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Biomedical subjects

S Thrower

Publications and source records attributed to S Thrower.

At least 19 recordsLinked to original sources
PubMed1991

Further studies of lectin binding by villous and extravillous trophoblast in normal and pathological pregnancy.

Examination of human pregnancy tissues with a panel of lectins provides the opportunity to probe different aspects of carbohydrate structure. Nine biotinylated lectins [concanavalin A (con A), wheat germ agglutin (WGA), Lens culinaris A (LCH-A), Pisum sativum (PSA), Phaseolus vulgaris (PHA-E and PHA-L), Ulex europaeus 1 (UEA1), Griffonia simplicifolia (GSI and GSII)] were used to investigate the lectin binding of human trophoblast in normal, tubal, and molar pregnancy. All lectins except UEA1 bound to normal villous syncytiotrophoblast. Binding of lectins to extravillous trophoblast was more restricted than to villous trophoblast, occurring predominantly with con A, PHA-E, PHA-L, WGA, GSI, and GSII. LCH-A reacted with cyto-trophoblastic columns but not with interstitial or endovascular trophoblast. Con A and GSII were the only lectins that bound to trophoblastic giant cells. GSI and GSII bound preferentially to extravillous trophoblast, showing only focal reactivity with villous trophoblast. Lectin binding in ectopic pregnancy was similar to that in normal first-trimester intrauterine pregnancy. Reactivity in molar pregnancy also generally mirrored that observed in normal pregnancy; however, reactivity of GSII with villous trophoblast was more consistent than that observed in normal pregnancy, and GSI showed uniform binding to proliferating syncytial areas. Thus, lectin binding studies allow definition of surface carbohydrates, which may play a role in the controlled trophoblast proliferation and invasion that occurs in normal pregnancy.

Amnion↗
PubMed1988

Asymptomatic peptic disease in patients undergoing major elective operations: a prospective endoscopic study.

Postoperative bleeding is usually attributed to stress ulcers; however, occult preoperative lesions could also be responsible. To determine their frequency and nature, we prospectively examined 72 patients endoscopically prior to major elective operations. Entry criteria included a planned stay in the Surgical Intensive Care Unit, greater than 2 days, and a negative history, physical examination, and stool guaiac. Gastric and duodenal mucosae were scored separately, using a 0- to 7-point scale. Scores were graded negative (0), hyperemia (1), gastroduodenitis (2-5), mucosal erosions (6), and ulcers (7). Erosions or ulcers were found in 14% of patients and gastroduodenitis is an additional 10%. We found that none of the 27 risk factors or any combination of factors tested correlated with ulcers, erosions, or gastroduodenitis. Thus, patients with asymptomatic gastroduodenal erosions or ulcerations could not be identified preoperatively, except by endoscopy. Until the significance of these lesions as cause of postoperative bleeding is determined, we recommend routine postoperative gastric pH titration with antacids for patients undergoing major elective operations.

Gastrointestinal Hemorrhage↗
PubMed1987

Single session treatment for bleeding hemorrhoids.

Fifty consecutive outpatients with bleeding internal hemorrhoids were prospectively treated with a single application of rubber band ligation or infrared coagulation. Complete follow-up observation was obtained in 48 patients (23 underwent rubber band ligation and 25 underwent infrared coagulation). At one month after treatment, 22 patients who underwent rubber band ligation and 16 who underwent infrared coagulation, were symptomatically improved (p less than 0.05). At six months, 15 patients who had undergone rubber band ligation and ten who had infrared coagulation treatment, remained improved (p less than 0.05). There was no statistical difference in the discomfort experienced by either group during or after the procedure as determined by a self-assessment scale. Two patients who underwent rubber band ligation experienced complications--a thrombosed external hemorrhoid developed in one patient and another had delayed rectal bleeding. Although associated with occasional complications after treatment, rubber band ligation is more effective than in infrared coagulation for single session treatment of bleeding internal hemorrhoids.

Ambulatory Surgical Procedures↗
PubMed1981

The nuclear oestrogen receptor in the female rat. Effects of oestradiol administration during the oestrous cycle on the uterus and contrasting effects of progesterone on the uterus and hypothalamus.

Oestradiol administration to immature or ovariectomized rats has been reported to increase the uterine content of long-term nuclear oestrogen receptors. However, in the intact adult female rat, oestradiol administration did not increase the concentration of long-term nuclear oestrogen receptors at all phases of the oestrous cycle. Progesterone administration to rats in late dioestrus did not affect the concentration of uterine nuclear oestrogen receptors 24 h later, although it did prevent the normal cyclic increase at pro-oestrus in the concentration of hypothalamic nuclear oestrogen receptors. Our results therefore show that in the intact adult rat, factors other than the concentration of progesterone or oestradiol determine the nuclear concentration of oestrogen receptors in the uterus. They also demonstrate differences between neural and non-neural tissues in the regulation of oestrogen-receptor interactions.

Animals↗
PubMed1981

The unoccupied nuclear oestradiol receptor in the rat uterus and hypothalamus during the oestrous cycle.

The nuclear oestrogen receptor population in the rat uterus contained an unoccupied receptor component that bound oestradiol with the high affinity (Kd congruent to 0.5 nM) characteristic of oestrogen receptors. This unoccupied receptor was present at all phases of the oestrous cycle. Its content changed in parallel with that of the total nuclear receptor during the cycle. Oestradiol administration to the immature rat resulted in increases in the uterine content of long-term nuclear receptors (i.e., those still present 8 h after administration); these increases were due to occupied oestrogen receptors, since the content of unoccupied receptor was unchanged. Our previous experiments [White & Lim (1980) Biochem. J. 190, 833-837] have shown in contrast, that oestradiol administration results in an increase in the content of unoccupied nuclear receptor in the hypothalamus. However, as in the uterus, similar cyclic changes in the content of unoccupied nuclear receptor occurred in parallel with those of the total nuclear receptor population in the hypothalamus. Differences and similarities between the unoccupied nuclear receptor of the uterus and hypothalamus are briefly discussed.

Animals↗
PubMed1980

A comparison of the relationships between progestin receptors and oestrogen receptors in neural and non-neural target tissues of the rat during the oestrous cycle.

Similar cyclic changes in the content of nuclear oestrogen receptor occurred in the hypothalamus, cerebral cortex, uterus and pituitary during the oestrous cycle. The relationship of the unoccupied to the total nuclear oestrogen receptor at each phase was similar in all these tissues. However, cyclic changes in the content of the cytosol progestin receptor occurred only in the uterus and pituitary (where they paralleled changes in the nuclear oestrogen receptor), but not in the hypothalamus or cerebral cortex.

Animals↗
PubMed1980

Characterization of rat hypothalamic progestin binding by spheroidal hydroxylapatite chromatography.

The progestin-high-affinity-binding components in rat target tissues have been assayed by a simple and precise procedure by using spheroidal hydroxylapatite. The progestin 'receptors' in the uterus and hypothalamus of female rats are highly specific for progestins, which they bind with high affinity (Kd for [3H]progesterone in hypothalamus is 1.9 nM and in uterus is 3.7 nM). The dissociation of [3H]progesterone from receptor in vitro is rapid: t1/2 6 degrees C = 45 min in uterine cytosol; t1/2 6 degrees C = 160 min in hypothalamic cytosol. The binding is destroyed by proteinase. In the cytosol of hypothalamus and cortex of developing rats, progestin 'receptors' were present in both male and female rats by 2-3 days after birth; subsequent changes in concentration of these 'receptors' appeared to be independent of sex. Concentrations of progestin 'receptor' were close to adult values by 8-9 days, and thereafter changed relatively little.

Animals↗
PubMed1978

Intracellular relationships of the oestrogen receptor in the rat uterus and hypothalamus during the oestrous cycle.

Simultaneous measurements were made of the specific oestrogen receptor in the nuclear and cytosol fractions prepared from the uterus and hypothalamus of 50--81-day-old female rats undergoing a 4-day oestrous cycle. In the uterus, the content of nuclear receptor fluctuated in concert with known cyclic changes in the secretion of oestrogen, being maximal at pro-oestrus. Over the period of 50--81 days, the nuclear content at all phases increased with age, again corresponding to known age-related increases in ovarian secretion of oestrogen. This age-related increase in nuclear content, averaged from the values of the different phases in each age group, was related to equivalent increases in uterine wet weight, an increase of 1 pmol of receptor being accompanied by an increase of 80--90 mg. The concentration of cytosol receptor was maintained constant, with respect to wet weight, throughout the cycle and with age, irrespective of changes in nuclear content. In the uterus of normal mature females, translocation of receptor into the nucleus did not lead to depletion of cytosol receptor, suggesting a process of continuous replenishment/synthesis. In the hypothalamus, the nuclear content of oestrogen receptor was also maximal at pro-oestrus. In contrast with the uterus, the content of hypothalamic cytosol receptor was minimal at this phase and reflects depletion of the cytosol receptor, possibly as a result of translocation. The extent of translocation was low compared with that in the uterus and did not alter with age during the age-period studied. This low nuclear binding of the receptor in vivo is discussed in relation to the presence of a cytosol factor, present in limiting amounts, which in vitro mediates the binding of cytosol receptor to oligo(dT)-cellulose. The difference in the physiological response of the uterus and of the hypothalamus to oestrogens may be related to the extent of nuclear binding of receptor.

Animals↗
PubMed1976

The selective isolation of the uterine oestradiol-receptor complex by binding to oligo(dT)-cellulose. The mediation of an essential activator in the transformation of cytosol receptor.

The [3H]oestradiol-receptor complex was selectively isolated from rat uterus cytosol by column chromatography on oligo(dT)-cellulose. Optimal conditions are described for the binding of the complex to oligo(dT)-cellulose, which is shown to be similar to its binding to DNA-cellulose. The cytosol complex has an apparent mol. wt. of 50,000-60,000 in high salt concentrations, as determined by Sephadex G-100 chromatography. This corresponds to the 4S cytoplasmic oestradiol receptor. In binding to oligo(dT)-cellulose the receptor is transformed into a form with an apparent mol.wt. of 100,000-120,000, corresponding to the 5S nuclear receptor complex. This transformation mimics the conversion in vivo of the cytoplasmic oestradiol receptor into the nuclear form. The binding of the complex to oligo(dT)-cellulose as a 5S nuclear form is unequivocally demonstrated to require the mediation of an activating present in the cytosol. The requirement for an activating factor is discussed in relation to reports that nuclear binding of the oestradiol-receptor complex is not dictated solely by the availability of the cytoplasmic oestradiol receptor.

Animals↗