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Biomedical subjects

N Hartmann

Publications and source records attributed to N Hartmann.

At least 19 recordsLinked to original sources
PubMed1992

Pleiotrophin stimulates fibroblasts and endothelial and epithelial cells and is expressed in human cancer.

Previously we reported the purification of the heparin-binding growth factor pleiotrophin (PTN) from supernatants of the human breast cancer cell line MDA-MB-231. To investigate further the biological activities of PTN and its potential role in cancer, we cloned a PTN cDNA and expressed the gene in a human kidney and in a human adrenal carcinoma cell line (SW-13). The supernatants harvested from cells transfected with PTN contained a heparin-binding specific protein of an apparent molecular mass of 18 kDa. These supernatants stimulated the proliferation of endothelial cells as well as the anchorage-independent growth of SW-13 cells and of normal rat kidney fibroblasts. Furthermore, SW-13 cells transfected with PTN acquired autonomous growth in soft agar and were tumorigenic in athymic nude mice. In contrast to these results with PTN from human cells, PTN obtained from insect cells (Sf9) using recombinant baculovirus as a vector was biologically inactive. We detected high levels of PTN mRNA in 16 of 27 primary human breast cancer samples (62%) as well as in 8 of 8 carcinogen-induced rat mammary tumors. Furthermore, 9 of 34 human tumor cell lines of different origin showed detectable PTN mRNA. We conclude that PTN may function as a tumor growth and angiogenesis factor in addition to its role during embryonic development.

Adrenal Gland Neoplasms↗
PubMed1990

Does isoflurane lead to a higher incidence of myocardial infarction and perioperative death than enflurane in coronary artery surgery? A clinical study of 1178 patients.

To examine if the choice of volatile agents influences cardiac outcome in coronary artery surgery, 1178 patients undergoing elective coronary artery bypass grafting without additional operations received enflurane (608) or isoflurane (570) as their primary anesthetics. The inspired concentration of volatile agent (administered with 50% nitrous oxide) was adjusted depending on the level of blood pressure at the discretion of the anesthesiologist. In addition to the volatile agent assigned, each patient received small doses of fentanyl at induction and before sternotomy (total 0.006-0.008 mg/kg). The groups did not differ in preoperative and surgical characteristics except for a more frequent history of renal dysfunction in patients given isoflurane. The rates of postoperative myocardial infarction, administration of positive inotropic agents at the time of weaning from cardiopulmonary bypass, and in-hospital deaths in the enflurane and isoflurane groups were 1.8% and 4.0% (P less than 0.05), 4.9% and 8.1% (P less than 0.05%), and 0.3% and 2.1% (P less than 0.01), respectively. Although the mechanism of the adverse effects of isoflurane could not be clarified in this study, these results demonstrate that the use of isoflurane could be inappropriate in patients undergoing coronary artery bypass grafting.

Aged↗
PubMed1979

[Effect of diet and L-thyroxine on deiodination of L-thyroxine in rat liver].

Male Wistar rats on 3 or 50% fat diet for 14 weeks were treated during 6 weeks with L-thyroxine (5 or 25 or 50 microgram 100 g body weight/2 times weekly, sc.) and the activity of L-thyroxine-deiodinase was determined in supernatans of liver homogenates. With increasing thyroxine lading the deiodinating activity increases statistically significantly within each diet group. The liver of animals on 50% fat diet deiodinates increasing thyroxine doses to a lesser extent than livers of animals on 3% fat diet. It is discussed that high fat diet influences thyroid function and that thyroxine shares effectiveness and undergoes deiodination also in other tissues, probably in fat tissue, to a higher extent.

Animals↗
PubMed1979

[T4 metabolism in age matched heavy and light rats with good and bad feed efficiency following high- or low-in-fat diet].

Rats, fed two diets (high or low in fat content), were at the and of the feeding-period separated in light and in heavy animal groups. The leaner rats from the diet group high in fat content show opposite to the heavier animals of this diet group significantly increased T4 distribution spaces, significantly shortened T4 half life time and lower feed efficiency. T4 serum values, absolute T4 degradation per day and body mass and free thyroxine index in these leaner rats also increased significantly. However comparing heavy rats feed a diet low and light rats fed a diet high in rat content the latter show also a decreased feed efficiency, but no differences in T4 serum concentration or T3 binding capacity of serum proteins, free thyroxine index and T4 degradation. The results in T4 metabolism are discussed in relation to feed efficiency of the investigated animal groups.

Animals↗
PubMed1979

[Iodoamino acid distribution and weight of the thyroid gland, T4 serum level and T4 metabolism in relation to diet, body fat content and age of rats].

Rats were rendered obese by feeding them a fatty diet (HFD, fat: 50% of weight). At the end of the experimental period the animals were divided, also the control rats, which were fed a low-fat diet (LFD, fat: 3% of weight), in light and heavy weight groups. The heavy and obese HFD groups showed, unlike the light LFD-animals, equal absolute but significantly lower relative thyroidal weights. The absolute thyroidal weights of light and heavy animal groups, which received in each case the same diet, were identical, the relative thyroidal weights of the heavy rats on the other hand decreased significantly. The iodoamino acid distribution in the thyroid of rats showed no variation in animals fed various diets and differed in body mass and fat content. The T4 serum levels of the HFD-, in comparison to the LFD-animals increased significantly. Between light and heavy animals in equal diet groups no differences were obtained for the T4 serum values. The serum T3 levels of LFD- and HFD-rats were also equal. The heavy HFD- showed in comparison to the light LFD-animals a significantly lower T4 clearance and in the higher age groups a significantly extended T4 half-life time. The HFD- and LFD-rats with approximately equal body mass and body fat content showed no differences in T4 half-life time and T4 clearance rate depending on diet. A relation between higher body fat content and increased serum T4 levels as a possible adaption to obesity in heavy HFD-rats is discussed. By the comparison of younger and older rats in the most investigated diet and weight groups the older animals showed a decreasing tendency for K and TD/100 g KM and a significant decrease in the clearance rate and in the TD for T4, related to body mass. An influence of diet, body mass or fat content on the decrease of the T4 metabolism of rats with increased age is not evident. The T4 serum levels were not different in dependence on age, but the free T4 serum level was significantly lower in the older rats.

Adipose Tissue↗
PubMed1978

[Heart trauma caused by central venous catheter (author's transl)].

Four cases of extensive traumatic lesions of the right atrium induced by central venous catheter, are reported. In one case there was beginning in the other complete perforation of the right atrium. Such lesions can be caused by horizontal fixation of the intracardiac portion of a catheter due to wall-adherent thrombi; catheters held near the coronary sinus by a so-called Chiari net; or by coiling of the catheter within the atrium. Central venous catheters often cause endothelial lesions and thrombotic changes in the veins near the heart. Possible trauma to the right atrium, which could provoke fatal complications (e. g. haemopericardium or arrhythmias) must, therefore, be given special attention.

Adult↗
PubMed1978

[Properties of adipocytes (diameter, volume, triglyceride content, cell number) of certain types of fatty tissue as a function of age in male Wistar rats].

The diameter, volume, triglyceride content and number of adipocytes were determined in male Wistar rats at the age of 6 weeks and 2, 3, 12 and 18 months, respectively. A standard diet and water were given ad libitum. The adipocytes were isolated by means of the method of RODBELL. The weight and fat content of the fatty tissues were determined gravimetrically. Age exerts no effect on the adipocyte parameter, nor on the weight and the fat content of the fatty tissue. In contrast to this, there are relationships between adipocyte diameter and the increases in body weight. In all age groups, the increase in size and number of the adipocytes was significantly greater in heavy animals than in light ones. Genetic, hormonal and dietarily-induced factors are discussed as a possible cause. The authors observed no difference in adipocyte size between epididymal and perirenal fatty tissues. As compared to this, the mesenteric adipocytes were smaller.

Adipose Tissue↗
PubMed1978

[Effect of a high fat diet on the behavior of the diameter, volume, triglyceride content and number of the adipocytes in different types of fatty tissues in male Wistar rats].

The effect of a high-fat diet on the diameter, volume, triglyceride content and number of the adipocytes was studied in male Wistar rats at the age of 9 weeks and 6 months, respectively. The adipocytes were isolated by means of the method of RODBELL. The adipocyte diameters were measured using the microscopic method. The weight and the fat content of the fatty tissue were determined gravimetrically. A diet containing 50% fat increases the diameter, volume and triglyceride content of the adipocytes and also the weight and the fat content of the different types of fatty tissue. The fat content of the diet and the duration of feeding are of importance. The high-fat diet exerts no effect on the adipocyte number. However, in both age groups, the adipocyte numbers were sometimes greater in heavy animals than in light ones fed the same diet. Genetic, hormonal, and dietarily-induced factors are considered as a possible cause.

Adipose Tissue↗
PubMed1978

[Dietary proteins and deiodination in the liver].

The authors studied in male Wistar rats the effects of diets containing 66 and 2% (w/w) of protein on the one hand, and 18% (w/w) of protein on the other hand, on the deiodination of L-thyroxine in liver homogenate supernatants. The deiodase activity in the liver protein increased in case of low-protein diet, and decreased in case of high-protein diet; these differences were statistically significant. When the body weights of the animals were taken into account, the deiodinating power of the whole liver was significantly reduced in case of low-protein diet, but not significantly reduced in case of high-protein diet. Consequently, the reference value adopted for the calculation of the degree of deiodination is of paramount importance to validity.

Animals↗
PubMed1978

[Effect of diet and thyroxine on body composition in rats].

In young male Wistar rats the influence of different fat content of the diet (7 or 25 or 50 weight percent of fat) and of thyroxine (5 or 50 microgram/100 g body mass, 2 times/week, sc.) on body composition was investigated by carcass analysis. After high doses of thyroxine the percentage body fat decreases and protein and water content increases within the same diet group (7 or 25 or 50% fat diet). Smaller doses of thyroxine have only the same effect as high thyroxine doses in the 7% fat diet group; the body composition is unchanged in the 25% fat diet group, and in rats after 50% fat diet thyroxine even brings about an increase in body fat. It is concluded that the fat content of the diet makes thyroxine partly ineffective. A comparison of the different diet groups, also with or without thyroxine treatment, brings the result of significantly increased percentage body fat after 25 and 50% fat diet; body protein and body water decreases respectively. It appears from the present study that controversial results in literature concerning body composition after thyroxine treatment, may be caused by different diets, especially the fat content of the diets.

Animals↗
PubMed1978

[Uptake of utilizable food energy by light-weight and heavy-weight rats fed a low-fat or high-fat diet].

The uptake of utilizable dietary energy (DE) as affected by diet (containing 3 or 50% (w/w)fat), body mass (BM) and age was investigated in male Wistar rats. In comparing heavy-weight animals fed the high-fat diet (HFD) with light-weight animals fed the low-fat diet (LFD) (differences in BM up to 60%), it was found that the uptakes of DE calculated on animal were significantly higher (up to 55%) in the HFD animals than in the LFD animals; but there were no significant differences when the uptakes of DE were calculated on 100 g BM. Thus, the LFD rats (the diet of which contained a high proportion of protein (70% (w/w)) exhibited no reduced uptakes of utilizable DE as compared to HFD rats. Of the heavy-weight LFD animals and the light-weight HFD animals which showed virtually no differences in BM, the HFD animals take up more utilizable DE (per animal or per 100 g BM) than the LFD animals. This difference, which amounts to 60%, is statistically significant. The comparison of the uptakes of DE/animal/100 g BM by light-weight rats with those by heavy-weight rats fed the same diet showed that the uptakes by the heavy-weight animals were in most cases significantly greater. Consequently, the greater BM of the heavy-weight animals of the respective diet groups must be attributed to more efficient utilization of feed. This is also indicated by the fact that the light-weight HFD animals excret more fat in the faeces than the heavy-weight animals. The amount of fat excreted by the HFD animals is some 10-fold greater than that excreted by the LFD animals. However, when the amount of excreted fat is expressed in % of ingested dietary fat, the fat excretion is of the same order of magnitude on both diets.

Aging↗
PubMed1978

[Changed body composition by increased total body fat content in experimentally hypothyroid rats].

Total body fat content was determined in growing normal male Wistar rats and hypothyroidized animals 7 weeks after feeding with Methimazol (group MMI-HT), Methyl-thiouracil (group MTU-HT), and performance of radiothyroidectomy by 131-iodine (group R-HT), respectively. At the end of experiments there was an extreme hypothyroid state in all treated groups, verified by external signs, growth kinetics, serum cholesterol estimation and evaluation of the iodothyrosine pattern of the thyroid glands. Changed body composition resulted in all HT-groups from significant increase of total body fat content. The relation of constituents fat : protein : water of 1 : 2 : 6 in the KT-group was changed into 1 : 1 : 3 in the HT-groups. No differences were found between the different HT-groups. Our findings are in good agreement with altered metabolism of plasma lipids described by other authors showing the existence of a highly disturbed lipid metabolism in thyroid hormone deficiency.

Animals↗
PubMed1977

[Effects of two special diets on the body weight of rats].

The authors studied the effects of 2 special diets on the weight behaviour of male Wistar rats (aged 4--5 weeks) from Schönerlinde near Berlin up to the age of 35 weeks. The weight behaviour of rats fed a standard diet (commercially available pellets) lies between those of the experimental rats and near that of the rats on low-fat (3%) diet. The one special diet that contains 3% of fat is low-fat (8.4% of the gross energy of the feed) and high-protein (69.3% of the gross energy); the other diet that contains 50% of fat is high-fat (76% of the gross energy). The two diets (containing 331 and 612 kcal/100 g, respectively) are not isocaloric but the animals on the low-fat diet ate twice as much as the animals on the high-fat diet. The rats on the high-protein low-fat diet were prone to copious sweating. It was generally noticed that the animals on the high-fat diet became to a greater extent hypokinetic with increasing age. The weight difference between the two dietary groups increased with increasing age, reaching its maximum value (77%) at the age of 24 weeks and then decreasing to 60% (at the age of 35 weeks). Up to the age of 12 weeks, the rats are in the more "dynamic" phase of weight increase; and from the 16th week, in the more "static" phase of weight increase.

Aging↗
PubMed1977

[Effect of protein content and thyroid hormone on body composition in growing rats].

The effects of an isocaloric control diet of high-protein and low-protein diets (in which protein amounted to 16, 62 and 2% of total calorie content, respectively) with and without simultaneous administration of Thyreotom or methylthiouracil on total body composition have been studied in growing male Wistar rats. In spite of higher average Kcal intake (per day and 100 g of body weight), the rats on the high-protein diet were weighing less than the control animals at the end of the experiment. As compared to the control animals, the rats on the high-protein diet as well as those on the low-protein diet showed a greater relative weight of the thyroid gland. The protein percentage of the body was not significantly increased by an increase in protein supply; likewise, it was not significantly reduced by a decrease in protein supply. The body fat content was by 2/3 lower in the rats on the lowprotein diet than in the control animals. This difference was statistically significant. Thyroid hormones (1 mug liothyronine + 4 mug levothyroxine/100 g body weight, administered orally for 3 weeks) produced a slight increase of body protein in the rats on the high-protein diet; they increased it significantly in the rats on the low-protein diet. Body fat was correspondingly reduced. Methylthiouracil reduces the body fat content in the control animals and in the rats on the high-protein diet; it increased the body fat content in the rats on the low-protein diet. Our results confirm the partial findings of human pathology and demonstrate clearly that nutritional diseases, especially protein deficiency, worsen considerably in case of concomitant disorders of thyroid hormone metabolism.

Animals↗