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Biomedical subjects

L C Olson

Publications and source records attributed to L C Olson.

At least 19 recordsLinked to original sources
PubMed1996

Fine-needle biopsy of pediatric lesions: a three-year study in an outpatient biopsy clinic.

Diagnostic Cytology Laboratory, Inc., has an outpatient Fine Needle Biopsy Clinic, which evaluated 7,487 fine-needle biopsies (FNB) from January 1989 to February 1992. Two hundred eighty-eight (3.8%) of these specimens were collected from patients 19 years old or younger and this represents the largest study of this population in the scientific literature. The majority of these specimens were obtained from palpable masses in the head and neck region [lymph nodes (58.3%), thyroid (7.6%), and salivary gland (5.2%)] while a smaller number were collected from miscellaneous soft tissue (18.8%) and breast masses (10.1%). Thirteen (4.5%) (from 12 patients) were diagnosed as malignant by FNB and 275 (95.5%) (264 patients) were benign by FNB. This benign:malignant ratio (22:1) is significantly higher than has been reported from tertiary care institutions and is a reflection of the difference of this outpatient population. Two hundred nine of 276 patients (75.7%) had adequate follow-up, including 137 (49.6%) patients followed by observation, 48 (17.4%) patients followed by surgical biopsy, and 24 (8.7%) patients followed by some other modality: imaging studies, flow cytometry, or treatment. There was a single false positive diagnosis (a pilomatrixoma) and one (1) false negative interpretation (a cystic acinic cell carcinoma) resulting in a diagnostic sensitivity of 92.3% and a specificity of 99.6%. The positive predictive value was 92.3%, the negative predictive value was 99.6%, and the test efficiency was 99.3%. The utility, cost-effectiveness and uniqueness of the clinic population is discussed.

Adolescent↗
PubMed1995

Pertussis in the young infant.

Pertussis, one of the most communicable respiratory diseases, has a wide spectrum of severity, which generally decreases with age. Adults with waning immunity, who have subclinical pertussis, frequently infect nonimmunized or underimmunized children within the same household. High levels of pertussis activity persist, even in highly immunized populations. Infants less than 2 months of age have the highest attack rate and greatest morbidity and mortality. Serious complications include apnea, pneumonia, encephalopathy, and recurrence of coughing spasms with cyanosis. These complications further contribute to a protracted disease course in young infants. Although a decrease in the incidence of pertussis has occurred since the advent of active immunization in the United States, recent data show a striking resurgence in cases. Widespread transmission of disease, even in immunized individuals, and subclinical adult infection, which serves as a reservoir for disease in young infants, underscore the need for a more effective vaccine immunization strategy.

Humans↗
PubMed1992

Pyogenic arthritis associated with adjacent osteomyelitis: identification of the sequela-prone child.

We treated 96 cases of pyogenic arthritis from January 1, 1980, to December 31, 1990, 16 of whom had adjacent osteomyelitis. Presenting symptoms in the latter were indistinguishable from those in 80 cases of primary pyogenic arthritis with regard to involved joints, aspirate findings and pathogens; however, adjacent osteomyelitis patients tended to be younger and were more likely to be symptomatic more than 7 days and to have received prior antibiotics. Prompt joint drainage was done in 15 of 16 cases but adjacent osteomyelitis was recognized in only 5. Bone scan was misleading in 3 of the 4 cases where it was performed as part of the initial evaluation. Persistent pain, swelling and/or fever occurred in 9 patients, 6 of whom underwent further joint drainage. Radiographs were diagnostic in 1 patient at admission, 10 during hospitalization and in 5 at follow-up. Sequelae were found in 8 of 13 patients with bone and joint infections vs. 8 of 41 patients with primary joint infection. Patients with a positive culture from the hip or shoulder who had been pretreated with antibiotics had the worst prognosis. Osteomyelitis should be considered in patients who present with symptoms and signs of pyogenic arthritis for longer than 1 week, especially if they have received prior antibiotics. Earlier recognition and bone debridement may improve outcome.

Adolescent↗
PubMed1992

Complications of varicella requiring hospitalization in previously healthy children.

Between January 1, 1981, and December 31, 1990, 83 previously well children and 20 with stable underlying conditions were hospitalized because of complications of varicella. The mean hospital stay was 4.5 days and one child with pneumonia died. Skin or soft tissue infections and pneumonia were the most common complications. Central nervous system complications (15), dehydration (8) and Reye's syndrome (6) accounted for 75% of the nonsuppurative complications. Cellulitis (7), pneumonia (3) and encephalitis (3) were the most common diagnoses among the 20 children hospitalized greater than or equal to 7 days. No cases of Reye's syndrome were diagnosed after 1984. An increase in the number of soft tissue infections caused by Group A beta-hemolytic streptococci and involving an extremity was noted during the last 5 years. Chickenpox continues to cause significant morbidity in the pediatric population.

Adolescent↗
PubMed1991

Kidney allograft tolerance in primates without chronic immunosuppression--the role of veto cells.

Posttransplant infusion of specific donor bone marrow cells into ATG-treated recipients promotes long survival of allografts in the absence of immunosuppressive drug therapy. DBMC infusion also inhibits antidonor CTL activation in allograft recipients, a trend analogous to the veto phenomenon. The present studies investigated a hypothesis that veto activity in DBMC is involved in the induction of donor-specific unresponsiveness in rhesus monkey kidney transplant recipients given ATG and DBM. Normal monkey BMC were fractionated into subpopulations by depletion with mAbs and immunomagnetic beads. The unfractionated BMC and BMC subsets were tested for veto activity in in vitro MLR-induced CTL and for in vivo tolerance-promoting activity in ATG-treated monkey kidney transplant recipients. In MLR-induced CTL assays, BMC specifically suppressed CTL activity to PBL from the BMC donor. The suppression was mediated by a small population of BMC that expressed a CD2+, CD8+, CD16+, DR-, CD3-, CD38- phenotype. Results of in vivo studies showed a striking correlation with the in vitro results. ATG-treated recipients given either DR- DBMC or DR- CD3- DBMC infusions had significantly prolonged graft survival and a 40-50% incidence of long survivors over 150 days (P less than 0.001 vs. ATG controls). In contrast, in recipients given CD2- DBMC or DR- CD16- DBMC infusions, the tolerance-promoting effect of DBMC was absent, and there were no long-term survivors. The results also showed an association between long survival and suppressed in vivo antidonor CTL activity. Thus acute rejection and in vivo and in vitro antidonor CTL responses were suppressed by a minor subpopulation of DBMC with similar phenotypic markers. We suggest that a veto mechanism may control the induction phase of allograft tolerance in this model, providing a critical period of CTL silence to allow development of host immunoregulatory mechanisms necessary for maintaining graft tolerance.

Animals↗
PubMed1991

Persistent reduction of B virus (Herpesvirus simiae) seropositivity in rhesus macaques acquired for a study of renal allograft tolerance.

One hundred and two rhesus macaques were used in a study of renal allograft tolerance. Each animal was monitored serologically more than one time to determine its B virus (Herpesvirus simiae) antibody status. The follow-up period for some individuals was 3 years, extending from 1986 to 1989. The accumulated test results eventually provided an opportunity to retrospectively support a contention that a small research colony of rhesus macaques could become and remain B virus seronegative if the animals were housed individually, monitored periodically, acquired only if they were seronegative, and culled if they converted to positive status. It was also possible that the test results might disclose useful information about the influence of acute immunosuppression on the reliability of determining B virus antibody status by serologic methods, and help formulate guidelines for selecting donor-recipient pairs. A review of the serologic test results disclosed that antibody status before the initiation of experimental therapy, and subsequent seroreactivity, did not change throughout the experimental lifetime of 92 monkeys. The few exceptions were six juveniles that lost detectable antibody, and four other juveniles that converted to positive. Preliminary data suggested that total lymphoid irradiation (TLI) and splenectomy were associated with the loss of detectable antibody; however, further study is needed to establish the validity and significance of this association. No other unexpected or unexplained results were associated with concomitant periods of acute immunosuppression. The number of seropositive animals in the colony was reduced to three through attrition and culling by the end of 1989.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Childhood lawn dart injuries. Summary of 75 patients and patient report.

Lawn dart injuries account for an estimated 675 emergency department visits per year. Seventy-six patients are described herein. The victims ranged from 1 to 18 years of age and were predominantly male (male to female ratio is 3.1:1). The most common sites of injury were head (54%), eye (17%), and face (11%). Hospitalization was required for 54% (41/76) of these patients. Sequelae included unilateral blindness and brain damage. The case fatality rate was 4%. The extent of a head injury was not always clinically apparent at the initial presentation and should be promptly defined by computed tomographic scan. Despite the recent ban on the sale of lawn darts, there remain an estimated 10 to 15 million sets of lawn darts in the homes of Americans. Pediatricians should encourage parents to discard all lawn darts.

Adolescent↗
PubMed1990

Nifedipine and isosorbide dinitrate alone and in combination for patients with chronic stable angina: a double-blind crossover study.

Since not all patients tolerate beta-blockers, the efficacy of nifedipine and isosorbide dinitrate was evaluated alone and in combination in patients with stable angina pectoris. The study was a randomized double-blind crossover design with patients titrated to maximally tolerated doses of both drugs. Phases included isosorbide dinitrate alone, nifedipine alone, and isosorbide dinitrate plus nifedipine in combination, with efficacy determined by stress testing. Eleven men and one woman patient with a mean age of 60 years and a mean of five anginal episodes/week completed the study. Patients were in New York Heart Association (NYHA) classes I, II, and III. With nifedipine alone compared with isosorbide dinitrate alone, patients had fewer angina attacks/week (p less than 0.02), exercised longer before experiencing angina (p less than 0.03), and had less ST segment depression during (p less than 0.03) or after (p less than 0.05) exercise. When patients received isosorbide dinitrate plus nifedipine, only time to onset of angina during exercise (p less than 0.05) was significantly different from the response with isosorbide dinitrate alone. Analysis of variance between nifedipine and isosorbide dinitrate plus nifedipine was not significant. Diastolic blood pressure with isosorbide dinitrate plus nifedipine (p less than 0.04) was lower than with isosorbide dinitrate alone. No significant differences in systolic blood pressure were noted between the treatment groups. The drugs alone and in combination were relatively well tolerated. Nifedipine alone may be superior to isosorbide dinitrate alone. The combination of isosorbide dinitrate plus nifedipine demonstrated no advantage over nifedipine alone compared with isosorbide dinitrate alone.

Angina Pectoris↗
PubMed1990

Internal cardioverter defibrillator: component failure.

Sudden death occurred in a patient with congestive cardiomyopathy, sustained ventricular tachycardia refractory to amiodarone, and an automatic internal cardioverter defibrillator. Interrogation of the AICD at the time of death was indicative of malfunction. Postmortem analysis documented component failure involving a voltage regulating transistor resulting in prolonged charge times.

Cardiomyopathy, Dilated↗