Mobilisation after Achilles tendon rupture.
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Achilles Tendon↗
Biomedical subjects
P Roberts
Publications and source records attributed to P Roberts.
Initiation and duration of myogenic precursor cell replication in transplants of intact skeletal muscles: an autoradiographic study in mice.
Skeletal muscle fibers are capable of regeneration following ischemia, traumatic injury, or transplantation. Although the time course of the regenerative process has been studied in detail histologically, little is known about the time of activation of myogenic precursor cells which are primarily responsible for muscle regeneration. This study was designed to determine the initiation, peak proliferative activity, and cessation times of muscle precursor replication in small skeletal muscle transplants. Forty-eight young male BALB/c mice had the extensor digitorum longus muscles of both hind legs autotransplanted to a different site in the same leg. At various time intervals after transplantation (from 24 hours to 14 days), mice were injected once with a small dose of tritiated thymidine in order to label proliferating myogenic precursor cells. The transplants were allowed to regenerate for 14 days, before being removed, processed for autoradiography, and analysed by light microscopy. The presence of labelled myotube nuclei in regenerated transplants showed that myogenic precursors had been replicating at the time of tritiated thymidine injection. Myogenic precursor replication was initiated late on the second day (42-48 hours) after transplantation, peaked after 6 days, and was complete within 10 days.
Animals↗
Silver-stained structures (AgNORs), their dependence on tissue fixation and absence of prognostic relevance in rectal adenocarcinoma.
The value of a one-stage silver staining technique for nucleolar organizer region (NOR)-associated protein was investigated as a predictor of clinical outcome in 100 rectal adenocarcinomas. In formalin-fixed tissues, a variety of silver-stained structures ranging from 0.5 to 7 microns are seen, the abundance of which bears no relation to prognosis, cell proliferation, or ploidy. Evidence is presented that the silver-stained structures are the result of coalescence of smaller particles caused by formalin fixation, and that assessment of NOR activity is not reliable in routinely formalin-fixed archival tissues.
Adenocarcinoma↗
Effects of ethanol on plasma corticosterone and rectal temperature modification by U50488H and WIN 44441-3.
Endogenous opiates are believed to subserve various behaviors and physiological functions. We have examined the effect of U50488H (0-12 mg/kg), a kappa agonist, and WIN 44441-3 (0-4.0 mg/kg), a kappa antagonist, on ethanol (ET)-induced changes in rectal temperature and in plasma corticosterone (CS) levels in rats. The 12 mg/kg dose of U50488H produced marked hypothermia, the other doses either produced hyperthermia comparable to that seen in control animals, or had no effect. The 0.5 mg/kg of WIN44441-3 had a small hypothermic effect while the 4.0 mg/kg produced hyperthermia. U50488H potentiated and the low dose of WIN 44441-3 reversed the hypothermic effect of ethanol. By contrast, neither WIN 44441-3 nor U50488H pretreatments affected the ethanol-induced elevation in plasma CS. These results indicate that kappa agonists increase plasma CS concentration and affect thermoregulatory mechanisms. Furthermore, our data indicate a possible role of endogenous kappa opioids in the hypothermic effect of ethanol, but not in the elevation of plasma CS.
3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
Effects of ethanol in an open field apparatus: modification by U50488H and WIN 44441-3.
The effects of U50488H, a kappa agonist, and WIN 44441-3, a kappa antagonist, and their modification of the effects of ethanol, on the behavior of rats in a modified open field apparatus, was examined. Crossover activity was increased by U50488H. Headpoke activity was decreased by WIN 44441-3 and increased by U50488H. Rearing activity was increased by WIN 44441-3 but was not affected by U50488H. The effect of both drugs was dose related, with the largest doses having no effect. Ethanol (0.5 g/kg) stimulated crossover activity while it depressed rearing, headpoke and corner activities; except for crossover activity the 2.0 g/kg dose of ethanol depressed these activities. Pretreatment with WIN 44441-3 (0.5 mg/kg) potentiated the stimulant effect of ethanol on crossover activity and partially reversed the depressant effect of ethanol on rearing and headpoke activities. U50488H potentiated the ethanol-induced depression of headpoke and reversed the depression of corner activity. Pretreatment with U50488H had no effect on ethanol's action on crossover and rearing behaviors. Our results indicate that kappa opiate receptors may mediate some behaviors exhibited by rats in a modified open field apparatus. Activation of these receptors increases locomotor and headpoke activity but had no effect on rearing activity. Furthermore, the 0.5 g/kg dose of ethanol has differential effects on different measures of open field behavior, while the 2.0 g/kg dose was largely depressant. Our data suggest that some of these effects of ethanol may be mediated via kappa opioid receptors.
3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
Alteration of the effects of caffeine by prenatal stress.
We examined the effect of prenatal stress exposure on sensitivity to caffeine using behavioral and physiological measures. Pregnant rats were handled 5 minutes daily from the 14th to 21st day of gestation. Male offspring were tested when 60 days of age in a modified open field apparatus 30 and 90 minutes after injection with caffeine (0, 10, 30 mg/kg). Caffeine increased crossover frequency and duration at the 10 mg/kg dose. Rearing frequency and duration were increased by the 10 mg/kg dose while the 30 mg/kg dose was ineffective. Gnawing was increased by caffeine, especially 90 minutes postinjection. Headpoke activity was decreased by caffeine treatment. Caffeine had no effect on defecation and urination. Gnawing activity was increased by caffeine in prenatally nonstressed animals, but was depressed in prenatally stressed animals. Prenatal stress increased sensitivity to caffeine on corner activity and rearing. The other measures were not affected differentially by prenatal stress exposure. Rectal temperature was depressed 0.75 degrees C in both prenatally stressed and nonstressed animals, by the 30 mg/kg dose of caffeine. Thus, our results indicate that prenatal stress affects sensitivity to caffeine in the adult offspring. However, the long-term effects of prenatal stress exposure are dependent on the measures employed.
Animals↗
The c-myc oncogene is regulated independently of differentiation in myeloid cell lines.
Human myeloid leukaemia (U-937 and HL-60) cells when incubated at low cell densities with human recombinant gamma-interferon underwent functional maturation without any loss of proliferative potential relative to uninduced cells. In addition, the proportion of cells in S,G2/M and levels of c-myc oncogene (mRNA and protein) were maintained at the same level as those of untreated control cells. However, cells grown under similar conditions but with retinoic acid matured to the same extent but became growth inhibited with concomitant reductions in the proportion of cells in S,G2/M and levels of c-myc mRNA and protein. These studies indicate firstly that c-myc levels are regulated independently from differentiation in myeloid (non lymphoid) cells, secondly that gamma-interferon can induce differentiation without growth arrest under conditions of low cell density and thirdly emphasise the close association of c-myc expression with proliferative capacity.
Cell Cycle↗
Trends in blood pressure, osmolality and electrolytes after subarachnoid hemorrhage from aneurysms.
Daily trends in blood pressure, osmolality and electrolytes were analyzed in a series of 173 operated aneurysm cases who had subarachnoid hemorrhage (SAH) and were admitted within 4 days of the ictus. High blood pressure was associated with a greater risk of mortality and the development of clinically significant vasospasm (VSP). High osmolality shortly after admission was related to mortality but not VSP. Changes in sodium and potassium had no obvious relationship to mortality or VSP.
Adolescent↗
Daily trends in white blood cell count and temperature after subarachnoid hemorrhage from aneurysm.
A retrospective analysis of the cases of 173 patients operated on for aneurysms and admitted to a neurosurgical service early after subarachnoid hemorrhage was conducted with respect to white blood cell (WBC) count and highest daily temperature. Daily trends for the development of clinically significant vasospasm (VSP) as well as mortality during the hospitalization were analyzed. An admission WBC count greater than 15 x 10(9)/l was associated with 55% mortality as opposed to 25% mortality for those with a lower WBC count. The mortality of those with a temperature greater than 37.5 degrees C on Day 0 was 60%, compared with 35% for those with a lower temperature. A WBC count greater than 15 x 10(9)/l on Day 0 was associated with a VSP rate of 40%; a lower WBC count was associated with a VSP rate of 30% Day 0 temperatures greater than 37.5 degrees C were associated with a VSP rate of 40%, while patients with lower temperature had a VSP rate of 30%. By Day 6, the patients with temperatures greater than 37.5 degrees C had a VSP rate of 60%, double that of the VSP rate of those with temperatures less than 37.5 degrees C. WBC count was apparently more closely linked to the chance of dying than the chance of developing VSP. The development of fever after a few days is related to both increased mortality and increased chance of developing VSP.
Adolescent↗
A case of two inversion (10) recombinants in a family.
A family is described in which the mother's four pregnancies resulted in one spontaneous abortion, one healthy boy, and a male and female sib with developmental delay and multiple minor dysmorphic features. Chromosome analysis showed a large pericentric inversion of chromosome 10, involving the region between bands p15.1 and q25.2, in the father and the healthy son: 46,XY,inv(10) (p15.1q25.2), and an unbalanced karyotype in the two affected sibs: rec(10),dup p,inv(10) (p15.1q25.2). The unbalanced chromosome has been produced by meiotic recombination between the inversion chromosome and its normal homologue. The two affected sibs have partial duplication of 10p and partial deficiency of 10q, and share a large number of clinical features, several of which have previously been described in both of these chromosome imbalances. We believe this to be the largest pericentric inversion of chromosome 10 reported to have produced recombinant offspring.
Abnormalities, Multiple↗
Look after yourself--useful exercise.
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Aged↗
Dihydrocodeine--a reversible cause of renal failure?
Two patients who developed severe narcosis and acute renal failure following therapeutic doses of dihydrocodeine are reported. The administration of naloxone produced an increase in respiratory minute volume and an improved level of consciousness. In addition, there was evidence of reversal of their renal failure with an increased urine output and creatinine clearance during the period of naloxone administration. Although the antidiuretic effect of opioids is well documented, opioids have not previously been incriminated in the aetiology of renal failure. The possible mechanism for this is discussed and the risks associated with the administration of dihydrocodeine to patients with renal failure or the elderly are emphasized.
Acute Kidney Injury↗
Empirical therapy for the management of acute proctitis in homosexual men.
An effective empirical treatment regimen would provide a more rapid and less expensive approach to the management of homosexual men with acute proctitis. We conducted a randomized trial in 129 homosexual men who presented with acute proctitis, comparing treatment with an empirical regimen (4.8 million U of aqueous penicillin G procaine intramuscularly and 1.0 g of probenecid orally, followed by 100 mg of oral doxycycline twice daily for seven days) with specific therapy for each infection as it was recognized. Therapy with the empirical regimen resulted in more rapid resolution of the symptoms of proctitis, the objective signs of proctitis, and the infecting microorganisms. However, nearly one fourth of the patients, primarily those with unrecognized herpes simplex virus proctitis, did not respond to empirical therapy. We recommend empirical therapy coupled with appropriate pretreatment diagnostic testing for the initial management of acute proctitis in homosexual men with no clinical evidence of acquired immunodeficiency syndrome or AIDS-related complex.
Adolescent↗
Regional distribution of pre- and postsynaptic glutamatergic function in Alzheimer's disease.
Ca2+/Cl- -independent L-[3H]glutamate- and sodium-dependent D-[3H]aspartate binding assays were used to assess the integrity of N-methyl-D-aspartate (NMDA) receptors and glutamate uptake sites in a number of areas from control and Alzheimer's diseased brain. NMDA receptor densities were unchanged in all areas tested. In contrast, significant reductions in the number of glutamate terminals were seen in the hippocampus of the Alzheimer's samples. A smaller reduction was seen in the caudate nucleus but this failed to reach significance. No such reductions were seen in either the frontal or parietal cortices.
Aged↗
Presynaptic and postsynaptic glutamatergic function in Alzheimer's disease.
Sodium dependent D-aspartate and Ca2+/Cl-independent L-glutamate binding assays were used to assess the integrity of glutamate uptake sites and postsynaptic NMDA receptor levels in control and Alzheimer's disease temporal cortex. The number of glutamate uptake sites was significantly and substantially reduced in accordance with previous findings. However, NMDA receptor levels were unchanged. This finding suggests that glutamatergic presynaptic elements are severely reduced in Alzheimer's disease, whilst postsynaptic elements remain intact.
Aged↗
Factors modifying the effect of diazepam on plasma corticosterone levels in rats.
We have examined factors that alter the effect of diazepam (DZ) on plasma corticosterone (CS) in rats. DZ had a biphasic effect on plasma CS levels: CS decreased with doses below 5 mg/kg and increased with higher doses. Peak response occurred 90 minutes post injection in both sexes. Plasma DZ levels were significantly higher in females than in males and peak at 10 and 30 minutes post injection in males and females, respectively. There was also a sex difference in the pattern of DZ metabolites. An acute stressor (30 minutes of immobilization) did not affect plasma CS levels in rats injected with a 5 mg/kg dose of DZ. Prenatally stressed animals did not differ in basal CS levels or in their response to 5 mg/kg of DZ compared to prenatally non-stressed animals. These two groups of animals also did not differ in plasma levels of DZ or of its metabolites. By contrast, the 5 mg/kg dose of DZ had no effect on plasma testosterone levels in control animals, but increased it in prenatally stressed animals. Furthermore, compared to non-stressed controls, prenatally stressed animals had lower baseline plasma testosterone levels. These results indicate that the effect of DZ on plasma CS is influenced by endogenous as well as exogenous factors and that these effects vary with the particular biochemical parameter under examination.
Animals↗
Dioxin: are we safer now than before.
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Carcinogens↗
Subrenal capsule assay (SRCA) in human tumors.
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Humans↗