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Biomedical subjects

J Hesse

Publications and source records attributed to J Hesse.

At least 19 recordsLinked to original sources
PubMed2003

Simultaneous optical and electrical recording of single gramicidin channels.

We report here an approach for simultaneous fluorescence imaging and electrical recording of single ion channels in planar bilayer membranes. As a test case, fluorescently labeled (Cy3 and Cy5) gramicidin derivatives were imaged at the single-molecule level using far-field illumination and cooled CCD camera detection. Gramicidin monomers were observed to diffuse in the plane of the membrane with a diffusion coefficient of 3.3 x 10(-8) cm(2)s(-1). Simultaneous electrical recording detected gramicidin homodimer (Cy3/Cy3, Cy5/Cy5) and heterodimer (Cy3/Cy5) channels. Heterodimer formation was observed optically by the appearance of a fluorescence resonance energy transfer (FRET) signal (irradiation of Cy3, detection of Cy5). The number of FRET signals was significantly smaller than the number of Cy3 signals (Cy3 monomers plus Cy3 homodimers) as expected. The number of FRET signals increased with increasing channel activity. In numerous cases the appearance of a FRET signal was observed to correlate with a channel opening event detected electrically. The heterodimers also diffused in the plane of the membrane with a diffusion coefficient of 3.0 x 10(-8) cm(2)s(-1). These experiments demonstrate the feasibility of simultaneous optical and electrical detection of structural changes in single ion channels as well as suggesting strategies for improving the reliability of such measurements.

Carbocyanines↗
PubMed2001

Gestures maintain spatial imagery.

Recent theories suggest alternatives to the commonly held belief that the sole role of gestures is to communicate meaning directly to listeners. Evidence suggests that gestures may serve a cognitive function for speakers, possibly acting as lexical primes. We observed that participants gestured more often when describing a picture from memory than when the picture was present and that gestures were not influenced by manipulating eye contact of a listener. We argue that spatial imagery serves a short-term memory function during lexical search and that gestures may help maintain spatial images. When spatial imagery is not necessary, as in conditions of direct visual stimulation, reliance on gestures is reduced or eliminated.

Adult↗
PubMed2000

[Diarrhea as the initial manifestation of medullary thyroid gland carcinoma].

BACKGROUND: With the differential diagnosis of a diarrhea a lot of causes has to be considered. In very rare cases diarrhea can be the first symptom of a medullary thyroid carcinoma (MTC). CASE REPORT: A 28-year-old patient came to the admission department because of persisting diarrhea. A computerized tomography revealed multiple hepatic and pulmonary metastases. A medullary thyreoid carcinoma was found as the cause of it. The serum calcitonin values were highly increased, later the carcinoembryonal antigen (CEA), too. Sandostatin, a radioimmune therapy (131J-anti-CEA antibody) and adriamycin were therapeutically applied. The patient died 24 months after the occurrence of the first symptoms. CONCLUSION: In case of persisting diarrhea the differential diagnosis of a medullary thyroid carcinoma must be taken into consideration and a calcitonin determination has to be arranged. Yet, typical symptoms like struma nodosa, swollen neck lymph nodes or a CEA increase can still be missing in the initial phase.

Adult↗
PubMed2000

Corf, the Rev/Rex homologue of HTDV/HERV-K, encodes an arginine-rich nuclear localization signal that exerts a trans-dominant phenotype when mutated.

Regulation of nucleo-cytoplasmic export of viral transcripts by a viral protein (Rev/Rex) is a characteristic feature in the replication cycle of complex retroviruses. We recently reported that the endogenous retrovirus family HTDV/HERV-K encodes a protein, Corf, that is a cellular Counterpart of Rev/Rex function and thus a new component of nucleo-cytoplasmic pathways. In HTDV/HERV-K-expressing cells, Corf is localized within the nucleoli. Here we describe the nuclear localization signal (NLS) of the Corf protein. Mutations in the NLS lead to cytoplasmic accumulation of the mutated protein and abrogate Corf function in a trans-dominant way.

Amino Acid Sequence↗
PubMed2000

Evaluation of scanners and CCD cameras for high-resolution TEM of protein crystals and single particles.

The modulation transfer function (MTF) and the geometric errors of two flatbed scanners, a slow-scan CCD (SSC) camera and film, have been measured and compared. The geometric errors of the SSC camera and film have been measured using diffraction spots from a lipid crystal. The SSC camera was shown to have the smallest geometric errors while film had the best MTF. Even though film had the best MTF, this is significantly reduced when scanning the film, so that the MTF of the film and scanner combined are comparable to the MTF of the SSC camera.

Biophysical Phenomena↗
PubMed1999

[Malaria--state of the art. I: Epidemiology, forms of malaria, diagnosis].

Year for year, some 2.1 million people die of malaria worldwide. In Germany, about 1,000 people go down with the disease after visiting malarious areas, and up to 3% will die--mostly of tropical malaria. Decisive factors for mortality are age over 60 and delays in effective pharmacological therapy. It is essential that, in the presence of an appropriate history, malaria be suspected early on. The diagnosis can still be established using the "thick drop", or a blood smear stained with Pappenheim's stain, or Diff-Quick. In the event of a strong suspicion, the two methods should be applied every 8 hours for three days.

Adult↗
PubMed1999

[Malaria--state of the art. 2: Therapy and prevention of malaria].

Suspected tropical malaria is an acute emergency. Immediate effective pharmacological treatment is of the essence. As in the case of prevention, various antimalarials are now available for treatment. Complicated tropical malaria requires treatment in hospital and intensive monitoring. The risk of infection and serious illness leading to a fatal outcome can be considerably reduced by suitable chemoprophylaxis or the use of stand-by medication for self-treatment, which, however, must be matched to resistance zones and the incidence of the four species of Plasmodium, in particular Plasmodium falciparum.

Adolescent↗
PubMed1999

Mitochondria-derived and extra-mitochondrial human type-1 porin are identical as revealed by amino acid sequencing and electrophysiological characterisation.

In mammalian cells porin channels are localised in both mitochondrial outer membranes and extra-mitochondrial membranes. We isolated mitochondria-derived porin of a human lymphoblastoid B cell line, determined its amino acid sequence and characterised its channel properties. Interestingly, the amino acid sequence of this porin preparation and, correspondingly, its electrophysiological characteristics in a reconstituted system were identical to those of 'Porin 31HL', the human type-1 porin purified from a crude membrane preparation of the same cell line using a different purification protocol. The results raise questions about targeting, insertion and orientation of human type-1 porin in different membranes.

Amino Acid Sequence↗
PubMed1998

[Prolonged non-convulsive status epilepticus as an early clinical manifestation of epilepsy in connection with HIV infection--case report with EEG and MRI follow-up].

The non-convulsive status epilepticus (NCSE) is a complication of petit mal epilepsy or epilepsy with temporal lobe seizures. Very rarely it is the primary manifestation of a symptomatic epilepsy. This report is on a 30-year old female inpatient with NCSE as the primary manifestation of symptomatic epilepsy, occurring four years after HIV infection (stage B3 according to the CDC classification) through heterosexual contact. After an initial tonic-clonic seizure, the patient suffered from NCSE for four weeks with diminished consciousness and major cognitive deficits. During this whole time period the EEG showed bilateral synchrone 1-2 Hz spike-wave complexes. After several failed treatment attempts, the NCSE was successfully and permanently treated with a combination of valproic acid and ethosuximide. The cerebrospinal fluid, cranial CT and cranial MRI were completely uneventful with regard to a CNS infection by the HI-virus or other infectious agents. 20 days after the initial symptoms, MRI showed bilateral cortical-subcortical and bilateral hippocampal lesions which stood out as focal edema zones, gradually disappeared completely and occurred in combination with the development of a discrete brain and right sided hippocampal atrophy. The EEG continued to show signs of right-temporal epileptic discharges with tendencies to generalise after 3 months but normalised after 6 months. Epileptic seizures are rarely an initial clinical sign of an infection with the HI-Virus even if no signs of encephalitis is detectable in the cerebrospinal fluid or in the cerebral MRI.

Adult↗
PubMed1994

Acupuncture versus metoprolol in migraine prophylaxis: a randomized trial of trigger point inactivation.

OBJECTIVES: To compare the effects of dry needling of myofascial trigger points in the neck region to metoprolol in migraine prophylaxis. DESIGN: Randomized, group comparative study. patients, investigator and statistician were blinded as to treatment, the therapist was blinded as to results. SETTING: Outpatient pain clinic in the northern Copenhagen area. Patients were referred by general practitioners or respondents to newspaper advertisements. SUBJECTS: Included were patients with a history of migraine with or without aura for at least 2 years. Excluded were persons with contraindications against treatment with beta blockers, chronic pain syndromes, pregnancy or previous experience with acupuncture or beta-blocking agents. A total of 85 patients were included; 77 completed the study. INTERVENTIONS: After a 4-week run-in period, patients were allocated to a 17-week regimen either with acupuncture and placebo tablets or to placebo stimulation and metoprolol 100 mg daily. RESULTS: Both groups exhibited significant reduction in attack frequency (P < 0.01). No difference was found between the groups regarding frequency (P > 0.20) or duration (P > 0.10) of attacks, whereas we found a significant difference in global rating of attacks in favour of metoprolol (P < 0.05). CONCLUSIONS: Trigger point inactivation by dry needling is a valuable supplement to the list of migraine prophylactic tools, being equipotent to metoprolol in the influence on frequency and duration (but not severity) of attacks, and superior in terms of negative side-effects.

Acupuncture Therapy↗
PubMed1987

Tubulin sequence region beta 155-174 is involved in binding exchangeable guanosine triphosphate.

Assembly-competent microtubule protein was directly photoaffinity labeled with [alpha-32P]guanosine triphosphate by UV irradiation. The labeled tubulin was digested with trypsin. The radioactive fragments were isolated and sequenced, revealing beta-tubulin residues 155-174 to be the major labeled region. An antibody to a synthetic peptide comprising residues beta 154-165 inhibits GTP incorporation and tubulin polymerization.

Affinity Labels↗
PubMed1985

Monoclonal antibodies localize the exchangeable GTP-binding site in beta- and not alpha-tubulins.

A combination of several methods was used to localize the exchangeable GTP-binding site in the alpha/beta-tubulin heterodimer: direct photoaffinity labeling with [alpha-32P]GTP, specific labeling of alpha- and beta-tubulin by tyrosylation and phosphorylation, respectively, and immunoprecipitation with specific monoclonal antibodies. Direct evidence was obtained that GTP binds exclusively to beta- and not alpha-tubulins.

Animals↗
PubMed1985

Properties of some monkey DNA sequences obtained by a procedure that enriches for DNA replication origins.

Twelve clones of monkey DNA obtained by a procedure that enriches 10(3)- to 10(4)-fold for nascent sequences activated early in S phase (G. Kaufmann, M. Zannis-Hadjopoulos, and R. G. Martin, Mol. Cell. Biol. 5:721-727, 1985) have been examined. Only 2 of the 12 ors sequences (origin-enriched sequences) are unique (ors1 and ors8). Three contain the highly reiterated Alu family (ors3, ors9, and ors11). One contains the highly reiterated alpha-satellite family (ors12), but none contain the Kpn family. Those remaining contain middle repetitive sequences. Two examples of the same middle repetitive sequence were found (ors2 and ors6). Three of the middle repetitive sequences (the ors2-ors6 pair, ors5, and ors10) are moderately dispersed; one (ors4) is highly dispersed. The last, ors7, has been mapped to the bona fide replication origin of the D loop of mitochondrial DNA. Of the nine ors sequences tested, half possess snapback (intrachain reannealing) properties.

Animals↗
PubMed1985

Acupuncture and transcutaneous electric nerve stimulation in the treatment of pain associated with chronic pancreatitis. A randomized study.

In 23 patients with pancreatitis, daily pain for at least 3 months, and no abuse of alcohol, the pain-relieving effect of electroacupuncture (13 patients) or transcutaneous electric nerve stimulation (TENS) (16 patients) was studied. In two prospective studies with a cross-over design, active acupuncture was compared with sham acupuncture, and TENS of the segmental points of the pancreas with sham treatment. Neither electroacupuncture nor TENS brought about pain relief that could substitute for or supplement medical treatment.

Acupuncture Therapy↗