Ripening of the human uterine cervix related to changes in collagen, glycosaminoglycans, and collagenolytic activity

Connective tissue in biopsy specimens taken from the lower part of the uterine cervix in 40 pregnant women at various gestational ages was compared to that in similar biopsy specimens from 15 nonpregnant women. The concentrations of collagen, sulfated glycosaminoglycans, and hyaluronic acid decreased during pregnancy. At the gestational age of 10 weeks, the collagen concentration was 70%, and at term 30%, of that in the nonpregnant cervix. After delivery, no further decrease was observed. The extractability of collagen increased during pregnancy, as well as during labor. Also, the water concentration increased. An increase in the collagenolytic activity was observed with advancing gestational age. The 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gin-D-Arg hydrolytic activity (collagenase) and the concentration of leukocyte elastase increased gradually by a factor of 10. The physiologic importance of the collagen was also demonstrated, since the cervical dilatation time during spontaneous labor was long in women with high concentrations of collagen and short in women with low concentrations of collagen.

Central control of vasopressin release and thirst

The effects of changes in the composition and/or the volume of the extracellular fluid on central receptors involved in the regulation of water balance are discussed. A review of results obtained in adults is given, followed by a discussion of possible roles for vasopressin during the neonatal period.

Effects of hemorrhage on vasopressin secretion and arterial blood pressure during experimental diabetes insipidus in goats

The effect of hypotensive hemorrhage on plasma vasopressin (AVP) concentration and carotid blood pressure before and after induction of experimental diabetes insipidus (DI) was studied in the conscious goat. Bleeding to the point of blood pressure fall (blood loss 15-25% of the estimated blood volume) caused an immediate, approximately hundred fold, increase in the plasma AVP concentration in the normal animal. Hemorrhage to the same extent during DI did not affect the plasma AVP levels. A rather transient hypotensive response to bleeding was seen before disruption of the pituitary stalk, but during DI the recovery of the hemorrhage-induced hypotension was less effective. However, the normalization of the blood pressure after bleeding was slightly more efficient during the permanent than during the temporary phase of DI. It is concluded that an intact hypothalamo-neurohypophysial connection is necessary for the massive release of AVP normally seen in response to hypotensive hemorrhage. It is also confirmed that the lack of this hormonal response to bleeding is accompanied by an increased susceptibility to the hypotensive effect of hemorrhage.

Effects of water deprivation and hyperhydration in pregnant and lactating goats

The response to 30 h water deprivation was studied in 7 goats during the last month of pregnancy and during lactation with anestrus as the control period. Plasma osmolality and plasma Na concentration increased by about 4% in pregnant and lactating goats and by about 2% in anestral goats. Plasma AVP concentration rose by about 7 pg/ml in pregnant and lactating goats, but only by about 3 pg/ml during anestrus. PRA was elevated in pregnant animals, but dehydration caused only a minor further rise. Total plasma protein concentration was low in pregnant goats and did not increase during water deprivation, but it did so in lactating animals. Neither the hematocrit nor the plasma K concentration changed in response to dehydration. GFR fell by about 24% in pregnant goats and by 22% in lactating animals, but remained unchanged during anestrus. ERPF fell by 20% in lactating animals, but no consistent effect of the dehydration was seen during pregnancy and anestrus. Urine flow decreased by about 75% during pregnancy, 55% during lactation and 65% during anestrus with the highest urine osmolality observed during anestrus. Milk production was only slightly reduced, but the milk osmolality increased in parallel with that of the blood plasma. When allowed to drink at the end of the water deprivation period, pregnant goats immediately drank 2.5 +/- 0.5 litres, lactating goats 3.3 +/- 0.9 litres and anestral goats 1.1 +/- 0.3 litres. When hyperhydrated, pregnant goats excreted the excessive water more readily and showed less response to exogenous AVP than lactating and anestral animals. In conclusion, pregnant and lactating goats are obviously more susceptible to a shortage of water supply than anestral animals but can easily excrete an excess of water.

A serial study of fluid balance during pregnancy, lactation and anestrus in goats

Water and salt balance was studied in the same goats during pregnancy, lactation and anestrus. All goats increased their water intake during the course of pregnancy, but individual differences were large. In general, twin pregnant (TP) goats drank more water than single pregnant (SP) animals (3.4 +/- 0.4; N = 11 as compared to 2.5 +/- 0.3 litres/day; N = 5) during the last weeks of pregnancy. During lactation the high water intake TP goats persisted and the SP animals increased their intake to the same level as the TP goats. The water intake was reduced to about 2 1/day in both categories of animals during anestrus. Urine volume largely followed the changes in water intake in the individual animal. A continuous decrease in urine osmolality during the course of pregnancy occurred, but during lactation urine osmolality increased towards anestrus levels. TP goats generally retained more sodium than SP animals during pregnancy and during anestrus, whereas the figures were similar during lactation. Plasma Na, K and osmolality remained unchanged during pregnancy, lactation and anestrus, but a large fall in total plasma proteins and a moderate fall in hematocrit were observed during the course of pregnancy. Glomerular filtration rate of TP goats was elevated by about 35% during the 4th month of pregnancy, but did not differ from anestrus levels during the 3rd and 5th month or during lactation. Effective renal plasma flow was highest during the 3rd pregnancy month and then fell to reach lactation and anestrus levels during the 4th month of pregnancy. A few hours before parturition the animals became markedly dehydrated as shown by sudden increases in plasma Na, K, osmolality, total proteins and hematocrit. This water deficit was replenished within 26 h post-partum.

Effect of stress on myocardial cells and blood levels of catecholamines in normal and amygdalectomized pigs

The effects of restraint stress on heart activity, blood catecholamines and the development of myocardial necrosis were studied in five unoperated and five unsuccessfully amygdalectomized (sham-operated) pigs and compared with six bilaterally amygdalectomized pigs. In the sham-operated and the nonoperated animals, restraint stress often provoked intense tachycardia, as well as considerable elevations of blood catecholamines, particularly noradrenaline, associated with more or less widespread foci of myocardial necrosis. In contrast, the same restraint produced only minor heart rate increase in the six completely amygdalectomized animals; their blood noradrenaline levels were significantly lower and no myocardial necrosis could be detected, either macro- or microscopically. The results indicate that the amygdaloid part of the limbic system and the sympathoadrenal system are of importance in the induction of myocardial necrosis often noted in pigs when exposed to situations of severe mental stress.

Ring chromosome 14 in a mentally retarded girl

A case of ring chromosome 14 in a 12-year-old girl, showing mental retardation, epilepsy and minor somatic abnormalities, is described and compared with five previously reported cases with the same chromosome aberration.

Transient vasopressin release and thirst in response to prolonged intracerebroventricular infusions of hypertonic mannitol in saline

In the conscious goat infusions of 0.4 M mannitol in 0.15 M NaCl into the lateral cerebral ventricle (40 or 100 min, 0.02 ml/min) caused slight, transient vasopressin release and temporary thirst, whereas infusions or pure, hypertonic (0.7 M) mannitol did not elicit thirst and inhibited the basic vasopressin release in the nonhydrated animal. In contrast, infusions of equiosmolal (0.35 M) NaCl induced persistent thirst and pronounced elevation of the plasma vasopressin concentration throughout the infusion period. The cerebrospinal fluid (CSF) osmolality was raised by the same order of magnitude (= 13%) after the mannitol/NaCl and the hypertonic NaCl infusions. The CSF Na+ concentration was elevated by greater than 10% at 5 min after hypertonic NaCl infusions, but it was reduced by approximately 10% at 5 min after the mannitol/NaCl infusions. There was no appreciable difference in the CSF K+ concentration after the infusions. The results are discussed with regard to the possible importance of CSF Na+-concentration as opposed to strict osmotic factors for the excitation of receptors involved in the control of water balance.