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Biomedical subjects

J Lundberg

Publications and source records attributed to J Lundberg.

At least 55 records · Page 3Linked to original sources
PubMed1989

Direct evidence of active sympathetic vasodilatation in the skin of the human foot.

1. During operative aorto-femoral vascular reconstructions on sixteen patients, the sympathetic chain was stimulated electrically between the L2 and L4 ganglia while blood flow was monitored by laser doppler flowmeters from the skin on the sole of the foot and the ankle and by an electromagnetic flowmeter from the deep femoral artery. Epidural anaesthesia to at least the T6 level was used which excluded reflex effects. 2. Stimulation (10 Hz) at 1-12 mA current strengths for 30 s evoked both reductions and increases of blood flow in glabrous and hairy skin. Initial short-lasting flow increases (durations 9-19 s) followed by sustained decreases were common: sometimes there were sustained flow increases at low and decreases at high current strengths. 3. In the deep femoral artery (supplying predominantly muscle) only flow reductions were evoked. 4. The results provide evidence for sympathetically mediated vasodilatation in the skin of the human foot whereas leg muscles may be supplied by vasoconstrictor nerves only.

Aged↗
PubMed1987

Hemodynamic effects of dopamine during thoracic epidural analgesia in man.

The cardiovascular effects of dopamine were studied before and during thoracic epidural analgesia (TEA) in eight patients prior to abdominal aortic surgery. Dopamine was infused at rates of 2, 4, and 8 micrograms X kg-1 X min-1. Mean plasma dopamine concentration increased proportionally to the infusion rate. Before TEA, dopamine 8 micrograms X kg-1 X min-1 decreased systemic vascular resistance 4 +/- 4 mmHg min X 1-1 (m +/- SD) (P less than 0.05), but increased mean arterial pressure 15 +/- 12 mmHg (P less than 0.01), cardiac output 1.9 +/- 1.0 1 X min-1 (P less than 0.01), heart rate 10 +/- 9 beats X min-1 (P less than 0.05), and plasma norepinephrine concentration 544 +/- 252 pg X ml-1 (P less than 0.01). After the induction of TEA, which extended above the T2 dermatome and below the L2 dermatome, saline and albumin were infused to maintain central venous and pulmonary capillary wedge pressures. TEA reduced mean arterial pressure from 96 +/- 18 to 55 +/- 8 mmHg (P less than 0.01), cardiac output from 4.7 +/- 0.9 to 3.9 +/- 0.9 1 X min-1 (P = 0.05), systemic vascular resistance from 21 +/- 6 to 14 +/- 3 mmHg min X 1-1 (P less than 0.05), and plasma norepinephrine concentration from 394 +/- 141 to 207 +/- 73 pg X ml-1 (P less than 0.01). The plasma epinephrine concentration was reduced 49% after the induction of TEA.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1986

Effect of nicotine chewing gum on salivary secretion.

The effect of nicotine, placebo for nicotine or menthol-tasting chewing gums on salivation was studied in 25 healthy volunteers. The chewing of a commercial nicotine containing (2 mg) chewing gum (Nicorette) did not give a larger rate of salivation than did the chewing of a placebo chewing gum. For both types of chewing gums the rate of salivation was highest during the initial 5 min and it decreased thereafter. Menthol-tasting chewing gum gave a significantly higher amount of stimulated saliva. It is concluded that the addition of nicotine to a chewing gum does not provide an additional stimulus for salivation.

Adult↗
PubMed1985

24-hour cerebrospinal fluid levels of vasopressin in hydrocephalic patients.

The variation in vasopressin concentrations of ventricular cerebrospinal fluid and plasma throughout a 24-h period was studied in 10 patients with hydrocephalus. In 6 control patients, the diurnal variation in plasma vasopressin concentrations was studied. Vasopressin concentrations were determined by radioimmunoassay in plasma and in extracted and unextracted cerebrospinal fluid. Cortisol and osmolality in plasma were also measured. Vasopressin concentrations measured in extracted cerebrospinal fluid showed only small intra- and interindividual variation, while the corresponding values for unextracted cerebrospinal fluid were 2-5-fold higher and showed more variation. Plasma vasopressin concentrations varied considerably throughout the 24-h period in the individual hydrocephalic patient and between the patients. The pattern of variation was inconstant with no circadian rhythm, and the variation was not related to any changes in plasma osmolality, blood pressure or intracranial pressure. In some of the patients, the normal diurnal pattern of variation in plasma cortisol was broken, however, without a relation to the observed fluctuations in vasopressin concentrations. The abnormal variation of plasma vasopressin and cortisol was considered to reflect stress in connection with the intracranial pressure monitoring procedure. In the control patients, plasma vasopressin showed only small variations and plasma cortisol showed a normal diurnal rhythm. It is concluded that cerebrospinal fluid vasopressin concentration in patients with hydrocephalus is very constant throughout the day, even when plasma vasopressin concentrations show marked episodic increases. Thus, a circadian rhythm in the cerebrospinal fluid vasopressin concentration, as reported in several animal species, could not be confirmed in these patients.

Adult↗
PubMed1983

Synthesis of the porcine intestinal peptide PHI and its 24-glutamine analogue.

PHI--a new candidate hormone from porcine intestinal tract-- corresponds to a linear heptacosapeptide amide of remarkable sequence homology to the known members of the glucagon family, particularly to the vasoactive intestinal peptide (VIP) and secretin. The position 24 usually occupied by an aminodicarboxylic acid omega-amide, in the present case, however, carries a glutamic acid, thus opening the question of whether this structural feature is related to desamidation in one of the isolation and characterization steps or of whether it is significant for this peptide factor. Consequently the heptacosapeptide amides corresponding to the proposed primary structure and to its 24-glutamine analogue have been synthesized. Comparative chromatographic and biological studies on the natural and the two synthetic products have confirmed the correctness of the primary structure proposed for the isolated PHI. Since [24-glutamic acid] and [24-glutamine]PHI exhibit no significant differences in their biological potencies, the main question is still open of whether the position 24 in native PHI is occupied by the aminodicarboxylic acid omega-amide (glutamine) or by N-substituted derivatives (N-glycosyl).

Amino Acid Sequence↗
PubMed1982

Conservative treatment of uterine arteriovenous fistula.

A case of a uterine arteriovenous aneurysm in a 20-year-old woman is described. The patients's main symptom was copious uterine bleeding. The diagnostic difficulties are described and the importance of arteriography is emphasized. The aneurysm was occluded at laparotomy by introducing gel-foam into the uterine artery. The patient subsequently became pregnant and after an uneventful pregnancy was delivered of a healthy child. Thus, this type of conservative treatment seems to offer a possible means of avoiding hysterectomy in young patients with this rare condition who wish to retain their fertility.

Adult↗
PubMed1981

LCEC analysis of 5-hydroxytryptamine and norepinephrine in the human gastrointestinal tract.

The mucosal content of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) in different parts of the human gastrointestinal tract has been studied. Peroperative biopsies of normal mucosa were collected during various gastrointestinal operations. The amines were extracted and assayed by liquid chromatography with electrochemical detection (LCEC). The concentration of 5-HT was generally approximately 12 times higher than the NE concentration and the highest concentration for both amines was observed in the duodenum, 14 micrograms/g and 1.5 micrograms/g wet weight for 5-HT and NE respectively.

Chromatography, Liquid↗
PubMed1980

The peptidergic neural control of the feline pylorus.

By immunohistochemistry the three neuropeptides enkephalin, substance P, and VIP were all localized to numerous nerve fibers in the smooth muscle layer and the myenteric plexus of the feline pylorus. The motor activity of the pylorus was studied by recording changes in the volume flow of body-warm saline through the sphincter at constant perfusion pressure in anesthetized cats. Efferent electric stimulation of the cervical vagi (8 V; 5 ms; 8 Hz) elicited a noncholinergic, nonadrenergic pyloric contraction, which was blocked by infusion of the opiate receptor antagonist naloxone. The peptides were injected into a regional gastric artery to the pylorus antrum. Enkephalin and substance P in micronanomolar doses resulted in a prompt contraction of 3 - 5 min duration. Equimolar doses of naloxone blocked the enkephalin-induced contraction, and atropine blocked the SP contraction. On the other hand, VIP caused a prompt dilatation, which could not be blocked in this study. Altogether the findings suggest a peptidergic motor control of the feline pylorus using several transmission mechanisms.

Animals↗
PubMed1980

One thousand consecutive midtrimester amniocenteses.

One thousand women underwent amniocentesis as part of a prenatal investigation and were observed throughout gestation and delivery. Amniocenteses and chromosome determinations were performed at a center with great experience in these techniques. Under these conditions, the risks attached to amniocentesis are minimal, and the chromosome determinations are reliable. In this study, 21 women chose to terminate their pregnancy because the fetus was expected to have a serious abnormality. In all the cases in which the diagnosis could be investigated after legal termination, the cytogenetic diagnosis proved correct.

Amniocentesis↗
PubMed1980

Kidney size in normal children measured by sonography.

Kidney length and depth were measured by sonography in 46 normal children fro 0 to 16 years of age. Sonography was used to obtain kidney measurements without the known magnification caused by factors of chemical and photographic nature seen by urography. The results of our study were used to control the age-adapted equipment for renography in children. There was a good correlation between kidney length and depth and variables like age, weight, height and body surface area. The best values were found in the correlations to body surface area. We could confirm the previous findings by other methods of kidney size measurements in children that there is no significant difference in kidney length between boys and girls. The left kidney is slightly longer than the right one and the kidney centre distance is slightly but significantly larger on the left side. No such difference was present in the distance skin to kidney surface.

Adolescent↗
PubMed1980

Evidence for vagal enkephalinergic neural control of the feline pylorus and stomach.

The atropine- and guanethidine-resistant contraction of the cat pyloric sphincter induced by efferent stimulation of the cervical vagi, was studied with a new method for measuring transpyloric flow. The pyloric contraction was blocked in a dose-dependent manner by the opiate antagonist naloxone infused intraarterially to the pyloric region. Local intraarterial injection of morphine or enkephalinamide elicited a pyloric and gastric contraction. Leu- and met-enkephalin intraarterially elicited a pyloric contraction and a gastric relaxation. These effects could be prevented or reversed by naloxone. Immunohistochemical studies revealed a particularly rich enkephalinergic innervation of the pylorus with dense networks of varicose nerve fibers with enkephalin-like immunoreactivity both in the circular smooth muscle layer and in the myenteric plexus. Furthermore, many cell bodies of the myenteric plexus with enkephalin-like material were demonstrated. The corpus-antrum was sparsely innervated by enkephalin-like nerves to the circular muscle layer and only few immunoreactive cell bodies were observed in the myenteric plexus. These results together suggest a vagal control of the feline pylorus and stomach mediated via enkephalinergic neurons.

Animals↗
PubMed1976

Postnatal ontogenic development of the adrenergic innervation pattern in the rat portal vein. A histochemical study.

The postnatal development of the adrenergic innervation pattern in the rat portal vein has been studied with the histochemical fluorescence method of Hillarp and Falck. Stretch preparations and transverse freeze-dried sections of intact portal veins were studied from rats during the first 5 weeks of life and from adult rats. Orientation of undifferentiated smooth muscle cells into two layers was observed at 4 days of age. Dominance of the thick outer longitudinal muscle layer was apparent at two weeks of age. A terminal adrenergic nerve plexus with some varicosities was restricted outside the media at the end of the first week. Ingrowth of penetrating non-terminal adrenergic nerve fibers through the longitudinal muscle layer occurred during the second week of age when the main terminal nerve plexus was developing between the two muscle layers. After 3 weeks of age the adult pattern of a two-dimensional adrenergic plexus between the muscle was established. In the adult rat pharmacological treatment with nialamide and noradrenaline revealed the thin, penetrating non-terminal adrenergic nerve fibers in the longitudinal muscle layer which were poorly visible otherwise. The present observations strongly indicate that the main adrenergic plexus between the two muscle layers emanates directly from the outer axonal plexus. These findings are discussed regarding possible trophic interactions between ingrowing sympathetic adrenergic vasomotor nerves and maturing vascular smooth muscle.

Animals↗