Martin Lowry

Martin Lowry
International Organisation for Succulent Plant Study

D.Phil.

About

79
Publications
20,922
Reads
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2,881
Citations
Citations since 2017
2 Research Items
771 Citations
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2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
Introduction
Martin Lowry used to work at the Centre for Magnetic Resonance Investigations, University of Hull but is now retired. Martin now does research on the distribution and taxonomy of Cactaceae in South America. His most recent publication is 'A synopsis of the genus Cleistocactus Lemaire (Cactaceae)'.
Additional affiliations
October 1991 - July 2015
University of Hull
Position
  • Lecturer
March 1985 - February 1987
The University of York
Position
  • PostDoc Position
February 1982 - February 1985
Memorial University of Newfoundland
Position
  • PostDoc Position

Publications

Publications (79)
Article
Full-text available
The history of the genus Cleistocactus Lem. (Cactaceae) is reviewed and significant eras outlined. A conservative species concept has been employed to group the over 300 published names into 24 species and 3 heterotypic subspecies. A complete synonymy is given for each of the accepted species along with an expanded description, distribution maps, e...
Article
Objectives: The aim of this study was to determine if associations exist between pretreatment dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI)-based metrics (vascular kinetics, texture, shape, size) and survival intervals. Furthermore, the aim of this study was to compare the prognostic value of DCE-MRI parameters against tradition...
Article
Full-text available
A high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plan...
Conference Paper
In order to derive brain haemodynamic parameters such as CBF and the residue function, DSC-MRI analysis typically involves a deconvolution problem. If the blood-brain barrier is disrupted, these parameters are artificially modified due to contrast agent (CA) leakage. In this work, a model free, non-parametric deconvolution method was modified (mCPI...
Article
To determine associations between dynamic contrast-enhanced MR imaging (DCE-MRI) parameters and survival intervals in patients with locally advanced breast cancer treated with neoadjuvant chemotherapy (NAC), surgery, and adjuvant therapies. Further, to compare the prognostic value of DCE-MRI parameters against traditional survival indicators. DCE-M...
Article
Full-text available
The taxonomic and nomenclatural history of Lobivia chrysochete (Werdermann) Wessner is reviewed and a lectotype established. Biogeographic, morphological and genetic information is provided to support the assertion that one member of the group, Lobivia chrysochete var. minutiflora Rausch, should be considered a distinct species. Illustrations of bo...
Article
Full-text available
The cacti of tribe Tephrocacteae (Cactaceae-Opuntioideae) are adapted to diverse climatic conditions over a wide area of the southern Andes and adjacent lowlands. They exhibit a range of life forms from geophytes and cushion-plants to dwarf shrubs, shrubs or small trees. To confirm or challenge previous morphology-based classifications and molecula...
Article
Full-text available
The results of an expedition to study some native species of cactus from west central Bolivia, in particular the east-facing slopes of the Cordillera Apolobamba and the Cordillera Real, and the first description of a new species, Echinopsis serpentina. Differences from related species are discussed along with notes on the habitat and known distribu...
Article
Branched-chain-amino-acid:α-ketoglutarate transaminase and branched-chain α-ketoacid dehydrogenase have been assayed in brains of control and of streptozotocin-induced diabetic rats. Enzyme activities were measured in five distinct regions of the brain: cerebellum, pons + medulla, midbrain, thalamus + hypothalamus, and telencephalon. Subcellular di...
Article
Full-text available
The ability to detect and identify malignant lesions within the prostate with conventional T2-weighted imaging is still limited. Although lesion conspicuity is improved with dynamic contrast-enhanced imaging there still remains some ambiguity as all tissues within the prostate may enhance. The aim of the current study was to take advantage of the i...
Article
Full-text available
To assess the use of a semiquantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to produce indices for enhancement curves that might enable differentiation between malignant prostatic lesions and normal peripheral zone (PZ). Fifty-two patients scheduled for radical prostatectomy underwent DCE-MRI before surgery...
Article
The purpose of this study was to investigate whether dynamic contrast enhanced MRI (DCE-MRI) data, both pharmacokinetic and empirical, can predict, prior to neoadjuvant chemotherapy, which patients are likely to have a shorter disease free survival (DFS) and overall survival (OS) interval following surgery. Traditional prognostic parameters were al...
Article
The aim of this study was to investigate the utility of the water T(2) values of malignant breast lesions in predicting response after the first and second cycles of neoadjuvant chemotherapy (NAC), both alone and in combination with lesion volumes. Thirty-five patients were scanned before the commencement of chemotherapy and again after the first,...
Article
Dopamine agonists (DA) may act on prolactinoma size and secretion through additional effects on adenoma vascularity that can be visualized using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). We hypothesized that DAs may exert their effect through a change in tumour functional vascularity leading to a reduction of prolactin (PRL) l...
Article
The quality of imaging obtained at high magnetic field strengths can be degraded by various artefacts due to conductive and dielectric effects, which leads to loss of signal. Various methods have been described and used to improve the quality of the image affected by such artefacts. In this article, we describe the construction and use of a simple...
Article
Octreotide causes significant tumour shrinkage in patients with acromegaly but the exact mechanism of action is unclear in vivo. To determine the mechanism of action of octreotide in vivo using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Five patients with acromegaly were treated with octreotide as primary medical therapy. DCE-M...
Article
Traditionally, tumor response has been assessed via tumor size measurements during the course of a treatment. However, changes in these morphologically based measures occur relatively late in the course of a treatment. Alternative biomarkers are currently being evaluated to enable an earlier assessment of treatment to facilitate early cessation and...
Article
A prospective study was undertaken in women undergoing neoadjuvant chemotherapy for locally advanced breast cancer in order to determine the ability of quantitative magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to predict ultimate tumour response (percentage decrease in volume) or to detect early response. Magnetic resonance imagin...
Article
Full-text available
A prospective study was undertaken in women undergoing neoadjuvant chemotherapy for locally advanced breast cancer in order to determine the ability of quantitative magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to predict ultimate tumour response (percentage decrease in volume) or to detect early response. Magnetic resonance imagin...
Article
Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) is an effective diagnostic modality for symptomatic breast disease. However, its role in evaluating clinically occult disease associated with mammographically detected microcalcification remains unclear. Women recalled following screening mammography with microcalcification had DCE-MRI...
Article
Full-text available
Neoadjuvant chemotherapy has become the standard treatment for patients with locally advanced breast cancer; however a technique that can accurately differentiate responders from non-responders at an early time point during treatment has still to be identified. The purpose of this work was to evaluate the ability of pharmacokinetically modelled dyn...
Article
The purpose of this work is to assess the additional benefit of MRI-based morphology and quantification of contrast enhancement in the differential diagnosis of sub-1cm breast lesions. Forty-three women with suspected breast cancer were examined using X-ray mammography, ultrasound mammography, and MRI. Dynamic contrast imaging was performed and rel...
Article
Full-text available
Change in tumour volume may be a relatively late manifestation of chemotherapy response in patients with inoperable breast cancer. Recent studies suggest that quantifying water apparent diffusion coefficient (ADC), microvessel permeability (Ktrans) or water to fat signal ratio (WFR), using magnetic resonance (MR) imaging or spectroscopy, may provid...
Article
It has been suggested that proton magnetic resonance spectroscopy (MRS) of the striatum can differentiate between parkinsonian syndromes. The present study aims to examine this claim by performing a systematic review of the existing literature. A MEDLINE search was performed between 1966 and October 1999, along with searches of conference abstracts...
Article
A study was undertaken to determine if the vascular characteristics measured by dynamic contrast-enhanced magnetic resonance imaging (primarily permeability surface area product and extracellular-extravascular tissue volume fraction) would be beneficial in explaining the inter-lesion metabolic heterogeneity displayed by human intracranial tumours....
Article
Six patients with idiopathic Parkinson's disease (IPD), six with clinically probable multiple system atrophy and six control subjects underwent quantitative proton magnetic resonance spectroscopy (MRS). The concentrations of the three major metabolites, N-acetylaspartate (NAA), creatine and choline, were quantified in the lentiform nucleus using ti...
Article
Full-text available
I introduce an unusual plant, presumed to be a natural hybrid, found growing near Yavi in northern Argentina and identify it as × Oreobivia nothgen. nov.
Article
The combined caudate head and anterior putamen of six patients with Huntington's disease (HD) was studied by quantitative magnetic resonance spectroscopy (MRS) and the spectra compared with those from a group of six age-matched normal subjects. The concentrations of the three major metabolites, choline, creatine and N-acetylaspartate (NAA), were qu...
Article
The lentiform nucleus of five patients with idiopathic Parkinson's disease (IPD) was studied by quantitative magnetic resonance spectroscopy (MRS), both before and after administration of apomorphine, and the spectra were compared with those from a group of age-matched normal subjects. The concentrations of the three major metabolites, choline, cre...
Article
We have previously reported a striking correlation between water T2 relaxation time and citrate concentration in the normal prostate (Liney G.P.; Lowry M.; Turnbull L.W.; Manton D.J.; Knowles A.J.; Blackband S.J.; Horsman A. Proton MR T2 maps correlate with the citrate concentration in the prostate. NMR Biomed. 9:59-64; 1996). In this study we pres...
Article
A commercial phased-array multicoil was used to acquire water-suppressed localized proton spectra of the two major anatomical regions of the prostate. The signal-to-noise ratio and spectral resolution allowed identification of peaks from choline and creatine, as well as a major peak from citrate. Quantification of the citrate peak using experimenta...
Article
A significant correlation between water T2 relaxation time and citrate concentration in the normal prostate is demonstrated using spatially localized spectroscopy and water T2 maps. These data imply that MR images may be used to infer the concentration of citrate at high spatial resolution. Preliminary results in patients demonstrate that this rela...
Article
Quantitative proton spectroscopic studies were performed on 39 volunteers and 16 patients with intracranial tumours. Estimates of T2 were obtained in white matter, grey matter, cerebellum, astrocytomas and meningiomas; T1 was determined in white matter only. White matter values of T2 for trimethylamines, creatine and N-acetyl aspartate (NAA) were 3...
Article
A multicentre trial of test objects and protocols for performance assessment in single volume and slice selective magnetic resonance spectroscopy (MRS) was conducted by the European Community Concerted Action on MRI and MRS. The trial assessed phosphorus and proton localisation techniques implemented on commercially available MR systems at ten site...
Article
Water-suppressed proton spectra of the two major anatomical regions of the normal prostate were acquired with a commercial phased-array multicoil. The spectra demonstrated excellent signal-to-noise ratio and spectral resolution allowing identification of peaks from choline, creatine, and amino acids, as well as a major peak from citrate. Quantifica...
Article
We studied six patients in the early stage of Huntington's disease, together with six unaffected normal subjects. Localized spectra were acquired from 4-ml voxels encompassing the combined putamen and caudate head using STEAM with TR=1 s and TE=40 ms. Metabolite concentrations were calculated using tissue water as an internal reference. Although MR...
Article
Quantitative proton spectroscopy was performed on 26 volunteers and 9 patients using STEAM. Voxels (8 ml) were localized within white matter or meningioma and water-suppressed spectra acquired with TR=2 s at three echo times. Concentrations were calculated using individual relaxation parameter values with tissue water as an internal reference. Comp...
Article
Full-text available
We have studied the metabolism of 31P-containing metabolites of post-menopausal breast cancers in vivo using magnetic resonance spectroscopy (MRS) and a 5.5 cm surface coil. Spectra were acquired from 23 diameter. The spectra of the 19 previously untreated tumours had significantly higher phosphomonoester (PME) 31P relative peak areas than the norm...
Article
Full-text available
We have studied the metabolism of compounds containing 31P in normal breast using magnetic resonance spectroscopy (MRS). Spectra were acquired from non-lactating pre-menopausal breast (n = 14 women), lactating breast (n = 8) and post-menopausal breast (n = 8). The standard acquisition protocol used a 5.5 cm surface coil with the volunteer prone to...
Article
The aims of this study were two-fold: to characterize the in vivo31P NMR spectrum of human breast tumours by identifying the metabolites contributing to each peak; and to demonstrate changes in the detectability of the phosphodiester (PDE) peak at varying field strengths. This was achieved by obtaining 31P spectra from 23 patients in vivo at 1.5 T...
Conference Paper
The authors describe the development of a model function that is appropriate to frequency domain signals associated with contaminated time domain data sets and they investigate the application of the simplex algorithm to the task of fitting the model function to the frequency domain data
Article
The purpose of this review is to examine the factors regulating ammonium production in the kidney and to place these factors in the perspective of acid-base balance. Renal ammonium production and excretion are required to maintain acid-base balance. However, only a portion of renal ammonium production is specifically stimulated by metabolic acidosi...
Article
The pathway of serine synthesis by the rat kidney has been investigated in vivo by measuring the net flux in the presence and absence of specific inhibitors of the glycine cleavage system, phosphoenol-pyruvate carboxykinase and gamma-glutamyltranspeptidase. In normal animals serine release was 705 +/- 187 nmol X min-1 X animal-1, whereas glycine up...
Article
Renal serine synthesis was studied in the isolated perfused kidney and in isolated cortical tubules. Serine was produced by the perfused kidney from both glycine and aspartate, indicating flux through at least two separate pathways: serine hydroxymethyltransferase and either the nonphosphorylated or phosphorylated intermediate pathways. The precise...
Article
The metabolism of hydroxyproline by the rat kidney leads to the production of significant quantities of both glycine and serine. This process was observed in both the isolated perfused kidney and in isolated cortical tubule suspensions. The rate of hydroxyproline metabolism was increased in both preparations by the addition of alanine. The distribu...
Article
Full-text available
Glycine is metabolized in isolated renal cortical tubules to stochiometric qualities of ammonia, CO2 and serine by the combined actions of the glycine-cleavage-enzyme complex and serine hydroxymethyltransferase. The rate of renal glycine metabolism by this route is increased in tubules from acidotic rats, but is not affected in vitro by decreasing...
Article
Full-text available
Isolated perfused rat kidneys removed considerable quantities of glycyltyrosine, glycylhydroxyproline, tetraglycine and prolylhydroxyproline from the perfusate. The component amino acids are released into the perfusate and, in the case of the glycine-containing peptides, there is increased synthesis of serine. Removal of peptides was more than coul...
Article
Metabolic rates and adenine nucleotide content of liver and kidney from hibernating ground squirrels were measured and compared to rats to study the biochemical adaptation to hibernation. High rates of renal and hepatic gluconeogenesis were observed in squirrels, particularly from propionate and glycerol compared to rat. During hibernation and star...
Chapter
The ability of true hibernators to ‘store’ their organs for long periods at temperatures of about 4°C may be one avenue worth exploring in an attempt to improve organ storage techniques.
Article
1. [31P]NMR spectra were obtained from a functioning isolated perfused rat kidney with the aim of determining intrarenal pH in acute acidosis. 2. Signals from intracellular inorganic phosphate could be observed in the absence of phosphate in the perfusion medium. Under these conditions renal ATP and inorganic phosphate content fell by 30% but total...
Chapter
In the kidney, a major function is the recovery of metabolites from filtered fluid or their excretion into the urine. Despite the many sophisticated techniques it has not been generally possible to establish the relationship between transport and metabolism, and transport of materials has often been studied without reference to the intracellular me...
Article
Full-text available
1. Activation by H+ and by Ca2+ of 2-oxoglutarate dehydrogenase extracted from mitochondria of normal or acidotic rat kidney is described. This effect, first shown for the enzyme from heart by McCormack & Denton [Biochem. J. (1979) 180, 533--544], is of a regulatory importance in kidney, in which organ, in contrast with heart, increased flux occurs...
Article
1.1. Phosphorus nuclear magnetic resonance (31P NMR) provides a non-destructive method for the quantitative observation of the most abundant phosphate-containing metabolites in isolated perfused kidney and in kidneys inside an anaesthetised animal.2.2. In this paper, the NMR method is introduced and the intracellular pH changes following acute rena...
Article
Full-text available
The ability of all eight D-aldohexose steroisomers to stimulate insulin release and biosynthesis was compared with their ability to serve as a metabolic substrate for isolated islets of Langerhans as judged by formation of lactate. Insulin release and synthesis were stimulated by glucose or mannose but not by allose, altrose, gulose, idose, galacto...
Article
Summary The ability of all eight D-aldohexose steroisomers to stimulate insulin release and biosynthesis was compared with their ability to serve as a metabolic substrate for isolated islets of Langerhans as judged by formation of lactate. Insulin release and synthesis were stimulated by glucose or mannose but not by allose, altrose, gulose, idose,...
Article
Full-text available
Rates of incorporation of [4,5-(3)H]leucine into insulin plus proinsulin, designated ;(pro)insulin', and total protein in rat pancreatic islets were measured. Glucose stimulates rates of total protein and (pro)insulin biosynthesis, but (pro)insulin biosynthesis is stimulated preferentially. Mannose and N-acetylglucosamine also stimulate (pro)insuli...

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