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Biomedical subjects

J M Sheehan

Publications and source records attributed to J M Sheehan.

At least 37 records · Page 2Linked to original sources
PubMed1987

A comparison of four treadmill protocols for determination of maximum oxygen uptake in 10- to 12-year-old boys.

Little information is available regarding the relative effectiveness of various treadmill exercise protocols in eliciting maximal oxygen consumption (VO2 max) values in children. In this study of 10- to 12-year-old boys, running protocols produced significantly higher VO2 max levels compared with walking, but there were no important differences in continuous, intermittent, and handrail-supported running schedules. The intermittent run protocols, however, prolonged the test duration. Studies examining VO2 max in children should utilize standard criteria for demonstrating peak oxygen intake. In this study criteria of VO2 plateau, peak heart rate over 198 and respiratory quotient exceeding 1.0 were satisfied most commonly with running protocols.

Child↗
PubMed1986

Bilateral central dislocation of the hip: a case report.

Bilateral central dislocation of the hip is a rare injury. Most of the cases reported in the literature were the result of electroconvulsive therapy, one case following an eclamptic fit, and another following hyponatremic convulsions. An additional case, resulting from a grand mal epileptic fit, is reported.

Aged↗
PubMed1986

Trochanteric osteotomy in Charnley low-friction arthroplasty of the hip.

The use of trochanteric osteotomy in lateral approach to the hip joint is a fundamental part of Charnley's low-friction arthroplasty. Its use allows adequate exposure and easy orientation of the hip. Reattachment using a single transverse and double vertical wires was evaluated in 500 consecutive hip arthroplasties. Of 500 patients, 466 (93.2%) showed complete bony union of their trochanteric osteotomy at three months. A further 20 (4%) patients united by 12 months, giving a union rate of 97.2%; 34 (6.8%) patients who showed incomplete or defective union at three months. There were five dislocations. Only one patient required removal of the wires, for bursitis. The patients with defective bony union had a relatively high rate of wire breakage at three months. Despite a 1.8% complete detachment and 1% fibrous union, the transtrochanteric approach allows easy access without fear of shaft fracture in very difficult cases, with surprisingly little ill effect or loss of function even in those failing to reunite.

Aged↗
PubMed1985

Bilateral hip and knee replacement for rheumatoid arthritis.

A series of 19 patients with severe rheumatoid arthritis had replacement of both hips and both knees. They are reviewed after a mean follow-up of 27 months. The preferred programme is to replace hips before knees. Pain was relieved in all the patients and function was improved in all but two. Severe rheumatoid disease and prolonged immobilisation before the operations were not contra-indications to a successful outcome, but the presence or the development of cervical myelopathy combined with gross upper limb deformity militated against a good result.

Adult↗
PubMed1984

The significance of asymptomatic bacteriuria in patients undergoing hip/knee arthroplasty.

The urinary tract has received a great deal of attention as a possible source of infection following arthroplasty. The incidence and significance of asymptomatic bacteriuria in patients admitted for arthroplasty is obscure. The occurrence of bacteriuria was therefore analyzed retrospectively in 299 patients admitted for hip/knee arthroplasty to determine its incidence and relation to the age of the patient and the result of the operation. There was a high incidence of bacteriuria in patients 65 years of age or older and an abnormally high incidence of asymptomatic bacteriuria in younger patients of both sexes who were to undergo hip/knee arthroplasty. However, there was no correlation between bacteriuria and surgical infection in these patients. Bacteriuria is common in patients admitted to the hospital for arthroplasty and should not be considered a cause for postponement of surgical treatment in the absence of other signs of cystitis or pyelonephritis.

Age Factors↗
PubMed1983

A technique of medial ligament repair of the knee with cancellous screws and spiked washers.

Twenty-five cases of proximal and distal tears and avulsions of the medial ligament of the knee were repaired under tension using cancellous screws and spiked washers with a mean follow-up period of 11.2 months. All knees were submitted to 15 Kp lateral stress in 20 degrees of flexion and radiographs in this position compared with those of the opposite knee. All patients were reassessed clinically and radiologically when stressed with the Telos apparatus. Radiographic instability was demonstrated in four cases. We conclude that cancellous screws and spiked washers, applied correctly, provide better fixation than other described methods and give a satisfactory repair of the torn ligament.

Adolescent↗
PubMed1983

Fusion of the cervical spine for instability.

The orthopedic and neurosurgical literature is neither clear nor consistent in describing an unstable cervical spine. In a series of 25 patients treated by arthrodesis of the cervical spine for instability, 12 had Gallie fusions at the atlantoaxial level. Eight of those fusions were performed for rheumatoid arthritis. In three patients persistent subluxation of the atlas on the axis occurred because the wires were not fully tightened in areas of poor-quality bone. Stable fixation with relief of symptoms was achieved in all patients who had fusions at the subaxial level. Several of these patients had had prolonged nonsurgical treatment. With rheumatoid bone of poor quality, the surgeon must be very careful to tighten the wires only enough to secure a stable reduction for treatment of subaxial cervical instability. Since stability achieved by healing of soft tissue is generally unreliable, prolonged periods of nonsurgical treatment are not justified for traumatic instability.

Arthritis, Rheumatoid↗
PubMed1983

An analysis of the causes of deep infection after hip and knee arthroplasties.

Infection is a dreaded complication of joint arthroplasty. Deep infection may arise by contamination during operation, by secondary contamination of a discharging hematoma during the post-operative phase, or by the hematogenous route. Sixteen suspected cases of early and late deep infection in 1500 primary hip and knee arthroplasties performed during a ten-year period are reviewed. The operations were all performed by one of the authors (J.M.S.) in a Charnley Howarth sterile-air enclosure. No prophylactic antibiotic therapy was used, and the minimum follow-up period in all patients was one year. Suspected causes of infection were noted in six patients: the infection was considered to be hematogenous in three and to result from hematomas in two, and in the sixth patient a suspected rheumatoid cyst may have been a Brodie's abscess. Ten patients had no apparent predisposing source of infection, and breach of sterility technique was the most likely cause of infection in this group. Only two patients have required revision surgery to date. Although hematogenous infection of joint arthroplasty is possible, early, intermediate, or late infections generally are introduced during surgery either from the air or by direct contamination.

Bacterial Infections↗
PubMed1982

Open reduction and percutaneous Kirschner wire fixation in complete disruption of the acromioclavicular joint.

Open reduction and percutaneous Kirschner wire fixation was carried out in 35 patients who had sustained recent Allman type 3 dislocations of the acromioclavicular joint. At follow up, failure to maintain reduction had occurred in two patients, both over 55 years. All younger patients had returned to former sporting activities. Complications encountered were infrequent. Cosmetic results were satisfactory.

Acromioclavicular Joint↗
PubMed1980

Plasma membrane mediated thymidine transport in AKR spleen cells.

In this paper we characterize the thymidine transport systems in nonadherent spleen cells from normal leukemic (AKR) mice and from AKR mice which have been stimulated in vivo with concanavalin A (Con A). We have shown that splenic lymphocytes from normal AKR mice transport thymidine (two kinetic components, Km values of 34 microM and 1.6 mM) whereas lymphoid cells from C57L/J and outbred (CD-1) mice do not. Following Con A stimulation of AKR mice, three components (Km values of 6 microM, 212 microM, and millimolar range) were observed. The current data should be compared with previously published results for splenocytes from Con A stimulated CD-1 mice. Although those cells transport thymidine with two kinetic components (Km values of 160 microM), they lacked the lowest Km system present in AKR splenocytes. Thymidine transport was also examined in lymphocytes from several AK x L recombinant inbred mouse strains derived from the cross AKR/J x C57L/J. Two strains which lacked MuLV did not show time-dependent thymidine translocation whereas two strains which possessed MuLV demonstrated time-dependent thymidine translocation. Moreover, cells from the congenic strain L.AKR-Akv-2, which carried the Akv-2 genome on a C57L background, also showed thymidine transport. Thus a unique ability to transport thymidine can be correlated with the presence of the murine leukemia virus genome.

Adenosine↗
PubMed1978

Arthroplasty of the knee.

Arthrodesis of the knee is a simple and safe operation that ensures stability and freedom from pain. But it is achieved at the expense of movement and occasionally of social acceptability. If arthroplasty is to be recommended, the advantages of arthrodesis must be retained, with the added bonus of a functional arc of movement.

Aged↗
PubMed1977

Membrane transport by murine lymphocytes. II. The appearance of thymidine transport in cells from concanavalin A-stimulated mice.

We have investigated membrane transport of thymidine and adenosine by bulk murine nonadherent spleen cells from animals treated with the lectin concanavalin A. Separation of cells from radioactive medium was achieved by means of the oil microfuge technique which permits incubation periods as short as 4 sec. We were able to distinguish between the membrane-linked function of transport and uptake which includes subsequent accumulation and metabolism of the transport solute. Previously we reported that cells derived from untreated mice could not be shown to translocate thymidine in a carrier-mediated fashion. In contrast, cells from concanavalin A-treated mice showed two membrane transport systems for thymidine, a high affinity system (Km = 160 micronM) and one with low affinity (Km = 4 mM). The transport of thymidine conformed to the usual criteria for membrane carrier-linked function: increased uptake with time, substrate saturability and chemical specificity. In contrast to thymidine uptake, the transport of adenosine by cells from lectin-treated mice was similar to that shown by cells from untreated animals. Thus a specific membrane-linked activity is altered differentially in the course of mitogen-effected lymphocyte stimulation. We have found that determination of DNA synthesis by the standard method gave values which were as much as 700% too high, since the counts obtained by direct precipitation with TCA of cells incubated with radio-labeled thymidine exceed the cell-associated radiolabel obtained by the rapid sampling technique. With lectin-stimulated cells, the discrepancy observed was up to three times greater. Hence the validity of the standard assay for blastogenesis must be viewed with caution.

Adenosine↗
PubMed1976

Membrane transport by murine lymphocytes. I. A rapid sampling technique as applied to the adenosine and thymidine systems.

We have developed a rapid sampling technique for animal cells in suspension for the purpose of measuring membrane transport in lymphocytes. The method involves rapid centrifugation of cells through a layer of silicone oil into perchloric acid after incubation periods as short as 4 s. Using this method we have described the uptake of thymidine and the uptake and transport systems of adenosine by murine bulk nonadherent spleen cells. The two uptake systems are markedly different. Adenosine was shown to be taken up by classical carrier-mediated diffusion, while thymidine was not. In addition we have explored the metabolism of the two nucleosides under the conditions we employed for measuring transport or uptake; Both nucleosides are phosphorylated extensively. We also investigated the uptake and metabolism of thymidine over a 2-h interval the standard time used to measure DNA synthesis in lymphocytes. Unless cells were separated from medium by centrifugation through oil before TCA addition, the TCA precipitable counts exceeded the total radioactive uptake. Hence the standard method for measuring thymidine utilization yields estimates under these conditions which can be as much as 100% too high.

Adenosine↗