Physiology and pathophysiology of skeletal muscle contractions

An overview is presented of the physiology and pathophysiology of dynamic skeletal muscle contractions in the intact living organism. Dynamic muscle activities are divided into concentric contractions with shortening of muscle fibres and the production of positive work, and eccentric contractions with lengthening of muscle fibres and the production of negative work. In positive work, muscle tension overcomes external forces. In negative work, external forces overcome muscle tension. The latter phenomenon, with relatively few active motor units, explains the injuries induced by eccentric contractions. Both the contractile and non-contractile elements are involved in the muscle injuries and, clinically, they are referred to as myofibrositis.     

METOPROLOL DECREASES THE AMOUNT OF HALOTHANE REQUIRED TO INDUCE HYPOTENSION DURING GENERAL ANAESTHESIA

A double-blind, randomized and placebo-controlled study wasundertaken to assess the effects of metoprolol on controlledhypotension during halothane anaesthesia. Nineteen patientsundergoing middle ear or nasal septum surgery were studied.The aim was to achieve a 25% reduction of the mean arterialpressure in both groups. Metoprolol was given by mouth on twooccasions in the 10–12 h before operation. In the grouppretreated with metoprolol the halothane concentration was reducedby 35.5%. The duration of bleeding and its degree were reducedsignificantly. The time to awakening was shorter and of betterquality after pretreatment with metoprolol. Rate-pressure productwas less after pretreatment with and rebound hypertension waswell controlled.     

The effect of naloxone on the preoperative gastric volume and pH

The effect of 4 mg oral naloxone on preoperative gastric volume and pH of gastric aspirate was studied in a double-blind, randomized study. Twenty patients received 10 ml of naloxone (4 mg) mixed with 10 ml of orange juice, and 20 patients received 10 ml of isotonic saline mixed with 10 ml of orange juice, 2 h before surgery. Gastric content was obtained immediately after intubation of the trachea. No significant difference in gastric volume and pH of gastric aspirate was found between the two groups. It is concluded that naloxone does not affect gastric emptying and gastric acid secretion to a degree great enough to protect against aspiration of gastric contents into the lungs.     

Pharmacotherapy for aggressive and violent behaviour: A view of practical management from clinicians

Within psychiatric populations, when violent behaviour occurs it is generally at least partly attributable to the psychiatric condition. The treatment therefore most likely to be successful in modifying the violent behaviour is that most appropriate for the underlying condition, and much may be achieved in calming aggressive behaviour without using any medication at all. No drug is a specific ‘treatment’ for violence. In situations of acute crisis, however, short-term control of violent behaviour is often achieved most speedily and effectively when medication is included in the treatment approach. The drugs best fitted for such purposes have calming qualities. Neuroleptics are generally among the first to be used, followed by barbiturates or benzodiazepines. The power of the way in which such drugs are administered; for example, in the timing, route of delivery or form of preparation is often underestimated. In particular, the potential value of depot neuroleptics of intermediate duration of action is discussed. Longer-term control of violence term of such drugs as the mood stabiliser lithium, anticonvulsants (including carbarnazepine), other sedatives and beta blockers is also discussed.     

Acute Myocarditis

ABSTRACT In a prospective study, 57 patients with a preliminary diagnosis of myocarditis were investigated. Twenty-four patients were considered to have an acute myocarditis, 14 had a suspected myocarditis, while in 19 patients myocarditis was excluded. Episodes of frequent supraventricular and/or ventricular extrasystoles during hospital stay were seen in 8/24 cases (33%) with myocarditis and in 1/19 cases (5%) without myocarditis. On follow-up 1 month later, no supraventricular extrasystoles were observed in either group. Echocardiographic signs consistent with left ventricular insufficiency were noted in 7/24 cases (29%) with myocarditis, in 1/14 cases (7%) with suspected myocarditis and in no case without myocarditis. With a “routine” serologic test battery covering influenza viruses A and B, adenovirus, Coxsackie virus group B, ECHO viruses, Chlamydia psittaci, Mycoplasma pneumoniae and hemolytic streptococci group A, a possible etiology could be documented in 9/24 cases (38%) with myocarditis and in 4/19 cases (21%) without myocarditis. Enterovirus-specific IgM was detected with solid-phase reverse immunosorbent test (SPRIST) in 12/23 (48%) cases with myocarditis and in 3/16 cases (19%) without myocarditis. In SPRIST-IgM-positive cases, IgM antibodies were detected in 15/20 (75%) of the sera taken on admission. The overall serological results indicated a recent infection in 16/24 cases (67%) with myocarditis and in 5/19 cases (26%) without myocarditis (p < 0.05).     

Malignant Warthin''s tumour: a case study

Malignant transformation of a benign Warthin's tumour (adenolymphoma) is extremely rare. The light microscopic and ultrastructural features of an adenocarcinoma arising in a Warthin's tumour in the parotid gland are described. Light microscopy demonstrated a transition zone from the benign to the malignant component, and the malignant cells revealed oncocytic features by both light- and electronmicroscopy.     

Bilateral masseteric contractile activity in unilateral gum chewing: differential calculus

SUMMARY Twelve healthy subjects performed 10 s, 15 s, 20 s, and 25 s of right-sided and, subsequently, left-sided gum chewing. The contractile activities of the ipsilateral (chewing side) and contralateral (non-chewing side) masseter muscles, mainly the concentric contractions of the phase of jaw closing and the isometric contractions of the phase of dental occlusion, were recorded through cumulative surface electromyography (EMG). A linear function (y = ax + b) described the association between an increase in the duration (x) of unilateral gum chewing and the cumulative EMG (y) of both the ipsilateral and the contralateral masseter muscle, and because of different slopes (a) of the two straight lines a geometric function (y = aqx) described the progressively larger differences between the paired and straight lines. When differential calculus was applied to the exponential functions, it became evident that the chewing forces generated by the ipsilateral masseter muscle continually exceeded those generated by the contralateral masseter muscle, and that the positive work (force x distance) produced by the concentric contractions of the ipsilateral masseter muscle continually exceeded that produced by the concentric contractions of the contralateral masseter muscle. It was inferred that mechanophysical work plays a major role if clinical muscle fatigue develops during prolonged unilateral gum chewing.     

Met and unmet nursing care needs in men with prostate cancer. An explorative study. Part II

Men with prostate cancer ( n = 11) were interviewed during an in-patient period at a urological clinic, about their experiences of met and unmet needs from health professionals. Their perception of quality of life and sense of coherence were also assessed. The findings were analysed from a phenemenological-hermeneutic perspective and interpreted within the concept of transition. It was interpreted that objective functional health needs were mostly met by health professionals and subjective existential needs were mostly not met. The analysis revealed patients as passive or active receivers of care. Passive receivers were explicitly and implicitly stating unmet needs, or explicitly stating satisfaction with nursing care at the same time as implicitly contradicting, referring to their needs as bagatelles, unimportant, whereas active receivers talked about their needs explicitly with the staff and did not state implicit unmet needs. This suggests that nurses need to be aware of and have sensitive ears to undertones in statements and actively seek for patients' needs. The most important nursing care areas seemed to be to provide solutions to physical problems together with staff support including information, and acting to increase confidence in staff and staff availability. This encourages patients, wives and families, in co-operation, towards a healthy exit of transition.     

Thoracic epidural analgesia in aortocoronary bypass surgery II: effects on the endocrine metabolic response

Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may – in part – be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS).
Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 μg–kg^-1) anaesthesia, the HF + TEA group with the same fentanyl dose + TEA with 10 ml bupivacain 5 mg ml^-1, followed by 4 ml every hour, and the LF + TEA group receiving fentanyl 15 μg kg^-1 + TEA. Adrenalin, noradrenalin, systemic vascular resistance (SVR), glucose, Cortisol, lactate and free fatty acids were followed during the operation and for 20 h postoperatively.
A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and Cortisol was noticed in all groups, but the increase was delayed in the epidural groups.
Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone.