Congenital rubella: down but not out.
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Disease Outbreaks↗
Biomedical subjects
A Nardone
Publications and source records attributed to A Nardone.
Markers of oxidative status in plasma and erythrocytes of transition dairy cows during hot season.
The study was carried out to assess whether hot seasons affect the oxidative status of transition dairy cows. Twenty Holstein cows were utilized. Eleven of those cows gave birth in spring; the remaining nine cows gave birth in summer. Oxidative status was evaluated from 21 d before to 35 d after calving, determining oxidative markers in plasma [glutathione peroxidase activity, thiol groups, reactive oxygen metabolites, and thiobarbituric acid reactive substances (TBARS)] and in erythrocytes [glutathione peroxidase activity (GSH-Px-E), intracellular thiols (SH), superoxide dismutase activity (SOD) and TBARS]. The season did not modify plasma oxidative markers. In contrast, cows exposed to moderate heat stress (39.5 +/- 0.2 degrees C rectal temperatures) due to summer temperature-humidity index (73.2 +/- 2.5 mean daily THI), showed higher erythrocyte SOD, GSH-PxE, SH, and TBARS compared with spring cows, indicating a condition of oxidative stress in summer transition dairy cows. Some changes (the increase of SOD, for example), represent compensatory changes the cow is undergoing in response to increased oxidative stress. Under the conditions compared, the effect of heat stress on oxidative status in transition dairy cows by use of plasma markers does not give enough information to reach definitive conclusions. Erythrocytes are an appropriate and sensitive model to study the oxidative status of transition dairy cows exposed to hot environments.
Animals↗
[The capture-recapture applied to epidemiology: principles, limits and application].
By matching several sources of information coming from the same population, the capture-recapture method allows, if matches between sources can be identified, to estimate the number of cases not identified by any of the sources, the total number (N) of cases in the population and the sensitivity of each source. Used first in zoology and demography, this technique has been increasingly applied to epidemiology in the last two decades. However, six conditions need to be satisfied: all cases identified by each source are true cases; occurred during the time and the geographical area studied; the study population is closed; all matches are true matches; sources are independent and there is no heterogeneous catchability within sources. It is possible to assess and take into account dependence between sources when 3 or more sources are used, in particular by log linear modelling. However interactions of maximal order cannot be adjusted for. In case of a biased estimation because of the non respect of the conditions, it is recommended to apply a method of correction. The complete application of the methods is illustrated in the study of estimating the number of Salmonella infectious foodborne outbreak. As capture-recapture studies often use data collected for other purposes, this technique should be regarded as exploratory or be used to validate an estimate of a number of cases obtained by another method. It should not replace population sampling methods only because of its low cost. Otherwise it is a very informative approach to evaluate the sensitivity and representativeness of surveillance systems and registries.
Algorithms↗
A comparison of high-risk sexual behaviour and HIV testing amongst a bar-going sample of homosexual men in London and Edinburgh.
BACKGROUND: This study compared high-risk sexual and HIV testing behaviour amongst homosexual men recruited from gay bars in London and Edinburgh. METHODS: A cross-sectional survey monitoring high-risk sexual and HIV testing behaviour using a self-completed questionnaire was conducted in November and December 1996. RESULTS: Two thousand, three hundred and ninety-seven questionnaires were returned (1,366 recruited in London and 1,031 in Edinburgh), with a response rate of 77%. A larger proportion of men surveyed in London had had unprotected anal intercourse (UAI) with one or more male partners in the previous year (35%) than in Edinburgh (30%). Men recruited in Edinburgh were less likely to have had an HIV test (54%) than men in London (63%). In both surveys, 25% of men who reported UAI with partners of the same HIV status as themselves also reported never having had an HIV test. CONCLUSIONS: The observed dissimilarities in the HIV epidemic in the two cities may be accounted for by the differences in self-reported high-risk sexual and HIV testing behaviours between the two populations. A large proportion of men in both cities continue to engage in high-risk sexual behaviour suggesting continued transmission of HIV in these populations. Thus, there is a continued need for innovative and relevant health promotion amongst homosexual men in the UK.
AIDS Serodiagnosis↗
Stance control is not affected by paresis and reflex hyperexcitability: the case of spastic patients.
OBJECTIVES: Spastic patients were studied to understand whether stance unsteadiness is associated with changes in the control of voluntary force, muscle tone, or reflex excitability, rather than to abnormal posture connected to the motor deficit itself. METHODS: Twenty four normal subjects, 12 patients affected by amyotrophic lateral sclerosis (ALS), seven by spastic paraparesis, and 14 by hemiparesis were studied. All patients featured various degrees of spasticity and paresis but were free from clinically evident sensory deficits. Body sway during quiet upright stance was assessed through a stabilometric platform under both eyes open (EO) and eyes closed (EC) conditions. The sudden rotation of a supporting platform, in a toe up and toe down direction respectively, evoked short (SLR) and medium latency (MLR) reflex responses to stretch of the soleus or the tibialis anterior (TA) muscle. RESULTS: No relation was found between clinical findings (tone, muscle strength, tendon reflexes, plantar response, and duration of disease) and body sway. On average, all patient groups exhibited a forward shift of the centre of foot pressure (CFP) with respect to normal subjects; in addition, paraparetic and to a much larger extent hemiparetic patients showed a lateral shift of CFP. Body sway area was significantly increased only in the hemiparetic patients. No relation was found between position of the CFP and sway within any patient group. Soleus SLR was increased in all patients with respect to normal subjects. TA SLR was often seen in both patients with ALS and paraparetic patients, but only rarely in normal subjects and hemiparetic patients. However, no relation was found between amplitude of soleus or TA SLRs and stabilometric variables. The frequency and size of soleus MLR and TA MLR were decreased in all patients. These responses were decreased in size and not modulated by background EMG in the affected leg of hemiparetic patients, suggesting a disturbed control of spinal reflexes fed by spindle group II afferent fibres. CONCLUSIONS: It is proposed that body posture, paresis, or monosynaptic reflex hyperexcitability do not affect the control of equilibrium during quiet upright stance. In hemiparetic patients, the decreased amplitude of MLRs might be the main cause of the large postural instability. The results are congruent with the hypothesis of a role for group II afferent input in the reflex control of equilibrium.
Adult↗
Effects of subclinical pregnancy toxemia on immune responses in sheep.
OBJECTIVE: To determine the effects of moderate feed restriction, single or twin pregnancy, and subclinical pregnancy toxemia (PT) on immune responses of ewes. ANIMALS: 16 Sardinian ewes. PROCEDURE: Six weeks before lambing, ewes were assigned to 1 of 2 groups (n = 8/group) matched for number of fetuses, body condition score, and plasma glucose, non-esterified fatty acids (NEFA), and beta hydroxybutyrate (BHBA) concentrations, and feed intake was restricted for 1 of the groups. Cell-mediated immunity was evaluated in vivo and in vitro. Humoral immunity was evaluated in vivo by determining production of IgG antibodies against keyhole limpet hemocyanin (KLH). RESULTS: Four ewes developed subclinical PT (plasma BHBA concentration > 0.86 mmol/L without any clinical signs of disease). Whether feed was restricted and type of pregnancy (single vs twin) did not have any significant effects on cell-mediated and humoral immune responses. Ewes with subclinical PT had significantly lower in vitro proliferation of phytohemagglutinin-stimulated peripheral blood mononuclear cells and significantly lower values for KLH-specific IgG than did healthy ewes. Plasma BHBA and NEFA concentrations were negatively correlated with in vitro proliferation of peripheral blood mononuclear cells; plasma NEFA concentration was negatively correlated with values for KLH-specific IgG. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that subclinical PT may be associated with impairments in cell-mediated and humoral immune responses in sheep.
3-Hydroxybutyric Acid↗
Increase in high risk sexual behaviour among homosexual men, London 1996-8: cross sectional, questionnaire study.
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Adolescent↗
Loss of large-diameter spindle afferent fibres is not detrimental to the control of body sway during upright stance: evidence from neuropathy.
Fifteen patients with Charcot-Marie-Tooth type 1A (CMT1A) disease and 46 normal controls were studied. In the patients, leg muscle strength, touch-pressure, vibration and joint position sense were reduced; lower limb tendon reflexes were absent in 12 or markedly decreased. Motor and sensory conduction velocity (CV) of leg nerves was either reduced or not measurable. The Neurological Disability Score and the Neuropathy Score were obtained from clinical and electrophysiological examination, respectively. Tilt of a supporting platform elicited short- (SLR) and medium-latency (MLR) responses to stretch in the foot muscle flexor digitorum brevis (FDB) in controls. In the patients, the former response was absent and the latter delayed. These findings are in keeping with the known loss of large-diameter myelinated fibres, with relative sparing of the smaller fibres. The MLR delay was fully accounted for by the slowed CV of the motor fibres. The MLR afferent time was similar to that in normal subjects. Body sway area (SA) during quiet stance was recorded with eyes open or closed, and with feet apart or together. Under all postural and visual conditions, SA was within normal range in the less severely affected patients, but was moderately increased in the patients with a more severe neuropathy score. Across all patients, no correlation was found between SA and muscle force, motor CV, touch pressure, vibration and joint position sense, considered either separately or as an aggregate. We suggest that: (1) functional integrity of the largest afferent fibres is not necessary for appropriate equilibrium control during quiet stance and (2) any unsteadiness is related to additional functional alterations in smaller fibres, most likely group II spindle afferent fibres.
Adolescent↗
Postural coordination in elderly subjects standing on a periodically moving platform.
OBJECTIVE: To test body segment coordination during dynamic equilibrium on a moving platform, and assess age-related differences in the performance. DESIGN: Subjects had infrared light-emitting diode (LED) markers fixed on their temporomandibularjoint, greater trochanter, and lateral malleolus. Subjects stood upright on a sinusoidally translating platform with both feet, either with eyes open (EO) or eyes closed (EC). The platform was displaced horizontally in an anteroposterior direction at frequencies of 0.2 or 0.6Hz. Each trial, for either visual condition, was repeated twice, lasted 30 seconds, with 30-second intervals, for up to 1 hour. PARTICIPANTS: Fifty-three healthy subjects, aged 17 to 89 years. MAIN OUTCOME MEASURES: Kinematics of head and hip were analyzed by measuring periodic shift of LED markers using an optoelectronic device. Standard deviation on traces of the markers were taken as a comprehensive index of segment placement. Cross-correlation between marker traces was determined to obtain measures of degrees of coupling between body segments. RESULTS: At the low translation frequency (0.2Hz), with EO, subjects behaved like a noninverted pendulum, whereby the head tended to be stabilized more than the hip, and the legs taking up most of the imposed displacement. Aging was associated with greater head stabilization, and a looser coupling between head and hip. With EC, the body attitude changed to an inverted pendulum, whereby the head overshot the platform displacement. Aging was associated with reduced head stabilization, and a stronger coupling between head and hip. When the frequency of the platform translation increased to 0.6Hz, with EC, the general picture was similar to the above, but in older subjects vision was no longer able to counteract the imposed head displacement. At this frequency, with both EO and EC, there was a poor coupling between body segments across all ages. CONCLUSIONS: Periodic shift of the support base may be a valid protocol to test the ability to control balance in the elderly, and may be a useful tool to assess age-related changes of the sensorimotor mechanisms underlying dynamic equilibrium.
Adolescent↗
Standing on a continuously moving platform: is body inertia counteracted or exploited?
We describe the characteristics of displacement of the head and hip in normal young subjects standing on a moving platform undergoing continuous sinusoidal horizontal translation in the antero-posterior direction, at frequencies ranging from 0.1-1 Hz. The head, hip and malleolus were marked by light-emitting diodes (LEDs), and the displacement of each LED was quantified by (1) the measure of the shift during each cycle of translation, (2) the standard deviation (SD) of the path travelled during the whole trial, (3) the power spectrum (PS) of the signal and (4) the cross-correlation (CC) between pairs of LED signals. At each frequency of translation, with eyes open (EO), the displacement of head was smaller than that of hip, and the displacement of hip was smaller than that of malleolus. With eyes closed (EC), this order was reversed. The peak value of the CC functions of the pairs malleolus/head, malleolus/hip and hip/head decreased by passing from low to high frequency of translation, under both visual conditions, and decreased more for the pair malleolus/head than malleolus/hip. The lags between body segment displacements ranged between 30 ms and 150 ms, on average, the former segment of each pair preceding the latter. The fast Fourier transformation of hip and head displacement showed a power spectrum peak at the frequency imposed by the platform translation. The peak was larger with EC than EO. With EC, another peak appeared at 0.2 Hz, possibly corresponding to the respiratory frequency. We conclude that, when vision was allowed, subjects behaved as a non-rigid, noninverted pendulum, and stabilised head in space. When vision was denied, head oscillated more than the platform, especially at low translation frequencies. Therefore, the strategy of balance control shifted from a pendulum to an inverted-pendulum behaviour, passing from active head-and-trunk control to maximal body compliance to the perturbation.
Adult↗
Group II spindle afferent fibers in humans: their possible role in the reflex control of stance.
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Afferent Pathways↗
Developing surveillance for HIV transmission and risk behaviours among high-risk groups in a central London health district.
BACKGROUND: Our aim was to describe surveillance data on HIV transmission and risk behaviours in Camden and Islington, an inner London health district (population 360 000). This information is required to assess the effectiveness of HIV-AIDS prevention. METHODS: We focused on two groups in the local population most severely affected by the HIV epidemic: homosexual and bisexual men, and injecting drug users. Data were drawn from routine and survey data, national and local sources, and a special local survey. RESULTS: There were estimated to be 9250 homosexual men, with an estimated prevalence of 7.7 per cent (confidence interval (CI) 5.9-11.0) diagnosed with HIV infection resident within the health district, and 9900 injecting drug users, with an estimated prevalence of 0.8 per cent (CI 0.6-1.1), diagnosed with HIV infection. New HIV infections diagnosed amongst homosexual men having a named test in HIV testing services averaged 281 and was unchanged between 1992 and 1996. However, unlinked anonymous seroprevalence surveys showed a decline in HIV prevalence for both homosexual men attending a genito-urinary medicine clinic and for injecting drug users attending services. Local surveys indicated that, in the preceeding year, one in three homosexual men had had unprotected anal intercourse with a man, and 13 per cent of intravenous drug users had shared equipment. There appeared to be no change in these levels over the years studied. CONCLUSION: Population-based information on HIV is available at local level in England. It can be used for surveillance of HIV transmission and behaviour in high-risk groups, especially homosexual and bisexual men and intravenous drug users. Resources for HIV prevention are provided to all NHS districts, and surveillance is a cost-effective measure of the outcome of HIV prevention.
Adolescent↗
Subjective perception of body sway.
OBJECTIVES AND METHOD: The relation between body sway recorded through a stabilometric platform and the subjective report of steadiness was studied in 20 young and 20 elderly subjects and 20 neuropathic and 20 parkinsonian patients standing upright. The trials were performed under two stances (feet apart, feet together) and two visual conditions (eyes open, eyes closed). At the end of each trial, subjects scored their performance on a scale from 10 (complete steadiness) to 0 (fall). RESULTS: In all subjects, independently of the stance conditions, the larger the body sway the smaller the reported score. The function best fitting this relation was linear when sway was expressed on a logarithmic scale. The scoring reproducibility proved high both within and across subjects. Despite the different body sways and scores recorded under the different visual and postural conditions (eyes closed>eyes open, feet together>feet apart) in all groups of subjects and patients, the slopes of the relations between sway and score were broadly superimposable. In the normal subjects, the scores were slightly higher during eyes open than eyes closed trials for corresponding body sways. This was interpreted as a sign of perception of greater stability when vision was allowed. Parkinsonian patients swayed to a similar extent as normal subjects, and their scores were accordingly similar, both with eyes open and eyes closed. Neuropathic patients swayed to a larger extent than normal subjects, and their scores were matched appropriately. Although the slope of their relation with eyes closed was not different from that of normal subjects, with eyes open it was steeper and similar to that with eyes closed, suggesting that these patients did not feel more stable when they could take advantage of vision. CONCLUSIONS: The subjective evaluation of body sway, irrespective of stance condition, age, neuropathy, and basal ganglia disease, reflects the actual sway, and is inversely proportional to the logarithm of the sway value. The remarkable similarity of the relation between score and sway across the various groups of subjects with eyes closed indicates a common mode of sway evaluation, possibly based on integration of several sensory inputs. All groups except neuropathic patients seem to take advantage of the redundancy of the inputs. Basal ganglia integrity does not seem to have a role in the evaluation of sway.
Adult↗
Influence of short- and long-term exposure to a hot environment on rumen passage rate and diet digestibility by Friesian heifers.
Effects of short- and long-term exposure to a hot environment on diet digestibility and rumen passage rate were studied in four, 10-mo-old Friesian heifers housed in a climatic chamber. The trial lasted 65 d. Twenty-five days were spent under thermal comfort (temperature-humidity index = 64), and 40 d were spent under hot conditions (temperature-humidity index = 84). Three digestibility and rumen passage rate trials were performed during the 65 d. Chromium oxide was used as an external marker. The first digestibility and rumen passage rate trial (trial 1) was performed under thermal comfort; trials 2 and 3 were performed under hot conditions. Exposure to the hot environment reduced dry matter intake and increased water intake and rectal temperature compared with those during the thermal comfort period. Digestibility coefficients for dry matter, organic matter, neutral detergent fiber, and acid detergent fiber were higher in trial 2 than in trials 1 and 3. No statistical differences were found between trials 1 and 3 for these variables. Rumen passage rate was more rapid in trial 1 than in trials 2 and 3. No difference was observed between trials 2 and 3. These results indicated that exposure to a hot environment can affect digestibility in a time-dependent fashion, suggesting an adaptation of the digestive tract to hot environments.
Animals↗
"Try this HIV test"--an evaluation of a mass media campaign targeting homosexual men.
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AIDS Serodiagnosis↗
Medium-latency response to muscle stretch in human lower limb: estimation of conduction velocity of group II fibres and central delay.
In standing subjects, ankle dorsiflexion evoked short-latency responses (SLRs) at 41 and 57 ms, on the average, in soleus (Sol) and flexor digitorum brevis (FDB), respectively. Medium-latency responses (MLRs) occurred at 70 and 95 ms. The time between the MLRs was 25 ms and between the SLRs was 16 ms. The difference between these two values represents the extra-time to conduct the FDB volley for MLR from distal to proximal muscle, in excess to that for SLR. The velocity of the afferents mediating the FDB MLR (21.4 m/s on average) was estimated by dividing the distance between the two muscles by the sum of the above extra-time and the conduction time of Ia fibres along the same distance. The central delay of FDB MLR (6.7 ms on average) was obtained by dividing the distance between FDB and spinal cord by the sum of afferent and efferent MLR conduction times. The central delay of FDB SLR (1.4 ms) was analogously obtained. These findings give an estimation of the conduction velocity of the group II afferent fibres in humans and support the hypothesis that the FDB MLR is relayed through a spinal oligosynaptic pathway.
Adult↗
Time course of stabilometric changes after a strenuous treadmill exercise.
OBJECTIVE: To detect the effect of a strenuous exercise on equilibrium and to quantify its time course. PARTICIPANTS AND METHODS: Body sway area, sway path, and center of foot pressure were recorded in eight young able-bodied subjects, standing quietly with feet together, with eyes open (EO) and eyes closed (EC), on a dynamometric platform, before and after treadmill walking for 25min, during which subjects approached the maximum heart rate. RESULTS: A significant increase in body sway was observed after exercise. It was present under both visual conditions and affected both sway area and sway path. Sway increased most in the initial few minutes (sway area EO=800.7mm2 [p < .005], EC=1,779.5mm2 [not significant]; sway path EO=545mm [p < .0001], EC=811.8mm [p < .05]) with respect to preexercise values (sway area EO=449.4mm2, EC=1,316.2mm2; sway path EO=369.5 mm, EC=652.5mm) and was followed by a plateau (sway area EO=609.9mm2, EC=1,567.9mm2; sway path EO=431.2mm, EC=710.9mm). Full recovery to basal values occurred within about 15min after the end of the exercise. CONCLUSIONS: Body sway is affected by prolonged fatiguing exercise, such as strenuous walking. This effect is of moderate extent and vanishes within a few minutes.
Adult↗
Active surveillance of sexual behaviour among homosexual men in London.
The objective of this study was to establish a surveillance programme to monitor high risk sexual behaviour among homosexual and bisexual men socializing and/or using health care services in London. Between November 1996 and January 1997 a brief, self-completed questionnaire was distributed in various commercial venues (bars, clubs, and saunas) and genitourinary medicine (GUM) clinics in inner London. A total of 2482 questionnaires were returned (response rate 75%). A third of men (32%) reported having had unprotected anal intercourse in the previous year and 18% had done so with one or more partners of unknown or different HIV status. High risk sexual behaviour was associated with younger age, having casual partners, and recruitment from GUM clinics. The combination of high levels of both sexual risk behaviour and HIV prevalence demonstrates the need for sustained and innovative health promotion campaigns among homosexual men in London.
Adult↗