Dragan Pavlovic

Histological changes in masticatory muscles of mdx mice

OBJECTIVE Duchenne muscular dystrophy (DMD) patients have distorted dentofacial morphology that could be a result of changed force balance of masticatory muscles due to unequal dystrophic changes in various masticatory muscles. Skeletal muscles of DMD patients and those of murine model of DMD - mdx mice - are both characterized by Ca(2+) induced muscle damage, muscle weakness and characteristic histological changes. Therefore, to determine the pathological changes in this animal model of DMD, we examined the masticatory muscles of the mdx mice for histological abnormalities including nuclei localization, fibre diameters, and collagen expression. DESIGN Muscle sections from masseter (MAS), temporal (TEM), tongue (TON) and soleus (SOL) of mdx and control normal mice were stained with hemalaun/eosin or with Sirius Red and morphometrically analysed. Levels of collagen staining in normal and mdx muscles were measured using image analysis and the mean optical density (mod) was determined. RESULTS Dystrophin deficient masticatory muscles contained 11-75% fibres with centralised nuclei. In mdx mice an increased mean fibre diameter was observed as compared to the age-matched control muscles (control vs. mdx; MAS: 33.44+/-0.49microm vs. 37.76+/-0.68microm, p<0.005; TEM: 32.93+/-0.4microm vs. 42.93+/-0.68microm, p<0.005; SOL: 33.15+/-0.29microm vs. 40.62+/-0.55microm, p<0.005; TON: 13.44+/-0.68microm vs. 15.63+/-0.18microm, p<0.005). Increased expression of collagen was found in MAS (mod control vs. mdx: 1.34 vs. 3.99, p<0.005), TEM (mod control vs. mdx: 3.11 vs. 4.73, p<0.01) and SOL (mod control vs. mdx: 2.36 vs. 3.49, p<0.01). CONCLUSION Our findings revealed that mdx masticatory muscles are unequally affected by the disease process. The masticatory muscles of the mdx mice could present a useful model for further investigating the influence of dystrophin deficiency on muscles function.

Increased oxidative stress in dystrophin deficient (mdx) mice masticatory muscles.

BACKGROUND It has been suggested that increased oxidative stress and the glutathione antioxidant system play an important role in the pathogenesis of Duchenne muscular dystrophy. However, there is still a lack of data about the oxidative status in dystrophic masticatory muscles. METHODS In the masticatory muscles of the mouse model of Duchenne muscular dystrophy (mdx and controls; 100 days old, n=8-10 each group) we examined the GSH and GSSG content (glutathione reduced/oxidized form) and the level of lipid peroxidation (LPO) as measured by the thiobarbituric acid-reaction. RESULTS In the mdx mice masticatory muscles we found increased oxidative stress as compared to the controls. The GSH values in mdx muscles were decreased (mean±SEM; masseter 339.8±37.6 μg/g vs. 523.1±36.1 μg/g, temporal 304.1±49.6 μg/g vs.512.6±60.6 μg/g, tongue muscle 243.3±28. 8 μg/g vs. 474.9±40.1 μg/g; Fig. 1) as compared to normal mice. The GSH/GSSG ratio in mdx mice was consequently decreased. No significant differences in GSSG content and LPO levels were found between mdx and control mice. CONCLUSIONS The results imply that oxidative stress is present in all three studied mdx mouse masticatory muscles.

Acupuncture for persistent postoperative hiccup.

denied a history of gastro-oesophageal reflux. Assessment of her airway revealed a Mallampati score of 3, a thyromental distance of 6 cm and mouth opening of 3 cm. The patient consented to a supra-clavicular brachial plexus block, but insisted on a general anaesthetic. The potential risks of airway difficulties were explained. Following pre-oxygenation and intravenous induction of general anaesthesia, facemask ventilation with an oropharyngeal airway was found to be extremely difficult: Han scale 3 [1]. The patient’s oxygen saturation fell rapidly. A size 4 PLMA was inserted easily with digital technique, but ventilation was not possible. A size 4 cLMA was inserted using a digital method, with the same result. Rescue face mask ventilation was again difficult and the best oxygen saturation achieved was 89%. A size 4 i-gel was then inserted without difficulty. This immediately provided unobstructed ventilation and stable oxygen saturation of 98%. Intermittent positive pressure ventilation produced good ventilation and peak airway pressures of 25 cmH2O for the remainder of the case. The i-gel is currently under evaluation in our hospital, hence its availability. This case illustrates a potential role for the device in airway rescue, where difficult ventilation is encountered, and other more established supraglottic airway devices have failed. Of note, when this case was discussed locally, two other anaesthetists in our department reported other cases where the i-gel had been placed after failure of placement of cLMA, PLMA or both. Both the cLMA [2] and PLMA may rescue the obstructed airway [3] with high levels of success. However it is not surprising that one supraglottic airway device will not always succeed, and there are cases of PLMA success after cLMA failure [4, 5] and the reverse [3, 6]. It is notable that the i-gel is gaining a reputation for ease of insertion [7, 8]. There is also one previous case of airway rescue and tracheal intubation reported with the i-gel [9]. The i-gel’s role in difficult airway management remains to be established but its ease of insertion, short wide airway tube and good airway leak pressures make it a potentially useful airway rescue device in cases of difficult mask ventilation.

Millimetre wave therapy for pain relief after total knee arthroplasty: A randomised controlled trial

Millimetre wave therapy (MWT) is a promising complementary method for pain relief, however rigorous investigations of its effectiveness are needed. The purpose of this study was to examine if MWT can reduce opioid requirement compared to sham procedure applied for relief of acute pain in patients after total knee arthroplasty (TKA). Eighty patients undergoing TKA were randomly assigned to receive MWT or sham procedure. Patients and evaluators were blinded to the group allocation. MWT consisted of six sessions, each session of 30min duration. During each session the knee wound was exposed to electromagnetic waves with frequency 50–75GHz and power density 4.2mW/cm2. Postoperative analgesia with piritramide, a weak opioid with 0.7 potency of morphine delivered via patient‐controlled analgesia pump, was directed to achieve pain intensity of less than 40 on a 100mm visual analogue scale (VAS). The primary outcome measure was postoperative piritramide requirement for three days after surgery. Secondary outcome measures were: total ibuprofen requirement from the fourth postoperative day to discharge; success of patients’ blinding; patients’ satisfaction with pain relief; incidence of analgesia‐related side effects; heart rate and blood pressure. Piritramide requirement was similar in both groups whereby all patients reported adequate pain relief measured on a VAS. Secondary outcome measures were also comparable in both groups. The majority of patients in both groups believed they had received true MWT and wanted to repeat it in future. Millimetre waves applied to surfaces of surgical wounds did not reduce opioid requirement compared to the sham procedure after TKA.

The expression of myogenic regulatory factors and muscle growth factors in the masticatory muscles of dystrophin-deficient (MDX) mice

The activities of myogenic regulatory factors (MRF) and muscle growth factors increase in muscle that is undergoing regeneration, and may correspond to some specific changes. Little is known about the role of MRFs in masticatory muscles in mdx mice (the model of Duchenne muscular dystrophy) and particularly about their mRNA expression during the process of muscle regeneration. Using Taqman RT-PCR, we examined the mRNA expression of the MRFs myogenin and MyoD1 (myogenic differentiation 1), and of the muscle growth factors myostatin, IGF1 (insulin-like growth factor) and MGF (mechanogrowth factor) in the masseter, temporal and tongue masticatory muscles of mdx mice (n = 6 to 10 per group). The myogenin mRNA expression in the mdx masseter and temporal muscle was found to have increased (P < 0.05), whereas the myostatin mRNA expressions in the mdx masseter (P < 0.005) and tongue (P < 0.05) were found to have diminished compared to those for the controls. The IGF and MGF mRNA amounts in the mdx mice remained unchanged. Inside the mdx animal group, gender-related differences in the mRNA expressions were also found. A higher mRNA expression of myogenin and MyoD1 in the mdx massterer and temporal muscles was found in females in comparison to males, and the level of myostatin was higher in the masseter and tongue muscle (P < 0.001 for all comparisons). Similar gender-related differences were also found within the control groups. This study reveals the intermuscular differences in the mRNA expression pattern of myogenin and myostatin in mdx mice. The existence of these differences implies that dystrophinopathy affects the skeletal muscles differentially. The finding of gender-related differences in the mRNA expression of the examined factors may indicate the importance of hormonal influences on muscle regeneration.

On ears and Head

The original empirical conjecture of auricular acupuncture (AA) consists of a claim that the entire human body is represented in a certain way on the auricle (eg, in the form of an inverted fetus, see figure 1A), and that the pathology of human organs leads to specific changes at these respective areas on the auricle. It is claimed that these changes can be identified as the areas with skin discolourations, which are tender on palpation. Moreover, the stimulation of these auricular areas, which are supposed to somehow be connected to the organ with ‘pathology’, is believed to improve the functioning of the impaired organ or relieve the related pain.1 The representation of the human body on the auricle is often called ‘somatotopic’, analogous to motor and sensory somatotops of precentral and postcentral gyri of the cortex, as described by Penfield and Rasmussen on the basis of experimental research.2 Interestingly, randomised clinical trials on the efficacy of AA have demonstrated that stimulation of the areas of auricle according to the AA empirical conjecture was effective as complementary treatment for a variety of pain syndromes and preoperative anxiety.3,–,5 However, no neuroanatomical pathways are known to connect the ‘diseased’ organs with the external auricle so that the observed phenomena cannot be explained by the underlying anatomy. Figure 1 (A) The empirical conjecture of auricular acupuncture claims that the entire human body is represented on the auricle in the form of an inverted fetus. (B) Innervation pattern of external auricle. Concha and triangular fossa of the pinna are innervated by the branches of trigeminal and vagal nerves, whereas the peripheral regions of the auricle—helix and scapha—receive their nerve supply …

Capnography vs. bronchoscopy for percutaneous tracheostomy placement.

I read the letter regarding the impending collapse of academic anaesthesia with considerable interest (Jackson et al. Anaesthesia 2003; 58: 911–2). As I am a clinical anaesthetist who does quite a bit of research ‘on the side’, I feel I can speak with a certain amount of authority on the issues raised, and perhaps suggest alternative solutions to the rather drastic measures proposed. In any case, their proposals are, in my view, impractical and unlikely to improve the lot of academic departments. There is no doubt that clinical academic departments in all specialties are suffering as a result of changes in funding, training, and the focus of Universities. There is also no doubt that anaesthesia has suffered disproportionately. One does not have to look very far to see why. The collective perception of research by anaesthetists themselves must take some of the blame. The following views are repeatedly expressed to me: 1 Anaesthesia is a service speciality and doesn’t have time for research 2 Anaesthesia is very safe and cannot be improved upon, so clinical research is pointless 3 Basic science is too difficult for anaesthetists to understand 4 Trainees have no interest in research, and in any case it is no longer a career issue. I will deal with each of these in turn. If you think of yourself as a servant, you will be treated as a servant. There is no doubt that the more assertive approach in recent years by the Royal College of Anaesthetists and the Association of Anaesthetists has vastly improved ‘in-theatre’ standards. Trivial operations are no longer performed at bizarre times of night, and consultant cover for trainees has improved beyond recognition in the past 20 years. Nevertheless, Trusts view anaesthetists simply as a means to an end – getting the patients to lie still long enough for the surgeon to perform the operation and thereby reduce the waiting lists. If we offer ourselves up merely as ‘bums on seats’, and perform no other extracurricular activity apart from occasional College activities, we can hardly expect our peers, the local hospital management, major research-funding bodies, or even the Government, to take much notice of what we say. ‘Nobody asked the anaesthetists’ is a frequent complaint. The current controversy surrounding the means of insertion of central lines is a good example. Did anyone from NICE ask you what you thought about it? We only have ourselves to blame. Anaesthesia of itself causes very little major morbidity or mortality in this country. However, in my view, this does not mean we can sit back and let the surgeons take all the blame, tempting as that may be. I have attended several national surgical meetings, and it always strikes me that the surgeons are continually frustrated by complex perioperative issues that limit the type of patient that can undergo a particular operation, and ⁄ or affect outcome. By this I mean such things as nutritional status, preand postoperative fluid balance, pulmonary embolus, wound infection and dehiscence, and MRSA to name but a few. You may think surgeons are a law unto themselves and should sort out their own problems, but I would contend that we are all professionals who have a collective responsibility for the welfare of any patient that we take to theatre. We need to work out how to provide the most relevant pre-operative care, how to maximise intra-operative management, and how to speed their recovery. We are part of the team that brought them into hospital. We have an obligation to get them out., The excuse that basic science is too difficult for anaesthetists to understand is put to me very frequently, and is possibly the scariest. With a very few notable exceptions, the majority of anaesthetic Specialist Registrars are convinced that science is an impenetrable jungle. Many of their consultant colleagues express similar views. In these attitudes, we are no better than the general public. The standard of scientific knowledge and understanding in this country is a national disgrace. Why are we following this herd? Medical schools recruit people with the highest science A-level grades in the country. We need to find out what happens next that turns these bright young people into trainees that are happy to give potent vasopressors without having the faintest idea how they work. Jackson et al. are quite right that we are in danger of turning

Acupuncture does not influence brainstem auditory evoked potentials: a volunteer crossover study

Background Although acupuncture is effective for treating several conditions, its site specificity is questionable. Objective To investigate whether acupuncture influences the brainstem auditory evoked potentials (BAEP). Methods 10 healthy volunteers were enrolled according to inclusion criteria. One of four acupuncture points—TE3, GB43 (both auditory system-specific, according to traditional Chinese medicine) and non-specific acupuncture points HT7 and ST44—was needled during each session. Each volunteer received four sessions of acupuncture, with a 1-week interval between the sessions. Results Peak latencies and amplitudes of the BAEP were registered before and during each session of acupuncture. Pain intensity and the incidence of paraesthesia (Qi sensation) during acupuncture were also registered. The peak latencies and amplitudes of the BAEP registered during acupuncture had not changed from the baseline levels. Needling of acupoint HT7 was most painful and induced the maximal incidence of Qi sensation. Conclusions Findings suggest that monitoring the BAEP is not a suitable technique for studying the immediate effects of acupuncture.

Impact of lipid modulation on the intestinal microcirculation in experimental sepsis

It has been observed, that patients who were treated medically for dyslipoproteinemia had a potentially lower risk of complications during infection and sepsis, regarding both morbidity and mortality. Aim of this study in experimental sepsis was to elucidate the impact of lipid metabolism modulation by simvastatin, HDL, or bezafibrate, respectively, on the intestinal microcirculation which plays a crucial role in the development of multiple organ failure in sepsis. Experimental sepsis was induced in Lewis rats by intravenous lipopolysaccharide (LPS) administration. Animals were treated with simvastatin, HDL or bezafibrate. By means of intestinal intravital microscopy (IVM), the inflammatory response in the microcirculation was studied by leukocyte adherence assessment (LA) and functional capillary density (FCD) measurements. In addition, plasma levels of pro-inflammatory cytokines were determined. Bezafibrate treatment led to a reduction in leukocyte adherence, improved functional capillary density (FCD), and a reduction in interleukin-1α (IL-1α), tumour necrosis factor α (TNF-α) and granulocyte macrophage colony stimulating factors (GM-CSF) plasma levels in experimental sepsis. Contrary to this, the administration of HDL increased leukocyte adherence as well as the number of rolling leukocytes. Only IL-1α plasma levels were decreased by HDL. No significant changes were observed following simvastatin treatment. In summary, only bezafibrate showed anti-inflammatory effects in endotoxemia. This effect cannot be explained by the HDL-enhancing effect of the bezafibrate, since the direct administration of HDL showed opposite effects. Bezafibrate induced reduction of inflammation in sepsis should be investigated in further studies.

Impact of insulin on the intestinal microcirculation in a model of sepsis-related hyperglycemia

BACKGROUND Sepsis involves dysfunctional glucose metabolism. Among patients with sepsis, hyperglycemia is frequent and insulin administration has been evaluated for glycemic control to improve patient outcomes. Only few studies have examined the hyperglycemic microcirculation and the impact of insulin on the microvasculature in sepsis. OBJECTIVE To study the functional capillary density (FCD) and leukocyte activation within the intestinal microcirculation in endotoxin-induced experimental sepsis. METHODS In 50 male Lewis rats, endotoxemia was induced with lipopolysaccharide (LPS; 5 mg/kg). Low dose (LD) glucose was administered to avoid insulin-induced hypoglycemia. High dose (HD) glucose was administered to model sepsis-related hyperglycemia. Animals in LD and HD glucose groups received an insulin bolus (1.4 IU/kg). Two hours after LPS administration, intravital microscopy (IVM) of the terminal ileum was performed, and FCD and leukocyte adherence were measured in a blinded fashion. Blood glucose levels were measured every 30 min following the onset of endotoxemia. Plasma samples were collected 3 h after the onset of endotoxemia to measure IFN-γ, TNF-α, IL-1α, IL-4, GM-CSF and MCP-1 levels using multiplex bead immunoassay. RESULTS Endotoxemia significantly reduced FCD and increased leukocyte adherence within the intestinal microvasculature. LD and HD glucose administration combined with insulin improved the FCD and decreased the adherence of leukocytes in endotoxemic animals as did HD glucose administration alone. Consistent with these results, IL-4, IL-1α, GM-CSF and IFN-γ levels were decreased following combined HD glucose and insulin administration in endotoxemic animals. CONCLUSIONS Insulin administration, as well as an endogenous insulin response triggered by HD glucose administration, improved the FCD and decreased leukocyte activation in endotoxemic rats. The results of this study give insight into the immune and vaso-modulatory role of insulin administration during experimental endotoxemia, and may be extrapolated for clinical sepsis and other critical illnesses with marked microcirculatory dysfunction.