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Biomedical subjects

C Holtz

Publications and source records attributed to C Holtz.

9 recordsLinked to original sources
PubMed2000

Eight novel mutations and consequences on mRNA and protein level in pyruvate kinase-deficient patients with nonspherocytic hemolytic anemia.

Pyruvate kinase (PK) deficiency (PKD) is an autosomal recessive disorder with the typical manifestation of nonspherocytic hemolytic anemia. We analyzed the mutant enzymes of 10 unrelated patients with PKD, whose symptoms ranged from a mild, chronic hemolytic anemia to a severe anemia, by sequence analysis for the presence of alterations in the PKLR gene. In all cases the patients were shown to be compound heterozygous. Eight novel mutations were identified: 458T-->C (Ile153Thr), 656T-->C (Ile219Thr), 877G-->A (Asp293Asn), 991G-->A (Asp331Asn), 1055C-->A (Ala352Asp), 1483G-->A (Ala495Thr), 1649A-->T (Asp550Val), and 183-184ins16bp. This 16 bp duplication produces a frameshift and subsequent stop codon resulting in a drastically reduced mRNA level, and probably in an unstable gene product. Surprisingly, the existence of M2-type PK could be demonstrated in the patient's red blood cells. The study of different polymorphic sites revealed, with one exception, a strict linkage of the 1705C, 1738T, IVS5(+51)T, T(10) polymorphisms and the presence of 14 ATT repeats in intron 11. Our analyses show the consequences of a distorted structure on enzyme function and we discuss the correlations between the mutations identified and the parameters indicative for enzyme function.

Alleles↗
PubMed1999

Childhood obesity.

Childhood obesity has become one of the more alarming nutritional problems plaguing the American population, with estimates as high as 25% of all children being obese. Aside from obesity's associated risks, there are psychosocial and emotional burdens carried by obese children as well. Clinicians are encountering many of these children in their clinics everyday for other reasons and yet are failing to address the issue of obesity. The problem is not so much that physicians are not recognizing it, but rather that they are ignoring it, especially if the parent or child is unaware that there is a problem. Unfortunately, much controversy exists regarding the treatment of childhood obesity. This article attempts to sort through the myriad issues surrounding childhood obesity and to dispel some of the rumors and myths surrounding this subject.

Adolescent↗
PubMed1991

Production and properties of xylanases from thermophilic actinomycetes.

30 strains of xylanolytic thermophilic actinomycetes were isolated from composted grass and cattle manure and identified as members of the genera Thermomonospora, Saccharomonospora, Microbispora, Streptomyces and Actinomadura. Screening of these strains for extracellular xylanase indicated that strains of Saccharomonospora and Microbispora generally were poor xylanase producers (0.5-1.5 U/ml) whereas relatively high activities were observed in cultures of Streptomyces and Actinomadura (4-12 U/ml). A preliminary characterization of the enzymes of strains of the latter genera suggested that xylanases of all the strains of Actinomadura exhibited higher thermostabilities than those of Streptomyces. To evaluate the potential of thermophilic Actinomadura for industrial applications, xylanases of three strains were studied in more detail. The highest activity levels for xylanases were observed in cultures grown on xylan and wheat bran. The optimal pH and temperature for xylanase activities ranged from 6.0 to 7.0 and 70 to 80 degrees C. The enzymes exhibited considerable thermostability at their optimum temperature. The half-lives at 75 degrees C were in the range from 6.5 to 17 h. Hydrolysis of xylan by extracellular xylanases yielded xylobiose, xylose and arabinose as principal products. Estimated by the amount of reducing sugars liberated the degree of hydrolysis was 55 to 65%. Complete utilization of xylan is presumably achieved by beta-xylosidase activities which could be shown to be largely cell-associated in the 3 Actinomadura strains.

Actinomycetales↗
PubMedDate not supplied

Remifentanil in the horse: identification and detection of its major urinary metabolite.

Remifentanil (4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic acid methyl ester) is a mu-opioid receptor agonist with considerable abuse potential in racing horses. The identification of its major equine urinary metabolite, 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, an ester hydrolysis product of remifentanil is reported. Administration of remifentanil HCl (5 mg, intravenous) produced clear-cut locomotor responses, establishing the clinical efficacy of this dose. ELISA analysis of postadministration urine samples readily detected fentanyl equivalents in these samples. Mass spectrometric analysis, using solid-phase extraction and trimethylsilyl (TMS) derivatization, showed the urine samples contained parent remifentanil in low concentrations, peaking at 1 h. More significantly, a major peak was identified as representing 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, arising from ester hydrolysis of remifentanil. This metabolite reached its maximal urinary concentrations at 1 h and was present at up to 10-fold greater concentrations than parent remifentanil. Base hydrolysis of remifentanil yielded a carboxylic acid with the same mass spectral characteristics as those of the equine metabolite. In summary, these data indicate that remifentanil administration results in the appearance of readily detectable amounts of 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid in urine. On this basis, screening and confirmation tests for this equine urinary metabolite should be optimized for forensic control of remifentanil.

Analgesics, Opioid↗
PubMedDate not supplied

The culturally diverse student: a model for empowerment.

The student who is at a disadvantage due to race, educational background, or cultural background is often unsuccessful in higher education. Specific programs designed to assist the culturally diverse student can make a significant difference in the successful completion of a program of nursing and passing of the National Council Licensure Examination (NCLEX). The authors discuss a model that assists culturally diverse students' success in a program of nursing.

Cultural Characteristics↗