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Biomedical subjects

D B Rao

Publications and source records attributed to D B Rao.

At least 19 recordsLinked to original sources
PubMed2001

Free radical generation in the cochlea during combined exposure to noise and carbon monoxide: an electrophysiological and an EPR study.

Ototoxicity following combined exposure to noise and carbon monoxide (CO) is known to result in more severe permanent threshold shifts than exposure to noise alone. We have previously demonstrated that such potentiation of noise-induced auditory impairment by CO can be prevented by the administration of a nitrone spin-trapping agent. Although such protection implicates injury via free radical pathways, drug-induced protection does not provide direct evidence for the presence of free radicals in the cochlea. The objective of this study was to demonstrate the actual presence of nitrone spin adducts in the cochlea following simultaneous exposure to noise and CO. Using electrophysiological end-points, the protective effects of the nitrone spin-trapping agent alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) were assessed following combined exposure of adult male Long Evans hooded rats to noise and CO. In addition, an ex-vivo evaluation of POBN spin adducts was done by electron paramagnetic resonance spectroscopy (EPR). The noise used was octave band noise with center frequency 13.6 kHz at 100 dB(Lin) for a duration of 2 h. The level of CO used was 1200 ppm. Electrophysiological results demonstrate that POBN protects against combined exposure to noise plus CO. The EPR study demonstrates POBN spin adducts in the cochleae of animals exposed to noise plus CO. Therefore, this study provides evidence to the hypothesis that ototoxicity due to noise plus CO exposure is mediated via free radicals.

Animals↗
PubMed2001

Caries prevalence amongst handicapped children of South Canara district, Karnataka.

This epidemiological investigation was carried out among 524 handicapped children in the age group of 3-30 years, attending 8 different non-residential special schools in South Canara district, Karnataka. The examination procedure and criteria were those recommended by W.H.O. in 1997. The total caries prevalence was found to be 71.56%. The mean deft in the primary dentition was found to be 3.06 +/- 3.14. The mean deft and DMFT in the mixed dentition were 3.32 +/- 2.82 and 1.14 +/- 1.08 respectively. The mean DMFT in the permanent dentition was 4.51 +/- 3.17. The prevalence of dental caries was higher in the mentally subnormal and handicapped children. The decayed component constituted the majority of the dental caries index. Lack of conservative approach to the treatment had been confirmed in the study.

Adolescent↗
PubMed2000

Increased noise severity limits potentiation of noise induced hearing loss by carbon monoxide.

This study evaluates the influence of noise intensity and duration on auditory dysfunction due to simultaneous exposure to noise and carbon monoxide (CO). Previous studies have demonstrated that CO potentiates noise induced hearing loss (NIHL). It is not known whether auditory dysfunction due to combined exposure parallels impairment due to noise alone. Based on the 5 dB exchange rate between noise intensity and exposure doubling time, equivalent noise exposure conditions were used. Long Evans hooded rats were divided into groups that received noise alone (95, 100 and 105 dB SPL), and noise plus CO (1200 ppm), for durations of 4, 2 and 1 h, respectively. Controls were exposed to air or CO alone. Thresholds were evaluated 4 weeks later using an electrophysiological endpoint, the compound action potential threshold. Results demonstrate that the 5 dB exchange rate is not conserved under the conditions and subjects used. Moreover, dysfunction due to combined exposure did not parallel dysfunction due to noise alone. Further, although an increase in exposure duration results in increased auditory dysfunction, no further potentiation of NIHL by CO is observed. This suggests that at increasing noise severity, dysfunction due to combined exposure is limited by impairment due to noise alone.

Acoustic Stimulation↗
PubMed1978

Multiple primary malignancy in the elderly.

The longer a patient lives, the more predisposed he is to become host to primary malignant neoplasms at various sites. Hence the importance of follow-up clinics in long-term care facilities. Data on multiple malignancies at Oak Forest Hospital are presented. Among 34 such patients (average age, 72 years), 28 had malignant lesions at two primary sites, and 6 at three primary sites.

Age Factors↗
PubMed1977

The second heart sound in old age.

The second heart sound was studied by phonocardiography and carotid tracings in 103 elderly subjects without overt evidence of heart disease. Their ages ranged from 60 to 99 years. A normal type of splitting was found in 55.3%, and a single sound in 41.7%. The difference between these percentages and those found in 60 normal younger persons was not significant. Thus, a single second sound should not be considered a typical finding in old age. However, a reverse type of splitting, noted in only 3 patients, should be regarded as evidence of severe latent heart disease.

Adult↗
PubMed1977

Cyclandelate in the treatment of senile mental changes: a double-blind evaluation.

The treatment of cerebrovascular insufficiency and its many symptoms in the ever-increasing numbers of the aged, is of major concern to physicians engaged in such care. Despite past skepticism as to the degree of efficacy of cerebral vasodilators, there is renewed interest in this form of therapy. Our investigation was designed to assess the effectiveness of cyclandelate, under strict double-blind conditions, in 58 geriatric patients. The cyclandelate and placebo groups (32 and 26 patients respectively) received either 1,600 mg/day of cyclandelate in fractional doses, or identical-appearing placebo capsules--over a period of 12 weeks. During the initial examination and every four weeks thereafter, patients were assessed for possible changes in vital signs and for evidence of adverse reactions. In addition, the Sandoz Clinical Assessment-Geriatric (SCAG) and the Nurses Observation Scale for Inpatient Evaluation (NOSIE) were completed, with particular attention to symptom clusters. A final global assessment was made in which the physician rated patients according to their overall clinical condition. The results of our study and analysis indicate that cyclandelate is a safe and effective agent for treating certain symptoms of senility in properly selected patients, provided the therapy is carried on for at least eight weeks and, if indicated, for a longer period. Clinical evidence suggests that the prudent use of this drug may definitely delay deterioration.

Aged↗
PubMed1977

What is "normal" blood pressure in the aged?

Blood pressure was studied in two groups of institutionalized subjects ranging in age from 50 to over 100 years. The first group comprised 199 selected normal subjects; subjects with any disease, including systemic hypertension, were excluded. The second group consisted of 947 unselected subjects; those with acute illness were excluded. In the first group, systolic pressure increased slightly, but diastolic pressure did not change with increasing age. The blood pressures were still within the limits that were considered normal for younger persons. In the second group, both the systolic and the diastolic pressures progressively decreased with age, so that the former fell below normal limits.

Aged↗
PubMed1976

Incidence of murmurs in the aging heart.

One hundred patients aged 60 or older were studied clinically after excluding those with cardiac enlargement, definite valvular lesions or electrocardiographic (ECG) evidence of left ventricular hypertrophy. In 30 of the the 100 patients a significant systolic murmur was heard on auscultation. Phonocardiograms (PCGs), mitral echograms and pulse tracings were obtained in 28 of these 30 patients (2 had died meanwhile), and the ECGs and chest roentgenograms were reviewed. In 23 PCG patients there was an early or midsystolic murmur, best recorded at the base of the heart and often transmiteed to the apex. Mitral valve echograms and carotid and jugular pulse tracings were normal in all cases. Chest roentgenograms revealed aortic enlargement in 83 percent of the 23 patients. In the elderly with no evidence of organic heart disease, a basal systolic murmur is probably an aortic flow phenomenon caused by either moderate aortic dilatation or minimal fibrotic fusion of one or more commissures of the aortic valve.

Age Factors↗
PubMed1976

Importance of aortic dilatation in the genesis of the innocent systolic ejection murmur of the aged.

Aortic systolic murmurs and aortic dilatation were studied in a randomized sample of 100 hospital patients over the age of 60. Clinical, phonocardiographic, radiologic and carotid-pulse data provided the basis for graphic characterization of the murmurs. Senile aortic dilatation was common (66 patients). In a high percentage (39 patients), dilatation of the ascending aorta (and sometimes of the arch) was associated with an aortic systolic murmur. The "innocent" type was always associated with aortic dilatation. This "innocent murmur of the aged", even though caused by structural alterations, should be considered in the same light as the "innocent murmur of children", as it is not associated with dynamic embarrassment of the circulation.

Aged↗
PubMed1976

Tachyarrhythmias in old age.

The electrocardiograms of 1,171 patients above the age of 65 in a predominantly geriatric institution were reviewed to determine the incidence of tachyarrhythmias. Data on the overall incidence and the individual types of arrhythmias are presented. Atrial fibrillation was the most common arrhythmia observed, followed by atrial flutter and supraventricular tachycardia. Atrial fibrillation often was associated with other evidence of myocardial damage. The significance of sinus bradycardia and grade I A-V block in the pathogenesis of atrial fibrillation and the significance of the tachyarrhythmias are discussed.

Aged↗
PubMed1975

Correlates of the echocardiographic waves of the mitral valve in normal subjects of various ages.

A cardiographic study was performed on 71 subjects including 14 children, 42 young and middle-aged adults, and 15 old persons without evidence of heart disease. The echocardiogram of the mitral valve was recorded in the A mode by an analog method and was compared with the electrocardiogram, phonocardiogram, apex cardiogram, and carotid and jugular tracings, simultaneously obtained. The intervals between the various waves recorded by these methods were measured and the results were compared with those reported in the literature. A comparison of the duration of the intervals in the various age groups showed statistically significant differences. In particular, the intervals between the second heart sound and the peak of the E-wave and the E-F intervals in the echogram were longer in adults than in children and also longer in old persons than in younger adults. This important age difference should always be taken into account before attributing any echocardiographic deviations to disease.

Adolescent↗
PubMed1975

Collagenase in the treatment of dermal and decubitus ulcers.

The current management of decubitus ulcers, factors in wound healing and the role of enzymes in treatment are discussed. The therapeutic benefits of collagenase (Santyl) ointment in 21 patients are described, supplemented by serial color photographs. Statistical evidence is provided for the conclusion that collagenase ointment is an excellent adjunct to therapy.

Adult↗
PubMed1975

Ventricular relaxation and mitral opening time in various ventricular conditions of old age.

This phonocardiographic-echocardiographic study was based on measurement of the interval between the aortic component of the second sound (IIA) and the peak of the E wave of the mitral echogram. The study was performed in 20 cases of left bundle branch block (LBBB), 10 cases of right bundle branch block (RBBB), 10 cases of old myocardial infarct (MI), and 10 cases of systemic hypertension (HY). All patients were above 60 years of age, and their data were compared with those of old persons without evidence of heart disease serving as controls. The IIA-E interval was found markedly prolonged in LBBB, less prolonged in MI and RBBB, and was shortened in HY. A dynamic analysis revealed that this interval results from the isovolumic relaxation period (IRP) of the left ventricle plus the "opening time" of the mitral valve. The changes observed were explained as resulting from a modification of the IRP that should be correlated with a similar modification of the isovolumic contraction time. Myocardial fibrosis would cause prolongation of IRP through structural lesions while hypertension would cause abbreviation of IRP through hormonal effects modifying both contraction and relaxation.

Aged↗