Three strains of Streptococcus pneumoniae with low-level resistance to penicillin, one strain with resistance to penicillin, and three strains susceptible to penicillin were compared. The three susceptible strains had very similar patterns of penicillin-binding components (PBCs) as detected by fluorography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gels of these strains showed four major bands and a single minor band. All of the resistant strains showed different PBC patterns from those obtained for susceptible strains. The most marked changes were observed with the most resistant strain SPR110, which showed markedly reduced intensity of PBC 3 and a reduction in intensity of PBCs 1 and 2, as well as additional bands in the region of band 2. Low-level resistant strains had band densities different from the susceptible strains principally for PBC 3. No beta-lactamase activity or plasmid was detected in the resistant strains. An apparent difference in affinity for cloxacillin was also demonstrated between some of the PBCs of susceptible strain S. pneumoniae SPS101 and resistant strain S. pneumoniae SPR110. Penicillin resistance in the low-level resistant and the resistant strains was associated with PBCs possessing different properties from those seen in the three susceptible strains. Reduction in affinity for penicillin or a reduction in the amount of a PBC protein, or both, are the probable explanations of penicillin resistance in these strains.
NoR~labour is charaeterized by a co-ordinated pattern of uterine con-"tractions and complete dilatation of the cervix within a reasonabl~ length of time. Caldeyro and Alvarez (1) in their study of normal labour found that during a contraction the intra-uterine pressure ranged between 80 and 50 ram, of mercury. According to them, the intxa-uterine pressure between contractions, i.e. the resting or basal tone of the uterus, was usually 8 to 12 mm of mercury. Their uterine tracings and recordings :showed that a normal contraction pattern started in the fundus and was of greater intensity in that region as compared to the lower segment. Thus the characteristic of normal labour, as demonstrated by these workers, is active participation of all parts of the uterus with strong synchronized contractions starting in the fundal region.In contrast to this, primary uterine inertia is characterized by a prolonged and painful first stage of labour with incomplete dilatation of the cervix a~-ter 24 to 48 hours of ineffectual incoordmate contractions. Clin'ically, this state is apparent in patients who show signs of emotional tension and fear. In these eases, both the intensity of contractions and the resting tone of the uterus between contractions, may show a great deal of variation. Moreover, the contraction waves of fundal origin, and the normal gr~chent of activilrz from the upper to the lower segment are lackitLg. Instead, an abnormally wea_c or strong anti-peristaltic contraction pattern persists. These abnormal contractions are associated with slow and painful dilatation of the cervix. Labour becomes virtually arrested after a "trying first stage and many of the patients become hysterical, uncooperative and dfltlcult to manage.MacRae (2) defined primary uterine inertaa as a frst stage of labour, which, in the absence of cephalo-pelvic chspIoportion has lasted 48 hours or more. He recognized six types. In his experience, the atonie uterus and the hffpertonie uterus with cervical achalasla were the most common.. He defined cervical achalasia as non-relaxation of the cervix despite continued severe contractions of the uterus. In his series, the condition was encountered in 8.2 percent of obstetrical cases and was more common in the emotionally hyperactive primipara. He stressed the high incidence of maternal morbidity and the high foetal loss. Asphyxm and intra-uterine infection were responsible for the foetal wastage in these cases.1effcoate (8) considered the hypertonic type of inertia to be the more common and alluded to the functional aspect of this disturbance.
GENERAL CONSIDERATIONSIT m x TRtr~ that the e~tremes of life are the most hazardous periods of our existence. Of the two cxtremes, the infant or child presents the more incalculable and inscrutable physiologJc variations to challenge the skill and ingenuity of the anaesthetast.The relahve dearth of research in ths field (13) is understandable when .we consider that in infants and children we~are dealing with such rapidly changing physiologic states that separate studies at different ages are necessary. 'We are repeatedly faced with d~[culty in establishing the borderline between normality and abnormality. More attention must, therefore, be focused on t_he development of normal standards for this per:rod when homeostasis is either not yet developed or so easily upset.The anaesthetist raust de~ with paediatric patients in countless circumstances where speculation a_ad clhlical experience must take the place of knowledge and established fact. The life and welfare of these patients depend very largely on the anaesthetast's ability to exercise instantaneous and acc~rate clinical judgment, a judgment which must be tempered by the fact that the smaller the palaent the shorter the road to disasterIn order to minimize the difflcultaes m paediatric anaesthesia, it behooves us to acqu/re at least a working knowledge of the physiologic vacillations that the infant and child are hkely to manifest. Consultation with the paeHiatrician and the internist ~s most desirable when perplexing electrolyte, fluid balance, circulatory, r~spn'atory or metabolic upsets are present in the preoperative period. Moreover, the qualified paediatnc surgeon (5) is probably better equipped to deal with the surgical problems of this age group Pxeoperative consultation and correction of physiologic upsets will protect the anaesthetist against many of the anaesthetic dtt~culties w~dch may arise; because once the patient is anaesthetized, these difficulties do not permit xecourse to laboratory findings, consultation with a colleague, or t:o the policy" of watchful waiting-so common in the other specialties. Central Nervous SystemThe hypothalamic thermostat of the paediatric patient is unstable and has a tendency towards wide dSurna][ fluctuations. High temperatures increase the IDepartment of Anaesthesia, Vancouver Grace and Burnaby General Hospitals, Vancouver British Columbia. 2An abridgement of this paper was presented at
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