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Biomedical subjects

L G Smith

Publications and source records attributed to L G Smith.

At least 19 recordsLinked to original sources
PubMed1992

Postmenopausal uterine bleeding due to estrogen production by gonadotropin-secreting lung tumors.

Two postmenopausal women are described who had uterine bleeding due to hormone production by lung tumors--a large cell carcinoma in one case and a choriocarcinoma in the other. Both tumors stained positively for one or more placental peptides (human chorionic gonadotropin [hCG], placental lactogen, or pregnancy-specific beta-1 glycoprotein) and both patients had extremely elevated serum levels of hCG, suggesting the tumors had some placental-like endocrine function. Clinical and hormonal data supported the concept that the uterine bleeding resulted from estrogen excess due to steroid bio-transformation by the tumors.

Biopsy↗
PubMed1992

Calcium homeostasis in pregnant women receiving long-term magnesium sulfate therapy for preterm labor.

OBJECTIVES: The hypothesis of this study is that calcium homeostasis and bone mineralization are altered in pregnant women receiving long-term therapy with magnesium sulfate as compared with similar women not receiving magnesium sulfate to control preterm labor. STUDY DESIGN: Thirty-nine women between 24 and 32 weeks' gestation, matched for age, race, and duration of bed rest, were enrolled. Indices of calcium homeostasis in serum and urine were measured serially, and bone mineralization of the distal radius was measured at 1 and 11 weeks post partum. RESULTS: Magnesium therapy was administered for a mean duration of 26 +/- 14 days and a cumulative dose of 1405 +/- 963 gm. Serum concentrations of magnesium, phosphorus, and parathyroid hormone increased and those of calcium decreased from baseline values in the magnesium sulfate group and remained uniform throughout the 3-week investigation. The serum magnesium, phosphorus, parathyroid hormone, and calcium concentrations in the control group were unchanged during the study and differed significantly from those in the magnesium sulfate group (p < 0.001). Urinary output of magnesium, calcium, and copper was significantly greater in the magnesium sulfate group than in the control group throughout the study. Urinary losses of calcium in the magnesium sulfate group, approximately 800 to 900 mg/day, were substantial. Although radius bone density 1 week post partum did not differ between groups, the change in bone density from 1 to 11 weeks post partum was significantly lower in the magnesium sulfate group than in controls. CONCLUSIONS: These data suggest that calcium homeostasis is altered during and after long-term magnesium sulfate therapy. The marked, prolonged urinary calcium losses may affect maternal bone mineralization.

Calcification, Physiologic↗
PubMed1992

Oligohydramnios and megacolon in a fetus with vesicorectal fistula and anal-urethral atresia: a case report.

Severe oligohydramnios and extremely dilated bowel filled with hyperechogenic material floating in fluid were the ultrasonographic findings in a fetus at 27 weeks' gestation. Vesicorectal communication and urethral-anal atresia permitted urine to empty into the colon, causing megacolon, oligohydramnios, and markedly increased intraabdominal pressure resulting in pulmonary hypoplasia.

Anal Canal↗
PubMed1992

Indomethacin for the treatment of symptomatic leiomyoma uteri during pregnancy.

Pain secondary to carneous degeneration is the most common complication of leiomyoma uteri during pregnancy. Conventional therapy utilizing bed rest and parenteral narcotic analgesics may often be ineffective. We retrospectively reviewed seven cases of degenerating fibroids complicating pregnancy where the prostaglandin synthetase inhibitor, indomethacin (25 mg orally every 6 hours), was used to treat symptoms of pain. In all cases, relief of symptoms was achieved within 48 hours of initiation of therapy. Two patients required a second course of therapy, and one patient required a third course. Mean duration of therapy was 12 days. One fetus developed transient constriction of the ductus arteriosus and transient oligohydramnios. Two pregnancies aborted, one at 22.9 and one at 22.3 weeks; however, no perinatal complications were directly attributable to indomethacin. The five term deliveries were of healthy normal infants. These retrospective data suggest that indomethacin may be effective in the treatment of pain associated with degenerating uterine leiomyomas in pregnancy.

Adult↗
PubMed1992

A dominant mutation in the maize homeobox gene, Knotted-1, causes its ectopic expression in leaf cells with altered fates.

Dominant mutations of the Knotted-1 (Kn1) homeobox gene of maize alter the differentiation and growth of cells associated with leaf veins. By analyzing Kn1 transcripts and KN1 protein, we show that the gene is not expressed at high levels during the development of wild-type leaves. Instead, Kn1 is expressed in apical meristems of vegetative and floral shoots, and is downregulated as leaves and floral organs are initiated. Kn1 is also expressed in relatively undifferentiated cells within developing vascular bundles, as well as ground tissue, in immature, unelongated axes of wild-type vegetative and floral shoots. In Kn1-N2 mutant plants, quantitative, but not qualitative differences are apparent in Kn1 transcripts and KN1 protein, consistent with previous observations that dominant Kn1 mutations map to non-coding regions of the gene. Kn1 is expressed ectopically in vascular bundles within developing mutant leaves in a pattern that correlates with the phenotypic alterations produced by the Kn1-N2 mutation. Thus, Kn1 apparently alters the fates of leaf cells in which it is ectopically expressed from an early stage of leaf development. Based on these observations, we hypothesize that Kn1 functions in its wild-type context as a regulator of cell determination.

Fluorescent Antibody Technique↗
PubMed1992

Blunt trauma during pregnancy: factors affecting fetal outcome.

During a 9 1/2-year period, 76 pregnant women who sustained blunt trauma were admitted to a level-I trauma center. Fetal outcome was ascertained in 59 patients (78%). Successful delivery was noted in 35 patients (46%). Eight patients (11%) elected to undergo abortion for nonmedical reasons. Sixteen patients (21%) sustained fetal loss, and 17 patients (22%) were lost to follow-up. The 51 patients who either delivered successfully or experienced a fetal loss were studied to determine the factors that affected fetal outcome. Variables analyzed included gestational age and maternal age, Glasgow Coma Scale score, serum bicarbonate level, pH, PCO2, PO2, blood pressure, heart rate, Injury Severity Score, and performance of surgery or diagnostic peritoneal lavage. Logistic regression analysis revealed that ISS (p less than 0.01) and admission serum bicarbonate level (p less than 0.02) have the most significant correlation with fetal outcome. No other variable exhibited a statistically significant influence on fetal outcome. This information documents that fetal demise is related to severity of maternal injury as characterized by ISS. A low serum bicarbonate level corresponds to maternal hypoperfusion and hypoxia, which may be otherwise unrecognized because of the normal physiologic changes occurring during pregnancy. Based on these findings, routine serum bicarbonate determination in all pregnant patients being evaluated for trauma is advocated. Performance of DPL and surgery do not have a significant association with fetal loss and therefore should not be withheld when indicated in a pregnant patient.

Adult↗
PubMed1991

Clonal analysis of hematopoietic stem-cell differentiation in vivo.

Previous work has shown that the 0.02-0.05% of adult mouse bone marrow cells that bear the cell surface phenotype Thy-1loLin-Sca-1+ are enriched 1000- to 2000-fold for hematopoietic stem-cell activity in a variety of assays. When 50-100 cells of this phenotype are injected into an irradiated animal, they can permanently repopulate the entire hematopoietic system. In the present study, limiting-dilution and single-cell experiments were used to address the question of how individual Thy-1loLin-Sca-1+ stem cells contribute to repopulation of the hematopoietic system following irradiation. We calculated that 1 of 13 Thy-1loLin-Sca-1+ cells formed a clone comprising greater than 1% of peripheral white blood cells 3-7 weeks after injection. The majority of these clones included both lymphoid and myeloid lineages. Approximately one-third of the clones continued to produce new blood cells for 9 weeks or more, but the remainder disappeared earlier, including many that were multilineage. Thus, while the majority of Thy-1loLin-Sca-1+ bone marrow cells whose progeny are detected in the in vivo repopulation assay are pluripotential, only a subset undergo long-term self-renewal in vivo. Repopulation appears to be oligoclonal when limiting numbers of Thy-1loLin-Sca-1+ cells are injected. However, the number of clones contributing to hematopoiesis increases in proportion to the number of Thy-1loLin-Sca-1+ cells injected, bringing into question the notion that steady-state hematopoiesis in normal individuals is oligoclonal.

Animals↗
PubMed1991

Trauma during pregnancy. A review of 79 cases.

Few studies provide data on pregnant trauma patients that can be used to direct management decisions. Therefore, this retrospective study of 79 pregnant patients who were injured and admitted to a trauma center during a 9-year period was conducted to obtain such information. Maternal mortality for these pregnant patients was 10%, which was not different from that for nonpregnant females. Overall, rate of fetal loss was 34%. Rates of fetal loss were not different in patients with and without evidence of shock and/or hypoxia or in restrained and unrestrained automobile occupants. Diagnostic peritoneal lavage proved to be 95% accurate and safe. Based on these findings, we concluded the following: pregnancy does not increase maternal mortality from trauma. Blood pressure, pulse rate, and PO2 are unreliable indicators of adequate maternal resuscitation and fetal well-being. Assumption of maternal and fetal stability based solely on these usually standard criteria is unwise. Use of seat belts during pregnancy is advisable in the absence of evidence that restraints increase the rate of fetal loss.

Accidents, Traffic↗
PubMed1991

Porencephalic cyst: a complication of fetal intravascular transfusion.

A case of unilateral porencephalic cyst as a result of intravascular intrauterine transfusion is reported. Although other factors may have contributed, fetal bradycardia and relative hyperviscosity as a result of increased fetal hematocrit value were considered to be related to this event. Because some authors recommend direct intravascular transfusion to supraphysiologic hematocrits to prolong the interval between procedures, we would caution the use of this approach on the basis of theoretic considerations and the occurrence of this complication.

Adult↗
PubMed1991

Spontaneous rupture of liver during pregnancy: current therapy.

Spontaneous hepatic rupture secondary to severe pregnancy-induced hypertension is associated with a high rate of maternal and fetal mortality. Numerous types of surgical management have been described, but a uniform surgical approach has not been accepted. The purpose of this review was to examine modes of surgical therapy reported in the literature since 1976, as well as the 11-year experience at our institution. Twenty-eight cases were extracted from the literature and seven more were identified at our institution. The incidence in our population was one per 45,145 live births. Among 27 cases managed by packing and drainage, an 82% overall survival was achieved, whereas only 25% of eight patients undergoing hepatic lobectomy survived (P = .006). Hepatic hemorrhage with persistent hypotension unresponsive to blood products should be managed by evacuating the hematoma, packing the damaged liver, and draining the operative site. More aggressive surgical techniques, such as hepatic artery ligation or hepatic lobectomy, should be reserved for refractory cases.

Adult↗
PubMed1990

Pulmonary carcinogenesis in rats given implants of shale oil in beeswax pellets.

Pellets of crude shale oil, neutral, basic, or polynuclear aromatic fractions of shale oil, or crude petroleum were implanted in the lungs of rats through a thoracotomy. The pellets had a beeswax-tricaprylin vehicle that allowed the slow release of material into the surrounding parenchyma. A dose-related incidence of lung cancer was observed with each of the materials studies. A greater risk for lung cancer was not demonstrated for crude shale oil compared to crude petroleum.

Animals↗