Seasonal changes in morphology and function of the gastrointestinal tract of free-living alpine marmots ( Marmota marmota).

The gastrointestinal tracts of 76 free-living alpine marmots ( Marmota marmota) shot during a population control program in Switzerland were collected and analysed for patterns of change in morphology and function over the period from emergence from hibernation in April to just before re-entry into hibernation in September. Between first emergence and mid-summer (July) the fresh tissue mass of the stomach increased by 105%, the small intestine by 259% (among the largest recorded for a mammal), caecum by 185%, proximal colon by 138%, and distal colon by 144%. Mitotic activity was greatest in the small intestine; the mitotic index was high (40%) compared with indexes in the stomach and hindgut (approximately 4%) even at emergence, and increased to approximately 60% by mid-summer. Microbial activity in the caecum was also significant at emergence. The stomach (length) and caecum (length and fresh mass) increased in response to ingested food earlier than did the small intestine. Between mid-summer and September there were decreases in small intestinal tissue mass and mitotic activity. It is concluded that the gastrointestinal tract of alpine marmots probably continues to function throughout hibernation at a low level, with a mid-winter trough as part of an endogenous circannual rhythm. However, after emergence in spring, increases in size and activity of the tract appear to be a response to ingested food rather than to an endogenous signal. The early signs of down-regulation of the small intestine before re-entry into hibernation, together with its delayed up-regulation in response to food in spring, are consistent with the high costs of maintaining this section of the digestive system.

Severe ovarian hyperstimulation syndrome (OHSS) and icterus.

Severe ovarian hyperstimulation syndrome (OHSS) leads to changes in laboratory analyte concentrations. Whereas elevated aminotransferase activity is often observed, a cholestatic course with hyperbilirubinaemia and icterus seldom occurs. In this report, the case of a 33 year old patient with polycystic ovary syndrome (PCOS) is described who, after stimulation with human menopausal gonadotrophin (HMG), developed severe OHSS with haemoconcentration, ascites, hydrothorax, elevated aminotransferases, hyperbilirubinaemia and icterus. The patient did not become pregnant and the OHSS regressed, together with the normalization of laboratory and clinical parameters and disappearance of the icterus. During the course of an OHSS cholestasis with icterus may occur, which could be explained by a reactive cholestatic hepatosis as a reaction to the hormonal changes induced by the stimulation therapy.

Evaluation of the Abbott IMx ultrasensitive II hTSH immunometric assay in three European centres: a comparison with established commercial immunometric assays for thyrotropin.

The Abbott Ultrasensitive II hTSH assay was evaluated in three European centres and its performance compared with its predecessor and with commercially available kits. A total of 408 individuals was included in the study (140 euthyroid, 116 hyperthyroid and 86 hypothyroid subjects, as well as 26 patients with non-thyroidal illness and 30 patients with thyroid cancer). The kit was evaluated for (im)precision and analytical and functional sensitivity according to ECCLS-Guidelines. The analytical sensitivity lay between 0.004 and 0.013 mU/1, the mean value being 0.008 mU/1, results being from 12 runs. The functional sensitivity gave a coefficient of variation below 20% at a concentration of 0.05 mU/1 under routine conditions. Inter-assay precision was less than 7% at 0.25 mU/l (range 5.3-6.8%), less than 6% at 6 mU/l (range 4.0-5.2%) and less than 9% at 30 mU/l (range 6.5 - 8.7%). Intra-assay (im)precision was not calculated as the Abbott IMx is designed to run on singlicate determinations.

The fetal vascularisation of term human placental villi. II. Intermediate and terminal villi.

Vessel arrangement and vessel structure of the intermediate and terminal villi of 50 human normal term placentas have been studied by means of semithin histology, three-dimensional reconstruction of serial sections as well as scanning electron microscopy of vessel casts. The reliability of the methods applied has been checked by a morphometrical comparison of the luminal diameters obtained. The mature intermediate villi are characterized by the presence of 1 to 2 terminal arterioles as well as 1 to 2 postcapillary venules, and a few moderately coiled, mostly narrow capillaries, some of which belong to the so-called paravascular network. The remaining capillaries are continuous with the capillary loops of the terminal villi. The fetal vessels of the terminal villi are represented by capillary loops only, parts of which are sinusoidally dilated, reaching diameters up to 50 micrometers. Depending on the method, the mean vessel diameter of the terminal villi is 12.3 (vessel casts) or 14.5 micrometers (semithin sections). The capillaries of the terminal villi are arranged in such a way that 3 to 5 terminal villi are supplied by the same, multiply coiled capillary loop. The average capillary length of the paravascular net is 1,000 to 2,000 micrometers, that of the terminal villus capillary loops 3,000 to 5,000 micrometers. The extent of sinusoidal dilation rises with increasing capillary length, indicating that the main functional importance of the sinusoids is the reduction of blood flow resistance.

The fetal vascularisation of term human placental villi. I. Peripheral stem villi.

The fetal vascularisation of the most peripheral three generations of stem villi has been studied by means of semithin serial sectioning and scanning electron microscopy of vessel casts in 50 human term placentas. The vessel types have been classified according to the structure of the vessel walls. Stem villi with a diameter of 200-400 microns are characterized by one smaller artery and one small vein, some arterioles and venules and capillaries of the paravascular net. Stem villi of about 150 microns diameter contain arterioles and muscular venules besides the paravascular capillary network. The last generation of stem villi measuring 80 to 100 microns in diameter exhibit a terminal arteriole and a collecting venule as well as up to ten paravascular capillaries. The luminal width of the arterial and venous stem vessels is considerably smaller than described for other vascular beds. This may partly be due to postpartal vascoconstriction. The capillaries of the paravascular net normally to not show sinusoidal dilation. They are arranged as long, hairpin-like, poorly branched loops connecting the arterial and venous stem vessels to each other.