Search PubMed⌕ Search

Biomedical subjects

J Bogacz

Publications and source records attributed to J Bogacz.

18 recordsLinked to original sources
PubMed2002

MCP-N (LiF:Mg,Cu,P) TLDs for radon measurements with charcoal canisters.

A method of measurement of radon concentration in air was developed, based on high-sensitivity LiF:Mg,Cu,P (MCP-N, TLD Poland) thermoluminescent detectors installed in charcoal canisters. The canisters were exposed typically for 72 h in a calibration chamber with a radon concentration ranging from 100 Bq x m(-3) to 87 kBq x m(-3). It was found that in these conditions the signal registered by the TL detectors was proportional to the 222Rn concentration and the lowest limit of detection (LLD) was at a level of 100 Bq x m(-3). The proposed method can be used in large-scale, multi-site surveys aimed at screening for high levels of indoor radon concentration or for measuring ground radon exhalation rates.

Charcoal↗
PubMed2000

Oculomotor phenomena in petit-mal.

OBJECTIVE: To determine the temporal relationship among behavior, eye movements and respiration during absence seizures. METHOD: This included simultaneous videorecording of a patient's face, EEG and respirogram, in 5 patients with absence seizures. Absence seizures were defined as a sudden lapse of consciousness with impairment of mental functions. Oculomotor phenomena consisted of: eye fluttering, eye deviation (conjugate lateral or upward deflection), and eye-opening. RESULTS: Oculomotor phenomena began 1 2/3-3 s after the onset of the electrographic discharge and ended before the discharge. The most frequent events were eye-opening, stare with or without palpebral myoclonias, and tonic or clonic upward movements. Downward movement or convergence was not observed as well as head version. Respiratory changes (apnea) are the last events to occur. CONCLUSIONS: absence seizures were characterized by the onset of a 3/s spike-slow wave discharge followed by oculomotor phenomena and respiratory changes. The time course suggests that epileptic discharges precede and then involve oculomotor and respiratory brainstem centers.

Child↗
PubMed1984

Visual evoked potentials and brain stem auditory potentials in Friedreich's ataxia--a longitudinal study.

Six patients with Friedreich's ataxia, 4 males and 2 females, their ages ranging from 13 to 33 years, were studied. The early manifestations started between age 7 and 13 with an evolution time between 6 and 20 years. Serial visual and brain stem auditory evoked potential recordings were made. A progressive increase in latency, reduction in amplitude and in latency inter-ocular difference of P100 were observed. The pattern of the reversal checker-board visual evoked potential was preserved. A disorganized BAEP pattern, a well defined potential I, a very small potential V and a delay in the interpeak latency were constant findings. The assumption is made of a progressive involvement of both visual and central auditory pathways. Pathophysiological mechanisms are discussed.

Adolescent↗
PubMed1984

Familial spastic ataxia associated with Ehlers-Danlos syndrome with platelet dysfunction.

Four members of a family with consanguineous relationships, the proband and his three children (2 sons and 1 daughter) are affected with Familial Spastic Ataxia and with Ehlers-Danlos' Syndrome with platelet aggregation dysfunction. In the four cases, this exceptional association appears remarkably homogeneous both in clinical and laboratory studies. The two syndromes are of dominant-autosomic transmission and probably originated in a new mutation which presumably maintained a genetic linkage. Spastic ataxia is characterized by a precocious onset and a slow evolution. The first-born son shows a dominant pyramidal syndrome with mild ataxia suggesting that it is a transitional form of familial spastic paraplegia. The Ehlers-Danlos syndrome pertains to form II or "mitis" with moderate skin hyperelasticity and joint hypermobility. The abnormal platelet aggregation curves have the same profile in all the patients. The first-born son also presents a mitral valve prolapsus as we may find either in Ehlers-Danlos syndrome or in spastic ataxia. The neurophysiological, tomographical, histological, ultrastructural and biochemical studies attempt to accomplish a better definition of these associated nosological entities.

Adolescent↗
PubMed1981

Saccadic eye movements in frontal lesion and posthemispherectomy in humans. An electro-oculographic study.

This study was concerned with the assumed role that the frontal eye fields could play in the mechanisms of: the voluntary saccade optokinetic responses. Ten patients with frontal lobe tumors (8 unilateral, 2 bilateral) and two patients with a right hemispherectomy were studied. EOG and EEG were performed in the same session. Left and right voluntary saccadic potentials could be recorded in all cases, no matter where the frontal lesion was located. Minor differences in amplitude were observed between the fast eye movement to the lesion and to the normal side. Horizontal optokinetic responses to a moving drum were a constant finding in all cases. The frequency and amplitude of the fast component of the responses did not show substantial differences with the drum moving to the lesion or to the healthy side. Voluntary saccadic eye movements to the left and left horizontal optokinetic responses to a moving drum to the right, were recorded in the two cases with a right hemispherectomy. The hypothesis that considers frontal eye field as the pulse generator area for the voluntary or reflex saccadic eye movements is discussed.

Brain↗
PubMed1979

Electro-oculographic and electroencephalographic correlative study of optokinetic responses in brain lesions.

Electro-oculograms of induced optokinetic responses (OKR) and EEG were recorded in 61 patients with either left or right hemisphere lesions. Of the 61 patients 55 showed focal EEG disturbances as follows: occipito-temporal (7 cases), parieto-temporal (10 cases), occipito-parieto-temporal (26 cases), temporal (9 cases) and frontal (3 cases). Symmetric OKR (21 cases) were recorded when no EEG changes were observed or when these were localized to left or right temporal and frontal electrodes and exceptionally when unilateral occipital and parietal regions were also involved. In 40 cases with unilateral hemispheric lesion a contralateral abnormal OKR was observed. Low frequency OKR with or without amplitude changes, especially of fast (saccadic) component, was mainly observed in parietal localization. In severely disturbed OKR, i.e. random jerks, the abnormal brain waves were mainly localized to the occipito-parieto-temporal region. In all cases in which no response was obtained the affected area was the occipito-parieto-temporal. These findings are discussed with reference to the regulating systems of slow (smooth) and fast (saccadic) eye movements triggered by visual stimuli.

Adolescent↗
PubMed1977

[Ocular diskinesia].

The clinical findings and the electro-oculogram were correlated in four cases (3 postinfectious, 1 vascular) with ocular dyskinesias, of a mixed type in two of them. This correlation led to a more precise recognition of the pattern of opsoclonus, flutter and ocular dysmetria. Ocular dyskinesias have certain resemblances with voluntary saccadic movements; the effects of ocular following and optokinetic stimulation are described. The role of brainstem and cerebellar structures in relation with the physiopathology of these dyskinetic ocular movements is discussed.

Adult↗