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Biomedical subjects

E Johansen

Publications and source records attributed to E Johansen.

At least 19 recordsLinked to original sources
PubMed1992

The 5' untranslated region from pea seedborne mosaic potyvirus RNA as a translational enhancer in pea and tobacco protoplasts.

We have exploited the transient expression of foreign genes introduced into plant protoplasts to investigate the effect of the pea seedborne mosaic potyvirus (PSbMV) 5' untranslated region (5'UTR) on the level of gene expression in pea and tobacco protoplasts. The plant viral 5'UTRs were found to increase translation significantly in comparison to a plasmid containing no 5'UTR of viral origin. The enhancement effect of the 5'UTRs of PSbMV and tobacco etch potyvirus (TEV) was found to be similar in pea and tobacco protoplasts, indicating a host-independent role of the potyviral 5'UTRs in enhancing gene expression. Translational enhancement of the two potyviral 5'UTRs was similar to that of the 5'UTR of tobacco mosaic virus (TMV). This observation makes it attractive to use potyviral 5'UTRs as general translational enhancers in future genetic transformations of plants.

Base Sequence↗
PubMed1992

Isolation and characterization of IS1165, an insertion sequence of Leuconostoc mesenteroides subsp. cremoris and other lactic acid bacteria.

We have cloned and characterized an insertion sequence from Leuconostoc mesenteroides subsp. cremoris strain DB1165. This element, designated IS1165, is 1553 bp, has imperfect inverted repeat ends, contains an open reading frame of 1236 bp, and is not related to any previously described insertion sequence. The copy number of IS1165 varies from 4 to 13 in L. mesenteroides subsp. cremoris strains allowing genetic fingerprinting of strains based on location and number of bands on hybridization. IS1165 or closely related elements have been detected by hybridization in L. lactis, L. oenos, Pediococcus sp., Lactobacillus helveticus, and Lb. casei but not in Lactococcus.

Amino Acid Sequence↗
PubMed1992

Cushing's syndrome associated with ectopic corticotropin production and small-cell lung cancer.

PURPOSE: This study was undertaken to review the clinical and laboratory features and response to treatment of patients with Cushing's syndrome associated with ectopic corticotropin (adrenocorticotropic hormone; ACTH) production and small-cell lung cancer (SCLC). PATIENTS AND METHODS: We undertook a retrospective chart review of 545 patients with SCLC seen at Toronto General Hospital between 1980 and 1990 and identified 23 patients (4.5%) with Cushing's syndrome and ectopic ACTH production. RESULTS: There were 17 male and six female patients, with a median age of 60 years. The syndrome was diagnosed at the time of initial presentation of SCLC in 13 patients and at relapse in 10 patients. Seven patients had limited disease and 16 had extensive disease at their initial diagnosis of SCLC, but 20 of 23 had extensive disease at the time of diagnosis of Cushing's syndrome. Ten patients had bone marrow involvement. The most frequent physical findings included edema (83%) and proximal myopathy (61%). All patients had elevated plasma and urinary free cortisol levels; 22 had a hypokalemic alkalosis, and 13 had hyperglycemia. Only one patient had a normal ACTH level. The response rate (complete plus partial) to chemotherapy for patients who had the syndrome diagnosed at initial presentation of SCLC was only 46%, and their median survival was only 3.57 months. Only two patients achieved complete normalization of all hormone parameters, and neither experienced hormone relapse at the time of SCLC relapse. Complications of therapy included gastrointestinal (GI) ulceration (six patients), GI bleeding (four), perforation of a duodenal ulcer (one), pneumonia (10), septic shock (three), and fungal infections (five). CONCLUSION: Ectopic ACTH production is associated with a low response to chemotherapy, short survival, and a high rate of complication to therapy.

ACTH Syndrome, Ectopic↗
PubMed1991

Nucleotide sequence of pea seed-borne mosaic potyvirus coat protein gene.

cDNA of pea seed-borne mosaic potyvirus (PSbMV) RNA was synthesized and cloned in E. coli. Four overlapping clones that cover the complete PSbMV genome, except the extreme 5' terminus, were identified by restriction enzyme mapping, hybridization analysis, and partial sequencing. Overlapping cDNA clones covering 1386 nucleotides of the 3' terminus were sequenced. The nucleotide sequence contains one open reading frame (ORF), followed by an untranslated region of 163 nucleotides and a poly(A)-tract. The deduced amino acid sequence was found to include the C-terminus of the predicted RNA-dependent RNA polymerase and the coat protein. A glutamine-alanine dipeptide was identified as a putative 49-kD proteinase cleavage site at the N-terminus of the coat protein.

Amino Acid Sequence↗
PubMed1991

The complete nucleotide sequence of pea seed-borne mosaic virus RNA.

The complete nucleotide sequence of the RNA genome of pea seed-borne mosaic virus (PSbMV) was determined from cloned cDNA and by direct sequencing of viral RNA. The PSbMV genomic sequence was determined to be 9924 nucleotides in length excluding the poly(A) tract. The RNA contained an open reading frame (ORF) of 9618 nucleotides with the potential to encode a polyprotein with a calculated Mr of 364000 (364K). The ORF was flanked by a 5' untranslated leader sequence of 143 nucleotides and a 3' untranslated region of 163 nucleotides. A comparison of the PSbMV polyprotein with the polyproteins of the potyviruses tobacco etch virus (TEV), tobacco vein mottling virus (TVMV), plum pox virus (PPV) and potato virus Y (PVY) showed that PSbMV had a similar genome organization. The polyproteins had a high level of amino acid identity except in the N-terminal region, which varied in both sequence and length. Putative proteolytic cleavage sites were identified in the polyprotein of PSbMV by comparison with those identified for other potyviruses. The cleavage site between the 6K protein and the 49K proteinase is proposed to occur at the C-terminal side of glutamic acid and not at the C-terminal side of glutamine as in other potyviruses. In addition to the five proteolytic cleavage sites for the 49K proteinase identified previously, a sixth putative cleavage site was identified internally in the 49K proteinase of PSbMV, as well as in the 49K proteinases of TEV, TVMV, PPV, PVY and soybean mosaic virus. Cleavage at this site in the 49K proteinases of TEV, TVMV and PPV would result in an N-terminal protein of 22K to 24K, which is similar in size to the size determined for their VPgs.

Amino Acid Sequence↗
PubMed1991

Is there ever a role for salvage operations in limited small-cell lung cancer?

Combined modality treatment with chemotherapy and radiation produces tumor regression in most patients with small-cell lung cancer, but the impact on survival has been small, and less than 20% of patients with limited disease survive 2 years. Survival time is extremely short after failure to respond or relapse after treatment. Local control remains a problem, with one third of patients having recurrence only at the primary site. In an attempt to prolong survival and perhaps achieve cure, we undertook surgical resection in 28 patients with limited small-cell lung cancer who did not have complete remission with standard treatment or who had only local recurrence after treatment. There were 28 patients, 22 male and six female, median age 61 years (range 41 to 76). All patients had been treated with chemotherapy and 13 had received preoperative radiotherapy to the primary site and mediastinum. Eight patients underwent an operation for relapse after complete remission. Five patients had had no response to treatment, three had had a slight response followed by progression during chemotherapy, and 12 had achieved partial response but had greater than 3 cm residual masses. Twelve patients required pneumonectomy, 15 lobectomy, one patient had unresectable disease, and two had bulky residual masses after the operation. Three others had microscopic residual disease. Pathologic examination showed only small-cell lung cancer in 18 patients, mixed small-cell and non-small-cell in four, and only non-small-cell lung cancer in six. There were only four patients with stage I disease, 10 with stage II, and 14 with stage III. The median survival from the date of diagnosis for the entire group is 105 weeks and from the date of operation, 74 weeks. The projected 5-year survival rate is 23%. The two patients with residual masses died with local progression, and distant metastatic disease developed in 17 others. One patient died at 6 years without recurrent disease. Eight patients are alive 2 to 5 years after diagnosis. Seven of these patients required only a lobectomy, four had stage I disease, two had stage II, and two had stage III disease. Five had pure small-cell lung cancer and three had mixed small-cell and non-small-cell tumors. All of the patients with pathologic stage I disease remain alive compared with one of 10 with stage II disease and two of 14 with stage III. In summary, relapse or failure to respond to chemotherapy may be due to non-small-cell lung cancer or a mixed tumor.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

Surgical treatment for limited small-cell lung cancer. The University of Toronto Lung Oncology Group experience.

Since 1977, 119 patients with limited small-cell lung cancer have undergone combined modality therapy including surgery at our institution. Seventy-nine patients (58 male, 21 female; median age 63 years) had surgery first, and 67 of these had adjuvant chemotherapy. Forty (27 male, 13 female; median age 59 years) had chemotherapy first, and 94% had a complete or partial response before the operation. Pretreatment staging revealed 69 stage I, 27 stage II, and 23 stage III tumors. Twenty-six patients required pneumonectomy, 88 lobectomy, and five had no resection. Four patients had gross and six had microscopic residual disease. Postoperative pathologic examination showed small-cell lung cancer only (n = 95), non-small-cell lung cancer (n = 3), mixed (n = 17), and no residual tumor (n = 4). Postoperative staging revealed 35 stage I, 36 stage II, and 48 stage IIIa tumors. The median survival of the entire group is 111 weeks and the projected 5-year survival rate is 39%. No survival difference was seen between patients treated with chemotherapy before the operation and those undergoing an initial operation followed by chemotherapy (p = 0.756). The median survival for patients with pathologic stage I disease has not been reached, and the projected 5-year survival rate is 51%. This is significantly better than for the patients with stage II (median 82 weeks, p = 0.001) or stage III (median 83 weeks, p = 0.001) disease, who have projected 5-year survival rates of 28% and 19%, respectively. Seven of the 12 patients who had no adjuvant chemotherapy remain alive at 6 to 48+ months. Sixty-seven patients have died (11 had no evidence of disease). Only 10 patients had a relapse in the primary site alone, seven at the primary and distant sites, and 39 only in distant sites. In summary, resection improves control at the primary site, and a significant proportion of patients with stage I (N0) disease achieve long-term survival and cure with combined modality therapy including surgery. Stage II and IIIa patients have survival predictions similar to stage IIIa non-small-cell lung carcinoma treated surgically.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1978

Fine structural studies of radiation-resistant human squamous cell carcinomas.

Squamous cell carcinomas of the oral cavity are relatively common lesions, and often can be controlled by radiation therapy. Recently, a series of these tumors has been encountered which did not respond positively to irradiation, necessitating subsequent extensive surgery. This report describes some fine structural changes which were observed in squamous cell carcinomas following exposure to x-irradiation. In addition to the common, keratin-forming differentiated cell, others which were observed were secretory-like, undifferentiated and phagocytic cells. Undifferentiated tumor cells occasionally became incorporated, at least temporarily, as a component of the blood vessel wall, perhaps reflecting metastatic potentiality. It is proposed that irradiation may either increase potential avenues of tumor cell differentiation or inactivate inhibitors thereof.

Aged↗
PubMed1977

On the ABL1.

Explore the source record for details and available documents.

Acid-Base Equilibrium↗
PubMed1976

Reversion of the gal3 mutation of Escherichia coli: partial deletion of the insertion sequence.

The gal3 mutation of E. coli is an insertion of a DNA sequence, 1,100 base pairs in length, into the operator-promoter region of the galactose operon. This mutation reverts spontaneously to gal+ by excision of the insertion to produce stable, inducible revertants, or by tandem duplications of the gal operon to produce unstable, constitutive revertants. The nature of a third class of revertants, which are stable and constitutive, is the subject of the present study. The stable, constitutive class of revertants included approximately 30% of all gal+ revertants obtained from a gal3 (lambda) strain. Although the constitutive reversions could be transduced by lambda, the efficiency was found to be extremely poor and the rare transductants which did appear seemed to originate from abnormal transducing particles. It was concluded that these reversions were not normally packaged by lambda. In order to facilitate the packaging of these reversions, the chlD-pgl region was deleted from the parent gal3 (lambda) strain. Unexpectedly, the gal3 mutation in the majority of these deletions reverted to produce stable, constitutive reversions exclusively. The explanation proposed was that the chlL-pgl deletions had also removed part of the gal operator-promoter. These revertants were not considered to be true representatives of the stable, constitutive class. The specificity of deletion end-points at the insertion was found only in the gal3 (lambda) strain, and not in gal+, gal+(lambda), or gal3 strains. Moreover, the frequency of spontaneous chlD-pgl deletions increased 10- to 15-fold in presence of the gal3 insertions. A lambdagal phage bearing a true stable, constitutive reversion (galc200) was isolated from the revertant strain by subsequent deletion of the chlD-pgl segment (delta31). Electron micrographs of lambdagal+ and lambdac200 delta31(chlD pgl) DNA heteroduplexes were interpreted to indicate that the stable, constitutive reversion had arisen by a deletion of 3/4 of the gal3 insertion sequence. The main conclusions are: (i) the stable, constitutive reversions of gal3 can arise by partial deletions of the insertion sequence, apparently by elimination of the nucleotide sequence which causes polarity; (ii) the chlD-pgl deletions may exhibit preferential termination at the right extremity of the gal3 insertion in presence of prophage lambda; and (iii) the gal3 insertion appears to inhibit the production of lambdagal particles by providing a nucleotide sequence which is recognized and degraded by a specific endonuclease. It is suggested that inhibition of transducing particle formation by gal3 and the preferred termination of deletions at gal3 might represent related phenomena.

Base Sequence↗
PubMed1975

Analysis of human mandibular movement.

The parametric electrical outputs of the six-transducer mandibulograph were used to analyze three-dimensional pathways, displacement profiles, and velocity profiles of selected mandibular areas during jaw movement. This was accomplished by means of digital computer implementation of derived mathematical equations of motion. Five jaw movements were studied: chewing, open-close, right lateral, left lateral and protrusive. The results demonstrate the analytical and diagnostic value of this method and provice new clarification and insight into the nature of mandibular movements. The following observations summarize the principal findings derived from the analysis of jaw movement patterns of a normal patient. The chewing jaw movement exhibited a smoothly coordinated sequence of events. Lateral jaw motion appeared to be prominent during the masticatory phase and throughout the movement cycle. Mastication was abruptly terminated by a vertical desscent of the mandible through the freeway space, until the condyles began their forward movement producing a rotation in the sagittal plane. T occlusal area continued its downward descent along a nearly vertical pathway producing a compressed figure eight pattern in the frontal plane. The open-close jaw movement exhibited minor periods of hesitancy. Jaw movement was initiated with a forward and downward movement of the condyle occurring at the same time as a downward and backward movement of the occlusal area. This motion produced a rotation in the sagittal plane about a moving axis which was not coincident with the intercondylar axis. The general form of the command open-close jaw movement was that of noncoincident curved pathways in the sagittal plane with little lateral displacement. Closing jaw movement occurred with the condyle in a protruded position...

Adult↗