Search PubMed⌕ Search

Biomedical subjects

D Richter

Publications and source records attributed to D Richter.

At least 163 records · Page 9Linked to original sources
PubMed1996

Lacto-N-fucopentaose III (Lewis x), a target of the antibody response in mice vaccinated with irradiated cercariae of Schistosoma mansoni.

Carbohydrates on soluble egg antigens are major epitopes for the antibody responses of patients and mice infected with Schistosoma mansoni. Recently, protective sera of mice vaccinated with irradiated cercariae were shown to recognize carbohydrate epitopes on schistosomal glutathione S-transferase. The present study demonstrates that carbohydrate epitopes are major targets of sera from C57BL/6J and CBA/J mice vaccinated with 15- or 50-kilorad-irradiated cercariae of S. mansoni. Antibody titers to carbohydrate epitopes increased with the number of vaccinations and were considerably higher in C57BL/6J mice than in CBA/J mice. The specificity of this anticarbohydrate response was determined by measuring antibody binding to defined oligosaccharide residues known to be present on the parasite. A predominant target of the humoral anticarbohydrate response of vaccinated mice was lacto-N-fucopentaose III, a molecule relevant for cell trafficking. We observed no binding to its nonfucosylated homolog, lacto-N-neotetraose, or to oligosaccharides present on keyhole limpet hemocyanin. The strongest antibody response to lacto-N-fucopentaose III was observed for C57BL/6J and CBA/J mice repeatedly vaccinated with 15-kilorad-irradiated cercariae, which also achieve the highest levels of protection. Immunoglobulin M was the predominant antibody class binding to lacto-N-fucopentaose III. We conclude that in the irradiated-cercariae vaccine model, C57BL/6J and CBA/J mice produce anticarbohydrate antibodies against various stages of S. mansoni and that the oligosaccharide lacto-N-fucopentaose III is one target of this response. Lacto-N-fucopentaose III and its specific antibodies may profoundly affect host resistance and parasite homing.

Animals↗
PubMed1996

Positive somatostatin receptor scintigraphy correlates with the presence of somatostatin receptor subtype 2.

Somatostatin receptor scintigraphy (SRS) is positive in approximately 75% of all patients with neuroendocrine gastroenteropancreatic tumours. This study aimed to identify specific somatostatin receptor (sstr) subtypes, which are responsible for the in vivo binding of the widely used somatostatin analogue, octreotide in human neuroendocrine gastroenteropancreatic tumours. Twelve patients underwent SRS with radiolabelled octreotide. After surgical resection, tumour tissues were analysed in vitro for somatostatin and octreotide binding sites by autoradiography. In addition, for the first time, sstr subtype mRNA expression was examined by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Tumour tissues from all SRS positive patients were positive by autoradiography. Semiquantitative RT-PCR revealed most prominently sstr2 expression in scintigraphically positive tumours. Two SRS negative tumours contained in vitro octreotide binding sites as well as high levels of sstr1 and sstr2 mRNAs. Positive SRS is mainly due to sstr2. sstr1, 3, 4, and probably 5 are less important for in vivo octreotide binding. False negative scintigraphic results seem to be influenced by factors independent of the expression of specific sstr.

Adult↗
PubMed1996

[Elastic intramedullary nailing--a concept for treatment of unstable forearm fractures in childhood].

The standard treatment for forearm fractures in children is usually conservative. Unstable fractures of the proximal parts of the forearm often show poor results after nonoperative management, so that these fractures require surgical intervention. We report about 20 children ranging in age from 6 to 14 years who were treated by elastic intramedullary nailing. Ten patients were treated by intramedullary pinning immediately after their accident; 10 required intramedullary nailing after failure of the conservative treatment and redislocations of their fractures. At the time of follow-up 6 months later, functional results were "excellent" in 16 children, "good" in 3 children and "fair" in one child. There were no serious complications apart from the occurrence of one delayed union. According to these results intramedullary nailing can be recommended for the treatment of unstable fractures of the proximal and middle parts of the forearm in children.

Adolescent↗
PubMed1996

[Elbow arthrodesis and its alternative].

Significant functional impairment, increasing pain or joint infection are the indications for arthrodesis of the elbow joint. Six patients underwent a compression arthrodesis with internal and external fixation and an additional bone graft in our institution between 1987 and 1993. Out of this series only one patient developed a non-union due to a fall on the extremity. In a series of nine patients treated with external fixation alone between 1978 and 1987, four patients developed a non-union. Unlike other joints, there is no optimal position for arthrodesis of the elbow and the functional deficit cannot be compensated by the other joints of the upper extremity. Therefore, it should be useful to know if an interposition arthroplasty is possible. With this technique a joint infection can be healed. Ten patients treated with this technique between 1987 and 1993 had no recurrent infection. Two patients had instability. The best results were achieved in post-traumatic joint stiffness. Permanent instability and post-traumatic arthritis are indications for an allo-arthroplasty. Contraindications are a previous joint infection and intensive bone loss, as well as ipsilateral shoulder ankylosis and neuropathic joint disorders. In younger patients, resection arthroplasty is better due to a high loosening rate of the prostheses.

Adolescent↗
PubMed1996

[Determinants of patient structure according to the psychiatry personnel decree. On the problem of comparing psychiatric clinics].

In Germany psychiatric hospitals are increasingly facing external comparisons with other psychiatric hospitals and departments. The focus of these comparisons often is the constitution of inpatients according to the "Decree of Psychiatric Personnel" (Psychiatrie-Personalverordnung). This report evaluates factors that influence patient categorisation into the treatment categories of the mentioned decree. The analysis yields three sociodemographic factors as significant predictors of a categorisation to the intense-treatment category A2: 1. compulsory admission into the hospital, 2. first ever admission, 3. urban place of residence. Major methodical problems of patient categorisation into categories of the decree are elucidated. The validity of the current approach that chooses four selected qualifying days per year as the basis of representation of the annual patient population in psychiatric hospitals and departments is questioned.

Adult↗
PubMed1996

[The limits of it all. Critique of holistic concepts in nursing science].

Limits of the Whole. A critique of holistic concepts in nursing science. Nursing theories, almost without exception, are geared towards the so-called holistic paradigm in order to differentiate themselves from the deficits of a modern, functionally orientated medicine. This paper evaluates the holistic paradigm as a sound basis for nursing science. A comparison with developments in other scientific disciplines which have already moved away from holistic approaches shows that nursing science departs from these tendencies in allied disciplines. An empirical investigation of nurses' subjective theories about their patients shows that the holistic approach is also unsatisfactory for practical purposes. It is recommended to give up the holistic paradigm in nursing science.

Attitude of Health Personnel↗
PubMed1996

[Ultrasound follow-up of callus distraction--an alternative to roentgen diagnosis?].

In a prospective study 20 patients were regularly monitored with sonograms in four planes and radiographs during distraction osteogenesis of the lower limb. Ultrasonography is more sensitive than radiography in identifying new bone formations during distraction, in measuring the length of the distraction gap, and in detecting early bone healing complications, and can therefore reduce the need for radiographs. Radiographs are necessary to assess the time of fixator removal and the axis of the leg.

Bone Lengthening↗
PubMed1995

Effect of hypoosmolality on the abundance, poly(A) tail length and axonal targeting of arginine vasopressin and oxytocin mRNAs in rat hypothalamic magnocellular neurons.

Arginine vasopressin (AVP) and oxytocin (OT) mRNAs are targeted to the axonal compartment of rat hypothalamic magnocellular neurons. Salt-loading results in a considerable rise in hypothalamic and axonal AVP mRNA but only a moderate increase for axonal OT mRNA. Here we report that hypoosmolality gives rise to a rapid decrease of axonal AVP encoding transcripts to undetectable levels after 2 weeks. The levels of OT mRNA in the axonal compartment did not change significantly. In the hypothalamus the mRNA for AVP also decreased. The size of the poly(A) tract of AVP encoding transcripts appeared to be strictly correlated with plasma osmolality. In contrast, the amount and size of OT encoding mRNAs were only moderately or not influenced by hypoosmolar stimuli.

Animals↗
PubMed1995

Teleost isotocin receptor: structure, functional expression, mRNA distribution and phylogeny.

A cDNA encoding a receptor for the oxytocin-related peptide isotocin has been identified by screening a lambda gt11 library constructed from poly(A)+ RNA of the hypothalamic region of the teleost Catostomus commersoni. The probe used was obtained by PCR amplification of white sucker genomic DNA using degenerate primers based on conserved sequences in the mammalian receptor counterparts. The full-length cDNA specifies a polypeptide of 390 amino acid residues that displays the typical hydrophobicity profile of a seven transmembrane domain receptor and which exhibits greatest similarity to mammalian oxytocin receptors. Oocytes that express the cloned receptor respond to the application of isotocin by an induction of membrane chloride currents indicating that it is coupled to the inositol phosphate/calcium pathway. The isotocin receptor (ITR) can also be activated by vasotocin, mesotocin, oxytocin and Arg-vasopressin, although these have lower potencies than isotocin. ITR-encoding mRNA has been detected in brain, intestine, bladder, skeletal muscle, lateral line, gills and kidney indicating that this receptor may mediate a variety of physiological functions.

Amino Acid Sequence↗
PubMed1995

Cloning, functional expression and mRNA distribution of an inwardly rectifying potassium channel protein.

In GH3/B6 cells at least two different inward K+ currents are observed that are regulated by thyrotropin-releasing hormone and somatostatin, respectively. Using a polymerase chain reaction based approach a cDNA was isolated and functionally expressed in human embryonic kidney cells that encodes an inward rectifier K+ channel, rIRK3, with a predicted molecular mass of 49.7 kDa. Corresponding transcripts of 2.6 kb have been detected in rat brain, pituitary and GH3/B6 cells. In situ hybridization revealed that rIRK3 mRNA is distributed throughout the brain and occurs predominantly in the piriform cortex, indusium griseum, supraoptic nucleus, facial nucleus and cerebellar Purkinje cells.

Amino Acid Sequence↗
PubMed1995

Differential subcellular mRNA targeting: deletion of a single nucleotide prevents the transport to axons but not to dendrites of rat hypothalamic magnocellular neurons.

It has previously been shown that mRNA encoding the arginine vasopressin (AVP) precursor is targeted to axons of rat magnocellular neurons of the hypothalamo-neurohypophyseal tract. In the homozygous Brattle-boro rat, which has a G nucleotide deletion in the coding region of the AVP gene, no such targeting is observed although the gene is transcribed. RNase protection and heteroduplex analyses demonstrate that, in heterozygous animals, which express both alleles of the AVP gene, the wild-type but not the mutant transcript is subject to axonal compartmentation. In contrast, wild-type and mutant AVP mRNAs are present in dendrites. These data suggest the existence of different mechanisms for mRNA targeting to the two subcellular compartments. Axonal mRNA localization appears to take place after protein synthesis; the mutant transcript is not available for axonal targeting because it lacks a stop codon preventing its release from ribosomes. Dendritic compartmentation, on the other hand, is likely to precede translation and, thus, would be unable to discriminate between the two mRNAs.

Animals↗
PubMed1995

Adaptive Silicon Monochromators for High-Power Insertion Devices. Tests at CHESS, ESRF and HASYLAB.

X-ray wigglers which produce tens of kilowatts of photon power within the white beam will soon become available at third-generation sources of synchrotron radiation. Insertion devices that produce several kilowatts already exist and we have used those at CHESS, ESRF and HASYLAB to test adaptive 111 silicon water-jet-cooled monochromators at up to 2 kW total incident beam power. This development from earlier work at the Brookhaven National Synchrotron Light Source (NSLS) uses the pressure in the water coolant to provide active compensation of the strain field in the thermal footprint, nulling its effect to within residual variations in Bragg angle of only a few arc s. The design is robust, vacuum compatible and uses no moving mechanical parts.

Journal Article↗
PubMed1995

[Epitheloid osteosarcoma. Differential diagnostic problems].

The case of a 23-year-old female patient suffering from a rare variety of osteosarcoma of the distal femur with epithelial differentiation and only traces of osteoid is reported. The tumour cells reacted strongly to antibodies against vimentin. Metastases were found in the fifth rib and the right kidney. There was no response to chemotherapy. One year after implantation of a tumour prosthesis of the knee a thigh amputation was necessary because of a local failure. The patient died 2.5 years after the tumour had initially been diagnosed. Other reports of this rare type of epitheloid osteosarcoma illustrate the difficulties involved in reaching a correct diagnosis. This tumour can be mistaken for a skeletal metastasis of an epithelial tumour.

Adult↗
PubMed1995

The irradiated cercariae vaccine model: looking on the bright side of radiation.

Schistosomes infect between 200 and 300 million people at any one time. A major strategy to reduce the impact of schistosomiasis on human health is the development of a defined antigen vaccine. Protective immunity induced in mice by irradiated cercariae may serve as a model for the development of a vaccine. In such vaccinated mice, worm burdens resulting from challenge infection can be reduced by more than 90% compared to non-vaccinated mice. During the past three decades, the irradiated-carcariae vaccine model has been dissected in the detail in order to determine factors that may be relevant to vaccination, such as the participating immune compartments, the site and kinetics of the immune response, and the antigens recognized. In this review, Dania Richter, Donald A. Harn and Franz-Rainer Matuschka highlight the research on the vaccine model, focusing on the murine model using gamma-irradiated cercariae of Schistosoma mansoni.

Journal Article↗
PubMed1995

A novel G protein-coupled receptor mediating both vasopressin- and oxytocin-like functions of Lys-conopressin in Lymnaea stagnalis.

We have cloned a receptor, named LSCPR, for vasopressin-related Lys-conopressin in Lymnaea stagnalis. Lys-conopressin evokes Ca(2+)-dependent Cl- currents in Xenopus oocytes injected with LSCPR cRNA. Expression of LSCPR mRNA was detected in central neurons and peripheral muscles associated with reproduction. Upon application of Lys-conopressin, both neurons and muscle cells depolarize owing to an enhancement of voltage-dependent Ca2+ currents and start firing action potentials. Some neurons coexpress LSCPR and Lys-conopressin, suggesting an autotransmitter-like function for this peptide. Lys-conopressin also induces a depolarizing response in LSCPR-expressing neuroendocrine cells that control carbohydrate metabolism. Thus, in addition to oxytocin-like reproductive functions, LSCPR mediates vasopressin-like metabolic functions of Lys-conopressin as well.

Amino Acid Sequence↗