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Biomedical subjects

R B Smith

Publications and source records attributed to R B Smith.

At least 109 records · Page 6Linked to original sources
PubMed1993

Acute tolerance to triazolam during continuous and step infusions: estimation of the effect offset rate constant.

Although acute tolerance to selected effects of many benzodiazepines is known to occur, acute tolerance to triazolam has not been documented even in studies that have included pharmacodynamic modeling. The purpose of this investigation was to determine whether acute tolerance to triazolam occurs in humans. Intravenous bolus doses of triazolam were used to individualize two subsequent intravenous infusions: one to achieve and maintain a constant triazolam concentration and one to achieve a series of incremental steady-state concentrations; a placebo treatment was also included. Ten healthy men completed the four single-dose treatments. Serial blood sampling and psychomotor and memory testing were done. In the constant infusion treatment, mean performance impairment was greatest at 1 h and then decreased rapidly despite maintenance of a mean triazolam concentration of 2.48 ng/ml for 9 h. Neither learning nor changes in free concentration account for the observations. Additionally, data from the step-infusion treatment indicate that the triazolam effect-concentration relationship after a single dose can be altered by rate of administration. Because tolerance develops, the administration of drug in small increments results in an increased effect at a lower concentration, with a blunted maximal response. Furthermore, our data suggest intersubject variability in the rate of development of acute tolerance. Patients who develop tolerance more slowly would experience a longer duration of effect. Further study regarding the rate of development of tolerance to specific effects and in different patient populations is warranted.

Adult↗
PubMed1993

Retroperitoneal hematoma following femoral arterial catheterization: a serious and often fatal complication.

Retroperitoneal hematoma (RPH) following cardiac catheterization is an infrequent (0.15% incidence) but morbid complication. During a 13-month study period, 11 patients with a significant RPH requiring operative intervention were identified. The mean transfusion requirement was 8.7 units, with two deaths as a consequence of their RPH. Adjunctive cardiac procedures included percutaneous transluminal coronary angioplasty (five), stent placement (one), and thrombolysis (two). Two patients had RPH following aortography. Suspicion of RPH was most frequently prompted by a falling hematocrit (73%), with hypovolemic shock (systolic blood pressure < 90) in 64%. Lower quadrant or flank pain occurred in four patients. Lower extremity pain occurred in five patients due to femoral nerve compression. Of six patients with a preoperative femoral nerve palsy, complete resolution occurred in four cases. RPH following femoral arterial puncture is a cause of significant morbidity, particularly in the anticoagulated patient. Postcatheterization anticoagulation and high arterial puncture were the principal risk factors (p < 0.001). Early recognition is essential and should be prompted by a falling hematocrit, lower abdominal pain, or neurological changes in the lower extremity. There should be a low threshold for performing abdominopelvic CT scans in such patients. Management of RPH must be individualized: 1) patients with neurological deficits in the ipsilateral extremity require urgent decompression of the hematoma, 2) anticoagulation should be stopped or minimized, 3) hematoma progression by serial CT necessitates surgical evacuation and repair of the arterial puncture site.

Aged↗
PubMed1992

The evaluation of a behavioural food and weight control programme for obese patients with noninsulin dependent diabetes.

We report here on the evaluation of a behaviour modification programme for food and weight control in noninsulin dependent diabetes mellitus (NIDDM). The results of this pilot study, involving a highly selected group of patients, showed that weight was reduced by an average of 4.5% over 11 weeks and that this difference was statistically significant. This average weight loss is in the range typically found for similar programmes. Glycosylated haemoglobin fell by 7.8% on average and serum total cholesterol fell by 3%, both statistically significant changes. Triglycerides fell by 17%, although this was not significant. The programme in its present form appears helpful in aiding motivated patients to make modest improvements in their blood sugars and lipids. However, we have identified a number of modifications and additions that could be made to improve it.

Adult↗
PubMed1992

Styles of psychological adjustment in diabetes: a focus on key psychometric issues and the ATT39.

While knowledge of the biomedical factors in diabetes has grown in a steady and systematic fashion over the past 60 years, attempts to define, measure, and understand the relevant psychological constructs have only begun recently. In particular, there is need for psychometrically sound tests to tap these dimensions. This study examined the psychometric characteristics of the ATT39, a promising measure of psychological adjustment to diabetes. The results, based on three patient samples and using the FACTOREP factor-matching procedure, suggested that the ATT39 has a large single factor only. This new subscale appears clinically to measure the integration of diabetes and its treatment into the lifestyle and personality of a patient with diabetes.

Adaptation, Psychological↗
PubMed1992

Adjuvant radiotherapy in patients post-radical prostatectomy with tumor extending through capsule or positive seminal vesicles.

Between 1976 and 1989, 115 patients at UCLA had radical retropubic prostatectomy for clinically localized prostate cancer with positive surgical margins, penetration of tumor into or through the capsule, or positive seminal vesicles. Twenty-four of those received adjuvant radiotherapy after having recovered from surgery. Complications of adjuvant treatment were uncommon and included urethral strictures in 3 patients and transient leg edema in 1. No patient in this group has had proved clinical disease progression though 6 have isolated detectable serum prostate-specific antigen (PSA) values. Clinical disease-free survival at five and seven years was 92 percent. If detectable PSA is also considered as evidence of tumor recurrence, the corresponding disease-free survival rates were 75 percent at five years and 54 percent at seven years. The 91 patients who received no postoperative radiotherapy had a clinical disease-free survival of 67 percent at five years and 56 percent at seven years. Disease-free survival drops to 43 percent and 24 percent, respectively, if detectable follow-up PSA is considered an indicator of disease progression. The comparisons of the survivorship curves in this retrospective study for the two treatment groups are statistically significant both for disease-free survival (p = 0.041), and disease-free survival with undetectable PSA (p = 0.043). Adjuvant radiotherapy has a beneficial effect after radical prostatectomy in patients with local tumor extension.

Aged↗
PubMed1992

Salvage radical prostatectomy after failure of curative radiotherapy for adenocarcinoma of prostate.

Radical prostatectomy with curative intent was performed in 13 patients with prostate cancer after local failure of radiotherapy. Of these patients, 2 underwent cystoprostatectomy for bladder neck involvement by the prostatic tumor. Local recurrence had been diagnosed twenty-one to one hundred sixty-eight months (mean 65.4 months) after completion of radiotherapy (6,000-7,000 cGy; mean 6,136 cGy). Three patients had radioactive implants. Rising prostate-specific antigen (PSA) was part of the indication for surgery in 5 patients. Complications included minor rectal injury (1 patient) and total incontinence (2/13 patients). Two patients had positive surgical margins and 6/13 patients had involvement of seminal vesicles, 2 of whom also had positive lymph nodes. The authors conclude that salvage prostatectomy is feasible after radiation failure. Transrectal ultrasound and careful monitoring of PSA after irradiation treatment may improve patient selection and minimize the risk of complications and incomplete excision.

Adenocarcinoma↗
PubMed1992

Nonoperative management of visceral aneurysms and pseudoaneurysms.

During the period from 1975 to 1991, 41 patients with 60 visceral artery aneurysms were treated at the Affiliated Hospitals of Emory University. The total included 13 patients in whom 16 aneurysms were treated primarily by transarterial embolization. There were seven hepatic artery aneurysms, three splenic artery aneurysms, three gastroduodenal artery aneurysms, two left gastric artery aneurysms, and one right gastroepiploic artery aneurysm. Average age of these patients was 50 years; there were eight males and five females. Seven patients presented with gastrointestinal bleeding, and two patients presented with abdominal pain. In four patients, the aneurysm was an incidental finding. Etiology of the true or false aneurysms consisted of pancreatitis in two patients, trauma in three patients, connective tissue disease in one, and was unknown in the remainder. Embolization was performed in seven cases with Gianturco coils and Gelfoam, with coils alone in four, with Gelfoam alone in four, and with detachable balloons in one instance. Complete occlusion was achieved initially in 13 cases. Recanalization occurred in two patients over a mean follow-up period of 8.6 months, requiring re-embolization in one patient, whereas the other patient was managed expectantly. In three cases, embolization was unsuccessful: two cases required surgical correction, and one case was managed expectantly. Only one complication was related to the embolization procedure, which was a common hepatic arterial dissection that proceeded to the formation of a false aneurysm. Embolization as the primary treatment modality for visceral artery aneurysms should be considered in patients with the following diagnoses: pseudoaneurysms associated with pancreatitis, intrahepatic aneurysms, most splenic artery aneurysms, and gastric, gastroduodenal, and gastroepiploic aneurysms. The procedure has a low risk and may obviate a difficult surgical procedure, but it does not preclude surgical intervention should the need arise.

Adolescent↗
PubMed1992

Extrarenal angiomyolipomas of the perinephric space.

We describe 2 cases of extrarenal angiomyolipoma of the perinephric space. All other cases of extrarenal angiomyolipoma of the retroperitoneum are reviewed and the clinical relevance of this unusual pathological entity is discussed.

Adult↗
PubMed1992

Prostate specific antigen levels after radical prostatectomy in patients with organ confined and locally extensive prostate cancer.

A total of 230 patients with localized prostate cancer underwent radical retropubic prostatectomy at UCLA (pathological stage T1-3 N0, M0). Classification into groups included 115 patients with organ confined disease (group 1), 82 with invasion into or through the capsule (group 2) and 33 with seminal vesicle involvement (group 3). Median followup was 48 months. The 10-year, cause-specific survival was 96%, 90% and 63%, and 5-year, clinical, disease-free survival was 91%, 79% and 58% for the 3 groups, respectively. Recent prostate specific antigen (PSA) levels were measured in most patients, even those operated upon many years ago. Of the patients 41 had detectable (0.4 ng./ml. or greater) PSA levels without any other clinical evidence of progression and 15 with clinical evidence of progression had PSA levels in the detectable range at the time of clinical progression. When isolated detectable PSA was also considered an indicator of progression the 5-year and 10-year, disease-free rates were 61% and 41%, respectively. These data show that radical prostatectomy performed in patients with even microscopic invasion into the capsule, positive margins and seminal vesicle involvement is associated with a higher clinical progression rate than organ confined disease. If isolated detectable PSA is also considered an indicator of recurrence the disease-free survival after radical prostatectomy might be less than indicated by previous studies. The relationship among survival, local tumor extension and PSA must be carefully examined.

Adult↗
PubMed1992

Alprazolam in end-stage renal disease. II. Pharmacodynamics.

The sensitivity to the psychomotor and memory effects of alprazolam was evaluated in 12 normal subjects and 12 dialysis patients (seven patients receiving hemodialysis and five patients receiving continuous ambulatory peritoneal dialysis). Subjects received a single oral dose of 0.5 mg alprazolam, 2 mg alprazolam, and placebo in a double-blind, placebo-controlled, balanced, three-way crossover study with a Latin square design. After administration of the test drug, blood was obtained for alprazolam concentration and protein-binding determinations, and psychomotor performance, memory, and sedation were assessed. The maximum psychomotor impairment corrected for free alprazolam concentration was 5.0%, 8.2%, and 10.1% per nanogram per milliliter in normal subjects, patients receiving hemodialysis, and patients receiving continuous ambulatory peritoneal dialysis, respectively (p less than 0.01), after administration of 2 mg alprazolam. Free alprazolam concentrations at which 50% of maximum effect is elicited for psychomotor impairment were 10, 7.40, and 5.31 ng/ml in normal subjects, patients receiving hemodialysis, and patients receiving continuous ambulatory peritoneal dialysis, respectively. The maximum memory impairment corrected for the maximum free alprazolam concentration was 4.4%, 7.2%, and 8.9% per nanogram per milliliter, respectively (p less than 0.09), after administration of 2 mg alprazolam. Thus our group of patients receiving dialysis showed enhanced sensitivity to some psychomotor and memory effects of alprazolam.

Adult↗
PubMed1992

Successful bone grafting of fracture nonunion at the forearm radial flap donor site.

A case of donor-site fracture following a radial forearm flap was treated conservatively with plaster but failed to unite. Successful union was achieved with bone grafting, external fixation, and electrical stimulation. It is suggested that in similar cases of delayed union, or where a large amount of bone has been resected from the radius and there is a significant risk of fracture or where fracture has occurred intraoperatively, the possibility of primary bone grafting should be considered.

Adult↗