Hippurs?uresynthese und Ausscheidung der Benzoes?ure beim Hunde

Zusammenfassung 1. Der Umfang der Hippurs?uresynthese ist nach Benzoes?urezufuhr relativ weit geringer beim Hunde (Carnivoren) als beim Herbivoren (Kaninchen, Hammel). Die Menge der freien Benzoes?ure ist im Urin meist gr?sser als die Menge der an Glycocoll gebundenen Benzoes?ure. 2. Durch Verabreichung gr?sserer Dosen Benzoes?ure (ca. 0,8 bis 1 g pro Kilo K?rpergewicht) gelingt es nicht beim Hunde, eine erhebliche Glycocollausfuhr zu erzeugen, da anscheinend beim Hunde intermedi?r das Glycocoll nicht die gleiche Rolle wie beim Herbivoren spielt, d. h. Vorstufe eines grossen Theiles der Harnstoffbildung ist. 3. Je h?her die dem Hundeorganismus zugeführte Menge Benzoes?ure ist, desto gr?sser ist das „Deficit der Benzoes?ureausfuhr“. 4. Dieses „Deficit der Benzoes?ureaufuhr“ beim Hunde erkl?rt sich durch das Auftreten eines stark reducirenden rechtsdrehenden K?rpers im Urin (Verbindung mit Benzoes?ure). Glucurons?ure ist im Hundeurin weder frei, noch durch Spaltung mit Schwefels?ure als gebunden sicher erweisbar. Die reducirende, optisch active Substanz geht nicht in das Alkoholextract des Urins. 5. Die Entgiftung der Benzoes?ure beim Hunde geschieht daher zum geringsten Theil durch Hippurs?urebildung, zum gr?ssten Theile durch Bindung mit jener nicht n?her bekannten Substanz. Ein nicht unbetr?chtlicher Theil der Benzoes?ure verl?sst als freie Benzoes?ure wieder den Organismus.     

Melatonin Profile in Marmots: The Influence of Catecholamines, Hibernation, and Light

The aim of this study was to determine the effects of circulating catecholamines and light on the daily melatonin rhythm in the marmot. Endogenous levels of circulating catecholamines and plasma melatonin were measured during arousal from hibernation in light and studies were performed on the circadian melatonin rhythm in two photoperiods (LD 4:20 and LD 8:16). In addition, studies were done on the capacity of broad-band white light at normal room intensities (32 muW/cm2 or 108 Ix) and of low-intensity monochromatic green light (500 nm; 1.4muW/cm2 or 3.1 Ix) to suppress high nocturnal melatonin levels. We conclude that high levels of plasma catecholamines that occur during arousal from hibernation do not influence the production and secretion of pineal melatonin. During the nocturnal portion of its light/dark cycle, the marmot plasma melatonin rhythm is suppressed by both white light and low-intensity green light.     

Indeterminate adnexal masses at ultrasound: effect of MRI imaging findings on diagnostic thinking and therapeutic decisions

Objective  

To determine the impact of MRI including DWI on therapeutic decision-making and costs in the work-up of patients with a indeterminate adnexal mass on ultrasound.     

Intra-operative femoral condylar stress during arthroscopy: an in vivo biomechanical assessment

Purpose

Excessive varus and valgus stress forces during arthroscopy might exceed minimal compressive strength of cancellous bone. In extreme cases, this could lead to post-arthroscopic osteonecrosis. It was our purpose to measure the valgus and varus stress forces during arthroscopy and draw conclusions on the development of osteonecrosis.

Methods

On 24 consecutive patients undergoing arthroscopy, the maximum varus and valgus stress forces (N) were measured in vivo using a strain gauge mounted to a leg holder. The forces (N) and contact stresses (kPa) on the femoral condyles were calculated based on the measured acting lateral force at the femur fixation based on the lever principle.

Results

The maximum contact stress during varus on the medial condyle was significantly lower in patients with intact meniscus (mean?±?standard error of the mean: 243?±?29?kPa) than in patients with meniscus-deficient knees (520?±?61?kPa; P?<?0.01). A similar finding was obtained for the maximum contact stress during valgus on the lateral condyle: 630?±?72?kPa in patients with intact meniscus compared to 2,173?±?159?kPa in patients with meniscus-deficient knees (P?<?0.01). In 19 patients (79%), the maximum contact stress was higher during valgus than during varus. The maximum contact stress on the lateral condyle during valgus was significantly higher for more experienced surgeons (P?=?0.01).

Conclusion

The maximum contact stresses in knees with intact menisci did not exceed the critical threshold of the compressive strength in cancellous bone. However, the maximum contact stresses in meniscus-deficient knees were frequently higher than the threshold. However, these stresses were much lower than those during daily activities and therefore unlikely to lead to post-arthroscopic osteonecrosis.

Level of evidence

Diagnostic study, Level II.     

Spindle cell oncocytoma of the adenohypophysis: report of a case with a 16-year follow-up

Spindle cell oncocytoma (SCO) is a recently described, rare neoplasm of the anterior pituitary. Clinically and radiologically simulating a non-functioning macroadenoma, its eponymous fusiform cells display a non-epithelial phenotype with conspicuous cytoplasmic accumulation of mitochondria. We report a case of SCO retrospectively identified in a biopsy specimen 16 years after transsphenoidal operation of a 48-year-old woman. Presenting symptoms were adynamia and transient decrease of visual acuity. Neuroimaging showed an isointense, enhancing, sellar-centered mass 1.8 cm in diameter without evidence of invasive growth. No postoperative adjuvant therapy was administered. The patient was left with panhypopituitarism, yet no recurrence was seen during follow-up. Initially diagnosed as a null cell adenoma of oncocytic type, repeat immunohistochemistry showed the characteristic coexpression of S100 protein, vimentin, and epithelial membrane antigen. Oncocytic granula stained intensely with antimitochondrial antibody 113-1, and were negative with the lysosomal marker CD68. Anterior pituitary hormones tested negative, and there was no evidence of neuroendocrine differentiation using antibodies to synaptophysin and chromogranin. Few cells stained for glial fibrillary acidic protein (GFAP). SCO has been proposed to represent a neoplasm of folliculo-stellate cells (FSCs). While the dynamic properties of the latter are incompletely characterized, and indeed no specific marker allows for their identification, overlapping features of SCO with look alikes, in particular pituicytoma, point to FSCs being a potential adult stem cell. The favorable outcome of the present case further argues for SCO to be considered a low-grade neoplasm. Moderate tumor size, lack of invasiveness, and low proliferation rate are likely predictors of benign behavior.     

Role of cholecystokinin in the regulation of gastric emptying and pancreatic enzyme secretion in humans. Studies with the cholecystokinin-receptor antagonist loxiglumide

The role of cholecystokinin (CCK) in the regulation of gastric emptying and pancreatic enzyme secretion was evaluated by infusing the CCK-receptor antagonist loxiglumide. Gastric emptying rates and pancreatic secretory outputs were measured in five healthy volunteers by the double-indicator perfusion technique using a multiple-lumen tube in the duodenum. Placebo or loxiglumide (22 mumol.kg-1.h-1) was infused throughout each experiment. Five hundred-milliliter liquid intragastric meals of (a) fat, protein, and glucose (Ensure; Abbott, Chicago, IL); (b) glucose, 20 g/dL; and (c) guar gum, 1.1 g/dL, were given in random order. In addition, the effect of a physiologic CCK-8 dose (20 pmol.kg-1.h-1) after an intragastric 500-mL saline meal (0.154 mol/L) was tested. Intravenous CCK-8 induced a marked retardation of the gastric emptying rate of the saline solution (P less than 0.05) while stimulating pancreatic secretory outputs; both effects were completely abolished by the infusion of loxiglumide. Loxiglumide markedly accelerated the gastric emptying rates (by approximately 40%) and simultaneously diminished lipase (by approximately 75%) and trypsin (by approximately 50%) outputs of both the mixed meal (P less than 0.01) and the pure glucose meal (P less than 0.05). Additional experiments using gamma camera scintigraphy confirmed the accelerating effect of loxiglumide on gastric emptying of the mixed meal (P less than 0.01). The gastric emptying rate of the guar meal, which did not release CCK, was not influenced by the infusion of loxiglumide. Loxiglumide distinctly augmented plasma CCK levels after the mixed (2.6 times) and the pure glucose (2.1 times) meals while markedly reducing (approximately 76%) pancreatic polypeptide release (P less than 0.02). It is concluded that endogeneous CCK exerts a major role in the regulation of both gastric liquid emptying and pancreatic secretion in humans.