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Biomedical subjects

L D Cahan

Publications and source records attributed to L D Cahan.

34 records · Page 2Linked to original sources
PubMed1984

Human monoclonal antibody against ganglioside GD2: use in development of enzyme-linked immunosorbent assay for the monitoring of anti-GD2 in cancer patients.

Ganglioside GD2 is expressed on membranes of human melanoma cells and induces antibody responses in patients with melanoma. In this study a new enzyme-linked immunosorbent assay was developed for detection of human antibody against GD2. A human IgM monoclonal anti-GD2 antibody was used for development of the assay. The antigen, GD2, was prepared from human brain. Four micrograms of GD2 was required to coat a well in a polystyrene microtiter plate. As little as 10 ng of antibody could be detected. The applicability of the assay for detection of serum anti-GD2 antibody was demonstrated with sera from patients immunized with GD2-positive melanoma cell vaccine.

Antibodies, Monoclonal↗
PubMed1983

Sialyloligosaccharide receptors of binding variants of polyoma virus.

Hemagglutination and lytic infection of host cells by polyoma virus has been shown to require specific sialyloligosaccharide structures. The nature of the sialyloligosaccharide sequence recognized by three binding variants of polyoma virus, the large plaque (LP), small plaque (SP), and Py235 variants, was examined. Hemagglutination of native erythrocytes and erythrocytes derivatized with highly specific sialyltransferases to contain cell surface sialyloligosaccharides of defined sequence was compared for the three variants. In addition, soluble glycoprotein inhibitors of known sialyloligosaccharide structure were used to further elucidate the specificities of the three variants. There are important differences in the receptors for these variants. While all three appear to bind the structure NeuAc alpha 2,3Gal beta 1,3GalNAc the LP and Py235 variant bind the disialyl structure NeuAc alpha 2,3Gal beta 1,3(NeuAc alpha 2,6)GalNAc with much lower affinity than does the SP virus. It is suggested that polyoma virus adsorption to cells may depend on the cell surface content of at least three different sialyloligosaccharide sequences and the relative abilities of the virus variant to utilize them as receptor determinants.

Adsorption↗
PubMed1983

Ganglioside GM2 as a human tumor antigen (OFA-I-1).

A monospecific antibody produced in vitro by a B-lymphoblastoid cell line transformed with Epstein-Barr virus has been shown to recognize a membrane antigen (OFA-I-1) on human tumors and fetal brain. This study identifies the chemical nature of OFA-I-1. The glycolipid fraction of antigen-rich spent medium of an OFA-I-1-positive melanoma cell line, M14, was extracted by chloroform/methanol/water, 4:8:3 (vol/vol), and was separated into fractions of neutral glycolipids and gangliosides by DEAE-Sephadex followed by base treatment and Bio-sil A column elution. OFA-I-1 antigens were found exclusively in the ganglioside fraction when assayed with monospecific anti-OFA-I-1 by an immune adherence inhibition test. The results obtained from thin-layer chromatography of the antigenic M14 ganglioside and sequential glycosidase digestion suggested that the antigen was a ganglioside GM2, GalNAc beta 1 leads to 4(NeuAc alpha 2 leads to 3)Gal beta 1 leads to 4Glc leads to Cer. These results were further supported by testing various authentic gangliosides and neutral glycolipids for OFA-I-1 antigenicity. Only GM2 showed positive reactivity.

Adult↗
PubMed1982

Identification of a human neuroectodermal tumor antigen (OFA-I-2) as ganglioside GD2.

Two monospecific human antibodies (anti-OFA-I-1 and anti-OFA-I-2) produced in vitro by lymphoblast cell lines originating from melanoma patients have been shown previously to recognize cell surface antigens (OFA-I-1 and OFA-I-2) on human tumors and fetal brain: OFA-I-1 is expressed on a variety of human tumors, while OFA-I-2 has been detected only on tumors of neuroectodermal origin. Evidence presented in this report suggests that the two antigens expressed by a cultured human melanoma cell line (M14) are chemically distinct and that OFA-I-2 is a cell surface glycolipid, ganglioside GD2: GalNAc beta 1 leads to 4 NeuAc alpha 2 leads to 8NeuAc alpha 2 leads to 3 Gal beta 1 leads to 4Glc-ceramide.

Antibodies, Monoclonal↗
PubMed1982

Considerations in the diagnosis and treatment of syringomyelia and the Chiari malformation.

A series of patients with abnormalities of the craniocervical junction with and without syringomyelia is reviewed. The impact of computerized tomography scanning on current radiological evaluation is discussed. Air myelography may no longer be necessary for accurate diagnosis. While the results of surgery for the Chiari malformation were good, at least one-half of the patients with syringomyelia showed continued progression of symptoms after posterior fossa surgery. More effective surgical therapy requires a better understanding of the pathogenesis of the syrinx.

Adolescent↗
PubMed1981

Intracerebral neurilemmoma.

Two examples of intracerebral neurilemmoma occurred in the absence of von Recklinghausen's disease. The first case was unique because the patient was clinically asymptomatic, and the second case was unusual with a combination of oligodendroglioma and neurilemmoma in the same mass. The latter lesion arising in persons without stigmata of neurofibromatosis has not been described. The nature of nerve sheath neoplasms in both instances has been verified by electron-microscopy. Clinical features of this rare neoplasm differ from those of acoustic or other cranial nerve tumour, particularly in relation to age and sex. Intracerebral neurilemmoma has been found most often in the first two decades of life and more often in males. Seizures and paresis, although non-specific are common signs and symptoms. Probable histogenesis of this neoplasm from perivascular elements in brain has been suggested.

Adult↗
PubMed1980

Bacterial intracranial aneurysms.

The treatment of 13 patients with bacterial intracranial aneurysms is reported. The incidence of bacterial intracranial aneurysms was 4% of all patients admitted with intracranial aneurysms and 3% of all patients admitted with bacterial endocarditis. Each patient had neurological signs or symptoms suggestive of intracranial disease prior to the diagnosis of an aneurysm. Alpha Streptococcus was the most common infecting organism. All patients were treated with specific, high-dose antibiotics, and five patients underwent surgery as well. There were no surgical deaths. Six of eight nonsurgically treated patients died. A review of the literature confirms a high mortality for patients treated with only antibiotics, and a low mortality for elective surgery. The authors conclude that 1) patients with bacterial endocarditis, who develop sudden severe headache, focal neurological signs or symptoms, or seizures, should undergo serial cerebral angiography every 7 to 10 days throughout their hospitalization; 2) if an aneurysm is identified it should be excised whenever possible; and 3) patients with proximal or multiple aneurysms should be considered for surgery.

Adult↗
PubMed1975

Computer graphics--three dimensional reconstruction of thalamic anatomy from serial sections.

This paper describes an interactive program which uses computer graphics techniques to reconstruct a three dimensional representation of thalamic anatomy from two dimensional serial secretion. Figures traced on a Rand tablet, connected to a DEC-340 display, are digitized and scaled. The three dimensional display capabilities of the Adage AGT-30 are used to present the reconstructed structures. Two dimensional cross sections of an arbitrary plane may also be displayed. The program has applications in stereotaxic surgery, teaching neuroanatomy, and may be used to reconstruct other anatomic structures from serial sections.

Computers↗
PubMedDate not supplied

Relief of seizures from a predominantly posterior temporal tumor with anterior temporal lobectomy.

We report the relief of intractable complex partial seizures in a patient with a posteromesial temporal lobe hamartoma after anterior temporal lobectomy, despite minimal tumor removal. We suggest that the key to successful treatment is the mainly medial, or limbic, location of the tumor, which apparently requires anterior limbic structures for full clinical expression of seizures. We conclude that excision anterior to a posterior temporal lesion can result in seizure relief and that a medial tumor location may be important for successful treatment.

Adult↗
PubMedDate not supplied

Failure of encephalo-duro-arterio-synangiosis procedure in moyamoya disease.

Moyamoya disease is an uncommon cerebrovascular disease characterized angiographically by progressive stenosis of the distal internal carotid arteries and proximal anterior and middle cerebral arteries coupled with the development of a fine network of vessels at the base of the brain. In children, the disease causes recurrent hemisphere ischemia. A newly described operative procedure (encephalo-duro-arterio-synangiosis) was recently recommended by Matsushima and Inaba [Child's Brain 11: 155-170, 1984] and was used in a recent patient treated at the UCLA Medical Center. The procedure did not succeed in revascularizing the brain in spite of clinical and angiographic progression of the disease, but a conventional superficial temporal to middle cerebral bypass operation did.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Intraoperative digital subtraction neuroangiography: a diagnostic and therapeutic tool.

We report our experience with intraoperative digital subtraction neuroangiography to demonstrate its application as a diagnostic and therapeutic technique. Intraoperative neuroangiography was performed on 53 occasions in 43 patients using a portable imaging system. Thirty-two procedures were performed for diagnostic purposes after resection of arteriovenous malformations, clipping of aneurysms, or carotid endarterectomy. Unexpected problems were disclosed in seven cases and were surgically remedied immediately in four. In addition, angiography was used as a therapeutic tool in 21 cases to facilitate intraoperative embolization of a vascular lesion or to enable the angioplasty of a vessel inaccessible without direct surgical exposure. We found that by allowing a combined interventional neuroangiographic and neurosurgical approach, intraoperative angiography opened new avenues for treatment of intracranial vascular abnormalities.

Cerebral Angiography↗