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Biomedical subjects

P Vasilenko

Publications and source records attributed to P Vasilenko.

16 recordsLinked to original sources
PubMed1992

The effects of nifedipine on pregnancy outcome and morphology of the placenta, uterus, and cervix during late pregnancy in the rat.

OBJECTIVE: Although the calcium antagonist nifedipine has been reported to suppress preterm labor, little is known of the effects of long-term nifedipine use in late pregnancy. In this study the effects of nifedipine on pregnancy outcome and the morphologic features of the reproductive tract in the late-pregnant rat were investigated. STUDY DESIGN: From days 14 to 21 of gestation pregnant rats were administered three or 30 times the maximum human dose of nifedipine reported to suppress preterm labor. Analysis was performed on day 21. RESULTS: Blood vessel dilatation, increased vascularization of the uterus and placenta, and trophoblast hypertrophy were seen in both nifedipine-treated groups. Placental weight was increased in the higher-dose group, but neither dose of nifedipine resulted in any change of fetal survival or malformations. Pup weight was not different from that of controls in the lower-dose group but was significantly reduced (p less than 0.001) with the higher dose. Histologic changes in uterine musculature and cervical collagen were consistent with the inhibitory effects of nifedipine on uterine contractions. CONCLUSION: The results suggest that, in addition to tocolysis, nifedipine can cause vascular dilatation in both the uterus and the placenta. The use of nifedipine within the normal dose range does not appear to adversely affect fetal outcome and may potentially improve fetal outcome in some disorders of pregnancy.

Animals↗
PubMed1992

Comparison of laparoscopic cholecystectomy versus elective open cholecystectomy.

Laparoscopic cholecystectomy has essentially replaced open cholecystectomy as the procedure of choice for gallbladder disease. This rapid shift to laparoscopic cholecystectomy, however, has resulted more from marketing forces than from prospective clinical trials. To evaluate the safety and efficacy of laparoscopic cholecystectomy, the first 486 laparoscopic cholecystectomies at two institutions were studied. These results were then compared to the results of the last 6 months of elective open cholecystectomy cases prior to the introduction of laparoscopic surgery. The age, sex, height, and weight were similar in both groups. The mean operative time was 78.8 +/- 1.8 min for laparoscopic cholecystectomy and 62.7 +/- 2.6 min for open cholecystectomy (p < 0.01). The mean time for tolerating a regular diet was 1.23 +/- 0.04 days in the laparoscopic group versus 2.44 +/- 0.07 days in the open group (p < 0.01). Laparoscopic cholecystectomy patients required only oral pain medications by a mean of 1.22 +/- 0.03 days postoperatively compared to 2.55 +/- 0.07 days postoperatively for those undergoing open cholecystectomy (p < 0.01). The mean length of hospitalization was 1.58 +/- 0.07 days for laparoscopic patients and 3.55 +/- 0.11 days for open patients (p < 0.01). Thirty-one patients undergoing laparoscopic cholecystectomy were converted to open cholecystectomy (6.4%). The most common reasons for conversion to open cholecystectomy were acute inflammation, adhesions, and bleeding. For the laparoscopic patients, the morbidity rate was 8.4% and the mortality rate 0.2% (1 death). In the open cholecystectomy group the morbidity rate was 8.0% and there were no deaths. The most troublesome complication in laparoscopic cholecystectomies continues to be bile leaks and bile duct injuries.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1992

Demonstration of relaxin precursors in pregnant rat ovaries with antisera against bacterially expressed rat prorelaxin.

The existence of rat 18-kilodalton (kDa) prorelaxin, which has been postulated from the coding sequence of cloned cDNA and the results of cell-free translation studies, has been directly demonstrated in rat ovaries with antibodies against bacterially expressed rat prorelaxin. The peptide expressed in E. coli from a rat prorelaxin cDNA construct was comprised of the B- and A-chains of relaxin and a 105-amino acid connecting region. Immunoreactive bands of 18 and 16.5 kDa were shown in ovaries from day 20 pregnant rats. Partial amino acid sequence analysis of both peptides revealed that they had identical N-terminal sequences, corresponding to rat prorelaxin. Both 18- and 16.5-kDa bands were present only from midpregnancy until near term, when they declined sharply. These changes in the concentration of 18-kDa prorelaxin match changes in preprorelaxin mRNA levels, suggesting that relaxin synthesis is regulated at the transcriptional level and not by protein processing. Prorelaxin was transiently secreted by COS-1 cells transfected with preprorelaxin cDNA. Treatment of culture medium with trypsin resulted in the appearance of material corresponding in size to mature relaxin. Thus, correctly folded prorelaxin appears to be a suitable precursor for relaxin. The combined concentrations of 18- and 16.5-kDa peptides in ovaries on day 20 of pregnancy were considerably more than 30 times greater than that of relaxin, however, suggesting that prorelaxin might also be more than a precursor per se.

Amino Acid Sequence↗
PubMed1991

The role of estrogen and relaxin in the reproductive abnormalities of mice with Hertwig's anemia.

Mice homozygous for a mutant allele (an/an) causing a lifelong macrocytic anemia (Hertwig's anemia) also demonstrate an inability to deliver their offspring, despite normal ovulation, conception, implantation, and fetal development. We investigated the roles of estrogen and relaxin in the etiology of the reproductive defect in the Hertwig's anemia mice. Immunoreactive relaxin levels were undetectable in the nonpregnant controls, whereas levels in both timed-pregnant controls and timed-pregnant affected mice were significantly higher than in nonpregnant controls, but not significantly different from each other. Mean interpubic ligament length in the pregnant Hertwig's anemia mice was significantly greater than that in nonpregnant controls, but significantly less than that in the pregnant controls on Day 18 of pregnancy. Porcine relaxin was administered to nonpregnant affected and unaffected littermates and to nonpregnant controls. Whereas controls showed a significant response to porcine relaxin, neither the Hertwig's anemia mice nor their unaffected littermates responded to the porcine relaxin. Additional study was performed to determine estradiol effects in the affected and control animals utilizing detailed computerized morphometric analysis of uterine horns and cervices from immature, estradiol-injected controls and Hertwig's anemia mice. Results demonstrated a statistically significant trophic effect of estradiol upon uterine horn and cervical enlargement, as assessed by weight and volume, in controls. Only a slight, non-significant effect was seen in Hertwig's anemia mice. Additional histological effects of estradiol, including endometrial enfolding observed in controls, were not present in Hertwig's anemia mice. Lack of response to both estrogen and relaxin is responsible for the parturitional defect in Hertwig's anemia mice.

Anemia, Macrocytic↗
PubMed1991

The use of bupivacaine in elective inguinal herniorrhaphy as a fast and safe technique for relief of postoperative pain.

The intraoperative use of local anesthetic agents to decrease postoperative pain has been used in many types of procedures. Most of these techniques involve needle injection of anesthetic and result in a low but troublesome incidence of complications. In this study, we evaluated the reliability, safety, and efficacy of a technique emphasizing bathing of tissues with anesthetic rather than needle injection for relieving postoperative pain. Thirty consecutive patients undergoing outpatient elective inguinal herniorrhaphy with general anesthetic were prospectively randomized into four treatment groups. Group 1 received 0.5 per cent bupivacaine plus epinephrine 1 to 200,000; group 2, 0.5 per cent bupivacaine; group 3, normal saline solution, and group 4, no treatment. At the end of the repair, one-third of the test solution (approximately 5 milliliters) was bathed along the spermatic cord throughout its length in the inguinal canal. The external oblique aponeurosis was closed superficial to the cord structures and another one-third of the solution was instilled into the wound. Just prior to the end of skin closure the remaining solution was instilled subcutaneously. No needles were used to instill the solutions and they were not suctioned or removed from the wound. Data collection consisted of an analog type of patient questionnaire allowing subjective assessment of postoperative pain at various time intervals during the first 20 hours postoperatively. Pain medication provided was propoxyphene, 100 milligrams and acetaminophen, 650 milligrams every three hours as needed. Total doses of pain medication for the study period and the time to first pain medication requirement were obtained. Results were analyzed using analysis of variance, and Wilcoxon ranked sums test. Patients in group 1 (0.5 per cent bupivacaine with epinephrine) exhibited significantly less pain than those in groups 3 (saline solution) and 4 (control) for more than 12 hours postoperatively. Patients in group 2 (0.5 per cent bupivacaine) likewise experienced less pain than those in groups 3 and 4 through seven hours. The patients receiving saline solution were not significantly different than those in the control group throughout. Objectively, groups 1 and 2 required fewer total doses of pain medication and waited longer before requesting oral pain medication postoperatively compared with those in the control group. No complications occurred that could be attributed to the technique. The results of this study indicate that the bathing of wounds with 0.5 per cent bupivacaine with or without epinephrine 1:200,000 is a safe and effective method of decreasing postoperative pain for several hours in patients undergoing elective inguinal herniorrhaphy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Laparoscopic tubal sterilization. The potential for thermal bowel injury.

One of the most severe complications of laparoscopic tubal sterilization is bowel burns, although they often go undetected at the time of laparoscopy. Controversy remains over whether these injuries are caused directly by operator error or indirectly from a hot oviduct's or instrument's inadvertently touching and burning the intestine. A study was performed to determine the potential for direct or indirect bowel burns using bipolar electrocoagulation in rabbits. The results indicate that neither a hot tube nor hot (recently used) forceps could cause injuries to the serosal surface of the intestine. That was true both of immediate injury and after one to five days of recovery. It was observed that the hot uterine tube caused significant bowel adhesions by five days after the procedure. Direct electrocoagulation of the bowel using 40 W for three seconds caused a minor, noticeable blanch on the bowel that was not detectable with gross or histologic means after one day of recovery. A direct bowel injury did result when 80 W was used for three seconds; the bowel became perforated after one day. These findings indicate that it is unlikely that one can produce a bowel burn indirectly from a hot uterine tube or instrument and that only a direct insult to the bowel appears to cause an injury. However, adhesions could be a complication of the procedure and should be considered.

Animals↗
PubMed1988

Weight gain during adolescent pregnancy. Associated maternal characteristics and effects on birth weight.

Prospective data from 696 adolescents who delivered at 37 weeks or more gestation were analyzed to determine factors associated with weight gain during pregnancy and effects of pregnancy gains on birth weight and other outcomes of pregnancy. Pregnancy weight gain was found to be associated with the following factors: mother's ethnicity, length of gestation, parity, and presence of pregnancy-related hypertension. Maternal weight gain during pregnancy markedly increased infant birth weight. The risk of a low birth-rate infant was greatly reduced (OR = 0.14; CL = 0.1-0.2), and the risk of a macrosomic infant was 13.1 times higher (OR = 13.1; CL = 8.9-19.2) in adolescents gaining 20 kg or more. There was no increased risk for Caesarean section, fetal/neonatal death, or neonatal intensive care unit admission based on maternal weight gain. No effect of prepregnant relative weight on maternal weight gain was detected. The effect of weight gain on birth weight was also independent of the maternal prepregnant relative weight.

Adolescent↗
PubMed1988

Eight weeks of streptozotocin-induced diabetes influences the effects of cold stress on immunoreactive beta-endorphin levels in female rats.

Cold stress produced a significant reduction in the concentration of immunoreactive beta-endorphin (IR-BE) in the anterior pituitary of diabetic female rats. IR-BE levels in the anterior pituitary of non-diabetic female rats were not affected by exposure to the cold. The effects of cold stress on IR-BE levels in the neurointermediate lobe of the pituitary and the hypothalamus were attenuated in diabetic as compared to control animals. These data suggest that in female rats, eight weeks of diabetes produced alterations in the neuroendocrine mechanisms which modulate IR-BE levels in the pituitary and hypothalamus in response to cold stress.

Animals↗
PubMed1988

Influence of young maternal age and parity on term and preterm low birthweight.

Data on 4496 singleton births to young women (19 years or less) are reported by maternal age and parity with birthweight and gestation cross-classified to yield rates of preterm and term low birthweight. After adjustment, the risk of preterm low birthweight was increased with very young maternity (15 years or less); preterm low birthweight and term low birthweight were each increased with young multiparity. These data suggest that the identification of factors associated with preterm birth and their incorporation into the prenatal care regimen may be important in improving pregnancy outcome in young women.

Adolescent↗
PubMed1988

A new and simple method of measuring menstrual blood loss.

Although it is difficult for women to make reliable judgments about their menstrual blood loss, the direct measurement of such blood loss is useful in diagnosis and in evaluation of therapy. We developed a new and simple procedure for measuring blood on sanitary materials. The procedure is a modification of previous alkaline hematin methods but overcomes some of their major drawbacks. The method involves the separate extraction of blood using a detergent solution and color development of sample aliquots with sodium carbonate. The standard curves obtained for four products tested--regular maxi pads, thin maxi pads and two brands of tampons--were significantly linear over the range of 1-10 mL of blood. The extraction efficiency varied with the four products; tampons exhibited the highest extraction efficiency and thin maxi pads the lowest. Blood loss in normally menstruating women was estimated to be 41.8 +/- 3.9 mL, which correlates well with other estimates reported. Furthermore, the procedure can be used to measure both very low and very concentrated levels of blood on pads or tampons and thus can be used to assess both functional and dysfunctional uterine bleeding.

Female↗
PubMed1987

Growth-promoting effects of relaxin and related compositional changes in the uterus, cervix, and vagina of the rat.

Although the precise role of relaxin has yet to be elucidated, it has been implicated in the regulation of physiological and biochemical processes in the reproductive tract during pregnancy and parturition. In this study, the growth-promoting effects of relaxin and related compositional changes in the uterus, cervix, and vagina of immature ovariectomized estrogen-primed rats were examined. Relaxin increased the wet weight of the uterus, cervix, and vagina in a significant and linear manner over the log of the dose range (1-30 micrograms; 6 h). The increase in uterine weight was due to increases in both dry weight and water content at all doses. A dose of 1 microgram relaxin induced maximal increases in dry weights in the cervix and vagina over control values; higher doses increased wet weight, but these changes were due solely to increases in water content. Thirty micrograms of relaxin were found to increase total soluble protein and glycogen content of the vagina above control values after 6 h. Relaxin did not alter the total collagen levels of the uterus or cervix, and collagen concentrations were significantly reduced in these organs 6 and 24 h after treatment. Total glycosaminoglycan levels were elevated by relaxin in the uterus (6 h) and cervix (24 h). Total vaginal collagen was increased 24 h after relaxin injection, but the collagen concentration was decreased over the time interval studied, and glycosaminoglycan levels in the vagina were unaltered. In summary, relaxin stimulates growth of the uterus, cervix, and vagina by increasing water content and tissue mass. The increases in distensibility that relaxin induces in these organs appear to be related to changes in the fluid matrix and proteoglycan metabolism rather than alterations in collagen concentration, at least 6-24 h after a single injection. These results support the hypothesis that relaxin plays a significant role in the maintenance of pregnancy through its contribution to fetal accommodation and in the facilitation of parturition through expansion of the entire birth canal.

Animals↗
PubMed1986

Uterine growth-promoting effects of relaxin: a morphometric and histological analysis.

The hormone relaxin has been implicated in the regulation of several processes in the reproductive tract during pregnancy and parturition. This study investigated the uterine effects of relaxin in immature and mature ovariectomized, estrogen-primed rats using morphometric and histochemical analysis. Rats were sprayed at 30 or 70 days of age and given estrogen (5 micrograms) 7 days later. After a week, they received an injection of porcine relaxin (100 micrograms) and were killed 6 h later; controls received vehicle alone. Histological sections were obtained from 7 levels of each uterine horn, and the volumes of endometrium and myometrium were calculated by use of a Zeiss Videoplan Computer Image Analyzer. In immature animals, relaxin treatment doubled uterine weights during the treatment period, and cross sections from relaxin-treated animals exhibited significant increases in the areas of both the myometrium and endometrium, 150% and 130% respectively. Mature animals were less responsive to relaxin although they also exhibited significant increases in uterine weight (31%), myometrial volume (29%), and endometrial volume (22%). With the use of Masson's Trichrome stain for collagen, we observed that relaxin alters the connective tissue framework of both endometrium and myometrium; control uterine collagen appears highly organized and dense with compact collagen fibers, whereas the collagen of relaxin-treated uteri is loosely arranged and disorganized with widely separated collagen fibers. Relaxin-stimulated uteri exhibited significantly greater vascularization, as evidenced by the size of arteries and veins in the vascular region between the circular and longitudinal muscle layers. Increased vascularization and uterine blood flow may be one mechanism involved in relaxin's uterotropic effect and is being investigated further.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Streptozocin diabetes alters immunoreactive beta-endorphin levels and pain perception after 8 wk in female rats.

Plasma, pituitary, and hypothalamic levels of the endogenous opioid peptide beta-endorphin were measured by radioimmunoassay and column chromatography in female rats 8 wk after the induction of diabetes with streptozocin (STZ) and in control female rats. In addition, pain perception was determined by measuring the latency to paw lick or jump after being placed on a hot plate. Plasma levels of immunoreactive beta-endorphin (IR-BE) were significantly reduced in STZ-induced diabetic female rats, as were the content and concentration of IR-BE in the neurointermediate lobe of the pituitary (NIL) and the content of IR-BE in the hypothalamus. The concentration but not the content of IR-BE in the anterior pituitary (AP) of the STZ-induced diabetic rats was increased significantly. Streptozocin-induced diabetes also resulted in a significant reduction in the total protein content of the AP, NIL, and hypothalamus. Column chromatography indicated that the decrease in IR-BE in the plasma, NIL, and hypothalamus represented a decrease in beta-endorphin, whereas the increase in IR-BE in the AP represented an increase in both beta-endorphin and beta-lipotropin. Diabetic animals consistently showed decreased latencies to paw lick or jump when subjected to hot-plate testing after 7 wk. These findings suggest that in female rats, central and peripheral endogenous opiate levels and tolerance to nociceptive thermal stimulation were diminished by 8 wk of chemically induced diabetes.

Animals↗
PubMed1985

Diabetes induced by streptozocin results in a decrease in immunoreactive beta-endorphin levels in the pituitary and hypothalamus of female rats.

Immunoreactive beta-endorphin (IR-BE) was measured by radioimmunoassay in the anterior pituitary (AP), neurointermediate lobe of the pituitary (NIL), and hypothalamus of female rats 4 wk after being made diabetic by a single injection of streptozocin (STZ). STZ-induced diabetes resulted in a significant reduction in the content and concentration of IR-BE in the AP and the content of IR-BE in the hypothalamus. Total hypothalamic protein was also significantly diminished. IR-BE levels in the NIL were unchanged. Column chromatography indicated that the reduction in IR-BE in the AP of the diabetic female rats represented a decrease in peptides that co-eluted with beta-endorphin and beta-lipotropin. In the hypothalamus, the reduction in IR-BE was represented solely by a decrease in a peptide co-eluting with beta-endorphin. Beta-lipotropin was not detectable in the hypothalami of control or diabetic female rats. These results suggest that, in the rat, diabetes may produce alterations in the mechanism(s) that regulate endogenous opiate levels in the pituitary and hypothalamus.

Animals↗
PubMedDate not supplied

Effects of early maturation on fetal growth.

While the association of young maternal age with low birthweight (LBW) is well known, the contribution of early menarche to this association has never been studied. We examined the effects of early menarche (less than or equal to 11 years) on LBW and its two major underlying causes: pre-term delivery and smallness-for-gestational-age (SGA). Results represent a narrow chronological age range, 17-18 years, of a larger geographically based cohort of 2789 pregnant adolescents. Adjusted odds ratios (AOR) indicated that early menarche was significantly associated with an increased risk of LBW which was specific to SGA. The attributable risk of SGA with early menarche exceeded 20%. Early age at menarche is also correlated with an earlier onset of sexual activity, pregnancy, and childbearing. Consequently, adolescents with early menarche are over-represented in a sample limited to young gravidae or a sample that contains a stratum of young gravidae. This may have previously obscured the effects or early menarche on foetal growth and attributed them to a more frequently measured characteristic, young maternal age. Thus, effects of secular change in age at menarche may not be wholly benign. Improvements in maternal fertility and nutritional status appear to be offset by intrauterine growth retardation in the offspring.

Adolescent↗