Diarrheal deaths in children living in New Mexico: toward a strategy of preventive interventions

We reviewed 26 childhood diarrheal deaths examined by the New Mexico Office of the Medical Investigator, from 1980 through 1989, to identify circumstances surrounding the illness that might lead to strategies for prevention. Children who died were younger than 9 months of age (88%) and were from minority groups (American Indian 54%, Hispanic 23%); 12 (46%) had seen a physician within 3 days of death. Interventions to avert these deaths include educating parents to seek earlier treatment and health care providers to recognize that acutely dehydrating diarrhea can be fatal.

Critical incident reporting in an anaesthetic department quality assurance programme

The critical incident technique was introduced as an additional form of quality assurance to an anaesthetic department of a major Hong Kong teaching hospital. In one year, 125 critical incidents were reported from over 16,000 anaesthetics. The most common incidents reported concerned the airway, breathing systems, and drug administration, with inadequate checking of equipment a frequent associated factor. Human error was a factor in 80% of incidents. Critical incidents were reported for the time during which the patient was under the anaesthetist's care. The majority occurred at induction or during anaesthesia, and were reported for all surgical subspecialties. Half of the incidents were detected by the anaesthetist and one third by monitoring equipment. Although there were improvements in anaesthetic care as a consequence of increased vigilance, critical incidents still occurred. Critical incident reporting highlighted problems not otherwise covered by case and peer reviews, and complemented our quality assurance programme.

Brain proline-directed protein kinase is a neurofilament kinase which displays high sequence homology to p34cdc2

The carboxyl-terminal regions of neurofilament high (NF-H) and middle (NF-M) molecular weight proteins have been suggested to be phosphorylated in vivo by a p34cdc2-like protein kinase, on the basis of the in vivo phosphorylation site motif and in vitro phosphorylation of the proteins by p34cdc2 kinase (Hisanaga, S.I., Kusubata, M., Okumura, E. and Kishimoto, T. (1991) J. Biol. Chem. 266, 21798-21803). A novel proline-directed protein kinase previously identified and purified from bovine brain has been found in this study to phosphorylate NF-H and NF-M at sites identical to those phosphorylated by HeLa cell p34cdc2 kinase. The proline-directed kinase is composed of a 33-kDa and a 25-kDa subunit. The 33-kDa kinase subunit was partially sequenced, and degenerate oligonucleotide primers corresponding to the amino acid sequence information were used to clone the subunit by polymerase chain reaction (PCR). Two overlapping PCR products comprised a complete open reading frame of 292 amino acids. The sequence contains all features of a protein kinase, suggesting that the 33-kDa peptide represents the catalytic subunit of the kinase. The 33-kDa subunit shows high and approximately equal homology to human p34cdc2 and human cdk2, with about 58 and 59% amino acid identity, respectively. These results suggest that the brain kinase represents a new category of the cdc2 family, and that some members of the cdc2 kinase family may have major functions unrelated to cell cycle control.

Outbreaks of summer rotavirus linked to laboratory practices. The National Rotavirus Surveillance System

In temperate regions rotavirus diarrhea is a disease of the cooler months of the year, but little is known about its patterns in the summer. We report on the first year of national surveillance of rotavirus, during which we actively investigated patterns of summer activity. We obtained data on rotavirus testing from 85 laboratories in 48 states, conducted a survey of their testing practices and retested for confirmation positive specimens from laboratories reporting high rates of positivity during the summer. During 1989 participating laboratories reported 4011 specimens tested for rotavirus during July and August, of which 436 (11%) were said to be positive. Most laboratories reported low rates of positivity during these months (median percent positive, 3), but five had very high rates of summer positivity (> 30%). These five laboratories were geographically separated, and neighboring laboratories showed little rotavirus activity. Positive specimens submitted by four of these centers with high rates of summer rotavirus could not be confirmed. A survey of laboratory methods found one commercial assay (TestPack) and two laboratory practices (failure to use controls and involvement of more than six technicians in the testing process) to be associated with high rates of summer positivity. Moderate rates of positivity (11 to 30%) were fond frequently in the southwest during July and August; reference testing of specimens from these laboratories confirmed positivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and characterization of a novel proline-directed protein kinase from bovine brain

A novel protein kinase which phosphorylates a synthetic peptide substrate (RRPDAHRTPNRAF) has been purified approximately 200,000-fold from bovine brain. This peptide contains the consensus sequence for phosphorylation by the p34cdc2 kinase. The purification procedure took advantage of the phenomenon that this novel brain kinase, in partially purified extracts, chromatographed on a gel filtration column as a high molecular weight complex which dissociated in buffer containing 1 M NaCl. The purified native enzyme was estimated to be approximately 63,000, and displayed two bands of M(r) = 33,000 and 25,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On Western immunoblot, the M(r) = 33,000 peptide reacted strongly with antibodies specific for a conserved amino-terminal sequence, weakly with antibodies to the conserved PSTAIRE sequence, and not at all with antibodies to the carboxyl terminus, of HeLa cell p34cdc2. The brain kinase and p34cdc2 were similar in displaying good activity toward the parent peptide substrate, but no activity toward peptide analogues in which the -T-P- motif was substituted with either -T-G- or -T-A-. Both kinases showed marked preference in phosphorylating a peptide derived from H1 histone (KTPKKAKKPKTPKKAKKL), and both kinases could be phosphorylated by the src-family tyrosine kinase, p56lyn, purified from bovine spleen. However, the brain kinase did not co-purify with a subunit having a molecular weight corresponding to known cyclins, nor did it undergo specific interaction with p13suc1 beads, suggesting that this enzyme is distinct from p34cdc2.

Annual rotavirus epidemic patterns in North America. Results of a 5-year retrospective survey of 88 centers in Canada, Mexico, and the United States. Rotavirus Study Group

Rotavirus is the major cause of severe diarrhea in children. A recent study of hospitalizations for diarrhea in the United States suggested that the annual rotavirus epidemic may follow a regional sequence from west to east. As part of a program to establish active surveillance of rotavirus prior to the introduction of vaccines, we obtained 5 years of retrospective data on rotavirus detections from 88 centers throughout North America. Analysis of 34,644 detections indicates that the peak of the annual rotavirus epidemic occurs first in Mexico and the Southwest of the United States in late fall, goes systematically across the continent in the winter, and ends in the Northeast United States and the Maritime Provinces of Canada in the spring. When detections are grouped by region, onset of the epidemic follows the same regional sequence as the peak. To our knowledge, this is the only description of a repetitive geographic sequence for the seasonal epidemic activity of a viral agent. Further studies are indicated to determine whether climate, features of the virus itself, or other factors are responsible for this apparently unique pattern. A system of active surveillance can use this pattern to detect natural alterations in the epidemic behavior of rotavirus and to assess the impact of vaccines.

p34cdc2 kinase is localized to distinct domains within the mitotic apparatus

Antibodies to both the C-terminal and the N-terminal regions of the 34 kd serine-threonine specific protein kinase, p34cdc2, were used to study the distribution of this protein in dividing cells and isolated chromosomes of the Indian muntjac. p34cdc2 was found to be present throughout the cytoplasm of dividing cells. In addition, a portion of cellular p34cdc2 was localized to the centrosome, kinetochore, and intercellular bridge and along kinetochore-to-pole microtubules during cell division. Tubulin-denuded metaphase kinetochores retained their association with p34cdc2. The detection of p34cdc2 within a variety of domains of the mitotic apparatus, in addition to the previous reported association with the centrosome [Bailly et al., EMBO J. 8:3985-3995, 1989; Raibowol et al., Cell 57:393-401, 1989] suggests that p34cdc2 may play a role in events associated with anaphases A and B as well as with the transition between interphase and mitosis.

Dietary fat influences electric membrane properties of neurons in cell culture

1. SJL/J mice were maintained on semipurified diets which differed in the ratio of polyunsaturated/saturated fatty acid content (P/S). Exposure was from conception and was maintained for periods ranging from 6 to 34 weeks. 2. Neural cell cultures were prepared from dorsal root ganglia (DRG). After 6 and 20 days of culture, neuronal electric membrane properties were determined quantitatively by intracellular recording. 3. A number of significant differences were observed for the two dietary conditions. DRG from mice on the low-P/s diet had an increase in the rate of fall of both phases of repolarization which, in conjunction with the reduced action potential overshoot, led to a reduced action potential duration. This shift to shorter-duration action potentials was accompanied by a shift to more monophasic falling phases. The low-P/S neurons also exhibited a decreased afterhyperpolarization, decreased specific membrane resistance, and decreased membrane electrical time constant compared to high-P/S neurons. 4. It was concluded that the P/S ratio in the diet can have a significant effect on the electric properties of neurons. The high-P/S neurons tended to have action potentials with biphasic repolarizations and longer durations. In contrast, the low-P/S neurons tended to have action potentials with monophasic repolarizations and shorter durations. Moreover, the known ionic dependence of these two types of action potentials suggested that the low-P/S diet resulted in action potentials with a more exclusive Na dependence, while the high-P/S diet resulted in action potentials with both Na and Ca dependence.

Neurons in cell culture survive freezing. Effect on electric membrane properties

A preliminary technique is described for freezing and thawing of intact neural cell cultures and neural cell suspensions of adult mouse dorsal root ganglia which permitted the neurons to retain to a remarkable degree their usual morphological and electrophysiological characteristics. Determination of ten electrical membrane properties (EMP) indicated significant quantitative alterations including increased specific membrane resistance and duration of the action potential and decreased resting membrane potential. The pattern of altered EMP was discussed in terms of the possible ionic site of freezing damage.

Chronic exposure to lead causes persistent alterations in the electric membrane properties of neurons in cell culture

The effects of chronic lead (Pb) exposure on neuronal electric membrane properties (EMP) were determined using neural cell cultures of adult mouse dorsal root ganglia (DRG). Cultures were exposed to Pb concentrations ranging from 0 to 100 microM for 12 days (8 DIV to 20 DIV). EMP were determined in Pb-free medium either immediately after withdrawal (IWD), or 6 days after withdrawal (6WD) from Pb. For IWD, regression analysis indicated that a number of EMP varied significantly with increasing Pb concentration. The largest such change occurred for electrical excitability which decreased significantly with increasing Pb (P = 0.000), being reduced by approximately two-thirds for neurons exposed to 100 microM Pb; resting membrane potential increased with Pb (P = 0.000); membrane time constant decreased with Pb (P = 0.007); action potential afterhyperpolarization decreased with Pb (P = 0.023). There was also evidence that the time course of action potentials was accelerated with increasing Pb concentrations, the rate of fall of neurons with biphasic falling phases being particularly increased (P = 0.047). This general pattern of altered EMP was observed for the 6WD condition also, indicating that chronic exposure to Pb caused persistent abnormalities in neuronal membranes even after 6 days of cultivation in Pb-free medium. The patterns of alterations in EMP suggested that chronic Pb exposure caused a prolonged increase in potassium permeability. It was proposed that the latter was mediated through a Pb-induced increase in intracellular ionic calcium and the associated disruption of calcium homeostasis.