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Biomedical subjects

J Savory

Publications and source records attributed to J Savory.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Erythrocyte creatine in cord blood.

Erythrocyte creatine (EC) content and reticulocyte counts were compared in normal adults, pediatric patients with hemolytic anemia, and cord blood. A good correlation between reticulocyte count and EC content was found in normal subjects and patients with hemolysis, thus confirming the usefulness of creatine as an estimate of mean red cell age in these populations. No significant correlation (p greater than 0.1) was observed between the two measurements in cord blood. While reticulocyte counts were significantly elevated (p less than 0.001) in cord blood when compared to normal adults (indicating the presence of a young mean red cell age), EC concentrations in most samples were not correspondingly high. These results may indicate that creatine is not well synthesized by the neonatal red blood cell.

Adolescent↗
PubMedDate not supplied

Creatine kinase-MB activity: clinical and laboratory studies of specific immunochemical technique with optimized enzymatic assay.

A centrifugal analyzer method was developed for measuring the MB isoenzyme of creatine kinase (EC 2.7.3.2) in serum by use of a specific immunochemical technique that avoids interference from CK-BB and adenylate kinase. Enzymatic activity was measured kinetically at 30 degrees C with an optimized reagent containing creatine phosphate as substrate. The precision (CV) of the assay was 5 to 12 percent day-to-day (n = 39). The reference interval was 0 to 3.5 U per L (n = 45). Patient samples without detectable CK-MB in a widely-used electrophoretic assay contained up to 12 U per L of CK-MB by the new method. The new test was evaluated carefully in 99 patients consecutively admitted to the coronary care unit. Blood samples were obtained at frequent (four to eight hr) intervals. All patients with acute myocardial infarction (n = 27) had peak CK-MB greater than 7 U per L and greater than 3.5 percent of total CK. The predictive value of this result was 94 percent for the diagnosis of infarction. Abnormal results were documented at the same times (+/- four hr) following infarction by the electrophoretic and immunochemical techniques. Guidelines were evolved for interpreting the percent of MB (i.e., MB per total CK) at various time points. The test was reliable in documented early recurrent infarctions that occurred in three patients. The method appears to be an attractive alternative to electrophoretic techniques for use in diagnosis of acute myocardial infarction.

Adult↗
PubMedDate not supplied

Homogeneous enzyme immunoassay for theophylline with a centrifugal analyzer.

A rapid homogeneous enzyme immunoassay for theophylline has been adapted to a centrifugal analyzer. The sample volume used was 10 microliter and sera from as many as 28 patients could be measured in 180 seconds. The assay temperature was 30 degrees and the absorbance rates were measured at 340 nm. Within-run and run-to-run precision showed a coefficient of variation of less than 2.6 and 7.5 percent, respectively, for theophylline concentrations of 2.5 to 40 mg per liter. The method was linear to 50 mg per liter and the analytical recovery was quantitative. A comparison between high pressure liquid chromatography (X) and the centrifugal analyzer enzyme immunoassay method (Y) for 51 patient samples revealed a correlation coefficient of 0.976 with a regression line of Y = 1.07 X -1.05 mg per liter. Reagent costs were reduced three-fold by adapting the enzyme immunoassay procedure from a semi-automatic spectrophotometer to a centrifugal analyzer. An absorbance rate for each theophylline sample was obtained by a multipoint kinetic rate computer program by the centrifugal analyzer. Severe hemolysis and lipemia interfered in this assay.

Autoanalysis↗
PubMedDate not supplied

Biochemistry of renal failure.

The term uremia is used clinically to describe that state associated principally with the retention of nitrogenous metabolic products and is characterized by a raised blood urea concentration. The increase in the blood urea concentration is perhaps the most striking abnormality of the body fluids in renal failure, although it is not the most important functionally. The clinical syndrome of uremia involves all the systems of the body as a result of biochemical alterations in the constitution of the internal environment. The alterations in the latter compartment are due not only to the retained metabolic products but also to associated changes in water, electrolyte, and acid-base homeostasis. There are also features of the clinical syndrome of uremia which are attributable to variations in the rates of secretion and metabolism of a number of hormones in which the kidney is recognized to play a role, either directly or indirectly. This brief review deals with the retained uremic metabolites and their biochemical significance in the clinical syndrome of uremia. The metabolites discussed include urea, creatinine, guanidines and related compounds, uric acid, dimethylamine, and the middle molecule hypothesis. The potential role of some of these metabolites is discussed with regard to their potential toxic role as enzyme inhibitors. The biochemical aspects of uremic neuropathy are reviewed to highlight the biochemical complexity of the investigation of the uremic syndrome.

Creatinine↗
PubMedDate not supplied

Aluminum toxicity in relation to kidney disorders.

Aluminum toxicity in patients with chronic renal failure has been related to renal osteodystrophy and dialysis encephalopathy (DES). The toxicity is associated with renal osteodystrophy in two ways. One association is the iatrogenic effect of excessive use of aluminum hydroxide gels resulting in hypophosphatemia which interferes with bone mineralization. The second association may involve deposition of aluminum in bone owing to aluminum being absorbed during hemodialysis. Evidence for this second association has been gathered from epidemiological studies of hemodialysis centers and their practices of using either tap water high in aluminum in the dialysate, or aluminum-free deionized water. In patients with DES, aluminum accumulation in the brain has been clearly shown to come from either the ingestion of aluminum containing phosphate-binding gels, aluminum in the dialysate, or a combination of the two. The outbreak of the DES also has been well-correlated with the sudden elevation of aluminum in tap water owing to the use of large amounts of aluminum in water treatment plants. Whether aluminum itself or a combination of aluminum and other factors causes DES is not understood at this time.

Aluminum↗
PubMedDate not supplied

Disorders of calcium homeostasis in the fetus and neonate.

The physiological mechanisms involved in the alterations in calcium homeostasis during pregnancy are complex. The fetal acquisition of calcium, for skeletal growth, is obtained by an increase in intestinal calcium absorption in the mother with transplacental calcium transfer to the fetus. The regulation of calcium homeostasis during the transition from the intrauterine to the extrauterine environment is complex and poorly understood. Within the first few hours of life the serum calcium concentrations begins to fall progressively reaching a "trough" value by the second or third day of life and then increases to normal values by the tenth day of life. In some neonates the fall in calcium concentration is sufficient to be associated with either tetany or convulsions. Hypocalcemia is probably the commonest disturbance of calcium homeostasis that occurs in the neonate and can be subdivided into three main groups on the basis of the etiological mechanism involved. Other disorders of calcium homeostasis that may affect the neonate include hypoparathyroidism, either congenital or acquired, pseudohypoparathyroidism, and vitamin D deficiency. Hypercalcemia may occur, but is a relatively rare occurrence in the neonate.

Animals↗
PubMedDate not supplied

Aluminum distribution in serum following hemodialysis.

Aluminum is a toxic metal and has been implicated as the causative agent in the dialysis encephalopathy syndrome. In the study reported here, the transfer of aluminum to the blood from dialysis fluid during hemodialysis was demonstrated even when deionized water was used in the preparation of the dialysate. Studies were carried out on the binding of aluminum to serum proteins and other constituents in patients on long-term hemodialysis. Five major aluminum peaks were observed on chromatographic separation; four were associated with proteins and one large peak was probably associated with a low molecular weight species. The size of the latter peak was enhanced by increasing the aluminum content of the eluting buffer. It is postulated that this low molecular weight species might be the neurotoxic form of aluminum.

Aluminum↗
PubMedDate not supplied

Serum lactate dehydrogenase isoenzymes in the diagnosis of myocardial infarction.

The ratio of lactate dehydrogenase (LD-1:LD-2) in serum was studied in 101 patients admitted to a coronary care unit. The clinical reliability of the test could not be predicted from the normality or abnormality of the total serum lactate dehydrogenase (LD) activity. However, for samples with total LD activity below the middle of the normal range, no information was provided by the test. In contrast, the test provided reliable information when the total LD activity in the specimen was above the middle of the reference range (220 IU per L).

Electrophoresis↗
PubMedDate not supplied

Erythrocyte creatine levels in anemia.

The automated diacetyl-l-napthol procedure was found to be a simple and relatively quick method for the determination of erythrocyte creatine (EC), exhibiting both better precision and greater sensitivity than reticulocyte counting. A reference range of 1.8 to 5.0 mg per dl (mean, 3.0 +/- 0.9 mg per dl) was established by measuring EC levels in 81 normal adults varying in ages from 20 to 47 years of age. Normal creatine values displayed a slight sex dependency, with females exhibiting somewhat higher levels than males. In evaluating the relative usefulness of EC versus reticulocyte counting in the assessment of anemia, both parameters were measured and compared in 41 patients with various hemolytic and nonhemolytic anemias. A direct relationship was noted between the two parameters (p less than 0.0001); however, the actual data correlation was only fair (r = 0.49). In a serial study of an iron-deficiency anemic patient responding to iron administration, erythrocyte creatine levels were found to rise more slowly than the reticulocyte count and to remain elevated after the reticulocyte count had returned to normal.

Adult↗
PubMedDate not supplied

Lactic acid in cerebrospinal fluid: evaluation and application of an automated enzymatic assay.

The DuPont ACA lactic acid procedure was evaluated for use on cerebrospinal fluid (CSF). The method was linear to at least 13.9 mmol per L, day-to-day precision ranged from 3 to 9 percent (CV), and recovery of lactate added to cerebrospinal fluid averaged 104 percent. The method correlated closely with a centrifugal analyzer procedure; r = 0.996, SEy,x 0.16 mmol per L. The reference range, based on patient CSF samples, was 0.8 to 2.3 mmol per L. Elevated CSF lactate concentrations were found in patients with bacterial, but not viral, meningitis. Less marked elevations occurred with head trauma, seizures, strokes, or hemorrhage in the central nervous system. The results suggest that this method is useful in the early diagnosis of bacterial meningitis.

Clinical Laboratory Techniques↗
PubMedDate not supplied

High performance liquid chromatographic separation and fluorescence detection of polyamines in plasma and erythrocytes.

A high performance liquid chromatography has been adapted to the measurement of putrescine, spermidine and spermine in plasma and erythrocytes. Detection was by fluorimetry using o-phthalaldehyde which formed fluorophores with the polyamines. Sensitivity of the method was better than 10 pmol of each polyamine, and recovery averaged 93.9 percent. The precision of the analysis was two percent (R.S.D.). Good correlation was obtained with a reference chemical ionization gas chromatographic-mass spectrometric procedure. Reference intervals for polyamines in both plasma and erythrocytes were estimated on the basis of 25 normal volunteers.

Adult↗
PubMedDate not supplied

Evaluation of an automated radioimmunoassay for serum cortisol.

The performance characteristics are reported for a serum cortisol assay using the GAMMAFLO Automated Assay System, an automated continuous-flow system for radioimmunoassay (RIA). This automated system utilizes a combination of continuous-flow methodology and column chromatography techniques. The cortisol assay studied had a standard curve range of 10.0 to 500 microgram per L. The intra-assay and inter-assay precision were 5.1 percent and 7.2 percent (RSD), respectively, for a cortisol concentration of 160 microgram per L. The automated serum cortisol results correlated (r = 0.958 and 0.933) with two established manual radioimmunoassay procedures. No drift or carryover was detectable in 200 within-assay consecutive determinations performed at a rate of 42 determinations per hour (five hours continuous operation). The automated system studied appears to offer a viable alternative to cortisol manual RIA techniques in terms of overall precision simplicity of operation, and sample throughput.

Autoanalysis↗
PubMedDate not supplied

Long-term oral or intravenous aluminum administration in rabbits. I. Renal and hepatic changes.

Long-term aluminum (Al) administration was studied in rabbits using intravenous (I.V.) injections of aluminum maltol or oral aluminum citrate in drinking water along with calcium. In the intravenous study, renal and liver tissue Al levels increased and were associated with proximal renal tubular pathology and with hepatic periportal Al-positive multinucleated cells. After oral Al, renal Al levels were increased in the Al-hard water group, while hepatic Al levels were not significantly increased over controls. However, cirrhosis was found in five orally-loaded animals which received Al and/or low dietary calcium or soft water. Collectively, these findings suggest that renal accumulation of Al is causally related to nephrotoxicity; that the lack of renal changes after oral loading is due to low absorption from normal adult gastrointestinal tract and normal functioning of mature kidneys; and that the elevated liver Al levels, achieved after I.V. administration, are related to the presence of hepatic Al-containing giant cells.

Administration, Oral↗
PubMedDate not supplied

Lobar pilocytic astrocytomas of the cerebral hemispheres: II. Pathobiology--morphogenesis of the eosinophilic granular bodies.

This study provides new immunocytochemical observations on the so-called eosinophilic granular bodies (EGBs), seen predominantly (but not exclusively) in pilocytic astrocytomas. Using combined immunohistochemical and immunoelectron microscopic approaches on formalin-fixed, paraffin-embedded tissues, we have demonstrated that (1) EGBs exhibit pronounced reactivity with antibodies to serine protease inhibitors alpha-1-antichymotrypsin and alpha-1-antitrypsin; by immunoelectron microscopy, the reaction product is localized either in the form of diffuse floccular densities, or larger conglomerates of amorphous, globular material; (2) an antiserum to ubiquitin-protein conjugates, codistributes in the EGBs at the light microscopic level, while ultrastructurally is either localized in diffuse, finely granular deposits, and/or fragmented filamentous particles; and (3) that a monoclonal antibody to beta-amyloid precursor protein (beta-APP) stains smaller EGBs. The detection of serpin-like and beta-APP-like staining in EGBs may be a reflection of acute phase reactant activity in response to tumor-produced proteases. We postulate that EGBs contain complexes of serpins and hitherto unknown protease(s), which are in turn probably degraded via ubiquitin mediated mechanism(s). Although EGBs typify pilocytic astrocytomas, they may be exceptionally present in malignant astrocytomas, calling for cautious interpretation of their biologic as well as prognostic import.

Adolescent↗
PubMedDate not supplied

Long-term oral aluminum administration in rabbits. II. Brain and other organs.

Aluminum (Al) was given orally as a citrate salt in either hard or soft water in combination with low or normal dietary calcium intake over the duration of 12 months using 60 healthy, young adult male New Zealand white rabbits, age four to seven months, divided into six groups. Although decreased weight gain was noted, no significant histological changes were found in the central or peripheral nervous system or in multiple other organs except for liver, nor were tissue levels of Al elevated in brain or liver. However, Al in renal tissue was increased after 52 weeks of treatment in Group 1 (which received Al and a low calcium diet), in spleen in Groups 1 and 2 (on Al and a low calcium diet), and in bone in Group 1. Thus, although the mature intestine acts as a relatively impermeable barrier, some Al is, in fact, absorbed and deposited.

Aluminum↗
PubMedDate not supplied

Rapid enzymatic determination of amylase in serum and urine using a centrifugal analyzer.

A convenient, totally enzymatic procedure for amylase assay using a centrifugal analyzer is described. The reaction scheme is examined using both starch and maltotetroase as substrates. Data for the reaction kinetics, linearity and sensitivity are presented. The proposed method exhibits linear reaction kinetics between three and five minutes after the initiation of the reaction and is linear to 1200 U per liter of amylase. The determination is rapid, (five minutes analysis time), convenient, (only one reagent), and precise, (1.2% within-day C.V. and 4.6% day-to-day C.V.), at a level of 62 U per liter. The proposed method compares favorably with chromogenic procedures; (r = 0.979, n = 84).

Amylases↗
PubMedDate not supplied

Modifications to the in situ TUNEL method for detection of apoptosis in paraffin-embedded tissue sections.

The in situ detection of cells undergoing apoptosis is increasingly important in the analysis of injury and degeneration in the central nervous system. Limited information is presently available on the quantification of apoptosis in paraffin-embedded brain tissue sections, a technique which would be most useful in the evaluation of archival tissue for diagnostic and experimental purposes. In this report, optimized conditions for tissue digestion and permeabilization using Proteinase K and Triton X and a quantification method for apoptosis detection are described using brain sections from aluminum maltolate-treated aged and young rabbits as compared to untreated matched controls. This method provides optimal staining of apoptotic cells without the problem of tissue destruction, and should prove useful in evaluating the process of apoptosis in neurodegenerative disorders.

Aging↗