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Biomedical subjects

J Phelan

Publications and source records attributed to J Phelan.

At least 55 records · Page 3Linked to original sources
PubMed1988

Patellofemoral joint motion: evaluation by ultrafast computed tomography.

Patellofemoral maltracking is a recognized cause of peripatellar pain. Measurements of the patellofemoral relationships during active motion are not available, and clinicians currently rely on observation, palpation, and static radiographic images to evaluate the symptomatic patient. Ultrafast computed tomography (ultrafast CT) offers objective observations of the dynamic influences of muscle contraction on the patellofemoral joint as the knee is actively moved through a range of motion from 90 degrees flexion to full extension. This study reports our initial observations and establishes a range of normal values so that patients with a clinical suspicion of patellar maltracking may be evaluated.

Adult↗
PubMed1988

Septic shock during pregnancy.

A multiinstitutional review of 10 pregnancies complicated by septic shock was undertaken to identify the clinical characteristics and hemodynamic alterations associated with this condition. Prolonged rupture of membranes with the subsequent development of chorioamnionitis or postpartum endometritis were risk factors that commonly preceded the diagnosis of septic shock. The majority of septic shock cases occurred during the puerperium. There were two maternal deaths in this selected series. Associated complications included pulmonary edema, adult respiratory distress syndrome, disseminated intravascular coagulation, pulmonary emboli, and cardiac arrest. The primary hemodynamic derangements were reduced systemic vascular resistance with depressed myocardial function. The mean initial systemic vascular resistance index in eight surviving women was 885 +/- 253 dyne.sec/cm5.m2. Despite an overall presenting cardiac index of 4.20 +/- 2.01 L/min/m2, five patients (50%) had evidence of myocardial depression based on analysis of their left ventricular function curves. Mean arterial pressure, systemic vascular resistance, and left ventricular stroke work index all showed significant improvement after therapy. A hemodynamic algorithm based on volume therapy, inotropic agents, and peripheral vasoconstrictors is offered. This therapeutic approach is designed to optimize cardiac performance and maintenance of organ perfusion in the critically ill patient with septic hypotension during pregnancy.

Blood Pressure↗
PubMed1988

Dentists' knowledge, case-finding behavior, and confirmed diagnosis of oral cancer.

A questionnaire was developed for dental general practitioners that was used to measure three types of clinician knowledge believed to be central to the early detection and management of oral cancer. Oral cancer management issues (case-finding behavior and clinician knowledge of patient outcomes) were also studied. The hypothesis that clinician knowledge is associated with oral cancer case-finding behavior could not be validated, but the hypothesis that clinician case-finding behavior is associated with knowledge of confirmed oral cancer or precancerous diagnoses was substantiated.

Analysis of Variance↗
PubMed1987

Fifteen years of experience with antepartum fetal testing.

The introduction of antepartum fetal heart rate testing occurred in the very early 1970s. This article describes the evolution of testing within the Los Angeles County/University of Southern California Medical Center and encompasses a 15-year time period between 1971 and 1985. During this time approximately 200,000 patients were delivered of their infants. Fetal surveillance increased from less than 1% to current levels of 16% of patients. The antepartum fetal death rate was evaluated as a measure of evaluating the usefulness of antepartum testing. The fetal death rate after antepartum testing in selected high-risk patients was significantly less than that found in those patients not tested. The questions that might be raised regarding broader application of this technique and potential benefits are stated.

California↗
PubMed1987

Vitamin A and tumor recurrence in bladder cancer.

Results are presented from an investigation concerning the effects of vitamin A on tumor recurrence in a group of 102 patients having early-stage bladder cancer. An odd's ratio of 1.34 was found for tumor recurrence between high and low consumers of vitamin A (p greater than 0.05). Moreover, the rate of tumor recurrence per 1,000 person-months at risk was found to be 1.8 times higher among low, relative to high, consumers of vitamin A (p less than 0.05). While these results are encouraging, larger data sets need to be assembled and analyzed before any definitive conclusions can be reached.

Humans↗
PubMed1987

Clonal analysis of the T-cell response of mice to herpes simplex virus: correlation between lymphokine production in vitro and the induction of delayed-type hypersensitivity and antiviral activity in vivo.

The properties of two morphologically distinct L3T4+, Lyt2- "helper" T-cell clones specific for herpes simplex virus were investigated. Both of the clones produced IL-3 and interferon, but neither produced IL-2. Clone D6.6 produced macrophage agglutinating factor, a fibronectin-like lymphokine, and also a delayed hypersensitivity (DH) response when injected locally into syngeneic mice. Despite the presence of a DH producing clone and a non-DH producing clone, both were able to reduce the local virus titre to an equivalent degree. It is suggested that this protective activity is associated with the production of interferon-gamma. The significance of these results to mechanisms of protection against herpes simplex virus in vivo is discussed.

Animals↗
PubMed1987

Different roles for L3T4+ and Lyt 2+ T cell subsets in the control of an acute herpes simplex virus infection of the skin and nervous system.

Rat monoclonal antibodies were used to deplete selectively Lyt 2 (cytotoxic) and L3T4 (helper) T cell populations in vivo. These antibodies produced greater than 95% depletion of the respective T cell subset as determined by fluorescent antibody and cytofluorographic analyses. Antibody-treated mice were infected in the ear pinna with herpes simplex virus (HSV) and the induction of virus-specific T cell and antibody responses were monitored during the acute infection. Lyt 2-deficient mice produced delayed hypersensitivity and HSV-specific antibodies comparable to those in untreated animals. However, major histocompatibility complex class I-restricted T cell killing was abolished. In contrast, L3T4-deficient animals failed to produce either primary delayed hypersensitivity response or specific antibodies to the virus, but cytotoxic T cell responses were induced and even augmented in comparison with infected, normal animals. This observation clearly demonstrates that Lyt 2 cytotoxic T cells can be induced in a helper T cell-deficient environment. The ability of T cell subset-deficient mice to clear infectious virus was investigated in the skin of the ear and the part of the nervous system innervating the site of infection. L3T4-deficient animals showed a markedly delayed clearance of virus from the ear and also had a more florid infection of the nervous system. However, Lyt 2-deficient mice cleared the infection in the ear normally, but a severe infection of the nervous system was still observed. The implication of these observations to the pathogenesis of this virus is discussed.

Animals↗
PubMed1985

Computerized 24-hour esophageal pH monitoring: a new ambulatory technique using radiotelemetry.

A computerized telemetric system using a portable microprocessor receiving unit has been designed for clinical use in ambulatory 24-hour esophageal pH monitoring. The receiving unit can be used with either a pH-sensitive radiotelemetry pill or a standard intraesophageal pH probe. Esophageal pH data is collected under microprocessor control while the patient is in the usual home or work environment. Computerized plotting and analysis of the compiled pH data is performed at the conclusion of the ambulatory testing. The system has been successfully used in patients with symptoms of esophageal reflux and healthy volunteers with no symptoms. The development of a computer-based radiotelemetry system for prolonged monitoring of esophageal pH represents a substantial advance in existing investigational technology. It allows the use of new radiotelemetric techniques of esophageal pH recording with increased patient comfort and acceptance over a 24-hour ambulatory testing period. Microprocessor control of both data collection and analysis allows rapid interpretation of complex 24-hour esophageal pH tracings and greatly facilitates the performance of esophageal pH monitoring as a routine clinical investigation.

Adult↗
PubMed1984

The role of nonstress tests, fetal biophysical profile, and contraction stress tests in the outpatient management of insulin-requiring diabetic pregnancies.

Antepartum fetal surveillance methods applicable in a home glucose-monitored population of pregnant diabetic women have been evaluated. A testing sequence of nonstress heart rate testing, backed up by either the fetal biophysical profile or contraction stress testing employed at a twice weekly interval, in 107 outpatients was compared with the management of 140 historic control patients by weekly nonstress tests and daily plasma estriols. There were 617 of 672 (91.8%) reactive nonstress tests in outpatients compared to 566 of 626 (90.4%) reactive tests in hospitalized control patients. Of 13 contraction stress tests performed in the outpatient group, only one was positive. Although 2,670 estriol determinations were done on hospitalized control patients, none was used for outpatients. No losses were attributed to unexplained antenatal stillbirth in either group. A fetal biophysical score of 8 was found to be at least as reliable as a reactive nonstress test. Antenatal surveillance in the well-controlled, insulin-requiring diabetic woman can be safely achieved with a testing sequence that consists of twice weekly nonstress tests backed up by the fetal biophysical profile and contraction stress tests.

Diabetes Mellitus, Type 1↗
PubMed1982

Pathogenesis of herpes simplex virus in congenitally athymic mice: the relative roles of cell-mediated and humoral immunity.

Athymic nude (nu/nu) mice were inoculated in the ear pinna with 10(4) p.f.u. herpes simplex virus type 1 (strain SC 16). Initially, the virus was observed to replicate in the pinna, spreading via a neurological route to the dorsal root ganglia, spinal cord, brain and adrenal glands. Following the transfer of lymphoid cells from day 7 herpesvirus-infected hairy immunocompetent donors into infected nude mice, virus was not isolated from the pinna and nervous system of the majority of the mice. The passive transfer of neutralizing polyclonal anti-herpesvirus serum or neutralizing monoclonal anti-gp D serum did not reduce infectivity in the pinna, but markedly reduced the amount of virus in the ganglia and spinal cord. These data suggest that neutralizing antibodies play an important role in restricting the movement of virus to the nervous system, whereas cell-mediated immune (CMI) mechanisms are essential for eliminating virus from the pinna.

Animals↗
PubMed1981

Cell-mediated immunity in herpes simplex virus-infected mice: H-2 mapping of the delayed-type hypersensitivity response and the antiviral T cell response.

An adoptive transfer system was used to investigate the H-2 restriction of delayed-type hypersensitivity (DTH) to herpes simplex virus. A successful DTH transfer was achieved when donor and recipient were compatible at the I-A region, with K and D region compatibility unnecessary. However, the rapid clearance of infectious virus from the inoculation site was found only when the donor and recipients were compatible at H-2K (and presumably D) and I-A regions.

Animals↗
PubMed1981

Tolerance and immunity in mice infected with herpes simplex virus: studies on the mechanism of tolerance to delayed-type hypersensitivity.

Tolerance to delayed-type hypersensitivity is produced in mice following an intravenous injection of herpes simplex virus. This form of tolerance is produced early on, following simultaneous injections of virus subcutaneously and intravenously, and is long lasting (greater than 100 days). The early tolerance mechanism is resistant to high doses of cyclophosphamide and is not transferable by serum or spleen cells taken after 7 days. However, spleen cells taken at 14 days onwards inhibit the induction of delayed hypersensitivity when transferred to normal syngeneic recipients. These cells are T lymphocytes and are specific for the herpes type used in the induction.

Animals↗
PubMed1980

Sodium molybdate increases the amount of progesterone and estrogen receptor detected in certain human breast cancer cytosols.

When sodium molybdate is added at a final concentration of 20 mM, additional 8S and 4S progesterone (3H-R5020) receptor can be detected in the cytosols from a number of human breast cancers. Additional estrogen receptor also could be measured in some cytosols, and a quantitative temperature-dependent conversion of 8S to 4S binding molecules achieved. Sodium molybdate also prevented the loss of binding activity that occurred when cytosols were incubated at 30 degrees in the absence of added estradiol. In addition to increasing the amount of progesterone receptor, and to a lesser extent estrogen receptor that may be detected, elicidation of the mechanism by which this salt stabilized receptors should contribute to further understanding of how cytosol steroid receptor content and function is regulated.

Breast Neoplasms↗
PubMed1977

Criteria of the silhouette sign.

The silhouette sign is a reliable sign, distinguishing anterior lung lesions from posterior or lower lung lesions. This paper has shown that the mechanism by which this occurs is not based on anatomical contact between intrathoracic structures, but on principles governing radiographic contrast, and the perception of that contrast.

Child, Preschool↗