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M M Miller

Publications and source records attributed to M M Miller.

At least 37 records · Page 2Linked to original sources
PubMed2000

Organization of telomere sequences in birds: evidence for arrays of extreme length and for in vivo shortening.

Telomeres are the specialized ends of chromosomes consisting of highly conserved repeat (5'-TTAGGG-3')(n) sequences. Lack of information regarding the existence of an in vivo telomere clock function in birds, conflicting data regarding telomere array length in the chicken model, and the paucity of molecular telomere information for other avian species led us to study telomere array organization within and among 18 species and subspecies of birds. Most of the species contained between 2% and 4% telomere sequence per diploid genome. Arrays spanning 0.5-10 kb (Class I) and 10-40 kb (Class II) were observed in all of the species studied. Extremely long arrays, ranging from hundreds of kilobases to 1-2 Mb (Class III) were observed in all except two raptor species, the northern goshawk and American bald eagle. In chicken, there was evidence for shortening of the Class II arrays in vivo, based on intraindividual comparisons of somatic versus germline tissues in birds of different ages; terminally differentiated erythrocyte arrays were, on average, 2.3 kb shorter than sperm (germline) arrays. This study provides the first evidence for the existence of telomere arrays significantly larger than have been described for any vertebrate species to date and for developmentally programmed in vivo telomere shortening in the Aves taxa. The novel finding of megabase-sized telomere arrays may be an important feature of avian karyotypes that contain a large number of very small genetic units, the microchromosomes.

Aging↗
PubMed1999

Effects of blood contamination of cerebrospinal fluid on western blot analysis for detection of antibodies against Sarcocystis neurona and on albumin quotient and immunoglobulin G index in horses.

OBJECTIVE: To determine effects of blood contamination on western blot (WB) analysis of CSF samples for detection of anti-Sarcocystis neurona antibodies, and on CSF albumin and IgG concentrations, albumin quotient (AQ), and IgG index in horses. DESIGN: Prospective in vitro study. SAMPLES: Blood with various degrees of immunoreactivity against S neurona was collected from 12 healthy horses. Cerebrospinal fluid without immunoreactivity against S neurona was harvested from 4 recently euthanatized horses. PROCEDURE: Blood was serially diluted with pooled nonimmunoreactive CSF so that final dilutions corresponded to 10(-3) to 100 microliters of blood/ml CSF, and WB analysis was performed on contaminated CSF samples. Number of RBC, albumin and IgG concentrations, AQ, and IgG index were also determined. RESULTS: Antibodies against S neurona were detected in CSF contaminated with 10(-3) microliters of strongly immunoreactive blood/ml. In CSF samples contaminated with 10 microliters of blood/ml, AQ remained within reference range. Volume of blood required to increase IgG index varied among blood samples and was primarily influenced by serum IgG concentrations. Number of RBC in contaminated samples was correlated with volume of blood added, but not with degree of immunoreactivity detected in contaminated CSF samples. CONCLUSIONS AND CLINICAL RELEVANCE: During collection of CSF from horses, contamination with blood may introduce serum antibodies against S neurona at concentrations sufficient for detection by WB analysis, thus yielding false-positive results. When blood is moderately or strongly immunoreactive, the amount of contaminating albumin may be small enough as to not increase AQ above reference range. In these cases, AQ and IgG index should be interpreted with caution.

Albumins↗
PubMed1999

Structure and evolution of the extended B7 family.

Here, Joëlle Henry and colleagues explore structural and evolutionary relationships between the B7 costimulator molecules and a growing number of molecules encoded within the major histocompatibility complex. They propose that B7 and MHC genes are derived from a common ancestor, with several members of this large gene family possibly having pivotal influences on T-cell activation.

Amino Acid Sequence↗
PubMed1999

Estrogen modulates spontaneous alternation and the cholinergic phenotype in the basal forebrain.

We report that a small population of neurons expresses both choline acetyltransferase and classical estrogen receptor immunoreactivity and they are found primarily in the bed nucleus of the stria terminalis. In short-term ovariectomized ageing mice (24 months, n = 5) there were 41.0 +/- 4.1% fewer of these double-labeled cells than in young (five months, n = 5) short-term ovariectomized C57BL/6J mice. To study cholinergic neuron estrogen responsiveness, young mice (n = 8) were ovariectomized at puberty (five weeks). After three months half of the mice (n = 4) were given physiological levels of 17beta estradiol for 10 days. Bed nucleus double-labeled neurons increased by 32.9% (P < or = 0.003) in the young mice given estrogen. In a gel shift assay, double-stranded oligonucleotides with putative estrogen response elements from the choline acetyltransferase gene were used as competitors against estrogen receptor binding to consensus estrogen response elements. A sequence with 60% homology to the vitellogenin estrogen response element was found to compete at 500- and 1000-fold excess. Young mice (five months) with ovaries demonstrated significantly (P < or = 0.04) better performance in the spontaneous alternation T-maze test than did old (19 month) mice with ovaries (young = 66.3 +/- 3.3% correct choices; vs old = 55.0 +/- 4.0% in old mice with ovaries). Young mice (five months old), ovariectomized for one month and treated with estrogen, showed significantly more spontaneous alternation than ovariectomized controls (69.1 +/- 2.8% vs 58.3 +/- 3.9%; P < or = 0.04). Estrogen also increased spontaneous alternation in old, short-term ovariectomized mice (61.5 +/- 2.7% vs 48 +/- 3.3%; P < or = 0.005). In either young or old ovariectomized mice, estrogen increased spontaneous alternation to levels seen in young animals with ovaries. Estrogen increases the number of choline acetyltransferase-immunoreactive and choline acetyltransferase/estrogen receptor-immunoreactive cells in old or young mice lacking estrogen, and enhances working memory in old or young mice lacking estrogen. Our data suggest that estrogen may act at the level of the choline acetyltransferase gene, but in view of the limited distribution of cholinergic cells expressing the classical estrogen receptor, it is unlikely that these cells can account for a memory enhancing effect of estrogen replacement.

Aging↗
PubMed1999

Theoretical basis for the benefit of postmenopausal estrogen substitution.

Women are being presented with an increasing number of choices for health care management as they move through the aging process. Estrogen has positive effects on mood, sexual function, target end organs and cognitive function, and may play an important role in the etiology of Alzheimer's Disease by acting to prevent amyloid plaque formation, oxidative stress, or deterioration of the cholinergic neurotransmitter system. The benefits of estrogen therapy for osteoporosis, the cardiovascular system, and lipid metabolism are far reaching, but the possibility of developing breast cancer later in life is also relevant. Understanding the mechanisms for the action of the estrogens, anti-estrogens, and the selective estrogen receptor modulators, and possible alternative routes of symptom management for some menopausal events is important to make appropriate decisions on choice of therapy. This review discusses the theoretical basis for estrogen's actions in the management of the postmenopausal stage of the life cycle.

Alzheimer Disease↗
PubMed1998

The formation of small-pore gels by an electrically charged agarose derivative.

Previous studies have shown that, during the formation of an underivatized agarose gel, agarose molecules laterally aggregate to form thicker fibers called suprafibers; the suprafibers branch to form a gelled network. In the present study, electron microscopy of thin sections is used to investigate both the thickness and the spacing of the fibers of gels formed by agarose chemically derivatized with carboxymethyl (negatively charged) groups. For carboxymethyl agarose, electron microscopy reveals that gels cast in water consist of both fibers narrower and pores smaller than those observed for water-cast underivatized agarose gels at the same concentration. This result is confirmed by using the electrophoretic sieving of spheres to determine the radius (PE) of the effective pore of the gel. At a given concentration of gel less than 1%, the PE for a water-cast carboxymethyl agarose gel is 0.25-0.30x the PE for a water-cast underivatized agarose gel. The value of PE predicts the extent of the electrophoretic sieving that is observed when double-stranded DNA is subjected to electrophoresis through a water-cast carboxymethyl agarose gel; DNA bands formed in a water-cast carboxymethyl agarose gel are comparable in quality to DNA bands formed in a water-cast underivatized agarose gel of equal PE. The following observation supports the hypothesis that electrical charge-charge repulsion among carboxymethyl agarose molecules inhibits the formation of suprafibers in water-cast carboxymethyl agarose gels: Increased content of suprafibers in carboxymethyl agarose gels is observed when the ionic strength is raised by the presence of NaCl, MgCl2, or any of several buffers during gelation of carboxymethyl agarose.

DNA↗
PubMed1998

The use of "diagnostic V codes" in pediatric ophthalmology.

BACKGROUND: Children requiring comprehensive eye examination for signs of familial eye disease or suspected systemic condition are referred to pediatric ophthalmologists. Such examinations may be critical to diagnosis and patient management, yet medically necessary screening examinations are not reimbursed by insurers when the patient is "normal." Faced with this dilemma regularly in a children's hospital practice, we began tracking insurer acceptance of "diagnostic V codes," which are diagnostic codes generally related to symptoms or status conditions rather than to medical states. The authors felt that "diagnostic V codes" might represent a more appropriate and correct code in the circumstance of a medically necessary screening examination found to be normal. METHODS: In July 1995 the use of 11 primary diagnostic V codes and 7 secondary diagnostic V codes was discussed in our faculty meeting and a list was displayed in each examination lane. Acceptance of V codes was then tracked for an 8-month period and analyzed 1 year later to provide a set of closed accounts. RESULTS: The code V71.8, or "observation for other specified, suspected condition" had a 73% acceptance rate by insurers on the basis of 207 examinations. The acceptance rate was not dependent on the use of a secondary code (76% for V71.8 alone vs 71% for secondary code used). Other V codes were infrequently used. CONCLUSIONS: The code V71.8 was an accepted code by insurers in our locality for medically necessary screening examinations found to be normal. The authors feel this high acceptance rate by insurers confirms our impression that V codes are the appropriate and correct codes to use for the medically necessary screening examination found to be normal.

Eye Diseases↗
PubMed1998

Formaldehyde in cryoprotectant propanediol and effect on mouse zygotes.

Cryopreservation of human zygotes and embryos has been routinely performed by in-vitro fertilization clinics for many years. Karran and Legge (1996) first reported that formaldehyde (FA) present in the cryoprotective solutions can have a deleterious effect on mouse oocytes. FA is a cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse zygotes was investigated. In addition, the concentrations of FA in propanediol (PROH) obtained from various sources were determined. Pooled 1-cell embryos were dispensed into droplets of modified Ham's F10 or human tubal fluid containing various concentrations of FA. Since bovine serum albumin (BSA) may minimize toxicity additional trials were done as above in the absence of BSA. FA concentration in the standard 1.5 M PROH, from different sources in water, was measured in the same assay using a standard curve of 0-100 microM FA. FA in a complex medium had a significant deleterious effect on embryo development and hatching but only at 1 mM concentration (P < 0.000001; see Tables I-III). There was no significant effect of FA at 100 microM. However, in a simple medium even 50 microM FA decreased embryo hatching. FA was present in 1.5 M PROH from different sources (range 1.0-35.3 microM concentration). It appears that FA concentrations do not increase with storage because FA concentrations were low even after opening and storage for 3 years on the shelf. This suggests that FA is a contaminant during the manufacturing process and may vary from manufacturer to manufacturer and batch to batch. Until further studies are done to confirm the lack of toxicity to embryos during cryopreservation (with or without FA scavengers) it may be prudent to screen all batches of cryoprotectants for FA as part of quality control.

Animals↗
PubMed1998

Out-of-body experience and personality functioning.

Reporters of out-of-body experiences (n = 21) and nonreporters (n = 159) showed no significant differences on the Spheres of Control Scale, Self-efficacy Scale, and Purpose in Life Scale. However, reporters of out-of-body experiences showed significantly greater belief in Psi, Spiritualism, and Extraordinary Life Forms than nonreporters.

Adult↗
PubMed1998

Assisted hatching of embryos by micromanipulation for human in vitro fertilization: UAMS experience.

In vitro fertilization and embryo transfer (IVF) is utilized as a treatment for infertile couples who cannot conceive with standard therapy. Assisted hatching (AH) is a procedure whereby an opening is made in the zona pellucida of the embryos, thereby increasing the probability of implantation and pregnancy. AH is beneficial in patients with elevated FSH levels, older than age 38 or those who failed IVF repeatedly. Success rates after IVF with AH at the University of Arkansas for Medical Sciences (UAMS) compares favorably with rates achieved by other centers in the USA. Pregnancy rates after IVF with AH in patients older than 38 years is approximately 20% compared to a pregnancy rate of 10% in patients who did not have AH. This report summarizes the UAMS experience with IVF and AH.

Adult↗
PubMed1998

Pagetic osteoclasts formed in vitro: absence of paracrystalline inclusions.

In Paget's disease of bone, osteoclasts are increased in number and size and contain intracellular paramyxoviral-like inclusions which cross-react with antibody against measles, respiratory syncytial, and canine distemper viral nucleocapsid antigens. Moreover, measles virus nucleocapsid transcripts are present in pagetic osteoclasts and their mononuclear precursors formed in vitro. The present study was undertaken to morphologically assess pagetic osteoclasts formed in culture; special attention has been directed towards the ultrastructural identification of nuclear and cytoplasmic inclusions. Pagetic osteoclasts were produced in long-term cultures of non-adherent bone marrow mononuclear cells derived from involved bone of patients with Paget's disease. These cultured osteoclasts had many of the ultrastructural features of pagetic osteoclasts in vivo. Of interest, no viral-like inclusions were observed in either the multinucleated osteoclasts or mononuclear cell precursors in these cultures. These data suggest that other factors in the bone microenvironment are required for viral nucleocapsid formation in pagetic osteoclasts.

Bone Marrow Cells↗
PubMed1997

Deleterious effect of equilibration temperature on the toxicity of propanediol during cryopreservation of mouse zygotes.

PURPOSE: Our aim was to determine the effect of temperature and incubation time on the toxicity of propanediol on mouse zygotes. METHOD: Zygotes were pooled and randomly allocated to one of the treatment groups. Zygotes were incubated in PBS or PBS containing 1.5M propanediol at 37 degrees C or room temperature (RT) for up to 30 min, washed, and cultured. Similarly, zygotes were incubated at 4 degrees C or RT for 30 min and either washed and cultured or frozen-thawed, washed, and cultured. Zygotes were examined at 24, 48, and 96 hr of culture and embryo quality was determined. RESULTS: Exposure of zygotes to 1.5 M propanediol at 37 degrees C significantly impaired first cleavage and blastocyst formation compared to exposure at RT (P < 0.0007). Incubation of zygotes for more than 5 min at 37 degrees C significantly reduced embryo development (P < 0.00001). Exposure to propanediol at 4 degrees C results in similar embryo development before and after freeze-thawing compared to exposure at RT. CONCLUSIONS: Propanediol is toxic to mouse zygotes in a temperature- and time-dependent fashion. Cryopreservation of zygotes after exposure at 4 degrees C appears to be no better than after exposure at RT.

Animals↗
PubMed1997

Bilateral internal jugular venous thrombosis complicating severe ovarian hyperstimulation syndrome after prophylactic albumin administration.

OBJECTIVE: To report a case of bilateral thrombosis of the internal jugular veins in a patient after controlled ovarian hyperstimulation and IVF. DESIGN: Case report. SETTING: University-based IVF program. INTERVENTION(S): Ovulation induction with gonadotropins, IVF-ET, albumin administration, and therapeutic heparinization. MAIN OUTCOME MEASURE(S): Doppler ultrasound of neck veins. RESULT(S): Severe ovarian hyperstimulation syndrome and bilateral thrombosis of the internal jugular veins occurred despite prophylactic administration of albumin. This was treated successfully with therapeutic heparinization. CONCLUSION(S): Internal jugular venous thrombosis, a rare complication of ovulation induction with gonadotropins, should be considered in patients with neck pain and swelling.

Adult↗
PubMed1997

Equine degenerative myeloencephalopathy.

EDM is a neurologic disease of young horses characterized by the insidious development of symmetric ataxia. Decreased or absent cutaneous trunci reflex or slap test responses are considered clinical signs that increase the index of suspicion for this disease. In addition, concurrent predisposing factors, such as familial history, inadequate access to green pasture, and possible exposure to wood preservatives or insecticides, provide further supporting evidence for a clinical diagnosis. Vitamin E deficiency and a hereditary predisposition currently are considered the most significant factors in the pathogenesis of this disease. Histopathologically the lesions of EDM are those of neuraxonal dystrophy, characterized by prominent axonal and dendritic swelling, mild glial proliferation, and neuronal depletion and atrophy with lipofuscin-like pigment accumulation. Animals predisposed to EDM or with a clinical diagnosis of EDM should receive oral alpha-tocopherol acetate supplementation. Improvement in clinical signs may be seen following long-term treatment, but in general, the prognosis for complete recovery is poor.

Animals↗
PubMed1997

Barriers to hospice care: family physicians' perceptions.

The purpose of this study was to examine barriers family physicians face when providing hospice care. A questionnaire was developed by the authors, and was mailed to 1,013 randomly selected AAFP members. The questionnaire addressed the various hospice care barriers. The respondents felt comfortable with hospice care, but felt that they did not receive adequate education in this area. They stated that they do have access to hospice programs. There is a general belief on the part of the respondents that their education in death and dying issues, and in hospice care was inadequate. The respondents, however, did feel comfortable in providing hospice care.

Adult↗
PubMed1997

Absence of glucose decreases human fertilization and sperm movement characteristics in vitro.

The effect of glucose in a modified Ham's F10 medium (MM) without hypoxanthine, phosphate and transition metals on human fertilization and sperm survival in vitro was determined. Mature human oocytes from in-vitro fertilization (IVF) patients or Percoll-washed human spermatozoa were randomly allocated to one of the treatment groups: normal Ham's F10, MM, MM with 5 mM glucose (HGMM) and MM with 0.5 mM glucose (LGMM). Oocytes were inseminated in one of the four media for 12-20 h and checked for fertilization. Sperm were incubated likewise for 4 and 24 h, and sperm motility and sperm movement characteristics including average path velocity (VAP), curvilinear velocity (VCL), straight line velocity (VSL), amplitude of lateral head displacement (ALH), beat cross frequency (BCF), straightness (STR), and linearity (LIN) were determined using computer-assisted semen analysis. Fertilization rates were significantly lower in oocytes cultured in MM (23.8%) compared to LGMM (75.5%), HGMM (73.6%) or Ham's F10 (71.1%). Sperm characteristics after 4 h incubation in all four media were similar, except VAP, VSL, VCL and ALH were significantly lower in MM (no glucose) in comparison with the other three media. After 24 h VAP, VSL, VCL, ALH, LIN and percentage rapid spermatozoa were significantly higher in spermatozoa incubated in HGMM or Ham's F10 compared with MM or LGMM. Also after 24 h, the percentage of spermatozoa which were highly motile was greater in HGMM than in Ham's F10. Absence of glucose significantly lowered fertilization rates and sperm movement characteristics in vitro.

Culture Media↗
PubMed1997

Localization of Helicobacter pylori urease and heat shock protein in human gastric biopsies.

Helicobacter pylori is a spiral, gram-negative bacterium which causes chronic gastritis and plays a critical role in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori expresses significant urease activity which is an essential virulence factor. Since a significant fraction of urease activity is located on the surface of the bacterium, the urease molecule is a logical choice as an antigen for a vaccine; currently recombinant urease apoenzyme is being tested as a vaccine in phase II clinical trials. We have recently demonstrated that urease and HspB (a homolog of the GroEL heat shock protein) become associated with the surface of H. pylori in vitro in a novel manner: these cytoplasmic proteins are released by bacterial autolysis and become adsorbed to the surface of intact bacteria, reflecting the unique characteristics of the outer membrane. To determine if similar mechanisms are operative in vivo, we determined the ultrastructural locations of urease and HspB within bacteria present in human gastric biopsies. Our results demonstrate that both urease and HspB are located within the cytoplasm of all bacteria examined in human gastric biopsies. Interestingly, a significant proportion of the bacteria examined also possessed variable amounts of surface-associated urease and HspB antigen (from 5 to 50% of the total antigenic material), indicating that in vivo, H. pylori has surface characteristics which enable it to adsorb cytoplasmic proteins. This is consistent with our altruistic autolysis model in which H. pylori uses genetically programmed bacterial autolysis to release urease and other cytoplasmic proteins which are subsequently adsorbed onto the surface of neighboring viable bacteria. These observations have important implications regarding pathogenesis and development of vaccines for H. pylori.

Bacterial Proteins↗