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Biomedical subjects

M E Lund

Publications and source records attributed to M E Lund.

At least 19 recordsLinked to original sources
PubMed2001

Nutritional risk in an urban homebound older population. The nutrition and healthy aging project.

PURPOSE: To establish the prevalence of nutritional problems and their related socio-demographic and health-related risk factors in the homebound elderly population. METHODS: Subjects included 239 men and women, ages 65 to 105 years. Trained, two-person field teams conducted comprehensive in-home assessments. Medical record reviews assessed co-morbidity and medication use. RESULTS: The majority of these urban study subjects are of very advanced age (mean age 81 years), female (72%), non-white (73%), living alone (51%), of low income (76%), and somewhat socially isolated (26% had no weekly social contact). More older women than men were widowed (60 vs. 33%, respectively) and poor (80 vs. 67%). The disease burden and functional dependency were both high in men and women; 77% had three or more chronic medical conditions; 76% were functionally dependent in one or more ADL's and 95% in one or more IADL's. Poor dietary quality was universal in these older men and women; half or more consumed diets that deviated from recommended standards for at least 13 of the 24 nutritional guidelines studied. Five percent of subjects were underweight (Body Mass Index (BMI) <18.5); 22% were overweight (BMI 25.0-29.9); and 33% were obese (BMI >30.0). Fasting albumin, hemoglobin, and absolute lymphocyte concentrations were borderline to very low in 18-32%. Dyslipidemia was more common in women; however, men and women had similar Total:HDL cholesterol ratios. CONCLUSIONS: Nutritional status is poor in homebound persons of very advanced age with substantial co-morbidity and functional dependency. The complexities of nutritional risk necessitate multi-disciplinary and individualized nutritional intervention strategies.

Activities of Daily Living↗
PubMed2000

A surface plasmon resonance method for detecting multiple modes of DNA-ligand interactions.

A simple and general surface plasmon resonance (SPR) based method has been developed to detect and quantitate binding of low molecular weight compounds (200-1,200 Da) to double stranded DNA. Several compounds were chosen to probe three different modes of binding interactions, intercalation, minor groove binding and electrostatic interactions. Ethidium bromide (MW 390 Da), a probe of intercalative binding, was tested by plotting the steady state SPR responses measured on a DNA modified surface versus ethidium bromide concentration. The best fit of the binding isotherm gave a Keq of 1.8 x 105 M-1. Co-solvents such as DMSO are often used in activity assays to increase the solubility of poorly water-soluble drugs. The effect of DMSO on the ethidium bromide/DNA interaction was also tested by measuring binding in the presence of 0, 1 and 5%, DMSO. No effect on the measured Keq was observed at these DMSO concentrations. The binding of actinomycin (MW 1,255 Da), an antibiotic known to bind DNA through intercalation and minor groove binding, was also tested. The Keq estimated from the steady state responses on a DNA surface was 1.9 x 106 M-1. DAPI (MW 350 Da) (4',6-diamidino-2-phenylindole) a fluorescent probe which binds the minor groove of DNA was also tested and gave a Keq of 1.8 x 106 M-1 measured by SPR. Finally, spermine (MW 202) a compound known to bind DNA through ionic interactions gave the weakest Keq of 1.7 x 104 M-1. All the Keq values measured by SPR and reported for these compounds were in good agreement with literature values measured by other techniques.

Biotin↗
PubMed1997

Factors determining hydrogel permeability.

Developing hydrogel membranes and coatings of appropriate permeability characteristics is key to the success of a number bioartificial organ technologies. Key principles relevant to the design and application of hydrogels for such applications were reviewed. The first key point is that permeability is a function of both transport and thermodynamic properties, the diffusion coefficient and partition coefficient, respectively, and that these parameters can be evaluated separately. Although the aspect of partitioning often emphasized is size exclusion, this review points out that many other relevant interactions come into play, especially hydrophobic and electrostatic interactions, and that these phenomena can dominate size exclusion. Similarly, while the diffusion coefficient also is strongly dependent upon size, other interactions can also cause diffusivity to deviate from theories which consider only solute size and gel swelling. For example, the heterogeneity of hydrogel networks can result in permeabilities that fail to decline as much as might be anticipated if networks were uniform.

Animals↗
PubMed1992

Identification and characterization of an anti-isoaspartic acid monoclonal antibody.

The deamidation and rearrangement of protein-bound asparagine residues occurs when peptides and proteins are exposed to acidic or alkaline aqueous media. Asn99 of bovine growth hormone (bGH) is readily modified via these mechanisms. We have generated a monoclonal antibody (MAb) that interacts with a bGH fragment that contains an isoaspartyl residue. To obtain this antibody, CAF1/J mice were immunized with [isoaspartyl99]-bGH(96-112) conjugated to BSA. Using a competitive ELISA assay, the interaction of this MAb to [isoaspartyl99]-bGH(96-112) has been observed to have an apparent Km of 150 nM. The corresponding native peptide and other bGH fragments do not bind to this antibody with high affinity. For example, the binding affinities of [Asp99]-bGH(96-112) and [Glu99]-bGH(96-112) to this antibody are 54- and 78-fold lower than the corresponding isoaspartyl peptide. The antibody also binds to bGH that is enriched in isoaspartic acid at position 99, but not to the unmodified protein. The binding epitope of the peptide has been further characterized by comparing the binding of bGH(96-112) analogues to the MAb. Alanine substitution at residues 99, 100, 101, and 103 reduce binding affinity to the antibody by more than 10(3)-fold. Replacement of valine with alanine at position 102 has much less impact on antibody affinity. Further experiments suggest that the relative insensitivity to this substitution is due to the structural similarity of these sidechains. Other isoaspartic acid-containing peptides not derived from the bGH sequence do not bind to the antibody. We conclude that the epitope binding site of this MAb is highly specific for 99-103 of [isoaspartyl99]-bGH (96-112).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Treatment of acute methylmercury ingestion by hemodialysis with N-acetylcysteine (Mucomyst) infusion and 2,3-dimercaptopropane sulfonate.

A case of acute methylmercury ingestion was treated sequentially with oral D-penicillamine, hemodialysis during N-acetylcysteine (NAC) infusion, and 2,3-dimercaptopropane sulfonate (DMPS) an experimental oral agent. Urinary organic mercury elimination rate increased almost 40-fold during and 84-fold after hemodialysis with NAC infusion, compared with elimination during initial D-penicillamine therapy. Mean clearance during hemodialysis was only 13 ml/min with an extraction rate of 3.7 mcg/min. Although whole blood mercury concentrations decreased from 568 to 265 ng/ml during dialysis, a rebound to 525 ng/ml occurred. A total of 1.6 mg mercury was renally eliminated during hemodialysis and in the following 24 hours. A total of 3.3 mg of predominantly organic mercury was renally eliminated during 18 days of combined therapies. Since renal elimination of inorganic mercury is seen with chronic methylmercury poisoning, the high ratio of organic to inorganic mercury in urine supports the acute nature of this exposure. DMPS was begun on day 4 and during the two weeks of administration whole blood concentrations fell by 15% to 355 ng/ml. An expected decrease in elimination half-life to 10 days was not observed during DMPS therapy, possibly due to concurrent administration of vitamins containing zinc and copper. The amount of methylmercury ingested was estimated as 45 mg, based on a post-distribution blood concentration of approximately 450 ng/ml. The patient developed no symptoms of methylmercury poisoning during the one year after the episode. We conclude that NAC may be useful to enhance renal elimination of methylmercury and merits further investigation as a potential binding agent to reduce the body burden of methylmercury.

Acetylcysteine↗
PubMed1983

Failure of naloxone to reverse clonidine toxic effect.

Acute ingestions of imidazoline compounds, including clonidine hydrochloride, are a recognized clinical entity. The signs and symptoms of this overdose superficially resemble those of opiate intoxication, leading to attempts to reverse this poisoning with naloxone hydrochloride. Despite previous descriptions of success using naloxone in acute clonidine poisoning, five cases of acute pediatric ingestions of clonidine ranging from mild to severe occurred in which naloxone hydrochloride in doses up to 0.1 mg/kg was unsuccessful in reversing the signs and symptoms of this intoxicant. Although naloxone can be safely administered to children who ingest clonidine to distinguish them from those who are intoxicated by opiates, it is not therapeutically useful to use naloxone to reverse poisoning with this class of agents.

Bradycardia↗
PubMed1983

Evaluation of the Prompt inoculation system for preparation of standardized bacterial inocula.

Standardized inocula prepared with the 3M Prompt inoculation system were evaluated by (i) performing colony counts on the inocula and (ii) employing these inocula in disk diffusion or broth microdilution susceptibility tests. The inoculation wand delivered 1.85 X 10(8.0) +/- 0.6 log10 CFU to the various diluents tested. Inocula prepared in 1 ml of saline and used to inoculate disk diffusion tests resulted in 96.5% agreement between Prompt and standard tests when Prompt inocula were used within 15 min of preparation and 95.6% agreement between paired tests when Prompt inocula were allowed to sit at room temperature for 2 h before use. With 15-min Prompt inocula, only one (0.04%) major discrepancy between paired tests was observed. The 2-h Prompt inocula gave three (0.13%) major or very major discrepancies. The 15-min Prompt inocula prepared in 30 ml of diluent resulted in 98.2% of Prompt minimal inhibitory concentrations within +/- 1 log2 dilution step of the standard test result, whereas the 2-h inocula resulted in 97.4% agreement between paired minimal inhibitory concentrations at this level. Thus, the Prompt inocula were found to give results equivalent to those obtained from inocula prepared by conventional procedures.

Anti-Bacterial Agents↗
PubMed1983

Effect of alcohols and selected solvents on serum osmolality measurements.

The method by which serum osmolality is measured can significantly affect the result if certain volatiles or solvents are present in the specimen. Commonly available solvents and alcohols were added to aliquots of pooled human serum to produce toxicologically relevant concentrations. Increasing concentrations of carbon tetrachloride, chloroform, mono-n-butyl ether (butyl cellosolve), 1, 1,1 trichloroethylene, toluene, and xylene did not change vapor pressure (VP) or freezing point depression (FPD) osmolality. Acetone, ethanol, isopropanol, and methanol in increasing concentrations produced a linear increase in FPD osmolality, but no change in VP osmolality. Only ethylene glycol produced a linear increase in VP and FPD osmolality across the range of concentrations studied. Despite the excellent correlation between osmolality and ethanol concentration in prepared serum samples, this relationship could not accurately predict patient ethanol concentrations from FPD osmolality. The osmolal gap, "delta" osmolality, (measured FPD minus calculated osmolality) did not correlate with the difference between measured FPD and VP osmolalities. Patient ethanol levels could not be predicted with accuracy using an equation based on the osmolal gap or "delta" osmolality.

Blood↗
PubMed1979

Characterization of staphylococci using the API 20E system.

Fifty-four strains of coagulase-negative staphylococci, five isolates of coagulase-positive staphylococci, and seven species of Micrococcus were tested in the API 20E system. After 48 hours' incubation, results indicated that the various species and subgroups could be separated by their reactions. Staphylococcus saphrophyticus subgroup 3 was ONPG and mannitol positive. S. epidermidis subgroup 1 was positive for arginine dihydrolase (ADH), whereas S. epidermidis subgroup 4 was positive for ADH, mannitol, and arabinose. S. aureus coagulase negative was characterized by positive ONPG, ADH, and mannitol. In contrast, S. aureus coagulase positive was not positive for ONPG but was positive for ADH and mannitol. Most of these staphylococci were able to utilize nitrates, urea, glucose, and sucrose. The micrococci, on the other hand, gave varied reactions, with most species being only weakly reactive.

Bacteriological Techniques↗
PubMed1977

Rapid speciation of Haemophilus with the porphyrin production test versus the satellite test for X.

The detection of porphyrins produced from omega-aminolevulinic acid was evaluated for use in speciation of the Haemophilus. Two hundred and forty-eight clinical isolates of nonhemolytic Haemophilus were tested concurrently for porphyrin production and for X and V requirements. The porphyrin production test was more rapid (4 h) and more accurate than the satellite test.

Aminolevulinic Acid↗
PubMed1976

Significance of urinary isolates of coagulase-negative Micrococcaceae.

Of 16,347 urine cultures submitted to the hospital laboratory, 68 (0.4%) specimens from 50 patients yielded greater than 10(4) coagulase-negative staphylococci/ml in pure culture. A total of 62 of 63 organisms available for study were staphylococci: 45 Staphylococcus epidermidis (predominantly subgroup 1), 15 Staphylococcus saprophyticus (subgroup 3), and 2 Staphylococcus aureus. Twenty-one patients had "probable" urine infections. Eight patients had two or more positive urine cultures, and all isolates from the same patients were identical (by morphology, antibiotic susceptibility, and hemolytic pattern). Nine (75%) of the 12 isolates of S. saprophyticus, which were novobiocin resistant and nonhemolytic on the synergistic hemolysis test, were from patients with probable urinary infection. Eight were young women with acute symptoms and pyuria. Differences in the glucose and mannitol fermentation tests with different media may lead to difficulties in identification. Novobiocin resistance cannot be relied upon to differentiate isolates of S. saprophyticus from S. epidermidis.

Adolescent↗
PubMed1976

Inoculation of API-20E from positive blood cultures.

The API-20E system (Analytab Products, Inc., Plainview, N. Y.) was inoculated from 4- to 6-h tryptic soy broth cultures that had been inoculated from positive blood cultures containing gram-negative bacilli. This method gave the same genus and species identification for 139 of 140 organisms (47 patient and 96 simulated positive cultures) when compared to the Analytab Products, Inc., recommended method of inoculation.

Bacterial Infections↗
PubMed1975

Motility-indole-lysine-sulfide medium.

A medium designed for the detection of motility, indole, lysine decarboxylase and deaminase reactions, and H2S production was devised and evaluated. Results, using 157 strains of enteric pathogens, were in agreement with reference methods. When 300 isolates from fecal cultures were screened using this medium, Shigella was easily differentiated from Escherichia and more of the Proteus species, especially P. morganii, could be eliminated from further study.

Agar↗
PubMed1974

Biochemical and antibiotic susceptibility studies of H2S-negative Citrobacter.

Ninety-four strains of H(2)S-negative Citrobacter were biochemically characterized and their antibiograms were determined. The antibiograms demonstrated not only a difference from Enterobacter cloacae but also a difference within the Citrobacter group between the indole-negative and indole-positive strains. These differences were statistically significant and emphasize the importance of the indole reaction as an aid to speciation of the H(2)S-negative Citrobacter.

Anti-Bacterial Agents↗
PubMed1973

Rapid gentamicin bioassay using a multiple-antibiotic-resistant strain of Klebsiella pneumoniae.

A rapid bioassay for gentamicin levels in serum was developed by using a strain of Klebsiella pneumoniae that has multiple resistance to antibiotics. Assays were comparable when performed on either small or large petri plates, and results were available in 2 to 4 h. Studies showed an overall recovery of 97.6% for gentamicin alone or 104.5% in the presence of commonly used antibiotics. The procedure can be performed without the need to inactivate other antibiotics that may be present in the serum sample.

Biological Assay↗