PubMed Health⌕ Search

Biomedical subjects

S Rottem

Publications and source records attributed to S Rottem.

At least 55 records · Page 3Linked to original sources
PubMed1992

Mycoplasma fermentans (incognitus strain) induces TNF alpha and IL-1 production by human monocytes and murine macrophages.

We have demonstrated that Mycoplasma fermentans (incognitus strain), as well as M. fermentans KL4, PG 18 and IM 1 strains have the ability to activate human peripheral blood monocytes and murine macrophages of two inbred strains to secrete a high level of tumor necrosis factor alpha (TNF alpha) in a dose-dependent manner. Secretion of interleukin-1 (IL-1) was also stimulated following the incubation of human monocytes with the organism. We suggest that cytokine secretion following infection with M. fermentans (incognitus strain) that was detected in AIDS patients may contribute to the pathological manifestations, including cachexia, in this disease.

Animals↗
PubMed1992

Fusion-mediated transfer of plasmids into Spiroplasma floricola cells.

We have developed and characterized a system for the transfer of plasmids encapsulated in large unilamellar vesicles (LUV) into Spiroplasma floricola BNR1 cells. The approach is based on the ability of S. floricola-derived LUV to fuse with S. floricola cells. The fusion was continuously monitored by an assay for lipid mixing based on the dequenching of the fluorescent probe octadecylrhodamine B (R18) that was incorporated into LUV at self-quenching concentrations. The fusion was also evaluated by fluorescence-activated cell sorter measurements and by sucrose density gradient analysis. LUV-cell fusion occurred only in the presence of low concentrations (5%) of polyethylene glycol (polyethylene glycol 8000) and depended on temperature, the LUV/cell ratio, and divalent cations in the incubation medium. Throughout the fusion process, spiroplasma cells remained intact and viable. Under optimal fusion conditions, the plasmid pACYC, encapsulated in LUV by reversed-phase evaporation, was transferred into live S. floricola cells and expressed chloramphenicol acetyltransferase activity. The expression was transient with maximal chloramphenicol acetyltransferase activity observed after 6 h of incubation of the transfected cells.

Chloramphenicol O-Acetyltransferase↗
PubMed1992

Differentiating malignant from benign ovarian tumors with transvaginal color flow imaging.

The impedance to blood flow was examined by transvaginal color flow imaging in 53 ovarian masses before exploratory laparotomy. Serum CA 125 levels were measured in all subjects. Thirty-six had benign ovarian tumors and 17 had malignant ovarian tumors confirmed by histopathologic examination. Intratumoral blood vessels, detected in 16 of the malignant tumors, consistently demonstrated low impedance to flow, with a pulsatility index (PI) always below 1. The PI of the intraovarian or intratumoral blood vessels was greater than 1 in 35 of the 36 benign tumors, although 11 had suspicious sonographic findings (P less than .01) and 14 had elevated CA 125 levels (P less than .001). The sensitivity and specificity of the preoperative PI in detecting malignant ovarian tumors were 94 and 97%, respectively. The sensitivity and specificity of preoperative suspicious sonographic findings in detecting malignant ovarian tumors were 94 and 69%, and those of elevated preoperative serum CA 125 levels were 82 and 61%, respectively. Our results suggest that transvaginal color flow imaging may be a useful clinical tool in the preoperative evaluation of ovarian masses.

Adult↗
PubMed1991

Fusion of mycoplasmas: the formation of cell hybrids.

Poly(ethylene glycol) (PEG 8000) can induce cell-cell fusion of Mycoplasma capricolum cells, and it can promote the formation of intergeneric hybrids of various Mycoplasma, Acholeplasma and Spiroplasma species. The extent of fusion was quantitatively evaluated by following the dequenching of octadecylrhodamine fluorescent label incorporated into donor cell membranes after their incubation with recipient cells. The results of dequenching experiments were confirmed by electron microscopy, as well as by angle light-scattering measurements. Fusion appeared to require the presence of Mg2+, but was completely inhibited by either 0.1% glutaraldehyde or 100 microM chlorpromazine, and was partially suppressed by proteolytic enzymes, carbonyl cyanide-m-chlorophenylhydrazone, or thiol reagents.

Acholeplasma laidlawii↗
PubMed1991

Classification of tubal gestations by transvaginal sonography.

Transvaginal sonographic images of tubal pregnancies were correlated with the surgical findings in 191 patients having this condition. The sonographic appearance of the ectopic gestations was classified by the absence or presence of structures such as a 'tubal ring' containing the yolk sac, embryonic structures, heart activity, a sonolucent or irregularly echogenic gestational sac, dilated Fallopian tube with amorphous content, fluid in the pelvis and an empty uterus. The following classifications were made: Type Ia (n = 43) A well-defined 'tubal ring' and a beating heart with or without discrete embryonic or extra-embryonic structures. Type Ib (n = 48) A 'tubal ring' containing embryonic and/or extra-embryonic structures without heart beats. Type II (n = 64) An ill-defined or thin tubal wall containing sonolucent or an irregularly echogenic core but not embryonic or extra-embryonic structures. Type III (n = 28) Free pelvic fluid and an empty uterus in patients with positive serum beta-hCG levels. The outline of the tube cannot be visualized. Surgery revealed unruptured tubal pregnancies in 90 patients of the combined groups of Types Ia and Ib. In one additional patient, a tubal rupture was found. In the Type II patients, 26 tubal pregnancies with blood clots in the tube but no evidence of bleeding into the pelvis, and 38 tubal ruptures or abortions were diagnosed. All Type III patients had ruptured tubal pregnancies or bleeding tubal abortions. In eight patients (4.2%), the only sonographic finding was an empty uterus, and these cases were erroneously diagnosed as not having an ectopic pregnancy (false negatives). There were two false-positive cases in which a tubal ring was detected, and this was related to an hemorrhagic corpus luteum. When used for diagnosing tubal pregnancy, the transvaginal scanning technique (together with beta-hCG in Type III cases) carries a sensitivity of 95.8% and specificity of 99.9%. It is an invaluable tool in the diagnostic work-up and management of patients with suspected ectopic gestation.

Journal Article↗
PubMed1991

Small unilamellar vesicles are able to fuse with Mycoplasma capricolum cells.

We have investigated the fusion characteristics of intact Mycoplasma capricolum cells and small unilamellar vesicles (SUV). The rate and extent of fusion was monitored continuously by octadecylrhodamine B (R18) fluorescence dequenching assay, as well as by intracellular contents mixing, and by sucrose density gradient analysis. The fusion of SUV with M. capricolum cells was found to be dependent on poly(ethylene glycol) (PEG 8000), divalent cations in the medium, and on the cholesterol content of the lipid vesicles. Maximal levels of fusion were obtained with SUV containing 40 mol% cholesterol in the presence of 5% PEG. The rate and extent of fusion were affected by temperature, pH, osmotic pressure, and SUV/mycoplasma ratio. Under optimal fusion conditions, PEG did not increase the rate of exchange of either cholesterol or phospholipids between M. capricolum cells and SUV. Throughout the fusion process, M. capricolum cells remained intact as measured by the retention of [3H]thymidine-labeled components, and viable. M. capricolum cells were rendered nonfusogenic by treatment with glutaraldehyde (greater than 0.01%) or chlorpromazine (greater than 10 microM). Fusion was partially inhibited by treating the cells with the uncoupler CCCP (5 microM) or proteolytic enzymes, suggesting that a proton gradient across the cell membrane is required for the fusion, and that the cells possess proteinase-sensitive receptors that are responsible for a tighter contact with the lipid vesicles.

Cell Fusion↗
PubMed1990

In vitro induction of tumor necrosis factor alpha, tumor cytolysis, and blast transformation by Spiroplasma membranes.

Membranes of Spiroplasma sp. strain MQ-1 (hereafter referred to as MQ-1) were potent inducers of tumor necrosis factor alpha (TNF alpha) secretion and of blast transformation. Specific anti-recombinant murine TNF alpha antibodies markedly inhibited macrophage-mediated tumor cytolysis of A9 fibrosarcoma target cells following activation by MQ-1 membranes. Thus, TNF alpha plays a major role in mediation of tumor cytolysis induced by MQ-1 membranes, which is similar to its role in lipopolysaccharide (LPS)-induced tumor cytolysis. Two findings, however, suggested that the mechanism of macrophage activation by MQ-1 membranes differs from that by LPS: (a) macrophages, taken from C3H/HeJ mice showing a low responsiveness to LPS, were activated by MQ-1 membranes to enhanced TNF alpha secretion, resulting in a high-level tumor cytolysis compared with the negligible tumor cytolysis induced by LPS; and (b) MQ-1 membranes and LPS synergized to highly augment TNF alpha secretion by macrophages of C57BL/6 mice. MQ-1 membranes were capable of inducing blast transformation of murine lymphocytes as well. In addition, they activated human monocytes to secrete high levels of TNF alpha. Further studies need to be carried out using in vivo models to evaluate the therapeutic potential of MQ-1 membranes in the treatment of malignant diseases.

Animals↗
PubMed1990

Cloning, characterization, and expression in Escherichia coli of the gene coding for the CpG DNA methylase from Spiroplasma sp. strain MQ1(M.SssI).

We describe here the cloning, characterization and expression in E. coli of the gene coding for a DNA methylase from Spiroplasma sp. strain MQ1 (M.SssI). This enzyme methylates completely and exclusively CpG sequences. The Spiroplasma gene was transcribed in E. coli using its own promoter. Translation of the entire message required the use of an opal suppressor, suggesting that UGA triplets code for tryptophan in Spiroplasma. Sequence analysis of the gene revealed several UGA triplets, in a 1158 bp long open reading frame. The deduced amino acid sequence revealed in M.SssI all common domains characteristic of bacterial cytosine DNA methylases. The putative sequence recognition domain of M.SssI showed no obvious similarities with that of the mouse DNA methylase, in spite of their common sequence specificity. The cloned enzyme methylated exclusively CpG sequences both in vivo and in vitro. In contrast to the mammalian enzyme which is primarily a maintenance methylase, M.SssI displayed de novo methylase activity, characteristic of prokaryotic cytosine DNA methylases.

Amino Acid Sequence↗
PubMed1990

Transvaginal sonographic technique: targeted organ scanning without resorting to "planes".

The orientation of the sonographer performing a transvaginal scan is currently based on a concept of anatomical planes, which is customary in transabdominal sonography. We challenge this concept and propose a different approach altogether based on focusing on target organs rather than anatomic planes. The problem of orientation in transvaginal sonography stems from the following: (1) There is a very short distance between the relatively high-frequency transvaginal transducer-probe and the scanned area; a close-up image is generated encompassing a single organ or only part of it. (2) The scanning angle is initially perpendicular to that of abdominal sonography. (3) Transvaginal sonography is an endocavitary dynamic scanning technique. According to the experience in our department (30,000 examinations during the past 4 years) and in two other medical centers, best results from the transvaginal ultrasonographic examination are achieved when the operator searches for every specific organ as the main target, without resorting to pelvic "planes." The guidelines for targeted organ scanning and the associated change in orientation are reported together with the limitations. Targeted organ scanning without resorting to "planes" helps the operator to resolve the problem of orientation during the transvaginal ultrasonographic examination, and to simplify the procedure to a great extent.

Fallopian Tubes↗
PubMed1990

Criteria for transvaginal sonographic diagnosis of ectopic pregnancy.

Transvaginal ultrasonography was performed in 1150 patients suspected of having an ectopic gestation. The criteria for transvaginal sonographic diagnosis of ectopic pregnancy were established by targeted scanning of the pelvic organs and spaces. Sonographic assessment of tubal pregnancy and its differential diagnosis were based on six criteria: (1) the presence or absence of gestational structures within the fallopian tube, (2) the presence or absence of amorphous material in a dilated fallopian tube, (3) the presence or absence of indirect signs of ectopic pregnancy within the pelvis, (4) the echogenicity of a suspected finding relative to the ovary, (5) the presence or absence of flow (of lacunar origin) within the suspected sonographic finding, and (6) the relationship of a suspected sonographic sign to an intentionally displaced ovary. The latter 3 criteria help differentiate between tubal gestation and a corpus luteum. We believe these diagnostic criteria should be applied when performing transvaginal sonographic scanning of patients suspected of having an ectopic gestation.

Corpus Luteum↗
PubMed1990

Early determination of fetal sex using transvaginal sonography: technique and pitfalls.

Transvaginal sonography (TVS) enables sex determination at an early stage of pregnancy. The morphologic features of fetal external genitalia at 13 weeks to 16 weeks, menstrual age, are different from those seen later in pregnancy; therefore an attempt to determine fetal gender at this early stage by the same criteria as those used later is hazardous, especially for determining the male sex. The main diagnostic criteria for male gender determination by TVS are the "dome" sign representing the sonographic visualization of the fetal scrotum, the cranially directed phallus, and the longitudinal raphe at the base of the penis. The diagnostic criteria for female gender are the 2 or 4 parallel lines representing the labial folds and the caudally directed phallus (clitoris). The length of the fetal phallus at this early stage is not diagnostic and may be the main pitfall to the unexperienced sonographer. Between weeks 13 and 14 sex diagnosis was possible in 130/171 pregnancies (76%) in our first 2 years and 188/235 (80%) in our last 2 years of experience. Between weeks 15 and 16 sex diagnosis was possible in 122/139 pregnancies (88%) during our first 2 years and 96.7% (528/546) during the last 2 years of experience. The accuracy rate for fetal male gender identification increased from 91.7% during the first 2 years of TVS experience to 99.7% during the last 2 years of TVS experience, and the accuracy rate for female gender identification, increased from 93.3% to 100%, respectively, applying the above criteria and based on acquired experience of early fetal sex identification by TVS early in gestation. Early and precise determination of fetal sex is possible and might avoid invasive procedures such as amniocentesis.

Female↗
PubMed1990

Transvaginal sonographic diagnosis of congenital anomalies between 9 weeks and 16 weeks, menstrual age.

A 6.5-MHz transvaginal probe was employed for the screening of congenital malformations in 1652 patients between 9 weeks and 16 weeks, menstrual age. Transvaginal sonography detected 61 malformations in 40 fetuses. The overall diagnostic frequency of the congenital anomalies in this series was 2.6%. As described in this study, several congenital malformations are now detectable before the 16th week, and transvaginal sonography appears to be the diagnostic method of choice for the first and early second trimester.

Congenital Abnormalities↗
PubMed1990

First trimester selective reduction in multiple pregnancy guided by transvaginal sonography.

Transvaginal ultrasonography-guided fetal reduction was performed in 11 patients presenting with multiple pregnancies. Embryonic aspiration was carried out in 7 women at 7 to 8 weeks and in 4 patients fetal intrathoracic injection was performed at 9 to 11 weeks, menstrual age. Seven patients delivered healthy babies at greater than 35 weeks, 3 have delivered prematurely 15 to 17 weeks after the procedure with subsequent neonatal death of all sets of twins. We believe that our method overcomes the technical difficulties related to the transabdominal or transcervical approach and should be the method of choice for early selective abortion.

Abortion, Induced↗
PubMed1990

The uterus: a new look with transvaginal sonography.

Targeted scanning of the uterus and its adjacent structures is made possible by high-resolution transvaginal sonography. A systematic approach is applied so that the normal anatomy and abnormal processes in the various uterine components can be visualized. By adopting this method we detected various pathologies in the cervix, endometrium, myometrium, and in the uterine vessels and ligaments. Cervical pathology included inflammatory processes, cysts, malignant lesions, and incompetence during pregnancy. By scanning the endometrium, a reflection of the hormonal status of the patient under both normal (e.g., the menstrual cycle) and abnormal conditions may be obtained. More sinister lesions, such as endometrial hyperplasia and carcinoma, can be suspected based on the sonographic appearance of the endometrium. In hydatiform mole, a typical sonographic picture directs the sonographer to the diagnosis. Uterine fibroids are the most common lesion of the corpus uteri, and are readily detected by transvaginal sonography, including any degenerative changes that may complicate this condition. Changes in uterine size, particularly when accompanied by profuse intracavitary fluid, should raise the suspicion of a malignant process. Intracavitary fluid may also be associated with inflammatory lesions (e.g., tuberculosis). Congenital uterine anomalies may be diagnosed and defined by this method. Uterine ligaments are best visualized in the presence of fluid in the pelvis. Intraligamentary masses can be also be detected and defined. Finally, the main vessels supplying the uterus can be visualized, both in pregnant and nonpregnant patients. Using a transvaginal image-directed Doppler system, flow velocity profiles can be obtained from these vessels and form the basis for defining abnormalities in uterine perfusion.

Adolescent↗
PubMed1990

Classification of ovarian lesions by high-frequency transvaginal sonography.

Two hundred patients suspected of having ovarian pathology were scanned with a 6.5-MHz transvaginal probe. Normal anatomical structures and abnormal findings were recorded and classified according to their shape, size, location, and sonographic characteristics. The sonographic images were correlated with the surgical findings, whenever available. A sonographic classification of ovarian lesions was compiled according to the presence or absence of the following sonographic components: septae, papillae, loculations, daughter cysts, solid mass, or fluid, and their relationship to malignancy.

Female↗
PubMed1990

Hemodynamic evaluation of the female pelvic vessels using a high-frequency transvaginal image-directed Doppler system.

Perfusion characteristics of the female pelvic vessels were studied by a high-frequency transvaginal image-directed Doppler system. A 5-MHz Doppler transducer was coupled to a 6.5-MHz probe especially designed for intravaginal use. Distinct patterns of flow velocity waveforms were obtained from the ascending branch of the uterine artery, before and during pregnancy. A gradual increase in diastolic flow throughout gestation was observed, consistent with a decrease in vessel resistance. Flow velocity profiles in the ovarian artery were sampled from the infundibulo-pelvic ligament. Only limited diastolic flow could be detected in either ovary during the follicular phase of the cycle. In the luteal phase there was a marked increase in this flow but only in the ovary containing the corpus luteum. In early pregnancy the high diastolic flow was maintained or even increased, consistent with a low arterial resistance. High image resolution and a higher frequency Doppler transducer increase the usefulness of this technique in the hemodynamic evaluation of the female pelvic vessels.

Blood Flow Velocity↗