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Biomedical subjects

K Richter

Publications and source records attributed to K Richter.

At least 181 records · Page 10Linked to original sources
PubMed1995

[The bioequivalence of metoclopramide in two tablet formulations].

An investigation on the bioavailability of a tablet with 10 mg metoclopramide-HCl (CAS 363-62-5) Cerucal was performed in a two-way cross-over study with 12 volunteers. Metoclopramide was determined in serum by HPLC. The relative bioavailability (mean and nonparametric 95% confidence interval) with respect to a reference preparation was 0.95 (95% CI 0.88-1.02) for AUC and 0.92 (95% CI 0.79-1.07) for Cmax. A positive decision for bioequivalence was derived from the usual confidence intervals for both parameters. The tmax-values did not differ significantly. Statistical evaluation of all parameters revealed bioequivalence between the two preparations.

Adult↗
PubMed1995

[Static to sequential plan analysis].

The method of Plan Analysis helps for a better understanding of the interactional engagement of the client within the client-therapist relationship. In spite of this interactional conceptualization of the method, plan analysis produces only a statical diagnosis of interpersonal intentions and plans. In order to realize a dynamical analysis of the client-therapist relationship, the method has to be modified. The steps of this modification will be explained. The result is an idiographic, discovery oriented strategy, called "Sequential Plan Analysis" (SPA), which can be used to do single case analysis of psychotherapy processes. SPA produces sequential patterns of interactional plans (nominal data) as well as quantitative time series.

Adult↗
PubMed1994

Elucidation of the structure of talinolol metabolites in man. Determination of talinolol and hydroxylated talinolol metabolites in urine and analysis of talinolol in serum.

The objective of this study was to determine the structure of talinolol metabolites formed and the amounts excreted in urine. Talinolol metabolites in urine were identified by comparing their HPLC retention times and their GC-MS profile with those of previously characterized reference compounds. The metabolites were quantified by HPLC with a normal-phase silica column, a single chloroform extraction and UV detection. Less than 1% of an administered dose was found in urine as hydroxylated talinolol. Other metabolites could be excluded. A sensitive method to determine talinolol in serum and a simple method for analysis of talinolol in urine are described. These methods were found to be precise and accurate for the measurement of talinolol in samples obtained from patients during chronic talinolol treatment as well as from healthy volunteers after a single dose of talinolol.

Adrenergic beta-Antagonists↗
PubMed1994

Oculocutaneous albinism, immunodeficiency, hematological disorders, and minor anomalies: a new autosomal recessive syndrome?

We report on 2 related children, a boy and a girl, from a large Turkish clan. Their parents are both first cousins and have several common ancestors. Both children have tyrosinase-positive oculocutaneous albinism, recurrent bacterial infections, granulocytopenia, intermittent thrombopenia, and microcephaly, a protruding midface, rough and projecting hair, and mild mental retardation. Chromosomes are normal. Metabolic disorders were excluded. None of 14 well-known types of albinism, including Hermansky-Pudlak syndrome and Chediak-Higashi syndrome, nor any other genetic syndrome, characterizes our patients sufficiently. Thus, this combination of symptoms is considered a new autosomal recessive syndrome.

Abnormalities, Multiple↗
PubMed1994

High-density morphologies of ice in high-pressure frozen biological specimens.

Mouse liver tissue was rapidly cooled by high-pressure freezing at a nominal pressure of 2100 bar. Ultrathin cryosections were examined at 110 K with a cryoelectron microscope and the state of water was studied on micrographs and electron diffraction patterns. The results are compared with those from liver specimens cryofixed at ambient pressure by plunge freezing. The high-pressure frozen specimens contained crystalline frozen regions as well as areas which were vitreous. The spot diffraction patterns from crystalline regions are found to differ from those known for hexagonal ice. The comparison with powder diffraction data reveals the presence of the high-density morphologies Ice II and Ice III. Vitreous areas of biological samples frozen at ambient pressure are optically denser than areas where the water crystallised as cubic or hexagonal ice. However, on micrographs from high-pressure frozen samples, no significant contrast is found. This observation is explained by the higher specific mass of high-pressure ice compared to Ice I, an interpretation which requires a higher specific mass for high-pressure vitreous water compared to vitreous water produced at ambient pressure. The larger diffuse first ring of the diffraction pattern from high-pressure vitreous water confirms this argument.

Animals↗
PubMed1994

Cutting artefacts on ultrathin cryosections of biological bulk specimens.

Cryoelectron microscopy of ultrathin cyrosections permits study of the ultrastructure of cells in the hydrated state. However, cryosectioning deforms the cut volume as the sections are compressed in the cutting direction while their thickness is increased with respect to the cutting feed. The compression has been measured on the elliptical deformation of lipid droplets in liver cells. It is about 40% at 48 degrees cutting angle while it is reduced to 30% at 38 degrees. The section deformation involves the underlying ultrastructure as far as the specimen is deformable. Three deformation modes are discussed. Crystalline ice is broken into chips which are tilted and pressed out of the section plane to account for the section deformation. Within one chip, the ultrastructure of the ice is preserved. In contrast, hydrated catalase crystals deform plastically. Cutting shortens the crystal distances the same amount as cryosections are compressed. Distances in hexagonal DNA crystals are also influenced by cutting since the spots of diffraction patterns are blurred in the cutting direction. However, the crystal spacing is not shortened in the cutting direction. The crystal apparently reorganizes during cutting deformation.

Animals↗
PubMed1994

Paracetamol absorption from different sites in the human small intestine.

Site-specificity in the small intestinal absorption of paracetamol was investigated using a segmental intestinal steady state perfusion technique (triple-lumen tubing system) combined with simultaneous measurements of serum drug concentrations. Dissolved paracetamol was perfused over 160 min into different parts of the small intestine (65-210 cm beyond the teeth). Each of the four healthy subjects was studied twice with a proximal and a more distal site of perfusion. Serum drug concentrations were similar after proximal and distal perfusions. Mean drug absorption rates calculated from intestinal aspirate concentrations were similar in both parts of the intestine--proximal: 869 micrograms 30 cm-1 min-1 (95% CI: 659-1079) vs distal: 941 micrograms 30 cm-1 min-1 (794-1088). The absorption rate was related directly to the amount of paracetamol perfused per unit time as well as to the rate of transmucosal water fluxes.

Acetaminophen↗
PubMed1994

A cryoglue to mount vitreous biological specimens for cryoultramicrotomy at 110K.

Mixtures of ethanol, 2-propanol and 2-butanol can be used as a cryoglue to mount vitrified biological specimens for ultrathin cryosectioning. Brought directly from room temperature to a cutting support at 140 K in the cold chamber of a cryoultramicrotome, these alcohols stiffen to a viscous and gluey consistency allowing the attachment or embedding of a vitreous biological sample. The mass hardens at lower temperatures fixing the sample well for microtomy. With ethanol: 2-propanol (2:3), samples are applied at 140 K and ultrathin cutting can be done at 115 K.

1-Propanol↗
PubMed1994

Structure of intracellular mature vaccinia virus observed by cryoelectron microscopy.

Intracellular mature vaccinia virus, also called intracellular naked virus, and its core envelope have been observed in their native, unfixed, unstained, hydrated states by cryoelectron microscopy of vitrified samples. The virion appears as a smooth rounded rectangle of ca. 350 by 270 nm. The core seems homogeneous and is surrounded by a 30-nm-thick surface domain delimited by membranes. We show that surface tubules and most likely also the characteristic dumbbell-shaped core with the lateral bodies which are generally observed in negatively stained or conventionally embedded samples are preparation artifacts.

Cryoultramicrotomy↗
PubMed1994

Internal migration in Thailand.

"Internal migration of the population of Thailand involves a number of distinct forms of movement. Three forms are identified in this research: single-move, seasonal and repeat. The first can be treated as long-term migration while the latter two are more temporary. All forms are characterized by different geographical flows and different selectivity patterns. Long-term migration is highly selective of young adults, females and the more highly educated. It is most likely to occur between urban areas or from rural to urban areas. Temporary migration mainly involves movement back and forth between urban and rural places and is most likely to be engaged in by those with a medium level of education."

Age Factors↗
PubMed1994

Technique for detecting and evaluating breast lesions.

A sonographic method is described that provides additional information concerning ultrasonic tissue properties. It allows simplified interpretation and eventually might permit automatization. In this technique a totally reflecting plate is used as an indicator for presence of breast lesions because such lesions cause changes of reflectivity, attenuation, and velocity when exposed to ultrasound beams. Twenty-seven benign lesions and 33 malignancies were examined with this method.

Breast Diseases↗
PubMed1994

The impact of child care on fertility in urban Thailand.

Women's labor force participation in Thailand, particularly in the modern sector, recently has increased in conjunction with rapid declines in fertility. This paper examines whether a relationship exists between child care considerations and fertility decision making among Bangkok women. Although the two-child family has become the norm in recent years, and although most respondents said that ideally they would like to have two children, a high proportion of women surveyed said they planned to only have one child. Women's work status and type of employment is found to strongly affect the likelihood of having a second birth: those who work at jobs that not only are low-paying but are located in a formal setting are least likely to have a second child. The type of child care for the first child also has an impact: those whose first child is in a less preferred situation are less likely to have a second. Variables measuring the need for and type of child care are found to have greater consequences for fertility than do usual measures of socioeconomic status.

Adolescent↗