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Biomedical subjects

T Johansson

Publications and source records attributed to T Johansson.

At least 19 recordsLinked to original sources
PubMed1992

Growth of Salmonella and competing flora in five commercial Rappaport-Vassiliadis (RV)-media.

Growth of 18 Salmonella strains belonging to 11 serotypes and the bacterial flora of deep-frozen broiler carcasses was examined in five commercial Rappaport-Vassiliadis (RV) media. Growth was measured by an automated turbidometer (Bioscreen). Significant differences in performance between the media investigated were observed. The unequal performances were ascribed to differences in the concentration of magnesium chloride (MgCl2) and the type of peptone used.

Animals↗
PubMed1992

The 17 kDa lipoprotein and encoding gene of Francisella tularensis LVS are conserved in strains of Francisella tularensis.

A T-cell-stimulating 17 kDa protein of the vaccine strain Francisella tularensis LVS has previously been cloned, sequenced and shown to be a lipoprotein. In the present study, it was investigated whether the protein, denoted TUL4, and its gene are present in various strains of the genus Francisella. By Western blot analysis, it was demonstrated that a TUL4-specific monoclonal antibody bound to a protein present in each of the Francisella strains. The immunoreactive proteins had an M(r) of 17 kDa in all F. tularensis strains and in the strain Francisella novicida, whereas the M(r) in strains of Francisella philomiragia was 20 kDa. When genomic preparations were probed with a radioactive DNA fragment of F. tularensis LVS encoding TUL4, hybridization was demonstrated in all strains of Francisella, although the F. philomiragia strains did not hybridize under conditions of high stringency. The hybridizing chromosomal DNA fragment of the F. philomiragia strains was larger than that of the other Francisella strains. No hybridization or Western blot reactivity was seen when various other Gram-negative and Gram-positive bacteria were probed. In summary, the 17 kDa lipoprotein of F. tularensis LVS appears to be Francisella-specific and present in the species F. tularensis and F. novicida, whereas an immunologically related protein is present in F. philomiragia.

Bacterial Proteins↗
PubMed1992

A three-dimensional architecture for a parallel processing photosensing array.

A three-dimensional architecture for a photosensing array has been developed. This silicon based architecture consists of a 10 x 10 array of photosensors with 80 microns diameter, through chip interconnects to the back side of a 500 microns thick silicon wafer. Each photosensor consists of a 300 x 300 microns pn-junction photodiode. The following processes were used to create this photosensing architecture: 1) thermomigration of aluminum pads through an n-type silicon wafer; 2) creation of pn-junction photosensors on one side of the wafer; and 3) creation of aluminum pad ohmic contacts to the thermomigrated, through chip interconnects and the substrate on the back side of the wafer. The electrical and optical characteristics of the three-dimensional architecture indicates that it should be well suited as a photosensing framework around which a "silicon retina" could be built.

Artificial Organs↗
PubMed1992

Immunogenicity and toxicity of lipopolysaccharide from Francisella tularensis LVS.

Lipopolysaccharide (LPS) from the live vaccine strain of Francisella tularensis (F. tularensis LVS) was isolated and purified. The LPS did not stimulate lymphocytes from previously tularaemia-vaccinated individuals or lymphocytes from non-primed individuals. However, serum antibodies from tularaemia vaccinees reacted with the LPS whereas virtually no reactivity was found with antibodies from individuals not exposed to F. tularensis LVS. Antibodies of immunoglobulin class M displayed the antibody reactivity predominantly. The LPS failed to induce the mononuclear cell-derived cytokine interleukin-1 and only low levels of tumour necrosis factor were detected. Furthermore, no LPS endotoxin properties were found in galactosamine-treated mice or in the Limulus amoebocyte lysate assay. From these results it can be concluded that F. tularensis LVS possesses a lipopolysaccharide-like molecule, which does not exhibit properties of a classical endotoxin.

Animals↗
PubMed1991

The use of ink jets in ultrasound registrations.

The continuous ink jet method developed by Professor Hellmuth Hertz, Lund Institute of Technology, Sweden, is today used in printers that print digitally stored high-quality images rapidly and at low cost. The development started in the late 1950s when there was a need for a direct registration method for ultrasound echocardiograms. The development steps are described from the early ultrasound registrations to the true halftone printing of digital images today. Images from ultrasonic color Doppler examinations have been printed by an ink jet printer at our laboratory. The color capabilities of the printer are further illustrated by the printing of pseudo-colored gray-scale images and an image where color is used to highlight differences between two gray-scale images. The results show that the printer based on continuous ink jets is an interesting alternative to the existing hard-copy devices for medical images.

Echocardiography, Doppler↗
PubMed1991

Surface polymers of the nematode-trapping fungus Arthrobotrys oligospora.

The nematophagous fungus Arthrobotrys oligospora captures nematodes using adhesive polymers present on special hyphae (traps) which form a three-dimensional network. To understand further the adhesion mechanisms, A. oligospora surface polymers were visualized by transmission electron microscopy and characterized by chemical methods. Both traps and hyphae were surrounded by a fibrillar layer of extracellular polymers which stained with ruthenium red. The polymer layer was resistant to most of the chemicals and enzymes tested. However, part of the layer was removed by sonication in a Tris-buffer or by extraction in a chaotropic salt solution (LiCl), and the structure of the polymers was modified by treatment with Pronase E. Chemical analysis showed that the crude extracts of surface polymers removed by sonication or LiCl solution contained neutral sugars, uronic acids and proteins. Gel chromatography of the extracts revealed that the major carbohydrate-containing polymer(s) had a molecular mass of at least 100 kDa, containing neutral sugars (75% by weight, including glucose, mannose and galactose), uronic acids (6%) and proteins (19%). There was more polymer in mycelium containing trap-bearing cells than in vegetative hyphae. SDS-PAGE of the extracted polymers showed that the trap-forming cells contained at least one protein, with a molecular mass of approx. 32 kDa, not present on vegetative hyphae. Examining the capture of nematodes by traps of A. oligospora in which the layer of surface polymers was modified, or removed by chemical or enzymic treatments, showed that both proteins and carbohydrate surface polymers were involved in the adhesion process.

Animals↗
PubMed1990

Splenectomy for haematological diseases.

Two hundred patients with various haematological diseases underwent splenectomy between 1974 and 1986. The diagnoses were: Hodgkin's disease (n = 76), hairy cell leukaemia (n = 25), idiopathic thrombocytopenic purpura (n = 20), chronic lymphatic leukaemia (n = 19), haemolytic anaemia (n = 18), non-Hodgkin lymphoma (n = 16), myelofibrosis (n = 10), chronic myeloid leukaemia (n = 6), spherocytosis (n = 4), and miscellaneous (n = 6). Many of the patients were treated with corticosteroids and in poor general condition, partly as a result of chemotherapy. There were 37 postoperative complications in 29 patients (14.5%); two died, both of septicaemia. Pneumonia, bleeding, and wound infection were the most common complications, occurring in 9, 8, and 6 patients, respectively. Twelve patients required reoperation, eight for bleeding, two for intra-abdominal abscesses, and one each for pancreatitis and bowel perforation. There was no association between the diagnosis and the type of postoperative complication, but patients whose spleens weighed more than 2 kg had an increased incidence of postoperative complications (30%). We conclude that elective splenectomy is a safe treatment for haematological diseases, even in high risk patients.

Adolescent↗
PubMed1989

S-100 protein in cerebrospinal fluid after aneurysmal subarachnoid haemorrhage: relation to functional outcome, late CT and SPECT changes, and signs of higher cortical dysfunction.

The concentration of S-100 protein measured in ventricular cerebrospinal fluid (CSF) from 32 patients with subarachnoid haemorrhage (SAH) during the acute phase was related to features on admission such as the Hunt and Hess neurological scale and the amount of blood at the first computed tomography (CT). The S-100 values were also related to functional outcome assessed by the Glasgow outcome scale (GOS) at 12 months. Twenty-two patients were re-examined more than 2 years after the SAH, and the initial S-100 values were related to signs of structural brain damage at CT and single photon emission computed tomography (SPECT) and to the results of neuropsychological evaluation (NPE). NPE included standardized tests for memory functions, intellectual functions, visuo-spatial abilities, sensory-motor functions, and concept formation. Life-adjustment was assessed by two separate questionnaires. Tests for agnostic dysfunction and the Western aphasia battery test (WABT) were also performed. Patients who were functionally disabled or ultimately died had significantly higher initial CSF concentrations of S-100 protein than patients showing good recovery. Patients with low-attenuated regions and/or increased ventricular size at CT and/or regionally decreased tracer uptake on SPECT had higher S-100 levels during days 2-8 than had patients showing no such changes. Logistic and multiple regression analysis of all characteristics assessed during the acute phase after SAH showed that the CSF S-100 concentration during days 2-8 was the factor best correlated to GOS and findings on CT and/or SPECT. All patients showed varying degrees of cognitive impairment at follow-up. The results of NPE and the WABT were related to outcome assessed by GOS and to increased ventricular size on CT. Women had a stronger feeling of maladjustment, but the scores for life adjustment were otherwise not related to other outcome criteria. It is concluded that the ventricular CSF S-100 concentration during the acute phase after SAH is related not only to the functional outcome as assessed by GOS but also to signs of brain damage seen on late CT and SPECT.

Adult↗
PubMed1989

Cloning and characterization of variable-sized gypsy mobile elements in Drosophila melanogaster.

A cosmid genomic library from a known gypsy-induced forked mutation, f1, was screened by 32P-labeled gypsy transposable element. Of more than 250 positive clones we randomly selected 21 for in situ hybridization to wild-type polytene chromosomes. Two clones hybridized to region 15F on the X-chromosome, the cytological position of forked. A third clone hybridized to at least 17 sites on the chromosomes indicating the presence of repetitive sequences in the gypsy flanking DNA. All clones labeled the centromeric regions heavily. Ten clones, including the two hybridizing at 15F, were chosen for further analysis, and restriction mapping allowed us to place them into three groups: (1) full-length, (2) slightly diverging, and (3) highly diverging gypsy elements. Group (2) is missing the XbaI site in both their long terminal repeats (LTRs) as well as the middle HindIII site; four of these gypsy elements also have a approximately 100-bp deletion at the 5' LTR. The group (3) gypsy transposons are missing one LTR and also have highly diverging DNA sequences. The restriction analyses further imply that most of these different gypsy elements are present in more than one copy in the genome of the f1 stock used in this study. The results raise intriguing questions regarding the significance of transposable elements in evolution and biological functions.

Animals↗
PubMed1989

Presence of mutans streptococci and various types of lactobacilli in interdental spaces related to development of proximal carious lesions.

During a 2-yr study period samples from saliva, the tongue, and 276 interdental spaces were obtained from 23 7-yr-old children in order to (a) relate the presence of lactobacilli in various oral sites to the occurrence of lactobacilli in saliva, and (b) relate the presence of mutans streptococci and various types of lactobacilli interdentally to the development of proximal carious lesions. The results showed an increased number of interdental samples containing lactobacilli with an increasing number of salivary lactobacilli. Furthermore, lactobacilli were never found interdentally without the presence of mutans streptocci, lactobacilli proved to be the more suitable microorganism for prediction of proximal carious lesions. Neither the number nor the differentiation into different species of interdental lactobacilli seemed to be of importance, but simply whether they were present. The presence of lactobacilli probably reflects a caries-inducing environment (etiologic microflora + fermentable carbohydrates), thus explaining their high predictive ability compared to their rather limited etiologic importance in the initiation of decay.

Child↗
PubMed1988

Cerebral infarctions studied by [123I]iodoamphetamine. Clinical aspects of the findings on single photon emission computed tomography and transmission computed tomography.

We have used single photon emission computed tomography (SPECT) and the radioisotope [123I]-iodoamphetamine to study 16 patients with cortical and central cerebral infarctions. In 12 cases SPECT, in addition to changes at the site of infarction, showed areas of deficient uptake in other regions of the brain. Diaschisis as well as infarctions, not detected on the transmission computed tomography scanning, seem to explain these findings.

Aged↗