Biomedical subjects

C Haake

Publications and source records attributed to C Haake.

4 recordsLinked to original sources

PubMed2001

Determination of phytosiderophores by anion-exchange chromatography with pulsed amperometric detection.

Phytosiderophores of the mugineic acid family are separated by anion-exchange HPLC using NaOH gradient elution. Separation of mugineic acid (MA), 2'-deoxymugineic acid (DMA), 3-hydroxymugineic acid (HMA) and 3-epi-hydroxymugineic acid (epi-HMA) is obtained within 15 min. Detection of the underivatised phytosiderophores is performed using pulsed amperometric detection (PAD) at pH 13. The sensitivity of the detection increases in the order DMA < MA < HMA < epi-HMA and respective detection limits of 5 microM (DMA), 1 microM (MA) and < 0.5 microM (HMA, epi-HMA) are achieved. PAD is discussed in comparison with the well-established fluorimetric detection method after post-column derivatisation with ortho-phthaldialdehyde. The main advantage of PAD is the simplicity of the method (no derivatisation) and the high sensitivity for hydroxylated mugineic acids. The method is used for the determination of phytosiderophores in root washings of iron-deficient and non-deficient wheat and barley plants.

Anion Exchange Resins↗

PubMed1993

A new fine needle for easier, single handed, ultrasound-guided biopsies, requiring less advancing forces into solid organs.

A fine punch needle with a new bevelled geometry for easy, single-handed, ultrasound-guided biopsies is presented. The needle requires a significantly lower advancing force compared with the commonly used punch needles of the Menghini type. Since, therefore, our needle penetrates the organs to be investigated easier, it enables the puncture of easily movable (stomach, gut) and/or solid organs (kidney) with the yield of sufficiently long punch cylinders. The first 196 biopsies were well tolerated and histological diagnosis could be made in 94% of the cases.

Biomechanical Phenomena↗

PubMed1991

Minor malformations, hyperactivity, and learning disabilities.

Standardized minor malformation scores have been reported to predict and identify children with attentional problems and hyperactivity. The reason why this marker works for only a subset of children with attention deficit hyperactivity disorder remains unclear. The dysmorphology scores on all children presenting for a multidisciplinary team evaluation of developmental disorders were examined for diagnostic correlations after children with chromosomal disorders and recognized dysmorphic syndromes were excluded. For 1233 subjects, the mean minor malformation score was 2.94 (SD = 2.05). A significant association between minor malformation scores and IQ (mean = 80.95, SD = 23.67) was accounted for by the group with IQs greater than 100 exhibiting the higher dysmorphology scores. An analysis of variance revealed no significant association between minor malformation scores and hyperactivity or attention deficit disorder. Indeed, the presence of an attention deficit disorder yielded lower mean dysmorphology scores. When the minor malformation scores were compared for those subgroups of children with and without specific learning disabilities, the learning-disabled subjects had significantly higher dysmorphology scores. Minor dysmorphic features do not relate to the presence or absence of attentional problems or hyperactivity in referred children. Rather they appear to characterize that subpopulation of children with attention deficit disorder and learning disabilities as well as a group of learning-disabled children without attentional disorders.

Adolescent↗

PubMed1989

The learning-disabled medical student.

Developmental pediatricians are being consulted by medical school promotion committees with regard to the course of action to be taken with learning-disabled medical students experiencing academic difficulties. Faculty attitude, a difficulty understanding the nature of learning disabilities, appears to be a major contributor to poor medical school performance on the part of learning-disabled adults. Utilizing the sequential-simultaneous information processing model as a simplified introduction to learning disability patterns, the authors argue that recommending intensive remediation of rote spelling and writing skills in students engaged in graduate education represents both a waste of time and a further emotional trauma to these young professionals.

Achievement↗