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Biomedical subjects

B Ramamurthi

Publications and source records attributed to B Ramamurthi.

At least 19 recordsLinked to original sources
PubMed1995

Mentality and behaviour in India.

Based on a historical survey of the origins and development of the Hindu religion and its absorption of Buddhism the author outlines that tolerance, gentle behaviour, profound optimism and a lack of obsession with time are the main features of Indian mentality and behaviour. But with industrial revolution, urbanisation and population explosion many old values have been eroded and even aggression of different degrees found its way into the Indian psyche.

Buddhism↗
PubMed1995

Cystic meningiomas.

BACKGROUND: Meningiomas are generally solid tumors and are easily diagnosed by CT scans and MRI scans. Rarely are these tumors associated with cysts that can cause a confusion in the pre- and intraoperative diagnosis. Cysts associated with meningiomas may be intratumoral or peritumoral. METHODS: The authors conducted a retrospective study of the seventeen meningiomas, out of a total number of 232, which were associated with cysts. The cysts were classified based on their relationship to the tumor. The patients' sex, age group, location of the tumor, and pathological type of tumor were also analyzed. RESULTS: The 17 cases of cystic meningioma formed 7.3% of the meningiomas seen between 1984 and 1993. Eleven of these were intratumoral and 6 peritumoral. One case had both intra- and peritumoral cysts. The tumors were found mostly in the fourth and fifth decades of life. Histologically, all the peritumoral cysts except one were associated with meningotheliomatous meningiomas. Tumors with peritumoral cysts were more common in males. Intratumoral cysts, more common in females, were angioblastic or meningotheliomatous on histopathology. Only one case was an anaplastic meningioma. CONCLUSION: Cysts associated with meningiomas, although uncommon, are certainly not rare. The peritumoral and the intratumoral cysts form distinct subtypes needing separate consideration. Cystic meningiomas are only rarely malignant.

Adult↗
PubMed1995

The continuing challenge of acoustic neurinomas (1949-1993).

Experience gained in the treatment of acoustic neurinomas over a period of 43 years is presented. This is divided into three eras based on the prevailing knowledge and techniques. Advances in diagnosis, anaesthesia and microsurgical techniques have reduced the mortality to 4% in large tumours and to less than 1% in small tumours. With large tumours, facial nerve preservation has been possible only in 20% of patients. Large tumours continue to predominate, thus providing a formidable challenge. Saving life and the functions of the lower cranial nerves still form the main goal in the majority of patients who come with large tumours.

Cerebellum↗
PubMed1995

The fourth state of consciousness: the Thuriya Avastha.

Present day neurophysiology stops with attributing thinking processes as the highest level of function of the brain. It has been common knowledge to oriental thinkers for many centuries, that there are many further states of the human mind, culminating in the state of thoughtless awareness; the fourth state of consciousness. This state must have a physiological basis. The complicated structure of the brain, the extravagant abundance of neural and glial elements in the brain, the infinite possibilities of synaptic junctions and synaptic transmission, and the multitude of neurotransmitters and neuromodulators; all these point to the definite possibility of a much greater level of performance and achievement for the human brain than has been apparent so far. Not only the theories but also the experience of Eastern seers have shown that the brain can transcend the boundaries of logic and reason, and experience states of awareness, commonly unrecognized. In the past few decades, knowledge about the functioning of the human brain has been growing exponentially and scientists of diverse disciplines are concentrating on unraveling its mysteries. It is necessary for scientists to investigate this state with all available tools and find the neurophysiological basis of this state.

Awareness↗
PubMed1993

Aphasia in bilinguals.

The neurophysiological and the neurolinguistic basis of multilingualism is not yet fully elucidated. A study of the occurrence of aphasia in multilingual patients and the pattern of recovery may help to clarify some unsolved problems. For e.g. is the ability to use a second language stored in a different area of the left hemisphere and what is the extent of involvement of the right hemisphere in language skills? When recovery from aphasia occurs, what factors determine the rate of recovery of different languages and the priorities of recovery? To understand some of the problems, a study of aphasia in multilinguals was conducted in Madras, South India, where multilingualism is common. 88 patients were studied with 40 healthy controls, using standard protocols. It was found that the pattern of recovery was dispersed widely in time, rate, level, degree and between the languages known. No support was obtained for the notion that the patients' mother tongue recovers first, nor was support found for the importance of language proficiency viewed globally. Evidence was found that the languages in which routine thinking, mental calculations and praying were carried out were the ones most resistant to damage in brain insults. It is interesting that these functions are all highly overlearned, acquired early in life and used frequently over the course of many years. Another observation made was that the incidence of crossed aphasia was fairly high, in both uni- and multi-linguals, with the latter showing a slightly higher incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The changing face of tuberculomas.

Tuberculomas of the brain continue to be prevalent in all the developing countries of Asia, Africa, South American and Europe and seem to be making a comeback in the richer nations of the West. They pose a challenge to the neurosurgeon, in spite of the advances that have been made in the diagnosis of these lesions and in the available therapeutic regimes. During the last decade, computed tomographic (CT) scan has facilitated early diagnosis of tuberculomas at a stage when the lesions are small and antituberculous therapy (ATT) has been found beneficial in the majority of patients. Those lesions that do not respond need change in the ATT regimen and addition of steroids. Some lesions tend to disappear by themselves after a few weeks and probably are not tuberculous in nature. Some continue to grow in spite of ATT, probably due to drug resistance and require surgery, and some turn out to be gliomas. As it is not possible to differentiate between glioma or tuberculoma from CT morphology alone, and as stereotactic biopsy can be expensive, it is worth a trial with ATT, reserving surgery only to those which continue to grow inspite of ATT.

Humans↗
PubMed1990

Vector quantization for compression of multichannel ECG.

We propose a scheme based on vector quantization (VQ) for the data-compression of multichannel ECG waveforms. N-channel ECG is first coded using m-AZTEC, a new, multichannel extension of the AZTEC algorithm. As in AZTEC, the waveform is approximated using only lines and slopes; however, in m-AZTEC, the N-channels are coded simultaneously into a sequence of N + 1 dimensional vectors, thus exploiting the correlation that exists across channels in the AZTEC duration-parameter. Classified vector quantization (CVQ) of the m-AZTEC output is next performed to exploit the correlation in the other AZTEC parameter, namely, the value-parameter. CVQ preserves the waveform morphology by treating the lines and slopes as two perceptually-distinct classes. Both m-AZTEC and CVQ provide data-compression and their performance improves as the number of channels increases. Moreover, the final output differs little from the AZTEC output and hence ought to enjoy the same acceptability.

Algorithms↗
PubMed1989

Intracerebral hematoma following evacuation of chronic subdural hematoma.

The prognosis after evacuation of a chronic subdural hematoma is generally good, yet occasionally post-operative complications do occur. Intracerebral hematoma following such evacuation is rare and two cases are reported. It is suggested that this complication could be due to the disturbances of intracerebral vascular homeostasis occurring after rapid evacuation of subdural hematomas where there has been a large shift of the brain stem.

Aged↗
PubMed1989

International neurosurgery: neurosurgical training and practice in India, Korea, Japan, and Australasia.

During the 1985 annual meeting of the Congress of Neurological Surgeons in Honolulu, neurosurgical training and practice in India, Korea, Japan, and Australasia were discussed at the International Committee symposium. This article summarizes the information presented. India has about 300 neurosurgeons for a population of 650 million, while Japan has about 4,000 neurosurgeons and trainees for a population of 120 million. Korea has 424 neurosurgeons for a population of 41.5 million, and Australasia has 92 neurosurgeons and 19 trainees for 17.5 million people. Various other demographic, institutional, organizational, and economic aspects of neurological health care and delivery, education, and quality control are described. While financing and availability of adequate neurosurgical care remains a major problem in India, it appears that reducing the number of neurosurgical trainees remains, as it is in North America, a major issue in Japan and, to a lesser extent, in Korea. This problem, as well as certification of the quality of training, is being managed effectively in Australasia.

Asia↗
PubMed1988

Stereotactic operation in behaviour disorders. Amygdalotomy and hypothalamotomy.

After a survey of the anatomical and physiological basis of operative treatment of behaviour disorders by stereotactic lesions in the amygdala and the posterior medial hypothalamus the author describes his own experiences with 603 operations for control of conservatively untreatable aggressiveness. In 481 cases bilateral amygdalotomies and in 122 mostly secondary posteromedian hypothalamotomies have been performed. Initially excellent or moderate improvement was achieved in 76%. After a follow-up of more than three years this figure only slightly decreased to 70%. The group of patients who did not positively respond (30%) needs further study to discover the reasons for failure.

Adolescent↗