Meningococcal carriage by age in the African meningitis belt: a systematic review and meta-analysis.

Meningococcal carriage dynamics drive patterns of invasive disease. The distribution of carriage by age has been well described in Europe, but not in the African meningitis belt, a region characterised by frequent epidemics of meningitis. We aimed to estimate the age-specific prevalence of meningococcal carriage by season in the African meningitis belt. We searched PubMed, Web of Science, the Cochrane Library and grey literature for papers reporting carriage of Neisseria meningitidis in defined age groups in the African meningitis belt. We used a mixed-effects logistic regression to model meningococcal carriage prevalence as a function of age, adjusting for season, location and year. Carriage prevalence increased from low prevalence in infants (0.595% in the rainy season, 95% CI 0.482-0.852%) to a broad peak at age 10 (1.94%, 95% CI 1.87-2.47%), then decreased in adolescence. The odds of carriage were significantly increased during the dry season (OR 1.5 95% CI 1.4-1.7) and during outbreaks (OR 6.7 95% CI 1.6-29). Meningococcal carriage in the African meningitis belt peaks at a younger age compared to Europe. This is consistent with contact studies in Africa, which show that children 10-14 years have the highest frequency of contacts. Targeting older children in Africa for conjugate vaccination may be effective in reducing meningococcal transmission.

Percutaneous absorption of chlorhexidine in neonatal cord care.

The percutaneous absorption of chlorhexidine during its routine use in topical antiseptic preparations used in umbilical cord care was investigated by determining plasma chlorhexidine concentrations at ages 5 and 9 days. These showed that percutaneous absorption of chlorhexidine occurred in preterm neonates treated with a 1% solution of chlorhexidine in ethanol, but not in term infants similarly treated, or in preterm infants treated only with a dusting powder containing 1% chlorhexidine and 3% zinc oxide.

Characterization of marrow granulocyte development: enzyme-specific activity profiles in response to inflammatory reactions.

Isopycnic sedimentation has been used to separate granulocytes of varying stages of maturity from the bone marrows of normal rabbits and rabbits stimulated to undergo an intense inflammatory response. The separated cell populations were in turn utilized to study the specific activities of six intracellular enzymes. The study revealed an increase with cell maturation in the specific activities of myeloperoxidase, NADPH oxidase, alkaline phosphatase and acid phosphatase in normal animals; in stimulated animals only myeloperoxidase and NADPH oxidase increased significantly with cell maturation. Glucose-6-phosphate dehydrogenase showed no change in specific activity in all animals studied. Malate dehydrogenase tended to show a specific activity decrease in the maturing cells of normal but not in those of stimulated animals.

Elimination of pethidine and bupivacaine in the newborn.

Pethidine or an epidural injection of bupivacaine are common forms of obstetric analgesia in Britain. Bupivacaine has been thought to have little effect on the fetus, but neurobehavioural studies have cast doubt on this. We therefore investigated the elimination of these drugs by babies in similar population groups. Bupivacaine was largely eliminated in just over one day, while pethidine required between 2 and 6 days. This could account for the persisting depression in babies whose mothers had received pethidine.

The role of analgesics in respiratory depression: a rabbit model.

The study of the effect of analgesics in the newborn is difficult in the clinical situation and resort must be made to animals. Pethidine given within 1 hour of delivery is believed to cause less depression than when the time interval is longer. This study investigates whether it is pethidine or its metabolites which cause respiratory depression by comparing the respiratory effects of pethidine and its metabolites in the newborn rabbit. Fentanyl and buphrenorphine were also investigated as alternative analgesics. The response in the newborn rabbit to anoxia, is periods of dyspnoea, primary apnoea, and gasping. The metabolites of pethidine increased the primary apnoea signifying depression almost as much as pethidine. Depression was also produced when anoxia was induced 5 minutes after pethidine. Fentanyl caused less depression than pethidine or its metabolites excepting normeperidinic acid. Buphrenorphine administration resulted in the least depression with little difference between the low and high doses. Thus both pethidine and its metabolites are factors in the persisting depression, while buphrenorphine compared well with pethidine and fentanyl.

The effect of narcotic and narcotic-antagonist drugs in the newborn rabbit.

The newborn rabbit responds to acute anoxia, as a result of breathing nitrogen, with successive periods of dyspnoea, primary apnoea, gasping and terminal apnoea. Pethidine caused an increase in the period of primary apnoea and a decrease in the duration and rate of gasping. When nalorphine was combined with pethidine the period of primary apnoea was still increased although the duration and number of gasps were restored to control values. Naloxone, in contrast, acted as a mild respiratory stimulant, shown as a longer phase of dyspnoea. Also it completely abolished the respiratory depression produced by pethidine. Naloxone may be preferable to nalorphine as a drug to reverse the effects of pethidine immediately after birth.

The use of dextrostix and dextrostix reflectance meters in the diagnosis of neonatal hypoglycemia.

Dextrostix is now widely used as a method of screening for hypoglycemia of the newborn. There has always been some anxiety about its accuracy for estimating very low blood sugars; this is important, since symptomatic hypoglycemia of the newborn does not usually occur until the blood glucose falls below 20 mg/dl. In 1970 a reflectance meter was introduced which would measure the colour of the strip electronically. The aim of this study was to assess the accuracy of the meter and its reliability in estimating hypoglycemia. The study was continued to investigate a new model of the reflectance meter which superseded the original one. In the pilot study using the original model, blood samples were taken from 46 babies. Readings of the Dextrostix were made by two independent observers and compared with a reading taken on the reflectance meter. These estimations were later compared with blood glucose measured by the glucose oxidase method. the meter showed a marked tendency to overestimate the blood glucose: 44 out of 46 samples were overestimated (Fig. 1, 2). In the second series 180 cord blood samples were collected. Because the intention was to study very low levels of blood glucose, the samples were allowed to stand at room temperature for several hours to allow glycolysis to occur. Again, readings were taken by two independent observers and compared with the readings taken on the new Dextrostix-Eyetone meter. The blood glucose was measured on each of the samples. There was a strong correlation (r = 0.8877, p less than 0.00005) between the blood glucose values and the readings taken from the meter, with no tendency towards overestimation (Fig. 3). A similar correlation (r = 0.8533, p less than 0.00005) was seen for the observers' readings and the chemical method, although there was a tendency to underestimate blood glucose (Fig. 4). When the meter gave an estimate of more than 20 ml/dl, in no case was the actual blood glucose in the profoundly hypoglycemic group of less than 10 mg/dl. When estimated by eye there was one case in which the blood glucose was only 7 mg/dl but the observer had estimated the result of 30 mg/dl. In order to avoid any possibility that a blood glucose was less than 20 mg/dl, it is necessary to take action on any estimate below 40 mg/dl on a Dextrostix. Despite this, Dextrostix remains a very useful method of screening for neonatal hypoglycemia, whether assessed by eye or with the new Dextrostix-Eyetone meter. the meter does give better results than estimating Dextrostix by eye, but the difference was never statistically significant.