Variation In Time Of Onset Research Articles

Assessment of the anesthetic effect of modified pentothal sodium solution on Sprague-Dawley rats.

Clinically, pentothal sodium has been widely used for primary and general anesthesia induction. Also, it has been used to effectively inhibit convulsion. Pentothal sodium has a strong inhibitory effect on the respiratory center, excessive drug administration, and rapid dose rate that cause death of experimental animals on the respiratory depression. This study used a modified pentothal sodium solution to investigate its anesthetic effect. The pentothal sodium solution was modified based on pentothal sodium upon additions of magnesium sulfate, propylene glycol, and pure ethanol. The anesthetic effect of the modified pentothal sodium on Sprague–Dawley (SD) rats was investigated by comparing traditional pentothal sodium and ketamine; 60 SD rats were randomly divided into three groups. Each group was treated with traditional pentothal sodium, modified pentothal sodium, or ketamine, respectively, via intraperitoneal injection. The symptoms of experimental rats were observed, and onset time and anesthetic time were both recorded. The data were analyzed using statistical software. There were no significant differences in onset time and anesthetic time between the three groups. The variation of onset time and anesthetic time of the group treated with modified pentothal sodium was shorter than that of the other two groups. Furthermore, the number of anesthetic rats after the first injection was significantly higher than that of the other two groups. The modified pentothal sodium is capable of providing a stable anesthetic effect. The function and effect are much better than traditional pentothal sodium and ketamine.

Plasticity in diurnal activity and temporal phenotype during parental care in European starlings, Sturnus vulgaris

We used an automated radiotelemetry system to determine diurnal patterns of activity and temporal phenotype (onset and cessation of activity) in female European starlings during breeding. Parental care is thought to be the most ‘costly’ part of reproduction, with high rates of intense activity due to foraging and provisioning for chicks, so we predicted that variation in timing of activity should be closely related to breeding success. Diurnal variation in activity varied systematically with breeding stage in a way consistent with specific demands of each phase of parental care: incubating females were more active late in the day (1600–1800 hours), while chick-rearing females were more active early in the morning (0700–1100 hours). There was marked individual variation in timing of onset, and to a lesser extent cessation, of activity, e.g. chick-rearing females first became active 7–127 min after morning civil twilight, with low to moderate repeatability within and among breeding stages (individual explained 2–62% of total variation). On average, females were active later, and ceased being active earlier, during chick rearing compared with incubation. Chick-rearing birds had a longer active day, but only by 2.3% (36% of the seasonal increase in total available daylength). Thus, chick-rearing females were relatively less active (‘lazier’), which is consistent with the idea that parents work more efficiently rather than simply working harder. We found little evidence that chick-rearing activity was associated with variation in measures of current reproduction (provisioning rate, number and quality of chicks), future fecundity (initiating a second brood, cumulative 2-year productivity) or survival (local return rate). Our study demonstrates that time-keeping mechanisms show plasticity in response to reproductive state and can be modulated by ‘biotic’ (e.g. prey availability) or ‘social’ time (demands of parental care).

Neurodegenerative Interplay of Cardiovascular Autonomic Dysregulation and the Retina in Early Multiple Sclerosis.

Introduction: Autonomic nervous system (ANS) symptoms are prevalent in multiple sclerosis (MS) as is neurodegeneration. Our aim was to explore the occurrence of ANS symptoms and retinal neurodegeneration in a newly diagnosed MS population with tools available in a clinical setting.Methods: Forty-three MS patients and 44 healthy controls took part in the study. We employed a bedside cardiovascular ANS test battery together with classical pupillometry, optical coherence tomography (OCT) evaluation of retinal neurodegeneration in eyes without previous optic neuritis (MSNON) and patients' self-report forms on fatigue, orthostatic and ANS symptoms.Results: Half of the patients presented with ANS symptoms and a high level of fatigue. There was a significant difference in ganglion cell layer thickness (mean GCIPL) evaluated by OCT in MSNON compared to healthy control eyes. We found a negative linearity of mean GCIPL on group level with increasing disease duration. Three patients fulfilled the criteria of postural orthostatic tachycardia syndrome (POTS).Conclusion: Our results demonstrate retinal neurodegeneration in MSNON, a high frequency of fatigue and a high prevalence of ANS symptoms in newly diagnosed patients. Whether neurodegeneration precedes ANS dysfunction or vice versa is still open to debate, but as unveiled by the presence of POTS in this MS population, differences in stress-response regulation add to the understanding of variation in onset-time of ANS dysfunction in early MS.

Pattern of dengue virus infections in adult patients from Sri Lanka.

Sri Lanka experienced its largest dengue epidemic in 2017. This study describes the disease pattern of adult dengue patients from two hospitals in Sri Lanka. Demographic, clinical and investigation findings of adult dengue patients admitted to the two hospitals from June to August 2017 were collected and analysed. A total of 1167 patients (777 males [66.2%], mean age 32.9 y) were studied. There were 775 (66.4%) patients with dengue fever (DF), 334 (28.6%) with dengue haemorrhagic fever grade I, 54 (4.6%) with DHF grade II and 4 (0.3%) with DHF grade III. DHF was significantly associated with abdominal symptoms/signs and bleeding manifestations (p<0.001). A considerable variation in time of onset of the critical phase was noted (day 3, 11.9%; day 4-5, 63.1%; day 6, 16.2%; day ≥7, 8.7%). Significantly lower platelet and white blood cell counts and elevated transaminase levels were found in DHF than DF (p<0.001). Other complications included myocarditis (two patients) and mild renal impairment (three patients). None had neurological manifestations. We found abdominal symptoms/signs, low platelet and white blood cell counts and high transaminase to be associated with DHF. The onset of the critical phase was variable and difficult to predict. Compiling data from various regions would help to understand disease patterns, which in turn would help in formulating evidence-based management guidelines and the allocation of limited health care resources.

Determination of the 95% effective dose values of rocuronium bromide in epilepsy patients

Objective This study was to determine the values for 95% effective dose(ED95) of rocuronium in epilepsy patients. Methods Fourty epilepsy patients between 18 and 65 years of age, with ASA physical status classicfication Ⅰ or Ⅱ, undergoing elective surgery were enrolled. All patients were randomly divided into four groups(n=10) and were received (120, 180, 240 μg/kg and 300 μg/kg) rocuronium respectively. Neuromuscular monitoring of the ulnar nerve consisted of surface electrode stimulation and force transduction of the adductor pollicis muscle. Neuromuscular block was assessed by the percentages of maximum suppression in T1 of train of four stimulation(TOF). The data of maximum suppression in T1 were transformed into probit and dosage of rocuromium were transformed into logarithm. The onset time of rocuromium was recorded. The dose-effect curve of rocuronium was set up with linear regression method. And the ED95 value of rocuromium was calculated. Results There was not a significant variation in onset time among four groups(P>0.05). The maximum suppression in T1 were increased in group of higher dose(P 0.05). The ED95 value of rocuromium in epilepsy patients is 445.3 μg/kg, and that was higher than normal people with 300 μg/kg ED95 value(P<0.05). Conclusions The ED95 value of rocuromium in epilepsy patients is higher than non-epilepsy patients. The present data support the larger dose rocuronium is needed in epilepsy patients. Key words: Epilepsy; Rocuronium; 95% effective dose

Same Pattern of Circadian Variation According to the Season in the Timing of Ischemic Stroke Onset: Preliminary Report

Background and ObjectiveaaStroke occurrence shows a chronobiological variation, which is considered to be related with waking in the morning. We hypothesized that its seasonal difference would also exist because individual life activity including sleep-wake pattern can be influenced by interseasonal variability. The objective of this study was to investigate the seasonal difference of circadian variation in the timing of onset in patients with acute ischemic stroke. MethodsaaWe studied 1486 patients with acute ischemic stroke. Stroke onset time was defined as the earliest time the patient or a wit ness noted definite neurological symptoms. The patients with clear onset stroke were enrolled. Frequency of onset was analyzed for four 6-hour and twelve 2-hour intervals from 0 to 24 hour per day. ResultsaaThe clear onset time was known in 968 patients (65.1%). Mean age of the patients was 67.63 ± 12.65 years and 589 patients (60.9%) were male. Stroke occurred in spring (26.5%), summer (27.2%), fall (24.1%), and winter (22.3%). In all cases, ischemic stroke showed a significant circadian variation in time of onset (p < 0.001). High peak period was between 6:01 AM to 12:00 PM (37%) with the same pattern in each season. ConclusionsaaSeasonal difference was not significant despite circadian variation in time of onset of ischemic stroke. Thus, exogenous factors such as environmental factors and life styles may have less influence on inter-seasonal variability of circadian rhythms, which are related with chronobiological factors of stroke onset in this regional population.

Onset of intractability and its course over time: The Dutch study of epilepsy in childhood

Intractability in epilepsy is difficult to define, and little is known about its onset, course, and duration. We investigated these aspects (as well as the occurrence of intractability) during long-term follow-up in patients with epilepsy, focusing on possible explanations for the variation in time of onset and duration of intractability. After diagnosis, 453 patients with childhood-onset epilepsy had a 5-year follow-up with regular visits and data collection. Ten years later they received a questionnaire with items concerning epilepsy, which was completed by 413 patients resulting in a mean follow-up of 15 years. Intractability during the first 5 years was compared with that in the last year of follow-up. Intractability was defined as having no 3-month remission during a 1-year period despite adequate medical treatment. At least 12.1% of the cohort had a period of intractability during the 15-year follow-up, and 8.5% were intractable in the final year. Of the patients with idiopathic etiology 4.3% had a period of intractability versus 17.0% for those with cryptogenic, and 22.6% for those with remote symptomatic etiology (p < 0.001). Other risk factors at baseline were younger age at first seizure, generalized cryptogenic/symptomatic or localization-related symptomatic epilepsy, mental retardation, and febrile convulsions before enrollment. The cumulative risk of a period of intractability was 6.1% (95% confidence interval [CI] 3.7-8.5) at 2 years follow-up and 8.2% (95% CI 5.4-11.0) at 5 years. The mean time to onset of intractability during the first 5 years of follow-up was 1.6 (95% CI 1.3-2.0; median 1.0) years and the mean duration of intractability during these 5 years was 3.3 (95% CI 2.8-3.8; median 3.6) years. Fifteen patients were intractable only during the first 5 years of follow-up (group A), and 19 subjects were intractable both during the first 5 years and the last year of follow-up (group B). Compared with group A, group B had shorter remission and a longer time to intractability during the first 5 years and more were intractable in the fifth year of follow-up. Sixteen other patients had a late onset of intractability after 5 years of follow-up, sometimes after long periods of remission (group C). No significant differences in baseline characteristics were found among groups A, B, and C, but slightly more children in groups B and C became mentally retarded during the follow-up. In all groups, antiepileptic drugs were of little use in preventing and ending intractability. There is a large unpredictable variation in time of onset, course, and duration of intractability, with a higher chance of final intractability after a poor course during the first 5 years of follow-up. The natural course of epilepsy probably best explains the variable course of intractability. The effect of medication seems to be minor.

Circadian variation in the timing of stroke onset: a meta-analysis.

Acute myocardial infarction and sudden death display a circadian rhythm, with a higher risk between 6 AM and noon. Some reports suggest that stroke does not follow such a circadian variation and that hemorrhagic stroke occurs more often during the evening. A meta-analysis of 31 publications reporting the circadian timing of 11,816 strokes was performed, subdividing (when possible) by the type of stroke, according to the time of onset of symptoms. When precise timing was not given, strokes were distributed evenly (that is, biasing toward the null hypothesis of lack of circadian variation). All subtypes of strokes displayed a significant (P<0.001) circadian variation in time of onset, whether divided into 3-, 4-, or 6-hour time periods. There was a 49% increase (95% confidence interval, 44% to 55%) in stroke of all types between 6 AM and noon (compared with expectations if no circadian variation was present), which is a 79% (95% confidence interval, 72% to 87%) increase over the normalized risk of the other 18 hours of the day. There were 29% fewer strokes between midnight and 6 AM, a 35% decrease compared with the other 18 hours of the day. All three subtypes of stroke had a significantly higher risk between 6 AM and noon (55% for 8250 ischemic strokes; 34% for 1801 hemorrhagic strokes, and 50% for 405 transient ischemic attacks). These data support the presence of a circadian pattern in the onset of stroke, with a significantly higher risk in the morning.

Atypical (non-diarrhea-associated) hemolytic-uremic syndrome in childhood

We describe the clinical and laboratory features of 20 children who were seen during the past 20 years with idiopathic nondiarrhea-associated hemolytic-uremic syndrome. There was no seasonal variation in time of onset; a genetic pre-disposition seemed likely in two of the cases. The prodromal illness was nonspecific and by definition did not include diarrhea. Hypertension was a major problem in the majority of the patients. Five died, three during the initial illness; four are in end-stage renal failure, and all but two of the survivors have residual nephropathy. Eleven patients had a "relapsing" course; up to eight additional documented episodes of hemolytic-uremic syndrome occurred in individual patients. Of the nine children treated before 1980, three died shortly after onset, two never recovered function after the initial illness, one had a relapsing course and died later, and one had residual nephropathy. Plasma exchange was introduced for the management of non-diarrhea-associated hemolytic-uremic syndrome in 1980; since then, all of the 11 patients have recovered function after the initial episode, but 10 of them had relapses. It appears that with the introduction of plasma exchange there has been an improved outcome in the initial phase, but the survivors tend to have relapses. Atypical (non-diarrhea-associated) hemolytic-uremic syndrome is a heterogeneous yet distinct subgroup of hemolytic-uremic syndrome that differs from diarrhea-associated hemolytic-uremic syndrome on epidemiologic, clinical, laboratory, histologic, and prognostic grounds.

Effect of activity on circadian variation in time of onset of acute myocardial infarction

There is a circadian variation in the onset of acute myocardial infarction (AMI) with the peak incidence occurring between 6:00 a.m. and 12:00 a.m. Muller et al 1 proposed that this increased frequency of AMI in the morning is due to the circadian variation of potential triggers of plaque rupture and development of occlusive thrombosis. These potential triggers of AMI include morning surges of cortisol and catecholamines, increases in blood pressure and heart rate, as well as increases in platelet aggregability, 2 blood viscosity, 3 and vasomotor tone in conjunction with diminished fibrinolytic activity. 4 The peak incidence of AMI occurs somewhat later in the morning (10:00 a.m. to 12:00 a.m.) than the peak activity of most of the potential triggers that occur between 6:00 a.m. and 9:00 a.m. 5 Exertion enhances the potential adverse effects of all these potential triggers of AMI. Thus, we hypothesized that baseline resting circadian variation of potential triggers of AMI would have the greatest effect on AMI occurring in the absence of exertion. If this hypothesis is correct, AMI not associated with exertion would have a peak incidence coinciding more closely with the peak adverse effects of the potential triggers in the early morning. Accordingly, this study was undertaken to evaluate prospectively the influence of activity at the onset of AMI to the circadian variation in the time of onset of AMI.

Pharmacodynamics of the initiation of antiarrhythmic therapy with lorcainide

Lorcainide is an antiarrhythmic drug with unusual pharmacokinetics and an active metabolite, norlorcainide, which complicate oral drug loading. In order to characterize the accumulation of lorcainide and norlorcainide and to define the onset of antiarrhythmic action during lorcainide loading, 9 patients with frequent ventricular ectopic beats were studied. During lorcainide loading with 100 mg orally twice daily, frequent ambulatory electrocardiographic recordings were monitored and blood samples for drug concentrations were determined. There was a 10-fold range of intersubject variation in plasma concentrations. Despite a half-life of only 8.9 ± 2.3 hours, lorcainide did not reach steady state until after 4.5 days of therapy. Norlorcainide had a hal-flife of 26.5 ± 7.2 hours and was estimated to come to steady state after 7 to 10 days. There was considerable intersubject variation in time of onset of antiarrhythmic response (2 to more than 4.5 days) and a 4- to 5-fold range of intersubject variation in threshold therapeutic plasma concentration (lorcainide 40 to 200 ng/ml, norlorcainide 80 to 300 ng/ml). These observations suggest that lorcainide should be started at low doses and the dose should not be increased more frequently than once a week.

The pathogenesis of propranolol-withdrawal syndrome in essential hypertension.

1. In hypertension, the beta-adrenoreceptor-blocker-withdrawal syndrome comprises tachycardia, sweating, tremor and general malaise, symptoms resembling thyrotoxicosis. 2. The effect of abrupt cessation of propranolol on serum concentrations of thyroxine (T4) and triiodothyronine (T3) was therefore investigated in five patients with uncomplicated essential hypertension, treated with propranolol in doses from 160 to 480 mg/day. 3. Four of the five patients developed one or more of the above-mentioned symptoms within 2-6 days after withdrawal of propranolol. 4. A mean relative increase in serum free T3 of 51% (range 22-74%) was found in these four patients on the day of onset of symptoms. 5. The increase in free T3 in the five patients correlated positively with total serum propranolol on the last day the drug was given (r = 0.91, 2P = 0.03). 6. As an increase in T3 was found only in patients suffering the withdrawal syndrome, and was maximal the day the symptoms appeared, despite a variation in time of onset from 2 to 6 days, it is suggested that the beta-adrenoreceptor-blocker-withdrawal syndrome, at least partially, is caused by rebound increased production of T3, induced by the well-known inhibition of the monodeiodination of T4 to T3 during beta-adrenoreceptor blockade. 7. This assumption may explain the clinical symptoms and the reported transient increased beta-adrenoreceptor sensitivity with unchanged serum concentrations of catecholamines.

Ovulatory activity in mature Romney ewes in New Zealand

Causes of variation in time of onset and levels of ovulatory activity were studied in 7,782 mature Romney ewes from several regions within New Zealand in 1959, 1960, and 1962. The median date of on...

Synchronization of oestrus in sheep by orally active progesterone derivative

In a preliminary experiment with 40 Merino ewes of 45 kg liveweight, oral doses of 0, 6.6, 20, and 60 mg 6-methyl-17-acetoxyprogesterone were administered daily for 14 days. The highest dose level completely prevented oestrus during treatment, and all 10 ewes came into oestrus during the 5-day period beginning 24 hr after the last dose; seven of the 10 ewes conceived and lambed. Daily doses of 6.6 and 20 mg reduced the incidence of oestrus during treatment, but produced little synchronization subsequently. In the main experiment 77 similar ewes were treated over 17 days with either 6-methyl-17-acetoxyprogesterone (50 mg orally per day, 39 ewes), or progesterone (10 mg in oil intramuscularly every second day, 38 ewes). There were 19 untreated ewes. Some ewes from each group were marked by rams during the treatment period. In the 6 days following the final dose of progestagen 75% of ewes were marked by rams, with a peak on the third day. There was no difference between treatments. The proportion of ewes that lambed following mating in the 6 days after cessation of treatment was 15/29 and 11/29 for 6-methyl-17-acetoxyprogesterone and progesterone treatments respectively. In the main experiment half the ewes were injected with pregnant mare serum gonadotrophin 24 hr after the last dose of progestagen, and 24 hr later, with human ohorionic gonadotrophin. This supplementary treatment did not further reduce inter-animal variation in time of onset of oestrus, but tended to reduce the proportion of ewes exhibiting oestrus.