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M M Sanders

Publications and source records attributed to M M Sanders.

68 records · Page 4Linked to original sources
PubMed1981

Differential processing of the two subunits of human choriogonadotropin by granulosa cells. II. In vivo studies.

Using a well characterized preparation of hCG, consisting of a mixture of hCG labeled in the alpha-subunit with 125I and hCG labeled in the beta-subunit with 131I (see preceding paper), the hormone-specific preferential retention by granulosa cells in vivo of the radiolabel originally associated with the beta-subunit of hCG has been confirmed and extended. Additional studies have shown that this retention is peculiar to the granulosa cells. Luteal and interstitial/thecal elements of the ovary failed to show preferential accumulation of the label originally associated with the beta-subunit. Measurement of both radioactivities in crude subfractions of the ovarian tissues revealed that granulosa cells retain the excess of beta-subunit label in a plasma membrane/vesicular component. No such preferential retention of label was seen in any of the subfractions obtained from luteal or interstitial/thecal tissues. The radiolabeled components associated with the granulosa cells were shown to be mainly macromolecular by their precipitability with 13% trichloroacetic acid. Luteal tissue degraded the components associated with each label more rapidly than granulosa cells. In contrast, interstitial/thecal tissue degraded very little of the bound labeled components. The differential processing of individual hCG subunits by granulosa cells was shown not to result from different kinetics of binding of serum-borne hormone by two methods. Thus, changes over time in the ability of circulating hormone to bind to LH receptor in vitro were shown not to be a function of the hCG subunit having the label. Moreover, blockade of further radiolabel uptake by injection of a large excess of unlabeled hCG 30 min after radiolabel administration did not alter the rise in the ratio of beta-subunit label to alpha-subunit label normally observed in granulosa cells. The ability of kidney tissue to accumulate and metabolize hCG also varied with the physiological state. Within the limitations of following the radioiodides added to proteins rather than the peptides themselves, these studies demonstrate that differences exist in the metabolism of hCG by the various target cells of the ovary and that changes in processing occur during luteinization.

Animals↗
PubMed1978

Fractionation of nucleosomes by salt elution from micrococcal nuclease-digested nuclei.

The solubilization of nucleosomes and histone H1 with increasing concentrations of NaCl has been investigated in rat liver nuclei that had been digested with micrococcal nuclease under conditions that did not substantially alter morphological properties with respect to differences in the extent of chromatin condensation. The pattern of nucleosome and H1 solubilization was gradual and noncoordinate and at least three different types of nucleosome packing interactions could be distinguished from the pattern. A class of nucleosomes containing 13--17% of the DNA and comprising the chromatin structures most available for micrococcal nuclease attack was eluted by 0.2 M NaCl. This fraction was solubilized with an acid-soluble protein of apparent molecular weight of 20,000 daltons and no histone H1. It differed from the nucleosomes released at higher NaCl concentrations in content of nonhistone chromosomal proteins. 40--60% of the nucleosomes were released by 0.3 M NaCl with 30% of the total nuclear histone H1 bound. The remaining nucleosomes and H1 were solublized by 0.4 M or 0.6 M NaCl. H1 was not nucleosome bound at these ionic strengths, and these fractions contained, respectively, 1.5 and 1.8 times more H1 per nucleosome than the population released by 0.3 M NaCl. These fractions contained the DNA least available for micrococcal nuclease attach. The strikingly different macromolecular composition, availability for nuclease digestion, and strength of the packing interactions of the nucleosomes released by 0.2 M NaCl suggest that this population is involved in a special function.

Cell Nucleus↗
PubMed1977

Fractionation of purified nucleosomes on the basis of aggregation properties.

Monomeric nucleosomes from micrococcal nuclease digest of rat liver nuclei have been purified on Sepharose columns in the presence of divalent cations and 0.6 M NaCl. The particles contain histones H2A, H2B, H3, H4, and a complement of nonhistone chromosomal proteins. In 0.6 M NaCl, the nucleosome mixture sedimented at 10 S; however, when the NaCl was removed approximately 30% of the particles aggregated and precipitated, and the remaining soluble fraction sedimented at 11 S. The aggregation phenomenon was divalent cation-dependent and reversible. Characterization of the macromolecular components of the subfractions of nucleosomes showed that the subfractions differed in composition of species of histone H3 as well as of several nonhistone chromosomal proteins but not in the size of the DNA fragment present. The aggregation properties of the isolated nucleosomes showed similarities to the divalent cation-dependent differences in the extent of chromatin condensation in the intact eukaryote nucleus.

Animals↗
PubMed1976

Presence of histones in Aspergillus nidulans.

Five major histone proteins have been extracted from chromatin isolated from purified nuclei of the fungus, Aspergillus nidulans. These proteins had chromatographic properties which were similar to reference calf thymus histones and were purified to electrophoretic homegeneity by gel chromatography of Bio-Gel P10, Bio-Gel P60, and Sephadex G-100. Electrophoresis of these proteins in three different systems (urea-starch, urea-acetic acid polyacrylamide, and discontinuous SDS polyacrylamide) showed that the A. nidulans histones H3 and H4 were nearly identical to calf thymus H3 and H4 with respect to net charge and molecular weight criteria, whereas the fungal histones H1, H2a and H2b were similar but not identical to the corresponding calf thymus histones. Amino acid analysis of A. nidulans histones H2a, H2b, and H4 showed them to be closely related to the homologous calf thymus histones. The mobility patterns of A. nidulans ribosomal basic proteins in three different electrophoretic systems were distinctly different from those of the fungal histones.

Amino Acids↗
PubMedDate not supplied

Increased incidence of oviduct pathology in the guinea pig after repeat vaginal inoculation with the chlamydial agent of guinea pig inclusion conjunctivitis.

BACKGROUND AND OBJECTIVES: Although it has been hypothesized that repeated infections with Chlamydia trachomatis result in an increased potential for the development of infertility, it is not know whether repeated chlamydial infection by the vaginal route will result in an increased incidence of upper tract pathology or enhanced pathology. GOAL OF THIS STUDY: To determine whether guinea pigs given two infections with the chlamydial agent of guinea pig inclusion conjunctivitis would experience an increased incidence of pathologic changes compared with animals having only a single infection. STUDY DESIGN: Guinea pigs previously infected with guinea pig inclusion conjunctivitis were challenged with a fresh intravaginal inoculum 73-77 days after the primary infection. Oviducts were examined either nine or 30 to 37 days after the challenge infection for pathologic changes and compared with control unchallenged animals 75 to 85 days after a primary infection. RESULTS: A significant increase in the number of animals with oviducts demonstrating marked tubal dilatation was observed in the challenged animals 30 to 37 days after the challenge infection. There was no association of increased antibody titer and chlamydial Hsp60 with the presence of tubal dilatation. CONCLUSION: These data strongly indicate that repeated infection via the natural vaginal route does increase the risk of tubal damage.

Animals↗
PubMedDate not supplied

Fine needle aspiration in the diagnosis of liver neoplasms: a review.

Fine needle aspiration biopsy (FNAB) for the diagnosis of liver neoplasms is a safe, rapid, and accurate technique. It is most useful in patients with a hepatic mass(es) and a previously diagnosed malignant neoplasm. With the current application of immunocytochemical techniques, accurate cytologic diagnoses can be made in most primary and secondary hepatic neoplasms. The equipment necessary to perform FNAB is simple, inexpensive, and readily available. The principle of this technique is to obtain a representative cellular aspirate via a small bore needle and produce a stained image on a microscopic slide that reflects the disease process in the patients. Techniques and clinical skills of FNAB and experiences of interpretation are required to make maximal use of this diagnostic modality.

Biopsy, Needle↗
PubMedDate not supplied

Acute and chronic toxic nephropathies.

Toxic nephropathies manifest morphologically as glomerulonephritides, vasculitides, tubular necrosis, and acute or chronic tubulointerstitial disease. The most common toxicity is acute interstitial nephritis owing to hypersensitivity. However, focal segmental glomerulosclerosis and necrotizing angiitis secondary to heroin abuse, membranous glomerulopathy owing to gold, penicillamine and captopril, thrombotic microangiopathy associated with mitomycin and tubular necrosis owing to cyclosporine A, cisplatin, aminoglycosides, and cephalosporins are also reviewed. The mechanisms of toxicity are poorly understood in most cases, but hypotheses related to cyclosporine A, cisplatin, gold, aminoglycosides, cephalosporins, intravenous narcotics, sulfonamides, and methotrexate are summarized.

Acute Disease↗
PubMedDate not supplied

Current status of radioligand antibodies in the treatment of malignancy.

Monoclonal anti-tumor antibodies labeled with a radioactive moiety present an exciting new approach to cancer therapy. With the advent of hybridoma technology, monoclonal antibodies can now be produced in quantity. Indeed, antibodies against tumor-related and tumor-specific antigens have been produced, labeled with a radioactive substance, and used therapeutically. The rationale for this therapeutic approach and the results of human clinical trials will be reported herein.

Antibodies, Monoclonal↗
PubMedDate not supplied

Anaplastic carcinoma following well-differentiated thyroid cancer: etiological considerations.

Most cases of anaplastic thyroid carcinoma can be pathologically and often historically associated with the presence of low-grade (differentiated) cancer in the thyroid. That radiation therapy to the differentiated tumor plays an etiologic role in the transformation of a differentiated to an undifferentiated tumor has been suggested. If such therapy can be implicated, is there a difference in risk between external radiotherapy or radioactive iodine? Review of the literature discloses that more anaplastic carcinoma of the thyroid develop in patients without a history of prior radiation than in individuals who have received radiation. We report our recent experience with two patients who demonstrated the sequence of well-differentiated followed by anaplastic thyroid cancer subsequent to radiation and review the question.

Aged↗
PubMedDate not supplied

Cell populations in the bone marrow of guinea pig fetuses with intrauterine growth retardation.

Bone marrow smears and blood samples were examined in guinea pig fetuses in which intrauterine growth retardation (IUGR) had been induced by uterine artery ligation and compared with those of control (well-grown) fetuses from uterine horns with intact circulation. Differential bone marrow cell counts were obtained from a count of 300 cells per smear and blood samples were assayed for hemoglobin concentration and 2,3-diphosphoglycerate (DPG). Results of blood assays showed no difference in hemoglobin concentration. DPG levels were reduced in the IUGR guinea pigs (P < .05), which could be a consequence of decreased glucose availability or represent an adaptation to reduced oxygen availability. Comparisons of bone marrow counts revealed an increase in total erythrocyte precursors (P < .05) and a decrease in total granulocytic precursors (P < .05) in IUGR fetuses. Within the erythroid lineage there was a significant increase in late (orthochromatic) erythroblasts (P < .005) in the IUGR animals compared with control animals. The granulocytic lineage of the IUGR fetuses showed a significant decrease in mature neutrophils (P < .05) and eosinophilic precursors (P < .05) compared with controls. These data suggest that the hypoxic stress of uterine artery ligation leads to an increase in medullary erythropoiesis. In concert with a previous study that showed a reduction in hepatic erythropoiesis, these data suggest a precocious shift of the anatomic site of erythropoiesis from the liver to the bone marrow under conditions of hypoxia.

2,3-Diphosphoglycerate↗