Clinical experience over 48 years with pheochromocytoma

OBJECTIVE

To analyze the presentation, localization, surgical management, pathology, and long-term outcome of a large series of patients with pheochromocytomas.

SUMMARY BACKGROUND DATA

There are several areas of controversy pertaining to pheochromocytomas. Although many studies report a higher rate of malignancy for extraadrenal pheochromocytomas than for adrenal pheochromocytomas, the number of patients with the former tumor are small and statistical analysis is lacking. There has also been recent debate as to whether microscopic features of the tumor may be predictive of future behavior.

METHODS

From 1950 to 1998, the authors observed 108 pheochromocytomas in 104 patients. The outcome of these patients has been followed prospectively. The medical records of these patients were reviewed for data on the presentation, localization, surgical management, pathology, and outcome. Patient survival was analyzed using Kaplan-Meier survival distributions.

RESULTS

This study included 66 female patients and 38 male patients. The average age at surgery was 42.3 years. Sporadic cases accounted for 84% of the patients; the other 16% had multiple endocrine neoplasia type 2, von Recklinghausen's disease, von Hippel-Lindau disease, or Carney's syndrome. Of 64 adrenal tumors, 55 were initially considered benign, 6 had microscopic malignant features, and 3 had malignant disease. Mean patient follow-up was 12.6 years. To date, in five additional patients (none with microscopic disease) malignant disease developed (13% overall rate of malignancy). Recurrence occurred as late as 15 years after resection. Of 26 extraadrenal pheochromocytomas, 14 were initially considered benign, 8 had microscopic malignant features, and 4 had malignant disease. Thus, 46% of patients had either malignant disease or tumors with malignant features. Mean patient follow-up was 11.5 years. In one patient with benign disease and in one patient with malignant features, malignant disease developed (23% overall rate of malignancy). The difference in the rate of malignancy was not statistically significant between adrenal and extraadrenal pheochromocytomas. Patients with adrenal and extraadrenal pheochromocytomas also had similar rates of survival (p = NS).

CONCLUSIONS

The data suggest that patients with extraadrenal pheochromocytomas have the same risk of malignancy and the same overall survival as patients with adrenal pheochromocytomas. Lifelong follow-up of these patients is mandatory.

Synergism between neuropeptide Y and norepinephrine highlights sympathetic cotransmission: studies in rat arterial mesenteric bed with neuropeptide Y, analogs, and BIBP 3226

Although abundant literature supports the notion that neuropeptide Y (NPY) synergizes in vivo and in vitro, the vasomotor activity elicited by norepinephrine (NE), the converse interaction (i.e., the adrenergic modulation of the NPY vasomotor response) has been less characterized. To assess whether NE synergizes the vasomotor effect of NPY, the rat arterial mesenteric bed was chosen as a model experimental system. Mesenteries were precontracted with NE and few minutes later were perfused with exogenous NPY. Under these conditions, NPY contracted the arterial mesenteric bed with an EC50 value of 0.72 +/- 0.06 nM. NPY was unable to contract this vascular territory without an agonist-induced precontraction. Other agonists, such as endothelin-1, a synthetic analog of prostaglandin F2alpha, or 5-hydroxytryptamine, also were effective primers because in their presence, NPY was a potent vasoconstrictor. In contrast, mesenteries precontracted with KCl failed to evidence the NPY-induced rise in perfusion pressure. Two structural analogs of NPY, PYY and [Leu31, Pro34]NPY, mimicked the activity of NPY. The NPY fragment 13-36 did not elicit such a response. All NPY analogs exhibited less efficacy and potency relative to NPY. The NPY- and related structural analog-induced vasoconstriction was competitively and reversibly antagonized by BIBP 3226; the pA2 of the NPY interaction was 7.0. The application of 0.1 to 1 microM BIBP 3226 or 0.1 to 10 nM prazosin at the peak of the NPY vasomotor response elicited a gradual blockade of the vasoconstriction. Although BIBP 3226 blocked the increase in perfusion pressure elicited by NPY, leaving unaffected the NE-induced tone, 10 nM prazosin blocked the full response, including the NE-induced component. Tissue preincubation with 200 nM nifedipine abolished the NPY-induced vasoconstriction; likewise, the acute application of 10 to 100 nM nifedipine blocked gradually the maximal NPY-induced contraction. Removal of the mesenteric endothelial layer increased the potency of NPY by 2-fold; it also slightly potentiated the antagonist activity of BIBP 3226. The synergism between NPY and NE backs the principle of sympathetic cotransmission.

Relevance of clinical trial results in myocardial infarction to medical practice: comparison of four year outcome in participants of a thrombolytic trial, patients receiving routine thrombolysis, and those deemed ineligible for thrombolysis

OBJECTIVE

To assess the medium to long term outcome of patients ineligible for thrombolysis compared to those enrolled in a clinical trial of thrombolysis and patients receiving non-trial thrombolysis.

DESIGN

Cohort study based on the Nottingham heart attack register.

SETTING

Two district general hospitals serving a defined urban/rural population.

SUBJECTS

All patients admitted with a confirmed acute myocardial infarction during 1992 categorised as either participants of a thrombolytic trial (group A, n = 140), receiving non-trial thrombolysis (group B, n = 329), or deemed ineligible for lytic treatment (group C, n = 431).

MAIN OUTCOME MEASURES

Background characteristics, inhospital treatment, patterns of follow up, referrals to cardiologists, revascularisation rates, and short and long term survival.

RESULTS

Clinical trial recruits were younger by almost 10 years, were less likely to have a previous history of myocardial infarction, and more likely to be in Killip class 1 on admission than those ineligible for thrombolysis. Cardiology follow up was mandatory for all surviving trial participants but 22% of patients in group B and 31% of patients in group C received no follow up, and during four years less than 50% ever saw a cardiologist. Revascularisation was performed in 17.2% of patients in group A, 13.6% of patients in group B, and 7.5% of patients in group C. Cumulative mortality at a median of four years was 24.3% in group A, 36.8% in B, and 59.6% in group C. Adjusting for age, sex, previous myocardial infarction, type of infarction, and Killip class in a logistic regression model the odds ratios (OR) of death at four years for groups B and C were 1.60 (95% confidence intervals (CI) 0.97 to 2.63, p = 0.065) and 2.64 (95% CI 1.61 to 4. 32, p < 0.001), respectively, when compared to group A (OR 1).

CONCLUSIONS

Patients enrolled into thrombolytic trials are at low risk. Patients deemed ineligible for thrombolysis are high risk, receive less surveillance, are less likely to be revascularised or receive trial proven treatments, have a poor long term outcome not entirely explained by increased age or severity of infarction, and deserve further evaluation.

Multicenter study of lamivudine therapy for hepatitis B after liver transplantation. Lamivudine Transplant Group

Hepatitis B after liver transplantation is often fatal, and no proven medical therapy exists for this condition. We chose to study the potential efficacy of lamivudine therapy for patients with chronic hepatitis B after liver transplantation. Fifty-two patients with chronic hepatitis B after liver transplantation were treated in an open label, multicenter study. Each had detectable hepatitis B virus (HBV) DNA in serum and 45 (87%) had detectable serum hepatitis B e antigen before treatment. Patients were treated for 52 weeks with lamivudine (100 mg daily). The primary endpoint was undetectability of HBV DNA; secondary endpoints included normalization of serum alanine transaminase (ALT) levels, disappearance of hepatitis B e antigen, and improvement in liver histology. After treatment, 60% of patients had undetectable HBV DNA by solution hybridization assay, 14 (31%) of the initially positive patients lost hepatitis B e antigen; hepatitis B surface antigen was undetectable in 3 (6%); and serum ALT levels normalized in 71%. Blinded histological assessments showed improvement in the histological activity index (P =.007 for periportal necrosis,.001 for lobular necrosis, and.013 for portal inflammation). YMDD variants of HBV, potentially associated with drug resistance, were detected in 14 (27%) of the patients. Repeat liver biopsies in 7 patients with the mutated virus were unchanged in 2, improved in 2, and worse in 3. We conclude that lamivudine is a potentially effective therapy for hepatitis B after liver transplantation.

COX-2 compensation in the uterus of COX-1 deficient mice during the pre-implantation period

Prostaglandins (PGs) produced by cyclooxygenase (COX) participate in many aspects of female reproduction. The two isoforms of cyclooxygenase, COX-1 and COX-2, have distinct expression patterns in the mouse uterus during the peri-implantation period and suggest their independent contribution to uterine PGs. Using wild type and COX-1(-/-) mice, we examined the role of COX-1-derived PGs on day 4 of pregnancy, when its expression is maximal. Uterine vascular permeability was measured by 125I-labeled bovine serum albumin (BSA) uptake, and PG content was measured by gas chromatography-mass spectrometry. Vascular permeability and PG concentrations were reduced in COX-1(-/-) mice, but by less than the expected amount. After ovariectomy, uterine vascular permeability declined in both groups, but returned to baseline in wild type and was exaggerated in COX-1(-/-) females after treatment with ovarian steroids. Most importantly, COX-1(-/-) uteri displayed COX-2 expression on the morning of day 4, when COX-2 is normally absent. This hybridization pattern resembles the native expression of COX-1, and may partially offset the loss of COX-1-derived PGs. These data indicate that COX-1-derived PGs are important during uterine preparation for implantation, and that COX-2 compensation occurs in the absence of COX-1.

Quality of life four years after acute myocardial infarction: short form 36 scores compared with a normal population

OBJECTIVES

To assess the impact of myocardial infarction on quality of life in four year survivors compared to data from "community norms", and to determine factors associated with a poor quality of life.

DESIGN

Cohort study based on the Nottingham heart attack register.

SETTING

Two district general hospitals serving a defined urban/rural population.

SUBJECTS

All patients admitted with acute myocardial infarction during 1992 and alive at a median of four years.

MAIN OUTCOME MEASURES

Short form 36 (SF 36) domain and overall scores.

RESULTS

Of 900 patients with an acute myocardial infarction in 1992, there were 476 patients alive and capable of responding to a questionnaire in 1997. The response rate was 424 (89. 1%). Compared to age and sex adjusted normative data, patients aged under 65 years exhibited impairment in all eight domains, the largest differences being in physical functioning (mean difference 20 points), role physical (mean difference 23 points), and general health (mean difference 19 points). In patients over 65 years mean domain scores were similar to community norms. Multiple regression analysis revealed that impaired quality of life was closely associated with inability to return to work through ill health, a need for coronary revascularisation, the use of anxiolytics, hypnotics or inhalers, the need for two or more angina drugs, a frequency of chest pain one or more times per week, and a Rose dyspnoea score of >/= 2.

CONCLUSIONS

The SF 36 provides valuable additional information for the practising clinician. Compared to community norms the greatest impact on quality of life is seen in patients of working age. Impaired quality of life was reported by patients unfit for work, those with angina and dyspnoea, patients with coexistent lung disease, and those with anxiety and sleep disturbances. Improving quality of life after myocardial infarction remains a challenge for physicians.

Health care costs associated with chronic hepatitis B

The long-term health care costs of patients with chronic hepatitis B (CHB) were compared with those of patients without CHB. Patients with laboratory markers for CHB were identified from an HMO database and matched with up to four control patients (either not tested for hepatitis B infection or with negative test results). Cost data were collected retrospectively for both groups of patients for the period up to 30 days before identification of the first marker for hepatitis B (prediagnosis), 30 days before identification of the first marker through 180 days after the identification (peridiagnosis), and 181 days after identification through the end of the six-year study period. Costs were categorized as emergency room, inpatient, short-stay inpatient, laboratory, radiology, office visit, pharmacy, outside claim, or other and were analyzed as ratios of the costs of each patient with CHB to the median of the corresponding control patients. Eighty-eight patients were identified as having CHB; there were 342 control patients. In the seven months surrounding the appearance of their first diagnostic marker, the patients with CHB had costs 3.3 times those of the corresponding control patients and, after the first seven months, 2.9 times those of the control patients per month. Peridiagnosis costs in the categories of laboratory, radiology, office visits, and pharmacy were significantly higher for patients with CHB than for control patients. Except for emergency room costs, postdiagnosis costs per month of the patients with CHB were significantly higher than those of the corresponding control patients. Examination of an HMO database showed that, compared with patients without CHB, patients with CHB had significantly higher health care costs around and after the CHB diagnosis.

Lesbians discuss beauty and aging

ABSTRACT Two conversations with three aging lesbians are presented to identify and explore different definitions of beauty and how these definitions change and are influenced by age. The three women interviewed believe beauty is more than skin deep, yet they differ regarding specific components of beauty. Two believe that their definition of beauty has changed as they age and one believes that her definition has remained basically unchanged through the years. Topics of discussion include: beauty role models, the impact of the American beauty standard on their self-esteem, and what they look for in potential partners. Through these women's diverse opinions on how beauty is defined and experienced by older lesbians, we see that there is no one perspective representing all older women.

Reflective meniscometry: a non-invasive method to measure tear meniscus curvature

AIMS

To devise a method to measure tear meniscus curvature by a non-invasive specular technique.

METHODS

A photographic system was devised. The system consisted of a camera and an illuminated target with a series of black and white stripes oriented parallel to the axis of the lower tear meniscus. The target was mounted on a flash gun close to the objective of a Brown macrocamera and calibrated using a graduated series of glass capillaries of known diameter, ground down to expose the inner wall. It was then applied to normal human eyes (n = 45) to measure the tear meniscus curvature. A video system was also assessed which provided qualitative online information about the tear meniscus.

RESULTS

Using the photographic system, measured values for capillary radii were in excellent agreement with theoretical calculations (r2 = 0.996, p < 0.0001). The radii of curvature of lower tear menisci in normal human subjects (mean 0.365 (SD 0.153) mm, range 0.128-0.736; n = 45) were similar to those reported in the literature. Both systems demonstrated variations in meniscus shape. The video system provided stable images of human menisci over prolonged periods of time and promises to be useful for the analysis of dynamic changes in meniscus volume.

CONCLUSIONS

Reflective meniscometry is a non-invasive technique providing quantitative information about tear meniscus shape and volume and of potential value in the study of ocular surface disease.

Image acquisition context: procedure description attributes for clinically relevant indexing and selective retrieval of biomedical images

OBJECTIVE

To support clinically relevant indexing of biomedical images and image-related information based on the attributes of image acquisition procedures and the judgments (observations) expressed by observers in the process of image interpretation.

DESIGN

The authors introduce the notion of "image acquisition context," the set of attributes that describe image acquisition procedures, and present a standards-based strategy for utilizing the attributes of image acquisition context as indexing and retrieval keys for digital image libraries.

METHODS

The authors' indexing strategy is based on an interdependent message/terminology architecture that combines the Digital Imaging and Communication in Medicine (DICOM) standard, the SNOMED (Systematized Nomenclature of Human and Veterinary Medicine) vocabulary, and the SNOMED DICOM microglossary. The SNOMED DICOM microglossary provides context-dependent mapping of terminology to DICOM data elements.

RESULTS

The capability of embedding standard coded descriptors in DICOM image headers and image-interpretation reports improves the potential for selective retrieval of image-related information. This favorably affects information management in digital libraries.

Comparison of 5-fluorouracil pharmacokinetics in patients receiving continuous 5-fluorouracil infusion and oral uracil plus N1-(2'-tetrahydrofuryl)-5-fluorouracil

Plasma 5-fluorouracil (5-FU) levels were compared in the same patients after approximately equimolar doses (1.9 mmol/ m2/day) of 5-day continuous i.v. infusion of 5-FU (CIFU) and oral administration of a formulation of two combined pharmacological agents, uracil (U) plus N1-(2'-tetrahydrofuryl)-5-fluorouracil (ftorafur or FT), a prodrug of 5-FU. Ten patients received CIFU for 5 days, then, after a week wash-out period, began the 28-day oral UFT regimen, which was given in three daily divided doses. Following 1 h of CIFU, the plasma 5-FU levels reached a steady state of 0.6+/-0.2 microM (mean+/-SD; day 1), which was maintained for the entire 5-day infusion period (0.6+/-0.1 microM). In contrast, the maximum 5-FU concentrations (Cpmax) generated from oral UFT at 1 h after dose administration on days 1 and 5 were 2.1+/-1.5 microM and 2.3+/-1.9 microM, respectively, which were higher than the steady-state levels during CIFU. These high 5-FU levels disappeared with an apparent elimination half-life (tl/2,beta) of 5.2+/-2.4 h (day 1) and 7.2+/-3.9 h (day 5). On day 1 of both regimens, CIFU patients had significantly larger 5-FU area under the concentration versus time curve (AUC0-8h) values (4.4+/-1.3 microM.h) than the AUC value when they received the UFT regimen (2.6+/-1.7 microM.h; P = 0.02). However, by day 5, there were no significant differences between AUC0-8 h values in patients receiving CIFU and UFT, respectively (4.8+/-1.5 microM.h versus 3.8+/-2.2 microM.h; P = 0.30)]. On day 5, the average concentration of the metabolite 5-FU at steady-state (Css,aver) within dose interval of 8 h (0.48+/-0.28 microM) for the oral UFT treatment is comparable with the Cpss values of 5-FU from CIFU-treated patients. The post-UFT generated 5-FU pharmacokinetic parameters (higher Cp(mx, comparable Css,aver, equal AUC values, and longer apparent t1/2,beta of 5-FU) may make oral UFT a preferred method of delivering this fluoropyrimidine over CIFU. In addition, oral UFT would eliminate the incidence of venous thrombosis and catheter-related infections sometimes seen in patients treated with CIFU. Furthermore, the convenience and decreased cost of oral administration may be preferable for many patients, particularly those receiving 5-FU for palliation.

Regulation of local tissue-type plasminogen activator release by endothelium-dependent and endothelium-independent agonists in human vasculature

OBJECTIVES

This study sought to define the local regulation of vascular tissue-type plasminogen activator (t-PA) release.

BACKGROUND

The vascular endothelium, through the production of t-PA and plasminogen activator inhibitor (PAI-1), is an important regulator of fibrinolysis. Plasma t-PA levels increase in response to adrenergic stimulation; however, it is unclear whether this increase is the result of systemic reflex responses or direct effects on the vascular endothelium.

METHODS

Forearm blood flow dose responses were generated to low doses of agonist infused directly into the brachial artery in 15 normotensive men (mean [+/-SE] age 28.9 +/- 2.2 years). Simultaneous arterial and venous blood samples were drawn at baseline and in response to the intraarterial administration of isoproterenol (400 ng/min), methacholine (8 microg/min) and sodium nitroprusside (SNP) (8 microg/min). PAI-1 and t-PA antigen levels were measured by enzyme-linked immunosorbent assay, and the net release across the forearm was calculated.

RESULTS

Forearm plasma flow increased significantly from baseline (1.4 +/- 0.2 ml/100 ml per min) after administration of isoproterenol, methacholine and SNP (9.7 +/- 1.9, 8.7 +/- 1.9 and 6.7 +/- 1.1 ml/100 ml per min, respectively) (p < 0.001 by analysis of variance). Baseline net t-PA release (0.7 +/- 0.3 ng/100 ml per min) increased significantly after administration of isoproterenol (26.2 +/- 11.6 ng/100 ml per min, p = 0.005) and methacholine (15.3 +/- 5.5 ng/100 ml per min, p = 0.001) but not after administration of SNP (1.8 +/- 2.2 ng/100 ml per min, p = 0.84). There was no net release of PAI-1 across the vascular bed.

CONCLUSIONS

Marked, rapid local t-PA release occurred in response to isoproterenol, a beta-adrenoceptor agonist, and methacholine, an endothelium-dependent nitric oxide agonist, in the human forearm. This effect was selective and independent of the effects of shear stress due to increased flow because SNP induced similar increases in forearm blood flow without affecting t-PA release. Vascular t-PA release may be a potentially valuable tool for evaluating endothelial function in diseases associated with increased risk of thrombosis.

Identification and characterization of mutations in hepatitis B virus resistant to lamivudine. Lamivudine Clinical Investigation Group

Cirrhosis and hepatocellular carcinoma occur as long-term complications of chronic hepatitis B virus (HBV) infection. Antiviral therapy is potentially a successful approach for the treatment of patients with HBV infection, which includes the nucleoside analog, lamivudine [(-)2'-deoxy-3'-thiacytidine, 3TC]. Although resistance to lamivudine therapy has been reported in several HBV-infected patients, the pattern of resistance-associated mutations in HBV has not been fully characterized. We report a DNA sequence database that includes a 500-base pair region of the HBV polymerase gene from 20 patients with clinical manifestations of lamivudine resistance. Analysis of the database reveals two patterns of amino acid substitutions in the tyrosine, methionine, aspartate, aspartate (YMDD) nucleotide-binding locus of the HBV polymerase. HBV DNA from the sera of patients in Group I exhibits a substitution of valine for methionine at residue 552, accompanied by a substitution of methionine for leucine at residue 528. Patients in Group II had only an isoleucine-for-methionine substitution at position 552. Reconstruction of these mutations in an HBV replication-competent plasmid was performed in a transient transfection cell assay to determine the function/relevance of these mutations to lamivudine resistance. Both Group I and Group II mutations resulted in a substantial decrease in sensitivity to lamivudine treatment (> 10,000-fold shift in IC50 over wild-type [wt] IC50), strongly indicating that these mutations were involved in resistance to lamivudine. A hypothetical model of the HBV reverse transcriptase has been generated for further study of the role of these mutations in lamivudine resistance.

Neuroendocrine, appetitive and behavioural responses to d-fenfluramine in women recovered from anorexia nervosa

BACKGROUND

Increased central serotonin (5-HT) function has been hypothesised to be a vulnerability trait in anorexia nervosa.

METHODS

Eighteen women with a history of DSM-III-R anorexia nervosa and 18 female controls were examined. The subjects had recovered weight and menstrual function. A placebo-controlled d-fenfluramine test was used. Subjects ingested d-fenfluramine or placebo and after three hours were offered a 'free' meal. The amounts eaten were recorded and plasma cortisol and prolactin levels were measured. Questionnaires related to eating attitudes and behaviour, to personality, and to mood were administered.

RESULTS

Unlike the control subjects, those recovered from anorexia nervosa did not show the expected appetite-suppressing responses to d-fenfluramine; their eating attitudes and behaviour were more restrained, 'negative' perfectionism was more pronounced, and post-meal plasma cortisol levels did not rise as expected.

CONCLUSIONS

Our results do not suggest that increased central 5-HT function is a trait marker in anorexia nervosa, but dysregulation in part of the central 5-HT system may be a vulnerability factor. The flattened post-meal response to cortisol in the subjects who had recovered from anorexia nervosa suggests that their hypothalamic pituitary--adrenal axis may be altered and deserves further investigation.

Expression of neu differentiation factor during the periimplantation period in the mouse uterus

Complex cellular interactions occur between the blastocyst and the uterus during implantation. The expression of various polypeptide growth factors and their receptors in the uterus and/or blastocyst during the periimplantation period suggest that growth factors participate in the implantation process. Neu differentiation factor (NDF) is a member of the epidermal growth factor (EGF) family of growth factors and is represented by multiple conserved isoforms. The expression of several EGF-like ligands in the periimplantation uterus has been characterized, including EGF, heparin binding-EGF, transforming growth factor alpha, amphiregulin, betacellulin, and epiregulin. We analyzed the expression pattern of NDF in the periimplantation mouse uterus because of its mitogenic and differentiation-promoting effects. By using Northern analysis and isoform-specific polymerase chain reaction, we found that multiple isoforms are expressed in the periimplantation uterus. NDF displays a highly restricted temporal and spatial expression, with autoradiographic signals localized to the uterine stroma immediately surrounding the implanting blastocyst. NDF expression was absent in mice with delayed implantation but briefly reappeared with the same restricted distribution after termination of the delay by an injection of estrogen. Taken together, these results suggest that an activated blastocyst is required for the expression of NDF and that multiple isoforms may be involved in the complex network of cell-signaling events between the implanting blastocyst and the receptive uterus.

The ideal role of the nurse teacher in the clinical area: a comparison of the perspectives of mental health, learning difficulties and general nurses

This paper reports findings from a study that explored trained nurses' and student nurses' perceptions of the nurse teachers' ideal role in the clinical area. Findings demonstrate a dichotomy of opinion regarding the ideal role of the nurse teacher in the clinical area that relates to the nursing specialties in which trained nurses work. Trained nurses working in general nursing areas favoured a product-focused, inspectorate supervisory role for nurse teachers. Conversely, trained nurses working in mental health and learning difficulties areas favoured a supportive, supervisory role for the nurse teacher that emphasized the learning process and encouraged reflection. The consequence of the different models used for student nurses' experience of supervision are discussed and the issue of nurse teachers' clinical credibility is explored. It is suggested that trained nurses, nurse teachers and student nurses should be involved in negotiating and constructing the role that nurse teachers play in the clinical area.

An evaluation of linear model analysis techniques for processing images of microcirculation activity

Sequences of images of the cortical surface can be processed to reveal information about the cortical microcirculation, regional cerebral blood flow (rCBF), and changes induced by neuronal activity. This study examined the use of different analysis methodologies on intrinsic optical images taken from rat sensory motor cortex and testes. Generalized linear model (GLM) analysis was used and compared with standard signal processing methods including principal component analysis. The GLM method has been used by Friston et al. (1994, Hum. Brain Map., 1: 214-220) in the analysis of functional magnetic resonance imagery to identify regions of focal activity. We investigated the use of this method to analyze video image data of the modulation of rCBF from rat cortex. The results revealed spatiotemporal variations in rCBF in response to stimulation within local regions of cortex. The advantage of the GLM method is that it augments ordinary signal processing methods with an estimate of statistical reliability. The use of different wavelengths of illumination reveals spatial structures with different temporal relationships. In image time series data collected under green and red illumination a phase difference was found in the low frequency approximately 0.1 Hz vasomotion oscillation. This phase difference occurred in data from both cortex and testes. A possible explanation of these differences is that the spectral absorption characteristics of the tissue reflect changes in the volume proportions of the different hemoglobin derivatives in interacting with the modulation of the volume of blood. It is suggested that the combination of these effects produces the phase differences we detect.

The use of heparin and normal saline flushes in neonatal intravenous catheters

PURPOSE

To compare the effects of heparin versus normal saline flush solutions on the duration of patency of peripheral IV catheters in neonates.

METHODS

A quasi experimental design compared the outcomes in 87 infants who were 32 weeks or greater gestation at birth. Thirty-three received heparin and 54 received normal saline.

RESULTS

There were 159 starts among the subjects. No statistically significant difference in duration of patency between the groups was found. The duration was significantly longer for term than preterm infants and for insertion in scalp, arm, or hand than for leg or foot.

CONCLUSIONS

Gestational age and site of insertion were the only predictor variables related to duration of patency for IV catheters.

Stimulation of the sympathetic perimesenteric arterial nerves releases neuropeptide Y potentiating the vasomotor activity of noradrenaline: involvement of neuropeptide Y-Y1 receptors

Neuropeptide Y (NPY) appears to be involved in the sympathetic regulation of vascular tone. To assess the putative role of NPY in mesenteric circulation, the release and biological effect of NPY were examined after electrical stimulation of perimesenteric arterial nerves. Nerve stimulation with trains of 2-30 Hz increased the perfusion pressure of the arterially perfused rat mesenteric bed in a frequency- and time-dependent fashion. Trains of 15-30 Hz significantly displaced to the left, approximately threefold, the noradrenaline (NA)-induced pressor concentration-response curve, in addition to increasing significantly its efficacy. Perfusion with 10 nM exogenous NPY mimicked the electrical stimulation effect, causing a threefold leftward shift of the NA concentration-response curve and increasing the maximal NA response. These effects were antagonized by 100 nM BIBP 3226, indicating the activity of NPY-Y1 receptors. Electrical stimulation of the perimesenteric nerves released immunoreactive NPY (ir-NPY) in a frequency-dependent fashion; the ir-NPY coelutes with synthetic NPY as confirmed by HPLC. Both the electrically induced pressor response and the calcium-dependent release of NPY were obliterated in preparations perfused with 1 microM guanethidine or in rats pretreated intravenously for 48 h with 6-hydroxydopamine, thus revealing the sympathetic origin of these phenomena. Only a small proportion of the total NPY content in the perimesenteric arterial nerves is released after electrical stimulation. Chromatographic studies of the physiological sources of the ir-NPY support that NPY fragments are generated via peptidase degradation. The present findings demonstrate that NPY is released from the perimesenteric arterial sympathetic nerves and acts, via the activation of NPY-Y1 receptors, as the mediator responsible for the potentiation of NA's effect on perfusion pressure in the isolated rat mesenteric bed.

Inpatient deaths from acute myocardial infarction, 1982-92: analysis of data in the Nottingham heart attack register

OBJECTIVE

To assess longitudinal trends in admissions, management, and inpatient mortality from acute myocardial infarction over 10 years.

DESIGN

Retrospective analysis based on the Nottingham heart attack register.

SETTING

Two district general hospitals serving a defined urban and rural population.

SUBJECTS

All patients admitted with a confirmed acute myocardial infarction during 1982-4 and 1989-92 (excluding 1991, when data were not collected).

MAIN OUTCOME MEASURES

Numbers of patients, background characteristics, time from onset of symptoms to admission, ward of admission, treatment, and inpatient mortality.

RESULTS

Admissions with acute myocardial infarction increased from 719 cases in 1982 to 960 in 1992. The mean age increased from 62.1 years to 66.6 years (P < 0.001), the duration of stay fell from 8.7 days to 7.2 days (P < 0.001), and the proportion of patients aged 75 years and over admitted to a coronary care unit increased significantly from 29.1% to 61.2%. A higher proportion of patients were admitted to hospital within 6 hours of onset of their symptoms in 1989-92 than in 1982-4, but 15% were still admitted after the time window for thrombolysis. Use of beta blockers increased threefold between 1982 and 1992, aspirin was used in over 70% of patients after 1989, and thrombolytic use increased 1.3-fold between 1989 and 1992. Age and sex adjusted odds ratios for inpatient mortality remained unchanged over the study period.

CONCLUSIONS

Despite an increasing uptake of the "proved" treatments, inpatient mortality from myocardial infarction did not change between 1982 and 1992.