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Biomedical subjects

E Henderson

Publications and source records attributed to E Henderson.

At least 127 records · Page 7Linked to original sources

Atenolol and celiprolol for stable angina pectoris.

Once-daily atenolol and celiprolol were compared in a placebo-controlled crossover study of 16 patients with stable angina pectoris. Atenolol and celiprolol equally and significantly reduced frequency of angina and electrocardiographic evidence of cardiac ischemia. Celiprolol, however, produced less suppression of the double product at 1 mm of ST-segment depression than atenolol, suggesting that actions other than reduction of heart rate may contribute to its antianginal efficacy.

Adrenergic beta-Antagonists↗

Iodine-123 phenylpentadecanoic acid and single photon emission computed tomography in identifying left ventricular regional metabolic abnormalities in patients with coronary heart disease: comparison with thallium-201 myocardial tomography.

Iodine-123 phenylpentadecanoic acid (IPPA) is a synthetic long chain fatty acid with myocardial kinetics similar to palmitate. Two hypotheses were tested in this study. The first hypothesis was that IPPA imaging with single photon emission computed tomography (SPECT) is useful in the identification of patients with coronary artery disease. Fourteen normal volunteers (aged 27 +/- 2 years) and 33 patients (aged 54 +/- 11 years) with stable symptomatic coronary artery disease and at least one major coronary artery with luminal diameter narrowing greater than or equal to 70% were studied with symptom-limited maximal exercise testing. The IPPA (6 to 8 mCi) was injected 1 min before the termination of exercise, and tomographic imaging was performed beginning at 9 min and repeated at 40 min after the injection of IPPA. Nine of the normal volunteers and 13 of the patients had a second examination performed at rest on another day. Using the limits of normal as 2 SD from the normal mean values, 27 of the 33 patients with coronary artery disease demonstrated abnormalities in either the initial distribution or the clearance of IPPA, or both. Nineteen of the 33 patients had a maximal variation of activity distribution of greater than or equal to 25% on the 9 min IPPA images. Twenty-two of the 33 patients had a maximal variation in IPPA washout greater than 17% and 17 had a washout rate less than or equal to 2%. There was good agreement between the location of significant coronary artery stenoses and abnormalities in the initial distribution and clearance of IPPA. The second hypothesis tested was that IPPA imaging is as or more sensitive and, therefore, complementary to thallium-201 imaging in the identification of exercise-induced ischemia in patients. Twenty-five of the 33 patients underwent both thallium-201 and IPPA tomographic imaging after symptom-limited maximal exercise testing. The amount of exercise performed by each patient during both studies was similar. Twenty-one of the 25 patients had abnormal IPPA tomographic studies, whereas 18 had abnormal thallium-201 tomographic studies (p = NS). The results of this study suggest the following conclusions: 1) iodine-123 phenylpentadecanoic acid imaging using single photon emission computed tomography and exercise provides a sensitive and relatively noninvasive method for identifying abnormalities in myocardial metabolism associated with significant coronary artery stenoses, and 2) iodine-123 phenylpentadecanoic acid is at least as sensitive as thallium-201 for this purpose using tomographic imaging and exercise testing.

Adult↗

Electrocardiographic diagnosis of left ventricular hypertrophy: influence of body build.

1. The sensitivity and specificity of four sets of electrocardiographic criteria for detection of left ventricular hypertrophy were evaluated in an echocardiographic study of 100 hypertensive patients. 2. All criteria gave reasonable specificity (87-94%) but poor sensitivity (39-52%). 3. When non-obese and obese patients were studied separately, criteria based on chest lead voltages were more sensitive than limb lead criteria for detection of left ventricular hypertrophy in non-obese subjects; however, the reverse was true in obese hypertensive patients, where criteria based on limb lead voltages were more sensitive than chest lead voltage criteria. 4. These data suggest that stratification of subjects by body build might improve the diagnostic performance of the electrocardiogram for detection of left ventricular hypertrophy.

Cardiomegaly↗

Angina pectoris during exercise--relationship to coronary anatomy and myocardial function.

We studied 34 patients with proven coronary heart disease to determine whether the presence or absence of angina pectoris during exercise testing was associated with greater disease, ST segment depression or fall in left ventricular ejection fraction. Angina pectoris was the limiting symptom in 19 and fatigue/breathlessness in 15 patients. Exercise time [421(31) vs. 455(64) s], ST depression [1.4(0.3) vs. 1.1(0.3)mm], fall in left ventricular ejection fraction [13(2) vs. 12(2)] and coronary score and fall in left ventricular ejection fraction [15(2) vs. 8(3), P less than 0.02]. The degree of ST segment depression correlated with the coronary score (r = 0.6) and fall in left ventricular ejection fraction (r = 0.5). ST segment depression but not angina pectoris during exercise predicted the extent of disease and its functional consequences.

Angina Pectoris↗

Developing POPTRAN, a population modelling package.

"Collaboration between subject matter specialists, computer programmers and educational technologists has resulted in the reproduction of POPTRAN, a computer assisted learning package designed to teach the basic concepts of population studies. Its evaluation in developing countries, with both naive and specialist users, and subsequent revision, has produced a package of both academic quality and teaching effectiveness."

Demography↗

Vincristine and prednisone prolong the survival of patients receiving intravenous or oral melphalan for multiple myeloma: Cancer and Leukemia Group B experience.

A total of 589 patients with previously untreated multiple myeloma were randomized to receive daily oral melphalan, pulse-dose intravenous (IV) melphalan, carmustine (BCNU), or lomustine (CCNU). All patients received an initial tapering course of prednisone (Pred). During week 22 (day 154), patients were randomized to receive or not to receive additional therapy with vincristine (VCR) (1 mg/m2) and prednisone (0.6 mg/kg/d for seven days) at 8-week intervals. The influence of VCR/Pred was determined in 302 patients who remained on study beyond 22 weeks after initial therapy. VCR/Pred converted a significant percentage of nonresponders to responders in patients treated with melphalan (55% v 19%, P = .002), but not in patients treated with a nitrosourea (48% v 23%, P = .06). Survival beyond week 22 was significantly longer following the addition of VCR/Pred in patients receiving melphalan (median, 35.3 months v 27.0 months; P = .003) but not in patients receiving BCNU or CCNU (median, 28.1 months v 26.2 months; P = .91). These differences were seen both for oral and IV melphalan. A trend for beneficial effect of VCR/Pred was definitely seen in the good-risk patients (P = .03) but only suggestive for poor-risk patients (P = .12). Following adjustment for VCR/Pred effects, there were no differences in the survival of patients receiving any of the four initial treatments.

Antineoplastic Combined Chemotherapy Protocols↗

Effect of alpha-interferon therapy on bone marrow fibrosis in hairy cell leukemia.

Iliac crest trephine biopsy specimens from 16 patients treated with recombinant alpha 2-interferon (alpha-IFN) for hairy cell leukemia (HCL) were examined for reticulin and collagen content. These data were compared with the hairy cell index (HCl), the proportion of hairy cells to the overall cellularity of the bone marrow. Specimens were studied immediately before alpha-IFN therapy, at 6-month intervals during, and in six patients 6 months after cessation of therapy. All patients presented with increased bone marrow fibrosis ranging from focally increased reticulin to a diffuse increase in both reticulin and collagen content. This fibrosis was observed to decrease during alpha-IFN therapy inasmuch as the hairy cell population was diminished in the bone marrow in 13 patients. Regression analysis of HCl v bone marrow fibrosis showed a positive correlation (r = .73, P less than .02). Six patients demonstrated a reduction in bone marrow reticulin and collagen to normal levels during alpha-IFN therapy. Two of six patients demonstrated increased bone marrow fibrosis and HCl 6 months after cessation of alpha-IFN therapy. Three of 16 patients exhibited no decrease in bone marrow reticulin content during therapy despite a decreased bone marrow hairy cell population.

Adult↗

Telomeric DNA oligonucleotides form novel intramolecular structures containing guanine-guanine base pairs.

Structural properties of DNA oligonucleotides corresponding to the single-stranded molecular terminus of telomeres from several organisms were analyzed. Based on physical studies including nondenaturing polyacrylamide gel electrophoresis, absorbance thermal denaturation analysis, and 1H and 31P nuclear magnetic resonance spectroscopy, we conclude that these molecules can self-associate by forming non-Watson-Crick, guanine.guanine based-paired, intramolecular structures. These structures form below 40 degrees C at moderate ionic strength and neutral pH and behave like hairpin duplexes in nondenaturing polyacrylamide gels. Detailed analysis of the hairpin structure formed by the telomeric sequence from Tetrahymena, (T2G4)4, shows that it is a unique structure stabilized by hydrogen bonds and contains G residues in the syn conformation. We propose that this novel form of DNA is important for telomere function and sets a precedent for the biological relevance of non-Watson-Crick base-paired DNA structures.

Animals↗

Ventricular arrhythmias in patients with hypertensive left ventricular hypertrophy.

In patients with hypertension, a pattern of left ventricular hypertrophy on the electrocardiogram is associated with a risk of sudden death in excess of the risk attributable to hypertension alone. We therefore investigated the frequency of complex ventricular arrhythmias by means of 48-hour ambulatory electrocardiographic monitoring in 100 treated hypertensive patients, of whom 50 had electrocardiographic evidence of left ventricular hypertrophy and 50 did not, and in 50 normotensive controls. The groups were matched for age, sex, and smoking habits, and the two hypertensive groups were matched for blood-pressure levels before and after antihypertensive therapy. Nonsustained ventricular tachycardia, defined as greater than or equal to 3 complexes at a rate greater than or equal to 120 beats per minute, occurred in 14 (28 percent) of the 50 patients with an electrocardiographic pattern of left ventricular hypertrophy, in 4 (8 percent) of the 50 patients without hypertrophy (P less than 0.05), and in 1 (2 percent) of the control subjects. Eight of the 50 patients (16 percent) with hypertrophy had episodes of nonsustained ventricular tachycardia longer than 5 complexes, whereas no patients without hypertrophy and no controls had such episodes. The group with nonsustained ventricular tachycardia was characterized by a high left ventricular mass on echocardiography and a high prevalence of ST-T abnormalities on electrocardiography. Ventricular tachycardia was not closely related to blood-pressure levels, nor was it associated with diuretic therapy or hypokalemia. The clinical importance of these arrhythmias is uncertain. Nevertheless, our data suggest that complex ventricular arrhythmias occur commonly in hypertensive patients with left ventricular hypertrophy and may contribute to the higher incidence of sudden death in these patients.

Cardiomegaly↗

An autopsy study of 1206 acute and chronic leukemias (1958 to 1982).

Autopsy data on 1,206 children and adult patients with acute myelocytic leukemia (AML) (585), chronic granulocytic leukemia (CGL) (204), acute lymphocytic leukemia (ALL) (308), and chronic lymphocytic leukemia (CLL) (109) obtained from 1958 to 1982 were reviewed. This analysis has shown that, whereas the proportion of patients with residual AML at any anatomic site decreased significantly and uniformly over the entire study period, significant corresponding decreases in patients with CGL and ALL occurred only since 1976 and 1978, respectively. No significant corresponding decreases were noted in patients with CLL at any time. Significant decreases were also noted over time in the rates of extramedullary site involvement by AML, CGL, and ALL. Whereas the lymphoreticular organs, kidneys, adrenals, and pituitary were most often involved at autopsy by CLL, the testes, leptomeninges, dura mater, uterus, large bowel, and pancreas were most often involved by ALL. In general, patients with AML and CGL showed the lowest relative rates of involvement of the various organs by leukemia during the 24-year period. Whereas patients with AML and ALL showed significant decreases in the rates of involvement of nearly all anatomic sites during the most recent study periods, those with CGL and CLL showed corresponding decreases in only a few organ sites. The lower rates of organ involvement in patients with AML and ALL attest to the more aggressive eradication of leukemic cells by therapeutic regimens in these diseases over time. In particular, the significant decrease in the rate of meningeal involvement by ALL during the most recent period is probably attributable to central nervous system prophylaxis.

Adolescent↗

Phase I clinical trial of 1-(2-[2-(4-pyridyl)-2-imidazoline-1-yl]-ethyl)-3-(4-carboxy-phenyl) urea (CGP 15720A).

A phase I clinical trial of the intravenous administration of a novel pyridyl imidazoline ethyl carboxy phenyl urea was carried out in 42 patients with advanced solid tumors. Five schedules were evaluated: I, daily X 5; II, daily X 10; III, daily X 15; IV, continuous infusion for 5 days; V, continuous infusion for 7 days. Toxicity was not seen in schedule I (maximum dose 3 g/m2/day) and was minimal in schedule IV (6 g/m2/day). In schedule II it was seen at 2 and 3 g/m2/day, in schedule III at 2 g/m2/day and in schedule V at 6 g/m2/day. Dose-limiting toxicity consisted of a syndrome of lethargy and fatigue. There were no definitely drug-related changes in hematologic or serum chemistry parameters. No responses were seen, but relief of pain in three patients with prostate cancer was noted. Pharmacokinetics indicate a short half-life, limited volume of distribution, and rapid renal clearance. The recommended dose for phase II studies is 3 g/m2/day X 10 or 2 g/m2/day X 15 days.

Adult↗

Gold 195m in the assessment of the cold pressor test by first pass radionuclide ventriculography.

First pass radionuclide ventriculography was performed with gold 195m in a sequential evaluation of left ventricular ejection fraction during cold pressor stimulation. We studied 10 normal controls, 10 patients with angina pectoris who had proven coronary artery disease and normal left ventricular function during contrast angiography and 10 patients with dilated cardiomyopathy with normal coronary arteries and impaired left ventricular function at contrast angiography. Mean resting ejection fraction was similar in controls and patients with coronary heart disease (57 +/- 2 vs 58 +/- 3) but was significantly lower in the cardiomyopathic subjects (27 +/- 4, P less than 0.001). After 30 seconds cold pressor stimulation, mean left ventricular ejection fraction fell in the normal controls (57 +/- 2 to 52 +/- 2, P less than 0.05) but was unchanged in those with coronary heart disease and dilated cardiomyopathy (58 +/- 3 to 55 +/- 3 and 27 +/- 4 to 24 +/- 4, both NS). No further significant change occurred after 2.5 minutes stimulation (53 +/- 1, 58 +/- 3 and 23 +/- 3, respectively). There was no difference in the pattern of left ventricular ejection fraction response between the groups. Six controls, 4 patients with coronary heart disease and 4 patients with dilated cardiomyopathy had a significant fall in left ventricular ejection fraction and 4, 5 and 6, respectively, developed a new or further deterioration in regional wall motion. Thus neither changes in regional wall motion nor left ventricular ejection fraction response distinguished either patient group from the normal controls. We do not recommend cold pressor stimulation as a diagnostic test for coronary heart disease.

Adult↗

The association of bacteriuria with resident characteristics and survival in elderly institutionalized men.

Ninety-one elderly male residents of a skilled nursing facility were classified as nonbacteriuric (41%), intermittently bacteriuric (34%), or continuously bacteriuric (25%) on the basis of urine cultures obtained over a 3-year period. Bacteriuric and nonbacteriuric residents were similar in age, number of diagnoses and medications, and mobility. However, bacteriuric residents were more frequently confused or demented, whether continuously bacteriuric (78%) or intermittently bacteriuric (62%) compared with nonbacteriuric residents (42%) (p less than 0.04). In addition, bacteriuria was significantly associated with incontinence of bladder (96% of continuous, 66% of intermittent, and 25% of nonbacteriuric; p less than 0.001) and bowel (52%, 39%, and 5.5%, respectively; p less than 0.002). At 6 years of follow-up there were no differences in survival among the three groups. Urinary tract infection caused or contributed to only two (2.9%) deaths. Thus, in this population, bacteriuria was associated with higher functional disability but not with increased mortality.

Aged↗

DNA hybridization electron microscopy: ribosomal RNA nucleotides 1392-1407 are exposed in the cleft of the small subunit.

The ribosomal sequence corresponding to Escherichia coli 16S rRNA nucleotides 1392-1407 (the "1400 region") is phylogenetically conserved and is in a functionally important region of the subunit. Using the technique of DNA hybridization electron microscopy, we have mapped this sequence on the surface of the small ribosomal subunit. In this procedure a synthetic oligodeoxynucleotide probe, complementary to a specific rRNA sequence and carrying an attached marker molecule, is hybridized to ribosomal subunits in order to determine the dimensional site of attachment. In the E. coli ribosome, the 1400 region is located at the level of the neck, near the cleft and most likely on the head of the small subunit. The related sequence in yeast 18S rRNA, nucleotides 1618-1633, is located in the topological equivalent of the E. coli site. The location of this region, which has been crosslinked to the anticodon of a peptidyl-site-bound tRNA, indicates that this part of the cleft of the small subunit has a similar three-dimensional organization in phylogenetically diverse organisms and suggests that it is the site of the codon-anticodon interaction.

Avidin↗

Digital coronary roadmapping as an aid for performing coronary angioplasty.

In an attempt to improve visualization of the position of the guidewire and dilatation balloon during coronary angioplasty, a method was developed called digital coronary roadmapping. With this method a digitally acquired coronary angiogram is interlaced with the live fluoroscopic image of the guidewire and balloon catheter. The digital coronary angiogram is superimposed at the same magnification and radiologic projection as the live fluoroscopic image onto the video monitor above the catheterization table. The digital roadmap image thus provides immediate feedback to the angiographer to assist in directing the guidewire into the appropriate coronary artery branch and to help in placement of the balloon so that it straddles the site of stenosis.

Adult↗