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Biomedical subjects

A K Banerjee

Publications and source records attributed to A K Banerjee.

At least 415 records · Page 23Linked to original sources
PubMed1982

Meningioma presenting as recurrent transient cerebral ischemia and intracranial hemorrhage.

Intracranial tumors are sometimes known to appear first as apoplexy. This report describes a patient with a meningioma of the falx who experienced acute onset of symptoms due to intracerebral and subarachnoid hemorrhage and following a history of transient ischemic attacks on exertion. The tumor was an angioblastic-meningioma. The probably source of bleeding and the mechanism of transient ischemic episodes provoked by exertion are discussed.

Adult↗
PubMed1982

Purified matrix protein of vesicular stomatitis virus blocks viral transcription in vitro.

One of the major structural proteins of vesicular stomatitis virus is a small, nonglycosylated, matrix protein which associates with the nucleocapsid core during final stages of morphogenesis and budding. Biochemical and genetic studies suggested that the matrix protein regulates RNA synthesis both in vitro and in vivo. We have purified biologically active matrix protein from the virus and have directly shown that it significantly inhibits RNA synthesis in vitro mediated by the virion-associated RNA polymerase at low ionic strength (0.02 M). The inhibition was greater than 80% when the ratio of matrix protein to the major nucleocapsid protein in the transcribing complex was 2:1 (wt/wt). The inhibition was found to be at the level of RNA chain elongation and not at the initiation step. Electron microscopic studies revealed that inhibition of transcription by matrix protein was accompanied by a profound structural change of the transcribing nucleocapsid from an extended structure to a highly compact form. At higher ionic strength (0.12 M), the matrix protein failed to interact with the nucleocapsid. The matrix protein appears to be involved in condensing the nucleocapsid and blocking transcription during maturation of the virus particle.

Gene Expression Regulation↗
PubMed1982

Radiation retinopathy in diabetes mellitus: report of a case.

A case of radiation retinopathy in a diabetic individual who received a total dose of 45 Gy for lymphoblastic lymphoma of the orbit is reported. The relationship between radiation retinopathy and diabetes mellitus is discussed.

Diabetes Complications↗
PubMed1981

Purified vesicular stomatitis virus contains an enzyme activity that synthesizes cytidylyl (5'-3') guanosine 5'-triphosphate in vitro.

An enzyme activity that synthesizes cytidylyl (5'-3') guanosine 5'-triphosphate (pppGpC) in vitro has been identified in purified vesicular stomatitis virus. The activity is discernible after a lag period which is reduced in length with increasing virus concentration. The lag is eliminated by addition of pppGpC or ppGpC which are effective primers and stimulate dinucleotide synthesis linearly. The requirements of the reaction with respect to MgCl2, NaCl, and temperature are similar to those for viral mRNA synthesis in vitro. The activity, together with the viral L and NS proteins, is removed from virions by treatment with 0.8 M NaCl. The particulate fraction from infected cells that contains the transcribing subviral ribonucleoprotein particles also contains the enzyme activity. The corresponding fraction from uninfected cells does not, indicating that the activity is mediated by virus-specific proteins. Possible functions of the dinucleotide in the life cycle of the virus are discussed.

Animals↗
PubMed1981

Wasted leg syndrome: a clinical, electrophysiological and histopathological study.

Forty cases of 'wasted leg syndrome' were studied clinically and electrophysiologically. Muscle biopsy was examined in nine cases, majority of patients were adults engaged in heavy manual work. The illness was noticed incidently with a strictly unilateral wasting of the whole lower limb (in 65% of cases), of all muscles below the knee (in 22.5% of cases) or of quadriceps muscles only (in 12.5% of cases). The nerve conduction studies and the electromyographic pattern suggested anterior horn cell disorder. Neurogenic atrophy was seen in 7 out of 9 muscle biopsies. A follow up in 12 patients (2-6 years) revealed no progression of the disease. It is suggested that possibly these cases represent an entity, clinically different from other anterior horn cell disorders.

Adult↗
PubMed1981

Replication of vesicular stomatitis virus in murine spleen cells: enrichment of the virus-replicating lymphocytes and analysis of replication restriction.

Vesicular stomatitis virus (Indiana strain) will only grow in T lymphocytes which have been stimulated to undergo cell division. Evidence is presented that a considerable enrichment of the vesicular stomatitis virus-replicating T cells may be accomplished in the mouse spleen by passing the spleen cells over glass wool columns. By using this procedure experiments were performed to study the nature of the block in vesicular stomatitis virus replication in unstimulated (nonpermissive) versus mitogen-stimulated (permissive) splenic T cells. The results show that, as is the case in permissive T-cell lines, stimulated normal T cells allow the synthesis of the 42S virion ribonucleic acid.

Animals↗
PubMed1981

Identification of promoter-proximal oligonucleotides and a unique dinucleotide, pppGpC, from in vitro transcription products of vesicular stomatitis virus.

The oligonucleotides synthesized by purified vesicular stomatitis virus in vitro in the absence of one or more ribonucleoside triphosphate precursors have been studied. The oligonucleotides contained the 5'-terminal sequences of the leader RNA and one or more mRNA's. The promoter-proximal oligonucleotides lacked 5'-terminal cap structure and contained triphosphate A. These results suggest that the RNA polymerase is located at multiple promoter sites on the genome RNA from where it initiates transcription. The capping reaction appears to occur subsequently during RNA chain elongation. We have also demonstrated that a unique dinucleotide, pppGpC, of presently unknown function is synthesized in vitro in large amounts during RNA synthesis or in the presence of GTP and CTP only.

Adenosine Triphosphate↗
PubMed1981

Protein status in long-stay geriatric in-patients.

In a study of 50 long-stay elderly patients, no significant biochemical evidence of protein sub-nutrition was found. Although their protein intake increased to a certain degree on a whole-food supplement, there was no alteration in their biochemical and immunological status during the period of supplementation.

Aged↗
PubMed1980

Unique mode of transcription in vitro by Vesicular stomatitis virus.

In addition to the five mRNA species and 47 nucleotide long leader RNA synthesized by purified virions of vesicular stomatitis virus, at least three discrete low molecular weight RNA species having approximate chain lengths of 28, 42 and 70 nucleotides can be detected in vitro. Each of these RNA species displays a unique and characteristic T1 fingerprint profile and contains (p)ppAA as its 5' terminus. By partial sequence analyses, two of the small RNA products, 42 and 28 bases long, were found to contain 5' terminal sequences identical to those in the N and NS mRNAs, respectively. Ultraviolet inactivation studies demonstrate that each of these RNA species has a target size in agreement with its molecular weight indicating independent initiation. Kinetic studies show that the small RNA species are synthesized within 1 min, while mRNA chain completion occurs later in the sequential order N-NS-M-G. These results indicate that viral mRNA synthesis occurs in vitro by multiple initiations at different promoter sites on the genome RNA, and that the elongation and completion of the individual mRNAs depend on prior transcription of 3' proximal genes. We present a model for viral mRNA synthesis in vitro.

Base Composition↗
PubMed1980

In vitro synthesis of the full-length complement of the negative-strand genome RNA of vesicular stomatitis virus.

Under the normal conditions of in vitro RNA synthesis, the virion-associated RNA polymerase of vesicular stomatitis virus synthesizes five monocristronic mRNAs and a 48-nucleotide-long leader RNA that represents the exact 3'-terminal region of the genome RNA [Colonno, R. J. & Banerjee, A. K. (1978) Cell, 15, 93-101]. When the transcribing core was preincubated with ATP and CTP, reisolated, and then incubated in the presence of the beta, gamma imido analogue of ATP (AdoPP[NH]P) and the three normal ribonucleoside triphosphates, the full-length complementary strand of the genome RNA was synthesized in vitro. The results suggest that specific phosphorylated states of regulatory proteins may control transcription in vitro to generate the full-length plus strands.

Adenosine Triphosphate↗