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Biomedical subjects

L Fahrenkrug

Publications and source records attributed to L Fahrenkrug.

14 recordsLinked to original sources
PubMed1991

Expression of preproVIP-derived peptides in the human gastrointestinal tract: a biochemical and immunocytochemical study.

In order to study biosynthetic processing of the precursor for vasoactive intestinal peptide (preproVIP) in the human gut we have developed antisera against the five functional domains of the precursor molecule: preproVIP 22-79, peptide histidine methionine (PHM), preproVIP 111-122, VIP and preproVIP 156-170. The antisera were used to quantify and characterize VIP-precursor peptides by radioimmunoassay (RIA) together with high-pressure liquid Uchromatography (HPLC) and to examine their cellular localization and colocalization by immunocytochemistry. All five peptides were expressed but not in equimolar amounts as expected from the amino acid sequence of the precursor. However, the ratios between them were fairly constant throughout the gastrointestinal tract. The only exceptions were the lower concentrations of PHM and preproVIP 111-122 in the gastric antrum which could be explained by the presence of PHV (the C-terminally extended form of PHM which includes preproVIP 111-122) in large concentrations in this region. It was also found that the C-terminal lysine residue of preproVIP is not removed during processing. Immunocytochemically all preproVIP-derived peptides were shown in neuronal elements. They had a similar distribution throughout the gut suggesting coexistence, a finding which was supported by doublestaining. The findings indicate that differences in the posttranslational processing of preproVIP exist in subpopulations of neurons in the human gut.

Chromatography, High Pressure Liquid↗
PubMed1991

Intestinal and renal calcium-binding protein in rats with experimental short bowel syndrome.

Intestinal calcium-binding protein (calbindin-D9K) and renal calcium-binding protein (calbindin-D28K) levels were measured by enzyme-linked immunoadsorbent assays in rats with short bowel syndrome induced by resection of about 85% of the small intestine. Rats with short bowel syndrome had significantly lower mucosal concentrations of calbindin-D9K (P less than 0.001) and a parallel reduction of both intestinal calcium absorption (P less than 0.001) and p-1,25-dihydroxyvitamin D (P less than 0.01) in spite of a general hypertrophy of the duodenal mucosa. Interestingly, the renal concentration of calbindin-D28K was significantly elevated (P less than 0.05) in rats with short bowel syndrome, a change apparently related to factors independent of vitamin D.

Animals↗
PubMed1991

Massive hematuria due to iliac artery-ureteral fistula. Case report.

Massive hematuria in a 73-year-old man, who 17 years previously had undergone aorto-iliac-femoral thrombendarterectomy, was found to originate from an iliac artery-ureteral fistula due to a false aneurysm. Fistula formation should be kept in mind when investigating such hematuria in patients with a history of vascular surgery in the iliac segment.

Aged↗
PubMed1986

Cecal angiodysplasia localized by 99mtechnetium blood-pool scintigraphy and specimen venography.

Angiodysplasia of the right colon may be difficult to diagnose. The usual methods of choice, selective abdominal angiography and colonoscopy, may be impracticable or fail. When bleeding occurs, 99mtechnetium blood-pool scintigraphy is a simple and reliable method of localizing vessel leakage. We present a case of an 84-year-old woman with severely bleeding angiodysplasia, where the source of bleeding was localized by means of scintigraphy using 99mTc in vivo labeled red blood cells. After right hemicolectomy, the angiodysplastic lesion was confirmed by specimen venography utilizing a barium gelatin mixture.

Aged↗
PubMed1986

The value of dynamic ultrasound scanning in Crohn's disease.

In a prospective, blinded study we investigated 30 patients with Crohn's disease (CD) and 27 normal controls by means of dynamic grey-scale ultrasound scan. Within a few weeks the patients were also examined by radiography of the small bowel. Of the 30 patients, 21 had CD lesion of the small bowel as judged by radiography. A target lesion at the ultrasound scan indicating thickened bowel wall was seen in 15 CD patients, of which 14 showed radiographic signs of CD in the ileum and/or right side of the large bowel, whereas one had normal radiographic findings. Seven patients out of 15 without sonographic changes had radiographic signs of CD. The patients with discrepancy between the two examinations could not be clinically characterized as an entity. None of the 27 normal controls showed signs of intestinal disease at the ultrasound examination. We conclude that dynamic grey-scale ultrasound examination is a new tool in depicting the CD lesion, but it does not seem to be able to replace the radiographic examination. However, it may find a place in the follow-up study of patients with known CD, thereby avoiding repeated radiographic examinations. Furthermore, the possibility of diagnosing abscesses and fistulae by sonography is well known and has relevance in CD.

Adolescent↗
PubMed1981

Vasoactive intestinal polypeptide (VIP) in the male genitourinary tract: concentration and motor effect.

Vasoactive intestinal polypeptide (VIP) has previously been shown in nerves of the male and female genitourinary tract, appearing to innervate vascular and nonvascular smooth and epithelial cells. In the present study the concentration of VIP in tissue extracts of different parts of the male genitourinary tract from cat and man was determined by radioimmunoassay. In addition, the effect of VIP on the contractility of the smooth muscle from the cat genitourinary tract was investigated in vitro. The tissue concentrations of VIP were generally higher in cat than in man. In both species high concentrations were found in the vas deferens, bladder, urethra and prostate, In concentration from 3 x 10(-8) to 6 x 10(-7) mol x 1-1, VIP inhibited in a concentration-dependent manner the muscle contractions in specimens from all regions examined, i.e., the vas deferens, ureter, corpus of the bladder, and urethra. The data indicate that VIP might play a physiologic role in the local nervous control of the smooth muscle activity in the male genitourinary tract.

Adult↗
PubMed1980

VIP occurs in intrathyroidal nerves and stimulates thyroid hormone secretion.

Vasoactive intestinal polypeptide (VIP) is known to have powerful effects on the secretion from several endocrine and exocrine glands, and occurs in nerves with a ubiquitous distribution in the body. This infers that neuronal VIP may be a regulator of such secretion, and there is evidence that it is involved in the regulation of exocrine pancreatic function. Previous studies have shown that adrenergic and cholinergic nerves participate in the regulation of thyroid hormone secretion. We describe here combined immunohistochemical and immunochemical studies which show that the thyroid of several species is supplied with VIP-containing nerve fibres that surround blood vessels and run between and along thyroid follicles and that in the mouse neuronal VIP participates in the regulation of thyroid hormone secretion through a mechanism that is mediated by cyclic AMP.

Animals↗