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Biomedical subjects

C Johansson

Publications and source records attributed to C Johansson.

At least 145 records · Page 8Linked to original sources
PubMed1994

Magnetic characterization of iron oxides for magnetic resonance imaging.

The OMP particle and four additional iron oxide samples were investigated in terms of zero field cooled magnetization (ZFCM) curves and hysteresis loops. The observation of superparamagnetic blocking and the absence of magnetic remanence demonstrated that the samples are superparamagnetic at room temperature. The magnitude of the ZFCM peak temperatures are in qualitative agreement with the iron oxide crystal size. One sample deviated from the remaining four in that it had a significantly lower magnetic moment and an irregular ZFCM curve showing the presence of various less magnetic phases. The similar results obtained with the OMP particles and the individual OMP crystallites without the polymer support show that the superparamagnetic properties of the individual OMP crystallites are retained on the OMP particle. Depending on the application, the ZFCM experiment may be viewed as an alternative or a supplement to Mössbauer spectroscopy in studies of the superparamagnetic blocking of iron oxides.

Contrast Media↗
PubMed1994

Enterocele demonstrated by defaecography is associated with other pelvic floor disorders.

Sixty-nine patients with enterocele on defaecography, and 128 patients without enterocele but with other abnormal findings were investigated to identify concomitant colorectal disorders and their relationship with enterocele. Of the 69 patients with enterocele, 38 (55%) had concomitant rectal intususception and 26 (38%) rectal prolapse. Abnormal physiological findings on anorectal manometry and electrophysiology were more common in patients with enterocele. Previous hysterectomy increased the risk of enterocele formation. The study has demonstrated that patients with enterocele should be investigated thoroughly for other lesions before treatment is planned. Further investigation of the role of enterocele in patients with defaecation disorders is required.

Adolescent↗
PubMed1994

A high weight gain early in life is associated with an increased risk of type 1 (insulin-dependent) diabetes mellitus.

Growth during the first years of life in relation to type of feeding in infancy was retrospectively studied in an unselected population-based group of 297 children who had been diagnosed with Type 1 (insulin-dependent) diabetes mellitus before the age of 15 years (probands) and 792 individually-matched referent subjects. Reliable data were collected from child welfare clinics. Probands weighed slightly less at birth but their weight gain at 6, 9, 18 and 30 months of age was significantly greater (p < 0.02) than that of referent children. The weight gain of children who had never been breast-fed was more marked than that of breast-fed children; this was found for both probands and referent children. But also among exclusively breast-fed children (> 2 months), probands gained significantly more in weight from birth up to 18 and 30 months of age than exclusively breast-fed referent children. Early weight gain appears to be a risk factor for development of Type 1 diabetes. The lower weight gain in breast-fed compared to non-breast-fed children may explain the protective effect of breast feeding against Type 1 diabetes observed in several studies.

Adolescent↗
PubMed1994

Defecography. Results of investigations in 2,816 patients.

PURPOSE: This study was designed to analyze the frequency of different findings at defecography in patients with defecation disorders and see in what way the evaluation could be improved. METHODS: The reports of investigations in 2,816 patients were analyzed. RESULTS: Twenty-three percent of the investigations were considered normal. Thirty-one percent of the patients had rectal intussusception, 13 percent had rectal prolapse, 27 percent had rectocele, and 19 percent had enterocele. Twenty-one percent of the patients had a combination of two or three of these diagnoses. The combination of rectocele and enterocele was rare. The majority of patients with enterocele had other concomitant findings. Patients with or without abnormal perineal descent had similar frequencies of rectal prolapse, rectal intussusception, and enterocele. Rectocele was more common in patients with abnormal perineal descent. CONCLUSIONS: Defecography is valuable when investigating patients with defecation disorders. Pathologic findings were found in 77 percent of the patients. A standardized protocol should ensure a complete evaluation of defecography.

Adolescent↗
PubMed1994

Enterocele is correctable using the Ripstein rectopexy.

PURPOSE: About one-third of the patients with rectal prolapse or rectal intussusception have concurrent enterocele at defecography. The purpose of this study was to evaluate the effect of the Ripstein procedure on the concurrent enterocele and to study the outcome of the procedure with respect to the patients' symptoms. METHODS: Twenty-two patients with enterocele and either rectal prolapse or rectal intussusception at defecography were treated using the Ripstein procedure. Postoperatively, the patients were evaluated with clinical examination (22 patients) and defecography (16 patients). RESULTS: None of the patients had recurrence of enterocele, rectal prolapse, or intussusception at postoperative follow-up. Continence was improved in 15 of 16 incontinent patients. Emptying difficulties were unchanged in eight patients, improved in five patients, and had deteriorated in four patients. CONCLUSIONS: Enterocele is corrected by using the Ripstein rectopexy. Persisting defecation difficulties after the Ripstein procedure are unlikely to be secondary to enterocele. The Ripstein procedure can be an alternative in the treatment of enterocele, as a majority of these patients also have rectal prolapse or rectal intussusception.

Defecation↗
PubMed1994

HCl-stimulated duodenal HCO3- secretion in conscious rat. Interactions among VIP, nicotinic receptor mechanisms, and prostaglandins.

Using an isolated loop of the proximal duodenum of conscious rats, the role of vasoactive intestinal peptide (VIP) in the duodenal HCO3- response to HCl was examined, especially interactions with participating cholinoceptor mechanisms and prostaglandins. A 5-min perfusion with 150 mmol/liter HCl increased luminal VIP during 3 hr, with a peak output during and immediately after the acid challenge. The HCl-stimulated output was unaffected by atropine and hexamethonium, but was augmented by indomethacin from 13.6 (9.5-17.8) to 39 (20-85) fmol/cm/min. The HCO3- secretion in response to graded doses of intravenous VIP (0.00625-6 nmol/kg/30 min) was dose-dependent to maximally 33.5 +/- 10.5 mumol/cm/hr. The HCO3- secretion during a single intravenous infusion of VIP (12 nmol/kg/hr), 13.9 +/- 4.2 mumol/cm/hr, was unchanged by atropine, reduced to 10.0 +/- 3.5 mumol/cm/hr by hexamethonium, and augmented to 18.9 +/- 4.7 mumol/cm/hr by indomethacin. Exogenous VIP did not change the basal luminal output of PGE2; neither did exogenous PGE2 nor indomethacin affect the basal luminal output of VIP. HCl-induced increases in luminal outputs of VIP, substance P, and neurokinin A (the two latter with unknown roles) were differentially affected by atropine, hexamethonium, and indomethacin, indicating that the acid challenge released the peptides through controlled mechanisms. In conclusion, in the duodenal HCO3- response to luminal HCl, VIP may have a stimulatory role, which partially depends on nicotinic, but not on muscarinic cholinoceptor mechanisms, and which is negatively modulated by prostaglandins.

Animals↗
PubMed1994

The atypical antipsychotic, remoxipride, blocks phencyclidine-induced disruption of prepulse inhibition in the rat.

The effect of various typical (haloperidol) and atypical (clozapine, raclopride, remoxipride) antipsychotics on phencyclidine (PCP)-induced disruption of sensorimotor gating was tested in rats using an acoustic startle paradigm. Clozapine (4-40 mumol/kg), haloperidol (1-5 mumol/kg) and raclopride (1-12 mumol/kg) failed to reverse PCP-induced disruption of prepulse inhibition (PPI) of the acoustic startle response. In contrast, remoxipride (12-60 mumol/kg) caused a dose-dependent block of this effect. PCP-induced disruption of PPI is a widely accepted animal model of a corresponding behavioural deficit observed in schizophrenia although little evidence has been presented that it is in fact sensitive to antipsychotic agents. The present results indicate that remoxipride behaves in a unique way in this model compared to clozapine, haloperidol and raclopride.

Acoustic Stimulation↗
PubMed1994

Development of tolerance to 8-OH-DPAT induced blockade of acquisition of a passive avoidance response.

We examined the effects of manipulating 5-HT1A receptors on the performance of a passive avoidance task in rats. Firstly, we studied the effect of racemic 8-OH-DPAT and compared it to the pure enantiomers (subcutaneous injection, s.c.). Secondly, we investigated the effect (s.c.) of the selective 5-HT1A receptor antagonist (S)-UH-301 [(S)-5-fluoro-8-hydroxy-2-(dipropylamino)tetralin] both alone and on 8-OH-DPAT-induced disruption of acquisition. Thirdly, we examined whether tolerance occurs to the effects of 8-OH-DPAT on passive avoidance acquisition. Finally, we examined the effects (s.c.) of the selective NMDA receptor antagonist dizocilpine, (+)-MK-801[(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohe pten-5, 10-imine], on this tolerance development. Different doses of racemic 8-OH-DPAT were injected 10 min before rats were exposed to the acquisition phase of a step through passive avoidance response. When tested for retention 24 h later, 8-OH-DPAT-pretreated rats failed to exhibit any avoidance. R(+) and S(-)-8-OH-DPAT were also active with the R(+)-isomer being more active than the S(-)-isomer. The 5-HT1A antagonist (S)-UH-301 [(S)-5-fluoro-8-hydroxy-2-(dipropylamino)tetralin] was without effect on avoidance performance but antagonized the effect of 8-OH-DPAT. In a further experiment, rats were pretreated with racemic 8-OH-DPAT (0.3 mg/kg). Twenty four hours later, they received a challenge dose of 8-OH-DPAT and exposed to the acquisition phase of the avoidance response. When tested 24 hr later for retention, 8-OH-DPAT challenged rats failed to show any indication of an avoidance response.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1994

Dopamine receptor antagonists block amphetamine and phencyclidine-induced motor stimulation in rats.

d-Amphetamine (DEX) and phencyclidine (PCP) increased motor activity in rats as measured in automated activity cages. Analysis of the stimulation indicated that both drugs increased horizontal activity (total activity), locomotion, and peripheral activity. However, DEX increased while PCP decreased the incidence of rearing. The ability of different drugs to antagonise DEX- and PCP-induced increases in total activity (called stimulation) was measured. Dopamine (DA) D1 receptor antagonists (SCH23390, NNC-01-0112) were 7-8 times more potent in blocking DEX than PCP. DA D2 receptor antagonists (raclopride, remoxipride, haloperidol) were only 1-2 times more potent against DEX-induced stimulation. Nonselective DA receptor antagonists were also tested. Chlorpromazine was more potent against DEX than against PCP. Buspirone and sertindole were slightly more potent in blocking PCP than DEX. Ritanserin (5-HT2 receptor antagonist) was inactive against both stimulants. 8-OH-DPAT (5-HT1A receptor agonist) potentiated the stimulant effects of DEX and PCP. Prazosin (alpha 1-adrenergic receptor antagonist) partially blocked both DEX and PCP. Most drugs tested depressed spontaneous motor activity. Remoxipride and sertindole, however, caused very little depression even at doses several times higher than those needed to block DEX or PCP. The data show clear pharmacological differences between DEX- and PCP-induced stimulation.

Animals↗
PubMed1994

Characterization of anti-GBM antibodies involved in Goodpasture's syndrome.

Goodpasture's syndrome is a life threatening autoimmune kidney disease. The patients have autoantibodies to the glomerular basement membrane, which are specific for the C-terminal domain of type IV collagen (NC1). The major antigen has been localized to the alpha 3 (IV)-chain. We have investigated sera from 44 patients with anti-NC1 antibodies. The quantity of antibodies to four different alpha(IV)-chains of type IV collagen was measured with direct ELISA. We used affinity chromatography to separate the antibodies and their specificities were studied with ELISA. The results show that about 1% of the patients total IgG are anti-NC1 antibodies and that 90% of these antibodies are specific for the alpha 3(IV)-chain. Antibodies to the other alpha(IV)-chains were found in 80% of the patients. Furthermore, affinity purified anti-alpha 3(IV) antibodies from one patient were inhibited by antibodies from the other patients, from 4 to 72%. The antibodies, from 39 of the patients, were inhibited by a monoclonal antibody against the alpha 3(IV)-chain. The results indicate that patients with Goodpasture's syndrome can have antibodies to most of the alpha(IV)-chains, while the majority of anti-NC1 antibodies are restricted to the alpha 3(IV)-chain. Moreover the number of epitopes seems to be limited and the majority of the antibodies from most patients are against one single epitope on the alpha 3(IV)-chain.

Anti-Glomerular Basement Membrane Disease↗
PubMed1994

A community-based population study of vertebral fractures in 85-year-old men and women.

Radiographic examinations for the presence of vertebral fracture between T4 and L5 were performed in a random sample of 85-year-old women (n = 304) and men (n = 158) who participated in a longitudinal study in Gothenburg. A vertebral fracture was defined as an anterior/posterior (A/P) vertebral height ratio of 0.66 or less. A severe vertebral fracture was defined as a compression of vertebral height of more than 33% both at the anterior and posterior edges compared to the posterior edge of the adjacent vertebral body. Bone mineral density was measured with dual photon absorptiometry in the right calcaneus. The most common site for vertebral fractures was L1 in women and Th12 in men. Bone mineral density in men at the age of 75 showed a significant correlation with vertebral fractures at 85 years of age (p < 0.001). This was not the case for women. Stepwise logistic analysis revealed that women with vertebral fractures at 85 years of age had more significant back pain, shorter stature, and more often a history of another fracture and/or chronic treatment with corticosteroids. In men, muscle strength, marital status and body weight at age 85 were the only factors significantly associated with vertebral fractures.

Aged↗
PubMed1994

Space-time clustering in insulin-dependent diabetes mellitus (IDDM) in south-east Sweden.

Using the method developed by Knox, space-time clustering was analysed in all 584 cases of insulin-dependent diabetes mellitus (IDDM) diagnosed between 1977-1990 and below the age of 16 from four paediatric departments in south-east Sweden. The catchment areas of these clinics form a contiguous geographical area of 26,445 km2 with a total of 165,784 children aged 0-15 years. The annual incidence for the study period was 25.2 per 100,000 children aged 0-15 years with a statistically significant incidence variation between the years; highest incidence in 1983 (39.2) and lowest in 1977 and 1989 (18.9 and 20.7 respectively). In the analysis, 30 different combinations of critical cutoff values were used to define closeness in space and time of pairs of cases. Statistically significant results were seen for several combinations with the highest significance obtained for the cutoff values of 15 km and 7 months, respectively. This space-time clustering tended to be specially pronounced during the period with the highest incidence of IDDM, 1981-1985. Our results indicate that space-time clustering exists in IDDM. These findings may support the hypothesis that infectious agents (possibly viral) give rise to a portion of IDDM.

Adolescent↗
PubMed1994

Risk factors for bone loss in chronic active hepatitis and primary biliary cirrhosis.

BACKGROUND: Data on risk factors for bone loss in chronic active hepatitis (CAH) and primary biliary cirrhosis (PBC) are scanty and/or conflicting. METHODS: Bone mineral density (BMD) in the distal forearm was measured using single-photon absorptiometry in 39 patients with CAH and 32 patients with PBC. We also attempted to identify risk factors for bone loss by means of a questionnaire and through a wide range of biochemical analyses. RESULTS: In the CAH patients BMD is inversely related to the duration of steroid treatment and to age at menarche. In the PBC patients there was a strong correlation between BMD and serum gastrin concentrations. CONCLUSIONS: Bone loss in CAH is to some extent explained by steroid treatment and delayed menarche. Bone loss in PBC may be reduced by increased calcitonin secretion induced by gastrocalcin.

Adrenal Cortex Hormones↗
PubMed1993

The solution structures of mutant calbindin D9k's, as determined by NMR, show that the calcium-binding site can adopt different folds.

The complete 1H NMR assignments have been obtained for five mutant proteins of calbindin D9k and the three-dimensional solution structures determined for two of the mutants. The structures have been determined using distance geometry and simulated annealing, with distance constraints from NMR. All mutants have modifications in the first calcium-binding site of calbindin (the N-terminal site designated the pseudo-EF-hand). The 3D structure of the mutant with the most extensive modifications in the pseudo-EF-hand shows that the site has turned inside-out and coordinates calcium as in the normal EF-hand (the C-terminal site). In a pseudo-EF-hand loop the calcium is coordinated by main-chain carbonyls, whereas calcium in the normal EF-hand is coordinated by side-chain carboxylates. The 3D structures and 1H NMR assignments show that in order to accomplish a change in the coordinating ligands of the pseudo-EF-hand the loop must be 12 residues long and have glycine in the sixth position. It does, however, seem possible to have alanine instead of aspartic acid in the first calcium coordinating position. The overall global fold of the proteins has not been affected by the mutations in the calcium-binding site, as compared to the wild-type calbindin D9k [Kördel, J., Skelton, N. J., Akke, M., & Chazin, W. J. (1993) J. Mol. Biol. (in press)]. The structures consist of two helix-calcium-binding loop-helix motifs, the so called EF-hands, and the loops are connected by a short antiparallel beta-sheet. All helices are pairwise in an antiparallel orientation.

Amino Acid Sequence↗
PubMed1993

CD44 is necessary for optimal contact allergic responses but is not required for normal leukocyte extravasation.

The in vivo administration of certain monoclonal antibodies (mAbs) against the adhesion receptor, CD44, into normal mice induces both a modulation of CD44 from the surface of peripheral lymphocytes, and a concomitant increase in the amount of soluble CD44 in the serum. CD44-negative lymphocytes isolated from anti-CD44-treated mice exhibit normal homing patterns upon adoptive transfer, and are capable of reexpressing CD44 upon activation. The treatment of haptensensitized mice with anti-CD44 mAb inhibits their ability to mount a cutaneous delayed-type hypersensitivity (DTH) response within the first 24 h after hapten challenge. This inhibition reflects a block in both the edema and leukocyte infiltration of the cutaneous site of DTH, whereas the extravasation and accumulation of leukocytes in the draining lymph nodes progress normally. After 72 h, the leukocytes that extravasate into the site of antigen challenge express CD44. These results indicate that CD44 is not necessary for normal leukocyte circulation but is required for leukocyte extravasation into an inflammatory site involving nonlymphoid tissue.

Animals↗
PubMed1993

Knee function after anterior cruciate ligament ruptures treated conservatively.

Thirty-nine patients with ruptures of the anterior cruciate ligament (ACL) were treated conservatively and were subsequently examined at an average of 5.7 years after injury, the uninjured leg acting as a control. The Tegner activity score was significantly lower than the desired activity level. No patients were free of symptoms and only two could take part in sport which involved pivoting. The isokinetic knee extensor and flexor torques, as well as the one-leg-hop and instrumented knee joint laxity tests, were significantly impaired at follow-up. Functional impairment was not related to tests of knee joint laxity. Few patients were pleased with their subjective knee function after an ACL rupture despite thorough initial rehabilitation.

Acute Disease↗