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Biomedical subjects

J M Rubin

Publications and source records attributed to J M Rubin.

At least 145 records · Page 8Linked to original sources
PubMed1987

Arnold-Chiari II malformation: intraoperative real-time US.

Nineteen cases in which high-resolution, intraoperative, real-time sonography was performed during decompression of an Arnold-Chiari II malformation were reviewed. The variations of the often complicated hindbrain anatomic features, well known from autopsy series, were shown in detail with intraoperative sonography. The extent of herniation of the cerebellar vermis, the medulla, and the fourth ventricle into the cervical spinal canal, as well as fourth ventricular dilatation, arachnoid cysts, and cervical hydromyelia, were also demonstrated sonographically. Real-time imaging was useful in guiding the neurosurgeon in decompression of the hindbrain, especially the fourth ventricle, in an anatomic area often obscured visually by intense fibrovascular adhesions.

Arnold-Chiari Malformation↗
PubMed1987

Visualization of tumor vascularity in a rabbit VX2 carcinoma by Doppler flow mapping.

Using an ultrasonic dynamic flow imager that displays both soft tissues and color-coded flow in the same two-dimensional slice, we were able to display neovascularity in a rabbit VX2 carcinoma. Intravenous infusion of epinephrine altered the flow dynamics in two arteries, one within the tumor and one at the periphery. Further, we were also able to visualize areas of multidirectional flow presumably due to complex arterial patterns and arteriovenous shunts. It is concluded that the color-coded Doppler instrument may overcome some of the methodological problems associated with tumor diagnosis via flow characteristics in the human breast. The literature indicates that the vascular response to the vasoactive drugs or thermal stress may increase differentiation of malignant breast lesions. This experiment suggests that Doppler images and measurements may be made efficiently with color-coded Doppler images, particularly with the addition of more quantitative features to the imager.

Animals↗
PubMed1987

Investigations on the molecular dosimetry of tobacco-specific N-nitrosamines.

Approaches for assessing molecular dosimetry of 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) in humans by measurement of haemoglobin or DNA adducts are discussed. NNK and NNN form haemoglobin adducts in Fischer 344 rats. Acid or base hydrolysis of the globin gives 4-hydroxy-1-(3-pyridyl)-1-butanone, which can be detected in rat blood up to six weeks after injection of NNK; it may be a useful marker for assessing uptake and metabolic activation of NNK and NNN in tobacco consumers. NNK and its major metabolite, 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAI), methylated DNA of rat liver, lung and nasal mucosa to similar extents. NNAI is formed in human tissues from NNK, but immunoassays for O6-methyldeoxyguanosine (O6-medGuo) in exfoliated oral cells from snuff-dippers have been negative. NNK is also expected to form pyridyloxobutyl adducts in DNA; 32P-postlabelling assays for these adducts are being developed and appear to hold promise for detecting NNK- or NNN-DNA adducts in vivo.

Animals↗
PubMed1986

Computed tomography in the diagnosis and follow-up of American Burkitt's lymphoma.

CT scans of Burkitt's lymphoma in 8 American patients are presented. Computed tomography was the major diagnostic imaging modality in 4, and the abdomen was the most commonly involved site in our patients. CT was found to be the method of choice for diagnostic purposes and for assessing the size of abdominal masses. Furthermore, because of the relative effectiveness of modern chemotherapeutic agents in treatment of this type of lymphoma, CT did and can play a unique role in follow-up of these cases during therapy.

Abdominal Neoplasms↗
PubMed1985

The spine and spinal cord during neurosurgical operations: real-time ultrasonography.

Intraoperative ultrasound scanning of the spinal cord and spine was performed during 36 operations in 35 patients. The technique allows neurosurgeons to evaluate an operative procedure during the operation. Effectiveness of shunt placement in syringomyelia can be detected and the completeness of tumor or disk removal can be determined. Precise locations for biopsy of intramedullary lesions can be made. Periodic motion of the spinal cord at the cardiac rate was also detected. This motion was usually due to transmitted pulsations from the anterior spinal artery and appeared to be most pronounced when the artery was compressed between a mass and the spinal cord. This finding refutes the commonly held idea that spinal cord motion implies that the cord is free within the thecal sac.

Heart Rate↗
PubMed1985

Efficacy of intraoperative US for evaluating intracranial masses.

The efficacy of intraoperative neurosurgical ultrasound (US) scanning was determined in studies of 191 lesions (186 patients). US was deemed to have played a useful role in operations on 101 (53%) of these lesions, including 66 (49%) of the 136 brain tumors. The main utility of US imaging was in locating subcortical masses, but it also proved useful in identifying residual tumor after resection; locating cysts within tumors; delineating surrounding vascular structures; and locating subcortical cysts, hematomas, arteriovenous malformations, and inflammatory masses or abscesses. In light of these findings, US study appears to have a place in many intracranial operations.

Brain Diseases↗
PubMed1985

Dynamic intraoperative imaging and instrumentation of brain and spinal cord using ultrasound.

Intraoperative real-time ultrasound imaging in the neurosurgical operating room is most useful in localizing, characterizing, and guiding the instrumentation of lesions of the brain and spinal cord. In the future, more and more operative procedures will be done using intraoperative ultrasound guidance. The ultrasound scanner, as developed for neurosurgery, will become another instrument in the neurosurgeon's armamentarium.

Biopsy↗
PubMed1984

Computed tomography evaluation of local and extraintestinal complications of Crohn's disease.

Complications of Crohn's disease were demonstrated by computed tomography of the abdomen and pelvis in 7 patients. Four patients had developed abscesses, 2 located in the psoas region and 2 involving the retroperitoneum or the liver. Other abnormalities documented on CT included inflammatory masses, fistulae, carcinoma, mesenteric thickening, and extraintestinal complications such as gallstones, renal calculi, and sacroileitis. Computed tomography was found to be useful in the detection and follow-up of abdominal complications of Crohn's disease.

Abscess↗
PubMed1984

Left ventricular wall motion: its dynamic transmural characteristics.

Cardiac wall motion has been studied extensively. It is usually determined by indirect two-dimensional measurements for the true three-dimensional (3D) motion with its specific speed and direction. Errors are also introduced by using internally fixed reference systems and by the inability to identify precise points on the heart wall during the cardiac cycle. Because of these limitations, the endocardial and epicardial wall motion and their relationship are still unclear. This study was designed to assess endocardial and epicardial wall motion by measuring the direction and speed of implanted markers in an externally fixed 3D coordinate system. Fifty-seven pairs of endocardial and epicardial metallic markers were placed at anterior, lateral, posterior, basal, and apical regions of the left ventricles of 14 normal mongrel dogs. Biplane cineradiographs were performed at 50 frames/sec, and the 3D motions of the markers were analyzed using a specially designed computer system. It was found that the speeds, directions, displacements, and phases of the movements of corresponding endocardial and epicardial points were highly correlated. The correlation coefficients were 0.77 to 0.95 for the mean directions, 0.61 to 0.96 for the mean speeds, and 0.59 to 0.96 for the mean displacements at various regions of the heart, and the periodic movements of the endocardium and epicardium were always in phase. The mean epicardial speeds and displacements are fixed proportions (approximately 70%) of the mean endocardial speeds and displacements despite the differences in absolute values between regions in the same dog and the same regions in different dogs. The correlation coefficients for endocardial and epicardial instantaneous speeds, directions, and velocities ranged from 0.68 to 0.83, 0.81 to 0.88, and 0.77 to 0.86, respectively, for different regions of the heart. The correlation coefficients were significant for both the mean values and the instantaneous values. Thus, when only fixed epicardial points are accessible for wall motion measurements in clinical situations, it is possible to infer the endocardial motion from the epicardial motion.

Animals↗
PubMed1984

Ultrasound evaluation of experimental hydrocephalus in dogs.

The use of real time ultrasound to evaluate experimental hydrocephalus in craniectomized dogs is described. Fifteen dogs were longitudinally evaluated by ultrasound after injection of silicone into the suprasellar cistern and injection of kaolin into the cisterna magna, and later killed. Ventricular size was classified as normal, moderately or severely hydrocephalic according to lateral ventricular width. In 93% (14/15) of the animals the classifications as determined by ultrasound and pathological examination agreed. Both lateral ventricular width and biventricular width as measured by ultrasound had a linear correlation with measurements on the pathologic specimens (p less than 0.001).

Animals↗
PubMed1984

Colloid cysts with and without ventriculomegaly: role of intraoperative real-time ultrasound.

Intraoperative real-time ultrasound was used to assist localization and surgical removal of colloid cysts in patients without ventriculomegaly. In the most commonly used surgical approach for removal of colloid cysts, dilated lateral ventricles can expedite the localization of lesions because, once entered surgically, a dilated ventricle offers more space near the foramen of Monro in which to work. Additionally, the enlargement of the foramen of Monro, seen with hydrocephalus, provides greater accessibility to the colloid cyst. In patients with symptoms related to the colloid cyst. In patients with symptoms related to intermittent obstruction of cerebral fluid flow but with normal-sized ventricles, the precise localization of the foramen of Monro and colloid cyst is more difficult and may result in unnecessary exploration/resection of brain. Using intraoperative ultrasound, the colloid cyst and adjacent anatomic structures can be clearly visualized regardless of ventricular size. Intraoperative ultrasonography has a unique role in the operative treatment of patients with colloid cysts and nondilated ventricles.

Adolescent↗
PubMed1984

The central canal of the spinal cord: ultrasonic identification.

An intramedullary linear echo is frequently visible on real-time intraoperative ultrasound images of the spinal cord. An ultrasonographic-anatomic correlative study of the normal spinal cord of a cadaver demonstrated that these intramedullary reflections correspond to the central canal. Twenty-one cases of spinal surgery employing ultrasound in an adjunctive role are reviewed. In cases of intramedullary lesions this echo is absent or disrupted in the scanning plane of the mass, but it is preserved when the process is extramedullary.

Cadaver↗
PubMed1984

Ultrasound-guided periventricular stereotaxis.

Intraoperative ultrasound can aid the biopsy of deep intracranial lesions. It is, perhaps, less clear whether ultrasound could be useful in functional neurosurgery, where the target is not abnormal in echogenicity. As an example, we chose to investigate in a dog model the periventricular gray target, which is frequently the choice for the placement of electrodes to control intractable pain. Autopsies showed the placement of our electrodes with less than 1 mm of error in four of five brains and a 1.5-mm error in the fifth brain. The largest error was seen to occur on the video screen and was due to our failure to tighten the guide properly. The potential advantages of this technique over conventional stereotaxis include the avoidance of: ventricular catheterization, the injection of contrast agent into the ventricles, the necessity for a stereotactic frame, and multiple x-ray exposures. Also, with real time scanning the surgeon has instant visual confirmation of electrode placement and can observe quickly any significant hematoma formation.

Animals↗
PubMed1984

Intraoperative ultrasonic evaluation of spinal cord motion.

The spinal canals of 11 patients with various pathological conditions, both benign and malignant, were examined intraoperatively using real-time ultrasonography. The spinal cords in eight of these patients with lesions causing cord compression were seen to oscillate rhythmically over each mass with a frequency corresponding to the patient's arterial pulsations. The majority of the observed motion was transmitted or extrinsically induced from compression of the anterior spinal artery. In one case, after resection of an anterior cervical neurofibroma, these oscillations diminished markedly. Spinal cord motion, as described, has important implications for neurosurgery, since it contradicts the previously held belief that oscillations of the spinal cord or dura mater imply a "free" or noncompressed spinal cord. Furthermore, spinal cord motion may play a role in the degradation of computerized tomography images of the cord, since these movements are maximized at the areas with the most severe pathology.

Adult↗