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Biomedical subjects

R Leonard

Publications and source records attributed to R Leonard.

At least 19 recordsLinked to original sources
PubMed2001

Randomized, double-blind, placebo-controlled, multicenter trial of 6% miltefosine solution, a topical chemotherapy in cutaneous metastases from breast cancer.

PURPOSE: To compare 6% miltefosine solution (Miltex; Asta Medica, Frankfurt, Germany), a new topical cytostatic drug, with placebo as palliative treatment for cutaneous metastases from breast cancer. PATIENTS AND METHODS: In a double-blind, placebo-controlled, multicenter phase III study, a total of 52 patients with inoperable progressive skin lesions from histologically or cytologically confirmed breast cancer, not manageable by radiotherapy or systemic treatment, with superficial or flat skin lesions (estimated depth of invasion < or = 1 cm) were randomized to receive either 6% miltefosine solution or placebo. The solution was applied at the dose of 2 drops/10 cm(2), once daily during the first week and twice daily thereafter until treatment failure. RESULTS: Treatment groups were well balanced for patient characteristics at study entry except for a small difference in age. Time to treatment failure (TTF), the primary parameter of this study, showed miltefosine solution to be significantly superior to placebo (P = .007); the median TTF in the miltefosine solution group was nearly three times longer than that in the placebo group (56 days v 21 days). The rate of response based on intention to treat patients was 33.3% for miltefosine solution compared with 3.7% for placebo (P = .006). Cutaneous reactions were seen mainly in the miltefosine group, with the type and frequency similar to those observed in previous studies. CONCLUSION: 6% Miltefosine solution is confirmed as an effective palliative treatment option for cutaneous metastases from breast cancer. Skin reactions, when present, are well tolerated and only occasionally require cessation of treatment.

Administration, Topical↗
PubMed2001

Phonoscopy--a valuable tool for otolaryngologists and speech-language pathologists in the management of dysphonic patients.

OBJECTIVES: To describe the phonoscopic evaluation, present a rationale for its use, and demonstrate its use in identifying laryngeal and vocal pathology. STUDY DESIGN: Retrospective review. METHODS: One hundred consecutive cases of new patients referred to our voice clinic team were reviewed. Findings on laryngeal examination as reported by the referring otolaryngologist were compared with our findings on "phonoscopic" examination. The phonoscopic examination combines the traditional voice evaluation performed by speech-language pathologists with endoscopy, which is relatively new to the voice clinician, to visualize the larynx during a broad sample of phonatory tasks. Patients with spasmodic dysphonia or tremor were excluded from the study. RESULTS: In 26 cases of the 100 reviewed, our observations were consistent with those of the referring otolaryngologist. In 32 cases, we agreed with the referral diagnosis, but found additional factor(s) related to pathology. In 42 cases, our findings differed from those of the referring physician. CONCLUSIONS: Results support our contention that phonoscopic evaluation can be of value to both the otolaryngologist and speech-language pathologist. It is particularly recommended in those patients whose dysphonia is unexplained following diagnostic laryngeal examination by the otolaryngologist, in cases in which voice use is a suspected factor in the pathology, and when voice therapy is a recommended treatment for a dysphonic patient.

Diagnosis, Differential↗
PubMed2001

Growth hormone secretagogue receptor family members and ligands.

We have previously reported the cloning and characterization of a new orphan G-protein-coupled receptor (GPC-R), the growth hormone secretagogue receptor (GHS-R), and shown that this receptor mediates the activity of the growth hormone-releasing peptides (GHRPs) and nonpeptide ligands such as L-692,429 and MK-0677. Because the GHS-R obviously does not belong to any of the known GPC-R subfamilies, we searched for GHS-R family members by screening a human genomic library using low-stringency hybridization and screening a Pufferfish genomic library. The Pufferfish was selected because of its compact genome. From the human genomic library, a homolog, GPR38, with 52% identity to the GHS-R was isolated. From the Pufferfish library, three family members were isolated. The Pufferfish gene having 58% identity to the GHS-R, on expression in HEK293 cells, was activated with GHRP-6 and MK-0677. These results indicate that the GHS-R has been conserved for at least 400 million years and that the Pufferfish genome is appropriate for isolation of GHS-R family members. In our search for endogenous ligands for the orphan receptors GHS-R and GPR38, we showed that adenosine is a partial agonist of the GHS-R and that motilin is the endogenous ligand for GPR38. We also confirmed that the endogenous ligand ghrelin is a full agonist of the GHS-R.

Adenosine↗
PubMed2000

A community pseudo-outbreak of invasive Staphylococcus aureus infection.

Outbreaks of invasive infection caused by methicillin-susceptible and methicillin-resistant Staphylococcus aureus occur in hospitals, long term care institutions, and in patients discharged from these settings. In contrast, epidemic S. aureus infection has not been reported in well persons in the community. Here, we describe a group of healthy young adults who resided in the same neighborhood and participated together in school sports, and who developed serious S. aureus infections within 3 weeks of each other, suggesting a true community outbreak. Timely use of molecular epidemiological tools, however, demonstrated that their illnesses were caused by unrelated bacterial strains.

Adolescent↗
PubMed1999

Imaging features of leptomeningeal metastases.

AIMS: To assess the range of appearances, and accuracy of various methods of diagnosing leptomeningeal metastases. MATERIALS AND METHODS: In a retrospective study, the notes and imaging of all patients with a radiological and/or CSF cytological diagnosis of leptomeningeal metastasis (LM) were identified, and assessed for the following: age and sex, primary tumour type, presenting symptoms, initial radiological and cytological diagnosis, radiological appearances and length of survival following diagnosis. Discordance between the CSF cytology and radiological diagnosis of LM was also noted. RESULTS: 41 positive cases (36 female) of LM were identified over a 2.7 year period (diagnosis based on: imaging only--19 cases, cytology only--6, both--16 cases). The average age was 48 years, and the most frequent primary tumour was breast carcinoma (27/41). Two thirds of patients presented with at least one cranial or spinal nerve palsy. Where performed, contrast-enhanced CT was normal in 40% (10/25), with LM mistaken for parenchymal disease in a further 24% (6/25). CSF cytology was positive in 85% (22/26). Gadolinium-enhanced MRI was positive in all cases where it was performed (25/25). Pial enhancement and nodularity was the commonest finding (67%), but other manifestations included nodular disease, neural enhancement and white matter changes. Prognosis was uniformly poor. CONCLUSION: Leptomeningeal metastatic disease has a poor prognosis, and treatment regimen may differ from those of parenchymal CNS metastases. CT is normal or misleading in two thirds of patients, and CSF cytology may also be negative. Gadolinium-enhanced T1-weighted MRI complements CSF cytology, and is the investigation of choice in patients with a non-haematological primary tumour and suspected LM.

Adolescent↗
PubMed1999

Assessment of bone response to systemic therapy in an EORTC trial: preliminary experience with the use of collagen cross-link excretion. European Organization for Research and Treatment of Cancer.

This study was designed to evaluate new bone resorption and tumour markers as possible alternatives to serial plain radiographs for the assessment of response to treatment. Thirty-seven patients with newly diagnosed bone metastases from breast cancer, randomized to receive oral pamidronate or placebo tablets in addition to anticancer treatment within the context of a multicentre EORTC trial, who were both assessable for radiographic response in bone and had serum and urine samples collected for more than 1 month were studied. The markers of bone metabolism measured included urinary calcium (uCa), hydroxyproline (hyp), the N-telopeptide cross-links of type I collagen (NTx) and total alkaline phosphatase. The tumour markers measured were CA15-3 and cancer-associated serum antigen (CASA). Before treatment, levels of Ntx, uCa and Hyp were elevated in 41%, 24% and 28% respectively, and CA15-3 and CASA increased in 69% and 50%. For assessment of response and identification of progression, Ntx was the most useful bone marker. All markers behaved similarly in no change (NC) and partial response (PR) patients. There was a significant difference (P < or = 0.05) in Ntx levels (compared to baseline) at 1 and 4 months and in CA15-3/CASA at 4 months between patients with PR or NC and those with progressive disease (PD), and at 4 months between those with time to progression (TP) > 7 and those with TP < or = 7 months. The diagnostic efficiency (DE) for prediction of PD following a > 50% increase in Ntx or CA15-3 was 78% and 62% respectively. An algorithm to predict response to therapy has been developed for future prospective evaluation.

Adult↗
PubMed1999

Drug education: a review of British Government policy and evidence on effectiveness.

British Government policy on drugs primary prevention is outlined and principal recommendations are identified. The review is organized under the four main providers: police, teachers, peers and parents. Current methods are reviewed within a British policy framework with a focus on British programmes which have been evaluated. Most programmes use a combination of information, resistance or life skills training and normative education. Evaluative research suggests these methods are generally most effective. The police have achieved a community-wide approach, teachers have managed to integrate drug education into the National Curriculum, peer approaches have considered the needs of their target audience and parent approaches have recruited influential educators. However, more evaluative research is required before we can identify which particular programmes are most effective in reducing drug use.

Adolescent↗
PubMed1999

Differentiation of spasmodic and psychogenic dysphonias with phonoscopic evaluation.

OBJECTIVES: Identify laryngeal behaviors that differentiate patients with spasmodic dysphonia and patients with psychogenic dysphonia. STUDY DESIGN: Retrospective review of patients evaluated over a 3-year period with a diagnosis of either spasmodic or psychogenic dysphonia. Videotaped phonoscopic (laryngeal imaging) examinations of all noted aberrant behaviors were examined. Tally behaviors according to each subject group. METHODS: Three examiners unfamiliar with patients' previous diagnoses reviewed videotaped studies. Aberrant behaviors were noted and each patient was assigned to spasmodic or psychogenic dysphonia group. Agreement among examiners and agreement with previous diagnoses was established. RESULTS: Six abnormal behaviors were noted, including tremor, hyperadduction, false fold constriction, sphincteric constriction, hyperabduction and paradoxical movements of the true and false folds. Percentage of patients in each group with each behavior was determined. CONCLUSIONS: Individual behaviors did not generally appear to differentiate the two groups; however, patterns of behaviors did, and may be of considerable value in differentiating spasmodic and psychogenic dysphonias.

Adult↗
PubMed1998

A hardware-software system for analysis of video images.

The purpose of this paper is to describe a software/hardware system for the analysis of digitized video images and a number of applications for which it may be used. The system described includes a Macintosh computer, a frame-grabber board, and Image, a public domain software program available at no cost from the U.S. National Institutes of Health. In our clinic and laboratory, this system is routinely used to make quantitative measurements from videofluoroscopic x-ray images of dynamic swallow studies and studies performed to assess velopharyngeal dysfunction in speech. It can also be used to examine various laryngeal parameters obtained from videotaped endoscopic and stroboscopic examinations. With a videocamera attached to a microscope, the system permits quantitative analysis of tissue characteristics, e.g., thickness of epithelial or connective tissue layers of the vocal folds. The relatively low cost and ease of use of the image analysis system make it a particularly attractive option when quantitative assessment of clinical or research materials in video format is desirable.

Computers↗
PubMed1998

Letrozole, a new oral aromatase inhibitor for advanced breast cancer: double-blind randomized trial showing a dose effect and improved efficacy and tolerability compared with megestrol acetate.

PURPOSE: To compare two doses of letrozole and megestrol acetate (MA) as second-line therapy in postmenopausal women with advanced breast cancer previously treated with antiestrogens. PATIENTS AND METHODS: Five hundred fifty-one patients with locally advanced, locoregionally recurrent or metastatic breast cancer were randomly assigned to receive letrozole 2.5 mg (n = 174), letrozole 0.5 mg (n = 188), or MA 160 mg (n = 189) once daily in a double-blind, multicenter trial. Data were analyzed for tumor response and safety variables up to 33 months of follow-up evaluation and for survival up to 45 months. RESULTS: Letrozole 2.5 mg produced a significantly higher overall objective response rate (24%) compared with MA (16%; logistic regression, P = .04) or letrozole 0.5 mg (13%; P = .004). Duration of objective response was significantly longer for letrozole 2.5 mg compared with MA (Cox regression, P = .02). Letrozole 2.5 mg was significantly superior to MA and letrozole 0.5 mg in time to treatment failure (P = .04 and P = .002, respectively). For time to progression, letrozole 2.5 mg was superior to letrozole 0.5 mg (P = .02), but not to MA (P = .07). There was a significant dose effect in overall survival in favor of letrozole 2.5 mg (P = .03) compared with letrozole 0.5 mg. Letrozole was significantly better tolerated than MA with respect to serious adverse experiences, discontinuation due to poor tolerability, cardiovascular side effects, and weight gain. CONCLUSION: The data show letrozole 2.5 mg once daily to be more effective and better tolerated than MA in the treatment of postmenopausal women with advanced breast cancer previously treated with antiestrogens.

Administration, Oral↗
PubMed1997

Initial frequency of alleles for resistance to Bacillus thuringiensis toxins in field populations of Heliothis virescens.

The risk of rapid pest adaptation to an insecticide is highly dependent on the initial frequency of resistance alleles in field populations. Because we have lacked empirical estimates of these frequencies, population-genetic models of resistance evolution have relied on a wide range of theoretical estimates. The recent commercialization of genetically engineered cotton that constitutively produces an insecticidal protein derived from the biocontrol agent, Bacillus thuringiensis (Bt) has raised concern that we lack data needed to quantify the risk of insect pests such as Heliothis virescens rapidly adapting to this ecologically valuable class of toxins. By individually mating over 2,000 male H. virescens moths collected in four states to females of a Bt toxin-resistant laboratory strain, and screening F1 and F2 offspring for tolerance of the toxic protein, we were able to directly estimate the field frequency of alleles for resistance as 1.5 x 10(-3). This high initial frequency underscores the need for caution in deploying transgenic cotton to control insect pests. Our single-pair mating technique greatly increases the efficiency of detecting recessive resistance alleles. Because alleles that decrease target site sensitivity to Bt toxins and other insecticides are often recessive, this technique could be useful in estimating resistance allele frequencies in other insects exposed to transgenic insecticidal crops or conventional insecticides.

Journal Article↗
PubMed1996

High-dose chemotherapy supported by peripheral blood progenitor cells in poor prognosis metastatic breast cancer--phase I/II study. Edinburgh Breast Group.

Current treatments for metastatic breast cancer are not associated with significant survival benefits despite response rates of over 50%. High-dose therapy with autologous bone marrow transplantation (ABMT) has been investigated, particularly in North America, and prolonged survival in up to 25% of women has been reported, but with a significant treatment-related mortality. However, in patients with haematological malignancies undergoing autologous transplantation, haematopoietic reconstruction is significantly quicker and mortality lower than with ABMT, when peripheral blood progenitor cells (PBPCs) are used. In 32 women with metastatic breast cancer, we investigated the feasibility of PBPC mobilisation with high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) after 12 weeks' infusional induction chemotherapy and the subsequent efficacy of the haematopoietic reconstitution after conditioning with melphalan and either etoposide or thiotepa. PBPC mobilisation was successful in 28/32 (88%) patients, and there was a rapid post-transplantation haematopoietic recovery: median time to neutrophils > 0.5 x 10(9) l-1 was 14 days and to platelets > 20 x 10(9) l-1 was 10 days. There was no procedure-related mortality, and the major morbidity was mucositis (WHO grade 3-4) in 18/32 patients (56%). In a patient group of which the majority had very poor prognostic features, the median survival from start of induction chemotherapy was 15 months. Thus, PBPC mobilisation and support of high-dose chemotherapy is feasible after infusional induction chemotherapy for patients with metastatic breast cancer, although the optimum drug combination has not yet been determined.

Adult↗
PubMed1996

Adhesion of calcium oxalate monohydrate crystals to anionic sites on the surface of renal epithelial cells.

Adhesion of microcrystals to the apical surface of renal tubular cells could be a critical step in the formation of kidney stones. The role of membrane surface charge as a determinant of the interaction between renal epithelial cells (BSC-1 line) and the most common crystal in kidney stones, calcium oxalate monohydrate (COM), was studied in a tissue culture model system. Adhesion of COM crystals to cells was blocked by cationized ferritin. Other cations that bind to cells including cetylpyridinium chloride and polylysine, as well as cationic dyes such as Alcian blue, also inhibited adhesion of COM crystals, but not all polycations shared this effect. Specific lectins including Triticum vulgaris (wheat germ agglutinin) blocked crystal binding to the cells. Furthermore, treatment of cells with neuraminidase inhibited binding of crystals. Therefore, anionic cell surface sialic acid residues appear to function as COM crystal receptors that can be blocked by specific cations or lectins. In vivo, alterations in the structure, function, quantity, or availability of these anionic cell surface molecules could lead to crystal retention and formation of renal calculi.

3T3 Cells↗
PubMed1996

Modulation of pulsatile GH release through a novel receptor in hypothalamus and pituitary gland.

Hormone replacement should provide a serum hormone profile similar to that found in normal physiology. This is generally impractical because hormones are usually released episodically and therefore require frequent administration. However, rather than replacing the hormone directly, in theory, one could administer a mimic or amplifier of the pulse generator that controls pulsatile release of the particular hormone. Using growth hormone (GH) as a paradigm we sought such a mimetic that would provide episodic GH release when administered by the oral route. A GH secretagogue MK0677, is described that has these ideal properties; following oral administration MK0677 amplifies episodic GH release. Mechanistically, it synergizes with growth hormone releasing hormone (GHRH) through a receptor and signal transduction pathway distinct from that of GHRH and is a functional antagonist of somatostatin (SRIF). MK0677 also acts on the arcuate nucleus and appears to stimulate GHRH release. By using 35S-MK0677, a new G-protein coupled receptor for MK0677 was characterized in the plasma membrane fraction of pituitary and hypothalamic tissue. The receptor is present in very low abundance and couples to phospholipase C. Other ligands selective for this receptor also cause synchronization of well-defined pathways leading to GH release. Repeated oral treatment of dogs once daily with MK0677 initiates amplified pulsatile GH release accompanied by increases in IGF-1 that are sustained. The unique biological properties of MK0677 and other synthetic ligands that bind to the same receptor force us to predict that these ligands mimic a naturally occurring hormone that regulates pulsatile GH release. Understanding the regulatory mechanisms involved in this paradigm has broad implications for the control of pulsatile rhythms in the endocrine system.

Amino Acid Sequence↗