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Biomedical subjects

F Dorey

Publications and source records attributed to F Dorey.

At least 73 records · Page 4Linked to original sources
PubMed1990

Significance of histological prognostic indicators in patients with carcinoma of the prostate.

The relationship between histological prognostic indicators and their relative significance in prognosis were studied in 139 patients who underwent radical prostatectomy. The estimated progression rates at 5 and 8 years were 14 and 52% respectively for patients with high grade tumours, 25 and 50% for those with capsular penetration, 31 and 58% for patients with seminal vesicle invasion and 23 and 55% for those with lymph node metastases. Each of the 4 parameters yielded an approximately equal increased risk of disease progression at 5 and 8 years. The occurrence of 2 or more risk factors in the same patient did not result in a statistically increased risk of progression at 5 and 8 years. The effect of capsular involvement on progression was directly related to the extent of invasion. The progression rate at 8 years was 3% for patients with mild involvement, 19% for those with extensive invasion and 50% for those with capsular penetration.

Adult↗
PubMed1990

Stem fracture incidence in Trapezoidal-28 stainless steel hip arthroplasty.

From 1970 to March 1978, 716 forged stainless steel Trapezoidal-28 (T-28) total hip arthroplasties were performed at the authors' institution with a follow-up period from one to 15 years (mean, 64 months). There were 13 (1.8%) stem fractures and one (0.1%) neck fracture. Average time to fracture was 95 months. All fractures occurred in stems implanted before 1976, using early femoral acrylic stem fixation techniques. Stem fracture was related to time of surgery, stem size, patient height, patient weight (for males), and patient age. Survivorship analysis predicted an overall ten-year fracture rate of 4%, and a ten-year rate of 5% for T-28 stems implanted before 1976. There have been no reported fractures in the 204 T-28 stainless steel prostheses implanted since 1976. The mean patient follow-up period for the T-28 stems implanted after 1975 was 52 months, and only 16 patients have been followed for nine years or more. Thus, a longer patient follow-up period is needed in the post-1975 group in order to determine the long-term fracture rate in this group. However, the major difference between this group and the early group is the use of an improved cementation technique, as well as the use of larger prostheses when possible. There was no material or manufacturing change until the introduction of the TR-28 prostheses in 1978.

Adolescent↗
PubMed1989

[Primary hyperaldosteronism caused by unilateral macronodular hyperplasia].

A case or primary hyperaldosteronism due to unilateral macronodular adrenal hyperplasia is presented. This entity is exceptional: a review of the literature has yielded only three similar cases. The significance of these adrenal nodules is discussed; in particular, they are compared with the nodules found in hypertensive subjects. Their course after surgery is similar to that of Conn's adenoma.

Adrenal Gland Diseases↗
PubMed1989

Effects of vasoactive intestinal polypeptide, TRH, and dopamine on prolactin secretion in estrogen-primed postmenopausal women.

Prolactin secretion is influenced by at least three important hypothalamic neurotransmitters: TRH, vasoactive intestinal polypeptide and dopamine. The purpose of this study was to determine whether, in estradiol-primed postmenopausal women, the PRL response to TRH, vasoactive intestinal polypeptide, and dopamine differed. Ten postmenopausal women were studied during treatment with estradiol benzoate at a dose of 0.625 mg per day during 15 days. TRH (200 micrograms iv), saline infusion, vasoactive intestinal polypeptide (75 micrograms infused iv during 15 min), coadministration of vasoactive intestinal polypeptide and TRH, and dopamine (4 micrograms.kg-1.min-1 iv for 3 h) were administered for 5 consecutive days before and during the last 5 days of estradiol benzoate treatment. Before estradiol benzoate administration, the PRL, response to TRH was significantly greater than that of vasoactive intestinal polypeptide. Estradiol benzoate treatment increased significantly the PRL release induced by TRH (p less than 0.01), but did not modify the response to vasoactive intestinal polypeptide. At the end of estradiol benzoate treatment, the maximal increase in PRL after the combined (vasoactive intestinal polypeptide + TRH) test was greater than that obtained with TRH alone and occurred earlier (p less than 0.04). Dopamine suppressed PRL secretion to a similar extent after estradiol benzoate treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Dopamine↗
PubMed1989

The validity of survivorship analysis in total joint arthroplasty.

The use of survivorship analysis requires an assumption that patients who are lost to follow-up are no more or less likely to be at risk of failure of an operation or a procedure than are patients who are still being followed. This is a major assumption in long-term orthopaedic studies, in which a high percentage of patients are usually lost to follow-up. We compared the survivorship curve for the first 100 Tharies replacements done at our institution (which were completed by September 1977), using data that were collected in the standard way up to 1985, through a letter requesting a follow-up visit, with the curve for the same patients that was based on almost complete follow-up data that were gathered by telephone from 1985 on. The similarity of the two curves suggested that the assumptions that are necessary for the validity of survivorship analysis are reasonable, even in the orthopaedic setting, in which many patients are lost to follow-up. The usefulness of the survivorship curve for prediction was also evaluated by comparing the curve based on the first forty-six of the 100 Tharies replacements (before 1977) with the curve based on the last fifty-four such operations (from January 1977 to September 1977). The results of these two comparisons suggest that survivorship analysis is a valid technique to use in the long-term evaluation of patients who have had a joint replacement.

Adult↗
PubMed1989

Warfarin prophylaxis to prevent mortality from pulmonary embolism after total hip replacement.

Between 1970 and 1987, 3000 total hip replacements were performed at the University of California at Los Angeles, and all patients were given warfarin prophylactically, in conjunction with early postoperative elevation of the lower limb in balanced suspension and the application of elastic hose. Since 1973, the first dose of warfarin has been given on the night of the operation, and the prothrombin time has been maintained between sixteen and eighteen seconds. A pulmonary embolism occurred after fourteen (0.5 per cent) of the 3000 operations. It was never fatal. Bleeding occurred after forty-four operations (1.5 per cent). The effectiveness of the protocol of the University of California at Los Angeles was demonstrated in a large number of patients over a seventeen-year period. Since 1974, the protocol has included closer monitoring of the prothrombin time. After 2595 hip replacements that were done between 1974 and 1987, the rate of pulmonary embolism was 0.2 per cent and the rate of bleeding complications was 1.0 per cent. However, recently a higher incidence of bleeding complications (2.3 per cent) has been noted after non-cemented total hip (stem-type) replacement.

Drug Evaluation↗
PubMed1988

Porous surface replacement of the hip with chamfered-cylinder component.

One hundred porous surface replacements (PSR) were performed in 92 patients (63 men and 29 women) with a mean age of 53 (range 17-76). Follow-up times range from 1 to 4 years, with 48 patients having a follow-up of at least 2 years. Preoperative diagnoses were osteoarthritis (OA) 63, osteonecrosis (ON) 13, dysplasia 9, rheumatoid-ankylosing spondylitis 6, and other 9. Seventeen hips had metal-backed acrylic-fixed THARIES acetabular sockets, nine hips had a porous cobalt chrome hemispheric beaded acetabular component with adjuvant fixation screws and externally protruding screw hubs, and 74 hips had a porous chamfered cylinder-design acetabulum. Pain relief had been immediate and more complete than with acrylic-fixed or biologic-ingrowth stem-type replacement with comparable walking and function improvements. There have been no major systemic complications, sepsis, or loosening. There have been two transient peroneal nerve palsies and three trochanteric fibrous unions. There have been three reoperations, one for subluxation, one for "metalosis" due to mesh pad loosening, and one femoral neck fracture. Examination of one removed femoral surface component which has been histologically sectioned revealed excellent (90%) bone in-growth. Circumferential progressive radiolucencies developed at the bone-cement interface by 1 year in all of the 17 acrylic-fixed acetabular components. Reaming or seating defects were noted in 25% of the ingrowth components on postoperative radiographs. Radiographic analysis of immediate postoperative films of the chamfered cylinder design acetabular components frequently demonstrated bone-component interface radiolucencies which represented component seating defects. These initial interface radiolucencies became progressively more narrow over the first six months postoperatively suggesting "healing" of the reamed bone-component interface with trabecular bone around the chamfered cylinder acetabular components. Partial healing of initial interface voids with residual narrow radiolucencies were typical of the nine hemispheric-design acetabula with adjuvant screws and screw hubs. This new porous surface replacement (PSR) of the hip using porous ingrowth fixation avoids the major disadvantages of acrylic-fixed SR: excessive acetabular reaming and difficulty with acetabular revision. (When conversion to stem-type replacement is necessary the modular polyethylene socket liner can be exchanged.) The PSR has the prospect of enhanced fixation and improved longterm durability.

Alloys↗
PubMed1988

Relationship of DNA content to conventional prognostic factors in clinically localised carcinoma of the prostate.

One hundred and nine patients treated by total prostatectomy for apparently localised carcinoma were analysed to investigate the prognostic significance of capsular invasion and penetration, seminal vesicle invasion, lymph node metastases, grade as assessed by the Gleason and MD Anderson Hospital (MDAH) systems and DNA content measured by flow cytometry of nuclear material extracted from paraffin embedded tumour. Comparison of DNA content was made with 36 benign prostates. Mean follow-up/survival was 60.7 months, at which time 21 patients had evidence of recurrence or had died. Only 5 patients had local recurrence. Tumour grade, as assessed by both the Gleason Sum Score and the MDAH system, correlated with anatomical extent and was the most important determinant of time to recurrence. Fifty-nine tumours were diploid, 44 tetraploid and 6 aneuploid. One of 36 benign prostates showed aneuploidy. Ploidy did not correlate with the anatomical extent of the tumour or with grade. Tetraploid tumours recurred earlier than diploid tumours. None of 6 aneuploid tumours have recurred, although only 3 have been followed beyond 5 years. Multivariate analysis showed that after accounting for grade, none of the other variables, including ploidy, contributed any additional significant prognostic information. Although the results must be regarded as preliminary, in view of the small number of patients with recurrence, they suggest that DNA content offers limited prognostic information in clinically localised prostate cancer.

Aged↗
PubMed1988

Reconstruction of the anterior cruciate ligament using a torn meniscus.

In eighty of 100 patients, reconstruction of the anterior cruciate ligament using a torn meniscus was successful in restoring stability. The length of follow-up ranged from two to six years and the mean interval from injury to operation was two years. Preoperatively, all but one patient had a positive (2+ or 3+) Lachman test and a positive pivot-shift test. Only ten patients had evidence of major instability, as seen on either test. The result was the same regardless of whether the patient had had a concomitant extra-articular (Ellison) procedure. The results of arthroscopic biopsy in eleven patients did not support the hypothesis that the meniscus underwent metaplasia to ligamentous tissue. Although this procedure yielded results similar to those of other procedures in which autogenous tissues are used to reconstruct the ligament, the meniscus should rarely, if ever, be used for reconstruction of the anterior cruciate ligament. The procedure is indicated only for patients who, in addition to needing reconstruction of the anterior cruciate ligament, also have a torn meniscus that would otherwise have to be totally excised.

Adolescent↗
PubMed1987

Porous surface replacement of the hip with chamfer cylinder design.

Fifty-seven porous surface replacements (PSR) were performed in 53 patients (36 men and 17 women) with a mean age of 54 years (range, 19-75 years). Follow-up examination times ranged from one year to 2.5 years with 33 patients having follow-up periods of at least two years. Preoperative diagnoses were osteoarthritis (OA), 37; osteonecrosis (ON), six; dysplasia, nine; rheumatoid ankylosing spondylitis, three; and other, two. Sixteen hips had metal-backed acrylic-fixed THARIES (total hip articular replacement by internal eccentric shells) acetabular sockets, nine hips had a cobalt chrome hemispherical beaded acetabular component with adjuvant screws, and 32 hips had a chamfer-cylinder designed acetabulum. Pain relief has been immediate and more complete than with acrylic-fixed or biologic-in-growth stem-type replacements with comparable walking and function improvements. There have been no major systemic complications, sepsis, or loosening. There have been two transient peroneal nerve palsies and three trochanteric fibrous unions. There has been one subluxation requiring reoperation. Histologic sections of the removed femoral surface component showed excellent (90%) bone ingrowth. Circumferential progressive radiolucencies developed at the bone-cement interface by one year in all of the 16 acrylic-fixed acetabular components. Reaming or seating defects were noted in 25% of the patients on postoperative radiographs. Serial radiographic analyses demonstrate progressive narrowing of all of the chamfered cylinder design and less in hemispherical design with screw fixation. These observations are encouraging and suggest healing of the bone-component interface with bony trabeculae in the porous-coated acetabular design. This new surface replacement (SR) of the hip uses porous-ingrowth fixation to overcome the major disadvantages of acrylic-fixed SR which are as follows: (1) excessive acetabular reaming, (2) poor long-term fixation, and (3) difficulty with acetabular revision.

Adult↗
PubMed1987

Treatment of the anterior cruciate ligament-absent knee with associated meniscal tears. Instrumented testing and clinical evaluation of two patient groups.

The UCLA instrumented clinical testing apparatus was used to measure postoperative stiffness and laxity for two groups of patients with documented chronic absence of the anterior cruciate ligament (ACL) and associated meniscal tears. Group 1 consisted of 76 patients (average age, 25 years) who had undergone anterior cruciate substitution using the torn meniscus, and a second group of 34 patients (average age, 31 years) who had partial meniscectomy alone without ACL substitution. Subjective and objective evaluations were significantly higher and symptoms of pain and buckling significantly lower in the substitution group. In addition, 29% of Group 1 and only 7% of Group 2 patients were able to return to their preinjury sports without limitations, while 5% of the former and 12% of the latter could not return to any sport. At 90 degrees of flexion, there were no significant differences in stiffness or laxity between the patient groups. At 20 degrees of flexion and neutral foot rotation, the meniscal substitution group had an average of 1.4 mm less side-to-side laxity difference than the partial meniscectomy patients; 51% of the substituted patients still had an injured knee laxity that was at least 2 mm greater than the uninjured knee, as contrasted to 67% of the partial meniscectomy patients who exceeded this upper limit of the normal range. At 20 degrees, anterior stiffness of the injured knees of the substitution patients was 28% greater than the injured knees of the partial meniscectomy group; 42% of the substituted patients had an injured knee stiffness within the normal range, while only 18% of the partial meniscectomy patients fell within normal limits. There were no statistical correlations of stiffness or laxity values with clinical scores or patient symptomatology in either group.

Adult↗
PubMed1987

Survivorship comparison of THARIES and conventional hip arthroplasty in patients younger than 40 years old.

Early and high failure rates for conventional hip replacements in young and active patients are well documented. The hypothesis tested in this study is total hip articular replacement by internal eccentric shells (THARIES) resurfacing hip arthroplasty is a sufficiently durable alternative to conventional total hips in patients younger than 40 years old. Survivorship analysis techniques were applied to 106 THARIES and 98 conventional hip replacements. The primary outcome variable investigated was time to failure, as measured by the need for revision of the prosthesis in the absence of sepsis. Other definitions of prosthesis failure were also investigated. Analysis revealed that even within this young, high-risk population there were subpopulations with different risks for failure. The lowest risk patients comprised all rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) patients, regardless of age. The intermediate risk patients comprised all non-RA, non-JRA patients older than 30 years of age and the highest-risk patients were all non-RA, non-JRA patients younger than 30 years of age. A comparison of THARIES and conventional prostheses within each of these three subpopulations revealed similar patterns of failure over time, with the conventional total hip replacement having significantly better hip function than the THARIES group only in the highest-risk population, when using a failure definition of revision surgery for aseptic loosening. A broader and more important conclusion was that all acrylic-fixed implants, THARIES or THRs are predicted to undergo early mechanical loosenings in younger-than-30, non-RA, non-JRA patients. In patients younger than 30 years age acrylic fixation of THA is inadvisable.

Adult↗
PubMed1986

Pulmonary responses to exercise in pregnancy.

The pulmonary responses of 88 pregnant women were compared to those of 39 nonpregnant control subjects during different exercise intensities. At rest the pregnant women had higher tidal volumes, oxygen consumption, carbon dioxide production, and respiratory exchange ratio. With increased work loads the pregnant volunteers have consistently lagged behind the nonpregnant control subjects for every parameter, which indicates a decrease in pulmonary reserve and inability to exercise anaerobically.

Adult↗
PubMed1986

Survivorship analysis in the evaluation of joint replacement.

A major problem in the evaluation of patients receiving joint replacements is the lack of complete information on all patients. That is, at the time of analysis patients will not have been followed long enough to know what their status will be at the time point of interest (5 years, for example). The statistical technique of survivorship analysis is the appropriate method for evaluating this type of data. The authors illustrate the technique of survivorship analysis as it applies to total joint arthroplasty, using examples from the UCLA total hip arthroplasty data base. In addition, the benefits of using this technique over the usual "failure rate" analysis are discussed, as well as other issues concerning the analysis of joint replacement data.

Follow-Up Studies↗
PubMed1986

THARIES resurfacing arthroplasty. Evolution and long-term results.

The unsatisfactory results of total hip arthroplasty in the young patient led to the development of the concept of hip resurfacing. Total hip articular replacement by internal eccentric shells (THARIES) resurfacing was introduced in 1975, with the primary goal of bone stock preservation and the hope of increased durability in the young patient. Major changes in design and technique include thicker and more uniform acrylic layers, metal-backed flanged acetabular component, and reduction in femoral size for preservation of acetabular bone stock. Of the 584 hips (average patient age, 48 years) with one- to ten-year follow-up study, there have been 72 failures (revision rate, 12.3%) with 66 cases of loosening (nearly all beginning in or limited to the acetabular side), two neck fractures, and four sepses. Survivorship analysis revealed that the single most important factor related to prosthesis failure is age followed by diagnosis and experience of the surgeon. Osteoarthritis and rheumatoid arthritis were favorable categories with congenital dysplastic hip (CDH), osteonecrosis, and previous failed resurfacing being unfavorable categories. Experience has taught the importance in preserving acetabular bone stock, providing bone graft for socket coverage in severe dysplasia, and removing dead bone in osteonecrosis. While resurfacing did not solve the problems of the young patient, even those patients who failed often gained time for application of the newer techniques and materials. The femoral component infrequently failed. The head remained vascular. This leads the authors to conclude that the surface arthroplasty concept is a viable alternative to total hip arthroplasty and seems to be ideal for the application of porous technology.

Adult↗
PubMed1986

The effects of pressurization on fracture swelling and joint stiffness in the rabbit hind limb.

Long bone fractures frequently cause limb swelling and joint stiffness, and the two effects are generally assumed to be related, an assumption long held but rarely tested. The authors investigated limb swelling and joint stiffness in rabbits with experimental 28-day healing fractures. Eleven control rabbits were treated with bilateral hind limb skeletal fixation and unilateral distal tibia fractures. Subsequent limb swelling occurred bilaterally, but it was significantly greater on the side fractured. All fractures healed. Ankles in both fractured and unfractured limbs became significantly stiffer, compared with preinjury values, but ankles in the fractured limbs became significantly stiffer than those in the unfractured control limbs. Air pressure of 10 mmHg above atmospheric pressure was applied for four days to newly fractured limbs in 11 additional rabbits. Pressurization reduced swelling but did not significantly affect ankle stiffness. In general, reduction in postfracture swelling by application of external pressure did not significantly affect adjacent joint stiffness.

Animals↗
PubMed1986

The UCLA Charnley experience: a long-term follow-up study using survival analysis.

During the period between February 1970 and December 1973, 149 Charnley total hip arthroplasties were performed at UCLA Medical Center. Fifty-seven percent have a follow-up period of at least four years, and 21% have a follow-up period of ten years or more. The peri- and postoperative complication rate was high, with an incidence of 32.6% urinary tract infection (UTI), 4% peroneal nerve palsy, 4% cardiopulmonary, 2% pulmonary embolism, 1.3% myocardial infarction, and 6.0% other. Eleven patients (7.3%) required revision at a mean of 75 months after operation, while an additional three patients were experiencing substantial pain. Clinical improvement after this procedure is similar to that reported by other authors. Survivorship analysis suggests that being young and/or having a diagnosis of osteonecrosis or failed hemiarthroplasty places a patient at a higher risk of failure due to revision surgery or pain.

Adult↗