Evidence for a modulation of the stress response by the pineal gland.

Wistar rats show a circadian variation in their response to stress. Pinealectomy exacerbates stress-induced gastric ulceration in rats. This effect is counteracted by melatonin administration.

Influence of blood clots in the cumulus complex on oocyte fertilization and cleavage.

Since multiple ovarian punctures are performed during oocyte retrieval, the likelihood of blood contaminating the follicular fluid is high. The purpose of this study was to determine whether the presence of blood clots, which are frequently seen in the cumulus of oocytes retrieved under ultrasound guidance, has any effect on fertilization and subsequent embryo cleavage and to identify oocyte characteristics which may predict these events. Oocytes were morphologically graded and the presence of blood clots in the cumulus was recorded.

A 'silent' intracranial complication of frontal sinusitis.

Intracranial complications of frontal sinusitis, although rare today, do still develop despite widespread use of antibiotics. We report a case which demonstrates how silently a frontal lobe abscess may present with subtle changes in mood and behaviour, with no focal neurological signs. Diagnosis and management are discussed and a brief review of the incidence of intracranial complications of frontal sinusitis, mode of spread, clinical presentation, investigations, treatment and bacteriology is presented.

Melatonin counteracts the 5-aminolevulinic acid-induced rise of rat forebrain tryptophan and serotonin concentrations at night.

When rats were exposed to extended light into the normal dark phase, the administration of 5-aminolevulinic acid (5-ALA) markedly stimulated the accumulation of tryptophan (TRP) and the synthesis of serotonin (5-HT) in the forebrain. When a single injection of melatonin (25 micrograms) was given near the end of the 5-ALA treatment, the rise in forebrain TRP levels was either totally prevented or reversed; likewise, the increased levels of 5-HT were also suppressed. Melatonin by itself also slightly suppressed forebrain TRP levels in non-5-ALA-treated rats.

Pineal gland as a model to elucidate the primary mode of action of alpha-methyldopa: alpha-methyldopa induces an increase in the synthesis of N-acetylserotonin and melatonin levels by the rat pineal gland.

An attempt was made to use the pineal gland as a model for the study of the primary mode of action of alpha-methyldopa, which is still unclear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radio-active serotonin to melatonin (aMT) as well as its precursor, N-acetyl-serotonin (aHT). This treatment was also found to raise serotonin-N-acetyltransferase (NAT) activity.

Identification of low molecular weight immunosuppressor molecules in human in vitro fertilization supernatants predictive of implantation as a polyamine--possibly spermine.

Suppressor activity in in vitro fertilization (IVF) culture medium correlates with successful implantation. High performance liquid chromatography fractionation revealed peak(s) of inhibitory activity in the 1,000- to 5,000-Da molecular weight range. Inhibitory activity was dependent on the presence of fetal bovine serum (FBS) and was abrogated both by heat treatment of the serum and by pretreatment with monoamine oxidase inhibitors.

Protein-ligand interactions: interaction of nitrosamines with nicotinic acetylcholine receptor.

Fluorimetry and spectrophotometry have been used to study the binding of dimethyl, dipropyl, dibutyl and diphenylnitrosamine to nicotinic acetylcholine receptor isolated, and purified, from Torpedo fuscomaculata. Scatchard analysis indicates that all four ligands are true agonists of the receptor exhibiting positive cooperative binding with the existence of more than one class of binding site. The number of binding sites for the nitrosamines approximates 2.

The effect of melatonin on the formation of gastric stress lesions in rats.

Prior melatonin administration (1,5 and 10 mg/kg b. wt) causes a significant reduction in gastric ulceration induced in male rats by restraint immobilization in the presence of low temperatures.

Effect of 6-methoxy-2-benzoxazolinone on the activities of rat pineal N-acetyltransferase and hydroxyindole-O-methyltransferase and on melatonin production.

A naturally occurring compound, 6-methoxybenzoxazolinone (6-MBOA), present in grasses, has been shown to induce sexual maturation in a number of rodent species. The structural similarity of 6-MBOA and melatonin has led researchers to suspect that 6-MBOA might induce its progonadal effects by directly altering pineal function. Previous studies have shown that 6-MBOA has the properties of a weak beta-adrenergic agonist capable of stimulating rat pineal N-acetyltransferase (NAT) activity at pharmacological concentrations of 10(-3) M.

Semen predictors of in vitro fertilization and embryo cleavage.

In vitro fertilization treatment for male infertility is not very successful because fertilization is known to be affected by semen quality. Information on fertilizing ability may provide prognostic information for couples contemplating such treatment. The purpose of this study was to identify semen variables that would predict fertilization and embryo cleavage.

Optimal time in the menstrual cycle for serum progesterone measurement to diagnose luteal phase defects.

Inadequate production of progesterone by the corpus luteum results in luteal phase deficiency, which is a frequent cause of recurrent spontaneous abortion. The diagnosis is made by assessment of endometrial biopsy specimens. Measurement of serum progesterone offers a less invasive alternative, but its utility as a diagnostic test is limited since there is no agreement on the level that will accurately differentiate between normal and luteal phase deficiency cycles.

Diagnosis of acute appendicitis in pregnancy.

Although the clinical diagnosis of appendicitis in pregnancy seems to be complicated by the physiologic changes of pregnancy, evidence from controlled studies is lacking. The aims of this study were to determine whether there are any features of appendicitis in pregnant women that would help to establish the diagnosis and whether any difference exists between the presentation of appendicitis in pregnant and nonpregnant women. Twenty-eight pregnant women with a clinical diagnosis of appendicitis were compared with an equal number of nonpregnant patients matched for age and randomly selected from a group of patients who had appendicitis.

Heme precursor 5-aminolevulinic acid alters brain tryptophan and serotonin levels without changing pineal serotonin and melatonin concentrations.

The daytime administration of the heme precursor 5-aminolevulinate (5-ALA) has been shown to reduce brain tryptophan and serotonin levels owing to saturation of liver tryptophan pyrrolase. Saturation of this enzyme with heme results in enhanced activity, leading to increased catabolism of tryptophan and thus making less tryptophan available to the brain. Tryptophan is also the precursor of melatonin, a primary secretory product of the pineal gland.

Investigation of the infertile couple.

Although the exact incidence of infertility in Canada is unknown, mathematical models predict that approximately 10% to 15% of couples will fail to achieve a pregnancy after one year of unprotected intercourse. The diagnosis requires assessment of both male and female partners. During the initial visit, a comprehensive history should be elicited and a thorough physical examination performed.

Efficacy of progesterone support for pregnancy in women with recurrent miscarriage. A meta-analysis of controlled trials.

Progesterone appears to be necessary to support an early pregnancy, and it has been used for this purpose for several decades. Its potential role in women with recurrent miscarriage due to luteal phase deficiency has been suggested, but its efficacy has not yet been demonstrated. Three controlled trials of progesterone treatment in women with recurrent miscarriage have shown small, but not statistically significant, increases in the rates of pregnancies that continue beyond 20 weeks in the treated groups.

Immunosuppressive activity in human in vitro fertilization (IVF) culture supernatants and prediction of the outcome of embryo transfer: a multicenter trial.

The supernatants from cultured human oocytes fertilized in vitro contain low molecular weight factors that can suppress or stimulate the proliferative response of lymphocytes in vitro. The inhibitory and stimulatory effects are nonspecific and may be detected using cultured human or murine tumor cell lines. Using such a bioassay, we previously tested fetal cord serum-supplemented culture supernatant and found that an absence of suppression was correlated with an absence of subsequent pregnancy.

Trophoblast induction of suppressor-type cell activity in human endometrial tissue.

First trimester (10-12 weeks gestation) human decidua contains small lymphocytic suppressor cells that release 22 and 43 kd soluble suppressor factors blocking the action of interleukin 2. Luteal phase endometrium, in contrast, contains large suppressor cells that do not release soluble immunosuppressive factors. However, if luteal phase endometrium from days 24 to 25 of the menstrual cycle is incubated with placental syncytiotrophoblast membrane vesicles, suppressor factors having the same molecular weight as those found in end of first-trimester pregnancy decidua are released into the supernatant.

Follicular fluid pH changes following intraperitoneal exposure of Graafian follicles to carbon dioxide: a comparative study with follicles exposed to ultrasound.

Follicular aspiration to obtain oocytes is generally performed via laparoscopy after creating a pneumoperitoneum with carbon dioxide. Such a procedure has been shown to reduce the rate of in-vitro fertilization of human oocytes and affect the rate of cleavage of rabbit embryos. These adverse effects may be caused by a reduction in follicular fluid pH due to diffusion of carbon dioxide into the follicle.

Efficacy of progesterone support in the luteal phase following in-vitro fertilization and embryo transfer: meta-analysis of clinical trials.

The question of whether follicular aspiration of oocytes alters the quality of the luteal phase remains unanswered. Progesterone appears to be necessary for implantation and maintenance of an early intrauterine pregnancy and this partly has been the basis for recommending luteal phase supplementation with progesterone following oocyte retrieval. Although small increases in pregnancy rates were observed in several trials, such support with progesterone was not efficacious.

Progesterone profiles in luteal phase defect cycles and outcome of progesterone treatment in patients with recurrent spontaneous abortion.

The existence of luteal phase defect has been the focus of much debate, mainly because of inconsistencies in its diagnosis and management. This study was performed to compare progesterone profiles in women with luteal phase defect with those of women with normal cycles and to establish a discriminatory level of serum progesterone that may aid in the diagnosis of this condition. Compared with patients with luteal phase defect cycles, women with normal cycles produced significantly more progesterone in the luteal phase.

Identification of two species of suppressive factor of differing molecular weight released by in vitro fertilized human oocytes.

Preimplantation human embryos have been shown to release factors that have immunosuppressive activity and that are highly correlated with successful implantation. The present study was undertaken to determine the molecular weight of these factors using HPLC. Two peaks of suppressive activity were found associated with molecular weights of 3.

Diagnostic test properties of serum progesterone in the evaluation of luteal phase defects.

The existence of LPD has been controversial, mainly because of inconsistencies in its diagnosis. The endometrial biopsy remains as a gold standard until newer and better tests are developed. Additional information may be provided from serum P determinations in the luteal phase by using the likelihood ratios and positive predictive values obtained in this study.

Fertilization and embryo development of oocytes obtained transvaginally under ultrasound guidance.

The widespread use of ultrasound for follicle development assessment and ovum pickup has raised concerns about the theoretical possibility of adverse effects on oocyte function. Studies in other species do not demonstrate any adverse effects when using sonic energies as those presently used in diagnostic ultrasound. However, no data are available concerning the effects of diagnostic ultrasound on human preovulatory oocytes.

Effect on fertilization of intra-peritoneal exposure of oocytes to carbon dioxide.

Follicular aspiration is generally performed via laparoscopy after creating a pneumoperitoneum with carbon dioxide (CO2). Adverse effects on embryo development may occur following exposure to CO2, which is known to cause a decrease in follicular fluid pH. Such a reduction in pH may affect fertilization and early embryonic development and this study was carried out to study these effects.