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Biomedical subjects

J M Michel

Publications and source records attributed to J M Michel.

At least 37 records · Page 2Linked to original sources
PubMed1997

Metabotropic glutamate receptors in the rat nucleus accumbens.

The effects of glutamate metabotropic receptors (mGluRs) on excitatory transmission in the nucleus accumbens were investigated using electrophysiological techniques in rat nucleus accumbens slices. The broad-spectrum mGluR agonist (1S,3R)-1-aminocyclopentyl-1,3-dicarboxylate, the mGluR group 2 selective agonists (S)-4-carboxy-3-hydroxyphenylglycine, (1S,3S)-ACPD) and (2S,1'S,2'S)-2-(2'-carboxycyclopropyl)glycine (L-CCG1), and the mGluR group 3 specific agonist L-2-amino-4-phosphonobutyrate (L-AP4) all reversibly inhibited evoked excitatory synaptic responses. The specific group 1 mGluR agonist (R,S)-3,5-dihydroxyphenylglycine [(R,S)-DHPG] did not depress transmission. Dose-response curves showed that the rank order of agonist potencies was: L-CCG1 > L-AP4 > (1S,3S)-ACPD. Group 2 and 3 mGluRs inhibited transmission via a presynaptic mechanism, as they increased paired-pulse facilitation, decreased the frequency of miniature excitatory postsynaptic currents and had no effect on their amplitude. The mGluRs did not inhibit transmitter release by reducing voltage-dependent Ca2+ currents through N- or P-type Ca2+ channels, as inhibition persisted in the presence of omega-conotoxin-GVIA or omega-Aga-IVA. The depression induced by mGluRs was not affected by specific antagonists of dopamine D1, GABA-B or adenosine A1 receptors, indicating direct effects. Finally, (R,S)-DHPG specifically blocked the postsynaptic afterhyperpolarization current (I(AHP)). Our results represent the first direct demonstration of functional mGluRs in the nucleus accumbens of the rat.

Adenosine↗
PubMed1996

Swan-Ganz catheter induced pulmonary artery perforation during cardiac surgery concerning two cases.

Two case reports describing patients having cardiac operations under extra corporeal circulation are presented. At the completion of the operation, a massive hemoptysis occurred in both patients after a Swan-Ganz catheter had perforated the pulmonary artery. A hemostasis lobectomy was then immediately required. The immediate and long term prognosis seems satisfactory. This is an unusual but serious complication. The incidence of this complication varies between 0.06 and 0.2%. The more frequently related risk factors include people over the age of 60, pulmonary artery hypertension, anticoagulant therapy, hypothermia and manipulation of the heart by the surgeon. When this accident occurs, many authors suspect the balloon. An early diagnosis is essential in the case of a major or even a minor hemoptysis, because this complication may be a lethal one as the mortality rate may reach 50%. According to us, the appropriate therapy which would reduce this mortality is a surgical one (hemostasis lobectomy).

Aged↗
PubMed1996

[Results of surgical treatment of hepatic metastasis of colorectal origin].

Surgery is the only treatment which can achieve long-term survival of patients with colorectal liver secondaries. This study reports the results in 71 patients with liver metastases who underwent hepatic resection from January 1980 to December 1994. The mean age was 60 years (range 37 and 80 years). Operations included 33 right hepatectomies, 5 extended right hepatectomies, 6 left hepatectomies, 11 left lobectomies,. Surgery was macroscopically and microscopically curative in 61 patients. Information was not available in 2 patients. Significant morbidity was observed in 37% of patients. Actuarial survival at 1, 3 and 5 years was 83%, 27% and 20% respectively. At the end of the follow-up, 50 patients had died and 6 were lost to follow-up. Techniques of hepatic resection for secondaries are well established and postoperative mortality is low. Pending advances in chemotherapy, we recommend surgery as being the only way of improving long-term survival in patients with colorectal hepatic metastases.

Adult↗
PubMed1987

[Propofol in the surgery of the aortic bifurcation. Comparison with isoflurane].

Two groups of nine patients each, all undergoing surgery for aorto-bifemoral prosthesis, were studied. They were premedicated with 10 mg morphine and 1 mg flunitrazepam. A Swan-Ganz catheter was then inserted. Cardiac output was measured by thermodilution. Haemodynamic parameters were measured before induction (t0), 15 min after intubation (t1), 10 min after the start of the surgical procedure (t2), 5 min before clamping the aorta (t3), whilst the aorta was clamped (t4), and a few minutes after unclamping. Group A received 2 mg X kg-1 propofol at induction, anaesthesia being maintained with 100 micrograms X kg-1 X min-1 propofol. Group B received 4 mg X kg-1 thiopentone, followed by isoflurane at the dose of 0.9 vol. %. Both groups received 5 micrograms X kg-1 fentanyl and 0.1 mg X kg-1 vecuronium to ease intubation. Artificial respiration was carried out with a mixture of 40% oxygen and 60% nitrous oxide. The fall in blood pressure between t2 and t3 was significantly more important in the propofol group (-16%). In the same group, the systolic blood pressure and heart rate fell by 23 and 19% respectively after induction (p less than 0.05); the cardiac index fell by 20% and the systemic vascular resistances did not change. The fall in blood pressure, heart rate and cardiac index were not significant for group B. The haemodynamic changes due to clamping of the aorta were not significant between or within groups. In group A, one patient presented with bradycardia, hypotension and myocardial ischaemia, and another died of postoperative ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

[Phonomechanographic evaluation of left ventricular function in hyperthyroid states].

Hyperthyroidism is associated with a hyperkinetic syndrome, the mechanisms of which are not fully understood but which include an increase in heart rate, a reduction in systemic arterial resistance and a debatable increase in myocardial contractility. The limitations of radioimmunological assay of the hormonal mediators underline the diagnostic value of an atraumatic method of quantifying left ventricular systolic function. In view of the variable sensitivity of phonomechanographic and echocardiographic indices with respect to changes in heart rate, pre- and after load, we studied apex cardiographic indices during the phase of isovolumetric contraction. Fifty-eight patients with hyperthyroidism but without patent cardiovascular disease were divided into two subgroups: Grave's disease: 38 cases, and toxic adenoma: 22 cases. The results of the measurements of systolic time intervals and the calculation of "indices of contractility" obtained from the apex cardiogram and its first derivative, were compared with those of 36 young, normal subjects. The results show that: the pre-ejection period of the study population was much shorter than normal (65,7 ms +/- 2,5 vs 84,6 ms +/- 3,4; p less than 0,001); this was clearly related to the chronotropic factor (p less than 0,05). The pre-ejection/ejection period ratio did not differentiate hyperthyroid from normal subjects (0,265 vs 0,283, p greater than 0,20), except in Graves' disease (0,249, p less than 0,02). On the other hand, measurements made from the apex cardiogram showed significant differences in both types of hyperthyroidism. (Formula: see text). In conclusion, phonomechanography may be used to quantify the increase in left ventricular function in hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Must acute carotid thrombosis be surgically treated? 1962-1973: long-term results].

A study of long-term results (mean follow-up: 10.6 years) in 22 patients operated on for acute carotid thrombosis between 1962 and 1973 is reported. In most instances, surgery was performed at the acute phase of a massive cerebrovascular occlusion, usually more than 8 hours after onset (10 cases). Five of these patients (22%) died in the postoperative period. Eight (35%) recovered without residual disease. In six, the condition improved, while it remained unchanged or worsened in three (14%). There were ten delayed deaths, including two from a recurrent cerebrovascular episode and four from cardiac disease. The actuarial survival curve does not differ from that of patients treated conservatively, with rates being 60% at five years, 36% at ten years and 28% at thirteen years. The quality of certain postoperative results suggests that surgical indications at the acute stage of carotid occlusion be reviewed. The study of thirty series from the literature (1 046 cases) shows a 17% mortality rate, while 50% of patients recover or improve. This mortality is significantly lower in recent statistics, under 10%: this improvement may be ascribable to more rigid surgical indications (delay under 6 hours, operation in variable neurologic deficiencies, early diagnosis by the Doppler procedure, better postoperative management). The authors conclude that surgical management of acute carotid thrombosis should no longer be systematically dismissed.

Acute Disease↗
PubMed1983

Two half-siblings with tuberous sclerosis, polycystic kidneys and hypertension.

Two half-brothers with tuberous sclerosis (TS) presented with polycystic kidneys in early childhood, before the classical stigmata became apparent. Their father shows no evidence of the disease. The older boys subsequently developed adenoma sebaceum at nine years and the younger boy developed infantile spasms. Hypertension occurred in both cases but neither showed evidence of renal failure. Extensive renal cyst formation in TS is rare, but when it does occur it differs from both infantile and adult-type polycystic disease. TS should be considered in the differential diagnosis of renal enlargement, haematuria and hypertension in childhood.

Child, Preschool↗
PubMed1983

[Was it necessary to treat acute carotid thromboses surgically? 1962-1973: long-term results].

A 13 years study of 22 patients with surgical treatment of acute occlusion of the internal carotid artery is reported. Mortality rate was 22% (5 patients). 35% had a complete recovery of the stroke without any sequelae. 6 were better after intervention, 3 worsened. Long term mortality is 10 patients with 2 strokes and 4 myocardial infarction. No significant difference can be observed on life table of the survivors with reference to recent medical series, 60% at five years, 36% at ten years, 28% 13 at years. A review of 30 studies of the literature (1,046 cases of acute stroke or transient ischemic attacks) shows a 17% global mortality, with 50% of good results. Mortality of surgical treatment of acute carotid occlusion is lower in recent papers (inferior 10%). This progression seems to be related to the selection of the indications of surgery in stroke (shorter delay, early diagnosis with non-invasive procedures, post-operative management). The conclusion is that a surgical therapy of acute thrombosis of the internal carotid artery cannot be systemically rejected.

Acute Disease↗
PubMed1980

Carotenoid transformations underlying the blue absorbance change in flashed leaves during the induction of oxygen evolution.

The blue absorbance change occurring in flashed bean (Phaseolus vulgaris L.) leaves when exposed to continuous light (first observed by Strasser; Strasser, R.J. (1973) Arch. Int. Physiol. Biochem. 81, 935--955) is caused by the conversion of the following xanthophylls: violaxanthine leads to antheraxanthine leads to zeaxanthine. This conclusion is derived from the simultaneous occurrence of both reactions: (a) In flashed leaves, blue absorbance change and xanthophyll conversion take place under strong (2 mW . cm-2) but not under weak (0.02 mW . cm-2) white light. (b) In chloroplasts isolated from flashed leaves, the blue absorbance change occurs in the dark under conditions that also induce the xanthophyll conversion. (c) Blue absorbance change and xanthophyll conversion are both inhibited by dithiothreitol. In addition, the light-induced blue absorbance change is reversed in the dark if aerobic conditions are maintained, i.e. under conditions that in normal leaves favor the reversal of the above reaction sequence. The significance of the xanthophyll conversion is discussed in relation to other phenomena occurring in flashed leaves after exposure to continuous illumination.

Ascorbic Acid↗
PubMed1978

[Prolonged fever revealing acquired toxoplasmosis in an adult].

Two cases of acquired toxoplasmosis are reported in 16 and 44 year old patients; prolonged fever was the dominating sign in both cases. It follows from these observations that toxoplasmosis has to be systematically considered as a possible etiology of prolonged fever of undetermined origin.

Adolescent↗
PubMed1977

[Hemorrhage complications of acute pancreatitis (author's transl)].

The authors report 11 cases of hemorrhage due to vascular ulcerations arising early or late in the course of acute pancreatitis. The seriousness of these hemorrhages, the difficulties of their therapy are pointed out. In all cases, bleeding should be controlled by surgery. Therefore, attention is drawn to the need for prompt laparotomy in all the shocked patients who failed to respond to conservative measures, for in such cases, a fatal outcome may rapidly occur. The respective advantages and inconveniences of the 2 main surgical treatments, ligation of bleeding vessels or pancreatectomy removing the source of bleeding, are discussed, basing on the presently reported cases and the data of the literature.

Acute Disease↗