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Biomedical subjects

L Hermansen

Publications and source records attributed to L Hermansen.

At least 19 recordsLinked to original sources
PubMed2006

Occurrence of Cryptosporidium oocysts and Giardia cysts in sewage in Norway.

Samples of sewage influent from 40 sewage treatment works (STW) throughout Norway were examined for Cryptosporidium oocysts and Giardia duodenalis cysts. Both parasites were detected frequently (80% of STW were Cryptosporidium positive; 93% of STW were Giardia positive) and at maximum concentrations of > 20,000 parasites/liter. The data suggest giardiasis is more widespread, and/or occurs with greater infection intensity, than cryptosporidiosis in Norway. STW serving higher person equivalents were more likely to be positive and had higher parasite concentrations. Parasite concentrations were used to estimate the proportion of contributing populations that could be clinically infected. For Cryptosporidium, the highest estimates were up to 5 per 100,000 individuals for two populations in eastern Norway. For Giardia, the highest estimate was 40 infected per 100,000 persons (approximately five times the usual national annual average) contributing to an STW in western Norway. As this population experienced a large waterborne giardiasis outbreak 6 months after sampling, it can be speculated that regular challenge with Giardia may occur here. Most Giardia isolates in sewage influent were assemblage A, although some assemblage B isolates were detected. There was substantial heterogeneity, but most samples contained isolates similar to genotype A3. Removal efficiencies at two STW with secondary treatment processes were estimated to be approximately 50% for Cryptosporidium and > 80% for Giardia. An STW with minimal treatment had negligible removal of both parasites. Many STW in Norway have minimal treatment and discharge effluent into rivers and lakes, thus, risk of contamination of water courses by Cryptosporidium and Giardia is considerable.

Animals↗
PubMed2006

Application of genotyping during an extensive outbreak of waterborne giardiasis in Bergen, Norway, during autumn and winter 2004.

During the autumn and winter of 2004 and 2005, an extensive outbreak of waterborne giardiasis occurred in Bergen, Norway. Over 1,500 patients were diagnosed with giardiasis. Analysis of water from the implicated source revealed low numbers of Giardia cysts, but the initial contamination event probably occurred up to 10 weeks previously. While sewage leakage from a residential area is now considered to be the probable source of contamination, during the episode waste from one particular septic tank was thought to be a possible source. Genotyping of cysts from the septic tank demonstrated that they were assemblage A cysts, although the sequences were not identical to any previously published sequences. For the beta-giardin gene, the closest published subgenotype was subgenotype A3; for the gdh gene, the closest published subgenotype was subgenotype A2. Genotyping of cysts from 21 patient samples revealed that they were assemblage B cysts; thus, the septic tank was unlikely to be the contamination source. Sequencing of the beta-giardin and gdh genes from patient samples and a comparison of the sequences gave complex results. For the beta-giardin gene, three isolates had sequences identical to subgenotype B3 sequences. However, other isolates had between one and four single-nucleotide polymorphisms (SNPs). For the gdh gene, none of the sequences were identical to the sequence published for subgenotype B3, and the sequences had between one and three SNPs. One isolate, which was identical to subgenotype B3 at the beta-giardin gene, was more similar to subgenotype B2 at the gdh gene. Grouping the isolates on the basis of SNPs resulted in different groups for the two genes. The results are discussed in relation to giardiasis in Norway and to other Giardia genotyping studies.

Adult↗
PubMed2006

Cryptosporidium parvum infections in Bergen, Norway, during an extensive outbreak of waterborne giardiasis in autumn and winter 2004.

During a large waterborne giardiasis outbreak in Norway, many diarrheic patients were found to have Cryptosporidium infections. Gene sequencing identified these infections as Cryptosporidium parvum infections, although they were not identical. Whether these infections were due to a simultaneous outbreak of waterborne cryptosporidiosis or reflected background levels not normally detected is discussed.

Adolescent↗
PubMed2001

Early warning of faecal contamination of water: a dual mode, automated system for high- (< 1 hour) and low-levels (6-11 hours).

There is a recognised need for methods that permit rapid estimation of the sanitary quality of water e.g. during raw water monitoring and emergencies involving water treatment failure or main breaks in a distribution network. In this study, two models for predicting the level of faecal contamination of water were studied. The first format, based on measurement of beta-galactosidase activity by the automated Colifast analyser, detected faecal contamination of high levels, corresponding to > 15 thermotolerant coliforms (FC)/5 mL, in 1-3 h, in a format that allowed for semi-quantification of results. By setting up a cut-off level, the system could be used as an operational tool identifying random increases in faecal contamination during routine raw water monitoring. A second Presence-Absence format was dependent upon the growth of low levels of FC with subsequent detection in the Colifast analyser. 95% of water samples containing 1-15 FC/sample volume showed positive detection after 11 h.

Automation↗
PubMed1999

[Dietary guidelines on obesity at Danish pharmacies. Results of a 12-week course with a 1-year follow-up. Research Group on Human Nutrition, Frederiksberg].

The increasing prevalence of obesity has created a need for alternative counselling sites. This retrospective study evaluates the results of a 12 week slimming course for obese subjects held at Danish pharmacies at one year follow-up. Two hundred and sixty-nine obese (BMI > 25 kg/m2, 32 +/- 4.5 [mean +/- SD]) paid 550 Dkr each for a 12 weeks slimming course held at 19 Danish pharmacies with groups of 8-20 subjects each. The age was between 18 to 81 years, 259 were females. The course included eight sessions of 1 1/2 hour education in nutrition and physiology aiming for a dietary change toward a low-fat, high carbohydrate diet. Self-reported body weight was assessed on at the pharmacy scale before and after the course and again after three, six and 12 months follow-up. One hundred and ninety-one or 71% of subjects completed the 12 week slimming programme. The average weight loss was 5.3 and 6.2 kg among females and males, respectively. The weight loss maintenance was assessed at one year follow-up in 122 (45%) of the subjects who entered the course and was 4.0 and 6.7 kg in 118 females and four males, respectively. At one year follow-up 40 subjects (20%) of the subjects who completed the course had maintained a weight loss > 5 kg. In conclusion, the initial weight loss, and maintenance and drop-out rate are comparable with results from general practitioners and hospital out-patient clinics, but the costs are substantially lower.

Adolescent↗
PubMed1984

Muscle glycogen depletion patterns in type I and subgroups of type II fibres during prolonged severe exercise in man.

Glycogen depletion of muscle fibre types I, II A, II AB and II B was studied using a histochemical method to quantify glycogen content in individual fibres. The reliability was examined in 29 muscle biopsies, in which total glycogen content was compared to average periodic acid Schiff (PAS) stain intensity in sections from the same samples. Over a wide range of glycogen content (1-252 mmole glucosyl units . kg-1 wet weight) a linear relationship (r = 0.93) was found between the two methods for quantification of muscle glycogen. Glycogen depletion patterns in type I, II A, II AB and II B fibres were studied in 5 subjects during exhaustive bicycle exercise at 75% of VO2 max. At rest before exercise glycogen content was 16% higher in type II subgroups than in type I (p less than 0.05). From start of exercise the same glycogen depletion rate was observed in type I and II A. Glycogen content of Type II AB and II B was unchanged during the first part of exercise. Later a decrease was observed, first in type II AB and finally in II B, suggesting a decrease in threshold force of these fibre types. The results indicate physiological differences between the 3 subgroups of type II fibres in man, whereas at the present exercise intensity type I and II A fibres were recruited simultaneously from start.

Adult↗
PubMed1984

Intramuscular fluid pressure during isometric contraction of human skeletal muscle.

Intramuscular fluid pressures were recorded in the vastus medialis of seven healthy male volunteers. Pressures were measured simultaneously at three different sites in the muscle by a catheter-tip transducer with extremely low volume-displacement characteristics and by two extracorporeal transducers connected to slit catheters. All three recording systems gave qualitatively similar results provided the catheters had inner diameters exceeding 0.53 mm and allowed measurement of pressures lasting as short as 1 s. Wick catheters yielded slower responses than slit catheters. At any position intramuscular fluid pressure increased linearly with force up to maximal voluntary contraction (MVC). However, slopes of these curves varied greatly mainly because the pressure was also a linear function of the distance from the fascia. The highest recorded pressure was 570 Torr. At prolonged submaximal contractions intramuscular fluid pressure oscillated independent of contraction force. The linearity of both the pressure-force relationship and the pressure-depth relationship is compatible with a simple model based on the law of Laplace because the muscle fibers are curved during contraction in this muscle. It is hypothesized that blood flow is first compromised deep in the muscle where pressure is highest and in general at lower stress or tension in short bulging muscles with great curvature of the fibers compared with long slender ones.

Adolescent↗
PubMed1984

Influence of exercise on the fiber composition of skeletal muscle.

Biopsy samples from the vastus lateralis muscle (VLM) of man were examined for fiber composition at rest and at selected intervals during prolonged exercise ranging in intensity from 40% to 75% of the total body maximal oxygen uptake (VO2max) and one-min bouts of exercise at 150% VO2max. Because of the heterogeneity of fibers in human VLM, studies were also completed where the effect of exercise on the fiber composition of the rat soleus muscle (SM) was examined. In some animals the SM from one hindlimb was removed 9 days prior to their being exercised after which the remaining SM was removed. Exercise reduced muscle glycogen in all experiments. In the studies with man, blood lactate exceeded 17 mmoles/l after the heavy exercise but was largely unchanged by endurance exercise. Colonic temperature of the exercised rats exceeded 40 degrees C. In studies where fibers were identified only as type I and type II, type II fibers in the VLM of all samples (16) taken at rest averaged 61.2 +/- 12.5% as compared to 59.0 +/- 12.0% after exercise (54 biopsy samples). In a second series of studies with man where the subtypes of type II fibers were identified, there were also no differences in fiber composition of the VLM after varying periods of exercise. Glycogen content and percent fiber composition were the same in right and left SM obtained from rested rats. Exercise (30 to 40 min) did not alter the fiber composition of the rat SM. These data demonstrate that the histochemically demonstratable myofibrillar actomyosin ATPase of skeletal muscle is not altered by a single exercise bout.

Adenosine Triphosphatases↗
PubMed1982

Metabolic acidosis and changes in water and electrolyte balance after maximal exercise.

The purpose of this investigation was to study lactate production and the consequent changes in acid-base status, and in water and electrolyte balance, in response to 1 min of maximal exercise in sprint- and endurance-trained subjects. So far, the results from only two subjects (one sprinter and one marathon runner) have been analysed. The rate of lactate production was higher in the sprinter than in the marathon runner, as shown by peak blood lactate concentrations of 20.8 and 13.3 mM for the two subjects, respectively. Arterial blood pH fell from 7.43 to 7.14 in the sprinter and from 7.44 to 7.23 for the marathon runner. The metabolic acidosis was partly compensated for by a lowering of arterial CO2 tension by 0.0775 kPa per 1 mM drop in base excess. In each subject large changes in water and electrolyte balance occurred. Haematocrit increased dramatically in both subjects, and the calculated decrease in plasma volume was 20% for the marathon runner and 30% for the sprinter. In each subject sodium was removed from the circulation in amounts sufficient to keep the plasma sodium concentration constant. Plasma potassium concentration was unrelated to the state of acidosis, being 2.5 mM above the resting concentration immediately after maximal exercise, and dropping by 3 mM in the subsequent 2-3 min of recovery during prevailing acidosis. The degree of lactic acidosis was large in both subjects, although more severe in the sprinter than in the endurance runner. However, buffer capacity and compensatory mechanisms were largely similar in both subjects.

Acidosis↗
PubMed1981

Effect of metabolic changes on force generation in skeletal muscle during maximal exercise.

During vigorous, strong contractions there is a rapid decline in the mechanical output or tension development in skeletal muscle. Several studies have indicated that this rapid decline in force development (often referred to as fatigue), is caused by metabolic changes in the muscles. During brief intense exercise there is a rapid breakdown of phosphocreatine and glycogen and a concomitant increase in the lactate and hydrogen ion concentration. The muscle lactate concentration is increased from about 1-2 mmol kg-1 wet weight at rest before exercise to approximately 25-30 mmol kg-1 wet weight immediately after intensive brief exercise to exhaustion. The muscle pH (i.e. the pH of muscle homogenates) falls from about 7.0 at rest to approximately 6.4 at exhaustion. The changes in the concentrations of ATP, ADP, and AMP are small. It is suggested that the changes in intracellular pH might affect the force generation of skeletal muscle by two different mechanisms: (1) The fall in intracellular pH reduces the activity of key enzymes in glycolysis, thus reducing the rate of ATP resynthesis, and (2) the increased hydrogen ion concentration has a direct effect on the contractile processes, thus reducing the rate of ATP utilization. It is suggested that the increased hydrogen ion concentration might be the common regulator for the maximal rate at which ATP is being utilized and the maximal rate at which it is being resynthesized.

Acidosis↗
PubMed1978

Muscle glycogen concentration during recovery after prolonged severe exercise in fasting subjects.

The influence of 12 h of fasting after prolonged severe exercise on the muscle glycogen concentration was studed in 5 normal subjects. The subjects exercised in the post absorptive state at 70% of max. Vo2 till exhaustion, then rested for 12 h. No food was allowed during recovery. Blood samples and muscle biopsies were obtained before exercise, immediately after the cessation of exercise, and after 2, 4, 6, 9 and 12 h of recovery. Muscle glycogen content decreased from 70.4 +/- 3.0 to 21.6 +/- 3.9 mmol glucosyl units/kg w.w. in response to exercise. After 4 h of recovery muscle glycogen had increased to 28.8 +/- 3.6 mmol glucosyl units/kg (P less than 0.025). During the next 8 h of recovery no further increase in glycogen concentration was observed. Mean plasma glucose concentration was observed. Mean plasma glucose concentration decreased from 5.25 +/- 0.16 to 4.37 +/- 0.18 mmol/l during exercise (P less than 0.001). No change in the plasma glucose level was observed during recovery. Immunoreactive insulin (IRI) concentration decreased from 15.9 +/- 1.0 to 10.2 +/- 0.5 micromicron/ml (P less than 0.001) during exercise, and remained at this level during recovery. It is concluded that some muscle glycogen repletion may occur after prolonged, severe exercise even under fasting conditions. It is suggested that this may proceed through an increased hepatic gluconeogenesis.

Adult↗