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Biomedical subjects

J Boyle

Publications and source records attributed to J Boyle.

At least 37 records · Page 2Linked to original sources
PubMed1996

Coronary artery disease in insulin-dependent diabetes mellitus of pregnancy (class H): a review of the literature.

Coronary heart disease and myocardial infarction are uncommon complications during pregnancy. Women with insulin-dependent diabetes mellitus (IDDM) have a much greater risk of serious coronary heart disease, but few cases of myocardial infarctions occurring during pregnancy have been reported. Significant maternal morbidity has been reported in half of these cases. This is a case of a myocardial infarction occurring at 21 weeks of gestation in a patient with class R/F IDDM and the subsequent pregnancy management as well as a review of the literature concerning Class H IDDM in pregnancy.

Adult↗
PubMed1996

Randomized, controlled phase I/II, trial of combination therapy with delavirdine (U-90152S) and conventional nucleosides in human immunodeficiency virus type 1-infected patients.

Delavirdine mesylate (DLV) is a potent nonnucleoside reverse transcriptase inhibitor with activity specific for human immunodeficiency virus type 1. In the present phase I/II study we evaluated the safety, toxicity, pharmacokinetics, and antiretroviral activities of two-drug and three-drug combinations of DLV and conventional doses of nucleoside analogs compared with those of both DLV monotherapy and two-drug nucleoside analog therapy. A total of 85 human immunodeficiency virus type 1 infected patients with CD4 counts of 100 to 300 cells per mm3 were enrolled in two periods: in the first period patients were randomized to receive either zidovudine (ZDV) plus didanosine (group 1) or ZDV plus didanosine plus escalating doses (400 to 1,200 mg/day) of DLV (group 2). In the second period, patients were randomized to receive either 1,200 mg of DLV alone per day (group 3) or ZDV plus 1,200 mg of DLV per day (group 4). DLV demonstrated good oral bioavailability at all five doses tested. The major toxicity was a transient mild rash which appeared in 44% of all DLV recipients. Overall, group 2 patients demonstrated more sustained improvements in CD4 counts, percent CD4 cells, branched DNA levels, p24 antigen levels, and virus titers in plasma than group 1, 3, or 4 patients. The magnitude of the response correlated with the intensity of prior nucleoside analog treatment, the non-syncytium-inducing or syncytium-inducing viral phenotype at baseline, and the presence of a wild-type codon at amino acid position 215 in the baseline reverse transcriptase genotype. Despite a transient rash, DLV therapy was well tolerated. Combination therapy with DLV and nucleoside analogs appears promising, with the three-drug combination appearing to be more potent that either two-drug combinations or monotherapy.

Adult↗
PubMed1995

Characterization of proteoglycan accumulation during formation of cartilagenous tissue in vitro.

In order to study proteoglycan retention and accumulation, we optimized a chondrocyte cell culture system in which isolated bovine articular chondrocytes accumulate extracellular matrix to form a continuous layer of cartilagenous tissue. The tissue can attain a thickness of up to 110 microns by 35 days. The cells synthesize large keratan sulfate containing proteoglycans and type II collagen indicating that the chondrocytes maintain their phenotype in these culture conditions. Matrix accumulation is enhanced by increased cell density and the presence of serum and ascorbic acid. The amount of proteoglycans synthesized by the chondrocytes increases up to day 21 and then decreases to the same levels as are synthesized during the first week of culture. The percentage of newly synthesized proteoglycans retained in the matrix increases from 20% on day 6 to a maximum of 85% by day 35. The proteoglycan and collagen content in the tissue increases with time in culture. The changes in the percentage of proteoglycans retained parallels the increase in proteoglycan content. After day 35, there is no further increase in the amount of proteoglycans and collagen nor in the percentage of newly synthesized proteoglycans retained in the extracellular matrix. These studies demonstrate that the cultures are going through two phases: one of matrix accumulation and then one of maintaining the existing matrix. The period of matrix accumulation occurs between days 10-21 whereas matrix maintenance is observed after day 35. Using this culture system to study proteoglycan accumulation and maintenance during these culture periods may prove useful in identifying the mechanisms regulating these processes.

Animals↗
PubMed1994

Cyclosporin enhancement of cisplatin chemotherapy in patients with refractory gynecologic cancer. A Gynecologic Oncology Group Study.

BACKGROUND: Cyclosporin has been demonstrated to reverse resistance to several antineoplastic agents including cisplatin in vitro. The purpose of this Phase I trial was to study the potential clinical application of cyclosporin modulation of cisplatin and to establish a tolerable dose of cyclosporin when combined with a standard dose of cisplatin of 75 mg/m2. METHODS: A course of therapy consisted of two cyclosporin infusions over 2 hours each, 24 hours apart, with cisplatin given 6 hours after the first dose. Treatment was repeated every 21 days. Cyclosporin was studied in a Phase I fashion at five different levels, from 1-5 mg/kg per dose. Twenty patients with refractory gynecologic cancer received 81 courses of therapy. All patients had received extensive prior chemotherapy containing cisplatin. RESULTS: Grade 4 nephrotoxicity was seen in 4 of 20 patients: 1 treated at 1 mg/kg, 1 at 2 mg/kg, and 2 at 5 mg/kg of cyclosporin. The patient treated at the 1 mg/kg level was a partial clinical responder and tolerated six courses. The patient at the 2 mg/kg level had received 14 prior courses of cisplatin and tolerated only two additional courses before a Grade 4 renal toxicity developed. Grade 4 nephrotoxicity developed in the two patients receiving 5 mg after two courses of chemotherapy. Two of the 20 patients achieved a complete response (CR) and 3 patients achieved a partial response (PR), for a total response rate of 25% (5 of 20). The two women who achieved CR started treatment with symptomatic ascites; one of whom also had multiple pulmonary lesions that were no longer evident after three courses of therapy. CONCLUSIONS: Cyclosporin at a dose of 4 mg/kg per day given for 2 consecutive days in association with 75 mg/m2 of cisplatin can be given with reasonable assurance of safety.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Radical moral disagreement in contemporary health care: a Roman Catholic perspective.

This paper addresses the moral challenges presented by the existence of radical moral disagreement in contemporary health care. I argue that there is no neutral moral perspective for understanding and resolving these challenges, but that they must be formulated and resolved from within the various perspectives that generate the disagreement. I then explore the natural law tradition's approach to these issues as a test case for my thesis.

Attitude↗
PubMed1994

Internal fixation or hemiarthroplasty for undisplaced fractures of the femoral neck in octogenarians.

We compared the reoperation rate after internal fixation for minimally displaced or impacted intracapsular fractures of the femoral neck in patients aged 80 years and above with that in similar patients aged 65 to 79 years. We also compared the results of internal fixation with those of hemiarthroplasty for displaced intracapsular fracture in an age- and sex-matched group of elderly patients. We found that a significantly greater proportion of the older patients treated by internal fixation required reoperation than either the younger group or the age-matched group treated by hemiarthroplasty. Our results indicate that internal fixation may not be the best treatment for extremely elderly patients with minimally displaced or impacted intracapsular fractures of the femoral neck.

Aged↗
PubMed1993

Molecular screening. Prospects for a new approach.

Tumors arise through a series of genetic steps that involve alterations of various cellular genes. The recent revolution in molecular genetic techniques has allowed direct identification of genetic changes within tumors. Because these changes are intimately involved in tumor progression, they are specific markers for cancer. A novel assay based on the polymerase chain reaction allows detection of a rare cancer cell containing a specific point mutation among an excess background of normal cells. This technique has allowed identification of p53 gene mutations in pathologic tissue samples from primary head and neck cancer. A small population of cancer cells has been detected in a variety of histologically negative clinical specimens, including saliva, surgical margins, lymph nodes, and chyle. The precise detection of these rare cancer cells in various clinical samples has significant implications for otolaryngology-head and neck surgery. This approach holds promise for screening of head and neck cancer and may call for the reassessment of current histopathologic staging through utilization of new molecular genetic techniques.

Genes, p53↗
PubMed1993

Multivariable model for prediction of risk of significant complication during diagnostic cardiac catheterization. The Registry Committee of the Society for Cardiac Angiography & Interventions.

Although adequate data exist on the frequency of procedural-related complications during diagnostic cardiac catheterization, little information is available for the quantitative assessment of risk factors for significant complication. We analyzed 58,332 procedures in the 1990 SCA&I Registry Database in order to assess 1) the independent and cumulative significance of easily obtainable pre-procedural factors predictive of major complication and 2) the likelihood of a significant complication given the presence of these risk factors. A model was developed on a random sample of 38,888 patients and validated in the remaining 19,444 patients. Twelve variables were identified as having independent predictive behavior for significant complication with excellent agreement in the validation sample. The current model is an accurate and reliable instrument for stratifying risk of a significant complication during diagnostic catheterization.

Aged↗
PubMed1993

Oncogene mutations as intermediate markers.

Tumors arise through a series of genetic changes which include activation of protoocogenes and inactivation of tumor suppressor genes. It is now possible to identify rare cells containing genetic mutations in an excess background of normal cells. Theoretically, the identification of a clonal population of cells sharing an early genetic marker for malignant transformation would lead to valuable intermediate endpoints and could diagnose premalignant lesions amenable to chemoprevention. Ideally, these genetic changes would be specific point mutations that occur early in the tumor cascade, prior to the development of a clinically significant tumor. To identify these markers, precise histopathologic and genetic tumor models must be described. Early candidate markers include p53 point mutations in squamous cell carcinoma of the aerodigestive tract.

Anticarcinogenic Agents↗
PubMed1993

Clinical experience with the micronucleus assay.

Because of the logistical and practical problems that make cancer prevention trials using cancer incidence as an endpoint virtually impossible to conduct for the majority of cancer types, there is a desperate need for valid intermediate markers of cancer risk to serve as surrogate endpoints in chemoprevention trials. A long and continually growing list of potential markers has been developed in the recent past. Unfortunately very few, if any, of them have been subjected to the usual quality control requirements for a laboratory test before being applied to clinical settings. Modulation of micronuclei frequency has been reported in a number of chemoprevention trials involving the oral cavity, esophagus, lung, and lower GI tract; however, we have focused our efforts primarily on applying the assay to exfoliated buccal mucosal cells, since much of the published data deal with this site, and oral cancer prevention is the theme of one of our chemoprevention trials. After standardizing the definition of a micronucleus by literature review and direct exchange of slides and photographs with other investigators active in the field, we obtained smears from normal subjects, smokers with or without leukoplakia, and tobacco chewers with or without leukoplakia. Our summarized findings follow: (1) Micronuclei represent only one of numerous cytological abnormalities in exfoliated buccal cells that are manifest particularly in tobacco chewers. These include a high frequency of anucleate, binucleate, and multinucleated cells, abnormal shapes and sizes of nuclei, etc.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticarcinogenic Agents↗
PubMed1993

Three cases of primary acquired melanosis of the conjunctiva as a manifestation of the atypical mole syndrome.

We report three patients with the atypical mole syndrome (AMS) [also known as dysplastic naevus or FAMMM syndrome] who presented with primary acquired melanosis (PAM). PAM is a melanocytic lesion of the conjunctiva which may progress to conjunctival melanoma. The association of this rare condition with the AMS phenotype in three individuals suggests that PAM may be a conjunctival manifestation of the AMS.

Adult↗
PubMed1992

Vascular smooth muscle cell detachment from elastin and migration through elastic laminae is promoted by chondroitin sulfate-induced "shedding" of the 67-kDa cell surface elastin binding protein.

Impaired elastin fiber assembly is observed in the fetal ductus arteriosus (DA), associated with a reduced concentration of elastin binding protein (EBP), a 67-kDa galactolectin. It is also seen in cultured aortic (Ao) smooth muscle cells (SMC) following the release of the EBP by glycosaminoglycans rich in N-acetylgalactosamine, such as chondroitin sulfate (CS). In the DA, impaired elastin fiber assembly is observed in conjunction with intimal thickening associated with increased migration of SMC into the subendothelium, a feature we previously related to increased production of fibronectin. In this report, we determined whether SMC use the EBP to attach to an elastin substrate, whether shedding of the EBP promotes SMC migration through a three-dimensional network of pure elastic laminae prepared from sheep aorta, and whether the latter is associated with increased production of fibronectin. We observed reduced attachment to elastin-coated surfaces of DA SMC deficient in EBP compared to Ao SMC. Addition of CS but not heparan sulfate (a glycosaminoglycan which does not induce EBP shedding) decreased Ao SMC attachment to elastin, as did preincubation with VGVAPG elastin-derived peptides which saturate the EBP. The immunolocalization of cell surface EBP suggested that cells can quickly replace EBP released from their surfaces by CS treatment. The magnitude of CS-induced impaired attachment of SMC to elastin was dose dependent and could be further increased by the administration of cyclohexamide and sodium azide. Also, the reversibility of CS-induced detachment was prevented by monensin. This suggests that a process of new synthesis and intracellular transport of the EBP was necessary to replace the EBP molecules released from the cell surface by CS treatment. In the migration assay, both DA and Ao SMC attached to the top of an elastin membrane, but only DA SMC deficient in EBP migrated through the laminae. Addition of CS, which induced shedding of EBP, resulted in Ao SMC migration associated with increased synthesis of fibronectin. We postulate that CS-induced release of EBP from SMC surfaces causes cell detachment from elastin and an increase in fibronectin synthesis, processes which may be critical in promoting SMC migration associated with intimal thickening developmentally in the DA and perhaps also in vascular disease.

Amino Acid Sequence↗
PubMed1992

Transforming growth factor-beta regulates increased ductus arteriosus endothelial glycosaminoglycan synthesis and a post-transcriptional mechanism controls increased smooth muscle fibronectin, features associated with intimal proliferation.

BACKGROUND: In previous studies we established that there are developmentally regulated increases in endothelial hyaluronan (HA) and heparan sulfate (HS), and smooth muscle cell fibronectin (FN) related to the formation of intimal cushions, structures essential to the postnatal closure of the ductus arteriosus (DA). In this report, we investigated the mechanisms underlying these features to ascertain whether they were independently or coordinately regulated. EXPERIMENTAL DESIGN: We determined by assessing HA polymer size and by pulse labeling with [3H]glucosamine whether the increased glycosaminoglycans (GAGs) incorporated in DA compared with aorta (Ao) endothelial cell matrices reflected increased synthesis of HA and HS rather than decreased degradation. We assessed whether transforming growth factor-beta (TGF-beta) may be responsible for the increased DA endothelial GAGs and smooth muscle FN production by confirming the presence of TGF-beta in DA tissue using immunohistochemistry and by assessing the effect of adding neutralizing antibodies to the cell cultures. We next determined whether the level of regulation of the increase in FN in DA smooth muscle cells was transcriptional or post-transcriptional by relating protein synthesis to steady state mRNA levels and to mRNA levels after serum stimulation. Using northern blot analyses with specific probes, we also explored the possibility that the FN produced by the DA and Ao was qualitatively different in the proportion of isoforms containing the V95+ region associated with secretion or the EIIIB+ region that has been related to migration. RESULTS: We observed that HA polymer size produced by DA and Ao endothelial cells was similar and we further verified using pulse labeling that the increase in DA compared with Ao endothelial GAGs reflected increased synthesis of HA and HS rather than decreased degradation. There was increased immunostaining for TGF-beta in DA compared with Ao tissue and we showed that TGF-beta neutralizing antibodies reduced synthesis of GAGs by the DA endothelial cells to the level of that seen in the Ao cells, but did not reduce DA smooth muscle cell FN synthesis. The increase in FN synthesis by DA compared to Ao smooth muscle cells was not associated with increased levels of steady-state mRNA for FN. Furthermore, following serum-stimulated increases in FN mRNA, the DA yielded greater amounts of FN protein compared to Ao smooth muscle cells. The increased FN production by the DA smooth muscle cells could not be attributed to a relative lack of degradation of FN protein or mRNA, or to qualitative differences which might influence secretion, as both cell types contained similar proportions of EIIIB+ and V95+ isoforms of FN. CONCLUSIONS: These results would suggest that, in contrast to the TGF-beta dependent increase in DA endothelial GAG synthesis, the increase in DA smooth muscle FN synthesis arises through differences in post-transcriptional regulation that are likely independent of TGF-beta.

Animals↗
PubMed1991

Who is entitled to double effect?

The doctrine of double effect continues to be an important tool in bioethical casuistry. Its role within the Catholic moral tradition continues, and there is considerable interest in it by contemporary moral philosophers. But problems of justification and correct application remain. I argue that if the traditional Catholic conviction that there are exceptionless norms prohibiting inflicting some kinds of harms on people is correct, then double effect is justified and necessary. The objection that double effect is superfluous is a rejection of that normative conviction, not a refutation of double effect itself. This justification suggests the correct way of applying double effect to controversial cases. But versions of double effect which dispense with the absolutism of the Catholic tradition lack justification and fall to the objection that double effect is an unnecessary complication.

Bioethical Issues↗
PubMed1991

Ventilatory control (Ventrol) simulation for education.

An educational microcomputer-based simulation of respiratory control has been developed. The program contains three major sections: tutorial, stimulation, and unknown testing. The tutorial section provides a brief discussion of the major factors involved in respiratory control. The simulation section provides a menu of variables to demonstrate the effects of altering inspired gases, changing compliance or airway resistance, metabolic acidosis, neural activity, and lesions (including vagotomy) or exercise. The last section of the program allows students to test their understanding of abnormal respiratory and blood gas values. The program has been used as a problem-solving exercise in a medical physiology course. Student groups were assigned to a microcomputer and given a specific problem during a regularly scheduled laboratory period. The students collected data using the program, analyzed and graphed or tabulated the results, and presented their findings in a minisymposium format to their fellow students. This approach has proven valuable and provides a number of pedagogical benefits that are lacking in a lecture-based basic science curriculum.

Computer Simulation↗
PubMed1991

Use of polymerase chain reaction to detect latent channel catfish virus.

Polymerase chain reaction was used to detect an economically important herpesvirus, channel catfish virus (CCV). A segment of the viral DNA was sequenced and oligonucleotide primers were produced from that sequence. After the primers were tested for the possibility of hybridization to catfish DNA, they were used to prime the polymerase chain reaction, using pure CCV DNA, CCV DNA added to catfish DNA, and DNA from catfish infected and not infected with CCV. In all cases, the method proved to be simple and sensitive in its detection by CCV DNA. When catfish DNA was present, less than 0.1 pg of CCV DNA was detectable. Channel catfish virus DNA in a latent carrier of CCV was readily detectable.

Animals↗