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Biomedical subjects

C Zech

Publications and source records attributed to C Zech.

9 recordsLinked to original sources
PubMed2006

[Cine MRI of the thorax in patients with pectus excavatum].

BACKGROUND: Morphologic and dynamic assessment of respiratory chest kinetics was performed in patients with pectus excavatum deformity (PE) using dynamic MRI: cine MRI. MATERIAL AND METHODS: Seven consecutive patients with PE (aged 20.3 years+/-4.0) and ten healthy volunteers of comparable age underwent real-time cine MRI of the chest during breathing on a 1.5 T MR scanner (Magnetom Sonata, Siemens Medical Systems, Erlangen, Germany) using a standard phased array body coil and a half-Fourier single-shot turbo spin echo sequence (HASTE) for dynamic imaging. During deep inspiration and expiration, single-shot sequences were performed in one slice level over 20 s at a frequency of 1 image/s covering the entire thoracic cage in three orientations. Morphology and chest kinetics in patients with PE were analyzed and compared with normal values, and typical patterns of chest kinetics were noted. RESULTS: Three different types of chest morphology in PE were identified: (1) the generally flattened thoracic cage, (2) the "tilted" sternum, and (3) the focally deepened sternum. Three patterns of motion correspond to these morphological types: (1) elevation of the sternum and the anterior thoracic wall, (2) angulated elevation of the parasternal rib cage with persistent deepening of the sternum resembling a "wing beat" movement, and (3) increased diaphragmatic movements with limited chest wall dynamics. CONCLUSIONS: Cine MRI is an adequate radiation-free diagnostic modality for the dynamic imaging of both chest morphology and chest wall kinetics in patients with PE. The pectus severity index can easily be determined and three typical movement patterns of chest wall kinetics identified.

Adolescent↗
PubMed2000

[Persistent hyperplastic primary vitreous syndrome in a girl with Aicardi syndrome].

Aicardi syndrome is characterized by infantile spasms, agenesis of the corpus callosum and chorioretinal lacunae. This disorder affects mostly females with early embryonic lethality in males. We present a case of persistent hyperplastic primary vitreous (PHPV) in association with Aicardi syndrome in a 2-year-old girl.

Abnormalities, Multiple↗
PubMed1999

Transient acute myopia induced by antilymphocyte globulins.

Acute onset of transient myopia may be induced by several drugs, different mechanisms having been described. We report the occurrence of such an event after intravenous administration of equine antilymphocyte globulins in a patient treated for aplastic anemia. Clinical ocular examination revealed no other abnormality, and ultrasonography disclosed no swelling of the ciliary body. The drug-induced myopia resolved completely after instillation of topical cyclopentolate, suggesting that its mechanism was the occurrence of a ciliary spasm. Acute myopia is a rare event and, to the authors' knowledge, this represents the first case described as being induced by antilymphocyte globulins.

Acute Disease↗
PubMed1998

[Capsular bag distension syndrome after capsulorhexis].

We present one case of capsular bag distension associated with lens phacoemulsification, capsulorhexis and posterior chamber intraocular lens (IOL) insertion. Capsular bag distension is a rare postoperative complication of continuous tear anterior capsulotomy and presents the following characteristics: (1) postoperative myopic over-refraction; (2) shallowing of the anterior chamber associated with anterior shift of the IOL and the iris diaphragm; (3) important posterior distension of the posterior capsule and (4) sealing of the capsule to the anterior surface of the IOL. In our case, recovery of vision was incomplete after cataract surgery although the procedure was uneventful and no other ocular pathology was found. A neodymium: YAG laser anterior capsulotomy peripheral to the edge of the IOL remedied the situation allowing the capsular fluid to regress into the anterior chamber and the IOL to return in a normal posterior position.

Aged↗
PubMed1991

Novel sites for phenylalkylamines: characterisation of a sodium-sensitive drug receptor with (-)-[3H]emopamil.

(-)-Emopamil ((S)-emopamil, (2S)-2-isopropyl-5-(methylphenethylamino)- 2-phenylvaleronitrile hydrochloride) is a Ca(2+)-antagonistic phenylalkylamine which also blocks serotonin (5-HT2) receptors and has antiischemic properties. The (-)-[3H]emopamil tissue distribution profile of specific binding is in striking contrast to that observed for (+)-[3H]PN 200-110 or (-)-[3H]desmethoxyverapamil: (-)-[3H]emopamil labels membrane fractions from guinea-pig liver much greater than adrenal gland greater than kidney approximately lung approximately ductus deferens approximately brain approximately skeletal muscle. Binding to liver membrane was saturable (KD = 12.8 nM, Bmax = 35 pmol/mg of protein), stereoselective, reversible (K-1 = 0.22 min-1 at 25 degrees C) and inhibited by tetraethylammonium (IC50: 1.8 mM) greater than Li+ (IC50: 12.5 mM) approximately Na+ (IC50: 13.6 mM) and [NH4+] (IC50: 79.3 mM) but not by Rb+, Cs+ or K+. The high-affinity liver membrane binding sites have a pharmacological profile that is distinct from the phenylalkylamine receptor domain of the voltage-dependent L-type Ca2+ channel. Similar sites exist in brain and other tissues, albeit with a lower density. Amiodarone, butoprozine and amiloride derivatives bind with high affinity whereas 1,4-dihydropyridines do not interact at all. It is suggested that the novel phenylalkylamine site is linked to a sodium-dependent carrier or transport system.

Animals↗
PubMed1991

Very high affinity interaction of DPI 201-106 and BDF 8784 enantiomers with the phenylalkylamine-sensitive Ca2(+)-channel in Drosophila head membranes.

1. Piperazinylindoles (DPI 201-106, BDF 8784), drugs known to act on voltage-dependent Na(+)-channels, bind with very high affinity to a Ca2(+)-channel-associated phenylalkylamine receptor in Drosophila melanogaster head membranes. These compounds and (+)-tetrandrine, a naturally occurring Ca2(+)-antagonist, were the most selective inhibitors for phenylalkylamine-labelled Drosophila Ca2(+)-channels compared to mammalian L-type Ca2(+)-channels. 2. Replacement of the cyano group by a methyl group in (+)-DPI 201-106 ((+)-BDF 8784) increases the IC50 value for inhibition of phenylalkylamine labelling of Drosophila Ca2(+)-channels from 0.29 to 2.1 nM but decreases the IC50 value for inhibition of phenylalkylamine labelling of mammalian skeletal muscle Ca2(+)-channels from 3480 to 49 nM. 3. DPI 201-106 enantiomers completely block (at 0.1 microM) phenylalkylamine photolabelling of a 136 K polypeptide in Drosophila head membranes whereas 10 microM aconitine or lidocaine are without effect. 4. Assessment of the Ca2(+)-antagonist effects of the substituted DPI 201-106 enantiomers in K(+)-depolarized taenia strips from guinea-pig caecum yielded pA2 values of 6.33 +/- 0.07 for (-)-BDF 8784 and 6.99 +/- 0.17 for (+)-BDF 8784, respectively. 5. Piperazinylindoles, previously believed to act nonspecifically on voltage-dependent mammalian L-type Ca2(+)-channels, therefore have stereoselectivity for a novel binding site and chemical selectivity unrelated to local anaesthetic activity. 6. It is proposed that a very high affinity piperazinylindole-selective site is coupled to the phenylalkylamine receptor of Drosophila Ca2(+)-channels. These sites are still present on mammalian L-type Ca2(+)-channels but have lower affinity and/or are less tightly coupled to phenylalkylamine receptors on the alpha 1-subunit.

Affinity Labels↗
PubMed1990

Mitochondrial Ca2+ antagonist binding sites are associated with an inner mitochondrial membrane anion channel.

The inner mitochondrial membrane contains specific Ca2+ antagonist binding sites unrelated to the L-type Ca2+ channel. The mitochondrial 1,4-dihydropyridine (DHP) and phenylalkylamine sites are reciprocally allosterically coupled, require anions (e.g., Cl-, No3-) for optimal binding, and are inhibited by purine and pyrimidine nucleotides in a noncompetitive manner. In mitochondrial swelling experiments, a concentration-dependent inhibition of an inner mitochondrial membrane anion channel (IMAC) by Ca2+ antagonists from different chemical classes can be demonstrated. Under the conditions of the swelling experiments, affinity of different Ca2+ antagonists and amiodarone, a known IMAC inhibitor, for the mitochondrial (+/-)-[3H]nitrendipine binding site (Kd, 7.2 +/- 2.0 microM; Bmax, 1.03 +/- 0.37 nmol/mg of protein) strongly correlated with their inhibitory potency for the IMAC. Linear regression of pIC50 values for IMAC-induced swelling versus pIC50 values for (+/-)-[3H]nitrendipine binding inhibition yielded a correlation coefficient of 0.91 for all tested DHPs (n = 12, p less than 0.001). Amiodarone inhibited (+/-)-[3H]nitrendipine binding and IMAC-induced swelling with pIC50 values of 6.11 and 5.93, respectively. The correlation coefficient between binding and inhibition of IMAC-induced swelling for amiodarone and all tested Ca2+ antagonists (including non-DHP compounds) was 0.76 (n = 20, p less than 0.001), with the slopes approaching unity. These results suggest the association of the mitochondrial Ca2+ antagonist binding sites with an IMAC.

Amiodarone↗
PubMed1989

Efficiency gains in utilization review.

A study was conducted to determine which Major Diagnostic Categories (MDCs) accounted for most of the nonessential hospital admissions in 73 Michigan hospitals in 1986. The Intensity, Severity, Discharge-Appropriateness (ISD-A) criteria set was used to identify nonessential admissions. Large concentrations of nonessential admissions were found in medical, psychiatric, and substance abuse cases; surgical admissions had low rates of nonessential hospitalization. Focusing utilization review on MDCs with nonessential rates exceeding 15% results in an examination of 44% of admissions, while capturing 77% of nonessential admissions and 73% of potential dollar savings. Implications for UR activities are discussed.

Age Factors↗