A novel suture anchor of high-density collagen compared with a metallic anchor. Results of a 12-week study in sheep

We report the early mechanical properties and histologic findings of a high-density, type I collagen bone anchor. This new anchor was compared with a traditional metallic anchor in a sheep patellar tendon model. No difference in strength of the repair was noted between the two devices at any time point. The insertions on the repaired side approached the strength of the nonoperated side by 12 weeks. Histologic analysis showed that the collagen anchor integrated with the surrounding bone by 6 weeks, and there was little degradation at 12 weeks. The high-density collagen anchor supported tendon healing to bone comparable with that seen with a traditional metallic device, but it has the potential advantage of the anchor being incorporated into bone.

Large-scale analysis of gene expression changes during acute and chronic exposure to [Delta]9-THC in rats

Large-scale cDNA microarrays were employed to assess transient changes in gene expression levels following acute and chronic exposure to cannabinoids in rats. A total of 24,456 cDNA clones were randomly selected from a rat brain cDNA library, amplified by PCR, and arrayed at high density to investigate differential gene expression profiles following acute (24 h), intermediate (7 days), and chronic (21 days) exposure to Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the psychoactive ingredient of marijuana. Hippocampal mRNA probes labeled with (33)P obtained from both vehicle and Delta(9)-THC-treated animals were hybridized with identical cDNA microarrays. Results revealed a total of 49 different genes altered by Delta(9)-THC exposure; of these, 28 were identified, 10 had homologies to expressed sequence tags (ESTs), and 11 had no homology to known sequences in the GenBank database. Chronic or acute cannabinoid receptor activation altered expression of several genes (i.e., prostaglandin D synthase, calmodulin) involved in biochemical cascades of cannabinoid synthesis or cannabinoid effector systems. Other genes [i.e., neural cell adhesion molecule (NCAM), myelin basic protein], whose relation to cannabinoid system function was not immediately obvious, were also significantly altered. Verification of the changes obtained with the large-scale screen was determined by RNA dot blots in different groups of animals treated the same as those in the large-scale screen. Results are discussed in terms of the different types of genes affected at different times during chronic Delta(9)-THC exposure.

Short- and intermediate-term clinical outcomes from direct myocardial laser revascularization guided by biosense left ventricular electromechanical mapping

BACKGROUND

Direct myocardial revascularization (DMR) has been examined as an alternative treatment for patients with chronic refractory myocardial ischemic syndromes who are not candidates for conventional coronary revascularization. Methods and Results-We used left ventricular electromagnetic guidance in 77 patients with chronic refractory angina (56 men, mean age 61+/-11 years, ejection fraction 0.48+/-0.11) to perform percutaneous DMR with an Ho:YAG laser at 2 J/pulse. Procedural success (laser channels placed in prespecified target zones) was achieved in 76 of 77 patients with an average of 26+/-10 channels (range 11 to 50 channels). The rate of major in-hospital cardiac adverse events was 2.6%, with no deaths or emergency operations, 1 patient with postprocedural pericardiocentesis, and 1 patient with minor embolic stroke. The rate of out-of-hospital adverse cardiac events (up to 6 months) was 2.6%, with 1 patient with myocardial infarction and 1 patient with stroke. Exercise duration after DMR increased from 387+/-179 to 454+/-166 seconds at 1 month and to 479+/-161 seconds at 6 months (P=0.0001). The time to onset of angina increased from 293+/-167 to 377+/-176 seconds at 1 month and to 414+/-169 seconds at 6 months (P=0.0001). Importantly, the time to ST-segment depression (>/=1 mm) also increased from 327+/-178 to 400+/-172 seconds at 1 month and to 436+/-175 seconds at 6 months (P=0.001). Angina (Canadian Cardiovascular Society classification) improved from 3.3+/-0.5 to 2.0+/-1.2 at 6 months (P<0.001). Nuclear perfusion imaging studies with a dual-isotope technique, however, showed no significant improvements at 1 or 6 months.

CONCLUSIONS

Percutaneous DMR guided by left ventricular mapping is feasible and safe and reveals improved angina and prolonged exercise duration for up to a 6-month follow-up.

Ability of laboratories to detect emerging antimicrobial resistance in nosocomial pathogens: a survey of project ICARE laboratories

A proficiency testing project was conducted among 48 microbiology laboratories participating in Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology). All laboratories correctly identified the Staphylococcus aureus challenge strain as oxacillin- resistant and an Enterococcus faecium strain as vancomycin-resistant. Thirty-one (97%) of 32 laboratories correctly reported the Streptococcus pneumoniae strain as erythromycin-resistant. All laboratories testing the Pseudomonas aeruginosa strain against ciprofloxacin or ofloxacin correctly reported the organism as resistant. Of 40 laboratories, 30 (75%) correctly reported resistant MICs or zone sizes for the imipenem- and meropenem-resistant Serratia marcescens. For the extended-spectrum beta-lactamase (ESBL)-producing strain of Klebsiella pneumoniae, 18 (42%) of 43 laboratories testing ceftazidime correctly reported ceftazidime MICs in the resistant range. These results suggest that current testing generally produces accurate results, although some laboratories have difficulty detecting resistance to carbapenems and extended-spectrum cephalosporins. This highlights the need for monitoring how well susceptibility test systems in clinical laboratories detect emerging resistance.

Sensory evoked potentials in SIV-infected monkeys with rapidly and slowly progressing disease

Human immunodeficiency virus (HIV-1) infects the central nervous system (CNS) early in the course of disease progression and leads to some form of neurological disease in 40-60% of cases. Both symptomatic and asymptomatic HIV-infected subjects also show abnormalities in evoked potentials. As part of an effort to further validate an animal model of the neurological disease associated with lentiviral infection, we recorded multimodal sensory evoked potentials (EPs) from nine rhesus macaques infected with passaged strains of SIVmac (R71/E17), prior to and at 1 month intervals following inoculation. The latencies of forelimb and hindlimb somatosensory evoked potentials (SEP) and flash visual evoked potentials (VEP) were measured. Within 14 weeks of inoculation, all but two animals had progressed to end-stage disease (rapid progressors). The two animals with slowly progressing disease (AQ15 and AQ94) had postinoculation life spans of 109 and 87 weeks, respectively. No significant changes were observed in evoked potentials recorded during the control period or at any time in the animals with slowly progressing disease. However, all of the monkeys with rapidly progressing disease exhibited increases in latency for at least one evoked potential type. The overall mean increases in somatosensory and visual evoked potential peak latencies for the rapid progressors were 22.4 and 25.3%, respectively. For comparison, the changes in slow progressors were not significant (1.8 and -1.9%, respectively). These results, coupled with our previous finding of slowed motor evoked potentials in the same cohort of macaques (Raymond et al.: J Neurovirol 1999;5:217-231), demonstrate a broad and somewhat variable pattern of viral injury to both sensory and motor system structures, resembling the findings in HIV-infected humans. These results coupled with our earlier work demonstrating cognitive and motor behavioral impairments in the same monkeys support the use of the SIVmac-infected rhesus macaque as a model of AIDS-related neurological disease.

Abstinent-contingent housing and treatment retention among crack-cocaine-dependent homeless persons

This study investigated Behavioral Day Treatment attendance in relation to treatment outcome among homeless persons dependent on crack-cocaine. Participants (N = 141) were 72.3% male and 82.7% African American. Days attended, activities attended, and follow-up rates over a 12-month period were positively affected by the more attractive treatment of providing immediate, rent-free, abstinent-contingent housing during a 2-month Behavioral Day Treatment program. Results replicated previous findings that abstinence is a function of treatment attendance and more treatment is associated with greater abstinence. The loss of predictive power at long-term follow-up, limitations of a retrospective design, need to identify most predictive therapeutic activity types, and potential influence of mental disorders were discussed. Analytical techniques used in this study allows for the planning, predictability, and measurement of drug abuse treatment success as a function of service utilization.

Initiating abstinence in cocaine abusing dually diagnosed homeless persons

This study measured effectiveness of behavioral day treatment plus abstinence contingent housing and work therapy (DT+) versus behavioral day treatment alone (DT). A randomized controlled trial assessed participants at baseline, 2 and 6 months. Participants (N=110) met criteria for cocaine abuse or dependence, non-psychotic mental disorders, and homelessness. DT+ achieved greater abstinence at 2 and 6 months and more days housed at 6 months than DT. Effectiveness of DT+ was demonstrated, with greatest impacts on abstinence outcomes. Results replicated earlier work demonstrating effectiveness of behavioral day treatment and contingency management as an effective combination for cocaine abusing homeless persons.

Chronic fatigue syndrome: a woman's dilemma

Chronic Fatigue Syndrome (CFS) is an illness characterized by fatigue with varying levels of disability. According to the Centers for Disease Control (CDC) there are 2 to 5 million people in the United States who suffer from CFS and a disproportionate number are women. There are many theories of etiology of the condition and controversy has surrounded recommendations for diagnosis and treatment. CFS can mimic other diseases and women are doubly affected since many have comorbid conditions. While diagnoses and treatment are critical to the health of women, having the disease and coping with the symptoms may have a greater impact on their well-being and quality of life. The authors report qualitative data describing the experience of having CFS (N = 22) and quantitative responses of 42 CFS sufferers reporting psychosocial factors. The psychosocial factors were measured by the Derogatis Stress Profile (DSP), Spielberger Trait-Anger Scale, Ways of Coping Survey, Profile of Moods States (POMS) Survey, and the Perceived Stress Scale. The findings indicate that CFS changes the lives of women who suffer with the disease and disrupts their relationships, careers, and perceptions of themselves.

Regulation of alternative splicing of CD45 by antagonistic effects of SR protein splicing factors

CD45 is a transmembrane glycoprotein possessing tyrosine phosphatase activity, which is involved in cell signaling. CD45 is expressed on the surface of most leukocytes and can be alternatively spliced by the inclusion or skipping of three variable exons (4, 5, and 6 or A, B, and C) to produce up to eight isoforms. In T cells, the splicing pattern of CD45 isoforms changes after activation; naive cells express high m.w. isoforms of CD45 which predominantly express exon A (CD45RA), whereas activated cells lose expression of exon A to form low m.w. isoforms of CD45 including CD45RO. Little is known about the specific factors controlling the switch in CD45 splicing which occurs on activation. In this study, we examined the influence of the SR family of splicing factors, which, like CD45, are expressed in tissue-specific patterns and have been shown to modulate the alternative splicing of a variety of transcripts. We show that specific SR proteins have antagonistic effects on CD45 splicing, leading either to exon inclusion or skipping. Furthermore, we were able to demonstrate specific changes in the SR protein expression pattern during T cell activation.

The Breast Health Center at Women & Infants Hospital: origin, philosophy, and features

The Breast Health Center, a component of the program in Women's Oncology at Women & Infants Hospital, is a multidisciplinary center devoted to the treatment and study of benign and malignant breast diseases. The philosophy, structure, and function of The Breast Health Center are described along with its specific components. The Breast Health Center's three fundamental missions of patient care, education, and research are discussed.

Surgical wound morbidity in an austere surgical environment

Surgical wound morbidity was analyzed for a U.S. military field hospital deployed to the Republic of Haiti in support of Operation New Horizons 1998. The purpose of the analysis was to determine if procedures performed in the field hospital had greater infectious risks as a result of the environment compared with historical reports for traditional hospital or clinic settings. Acceptable historical infection rates of 1.5% for clean surgical cases, 7.7% for clean contaminated cases, 15.2% for contaminated cases, and 40% for dirty cases have been noted. There were 827 operations performed during a 6-month period, with the majority of patients assigned American Society of Anesthesiologists Physical Status Classification class I or II. The distribution of these cases was: 72% clean cases, 5% clean contaminated cases, 4% contaminated cases, and 19% dirty cases. The overall wound complication rate was 3.6%, which included 5 wound infections, 11 wound hematomas, 8 superficial wound separations, and 6 seromas. The infectious morbidity for clean cases, the index for evaluation of infectious complications, was 0.8%, well within the accepted standards. There were two major complications that required a return to the operating room: a wound dehiscence with infection in an orchiectomy, and a postoperative hematoma with airway compromise in a subtotal thyroidectomy. There were no surgical mortalities. The infectious wound morbidity for operations performed in the field hospital environment was found to be equivalent to that described for the fixed hospital or clinic settings. No special precautions were necessary to ensure a low infection rate. The safety for patients undergoing elective surgical procedures has been established. Further training using these types of facilities should not be limited based on concerns for surgical wound morbidity.

Development of a comprehensive assessment toolbox for stroke

Comprehensive databases for the assessment of individuals with stroke are essential for clinical management and evaluation of outcomes for quality management and research. The purpose of this article is to describe a comprehensive data system or "toolbox" developed by clinicians and researchers at the Center on Aging at the University of Kansas Medical Center. The choice of assessments for the toolbox resulted from the Agency for Health Care Policy and Research Post-Stroke Rehabilitation Guidelines, results of the Kansas City Stroke Study, and the authors' work to develop a new stroke measure-the Stroke Impact Scale.

The stroke impact scale version 2.0. Evaluation of reliability, validity, and sensitivity to change

BACKGROUND AND PURPOSE

To be useful for clinical research, an outcome measure must be feasible to administer and have sound psychometric attributes, including reliability, validity, and sensitivity to change. This study characterizes the psychometric properties of the Stroke Impact Scale (SIS) Version 2.0.

METHODS

Version 2.0 of the SIS is a self-report measure that includes 64 items and assesses 8 domains (strength, hand function, ADL/IADL, mobility, communication, emotion, memory and thinking, and participation). Subjects with mild and moderate strokes completed the SIS at 1 month (n=91), at 3 months (n=80), and at 6 months after stroke (n=69). Twenty-five subjects had a replicate administration of the SIS 1 week after the 3-month or 6-month test. We evaluated internal consistency and test-retest reliability. The validity of the SIS domains was examined by comparing the SIS to existing stroke measures and by comparing differences in SIS scores across Rankin scale levels. The mixed model procedure was used to evaluate responsiveness of the SIS domain scores to change.

RESULTS

Each of the 8 domains met or approached the standard of 0.9 alpha-coefficient for comparing the same patients across time. The intraclass correlation coefficients for test-retest reliability of SIS domains ranged from 0.70 to 0.92, except for the emotion domain (0.57). When the domains were compared with established outcome measures, the correlations were moderate to strong (0.44 to 0.84). The participation domain was most strongly associated with SF-36 social role function. SIS domain scores discriminated across 4 Rankin levels. SIS domains are responsive to change due to ongoing recovery. Responsiveness to change is affected by stroke severity and time since stroke.

CONCLUSIONS

This new, stroke-specific outcome measure is reliable, valid, and sensitive to change. We are optimistic about the utility of measure. More studies are required to evaluate the SIS in larger and more heterogeneous populations and to evaluate the feasibility and validity of proxy responses for the most severely impaired patients.

Brainstem dysfunction in chiari malformation presenting as profound hypoglycemia: presentation of four cases, review of the literature, and conjecture as to mechanism

OBJECTIVE

We report four patients whose cases resulted in our observation that profound hypoglycemia resulting from intermittent hyperinsulinism plays a significant role in patients with brainstem dysfunction from Chiari I or II malformations who have intermittent autonomic dysfunction ("blue spells").

METHODS

The records of four children with severe brainstem dysfunction associated with hindbrain herniation (Chiari I or II malformation) were reviewed retrospectively. Each patient had severe lower cranial nerve dysfunction that required tracheotomy and feeding tube placement. After we found that profound hypoglycemia had occurred during a spell of autonomic dysfunction in one patient, the charts of the other three patients were reviewed for evidence of hypoglycemia. Now, whenever one of them has evidence of autonomic dysfunction, prospective studies of glucose and insulin levels are performed. Three of the patients had Chiari II malformation in association with myelomeningocele, and one patient had a Chiari I malformation resulting from Pfeiffer's syndrome.

RESULTS

Hypoglycemia occurred in these patients episodically, and usually when their shunts were functioning. The hypoglycemia was associated with hyperinsulinemia in each patient. The brainstem structures of these children (presumably the dorsal motor nuclei of the vagus) were extremely sensitive to changes in local or regional intracranial pressure. These changes were triggered by intermittent shunt failure, agitation from pain, abdominal distention from constipation, and retention of CO2. In patients with Chiari malformations, even mild increases in intracranial pressure lead to brainstem dysfunction. One possible explanation is that pressure on the deformed Xth cranial nerve nuclei may lead to insulin release and life-threatening hypoglycemia. Continuous-drip feeds are necessary to prevent this complication.

CONCLUSION

Patients with severe intermittent brainstem dysfunction after decompression of Chiari I or Chiari II malformations should have laboratory studies of glucose levels performed at the time of the episodes to rule out hypoglycemia.

Motor evoked potentials in a rhesus macaque model of neuro-AIDS

Previous work using bone marrow passaged SIVmac239 (simian immunodeficiency virus) has shown that macrophage tropic strains of this virus enter the rhesus macaque brain early following inoculation (Sharma et al, 1992; Desrosiers et al, 1991; Zhu et al, 1995; and Narayan et al, 1997). As part of an effort to more fully characterize the extent of neurologic impairment associated with SIV infection of the brain, we used transcranial electrical stimulation of motor cortex and the spinal cord to evoke EMG potentials in two forelimb (EDC and APB) and two hindlimb (LG and AH) muscles. The latencies, magnitudes and thresholds of motor evoked potentials (MEPs) recorded from nine monkeys infected with neurovirulent SIVmac R71/17E were compared to pre-inoculation records from the same monkeys. Seven of nine monkeys developed simian AIDS within 4 months of inoculation and were euthanized. Two monkeys remained free of AIDS-related clinical illness for over 18 months following inoculation. Six of the seven monkeys with rapidly progressing disease showed post-inoculation latency increases ( > or = 2 s.d. of control) in at least one cortical MEP. Increases in cortical MEP latency ranged from 21-97% in different monkeys. All seven rapidly progressing animals showed post-inoculation increases in at least one spinal cord MEP latency. Maximum spinal cord MEP latency increases ranged from 22-147%. Increases in central conduction time (CCT) ranged up to 204% and exceeded two standard deviations of control in four monkeys. Neither of the two monkeys with slowly progressing disease showed significant increases in either cortical or spinal cord MEP latency or CCT. Only the monkeys with rapidly progressing disease exhibited classic AIDS-related neuropathology, although there was no consistent relationship between the severity of neuropathology and the extent of MEP abnormalities. In conclusion, our results demonstrate clear deficits in the functional integrity of both central and peripheral motor system structures associated with SIV infection and further support the use of SIV-infected rhesus macaques as a model of neuro-AIDS.

Clear lens extraction with intraocular lens implantation for hyperopia

PURPOSE

Current surgical options for the correction of moderate to severe hyperopia include hyperopic laser in situ keratomileusis (LASIK), phakic intraocular lens implantation and clear lens extraction with intraocular lens (IOL) implantation. We investigate the safety and efficacy of clear lens extraction with IOL implantation to correct hyperopia.

METHODS

Phacoemulsification and IOL implantation was performed on 18 eyes of 10 patients. In 16 eyes, the Hoffer-Q formula was used for IOL power calculation and a single IOL was inserted; in the remaining 2 nanophthalmic eyes, the Holladay-II formula was used and two piggy-back IOLs were inserted.

RESULTS

Mean preoperative spherical equivalent for distance was +6.17 D (range, +4.25 to +9.62 D). Patients were followed postoperatively for a mean of 10.5 months (range, 4 to 27 mo). Uncorrected visual acuity in all eyes was 20/50 or better with a median uncorrected visual acuity of 20/40 (range, 20/30 to 20/50). Two patients lost 2 lines of spectacle-corrected visual acuity; both of these patients achieved spectacle-corrected visual acuity of 20/30.

CONCLUSIONS

Clear lens extraction with IOL implantation is a safe and effective procedure for the correction of moderate to severe hyperopia in the presbyopic age range.

Interpreting age, period and cohort effects in plasma lipids and serum insulin using repeated measures regression analysis: the CARDIA Study

Observed changes in health-related behaviours and disease risk factors may arise from physiological or environmental changes, or from biases due to sampling or measurement errors. We illustrate problems in the interpretation of such changes with longitudinal data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Mean plasma cholesterol was 14 mg/dl higher in 27- than in 20-year-old black men cross-sectionally, but longitudinally it declined by 4 mg/dl during the 7 years. To sort out these contradictory assessments of the effect of age/passage of time, we estimated age and period effects under the assumptions that age effects are a smooth function of age independent of period, and that period effects are changes common to persons across all ages. Simple estimates the age effect, such as the cross-sectional age slopes, may be confounded by cohort effects, by interactions of time and age after baseline, or by the occurrence of non-linearities in response after baseline. We note examples of each potential type of bias. The data and background literature support the assumption that cohort effects do not seriously compromise interpretation for these variables in the CARDIA study. Strong secular decreases in plasma cholesterol, apparently due to population-wide dietary change, mask increases with ageing. Age increases in triglycerides are largely explained by increases in body fatness. For these data, we cautiously accept the cross-sectional age slope as an estimate of ageing and the age-matched time trend as an estimate of secular trend.

Acute intraoperative suprachoroidal haemorrhage in ocular surgery

PURPOSE/BACKGROUND

Acute intraoperative suprachoroidal haemorrhage (AISH) is the most sight-threatening complication of ocular surgery. We investigated the visual outcomes following this intraoperative event, patient characteristics that may predispose to it and the clinical features that may be of prognostic significance.

METHODS

The records of 45 cases of AISH collected from ophthalmic centres in the United Kingdom, Republic of Ireland and Switzerland were reviewed. Two satisfactory controls in terms of operative procedure, surgeon, age (+/- 5 years) and gender were found for each of 33 of our cases. Systemic and ocular characteristics were compared for cases and controls, and the visual results of all cases of AISH are analysed.

RESULTS

Cases and controls differed only in terms of axial length and pre-operative intraocular pressure, both of which were significantly greater for eyes that experienced an AISH (p < 0.05). Ten eyes (22.2%) achieved a final Snellen acuity of 6/12 or better. Statistically significant associations with a final acuity of counting fingers or worse included spontaneous nuclear expression (p = 0.02), retinal detachment (p < 0.0001), four-quadrant suprachoroidal haemorrhage (p = 0.007) and vision of perception of light or worse at the first dressing (p = 0.0001). Four of the 6 eyes that experienced an AISH during phacoemulsification surgery had a visual outcome of 6/12 or better, and this was significantly greater than for cases involving extracapsular cataract surgery (p = 0.004).

CONCLUSION

The results indicate that longer axial length and higher pre-operative intraocular pressure are associated with increased risk of AISH. Poor visual results are more likely following spontaneous nuclear expression, retinal detachment, four-quadrant suprachoroidal haemorrhage or vision of perception of light or worse at the first dressing. The results also suggest that AISH complicating a phacoemulsification procedure has a more favourable visual prognosis than AISH that occurs during extracapsular cataract surgery.

Effects of age on balance assessment using voluntary and involuntary step tasks

BACKGROUND

Taking a step while standing and modifying a step while walking are two strategies often used to maintain balance when balance disturbances are encountered during activities of daily living. This study investigated whether performance on an involuntary step task, which is assumed to be a surrogate for fall recovery abilities, was comparable to performance on a voluntary step task.

METHODS

The performance of a voluntary and an involuntary step task was measured in healthy young adult (mean age 21 years) and healthy elderly adult (mean age 68 years) female subjects. Subjects stepped as fast as possible in the direction of a minimally destabilizing lateral waist pull (voluntary step task), or they responded naturally to a large destabilizing lateral waist pull (involuntary step task). The effects of age, task, and their interaction on the primary outcome variables of step foot liftoff time, landing time, step length, and step height were examined.

RESULTS

In the voluntary step task, the older adults, compared to the young, required significantly more time to lift their foot (Young: 307 msec; Elderly: 424 msec). In the involuntary step task, the elderly were as quick as the young in lifting their foot (Young: 322 msec; Elderly: 335 msec). The young lifted their foot at about the same time for the two tasks. The elders, on the other hand, lifted their foot significantly earlier in the involuntary step task, compared to the voluntary step task (Vol: 424 msec; Invol: 335 msec).

CONCLUSIONS

A voluntary step task underestimates the ability of healthy elderly adults to respond quickly when large destabilizing balance disturbances are encountered.

Sympathetic-parasympathetic interactions at the heart in the anaesthetised rat

This study observed the effects of stimulation of the cardiac sympathetic nerve on vagal slowing of the heart in rats, and compared these with any actions of exogenous neuropeptide Y (NPY) and galanin (GAL). In rats anaesthetised with pentobarbitone, stimulation of the cardiac sympathetic nerve for 2 min at 20 Hz in the rat evoked an attenuation of subsequent cardiac vagal action, which could be mimicked by exogenous NPY, but not GAL. The galanin antagonist, GAL1-13/NPY24-36, known to block the inhibitory action of galanin on the cardiac vagus in cats, did not alter the effect of sympathetic stimulation on cardiac vagal activity. We suggest on the basis of results here that in the rat, NPY released during stimulation of the cardiac sympathetic nerve, causes inhibition of acetylcholine release from the vagus nerve.

Diffusion-weighted magnetic resonance imaging of intracranial epidermoid tumours

Intracranial epidermoids can closely mimic cerebrospinal fluid (CSF) on MRI and CT. Therefore epidermoids can be difficult to detect, or distinguish from CSF. Three cases of intracranial epidermoid are presented, one of which closely mimicked an arachnoid cyst on CT and routine MRI sequences. Diffusion-weighted magnetic resonance imaging (DWI) was performed. All three epidermoids demonstrated marked restriction of diffusion relative to CSF, clearly defining the extent of each lesion, and allowing differentiation from an arachnoid cyst or an enlarged CSF space.