Nephronophthisis and retinal degeneration in tmem218-/- mice: a novel mouse model for Senior-Løken syndrome?

Mice deficient in TMEM218 (Tmem218(-/-) ) were generated as part of an effort to identify and validate pharmaceutically tractable targets for drug development through large-scale phenotypic screening of knockout mice. Routine diagnostics, expression analysis, histopathology, and electroretinogram analyses completed on Tmem218(-/-) mice identified a previously unknown role for TMEM218 in the development and function of the kidney and eye. The major observed phenotypes in Tmem218(-/-) mice were progressive cystic kidney disease and retinal degeneration. The renal lesions were characterized by diffuse renal cyst development with tubulointerstitial nephropathy and disruption of tubular basement membranes in essentially normal-sized kidneys. The retinal lesions were characterized by slow-onset loss of photoreceptors, which resulted in reduced electroretinogram responses. These renal and retinal lesions are most similar to those associated with nephronophthisis (NPHP) and retinitis pigmentosa in humans. At least 10% of NPHP cases present with extrarenal conditions, which most often include retinal degeneration. Senior-Løken syndrome is characterized by the concurrent development of autosomal recessive NPHP and retinitis pigmentosa. Since mutations in the known NPHP genes collectively account for only about 30% of NPHP cases, it is possible that TMEM218 could be involved in the development of similar ciliopathies in humans. In reviewing all other reported mouse models of NPHP, we suggest that Tmem218(-/-) mice could provide a useful model for elucidating the pathogenesis of cilia-associated disease in both the kidney and the retina, as well as in developing and testing novel therapeutic strategies for Senior-Løken syndrome.

Congenital hydrocephalus in genetically engineered mice.

There is evidence that genetic factors play a role in the complex multifactorial pathogenesis of hydrocephalus. Identification of the genes involved in the development of this neurologic disorder in animal models may elucidate factors responsible for the excessive accumulation of cerebrospinal fluid in hydrocephalic humans. The authors report here a brief summary of findings from 12 lines of genetically engineered mice that presented with autosomal recessive congenital hydrocephalus. This study illustrates the value of knockout mice in identifying genetic factors involved in the development of congenital hydrocephalus. Findings suggest that dysfunctional motile cilia represent the underlying pathogenetic mechanism in 8 of the 12 lines (Ulk4, Nme5, Nme7, Kif27, Stk36, Dpcd, Ak7, and Ak8). The likely underlying cause in the remaining 4 lines (RIKEN 4930444A02, Celsr2, Mboat7, and transgenic FZD3) was not determined, but it is possible that some of these could also have ciliary defects. For example, the cerebellar malformations observed in RIKEN 4930444A02 knockout mice show similarities to a number of developmental disorders, such as Joubert, Meckel-Gruber, and Bardet-Biedl syndromes, which involve mutations in cilia-related genes. Even though the direct relevance of mouse models to hydrocephalus in humans remains uncertain, the high prevalence of familial patterns of inheritance for congenital hydrocephalus in humans suggests that identification of genes responsible for development of hydrocephalus in mice may lead to the identification of homologous modifier genes and susceptibility alleles in humans. Also, characterization of mouse models can enhance understanding of important cell signaling and developmental pathways involved in the pathogenesis of hydrocephalus.

Comparative pathology of murine mucolipidosis types II and IIIC.

UDP-GlcNAc: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) is an alpha(2)beta(2)gamma(2) hexameric enzyme that catalyzes the first step in the synthesis of the mannose 6-phosphate targeting signal on lysosomal hydrolases. In humans, mutations in the gene encoding the alpha/beta subunit precursor give rise to mucolipidosis II (MLII), whereas mutations in the gene encoding the gamma subunit cause the less severe mucolipidosis IIIC (MLIIIC). In this study we describe the phenotypic, histologic, and serum lysosomal enzyme abnormalities in knockout mice lacking the gamma subunit and compare these findings to those of mice lacking the alpha/beta subunits and humans with MLII and MLIIIC. We found that both lines of mutant mice had elevated levels of serum lysosomal enzymes and cytoplasmic alterations in secretory cells of several exocrine glands; however, lesions in gamma-subunit deficient (Gnptg(-/-)) mice were milder and more restricted in distribution than in alpha/beta-subunit deficient (Gnptab(-/-)) mice. We found that onset, extent, and severity of lesions that developed in these two different knockouts correlated with measured lysosomal enzyme activity; with a more rapid, widespread, and severe storage disease phenotype developing in Gnptab(-/-) mice. In contrast to mice deficient in the alpha/beta subunits, the mice lacking the gamma subunits were of normal size, lacked cartilage defects, and did not develop retinal degeneration. The milder disease in the gamma-subunit deficient mice correlated with residual synthesis of the mannose 6-phosphate recognition marker. Of significance, neither strain of mutant mice developed cytoplasmic vacuolar inclusions in fibrocytes or mesenchymal cells (I-cells), the characteristic lesion associated with the prominent skeletal and connective tissue abnormalities in humans with MLII and MLIII. Instead, the predominant lesions in both lines of mice were found in the secretory epithelial cells of several exocrine glands, including the pancreas, and the parotid, submandibular salivary, nasal, lacrimal, bulbourethral, and gastric glands. The absence of retinal and chondrocyte lesions in Gnptg(-/-) mice might be attributed to residual beta-glucuronidase activity. We conclude that mice lacking either alpha/beta or gamma subunits displayed clinical and pathologic features that differed substantially from those reported in humans having mutations in orthologous genes.

A community waterborne outbreak of salmonellosis and the effectiveness of a boil water order.

OBJECTIVES: A 1993 large water-borne outbreak of Salmonella typhimurium infections in Gideon, Mo, a city of 1100 with an unchlorinated community water supply, was investigated to determine the source of contamination and the effectiveness of an order to boil water. METHODS: A survey of household members in Gideon and the surrounding township produced information on diarrheal illness, water consumption, and compliance with the boil water order. RESULTS: More than 650 persons were ill; 15 were hospitalized, and 7 died. Persons consuming city water were more likely to be ill (relative risk [RR] = 9.1, 95% confidence interval [CI] = 2.9, 28.4), and the attack rate increased with increased water consumption. S. typhimurium was recovered from samples taken from a city fire hydrant and a water storage tower. Persons in 31% (30/ 98) of city households had drunk unboiled water after being informed about the boil water order, including 14 individuals who subsequently became ill. Reasons for noncompliance included "not remembering" (44%) and "disbelieving" (25%) the order. CONCLUSIONS: Communities with deteriorating water systems risk widespread illness unless water supplies are properly operated and maintained. Effective education to improve compliance during boil water orders is needed.

Family environment, attitudes toward life and death, depression, and suicidality in elementary-school children.

This study examines whether perception of family environment, attitudes toward life and death, and depression predict suicidality in elementary-school children. Seventy-eight participants ages 8 to 13 recruited through an elementary school and a university were assessed for attitudes toward life and death, depression, suicidality, and family environment. A regression equation indicated that depression and attraction to life were the only variables accounting for variance in suicidality (49%). Family environment variables were moderately correlated with depression, indicating that family environment may play a role in the development and maintenance of depression, of which suicidality is a symptom. Concurrent treatment of family issues may not only ameliorate children's symptoms, but also provide a critical sense of support that may decrease the likelihood that these children will become suicidal in the future.

Relationship between dental and general health behaviors in a Canadian population.

OBJECTIVES: Because the promotion of healthier life styles has become a public health issue of increasing interest, a survey was conducted to compare levels of preventive oral and general health behaviors. METHODS: A randomly selected population of voters aged 19 years and older living in a multicultural suburb of metropolitan Toronto, Canada, participated in a mail survey. RESULTS: Dentate respondents (n = 976) reported high optimal levels for at least daily toothbrushing (96%); moderate levels of preventive yearly dental examination (69%); and low levels for flossing (22%), using an interdental device (25%), not snacking between meals (12%), and consuming fewer than two cariogenic foods on the previous day (26%). For the general health behaviors, the majority did not smoke (75%), had low alcohol intake (89%), used seat belts (69%), and exercised three times weekly (50%). Additive indices for the oral and general health behaviors were significantly, although weakly, correlated (r = 13; P < .001) and few respondents (31.3%) scored high on both indices. OLS regression on a combined index of oral and general health behaviors found that females, older respondents, and those with higher incomes were more likely to engage in a higher level of health behaviors. CONCLUSIONS: These results indicate the need to develop health promotion life style programs that incorporate both dental and general health components and to target these programs to younger age groups, males, and those with low incomes.

Escherichia coli O157:H7 restriction pattern recognition by artificial neural network.

An artificial neural network model for the recognition of Escherichia coli O157:H7 restriction patterns was designed. In the training phase, images of two classes of E. coli isolates (O157:H7 and non-O157:H7) were digitized and transmitted to the neural network. The system was then tested for recognition of images not included in the training set. Promising results were achieved with the designed network configuration, providing a basis for further study. This application of a new generation of computation technology serves as an example of its usefulness in microbiology.

Pharmacokinetic, pharmacodynamic, and pharmacotoxic profiles of recombinant-methionyl human interleukin-2[alanine-125] (r-metHuIL-2[ala-125]) following intravenous and subcutaneous administration in rats.

Comparative pharmacotoxicity studies in rats were performed to evaluate the response to r-metHuIL-2[ala-125] following 2 or 4 weeks of daily intravenous or subcutaneous administration, as well as to evaluate pharmacokinetic and pharmacodynamic responses. Pharmacokinetic analysis indicated that r-metHuIL-2[ala-125] showed high bioavailability and nonlinear concentration profiles. Pharmacodynamic responses to intravenous or subcutaneous dosing with r-metHuIL-2[ala-125], as measured by white blood cell counts, were comparable. Preclinical safety studies (6, 30, and 150 micrograms kg-1 day-1) indicated that r-metHuIL-2[ala-125], whether given intravenously or subcutaneously, was associated with increased circulating and infiltrating levels of lymphocytes and eosinophils. Bone marrow lymphoid hyperplasia and splenic extramedullary hematopoiesis were similarly observed in each study. This pattern of effects was considered an exaggerated pharmacodynamic response to r-metHuIL-2[ala-125]. Of further note was a histopathologic finding described as hepatocyte single cell necrosis which was observed following both intravenous and subcutaneous administration and was considered to be a toxic response to high doses of r-metHuIL-2[ala-125]. The no observable adverse effect level (NOAEL) for r-metHuIL-2[ala-125] via intravenous administration was 6 micrograms kg-1 day-1, while that for subcutaneous administration was 30 micrograms kg-1 day-1. Data herein present a form of rHuIL-2 with pharmacokinetic and pharmacodynamic profiles that are similar when given by these two systemic routes. Pharmacotoxic data, based on NOAELs, suggest that subcutaneous administration may be a preferred clinical route of administration.

Preventive oral health behaviors in a multi-cultural population: the North York Oral Health Promotion Survey.

To examine the preventive oral health behavior levels of randomly-selected dentate and edentulous adults, age 18 and over, a mail survey was conducted in North York, Ontario, a multicultural suburb of Metropolitan Toronto (n = 1,050). High optimal levels of at least daily tooth brushing were reported by the majority of the dentate (96 per cent). Lower rates were evident for yearly preventive visiting (69 per cent), daily flossing (22 per cent), daily use of an interdental device (25 per cent), not snacking between meals (12 per cent) and eating one or no cariogenic foods on the previous day (36 per cent). Logistic regression results indicated higher levels on an additive index of oral preventive behaviors for females, those having a higher education and non-Italian respondents. Edentulous respondents reported high daily denture cleaning rates (87 per cent), but less frequent night removal (51 per cent), checking for oral lesions (68 per cent) and preventive visiting (12 per cent). Oral disease is one of the most common and costly chronic disorders affecting modern populations. However, unlike most other chronic diseases, it is largely preventable. These data indicate a clear need for determined oral health promotion efforts to inform and encourage increased levels of preventive behaviors in addition to tooth and denture brushing, particularly among specific sociodemographic and ethnic groups.

Pertussis in Missouri: evaluation of nasopharyngeal culture, direct fluorescent antibody testing, and clinical case definitions in the diagnosis of pertussis.

No diagnostic test for pertussis in routine use in the United States has both high sensitivity and high specificity. During a statewide increase in the incidence of pertussis in Missouri, we studied the clinical features of 153 patients with suspected pertussis in the Greater St. Louis area from whom a specimen for pertussis culture had been taken between 15 May and 19 September 1989. In this cross-sectional study, nasopharyngeal cultures were more likely to be positive for persons whose specimens were collected < 21 days after cough onset (adjusted rate ratio [RRa] and 95% confidence interval = 3.4; 1.5-8.0) and who were not receiving erythromycin/sulfamethoxazole prior to the culture [RRa = 5.8; 0.8-40.6], who had received fewer than three prior doses of pertussis vaccine [RRa = 1.8; 0.8-4.2], and whose specimen was in transit to the laboratory for < 4 days [RRa = 2.0; 0.8-5.5]. Among children < 5 years of age, spasmodic cough plus a lymphocytosis of > 10,000/mm3 was the acute symptom complex associated with the highest predictive value for a positive culture result (67%). Cough for > or = 14 days plus whoop was sensitive (81%) and specific (58%) for identifying children with culture-confirmed pertussis. Direct fluorescent antibody staining performed well as a screening test for pertussis but requires substantial commitment of personnel and resources. In the absence of a positive culture result, clinical case definitions should be used for decision making (e.g., initiation of antimicrobial therapy and routine case reporting).

Tamoxifen induces hepatocellular carcinoma in rat liver: a 1-year study with two antiestrogens.

The effects of equimolar doses of the triphenylethylene antiestrogens tamoxifen and toremifene on female Sprague-Dawley rat liver were studied in a 52-week toxicity study which included a 13-week recovery period. Liver tumors were found in four out of five rats at the highest dose level of tamoxifen (45 mg/kg per day) after 52 weeks of dosing, and these appeared to be hepatocellular carcinomas in three rats. After the 13-week recovery period all surviving rats in the highest tamoxifen dose group had large liver tumors (diameter up to 2 cm) which appeared to be hepatocellular carcinomas in five out of six rats. No tumor was observed in the toremifene-treated rats (48 mg/kg per day) either after 52 weeks of dosing or after the recovery period. Electron microscopic morphometric analysis after 52 weeks of dosing revealed that at the tamoxifen high dose level, the volume densities of the peroxisomes, mitochondria, and residual bodies were elevated in the nonneoplastic hepatocytes of the rats. In the neoplastic hepatocytes of the tamoxifen-treated rats the volume density of nuclei was slightly elevated. The slight proliferation of peroxisomes and mitochondria might be related to tumor development in the tamoxifen treated rats.

Oral self-care behaviours in older dentate adults.

Defining oral self-care as activities undertaken by individuals to maintain or promote dental health, this paper examines the distribution of oral self-care behaviours in a sample of dentate adults, age 50 and over, living in Ontario, Canada (n = 713). Results are presented separately for two older cohorts, respondents ages 50-64 and those 65 and older, and for females and males. Six oral self-care behaviours were examined: toothbrushing, flossing, use of an interdental device, extra fluoride use, frequency of between meal snacks and ingestion of cariogenic foods. High rates of self-care occurred only for toothbrushing. Age groups differed significantly for use of interdental devices, consumption of cariogenic foods and snacking between meals while gender differences were found for toothbrushing, flossing and consuming sweet foods. The need to target older adults and especially older males for oral hygiene information and instruction in order to counteract possible misleading beliefs learned before the advent of current dental hygiene practices is apparent from these data.

A waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody diarrhea and death.

OBJECTIVE: To describe and determine the source of a large outbreak of Escherichia coli O157:H7 (ECO157) infections in Missouri. DESIGN: A case-control study and a household survey. SETTING: A small city in a rural Missouri township that had an unchlorinated water supply. PATIENTS: Case patients were residents of or visitors to Burdine Township with bloody diarrhea or diarrhea and abdominal cramps occurring between 15 December 1989 and 20 January 1990. MEASUREMENTS: Escherichia coli O157 was isolated from 21 stool specimens. All isolates were resistant to sulfisoxazole, tetracycline, and streptomycin; produced Shiga-like toxins I and II; and had one 60-megadalton plasmid. RESULTS: Among the 243 case patients, 86 had bloody stools, 32 were hospitalized, 4 died, and 2 had the hemolytic uremic syndrome. In the case-control study, no food was associated with illness, but ill persons had drunk more municipal water than had controls (P = 0.04). The survey showed that, during the peak of the outbreak, bloody diarrhea was 18.2 times more likely to occur in persons living inside the city and using municipal water than in persons living outside the city and using private well water (P = 0.001). Shortly before the peak of the outbreak, 45 water meters were replaced, and two water mains ruptured. The number of new cases declined rapidly after residents were ordered to boil water and after chlorination of the water supply. CONCLUSIONS: This was the largest outbreak of ECO157 infections, the first due to a multiply resistant organism, and the first shown to be transmitted by water. System-wide chlorination as well as hyperchlorination during repairs might have prevented this outbreak. Both bloody and nonbloody diarrhea may be common manifestations of this infection, which is probably underdiagnosed because of the failure of routine stool cultures to identify the organism. Cities with deteriorating water systems using untreated water risk widespread illness from contaminated drinking water.

Carcinogenicity study of auranofin, an orally administered gold compound, in mice.

Auranofin, a gold-containing compound, was administered to Charles River CD-1 mice for 18 months to assess its possible carcinogenicity. The mice were dosed orally with 1.0, 3.0, or 6.0 (increased to 9.0 on Day 294) mg/kg/day. Each dose group and each of two control groups contained 110 males and 110 females. Survival was greater than 70% at the end of the study. No effect of the treatment on neoplastic or nonneoplastic lesions was found. This is in contrast to the results reported in rats. Auranofin in rats produced a heavy metal nephropathy characterized by acute coagulative necrosis, subacute renal cortical fibrosis, chronic cytomegaly and karyomegaly, and finally renal cortical neoplasia (adenomas and adenocarcinomas). The lack of effect of auranofin on tumor incidence in mice suggests the findings in rats may be species specific.

Person-to-person transmission in an outbreak of enteroinvasive Escherichia coli.

In the summer of 1981, an outbreak of diarrhea occurred in students and staff at a school for mentally retarded adults and children in Columbia, Missouri. Forty-one (48%) of 86 students and 38 (28%) of 137 staff members in the two dormitories with the lowest functioning students were ill. Enteroinvasive Escherichia coli 0124:H30 was isolated from 20 persons including six staff members, 13 students, and the ill mother of one of the students. Contact with students was associated with illness. Thirty-eight (33%) of the 115 student-care staff members and none of the 22 nonstudent-care staff members who worked in the two dormitories were ill (p = 0.004, chi-square). In the dormitory with the most dependent students, illness in student-care staff was associated with the number of contacts with ill students and with having taken a student home during the outbreak. Control measures to interrupt transmission included separation of symptomatic or culture-positive students from those who were well, and emphasizing handwashing. The authors present these findings as the first report of person-to-person transmission in an outbreak of enteroinvasive E. coli.