Biomedical subjects

J Hertel

Publications and source records attributed to J Hertel.

At least 19 recordsLinked to original sources

PubMed2006

Do voluntary strength, proprioception, range of motion, or postural sway predict occurrence of lateral ankle sprain?

Prevention of ankle sprain, the most common sporting injury, is only possible once risk factors have been identified. Voluntary strength, proprioception, postural sway, and range of motion are possible risk factors. A systematic review was carried out to investigate these possibilities. Eligible studies were those with longitudinal design investigating ankle sprain in subjects aged > or = 15 years. The studies had to have measured range of motion, voluntary strength, proprioception, or postural sway before monitoring incidence of lateral ankle sprain. Dorsiflexion range strongly predicted risk of ankle sprain. Postural sway and possibly proprioception were also predictors. Therefore the preliminary evidence suggests that people with reduced ankle dorsiflexion range may be at increased risk of ankle sprain.

Ankle Injuries↗

PubMed2004

Heredity of specific host-finding behaviour in Schistosoma mansoni miracidia.

Two strains of Schistosoma mansoni were used to investigate the hereditary basis of species-specific host recognition by analysing behavioural responses of miracidia to snail-conditioned water. An Egyptian strain of S. mansoni, capable of distinguishing its host snail Biomphalaria alexandrina from other snails was cycled repeatedly through Biomphalaria glabrata, the intermediate host of a Brazilian strain known to respond even to non-susceptible snails with high intensity. After 5 cycles in the non-natural host, miracidia of the Egyptian strain still retained their preference for the original host snail. In a second experiment, host-finding behaviour of hybrids between these two parasite strains was studied. In the F1 generation, hybrids of both parental combinations showed the same low degree of specificity as the pure-bred Brazilian strain. Approximately one quarter of F2 hybrids proved to be as discriminatory as the Egyptian strain, confirming dominant Mendelian inheritance of non-specificity in schistosome miracidial host-finding behaviour. Moreover, hybrids seem to have lost the ability to develop in B. alexandrina, possibly suggesting a link between host recognition and host compatibility. The heredity of this behavioural trait is of evolutionary and epidemiological significance, since a shift to low host-finding specificity might have been a prerequisite for S. mansoni to acquire new host snails after being introduced to South America by the slave trade.

Animals↗

PubMed2004

Effect of an acute bout of soccer heading on postural control and self-reported concussion symptoms.

Our purpose was to determine if an acute bout of heading soccer balls adversely affected postural control and self-reported symptoms of cerebral concussion. Thirty-one college-aged soccer players were randomly placed into either a kicking group or a heading group. Subjects either kicked or headed 18 soccer balls over the course of 40 minutes. Subjects had their postural control assessed while standing on a force plate and completed a concussion symptoms checklist on three separate occasions: prior to, immediately following, and 24 hours after kicking or heading. There were no significant differences between the heading and kicking groups on the postural control measures prior to, immediately following, and 24 hours after kicking/heading. The heading group did, however, report significantly more concussion symptoms than the kicking group immediately after heading, but not 24 hours after heading. The number of previous concussions sustained by subjects did not influence the effects of heading. An acute bout of soccer heading appears to cause an increase in self-reported symptoms of cerebral concussion lasting less than 24 hours but no quantifiable deficits in postural control. Further research is needed to investigate the cumulative effects of soccer heading on postural control and other objective measures of brain function.

Adult↗

PubMed2004

Perinatal risk factors of adverse outcome in very preterm children: a role of initial treatment of respiratory insufficiency?

AIM: To investigate risk factors of adverse outcome in a cohort of very preterm children treated mainly with nasal continuous positive airway pressure (CPAP) during the neonatal course. METHODS: In Denmark, preterm children are treated with nasal CPAP as a first approach to respiratory support. A national prospective study of all infants with a birthweight below 1000 g or a gestational age below 28 wk born in 1994-1995 was initiated to evaluate this approach. Of the 269 surviving children 164 (61%) were not treated with mechanical ventilation in the neonatal period. A follow-up of the children at 5 y of age was conducted. Data from the neonatal period and the 5-y follow-up were analysed. RESULTS: In multivariate analyses including 250 children, a severely abnormal neonatal brain ultrasound scan was predictive of cerebral palsy (OR = 19.9, CI 95%: 6.1-64.8) and intellectual disability (OR = 6.2, CI 95%: 2.3-16.5). A high Clinical Risk Index for Babies (CRIB) score (OR = 2.4, CI 95%: 1.1-5.5) and chronic lung disease (OR = 2.8, CI 95%: 1.2-6.9) were predictive of intellectual disability. In univariate analyses mechanical ventilation was associated with cerebral palsy (OR=4.3, CI 95%: 1.7-10.8) and intellectual disability (OR = 2.2, CI 95%: 1.2-4.2), but the associations became insignificant in multivariate analyses including chronic lung disease and a severely abnormal ultrasound scan. CONCLUSION: The associations between neonatal risk factors and adverse outcome in our cohort were very similar to those found in other cohorts with another initial treatment of respiratory insufficiency. We found no significant adverse effects of mechanical ventilation beyond what could be explained by associations with chronic lung disease and IVH 3-4/PVL.

Cerebral Palsy↗

PubMed2004

Clinical features and epidemiology of septicaemia and meningitis in neonates due to Streptococcus agalactiae in Copenhagen County, Denmark: a 10 year survey from 1992 to 2001.

AIM: To elucidate the clinical and biochemical features, and to estimate the incidence and outcome of invasive culture-verified group B streptococcal (GBS) septicaemia/meningitis in neonates in Denmark. METHODS: Clinical microbiology laboratory records in patients 0-3 mo of age were searched for culture-verified GBS during 1992-2001 in Copenhagen County. Clinical records at the neonatal intensive care unit were reviewed retrospectively. Selected clinical and biochemical parameters were evaluated. RESULTS: 61 neonates had culture-verified GBS septicaemia/meningitis. The mean annual incidence was 0.76 cases per 1000 livebirths (range 0.0-1.91). A significant decrease in incidence was observed in the latest 3 y. The male:female ratio was 1.3:1. Eighty percent of the neonates had early-onset GBS within 24 h, 57% with symptoms at birth. Predominant initial symptoms were respiratory (72%), cardiovascular (69%) and neurological (63%). Only 4% developed GBS by day 7-90. Seventy-five percent had maternal or neonatal risk factors for early-onset GBS disease; 21% had clinical asphyxia, 37% of the mothers had premature rupture of membranes and 31% of the mothers were febrile. Initial C-reactive protein (CRP) was low, but increased significantly after more than 12 h duration of symptoms in 82% of patients. Leucopenia was an important initial haematological marker. CONCLUSION: The incidence of early-onset GBS has decreased significantly in Denmark, probably because of preventive measures in pregnancy and during birth. Respiratory symptoms are early signs of early-onset GBS. Initial leucopenia and a late (12-48 h) increase in CRP are valuable markers for invasive GBS.

C-Reactive Protein↗

PubMed2004

Combining isometric knee extension exercises with hip adduction or abduction does not increase quadriceps EMG activity.

OBJECTIVE: To determine if the combined isometric contractions of knee extension/hip adduction and knee extension/hip abduction will elicit a different quadriceps and gluteus medius electromyographic (EMG) pattern as compared to isometric contraction of a uniplanar knee extension exercise. METHODS: Eight healthy young adult volunteers without history of knee or quadriceps injury participated. Surface EMG data were collected from the vastus medialis oblique (VMO), vastus lateralis (VL), and gluteus medius (Gmed) muscles of the dominant leg of each subject during three single leg, weight bearing, isometric exercises (uniplanar knee extension, knee extension/hip adduction, knee extension/hip abduction). All exercises were performed at a position of 60 degrees knee flexion. Three trials lasting 5 s each were performed for each of the three exercises. EMG data from each muscle were integrated and the maximum root mean square activity over a 0.5 s window for each trial was averaged. Analyses of variance were performed with exercise (straight extension, extension/adduction, extension/abduction) as the independent variable and VMO, VL, and Gmed activity and VMO:VL ratio as dependent variables. RESULTS: A significant main effect for exercise was found for the VMO (p = 0.006) and VL (p = 0.02), but not the Gmed (p = 0.25) or the VMO:VL ratio (p = 0.13). For the VMO and VL, the uniplanar knee extension task produced significantly more EMG activity than the extension/adduction or extension/abduction tasks. CONCLUSIONS: Uniplanar knee extension exercises may be more appropriate than combining isometric knee extension exercises with hip adduction or abduction when eliciting maximal VMO and VL contractions.

Adult↗

PubMed2003

Static innominate asymmetry and leg length discrepancy in asymptomatic collegiate athletes.

The objectives of the study were to assess: (1) static innominate asymmetry in the sagittal plane, (2) leg length discrepancy (LLD), and (3) the relationship between static innominate rotation and LLD in asymptomatic collegiate athletes. The study was an observational study by design which took place in a University athletic training research laboratory. The participants were twenty-four male and 20 female asymptomatic intercollegiate athletes who volunteered to take part in the study. Static innominate asymmetry was assessed with a caliper/inclinometer tool and LLD was measured with a tape measure using standard clinical methods. Results showed that forty-two subjects (95%) demonstrated some degree of static innominate asymmetry. In 32 subjects (73%), the right innominate was more anteriorly rotated than the left. Nearly all subjects were determined to have unequal leg lengths with a majority, 30 subjects (68%), showing a slightly longer left leg. Weak correlations (r=0.33 - 0.44) were identified between static innominate asymmetry and LLD. In Conclusion static innominate asymmetry and LLD are common among asymptomatic collegiate athletes. This information provides clinicians with normative data of common clinical measures in a physically active population.

Adult↗

PubMed2003

Description of a tandem repeated DNA sequence of Echinostoma caproni and methods for its detection in snail and plankton samples.

Echinostome larval stages in the snail have a great potential as effective competitors for the control of schistosomes and adult worms can cause painful intestinal diseases in humans. Ecology and transmission of the larval stages of trematodes are poorly understood, especially because their identification in field-collected samples by microscopy is difficult. We cloned, sequenced and analysed a 192 bp tandem repreated DNA sequence of Echinostoma caproni (EcSau3A), an often discussed antagonist of Schistosoma mansoni in Biomphalaria snails. PCR primers against this sequence can detect less than 10 fg of E. caproni DNA, 2 miracidia in snails 1 day p.i., 1 metacercaria in 50 mg snail tissue and 1 cercaria in 50 mg plankton with high specificity. Methods described in this study can support the discovery of fundamental ecological principles on distribution, host specificity and epidemiology of E. caproni larvae under field conditions.

Animals↗

PubMed2003

Miracidia of an Egyptian strain of Schistosoma mansoni differentiate between sympatric snail species.

The host-finding behavior of miracidia of 2 strains of Schistosoma mansoni from Egypt and Brazil was studied by recording their responses to snail-conditioned water (SCW) from the Egyptian sympatric snails, Biomphalaria alexandrina, Physa acuta, Lymnaea cailliudi, and Balinus truncatus, as well as from Biomphalaria arabica and Biomphalaria glabrata. Miracidia of the Egyptian strain significantly preferred SCW from their compatible hosts B. alexandrina and B. arabica and showed no or a weak response to SCW from the other sympatric species, whereas miracidia of the Brazilian strain did not differentiate between SCW from different snail species.

Animals↗

PubMed2001

Effect of rearfoot orthotics on postural sway after lateral ankle sprain.

OBJECTIVE: To investigate the effects of different rearfoot orthotics on postural sway during unilateral stance after lateral ankle sprain. DESIGN: Repeated-measures 3-factor analysis of variance on postural sway length and velocity in the frontal and sagittal planes with factors being stance leg (injured, uninjured), session (within 3 d, 2 wk, 4 wk postinjury), and condition (6 orthotic conditions). SETTING: University biomechanics laboratory. PATIENTS: Fifteen collegiate athletes with acute, unilateral first- or second-degree lateral ankle sprain. INTERVENTIONS: Balance testing was performed under 6 conditions: (1) shoe only, (2) molded Aquaplast orthotic, (3) lateral heel wedge, (4) 7 degrees medially posted orthotic, (5) 4 degrees laterally posted orthotic, and (6) neutral orthotic. MAIN OUTCOME MEASURES: Postural sway length and postural sway velocity in the frontal and sagittal planes. RESULTS: Significant main effects were found for side and session, but not orthotic condition, for all 4 dependent variables. Postural sway length and velocity were greater on the injured limbs as compared with the uninjured limbs during the first 2 sessions but not during the third session. None of the orthotics significantly reduced postural sway compared with the shoe-only condition after lateral ankle sprain. CONCLUSIONS: Rearfoot orthotics, irrespective of design or posting, were ineffective at improving postural sway after lateral ankle sprain.

Adult↗

PubMed2001

Search for polyprenols in leaves of evergreen and deciduous Ericaceae plants.

Various species and cultivars of Ericaceae family were checked for the presence of long-chain polyprenols in their leaves. In the genus Rhododendron no polyprenols were found in the ever-green species, while they were present in the deciduous type. The polyprenols were of chain-length of 14-20 isoprene residues and they occurred in the form of acetic acid esters. The polyprenol accumulation is discussed with respect to senescence of leaves.

Chromatography, High Pressure Liquid↗

PubMed2000

Host-finding in Echinostoma caproni: miracidia and cercariae use different signals to identify the same snail species.

The snail host signals releasing host-finding responses in miracidia and cercariae of Echinostoma caproni were analysed by fractionation of snail-conditioned water (SCW). Cercariae responded non-specifically to organic and hydrophilic, low molecular weight components of SCW showing their typical turning response. Hydrolysis of peptides in SCW had no effect on cercarial responses. An artificial mixture of amino acids in concentrations determined from SCW as well as glycine alone in a concentration corresponding to the total concentration of amino acids in SCW showed nearly the same efficacy as SCW itself. Miracidia responded to a high molecular weight glycoprotein fraction, which could be isolated from SCW by ion-exchange and size-exclusion chromatography. In contrast to an Egyptian Schistosoma mansoni strain, the echinostome miracidia were not able to differentiate between different snail species. The results show for the first time that miracidia and cercariae of the same species may use different signals to identify the same snail host species. This indicates an independent evolution of host-finding mechanisms in the two parasite stages.

Animals↗

PubMed2000

Functional instability following lateral ankle sprain.

Lateral ankle sprain (LAS) is an extremely common athletic injury. Despite extensive clinical and basic science research, the recurrence rate remains high. Functional instability (FI) following LAS is hypothesised to predispose individuals to reinjury because of neuromuscular deficits which result following injury. This paper provides an overview of the potential causes of FI which may manifest themselves clinically. The theoretical explanations of FI are discussed, as are implications for assessment and treatment of FI following LAS. When LAS occurs, structural damage not only occurs to the ligamentous tissue, but also to the nervous and musculotendinous tissue around the ankle complex. While injury to the ligaments may result in laxity of the joints of the ankle complex, neuromuscular deficits are also likely to occur due to the injury to the nervous and musculotendinous tissue. These neuromuscular deficits may be manifested as impaired balance, reduced joint position sense, slower firing of the peroneal muscles to inversion perturbation of the ankle, slowed nerve conduction velocity, impaired cutaneous sensation, strength deficits and decreased dorsiflexion range of motion. Additionally, the abnormal formation of scar tissue after injury may lead to sinus tarsi syndrome or anterolateral impingement syndrome, which may also lead to FI of the ankle complex. Assessment of patients with LAS must address not only joint laxity and swelling, but should include examination for neuromuscular deficits as well. The treatment and rehabilitation goals must also address restoration of neuromuscular function, as well as restoration of mechanical stability to the injured joints.

Ankle Injuries↗

PubMed2000

How can hemodialysis-associated hypotension and dialysis-induced symptoms be explained and controlled--particularly in diabetic and arteriosclerotic patients?

Patients with diabetes and/or severe arteriosclerosis are often unable to tolerate volume removal during hemodialysis (HD) and develop hemodialysis-induced symptoms. These problems can be omitted by well-balanced correction of the acid/base status. We compared 20 high-risk patients which were either treated with standard HD (dialysate bicarbonate 33 mmol/l, treatment A) or treated with standard HD and additional administration of NaHCO3 (120-160 ml 8.4% NaHCO3 solution over the venous line during HD) to correct the metabolic acidosis to upper normal values (treatment B). The following parameters were compared: 1. Acid/base status; 2. EEG monitoring and clinical observation of dialysis-induced symptoms; 3. Invasive monitoring of circulation by Swan-Ganz thermodilution; 4. Ventilation, oxygen consumption and lactate production. Optimal correction of acid/base values resulted in symptom-free hemodialysis sessions with stable PaCO2 in the normal range, cardiovascular stability assessed by invasive monitoring, normal ventilation and higher oxygen consumption and decreased lactate production. Optimal correction of acid/base balance further led to the absence of EEG alterations and of dialysis-induced symptoms during treatment B as compared to treatment A. The baroreceptor response in these patients is usually disturbed due to sclerosis of the pressosensible vessels, especially the aortic arch and the pulmonary arteries impairing a compensatory increase of heart rate upon volume removal. However, chemoreceptors are able to increase sympathetic tone with preservation of blood pressure in this situation. In addition a decrease of PaO2 during volume removal can only be answered by an early increase of ventilation response due to stimulation of chemoreceptors provided that PaCO2 is maintained normal. Furthermore, normal cerebral blood flow also depends on a normal PaCO2. Based on these pathophysiological mechanisms the therapeutic strategy of additional bicarbonate administration to correct the acid/base status guarantees a stable normal PaCO2 and facilitates a symptom-free HD in high-risk patients.

Arteriosclerosis↗

PubMed2000

Single polyprenol and dolichol isolation by semipreparative high-performance liquid chromatography technique.

A new method of separation of single polyprenols (or dolichols) from a mixture of isoprenoid alcohols is described. Application of a high-performance liquid chromatography (HPLC) apparatus equipped with a semipreparative ODS column resulted in preparation of long-chain (dihydro)polyprenols of high purity (>95%). This approach substantially decreases the time scale of the conventional chromatographical preparative procedure. The method can be widely used in chemical and biochemical projects, where single polyprenols or dolichols are required.

Chromatography, High Pressure Liquid↗

PubMed1999

Feasibility of neonatal screening for toxoplasma infection in the absence of prenatal treatment. Danish Congenital Toxoplasmosis Study Group .

BACKGROUND: The best method for prevention and control of congenital toxoplasma infection is uncertain. Prenatal screening is done in Austria and France, but the effect of treatment during pregnancy is not well documented. The aim of our study was to find out the maternofetal transmission rate and outcome in infants born to mothers who were not treated during pregnancy. METHODS: We analysed 89873 eluates from phenylketonuria (PKU) cards from neonates and paired first-trimester serum samples from the mothers for specific IgG antibodies to Toxoplasma gondii. Children born to mothers who seroconverted during pregnancy were followed-up clinically and serologically to 12 months of age. In addition, 21144 PKU cards were analysed for toxoplasma-specific IgM antibodies during the last 12 months of the study. FINDINGS: In 24989 (27.8%) cases both the PKU eluate and the first-trimester samples were IgG positive, which indicates previous maternal infection. 139 of the 64884 seronegative women acquired toxoplasma infection during pregnancy and gave birth to 141 infants (two sets of twins). 27 of these children were diagnosed with congenital toxoplasma infection. The transmission rate was 19.4% (95% CI 13.2-27.0). Clinical signs and symptoms were found in four (15%) of the 27 children. The additional analysis for toxoplasma-specific IgM antibodies from the PKU card identified seven of nine children with congenital toxoplasma infection. The false-positive rate for the IgM test was 0.19 per 1000, and no false-negatives were found. INTERPRETATION: The risks of transmission of infection and of disease in the infant are low in an area with a low risk of toxoplasma infection. A neonatal screening programme based on detection of toxoplasma-specific IgM antibodies alone will identify between 70% and 80% of cases of congenital toxoplasmosis.

Adult↗

PubMed1999

Talocrural and subtalar joint instability after lateral ankle sprain.

PURPOSE: Recurrence of lateral ankle sprain (LAS) is common among recreational and competitive athletes. Talocrural (TC) joint laxity has traditionally been seen as the cause of mechanical instability after LAS. The purpose of this study was to examine the use of stress fluoroscopy and physical examination in the assessment of TC and subtalar (ST) instability in subjects with and without a history of LAS. METHODS: Twelve subjects with a history of unilateral LAS and eight healthy controls were examined by two blinded examiners. The first examiner performed physical examination on each ankle by using the anterior drawer (AD), talar tilt (TTPE), and medial subtalar glide (MSTG) tests. Laxity in each ankle was assessed on a 4-point scale. The second examiner performed stress fluoroscopy taking AP views with and without a manually applied supination stress to assess TC laxity and a sidelying modified Broden view with and without stress to assess ST laxity. Subjective examination of the images was used to determine excessive TC and ST laxity. RESULTS: Seventy-five percent of previously injured subjects demonstrated unilateral laxity differences of the TC joint using stress fluoroscopy. Of the nine with excessive talar tilt on fluoroscopy, 78% demonstrated excessive laxity with the AD and MSTG tests, and 67% demonstrated laxity with the TTPE test. Sixty-seven percent of those with TC laxity also demonstrated either excessive unilateral or bilateral laxity of the ST joint under stress fluoroscopy. CONCLUSIONS: These data suggest the existence of a subpopulation of patients with a history of LAS who demonstrate a pattern of combined TC and ST laxity.

Adult↗

PubMed1998

Contamination of poliovirus vaccines with simian virus 40 (1955-1963) and subsequent cancer rates.

CONTEXT: Poliovirus vaccine contaminated with live simian virus 40 (SV40), a macaque polyomavirus that is tumorigenic in rodents, was used extensively in the United States between 1955 and 1963. Simian virus 40 DNA has recently been detected in several rare human tumors, including ependymomas, osteosarcomas, and mesotheliomas. OBJECTIVE: To determine the risk of ependymoma, osteosarcoma, and mesothelioma among Americans who as children received SV40-contaminated poliovirus vaccine. DESIGN: Retrospective cohort study using data from the Surveillance, Epidemiology, and End Results program (1973-1993) and the Connecticut Tumor Registry (1950-1969), as well as national mortality statistics (1947-1973). SETTING: United States. PARTICIPANTS: Birth cohorts that were likely to have received SV40-contaminated poliovirus vaccine as infants, born 1956 through 1962 (60 811730 person-years of observation); as children, born 1947 through 1952 (46430953 person-years); or that were unexposed, born 1964 through 1969 (44959979 person-years). MAIN OUTCOME MEASURES: Relative risk (RR) of each cancer among exposed compared with unexposed birth cohorts. RESULTS: Age-specific cancer rates were generally low and were not significantly elevated in birth cohorts exposed to SV40-contaminated vaccine. Specifically, compared with the unexposed, the relative risk of ependymoma was not increased in the cohorts exposed as infants (RR, 1.06; 95% confidence interval [CI], 0.69-1.63), or as children (RR, 0.98; 95% CI, 0.57-1.69) nor did the exposed have an increased risk of all brain cancers. Osteosarcoma incidence also showed no relation to exposure as infants (RR, 0.87; 95% CI, 0.71-1.06) or children (RR, 0.85; 95% CI, 0.59-1.22). Last, mesotheliomas were not significantly associated with exposure, although the cohorts studied have not yet reached the age at which these tumors tend to occur. CONCLUSIONS: After more than 30 years of follow-up, exposure to SV40-contaminated poliovirus vaccine was not associated with significantly increased rates of ependymomas and other brain cancers, osteosarcomas, or mesotheliomas in the United States.

Adolescent↗