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Biomedical subjects

L Jonsson

Publications and source records attributed to L Jonsson.

At least 37 records · Page 2Linked to original sources
PubMed1991

Regulation of sterol biosynthesis in sunflower by 24(R,S),25-epiminolanosterol, a novel C-24 methyl transferase inhibitor.

Whereas sitosterol and 24(28)-methylene cycloartanol were competitive inhibitors (with Ki = 26 microM and 14 microM, respectively), 24(R,S)-25-epiminolanosterol was found to be a potent non-competitive inhibitor (Ki = 3.0 nM) of the S-adenosyl-L-methionine-C-24 methyl transferase from sunflower embryos. Because the ground state analog, 24(R,S)-oxidolanosterol, failed to inhibit the catalysis and 25-azalanosterol inhibited the catalysis with a Ki of 30 nM we conclude that the aziridine functions in a manner similar to the azasteriod (Rahier, A., et al., J. Biol. Chem. (1984) 259, 15215) as a transition state analog mimicking the carbonium intermediate found in the normal transmethylation reaction. Additionally, we observed that the aziridine inhibited cycloartenol metabolism (the preferred substrate for transmethylation) in cultured sunflower cells and cell growth.

Cell Division↗
PubMed1991

Thermal degradation of carotenes and influence on their physiological functions.

Raw carrot juice contains a considerable amount of alpha- and beta-carotene, which makes carrot an excellent source of vitamin A. Heat treatment of the juice at temperatures comparable to those at pasteurization and boiling does not change the carotenes, while heating at temperatures used during sterilization results in rearrangement of the carotene molecules and a decrease in total carotenes. The all-trans alpha- and beta-carotenes appear partly as cis-isomers, especially the 13-cis-isomer. Isomerization of the carotenes leads to a decrease in their vitamin A activity. Carotenes also seem to be anticarcinogens but the extent to which this property is influenced by isomerization is still unknown.

Beverages↗
PubMed1991

Acute peripheral facial palsy simulating Bell's palsy in a case of probable multiple sclerosis with a clinically correlated transient pontine lesion on magnetic resonance imaging.

A transient pontine lesion was demonstrated in a young adult male who had a complete acute peripheral facial nerve palsy due probably to multiple sclerosis. In the acute stage of the palsy. T2-weighted magnetic resonance imaging (MRI) revealed a high signal intensity in the ipsilateral pons in the region of the nucleus and pontine part of the facial nerve. The patient recovered completely 5 weeks after the onset of the palsy, and at this stage, the lesion in the brainstem was no longer demonstrable on MRI. The onset and course of the disease resembled the idiopathic form of facial palsy (Bell's palsy): the present findings along with recent MRI and topodiagnostic studies may indicate that in some cases of Bell's palsy the primary lesion is located centrally. By improved MRI techniques and intravenous contrast agents it may be possible to visualize and follow the disease process and ascertain more of the pathogenesis of Bell's palsy.

Acute Disease↗
PubMed1991

Life events and coping patterns reported in HIV-infected hemophiliacs a year after diagnosis.

A nationwide study of the psychosocial situation of HIV-infected hemophiliacs was made in Sweden. Forty-three HIV-infected hemophiliacs aged between 12 and 72 years were compared with 30 age matched non-infected hemophiliacs. A group of 17 parents of HIV-infected boys was also studied. An unexpectedly high number of residential moves was found in the infected group during the period of diagnosis. The HIV infection diagnosis was rated the most disastrous event compared to all other studied events (including death of family member), particularly among parents of HIV-infected boys. With regard to coping, subjects were asked to record their "content of life" for the past, the present and the future. The most striking findings were the pessimistic ratings of expected number of activities with other people in the future. Such activities were assumed to decrease significantly in the infected, but not in the non-infected group. Furthermore, the ratings of possibility to influence activities were lower in the infected group compared to the non-infected. The content of activities, on the other hand, differed very little between the two groups, although non-infected men reported more hobbies and leisure activities and social activities than infected men.

Adaptation, Psychological↗
PubMed1990

Regulation of triacylglycerol biosynthesis in embryos and microsomal preparations from the developing seeds of Cuphea lanceolata.

Embryos of Cuphea lanceolata have more than 80 mol% of decanoic acid ('capric acid') in their triacylglycerols, while this fatty acid is virtually absent in phosphatidylcholine (PtdCho). Seed development was complete 25-27 days after pollination, with rapid triacylglycerol deposition occurring between 9 and 24 days. PtdCho amounts increased until day 15 after pollination. Analysis of embryo lipids showed that the diacylglycerol (DAG) pool consisted of mainly long-chain molecular species, with a very small amount of mixed medium-chain/long-chain glycerols. Almost 100% of the fatty acid at position sn-2 in triacylglycerols (TAG) was decanoic acid. When equimolar mixtures of [14C]decanoic and [14C]oleic acid were fed to whole detached embryos, over half of the radioactivity in the DAG resided in [14C]oleate, whereas [14C]decanoic acid accounted for 93% of the label in the TAG. Microsomal preparations from developing embryos at the mid-stage of TAG accumulation catalysed the acylation of [14C]glycerol 3-phosphate with either decanoyl-CoA or oleoyl-CoA, resulting in the formation of phosphatidic acid (PtdOH), DAG and TAG. Very little [14C]glycerol entered PtdCho. In combined incubations, with an equimolar supply of [14C]oleoyl-CoA and [14C]decanoyl-CoA in the presence of glycerol 3-phosphate, the synthesized PtdCho species consisted to 95% of didecanoic and dioleic species. The didecanoyl-glycerols were very selectively utilized over the dioleoylglycerols in the production of TAG. Substantial amounts of [14C]oleate, but not [14C]decanoate, entered PtdCho. The microsomal preparations of developing embryos were used to assess the acyl specificities of the acyl-CoA:sn-glycerol-3-phosphate acyltransferase (GPAT, EC 2.3.1.15) and the acyl-CoA:sn-1-acyl-glycerol-3-phosphate acyltransferase (LPAAT, EC 2.3.1.51) in Cuphea lanceolata embryos. The efficiency of acyl-CoA utilization by the GPAT was in the order decanoyl = dodecanoyl greater than linoleoyl greater than myristoyl = oleoyl greater than palmitoyl. Decanoyl-CoA was the only acyl donor to be utilized to any extent by the LPAAT when sn-decanoylglycerol 3-phosphate was the acyl acceptor. sn-1-Acylglycerol 3-phosphates with acyl groups shorter than 16 carbon atoms did not serve as acyl acceptors for long-chain (greater than or equal to 16 carbon atoms) acyl-CoA species. On the basis of the results obtained, we propose a schematic model for triacylglycerol assembly and PtdCho synthesis in a tissue specialized in the synthesis of high amounts of medium-chain fatty acids.

Acyl Coenzyme A↗
PubMed1990

Brain perfusion with intracarotid injection of 99mTc-HM-PAO in partial epilepsy during amobarbital testing.

Technetium (99mTc) hexamethyl propylene amine oxime (HM-PAO) was injected into the internal carotid artery in ten epileptic patients after the end of amobarbital speech-memory tests. The cerebral perfusion as visualized from SPET was compared to cerebral angiographies, which showed unilateral filling of intracranial vessels in seven patients. SPET revealed cross-flow between the hemispheres in four of these seven patients. In three patients in whom the angiograms had shown bilateral contrast filling, SPET showed cross-flow in only two. It is concluded that 99mTc-HM-PAO SPET examinations provide valuable information for correct interpretation of amobarbital tests on cognitive hemisphere functions. The SPET technique may help to explain atypical speech and memory responses caused by unusual intracranial vascularization.

Adult↗
PubMed1990

Bell's palsy: an immune complex disease.

Serum levels of C4-containing circulating immune complexes in 48 patients with Bell's palsy were studied by an enzyme-linked immunosorbent assay (ELISA) using chicken antibodies. We have previously reported elevated levels of C1q- and C3-containing immune complexes when compared to the serum of 42 healthy persons. We now found the levels of C4-containing immune complexes in these sera to be slightly decreased, but these patients' sera had a slightly increased ability to activate and bind C4 to a model immune complex. The results indicate that the fairly low levels of C4-containing immune complexes were not due to a defect in C4 activation but point to a rapid modification of C4 in the immune complex in vivo or low binding of C4 to the immune complexes. This study also shows that it is preferable to use assays that detect C1q- and C3-containing immune complexes when analyzing sera from patients with Bell's palsy.

Adult↗
PubMed1990

Magnetic resonance in Bell's palsy.

The brain and the brain stem were investigated by magnetic resonance (MR) in 19 patients with complete acute peripheral facial palsy, diagnosed as Bell's palsy. Five patients with a median age of 57 years had changes on T2 weighted MR: One patient showed transient signal changes with increased signal intensity in the ipsilateral brain stem. Another patient had persisting abnormal signals both in the brain and the brain stem. Two patients presented regions of high signal intensity in the subcortical cerebral white matter and still another patient had increased signal intensity in the periventricular white matter. MR abnormalities anatomically related to the facial nerve or its nucleus were not demonstrated. The significance of the MR findings is not quite certain but the MR pattern in conjunction with the patient's high median age most likely indicate vascular disease.

Adult↗
PubMed1989

Elevated serum interferon levels in patients with Bell's palsy.

Serum interferon (IFN) levels were analyzed in patients with Bell's palsy to study the immune response in the disease. Serum samples from 91 patients were assayed for antiviral activity using a bioassay. The IFN levels in the serum were elevated in the acute and convalescent phases as compared with control subjects. The serum IFN-gamma levels were analyzed by radioimmunoassay in 32 of the patients: the IFN-gamma levels were alike in the acute and convalescent phases and the control subjects. Neutralization with specific antisera against IFN-alpha, -beta, and -gamma on 15 serum samples of 11 patients with elevated IFN activity showed a complex pattern that indicates that the antiviral activity was due to a mixture of IFNs and possibly also due to other factors. The elevated IFN levels indicate a low-grade antiviral response that may reflect the reactivation of a viral infection.

Adult↗
PubMed1989

Magnetic resonance imaging in patients with Bell's palsy.

Magnetic resonance imaging of the brain and the brain stem was performed in 18 patients with complete acute peripheral facial palsy and diagnosed as Bell's palsy. In five patients T2 weighted images revealed regions of high signal intensity in the cerebral white matter and/or in the brain stem. The changes indicate that in cases of Bell's palsy the central nervous system may be involved and the disease may be related to microvascular or demyelinating disorder.

Adolescent↗
PubMed1988

Determination of circulating immune complexes by chicken anti-human C3 and anti-human C1q microELISA.

The present study reports on an anti-human C1q and an anti-human C3 microELISA for measuring circulating immune complexes (CIC). Affinity-purified chicken anti-human C3 and anti-human C1q were used as capture antibodies and protein A-alkaline phosphatase conjugate for detection. Chicken antibodies do not activate mammalian complement, do not react with rheumatoid factor and are not bound to anti-mammalian IgG antibodies or protein A, which often are used for detection in ELISA. They are therefore suitable as capture antibodies in CIC assays. We have tested Bell's palsy patients and found an increase in both anti-C3- and anti-C1q-containing CIC in acute and convalescent sera compared with the normal.

Animals↗
PubMed1987

Tick-borne Borrelia infection in patients with Bell's palsy.

An enzyme-linked immunosorbent assay was applied to serum samples of 94 patients diagnosed as having Bell's palsy: they were studied throughout two consecutive years in an attempt to establish serologic evidence of a tick-borne spirochetal infection. A strain of Borrelia spirochetes, isolated from Swedish Ixodes ricinus ticks, was used as an antigen, and separate estimations of spirochetal IgG and IgM antibodies were made; serum samples with titers above the 95th-percentile level of 120 healthy individuals were considered positive. Thirteen percent of the patients' serum samples were IgG-positive, 3% were positive for IgM, and 3% were positive for both IgG and IgM. A twofold or greater increase of IgG titers was found in 6%. All the patients who were seropositive experienced the onset of palsy during the period from July to December.

Adult↗
PubMed1987

Immune complexes and complement components in Bell's palsy.

The serum levels of circulating immune complexes were studied in 63 patients and the complement system in 36 patients with Bell's palsy. The IgG-C1q and IgG-C3 containing immune complexes were analyzed by an enzyme-linked immunosorbent assay. The levels were found to be significantly elevated in the acute and convalescent stages of the palsy compared with controls. The total complement activity as determined by a CH50 assay and complement component C3 titrations also showed elevated values. The levels of C2 were not altered. The results indicate in Bell's palsy an inflammatory process and an antigen-antibody response which may be triggered by a viral antigen.

Adolescent↗
PubMed1986

Electrophysiological properties of calcitonin-secreting cells derived from human medullary thyroid carcinoma.

Primary cultures of human medullary thyroid carcinoma tissue were prepared from lymph node metastases in two patients. The parenchymal, cultured cells displayed positive immunocytochemical staining for CT, and the cells also released the hormone into the culture medium. The membrane potential and resistance of the CT-producing cells were 50.1 +/- 8.9 mV and 634 +/- 154 M omega (mean +/- SD, n = 46). TTX sensitive action potentials with maximum rate of rise up to 51 V s-1 were evoked by current injection in Na+-containing solution, whereas TTX insensitive action potentials with maximum rate of rise up to 9 V s-1 were generated in Na+-free solution. These action potentials were reversibly blocked by D-600. We conclude that the action potentials of the human MTC cells have both a Na+ and a Ca2+ component. Ejection of CA2+-free solution close to the cells caused membrane hyperpolarization associated with decreased membrane resistance. The reversal potential of this response was -66.2 +/- 10.9 mV (n = 10), indicating that a permeability increase to Cl- and/or K+ may be involved. We suggest that elevated plasma Ca2+ concentration in vivo may cause increased excitability due to membrane depolarization and resistance increase, thus leading to enhanced Ca2+ influx and hormone secretion.

Action Potentials↗
PubMed1985

Effects of various brans on energy intake and glucose metabolism in alloxan diabetic rats.

The purpose of the present study was, firstly, to determine whether untreated rye bran and untreated wheat bran differ in their ability to affect energy intake and glucose metabolism in alloxan diabetic rats; and secondly, to find out whether wheat brans processed by extrusion-cooking or acid-treatment differ in this respect. A low-fiber high-starch diet was used as reference. There was a positive correlation between energy intake and urinary glucose excretion. No correlation between these parameters and weight increase was found. The mean urinary glucose excretion was lowest in the animals fed untreated rye bran (68 +/- 3 mmoles/24 h). No difference in urinary glucose excretion was found in the three different wheat bran groups (range of means: 102 +/- 10 - 105 +/- 7 mmoles/24 h). The highest urinary glucose excretion was found in the group fed the low-fiber high-starch diet (160 +/- 12 mmoles/24 h). It is thus concluded that untreated rye bran lowered urine glucose more than did untreated wheat bran, and that extrusion-cooking or acid-treatment did not change the urine glucose lowering effect of wheat bran.

Animals↗
PubMed1984

Behavioral determination of olfactory thresholds to amyl acetate in dogs.

By use of a modified conditioned suppression technique, olfactory thresholds to amyl acetate were determined for four beagle dogs. Using the same odorant and olfactometer and a similar breathing chamber, olfactory thresholds were obtained in eight human subjects. It was determined that the olfactory sensitivity of the dogs was about 2.5 log units better than that of the human subjects.

Animals↗
PubMed1984

Twenty-four-hour free-feeding patterns of dogs eating dry food.

In order to provide some detailed information on the feeding behavior of freely-feeding dogs, four adult beagles were maintained in an isolated outdoor environment where food and water were freely available. Observations across an 8-month period indicated that the dogs are episodically (in "meals") and that the total daily intake of food and water changed as the observation period progressed, most likely as a consequence of change in the ambient environmental conditions across seasons. Within-day changes in ambient temperature, and the timing of daily maintenance activities in the animal's runs influenced the temporal distribution of meals with the day.

Animals↗