Parent development

Today's parents tend to be overwhelmed with advice from many sources. In his role as family counselor, the pediatrician must understand and consider the emotional development of parents in relation to their child's development; otherwise, his advice and counsel do not "take" and he becomes tired and frustrated and angry. PARENTS PROGRESS THROUGH DEFINITE STAGES OF DEVELOPMENT: Stage 1: Learning the cues-the struggle of the parents to interpret the infant's needs. Stage 2: Learning to accept growth and development-the parent learning to accept some loss of control of the toddler. Stage 3: Learning to separate-the parent learning to allow the child to develop independently. Stage 4: Learning to accept rejection, without deserting-the struggle of the parents not to intrude and yet to be there when needed. Stage 5: Learning to build a new life having been thoroughly discredited by one's teenager-the parent learning to live independently while the teenager struggles to develop his own identity.The pediatrician who is accepting, sensitive and a good listener and who keeps in mind that parents as well as children have capacities for growth and development, will be a potent factor in promoting good parent-child relationships and many times more effective in dealing with the child in health and disease.     

Adrenalectomy for control of cancer of the breast

Bilateral oophorectomy and adrenalectomy were used in the treatment of ten patients with advanced metastatic carcinoma of the breast, and particular attention was given to preoperative and postoperative management by a team of specialists including surgeons, endocrinologist, radiologist and pathologist. Objective and gratifying clinical remissions were achieved in three of the ten patients in this series following total oophorectomy and adrenalectomy. The remaining seven patients all subsequently died of metastatic disease. There were no operative deaths. Known cerebral or hepatic metastasis contraindicates adrenalectomy for metastatic cancer of the breast. Five of the seven patients not benefited by the operation had either cerebral or hepatic metastasis. The best candidates for adrenalectomy are premenopausal women who have previously had a clinical remission following oophorectomy and who have subsequently relapsed. The indications for adrenalectomy in the postmenopausal woman are not clear.     

Short-Term Nitrate Effects on Hydroponically-Grown Soybean cv. Bragg and its Supernodulating Mutant: II. DISTRIBUTION AND RESPIRATION OF RECENTLY-FIXED 13C-LABELLED PHOTOSYNTHATE

Fully symbiotic or nitrate treated (3 d, 4·0 mol m^–3)soybean (Glycine max [L.] Merr.) cv. Bragg and a nitrate tolerantsupernodulating soybean mutant nts 1007 were exposed to ¹³Cenriched CO₂ for a period of 10 h. During this period and forthe subsequent 24 h, continuous measurements of ¹³CO₂ and ¹²CO₂evolution of their root systems were undertaken. Three harvestsduring the experiment allowed determinations of the distributionof recently fixed carbon in different plant organs. These measurementsindicated higher dependence of N₂ fixation in nts 1007 on recentlyfixed carbon (RFC) by showing elevated RFC concentrations innodules as well as their augmented respiration. Root respirationof both genotypes was generally more reliant on stored carbon. Nitrate induced in all measured parameters a clear responsein the mutant analogous to the wild type, but quantitative differencesremained throughout. Nodule respiratory activity, the relativespecific activity (RSA), and the utilization of RFC were substantiallyreduced, but remained higher in nts 1007 than in Bragg, whilethe demand of roots for RFC increased in Bragg more than inthe supernodulator. The elevated carbon requirement of the nodulecomplement of the mutant and a high dependence on recently fixedcarbon could be attributed to higher nodule growth and maintenancecosts of the supernodulating genotype and were not associatedwith augmented nitrogen fixation activity. This less efficientutilization of carbon and the associated almost parasitic characterof the nodule complement of nts 1007 is considered to be thecause of reduced growth of the mutant. No evidence was foundfor a physiologically based nitrate tolerance in terms of nitrogenfixation. Key words: Glycine max, nitrate, N₂fixation, respiration, carbon partitioning, steady-state labelling     

Reproductive interactions of the Shiny Cowbird Molothrus bonariensis and the Yellow-hooded Blackbird Agelaius icterocephalus in Trinidad

The reproductive interactions of the Shiny Cowbird Molothrus bonariensis , a brood parasite, and the Yellow-hooded Blackbird Agelaius icterocephalus , a host of the cowbird, were studied In Trinidad, West Indies. We gathered information on the breeding biology of the Shiny Cowbird and the Yellow-hooded Blackbird, the frequency of use of the host species, and the effects of brood parasitism on host breeding success. Yellow-hooded Blackbirds are polygynous for the most part; males build nests and attempt to attract females to lay in them by means of song and visual displays directed towards the nests. This behaviour probably makes it easy for cowbirds to locate breeding birds and their nests. Cowbird eggs were found in 153 of 377 (40–3 %) blackbird nests located before the nestling stage. Shiny Cowbird parasitism of the Yellow-hooded Blackbird had little negative impact on host reproductive success, whereas predation accounted for the majority of nest failures. Vigilant nest defense by male blackbirds combined with colonial breeding apparently also minimized the extent of host egg damage and removal by cowbirds, and the parasitized and unparasitized nests were equally successful at producing blackbirds. Cowbirds most frequently parasitized the first or only nesting attempts in blackbird territories, and first or only nests were also successful more frequently than subsequent nests.     

Image analysis of aerial photography to quantify changes in channel morphology and instream habitat following placer mining in interior Alaska

1. ‘Placer’ mining for alluvial deposits of gold in a number of stream systems in interior Alaska represents a major disturbance to the stream bed and affects habitat for biotic communities. 2. The potential of analysing aerial photographs to map changes in channel habitat and morphology within gravel-bed rivers is outlined with reference to the impact and recovery of Faith Creek, a second-order stream with a history of placer mining. 3. A strong correlation between the reflectance of the channel bed and water depth is necessary to use the technique succesfully, together with a knowledge of the effects of ‘broken’water on the spectral characteristics of rivers. 4. Image analysis demonstrated that a wide range of water depths and instream mesoscale habitats existed prior to mining. During mining, the stream was confined to a channellized reach with negligible deep water or habitat diversity. 5. Since mining ceased the stream has abandoned its channellized course and formed a new channel with few deep pools. It is suggested that geomorphological recovery and associated habitat recovery takes a number of large flood events and is likely to require more than 10 years.     

The ground parrot (Pezoporus wallicus Kerr) in south-eastern Australia: a fire-adapted species?

The ground parrot (Pezoporus wallicus) has a coastal distribution in Victoria and has declined in range since European colonization. Its habitat consists of two major vegetation communities: coastal heathland and sedgeland. These are further divided into various sub-communities. These habitats contained high densities of cyperaceous and restionaceous plants, the seeds of which form the bulk of the bird's diet. Seeds and small fruits of some dicotyledonous plants and grasses are also eaten. Seed production by sedges remains fairly constant over time in sedgelands but varies in heathland, depending on time since burning. This variation is reflected by parallel changes in ground parrot population density. Both long unburnt and very frequently burnt heathlands are unsuitable for ground parrots. The birds also require dense vegetation cover. Ground parrots appear to live in territorial breeding pairs with enforced natal dispersal. This is an adaptation to an environment where habitat is patchily distributed in space and variable in quality over time.     

Algal nitrogen fixation in Californian streams: diel cycles and nocturnal fixation

Thirty-six hour diurnal studies of Ng-fixation by Nostoc in a rocky-bedded stream were carried out during the peak of the seasonal cycle of growth on clear and cloudy days in 1971 and 1972. On both occasions an unexpected pattern of N₂-fixation occurred with maximum fixation rates in the light but also in the dark portion of the day, with lowest fixation periods in the early evening. I postulate that competition for reductant between nitrogenase and other processes, especially photorespiration, controls this unusual diel cycle rather than variations in the intracellular N-pool. N₂-fixation rates on a cloudless May day in 1971 ranged from 0.2 to 4.8 nmoles C₂H₄ cm⁻² h⁻¹ and from 0.3 to 3.3 nmoles C₂H₄ mg⁻¹ h⁻¹ dry weight of Nostoc, depending on time of day and favourableness of site. On the same site on a cloudy, rainy May day in 1972 fixation ranged from 0.5 to 3.1 nmoles C₂H₄ mg⁻¹ h⁻¹ dry weight, and from 1 to 4.5 nmoles C2H4 mg⁻¹ h⁻¹ ash-free dry weight of Nostoc. Since Nostoc is most abundant in unshaded areas, and since one-third of each day's nitrogen i s fixed in the dark, future studies should take dark fixation into account.     

Effect of the Antiphagocytic Agent Cytochalasin B on Macrophage Invasion by Leishmania mexicana Promastigotes and Trypanosoma cruzi Epimastigotes*

Unstimulated mouse peritoneal exudate cells were cultured on coverslips in Medium 199 containing 10% (v/v) calf serum. Cytochalasin B dissolved in dimethyl sulphoxide (DMSO) and diluted in Medium 199 was added to cultures to give final concentrations of 1, 5 and 10 μg/ml. Equal numbers of Leishmania mexicana promastigotes, Trypanosoma cruzi epimastigotes and sheep red cells were added to 24 hr cultures incubated at 37 C. The macrophage monolayers were fixed and stained at various time intervals. L. mexicana promastigotes and sheep red blood cells were found to attach to macrophages in the presence of the drug but did not enter the cells. When the medium containing the Cytochalasin was replaced with normal medium phagocytosis of the adherent parasites and red cells followed rapidly. T. cruzi epimastigotes were found inside macrophages in both drug-treated and drug-free cultures although the number found to be intracellular in the latter was significantly greater. This study suggests that L. mexicana promastigotes enter macrophages by being phagocytosed, whereas T. cruzi epimastigotes can actively penetrate these cells.