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Biomedical subjects

D Manor

Publications and source records attributed to D Manor.

At least 73 records · Page 4Linked to original sources
PubMed1991

Resonance Raman studies of the HOOP modes in octopus bathorhodopsin with deuterium-labeled retinal chromophores.

Resonance Raman spectra of the hydrogen out-of-plane (HOOP) vibrational modes in the retinal chromophore of octopus bathorhodopsin with deuterium label(s) along the polyene chain have been obtained. In clear contrast with bovine bathorhodopsin's HOOP modes, there are only two major HOOP bands at 887 and 940 cm-1 for octopus bathorhodopsin. On the basis of their isotopic shifts upon deuterium labeling, we have assigned the band at 887 cm-1 to C10H and C14H HOOP modes, and the band at 940 cm-1 to C11H = C12H Au-like HOOP mode. Except for a 26 cm-1 downward shift, the C11H = C12H Au-like wag appears to be little disturbed in octopus bathorhodopsin from the chromophore in solution since its changes upon deuterium labeling are close to those found in solution model-compound studies. We found also that the C10H and C14H HOOP wags are also similar to those in the model-compound studies. However, we have found that the interaction between the C7H and C8H HOOP internal coordinates of the chromophore in octopus bathorhodopsin is different from that of the chromophore in solution. The intensity of the C11H = C12H and the other HOOP modes suggests that the chromophore of octopus bathorhodopsin is somewhat torsionally distorted from a planar trans geometry. Importantly, a twist about C11 = C12 double bond is inferred. Such a twist breaks the local symmetry, resulting in the observation of the normally Raman-forbidden C11H = C12H Au-like HOOP mode. The twisted nature of the chromophore, semiquantitatively discussed here, likely affects the lambda max of the chromophore and its enthalpy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Growth of human normal erythroid progenitors in liquid culture: a comparison with colony growth in semisolid culture.

Most studies of erythropoiesis in vitro have employed cloning methods in semisolid medium. We have recently described a two-step liquid culture procedure that supports the proliferation and differentiation of human erythroid progenitors. In the present study, we have modified the procedure to allow large-scale cultures of erythroid cells derived from normal donors. The culture is divided into two phases. In the first phase, which is erythropoietin (Epo) independent, the early erythroid progenitors multiply and differentiate. In the second, Epo-dependent phase, they mature into orthochromatic normoblasts and enucleated erythrocytes. Using this procedure, erythroid cell yield reached 7.5 x 10(6)/ml and a total of 7 x 10(8) cells could be harvested per blood unit. A comparison of the growth of erythroid cells in liquid culture to their colony growth in semisolid culture indicated that cell growth was superior: 1) in liquid culture in terms of cell yield per originally cultured mononuclear cell, 2) per ml culture and per culture surface area and in the purity of the resultant erythroid cell population. In addition, it permits easier manipulation of the culture condition and components and sampling of greater than 1 x 10(7) cells at each maturation stage subsequent to the proerythroblast stage. This liquid culture procedure might provide an important experimental tool for studying erythroid cell development.

Cell Division↗
PubMed1991

A resonance Raman study of octopus bathorhodopsin with deuterium labeled retinal chromophores.

The resonance Raman spectrum of octopus bathorhodopsin in the fingerprint region and in the ethylenic-Schiff base region have been obtained at 80 K using the "pump-probe" technique as have its deuterated chromophore analogues at the C7D; C8D; C8,C7D2; C10D; C11D; C11, C12D2; C14D; C15D; C14, C15D2; and N16D positions. While these data are not sufficient to make definitive band assignments, many tentative assignments can be made. Because of the close spectral similarity between the octopus bathorhodopsin spectrum and that of bovine bathorhodopsin, we conclude that the essential configuration of octopus bathorhodopsin's chromophore is all-trans like. The data suggest that the Schiff base, C = N, configuration is trans (anti). The observed conformationally sensitive fingerprint bands show pronounced isotope shifts upon chromophore deuteration. The size of the shifts differ, in certain cases, from those found for bovine bathorhodopsin. Thus, the internal mode composition of the fingerprint bands differs somewhat from bovine bathorhodopsin, suggesting a somewhat different in situ chromophore conformation. An analysis of the NH bend frequency, the Schiff base C = N stretch frequency, and its shift upon Schiff base deuteration suggests that the hydrogen bonding between the protonated Schiff base with its protein binding pocket is weaker in octopus bathorhodopsin than in bovine bathorhodopsin but stronger than that found in bacteriorhodopsin's bR568 pigment.

Animals↗
PubMed1991

Effect of calcium channel blocker nifedipine on uterine artery flow velocity waveforms.

Calcium channel blockers have been used successfully in the treatment of pregnancy hypertension and premature labor. Only limited information related to their effect on uterine blood flow during pregnancy is available. In this study we measured the ratio between peak systolic to end-diastolic flow velocity (S/D ratio) in the ascending branch of the uterine artery in nine pregnant patients prior to and following a 10-mg dose of sublingual nifedipine. Another group of seven matched patients who received a placebo served as a control group. All studies were performed between 17 and 22 weeks gestation. The S/D ratio decreased shortly after sublingual nifedipine, but the change was not significant. It increased gradually afterward so that by 60 minutes it returned to the control value. The mean systolic blood pressure decreased by 8.6% to its lowest value after 25 minutes (P less than 0.01). The mean diastolic blood pressure decreased by 15.7% to its lowest value after 35 minutes (P less than 0.002). Maternal heart rate did not change significantly. No significant changes were observed in any of the measured variables in the placebo group. In conclusion, nifedipine does not induce significant changes in uterine arterial resistance in midtrimester and may be considered during pregnancy, providing that large fluctuations in maternal blood pressure are avoided.

Arteries↗
PubMed1990

Transvaginal imaging: applied physical principles and terms.

In this article the properties of ultrasound in tissues and the factors governing image quality are discussed. Particular emphasis is placed on the vaginal probe. The virtues of transvaginal scanning both in gynecology and obstetrics are well described in subsequent articles in this symposium. Only by understanding the properties of ultrasound can the capabilities and limitations of this technique be appreciated. A comprehensive knowledge of the basic physical principles is mandatory for the clinician as well the investigator to attain the highest quality results. The technical aspects of operating ultrasound instruments, e.g., machine controls, electronic image formation, scan converters and techniques for preprocessing and postprocessing, are not discussed.

Female↗
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↗
PubMed1990

Changes in uterine blood flow during human pregnancy.

A transvaginal duplex Doppler ultrasonography system was used to measure blood flow characteristics in the ascending uterine artery before and during pregnancy. The system uses a 5 MHz Doppler transducer coupled to a 6.5 MHz imaging probe. There was a steady increase in volume flow rate in the left ascending uterine artery from a mean of 94.5 ml/min before pregnancy to a mean of 342 ml/min in late gestation (reflecting a 3.5-fold increase). With the assumption of equal flow on both uterine arteries, the fraction of the cardiac output that is distributed to these vessels was calculated to be 3.5% in early pregnancy and to reach 12% near term. The mean diameter of this vessel in the nonpregnant state was 1.6 mm, increasing to 3.7 mm toward term. The resistance to flow, expressed as the peak systolic to end-diastolic flow velocity ratio, declined from a mean of 5.3 in the nonpregnant state to a mean of 2.3 near term. These changes reflect the perpetual growth and development of the uteroplacental circulation, which provides the metabolic demands of the growing fetus throughout gestation.

Arteries↗
PubMed1990

Human sperm and hamster oocyte interaction: a model system to assess sperm entry into the oocyte after partial zona dissection.

A model system of hamster oocyte and human sperm interaction was used to assess sperm entry into the perivitelline space after partial zona dissection. The procedure of zona dissection was standardized by creating slits which included one fourth, one eighth, one eighth X 2, or one sixteenth of the zonal circumference. Manipulated eggs were allowed to interact with 1 X 10(6) sperm/mL for 3 hours. A single large or medium slit was equally effective in permitting sperm entry into 46% and 47% of the manipulated eggs, respectively. However, the longer slit doubled the average number of sperm detected in the perivitelline space. A second medium-sized slit increased the rate of sperm entry into the perivitelline space to 76%, but the incidence of damaged oocytes also increased. A small slit did not permit sperm entry into any of the manipulated oocytes. This heterologous system of gamete interaction provides a model to evaluate requirements for successful partial zona dissection or other related procedures for assisted fertilization in the human.

Animals↗
PubMed1990

A constitutive antibody in normal human serum directed against rabbit bone marrow cells: lack in parturients, neonates, and hematologic disorders.

Normal human serum effectively inhibits a bioassay for erythropoietin based on DNA synthesis by rabbit erythroid precursors. This heat-sensitive inhibitory activity is readily lost on dilution of serum, revealing the presence of erythropoietin-potentiating activity. Inhibitory activity is caused by a rapid cytotoxic effect on rabbit bone marrow cells; mouse cells are less sensitive. Cytotoxic activity is removed from serum by adsorption to protein A, is not expressed at 4 degrees C, and is neutralized by anti-C3c complement antibody. Cytotoxicity is inhibited by EGTA; the effect of EGTA is reversed by addition of Ca2+ ions. These findings show that cytotoxicity is exerted through an antibody via the classical pathway of complement-dependent cell lysis. Although serum from healthy, adult human donors consistently contains cytotoxic activity, no such activity is observed in most serum samples from neonates, parturients, and patients with severe anemia. Patients with polycythemia or chronic renal failure occasionally lack cytotoxic activity in their serum. Serum samples lacking cytotoxic activity were found to be deficient in the antibody component in 34 out of 35 cases examined. These results show that an antibody directed against rabbit cells is constitutively present in normal human serum but is absent in a number of pathologic situations as well as being absent in neonates and parturients.

Anemia↗
PubMed1989

Muscle fibre necrosis induced by intramuscular injection of drugs.

A number of amphiphilic and lipid-soluble drugs of heterogeneous pharmacological properties, when injected into rat anterior tibial muscles, induced acute muscle fibre necrosis. The myotoxic agents were: penicillin, cloxacillin, phenobarbital, haloperidol, diazepam, hydantoin, metoclopramide, pentazocine and chlorpromazine. The regenerative process, studied using the latter three medications, showed rapid regeneration, complete within 3 weeks. Injection of the water-soluble drugs aminophylline, tranexamic acid and vitamins B6 and B12 produced no tissue damage. The pathogenesis of muscle fibre necrosis is suggested to involve direct damage to cell membranes by lipid soluble drugs.

Animals↗
PubMed1989

Proliferation and maturation of human erythroid progenitors in liquid culture.

Hemopoiesis is studied in vitro mainly in semisolid culture, where hemopoietic progenitors develop into discrete colonies. We describe a liquid culture system that supports the proliferation and maturation of human erythroid progenitors. We seeded mononuclear cells from the peripheral blood (PB) of patients with beta-thalassemia in liquid medium in the presence of conditioned medium from human bladder carcinoma cells. Seven days later, RBCs, normoblasts, granulocytes, and monocytes disappeared, and the number of lymphocytes dropped considerably. In contrast, erythroid colony-forming cells increased fourfold to tenfold. The next step entailed the removal of colony-stimulating factor (CSF) and CSF-secreting cells, the exclusion of macrophages by harvesting nonadherent cells, and the lysis of T lymphocytes by treatment with monoclonal rat antihuman lymphocyte antibodies (CAMPATH-1) and complement. Reculture of the remaining cells in liquid medium supplemented with recombinant erythropoietin (EPO) resulted in the exclusive development of erythroid cells, with myeloid cells reduced to less than 2%. Stainable hemoglobin (Hb) appeared on day 3, with over 85% of the population containing hemoglobin by day 11 and the cell number increasing from 0.2 X 10(6) to 3 X 10(6) mL. By permitting the manipulation of culture conditions and components and increasing the cell yield, the liquid system may facilitate quantitative analysis of growth kinetics as well as biochemical and immunologic characterization of the developing erythroid cell.

Cell Count↗
PubMed1988

Membrane potential modulates photocycling rates of bacterial rhodopsins.

Effects of membrane potential on photochemical reactions of three retinal-containing chromoproteins in Halobacterium halobium, sensory rhodopsin I (sR-I), bacteriorhodopsin, and halorhodopsin, are described. Each of the three exhibits a decreased rate of thermal decay of its principal intermediate when photoactivated in an artificially energized compared to a deenergized membrane. The similar response of the three pigments suggests a voltage-dependent conformational change common to their respective photocycles. Spectral and kinetic properties of the sR-I photochemical reaction cycle were measured in phototactic H. halobium cells, and differences from in vitro photocycle kinetics were attributable to the electrical membrane potential present in vivo. In vivo sR-I photocycling rates were reproduced in envelope vesicle preparations in the presence of a valinomycin-induced potassium diffusion potential.

Halobacterium↗
PubMed1987

Metastatic brain tumor following negative second-look operation for ovarian carcinoma.

Three patients with stage III ovarian cancer had brain metastases following aggressive chemotherapy with Platinol and Adriamycin, and negative second-look surgery. The possibility of brain metastasis following complete control of intraperitoneal ovarian disease should be considered in patients with neurological symptoms.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Properties of a second sensory receptor protein in Halobacterium halobium phototaxis.

A second slow-cycling retinylidene protein, in addition to slow-cycling (sensory) rhodopsin (SR), can be bleached with hydroxylamine and regenerated with all-trans retinal in photosensory signaling Halobacterium halobium membranes. Flash photolysis shows this protein undergoes a photochemical reaction cycle characterized by photoconversion of its ground state (lambda max 480 nm) to a species with lambda max less than or equal to 360 nm, which thermally regenerates the 480-nm species with a t1/2 of 260 msec at 25 degrees C, under conditions in which SR photocycles at 650 msec in the same membranes. Mutants characterized with respect to their phototaxis behavior are identified which contain SR and the 480-nm pigment, the latter ranging from undetectable to a concentration equal to that of SR. Receptor mutants lacking all phototaxis sensitivity lack both of the photochemically reactive proteins. The mutant properties contribute to an accumulation of behavioral and spectroscopic evidence that the 480-nm pigment is a second sensory photoreceptor in H. halobium. NaDodSO4-polyacrylamide gel electrophoresis of [3H]retinal-labeled membrane proteins from the mutants indicates SR and the 480-nm pigment contain distinct chromophoric polypeptides differing in their migration rates. The data implicate polypeptides of 25,000 Mr and 23,000 Mr as retinal-binding polypeptides of SR and the 480-nm protein, respectively.

Bacterial Proteins↗
PubMed1986

Erythropoietin activity in the serum of beta thalassemic patients.

Serum erythropoietic activity was determined in 32 patients with beta thalassemia major and intermedia. Quantitation was performed by an in vitro bioassay using rabbit erythroid precursor cells (CFU-E) either by colony assay or by 3H-thymidine uptake. 20 polytransfused beta-thalassemic major patients had erythropoietic activity (mean 89.3 +/- 36 milliunits/ml) which was not significantly different (p greater than 0.2) from normal individuals (51.3 +/- 32 milliunits/ml). 12 untransfused patients with beta thalassemia intermedia were found to have comparable serum erythropoietic activity (p greater than 0.01). These levels were much lower than those found in patients with aplastic anemia who had a comparable degree of anemia. We have shown that the low EPO activity in thalassemic patients was not due to experimental conditions (excess of ferritin, low transferrin) nor to specific inhibitors appearing in this disease. No correlation was found between the erythropoietic activity and sex or other clinical parameters of the patients such as severity of the anemia, splenectomy, iron chelation or transfusion therapy. 4 young thalassemic children (1-2 yr of age) studied had high erythropoietic activity ranging from 661 to 5793 milliunits/ml--significantly different from normal children of the same age. It is suggested, therefore, that a decrease in serum erythropoietin levels develops during the course of the disease.

Anemia, Aplastic↗
PubMed1986

Enrichment for GM-CFU from human bone marrow using Sambucus nigra agglutinin: potential application to bone marrow transplantation.

A new lectin, purified from black elder-berries, Sambucus nigra L. (SNA I, hereafter called SNA), was used for fractionation of normal human marrow cells. The stem cell enrichment capability of SNA was investigated by comparing colony formation (GM-CFU) in unagglutinated cell fractions (SNA-) following agglutination with SNA with that with soybean agglutinin (SBA-). GM-CFU recovery in SNA- was equal or superior to that in the SBA- fraction. A modified procedure was developed to combine stem cell enrichment and depletion of E-rosette-forming T-lymphocytes. Bone marrow cells were exposed in one step to SNA and to untreated sheep red blood cells (SRBC). Nonagglutinated, nonrosetting cells were collected after Ficoll-Hypaque-gradient separation. The procedure, a modification of Reisner's multistep procedure involving the agglutination of SBA+ cells; separation of the unagglutinated SBA- cells from the top of a 5% bovine-serum-albumin gradient; the formation of E-rosettes with SRBC; and the separation of rosettes over a Ficoll-Hypaque gradient, is faster, simpler, and as effective for T-cell depletion and stem cell enrichment.

Bone Marrow Transplantation↗