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Biomedical subjects

M Knapp

Publications and source records attributed to M Knapp.

At least 199 records · Page 11Linked to original sources
PubMed1990

[Impedance of the respiratory tract of healthy newborn infants--studies using the polyfrequency oscillation method].

Resistance and reactance of the respiratory tract of 40 healthy newborn were measured by means of the polyfrequent oscillation method. Mean resistance had frequency-dependent values between 20.91 and 9.63 cm H2O per litre per second and mean reactance between -29.11 and -3.81 cm H2O/1/s. The resistance--but not the reactance--was found to depend on the body length and the body weight of the infants.

Airway Resistance↗
PubMed1989

Isotretinoin embryopathy--a continuing problem.

First trimester exposure to isotretinoin is associated with an estimated 20% risk of major fetal malformations. Product labeling in force up to August 1988 included a statement that the drug is contraindicated in pregnancy and suggested procedures for prescribing physicians to follow to prevent inadvertent first trimester exposure to the product. This limited educational intervention did not prevent the continued occurrence of isotretinoin-related birth defects. The effectiveness of recent changes in the package labeling in preventing such birth defects remains to be demonstrated. Two infants with major birth defects associated with first trimester exposure to isotretinoin (Accutane, Roche Laboratories) were reported to the New Jersey Birth Defects Registry within 6 months. Stimulated by these reports, we sought additional cases in New Jersey and found three. We here describe these five cases of isotretinoin embryopathy, including available information on the circumstances which led to maternal use of isotretinoin during the first trimester of pregnancy. In response to a preliminary report of these cases and to investigations by epidemiologists at the U.S. Food and Drug Administration (FDA), the manufacturer altered the package labeling. The revised product information includes a more prominent "contraindication and warning" section and a new "patient information/consent" section. The effectiveness of this educational intervention should be evaluated.

Abnormalities, Drug-Induced↗
PubMed1989

Investigation of genetic markers in patients with Crohn's disease and ulcerative colitis.

Inflammatory bowel diseases (IBD) as Crohn's disease (CD) and ulcerative colitis (UC) are believed to have a genetic basis. Additional factors are supposed to promote the development of IBD. However, apart from a few reports of HLA associations which await confirmation by other groups strong associations to (a) particular genetic marker(s) are still lacking. We here report on previously unobserved associations of CD to MNSS and UC to the immunoglobulin heavy chain allotype Gm 1,-2,10. We suggest that these factors play a role in a wider spectrum of genetic markers for the development of IBD.

Acid Phosphatase↗
PubMed1988

Prevalence of coeliac disease in diabetic children and adolescents. A multicentre study.

Screening for coeliac disease (CD) with serum antigliadin antibodies (AGA) was performed in 1032 diabetic children and adolescents. In 8 children CD had been diagnosed before study entry. Of the remaining 1024 children, 33 had an elevated AGA titre in the first serum sample. On follow-up an elevated AGA titre was confirmed in only 17 of 31 patients. Nine of the repeatedly positive patients underwent jejunal biopsy, and CD was diagnosed in two asymptomatic patients; both were positive for IgG- and IgA-AGA. Among 10 AGA-positive patients in whom biopsies could not be performed, only 1 showed IgA-AGA and thus carried a high risk for CD. From our results we estimate a prevalence of CD in Swiss and German diabetic children between 1.1% and 1.3%. False-positive AGA titres occurred significantly more often in patients with diabetes duration of less than 1 year. AGA testing reached a specificity of 99% if performed at least 1 year after the onset of diabetes. Children suffering from both diabetes and CD showed a diabetes manifestation at a significantly younger age than non-coeliac patients, whereas CD tended to be diagnosed at a remarkably late age.

Adolescent↗
PubMed1988

Early ontogeny of the central benzodiazepine receptor in human embryos and fetuses.

The early ontogeny of the central benzodiazepine receptor (BZR) was investigated in human embryos and fetuses between 7 and 26 weeks of gestation. Brain tissue was gained from terminated pregnancies or spontaneous abortions. Binding studies, which were performed with 3H-flunitrazepam (FNZ), revealed that specific benzodiazepine binding is already detectable at an embryonal age of 7 weeks post conceptionem. Binding at this early stage can be displaced potently by clonazepam and the inverse agonist beta-CCE. Additionally, 3H-FNZ binding is enhanced by GABA. Thus, benzodiazepine binding is of the central type. Receptor density increases steeply in whole brain between weeks 8 and 11 of gestation. In frontal cortex receptor density increases gradually between weeks 12 and 26 of gestation. No specific fetal disease entity (including trisomy 21) was consistently associated with exceptionally high or low Bmax-values.

Brain↗
PubMed1988

Relationships between drug regime and histology of rectal mucosa in Crohn's disease.

In the scope of the ECCDS, testing the efficacy of prednisolone and/or sulfasalazine in Crohn's disease, the relationships between drug regime and histology of rectal mucosa were studied. Rectal biopsies, gained at start and after termination of treatment were available in 57 patients. Additionally, biopsies of 20 normal controls were studied. The biopsies, cut completely in serial sections, were investigated by quantitative histological methods. The data were evaluated by multivariate discriminant analyses. The nearest approach of histologic pattern to normal was found after combined treatment with prednisolone and sulfasalazine, followed by prednisolone monotherapy. The effect of sulfasalazine as monotherapy was poor. The degree of normalisation in histologic pattern agrees very well with the CDAI in our subsets. Overall, effective therapy was reflected in histology of rectal mucosa by a decrease of acute inflammatory alterations and an increase of mononuclear infiltration. Only minor individual effects of the various drug regimes were found.

Crohn Disease↗
PubMed1988

Relationships between blood chemistry and histology of the rectal mucosa in Crohn's disease.

In the scope of the ECCDS, established to test the efficacy of prednisolone and/or sulfasalazine in Crohn's disease, the relationships of blood chemistry and CDAI to histology of rectal mucosa were studied in 115 patients by means of univariate and multivariate statistical analyses. Laboratory and histologic markers of inflammation tend to be correlated. But these correlations are definitively weak. Thus, the predictive value of histology for blood chemistry or CDAI is very low. Laboratory indices and CDAI are relatively inaccurate means of assessing disease severity at tissue level and vice versa.

Alpha-Globulins↗
PubMed1987

Effects of filaggrin breakdown products on the growth and maturation of keratinocytes.

Filaggrin is degraded to amino acids in the stratum corneum. We tested the hypothesis that the resulting high concentrations of amino acids might be involved in the control of keratinocyte maturation. An amino acid mixture, with the composition of the filaggrin breakdown products, inhibited the growth of cultured human keratinocytes at 0.1 M. Inhibition of protein synthesis was progressive with time. After 24-h exposure, 50% inhibition occurred at 0.3-0.4 M amino acids. When the cultures were incubated with the amino acids for 7 days, the concentration giving half-inhibition was reduced to 0.2 M. No change was observed in the pattern of keratin synthesis, although synthesis of protein with Mr of 36,000 was disproportionately inhibited. It is concluded that filaggrin breakdown products are not involved in the control of keratinocyte differentiation.

Amino Acids↗
PubMed1987

Selective elimination of mRNAs in vivo: complementary oligodeoxynucleotides promote RNA degradation by an RNase H-like activity.

Oligodeoxynucleotides lead to translation arrest of complementary mRNAs in the wheat germ translation system by a degradation of the mRNA. In an attempt to develop an effective reverse genetic approach in vivo, we demonstrate that injection of short (15- to 30-nucleotide) oligonucleotides into Xenopus oocytes leads to complete degradation of both injected and endogenous mRNAs by means of an RNase H-like activity.

Animals↗
PubMed1986

Low back pain and x-ray films of the lumbar spine: a prospective study in primary care.

We prospectively studied 96 men with low back pain to evaluate the association of x-ray findings with clinical diagnosis, treatment, functional outcome, and satisfaction with care. Degenerative joint disease (DJD) was the most common radiologic finding (70%). Making the diagnosis of spinal DJD has little effect on patient management, but patients with x-ray evidence of DJD were three times more likely than those with normal films to receive nonsteroidal anti-inflammatory drugs other than aspirin. Furthermore, patients given a "diagnostic label" of DJD were more likely to express satisfaction with medical care and less likely to seek care elsewhere than patients with similar x-ray results who were given nonspecific diagnoses. These factors will need to be considered in arriving at an estimate of the net benefits of x-ray examination of the lumbar spine.

Adult↗