Heterocyclic Phosphenium Cations and Their Divergent Coordination Chemistry.

While they are often encountered as reaction intermediates, phosphenium cations are not commonly incorporated into π-conjugated systems. We report the synthesis and characterization of donor-stabilized phosphenium cations supported by pyridylhydrazonide ligands. The preparation of these cations relies on precise control of ligand E-Z isomerism. The heterocycles were treated with a variety of transition metals, with [Rh(COD)Cl]2 yielding the only well-defined organometallic products. The optoelectronic properties of the phosphenium heterocycles and their transition-metal complexes were examined using UV-vis absorption spectroscopy, cyclic voltammetry, and modeling by density functional theory (DFT). Computations support the description of these compounds as phosphenium cations and corroborate our observation of a weak P-Npyridine bond, which was manifested experimentally as the Rh adducts undergo selective insertion of Rh into the P-Npyridine bond, depending on the substituent at phosphorus. The reported compounds provide a framework for further study of π-conjugated, N,N'-chelated phosphenium cations and their transition-metal adducts.

A Boron Difluoride Hydrazone (BODIHY) Polymer Exhibits Aggregation-Induced Emission.

Polymers that exhibit aggregation-induced emission (AIE) find use, for example, as cell-imaging agents and as fluorometric sensors due to their unique optical properties. However, the structural diversity of AIE-active polymers has not necessarily advanced at the same rate as their applications. In this work, ring-opening metathesis polymerization is used to synthesize the first example of a polymer (Mn  = 61,600 g mol-1 , D = 1.32) containing boron difluoride hydrazone (BODIHY) heterocycles in its repeating unit. The BODIHY monomer and polymer described absorb and emit in the visible region in solution (λabs  = 428 and 429 nm, λem  = 528 and 526 nm) and as thin films (λabs  = 443 and 440 nm, λem  = 535 and 534 nm). Monomer (ΦFilm  = 10%) and polymer (ΦFilm  = 6%) exhibit enhanced emission as thin films compared to solution (ΦSoln  ≤ 1%) as well as AIE upon the addition of water to DMF solutions as a result of restriction of intramolecular motion. Enhancement factors for the monomer and polymer are determined to be 58 and 15, respectively. The title BODIHY polymer exhibited an earlier onset of AIE and enhanced sensitivity to solution viscosity when compared to the parent monomer.

Etiology of nongonococcal urethritis. Evidence for Chlamydia trachomatis and Ureaplasma urealyticum.

Chlamydia trachomatis, Ureaplasma urealyticum (T-mycoplasma), and Hemophilus vaginalis have previously been considered possible etiological agents in nongonococcal urethritis (NGU). In this study, current C. trachomatis infection was confirmed by culture and (or) micro-immunofluorescence serology in 26 of 69 men experiencing afirst episode of NGU, and 1 of 39 with no urethritis. Serum IgM immunofluorescent antibody to chlamydia was demonstrated in 16 of 20 men with chlamydia culture positive NGU, and 3 of 39 with chlamydia culture negative NG, and none of 34 with no urethritis. 9 of 10 culture positive men with less than or equal to 10 days symptoms developed immunofluorescent antibody seroconversion in paired sera. U. realyticum was isolated significantly more often and in significantly higher concentration from first voided urine from chlamydia-negative cases of NGU than from chlamydia-positive NGU. Ureaplasmacidal antibody titers increased fourfold in six men, four of whom had negative cultures for for unreaplasma. H. vaginalis was isolated from c9 of 33 men with no urethritis and 2 of 69 with NGU. C. trachomatis is susceptible, and U. urealyticum is resistant to sulfonamides. A 10-day course of sulfisoxazole therapy produced improvement in 13 of 13 chlamydia-positive, unreaplasma-negative, and only 14 of 29 chlamydia-negative, unreaplasma-positive NGU cases (P less than 0.002). Thus, culture, serology, and response to therapy support the etiologic role of chlamydia in NGU. Quantitative culture and response to therapy suggest U. unrealyticum may cause many cases of chlamydia-netative NGU.

Identification of a tumor-associated antigen in cervical carcinoma by two dimensional (crossed) immunoelectrophoresis.

Two-dimensional immunoelectrophoresis was used to evaluate 8 cervical cancer speciments, 11 other gynecologic tumors, and 5 specimens of normal cervix. Antigens were water-soluble tissue extracts and antisera prepared in rabbits. When tested against antisera to cervical cancer, cancer antigens showed 14-17 precipitin lines whereas normal cervix showed 10-16. A single heavy heterogeneous precipitin line with an electrophoretic mobility of 0.58 relative to bovine albumin was observed in all cervical cancer specimens but not in normal cervical or other tumor specimens. Further evidence for the uniqueness of this antigen was sought by enhancement (addition of another antigen to the first phase of electrophoresis which increased the size of common peaks) and suppression (addition of another antiserum to the second phase, whereby the peak size of components to which both sera have antibody was decreased). The specific precipitin line was neither suppressed by the addition of antisera to normal tissue nor enhanced when normal tissue antigen was added to the tumor antigen preparation. More conclusively, adsorption of the tumor antiserum with normal tissue had no effect on the unique tumor-associated precipitin line, whereas all other precipitin lines were removed. This antigen was common to other cervical tumors because enhancement was demonstrated with three other cervical tumor specimens. The identification of a distinct and separate antigen associated with cervical carcinoma will permit further characterization and possible development of immunodiagnostic methods.

Where's the beef? The role of cross-contamination in 4 chain restaurant-associated outbreaks of Escherichia coli O157:H7 in the Pacific Northwest.

BACKGROUND: From March through August 1993, outbreaks of Escherichia coli O157:H7 occurred at 4 separate Oregon and Washington steak and salad bar restaurants affiliated with a single national chain. OBJECTIVE: To determine the cause of outbreaks of E coli O157:H7 at 4 chain restaurants. METHODS: Independent case-control studies were performed for each outbreak. Available E coli O157:H7 isolates were subtyped by pulse-field gel electrophoresis and by phage typing. RESULTS: Infection was not associated with beef consumption at any of the restaurants. Implicated foods varied by restaurant but all were items served at the salad bar. Among the salad bar items, no single item was implicated in all outbreaks, and no single item seemed to explain most of the cases at any individual restaurant. Molecular subtyping of bacterial isolates indicated that the first 2 outbreaks, which occurred concurrently, were caused by the same strain, the third outbreak was caused by a unique strain, and the fourth was multiclonal. CONCLUSIONS: Independent events of cross-contamination from beef within the restaurant kitchens, where meats and multiple salad bar items were prepared, were the likely cause of these outbreaks. Meat can be a source of E coli O157:H7 infection even if it is later cooked properly, underscoring the need for meticulous food handling at all stages of preparation.

A case-control study of necrotizing fasciitis during primary varicella.

OBJECTIVE: An increase in the incidence of necrotizing fasciitis (NF) occurring in previously healthy children with primary varicella was noted in the Washington State area between December 1993 and June 1995. Our objective was to investigate ibuprofen use and other risk factors for NF in the setting of primary varicella. METHODS: Case-control study. Demographic information, clinical parameters, and potential risk factors for NF were compared for cases and controls. Cases of NF were analyzed to identify potential determinants of NF complicated by renal insufficiency and/or streptococcal toxic shock syndrome. Multivariate logistic regression was used to evaluate the association between ibuprofen use and NF. A case was defined as a child with NF hospitalized within 3 weeks of primary varicella (n = 19). Controls were children hospitalized with a soft tissue infection other than NF within 3 weeks of primary varicella (n = 29). Odds ratios (ORs) of ibuprofen, as well as other potential risk factors were evaluated. In addition, demographic and clinical data as well as other potential risk factors were compared between cases and controls. RESULTS: After controlling for gender, age, and group A streptococcus isolation, cases were more likely than controls to have used ibuprofen before hospitalization (OR, 11. 5; 95% confidence interval, 1.4 to 96.9). In most children, ibuprofen was initiated after the onset of symptoms of secondary infection. Children with NF complicated by renal insufficiency and/or streptococcal toxic shock syndrome were more likely than children with uncomplicated NF to have used ibuprofen (OR, 16.0; 95% confidence interval, 1.0 to 825.0). Children with complicated NF also had a higher mean maximum temperature (40.9 degrees C vs 39.3 degrees C), and a longer mean duration of secondary symptoms (1.7 days vs 0.6 days) before admission than children with uncomplicated NF. CONCLUSION: Ibuprofen use was associated with NF in the setting of primary varicella. Additional studies are needed to establish whether ibuprofen use has a causal role in the development of NF and its complications during varicella.

Evaluation of the use of mass chemoprophylaxis during a school outbreak of enzyme type 5 serogroup B meningococcal disease.

BACKGROUND: A vaccine for prevention of serogroup B meningococcal disease is not available in the United States, and indications for the use of mass chemoprophylaxis for control of meningococcal outbreaks are not well-defined. In response to an outbreak of six cases of enzyme type 5 serogroup B meningococcal disease among students at a middle school, we implemented a program of mass rifampin prophylaxis and evaluated the effectiveness of this preventive measure. METHODS: Oropharyngeal cultures were obtained from 351 of the 900 students before prophylaxis; 196 participants were recultured 3 weeks later. Meningococcal isolates were subtyped and tested for rifampin susceptibility, and risk factors for disease or carriage among students were evaluated. RESULTS: No cases occurred after prophylaxis. Before prophylaxis 10% (34 of 351) of students were meningococcal carriers and 3.4% (12 of 351) carried the epidemic strain. After prophylaxis 2.5% (5 of 196) were carriers and 1.0% (2 of 196) carried the epidemic strain. Rifampin was 85% effective in eradicating carriage, and the rate of acquisition of carriage during the 3-week period was low (0.5%). Carriage persisted after prophylaxis in 4 students; 3 of these postprophylaxis isolates were rifampin-resistant. Rifampin resistance thus developed in 12% (3 of 26) of preprophylaxis isolates. Disease/epidemic strain carriage was associated with enrollment in the school band and certain other classes. CONCLUSIONS: These findings suggests that mass chemoprophylaxis may be effective and should be considered for control of school serogroup B meningococcal outbreaks. This approach is less likely to be effective for control of outbreaks affecting larger, less well-defined populations and is associated with the rapid development of antibiotic resistance.

Risk of infection with hepatitis A, B or C, cytomegalovirus, varicella or measles among child care providers.

BACKGROUND: Employment as a child care provider has been suggested as an indication for hepatitis A virus (HAV) immunization; however, whether this occupational group is at increased risk of HAV infection is not well-defined. METHODS: We obtained sera samples for testing for antibodies to hepatitis A, B and C, cytomegalovirus, varicella and measles from a sample of child care providers in King County, WA, and administered a questionnaire to assess employment characteristics and other potential risk factors for infection. We also compared the anti-HAV seroprevalence among providers with that of subjects in the Third National Health and Nutrition Survey, representative of the US general population. RESULTS: Thirteen percent (48 of 360) of providers were anti-HAV-positive (46% (22 of 47) of foreign born vs. 8% (26 of 313) of US-born (P < 0.001)). In multivariate analysis anti-HAV seropositivity was associated with foreign birth, age, income and Hispanic ethnicity but was not associated with characteristics of employment. Seroprevalence among US-born providers tended to be lower than that among Third National Health and Nutrition Survey subjects of similar age, sex, race and income. Sixty-two percent of providers were seropositive to cytomegalovirus, which was associated with nonwhite race, changing diapers > or = 3 days/week while at work and having a child in the household. Antibody prevalence was 1.4% to hepatitis B core antigen, 0.6% to hepatitis C, 94% to measles and 98% to varicella. CONCLUSIONS: The anti-HAV prevalence among US-born providers was low, and seropositivity was not associated with employment characteristics, indicating that occupational exposure to HAV is uncommon under non-outbreak circumstances.

Risk factors for invasive Haemophilus influenzae disease among children 2-16 years of age in the vaccine era, Switzerland 1991-1993. The Swiss H. Influenzae Study Group.

BACKGROUND: Continued surveillance, and detailed investigation of direct and indirect effects of conjugated vaccines and risk factors for invasive H.influenzae serotype B (Hib) disease in the vaccine era are important. METHODS: 143 cases with invasive disease between 1991 and 1993 aged 2-16 years were selected retrospectively from a large incidence trend study. Controls (n = 336) were recruited from local vital registries and matched to cases for age, gender, and residence. Hib vaccination histories among study subjects and their siblings and other sociodemographic variables were obtained by questionnaires completed by the parents of these children. Adjusted odds ratio (OR) estimates were calculated by conditional logistic regression analysis. RESULTS: Most vaccinated subjects had received the Polysaccharide-Diphtheria Toxoid vaccine and estimated vaccine efficacy was high (95%; 95% confidence interval [CI] 60-99%). Also, the results suggested that protection afforded by vaccination against Hib extended to the family members of vaccinated children. School attendance was found to be protective against invasive Hib disease (OR:0.33; CI:1.2-14.4). Cases more often than controls reported suffering from asthma and allergies (OR:4.8; CI:1.2-19.4). CONCLUSIONS: Post-licensure vaccine efficacy is high among children > or = 2 years of age. The observed association between asthma and epiglottitis is novel and deserves further investigation.

An outbreak of acute gastroenteritis in a geriatric long-term-care facility: combined application of epidemiological and molecular diagnostic methods.

OBJECTIVE: To assess possible transmission modes of, and risk factors for, gastroenteritis associated with Norwalk-like viruses (NLVs) in a geriatric long-term-care facility. METHODS: During a prolonged outbreak of acute gastroenteritis, epidemiological data on illness among residents and employees were collected in conjunction with stool, vomitus, and environmental specimens for viral testing. NLVs were identified by electron microscopy in stool and vomitus specimens, and further characterized by reverse-transcriptase polymerase chain reaction and nucleotide sequencing. Potential risk factors were examined through medical-record review, personal interview, and a self-administered questionnaire sent to all employees. RESULTS: During the outbreak period, 52 (57%) of 91 residents and 34 (35%) of 90 employees developed acute gastroenteritis. Four case-residents were hospitalized; three residents died at the facility shortly after onset of illness. A point source was not identified; no association between food or water consumption and gastroenteritis was identified. A single NLV strain genetically related to Toronto virus was the only pathogen identified. Residents were at significantly higher risk of gastroenteritis if they were physically debilitated (relative risk [RR], 3.5; 95% confidence interval [CI95], 1.0-12.9), as were employees exposed to residents with acute gastroenteritis (RR, 2.6; CI95, 1.1-6.5) or ill household members (RR, 2.3; CI95, 1.4-3.6). Adherence to infection control measures among the nursing staff may have reduced the risk of gastroenteritis, but the reduction did not reach statistical significance. CONCLUSIONS: In the absence of evidence for food-borne or waterborne transmission, NLVs likely spread among residents and employees of a long-term-care facility through person-to-person or airborne droplet transmission. Rapid notification of local health officials, collection of clinical specimens, and institution of infection control measures are necessary if viral gastroenteritis transmission is to be limited in institutional settings.

Gonorrhea in the newborn.

Gonorrhea prevalence in pregnant women in the United States is generally low (less than 1%), although the prevalence in certain subsets of the population remains a matter of concern. Rates of 10% have been found in some central city adolescent prenatal clinics. Rates as high as this are quite often found in developing countries. The risks of transmission to the newborn are well studied for ophthalmia neonatorum and are 30%-40%. The risks of disseminated gonococcal infection of the newborn (sepsis or arthritis) are unmeasured, but are clearly rare events. In developing countries, maternal gonorrheal infection has been linked to premature delivery, which had been previously suggested in earlier studies in the United States. There is no evidence that the increasing occurrence of penicillinase-producing Neisseria gonorrheae (PPNG) affects maternal-neonatal transmission other than to require alternative therapy.

Sexually transmitted diseases in children and adolescents.

Sexually transmitted diseases have an impact on children's health at three times in their development: during pregnancy or delivery (through maternal-neonatal transmission), during prepubertal childhood (through sexual transmission), and during adolescence (through sexual transmission). These phases must be considered distinctly by the physician, since not only the type of infection but also the management and long-term implications of the disease vary with the time period in which it was acquired.

Findings from case studies of state and local immunization programs.

BACKGROUND: As part of its examination of federal support for immunization services during the past decade, the Institute of Medicine (IOM) Committee on Immunization Finance Policies and Practices (IFPP) commissioned eight case studies of the states of Alabama, Maine, Michigan, New Jersey, North Carolina, Texas, and Washington; and a two-county study of Los Angeles and San Diego in California. Specifically, the IOM Committee and these studies reviewed the use of Section 317 grants by the states. Section 317 is a discretionary grant program that supports vaccine purchase and other immunization-related program activities. These studies afforded the Committee an in-depth look at local policy choices, the performance of immunization programs, and federal and state spending for immunization during the past decade. METHODS: The case-study reports were developed through interviews with state and local health department officials, including immunization program directors, Medicaid agency staff, budget analysts, and Centers for Disease Control and Prevention public health advisors to the jurisdiction. Other sources included state and federal administrative records and secondary sources on background factors and state-level trends. The case studies were supplemented by site visits to Detroit, Houston, Los Angeles, Newark, and San Diego. OBSERVATIONS: The nature of immunization "infrastructure" supported by the Section 317 program is shifting from primarily service delivery to a broader set of roles that puts the public effort at the head of a broad immunization partnership among public health, health financing, and other entities in both the public and private sectors. The rate and intensity of transition vary across the case-study areas. In the emerging pattern, service delivery increasingly takes place in the private sector and is related to managed care. "Infrastructure" is moving beyond supporting a core state staff and local health department service delivery to include such activities as immunization registries, quality improvement, and coordination with programs outside public health agencies. At the same time, the recent decline in federal Section 317 support is forcing difficult choices between old and new activities at the state and local levels. CONCLUSIONS: Immunization programs function as an organic component of the local health care financing and delivery systems of which they are a part. Immunization efforts are organized and conducted within distinctive state and local fiscal, economic, and health care contexts. Section 317 Financial Assistance grants, while playing a vital role in supporting immunization "infrastructure," have been too unstable and unpredictable to elicit the strategic planning, programming, and own-source spending that would be optimal for state and local programs. The predominant immunization function of state and local public health agencies is becoming assurance of age-appropriate immunization throughout the lifespan. To be successful in this emerging role, the health agencies must be supported with appropriate staffing, interagency collaboration, and clearly articulated authority.

Maternal and infant sexually transmitted diseases.

Sexually transmitted infection may result in serious damage to the reproductive tract of the mother, damage to the fetus, wastage of pregnancy, or illness or death of the infant. The effects of gonorrhea, Chlamydia trachomatis infection, mycoplasmal infections, group B streptococcus infections, syphilis, and viral infections are discussed separately for both mother and infant.

The impact of sexually transmitted diseases on minority populations.

Sexually transmitted diseases (STD) are more prevalent among some minority populations in the United States than they are among the white majority. Primary and secondary syphilis occurs 45 times as often among non-Hispanic blacks as among non-Hispanic whites and 13 times as often among Hispanics as among non-Hispanic whites, according to morbidity reports received in 1988 by the Centers for Disease Control. Gonorrhea is reported more commonly among some minorities, with 1988 rates per 100,000 population being 54 for whites, 1,801 for blacks, and 201 for Hispanics. The reasons for the higher incidence of STD among some minorities are unknown. Data on racial differences in behavior and disease susceptibility are meager and do not account for the observed differences. Poverty, which is more common among some minorities than among the white majority, is closely associated with the prevalence of STD and may be a link between membership in a minority population and an increased risk.

Reduced injection frequency and increased entry and retention in drug treatment associated with needle-exchange participation in Seattle drug injectors.

The association between needle exchange, change in drug use frequency and enrollment and retention in methadone drug treatment was studied in a cohort of Seattle injection drug users (IDUs). Participants included IDUs classified according to whether they had used a needle exchange by study enrollment and during the 12-month follow-up period. The relative risk (RR) and the adjusted RR (ARR) were estimated as measures of the association. It was found that IDUs who had formerly been exchange users were more likely than never-exchangers to report a substantial (> or= 75%) reduction in injection (ARR = 2.85, 95% confidence limit [CL] 1.47-5.51), to stop injecting altogether (ARR = 3.5, 95% CL 2.1-5.9), and to remain in drug treatment. New users of the exchange were five times more likely to enter drug treatment than never-exchangers. We conclude that reduced drug use and increased drug treatment enrollment associated with needle exchange participation may have many public health benefits, including prevention of blood-borne viral transmission.

Genital human papillomavirus infection. A growing concern.

HPV infections of the genital tract are one of the most common sexually transmitted viral infections in the United States. Data from STD clinics and private physicians' offices reveal that genital warts, one manifestation of genital HPV infection, have been diagnosed more frequently in recent years. Using a variety of diagnostic techniques, asymptomatic HPV infection has been identified in men and women and is probably much more common than clinically apparent infection.

Cytomegalovirus infection of the uterine cervix: local cervical infection and antibody response.

Thirty-three women were examined on three or more occasions, each at 2-month intervals. The overall recovery rate of cytomegalovirus (CMV) was 28% (60/215). CMV was recovered from 53% of the cases where the local antibody was 1 : 64 or greater but the greatest difference occurred below titers of 1 : 32. Below that level virus was recovered in less than 5%, compared to a prevalence of 35% for cases with a titer of 1 : 32 (P less than 0.001). Twenty-eight cases in whom CMV was sought underwent colposcopy examination and had cytologic smears examined by the papanicolaou method. The external uterine cervix with columnar cells only yield a CMV prevalence of 3/17 (18%). However, if colposcopy showed either atypical transformation or metaplasia the prevalence was 4/11 (36%). Similarly, it is provocative that the prevalence of CMV appears to increase with abnormal cytologic findings to 33% recovery in severe dysplasia or carcinoma in situ.