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Biomedical subjects

E Simon

Publications and source records attributed to E Simon.

At least 37 records · Page 2Linked to original sources
PubMed1999

Heat acclimation and hypohydration: involvement of central angiotensin II receptors in thermoregulation.

This investigation attempted to confirm the involvement of central ANG II-ergic signals in thermoregulation. Experiments were conducted on rats undergoing short (STHA)- and long (LTHA)-term heat acclimation, with and without superimposed hypohydration. Vasodilatation (VTsh) and salivation (STsh) temperature thresholds, tail blood flow, and heat endurance were measured in conscious rats during heat stress (40 degrees C) before and after losartan (Los), an ANG II AT(1)-selective receptor antagonist, administration either to the lateral ventricle or intravenously. Heat acclimation alone resulted in decreased VTsh. STsh decreased during STHA and resumed the preacclimation value, together with markedly increased heat endurance on LTHA. Hypohydration did not affect this biphasic response, although STsh was elevated in all groups. The enhanced heat endurance attained by LTHA was blunted. Neither Los treatment affected the nonacclimated rats. In the heat-acclimated, euhydrated rats, intracerebroventricular Los resulted in decreased VTsh, whereas intravenous Los resulted in elevated STsh. Both intracerebroventricular and intravenous Los led to markedly enhanced heat endurance of the LTHA hypohydrated rats. It is concluded that the LTHA group showed a loss of the benefits acquired by acclimation on hypohydration, whereas the STHA rats, which show an accelerated autonomic excitability in that phase, gained some benefit. It is suggested that ANG II modulates thermoregulation in conditions of chronic adjustments. Central ANG II signals may lead to VTsh upshift, whereas circumventricular structures, activated via circulating ANG II, decrease STsh. On hypohydration these responses seem to be desensitized.

Acclimatization↗
PubMed1999

Thermoregulation as a switchboard of autonomic nervous and endocrine control.

Analyzing the multiple effectors of autonomic temperature regulation has, sometimes unexpectedly, provided insights into the characteristics according to which the non-thermoregulatory functions of these effectors are controlled. This article reviews the sympathetic control of cardiovascular and immune functions, hormonal control of energy balance and neurohormonal control of salt and fluid balance inasmuch as they are challenged by competing demands of thermoregulatory requirements. These interactions are taken as examples for the analytical power of the experimental conception to challenge non-thermoregulatory control systems with thermoregulatory activation, and vice versa. Animal models carrying spontaneous or intentionally produced gene defects and molecular and histochemical techniques of gene identification and neuronal tracing are becoming increasingly important. They are applied, in connection with physiological studies exploiting mutual interactions of autonomic control systems, with the aim to elucidate the cytoarchitecture of neuronal circuits by which specific autonomic regulatory activities are controlled.

Animals↗
PubMed1999

[Status of problems with administration of hormonal contraceptives].

Following the application of oral hormonal contraceptives situations may occur which need fast clarification. In this report we discuss the practical aspects of forgetting to take hormonal contraceptives, the risk for birth defects, the time when to restart taking oral contraceptives after delivery and abortion, the indications for stopping the application, the taking of oral contraceptives under anticoagulant therapy, the behaviour during migraine, the raising need of ethinylestradiol in the case of epilepsy, the procedure in case of oligophrenia, the prevention of the rheumatoid arthritis as well as special questions in cases of diabetes mellitus and gestational diabetes.

Contraceptives, Oral, Hormonal↗
PubMed1999

Cervico-facial necrotising fasciitis occurring with facial paralysis: case report.

Necrotising fasciitis is a soft tissue infection, usually polymicrobial, characterised by necrosis of fascia and subcutaneous tissue. It frequently involves the groin, abdomen and extremities, but rarely involves the cervico-facial region. A case is presented of a 70-year old man who, following a futile attempt to extract a lower left first molar, developed a cervico-facial necrotising faciitis with facial nerve paralysis. Bacteriological investigations revealed the presence of Klebsiella spp and viridans streptococci. It is emphasized that early detection of this disease followed by aggressive surgical debridement and antibiotic therapy are most important.

Aged↗
PubMed1999

Laparoscopic cholecystectomy in acute cholecystitis.

The authors retrospective analyze the role of golden standard laparoscopic cholecystectomy for the treatment of acute cholecystitis. They make a comparison between the results of 50 early cholecystectomy and 44 "a froid" cholecystectomy (operation was postponed until 6 weeks after acute cholecystitis had healed). From January 1997 to December 1998 536 laparoscopic cholecystectomies were performed. In 491 cases (91.6%) laparoscopic, and in 45 cases (8.4%) traditional (opening) method was indicated. Converted cholecystectomies were in 36 cases (7.3%). Agreeing to the literature they can determine the optimal timing of the operation in 72 hours from the onset of acute cholecystitis [2, 4]. In this group (first group) there were 50 cases, with 14 conversions (28%). In the second group (postponed, so called "a froid" phase) there were 44 patients. From this group was the intraoperative diagnosis serious acute-subacute cholecystitis in 24 cases (54.54%) causing complicated laparoscopic cholecystectomy and resulting in 11 conversions (11/44: 25%). The causes of the higher rate of conversion were the grave inflammation and slow dissection of central formation. There were no serious complication and mortality in both groups. It was diagnosed bile leak (two cases) which ceased spontaneously, one haematoma in abdominal layers, and one trocar's hernia. The authors have recommended the laparoscopic cholecystectomy for early diagnose acute cholecystitis in order to prevent the complications and reduce the sick-leave. Supporting their viewpoint the most important clinical end economical facts are: the recurrence of inflammation forced urgent surgery and caused more complication in the course of "a froid" phase there were scrutable anatomical situation the patients recovered in a shorter time.

Acute Disease↗
PubMed1999

The laparoscopic technique for bilateral inguinal hernias.

From March 1994 to March 1999 359 laparoscopic hernioplasties have been performed on 295 patients. In 349 cases (97.2%) TAPP (transabdominal preperitoneal), in 10 cases (2.8%) TEP (total extraperitoneal) method was used for the treatment. In 64 cases (21.7%) bilateral hernias were operated using TAPP-method only. There were 15 hidden hernias and 14 recurrences on the contralateral side in this group. The hernial ring was covered with two smaller meshes or one bigger. There were no intraoperative complications. In 21 cases (32.8%) subcutaneous emphysema and in 3 cases (4.6%) sero-haematoma was developed. The emphysemas were solved spontaneously in 2-3 hours after the surgery. One haematoma was needed punction. The patients were discharged from the hospital on the second or third postoperative day. The authors found that the bilateral laparoscopic hernioplasty much more favourable for the patients.

Adolescent↗
PubMed1999

Synchronically performed laparoscopic cholecystectomy and hernioplasty.

Cholecystectomies and hernioplasties are the two most frequently performed surgical interventions. The laparoscopic technique can be offered for the simultaneous treatment with both operating indications. The synchronical operation can give all the advantages of the minimally invasive technique. Authors had performed laparoscopic cholecystectomy with laparoscopic hernioplasty in five cases. Two inguinal and three postoperative hernias were reconstructed. The cholecystectomy was performed with a "three punction method", and the hernioplasty by using the same approach, completed by inserting a fourth assisting trocar as required. The hernial ring was covered with an intraperitoneally placed mesh, which was fixed by staplers (the so-called "IPOM-method": intraperitoneal on-lay mesh). There was no intra-, nor postoperative complication. The hernioplasty combined with laparoscopic cholecystectomy did not have effect on postoperative pain and nursing time. The return to the normal physical activity was short, similar to laparoscopic hernioplasty (in 1-2 weeks). Authors conclude that the simultaneous, synchronous laparoscopic cholecystectomy and hernioplasty is recommended and should be the method of choice because it is more advantageous for patients.

Adult↗
PubMed1998

Differential stimulation of c-fos expression in hypothalamic nuclei of the rat brain during short-term heat acclimation and mild dehydration.

Activation of central nervous structures involved in the perception and integration of thermo- and osmoregulatory signals was investigated in the Sabra rat. Male rats were either non-treated (C-E), water-deprived for 24 h (C-D), short-term acclimated to 34 degrees C for two days (STHA-E) or subjected to both stimuli (STHA-D). Immunoreactivity for c-Fos protein (Fos-IR) as marker for neuronal activation was quantified in (extra-)hypothalamic structures: organum vasculosum laminae terminalis (OVLT); subfornical organ (SFO); medial (MPA), ventromedial preoptic (VMPO) and lateral hypothalamic (LHA) areas; median preoptic (MnPO), magnocellular supraoptic (SON) and paraventricular (mPVN) nuclei; limbic lateral septal (LS) and thalamic paraventricular (PV) nuclei. Compared to C-E rats, dehydration markedly increased Fos-IR exclusively in neurons of the OVLT, SFO and MnPO known to be involved in osmoreception, in the mPVN and SON, and to a minor extent in the VMPO. The VMPO, MPA, LHA and LS-important (extra-)hypothalamic sites for the perception and integration within the thermoregulatory control circuit-exhibited intense elevation of Fos-IR upon short-term heat acclimation. Of all (extra-)hypothalamic structures involved in central osmoregulation, only the MnPO revealed heat-induced Fos-IR in numerous cells located preferentially in its rostral component. Thus, the MnPO proved to be activated during both thermal and osmotic stimulations applied separately. Subjected to the combined stress (STHA-D), most brain structures investigated showed striking Fos-IR due to thermally enhanced osmotic stimulation, with additive effects demonstrated in the MnPO. The data support differential central activation of c-fos expression due to thermal or osmotic stimulations, with the MnPO acting as putative integrative center for both autonomic control circuits.

Acclimatization↗
PubMed1998

Nitric oxide as a peripheral and central mediator in temperature regulation.

In animals including humans nitric oxide (NO) serves as a biological messenger both peripherally at neuroeffector junctions and in the central nervous system where it modulates neuronal activity. Evidence for the involvement of NO in homeostatic control is accumulating also for temperature regulation in homeotherms. In the periphery an auxiliary role in the vasomotor control of convective heat transfer to heat dissipating surfaces and modulation of thermoregulatory heat generation, especially in brown adipose tissue as the site of nonshivering thermogenesis, are discussed as NO actions. At the central level a thermolytic role of NO in thermoregulation as well as in fever is assumed, however, experimental data opposing this view suggest that topical specificity may be important. At the level of single neurons, the observed interrelationships between thermosensitivity and responsiveness to NO are still not consistent enough to reconcile these data with the effects of NO-donors and inhibitors of NO-synthase on temperature regulation.

Animals↗
PubMed1998

Erythrocyte antioxidant status in asymptomatic hypercholesterolemic men.

An imbalance between antioxidant and oxidant-generating systems leading to an oxidative stress has already been proposed in the pathogenesis of atherosclerosis. In the present study we investigated the antioxidant status in 60 asymptomatic hypercholesterolemic (HC) men compared with 48 normocholesterolemic (NC) men. Hypercholesterolemic subjects had a significantly lower red blood cell vitamin E (vit E-RBC) content in spite of their normal total plasma and HDL vitamin E concentrations. Activities of erythrocyte superoxide dismutase and glutathione peroxidase were not significantly different between groups. We also determined the resistance of RBCs to an oxidative stress by determining the extent of hemolysis induced by a water-soluble azo-compound. This resistance was significantly decreased in HC men compared with NC subjects. These results demonstrate an altered antioxidant status of RBC in asymptomatic HC men associated with an increased erythrocyte susceptibility to an oxidative stress. The measure of the vitamin E content in RBC might be the most sensitive parameter for evidencing early oxidative stress which does not need an adaptation of enzymatic protective systems.

Adult↗
PubMed1998

Spinal neuronal thermosensitivity in vivo and in vitro in relation to hypothalamic neuronal thermosensitivity.

In the spinal cord, temperature signals are generated which serve as specific inputs in the central nervous control of body temperature. Because of the spatially distinct organization of afferent and efferent neuronal systems at the spinal level, the afferent pathway for temperature signal transmission could be identified in vivo in the ascending, anterior and lateral tracts with a relationship of about 75:25% between warm and cold sensitive neuraxons. Analysis of spinal neuronal thermosensitivity in vitro on spinal cord tissue slices has been concerned, so far, with the superficial laminae of the dorsal horn as the site of origin of ascending nerve fibers conveying mostly temperature and pain signals, and with lamina X as a site of origin of afferent as well as efferent neurons. A relationship of about 95:5% between warm and cold sensitive neurons was found at the segmental level, indicating that warm sensitivity is the prevailing, primary property of spinal neurons, whereas cold sensitivity seems to be mainly generated by synaptic interaction as a secondary modality. Dynamic responses to temperature changes were frequently displayed in vitro at the spinal segmental level in lamina I + II but not in lamina X, even by neurons whose static activity was little influenced by local temperature. Dynamic thermosensitivity was found less frequently in ascending tract neuraxons and was not observed in hypothalamic neurons receiving temperature signal inputs from the spinal cord, and thus, does not seem to be relevant for the thermosensory function of spinal cord neurons, unlike peripheral warm and cold receptors. A majority of spinal warm sensitive neurons displayed both static and dynamic warm sensitivity as an inherent property after synaptic blockade. In the further analysis of spinal cord thermosensitivity, the in vitro approach permits application of the same electrophysiological and neuropharmacological methods as were established for the analysis of hypothalamic thermosensitivity. In addition, the topography of the spinal cord will provide additional structural and possibly histochemical information to characterize the functions of neurons independently of their thermal properties.

Animals↗
PubMed1998

Energy restriction with high-fat diet enriched with coconut oil gives higher UCP1 and lower white fat in rats.

OBJECTIVE: To investigate the effects of overfeeding on a high fat diet, enriched in coconut oil, and the influence of food restriction on the uncoupling protein (UCP1) expression and on body fat content. DESIGN AND SUBJECTS: In experiment I, female Wistar rats were fed ad libitum either a normal-fat diet (control group, C) or a high-fat diet (HF), enriched in coconut oil, for 7 weeks. In experiment II, HF rats after finishing experiment I were fed (for 3 weeks) either the normal-fat diet (group CAHF, Control After High Fat) or food restricted diets which provided 60% of the energy intake of group CAHF: a group fed a low-energy, normal-fat diet (LENF) and another fed a low-energy, high-fat diet (LEHF). MEASUREMENTS: Body and fatty depot weights. Food intake. Protein and UCP1 levels of interscapular brown adipose tissue. RESULTS: High-fat diet feeding promoted an increase in body fat content, body weight and UCP1 levels. Energy restriction induced similar body weight reduction in groups LENF and LEHF. However, some adipose depots were more strongly reduced in the rats fed the high-fat diet enriched in coconut oil (group LEHF) than in the rats fed the normal-fat diet (Group LENF). Specific UCP1 was 2.0 (group LENF) and 3.4 (group LEHF) times higher than in controls (group CAHF). CONCLUSION: The coconut-oil enriched diet is effective in stimulating UCP1 expression during ad libitum feeding and in preventing its down regulation during food restriction, and this goes hand in hand with a decrease of the white fat stores.

Adipose Tissue↗
PubMed1998

Myeloma light chains are ligands for cubilin (gp280).

Although myeloma light chains are known to undergo receptor-mediated endocytosis in the kidney, the molecular identity of the receptor has not been characterized. We examined the interaction between cubilin (gp280) and four species of light chains isolated from the urine of patients with multiple myeloma. Four lines of evidence identify cubilin, a giant glycoprotein receptor, which is restricted in distribution to endocytic scavenger pathways and which has potent effects on endosomal trafficking, as a potentially physiologically relevant binding site for light chains: 1) light chains coeluted during immunoaffinity purification of cubilin; 2) polyclonal antisera to cubilin but not control sera, displaced human light chain binding from rat renal brush-border membranes; 3) cubilin bound to multiple species of light chains during surface plasmon resonance; 4) anti-cubilin antiserum interfered with light chain endocytosis by visceral yolk sac epithelial cells. However, both binding of light chains to brush-border membranes and endocytosis of light chains by yolk sac epithelial cells were only partially inhibited by anticubilin antibodies, suggesting presence of additional or alternate binding sites for light chains. Excess light chain had a potent inhibitory effect on endosomal fusion in vitro. Binding showed dose and time-dependent saturability with low-affinity, high-capacity equilibrium binding parameters. These data demonstrate that cubilin plays a role in the endocytosis and trafficking of light chains in renal proximal tubule cells.

Amino Acid Sequence↗
PubMed1998

[Vasculitis affecting the kidney: analysis of 18 patients].

OBJECTIVE: Eighteen patients who were judged to have systemic vasculitis (1990 American College of Reumathology criteria) affecting the kidney, from January 1988 to August 1996, were reviewed. METHOD: We analyzed characteristics of clinical, biochemical, histopathological features, the interval between the onset of the symptoms to a diagnosis of disease, treatment and overall outcome. RESULTS: The principal mode of presentation of the vasculitis is general, renal and pulmonary symptoms. The discovery of ANCA has improved the diagnostic procedure in patients with these diseases. Renal biopsy facilitates early diagnosis, prognosis and treatment. The renal lesion typically shows a segmental necrotizing glomerulonephritis and extracapillary proliferation forming crescent. CONCLUSIONS: The systemic vasculitis with renal involvement carries a poor prognosis and high mortality. A variety of treatment has been employed, but their precise role in the management of these vasculitis is still being elucidated.

Aged↗
PubMed1998

Dose response and concentration response relationship of apomorphine in patients with Parkinson's disease and end-of-dose akinesia.

The motor response and the PK-PD relationship of the dopamine agonist, apomorphine, after ascending single doses (0.5, 1, 2, 4 mg s.c.), was investigated in 10 patients with advanced Parkinson's disease presenting end-of-dose motor fluctuations. Aim of the study was to investigate the exact pharmacodynamic effects of different apomorphine doses on the magnitude and duration of motor responses in parkinsonian fluctuators. The average improvement in the magnitude of the motor response (% change of baseline score in the Columbia University Rating Scale) elicited by apomorphine was negligible with 0.5 mg, 10% after the 1 mg dose, 22% after 2 mg, and 25% after 4 mg. If a 20% improvement is considered clinically relevant, a response was seen in 0/10 patients (0.5 mg), 2/10 patients (1 mg), 6/10 patients (2 mg), and 6/8 patients (4 mg). The duration of response was about 0.25 h (1 mg), 0.58 h (2 mg), and 0.72 h (4 mg). An explorative analysis of individual plasma concentration vs. effect curve, yielded a steep, sigmoidal concentration effect relationship with fast equilibrium at the effect site. The EC50 of the individual curves averaged 20 pMol/ml. However, several curves exhibited proteresis, making the application of a PK-PD model impossible. The reason for proteresis is not clear, it might indicate acute tolerance as well as a redistribution of apomorphine from the effect site.

Adult↗
PubMed1997

[Otothermometry].

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Body Temperature↗