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Biomedical subjects

H Hefter

Publications and source records attributed to H Hefter.

At least 91 records · Page 5Linked to original sources
PubMed1990

Treatment of chronic relapsing inflammatory demyelinating polyneuropathy by cyclosporin A and plasma exchange. A case report.

A patient with chronic relapsing inflammatory demyelinating polyneuropathy was successfully treated with plasma exchanges and cyclosporin A (CsA). Dynamometric measurements of hand force during the time of CsA treatment showed a highly significant correlation between hand force and CsA blood levels. The largest influence of CsA on hand force occurred 11-13 days after CsA uptake.

Chronic Disease↗
PubMed1990

Motor dysfunction in HIV-infected patients without clinically detectable central-nervous deficit.

Motor tests were performed in 50 HIV-infected patients in all stages according to the current CDC classification, but without any clinically evident central nervous system deficit, and the results compared with an age-matched control group. Patients were excluded from the study if there was alcohol or drug abuse, fever and/or opportunistic cerebral infection. The parameters tested were postural tremor of the outstretched hands, most rapid voluntary alternating index finger movements (MRAM) and rise time of most rapid index finger extensions (MRC). Whereas tremor peak frequencies did not differ significantly in the patients and controls, MRAM and rise times of MRCs showed significant slowing in the patient group. Morphologically, the motor test performance of the HIV-infected patients was similar to that of patients with manifest basal ganglia disease (Parkinson's, Huntington's and Wilson's diseases). MRI scans of all patients were normal. It is concluded that in HIV-infected patients there is a very early subclinical central nervous system affection, especially of the basal ganglia, which is detectable with appropriate, quantitative motor function tests. These functional abnormalities precede the structural alterations in the MRI scans.

Adult↗
PubMed1990

Disturbances in human arm movement trajectory due to mild cerebellar dysfunction.

The temporal structure of arm movements was studied in nine cerebellar patients with mild impairment of the upper limbs and in six age-matched control subjects. The experimental paradigm consisted of visually guided, step tracking movements about the elbow. Movements ranged from 10 degrees to 70 degrees in amplitude and were made under different instructions (fast, fast/accurate, accurate). As in normal subjects, cerebellar patients were able to scale peak velocity with movement amplitude. This relationship was highly linear under all instruction conditions. Similar relationships existed between movement duration and amplitude. In contrast to normal subjects who produced movements with nearly symmetric velocity profiles, movements made by cerebellar patients were characterised by short acceleration and long deceleration durations. The degree of asymmetry was directly related to movement duration but was unaffected by movement peak velocity. Acceleration durations did not increase beyond 300 ms even in movements lasting up to 1s. These findings demonstrate that, despite little or no obvious impairment of the limb during routine examination, the temporal structure of voluntary movements in cerebellar patients is clearly disturbed. This supports the view that the production of an optimal movement trajectory is under cerebellar influence.

Adult↗
PubMed1989

Single-dose ciprofloxacin in the treatment of uncomplicated urinary tract infection in women.

In a randomised, double-blind trial two single-dose regimens of ciprofloxacin were evaluated for treatment of acute urinary tract infection (UTI) in women. Fifty-three women received 250 mg and 46 750 mg of ciprofloxacin. Seven days after treatment the eradication rate was 81.1% and 82.6% in the low and high dose groups respectively; the clinical cure rate at 28 days was 64.1% and 73.9% respectively. In women with recurrent UTI a significantly better response was found with the high dose regimen (92% versus 68%; p less than 0.001). It is concluded that a single 250 mg dose of ciprofloxacin is effective for treatment in most women with acute UTI, but in women with recurrent infection a 750 mg dose is preferable.

Adolescent↗
PubMed1989

[New electrophysiological findings on the incidence of brain involvement in clinically and neurologically asymptomatic HIV infections].

Motor (postural tremor of the outstretched hands, most rapid voluntary alternating index finger movements and rise times of most rapid voluntary isometric index finger extensions) and psychometric tests (multiple choice vocabulary test - form b, syndrome short test, the German version of the standard progressive matrices - Raven, and the psychic and somatic findings according to the AMDP-system) as well as MRI-Scans were analysed in 100 HIV-infected patients of all stages according to the actual CDC-classification, but without any central-nervous or psychic deficit. Patients with drug, alcohol or tranquilizer abuse, opportunistic, cerebral infections or fever were excluded from the study. Tremor-peak-frequencies and reaction times did not show any significant difference to an age- and sex-matched control group; the other motor parameters revealed significant slowing in the patient group and a worsening with the CDC-stages. MRI-scans of all the patients were normal. The psychometric tests did not show significant alterations on a group statistical level, especially not in the depression scales. Morphologically, the motor performances of the HIV-infected patients resembled those of patients with basal ganglia diseases (M. Huntington, M. Wilson, M. Parkinson). Correspondingly, in some cases of clinically demented HIV-positive patients, MRI-scans showed lesions in the basal ganglia. It can be concluded, that there is an early subclinical central-nervous system affection in HIV-infected patients, especially of the basal ganglia, detectable with appropriate motor function tests sometimes considerably preceeding structural deficits seen later in the course of the disease in MRI-scans.

AIDS-Related Complex↗
PubMed1988

Single low-dose ofloxacin for the treatment of uncomplicated urinary tract infection in young women.

Fifty premenopausal women with uncomplicated urinary tract infection (UTI) were treated with a single dose of 100 mg of ofloxacin. Duration of symptoms before the treatment, number of episodes of UTI during the last year, association with sexual activity, and the use of contraceptives were evaluated in relation to the clinical and microbiological response. Forty-seven women (94%) were cured clinically and microbiologically three days after treatment. Follow up at 28 days disclosed that 43 (86%) were free of symptoms and in 40 (80%) the urinary cultures were negative. Significantly higher rates of microbiological failure or reinfection were found among women with three or more episodes of UTI during the last year. This study shows that a single dose of ofloxacin is effective for therapy of uncomplicated UTI in young women.

Adolescent↗
PubMed1987

Stability of frequency during long-term recordings of hand tremor.

During recording of physiological postural hand tremor over a period of 60 min tremor peak frequency (PF) did not change in 14 normal subjects as long as the mechanical conditions were not changed. In contrast, tremor amplitude and synchronization of the corresponding EMG varied considerably. Any alteration in hand mechanics such as changing hand position or adding masses led to changes of PF according to the alteration in mechanical resonant properties. The results show that PF of physiological postural hand tremor is mainly determined by mechanical factors. There is no evidence for a systematic decrease of PF (Stiles et al. 1976) or for the emergence of a formerly described (Lippold 1981) 4-6 Hz tremor component with prolonged maintenance of posture. In the pathological tremor forms of Parkinson's disease or essential tremor PF also remained unchanged during prolonged maintenance of posture.

Adolescent↗
PubMed1987

Impairment of rapid movement in Huntington's disease.

Patients with Huntington's disease (HD) and relatives at risk were examined with respect to their capacity to produce rapid voluntary motor activity. For this purpose, the fastest possible self-paced single isometric forefinger extensions and the fastest alternating forefinger movements were tested. In addition to these fastest voluntary performances, the time course of spontaneous hyperkinetic finger movements and the peak frequency of finger and hand tremor were analysed as a measure of the temporal characteristics of involuntary movements. Comparison of these parameters in HD patients and individuals at risk with age and sex-matched normal controls revealed a significant slowing of all types of contractions or movements in the majority (up to 95%) of the patients and in up to 40% of the relatives at risk. Reaction times were only slightly prolonged, and the abnormalities of the movement parameters showed no correlation with detailed psychometric data. Hence it is unlikely that the disturbance in the execution of rapid motor acts is due to dementia. Tremor was also slower than normal and the hyperkinesias were still slower than the fastest voluntary contractions. It appears from this study that slowness of motor performance is not only evident in Parkinson's disease but may represent a more general dysfunction in basal ganglia disease.

Adult↗
PubMed1987

Natural history of asymptomatic extracranial arterial disease. Results of a long-term prospective study.

The natural history of asymptomatic extracranial arterial disease (EAD) was studied prospectively in 339 patients admitted for serial ultrasound Doppler examinations. Annual mortality was high at 7%, but stroke mortality was low at 0.6%: 82 patients (24%) died during the follow-up period, which lasted up to seven years (median: 29 months), only 10 from stroke but 41 from cardiac causes. The risk of suffering a stroke without premonitory transient ischaemic attacks (TIAs) was similarly low at 0.4%. Progression of EAD was the only predictor established to indicate the individual patient's cerebrovascular prognosis among a series of criteria tested (age, sex, degree and extent of carotid and/or vertebral disease, risk factors and indicators of atherosclerosis). Deterioration of EAD was observed in 108 (36%) of 296 patients by repeated Doppler examination, 174 (59%) remained constant and 14 (5%) showed an improvement. The observed low rate of strokes without premonitory TIAs is not in favour for early carotid endarterectomy in the majority of neurologically asymptomatic patients.

Adult↗
PubMed1987

Differential effects of changes in mechanical limb properties on physiological and pathological tremor.

The effect of changes in mechanical limb properties on the peak frequency of different tremor forms was analysed. Wrist tremor was recorded by an accelerometer fixed to the dorsum of the hand and demodulated surface EMG was recorded from the wrist extensors, while the extended hand was loaded with successively heavier weights. Physiological tremor was characterised by flat EMG spectra and a gradual decrease in tremor peak frequency with increasing load, as would be expected from the properties of a passive spring-mass-system. Also the peak frequency of activated physiological tremor characterised by increased synchronisation between motor units decreased in frequency with increasing loads. EMG spectra showed clear peaks of activity at the various mechanically determined tremor frequencies. In contrast, in two pathological tremor forms, the postural tremor in Parkinsonian patients and essential tremor, peak frequency tended to remain stable irrespective of changes in load. The method therefore allows a simple distinction between physiological and these two pathological tremors.

Adolescent↗
PubMed1986

The muscle activity spectrum: spectral analysis of muscle force as an estimator of overall motor unit activity.

Starting from the observation that the part above 6 Hz of the power spectrum of force tremor during isometric contractions can be related to the unfused twitches of motor units firing asynchronously, an attempt was made to study the usefulness of force tremor spectral analysis as a global descriptor of motoneurone pool activity. To compensate for the mechanical low-pass filter characteristic of skeletal muscle which leads to increased damping of mechanical ripples at higher frequencies, a numerical compensation rule was derived from data obtained by electrical microstimulation of small ensembles of motor units (MUs). Hidden line plots of consecutive partially overlapping spectra allowed visualization of changes in spectral composition during ongoing muscle activity. The resulting muscle activity spectra (MAS) showed broad peaks according to the range of onset firing rates in normal subjects. These tended to shift to higher frequencies with increasing force. Under conditions with increased synchronization of the MUs these broad peaks were replaced by sharp peaks corresponding to the burst repetition rate. Patients with different motor dysfunctions were selected to illustrate how alterations of MU activity are reflected in the MAS. Decreased or increased firing rates were observed as well as abnormal states of synchronization. It is concluded that the MAS provides useful information about some aspects of the discharge characteristics of ensembles of MUs and therefore represents a method to monitor some qualitative 'image' of the MU activities within a muscle.

Adolescent↗
PubMed1986

Event-related potentials in patients with Huntington's disease and relatives at risk in relation to detailed psychometry.

Event-related potentials (ERPs) were studied in patients with Huntington's disease (HD) and their offspring at risk in a simple auditory oddball paradigm requiring the counting of the rarer of two stimulus categories. Group statistical analysis revealed prolongation of latencies of components P2, N2 and especially P3 in HD patients and to a lesser extent in at-risks. In a large population of normals the age-latency relationship for component P3 showed a non-linear shape with increasing slope and scatter in the older age groups. A bipartate linear regression analysis splitting the normal population at age 50 was used for detection of abnormalities of P3 latency in individual cases. Abnormal P3 latencies were present in the majority of HD patients and also in 25% of clinically normal at-risks. Correlation analysis of ERP components with detailed psychometry revealed a particularly high association of P3 latencies with measurements requiring speeded information processing in non-verbal tasks. P3 amplitude did not covary with performance scores but unlike P3 latency showed association with depression and psychosis scores. From the results it appears that analysis of ERPs is a useful electrophysiological tool for an objective assessment of cognition both in clinically definite and subclinical stages.

Adolescent↗
PubMedDate not supplied

His1069Gln and six novel Wilson disease mutations: analysis of relevance for early diagnosis and phenotype.

In the present study we examined 33 German and 10 Cuban unrelated Wilson disease (WND) index patients and their relatives. The common His1069Gln mutation accounted for 42% of all WND chromosomes in the German series and the haplotype C was found to be highly predictive for this mutation. Six WND gene mutations have not been described previously and involved a splice site at intron 18 (3903 + del1G), a termination codon in the copper-binding region of exon 2 (Cys271X), and missense mutations in transmembrane region 2 (Gly710Ala), in transmembrane region 3 (Tyr741Cys), in the DKTGT motif (Thr1031Ile) and in the ATP loop region (Gly1176Arg). In 15 German WND index patients and three sibs both WND mutations could be determined and a genotype-phenotype correlation was attempted. Patients homozygous for the His1069Gln mutation showed almost the complete range of clinical presentations, and thus in our study this mutation is not associated with a late, neurological presentation.

Base Sequence↗
PubMedDate not supplied

MRI of the brain in Wilson disease: T2 signal loss under therapy.

Repeat examinations in a de novo patient with Wilson disease revealed an expansion of decreased signal intensities in the basal ganglia on T2-weighted imaging after initiation of copper trapping therapy. Since marked clinical improvement was associated with continued urinary copper excretion, iron depositioning in exchange for copper might explain these findings.

Adult↗