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Biomedical subjects

T L Johnson

Publications and source records attributed to T L Johnson.

At least 19 recordsLinked to original sources
PubMed1992

Use of an implant for intraosseous infusion as supportive therapy for a Vietnamese pot-bellied pig with urethral obstruction caused by a polyp.

A Vietnamese pot-bellied pig with a urethral polyp was supported by total parenteral nutrition given through an intraosseous implant. Peripheral vascular access was difficult to establish and maintain in this anorectic pig, so a pediatric intraosseous implant was placed in the left tibia. Surgical repair of the urethra was not considered possible, and alternative techniques of a functional bypass were unacceptable to the owners, so euthanasia was elected. Histologic examination of the urethra revealed a polypoid structure believed to be similar to benign congenital polyps described in young boys.

Animals↗
PubMed1992

Effects of combining transforming growth factor beta and 1,25-dihydroxyvitamin D3 on differentiation of a human osteosarcoma (MG-63).

Transforming growth factor beta (TGF beta) and 1,25-dihydroxyvitamin D3 (1,25D3), when added simultaneously to a human osteosarcoma cell line, MG-63, induce alkaline phosphatase activity 40-70-fold over basal levels, 6-7-fold over 1,25D3 treatment alone, and 15-20-fold over TGF beta treatment alone. TGF beta and 1,25D3 synergistically increased alkaline phosphatase specific activity in both matrix vesicles and plasma membrane isolated from the cultures, but the specific activity was greater in and targeted to the matrix vesicle fraction. Inhibitor and cleavage studies proved that the enzymatic activity was liver/bone/kidney alkaline phosphatase. Preincubation of MG-63 cells with TGF beta for 30 min before addition of 1,25D3 was sufficient for maximal induction of enzyme activity. Messenger RNA for liver/bone/kidney alkaline phosphatase was increased 2.1-fold with TGF beta, 1.7-fold with 1,25D3, and 4.8-fold with the combination at 72 h. Human alkaline phosphatase protein as detected by radioimmunoassay was stimulated only 6.3-fold over control levels with the combination. This combination of factors was tested for their effect on production of three other osteoblast cell proteins: collagen type I, osteocalcin, and fibronectin. TGF beta inhibited 1,25D3-induced osteocalcin production, whereas both factors were additive for fibronectin and collagen type I production. TGF beta appears to modulate the differentiation effects of 1,25D3 on this human osteoblast-like cell and thereby retain the cell in a non-fully differentiated state.

Alkaline Phosphatase↗
PubMed1992

Detection of HPV 16/18 DNA in cervical adenocarcinoma using polymerase chain reaction (PCR) methodology.

Twenty-two tissue samples of primary adenocarcinoma (adenoCA) of the uterine cervix were evaluated for the presence of HPV 16/18 DNA using the polymerase chain reaction (PCR). PCR was used to specifically amplify the E6-E7 gene region of HPV 16/18 DNA. The amplification products were analyzed using gel electrophoresis and Southern dot blotting with 32p labeled type-specific oligonucleotide probes. HPV 18 DNA was identified in 13/22 (59%) and HPV 16 DNA was identified in 5/22 (23%) of the tumors. There were no tumors with mixed infections. In three patients, two different specimens were evaluated, and there was concordance of HPV typing. The presence of squamous carcinoma in situ, koilocytosis and younger patient age were associated with an increased incidence of HPV 16/18 DNA detection. HPV 16/18 DNA was not detected in six metastatic adenoCA to cervix (four endometrial, two ovarian). We conclude that HPV 16/18 DNA is present in a significant proportion of primary adenoCA of the cervix, and we have identified some clinicopathologic associations. The detection of HPV DNA may be useful in distinguishing primary from metastatic adenoCA of the cervix.

Adenocarcinoma↗
PubMed1992

Ulcer recurrence following duodenal ulcer healing with omeprazole, ranitidine, or placebo: a double-blind, multicenter, 6-month study. The Omeprazole Duodenal Ulcer Study Group.

The present study determined whether the rate of relapse of duodenal ulcer was reduced after ulcer healing with omeprazole compared with ranitidine or placebo. It was made up of a double-blind, randomized, controlled multiple-center trial set within the United States. Patients were candidates if their duodenal or pyloric channel ulcer successfully healed in one of two large multicenter U.S. trials; one compared omeprazole, 20 mg once daily, before breakfast with ranitidine, 150 mg twice daily, and the other compared the same dose of omeprazole with placebo. Two hundred forty (73.8%) of the 325 patients with complete ulcer healing within 4 weeks of starting therapy who were eligible to enter the follow-up study were enrolled. There was no intervention. Endoscopic assessment of ulcer status was performed at 2, 4, and 6 months and whenever patients had symptoms thought to represent return of an ulcer. The lifetable relapse rates for duodenal ulcer according to initial ulcer therapy with omeprazole, ranitidine, or placebo were 76.7% [95% confidence interval (CI), 64%-89.3%], 59.8% (95% CI, 47.8-71.7%), and 50.4% (95% CI, 15.7%-85.2%), respectively. These rates were not statistically significantly different. Seventeen percent of recurrent ulcers occurred at a site different from that of the original ulcer. It is concluded that despite the more rapid rate of duodenal ulcer healing with omeprazole therapy, the rate of ulcer relapse appears similar and independent of whether ulcer healing was accelerated with omeprazole or ranitidine.

Adult↗
PubMed1991

Tuberculous Addison's disease.

Addison's disease is a possible diagnosis in any patient who presents with weakness, weight loss, hyperpigmentation, hyponatremia, and hypotension. Laboratory findings, including depressed levels of cortisol and aldosterone, help to confirm the diagnosis. Computed tomography may reveal adrenal calcification and abnormal-sized adrenal glands. In most cases, autoimmune destruction of the adrenal cortex is the cause of Addison's disease; however, as in the patient described here, tuberculosis is a possible cause.

Addison Disease↗
PubMed1991

Cytologic and clinicopathologic features of abnormal nipple secretions: 225 cases.

A case review of 225 patients with abnormal breast nipple secretions (NS) was done to determine diagnostically useful clinical and cytologic features. The cytologic specimens and medical records from all patients and 45 concurrent breast biopsies were reviewed. Nipple discharge was attributed to fibrocystic disease (FCD) in 81 cases, physiologic disturbances in 62, papillomas in 18, ductal carcinoma (CA) in 5, miscellaneous benign disorders in 14, and unknown causes in 45. Although cytologic examination of NS was very specific in identifying malignancy, the sensitivity of cytology was low. Carcinoma was diagnosed or suspected cytologically in only three of the five CA cases, with no false-positive cytopathologic interpretations. Malignant NS were usually unilateral, hemorrhagic, mass-associated, and in older patients. Males with nipple discharge had a significantly higher incidence of breast cancer (two of nine; 22%) than women with abnormal NS (3 of 216; 1.5%). Papilloma NS were generally unilateral and hemorrhagic; FCD and physiologic NS were mostly serous or milky. Benign NS were not cytologically distinguishable. We conclude that cytologic examination of NS is a specific but insensitive method to identify underlying malignancy. Additional clinical features, including patient age, laterality and character of NS, and radiographic findings, were found to be diagnostically useful.

Adult↗
PubMed1991

Cytologic features of collagenous spherulosis of the breast.

Collagenous spherulosis is generally classified as a component of benign proliferative breast disease. Previous reports have described the histologic features of collagenous spherulosis, but we are unaware of cytologic descriptions of the condition. In this report, the cytologic features of collagenous spherulosis are described and the differential diagnosis is discussed.

Adult↗
PubMed1991

U.S. experience with omeprazole in duodenal ulcer. Multicenter double-blind comparative study with ranitidine. The Omeprazole DU Comparative Study Group.

To assess the comparative efficacy of omeprazole 20 mg, a proton pump inhibitor, versus ranitidine 150 mg twice a day, an H2-receptor antagonist, in healing duodenal ulcers we performed a randomized, double-blind, multicenter trial in 309 patients with endoscopically diagnosed ulcers. Patients were treated for up to four weeks and were seen at week 2 and at week 4, if unhealed at week 2, for determination of ulcer status by endoscopy, review of daily self-assessment symptom diaries, and clinical laboratory including fasting serum gastrin. Gastrin levels were repeated two weeks after cessation of study medication. Evaluation of baseline demographic and laboratory parameters demonstrated no significant differences between the two groups at entry. At week 2, 42% of the omeprazole and 34% of the ranitidine-treated patients were healed (P = NS). At week 4, there was a 19% advantage in ulcer healing for the omeprazole-treated patients in comparison to those treated with ranitidine (82% vs 63%, respectively, P less than 0.05). Healing of ulcers greater than or equal to 1.0 cm occurred in 83% of those treated with omeprazole versus 37% treated with ranitidine (P less than 0.01). There were no significant differences in rate of pain relief or incidence of clinical laboratory abnormalities. Mean fasting serum gastrin value during treatment increased over the baseline in both groups, (P less than 0.05). The percent change was significantly greater with omeprazole but few patients had elevations above the upper limit of normal for the assay. Both drugs were well tolerated. Omeprazole 20 mg demonstrated superiority in healing duodenal ulcers at four weeks in comparison to ranitidine 150 mg twice daily and was more effective in healing ulcers greater than or equal to 1.0 cm.

Double-Blind Method↗
PubMed1991

Chromosomal assignment in mouse of matrix Gla protein and bone Gla protein genes.

Matrix Gla protein (MGLAP) and bone Gla protein (BGLAP) are calcium-binding, vitamin K-dependent proteins produced by cells of the osteoblastic lineage. Sequence homology suggests that the genes for these proteins evolved from a common ancestor. Somatic whole cell hybrids and karyotypically simple microcell hybrids were used to map Mglap to mouse Chromosome 6 and Bglap to mouse Chromosome 3. Human MGLAP has previously been mapped to chromosome 12p, a region with homology to mouse Chromosome 6, and human BGLAP has been mapped to chromosome 1q, a region with homology to mouse Chromosome 3. It appears that BGLAP is the third calcium-binding protein that maps to human chromosome 1q and mouse Chromosome 3.

1-Carboxyglutamic Acid↗
PubMed1991

HPV detection by polymerase chain reaction (PCR) in verrucous lesions of the upper aerodigestive tract.

Nineteen formalin-fixed, paraffin-embedded verrucous lesions of the upper aerodigestive tract (UADT) were evaluated for the presence of human papillomavirus (HPV) 6b/11, 16, and 18 DNA sequences using the polymerase chain reaction (PCR), in-situ hybridization, and dot blot analysis. HPV DNA was confirmed in two dysplastic papillomas only; both cases contained HPV 6b/11. E6-E7 portions of HPV DNA was not reproducibly detected in any of the 11 verrucous carcinomas, 4 verrucous hyperplasias, or 2 mature papillomas. In-situ hybridization and dot blot analysis confirmed HPV 6b/11 in the two dysplastic papillomas and failed to identify HPV in the other verrucous lesions.

Adult↗
PubMed1991

Lymphangioma circumscriptum of the vulva. A report of two cases.

Lymphangioma circumscriptum is an uncommon dermatologic problem that only rarely affects the vulva. It is considered to be a circumscribed developmental defect of lymphatic tissue in the dermis. We encountered two patients whose clinical manifestations required management with extensive vulvar surgery. These cases illustrate the spectrum of presentation of this disorder and its treatment.

Adult↗
PubMed1991

Skeletal muscle following tonic overload: functional and structural analysis.

Functional overloading of skeletal muscle induces a compensatory hypertrophy as an adaptive response to increased functional demand. Overload of the extensor digitorum longus (EDL) muscle (129 ReJ strain male mouse) was induced by unilateral surgical removal of a synergistic muscle, tibialis anterior (TA). Response of the EDL to overload for 7, 21, and 42 d was analyzed for changes in 1) muscle weight, 2) myofiber type distribution, 3) myofiber cross-sectional area by fiber type, 4) speed of contraction and relaxation of the muscle, 5) force of contraction, and 6) myofiber morphologic integrity. The weight of the EDL significantly increased. The overload caused no impairment of muscle contractility and did not have a significant effect on isometric twitch contraction time to peak tension or the time to one-half relaxation of the twitch. Overloaded muscles demonstrated a transient shift in fiber type profile with preferential hypertrophy of Type IIA fibers that occurred in the early phase of overload while type IIB fibers were recruited by 42 d. No significant increase in myofiber number in overloaded muscles occurred. Some morphologic changes in over-loaded muscles parallel those found in patients with neurogenic muscular disorders. However, overloaded muscle did not exhibit a significant occurrence of fiber branching from controls in the midbelly region of the muscle.

Adaptation, Physiological↗
PubMed1991

Transfer and expression of a Streptomyces cholesterol oxidase gene in Streptococcus thermophilus.

The recombinant plasmid pNCO937 (8.1 kbp) containing a Streptomyces sp. cholesterol oxidase gene was introduced into Streptococcus thermophilus by electrotransformation. Transformation frequency was 7.2 x 10(5) colony forming units/micrograms of DNA. The presence of the cholesterol oxidase gene in S. thermophilus was confirmed with Southern blot analysis using a biotinylated probe. Thin-layer chromatographic analysis showed the expression of the Streptomyces cholesterol oxidase gene resulting in the oxidation of cholesterol to 4-cholesten-3-one. S. thermophilus may be a suitable host for the expression of other genes regulating prokaryotic cholesterol metabolism.

Animals↗
PubMed1990

Cloning and expression of peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase F in Escherichia coli.

The peptide-N4-(N-acetyl-beta-D-glucosaminyl) asparagine amidase F (PNGase F) gene from Flavobacterium meningosepticum was cloned into a high copy number Escherichia coli plasmid. Levels of PNGase F activity produced in cultures of the recombinant strain were up to 100-fold higher than those obtained in cultures of F. meningosepticum. The complete PNGase F gene sequence was determined. Comparison of the predicted amino acid sequence of pre-PNGase F to the N-terminal sequence of the native mature enzyme indicates that the protein is synthesized with a 40-amino acid signal sequence that is removed during secretion in F. meningosepticum. The recombinant PNGase F produced in E. coli is a mixture of products comprised predominantly of two proteins with molecular masses of 36.3 and 36.6 kDa. These proteins have a higher apparent molecular mass than the 34.7-kDa native enzyme. N-terminal amino acid sequencing demonstrated that these higher molecular mass products result from cleavage of the pre-PNGase F in E. coli upstream of the native N terminus. The PNGase F gene was engineered to encode a preenzyme that was processed in E. coli to give an N terminus identical to that of the native enzyme. Purified preparations of this form of recombinant PNGase F were shown to be suitable for glycoprotein analyses since they possess no detectable endo-beta-N-acetylglucosaminidase F, exoglycosidase, or protease activity.

Amidohydrolases↗
PubMed1990

ABC-immunoperoxidase staining of cytologic preparations: improvement of specificity.

Immunoperoxidase (IP) methods perfected on formalin-fixed, paraffin-embedded tissues (FFPE) and then applied to aspirate smears may result in high background staining and a significant number of false-positive results. This is especially true if polyclonal primary antibodies are used or if aspirates and fluids contain a high interstitial or serum protein content. Because of a recurring problem with antiserum to alpha-fetoprotein (AFP), AFP was selected as the primary test antibody with which to evaluate our avidin-biotin complex (ABC)-IP method. The same method, with diaminobenzidine (DAB) or aminoethylcarbazole (AEC) chromogens, was performed on six types of cytologic preparations of a fresh liver specimen. The liver did not stain for AFP in FFPE and frozen tissue; therefore, it could be used to evaluate potential false-positive staining of direct touch imprints, washed aspirate smears, and cytospins that were both air-dried and alcohol-carbowax-fixed. Initial chromogen incubation times were standardized to give identical results on AFP-positive fixed hepatoma and fetal liver controls. Cytologic preparations immunostained with ABC-IP with AEC chromogen resulted in varying background and hepatocyte staining. In comparison, the ABC-IP method using DAB chromogen resulted in no false-positive results and a clean background. The ABC-IP method with AEC standardized for sensitivity on a fixed tissue control required a markedly shortened chromogen incubation time to preclude significant false-positive staining of cytology specimens. It appears that use of AEC chromogen for this antibody with incubation time standardized on a FFPE tissue control and then applied to cytologic preparations also amplifies nonspecific and background staining, contributing difficulty in assessing a true-positive result.(ABSTRACT TRUNCATED AT 250 WORDS)

Avidin↗
PubMed1990

Normal human colon cells suppress malignancy when fused with colon cancer cells.

Normal human colon mucosa cells and cells obtained from histologically normal tissues near that cancer were fused with human colon cancer cells. Resultant hybrid populations of normal and malignant cell fusions behaved as nonmalignant cells in culture, were unable to grow in soft agar, did not express tumor-associated antigens, and were nontumorigenic in nude mice. Autofusion of the cancer cell population led to a phenotype intermediate between normal and malignant cells. That is, the cultures had a much lower plating efficiency in soft agar, and the tumors had a longer latency and slower growth rate in nude mice. This is the first cell culture system to demonstrate that normal epithelial cells can suppress malignancy of their autologous cancer cells, and is a prelude to more extensive studies of genetic events involved in malignant conversion of human colonic epithelium.

Animals↗