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Biomedical subjects

J Mertens

Publications and source records attributed to J Mertens.

At least 73 records · Page 4Linked to original sources
PubMed1987

New high yield Cu(I) assisted 123I radioiodination of 15(p-I-phenyl)-9-methyl pentadecanoic acid, a potential myocardial tracer.

A new high yield 123I radioiodination (97%), based on the Cu(I) assisted isotopic exchange in an ethanol water mixture, of 15(p-I-phenyl)-9 methyl pentadecanoic acid, a potential myocardial tracer, is proposed. The method allows a true kit preparation of radioiodinated phenyl fatty acids for a substrate concentration of +/- 10(-6) moles. High specific activities (greater than 0.1 mCi/micrograms) can be obtained when coupling the labelling method to HPLC purification with an overall radiochemical yield of 75%.

Fatty Acids↗
PubMed1987

[Antimicrobial action of rolitetracycline in gelatin sponge packs (Marbagelan) in tympanoplasty].

Gelatine sponge packs (Marbagelan) saturated in rolitetracycline (Reverin) were evaluated. The antimicrobiotic efficacy of the substance was determined in 26 packs before insertion and in 20 packs removed from the external ear meatus after varying periods. High concentrations of rolitetracycline were found independent of saturation grade in the packs before insertion. In the packs removed from the external meatus acceptable antimicrobial activity was found independent of the time the packs remained in the ear. An efficient prophylaxis against infection in ear surgery is guaranteed.

Ear, Middle↗
PubMed1986

Fast, low-temperature preparation of carrier-free 17-123I-heptadecanoic acid applied for liver and heart scintigraphy.

A high-yield method for labelling 17-I-heptadecanoic acid with 123I is described, and a clinical evaluation of the radiopharmaceutical is given. The labelling procedure is based on the use of a conventional ultrasonic bath. It was found that the addition of thiosulphate to the reaction medium avoids the formation of labelled side products and increases the yield considerably. The carrier-free 17-123I-heptadecanoic acid (2 mCi) in 6% human serum albumin was injected IV for heart and liver studies on selected patients with cirrhosis (alcoholic, post-necrotic) and diabetes.

Diabetes Mellitus, Type 1↗
PubMed1986

[Sudden deafness caused by rupture of the round window membrane. Surgical indications, course and prognosis].

Tympanotomy was performed on 39 of 247 patients with sudden hearing loss between 1980 and 1982. In 23 cases a round window membrane defect was found. Evaluation of the indications, intraoperative findings and postoperative course allows the following conclusions to be drawn. Only in patients treated in the second week was the rate of success significantly higher than the spontaneous remission rate in patients without perilymphatic fistula. If there is no improvement in the hearing level in the first week after covering a round window membrane defect the prognosis is poor. Stabilization of the hearing is complete in the first three weeks after treatment. Prognosis in extensive membrane defects with large perilymphatic fistulas is definitely worse than in small round window membrane defects. The best results were achieved for the following groups: physical exertion/barotrauma, sudden deafness, progressive hearing loss despite drug therapy.

Aprotinin↗
PubMed1985

Influence of microbial bile salt desulfation upon the fecal excretion of bile salts in gnotobiotic rats.

The fecal excretion of intraperitoneally injected 24-14C-labeled taurocholate (TCA), taurolithocholate (TLCA) and the respective 3-sulfate esters (TCA-3-S; TLCA-3-S), were compared in germfree (GF) rats, conventional (CV) rats, and in gnotobiotic rats associated with Clostridium Cl-8 or this same strain Cl-8 plus the bile desulfating Clostridium S1, respectively. TCA and TLCA were about two times more rapidly excreted by CV animals than by GF animals; the time required for 50% excretion of total label injected (t 1/2) was 6.6 days vs 14.9 for TCA, and 4.4 vs 8.9 for TLCA. In GF and in CV animals, TCA-3-S and TLCA-3-S were excreted more rapidly than their nonsulfated analogues; the t 1/2 values of TCA-3-S and TCA were 2.7 days vs 14.9 in GF rats, and 3.1 vs 6.6 days in CV animals. The t 1/2 values of TLCA-3-S and TLCA were 2.7 days vs 8.9 in GF rats, and 1.5 vs 4.4 days in CV rats. In gnotobiotic rats associated with Clostridium strains S1 + Cl-8, fecal bile salts were nearly 100% deconjugated and desulfated and the 50% excretion times of TCA-3-S and TLCA-3-S approximated to those of TCA and TLCA in GF animals. T 1/2 of TCA-3-S in gnotobiotic S1 + Cl-8 animals was 12.2 days vs 14.9 for TCA in GF animals. In gnotobiotic S1 + Cl-8 animals the t 1/2 of TLCA and TLCA-3-S was 12.5 and 11.0 days, respectively. These results illustrate clearly the important effect the intestinal microflora has upon the metabolic half-life of bile salts. Moreover, they demonstrate that desulfation of bile salts by the intestinal microflora takes place in intestinal segments from where a certain degree of reabsorption is still possible, and thus point to the fact that microbial desulfation is an important variable in the overall elimination of bile salts.

Animals↗
PubMed1985

[Format filling photodocumentation with the flexible endoscope Olympus ENF-P using a new objective combination].

Photographic documentation is an important part of endoscopy. A flexible endoscope of small diameter, developed for special use in ENT is described. The resulting photographs fill the slide ("format filling"). This new objective combination fulfills the requirements of endoscopic construction and permits good photographic documentation of concealed parts of the ear, nose and throat which cannot be achieved by conventional rigid endoscopes.

Endoscopes↗
PubMed1984

[Flexible fiber endoscopy in ENT].

The range of visual examination and therapeutic procedures in the field of ear, nose and throat surgery has been expanded by the combination of the flexible fiberscope with the rigid telescope. The following are the advantages of the flexible fiberscope: 1. Increased accessibility, 2. less patient discomfort, 3. easier insertion technique, 4. low incidence of the accidental injuries, 5. simplified documentation by photography. In addition, these procedures can be performed on a routine and outpatient basis.

Adolescent↗
PubMedDate not supplied

Isolation and pharmacological characterization of vernolepin.

Vernolepin, a sesquiterpene lactone, was isolated from the dried fruit of Vernonia amygdalina Del. The different steps used during the extraction were: continuous extraction with chloroform, partition of the chloroform-extract between pertroleum ether and 10% aqueous methanol, column chromatography of the methanol extract, isolation of the active fractions by pharmacological and chemical characterization. Vernolepine was obtained as colorless prisms and identified by melting point, uv, ir, 1H nmr, optical rotation, and mass spectrometry. The total content of the dried fruit was 0.09% vernolepin. The first pharmacological characterization of vernolepin revealed: (1) a competitive antagonism against histamine in guinea pig ileum (pA2 = 5.61; 15 min incubation); (2) a biphasic enhancement/inhibition of coaxial stimulation of guinea pig ileum; (3) an antiaggregating and disaggregating activity against rabbit platelet aggregation induced by arachidonic acid (1 X 10(-4) g/ml; 3.3 X 10(-4)M) or ADP (4 X 10(-6) g/ml; 1 X 10(-5)M) without inhibition of cyclo-oxygenase or lipoxygenase. All these reactions were time dependent and occurred at concentrations of 5 X 10(-6) to 1 X 10(-5) g/ml vernolepin (1.8 to 3.5 X 10(-5)M).

Africa↗
PubMedDate not supplied

Fibromuscular dysplasia of the superior mesenteric artery--case report and review of the literature.

Fibromuscular dysplasia is a multifactorial arteriopathy most commonly affecting the renal and carotid arteries. In this report we present a case of visceral artery involvement, causing occlusion of the superior mesenteric artery and celiac trunk and resulting in visceral ischemia. Treatment consisted of superior mesenteric artery reimplantation. Visceral artery FMD can present as occlusive or aneurysmal disease and treatment depends on patient characteristics and symptoms.

Abdominal Pain↗
PubMedDate not supplied

Regional binding index of the radiolabeled selective 5-HT2A antagonist 123I-5-I-R91150 in the normal canine brain imaged with single photon emission computed tomography.

The pattern of the specific 5-HT2A (5-hydroxytryptamine 2A receptor) antagonist 123I-5-I-R91150 was measured in 10 healthy dogs without neurologic and behavior abnormalities. Eight cortical regions (left and right fronto-, temporo-, parieto-, and occipitocortical area), one global subcortical region (including the thalamic system) were compared with a reference region lacking receptors; that is, the cerebellum. The 123I labeled radioligand was injected intravenously 100-200 minutes before acquisition. Both transmission and emission data were obtained with a triple head gamma camera equipped with high-resolution fanbeam collimators. The emission data were corrected for scatter and attenuation. To delineate different cerebral regions more accurately, the regions of interest (ROI) defined in a former study on brain perfusion measured with 99mTc-ethyl cysteinate dimer (ECD) in the same dogs were used. The co-registration of the 99mTc-ECD and the 123I-5-I-R91150, obtained from each dog, was realized with the help of corresponding transmission maps. By normalizing each regional cerebral activity to the activity observed in the cerebellum, the regional radioactivity (binding index) could be relatively quantified. Highest brain uptake was noted in the frontocortical brain areas (right: 1.85, left: 1.89), followed by the temporocortical region (right: 1.58, left: 1.56). Least uptake was noted in the more caudal and middle brain regions [occipito- (right: 1.46, left: 1.41), parietocortical (right: 1.30, left: 1.26), and striatal region (1.19)]. No gender nor age influence was noted in this series. The 123I labeled serotonin-2A receptor ligand seems to have similar cortical binding in the normal canine brain, as shown in humans and other animal species. A frontocortical to occipitocortical (rostrocaudal) binding index gradient was identified within the dog, which has not been seen in imaging studies from humans and other animal species. The significance of these results will need further investigation. This normative data can be used to compare regional brain uptake of the 123I-radioligand to dogs with behavioral disorders related to the serotonergic system, in future studies.

Animals↗