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Biomedical subjects

J Huttunen

Publications and source records attributed to J Huttunen.

At least 73 records · Page 4Linked to original sources
PubMed1991

DNA polymorphisms of apolipoprotein B and AI/CIII genes and response to gemfibrozil treatment.

Apolipoprotein B XbaI polymorphism and apolipoprotein AI/CIII SstI polymorphism have been found to be associated with variations in serum lipoprotein levels. We investigated whether these gene polymorphisms are involved in determining the lipid-modulating action of gemfibrozil. Of the 221 male subjects with hyperlipidemia studied, 121 responded well to the treatment with more than a 25% reduction in the non-high-density lipoprotein cholesterol level, whereas 100 were nonresponders. Among responders, but not nonresponders, homozygosity for the apolipoprotein B X2 allele (XbaI site present) and heterozygosity for the apolipoprotein AI/CIII S2 allele (SstI site present) were associated with elevated baseline serum low-density lipoprotein cholesterol and triglyceride levels, respectively. However, the hypolipidemic effect of gemfibrozil among the responders was independent of these gene polymorphisms. These data indicate that common polymorphisms of the apolipoprotein B and apolipoprotein AI/CIII gene loci influence serum lipid levels by mechanisms that are amenable to an intervention with gemfibrozil.

Adult↗
PubMed1990

EMG responses in leg muscles to postural perturbations in Huntington's disease.

This paper compares leg muscle electromyogram (EMG) responses to sudden toe-up tilts of a moveable platform in patients with Huntington's disease (HD), clinically normal offspring at risk of developing HD (HD risks) and healthy controls. The EMG pattern in standing subjects and patients consisted of short- and middle-latency responses (SL and ML) in the stretched triceps surae muscles and long-latency responses (LL) in the shortened tibialis anterior muscles. The SL response could be further divided into two distinct subcomponents termed SL1 and SL2. An ML response was identified in only 50% of normal subjects and patients. HD patients differed from normal subjects by showing delayed onset latencies and prolonged durations for the LL response, and smaller amplitudes for the ML response. The subjects at risk also showed diminished ML amplitudes and prolonged LL durations, but normal LL onset latencies. In the sitting condition, the EMG responses of the HD patients and of the HD risks did not differ from those of controls: in all groups SL1 was reduced and delayed, SL2 slightly enhanced, while ML and LL were absent. Because both afferent and efferent conduction times are normal in HD, the delayed LL onset reflects abnormal supraspinal organisation of postural control in HD, and indicates that basal ganglia may have a modulatory effect on the LL responses. The normal EMG responses in the sitting patients suggest appropriate regulation of these responses according to postural set in HD.

Adult↗
PubMed1989

Effect of submaximal exercise at low temperatures on pulmonary function in healthy young men.

In order to understand more fully the effect on pulmonary function of whole body exposure to cold during submaximal exercise, we measured pulmonary function indices in ten healthy male students and ten healthy male forestry workers of similar age following submaximal treadmill walking at different temperatures in a climatic chamber. After measuring the maximal aerobic capacity with a cycle ergometer test, the subjects had to walk on four separate occasions in the climatic chamber at an intensity of 70%-75% of their individual maximal heart rate; the first at normal room temperature and then randomly, either at 0 degrees C or at -20 degrees C, and vice versa. The duration of each walk was 8 min. Finally, each subject had to walk in the chamber at -20 degrees C for 17 min. Flow volume spirometry was performed at room temperature 1, 5, 10, and 20 min after exercise and the values were compared to baseline values taken prior to the last walking test. There were only minor changes in pulmonary function indices following exercise at different temperatures. Only one student showed a reduction of over 15% in peak expiratory flow rate after an 8-min walk at -20 degrees C. It seems that submaximal exercise of short duration, even at a temperature as low as -20 degrees C, does not impair pulmonary function in healthy young men.

Adult↗
PubMed1988

Neuromagnetic responses from a deaf subject to stimuli presented through a multichannel cochlear prosthesis.

Neuromagnetic responses to stimuli presented through a 4-channel cochlear prosthesis were recorded from a deaf subject. The topography of the responses agreed with activation of the supratemporal auditory cortex. The responses to tone pips, noise/square-wave sequences, and to intermittent frequency modulation of a continuous tone resembled those obtained from subjects with normal hearing, being consistent with the good performance of this subject with his implant.

Acoustic Stimulation↗
PubMed1987

Cortical origin of middle-latency auditory evoked responses in man.

We have recorded middle-latency magnetic evoked responses to 50-ms noise bursts, presented once every 0.9 s, over the right hemisphere of healthy humans. The measurements were carried out with a sensitive 7-channel SQUID gradiometer with a passband of 0.5-2000 Hz. The response consisted of peaks at about 30, 50 and 65 ms. The location of the equivalent source of the 30-ms deflection agrees with activation of the supratemporal auditory cortex, slightly anterior to the source area of the well-known 100-ms deflection.

Acoustic Stimulation↗
PubMed1987

Long-latency OFF-responses from the human sensorimotor cortex to tetanizing stimulation of thenar muscles.

Neuromagnetic recordings revealed a new type of OFF-response from the human sensorimotor cortex 170-235 ms after the end of tetanization of the thenar muscles with 10-240 Hz electrical pulse trains, delivered directly to the thenar eminence or to the median nerve at the wrist. No OFF-responses were discerned when the skin of the thumb was stimulated. The role of muscle afferents in the generation of the OFF-response is discussed.

Adult↗
PubMed1987

Cerebral magnetic responses to stimulation of ulnar and median nerves.

We have compared spatial patterns of somatosensory evoked magnetic fields (SEFs) to stimulation of the ulnar and median nerves at the wrist. An oddball paradigm was used additionally to examine whether an infrequent change in the stimulation site would alter the field pattern. The response consisted of 3 parts: an early small deflection at 22-28 msec, a large deflection peaking between 34 and 86 msec, and a late deflection at 110-180 msec. The wave forms and amplitudes of the responses to ulnar and median nerve stimulation were similar, without any additional deflections for the infrequent stimuli. The field patterns, which were interpreted in terms of the dipole model, could be explained by activation of the primary sensorimotor cortex during all peaks of the response. For the early parts of the response at 22-46 msec, the locations of the equivalent sources for median and ulnar nerve stimulation differed from each other, in agreement with the known somatotopy of SI. No somatotopical order was found for the sources of the later deflections.

Adult↗
PubMed1987

Cerebral magnetic responses to stimulation of tibial and sural nerves.

We report somatosensory evoked magnetic fields (SEFs) to stimulation of the mixed posterior tibial nerve (PTN) and the sensory sural nerve (SN) in 6 healthy subjects. The first peak of the responses occurred at 39-50 ms (P40m), with a 2-3 ms longer latency for SN than PTN stimulation. Within 200 ms several other deflections followed, with interindividually varying waveforms and latencies. Magnetic field mappings indicated that the source of P40m for PTN can be modelled by a single equivalent current dipole at the primary sensorimotor cortex; for the smaller responses to SN stimulation the single dipole model was less applicable. Field patterns for later deflections differed from those of P40m, indicating that several current sources within or near the primary foot projection area are sequentially activated after stimulation of both a mixed and a sensory lower limb nerve. These late deflections could not always be satisfactorily explained by single current dipoles, suggesting more complex geometries for the underlying neural activity.

Adult↗
PubMed1987

Crossmodal interaction is reflected in vertex potentials but not in evoked magnetic fields.

Magnetic responses and slow vertex potentials evoked by tone bursts and median nerve shocks were recorded in healthy humans to study crossmodal interaction. Stimuli were presented either alone, simultaneously or in pairs separated by 0.5 s; the interstimulus interval was 5 s. Simultaneous or preceding stimuli of another modality did not influence the amplitudes of the magnetic responses, which are known to be generated at modality specific projection areas. However, the electric vertex potentials decreased in amplitude in similar situations, suggesting that the electric and magnetic responses reflect neural events of at least partly different brain areas. Our results do not give support for crossmodal interaction at the sensorimotor or auditory cortices.

Acoustic Stimulation↗
PubMed1986

Magnetic cortical responses evoked by tactile stimulation of the middle finger in man.

Topographic distribution of cerebral magnetic responses to air-puff stimulation of the hairy skin of the middle finger was studied in healthy humans. The magnetic response was biphasic, with peak amplitudes at 57 +/- 16 ms and 108 +/- 34 ms. The field distributions for both deflections were interpreted in terms of equivalent current dipole sources at SI; the sources were different for the two deflections, although spatially close to each other. The electric evoked response was more complex in waveform, possibly reflecting activation of additional radial or deep current sources.

Adult↗
PubMed1986

Cortical responses to painful CO2 stimulation of nasal mucosa; a magnetoencephalographic study in man.

Magnetic and electrical responses to CO2 stimulation of the nasal mucosa were recorded in 4 subjects. The magnetic responses peaked at 350-400 msec, coinciding with the negative vertex potential. The field pattern suggested neural activation in the upper bank of the sylvian fissure near the lateral end of the central sulcus, i.e., at or near SII. The results also suggest that this area contributes to the generation of the electrical vertex potential.

Adult↗
PubMed1986

Selective adrenergic beta-2-receptor blocking drug, ICI-118.551, is effective in essential tremor.

Eighteen patients with essential tremor were treated for 2 days with a non-selective adrenergic beta-blocking drug (dl-propranolol, 80 mg X 3), a beta-2-selective blocker (ICI-118.551, 50 mg X 3) and placebo (X 3) in a randomized double blind cross-over study. Postural hand tremor was recorded with an accelerometer before administration of the drugs and at the end of each treatment period. Compared with placebo, both the beta-blocking drugs caused a statistically significant decrease in tremor intensity and they possessed approximately similar antitremor potency. Subjective benefit was reported by 12 of the 18 patients receiving ICI-118.551, 13 when on propranolol and 3 when on placebo.

Adrenergic beta-Antagonists↗
PubMed1986

Ineffective treatment of essential tremor with an alcohol, methylpentynol.

Six patients with essential tremor tested in the therapeutic effectiveness of a 6-carbon alcohol, methylpentynol, 200 mg/day, against placebo in a randomised double-blind clinical cross-over trial. The effect of methylpentynol on postural tremor amplitude was not different from that of placebo.

Adult↗
PubMed1986

Cerebral magnetic fields evoked by peroneal nerve stimulation.

We measured evoked magnetic fields and evoked potentials to peroneal nerve stimulation in healthy humans. The results were consistent with activation of the primary sensorimotor foot area on the mesial surface of the hemisphere during several deflections between 40 and 200 msec. A cortical origin is suggested for the electrical P40. Distinct magnetic field patterns were observed over the primary and secondary somatosensory cortices (SI and SII). At SII, responses to ipsilateral stimulation were weaker and had longer latencies than those to contralateral stimulation. Simulations were used to clarify the differences between electrical and magnetic patterns when SI and SII were simultaneously active.

Adult↗
PubMed1985

Initial treatment of parkinsonism with 8-alpha-amino-ergoline.

We treated 12 patients with Parkinson's disease with an 8-alpha-amino-ergoline derivative, CU 32-085. The daily dosage was increased slowly to 7 mg over 9 weeks, held constant for 8 weeks, then replaced by placebo for 4 weeks. We found statistically significant benefit over placebo or pretreatment disability. The effect was seen at daily dosages of 3 mg or more. Its magnitude was dose related. There was no further improvement on prolonged treatment with 7 mg daily. Side effects were mild and did not require interruption of treatment.

Adult↗