[New mathematical method for automating the analysis of fluorescein angiograms of the human fundus]. / Novyi matematicheskii metod avtomatizatsii analiza flyuorestsentnykh angiogramm glaznogo dna cheloveka.

Specific software for digital image analysis is essential for adequate analysis and objectification of ophthalmic images, assessment of the prevalence of the pathological process, as well as for planning the amount of necessary medical intervention in various diseases. PURPOSE: To develop a method for automatic analysis of angiographic images of the fundus for early diagnosis of vascular disorders and complications in a number of ophthalmic diseases. MATERIAL AND METHODS: Initial angiograms of patients (n=117) with vascular eye diseases and in healthy condition were analyzed in automatic mode using a new mathematical approach to digital processing of fundus fluorescein angiograms based on a three-stage algorithm for extracting information from images. RESULTS: A new mathematical method has been developed for the analysis fluorescein angiograms allowing for more complete results than with visual inspection of images, with image processing taking no more than 1 second in automatic mode. CONCLUSION: The developed method is based on fundamental results of the mathematical theory of image analysis and the joint use of image processing methods, mathematical morphology and mathematical statistics. The article introduces software implementations of the developed methods and presents the automated workplace of an ophthalmologist researcher.

Chronic lung disease and cystic fibrosis phenotype in prolidase deficiency: a newly recognized association.

Six families with prolidase deficiency (PD) and chronic lung disease are reported, a previously unrecognized association. In one family with a classic cystic fibrosis (CF) phenotype, no evidence for CF Transmembrane Conductance Regulator (CFTR)-related mutations could be found. Chronic lung disease and CFTR-mutation negative CF may be associated with PD.

Measles: lessons from an outbreak.

BACKGROUND: Measles outbreaks continue to be a problem for infection control in hospitals--patients, personnel, and employee health service. Guidelines for measles outbreaks are not clear for medical personnel in the hospital. METHODS: Outbreak investigation in a university-affiliated teaching hospital. RESULTS: Four primary cases resulted in 607 staff exposures and two secondary cases. Forty-seven medical personnel were furloughed and 88 were vaccinated for measles. Minimal serologic criteria for immunity were found to be inadequate in the outbreak setting. CONCLUSIONS: We found that serologic guidelines for assessing immunity to measles are inadequate. During the outbreak, we arbitrarily doubled the acceptable enzyme-linked immunosorbent assay titers that we would consider protective, > or = 2, to decrease the possibility of further secondary cases. Employees with enzyme-linked immunosorbent assay measles titers less than 2 and without a definite history of natural measles were revaccinated with a measles vaccine. This strategy takes advantage of the anamnestic response that revaccination would confer in persons with low antibody titer.

Survey of techniques used for sterilization of facial implants.

Policies need to be developed in each institution to ensure that OR personnel alert the CSS when implants are sent to CSS for sterilization so that a spore test can be processed with each implant regardless of the method of sterilization (steam, gas, or other). Implants should be quarantined for a 48-hour negative test result when possible. It is advisable to keep a log in CSS for items that require premature release with prior notification of the physician. In situations when implants and materials must be customized during surgery, OR personnel may sterilize the unwrapped implants and materials with a spore test. Under special circumstances, such materials may be released for use before obtaining the results of the 48-hour spore test, if the special circumstances are recorded in a log in the OR. If a spore test is subsequently found to show positive results, the physician and infection control personnel should be notified by telephone by OR personnel. Opposition to these policies in institutions that have implemented them has gradually diminished as surgeons have become used to the requirements and realize the rationale. OR nurses and infection control personnel need to understand that the procedures constitute safer patient care practices and that they are in full compliance with CDC guidelines.

Yield of stool cultures, ova and parasite tests, and Clostridium difficile determinations in nosocomial diarrheas.

Stool cultures for bacterial pathogens, ova and parasites, and Clostridium difficile are usually ordered for patients with nosocomial diarrhea. In the interest of cost containment we undertook an 18-month retrospective study to assess the cost/benefit of performing each of these three tests. During the study period nosocomial diarrhea developed in 118 patients. Of 452 bacterial stool cultures ordered, only one was positive for Campylobacter jejuni and none for ova and parasites. However, of 126 cultures examined for C. difficile, 47 showed positive results. We conclude that bacterial stool culture and ova and parasite identification are not indicated for patients with nosocomial diarrhea. Elimination of these unnecessary stool tests (bacterial/ova and parasite) would have saved the hospital approximately +7530 in the 18-month study period.

Significance of fever in hospital employees.

Hospital employees are exposed to a variety of occupationally related hazards that can be categorized as infectious or noninfectious. Lost work time often results from these problems. Infection control practitioners receive many telephone calls of inquiry about these employees in terms of their transmissible infections. Little has been written concerning fever in the employee health setting. To determine the frequency of febrile illness in hospital employees, we conducted a prospective study of the employee health service from January to December 1987. Winthrop-University Hospital is a 533-bed community teaching hospital with approximately 2400 employees. During 1987, 2974 visits were made to the employee health service. Of these, 879 (30%) were for occupationally related illness or injury. Oral temperatures of greater than or equal to 100 degrees F were noted in 25 (2.8%) of the 879 visits. Fever occurred predominantly in employees with infections. Upper respiratory tract infection accounted for 268 of 544 (49%) visits for infection. In addition, 11 of 22 (50%) febrile episodes were related to upper respiratory tract infections. A total of 963 work days were lost because of illness or injury. Of these, 743 (77%) were related to an infectious illness; 67 sick days (7%) were attributed to infections with a febrile response. We conclude that fever is uncommon in our employee health care population and that upper respiratory tract infections were the single most common cause of fever. When an employee had a febrile illness, the lost work time was 9% of the total time loss because of infection.

Colonization and bacteremia related to duration of triple-lumen intravascular catheter placement.

The increased use of triple-lumen catheters has brought with it an increase in sepsis. We undertook a study to determine whether this increase was related to the length of time a catheter was in place. Culture of the fluid in each of the three lumens of all triple-lumen catheters in the medical intensive care units was done daily for a 6-month period. In 14 of 31 catheters, 28 of 93 lumens showed bacterial or fungal growth. A temporal relationship between the time a catheter was placed and the onset of catheter colonization and patient sepsis was established (p less than 0.01). Catheter colonization preceded sepsis in three of four patients who became bacteremic with the same organisms that were cultured from the lumens and the catheter tips. As a result of this study, centrally placed intravascular lines are now changed every 7 days in our institution with a noticeable decrease in line-related sepsis.

Dental instrument and device sterilization and disinfection practices.

Dental instruments and devices require sterilization or high-level disinfection. An evaluation of the implementation of such processes was undertaken. Eleven thousand questionnaires on methods used to sterilize and disinfect dental instruments were sent to dental practices and 1391 (13%) were returned for evaluation. Sixty-eight percent of respondents believed they were sterilizing their instruments, however, some of the liquid chemical products used were not suitable for sterilizing instruments, and 12% of respondents used incorrect contact times. Forty-nine percent of respondents did not challenge autoclaves with biological spores to check their function at an acceptable frequency. There were similar product and timing problems when a high-level liquid chemical disinfection was attempted. Although the return sample was small, problems were identified that can and should be corrected. This study demonstrates that the potential for person-to-person transmission of infectious agents such as the human immunodeficiency virus (HIV) and hepatitis B and C viruses via inadequately sterilized dental instrument exists depending on the prevalence of HIV in the dental practice area.

Comparison of blood cultures obtained simultaneously by venepuncture and from vascular lines.

This study was designed to compare blood cultures drawn simultaneously from a pulmonary artery line or arterial line (line) and a peripheral site by venepuncture (VP). Two or three cultures were obtained by VP and from a line during each febrile episode in 79 patients. Line blood cultures were falsely negative in 1.3% of cultures and VP blood cultures were falsely negative in 2.0%. Three point eight per cent of blood cultures drawn from lines were falsely positive (contaminated), and 1.7% of VP cultures were falsely positive. No significant correlation was found between falsely positive line cultures and a positive three-way tap culture, line in use for 4 days or more, insertion of line during an emergency. We recommend that in the critically ill patient an arterial or pulmonary artery line may be used for obtaining reliable cultures.

Disinfection of respirator tubing: a comparison of chemical versus hot water machine-assisted processing.

A comparison of machine-assisted chemical disinfection, using a glutaraldehyde solution, and machine-assisted hot water disinfection was made by placing a large inoculum (approximately 10(7) colonies of Pseudomonas aeruginosa or Acinetobacter calcoaceticus var. anitratus) in sets of tubing before processing. Machine-assisted chemical processing proved to be the most efficient method with a disinfection failure rate of 6 per cent (two positive tubes out of 35). Machine-assisted hot water processing had a disinfection failure rate of 83 per cent (44 of 53 tubes were not successfully disinfected). Some of the tubes that were disinfection failures were dried in a hot air cabinet after the initial sampling, which further reduced the colony counts in the tubing but did not totally eliminate growth except in one tube. The colony counts after drying, showed that A. anitratus was 15 per cent more sensitive to hot air drying than Ps. aeruginosa, but this was not a statistically significant reduction.

Fifth disease and other parvovirus B19 infections.

Parvovirus B19 is the etiologic agent in three diseases with clinically different presentations and implications. The first and most common disease is erythema infectiosum or fifth disease. Symptoms may vary somewhat between affected children and adults. A second type of presentation occurs in infected people who require a greater than normal replacement of red blood cells, and a third infection may affect a developing fetus. Because there is no effective treatment or vaccine, physicians and nurses should conscientiously observe universal precautions to avoid acquisition of B19 infection from patients.

Varicella zoster and herpes simplex virus infections.

There are six herpes viruses, three of which, the varicella-zoster virus and the herpes simplex viruses types 1 and 2, are of particular concern to patients and staff in critical care units. These viruses, especially in their reactivated states, may present atypically in critically ill and immune-suppressed patients, and, by the time the diagnosis is made, exposures of other patients and clinicians may have occurred. Pregnancy and immunosuppressed states can result in severe, even life-threatening varicella-zoster virus infections in susceptible adults. Similarly, nosocomial herpes simplex virus infections can have serious consequences for exposed patients and staff. An additional problem after herpes simplex virus infection is the potential of lifelong and possibly frequent recurrences. In this article, the manifestations, modes of transmission, and treatment will be discussed. Special emphasis will be placed on describing the types of patients who are at high risk of presenting with varicella-zoster virus or herpes simplex virus infection so that physicians and nurses can use appropriate preventive measures to avert nosocomial infections in patients and staff.

Acquired immunodeficiency syndrome: realistic concerns and appropriate precautions.

Few topics generate as much misinformation and fear as the acquired immunodeficiency syndrome. As a result, many physicians and nurses believe that universal testing of hospitalized patients would decrease their risk of inadvertent exposure to undiagnosed carriers of the human immunodeficiency virus (HIV). Quite the contrary may be the case. Therefore, in this article the advantages and disadvantages of routine testing are examined in relationship to established risk factors for health care personnel. Realistic concerns are discussed and appropriate precautions are stressed, while some of the myths are dispelled. These include potential transmission of HIV by saliva and mosquito bites, and the superiority of one glove material over another.

Transmissible infections in critical care.

Personnel caring for critically ill patients in emergency or trauma care settings, or in adult and pediatric intensive care units, face considerable risk of acquiring infections from their patients. Obvious infections are less hazardous than obscure, unsuspected, or unreported ones. Although postexposure prophylaxis is available in some cases, it can add its own risks for uninformed persons. Examples of inadvertent but unnecessary exposures, with their consequences, are discussed in this article. Emphasis is on how ethical and considerate behavior toward others, along with clinical awareness, diagnostic clues, and early communication with the infection control service, could have prevented these exposures and might do so in other instances.

Infection control in critical care.

Most common nosocomial infections in the intensive care setting are nosocomial urinary tract infections, nosocomial pneumonia, and intravascular line-related infections. Patients in the intensive care setting rapidly become colonized by nosocomial gram-negative organisms. The colonization of the patient precedes actual infection and provides some indicator of the microflora of the intensive care unit as well as early warning of the potential for outbreaks in the unit. Infection control in the intensive care unit is of vital importance in preventing colonization of microbes as well as in the recognition and interruption of outbreaks of nosocomial infections. In this article are discussed nosocomial infections in patients in the intensive care unit from the infection control standpoint.

Symposium on infections in the compromised host. The competent internal immune system.

As has been shown, each part of the body's immune system is an effectively functioning entity. Since the whole is so much greater than the sum of its parts, a deficit in any one system can seriously affect the function of the others leaving the host without protection against the multiplicity of external and internal challenges. Without appropriate intervention or preventive measures, serious infection and even death can result.

Nursing measures for the prevention of infection in the compromised host.

Deficits in the external and internal defense mechanisms place immune-suppressed patients at great risk of acquiring deficit-specific infections. This article will acquaint nurses, patients, and their families with the many measures that are available to them to prevent such infections and the mortality associated with them. Many of these measures can prolong the time available to patients to receive treatment that may arrest or reverse the underlying disease processes.

[Effect of optic aberrations, caused by ablation pattern decentration after laser vision correction, on visual acuity]. / Vliianie opticheskikh aberratsii, vyzvannykh detsentratsiei zony abliatsii pri lazernoi korrektsii zreniia, na ostrotu zreniia.

The aim of this work was to study the effects of subclinical ablation pattern decentration on the quality of vision after photorefractive laser surgery. Optical high order spherical and coma-like aberrations of 30 eyes were evaluated before, 1 and 3 months after photorefractive surgery (PRK and LASIK). Relationship between the size and shape of the light spot on the retina during transmission of paraxial beams through the eye and the ablation zone decentrations was estimated. The results are presented for pupil diameters of 1 and 6 mm both at the center of the retina along the optical axis and at a distance of 0.5 mm from the center. Decentration of ablation zone by less than 1 mm makes the principal contribution to induction of higher order aberrations. The relative increase factor is 3.9 and 5.1 for the coma-like and spherical aberrations, respectively. At such decentrations spatial resolution of the eye decreases as the pupil size increases, which is most pronounced even at a slight distance from the visual axis but inside the fovea.