Mechanical consequences of short gastric vessel division at the time of laparoscopic total fundoplication

Laparoscopic Nissen fundoplication is currently the most commonly practiced antireflux operation. Some adverse consequences of the operation remain in the form of mechanical side effects, labeled postfundoplication complaints, of which dysphagia and gas bloat seem to predominate. Measures have been suggested to counteract some of these and one frequently advocated has been division of the short gastric vessels to create a short-floppy wrap. The advantages of this are still debated, particularly in the long-term perspective. The aim of the present study was to evaluate the mechanical consequences of dividing all short gastric vessels at the time of a laparoscopic total fundoplication. Ninety-nine patients with chronic gastroesophageal reflux disease (GERD) were originally allocated on a random basis to have either all short gastric vessels divided or left intact at the time of a laparoscopic total fundoplication. A subsample of these patients, again selected at random, were recruited for a comprehensive manometric investigation 1 year after the operation. In this cohort, 12 patients had all short gastrics divided and in 12 patients, the wrap was done with intact vessels by use of the anterior portion of the fundus. Manometry was carried out by the use of a sleeve sensor to straddle the lower esophageal sphincter (LES), and gastric distension (750 ml air) was used to trigger transient LES relaxations (TLESR). The basal LES tone was similar in the two groups (14.2 ± 2.4 and 18.8 ± 4.3, mean ± SE), respectively. Accordingly, all other relevant manometric variables were equal when the two groups were compared, except for the total number of TLESRs (triggered by gastric distension by air) that were significantly higher (p < 0.02) in patients having their short gastric vessels intact. Consequently, numerically more common cavities were recorded in the latter group. Very similar outcomes in terms of motor function of the LES and esophageal body were observed after a total fundoplication irrespective of whether a complete division of all gastric vessels had been carried out or not. However, after gastric distension with air, more TLESRs were recorded in the latter group suggesting a better maintained ability to vent air from the stomach.     

Vestibular evoked myogenic potentials in acute low-tone sensorineural hearing loss

OBJECTIVE/HYPOTHESIS: It was the authors' premise that the vestibular evoked myogenic potential (VEMP) test may be used to differentiate acute low-tone hearing loss (ALHL) from Meniere's disease with low-tone HL. STUDY DESIGN: Prospective study. METHODS: From January 2000 to December 2002, consecutive 12 patients with ALHL and another 12 patients with definite Meniere's disease with low-tone HL were enrolled in this study. All patients underwent audiometry and VEMP test, before and after treatment with isosorbide for 3 consecutive months. RESULTS: Before treatment, 12 patients with ALHL revealed normal VEMPs (11, 92%) and augmented VEMPs (1). After treatment, 11 (92%) patients had resolved to normal hearing within 3 days. One year later, two (17%) patients progressed to Meniere's disease. In comparison with Meniere's disease, 6 (50%) of 12 patients showed normal VEMPs before treatment, and 7 (58%) patients had their hearing improved 3 months after treatment. Comparison of VEMP responses or hearing outcome between both groups exhibited significant differences. CONCLUSION: Most patients with ALHL reveal normal VEMPs throughout the episode, indicating that the saccule is spared. In contrast, 50% of Meniere's disease patients with low-tone HL demonstrate abnormal VEMPs, showing a significant difference. Therefore, the VEMP test can be used to differentiate ALHL from Meniere's disease with low-tone HL.     

Occupational safety: effects of workplace radiofrequencies on hearing function

BACKGROUND: The effects of radio frequency (RF) and microwave radiation on humans have been the subject of continuous investigation. Clinical investigations related to occupational RF/microwave exposure have been reported by investigators (1). Since one of the major groups occupationally exposed to RF and microwave radiation includes those working in radio broadcasting and TV transmitter stations, this study investigates whether RF affects auditory systems of people exposed to RF. METHODS: The study is carried out with people working in radio broadcasting stations and living in employee residential houses close to the broadcasting stations. All subjects in the control group were similar in age, work regime, socioeconomic status, and lack of experience in working with RF sources. Brainstem Evoked Response Audiometer (BERA) and Pure Tone Audiometry (PTA) were used to measure the effects of RF under investigation on hearing functions of the subjects. In BERA measurements, I-III, III-V and I-V interpeak latencies were evaluated. In pure tone audiometric measurements, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and 8000 Hz frequencies of hearing threshold were measured in subjects of experimental and control groups. Interpeak latencies and bone conduction hearing thresholds of subjects in the experimental group were compared with those of the control group. RESULTS: BERA results showed that I-III, I-V and III-V interpeak latencies of people occupationally exposed to RF were not higher than subjects in control groups (p>0.05). Results of BERA indicated no statistically significant differences between exposure and control subjects. In audiometric evaluation, hearing threshold of people occupationally exposed to RF were found higher than the control group subjects for frequencies of 4000 Hz and 8000 Hz in terms of bone and air conduction of right and left ear (p < 0.01). CONCLUSIONS: The results of traditional audiometer indicated that RF promotes sensorineural hearing loss and affects cochlea parts related to 4000 Hz and 8000 Hz. These findings may have immediate implications and considerations for workplace safety in order to provide an occupationally safe environment to employees working in such settings.     

Discordant mental and physical efforts in an autistic patient

We investigated whether there was mental effort in response to verbal commands in a 16-year old girl with autism, a high degree of non-compliance with commands and symptoms of autonomic dysfunction by monitoring the brainstem autonomic tone during an attempt to perform isometric exercise. An index of cardiac vagal tone (CVT), cardiac sensitivity to baroreflex (CSB), heart rate (HR) and mean arterial blood pressure (MAP) were measured simultaneously. Physical non-compliance with our commands meant there was no force applied by the patient during the attempted exercise, but CVT and CSB were both reduced and sustained at very low levels throughout the attempt, while MAP and HR were increased concurrently to higher levels in the same period. This vagal withdrawal to allow concurrent increases in HR and MAP is an arousal response appropriate for isometric exercise, which is a sign of a positive mental effort to comply with our commands. These results demonstrate discordant mental and physical efforts in our patient. In this particular case, the physical inabilities in some instances could have been mislabelled as mental non-compliance due to autism. It would be worthwhile to investigate the prevalence of discordant mental and physical efforts in autism.     

Atypical autonomic regulation in perpetrators of violent domestic abuse

Perpetrators of domestic violence describe symptoms that are compatible with exaggerated autonomic arousal at the time of the domestic violence. This inappropriate arousal may be reflected in altered heart rate regulation. If heart rate is systematically regulated by vagal mechanisms, then increases in heart rate should correlate with decreases in cardiac vagal activity, as indexed by respiratory sinus arrhythmia (RSA). We hypothesized that perpetrators of domestic violence have an alteration in heart rate regulation. To test this hypothesis we compared the results of a postural shift performed on perpetrators, healthy volunteers, and nonviolent alcoholics. Results showed there were no significant differences in heart rate, RSA, or catecholamines. However, the significant inverse relationship between posture-elicited changes in RSA and heart rate present in the healthy volunteers was not found in perpetrators. These differences in the covariation between heart rate and RSA may represent differences in the neural regulation of heart rate and may be related to difficulties in controlling autonomic state.     

AT1 antagonism by eprosartan lowers heart rate variability and baroreflex gain

INTRODUCTION: Blockade of the renin-angiotensin system (RAS) by ACE inhibitors has been demonstrated to reduce total mortality in cardiovascular diseases. This advantage was attributed in part to changes of autonomic cardiovascular control, exemplified by an increase of heart rate variability (HRV) and baroreflex gain (BRG). We sought to assess the effects of the angiotensin type 1 (AT1) receptor blocker eprosartan on HRV and BRG. MATERIALS AND METHODS: In a double-blind randomized cross-over design 25 young males took eprosartan (600 mg/day) and placebo each for a period of 7 days with a wash-out period of at least 4 weeks in between. At the end of the intake phases simultaneous recordings of arterial blood pressure (AP; Finapres) and electrocardiogram (ECG) were taken. Power spectra of HRV and arterial blood pressure variability (APV) were calculated by fast Fourier transform (FFT) and served to calculate BRG. Ang-II levels were measured by radioimmunoassay. RESULTS: Eprosartan tended to lower mean AP, it slightly increased heart rate (HR) (p<0.05), and markedly increased circulating Ang-II levels (p<0.01). Eprosartan diminished the total power of HRV (p<0.05) and the BRG (p<0.01). The low/high frequency (LF/HF) ratio of HRV and the APV were not altered. CONCLUSIONS: AT1 antagonism by eprosartan lowers heart rate variability and baroreflex gain. We speculate that these findings are due to the marked increase in circulating angiotensin II (Ang II). Further studies are needed to clarify whether angiotensin type 1 (AT1) blockers with potential actions inside the blood-brain barrier (BBB) may have different effects on HRV and BRG.     

Venous dilator effect of apelin,an endogenous peptide ligand for the orphan APJ receptor,in conscious rats

Apelin is an endogenous depressor peptide for the G protein-coupled APJ receptor. Our hypothesis is that apelin is a venodilator, and it reduces mean circulatory filling pressure (MCFP; index of venous tone). Dose–response curves of apelin (10, 20 and 40 nmol/kg) or vehicle (0.9% NaCl) were constructed in two groups each of conscious, unrestrained rats: unblocked rats and rats pretreated with mecamylamine (Mec; ganglionic blocker) and noradrenaline (NA; to restore vascular tone). The vehicle had no effects in the unblocked or ganglionic-blocked rats. Apelin decreased mean arterial pressure (MAP) and increased heart rate (HR), but it did not alter mean circulatory filling pressure in the unblocked rats. In the ganglionic-blocked rats, apelin did not alter heart rate but decreased mean arterial pressure and mean circulatory filling pressure. These results show that apelin is an arterial and venous dilator in vivo. The depressor effect of apelin is accompanied by tachycardia which is abolished by ganglion blockade.     

Topical phenylephrine increases anal canal resting pressure in patients with faecal incontinence

INTRODUCTION: The internal anal sphincter receives a stimulatory alpha(1) adrenergic innervation. Use of an adrenergic agonist may therefore have a role in treating patients with faecal incontinence. METHODS: Ten patients (seven females, median age 66 years) with passive faecal incontinence related to weak internal anal sphincter were studied. All patients had intact anal sphincters as assessed by endoanal ultrasound. Phenylephrine gel was applied in a double blind manner in concentrations of 0%, 10%, 20%, 30%, and 40% (Slaco Pharma (UK) Ltd, Watford, UK) on separate days. Maximum resting anal pressure (MRP), anodermal blood flow, blood pressure, and pulse rate were measured before, and one and two hours after application. RESULTS: All concentrations of phenylephrine gel increased median MRP (43, 48, 54, 65, and 70 cm H(2)O, for placebo, 10% (p=0.122), 20% (p=0.170), 30% (p=0.002), and 40% (p=0.004), respectively at one hour; comparisons with placebo). This was sustained at two hours. There was a clear dose-response relationship at one hour. Higher concentrations raised median MRP to within the normal range (> 60 cm H(2)O). At two hours, all concentrations greater than 20% increased the pressure to a similar degree, suggesting that the exact concentration may be important for the initial effect but given a certain threshold is less important after a period of time. Toxicity was rare. Two patients experienced transient perianal burning which settled within a few minutes. There was no significant effect on anodermal blood flow, blood pressure, or pulse rate. CONCLUSION: This study has demonstrated the feasibility of using topical phenylephrine to raise resting anal tone in patients with faecal incontinence. Randomised controlled trials are required to assess the efficacy of this agent.     

Mapping responses to frequency sweeps and tones in the inferior colliculus of house mice

In auditory maps of the primary auditory cortex, neural response properties are arranged in a systematic way over the cortical surface. As in the visual system, such maps may play a critical role in the representation of sounds for perception and cognition. By recording from single neurons in the central nucleus of the inferior colliculus (ICC) of the mouse, we present the first evidence for spatial organizations of parameters of frequency sweeps (sweep speed, upward/downward sweep direction) and of whole-field tone response patterns together with a map of frequency tuning curve shape. The maps of sweep speed, tone response patterns and tuning curve shape are concentrically arranged on frequency band laminae of the ICC with the representation of slow speeds, build up response types and sharp tuning mainly in the centre of a lamina, and all (including high) speeds, phasic response types and broad tuning mainly in the periphery. Representation of sweep direction shows preferences for upward sweeps medially and laterally and downward sweeps mainly centrally in the ICC (either striped or concentric map). These maps are compatible with the idea of a gradient of decreasing inhibition from the centre to the periphery of the ICC and by gradients of intrinsic neuronal properties (onset or sustained responding). The maps in the inferior colliculus compare favourably with corresponding maps in the primary auditory cortex, and we show how the maps of sweep speed and direction selectivity of the primary auditory cortex could be derived from the here-found maps of the inferior colliculus.     

Vasomotor effects of L- and D-arginine in stenotic atheromatous coronary plaque

OBJECTIVE—To examine the effects of exogenous L- and D-arginine on coronary stenosis vasomotion in relation to stenosis morphology.
DESIGN—Intracoronary infusions of normal saline, L- and D-arginine (50 and 150 µmol/min), and glyceryl trinitrate (250 µg bolus) were given in 24 patients with coronary artery disease and stable angina. Coronary stenoses were classified as smooth or complex (irregular borders). The diameter of the coronary stenoses and their adjacent reference segments was measured by computed quantitative angiography.
RESULTS—During L-arginine infusion a larger proportion of complex stenoses than smooth stenoses dilated by ⩾ 10% (p < 0.01), and the magnitude of dilatation was greater at the site of complex stenoses (p < 0.05). Irrespective of the type of morphology there was a positive correlation (p < 0.01) between the severity of stenoses and the magnitude of vasodilatation to L-arginine. The response to glyceryl trinitrate was similar in the two groups. No significant change was found in either group in response to D-arginine.
CONCLUSIONS—In patients with coronary artery disease, coronary stenoses—particularly those of complex morphology—dilate in response to the administration of L-arginine but not D-arginine. This finding is consistent with partial deficiency of the substrate for nitric oxide synthesis, L-arginine, at the site of complex stenoses.