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Biomedical subjects

J J Collins

Publications and source records attributed to J J Collins.

At least 163 records · Page 9Linked to original sources
PubMed1991

Are sutures better than staples for closing bronchi and pulmonary vessels?

Little is known about the strength of suture lines and stapled closures of the bronchus, pulmonary arteries, and pulmonary veins. This experiment tested and compared the hydrostatic leakage point of each of these structures when closed by either sutures or staples. Fourteen fresh mature porcine cadavers and 8 human cadavers of age greater than 50 years were studied to determine whether the pig could be used as an appropriate model for future in vivo studies. Cadavers were selected so that closures depended only on the material used and not on any clot reinforcing the closure lines. The results of the study suggest that staple closure of the pulmonary artery and the main bronchus is as secure as suture closure. Pulmonary veins leak at a lower pressure when closed with staples; however, this pressure far exceeds physiological pressures in the left atrium. The data also suggest that the pig is an appropriate model for approximating conditions found in patients and is a good model for chronic studies comparing suture and staple closures.

Bronchi↗
PubMed1991

Concentration of cefuroxime in serum and middle ear effusion after single dose treatment with cefuroxime axetil.

Antimicrobial agents play an important role in the treatment of patients with acute otitis media and otitis media with effusion (OME). The study was undertaken to determine the concentrations of cefuroxime in the blood and middle ear effusions (MEE) of children between 6 and 12 years of age with acute otitis media and chronic OME after a single oral dose administration of cefuroxime axetil, the ester prodrug of cefuroxime. Cefuroxime axetil (250 mg) was administered 2 to 6 hours before either myringotomy for acute otitis media or myringotomy and tube insertion for chronic OME. Blood samples and middle ear aspirates were obtained from 31 children and the samples were analyzed by high performance liquid chromatography. Cefuroxime was recovered in measurable concentrations in all serum samples and in 15 (79%) of the 19 MEE specimens analyzed. No correlation was seen between cefuroxime MEE concentrations and effusion type, bacteriology or serum concentrations. This study shows that cefuroxime does penetrate into MEE when OME is present and that therapeutic concentrations can be achieved in some patients.

Acute Disease↗
PubMed1991

The long-term follow-up of the Hancock Modified Orifice porcine bioprosthetic valve.

The Hancock Modified Orifice valve is a specially fabricated, trileaflet porcine valve, which has been in clinical use at the Brigham and Women's Hospital since 1976. Three hundred seventy-nine aortic valve replacements with this device were implanted from 1976 to 1985; 305 were isolated aortic valve replacements and 74 were in association with a mitral valve bioprosthesis. The 305 patients undergoing isolated aortic valve replacement, a Food and Drug Administration patient group, are the subject of this article. The mean valve size was 22.5 mm, with 115 21-mm valves used. The mean functional preoperative class was 3.2; 99 of 305 patients (32.5%) underwent concomitant coronary artery bypass grafting. There were six operative deaths (2%). Patients were followed from 6-14 years (mean 7.4 years), and analysis was completed in early 1991. The 10-year actuarial calculation of survival freedom from reoperation, thromboembolism, structural valve degeneration, perivalvular leak, infectious valve degeneration, and total morbidity and mortality are presented.

Actuarial Analysis↗
PubMed1991

Pharmacokinetics of cefuroxime axetil and cefaclor: relationship of concentrations in serum to MICs for common respiratory pathogens.

The pharmacokinetics of single doses of cefaclor at 250 and 375 mg and cefuroxime axetil at 250 mg administered under optimal conditions (i.e., cefuroxime axetil after food and cefaclor in the fasted state) were studied in 24 healthy male volunteers. Drug concentrations in serum were related to MICs for common respiratory tract pathogens by using data generated from a recently completed national survey. The time the concentrations in serum exceeded the MICs for Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella (formerly Branhamella) catarrhalis were significantly greater (P less than 0.05) for cefuroxime axetil at 250 mg than for cefaclor at 250 or 375 mg. With the recommended dosing regimens (cefuroxime axetil at 250 mg and cefaclor at 375 mg twice daily or cefaclor at 250 mg three times daily), cefuroxime concentrations exceed the MIC for 90% of the strains tested for a greater time period than cefaclor concentrations with either regimen. The reasons for this difference are (i) the greater potency and slower clearance of cefuroxime compared with those of cefaclor and (ii) the greater sensitivity of these pathogens to cefuroxime.

Administration, Oral↗
PubMed1991

Clinical comparison of cefuroxime axetil, cephalexin and cefadroxil in the treatment of patients with primary infections of the skin or skin structures.

This study was designed to compare the clinical and bacteriological efficacy of three oral cephalosporins, cefuroxime axetil, cephalexin and cefadroxil, in the treatment of patients with mild to moderate infections of the skin or skin structures. A total of 330 patients were enrolled at 10 centers and were randomly assigned to receive cefuroxime axetil 250 mg (n = 107), cephalexin 500 mg (n = 111) or cefadroxil 500 mg (n = 112), twice daily for 10 days. Patients were assessed for their clinical and bacteriological responses once during treatment (3-5 days) and twice after treatment (1-3 and 10-14 days). A total of 353 bacterial isolates were obtained: Staphylococcus aureus (41%), Staphylococcus epidermidis (33%) and Streptococcus pyogenes (5%). A satisfactory clinical outcome (cure or improvement) was achieved in 97% (89/92), 89% (80/90) and 94% (82/87) of the clinically evaluable patients treated with cefuroxime axetil, cephalexin or cefadroxil, respectively (p = 0.047, cefuroxime axetil vs. cephalexin). With respect to the eradication of the bacterial pathogens, a satisfactory outcome (cure or presumed cure) was obtained in 96% (69/72), 85% (60/71) and 93% (63/68) of bacteriologically evaluable patients treated with cefuroxime axetil, cephalexin and cefadroxil, respectively (p = 0.026, cefuroxime axetil vs. cephalexin). All three study drugs were well tolerated, with adverse events affecting the gastrointestinal system most commonly reported. There were no significant differences between treatment groups in the incidence of drug-related adverse events.

Adolescent↗
PubMed1991

Muscle-ligament interactions at the knee during walking.

A two-dimensional mathematical model of the knee is used with gait analysis to calculate muscle, cruciate ligament and tibio-femoral contact forces developed at the knee during normal level walking. Ten normal adult subjects--four females and six males--participated. The knee model is based upon a four-bar linkage comprising the femur, tibia and two cruciate ligaments. It takes account of the rolling and sliding of the femur on the tibia during flexion/extension and the changes in direction of the ligaments and muscle tendons. We considered forces transmitted by six elements: quadriceps, hamstrings, gastrocnemius, anterior and posterior cruciate ligaments, and tibio-femoral contact. The equations of mechanics can be used to determine the absolute values of only three of the knee forces simultaneously, so that twenty limiting solutions of three of the six forces were considered. A limiting solution was rejected if any of the three forces were negative, corresponding to compressive muscle or ligament forces, or tensile contact forces. These constraints always reduced and at times removed the redundancy of the knee structures. The high incidence of predicted single muscle activity, supported by electromyography, suggested that the ligaments play a significant role in load transmission during gait. The temporal patterns of muscle and ligament activity and ligament force magnitudes were sensitive to the choice of model parameters. The analysis showed that each of four possible minimum principles of muscle selection--minimal muscle force, muscle stress, ligament force and contact force--was unlikely to be valid throughout the walking cycle.

Adult↗
PubMed1991

A focus on common needs. CHA's physician-facility project looks at future directions in healthcare.

Physicians and administrators of healthcare facilities lack integrated planning and decision-making processes, trust and confidence in each other, and a professional sense of satisfaction. A focus on common needs and interests is necessary to get the relationship on the desired track in the future. In 1989 the board of directors of the Catholic Health Association (CHA) created a special study group to review and develop recommendations on the relationships between physicians and healthcare organizations. The study group has addressed issues causing stress in these relationships, future changes in healthcare delivery that could affect these relationships, support CHA might provide, and ways to promote emphasis of these relationships and related issues among CHA members. The study group decided that collaborative planning and decision making will be the keys to getting to the desired future. This integration must go beyond shared planning activities and involve some degree of shared economic risk. The study group's final report, to be disseminated in spring of 1992, will identify key issues that significantly affect the physician-facility relationship, include resource materials to assist local organizations in assessing that relationship, and recommend ways to change the relationship through education.

Catholicism↗
PubMed1991

Possible progress and unresolved conflicts resulting from guidelines on good epidemiologic practices.

In summary, producing guidelines also produces conflict. The purpose of this paper was to delineate some of the conflicts that result from, or are involved in, having a set of guidelines for good epidemiologic practices. The goal was to present briefly both sides of the conflicts without trying to resolve them. The hope is that others will cogently argue one side or the other of these conflicts and convince the community to resolve the conflict, or alternatively, perhaps that the current guideline is somewhere in the middle of the beliefs in the community and thus is correctly positioned.

Clinical Protocols↗
PubMed1991

A study of the hematologic effects of chronic low-level exposure to benzene.

A study of 200 persons working with benzene showed no differences in commonly measured hematologic outcomes when compared with 268 nonbenzene workers in the same plant. Exposures ranged from 0.01 ppm to a high of 1.40 ppm 8-hour time weighted average over a 10-year period. Several other factors (age, sex, race, and smoking), however, were associated with these outcomes, indicating the importance of considering confounding factors when comparing hematology results. Exposure to low levels of benzene does not appear to produce an increased level of abnormal hematology measures detectable in routine medical surveillance.

Adult↗
PubMed1991

Extrapleural pneumonectomy, chemotherapy, and radiotherapy in the treatment of diffuse malignant pleural mesothelioma.

Malignant pleural mesothelioma has been considered a uniformly fatal disease associated with a median survival of 4 to 18 months. Extrapleural pneumonectomy alone has proved disappointing in the treatment of this disease, as have chemotherapy and radiotherapy. From 1980 to 1990, 31 patients with pleural mesothelioma underwent multimodality therapy that included extrapleural pneumonectomy with resection of the pericardium and diaphragm. The age of the patients was 53.4 +/- 8.6 years; 26 were male. All patients had the pathologic diagnosis reviewed before treatment. At thoracotomy six patients had residual (unresectable) gross disease, and in 23 there was histologic evidence of disease at the resection margin. The perioperative morbidity and mortality rates were 19% and 6%, respectively. The mean length of hospital stay for the 29 patients who survived the operation was 10.9 +/- 3.5 days. Postoperatively 26 patients received cyclophosphamide, doxorubicin, and cis-platinum chemotherapy with or without radiotherapy. The survival rates were 70% at 1 year and 48% at 2 years. Trends toward improved survival in the patients with complete resections approached but did not reach statistical significance. These data suggest that this multimodality protocol can be administered with acceptable morbidity and mortality. Prospective trials are justified to further clarify the role of this approach.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

HLA histocompatibility affects cardiac transplant rejection and may provide one basis for organ allocation.

Prospective human lymphocyte antigen (HLA) typing is not performed for heart transplantation, and the relation between HLA matching and cardiac graft rejection is unclear. Recipient and donor HLA matching were analyzed retrospectively in 51 patients undergoing orthotopic cardiac transplantation. Immunosuppression was based on cyclosporine and prednisone. During the mean follow-up of 34 months (range, 16 to 63 months), the 46 operative survivors had an average of 3.95 rejection episodes (range, zero to 11 episodes). Twenty-one patients had steroid-resistant rejection requiring treatment with polyclonal or monoclonal antithymocyte globulin. Human lymphocyte antigen typing was available for 44 patients, and antigens were grouped in broad specificities. Patients with two or more HLA-A or HLA-B matches had a reduced number of rejection episodes (3/10 versus 19/34) and a lower incidence of steroid-resistant rejection (1/10 versus 18/34; p = 0.01). Inclusion of HLA-DR matches did not alter the findings. There was a strong correlation between the increased frequency of rejection and the incidence of steroid-resistant rejection (p less than 0.0001). Four of six late deaths occurred in patients with steroid-resistant rejection; four were due to acute rejection and two to graft atherosclerosis. Although not currently done, prospective HLA matching is feasible with present typing methods. Our results suggest a rationale for prospective histocompatibility testing in cardiac transplantation with allocation of donor hearts to patients with two or more HLA matches.

Adult↗
PubMed1990

Vein of Galen aneurysm presenting with recurrent aseptic meningitis and subsequent spontaneous thrombosis.

Clinical and laboratory findings are described in the case of a patient with a vein of Galen aneurysm who presented with recurrent aseptic meningitis for which no etiology could be identified. The patient subsequently developed thalamic and intraventricular hemorrhage associated with partial thrombosis of the dilated vein of Galen. Review of the literature revealed no previously reported association of these conditions. Recurrent cerebral venous thrombosis involving the fistula is hypothesized as the cause of repeated inflammatory reactions near the subarachnoid space. More extensive thrombosis may then have precipitated the hemorrhage.

Adult↗
PubMed1990

Decreased operative risk of surgical treatment of mitral regurgitation with or without coronary artery disease.

The consecutive 2 year experience with patients undergoing first-time surgery for mitral regurgitation with and without coronary artery disease was reviewed. From January 1988 to January 1990, 127 patients with pure mitral regurgitation undergoing first-time operation were surgically treated. No other valve lesion, no reoperation and no congenital defects were included. The mean patient age was 62 years with 26% of the patients greater than 70 years. Twenty-six percent of the entire group was in functional class IV. Seventy-five patients received mitral valve repair and 52 underwent mitral valve replacement with a St. Jude or Hancock valve. In patients undergoing mitral valve repair, there was a higher incidence of those greater than 70 years old and of coronary artery disease and in patients undergoing mitral valve replacement there was a higher incidence of functional class IV. The operative mortality rate was 2.3% (3 of 127 patients). No patient failed to be discontinued from cardiopulmonary bypass and all three deaths occurred after mitral valve replacement, with one from complications of chronic renal failure and dialysis. There was no significant difference in patients who either did or did not have a concomitant coronary artery bypass graft and there was no difference related to age or functional class. Postoperative complications occurred in five patients in the valve repair group, including recurrent mitral regurgitation in two necessitating reoperation, and in three patients in the valve replacement group. With newer operative and postoperative management techniques, especially preservation of the papillary muscle annular continuity, the risk of mitral valve surgery, particularly of valve repair, is considerably lower than in previous years.

Coronary Disease↗
PubMed1990

Relationship of mood disorders to violence.

Past research on the relationship between mood disorders and violent behavior has been inconsistent, sometimes finding a relationship between the two and sometimes finding no relationship. Any relationship is arguably complex, and this area of research would benefit from attempts to clarify the relationship. This paper addresses the issue of complexity by examining the relationship between specific mood disorder categories and symptoms and six conceptually different indicators of violent behavior. Relationships are analyzed in logistic regression models where demographic and problem drinking variables are included to control variation that may be accounted for by these factors. The study uses a sample of 1140 recently incarcerated male felons. Psychiatric disorder diagnoses are based on the Diagnostic Interview Schedule. There is evidence of a direct relationship between a lifetime diagnosis of dysthymia and an arrest or incarceration history for robbery as well as with multiple incidents of fighting since age 18. Recurrent depression was significantly associated with a robbery incarceration history. Depression symptoms (regardless of whether a disorder diagnosis was made) were associated with multiple incidents of fighting since age 18. Manic symptoms were inconsistently associated with "expressive" violence and a number of mood disorder/violence models showed no significant relationship between the two.

Adult↗
PubMed1990

Comparative in vitro and in vivo susceptibilities of the Lyme disease spirochete Borrelia burgdorferi to cefuroxime and other antimicrobial agents.

The in vitro and in vivo susceptibilities of the Lyme disease pathogen Borrelia burgdorferi to cefuroxime were compared with those of several other antibiotics commonly used to treat this disease. Cefuroxime demonstrated a higher MBC in vitro (1.0 microgram/ml) than ceftriaxone (0.08 microgram/ml) or erythromycin (0.32 microgram/ml), but the MBC was similar to that of amoxicillin (0.8 microgram/ml) and doxycycline (1.6 micrograms/ml). B. burgdorferi was considerably less susceptible to tetracycline (3.2 micrograms/ml) and penicillin G (6.4 micrograms/ml). Of the three other Borrelia species tested, two (Borrelia turicatae and Borrelia anserina) also demonstrated susceptibility to cefuroxime, while the third (Borrelia hermsii) was less susceptible. Results obtained with four antimicrobial agents in the in vivo hamster model parallel the antibiotic susceptibilities in the in vitro study. The three antibiotics with similar MBCs in vitro, i.e., cefuroxime, doxycycline, and amoxicillin, demonstrated comparable activities in preventing borreliosis in B. burgdorferi-challenged hamsters (50% curative doses = 28.6, 36.5 and 45.0 mg/kg, respectively). Penicillin G, which demonstrated the highest MBC in vitro, had very weak protective activity in the hamster model system. These results indicate that the in vitro and in vivo activities of cefuroxime against B. burgdorferi are comparable to those of several oral antibiotics currently being used in the treatment of early Lyme disease and suggest that the oral form of this cephalosporin may be an effective alternative therapy for this disease.

Animals↗
PubMed1990

The role of the quadriceps in controlling impulsive forces around heel strike.

The damaging effect of transient loads on joints has been observed in vitro and in vivo, and may be an aetiological factor in osteoarthrosis. The events around heel strike, when the velocity of the foot is brought rapidly to zero, may be a source of such loads in normal activity. By modifying the rate at which the limb descends to the ground, quadriceps action influences the magnitude of the heel strike transient. Experiments were carried out to analyse the occurrence of these transients, and a two-dimensional mathematical model of the knee joint and lower leg was used to calculate the forces developed at the knee in response to them. Paralysis of the quadriceps resulted in a large increase in the heel strike transient.

Biomechanical Phenomena↗