Biomedical subjects
Publications and source records attributed to B Dawson.
1. It is essential that a relationship is forged between the CNLS and parents while the baby is in the SCBU. 2. Following discharge, the emphasis of caring changes from the baby to the parents. 3. The role of the CNLS, is everchanging, as it adapts to the needs of parents.
1. The nurse's role in special care baby units must develop from one of taking charge of the baby to sharing the care with the parents. 2. Nurses in SCBUs are the babies' and parents' advocate. 3. Nurse education must emphasise the need to value parental involvement in care. 4. The ultimate goal should be the baby's integration into its family.
The urinary elimination of 4-hydroxyamphetamine (PHA) and a series of homologous 4-alkoxy-substituted amphetamines and their metabolites was examined after single and multiple oral administration to pregnant and non-pregnant mice. The metabolic profile and extent of biotransformation in a series of alkoxy analogues were affected by the size of the alkoxy side chain, multiple dosing and pregnancy. There were increased recoveries of both the substrate and the conjugated derivative of PHA during gestation. The major metabolic routes observed were O-dealkylation, conjugation, and aliphatic hydroxylation of the propoxy side chain. There was some evidence of oxidative deamination. Pregnancy did not alter the profile of the major metabolites detected by GLC and NMR spectroscopy.
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Anaerobic capacity is defined as the maximal amount of adenosine triphosphate resynthesized via anaerobic metabolism (by the whole organism) during a specific mode of short-duration maximal exercise. This review focuses on laboratory measures which attempt to quantify anaerobic capacity; it examines the evidence supporting or challenging the validity of these measures and provides research foci for future investigations. Discussion focuses on anaerobic capacity measured during running and cycling, since almost all data reviewed were collected using these exercise modes. The validity of the oxygen debts (alactic and total), maximal blood lactate and oxygen deficit as measures of anaerobic capacity was examined. The total oxygen debt, now termed the excess post-exercise consumption, was used in investigations in the 1920s and 1930s to quantify anaerobic energy production; it has since been shown to be an invalid measure of anaerobic capacity, since its magnitude is known to be influenced by factors (e.g. temperature, catecholamines, substrate cycling, lactate glycogenesis) other than those directly involved in anaerobic metabolism. Maximal blood lactate, a measure also used in some of those early investigations, is often used in exercise and sports physiology. Opinion on the utility of maximal blood lactate as an estimate of anaerobic (lactic) capacity is, however, divided. Despite problems interpreting the physiological meaning of maximal blood lactate levels (due primarily to acute changes in blood volume), this measure is still used in both research and athletic settings to describe anaerobic capacity. Its use is supported by (a) the high correlations observed between maximal blood lactate and short-duration exercise performance presumably dependent upon anaerobic capacity, and (b) the higher maximal blood lactate values observed in sprint and power athletes (who would demonstrate higher anaerobic capacities) compared with endurance athletes or untrained people. However, training-induced changes in other performance, physiological and biochemical markers of anaerobic capacity have not always been paralleled by changes in maximal blood lactate; its relatively high variability also diminishes its usefulness to athletic populations, since relatively small changes in anaerobic capacity may not be detected by a measure with such high variability. These latter findings may be partially related to the confounding influence of blood volume which often changes in response to short and long term exercise demands. Maximal blood lactate is known to be influenced by the intensity and duration of the preceding exercise bout; therefore, it is plausible that these factors may also influence the degree to which maximal blood lactate accurately reflects anaerobic capacity.(ABSTRACT TRUNCATED AT 400 WORDS)
Gas chromatographic determination of the acidic and neutral components of illicit cocaine indicated the presence of one or more common components in different samples. Isolation and examination of the spectroscopic properties of the major impurity indicated it to be N-formylnorcocaine. The material was compared with authentic material synthesized from norcocaine. N-Benzoylnormethylecgonine was also found to be present in illicit cocaine.
The object of this study was to further localize autoantigenic structures on IIb-IIIa and, if possible, to precisely identify the epitopes recognized by human autoantibodies. In this paper, we identify a 50-kD chymotryptic fragment of IIIa that is recognized by a high percentage of human autoantibodies, typified by the prototype IgG autoantibody RA, which binds to IIIa on intact platelets as well as in an immunoblot assay under nonreduced conditions. Using an immunoblot assay, a carboxy-terminal region of this fragment (33 kD) that contains the cysteine-rich domains of IIIa was found to carry the epitope(s) recognized by the prototype autoantibody RA. The amino-terminal amino acid sequence of the reduced 33-kD fragment, the smallest fragment that retains the RA epitope, is XPSQQDEXSP, and that of the reduced 50-kD fragment is IVQVTFD. This indicates that the 33-kD fragment consists of approximately 175 amino acids beginning at residue 479 and extending at least through residues 636-654, while the 50-kD fragment spans the same region but begins at residue 427. It is apparent that the 33-kD fragment is generated from the 50-kD fragment by additional chymotryptic hydrolysis but remains associated because of the multiple disulfide bonds that are characteristic of this cysteine-rich domain. Sera from 48% of patients with chronic ITP and 2 of 8 patients with acute ITP contain antibodies that bind to the 50-kD fragment in an ELISA. Antibodies of the same specificity are also found in one-third of patients with either secondary immune thrombocytopenia or apparent non-immune thrombocytopenia. We conclude that the 50-kD cysteine-rich region of IIIa is a frequent target of autoantibodies in ITP, but that such antibodies may also be present in cases of thrombocytopenia that cannot be linked to an apparent autoimmune process.
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To compare the effectiveness of training in heat and in sweat clothing in cool conditions on improving heat tolerance, two groups of active subjects (n = 6 in each) performed an interval running heat-tolerance test before and after a 7-day experimental treatment. On each treatment day the subjects attempted to complete 4 x 15 min interval treadmill running periods (a 7.5 s effort every 30 s, on 15 km h-1, 15% grade; the same exercise format as the heat-tolerance test), which were interspersed with 5-min recovery periods (total time each day = 80 min). Group 1 (heat) ran in shorts, socks and shoes in hot humid conditions, and Group 2 (sweat clothing) ran in cool conditions dressed in shorts, socks and T-shirt covered by a polyester-cotton tracksuit, over which was worn 100% nylon spray-proof pants and jacket (cotton lined) with an acrylic cloth bobble hat (beanie) on the head. Both groups displayed changes typical of heat acclimatization over the 7-day period, with significant decreases in final rectal temperature (Tr) and heart rate (HR) being evident, but no change in sweat loss. Mean skin temperature (Tsk) was similar in both groups during the training sessions (heat group: 34.8-35.7 degrees C; sweat clothing group 34.9-35.5 degrees C). After the heat-tolerance test, both groups had significantly lower Tr, Tsk and HR values than before, and sweating sensitivity (g m-2 h-1 degrees C rise in Tr) was significantly increased. There was only one significant difference between the two groups (Tsk, 20th min value). It was concluded that training in sweat clothing in cool conditions can provide the same improvements in heat tolerance as training in hot humid conditions where a fixed exercise intensity and duration are used.
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The effects of age, operative site (penoscrotal or inguinal), and the addition of epinephrine 1:200,000 to bupivacaine on duration of postoperative analgesia after caudal block were prospectively and blindly evaluated in 341 children aged 13 months to 17 yrs. At the conclusion of the surgical procedures under halothane/N2O/O2 anesthetics (n = 419), caudal blocks were performed with 0.5 ml/kg of either 0.25% bupivacaine or 0.25% bupivacaine with 1:200,000 epinephrine injected at a rate of 0.5 ml/sec. The duration of analgesia was noted by parents or nurses who had been instructed how to identify, in a standard manner, the onset of postoperative pain. The mean duration of analgesia was significantly longer in young children (P less than 0.001), in children having penoscrotal operations (P less than 0.001), and when epinephrine was added to bupivacaine (P less than 0.001). There were no major complications. The authors conclude that duration of analgesia is significantly influenced by age, operative site, and the addition of epinephrine 1:200,000 to bupivacaine.
Curvature extrema provide significant information about the shape of an image contour, such as a silhouette, and are the basis for the Hoffman-Richards codon representation for shape. This representation based on curvature easily translates into a binary string that will describe the abstract shape of any smooth image curve. The computation of the basic shape primitives requires dealing with two ever-pervasive problems: contour noise and scale. We show how contour noise can be estimated given knowledge of the shape of the filter used to compute curvature from the edge list of the contour. To handle the scale problem, we use an adaptation of Witkin's scale space. Our algorithm differs from Witkin's by using a notion of parts to set criteria for significant structures.
We have examined the effects of various topical formulations of BW 540C, a novel dual inhibitor of the cyclo-oxygenase and lipoxygenase pathways of arachidonic acid metabolism, utilizing the model of ultraviolet irradiation of guinea-pig ears. During a series of studies, BW 540C preparations were compared with a range of corticosteroids, a cyclo-oxygenase inhibitor and a placebo using both subjective and objective measurements. Results showed BW 540C base to be the best overall agent for treating the pathological changes seen in this model.
A comprehensive genetic/diagnostic survey was undertaken at a special school for the mentally retarded involving 105 patients. Cytogenetic, biochemical and clinical investigations were undertaken to establish the contribution of the genetic factors to the problem of mental retardation. Apart from obtaining information about specific children, identifying families at risk, and providing genetic counselling in nearly 50% of cases, data was obtained which could be compared with other similar surveys. According to the aetiological groupings of the patients, 6.7% could be attributed to perinatal damage, 17.1% to chromosomal defects, 4.8% to biochemical disorders, 5.7% to other genetic causes, 12.4% to other prenatal damage, 1.9% to infections, and 51.4% to unknown causes. No individual with the marker X syndrome was found in this group.
We present here a familial case of a paracentric inversion in man with a short review of the literature. A paracentric inversion of chromosome 10(q11q26) was found in the amniocytes drawn for advanced maternal age. The presence of the inversion was investigated in 35 family members in three generations. No recombinants were recognized. The significance of these data for appropriate genetic counselling and possible reproductive risks is discussed.
Epidurally administered narcotics are increasingly used to provide relief of pain in adults after major surgical procedures. This report describes the use of epidurally administered morphine for postoperative analgesia in nine pediatric patients after 15 major surgical procedures. The mean dose of morphine was 0.12 +/- 0.03 mg/kg of body weight, and the mean duration of analgesia per dose was 10.8 +/- 4.0 hours. Catheters remained in place for a mean duration of 50.3 +/- 16.0 hours. Increasing the dose of morphine to more than 0.1 mg/kg did not prolong the duration of analgesia but it did increase the frequency of side effects. No complications from placement of the catheter and no serious side effects were encountered. The postoperative requirements for narcotics were significantly less in the patients who received morphine epidurally than in those who received narcotics parenterally. Epidurally administered morphine can provide reliable postoperative analgesia in pediatric patients. The potential benefits include improved quality of pain relief at low total requirements, improved pulmonary function, and early ambulation.
Pheochromocytoma is an unusual tumor in the pediatric age group. Several aspects serve to differentiate children with pheochromocytoma from their adult counterparts. Children have fewer malignant tumors, more extraadrenal tumors, and greater bilaterality and multiplicity of tumor. Similarly, they have an increased incidence of multiple endocrine neoplasia (MEN) and familial disease. The records of 16 children (age 17 years and younger) with pheochromocytoma were evaluated. One newborn died at 36 hours of age, and a 3-year-old died four days after exploratory laparotomy. Of the 14 survivors (with an average follow-up of 8 years), three had manifestations of multiple endocrine neoplasia type 2 and two had familial pheochromocytoma only. One patient had malignant paragangliomas. Three patients had bilateral tumors; one of these had MEN. Four patients underwent operation before the use of alpha- and beta-adrenergic blockade was routine at our institution. An additional patient received blockade in preparation for the removal of the pheochromocytoma but was not prepared for preoperative angiography. Hypertensive complications were encountered in four of these five children; in one, this complication was fatal. There were no intraoperative complications in the 12 patients who had received appropriate blocking agents. Eleven of the 14 survivors are currently normotensive without the need for antihypertensive medication. Two patients have medically controlled hypertension, and one continues to have severe hypertension. An overview of this series underscores the characteristic features of pheochromocytoma in the pediatric age group. Angiography has been replaced by high-resolution computed tomography for localization.(ABSTRACT TRUNCATED AT 250 WORDS)