Dialyzer Reuse Following Manual Reprocessing with a New Sterilant, RenNew-D

Dialysis patients are at risk for toxicity from formaldehyde used in the reprocessing of dialyzers for reuse; therefore, replacing formaldehyde as a dialyzer sterilant would be advantageous. The potential for RenNew-D as a sterilizing agent was investigated in seven stable in-center hemodialysis patients over 20 consecutive dialyses with cuprammonium cellulose hollow-fiber dialyzers. Treatment with RenNew-D showed no toxicity to patients or dialyzers except for two blood leaks occurring in one patient. The mean number of dialyzer uses was 4.9. In all the dialyzers that passed functional testing small solute clearances were maintained with reuse. The ability of RenNew-D to improve the biocompatibility of reused dialyzers was documented with mean neutrophil counts falling to only 78% of initial values during first reuse of dialyzers processed with RenNew-D compared with a decrease in neutrophil count to 2% of initial values during first use of the same dialyzers. Our results suggest that RenNew-D may be a useful alternative to formaldehyde for the purpose of dialyzer reuse. A reuse procedure that includes processing with RenNew-D is associated with improved biocompatibility, possibly because of maintenance of the blood-derived membrane coating established during prior dialysis.     

Dental phenotype of the col1a2(oim) mutation: DI is present in both homozygotes and heterozygotes

Dentinogenesis imperfecta (DI) is a common but variable feature of osteogenesis imperfecta (OI). The Col1a2^oim mutation (oim) is a well-studied mouse model of chain deficiency OI. Heterozygous oim/+ mice have subtle skeletal fragility, while homozygous oim/oim mice have marked skeletal fragility. To further define the consequences of oim mutation, we examined teeth by light and scanning electron microscopy (SEM). The dental phenotype in Col1a2^oim (oim) mice is more severe in incisors than in molars and includes changes in pulp chamber size, tooth shape, and dentin ultrastructure. Teeth in oim/oim animals are clinically fragile, while oim/+ teeth are grossly normal. Incisor pulp chamber areas (in μm²) are: upper +/+ = 358 ± 75, lower +/+ = 671 ± 162, upper oim/+ = 161 ± 54, lower oim/+ = 156 ± 19, upper oim/oim = 6900 ± 1040, and lower oim/oim = 66 ± 62 (P < 10⁻⁵). Incisor non-pulp chamber cross-sectional areas (in μm²), reflecting dentin areas, are: upper +/+ = 39,000 ± 1670, lower +/+ = 35,600 ± 1980, upper oim/+ = 47,500 ± 2510, lower oim/+ = 26,000 ± 1830, upper oim/oim = 29,800 + 315, and lower oim/oim = 36,800 ± 3450 (P < 10⁻⁵). Ultrastructural abnormalities are more pronounced in incisors than in molars and depend on dosage of the mutant allele. These include reduction in the number and regularity of spacing of the dentinal tubules, lesser mineralization, and blurring of the boundary between peritubular and intertubular dentin. Our findings demonstrate that both oim/oim and oim/+ mice suffer from DI. The more severe incisor phenotype may reflect incisors' continuous growth.     

Comparison of polypropylene and polyethylene terephthalate (Dacron) meshes for abdominal wall hernia repair: A chemical and morphological study

For the first time, by scanning electron microscopy (SEM), polypropylene (PP) excised meshes (ethylene oxide sterilized) for abdominal wall hernia repair have been shown to be greatly damaged physically, independently of the implantation time, while the polyethylene terephthalate (PET), or Dacron, ones (gamma radiation sterilized), did not undergo alterations due to the sterilization process and were not damaged, even after long implantation periods. Fourier-Transform Infrared Spectroscopy (FTIR) study of PP and PET excised meshes, as well as of their extracts with cyclohexane, has shown the presence of species, such as squalene, palmitic and stearic acid, in some cases, cholesterol, transferred from the surrounding tissues to the polymer during the implantation period. In the case of PP meshes, these small organic molecules would reduce physical and mechanical properties of the material. A hypothesis is presented to account for the better behavior (not in the clinical sense) of PET meshes.     

Er:YAG laser modification of root canal dentine: influence of pulse duration,repetitive irradiation and water spray

. The aim of this study was to determine the effects of varying parameters of Er:YAG laser irradiation with and without water spray cooling on root canal dentine in vitro. After horizontally removing tooth crowns from extracted human teeth, roots were axially sectioned into thin slices, exposing the root canal surface. An Er:YAG laser delivered 10–30 J/cm² into a 0.4-mm diameter laser spot on the root canal surface. Single pulses of different lengths (80–280 μs) were applied with and without water spray cooling/irrigation, and sequences of three pulses at a repetition rate of 30 Hz were applied at selected pulse parameters. The irradiated samples were investigated using both confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). At most irradiation conditions, the root canal dentine surface was ablated. Three-dimensional images from CLSM revealed that the cavity walls were not smooth. Depths of the cavities revealed significant differences between the cavities. No debris was observed at the surface of cavities at any irradiation condition. Strong melting and recrystallisation, or unusually flat surfaces with open dentinal tubules were obtained with sequences of three pulses without water cooling. CLSM is an effective tool for investigation of laser effects on root canal dentine. By varying the irradiation conditions, the Er:YAG laser can induce different modifications of root canal surface, which may be very interesting for root canal preparation. Paper received 23 November 2001; accepted after revision 3 January 2002.     

The connective tissue framework in the normal prostate, B.P.H and prostate cancer: analysis by scanning electron microscopy after cellular digestion

The objective of this study was twofold: (1) to determine if a cellular digestion process can facilitate examination of the morphology of the connective tissue framework of the prostate, and (2) to examine the connective tissue framework in normal prostate tissue, benign prostatic hyperplasia (BPH) and prostate cancer. Ten prostate glands were examined. Using the Ohtani method of digestion, the cellular elements were removed. This enabled scanning electron microscopy analysis of the connective tissue framework within the prostatic tissue. Light microscopy of tissue blocks determined the histology of specimens. The prostate is supported by a highly structured network of collagen fibres. This network of fibres varies in normal and diseased states. In benign prostatic hyperplasia, the collagen network is dense, with an increased number of fibres. In prostatic adenocarcinoma, there is non-uniform swelling with a loss and disintegration of collagen fibres. In conclusion, sodium hydroxide cellular digestion provides an excellent method for demonstrating the connective tissue framework of prostatic tissue. The morphological changes in collagen fibres in normal prostate, benign prostatic hyperplasia and prostatic adenocarcinoma have implications for prostate growth in normal and diseased states. Received: 29 January 1998 / Accepted: 21 April 2000     

Pox outbreaks in Sheep and Goats at Makhdoom (Uttar Pradesh), India: Evidence of Sheeppox Virus Infection in Goats

Sheeppox and goatpox outbreaks occur often in India incurring huge economic loss to the small ruminant industry. This paper describes two sheeppox outbreaks, of which one occurred in an organized sheep breeding farm at Makhdoom (Uttar Pradesh), India, during 2007 and another in goats at the Central Institute of Research on Goats, Makhdoom (Uttar Pradesh), India during 2008. In the first outbreak, a local Muzaffarnagari sheep breed was affected (n = 477) with morbidity and mortality rates, respectively, of 100% and 53.9% accompanied by significant productivity losses. In the 2008 outbreaks, a small number of goats were affected without any mortality. The tissue and swabs collected from both the outbreaks were processed and inoculated onto Vero cells, and the causative agent of the outbreaks, capripox virus (CaPV), was isolated. The identity of the virus was confirmed as CaPV based on electron microscopy, experimental pathogenesis in sheep, capripox‐specific conventional and real‐time PCRs. Sequence analysis of the P32 envelope protein gene revealed that the causative agent of both outbreaks was confirmed as sheeppox virus (SPPV) implying SPPV infection not only in sheep but also goats in India.