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Biomedical subjects

M Alam

Publications and source records attributed to M Alam.

At least 73 records · Page 4Linked to original sources

Cardioversion of atrial fibrillation and its effect on right ventricular function as assessed by tricuspid annular motion.

In patients with atrial fibrillation, the reduced right ventricular function determined by tricuspid annular motion before cardioversion returns to normal 1 month after successful cardioversion to sinus rhythm. The simplicity of recording the tricuspid annular motion provides an easy opportunity to assess right ventricular function following electroconversion of atrial fibrillation to sinus rhythm.

Aged↗

Clinical predictors of heart failure in patients with first acute myocardial infarction.

BACKGROUND: The occurrence of heart failure associated with an acute myocardial infarction has a strong adverse effect on long-term morbidity and mortality. The prediction and prevention of heart failure could influence these adverse events. METHODS AND RESULTS: We studied 483 consecutive patients who had their first acute myocardial infarction and who were admitted within 24 hours of the onset of symptoms. Heart failure was defined as the presence of pulmonary rales or an S3 gallop, or the presence of alveolar or interstitial edema by radiograph. Baseline demographic data, determination of peak creatine phosphokinase level, echocardiographic left ventricular ejection fraction, blood pressure, and pulse were obtained. Heart failure occurred in 41.6% (201 of 483) of the patients. We observed a bimodal occurrence of heart failure with an early occurrence at admission in 4% (20 of 483) followed by a second increase beginning after the fourth day of admission in 39% of the remaining patients (181 of 463). Predictors of early heart failure were older age, diabetes mellitus, or previous cardiac symptoms, whereas the predictors of heart failure after the fourth day included the same demographic predictors in addition to a history of hypertension, male sex, increased peak creatine phosphokinase level and heart rate, and decrease in left ventricular ejection fraction. In-hospital death occurred in 5.3% compared with 1.4% (P =.012) in patients who did and did not have heart failure, respectively. The occurrence of heart failure during hospital admission also adversely affected the 18-month follow-up, with 14.9% deaths in the patients with heart failure and 6.4% in those without heart failure (P =.002). CONCLUSION: Heart failure is frequently associated with acute myocardial infarction and occurs with a bimodal distribution and is associated with increased risk of death during hospitalization and during 18 months of follow-up. Predictors of early heart failure include previous medical conditions and age. The second peak occurrence can be predicted by similar characteristics in addition to increased peak creatine phosphokinase level, decreased left ventricular ejection fraction, and increased heart rate.

Aged↗

Spectroscopic characterization of two soluble transducers from the Archaeon Halobacterium salinarum.

In the present study, structural aspects of the two soluble transducers, HtrX and HtrXI, from the archaeon H. salinarum have been examined using UV circular dichroism and steady-state fluorescence spectroscopies. Circular dichroism (CD) data indicate that both HtrX and HtrXI exhibit salt-dependent protein folding. Under low-ionic-strength conditions (0.2 M NaCl or KCl) the CD spectra of HtrXI is similar to that of the Gdn-HCl- or urea-denatured forms and is indicative of random coil structure. In contrast, the CD spectrum of HtrX under low-ionic-strength conditions contains roughly 85% alpha-helical character, indicating a significant degree of folding. Addition of NaCl or KCl to solutions of HtrX or HtrXI results in CD features consistent with predominately alpha-helical character (>95%) for both proteins. In addition, the transition points (i.e., ionic strengths at which the protein converts from random coil to alpha-helical character) are quite distinct and dependent upon the type of salt present (i.e., either NaCl or KCl). Accessibility of tryptophan residues to the solvent was also examined for both HtrX and HtrXI in both folded and unfolded states using KI quenching. The Stem-Volmer constants obtained suggest that the tryptophans (Trp35 in HtrX and both Trp47 and Trp74 in HtrXI) are partially exposed to the solvent, indicating that they are located near the surface of the protein in all three cases. Furthermore, fluorescence quenching with the single Trp mutants Trp74AIa and Trp47AIa of HtrXI indicates different environments for these two residues.

Archaeal Proteins↗

Characteristics of mitral and tricuspid annular velocities determined by pulsed wave Doppler tissue imaging in healthy subjects.

Assessment of myocardial velocities by Doppler tissue imaging is gaining in importance. However, generally accepted reference values are still missing. In this study we examined 62 consecutive healthy subjects (mean age 46, range 22-82 years) by pulsed wave Doppler tissue imaging to characterize the systolic and diastolic velocity profiles of the left and right ventricles. The subjects were divided into 3 different age-groups: group I, younger than 40 years; group II, 40 to 59 years; and group III, 60 years and older. Recordings were made along the long axis in the apical 4- and 2-chamber views by using 4 sites (septal, anterior, lateral, and inferior) at the mitral annulus and 1 site at the tricuspid annulus. Systolic mitral annular velocity (10.3 +/- 1.4 cm/s) correlated strongly with global left ventricular function determined by M-mode echocardiographic mitral annular displacement (r = 0.70, P <.001). The systolic velocity was significantly lower in group III than in group I (9.6 vs 10.8 cm/s, P <.01). A relatively weak, but significant, correlation was found between systolic velocity and the age of the subjects (r = -0.43, P <.001). Mitral annular early diastolic velocity was also lower in group III compared with group I (11.3 vs 17.7 cm/s, P <.001), with a strong correlation with age (r = -0.81, P <.001) and other conventional Doppler diastolic parameters. Both the systolic and early diastolic mitral annular velocities at the septum were lower than at other left ventricular sites. Tricuspid annular systolic velocity (15.2 +/- 1.9 cm/s) was higher than mitral annular systolic velocity (P <.001). Unlike mitral annular velocity, systolic tricuspid annular velocity was not correlated with age. However, the diastolic tricuspid annular velocities correlated well with transtricuspid Doppler diastolic parameters. The method of recording the annular velocities was feasible in all subjects, simple and highly reproducible.

Adult↗

ST-T alternans and myocardial ischemia.

Previous studies using intracoronary electrocardiography have demonstrated that ST-T alternans can develop during standard balloon coronary angioplasty. Total occlusion with a large amount of myocardium in jeopardy is the postulated prerequisite. In this study, the authors used perfusion balloons instead of standard balloons, so coronary perfusion was maintained and ischemia was minimized. Fourteen patients with standard balloon technique and 11 patients with perfusion balloon technique were studied. The ST segment was less elevated during perfusion angioplasty (0.15 +/- 0.05 mV vs 1.04 +/- 0.19 mV, p<0.001). There were six (43%) patients with ST-T alternans with standard balloon technique compared with none in the perfusion balloon group (p<0.001). In this study, the authors found that there was less ischemia, less ST segment elevation, and lack of ST-T alternans on the intracoronary electrocardiogram during perfusion balloon angioplasty. These findings support the postulate that a large amount of ischemic myocardium is a prerequisite for ST-T alternans.

Adult↗

Coronary artery aneurysms, aortic dissection, and hypertension secondary to primary aldosteronism: a rare triad. A case report.

Primary aldosteronism is a relatively uncommon etiology of hypertension. Plasma renin activity is suppressed in the majority of the cases but not always. Plasma renin activity has been associated with increased vascular injury. The occurrence of vascular complications has rarely been reported with low plasma renin activity. The authors report a case of long-standing secondary hypertension due to primary aldosteronism with coronary artery aneurysms and aortic dissection. Diagnosing is important, for therapeutic intervention can be curative.

Adrenal Cortex Neoplasms↗

A study of the cost effectiveness of selective health interventions for the control of intestinal parasites in rural Bangladesh.

The study examined the cost effectiveness of 4 different regimens in reducing the prevalence and intensity of infection of Ascaris lumbricoides, Trichuris trichiura, and hookworm over an 18-mo period in randomized community samples of children aged 2-8 yr living in rural Bangladesh. The household was the unit of randomization in each community. The 4 regimens were (1) only chemotherapy to all household members at the commencement of the study (i.e., at an interval of 18 mo), (2) same as group (1) and regular health education throughout the study period, (3) chemotherapy to all household members at the commencement of the study and subsequent chemotherapy to all children at intervals of 6 mo, and (4) same as group 3 with the addition of regular health education throughout the study period. Health education (through home and school visits and focus group discussions) was aimed at increasing awareness of worm transmission and the disabilities caused by intestinal helminths. Simple ways of improving personal hygiene and sanitation through hand washing, nail trimming, wearing of shoes, and use of a latrine and clean water supplies were encouraged. Because albendazole is a broad spectrum anthelmintic, the cost effectiveness of the 4 interventions were compared by the weighted percentage reduction in prevalence and the weighted percentage reduction in intensities of infection as measured by geometric mean egg loads of all 3 worms combined. The most cost-effective strategy was the single albendazole mass chemotherapy at an interval of 18 mo. The 2 regimens involving health education were the least cost effective.

Albendazole↗

Eruptive paraneoplastic keloids.

We present a 66-year-old woman who developed eruptive keloids in association with endometrial carcinoma in the absence of trauma, surgery, inflammation, or other known preludes to keloid formation. Keloid formation and endometrial carcinoma are both associated with similar cytokine abnormalities and as such, we hypothesize that this is a previously unreported paraneoplastic phenomenon.

Abdominal Muscles↗

Indinavir-related recurrent paronychia and ingrown toenails.

Lamivudine and indinavir are two medications used to treat human immunodeficiency virus (HIV) that have recently been reported to cause paronychia. The nails of the great toes are commonly affected. This is the second report of paronychia and ingrown toenails due to indinavir and the first report of recurrent paronychia and ingrown toenails associated with this drug.

Adult↗

Current topics in nail surgery

BACKGROUND: Nail surgery can be performed in an office-based dermatology practice with a limited amount of specialized equipment and training. Several excellent reviews have been published in recent years that detail the techniques of nail surgery for both the novice and the experienced practitioner. OBJECTIVE: In this article recent developments in nail surgery are discussed. Topics that are treated include the general principles of nail surgery, including epidemiologic issues, studies of nail anatomy, instrumentation, and anesthesia. The reconstruction of injuries and congenital defects involving the nail is explained, and the role of the hand surgeon clarified. Appropriate removal of tumours and cysts is considered, with special attention to the management of malignant lesions. The controversy regarding more or less conservative management of melanonychia striata is addressed, and the need for early diagnosis of subungual melanoma is emphasized. Other topics are surgical management of ingrown nails and onychomycosis. Newer areas of nail surgery, such as laser surgery of the nail, psychodermatology of the nail, and the role of primary care physicians in simple nail surgery are also examined.

Journal Article↗

Conformationally defined retinoic acid analogues. 4. Potential new agents for acute promyelocytic and juvenile myelomonocytic leukemias.

We recently synthesized several conformationally constrained retinoic acid (RA) analogues [8-(2'-cyclohexen-1'-ylidene)-3, 7-dimethyl-2,4,6-octatrienoic acids with different alkyl substituents at 2' (R1) and 3' (R2) positions on the cyclohexene ring] (Muccio et al. J. Med. Chem. 1996, 39, 3625) as cancer chemopreventive agents. UAB8 (R1 = Et; R2 = iPr), which contains sufficient steric bulk at the terminal end of the polyene chain to mimic the trimethylcyclohexenyl ring of RA, displayed biological properties similar to those of RA. To explore the efficacy of this retinoid in acute promyelocytic leukemia (APL) and juvenile myelomonocytic leukemia (JMML), we evaluated UAB8 isomers in in vitro assays which measure the capacity of retinoids to inhibit aberrant myeloid colony growth from blood or bone marrow cells obtained from human JMML patients and in assays measuring the potential of retinoids to differentiate NB4 cells (an APL cell line). Both (all-E)- and (13Z)-UAB8 were 2-fold more active than RA in the NB4 cell differentiation assay; however, only (all-E)-UAB8 had comparable activity to the natural retinoids in the JMML cell assays. These results were compared to the biological effectiveness of a new retinoid, UAB30 [8-(3', 4'-dihydro-1'(2'H)-naphthalen-1'-ylidene)-3,7-dimethyl-2,4, 6-octatrienoic acid], which had different nuclear receptor binding and transactivational properties than UAB8. Relative to (all-E)-RA and (all-E)-UAB8, (all-E)-UAB30 bound well to RARalpha but did not activate transcription-mediated RARalpha homodimers, even though it was effective in RARbeta- and RARgamma-mediated transactivational assays. In APL assays, this retinoid had much reduced activity and was only moderately effective in JMML assays and in cancer chemoprevention assays.

Animals↗

The clinical implications (or lack thereof) of vegetations detected by echocardiography in patients not thought to have endocarditis.

BACKGROUND: The clinical impact of echocardiographic demonstration of a vegetation (Veg) in patients in whom infective endocarditis (IE) is not suspected has not previously been analyzed. HYPOTHESIS: In this study, an echocardiographic database was interrogated to test whether discovery of a vegetation by echocardiography should result in treatment for endocarditis if IE is not suspected. METHODS: In all, 2,750 serial transthoracic echocardiograms (TTE) were reviewed to generate a list of reports containing the word Veg or thickening (Thk). A chart review of cases identified the impact the report had on patient management. To analyze reader bias due to echocardiographic requests, stating "rule out Veg or IE" as the reason for the study, an additional 1,000 serial TTE requests were segregated into two groups with and without this term. The incidence of the terms Veg or Thk in TTE reports of these groups was tabulated. RESULTS: Of 2,750 reports, 20 contained the word Veg. Blood cultures were drawn in 16 of 20, with 7 of 16 being positive. Therapy for IE was initiated in 5 of 7 patients with positive cultures. Of 1,000 requests reviewed in the second phase, 24% of those with rule out Veg as the indication for TTE (n = 29) had Veg and 7% had Thk, while in 971 cases with other indications for TTE 0.2% had Veg and 9.3% had Thk. CONCLUSIONS: Clinicians disregard TTE demonstration of Veg if clinical suspicion for IE is low. It is not clear whether the initial echo request biases the interpretation.

Case-Control Studies↗