Steady-state PERG adaptation: a conspicuous component of response variability with clinical significance.

PURPOSE: To investigate within-test variability of the steady-state PERG (SS-PERG). METHODS: SS-PERGs were recorded in response to black-white horizontal gratings (1.6 cycles/deg, 98% contrast, 15.63 reversals/s, LED display, 25 deg square field, 800 cd/sqm mean luminance) using skin electrodes. PERG and noise (± reference) signals were averaged over 1024 epochs (~ 2.2 min) and Fourier analyzed to retrieve SS-PERG amplitude and phase. SS-PERGs were split into 16 partial averages (samples) of 64 epochs each, and corresponding amplitudes and phases combined in polar coordinates to assess their dispersion (within-test variability). To assess time-dependent variability, samples were clustered in four successive time segments of ~ 33 s each. Amplitude adaptation was defined as amplitude difference between initial and final clusters, and PERG phase adaptation as the corresponding phase difference. To determine the dynamic range of SS-PERG adaptation, recording was performed in normal controls of different age (n = 32) and patients with different severity of optic nerve dysfunction (early manifest glaucoma, EMG, n = 7; non-arteritic ischemic optic neuropathy, NAION, n = 5). RESULTS: Amplitude adaptation was largest in younger controls (amplitude adaptation ÷ noise, SNR = 9.5, 95% CI 13.1, 5.9) and progressively decreased with increasing age (older subjects, SNR = 5.5, 95% CI 9.2, 1.8) and presence of disease (EMG: SNR = 2.4, 95% CI 3.5, 1.4; NAION: SNR = 1.9, 95% CI 6.5,-2.2). In 11 young subjects, amplitude adaptation was repeatable (test-retest in two sessions a week apart; intraclass correlation coefficient = 0.59). Phase adaptation was not significantly different from zero in all groups. CONCLUSIONS: SS-PERG adaptation accounts for a sizeable portion of the within-test variability. As it has robust SNR, sufficient test-retest variability, and is altered in disease, it may have physiological and clinical significance. This study suggests that SS-PERG protocols should include adaptation in addition to SS-PERG amplitude and phase/latency.

Carotid-cavernous fistula: current concepts in aetiology, investigation, and management.

A carotid-cavernous fistula (CCF) is an abnormal communication between arteries and veins within the cavernous sinus and may be classified as either direct or dural. Direct CCFs are characterized by a direct connection between the internal carotid artery (ICA) and the cavernous sinus, whereas dural CCFs result from an indirect connection involving cavernous arterial branches and the cavernous sinus. Direct CCFs frequently are traumatic in origin and also may be caused by rupture of an ICA aneurysm within the cavernous sinus, Ehlers-Danlos syndrome type IV, or iatrogenic intervention. Causes of dural CCFs include hypertension, fibromuscular dysplasia, Ehlers-Danlos type IV, and dissection of the ICA. Evaluation of a suspected CCF often involves non-invasive imaging techniques, including standard tonometry, pneumotonometry, ultrasound, computed tomographic scanning and angiography, and/or magnetic resonance imaging and angiography, but the gold standard for classification and diagnosis remains digital subtraction angiography. When a direct CCF is confirmed, first-line treatment is endovascular intervention, which may be accomplished using detachable balloons, coils, liquid embolic agents, or a combination of these tools. As dural CCFs often resolve spontaneously, low-risk cases may be managed conservatively. When invasive treatment is warranted, endovascular intervention or stereotactic radiosurgery may be performed. Modern endovascular techniques offer the ability to successfully treat CCFs with a low morbidity and virtually no mortality.

Influence of landmark and surgical variability on virtual assessment of total knee arthroplasty.

Given advances in recent years in imaging modalities and computational hardware/software, virtual analyses are increasingly valuable and practical for evaluating total knee arthroplasty (TKA). However, the influence of variabilities at each step in computational analyses on predictions of TKA performance for a population has not yet been thoroughly investigated, nor the relationship between these variabilities and expected variations in surgical practice. Understanding these influences is nevertheless essential for ensuring the clinical relevance of theoretical predictions. Here, a morphological analysis of proximal tibial resections within TKA is proposed and investigated. The goals of this analysis are to quantify the influence of variability in landmark detection on resection parameters and to evaluate this sensitivity relative to expected clinical variability in TKA resections. Results here are directly applicable to population-level computational analyses of morphological and functional TKA performance.

Preparing feminist facilitators. Assisting abused women in transitional or support-group settings.

This article has reviewed one approach to the preparation of support group facilitators to enable them to better meet the needs of abused women. Those women may still be in abusive relationships or they may have left one; they may be unsure whether they are abused; or they may be seeking practical suggestions about ways to tackle a particular problem. Whatever their specific situations, they can benefit from a supportive, accepting, and safe environment in which to explore their options.

Dyslipidaemia is associated with insulin resistance in women with polycystic ovaries.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is characterized by hyperinsulinaemia and insulin resistance. Previous reports of lipid abnormalities in the syndrome have produced conflicting results which may, in part, be related to the lack of appropriate controls for the obese women with PCOS. Only one study has related lipid levels to insulin sensitivity. The objective of this study was to assess lipids and lipoproteins in women with PCOS, to compare the results with weight matched controls, and to relate the findings to indices of insulin secretion and action, and to menstrual history. DESIGN: A cross-sectional study of insulin sensitivity and lipids in a cohort of PCO subjects compared to weight and ethnic group matched controls. PATIENTS AND METHODS: We have therefore investigated glucose tolerance, plasma lipids and lipoproteins in 19 lean (LP) and 55 obese (OP) patients with PCO and compared the results with those in 22 lean (LC) and 15 obese (OC) control women. Insulin sensitivity was measured in the same subjects with a short insulin (0.05 U/kg i.v. insulin) tolerance test (LP, n = 18; OP, n = 20; LC, n = 19; OC, n = 11). RESULTS: Results are expressed as mean +/- SEM or median (interquartile range). Fasting plasma glucose levels were similar in the four groups but the plasma glucose area was higher after oral glucose (75 g) in both the lean and obese PCOS groups than in their controls (LC 32.4 +/- 0.7 vs LP 35.2 +/- 1.2, P < 0.01; OC 34.7 +/- 1.8 vs OP 37.8 +/- 1.5 mmol/l/3 h, P < 0.01). Insulin sensitivity was significantly reduced in obese PCOS women (LC 196 +/- 9 vs LP 179 +/- 9, NS; OC 168 +/- 12 vs OP 133 +/- 9 mmol/l/min, P < 0.01). Total serum cholesterol levels were similar in the four groups but HDL2-cholesterol was reduced in both obese and lean PCOS (LC 0.42 (0.38-0.62), LP 0.31 (0.26-0.44), P < 0.05; OC 0.34 (0.21-0.47), OP 0.21 (0.12-0.32) mmol/l, P < 0.01). Total HDL-cholesterol was decreased significantly only in the obese PCOS group. Body mass index correlated significantly and negatively with total HDL-cholesterol and with HDL2-cholesterol levels both within the PCOS group and the control women. Using multiple regression insulin insensitivity contributes significantly beyond BMI to the low HDL-cholesterol in women with polycystic ovaries. CONCLUSION: Polycystic ovary syndrome is associated with biochemical risk factors for premature vascular disease, which cannot be explained by obesity alone.

Enhancing nurses' effectiveness with abused women. Awareness, reframing, support, education.

Abuse against women, with its potential to affect every aspect of a woman's health and well-being, as well as the health and future of her children, is a reality that should be intolerable. Nurses are uniquely suited to address the needs of abused women because of their focus on holistic care and their advocacy role. Additionally, some abused women may find it easier to trust nurses simply because most nurses are women. To feel comfortable when working with abused women, nurses require various kinds of support. They need the support of the institutions in which they work so that they can undertake their work from a firm base. They need support from their professional associations so that they can be assured that all nurses are operating under the same obligation to the client. Lastly, they need the kind of support that comes from being prepared by their education, not only to understand, but also to provide holistic nursing care to abused women. It is unreasonable to expect front-line workers to undertake a task that is so clearly value-laden without the onset support of their educational institution, their facility's administration, and their professional associations. These are the bodies that should be expected to set the agenda to provide leadership. It is only when nurses have this firm base of support that they will be at ease with their role and feel able to intervene consistently and effectively. There is a growing body of knowledge on why nursing care to abused women is only sporadically delivered and frequently ineffective at present. Some reasons for this can be identified at the level of the individual nurse. It is, however, time for the educational, institutional, and professional levels to provide leadership. Nurses should and can be the most effective professionals working with abused women.

The effects of glibenclamide on glucose homeostasis and lipoprotein metabolism in poorly controlled type 2 diabetes.

Six patients with type 2 diabetes underwent detailed metabolic studies before and after a minimum of 3 months' glibenclamide therapy. Treatment was associated with a small but significant increase in body weight. Despite improvements in almost all the measured parameters of glucose homeostasis (plasma glucose, glycosylated haemoglobin (HbA1), hepatic glucose production and insulin-mediated glucose disposal) neither fasting serum triglycerides nor HDL cholesterol changed and apoprotein A1 concentrations actually decreased significantly. NEFA and glycerol in fasting plasma and during the clamp studies did not change significantly with treatment. Post-heparin lipoprotein lipase and hepatic lipase activity did not change significantly. Thus, despite substantial improvements in glycaemic control and insulin sensitivity with sulphonylurea therapy, several aspects of lipid and lipoprotein metabolism remain largely unaffected. This small study suggests either that lipoprotein concentrations in type 2 diabetes are not influenced by insulin sensitivity or that the improvement is offset by another change that occurs during this form of therapy. It also suggests that other forms of therapy will be required to improve these cardiovascular risk factors in type 2 diabetes.

Hepatic and lipoprotein lipases selectively assayed in postheparin plasma.

Sensitive, reliable procedures are reported for the selective assay of lipoprotein lipase (LPL) and hepatic lipase (HL) in postheparin plasma samples. LPL is inhibited in the HL assay by inclusion of 0.76 mol/L sodium chloride in the substrate. In the LPL assay, specificity is attained by pretreating the sample with sodium dodecyl sulfate, which selectively denatures HL. This LPL method was validated by direct comparison with a procedure in which HL is inactivated by an antiserum to human HL. We used the described assays to quantify LPL and HL activity in 32 normal adults, demonstrating a clear sex difference for both enzymes. On average, the men displayed higher HL and lower LPL activities than did the women.

Witnessing family violence: the children's experience.

A phenomenological study was conducted in order to describe the experience of children as they accompany their mothers who are leaving abusive relationships. Thirteen children were interviewed. The children describe their experience as having three components: living with violence, living in transition and living with Mom. Themes within these components are identified, and implications for nursing practice are discussed.

The response of hepatic lipase and serum lipoproteins to acute hyperinsulinaemia in type 2 diabetes.

Hepatic lipase has a putative role in the catabolism of HDL particles and, while its activity is dependent upon insulin in the rat, no such insulin responsiveness has been demonstrated in man. We studied 21 patients with type 2 diabetes to examine whether hepatic lipase activity was influenced by hyperinsulinaemia during a 2-4 h isoglycaemic clamp study. Acute changes in lipids, lipoproteins and apolipoproteins were also documented in pre- and post-clamp serum. Hepatic lipase activity during hyperinsulinaemia was compared with activity measured after an equivalent period without insulin. For comparison, nine non-diabetic subjects (matched for age and body mass index) underwent similar clamp studies. In the control experiment without insulin, hepatic lipase activity did not change significantly (mean 9.7 (range 2.3-22.3) in the morning and 9.9 (3.0-22.5) mmol h-1 l-1 in the afternoon, NS). In contrast, after the hyperinsulinaemic clamp, hepatic lipase activity fell significantly in diabetic subjects from 12.8 (4.4-30.6) to 10.4 (3.3-31.3) mmol h-1 l-1, P less than 0.0002 along with serum triglycerides and total and LDL cholesterol. The change in hepatic lipase activity was positively related to the fasting apoprotein B concentration (Spearman r = 0.54, P = 0.016). In the normal subjects, a similar decline in hepatic lipase activity was observed during hyperinsulinaemia (from 15.1 (9.8-32.7) to 12.6 (6.3-28.3) mmol h-1 l-1, P less than 0.01) along with decreases in total, HDL and LDL cholesterol, triglycerides and apoproteins A1 and B.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of insulin insensitivity and hepatic lipase in the dyslipidaemia of type 2 diabetes.

Fourteen male patients with Type 2 diabetes were studied to identify relationships between insulin-mediated glucose disposal, basal and glucose-stimulated insulin secretion, fasting lipoproteins and apolipoproteins, and the activities of lipoprotein lipase and hepatic lipase. Sensitivity of glucose disposal to exogenous insulin correlated positively with HDL-cholesterol (r = 0.65, p less than 0.05), HDL2-cholesterol (r = 0.59, p less than 0.05), and apolipoprotein A1 (r = 0.57, p less than 0.05) and negatively with apolipoprotein B (r = -0.53, p less than 0.05) and total: HDL-cholesterol ratio (r = -0.68, p less than 0.01). Fasting C-peptide correlated negatively with HDL-cholesterol (r = -0.76, p less than 0.01), HDL2-cholesterol (r = -0.80, p less than 0.001) and apoprotein A1 (r = -0.56, p less than 0.05) and positively with total: HDL-cholesterol ratio (r = 0.64, p less than 0.05). Neither fasting plasma glucose nor the indices of stimulated insulin secretion (glucose-stimulated plasma insulin and C-peptide) were related to any of the lipoprotein measures. Insulin insensitivity and hyperinsulinaemia were both associated with higher levels of hepatic lipase activity but did not influence lipoprotein lipase activity. In multiple linear regression analysis, hepatic lipase activity was related to HDL-cholesterol independent of insulin insensitivity. In addition, fasting C-peptide alone accounted for 70% of the variance in hepatic lipase activity and this was independent of insulin sensitivity and body mass index. We propose that the abnormalities of HDL-cholesterol in Type 2 diabetes are closely related to enhanced hepatic lipase activity brought about by increased insulin secretion which, in turn, is secondary to the defect in insulin action.

The influence of regional adiposity on atherogenic risk factors in men and women with type 2 diabetes.

To determine firstly whether body fat distribution could predict the presence of atherogenic risk factors better than overall adiposity in Type 2 diabetes, and secondly whether sex differences in these risk factors could be explained by sex differences in fat distribution, waist-to-hip girth ratio (WHR), serum lipids, lipoproteins, apolipoproteins, plasma lipolytic activity, and blood pressure were assessed in 47 patients with Type 2 diabetes, 21 women matched for age, body mass index (BMI) and blood glucose control with 26 men. The men had higher WHR (0.95 (range 0.83-1.07) vs 0.82 (0.74-0.94), p less than 0.001), lower HDL-cholesterol (1.03 +/- 0.05 vs 1.38 +/- 0.06 mmol l-1, p less than 0.001) and apolipoprotein A1 (1.40 +/- 0.06 vs 1.76 +/- 0.06 gl-1, p less than 0.001) concentrations, and higher hepatic lipase activities (16.2 (6.4-38.0) vs 8.6 (2.3-23.1) mmol h-1 l-1, p less than 0.01). In both men and women, BMI and WHR were positively related to serum triglyceride, insulin and C-peptide concentrations. In women, HDL-cholesterol was negatively related to BMI (r = -0.45, p less than 0.05) but only possibly related to WHR (r = -0.33, NS). In men, by contrast, WHR was related negatively to HDL-cholesterol (r = -0.60, p less than 0.005), HDL2-cholesterol (r = -0.43, p less than 0.05), and apolipoprotein A1 (r = -0.70, p less than 0.001) and positively to hepatic lipase activity (r = 0.65, p less than 0.001), whereas the same relationships with BMI were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of mild fasting hypertriglyceridaemia in non-insulin-dependent diabetes.

Factors contributing to fasting hypertriglyceridaemia were studied in 20 patients with non-insulin-dependent diabetes--nine with normal triglyceride concentrations [fasting triglyceride 0.94 (range 0.58-1.23) mmol l-1] and eleven with mild fasting hypertriglyceridaemia [fasting triglyceride 2.4 (1.82-4.0) mmol l-1]. The patients with hypertriglyceridaemia were more obese [body mass index 29.0 (24.6-33.8) vs. 25.7 (21.9-30.1) kg m-2, P less than 0.05] and demonstrated impaired glucose disposal in response to exogenous insulin at isoglycaemia [insulin sensitivity index, SIp 0.7 (0.27-2.5) vs. 2.4 (0.62-5.1) ml m-2 min per mU l-1, P less than 0.001]. Basal non-esterified fatty acid (NEFA) and glycerol concentrations were higher and were suppressed to a lesser extent during isoglycaemic hyperinsulinaemia. Fasting glucose and apolipoprotein B concentrations were higher in the hypertriglyceridaemic patients, but lipoprotein lipase activities were similar in the two groups. When the effect of obesity was removed (by weight-matching six normotriglyceridaemic with seven hypertriglyceridaemic patients) basal NEFA and glycerol concentrations and the suppression of NEFA in response to insulin remained significantly different between the two groups. We propose that defects in both the glucoregulatory and antilipolytic actions of insulin contribute to mild fasting hypertriglyceridaemia in NIDDM, and that these defects cannot be attributed solely to obesity. These disorders of insulin action may also have important implications for the postprandial metabolism of triglyceride-rich lipoproteins and hence atherogenesis.

The experiences of new fathers during the first 3 weeks of life.

Research has consistently demonstrated that the transition to parenthood is a stressful event. As well, the literature recognizes that the role of the father in North American society is in the process of change. The purpose of this qualitative study was to clarify our understanding of the experience of new fathers during the first 3 weeks postpartum. Twenty-two fathers were interviewed in their homes using a semi-structured interview format. Findings suggest that new fathers go through a predictable three-stage process during the transition to fatherhood. In addition, factors were identified which affect the transition. Nursing interventions were suggested to facilitate this process and implications for future study included.

Alpha-blocker therapy; a possible advance in the treatment of diabetic hypertension--results of a cross-over study of doxazosin and atenolol monotherapy in hypertensive non-insulin dependent diabetic subjects.

Hyperglycaemia, a raised fibrinogen, an increased serum triglyceride and a reduced HDL-cholesterol are common metabolic features of non-insulin dependent diabetes mellitus (NIDDM). Hypertension is frequently associated with NIDDM, however the influence of antihypertensive therapy on these combined factors in the diabetic is at present unclear. In a double-blind placebo-controlled crossover study in 20 stable NIDDM subjects with hypertension, the metabolic effects of 6 weeks' treatment with the alpha-blocker, doxazosin, was compared with treatment with the beta-blocker, atenolol. Similar and significant reductions in BP were produced by both drugs. Significant increases in weight, HbA1, apoprotein B, serum triglyceride and cholesterol/HDL ratio were observed with atenolol therapy. Doxazosin therapy was associated with opposite patterns of changes in fasting glucose, lipids and lipoproteins but only for serum triglyceride was difference between treatments significant. Fibrinogen was not altered by either treatment. Conclusions from this study indicate; 1) adrenergic mechanisms may be an important influence on glucose homeostasis and lipid metabolism in NIDDM and 2) the beta-blocker, atenolol, has a small adverse effect on weight, glycaemic control and the atherogenic lipid profile, whereas the alpha-blocker, doxazosin, has no such effect and may, in part, correct the disturbances of lipoprotein metabolism characteristic of NIDDM.

Use of social support in a transition house for abused women.

It is recognized that individuals with healthy support systems withstand stress and crisis better than those without such support. The way in which support is used has not been specified. Using data gathered during interviews with eight women who had recently spent time in a transition house, a framework for a process of use of social support is discussed. This framework was developed using a phenomenological approach. In the framework can be found four stages that an individual passes through in using social support. Each stage is defined by a need to be met and an action the individual takes in attempting to meet that need. The specific implications for those working with clients in each of the four stages are discussed and difficulties that might occur in working with a group of clients, each at a different point in the process, are identified.