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Biomedical subjects

G Lee

Publications and source records attributed to G Lee.

At least 19 recordsLinked to original sources
PubMed1995

Efficient gene activation in mammalian cells by using recombinant adenovirus expressing site-specific Cre recombinase.

A recombinant adenovirus (Ad) expressing Cre recombinase derived from bacteriophage P1 was constructed. To assay the Cre activity in mammalian cells, another recombinant Ad bearing an on/off-switching reporter unit, where a LacZ-expression unit can be activated by the Cre-mediated excisional deletion of an interposed stuffer DNA, was also constructed. Co-infection experiments together with the Cre-expressing and the reporter recombinant Ads showed that the Cre-mediated switching of gene expression was detected in nearly 100% of cultured CV1, HeLa and Jurkat cells. These results suggest that the recombinant Ad efficiently expressed functional Cre and offers a basis for establishing a powerful on/off switching strategy of gene expression in cultured mammalian cells and presumably in transgenic animals. The method is also applicable to construction of recombinant Ad bearing a gene the expression of which is deleterious to propagation of recombinant Ad.

Adenoviridae↗
PubMed1995

Bone marrow B lymphocyte development in c-abl-deficient mice.

Mice homozygous for a mutation in the c-abl tyrosine kinase gene have multiple defects including high postnatal mortality, runting, morphological abnormalities, susceptibility to infections, and reductions in lymphocytes and their precursors. FACS analysis of bone marrow from mutant mice demonstrates variable reductions in pro-B and pre-B cells. While the numbers of cells in these populations are profoundly reduced in some mutants (16 and 1.2% of control pro-B and pre-B cells, respectively), normal levels are found in other individuals. In the affected mutants, some reductions are observed in many stages of B cell development. The response of B cell precursors to the cytokine interleukin-7 is variably affected while that of several other cytokines (stem cell factor, interleukin-3, GM-CSF, G-CSF, and erythropoietin) is normal in c-abl mutants. The population defects caused by the c-abl mutation can be recreated in normal mice by the transfer of adult bone marrow but, surprisingly, not fetal liver. These studies demonstrate that c-Abl signaling pathways may play a role in the earliest stages of B cell development in a developmental stage-specific manner. In spite of these variable abnormalities, however, the hemopoietic system of c-abl mutant animals is surprisingly intact.

Animals↗
PubMed1995

The antiinflammatory activity of topically applied novel calcium-channel antagonists.

The antiinflammatory activities of two novel calcium-channel antagonists, AGN 190742 and AGN 190744, were evaluated in murine models of cutaneous inflammation. These 2(5H)-furanone ring compounds block both depolarization-dependent Ca2+ entry and receptor-mediated responses in GH3 cells. Topical application of AGN 190742 or AGN 190744 inhibits neutrophil infiltration and epidermal hyperplasia induced by repeated treatment of mouse skin with phorbol ester. AGN 190744 also is active in an arachidonic acid model of acute inflammation. These data suggest that topical application of calcium-channel antagonists can inhibit cutaneous inflammatory responses and that AGN 190742 and/or AGN 190744 may serve as useful pharmacological probes for examining these responses in vivo.

Administration, Cutaneous↗
PubMed1995

Micrometastases in bone marrow of patients undergoing "curative" surgery for gastrointestinal cancer.

BACKGROUND & AIMS: Immunohistochemical detection of bone marrow micrometastases has been reported as a prognostic marker in colorectal cancer. The aims of this study were to evaluate the potential advantage of flow cytometry as an objective method of identifying and quantifying micrometastatic deposits within bone marrow and to determine the prevalence and quantity of micrometastases in patients undergoing surgery for gastrointestinal cancers. METHODS: Flow cytometry was first validated by a controlled "spike" experiment in which varying numbers of neoplastic epithelial cells were added to bone marrow, and cytometry was performed in a blinded fashion. Three neoplastic cell lines (colonic and esophageal) with varying degrees of expression of cytokeratin-18 were used. Epithelial cells were detected by dual staining with fluorescence-labeled, monoclonal anti-cytokeratin, and propidium iodide. RESULTS: Cytometry reproducibly detected the presence of > or = 10 neoplastic cells per 10(5) marrow cells. Micrometastases were found in 20%-30% of patients undergoing potentially curative resection of colorectal and gastroesophageal adenocarcinomas. There was a trend toward increasing positivity for marrow deposits with advanced Dukes' staging of colorectal cancer. CONCLUSIONS: Flow cytometric assessment of bone marrow is a reliable, objective, and quantitative method of detecting micrometastatic deposits found in a substantial subset of patients undergoing surgery for gastrointestinal adenocarcinomas.

Adenocarcinoma↗
PubMed1995

Clinical evaluations of a new ovarian cancer marker, COX-1.

A monoclonal antibody was generated against an ovarian cancer cell line, OC-3-VGH and was shown to recognize a unique tumor-associated antigen, COX-1 found in ovarian or cervical tumors. COX-1 can be detected in the cultured shed medium of several ovarian/cervical cancer cell lines, and in the sera of ovarian or cervical cancer patients when assayed by a sandwich immunoassay kit employing this monoclonal antibody. Multi-medical centers clinical trials have been conducted since 1989 to evaluate the efficacy of using this immunoassay procedure for the cancer monitoring. In the case of ovarian cancer, COX-1 immunoassay kit has the sensitivity of 68% as compared to 71% for the corresponding CA 125 kit. When both COX-1 and CA 125 kits were combined for the simultaneous monitoring of cancer patients, the sensitivity could be increased to as high as 87%. Further analysis revealed that serum COX-1 levels in cancer patients are correlated with stages of tumor progression. Following the surgical removal of tumors, greater than 50% of the cancer patients showed dramatic and significant decrease of serum levels of COX-1 antigen. The results of these multi-center clinical studies clearly suggested that COX-1 is a suitable marker for the monitoring and diagnosis of ovarian cancer patients, when used alone or in combination with CA 125.

Antigens, Neoplasm↗
PubMed1995

Pseudologia fantastica and gender identity disturbance in a Chinese male.

A Chinese patient with pathological lying (pseudologia fantastica) and gender identity disturbance is described. The stories "save face" and lack a truly self-aggrandising quality. The importance of keeping "face" and maintaining modest behaviour in the Chinese culture is central to the psychopathology.

Adult↗
PubMed1995

Origin of estradiol fatty acid esters in human ovarian follicular fluid.

The estradiol fatty acid esters are the most potent of the naturally occurring steroidal estrogens. These esters are present predominantly in fat, where they are sequestered until they are hydrolyzed by esterases. Thus they act as a preformed reservoir of estradiol. We have previously shown that ovarian follicular fluid from patients undergoing gonadotropin stimulation contains very high amounts of estradiol fatty acid esters (approximately 10(-7) M). The source of these esters is unknown. They can be formed by esterification of estradiol in the follicular fluid by lecithin:cholesterol acyltransferase (LCAT), or in the ovary by an acyl coenzyme A:acyltransferase. In order to determine which of these enzymatic processes is the source of the estradiol esters in the follicular fluid, we incubated [3H]estradiol with follicular fluid and cells isolated from human ovarian follicular fluid and characterized the fatty acid composition of the [3H]estradiol esters biosynthesized in each. In addition, we characterized the endogenous estradiol fatty acid esters in the follicular fluid and compared them to the biosynthetic esters. The fatty acid composition of the endogenous esters was different than those synthesized by the cellular acyl coenzyme A:acyltransferase, and the same as the esters synthesized by LCAT, demonstrating that the esters are produced in situ in the follicular fluid. Although the role of these estradiol esters in the ovary is not known, given their remarkable estrogenic potency it is highly probable that they have an important physiological role.

Chromatography, Thin Layer↗
PubMed1995

Free colon transfer for resurfacing large oral cavity defects.

Ideal reconstruction of the oral cavity includes a durable lining that is thin, supple, and innervated, and that provides a lubricated surface that facilitates deglutition and speech. This paper describes the use of free colon transfer for relining the oral cavity. In three patients, segments of transverse colon, split along the antimesenteric border, were transferred as free flaps on the middle colic vessels for large defects involving the alveolar ridge, buccal mucosa, floor of the mouth, tongue, and pharyngeal walls. All flaps were transferred successfully without adverse vascular events, abdominal complications, or oro-cutaneous fistulas. One flap was re-elevated 2 weeks postoperatively for additional mandibulectomy. Two patients received postoperative radiation therapy and another patient received planned preoperative radiotherapy. The mucosal surface of the colon flattens to provide a thin, smooth, supple oral lining that produces moderate mucus, coapts well to the convoluted surfaces of the defects, and is durable to mastication and denture wear. Mucosal biopsy 2 years postoperatively in the nonradiated flap reveals normal colon mucosa with abundant mucin-producing cells. Free colon transfer is a "functional" reconstruction of the oral lining. The donor tissue is abundant and capable of resurfacing large, convoluted oral cavity surfaces with a thin, supple, mucus-secreting tissue that allows unimpaired tongue mobility, swallowing, speech, and denture wear. Furthermore, the presence of nonirradiated, mucus-secreting cells provides an avenue to further augment mucin production by topical and systemic agents.

Alveoloplasty↗
PubMed1995

Characterization of feline Helicobacter pylori strains and associated gastritis in a colony of domestic cats.

Twenty-four young adult domestic cats from a commercial vendor were found to be infected with Helicobacter pylori. Histopathologic analyses, selected electron microscopy, and urease mapping were performed on mucosal samples collected from the cardias and fundi, bodies, and antra of these cats' stomachs. H. pylori organisms were abundant in all areas of the stomach on the basis of histologic evaluation and urease mapping. H. pylori infection was associated with a moderate to severe lymphofollicular gastritis in 21 of 24 cats (88%). The gastritis was most pronounced in the antral region and consisted mainly of multifocal lymphoplasmacytic follicular infiltrates in the deep mucosa. The severity of gastritis in the antrum corresponded to high numbers of H. pylori there on the basis of the use of the urease assay as an indicator of H. pylori colonization. Ten of 24 cats (42%) also had small to moderate numbers of eosinophils in the gastric mucosa. All 24 cats had gastric lymphoid follicles, with follicles being most prevalent in the antrum. Electron microscopy of gastric tissue revealed numerous H. pylori organisms, some of which were closely adhered to the mucosal epithelium. Human H. pylori gene-specific primers to ureA and ureB amplified products of similar sizes from H. pylori cat isolates. Digestion of the products with restriction enzymes resulted in fragments characteristic of the restriction fragment length polymorphism patterns of H. pylori isolates from humans. In the domestic cat, H. pylori infection is associated with a lymphofollicular gastritis, consisting of lymphocytic and plasmacytic infiltration into the lamina propria, and the organism appears to provide chronic antigenic stimulation resulting in the formation of gastric lymphoid follicles.

Animals↗
PubMed1995

Temporal headaches and associated symptoms relating to the styloid process and its attachments.

The styloid process is a slender spike-like bony process that is attached to the base of the skull that has been of interest to physicians for centuries. From this process is the attachment for five structures--three muscles and two ligaments are attached to it. Any of these soft tissues of the styloid process are prone to be torn due to trauma by way of detachment of the periosteum from the bone. These lesions may occur from auto accidents, falls, sports injuries, to prolonged medical or dental procedures requiring excessive mouth opening. The detachment of Sharpey's fibres results in the release of noxious chemicals such as kinins, histamines, prostaglandins, etc, which can produce a withdrawal reflex, causing muscle tension, ischaemia, spasm and pain. Pain transmission via C fibres may induce a host of autonomic responses as well. We have observed 11 common pains and symptoms that are associated with soft tissue lesions of the styloid process and stylomandibular ligament. They are (1) headaches localised in the anterior temporal fossa, (2) sore throat and difficulty swallowing in the absence of inflammation, (3) pain radiating to the temporomandibular joint and ear, (4) voice alteration, (5) dry, non-productive cough, (6) pain in the masseter muscle, (7) restricted mandibular opening or the "closed lock", (8) development of the "open lock", (9) sinusitis, congested stuffy nose or post nasal drip, (10) tinnitus, and (11) excessive lacrimation and bloodshot eyes. A few drops of local anesthetic into the styloid process and stylomandibular ligament attachment can temporarily relieve the pain and symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Headache↗
PubMed1995

Successful management of female office workers with "repetitive stress injury" or "carpal tunnel syndrome" by a new treatment modality--application of low level laser.

Female office workers with desk jobs who are incapacitated by pain and tingling in the hands and fingers are often diagnosed by physicians as "repetitive stress injury" (RSI) or "carpal tunnel syndrome" (CTS). These patients usually have poor posture with their head and neck stooped forward and shoulders rounded; upon palpation, they have pain and tenderness at the spinous processes C5-T1 and the medial angle of the scapula. In 35 such patients we focused the treatment primarily at the posterior neck area and not the wrists and hands. A low level laser (100 mW) was used and directed at the tips of the spinous processes C5-T1. The laser rapidly alleviated the pain and tingling in the arms, hands and fingers, and diminished tenderness at the involved spinous processes. Thereby, it has become apparent that many patients labelled as having RSI or CTS have predominantly cervical radicular dysfunction resulting in pain to the upper extremities which can be managed by low level laser. Successful long-term management involves treating the soft tissue lesions in the neck combined with correcting the abnormal head, neck and shoulder posture by taping, cervical collars, and clavicle harnesses as well as improved work ergonomics.

Adult↗
PubMed1994

Urinary kallikrein in the rat: stimulation with angiotensin infusion but depression with increasing sodium concentration.

1. The kallikrein response to angiotensin II infusion in the conscious rat was studied to compare it with the response in the dog. 2. Active kallikrein was measured by the aprotinin-suppressible esterase technique in 20 min periods. Angiotensin (5 x 10(-9) to 5 x 10(-2) micrograms min-1) was infused in 10 mM saline in period 10 (group A), or in 90 mM saline in periods 10-12 (group B). 3. In group A, no dose of angiotensin was antinatriuretic. Natriuresis and urinary sodium concentration were dose dependent. 4. Kallikrein excretion was dose dependent with angiotensin (P < 0.0001) and inversely correlated with urinary sodium concentration (P = 0.011). In natriuretic and non-natriuretic rats, kallikrein excretion after angiotensin was inversely correlated with urinary sodium concentration in the preceding period. 5. In group B, natriuresis and urinary sodium concentration were dose dependent. Kallikrein excretion in periods 10-13 was inversely correlated with urinary sodium concentration in the preceding period (P = 0.0001) and inversely correlated with urinary osmolality in periods 9-13. 6. Infusion of angiotensin II at 5 x 10(-6) micrograms min-1 led to antinatriuresis. 7. Formulae were derived which enabled the opposing effects of angiotensin and urinary sodium concentration on kallikrein excretion to be separated. In group A both these effects were statistically significant only in the natriuretic rats (natriuresis > 20 mumols per period). In group B the formulae showed a dose-dependent rise in kallikrein excretion, which was counteracted by the decrease in kallikrein excretion associated with the increasing urinary sodium concentration. 8. With infusions of 0.9% saline, kallikrein excretion in periods 10-13 was inversely correlated with urinary sodium concentration in the preceding period (P = 0.001). 9. The overall effect in the rat differs from that in the dog, where kallikrein increases with angiotensin natriuresis and dilution of the urine occurs.

Angiotensin II↗
PubMed1994

Somatically mutated member of the human V lambda VIII gene family encodes anti-myelin-associated glycoprotein (MAG) activity.

A highly conserved small family of human V lambda genes was identified by DNA homology to a V lambda gene isolated from a patient with demyelinating peripheral neuropathy, and which encodes an autoantibody with anti-MAG activity. Comparison of the genes indicates that the patient V lambda gene was derived from one of the germline genes. Together with published analyses of other anti-MAG IgM antibodies, which also appear to be mutated in comparison to known germline V genes, these results suggest that development of these pathogenic antibodies may reflect an antigen-driven, T cell-dependent process.

Autoantibodies↗
PubMed1994

Orbital venous approach to the cavernous sinus: an analysis of the facial and orbital venous system.

Carotid-cavernous fistulas are abnormal communications between the internal carotid artery and the cavernous sinus produced by a rupture of the wall of the carotid artery or one of its branches into the sinus. Extradural branches of the internal or external carotid arteries may communicate with the cavernous sinus, producing proptosis, progressive glaucoma, and ocular vascular engorgement. Various approaches to obliterate these fistulas have evolved, many of which carry high morbidity or are precluded by anatomical considerations. Analysis of the venous anatomy of the orbit and face, including human cadaver dissections, reveals a new and safe approach to the cavernous sinus, requiring microsurgical isolation and cannulation of the superior ophthalmic vein through an anterior orbital approach. Selective embolization of a carotid-cavernous fistula can be performed successfully through this route. We present pertinent anatomy and technical considerations and the successful clinical application of these principles. Surgeons familiar with craniofacial anatomy and microvascular techniques can apply these principles and play an active role in the treatment of these complex problems.

Aged↗
PubMed1994

Identification of tau protein regions required for process formation in PC12 cells.

Tau is a neuronal microtubule-associated protein that is required for the development and maintenance of neuronal cell polarity. It promotes microtubule assembly in vitro and we have recently reported that a specific tau region, which spans amino acid residues 154-172 of human fetal tau, is not required for growth of existing microtubules, but is required for nucleation of new microtubules. These residues also confer stronger microtubule binding activity in 3T3 cells. The aim of this study was to investigate the functional organization of tau in relation to its role in promoting process formation in a neuronal model system. We transfected undifferentiated PC12 cells with vectors expressing tau fragments and treated the expressing cells with cytochalasin B to allow process extension. We found that deletion of amino acid residues 154-172 greatly reduced the percentage of transfected cells bearing processes compared to that of cells transfected with full-length tau or with an amino-terminally deleted tau fragment containing residues 154-172. These differences do not appear to result from a quantitative difference in protein expression, as shown by immunoblot analysis of transfected cells. We also observed that while the presence of tau fragments increases acetylation of microtubules, the pattern of acetylation in cells transfected with the fragment missing residues 154-172 is less extensive, suggesting that it does not result in the same level of stabilization as the longer tau fragments. Taxol promoted process outgrowth in cells treated with cytochalasin and restored process outgrowth to cells transfected with the tau fragment lacking this activity. Therefore, process formation involves primarily the stabilization and nucleation of microtubules. We conclude that the residues necessary for conferring microtubule nucleation activity of tau in vitro are important for process formation in vivo. It is likely that these residues influence the binding affinity and therefore the stabilization activity of tau.

Amino Acid Sequence↗
PubMed1994

The preparation and planning of artwork for book publication: the artist's viewpoint.

When becoming involved in the production of artwork for book publications the medical artist must interact and work with publishers through whom authors' instructions are conveyed. Procedures and job titles vary from one publisher to the other and misunderstandings can lead to costly mistakes. From a typical publishing situation a common approach to medical artwork preparation for book publication is described that will prepare the medical artist to work in close cooperation with the publishing team.

Book Industry↗