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Biomedical subjects

R G Abraham

Publications and source records attributed to R G Abraham.

3 recordsLinked to original sources

A minimally invasive approach to deep-seated brain lesions using balloon dilatation and ultrasound guidance.

Conventional dissection techniques require the excision of a channel from the cortex through the white matter with suction and bipolar cautery for the excision of deep-seated brain lesions. An alternative approach, using a previously described technique, in four cases is illustrated in this article. After craniotomy and dural opening, the index finger portion of a surgical glove was removed, tied over a brain cannula and gently passed towards the lesion under ultrasound guidance. Once the needle-tip was sonologically confirmed to be on the lesion, the balloon was inflated with about 3 to 5 ml of saline. This created a track through which the lesion could be excised under the microscope. The lesions were satisfactorily excised through the track created without removal of brain tissue. The accuracy of this minimally invasive technique can be enhanced when used in conjunction with intraoperative ultrasound guidance.

Astrocytoma↗

The morphological evolution of galaxies.

Many galaxies have taken on their familiar appearance relatively recently. In the distant Universe, galaxy morphology deviates significantly (and systematically) from that of nearby galaxies at redshifts (z) as low as 0.3. This corresponds to a time approximately 3.5 x 10(9) years in the past, which is only approximately 25% of the present age of the Universe. Beyond z = 0.5 (5 x 10(9) years in the past), spiral arms are less well developed and more chaotic, and barred spiral galaxies may become rarer. At z = 1, around 30% of the galaxy population is sufficiently peculiar that classification on Hubble's traditional "tuning fork" system is meaningless. On the other hand, some characteristics of galaxies have not changed much over time. The space density of luminous disk galaxies has not changed significantly since z = 1, indicating that although the general appearance of these galaxies has continuously changed over time, their overall numbers have been conserved.

Journal Article↗

A simplified alloperfused rat heart model for studying myocardial protection.

Isolated hearts are widely used to study myocardial protection because they allow for rigorous control of parameters that is not readily achievable by the in-vivo heart models. The classic Langendorff system and its modifications using asanguinous perfusates have an obvious limitation in that asanguinous reperfusion is clinically irrelevant. The available blood-perfused heart systems are complicated by the use of pumping circuits. In this study, an isolated rat heart, harvested under cold cardioplegia, is alloperfused with the blood coming from an isogenic support rat. The coronary effluent returns to the support rat by gravity. The model was validated by testing its response to normothermic ischemia and reperfusion, and the expected protective effects of hypothermic-cardioplegia are demonstrated. A marked difference in response to ischemia is shown between this model and the buffer-perfused heart. We conclude that alloperfused isolated rat heart model is an inexpensive and more clinically relevant method of screening various new modes of myocardial protection.

Animals↗