Biomedical subjects

M Beausang-Linder

Publications and source records attributed to M Beausang-Linder.

8 recordsLinked to original sources

PubMed1992

Expression of platelet-derived growth factor and its receptors in proliferative disorders of fibroblastic origin.

Platelet-derived growth factor (PDGF) is known to stimulate the proliferation of connective tissue-derived cells in vitro. Less is known about its functions in vivo, and the role of PDGF in the development of human tumors has not been clarified. The authors have investigated the occurrence of PDGF and PDGF receptors in a series of proliferative disorders of fibroblastic origin using immunohistochemical and in situ hybridization techniques. High expression of PDGF beta-receptor mRNA and protein was found in the malignant tumors, and also in some benign lesions, such as dermatofibroma. In all these cases, benign as well as malignant, the PDGF B-chain mRNA, and less clearly, the PDGF A-chain mRNA, were coexpressed with the beta-receptor. In contrast, high expression of PDGF alpha-receptor mRNA was only found in fully malignant lesions, i.e., malignant fibrous histiocytoma. These data indicate that an autocrine growth stimulation via the PDGF beta-receptor could occur in an early phase of tumorigenesis, and may be a necessary but insufficient event for the progression into fully malignant human connective tissue lesions.

Alcian Blue↗

PubMed1990

The effect on the preoperative symptoms and the late results of Skoog's reduction mammaplasty. A follow-up study on 149 patients.

A retrospective study has been carried out on 149 patients with hypertrophic breasts operated on during the period 1977 to 1979 using Skoog's technique of reduction mammaplasty. Both physical and psychological symptoms were investigated as well as the follow-up results of the operation as a whole, as judged by the patient herself. The observation time was 5 years and the average age of the patients was 39 years. 75% of the women were overweight or obese. The symptoms the middle-aged women indicated preoperatively to be caused by the hypertrophic breasts were pain in the neck, shoulders and back regions, and indenting bra straps, while psychological and cosmetic reasons were more common in younger women. The average reduction per breast was 1,100 g with 3,800 g as the largest total reduction. There was a positive correlation between the age of the patient and the tissue reduction, and a significant correlation between overweight and the amount of tissue reduced. Complications were more often seen when more than 1,500 g mammary tissue were removed or when the operation time exceeded 3.5 h. Infections, nipple necroses and pronounced scars were also positively correlated to overweight. The preoperative symptoms were cured or improved to 80-100%. 95.3% of the women were very satisfied (65.1%) or satisfied (30.2%) with the follow-up results while only 4.7% considered the results to be less satisfactory.

Breast↗

PubMed1982

Sympathetic effects on cerebral and ocular blood flow in rabbits pretreated with indomethacin.

The effects of unilateral stimulation of the cervical sympathetic chain on cerebral and ocular blood flow was investigated in 8 rabbits anesthetized with pentobarbital sodium and pretreated with indomethacin in order to inhibit the formation of prostaglandins. Blood flow determinations were made with the labelled microsphere method during normotension and acute arterial hypertension. Hypertension was induced by ligation of the thoracic aorta. Evans blue was given as a tracer for protein leakage during hypertension. Sympathetic stimulation had no significant effect on the blood flow in the brain under the two conditions studied. In the uvea marked effects of sympathetic stimulation were obtained at normotension as well as at hypertension. There were no indications of breakdown of the blood-brain barrier or the blood-aqueous barrier. Thus, there was no evidence for any prostaglandin-mediated inhibition of sympathetic effects in the brain or the eye.

Animals↗

PubMed1982

Effects of sympathetic stimulation on cerebral and ocular blood flow. Modification by hypertension, hypercapnia, acetazolamide, PGI2 and papaverine.

The effect of unilateral, electrical stimulation of the cervical sympathetic chain in rabbits anesthetized with pentobarbital sodium and vasodilated by hypercapnia, acetazolamide, papaverine or PGI2 was investigated to determine to what extent the sympathetic nerves to the brain and the eye cause vasoconstriction and prevent overperfusion in previously vasodilated animals. Evans blue was given as a tracer for protein leakage. Blood flow determinations were made with the labelled microsphere method during normotension and acute arterial hypertension. Hypertension was induced by ligation of the thoracic aorta and in some animals metaraminol or angiotensin was also used. Acetazolamide caused a two to threefold increase in cerebral blood flow (CBF) and hypercapnia resulted in a fivefold increase. CBF was not markedly affected by papaverine or PGI2. In the choroid plexus, the ciliary body and choroid, papaverine and hypercapnia caused significant blood flow increases on the control side. Sympathetic stimulation induced a 12% blood flow reduction in the brain in normotensive, hypercapnic animals. Marked effects of sympathetic stimulation at normotension were obtained under all conditions in the eye. In the hypertensive state the CBF reduction during sympathetic stimulation was moderate, but highly significant in hypercapnic or papaverine-treated animals as well as in controls. Leakage of Evans blue was more frequently seen on the nonstimulated side of the brain. In the eye there was leakage only on the control side except in PGI2-treated animals where 2 rabbits had bilateral leakage. The effect of sympathetic stimulation on the blood flow in the cerebrum and cerebellum in vasodilated animals seems to be small or absent if the blood pressure is normal. In the eye pronounced vasoconstriction occurs under these conditions. In acute arterial hypertension sympathetic stimulation protects both the cerebral and ocular barriers even under conditions of marked vasodilation.

Acetazolamide↗

PubMed1981

Cerebral circulation in acute arterial hypertension--protective effects of sympathetic nervous activity.

The cervical sympathetic chain was stimulated electrically at 6 or 3 Hz on one side in anesthetized cats. Acute arterial hypertension was induced by ligation of the aorta. Evans blue was given as tracer for protein leakage. The regional blood flow in the brain was determined by using labelled microspheres. At high blood pressures there was a multifocal breakdown of the blood-brain barrier. The regions with breakdown had 10-20 times the normal flow rates. With a maintained hypertension regions which were overperfused at 5 min were still overperfused at 10 min, but there was little addition of new overperfused areas. Normalization of the pressure resulted in almost twice the normal flow rates in previously overperfused regions. The breakdown of the blood-brain barrier was restricted to the non-stimulated side, or more marked on that side. The protective effect of the sympathetic stimulation lasted more than 10 min. The results indicate that acute arterial hypertension tends to cause forced and long-lasting vasodilation in some areas in the brain but regions which are resistant to the acute rise have an increase in the vascular tone. Sympathetic activity helps in developing this tone. Normalization of the blood pressure results in partial recovery of the vascular tone in previously overperfused regions and normalization in other areas.

Acute Disease↗

PubMed1980

Early effects of cervical sympathetic stimulation on cerebral, ocular and cochlear blood flow.

Autoregulatory mechanisms may be expected to modify effects of vasomotor nerve stimulation in many tissues. Attempts were made to reveal a distinct early, but transient effect of cervical sympathetic stimulation on cerebral, retinal and cochlear blood flow. The labelled microsphere method was used to determine regional blood flow during electrical stimulation of the cervical sympathetic chain for 15-25 s and 5 min. At a frequency of 6 Hz there was 5% reduction in cerebral flow at 15-25 s and 7% at 5 min. In the choroid plexus the mean reduction was 22% at 15-25 s but decreased 10% after 5 min. In the cerebellum, optic nerve and retina, sympathetic stimulation had no appreciable effect on the blood flow. In the cochlea and iris, the blood flow reductions were 25 and 32%, respectively, on both occasions. In the choroid, vasoconstriction increased with time, whereas in the masseter muscle there was a decrease. Thus in the present experiments no indication was found of an autoregulatory escape phenomenon in the brain, the eye or the cochlea. Some escape was noted in the masseter muscle.

Animals↗

PubMed1979

Noise and cochlear blood flow.

The effect of noise after unilateral transection of the cervical sympathetic trunk on cochlear blood flow was studied in anesthetized cats. The sound pressure level was 100 dB and the exposure time 6 min. Neither noise nor sympathectomy were found to affect the blood flow.

Animals↗

PubMed1979

The cochlear blood flow in relation to noise and cervical sympathectomy.

The effect of noise and unilateral transection of the cervical sympathetic trunk on cochlear blood flow was studied in anesthetized cats. The sound pressure level was 100 dB and the exposure time 6 min. Neither noise nor sympathectomy were found to affect the blood flow.

Acidosis, Respiratory↗