Biomedical subjects

S Díaz

Publications and source records attributed to S Díaz.

At least 37 records · Page 2Linked to original sources

PubMed1999

Norplant((R)) implants and progesterone vaginal rings do not affect maternal bone turnover and density during lactation and after weaning.

Bone density and turnover was assessed in a longitudinal study of healthy lactating women who initiated use of Norplant((R)) implants (NOR, n = 29), progesterone vaginal rings (PVR, n = 28) or Copper T 380A intrauterine devices (T-Cu, n = 51, control group) around day 60 postpartum. Bone density, serum calcium, phosphorus, alkaline phosphatases, parathyroid hormone (PTH), follicle stimulating hormone (FSH), oestradiol and prolactin, and urinary hydroxyproline and creatinine were measured at postpartum months 1 (PM1), and 12 (PM12) and 6 or 12 months after weaning; at month 6 postpartum (PM6) serum and urine tests alone were performed. Baseline characteristics and lactation performance were similar between groups. Biochemical markers of bone turnover were higher at PM1, PM6 and PM12 than after weaning, with no differences between groups. Bone density in the lumbar spine (L2-L4) and femoral neck at PM1 and PM12 ( approximately 1.11 g/cm(2)) was similar in three groups. Lumbar spine values were found to be lower in lactating women than those present in non-lactating women, but increased after weaning to similar values. The two progestin-only contraceptives studied appear to have no deleterious effect upon bone density and metabolism in healthy lactating women.

Administration, Intravaginal↗

PubMed1999

Bioactivity of prolactin isoforms: lactation and recovery of menses in nursing women.

To assess whether plasma prolactin (PRL) characteristics relate to lactogenesis and absence or presence of menstrual cycles, we measured bioactive PRL (BIO-PRL) using the Nb2 assay, immunoreactive PRL (IR-PRL) by radio-immunoassay, calculated equations describing the BIO-PRL-IR-PRL relationship and separated charged PRL isoforms (by chromatofocusing) in five amenorrhoeic and five cycling nursing women at 6 months postpartum and in 10 cycling non-nursing women. Plasma samples were drawn before and 30 min after a suckling episode at 0800, 1600 and 2400 h in nursing women and at the same hours in non-nursing women. BIO-PRL and IR-PRL concentrations were highest in amenorrhoeic nursing women, intermediate in cycling nursing women and lowest in cycling non-nursing women. The BIO-PRL-IR-PRL relationship shows that a given amount of IR-PRL corresponds to equivalent amounts of BIO-PRL in cycling nursing and cycling non-nursing women, and to a larger extent in amenorrhoeic nursing women. IR-PRL was present in plasma as several charge isoforms. Bioactive isoforms eluting at pH 6.0-5.1 were found in amenorrhoeic and cycling nursing women, reaching similar concentrations after suckling. Bioactive isoforms eluting at pH 7.0-6.1 were found only in amenorrhoeic nursing women. We speculate that isoforms eluting at pH 6.0-5.1 may play a role in lactation and isoforms eluting at pH 7.0-6.1, in lactational amenorrhoea.

Adult↗

PubMed1999

Integrated maternal and infant health care in the postpartum period in a poor neighborhood in Santiago, Chile.

An integrated postpartum health-care program was established by the Consultorio San Luis de Huechuraba (CSLH), a nongovernmental organization in a neighborhood of extreme poverty in Santiago, Chile. The main components were education, maternal and infant health care, support for the mothers, and active participation of women from the community served. The program was evaluated through indicators of contraceptive use, breastfeeding performance, infant growth and health, and a qualitative assessment of women's satisfaction. Controls were women of similar characteristics attending the nearby public clinic. Acceptability of contraceptive methods was similar but contraceptive options differed between clinics. The total number of pregnancies and of respondents lost to follow-up was significantly higher for the public clinic than for the CSLH. Breastfeeding duration was significantly longer and infant growth and health were found to be significantly better at the CSLH than at the public clinic. Women valued being treated with respect, receiving education and support, and being offered timesaving services and wider contraceptive choices at the CSLH. This study demonstrates that such interventions are possible for poor communities, providing significant advantages for women and children.

Adult↗

PubMed1999

Beneficial effects of diphenhydramine in dystonia.

The objective of this paper was to evaluate the efficacy of diphenhydramine hydrochloride (DPH) in dystonic patients. In 1995, Truong et al reported encouraging results in five patients with idiopathic torsion dystonia (ITD) treated with DPH, an H1 antagonist with sedative and anticholinergic properties. Five patients with generalized ITD, one with secondary generalized dystonia and one with idiopathic segmental dystonia were included in the prospective study. Initially the response to intravenous administration of DPH versus placebo in two sessions a week apart was evaluated. Two weeks later all patients started oral DPH in increasing doses (range 100-300 mg, mean 164 mg). The degree of dystonia was determined by a modified University of Columbia Scale evaluating the baseline score, after placebo and DPH I.V. administration then at one and six months after starting oral treatment. The results were analyzed by Friedman's test for repeated measurements. On comparing scores for baseline severity, I.V. placebo and I.V. DPH presented a highly significant correlation (12.09; p = 0.00) as well as comparing baseline score with oral DPH at one and 6 months, treatment (12.78; p = 0.00). Functional score results were 9.5 p = 0.01 and 8.4 p = 0.02 at one and 6 months respectively. The most common side effects were somnolence and dizziness. It can be concluded that DPH proved effective in our patients with mild to moderate adverse effects not requiring drug withdrawal in any case. However, I.V. challenge was unable to predict the long-term response to oral medication perhaps due to the limited number of cases.

Adolescent↗

PubMed1998

Inertia and Resilience in the Responses of the Aquatic Bryophyte Fontinalis antipyretica Hedw. to Thermal Stress

The physiological responses of the aquatic bryophyte Fontinalis antipyretica Hedw. to high temperatures, ranging from 16 degreesC (control) to 34 degreesC, were investigated experimentally. Plant samples were maintained at the temperature under study for up to 25 days with regular determination of physiological variables (pigment ratio and photosynthetic and respiratory rates). Physiological responses to temperature did not differ significantly between mosses collected from a normal river site and from a river site with abnormally high temperature due to input from a hot spring. Simple curve-fitting procedures and summary statistics analogous to those used in toxicological research were employed to compare responses as revealed by the different physiological variables. In a second series of experiments, the capacity of F. antipyretica to recover from high-temperature stress was investigated by maintaining samples at 30 degreesC for 2, 4, or 10 days, then transferring the samples to normal conditions (16 degreesC) for 40 days. Physiological variables were again monitored at regular intervals throughout both phases of the experiment. In general, good recovery was observed even after exposure to high temperatures for 10 days. The results of these assays allow quantification of the relationship between a pigment ratio and net photosynthesis rate.

Journal Article↗

PubMed1998

Contraceptive technology and family planning services.

A large variety of modern contraceptives is now available, including several means to administer hormonal contraception, highly effective long-term methods and simple sterilization techniques. Methods under research include immuno-contraceptives for women and men, hormonal methods for men, new approaches to female hormonal contraception and improved barrier methods. Modern contraceptives are effective and safe for most women, and some methods have beneficial health effects other than prevention of pregnancy. However, underlying health conditions may decrease the safety of a given method. The appropriate use of the technology available requires screening for biomedical conditions and counseling that enables the selection of methods according to the life style of women and couples. Contraceptive methods have had a considerable positive impact on maternal and infant health and on population growth, but unwanted pregnancies and unsafe abortion still occur in large numbers. This shows the need to improve access to and quality of family planning services including the availability of contraceptives, sensitive providers trained in technical matters and communication skills, and communication between the community, the providers and the managers.

Chile↗

PubMed1997

Contraceptives for lactating women: a comparative trial of a progesterone-releasing vaginal ring and the copper T 380A IUD.

From approximately one week before normal ovulation resumes, lactating women require protection against pregnancy by a contraceptive that is safe for both infant and mother in a multicenter one-year study, the natural hormone, progesterone, delivered vaginally by a sequence of four contraceptive rings designed for continuous use, was evaluated as a contraceptive for nursing mothers in comparison with the Copper T 380A IUD. Individual rings release in effective average dose of 10 mg day for a 3 month period. Evaluation included measures of lactational performance as well as of contraceptive efficacy and safety to mother and child. Nine participating clinics enrolled 802 ring users and 734 IUD acceptors between postpartum days 29 and 63. Life table analyses were performed with parallel decrements for ring and IUD subjects. Continuation in the study and analysis required that subjects not stop breastfeeding. The ring, with a one-year pregnancy rate of 1.5 per 100, did not differ significantly from the IUD with respect to contraceptive effectiveness (p > 0.05). More than half of the ring subjects were continuing at 6 months post admission and a quarter (23.5 per hundred) were still using the ring and breastfeeding one year after admission. Women with the IUD, however, had higher continuation rates (p < 0.001) at both time points. The largest single decrement for each method was that for weaning. Ring users had more complaints of vaginal problems but had fewer vaginal disorders on examination. At 12 months postpartum, 46 per 100 continuing ring users remained in amenorrhea. Lactation performance and the health and weight gain of the infants were similar among users of either regimen.

Administration, Intravaginal↗

PubMed1997

Fertility regulation in nursing women. IX. Contraceptive performance, duration of lactation, infant growth, and bleeding patterns during use of progesterone vaginal rings, progestin-only pills, Norplant implants, and Copper T 380-A intrauterine devices.

This study evaluated the performance of progesterone vaginal rings (n = 187), progestin-only pills (n = 117), Norplant implants (n = 120), and Copper T 380-A intrauterine devices (n = 122) in lactating women. Contraceptive efficacy, bleeding pattern, and influence of the method upon breastfeeding duration and infant growth were compared with those of untreated women (n = 236) who relied on lactational infertility. Participants were healthy, 18 to 38 years, had had a normal delivery, and were intending to breastfeed for as long as possible. Contraceptives were initiated at day 57 +/- 3 postpartum. Results are reported for the first year of use. All methods were highly effective, with pregnancy rates below 1%. None affected breastfeeding performance or the rate of infant growth. Users of the progestin-only methods experienced a period of lactational amenorrhea 4 to 5 months longer than did users of Copper T or untreated women. More than half of the women in each contraceptive group reported a bleeding in the first month after treatment initiation, which was not considered in the calculation of the duration of amenorrhea. Prolonged or frequent bleedings were infrequent. The proportion of bleedings lasting more than 10 days ranged from 0 in the progestin-only pills group to 7% in the Norplant implants group. The four methods, initiated around the eighth postpartum week, provided effective contraception with no negative effects upon lactation or infant growth and without the bleeding problems associated with their use in nonlactating women.

Adult↗

PubMed1997

Post-suckling prolactin:oestradiol ratio--a potential index to predict the duration of lactational amenorrhoea in women.

To assess whether the duration of lactational amenorrhoea can be predicted in individual women, we studied the pre- and post-suckling concentrations of immune prolactin (IR-PRL) and of bioactive prolactin (BIO-PRL) and basal concentrations of oestradiol in ten amenorrhoeic fully nursing women at 3 months post-partum. The women were of similar age, weight and had infants of similar growth rate. Five of these women were to experience long amenorrhoea (>180 days) and the others short amenorrhoea (<180 days). Blood samples were drawn 30 min after a suckling episode initiated at 0800 h, 1600 h and 2400 h. BIO-PRL distinguished between groups of women at 0030 h but not at other times, while there was considerable overlap between values for IR-PRL and oestradiol at all times studied. At 1630 h, the ratios post-suckling BIO-PRL: oestradiol and post-suckling IR-PRL:oestradiol were above 2000 in the women that were to experience long amenorrhoea and below this threshold in the other women. The ratio post-suckling BIO-PRL:oestradiol provided more information since the difference between the lowest ratio in the long amenorrhoea and the highest ratio in the short was 699, while it was 520 for the IR-PRL:oestradiol ratio. The determination of these ratios may help to predict the duration of lactational amenorrhoea in individual fully nursing women.

Adult↗

PubMed1996

Bone turnover and density in healthy women during breastfeeding and after weaning.

To investigate the changes in maternal bone density and turnover associated with lactation we ran a longitudinal study in fully breastfeeding women (age 26.3 +/- 4.1 years, mean +/- SD) at the first (stage I, n = 30) and sixth (stage II, n = 25) months postpartum and 6 months after weaning (stage III, n = 20), and in a contemporary control group of non-nursing women. At each time point bone density, serum calcium, phosphorus, alkaline phosphatases, parathyroid hormone (PTH), osteocalcin, follicle stimulating hormone (FSH), estradiol (E2), prolactin (PRL) urinary hydroxyproline and creatinine (OH-P/Cr) were measured in both groups. The daily calcium intake of nursing women (1479 +/- 590 mg/day at stage I) was higher than in non-nursing women (536 +/- 231 mg/day at stage I). Biochemical markers of bone turnover were higher (p < 0.05) in nursing than in non-nursing women at stages I and II, while in stage III only OH-P/Cr was elevated. The lumbar spine (L2-4) bone mineral density was similar in the two groups at the beginning of the study (1.148 +/- 0.111 g/cm2 in nursing women vs 1.211 +/- 0.102 g/cm2 in non-nursing women; p = 0.06), but it was lower in nursing women at stage II (1.144 +/- 0.110 g/cm2 vs 1.216 +/- 0.095 g/cm2 respectively; p < 0.05). Right femoral neck bone density decreased by 3% between stages I and II in nursing women but did not differ from values in non-nursing women (0.947 +/- 0.110 vs 0.973 +/- 0.108 in stage I and 0.918 +/- 0.114 vs 0.975 +/- 0.098 in stage II respectively; p < 0.05, ANOVA). After weaning, lumbar spine and femoral neck bone density increased by 6% and 8% respectively (p < 0.05, ANOVA). No correlation was found between changes in bone turnover markers or bone density and parity, frequency and duration of nursing episodes, body weight, body mass index, and plasma PRL, E2 and PTH levels. We conclude that in nursing women with a daily calcium intake at the recommended dietary allowance ( > 1200 mg/day), full breastfeeding extending over 6 months is characterized by increased maternal bone turnover and a transient bone loss which normalizes after weaning.

Absorptiometry, Photon↗

PubMed1996

[Immunologic characteristics of undernutrition. I. The undernourished patient in nutritional recovery].

Malnutrition in children is a well known critical factor that determines immunocompetence changes with altered immune response and higher risk to many diseases, especially in developing countries. Moreover, it is related to increased morbi-mortality rates mainly due to infections. For those reasons, 12 undernourished children, age 5 to 24 months were studied along 8 weeks at the Nutritional Recovery Center of Chiquinquira Hospital in Maracaibo, Venezuela. There were 5 cases of kwashiorkor, 5 marasmatics, 1 mixed marasmus/kwashiorkor and 1 case with moderate malnutrition. After a control blood sample was taken and cutaneous tests were done, a nutritional recovery program was began. At regular time intervals and at the end of the study, tests were done again by measuring seric immunoglobulins (IgG, IgA, IgM), secretory IgA (IgAs), C3 and C4 complement, lymphocytic sub-populations, and auto antibodies; cutaneous hipersensitivity tests were also done. As a control group, 10 apparently healthy children of matching age and sex were also studied with the same parameters. Results show that basal seric Igs did not differ significantly from the control group and did not change along the recovery program period, but there was a significant decrease in IgAs at all times of the study. C4 did not change and C3 was lower than control (p < 0.05) but returned to normal value at the end of the recovery period. CD3 and CD4 lymphocytes showed the same pattern. Only two patients showed positive skin tests and auto antibodies were not detected. It is concluded that there is indeed an altered immune competence with low levels of C3, IgAs, and CD3-CD4 lymphocytes that is reversible after nutritional recovery.

Antigens, CD↗

PubMed1995

Clinical trial with Nestorone subdermal contraceptive implants.

The clinical performance and the in vivo release rate of a single 4-cm Nestorone subdermal implant were investigated. Implants manufactured by two different procedures were compared. Volunteers were 70 healthy women of proven fertility. Forty women provided blood samples twice a week in the pretreatment cycle and for 5-6 weeks at 6-month intervals during treatment. Additional control cycles (n = 31) were studied in 19 Copper T users. No pregnancy occurred in 1570 woman-months. Nestorone plasma levels (x +/- S.E.) declined from 112 +/- 8 to 86 +/- 3 pmol/L (Implant A) and from 145 +/- 8 to 57 +/- 5 pmol/L (Implant B) from the first to the 24th month. Progesterone levels were < 9.5 nmol/L in 166 (93%) of 178 blood samplings taken during treatment. Progesterone levels > 16 nmol/L were found in only 7 sampling periods (3.9%) in treated women and in 70 (98.6%) out of 71 control cycles. No ovulation occurred with Nestorone plasma levels above 105 pmol/L. No abnormal changes were observed in plasma lipoproteins or other clinical chemistry parameters during treatment. The implants were well tolerated. The most frequent complaint was the occurrence of irregular bleeding. Enlarged follicles found during pelvic examination in 8 subjects (11.4%) disappeared spontaneously in 10 days to 6 weeks. Implants were removed because of medical (n = 10, 14.3%) or personal reasons (n = 6, 8.6%) or at the 24th month of treatment (n = 54, 77.1%). The estimated average daily in vivo release rate of Nestorone was 45-50 micrograms/day. A single Nestorone subdermal implant affords efficient contraceptive protection during two years.

Adolescent↗

PubMed1995

Breast-feeding duration and growth of fully breast-fed infants in a poor urban Chilean population.

The duration of breast-feeding and the growth of fully breast-fed infants during the first year of life were analyzed according to sex, birth weight, characteristics of the mother, and breast-feeding pattern. All infants (n = 1217) were healthy and fully breast-fed at 30 d postpartum and 63% and 24% were still fully breast-fed at 6 and 12 mo, respectively. The median ages at introduction of nondairy food and of milk supplements were 6.0 and 7.4 mo, respectively. The probability of remaining fully breast-fed for 12 mo was significantly higher in infants with higher birth weight and higher maternal weight, and in infants who breast-fed seven times a day or more in the first 6 mo. The comparison of the monthly weight and length of fully breast-fed infants with the World Health Organization/National Center for Health Statistics reference data showed the adequacy of breastfeeding to support infant growth. When mothers and infants are healthy, breast milk is sufficient to support adequate infant growth and health during the first months of life. The main variables that affect the duration of breast-feeding, nutrition and suckling frequency, are susceptible to interventions by health services. The results reinforce the need to care for maternal nutrition during pregnancy and to provide the support that women need to sustain a high suckling frequency.

Adolescent↗

PubMed1995

Diminished luteinizing hormone biopotency in breastfeeding women.

The effect of nursing on plasma luteinizing hormone bioactivity (B-LH) and immunoactivity (I-LH) was assessed at 4 and 6 months post partum in fully nursing women who experienced their first bleeding between months 5 and 6 post partum (n = 6, short amenorrhoea) or after the month 6 (n = 10, long amenorrhoea). Controls were 10 non-nursing fertile women. Blood samples were drawn twice weekly at month 4 post partum and at month 6 post partum. In the nursing women who were cycling at month 6 and in non-nursing women samples were drawn during the follicular phase. I-LH was measured by a time resolved immunofluorometric assay (DELFIA) and B-LH by the mouse Leydig cell assay. Nursing decreased B-LH more than I-LH resulting in a relationship between B-LH and I-LH different to that of non-nursing women (B-LH = 2.84 x I-LH-0.16 and B-LH = 4.27 x I-LH + 3.11 respectively, P < 0.05, by likelihood test). Plasma B-LH or I-LH were similar in nursing women with short or long amenorrhoea. In conclusion, nursing alters the quality of circulating LH, however, the decreased LH steroidogenic potency does not play a role in determining the duration of lactational amenorrhoea.

Adult↗

PubMed1995

Luteinizing hormone pulsatile release and the length of lactational amenorrhoea.

The pattern of luteinizing hormone (LH) pulsatile release and the mean concentrations of follicle-stimulating hormone, oestradiol and progesterone were studied in nursing and non-nursing women. Blood samples were drawn at 5 min intervals between 10:00 and 14:00 h and between 22:00 and 02:00 h at months 3-4, 5-6, 7-8 and 9-10 postpartum in nursing women and in the follicular phase in non-nursing women. In nursing women, mean LH concentrations at months 3-4 were significantly lower than in non-nursing cycling women only in the subgroup which subsequently experienced > 6 months of lactational amenorrhoea, although all were fully nursing with a similar suckling frequency. LH pulses in plasma were found at all times in nursing women. There were no significant differences in the frequency (about four pulses every 4 h), amplitude or duration of LH pulses related to the duration of amenorrhoea, nor did these parameters vary significantly between amenorrhoeic or cycling nursing women and non-nursing women. Nursing amenorrhoeic women exhibited a normal frequency of LH pulse well in advance of the resumption of the first post-partum menses, suggesting that mechanisms other than the suppression of the gonadotrophin-releasing hormone pulse generator intervened in the inhibition of ovarian function during lactation.

Adult↗

PubMed1995

Risk of diarrheal disease in Ecuadorian day-care centers.

To determine the risk for diarrheal disease (DD) in day-care centers (DCC) for children residing in a poor urban slum area of Quito, Ecuador, compared with that for children from the same environment but cared for in their own residential home (RH), a prospective age-, sex- and locale-controlled study of DD was conducted, including 115 children in DCC and 115 in RH, ages 12 to 42 months. The overall incidence of DD was 46/1000 child weeks. Diarrhea was more common in DCC than in RH (relative risk (RR), 1.75; 95% confidence interval (CI), 1.38 to 2.22; P < 0.001). Poor hygienic practices were more prevalent in DCC than in RH. The use of reused water for child handwashing before eating and for washing raw vegetables was associated with a higher risk of DD in DCC than in RH (RR = 4.08, CI 2.93 to 5.67, P < 0.001; RR = 3.90, CI 2.79 to 5.44, P < 0.001, respectively). These two practices were risk factors in the DCC (RR = 2.74, CI 2.08 to 3.68, P < 0.001; RR = 2.05, CI 1.55 to 2.71, P < 0.001, respectively) when compared with their absence in the same DCC. Shigella (RR = 3.58, CI 1.19 to 10.78, P < 0.02), Aeromonas (RR = 10.47, CI 1.35 to 81.05, P < 0.01), rotavirus (RR = 2.86, CI 1.87 to 4.39, P < 0.001) and Giardia (RR = 1.59, CI 1.00 to 2.59, P < 0.05) were more common in DCC than in RH. More than two-fifths of the Shigella and Aeromonas isolates were resistant to trimethoprim-sulfamethoxazole.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1995

[Electrolytic changes in children with acute lymphoblastic leukemia during remission induction].

The alterations of the water-electrolyte balance are among the commonest early complications of treatment in children with acute lymphoblastic leukaemia (ALL). A study was carried out in thirteen patients with ALL aged between 1.5 and 14 years. Four had high risk ALL and nine had standard risk ALL. All patients received intravenous epirubicin and vincristine, per os prednisone, allopurinol and bicarbonate, and intrathecal methotrexate and hydrocortisone. Venous blood was drawn before starting therapy and on days second and sixth of treatment in order to assay sodium, potassium, calcium, phosphate, magnesium, albumin, urea nitrogen, creatinine and uric acid concentrations. The following alterations were found: hyponatraemia in 4 cases, hypokalemia in 9, hypomagnesaemia in 9, hypocalcaemia in 11, hypophosphataemia in 9, hypouricemia in 3 and hyperuricaemia in 3 others. None of the patients developed acute renal insufficiency. These abnormalities could be due to the leukaemia itself or appear as a consequence of the remission induction treatment.

Adolescent↗

PubMed1995

Neuroendocrine mechanisms of lactational infertility in women.

The current knowledge on the mechanisms of lactational infertility, discussed during a symposium of investigators in this subject, is reviewed. Three periods of lactation are examined: the first weeks postpartum, the period of extended lactational amenorrhea and the recovery of ovarian function. In the first postpartum weeks the inhibition of ovarian function is accounted by diminished pituitary response to GnRH, since exogenous GnRH fails to elicit a LH increase. Suckling can extend the period of ovarian inhibition for weeks, months or years, although it does not fully suppress pulsatile secretion of LH beyond the first weeks. Extended lactational amenorrhea is associated with low LH plasma levels, a great PRL increase in response to suckling, low basal E2 levels and a suppression of estrogen positive feedback. Decreased immunoreactive LH levels may result from partial suppression of the LH pulse generator and a smaller mass of GnRH released in each burst. The role of neurotransmitters, PRL and ovarian factors is discussed. After the recovery of ovulatory cycles suckling still has a residual infertility effect, associated to inadequate luteal function. The sources of variation among women and populations were recognized. Areas in which research is needed to improve the understanding of the mechanisms that sustain lactational amenorrhea are suggested.

Adult↗