Search PubMed⌕ Search

Biomedical subjects

J Sullivan

Publications and source records attributed to J Sullivan.

At least 163 records · Page 9Linked to original sources
PubMed1989

Plasticity of neuronal receptors.

This article describes ways in which receptors, key components of signal propagation through a synapse, can mediate changes in that propagation. Changes occur at four levels: in the signal-transducing capability of a single receptor molecule, in the number of receptors per cell, in the subcellular placement of receptor molecules, and in the cytoarchitecture of receptor-rich regions. The ability of receptors to shift between different desired states is called plasticity, and such shifts can be long-lived as well as transient. In this article we focus on neuronal receptors, although key findings from a variety of cell systems are reported. Neuronal receptor plasticity may have a special role in the assembly as well as the adaptability of the nervous system.

Animals↗
PubMed1989

Post mortem findings in a patient with 46,XX,fra(2)(q13).

A severely mentally retarded girl who suffered from grand mal seizures, myoclonic jerking and ataxia died at 18 years of age. Chromosome studies, before and after death revealed a fragile site on chromosome 2q13, the expression of which was greater in peripheral blood than in fibroblasts on two occasions. Post mortem findings did not reveal any abnormality which could be attributed to this fragile site.

Acute Disease↗
PubMed1989

High school students' perceptions of nursing as a career: a pilot study.

A pilot survey of 300 high school junior students was implemented to elicit their perceptions of nursing and to explore the relationship between the experience of having a nursing role model and the decision to consider nursing as a career. The results indicated that the majority of students in the sample were aware of the caring and helping aspects of nursing, but there seemed to be a lack of knowledge about expanded roles and opportunities for advancement. High school students had significantly different mean opinion scores according to their sex (F = 17.03, p less than 0001) and the decision to consider nursing as a career (F = 10.00, p less than 002). There appeared to be a significant relationship between the experience of having a nurse role model and consideration of nursing as a career option (chi 2 = 8.23, p less than .0041). These findings have important implications for recruitment of young people into the nursing profession.

Adolescent↗
PubMed1989

Brain resuscitation. Nursing interventions.

Critical care nurses who participate in brain resuscitation are constantly challenged to meet the dynamically changing demands of cerebral preservation therapy. New therapies are continuously being developed, experimentally tested, and clinically implemented. Calcium channel blockers, hemodilution, free radical scavengers, and ventriculosubarachnoid perfusion of oxygenated fluorocarbon emulsions are therapies that are currently on the horizon in the field of brain resuscitation. Familiarity with these therapies and a discriminating understanding of their physiologic effects is required by the critical care nurse who seeks to actively participate as a member of the brain resuscitation team. The informed critical care nurse who participates in postcardiac arrest cerebral preservation is best prepared to perform the roles of bedside caregiver, patient advocate, and family liaison. This dynamic, unfolding, and as yet unpredictable field of brain resuscitation presents great challenges, possibilities, and potential rewards for critical care nursing.

Brain Ischemia↗
PubMed1988

Management of primary and metastatic renal cell carcinoma by transcatheter embolization with iodine 125.

The long-term results of the management of metastatic renal cell carcinoma by a radioactive interstitial implant seated by a transcatheter embolization technique were evaluated in 85 patients at risk at 2 years and 37 at 5 years. The 2-year survival rate was 33% and the 5-year survival rate was 32%. Patients with isolated skeletal metastases showed the best survival rate (2-year survival rate, 69%; 5-year survival rate, 60%). Isolated pulmonary, other parenchymal, and central nervous system (CNS) metastases showed a lower 2-year survival rate of 15%. Regardless of the site of metastases and the size of the primary, histologic grade appeared to have a substantial impact on the survival of our patients. The beneficial results of interstitial radiation therapy are attributed to reduction of tumor burden and possibly the stimulation of the host immune response that may initiate remission. The noticeably better results in patients with osseous metastases are attributed to the resolute treatment of all osseous metastases by additional interstitial iodine 125 (125I) infarct implants. Conversely, the poor results in patients with CNS and other parenchymal metastases may be based on the inability to treat such metastases with 125I interstitial infarct implants. In addition to clinical observations of weight gain and the cessation of pain and hematuria if present, remissions are heralded by normalization of the erythrocyte sedimentation rate, disappearance of tumor markers if present, and rise of beta interferon levels. The technique is advocated for the management of inoperable renal cell carcinoma with distant metastases.

Brachytherapy↗
PubMed1988

Function of neutral endopeptidase on the cell membrane of human neutrophils.

Intact human neutrophils hydrolyzed N-formyl-Met-Leu-[3H]Phe (fMLP) and released Leu-[3H]Phe, cleaving 45-50% of the peptide within 20 min at 37 degrees C. The dipeptide after its release was then hydrolyzed to free amino acids by a dipeptidase (EC 3.4.13.11). This activity, present in plasma membrane-enriched fractions of neutrophil lysates, was also inhibited over 90% by phosphoramidon, an inhibitor of neutral endopeptidase (NEP, EC 3.4.24.11). Dithiothreitol and EDTA inhibited the activity to a comparable degree, suggesting the requirement for a heavy metal cofactor. Bestatin and amastatin, inhibitors of aminopeptidases (but not human kidney NEP), did not inhibit the rate of fMLP degradation but prevented the production of free phenylalanine and enhanced the accumulation of Leu-Phe. Of other inhibitors, alpha 1-antitrypsin and alpha 2-macroglobulin slightly enhanced the rate of fMLP hydrolysis by neutrophils, and others tested were ineffective. Rabbit antiserum to homogeneous human kidney NEP reacted specifically with a 100-kDa protein present in sodium dodecyl sulfate-solubilized neutrophils. The Mr of this protein was slightly larger than that of the kidney enzyme in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antiserum incubated with intact cells specifically inhibited the degradation of fMLP over 70%. First, we confirm that NEP present on the plasma membrane cleaves fMLP at the Met-Leu bond; then the dipeptide Leu-Phe is cleaved by a dipeptidase. Finally, inhibition of NEP completely blocks fMLP-mediated chemotaxis. Thus, the enzyme may play an important role in modulating chemotactic responses.

Anti-Bacterial Agents↗
PubMed1988

Early events in target-cell lysis by cytotoxic T cells.

Using ratio-imaging fluorescence microscopy, we have investigated the changes in intracellular Ca2+ [( Ca2+]i) that occurred in cytotoxic T lymphocytes (CTL) upon target-cell binding. This process resulted in a rapid increase in [Ca2+]i, which was localized in the region of the CTL in contact with the target cell. This increase was mediated both by influx from the external medium as well as by release from intracellular stores. Although the magnitude of the initial increase in [Ca2+]i was not dependent upon the presence of extracellular Ca2+, influx was necessary for sustained elevation of [Ca2+]i. Inasmuch as target-cell lysis by the CTL clone used is dependent on extracellular Ca2+, this suggests that a prolonged elevation of [Ca2+]i is necessary for lytic function. It was also shown that the increase in [Ca2+]i and its subsequent decay show several pulsations. The mechanism by which these variations are generated and their possible function is not known. Finally, a role for K+ efflux in the control of the antigen-induced increase in [Ca2+]i was demonstrated. Thus it is becoming clear that signal transduction in CTL is remarkably complex, involving several ionic species and second messengers.

Animals↗
PubMed1987

Propagation of differentiating normal human tracheobronchial epithelial cells in serum-free medium.

Serial-passage cultures of normal human tracheobronchial (TB) epithelial cells that exhibit functional differentiation have been established in serum-free medium supplemented with bovine pituitary extract (25 micrograms/ml), insulin (5 micrograms/ml), hydrocortisone (0.5 micrograms/ml), EGF (5 ng/ml), 10(-6)M each of ethanolamine and phosphoethanolamine, and antibiotics. The cells proliferated in this medium with a population doubling time of approximately 80 hours. Further, the passaged cultures retained differentiated morphology as evidenced by secretion of glycoproteins, binding of concanavalin A lectin, and presence of alcian blue and periodic acid Schiff-positive material in their cytoplasm. Ultrastructural observations further supported the functional epithelial nature of the cultures. Most cells exhibited characteristic microvilli on cell surfaces and showed junctional complexes between them. The cytoplasm contained a large number of perinuclear secretory vesicles, a characteristic feature of the differentiated cells. These cultures provide an excellent model to study factors that regulate synthesis and secretion of glycoproteins in normal human TB cells.

Adult↗
PubMed1987

The treatment of secondary orgasmic dysfunction II.

This study investigated the impact of group treatment on women with secondary orgasmic dysfunction and their partners. Eleven couples received 4 hours of basic sex education, after which seven of the couples received a Combination treatment format consisting of communication skills followed by sexual skills, while four of the couples received the opposite sequence. No significant differences were found between the two sequences. When compared with similarly recruited control couples in a previous study, a significantly greater number of treated women reached or exceeded the 50% criterion for coital orgasmic functioning after treatment. Couples who reported a better relationship adjustment prior to treatment reported a significantly greater gain in total sexual harmony than did less adjusted couples. Across the treatment conditions, women who had reached coital orgasm prior to treatment reported a significantly greater increase in relationship adjustment between the post-sex education and 6-month follow-up testing periods than women who had never reached coital orgasm. Some discrepancies in outcome were found in comparison with our earlier study, suggesting that subject heterogeneity may influence differential outcomes.

Adult↗
PubMed1986

Utility of the group coefficient of variation in predicting speech-motor equivalence in normal and articulatory disordered speakers.

Coefficients of variation of EMG signals from the orbicularis oris superior, orbicularis oris inferior, and masseter muscles of normal 4- and 8-yr.-olds and adults and of articulatory disordered 8-yr.-olds suggests that development of speech motor equivalence is individualized, muscle-dependent, and affects all children. Age-related differences were noted. Group data did not predict individual values.

Age Factors↗
PubMed1986

Mutagenesis and repair of DNA damage caused by nitrogen mustard, N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU), streptozotocin, and mitomycin C in E. coli.

Cytotoxicity and mutagenesis by streptozotocin, BCNU, nitrogen mustard, and mitomycin C were evaluated in E. coli mutants deficient in SOS repair, SOS-mediated mutagenesis, the adaptive response, and mutants that engage in aberrant mismatch repair. The results demonstrate that premutagenic lesions are caused by nitrogen mustard, BCNU and streptozotocin that are not repaired by ada or recognized by umuDC. Further, recA mutants were hypomutable after exposure to nitrogen mustard, BCNU, and streptozotocin compared to wild type. With the exception of the monofunctional nitrosourea, streptozotocin, both recA and uvrA gene products contribute to the repair of DNA damage caused by the alkylating agents tested. In the case of streptozotocin, although recA mutants were more sensitive than wild type, uvrA mutants were not. Moreover, while ada and alkA E. coli mutants showed increased sensitivity to streptozotocin, they were not more sensitive to the other alkylating agents evaluated.

Carmustine↗