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Biomedical subjects

J Henning

Publications and source records attributed to J Henning.

At least 19 recordsLinked to original sources
PubMed2000

Prenylflavonoid variation in Humulus lupulus: distribution and taxonomic significance of xanthogalenol and 4'-O-methylxanthohumol.

The resins produced by either lupulin or leaf glands of over 120 plants of Humulus lupulus and one plant of H. japonicus (Cannabinaceae) were analyzed for the presence of prenylated flavonoids. The H. lupulus taxa investigated were H. lupulus var. lupulus from Europe, H. lupulus var. cordifolius from Japan, and H. lupulus from North America. Fifty-two of the plants examined were cultivars of European, American, and Japanese origin. Twenty-two flavonoids were detected in the glandular exudates of H. lupulus by HPLC-MS MS. Xanthohumol (3'-prenyl-6'-O-methylchalconaringenin) was the principal prenylflavonoid in all H. lupulus plants and was accompanied by 11 structurally similar chalcones. Ten flavonoids were identified as the flavanone isomers of these chalcones. Three other prenylchalcones were isolated from H. lupulus cv. 'Galena', one of which was identified as 3'-prenyl-4'-O-methylchalconaringenin (named 'xanthogalenol'). The distribution of three 4'-O-methylchalcones, i.e. xanthogalenol, 4'-O-methylxanthohumol, and 4',6'-di-O-methylchalconaringenin, was found to be limited to wild American plants from the Missouri-Mississippi river basin, H. lupulus var. cordifolius, and most of their descendents. These 4'-O-methylchalcones were absent from cultivars of European origin, and from wild hops from Europe and southwestern USA. The flavonoid dichotomy (presence versus absence of 4'-O-methylchalcones) indicates that there are at least two evolutionary lineages within H. lupulus (European and Japanese American), which is in agreement with morphological, molecular, and phytogeographical evidence. Leaf glands of H. japonicus from eastern Asia did not produce the H. lupulus prenylflavonoids.

Chromatography, High Pressure Liquid↗
PubMed1995

Induction, modification, and transduction of the salicylic acid signal in plant defense responses.

Studies in our laboratory as well as others strongly suggest that salicylic acid (SA) plays an important signaling role in plant defense against pathogens. We have found that increases in endogenous SA levels correlates with both resistance of tobacco to infection with tobacco mosaic virus and induction of defense-related genes such as that encoding pathogenesis-related protein 1 (PR-1). Some of this newly synthesized SA was conjugated to glucose to form SA beta-glucoside. A cell wall-associated beta-glucosidase activity that releases SA from this glucoside has been identified, suggesting that SA beta-glucoside serves as an inactive storage form of SA. By purifying a soluble SA-binding protein and isolating its encoding cDNA from tobacco, we have been able to further characterize the mechanism of SA signaling. This protein is a catalase, and binding of SA and its biologically active analogues inhibited catalase's ability to convert H2O2 to O2 and H2O. The resulting elevated levels of cellular H2O2 appeared to induce PR-1 gene expression, perhaps by acting as a second messenger. Additionally, transgenic tobacco expressing an antisense copy of the catalase gene and exhibiting depressed levels of catalase also showed constitutive expression of PR-1 genes. To further dissect the SA signaling pathway, we have tested several abiotic inducers of PR gene expression and disease resistance for their ability to stimulate SA production. Levels of SA and its glucoside rose following application of all of the inducers except 2,6-dichloroisonicotinic acid. 2,6-Dichloroisonicotinic acid was found to bind catalase directly and inhibit its enzymatic activity. Thus, it appears that many compounds that induce PR gene expression and disease resistance in plants inactivate catalases directly or indirectly.

Journal Article↗
PubMed1994

The pathway controlling the pupillary light reflex in urodeles.

Although the photomechanical response of the iris in amphibians has been characterized, the central pathway of reflex control is unknown. We investigated this pathway by electrophysiological and anatomical techniques in urodeles. Sustained responding neurons in the pretectum were localized and characterized. Three neuron types were found and compared with tonic neurons in mammals. They were driven by the contralateral retina and their dendrites arborized in the pretectal neuropil. The localization of cell bodies resulted in the identification of a physiological nucleus comparable with the nucleus praetectalis olivaris. It was shown that the tonic neurons project ipsi- and contralaterally to the oculomotor region, where axons terminate in deep layers of the stratum album. Using horseradish peroxidase transport the ciliary ganglion in urodeles was identified. It occurs in ontogenesis parallel to the first detectable pupillary light reflex corresponding to the onset of metamorphosis.

Animals↗
PubMed1987

[RARE-MR myelography in routine clinical practice. Experience with 175 cases].

In 1984 Henning, Nauerth, Friedburg and Ratzel described a new MRI data acquisition technique called RARE (Rapid Acquisition with Relaxation Enhancement). Several clinical applications have been published. A modification developed in the meantime, called "RARE hydrography", yields T2-weighted aqueous fluid specific images within a few seconds. As a nontomographic rapid approach to MR-myelography ("RARE-myelography") this technique is routinely applied at the beginning of all examinations of the spine. On the basis of 175 cases current potentials and limitations are discussed. Future applications of 3D-RARE myelography are mentioned.

Evaluation Studies as Topic↗
PubMed1987

Five-and-a-half years' experience with percutaneous retrogasserian glycerol rhizotomy in treatment of trigeminal neuralgia.

The results of treating trigeminal neuralgia with percutaneous retroganglionic glycerol rhizotomy in 319 patients from an overall series of 394 patients with 459 operations carried out over a period of 5 1/2 years are reported. Idiopathic trigeminal neuralgia was the diagnosis in 252 patients. 34 patients had trigeminal neuralgia associated with multiple sclerosis. The remaining 33 patients suffered from symptomatic trigeminal neuralgia or atypical facial pain. 230 patients (91.3%) with idiopathic trigeminal neuralgia and 30 patients (88.2%) with multiple sclerosis reported complete freedom from pain. In 12 patients (4.8%) of those with tic douloureux and in 1 patient (2.9%) with multiple sclerosis, pain was alleviated, and the patients required a reduced pharmacotherapy. 10 patients (3.9%) and 3 patients (8.8%) were considered to be treatment failures. The rate of recurrences within the first 2 years was 10.9 and 40.0%, respectively. In the long-term, the rate of recurrences in patients with tic douloureux was 36.9%. 144 patients (45.1%) noticed a hypesthesia. 132 patients (41.4%) had hypalgesia following the procedure, and there was a decrease of symptoms in the long-term observation in 20.0% of the patients. 59 patients (18.5%) developed dysesthesia postoperatively which regressed only to an inappreciable extent in the long-term course. In 16 patients (5.0%) exclusively with a preexisting organic lesion or who had received surgical pretreatment, there was a loss of corneal sensation. The investigation showed on the one hand the effectiveness of the method, but on the other hand also the possibility of marked sensory disorder in selected cases.

Administration, Cutaneous↗
PubMed1980

Studies on the cosubstrate site of protease solubilized NADPH-cytochrome P450 reductase.

Modification of the protease solubilized NADPH-cytochrome P450 reductase (= NADPH-cytochrome c reductase) at the critical SH group in the cosubstrate binding site affects KmNADPH but not V for the cytochrome c reduction. The increase of KmNADPH is dependent on the size and the charge of the substituent introduced. Substitution of the cosubstrate site SH by the CN-, S2O3- and the (N-ethyl) succinimido group effects a 3-, 7- and 23-fold increase of KmNADPH, respectively. The critical SH group in the NADPH binding region can be specifically radiolabeled by N-ethyl (2,3-14C) maleimide after preincubation of the reductase with unlabeled NEM in the presence of 1 mM NADP+. The selective reaction at the essential cysteine in the cosubstrate site is demonstrated by peptide mapping of the thermolytic digest and urea SDS gel electrophoresis of the cyanogen bromide fragments of the reductase. Protease solubilized NADPH-cytochrome P450 reductase is inactivated by reagents directed to histidine, arginine and lysine residues. NADP (H) (1 mM) and 2'-AMP (1 mM) give effective protection only for the reaction of 1,2-cyclohexanedione (12 mM). The functional role of the basic amino acid residues for the cosubstrate binding by the NADPH-cytochrome P450 reductase cannot be established therefore by the modification experiments described. The number of NADPH binding sites in the NADPH-cytochrome P450 reductase is determined to one site/mol reductase by titration of the enzyme with NADP+ monitored by CD-spectroscopy.

Amino Acids↗
PubMed1978

Polyethylene glycol-mediated infection with avian sarcoma viruses.

In this communication we report that fusion of viral and cellular membranes by polyethylene glycol is a convenient approach to overcoming genetically determined resistance to infection. Using this method, avian sarcoma virus-transformed mammalian cells have been produced which serve as useful model systems for the study of Rous sarcoma virus-specific tumor antigens.

Animals↗
PubMed1978

Immunodiffusion studies on Schistosoma mansoni and its host stage specific antigens. 1. Immunoelectrophoresis cross-reactions between S. mansoni adults and larval stages antigens.

IMMUNOELECTROPHORESIS was applied to evaluate the immunologic relationship between the different stages in the life cycle of Schistosoma mansoni (S.m.). The preparation of antigens and antisera was described. Separated female and male adult worms tested seem to be identical. Eggs, miracidia and cercariae from Biomphalaria glabrata and Biomphalaria alexandrina showed varying degree of cross-reactions. The maximal number of pricipitin arcs was observed, when anti-miracidia-serum was checked against all other S.m. antigens.

Animals↗
PubMed1978

Immunodiffusion studies on Schistosoma mansoni and its host stage specific antigens. 2. Immunoelectrophoresis cross-reactions between hepato-pancreas of Biomphalaria glabrata and Biomphalaria alexandrina.

IMMUNOELECTROPHORESIS was used for studies on immunological cross-reactions between both Schistosoma mansoni (S. m.) intermediate host snails Biomphalaria glabrata and Biomphalaria alexandrina. The preparation of antigens and their corresponding antisera from hepato-pancreas of S. m. infected and non infected snails was described as the homologous reactions of both snails either infected or non infected were rather similar, close immunological relationship between B. glabrata and B. alexandrina could be deduced.

Animals↗
PubMed1978

Immunodiffusion studies on Schistosoma mansoni and its intermediate host stage specific antigens. 3. Immunoelectrophoresis cross-reactions between S. mansoni stages and Biomphalaria sp. hepato-pancreas antigens.

IMMUNOELECTROPHORESIS was applied for cross-wise checking of the different stages in the life cycle of schistosoma mansoni with extracts of hepato-pancreas from its intermediate host snails Biomphalaria glabrata and Biomphalaria alexandrina. Only few fractions were common to non infected snail organ and parasite development stage, while more crossreactions were detected with infected snail hepato - pancreas.

Animals↗
PubMed1976

Influence of diet on breeding and infectivity in mass cultivation of Biomphalaria glabrata.

Under well defined laboratory conditions as troughs, room temperature, humidity, water and air supply Biomphalaria glabrata was bred and kept. In feeding trials powder of pellets for mice and commercial fish food were used as high protein diet in comparison to poor protein diet consisting of lettuce only. The high protein diet resulted in more clutches and eggs per snail than the lettuce diet. Also the yield of cercariae in the rish protein group was much higher than in the group fed on on lettuce alone. The optimal amount of snails could be obtained by feeding pellet powder, fish food and lettuce.

Animals↗
PubMed1976

Influence of diet on breeding and infectivity in mass cultivation of Bulinus truncatus.

Under well defined laboratory conditions as troughs, room temperature, humidity, water, and air supply Bulinus truncatus was bred and kept. In a feeding trial high protein diet consisting of powdered mice pellets, commercial tropical fish food and lettuce was compared to poor protein diet of lettuce alone. Higher yield of clutches, eggs and cercariae were observed in the rich protein diet group, Bulinus and Biomphalaria Snail seem to be influenced by diet in the same way.

Animals↗