Effect of arylsulfatase A and sialidase on the biochemical and immunological properties of creatine kinase isoenzyme BB

This work describes the action of the lysosomal enzymes arylsulfatase A (EC 3.1.6.1) and sialidase (EC 3.2.1.18) on human creatine kinase (CK, EC 2.7.3.2) isoenzyme BB. The isoenzyme, which gives a positive reaction with the periodic acid-Schiff reagent, contains 12 molecules of sulfate and two molecules of sialic acid per molecule. On treatment with arylsulfatase, CK-BB lost enzyme activity but retained immunoreactivity, its isoelectric point was altered, and it was partly bound to a "Glyco-gel" affinity column. On treatment with sialidase, the isoenzyme lost activity, its immunoreactivity was decreased by 70%, and the inactivated CK-BB would not bind to either "Glyco-gel" or concanavalin A. We propose that the sulfate groups are involved in maintaining the integrity of the active site of the enzyme but are not involved in antigenic recognition sites on the molecule. Sialic acid plays an important role in both the structural pattern of the antigenic determinant and the active site of CK-BB.     

Thalidomide induced alteration in secondary structure of rat embryonic DNA in vivo

Teratogenicity of thalidomide was demonstrated in Wistar rats following a single maternal intravenous injection during the embryonic organogenetic period. When compared to day 13 embryonic DNA isolated from untreated control mothers, differences were observed in the mean wet weights of day 13 embryos from rats treated with thalidomide during days 10 or 11 of gestation, and significantly less amounts of embryonic DNA were recovered from mothers similarly treated on days 10 or 12 of their respective gestation periods. Rat embryonic DNA may be separated into two fractions by stepwise elution from benzoylated DEAE-cellulose (BD-cellulose) columns with 1.0 M NaCl (SE-DNA) and 1.8% (w/v) caffeine (CE-DNA) solutions, respectively. Other studies using bacterial, yeast, and rat liver DNA suggested that the first fraction contains native DNA, whereas the second may exhibit some degree of single-stranded character. Similar reproducible chromatographic profiles were obtained using a novel "batch method" developed for general application. Rat embryonic DNA was monitored by labelling in vivo with an i.p. injection of [methyl-3H]-thymidine (3H-TdR) during days 5, 6, and 7 of the gestation period. All samples were analysed on day 13 of gestation. A simple increase in percentage of caffeine-eluted DNA was not detected in thalidomide treated samples; however, diversity of percent (%) CE-DNA within litter was noted. Briefly, the percent CE-DNA values for embryos in one litter were ranked and arbitrarily grouped in classes with limits of mean +/- 1 SD, mean +/- 2 SD, and so on to generate a characteristic profile of percent CE-DNA distribution. The number of embryos within the range of each SD unit was expressed as a percentage of each litter. A plot of the ranges of percent CE-DNA versus percentage of each litter was used to illustrate the distribution profile of the particular litter and to be used for comparison between samples from untreated control and thalidomide and/or dimethylformamide (DMF) treated DNA. Treatment of day 12 mothers with thalidomide produced a majority of embryos having percent CE-DNA values similar to those of untreated controls with the exception of the inclusion of a second population of embryos with much higher percent CE-DNA values than those of the untreated controls. Similar treatment of day 11 animals produced a majority of embryos still having percent CE-DNA values similar to those of untreated controls and also having a second group of embryos with a lower percent CE-DNA values than those of untreated controls.(ABSTRACT TRUNCATED AT 400 WORDS)     

Networking computers

This decade the role of the personal computer has shifted dramatically from a desktop device designed to increase individual productivity and efficiency to an instrument of communication linking people and machines in different places with one another. A computer in one city can communicate with another that may be thousands of miles away. Networking is how this is accomplished. Just like the voice network used by the telephone, computer networks transmit data and other information via modems over these same telephone lines. A network can be created over both short and long distances. Networks can be established within a hospital or medical building or over many hospitals or buildings covering many geographic areas. Those confined to one location are called LANs, local area networks. Those that link computers in one building to those at other locations are known as WANs, or wide area networks. The ultimate wide area network is the one we've all been hearing so much about these days--the Internet, and its World Wide Web. Setting up a network is a process that requires careful planning and commitment. To avoid potential pitfalls and to make certain the network you establish meets your needs today and several years down the road, several steps need to be followed. This article reviews the initial steps involved in getting ready to network.     

Sterilization and disinfection in general practice in Northern Ireland.

In view of the recent trend towards more minor surgery being carried out in general practice we decided to conduct a postal survey to assess the level of knowledge of sterilization and disinfection and the use of benchtop sterilizers in general practice in Northern Ireland. The survey, of all 366 practices in the Province, was carried out in January/March 1998. One hundred and eleven (30%) completed questionnaires were returned. All practices performed at least one of a range of procedures requiring sterilization or disinfection, e.g., minor surgery 95%, cervical smear taking 98%, syringing of ears 98%. Only 76% of practices had a benchtop sterilizer and 39% did not have access to a sterile supply department (SSD); 32% of the latter had no desire to utilize such a service. Only 25% and 34% correctly identified the Medical Devices Agency (MDA) definitions of sterilization and disinfection respectively. The MDA Device Bulletin on benchtop sterilizers had been read by only 26% of respondents. There was an 86% interest in attending a workshop on sterilization and disinfection. The concepts and practice of sterilization and disinfection appear not to be clearly understood. We conclude that resources must be identified to provide appropriate education in this important area for primary care staff.     

Secondary hypoxemia exacerbates the reduction of visual discrimination accuracy and neuronal cell density in the dorsal lateral geniculate nucleus resulting from fluid percussion injury

The purpose of this study was to determine the impact of secondary hypoxemia on visual discrimination accuracy after parasagittal fluid percussion injury (FPI). Rats lived singly in test cages, where they were trained to repeatedly execute a flicker-frequency visual discrimination for food. After learning was complete, all rats were surgically prepared and then retested over the following 4-5 days to ensure recovery to presurgery levels of performance. Rats were then assigned to one of three groups [FPI + Hypoxia (IH), FPI + Normoxia (IN), or Sham Injury + Hypoxia (SH)] and were anesthetized with halothane delivered by compressed air. Immediately after injury or sham injury, rats in groups IH and SH were switched to a 13% O2 source to continue halothane anesthesia for 30 min before being returned to their test cages. Anesthesia for rats in group IN was maintained using compressed air for 30 min after injury. FPI significantly reduced visual discrimination accuracy and food intake, and increased incorrect choices. Thirty minutes of immediate posttraumatic hypoxemia significantly (1) exacerbated the FPI-induced reductions of visual discrimination accuracy and food intake, (2) further increased numbers of incorrect choices, and (3) delayed the progressive recovery of visual discrimination accuracy. Thionine stains of midbrain coronal sections revealed that, in addition to the loss of neurons seen in several thalamic nuclei following FPI, cell loss in the ipsilateral dorsal lateral geniculate nucleus (dLG) was significantly greater after FPI and hypoxemia than after FPI alone. In contrast, neuropathological changes were not evident following hypoxemia alone. These results show that, although hypoxemia alone was without effect, posttraumatic hypoxemia exacerbates FPI-induced reductions in visual discrimination accuracy and secondary hypoxemia interferes with control of the rat's choices by flicker frequency, perhaps in part as a result of neuronal loss and fiber degeneration in the dLG. These results additionally confirm the utility of this visual discrimination procedure as a sensitive, noninvasive means of assessing behavioral function after experimental traumatic brain injury.     

Infants born to narcotic dependent mothers: Physical growth patterns in the first 12 months of life

Objectives: To describe the physical growth patterns of infants born to narcotic dependent mothers (INDM) over a 12 months period and, if possible, to relate the growth to drug taking patterns during pregnancy.
Methodology: The growth of a cohort of 43 INDM was measured during the first 12 months of life. Weight and length measurements were compared with percentile charts and converted to Z scores. Questionnaire data about drug taking practices, demographic variables and the neonatal period (including withdrawal scores) were obtained.
Results: Twenty-four (55.8%) of INDM had evidence of neonatal drug withdrawal requiring treatment with phenobarbitone. At birth, Z scores for weight and length indicated relative intrauterine growth retardation. By 12 months, there had been some catch up growth, but Z scores for weight and length were still below zero. Persistent weight retardation at 12 months was correlated with methadone dosage during pregnancy, but not the need for phenobarbitone therapy.
Conclusions: The growth patterns of INDM in the first 12 months of life indicated that at birth there was evidence of intrauterine growth retardation, but by 12 months the growth was little different from the rest of the community. There appears to be some influence of narcotic agents taken while pregnant on subsequent growth of INDM.     

The role of T-cells in radiation pneumonitis after bone marrow transplantation

Radiation pneumonitis is a frequent complication of bone marrow transplantation. In limiting the effective dose that can be given, it decreases the chances of cancer cell destruction and of graft acceptance. The incidence of radiation pneumonitis is increased if graft-versus-host disease or infection is present, presumably due to an interaction between T-cell-mediated and radiation-mediated damage. Even in the absence of graft-versus-host disease and infection, we have found that syngeneic T-cells can contribute to radiation pneumonitis in a bone marrow transplant setting. The incidence of radiation pneumonitis was higher after whole-body irradiation and bone marrow transplantation than after whole-thorax irradiation. In the former situation, but not the latter, prior thymectomy decreased the incidence of radiation pneumonitis. It is hypothesized that autoreactive T-cells escape induction of self-tolerance during regression of the immune system after whole-body irradiation and, because autoregulatory cells are eliminated, they can contribute to radiation pneumonitis. If this concept is correct, it provides another possible explanation for the sensitivity of the lung to post-transplant pneumonitis and suggests new strategies to limit the incidence of this serious transplant-related complication.