Search PubMed⌕ Search

Biomedical subjects

K Hoffmann

Publications and source records attributed to K Hoffmann.

At least 181 records · Page 10Linked to original sources
PubMed1997

[Quality of life, needs and treatment evaluation of long-term hospitalized patients. Part II of the Berlin Deinstitutionalization Study].

OBJECTIVE: Objective living situation, subjective quality of life, need for care, and assessment of treatment of long-term hospitalised patients were investigated. METHODS: 237 patients from 6 hospitals were examined using standardised instruments. RESULTS: Patients' satisfaction was generally relatively high, but varied greatly in subgroups and individuals. Patients were most satisfied with personal safety in the hospital and least satisfied with the expectation to live in the hospital for a long time. Therapists assessed clearly more needs for care in the patients than the patients did themselves. Statistical analysis revealed significant correlations between the subjective quality of life in different domains, the number of needs stated and plausible determining factors. CONCLUSIONS: Findings reflecting patients' living situation in the hospital are very heterogeneous. In respect of subjective evaluation criteria, there is little space for improvement in the future.

Activities of Daily Living↗
PubMed1996

Binding of immunophilins to the 90 kDa heat shock protein (hsp90) via a tetratricopeptide repeat domain is a conserved protein interaction in plants.

In animal cell lysates, multiprotein complexes containing hsp90, hsp70, p60, p23, and several immunophilins can assemble steroid receptors and oncogenic protein kinases, such as v-Src and v-Raf, into heterocomplexes that contain hsp90 and either immunophilins or, in the case of protein kinases, p50. The complexes with hsp90 are required for the proper functioning of these signal transduction systems. Wheat germ lysate contains a similar protein folding activity that forms functional steroid receptor complexes with hsp90, but not all the components of this system have been identified. The plant chaperone system has conserved interactions with animal chaperones in that wheat hsp70 functions in the rabbit reticulocyte lysate heterocomplex assembly system and human p23 functions in the wheat germ lysate. Here, we ask if wheat germ lysate also contains immunophilins of the FK506-binding class (FKBPs) that bind to the hsp90 component of the chaperone complex via tetratricopeptide repeat (TPR) domains. To demonstrate the plant heterocomplex, we add purified mammalian p23, preadsorbed with the JJ3 antibody to protein A-Sepharose, to wheat germ lysate and allow ATP-dependent formation of an animal p23. plant hsp90 complex. The complex is then washed and incubated with the radiolabeled immunosuppressant drug [3H]FK506, which binds in a specific manner to a coimmunoadsorbed plant FKBP. Binding of the plant FKBP to plant hsp90 is prevented by adding to wheat germ lysate a purified fragment containing the TPR domains of human cyclophilin-40. Geldanamycin, a benzoquinone ansamycin that binds to animal hsp90s and prevents their chaperone activity, binds in a temperature-dependent manner to wheat hsp90 to block formation of the p23.hsp90.FKBP heterocomplex. These data show that immunophilin binding to hsp90 via TPR domains is conserved in the plant kingdom as well as in the animal kingdom and that geldanamycin will be an important tool for the study of hsp90-mediated protein chaperoning in plant cells.

Adenosine Triphosphate↗
PubMed1996

Induction of 5-aminolevulinate synthase by drugs is independent of increased apocytochrome P450 synthesis.

To investigate the role of newly synthesized apocytochrome P450 (P450) in the regulation of 5-aminolevulinate synthase (ALAS), we overexpressed P450 in primary cultures of chick embryo hepatocytes and measured the subsequent effects on ALAS mRNA by semiquantitative RT-PCR. Hepatocytes were co-transfected with a vector for expression of P450 cDNAs (CYP3A4 or CYP2H1) and a vector directing the synthesis of a cell surface antibody. Transfected hepatocytes were isolated with hapten-coated magnetic beads at different times after electroporation (4, 8 and 20 h). Overexpression of human CYP3A4 was demonstrated by high levels of the corresponding mRNA and apoprotein as analyzed by RT-PCR and western-blot analysis. Similarly, chicken CYP2H1 was expressed to levels even higher than those induced with phenobarbital. However the level of ALAS mRNA did not change in these cells. Our results demonstrate that the induction of ALAS by drugs is not a direct consequence of increased P450 apoprotein synthesis and heme utilization.

5-Aminolevulinate Synthetase↗
PubMed1996

Analysis and classification of interictal spike discharges in benign partial epilepsy of childhood on the basis of the Hilbert transformation.

The spatial distribution of instantaneous power during the occurrence of rolandic spikes (computed via Hilbert transformation) can be utilized for classification of topographically different spike types. By visual analysis of the instantaneous power maps we found seven characteristic spike classes which correspond to the results of visual analysis of potential distribution. A neural network (NN) was trained with representatives of these classes. Single instantaneous power maps of 55/56 visually selected rolandic spikes, as well as map sequences of averaged spike segments (on-line) of 17 patients, were correctly classified by means of NN. The sensitivity of the NN for spikes from unknown patients was 98%. The classification scheme enables an objective classification of (multi-) regional spikes for selective averaging and for studies dealing with syndrome classification.

Child↗
PubMed1996

A model of protein targeting mediated by immunophilins and other proteins that bind to hsp90 via tetratricopeptide repeat domains.

We have shown recently that the immunophilins CyP-40 and FKBP52/hsp56 bind to a common site on hsp90 and that they exist in separate heterocomplexes with the glucocorticoid receptor (GR). FKBP52/hsp56 binds to hsp90 via its tetratricopeptide repeat (TPR) domains, it is not required for GR.hsp90 heterocomplex assembly, and it is thought to play a role in targeted movement of the GR. In this work we examine the hsp90 binding of four proteins (FKBP52/hsp56, CyP-40, p50, Mas70p) thought to be involved in targeted protein trafficking. FKBP52/hsp56 and CyP-40 (each with three TPRs), localize to the nucleus and nucleoli, respectively, and form relatively weak complexes with hsp90 that are competed by a CyP-40 fragment containing its three TPRs. The p50 component of the Src.hsp90 and Raf.hsp90 heterocomplexes localizes to cytoskeletal fibers extending from the perinuclear region to the plasma membrane and forming a rim under the plasma membrane of endothelial cells. p50, Mas70p (seven TPRs), which is a receptor for mitochondrial import, and the p60 (six to eight TPRs) component of the steroid receptor.hsp90 heterocomplex assembly system bind very tightly to hsp90 in a manner that is not competed by the CyP-40 fragment. However, bacterially expressed p60 blocks the binding of p50, Mas70p, FKBP52/hsp56, and CyP-40 to purified hsp90. The data are consistent with binding of all of these proteins to a site on hsp90 that is a general TPR domain acceptor. Our localization and binding data are used to develop a model in which proteins that are chaperoned by hsp90 move as dynamic complexes to their cellular sites of action, with the TPR-containing protein participating in targeting the movement of the complexes.

Amino Acid Sequence↗
PubMed1996

Instantaneous frequency maps, dipole models and potential distributions of pattern reversal-evoked potential fields for correct recognition of stimulated hemiretinae.

Lateral hemifield pattern-reversal visual evoked potential (PVEP) field data were evaluated using potential distributions, dipole modelling and distributions of Hilbert transformation-based instantaneous frequency in order to determine the stimulated hemisphere. Twenty channel records were collected from 35 normal volunteers in two laboratories using similar stimulus conditions (11-20.5 degrees target, 60-75 min checks, 2/s reversal, 500 ms analysis epoch). P100 latency was determined in each average by the global field power maximum between 90 and 120 ms. Using the data from O1 and O2 at P100 latency, the stimulated hemisphere was identified by maximal potential or minimal instantaneous frequency on the stimulus-contralateral side, or, using the 20-electrodes data at P100 by the ipsilateral lateralization of the dipole model. Correct classification of the stimulated 70 hemiretinae was achieved by potential distribution in 44 cases, by dipole modelling in 54 cases and by instantaneous frequencies in 68 cases. Errors in the classification by potential distribution and dipole location were twice as frequent for decisions based on expected locations over the left than over the right hemisphere. This finding might be caused by the relatively larger size of the left occipital lobe. We conclude that a single value of instantaneous frequency which implies a massive data reduction can serve as a robust parameter for the characterization of the input conditions of hemifield PVEP (i.e. the stimulated hemiretina). It is more successful than potential distribution or dipole modelling, probably because instantaneous frequency incorporates considerably more information than the other two measures. It is suggested to explore instantaneous frequency as a parameter to recognize small retinal area stimuli in perimetry studies.

Adult↗
PubMed1996

[What needs following treatment have long-term schizophrenic patients? The problem of self- and external assessment of "needs"].

Needs for help and support were examined in 153 schizophrenic patients who had been being hospitalized for more than 6 months. In an operationalized and systematic way, needs as viewed by patients and their therapists were assessed using the Berliner Bedürfnis Inventar. In general as well as regarding single domains of life therapists stated significantly more needs than the patients; the agreement between patients' and therapists' views was very low. Frequency of needs as expressed by the patients was correlated with self-rated complaints, but not with observer ratings of psychopathology. Needs were mostly met by medical and social institutions according to the patients' statements. Patients reported more often than their therapists that adequate help and support was not provided in some areas despite an existing need. Clinical and research implications of the findings are discussed.

Female↗
PubMed1996

Laparoscopic Swenson's procedure in children.

The technique is described, and the experience gained with 7 laparoscopic sigmoid resections is reported. The approach resembles Swenson's technique with only the preparatory part performed laparoscopically. With the most recent procedures, the anaesthesia time of the laparoscopic procedure did not exceed that of the open technique. There were no serious complications or blood losses.

Adolescent↗
PubMed1996

Laparoscopic removal of Meckel's diverticula in children.

We report on 4 children where Meckel's diverticula (MD) were excised laparoscopically. In two of the children the finding of an MD was incidental and in two it was suspected preoperatively. In three of the patients the MD was ligated by means of an "endoloop" and could be removed in a similar manner to an appendix. In one patient the MD was resected by means of a stapler. No complications occurred. Subsequent histology confirmed the complete excision of the MD. Allowing for the size and shape of an MD, we prefer to excise it by means of an endoloop. An endoloop has the advantage that it can be used through a 5 mm trocar while a stapler has the disadvantage that it requires a larger 12 mm trocar and it leaves a foreign body, i.e. metal clips behind.

Adolescent↗
PubMed1996

Endorectal color Doppler imaging of primary and recurrent rectal wall tumors: preliminary experience.

OBJECTIVE: The purpose of our study was to assess whether color Doppler imaging is a useful adjunct to endorectal sonography in evaluating rectal wall neoplasms and in distinguishing recurrent or residual tumor from postoperative changes. MATERIALS AND METHODS: Thirty-two patients underwent endorectal sonography with color Doppler imaging for one of two indications: evaluation and staging of a suspected primary rectal wall cancer, or distinguishing tumor recurrence from postoperative scarring in patients with previously resected lesions. Rectal wall lesions were evaluated for hypervascularity, and their corresponding flow patterns were graded from 0 to 4. Local tumor staging with endorectal sonography and color Doppler imaging was performed before the results of pathological staging were available. RESULTS: Ninety-five percent of patients with malignant rectal wall tumors demonstrated hypervascularity during color Doppler imaging. In 61% of patients with rectal cancers, prominent perirectal vessels were identified supplying the tumor and were never identified in patients with benign lesions. Endorectal sonography alone correctly identified perirectal fat invasion with a 100% sensitivity and an 83% specificity. Color Doppler imaging during endorectal sonography correctly identified perirectal fat invasion with a sensitivity of 91% and a specificity of 83%. Of the 8 patients with previously resected lesions (five adenomas and three cancers), two patients had recurrent tumor, and both of these demonstrated grade 3 abnormality. Six patients with biopsy-proven fibrosis only had grades of 0 or 1. CONCLUSIONS: Both benign and malignant rectal wall tumors demonstrate abnormal intratumoral hypervascularity when seen with color Doppler imaging. Advanced rectal cancers (T3 or greater) are also associated with abnormal perirectal vascularity. Color Doppler imaging during endorectal sonography does not appear to improve discrimination of benign from T2 (or less) rectal wall cancers, nor does it appear to improve the ability to locally stage rectal wall cancers during endorectal sonography. However, endorectal sonography with color Doppler imaging may add significant information in distinguishing recurrent tumor from postsurgical scarring.

Female↗
PubMed1996

[Clinical characteristics of long-term hospitalized patients. Part I of the Berlin Deinstitutionalization Study].

The Berlin Deinstitutionalization Study investigates effects of the planned reduction of psychiatric hospital beds in Berlin prospectively. In the beginning cross-sectional survey all adult psychiatric patients from two and a half districts, who had been hospitalized for more than 6 months, were examined. The total sample was 422 patients. Treatment situation and needs for nursing care are reported. The primary diagnosis according to ICD-10 was organic disorder (incl. Korsakov's syndrome) in 70 patients and mental retardation in 61. Psychopathology and social disabilities were examined in 237 of the remaining 291 patients. On average, psychopathology and disabilities were moderate. A cluster analysis classified three groups. When patients should be discharged, special protective measures might be necessary only for the two smaller groups (together 31%).

Adolescent↗
PubMed1996

Effect of progressive systemic sclerosis on antral myoelectrical activity and gastric emptying.

In patients with progressive systemic sclerosis (PSS) suffering from chronic dyspepsia the stomach may be affected by this disease. The objective of this study was to investigate both antral myoelectrical activity and gastric emptying in PSS patients. Electrogastrography (EGG) was performed in 17 PSS patients (16 female, one male, median age 58 years, range 32-74 years) with chronic dyspepsia. After an overnight fast during one hour in the fasting and one hour in the fed state after ingestion of a liquid-solid test meal (370 kcal; liquid phase labeled with 0.5 mCi 99mTc-colloid) antral electrical activity was measured by one pair of electrodes sonographically placed on the skin overlying the gastric antrum. Several EGG parameters including dominant frequency (DF), percentages of DF in the normal range (2-4 cycles per minute [cpm]), bradygastria (< 2 cpm) and tachygastria (4-10 cpm), dominant frequency instability coefficient (DFIC), and postprandial to preprandial power ratio (PR) were calculated. The data were correlated to results obtained in 20 age- and gender-matched healthy subjects. In addition, the data were compared to gastric retention of the radionuclide at 60 min measured by simultaneous scintigraphy. The PSS patients did not reveal electrical disturbances. They even exhibited a significant postprandial decrease in DFIC, bradygastria, and tachygastria (ns) compared to healthy subjects. Over 50% of the PSS patients showed a delayed gastric emptying. However, EGG did not correlate to radioscintigraphy significantly. Our results reflect an absent relationship between antral myoelectrical activity in EGG and gastric emptying. Therefore, electrogastrography is unsuitable to assess gastric involvement in PSS.

Adult↗