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Biomedical subjects

P Hahn

Publications and source records attributed to P Hahn.

At least 145 records · Page 8Linked to original sources
PubMed1981

The effect of starvation on obese mice.

Plasma level of total and acylcarnitine and the activities of carnitine acetyltransferase (CAT) and carnitine palmitoyltransferase (PCT) in liver and CAT in brown fat were determined in young obese (ob/ob) mice and their littermates during starvation. Plasma levels of acylcarnitine and beta-hydroxybutyrate rose equally in both groups. Total carnitine levels, however, decreased in lean and rose in obese animals. Hepatic PCT and phosphoenolpyruvate carboxykinase activities rose more in lean than obese mice and brown fat CAT activity decreased in the obese group. Fatty acid synthetase activity decreased equally in the liver in obese mice and their lean littermates.

Animals↗
PubMed1980

Effect of insulin and prednisolone on cyclic nucleotides and phosphoenolpyruvate carboxykinase activity in brown fat and liver of developing rats.

The concentrations of cyclic AMP and cyclic GMP in brown fat and liver of both suckling and adult rats at fixed times after injection of insulin (2.5 U/100 g body weight) or prednisolone (2.5 mg/100 g body weight) were compared with the activity of phosphoenolpyruvate carboxykinase assayed 24 h after the injections. A stimulus that produced an increase in cyclic AMP content also produced an increase in the enzyme activity. If the content of cyclic GMP was also increased there was no rise in phosphoenolpyruvate carboxykinase activity. A rise in the content of cyclic GMP alone was associated with a reduction in the activity of the enzyme. These preliminary results indicate that cyclic AMP could be involved in the induction of phosphoenolpyruvate carboxykinase and that cyclic GMP may somehow be related to its repression. The known differences in the response of phosphoenolpyruvate carboxykinase activity to insulin and prednisolone in different tissues and at different stages of ontogenic development may thus be linked to differences in the responsiveness of enzymes concerned with the metabolism of cyclic nucleotides.

Adipose Tissue, Brown↗
PubMed1980

The response of cyclic nucleotide content in liver and brown fat of rats weaned to different diets.

Rats were weaned on the 18th or 30th postnatal day to a high-fat, high-carbohydrate or atherogenic diet. Twenty-four hours later, hepatic levels of cyclic guanosine 3',5'-monophosphate (cyclic GMP) and adenosine, 3',5'-cyclic monophosphate (cyclic AMP) were found to be higher in male animals aged 31 days fed the high-fat than those fed the high-carbohydrate diet. Prematurely weaned rats (day 18) reacted in the same way. However, feeding either diet resulted in higher hepatic cyclic nucleotide levels than found in rats kept with the dam. The atherogenic diet was least effective in raising these levels. After a 24-hour fast, cyclic nucleotide levels in liver and brown fat were elevated and hepatic levels could not be lowered by 6 hours of feeding the high-fat or atherogenic diet. In male 40-day-old rats, however, feeding for 2 hours was sufficient to lower these levels, more so with a high-carbohydrate than a high-fat diet. Since blood levels of glucagon are high, and those of insulin are low in 18-day-old rats that are not weaned and since their hepatic cyclic nucleotide levels are low, it is suggested that other factors, in addition to blood hormone levels, play a role in regulating cyclic nucleotide levels.

Adipose Tissue, Brown↗
PubMed1980

Cholesterol metabolism in obese mice.

Young male obese mice and their lean litter mates (strain ob/ob) were compared. Serum cholesterol levels were higher in obese than in lean animals. 3-Hydroxy-3-methylglutaryl-CoA reductase activity was lower in brown adipose tissue and liver of obese mice than in tissue from their lean litter mates. However, activity of this enzyme was found to be the same or higher in white adipose tissue of obese animals than in their lean litter mates. During complete starvation, blood cholesterol levels in obese mice decreased and attained the lower level of lean ones after 48 h. After 24 h of starvation, enzyme activity decreased in white fat of obese mice only. Simple calculations indicate that white fat from obese mice produces about fourfold more cholesterol per day per unit body weight than does the same tissue from lean mice.

Adipose Tissue↗
PubMed1980

Carnitine acetyltransferase in developing mammals.

Carnitine acetyltransferase (CAT) activity was determined in mitochondria and microsomes of liver and brown adipose tissue in fetal and postnatal rats, rabbits and guinea pigs. In rat liver and brown adipose tissue, mitochondrial CAT activity increased perinatally. Microsomal CAT activity also increased in brown adipose tissue. In liver, however, a rise was first noted after the 20th postnatal day. The ratio of mitochondrial to microsomal activity was higher in brown fat than liver throughout the period studied. Absolute values for both were always much higher in brown adipose tissue than in liver. Catalase activity (an enzyme localized in the peroxisomes) in rat liver increased after day 20 while in brown adipose tissue it attained a peak at 7 days after birth. At all times, hepatic activity exceeded activity in brown adipose tissue. The ratio on day 30 was 1 (brown adipose tissue) to 25 (liver). In both guinea pigs and rabbits, hepatic mitochondrial CAT activity was 10- to 20-fold higher than in the rat already prenatally. Microsomal activity, on the other hand, was approximately the same in all three species. It is concluded that probably only the mitochondrial CAT is directly related to fatty acid oxidation. The role of microsomal enzyme remains unclear.

Acetyltransferases↗
PubMed1980

Combination of clinical examination, mammography and aspiration cytology in the diagnosis of carcinoma of the breast (179 cases).

In 179 histologically confirmed cases of carcinoma of the breast the diagnostic values of clinical examination, mammography and aspiration biopsy were compared. The effect of combining these three diagnostic methods was evaluated. Clinical examination and mammography each produced a positive diagnosis in 89% of the cases, and in 88% aspiration biopsy. A combination of these three methods enabled a positive diagnosis of carcinoma of the breast in 99% of the cases. Fine needle biopsy and mammography carried out by the clinician seem to be as effective as when done by the cytologist and diagnostic radiologist. A combination of clinical examination, mammography and aspiration biopsy increases the diagnostic accuracy of breast cancer.

Adult↗
PubMed1979

The value of whole body bone scan in the pre-operative assessment in carcinoma of the breast.

In 126 patients with primary breast cancer a patient moving whole body bone scan was performed when they first presented. None of the patients in stage I had an evidence of skeletal metastases. Two patients (3%) of 62 in stage II and 4 patients (17%) in stage III had evidence of skeletal metastases. It appears that whole body scanning is the most accurate, sensitive and convenient method of detecting osseous metastases and of staging breast cancer. This investigation should be carried out pre-operatively. Detection of early asymptomatic bony metastases will provide a better planning of treatment with rational approach.

Bone Neoplasms↗
PubMed1979

Plasma carnitine levels during intravenous feeding of the neonate.

The premature infant has a limited capacity for fatty acid oxidation. This study shows that solutions commonly used for intravenous feedings in the newborn infant contain no carnitine. Infants maintained on this solution have significantly lower total, free, and acylcarnitine levels as compared to when they are fed orally with expressed human milk or a proprietary formula, which is known to contain carnitine. The exogenous supply of carnitine to the premature infant may have a significant influence on the ability to stimulate optimal fatty acid oxidation.

Amino Acids↗
PubMed1979

Hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase response to litter size in suckling rats.

Rats were raised in litters of 3 or 14 from the 3rd postnatal day. Already, 2 days later on day 5, those raised in groups of three had elevated blood cholesterol and insulin levels and a very much lower hepatic 3-hydroxy-3-methyl-glutaryl-CoA (HMG) CoA) reductase activity, than the other group. When aged 40 days, hepatic HMG CoA reductase activity was higher in the group raised three rats per litter than in the large litter group.

Aging↗
PubMed1979

The response of adult rats weaned prematurely and normally to starvation.

Male rats were weaned normally (NW; day 30 after birth) or prematurely (PW; day 18) to a Purina Chow diet. Serum cholesterol levels and the activities of some enzymes of fatty acid and glucose metabolism were determined when the animals were 6 and 10 months old and, in the older group, also after 2 days of starvation. Blood cholesterol levels rose with age and at 10 months were higher in PW than NW rats. This difference disappeared after starvation. Hepatic pyruvate kinase (PK) activity was the same in fed NW and PW animals but was significantly higher in starved PW than NW rats. Hepatic phosphoenolpyruvate carboxykinase (PEPcK) activity was lower in NW than in PW rats, but this difference disappeared on starvation. In white fat, starvation caused a fall in PEPcK activity in both groups. In general, the effect of starvation did not accentuate the differences between the two groups. However, PEPcK activity in white fat increased with age about fourfold.

Adipose Tissue↗
PubMed1979

Acetylcarnitine and free carnitine in body fluids before and after birth.

The acetylcarnitine concentration in amniotic fluid fell significantly between 33 and 37 and 40 weeks of gestation. It was significantly higher in samples that had a low lecithin to sphingomyelin ratio. The acetylcarnitine content of tracheal fluid was higher in samples obtained from premature newborns. The major excretory form of carnitine is the acetate ester and only in adults does the urine contain significant amounts of free carnitine. The level of acetylcarnitine in plasma significantly increases after the first day of life; there was no difference in the plasma levels of carnitine between full-term and premature newborns. Plasma-free carnitine and acetylcarnitine levels were significantly lower in infants who were receiving a soybean-based formula. A positive correlation was found between the plasma level of ketone bodies and that of acetylcarnitine.

Acetylcarnitine↗
PubMed1979

Efficiency of postoperative radiation in carcinoma of the breast. A comparison between two methods.

The results of simple mastectomy and postoperative irradiation of the chest wall and the regional lymph nodes in a series of 256 patients with primary carcinoma of the breast (between 1970 and 1972) were compared with those in a series of 155 patients (from 1963 to 1965) treated with radical mastectomy and postoperative irradiation of the regional lymph nodes. A statistically significant difference (p less than 0.01) was found between the chest wall recurrences in the group of patients with irradiation of the chest wall and the group without. No evidence indicates that routine postoperative irradiation should be harmful. Distant metastases in the 1970--1972 group were less frequent (13%) than in the 1963--1965 group (29%)9 The age-corrected 4-year survival rates for stages I and II were 83 per cent for the 1970--1972 group and 78 for the 1963--1965 group. The age-corrected 10-year survival rates for states I and II were 60 per cent.

Age Factors↗
PubMed1978

Control of phosphoenolpyruvate carboxykinase in brown adipose tissue of infant rats.

Activity of phosphoenolpyruvate carboxykinase (PEPK) in brown adipose tissue (BAT) of infant rats is high and is depressed by a single injection of corti-costeroid or insulin. Both hormones inhibit synthesis of the enzyme in BAT and increase it in liver. Fatty acid synthetase activity is enhanced by these hormones, but only in BAT. It is suggested that corticosteroids may act via insulin release, since both blood glucose and blood insulin levels rise after steroid injection. The difference in response between BAT and liver is ascribed to the difference in adenyl cyclase response in the two tissues.

Adipose Tissue, Brown↗