Cardiovascular effects and modulation of noradrenergic neurotransmission following central and peripheral administration of neuropeptide Y

Experiments have been conducted to evaluate the effect of neuropeptide Y (NPY) administered at three distinct levels of the nervous system: 1) the posterior hypothalamic nucleus, 2) the spinal cord, and 3) the vascular noradrenergic neuroeffector junction. It was observed that NPY produced varying cardiovascular effects at these three distinct sites of the nervous system. Microinjections into the posterior hypothalamic nucleus resulted in an increase in blood pressure, which was reduced by prior microinjection of a muscarinic or H1-histamine antagonist but not an H2-histamine antagonist. In addition to the involvement of histaminergic and cholinergic pathways, the pressor effect of NPY appears to result from an increase in sympathetic outflow. NPY was also seen to decrease the potassium-induced release of norepinephrine (NE) from slices obtained from the posterior hypothalamic nucleus. In contrast to what was observed in the hypothalamus, the intrathecal injection of NPY at a level of T4 or T10 in anesthetized or T10 in unanesthetized rats resulted in a depressor effect as well as a decrease in heart rate. Both an alpha 2- and beta-adrenoceptor antagonist reduced the NPY effect. The depressor effect of intrathecal NPY was attenuated in rats pretreated with reserpine as well as in Spontaneously Hypertensive rats (SHR). These data suggest that the effects of NPY are closely associated with sympathetic preganglionic neurons in the spinal cord. At the vascular noradrenergic neuroeffector junction, NPY decreased the nerve stimulation-induced release of NE while potentiating the contractile response. Moreover, NPY potentiated the increase in perfusion pressure of the perfused mesenteric arterial bed in response to angiotensin, vasopressin, or phenylephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Caudate hemorrhage

We studied 12 patients with intracerebral hemorrhage in the head of the caudate nucleus. These cases accounted for 7% of a consecutive series of intracerebral hemorrhage. The clinical findings differed from more common varieties of supratentorial hemorrhage. All patients had acute onset of vomiting, headache, stiff neck, decreased level of consciousness, and behavioral changes in a pattern that simulated subarachnoid hemorrhage. Seven patients had gaze paresis and hemiparesis, with or without sensory loss. Two of these seven patients had, in addition, elements of Horner's syndrome. The prognosis for recovery was good. No patient had recurrent hemorrhage or persistent hydrocephalus.

Duplication 9q34 syndrome

Phenotypic, karyotypic, and developmental homology between affected children of carriers of an inverted insertion (9) (q22.1q34.3q34.1) led to recognition of a new chromosome syndrome: dup 9q34. Individuals with dup 9q34 have slight psychomotor retardation, understand simple directions, and acquire a limited vocabulary. In childhood, many are hyperactive. Clinical features include low birth weight, normal birth length, and initial poor feeding and thriving. Musculo-skeletal systems are affected: there are joint contractures, long thin limbs, and striking arachnodactyly. There is abnormal implantation of the thumb, increased space between the first and second fingers, and excess digital creases. Marfan syndrome was a provisional diagnosis for several cases prior to cytogenetic analysis. Cardiovascular and ocular systems are minimally affected, erythema and heart murmurs occur, and ptosis and strabismus are frequent, but lens dislocation is not observed. Features at birth include: dolichocephaly, facial asymmetry, narrow horizontal palpebral fissures, microphthalmia, prominent nasal bridge, small mouth, thin upper lip with down-turned corners, and slight retrognathia. In older children, retrognathia is diminished and the nose becomes long and narrow. The new culture and chromosome banding techniques enable sorting of cases with the distal dup 9q phenotype into two groups. The cases with a longer dup 9q are more likely to develop with life-threatening congenital anomalies. The cases with the shorter dup 9q34 have a less severe long-term prognosis and will benefit, together with their parents, from special education. Female carriers of the inv ins(9) (q22.1q34.3q34.1) have about a 31% risk in each pregnancy to conceive a fetus affected by the dup 9q34 syndrome. A comparable figure is not yet available for male carriers.

Cytomegalovirus infection in pregnancy: preliminary findings from a prospective study

8278 (56%) of 14 789 pregnant women who were screened for cytomegalovirus (CMV) antibodies at their first antenatal visit were seropositive. 42 (3 per 1000) infants screened were congenitally infected. 3 (7%) have serious handicaps, 14 (33%) have minor or transient problems, and 25 (60%) have so far had no problems. In 26 of the 42 mothers with infected infants CMV antibodies were present in the first antenatal blood sample. 28 (67%) of the infected infants were born to mothers who had experienced a primary infection in pregnancy and 7 (17%) to mothers who had experienced recurrent infection. In the remaining 7 (17%) it was not possible to determine the type of maternal infection. One handicapped infant was born after a probable recurrent CMV infection during pregnancy. These preliminary findings suggest that routine screening of pregnant women to detect evidence of primary CMV infection is not helpful.

An evaluation of dynamic pituitary function tests in patients with pituitary tumours

In a prospective study of 26 patients with macroadenoma of the pituitary (14 secretory and 12 non-secretory), basal and stimulated pituitary hormone levels were used to detect hypothalamic dysfunction and to examine pituitary hormone secretion before and after hypophysectomy. Suprasellar tumour extention with hypothalamic compression occurred in 18 patients but was not consistently associated with hormonal tests indicative of hypothalamic dysfunction. In patients with secretory tumours, secretory activity was adequately assessed by basal hormone levels alone, which showed that surgery reduced hormone levels by a mean 85% in acromegaly and by a mean 55% in prolactinomas. Preoperatively, pituitary reserve of hormones not being hypersecreted was often normal, despite large tumour size and hypothalamic compression. Even after apparently complete pituitary removal at surgery, normal responses to stimulatory tests could sometimes be detected. Conventional dynamic tests are only of limited value in the assessment of hypothalamo-pituitary dysfunction in patients with large pituitary tumours and should not be used indiscriminately in such individuals requiring surgery.

Effect of supplemental glucose or sucrose on liver and carcass glycogen metabolism of young chicks

An experiment was conducted with Leghorn chicks to evaluate the effect of glucose or sucrose on liver and carcass glycogen. Phosphorylase a and synthase a were assayed to learn if glycogen cycle enzymes could be influenced by the early plane of nutrition. Both glucose and sucrose in drinking water increased liver and carcass glycogen in 3-day-old chicks. Groups given sucrose had more liver glycogen than groups given glucose after 5 days. Supplementary glucose given to fed chicks resulted in an increase in glycogen synthase a and a decrease in glycogen phosphorylase a at 4 days of age. By 6 days of age, differences in synthase activity between groups given sucrose or glucose were small. However, glucose solutions decreased phosphorylase a activity. The relationship between synthase a and phosphorylase a also partially regulates glycogen metabolism.

Control of glycogen metabolism in the developing turkey poult

An experiment was conducted with young turkey poults to evaluate factors controlling glycogen metabolism in the period following hatching. Glucose and sucrose solutions were given along with a standard starter diet. Liver and carcass glycogen were measured on days 1, 4 and 6. Liver glycogen synthetase (EC 2.4.1.21) and phosphorylase (EC 2.4.1.1) were also assayed at these times. The characteristics of active and inactive glycogen synthetase at these times were determined and sensitivity of the active and inactive forms were related to physiological concentrations of glucose-6-phosphate. Supplemental glucose or sucrose increased carcass glycogen in comparison to controls; however, but sucrose was more effective than glucose in promoting liver glycogen synthesis in 4- and 6-day-old poults. There was an age dependent increase in carcass glycogen between days 1 and 6, but a decrease in liver glycogen between days 4 and 6. The activation of liver glycogen synthetase is incomplete in 1 day old poults but activity increases during the 1st week of life. Activation of glycogen synthetase decreased the apparent Ka for glucose-6-phosphate. Phosphorylase inactivation in vitro was not affected by age. Liver glucose-6-phosphate increases rapidly after hatching and the concentration is related to the in vitro Ka derived for both active and inactive synthetases. Both glucose and sucrose increased liver glucose-6-phosphate at days 4 and 6 as well as glycogen synthetase activity. The increase in enzyme activity may be caused indirectly by an allosteric effect of glucose-6-phosphate. Phosphorylase, while not affected by supplemental carbohydrates, did decrease in activity between days 4 and 6. The decrease in activity could affect the phosphorylase a/ synthetase a ratio and change glycogen metabolism.

Effect of dietary energy on hepatic glycogen metabolism in the turkey hen

An experiment was conducted with turkey hens to investigate the effect of substituting 30% of the carbohydrate calories with corn oil, 1,3-butanediol, or glycerol. Birds fed additional corn oil had the lowest liver glycogen concentration. Corn oil increased phosphorylase, a total phosphorylase, and glycogen synthetase I in comparison to the controls. Also, additional corn oil resulted in the highest specific activity of glucose-6-phosphatase. Dietary glycerol caused the highest concentration of liver glycogen. Glycerol increased glycogen synthetase I, but had little effect upon total activity in comparison to butanediol in the diet. Both butanediol and glycerol gave similar phosphorylase a activity, but butanediol increased total activity. The fat-fed and control-fed hens regulated hepatic glycogen concentration through phosphorylase, while glycerol and butanediol-fed hens regulated glycogen through glycogen synthetase. In vitro activation of glycogen synthetase I was deficient in hens fed additional corn oil, indicating a lack of glycogen synthetase phosphatase activity. The order of activation (glycerol greater than butanediol greater than control greater than corn oil) corresponds to the rank of glycogen concentrations

Glycogen depletion and repletion in the chick

Carcass glycogen was degraded by chicks at a faster rate than liver glycogen during the first 72 hr of a 120 hr fast. Degradation of both sources of glycogen proceeded at a slower rate during the final 48 hr. Carcass glycogen was repleted at a greater rate than liver glycogen.

Glycogen metabolism in the turkey embryo and poult

Fertile eggs from Large White turkey hens were classified according to weight at time of incubation. Glycogen was measured in the 21-day-old embryo and one-day-old poult. Liver glycogen was positively correlated with initial egg weight in the 21-day-old embryo and negatively related to initial egg weight in the one-day-old poult. Glycogen recycling was evident in the one-day-old poult. Maximum accumulation of 14C-glucose as glycogen occurred 60 min post injection. Liver phosphorylase a level was higher in the one-day-old poult than the embryo. Total phosphorylase per gram of liver tissue was not different between the two age groups. Liver phosphorylase b was subject to conversion to phosphorylase a in both age groups. Avian phosphorylase exists in both the active and inactive form.

Muscle protein catabolism in the septic patient as measured by 3-methylhistidine excretion

Muscle protein catabolism has been evaluated using the excretion of urinary 3-methylhistidine (3-MEH) is six normal male and six normal female subjects and in four surgical patients, two of whom developed febrile episodes during the course of their study. In addition, their nutritional status was also evaluated using percentage body weight losses before hospital admittance, creatinine-height ratios, and, in two patients, serum alkaline ribonuclease levels. The results indicate that: 1) prolonged starvation may produced decreased 3-MEH excretion because of an adaptive diminution of muscle breakdown in sustained starvation, decreased 3-MEH excretion also may simply reflect diminished lean body mass, 3-MEH excretion may be increased above basal levels because of superimposed stresses such as fever, and the acute phases of starvation produce increased levels of 3-MEH excretion until adaptive mechanisms occur; 2) creatinine-height ratios are low in starvation, and increase not only with improved nutrition but in response to fever and stress of operation, even when these are superimposed on malnutrition; and 3) alkaline RNAase levels are elevated in malnutrition and decrease with improved nutrition but in response to fever and stress of operation, even when these are superimposed on malnutrition; and 3) alkaline RNAase levels are elevated in malnutrition and decrease with improved nutrition. The enzyme may also be elevated by the stress of operations.

Cellular glucose utilization during hemorrhagic shock in the pig

To clarify the changes in glucose homeostasis which occur following injury, pigs were subjected to hemorrhagic shock. During shock increased levels of free glucose occurred in red blood cells and muscle tissue, suggesting that inhibition of glucose phosphorylation was occurring. Simultaneously systemic plasma glucose levels were noted to be higher than portal plasma glucose levels while levels of free glucose within the liver fell, indicating that the liver was mobilizing glucose. Plasma insulin and phosphate levels were observed to rise throughout the experiment. From this study it was concluded that the hyperglycemia of injury in these animals was caused by a combination of decreased cellular glucose utilization due to diminished phosphorylation and increased mobilization of glucose by the liver.

Glucose utilization and insulin secretion during surgery in man

Intravenous glucose tolerance tests were performed in 18 patients before, during and after surgery. Glucose utilization was found to be significantly depressed during and after operation to a degree which increased with the severity of operation. Suppression of insulin secretion was observed during operation together with increased plasma cortisol levels and an increased urinary catecholamine excretion. It is suggested that a failure of cellular glucose utilization is the primary event in the metabolic response to injury which initiates cellular catabolism and urinary nitrogen loss.