Biomedical subjects
G Pattyn
Publications and source records attributed to G Pattyn.
Calbindin localization in African giant rat kidney (Cricetomys gambianus).
Cricetomys gambianus are rodents living in savanna and follow area. They can live with restricted drinking water eating fresh food. Therefore their kidney may have some adaptive mechanisms for ion/water homeostasis compared to usual laboratory rats. In this study we have looked for calbindin, an intracellular calcium binding protein previously found in distal convoluted tubules from all mammalian species that have been studied and able to increase, in vitro, Ca2+ reabsorption. We have shown by using in situ hybridization, immunoblotting and immunohistochemistry that calbindin was expressed in three different portions of the distal nephron of the African giant rat. Calbindin was found in distal convoluted tubules, in cortical collecting tubules and in outer medullary collecting ducts. By contrast, in laboratory rat, calbindin was only found in distal convoluted tubules and undetectable in medullary collecting ducts. Thick ascending limb of Henle's loop were calbindin negative as shown by double immunolabelling using anti-uromucoid (Tamm-Horsfall protein). As previously shown in laboratory rat and rabbit, transcellular Ca2+ movement seems to be facilitated by calbindin in renal tubules segments predominantly actively transporting Ca2+, it may be suggested that in African giant rat, outer medullary collecting ducts may also actively transport Ca2+. As calretinin, another intracellular calcium binding protein highly homologous to calbindin but whose function is still conjectural has been suspected to be expressed in kidney, we have looked and not found any calretinin in both adult rat species.
Inner ear malformations in patients with sensorineural hearing loss: detection with gradient-echo (3DFT-CISS) MRI.
The sensitivity of different MRI sequences in the detection of inner ear malformations in patients presenting with sensorineural hearing loss (SNHL) and/or vertigo was evaluated. We studied 650 patients presenting with SNHL and/or vertigo, clinically not suspected of having inner ear malformations. The sensitivity of T1-weighted, Gd-enhanced T1-weighted and (when available) T2-weighted spin-echo images, and three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) gradient-echo images, to unexpected malformations was assessed. Inner ear malformations were found in 15 (2.3%) of these patients. Enlargement of the endolymphatic duct and sac was the most frequent malformation, found in 11 patients. The 3DFT-CISS images showed all lesions; the other sequences were less sensitive and the pathology was missed, partially or only retrospectively seen in 11 of the 15 patients. Therefore, in addition to the routine unenhanced and Gd-enhanced T1-weighted and T2-weighted images, thin gradient-echo (3DFT-CISS) images are necessary to detect all clinically unexpected inner ear malformations in patients presenting with vertigo and/or SNHL.
Parvalbumin expression during developmental differentiation of the rat ovary.
Parvalbumin (PV) is a high-affinity Ca(2+)-binding protein which is expressed in a limited number of vertebrates tissues and restricted to a few distinct cell types. It has been shown by biochemical methods to be present in the adult rat ovary, but cellular localizations or developmental appearance have not been described until now. This study describes the presence of PV and its transcripts, analyzed by immunohistochemistry and in situ hybridization, respectively, during the postnatal development of the rat ovary: 13 developmental stages between day 1 and day 83 were examined. In ovaries 1-16 days old, neither PV mRNA nor PV was observed in any caaaaaaaaaaaaaay. By contrast, starting from day 18 postpartum, both PV mRNA and PV were detected in low amounts, simultaneously with the onset of differentiation of secondary intestitial gland cells in the ovarian interfollicular stroma. PV and its transcripts were primarily detected in conspicuous patches of interstitial gland tissue and in the differentiated thecal cells around the large follicles, and PV appeared to be fully expressed 33 days after birth. The parallel time courses of PV mRNA and PV accumulation during developmental differentiation, and the appearance of a steroid-producing cellular phenotype as well as the strict cellular colocalization of these two features, strongly suggest involvement of PV in the steroid metabolism of these cells, as earlier proposed for the Leydig cells of the testis. According to this hypothesis, we also show that suppression of gonadotrophic hormone production by hypophysectomy of adult rats totally suppresses PV production in parallel with the disappearance of the morphological features typical of steroid-producing cells in the remaining interstitial tissue of the ovary.
MR findings in müllerian duct cysts.
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MR imaging of a diverticulum in a female urethra.
The case of a 44-year-old woman with urethral diverticulum is described. The lesion was initially detected by ultrasonography. MRI proved to be very sensitive in localising and delineating the urethral diverticulum and could differentiate it from lesions arising from the vagina or bladder.
Detection of small mucosal and submucosal polyps with helical CT scanning in a patient with intestinal neurofibromatosis.
The detection of small (diameter 5-12 mm) mucosal jejunal polyps and small (diameter 14-26 mm) submucosal rectal polyps with helical C.T.-scanning in a patient with neurofibromatosis is described. Because a volume is scanned with helical CT, overlapping image reconstructions can be made allowing to produce a contiguous image set for cine mode display. The combination of 'volume scanning' with cine mode display helps in the dynamic visualization of the course of the intestinal loops. This might result in a better depiction of small lesions within the bowels and in a better differentiation between mucosal folds and the lesions.
Contribution of MRI and color Doppler sonography in breast cancer diagnosis.
Thirty female patients were examined with both MRI (30) and color Doppler sonography (24). MRI after injection of Gadolinium DTPA in combination with fast 3D FLASH sequences makes it possible to plot out signal-intensity changes over a certain period of time. Flow within a malignant breast lesion can be depicted with color Doppler sonography. The signal intensity increase pattern over a period of time, and the detection of color Doppler flow are of major importance for the differential diagnosis in breast cancer.
Determination of the new anticancer agent KW 2149, 7-N-[2-[2-(gamma-L-glutamylamino)ethyl)dithio)ethyl]mitomycin C, an analogue of mitomycin C.
The new mitomycin 7-N-[2-[2-(gamma-L-glutamylamino)ethyl)dithio)ethyl] mitomycin C (KW 2149) (I) proved to be active against a wide variety of experimental tumours. In order to perform pharmacokinetic studies with the new drug in Phase I sessions, a fast and reliable method has been developed based on the data of previous assays for mitomycin C. XAD-2 was preferred for isolation of I from blood plasma. The recovery of I was 50% whereas that of mitomycin C was 85%. Optimal separation was obtained on octadecyl silica columns with methanol-water (45:55, v/v) as mobile phase, while ultraviolet absorbance detection was performed at 375 nm. The assay enabled determination of I in a plasma concentration range of 20-1000 ng/ml using porfiromycin as internal standard.
Denta Scan: CT software program used in the anatomic evaluation of the mandible and maxilla in the perspective of endosseous implant surgery.
A radiological technique, using a new CT software program for the evaluation of alveolar process height and width, is presented. Irradiation is kept within acceptable limits when this technique is used. Measurements obtained with this technique were compared with those obtained on panoramic radiographs in 40 "half-jaws" (21 maxillar and 19 mandibular). We found that new indications for implantation emerge in the mandibular region because 'Denta Scan' can sometimes show possibilities to place implants on the buccal side of the canal (2 of 19 mandibular cases) when no possibilities are present above the canal on both the panoramic radiographs and Denta Scan images. In the maxillar region Denta Scan avoids unnecessary interventions by demonstrating the insufficient width of the alveolar ridge, often missed on panoramic radiographs (4 of 21 maxillar cases). Moreover the use of Denta Scan allows the use of implants with optimal length and diameter (23 of the 40 cases), giving better long-term results.
Bioanalysis of suramin in human plasma by ion-pair high-performance liquid chromatography.
A liquid chromatographic method is described that can be used for the determination of suramin in plasma samples from cancer patients treated with this drug. The chromatographic system is based on the use of tetrabutylammonium bromide as an ion-pairing agent, while ultraviolet detection is applied. The sample pretreatment is a simple deproteination step by an organic solvent. The same counter-ion as used in the phase system is added in order to increase the recovery of the almost complete protein-bound suramin. The minimum detectable concentration in plasma is ca. 0.1 microgram/ml, thus allowing the monitoring of patients treated with this drug. One example of a plasma concentration-time course after administration of suramin is given.
Differentiation expression during proliferative activity induced through different pathways: in situ hybridization study of thyroglobulin gene expression in thyroid epithelial cells.
In canine thyrocytes in primary culture, our previous studies have identified three mitogenic agents and pathways: thyrotropin (TSH) acting through cyclic AMP (cAMP), EGF and its receptor tyrosine protein kinase, and the phorbol esters that stimulate protein kinase C. TSH enhances, while EGF and phorbol esters inhibit, the expression of differentiation. Given that growth and differentiation expression are often considered as mutually exclusive activities of the cells, it was conceivable that the differentiating action of TSH was restricted to noncycling (Go) cells, while the inhibition of the differentiation expression by EGF and phorbol esters only concerned proliferating cells. Therefore, the capacity to express the thyroglobulin (Tg) gene, the most prominent marker of differentiation in thyrocytes, was studied in proliferative cells (with insulin) and in quiescent cells (without insulin). Using cRNA in situ hybridization, we observed that TSH (and, to a lesser extent, insulin and insulin-like growth factor I) restored or maintained the expression of the Tg gene. Without these hormones, the Tg mRNA content became undetectable in most of the cells. EGF and 12-0-tetradecanoyl phorbol-13-acetate (TPA) inhibited the Tg mRNA accumulation induced by TSH (and/or insulin). Most of the cells (up to 90%) responded to both TSH and EGF. Nevertheless, the range of individual response was quite variable. The effects of TSH and EGF on differentiation expression were not dependent on insulin and can therefore be dissociated from their mitogenic effects. Cell cycling did not affect the induction of Tg gene. Indeed, the same cell distribution of Tg mRNA content was observed in quiescent cells stimulated by TSH alone, or in cells approximately 50% of which had performed one mitotic cycle in response to TSH + insulin. Moreover, after proliferation in "dedifferentiating" conditions (EGF + serum + insulin), thyrocytes had acquired a fusiform fibroblast-like morphology, and responded to TSH by regaining a characteristic epithelial shape and high Tg mRNA content. 32 h after the replacement of EGF by TSH, cells in mitosis presented the same distribution of the Tg mRNA content as the rest of the cell population. This implies that cell cycling (at least 27 h, as previously shown) did not affect the induction of the Tg gene which is clearly detectable after a time lag of at least 24 h. The data unequivocally show that the reexpression of differentiation and proliferative activity are separate but fully compatible processes when induced by cAMP in thyrocytes.(ABSTRACT TRUNCATED AT 400 WORDS)
[Dynamic MRI of temporomandibular joint: technique and application].
Internal derangements or disk dysfunctions represent the most frequent pathology of the temporomandibular joint (TMJ). The radiological study of TMJ dysfunction was, for a long time, restricted to arthrography. More and more MR is used to study the TMJ, because MR, allows non-invasive visualisation of without the use of X-rays. Moreover a "dynamic" MR technique can be used to study disk movements during mouth opening. A lot of the internal derangement problems can be solved with this technique and arthrography can often be avoided. This dynamic MR technique is described and some cases are discussed.
Herniography in adults: review and personal studies.
In 120 adults (87 men, 33 women) with suspicion of a hernia but with normal physical examination, herniography disclosed 125 positive findings correlated with the clinical manifestations. There were no false positive or false negative herniographic diagnoses among 25 patients who underwent surgery. Herniography is a useful examination to evaluate patients with an uncertain or normal physical examination and with clinical manifestations suggestive for hernia. This relatively simple technique and the use of a non-ionic contrast medium are well tolerated.
Ultrasonographic findings in peptic ulcer: a report on 24 cases proven endoscopically.
A series of 24 patients is presented who had routine upper abdominal sonography for reason of atypical abdominal pain; in all cases the sonographically suggested diagnosis of a mucosal ulceration was proved by a following endoscopy. The ultrasonic findings were localized thickening of the gastric wall in combination with presence of liquid intragastrically in a fasting patient.
Giant angiomyolipoma with atypical arteriovenous shunting: CT and angiographic studies.
The advent of both ultrasound and computerized tomography made the pre-operative diagnosis of angiomyolipoma much easier. However, differentiation from retroperitoneal, perinephric space and especially intrarenal liposarcoma remains difficult or impossible. Angiographic findings are atypical and often do not allow differentiation from renal cell carcinoma. Early filling of the renal vein in renal cell carcinoma is sometimes used to distinguish renal cell carcinoma from angiomyolipoma. A case of a giant angiomyolipoma with arteriovenous shunting and early filling of the renal vein is described.
Structure of chick chromosomal genes for calbindin and calretinin.
The chick chromosomal gene for calbindin (the 28,000 Mr intestinal calcium-binding protein) was cloned, and all the exons and flanking regions were sequenced. The promoter region contains typical ATAAA and GGGCGG boxes, the latter being unusual in "non-housekeeping" genes. Three polyadenylation signals are found in the calbindin gene that correspond to the three known mRNAs. Transcription termination is not efficient because homology with consensus sequences found downstream from the polyadenylation signal is weak. There are ten introns, most of which do not fall at homologous positions, neither with respect to the sixfold repeating structure of the calbindin protein, nor with respect to previously sequenced genes for calmodulin and other calcium-binding proteins. The gene for the related protein calretinin was cloned and partially sequenced. The introns are in the same positions in the calretinin and calbindin genes. The introns have apparently been inserted during the divergence of the calcium-binding protein superfamily.