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Biomedical subjects

A Johansson

Publications and source records attributed to A Johansson.

At least 163 records · Page 9Linked to original sources
PubMed1997

In situ freezing of the rabbit and rat brain.

We have measured the effectiveness of different standard cryogenic liquids (liquid nitrogen, chilled isopentane, chilled hexane, and chilled ethanol) and applied a mathematical model for calculating the temperature changes at different depths in rabbit and rat heads cooled in liquid nitrogen. We have also evaluated the extent to which the freezing time is shortened when the skin is removed prior to immersion. We conclude that: (i) of the coolants used, liquid nitrogen gives the most rapid freezing. (ii) dry ice-chilled ethanol is as effective as dry ice-chilled hexane. Liquid nitrogen and ethanol are safer for the environment than isopentane and hexane and should satisfy most needs. (iii) By removing the skin prior to immersion, the freezing time can be reduced by about 20 s for the rabbit cortex and rat hypothalamus, 30 s for the rat cortex, and 40 s for the rabbit hypothalamus.

Animals↗
PubMed1997

In vitro interaction of alveolar macrophages and Aspergillus fumigatus.

In vitro interaction of alveolar macrophages (AM) from rats with conidia from Aspergillus fumigatus and Aspergillus candidus as well as inert control particles (amorphous silica) of similar diameter (about 3 microns), was studied. Experimental observations showed that both kinds of conidia were phagocytized significantly faster by AM than were the control particles due to a faster rate of attachment, but even more so due to a faster rate of ingestion. Quantitative nitroblue tetrazolium reduction by AM reflecting their oxidative metabolism and oxygen radical release was increased in response to both kinds of conidia by a factor of 2-3 during the process of phagocytosis, as well as 24 hr after the onset of phagocytosis, compared to corresponding conditions with inert particles and to resting macrophages. The mean pH in phagolysosomes with each of the conidia tended to be higher after 3 hr but was significantly lower after 24 hr than in the phagolysosomes with the control particles. After 3 hr there was a considerable percentage (around 8%) of phagolysosomes with pH > or = 6.5 and after 24 hr there was still a small percentage (0.7%) of such phagolysosomes for each of the conidia. Such a fraction was not observed for the control particles. Electron microscopic studies showed passages between phagolysosomes and AM surface with both kinds of conidia. The occurrence of such unsealed phagolysosomes might explain the percentage of phagolysosomes with high pH. Hence, Aspergillus conidia in unsealed macrophage vacuoles mediate an increased oxygen radical release from the macrophages, a process which in the long run might cause lung damage.

Animals↗
PubMed1997

Cell and soft tissue interactions with methyl- and hydroxyl-terminated alkane thiols on gold surfaces.

In order to evaluate the biological response induced by true methyl and hydroxyl surfaces, alkane thiols were immobilized onto gold. Initial protein adsorption from human plasma was measured in vitro by ellipsometry-antibody techniques and in vivo surface-cell interactions were evaluated in rat subcutaneous tissues for time periods ranging between 1 and 28 days. Rat mononuclear cells were studied after culturing (24 h) on the surfaces. Plasma protein experiments revealed deposition of fibrinogen onto the pure gold and the methylated surface. The hydroxylated surface tended to release the surface-associated proteins tested for by antibodies. None of the in vivolin vitro models used showed differences between the hydroxyl and methyl surfaces for spontaneous or augmented cell hydrogen peroxide and interleukin-1 alpha secretions. However, the different surface chemistries markedly affected the distribution of the cells that were recruited to the interfaces (cells in the fluid space and surface-associated DNA content on the retrieved implants) at late and early time periods. The results indicate that different implant surface properties, such as chemical functionality and hydrophobicity, influence specific events in the inflammatory cell response, and ultimately the wound healing around implantable materials.

Alkanes↗
PubMed1997

In vivo interaction between alveolar macrophages and Cryptococcus neoformans.

In vivo interactions of rabbit alveolar macrophages (AM) and Cryptococcus neoformans, a yeast pathogenic for humans, were studied. As a control, inert silica particles of a similar diameter (5-6 microns) were used. Of 16 rabbits, 6 were instilled intratracheally with fluorescein-labelled heat-killed C. neoformans, 6 with fluorescein-labelled silica particles and 4 with saline only. After 24 h, the AM were collected by lung lavage, and phagocytosis, oxidative metabolism, phagolysosomal pH and morphology were studied. The accumulated number of yeasts attached to the AM was almost the same for C. neoformans as for the silica particles. The ingested fraction of C. neoformans was even higher than that of the silica particles. Quantitative NBT reduction by the AM, reflecting their oxidative metabolism, was markedly increased by exposure to C. neoformans for 24 h. The phagolysosomal pH was on the average lower in phagolysosomes with C. neoformans than with the silica particles, although approximately 2% of the phagolysosomes with C. neoformans had neutral pH. Phagolysosomes with neutral pH was not observed for silica particles. Electron microscopy showed presence of C. neoformans in phagolysosomes of AM. The conclusion of this study is that the phagocytic activity, oxidative metabolism and phagolysosomal pH AM against C. neoformans are significant 24 h after the exposure.

Animals↗
PubMed1997

Alveolar macrophage reaction to Candida species.

Candida species are increasingly important fungal pathogens. The reaction of rat alveolar macrophages (AM) to Candida albicans was compared with that to C. glabrata and C. krusei. Phagocytosis of C. glabrata was similar to that of C. albicans, but significantly slower for C. krusei due to reduced attachment. After opsonization, attachment of C. albicans and C. krusei to AM was significantly increased and there was no significant difference between the two species. The oxidative metabolism of AM with candida species was two to three times higher than that of the resting AM both during and 24 h after the phagocytosis. All three species showed a considerable fraction (5-10%) of phagolysosomes with pH > or = 6.5 after 3 h and a smaller percentage (1%) after 24 h.

Animals↗
PubMed1997

Annual risk for the first hemorrhage from untreated cerebral arteriovenous malformations.

To estimate the annual risk for the first hemorrhage, survival and life table statistics were used to analyze data from 2262 patients with cerebral arteriovenous malformations (AVM). We found that the risk for hemorrhage increases with increasing age. A validity test revealed, however, that life table statistics used on the total patient material underestimated the annual risk for hemorrhage, especially for patients 20-50 years of age. A method based on the fact that the distribution of the time at risk until the initial hemorrhage (= age at first rupture) reflects the risk for hemorrhage in untreated AVM was therefore also employed. The analysis yielded three conclusions: 1) the annual risk of hemorrhage increases with age; 2) small AVM are less prone to rupture; and 3) the risk of hemorrhage is higher in women during their fertile years as compared to males in the same age group. The risk related to age, AVM size and location assessed by survival statistics in the subgroup of patients with a known date for the initial hemorrhage gave similar results.

Adolescent↗
PubMed1997

Detection of joint pathology by magnetic resonance imaging in patients with early rheumatoid arthritis.

Magnetic resonance imaging (MRI) permits the visualization of anatomical structures not appreciated by conventional radiographic imaging, and may assess inflammatory disease and its progression with greater sensitivity than conventional radiography. In this study of 30 patients with early rheumatoid arthritis (RA), which could be considered as a pilot study because of the relatively small number of patients, we compare MRI of the knee and the fifth metatarsophalangeal joint with clinical and radiographic findings. A parallel study of 10 healthy individuals served as a reference group. In all but one of the 30 patients, MRI revealed some kind of joint abnormality, whereas conventional radiography was normal in 14 patients. The present study thus suggests that MRI may detect inflammatory and/or destructive joint changes in patients with early RA, and that these changes may occur in the absence of clinical symptoms or signs and/or radiographic signs in the examined joint. If these data prove to be confirmed in further controlled studies, MRI may be of importance both for the assessment of prognosis and for the decision to treat in the early critical stages of RA.

Adult↗
PubMed1997

Reduced hospitalization with cardiovascular and pulmonary disease in obstructive sleep apnea patients on nasal CPAP treatment.

Cardiovascular and pulmonary disease (CVPD) is common in patients with obstructive sleep apnea syndrome (OSAS). This retrospective study addressed the accumulated in-hospital time during 2 years prior to treatment with nasal continuous positive airway pressure (nCPAP) as compared to 2 years after initiating of nCPAP in patients with OSAS and CVPD. A cohort representing all patients (n = 88) receiving nCPAP during the period 1988-1994 at the Skövde Central Hospital, Skövde, Sweden, was studied. Data collection was based on interviews with patients as well as reviews of clinic charts. All hospitalizations and diagnostic codes by any type were thereby successfully gathered for the whole group. Six patients with confounding serious diseases were excluded from the analysis. A CVPD diagnosis (ICD-9, codes 401-435 and 490-496) was found in 54 out of 82 patients (66%), of whom 36 of 58 were nCPAP users (62%) and 18 of 24 were nonusers (75%). In 54 sleep apneics with CVPD, 31 were hospitalized acutely under one or more of these diagnostic codes during the study period of 4 years. The total number of in-hospital days due to CVPD in the nCPAP users (n = 19) before nCPAP prescription was 413 days (median 10, range 3-66) compared to 54 days (median 0, range 0-25) after nCPAP (p < 0.0001). The corresponding values for the nonuser group (n = 12) was 137 days (median 8.5, range 0-42) before and 188 days (median 9.5, range 0-47) after the nCPAP prescription (ns). We conclude that nCPAP treatment reduces the need for acute hospital admission due to CVPD in patients with OSAS. This reduction of concomitant health care consumption should be taken into consideration when assessing the cost-benefit evaluation of nCPAP therapy.

Aged↗
PubMed1997

Functional, morphological, and phenotypical differences between rat alveolar and interstitial macrophages.

Alveolar macrophages (AM) and interstitial macrophages (IM) from rat lungs were characterized with respect to morphology, phagocytosis, adhesion properties, and phenotype. AM were recovered by lung lavage and IM by treatment of the lung tissue with DNAse and collagenase. The AM were enzyme treated in the same way as the IM. The IM were smaller than AM and had a higher nuclear to cytoplasm ratio. They had markedly lower phagocytic capacity. The attachment of particles to the cell surface was significantly lower in IM than in AM, but the capacity to ingest the particles was the same. Adherence to vitronectin- as well as fibronectin-coated surfaces was significantly higher in AM. The phagolysosomal pH was similar in IM and AM, around pH 5, indicating that dissolution of inorganic particles can take place effectively also in IM. Five surface receptors were studied, and the expression differed significantly in all five between AM and IM. The expression of OX-1 (CD 45), a common leukocyte antigen, was significantly higher on AM as was the expression of CD 71 (transferrin receptor). The receptor density for OX-42 was higher on a fraction of IM. This might be compatible with a stronger interaction between these cells and, for example, matrix components. IM had more surface antigen expressing MHC class Ia (OX-6) and CD 54. Both receptors are important for the antigen presentation capacity of macrophages. These findings show profound differences in phenotype between AM and IM and indicate that IM is a highly immunocompetent cell and should not be regarded only as a precursor to AM.

Animals↗
PubMed1997

Circulating non-22-kilodalton growth hormone isoforms in acromegalic men before and after transsphenoidal surgery.

GH represents several molecular isoforms in addition to the main 22-kDa (22K) GH. There have been reports suggesting that circulating non-22K GH isoforms are increased in acromegaly, but the possible implications of such observations in the management of the disease have not been addressed. The aim of this study was to evaluate the proportion of circulating non-22K GH isoforms in acromegaly. In addition, the relationships between the amount of non-22K GH and tumor size, biochemical measurements, and body composition also were investigated. Samples with different GH levels were selected from 24-h GH profiles from 15 acromegalic men evaluated before and 1 yr after transsphenoidal surgery and from 13 healthy men. The serum non-22K GH levels, expressed as percentage of total GH concentration, were determined by the 22K GH exclusion assay, which is based on immunomagnetic extraction of 22K GH from serum and quantitation of non-22K GH using a polyclonal GH assay. The proportion of non-22K GH isoforms was fairly constant in different samples from the same patient, regardless of the GH level. However, a wide variation of values was observed among acromegalics, both before (14-51%) and after surgery (8-62%). The proportion of non-22K GH isoforms was increased in untreated patients, compared with controls (26.6 vs. 17.4%; P < 0.01), and the values correlated significantly to tumor size, mean 24-h GH concentration, serum PRL, and extracellular water. After surgery, patients not truly cured, with mean 24-h GH concentration of 1 microg/L or more, had an increased proportion of non-22K GH, compared with those with levels less than 1 microg/L (P < 0.01). In the former group, the median values were similar than those in untreated acromegalics (34 vs. 26.6%, respectively), whereas in the latter, they were comparable with those in the controls (15.2 vs. 17.4%, respectively). We conclude that acromegalics have an increased proportion of circulating non-22K GH isoforms. The values are fairly constant in different samples from an individual, regardless of GH level, but a large spectrum can be observed among patients. This variability suggests that different pituitary adenomas secrete GH isoforms in variable amounts. Our observation that a higher proportion of non-22K GH isoforms is present in patients not truly cured after surgery suggests that the evaluation of non-22K GH isoforms can be useful in the follow-up of acromegalic patients.

Acromegaly↗
PubMed1997

Dental erosion associated with soft-drink consumption in young Saudi men.

This study reports on the causative factors of dental erosion in selected high- (n = 19) and low-erosion (n = 19) subgroups of a larger random sample (n = 95) of young male Saudi military inductees. By means of a questionnaire, the role of various possible factors related to oral health in general, and to dental erosion in particular, was assessed for each participant. Clinical examination included recordings of severity of dental erosion and fluorosis, presence of buccal cervical defects and first permanent molar 'cuppings', DMFT and DMFS, visible plaque index, and gingival bleeding index. In addition, bitewing radiographs, study casts, and intraoral color transparencies were obtained for each individual. Logistic regression analysis showed a strong correlation between the presence of dental erosion and a high level of consumption of cola-type soft drinks. Other statistically significant associated factors, although of less predictive strength, were type of cleaning aid and gingival bleeding index. In subgroup comparisons, dental problems (primarily pain), number of buccal cervical defects, and number of missing teeth were significantly greater in the high- than in the low-erosion subgroup.

Adult↗
PubMed1996

Child spacing and two child policy in practice in rural Vietnam: cross sectional survey.

OBJECTIVE: To explore the reproductive pattern of women in rural Vietnam in relation to the existing family planning policies and laws. DESIGN: Cross sectional survey with question-naires on reproductive history. SETTING: Tien Hai, a district in Red River Delta area, where the population density is one of the highest in Vietnam. SUBJECTS: 1132 women who had at least one child under 5 years of age in April 1992. MAIN OUTCOME MEASURES: Birth spacing and probability of having a third child. RESULTS: The mean age at first birth was 22.2 years. The average spacing between the first and the second child was 2.6 years. Mothers with a lower educational level, farmers, and women belonging to the Catholic religion had shorter spacing between the first and second child and also a higher probability of having a third child. In addition, women who had no sons or who had lost a previous child were more likely to have a third child. CONCLUSION: Most families do not adhere to the official family planning policy, which was introduced in 1988, stipulating that each couple should have a maximum of two children with 3-5 years' spacing in between. More consideration should be given to family planning needs and perceptions of the population, supporting the woman to be in control of her fertility. This may imply improved contraceptive services and better consideration of sex issues and cultural differences as well as improved social support for elderly people.

Age Factors↗
PubMed1996

Population policies and reproductive patterns in Vietnam.

BACKGROUND: Vietnam's population policy since the 1980s had stipulated a limit on family size to two children, born 3-5 years apart, and recommends a minimum age of 19 for the mother of a first child. We analysed trends in the timing of marriages and births, and in fertility and abortion rates, among women born between 1945 and 1970, to assess the impact of these policies on reproductive patterns. METHODS: Reproductive histories were recorded in a random sample of 1432 married women aged 15-49 in a rural province in northern Vietnam. Mean age at marriage and at birth of the first child, birth intervals, fertility, and abortion rates were examined in relation to the woman's year of birth. FINDINGS: Later-born women married and had their first child at a younger age than women born earlier. Birth intervals had increased among later-born women but 25% still had only a 1-year interval between first and second child. Fertility had gradually decreased while abortion ratios had increased rapidly. Childbearing patterns had become "earlier, longer, and fewer" rather than "later, longer, and fewer" as stipulated by the policies. The results also show that women with more schooling married and had their first child later. Women involved in farming had shorter spacing between children. INTERPRETATION: There are signs that Vietnam's population policy has focused too strongly on contraception and abortion while ignoring the connection between fertility and women's opportunities for education and employment. In these respects, rural women are at particular risk.

Abortion, Induced↗
PubMed1996

Toxic effects of some conifer resin acids and tea tree oil on human epithelial and fibroblast cells.

The present study was undertaken to assess and compare the in vitro cytotoxic effects of three resin acid analogues: dehydrobietic acid, podocarpic acid, O-methylpodocarpic acid; an essential oil from Australia (tea tree oil); and tapped oleoresin from Thailand, on human epithelial and fibroblast cells, using a quantitative neutral red spectrophotometric assay. All of the investigated compounds except for tea tree oil exhibited a cytotoxic activity which was proportional to their concentrations and time of exposure up to 24 h, i.e. higher concentrations and longer time of exposure caused increased cell death. Dehydroabietic acid and the oleoresin were the most toxic compounds followed by O-methylpodocarpic acid, whereas podocarpic acid and tea tree oil showed a lower level of toxicity. On the basis on these findings it is concluded that an isopropyl group on the aromatic C-ring is of great importance for the cytotoxicity of the tested abietane resin acids, thus indicating that the cytotoxic activity of oleoresins most probably is caused by synergistic or additive effects of resin acids. The results from this work support the view that antibacterial activity parallels cytotoxic activity which suggests a similar mode of action, most probably exerted by membrane-associated reactions.

Abietanes↗
PubMed1996

Existence of phosphorylated and dephosphorylated forms of cytosolic thymidine kinase (TK1).

In this study we examine whether different TK1 variants of pI 6.9 and 8.3 found by isoelectric focusing gel electrophoresis (IFE) reflect just a phenotype difference due to phosphorylation modifications or have a real phenotypic background. The phosphorylation degree of purified TK1 variants was analyzed by determining the changes in the pI values after treatment with alkaline phosphatase, using IFE. The genetic origin of the two TK1 variants was studied by determining their mol wt. by means of SDS-gelelectrophoresis. Furthermore, the subcellular distribution of the two TK1 variants was also studied. Alkaline phosphatase treatment changed the pI value of purified TK1 from 6.9 to 8.3. No change in the pI value was found when purified TK1 corresponding to pI 8.3 was treated in the same way. Similar results were obtained when treated a cytosolic fraction with alkaline phosphatase. Antibody raised against the C-terminal part of human TK1 only recognized the dephosphorylated TK1 variant corresponding to pI 8.3. There was no difference in the molecular weight between the two TK1 variants. Thus, we concluded that the TK1 variants corresponding to pI 6.9 and 8.3 are of the same genetic origin, but consist of phosphorylated and dephosphorylated forms.

Animals↗
PubMed1996

An experimental model of cerebral microischemia in rabbits.

Multiinfarct dementia is the second most common form of dementia in the elderly. An animal model of microischemia may provide information about the pathophysiology relevant when searching for prevention or treatment of microinfarctions in humans. The purpose of the present study was to develop an experimental model useful for studying discrete microischemic foci. In order to achieve single cerebral microischemic foci plastic beads with diameters of about 100 microns were injected into the left heart ventricle of anesthetized rabbits. 2-Deoxy-[14C]glucose (2-DG) and autoradiography were used to detect regions with disturbed metabolism. The tissue sections were inspected for impacted beads. Foci with markedly increased 2-DG accumulation and with diameters of about 1 mm were detected in all parts of the brain, indicating hypoxic regions with enhanced glycolysis. In some foci, located mainly in the basal ganglia, a central dip in the 2-DG profile was seen, suggesting poor glucose supply to the central ischemic region. The ratio foci/beads was about 1 in the brain stem (diencephalon included) and about 0.5 in the cortex. Twenty-four hours after embolization, infarctions, mainly in the deeper brain regions, were seen. There were still foci with increased 2-DG uptake, which were mainly located in the cortex. The results suggest that microemboli reaching the deeper brain regions give rise to metabolic disturbances more often than emboli reaching the cortex and that the ischemic foci in deeper brain regions are more prone to develop further into infarctions.

Animals↗
PubMed1996

Nerve blocks with local anesthetics and corticosteroids in chronic pain: a clinical follow-up study.

During 4 years, 45 patients with various chronic pain conditions were treated with nerve blocks in our clinic. The blocks consisted of injections of local anesthetic and a corticosteroid on one or several occasions. At the end of this time period, the patients' pain was classified from their records as nociceptive, neurogenic, or unknown, according to International Association for the Study of Pain (IASP) criteria. The long-term treatment results were evaluated retrospectively with a questionnaire. Twenty-nine patients had neurogenic pain, 11 patients had nociceptive pain, and, in the remaining 5 patients, the type of pain could not be determined. Only 6 of the 45 patients had pain relief for longer than 1 month. It is concluded that treatment with nerve blocks alone is not very effective as a long-term treatment for chronic pain. Further experimental and systematic clinical studies are necessary to define the ultimate place for nerve blocks in the treatment of chronic nonmalignant pain.

Adolescent↗