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Biomedical subjects

E J McDonald

Publications and source records attributed to E J McDonald.

16 recordsLinked to original sources
PubMed2000

Effects of environmental noise on computer-derived voice estimates from female speakers.

The purpose of this study was to examine the influence of noise on voice profile statistics from female samples. Six young adult females served as subjects. Five had normal voices; one had a pathological voice with accompanying bilateral vocal nodules. Each female subject was required to match a generated 235 Hz tone (+/- 2 Hz) while maintaining a constant output level of 70 dB SPL (+/- 5 dB). Data collected from a previous study involving a normal male subject were included for comparative purposes. Noise was generated from a personal computer fan which had a strong center frequency component at 235 Hz. Six different A-weighted signal-to-noise [S/N(A)] conditions were created, ranging in 5 dB increments from 25 to 0 dB. Results revealed that fundamental frequency was reasonably resistant to the effects of noise and to the effects of the noisy (pathological) voice signal. Jitter and shimmer estimates generally increased as noise floors elevated. The greatest amount of measurement error was found for the pathological female voice when captured in the presence of environmental noise. Findings are discussed relative to clinical issues surrounding measurement error.

Adult↗
PubMed1991

Synthesis and antitumor activity of structural analogues of the epipodophyllotoxins.

Several ring-contracted analogues of the antitumor agent etoposide have been prepared. The synthesis of the simple indanyl system 3 is described along with two bicyclic systems of general structure 4 prepared through a stereoselective allylation of the keto-ester 6. A cis-fused lactone analogue 5, which is isomeric with the etoposide aglycone, has been synthesized via a dialkylation of the indene-2-carboxylate anion. Regiochemical and stereochemical results of these alkylations are described. The cytotoxicity of these derivatives toward several tumor cell lines is described and generally follows the structure-activity relationships known for the agent podophyllotoxin (2).

Adenocarcinoma↗
PubMed1989

New macrolides active against Streptococcus pyogenes with inducible or constitutive type of macrolide-lincosamide-streptogramin B resistance.

Macrolide-resistant bacteria can be classified as inducibly resistant or constitutively resistant. Inducibly resistant bacteria are resistant to 14-membered macrolides, such as erythromycin and clarithromycin (A-56268), but are susceptible to the 16-membered macrolides, such as tylosin and spiramycin, as well as to clindamycin. Constitutively resistant bacteria are resistant to macrolide-lincosamide-streptogramin B antibiotics. In this study, the MICs of several erythromycin and clarithromycin analogs against macrolide-susceptible and macrolide-resistant Streptococcus pyogenes strains were determined. Four 11,12-carbamate analogs of clarithromycin had lower MICs than erythromycin did against S. pyogenes with the inducible or constitutive type of macrolide-lincosamide-streptogramin B resistance. Five 11,12-carbonate analogs of erythromycin with modifications at the 4" position of cladinose had lower MICs than did erythromycin against S. pyogenes with the constitutive type of resistance, and one of these compounds, which had a naphthyl-glycyl substitution at the 4" position, had a lower MIC than erythromycin against both the inducibly resistant and constitutively resistant strains. Two analogs of erythromycin with a modification on the 4" position of cladinose had lower MICs than erythromycin did against the constitutively resistant organisms but not against the inducibly resistant organisms. Thus, 14-membered macrolides can be modified so as to confer a low MIC when tested in vitro.

Aminoglycosides↗
PubMed1988

Comparative in vitro activities of new 14-, 15-, and 16-membered macrolides.

The in vitro activities of several 14-, 15- and 16-membered macrolides were compared with that of erythromycin. In general, 14-membered macrolides such as erythromycin, clarithromycin, and flurithromycin were more active against streptococci and Bordetella pertussis than was the 15-membered macrolide azithromycin, which was more active than 16-membered macrolides such as miocamycin and rokitamycin. Clarithromycin was the most active compound against Streptococcus pyogenes, pneumococci, Listeria monocytogenes, and Corynebacterium species. Legionella pneumophila was most susceptible to miocamycin, clarithromycin, and rokitamycin. Branhamella catarrhalis, Neisseria gonorrhoeae, and Haemophilus influenzae were most susceptible to azithromycin. Azithromycin and dirithromycin were the most active compounds against Campylobacter jejuni. MICs of 16-membered macrolides for strains expressing inducible-type resistance to erythromycin were less than or equal to 1 microgram/ml, whereas none of the compounds had activity against strains expressing constitutive-type resistance. The MICs of roxithromycin, miocamycin, rokitamycin, and josamycin increased in the presence of human serum, whereas MICs of the other compounds either were unchanged or decreased.

Aminoglycosides↗
PubMed1988

Effect of dosing intervals on efficacy of clarithromycin and erythromycin in mouse infection models.

Clarithromycin is a new macrolide with a serum half-life which is at least twice that of erythromycin. In order to select the appropriate dosing intervals, the in vitro post-antibiotic effect (PAE) of clarithromycin and erythromycin were compared and the efficacies of clarithromycin and erythromycin when administered once (q.d.), twice (b.i.d.) and three (t.i.d.) times a day in mouse protection tests were measured. The doses were selected from achievable peak serum concentrations in man and were 18 mg/kg for clarithromycin which gave a peak blood level of 2.0 micrograms/ml and a serum half-life of 0.82 h, and 10 mg/kg for erythromycin which gave a peak blood level of 0.9 microgram/ml and a serum half-life of 0.46 h. The PAE of clarithromycin for Staph. aureus is 6.25 h compared to 2.35 h for erythromycin. Clarithromycin was effective against Staph. aureus, Strep. pyogenes and Strep. pneumoniae when administered q.d., b.i.d. and t.i.d. and there was no difference in the cumulative mortalities in the three treatment groups. For erythromycin, there was also no difference in the survival of Strep. pyogenes and Strep. pneumoniae-infected mice, but when tested against Staph. aureus it was more effective when administered t.i.d. than b.i.d., and b.i.d. was more effective than q.d. Clarithromycin administered q.d. was more effective than erythromycin administered t.i.d. against Staph. aureus.

Animals↗
PubMed1978

Complications of catheter cerebral arteriography: analysis of 5,000 procedures. I. Criteria and incidence.

Computer analysis of complications of 5,000 catheter cerebral arteriograms performed at four hospitals (two training and two nontraining) revealed a total of 68 complications (1.4%). Eight (0.16%) of these complications were major: five patients required thrombectomy or embolectomy, two had permanent neurologic deficits, and one patient died. The complication rate for the training hospitals (3.9%) was significantly higher than that for the nontraining hospitals (0.9%), but the rates of permanent complications were identical in both groups (0.1%). Reporting criteria and complication types are described.

Adult↗
PubMed1977

Ultrasonographic assessment of neck masses.

Fourteen patients are presented to illustrate the usefulness of ultrasonography in assessing masses of the neck. Included are five patients with primary tumors, two with metastasis to a cervical node, three with cervical adenitis, two with simple cysts, and two with hematoma related to endarterectomy for occlusive disease of the carotid artery.

Cat-Scratch Disease↗
PubMed1976

Stenosis of the deep femoral artery: an evaluation of the accuracy of single-plane, anteroposterior arteriograms.

Pre-operative evaluation of the deep femoral artery is important in determining surgical treatment of aortofemoral disease. We reviewed 16 years' experience in bilateral aorto-femoral by-pass grafting and found that 63.2% of stenoses of the deep femoral arteries seen at surgery had been missed on conventional antero-posterior arteriograms. These findings demonstrate the inadequacy of a single, antero-posterior projection and the need for supplementary views in assessing lesions of the deep femoral artery.

Arterial Occlusive Diseases↗
PubMed1976

The role of emergency excretory urography in evaluation of blunt, abdominal trauma.

In our hospital, patients seen for blunt, abdominal trauma have an "emergency" urogram. The results of our review of 209 such patients with complete urographic evaluations indicate that (1) the clinical examination, urinalysis, and plain abdominal roentgenogram do not reliably allow one to predict which patients would show urographic abnormalities and (2) the clinical management of these patients is rarely altered by the knowledge of the results of the urogram.

Abdominal Injuries↗
PubMed1976

The value of repeat cerebral arteriography in the evaluation of trauma.

In most patients with head or neck trauma, a single angiogram is sufficient to guide therapy. For those who improve slowly or not at all, however, this is not an adequate basis for diagnosis. Angiography should be repeated after an interval of time to exclude development of a surgically correctable lesion, such as pseudoaneurysm or intracerebral or extracerebral fluid collection.

Adult↗
PubMed1976

The complication rate of catheter angiography by direct puncture through aorto-femoral bypass grafts.

A search of the literature revealed no documentation of the complication rate associated with percutaneous catheterization of aorto-femoral bypass grafts in the arteriographic evaluation of graft patency. The authors compared the complication rates of 29 consecutive arteriograms performed through grafts (Group I) with 40 arteriograms performed on non patients (Group II). Neither group had any significant complications, indicating the safety of percutaneous catheterization of the graft site.

Aged↗
PubMed1976

Arteriographic evaluation of the femoral bifurcation value of the ipsilateral anterior oblique projection.

Accurate preoperative evaluation of the proximal deep femoral artery is critical in proper surgical management of aortofemoral ischemic disease. A review of 116 femoral arteriograms demonstrated significant improvement in visualization of the femoral bifurcation and detection of proximal stenosis of the deep femoral artery when the ipsilateral anterior oblique projection was obtained in addition to the conventional anteroposterior projection.

Angiography↗
PubMed1975

The clinical indications for arteriography in trauma to the extremity. A review of 114 cases.

Analysis of radiographic and physical findings in 114 patients with trauma to an extremity demonstrated that when other physical findings are normal, arteriography is unnecessary. If any physical sign of peripheral vascular injury exists, such as weak or absent pulse, neurologic deficit, bruit, or expanding hematoma, arteriography is essential to define the anatomy and determine the need for surgery.

Aneurysm↗