Low-Dose Doxapram Therapy in Premature Infants and Its CSF and Serum Concentrations

ABSTRACT. The efficacy of low-dose doxapram therapy (0.2 mg/kg/h) in combination with methylxanthines was evaluated in 20 premature infants with idiopathic apnea unresponsive to methylxanthines alone, and in 13 premature infants with secondary apnea. The serum concentrations of doxapram and, in some infants, the simultaneous cerebrospinal fluid and serum concentrations were measured, and the correlation between cerebrospinal fluid and serum concentrations in the postnatal period was determined. The following results were obtained: 1) In idiopathic apnea of prematurity, low-dose doxapram therapy was as effective as a dose of 1.0-2.5 mg/kg/h and the side effects were few, mild, and reversible. 2) In premature infants over seven days of age, serum concentrations of doxapram were almost stable but were significantly lower than in infants within the first six days of life. 3) The ratio of the cerebrospinal fluid to serum doxapram concentration was 0.48 ± 0.13 (mean ± SD). There was a good correlation between cerebrospinal fluid and serum concentrations ( r = 0.933, p < 0.001). The initial doxapram dose can be set as low as 0.2 mg/kg/h in very young premature infants with idiopathic apnea of prematurity unresponsive to methylxanthines.     

Prenatal lead exposure in relation to gestational age and birth weight: A review of epidemiologic studies

Although the adverse effect on pregnancy outcomes at high levels of lead exposure in the workplace has been recognized for years, there is uncertainty regarding the impact of exposure at the lower community exposure levels commonly encountered today. This review summarizes the epidemiologic literature and discusses pertinent methodologic issues and possible sources of interstudy variation. The authors conclude that prenatal lead exposure is unlikely to increase the risk of premature membrane rupture but does appear to increase the risk of preterm delivery. Whether prenatal lead exposure decreases gestational age in terms of infants is unclear. Prenatal lead exposure also appears to be associated with reduced birth weight, but results vary in relation to study design and degree of control for confounding. Adjustment for gestational age, a possible confounder of the birth weight-lead exposure association, did not yield clearer results.     

原发性肾小球疾病患者T淋巴细胞亚群变化的初探

本文应用磁性磷酸酶－抗碱性磷酸酶桥联酶标技术（APAAP），对27例原发性肾小球疾病患者外周血T淋巴细胞亚群进行观察。结果表明：本组病例表现为CD细胞升高，CD细胞减少，和CD／CD比值增加。提示原发性肾小球疾病可导致细胞免疫功能改变，T淋巴细胞亚群的变化，是肾组织损害的一个间接证据，可作为临床诊断一个有价值的参考指标。     

The effects of acute exercise on colonie motility

Abstract Changes in colonic motor activity during aerobic exercise were investigated in ten regularly exercising volunteers (five males and five females) aged 27–70 years. Motility was recorded with a catheter containing three solid-state pressure transducers spaced 5 cm apart. The motility catheter was advanced 40–50 cm from the anal verge by flexible sigmoidoscope without anesthesia at least 60 min prior to testing. Manometric recordings were made from the colon during a 1-h pre-exercise rest period, 1 h of jogging at 70–80% maximum heart rate, and 1-h post-exercise rest period. The dominant frequency of contractile activity in the colon shifted from 1–4 cpm during rest, to 4–9 cpm with the onset of exercise. Activity also shifted from sporadic, isolated contractions to regular, propagated contractions in six of ten subjects, five of whom reported a history of runner's diarrhoea. The dominant frequency returned to 1–4 cpm during the post-exercise period. These changes in distal colonie motility may account for the diarrhoea which some subjects experience during intense, acute exercise.     

Canine Latissimus Dorsi Muscle: An Apparatus for Isometric Force Measurements

Abstract: This paper describes a device used to measure the isometric forces generated during electrical stimulation of the canine latissimus dorsi muscle in vivo with a preserved neurovascular supply. This device uses 2 strain gauge force sensors linked to a movable alignment frame to which the muscle is attached. The muscle length is controlled by the application of known weights to the system. The device has a frequency of response of 17.5 Hz and compliance of -0.1 mm N^-1, and its experimental performance was tested in the anesthetized mongrel dog.     

Left ventricular growth in a patient with critical coarctation of the aorta and hypoplastic left ventricle

An infant is presented who at birth met criteria consistent with hypoplastic left heart syndrome. He was followed clinically and by 11 weeks of age demonstrated substantial growth of the left ventricle. He underwent successful repair of coarctation of the aorta and continues to do well with moderate aortic stenosis. The difficulties of predicting left ventricular growth and function are discussed, and management options are reviewed.     

Chromatic pattern-reversal electroretinograms (ChPERGs) are spared in multiple system atrophy compared with Parkinson’s disease

Abstract Idiopathic Parkinson’s disease (IPD) patients have abnormal visual evoked potentials (VEPs) and pattern electroretinograms (PERGs), attributed to dopaminergic transmission deficiency in visual pathway, probably the retina. VEP abnormalities are not reported in multiple system atrophy (MSA). The aim of this study was to investigate and compare chromatic (Ch) red-green (R-G) and blue-yellow (B-Y), and luminance yellow-black (Y-Bk) PERGs in patients with MSA and IPD. We investigated 6 MSA patients (mean age: 62±7.4 years) not undergoing any pharmacological treatment, as well as 12 early IPD patients (mean age: 60.1±8.3 years) and 12 age-matched normal observers. ChPERGs were recorded monocularly in response to full-field equiluminant R-G, B-Y and Y-Bk horizontal gratings. In MSA only responses to R-G stimuli showed minimal insignificant changes (slight but not significant amplitude reduction without any significant latency delay); no significant abnormality was detected for B-Y and luminance Y-Bk stimuli. By contrast, in IPD all responses were reduced in amplitude and delayed in latency, above all for B-Y stimuli. Present data indicate that both chromatic and achromatic PERGs are virtually unaffected in MSA, whereas in early IPD they are clearly impaired, suggesting different pathogenic retinal mechanisms and a useful simple tool for distinguishing MSA from IPD.     

Experimental models of reflex contractile activity in the rabbit bladder

We were able to produce two highly reproducible experimental models (in the rabbit) that demonstrated a high degree of reflex bladder contractile activity. In one model, a somatovesical reflex was induced by touching or pinching the perineal area. This reflex may be organized through a neurogenic reflex at the spinal level. In another model, rhythmic bladder contractions were produced by distal urethral constriction in the absence of bladder distension. These rhythmic contractions were thought to be due to a supraspinal reflex. In both types of contractile reflexes, intravenous administration of hexamethonium inhibited the reflex contractile activity virtually completely, intravenous atropine inhibited over 90% of the induced contractile activity, thus suggesting that these contractions were mediated reflexly through cholinergic stimulation. These two models of reflex bladder contractions should be useful for the study of hyperreflexic bladders.     

早搏联律间期缩短对血流动力学的影响

目的研究房性、室性早搏联律间期缩短与桡动脉图的关系,探讨早搏对血流动力学的影响。方法经心电图诊断为房性早搏48例及室性早搏51例,再应用心功能仪检查,通过信号处理技术对早搏桡动脉图形进行面积积分。结果①早搏桡动脉图积分面积提前率〉40%时最小,20%-40%时居中,〈20%时最大（P〈0.05）。②提前率相同情况下,左房与右房的早搏桡动脉图积分面积比较差异无统计学意义（P〉0.05）;左室与右室的早搏桡动脉图积分面积比较差异有统计学意义（P〈0.05）。③早搏时的桡动脉图积分面积最小,早搏前第一个窦性心搏居中,早搏后第一个窦性心搏最大（P〈0.05）。结论早搏对血流动力学的影响主要与早搏的联律间期长短有关,室性早搏还与其发生部位有关,早搏的代偿间歇,不能改善对血流动力学的影响。     

Scolioses idiopathiques et congénitales

Résumé D'étiologie toujours inconnue, la scoliose idiopathique de l'adolescent ne peut être traitée efficacement que si le dépistage est très précoce, entre 8 et 10 ans. La preuve de l'évolutivité angulaire doit être faite avant d'entreprendre un traitement orthopédique, dont l'objectif sera de contrôler l'aggravation liée à la poussée de croissance pubertaire. De nouveaux protocoles à temps partiel sont actuellement à l'étude et s'adresseront à des courbures peu sévères et bien réductibles. Les indications opératoires sont posées en cas d'échec ou d'intolérance au traitement orthopédique. Les limites angulaires pour de telles interventions semblent diminuer progressivement, les techniques devenant plus fiables. On accorde par ailleurs de plus en plus d'importance au plan sagittal, compte tenu de la mauvaise tolérance à long terme des lordoses thoraciques. Malgré les progrès techniques, la réalisation d'une arthrodèse solide avec une greffe abondante reste le seul garant de la stabilité angulaire. L'évolution et l'histoire naturelle des courbures congénitales du rachis sont actuellement bien connues, ainsi que les malformations viscérales habituellement associées. La surveillance radiographique dès le plus jeune âge permet d'évaluer l'asymétrie de croissance vertébrale dans le plan frontal et sagittal. Ceci permet de proposer en cas d'évolutivité un traitement à visée étiologique précoce, sous forme d'une hémi arthrodèse et épiphysiodèse convexe, antérieure et postérieure pour freiner l'hypercroissance du côté de la malformation. Pour les formes dépistées plus tardivement, une greffe postérieure avec ou sans matériel est l'indication classique, en évitant absolument toute manoeuvre de distraction qui comporte un risque de complication neurologique, en particulier en cas de composante cyphotique associée.

---

Idiopathic and congenital scoliosis

Summary The exact etiology of idiopathic scoliosis is still unknown and therefore the only way to improve the prognosis is to recommend an early screening program, between 8 and 10 years of age. Angular progression must be proven for every curve before any brace application. The goal of such a treatment is to control curve progression during the adolescent growth spur. Recent part-time bracing programs have been proposed for low angle and flexible curves. Surgery is indicated in case of failure or non compliance of the conservative treatment. Currently the angular limits for surgery seem to decrease, as a result of improved surgical techniques. Sagittal unbalance and loss of thoracic lordosis are of major importance for the treatment choice, since their poor outcome in the adult population. Despite technical improvements, the quality of a solid fusion is the most important factor for long lasting results. The natural history and evolution of congenital spine deformities have been precisely documented, as well as the frequently associated visceral problems. Repeated curve measurements in young children will evaluate the growth potential asymetry in the coronal and sagittal planes. In case of rapidly progressive curves, an early surgical treatment can be proposed, consisting in convex anterior and posterior hemiarthrodesis, producing an epiphysiodesis effect of the overgrowing convex side. For cases diagnosed in older ages, the classic indication is a posterior fusion, with or without instrumentation. It is important to avoid any excessive distraction, because of a high risk of neurological complications, especially in case of an associated kyphotic deformity.

Travail présenté aux Actualités. en Orthopédie Pédiatrique organisées par le Dr Cl. Karger, le 19 au 21 mars 1992 à Aubure