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Biomedical subjects

J Coleman

Publications and source records attributed to J Coleman.

At least 163 records · Page 9Linked to original sources
PubMed1977

The visual cortex of the opossum: the retrograde transport of horseradish peroxidase to the lateral geniculate and lateral posterior nuclei.

The visual cortex of opossum was studied by injecting horseradish peroxidase into the cortex and identifying labeled neurons in the thalamus. The results show that the lateral geniculate nucleus projects to area 17 in a topographical manner: the rostral lateral geniculate is represented in caudal striate cortex, and the dorsal extremity of the lateral geniculate, which probably corresponds to the zero vertical meridian, is represented along the border of area 18. Small injections in area 17 produced restricted bands of labeled neurons across the medial-lateral extent of the lateral geniculate, suggesting a greater precision in the topography than previously shown by retrograde degeneration studies. Following injections into area 17, labeled cells were also found in the lateral posterior nucleus. Injections of peristriate cortex produced labeled cells in the lateral posterior nucleus, as well as the lateral intermediate, posterior and intralaminar nuclei. Since the lateral posterior nucleus receives visual projections from the superior colliculus, the results show two visual pathways: the geniculo-striate path projecting just to core area or area 17, and a more diffuse parallel path that projects to both the core and belt. Whether or not this overlap is characteristics of the mammalian prototype it seems to be present in widely separated species.

Animals↗
PubMed1976

Pilocarpine therapy in glaucoma: effects on anterior chamber depth and lens thickness in patients receiving long-term therapy.

The effect of pilocarpine hydrochloride on the anterior chamber depth and lens thickness was measured in 20 eyes of patients with chronic open-angle glucoma who were receiving long-term glaucoma therapy with pilocarpine. Measurements were made with high-resolution ultrasonic biometry. This study demonstrated that regardless of their age (58.4 years, average) and the fact that they had been regularly using pilocarpine from two to four times a day, 85% of these patients demonstrated narrowing of the anterior chamber (AC) depth (average, 0.19 mm) and thickening of the lens (average, 0.21 mm) with each instillation of pilocarpine. In approximately 15% of eyes, a repeatable deepening of the AC depth and flattening of the lens was noted.

Administration, Topical↗
PubMedDate not supplied

Resected adenocarcinoma of the pancreas-616 patients: results, outcomes, and prognostic indicators.

This large-volume, single-institution review examines factors influencing long-term survival after resection in patients with adenocarcinoma of the head, neck, uncinate process, body, or tail of the pancreas. Between January 1984 and July 1999 inclusive, 616 patients with adenocarcinoma of the pancreas underwent surgical resection. A retrospective analysis of a prospectively collected database was performed. Both univariate and multivariate models were used to determine the factors influencing survival. Of the 616 patients, 526 (85%) underwent pancreaticoduodenectomy for adenocarcinoma of the head, neck, or uncinate process of the pancreas, 52 (9%) underwent distal pancreatectomy for adenocarcinoma of the body or tail, and 38 (6%) underwent total pancreatectomy for adenocarcinoma extensively involving the gland. The mean age of the patients was 64.3 years, with 54% being male and 91% being white. The overall perioperative mortality rate was 2.3%, whereas the incidence of postoperative complications was 30%. The median postoperative length of stay was 11 days. The mean tumor diameter was 3.2 cm, with 72% of patients having positive lymph nodes, 30% having positive resection margins, and 36% having poorly differentiated tumors. Patients undergoing distal pancreatectomy for left-sided lesions had larger tumors (4.7 vs. 3.1 cm, P < 0.0001), but fewer node-positive resections (59% vs. 73%, P = 0.03) and fewer poorly differentiated tumors (29% vs. 36%, P < 0.001), as compared to those undergoing pancreaticoduodenectomy for right-sided lesions. The overall survival of the entire cohort was 63% at 1 year and 17% at 5 years, with a median survival of 17 months. For right-sided lesions the 1- and 5-year survival rates were 64% and 17%, respectively, compared to 50% and 15% for left-sided lesions. Factors shown to have favorable independent prognostic significance by multivariate analysis were negative resection margins (hazard ratio [HR] = 0.64, confidence interval [CI] = 0.50 to 0.82, P = 0.0004), tumor diameter less than 3 cm (HR = 0.72, CI = 0.57 to 0.90, P = 0.004), estimated blood loss less than 750 ml (HR = 0.75, CI = 0.58 to 0.96, P = 0.02), well/moderate tumor differentiation (HR = 0.71, CI = 0.56 to 0.90, P = 0.005), and postoperative chemoradiation (HR = 0.50, CI = 0.39 to 0.64, P < 0.0001). Tumor location in head, neck, or uncinate process approached significance in the final multivariate model (HR = 0.60, CI = 0.35 to 1.0, P = 0.06). Pancreatic resection remains the only hope for long-term survival in patients with adenocarcinoma of the pancreas. Completeness of resection and tumor characteristics including tumor size and degree of differentiation are important independent prognostic indicators. Adjuvant chemoradiation is a strong predictor of outcome and likely decreases the independent significance of tumor location and nodal status.

Adenocarcinoma↗
PubMedDate not supplied

Should pancreaticoduodenectomy be performed in octogenarians?

As the population in the United States ages, an increasing number of elderly patients may be considered for pancreaticoduodenal resection. This high-volume, single-institution experience examines the morbidity, mortality, and long-term survival of 727 patients undergoing pancreaticoduodenectomy between December 1986 and June 1996. Outcomes of patients 80 years of age and older (n = 46) were compared to those of patients younger than 80 years. In these older patients, pancreaticoduodenectomy was performed for pancreatic adenocarcinoma (n = 25; 54%), ampullary adenocarcinoma (n = 9; 20%) distal bile duct adenocarcinoma (n = 5; 11%), duodenal adenocarcinoma (n = 2; 4%), cystadenocarcinoma; (n = 2; 4%), cystadenoma (n = 1; 2%), and chronic pancreatitis (n = 2; 4%). When compared to the 681 concurrent patients younger than 80 years who were undergoing pancreaticoduodenectomy, the two groups were statistically similar with respect to sex, race, intraoperative blood loss, and type of pancreaticoduodenectomy performed. Patients 80 years of age or older had a shorter median operative time (6.4 hours vs. 7.0 hours; P = 0.02) but a longer postoperative length of stay (median = 15 days vs. 13 days; P = 0.01) and a higher complication rate (57% vs. 41%; P = 0.05) when compared to their younger counterparts. Pancreaticoduodenectomy in the older group resulted in a 4.3% perioperative mortality rate compared to 1.6% in the younger group (P = NS). In the subset of patients undergoing pancreaticoduodenectomy for periampullary adenocarcinoma (n = 495), patients 80 years of age or older (n = 41) had a median survival of 32 months and a 5-year survival rate of 19%, compared to 20 months and 27%, respectively, in patients younger than 80 years (n = 454; P = 0.77). These data demonstrate that pancreaticoduodenectomy can be performed safely in selected patients 80 years of age or older, with morbidity and mortality rates approaching those observed in younger patients. Based on these data, age alone should not be a contraindication to pancreaticoduodenectomy.

Adenocarcinoma↗
PubMedDate not supplied

A novel immune system against bacteriophage infection using complementary RNA (micRNA).

The "operon' theory of gene regulation, in which protein repressor molecules bind to the operator site of a gene to prevent its transcription, is now well established. Recently, however, cases have been discovered in which gene expression is regulated by complementary RNA molecules that are able to bind to the transcripts of particular genes and consequently prevent their translation. For example, the synthesis of OmpF protein (a major outer membrane protein) in Escherichia coli is regulated by a short RNA complementary to a region of ompF RNA encompassing the "Shine-Dalgarno' sequence and the translation initiation codon. This RNA has been termed micRNA (messenger-RNA-interfering complementary RNA), and its discovery has prompted us to construct an artificial micRNA system designed to regulate gene expression in E. coli. A given target gene can be repressed by artificially producing an RNA (micRNA) complementary to the mRNA encoded by that gene. A micRNA system has also been used successfully in tissue-cultured mammalian cells. The use of artificial micRNAs to specifically regulate individual genes has great potential as a novel cellular immune system for blocking bacteriophage or virus infection. Here, we report that on induction of micRNAs directed against the coat protein and/or the replicase of the E. coli bacteriophage SP, phage proliferation was effectively prevented. We propose that the micRNA immune system provides an effective means of preventing viral infection as well as the expression of harmful genes in both prokaryotes and eukaryotes.

Base Sequence↗