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Biomedical subjects

P Miranda

Publications and source records attributed to P Miranda.

At least 73 records · Page 4Linked to original sources
PubMed1987

Expression of bovine rotavirus neutralization antigen in Escherichia coli.

A 646 bp fragment derived from a full length cDNA clone of genomic segment 9 of bovine rotavirus (NCDV strain) was inserted into Escherichia coli expression plasmid pEX1. The fragment encodes amino acids 50 to 265 of the major vital neutralization antigen VP7, a 326 amino acid long outer shell glycoprotein. Several transformed bacterial clones were isolated in which the recombinant plasmid directed the synthesis of a cro-beta-galactosidase-VP7 fusion protein that was recognized by rabbit polyclonal antibodies against NCDV rotavirus. Sera from rabbits immunized with the fusion protein specifically reacted with VP7 among NCDV virion polypeptides. The chimeric polypeptide was also specifically recognized by two monoclonal antibodies against UK strain rotavirus VP7 that exhibited virus-neutralizing activity. However, immune sera to the chimeric polypeptide showed no neutralizing activity against bovine rotavirus. These results are discussed in view of a recent report that a fusion VP7-beta-galactosidase polypeptide comprising 35 more amino acids at the carboxy terminus was able to induce neutralizing antibodies in mice to simian rotavirus SA11.

Animals↗
PubMed1985

Fertility regulation in nursing women: VII. Influence of NORPLANT levonorgestrel implants upon lactation and infant growth.

The objective of this study was to test the influence of NORPLANT implants upon lactation and infant growth. The results obtained during the first postpartum year are reported. One-hundred women were enrolled in the implant group. The control group was formed by 100 women who received a Copper T IUD. Treatments were administered at day 55 +/- 3. At admission all subjects were in exclusive breastfeeding with an adequate weight increase of the infant. No significant differences were found between the treated and control groups in the percentage of women in full nursing at different postpartum intervals, except for the 12th month postpartum where a lower percentage of cases from the NORPLANT group was in the full nursing category. No difference was found in the time of weaning. The infants showed a normal weight gain rate in both groups although the girls from the NORPLANT group showed a significantly lower daily weight increase during the 4th month than the girls from the IUD group. No pregnancies were diagnosed. No women asked for implant removal during the first year. No serious side effects related to treatment were detected. Bleeding irregularities were rare during breastfeeding which is in contrast with what occurs in non-nursing women treated with NORPLANT implants. Levonorgestrel concentrations found in milk were variable and individual values ranged from 23 to 311 pg/ml. The dose received by the infant can be estimated around 15 to 18 ng/Kg/day during the first month of treatment when the higher plasma values of levonorgestrel are observed. These levels is conjunction with the clinical observations reported here minimize the potential problems associated with levonorgestrel transference through maternal milk. Nevertheless, long-term studies are required to settle this matter and until more information is available, NORPLANT implant use in lactating women should be limited to cases who require a highly effective contraceptive method and where non-hormonal methods of similar effectiveness are contraindicated or unacceptable.

Adolescent↗
PubMed1985

Fertility regulation in nursing women: VIII. Progesterone plasma levels and contraceptive efficacy of a progesterone-releasing vaginal ring.

The objectives of this trial were to test the contraceptive efficacy and measure progesterone plasma levels of women using progesterone-releasing rings during lactation. Two types of rings delivering an average of about 5 mg or 10 mg of progesterone per day were tested in 128 healthy nursing women. A control group was formed by 127 Copper T users. Rings were inserted at day 60 postpartum and replaced every 3 months with a new one. Initially progesterone plasma levels were around 10 nmol/l and 15 nmol/l for rings releasing 5 and 10 mg per day, respectively, and decreased slightly after 30 days. Levels observed in subsequent segments of use approximated those of the first segment. These levels are within the range shown to inhibit fertility in lactating women. One pregnancy was diagnosed in 739 woman-months of progesterone ring use, and none occurred in 794 woman-months of Copper T use, which contrasts with the high incidence of pregnancy in a group of untreated nursing women where 19 pregnancies resulted during 677 woman-months. No deleterious effects were detected lactation and infant growth or maternal and infant health. It is concluded that the vaginal rings releasing progesterone are a suitable contraceptive method for lactating women.

Clinical Trials as Topic↗
PubMed1984

Fertility regulation in nursing women. VI. Contraceptive effectiveness of a subdermal progesterone implant.

Six progesterone pellets implanted subdermally were tested as contraceptive method for lactating women. One pregnancy was diagnosed in 1614 woman-months of observation, a failure rate which was similar to that observed in a contemporary group of Copper T users. Nineteen pregnancies were diagnosed in the 677 woman-months observed in untreated lactating women. The progesterone implants were effective when administered either at 30, 60 or 240 days after delivery. The duration of the effective life was 5 months and fertility was quickly restored afterwards. There were no deleterious effects upon maternal or infant health or upon lactation and the rate of child growth. The main problem encountered was the occurrence of pellet expulsion at a variable rate which appeared related to the manufacturing procedure.

Adolescent↗
PubMed1983

Fertility regulation in nursing women: III. Short-term influence of a low-dose combined oral contraceptive upon lactation and infant growth.

The study was designed to test the short-term influence of a low-dose combined oral contraceptive upon lactation and infant growth when treatment was initiated at day 30 postpartum. The contraceptive tested contained ethinyl estradiol 0.03 mg and levonorgestrel 0.15 mg. Two control groups were formed by women who received either an oral placebo or an injectable placebo at day 30 postpartum. An exacting list of requirements for admission and continuation in the study was applied to all groups. The oral contraceptive group had a lower percentage of cases in exclusive breastfeeding at day 91 postpartum when compared to both control groups. Infants in the oral contraceptive group showed a significantly lower average absolute weight at days 61 and 91 postpartum and a significantly lower average daily weight increase during the first month of treatment when compared to both control groups. It was concluded that the oral contraceptive tested had a negative influence upon lactation and child growth.

Adult↗
PubMed1983

Fertility regulation in nursing women: IV. Long-term influence of a low-dose combined oral contraceptive initiated at day 30 postpartum upon lactation and infant growth.

The study was designed to test the long-term influence of a low-dose combined oral contraceptive upon lactation and infant growth when treatment was initiated at day 30 postpartum. The contraceptive tested contained ethinyl estradiol 0.03 mg and levonorgestrel 0.15 mg. Two control groups were formed by women who received an injectable placebo or a Copper T at day 30 postpartum. Women in the injectable placebo group received non-hormonal contraceptives at day 90 postpartum. An exacting list of requirements for admission and continuation in the study was applied to all groups. The oral contraceptive group had a significantly lower percentage of cases in full nursing from the 4th through the 10th postpartum month when compared to both control groups. The average absolute weight of infants in the oral contraceptive group was significantly lower at several ages when compared to the placebo group but not when compared to the Copper T group. No adverse side effects upon infant's health were detected. It was concluded that the oral contraceptive tested showed a moderate inhibitory influence upon lactation when treatment was initiated at the beginning of the second postpartum month.

Adult↗
PubMed1983

Fertility regulation in nursing women: V. Long-term influence of a low-dose combined oral contraceptive initiated at day 90 postpartum upon lactation and infant growth.

The study was designed to test the long-term influence of a low-dose oral contraceptive upon lactation and infant growth when treatment was initiated at day 90 postpartum. The contraceptive tested contained ethinyl estradiol 0.03 mg and levonorgestrel 0.15 mg. The control group was formed by women who chose non-hormonal contraception at the same postpartum time. Only cases who were in exclusive breast-feeding with a minimal infant daily weight increase of 20 g per day during the third month of age were included. The oral contraceptive group showed a significantly lower percentage of cases in full nursing from the 6th postpartum month and a significantly lower infant weight increase during the 4th month of age when compared to the control group. No differences were found in the absolute infant weight up to one year of age. No adverse side effects upon infant's health were detected. It was concluded that the oral contraceptive tested showed a moderate inhibitory influence upon lactation when treatment was initiated at day 90 postpartum.

Adult↗
PubMed1982

A five-year clinical trial of levonorgestrel silastic implants (Norplant TM).

Silastic implants containing the progestin, levonorgestrel, were tested as a long-term contraceptive system in 101 women. During five full years of use, no pregnancies occurred. The 5-year continuation rate was 54%. Menstrual irregularities were the most frequent reason for termination of use but only during the first year. More than half of the terminations for this reason were in the first year. Some of the subjects elected to continue use of the implants beyond 5 years, allowing release rate data to be obtained through 6 years. From the second through the sixth year of use, the implants delivered a constant 30 micrograms per day of levonorgestrel to the subjects, and even after six years 57% of the original steroid content remained in the capsules. Return of fertility following removal was essentially immediate and not related to time of use. Medical reasons for removal were infrequent and no pattern was discernible.

Adult↗
PubMed1982

Plasma progesterone levels during long-term treatment with levonorgestrel silastic implants.

Plasma progesterone levels were measured in 113 women using a subdermal implant containing 200 mg levonorgestrel (NORPLANT) in an attempt to assess the roles of anovulation and inadequate luteal function in the contraceptive action of this method. Twenty-two women using an IUD (Copper T 200) served as a control group. Blood samples were taken twice a week for 6 consecutive weeks. This was done one to four times in each subject during the first 7 years after insertion of NORPLANT. Plasma progesterone was measured by a specific RIA and criteria based upon normal values in this laboratory were used to define each set of samples as ovulatory, uncertain or anovulatory. The rate of anovulation varied between 25 and 80% throughout the 7 years. The highest rate was observed during the first year of treatment of treatment. The rate of anovulation was significantly correlated with the plasma levels of levonorgestrel. Varying degrees of inadequate corpus luteum function were detected among NORPLANT users. All sets of samples in the control group were ovulatory and compatible with normal luteal function. These results clearly show that continuous administration of levonorgestrel by means of NORPLANT interferes with ovulation and/or luteal function in a significant proportion of cycles throughout the first 7 years of use.

Adult↗
PubMed1981

Plasma levels of levonorgestrel in women during longterm use of norplant.

Levonorgestrel plasma levels were determined by a specific radioimmunoassay in a group of 110 women at various intervals between 1 and 60 months following implantation of six silastic capsules containing levonorgestrel (Norplant). The implants were placed subdermally in the volar aspect of the forearm. Blood samples were taken twice a week for six consecutive weeks in each subject. Blood drawn from the antecubital vein ipsilateral to the implant site contained two to three times more levonorgestrel than contralateral samples. Average systemic plasma levels represented by contralateral samples ranged from 0.35 +/- 0.03 to 0.29 +/- 0.02 ng/ml (Mean +/- S.E.) in the first and fifth year, respectively. The difference between these values is statistically significant at the 5% level. The results of the regression analysis of individual levels suggest that the decline observed throughout the first five years is mainly due to an early decrease taking place in the first two years. When the sampling period was repeated in the same subjects two or three times 10 to 24 months apart, no significant difference was found. A significant negative correlation was found between plasma levonorgestrel levels and body weight and body surface. The data indicate that the contraceptive efficacy of Norplant during the first five years of use is associated with sustained release of levonorgestrel and is in keeping with the estimated life span of Norplant of seven years.

Female↗
PubMed1980

Plasma levels of levonorgestrel in women during longterm use of Norplants.

Levonorgestrel plasma levels were determined by a specific radioimmunoassay in a group of 110 women at various intervals between 1 and 60 months following implantation of six silastic capsules containing levonorgestrel (Norplant). The implants were placed subdermally in the anterior aspect of the forearm. Blood samples were taken twice a week for six consecutive weeks in each subject. Blood drawn from the antecubital vein ipsilateral to the implant site contained two to three times more levonorgestrel than contralateral samples. Average systemic plasma levels represented by contralateral samples ranged from 0.35 +/- 0.03 to 0.29 +/- 0.02 ng/ml (Mean +/- S.E.) in the first and fifth year, respectively. The difference between these values is statistically significant at the 6% level. The results of the regression analysis of individual levels suggest that the decline observed throughout the first five years is mainly due to an early decrease taking place in the first two years. When the sampling period was repeated in the same subjects two or three times 10 to 24 months apart, no significant difference was found. A significant negative correlation was found between plasma levonorgestrel levels and body weight and body surface. The data indicate that the contraceptive efficacy of Norplants during the first five years of use is associated with sustained release of levonorgestrel and is in keeping with the estimated life span of Norplants of seven years.

Adult↗