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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↗
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↗
PubMed1978

A possible new approach to the management of brain abscesses.

A report is given of effective non-surgical treatment with antibiotics in a patient with a large brain abscess.Non-surgical treatment of brain abscesses may be possible if massive doses of specific bactericidal antibiotics are used and the patients are followed up with frequent brain scans and computerized tomography.

Adult↗
PubMed1978

Pulmonary carcinogenesis in rats given implants of cigarette smoke condensate in beeswax pellets.

Lungs of inbred OM/NCR and outbred Sprague-Dawley rats were given implants, through a thoracotomy, of pellets of cigarette smoke condensate (CSC) suspended in a beeswax-tricaprylin vehicle. The pellets slowly released material into the surrounding parenchyma, which resulted in a dose-related increased incidence of lung cancer, predominantly invasive and metastasizing epidermoid carcinoma. A 42% prevalence of pulmonary carcinoma was present in the highest dosage group, which received 67 mg CSC, exposing approximately 1.65 cm2 bronchiolar epithelium. Squamous metaplasia associated with the implanted site preceded the appearance of the carcinomas and was more severe, with the larger pellets having more concentrated CSC. No difference was observed in incidence of pulmonary carcinomas with the use of CSC containing high or low concentrations of nicotine. The potential value of this bioassay system were discussed.

Animals↗
PubMed1977

Vegetative bacterial endocarditis on the prolapsing mitral valve. Echocardiographic evaluation.

Vegetative endocarditis on the prolapsing mitral valve can be diagnosed with an echocardiogram and the response to therapy can be followed with this technique. A dense mass of fuzzy echoes was noted on the prolapsing posterior leaflet of an echocardiogram from a patient with endocarditis. Three months after the initiation of antibiotic therapy, the mass of echoes had disappeared and was replaced by a dense linear echo, suggesting fibrosis of the part of the mitral valve that had been infected previously. Persistence of the echocardiographic evidence of endocarditis, despite negative blood cultures, may indicate persistence of the risk of peripheral embolization.

Echocardiography↗
PubMed1976

Serratia marcescens and the urologist.

Serratia marcescens, long considered a non-pathogen, is now found to be responsible for outbreaks of nosocomial infections. An outbreak of Serratia infection at 2 institutions is reported, in which 253 cultures of Serratia were grown and 115 patients were involved. The 3 most important conditions that preceded isolation of Serratia were the use of indwelling urethral catheters, antibiotic therapy and operation. All infections were acquired in the hospital. An epidemiological survey showed that the organism is present in the environment, even in the absence of active infection.

Aged↗