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PubMed1997

Detection of mineral density on the surface of mouse parietal bones: backscattered electron imaging of low accelerating voltage scanning electron microscopy.

Backscattered electron (BSE) imaging of scanning electron microscopy (SEM) was applied to a study on the mineral density of the bone surface. The neonatal and adult mouse parietal bones freed of the periosteum and covering cells were examined in a field emission scanning electron microscope equipped with a high sensitivity BSE detector at 1-30 kV accelerating voltages. The mineral density of the bone surface was observable in BSE images at 5 kV accelerating voltage while only the topographic structures of the surface were obtained under an accelerating voltage less than 5 kV. As the accelerating voltages increased from 5 kV, the bright areas were extended, probably due to the imaging of the calcified bone matrix under the uncalcified osteoid. The bone surface is usually divided into smooth and rough areas according to its irregularities. BSE images at 5 kV clearly showed that the smooth areas were further divided into dark and bright areas which apparently corresponded to the uncalcified osteoid and calcified bone matrix, respectively. Bright granules, about 1.0-3.0 microns in diameter, were sometimes observed at the border between the osteoid and calcified bone matrix; these granular calcified areas were regarded as the calcifying front forming the calcified bone matrix from the osteoid. The present study demonstrated that the distribution of the osteoid on the mouse parietal bone surface changes depending on age: the osteoid occupied a large area in the parietal bone surface in neonatal mice, but was small in adult mice. Thus, low accelerating voltage SEM using BSE provides new information on the distribution of the osteoid and the bone matrix calcification under both normal and pathological conditions.

Aging↗

PubMed2003

The place of accelerated schedules for hepatitis A and B vaccinations.

The availability of accelerated schedules of vaccination, as well as the development of combination vaccines, has enhanced the methods of protection against infectious disease, in particular that of hepatitis A and B viruses. The benefits of using accelerated schedules include: (i) enhanced adherence to and subsequent completion of vaccine courses; (ii) convenience for the recipient of the vaccine; (iii) reduced administration costs of providing the vaccine; and, most importantly, (iv) the ability to provide protection against these serious infections to those who will be imminently exposed to the risk and so require protection as quickly as possible. Active immunisation against both hepatitis A and B viruses has only been recognised within the last 20 years. During this time clinical studies have demonstrated the safety and efficacy of administering the monovalent hepatitis B vaccine by way of accelerated schedules. There are now several accelerated schedules of administration of hepatitis B vaccine which can be tailored to the needs of the individual at risk of exposure to infection. One such schedule allows the primary course to be administered within a period of 1 month. This schedule of day 0, 7 and 21, with a booster at 12 months, is licensed for use with the recombinant hepatitis B vaccine Engerix B and results in a seroprotection rate of 65% at day 28 which increases to 99% at month 13. In more recent years, the development of a multivalent or combination vaccine against hepatitis A and B (Twinrix) has been a welcome advance in the protection against viral hepatitis, and has been of particular benefit to those who are at risk of infection with both viruses. The advantages of accelerated schedules have also been recognised with this combination vaccine. The primary course may be administered within a period of 1 month so providing protection for those at risk and, in particular, the last minute traveller.

Adolescent↗

PubMed2003

Age-related accelerated tapping response in healthy population.

Different types of rapid tapping responses were described in the finger-tapping test. The "Hastening phenomenon" was described as an abnormal motor response in patients with Parkinson's disease. Accelerated tapping has been shown in a healthy elderly sample. It is not clear whether accelerated tapping relates to the hastening phenomenon or characterizes normal aging. We hypothesized that this sample of 21 healthy elderly people showed increased accelerated tapping but not hastening phenomenon. To assess this hypothesis, 20 healthy young and 21 elderly subjects performed a tapping test, requiring responses from 1 to 6 Hz. The healthy elderly sample showed increased accelerated tapping but not increased "hastening phenomenon." We conclude that Accelerated tapping may represent age-related motor processes unlike the hastening phenomenon characterizing Parkinson's disease.

Adult↗

PubMed1988

Accelerated versus conventional fractionation. The degree of incomplete repair in human skin with a four-hour-fraction interval studied after postmastectomy irradiation.

A previously presented clinical assay with postoperative irradiation to bilateral parasternal fields in patients with breast cancer was used for a comparison of acute and late reactions in human skin after accelerated and conventional fractionation. Two and 3 fractions per day at 4-hour intervals were compared with one fraction per day. Dose fractions of about 2 Gy were used. Twenty-five fractions were given in 2.5, 1.5 and 5 weeks respectively. The acute reactions were similar regardless if 1, 2 or 3 fractions per day were given, i.e. equal total doses were isoeffective. The repair of intracellular damage was apparently completed within 4 hours. However, this might not be true due to a differential influence of proliferation and redistribution on the effect of different types of fractionation, which makes it difficult to interpret the result and estimate the degree of intracellular repair. The time to the acute peak reaction was shortened by 6 to 7 days with accelerated compared to conventional fractionation, explained by the differences in the dose delivery rates. Consequently, the onset of a compensatory proliferation is earlier after accelerated fractionation. Late reactions were more pronounced after accelerated than after conventional fractionation and 1 X 2.0 Gy/day was found to be equivalent to 2 X 1.80 Gy/day and 3 X 1.65 Gy/day at 4-hour intervals with an equal fraction number for all 3 schedules. Assuming that proliferation is negligible for late responding tissues, we interpret this finding as an expression of the degree of reduced intracellular repair. Finally, we would like to point out that the iso-effect dose relationships between acute and late reactions for accelerated versus conventional fractionation might vary, above all with the cell proliferation kinetics of acutely reacting tissue.

Breast Neoplasms↗

PubMedDate not supplied

Accelerated rehabilitation after proximal femoral fracture: a randomized controlled trial.

This randomized controlled trial compared accelerated rehabilitation after surgical treatment of proximal femoral fracture with conventional care and was conducted in a general hospital in an outer urban area. Participating were 261 sequentially admitted patients over the age of 50 years who met predetermined inclusion criteria and all were followed up until death or 4 months after fracture. Patients who were treated with the accelerated rehabilitation programme had a 20% reduction in length of hospital stay. Improved physical independence (as measured by Barthel Index) was observed after fracture in accelerated rehabilitation programme patients with limited pre-existing disability. Non-nursing-home patients receiving accelerated rehabilitation were also less likely to be discharged to nursing-home care or die in hospital. Accelerated rehabilitation led to a substantial reduction in length of hospital stay with a modest short-term improvement in level of physical independence and accommodation status after discharge.

Activities of Daily Living↗

PubMed1999

The effects of accelerated growth rates and estrogen implants in prepubertal Holstein heifers on growth, feed efficiency, and blood parameters.

Sixty-eight Holstein heifers were used to determine the effects of accelerated growth rates by increased nutrient intake and estrogen implants on feed efficiency, structural growth, and blood parameters in heifers between 19 and 39 wk of age. At the beginning of the treatment period, the heifers were assigned to one of four treatment groups by using a randomized complete block design in a 2 x 2 factorial arrangement. The treatments were standard growth rate (700 g/d), accelerated growth rate (1000 g/d), standard growth rate with an estradiol implant, and accelerated growth rate with an estradiol implant. All heifers received the same diet, but dry matter intake was adjusted weekly to achieve the target rate of gain. Accelerating heifer growth rates from 705 to 1007 g/d improved feed efficiency 5.1%, increased the rate of withers height, heart girth, and hip width growth 12, 27, and 27%, respectively, and body condition scores 0.25 points. Estradiol implants improved feed efficiency 2.4% and decreased the rate of withers height 6% and heart girth growth 3.5%. Increased nutrient intake and average daily gain depressed mean plasma growth hormone and urea nitrogen content 17 and 7%, respectively, while elevating insulin-like growth factor-1 levels by 10%. Estradiol implants increased mean plasma growth hormone content by 29% and insulin-like growth factor-1 levels by 17%, but decreased urea nitrogen content by 11%. Feeding prepubertal heifers for accelerated growth rates increased structural growth with a small increase in body condition, whereas estradiol implants improved feed efficiency and decreased the growth rate of withers height and heart girth without affecting the rate of hip width growth.

Animal Nutritional Physiological Phenomena↗

PubMed1999

The effects of accelerated growth rates and estrogen implants in prepubertal Holstein heifers on estimates of mammary development and subsequent reproduction and milk production.

The objectives of this study were to determine the effects of accelerating growth rates and of imposing estrogen implants in prepubertal heifers on mammary development and subsequent reproduction and milk production. Sixty-eight Holstein heifers were assigned to 1 of 4 treatment groups by using a randomized complete block design in a 2 x 2 factorial arrangement. The treatments were standard growth rate (700 g/d) or accelerated growth rate (1000 g/d) and estrogen implant or no estrogen implant. The treatments were imposed over 20 wk, beginning at 4.5 mo of age and 130 kg of body weight (BW). During the treatment period, all heifers were fed individually and received the same diet, but the dry matter intake of each heifer was adjusted weekly to achieve the designated growth rate. The estrogen implants were removed at the end of the treatment period at 9.5 mo of age. After the treatment period, the heifers were group fed according to BW and age to allow the heifers to have a similar BW and age at calving. The accelerated growth regimen decreased age at puberty by 32 d. Age, BW, and body condition scores at calving were not significantly different among treatments. The accelerated prepubertal growth regimen decreased first lactation fat-corrected milk yield 7.1%. Prepubertal heifers given estrogen implants produced 5.2% less fat-corrected milk during first lactation than did heifers not implanted with estrogen. Estrogen implants stimulated a large increase in teat length growth during the treatment period, but the advantage was lost posttreatment. Over both the treatment and posttreatment periods, the estrogen implants reduced teat length growth by 30%. Accelerated growth rates from 700 to 1000 g/d and estrogen implants in prepubertal heifers decreased first lactation milk production.

Aging↗

PubMed2000

Long-term experience with an accelerated protocol for diagnosis of chest pain.

CONTEXT: More than 6 million patients present annually with chest pain suggestive of acute coronary syndrome. Rapid and accurate diagnosis is essential for best clinical outcomes, for optimal management of hospital resources, and for minimizing medicolegal exposure. OBJECTIVE: To evaluate the clinical and cost outcomes of an accelerated protocol for chest pain triage in a community-based hospital of moderate size. METHODS: One hundred successive patients with chest pain were diagnosed according to the Traditional Chest Pain Protocol, which included testing of serial blood samples for creatine kinase (CK)-MB and total CK. These patients were also subjected to the Accelerated Chest Pain Protocol under evaluation, which included testing at shortened intervals for myoglobin and cardiac troponin I in addition to CK and CK-MB. Diagnostic sensitivity and specificity were compared versus the final assigned diagnosis. The Accelerated Chest Pain Protocol was implemented for routine use. Follow-up evaluations were conducted at 1 month (test group A, N = 180) and 22 months (test group B, N = 180). Costs for diagnosis and treatment of the 2 test groups were compared with those for the control group. RESULTS: The 2 protocols had equivalent specificity values (99%). The sensitivity of the Accelerated Chest Pain Protocol was higher than that of the Traditional Chest Pain Protocol (95% vs 58%). Cost savings of 29% and a reduction in length of stay of 33% were achieved in test group B versus the control group. CONCLUSIONS: The Accelerated Chest Pain Protocol improved the accuracy and timeliness of diagnosis of acute coronary syndrome while reducing costs.

Aged↗

PubMed2000

Roles of endogenous prostaglandins and nitric oxide in inhibitions of gastric emptying and accelerations of gastrointestinal transit by escins Ia, Ib, IIa, and IIb in mice.

We reported previously that escins Ia, Ib, IIa, and IIb, isolated from horse chestnuts, inhibited the 30-min gastric emptying (GE) in mice. In this study, the effects of escins Ia-IIb on gastrointestinal transit (GIT), and the roles of endogenous prostaglandins (PGs) and nitric oxide (NO) in the effects of escins Ia--IIb on GE and GIT were investigated in fasted mice. Escins Ia-IIb (12.5-50 mg/kg, p.o.) dose-dependently accelerated GIT. Both GE inhibitions and GIT accelerations by escins Ia-IIb (25 mg/kg) were markedly attenuated by pretreatment with indomethacin (10 mg/kg, s.c., an inhibitor of PGs synthesis). Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg, i.p., an inhibitor of constitutive and inducible NO synthase) attenuated the effects of escins Ia-IIb on GIT, but not on GE. The effect of L-NAME was reversed by L-arginine (600 mg/kg, i.p., a substrate of NO synthase), but not by D-arginine (900 mg/kg, i.p., the enantiomer of L-arginine). The GIT accelerations of escins Ia-IIb were not attenuated by pretreatment with D-NAME (10 mg/kg, i.p., the enantiomer of L-NAME) or dexamethasone (5 mg/kg, i.p., an inhibitor of inducible form of NO synthase). The results suggest that endogenous PGs play an important role in both GE inhibitions and GIT accelerations, and constitutive NO is involved in the GIT accelerations, by escins Ia--IIb in mice.

Animals↗

PubMed2000

[Accelerated titration design].

To reduce the number of patients treated at low and biologically inactive doses in phase I trials of anticancer agents, attempts to decrease the number of patients per dose level and to conduct a larger dose escalation have been made. Among them, accelerated titration designs were proposed and evaluated by simulation; designs 2 and 4 were reported to be acceptable (J Natl Cancer Inst 89: 1138-1147, 1997). Both designs 2 and 4 included only one patient per cohort during the initial accelerated phase. Dosage steps for the accelerated phase were defined using the modified Fibonacci method for design 2 and 100% escalation for design 4, respectively. The accelerated phase continued until one patient experienced dose-limiting toxicity or two patients experienced grade 2 toxicities. Dose escalation was conducted based on the information from the first course in design 2 and from the first three courses in design 4. In the simulation, both designs successfully reduced the total number of patients and the number of undertreated patients without increasing the number of overtreated patients. However, the safety of design 4 was assured as long as all patients received three courses of chemotherapy, which is unusual in phase I studies in Japan. Decision-making on dose escalation based on the information on toxicity in three courses might be cumbersome. Therefore, in Japan, design 2 would be recommended among the proposed accelerated designs. The performance of the design should be investigated by applying it to actual phase I studies and by evaluating the number of undertreated and overtreated patients.

Antineoplastic Agents↗

PubMed1975

Temporal relationships critical to progesterone-induced acceleration of ovum transport.

Previous investigators have demonstrated that 2.5 mg fo progesterone, administered intramuscularly to rabbits on the day of ovulation and the 2 preceding days (Days -2, -1, and 0) significantly and consistently accelerates ovum transport. In contrast, when given on the day of ovulation and the 2 following days (Days 0, +1, and +2), progesterone does not accelerate ovum transport. The experiments reported were designed to define more precisely the temporal relationships critical to progesterone-induced acceleration of tubal ovum transport. Our observations suggest 3 important conclusions: 1) Progesterone, when given at least 1 day, and not more than 2 days, prior to ovulation does induce accelerated ovum transport. 2) The progesterone responsive mechanism is dose dependent. 3) The acceleration is partially antagonized if progesterone treatment is begun 3 days prior to ovulation.

Animals↗

PubMed2003

Contrast sensitivity after +Gz acceleration.

BACKGROUND: This study was designed to determine the extent and duration of contrast sensitivity (CS) loss after high sustained +Gz acceleration in a centrifuge. METHODS: The subjects were 12 healthy male flight surgeons between 20 and 22 (mean = 21.1) yr of age. The human centrifuge at the Aviation Physiology Research Laboratory in Tainan, Taiwan, was used to expose the subjects to an acceleration profile. Each subject experienced three centrifuge runs made up of one gradual onset and two rapid onset profiles. Contrast sensitivity (CS) was measured before, and at 5 min, 10 min, and 20 min for the right eye; and 7 min, 12 min, and 22 min for the left eye after the acceleration. Both eyes were measured with the right eye being tested first. RESULTS: There was a generalized depression of CS at 5-12 min for both eyes. The depression was more severe at low and medium frequencies (1.5, 3.0, 6.0 cycles per degree, cpd) than at a high spatial frequency (18.0 cpd). There was a significant decrease in CS of the right eye at 1.5 cpd (p < 0.05 between control and 5 min), and on the left eye at 3.0 cpd (p < 0.05 between control and 7 min, p < 0.05 between control and 12 min) and 6.0 cpd (p < 0.05 between control and 12 min). The CS loss was more obvious at 5-12 min for both eyes, and there was only partial recovery at 22 min after the acceleration. CONCLUSIONS: These results demonstrated that +Gz acceleration is associated with CS loss. The recovery time was greater than expected. Factors other than ocular blood flow may be involved in the prolonged CS loss.

Adult↗

PubMed2005

[Correlations of anthropometric and psychodynamic indexes of accelerant boys and girls (georgians) and their comparing with the data of women and men of normal physical development].

Our goal was to determine relations of anthropometric and psychodynamic indexes of accelerant women and men (Georgian) and compare them with the data of women and men of normal physical development. For this reason we have investigated 100 accelerants -- 45 girls and 55 boys. On the basis of our study we have shown that correlations between subspecies of temperament and anthropometrical signs in accelerant women and men are equal or lower among men. From the point of view of character form -- these data in women are comparatively high, and correlation of intellect and types of mood and anthropometric signs are equal. In comparison with the men of normal development, in accelerant men are noticed law interconnection between anthropometrical and psychodynamic data except subspecies of intellect, which is equal in every case. Connection between the types of mood and anthropometric data are moderate (in the limits 0.3-0.4). Men accelerants (Georgians) are brachymorphic somatotypes; they are distinguished by phlegmatic temperament, introversion, middle logic intellect, conflict -- statistic mood; according to the mood they are harmonic-dynamic constitutional types.

Adult↗

PubMed1990

Accelerated arteriosclerosis in heart transplant recipients is associated with a T-lymphocyte-mediated endothelialitis.

Accelerated arteriosclerosis has emerged as a major life-threatening complication in long-term survivors of heart transplantation. It has been proposed that accelerated arteriosclerosis is an immune-mediated complication of rejection. We observed a striking endothelialitis in the coronary arteries of two explanted hearts obtained from patients with severe transplant-related accelerated arteriosclerosis. This finding prompted us to review the pathologic changes in the coronary arteries of 23 autopsied patients who had received heart transplants. The infiltrate in these vessels was characterized using immunohistochemical stains for lymphocytes (CD45), macrophages (MAC-387), T lymphocytes (CD45RO), B lymphocytes (L-26), and smooth muscle cells (actin). In addition, a full panel of monoclonal antibodies was used on the fresh-frozen tissue available from one of the two explanted hearts. Ten of the eleven recipients with accelerated arteriosclerosis had a moderate to marked lymphocytic endothelialitis compared to 3 of 14 without transplant-related arteriosclerosis (P less than 0.005). Immunohistochemical staining of the paraffin-embedded material demonstrated that most of the lymphocytes in the subendothelial space of these vessels were T lymphocytes and that this infiltrate was associated with an accumulation of macrophages and a proliferation of smooth muscle cells in the intima. In the explanted heart from which fresh-frozen tissue was available for more detailed cell typing, the T cells marked predominantly as cytotoxic T lymphocytes (CD8+, CD2+). These results suggest that accelerated arteriosclerosis may be mediated, in part, by a cytotoxic T-lymphocyte-directed endothelialitis.

Adult↗

PubMed1991

Lenses of diabetic patients "yellow" at an accelerated rate similar to older normals.

The authors used a psychophysical method to measure lens transmission of young, type I diabetic patients and normal controls. The results from normal controls agreed with previously published reports of decreasing lens transmission with age, and those from diabetic subjects suggested that lenses of young, type I diabetic patients age or "yellow" at an accelerated rate that was similar to that of normal controls over the age of 60 yr. The rate of accelerated lens density that occurs per year with the duration of diabetes is similar to the rate of accelerated lens density that occurs per year with patient age over 60 yr. A possible molecular explanation for the accelerated lens yellowing in both populations is discussed. Both diabetic individuals and the older normal populations have elevated plasma glucose levels and therefore may have accelerated glycosylation of lens proteins which causes increased lens yellowing.

Adult↗

PubMedDate not supplied

Reflex-induced acceleration of mucociliary activity in rabbit after exposure to cigarette smoke.

Short-term exposure to cigarette smoke is known to accelerate mucociliary (m.c.) activity in the rabbit maxillary sinus and to increase m.c. clearance from the lung. Several components of cigarette smoke stimulate sensory C-fibre endings in the airways. Some of these fibres contain the neuropeptide substance P (SP), and release of SP after stimulation of C-fibre endings is thought to accelerate m.c. activity. The purpose of the present investigation was to study possible mechanisms responsible for the increase of m.c. activity in the rabbit maxillary sinus after exposure to cigarette smoke. When delivered once a minute, 2.5 ml smoke puffs each accelerated the m.c. activity, the maximal increase being 34.7 +/- 2.4%, with a latency of 3.7 +/- 0.5 s. The response to cigarette smoke was suppressed in rabbits pretreated with atropine, an SP antagonist [(D-Pro2, D-Trp7,9)SP], capsaicin or hexamethonium. A response, albeit reduced, elicited in atropinized rabbits indicated a non-cholinergic component. The atropine-resistant acceleration was abolished by the SP antagonist. Together the results suggest that cigarette smoke accelerates m.c. activity through a reflex involving sensory SP containing C-fibres (afferent pathway) and cholinergic (probably parasympathetic) effector neurones (efferent pathway). Hence, the effect of cigarette smoke on the m.c. system reflects the joint release of both SP and acetylcholine. This dual mechanism may be of importance in the regulation of m.c. activity.

Acetylcholine↗

PubMedDate not supplied

Effect of water load in human body systems upon tolerance to +Gz acceleration.

A possible improvement of +Gz acceleration tolerance, obtained in human subjects through administering specific volumes of water, viz. 7, 14 and 21 ml/kg body weight, to be drunk immediately before centrifuge examination in order to increase the volume of plasma, thus increasing the circulating blood volume, was the starting-point for this work. Two hundred healthy male subjects, aged 19.9 +/- 0.9, were classified in 4 main groups and 2 supplementary groups for examination. It was found that the water intake in volumes of 14 ml/kg body weight produced a significant mean increase in the acceleration tolerance of 0.8 G, and that of 21 ml/kg body weight improved acceleration tolerance by 1.1 G on the average. The increase tolerance to acceleration was maintained throughout a period of about 30 minutes (for 14 ml/kg body weight) up to approximately 50 minutes (for 21 ml/kg body weight). The favourable effect of water load in the body systems upon +Gz acceleration tolerance was probably due to the increase of plasma volume (by 5.24% and 6.98% for 14 and 21 ml/kg body weight, respectively).

Adult↗

PubMed1988

Factors that accelerate or retard red blood cell senescence.

This article explores information concerning alterations in the time of age-related red blood cell (rbc) death (rbc senescence) in experimental animals and humans. Those factors that accelerate or retard the mean time for senescent death [the mean potential rbc life-span, (T)] are discussed; specifically excluded are conditions in which rbc survival is shortened due to an increase in the rate of age-independent [random hemolysis, (k)]rbc death. The factors prolonging senescence are reduction in metabolic rate through hibernation, reduced environmental temperature, hypophysectomy and thyroidectomy, and splenectomy. In general, these processes prolong rbc senescence by about 10%-15% in the models studied to date. The failure of splenectomy to prolong rbc senescence to any physiologically meaningful extent casts serious doubt on the concept that splenic processes are a major factor in the senescence process. Rbcs made under conditions of increased erythropoiesis and/or increased metabolic rate show acceleration of senescence. Thus, rbcs of animals treated with thyroxine show a 15% acceleration of senescence. "Stress reticulocytes" and normal full-term human newborn rbc may show up to 25% reduction in (T). The maximum acceleration seen to date is 50%-90%, as seen in the rbcs of the fetal and newborn rat. rbc senescence is not accelerated in rats with splenomegaly and increased rates of random hemolysis, again casting strong doubts on the spleen's ability to alter rbc senescence by progressively modifying the rbc during successive passages through that organ. It is postulated that rbc senescence is mainly a function of the red cell's initial endowment, particularly in the dynamic ability of that cell (and its membrane) to adapt to cumulative stresses that exist during its circulation through the body.

Animals↗