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Biomedical subjects

C Noonan

Publications and source records attributed to C Noonan.

12 recordsLinked to original sources
PubMed1999

Monocular and binocular depth discrimination thresholds.

BACKGROUND: Measurement of stereoacuity at varying distances, by real or simulated depth stereoacuity tests, is helpful in the evaluation of patients with binocular imbalance or strabismus. Although the cue of binocular disparity underpins stereoacuity tests, there may be variable amounts of other binocular and monocular cues inherent in a stereoacuity test. In such circumstances, a combined monocular and binocular threshold of depth discrimination may be measured--stereoacuity conventionally referring to the situation where binocular disparity giving rise to retinal disparity is the only cue present. A child-friendly variable distance stereoacuity test (VDS) was developed, with a method for determining the binocular depth threshold from the combined monocular and binocular threshold of depth of discrimination (CT). METHODS: Subjects with normal binocular function, reduced binocular function, and apparently absent binocularity were included. To measure the threshold of depth discrimination, subjects were required by means of a hand control to align two electronically controlled spheres at viewing distances of 1, 3, and 6m. Stereoacuity was also measured using the TNO, Frisby, and Titmus stereoacuity tests. BTs were calculated according to the function BT= arctan (1/tan alphaC - 1/tan alphaM)(-1), where alphaC and alphaM are the angles subtended at the nodal points by objects situated at the monocular threshold (alphaM) and the combined monocular-binocular threshold (alphaC) of discrimination. RESULTS: In subjects with good binocularity, BTs were similar to their combined thresholds, whereas subjects with reduced and apparently absent binocularity had binocular thresholds 4 and 10 times higher than their combined thresholds (CT). The VDS binocular thresholds showed significantly higher correlation and agreement with the TNO test and the binocular thresholds of the Frisby and Titmus tests, than the corresponding combined thresholds (p = 0.0019). CONCLUSION: The VDS was found to be an easy to use real depth (distance) stereoacuity test. The method described for calculating the BT provides one simple nonlinear solution for determining the respective contributions of binocular and monocular (MT) depth discrimination to the combined depth threshold.

Adolescent↗
PubMed1998

Congenital infantile fibrosarcoma: a case study.

Congenital infantile fibrosarcoma (CIFS) is a rare soft-tissue malignancy most commonly involving the extremities. Metastases are rare; however, local recurrence is common. Because the tumor is so rare and clinical experience is lacking, both diagnosis and treatment are difficult. The complex planning and implementation of neonatal and oncologic care require ongoing collaboration between both nursing specialties. This case study discusses the pathophysiology, diagnosis, and management of an infant with CIFS, with emphasis on the nursing care of the patient and family.

Female↗
PubMed1996

Study of receptor-mediated neurotoxins released by HIV-1-infected mononuclear phagocytes found in human brain.

Although there is growing evidence that neurotoxic molecules produced by HIV-1-infected mononuclear phagocytes damage neurons, the precise mechanisms of neuronal attack remain uncertain. One class of cytotoxin involves neuronal injury mediated via the NMDA receptor. We examined blood monocytes and brain mononuclear cells isolated at autopsy from HIV-1-infected individuals for the ability to release NMDA-like neuron-killing factors. We found that a neurotoxic amine, NTox, was produced by blood monocytes and by brain mononuclear phagocytes infected with retrovirus. In vivo injections of minute quantities of NTox produced selective damage to hippocampal pyramidal neurons. NTox can be extracted directly from brain tissues infected with HIV-1 and showed structural features similar to wasp and spider venoms. In contrast to NTox, HIV-1 infection did not increase the release of the NMDA excitotoxin quinolinic acid (QUIN) from mononuclear cells. Although we found modest elevations of QUIN in the CSF of HIV-1-infected individuals, the increases were likely attributable to entry through damaged blood-brain barrier. Taken together, our data pinpoint NTox, rather than QUIN, as a major NMDA receptor-directed toxin associated with neuro-AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Immunization outreach at Income Support Centers, New York City, 1992-1993.

An increase in measles occurred in New York City (NYC) during 1989-1990, affecting primarily unvaccinated preschool-aged children. Many of these children were also enrolled in Aid to Families with Dependent Children (AFDC) programs. To determine the immunization status of children receiving AFDC, immunization records were reviewed at three NYC income support centers. Records were assessed for vaccination eligibility on the day of the visit and at various ages. Seventy-six percent of the children were found eligible for vaccination on the day of their visit. Vaccination levels at two years of age were among the lowest measured in New York. Future immunization efforts should be directed toward this population.

Aid to Families with Dependent Children↗
PubMed1993

Survival and mortality patterns of an acquired immunodeficiency syndrome (AIDS) cohort in New York State.

The survival experience and causes of death of acquired immunodeficiency syndrome (AIDS) patients were studied using a cohort of 3,699 AIDS patients in New York State, excluding New York City, whose illness was diagnosed before January 1990 at age 13 years or older. The median length of survival for all cases was 11.5 months, and survival increased over time from 5.3 months pre-1984 to 9.3 months in 1984-1986 and to 13.2 months in 1987-1989. In a Cox proportional hazards model, risk of dying was higher for persons aged 35 years or more at diagnosis and for persons with a diagnosis other than Pneumocystis carinii pneumonia or Kaposi's sarcoma whose illness was diagnosed before 1986. In this AIDS cohort, 2,834 (77 percent) persons died before 1991; 87 percent of the death certificates listed human immunodeficiency virus (HIV)/AIDS or an AIDS indicator disease as one of the multiple causes of death. The finding that 13 percent of the death certificates did not mention AIDS/HIV suggests that use of death certificates alone to count HIV-related deaths would result in an undercount. The recent expansion of the federal AIDS case definition is expected to add HIV-infected persons who die from conditions, such as recurrent pneumonia, that were not included in the earlier definition.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Hepatitis B virus DNA in peripheral-blood mononuclear cells in chronic hepatitis B after HBsAg clearance.

In this study, peripheral-blood mononuclear cells from patients with chronic hepatitis B and spontaneous or therapy-induced disappearance of HBsAg were examined for HBV DNA. Samples were evaluated by in situ hybridization and polymerase chain reaction both before and after clearance of HBsAg. By in situ hybridization, positive signals were observed in 2 of 13 samples collected after HBsAg loss, in 8 of 15 samples before HBsAg loss and in 0 of 4 control patients without serological markers of active or prior HBV infection. When polymerase chain reaction analyses were performed, HBV DNA was detected in 5 of 12 HBsAg-negative samples and 10 of 15 HBsAg-positive samples from the study group. Testing of mononuclear cells after disappearance of HBsAg revealed that two of eight patients were HBV DNA positive by in situ hybridization and by polymerase chain reaction, whereas two additional patients were positive by polymerase chain reaction alone. Mononuclear cell-associated HBV DNA was detected between 2 and 9 mo after the disappearance of circulating HBsAg by in situ hybridization and as long as 4 yr later by polymerase chain reaction. These data indicate that patients who have undergone HBsAg seroconversion may nonetheless harbor HBV DNA in their peripheral-blood mononuclear cells for prolonged periods.

Adult↗
PubMed1991

Is a single tricyclic antidepressant trial an active treatment for psychotic depression?

1. A retrospective chart review of 256 consecutively admitted depressed inpatients assessed their treatment response to optimal somatic therapy. 2. There were no differences in treatment response between patients with Major Depressive Episode (MD) and Major Depression with Psychosis (MD-P). 3. In addition, twenty-six studies were reviewed to clarify the role of tricyclic antidepressants (TCA) in the treatment of MD-P. The authors conclude from this literature review that TCA's should not be considered an active treatment for MD-P patients.

Adult↗
PubMed1973

Effects of actinomycin D and ultraviolet and ionizing radiation on Pichinde virus.

Actinomycin D (0.05 mug/ml) suppresses the synthesis of ribosomal RNA of baby hamster kidney (BHK21) cells. The production of infectious Pichinde virus was enhanced in the presence of actinomycin D, although the production of virus particles was not substantially different from cultures inoculated in the absence of the drug. By prelabeling BHK21 cells with (3)H-uridine and then allowing the virus to replicate in the presence of actinomycin D, it was possible to show that ribosomal RNA synthesized prior to infection was incorporated into the virion. A single-hit kinetics of inactivation of Pichinde virus was observed with ultraviolet light, suggesting that the virus contains only a single copy of genome per virion. Comparison of the inactivation kinetics by gamma irradiation of Pichinde virus with Sindbis and rubella virus indicated that the radiosensitive genome of Pichinde virus was about 6 x 10(6) to 8 x 10(6) daltons. This value is greater than the 3.2 x 10(6) daltons which was estimated by biochemical analysis. One possible explanation considered is that the ribosomal RNA of host cell origin is functional and accounts for the differences in genome size estimated by the two methods.

Animals↗