Search PubMed⌕ Search

Biomedical subjects

M Berg

Publications and source records attributed to M Berg.

At least 19 recordsLinked to original sources
PubMed1992

Rheological and immunological findings in dockers with vibration-induced white fingers.

The aim of the present study was to characterize rheological and immunological features involved in the pathogenesis of vibration-induced white fingers (VWF). Plasma viscosity, at two shear rates (580 s-1 and 1164 s-1), levels of immunoglobulins (IgG, IgM, IgA), circulating immune complexes, rheumatoid factor, antinuclear antibodies, fibronectin, fibrinogen, hemoglobin and erythrocyte sedimentation rate were analysed in 30 male dockers with VWF and in 30 healthy male referents unexposed for hand-arm vibrations. Decreased plasma viscosity was observed among the men with VWF, although formal significance (P less than 0.05) was only obtained at shear rate 580 s-1. The decrease was mainly seen among smokers. In the study there were no significant differences between the VWF group and the referents with regard to immunoglobulin levels, autoantibodies and other plasma proteins. From the study it is concluded that workers with VWF may have a decreased plasma viscosity. The biological relevance of this observation is uncertain and deserves further study.

Adult↗
PubMed1992

The haemagglutinin-neuraminidase glycoprotein of the porcine paramyxovirus LPMV: comparison with other paramyxoviruses revealed the closest relationship to simian virus 5 and mumps virus.

The complete nucleotide sequence of the haemagglutinin-neuraminidase (HN) gene of the porcine paramyxovirus LPMV, was determined from cDNA derived from viral genomic RNA. The gene was 1906 nucleotides long including a putative gene end and poly A signal. One long open reading frame was found encoding a protein of 576 amino acids with a calculated molecular weight of 63,324. The protein contains four potential N-glycosylation sites and a major hydrophobic region near the N-terminal, suggesting a membrane anchor domain. Comparison of the deduced amino acid sequence of the LPMV HN protein with that of other paramyxovirus HN proteins, revealed the highest amino acid identity to simian virus 5 of 43% and mumps virus of 41%.

Amino Acid Sequence↗
PubMed1992

The molecular biology of the porcine paramyxovirus LPMV.

Protein and genomic studies of a previously uncharacterized porcine paramyxovirus (designated LPMV) confirmed that it was a member of the paramyxovirus genus. The nucleotide sequences and deduced amino acids of the complete P-gene, M-gene, F-gene and HN-gene as well as the intergenic sequences have been determined. Comparative sequence analysis of the M-gene of LPMV revealed the closest relationship of LPMV was to human mumps virus with a homology of 46% and 55% at the amino acid and nucleotide levels respectively. The P-gene of LPMV is transcribed to V protein mRNA and by editing of the gene to the P protein mRNA. The LPMV P-gene has the coding capacity for an additional protein of 126 amino acids, a C protein.

Amino Acid Sequence↗
PubMed1992

The P gene of the porcine paramyxovirus LPMV encodes three possible polypeptides P, V and C: the P protein mRNA is edited.

The nucleotide sequence of the P gene of the porcine paramyxovirus La-Piedad-Michoacan-Mexico virus (LPMV) was analysed. Three long open reading frames (ORFs) were found in the mRNA sense. Insertion of two G residues is necessary to obtain an ORF encoding the P protein, which gives a P protein of 404 amino acids with a calculated Mr of 42475. This form of editing was demonstrated, two non-templated G residues being added in a portion of the mRNA transcripts. The LPMV V protein, which has a conserved cysteine-rich C-terminal region, is encoded by an exact copy of the P gene. The third ORF has the capacity to encode a protein of 126 amino acids, which may resemble the C proteins found in some paramyxoviruses. The ORF starts from an AUG codon down-stream of the first AUG codon of the P/V ORF.

Amino Acid Sequence↗
PubMed1992

Reliability of an automatic sensing algorithm.

Automatic adaptation of the atrial sensitivity was evaluated in 18 patients with dual chamber pacemakers (Intermedics, Inc., Relay) in the unipolar mode. After atrial sensitivity was stabilized in the upright position, patients underwent a 1.0 W/kg body weight exercise for 5 minutes. A 24-hour Holter ECG was recorded, and the maximum and minimum atrial sensitivity values reached were stored in the memory of the pulse generator. In a second series of 12 patients, Holter ECGs were recorded twice, starting with the same sensitivity but with automatic adaptation alternately switched "on" or "off." Results of the exercise test: mean atrial sensitivity declined from 2.30 +/- 0.77 mV to 2.03 +/- 0.68 mV. There was no change in five patients, a slight increase in two patients, and lowering of the atrial sensitivity was observed in 11 patients, the difference ranging from 0.2 to 1.0 mV. A total of two P waves in two patients were missed by the atrial amplifier. The minimum and maximum sensitivity reached during Holter monitoring averaged 2.31 +/- 0.67 mV versus 1.72 +/- 0.71 mV (difference 0-1.7 mV). Normal pacemaker function was found in six patients, including one patient without any intrinsic atrial activity. Malsensing of less than five P waves occurred in four patients. More than 50 sensing defects resulted from ectopic atrial beats (four patients). We observed atrial oversensing in three cases; one patient showed atrial over- and undersensing. The comparison between fixed and variable sensitivity did not reveal any superiority of automatic adaptation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Limbic seizure-induced changes in extracellular amino acid levels in the hippocampal formation: a microdialysis study of freely moving rats.

Limbic seizure-activity was induced by injecting kainic acid into the amygdala of rats. Extracellular levels of amino acids were monitored by microdialysis in the hippocampus. No changes were detected in the levels of glutamate and aspartate. The level of glycine also remained unchanged, whereas GABA showed an increase of approximately 35%. The level of glutamine decreased by approximately 30%, and that of serine by approximately 20%. The results indicate that increased turnover may exist in the glutamate transmitter pool. In addition, impairment of GABA-release seems not to be a pathogenetic factor in seizure-induced hippocampal neuron loss. It is concluded that even during sustained seizure-activity, the extracellular level of glutamate, is maintained within narrow limits. A proposed index for excitatory neurodegeneration, glutamate x glycine/GABA, was found to be decreased in this seizure model. We therefore suggest that seizure-induced neuron death is not reflected by alterations in the extracellular levels of glutamate and aspartate, thought to act as direct neurotoxins.

Amino Acids↗
PubMed1992

Postoperative hearing recovery in a case of delayed hearing loss after acoustic neurinoma removal.

Delayed postoperative hearing loss after acoustic neurinoma removal is seldom observed. The presented case illustrates the phenomenon of delayed postoperative hearing loss which was observed 4 days after removal of a large acoustic neurinoma. Intraoperative brainstem auditory evoked potentials (BAEP) revealed a gradual loss of wave V with preservation of wave I. In animal experiments a dissociated loss of BAEP has been associated with impairment of microcirculation due to secondary edema. Vasoactive treatment was initiated and after 11 days a partial hearing recovery could be documented. Transient disturbance in microcirculation of vasa nervorum of the cochlear nerve is assumed to be responsible for postoperative hearing fluctuation.

Audiometry, Pure-Tone↗
PubMed1992

Techno-stress. A psychophysiological study of employees with VDU-associated skin complaints.

Little is known about the causes of health complaints associated with work with video display units (VDUs). The symptoms are to a large degree similar to those of "multiple chemical sensitivity." We observed 47 white-collar employees with and without VDU-associated skin complaints during a regular workday and a day of leisure. VDU workers with skin symptoms had higher levels of the stress-sensitive hormones thyroxin and prolactin compared with employees without symptoms. They also had lower levels of the anabolic hormone testosterone during work. VDU workers with skin complaints also reported more occupational mental strain. A model is proposed in which physiological signals act as unconditioned stimuli and the VDU environment as the conditioned stimuli.

Arousal↗
PubMed1992

Learning disabilities in children with borderline personality disorder.

Children with borderline personality disorder are known to have a variety of school problems, including low achievement. Clinicians working with these youngsters have estimated that one third or more may be learning disabled; however, no empirical studies have confirmed these estimates. The author reports the results of a study of 56 hospitalized borderline children in which score profiles from academic and cognitive measures were cluster analyzed. She examines the incidence of independent learning disabilities as well as subgroup membership, and discusses implications for treatment.

Achievement↗
PubMed1991

Kainic acid neurotoxicity: in vivo test of two new non-N-methyl-D-aspartate receptor antagonists.

The possible neuroprotective effects of two new non-N-methyl-D-aspartate receptor antagonists were determined by quantitative light microscopy after intracerebral administration of kainic acid (KA) in two rat brain regions. KA alone or KA in combination with the antagonists alpha-amino-3-carboxy-methoxy-5-methyl-4-isoxazolepropionic acid (AMOA) and alpha-amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)methyl-5-methyl-3 -oxo-4-isoxazoline-4-propionic acid (AMNH) were stereotaxically injected into the striatum or into the CA3 region of hippocampus. Seven days later neuropathological examination including cell counts was performed on paraffin sections from the two brain regions. In the striatum, AMOA almost completely attenuated KA-induced cell damage, whereas AMNH showed no protective effect. In the hippocampal CA3 region none of the test compounds possessed neuroprotective properties against KA. These results seem to be consistent with a difference in the mechanisms responsible for the neurotoxic action of KA in the hippocampus compared to the striatum.

Animals↗
PubMed1991

Multiple roles of Leu-8/MEL-14 in leukocyte adhesion and function.

Leu-8 and its murine homologue MEL-14 are members of a new family of adhesion molecules encoded on chromosome-1 that share common structural features, including lectin-like domains and tandem repeats homologous to complement binding proteins. The expression of Leu-8 is rapidly down-regulated during cell activation, both at the transcriptional level, and by a rapid post-translational event at the cell membrane, probably involving direct cleavage of the molecule from the cell surface. Lymphocytes that express Leu-8/MEL-14 bind selectively to HEVs in peripheral lymph nodes, and MEL-14 on neutrophils is thought to be important in the initial localization of neutrophils to sites of inflammation. In addition to its role in leukocyte adhesion, there is evidence that the Leu-8 molecule plays a role in cell function. Anti-Leu-8 monoclonal antibody increases suppressor activity of CD4+, Leu-8+ T cells for immunoglobulin synthesis, and anti-Leu-8 directly inhibits differentiation of Leu-8+ B cells. Together these findings indicate that the Leu-8 molecule in common with other cellular adhesion molecules is important not only in cellular adhesion, but also in modification of cell function.

Animals↗
PubMed1991

Lamina propria lymphocytes are derived from circulating cells that lack the Leu-8 lymph node homing receptor.

The Leu-8 membrane glycoprotein is the primate homologue of the murine MEL-14 peripheral lymph node homing receptor and is expressed on a majority of circulating lymphocytes but on few lymphocytes in the intestinal lamina propria. To examine the mechanisms regulating expression of the Leu-8-molecule on lymphocytes in different tissue sites, studies of Leu-8 membrane antigen expression, Leu-8 messenger RNA, and the Leu-8 gene were performed using normal human and nonhuman primate lymphocytes. Activation of resting peripheral blood lymphocytes caused a rapid decrease in membrane Leu-8 expression, a more gradual decrease in Leu-8 messenger RNA, and an increase in expression of interleukin 2 and interleukin 2 receptor messenger RNA. However, the down regulation of Leu-8 expression during activation was reversible because both membrane Leu-8 antigen and Leu-8 messenger RNA were reexpressed after 5 days of culture. Leu-8 messenger RNA was present in lymphocytes isolated from peripheral blood, spleen, and, particularly, mesenteric lymph node, but intestinal lamina propria lymphocytes contained very low levels of Leu-8 messenger RNA. The absence of Leu-8 messenger RNA in intestinal lymphocytes and circulating Leu-8 negative lymphocytes was not caused by recent activation in vivo because these cells did not have detectable interleukin 2 messenger RNA, and intestinal lymphocytes did not express Leu-8 after culture in vitro. Phorbol myristate acetate was found to be a strong inducer of Leu-8 messenger RNA in Leu-8-positive lymphocytes; however, phorbol myristate acetate did not induce membrane Leu-8 expression or Leu-8 messenger RNA in lamina propria lymphocytes. Leu-8-negative lymphocytes in peripheral blood or lamina propria did not have evidence of deletion or rearrangement of the Leu-8 gene. Leu-8-positive Jurkat cells and peripheral blood lymphocytes and Leu-8-negative peripheral blood and intestinal lymphocytes had partial methylation of an Msp I site in proximity to the Leu-8 gene, suggesting that in Leu-8-negative lymphocytes, the Leu-8 gene previously was transcriptionally active. In summary, these studies demonstrate that intestinal lamina propria lymphocytes have the same characteristics as circulating Leu-8-negative lymphocytes with respect to their state of activation and inability to express the Leu-8 antigen. The results suggest that the majority of lymphocytes that migrate to the intestinal lamina propria are derived from the subpopulation of circulating Leu-8-negative lymphocytes.

Animals↗
PubMed1991

Delayed hearing loss after surgery for acoustic neurinomas: clinical and electrophysiological observations.

In a series of 26 patients with medium-sized and large acoustic neurinomas and documented hearing before surgery, 7 patients had preservation of hearing initially after the procedure but then developed delayed hearing loss. The most prominent intraoperative electrophysiological finding in these cases was a gradual deterioration of brain stem auditory evoked potentials (BAEP), especially of Wave V. Four additional patients with a similar gradual intraoperative loss of BAEP and severe postoperative hearing deterioration received vasoactive treatment after surgery (low-molecular weight dextran). In all 4 patients, including 1 patient with documented total deafness after surgery, hearing was preserved. Initial preservation of cochlear nerve function after the removal of an acoustic neurinoma does not guarantee postoperative hearing. Intraoperative BAEP help to identify patients at risk for delayed postoperative hearing loss. The pathophysiological mechanism can be attributed to disturbances of the microcirculation in endoneurial vasa nervorum caused by the mechanical manipulation of the cochlear nerve.

Adult↗
PubMed1991

Identification of the porcine paramyxovirus LPMV matrix protein gene: comparative sequence analysis with other paramyxoviruses.

The complete nucleotide sequence of the gene encoding the matrix protein (M) of the porcine paramyxovirus LPMV has been determined. The gene is 1376 nucleotides long including 5' and 3' non-coding sequences with a protein-coding sequence of 1107 nucleotides. The deduced protein, containing 369 amino acids with a calculated Mr of 41,657, is hydrophobic overall with a net positive charge of +17.5. Comparative sequence analysis revealed high amino acid homology to other paramyxovirus M proteins, with the highest degree of identity (46%) with the human mumps virus. This is strong evidence that the porcine paramyxovirus LPMV is a genuine member of the paramyxovirus genus.

Amino Acid Sequence↗
PubMed1991

Loss of atrial signal detection with increasing sensitivity settings: a software problem and its practical solution.

A logic error in the software of Cosmos II results in apparent malsensing of atrial signals at high rather than low sensitivity settings. The paradoxical function was found in 54 out of 87 units tested (= 62%) if the atrial sensitivity was increased and in 54 out of 87 units tested (= 62%) if the atrial sensitivity was increased and the ventricular refractory period was lengthened beyond critical limits that could be defined individually. The problem inherent in both unipolar (66%) and bipolar systems (54%) is attributed to a summation of a physiological signal and internal noise, which has to be detected at the atrial level within a specific timing window to disable atrial sensing for the next pacing cycle. The malfunction virtually disappears if the ventricular refractory period does not exceed 210 msec. It is recommended, therefore, that Cosmos II pacemakers be left at their nominal ventricular refractory value (200 msec).

Adult↗
PubMed1991

Ultraviolet radiation compared to an ultra-clean air enclosure. Comparison of air bacteria counts in operating rooms.

Clean air in the operating room is important during joint replacement surgery. We compared monochromatic ultraviolet radiation of 254 nm with the use of a Charnley-Howorth air enclosure by bacterial air-sampling during 113 total hip arthroplasties. Air samples were taken continuously at the edge of the wound and every 15 minutes at a site 130 cm from the operating table. We also tested the effect of occlusive clothing for all personnel. Ultraviolet light was more efficient than the ultra-clean air enclosure, and occlusive clothing on its own or in combination also produced improvement. The implications of these findings are discussed.

Air Microbiology↗
PubMed1991

Topographical anatomy of the internal auditory canal. Implications for functional surgery in the cerebello-pontine angle.

For exposure of the cerebello-pontine angle by an enlarged middle-fossa approach without destruction of the inner ear, bone removal anterior and posterior to the internal auditory meatus (c.a.i.) can be performed with orientation at landmarks. Based on the experience of more than 300 interventions and documented by a series of 10 temporal bone micro-dissections, rules have been established for reliable localization of the following structures: geniculate ganglion, Fallopian canal, vertical crest at the fundus of the c.a.i., basal coil of the cochlea, and ampulla of the superior semicircular canal. The surgical technique has enabled the authors to remove acoustic neurinomas of up to 3.5 cm with preservation of hearing in 51%.

Cerebellar Neoplasms↗