Biomedical subjects

D G Kelly

Publications and source records attributed to D G Kelly.

77 records · Page 5Linked to original sources

PubMedDate not supplied

Should patients with a pre-operative prostate-specific antigen greater than 15 ng/ml be offered radical prostatectomy?

BACKGROUND: Patients with prostate cancer with a pre-operative prostate-specific antigen (PSA) >15 ng/ml who undergo radical retropubic prostatectomy (RRP) generally do not have a good outcome, yet may have organ-confined cancer and should be offered the option of surgery. AIM: To assess the outcome of patients who underwent RRP with a pre-operative PSA >15 ng/ml. METHODS: Thirty-four patients, mean pre-operative PSA: 25.46 ng/ml (15.03-76.6) and mean Gleason score: 6.4 (5-9) were assessed. RESULTS: Two groups were identified. Group I: 41% (14/34) have no biochemical recurrence to mean follow up of 58 months (30-106). Mean PSA: 18.8 ng/ml (15.03-25.84). Mean Gleason score: 6.1 (5-7). Clinical stage: T1c in 80%. No patient had seminal vesicle or lymph node involvement. Group II: 59% (20/34) have biochemical recurrence or died (3) from their disease to mean follow up of 66 months (36-98). Mean PSA: 28.9 ng/ml (15.28-76.6). Mean Gleason score: 6.7 (5-9). Clinical stage: T1c in 25%. Eleven patients had seminal vesicle (8) involvement or positive lymph nodes (3) or both (2). CONCLUSION: RRP seems feasible in patients whose pre-operative PSA is between 15 and 25 ng/ml with stage T1c, Gleason score < or = 7 and negative lymph node frozen section.

Adenocarcinoma↗

PubMedDate not supplied

The management of ureteric calculi without extracorporeal shock-wave lithotripsy.

BACKGROUND: Extracorporeal shock-wave lithotripsy (ESWL) is a relatively new technological adjunct in the treatment of renal calculi, but availability is limited. AIM: The aim of this study was to assess the outcome of ureteroscopic procedures in a unit without on-site ESWL facility. METHODS: A retrospective study of all cases of ureteric calculi presenting to this hospital during the period 1991 to 1997 was performed. RESULTS: One hundred and thirty five patients with a mean age of 46.8 years were evaluated. Ninety-four (69.5%) had their stone successfully manipulated and/or extracted at ureteroscopy. Using strict criteria, 41 patients (30.5%) had failed ureteroscopies. Fourteen (10.4%) suffered complications related to their ureteroscopy, thirteen had their complications treated conservatively and three (2.3%) needed open procedures. CONCLUSION: Ureteroscopy has a high success rate and low morbidity. We continue to advocate ureteroscopy in the initial management of ureteric calculi.

Humans↗

PubMedDate not supplied

Minicolumnar organization within somatosensory cortical segregates: I. Development of afferent connections.

This series of two articles develops a hypothesis on the modular organization of somatosensory cortex. The hypothesis is built around two functional entities: the segregate, a discrete somatosensory cortical macrocolumn approximately 0.5 mm in diameter, and the minicolumn, a smaller column approximately 0.05 mm in diameter, 40-80 of which make up a segregate. The hypothesis proposes that during perinatal development, minicolumns, acting via their short-range inhibitory and longer-range excitatory lateral connections, play an important role in the selection of thalamic connections to neighboring minicolumns. More specifically, the thalamic connections to each minicolumn are shaped by the interaction of that minicolumn primarily with those neighbors that belong to the same segregate. The outcome of this within-segregate self-organizational process is that (1) the minicolumns in a segregate acquire a complex but orderly pattern of afferent connections; (2) this connectional pattern, along with lateral inhibition, gives the minicolumns diverse receptive fields, arranged in a shuffled but orderly manner; and, most importantly, (3) the minicolumns and the segregate as a whole acquire a variety of stimulus feature-extracting properties. A computer-based model of a segregate is developed to show that under conditions found in the developing cerebral cortex, the thalamocortical connections within a segregate readily form complex patterns as proposed by the hypothesis. Furthermore, the connectional patterns developed by the model segregate, its receptive field organization, and its feature-extracting properties (the latter are described in the following article) reproduce many experimentally observed features of real cortical networks.

Animals↗

PubMedDate not supplied

Minicolumnar organization within somatosensory cortical segregates: II. Emergent functional properties.

In this article we describe some functional properties of the model of a somatosensory cortical macrocolumn--the segregate--described in the preceding companion article. These functional properties emerged in the model network in the course of stimulus-driven self-organization of its afferent connections under control of short-range inhibitory and longer-range excitatory lateral interactions among its minicolumns. In general, self-organization leads the model network to develop complex, nonlinear functional properties, and makes its neurons sensitive to the shape and temporal features of peripheral stimuli. The properties acquired reproduce some of the known properties of somatosensory and visual cortical networks. In particular, it is shown that, even though the network is exposed only to stationary point stimuli during self-organization, neurons in the model still acquire the ability to discriminate the direction of a moving stimulus, as well as the orientation of a stationary bar stimulus. Different stimulus directions and orientations are represented by different neurons in the model network, and the maps of neurons having these preferences have many properties in common with real cortical maps. In addition, we demonstrate the model network's ability to discriminate among spatially complex stimuli, such as letters of the alphabet. The parallels between the emergent structural and functional properties of the model network and the properties of sensory neocortex suggest that the model captures some of the basic mechanisms by which sensory cortical modules develop and maintain their elegantly detailed and appreciable information-processing capabilities.

Histocytochemistry↗

PubMedDate not supplied

Spontaneous separation and migration of a metal splice segment of a repaired Hickman catheter.

Repairs to the external silicone central venous catheter segment are done to correct mechanical defects caused by natural wear and tear or traumatic catheter injury. The ability to repair a damaged catheter obviates the need for surgical replacement. Complications specific to repaired Hickman catheters have not been reported. We report a case in which the metal piece separated from the replacement segment of a Hickman catheter. This metal piece lodged 1 cm from the catheter entrance to the anterior chest and caused incomplete catheter occlusion.

Catheterization, Central Venous↗