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Biomedical subjects

B Lindblom

Publications and source records attributed to B Lindblom.

At least 181 records · Page 10Linked to original sources
PubMed1983

Allo-immune anti-Iak sera of individual mice detect HLA-DR-associated polymorphism on human B cells.

A murine allo-immune A.TH anti-A.TL (anti-Iak) serum pool and sera from individual immunized mice were tested on a large panel of human DR typed B cells, obtained from peripheral blood (PBL-B cells), and human lymphoid tumour cells. The anti-Iak serum pool appeared to be a useful reagent both in cytotoxicity and immunofluorescence for the examination of the presence of class-2 HLA molecules on tumour cells. Only one discrepancy was observed when the pool was tested in parallel with a xeno-anti-human B-cell serum on the cells of 56 lymphoid tumours. Nine sera from individual mice were tested on a panel of 93 PBL-B cells. Some of these sera reacted significantly more weakly with human B cells positive for the DR5 and/or DR7 antigens.

Animals↗
PubMed1983

Survival time among patients with glaucomatous visual field defects.

During our studies on glaucoma we have made an important and surprising observation. We think it is urgent to report that we have found the survival time of glaucoma patients seems to be substantially shortened. To the best of our knowledge this has not been previously reported.

Aged↗
PubMed1983

Interaction between PGs and catecholamines on cervical collagen synthesis.

Specimens from the upper part of the cervix were excised and chopped into 1 mm thick slices. These were incubated in buffer containing [3H] proline fortified with PGE2 and/or NA and the incorporation into total protein was measured after various incubation periods. In certain experiments the slices were preincubated with reserpine to deplete the tissue stores of catecholamines. Both PGE2 and NA were able to influence the incorporation of [3H] proline in such a way that the stimulatory effect of PGE2 was counteracted by reserpine in the luteal phase of the cycle, while NA-stimulated incorporation of [3H] proline was inhibited by PGE2 in the late follicular phase. Both clinical and experimental studies have shown that PGs per se interfere with the biophysical and biochemical properties of the cervix. The present results indicate that there also exists an interaction between PGs and catecholamines.

Cervix Uteri↗
PubMed1983

Impaired conA suppressor cell activity in patients with rheumatoid arthritis shows normalization during fasting.

Normal controls and patients with rheumatoid arthritis (RA) were investigated with respect to quantitative lymphocyte proliferation (LP) after concanavalin-A (conA) activation and to conA-induced suppressor cell activity (conA-SC). Measurements and assessment of RA activity were made at the beginning and end of a 10-day fast. The controls showed depressed (p less than 0.05) LP at the end of the fast, but no change in conA-SC activity. The RA group showed subnormal (p less than 0.05) LP and conA-SC (p less than 0.01) at the beginning of the experiment. After fasting they showed clinical improvement, the LP was not further depressed, and the initially low conA-SC had become normal.

Adult↗
PubMed1983

PGI2 may play a role in the pathophysiology of dysmenorrhea.

Small longitudinally or helically cut strips from the ascending branch of the uterine artery were mounted in organ chambers for isometric recording of contractile activity. PGI2(3-300 ng/ml) caused a concentration-dependent relaxation of spontaneously active preparations, whereas no inhibitory effect could be observed on non-active strips. Furthermore, the compound counteracted the stimulatory effects of PGE2, PGF2 alpha, and NA, but not that of transmural nerve stimulation. The effect of PGI2 could be of interest in that the compound may balance the action of vasoconstricting agents. A disturbance of this balance may be a hitherto unrecognized contributing pathophysiological mechanism in the development of dysmenorrhea.

Arteries↗
PubMed1983

Prostaglandins and oviductal function.

This review presents evidence of a specific involvement of PGs in the function of the human Fallopian tube. A role of PGE and PGF in ovum transport seems plausible, but data from human studies are still fragmentary. High estrogen levels in tissue at ovulation may cause 'tubal lock' by increasing the activity of the isthmic musculature. This effect might be exerted by an estrogen-dependent increase in the formation of PGF as well as by increased sensitivity to PGF. The elevation of progesterone levels in the early luteal phase would counteract the effect of estrogens by instead favoring E prostaglandins. PGE seems to relax the isthmic muscle, allowing the entry of the fertilized ovum into the uterine cavity.

Alprostadil↗
PubMed1982

Simultaneous recording of electrical and mechanical activity in isolated smooth muscle of the human oviduct.

Small strips from the circular muscle layer at the ampullary-isthmic junction of the human oviduct were suspended in an organ bath. Mechanical activity was recorded isometrically by a force displacement transducer and electrical activity was registered simultaneously by an extracellular glass-silver electrode. Spontaneous contractions were not associated with "burst" of action potentials but were preceded by a single spike with a duration of approximately 700 milliseconds. During the rest of the contraction there was a total absence of potential changes. Prostaglandin E2 (PGE2) abolished spike discharge leading to inhibition of mechanical activity. Prostaglandin F 2 alpha (PGF 2 alpha), on the other hand, increased the rate of action potentials and, hence, the frequency of contraction. However, neither PGE2 nor PGF2 alpha changed the configuration of the spike. It is concluded that in smooth muscle of the human oviduct, there is a high degree of agreement between the electrical and mechanical signals and that prostaglandins act by reducing or increasing the rate of spike discharge but not by influencing the character of the action potential.

Action Potentials↗
PubMed1982

Prevalence of visual field defects due to capsular and simple glaucoma in Hälsingland, Sweden.

In a region where both simple and capsular glaucoma are common, the observed prevalence of glaucoma with glaucomatous visual field defects based on hospital records is presented. The prevalence increased with increasing age to a maximum of 4.5% of the age group 81-85. Capsular glaucomas accounted for two thirds of the glaucomatous visual field defects. A comparison with previous population surveys indicates that the frequency of simple glaucoma is of the same magnitude as elsewhere. The high frequency of glaucomatous visual field defects can be due to the occurrence of capsular glaucoma. This supports the hypothesis that capsular glaucoma has its own epidemiology.

Adolescent↗
PubMed1982

Oxytocin, prostaglandins, and contractility of the human uterus at term pregnancy.

The contractile properties of myometrial "mini-strips" from the upper and lower uterine segments were studied by a superfusion technique. These samples of myometrium were taken from women delivered by elective cesarean section in the 39th week of pregnancy. The frequency of spontaneous contractions was significantly higher in isthmic myometrial specimens than in corpus specimens, whereas amplitude and duration of contractions did not differ. Both isthmic and corpus myometrium were stimulated by prostaglandin E2 at low concentrations and inhibited at high concentrations. PGF2 alpha induced an excitory response in the isthmic strips but surprisingly not in preparations from the corpus. However, PGF2 alpha restored normal spontaneous activity following inhibition of the contractility with indomethacin. Oxytocin caused an excitory response over a wide concentration range in both types of specimen and this response was not reduced by pretreatment with indomethacin. These findings suggest that endogenous prostaglandin synthesis is a necessary prerequisite for spontaneous myometrial activity at term pregnancy and that prostaglandins are not essential for the excitatory effect of oxytocin.

Adult↗
PubMed1981

Copper and contractility of the human fallopian tube.

Muscle specimens were obtained from human oviducts during legal surgical sterilizations. Muscle strips (1 mm wide) were dissected from the circular and longitudinal muscle layers at the ampullary-isthmic junction, and contractile activity was recorded during short-term experiments in an organ bath. Administration of copper chloride induced a clear-cut excitatory response in both muscle layers. The response was, in many respects, similar to that evoked by low concentrations of prostaglandin F2 alpha (PGF2 alpha) but differed from the response induced by PGE2. Pretreatment of the tissue with indomethacin blocked the excitatory action of copper and frequently reversed the response into an inhibition of the contractile activity. After maximal stimulation of contractility by exogenous PGF2 alpha, copper was ineffective as a stimulant, whereas a maximal response elicited by copper could be further augmented by the addition of PGF2 alpha. The conclusion is that copper ions released from a copper intrauterine contraceptive device may increase contractility of the oviducts by an action on endogeneous synthesis of prostaglandins, predominantly of the F series. In addition, copper also seems to possess an inhibitory influence on motility of the oviducts, which becomes apparent only when the excitatory effect is blocked pharmacologically.

Adult↗
PubMed1981

Effects of prostaglandins on the isolated uterine artery of nonpregnant women.

Specimens from the ascending branch of the human uterine artery were obtained from 35 nonpregnant fertile women undergoing hysterectomy. The specimens were cut either longitudinally or helically and mounted in organ chambers for isometric recording of the contractile activity. Spontaneous phasic activity occurred in 30% of the specimens. Both PGE2 and PGF2 alpha caused an increase in basal tonus of the strips while PGI2 relaxed spontaneously active as well as PG- and norepinephrine (NE2)-stimulated preparations. PGI2 had no effect on nonactive specimens, NE and transmural nerve stimulation (TNS) induced contractile activity that could be blocked by phenoxybenzamine. PGI2 counteracted the NE-induced response but not that of TNS. It is concluded that PGI2, which is synthesized both within the vessel wall and the myometrium, has a potent relaxing effect on uterine arteries and that the compound may balance the effect of vasocontricting substances.

Adult↗
PubMed1981

Production of bite-block vowels: acoustic equivalence by selective compensation.

Acoustic and articulatory data are reported for steady state vowels produced both normally and with a bite block. The formant patterns of the bite-block vowels were found to approximate those of the naturally spoken vowels. Measurements derived from lateral view still x-ray films showed that the bite blocks induce drastic articulatory reorganization. Using a mandibular frame of reference, we found that speakers compensated for a large bite block by using supershapes of the tongue and the lips (for [u] and [o]). Comparing the two productions using a maxillary frame of reference, we noted that compensation was maximum at the points of maximum constriction and incomplete or partial at points where the vocal-tract area was large. A computer simulation of our speakers' compensatory strategy revealed that they behaved optimally according to acoustic theory. These findings suggest that a vowel target is coded neurophysiologically in terms of acoustically significant area-function, specifically, by information related to cavity configuration at points of maximum constriction.

Adult↗
PubMed1981

Modeling the judgment of vowel quality differences.

The hypothesis of this study is that the auditory cues relevant to listeners' judgment of vowel quality are a spectral representation of loudness density versus pitch. A model is described that generates such patterns for steady-state vowels. In addition to the nonlinear transformations underlying the loudness density and pitch scales, it incorporates experimentally established characteristics associated with frequency resolution and masking, such as the critical band concept. This model is combined with a measure of auditory perceptual distance which, operating on pairs of vowels, treats each stimulus representation as a single spectral shape. In order to test the distance metric and the model, experimental data were gathered from listeners' numerical estimates of quality differences between stimulus pairs which compared four-formant and two-formant vowels. The correlation between experimental and theoretical results was 0.89. We interpret this value to indicate that the present definition of auditory cue and auditory distance can be said to account for the experimental behavior of our listeners only in a rather gross fashion. On the other hand, the theory was developed on the basis of rather conservative assumptions about the nature of auditory cues. For instance, the model ignores the possibility of temporal coding and certain nonlinear effects, and it does not pay special attention to spectral peaks. Seen in that light, the agreement between observed and predicted auditory distance is remarkably good.

Auditory Perception↗
PubMed1980

Adrenergic responses of the various smooth muscle layers at the human uterotubal junction.

The different muscle layers at the human uterotubal junction (UTJ) were mechanically separated, and 1-mm wide muscle strips were isolated and mounted in organ chambers for isometric recording of contractile activity. It was found that the adrenergic neurotransmitter noradrenalin elicited an inhibition of the spontaneous phasic activity in the inner longitudinal and the intermediate circular layers but caused a clear-cut excitatory response in the outer, spiral-shaped (uterine) layer. The excitatory response was totally blocked by treatment with phenoxybenzamine, an alpha-adrenoceptor antagonist, whereas the inhibitory effects were abolished after pretreatment with the beta-adrenoceptor antagonist propranolol. The data demonstrate a differentiated distribution of alpha- and beta-adrenoceptors in the smooth musculature at the proximal end of the tubal isthmus. It is suggested that this arrangement might serve an important purpose in the physiologic control of ovum transport in women.

Edetic Acid↗
PubMed1980

Contractile patterns of isolated oviductal smooth muscle under different hormonal conditions.

The isthmic portion of the human fallopian tube was excised during surgery and the ampullary-isthmic junction was identified. Muscle strips (1-mm wide) were dissected from the outer longitudinal and the inner circular layers at this region and used for isometric recordings of spontaneous contractile activity in organ bath experiments. It was found that the amplitude and the duration of individual contractions were similar during various phases of normal menstrual cycles, whereas the frequency of contractions was significantly increased during the periovulatory period in both circular and longitudinal muscle. During early pregnancy or treatment with combined oral contraceptives the motility pattern was similar to that observed in the late luteal phase, being characterized by a comparatively low contraction frequency. In the perimenopausal period, irregular patterns were frequently observed whereas preparations obtained from postmenopausal women exhibited a very weak activity with low amplitude and frequency of contractions. Similar activity was encountered in specimens from patients treated with androgens. It is concluded that endogenous estrogens stimulate human oviductal contractility while endogenous progesterone has a depressive action on tubal activity. Both effects occur with a certain delay and are prolonged for up to 3 days, i.e., the changes in the serum levels of ovarian steroids and the induced alterations of tubal contractility are out of phase.

Adult↗