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Biomedical subjects

B Lindblom

Publications and source records attributed to B Lindblom.

At least 163 records · Page 9Linked to original sources
PubMed1985

The role of prostaglandins for the coordination of myometrial forces during labour.

Systematic studies using a superfusion technique for recording myometrial contractility in vitro have been conducted in our department to explore whether prostaglandins (PG) have a differential action on the different segments of the pregnant uterus and also whether the qualitative and quantitative response undergoes a change during spontaneous labour. Myometrial specimens were excised from the fundal area and from the lower uterine segment at elective caesarean section in the 39th week of pregnancy before commencement of labour and at acute caesarean section during ongoing labour. Before labour PGF2 alpha was without or had a very weak effect on upper segment preparations but was stimulatory on lower segment specimens. PGE2 and PGI2 generally induced a biphasic dose-dependent response (stimulation followed by inhibition). During spontaneous labour PGF2 alpha and PGE2 always stimulated upper segment preparations while the contractile activity of specimens from the lower segment was inhibited by PGE2, PGF2 alpha was generally without effect. PGI2 had the same biphasic action before as during labour. With all reservations for the validity of in vitro experiments, the results favour the hypothesis that initiation of labour in the human involves a qualitative shift in the myometrial reactivity to prostaglandins. These alterations may involve suppression of expulsive forces and perhaps some tightening of the lower uterine segment during pregnancy. Following initiation of labour there is a marked increase in the excitatory action of both PGE2 and PGF2 alpha in the fundal area while the lower uterine segment reacts in a way that favours dilatation.

Dinoprost↗
PubMed1985

Has cervical smooth muscle any physiological role in the human?

Strips of human cervical tissue were obtained by needle biopsy and contractile activity was registered isometrically in a tissue chamber perfused by Krebs-Ringer bicarbonate buffer. The most frequently encountered pattern of contractile activity was high frequency-short duration. Prostaglandin (PG)E2, PGI2 and 6-keto-PGF1 alpha had an inhibitory effect on the muscular activity. Cervical muscle from pregnant women was more sensitive to PGE2 than specimens from non-pregnant women. PGF2 alpha had no apparent effect on cervical contractility in non-pregnant and early pregnant patients. In late pregnancy, however, PGF2 alpha inhibited muscle contractions. The present results point to a physiological role of the cervical muscles for the control of cervical competence during pregnancy. The inhibitory effect of PGs on the muscle activity may promote cervical dilatation and retraction.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Catecholamines and contractility of the human myometrium at term: a possible role for prostaglandins.

The contractile response of small myometrial specimens from the term pregnant human uterus was investigated using a superfusion technique. Adrenaline, noradrenaline and dopamine all had a stimulatory effect on the contractility. It was also demonstrated that this stimulatory effect was alpha-adrenoceptor mediated. If the tissue was pretreated with the prostaglandin synthetase inhibitor indomethacin or the arachidonic acid analogue eicosa-5,8,11,14-tetraenoic acid the effect of catecholamines was significantly reduced. This suggests a specific role of prostaglandins in the mechanism of action of catecholamines on the human myometrium.

Arachidonic Acids↗
PubMed1984

Difference between young and old patients in characteristics of leukemic cells: older patients have cells growing excessively in vitro, with low antigenicity despite high HLA-DR antigens.

Fifty-six patients with acute, non-lymphatic leukemia in the initial phase were studied. The poor prognostic signs were excessive in vitro growth, many HLA-DR-positive cells, or a low ratio of leukemic cell antigenicity to HLA-DR positivity and age. The cells from older patients formed more clusters (P less than 0.05), and they had less capacity to stimulate normal allogeneic lymphocytes (P less than 0.05) than those from younger patients. Cells forming many clusters also were more often (P less than 0.01) HLA-DR-positive than those forming few clusters. It is suggested that the prognosis in old patients with acute leukemia is poor in part because their leukemic cells have characteristics different from those of young patients.

Adolescent↗
PubMed1984

Observed incidence of glaucoma in Hälsingland, Sweden.

In a well defined population, the observed incidence of different types of glaucoma during the years 1980-82 is presented. The great majority of glaucoma patients was found to have primary open angle glaucoma, and of these approximately 3/4 had capsular glaucoma. The observed annual incidence of all types of glaucoma increases with increasing age to a maximum of 0.7% in the age group 81-85 years. In the same age group, the annual incidence of primary open angle glaucoma with visual field defects was 0.44%.

Age Factors↗
PubMed1984

Functional damage at diagnosis of primary open angle glaucoma.

In a well defined population, all patients with newly diagnosed primary open angle glaucoma were classified according to the degree of functional damage at diagnosis. A comparison was made between patients with simple and capsular glaucoma. No difference could be found between the 2 types of glaucoma when the severity of visual damage at diagnosis was compared. Eyes with capsular glaucoma were found to have significantly higher intraocular pressure than eyes with simple glaucoma in corresponding glaucoma stage. No obvious correlation between age and functional damage at diagnosis was found.

Age Factors↗
PubMed1984

Functional precursors to language and its lateralization.

An adequate account of language evolution must reconcile the propositions that language is unique but has precursors. The paper of Bellman and Goldberg and that of Tzeng and Wang each neglects one of these propositions. We suggest that the uniqueness of language lies primarily in its dualistic structure which has a frame-content mode of organization: at the phonological level, consonant and vowel elements are inserted into syllabic frames; and at the morphological level, stem forms of content words are inserted into syntactic frames. We suggest that the morphological level evolved from the phonological level and that the frame-content mode of organization in phonology had a precursor in the form of bimanual coordination in which the nonpreferred (frame) hand holds an object operated on by the preferred hand (content). It is argued that lateralization of cortical function evolved first for bimanual coordination, then for language. Old World monkey hand preferences may be consistent with both the putative left-hemisphere specialization for bimanual coordination and the human right-hemisphere specialization for spatial functions.

Brain↗
PubMed1984

Myometrial response to prostaglandins during labor.

The myometrial response to prostaglandins (PGs) before labor has been studied earlier in this laboratory by the use of a superfusion technique. In the present investigation the same technique was used to explore the contractile effect of PGE2 and PGF2 alpha on myometrial strips obtained during active, spontaneous labor. Both PGE2 and PGF2 alpha had a marked stimulatory effect on strips from the upper uterine segment. The lower segment reacted to PGE2 by inhibition but not at all or slightly stimulatory to PGF2 alpha. Oxytocin constantly induced an excitatory response in both segments. The results support the concept of a prostaglandin-mediated 'fundal dominance' during labor and indicate that PGs contribute to a relaxation of the lower uterine segment. Taken together with previously obtained data the present results provide evidence for a critical change in myometrial responsiveness to prostaglandins by the time of parturition.

Dinoprost↗
PubMed1984

Human lymphocyte antigen DR types in relation to early clinical manifestations in diabetic children.

Human lymphocyte antigen (HLA)-DR-typing was performed in 117 insulin-dependent diabetics with age at onset between 0.5 and 17 years (mean +/- SD, 9.0 +/- 3.9); 115 of 117 patients were DR3- and/or DR4-positive. DR4 was very common, seen alone or in combination with other DR types in 82.9% of the patients. Only two children were DR2-positive, but they also were DR4-positive. A comparison between DR3 and DR4 patients showed that DR4 patients manifested a seasonal variation of onset (most common onset during spring and autumn), had more severe signs and symptoms of the disease at onset, and were less likely to have a partial remission than patients with DR3. The results support the hypothesis that insulin-dependent diabetes mellitus is a genetically heterogeneous disease.

Adolescent↗
PubMed1984

Inhibitory action of relaxin on human cervical smooth muscle.

The influence of purified porcine relaxin on contractility of human cervical smooth muscle was investigated in vitro. Strips of cervical tissue were obtained by needle biopsy from pregnant and nonpregnant women and were mounted in a superfused organ chamber for isometric measurement of contractile activity. Relaxin (0.005-25 micrograms/ml) inhibited the spontaneous contractions in cervical strips from 18% of nonpregnant, 68% of early pregnant, and in 100% of term pregnant women. These results indicate that relaxin has an inhibitory action on cervical smooth muscle and that this effect is more constantly detected as pregnancy proceeds.

Animals↗
PubMed1984

Adrenoceptor mechanisms in the regulation of contractile activity in the human cervix.

The effects of adrenoceptor agonists and antagonists on the contractile activity of cervical strips from early pregnant and nonpregnant women were studied. Noradrenaline and the alpha-adrenoceptor agonist, phenylephrine, had a stimulatory effect on smooth muscle activity. This response could be blocked totally by the alpha-adrenoceptor antagonist, phenoxybenzamine. Isoprenaline, known to be a beta-adrenoceptor agonist with some alpha-adrenoceptor activity, had stimulatory and inhibitory effects, whereas the beta 2-adrenoceptor agonist, terbutaline, exhibited a pure inhibitory action. The inhibitory effects of isoprenaline and terbutaline were totally blocked by the beta-adrenoceptor antagonist propranolol. In pregnant patients, the sensitivity to noradrenaline was significantly higher, and the inhibitory action of terbutaline was less pronounced, which indicated the predominance of alpha-receptor activity in the uterine cervix during pregnancy.

Adolescent↗
PubMed1984

Structural and functional evidence for the denervation of human myometrium during pregnancy.

The neuronal influence of the contractility of the term-pregnant human uterus was studied by pharmacologic and histochemical methods. By the use of adrenergic and cholinergic antagonists or tetrodotoxin it was demonstrated that the contractile response of superfused myometrial strips from the term-pregnant uterus to electrofield stimulation was not influenced by any neuronal factor. Using an indirect immunofluorescence technique with an antiserum to the glial and Schwann cell specific S-100 protein, a marked paucity of nerve fibers was demonstrated in myometrial strips from the term-pregnant uterus as compared with the nonpregnant uterus. It is concluded that the described decrease of nerve fibers within the myometrium of the pregnant uterus may be of importance for the myometrial activity during pregnancy and parturition.

Adult↗
PubMed1984

Influence of prostaglandins on contractility of the isolated human cervical muscle.

The contractile activity of smooth muscle from the pregnant and nonpregnant human cervix uteri was studied in organ bath experiments. Several patterns of spontaneous activity with varying frequency and amplitude were observed. Prostaglandin E2 inhibited muscle activity in a concentration-dependent manner, and total inhibition was achieved in pregnant tissue at extremely low concentrations. Prostaglandin F2 alpha, on the other hand, did not influence spontaneous contractions. Prostaglandin I2 and 6-keto-prostaglandin F1 alpha had an inhibitory effect but only at comparatively high concentrations. 5,8,11,14-Eicosatetraynoic acid and indomethacin abolished spontaneous contractions, indicating a regulatory influence of endogenous prostanoids on cervical contractility. The extreme sensitivity to prostaglandin E2 and enhancement of its action during early pregnancy provide evidence for a specific role of this compound in controlling cervical smooth muscle activity in the human female.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

The role of prostaglandins in the stimulatory action of catecholamines on myometrial activity in term pregnant women.

The response of small strips of human myometrium to catecholamines was investigated using a superfusion technique. In term pregnant uteri, adrenaline (A) and noradrenaline (NA) caused contraction of both the upper and lower segments, but there was no significant change in response depending on whether or not the patient was in labor. Phenoxybenzamine blocked the excitatory effect of both A and NA, suggesting an alpha-adrenoceptor-mediated effect. Propranolol did not enhance the effect of A or NA, indicating that stimulation of beta-adrenoceptors does not contribute to the effect on the pregnant human uterus. Pretreatment of the tissue with indomethacin or eicosa-5,8,11,14-tetraynoic acid (ETA), drugs known to block endogenous prostaglandin synthesis, markedly reduced the effects of both A and NA. This suggests a specific role of prostaglandins in the mechanism of action of catecholamines on the human myometrium.

Adrenergic Agonists↗
PubMed1983

The effect of prostaglandin I on the contractility of the term pregnant human myometrium.

Small myometrial strips were dissected from the upper and lower segments of the term pregnant human uterus. The specimens were superfused in organ chambers and contractile activity was recorded isometrically. In strips from the upper segment, prostacyclin (PGI2), induced an initial excitatory response followed in the majority of experiments by transient inhibition. In the lower segment the response was generally the same although direct inhibition without initial stimulation occurred in some cases. During the period of inhibition the specimens were refractory to iterated exposure to PGI2. Furthermore, during this period of PGI2-induced inhibition the muscle strip was also refractory to PGE2 but responded to PGF2 alpha and oxytocin by stimulation. After inhibition of spontaneous contractile activity induced by indomethacin PGI2 induced an excitatory response. The results do not indicate any critical change in the myometrial responsiveness of the upper uterine segment to PGI2 during labor. In strips from the lower segment obtained before labor there tended to be a dominance of non-responders and inhibition only as compared to the results during labor. Nevertheless, whether or not PGI2 under physiological or pharmacological conditions has any significant influence on the contractility of the term pregnant human uterus, still remains obscure. As judged from earlier reports from our laboratory and the present study it is evident that the uterine vessels are considerably more sensitive to the action of PGI2 than the myometrium.

Dinoprost↗
PubMed1983

Effects of intraluminal administration of adrenoceptor agonists on transisthmic flow in the rabbit oviduct.

By perfusing the isthmic segment of the rabbit oviduct in vivo at low hydrostatic pressures with Ringer's solution (+38 degrees C), the resistance of the isthmic segment could be measured quantitatively using a drop-recording system. Transisthmic flow, from mid-tube to the uterine end, was thus studied in 45 animals, 48 h after human chorionic gonadotropin (hCG) injection. Stimulation of alpha-adrenoceptors by administration of norepinephrine or phenylephrine to the perfusate resulted in an immediate reduction or cessation of the basal flow. The duration of this effect varied dose-dependently. The administration of beta-adrenoceptor agonists (isoprenaline, prenalterol or terbutaline) markedly increased transisthmic flow. The beta 2-adrenoceptor agonist terbutaline was considerably more potent than the other beta-agonists. Thus, it seems that the isthmic contraction caused by adrenergic luminal stimulation is mediated via alpha-adrenoceptors, while the isthmic dilation is mediated via beta-adrenoceptors, mainly of the beta 2-type.

Animals↗