ABSTRACT
In the first part of this paper we show how inverse problems for differential equations can be solved using the so-called collage method. Inverse problems can be solved by minimizing the collage distance in an appropriate metric space. We then provide several numerical examples in mathematical biology. We consider applications of this approach to the following areas: population dynamics, mRNA and protein concentration, bacteria and amoeba cells interaction, tumor growth.
Subject(s)
Mathematical Concepts , Models, Biological , Animals , Dictyostelium/growth & development , Dictyostelium/microbiology , Gene Expression Regulation , Humans , Neoplasms/pathology , Population Dynamics/statistics & numerical data , Pseudomonas aeruginosa/growth & development , Pseudomonas aeruginosa/pathogenicity , Stochastic ProcessesABSTRACT
McArdle's disease was diagnosed in a 38-year-old woman when exercise-induced rhabdomyolysis, which was accompanied by acute renal failure, was observed to occur. This is the only case that is known to us of acute renal failure due to rhabdomyolysis in a woman with McArdle's disease.
Subject(s)
Acute Kidney Injury/etiology , Glycogen Storage Disease Type V/complications , Adult , Female , Humans , Physical Exertion , Rhabdomyolysis/complicationsABSTRACT
A lipoadenoma of the parathyroid gland was discovered at autopsy as the result of a search for the cause of terminally detected hyperparathyroidism in an elderly man who had suffered cerebral infarction. It is the only case known to the authors in which this uncommon cause of hyperparathyroidism was found at post-mortem examination after hypercalcemia and raised levels of serum immunoreactive parathormone were documented during life.
Subject(s)
Adenoma/pathology , Hyperparathyroidism/etiology , Parathyroid Neoplasms/pathology , Adenoma/blood , Adenoma/complications , Adipose Tissue/pathology , Aged , Aged, 80 and over , Calcium/blood , Humans , Hyperparathyroidism/blood , Male , Parathyroid Hormone/blood , Parathyroid Neoplasms/blood , Parathyroid Neoplasms/complications , Phosphates/bloodABSTRACT
The accumulation of methylphenobarbital (MPB) and phenobarbital (PB) in plasma in two volunteers who were given continuous once-daily oral doses of MPB for 3 weeks was demonstrated by use of a selected ion-monitoring GC/MS assay. It was shown that the PB concentration exceeded the MPB concentration in plasma after about day 4, and that both barbiturates achieved plateau concentrations after about 2 weeks. GC/MS studies on the urine of these volunteers permitted the identification of several new metabolites of MPB. These included 5-ethyl-5-(4-hydroxyphenyl)-1-methylbarbituric acid (p-OH-MPB), and the 3-O-methylcatechols of both MPB and PB. The meta-isomers of hydroxy-MPB and hydroxy-PB were identified in urine extracts, but were shown to be methodological artifacts. Quantitative studies, with use of a HPLC assay, were carried out for p-OH-MPB, PB and p-OH-PB in urine, and it was shown that these three substances collectively accounted for some 50% of the administered dose (greater than 30% as p-OH-MPB).
Subject(s)
Mephobarbital/metabolism , Phenobarbital/metabolism , Administration, Oral , Adult , Biotransformation , Gas Chromatography-Mass Spectrometry , Humans , Kinetics , Male , Mephobarbital/administration & dosageABSTRACT
The pharmacokinetics and bioavailability of mephobarbital have been studied in 2 volunteers. Plasma levels of mephobarbital and phenobarbital were measured by gas chromatography-mass spectroscopy with selected ion monitoring. Urinary output of phenobarbital and the p-hydroxy derivatives of both mephobarbital and phenobarbital was measured by high pressure liquid chromatography. The time course of these plasma and urinary levels was monitored following single 800-mg oral and 200-mg intravenous doses in the 2 patients. The major conclusions of the study were that mephobarbital is reasonably well absorbed following oral dosing and that some 35% or so of the dose (by either route) is converted to the recently identified metabolite, p-hydroxymephobarbital.
Subject(s)
Mephobarbital/metabolism , Administration, Oral , Adult , Biological Availability , Humans , Injections, Intravenous , Kinetics , Male , Mephobarbital/administration & dosageABSTRACT
A reversed-phase liquid chromatographic procedure was developed for simultaneous quantitation of three metabolites of the anticonvulsant methylphenobarbital in urine. These were p-hydroxyphenobarbital, phenobarbital, and p-hydroxymethylphenobarbital. Enzymatic hydrolysis was employed for liberation of the phenolic barbiturates from their glucuronide conjugates. Two internal standards were used at widely different concentrations, which conferred on the assay an accuracy over a wide concentration range. Concentration and instrument response (ultraviolet absorption at 215 nm) were linearly related over the concentration ranges of interest. The within-batch and between-day coefficients of variation were less than 4% in all cases. Recovery of all three analytes from the urine was nearly complete, and no substances that interfered with the assay were encountered in clinical specimens.
