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F Janssens

Publications and source records attributed to F Janssens.

18 recordsLinked to original sources
PubMed2003

Peliosis hepatis presenting as a multifocal hepatic pseudotumor: MR findings in two cases.

Two cases of pseudotumoral peliosis hepatis are presented with emphasis on MRI findings. One patient had four individual lesions, the other had two. Image characteristics in both were: heterogeneic signal intensity on T1-weighted images (T1WI) with areas of high-, intermediate, and low signal intensity; heterogeneic signal intensity on T2WI with presence of numerous intralesional "cystic" hyperintense areas with a hypointense border. Signal intensities on T1WI were iso- to hypointense in one case and mild central hyperintensities were demonstrated in the other case, probably due to intra-lesional hemorrhage or diffuse accumulation of fresh clotting within the sinusoids. One case demonstrated early enhancement of the peripheral borders in the arterial phase, and both demonstrated enhancement in the portovenous and late phases. One case was studied with Gd-BOPTA and iron oxides and demonstrated enhancement with both products, suggestive for the presence of hepatocytes and Kupffer cells. This is the first report of the use of hepato-specific contrast agents in this entity. Spontaneous regression of the lesions was demonstrated on a follow-up MR examination in one case.

Aged↗
PubMed2002

Pharmacological profile of (2R-trans)-4-[1-[3,5-bis(trifluoromethyl)benzoyl]-2-(phenylmethyl)-4-piperidinyl]-N-(2,6-dimethylphenyl)-1-acetamide (S)-Hydroxybutanedioate (R116301), an orally and centrally active neurokinin-1 receptor antagonist.

In comparison with a series of reference compounds, (2R-trans)-4-[1-[3,5-bis(trifluoromethyl)benzoyl]-2-(phenylmethyl)-4-piperidinyl]-N-(2,6-dimethylphenyl)-1-acetamide (S)-Hydroxybutanedioate (R116301) was characterized as a specific, orally, and centrally active neurokinin-1 (NK(1)) receptor antagonist with subnanomolar affinity for the human NK(1) receptor (K(i): 0.45 nM) and over 200-fold selectivity toward NK(2) and NK(3) receptors. R116301 inhibited substance P (SP)-induced peripheral effects (skin reactions and plasma extravasation in guinea pigs) and a central effect (thumping in gerbils) at low doses (0.08-0.16 mg/kg, s.c. or i.p.), reflecting its high potency as an NK(1) receptor antagonist and excellent brain disposition. Higher doses blocked various emetic stimuli in ferrets, cats, and dogs (ED(50) values: 3.2 mg/kg, s.c.; 0.72-2.5 mg/kg, p.o.). Even higher doses (11-25 mg/kg, s.c.) were required in mice (capsaicin-induced ear edema) and rats (SP-induced extravasation and salivation), consistent with lower affinity for the rodent NK(1) receptor and known species differences in NK(1) receptor interactions. R116301 inhibited the ocular discharge (0.034 mg/kg) but not the dyspnoea, lethality, or cough (>40 mg/kg, s.c.) induced by [betaALA(8)]-neurokinin A (NKA) (4-10) in guinea pigs, attesting to NK(1) over NK(2) selectivity. R116301 did not affect senktide-induced miosis (>5 mg/kg, s.c.) in rabbits, confirming the absence of an interaction with the NK(3) receptor. R116301 was inactive in guinea pigs against skin reactions induced by histamine, platelet-aggregating factor, bradykinin, or Ascaris allergens (>10 mg/kg, s.c.). In all species, R116301 showed excellent oral over parenteral activity (ratio, 0.22-2.7) and a relatively long duration (6.5-16 h, p.o.). The data attest to the specificity and sensitivity of the animal models and support a role of NK(1) receptors in various diseases.

Administration, Oral↗
PubMed2001

The role of MR imaging for the assessment of complicated duplex kidneys in children: preliminary report.

OBJECTIVE: To determine whether MR imaging, including MR urography, is able to assess complicated duplex kidneys and to determine the possible role of MRI compared to other imaging techniques in such uropathies. MATERIAL AND METHODS: Twenty consecutive patients (age 1 month-11 years) presenting with a suspicion of a complicated duplex kidney were prospectively studied with MRI and MR urography. The examinations were performed on a 0.5-T machine using routinely available sequences that were optimised to the patient's age and size. MR images were reviewed separately by two observers blinded to the patient history. They were asked to assess the presence of a duplex kidney, the presence of an abnormality that may require surgery and to indicate the type of the inferior ureteric insertion. A qualitative gradation of these results was performed on the basis of the final diagnosis provided at endoscopy (n = 6) or surgery (n = 14). MR results were compared to those provided by US examinations and excretory urography, when available, and a non-parametric statistical analysis was performed. RESULTS: MRI differentiated well between the upper and the lower poles of the kidneys and correctly answered the three questions in all 20 patients. The two observers agreed completely in all the 20 patients. MR was statistically superior to both US and excretory urography in the evaluation of the distal ureter (P < 0.05). CONCLUSIONS: MRI provides a precise assessment of the complications associated with duplex kidneys. Its optimal role seems to be the assessment of ectopic extra-vesical ureteric insertions and whenever an occult upper pole is suspected.

Child↗
PubMed1990

Recombinant human growth hormone treatment in short children with chronic renal disease, before transplantation or with functioning renal transplants: an interim report on five European studies.

Growth retardation is common in children with chronic renal disease. Final adult height is often reduced, even in children with a functioning renal transplant. The five European studies considered here aim to investigate the efficacy and safety of recombinant human growth hormone therapy (rhGH) in two groups of short children with chronic renal disease. The first group comprises 29 prepubertal children with preterminal chronic renal failure (i.e. before renal transplantation), and the second group comprises 39 prepubertal and pubertal children with functioning renal transplants. The median bone age retardation in the groups at the start of treatment was between 2.2 and 3.7 years; this did not change during the first year of treatment. This interim report concentrates on patients who have been treated for at least 1 year (i.e. 22 children from the first group, and 28 children from the transplant group (15 prepubertal and 13 pubertal children). The median height velocity increased from 4.8 cm/year to 10.0 cm/year in the first group (the chronic renal failure group), from 2.6 cm/year to 6.2 cm/year in prepubertal children with renal transplants and from 3.8 cm/year to 6.7 cm/year in pubertal children with renal transplants. The corresponding changes in height velocity SDS were from -1.3 to 5.1 for the chronic renal failure group and -2.8 to 2.3 for the prepubertal children with renal transplants. Renal function declined in the chronic renal failure group but this decline corresponded to expected progression of the disease. Some of the children with renal transplants showed a decreased renal function, which in most cases was explained by non-compliance or chronic rejection.

Adolescent↗
PubMed1986

Synthetic 1,4-disubstituted-1,4-dihydro-5H-tetrazol-5-one derivatives of fentanyl: alfentanil (R 39209), a potent, extremely short-acting narcotic analgesic.

The synthesis of a series of N-1,4-disubstituted-1,4-dihydro-5H-tetrazol-5-one piperidinyl derivatives of fentanyl, carfentanil, and sufentanil is described. The 1-substituted tetrazolinones 2 were essentially prepared via the addition reaction of aluminium azide to isocyanates or acid chlorides in tetrahydrofuran. Alkylation of 2 under neutral or weakly basic conditions afforded almost exclusively the 1,4-disubstituted tetrazolinone isomer 3. N-Alkylation of the piperidine derivatives 4 with 3 in dimethylformamide yielded 9a-v. The morphinomimetic activity in rats, after intravenous injection of the compounds, was evaluated in the tail withdrawal reflex test. The fentanyl analogues 9a-c (R4 = H) are inactive at the measured dose of 2.5 or 10 mg/kg (iv). For the carfentanil analogues (R4 = COOCH3) maximal narcotic activity is found when R1 represents a lower alkyl group (9d-f) or a thienylethyl group (9n). The sufentanil analogues (R4 = CH2OCH3) show the same structure-activity relationship (SAR) profile as the carfentanil derivatives (R4 = COOCH3). The structural requirements for optimal activity are in good agreement with earlier observations in the series of 10-12. From the series the ethyl tetrazolinone derivative 9r, alfentanil (R 39209), was selected for clinical investigation. As an analgesic in rats, 9r is 140 times more potent than pethidine 15 and 72 times more potent than morphine 14. Alftentanil reaches its peak effect within 1 min after injection, and its duration of action is very short; at 2 times its MED50, 9r has a duration of action of 11 min. This duration is 30 min for 10 and 90 min for 14. Compared to 10, alfentanil 9r is about 4 times faster but 3 times shorter acting. Structurally, 9r shows most resemblance to sufentanil 12, since it differs only by substitution of a 4-ethyltetrazolinone ring for the thiophene ring. The considerable differences in their pharmacological profiles were explained in terms of marked variations in physicochemical and, hence, pharmacokinetic properties.

Alfentanil↗
PubMed1985

New antihistaminic N-heterocyclic 4-piperidinamines. 1. Synthesis and antihistaminic activity of N-(4-piperidinyl)-1H-benzimidazol-2-amines.

The synthesis of a series N-(4-piperidinyl)-1H-benzimidazol-2-amines and the preliminary evaluation of their in vitro and in vivo antihistaminic activity are described. Cyclodesulfurization of (2-aminophenyl)thioureas with mercury(II) oxide resulted in 2-aminobenzimidazole intermediates, which were monoalkylated on the endo-nitrogen atom. After deprotection of the piperidine nitrogen atom with 48% aqueous hydrobromic acid solution, the title compounds were obtained by three different methods, viz. alkylation, reductive amination, or oxirane ring-opening reactions. The in vivo antihistaminic activity was evaluated by the compound 48/80 induced lethality test in rats and histamine-induced lethality test in guinea pigs after oral and/or subcutaneous administration. The duration of action, for a selected number of compounds, was studied in the guinea pig. The phenylethyl derivatives showed the most potent antihistamine properties after oral administration in both animal species.

Administration, Oral↗
PubMed1985

New antihistaminic N-heterocyclic 4-piperidinamines. 2. Synthesis and antihistaminic activity of 1-[(4-fluorophenyl)methyl]-N-(4-piperidinyl)-1H-benzimidazol-2-a mines.

The synthesis of a series of 1-[(4-fluorophenyl)methyl]-N-(4-piperidinyl)-1H-benzimidazol-2-ami nes and the preliminary evaluation of their in vivo antihistamine activity are described. The title compounds were obtained starting from either 1, 4, 10, or 55 by different synthetic methods. Substitution on the phenyl nucleus of the benzimidazole ring (84-87) was achieved by two different approaches. The in vivo antihistamine activity was evaluated by the compound 48/80 induced lethality test in rats and the antihistamine-induced lethality test in guinea pigs after oral and/or subcutaneous administration. The duration of action was studied in the guinea pig for three compounds (4, 51, and 55). Compound 51, "astemizole", was also studied in histamine- and serotonin-induced cutaneous reaction and for mydriatic activity in the rat and tested for peripheral and central effects not related to histamine antagonism in a variety of systems. Astemizole has been selected for clinical investigation.

Administration, Oral↗
PubMed1985

New antihistaminic N-heterocyclic 4-piperidinamines. 3. Synthesis and antihistaminic activity of N-(4-piperidinyl)-3H-imidazo[4,5-b]pyridin-2-amines.

To study the bioisosteric replacement of a 2-pyridyl ring for a phenyl nucleus in astemizole, a series of N-(4-piperidinyl)-3H-imidazo[4,5-b]pyridin-2-amines was synthesized and evaluated. The title compounds were obtained starting from either 8a or 8b by four synthetic methods. The in vivo antihistamine activity was evaluated by the compound 48/80-induced lethality test in rats and the histamine-induced lethality test in guinea pigs after oral and/or subcutaneous administration. Compound 37, the isostere of astemizole, showed the most potent antihistaminic properties in the rat. However, astemizole is superior to 37 as to duration of action and total potency.

Administration, Oral↗
PubMed1981

In vivo pharmacology of astemizole, a new type of H1-antihistaminic compound.

Astemizole (R 43 512), a chemically novel compound, has been studied for its in vivo histamine H1-antagonizing properties in laboratory animals. The test models used were: in rats, protection from compound 48/80-induced lethality and inhibition of histamine-induced skin reactions; in guinea-pigs, protection from histamine-induced fatality and bronchoconstriction and in dogs, inhibition of histamine-and Ascaris allergen-provoked skin oedema formation. When compared to standard antihistamines, astemizole showed a higher oral potency and a longer duration of action in all animal models studied. Astemizole's activity was highly specific: it exerted only weak antiserotonin and no anticholinergic actions. Behavioral and drug interaction studies showed that it was devoid of depressant or stimulatory effects on the central nervous system (CNS). Astemizole was very atoxic: safety margins were greater than 25,000 in rats and mice, 30,800 in guinea-pigs and greater than 2000 in dogs. The data of this study indicate that astemizole can be described as a potent, exceptionally long-acting and selective histamine H1-antagonist, free of central and toxic effects.

Animals↗
PubMedDate not supplied

Renal macronodular tuberculoma: CT and MR findings in an asymptomatic patient.

We present the case of a 50-year-old man with a solitary mass lesion in the right kidney. Characteristics on ultrasound were a thick irregular hypoechoic wall and a slightly hyperechoic center. Computed tomography depicted the lesion as spontaneously hyperdense at its base. After administration of intravenous iodinated contrast only partial enhancement in the peripheral wall was seen. On MR imaging the lesion was hypointense on T1-weighted images, and T2-weighted images demonstrated a thick irregular hypointense peripheral wall and an intralesional fluid debris level. Gadolinium-chelates were not administered.

Diagnosis, Differential↗
PubMedDate not supplied

Midgut volvulus in an adult patient.

The authors report on a case of midgut volvulus in a 27-year-old man who presented with bilious vomiting and acute abdominal pain. US demonstrated a reversal of the normal relationship between the superior mesenteric artery (SMA) and superior mesenteric vein (SMV). A clockwise whirlpool sign, diagnostic for midgut volvulus, was not visualised. In a further assessment, upper gastrointestinal series demonstrated obstruction in the second part of the duodenum highly suspicious of Ladd's bands. Malpositioning of bowel structures, as already suggested by the reversal of the SMA and SMV on ultrasound, and a distinctive whirl pattern due to the bowel wrapping around the SMA was demonstrated on CT. Furthermore angiography revealed focal twisting of the SMA. US is the first imaging modality to perform in suspicion of midgut volvulus. When inconclusive, CT is in our opinion the next stage in the diagnostic work-up.

Abdomen, Acute↗
PubMedDate not supplied

Proximal pulmonary artery aneurysm.

The authors report on a case of proximal pulmonary artery aneurysm detected on a routine chest X-ray. The scintigraphic and angiographic features of the condition are described and the importance of including the entity in the differential diagnosis of lung masses is stressed.

Adult↗
PubMedDate not supplied

Ureteral ectopy in the seminal vesicle associated with cyst formation and renal dysplasia: contribution of 3D-MRI.

A case of a congenital anomaly of the urinary tract in a 25-year-old Caucasian male is presented. Preoperative and pathologic findings demonstrated an ectopic ureter which terminated in a seminal vesicle cyst. Both structures formed an abortive common duct at the bladder base. The ipsilateral kidney was dysplastic. Findings on voiding cytourethrography, spiral CT, and MRI are discussed and correlated with pathologic findings. The authors suggest that MRI, especially with the use of 3D sequences, is the examination of choice in the evaluation of a complex congenital urogenital anomaly as presented.

Adult↗