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Biomedical subjects

R G Thompson

Publications and source records attributed to R G Thompson.

At least 73 records · Page 4Linked to original sources
PubMed1978

Endogenous norepinephrine and serotonin within the hippocampal formation during the development and recovery from septal hyperreactivity.

Fluorometric analysis of serotonin (5-HT) and norepinephrine (NE) content of the hippocampal formation revealed that biogenic amines are distributed heterogeneously in the dorsoventral axis, and that NE also exhibits a heterogeneous distribution in the medial-lateral direction while 5-HT does not. Dissection of the hippocampus into its dorsal and ventral halves shows that both NE and 5-HT exhibit higher concentrations in the ventral hippocampus in comparison to its dorsal counterpart. A dissection which separated the cell fields CA 1 and 2 from CA 3 and 4 and the dentate gyrus showed NE to be the highest in the latter region, while 5-HT was uniformly distributed between the two regions. Taken together, these data indicate that NE is more highly concentrated in the CA 3 and 4 and dentate area of the ventral hippocampus while 5-HT concentration differences are apparent only in a dorsal-ventral dissection. Concentrations of NE and 5-HT in the dorsal and ventral hippocampus were also determined at 1, 3, 6, 11, 16, 24, and 30 days following a lesion to the septal nuclei. The results demonstrate that biogenic amine levels in the dorsal hippocampus achieve maximal depletion earlier than do their ventral counterparts, and that percent depletion is greater for 5-HT than NE in both dorsal and ventral areas. On the first day following septal lesions, 5-HT is increased above normal levels. Sixteen days after septal lesion, 5-HT is substantially depleted below normal levels. In addition, by 30 days, 5-HT shows significant return toward normal levels from its earlier depleted state. Behavioral changes related to sensory reactivity correlate with the relative decreases of NE and 5-HT following septal lesions.

Animals↗
PubMed1978

Chemical diabetes in childhood. Integrated concentrations of glucose, insulin, and growth hormone.

Children and adolescents with varying degrees of glucose intolerance were studied with constant, blood withdrawal methods, and concentrations of glucose, insulin, and growth hormone were evaluated during a normal twenty-four-hour routine. Integrated concentrations of glucose and insulin in children with chemical diabetes were normal despite abnormal oral glucose-tolerance tests. All but two insulin-dependent diabetics had elevated integrated concentrations of growth hormone, as did some but not all chemical diabetics. Three of four mildly ketoacidotic individuals with newly diagnosed diabetes, who were studied before insulin therapy, had normal growth hormone-integrated concentrations. These data differentiate pharmacologic and physiologic assessments of carbohydrate homeostasis, and they support the concept that elevated growth hormone concentrations may not be a direct result of poor diabetic control.

Adolescent↗
PubMed1977

The current status of protein sparing.

Solutions of crystalline amino acids infused without dextrose produce a marked improvement in nitrogen balance. Increasing the infusion level of amino acid from 1.0 to 1.7 grams per kilogram further improves nitrogen balance. The addition of dextrose to the amino acid solutions did not affect nitrogen balance and proved that the role of insulin during protein sparing has been overemphasized. Nitrogen balance is slightly, but not significantly, superior when nonprotein dextrose calories are administered. However, amino acid solutions are isotonic and can be infused peripherally, whereas adding dextrose doubles the concentration and renders peripheral infusion more difficult. Protein sparing may be useful for short term nutritional support when the potential risks of total parenteral hyperalimentation are not justified. Endogenous body fat is mobilized. Hence, protein sparing also prevents the development of fatty acid deficiency and may be useful in treating fatty infiltration of the liver. Protein sparing provides suboptimal caloric replacement and should only be used for temporary nutritional support until oral alimentation is resumed or until there is an absolute indication for intravenous hyperalimentation. Expense and the fact that most patients do well after elective abdominal operations militate against the proposition that amino acids should become a routine substitute for 5 per cent dextrose therapy post-operatively.

Amino Acids↗
PubMed1976

Metabolic and hormonal responses to a protein-glucose meal in normal infants and in marasmus and marasmic kwashiorkor.

Blood sugar and plasma free fatty acids (FFA), immunoreactive insulin (IRI), and growth hormone (GH) responses to a protein-glucose meal were determined in normal infants and those with marasmus and marasmic kwashiorkor. Among the normal subjects, fasting blood sugar (BS), peak BS and IRI, and the IRI/BS ratio tended to decrease as age increased. Peak IRI was at least 13muU/ml above fasting in 21 of 24 infants. Fasting GH levels were high 38.5 +/- 13.6 (SD) and 26.3 +/- 14.0 ng/ml, in the two youngest groups (under 1 year) and were comparable with those of the late newborn period. They were slightly lower, 20.8 +/- 22.1, in those 12.5-18.5 months of age. Suppressions of FFA and subsequent rebounds were in close temporal relation to BS and IRI peaks and lows, but not the GH levels. GH was promptly suppressed by the meal, and in most infants secondary elevations were seen. Untreated marasmic infants had normal or low BS, correspondingly normal or low IRI, markedly elevated FFA (1,821 +/- 588 muEq/liter), and GH levels comparable with those of the control subjects. There was some delay in BS elevation and disappearance and poor insulin release after the meal, with only two of nine having elevations of at least 13 muU /ml The BS elevations and IRI responses, however, were adequate to block FFA release. GH levels were poorly suppressed by the meal but some infants had further elevations, possibly in response to protein. After partial rehabilitation, fasting BS and FFA and BS elevations after the meal were normal. A slight improvement in insulin release was apparent. Fasting GH levels and responses to the meal were normal. Fasting, minimally treated children with marasmic kwashiorkor (MK) had normal or low BS, normal or low IRI, normal FFA, and probably normal GH levels. There was considerable delay in BS elevation, moderately delayed glucose disappearance, and very poor or unmeasurable insulin release after the test meal; FFA and GH were poorly suppressed. After partial rehabilitation, fasting BS was normal, FFA levels were (630 +/- 163 muEq/l), IRI was still low, BS elevations and disappearance improved. IRI responses modestly improved, and GH responses were normal.

Age Factors↗
PubMed1976

Integrated concentrations of luteinizing hormone and puberty.

Integrated serum concentrations of luteinizing hormone have been compared among 30-minute collections from 10 boys (6-18 years old) and 5 girls (5-11 years old). This study suggests that perpubertal as well as pubertal boys have greater mean integrated concentrations of LH during sleep than during waking. One of two pubertal girls had greater concentrations of LH during sleep, while three prepubertal girls did not.

Adolescent↗
PubMed1976

Juvenile-onset diabetes.

While information regarding the diagnosis of diabetes and acute care of the diabetic, i.e., management of ketoacidosis, is readily available, much less has been written about long-term management. In addition to a brief review of background information and recent developments in diabetes, some of the more common management problems are discussed from a practical viewpoint. Because an exhaustive review of diabetes is beyond the scope of this article, readers are referred to recent review articles for additional background information.

Adult↗
PubMed1975

Interaction between local anesthetics and analeptic drugs.

Although clinicall undesirable, the fortuitous pharmacologic interactions between local anesthetic agents and analeptic drugs may be protective when large doses of both agents are used. Mice pretreated with procaine, lidocaine, and tetracaine had a lower incidence of seizures when convulsive doses of either nikethamide or doxapram hydrochloride were given intraperitoneally. Mortality was also decreased in the groups given nikethamide and was zero in the animals treated with doxapram. All animals treated with pentylenetetrazol convulsed and only lidocaine (also used as an anticonvulsant) was able to reduce mortality in this group. Of the local anesthetic agents, tetracaine afforded the least protection from death, whereas lidocaine seemed to be most effective.

Anesthetics, Local↗
PubMed1975

Circadian variation of integrated concentration of growth hormone in children and adults.

A portable constant withdrawal pump was used to determine consecutive 30-min integrated concentrations of growth hormone (ICGH) for a 24-h period in 18 normal subjects, ages 5 to 28 yr. Seven prepubertal, 5 pubertal and 6 young adult subjects were studied under conditions of normal activity. Pubertal, prepubertal, and adult subjects had peaks during waking hours as well as during sleep, but peaks in the adults were usually lower than in the children. Using an analysis of variance, a significant (P smaller than 0.01) downward trend of ICGH was observed to occur during sleep. During waking hours a significant variation (P smaller than 0.01 by analysis of variance) was found with low levels in the first few hours after awakening and an upward trend as the evening approached. Food intake had no significant effect on ICGH nor did the introduction of the indwelling catheter. The mean apparent half-life values of growth hormone calculated on the basis of 87 episodes with 3 or more points on the downslope was 40.1 min. This is significantly higher than the known true half-life of the hormone, suggesting that complete secretory inactivity after a secretory episode is an infrequent event.

Adolescent↗
PubMed1975

Trimming as a means of removing patulin from fungus-rotted apples.

Penicillium expansum 1071, 1172, NRLL 973, and Penicillium patulum ATCC 24550 were inoculated into Red Delicious, Golden Delicious, and McIntosh apples. The decayed tissue was trimmed from the sound tissue, each fraction was weighed, and the patulin concentration in the juice was assayed by thin layer chromatography. The quantity of patulin in the whole apples and in decayed tissues was calculated and these values were used to determine the percentage of total patulin removed by trimming. The patulin content ranged from 140 to 4880 mug/apple. Trimming removed 93-99% of the total patulin, regardless of incubation temperature, fungus strain, or apple variety. Trimming of defective tissue from fungus-rotted apples could substantially reduce the patulin concentration.

Food Contamination↗
PubMed1975

Predictive value of ultrasonically derived arterial pressure in determination of amputation level.

There is a real need for a reliable guide to determine the lowest level of successful limb amputation. Factors such as wound edge bleeding and clinical judgment cannot be minimized but, when clinical experience had been the sole index, AK amputation has too often resulted. The availability of a pocket-sized Doppler ultrasound pulse detector has made thigh or ankle systolic pressure recording a simple bedside procedure. Our analysis shows that a thigh pressure of 50 mm Hg correlates well with success of BK amputation. This fact can be added to the clinician's judgment in better rehabilitating the elderly ischemic amputee.

Aged↗