Statistical Analysis with Missing Data

INTRODUCTION 149 TAXONOMY 149 Historical Features 149 Current Taxonomic Status 149 Delineation of Species 149 Species of Clinical Importance 150 LABORATORY IDENTIFICATION 150 Isolation from Clinical Specimens 150 Morphological, Cultural, and Metabolic Characteristics 151 Species Identification 151 NOSOCOMIAL INFECTIONS CAUSED BY ACINETOBACTER SPP. 152 Overview 152 Respiratory Infection 152 Bacteremia 153 Meningitis 153 Urinary Tract Infection 154 Other Miscellaneous Infections 154 PATHOGENESIS OF ACINETOBACTER INFECTIONS 154 Predisposing Factors 154 Virulence of Acinetobacter spp. 154 EPIDEMIOLOGY 155 Human Carriage 155 Persistence in the Hospital Environment 155 TYPING SYSTEMS 156 Biotyping 156 Antibiograms 156 Serotyping 156 Phage Typing 157 Bacteriocin Typing 157 Protein Profiles 157 Multilocus Enzyme Electrophoretic Typing 157 Plasmid Profiles 157 Analysis by Pulsed-Field Gel Electrophoresis 157 Ribotyping 157 PCR-Based Methods 158 CLINICAL ANTIBIOTIC RESISTANCE 158 BIOCHEMICAL AND GENETIC MECHANISMS OF ANTIBIOTIC RESISTANCE 158 Genetics of Resistance 158 b-Lactams 159 Aminoglycosides 159 Quinolones 160 Other Antibiotics 160 THERAPY OF ACINETOBACTER INFECTIONS 160 CONCLUSIONS 160 ACKNOWLEDGMENTS 161 REFERENCES 161

/pdf/acinetobacter-spp-as-nosocomial-pathogens-microbiological-430u90opiv.pdf

Acinetobacter spp. as nosocomial pathogens: microbiological, clinical, and epidemiological features.

Background Ocular trauma or disease may lead to severe corneal opacification and, consequently, severe loss of vision as a result of complete loss of corneal epithelial stem cells. Transplantation of autologous corneal stem-cell sources is an alternative to allograft transplantation and does not require immunosuppression, but it is not possible in many cases in which bilateral disease produces total corneal stem-cell deficiency in both eyes. We studied the use of autologous oral mucosal epithelial cells as a source of cells for the reconstruction of the corneal surface. Methods We harvested 3-by-3-mm specimens of oral mucosal tissue from four patients with bilateral total corneal stem-cell deficiencies. Tissue-engineered epithelial-cell sheets were fabricated ex vivo by culturing harvested cells for two weeks on temperature-responsive cell-culture surfaces with 3T3 feeder cells that had been treated with mitomycin C. After conjunctival fibrovascular tissue had been surgically removed from the ocular surfa...

https://www.nejm.org/doi/pdf/10.1056/NEJMoa040455

Corneal reconstruction with tissue-engineered cell sheets composed of autologous oral mucosal epithelium.

Herpes simplex virus (HSV) infections of humans have been documented since the advent of writing. The spectrum of disease was expanded to include primary and recurrent infections of mucous membranes (gingivostomatitis, herpes labialis, and genital HSV infections), keratoconjunctivitis, neonatal HSV infection, visceral HSV infections of the immunocompromised host, HSV encephalitis, Kaposi's varicella-like eruption, and an association with erythema multiforme. Cumulative experience suggests that factors associated with pregnancy may place both the mother and fetus at increased risk for severe infection, possibly because of altered cell-mediated immunity. The major risk to the fetus is with primary or initial genital HSV infection of the mother. PCR evaluation of cerebrospinal fluid can be utilized to monitor therapeutic outcome in patients with herpes simplex encephalitis. The use of HSV for gene therapy heralds a new era of herpes biology, the conversion of a hazardous foe into a user-friendly surgical tool. Asymptomatic shedding of virus can continue despite clinically effective suppression with acyclovir, so the possibility of person-to-person transmission persists. Newborns with HSV infections can be classified as having disease that is localized to the skin, eyes, and mouth; affects the central nervous system (CNS); or is disseminated. Drug resistance was considered rare and resistant isolates were thought to be less pathogenic until a series of acyclovir-resistant HSV isolates from patients with AIDS were characterized. The risk of nephrotoxicity can be minimized by administering acyclovir by slow infusion and ensuring adequate hydration.

/pdf/herpes-simplex-viruses-2ac5n3adkn.pdf

Herpes Simplex Viruses

Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach.

The in vivo confocal microscopy technique provides us with a real-time, non-invasive way of examining the human cornea. The most important advantage of this type of microscopy is to reveal the etiologic agents in infectious keratitis such as Acanthamoeba keratitis. We present several representative cases of Acanthamoeba keratitis, which were diagnosed in their early stages using in vivo confocal microscopy and managed based on that diagnosis. In our Acanthamoeba keratitis cases, highly-reflective round or ovoid organisms with a diameter of about 10-25 um were visualized distinctly against relatively-dark normal parenchymal structures, such as epithelial cells or keratocyte nuclei. Double-walled structures of Acanthamoeba cysts were clearly demonstrated in some cases. We can confirm that in vivo tandem scanning confocal microscopy is a powerful diagnostic tool for identifying the infecting organisms in Acanthamoeba keratitis.

In vivo tandem scanning confocal microscopy in acanthamoeba keratitis.

PURPOSE To analyze the differences in epithelial healing between limbal stem cell-deficient corneas and normal corneas by using in vivo confocal microscopy. METHODS Two different injury models were made in rabbit eyes by using n-heptanol to create a corneal epithelial defect with (limbal stem cell-deficiency model) or without (normal corneal reepithelialization model) peripheral limbal keratectomy. Using a tandem scanning confocal microscope (TSCM), we examined and compared the epithelial healing processes of the two different injury models. Impression cytology and pathologic examination were done on limbal stem cell-deficient corneas. RESULTS In limbal stem cell-deficient corneas, the healing epithelial cells were smaller and more variable in size compared with those in normal corneas. In limbal stem cell-deficient corneas, the epithelial thickness varied from one to six cell layers, with the middle and basal cell layer cells being lined up in a certain direction in some areas. The basement membrane was uneven and partially deficient; in some areas, the deep basal epithelial cells were mixed with fibrous strands extending from the anterior stroma. New vessels were located in various levels, from epithelium to deep stroma. These findings were not seen in the normal corneal reepithelialization. In both epithelial-healing models, particularly in the normal corneal reepithelialization, the superficial squamous cells in the early healing stage were considerably larger than those in nontraumatized normal corneas. CONCLUSION TSCM is a useful technique for studying the in vivo microscopic structure of many corneal diseases and injury models sequentially over time.

Tandem scanning confocal microscopic analysis of differences between epithelial healing in limbal stem cell deficiency and normal corneal reepithelialization in rabbits

Vortex Keratopathy Associated With Atovaquone

We tested the ability of 15-deoxyspergualin (DSG), a new immunosuppressant, to inhibit corneal allograft rejection in the rat penetrating keratoplasty model. Fifty-six inbred Lewis rats were recipients of orthotopic corneal allografts from Brown Norway rats. Allogeneic groups received daily intramuscular injections of DSG 2, 3, 4, or 10 mg/kg/day. The animals treated with 2 mg/kg/day had four out of 10 grafts rejected; in the 3 mg/kg/day group none of the six grafts rejected; whereas in the 4 mg/kg/day group one out of 15 grafts rejected. The animals treated with 10 mg/kg/day became emaciated and died during the second and third postoperative weeks with relatively clear grafts. All corneas rejected following discontinuation of the drug. We conclude that the systemic administration of DSG at 3 or 4 mg/kg/day results in effective suppression of corneal allograft rejection in the rat penetrating keratoplasty model.

Edward J. Holland

Papers

In vivo tandem scanning confocal microscopy in acanthamoeba keratitis.

Tandem scanning confocal microscopic analysis of differences between epithelial healing in limbal stem cell deficiency and normal corneal reepithelialization in rabbits

Vortex Keratopathy Associated With Atovaquone

Suppression of graft rejection using 15-deoxyspergualin in the allogeneic rat penetrating keratoplasty model.

Discoid Lupus Erythematosus of the Eyelid Complicated by Wound Dehiscence