Collagen deposition on a preformed grid

Appearance of collagen fibrils in the cuticle was seen by electron microscopy to be preceded by fonnation of a finely filamentous matrix material. At first, the fine filaments of the matrix are unorganized. However, signs of orthogonal ordering soon appear in the most superficial portion of the cuticle, and subsequently appear more basally and closer to the underlying epidermis. Meanwhile, fibrils of different staining properties and identifiable as collagen begin to be deposited in the superficial portion of the cuticle, the same region which first showed organized fine filaments. Then, like the fine filaments before them, the collagen fibrils polymerize more basally. Collagen appears to polymerize on the preformed skeleton of fine filaments as though the fine filaments caused the collagen to assemble. Neither the polymerization nor ordering of collagen fibrils seems to require direct cellular intervention but occur first in that portion of the cuticle which is furthest away from the underlying epidermis. The fine filaments may be self ordering, extracellular macromolecules which in turn determine the polymerization of collagen fibrils.     

Bacteriological Effects of Dentifrices with and without Active Ingredients of Natural Origin

Compounds of natural origin are increasingly used as adjuncts to oral hygiene. We have adopted four distinct approaches to assess the antibacterial activity of dentifrices containing natural active ingredients against oral bacteria in several test systems. Corsodyl Daily (CD), Kingfisher Mint (KM), and Parodontax fluoride (PF) were compared to a dentifrice containing fluoride (Colgate Cavity Protection [CCP]) and one containing triclosan (Colgate Total [CT]). The growth inhibitory and bactericidal potency of the formulations were determined for 10 isolated oral bacteria. Effects of single exposures of simulated supragingival plaques were then determined by epifluorescence and confocal microscopy, while the effects of repeated exposures were quantified by viable counting. Additionally, dense plaques, maintained in continuous culture, were repeatedly dosed, and the outcome was assessed by viable counting and eubacterial DNA profiling. The test dentifrices exhibited variable specificity and potency against oral bacteria in axenic culture. Of the herbal formulations, KM caused the largest viability reductions in simulated supragingival plaques, with CT causing the greatest reductions overall. Following single exposures, CD caused moderate reductions, while PF had no effect. After multiple dosing, all formulations significantly reduced numbers of total, facultative, and Gram-negative anaerobes, but only KM and CT caused greater reductions than the fluoride control. KM also reduced counts of streptococci (rank order of effectiveness: CT > KM > CCP > PF > CD). Marked changes in eubacterial DNA profiles were not detected for any herbal formulation in dense plaques, although KM markedly reduced viable counts of streptococci, in agreement with supragingival data. While both nonherbal comparators displayed antibacterial activity, the triclosan-containing formulation caused greater viability reductions than the herbal and nonherbal formulations.     

Nipple reconstruction: the S flap

A one-stage procedure to reconstruct the nipple-areola complex is presented, with special attention given to nipple volume and projection using local dermis-fat flaps. The preliminary results have been very encouraging.     

Pneumoperitoneum in the Newborn

Between 1947 and 1964, 32 infants in the first two weeks of life were seen at The Hospital for Sick Children, Toronto, with radiological evidence of free air in the peritoneal cavity. The clinical picture and the radiological signs in these infants are described. Perforations were found at all levels of the gastrointestinal tract. The overall mortality rate was 59%. The stomach was the most common site of perforation; it occurred in 11 children, of whom five survived. Prompt surgery was essential for survival, but when immediate laparotomy is not practical, abdominal paracentesis may prove to be life-saving.     

An analysis of the partial metabolic derepression of sea urchin eggs by ammonia: the existence of independent pathways

Incubation of unfertilized eggs in ammonia has been reported to initiate such late responses to fertilization as K⁺-conductance, DNA synthesis, chromosome condensation and cytoplasmic mRNA polyadenylation. It does not initiate such early responses as Na⁺-influx and the cortical reactions. We have further analyzed this metabolic derepression and find that ammonia activation does not result in the early respiratory burst and also does not initiate the late activation of Na⁺-dependent amino acid transport. Protein synthesis is increased, similar to that following normal fertilization. This indicates that augmentation of protein synthesis is causally linked neither to the earlier Na⁺-influx, cortical reactions, and respiratory burst nor to the later activation of amino acid transport. The temporal correlation between activation of transport and increased protein synthesis is therefore coincidental. The association between increased protein synthesis and establishment of K⁺-conductance was analyzed by abolishing K⁺-conductance through acidification of the sea water. This did not affect protein synthesis, indicating that K⁺-conductance and protein synthesis are also not causally linked.There is also no obligate link between protein synthesis and chromosome condensation. Incubation in low concentrations of ammonia results in increased protein synthesis but not chromosome condensation. Higher ammonia concentrations cause chromosome condensation but with no further increase in rate of protein synthesis. This suggests a concentration-dependent hierarchy of activation.These results are consistent with the concept that the late fertilization changes are not causally linked and proceed independently of each other. As we have not been able to disassociate the early changes, they may be obligately linked and dependent on each other.     

Thoracic splenosis. Diagnosis of a case by fine needle aspiration cytology

Fine needle aspiration cytology was used to study chest wall nodules in a patient who presented with fever, cough, pleuritic chest pain and cytomegalovirus infection and who had a previous history of abdominal trauma. The finding of splenic red pulp and white pulp in the aspirate, combined with the results of a radionucleotide liver-spleen scan, led to a diagnosis of thoracic splenosis, a relatively rare condition. Splenosis is thought to result from transplantation of splenic tissue after trauma and may provide some added protection against certain infectious conditions, both of which were present in this case.