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Biomedical subjects

M W Bentzon

Publications and source records attributed to M W Bentzon.

At least 91 records · Page 5Linked to original sources
PubMed1981

Statistical evaluation of the lymphocyte proliferation assay with non-stimulated cultures.

A micromethod for the lymphoproliferative assay has been evaluated statistically with non-stimulated human lymphocyte combinations. Different variance components were estimated by means of a hierarchical analysis of variance. Instead of using an arbitrary value for a significant difference between stimulated and non-stimulated cultures, the value can be calculated on the basis of the components of variance in the experimental design. The method disclosed systematic differences between the values of control cultures depending on the lymphocyte combinations and groups of persons examined, which underlines that every experiment should always contain non-stimulated cultures. Further, cell-cell cooperation and differences in spontaneous DNA synthesis within individual lymphocyte populations could be demonstrated.

Analysis of Variance↗
PubMed1981

Loss of Treponema pallidum during incubation in Nelson's survival medium with or without serum added.

Treponema pallidum organisms suspended in equal parts of Nelson's survival medium alone and with addition of various sera were counted in 5 microliters samples before and after 18 hours' anaerobic incubation at 35 degrees C. Samples in which the treponemes were not Poisson-distributed were excluded from the study. A loss of greater than 30% occurred in 230 out of 391 samples. The disappearance of treponemes did not seem to be caused by treponemal agglutination during incubation. There was no adherence of treponemes to the formed elements remaining in the suspension. The loss was not dependent on the concentration of syphilitic serum, nor was it influenced by the presence of immobilizing antibody in the serum. Lack of rigorous anaerobiosis during the manipulations did not influence the treponemal loss. The loss was independent of the density of the treponemal suspensions which did not contain unheated guinea-pig serum (GPS). The relative frequency of the loss exceeding 30% was highest in suspensions containing unheated GPS. However, the extent of loss in individual samples was haphazardly distributed among suspensions of all the compositions examined. The loss of treponemes seems to depend on at least two factors: a) a factor which is eluted together with the treponemes from the syphilitic orchitis and b) the presence of active guinea-pig complement. It is conjectured that the complement is non-immunologically activated and acts through the alternative pathway.

Agglutination↗
PubMed1981

Lung disease caused by Mycobacterium avium/Mycobacterium intracellulare. An analysis of Danish patients during the period 1962-1976.

The present work is a retrospective study in which the case histories of 37 Danish patients with lung infections caused by M. avium/M. intracellulare are analysed. The result of the chemotherapy used, in some cases combined with surgery, was not satisfactory, since the infection became inactive in 11 patients only. One further patient became negative spontaneously. Prognosis studies for various groups of patients were made by statistical analysis of the collective material. The analysis revealed that co-existing lung disease, dyspnoea on admittance and three other features showed positive mutual correlation, and that the two first-named features were significant prognostic criteria. It is proposed that patients without these features should form a separate group with good prognosis, in which less intensive chemotherapy can be employed, i.e. with the three drugs INH, RMP and EMB. Continuation of this treatment beyond 4 months must depend on the bacteriological response and the clinical condition. For the remaining patients, multidrug therapy (with five drugs) is recommended as soon as the diagnosis is established.

Adult↗
PubMed1980

In vitro comparison of gentamicin and netilmicin including a regression line for netilmicin.

The results of two different in vitro investigations are presented: a comparison between gentamicin and netilmicin and a presentation of a regression line for netilmicin. The first investigation comprises 335 bacterial strains. The method used is a plate dilution technique and the susceptibility of the strains is given as IC50 values, i.e. 50% inhibiting concentrations. The conclusion of the study is that netilmicin offers no advantage over gentamicin. In the second investigation a regression line is presented giving the relation between IC50 values for netilmicin and the size of the inhibition zone, based upon 109 bacterial strains. For the disc diffusion method a 20-hour prediffusion technique is used. The disc content is 15 micrograms netilmicin base. The results are discussed and a grouping as to susceptibility is proposed based on the IC50 values found and the blood level obtained after scheduled dose of netilmicin.

Dose-Response Relationship, Drug↗
PubMed1979

Quantitative microbiological assay of thiomersal using agar diffusion from paper discs.

A quantitative assay method for determination of thiomersal in biological products is described and evaluated. A microbiological method using agar diffusion from filter paper discs is used. The advantages of the method in terms of low cost and reliability for determining the actual antimicrobial activity in the preparation are discussed. The assay method is in routine use in the production control of vaccines at our Institute.

Agar↗
PubMed1978

Prognosis of survival in a geriatric population.

With the aim of demonstrating prognostics as regards death in a geriatric population, the mortality among 1 486 patients (516 men and 970 women) in De Gamles By, Copenhagen, was observed over a 2-year period. The mortality curves for the groups examined were found to be rectilinear in logarithmic form and could therefore be described with sufficient certainty by one value, viz. the probability of death in any one year. The probability of death was just over 20% and was the same for both sexes. Of the parameters examined, particularly high mortality was found where there was urinary incontinence, severe mental abnormality, a great need for nursing, and poor physical mobility (especially inability to walk). On the other hand, there was no particular relationship with age. Where the degree of the handicapping factors was severe, there was generally greater mortality among the men than among the women, but this was not so in the less severe cases. The length of stay in the institution had no effect on the mortality. The results of the present study are in good agreement with previous findings reported from New York (7).

Aged↗
PubMed1978

Minimum need for care in geriatric institutions.

On the basis of a study from De Gamles By, Copenhagen, concerning the mortality and changes in the patients' need for nursing care over a 2-year period, calculation is made of the time-related changes in the care status, using a special model for homes for elderly persons. This model is based on a policy that only independent persons are received into such homes and that they remain there until they die. It is found that the need for care becomes stabilized after a period of 5-6 years and remains at a level corresponding to about 45% independent, 36% slightly dependent, and 17% heavily dependent patients (the "minimum need for care"). Using the model, a few examples are given to illustrate the changes which would arise in the need for care in De Gamles By if, on the basis of the primary care status on January 15, 1969, (A) only independent patients were admitted, and (B) the current admittance policy was continued.

Aged↗
PubMed1978

Some aspects concerning admittance to and accommodation in geriatric institutions housing persons with varying degrees of need for care.

On the basis of an account of the mortality and changes in the need for care over a 2-year period among independent persons and patients requiring care in De Gamles By, Copenhagen, an assessment is made of the movements of patients and the need for care in a model of a geriatric institution. This model includes both purpose-built residential apartments for independent persons and places for dependent patients requiring nursing care. It is shown that the accommodation for the latter patients rapidly becomes occupied by the independent persons from the residential apartments who subsequently need nursing care. Thus, the places in the nursing section are blocked for the admittance of dependent persons living in the community outside. This situation arises when there are equal numbers of both types of accomodation. Where the number of residential apartments is greater than the number of places in the nursing section the care function must be transferred to the residential apartments, and this is regarded as impracticable.

Aged↗
PubMed1978

Minimum variability in the need for care in geriatric institutions.

Based on an account of the need for nursing care in the entire patient population in De Gamles By, Copenhagen, on January 15, 1967, and again on January 15, 1969, it is shown that the need for care varies considerably, despite a policy of admitting only independent persons. The consequences of this variability for the size of the nursing staff required are discussed, together with some aspects of admittance policy.

Aged↗
PubMed1977

Antibiotic policy and spread of Staphylococcus aureus strains in Danish hospitals, 1969-1974.

In the period 1969-1974 a decreasing number of Danish hospital departments recorded epidemic occurrences of Staphylococcus aureus strains, and the local spread of strains was less extensive. Multiple-resistant strains of the 83 A complex were succeeded by type 94 strains, resistant to penicillin only. The level of methicillin resistance fell from 19 to 6%. 12% of methicillin resistant strains are now sensitive to streptomycin and/or tetracyclines; they do not represent a few clones, but belong to a wide spectrum of phage types. The changes follow a reduction in the consumption of streptomycin and tetracyclines not of methicillin or other penicillins. As a contrast to the general reduction of combined resistance to streptomycin and tetracyclines, the strains in dermatological departments, where tetracyclines are commonly used, maintain a high degree of resistance to tetracyclines alone.

Air Microbiology↗
PubMed1976

The incidence of Mycoplasma pneumoniae infections in Denmark over the past seventeen years: a review.

The variations in the incidence of Mycoplasma pneumoniae infections in Denmark over a period of 17 years could be demonstrated in the central serological laboratory which serves the whole of the population. This observation was made possible for the first and major part of this study by testing cold agglutinin (CA) positive sera, which had been kept frozen sine 1958, for antibodies to M.pneumoniae. The second part of the study is based upon results from routine tests for CA and M.pneumoniae antibodies on all samples which we receive. A statistical analysis of the total material indicates that four epidemics of M.pneumoniae antibodies on all samples which we receive. A statistical analysis of the total material indicates that four epidemics of M.pneumoniae infection had taken place from January 1958 to December 1974 and that these epidemics occurred at regular four and a half year intervals. By a follow-up of the study a fifth epidemic was demonstrated during the first eight months of 1975 which broke the regular periodicity by appearing two years earlier than expected. The consequences of including only CA positive sera in this study was investigated. Antibodies to M.pneumoniae were measured by either an indirect immunofluorescence test, an indirect haemagglutination test or a complement fixation test. The observed difference in sensitivity of these tests is discussed in relationship to a possible influence on the overall incidence.

Agglutinins↗
PubMed1976

Epidemics of Mycoplasma pneumoniae infection in Denmark from 1958 to 1974.

The study is a retrospective and prospective serological investigation of the incidence of Mycoplasma (M.) pneumoniae infection in Denmark during a 17-year period. By least square multiple regression analysis it was shown that four major outbreaks or epidemics had occurred which culminated at regular intervals of four and a half years. The study was based on cold agglutinin (CA) positive sera tested for antibodies to M. pneumoniae by an indirect immunofluorescence (IF) test, an indirect haemagglutination (IHA) test or a complement fixation (CF) test. By the criteria chosen for a positive test, the CF test was found to detect more cases than the IF or IHA tests. A shift during the study from the latter two tests to the CF test influenced the incidence, but not the periodicity of epidemics. The consequence of including only CA positive sera in the study was investigated.

Adolescent↗
PubMed1976

Decreased delayed hypersensitivity to tuberculin demonstrated in experimental leptospirosis in guinea pigs.

Skin reactivity to tuberculin has been studied during the course of experimental leptospirosis in guinea pigs. A depression of the delayed hypersensitivity to tuberculin was demonstrated in the infected animals. The depression was most pronounced when icterus had developed. The depression was not correlated with the amount of infectious units administered or with the demonstration of live leptospirae in the peritoneal cavity. In the infected animals there was no correlation between the initial and the final skin tests which is in contrast to findings in the control group.

Animals↗
PubMed1976

Staphylococcus aureus strains isolated in Danish hospitals from January 1st, 1966, to December 31st, 1974.

During the years 1966-1974, 167,297 strains isolated from 167,297 patients or staff members in Danish hospitals were registered at Staten Seruminstitu. All the strains were phage-typed and examined for production of a 'Tween'-80-splitting enzyme and resistance to mercuric chloride. 158,236 strains were examined for resistance to antibiotics. Since 1968, a steep decrease in the number of strains resistant to three or more antibiotics (multiple-resistant) and in strains of the 83A complex was noticed. In recent years an increase in strains belonging to phage-group I and in those referred to as miscellaneous and non-identified was registered. The increase in the non-typable strains might be explained by the shift of the concentration of the typing phages from 1000 X RTD to 100 X RTD. It is concluded that at least two factors may have contributed to the reduction of the multiple-resistant strains: an altered antibiotic policy, restricting the use of streptomycin and tetracyclines, and an improved hospital hygiene, diminishing the spread of identical strains within the various departments. However, it is emphasized that the consumption of methicillin is still increasing.

Bacteriophage Typing↗