Biomedical subjects

B Johansson

Publications and source records attributed to B Johansson.

At least 235 records · Page 13Linked to original sources

PubMed1997

Translocations between the long arms of chromosomes 1 and 5 in hematologic malignancies are strongly associated with neoplasms of the myeloid lineages.

The clinical, morphologic, and cytogenetic features of two hematologic malignancies--one acute myeloid leukemia with minimal differentiation (AML-MO) and one therapy-related myelodysplastic syndrome (MDS)--with unbalanced translocations between 1q and 5q are reported. The translocations resulted in loss of 5q material in both cases and gain of 1q in the MDS. A compilation of previously published hematologic malignancies with translocations involving the long arms of chromosomes 1 and 5 revealed a total of 23 cases--11 with unbalanced and 12 with balanced t(1;5)--with the following morphologies: 11 AML, three MDS, two Philadelphia-positive chronic myeloid leukemias, three chronic myeloproliferative disorders, three acute lymphoblastic leukemias, and one chronic lymphocytic leukemia. Four patients had received chemotherapy including alkylating agents for a previous malignancy and one had been exposed to thorotrast. Among the 14 patients for whom survival data exist, all except three have died. The t(1;5) was found as the sole abnormality in six cases, whereas it was apparently secondary--occurring in a subclone or together with the well-known primary abnormalities t(8;21), t(9;22), and t(15;17)--in nine cases. The breakpoints in 1q varied from 1q11 to 1q43, with a clustering to 1q21-23, and the 5q breaks occurred in 5q11 to 5q35, mainly in the distal 5q3 region. The unbalanced 1;5 translocations resulted in gain of 1q material in eight of the 11 cases, 1q21-1qter being duplicated in four of them, and in loss of 5q, most often the 5q3 region, in 10 of the neoplasms. We conclude that translocations between 1q and 5q, although cytogenetically heterogeneous, are associated with hematologic malignancies of the myeloid lineages and with previous mutagenic exposure, and that t(1;5) seems to confer a poor prognosis.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Distribution and postnatal ontogeny of adenosine A2A receptors in rat brain: comparison with dopamine receptors.

In adult rat brain, adenosine A2A receptors and dopamine D2 receptors are known to be located on the same cells where they interact in an antagonistic manner. In the present study we wanted to examine when this situation develops and compared the postnatal ontogeny of the binding of the adenosine A2A receptor agonist [3H]CGS 21680, the binding of the dopamine D1 receptor antagonist [3H]SCH 23390 and the dopamine D2 receptor antagonist [3H]raclopride. All three radioligands bound to the striatum at birth and this binding increased several-fold during the postnatal period. [3H]SCH 23390 binding developed first (mostly during the first week), followed by [3H]raclopride binding (first to third week) and [3H]CGS 21680 binding (only during second and third week). For all three radioligands the binding tended to decrease between 21 days and adulthood. This occurred earlier and was more pronounced in the globus pallidus than in the other examined structures. The increase in [3H]CGS 21680 binding from newborn to adult was mainly due to four-fold increase in the number of binding sites. The pharmacology of [3H]CGS 21680 binding to caudate-putamen was similar in newborn, one-week-old and adult animals, and was indicative of A2A receptors. The binding was inhibited by guanylyl imidodiphosphate at all ages, indicating that A2A receptors are G-protein-coupled already at birth. In contrast to the large increase in [3H]CGS 21680 binding, there was a decrease in the levels of A2A messenger RNA during the postnatal period in the caudate-putamen. In cerebral cortex [3H]CGS 21680 bound to a different site than the A2A receptor. From birth to adulthood cortical binding of [3H]CGS 21680 increased four-fold and that of the adenosine A1 agonist [3H]cyclohexyladenosine 19-fold. During early postnatal development [3H]SCH 23390 binding was higher in deep than in superficial cortical layers, but this difference disappeared in adult animals. There was binding of both [3H]CGS 21680 and [3H]cyclohexyladenosine to the olfactory bulb, suggesting a role of the two adenosine receptors in processing of olfactory information. [3H]CGS 21680 binding was present in the external plexiform layer and glomerular layer, and increased during development, but the density of binding sites was about one tenth of that seen in caudate putamen. [3H]cyclohexyladenosine showed a very different labelling pattern, resembling that observed with [3H]SCH 23390. Postnatal changes in adenosine receptors may explain age-dependent differences in stimulatory caffeine effects and endogenous protection against seizures. Since A2A receptors show a co-distribution with D2 receptors throughout development, caffeine may partly exert such actions by regulating the activity of D2 receptor-containing striatopallidal neurons.

Adenosine↗

PubMed1997

ACE inhibition by enalaprilate stimulates duodenal mucosal alkaline secretion via a bradykinin pathway in the rat.

The effects of enalaprilate on duodenal mucosal alkaline secretion (in situ titration) and mean arterial blood pressure were investigated in chloralose-anesthetized male rats. A bolus injection of enalaprilate (0.7 mg/kg intravenously) increased alkaline secretion by about 60%, and this response was resistant to guanethidine (5 mg/kg intravenously), splanchnicotomy, and vagotomy. Furthermore, angiotensin II infusion (0.25-2.5 microg/kg/hr intravenously) following the administration of enalaprilate failed to influence this response. Bradykinin (10(-6)-10(-4) M) applied topically to the serosal surface of the duodenal segment under study increased dose-dependently the duodenal mucosal alkaline secretion, an effect that could be blocked by the selective bradykinin receptor subtype-2 antagonist HOE140 (100 nmol/kg intravenously). HOE140 also antagonized the response to enalaprilate. These data suggest that enalaprilate increases duodenal mucosal alkaline secretion via a local bradykinin pathway involving receptors of the bradykinin receptor subtype-2 antagonist, rather than by blockade of endogenous angiotensin II or by central autonomic neural regulation.

Adrenergic beta-Antagonists↗

PubMed1997

Cytogenetic comparisons of synchronous carcinomas and polyps in patients with colorectal cancer.

Thirty tumorous lesions from seven patients with colorectal cancer were short-term cultured and cytogenetically analysed: 16 non-adenomatous polyps, six adenomas, seven carcinomas, including one in polyp, and one lymph node metastasis. Clonal chromosome aberrations were found in 20 samples in 100% of the carcinomas, in 100% of the adenomas and in 37.5% of the non-adenomatous polyps, i.e. all ten lesions with a normal karyotype were histologically diagnosed as hyperplastic polyps. Although adenomas and carcinomas shared several karyotypic features, two chromosome aberrations, der(8;17)(q10;q10) and -14, were found in carcinomas but not in adenomas, indicating that they might be specifically associated with carcinoma development in the large bowel mucosa. The karyotypic similarity seen between the malignant and benign tumours in the same patient, and also sometimes among non-malignant polyps in the same case, indicates that these microscopically distinct lesions may be part of a single neoplastic clonal expansion.

Adenoma↗

PubMed1997

A breakpoint map of recurrent chromosomal rearrangements in human neoplasia.

Cytogenetic studies over the past few decades have revealed clonal chromosomal aberrations in almost 27,000 human neoplasms. Many of these neoplasia-associated chromosomal abnormalities have been characterised at the molecular level, revealing previously unknown genes that are closely associated with the tumorigenic process. Information on chromosome changes in neoplasia is growing rapidly, making it difficult to identify all recurrent chromosomal aberrations. We have developed a computer program to ascertain, for the first time, all recurrent structural abnormalities in all haematological malignancies and solid tumours published up to June 1996. Out of 26,523 cases, a total of 215 balanced and 1,588 unbalanced recurrent aberrations were identified among 75 different neoplastic disorders. Our compilation of all recurrent balanced and unbalanced neoplasia-associated rearrangements should help in directing future efforts aimed at identifying the molecular mechanisms involved in tumorigenesis.

Chromosome Aberrations↗

PubMed1997

Deletion of chromosome arm 3p in hematologic malignancies.

Cytogenetic aberrations resulting in deletion of 3p are common in solid tumors, indicating the presence of tumor suppressor genes (TSG) on this chromosome arm. The present study was undertaken to investigate 3p loss in hematologic disorders. Ten acute myeloid leukemias (AML), two myelodysplastic syndromes (MDS), one Philadelphia chromosome-positive chronic myeloid leukemia (CML), three acute lymphoblastic leukemias (ALL), one chronic lymphoproliferative disorder (CLD), and three non-Hodgkin's lymphomas (NHL) with abnormalities leading to 3p deletions were identified, constituting 2.9% of AML, 0.7% of MDS, 1.0% of CML with changes in addition to t(9;22), 1.5% of ALL, 4.2% of CLD, and 1.1% of NHL with cytogenetic abnormalities analyzed at our Department. Among 19042 karyotypically aberrant published cases, 1.2% of 6260 AML, 1.3% of 2285 MDS, 0.8% of 840 chronic myeloproliferative disorders (CMD), 0.7% of 1894 CML with additional aberrations to t(9;22), 0.6% of 3589 ALL 2.4% of 1602 CLD, 4.5% of 178 Hodgkin disease (HD), and 3.1% of 2394 NHL displayed partial loss of 3p (0.6-4.5%; P < 0.001); the majority occurring together with other abnormalities. The frequencies of 3p loss did not differ significantly among the MDS, ALL, and CLD morphologic subgroups, between B and T cell ALL, CLD, and NHL, among low-, intermediate-, and high-grade NHL, or between therapy-related MDS and de novo MDS, whereas the incidence of 3p deletions was higher in treatment-associated AML (P < 0.001) than in de novo AML and varied among the AML FAB groups (P < 0.001). The most frequently deleted chromosome bands were 3p25 in AML, 3p26 in MDS, 3p14 in CMD, 3p25, 3p23, and 3p21 in CML, 3p26 and 3p25 in ALL, 3p26 and 3p25 in CLD, 3p26 in HD, and 3p26 in NHL. These deletion hot spots are more distal than those reported in most solid tumor types, suggesting that different TSG are involved in hematologic malignancies and solid neoplasms.

Chromosome Aberrations↗

PubMed1997

Chemotherapy-related - late occurring - Philadelphia chromosome in AML, ALL and CML. Similar events related to treatment with DNA topoisomerase II inhibitors?

Therapy with DNA topoisomerase II inhibitors has been shown to result in an increased risk of acute myeloid leukemia (AML), often presenting balanced translocations to chromosome bands 11q23 and 21q22. Also other balanced aberrations, more rarely observed in therapy-related AML (t-AML), such as t(15;17) and inv(16) have been associated with these drugs. Recently we observed a case of chronic myeloid leukemia (CML) with t(9;22) after therapy of a germ cell tumor with etoposide, cisplatin and bleomycin. Based on this case and a review of chemotherapy-related leukemias with t(9;22) from the literature, we suggest a causal relationship between therapy with DNA topoisomerase II inhibitors and development of various types of leukemia carrying the Philadelphia chromosome.

Adolescent↗

PubMed1997

Acid-induced increase in duodenal mucosal alkaline secretion in the rat involves the L-arginine/NO pathway.

Duodenal mucosal alkaline secretion increases in response to hydrochloric acid exposure. The tentative role of nitric oxide (NO) in the mediation of this response was investigated. The mucosal alkaline output by a duodenal segment was recorded by in situ titration in chloralose-anaesthetized rats. In some experiments the duodenal blood flow was estimated by laser-Doppler flowmetry. Exposure of the duodenum to acid (0.01 M HCl, 5 min) increased the alkaline secretion by approximately 85%. The NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 10 mg kg-1 intravenously or 0.3 mM intraluminally) blocked the secretory increment after mucosal acid exposure. Mean arterial pressure and basal alkaline secretion were markedly raised, whereas duodenal blood flow was decreased, when L-NAME was given intravenously (i.v.). Intraluminal (i.l.) administration left mean arterial pressure as well as duodenal blood flow unaltered, and the duodenal mucosal alkaline secretion was only slightly elevated. The stereoisomer NG-nitro-D-arginine methyl ester (D-NAME) had no effect on either basal or acid-induced duodenal alkaline output. In animals receiving L-arginine (10 mg kg-1 min-1 i.v., or 3 mM i.l.) and L-NAME, the acid exposure elicited an increase in duodenal mucosal alkaline secretion, similar to that observed in controls. The results suggest that the acid-induced increase in duodenal mucosal alkaline secretion involves NO synthesis, which takes place close to the lumen, probably within the mucosa.

Animals↗

PubMed1997

Childhood acute lymphoblastic leukaemia with ider(21)(q10)t(12;21)(p12;q22): a new recurrent abnormality showing ETV6/CBFA2 fusion.

The cytogenetically unidentifiable t(12;21)(p12:q22), resulting in ETV6/CBFA2 fusion, is the most frequent chromosomal aberration in childhood acute lymphoblastic leukaemia ALL). We report a variant, ider(21)(q10)t(12:21)(p12;q22), which was shown to contain double ETV6/CBFA2 fusions by fluorescence in situ hybridization. This is the second case of such an ider(21) in childhood ALL, suggesting that it is a new recurrent abnormality. Since the ider(21) is cytogenetically indistinguishable from i(21)(q10) and idic(21)(p11), changes associated with similar clinical features as the t(12;21), i.e. pre-B-cell ALL and age 1-10 years, we suggest that all ALL displaying these changes should be tested for ETV6/CBFA2 fusion transcript.

Child↗

PubMed1997

Water extract of Helicobacter pylori inhibits duodenal mucosal alkaline secretion in anesthetized rats.

BACKGROUND & AIMS: The pathophysiology behind Helicobacter pylori-induced gastroduodenal dysfunction is incompletely understood. The aim of this study was to investigate if a water extract of H. pylori distorts acid-induced duodenal mucosal alkaline secretion. METHODS: Chloralose-anesthetized rats were prepared for duodenal luminal perfusion and in situ pH-stat titration of mucosal alkaline secretion. RESULTS: Mucosal bicarbonate secretion increased approximately 55%-60% after a 5-minute exposure to 10 mmol/L HCl. This response was absent when water extracts of three strains of H. pylori (protein content, 0.2-20 microg/mL) had been added to the perfusate. Presence of 3 mmol/L L-arginine, but not the stereoisomer D-arginine, in the luminal perfusate reversed the H. pylori extract blockade of acid-induced mucosal alkaline secretion. High-performance liquid chromatography-based analyses showed that the endogenous nitric oxide synthase inhibitor asymmetric dimethyl arginine (ADMA) increased fourfold in duodenal perfusate and fivefold in duodenal tissue after H. pylori extract exposure. In vitro proteolysis of H. pylori extract also resulted in a substantial accumulation of ADMA. Exogenously administered ADMA, giving similar tissue concentrations, inhibited the mucosal alkaline response to acid exposure. CONCLUSIONS: Water extracts of H. pylori inhibit acid-induced mucosal alkaline secretion via interference with mucosal NO synthase.

Anesthesia↗

PubMed1997

General collection efficiency for liquid isooctane and tetramethylsilane used as sensitive media in a parallel-plate ionization chamber.

The general collection efficiency has been measured in liquid isooctane (C8H18) and tetramethylsilane (Si(CH3)4) used as the sensitive media in a parallel-plate ionization chamber, with an electrode distance of 1 mm, intended for photon and electron dosimetry applications. The liquid ionization chamber was irradiated at different dose rates by 140 keV photons from the decay of radioactive 99mTc. The measurements were made at potential differences of 50, 100, 200 and 500 V. Measurements were performed for each liquid and electric field strength, with the decay rate of 99mTc used as the dose-rate reference. The maximum dose rate was about 150 mGy min-1 in each experiment. When the measured general collection efficiency values are compared with the theoretical predictions for collection efficiency in gases, it is found that the latter also describe the general collection efficiency in the two liquids within 1% of the saturation current for collection efficiencies down to 60% when using experimentally determined recombination rate constants and on mobilities characteristic of each of the liquids.

Half-Life↗

PubMed1997

General collection efficiency for liquid isooctane and tetramethylsilane in pulsed radiation.

The general collection efficiency in pulsed radiation was studied for isooctane (C8H18) and tetramethylsilane (Si(CH3)4). These two liquids were used as sensitive media in a parallel-plate liquid ionization chamber with a 1 mm sensitive layer. Measurements were carried out using 20 MV photon radiation from a linear accelerator with a pulse repetition frequency of 30 pulses/second and a pulse length of 3.5 microseconds. The general collection efficiency was determined for polarizing voltages in the interval 1000-2000 V for isooctane and 500-2000 V for tetramethylsilane and for pulse doses in the interval 0.06-1.9 mGy/pulse. An air ionization chamber was used as a pulse dose reference monitor. The experimental results were compared with those predicted by the equation for the general collection efficiency for gases in pulsed radiation, using the permittivity of each of the liquids. It was found that for general collection efficiencies down to 80% the differences between the predicted and experimental general collection efficiencies in the two liquids were within +/- 1% at electric field strengths exceeding 10(6) V m-1.

Octanes↗

PubMed1997

Heritability for Alzheimer's disease: the study of dementia in Swedish twins.

BACKGROUND: Alzheimer's disease has been thought to have familial and sporadic forms, and several genetic defects have been identified that chiefly explain early-onset familial cases. In this study, our purpose was to detect all cases of dementia in an established twin registry and to estimate total extent of genetic contribution to liability to Alzheimer's disease. METHODS: At the first stage, members of the registry were screened for dementia, using in-person or telephone mental status testing. At the second stage, those who screened positively and their partners were referred for clinical work-ups, including neuropsychological assessment, physician examination, laboratory tests, and neuroimaging. Clinical diagnoses were assigned at a multidisciplinary consensus conference. Probandwise concordance rates were examined by zygosity, and structural modeling was applied to the data to estimate genetic and environmental influences, using both single- and multiple-threshold models. RESULTS: Sixty-five pairs were identified in which one or both was demented. The probandwise concordance rate for Alzheimer's disease among monozygotic pairs was 67%; the corresponding figure for dizygotic pairs was 22%. Heritability of liability to Alzheimer's disease was estimated to be .74; to any dementia, .43. The other variance is attributable to environmental influences. CONCLUSIONS: Findings indicate a substantial genetic effect for these predominantly late-onset Alzheimer's disease cases. At the same time, structural modeling results and large intra-pair differences in age of onset suggest that environmental factors are also important in determining whether and when an individual may develop dementia.

Age of Onset↗

PubMed1997

Self-reports on memory functioning in a longitudinal study of the oldest old: relation to current, prospective, and retrospective performance.

Self-evaluation of memory performance, one aspect of metamemory, may be an important indicator of concurrent, retrospective, or future decline in memory functioning. The relationships among self-evaluations, cognition, and outcome were investigated in the OCTO study, a longitudinal, population-based panel of the oldest old. Using concurrent data, results indicated that overall cognitive ability, depression, gender, and education were associated with self-reports of memory for the entire sample. The relation of perception of decline to actual decline was also examined. Self-reported decline over a 2-year period was associated with actual decline in performance on three tests of memory. Finally, self-reported memory function was investigated as an indicator of future cognitive decline and diagnosis of dementia. These self-evaluations predicted decline on specific tests of memory over 2 years and subsequent diagnosis of dementia after 2 and 4 years. The amount of variance accounted for by self-evaluations, however, was relatively small, suggesting that complaints reflect different processes, only one of which is the pathological decline involved in dementia.

Aged↗

PubMed1997

Predicting change in activities of daily living: a longitudinal study of the oldest old in Sweden.

We examined predictors of stability and decline in activities of daily living (ADLs) and mobility in a population-based sample of the oldest old. Respondents were people aged 84 to 90 living in South Central Sweden. Predictors were drawn from three domains: sociodemographic variables, vitality, and physical and psychological health. Using a logistic regression model, we sought to identify variables that were associated with changes in functioning. Over the 2-year interval, we found significant main effects for stability in ADL functioning for three variables: residential status (e.g., living in the community), subjective health, and mastery (n = 142). For mobility, we identified three variables associated with stability: lung function, subjective health, and mastery (n = 137). Over the 4-year period we found that residential status was significantly associated with stability in ADL performance (n = 89), while age, marital status, grip strength, and mastery were significant predictors for stability in mobility (n = 90). The findings can direct researchers toward interventions within particular residential environments that maintain a sense of mastery and an individual's aggressive attitude toward challenging situations.

Activities of Daily Living↗

PubMed1997

Cytogenetic abnormalities and clonal evolution in an adult hepatoblastoma.

Hepatoblastomas usually occur in children < 3 years of age, and only occasional adult cases have been described. To date, 20 cytogenetically abnormal childhood hepatoblastomas have been reported. Karyotypic investigations have shown that most hepatoblastomas are diploid or hyperdiploid, often displaying trisomies for chromosomes 2 and 20. We have cytogenetically investigated an adult hepatoblastoma for which no previous karyotypic data exist. A hypertriploid stemline with multiple numerical and structural chromosomal aberrations, including +2 and +20, was found. In addition, the tumor displayed extensive clonal evolution with 11 subclones. Although the tumor thus displayed some chromosomal abnormalities commonly observed in childhood tumors, providing further support for the importance of these abnormalities in the development of hepatoblastoma, the level of genomic complexity seen in the present case has never been described in childhood hepatoblastomas and may suggest a different etiology or pathogenesis.

Aged↗

PubMed1997

Characterization of five conserved genotypes of the mumps virus small hydrophobic (SH) protein gene.

Twenty-one different mumps virus isolates from Sweden and Japan collected over 25 years were compared by nucleotide sequence analysis of the small hydrophobic (SH) protein gene, and the deduced 57 amino acid sequences of the coding part of the gene were aligned with published sequences of viral isolates from the USA, the UK, Sweden and Japan. Five genotypes were found which, in accordance with previously used nomenclature, were named A to E. Genotypes A, C, D and E were found in Europe and genotype B was found in Japan. Amino acid signature sequence motifs specific for each genotype were identified. A triplet of three amino acids at positions 28-30 was the most characteristic. Different genotypes can circulate simultaneously in a given geographical location. In Stockholm, genotypes A and D or C and D were found over different time periods. In contrast, only genotype B was found in Japan.

Amino Acid Sequence↗

PubMed1997

Characterization of genotype-specific epitopes of the HN protein of mumps virus.

The SBL-1 strain of mumps virus, grouping with genotype A on the basis of the small hydrophobic protein gene sequence, was grown in the presence of three different monoclonal antibodies. The monoclonal antibodies were directed against the haemagglutinin-neuraminidase (HN) protein and they inhibited haemagglutinating activity and infectivity of the virus. The HN genes of the nine neutralization-escape virus mutants were sequenced and the predicted amino acid sequences were compared with that of the parental virus. Amino acid substitutions were found at positions 269, 352 and 354, respectively, of the 582 amino acid long protein. The three monoclonal antibodies did not react with 35 virus strains isolated in Stockholm during the years 1970 to 1985. Thirteen and four of the strains were found to belong to the D and C genotypes, respectively. A type-specific neutralization antibody response was also found in sera of rabbits hyperimmunized with purified virions of genotype A and D. The genotype-specific difference in neutralizing activity in mice and rabbits was not corroborated by an overall difference in the amino acid sequence of the HN protein of the different genotypes. Further studies are needed to explore the efficacy of mumps virus vaccines for protection against homologous and heterologous genotypes of mumps virus.

Amino Acid Sequence↗