Cardiovascular risk factors in Inuit of Greenland

BACKGROUND

Mortality from ischaemic heart disease (IHD) and prevalence of coronary arteriosclerosis are low in Inuit of Greenland (Greenlanders). Aetiological considerations have so far focused mostly on diet and blood lipids. The present study is a comprehensive analysis of behavioural, clinical and serological cardiovascular risk factors for IHD in Greenlanders.

METHODS

An interview survey from West Greenland (n = 1436) was supplemented with clinical measurements and blood sampling in selected towns and villages (n = 264).

RESULTS

The average consumption of marine mammals and fish was 28 meals per month. In Greenland 14% of males and 30% of females were physically inactive compared with 14% and 17% in the general population of Denmark; 79% were current smokers and 22% smoked 15+ cigarettes per day compared with 42% and 21% in Denmark. High density lipoprotein (HDL) concentration was 1.6 mmol/l in Greenland (1.1 in Denmark) and triglyceride concentration 1.0 mmol/l (1.5). Obesity, blood pressure and total cholesterol were similar in Greenland and Denmark. There were significant differences between Greenlanders with a predominantly traditional childhood and those with a more westernized childhood with regard to diet, physical activity (in women) and blood lipids.

CONCLUSIONS

In spite of an increased westernization of the Greenlanders' lifestyle and a high prevalence of several cardiovascular risk factors, mortality from IHD is still low. The change in risk factor patterns is, however, recent and an increased IHD mortality is still to be expected. Preventive measures should be initiated to reduce risk factors but they must take into consideration possible negative consequences of e.g. traditional outdoor activities and the consumption of marine mammals.

Parameters influencing potency of Bacillus thuringiensis var. israelensis products

Bioassays of products based on Bacillus thuringiensis var. israelensis have been carried out according to standard protocols. These analyses revealed that the slopes of the log-probit transformed concentration mortality curves of various products were different from that of the international standards (IPS82 for B. thuringiensis israelensis). For statistical reasons, this invalidates the tests. Products giving various slopes of the concentration mortality curves will obtain different potencies when estimated at a LC90 level than when estimated at LC50 level, as normally done. The LC90 level is probably more relevant for the field effect. Changing the median particle size of a product in a non destructive way results in change of slope and LC50 and thereby potency. Therefore, potency of a product as measured in these bioassays is not just a measure of the quantity of B. thuringiensis israelensis crystal protein present, but a function of product parameters like median particle size. Biochemical methods for quantification of toxin can therefore not relate simply to potency of the products obtained with this method. It is suggested that standard protocols for bioassay may be changed to assure equal particle size of products and samples to obtain parallel dose response.

Anthropometric variables as predictors for duration of action of atracurium-induced neuromuscular block

Reports concerning duration of action of atracurium in obese patients are conflicting. The aim of this study was to evaluate different anthropometric variables as predictors for duration of action of atracurium-induced block. We studied 127 female patients (total body weight 46-119 kg) anesthetized with midazolam, fentanyl, thiopental, nitrous oxide, and halothane. Twelve different anthropometric variables were evaluated as predictors for duration of action. Linear, least-square, regression analyses were used. There was a significant correlation between each of the 12 variables and the duration of action. The predictors with the greatest correlation coefficients for duration of action of the atracurium induction dose (0.5 mg/kg) were total body weight divided by surface area (r2 = 0.284, P < 0.0001), body mass index (r2 = 0.265, P < 0.0001), and total body weight (r2 = 0.264, P < 0.0001). The most significant predictors for the duration of action of the first supplemental atracurium dose (0.15 mg/kg) were total body weight divided by surface area (r2 = 0.170, P < 0.0001) and total body weight (r2 = 0.160, P < 0.0001). We propose that the atracurium dose should be reduced with 0.23 mg for each kilogram of total body weight above 70 kg. We conclude that the duration of action of atracurium block is prolonged in obese patients, and that atracurium dose in milligrams per kilogram of total body weight should be reduced in these patients. Total body weight divided by the surface area and total body weight were the best predictors for duration of action of atracurium-induced neuromuscular block.

Optimum time for neostigmine reversal of atracurium-induced neuromuscular blockade

PURPOSE

The aim of the study was to determine the optimum time for administration of neostigmine during recovery from atracurium-induced neuromuscular blockade.

METHODS

The study comprised 103 patients anaesthetised with midazolam, fentanyl, thiopentone, halothane, and nitrous oxide. Relaxation was induced with atracurium 0.5 mg. kg-1 and maintained with supplements of 0.15 mg. kg-1. The ulnar nerve was stimulated with train-of-four (TOF) and double burst stimulation (DBS). Evoked MMG responses were recorded. Patients were randomized to spontaneous recovery (n = 20) or to assisted recovery by neostigmine (0.07 mg.kg-1) at varying intervals (6-50 min) from the last atracurium dose (n = 83).

RESULTS

The reversal time (time from administration of neostigmine to TOF ratio 0.7) was always < 13 min, when T1 (first twitch in TOF) was detectable or when D1 (first twitch in DBS) was > 5%. Total assisted recovery time (time from last supplemental atracurium dose to TOF ratio 0.7) increased with increasing T1 and D1 twitch heights (P < 0.05). The curve fitted to the scattergram with total assisted recovery time vs time from last atracurium supplement to neostigmine administration decreased to reach a minimum after which it increased to approach the line of identity. The minimum of the curve (total assisted recovery time 30.7 min) was reached when neostigmine was given 18.6 min after last atracurium supplement. At this time the T1 and D1 twitch height averaged 4 and 8% respectively. If prolongation of the minimum total recovery time of 2.5% is accepted, neostigmine can be given at T1 and D1 twitch height values of 0 to 8% and 4 to 15%, respectively.

CONCLUSION

The optimum time for neostigmine administration, taking both the reversal time and total recovery time into consideration, is when 0 < T1 < 8% or when 5 < D1 < 15%. Giving neostigmine at more profound degrees of blockade prolongs reversal time, while giving neostigmine later in the recovery phase prolongs total recovery time.

[Viper bites]

Two cases of bites by the common viper were reviewed. Emphasis was focused on proper medical monitoring in an intensive care unit for a minimum of one day. Observations should include ECG, Hb, leucocytes, electrolytes in both blood and urine, CPK, and coagulation factors. Surgical intervention, heparin and cryotherapy are not recommended. Proper treatment with immobilisation of the bitten extremity, tetanus antitoxin and volume therapy is recommended. In severe cases Zagreb Antitoxin should be used. Patients with cardio-pulmonary problems require special attention.

Comparison of tactile and mechanomyographical assessment of response to double burst and train-of-four stimulation during moderate and profound neuromuscular blockade

It is common clinical practice to estimate the degree of neuromuscular blockade by tactile evaluation of twitch responses. The aim of the present study was to evaluate the use of tactile responses of adductor pollicis to double-burst stimulation (DBS) and train-of-four (TOF) peripheral nerve stimulation for monitoring moderate and profound levels of neuromuscular blockade. The study comprised 44 women scheduled for gynaecological laparotomy and anaesthetised with midazolam, fentanyl, thiopentone, halothane, nitrous oxide and atracurium. The tactile responses of the adductor pollicis were compared with mechanomyographical measurements in the contra lateral arm during recovery from neuromuscular blockade. The observers (anaesthetic nurses) of the tactile responses were blinded with regard to the stimulation pattern and the mechanomyographical measurements. The time from injection of the initial dose of atracurium until tactile reappearance of the first twitch in DBS (D1), was 24.6 (0-39.8) min, median (range). This was more rapid than the time until tactile reappearance of the first twitch in TOF (T1) 32.8 (18.2-43.4) min (P < 0.05). The median time from tactile reappearance of D1 until T1 recovered to 15% of the control twitch height was longer than the median time from tactile reappearance of T1 (14.6 versus 10.5 min) (P < 0.05). One or two responses to DBS or TOF were often felt before any responses had been detected mechanomyographically in the contralateral arm. When three or four responses to TOF were felt, responses were always detected mechanomyographically. It is concluded that tactile evaluation of responses ot DBS stimulation can estimate deeper levels of blockade than tactile evaluation of responses to TOF.

[Gastric tonometry. Use in critically ill patients]

Gastric tonometry is a simple, minimally invasive method for measuring the oxygenation of the gastric mucosa. The present monitoring of patients in the ICU is by global measurements. A clinically usable method for monitoring at tissue level is presented. Securing the oxygenation of the gastrointestinal tract seems to be very important in the efforts to secure a sufficient global oxygenation. A review and evaluation of the literature concerning gastric tonometry in intensive care medicine is presented. History, method and potential errors are described. At the moment the numbers of studies being done on gastric tonometry are rapidly increasing.

Fatty acids and antioxidants in the Inuit diet. Their role in ischemic heart disease (IHD) and possible interactions with other dietary factors. A review

The recent literature on the role of fatty acids and antioxidants as protective factors in ischemic heart disease (IHD) has been reviewed. Serum cholesterol, especially LDL-cholesterol, is regarded as an index of risk for IHD. Epidemiological studies have connected a high dietary intake of n-3 fatty acids with a low occurrence of IHD. It is believed that this effect is brought about by a modification of the eicosanoid synthesis and a lowering of the cholesterol level. Intervention studies have not demonstrated that n-3 acids can lower the level whereas monounsaturated fatty acids (MUFAs) have been shown to have such an effect although they were previously believed to be neutral. The epidemiological observations probably reflect the combined effect of both n-3 polyunsaturated fatty acids (PUFAs) and MUFAs. Recently, oxidized LDL has been suggested to be involved in the earliest lesion of atherogenesis. This hypothesis suggest that the antioxidant balance is an important factor for IHD. As the traditional Greenlandic diet is rich in n-3 PUFAs, MUFAs and antioxidants (selenium), epidemiological studies in Greenland could shed important light on the role of individual dietary components and their interactions.

[Necrotizing fasciitis. A rapid fatal course of Streptococcus pyogenes, Lancefield group A serotype M1 (killer streptococci), infection]

The case history of necrotizing fasciitis in a previously healthy man aged 37 years is presented. The disease ran a rapidly fatal course. The only finding on bacterial culture was Streptococcus pyogenes, Lancefield group A, serotype M1, ("killer streptococci"). The therapeutic possibilities are briefly outlined and the importance of rapid surgical intervention is emphasized. It is concluded that this patient was actually beyond therapeutic aid less than 12 hours after admission. Necrotizing fasciitis caused by Streptococcus pyogenes, Lancefield group A, serotype M1, is comparable with meningococcal disease. It appears probable that the disease had developed in this patient as a sequel of streptococcal arthritis.

Localization of epsilon-lysyl-gamma-glutamyl cross-links in five human alpha 2-macroglobulin-proteinase complexes. Nature of the high molecular weight cross-linked products

Covalent binding of proteinases by human alpha 2-macroglobulin (alpha 2M) results primarily from the formation of stable epsilon-Lys-gamma-Glu isopeptide bonds. Cross-linking engages 12, 13, and 10 of the 14, 14, and 11 Lys residues in chymotrypsin, trypsin, and subtilisin, respectively, and reaction with the alpha-amino group of the C-chain of chymotrypsin and the B-chain of beta-trypsin is also seen. In contrast, cross-linking engages only 6 of the 11 Lys residues in thermolysin. In each of these proteinases, a few residues react to the greatest extent: Lys36, Lys79, Lys87, and Lys93 in chymotrypsin; Lys87, Lys109, Lys222, and Lys239 in trypsin; Lys12, Lys43, and Lys141 in subtilisin; and Lys210 and Lys219 in thermolysin. In elastase, 1 of the 3 Lys residues (Lys87) is tentatively identified as being cross-linked. Formation of unstable bonds judged to be mainly p-tyrosyl-gamma-glutamyl esters can also be significant for some proteinases. In each of the proteinases, several of the strongly reacting Lys residues are located relatively close to each other, presumably reflecting steric constraints within the alpha 2M-proteinase complexes as they form. Proteinases are covalently bound to alpha 2M to one or two of its COOH-terminal bait region-cleaved half-subunits. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern of the high molecular weight cross-linked species indicates that binding of a proteinase through two cross-links occurs not only within the 360-kDa disulfide-bridged alpha 2M dimer but also between the two dimers in the alpha 2M tetramer.