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Biomedical subjects

J Hudson

Publications and source records attributed to J Hudson.

At least 91 records · Page 5Linked to original sources

Adherence to medical regime and related factors in youngsters on dialysis.

A pilot study is reported in which 18 children in end-stage renal failure, undergoing either haemodialysis or continuous ambulatory peritoneal dialysis were assessed with regard to adherence to their treatment regime. Measures were used to assess level of depression, locus of control and social desirability. Adherent behaviour was significantly related to high social desirability, and a shorter length of time on dialysis. There was no relationship between adherence and depression or locus of control.

Adjustment Disorders↗

Effect of an inhibitor of DNA methylation on T cells. I. 5-Azacytidine induces T4 expression on T8+ T cells.

Maturing thymocytes express a series of cell surface glycoproteins which can be identified by monoclonal antibodies. The stage II or common thymocyte expresses the phenotype T4+T8+T6+T3-. In response to unknown signals, but presumably involving interactions with products of the major histocompatibility complex, the thymocyte suppresses either the T8 or T4 gene, becoming committed to the T4+T8- or T4-T8+ phenotype. With maturation, the thymocyte also becomes T6-T3+. To study whether DNA methylation may be involved in regulating expression of these determinants in mature T cells, we treated cloned interleukin 2-dependent T8- and T4-bearing T cells with 5-azacytidine (5-azaC), a nucleoside analog which inhibits methylation of newly synthesized DNA. In this report, we show that T8+ T cells treated with 5-azaC express the phenotype T8+T4+T6-T3+. Treatment of the same cells with hydroxyurea, an inhibitor of DNA synthesis, failed to induce T4 on T8+ cells. These results suggest that expression of the T4 gene may be suppressed by DNA methylation in mature T8+ cells.

Antigens, Differentiation, T-Lymphocyte↗

Specific in vitro adenylylation of the simian virus 40 large tumor antigen.

Incubation of the simian virus 40 (SV40) large tumor antigen (T) from either transformed or lytically infected cells with adenosine [8-3H]-, [alpha-32P]-, or [alpha-[35S]thio]-triphosphate in the presence of Mg2+ resulted in its labeling as defined by the appearance of an intact, appropriately immunoreactive band in NaDodSO4/polyacrylamide gels. Radioactivity remained associated with the protein after boiling in buffer containing 3% NaDodSO4, and 2-mercaptoethanol as well as after heating in 0.1 M HCl, 0.1 M NH4OH, or hydroxylamine, but it was dissociated after incubation in 0.1 M NaOH at 37 degrees C. After limited boiling of gel-purified [alpha-32P] ATP + T complex in 5.6 M HCl, o-[32P]phosphoserine was released, and snake venom phosphodiesterase or 0.5 M piperidine treatment of such a complex resulted in the liberation of [alpha-32P]AMP. The reaction proceeded when either purified, soluble T or insoluble, specifically immunoprecipitated antigen was used as substrate. ATP and dATP were the preferred nucleotide substrates by comparison with the other six standard ribonucleoside or deoxynucleoside triphosphates. Partial tryptic digests of T + [alpha-32P]ATP complexes revealed the presence of a single labeled peptide of Mr approximately equal to 12 - 14 X 10(3), and after exhaustive digestion, there was a single radioactive spot in the fingerprint. These data indicate that T can be adenylylated at a specific seryl residue(s) in a limited portion of the protein surface. Furthermore, adenylylation appears to be reversible and to proceed by a pyrophosphorylytic mechanism, since the nucleotide was released from the protein following incubation of adenylylated T with Mg2+, sodium pyrophosphate, and poly(dT).

Adenosine Triphosphate↗

Rhinosporidiosis: ultrastructural study of an infection in South Carolina.

We have morphologically described and ultrastructurally analyzed Rhinosporidium seeberi, the causative agent of rhinosporidiosis, obtained from a nasal polyp of a man who had never traveled to India or Ceylon. The morphology, endosporulation phases, and cell wall were similar to those in previously described infections. A common etiology is suggested and potential therapy is discussed.

Adult↗

The effect of isoproterenol and hydroxyurea on the presence of ubiquitin and protein A24 in the rat salivary gland.

The in vivo administration of hydroxyurea for 12 h counteracts DNA synthesis and cell cycling stimulated by 72 h of isoproterenol treatment in rat salivary gland, as determined by fluorescence-activated flow cytometry. Hydroxyurea has little effect on [3H]leucine incorporation (protein synthesis) of the nuclear proteins soluble in 0.35 M NaCl, when examined by polyacrylamide gel chromatography and autoradiography from electrostatically sorted nuclei of (G0 + G1) and (G2 + M) phases of the in vivo cell cycle. Differential incorporation of [3H]leucine into nuclear proteins was observed during various phases of the cell cycle. Proteins 'X' and 'Z', observed in stained gel chromatographs of the 0.35 M NaCl-soluble nuclear proteins, were identified by biochemical analyses as ubiquitin and protein A24, respectively. Ubiquitin appeared transiently while A24 increased in gel chromatograms concomitant with progressive quiescence of the salivary gland induced by hydroxyurea.

Amino Acids↗

Immune regulation in myasthenia gravis: evidence for an increased suppressor T-cell population.

The production of anti-acetylcholine receptor antibodies in myasthenia gravis represents a persistent and unexplained break in self-tolerance. The studies reported here demonstrate an altered regulatory T-cell population with an increase in the percentage of circulating T-suppressor cells as defined by two independently developed murine monoclonal antibody markers. Leu 2a- and OKT8a-positive cells were significantly increased within the T-cell population in myasthenia gravis (25.0 +/- 6.4% versus 20.7 +/- 2.9% and 34.9 +/- 7.0% versus 26.0 +/- 3.2%, respectively) compared to an age- and sex-equivalent group. In addition, the circulating total T-cell population was reduced in myasthenia gravis. Patients with symptomatically uncontrolled disease (with or without immunosuppression) demonstrated significantly altered ratios of helper to suppressor T-cells, while patients whose myasthenia symptoms were controlled did not differ from normal subjects.

Adolescent↗

Sensitization of mice to methylphenidate.

Mice that received five daily injection of methylphenidate HCl, 10-75 mg/kg, showed an increased running response to methylphenidate, cocaine, and amphetamine. Sensitization to methylphenidate persisted for at least 50 days. Repeated IP injections of methylphenidate into mice with unilateral striatal lesions increased ipsilateral turning in response to methylphenidate, but decreased contralateral turning after apomorphine. The climbing response to apomorphine in intact, methylphenidate-sensitized mice was also decreased. There was no change in either basal or dopamine-stimulated adenyl cyclase activity in the striata of sensitized mice, but there was a 36% increase in the specific binding of haloperidol. The rate of turnover of striatal dopamine was increased in sensitized mice. These results suggest that pretreatment with methylphenidate may alter the sensitivity of presynaptic dopamine receptors.

Adenylyl Cyclases↗

Childhood immunization 1979. Disturbing statistics for metropolitan Sydney.

Twenty-seven per cent of children (24 out of 90) born consecutively in an inner-city hospital had not completed their primary courses of immunization at the end of the first year of life. Many of the parents of these children had no knowledge of how many doses of vaccine their children required. When 578 schoolchildren aged 12 years were studied, only 40% of these were found to be immune to all three poliovirus serotypes and 12% were not immune to diphtheria. The proportion of children who were not immune to diphtheria varied greatly, and was 24% in one school. The reasons for these low levels of immunity are discussed, and several recommendations are made. It is suggested that a standard immunization record card or book be adopted throughout Australia, and that this card be issued to the newborn child. It is also suggested that consideration be given to the introduction of laws which require that evidence of immunization (or certification of exemption from immunization) be presented at the time of school entry. In the meantime, mopping-up programmes should be conducted in schools where herd immunity is low and a poliomyelitis vaccine (Sabin) booster should be recommended for all children at the age of 12 years.

Australia↗

Intensive care nursing requirements: resource allocation according to patient status.

Intensive care nursing allocation seemingly has been a negotiated solution to a never ending battle: an arbitrary nursing/patient ratio. To correct this deficit, a prospective study was proposed to quantitate the time duration of sufficient intensive care to match the severity of illness. A comprehensive list of all nursing actions was compiled and timed. Thereafter, frequencies were observed according to global classifications: serious, critical, or crisis. A simple classification system separates the hourly requirement: serious = 2:1 patient/nurse ratio, critical = 1.0:0.75 full time nursing, and crisis = 1.0:1.2 patient/nurse ratio (or single nurse requires assistance). The increased requirements are created by increased need for ICU skills: vital signs = 1 hour for serious patients, 4 hours for critical, and a maximum of 10 hours for crisis patients (90% crisis patients has pulmonary artery and arterial catheters). Other categories of increased nursing time reflect ventilatory support, increased number of continuous and intermittent medications, etc. Global assessment (serious, critical, or crisis patient status) can be quantitated in terms of nursing hours actually required. Objective, rational, and variable patient/nurse ratios can be easily and accurately achieved in this manner. Staffing requirements and allocation of positions can be objectively quantitated.

Humans↗

Porcine calcitonin in the treatment of Paget's disease of bone: experience with 32 patients.

Thirty-two patients with osteitis deformans were treated with porcine calcitonin for 240 patient-months. Relief of pain occurred in 10 patients, while a fall in the serum alkaline phosphatase level was observed in 22 out of 24 patients whose treatment lasted for more than two weeks. Pain relief occurred predominantly in patients with pain in the lower limbs, although not all patients with lower limb pain showed improvement. Side effects, usually mild in nature, were reported by half the patients. Antiporcine calcitonin antibodies were detected in sera of six out of 14 patients. The presence of circulating antibodies seemed unrelated to the effect of therapy or to the occurrence of side effects.

Adult↗