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Biomedical subjects

R Gray

Publications and source records attributed to R Gray.

At least 253 records · Page 14Linked to original sources
PubMed1991

Venous and arterial thrombosis in patients who received adjuvant therapy for breast cancer.

The records of 2,673 patients randomized according to seven consecutive Eastern Cooperative Oncology Group (ECOG) studies of adjuvant therapy for breast cancer were reviewed for the occurrence of vascular complications. All protocols opened and closed between June 1977 and July 1987. The objectives of the present study were (1) to compare the frequency of vascular complications among patients who received adjuvant therapy for breast cancer with patients on observation, and (2) to estimate the contribution of chemotherapy and hormonal therapy to the occurrence of venous and arterial thrombi. The frequency of thrombosis, both venous and arterial combined, was 5.4% among patients who received adjuvant therapy and was 1.6% among patients on observation (P = .0002). Premenopausal patients who received chemotherapy and tamoxifen had significantly more venous complications than those who received chemotherapy without tamoxifen (2.8% v 0.8%, P = .03). Postmenopausal patients who received tamoxifen and chemotherapy had significantly more venous thrombi than those who received tamoxifen alone (8.0% v 2.3%, P = .03) or those who were observed (8.0% v 0.4%, P less than .0001). Premenopausal patients who received tamoxifen and chemotherapy had a 1.6% frequency of arterial thrombosis, significantly more than patients who received chemotherapy alone (1.6% v 0.0%, P = .004). The frequency of arterial thrombosis among postmenopausal patients was not significantly correlated with adjuvant therapy. In conclusion, patients who received adjuvant therapy for breast cancer had a 5.4% frequency of thromboembolic complications, significantly more than those who were observed. The combination of chemotherapy and tamoxifen was associated with more venous and arterial thromboembolic complications than chemotherapy alone in premenopausal patients and with more venous thrombi than tamoxifen alone among postmenopausal patients.

Aged↗
PubMed1991

Cost-efficient study designs for binary response data with Gaussian covariate measurement error.

When mismeasurement of the exposure variable is anticipated, epidemiologic cohort studies may be augmented to include a validation study, where a small sample of data relating the imperfect exposure measurement method to the better method is collected. Optimal study designs (i.e., least expensive subject to specified power constraints) are developed that give the overall sample size and proportion of the overall sample size allocated to the validation study. If better exposure measurements can be collected on a sample of subjects, an optimal design can be suggested that conforms to realistic budgetary constraints. The properties of three designs--those that include an internal validation study, those where the validated subsample is derived from subjects external to the primary investigation, and those that use the better method of exposure assessment on all subjects--are compared. The proportion of overall study resources allocated to the validation substudy increases with increasing sample disease frequency, decreasing unit cost of the superior exposure measurement relative to the imperfect one, increasing unit cost of outcome ascertainment, increasing distance between two alternative values of the relative risk between which the study is designed to discriminate, and increasing magnitude of hypothesized values. This proportion also depends in a nonlinear fashion on the severity of measurement error, and when the validation study is internal, measurement error reaches a point after which the optimal design is the smaller, fully validated one.

Cohort Studies↗
PubMed1991

How to avoid bias when comparing bone marrow transplantation with chemotherapy.

It is important to know whether the survival of patients receiving an allogeneic bone marrow transplant (BMT) is better than that of patients receiving "conventional" treatment and, if BMT is better, to know how much better. Unfortunately, this information is surprisingly difficult to obtain accurately. Most studies that have attempted to define the value of BMT have been subject to varying degrees of bias because of the problems of identifying a "conventional chemotherapy" control group with which the outcome of patients who have received BMTs can be compared. A common bias arises when disease-free survival of BMT patients is compared with that of all other remitters. Early failures are then automatically assigned to the chemotherapy group even if they have donors and so would have gone on to a BMT had they not relapsed or died. Since some patients receive BMTs many months (or even years) after achieving remission-when their prognosis is already much improved-the definition of "early failure" is problematic. Nevertheless, although it is very rarely used, an adequate statistical method does exist to overcome this problem. Careful analysis cannot, however, overcome the problem of selection bias: patients selected for BMT are likely to have better (or worse) prognosis than patients who are treated conventionally. The only really satisfactory way of assessing the value of BMT is to conduct randomised trials comparing BMT with no BMT - or with extra chemotherapy. Several such studies are currently being undertaken assessing the role of autologous BMT in AML.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Marrow Transplantation↗
PubMed1991

Indwelling angiographic catheters to facilitate placement of ureteric stents.

In 16 of 191 patients the initial attempt to place a double-pigtail internal ureteric stent by conventional methods was unsuccessful. These patients had cancers of the rectum (nine patients), bladder (two patients), vagina (one patient), cervix (one patient) or spermatic cord (one patient) or radiation strictures (two patients). When a guide wire could be advanced beyond the stricture, placement of a small angiographic catheter for 7 to 10 days allowed delayed placement of the stent in all but one case.

Aged↗
PubMed1991

Pneumothorax resulting from acupuncture.

The authors report two cases of pneumothorax secondary to lung puncture, which was caused by acupuncture needles. Radiologists should be alert to this possible cause of pneumothorax, particularly when needle fragments can be seen in radiographs of the soft tissues.

Acupuncture Analgesia↗
PubMed1991

End-to-end versus end-to-side proximal anastomosis in aortobifemoral bypass surgery: does it matter?

The proximal anastomosis is still a controversial issue in vascular surgery. To compare end-to-end (EE) and end-to-side (ES) proximal anastomoses, the authors undertook a prospective study with 3 years' follow-up involving 120 patients, all of whom had aortobifemoral bypass. Fifty-one (42.5%) patients received the EE and 69 (57.5%) the ES anastomosis. The indications for surgery were abdominal aortic aneurysm (EE 51%, ES 0%; p less than 0.05), claudication (EE 33.3%, ES 53.6%; p less than 0.05) and critical ischemia (EE 15.7%, ES 46.4%; p less than 0.05). Patients in the EE group were older (mean age: EE 66.1 +/- 2.8 years, ES 60.9 +/- 1.1 years; p less than 0.05) and had more ischemic heart disease (EE 39.2%, ES 27.5%; p less than 0.05). Postoperative mean increases in transcutaneous oximetry (EE 15.5 +/- 3.9 mm Hg, ES 12.6 +/- 2.3 mm Hg) and the ankle-brachial pressure index (EE 0.34 +/- 0.05, ES 0.30 +/- 0.03) were not significantly different in the two groups. The operative death rate was higher for the EE group (EE 11.8%, ES 1.4%; p less than 0.05). Early thrombosis occurred in six patients, two in the EE group and four in the ES group. Computed tomography, done 1 year postoperatively in 95 patients, revealed two small (less than 3 cm) distal anastomotic dilatations, one in each group. At 3 years, cumulative survival and patency were similar in both groups. The authors conclude that the two anastomotic groups had very similar short- and long-term results, except for the operative death rate which was higher in the EE group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Increased mortality of women in coronary artery bypass surgery: evidence for referral bias.

STUDY OBJECTIVE: To determine whether differences in referral reasons explain the higher operative mortality of women in coronary artery bypass surgery. DESIGN: Case series. SETTING: A tertiary care, private teaching hospital. PATIENTS: Consecutive patients who had isolated coronary artery bypass surgery between 1982 and 1987 (total, 2297; 79% male and 21% female). MEASUREMENTS AND MAIN RESULTS: The inhospital mortality rate was significantly higher for women than for men (4.6% compared with 2.6%; P = 0.036; 95% CI for difference in mortality, 0% to 4.0%). Women were older than men (mean, 68.2 and 64.0 years, respectively; P less than 0.001), and a higher percentage of women were referred with unstable angina (P = 0.007), postmyocardial infarction angina (P = 0.029), congestive heart failure (P less than 0.001), and New York Heart Association class IV symptoms (66% compared with 45%, P less than 0.001). More men were referred with a history of an abnormal exercise test (P less than 0.001), and patients referred because of a positive exercise test had a lower mortality (P less than 0.001). Using multivariate analysis, adjustment for the higher preoperative functional class of women and for age accounted for all of the difference in mortality between men and women (odds ratio, 1.04; CI, 0.60 to 1.79; P = 0.89). After correction for functional class alone, there continued to be no significant difference in mortality between men and women (P = 0.40). CONCLUSIONS: Differences in functional class and age account for the higher operative mortality of women in coronary bypass surgery. Women are referred for coronary bypass surgery later in the course of their disease than men, and later referral may increase their changes of operative death.

Adult↗
PubMed1990

Adjuvant chemohormonal therapy with cyclophosphamide, methotrexate, 5-fluorouracil, and prednisone (CMFP) or CMFP plus tamoxifen compared with CMF for premenopausal breast cancer patients. An Eastern Cooperative Oncology Group trial.

The current trial was designed to assess whether the addition of prednisone or prednisone + tamoxifen would enhance the therapeutic effectiveness of 1 year of adjuvant CMF therapy. Premenopausal women with ipsilateral axillary node-positive breast carcinoma and known estrogen receptor (ER) status were randomized to receive 1 year of postoperative treatment with 12 28-day cycles of cyclophosphamide, methotrexate, 5-fluorouracil (CMF), CMF plus prednisone (CMFP), or CMFP plus tamoxifen (CMFPT). There were 553 analyzed cases with 188 receiving CMF, 183 CMFP, and 182 CMFPT. The overall time to relapse (TTR) and survival comparisons between the regimens are not statistically different at a median follow-up time of 7.7 years. The major subgroups currently with a suggestive TTR difference are greater than 3N+ (CMFPT greater than CMF, P = 0.07) and estrogen receptor-negative (ER-) greater than 3N+ (CMFPT greater than CMF, P = 0.03). Patients receiving CMFPT appeared to have a superior survival to CMF in the ER- greater than 3N+ cohort (P = 0.02). The following patient characteristics were associated with a significantly longer TTR: decreasing nodal involvement or tumor size, positive ER status, age greater than or equal to 40 years, and decreasing obesity. The favorable effects of decreasing nodal involvement, positive ER status, age 40 years or greater, and decreasing obesity carried over to survival. Development of amenorrhea was also significantly associated with improved survival (P = 0.001). Toxicity was increased by the addition of prednisone to CMF and by the addition of tamoxifen to CMFP. Overall relapse patterns were similar among the three regimens. The results of the current trial do not currently suggest an overall therapeutic benefit for adding prednisone or only 1 year of tamoxifen to CMF adjuvant treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hand.

Clinical criteria for the classification of symptomatic idiopathic (primary) osteoarthritis (OA) of the hands were developed from data collected in a multicenter study. Patients with OA were compared with a group of patients who had hand symptoms from other causes, such as rheumatoid arthritis and the spondylarthropathies. Variables from the medical history, physical examination, laboratory tests, and radiographs were analyzed. All patients had pain, aching, or stiffness in the hands. Patients were classified as having clinical OA if on examination there was hard tissue enlargement involving at least 2 of 10 selected joints, swelling of fewer than 3 metacarpophalangeal joints, and hard tissue enlargement of at least 2 distal interphalangeal (DIP) joints. If the patient had fewer than 2 enlarged DIP joints, then deformity of at least 1 of the 10 selected joints was necessary in order to classify the symptoms as being due to OA. The 10 selected joints were the second and third DIP, the second and third proximal interphalangeal, and the trapeziometacarpal (base of the thumb) joints of both hands. Criteria derived using the "classification tree" method were 92% sensitive and 98% specific. The "traditional format" classification method required that at least 3 of these 4 criteria be present to classify a patient as having OA of the hand. The latter sensitivity was 94% and the specificity was 87%. Radiography was of less value than clinical examination in the classification of symptomatic OA of the hands.

Adult↗
PubMed1990

Do nurses or doctors have an increased risk of developing multiple sclerosis?

A cluster of multiple sclerosis (MS) patients has been reported in seven of 307 nurses in Key West, Florida. The MS death rates in British nurses and qualified medical practitioners were looked at and no increased mortality from multiple sclerosis was found. Neither was there an increase in mortality from motor neuron disease (amyotrophic lateral sclerosis), the control disease. Death rates from MS vary with social class, being highest in social class IIIN (skilled non-manual) and lowest in social class II (intermediate). These different rates may be due to MS causing health related occupational mobility. Allowance for the inter-class variability in MS death rates did not materially affect the conclusion that death from MS appears to be no more common than expected among nurses and doctors than in the general population. Possible explanations for the cluster of multiple sclerosis among nurses in Key West are discussed.

Adult↗
PubMed1990

Properties and distribution of single voltage-gated calcium channels in adult hippocampal neurons.

1. The properties of single voltage-gated calcium channels were investigated in acutely exposed CA3 and CA1 pyramidal neurons and granule cells of area dentata in the adult guinea pig hippocampal formation. 2. Guinea pig hippocampal slices were prepared in a conventional manner, then treated with proteolytic enzymes and gently shaken to expose the somata of the three cell types studied. Standard patch-clamp techniques were used to record current flow through calcium channels in cell-attached membrane patches with isotonic barium as the charge carrier. 3. Single-channel current amplitudes were measured at different membrane potentials. Single-channel current-voltage plots were constructed and single-channel slope conductances were found to fall into three classes. These were (approximately) 8, 14, and 25 pS, and were observed in all three cell types. 4. The three groups of channels differed from each other in voltage dependence of activation: from a holding potential of -80, the small-conductance channel began to activate at about -40 to -30 mV, the medium-conductance channel at about -20 mV, and the large-conductance channel at approximately 0 mV. 5. Ensemble averages of single-channel currents during voltage steps revealed differences in voltage-dependent inactivation. The small-conductance channel inactivated completely within approximately 50 ms during steps from -80 to -10 mV or more positive. Steps to less positive potentials resulted in less inactivation. The medium-conductance channel displayed variable inactivation during steps from -80 to 0 mV. Inactivation of this channel during a 160-ms step ranged from virtually zero to approximately 100%. The large-conductance channel displayed no significant inactivation during steps as long as 400 ms. 6. The large-conductance channel was strikingly affected by the dihydropyridine agonist Bay K8644 (0.5-2.0 microM), resulting in a high probability of channel opening, prolonged openings, and an apparent increase in the number of channels available for activation. The medium and small-conductance channels were not noticeably affected by the drug. 7. The large-conductance channel could be induced to open at very negative membrane potentials by holding the patch for several seconds at 20 or 30 mV and stepping to -30 or -40 mV. This process was enhanced by Bay K8644, resulting in prolonged openings at potentials as negative as -100 mV.(ABSTRACT TRUNCATED AT 400 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1990

Adjuvant trial of 12 cycles of CMFPT followed by observation or continuous tamoxifen versus four cycles of CMFPT in postmenopausal women with breast cancer: an Eastern Cooperative Oncology Group phase III study.

A prospectively controlled randomized trial to compare the adjuvant efficacy of 12 cycles of cyclophosphamide, methotrexate, fluorouracil, prednisone, and tamoxifen (CMFPT) followed by observation or a total of 5 years of continuous tamoxifen versus four cycles of CMFPT followed by observation in postmenopausal women with operable node-positive breast cancer was started by the Eastern Cooperative Oncology Group (ECOG) in 1982. In 1986 the study was modified to allow patients on CMFPT X 12 plus continuous tamoxifen to be rerandomized after completing 5 years of tamoxifen to either continue for life or to stop therapy. Patients were stratified for number of involved nodes and estrogen-receptor (ER) status and randomized to receive one of three treatments: CMFPT X 4, CMFPT X 12, or CMFPT X 12 plus continuous tamoxifen. Of 962 patients entered on the study, 803 were eligible. Life-threatening toxicity occurred in 75 and lethal toxicity in seven patients. Median follow-up is 4.1 years; 279 patients had recurrent disease. Time to relapse (TTR) is significantly longer for patients on CMFPT X 12 plus continuous tamoxifen than for CMFPT X 4 (P = .002), or CMFPT X 12 (P = 0.05). Differences between four or 12 cycles of CMFPT are not significant; relapse-free rates at 5 years are 61% for CMFPT X 12 plus continuous tamoxifen, 51% on CMFPT X 12, and 52% on CMFPT X 4. Treatment differences in overall survival are not significant. Hormone receptor status and number of involved nodes were found to be significant prognostic parameters.

Antineoplastic Combined Chemotherapy Protocols↗