Search PubMed⌕ Search

Biomedical subjects

J R Nelson

Publications and source records attributed to J R Nelson.

At least 37 records · Page 2Linked to original sources
PubMed1993

Bilateral and unilateral gamete intrafallopian transfer (GIFT) are not equivalent therapies if unilateral GIFT is chosen to avoid one abnormal tube.

PURPOSE: The relative effectiveness of bilateral and unilateral gamete intrafallopian transfer (GIFT) was compared. Bilateral GIFT, where possible, was the preferred method of transfer and occurred in 328 patients. One hundred sixty-seven patients undergoing unilateral GIFT were placed into one of seven categories based on the indication for unilateral GIFT. Three categories included patients with either historical or laparoscopic evidence of unilateral tubal abnormalities, two categories included patients without tubal disease, and two categories contained patients in whom the physician could not choose between unilateral or bilateral GIFT. RESULTS: Results demonstrate that unilateral GIFT in patients with either historical or laparoscopic evidence of unilateral tubal disease had significantly lower pregnancy and implantation rates than patients undergoing bilateral GIFT or those undergoing unilateral GIFT without evidence of tubal disease (P < 0.01). CONCLUSION: The presence of unilateral tubal abnormalities predicts a lower likelihood of pregnancy in patients undergoing unilateral GIFT through the tube presumed to be normal.

Adult↗
PubMed1993

Permeability of latex and thermoplastic elastomer gloves to the bacteriophage phi X174.

BACKGROUND: Most studies challenging the integrity of the glove barrier have compared the permeability of vinyl and latex gloves. However, no studies of a new nonlatex, nonvinyl thermoplastic elastomer have been reported. This pilot study therefore compared the protective barriers provided by latex and thermoplastic elastomer surgical gloves against penetration of the bacteriophage phi X174. METHODS: Twenty thermoplastic elastomer gloves and 25 commercially available latex gloves (20 brand 1, 5 brand 2) were filled with a sterile serum surrogate and exposed to the phi X174 virus in a flask, with shaking for 180 minutes at 37 degrees C. Aliquots of 5 ml were withdrawn at baseline, 30, 60, 120, and 180 minutes and assayed by a standard plaque assay. The remaining contents of the gloves were then tested by an extremely sensitive qualitative assay (plaque assay without dilution of the sample). RESULTS: With the standard plaque assay, virus was detected in 30% of the brand 1 latex gloves, in 80% of the brand 2 latex gloves, but in none of the thermoplastic elastomer gloves. The qualitative assay, which can detect even a single virus in the entire glove contents, had positive results for 30% of the thermoplastic elastomer gloves, 70% of the brand 1 gloves, and 100% of the brand 2 gloves. CONCLUSIONS: Despite the small sample, the results of this stringent assay suggest that the mechanical barrier offered by thermoplastic elastomer gloves is equal to or better than that provided by the latex gloves tested. Clinical studies are needed to evaluate thermoplastic elastomer gloves, which may withstand mechanical stress better than latex or vinyl. Thermoplastic elastomer gloves may therefore be a desirable alternative for health care workers in high-risk settings or for individuals with latex allergies.

Bacteriophages↗
PubMed1993

Long-term management of adenomyosis with a gonadotropin-releasing hormone agonist: a case report.

Leuprolide acetate was used to produce a constant hypoestrogenic environment in a young patient with histologically confirmed adenomyosis. Conservative medical therapy was initiated because of the patient's complaint of severe dysmenorrhea coupled with her strong desire for uterine conservation. The initial daily subcutaneous dose was eventually converted to monthly intramuscular depot formulation for patient convenience. A dramatic therapeutic response was observed with each course of therapy. This included a marked reduction in uterine size, amenorrhea, and complete resolution of pelvic pain. Cyclic use of an OC agent following LA was associated with a return of symptoms and uterine growth. The patient did, in fact, conceive immediately on cessation of analogue therapy.

Adult↗
PubMed1993

Predicting success of gamete intrafallopian transfer.

OBJECTIVES: To examine seminal parameters predictive for success in a cycle of GIFT and to construct an algorithm using pertinent seminal data as well as easily obtained historical data to predict pregnancy and viable pregnancy rates. DESIGN: A retrospective study of 544 cycles in 376 couples. SETTING: A private IVF-ET and GIFT center. PATIENTS: Couples in a GIFT program with a mean of 53.6 months of infertility who had failed to conceive with other therapies. INTERVENTIONS: Gamete intrafallopian transfer. MAIN OUTCOME MEASURES: Pregnancy as a function of laboratory historical data with emphasis on seminal parameters. RESULTS: Motility was the only seminal parameter that was predictive. Success was correlated with the number of oocytes returned and inversely related to female age. An algorithm to predict pregnancy in a GIFT cycle as well as viable pregnancy was constructed. CONCLUSIONS: Motility is the only seminal parameter predictive for success in a GIFT cycle. An easily programmable algorithm can be constructed to help patient and physician decide on the appropriateness of GIFT for each couple.

Adult↗
PubMed1992

Leuprolide acetate-prepared in vitro fertilization-gamete intrafallopian transfer cycles: efficacy versus controls and cost analysis.

OBJECTIVE: To evaluate the effect of gonadotropin-releasing hormone agonist (GnRH-a) when given through stimulation with gonadotropins versus stopping it as stimulation was initiated versus a control group unprepared in this manner. Also, to construct a cost analysis for this type of therapy in an in vitro fertilization-gamete intrafallopian transfer program (IVF-GIFT). DESIGN: Prospective, consecutive, randomized, with a control group. SETTING: An out-patient IVF-GIFT program. PATIENTS: One hundred new patients entering an IVF-GIFT program. INTERVENTIONS: In vitro fertilization or GIFT cycles with or without preparation (pituitary suppression) by GnRH-a administration in which suppression was continued or halted as gonadotropins were begun. MAIN OUTCOME MEASURES: Cancellation rates, ampules, and days of gonadotropin use, costs, estradiol (E2) level, egg numbers and quality, and pregnancy rates. RESULTS: Stopping GnRH-a (leuprolide acetate) therapy as stimulation was begun did not lessen the suppressive effect in reduction of spontaneous luteinizing hormone surge as seen with continued use of agonist. In contrast, the control group had a 30.3% cancellation rate before ovum retrieval. The E2 and egg data among the groups were similar, but as expected, agonist use led to the need for more and longer duration of gonadotropin stimulation. Pregnancy rates were not different by group. Costs were approximately even by the third initiated cycle.

Adult↗
PubMed1992

Magnetic resonance imaging in carotid dissection.

Magnetic Resonance Imaging was performed in two cases of suspected internal carotid artery dissection. In both cases it was possible to demonstrate the dissection. It is suggested that magnetic resonance imaging (MRI) could replace more invasive techniques in the diagnosis of this condition.

Adult↗
PubMed1992

Oxygenation and ventilation during cardiopulmonary resuscitation utilizing continuous oxygen delivery via a modified pharyngeal-tracheal lumened airway.

Use of continuous transtracheal oxygen delivery systems combined with rhythmic chest compressions can provide excellent oxygenation and ventilation during cardiopulmonary resuscitation. However, occasional displacement of the transtracheal catheter results in life-threatening pneumomediastinal complications. We investigated using the pharyngeal lumen of a pharyngeal-tracheal lumened airway (PtL) as an alternative delivery system for continuous oxygen flow in 21 large mongrel dogs. Excellent ventilation was possible in anesthetized, apneic, and paralyzed dogs in normal sinus rhythm from the "bellows" effect of chest compressions. The hypercapnia and respiratory acidemia resulting from 5 min of complete apnea in ten dogs during normal sinus rhythm was readily corrected (p less than 0.01). In an additional 11 dogs, external chest compressions were performed and oxygen was delivered continuously via the PtL during 20 min of ventricular fibrillation. During this period of cardiac arrest, pH declined (7.38 +/- 0.01 vs 7.19 +/- 0.02; p less than 0.01), but PaCO2 (35 +/- 1 vs 38 +/- 3 mm Hg) and PaO2 (67 +/- 2 vs 68 +/- 3 mm Hg) were not significantly different from prearrest values. Successful resuscitation was achieved in 8 of 11 (73 percent) animals, which is similar to the results in historical controls with endotracheal intubation. No pneumomediastinal complications were seen with use of the PtL. We conclude that using the pharyngeal lumen of the PtL for continuous delivery of oxygen combined with external chest compressions can provide a safe and effective mode of oxygenation and ventilation during cardiac arrest.

Animals↗
PubMed1991

Anti-ischemic effects of atenolol versus nifedipine in patients with coronary artery disease and ambulatory silent ischemia.

The anti-ischemic effects of atenolol and nifedipine were compared in a randomized double-blind crossover manner in 24 patients with stable exertional angina and transient silent ischemia during ambulatory electrocardiographic (ECG) monitoring. Both atenolol and nifedipine were effective (p less than 0.005) in reducing the average number and duration of transient ischemic events, but therapy with atenolol was associated with a significantly greater reduction in the mean number (p less than 0.05) and duration (p less than 0.01) of silent ischemic events. Analyses of the silent ischemic activity during the morning hours revealed that only therapy with atenolol produced a significant reduction in the average duration per patient (139 +/- 54 vs. 1,609 +/- 468 s, p less than 0.01) and in the average duration of silent ischemia per event between 6 AM and 12 noon (62 +/- 21 vs. 208 +/- 24 s, p less than 0.005). There were fewer adverse experiences during therapy with atenolol. These results show that although both atenolol and nifedipine are effective in reducing silent ischemic events, treatment with atenolol is associated with significantly greater efficacy, particularly on the morning surge of silent myocardial ischemia.

Angina Pectoris↗
PubMed1991

Limitations of open-chest cardiac massage after prolonged, untreated cardiac arrest in dogs.

STUDY OBJECTIVES: Open-chest cardiac massage is an effective method of resuscitation if instituted within 15 minutes of normothermic cardiac arrest that has failed to respond to ongoing closed-chest CPR efforts. The usefulness of invasive forms of CPR after various periods of untreated cardiac arrest is less certain. This study was performed to determine the effectiveness of open-chest resuscitation after prolonged periods of untreated cardiac arrest. SETTING AND DESIGN: Prospective, controlled laboratory investigation using an animal model of cardiac arrest. Open-chest cardiac massage initially was compared to standard closed-chest compression CPR. The efficacy of open-chest CPR then was evaluated after ten and 40 minutes of untreated ventricular fibrillation. TYPE OF PARTICIPANTS: Twenty mongrel dogs (24 +/- 1 kg). MEASUREMENTS AND MAIN RESULTS: After 20 minutes of untreated ventricular fibrillation, open-chest resuscitation was significantly better than closed-chest efforts for the production of coronary perfusion pressure (58 +/- 14 vs 2 +/- 1 mm Hg; P less than .05) and initial resuscitation success (five of five vs one of five; P less than .03). Open-chest cardiac massage was equally effective for initial resuscitation if begun after ten or 20 minutes of untreated ventricular fibrillation (five of five vs five of five), but if untreated ventricular fibrillation continued for 40 minutes prior to instituting open-chest massage, no resuscitation benefit was found (none of five; P less than .005). There were marked differences in 24-hour survival depending on the length of time untreated cardiac arrest continued prior to instituting open-chest resuscitation efforts. After 20 minutes of ventricular fibrillation, initial resuscitation was successful with open-chest massage, but long-term survival was poor. CONCLUSION: Open-chest cardiac massage did not produce long-term survival if untreated cardiac arrest persisted for 20 or more minutes prior to invasive resuscitation efforts.

Animals↗
PubMed1991

Comparative time estimation skills of Hispanic children.

76 Hispanic and 47 Caucasian children from an urban school district located in a racially mixed neighborhood were compared on their ability to make functional time estimates. The findings indicate that initial differences in ability to make time estimations dissipate across Grades 1 to 5.

Child↗
PubMed1991

Proteus syndrome in 7 patients: clinical and genetic considerations.

The Proteus syndrome is a congenital hamartomatous disorder delineated in 1983. Because of its polymorphic appearance, the syndrome was named after the greek god Proteus whose name means much less than the polymorphous much greater than. Major clinical findings include hemi hypertrophy, macrodactyly, exostoses, scoliosis, epidermal nevi, haemangiomas, deeply rugated soles of the feet and a variety of deep and subcutaneous masses. We report on 7 new cases of Proteus syndrome. All reported cases have been sporadic. Therefore this syndrome could be due to the action of a dominant lethal gene surviving by mosaicism.

Adult↗
PubMed1990

A probable sex difference in mutation rates in ornithine transcarbamylase deficiency.

Ornithine transcarbamylase deficiency is an X-linked disease with possible manifestations in heterozygous females. Using segregation analysis in families from the literature pooled with a French series, the penetrance could be estimated to be 17% in heterozygous females (15% with severe and 2% with milder symptoms). Using these estimates, the proportion of sporadic cases among heterozygous females and hemizygous males could be derived. This proportion is 57% in females. In males, it depends on mutation rate values: assuming equal mutation rates in sperm and eggs, this proportion should be 40%. However, this value can be strongly rejected based on the proportion of isolated cases in male sibships. In both sets of data, segregation analysis provided no evidence for sporadic affected males, suggesting that there are virtually no mutations in eggs. The upper limit of the confidence interval, 0%-16%, can be taken as the maximum prior probability that an affected male occurs as the result of a new mutation in his mother's germ cells.

Female↗
PubMed1990

The moral reasoning of juvenile delinquents: a meta-analysis.

To test the hypothesized immaturity of juvenile delinquents' moral reasoning, the results of 15 studies of the moral reasoning of juvenile delinquents were integrated quantitatively using meta-analysis. Hedges and Olkin (1985) methods were used to (a) compute effect sizes, (b) test the homogeneity of the obtained effect sizes, and (c) test the statistical significance of the pooled mean effect size. The results supported the hypothesis that the moral reasoning of juvenile delinquents is immature. It was concluded that several other issues are in need of investigation.

Adolescent↗
PubMed1990

The role of religions in the analysis of the ethical issues of human gene therapy.

Beginning with critical writings of certain theological ethicists in 1965, religious bodies increasingly have been fostering studies of emerging issues implied by genetic technology. While perceiving this new science as consistent with belief in God as Creator, they define a number of dangers to human well-being and natural environment that might result from abuse of knowledge. The way in which religious concerns and their spokesman have now entered into discussions within the scientific community is of notable importance.

Ethics, Medical↗
PubMed1990

Evaluation of the anti-influenza virus activities of 1,3,4-thiadiazol-2-ylcyanamide (LY217896) and its sodium salt.

1,3,4-Thiadiazol-2-ylcyanamide (LY217896) and its sodium salt were shown to be effective against influenza A and B viruses in vitro and in the mouse model. In nondividing confluent MDCK cells, the 50% inhibitory concentration of LY217896 ranged from 0.37 to 1.19 micrograms/ml against various strains of influenza A virus and from 0.75 to 1.54 micrograms/ml against various strains of influenza B virus, with no apparent cytotoxicity. However, at a concentration of 0.31 microgram/ml, LY217896 inhibited the replication of dividing MDCK cells. LY217896 (9 mg/m2 of body surface area per day) administered in the diet, in the drinking water, by oral gavage, by intraperitoneal injection, or by aerosolization was well tolerated and protected CD-1 mice infected with a lethal dose of influenza A or B virus. Effective administration of the compound could be delayed for up to 96 h postinfection. Virus titer was reduced by 1 to 2 log10 units in lungs of mice given LY217896 in the drinking water. Mice treated initially with protective levels of LY217896 were resistant to a subsequent challenge of influenza virus in the absence of the compound, indicating that the animals were able to develop immunity to the initial infection. Administration of LY217896 to uninfected mice did not induce interferon-like activity or interfere with natural killer cell function. In the ferret, LY217896 was effective in preventing fever induced by influenza virus.

Animals↗
PubMed1990

Pathophysiology of silent myocardial ischemia during daily life. Hemodynamic evaluation by simultaneous electrocardiographic and blood pressure monitoring.

The role of myocardial oxygen demand in the genesis of silent myocardial ischemia was evaluated by measuring the heart rate and blood pressure changes preceding the silent ischemic events during daily life in 25 men with proven coronary artery disease. Simultaneous 24-48-hour ambulatory electrocardiographic and blood pressure monitoring were performed during unrestricted daily activities. Of the 92 transient ischemic events recorded during monitoring, 85 (92%) were silent. Sixty-one percent of the silent events were preceded by an increase in the heart rate of 5 beats/min or more. Seventy-three percent of the silent ischemic events showed an average increase of 10 mm Hg in systolic blood pressure within 6 minutes preceding the onset of ST segment depression. The silent ischemic events showed a circadian pattern with a high density (34% of total events) between 6:00 AM and noon. The increase in heart rate and blood pressure paralleled the increase in silent ischemic events during these hours. These results showing significant (p less than 0.001 for both) increases in heart rate and blood pressure preceding a majority of silent ischemic events suggest that increase in myocardial oxygen demand plays a significant role in the genesis of silent ischemia. This pathophysiological mechanism has important therapeutic implications.

Activities of Daily Living↗
PubMed1990

Faculty willingness to accommodate students with learning disabilities: a comparison among academic divisions.

One hundred seven faculty members at a northwestern college responded to a questionnaire devised to assess faculty willingness to provide students with learning disabilities instructional, assignment, examination, and special assistance accommodations. Faculty responses to the questionnaire were analyzed to determine if differences existed among faculty in the colleges of Education, Business, and Arts and Sciences. Results indicate that, in general, faculty were willing to provide students with learning disabilities accommodations, but that differences exist among the three academic divisions as to faculty willingness to provide students accommodations. The implications of these results for colleges and universities and future research are discussed.

Achievement↗