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Biomedical subjects

E George

Publications and source records attributed to E George.

At least 55 records · Page 3Linked to original sources
PubMed1997

Responses of Picea, Pinus and Pseudotsuga roots to heterogeneous nutrient distribution in soil.

The spatial distribution of plant-available mineral nutrients in forest soils is often highly heterogeneous. To test the hypothesis that local nutrient enrichment of soil leads to increased root proliferation in the nutrient-rich soil zone, we studied the effects of nutrient enrichment on the growth and nutrient concentrations of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) roots. Three-year-old seedlings were grown for 9 months in split-root containers filled with nutrient-poor forest mineral soil, with one side supplemented with additional mineral nutrients. Root dry weight and root length in Scots pine and Norway spruce were increased in the nutrient-supplemented soil compared with the nonsupplemented side, whereas root growth in Douglas-fir was unaffected by nutrient enrichment. Of the three species examined, Norway spruce exhibited the highest root and shoot growth and the highest nutrient demand. Specific root length (m g(-1)) and the number of root tips per unit root length were not affected by local nutrient addition in any of the species. Despite increased root growth in Norway spruce and Scots pine in nutrient-supplemented soil, their root systems contained similar nutrient concentrations on both sides of the split-root container. Thus, coniferous trees may respond to local nutrient supply by increased root proliferation, but the response varies depending on the species, and may only occur when trees are nutrient deficient. As a response to local nutrient enrichment, increases in root dry matter or root length may be better indicators of pre-existing nutrient deficiencies in conifers than increases in root nutrient concentrations.

Journal Article↗
PubMed1997

The use of tolbutamide-induced hypoglycemia to examine the intraislet role of insulin in mediating glucagon release in normal humans.

Disruption of intraislet mechanisms could account for the impaired glucagon response to hypoglycemia in type 1 diabetes. However, in contrast to animals, there is conflicting evidence that such mechanisms operate in humans. We have used i.v. tolbutamide (T) (1.7 g bolus + 130 mg/h infusion) to create high portal insulin concentrations and compared this with equivalent hypoglycemia using an i.v. insulin infusion (I) (30 mU/m2 x min). Ten normal subjects underwent two hypoglycemic clamps; mean glucose; I (53 +/- 1 mg/dL); and T (53 +/- 1 mg/dL) (2.9 +/- 0.04 mmol/L vs. 2.9 +/- 0.05 mmol/L), held for 30 min. During hypoglycemia, mean peripheral insulin levels were greater with I (59 +/- 4 mU/L) than T (18 +/- 3 mU/L), P < 0.001. Calculated peak portal insulin concentrations were greater during T (282 +/- 28 mU/L) than I (78 +/- 4 mU/L), P < 0.00005. The demonstration of a reduced glucagon response during T-induced hypoglycemia (111 +/- 8 ng/L vs. 135 +/- 12 ng/L, P < 0.05) with higher portal insulin concentrations suggests that intraislet mechanisms may contribute to the release of glucagon during hypoglycemia in man.

Adult↗
PubMed1997

Preservation of physiological responses to hypoglycemia 2 days after antecedent hypoglycemia in patients with IDDM.

OBJECTIVE: To assess the effects of short-term antecedent hypoglycemia on responses to further hypoglycemia 2 days later in patients with IDDM. RESEARCH DESIGN AND METHODS: We studied eight type I diabetic patients without hypoglycemia unawareness or autonomic neuropathy during two periods at least 4 weeks apart. On day 1, 2 h of either clamped hyperinsulinemic (60 mU.m-2.min-1) hypoglycemia at 2.8 mmol/l or euglycemia at 5.0 mmol/l were induced. Hyperinsulinemic hypoglycemia was induced 2 days later with 40 min glucose steps of 5.0, 4.0, 3.5, 3.0, and 2.5 mmol/l. Catecholamine levels and symptomatic and physiological responses were measured every 10-20 min. RESULTS: When compared with the responses measured following euglycemia, the responses of norepinephrine 2 days after hypoglycemia were reduced (peak, 1.4 +/- 0.4 [mean +/- SE] vs.1.0 +/- 0.3 nmol/l [P < 0.05]; threshold, 3.4 +/- 0.1 vs. 2.9 +/- 0.1 mmol/l glucose [P < 0.01]). The responses of epinephrine (peak, 4.0 +/- 1.4 vs. 3.5 +/- 0.8 nmol/l [P = 0.84]; threshold, 3.8 +/- 0.1 vs. 3.6 +/- 0.1 mmol/l glucose [P = 0.38]), water loss (peak, 194 +/- 34 vs. 179 +/- 47 g-1.m-2.h-1 [P = 0.73]; threshold, 2.9 +/- 0.2 vs. 2.9 +/- 0.2 mmol/l glucose [P = 0.90]), tremor (peak, 0.28 +/- 0.05 vs. 0.37 +/- 0.06 root mean square volts (RMS V) [P = 0.19]; threshold, 3.2 +/- 0.2 vs. 3.1 +/- 0.2 mmol/l glucose [P = 0.70]), total symptom scores (peak, 10.6 +/- 2.1 vs. 10.8 +/- 1.9 [P = 0.95]; threshold, 3.3 +/- 0.2 vs. 3.6 +/0 0.1 mmol/l glucose [P = 0.15]), and cognitive function (four-choice reaction time: threshold, 2.9 +/- 0.2 vs. 3.0 +/- 0.2 mmol/l glucose [P = 0.69]) were unaffected. CONCLUSIONS: The effect on hypoglycemic physiological responses of 2 h of experimental hypoglycemia lasts for 1-2 days in these patients with IDDM . The pathophysiological effect of antecedent hypoglycemia may be of shorter duration in IDDM patients, compared with nondiabetic subjects.

Adult↗
PubMed1997

Social support in critically ill adults: a replication.

This study was designed to increase understanding of social support from the viewpoint of the critically ill adults. The authors investigated what the critically ill adults described as supportive behaviors, as well as the source of those behaviors. Open-ended interviews with 10 patients yielded rich data, which are presented in the article as cases illustrating the extremes of emotional support from physicians, nurses, hospital staff, family, and friends. The themes derived from the data stress the positive feelings of the participants when they believe they are being supported and the negative feelings when the patients believe they are not supported.

Adult↗
PubMed1996

Similar physiological and symptomatic responses to sulphonylurea and insulin induced hypoglycaemia in normal subjects.

There is little information concerning the physiological response to hypoglycaemia induced by sulphonylureas. We compared the physiological and symptomatic responses to insulin and tolbutamide induced hypoglycaemia in 8 normal subjects. While infusing either insulin or tolbutamide, we used a glucose clamp to maintain blood glucose at 4.5 mmol l-1 for 30 min and lowered it to 2.9 mmol l-1 for a further 30 min. Mean peripheral insulin levels during the insulin infusion arm in comparison with the tolbutamide infusion were not significantly different during the euglycaemic plateau: 106 +/- 4 vs 77 +/- 15 mU l-1 (mean +/- SEM) (mean difference 29 mU l-1, 95% CI -22 to 80; p = NS) but were greater during the hypoglycaemic plateau: 106 +/- 3.5 vs 21.0 +/- 4.0 mU l-1 (mean difference 85 mU l-1, 95% CI 72 to 98; p < 0.0001). Portal insulin concentrations, calculated from C-peptide data were not significantly different during the euglycaemic plateau with insulin as compared to tolbutamide. However, during hypoglycaemia portal insulin concentrations were significantly higher 15 min from the start of the plateau, during insulin infusion. During hypoglycaemia induced by either insulin or tolbutamide there were similar peak responses of glucagon: 124 +/- 14 vs 128 +/- 7 ng l-1 (mean difference -4, 95% CI -39 to 31; p = NS) and adrenaline: 2.9 +/- 0.4 vs 2.8 +/- 0.3 nmol l-1, (mean difference 0.1, 95% CI -0.9 to 1.0; p = NS). Increases in tremor and sweating and deterioration in reaction time were similar during both periods of hypoglycaemia as were increases in total: 18.5 +/- 1.4 vs 19.6 +/- 2.2 (mean difference -1.0, 95% CI -3.8 to 1.8; p = NS) and autonomic: 8.9 +/- 0.9 vs. 9.9 +/- 1.3 (mean difference -1.1, 95% CI -5.9 to 3.6; p = NS) symptom scores. We conclude that there is no difference in the glucagon, sympathoadrenal, cognitive or symptomatic response during hypoglycaemia induced by either insulin or tolbutamide. This suggests that the different insulin concentrations produced by these contrasting models of hypoglycaemia had no effect on the physiological response and patients taking sulphonylureas can be expected to develop similar warning symptoms to those on insulin.

Adult↗
PubMed1996

Synovial fluid and serum concentrations of aminoterminal propeptide of type III procollagen in healthy volunteers and patients with joint disease.

OBJECTIVES: To analyse synovial fluid and serum concentrations of the amino-propeptide of the type III procollagen (PIIINP) in normal individuals and patients with joint disease, and to explore the relationship between synovial fluid PIIINP concentrations and the rheumatological diagnosis, local inflammation, and joint disease. METHODS: A radioimmunoassay was used to measure the PIIINP concentrations in serum and knee joint synovial fluid from 16 healthy volunteers and patients with osteoarthritis (OA) (n = 40), rheumatoid arthritis (RA) (n = 30), and psoriatic arthritis (PsA) (n = 12). The PIIINP measurements were related to demographic data, synovial fluid leucocyte counts, and radiographic changes at the knee. RESULTS: Serum PIIINP concentrations were greater in each of the disease groups than in control subjects, but there were no differences between the disease groups. Synovial fluid concentrations of PIIINP were much greater than those in serum, indicating local production, and were significantly greater in RA than in other disease groups (p < 0.001). There was only a weak positive correlation between synovial fluid leucocyte counts, some radiographic changes, and synovial fluid PIIINP concentrations. CONCLUSIONS: These data suggest that synovial fluid PIIINP concentrations may reflect local synovial proliferative processes in joint disease, and that they could be of diagnostic and prognostic value in inflammatory arthropathies.

Adult↗
PubMed1996

Prenatal diagnosis of Hb Bart's hydrops fetalis in West Malaysia: the identification of the alpha thal 1 defect by PCR based strategies.

Haemoglobin Bart's hydrops fetalis is the result of complete absence of functional alpha-globin genes where the fetus is homozygous for the alpha 0-thal gene. Prenatal diagnosis can be made by analysis of fetal DNA from chorionic villus, amniotic cells and fetal blood. Earlier studies for analysing genomic DNA needed digestion with restriction enzymes and hybridisation to radiolabelled probes which took 2 weeks. We have used the polymerase chain reaction (PCR) and non-radioactive primers to identify specific target sequences with results available within 1-3 days for the diagnosis of haemoglobin Bart's syndrome. With fetal blood samples, complete absence of alpha-chain synthesis is confirmed by globin chain electrophoresis on cellulose acetate pH 6.0.

Base Sequence↗
PubMed1995

Correlation between synovial fluid markers of cartilage and bone turnover and scintigraphic scan abnormalities in osteoarthritis of the knee.

OBJECTIVE: To test the hypothesis that scintigraphic evidence of bone activity will correlate with biochemical evidence of increased matrix turnover in osteoarthritis (OA). METHODS: Keratan sulfate epitope (5D4), chondroitin sulfate epitope (3B3), and osteocalcin (OC) were measured in synovial fluid (SF) from 35 patients with knee OA, within 1 month of bone scan. RESULTS: SF OC levels correlated with 5D4 levels (r = 0.32, P = 0.047) and with abnormalities on scintigraphic scan. Mean OC levels were 47% higher (P = 0.016) in patients with severely abnormal findings on scans compared with levels in patients with mildly abnormal scan findings. No significant association of 5D4 or 3B3 levels and perfusion- or late (bone)-phase scintigraphic abnormalities was found. CONCLUSION: These data support the hypothesis that there is an association between late-phase bone scan abnormalities and SF biochemical markers of bone turnover in OA.

Aged↗
PubMed1995

Serum hyaluronic acid level as a predictor of disease progression in osteoarthritis of the knee.

OBJECTIVE: To investigate the prognostic value of serum hyaluronic acid (HA) and keratan sulfate (KS) levels in relation to tibiofemoral osteoarthritis (OA) of the knee. METHODS: Clinical and demographic data were collected on 94 patients. Radiographs were obtained at study entry and at 5-year followup. Disease progression was defined as 2 mm of joint space narrowing of any tibiofemoral compartment, and/or knee joint surgery during the study period. Serum HA and KS were measured and levels were correlated with entry data and disease progression. RESULTS: At entry, HA levels were significantly related to disease duration (P = 0.036), minimum joint space (P = 0.049), and previous surgery (P = 0.001). After these variables were taken into account, patients whose disease had progressed were shown to have had significantly higher levels of HA at baseline compared with those whose disease had not progressed (P = 0.019). However, there were no significant differences in levels of serum KS between those with and those without disease progression, at entry (P = 0.779) or at subsequent visits. CONCLUSION: These results suggest that serum HA levels predict disease outcome in OA of the knee and confirm that a single measurement of the serum level of KS is not useful as a prognostic marker in OA.

Age Factors↗
PubMed1995

Prolonged but partial impairment of the hypoglycaemic physiological response following short-term hypoglycaemia in normal subjects.

Recent studies have reported reduced endocrine and symptomatic responses to hypoglycaemia 18-24 h after antecedent hypoglycaemia in both non-diabetic subjects and those with insulin-dependent diabetes mellitus. We examined these and peripheral physiological responses in eight non-diabetic subjects aged 23-35 years in the week following antecedent hypoglycaemia. Blood glucose levels were held at plateaus of 5 mmol/l and 2.5 mmol/l for 30 min during hyperinsulinaemic (60 mU x m-2x min-1) morning clamps on days 1, 3 and 8 of two study periods separated by at least 4 weeks. Measurements were made at time 0, 15 and 30 min of each plateau on each day. One the afternoon of Day 1 we also induced either euglycaemia with a blood glucose level of 5 mmol/l (control week) or hypoglycaemia of 2.9 mmol/l (hypo week) for 2 h in random order. The adrenaline response to morning hypoglycaemia (p<0.001 on all days) was attenuated on Day 3 (p<0.05) and Day 8 (p<0.05) compared to Day 1 of hypo week only. Sweating was also attenuated on Day 3 (p<0.05) and Day 8 (p<0.02) of hypo week only. Noradrenaline levels and tremor increased during hypoglycaemia on each study day (p<0.05) but did not differ between days in either week. During hypo week only, the total symptom score response to hypoglycaemia was attenuated on Day 3 (p<0.03) but not Day 8 (p=0.10). Autonomic symptoms were similarly affected. In summary, the physiological responses to hypoglycaemia are affected differentially by antecedent hypoglycaemia with sweating and adrenaline responses remaining impaired for at least adrenaline responses remaining impaired for at least 5 days.

Adult↗
PubMed1995

Vernix caseosa peritonitis. An infrequent complication of cesarean section with distinctive histopathologic features.

The authors report two cases of vernix caseosa peritonitis, an infrequent complication of cesarean section with distinctive histopathologic findings. Both patients underwent exploratory laparotomy for unexplained abdominal pain after cesarean section. Histopathologic evaluation of surgically removed tissue revealed an organizing peritonitis, which included prominent collections of anucleate squamous cells in association with a foreign body-type granulomatous response. In both cases, the surgical pathologist suggested that the abdominal pain was likely a result of peritoneal reaction to spillage of keratinous material (vernix caseosa) derived from amniotic fluid contents during cesarean section. Surgical pathologists should be aware of this entity and include it in the differential diagnosis of acute abdominal pain.

Abdominal Pain↗
PubMed1995

Malignant mixed müllerian tumor versus high-grade endometrial carcinoma and aggressive variants of endometrial carcinoma: a comparative analysis of survival.

To ascertain whether uterine malignant mixed müllerian tumors are biologically distinct from high-grade endometrial carcinomas (FIGO grade 3), we compared patient survival in 32 and 39 cases, respectively. The Cox proportional hazard model was employed to determine whether tumor type was an independent predictor of survival. The survival of patients with MMMT was also compared to that of patients with serous adenocarcinoma and clear cell carcinoma. The 5-year overall and disease-free survival were significantly lower for malignant mixed müllerian tumors (25% and 11%) than for high-grade endometrial carcinomas (64% and 56%). Using the Cox proportional hazard model, tumor type (MMMT vs. high-grade endometrial carcinoma) was a statistically significant predictor of survival after other important prognostic variables such as pathologic stage, depth of myometrial invasion, and vascular invasion had been taken into account. The increased aggressiveness of MMMT appears most attributable to their tendency to reach a more advanced stage by the time of clinical presentation and to their greater propensity for upper abdominal dissemination. The survival of patients with MMMT was also lower than that of patients with the special histologic variants of endometrial carcinoma, serous adenocarcinoma and clear cell carcinoma, which are recognized for their unusually aggressive clinical behavior. These results indicate that uterine malignant mixed müllerian tumors are clinically more aggressive than high-grade endometrial carcinomas and should continue to be recognized as a distinct entity.

Adenocarcinoma, Clear Cell↗
PubMed1995

The clinical severity of beta-thalassemia mutations in West Malaysia.

Beta-thalassemia in West Malaysia is caused by 14 molecular defects with differing clinical severity. In Chinese patients from West Malaysia, the main beta-thalassemia mutations seen were (a) a 4 base pair-TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)]; (b) a C to T substitution at the second intervening sequence (IVS2-654); (c) an A to G substitution in the TATA box [-28 (A to G)], and (d) an A to T substitution in codon 17[17 A to T]. In the Malays, the main mutations seen were (a) a G to C in nucleotide 5 at the intervening sequence I [IVS1-5 (G to C)]; (b) G to T substitution in nucleotide I at the intervening sequence I [IVS1-1 (G to T)]; (c) a A to T substitution in codon 17 (17 A to T); (d) removal of C from codon 35 [codon 35 (-C)], and (e) a 4 base pairs-TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)]. A scoring system (Tha1 CS) has been formulated to predict clinical severity. It is the type of beta-thalassemia mutation present that decides on the clinical phenotype. The most severe beta-thalassemia mutation is assigned a score of 4. A score of 8 indicates severe thalassemia.

China↗
PubMed1994

Arthritis or arteritis.

Diagnosing Polymyalgia Rheumatica (PMR) or Giant Cell Arthritis (GCA) on an established background of arthritis is fraught with difficulties. We describe one such case.

Aged↗
PubMed1994

Expression of p53, transforming growth factor alpha, epidermal growth factor receptor, and c-erbB-2 in endometrial carcinoma and correlation with survival and known predictors of survival.

Abnormal expression of p53, transforming growth factor alpha (TGF alpha), epidermal growth factor receptor (EGFR), and c-erbB-2 occurs in a variety of cancers and in some cases is associated with poor prognosis. Immunoperoxidase staining using these markers in formalin-fixed, paraffin-embedded endometrial carcinoma tissue was performed to determine whether immunoreactivity correlates with survival and known prognostic variables. Cases included 84 endometrioid adenocarcinomas, five adenoacanthomas, 12 adenosquamous carcinomas, 11 serous carcinomas, 15 clear cell carcinomas, and one carcinosarcoma for a total of 128 cases. Frequencies of immunoreactivity were as follows: p53, 37 of 128 (29%); TGF alpha, strong (2+) 23 of 128 (18%) and intermediate (1+) 26 of 128 (20%); EGFR, strong (3+) 21 of 128 (16%) and intermediate (2+ or 1+) 83 of 128 (65%); and c-erbB-2, strong (2+) four of 128 (2%) and intermediate (1+) three of 128 (1%). p53 and TGF alpha staining showed statistically significant correlations with decreased length of survival (P < .0017 and P < .0013, respectively, generalized Savage [Mantel Cox]). p53 immunoreactivity correlated with tumor types, grade, and stage. Transforming growth factor alpha staining correlated with increased depth of invasion and presence of vascular invasion. Epidermal growth factor receptor staining did not correlate with length of survival or known prognostic variables. c-erbB-2 staining correlated with tumor type. In the multivariate analysis p53 and TGF alpha staining were not independent predictors of survival when other variables were taken into account, including grade, stage, tumor type, presence of vascular invasion, and depth of invasion. Grade and stage were the only independent predictors of survival when used in combination in a Cox proportional hazards model.

Biomarkers, Tumor↗
PubMed1994

Intra-articular hyaluronic acid in osteoarthritis of the knee: an investigation into mechanisms of action.

The objective of this study was to investigate mechanisms of action of intra-articular hyaluronic acid in osteoarthritis (OA) of the knee. Twelve patients with bilateral knee OA and synovial effusions entered a randomized, single-blind, blind observer study. Hyaluronic acid ("Hyalgan", Fidia SpA, Italy) or placebo were given by intra-articular injection weekly for 5 weeks. Assessments included clinical indices and imaging (magnetic resonance imaging (MRI) and 99m Tc bone scanning) before and after the course of injections. In addition, synovial fluid keratan sulfate (KS), chondroitin sulfate (CS) and C-propeptide of type II collagen (CPII) were measured. MRI and 99m Tc scanning showed no change in either treated or placebo knees over the 6-week study period. A fall in KS levels occurred in treated knees compared with placebo (Wilcoxon paired test, P = 0.1), although this did not reach significance perhaps due to small sample numbers). Ten out of 12 treated knees showed a fall in KS, compared with four out of 12 placebo knees. CS and CPII levels did not change significantly. Intra-articular injection of hyaluronic acid did not result in any improvement in the clinical indices compared to the placebo. In conclusion, assessment of cartilage markers may be of value when studying novel therapies in OA. MRI appearances remain remarkably stable over a 6-week period.

Adjuvants, Immunologic↗
PubMed1994

Acute inflammatory polyarthritis in association with tamoxifen.

The antioestrogen drug tamoxifen is widely used to treat breast carcinoma. We report three cases in which its use was temporally related to the development of an acute inflammatory polyarthritis resembling RA; a side-effect not previously reported. Possible mechanisms for such an effect are discussed.

Acute Disease↗