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Biomedical subjects

A D Smith

Publications and source records attributed to A D Smith.

At least 325 records · Page 18Linked to original sources
PubMed1988

Management of ureteroscopic ureteral injuries.

Ureteroscopy will continue to have a place in the management of renal stone disease and is invaluable to evaluate other types of ureteral lesions. Although ureteroscopy can be performed safely in most cases, it is invasive and there is a potential for ureteral injury. The well-trained urologic surgeon should be familiar with techniques to minimize the incidence of complications of ureteroscopy. However, faced with a ureteral complication, no matter the severity, the surgeon should have the ingenuity and expertise to restore anatomic integrity to the renal unit.

Endoscopy↗
PubMed1988

Degeneration of serotonin-specific neurons in the brain in experimental Trypanosoma brucei infection.

ORMEROD and HUSSEIN (1986) have shown that an intracellular stage of Trypanosoma brucei rhodesiense causes the destruction of ependymal cells lining the ventricles of the brain. The ventricular ependymal cells are intimately associated with a plexus of nerves that react specifically with monoclonal antibody raised against serotonin. We have shown that in areas where the ependyma is damaged, the supraependymal plexus also undergoes destruction and that retrograde degeneration of the neuron as far as the dorsal raphe nucleus also occurs. Although the work is as yet unfinished, we suggest that some of the neuro-psychological changes, observed in clinical sleeping sickness, may be the result of this lesion.

Animals↗
PubMed1988

Psychologic factors in the multidisciplinary evaluation and treatment of erectile dysfunction.

The members of a multidisciplinary team treating sexual dysfunction must work together from different perspectives and training to determine an accurate diagnosis, choose an appropriate treatment, and evaluate those treatments systematically. Integrating data from both physical and psychologic evaluations is essential. Anxiety, depression, or other reactions to stress are seen as cognitive interferences that inhibit sexual arousal by distracting attention from erotic stimuli. The goals of sex therapy are to enhance attentional focus on sexual cues and to lessen distractions in the form of anxiety, conflict, or other stresses. Although there continue to be methodologic problems in outcome evaluation research of multidisciplinary treatment of sexual dysfunction, follow-up studies generally indicate improvements in sexual functioning, satisfaction, and self-esteem.

Ejaculation↗
PubMed1988

Endourology and ureteroscopy.

Over the past 10 years, endourology and ureteroscopy have revolutionized the field of urinary endoscopy. No longer limited to cystoscopic examination of the lower genitourinary tract, endoscopy incorporates the upper tracts as well. With this surge in upper tract endoscopy has come a rise in the variety of medical instruments available to the endourologist. Beginning with rigid instruments that offered only a limited view, technology has advanced both flexible and rigid instruments that allow access to the entire urinary tract for examination and treatment. Lenses have been designed to give a clearer and wider view of the kidney and ureter, and forceps and graspers have been developed to treat the underlying pathologic conditions. Stents, wires, and nephrostomy tubes have been developed to keep the urinary system patent and readily accessible for reexamination. It is only through the continuous improvement of these instruments that endourology has advanced in the frontier of urologic surgery.

Endoscopes↗
PubMed1988

Anatomy of the ureter.

Ureteral anatomy is vital to the endoscopist as this knowledge will facilitate the endoscopic manipulation of the ureter and minimize the morbidity that can be associated with these procedures.

Endoscopy↗
PubMed1988

Mechanical extraction of stones with rigid ureteroscopes.

Ureteroscopy, once the province of experienced endourologists, is now being done routinely by nearly all urologists. Thorough preoperative evaluation, proper selection of instruments, and gentle manipulation will lead to stone retrieval with minimal sequelae.

Endoscopes↗
PubMed1988

Percutaneous treatment of transitional cell carcinoma of the upper urinary tract.

Fourteen selected patients with renal pelvic transitional cell carcinoma were managed percutaneously in our institution between March 1984 and April 1987. With a mean follow-up of 19 months, and excluding those patients who underwent immediate nephroureterectomy, six patients remain free of recurrent disease, which is similar to the results obtained with open parenchyma-sparing conservative operations. Our results suggest that percutaneous operations can provide cure in selected patients, including those with a normal contralateral kidney and with small (no more than 2-cm), single, low-grade, papillary tumors that are confined to the mucosa who, in addition, have negative cytology, negative random biopsies of contiguous mucosa, and no history of or concurrent transitional cell carcinoma elsewhere in the urinary tract. Further, our results suggest that second-look procedures with resection of suspicious residual disease, Nd:YAG laser irradiation of the tumor bed, and intracavitary administration of BCG all appear to help prevent recurrences.

Administration, Topical↗
PubMed1988

Endopyelotomy.

Endopyelotomy has developed from the advances of endourology and has become an accepted means to correct ureteropelvic junction obstruction. Endopyelotomy can be performed with less morbidity than pyeloplasty, with less operative and anesthetic time, less analgesic requirements, and a shorter recovery period. With success rates of 88.8 per cent for primary obstruction and 89 per cent for secondary obstruction, provided patients are selected appropriately, endopyelotomy has become a valuable procedure for the correction of ureteropelvic junction obstruction. The longest follow-up is 4 years, and therefore long-term success rates cannot be quoted. Time will reveal the ultimate place for endopyelotomy.

Catheters, Indwelling↗
PubMed1988

Stent for endopyelotomy.

There can be no single ideal stent, as each individual need requires a different type of stent. For endopyelotomy, at the present time, we think we have a stent that meets most of the criteria we set. From past experience, we are sure there will be further modifications and improvements in our quest for the ideal stent for this indication.

Catheters, Indwelling↗
PubMed1988

Complications of endopyelotomy.

Endopyelotomy is safe with a low risk of complications and a high chance of success given satisfactory percutaneous access to the kidney, adequate incision of the ureteropelvic junction, and proper stenting. The benefits of endopyelotomy are considerable. The postoperative morbidity is much less than that of an open operation, and the technique requires much less time, which may reduce the cost. Furthermore, the ureteral blood supply is undisturbed, which is an important advantage should open pyeloplasty be necessary. Complications of endopyelotomy will be further reduced as urologists gain experience and familiarity with the various endourologic techniques required.

Catheters, Indwelling↗
PubMed1988

Percutaneous management of ureteral fistulas.

Ureteral occlusion with proximal urinary diversion is often required when treating patients with ureteral fistulas secondary to advanced neoplastic disease. Recent endourologic advancements have stemmed from the high morbidity and mortality associated with formal surgical reconstruction in this population. Endourologic management may be accomplished by a transrenal or retroperitoneal approach. To date, no study has clearly demonstrated the superiority of any one approach because of the small numbers of patients and the uniformly short-term follow-up.

Catheterization↗
PubMed1987

H.p.l.c. analysis of inositol monophosphate isomers formed on angiotensin II stimulation of rat adrenal glomerulosa cells.

[3H]Inositol-prelabelled isolated rat adrenal glomerulosa cells were stimulated with 25 nM-AII ([Asp1, Ile5]-angiotensin II) in the presence of 10 mM-Li+, and the resulting inositol monophosphate isomers were separated successfully by using a recently developed h.p.l.c. methodology. Two major peaks of radioactivity were detected which showed the same retention characteristics on h.p.l.c. as inositol 4-phosphate and inositol 1-phosphate and which increased 5-fold and 8-fold respectively on stimulation with AII. In addition, a relatively small peak with the retention characteristics of inositol 1:2-cyclic phosphate was seen to undergo a 1.5-fold increase on stimulation. This was not considered sufficient to suggest that cyclic phosphoinositols were a major product of AII-stimulated phosphoinositide turnover. No peaks of radioactive material were detected in the regions expected for inositol 2-phosphate (an acid hydrolysis product of inositol 1:2-cyclic phosphate) or inositol 5-phosphate. These results establish the identity of the major inositol phosphate products in AII-stimulated glomerulosa cells and confirm and extend the previous observations of Balla, Baukal, Guillemette, Morgan & Catt [(1986) Proc. Natl. Acad. Sci. 83, 9323-9327].

Adrenal Glands↗
PubMed1987

Resolution of the phosphoinositide-specific phospholipase C isolated from porcine lymphocytes into multiple species. Partial purification of two isoenzymes.

Phospholipase C isolated from porcine mesenteric lymph node lymphocytes was distributed between the soluble and particulate fractions. Enzyme activity was found predominantly in the soluble fraction with optimal activity at pH 5.5. Gel filtration chromatography of the soluble phospholipase C revealed that it was composed of multiple species of enzyme activity. The activity associated with the particulate fraction had optimal activity at pH 7.0, as also did one of the species of soluble phospholipase C. Cellulose phosphate chromatography resolved the major soluble form into two species designated PLC-A and PLC-B. Both phenyl-Sepharose chromatography and hydroxyapatite chromatography purified these species still further. PLC-A and PLC-B demonstrated similar activities against phosphatidylinositol with a pH optimum near 5.5. The phospholipase C activities were abolished against this substrate by the addition of 1 mM-EDTA. When assayed in the presence of Ca2+-EDTA buffers providing a range of Ca2+ free concentrations, both enzymes exhibited optimal activity near 10(-3) M free Ca2+, but PLC-B was inhibited above this concentration more than PLC-A. PLC-B exhibited markedly lower activity against phosphatidylinositol 4,5-bisphosphate, suspended as liposomes of the pure phospholipid, than did PLC-A.

Animals↗
PubMed1987

Modulation of membrane protein function by bilayer lipids.

In many instances, the composition of fatty acyl groups of membrane phospholipids can be modified to achieve a range of fatty acyl unsaturation without any detectable change in bulk membrane fluidity. At the same time, the function of membrane proteins may be considerably altered, raising questions concerning the property of the lipids that brings about this altered protein function. There is some evidence that the lipids may be laterally distributed in a heterogeneous manner throughout the membrane, and changes in this distribution could be responsible for the effects on proteins. There is also increasing evidence for specific interactions between individual molecular species and membrane proteins that may also modulate membrane protein function.

Animals↗
PubMed1987

Synaptic input and local output of dopaminergic neurons in grafts that functionally reinnervate the host neostriatum.

In adult rats with a unilateral 6-hydroxy-dopamine-induced lesion of the nigrostriatal dopamine pathway, grafts of embryonic ventral mesencephalon can establish extensive efferent connections with the previously denervated host neostriatum and can compensate for motor and sensorimotor asymmetries induced by the lesion. The object of this study was to examine the afferent synaptic inputs to grafted dopaminergic neurons, implanted into a cortical cavity overlying the previously denervated caudate-putamen, using electron microscopic immunocytochemistry. The dopaminergic neurons of the grafts in the same animals had previously been shown to re-innervate the host neostriatum, to form synaptic connections therein and to attenuate the lesion-induced motor asymmetry that occurred in response to amphetamine (Freund et al. 1985). In the light microscope, the grafts were found to contain numerous tyrosine hydroxylase-immunoreactive perikarya, dendrites, axons and axonal swellings which had distinct distributions. In addition axons and axonal swellings that were immunoreactive for either substance P or glutamate decarboxylase were present. Electron microscopic analysis of the boutons contacting tyrosine hydroxylase-immunoreactive neurons in the grafts revealed the presence of at least five distinct types of afferent synaptic boutons based on their immunochemistry, morphology, or types of membrane specialization. One type was itself immunoreactive for tyrosine hydroxylase; such synapses are extremely rare in the intact substantia nigra, none were found in the contralateral substantia nigrae or the substantia nigra of a control rat. Three of the remaining types had ultrastructural features that were similar to synaptic terminals that were immunoreactive for substance P or glutamate decarboxylase. These synapses were similar to the types of synapses found contacting dopaminergic neurons in the substantia nigra contralateral to the graft or the substantia nigra of a control rat. The results demonstrate that, in the absence of the normal extrinsic afferent inputs, the intracortical mesencephalic grafts have a well-developed local synaptic circuitry. It is suggested that local circuit regulation of dopaminergic neurons within the graft may, at least in part, be responsible for the maintenance of a normal or close to normal functional activity.

Animals↗