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Biomedical subjects

S Segal

Publications and source records attributed to S Segal.

At least 163 records · Page 9Linked to original sources

Pneumomediastinum in labor.

We describe pneumomediastinum in a primigravida with delay in the second stage of labor. The pathophysiology, clinical presentation, and management are reviewed.

Adult↗

Incidence and contribution of predisposing factors to transverse lie presentation.

OBJECTIVES: Reassessment of predisposing factors to transverse lie presentation. METHODS: Retrospective analysis of delivery data on 92 women with transverse lie presentation, using ultrasonography, and 92 randomly chosen control vertex deliveries. RESULTS: The association between transverse lie and multiparity, prematurity, placenta previa, polyhydramnios and uterine anomalies is reaffirmed. Predisposing factors were found in 66% of primiparas but in only 33% of multiparas. CONCLUSIONS: Known predisposing factors to transverse lie presentation withstood a closer and more accurate assessment of their incidence.

Adult↗

Hypertension in pregnancy: hemodynamics and diurnal arterial pressure profile.

OBJECTIVE: To characterize the 24-h arterial pressure (AP) profile and the left ventricular (LV) structures and functions in women with pregnancy-associated hypertension. METHODS: Twenty nulliparous pregnant women after 20 weeks' gestation, 10 normotensive and 10 hypertensive women matched for gestational age, were hemodynamically investigated using 24-h AP monitoring and Doppler echocardiography to determine LV structures and functions, both systolic and diastolic. RESULTS: The hypertensive women had significantly higher AP determinations throughout the 24 h, with no change in diurnal variation, i.e. nocturnal decline and early morning peaks. Their LV mass was greater and it was accompanied by a slight reduction in contractility and a significant reduction in LV relaxation. The increased AP was due to peripheral vasoconstriction, while cardiac output was preserved. CONCLUSIONS: It appears that pregnancy-associated hypertension is caused mainly by arterial vasoconstriction and not by higher cardiac output. The hypertension increases the LV mass, which is associated with a fall in LV relaxation.

Adult↗

Renal brush border membrane lipid composition in Basenji dogs with spontaneous idiopathic Fanconi syndrome.

To comprehend the renal defect underlying idiopathic Fanconi syndrome in the Basenji dog, we have focused on delineating the lipid profiles of renal brush border membranes isolated from affected and normal Basenji dogs to establish any physical or compositional changes underlying previously observed transport and membrane-fluidity changes. The lipid composition was studied with respect to total lipid, cholesterol, and phospholipid content, cholesterol to phospholipid ratio, distribution of the major phospholipid classes, and fatty acid composition. Total phospholipid of the isolated renal brush border membranes from Fanconi syndrome dogs analyzed by 31P nuclear magnetic resonance showed no difference compared with that of normal dogs. Examination of total fatty acids in both membranes using gas-liquid chromatography analysis of fatty acid methyl esters showed no difference in the mole percents of the major fatty acids. Our data suggest that changes in bulk membrane fluidity of the Fanconi syndrome dog renal brush border as measured by 1,6-diphenyl-1,3,5-hexatriene cannot be attributed to phospholipid and fatty acid compositional change. In the membranes isolated from affected dog kidney, the cholesterol content determined by gas-liquid chromatography analysis was 66 mol% higher than in membranes isolated from normal dog kidney. This correlates with the higher cholesterol to phospholipid molar ratio of 0.82 +/- 0.08 in the affected animal as compared with 0.58 +/- 0.04 in the normal. Cholesterol content and its microdomain in the membrane bilayer may be important in modulating transport functions. Increased membrane cholesterol content may affect the conformational motility of membrane transport proteins and thus affect their function.

Animals↗

Reversal of the measles virus-mediated increase of phosphorylating activity in persistently infected mouse neuroblastoma cells by anti-measles virus antibodies.

To investigate the effect of persistent measles virus infection on signal transduction in cells of neuronal origin, the mouse neuroblastoma cell line NS20Y/MS, which is persistently infected with measles virus, was used. The results demonstrate an approximate 50% increase in total phosphorylation and a similar increase in protein kinase C (PKC) activity. Western blot analysis with anti-total PKC or anti-PKC-alpha antibodies revealed a significant increase in the level of an 80K immunoreactive PKC in NS20Y/MS cells. Following incubation of NS20Y/MS cells with polyclonal anti-measles virus antibodies, which down-regulate the level of measles virus proteins, total and PKC-mediated phosphorylation returned to the basal level of uninfected cells. This effect was reversible and removal of the antibodies resulted in restoration of the high level of total and PKC-mediated phosphorylation. The release of infectious measles virus was strongly inhibited by incubation of NS20Y/MS cells with the PKC inhibitor, 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine (H-7). These results demonstrate that measles virus induces elevation in cellular phosphorylation which is essential for measles virus production.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

Identification of a thymidylate synthase ribonucleoprotein complex in human colon cancer cells.

Translation of thymidylate synthase (TS) mRNA is controlled by its own protein product, TS, in an autoregulatory manner. Direct binding of TS protein to two different cis-acting elements on the TS mRNA is associated with this translational regulation. In this study, an immunoprecipitation-reverse transcription-PCR technique was used to identify a TS ribonucleoprotein (RNP) complex in cultured human colon cancer cells. Using antibodies specific for TS protein, we show that TS is complexed in vivo with its own TS RNA. Furthermore, evidence demonstrating a direct interaction between the mRNA of the nuclear oncogene c-myc and TS protein is presented.

Base Sequence↗

Uridine diphosphate hexoses in leukocytes and fibroblasts of classic galactosemics and patients with other metabolic diseases.

To examine uridine diphosphate hexose (UDPhexose) content of cells that have more complete metabolic patterns than erythrocytes, which have been commonly used in the study of galactosemia, the concentrations of uridine diphosphate galactose (UDPgalactose) and uridine diphosphate glucose (UDPglucose) were determined in white blood cells (WBC) and fibroblasts cultured from skin biopsies. Leukocyte UDPgalactose and UDPglucose values were determined in 60 normal individuals, 14 classic galactosemics, and 18 patients with other metabolic diseases on protein-restricted and low-lactose diets. There was no difference in the average concentration of these compounds between any of these groups. There was no relationship between age and WBC UDPhexose content or correlation of WBC and erythrocyte UDPhexose levels in the same blood specimens. WBC from galactosemic individuals differ from their red blood cells because the former do not show the low average UDPgalactose levels and abnormal UDPglucose to UDPgalactose ratio previously reported for erythrocytes from galactose-1-phosphate uridyltransferase-deficient individuals. Fibroblast cell lines from 10 normal and 10 galactosemic individuals, cultured and grown to confluence in glucose medium, also showed no difference in nucleotide sugar concentrations. Thus far, of the cell types easily available, red blood cells appear to be unique in showing an abnormality in nucleotide sugar metabolism. The fact that galactosemic fibroblasts demonstrate no abnormality in the concentration of these compounds suggests that the defective galactosylation that has been observed in galactosemic fibroblasts is not due to unavailability of UDPgalactose.

Adolescent↗

Treatment of pelvic abscesses and other fluid collections: efficacy of transvaginal sonographically guided aspiration and drainage.

OBJECTIVE: The purpose of this study was to evaluate the clinical efficacy of transvaginal sonographically guided aspiration and drainage of pelvic fluid collections. MATERIALS AND METHODS: Forty patients underwent transvaginal sonographically guided aspiration of a possible pelvic abscess (41 pelvic collections). In patients with clinical findings highly suggestive of infection, both purulent and nonpurulent collections were immediately drained via a catheter. In patients with clinical findings moderately suggestive of infection, nonpurulent collections were completely removed by aspiration and the aspirates were cultured; however, purulent collections were immediately drained via a catheter. RESULTS: All collections were successfully accessed by transvaginal sonography. For 27 of the 41 collections, the aspirate was purulent (18 collections) or the patient's clinical findings were highly suggestive of infection (nine collections) and catheter drainage was performed. Seventeen of the 27 collections completely resolved and surgery was not required. Four of the 27 collections were in patients who had surgery for reasons other than persistent infected collection. For six of the 27 collections, catheter treatment was not successful and surgery was required. The overall success rate of catheter drainage was 78%. In the remaining 14 of the 41 collections, the aspirate was serous or serosanguineous, and the patient's clinical findings were moderately suggestive of infection. Cultures of aspirates of seven collections were positive for microorganisms. Eleven collections were successfully treated with antibiotics or no therapy was required (based on culture results); for three, surgery was required. Two complications occurred: one vaginal fistula after catheter drainage and one disruption of vaginal sutures after aspiration. CONCLUSION: Transvaginal sonographically guided drainage is effective treatment of pelvic abscess, being either completely curative or temporizing in 78% of patients. Catheter treatment was unsuccessful and surgery was necessary in 22% of patients. For nonpurulent collections, catheter drainage is indicated only when clinical findings are highly suggestive of infection.

Abscess↗

The expression of HLA class I antigen in prostate cancer in relation to tumor differentiation and patient survival.

The expression of HLA class I antigens was studied using the immunoperoxidase technique on 30 patients with prostate cancer and 29 patients with benign prostatic hypertrophy (BPH). Forty-three percent of the tumors stained positive, in contrast to 21% of the BPH. An inverse relationship was noted between class I expression and degree of tumor differentiation: 88% of the well-differentiated tumors (8/9) expressed class I antigen, compared with 33% (3/9) of the moderately differentiated and 16% (2/12) of the poorly differentiated tumors. No significant survival difference was found between those with class I-positive and -negative tumors. However, when both class I expression and degree of differentiation were considered, those with positive tumors at each level of differentiation had better survival than those with negative tumors. These data suggest that HLA class I expression may serve as a finite prognostic factor and may have relevance in future immunotherapy.

Adenocarcinoma↗

Regulation of murine Max (Myn) parallels the regulation of c-Myc in differentiating murine erythroleukemia cells.

Max is a basic region-helix-loop-helix-leucine zipper protein that consists of two major isoforms, p22 (long form, Max-L) and p21 (short form, Max-S). These proteins are encoded by two [the 1.9- and the predominant 2.3-kilobase (kb) forms] of the five alternatively spliced max mRNA species. We now demonstrate that N,N'-hexamethylene bisacetamide-mediated differentiation of murine erythroleukemia cells leads to a pattern of biphasic down-regulation of the 1.9- and the 2.3-kb myn (murine max) mRNAs that closely parallels that which occurs for myc mRNA. In contrast, the p22/Myn-L and p21/Myn-S protein isoforms down-regulate in monophasic fashion. Unlike the short-lived myc mRNA, the myn message is quite stable. However, its half-life of 3-6 h is still consistent with the biphasic down-regulation that accompanies differentiation. Furthermore, unlike myc, the overexpression of which prevents differentiation, elevated max levels merely delay differentiation. Coincident with this is a delay in the second decline of c-myc mRNA. In N,N'-hexamethylene bisacetamide-induced cells blocked from differentiating by overexpression of c-, N- or L-myc, myn mRNA expression is constitutive. These findings suggest that myn may also be involved in differentiation.

Animals↗

31P NMR spectra of intact red blood cells: quantitation of UDPGlucose and UDPGalactose.

The combined levels of uridine diphosphogalactose (UDPGal) and uridine diphosphoglucose (UDPGlu) were measured directly by 31P NMR spectroscopy in intact fully oxygenated erythrocytes. Quantitative analysis was obtained using a sealed capillary of methylene diphosphonate (MDP) calibrated with standard solutions of UDPGlu and UDPGal of known concentration prepared in KRB/BSA. The combined peaks of UDPGlu and UDPGal were integrated after subtraction of the underlying broad component originating from membrane phospholipids. The average concentration of 27.16 +/- 5.18 nmole/ml or 8.08 +/- 1.36 mumole/100 g hemoglobin obtained for these metabolites correlated well with their total determined by HPLC of trichloracetic acid (TCA) extracts of the same samples.

Adult↗

The effect of dietary fruits and vegetables on urinary galactitol excretion in galactose-1-phosphate uridyltransferase deficiency.

Even on a lactose-restricted diet, urinary galactitol excretion and erythrocyte galactose-1-phosphate levels are persistently elevated in patients with galactose-1-phosphate uridyltransferase deficiency. In order to determine the contribution of galactose in dietary fruits and vegetables to this phenomenon, (1) the content of galactose in a lactose-free diet was directly measured when a galactosaemic patient's diet was specifically enriched in those fruits and vegetables which contain relatively large amounts of free galactose and (2) galactitol excretion was determined during ingestion of this diet for 3 weeks and while on a synthetic diet for 1 week that provided < 8 mg galactose/day. For comparison the effect of a 3-week supplementation of 200 mg galactose/day was determined. The measured intake in total foodstuffs matched the theoretical content of galactose in the patient's diet based on amounts in fruits and vegetables alone, thus supporting the concept that fruits and vegetables are primarily responsible for galactose intake in a lactose-free diet. All of the dietary manipulations, however, had relatively little effect on metabolite levels, suggesting that endogenous galactose production is primarily responsible for the elevated levels of galactose metabolites routinely detected in patients on lactose-restricted diets.

Adolescent↗

Neglected transverse lie with uterine rupture.

We present a case of neglected transverse lie with uterine rupture, which is rarely encountered in modern obstetric practice. The prominent clinical features, including uterine rupture and fetal death, are described. Treatment entails resuscitative measures and Cesarean delivery.

Adult↗

The effect of H-ras expression on tumorigenicity and immunogenicity of Balb/c 3T3 fibroblasts.

In an attempt to define immunological parameters affected by the H-ras oncogene, we have used Balb/c 3T3 cells transfected with either H-ras (98/6), H-ras+v-myc (98/4v) or plasmid only (98/1). We found that while control and oncogene-transfected Balb/c 3T3 cells exhibit similar low sensitivity to lysis by natural killer (NK) cells, H-ras+v-myc-transfected cells could immunize syngeneic Balb/c mice and induce cytotoxic T cells (CTL) with broad specificity, that lysed all types of Balb/c 3T3 cells tested. Immunization of Balb/c mice with 98/4v cells prevented homologous tumor formation and partially inhibited the formation of tumors derived from H-ras-transfected cells. 98/6 cells were not immunogenic in vivo and did not protect the animals from a challenge of 98/6 cells. The results suggested that CTLs but not NK effector cells were important for eliciting in vivo tumor rejection of H-ras+v-myc-transfected cells. In contrast, antigens eliciting the cytotoxic T-cell response, and possibly also the in vivo tumor cell rejection response, were expressed on all cell types tested but were immunogenic only on the surface of 98/4v cells. We further determined major histocompatibility complex (MHC) class-I molecule expression on the outer cell surface and found that H-2K was down-regulated in H-ras-transfected cells. The results support the observation that oncogenes can down-regulate specific MHC antigens, thereby preventing presentation of tumor antigens and allowing tumor escape from immune recognition.

3T3 Cells↗

Different regulatory levels are involved in the generation of hemopoietic cytokines (CSFs and IL-6) in fibroblasts stimulated by inflammatory products.

In this present study we have characterized the array of hemopoietic cytokines generated by fibroblasts in response to inflammatory signals. It was shown that murine embryo fibroblasts (MEF) are able to generate colony stimulating factors (CSFs) [granulocyte-macrophage (GM-CSF), macrophage-CSF (CSF-1) and granulocyte-CSF (G-CSF)] as well as the hemopoietin interleukin 6 (IL-6), while the production of IL-3, IL-4 or tumor necrosis factor (TNF) could not be detected in MEF, as assessed by bioassays or expression of specific mRNA. The production of colony promoting activity was observed when fibroblasts were stimulated by lipopolysaccharide (LPS) or individual cytokines [IL-1, interferon-gamma (IFN-gamma), IL-2, IL-4 or TNF] in serum-free conditions as well as by serum itself. These inducers differentially stimulated in MEF the production of various CSFs; LPS induced mainly CSF-1, while cytokines or serum induced equivalent amounts of GM-CSF and CSF-1. The production of IL-6 was induced by LPS in serum-free conditions, while stimulation by cytokines (IL-1 or IFN-gamma) resulted in IL-6 production only in serum-supplemented cultures. Serum by itself did not induce IL-6 production by MEF. The secretion of IL-6 by fibroblasts was detected early and peaked after 6 hours, while CSF activity peaked after 24-72 hours, depending on the inducer. Constitutive mRNA expression of CSF-1 was detected in serum-free conditions in unstimulated MEF, however colony-promoting activity was detected only upon stimulation with cytokines, LPS or serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗