Search PubMed⌕ Search

Biomedical subjects

M Mayo

Publications and source records attributed to M Mayo.

At least 37 records · Page 2Linked to original sources
PubMed1999

Phase II study of interferon-enhanced 131I-labeled high affinity CC49 monoclonal antibody therapy in patients with metastatic prostate cancer.

Adjuvant Interferon (IFN) was given to increase tumor antigen expression and enhance localization with 131I-labeled CC49 radioimmunotherapy in a Phase II trial for hormone resistant metastatic prostate cancer. Patients received four doses of alpha-IFN (3 x 10(6) IU) s.c. on alternate days, from day -5 to day +1 of 75 mCi/m2 131I-CC49 treatment. Toxicity was well tolerated, with the majority of patients experiencing transient grade 3 or 4 neutropenia and/or thrombocytopenia (maximal at 4-6 weeks). The absorbed dose was >25 Gy in four of eight tumors visualized, which represents an increase of >20 fold over whole body radiation dose. Two patients had radiographic minor responses by 6 weeks post-therapy, whereas five of six patients experiencing pain had symptom relief without radiographic changes. The protocol provided modest antitumor effects (pain relief in five of six patients and two minor radiographic responses). This study suggests that the addition of IFN enhanced tumor uptake and antitumor effects as compared to a prior Phase II trial of 131I-CC49 alone.

Aged↗
PubMed1998

Induced expression of myoD, myogenin and desmin during myoblast differentiation in embryonic mouse tongue development.

Significant progress has been made in defining mechanisms governing myogenesis at the transcriptional levels, but the extracellular signal-transduction pathways involved in myogenesis are not as yet defined. The developing mouse tongue provides a model for the regulation of myogenesis during precise time periods in embryogenesis. The molecular cues that regulate the close-range autocrine and/or paracrine signalling processes required for the fast-twitch complex tongue musculature are not known. This study was designed to test the hypothesis that transforming growth factor-alpha (TGF alpha) controls myogenesis in embryonic mouse tongue through the induction of myogenic regulatory factors such as myoD, myf5, myogenin and MRF4/myf6/herculin. To test this hypothesis, the effects of exogenous TGF alpha on the transcription of myoD, myf5, myogenin, MRF4 and desmin were examined in tongue samples from embryonic day-10.5 mandibular explants cultured in serum-free, chemically defined medium and then processed for competitive, reverse transcription-polymerase chain reaction. TGF alpha induced myoD, myogenin and desmin expression. Treatment with 20 and 40 ng/ml TGF alpha decreased or downregulated myf5 mRNA. MRF4 was not detected in the explants. TGF alpha apparently induces the early developmental stages of myogenesis through sequential upregulation of myoD and myogenin, downregulation of myf5 and corresponding significant increases in muscle-specific gene expression such as desmin transcription.

Analysis of Variance↗
PubMed1998

Simultaneous augmentation cystoplasty and artificial urinary sphincter placement: infection rates and voiding mechanisms.

PURPOSE: Simultaneous augmentation cystoplasty and artificial urinary sphincter placement have recently been reported to be associated with a high incidence of infection. We reviewed our results to define the infection rate and outline the mechanisms of voiding in our patient population. MATERIALS AND METHODS: A total of 29 patients underwent a simultaneous procedure. The etiology of lower urinary tract disease was exstrophy in 14 patients, myelomeningocele in 10, lipomeningocele in 3, spinal cord injury in 1 and radical retropubic prostatectomy in 1. We used 19 gastric, 5 ileal and 5 colonic intestinal segments. Average followup was 33 months. All patients were followed for a minimum of 2 years. Preoperatively all cases had mechanical bowel preparation and documented sterile urine cultures or treated bacteriuria. RESULTS: Infection developed in 2 patients (6.9%) necessitating artificial urinary sphincter removal at 1 week and 9 months. There were no infections associated with gastrocystoplasty. Clean intermittent catheterization was required in 21 patients, while the remaining 8 voided spontaneously. Of the 8 patients 4 were catheterized at least once daily to monitor residual urine volumes. Of all patients 5 were catheterized with a gastric tube, 5 with an appendicovesicostomy and 14 per urethra. CONCLUSIONS: A simultaneous procedure was associated with an acceptable prosthetic infection rate and gastric segments were associated with the lowest incidence of infection. The minority of patients voided spontaneously. The combination procedure was effective in achieving continence. However, in the future a nonprosthetic means of providing urethral resistance may provide better treatment.

Adolescent↗
PubMed1997

Characterization of the fate of midline epithelial cells during the fusion of mandibular prominences in vivo.

The fusion of the mandibular prominences along the midline is achieved with the absence of medial epithelial cells at the fusion site. Failure of fusion of the mandibular prominences results in median cleft of the lower lip and mandible. Cellular and molecular events controlling mandibular fusion were examined during the fusion process in mouse embryogenesis. Cell lineage analyses at the fusion site revealed that epithelial cells migrated to the surface and oral epithelia. DiI-labeled epithelial cells were not observed within the mandibular mesenchyme at any state of fusion. Examination of the midline region did not reveal cells with ultrastructural changes characteristic of apoptotic cell death. An increase in lysosomal enzymes in the midline epithelial cells, which would be correlated with programmed cell death, was not observed. Mice lacking TGF-beta 3 did not have cleft mandible, but had clefting of the secondary palate as a feature of null mutation phenotype. We interpret our comparisons between wild type and homozygous TGF-beta 3 (-/-) mice to suggest that different developmental processes control palatal vs. mandibular fusion. We hypothesize that medical epithelial cells at the fusion site of mandibular prominences migrate to the surface epithelium during the fusion process and neither transdifferentiate into mesenchyme nor express apoptosis.

Animals↗
PubMed1997

A prospective study of the impact of community-based azithromycin treatment of trachoma on carriage and resistance of Streptococcus pneumoniae.

In February 1995, single-dose azithromycin was given to children with trachoma and their household contacts who were children. For children with trachoma, rates of carriage of pneumococci immediately before treatment with azithromycin and 2-3 weeks, 2 months, and 6 months after treatment were 68% (54 of 79), 29% (11 of 38), 78% (29 of 37), and 87% (34 of 39), respectively. The proportion of carriage-positive children with azithromycin-resistant Streptococcus pneumoniae strains was 1 of 54 (1.9%) before treatment and then 6 of 11 (54.5%), 10 of 29 (34.5%), and 2 of 34 (5.9%) at follow-up visits. The profile of pneumococcal serotypes changed after azithromycin treatment. Azithromycin-resistant strains (serotypes 10F, 23A, and 45) were isolated from 1 (1.3%) of 79 pretreatment swab specimens, from 16 (21.3%) of 75 swab specimens collected up to 2 months after treatment, and from 2 (6%) of 32 obtained 6 months after treatment. Mathematical modeling showed a more rapid appearance of azithromycin-resistant pneumococcal strains in previously colonized children than in previously noncolonized children. Thus, it appears that the selective effect of azithromycin allowed the growth and transmission of preexisting azithromycin-resistant strains. More research is needed to clarify the clinical relevance and implications of azithromycin use.

Adolescent↗
PubMed1994

XX male syndrome in a cryptorchid stallion.

A bilateral cryptorchid stallion with mild development of mammary glands was identified as an XX male by karyotyping. Necropsy revealed underdeveloped accessory sex organs and hypoplastic, inguinally located testes that were deficient of spermatogonia. Evaluation of routine hormonal profiles (without karyotyping) would have failed to diagnose this syndrome.

Animals↗
PubMed1993

Properties of the satellite RNA of nepoviruses.

Satellite RNA depend for their multiplication on the co-infection of a host cell by a helper virus which can itself multiply independently of the satellite. Four types of satellite RNA have been distinguished on the basis of the size of the RNA and what sort, if any, of protein they encode. One of them, the B-type, comprises relatively large RNA which are messenger RNA for non-structural proteins. Many of these satellites are typified by having nepoviruses as helper viruses. In general, the presence of nepovirus mRNA satellites in a virus culture causes little or no modification to the symptoms of infection by the helper virus and has little effect on its yield. Some satellites appear to be highly specific to a strain of helper virus but others can be helped by heterologous viruses. The proteins encoded by nepovirus mRNA satellites have a M(r) of 38,000 to 48,000 and are relatively basic, in particular in the N-terminal and C-terminal parts of the molecules. However, there is little similarity in amino acid sequence between proteins encoded by different satellites and no peptide motif could be found in all satellite proteins. The results of reverse genetics experiments with satellites suggest that the satellite-encoded protein is essential for the multiplication of the satellite RNA. This system has considerable potential for the study of the mechanisms of replication both of satellite and helper virus RNA.

Amino Acid Sequence↗
PubMed1993

EGF abrogation-induced fusilli-form dysmorphogenesis of Meckel's cartilage during embryonic mouse mandibular morphogenesis in vitro.

Mutations associated with genes of the EGF superfamily are implicated in facial malformations arising from abnormal development of the first branchial arch. EGF and EGF receptor (EGFr) transcripts are expressed in the mouse embryonic first branchial arch and derivatives from E9 through E15. EGF transcripts are localized to ectomesenchymal cells associated with precartilage, cartilage, bone and tooth-forming cells. EGF and EGFr proteins co-localize to the same cells suggesting an autocrine regulation. To test whether EGF effects the timing and positional information required for Meckel's cartilage (MC) and tooth development, we cultured E10 mandibular explants in serumless, chemically defined medium with either antisense or sense EGF oligodeoxynucleotides. Antisense inhibition of EGF expression produces bilaterally symmetrical Fusilli-form dysmorphogenesis of MC and decreases tooth bud size; these effects are reversed by the addition of exogenous EGF to the culture medium. Tyrphostin RG 50864, which inhibits EGF receptor kinase activity, inhibits EGF stimulation of tyrosine phosphorylation in a concentration-dependent manner and severely retards mandibular development yet increases tooth size. These findings support the hypothesis that endogenous EGF and EGF-like proteins provide signalling to regulate the size and shape both of cartilage and tooth formation during craniofacial morphogenesis.

Animals↗
PubMed1992

Gene expression, signal transduction and tissue-specific biomineralization during mammalian tooth development.

Tooth development provides a paradigm for intrinsic molecular controls for cell- and extracellular matrix (ECM)-mediated biomineralization. The intent of this review is to evaluate the sequential timing and positional information prerequisite for tissue-specific biomineralization. Recent investigations suggest that 1,25-dihydroxyvitamin D3 functions to up-regulate VDR (vitamin D receptor) that in turn could induce structural gene products, including calcium-binding proteins and several ECM proteins (e.g., enamelins, amelogenins, dentine sialoglycoproteins (DSP) and dentine phosphoproteins (DPP)), resulting in dentine and enamel formation. Inhibition of regulatory gene products and/or their receptors likely results in hypoplastic and/or hypomineralized ECM as a direct consequence of down-regulated (1) transcription and/or translation of structural and regulatory genes, (2) posttranslational modifications, (3) and/or decreased calcium transport to the forming dentine and enamel matrices. Advances in serumless in vitro culture methodology; computer-assisted access to nucleic acid sequences for probes to define when, where, and how many specific regulatory and structural gene products are expressed; antisense oligodeoxynucleotides to inhibit specific translation; and microtechniques to analyze biomineralization all provide additional avenues to investigate tissue-specific biomineralization.

Animals↗
PubMed1991

Detection of anti-Ro(SSA) antibodies by gel double diffusion and a 'sandwich' ELISA in systemic and subacute cutaneous lupus erythematosus and Sjögren's syndrome.

A newly described Ro 'sandwich' ELISA was compared to the gel double diffusion technique to detect anti-Ro(SSA) antibodies in Sjögren's syndrome, systemic and subacute cutaneous lupus erythematosus patients. This study demonstrates that the ELISA assay increased the frequency of detection of anti-Ro(SSA) antibodies in these well defined connective tissue disease patients by approximately 5-10% compared to the gel double diffusion anti-Ro(SSA) antibody assay. The study also confirms that some patients make anti-Ro(SSA) antibodies directed solely at unique human Ro(SSA) antigen epitopes. We also detected the existence of a significant Sjögren's syndrome patient population failing to make significant anti-Ro(SSA) antibodies. We conclude from our study that the gel double-diffusion technique employing human spleen extract as a source of the Ro(SSA) antigen is, at present, the most cost-effective test to detect anti-Ro(SSA) antibodies.

Antibodies, Antinuclear↗
PubMed1991

Ectopic ureter: a rare cause of purulent vaginal discharge.

We report two cases in which urologic anomalies presented with vaginal discharge and fever in young women, aged 9 and 18 years. Both patients were ultimately diagnosed as having duplicated collecting systems with ectopic upper-pole ureters opening into the introitus. Although congenital urologic anomalies are a rare cause of vaginal discharge in young women, they should be included in the differential diagnosis of patients presenting with these symptoms.

Adolescent↗
PubMed1990

Cartilage, bone and tooth induction during early embryonic mouse mandibular morphogenesis using serumless, chemically-defined medium.

Studies were designed to test the hypothesis that plasma- and serum-deprived embryonic cells and tissues in vitro are capable of producing growth regulating factors which augment cartilage, bone and tooth induction during mouse mandibular process development. Embryonic mouse first branchial arch-derived mandibular processes (E11-E12, Theiler stages 18-19) or cap stage molar tooth (M1) organs (E15-E16, Theiler stage 23) expressed morphogenesis, histogenesis and cytodifferentiation (e.g., Meckel's cartilage and mandibular bone) when cultured as explants in permissive serumless and chemically-defined BGJB medium for periods up to 31 days in vitro. Organ cultures of early mandibular process explants in serumless conditions showed DNA synthesis comparable to the time- and position-restricted patterns characteristic for control in vivo development. As a paradigm for embryonic cell expression of putative growth factors, sense and antisense oligodeoxynucleotide probes corresponding to amino acids 1070-1081 for preproEGF, and antibodies directed against amino acids 348-691 of preproEGF, were used to identify and localize mRNA transcripts and translation products. Our preliminary evidence suggests that odontogenic epithelial and ectomesenchyme cells produce EGF-like products during instructive phases of tooth development. We suggest that plasma- and serum-deprived cells and tissues in vitro produce autocrine and/or paracrine growth factors which mediate embryonic mandibular morphogenesis, histogenesis and cytodifferentiation.

Animals↗