The effect of tubocurarine on indirectly elicited train-of-four muscle response and respiratory measurements in humans

The effect of tubocurarine on the respiratory function of conscious, non-medicated volunteers was correlated with the degree of neuromuscular blockade measured with the train-of-four technique (the evoked response of the adductor pollicis brevis muscle to trains of four supramaximal ulnar nerve stimuli at 2 Hz, repeated once every 10 sec). Respiratory frequency, tidal volume, vital capacity, inspiratory force and peak expiratory flow rate were measured, (a) before administration of tubocurarine, (b) when the ratio of the amplitude of the fourth response to the amplitude of the first response of the train-of-four reached 60%, and (c) during recovery of the ratio until the control (100%) value was reached. Respiratory frequency, tidal volume and peak expiratory flow rate were not altered. Vital capacity and inspiratory force were both reduced significantly at the 60% level and the former also at the 70% level when compared with the control. The magnitude of change in all variables is of minor clinical importance, however, since the lowest measured values are well above acceptable minimum limits required for adequate respiratory function.

Cyperus rotundus L.: Traditional uses, phytochemistry, and pharmacological activities

ETHNO-PHARMACOLOGICAL RELEVANCE

Cyperus rotundus L. (Cyperaceae) is a medicinal herb traditionally used to treat various clinical conditions at home such as diarrhea, diabetes, pyresis, inflammation, malaria, and stomach and bowel disorders. Currently, it is one of the most widespread, problematic, and economically damaging agronomic weeds, growing wildly in various tropical and subtropical regions of the world. The present paper summarizes the available information that will aid in future medicine preparation by identifying active ingredients and their mode of action for a specific therapeutic activity using the latest technologies.

MATERIAL AND METHOD

This review article is based on the information available on the phytochemical, toxicological, and pharmacological studies on and traditional uses of C. rotundus. The present paper covers the literature available particularly from 2000 to 2015 online (Google Scholar, PubMed, ScienceDirect, Scopus, SpringerLink, and Web of Science) and in books on phytochemistry, ethnopharmacology, and botany of this plant.

RESULTS

Phytochemical and pharmacological studies revealed the significance of C. rotundus as an antiandrogenic, antibacterial, anticancerous, anticonvulsant, antidiabetic, antidiarrheal, antigenotoxic, anti-inflammatory, antilipidemic, antimalarial, antimutagenic, antiobesity, antioxidant, anti-uropathogenic, hepatoprotective, cardioprotective, neuroprotective, and nootropic agent. This is the most investigated plant worldwide due to the higher concentration of active ingredients in the form of essential oils, phenolic acids, ascorbic acids, and flavonoids in the tuber and rhizomes. Unfortunately, this significant plant species has not been assessed under improved cultivation conditions with the aim of conservation in natural habitats and high quality.

CONCLUSION

Reports can be found on the ehtnobotanical use of C. rotundus in atherosclerosis, aging, apoptosis, cancer, cystitis, epilepsy, hirsutism, nociception, prostatitis, and genotoxicity disorders. The phytochemical and pharmacological activities of C. rotundus have supported its traditional as well as prospective uses as a valuable Ayurvedic plant. Previous researches focuses on the phytochemistry, biological properties and clinical application of rhizomes and tubers of C. rotundus. However, such studies on the other parts of this medicinally important plant are still quest to be investigate. Furthermore, future study should aim at confirming the clinical activities and safety of this plant before being used for the development of new therapeutic agent in human subjects.

Spontaneous recovery from nondepolarizing neuromuscular blockade: correlation between clinical and evoked responses

The effects of nondepolarizing muscle relaxants were allowed to wear off spontaneously in 10 ASA class III and IV patients following major surgery. Neuromuscular and respiratory function were followed by clinical testing and by evoked muscle responses using a train of 4 (TOF) supramaximal stimuli. At a TOF of 70 percent (range 62 to 78%), all patients sustained eye-opening, hand-grasp, and tongue-protrusion, while 9/10 sustained head-lift. Vital capacity (VC) averaged 17 ml/kg when the TOF reached 70 percent. The increase in VC correlated with the increase in TOF (r = 0.88). There was no correlation between inspiratory force (IF) and TOF, but all patients achieved an IF equal to or greater than -22 cm H2O at 70 percent. Thus, TOF correlates well with clinical signs of neuromuscular and respiratory recovery in this group of patients and complements earlier studies in healthy anesthetized patients and nonmedicated volunteers.

Clinical pharmacology of mivacurium chloride (BW B1090U) infusion: comparison with vecuronium and atracurium

Mivacurium chloride (BW B1090U) is a new, short-acting non-depolarizing neuromuscular blocking agent. It is a synthetic bis-benzylisoquinolinium diester, which is hydrolysed rapidly by plasma cholinesterase. This study compares mivacurium, atracurium and vecuronium by continuous i.v. infusion. The duration of mivacurium infusion ranged from 29.5 to 286 min. The steady state infusion rates necessary to maintain 95 (SEM 4)% twitch suppression were: mivacurium 8.3 (0.7) micrograms kg-1 min-1; atracurium 7.9 (0.4) micrograms kg-1 min-1; vecuronium 1.2 (0.3) micrograms kg-1 min-1. Following infusions of mivacurium, various recovery times (for example: 25-75%, 6.9 (0.3) min; 25-95%, 11.0 (0.4) min; 5-95% 14.5 (0.4) min) did not differ significantly from those following single bolus doses. Recovery times following cessation of mivacarium infusions were approximately 50% of those for equivalent durations of infusion of atracurium (10.9 (0.3) min for 25-75% recovery and 26.6 (0.4) min for 5-95% recovery). For vecuronium, corresponding recovery times were 13.8 (0.9) and 32.0 (1.2) min, respectively. Comparative recovery times for mivacurium were 40-50% of those for vecuronium. There was a significant correlation between the infusion rate of mivacurium required to maintain 95% twitch depression and the plasma cholinesterase activity of individual subjects.

Twitch, tetanus and train-of-four as indices of recovery from nondepolarizing neuromuscular blockade

This study was undertaken to compare the sensitivities of the train-of-four response (2 Hz for 2 s), the single twitch (0.15 Hz), and the tetanic response (50 Hz for 5 s) as indices of residual nondepolarizing block. Spontaneous or induced recovery of evoked thumb adduction in response to ulnar nerve stimulation was studied. One hundred and seven adult surgical patients were divided according to the relaxant used, into six groups. We found that when the single twitch recovered to control height, the train-of-four ratio was well below 1.0. This ratio was significantly lower during spontaneous recovery than following neostigmine antagonism of the block (P less than 0.01). The tetanic response was fully sustained when the train-of-four ratio was above 0.7. When the ratio was less than 0.7, variable degrees of fade of tetanus were evident. Analysis of variance indicated similar train-of-four ratios among the six groups at complete recovery of the single twitch irrespective of the relaxant technique used (P less than 0.1). It is concluded that a train-of-four ratio of 0.7 or higher reliably indicates the recovery of the single twitch to control height and a sustained response to tetanic stimulation at 50 Hz for 5 s. The clinical significance of this study is as follows: the train-of-four response provides the same indication of clinical recovery from nondepolarizing block as obtained from tetanic stimulation at a physiological frequency; and reliance on the recovery of the single twitch to control height as a criterion of spontaneous return to normal clinical neuromuscular function may be misleading.

The cardiovascular effects of mivacurium chloride (BW B1090U) in patients receiving nitrous oxide-opiate-barbiturate anesthesia

The dose-effect relationship of mivacurium chloride on arterial blood pressure, heart rate, and plasma histamine was determined in 97 consenting ASA physical status I-II patients receiving nitrous oxide-oxygen-opiate-barbiturate anesthesia. In the absence of surgical stimulation during steady state anesthetic conditions with controlled ventilation, average maximum change in tachograph-counted heart rate was 7% or less after 10-15-s injection of mivacurium at all doses from 0.03 to 0.30 mg/kg. Average peak change in mean arterial pressure measured via radial arterial catheter was 7% or less after all doses from 0.03 to 0.15 mg/kg. Transient (0.2-4.5 min) decreases in arterial blood pressure were noted after 10-15-s injection in some patients at 0.20, 0.25, and 0.30 mg/kg. When they occurred, these changes were usually accompanied by facial erythema lasting 2-5 min and were correlated with increases in plasma histamine level (P less than 0.001). Facial erythema, decrease in blood pressure, and elevation of histamine level were all accentuated by increasing the dose of mivacurium and by more rapid injection of the drug. For example, mean blood pressure decreased an average of 13% after injection of mivacurium 0.25 mg/kg over 10-15 s. In contrast, during administration over 30 and 60 s of this dose, arterial pressure decreased 7.6 and 1.5%, respectively (P less than 0.001, 10-15 s vs. 60-s injection). Average peak histamine level, which increased to 132% of control after administration of 0.25 mg/kg over 10-15 s, did not change after injection over 60 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Atracurium: clinical strategies for preventing histamine release and attenuating the haemodynamic response

This study was designed to determine the effects of a rapid bolus dose of atracurium 0.6 mg kg-1 on arterial pressure, heart rate and plasma histamine concentration (n = 9), and to compare these values with those obtained by (a) giving the same dose of atracurium slowly (over 75 s) (n = 9), or (b) pre-treating with H1- and H2- antagonists (n = 9). The rapid (5-s) bolus dose of atracurium i.v. resulted in a significant increase in plasma histamine concentration (P less than 0.05) and was associated with a decrease in mean arterial pressure and an increase in heart rate. Administering the same dose of atracurium slowly (over 75 s) prevented the increase in plasma histamine concentration, and abolished the subsequent haemodynamic response. Pretreatment with cimetidine 4 mg kg-1 i.v. and chlorpheniramine 0.1 mg kg-1 i.v. abolished the haemodynamic response despite a moderate increase in histamine concentration (0.1 greater than P greater than 0.05).

Stimulus frequency and dose-respone curve to d-tubocurarine in man

The relationship of the frequency of motor-nerve stimulation to the dose--response to d-tubocurarine was studied in 45 adult patients during nitrous oxide--oxygen--morphine--thiopental anesthesia. One of five stimulus frequencies, 0.1, 0.15, 0.25, 0.5, and 1.0 Hz, was employed in each of five groups of nine patients. Cumulative dose-response curves for inhibition of evoked thumb adduction were constructed at each frequency on log probit scales and the ED50 and ED95 values were determined. The apparent potencies of d-tubocurarine at 0.5 and1.0 Hz were significantly different from that at 0.1 Hz; for example, at 0.1 Hz the ED50 and ED95 were 0.25 and 0.52 mg/kg, respectively. The corresponding values at 1.0 Hz were 0.07 and 0.15 mg/kg, respectively, or approximately 3.5 times less. The durations of recoveries of the twitch from 5--25 per cent of control at 1.0 and 0.5 Hz were 13 +/- 2 min (mean +/- SE) and 20 +/- 2 min, respectively. These durations were significantly different from that at 0.1 Hz (30 +/- 2 min). These results emphasize the importance of defining the stimulus frequency for meaningful interpretation of the dose--response relationships for nondepolarizing relaxants in man. Slow stimulus rates (0.1--0.15 Hz) are most useful clinically, since all levels of clinical relaxation can be achieved at these rates without abolishing the evoked twitch response.

Clinical pharmacology of atracurium given in high dose

The safety and efficacy of atracurium 0.8 mg kg-1 was determined in healthy patients with particular attention to the speed of onset of blockade, and to changes in haemodynamic variables. Atracurium 0.8 mg kg-1 had a shorter onset time than atracurium 0.5 mg kg-1, and satisfactory intubating conditions were achieved earlier. "Priming" produced no significant improvement in onset time or intubating conditions. Onset times were significantly shorter with nitrous oxide-opioid anaesthesia than following thiopentone alone. Although a 0.8-mg kg-1 bolus resulted in a significant reduction in mean arterial pressure to 75% of control and was associated with a significant increase in plasma histamine concentrations, this response could be prevented by injecting the drug over 75 s. "Priming" or a 30-s injection produced no haemodynamic protection. The protection achieved by pretreatment with anti-histamines was incomplete: mean arterial pressure decreased to 83% of control.

A comparison of the intubation conditions between mivacurium and rocuronium during balanced anesthesia

BACKGROUND

Comparisons of the intubation conditions with mivacurium and rocuronium from previous reports are confounded by the use of varied induction regimens. The authors compared intubation conditions of mivacurium, rocuronium, and a placebo at 90 s and their recovery profiles during anesthesia with nitrous oxide, oxygen, and propofol.

METHODS

After induction with midazolam, fentanyl, and propofol in a randomized blinded study, 100 patients received one of the following treatments: 0.25 mg/kg mivacurium in divided doses (0.15 mg/kg followed by 0.1 mg/kg 30 s later); 0.45, 0.6, 0.9, or 1.2 mg/kg rocuronium; or placebo. Evoked thumb adduction was measured throughout. Intubation was attempted 90 s after the initial dose of mivacurium and other treatment doses by a "blinded" physician. Intubating conditions were graded as excellent, good, poor, or not possible. Spontaneous recovery was studied until a 25% initial twitch height was reached. Mean arterial blood pressure and heart rate changes between groups were determined before induction through 6 min after administration of the study drugs.

RESULTS

There were no important changes or intergroup differences in mean arterial blood pressure and heart rate. Intubation conditions were good or excellent for both mivacurium and rocuronium at the 0.9 mg/kg dose (93%) and at the 1.2 mg/kg dose (100%). Rocuronium at the 0.6 mg/kg dose was excellent in 27% of patients, whereas rocuronium at the 0.45 mg/kg dose had the least number of excellent conditions and the most poor or not possible assessments. Patients given placebo could not be intubated. Times to maximum blockade for 0.9 and 1.2 mg/kg rocuronium were the shortest. The times to 25% recovery for 0.6 mg/kg rocuronium (mean +/- SD = 27 +/- 8.6 min), 0.9 mg/kg (43.1 +/- 10.8), and 1.2 mg/kg (62.3 +/- 17.4 min) were significantly longer than were those for mivacurium (17.4 +/- 6.2 min).

CONCLUSIONS

Mivacurium in a 0.25 mg/kg divided dose and rocuronium at 0.9 mg/kg and 1.2 mg/kg provide good or excellent intubation conditions at 90 s in most patients. Rocuronium was faster in onset at the higher doses (0.9 and 1.2 mg/kg) but had more prolonged recovery times to 25% single twitch height.

Pharmacokinetics and pharmacodynamics of doxacurium in young and elderly patients during isoflurane anesthesia

Preliminary disposition studies of the investigational, long-acting muscle relaxant doxacurium chloride (Nuromax) have demonstrated dual elimination by renal and hepatobiliary pathways, as well as slow hydrolysis by plasma cholinesterase. The present study compares the kinetics and dynamics of doxacurium in eight ASA physical status I or II elderly patients (67-72 yr of age) and eight ASA I or II young patients (22-49 yr of age). After institutionally approved written informed consent, kinetic and dynamic measurements were made after a 25-micrograms/kg bolus injection of doxacurium during 1.25 MAC nitrous oxide/oxygen/isoflurane anesthesia. Maximum twitch depression was similar in older patients (96.4% +/- 1.3%) to that in the young patients (96.6% +/- 1.8%). The time to achieve this level of block was significantly longer in the elderly than in the young (11.2 +/- 1.1 min versus 7.7 +/- 1.0 min, respectively). Recovery times to twitch heights of 5% and 25% of control tended to be prolonged and were more variable in the elderly (82.6 +/- 17.2 and 97.1 +/- 20.1 min, respectively) than in the young (54.8 +/- 9 and 67.5 +/- 8.2 min, respectively). Elimination half-life (96 +/- 20 min) and clearance (2.47 +/- 0.69 mL.kg-1.min-1) in the elderly patients were not statistically different from values found in the younger group. Volume of distribution at steady state in the elderly (220 +/- 80.2 mL/kg) was significantly larger than in the young (150 +/- 40.0 mL/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

The parathyroid in chronic renal failure-- a light and electron microscopical study

The parathyroids from ten consecutive cases of chronic renal failure coming to operation in a period of seven years were studied by light and electron microscopy. The clinical and biochemical data as well as the levels of immunoreactive parathormone (iPTH) were reviewed. For the sake of comparison adenomata from two cases of primary hyperparathyroidism were studied. In the cases of chronic ;renal failure there were six cases of tertiary hyperparathyroidism with adenoma formation, surrounded by dense fibrous tissue and compression of adjacent parathyroid cell amidst a background of hyperplasia. Two cases showed secondary parathyroid hyperplasia and the remaining two cases were adenomata which clinically affected only one gland. Neither the biochemical data nor levels of iPTH allowed the cases with secondary hyperplasia to be separated from those with tertiary hyperparathyroidism. Similarly electron microscopy showed no distinct differences between these two groups of adenomata from cases of primary hyperparathyroidism. The diagnosis of tertiary hyperparathyroidism is made on a combination of clinical, biochemical and histological features, the histological features being most important. It is concluded that tertiary hyperparathyroidism is part of a histological spectrum in response to chronic renal failure and autonomous glands are related to the mass of parathyroid tissue present.

Biology and management of two important Conyza weeds: a global review

Weed management is one of the prime concerns for sustainable crop production. Conyza bonariensis and Conyza canadensis are two of the most problematic, noxious, invasive and widespread weeds in modern-day agriculture. The biology, ecology and interference of C. bonariensis and C. canadensis have been reviewed here to highlight pragmatic management options. Both these species share a unique set of biological features, which enables them to invade and adapt a wide range of environmental conditions. Distinct reproductive biology and an efficient seed dispersal mechanism help these species to spread rapidly. Ability to interfere strongly and to host crop pests makes these two species worst weeds of cropping systems. These weed species cause 28-68 % yield loss in important field crops such as soybean and cotton every year. These weeds are more prevalent in no-till systems and, thus, becoming a major issue in conservation agriculture. Cultural practices such as crop rotations, seed rate manipulation, mulching, inter-row tillage and narrow row spacing may provide an effective control of these species. However, such methods are not feasible and applicable under all types of conditions. Different herbicides also provide a varying degree of control depending on crop, agronomic practices, herbicide dose, application time and season. However, both these species have evolved resistance against multiple herbicides, including glyphosate and paraquat. The use of alternative herbicides and integrated management strategies may provide better control of herbicide-resistant C. bonariensis and C. canadensis. Management plans based on the eco-biological interactions of these species may prove sustainable in the future.

Myofibroblastoma of breast: evidence favoring smooth-muscle rather than myofibroblastic differentiation

A histopathological study of two cases of the tumor known in the literature as myofibroblastoma of the breast is presented. The tumors occurred in Caucasian males aged 57 and 62 years. Histologically, these were moderately cellular, lobulated spindle-cell lesions, each with a reasonably well-delineated edge with surrounding fatty connective tissue. No breast ducts or lobules were present. Tumor cell nuclei were bland, with small nucleoli and some nuclear grooving. Nuclear atypia and mitoses were absent. Immunostaining revealed positivity for a-smooth-muscle actin, desmin, and CD34. Tumor cells contained rough endoplasmic reticulum, bundles of myofilaments with focal densities, intermediate filaments, attachment plaques alternating with plasmalemmal caveolae, and focal lamina. Ultrastructural findings pointed to true smooth-muscle differentiation, and the cell-surface in particular lacked surface features of myofibroblasts (fibronectin fibrils [microtendons] and fibronexus junctions). These and published data suggest that at least some of the lesions referred to in the literature as myofibroblastoma may not be myofibroblastic and may be better designated as myogenic stromal tumors or as variants of leiomyoma.

Cytokinin Production by Azospirillum brasilense Contributes to Increase in Growth, Yield, Antioxidant, and Physiological Systems of Wheat (Triticum aestivum L.)

Plant growth-promoting rhizobacteria are known to associate with several cereal crops. The rhizobacterium exerts its function by synthesizing diverse arrays of phytohormones, such as cytokinin (Ck). However, it is difficult to determine the plant growth promotion when a bacterium produces many different kinds of phytohormones. Therefore, to assess the involvement of Ck in growth promotion and activation of antioxidant and physiological systems, we set up this experiment. Wheat seeds (Triticum aestivum L.) were inoculated with Azospirillum brasilense RA−17 (which produces zeatin type Ck) and RA−18 (which failed to produce Ck). Results showed that seed inoculation with RA−17 significantly improved growth and yield-related parameters compared with RA−18. The activity of enzymes, proline contents, and endogenous hormonal levels in wheat kernels were improved considerably with RA−17 than with RA−18. Strain RA−17 enhanced grain assimilation more than strain RA−18 resulting in a higher crop yield. These results suggest that microbial Ck production may be necessary for stimulating plant growth promotion and activating antioxidant and physiological systems in wheat.