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T L Johnson

Publications and source records attributed to T L Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1987

Expression of ras oncogene p21 antigen in normal and proliferative thyroid tissues.

The ras oncogene p21 antigen (p21) has been identified in several epithelial malignancies, including breast, colon, bladder, and prostate. The pattern and intensity of immunoreactivity between normal and neoplastic tissues has been distinctly different. The authors examined thyroid lesions from 73 different cases by immunohistochemistry for the expression of p21 with a monoclonal antibody (RAP-5). Normal thyroid tissues (4) showed the least immunoreactivity, while papillary carcinomas (8), Hurthle cell carcinomas (10), and follicular carcinomas as (3) showed slightly more intense staining than Hurthle cell adenomas (12) or follicular adenomas (9). Anaplastic carcinomas (4) showed much less intense staining than most other carcinomas, while medullary thyroid carcinomas (5) showed only slight immunoreactivity. Inflammatory thyroid lesions associated with goiters, including Hashimoto's thyroiditis (6) and Graves' disease (8), showed moderate to intense expression of p21 as did multinodular goiters (4). Semiquantitative analysis of staining intensity by serial dilution of the primary antibody showed significant differences in staining between normal thyroid and some carcinomas (P less than 0.05), but not between carcinomas and adenomas. These results show that while antibody RAP-5 detects an antigen that is only weakly expressed in normal thyroids, this antigen is more strongly expressed in benign and malignant thyroid tumors, as well as in inflammatory and nonneoplastic proliferative thyroid lesions. It is thus not helpful in identifying differences between neoplastic and non-neoplastic thyroid lesions.

Adenoma↗
PubMed1987

Indirect immunofluorescence technique to detect monoclonal antinuclear antibody.

Monoclonal proteins directed against nuclear antigens are extremely rare. We describe the use of a double antibody immunofluorescence technique to document the existence of a monoclonal antibody with nuclear antigen activity. The patient was an elderly woman with a small monoclonal protein, but no evidence of a lymphoproliferative or autoimmune disorder. A homogeneous antinuclear antibody (ANA) prompted further studies to determine whether the monoclonal protein was related to the ANA activity. A double-antibody immunofluorescence procedure is described by which the ANA positivity was shown to be entirely due to a monoclonal IgMK protein. It consists of using fluorescein anti-kappa and rhodamine anti-lambda applied to a section of mouse kidney treated with the patient's serum. Documentation of antigenic specificity of monoclonal antibodies by double antibody fluorescence provides a straightforward method that can be utilized by routine clinical laboratories.

Aged↗
PubMed1986

Influence of organotins on rat platelet aggregation mechanisms.

The effects of ten organotins on rat platelet aggregation mechanisms were examined. Bis(tri-n-butyltin)oxide was the most potent inhibitor of both ADP- and collagen-induced aggregation, and it was the only organotin that directly induced aggregation. It also increased the latent period for induction of aggregation by collagen. Triphenyltin hydroxide was a weak inhibitor of both ADP- and collagen-induced aggregation. However, in contrast to bis(tri-n-butyltin)oxide, it decreased the latent period for collagen-induced aggregation. A similar effect also was observed with diphenyltin dichloride, phenyltin trichloride, and cyhexatin. Tri-n-butyltin chloride and tetra-n-butyltin demonstrated specificity in their action since aggregation induced by ADP but not collagen was inhibited. Tri-n-propyltin chloride, trimethyltin chloride, and fenbutatin oxide were without discernible effect on rat platelet aggregation.

Adenosine Diphosphate↗
PubMed1986

Prognostic features of vulvar melanoma: a clinicopathologic analysis.

We studied 19 cases of vulvar melanoma to determine significant clinical and histologic prognostic predictors. The average follow-up time was 32 months. Fourteen patients died of melanoma, four patients are alive with no evidence of melanoma, and one patient is alive with residual melanoma. All disease-free survivors had clinical stage I disease and a maximum tumor thickness of 1.3 mm. The average mitotic count in this group was 5.5 per 10 high power fields (HPF) and 50% of the tumors were superficial spreading melanomas. All survivors were treated by radical vulvectomy with bilateral inguinal lymph node dissection. Of the nonsurvivors, four (28.5%) were clinical stage I, five (36%) were clinical stage II, four (28.5%) were clinical stage III, and one (7%) was clinical stage IV. The average tumor thickness for nonsurvivors was 9.5 mm (range 2.6-18 mm) and the average mitotic count was 13.3/10 HPF. Only three (21%) tumors from nonsurvivors were superficial spreading melanomas; the majority were nodular melanomas. The statistically significant prognostic predictors were clinical stage of disease and tumor thickness. Tumor type (i.e., superficial spreading, nodular, or acral lentiginous) correlated with tumor thickness and was indirectly related to prognosis. The mitotic count was also a useful prognostic feature.

Adult↗
PubMed1985

Proteoglycans from bovine nasal and articular cartilages. Fractionation of the link proteins by wheat germ agglutinin affinity chromatography.

Two forms of link protein, 46 and 51 kDa, are present in proteoglycan aggregates from both bovine nasal and bovine articular cartilages. Studies reported here show that the link proteins bind to concanavalin A, Lens culinaris agglutinin, Ricinus communis agglutinin, soybean agglutinin, and wheat germ agglutinin lectins. When the link proteins are eluted from these lectins with appropriate competing sugars, the 46- and the 51-kDa link proteins elute together and no separation is achieved. However, when the link proteins bound to wheat germ agglutinin are eluted with a 0 to 4 M guanidine hydrochloride linear gradient, a good separation of the 46- and 51-kDa link proteins is achieved. Wheat germ agglutinin affinity chromatography has been used on a preparative scale to isolate the 51-kDa link protein from mature bovine articular cartilage to homogeneity, in amounts sufficient to examine its effect on proteoglycan aggregate size and stability in sedimentation velocity studies. Proteoglycan aggregates were reassembled from proteoglycan monomers and hyaluronate in the absence of link protein, in the presence of both 46- and 51-kDa link proteins, and in the presence of the individual 51-kDa link protein. The sizes of the aggregates were compared in terms of sedimentation coefficients (s(0)20). The stability of the aggregates was compared in terms of the per cent aggregate present at pH 7 and 5. At pH 7, the sedimentation coefficients (s(0)20) of link-free aggregates, aggregates formed with both link proteins, and aggregates formed with 51-kDa link protein were 72, 93, and 112 S, respectively. Thus, the 51-kDa link protein has a pronounced effect on aggregate size. The link-free aggregate was grossly unstable, and only 36% aggregate was present at pH 5. The aggregate formed with both link proteins was effectively stabilized against dissociation and 79% aggregate was present at pH 5. The aggregate formed with 51-kDa link protein was not effectively stabilized against dissociation, and only 60% aggregate was present at pH 5. Thus, despite its pronounced effect on aggregate size, the 51-kDa link protein does not effectively stabilize the proteoglycan aggregate against dissociation. These results suggest that the 51-kDa link protein may selectively increase aggregate size, while the 46-kDa link protein may be required to effectively stabilize the proteoglycan aggregate against dissociation.

Animals↗
PubMed1985

Isolation of dermatan sulfate proteoglycans from mature bovine articular cartilages.

Two species of dermatan sulfate proteoglycans, called DS-PGI and DS-PGII, have been isolated from mature bovine articular cartilages. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis at low ionic strength in 0.01 M phosphate the dermatan sulfate proteoglycans appeared as a single polydisperse species whose molecular weight ranged from 80,000 to 140,000. The dermatan sulfate proteoglycans eluted as a single peak on Sepharose CL-4B chromatography in 4 M guanidine hydrochloride and showed no tendency to separate into two components. Following chondroitinase AC and ABC digestion, a core protein was obtained whose molecular weight was 45,000. However, what appeared to be a single dermatan sulfate proteoglycan was consistently separated into two species of distinctly different mobilities by sodium dodecyl sulfate-polyacrylamide gel electrophoresis at high ionic strength in 0.375 M Tris. The molecular weight of the smaller species (DS-PGII) ranged from 87,000 to 120,000. The molecular weight of the larger species (DS-PGI) ranged from 165,000 to 285,000. DS-PGI self-associates in 0.375 M Tris, while DS-PGII does not. This phenomenon was exploited to separate DS-PGI and DS-PGII by preparative electrophoresis on 5 to 20% gradient slab gels. The immunological identities of the individual species, DS-PGI and DS-PGII, were examined by enzyme-linked immunosorbent assay using polyclonal antiserum to cartilage-specific proteoglycan monomer from bovine articular cartilage and polyclonal and monoclonal antibodies to DS-PGII. The polyclonal antiserum to cartilage-specific proteoglycan monomer did not react with DS-PGI or DS-PGII, indicating that DS-PGI and DS-PGII possess different core proteins from cartilage-specific proteoglycan monomer. Polyclonal and monoclonal antibodies raised against the mixture of DS-PGI and DS-PGII reacted strongly with DS-PGII, but weakly or not at all with DS-PGI. These results suggest that DS-PGI and DS-PGII possess different core proteins and may represent two different species of dermatan sulfate proteoglycans.

Animals↗
PubMed1985

Formamidine-mediated inhibition of rat platelet aggregation.

The formamidine pesticide chlordimeform (CDF) was a strong inhibitor of aggregation of rat platelets induced by collagen and arachidonic acid and was a weak inhibitor of that induced by ADP. With the exception of 4-chloro-o-formotoluidide which was an inhibitor of arachidonic acid-induced aggregation only, the CDF metabolites were without discernible effect on aggregation induced by these agents. Amitraz, another formamidine pesticide, inhibited arachidonic acid-induced aggregation but was without effect on that induced by collagen or ADP. Inhibition of collagen- and/or arachidonic acid-induced aggregation by formamidines was concentration-dependent. Although platelets underwent shape change, primary aggregation was markedly inhibited, and secondary aggregation was abolished in some cases. CDF, its two N-desmethyl metabolites, and octopamine, but not amitraz, caused significantly elevated levels of cyclic AMP in platelet rich plasma as compared to controls; however, this effect did not fully account for the action of formamidines on aggregation.

Adenosine Diphosphate↗
PubMed1985

Biogenic amine uptake by nerve cords from the American cockroach and the influence of amidines on amine uptake and release.

Uptake of 5-hydroxytryptamine (5-HT) by isolated whole nerve cords of the American cockroach, Periplaneta americana (L.), involved a dual component system, with one component consisting of rapid active uptake and the other of passive diffusion. Using high performance liquid chromatography with electrochemical detection, it was shown that nerve cords contained 5-HT levels of about 350 ng/g and an equivalent amount of 5-hydroxyindoleacetic acid (5-HIAA), a 5-HT metabolite not previously reported in cockroach nerve cords. Amidines had no discernable effect on uptake of 5-HT or octopamine by nerve cords or on endogenous levels of 5-HT and 5-HIAA in cords.

Amidines↗
PubMed1985

Rapid method of MIC determinations utilizing tetrazolium reduction.

A rapid preliminary method of determining antibiotic susceptibilities of clinically isolated gram-negative fermentative organisms has been evaluated. The method utilizes tetrazolium dye reduction as a colorimetric indicator of bacterial growth. Tetrazolium dye reduction is incorporated into the standard Micro-Media MIC microdilution testing system and shortens the required incubation period from 15 to 18 hours to 4 hours. Parallel MIC determinations were made by the standard MIC method and by the rapid tetrazolium method. The test organisms included 218 gram-negative fermentative clinical isolates. The overall correlation between the standard and the rapid MIC methods was 93%. Of the 7% discordant results, 6.3% represented minor discrepancies and 0.7% represented major discrepancies. There were no very major discrepancies. The study concluded that the rapid tetrazolium MIC method is an accurate, low-cost, easily implemented method of preliminary antibiotic susceptibility testing for gram-negative fermentative organisms.

Anti-Bacterial Agents↗
PubMed1985

Detection of HLA-DR antigens in paraffin-embedded thyroid epithelial cells with a monoclonal antibody.

The human Class II major histocompatibility (MHC) antigens, or Ia antigens, which are thought to regulate immune cell interaction, can be detected in paraffin-embedded tissues by immunoperoxidase staining with a recently developed monoclonal antibody (LK8D3). HLA-DR antigens were observed in lymphoid tissues, Langerhans cells of the skin, some epithelial cells, and pulmonary alveolar macrophages. The expression of HLA-DR antigens was analyzed in formalin-paraffin sections by immunoperoxidase in 86 normal and abnormal thyroid epithelial tissues. All patients with Hashimoto's disease (8/8) and most patients with Graves' disease (6/8) expressed HLA/DR antigens in the thyroid epithelial cells and in adjacent inflammatory cells. Most papillary carcinomas (12/18), including 3 of 5 follicular variant of papillary thyroid carcinomas, had HLA-DR antigens detected in epithelial cells; whereas medullary thyroid carcinomas (0/5), follicular carcinomas (0/5), and multinodular goiters (0/4) did not have detectable HLA-DR immunoreactivity. A few other thyroid lesions had HLA-DR antigens detected in epithelial cells, including anaplastic carcinomas (2/5), Hurthle-cell tumors (1/16), and thyroid lymphomas (2/2). Monoclonal antibody LK8D3 and two other commercially available monoclonal antibodies against HLA-DR-stained tissues equally well in cryostat sections, but only antibody LK8D3 was effective in formalin-fixed paraffin-embedded tissue sections. These results indicate that epithelial cells from thyroids of patients with autoimmune diseases commonly express HLA-DR antigens. The presence of HLA-DR antigens in most papillary thyroid carcinomas may be helpful diagnostically in cases of follicular variants of papillary carcinomas. The role of HLA-DR expression in autoimmune thyroid disease and in papillary thyroid carcinoma remains to be determined.

Antibodies, Monoclonal↗
PubMed1985

Cardiac paragangliomas. A clinicopathologic and immunohistochemical study of four cases.

Cardiac paragangliomas are extremely rare neoplasms. Four surgically resected tumors were examined by immunohistochemistry and electron microscopy. The patients ranged in age from 18 to 36 years. All patients had hypertension and elevated urine catecholamine levels. Three tumors were located on the posterior left atrium, and one tumor was located in the interventricular groove at the aortic root. The tumors ranged in size from 5 to 7 cm, and they displayed a prominent Zellballen pattern without significant necrosis or mitosis. The tumors were mostly unencapsulated and infiltrated adjacent cardiac tissue in two cases. Immunoperoxidase staining showed that all tumors were positive for chromogranin and neuron-specific enolase. Three tumors were positive for methionine enkephalin. Positive staining for S-100 protein was seen in the sustentacular cells of all tumors but was negative in chromaffin cells. All tumors were negative for insulin, glucagon, gastrin, vasoactive intestinal polypeptide, somatostatin, adrenocorticotropic hormone, calcitonin, serotonin, pancreatic polypeptide, and rat atrial peptide. Ultrastructural studies of all four tumors showed moderate numbers of predominantly norepinephrine-type granules and a few epinephrine-type granules. These results show that cardiac paragangliomas are commonly found in close proximity to the left atrium and have immunohistochemical and ultrastructural features similar to other paragangliomas.

Adolescent↗
PubMed1984

Effect of formamidines on 5-hydroxytryptamine uptake and biogenic amine levels in rat platelets.

Uptake of radioactive 5-hydroxytryptamine (5-HT) by platelets from rats treated intraperitoneally with the insecticide/acaricide chlordimeform (CDF) at 25 mg/kg was not significantly influenced at 1 h; however, uptake of this amine by platelets from rats treated with its N- monodemethyl metabolite (DMC) at the same dosage was significantly inhibited (37%). Two reversed phase high performance liquid chromatographic systems with electrochemical detection were developed with a capacity to separate 11 biogenic amines and related compounds. Only 5-HT, norepinephrine (NE), dopamine (DA), and 3,4-dihydroxyphenylacetic acid (DOPAC) were consistently detected in platelets and plasma samples. At 1 h and/or 24 h postinjection, CDF effected significant decreases in platelet levels of 5-HT, NE, and DA and plasma levels of 5-HT, whereas platelet and plasma levels of DOPAC were significantly increased. DMC effected significant decreases in both platelet and plasma levels of 5-HT. These in vivo studies confirmed previous in vitro experiments which demonstrated that formamidines inhibited uptake of 5-HT by platelets and released endogenous stores of amines from platelets.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Vaccinia virus induces ribonucleotide reductase in primate cells.

Infection of monkey kidney (BSC-40) cells with vaccinia virus strain WR resulted in a marked increase in ribonucleoside diphosphate reductase (EC 1.17.4.1) activity as measured by CDP reduction in cell-free extracts. After a synchronous infection, increased activity was detected at 2 h, peaked at 4 to 5 h, and then declined between 6 and 8 h to the endogenous cellular level. The induction, detectable at 0.5 PFU/cell, correlated strongly with multiplicity of infection to 10 PFU/cell and continued to increase to 50 PFU/cell. It paralleled the previously described induction of viral DNA polymerase and thymidine kinase, suggesting that the reductase may also be a product of early transcription of the viral genome. The inhibition of DNA synthesis throughout infection resulted in prolonged accumulation of reductase activity and delayed and incomplete down-regulation at 8 h, suggesting that repression involves late functions. Rescue of fluorodeoxyuridine-inhibited DNA synthesis with exogenous thymidine restored the normal pattern. Preferential association of the induced reductase with the cytoplasmic sites of vaccinia virus DNA replication (virosomes) was not detected. The induced enzyme is similar in several respects to other eucaryotic ribonucleotide reductases, but is distinct from host cell reductase in response to certain modulators of reductase activity (M. B. Slabaugh and Christopher K. Mathews, J. Virol. 52:501-506, 1984). Full activity required an activator, exogenous reducing equivalents, and iron. Hydroxyurea, EDTA, dATP, and dTTP inhibited CDP reduction, setting this reductase apart from T4 reductase, which is not inhibited by dATP, and from herpesvirus reductase, which requires no activation and is insensitive to deoxyribonucleoside triphosphate inhibition.

Animals↗
PubMed1983

Effects of organotins on rat platelets.

Incubation of rat platelets with organotins inhibited their capacity to take up 5-hydroxytryptamine-14C (5-HT-14C) and stimulated the release of preloaded 5-HT-14C as well as endogenous 5-HT. Similar but less pronounced effects also were observed when platelets from rats treated intraperitoneally with organotins were examined. The relationships of organotin structure to 5-HT uptake inhibition and 5-HT release were similar, with the most active compounds being the trisubstituted derivatives bis(tri-n-butyltin) oxide, tri-n-butyltin chloride, tricyclohexyltin hydroxide, tri-n-propyltin chloride, and triphenyltin hydroxide. Scanning electron micrographs revealed increased platelet aggregation and shape change in organotin treated samples as compared to vehicle treated controls. It was suggested that the action of organotins on rat platelets was due, at least in part, to their known ability to interfere with ATPase mediated systems.

Animals↗
PubMed1983

Influence of formamidines on biogenic amine levels in rat brain and plasma.

Biogenic amine levels in samples of whole brain and plasma following treatment of rats with chlordimeform (CDF), its two N-demethyl metabolites (DMC and DDC), p-chloroamphetamine (PCA), and harmaline were separated by high performance liquid chromatography equipped with fluorescence or electrochemical detection systems. At 1 hr following s.c. injection, CDF (200 mg/kg) caused a reduction in levels of norepinephrine (NE), 5-hydroxytryptamine (5-HT), and tyramine (TRM), an increase in dopamine (DA), and no change in levels of beta-phenethylamine (PEA) in samples of whole rat brain, whereas DMC (100 mg/kg) and DDC (25 mg/kg) effected reductions of brain levels of NE, 5-HT, TRM, and PEA with no change in DA. The effect of DMC (100 mg/kg) on NE and DA levels in brain was followed periodically for 24 hr. Following a significant decrease at 1 hr, NE levels increased to a maximum at 12 hr and remained higher than controls throughout the remainder of the 24 hr test period. DA levels increased during the initial 12 hr and remained significantly higher than controls for the remaining 12 hr. The influence of s.c. vs i.p. administration of DMC (100 mg/kg) on brain amine levels was examined. Intraperitoneal treatment generally resulted in lower amine levels in DMC and vehicle treated animals. Differences in treatment effects were similar for all amines except for 5-HT in which s.c. injection produced a slight reduction, while i.p. injection resulted in a two-fold increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗