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Biomedical subjects

T A Morrow

Publications and source records attributed to T A Morrow.

10 recordsLinked to original sources
PubMed1999

Pro-B-cell-specific transcription and proapoptotic function of protein kinase Ceta.

Using a subtractive cloning scheme on cDNA prepared from primary pro-B and pre-B cells, we identified several genes whose products regulate apoptosis. We further characterized one of these genes, encoding protein kinase Ceta (PKCeta). PKCeta transcripts were readily detected in pro-B cells but were absent in pre-B cells. Although both a full-length and a truncated form of PKCeta were detectable in bone marrow pro-B cells, transition to the pre-B-cell stage was associated with increased relative levels of truncated PKCeta. We found that PKCeta is proteolyzed in apoptotic lymphocytes, generating a kinase-active fragment identical to the truncated form which is capable of inducing apoptosis when expressed in a pro-B cell line. Caspase-3 can generate an identical PKCeta cleavage product in vitro, and caspase inhibitors prevent the generation of this product during apoptosis in transfected cell lines. Inducible overexpression of either the full-length or truncated form of PKCeta results in cell cycle arrest at the G(1)/S transition. These results suggest that the expression and proteolytic activation of PKCeta play an important role in the regulation of cell division and cell death during early B-cell development.

Animals↗
PubMed1994

Vertical dome division in open rhinoplasty. An update on indications, techniques, and results.

OBJECTIVE: A new modification of vertical dome division (VDD) in rhinoplasty using cartilage overlap and suturing to reestablish the integrity of the alar cartilages is analyzed and compared with the more standard technique of cartilage resection and suturing. DESIGN: Retrospective before-and-after trial. SETTING: Private patients of one of the authors (P.A.A.) undergoing surgery in the Department of Otolaryngology of the University of Toronto (Ontario). PATIENTS: A consecutive sample of 116 patients having undergone open rhinoplasty with VDD between 1981 and 1990 were evaluated. Seventy-five had VDD before 1987, when a cartilage resection and suturing technique was used (P.A.A.); 41 had their surgery after 1987, with the cartilage overlap and suturing technique. All patients were available for follow-up. The mean follow-up time was 15.2 months, with a range of 6 to 63 months. INTERVENTION: Indications for VDD were lobule asymmetry (47%), retrodisplacement (24%), wide domal arch (22%), hanging infratip lobule (6%), and rotation (1%). Prior to 1987, VDD was performed by dividing the alar cartilages, resecting certain portions, and then suturing the cartilages together again to recreate the alar margin. After 1987, VDD was revised by overlapping the portions of cartilage that would have been previously resected and suturing the overlapping portions to recreate the alar margin. MAIN OUTCOME MEASURES: Patient satisfaction; physician evaluation; physical examination; blinded comparison of preoperative and postoperative photographs; need for revision surgery. RESULTS: Overall, six (5.0%) of 116 patients required revision surgery or had photographic and/or physical evidence of nasal tip irregularities. Three (4.0%) of 75 patients from the cartilage excision group and one (2.4%) of 41 patients from the overlap group required revision surgery. The other two patients, one in each group, had minor tip irregularities not requiring surgery. The tip irregularities were due to nasal bossae in four patients and lobule asymmetries in two. There was no alar notching or lower nasal third pinching. Tip irregularities were three times as likely to occur in patients presenting for revision rhinoplasty than in those for primary rhinoplasty. CONCLUSIONS: Vertical dome division is a powerful tool in rhinoplasty, allowing for complex manipulations of alar cartilages to selectively enhance projection, rotation, and domal arch width. It also allows for correction of lobule asymmetries and elongation or hanging of the infratip lobule. The cartilage overlap technique reduces the occurrence of several common postoperative tip abnormalities and lowers the need for revision surgery when compared with cartilage resection VDD. The reported results can only be considered trends, as sample sizes in the series were too small to allow for statistical significance.

Adolescent↗
PubMed1994

The nasal hinge.

It is generally agreed that rhinoplasty is the most challenging procedure performed by the facial plastic surgeon. Mastery of nasal tip maneuvers to alter tip projection, rotation, and lobule refinement is intrinsic to successful rhinoplasty technique. The nasal hinge region comprises the most lateral aspect of the lower lateral cartilage. Its importance is often overlooked. As the foundation of the nasal base, it plays a key role in tip dynamics and can be sculpted to significantly modify projection, rotation, and lobule refinement. One hundred randomly selected rhinoplasty patients were studied with respect to the indications for hinge maneuvers, techniques applied, and resulting affect on tip aesthetics. Clinical results are shown. The applicability of these hinge techniques is compared with other lateral crural techniques. The importance of the hinge region in rhinoplasty dynamics and the necessity of knowledgeably applying surgical maneuvers in this region are discussed.

Adolescent↗
PubMed1994

Soft tissue rhinoplasty.

The majority of rhinoplasty studies emphasize the management of the cartilaginous and bony nasal framework. Often overlooked is the soft tissue envelope. One hundred consecutive rhinoplasty patients were studied with respect to their soft tissue deformities, the surgical techniques applied for correction, and the aesthetic outcome. Results were analyzed utilizing preoperative and postoperative assessment sheets, progress notes, and photographs. The importance of proper diagnosis and management of soft tissue deformities in achieving superior aesthetic results is discussed. As well, clinical examples of illustrative deformities and their corrections are presented.

Adolescent↗
PubMed1992

itk, a T-cell-specific tyrosine kinase gene inducible by interleukin 2.

T lymphocytes are activated by interactions with antigens, lymphokines, and cell adhesion molecules. Tyrosine phosphorylation has been implicated as important in signaling through each of these pathways, but except for p56lck, a member of the Src family that associates with CD4 and CD8, the protein-tyrosine kinases involved have not been defined. We describe here a tyrosine kinase gene that we have designated itk (for IL-2-inducible T-cell kinase). The itk gene specifies a 72-kDa protein-tyrosine kinase that is related to members of the Src family but lacks two features characteristic of Src kinases: an N-terminal myristoylation consensus sequence and a regulatory tyrosine residue near the C terminus. Analysis of mouse tissues and cell lines indicates that itk is specifically expressed in the T-cell lineage, suggesting that the tyrosine kinase encoded by itk functions in a signal transduction pathway unique to T lymphocytes. On addition of IL-2 to responsive T cells, itk RNA increases in parallel with that of IL-2R alpha, implicating itk in T-cell activation.

Base Sequence↗
PubMed1990

Epithelial myoepithelial carcinoma of the parotid gland.

EMEC is a clear-cell tumor of salivary gland origin. Since it was first recognized as a distinct salivary gland malignancy in 1956, sporadic cases have been reported. A case of an EMEC in a parotid gland of a 77-year-old man is described. The clinical and histopathologic features of this unusual neoplasm, as well as a description of the immunohistochemistry and current management of this uncommon entity are presented.

Adenocarcinoma↗
PubMed1989

Fibrous histiocytomas of the soft palate.

Fibrous histiocytomas (FHs) of the oral cavity are exceedingly rare. We report a case of fibrous histiocytoma located in the soft palate of an 11-year-old male. A review of the English literature shows only 4 previously reported cases in this location. This report includes an overview of the clinical and histopathological features of this fibrohistiocytic disorder. A review of the current classification, as well as the diagnosis and management of these neoplasms as they pertain to the head and neck region are discussed.

Child↗
PubMed1989

Endoscopic nasal surgery.

The purpose of functional endoscopic sinus surgery is to re-establish ventilation and mucociliary clearance by endoscopic removal of diseased tissue from key areas of the nasal cavity. Systematic nasal endoscopy and high resolution computed tomography provide diagnostic information that can allow for the recognition of pathology not identifiable by other means.

Endoscopy↗