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Biomedical subjects

C Metz

Publications and source records attributed to C Metz.

At least 91 records · Page 5Linked to original sources
PubMed1992

Platelet imipramine binding in depressed children and adolescents.

Kinetic constants of platelet imipramine binding were determined in youths with major depression, and a contrast group. Subjects actively depressed (N = 10) had significantly fewer imipramine binding sites (Bmax) (877 +/- 148 fmol/mg protein) than recovering depressives (N = 12) (1220 +/- 428 fmol/mg protein) and contrasts (N = 10) (1270 +/- 230 fmol/mg protein). Affinity constants (Kd) (1.14 +/- 0.36 nM, 0.97 +/- 0.31 nM, and 1.17 +/- 0.39 nM, respectively) were similar among the groups. Actively depressed males but not females had fewer imipramine binding sites than both their sex-matched comparison groups. Although actively depressed females' Bmax was significantly lower than recovering depressed and nondepressed males, neither age, Tannner stage, nor circannual rhythms influenced Bmax, but suicidality may be associated with low Bmax. A decrease in Bmax may be a state-specific marker of major depression in boys or associated with a depressive disorder with a suicidal history.

Adolescent↗
PubMed1991

Concurrent validity and psychometric properties of the Beck Depression Inventory in outpatient adolescents.

The concurrent validity of the Beck Depression Inventory (BDI) was evaluated in 122 outpatient adolescents referred to a clinic for depression. Criterion validators were Kiddie-Schedule for Affective Disorders and Schizophrenia (K-SADS) generated diagnoses and a 17-item clinician-rated depression scale extracted from the K-SADS. Initial BDI scores of greater than 13 yielded sensitivity, specificity, and positive predictive powers of 86%, 82%, and 83%, respectively, in differentiating syndromal major depressive disorder (MDD) from nonaffective disordered patients. In repeated interviews in 2 weeks with a BDI score of greater than 13, these parameters were 89%, 88%, and 93%, respectively, in those meeting MDD criteria. The BDI correlated significantly with the 17-item depression score in depressed females but not depressed males because BDI scores were more than 30% higher in females. BDI internal consistency among all cases was 0.91 and was higher in depressed than nondepressed patients.

Adolescent↗
PubMed1991

Anti-inflammatory therapy for acute lung injury. A review of animal and clinical studies.

The adult respiratory distress syndrome (ARDS) continues to demonstrate high mortality. This syndrome is frequently observed as a remote complication of another disease process and is characterized by a significant inflammatory component. The purpose of this review is to compare and contrast published research on the use of anti-inflammatory agents, steroidal and nonsteroidal, in animal models of acute lung injury. Emphasis is given to the nature of the experimental pulmonary injury, infusion (ie, oleic acid and zymosan-activated plasma) or bacteriologically (ie, endotoxin and live bacteria) induced and the timing of drug administration relative to induction of the insult. The clinical data available on the use of these drugs in ARDS are discussed, and a rationale is presented for future clinical trials in these patients.

Animals↗
PubMed1990

Autoregulation of the glomerular filtration rate and the single-nephron glomerular filtration rate despite inhibition of tubuloglomerular feedback in rats chronically volume-expanded by deoxycorticosterone acetate.

Tubuloglomerular feedback (TGF) function and autoregulation (renal blood flow RBF; glomerular filtration rate, GFR; single-nephron glomerular filtration rate, SNGFR) were examined in rats chronically treated with deoxycorticosterone acetate (DOCA) and given isotonic saline to drink. DOCA treatment depressed arterial plasma renin activity, expanded plasma volume by 25% and increased arterial blood pressure. Autoregulation of RBF and GFR was maintained in the DOCA animals above 90 mm Hg and 110 mm Hg respectively, whereby both GFR and RBF were lower than in controls. Micropuncture experiments demonstrated the absence of TGF in the DOCA animals. There was no difference between SNGFR values measured in the distal and proximal tubules, nor was there a significant response of SNGFR when loops of Henle were perfused with Ringer's solution at 20 nl/min. Loop perfusion in control rats with tubular fluid collected in DOCA rats elicited a normal TGF response, showing that TGF inhibition in the DOCA animals is due to changes in the function of the juxtaglomerular apparatus. In contrast to control rats, proximal SNGFR was perfectly autoregulated. These results suggest that TGF is not primarily responsible for autoregulation and that the vasodilatation normally resulting from acute TGF interruption is therefore compensated by some other mechanism such that RBF and GFR are lower than in controls.

Animals↗
PubMed1990

[Isolation of transcription promoters from Thiobacillus ferrooxidans and T. acidophilus and its introduction by conjugation to T. intermedius].

The chemolithotrophic acidophilic bacteria, Thiobacillus ferrooxidans is considered as the most important microorganism in relation to copper and uranium bioleaching ability. Since T. ferrooxidans is a strict chemolithotrophic microorganism, its genetic manipulation is a very hard task. Until now, all efforts have been unsuccessful. Therefore, we decided to approach the problem in steps, trying initially to manipulate some T. ferrooxidans related strains. We chose Thiobacillus acidophilus that shares its habitat with T. ferrooxidans and Thiobacillus intermedius, for its heterotrophic nature that makes them easier to grow and suitable for heterologous conjugation. The main objective of this work was directed towards the isolation and characterization of transcription promoters from T. acidophilus and T. ferrooxidans genomic DNA. Four different promoters from T. acidophilus and four from T. ferrooxidans were isolated and sequenced. In order to test their functional capacity in bacterial systems different from E. coli, they were subcloned and transferred to other bacteria. One of these recombinant plasmids was successfully transferred to T. intermedius and from it to Ps. putida. The subcloned promoter was able to confer streptomycin resistance to Ps. putida.

Base Sequence↗
PubMed1989

Videotape reliability of the third revised edition of the K-SADS.

Videotaped interrater reliability was assessed with the K-SADS-III-R on 25 children with a mean age of 10:9. Kappa statistics were computed in syndromes with a frequency rate of at least 20%. The following mean kappas were obtained: major depression = 0.83; overanxious disorder = 0.85; separation anxiety = 0.85; simple phobic disorder = 0.64; oppositional disorder = 0.89; attention deficit disorder = 0.88. The mean kappa for mother derived diagnoses was 0.86; for child derived diagnoses 0.79; and, for all diagnoses combined 0.84. These reliability findings are comparable to reports with similar methodology in the child literature. The improved kappas for the anxiety disorders achieved a primary goal for this revision of the K-SADS. This study has shown that the K-SADS-III-R has sufficient reliability for research purposes.

Anxiety Disorders↗
PubMed1988

Dawn phenomenon in type 1 (insulin-dependent) diabetic adolescents: influence of nocturnal growth hormone secretion.

In order to reassess the role of growth hormone in the dawn phenomenon, we studied eight C-peptide negative diabetic adolescents, who are likely to exhibit important nocturnal growth hormone surges. The insulin infusion rate necessary to maintain euglycaemia was predetermined in each patient from 22.00 hours to 01.00 hours, and then kept constant until 08.00 hours resulting in stable free insulin levels. Blood glucose rose from 4.3 +/- 0.7 mmol/l at 01.00 hours to 7.1 +/- 1.1 mmol/l at 08.00 hours (p less than 0.01) secondary to an increased hepatic glucose production. All the subjects presented an important growth hormone secretion, ranging from 20 to 66 ng/ml (peak values) and from 3619 to 8621 ng.min.ml-1 (areas under the curve). The insulin infusion rate selected for each patient was positively correlated with the nocturnal growth hormone secretion (area under the curve) (r = 0.87, p less than 0.01). On the other hand, there was no relationship between the nocturnal growth hormone secretion and the magnitude of the early morning blood glucose rise (r = -0.48, p greater than 0.2). We conclude that, in Type 1 (insulin-dependent) diabetic adolescents, the dawn phenomenon exists but is moderate despite important growth hormone surges; the nocturnal growth hormone secretion influences the nocturnal insulin requirements but not the dawn phenomenon itself, if insulinisation is adequate.

Adolescent↗
PubMed1987

Bactericidal activity of ofloxacin versus roxithromycin in the treatment of Streptococcus pneumoniae.

Ofloxacin is highly active against Gram-negative aerobic bacilli, but moderately active against Gram-positive cocci. The minimal inhibitory concentrations (MICs) against Streptococcus pneumoniae range between 1 and 2 mg/L. MICs of roxithromycin (RU 28965) against S. pneumoniae range between 0.004 and 0.03 mg/L, but Gram-negative bacilli are resistant. The bactericidal activities of ofloxacin and roxithromycin were evaluated against 15 strains of S. pneumoniae, which were isolated recently from clinical specimens. Killing activity was evaluated under conditions simulating serum pharmacokinetic parameters. Initial concentrations were 10 mg/L for roxithromycin and 2 mg/L for ofloxacin, and the half-life was 6 hours for both compounds. Under these conditions, roxithromycin was rapidly bactericidal. The speed at which pneumococci were killed was faster with roxithromycin than with ofloxacin. No regrowth was seen with roxithromycin, but regrowth occurred in 8 of 15 strains with ofloxacin.

Anti-Bacterial Agents↗
PubMed1984

Factor analysis as a tool in community diagnosis.

For the family physician, community diagnosis can be likened to individual diagnosis by the application of methods of information acquisition and analysis. This paper describes the technique of factor analysis, applied to data from an urban inner-city area, for reducing a multitude of factors to a manageable number without an appreciable loss of information. The variables were selected from four broad categories which have been shown to influence both health states and health care needs: demography, socioeconomics, social disorganization and morbidity/mortality. A correlation matrix based on 40 of the most accessible indices served as input for a principal axes factor analysis. Six factors accounted for 74% of the total variance and were interpreted as: 'Poverty and social disorganization', 'Distribution and problems of the elderly', 'Ethnic composition', 'Fertility', 'Infant mortality' and 'Foetal mortality'. Representative indices from each factor were then mapped to identify and display census tract differences. Finally, the application of the factors to a specific community illustrated important differences within the community and identified areas of high risk and need.

Factor Analysis, Statistical↗
PubMed1981

A cost-effectiveness analysis of screening for hepatitis B surface antigen in India.

We have developed a quantitative model to study the impact of screening for the hepatitis B surface antigen using either second-generation (counterimmunoelectrophoresis) or third-generation (radioimmunoassay) tests. This model was fashioned for general use but was applied to data on hepatitis for India, in an attempt to determine what factors would most influence the decision to institute a screening program for the surface antigen in that country. Screening for the surface antigen should reduce post-transfusion hepatitis B significantly--second-generation testing by 81% and third-generation testing by 99.4%. The marginal cost of substituting counter-immunoelectrophoresis testing for no testing is 557 rupees per case averted, and that of substituting radioimmunoassay for counterimmunoelectrophoresis testing is 1,120 rupees per case averted. Sensitivity analyses suggest that the major impact on costs will result not from changes in the sensitivity or specificity of new screening tests, but rather in their costs.

Cost-Benefit Analysis↗
PubMed1977

Comparison of Ga-67 citrate images obtained with rectilinear scanner and large-field Anger camera.

Two methods for Ga-67 citrate imaging were compared on 20 patients. Scans were performed using approximately equal procedure time with two instruments: (A) a dual 5-in. rectilinear scanner with medium-energy collimator, with a single window spanning both the 93-keV and the 185-keV spectral peaks; and (B) a large-field (15-in. diam) Anger camera equipped with moving table, medium-energy collimator, and three windows covering the 93-keV, 185-keV, and 300-keV peaks separately. Sixteen abnormal sites and 24 normal sites were selected for comparison. Each site was evaluated by four physicians experienced in interpreting Ga-67 citrate images. The observers performed significantly better using the images obtained with the large-field camera (three windows) than with the dual 5-in. scanner (single window).

Citrates↗
PubMedDate not supplied

Effects of spinal dorsal column transection on the response of monkey anterior parietal cortex to repetitive skin stimulation.

The pattern of 14C-2-deoxyglucose (2DG) labeling in anterior parietal cortex was evaluated in three groups of experimental subjects: (1) subjects in which all spinal pathways projecting at short latency to the contralateral hemisphere were intact, (2) subjects with either unilateral or bilateral transection of the dorsal column pathway, and (3) subjects in whom a two-stage tractotomy (dorsal column isolation) restricted short-latency mechanoreceptor drive to that conveyed via the dorsal column pathway. Macaca fascicularis and Macaca arctoides monkeys were studied. When the spinal cord pathways projecting at short latency to contralateral anterior parietal cortex were intact, controlled vibrotactile or skin brushing stimuli evoked one or, more rarely, several loci of maximal 2DG uptake (typically 1.5-2.5 mm in diameter) in the topographically appropriate location(s) within area 3b and/or area 1. The labeling at each locus of maximal 2DG uptake extended continuously across layers II-VI. Each locus of maximal 2DG uptake was bordered on one or more sides by irregularly shaped zones of below-background 2DG uptake that could extend without interruption from area 3b into area 3a, and/or from area 1 into area 2. In the absence of skin stimulation, little or no above-background 2DG uptake occurred at any locus within areas 3b and 1 of subjects in which the dorsal column pathway on the opposite side of the spinal cord was intact. In subjects with a complete transection of the spinal dorsal column the global 2DG pattern evoked by a repetitive skin stimulus in contralateral anterior parietal cortex was a near mirror image of the pattern evoked by the same stimulus in intact subjects. In the absence of the dorsal column path, neither 10-25 Hz vibrotactile nor brushing stimulation evoked above-background uptake at the topographically appropriate location(s) within contralateral area 3b and/or area 1. Instead, a prominent region of below-background 2DG uptake occupied the topographically appropriate location in area 3b and/or area 1, and the region of suppressed 2DG uptake was bounded by one or more regions of above-background 2DG uptake that extended from areas 3b or 1 into area 3a and/or into area 2. When a two-stage spinal tractotomy prevented stimulus-evoked short-latency input from reaching contralateral anterior parietal cortex via pathways other than the dorsal column, the 2DG activity patterns evoked in contralateral cortex by either brushing or vibrotactile stimuli were similar to the patterns obtained when the somatosensory pathways on the opposite side of the spinal cord were intact. A neural network model was developed to evaluate the hypothesis that the observed cortical effects of dorsal column transection might be attributable, at least in part, to inhibitory interactions among anterior parietal cortical regions that receive their principal input from different spinal cord pathways. The model incorporated known features of (1) the cortical projection of spinal somatosensory pathways, (2) anterior parietal intrinsic and long-distance horizontal connectivity, and (3) certain neurotransmitter/receptor systems characteristic of sensory neocortex. Simulations of the model network provided results consistent with the idea that repetitive skin stimuli evoke maladaptive, time-dependent corticocortical interactions within anterior parietal cortex contralateral to a dorsal column lesion. The observations indicate that corticocortical interactions account for the (1) near mirror-image pattern (relative to the normal Mexican hat-like pattern) of anterior parietal stimulus-evoked 2DG uptake observed in subjects with a dorsal column lesion, (2) unusual time-dependent response properties of individual area 3b and 1 neurons or neuron populations deprived of dorsal column input (Dreyer et al., 1974; Vierck et al., 1990a; Makous and Vierck, 1994), and (3) abnormal time-dependent characteristics of tactile perception in monkeys with dorsal colum

Acoustic Stimulation↗
PubMedDate not supplied

[Intraventricular hemorrhage in utero].

A case of fetal intraventricular hemorrhage related to subependymal hemorrhage diagnosed by ultrasound scanning at 27 weeks of PMA is reported. No etiology was found. The outcome was favorable. This case suggests that some cases of neonatal idiopathic hydrocephalus may be explained by fetal subependymal/intraventricular hemorrhage.

Blood Coagulation Disorders↗