Biomedical subjects
Publications and source records attributed to A Lacroix.
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Retinoic acid (RA), an important regulator of cell differentiation, is biosynthesized from retinol via retinal by a two-step oxidation process. We previously reported the purification and partial amino acid (aa) sequence of a rat kidney aldehyde dehydrogenase (ALDH) isozyme that catalyzed the oxidation of 9-cis and all-trans retinal to corresponding RA with high efficiency [Labrecque et al. Biochem. J. 305 (1995) 681-684]. A rat kidney cDNA library was screened using a 291-bp PCR product generated from total kidney RNA using a pair of oligodeoxyribonucleotide primers matched with the aa sequence. The full-length rat kidney ALDH cDNA contains a 2315-bp (501 aa) open reading frame (ORF). The aa sequence of rat kidney ALDH is 89, 96 and 87% identical to that of the rat cytosolic ALDH, the mouse cytosolic ALDH and human cytosolic ALDH, respectively. Northern blot and RT-PCR-mediated analysis demonstrated that rat kidney ALDH is strongly expressed in kidney, lung, testis, intestine, stomach and trachea, but weakly in the liver.
The pleiotropic effects of retinoids are mediated by two families of nuclear receptors: RAR (retinoic acid receptors) and RXR (retinoid X receptors). 9-cis-Retinoic acid is a specific ligand for RXR receptors, whereas either 9-cis- or all-trans-retinoic acid activates the RAR receptor family. The existence of RXRs suggests a new role for isomerization in the biology of retinoic acid. We report here the identification of an aldehyde dehydrogenase in the rat kidney that catalysed the oxidation of 9-cis- and all-trans-retinal to corresponding retinoic acids with high efficiency, 9-cis-retinal being 2-fold more active than all-trans-retinal. Based on several criteria, such as amino acid sequence, pH optimum, and inhibition by chloral hydrate, this enzyme was found to be a novel isoenzyme of aldehyde dehydrogenase. 9-cis-Retinol, the precursor for the biosynthesis of 9-cis-retinal was identified in the rat kidney. The occurrence of endogenous 9-cis-retinol and the existence of specific dehydrogenase which participates in the catalysis of 9-cis-retinal suggest that all-trans-retinoi(d) isomerization to 9-cis-retinoi(d) occurs at the retinol level, analogous to all-trans-retinol isomerization to 11-cis-retinol in the visual cycle.
Experiences and views of patients are presented concerning psychological, professional, family life, cognitive and financial aspects of the costs of several chronic diseases: arterial hypertension, autonomous dialysis, back pain, bronchial asthma, chronic obstructive pulmonary disease, colostomy, diabetes mellitus, epilepsy, laryngectomy, Parkinson's disease. The posters expressed what patients would really like to tell their doctors.
A medical congress brings together those doctors who are interested in the proposed theme of that particular congress. Within the congress 'Patient Education 2000' an unusual aspect was the presentation, in the form of posters, of the requirements of patients suffering from one of the diseases or conditions covered by the congress. On the one hand, these posters showed the impact of the illness; on the psychological aspect, within the family, within the professional and social lives as well as the financial aspect. On the other hand, the posters showed what the patients really wanted to say to the health care team. In this paper we present a synthesis illustrating certain significant examples.
We examined pathology records to determine the accuracy of reports of breast cancer among 125 first-degree relatives by 414 breast cancer cases and 429 population-based controls. Cases who reported only one affected relative tended to overreport the occurrence of breast cancer to a slightly larger extent (4%) than controls (3%). One-third of reports by cases with at least two affected relatives were erroneous, compared with none in the control group. Both cases and controls committed absolute errors of approximately 2 years when reporting the age at diagnosis of relatives. These results indicate that some recall bias is introduced when self-reports of breast cancer occurrence in first-degree relatives are used in case-control studies.
This study evaluates how diabetic patients understand the meaning of 8 medical terms related to retinopathy. Divided into 4 groups, 142 persons, were questioned at the end of a consultation with their ophthalmologist. Groups 1, 2 and 3 were diabetic patients; 1, without retinopathy, 2, with pre-proliferative retinopathy, 3, treated with laser. Group 4 included non-diabetic controls. The results show only one third of correct answers. Results illustrate a big diversity in understanding according to the terms which, nevertheless, were currently used by the doctors during their ophthalmological consultation. Sociodemographic variables did not have any effect on the understanding of terms dealing with diabetic retinopathy. We only observed a positive correlation between knowledge of patients and laser treatment. On analysing the contents of the patients' definitions, we discovered an important variety of different conceptions of the retinal disease. By not verifying patients' understanding of medical terms, both the physician and patient have no doubts as to their competence to understand them. This failure could have severe consequences not only at the level of prevention but also concerning the early treatment of diabetic retinopathy.
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Temporal changes in plasma levels of luteinizing hormone (LH), testosterone, estradiol, and progesterone were measured throughout molt and the onset of reproduction in free-living male and female King penguins (Aptenodytes patagonicus) at Crozet Island (46 degrees S, 51 degrees E). In both sexes, LH concentrations began to rise as soon as molting ended, before the departure for refeeding at sea, suggesting that the beginning of reproductive activity is not associated with refeeding and/or courtship behavior. LH remained at high values throughout courtship and decreased to lower levels during incubation. Gonadotrophin secretion covaried with sustained plasma testosterone levels in males and increased estradiol and progesterone levels (peaking at copulation) in females.
Adrenalectomy is usually performed via transabdominal or posterior approaches. Unfortunately, both approaches are associated with painful postoperative syndromes. Recently, laparoscopic surgery was applied to organ removal. During a period of 12 months, we performed a series of successful laparoscopic adrenalectomies (10 of the right and 11 of the left gland). The pathologies were medullary cyst (1), angiomyolipoma (1), DHEAS hyperplasia (1), primary aldosteronism (2), Cushing's adenoma (3), pheochromocytoma (4), Cushing's syndrome (4), and nonfunctional adenoma (5). A flank approach was taken with four 11-mm trocars. Electrocautery and blunt forceps were used for dissection. The vessels were secured with medium-large titanium clips, and the adrenal was removed in a sterile plastic bag. The average operating time was 2.3 h, and median postoperative stay was 4 days. Two patients required blood transfusion of 2 units postoperatively. We believe this technique is adequate for the surgical removal of adrenal tissue, resulting in less postoperative pain and in rapid recovery. It may also change the surgical management of asymptomatic adrenal lesions.
The relationship between the corpus luteum and the uterus in terms of the secretion of oxytocin and PGF2 alpha was investigated in free-living and captive roe deer Capreolus capreolus. During the breeding season the corpus luteum contained oxytocin and oxytocin-neurophysin mRNA, and secreted oxytocin in response to administration of the PGF2 alpha analogue cloprostenol. The oxytocin receptor was present in the uterus during the bleeding season and during delayed implantation; however, in contrast to the situation observed in other ruminants in which it has been studied, administered oxytocin did not stimulate uterine secretion of PGF2 alpha. Trophoblast interferon was undetectable at any stage of conceptus development. The absence of the mechanism underlying episodic uterine secretion of PGF2 alpha during luteolysis, which may account for the monoestry of roe deer, is consistent with the previously observed luteolytic effect of the PGF2 alpha analogue.
Blood samples and testes were collected from long-finned pilot whales (Globicephala melas) off the Faroe Islands at irregular intervals over a period of 3 years (July 1986-December 1989). Changes in testis mass (n = 674) and plasma testosterone concentrations (n = 214), measured by radioimmunoassay, were examined with respect to age, bodylength and bodymass of the animals. Corresponding to a rapid testicular growth (from 0.25 kg up to 1.9 kg), puberty occurred in male pilot whales of 4.6-5.7 m in bodylength, 1.2-1.9 tonnes in bodymass and 11-22 years of age. Changes in plasma testosterone concentrations confirmed this result, with very low values (< 2 ng ml-1) in immature animals (testis mass < 0.2 kg), followed by a sharp increase (from 2 to 29 ng ml-1) during the pubertal period, and the maintenance of high concentrations with large variability (> 1.5 ng ml-1 to 14 ng ml-1) in mature males. Testosterone concentrations were significantly correlated with testis mass (P < 0.001), but not with bodylength or age, and very large individual variations were observed in mature males. The average age, length and mass at the attainment of sexual maturity were estimated at 16.99 +/- 0.30 years, 5.162 +/- 0.013 m and 1.403 +/- 0.005 tonnes, respectively.
Multiple endocrine neoplasia type 2B (MEN 2B) is characterized by medullary thyroid carcinoma, pheochromocytomas, mucosal neuromas, ganglioneuromas, and skeletal and ophthalmic abnormalities. It is observed as both inherited and sporadic disease, with an estimated 50% of cases arising de novo. A single point mutation in the catalytic core region of the receptor tyrosine kinase, RET, has been observed in germ-line DNA of MEN 2B patients. We have analyzed 25 cases of de novo disease in order to determine the parental origin of the mutated RET allele. In all cases the new mutation was of paternal origin. We observe a distortion of the sex ratio in both de novo MEN 2B patients and the affected offspring of MEN 2B transmitting males. These results suggests a differential susceptibility of RET to mutation in paternally and maternally derived DNA and a possible role for imprinting of RET during development.
Occurrence of a chronic disease means to the patient the loss of his accustomed state of health. That is what a newly diagnosed diabetic patient experiences, when he is confronted with the necessity for a perpetual treatment in order to keep his blood sugar levels as normal as possible. Furthermore, this disease may induce severe secondary complications because adjustment is difficult. Ability and will-power to care for himself depend on the degree of acceptance of the disease by the patient himself. This implicates a period of sorrow, characteristic phases of which have been identified and described by several authors. The relation between physician and patient plays an important role in this process. The physician should not only recognize the emotional reactions of his patient but also respond adequately.
The compliance of diabetic patients is very poor. In addition to the knowledge of the various stages of acceptance of the disease as described by A. Lacroix in this journal, it is necessary to learn more about the patient's personality. In this article, four different personalities are proposed using the test "Persona" (Polymanagement SA, Geneva) in order to have the correct choice of therapy, corresponding to the personality. We hope that in the long term, by using this test, therapeutic compliance for the diabetic patients will be improved.
1. The annual profiles of plasma thyroid-stimulating hormone (TSH), thyroxine (T4), luteinizing hormone (LH) and testosterone (T) concentrations in control and ganglionectomized (SCGx) dormice were analyzed to determine whether the pineal gland affects thyroid-gonadal interactions in response to the seasonal influence of environmental factors. 2. Dormice ganglionectomized in September, around the time of prehibernation when hormonal activity is minimal had significantly disturbed annual cycles of plasma T4, LH and T, while the TSH cycle was unchanged. 3. SCGx performed after breeding season (June), only affected the T4 variations, while the T and LH titers were similar to those of controls. 4. We conclude that the annual cycles of T4 and testosterone are controlled by the sympathetic nervous system via the superior cervical ganglion which innervates both the pineal gland and the thyroid. 5. During the start of seasonal gonadal activity, which is strongly dependent on thyroid-gonadal interactions, the inhibitory action of the pineal gland on the neuroendocrine thyroid axis, or most probably a direct inhibition of the thyroid by the sympathetic innervation from SCG, might influence the timing of the reproduction cycle. 6. The lack of thyroid-gonadal interaction at the end of the breeding season suggests that the thyroid disturbance caused by ganglionectomy in June does not cause gonadal perturbation at this time.
In a case-control study of cancer of the colon it was found that 96 out of 332 (29%) cases had a positive family history of cancer of the colon (2 cases and more) as compared with 19 out of 473 (4%) controls. 3 colon cancer cases reported that 6 of their respective relatives were also affected with the same cancer. We were able to do a complete follow-up study of one family where 7 out of 12 sibling (P < 0.05) had confirmed pathological diagnoses of cancer of the colon. The mean age at diagnosis among these familial colon cancer cases was 64 years (60 years for females and 73 years for males) and all tumours were located in the caecum or right colon (a common characteristic of colon cancer in this family). There was no history of familial adenomatous polyposis in this family. It is unlikely that the significantly high proportion of familial colon cancer found could be due to chance. This suggests that both environmental and genetic factors play an important role in the aetiology of colon cancer.
Identical measures of social ties obtained from three community-based cohorts aged 65 and over from East Boston, MA; New Haven, CT; and two rural counties in Iowa permit the first direct cross-community comparison of the hypothesis that social isolation increases 5-year mortality risks (1982 to 1987) for older men and women. In sex-specific proportional hazards analyses, social ties were significantly and inversely related to mortality independently of age in all three cohorts (e.g., relative hazard (RH) = 1.97 to 3.06 for men and women, comparing those with no ties to those with four types of ties). After controlling for age, pack-years of smoking, body mass, chronic conditions, angina, and physical and cognitive disability, social ties remain significant predictors of mortality risk for the men and women in New Haven (RH = 2.4 and 1.8) and for women in Iowa (RH = 1.9). For the men in Iowa (RH = 1.4) and the men and women in East Boston (RH = 1.0 and 1.3), the associations are weaker and nonsignificant.