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Biomedical subjects

D Richter

Publications and source records attributed to D Richter.

At least 73 records · Page 4Linked to original sources
PubMed2001

Physician/patient differences in the perception of asthma: impact on everyday life and level of the asthma control in Croatia.

The aim of the study was to compare physician/patient differences in the perception of asthma. The data were obtained by questionnaires from 156 physicians and 148 asthmatics in four urban regions in Croatia. On a "bad day", 62% of physicians and 16% of patients perceived respiratory symptoms with statistically significant difference. The patients described asthma impact in terms of reduced daily activities and experienced emotional problems. Asthma was estimated as controlled in 28% of adults and 49% of children, nevertheless, 45% of adults and 22% of children reported respiratory symptoms. The patients seem to be satisfied with asthma control that does not correspond to suppression of symptoms, whereas physicians neglect patients' emotional problems and asthma impact on everyday life. The differences in the perception of asthma may reflect differences in beliefs about health. Physicians see health as an absence of symptoms, whereas patients regard being healthy as "being able".

Activities of Daily Living↗
PubMed2000

The calcium-independent receptor for alpha-latrotoxin from human and rodent brains interacts with members of the ProSAP/SSTRIP/Shank family of multidomain proteins.

Subtypes of the calcium-independent receptors for alpha-latrotoxin (CIRL1-3) define a distinct subgroup within the large family of the seven-transmembrane region cell surface receptors. The physiological function of CIRLs is unknown because neither extracellular ligands nor intracellular coupling proteins (G-proteins) have been identified. Using yeast two-hybrid screening, we identified a novel interaction between the C termini of CIRL1 and -2 and the PSD-95/discs large/ZO-1 (PDZ) domain of a recently discovered multidomain protein family (ProSAP/SSTRIP/Shank) present in human and rat brain. In vitro, CIRL1 and CIRL2 interacted strongly with the PDZ domain of ProSAP1. The specificity of this interaction has been verified by in vivo experiments using solubilized rat brain membrane fractions and ProSAP1 antibodies; only CIRL1, but not CIRL2, was co-immunoprecipitated with ProSAP1. In situ hybridization revealed that ProSAP1 and CIRL1 are co-expressed in the cortex, hippocampus, and cerebellum. Colocalization was also observed at the subcellular level, as both CIRL1 and ProSAP1 are enriched in the postsynaptic density fraction from rat brain. Expression of all three CIRL isoforms is highly regulated during postnatal brain development, with CIRL3 exhibiting its highest expression levels immediately after birth, followed by CIRL2 and finally CIRL1 in aged rats.

Amino Acid Sequence↗
PubMed2000

Development of an automated diode-laser-based multicomponent gas sensor.

The implementation and application of a portable fiber-coupled trace-gas sensor for the detection of several trace gases, including CO2, CH4, and H2CO, are reported. This particular sensor is based on a cw fiber-amplified near-infrared (distributed Bragg reflector) diode laser and an external cavity diode laser that are frequency converted in a periodically poled lithium niobate crystal to the mid-IR spectroscopic fingerprint region (3.3-4.4 micrometers). A continuous absorption spectrum of CH4 and H2CO from 3.37 to 3.10 micrometers with a spectral resolution of 40 MHz (approximately 0.0013 cm-1) demonstrated the spectral performance that can be achieved by means of automated wavelength tuning and phase matching with stepper motor control. Autonomous long-term detection of ambient CO2 and CH4 over a 3- and 7-day period was also demonstrated.

Automation↗
PubMed2000

Origin of dynamic heterogeneities in miscible polymer blends: A quasielastic neutron scattering study

In order to investigate the origin of the often invoked nanoheterogeneities in miscible polymer blends, we have performed quasielastic neutron scattering experiments on the component dynamics within the miscible polymer blend polyisoprene/polyvinyl ether including the pure components as a reference. We find that the apparent local heterogeneities observed by spectroscopic techniques originate from the chain specific crossover properties between entropy driven and local chain dynamics and are, thus, a purely dynamical phenomenon.

Journal Article↗
PubMed2000

Membrane decoration by amphiphilic block copolymers in bicontinuous microemulsions.

The effect of various amphiphilic block copolymers of different molar masses on the structure and phase behavior of ternary amphiphilic systems (water, oil, and nonionic surfactant) is investigated. Small amounts of PEP-PEO block copolymer lead to a dramatic increase in the volumes of oil and water, which can be solubilized in a bicontinuous microemulsion. High-precision neutron scattering experiments with a sophisticated contrast variation technique demonstrate that the polymers form uniformly distributed mushroom conformations on the surfactant membrane. Based on these observations, we propose a universal mechanism for the swelling behavior, which is due to the variation of the membrane curvature elasticity.

Cell Membrane↗
PubMed2000

Two trans-acting rat-brain proteins, MARTA1 and MARTA2, interact specifically with the dendritic targeting element in MAP2 mRNAs.

Different isoforms of the microtubule-associated protein 2 (MAP2) are somatodendritic components of neurons that seem to regulate the stability of the dendritic cytoskeleton. MAP2 localization into dendrites appears to be a complex multicausal mechanism that involves the specific recruitment of MAP2 mRNAs into dendritic compartments. Recently, we have functionally characterized a 640-nucleotide dendritic targeting element (DTE) in the 3' untranslated region (3' UTR) of MAP2 transcripts that mediates extrasomatic mRNA localization in primary neurons (Blichenberg et al. , 1999). In analogy to molecular mechanisms regulating cytoplasmic RNA translocation in other cell systems, we propose that, in vivo, the cis-acting MAP2-DTE interacts with specific protein factors present in neurons. To identify putative trans-acting DTE-binding proteins, we performed in vitro ultraviolet crosslinking assays. Using this experimental system, two 90-kDa and 65-kDa MAP2-RNA trans-acting proteins, MARTA1 and MARTA2, were identified in rat-brain extracts. Both MARTAs bind with high affinity to the MAP2-DTE, but not to other investigated regions of MAP2 transcripts or the somatically restricted alpha-tubulin mRNA. Moreover, MARTA1 and MARTA2 do not bind significantly to other dendritically localized transcripts encoding vasopressin and arg3.1, nor to a dendritic trafficking element from the mRNA encoding the alpha-subunit of the Ca(2+)/calmodulin-dependent protein kinase II. Binding of MARTA1 and MARTA2 to the MAP2-DTE occurs with an affinity in the nanomolar range. Whereas MARTA1 is clearly detectable in crude lysates, cytosolic and ribosomal salt-wash fractions, and in nuclear extracts, MARTA2 is preferentially found in the ribosomal salt-wash preparation. Neither MARTA is restricted to rat brain, and both are present in a number of other rat tissues. Thus, both proteins may be involved in a variety of nuclear and cytoplasmic events that regulate RNA metabolism in different cell types.

3' Untranslated Regions↗
PubMed2000

Interaction of the somatostatin receptor subtype 1 with the human homolog of the Shk1 kinase-binding protein from yeast.

Interaction between the C terminus of a G-protein-coupled receptor and intracellular constituents may represent a crucial step in regulating signal transduction. To identify potential interacting candidates the C terminus of the somatostatin receptor subtype 1 was used as bait in a yeast two hybrid screen of a human brain cDNA library. We identified the human Skb1 sequence (Skb1Hs) as interacting protein, which is homologous to the yeast protein known Skb1 to down-regulate mitosis in Schizosaccharomyces pombe via binding to the Shk1 protein kinase; the latter is a homolog to the mammalian p21(cdc42/Rac)-activated protein kinases. Interaction required almost the entire C terminus of the somatostatin receptor subtype 1 including the conserved NPXXY motif of transmembrane region seven; in the case of the Skb1Hs most of the N terminus and an S-adenosylmethionine binding domain were mandatory, whereas the C terminus was not essential. Interaction was verified by coexpression experiments in human embryonic kidney cells. As revealed by immunocytochemical analysis Skb1Hs expressed alone aggregates in large cytosolic clusters. When coexpressed, receptor subtype 1 and Skb1Hs were colocalized at the cell surface; these cells showed a strong increase in somatostatin binding compared with cells expressing the receptor only. This may suggest that Skb1Hs acts like a chaperone by correctly targeting the receptor to the cell surface.

Amino Acid Sequence↗
PubMed2000

Compact CH4 sensor based on difference frequency mixing of diode lasers in quasi-phasematched LiNbO3.

A compact, portable and robust room temperature CH4 sensor is reported. By difference frequency mixing a 500 mW alpha-DFB diode laser at 1066 nm and an erbium-doped fiber amplified 1574 nm DFB diode laser in periodically poled lithium niobate up to 7 (mu)W of narrowband radiation at 3.3 microns is generated. Real-time monitoring of CH4 over a 7 day period using direct absorption in an open-path multipass cell (L = 36 m) demonstrates a detection precision of +/- 14 ppb.

Calibration↗
PubMed2000

FasL:Fas ratio--a prognostic factor in breast carcinomas.

Programmed cell death (apoptosis) is primarily mediated by Fas ligand (FasL; CD95L) and the Fas receptor (Fas; CD95). In this study, FasL was detected by immunohistochemical analysis in 85% of breast carcinomas and 14% of fibroadenomas randomly chosen, indicating that high expression of FasL might play a role in tumor pathology. FasL and Fas levels as well as FasL:Fas ratios were further ascertained in 215 human breast tumors, including 199 invasive ductal carcinomas, by real-time quantitative reverse transcription-PCR and compared with expression levels and ratios found in 25 normal human tissues, in 37 fibroadenomas, and in 5 normal breast tissues. Among breast carcinomas, high FasL mRNA expression seems to be positively correlated with histological grading (n = 212; P<0.0001). A ratio of FasL:Fas mRNA transcripts >1 is found to be significantly associated with decreased patient's disease-free survival (n = 211; P<0.03) and increased mortality (n = 211; P = 0.19). A FasL:Fas ratio >1 is related to tumor progression scored by histological grading (n = 212; P<0.02). The selection process leading to highly aggressive breast tumor variants might be enhanced by FasL-mediated tumor fratricide, eventually a possible target for novel therapeutic strategies.

Adolescent↗
PubMed2000

Changes of the T-wave amplitude and angle: an early marker of altered ventricular repolarization in hypertension.

BACKGROUND: The heterogeneity of ventricular repolarization is an important proarrhythmic factor. QT dispersion has been proposed to reflect the inhomogeneity of ventricular repolarization, but a poor reproducibility limits its clinical applicability. Reliable noninvasive methods to quantify abnormalities in ventricular repolarization are still lacking. The T-loop morphology analysis is a novel method aimed at quantifying ventricular repolarization. HYPOTHESIS: To test the ability of the T-loop morphology analysis to discriminate between hypertensive patients and healthy subjects, 105 hypertensive patients (mean age 63.6 +/- 12.3 years) and 110 healthy controls (mean age 49.7 +/- 14.3 years) were evaluated. METHODS: The maximum QT interval (QT maximum), the minimum QT interval (QT minimum), and their difference (QT dispersion) were calculated from a digitally recorded 12-lead electrocardiogram (ECG) in both study groups. X, Y, and Z leads were reconstructed from the 12-lead ECG, and the amplitude of the maximum T vector (T amplitude) and the angle between the maximum T vector and X axis (T angle) were calculated from the projection of the T loop in the frontal plane. RESULTS: T amplitude (p < 0.001), T angle (p = 0.05), and QT dispersion (p = 0.04) were significantly different between hypertensive patients and controls, while QT maximum (p = 0.14) and QT minimum (p = 0.35) did not differ between the groups. T amplitude was the only marker which differed between hypertensive patients without ECG criteria for left ventricular hypertrophy and controls (p = 0.002). CONCLUSIONS: T-loop features and particularly T amplitude are significantly different between hypertensive patients and healthy controls and may serve as early markers of repolarization abnormalities in a hypertensive population.

Action Potentials↗
PubMed2000

[Benign tenosynovial giant cell tumor in the region of the upper ankle joint. A rare differential diagnosis of a soft tissue tumor of the foot].

The giant cell synovioma is a benign neoplasia classically located in the fingers. It mostly rises from tendon sheaths, sometimes from the synovia. Other locations than the fingers are rare. Making a differential diagnosis to lipomas, gangliomas or even malignant soft tissue tumors can be very difficult especially in rare locations. We report the case of a 21 years old man suffering from a giant cell synovioma in the area of the right ankle joint. The clinical, radiological and patho-morphological findings are documented. The tumor was excised totally, other foci were not found. The problems of making the right diagnosis are described.

Adult↗
PubMed2000

[Need for psychosocial nursing care in a psychogeriatric nursing home].

The aim of this study is to analyze the dimensions of psychosocial nursing requirements in a psychogeriatric nursing home. In addition to biographical and anamnestical data of nursing home residents, the psychosocial nursing requirements are measured with the Nurses' Observations Scale for Geriatric Patients (NOSGER). Data are compared with patients of a psychogeriatric department of a state psychiatric hospital. Results show that psychogeriatric nursing home residents have at least as much psychosocial restrictions as acutely mentally ill patients in the psychiatric hospital. In some dimensions of the NOSGER (memory, social behavior) residents show even higher scores than the control group. By analyzing the rate of residents and psychogeriatric patients who score above the cut-off points given by the NOSGER developers, it is shown that the rate of residents with psychosocial nursing requirements is at least as high as in the control group. Concerning the NOSGER dimensions Instrumental Activities of Daily Living and Social Behavior, the rate of nursing home residents above the cut-off points is significantly greater than the rate of the acute psychogeriatric patients. It is concluded that budgets of psychogeriatric nursing homes must be able to finance qualified psychiatric personnel to meet the residents' special psychosocial requirements adequately.

Activities of Daily Living↗
PubMed2000

Relative incompetence of european rabbits for Lyme disease spirochaetes.

To determine whether rabbits may serve as reservoir hosts for Lyme disease spirochaetes in Europe, we compared their competence as hosts for Borrelia afzelii, one of the most prevalent European spirochaetal variants, with that of the Mongolian jird. To infect rabbits or jirds, at least 3 nymphal or adult Ixodes ricinus ticks infected with spirochaetes fed to repletion on each animal. Whereas jirds readily acquired tick-borne Lyme disease spirochaetes and subsequently infected vector ticks, rabbits exposed to tick-borne spirochaetes rarely became infectious to ticks. Only the rabbit that was infectious to ticks developed an antibody response. To the extent that I. ricinus ticks feed on European rabbits, these mammals may be zooprophylactic by diverting vector ticks from more suitable reservoir competent hosts.

Animals↗
PubMed2000

A study of body weight concerns and weight control practices of 4th and 7th grade adolescents.

OBJECTIVE: The purpose of this study was to assess grade, race, socioeconomic status and gender differences in perceptions of body size, weight concerns, and weight control practices between 4th and 7th grade students in South Carolina. DESIGN: Two random samples, consisting of a total of 1,597 children (53.1% white, 51.97% female, 44.9% 4th graders) participated in two questionnaire surveys. Both surveys included a series of seven female and seven male body size drawings, body image and weight concern questions, and questions pertaining to weight control practices. Responses to the questionnaire were analyzed using chi-square analysis and the General Linear Model. RESULTS: Using socioeconomic status (SES), race, gender, and grade as independent variables, differences in ideal adult body size, opposite gender ideal adult body size, weight concerns, perceptions of family/peer weight concerns, perceptions of own body size and weight control practices were studied. Analyses revealed that 4th grade males select a larger ideal adult body size and opposite gender ideal adult body size when compared to 7th grade males (p < 0.0001 and p = 0.0078, respectively). Fourth grade females indicated less personal concern about their weight than 7th grade females (p = 0.0009). Fourth graders also perceived less family/peer concern about weight than 7th graders (p = 0.0027) and 7th graders described themselves as being more overweight than 4th graders (p = 0.0039). Blacks selected a significantly larger body size than white children for ideal adult (p = 0.0287) and ideal opposite gender adult body size (p < 0.0001 for males, p = 0.0030 for females). Blacks also perceived less personal and family/peer concern about weight when compared to whites (p = 0.0083). More whites reported that they were trying to lose weight, as compared to blacks (p = 0.0010). Males also selected significantly larger body size silhouettes than females for ideal adult body size (p = 0.0012). Males expressed less personal concern about weight (p < 0.0001), perceived less family/peer concern about weight (p < 0.0001), and were less likely than females to be engaged in weight loss (p < 0.0001). Females in the high SES category selected a significantly smaller ideal male adult body size than females in the low SES group (p = 0.0124) and more females in the high SES category were trying to lose weight when compared to females in the low SES group (p = 0.0055). CONCLUSION: This study indicates that early in a child's sociocultural development, grade level, gender, race, and SES are influential in the perception of ideal adult body size and opposite gender ideal adult body size. These factors are also influential in determining concerns about weight and weight control practices. The findings of this study support the need to begin health and wellness education efforts early in childhood while taking into account racial, gender, age, and SES disparities. This knowledge can also be useful in targeting interventions for both obesity and eating disorders.

Adolescent↗
PubMed2000

Open trial of psychodynamic psychotherapy for panic disorder: a pilot study.

OBJECTIVE: This report contains preliminary data from an open trial of brief psychodynamic psychotherapy for panic disorder. METHOD: Fourteen patients with primary DSM-IV panic disorder completed a 24-session, twice-weekly course of psychodynamic psychotherapy. Other psychiatric treatment was not permitted throughout the 12-week treatment period and the 6-month follow-up. Symptoms were assessed at baseline, treatment termination, and 6-month posttermination follow-up (40 weeks). RESULTS: Statistically significant, clinically meaningful improvements appeared in panic, depression, anxiety, and functional impairment both at treatment termination and at 6-month follow-up. CONCLUSIONS: Psychodynamic monotherapy can be used successfully to retain and treat patients with panic disorder. Psychodynamic interventions warrant further study for patients with panic disorder.

Adult↗
PubMed2000

Dual regulation of somatostatin receptor subtype 1 gene expression by pit-1 in anterior pituitary GH3 cells.

Somatostatin represents a major release inhibiting factor for hypophyseal hormones and mediates its action via five receptor subtypes, sst1-sst5, that are all present in the anterior pituitary. The pituitary specific transcription factor Pit-1 is essential for the pituitary development and pituitary-specific gene expression. Here the transcriptional regulation of the sst1 gene, which contains putative Pit-1-binding sites, was studied in anterior pituitary GH3 cells. We found that a fragment of 2 kb suffices to drive the expression of a reporter gene specifically in this cell line. Positive and negative cis-regulatory elements contributed to the promoter activity. Among these elements two functional binding sites for Pit-1 were identified. While the proximal site mediated transcriptional activation, the distal site attenuated transcription of reporter gene constructs. Mutations of the proximal Pit-1 site prevented expression of the reporter gene. Targeting Pit-1 mRNA by antisense oligonucleotides caused inhibition of transcription of reporter gene constructs containing the proximal Pit-1-binding site. Moreover, the expression of the endogenous sst1 gene in GH3 anterior pituitary cells was blocked. This resulted in reduced sst1 levels at the plasma membrane. Reduced sst1 levels were associated with a diminished antisecretory response to the sst1-specific agonist CH-275 and somatostatin. These results demonstrate the importance of Pit-1 for the expression of the sst1 gene, which hence is placed under common genetic control with the genes for hypophysiotropic hormones and the gene for the receptor of GH-releasing hormone.

Animals↗
PubMed2000

Absolute quantification of human chorionic gonadotropin-beta mRNA with TaqMan detection. 4.

We describe a reverse transcriptase-polymerase chain reaction (RT-PCR) for determination of human chorionic gonadotropin-beta (HCG beta) mRNA copies using the TaqMan system. To evaluate our quantitative assay, we analyzed HCG beta transcripts of all protein coding genes (HCG beta 5, 3, 8, and 7) in human RNA panels of different normal tissues and in glycodelin-A-stimulated trophoblast cell cultures. Absolute quantification using HCG beta TaqMan probe was found to be highly reproducible. Our study of RNA panels confirms recently published results that expression of HCG beta transcripts is a common feature of a great variety of different normal tissues. High levels of HCG beta mRNAs (> 1,000 molecules per 200 ng RNA) were detected in placenta, uterus, and testis. An increase of HCG beta mRNA expression (1.7-fold) was detected at 150 micrograms/mL glycodelin-A treatment in trophoblast cell culture. Time-dependence study showed that the increase in HCG beta mRNA level was evident at 60 min after glycodelin-A treatment. In summary, we have developed a highly sensitive one-tube, one-enzyme quantitative RT-PCR system that is time-saving and avoids postamplification procedures.

Adolescent↗