter the differentiation program of erythroid cells and to cooperate with tyrosine kinase oncogenes in leukemogenesis. For this, a retrovirus combining v-ski with a temperature-sensitive version of the v-sea oncogene was constructed. In transformed erythroblasts, v-ski disturbed the concerted expression of several erythrocyte genes, leading to an abnormal erythroblast phenotype. Expression levels of hemoglobin and erythrocyte anion transporter (band 3) were elevated, while expression of the erythroid-specific histone H5 was strongly suppressed. v-ski could also be shown to repress or severely retard the temperature-induced erythroid differentiation of v-ski/ts-v-sea-transformed cells. The undifferentiated cells had an abnormal erythroblast or early reticulocyte phenotype characterized by unusually low levels of histone H5. In chicks, the v-ski/ts-v-sea virus displayed enhanced leukemogenicity compared with viruses containing just the single oncogenes. Thus, v-ski cooperates with tyrosine kinase oncogenes in a similar fashion to the v-erbA oncogene, however the pattern of genes affected by these two oncogenes is different.

Animals↗
PubMed1991

[Tennis injuries--incidence and pattern].

At the conclusion of the tennis season in autumn 1987, a questionnaire investigation was performed among all of the registered members of a typical Danish club of average size. The object of the investigation was to review the frequency and pattern of injuries in a club of this type. A total of 160 replies which could be employed were received (percentage replies 53.3). The replies were representative as regards age and sex. The frequency of injuries was calculated to be 5.0 injuries/1,000 playing hours. On account of the limited size of the material, calculations of significance were not performed but the results do not suggest that the incidence of injuries is greater in men compared with women or in the age group 19-24 years compared with other age groups. On the other hand, the risk of injury appears to be greater for competitive players than for those who played tennis just for the exercise. The most frequent single injury was "tennis elbow" (18.2%, all in men). 66.6% of the injuries were due to overuse. It is suggested that prophylaxis should be intensified where competitive players and aspiring competitive players are concerned, viz, among the youngest players.

Adult↗
PubMed1991

[Itching in the external ear--a side effect of ear plugs].

The object of this investigation was to assess the frequency of itching in the external auditory meatus in individuals who use hearing aid ear plugs (OP) and, simultaneously, to assess the cause of the itching. Seventy-six of the patients examined consecutively in the audiological department (ages 34-89 years) were questioned about itching and were submitted to an objective ear, nose and throat examination, audiometry and culturing from the external meatus for bacterial and fungal growth. In 20 patients, patch tests were made for allergic reactions from which the ear plugs were made (heat polymerized methyl methacrylate). None of the 20 patients had become sensitized. Itching in the external auditory meatus was found to be a side effect of employment of ear plugs with an incidence of 39% as opposed to only seven in ears without ear plugs (p less than 0.05). The incidence of itching was not reduced in ears with a ventilation channel in the ear plug. In 38% of the itching ears no objective changes were observed and, in the remaining cases, the changes were frequently limited. Potentially pathological bacterial growth was found to be significantly more in ears with ear plugs (1- greater than 16%, p less than 0.05) and in itching ears (4- greater than 24%, p less than 0.05). In ears with potentially pathogenic bacteria, objective changes were nearly always found. In the vast majority of cases, the potentially pathogenic bacteria were Gram-negative, corresponding to the findings in external otitis in the tropics and mixed infections with fungi were frequently present.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Human papillomavirus--(HPV)/balanoposthitis--a new disease?].

Two cases of symptom-producing balanoposthitis associated with Human papillomavirus infection are described. These patients had spotty, macular, erythematous rash on the glans penis and prepuce. The symptoms and objective findings resemble those of Candida infection but the diagnosis can be established by histological examination of biopsy from the acetowhite elements.

Adult↗
PubMed1991

[Viral hepatitis and blood transfusion].

Our findings show that hepatitis B-virus was transmitted by blood from two hepatitis B-surface-antigen (HBsAg)-negative but hepatitis B-coreantibody (anti-HBc)-positive donors. Blood donors and recipients were also tested for antibodies against the recently identified hepatitis C-virus (HCV). We found that two anti-HCV-positive donors with no known history of clinical hepatitis were chronic, infective carriers of HCV. The prevalence of anti-HCV in our blood donor population was 0.47% and ALT and anti-HBc testing was of no help for tracing the anti-HCV positives. We recommend that, in addition to HBsAg screening at each donation, donors are tested for anti-HBc and anti-HCV once. Individuals with a history of parenteral virus hepatitis should not be accepted as blood donors.

Blood Donors↗
PubMed1991

Infective, chronic carriers of hepatitis C virus among blood donors with no history of clinical hepatitis.

We investigated the infectivity of three hepatitis C virus antibody (anti-HCV) positive blood donors with either hepatitis B core antibodies (anti-HBc) (Nos 1 and 2) or raised alanine aminotransferase (ALT) (No. 3). The 57 recipients of blood products from these donors during the period 1971-1990 were identified and the living 23 were tested for anti-HCV. Among these, 11 out of 14 (78%) recipients from Nos 1 and 2, and 1 out of 9 (11%) recipients from No. 3 were anti-HCV positive. The former donors had high titres of anti-C100-3 and high rating scores in the HCV recombinant immunoblot assay (RIBA). They were evidently infective, chronic carriers of HCV but had no clinical signs or medical history of hepatitis. The latter donor had low titres of anti-C100-3 and a low RIBA rating score. She had clinical signs of chronic hepatitis and persistently elevated ALT, but only one of her recipients was anti-HCV positive.

Blood Donors↗