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Biomedical subjects

K Johnson

Publications and source records attributed to K Johnson.

At least 433 records · Page 24Linked to original sources
PubMed1987

Effects of anorectic agents in rats bearing the Walker-256 tumor.

Since changes of levels of biogenic amines have been found in some brain areas of rats bearing the Walker-256 tumor, a study was performed to assess the actions of three anorectic agents in such animals. The results obtained by dosage of d-amphetamine, fenfluramine or mazindol, on days 5 and 8 after tumor implantation, failed to demonstrate conclusively any predominant modification of a dopaminergic, noradrenergic, or serotonergic system in the anorectic effects of these agents.

Animals↗
PubMed1986

Nucleotide sequence and transcriptional initiation site of two Pseudomonas aeruginosa pilin genes.

The complete nucleotide sequences of the 1.2-kilobase HindIII fragments which contain the pilin genes of two independently isolated strains of Pseudomonas aeruginosa (PAK and PA103) have been determined and compared to that of strain PA01 (Sastry, P. A., Finlay, B. B., Pasloske, B. L., Paranchych, W., Pearlstone, J. R., and Smollier, L. B. (1985) J. Bacteriol. 164, 571-577). The fragments share extensive regions of homology, including the 5'- and 3'-flanking sequences as well as the 5' end of the pilin gene. The most highly diverged segments of the pilin genes are those which encode the variable carboxyl-terminal region of the pilin polypeptides. The pilin polypeptides each contain a 6-amino acid amino-terminal leader peptide (Met-Lys-Ala-Gln-Lys-Gly) and are nearly identical in the following 60 amino acids. The carboxyl-terminal portion of the pilin polypeptides contain extensive regions of divergence in their amino acid sequences, although hydropathicity analysis of the pilin polypeptides indicated that they are structurally similar. The transcriptional initiation site of the PAK pilin gene has been determined by S1 nuclease mapping. The promoter region at -10 and -35 base pairs from the transcriptional initiation site shows no significant homology to the consensus Escherichia coli promoter, but the -12 and -24 regions show a high degree of homology to promoters which require the ntrA gene product for transcription. Several other Pseudomonas promoters and the promoters of the homologous pilin genes from other bacterial species also share homology to this sequence.

Amino Acid Sequence↗
PubMed1986

Prognostic factors in adenocarcinoma of the uterine cervix.

A group of 136 female patients with adenocarcinoma of the uterine cervix, treated at Memorial Sloan-Kettering Cancer Center between 1949 and 1981, with slides available for review, formed the basis for this study. They ranged in age from 10 to 91 years. Most (73%) had abnormal bleeding, either alone or in combination with other symptoms; 15% were asymptomatic. Eighty percent had a visible abnormality, most commonly an exophytic mass. Clinical stages were: 0 (3%), IB (61%), IIA (14%), IIB (10%), III (4%). There were four major histologic subtypes: mucinous (47%), endometrioid (24%), adenosquamous (15%), and clear cell (9%) carcinoma. Of the many clinicopathologic variables evaluated for prognosis, the most significant was stage of disease (P less than 0.0001). Those with Stage IB disease had a survival probability of 76% at 5 years compared with 49% for those with Stage IIA and 34% with Stage IIB. The endometrioid pattern was associated with a more favorable prognosis than any other histologic subtype (P = 0.02). The presence of lymphatic tumor emboli and/or metastatic carcinoma in any lymph node group was associated with a less favorable prognosis for patients with Stage IB and IIA disease (P less than 0.0001).

Adenocarcinoma↗
PubMed1986

Clinical and immunologic observations in patients who stop venom immunotherapy.

It is currently recommended that venom immunotherapy (VIT) be continued as long as the sensitivity persists (indicated by positive venom skin tests or RAST). In this pilot study, we performed a retrospective survey of the clinical and immunologic effects of stopping VIT. The 82 patients studied had received maintenance VIT for a mean of 14 months and had stopped VIT a mean of 43 months before evaluation. Subsequent "field" stings in 28 patients caused systemic reactions in six cases (22%), which is significantly higher than the 1% to 3% systemic reaction rate in patients who remain on maintenance VIT. The 22% reaction rate is a minimal estimate caused by loss of venom sensitivity in some patients and residual venom-specific IgG antibody levels in others. Reevaluation of venom skin tests and IgG levels was possible in 43 patients. A tenfold decline from before VIT skin test results was observed in 27 patients (63%). Skin tests remained clearly positive in 32/43 (74%), became weakly positive in 9/43 (21%), and 2/43 (5%) became negative. The IgG level declined from typical maintenance levels before stopping VIT (mean 7.2 +/- 1.2 micrograms/ml) to levels typical of untreated patients at the time of retesting (mean 1.95 +/- 0.3 micrograms/ml). Despite the marked fall of IgG antibody, one third of the patients still had levels in the average range observed in patients receiving maintenance VIT. We conclude that there is a substantial risk of anaphylactic sting reaction if VIT is stopped while venom sensitivity persists.

Adult↗
PubMed1986

Cathepsin B: association with plasma membrane in metastatic tumors.

The subcellular localization of cathepsin B activity (EC 3.4.22.1) in three murine melanomas of increasing metastatic potential (Cloudman less than B16-F1 less than B16 amelanotic) was determined. Cathepsin B activity was localized in the heavy mitochondrial fraction of normal murine liver but in the light mitochondrial fraction of the metastatic melanomas; the localization of three other lysosomal hydrolases did not shift. Further purification of the light mitochondrial fraction into L-1 (density = 1.045 g/ml) and L-2 (density = 1.07 g/ml) fractions was achieved on a 30% iso-osmotic Percoll gradient. The L-1 fraction of liver and melanomas contained Na+, K+-ATPase activity; the L-2 fraction of liver contained four lysosomal hydrolase (cathepsins B and H, N-acetyl-beta-glucosaminidase, and beta-glucuronidase) and glucose-6-phosphatase activities. Ultrastructural examination revealed that the L-1 fraction consisted of membrane vesicles and the L-2 fraction of secondary lysosomes. In the B16 melanomas cathepsin B and N-acetyl-beta-glucosaminidase activities were found in both L-1 and L-2 fractions. Specific activities of the two enzymes in the plasma membrane (L-1) fractions increased in correspondence with metastatic potential. Cathepsin H and beta-glucuronidase activities were not localized in the plasma membrane fractions of the B16 melanomas. Localization of hydrolytic enzymes in the plasma membrane of metastatic tumor cells could result in focal dissolution of the extracellular matrix and thereby invasion and metastasis.

Acetylglucosaminidase↗
PubMed1986

IgM nephropathy associated with penicillamine.

In this report we describe the development of idiopathic nephrotic syndrome with an IgM nephropathy in a 53-year-old patient undergoing treatment for active rheumatoid arthritis with D-penicillamine. The use of D-penicillamine in the treatment of rheumatoid arthritis is known to be complicated by the development of various glomerulonephritides. However, in this report we describe for the first time the development of IgM glomerular alterations consistent with a nephropathy in a patient undergoing D-penicillamine therapy.

Arthritis, Rheumatoid↗
PubMed1986

Providing health care for low-income children: reconciling child health goals with child health financing realities.

The goal of equitable access to health care continues to be elusive for poor children. Medicaid, the major source of financing such care, has been eroded by a series of actions by the administration and the Congress. A survey of the Medicaid-based EPSDT (Early and Periodic Screening, Diagnosis, and Treatment) programs in the fifty states pinpoints shortcomings in adequate financing and sound standards of practice. Reconciling child health goals with program realities will require new federal and state initiatives.

Aid to Families with Dependent Children↗
PubMed1985

Molecular defect in processing alpha-fucosidase in fucosidosis.

In normal human skin fibroblasts, an enzymatically active 53,000-dalton form of alpha-fucosidase is processed to a 50,000-dalton mature form. Endoglycosidase-H treatment of [35S]methionine pulse-chase labelled material immunoprecipated with a polyclonal antibody to alpha-L-fucosidase (Andrews-Smith & Alhadeff, Biochim. Biophys. Acta 715: 90-96 (1982)) indicated the removal of a single N-linked oligosaccharide unit from both precursor and mature form of alpha-L-fucosidase. Tunicamycin pretreatment of normal fibroblasts indicated that no other N-linked oligosaccharide units were present. Studies on fibroblasts from patients with less than 5% of normal alpha-L-fucosidase activity (fucosidosis) showed 8 of 11 patients synthesized no detectable alpha-fucosidase protein whereas 2 synthesized normal amounts of 53,000 dalton precursor, none of the mature 50,000 dalton form was detectable and one contained small amounts of cross-reacting material. This is the first evidence for processing of alpha-L-fucosidase in cells and the first precise evidence of a molecular defect in fucosidosis.

Cells, Cultured↗