SUMMARYBurns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.
Exposure of male Albino Swiss rats to the nonsteroidal antiandrogen flutamide during the period from gestational day (d) 10 to birth resulted in feminisation of the external genitalia and the suppression of growth of the male reproductive tract. In adulthood, testes were found to be located in diverse positions. True cryptorchidism occurred in 10 % of cases, whereas 50 % of testes descended to the scrotum and 40 % were located in a suprainguinal ectopic region. Varying degrees of tubule abnormality were seen in the testes of flutamide-treated animals, ranging from completely normal tubules with full spermatogenesis (and the expected frequency of the stages of spermatogenesis) to severely abnormal tubules lined with Sertoli cells only. For each individual testis, the overall severity of tubule damage was strongly correlated with its adult location, with intra-abdominal testes worst affected and scrotally-located testes least ; only the latter contained normal tubules. Similarly, intra-abdominal testes were the smallest in weight and contained the least testosterone. By contrast, postnatal treatment of male rats with flutamide from birth to postnatal d 14 did not impair development of the external genitalia, the process of testicular descent or adult spermatogenesis. These findings confirm that androgen blockade during embryonic development interferes with testicular descent but also demonstrate that (1) prenatal flutamide treatment per se has a detrimental effect on adult testis morphology but (2) the degree of abnormality of the testes is strongly influenced by location.
Recent work in animal models of human diffuse axonal injury has generated the hypothesis that, rather than there being physical disruption of the axolemma at the time of injury, a pertubation of the membrane occurs, which leads, over time, to a dysfunction of the physiology of the axolemmal. This dysfunction is posited to lead to a disruption of ionic homeostasis within the injured axon, leading to secondary axotomy some hours after the initial insult. We decided to test the hypothesis that membrane pump/ion channel activity or function is compromised and this would be reflected in structural changes within the axolemma and myelin sheath. We used freeze fracture and cytochemical techniques to provide evidence for change in membrane structure and the activity of membrane pumps after nondisruptive axonal injury in the adult guinea pig optic nerve. Within 10 min of injury, structural changes occurred in the distribution and number of intramembranous particles (IMPs) in the internodal axolemma. By 4 h, there was novel labeling for Ca-ATPase membrane pump activity at the same site. There was loss of IMPs from the nodal axolemma extending over several hours after injury. There was loss of both membrane pump Ca-ATPase and p-nitro-phenylphosphatase (p-NPPase) activity of the node. There was loss of ecto-Ca-ATPase activity but increased labeling for p-NPPase activity at sites of dissociation of compacted myelin. Quantitative freeze-fracture demonstrated statistically significant changes in membrane structure. We provide support for the hypothesis that structural and functional changes occur in the axolemma and myelin sheath at nondisruptive axonal injury.
Olfactory neuroepithelium of adult vertebrates retains a population of basal stem cells capable, throughout life, of dividing and differentiating into mature olfactory receptor neurons (see Farbman, 1994). The rate of turnover of olfactory receptor neurons is influenced, in part, by environmental conditions (Hinds et al. 1984). The olfactory system is known, however, to undergo a general decline in function with age. Age‐related changes have been described in the rat olfactory bulb, with a decline in size in later life (Hinds & McNelly, 1981). However, this was thought to be secondary to changes within the olfactory epithelium as changes in the number of olfactory receptor neurons directly influence the size of the olfactory bulb. Thus the primary deficit in declining olfactory function may reside in the olfactory epithelium. Studies in humans demonstrated that olfactory function diminishes with increasing age (Ship et al. 1996), suggesting a possible decrease in the number of olfactory sensory neurons. Although the structure of both developing and mature olfactory epithelium (Farbman, 1994) have been well characterised, less information exists on changes relating specifically to ageing. A reduction in thickness of the olfactory epithelium was evident in ageing humans, with a concomitant loss of the normal zonal distribution of supporting and sensory cell nuclei, a less well defined boundary between respiratory and sensory epithelia, and an increase in pigment granules within the supporting cells (Naessen, 1971). Similar lysosome‐like inclusion bodies were also noted in olfactory epithelium of adult rabbits (Mulvaney, 1971) and dogs over the age of 17 y (Hirai et al. 1996). Decreases both in the total area of olfactory epithelium and in dendritic knob density have been described in rats aged 29 mo and above (Hinds & McNelly, 1981). This is unlikely to be due to a loss of regenerative capacity since, in hamsters, regeneration of olfactory receptor neurons is observed in aged animals (Morrison & Costanzo, 1995). A scanning electron microscopic comparison of young and old rat olfactory epithelium revealed changes in membrane‐limited dense bodies in olfactory receptor neuronal cell bodies (Naguro & Iwashita, 1992). In old rats (21 and 36 mo), large irregular bodies were found in the supranuclear area of olfactory receptor neurons and were also abundant throughout the sustentacular cells, resulting in cell enlargement and the loss of about 2 layers of olfactory receptor neuron perikarya. They contained lipid droplets and numerous irregular osmiophilic lamellae resembling lipofuscin granules (Naguro & Iwashita, 1992). No attempt was made to quantify these age related changes. The present study aimed to detail fully the morphological changes in the aged mouse olfactory epithelium and is a continuation of a previous pilot study (Appleton et al. 1996).
The little previous work on the influence of vasectomy on the guinea pig testis has given controversial results. One group reports that the guinea pig suffers autoimmune orchitis while others claim damage may be mechanical. To clarify the issue, this study compares the morphology of seminiferous tubules 3 years after left unilateral vasectomy (8 guinea pigs) and control sham operation (6 animals). Grossly, left and right testes following left‐sided vasectomy were similar to controls and not significantly different in weight. On histology, left and right experimental testes and the control material showed various degrees of seminiferous tubular degeneration, including intraepithelial vesicle formation, loss of germ cells and intraluminal macrophages. Although vesicle formation was striking in most testes, quantitative analysis indicated that it was more frequent in the ipsilateral testis following unilateral vasectomy. It seems that vasectomy had exacerbated an age‐related phenomenon. Lymphocytic infiltration was seen in five of the left testes following vasectomy, in two of the corresponding right testes, but in none of the controls. Two vasectomized left testes, however, showed atrophic changes but no lymphocytic invasion. The results suggest that autoimmune orchitis follows vasectomy but that it may not be the primary cause of degeneration. Attempts to gain positive evidence for mechanical damage, however, were inconclusive. Clin. Anat. 12:250–263, 1999. © 1999 Wiley‐Liss, Inc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.