Search PubMed⌕ Search

Biomedical subjects

J L Fox

Publications and source records attributed to J L Fox.

At least 217 records · Page 12Linked to original sources
PubMed1986

Bovine galactosyltransferase: identification of a clone by direct immunological screening of a cDNA expression library.

A 1.3-kilobase cDNA clone (7A) coding for bovine galactosyltransferase (glycoprotein 4-beta-galactosyltransferase, EC 2.4.1.38) was isolated from a lambda gt11 expression library by immunological screening with monospecific polyclonal antisera to the affinity-purified bovine enzyme. The nucleotide sequence of this clone predicts an open reading frame that starts at the 5' end of the insert and codes for a polypeptide of 334 amino acids with Mr 37,645. Based on a Mr of 57,000 for the membrane-bound enzyme this clone accounts for approximately 61% of the coding sequence. Portions of the predicted amino acid sequence matched the six tryptic peptides isolated from affinity-purified bovine galactosyltransferase. Clone 7A hybridizes to a 4.8-kilobase bovine mRNA and identifies multiple EcoRI restriction fragments in bovine, murine, and human DNA.

Amino Acid Sequence↗
PubMed1986

Histiocytosis-X of the spinal cord: a case report.

A rare case of histiocytosis-X of the spinal cord with evidence of intramedullary infiltration and epidural spinal cord compression is reported. The clinical, radiological, and histopathological features are discussed, and the pertinent literature is reviewed.

Cauda Equina↗
PubMed1986

Cystic necrosis of the spinal cord in compressive cervical myelopathy: demonstration by iopamidol CT-myelography.

Seven consecutive patients with compressive cervical myelopathy were studied with standard water-soluble contrast myelography and immediate CT followed by delayed CT of the spinal canal at 10 to 12 hr. Every case demonstrated findings suggestive of necrosis and/or cavitation of the central portions of the spinal cord on the delayed CT study. Two types of abnormalities were visualized in the form of delayed collections of contrast media inside the cord: bilateral enhancement, a double-barreled "snake-eyes" appearance at or near the level of compression (consistent with central gray matter necrosis and/or cavitation--local syringomyelia ex-vacuo); and longitudinally oriented, "pencil-shaped" central enhancement of variable length distant from the level of compression (consistent either with an enlarged central canal--hydromyelia ex-vacuo--or with necrosis and/or cavitation extending craniad and caudad from the area of maximal compression and located in or near the anterior portion of the dorsal columns--distant syringomyelia ex-vacuo). These findings, supported by previous reports of autopsy specimens, may explain in part: the frequent discrepancy between the levels of maximal cervical compression and the variable neurologic signs; and the frequent lack of improvement in clinical signs after surgical decompression of the spinal cord at this late stage of the illness. We believe similar intramedullary lesions may be present in other cases of chronic compression of varying etiology at any location within the spinal cord.

Adult↗
PubMed1986

Extensive dural arteriovenous malformation. Case report.

A child with an extensive dural arteriovenous malformation (AVM) of the sigmoid sinus and bilateral occlusion of the transverse sinus is reported. His intracranial venous flow had become rerouted through the right cavernous sinus and then into the right ophthalmic veins. The AVM was associated with severe hydrocephalus and a progressive devastating neurological deficit. The hemodynamic and intracranial pressure changes as well as the mechanism of sinus thrombosis are discussed. The role of aggressive surgical treatment is emphasized.

Adolescent↗
PubMed1986

The Cushing reflex in the absence of intracranial hypertension.

A case is presented in which the left frontoparietal scalp, skull and dura were excised during removal of a massive squamous cell carcinoma. The exposed and relaxed brain was protected only with split-thickness skin grafts for 23 days before successful rotation of a full thickness scalp flap. During the first postoperative day following tumor removal, lumbar cerebrospinal fluid drainage by indwelling catheter was instituted. Transient cardiovascular signs of the classical Cushing reflex and an ipsilateral pupillary dilation rapidly ensued. This phenomenon lends further support to one of the theories regarding the pathogenesis of the Cushing reflex being a pressure gradient (not high intracranial pressure per se) causing axial distortion of the brain stem. In addition, this case is an example of brain herniation in the absence of clinical intracranial hypertension.

Adult↗
PubMed1985

Amino acid sequence similarity between spinach chloroplast and mammalian gluconeogenic fructose-1,6-bisphosphatase.

Chloroplast fructose-1,6-bisphosphatase is an essential enzyme in the photosynthetic pathway of carbon dioxide fixation into sugars and the properties of this enzyme are clearly distinct from cytosolic gluconeogenic fructose-1,6-bisphosphatase. Light-dependent activation via a ferredoxin/thioredoxin system and insensitivity to inhibition by AMP are unique characteristics of the chloroplast enzyme. In the present study, purified spinach chloroplast fructose-1,6-bisphosphatase was reduced, S-carboxymethylated with iodoacetic acid, and cleaved with either cyanogen bromide or trypsin. The resulting peptides were purified by reversed-phase high performance liquid chromatography. Automated Edman degradation of some of the purified peptides showed amino acid sequences highly homologous to residues 72-86, 180-199, and 277-319 of pig kidney fructose-1,6-bisphosphatase. These findings suggest a common evolutionary origin for mammalian gluconeogenic and chloroplast fructose-1,6-bisphosphatase, enzymes catalyzing the same reaction but having different functions and modes of regulation.

Amino Acid Sequence↗
PubMed1985

Structural localization of the sequence alpha 235-242 of the nicotinic acetylcholine receptor.

Two monoclonal antibodies (mAb 254 and 255) were obtained against a synthetic peptide corresponding to the sequence 235-242 of the alpha-subunit of Torpedo acetylcholine receptor. These mAbs could bind to receptor in native membrane vesicles only when these vesicles were permeabilized, suggesting that the sequence alpha 235-242 is exposed on the cytoplasmic surface of the receptor. Further evidence for the cytoplasmic localization of this sequence was partial competition for binding between these mAbs and mAbs previously demonstrated to bind to the cytoplasmic part of the receptor. A model is proposed which accounts for all the experimental data obtained thus far on the transmembrane orientation of the subunit polypeptide chains.

Amino Acid Sequence↗
PubMed1985

Human T-cell leukemia virus type II: primary structure analysis of the major internal protein, p24 and the nucleic acid binding protein, p15.

The 24,000-molecular-weight major internal protein (p24) and the 15,000-molecular-weight nucleic acid binding protein (p15) of human T-cell leukemia virus type II (HTLV-II) were subjected to amino acid composition and amino-terminal amino acid sequence analysis. A comparison of amino acid composition of p24 and p15 of HTLV-II with those of the analogous proteins of HTLV-I revealed that these two proteins share overall similarity. Further, alignment of the amino-terminal amino acid sequence for the first 27 residues of p24 and 34 residues of p15 from HTLV-II showed extensive sequence homology with analogous proteins of HTLV-I. These data suggest that although disease associated with HTLV-I is malignant T-cell leukemia and that associated with HTLV-II is a relatively benign variant of hairy-cell leukemia, HTLV-I and HTLV-II are closely related to each other, at least in their gag-gene-encoded sequences.

Amino Acid Sequence↗
PubMed1985

Direct membrane method for the study of interface-controlled transport of cholesterol in aqueous media.

Studies were designed to demonstrate the use of a silicone rubber membrane diffusion cell in the mechanistic study of cholesterol mass transfer in aqueous media. The method is shown to be simple, precise, and well suited for delineating conditions which facilitate cholesterol transport. Traditional membrane diffusion resistance was determined with cholesterol solubilized in the nonionic surfactant, polyoxyethylene(10)-nonylphenol ether. The use of a charged surfactant additive, either sodium oleate or benzyldimethyltetradecylammonium chloride, reduced cholesterol membrane flux in a manner consistent with a transport barrier residing in the membrane and micelle interfacial regions. Quantitative determination of total transport resistance was good (CV of greater than 95%) for cases more than 99% interface controlled. Interfacial resistance imparted by the charged surfactant additive was essentially abolished by strong electrolyte (sodium chloride). Electrolyte was utilized in either the upstream or the downstream aqueous compartment to enhance cholesterol transport by a mechanism which is consistent with a marked increase in the frequency of micelle collision with the corresponding membrane surface. When the downstream interfacial component of total transport resistance was "short circuited" by electrolyte in sequential transport runs using the same membrane, a "dumping" of cholesterol by the membrane compartment was observed. Limited studies with a second nonionic surfactant, polyoxyethylene(15)-tridecyl ether, suggest that the structure of separate micelle components may also be related to cholesterol mass transfer which occurs via a micelle collision in the interfacial region.

Cholesterol↗
PubMed1985

Influence of 1-dodecylazacycloheptan-2-one (Azone) on the topical therapy of cutaneous herpes simplex virus type 1 infection in hairless mice with 2',3'-di-O-acetyl-9-beta-D-arabinofuranosyladenine and 5'-O-valeryl-9-beta-D-arabinofuranosyladenine.

The predictive value of a recently developed physical model was tested in the topical treatment of cutaneous infections caused by herpes simplex virus type 1 in hairless mice with two ester prodrugs of 9-beta-D-arabinofuranosyladenine (ara-A) (1). The tests were conducted with 2',3'-di-O-acetyl-ara-A (4) and 5'-O-valeryl-ara-A (3) topically applied with and without 15% 1-dodecylazacycloheptan-2-one (2) (Azone), a percutaneous penetration enhancer. In addition to the in vivo studies, in vitro diffusion cell experiments with excised, full-thickness skin from hairless mice were conducted to determine the penetration enhancement effects of 2. As previously observed, 2 was able to induce remarkably large (100- to 1000-fold) flux enhancements in these in vitro experiments. Consistent with predictions based on the physical model studies, formulations of 3 and 4 without 2 had little or no influence on the pathogenesis of the herpes simplex virus type 1 infections; when 2 was present in the formulations, both 3 and 4 had dramatic therapeutic effects consistent with the predictions made with the physical model. Prodrug 4 with 2 was especially efficacious in the prevention of virus-induced lesions and in the survival of all animals. Similar results were obtained with acyclovir plus 2 in this model system.

Acyclovir↗
PubMed1985

Primary cranial and intracranial chondrosarcoma. A survey.

Fifty cases of intracranial and cranial chondrosarcoma were reviewed in the world literature including two of our own. These were analyzed relevant to their histological subgroup, site of origin, age and sex incidence, calcification and vascularity, recurrence, and metastases. The analysis was done in order to clarify points in the diagnosis, management, and prognosis of this rare tumour. The mesenchymal subtype is a more malignant form with a higher tendency for recurrence, metastasis, and increased vascularity.

Adult↗
PubMed1985

Superolateral orbital exposure and reconstruction.

Based upon experience with 10 cases of surgical excision of orbital tumors, we describe a modification of the supraorbital and lateral approaches to the orbit. This technique gives a wide superior and lateral exposure of the orbital contents for microsurgical removal of orbital tumors. It is particularly applicable to large orbital neoplasms, tumors in the orbital apex, growths with intracranial extension, and medial orbital tumors. Two separate bone flaps are removed: a craniotomy (or cranio-orbital) flap that includes the superior and lateral orbital rim and a smaller, more posterior flap that includes the remainder of the roof and lateral wall of the orbit. After excision of a tumor, the orbital walls can be reconstructed in their entirety or the surgeon can leave out the smaller, posterior flap for orbital decompression. After reconstruction there are no significant anatomic, functional, or cosmetic deficits.

Humans↗
PubMed1985

Syrinx of the conus medullaris and filum terminale in association with multiple hemangioblastomas.

A patient with multiple hemangioblastomas and syrinxes of the cerebellum and spinal cord is presented. An additional mass imaged at the L-3 vertebral level was identified by percutaneous syringography as a bilobular syrinx extending from the conus medullaris into the filum terminale. At surgery the syrinx was opened into the caudal cerebrospinal fluid space and the several hemangioblastomas excised. These spinal tumors all appeared to arise in juxtaposition to the posterolateral sulcus and dorsal sensory roots.

Adult↗
PubMed1985

Medulloblastomas: a review of modern management with a report on 75 cases.

The authors summarize the 8-year experience of a tertiary medical center with 75 cases of medulloblastoma in Saudi Arabia. A discussion of the evolution of modern management of this difficult problem ensues. As 5-year survival statistics approach 80% in some institutions, attention is being focused on the long-term effects of modern therapy and the quality of life led by these children.

Adolescent↗
PubMed1985

Percutaneous ventriculocisternal shunt. Technical note.

A modification of the Torkildsen ventriculocisternal shunting procedure, used successfully in a patient with bilateral obstruction of the foramina of Monro, is described. Through bilateral occipital burr holes, a "U-tube" system interconnected the two lateral ventricles. Spinal fluid was then drained with a separate Spetzler catheter passed from one lateral ventricle into the cisterna magna. A posterior percutaneous insertion technique (standard puncture of the cisterna magna) was used to place the catheter into this subarachnoid space.

Adult↗