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Biomedical subjects

M D Cohen

Publications and source records attributed to M D Cohen.

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

Magnetic resonance evaluation of disease of the soft tissues in children.

Magnetic resonance imaging was a sensitive modality for identifying pathology in the soft tissues of 32 children, and it consistently showed more abnormality than CT. Magnetic resonance images are not histology specific, but with careful attention to the location of the abnormality, to the definition of the margins, and to the evaluation of involvement of adjacent muscle, bone, subcutaneous fat, and skin, the correct diagnosis can be strongly predicted in most cases. The ability of magnetic resonance to image in multiple planes aids in the evaluation of the extent of lesions and their relationship to adjacent structures. With magnetic resonance imaging, one can accurately predict the extent of abnormality, and there is great potential for the study of disease of soft tissues.

Child↗
PubMed1986

Clinical utility of magnetic resonance imaging in pediatrics.

A review of over 100 articles and our own experience of scanning nearly 500 children with magnetic resonance (MR) imaging indicate that MR is well tolerated by children. Magnetic resonance is already proving to be the imaging modality of choice for the central nervous system. It should soon prove its utility for the study of most tumors, vascular problems, and infections of the musculoskeletal system. In other regions of the body, MR can identify abnormality well, but many of these abnormalities can be identified well with other modalities, and the precise role of MR is yet to be defined. We anticipate that the number of indications for the use of MR will grow rapidly.

Bone Diseases↗
PubMed1986

Efficacy of magnetic resonance imaging in 139 children with tumors.

One hundred thirty-nine children with neoplasms were studied using magnetic resonance imaging (MRI). This procedure was as accurate as computed tomography in predicting tumor histology, except that MRI was unable to detect small areas of tumor calcification. Magnetic resonance imaging could accurately identify the organ of origin of tumor masses and differentiate soft tissue from fat, fluid, or hemorrhage. In addition, MRI was helpful in planning surgery in many cases: It was better than computed tomography in defining the size and extent of soft-tissue tumor masses. It was accurate in defining the extent of the spread of bone sarcomas in the bone marrow. Without requiring the injection of intravenous contrast agents, it accurately defined displacement, encasement, or invasion of major abdominal blood vessels by Wilms' tumors and neuroblastomas. As a means of evaluating pediatric neoplasms, MRI is noninvasive, painless, and well tolerated by children, and it uses no radiation.

Adolescent↗
PubMed1986

Hepatic imaging in stage IV-S neuroblastoma.

Stage IV-S neuroblastoma describes a group of infants with tumor spread limited to liver, skin, or bone marrow. Such patients, who constitute about 25% of affected infants with neuroblastoma, may expect spontaneous tumor remission. We report 18 infants with Stage IV-S neuroblastoma, 83% of whom had liver involvement. Imaging investigations included Technetium 99m sulfur colloid scan, ultrasound, and CT. Two patterns of liver metastasis were noted: ill-defined nodules or diffuse tumor throughout the liver. Distinction of normal and abnormal liver with diffuse type metastasis could be quite difficult, particularly with liver scans. We conclude that patients with Stage IV-S neuroblastoma have ultrasound or CT examination as an initial workup, with nuclear medicine scans reserved for followup studies.

Adrenal Gland Neoplasms↗
PubMed1986

Effect of ammonium metavanadate on the murine immune response.

Female B6C3F1 mice were exposed to ammonium metavanadate (NH4VO3) by intraperitoneal injection every 3 d at 2.5, 5.0, or 10 mg V/kg for 3, 6, or 9 w and were then assayed for alterations in immunoresponsiveness. Resistance to Escherichia coli endotoxin lethality increased in a dose-dependent manner up to 6 w of exposure, while resistance to viable gram-positive Listeria lethality was depressed in a dose-dependent manner. Comparison of LD20 values indicated a 250-fold decrease in resistance to Listeria at the lowest vanadium exposure and a 40% increase in resistance to endotoxin after the highest vanadium exposure. Peritoneal macrophage phagocytic capacities were decreased in a dose-dependent manner, but viabilities remained unaffected. Rosetting capacity of splenic lymphocytes was increased following vanadium exposure. Liver and splenic enlargement was observed, and examination of splenic tissue indicated enhanced formation of megakaryocytes and red blood cell precursors. Subchronic exposure to vanadium may thus disrupt the normal function of the immune system.

Animals↗
PubMed1986

Hodgkin disease and non-Hodgkin lymphomas in children: utilization of radiological modalities.

If costs of medical care are to be reduced, the choice of which imaging modality to use must be made as carefully as possible. This study was done to show how radiological modalities were used to evaluate patients with Hodgkin disease and non-Hodgkin lymphoma. We kept a record of every radiological study performed on 66 children with both diseases seen in the past 6 1/3 years. The results of these studies were analyzed to see which areas of the body were studied, which imaging modality was used, how frequently the studies were repeated, and how frequently the studies gave abnormal results. Our findings disclosed that radiological studies have been appropriately performed in anatomic regions of the body in which disease is present. New imaging modalities have been introduced, and the use of some of the older modalities has been decreased. With some modalities, such as skeletal survey, liver/spleen scan, whole-lung tomography, contrast studies of the bowel, and excretory urography, utilization is higher than it ought to be in view of the fact that the yield of positive results is low and the information is obtainable in many cases from other more sensitive procedures. These studies should not be performed as a routine on initial evaluation or follow-up of all patients with Hodgkin or non-Hodgkin lymphomas. On initial presentation all patients should undergo chest radiography and CT scanning of both chest and abdomen. A problem area is that the timing of follow-up studies has been somewhat erratic, with some inappropriate studies particularly 3 or 4 years after diagnosis. Too many imaging procedures have probably been done in follow-up of our patients.

Bone Marrow↗
PubMed1986

MRI of Wilms' tumor: promise as the primary imaging method.

The magnetic resonance appearance of Wilms' tumor in 14 patients is described and its clinical utility is evaluated. In all cases, magnetic resonance was correlated with surgical and pathologic findings to assess accuracy. Magnetic resonance accurately identified the primary tumor and its renal origin in all cases, and tumor margins and local extension were accurately demonstrated. Tumor margins were smooth and well defined in nine of 12 cases. Local extension and size were accurately assessed, but because capsular invasion could not be predicted, four surgically proven instances of capsular invasion were missed. Metastatic spread into the liver and inferior vena cava was well documented in four cases and excluded in 10. Magnetic resonance was sensitive for identifying lymph-node enlargement in five of 14 cases, but could not predict the etiology of the enlargement. All Wilms' tumors had signal intensities consistent with prolonged T1 and T2 relaxation times. Signal intensity was highly variable, mainly because of necrosis and hemorrhage within the tumor. Magnetic resonance based on signal intensity could not distinguish Wilms' tumor from other solid renal tumors. Magnetic resonance has the potential for providing the same information as computed tomography, sonography, liver spleen radionuclide scanning, and excretory urography. Although expensive, magnetic resonance will be cost-effective if it can replace all the above techniques. This limited study indicates that magnetic resonance has promise as the primary imaging technique for Wilms' tumors.

Child↗
PubMed1986

Society for Pediatric Radiology John Caffey Award. MR appearance of blood and blood products: an in vitro study.

There are conflicting reports on the appearance of blood and blood clot as seen in the human body by MRI. This study was designed to show the in vitro MR signal intensity of human blood products in the fresh state and to evaluate the serial MRI changes that occur over time (2 weeks). T1 relaxation times were also measured. Anticoagulated whole blood, plasma, serum, white blood cell concentrates, platelet concentrates, lysed red cells, red cell concentrates, and blood clot were studied. The results show that plasma and serum have similar T1 values, as do lysed and intact erythrocytes. T1 of serum and plasma rose initially and then fell with the aging of the samples. T1 of red blood cells, clot, and packed red blood cells decreased for the first 48 hr and then remained constant for 7 days before increasing to the initial values by 2 weeks. Platelets and white blood cells had little influence on the MR image. However, temperature had a significant effect on T1 and signal intensity. In vivo clots are complex mixtures of whole clot, lysing clot, serum, and plasma influenced in various ways by the adjacent normal or diseased tissues. The chemical and physical properties of the mixture change constantly. Because of the clot's complex nature, determining the age of a hematoma from the appearance of clots on the MR image may not be possible.

Adult↗
PubMed1986

Angiomatoid malignant fibrous histiocytoma with extensive lymphadenopathy simulating Castleman's disease.

We report the association in a 10-year-old boy of an angiomatoid malignant fibrous histiocytoma (AMFH) of the left thigh with ipsilateral inguinal, pelvic and extensive retroperitoneal lymphadenopathy, and severe systemic manifestations. These include growth retardation, fever, severe anemia, hypergammaglobinemia, and hypoalbuminemia. At ultrastructural level the tumor was characterized by an abundance of myofibroblasts, occasional histiocytes, and small vessels with marked reduplication of the basal lamina. Biopsies of the inguinal and abdominal lymph nodes showed follicular hyperplasia and massive plasmacytosis indistinguishable from Castleman's disease (giant lymph node hyperplasia) of plasma cell type. The radical surgical excision of the primary tumor in the thigh resulted in the disappearance of the abdominal lymphadenopathy and a marked reduction in size of the pelvic lymph nodes with marked decrease of the gammaglobulins, thus proving that the nodal lesions were the expression of a reactive process to the tumor rather than a coincidental independent lymphoproliferative disorder. Retroperitoneal and pelvic node dissection was performed 1 year after the radical excision of the thigh tumor because of persistent pelvic lymphadenopathy and failure of serum immunoglobulins M and A to return to normal level, with a recent peak of IgA to twofolds that of normal value. Metastatic AMFH was found in the three pelvic nodes. One month postoperatively IgA returned to near normal level whereas IgM remained slightly elevated.

Castleman Disease↗
PubMed1985

Seronegative polyarthritis in giant cell arteritis.

Nineteen of 520 patients with biopsy-proven giant cell arteritis were found to have persistent seronegative, symmetric polyarthritis with a mean joint count of 20 (swollen plus tender). In 9 patients in the onset of polyarthritis occurred prior to the diagnosis of giant cell arteritis, 3 had simultaneous onset, and 7 developed polyarthritis within 3 years after the onset of giant cell arteritis. Ten of the 19 patients demonstrated radiographic features of joint space narrowing and/or erosions. In 1 patient in a synovial biopsy was performed, revealing marked multinucleated giant cell infiltration. A persistent seronegative polyarthritis, although uncommon in giant cell arteritis, may be its presenting symptom. Other symptoms of giant cell arteritis should be sought in patients who exhibit this feature, especially in those whose arthritis begins at age 50 or older.

Aged↗
PubMed1985

Magnetic resonance imaging of lymphomas in children.

Magnetic resonance imaging has been used to evaluate 10 children with lymphomas and was able to identify disease in all 10 cases and monitor response to therapy in all three patients with follow-up studies. It could not distinguish between the different histological types of lymphoma. The image intensity of a diseased spleen in one case was different from that of five other normal spleens in six children with Hodgkins disease. Magnetic resonance imaging compared well with computed tomography and it was especially good at identifying blood vessels.

Adolescent↗
PubMed1985

Mutagenicity of some monoaromatic hydroxamic acids.

The mutagenicity of some monoaromatic hydroxamic acids was tested in the presence and absence of rat liver S-9 with Salmonella typhimurium tester strains TA98 and TA100. Of the five N-(chlorophenyl)-substituted hydroxamic acids and seven N-arylformohydroxamic acids tested, 2 of the first and 4 of the latter series were mutagenic to both strains upon metabolic activation. None of the four N-acetyl-type hydroxamic acids was mutagenic to either strain, even upon activation. Because some of the N-acetyl-derived hydroxamic acids were inactive, whereas the same aromatic nucleus possessing a formyl group displayed significant activity, a consideration of the nature of the aryl group in hydroxamic acid mutagenicity is important.

Animals↗
PubMed1985

Response of osteosarcoma to preoperative intravenous high-dose methotrexate chemotherapy: CT evaluation.

The histologic response of an osteosarcoma to preamputation high-dose methotrexate therapy can be used to determine the optimum maintenance chemotherapy regimen to be administered after amputation. This study evaluates computed tomography (CT) as a method of assessing the response of the tumor to the methotrexate therapy. Nine patients with nonmetastatic osteosarcoma of an extremity had a CT scan of the tumor at initial presentation. This was compared with a second CT scan after four courses of high-dose intravenous methotrexate. Each set of scans was evaluated for changes in bony destruction, soft-tissue mass, pattern of calcification, and extent of tumor involvement of the marrow cavity. These findings were correlated with the histologic response of the tumor as measured by the degree of tumor necrosis. The changes seen on CT correlated well with the degree of the histologic response in seven of the nine patients.

Adolescent↗
PubMed1984

Neonatal intracranial hemorrhage and complicating hydrocephalus.

Real-time ultrasound studies of the head were performed on 96 infants weighing 1500 g or less. This population represented all such infants admitted within the first 72 hours of life to a neonatal intensive care unit over a 9-month period. Intracranial subependymal/intraventricular hemorrhage occurred in 22 (23%) of the infants. Of these 13 (59%) developed ventricular enlargement. Four other infants, in whom hemorrhage was not identified, also developed ventricular enlargement. When it occurred, the ventricular enlargement developed within 2 weeks of the hemorrhage in 77% of cases. It reached its maximum size within 2 weeks in 65% of cases. In 9 of 16 cases the maximal ventricular enlargement was categorized as mild. Spontaneous arrest or resolution of the ventriculomegaly occurred in all but two cases, who required shunting. Clot resolution was slow. It was complete at 3 weeks in only 5 of 18 cases.

Cerebral Hemorrhage↗