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Biomedical subjects

M J Miller

Publications and source records attributed to M J Miller.

At least 163 records · Page 9Linked to original sources
PubMed1997

Expression of adrenomedullin and its receptor during embryogenesis suggests autocrine or paracrine modes of action.

The present study reports the developmental patterns of expression of adrenomedullin (AM) in rat and mouse embryos. AM is a novel multifunctional peptide recently isolated from a human pheochromocytoma, which has been shown to promote growth in a variety of mammalian cell lines. We have applied several techniques to investigate the localization of both the AM peptide and its receptor throughout development. Immunocytochemical detection has been performed using different specific antibodies against AM and its gene-related peptide pro-AM N-terminal 20 peptide. In situ hybridization showed the localization of the messenger RNAs for AM and its receptor. Western blot analysis together with reverse transcription-PCR gave further support to the localization of AM and its receptor in a variety of embryonic tissues. The localization of the receptor paralleled that of AM itself, suggesting an autocrine or paracrine mode of action. The spatio-temporal pattern of expression of AM in cardiovascular, neural, and skeletal-forming tissues as well as in the main embryonic internal organs is described. The primitive placenta, especially the giant trophoblastic cells, shows high levels of AM and AM receptor. The heart is the first organ that expresses AM during development. The kidney, lung, and developing tooth, in which epithelial-mesenchymal interactions are taking place, show specific patterns of AM expression. In several regions of the embryo, the patterns of AM expression correspond to the degree of differentiation. The possible involvement of AM in the control of embryonic invasion, proliferation, and differentiation is discussed.

Adrenomedullin↗
PubMed1997

Expression of adrenomedullin and its receptor in normal and malignant human skin: a potential pluripotent role in the integument.

Adrenomedullin (AM) is a multifunctional peptide involved in a variety of physiological functions, including growth regulation and antimicrobial activity. We have determined by immunohistochemistry and in situ hybridization that AM and its receptor are present in all the epithelial cells of the normal skin, including keratinocytes of the epidermis and hair follicles, as well as cells of the glands and secretory ducts. We also have detected AM in the sweat, by RIA. In addition, AM and its receptor were found in skin tumors of different histologies. The presence of AM and its receptor in normal and neoplastic skin was confirmed by RT-PCR and Western blot analysis performed on cell extracts from human skin cell lines. Radiolabeled AM bound to specific sites in cultured cells with a Kd of 9 nM. This binding was blocked by the addition of cold AM but not by related peptides such as AM 22-52, pro-AM 20 N-terminal peptide, calcitonin gene-related peptide, calcitonin gene-related peptide 8-37, or amylin. Finally, exposure to synthetic AM resulted in an increase of thymidine intake by skin cells. These results implicate AM as a potential player in skin defense against infectious microorganisms and as a possible autocrine growth factor in normal skin physiology and tumor development.

Adrenomedullin↗
PubMed1997

Adrenomedullin expression in the mouse mammary gland: evidence for the mature form in milk.

Adrenomedullin (AM) is a recently identified amidated peptide produced by a variety of tissue types. We have investigated the involvement of AM and its receptor (AM-R) in developing mouse mammary glands and have examined what influence ovarian hormones have on AM and AM-R expression in this system. Tissues from ductal morphogenesis, virgin adult, pregnancy, and lactation stages were assessed for AM and AM-R by molecular, biochemical and immunohistochemical techniques. Results from these studies indicated that messenger RNA for AM and AM-R and immunoreactivity for AM were expressed in the luminal epithelium of small and large ducts and in terminal end buds. Immunoreactive AM was identified as a cytoplasm component of ductal cells, with some cells also having nuclear staining. Western blot analysis of mammary gland tissues yielded two molecular mass species (M(r) 14,000 and 18,500) of AM immunoreactivity in the mammary gland for the above developmental stages, consistent with processed intermediate and prohormone forms respectively. Ovariectomy alone or followed by hormonal treatments did not alter the expression pattern for these two proteins. By Western blot, the fully processed AM form (M(r) 6000) was identified in milk extracts from lactating glands. These data suggest a potential role for AM and its receptor in the maintenance of mammary gland homeostasis and suggests a potential role for AM in development of the newborn.

Adrenomedullin↗
PubMed1997

Records of ectoparasites collected on ospreys from Ontario.

Ectoparasites were collected from ospreys (Pandion haliaetus) in four study areas within the Great Lakes basin of Ontario, Canada. Two parasitic mite (Acari) species, Bonnetella fusca and Analloptes sp., were collected from nestlings. One chewing louse (Mallophaga) Kurodaia haliaeeti was collected from nestlings and adults. Prevalence and intensity of K. haliaeeti were greater in the most northern of the four study areas. Bonnetella prevalence and intensity did not seem to vary greatly across the study areas. New range and host records are presented for B. fusca and Analloptes sp., respectively.

Animals↗
PubMed1997

Anatomic relationship of the oculomotor nuclear complex and medial longitudinal fasciculus in the midbrain.

PURPOSE: To compare the MR characteristics of the oculomotor nucleus with its appearance on anatomic images. METHODS: Specimens of cadaveric brains were imaged in a 3.0-T MR imager equipped with a 3.0-cm solenoid coil. The specimens were sectioned, stained, and examined histologically. On anatomic sections, the oculomotor nuclei, medial longitudinal fasciculus, red nuclei, and oculomotor nerve were identified. The MR images were then compared with the anatomic sections. RESULTS: The oculomotor nuclei, medial longitudinal fasciculus, red nuclei, and oculomotor nerve could be identified on MR images by their size, shape, signal intensity, and location. CONCLUSION: MR images show the anatomic relationship of the oculomotor nerve complex, medial longitudinal fasciculus, and related structures in the brain stem.

Abducens Nerve↗
PubMed1997

The effect of inhibitors of inducible nitric oxide synthase on chronic colitis in the rhesus monkey.

GI inflammation is associated with an increase in nitric oxide production and expression of the inducible isoform of nitric oxide synthase (iNOS). Using a spontaneous model of chronic colonic inflammation in rhesus monkeys, which shares morphological and clinical features with ulcerative colitis, we assessed the therapeutic benefit of administration of iNOS inhibitors. Sixteen colitic rhesus monkeys underwent an endoscopy procedure before commencement of the trial, and biopsies from three sites of the colon and plasma were collected. Monkeys were randomly assigned to three treatment groups and were administered by oral bolus 60 mg/kg/day L-N 6-(1-Iminoethyl) lysine, 60 mg/kg/day aminoguanidine or a placebo (0.9% NaCl) twice daily. Monkeys were sacrificed after 10 days, coIonic tissue from multiple sites was dissected and processed for histological and biochemical analysis. In rhesus colitis, diarrhea was characterized by a significant increase in fecal water content and daily fecal output. iNOS was localized immunohistochemically in plasma cells and neutrophils in the colonic mucosa and lamina propria, paralleled by enhanced iNOS gene expression determined by reverse-transcriptase polymerase chain reaction. Only L-N 6-(1-iminoethyl) lysine administration resulted in a significant reduction in systemic nitric oxide production, and neither of the iNOS inhibitors significantly reduced the histological inflammatory score nor ameliorated diarrheal symptoms. From these findings, we conclude that in this chronic, spontaneous model of colonic inflammation, administering iNOS inhibitors with this treatment regimen did not provide any major therapeutic benefit.

Administration, Oral↗
PubMed1997

Comparison of nipple projection with the modified double-opposing tab and star flaps.

This study compared nipple projection after nipple reconstruction (following breast mound reconstruction) with either the modified double-opposing tab flap or the star flap. Areolar reconstruction and pigmentation of the nipple were achieved with tattooing. Nipple projection for 153 nipples was measured at least 6 months after the reconstruction, when projection was believed to have become stable. Mean follow-up was 2.27 years. In the 106 nipples reconstructed with modified double-opposing tab flaps, the mean projection was 2.4292 mm, while in the 47 nipples reconstructed with star flaps, the mean projection was 1.9681 mm (p = 0.021). We conclude that although both methods are effective, the modified double-opposing tab flap has slightly more projection after approximately 2 years. It is not known, however, whether this is because of reduced flap atrophy or longer initial projection by the modified double-opposing tab flap; further studies are ongoing.

Female↗
PubMed1997

Secondary deformities following mandibular reconstruction.

Restoration of secondary deformities following mandible reconstruction is a difficult challenge. Prevention is sometimes possible by careful planning, but frequently these problems are unavoidable. Thoughtful analysis of the deformity and individualized treatment planning are key ingredients of proper management.

Bone and Bones↗
PubMed1997

Microvascular reconstruction for cutaneous defects.

Advanced skin cancer of the head and neck is best managed by a multidisciplinary approach. The goal is to control the malignancy while maximizing function and aesthetics, and hence the quality of life, after therapy. As a member of the patient care team, the reconstructive surgeon brings specialized expertise in modern techniques of tissue transfer to provide the optimal restoration for patients following resection of the tumor. Microvascular surgery represents the current technical state of the art for reconstruction in these patients with advanced lesions.

Dermatologic Surgical Procedures↗
PubMed1997

The synthesis of enantiomerically pure, highly functionalized heterocycles: the products of amino acid based acylnitroso hetero Diels-Alder reactions.

The diastereoselectivities of several chiral acylnitroso dienophiles (9a-h, 12 and 15) derived from optically pure, N-protected alpha-amino hydroxamic acids (2a-h, 4 and 7) were determined in an intermolecular hetero Diels-Alder reaction with cyclopentadiene. The diastereomeric excesses ranged from 0 to 72%. Hydroxamic acids with polar functionality were examined extensively to determine the effect of hydrogen bonding on the cycloaddition. The largest increase in diastereoselectivity was observed with increasing the steric bulk at the alpha-position of the hydroxamic acids and not with potential hydrogen bonding interactions. The cycloadditions afforded synthetically useful quantities of functionally rich, enantiomerically pure heterocycles (10a-h, 11a-h, 13, 14, 16 and 17), which have been elaborated into a variety of biologically interesting products.

Amino Acids↗
PubMed1996

Inducible nitric oxide synthase and the regulation of central vessel caliber in the fetal rat.

BACKGROUND: The purpose of this study was to evaluate the possibility that inducible nitric oxide synthase (iNOS) regulates the fetal circulation. METHODS AND RESULTS: Positive evidence for iNOS gene expression was noted in heart central vessels and placenta of untreated rat fetuses. Rats in the last week of pregnancy were treated for 5 days with L-NG-(1-Iminoethyl)lysine (L-NIL), a selective inhibitor of iNOS, at 1, 10, and 100 micrograms/mL in the drinking water. To raise NO levels, lipopolysaccharide (LPS) 30 micrograms/kg was given by intraperitoneal injection, and sodium nitroprusside (SNP) was placed in mini-osmotic pumps to deliver 10 micrograms/kg per minute. Control animals were undisturbed. On day 21 of gestation, dams were anesthetized and fetuses were delivered by cesarean section and rapidly frozen in isopentane chilled in liquid nitrogen. Frozen sections (10 microns) were used to reconstruct a computer-generated three-dimensional image of the great vessels and ductus arteriosus. Significant constriction of the great vessels and ductus arteriosus was observed with L-NIL, whereas both LPS and SNP dilated these vessels. The vasorelaxant effect of LPS was blocked by L-NIL. NO release from placental explants was 633 +/- 41 nmol/L under basal conditions, increasing to 4.0 +/- 0.4 mumol/L with LPS administration, although placental iNOS message and protein levels were unchanged. CONCLUSIONS: We suggest that nitric oxide, generated by iNOS, plays a significant role in control of major vessel and ductus arteriosus caliber in the rat fetus. In regard to the nitrergic regulation of the circulation, the fetus is clearly different from the adult.

Animals↗
PubMed1996

Adrenomedullin expression in human tumor cell lines. Its potential role as an autocrine growth factor.

Although adrenomedullin (AM) previously has been identified in human tumors, its role has remained elusive. Analysis by reverse transcriptase-polymerase chain reaction (RT-PCR) revealed AM mRNA in 18 of 20 human normal tissues representing major organs, and 55 of 58 (95%) malignant cell lines. Western blot and high performance liquid chromatography analysis showed immunoreactive AM species of 18, 14, and 6 kDa that are consistent with the precursor, intermediate product, and active peptide, respectively. Immunohistochemistry and in situ RT-PCR performed on paraffin-embedded tumor cell lines of various tissue origins exhibited AM cytoplasmic staining. Neutralizing monoclonal antibody to AM inhibits tumor cell growth in a concentration-dependent manner, an effect that was reversed with the addition of exogenous AM. Responding tumor cells were shown to have approximately 50,000 AM receptors per cell by Scatchard analysis with 125I-AM and expressed AM receptor mRNA by RT-PCR. Our data showed 36 of 48 (75%) tumor cell lines expressed AM receptor mRNA by RT-PCR assessment, all of them also expressed AM. In the presence of AM, cAMP levels were shown to increase in tumor cells. Our collective data demonstrate that AM and AM receptor are expressed in numerous human cancer cell lines of diverse origin and constitute a potential autocrine growth mechanism that could drive neoplastic proliferation.

Adrenomedullin↗
PubMed1996

Inducible nitric oxide synthase, nitrotyrosine, and apoptosis in Helicobacter pylori gastritis: effect of antibiotics and antioxidants.

Helicobacter pylori infection is a known risk factor for gastric cancer. We hypothesized that H. pylori infection would lead to the sustained production of the reactive nitrogen species nitric oxide and peroxynitrite as part of the host immune response. We further hypothesized that H. pylori infection would lead to increased apoptosis of gastric epithelial cells, possibly in response to free radical-mediated DNA damage. Using immunohistochemistry, we stained and scored gastric antral biopsies from 84 Colombian patients with nonatrophic gastritis before and after treatment for H. pylori infection. We examined expression of inducible nitric oxide synthase (iNOS); nitrotyrosine, a marker for peroxynitrite; and DNA fragmentation, a marker for apoptosis. Patients were treated with triple therapy (amoxicillin, 500 mg three times a day for 2 weeks; metronidazole, 400 mg three times a day for 2 weeks; and bismuth subsalicylate, 262 mg four times a day for 2 weeks, followed by 262 mg every day for 4-12 months). Eradication of H. pylori infection resulted in a significant reduction in iNOS and nitrotyrosine staining and a marginally significant reduction in apoptosis. Dietary supplementation with beta-carotene (30 mg every day for 4-12 months) resulted in a significant decrease in iNOS staining. Supplementation with ascorbic acid (1 g twice a day for 4-12 months) led to a significant reduction in nitrotyrosine staining. In patients supplemented with either ascorbic acid or beta-carotene, there was a trend toward a reduction in apoptosis, but this was not statistically significant. We conclude that H. pylori infection is accompanied by the formation of endogenous reactive nitrogen intermediates, which may contribute to DNA damage and apoptosis. In addition to antimicrobial therapy, dietary supplementation with beta-carotene and ascorbic acid may prevent the formation of these potential carcinogens.

Anti-Bacterial Agents↗
PubMed1996

Insulin-like growth factor expression in human cancer cell lines.

The insulin-like growth factors (IGFs), IGF-I and IGF-II, are potent mitogens for human lung and other epithelial cancer cell lines. Previous studies in defined medium lacking added IGF or insulin suggest that an IGF-related ligand can act as an autocrine growth factor for many cancer cell lines through action via the type I IGF receptor (IGF-R). Analysis of RNA isolated from human lung and breast cancer cell lines by reverse transcription of mRNA and polymerase chain reaction reveal that IGF-I and IGF-II mRNAs were co-expressed with IGF-R in the majority of cell lines. IGF-I mRNA was detected in 11/12 small cell lung cancer cell lines (SCLC), 13/14 nonsmall cell lung cancer (NSCLC) cell lines, and 1/2 breast cancer cell lines. IGF-II mRNA was detected in 8/10 SCLC, 11/12 NSCLC cell lines, and 2/2 breast lines. All cell lines expressed IGF-R. For analysis of IGF peptide secretion, cell lines were adapted to growth in serum/hormone-free culture medium (R0), and to avoid interference by IGF-binding proteins, secreted IGF peptides were isolated under acidic conditions and analyzed by Western blotting. Based upon measurement of the sensitivity of the anti-IGF antibodies for detection of recombinant human IGFs, IGF peptides accumulated in conditioned medium at greater than picomolar concentrations should have been readily detected. In three cell lines (two lung and one breast) secreted IGF immunoreactivity was detected as three molecular mass species of 23, 14, and 6 kDa. Isolation and NH2-terminal sequencing of each of these species definitively identified them as differentially processed forms of the IGF-II prohormone. Despite the high frequency of IGF-I gene expression detected by reverse transcription-polymerase chain reaction analysis, only one lung cancer cell line, NCI-N417d, was found that unequivocally secreted IGF-I peptide. This direct sequence determination unambiguously identifies IGF-II as the predominant IGF involved in the autocrine growth stimulation of human lung and breast epithelial tumor cell lines and supports a growing body of literature that implicates IGF-II/IGF-R autocrine loops as a common growth mechanism in epithelial carcinogenesis.

Adenocarcinoma↗
PubMed1996

Plasma GABA predicts acute response to divalproex in mania.

Bipolar I, manic phase inpatients were treated with divalproex sodium, lithium, or placebo in a previously reported parallel group multicenter, double-blind, randomized, controlled acute phase treatment trial. Plasma concentrations of gamma aminobutyric acid (GABA) were measured before and after treatment. Higher pretreatment plasma GABA levels were significantly (p = .04) related to a better clinical response to divalproex (n = 19). Pretreatment plasma GABA levels did not correlate with response to either lithium (n = 13) or placebo (n = 31). Following treatment with divalproex sodium, plasma GABA levels decreased significantly (p < .05), compared to placebo. Pretreatment plasma GABA levels were not related to overall severity of manic symptoms. Plasma GABA may predict response to pharmacologic agents acting on the GABA system.

Adult↗
PubMed1996

Lesion-directed administration of alteplase with intracoronary heparin in patients with unstable angina and coronary thrombus undergoing angioplasty.

Percutaneous coronary revascularization in patients with unstable angina and coronary thrombus carries a high complication rate. A new strategy to reduce thrombus burden before revascularization was tested in a multicenter prospective trial. Patients with unstable angina and coronary thrombus (n = 45) received alteplase through an infusion catheter at the proximal aspect of the target lesion and concomitant intracoronary heparin via a standard guiding catheter. Angiography was performed before and alter lesion-directed therapy and post-intervention. Systemic fibrinogen depletion and thrombin activation were not observed, while fibrinolysis was evident for > or = 4 hr after treatment. Target lesion stenosis did not change significantly after lesion-directed therapy, but thrombus score was reduced, particularly among patients who had large thrombi (mean 2.2 vs. 1.6, P = 0.02). Revascularization was successful in 89% of patients. Median final stenosis was 30% and mean final thrombus score was 0.4. Complications included recurrent ischemia (11%), MI (7%), abrupt closure (7%), severe bleeding (4%), and repeat emergency angioplasty (2%). Patients with overt thrombus appeared to derive the most angiographic benefit from lesion-directed alteplase plus intracoronary heparin. Later revascularization was highly successful. This strategy may be a useful adjunct to percutaneous revascularization for patients with unstable angina and frank intracoronary thrombus.

Adult↗
PubMed1996

Trypanosoma cruzi: protective immunity in mice immunized with paraflagellar rod proteins is associated with a T-helper type 1 response.

We have examined the ability of mice to survive a lethal challenge with the parasitic hemoflagellate, Trypanosoma cruzi, following immunization with paraflagellar rod proteins (PAR) 1 and 2 either alone or in combination with the following adjuvants: Freund's, alum, QS-21, Ribi-700, or IL-12. PAR administered subcutaneously (sc) in combination with Freund's or alum provided significant protection, 100 and 83%, respectively, against a T. cruzi challenge. In contrast, PAR in combination with QS-21, Ribi-700, IL-12, or Freund's administered intraperitoneally (ip) or PAR alone provide no protection against a challenge. PAR-specific serum antibody titers and isotype profiles for several of the immunization regimens were determined, and no positive correlation could be seen between a protective immune response and either antibody titer or the subclass of antibody induced. We also examined the ability of PAR to stimulate T cells from the spleen and lymph nodes of mice immunized with PAR in combination with Freund's (sc), Freund's (ip), alum, or Ribi-700. Each of the adjuvants strongly enhanced the ability of enriched T cells to proliferate in a PAR-specific fashion, suggesting no obvious correlation between PAR-specific T cell activation and protection. However, examination of the cytokine profiles of the stimulated T cell groups showed that the protective groups differed from the nonprotective groups. While all four groups showed low levels of IL-10, the Freund's (sc) and alum groups had higher levels of IFN-gamma and IL-2 than Freund's (ip) and Ribi-700 groups, and most strikingly, no IL-4 could be detected in either the Freund's (sc) or the alum group, in contrast to significant levels of IL-4 in both the Freund's (ip) and the Ribi-700 group. These findings indicate that protective immunity in mice immunized with PAR is associated with a Th1-type response.

Adjuvants, Immunologic↗