Heart failure: highlights from new consensus guidelines

New guidelines for managing heart failure urge physicians to identify patients likely to benefit from therapy, obtain an echocardiogram to measure the ejection fraction, and, in patients with systolic dysfunction (i.e., an ejection fraction < or = 40%), institute therapy with an angiotensin-converting enzyme (ACE) inhibitor and a beta-blocker if at all possible. Digoxin and diuretics can relieve symptoms but do not affect the mortality rate. Spironolactone in low nondiuretic doses may reduce mortality when added to baseline drug regimens. The proper role of angiotensin II receptor blocking agents has yet to be determined.

Is dipalmitoylphosphatidylcholine a substrate for convertase?

Convertase has homology with carboxylesterases, but its substrate(s) is not known. Accordingly, we determined whether dipalmitoylphosphatidylcholine (DPPC), the major phospholipid in surfactant, was a substrate for convertase. We measured [(3)H]choline release during cycling of the heavy subtype containing [(3)H]choline-labeled DPPC with convertase, phospholipases A(2), B, C, and D, liver esterase, and elastase. Cycling with liver esterase or peanut or cabbage phospholipase D produced the characteristic profile of heavy and light peaks observed on cycling with convertase. In contrast, phospholipases A(2), B, and C and yeast phospholipase D produced a broad band of radioactivity across the gradient without distinct peaks. [(3)H]choline was released when natural surfactant containing [(3)H]choline-labeled DPPC was cycled with yeast phospholipase D but not with convertase or peanut and cabbage phospholipases D. Similarly, yeast phospholipase D hydrolyzed [(3)H]choline from [(3)H]choline-labeled DPPC after incubation in vitro, whereas convertase, liver esterase, or peanut and cabbage phospholipases D did not. Thus convertase, liver esterase, and plant phospholipases D did not hydrolyze choline from DPPC either on cycling or during incubation with enzyme in vitro. In conclusion, conversion of heavy to light subtype of surfactant by convertase may require a phospholipase D type hydrolysis of phospholipids, but the substrate in this reaction is not DPPC.

Medical day hospital care for the elderly versus alternative forms of care

BACKGROUND

Geriatric day hospitals provide multi-disciplinary rehabilitation in an outpatient setting. Concern has been expressed that evidence for effectiveness is equivocal and that day hospital care is expensive.

OBJECTIVES

To assess the effects of medical day hospitals for elderly people.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, Sigle, Bids, and Cinahl up to January 1997, and reference lists of articles. We also searched Index Medicus and International Dissertation Abstracts up to January 1997. We contacted authors of previous studies of day hospital care.

SELECTION CRITERIA

Randomised trials comparing geriatric medical day hospitals with alternative forms of care. The participants were elderly medical patients. The outcomes were death, place of residence, dependency, global 'poor' outcome (death, institutionalisation or dependency), activities of daily (ADL) score, subjective health status, patient satisfaction, and resource use.

DATA COLLECTION AND ANALYSIS

Three reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Twelve studies were included involving 22 day hospitals and 2867 patients. Five studies compared day hospital with comprehensive elderly care, four compared day hospital with domiciliary care and three compared day hospital with no comprehensive elderly care. There were no significant differences between day hospital attendance and comparison treatments for the outcomes of death, death or requiring institutional care, death or deterioration in ADL. When death or a 'poor' outcome at follow up was examined there was a significant difference in favour of day hospital attendance when compared to no comprehensive elderly care (odds ratio 0.73; 95% confidence interval 0.53-1.00; P < 0.05). Dependency was measured in 11 studies using a variety of ADL measures; two described short-term improvement for the day hospital group, one reported improved outcome for the comparison group, while in the remainder there was no statistically significant difference. Using the outcome of deterioration in ADL among survivors, day hospital patients showed reduced odds of deterioration compared with those receiving no comprehensive elderly care (0.60; 0.38-0.97; P <0.05). When resource use was examined the day hospital group showed trends towards reductions in hospital bed use and placement of survivors in institutional care. Nine studies comparing treatment costs indicated that day hospital attendance was a more expensive option, although only two analyses took into account long-term care costs.

REVIEWER'S CONCLUSIONS

Medical day hospital care for the elderly appears to be more effective than no intervention but may have no clear advantage over other forms of comprehensive elderly medical services.

The treatment of neurogenic orthostatic hypotension with 3,4-DL-threo-dihydroxyphenylserine: a randomized, placebo-controlled, crossover trial

OBJECTIVE

To study the therapeutic effect and mechanism of action of 3,4-DL-threodihydroxyphenylserine (DL-DOPS) in neurogenic orthostatic hypotension.

METHODS

The blood pressure (BP) response to an orthostatic challenge on DL-DOPS was compared with that of placebo in a randomized, double-blind, placebo-controlled, crossover trial in 10 patients. The mechanism of action of DOPS was studied by measuring forearm vascular resistance and changes in supine and upright plasma DL-DOPS and norepinephrine levels. The effect of DL-DOPS on the quality of life was determined by questionnaire.

RESULTS

DL-DOPS increased the supine (p<0.001) and upright (p<0.05) systolic blood pressure (SBP) and diastolic blood pressure (DBP) (both p<0.01). The peak SBP on DL-DOPS in the supine position occurred 300 minutes after ingestion of the medication. The increase in BP was accompanied by an increase in plasma levels of norepinephrine and DL-DOPS in both the supine and upright positions after DL-DOPS ingestion (p<0.0001). There was a trend toward improvement in symptoms of orthostatic intolerance.

CONCLUSION

DL-DOPS improved features of neurogenic orthostatic hypotension in patients with central and peripheral autonomic nervous system disease. There was an increase in plasma norepinephrine. No major side effects occurred.

Babies sleeping with parents: case-control study of factors influencing the risk of the sudden infant death syndrome. CESDI SUDI research group

OBJECTIVE

To investigate the risks of the sudden infant death syndrome and factors that may contribute to unsafe sleeping environments.

DESIGN

Three year, population based case-control study. Parental interviews were conducted for each sudden infant death and for four controls matched for age, locality, and time of sleep.

SETTING

Five regions in England with a total population of over 17 million people.

SUBJECTS

325 babies who died and 1300 control infants.

RESULTS

In the multivariate analysis infants who shared their parents' bed and were then put back in their own cot had no increased risk (odds ratio 0.67; 95% confidence interval 0.22 to 2.00). There was an increased risk for infants who shared the bed for the whole sleep or were taken to and found in the parental bed (9.78; 4.02 to 23.83), infants who slept in a separate room from their parents (10.49; 4.26 to 25.81), and infants who shared a sofa (48.99; 5.04 to 475.60). The risk associated with being found in the parental bed was not significant for older infants (>14 weeks) or for infants of parents who did not smoke and became non-significant after adjustment for recent maternal alcohol consumption (>2 units), use of duvets (>4 togs), parental tiredness (infant slept </=4 hours for longest sleep in previous 24 hours), and overcrowded housing conditions (>2 people per room of the house).

CONCLUSIONS

There are certain circumstances when bed sharing should be avoided, particularly for infants under four months old. Parents sleeping on a sofa with infants should always be avoided. There is no evidence that bed sharing is hazardous for infants of parents who do not smoke.

Night-time non-nutritive sucking in infants aged 1 to 5 months: relationship with infant state, breastfeeding, and bed-sharing versus room-sharing

AIM

Epidemiological studies suggest that pacifier use may be protective against SIDS but little is known of the relationship between pacifier use and other forms of non-nutritive sucking (NNS) in infancy, or of patterns of NNS during the night, when most SIDS deaths occur. We report the first longitudinal study of NNS by direct overnight observations in healthy infants in a sleep laboratory.

METHODS

Healthy, breast fed term infants (n = 10) were enrolled at birth, and sequential overnight polygraphic and infrared video recordings of infants with their mothers performed at monthly intervals from 1 to 5 months. Each month, mother baby pairs were randomized to 1 night bed-sharing (BN) then 1 room-sharing (RN), or vice versa. 'Episodes' of pacifier, own digit and mother's digit sucking (> 1 min) were identified and compared with state-matched control periods without sucking or feeding before and after each such episode.

RESULTS

329 episodes of NNS were identified in 749 h of video recording. The prevalence of pacifier sucking decreased with age, whilst digit sucking increased. Routine pacifier users rarely sucked their digits. There were temporal differences throughout the night in the distribution of different types of sucking and in infant state during and around sucking episodes. Sleeping in the 'non-routine' location was associated with a larger percentage of nights with sucking episodes and increased sleep latency. Bed sharing (routinely or on a given night) was associated with less sucking behavior and more breastfeeding. Non-nutritive sucking was not, however, associated with decreased total time breastfeeding per night or number of feeds per night.

CONCLUSION

Patterns of NNS during the night change with age and are affected by maternal proximity. Digit sucking has state modulating effects, and may be suppressed by pacifier use. Thus any benefits of pacifier use must be set against the potential loss of a self-directed ability to modulate state during the night, and possible shortening of breastfeeding duration.

No evidence of increased risk of colorectal cancer in individuals heterozygous for the Cys282Tyr haemochromatosis mutation

BACKGROUND AND AIMS

Previous studies have suggested that increased body iron stores and heterozygosity for haemochromatosis are associated with an increased risk of colorectal carcinoma. The aim of this study is to determine if there is an association between (i) colorectal carcinoma and heterozygosity for the Cys282Tyr mutation of the haemochromatosis gene (HFE) and (ii) this mutation and tumour site or stage.

METHODS

Two hundred and twenty-nine unselected patients (127 males, 102 females, mean age 68.0 years) with sporadic colorectal carcinoma and 228 controls (145 males, 83 females, mean age 69.7 years) were studied. DNA was tested for the presence of the Cys282Tyr mutation by digestion with Rsa1 and fragments separated by electrophoresis.

RESULTS

Twenty-one patients with colorectal cancer and 23 control subjects were heterozygous for the Cys282Tyr mutation of HFE (relative risk 0.90). There was no association between heterozygosity of the Cys282Tyr mutation and tumour site or stage.

CONCLUSIONS

Heterozygosity for the Cys282Tyr mutation of HFE does not appear to be a risk factor for colorectal carcinoma.

Endoscopic skull base surgery II: a new animal model for surgery of the posterior fossa

The field of skull base surgery has been influenced by a general philosophy that currently exists in modern surgical practice favoring less invasive means of managing surgical disease. Adapting techniques developed by general surgeons and other surgical subspecialists, skull base surgeons are now experimenting with endoscopy to resect tumors, manage vascular lesions, and manipulate critical intracranial structures. Lesions formerly requiring significant soft tissue dissection and craniotomy for exposure are now potentially amenable to treatment via a keyhole approach. As in other surgical specialties, however, a reliable animal model is necessary for experimentation with and development of new endoscopic techniques in the skull base. The swine provides just such a model, primarily due to craniofacial and skull base relationships that are analogous to humans. We have focused on the posterior skull base of the swine in this experiment: Via a retrosigmoid craniotomy we opened the dura of the posterior fossa and used endoscopes to visualize and manipulate the critical structures in this area. The cerebellum and midbrain were appreciated, as were cranial nerves V, VII, VIII, IX, X, and XI. Blood vessels on the surface of the midbrain were also identified. This experience further supports the use of the swine as an appropriate animal model for endoscopic skull base surgery.

The development of a collaborative stroke training programme for nurses

The effectiveness of multidisciplinary stroke rehabilitation may be enhanced by nurses and therapists adopting a single consistent approach to the positioning and mobilizing of patients. As patients can spend as little as 4% of the waking day receiving 'therapy' there is considerable potential for a more dynamic nursing intervention, which may contribute to improving patient care. We aimed to investigate whether physiotherapists could step back from direct patient treatment in order to participate in a structured training programme for nurses involved with patients recovering from stroke on an established elderly care rehabilitation ward in a district general hospital. Qualitative methods were used within a participatory action research framework to describe the development process and content of the training programme. Nursing staff, physiotherapists and their respective managers were interviewed to identify perceived training needs. This informed the structure and content of the training course and allowed insight into interprofessional working.

Outcome of de novo hepatitis C virus infection in heart transplant recipients

The outcome of de novo hepatitis C virus (HCV) infection in heart transplant recipients of HCV-antibody positive organs is not known. The aim of the study was to determine the short-term outcome of de novo HCV infection in recipients of HCV-positive donor organs. HCV-antibody negative recipients of HCV-antibody positive hearts were identified from January 1, 1991 to February 28, 1998. Control patients matched for year of transplantation were also identified. Twenty-eight patients (22 males, mean age of 56 +/- 11 SD) received hearts from HCV-antibody-positive donors. The control group was similar to the patients in all clinical and demographic aspects. Twenty-three patients had detectable viremia by reverse-transcription polymerase chain reaction (RT-PCR). Of these 23 patients with de novo HCV infection, 7 (30%) developed HCV-related liver disease. Three patients (13%) had chronic hepatitis and 4 patients (17%) developed severe acute cholestatic hepatitis (ACH). Mycophenolate mofetil (MMF) use (P =.04) and high viral load at onset of acute liver disease (P =.02) were associated with ACH. Overall survival was similar between patients with de novo HCV infection and controls (P =.20). Development of ACH (P =.02) and MMF use (P =.0009) were associated with decreased survival in patients with de novo HCV infection. The present study showed that survival of patients with de novo HCV infection was similar to a matched control group. HCV-related severe ACH is associated with a poor short-term outcome in patients with de novo HCV infection. MMF use may be associated with a higher incidence of HCV-related severe ACH and a poor short-term outcome.

Specialist gynaecologists and survival outcome in ovarian cancer: a Scottish national study of 1866 patients

OBJECTIVE

To determine whether specialist gynaecological surgeons improved survival in women with ovarian cancer when compared with general gynaecologists.

DESIGN

Retrospective case note review.

POPULATION

All women diagnosed with ovarian cancer in Scotland in 1987, 1992, 1993 and 1994.

METHODS

Data on prognostic factors and surgical and post-operative management was extracted from case notes. Surgeons were classified as specialist gynaecologists, general gynaecologists or general surgeons by an independent committee with no knowledge of an individual's outcome. Cox's proportional hazards model was used to determine the relative risk of a patient dying, if managed by specialist and general gynaecologists, after adjustment for age, histology, tumour differentiation, presence of ascites and socio-economic status. Analysis was performed separately for each FIGO stage.

MAIN OUTCOME MEASURES

Relative hazard ratios for survival up to three years.

RESULTS

Survival benefit for specialists varied according to the stage of the disease. The greatest benefit was observed among women with Stage III disease (44% of women presented at this stage) where there was a 25% (relative hazard ratio = 0.75, P = 0.005) reduction in the rate of dying for women operated on by specialist gynaecologists, compared with women operated on by general gynaecologists. Differential use of platinum chemotherapy did not explain this survival advantage. Specialist gynaecologists more often debulked tumour to < 2 cm than general gynaecologists in Stage III cases (36.3% vs 28.7%, P = 0.07). In women with Stage III carcinoma with > 2 cm remaining, survival was significantly improved for women treated by specialist gynaecologists (relative hazard ratio = 0.71, P = 0.007). No significant differences were observed for patients with Stages I, II and IV disease, although there were fewer deaths in women with early stage disease.

CONCLUSIONS

Specialist gynaecologists improve survival for some women with ovarian cancer.

Angiogenic factor VEGF is decreased in human colorectal neoplasms showing DNA microsatellite instability

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are two important determinants of angiogenesis in human cancers. Expression of VEGF and bFGF was examined by immunohistochemistry in 120 colorectal cancers. Neoplasms were classified according to the presence or absence of microsatellite instability determined at six microsatellite loci and labelled as a high microsatellite instability (MSI-H), low microsatellite instability (MSI-L) or microsatellite stable (MSS). Only 4/30 MSI-H cancers expressed VEGF (13 per cent), compared with 24/64 MSS cancers (38 per cent; p< 0.01). Fewer MSI-H cancers showed bFGF expression (38 per cent) than MSS cancers (53 per cent; p< 0.09). MSI-L cancers showed the same pattern as MSS cancers. Western blotting and immunohistochemistry showed that the tumour suppressor gene p53 was mutated infrequently in MSI-H cancers (8 per cent; p< 0. 001). Microvessel density counts using CD31 and UEA-1 demonstrated no difference in the number of blood vessels in MSI-H and MSS cancers. Although these results are consistent with the known role of wild-type p53 in down-regulating VEGF, no association was found between a mutation in p53 and VEGF or bFGF levels in all colonic neoplasms. This is the first evidence that MSI-H cancers may follow a different pathway to angiogenesis. The low frequency of VEGF expression amongst MSI-H cancers may partially explain why these cancers are less aggressive, with a better overall prognosis.

The antigonadotropic activity of a 19-nor-progesterone derivative is exerted both at the hypothalamic and pituitary levels in women

We have previously shown in postmenopausal women that a 19-nor-progesterone derivative, nomegestrol acetate (NOMA) had a strong antigonadotropic activity and that this effect was not mediated via the androgen receptor. The aim of the present study was to further assess the action of this progestin on gonadotropin secretion in women. To demonstrate at which level of the hypothalamo-pituitary-ovarian axis the gonadotropin inhibition was exerted, 10 normally cycling (NC) women, 3 women with a gonadotropin-independent ovarian function [McCune-Albright (MCA) syndrome], and 5 women with functional hypothalamic amenorrhea (FHA) participated in the study. NC women were treated orally with 5 mg NOMA for 21 days, after one control cycle. Plasma estradiol (E2) and progesterone, LH, and FSH levels were measured during each cycle. A frequent sampling study (every 10 min for 4 h), followed by a classic GnRH test (100 microg, i.v.), was performed on day 11. Women with MCA were studied before, during NOMA, and after long-acting GnRH agonist administration. In women with FHA, pulsatile GnRH (20 microg s.c., every 90 min) was given for two cycles with or without NOMA (5 mg for 21 days). In all NC women, ovulation was suppressed by NOMA. Mean plasma LH levels, LH pulse frequency, and the LH response to exogenous GnRH were significantly decreased. In MCA, neither NOMA nor GnRH agonist modified multiple ovarian cysts on ultrasound or plasma E2, levels which remained elevated, ruling out a direct ovarian effect. In FHA, pulsatile GnRH administration recreated a normal ovulatory menstrual cycle. Addition of NOMA prevented the increase of plasma E2, decreased the amplitude of LH pulses, and prevented ovulation. In view of this unexpected action of NOMA at the pituitary level, seven samples of normal human female pituitaries were tested for the presence of progesterone receptor (PR) using a double labeling immunocytochemical technique. The presence of PR was detected in the seven human pituitary tissues. In addition, PR was found to be expressed only in gonadotroph cells. In conclusion, NOMA, a 19-nor-P derivative, has a potent antigonadotropic activity exerted at the hypothalamic level, inhibiting ovulation in NC women. In women with FHA, NOMA decreased the gonadotropin stimulation induced by pulsatile GnRH administration. According to the presence of PR in gonadotroph cells of normal human pituitaries, 19-nor-progesterone derivatives may also act on the gonadotropin secretion at the pituitary level.

Autoantibodies interacting with purified native thyrotropin receptor

Native thyrotropin receptor (TSHR) was purified by immunoaffinity chromatography from membrane extracts of stably transfected L cells. An ELISA test was devised to study anti-TSHR autoantibodies directly. Comparison of native TSHR with bacterially expressed, denatured TSHR showed that the latter was not recognized by the autoantibodies, suggesting that they bind to conformational epitopes only present on the native receptor. The use of deglycosylated TSHR and of purified receptor ectodomain (alpha-subunit) showed that the autoantibodies recognized only the protein backbone moiety of the receptor and that their epitopes were localized entirely in its ectodomain. Autoantibodies were detected in 45 of 48 subjects with untreated Graves' disease and in 26 of 47 healthy volunteers. The affinity for the receptor was similar in the two groups (Kd = 0.25-1 x 10-10 M) and the autoantibodies belonged to the IgG class in all cases. Although the concentration of autoantibodies was higher in Graves' disease patients (3.50 +/- 0.36 mg.L-1) than in control subjects (1.76 +/- 0.21) (mean +/- SEM), there was an overlap between the groups. Receptor-stimulating autoantibodies (TSAb) were studied by measuring cAMP synthesis in stably transfected HEK 293 cells. Their characteristics (recognition of alpha-subunit, of deglycosylated TSHR, nonrecognition of bacterially expressed denatured receptor) were similar to those of the antibodies detected by the ELISA test. TSAb were only found in individuals with Graves' disease. The ELISA test measures total anti-TSHR antibodies, whereas the test using adenylate cyclase stimulation measures antibodies that recognize specific epitopes involved in receptor activation. Our observations thus disprove the hypothesis according to which Graves' disease is related to the appearance of anti-TSHR antibodies not present in normal subjects. Actually, anti-TSHR antibodies exist in many euthyroid subjects, in some cases even at concentrations higher than those found in patients with Graves' disease. What distinguishes the latter from normal subjects is the existence of subpopulation(s) of antibodies directed against specific epitope(s) of the receptor involved in its activation.

Effects of a physiotherapist-led stroke training programme for nurses

AIM

to assess the effects of a physiotherapist-led stroke training programme for nurses working in a rehabilitation ward on clinical practice and patient outcome.

METHOD

before and after group comparison with outcome assessment by observational and quantitative methods. Non-participant observation before and after the 5-month training programme recorded patient position, transfers and contact with nursing staff. Quantitative assessments of disability, satisfaction and mood were made at baseline, discharge and 4 months after stroke onset. We also noted selected stroke complications, rehabilitation ward length of stay and discharge destination.

RESULTS

there was a significant improvement in the number of observed 'good' transfers of patients undertaken by nurses (chi2 = 9.13, df = 1, P = 0.003) but the training programme had no impact on the time the patients spent in 'poor' positions. There was no significant difference between the two groups for Barthel index scores at discharge and at 4 months. Neither was there any significant difference in the Hospital Anxiety and Depression scale, occurrence of secondary complications, length of stay or the Patient and Carer Satisfaction Questionnaires.

CONCLUSION

within the limitations of the research design adopted, some improvements in clinical practice were reported but there were no significant differences in patient outcome. The training programme required no additional resources and should be replicable in most district general hospitals.

ED use of flexion-extension cervical spine radiography in the evaluation of blunt trauma

Dynamic cervical spine radiography (CSR) is used to detect ligamentous instability. We investigated the ED use of dynamic CSR through a retrospective descriptive review using a convenience sample study design at a university emergency department. Adult blunt trauma patients with static (lateral, AP, odontoid) and dynamic (flex, extend) CSR participated. 451 patients (52% male with mean age of 33.6 years) met entry criteria. Injury mechanisms were 74% MVA, 12% fall, 8% direct trauma, and 6% other. Indications for dynamic CSR were 100% traumatic mechanism, 86% neck pain, 70% midline neck tenderness, and 18% abnormal static CSR. Static CSR were normal in 372, 5 of which had abnormal dynamic CSR (5 cervical contour line disruption [CCLD], 2 posterior element abnormality [PEA]); of these 5 patients, none required invasive stabilization. Static CSR were abnormal in 79 patients (38 CCLD, 30 lordotic curve reversal, 17 PEA, 4 soft tissue swelling) of which 16 had abnormal dynamic CSR (9 increased CCLD, 4 PEA, and 4 fracture); of these 16 patients, 4 required invasive stabilization. Final diagnoses were 428 cervical soft tissue injury, 11 subluxation, 8 fracture, 2 fracture-subluxation, and 2 spinal cord injury without radiographic abnormality. Spine consultation was made in 12%. Stabilization therapy was required: 21 soft collar, 4 surgical, 3 halo-device, and 5 other. No complications of dynamic CSR were noted. The blunt trauma patient with neck complaints and an abnormal static CSR was more likely to have an abnormal dynamic CSR demonstrating a cervical injury requiring stabilization compared to patients with normal static CSR.

Comparison of candesartan, enalapril, and their combination in congestive heart failure: randomized evaluation of strategies for left ventricular dysfunction (RESOLVD) pilot study. The RESOLVD Pilot Study Investigators

BACKGROUND

We investigated the effects of candesartan (an angiotensin II antagonist) alone, enalapril alone, and their combination on exercise tolerance, ventricular function, quality of life (QOL), neurohormone levels, and tolerability in congestive heart failure (CHF).

METHODS AND RESULTS

Seven hundred sixty-eight patients in New York Heart Association functional class (NYHA-FC) II to IV with ejection fraction (EF) <0.40 and a 6-minute walk distance (6MWD) <500 m received either candesartan (4, 8, or 16 mg), candesartan (4 or 8 mg) plus 20 mg of enalapril, or 20 mg of enalapril for 43 weeks. There were no differences among groups with regard to 6MWD, NYHA-FC, or QOL. EF increased (P=NS) more with candesartan-plus-enalapril therapy (0.025+/-0.004) than with candesartan alone (0.015+/-0.004) or enalapril alone(0.015+/-0.005). End-diastolic (EDV) and end-systolic (ESV) volumes increased less with combination therapy (EDV 8+/-4 mL; ESV 1+/-4 mL; P<0.01) than with candesartan alone (EDV 27+/-4 mL; ESV 18+/-3 mL) or enalapril alone (EDV 23+/-7 mL; ESV 14+/-6 mL). Blood pressure decreased with combination therapy (6+/-1/4+/-1 mm Hg) compared with candesartan or enalapril alone (P<0.05). Aldosterone decreased (P<0.05) with combination therapy (23.2+/-5.3 pg/mL) at 17 but not 43 weeks compared with candesartan (0.7+/-7.8 pg/mL) or enalapril (-0.8+/-11. 3 pg/mL). Brain natriuretic peptide decreased with combination therapy (5.8+/-2.7 pmol/L; P<0.01) compared with candesartan (4. 4+/-3.8 pmol/L) and enalapril alone (4.0+/-5.0 pmol/L).

CONCLUSIONS

Candesartan alone was as effective, safe, and tolerable as enalapril. The combination of candesartan and enalapril was more beneficial for preventing left ventricular remodeling than either candesartan or enalapril alone.

Endoscopic skull base surgery I: a new animal model for pituitary surgery

Endoscopy has emerged as a new means to perform minimally invasive surgery of the skull base. Specifically, endoscopic techniques and instruments can be used to safely and effectively approach and resect tumors of the pituitary gland in humans. No animal model currently exists to serve as a template upon which to refine and develop endoscopic surgical technique in this region of the anatomy. We operated on two purpose-bred Hampshire-Yorkshire-Duroc hybrid swine to demonstrate the application of endoscopy to pituitary surgery. Based upon similar anatomical relationships in humans and swine between the oropharynx, nasopharynx, and skull base, we used a transoral, transpalatal approach to access the vomer of the swine. Under endoscopic exposure, we resected the vomer, entered the sphenoid sinus, and then resected the sphenoid septum, sella turcica, and adenohypophysis. Clear visualization of the pituitary, hypophyseal stalk, cavernous sinuses, and carotid prominences was achieved and documented with digital photography. Benefits and limitations of the technique were noted. These results have pertinent implications both for the study of the surgical anatomy of the swine craniofacial skeleton, and for future development of endoscopic surgical manipulation of the skull base.

Lung volume reduction surgery (LVRS) for chronic obstructive pulmonary disease (COPD) with underlying severe emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) has recently re-emerged as a surgical option for the treatment of end stage chronic obstructive pulmonary disease (COPD) due to underlying severe emphysema. Advocates of LVRS claim that it represents a significant breakthrough in the management of this challenging group of patients while sceptics point to uncertainty about the effectiveness of the operation.

METHODS

A systematic review was conducted of the evidence on the effects of LVRS in patients with end stage COPD secondary to severe emphysema.

RESULTS

The most rigorous evidence on the effectiveness of LVRS came from case series. Seventy five potentially relevant studies were identified and 19 individual series met the methodological criteria for inclusion. The pattern of results was consistent across individual studies despite a significant degree of clinical heterogeneity. Significant short term benefits occurred across a range of outcomes which appeared to continue into the longer term. Physiological improvements were matched by functional and subjective improvements. Early mortality rates were low and late mortality rates compared favourably with those of the general COPD population. However, the entire research base for the intervention is subject to the limitations of study designs without parallel control groups.

CONCLUSIONS

LVRS appears to represent a promising option in the management of patients with severe end stage emphysema. However, until the results of ongoing clinical trials are available, the considerable uncertainty that exists around the effectiveness and cost effectiveness of the procedure will remain.

Screening SMAD1, SMAD2, SMAD3, and SMAD5 for germline mutations in juvenile polyposis syndrome

BACKGROUND AND AIMS

Juvenile polyps occur in several Mendelian disorders, whether in association with gastrointestinal cancer alone (juvenile polyposis syndrome, JPS) or as part of known syndromes (Cowden, Gorlin, and Bannayan-Zonana) in association with developmental abnormalities, dysmorphic features, or extraintestinal tumours. Recently, some JPS families were shown to harbour germline mutations in the SMAD4 (DPC4) gene, providing further evidence for the importance of the TGFbeta signalling pathway in colorectal cancer. There remains, however, considerable, unexplained genetic heterogeneity in JPS. Other members of the SMAD family are excellent candidates for JPS, especially SMAD2 (which, like SMAD4, is mutated somatically in colorectal cancers), SMAD3 (which causes colorectal cancer when "knocked out" in mice), SMAD5, and SMAD1.

METHODS

SMAD1, SMAD2, SMAD3, and SMAD5 were screened for germline mutations in 30 patients with JPS and without SMAD4 mutations.

RESULTS

No mutations were found in any of these genes. A G-A C89Y polymorphism with possible effects on protein function was found in SMAD3, but the frequencies of the G and A alleles did not differ between patients with JPS and controls.

CONCLUSIONS

It remains to be determined whether or not this polymorphism is involved in a minor predisposition to colorectal or other carcinomas. SMAD4 may be the only member of the SMAD family which causes JPS when mutant in the germline. The other genes underlying JPS remain to be identified.

Sequence-tagged connectors: a sequence approach to mapping and scanning the human genome

The sequence-tagged connector (STC) strategy proposes to generate sequence tags densely scattered (every 3.3 kilobases) across the human genome by arraying 450,000 bacterial artificial chromosomes (BACs) with randomly cleaved inserts, sequencing both ends of each, and preparing a restriction enzyme fingerprint of each. The STC resource, containing end sequences, fingerprints, and arrayed BACs, creates a map where the interrelationships of the individual BAC clones are resolved through their STCs as overlapping BAC clones are sequenced. Once a seed or initiation BAC clone is sequenced, the minimum overlapping 5' and 3' BAC clones can be identified computationally and sequenced. By reiterating this "sequence-then-map by computer analysis against the STC database" strategy, a minimum tiling path of clones can be sequenced at a rate that is primarily limited by the sequencing throughput of individual genome centers. As of February 1999, we had deposited, together with The Institute for Genomic Research (TIGR), into GenBank 314,000 STCs ( approximately 135 megabases), or 4.5% of human genomic DNA. This genome survey reveals numerous genes, genome-wide repeats, simple sequence repeats (potential genetic markers), and CpG islands (potential gene initiation sites). It also illustrates the power of the STC strategy for creating minimum tiling paths of BAC clones for large-scale genomic sequencing. Because the STC resource permits the easy integration of genetic, physical, gene, and sequence maps for chromosomes, it will be a powerful tool for the initial analysis of the human genome and other complex genomes.

Block of (Na+,K+)ATPase with ouabain induces spreading depression-like depolarization in hippocampal slices

We used ouabain (100 microM) to block Na+,K(+)ATPase of in vitro rat hippocampal slices. This treatment was sufficient to cause the sudden depolarization that is the hallmark of both spreading depression (SD) and of the SD-like anoxic depolarization (AD). This depolarization was accompanied by a large and sudden increase in [K](o), also reminiscent of that observed during both SD and AD. Ouabain-induced SD did not require a complete inactivation of Na+,K(+)ATPase, as it occurred when the enzyme was still capable of providing recovery of both V(o) and [K](o). The data indicate that functional inactivation of Na+,K(+)ATPase per se initiates events that lead to an SD-like AD. This ouabain-induced depolarization was not affected by block of synaptic transmission, instead it was abolished by hyperosmolarity of the extracellular space. The possible relevance of these findings to the pathophysiology of AD is discussed.