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Biomedical subjects

F Louis

Publications and source records attributed to F Louis.

At least 19 recordsLinked to original sources
PubMed2006

Transdermal buprenorphine in pain management--experiences from clinical practice: Five case studies.

Buprenorphine is a semi-synthetic opioid derived from thebaine. The transdermal formulation of buprenorphine has been available in Belgium for 3 years, during which time the Pain Clinic of the St Elisabeth of Verviers Hospital has gained experience in the use of transdermal buprenorphine for the treatment of moderate-to-severe pain. This paper presents four cases of chronic, non-malignant pain, and one case of chronic cancer pain. By starting patients on low doses and slowly titrating upwards, transdermal buprenorphine matrix patches provided effective analgesia and were well tolerated. Low doses of transdermal buprenorphine were created by cutting the smallest available matrix patch (35 mug/h) into halves or quarters. The initial dose was then gradually titrated upwards to the dose needed for optimum pain relief by the patients. No problems were encountered in switching patients from prior analgesic therapy with other opioids to transdermal buprenorphine.

Administration, Cutaneous↗
PubMed2002

[Bronchial obstruction and the ideopathic hyper-eosinophilic syndrome].

The idiopathic hyper-eosinophilic syndrome is defined as a peripheral blood eosinophilia greater than 1.5 x 10(9)/litre present for at least 6 months and associated with visceral involvement. It may only be accepted after carefully excluding the other common or rare causes of hyper-eosinophilia and should remain a diagnosis of exclusion. The associated visceral lesions are multiple and non-specific. Among these neurological, digestive, dermatological and cardiac manifestations are the most frequently described. Whereas pleuro-pulmonary involvement is also common, asthma is rarely reported. We report a case of ideopathic hyper-eosinophilic syndrome presenting as asthma. This was secondary to eosinophilic infiltration of the bronchial mucosa as demonstrated by cytological examination of induced sputum.

Adult↗
PubMed2001

[Post-traumatic endocrine deficits : analysis of a series of 93 severe traumatic brain injuries].

OBJECTIVE: The aim of the study is to measure the incidence in severe traumatic brain injury of endocrine deficits with special consideration for hypotestosteronemia in male patients. PATIENTS AND METHODS: Retrospective analysis of a series of 115 TBIs consecutively admitted to our brain injury unit. Endocrine screening is routinely performed at admission and includes radioimmunological assays for T3, T4, TSH, testosterone or oestradiol and progesterone, FSH, LH and cortisol. Twenty-two records were incomplete and excluded from further analysis. The analysis relies on 93 records among which those of 75 males. RESULTS: One partial hypothyroidism of pituitary origin (low T3, T4 and TSH and no raise of TSH after stimulation by TRH) and one posthypophyseal deficit were found. The incidence of hypotestosteronemia is 28%. All are of central origin (low testosterone and low or normal LH). In one case the hypothalamic origin is demonstrated by the considerable increase of LH after injection of GnRH. We found no correlation between the occurrence of endocrine deficit and either the Glasgow Coma Scale or the existence of basal skull fracture. DISCUSSION - CONCLUSION: These results show that endocrine deficits are not exceptional in TBIs and that isolated hypotestosteronemia is frequent. These deficits are not necessarily all of functional origin, but further studies including longitudinal follow up are required to conclude on this point. Further studies addressing the opportunity of substitution in some patients should also be conducted.

Adult↗
PubMed1999

Reversion of the differentiated phenotype and maturation block in Sertoli cells in pathological human testis.

To study the relationship between abnormal Sertoli cell differentiation and spermatogenic impairment, we examined the expression of Sertoli cell markers normally lost at puberty, cytokeratin 18 (CK18), anti-Müllerian hormone (AMH) and M2A antigen, in three children (aged 1-2 years), 50 adults (aged 19-45 years) with obstructive or non-obstructive azoospermia or oligozoospermia, and six patients (aged 1-18 years) with 5 alpha-reductase deficiency. There was CK18 and/or AMH expression, but never M2A antigen expression, associated with spermatogonial arrest or Sertoli cell-only (SCO) syndrome in infertile men. Loss of M2A antigen suggests the transition of Sertoli cells to an adult phenotype, while CK18 and/or AMH expression may be a manifestation of de-differentiation of Sertoli cells. In 5 alpha-reductase deficiency, there was a sequential loss of CK18, M2A antigen and AMH around puberty, associated with partial spermatogenesis. The persistence of immature Sertoli cells expressing M2A antigen was associated with prepubertal seminiferous cords and SCO syndrome. Therefore, 5 alpha-reductase deficiency may prevent the maturation of Sertoli cells, resulting in impairment of spermatogenesis, and loss of M2A antigen expression coincides with a critical step in the Sertoli cell maturation. High follicle stimulating hormone concentrations due to failure of normal Sertoli cell differentiation indicate a normal development pattern of the hypothalamic-pituitary-gonadal axis.

Adolescent↗
PubMed1998

Receptors for anti-müllerian hormone on Leydig cells are responsible for its effects on steroidogenesis and cell differentiation.

Strong overexpression of anti-Müllerian hormone (AMH) in transgenic mice leads to incomplete fetal virilization and decreased serum testosterone in the adult. Conversely, AMH-deficient mice exhibit Leydig cell hyperplasia. To probe the mechanism of action of AMH on Leydig cell steroidogenesis, we have studied the expression of mRNA for steroidogenic proteins in vivo and in vitro and performed a morphometric analysis of testicular tissue in mice overexpressing the hormone. We show that overexpression of AMH in male transgenic mice blocks the differentiation of Leydig cell precursors. Expression of steroidogenic protein mRNAs, mainly cytochrome P450 17 alpha-hydroxylase/C17-20 lyase (P450c17), is decreased in transgenic mice overexpressing AMH and in AMH-treated purified Leydig cells. In contrast, transgenic mice in whom the AMH locus has been disrupted show increase expression of P450c17. In vitro, but not in vivo, AMH also decreases the expression of the luteinizing hormone receptor. The effect of AMH is explained by the presence of its receptor on Leydig cells. Our results provide insight into the action of AMH as a negative modulator of Leydig cell differentiation and function.

Animals↗
PubMed1996

Immunohistochemical detection of immature Sertoli cell markers in testicular tissue of infertile adult men: a preliminary study.

Testicular biopsy specimens from oligozoospermic infertile patients are characterized by different types of spermatogenic impairment in adjacent seminiferous tubules, a phenomenon called mixed atrophy. In order to evaluate possible involvement of the state of Sertoli cell differentiation, the distribution pattern of anti-Müllerian hormone (AMH), vimentin and cytokeratin intermediate filament proteins was investigated by means of immunohistochemistry. AMH immunoactivity occurs in Sertoli cells of the normal postnatal prepubertal testis, but it is absent in the adult testis with normal spermatogenesis. In the case of mixed atrophy, AMH immunoactivity was found in Sertoli cells of tubules showing spermatogenic arrest at the level of spermatogonia and in tubules showing Sertoli-cell-only (SCO) syndrome. Vimentin was expressed regularly in Sertoli cells independent of spermatogenic impairment or the state of Sertoli cell differentiation. Cytokeratin immunoactivity occurs in Sertoli cells of the normal postnatal prepubertal testis. Furthermore, cytokeratin expression was found in Sertoli cells of tubules showing spermatogenic arrest at the level of spermatogonia and in some SCO tubules. Co-expression of AMH and cytokeratin suggests that spermatogenic impairment such as spermatogenic arrest and SCO syndrome in human seminiferous tubules is associated with a population of Sertoli cells showing a prepubertal stage of development. The different pattern of AMH and cytokeratin expression in SCO tubules indicates that Sertoli cells in SCO syndrome show a mosaic pattern of differentiation.

Adult↗
PubMed1996

Testicular dysgenesis does not affect expression of anti-müllerian hormone by Sertoli cells in premeiotic seminiferous tubules.

Anti-Müllerian hormone (AMH) immunoreactivity was studied on paraffin sections obtained from archival testicular biopsies of 29 children with intersex disorders and of 22 controls. Strong AMH immunoreactivity was observed in Sertoli cell cytoplasm from 8 fetal weeks until puberty. During pubertal maturation, in both normal and intersex patients, AMH expression was present in premeiotic seminiferous tubules, but was no longer detected in neighboring tubules with meiotic development. AMH immunostaining was abolished in the testis of one patient with persistent Müllerian ducts due to a mutation of the AMH gene, but was conserved in the testes of two patients with mutations of the AMH receptor gene. Testicular dysgenesis usually results in sexual ambiguity, with low testosterone and AMH serum levels and persistence of Müllerian derivatives. AMH immunoreactivity was conserved in premeiotic seminiferous tubules of dysgenetic testes, and also in sex-cord cells of a gonadoblastoma. In patients with asymmetric gonadal differentiation, the streak gonad was AMH-negative. In conclusion, secretion of AMH is a constitutive feature of the immature Sertoli cell and its expression is altered only by mutations of the AMH gene, but not by gonadal dysgenesis. The degree of regression of Müllerian ducts and serum AMH levels reflect the number, not the functional value, of Sertoli cells present in the immature testis.

Adolescent↗
PubMed1995

Ontogeny of reproductive abnormalities induced by deregulation of anti-müllerian hormone expression in transgenic mice.

Anti-müllerian hormone, normally responsible for the regression of müllerian ducts in male fetuses, induces stunting, germ cell loss, and seminiferous tubule formation in ovaries of bovine freemartin fetuses and of transgenic mice, which express the human anti müllerian hormone gene under the control of the metallothionein promoter. Because the latter have been studied only after birth, we undertook a detailed chronological study of their reproductive organs. Müllerian ducts of transgenic female fetuses regressed at the same time as those of normal or transgenic males. Maximal reduction of germ cell number occurred between 16 days postcoitus and birth, when most transgenic oocytes were still in the leptotene stage of the meiotic prophase, whereas normal oocytes had already reached the pachytene phase. Interference with progression of the meiotic prophase and germ cell loss in the fetal ovary are probably responsible for subsequent ovarian regression and retardation of follicle growth. Seminiferous tubule formation was not detectable prior to birth and occurred only rarely in postnatal ovaries. Aromatase activity of fetal transgenic ovaries was decreased, as well as serum concentration of testosterone in adult transgenic males, suggesting that high levels of anti-müllerian hormone may impair Leydig cell steroidogenesis.

Animals↗
PubMed1994

Bronchopulmonary sequestration: prenatal diagnosis with clinicopathologic correlation.

A patient was referred at 21 weeks' gestation for evaluation of an echogenic mass in the fetal right chest. Color-doppler sonography facilitated the diagnosis of a bronchopulmonary sequestration. Clinicopathologic correlation was possible after termination at 2.3 weeks' gestation. Pathologic examination confirmed the prenatal diagnosis and demonstrated the systemic vascular supply seen on color-doppler sonography. Color doppler is a useful adjunct in the sonographic evaluation of the fetus with an echogenic chest mass.

Adult↗
PubMed1990

Maternal awareness and neonatal outcome after ketamine induction of anaesthesia for Caesarean section.

Ketamine was used as the sole anaesthetic during the induction-to-delivery interval in 20 full-term patients undergoing elective Caesarean section. The intravenous administration of ketamine 1.5 mg.kg-1 was followed by succinylcholine 1.5 mg.kg-1 and tracheal intubation. The mother's lungs were then ventilated using 100 per cent oxygen until the baby was delivered. Intraoperative maternal awareness was assessed by the isolated forearm technique. The Apgar scores of the newborn at one and five minutes, as well as their umbilical vein blood gases were also evaluated and correlated with the induction-to-delivery (I-D) and the uterine incision-to-delivery (U-D) intervals. In 13 patients (Group A) the I-D interval was less than 10 min and U-D interval less than 90 sec, while in seven (Group B) the I-D interval was greater than or equal to 10 min and the U-D interval greater than or equal to 90 sec. The isolated arm test was negative in all patients having an I-D interval less than 10 min, and was positive in three patients when the I-D interval exceeded ten minutes. The newborns of group A showed higher Apgar scores at one minute, as well as higher umbilical vein PO2 than was achieved in Group B. It was concluded that the technique used was not associated with maternal awareness or neonatal depression, provided that the I-D interval was less than 10 min and the U-D interval was less than 90 sec.

Adult↗
PubMed1989

Pulmonary hypoplasia and osteogenesis imperfecta type II with defective synthesis of alpha I(1) procollagen.

Perinatal lethal osteogenesis imperfecta (OI type II), a heritable disorder of connective tissue occurs approximately once in 60,000 live births. Phenotypic characteristics include defective cranial ossification and severe skeletal deformity due to intrauterine rib and long bone fractures. Lethal OI may be associated with intracranial hemorrhage or severe respiratory insufficiency. Pulmonary hypoplasia has been previously observed in OI type II, but has not been defined clinically. The infant described herein was born with OI type II and pulmonary hypoplasia. Pathological examination of airway branching patterns indicated that lung development had progressed to only the 10 week stage with immature acinar development. Investigation type I collagen synthesis by cultured dermal fibroblasts revealed the presence of electrophoretically abnormal alpha 1(I) polypeptides. These findings suggest that biochemically regulated processes, as well as mechanical factors, may impeded pulmonary development in similar cases of OI type II.

Culture Techniques↗
PubMed1989

Awareness following different techniques of general anaesthesia for caesarean section.

Using the isolated arm technique, the frequency of awareness was evaluated in 50 full-term patients undergoing elective Caesarean section under general anaesthesia. In 20 patients, anaesthesia was induced with thiopentone 4 mg kg-1, and in the other 30 patients, induction was with ketamine 1.5 mg kg-1. Following suxamethonium 1.5 mg kg-1 and tracheal intubation, anaesthesia was supplemented during the induction-delivery period in the thiopentone group with 50% nitrous oxide and 0.5% halothane in oxygen in 10 patients, and with 1% halothane in 100% oxygen in the other 10 patients. In the ketamine group, the patients underwent ventilation with 50% nitrous oxide and 0.5% halothane in oxygen in 10 patients, with 1% halothane in 100% in 10 patients, and with 100% oxygen only in the last 10 patients. Awareness was significantly greater after induction with thiopentone (14/20) than after ketamine (4/30). There were no significant differences in Apgar scores or umbilical vein blood-gas values in the newborns.

Anesthesia, General↗
PubMed1989

[Development of nocturnal desaturation in 35 patients with chronic obstructive bronchopneumopathy (COBP). Relation to functional and hemodynamic data].

35 patients with chronic airflow obstruction in a stable state were studied using nocturnal oximetry on two occasions with an interval of 25 +/- 10 months between them. First we studied the predicted value for the pulmonary function factors during the day to compare with nocturnal desaturation. On the second occasion we compared the progress of the desaturation indices and the outcome of the functional and hemodynamic data. The PaO2, the PaCO2 and the VEMS/CV ratio (FEV1/VC) were the only elements during waking which correlated with the degree of nocturnal desaturation. In spite of this correlation and the fact that the confidence intervals were large, the predictable element of these daytime measurements remained weak in daily practice. The progress between the two oximetric measurements of the PaO2 and the PaCO2 as well as the fall in the FEV1 (VEMS) was strongly linked to the evolution of desaturation during sleep. This progressive aspect shows the value of nocturnal oximetry in patients who are evolving towards alveolar hypoventilation. Finally, the outcome of pulmonary arterial pressure appears predictable as a result of the progress of nocturnal desaturation.

Aged↗
PubMed1989

Epidural meperidine for control of autonomic hyperreflexia in a quadriplegic undergoing cystoscopy.

Epidural meperidine was used to control autonomic hyperreflexia (AH) during cystoscopy and transuretheral sphincterotomy, in a quadriplegic patient who had chronic spinal cord transection at C6 level. Meperidine 100 mg diluted in 10 ml saline was injected in the epidural space at L3-L4 level. Within 10 minutes and throughout the surgical procedure, the blood pressure stabilized at 125/70-140/80 mmHg. Epidural meperidine produces selective blockade of the spinal opiate receptors and hence may block the nociceptive reflexes below the level of cord transection and prevent AH.

Autonomic Nervous System Diseases↗
PubMed1988

A method for determining simultaneously the dose and the elapsed time since irradiation using TLDs.

Information about the time that has elapsed since an external radiation exposure is useful in order to determine the time of occurrence of an abnormal exposure in personal and accidental dosimetry is presented. This information can be obtained from certain irradiated thermoluminescent dosimeters. A computational method based on decay rates of thermoluminescence glow peaks has been used to estimate a range of suitable values of trap lifetimes of low temperature glow peaks. This provides a basis for the selection of an appropriate thermoluminescent material to assess not only the absorbed dose from a radiation exposure, but also the elapsed time. Experimental studies have been used to obtain additional information on decay rates as a function of energy, temperature and absorbed dose.

Accidents↗