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Biomedical subjects

R Gil

Publications and source records attributed to R Gil.

At least 127 records · Page 7Linked to original sources
PubMed1993

[Head-up tilt table test in patients with syncope of unexplained origin].

UNLABELLED: We studied 41 patients (21 m, 20 f) aged 22-70 years (mean 51) with syncope of unexplained origin using 60 degrees head-up tilt test (TT). Continuous ecg recording and direct arterial blood pressure were monitored. In case of positive response (e.g. syncope) in first examination next TT after administration of atropine (0.02 mg/kg) was performed. In first TT syncope was evoked in 19 patients (46%). Mean time from onset of tilt to syncope (TOS) was 15 +/- 13 min. Atropine administration protected against syncope during second TT in 7 patients, prolonged TOS in 4 (from 12 +/- 7 to 34 +/- 4 min) and shorted TOS (from 26 + 17 to 16 + 14 min) in the next 8 patients. We distinguished on that base: in 7 patients cardioinhibitory form, in 4 mixed form and in the next 8 patients vasodepressor form of vasovagal syndrome. We used in treatment: a) implantation of DDD or VVI pacemaker in 7 patients, b) clonidine in 8 patients, c) propranolol in 2 patients, d) derivates of atropine in 2 patients. During 1 year follow-up 14 patients are free of syncope and in the next 5 syncope occurred rarely. CONCLUSIONS: 1. Head up tilt test is very useful in diagnosis of syncope of unknown origin. 2. Second tilt after administration of atropine in patients with syncopal response in the first test helps to differ the type of vasovagal syndrome and to improve its treatment.

Adult↗
PubMed1993

[Carotid sinus massage in diagnosing syncope of unknown origin].

Carotid sinus massage (CSM) was performed in 44 patients (23 female, 21 male, mean age 52 years) with recurrent episodes of unexplained syncope and without any organic heart disease. The protocol of examination consisted of 5 s CSM performed unilaterally in supine, upright 60 degrees positions, after administration of propranolol (i.v. 0.1 mg/kg) and during autonomic inhibition (atropine i.v. 0.02 mg/kg after propranolol). The diagnosis of hypersensitive carotid sinus syndrome (HCSS) was established in case of pathologic response to CSM in supine and upright 60 degrees positions. Positive results of CSM was obtained in 15 (34%) examined patients. Cardioinhibitory form of HCSS was recognized in 9 and mixed form in 6 cases. Pathologically augmented carotid sinus reflex was provoked in 8 cases by massage of the right, in 4 cases of the left and in 3 both carotid sinuses. Maximal time of electrical asystole after CSM was 6300 ms while maximal decreased od systolic blood pressure was 70 mmHg. Intravenous administration of propranolol caused decrease of systolic blood pressure approximately 43 +/- 15 mmHg whereas the cardioinhibitory effect of CSM after this drug significantly was increased only in patients with a positive response to CSM in the supine or upright 60 degrees positions. Autonomic inhibition significantly decreased the cardioinhibitory effect of CSM without significant influence on its vasodepressive component.

Adult↗
PubMed1993

[Cerebral infarction, cardiac myxoma and lentiginosis].

Occlusion of the middle cerebral artery in a 16-year old woman revealed a left atrial myxoma associated with a mucocutaneous lentiginosis. Two-dimensional transthoracic or transesophageal echocardiography should be performed in all patients with stroke and lentiginosis to look for cardiac myxoma. After treatment of the cardiac tumor, echocardiography should be repeated at regular intervals to detect a recurrence of the myxoma. As this cardio-cutaneous syndrome is a familial disorder with autosomal dominant inheritance, examination of all family members by echocardiography is recommended.

Cerebral Infarction↗
PubMed1993

[Instantaneous pressure-velocity relationship of the coronary flow, alternative to coronary reserve measurement: a feasibility study and reproducibility of the method].

Animal experimentation has shown that the instantaneous pressure-velocity of coronary blood flow in the hyperaemic phase has a linear relationship. The slope of this regression evaluates coronary reserve independently of haemodynamic variables and the X-intercept (zero flow pressure or Pf = 0) determines the intra-myocardial back pressure which could influence the regulation of coronary flow. The object of this study was to evaluate the instantaneous pressure-velocity relationship of coronary flow in clinical practice and to analyse the reproducibility of this parameter. Forty-nine patients were divided into two groups, depending on whether their coronary arteries were angiographically normal (n = 34) or atheromatous with stenosis > or = 35% of the reference diameter (n = 15). Recordings of coronary flow velocity were made with a Doppler transducer mounted on a 0.018 inch guide wire. The slope of the diastolic linear segment of the pressure-velocity relationship was determined at the peak of papaverine-induced vasodilation from 4 consecutive cycles by a regression analysis. The pressure value at 0 flow was obtained by extrapolation of the regression slope to the axis of aortic perfusion pressure. A good quality spectral recording allowing reliable analysis of the velocity profile was obtained in 88% of cases (44/49). The high values of the correlation coefficient observed with each measurement of the slope confirm the applicability of linear regression analysis to the pressure-velocity relationship. The slope of the pressure-velocity relationship was significantly lower in patients with coronary stenosis (1.7 +/- 0.7 cm/s/mmHg in normal vessels versus 0.7 +/- 0.3 cm/s/mmHg in stenotic arteries, p < 10(-4)), and, similarly, the pressure at zero flow was also reduced (36.9 +/- 16 mmHg versus 25.5 +/- 12 mmHg, p = 0.03). A statistically significant correlation was observed between the slope values and coronary flow reserve but no correlation was demonstrated between the slope and intraluminal surface area of angiographically normal coronary arteries or the slope and degree of stenosis of atheromatous vessels. The linear regression slope and the pressure at zero flow were lower when the pressure-velocity relationship was measured during long diastolic periods induced by the injection of adenosine. In addition, the curvilinear appearances of the pressure-velocity relationship observed during these long periods suggest that the linear regression model is not applicable throughout the whole range of pressures and velocities, especially for the lowest values.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

[Doppler microprobe allows evaluation of local coronary circulation].

The local coronary flow in 42 patients (mean age: 59 +/- 9 years) with ischemic heart disease was assessed by means of an 0.018" intracoronary Doppler guidewire. Study population was divided into two groups: group I--"normal vessels" (diameter stenosis < 30%) and group II--"stenosis vessels" (diameter stenosis > 60%). Measurements of: averaged peak velocity (APV), diastolic-systolic velocity ratio (DSVR) were performed in proximal segments of normal vessels and proximally to stenosis in group II. APV and DSVR were recorded at rest (bas) and during papaverine induced hyperemia. Coronary flow reserve (CFR) was calculated as ratio hyperemic and resting values of APV. Mean value of APV at rest was highest for left main stem, lowest for venous by-passes (SVBG) but did not differ among three coronary arteries (LAD, LCX, RCA). CFR value was significantly higher for group I then for group II (2.75-3.3 vs 1.8-2.0) but did not differ significantly among particular arteries in both groups. Mean value of DSVRbas in both examined groups was lowest for right coronary artery and for SVBG (ca. 1.0) and did not change significantly during hyperemia. This value was significantly higher (ca. 2.0) for left coronary arteries (LAD, LCX) then for RCA and SVBG and significantly decreased after administration of papaverine.

Aged↗
PubMed1993

[Doppler microprobe for evaluation of coronary circulation after successful coronary angioplasty].

The influence of angiographically successful coronary angioplasty (PTCA) in 27 patients (mean age 64 +/- 8 years) was assessed by means of 0.018" intracoronary Doppler guidewire. Averaged peak flow velocity (APV) and diastolic-systolic velocity ratio (DSVR) were recorded in resting conditions (bas) and during papaverine induced hyperemia before and after PTCA. Coronary flow reserve (CFR) was calculated as ratio of hyperemic and resting APV. The parameters mentioned above were estimated proximally and distally to coronary stenosis to be dilated. Mean value of APVbas for distal part of the vessels was significantly lower (about 46-57%) then for the two proximal segments. PTCA caused significant increase of APVbas as for proximal (about 21-69%) as for distal segments (about 62-77%). That procedure caused significant increase of CFR only for right coronary artery (RCA). Mean values of DSVRbas in proximal position for left descendens (LAD) and left circumflex (LCx) arteries before PTCA were significantly higher than DSVbas for distal position but did not differ for RCA. PTCA caused significant increase of DSVRbas in distal position only for LAD and LCx. Our results showed that angiographically successful PTCA causes significant increase of APVbas for right and left coronary arteries and normalization of DSVRbas in distal segments of LAD and LCx.

Adult↗
PubMed1993

[Retrograde conduction (ventriculo-atrial) in patients with AV or intraventricular block. Electrophysiologic evaluation].

The purpose of the study was to evaluate ventriculoatrial conduction in patients with chronic complete AV block (AVB) (35 pts--gr. A), who were qualified for pacemaker implantation and in patients with bifascicular block (BFB) (20 pts--gr. B), who had electrophysiological study performed to determine indications for permanent pacing. Anterograde and retrograde conduction by accessory pathways were excluded in all patients. Incremental ventricular pacing (60-80 bpm to 200-220 bpm) and programmed ventricular stimulation were performed. Ventriculoatrial (VA) conduction was present in 12 of 35 patients in gr. A (34%) and in 15/20 patients in gr. B (75%). Mean VA conduction time was 192 +/- 50 ms in gr. A and 200 +/- 54 ms in gr. B, effective refractory period of right ventricle (ERP-RV) was 270 +/- 30 ms and 250 +/- 29 ms respectively. Mean retrograde Wenckebach point was 128 +/- 41 bpm in gr. A and 132 +/- 30 bpm in gr. B. The level of VA Wenckebach block in gr. A was found at AVN in 4 of 12 patients and in remaining was not directly recognised. Levels in gr. B were: AVN--6, not recognised--9 patients. Ventriculoatrial conduction shows complex properties and dependence on the type of ventricular stimulation. Electrophysiological study enables to find a level of retrograde block in some patients.

Adult↗
PubMed1992

Low resolution structure of microtubules in solution. Synchrotron X-ray scattering and electron microscopy of taxol-induced microtubules assembled from purified tubulin in comparison with glycerol and MAP-induced microtubules.

The structure of microtubules has been characterized to 3 nm resolution employing time-resolved X-ray scattering. This has revealed detailed structural features of microtubules not observed before in solution. The polymerization of highly purified tubulin, induced by the antitumour drug taxol, has been employed as a microtubule model system. This assembly reaction requires Mg2+, is optimal at a 1:1 taxol to tubulin heterodimer molar ratio, proceeds with GTP or GDP and is intrinsically reversible. The X-ray scattering profiles are consistent with identical non-globular alpha and beta-tubulin monomers ordered within the known helical surface lattice of microtubules. Purified tubulin-taxol microtubules have a smaller mean diameter (approx. 22 nm) than those induced by microtubule associated proteins or glycerol (approx. 24 nm), but nearly identical wall substructure to the resolution of the measurements. This is because the majority of the former consist of only 12 protofilaments instead of the typical 13 protofilaments, as confirmed by electron microscopy of thin-sectioned, negatively stained and ice-embedded taxol microtubules. It may be concluded that taxol induces a slight reduction of the lateral contact curvature between tubulin monomers. The main fringe pattern observed in cryo-electron micrographs is consistent with a simple 12 protofilament 3-start skewed lattice model. Cylindrical closure of this lattice can be achieved by tilting the lattice 0.8 degrees with respect to the microtubule axis. The closure implies a discontinuity in the type of lateral contacts between the tubulin monomers (regardless of whether these are of the -alpha-beta- or the -alpha-alpha-/-beta-beta- type), which indicates that lateral contacts and the subunit specificity of taxol binding are, to a large degree, equivalent.

Alkaloids↗
PubMed1992

[Idiopathic peripheral facial paralysis. Prognostic value of the combined study of the blink reflex with stimulation of the facial nerve. 91 cases].

The blink reflex and stimulodetection of the facial nerve was studied during the first ten days, the 30th and 60th day and at the end of the sixth month in 91 patients with Bell's palsy. In patients with present R1 during the first ten days, there was a remarkable tendency towards a satisfactory recovery without complications. On the contrary using this single test, it is impossible to determine with 100% accuracy, which Bell's palsy will have an unsatisfactory recovery with severe dysfunction. The blink reflex seems to be a useful test for predicting the prognosis in an early stage of the paralysis. The association of the blink reflex and stimulodetection of the facial nerve allows to evaluate the risk of sequelae by the means of different electrophysiological patterns.

Blinking↗
PubMed1992

[Cognitive evoked potentials and HIV infection].

Endogenous event-related potentials (and especially the P300 component) have delayed latencies relative to normal controls in patients with dementias of diverse aetiologies. Moreover, the subcortical varieties of dementia tend to affect also the early-stage N1 and P2 components whereas both types of dementias affect the later-stage N2 and P3 components. However it has become obvious that patients with HIV infection are susceptible to develop progressive, AIDS-related dementia, renamed 'HIV encephalopathy' by the Center for Disease Control. Several studies have shown that endogenous, but also early, components of long latency auditory evoked potentials are prolonged in latency in HIV-demented patients. However, these changes may also be present in class II and III patients and may permit the early recognition of HIV encephalopathy.

AIDS Dementia Complex↗
PubMed1992

[Comparative study by computerized EEG of dementia of the ALzheimer type and Parkinson's disease with dementia].

A computerized EEG (cEEG) study was performed in two groups of patients with dementia of the Alzheimer type (DAT) and with Parkinson's disease with dementia (PDD). Compared to control subjects suffering from Parkinson's disease without dementia, both groups demonstrated similar slowing down of background activity. However, there were more low frequency components, defined as between 2.5-7 Hz, and less topographical differentiation in PDD than in DAT. Furthermore, more severe impairment of cognitive functions was observed in DAT, but their psychometric score correlated with slowing down of EEG only in DMP. These observations emphasize the influence of the subcortical/cortical axis both in dementia of Parkinson's disease and in the neurophysiology of the EEG.

Aged↗
PubMed1992

Cholesterol embolism to the skin.

The clinical features of a patient with cholesterol embolism are presented. Histopathological examination showed the typical clefts of cholesterol in the skin and renal vessels. We believe this entity is under-reported in the dermatological literature.

Cholesterol↗
PubMed1992

[Sinus node in patients with atrioventricular and interventricular blocks. Electrophysiologic evaluation].

To assess the function of the sino-atrial node, electrophysiological study with pharmacological autonomic blockade was performed in 3 groups of patients: group I with a-v III zero or II zero type 2 heart block, group II with bifascicular interventricular blocks and group III-controls. Sino-atrial node electrogram was recorded in 81% of patients. Obtained results show, that sino-atrial node dysfunction is uncommon in patients with atrioventricular or interventricular blocks (8.6% and 15% respectively). Electrophysiological assessment of sino-atrial node function seems to be important in the consideration of patients with a-v or interventricular blocks for appropriate type of permanent pacing.

Adolescent↗
PubMed1992

[Neurological toxicity of amiodarone. 5 case reports].

Five patients developed neurological adverse effects as they were treated with amiodarone for 2 to 18 months. The daily maintenance dose did not exceed 400 mg. The neurological manifestations included tremor, ataxia, peripheral neuropathy, dyskinesia, myoclonic jerks, extrapyramidal hypertony, and altered mental status. These side effects resolved within 3 days to 3 months after amiodarone withdrawal. Advanced age, renal failure, diabetes mellitus, and alcoholism seemed to be risk factors for development of amiodarone neurotoxicity. Both peripheral and central nervous systems are involved in these amiodarone-induced complications.

Age Factors↗
PubMed1992

[Mitral valve prolapse. Atrial stimulation, ajmaline test and "pharmacological denervation" in the evaluation of ventricular repolarization].

In patients with mitral valve prolapse syndrome (MVP) various electrophysiological abnormalities occur. There are convergent opinions concerning QT distance variability and the influence of autonomic nervous system on ventricular repolarization in this syndrome. In 38 MVP patients (group I) and 24 subjects without this abnormality (group II) ecg was recorded during transvenous right atrial pacing at baseline, after ajmaline administration and after pharmacological autonomic blockade (atropine + propranolol). The following ventricular repolarization parameters were analysed: QTe (distance to the end of T wave), JTe (distance between J point and the end of T wave--so called "pure repolarization"), QTdys (repolarization dispersion) and the corrected QTc.QTe during 90/min right atrial pacing was significantly shorter than QTc in both groups. QTc was abnormally prolonged (above 440 msec) in MVP group. Ajmaline administration prolonged QTe in group II only, whereas autonomic blockade resulted in marked shortening of QTe in MVP group. QTdys was significantly prolonged only after ajmaline administration in group II. Based on above results, the following conclusions are made: 1) Right atrial pacing technique may be used for calculating standardized QT distance, an alternative to corrected QT. 2) Ajmaline test is useless in ventricular repolarization estimations in MVP patients. 3) In MVP patients the influence of adrenergic system on ventricular repolarization at rest appears to be greater than in non-MVP subjects.

Adolescent↗