Blastocyst-Derived Stem Cell Populations under Stress: Impact of Nutrition and Metabolism on Stem Cell Potency Loss and Miscarriage.

Data from in vitro and in vivo models suggest that malnutrition and stress trigger adaptive responses, leading to small for gestational age (SGA) blastocysts with fewer cell numbers. These stress responses are initially adaptive, but become maladaptive with increasing stress exposures. The common stress responses of the blastocyst-derived stem cells, pluripotent embryonic and multipotent placental trophoblast stem cells (ESCs and TSCs), are decreased growth and potency, and increased, imbalanced and irreversible differentiation. SGA embryos may fail to produce sufficient antiluteolytic placental hormone to maintain corpus luteum progesterone secretion that provides nutrition at the implantation site. Myriad stress inputs for the stem cells in the embryo can occur in vitro during in vitro fertilization/assisted reproductive technology (IVF/ART) or in vivo. Paradoxically, stresses that diminish stem cell growth lead to a higher level of differentiation simultaneously which further decreases ESC or TSC numbers in an attempt to functionally compensate for fewer cells. In addition, prolonged or strong stress can cause irreversible differentiation. Resultant stem cell depletion is proposed as a cause of miscarriage via a "quiet" death of an ostensibly adaptive response of stem cells instead of a reactive, violent loss of stem cells or their differentiated progenies.

A comparison of behaviour following stimulation of the anterior substantia nigra by direct cholinergic agonists and anticholinesterases.

Microinjections of carbachol, a muscarinic cholinergic receptor agonist, into the anterior substantia nigra increase feeding, drinking and sexual behaviour if there is a pre-existing tendency to respond and a low baseline rate of behaviour. The present experiment was undertaken to compare the effects of carbachol with other cholinergic stimulants. Groups of 6-12 satiated rats received 0.5 microliter microinjections into the anterior substantia nigra of 0.1-5.0 micrograms carbachol, 0.1-5.0 micrograms nicotine, 2.5-10.0 micrograms eserine, and 1.25-5.0 micrograms or 0.1-1.0 microgram neostigmine (each dissolved in sterile saline) and the effects on feeding, drinking, locomotion, grooming, rearing and sniffing were examined. Carbachol, nicotine and low doses of neostigmine stimulated eating in a dose-dependent manner. The increased feeding following neostigmine was over a shorter time-period than following carbachol or nicotine. Neither carbachol nor nicotine had any significant effect on behaviour other than eating. The higher doses of neostigmine increased the frequency of sniffing and rearing, but not eating, and no dose of eserine had a clear effect on behaviour. These data are discussed in terms of their relationship to the cholinergic input to substantia nigra which excites pars compacta dopamine-containing neurones.

Additivity of nicotinic and muscarinic cholinergic stimulation of substantia nigra.

Microinjection of cholinergic agonists into the anterior substantia nigra increases behaviours for which there is a pre-existing tendency and a low current rate. Rats received microinjections of carbachol, nicotine or a combination of both into the anterior substantia nigra. Carbachol and nicotine both stimulated consumption of palatable food in a dose-dependent manner (F(3,24) = 3.99, p < 0.02 and F(3,33) = 7.07, p < 0.01 respectively). Addition of carbachol to each dose of nicotine caused a significant increase in feeding compared with nicotine alone (F(1,23) = 7.01, p < 0.015). This suggests muscarinic or nicotinic cholinergic stimulation of the anterior substantia nigra can have behaviourally similar effects and, at the doses used here, the effects of nicotinic and muscarinic stimulation are additive.

5-HT receptor blockade in the posterior amygdala elicits feeding in female rats.

Previous work suggests that feeding following intraventricular (i.v.t.) injections of the serotonin (5-HT)(1/2/7) antagonist metergoline (MET) is not localized to the hypothalamus. Since lesions of the posterior basolateral amygdala (pBLA) block feeding following systemic 5-HT1A agonist 8-hydroxy-2(di-n-propylamino)tetralin, the ability of intra-pBLA MET to elicit feeding was investigated. In two separate experiments, feeding of female rats was measured over 2 h following 0, 3, 10 and 30 nmol and 0, 0.03, 0.3 and 3 nmol MET (mol. wt. 403.5) injected bilaterally into each pBLA. All three doses used in Experiment 1 increased feeding over 2 h. In Experiment 2, feeding over the first hour was enhanced after the two highest doses. Since intra-pBLA MET elicits feeding comparable to that seen using much higher doses administered i.v.t. these data implicate the pBLA as an extra-hypothalamic site mediating the effects of 5-HT in feeding control.

Posterodorsal amygdala lesions reduce feeding stimulated by 8-OH-DPAT.

Injections of the serotonin (5-HT)(1A) agonist, 8-hydroxy-2(di-n-propylamino)tetralin, (8-OH-DPAT), either systemically or into the midbrain raphe nuclei, elicit food intake in otherwise satiated rats. Lesions of the paraventricular nucleus of the hypothalamus are well known for producing long-term overeating, but past research has excluded this site as a potential locus for short-term 8-OH-DPAT feeding effects. More recent work shows that small lesions of the posterodorsal amygdala (PDA) elicit overeating in their own right. Since this and related regions of the amygdala receive 5-HT innervations from the dorsal raphe nucleus (DRN), we determined if PDA lesions might alter feeding after injecting 8-OH-DPAT into this midbrain region. Adult female rats received either bilateral electrolytic lesions of the PDA or sham lesions. After recording weight gains for over 1 month, all rats were implanted with DRN cannulae, then randomly tested every 3-4 days for 1 h intake of standard lab chow after 0, 0.4, 0.8 or 1.6 nmol injections of 8-OH-DPAT. Additional 90 min measures of intake were also made after 0 vs. 250 microg (760 nmol) 8-OH-DPAT s.c. At the two highest DRN doses tested, lesioned rats showed 50% less intake compared to shams. A similar profile emerged after the single s.c. dose. These results suggest that the PDA may be an important locus at which reduced release of endogenous 5-HT stimulates feeding. Alternatively, the PDA may represent part of a larger brain circuit whose integrity is necessary for eliciting intake in response to a variety of feeding stimuli.

Whole-body metabolism varies across the estrous cycle in Sprague-Dawley rats.

Food intake in rats and other mammals is lowest at estrus and highest at diestrus. While much is known about the effects of different estrous phases on energy intake, as well as some of the metabolic effects the associated hormones exert, little has been reported about changes in whole-body metabolism that accompany those phases. This study investigates how energy expenditure (EE) and respiratory quotient (RQ) vary in intact female Sprague-Dawley rats (n=12) tested mid-light cycle over 2 h on days associated with estrus vs. diestrus. Rats showed small but reliable decreases in body weight on days associated with estrus, but not diestrus. EE was significantly increased by approximately 21% on the day associated with estrus compared to diestrus. At the same time, RQ was significantly decreased by approximately 7% on the day associated with estrus, indicating a relative shift to fat over carbohydrate as the energy substrate to support energetic needs. Future investigations of ingestive processes can integrate the present findings to investigate how gender differences in feeding and metabolism contribute to regulatory behaviors.

NMDA lesions of lateral hypothalamus enhance the acquisition of schedule-induced polydipsia.

Schedule-induced polydipsia (SIP) is affected by damage to various limbic structures that have connections with the lateral hypothalamus. The present experiment sought to determine whether or not SIP could be induced in rats bearing NMDA-induced lesions of the lateral hypothalamus. Following surgery, lesioned rats lost weight and were hypophagic and hypodipsic. Drinking, in response to systemic injection of hypertonic saline, was impaired in lesioned rats. Prior to testing for SIP, all rats were placed on a food-restriction regime to maintain body weight at 85% of normal. There was no statistically significant difference in mean body weight between lesioned and control groups before deprivation began, though lesioned rats were hypodipsic in their home cages. The lateral hypothalamic-lesioned rats acquired SIP significantly more rapidly than controls over the first six sessions, but over four following sessions no differences were present. The enhanced acquisition of SIP by lateral hypothalamic-lesioned rats cannot be accounted for by postoperative recovery of body weight or by hypodipsia in the home cage, neither of which correlated with SIP. It is suggested that the lateral hypothalamus has a role in cueing appropriate and inhibiting inappropriate behavior in conditions of motivational excitement. SIP is suggested to have two CNS components--one excitatory and one inhibitory.

Lesions of the posterior basolateral amygdala block feeding induced by systemic 8-OH-DPAT.

We have recently reported that bilateral electrolytic lesions of the posterodorsal amygdala (PDA) in female rats which induce protracted overeating and weight gain also attenuate short-term feeding stimulated by intraraphe infusions of the serotonin (5-HT) 1A agonist, (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin, (8-OH-DPAT). Bilateral lesions of the posterior basolateral amygdala (pBLA) in male rats have also been reported to enhance feeding and weight gain, but much less so than PDA lesions do in female rats. The present study was performed to determine if pBLA lesions in female rats might attenuate 8-OH-DPAT feeding and what, if any, relationship exists between 8-OH-DPAT-induced feeding and lesion-induced weight gain. Lesioned rats showed reliable increases in 24-h food intake and weight gain relative to shams during the days between surgery and acute drug-induced feeding tests. 8-OH-DPAT (0, 60, 120 or 240 microg/kg in saline) increased feeding of shams in a dose-dependent manner over 2 h. Feeding at the most effective dose (120 microg/kg) was reduced to vehicle levels in lesioned rats. The feeding induced by this dose correlated inversely (r=-.59, P<.01) with the magnitude of weight gained following lesions. Feeding at the highest dose (240 microg/kg) showed a biphasic effect of feeding inhibition over the first vs. second hour that was unaffected by lesions. These findings imply that either fibers of passage and/or cellular elements in both the PDA and pBLA normally inhibit overeating and weight gain via intact serotonergic mechanisms.

The use of a "reverse" axis (axillary-interscalene) block in a patient presenting with fractures of the left shoulder and elbow.

IMPLICATIONS: A patient presented for surgery to repair a fractured left shoulder and elbow and requested regional anesthesia. Most upper extremity operations require a single brachial plexus nerve block. The position of the two fractures however required the use of two separate approaches, an interscalene and an axillary approach.

Tube introducer and modified Celestin tube for use in palliative intubation of oesophagogastric neoplasms at fibreoptic endoscopy.

A new method for palliative intubation of inoperable neoplasms at or near the cardia is described. A guidewire is passed through the stricture, which is dilated using Eder Puestow metal olive dilators. The tube to be inserted is mounted on an introducer, which grips its distal end from inside, and is slid into position along the wire under radiological control. Twenty-five patients have been intubated with one death directly resulting from the procedure. The method provides a simple and relatively safe means of relieving dysphagia and improving nutrition.

Cholinergic stimulation of substantia nigra: abolition of carbachol-induced eating by unilateral 6-hydroxydopamine lesion of nigrostriatal dopamine neurones.

Microinjection of cholinergic agonists into the substantia nigra is known to elicit increases in eating, drinking and sexual behaviour under appropriate circumstances. It has been suggested that these effects are dependent on stimulation of nigrostriatal dopamine-containing neurones in the substantia nigra pars compacta, but no direct evidence has confirmed this. The present experiment was therefore undertaken to determine whether unilateral lesions of nigrostriatal dopamine neurones made by 6-hydroxydopamine would attenuate or abolish eating in satiated rats elicited by intranigral microinjection of the muscarinic agonist carbachol. Two groups of rats were tested: a 6-hydroxydopamine- and a sham-lesion group. Before lesions were made intranigral microinjection of 0.5 microgram/0.5 microliter carbachol stimulated significantly more eating than control microinjections in both groups. After 6-hydroxydopamine lesions, microinjection of carbachol elicited no more eating than vehicle alone. Rats given sham lesions (ascorbate-saline vehicle only) showed increased feeding to intra-nigral carbachol before and after sham-lesioning. Post-mortem analysis by HPLC was used to determine the concentration of dopamine, DOPAC, HVA, serotonin and 5-HIAA in the lesioned and non-lesioned hemispheres of both 6-hydroxydopamine- and sham-lesioned rats. In caudate-putamen there were significant reductions in the concentration of DA (to 50.03% of the level in control sides), DOPAC (to 49.34%) and HVA (to 63.98%) in the 6-hydroxydopamine-lesioned but not sham-lesioned rats. The concentration of dopamine, DOPAC and HVA were not affected in the nucleus accumbens. The turnover of dopamine (assessed by calculating the ratio of dopamine to DOPAC) in the caudate-putamen but not nucleus accumbens was also altered by the 6-hydroxydopamine lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Horner syndrome due to thoracic epidural analgesia in a paediatric patient.

A 4-year-old boy with coarctation of the aorta underwent surgical aortic arch repair with general anaesthesia and thoracic epidural analgesia. In the immediate postoperative period, the child developed a unilateral Horner syndrome which appeared to be related to the epidural infusion rate. Management of this patient as well as alternate aetiologies of Horner syndrome are described. Horner syndrome is a rare complication of epidural catheters and is often unrecognized, especially in children.