Biomedical subjects

A D Smith

Publications and source records attributed to A D Smith.

At least 289 records · Page 16Linked to original sources

PubMed1990

Effects of contextual integration on recall of pictures by older adults.

This study investigated age-related differences in the ability to utilize integrative relationships between target and context as a memory support by directly manipulating the relationship between a target picture and context. We hypothesized that as the active integration required between target and cue increased, age differences would increase. Old and young adults were instructed to remember target pictures, each presented with a pictorial cue. The cue/target relationship was one of three types: categorically related (high integration condition), visually interacting (high integration condition), or unrelated and noninteracting (low integration condition). Cued recall of the targets was tested. The results indicated that the poorly integrated target-context relationship produced the largest age difference, supporting the integration hypothesis.

Adolescent↗

PubMed1990

Age differences in memory for concrete and abstract pictures.

There is considerable experimental literature showing that memory for complex pictures is relatively insensitive to age. Previous research has shown that young and old adults do not differ in their ability to recognize complex scenes. Other studies, however, using simple line drawings, do find age differences. This experiment investigated the possibility that the failure to find age differences with memory for complex pictures occurs because of memory support provided at encoding and retrieval by both the degree of visual detail (complex perceptual information) and the degree of propositional content (linguistic meaningfulness) that are represented in complex scenes. Pictures were shown to young and old subjects that differed in visual detail (complex vs simple) and propositional content (concrete vs abstract). The results indicated that age differences in picture memory emerge if the pictures are either deprived of visual detail or reduced in propositional content.

Adult↗

PubMed1990

Red blood cell and adipose tissue fatty acids in mild inactive multiple sclerosis.

The fatty acid profiles of phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC) of the red blood cells of 30 patients with mild inactive multiple sclerosis (MS) and 30 healthy controls were studied by gas chromatography. The groups were well matched for factors likely to influence tissue lipid levels, including diet. The MS patients showed a significant reduction in PE eicosapentaenoic acid (p = 0.009) especially in women, and an increase in both PE dihomo-gamma-linolenic acid (p = 0.004) and PC stearic acid (p = 0.04). No reduction in linoleic acid was observed in either the PC or PE fractions of the MS subjects. A similar study of the fatty acid profile in adipose tissue in 26 MS and 35 healthy controls found no detectable eicosapentaenoic acid in either group. However, whereas docosahexaenoic acid was not detectable in any MS patient, 40% of the controls had measurable levels varying from to 0.1 to 0.3% of total estimated fatty acid (p = 0.0003). No reduction in linoleic acid in MS subjects was observed. Supplementation with oral fish body oil demonstrated that n-3 fatty acids were incorporated into red blood cells over 5 weeks and this occurred equally in MS and controls. The effects of oral supplementation on adipose tissue were studied after 1 and 2 years. Whereas many fatty acids such as linoleic acid were raised at 1 year, but did not rise subsequently, eicosapentaenoic acid and docosahexaenoic acid continued to rise through the 2-year period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1990

Metamemories of memory researchers.

In the present study, a metamemory questionnaire was completed by three groups of individuals: memory research psychologists who attended a small international convention on everyday memory processes in the aged, academic psychologists with a limited knowledge of the memory literature, and nonpsychologist college professors. There was little evidence that memory psychologists reported using strategies to remember things that were different from the strategies of other academics. The most used and most recommended technique for remembering was to write things down, followed by general internal mnemonic systems such as organization and rehearsal. The least used and least recommended strategies for all three groups were formal mnemonic systems, such as the peg-word system or the method of loci.

Adult↗

PubMed1990

Management of benign prostatic hyperplasia. Alternatives to standard therapy.

Benign prostatic hyperplasia is a significant cause of morbidity in the elderly male population. The standard therapy for symptomatic prostatic obstruction has been prostatectomy by transurethral resection (TURP) or, less frequently, by open surgery. Innovative alternative treatments of benign prostatic hyperplasia, both surgical and nonsurgical, will be discussed. Additionally, an appraisal of TURP will be made.

Adrenergic alpha-Antagonists↗

PubMed1990

Therapeutic options for the management of upper tract calculi.

The cry of "ESWL for all" was heard at the 84th Annual Meeting of the American Urological Association, and actually, this is not far from the truth. Those physicians who are not familiar with percutaneous techniques, or who do not have the necessary equipment available, may actually attempt ESWL for all calculi regardless of stone burden or location. Patients who are interested in avoiding manipulation may request ESWL, even if the results may not be as good as those obtained with concomitant manipulation or with percutaneous procedures. Nevertheless, indications still exist for percutaneous techniques, and these procedures will not become obsolete even as ESWL technology advances. Studies are being conducted to identify the ideal treatment for all varieties of stones in the genitourinary system. As ESWL and endoscopic technology continue to advance, the treatment of stone disease will continue to change.

Humans↗

PubMed1990

Benefits of an ultrasound-guided ESWL unit.

Ultrasound is ideally suited for imaging of renal calculi for extracorporeal shock wave lithotripsy. Ultrasound can localize radiolucent stones, monitor fragmentation in real time, and differentiate the stone from a stent. Its use significantly reduces the radiation exposure to patient and operator, which is particularly desirable in the pediatric patient. Furthermore, sonography-guided lithotripsy can reveal any incidental finding in the affected kidney that may require further evaluation and familiarizes the operator with this increasingly useful imaging method. The ultrasound-guided Sonolith 3000 with its enlarged ellipsoid aperture has a decreased energy focus size and voltage, permitting fragmentation with reduced anesthesia requirements. The initial extracorporeal shockwave lithotripsy (ESWL) machine, the Dornier H3, uses fluoroscopy for stone localization and treatment monitoring. Although this imaging method has the benefit of being familiar to urologists, it has some drawbacks, such as difficulty in imaging some types of stones and the radiation exposure of the operator and the patient. We have been using the Technomed Sonolith 3000 ESWL machine, which uses ultrasound to localize stones. During this experience, we have found a number of obvious and not so obvious benefits. For example essentially all calculi are echogenic, irrespective of their radiologic density. Moreover, with ultrasound, fragmentation can be monitored by real-time imaging, making determination of the treatment end point easier, and the stone and stent can be differentiated clearly. Ultrasound also can reveal other pathology and eliminates radiation exposure. Moreover, an ultrasound-guided ESWL unit familiarizes the operator with ultrasound techniques, and the same machine can be used for biliary lithotripsy. All of these features make ultrasound imaging for ESWL desirable.

Evaluation Studies as Topic↗

PubMed1990

Greenberg surgical support system for the endourologist.

As the field of endourology diversifies, the importance of ergonomics grows. The technology developed to assist the endourologist may accomplish the surgical goals effectively, but it often does not consider instrument control, planning of space, and the physical comfort of the operator. The Greenberg retractor creates a surgical environment that improves the urologist's efficiency and technical proficiency. Complex staghorn cases can be performed with reduced risk of inadvertent damage to renal tissue, no shifts of the nephroscope, and a more productive experience for the assistant.

Humans↗

PubMed1990

Intraoperative endourologic urethral manipulation.

These simple techniques are rapid and efficient ways to deal with intraoperative difficulties. The equipment required is readily available in most operating rooms where endourologic procedures are performed. The techniques can obviate open surgical procedures, thus decreasing the morbidity to the patient and creating significant cost savings for the provider.

Catheters, Indwelling↗

PubMed1990

Percutaneous bladder procedures.

Endourology must now include lower urinary tract pathology. The above techniques utilize equipment that is readily available in most centers performing percutaneous procedures. As with the upper tract endourology, the procedures performed in the bladder are likely to reduce morbidity and hospital stay, and in fact, many of these procedures are performed in the office setting under local anesthesia. Our experience was initially in the geriatric population but has now expanded widely, and we use this approach primarily in many bladder cases.

Abscess↗

PubMed1990

Advances in the percutaneous management of the ureteropelvic junction and other obstructions of the urinary tract in children.

In conclusion, endopyelotomy has been developed over the past several decades on the basis of sound laboratory and clinical research. The success rates have been similar to those of the standard open pyeloplasty, and the procedure is not associated with undue complications. Endopyelotomy has several distinct advantages over open surgery, including the decreased morbidity and associated expense of an open operation, minimal interference with the blood supply of the ureter, and avoidance of removal of the ureter from its natural sheath, preventing the tendency to adhere to adjacent structures and thus kink. As the instrumentation available for percutaneous renal surgery has improved and been miniaturized, the techniques developed in adults have been progressively applied to younger and smaller children. There seems to be little doubt that a comparison of morbidity and socioeconomic factors associated with a successful endopyelotomy versus an open pyeloplasty in adults heavily favors the percutaneous procedures, and judicious application to children would seem warranted. However, the changing presentation of ureteropelvic junction obstruction in children that has resulted from the widespread use of prenatal ultrasonography may make the question moot. Open infant pyeloplasty is a highly successful procedure, accompanied by minimal morbidity and accomplished in a 2- to 3-day hospital stay. The socioeconomic factors are obviated in the infant, who already requires constant maternal care. However, endopyelotomy deserves consideration in the older child, especially if the obstruction is secondary in nature after a previous open procedure.

Child↗

PubMed1990

Conservative management for transitional cell carcinoma of the upper urinary tract.

Transitional cell carcinoma of the upper urinary tract most frequently occurs in the sixth and seventh decades of life. Standard care for these tumors involves a nephroureterectomy with removal of a cuff of bladder. Many investigators now recommend parenchymal-sparing operations in selected patients to avert the previous inevitability of dialysis. Recently, advancements in endoscopic technology have afforded two new, less invasive complementary techniques for the diagnosis and treatment of these lesions: ureteroscopy and nephroscopy. Ureteroscopy, due to its less invasive nature, is generally used as a first line approach to diagnosis and treatment. Those tumors which are not accessible from a ureteroscopic approach or are simply too large for adequate resection may be excised by nephroscopic means. Early results of endoscopic intervention appear to be comparable to open parenchymal-sparing procedures.

Aged↗

PubMed1989

Laser treatment of transitional cell cancer of the bladder and upper urinary tract.

Nd:YAG laser therapy now has a well-defined role in the treatment of superficial bladder cancer, that is, it is indicated only when one needs to destroy present tumors. Available results suggest that tumor recurrence is reduced, but definitive evidence of this is lacking. The laser's main advantage is that the procedure is carried out without anesthesia on an outpatient basis, because it is a noncontact technique that is associated with minimal morbidity and reduced pain and bleeding. Nd:YAG laser use in invasive bladder cancer would appear to be adequate for palliation only. For this indication, its benefits must be compared with conventional palliative TUR and/or radiation therapy. Laser therapy of tumors in the upper urinary tract is still in its infancy. Urothelial cancer is a multifocal disease, and the critical caveat, as in the case of bladder cancer, is tumor recurrence. Routine access to the upper tract and accurate assessment of the grade and stage of the tumor and the multifocality of the disease are of paramount importance and are not yet perfected. Photodynamic therapy is an intriguing modality. It has much potential for future development, but at present, because of its reduced ability to control superficial cancer, particularly when compared with other available forms of treatment such as intravesical BCG, and because of its significant associated morbidity, its use remains investigational.

Argon↗

PubMed1989

Uptake and retention of strontium, iodine and caesium in lowland pasture following continuous or short-term deposition.

Data from the extensive routine environmental monitoring programme around the nuclear reprocessing plant at Sellafield, West Cumbria, are analysed for soil to plant uptake of strontium, iodine and caesium. Relative to the top 10 cm of soil, dry weight concentration ratios derived for lowland pastures for strontium, caesium and iodine are 9, 3 and 2 respectively. Long-term trends indicate a 'spring flush' of activity in vegetation, although this is not statistically significant. Uptake of caesium and iodine is highest generally for mosses and lichen and lowest for grass. The vegetational field loss of these elements over the first 50 days following deposition, is described by: Sr: Reff(t) = 0.7e-0.15t + 0.25e-0.049t + 0.05e-0.011t I: Reff(t) = 0.7e-1.26t + 0.25e-0.17t + 0.05e-0.092t Cs: Reff(t) = 0.6e-0.87t + 0.2e-0.20t + 0.16e-0.065t + 0.04e-0.011t where t is in days. The functions are consistent with the effects of washoff and grazing. Equilibrium plant:soil concentration ratios are established for caesium within about 8 months following short-term deposition. Soil distribution profiles for caesium imply a half-time for transfer through the surface layers of about 6 years.

Cesium Radioisotopes↗

PubMed1989

Renal effects of percutaneous stone removal.

Preoperative and postoperative renography with 99mTechnetium-diethylene-triamine pentaacetic acid was performed on 33 patients who were free of renal scarring, infection, and obstruction and who underwent percutaneous renal stone removal. Although there was a transient decrease in renal function postoperatively in some patients, statistically significant reductions in renal function occurred only in 1 patient with an arteriovenous malformation that was embolized and in 1 patient who had a postoperative ureteropelvic junction stricture. The creation of more than one nephrostomy tract did not affect the results. In the absence of serious complications, percutaneous nephrostomy does not have a significant effect on renal function.

Adult↗

PubMed1989

Impact of percutaneous renal stone removal on renal function: assessment by urinary lysozyme activity.

Lysozyme in the urine in concentrations greater than 3 micrograms per milligram of creatinine reflects renal tubular disease or dysfunction in patients without bowel disease or leukemia. We therefore used urine lysozyme assays to assess renal response to percutaneous nephrostomy and stone removal in 42 patients. Eight patients had striking increases (4.2-21.1 [mean 7.58] micrograms/mg creatinine) immediately after nephrostomy puncture in urine obtained directly from the punctured kidney. Lysozyme declined sharply thereafter and was within normal limits in all cases by postoperative day 3. This increase appeared to result from bleeding into the urine from the tract. Five other patients had lysozymuria on admission, only 1 of whom had a sharp increase after nephrostomy puncture. In the remaining patients, the lysozyme levels remained within normal limits throughout the hospital course. These data are further evidence of the absence of significant deleterious effects of nephrostomy puncture on the kidney.

Acute Kidney Injury↗

PubMed1989

Approaches to the superior calix: renal displacement technique and review of options.

A new percutaneous approach to the superior calix has been implemented with reduced morbidity. To avoid intercostal or retrograde punctures or triangulation methods an Amplatz sheath passed through a central or lower pole calix can be pushed caudally while descent of the kidney is viewed fluoroscopically. An 18-gauge TLA needle passed through the initial skin puncture then is used to form a Y with the original tract. This method has been successful in 21 of 25 cases without complications. The only failures occurred in patients with immobile kidneys secondary to a previous operation.

Fluoroscopy↗

PubMed1989

Effects of age and a divided attention task presented during encoding and retrieval on memory.

The present studies were designed to examine age differences in memory when attention was divided during encoding, retrieval, or at both times. In Experiment 1, Ss studied categorized words while performing a number-monitoring task during encoding, retrieval, or at both times. Older Ss' free recall and clustering performance declined more than that of young Ss when attention was divided at encoding, but there was no similar age interaction when divided attention occurred at retrieval. In Experiment 2, the task demands at retrieval were increased by using a fast-paced, cued-recall task. The results remained unchanged from Experiment 1. Again, an age interaction occurred with divided attention at encoding but not at retrieval. These results were unexpected, given the emphasis in the memory-aging literature on increased difficulty of retrieval by older adults. The findings pose difficulties for limited processing resource views of age differences in memory.

Adult↗