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Biomedical subjects

C Lauritzen

Publications and source records attributed to C Lauritzen.

At least 163 records · Page 9Linked to original sources

White blood cell deformability and plugging of skeletal muscle capillaries in hemorrhagic shock.

The cause of maldistributed capillary perfusion in hemorrhagic shock was investigated in a combined in vivo and in vitro study. The cat tenuissimus muscle was observed by vital microscopy before and after withdrawal of 45% of the blood volume. The induced shock conditions reduced the number of perfused capillaries about 50%. Close examination of the scattered, nonperfused capillaries showed that they remained open and almost invariably contained one or several leukocytes. These cells were usually located at the bulgings of endothelial cell nuclei, and when occasionally dislodged, recirculation immediately occurred. Platelet or erythrocyte aggregates were not seen in the microvasculature in shock. To test whether the trapping of leukocytes reflected an impaired deformability of these cells in shock or was merely a pressure dependent phenomenon, deformability studies were performed on leukocytes in vitro. Central venous blood was drawn before and 2 h after bleeding and leukocytes were separated by sedimentation. The passage-time of single leukocytes through a glass capillary stenosis at constant driving pressures was used as an index of cell deformability. No qualitative changes in stiffness were found after shock. The distribution of cell passage-times indicated, however, that the stiffest portion of the leukocyte population was removed from the circulation in shock.

Animals↗

Microvascular repair after the sleeve anastomosis. An ultrastructural study in the rat femoral vessels.

A microvascular sleeve anastomosis, inserting one vessel into another, using 3 extraluminal sutures, was performed on rat femoral vessels. In 21 arterial and 21 venous anastomoses the intimal healing and the vascular wall rebuilding were studied by scanning and transmission electron microscopy. The patency rate of the anastomoses was 21/21 in the arteries and 19/21 in the veins. Functional recovery of the endothelium took place within a week.

Animals↗

Long-term study of the microvascular sleeve anastomosis: an experimental study in the rabbit renal artery.

A long-term study of 5 sleeve anastomoses in rabbit renal arteries was performed. Six months postoperatively angiography, light microscopy and electron microscopy was carried out. Good long-term function of the anastomoses without any stenoses or aneurysm formation was obtained. It was concluded from this study in rabbits that the sleeve technique is suitable for microvascular anastomosis and that good long-term function can be obtained.

Animals↗

[Hormonal regulation and hormone therapy in childhood and adolescence. Part 2: Therapeutic problems (tall stature, amenorrhea, delayed puberty, oligomenorrhea, precocious puberty, anorexia nervosa, anisomastia, hypermastia, acne etc)].

The most important therapeutic problems of female puberty and adolescence are discussed, including high stature, amenorrhoea, oligomenorrhea, pubertas tarda, anovulation, anorexia, anisomastia, hypermastia. Indications for treatment are given and the possibilities for a prophylactic medicine in this age group are stressed.

Acne Vulgaris↗

[Hormonal regulation and hormone therapy in childhood and adolescence. Part 1: development of endocrine glands, hormone production, menarche and secondary sex characteristics].

The growth curves of the endocrine glands in female puberty are described. Adrenarche with an elevated production of adrenal dehydroepiandrosterone marks the beginning of prepuberty. By decrease of hypothalamic sensitivity to sexual steroids begins the deviation of FSH and LH levels. Significant increases of gonadotrophins and prolactin occur during sleep. There is a good correlation between bone age, Tanner-stages of breast and pubic hair development and steroid hormone levels. Criteria of maturity for young girls including menarche and ovulation are given.

Adolescent↗

Plasma concentrations of unconjugated and conjugated estrogens and gonadotrophins following application of various estrogen preparations after oophorectomy and in the menopause.

In 55 patients after oophorectomy and 20 women after natural menopause an oral estrogen replacement therapy was performed with estrone-sulfate, estradiol 17-valerate, estriol-succinate, a combination of micronized estradiol and estriol (Estrifam, Trisequens), and natural conjugated estrogens. In 4 patients a 3 mg estradiol per 5 g ointment substance was applied on the abdominal skin. The interindividual variations of estrogen increments during therapy were considerably high. Oral intake of 2 mg estriol-succinate daily was followed by a 500% increase of total (conjugated + unconjugated) estriol. Concentrations of unconjugated estrogens were not altered by this dosage. Following oral application of the other above mentioned preparations, prominent rises--especially of unconjugated estrogens in plasma--were noted. The concentration peaks occurred within 3--6 h after application. Unconjugated estradiol-17 beta in plasma was comparable with values of the follicular phase of a normal menstrual cycle, unconjugated estrone, however, was nonphysiologically high. Consequently, the E1/E2 ratio was greater than one whereas it is normally below one. 12 h after oral estrogen application, plasma estrogens dropped to almost initial values, so that a second medication seems to be necessary in order to guarantee an adequate supplementation over the course of the day. The hormone values determined in this study did not show significant differences between patients after a natural menopause and after oophorectomy. There was a positive correlation between rising estrogen levels and suppressed gonadotrophins during replacement therapy. The occurrence of climacteric symptoms did not exclusively depend on low estrogen and high gonadotrophin levels. Good tolerance of estrogen therapy with significantly elevated estrogen concentrations in plasma can be obtained transcutaneously in the form of estrogen ointments. Such therapy might simulate the physiological estrogen pattern even better than oral application does because of delayed and diluted steroid flow to the liver.

Castration↗

A technical and biomechanical comparison between two types of microvascular anastomoses. An experimental study in rats.

The microvascular sleeve anastomosis, where one vessel is inserted into the other, was compared with the conventional end to end anastomosis. In an experimental study in rat femoral arteries 42 anastomoses of each kind were examined. Operating time, patency rates, flow rates and strength of the anastomoses were recorded at various postoperative time intervals. It is concluded that the sleeve anastomosis is quicker to perform and that the two types of anastomoses in biomechanical respects are similar. Flow rates are slightly decreased immediately postoperatively in the sleeve anastomosis but this is of a temporary nature.

Animals↗

The sleeve anastomosis in clinical microsurgery. Case report.

Clinical use of the microvascular sleeve anastomosis in 6 elective free tissue transfers is reported. Arterial and venous anastomoses were performed. It was found that with the exception of the distal anastomosis of a vein graft to artery the sleeve anastomosis was simple and efficient. It was concluded that when the vessels to be anastomosed have suitable length and diameter the sleeve anastomosis may well be used. By its use time and effort can be saved, especially in cases requiring multiple anastomoses.

Adult↗

[Favorable effects of estrogens and progesterones on general diseases].

Estrogens and progestagens exert positive effects on some general diseases as iron deficiency, anemia, premenstrual syndrome, intermenstrual migraine, akne, seborrhoea, hirsutism, androgenetic alopecia, slerodermia, rheumatoid arthritis, osteoporosis and depressive disorders. The mechanism of action and the mode of treatment in such cases are discussed.

Acne Vulgaris↗