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Biomedical subjects

H Kristensen

Publications and source records attributed to H Kristensen.

At least 19 recordsLinked to original sources
PubMed2000

Selective mutism and comorbidity with developmental disorder/delay, anxiety disorder, and elimination disorder.

OBJECTIVES: To assess the comorbidity of developmental disorder/delay in children with selective mutism (SM) and to assess other comorbid symptoms such as anxiety, enuresis, and encopresis. METHOD: Subjects with SM and their matched controls were evaluated by a comprehensive assessment of the child and by means of a parental structured diagnostic interview with focus on developmental history. Diagnoses were made according to DSM-IV. RESULTS: A total of 54 children with SM and 108 control children were evaluated. Of the children with SM, 68.5% met the criteria for a diagnosis reflecting developmental disorder/delay compared with 13.0% in the control group. The criteria for any anxiety diagnosis were met by 74.1% in the SM group and for an elimination disorder by 31.5% versus 7.4% and 9.3%, respectively, in the control group. In the SM group, 46.3% of the children met the criteria for both an anxiety diagnosis and a diagnosis reflecting developmental disorder/delay versus 0.9% in the controls. CONCLUSIONS: SM is associated with developmental disorder/delay nearly as frequently as with anxiety disorders. The mutism may conceal developmental problems in children with SM. Children with SM often meet diagnostic criteria for both a developmental and an anxiety disorder.

Adolescent↗
PubMed1998

Pyomyositis due to non-haemolytic streptococci.

We present a unique case of a multifocal non-tropical pyomyositis due to non-haemolytic streptococci in a 36-y-old woman. The initial infection was in an area of contused muscle in the left anterior thigh and spread to the contralateral femoral and gluteal musculature. There was a previous history of Staphylococcus aureus pyomyositis and colitis ulcerosa. The patient was treated successfully with surgical drainage and parenteral antibiotics.

Adult↗
PubMed1997

Elective mutism--associated with developmental disorder/delay. Two case studies.

Elective mutism (EM) is not regarded as a separate diagnostic category in the ICD-9, but is included under the heading "313: Disturbance of emotions specific to childhood and adolescence." In the ICD-10 EM is acknowledged as a separate diagnosis defined as "a marked, emotionally determined lack of speech in certain situations in a child with a normal or near normal speech/language ability." The diagnosis excludes pervasive developmental disorder and specific developmental disorders of speech and language. Two patients referred for EM to a child and adolescent psychiatry outpatient clinic, showed specific developmental delays and assessment indicated slight mental retardation in one of them. The question arose regarding how extensively EM is reported in the literature as associated with developmental disorder/delay. A search was carried out in four data-bases where most references were listed under the keyword "mutism". This paper presents the two case studies, and the results of the literature inventory. It concludes that EM may be associated with developmental disorder/delay and suggests that this could be a predisposing factor for an emotionally determined lack of speech in certain situations.

Causality↗
PubMed1995

Amphetamine redistributes dopamine from synaptic vesicles to the cytosol and promotes reverse transport.

Whether amphetamine acts principally at the plasma membrane or at synaptic vesicles is controversial. We find that d-amphetamine injection into the Planorbis giant dopamine neuron causes robust dopamine release, demonstrating that specific amphetamine uptake is not required. Arguing for action at vesicles, whole-cell capillary electrophoresis of single Planorbis dopamine neurons shows that amphetamine reduces vesicular dopamine, while amphetamine reduces quantal dopamine release from PC12 cells by > 50% per vesicle. Intracellular injection of dopamine into the Planorbis dopamine neuron produces rapid nomifensine-sensitive release, showing that an increased substrate concentration gradient is sufficient to induce release. These experiments indicate that amphetamine acts at the vesicular level where it redistributes dopamine to the cytosol, promoting reverse transport, and dopamine release.

Amphetamine↗
PubMed1993

Is tissue factor pathway inhibitor involved in the antithrombotic effect of heparins? Biochemical considerations.

Tissue factor pathway inhibitor (TFPI) is released into the circulation after intravenous or subcutaneous injection of heparin or low-molecular-weight heparin (Logiparin) in humans. The plasma concentration of TFPI is increased 2- to 4-fold by a prophylactic dose of Logiparin, and this excess TFPI remains in the circulation only in the presence of the heparin. TFPI and heparin show strong synergism in clotting assays at concentrations obtained after heparin injection in humans. Animal studies have demonstrated that TFPI by itself has antithrombotic properties. It is concluded that the release of TFPI may contribute significantly to the antithrombotic effect of heparin.

Animals↗
PubMed1991

Radiation resistance of clinical Acinetobacter spp.: a need for concern?

As part of an epidemiological investigation of hospital infections caused by Acinetobacter spp. the radiation resistance of 15 clinical isolates and four reference strains was assessed. The radiation resistance (in D-6 values, viz. the dose necessary for reducing the initial number of colony forming units by a factor of 10(6)) was, in general, higher in the isolates of A. radioresistens than in the isolates of the A. calcoaceticus-A. baumannii complex and of A. lwoffi. However, the least resistant isolates of A. radioresistens had a D-6 value equal to or lower than the most resistant isolates of the other groups. The lowest D-6 values found were for two of the reference strains. The highest D-6 value was 35 kGy. Three isolates of A. johnsonii could not survive long enough in a dried preparation to make an assessment of the D-6 values possible. The radiation resistance of the 15 clinical isolates in the present study was higher than the resistance found in a study of similar isolates in 1970.

Acinetobacter↗
PubMed1991

Simultaneous presence of tissue factor pathway inhibitor (TFPI) and low molecular weight heparin has a synergistic effect in different coagulation assays.

Injection of heparin releases tissue factor pathway inhibitor (TFPI) to the blood and, after heparin neutralization, it has been recently demonstrated that the released TFPI has an anticoagulant activity. Using recombinant TFPI (rTFPI) we have investigated how the simultaneous presence of TFPI and low molecular weight heparin (LMW heparin) affects different coagulation assays. Coagulation was measured using the activated partial thromboplastin time, the prothrombin time and a dilute tissue factor assay. The anticoagulant activity of partly purified plasma TFPI (pTFPI) was much higher than that of TFPI. However, this high anticoagulant activity was unstable, so in order to investigate the effect of pTFPI and LMW heparin we used an inhibitory antibody towards TFPI and looked at the effect of removing TFPI from plasma. When both rTFPI and LMW heparin was added to plasma a synergistic effect was observed in all assays. In the tissue factor dependent coagulation assays, the effect of adding rTFPI or removing pTFPI was more pronounced in the presence of heparin. TFPI plays a significant role in assays where the coagulation time is prolonged for some reason. This may be caused by dilution of tissue factor, by the presence of heparin or by a defect in the coagulation cascade such as that seen in haemophilia.

Blood Coagulation Tests↗
PubMed1991

Radiation resistance of microorganisms on unsterilized infusion sets.

Three different methods were used for detecting and isolating microorganisms with high radiation resistance from the microbial contamination on infusion sets prior to sterilization. By all three methods, microorganisms with a radiation resistance high enough to be a critical factor in a sterilization process (D-6 value greater than or equal to 30 kGy) were found with a frequency of approximately two colony forming units (cfu) per 100 product items, even though the product items in two of the series of analyses were irradiated with doses of 3-6 kGy. The frequency of occurrence of isolates with D-6 values greater than or equal to 30 kGy was 0.45 per 1000 cfu of the total aerobic count. Eight different isolates of microorganisms had D-6 values greater than or equal to 40 kGy when irradiated in dried laboratory preparation. All but one of these were classified according to morphologic criteria as Deinococcus, and all but one had nonlinear dose-response relationships in semilogarithmic presentation.

Bacteria↗
PubMed1982

Radiation resistance of Candida parapsilosis.

The radiation resistance of 30 strains classified as Candida parapsilosis was examined. The strains originated partly from environments where ionizing radiation was used for research or routine purposes, partly from environments with no known possibility for selection of strains with unusually high radiation resistance. D-6 values between 1.5 and 2.4 Megarads were found when the cells were irradiated in the dried state, a D-6 value being the dose necessary to reduce the initial number of colony-forming units with a factor of 10(6). The majority of D-6 values were between 1.9 adn 2.1 Megarads. D-6 values for the cells irradiated in liquid media were about 2/3 of those in the dried state. No difference in resistance was revealed depending on the origin of the strains examined For radiation sterilization of medical products the demonstrated resistance of Candida parapsilosis might be of importance if routine use of minimum doses below 2.5 Megarads were to be accepted.

Candida↗
PubMed1982

In-use tests of disinfectants.

In two different laboratories three methods were applied for in-use testing of 400 samples of disinfectants, primarily aldehyde and phenolic solutions, collected in 30 wards at 11 Danish hospitals. The results obtained with the Kelsey-Maurer test, the membrane filtration technique, and a standardized challenge test were in complete accordance, however, the challenge test revealed a few more inefficient samples, than the two other methods. For routine use at hospital laboratories the choice between the Kelsey-Maurer test or the modified Kelsey-Maurer technique using membrane filtration may be guided by the available equipment. The design and the application of a challenge test and pertinent criteria for test strains are discussed. Only about 3% of the samples failed to pass the tests, but a predominance (10%) of failures among the samples, received as number one in a series, underlines the didactic aspects of in-use testing. The study demonstrates that suitable methods exist and may be of value when introduced in the local policy of controlling disinfectants.

Bacillus↗
PubMed1981

Radiation-resistant micro-organisms isolated from textiles.

Towels from private homes and public offices and underwear contaminated by being used by employees at a public health laboratory were examined for occurrence of radiation-resistant bacteria and fungi. Three different methods were used for isolation of the most resistant organisms, one with multiplication of the microbial population prior to an irradiation used for selection, and two without this multiplication and with the organisms placed on membrane filters or in situ on the textiles, respectively. A total of 44 different strains were isolated. Differences in the three methods used for selection of the most radiation-resistant microorganisms were not reflected in the results. 16 pigment-producing Gram-positive cocci, tentatively classified as Micrococcus radiodurans, were the most radiation-resistant and were isolated in about half of the examinations. Other Gram-positive cocci, non-spore forming rods, some Nocardia and Candida parapsilosis strains and two Bacillus strains constituted the rest of the collection. Wtih few exceptions dose-response curves for the strains were upward convex. D-6 values were determined to be between 1.5 megarad for the most radiation sensitive, a Candida, and 5.7 megarad for the most resistant,, tentatively classified as M. radiodurans. The D-6 values for the Bacillus strains were in both cases 1.8 megarad, consistent with a D-value of 0.3 megarad. The same resistance is reported to be the maximum resistance for B pumilus, strain E601, commonly used as reference strain in the literature on radiation sterilization of medical devices and supplies.

Bacteria↗
PubMed1979

Biological indicators for the control of ethylene oxide sterilization.

A new biological indicator has been developed for the control of ethylene oxide sterilization, particularly for large scale sterilization of disposable medical equipment. The aim has been to provide the new indicator with the same resistance to the combined effect of ethylene oxide and water vapour as the biological indicator referred to by the health authorities in Scandinavia. The reference indicator contains spores of a Danish test strain, Bacillus subtilis, in sand. The new one contains spores of a test strain used extensively for biological indicators, viz. B. subtilis var. niger (B. globigii). The spores in the new preparation are dried in pieces of cotton yarn. The two indicators were exposed to ethylene oxide and water vapour in five different series of experiments and almost the same resistance was found. In simulated routine sterilization procedures, the new indicator was placed at locations not easily accessible for the gas and water vapour, and the results reflected the blockage of diffusion. The experiments included samples of household dust. The resistance of the microorganisms in the dust was compared with that of the biological indicators. Based on these comparisons, it is concluded that the resistance of the two biological indicators to ethylene oxide is in accordance with the official Scandinavian standard for sterilized medical equipment when used in the control of sterilization of products with low microbial contamination.

Bacillus subtilis↗
PubMed1975

Structural X-chromosome abnormality in a female with gonadal dysgenesis.

A patient with gonadal dysgenesis and 46 chromosomes is described. In the inactive X chromosome there seems to be a deletion of the short arms and an insertion of heterochromatin in the long arms. The most probable mechanism to explain this structurally abnormal X is a pericentric inversion, with breakage and union having occurred in the centromeric heterochromatin of the short arm and in band q23 of the long arm. An amplification of the centromeric heterochromatin left in the short arm is also supposed.

Adult↗