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Biomedical subjects

O Morin

Publications and source records attributed to O Morin.

At least 37 records · Page 2Linked to original sources
PubMed1996

Changes in sleeping and basal energy expenditure and substrate oxidation induced by short term thyroxin administration in man.

The present study was designed to explore the thermogenic effect of thyroid hormone administration and the resulting changes in nitrogen homeostasis. Normal male volunteers (n = 7) received thyroxin during 6 weeks. The first 3-week period served to suppress endogenous thyroid secretion (180 micrograms T4/day). This dose was doubled for the next 3 weeks. Sleeping energy expenditure (respiratory chamber) and BMR (hood) were measured by indirect calorimetry, under standardized conditions. Sleeping heart rate was continuously recorded and urine was collected during this 12-hour period to assess nitrogen excretion. The changes in energy expenditure, heart rate and nitrogen balance were then related to the excess thyroxin administered. After 3 weeks of treatment, serum TSH level fell to 0.15 mU/L, indicating an almost complete inhibition of the pituitary-thyroid axis. During this phase of treatment there was an increase in sleeping EE and sleeping heart rate, which increased further by doubling the T4 dose (delta EE: +8.5 +/- 2.3%, delta heart rate +16.1 +/- 2.2%). The T4 dose, which is currently used as a substitutive dose, lead to a borderline hyperthyroid state, with an increase in EE and heart rate. Exogenous T4 administration provoked a significant increase in urinary nitrogen excretion averaging 40%. It is concluded that T4 provokes an important stimulation of EE, which is mostly mediated by an excess protein oxidation.

Adult↗
PubMed1996

Interleukin-1 beta inhibits rat thyroid cell function in vivo and in vitro by an NO-independent mechanism and induces hypothyroidism and accelerated thyroiditis in diabetes-prone BB rats.

Interleukin-1 beta has been implicated as a pathogenic factor in the development of autoimmune thyroiditis. When given for 5 days to normal non-diabetes-prone Wistar Kyoto rats, it decreased plasma concentrations of total tri-iodothyronine and thyroxine and increased plasma TSH. These effects were not prevented by co-injection of nitroarginine methyl ester or aminoguanidine, inhibitors of NO synthases. Exposure to interleukin-1 beta dose-dependently reduced iodine uptake in FRTL-5 cells, but had no effect on thyroglobulin secretion. Nitrite was not detected in the FRTL-5 cell culture media after exposure to interleukin-1 beta. However, reverse transcription PCR analysis of mRNA isolated from interleukin-1 beta-exposed FRTL-5 cells revealed a transitory expression of the inducible NO synthase, which was markedly lower than inducible NO synthase induction in interleukin-1 beta-exposed isolated rat islets of Langerhans. Co-incubation with the NO synthase inhibitor NG-monomethylarginine did not ameliorate the effect of interleukin-1 beta on FRTL-5 cell iodine uptake. Furthermore, we demonstrate that daily injections of interleukin-1 beta for 13 weeks aggravated spontaneous thyroiditis and induced severe hypothyroidism in non-diabetic diabetes-prone BB rats. The data suggest that NO does not mediate interleukin-1 beta-induced inhibition of rat thyroid function in vivo or in vitro in FRTL-5 cells, and the induction of hypothyroidism by interleukin-1 beta in diabetes-prone BB rats is speculated to be due to exacerbation of recruitment and activation of intrathyroidal mononuclear cells.

Animals↗
PubMed1995

Long-lasting effects of Triac and thyroxine on the control of thyrotropin and hepatic deiodinase type I.

The purpose of this study was to investigate the relation between the serum levels of thyroid hormones and their biological effects. For this purpose, hypothyroid rats were studied after stopping treatment with a long-acting thyroid hormone, thyroxine (T4) and a short-acting one, triiodothyroacetic acid (Triac). Based on preliminary experiments with different doses of T4 and Triac, hypothyroid rats (N = 84) received over 6 days' injections of 10 nmol Triac or 2 nmol T4/100 g body wt per day. Biological effects of Triac and T4 were measured in the pituitary, liver and kidney up to 8 days after stopping treatment. With Triac, serum thyrotropin (TSH) levels were inhibited completely 6 h after injection, yet after 24 h they were 4.9 +/- 1.8 micrograms/l (hypothyroid 14.5 +/- 0.8 micrograms/l). The rapid changes in serum TSH levels were followed by a more gradual increase in serum TSH levels were followed by a more gradual increase in serum TSH, which was similar to that after T4 injection. Even 8 days after Triac treatment, serum TSH levels did not reach the hypothyroid control levels. Changes in beta-TSH mRNA levels also showed a prolonged inhibition after both treatments and a slow return to hypothyroid values, which was not complete 8 days after stopping treatment. A second parameter was hepatic 5'-deiodinase type I (5'D-I). The 6-day treatment with Triac had a markedly stronger effect on 5'D-I enzyme activity and mRNA levels than treatment with T4.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Invasive aspergillosis in intensive care].

Invasive pulmonary aspergilloses occur in patients with antineoplasic chemotherapy, mainly when associated with a prolonged neutropenia, in transplanted patients with continuous corticotherapy and less frequently in immunocompetent surgical patients. The clinical features are those of an acute infective pneumonia, not responding to antibiotherapy. Radiologic signs are often non specific. Diagnosis is obtained with bronchoalveolar lavage in which Aspergillus is found both at direct examination and in culture. Serological tests are of little interest for the diagnosis of invasive aspergillosis. Extrapulmonary locations such as sinusitis, cutaneous or brain abscesses occur in 20% of cases. The gold standard of treatment is intravenous amphotericin B which elicits an acute reaction often followed by a nephrotoxic effect which can be decreased by fluid loading with saline. Oral itraconazole administration can follow the initial treatment with amphotericin B. The mortality rate remains high and an early diagnosis and an appropriate treatment are essential.

Amphotericin B↗
PubMed1994

[Aspergillosis and malignant hemopathies].

Infections caused by fungi of the genus Aspergillus have become a major and dangerous problem in the modern treatments of blood diseases using cytotoxic drugs. Invasive pulmonary aspergillosis is the usual clinical manifestation of the disease. The clinical signs, not very suggestive, are those of an infective pneumonia and localized radiological forms are initially more frequent in most cases. The extra pulmonary forms are frequent: nose and sinus, skin, bone, digestive, central nervous system are principal localisations; but all organs may be affected by the processus of dissemination. The proximal tracheobronchial localisations may be seen by fibroscopy in 20% of cases, associated to invasive pulmonary aspergillosis. Diagnosis rests on pathological data, but in many cases the only possible examinations are broncho-alveolar lavage and bronchial brushing. The positive results are a major test of diagnosis.

Antineoplastic Agents↗
PubMed1993

[Invasive aspergillosis in surgical intensive care patients].

Aspergillosis is a rare event in intensive care patients. Three cases of invasive aspergillosis due to Aspergillus fumigatus were diagnosed in a surgical critical care unit. Risk factors for aspergillosis were found in two liver transplanted patients. One of them had a primitive cutaneous aspergillosis, and the other, treatment difficulties due to the unavailability of an injectable preparation of itraconazole, a new triazole antifungal agent efficient against Aspergillus species. The third case occurred in a patient who had had surgery for gastric carcinoma with liver metastasis. The mycological examination of the air and workbench in the patients' rooms disclosed between 2 and 13 CFU.mm-3 of different Aspergillus species. Plasma itraconazole concentrations were measured in one patient only. They were below the therapeutic range, probably because of intestinal disturbances. The oral administration of itraconazole capsules through gastro-intestinal feeding tubes results in a poor availability of the drug. Such a technique of administration should therefore be undertaken with larger doses than those commonly recommended. Moreover, itraconazole plasma concentrations should be monitored. The association with amphotericin B is recommended until normal intestinal absorption has been obtained.

Adult↗
PubMed1993

Comparison of the metabolic and endocrine effects of 3,5,3'-triiodothyroacetic acid and thyroxine.

To test the hypothesis that 3,5,3'-triiodothyroacetic acid (Triac) is more active as a TSH suppressor than on peripheral parameters of thyroid hormone action, the following parameters were studied: basal metabolic rate, sleeping energy expenditure (SEE), sex hormone-binding globulin, and cholesterol. In a double blind trial, 14 subjects received during 3 weeks (phase 1) 180 micrograms T4 or 1700 micrograms Triac daily, divided into 3 doses, to suppress thyroidal secretion. The dosage was doubled for the next 3 weeks (phase 2). Under T4 treatment, TSH reached 0.11 mU/L during phase 1 and less than 0.03 mU/L during phase 2. With Triac, a marked TSH inhibition occurred after 1 week (0.17 mU/L), followed by an escape during the following 2 weeks (0.63 mU/L). During phase 2, an almost complete TSH suppression was obtained (0.03 mU/L). Both Triac doses suppressed endogenous thyroid hormone secretion, as evidenced by T4 and rT3 levels. Both substances induced a 2-fold stimulation of sex hormone-binding globulin during phase 2. Serum cholesterol decreased similarly, without affecting the high/low density lipoprotein ratio. T4 increased SEE by 4.1% and 8.5% during phases 1 and 2. Triac failed to induce the expected peripheral metabolic responses of the thyroid hormones, as demonstrated by an unchanged SEE and basal metabolic rate. These results clearly show a preferential action of Triac on TSH suppression.

Basal Metabolism↗
PubMed1993

Effect of the antioxidant TK 12627 (Irganox) on monodeiodination and on the levels of messenger ribonucleic acid of 5'-deiodinase type I and spot 14.

Until now, most potent inhibitors of monodeiodination are iodinated, propylthiouracil being an exception. We report here studies on a new non-iodinated substance, triethylene glycol bis-3-(3-tert-butyl-4-hydroxy-5-methyl-phenyl) propionate (TK 12627 or Irganox), which is used as a very efficient antioxidant in the chemistry of plastics. The studies were performed with 23 hypothyroid rats that received Irganox in their daily food (8 mg.day-1 x (100 g body wt)-1) for 3 weeks. Thyroxine (T4) metabolism was studied by implanting minipumps delivering 2.3 nmol T4.day-1 x (100 g body wt)-1 for 1 week. On day 1 before sacrifice, another minipump containing [125I]-3,5,3'-triiodothyronine (T3, 2.6 microCi/day) and [131I]-3,3',5'-triiodothyronine (rT3, 2.1 microCi/day) was implanted. The results showed that with Irganox treatment serum T4 concentrations were higher (p < 0.05). Serum T3 concentrations markedly decreased (1.07 +/- 0.07 vs 0.65 +/- 0.04 nmol/l), accompanied by a decrease of free T3 concentrations (p < 0.001). Serum rT3 concentrations increased by 50% (p < 0.001). Serum thyrotropin levels were mostly unmeasurable. The plasma clearance rate decreased slightly for T4 (19%, p < 0.05) and remarkably for rT3 (46.7%, p < 0.001). The conversion rate of T4 to rT3 did not change. Deiodinase type I (5'D-I) activity decreased in both liver and kidney tissues by 54% and 52%, respectively, and correlated with T3 (r2 = 0.79 and 0.65, respectively). Brain deiodinase type III (5D-III) was unchanged and type II (5'D-II) was unmeasurable.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1989

[Invasive pulmonary aspergillosis].

Infections caused by fungi of the genus Aspergillus have become a major and dangerous problem in the modern treatments of blood diseases using cytotoxic drugs. Invasive pulmonary aspergillosis, generally caused by A. fumigans and A. flavius, is the usual clinical manifestation of the disease, but subacute forms have been described in patients with little immunodeficiency. The clinical signs, not very suggestive, are those of an infective pneumonia, and localized radiological forms are initially more frequent in most cases. Diagnosis rests on pathological data, but in many cases the only possible examinations are broncho-alveolar lavage and bronchial brushing which give both sensitive and specific results. Treatment is basically medical and consists of intravenous infusions of amphotericin B. The earlier the treatment the better the outcome which seems to be more favourable in patients with localized infection.

Amphotericin B↗
PubMed1986

Long-term maintenance of hepatocyte functional activity in co-culture: requirements for sinusoidal endothelial cells and dexamethasone.

Sinusoidal cells isolated from adult rat liver have been established in primary culture and in cell line. The presence of factor VIII R:Ag and peroxidatic/phagocytosis activities were the criteria used to distinguish in freshly isolated cells the endothelial cells from the Kupffer cells and suggested the endothelial origin of the cell line. Using a co-culture system, the effect of sinusoidal liver cells on hepatocyte functional activity was characterized. A plateau in which the state of differentiation was stabilized could be generated for co-cultured hepatocytes isolated from adult rat and a disappearance of the initial expression of alpha 1-fetoprotein (AFP) and the increase and/or maintenance of albumin secretion were measured with co-cultured hepatocytes isolated from suckling rat. The presence of dexamethasone was required for such beneficial effect. The hepatocyte-stabilizing activity was also produced by a pulmonary endothelial cell line.

Cell Communication↗
PubMed1986

[Osteoid osteoma of the floor of the acetabulum in children. Apropos of a case].

The authors report a case of osteoid osteoma of the acetabulum in a 5 year old child. It was resected after arthrotomy by an anterior approach. The upper end of the femur was deformed and this was related to impaired growth. After the operation, the pain subsided but the deformity was still noticeable two years later.

Acetabulum↗
PubMed1985

[Results of the surgical treatment of chronic external laxity of the ankle by resetting capsular ligamentous tension].

The authors review 12 patients operated for tibio-tarsal instability and summarize the effects of ligamentous sections of the capsular-ligamentous plane of the lateral part of the ankle and the importance of the anterior peroneotalar fascia. In cases of tibio-tarsal instability, the authors propose a lateral ligamentous re-tension plasty with trans-osseous reinsertion and they analyse the results of this operation in a series of 13 operated ankles which were followed clinically and radiologically. The essential criterion of evaluation was a return to the same level of sports activity (7 very good results, 3 good results, 2 moderate results and one failure). The overall favourable results suggest that this technique can be indicated in a number of rare cases: sportsmen with significant disability after failure of treatment by proprioceptive re-education. In conclusion, the authors stress the value of preventative treatment of sprained ankles, which should prevent the development of instability.

Adolescent↗
PubMed1984

Heterogeneity of endothelial cells of adult rat liver as resolved by sedimentation velocity and flow cytometry.

Sinusoidal cells isolated from adult rat liver were fractionated by velocity sedimentation at 1 X g ( primarily on the basis of size) and the various cell fractions were further analysed by flow cytometry on the basis of forward and perpendicular light scattering and autofluorescence. Cell volume was also measured electronically using a Coulter counter. At least four enriched cell populations were resolved after velocity sedimentation. They corresponded to cells having a modal diameter of 6.5, 7.5, 9, and 11 microns, respectively. Transmission electron microscopy (TEM) analysis of the various cell populations revealed that the 7.5- and 9-microns cell fractions represented two distinct classes of endothelial cells while the 11-microns cells corresponded to Kupffer cells. The 6.5-microns cells were identified as lymphocytes. Fat-storing cells, identified by their autofluorescence and lipid content, were included in the Kupffer population. Further information about the nature of the two physically distinct endothelial cell populations was obtained by TEM. It demonstrated that the smaller endothelial cells possessed quantitatively and relatively less retracted sieve plates than the larger ones. This ultrastructural feature can be possibly correlated to a differential localization of the two classes of endothelial cells within the liver acinus.

Animals↗
PubMed1983

[Babesiasis, pediatric malaria: does confusion exist in Africa?].

The authors describe a case of febrile disease acquired by a nursling in Africa: was it induced by Pl. falciparum or by Babesia sp.? In spite of numerous microscopic and serological appraisals from veterinary and medical authorities, it is difficult to state definitively this subject, but it is more probably a babesiosis of canine or rodent origin.

Animals↗