Is phenytoin contraindicated in patients receiving cranial irradiation ?

Three recent publications have reported the development of erythema multiforme and Stevens-Johnson syndrome in patients receiving cranial irradiation and sodium phenytoin. Some authors have recommended that patients receiving whole brain radiation therapy and who have had seizures should not be prescribed phenytoin but an alternative anticonvulsant. This article reviews the current literature pertaining to the development of this potentially lethal complication in patients receiving whole brain radiation and phenytoin, with reference to the single recorded case of Stevens-Johnson syndrome in a patient receiving cranial irradiation and phenytoin in Auckland, New Zealand. While the clinical picture in the 16 patients reported in the literature and the current case report differed from the classical form of erythema multiforme, a similar pattern of presentation and outcome appeared in all patients reviewed, suggesting that the combination of phenytoin, cranial irradiation and the gradual reduction of concomitant steroids seem to lead to the development of erythema multiforme and/or Stevens-Johnson syndrome. The data presented, although sparse, suggest that phenytoin should not be prescribed in patients receiving cranial irradiation.     

Review of 59 patients with hypergonadotrophic amenorrhoea

Fifty-nine patients presented with elevated concentrations of gonadotrophins and secondary amenorrhoea before the age of 35 years. Fifty-three underwent laparoscopic examination and primordial follicles were observed in 16. Two others had follicles as they later became pregnant and a third showed biochemical evidence of spontaneous ovulation. There were streak ovaries in 12, two with follicles and three others with chromosomal abnormalities, two being 47XXX and one XO/XX. Two other patients had only one ovary each but no follicles. Chromosomal abnormalities were detected in two further patients one being XO/XX and the other a recombinant. Six patients became pregnant, two of them twice, resulting in four term deliveries and four spontaneous abortions. Three other patients showed biochemical evidence of ovulation; one spontaneously, one after oestrogen therapy and the third after treatment with gonadotrophin releasing hormone analogue.     

氨溴索治疗小儿毛细支气管炎77例

1临床资料2002-01／2004-02收治临床症状典型且无并发症毛细支气管炎患儿116例，发病年龄3-24(平均8．4)mo，男61例，女55例，按就诊时间顺序分为氨溴索雾化吸入组(观察组)、氨溴索静脉点滴组(对照Ⅰ组)和常规治疗组(对照Ⅱ组)，分别为38，39，39例．常规治疗组给予头孢噻肟钠50mg／kg，2／d及穿琥宁80-120mg／d分别静脉滴注及对症治疗(如吸氧、镇静、退热等处理)；观察组在常规治疗的基础上加用氨溴索4mg加生理盐水10mL超声雾化吸入10～15min，2／d；     

Airway and body surface sensors for triggering in neonatal ventilation

Failure of neonatal patient triggered ventilation may reflect a delay in delivery of flow relative to the inspiratory effort of the infant. Transmission of diaphragmatic contraction to the sensor site (patient delay) and further transmission to and within the sensing device (device delay) both contribute to the delay in triggering. Patient and device delays were studied for different sensing systems in 36 infants, 24 of whom were intubated. Device delay was long (<40 ms) with a conventional apnoea monitor compared with sensors placed at the airway opening (2 ms), the inspiratory (12 ms) and expiratory (3 ms) pressure transducers of the ventilator, the Graseby capsule (8 ms), strain gauges (3 ms) and oesophageal pressure (6 ms). In near normal infants, the sum of patient and device delays for the latter sensors was less than 20 ms and a minor component of the total delay. However, in severe lung disease the total delay may be more than 100ms even for airway sensors.     

The 'anomalous' absorption of labelled and unlabelled vitamin C in man

Previous studies of vitamin C absorption in man using stable isotope probes have given results which cannot easily be reconciled with those obtained using non-isotope measurement. In order to investigate some of the apparent paradoxes we have conducted a study using two consecutive doses of vitamin C, one labelled and one unlabelled, given 90 min apart. Compatibility of the experimental results with two feasible models was investigated. In Model 1, ingested vitamin C enters a pre-existing pool before absorption, which occurs only when a threshold is exceeded; in Model 2, ingested vitamin C is exchanged with a pre-existing flux before absorption. The key difference between these two models lies in the predicted profile of labelled material in plasma. Model 1 predicts that the second unlabelled dose will produce a secondary release of labelled vitamin C which will not be observed on the basis of Model 2. In all subjects Model 1 failed to predict the observed plasma concentration profiles for labelled and unlabelled vitamin C, but Model 2 fitted the experimental observations. We speculate on possible physiological explanations for this behaviour, but from the limited information available cannot unequivocally confirm the model structure by identifying the source of the supposed flux.     

13C- and 2H-labelled glucose compared for minimal model estimates of glucose metabolism in man

In the present study, we have investigated the use of 1-[(13)C]glucose and GC/combustion/isotope-ratio MS as an alternative to 6,6-[(2)H(2)]glucose and GC/MS in the determination of parameters of glucose metabolism using the IVGTT (intravenous glucose tolerance test) interpreted by labelled (hot) minimal models. The study has been done in four populations, normoglycaemics (subdivided into lean and obese individuals), subjects with impaired glucose tolerance and those with diabetes mellitus. Although the use of carbon label may in some circumstances be compromised by substrate recycling, our hypothesis was that this would not be an issue under the condition of suppression of hepatic glucose production during the short timescale of an IVGTT. In all four groups, we found that the methodology employing the carbon label gave equivalent results to those obtained using the conventional deuterated material, but the sensitivity of the measurement technique in the new approach was sufficient to allow an approx. 15-fold reduction in the quantity of isotope administered. In addition to the clear cost advantages, this represents a significant scientific advance in that true tracer status is more nearly attained in these measurements with near-physiological tracee loads.     

Acquired pendular nystagmus: its characteristics, localising value and pathophysiology

Investigations were made of 16 patients with acquired pendular nystagmus and a further 32 cases reported in the literature were reviewed. Amongst our own patients two thirds had multiple sclerosis, almost one third a cerebrovascular accident or angioma and two had optic atrophy with squint. The nystagmus took forms which could be monocular or binocular, conjugate or disconjugate and could involve movements about single or multiple axes. Spectral analysis was used to characterise the amplitude and frequency of the movements and to estimate the degree of relationship (coherence) between movements of the two eyes or between movements of one eye about several axes. The oscillations ranged in frequency from 2·5 Hz to 6 Hz, with typical amplitudes between 3° and 5°. In a given patient all oscillations, regardless of plane, were highly synchronised. Somatic tremors of the upper limb, face and palate associated with the nystagmus were often at similar frequencies to the eye movement. The other ocular signs common to all our patients were the presence of squint with failure of convergence. Most patients also had skew deviation or internuclear ophthalmoplegia or both. The major oculomotor systems, that is, saccades, pursuit, optokinetic and vestibulo-ocular reflexes could be intact. It is inferred that the mechanism responsible for the pendular nystagmus lies at a level which is close to the oculomotor nuclei so that it can have monocular effects but is not part of the primary motor pathways. It is possible that this mechanism normally subserves maintenance of conjugate movement and posture of the eyes. The periodicity of the nystagmus is likely to arise from instability in a certain type(s) of neurone, for the associated somatic tremors have similar characteristics and yet involve very different neuronal muscular circuitry. Prognosis for cessation of the nystagmus is poor. In five patients with multiple sclerosis it was suppressed by intravenous hyoscine with, however, unacceptable subsequent side effects.     

Dietary fat, body weight, and cancer: contributions of studies in rodents to understanding these cancer risk factors in humans

Understanding diet and energy balance as risk factors for breast, colon, and other cancers requires information on the contribution of each factor and of interactions among factors to cancer risk. Rodent models for breast cancer provide extensive data on effects of dietary fat and calories, energy balance, body weight gain, and physical activity on tumor development. Analyses of the combined data from many studies have shown clearly that quality and quantity of dietary fat and energy balance contribute independently to increased mammary gland tumorigenesis. These findings were seen in female rats fed diets high in fat (35-40% of calories) compared to rats fed control diets, with approximately 10% of calories as fat (Fay and Freedman, 1997, Breast Cancer Res. Treat. 46, 215-223). The methods used permit comparison of experimental and epidemiological data, and they may be useful in extrapolating between species and developing public health recommendations. In addition to the contributions of lifetime-diet composition, intake, energy balance, and physical activity to cancer risk, there are questions about the timing and duration of alterations in these factors and about the "dose-response" characteristics of cancer risk to the factors. Endocrine mechanisms may be significant in mammary gland tumor risk, but experimental and epidemiological data indicate that cancers at other sites, such as colon and liver, also are influenced by the factors listed. Other diet and lifestyle factors that influence energy, or specifically fat, metabolism may also affect risk for cancers that are promoted by increased intake of fat and calories. Studies of separate and interactive effects of dietary fat, black tea, weight gain, and mammary gland tumorigenesis (Rogers, et al, 1998, Carcinogenesis 19, 1269-1273) have been analyzed. Using adjustment of carcinogenesis endpoints for body weight, tumor burden, and latency, they were found to be related to weight gain within treatment groups in 2 of 3 experiments.