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Biomedical subjects

J M Herron

Publications and source records attributed to J M Herron.

At least 19 recordsLinked to original sources
PubMed2001

Aging selectively suppresses vasoactive intestinal peptide messenger RNA expression in the suprachiasmatic nucleus of the Syrian hamster.

Aging leads to many changes in the expression of circadian rhythms, including reduced amplitude, altered relationship to the environmental illumination cycle, and reduced sensitivity to phase resetting signals. Neuropeptide synthesizing neurons in the suprachiasmatic nucleus (SCN), the principal circadian pacemaker in mammals, play a role in regulating pacemaker function and in coupling the pacemaker to overt circadian rhythms. Aging may alter the activity of neuropeptide neurons in the SCN, which could be reflected in changes in mRNA expression. Therefore, this study investigated whether aging alters the level or rhythm of expression of neuropeptide mRNAs in the SCN of male Syrian hamsters, a well established model for the study of age-related changes in circadian rhythms. Three age groups of hamsters (young [3--5 months old], middle-aged [12--15 months old] and old [19--22 months old] were sacrificed at five times of day. Their brains were dissected and sections through the suprachiasmatic nucleus were prepared and used for in situ hybridization for mRNAs for vasoactive intestinal peptide (VIP), arginine vasopressin (AVP) and somatostatin (SS). Aging selectively decreased the SCN expression of VIP mRNA without affecting AVP mRNA or SS mRNA. Also, only AVP mRNA expression exhibited a robust 24-h rhythm, in contrast to previous findings in other species that VIP mRNA and SS mRNA, as well as AVP mRNA, exhibit 24-h rhythms in the SCN. The present findings suggest that age-related reductions in VIP mRNA expression may contribute to the alterations in entrainment and attenuated sensitivity to phase resetting signals that are characteristic of aging. Furthermore, the results demonstrate that neuropeptide gene expression in the SCN is differentially regulated by aging and varies among species.

Aging↗
PubMed2001

Pulmonary vascular response to normoxia and K(Ca) channel activity is developmentally regulated.

To address developmental regulation of pulmonary vascular O(2) sensing, we tested the hypotheses that 1) fetal but not adult pulmonary artery smooth muscle cells (PASMCs) can directly sense an acute increase in O(2), 2) Ca2+-sensitive K(+) (K(Ca)) channel activity decreases with maturation, and 3) PASMC K(Ca) channel expression decreases with maturation. We used fluorescence microscopy to confirm that fetal but not adult PASMCs are able to sense an acute increase in O(2) tension. Acute normoxia induced a 22 +/- 2% decrease in cytosolic Ca2+ concentration ([Ca2+](i)) in fetal PASMCs and no change in ([Ca2+](i)) in adult PASMCs (P < 0.01). The effects of K(+) channel antagonists were studied on fetal and adult PASMC ([Ca2+](i)). Iberiotoxin (10(-9) M) caused PASMC ([Ca2+](i)) to increase by 694 +/- 22% in the fetus and caused no change in adult PASMCs. K(Ca) channel expression and mRNA levels in distal pulmonary arteries from fetal and adult sheep were examined. Both K(Ca) channel protein and mRNA expression in the distal pulmonary vasculature decreased with maturation. We conclude that maturation-dependent changes in PASMC O(2) sensing render the fetal PASMCs uniquely sensitive to an acute increase in O(2) tension at a biologically critical time point.

Aging↗
PubMed2000

The pharmacokinetics, electrocardiographic effects, and tolerability of loratadine syrup in children aged 2 to 5 years.

OBJECTIVE: We assessed the pharmacokinetics and tolerability of 5 mg loratadine syrup (1 mg/mL) in children aged 2 to 5 years. METHODS: Two studies were undertaken. A single-dose, open-label bioavailability study was performed to characterize the pharmacokinetic profiles of loratadine and its metabolite desloratadine. Plasma concentrations of loratadine and desloratadine were determined at 0, 1, 2, 4, 8, 12, 24, 48, and 72 hours after a single administration of 5 mg loratadine syrup to 18 healthy children (11 male, 7 female; 12 black, 5 white, 1 other; mean age +/- SD, 3.8 +/- 1.1 years; mean weight +/- SD, 17.4 +/- 4.4 kg). In addition, a randomized, double-blind, placebo-controlled, parallel-group study was performed to assess the tolerability of 5 mg loratadine syrup after multiple doses. Loratadine (n = 60) or placebo (n = 61) was given once daily for 15 days to children with a history of allergic rhinitis or chronic idiopathic urticaria. In the loratadine group, 27 boys and 33 girls (52 white, 8 black) were enrolled, with a mean age +/- SD of 3.67 +/- 1.13 years and a mean weight +/- SD of 17.2 +/- 3.8 kg. In the placebo group, 27 boys and 34 girls (53 white, 7 black, 1 Asian) were enrolled, with a mean age +/- SD of 3.52 +/- 1.12 years and a mean weight +/- SD of 17.3 +/- 2.9 kg. Tolerability was assessed based on electrocardiographic results, occurrence of adverse events, changes in vital signs, and results of laboratory tests and physical examinations. RESULTS: The peak plasma concentrations of loratadine and desloratadine were 7.78 and 5.09 ng/mL, respectively, observed 1.17 and 2.33 hours after administration of loratadine; the areas under the plasma concentration-time curve to the last quantifiable time point for loratadine and desloratadine were 16.7 and 87.2 ng x h/mL, respectively. Single and multiple doses were well tolerated, with no adverse events occurring with greater frequency after multiple doses of loratadine than after placebo. Electrocardiographic parameters were not altered by loratadine compared with placebo. There were no clinically meaningful changes in other tolerability assessments. CONCLUSION: Loratadine was well tolerated in this small, selected group of children aged 2 to 5 years at a dose providing exposure similar to that with the adult dose (ie, 10 mg once daily).

Anti-Allergic Agents↗
PubMed2000

Effects of luminance and resolution on observer performance with chest radiographs.

PURPOSE: To examine the combined effects of image resolution and display luminance on observer performance for detection of abnormalities depicted on posteroanterior chest radiographs. MATERIALS AND METHODS: A total of 529 radiographs were displayed on a specially constructed view box at three luminance levels (770, 260, and 85 cd/m(2)) and three resolutions (100-microm, 200-microm, and 400-microm pixels). Each image was reviewed nine times by six radiologists who participated in this study. The abnormalities included nodule, pneumothorax, interstitial disease, alveolar infiltrates, and rib fracture. Negative (normal) radiographs were also included. RESULTS: Receiver operating characteristic curves indicated that the effect of image luminance was greater than that of resolution. The detection of pneumothorax, interstitial disease, and rib fracture showed statistically significant differences (P <. 05) due to luminance. The detection of pneumothorax was the only abnormality with a statistically significant difference due to resolution. There was no evidence that luminance was related to image resolution for any of the abnormalities. CONCLUSION: At a resolution of 400-microm pixels or higher across the field of view and a luminance of 260 cd/m(2) or more, primary diagnosis with posteroanterior chest radiographs is not likely to be affected by the quality of display.

Analysis of Variance↗
PubMed2000

Chronic intrauterine pulmonary hypertension decreases calcium-sensitive potassium channel mRNA expression.

Calcium-sensitive potassium (K(Ca)) channels play a critical role in mediating perinatal pulmonary vasodilation. Because infants with persistent pulmonary hypertension of the newborn (PPHN) have blunted vasodilator responses to birth-related stimuli, we hypothesized that lung K(Ca) channel gene expression is decreased in PPHN. To test this hypothesis, we measured K(Ca) channel gene expression in distal lung homogenates from both fetal lambs with severe pulmonary hypertension caused by prolonged compression of the ductus arteriosus and age-matched, sham-operated animals (controls). After at least 9 days of compression of the ductus arteriosus, fetal lambs were killed. To determine lung K(Ca) channel mRNA levels, primers were designed against the known sequence of the K(Ca) channel and used in semiquantitative RT-PCR, with lung 18S rRNA content as an internal control. Compared to that in control lambs, lung K(Ca) channel mRNA content in the PPHN group was reduced by 26 +/- 6% (P < 0.02), whereas lung voltage-gated K(+) 2.1 mRNA content was unchanged. We conclude that lung K(Ca) channel mRNA expression is decreased in an ovine model of PPHN. Decreased K(Ca) channel gene expression may contribute to the abnormal pulmonary vascular reactivity associated with PPHN.

Amino Acid Sequence↗
PubMed2000

Mometasone furoate has minimal effects on the hypothalamic-pituitary-adrenal axis when delivered at high doses.

STUDY OBJECTIVES: To investigate the potential for mometasone furoate (MF) to exert systemic effects following administration by dry powder inhaler (DPI) or metered-dose inhaler (MDI). DESIGN: Three randomized, evaluator-blind, placebo-controlled, parallel-group, 28-day studies. PATIENTS: Adults with mild-to-moderate persistent asthma. INTERVENTIONS: Study 1 (12 patients per treatment group; MF DPI at 200 microg bid, 400 microg qd, 800 microg qd, or 1,200 microg qd). Study 2 (16 patients per treatment group; MF DPI at 400 microg bid or 800 microg bid, or oral prednisone at 10 mg qd). Study 3 (16 patients per treatment group; MF MDI at 400 microg bid or 800 microg bid, or fluticasone propionate [FP] at 880 microg bid by MDI). MEASUREMENTS AND RESULTS: Study 1. Plasma concentrations were near the lower limit of quantitation (50 pg/mL) at the MF DPI 400-microg qd dosage and approximately 250 pg/mL at the 1,200-microg qd dosage. The area under the curve for serum cortisol concentrations over 24 h (AUC(24)) was essentially unaltered at all doses. Study 2. Plasma levels over days 7 to 28 were 100.3 +/- 5.9 pg/mL (mean +/- SEM) for MF DPI 400 microg bid, and 181.0 +/- 10.9 pg/mL for 800 microg bid. Although there were relatively low levels of suppression (19 to 25%) at earlier time points for MF DPI 400 microg bid, serum cortisol AUC(24) levels at day 28 were similar to placebo. MF DPI 800 microg bid and oral prednisone both decreased serum cortisol AUC(24) levels at days 7 to 28 by 28.0 +/- 8.3% and 67.2 +/- 3.6%, respectively. The response to cosyntropin was normal in 15, 14, 11, and 1 of the patients in the placebo, MF DPI 400 microg bid, MF DPI 800 microg bid, and prednisone groups, respectively. Study 3. MF MDI caused even less systemic exposure than by DPI. MF MDI 800 microg bid (24.0 +/- 3.1%) and FP (51.7 +/- 3.8%) caused a significant decrease in serum cortisol AUC(24) on days 14 to 28. MF MDI 400 microg bid was similar to placebo treatment at all time points. CONCLUSIONS: The MF 800-microg bid dosage (1,600 microg/d), which is twice the highest projected clinical dosage, represents the lower limit for consistently detectable systemic effects of MF.

Administration, Inhalation↗
PubMed1998

A systemic bioactivity comparison of double-strength and regular-strength beclomethasone dipropionate MDI formulations.

BACKGROUND: The efficacy and safety of regular-strength beclomethasone dipropionate MDI prescribed within its recommended dosing range of 2 to 5 puffs three to four times daily has been well established in more than 25 years of worldwide use. A more concentrated formulation delivering 84 microg per puff was developed to provide for a more convenient twice-daily dosing regimen. OBJECTIVE: This randomized, single-blinded, positive and placebo-controlled, parallel-group, multiple-dose bioactivity study was conducted to assess the potential of a new beclomethasone dipropionate 84 microg double-strength metered-dose inhaler (Vanceril 84 microg Double Strength Inhalation Aerosol/Key) to cause hypothalamic-pituitary-adrenocortical axis suppression. METHODS: Beclomethasone dipropionate double-strength 84 microg was compared with beclomethasone dipropionate regular-strength 42 microg, orally administered prednisone, and placebo inhaler after 36 consecutive days of administration in adults with moderate asthma. Beclomethasone dipropionate double-strength was administered as 5 puffs BID and beclomethasone dipropionate regular-strength was administered as 10 puffs BID for the same total daily dose of 840 microg of beclomethasone dipropionate. Oral prednisone was administered by mouth at 10 mg once a day. The potential for hypothalamic-pituitary-adrenocortical axis suppression was evaluated by an adrenocorticotropic hormone (ACTH) stimulation test using cosyntropin 250 microg in 500 mL normal saline infused over six hours on the 36th day of treatment. Sixty-four patients completed this study. RESULTS: No clinically significant post-study findings were observed from physical examination, electrocardiogram, or clinical laboratory evaluation for any treatment group. No serious or unexpected adverse events were reported. On the 36th day of treatment, there was a significant (P < .01) difference in the plasma cortisol concentration response to cosyntropin stimulation between the prednisone and placebo treatment groups at the sixth hour of infusion. There was no significant difference in the plasma cortisol concentration response to cosyntropin stimulation between the beclomethasone dipropionate double-strength and beclomethasone dipropionate regular-strength treatment groups and the placebo group. In addition, comparison of the response between the beclomethasone dipropionate double-strength and beclomethasone dipropionate regular-strength groups showed no significant difference. CONCLUSION: Beclomethasone dipropionate, administered either via a double-strength (84 microg/puff) or regular-strength (42 microg/puff) inhaler dosed at 840 microg/day showed no evidence of hypothalamic-pituitary-adrenocortical axis suppression in adults with moderate asthma.

Administration, Inhalation↗
PubMed1997

Proteinase-free myeloperoxidase increases airway epithelial permeability in a whole trachea model.

In cystic fibrosis the bronchiectatic conducting airways have large numbers of neutrophils in their walls and in their luminal contents. The neutrophil's primary granule enzyme activities of elastase and peroxidase are increased in the sputum of these patients. It has been postulated that these enzymes--together or individually--act to damage the airway epithelium. However, only peroxidase activity has consistently correlated with the degree of structural and functional airway disease in these patients with leakage of plasma protein into the airway lumen (Regelmann et al., Pediatr Pulmonol, 1995; 19:1-9). The present study was designed to test whether human neutrophil-derived myeloperoxidase can independently produce bronchial epithelial damage without the presence of proteases, as measured by increased permeability of the airway epithelium. Human peripheral blood neutrophils were purified, their primary granules isolated, and their peroxidase purified using affinity and ion exchange column chromatography. Activity of the proteinase-free peroxidase was measured using a chromogenic substrate. The effect of this peroxidase on the permeability of excised rat tracheas was measured using radioactive and fluorescent-labeled non-ionic molecules of varying molecular weight. Rat tracheas exposed to 15 minute treatments with either 130 U of peroxidase or hydrogen peroxide (10(-5) M) did not show a significant increase in the permeability of the epithelium to [3H]inulin, [14C]sucrose, and fluorescein isothiocyanate dextran 20 compared with control tracheas. However, those tracheas exposed to 130 U peroxidase followed by 10(-5) M hydrogen peroxide showed an increased permeability to each of the three test solutes. We conclude that proteinase-free myeloperoxidase, in the presence of non-toxic concentrations of its substrates, hydrogen peroxide and halide, produced increases in permeability to non-ionic molecules in the rat trachea within 15 minutes.

Animals↗
PubMed1997

Preliminary clinical evaluation of a high-resolution telemammography system.

RATIONALE AND OBJECTIVES: The authors designed, assembled, tested, and clinically evaluated a high-quality, fast, and relatively inexpensive telemammography system. METHODS: The authors designed a telemammography system that uses a high-resolution film digitizer and high data compression (> or = 40:1) to send images over regular telephone lines to a high-resolution laser printer that produces images with the look and feel of the original image and can operate in a hub and spokes mode. The authors then evaluated the system's performance. In a preliminary clinical study, interpretations of the laser-printed system's output of 119 cases were compared with the original interpretations, followed by a review of any clinically significant differences. RESULTS: With the exception of the laser printer, which is a modified off-the-shelf product, all hardware components of the system are commercially available products. The system digitizes (50 microns pixel size), compresses, transmits, receives, decompresses, and prints a 30 MB mammography file in less than 4 minutes. In the clinical study, there were 13 differences (in 13 cases) in the level of concern or recommendations. Seven were found to be clinically insignificant by a third-party review. The remaining six were reviewed by the original interpreter, and three were determined to be significant enough for further action. All were found to result from intra-reader variability rather than differences in visualization of possible abnormalities. CONCLUSIONS: Almost real-time, high-quality telemammography without geographic boundaries is possible with the use of high-level data compression. Telemammography with laser-printed film as the display may make it possible to offer mammographic services in remote locations while using commercially available technology.

Evaluation Studies as Topic↗
PubMed1995

Sputum peroxidase activity correlates with the severity of lung disease in cystic fibrosis.

Patients with cystic fibrosis (CF) of the same age differ significantly in their degree of pulmonary disease. Based on preliminary observations, we postulated that the activity of myeloperoxidase would be significantly increased in patients with greater structural lung damage than in those with less lung damage. Acid extracts of weighed sputum samples were assayed for lactoferrin concentrations by ELISA. Activities of peroxidase, cathespsin G, and elastase (with and without proteinase 3) were determined by kinetic analysis using chromogenic substrates. The patients were divided into quartiles based on their Brasfield chest-radiograph score. Patients in the first quartile (least amount of structural lung abnormality) were compared to those in the fourth quartile. The concentration of lactoferrin, a specific (secondary) granule protein of neutrophils, did not differ between the two patient groups. However, the activities of the neutrophil primary granule proteins, peroxidase, elastase, and elastase plus proteinase 3, were significantly elevated in the group with the most structural lung abnormality. Sputum albumin concentration was used to estimate leakages of plasma proteins into the airways. Peroxidase activity, but not the activity of cathepsin G, of elastase, or of elastase plus proteinase 3, correlated significantly with albumin/g sputum in both quartile groups. To confirm the association of sputum peroxidase activity with differences in lung structure and to test its correlation with lung function, spirometry was performed in a second group of patients during the week prior to the time of sputum sampling. In this second group, increased sputum peroxidase activity was associated with worse Brasfield scores and with decreased percent-predicted forced expiratory volume in 1 sec.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Fosinopril monotherapy: relationship between blood pressure reduction and time of administration.

The time to peak antihypertensive effect and the trough-to-peak ratio were determined in 64 Caucasian patients (19 men, 45 women) with mild to moderate hypertension [supine diastolic blood pressure (DBP) 95 to 115 mmHg]. They received placebo or fosinopril 10, 20, or 40 mg once daily for 4 weeks. The study consisted of a 4-week placebo lead-in, 4 weeks' double-blind treatment, and a 1-week placebo washout period. Vital signs were determined biweekly before dosing, and blood pressures were measured every 1 to 2 h during two 27-h periods at the beginning and end of treatment. After the first and last doses of all three regimens, the peak effect on blood pressure occurred 5 to 7 h after all three dosages. Neither peak nor trough blood pressure changes showed a clear dose-response relationship. Trough to peak ratios for the first dose, corrected for placebo effects, were 79% for fosinopril 10 mg, 48% for fosinopril 20 mg, and 74% for fosinopril 40 mg, and the trough-to-peak ratios for the last dose were 41% for fosinopril 10 mg, 32% for fosinopril 20 mg, and 44% for fosinopril 40 mg. In the 38 responders among the 48 patients receiving fosinopril (supine DBP decrease of at least 5 mmHg at 24 h postdose), trough-to-peak ratios ranged from 50 to 81%, and the range indicates that fosinopril is efficacious when administered once daily. Adverse effects were mild to moderate, and no patient discontinued treatment. Changes in the laboratory test results, electrocardiograms, or the results of physical examinations were unremarkable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Increased monocyte oxidase activity in cystic fibrosis heterozygotes and homozygotes.

Freshly isolated monocytes from cystic fibrosis (CF) heterozygotes and homozygotes had significantly increased oxygen uptake and superoxide formation after surface glycoprotein stimulation than did monocytes from age- and sex-matched controls. Lack of differences among the genotypes in inhibition by simple sugars of the concanavalin A-stimulated superoxide production and lack of differences in concanavalin A-binding surface proteins suggested that different regulation of the oxidase pathway produced the increased oxygen uptake and superoxide formation in CF patients and carriers. This regulatory role is consistent with the predicted structure of the CF gene product. The results support the hypothesis that the mononuclear phagocytes of CF heterozygotes have a significantly increased ability to kill intracellular microbes and may confer a selective advantage to the host.

Adolescent↗
PubMed1989

Sustained-release diltiazem: duration of antihypertensive effect.

The antihypertensive activity of a sustained-release preparation of diltiazem (given each 12 hours) was assessed in 96 patients with supine diastolic blood pressure (BP) between 95 and 110 mm Hg in a multicenter, randomized, double-blind, placebo run-in, parallel-group trial comparing optimally titrated doses of diltiazem and placebo. The aim was to assess the onset of action as well as the extent and variability of BP control of this formulation during the 12-hour interval. Diltiazem was titrated from 120 mg bid to 180 mg bid as necessary to lower BP. At baseline, on the first day of titration, and at the end of 8 weeks, BP was evaluated at 0, 1, 2, 3, 4, 5, 6, 8, 10, and 12 hours after dosing. The onset of action was within 2 hours, and the effect was maintained throughout the 12-hour period. Mean BP for the diltiazem group at baseline was 154/101 mm Hg. At week 8, BP was 148/93 mm Hg at hour "0" (P less than .02 and P = .0001 for systolic and diastolic BP vs. placebo), 139/84 mm Hg at the nadir at hour 5 (P = .0001), and 149/91 mm Hg at the end of the 12-hour period (P less than .02 and P = .0001 for systolic and diastolic BP). Diltiazem was significantly more effective than placebo (P = .0001) with 50% of patients controlled to a diastolic pressure of less than 90 mm Hg at 7 of the 10 evaluation points, including the evaluation point of 12 hours post-dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Metabolic effects of antihypertensive therapy with a calcium antagonist.

The effect of diuretics to increase serum glucose, low-density lipoprotein cholesterol and triglycerides, as well as the adverse changes in triglycerides and high-density lipoprotein cholesterol produced by nonselective beta blockers, have been largely ignored in the treatment of hypertension. However, a number of trials have shown that reductions in serum lipids can alter cardiovascular mortality. Calcium antagonists have become major drugs in the treatment of hypertension, and some data suggest that calcium antagonists may increase serum glucose levels. Significantly less data on lipid effects have been published. Lipid and glucose effects were examined in an 8-week antihypertensive study using a sustained-release preparation of diltiazem titrated from 240 to 360 mg/day in a twice-daily regimen in a randomized, double-blind, placebo-controlled parallel trial in 96 patients. Average supine blood pressure at week 8 was 156/98 mm Hg, standing blood pressure with placebo 152/100 mm Hg, and with diltiazem 147/91 and 144/93 mm Hg. There were no statistically significant changes in serum lipids or glucose in the diltiazem or placebo group or between the groups. Mean values (mg/dl) at baseline and week 8 in the diltiazem group were, respectively, for cholesterol 215 and 218, high-density lipoprotein cholesterol 50 and 51, low-density lipoprotein cholesterol 128 and 133, triglycerides 169 and 175, and glucose 113 and 110. Thus, this large and placebo-controlled study shows that diltiazem is among the antihypertensives with no adverse long-term lipid or glucose effects.

Blood Glucose↗
PubMed1987

Roxithromycin in the therapy of Streptococcus pyogenes throat infections.

Roxithromycin in two dosage regimens was compared with erythromycin in the therapy of 227 patients with throat infectious due to Streptococcus pyogenes. All three groups had the same clinical efficacy but roxithromycin 300 mg daily was less effective than erythromycin 500 mg qds in eradicating S. pyogenes while there were less antibiotic-related side effects with roxithromycin 150 mg bd than with erythromycin.

Adolescent↗
PubMed1983

Nonsurgical management of extradural hematomas in children.

With the advent of computerized tomography (CT), an increasing number of patients with only minimal neurological symptoms and no signs of brain herniation are found to harbor subacute or chronic extradural hematomas (EH's). The authors present the cases of 11 symptomatic but neurologically normal children with medium to large EH's managed by close observation. These EH's were discovered 4 hours to 6 days after injury; three were in the posterior fossa, seven over the frontoparietal convexity, and one in the temporal fossa. These clots were followed by serial CT scans. Nine children recovered without surgery from 4 to 18 days after injury, and all had evidence on CT of spontaneous clot resorption. Of these nine EH's, five clots displayed volume expansion from 5 to 16 days after injury before final resorption occurred. Expansion correlated with persistence or increase in symptoms, whereas resorption correlated with improvement. Two patients showed gradual uncal herniation on Days 6 and 8, respectively, presumably during the "expansile phase" of their clots. Both had emergency craniotomy and recovered without morbidity. It is hypothesized that the resorption dynamics of the subacute or chronic EH are similar to that of the chronic subdural hematoma, with predictable volume changes, and the outcome of each lesion depends on the interplay between the patient's intracranial pressure buffering capacity and the rate of volume change. If subtle signs of brain dysfunction are adopted to signal the failure of conservative treatment and the need for craniotomy, these patients may be safely, and many successfully, managed without surgery. Factors that influence outcome of medical treatment include the size, location, configuration, and the rapidity of accumulation of the clot, the presence of associated intradural lesions, the extracranial decompression of blood through skull diastases, and the age of the patient. These factors, the criteria for patient selection, and the indications for immediate operative intervention are discussed.

Adolescent↗
PubMed1982

Diode array digital radiography: initial clinical experience.

Initial clinical results are described for a new method of digital radiography based on high-detail self-scanning linear diode arrays which overcome many of the limitations of present film or other digital methods. The technique uses a fan-shaped x-ray beam to produce a nearly scatter-free image on a phosphor strip that is fiber-optically coupled to six self-scanning arrays of light-sensitive diodes spaced 0.025 mm, thus providing 6,144 discrete sensors across the field of view. Because these diodes have a greatly expanded dynamic range and operate at very low noise, it becomes possible to visualize small density differences or contrast below 1% both in the light and dark areas of the image. Because of the efficiency of detection and display, radiation doses can be reduced for a given information content. Our preliminary clinical studies have shown to broad application of our method in examining the chest and abdomen and in performing intravenous digital arteriography.

Angiography↗