Zebrafish (Danio rerio) as a screen for attenuation of Lancefield group C streptococci and a model for streptococcal pathogenesis.

Group C streptococci are highly contagious pyogenic bacteria responsible for respiratory tract, lymph node, urogenital tract, and wound infections. Wild-type strains of Streptococcus equi ssp equi (S. equi) and Streptococcus equi ssp zooepidemicus (S. zoo) as well as a commercially available modified live vaccine strain of S. equi were evaluated for virulence in zebrafish. Survival times, histologic lesions, and relative gene expression were compared among groups. Based on the intramuscular route of infection, significantly shorter survival times were observed in fish infected with wild-type strain when compared to modified live vaccine and S. zoo strains. Histologically, S. zoo-infected fish demonstrated a marked increase in inflammatory infiltrates (predominantly macrophages) at the site of infection, as well as increased cellularity in the spleen and renal interstitium. In contrast, minimal cellular immune response was observed in S. equi-injected fish with local tissue necrosis and edema predominating. Based on whole comparative genomic hybridization, increased transcription of positive acute-phase proteins, coagulation factors, and antimicrobial peptides were observed in S. equi-injected fish relative to S. zoo-injected fish, while mediators of cellular inflammation, including CXC chemokines and granulin, were upregulated in S. zoo-injected fish relative to S. equi-injected fish. In a screen of 11 clinical isolates, S. equi strains with a single nucleotide deletion in the upstream region of szp, a known virulence factor of streptococci, were found to be significantly attenuated in zebrafish. These collective findings underscore the value of the zebrafish as a model of streptococcal pathogenesis.

Mammographic appearance of breast cancer in African-American women: report of 100 consecutive cases.

RATIONALE AND OBJECTIVES: The authors determined the mammographic appearance of breast carcinoma in African-American women and compared it with that in a white cohort. MATERIALS AND METHODS: The authors reviewed the mammograms, clinical records, and pathology records of 97 consecutive African-American women with 100 confirmed breast cancers and 110 white women with 111 confirmed breast cancers. RESULTS: The mammograms obtained in African-American women were positive in 94 cases (94%), and those obtained in white women were positive in 99 cases (89%). Forty-seven percent of malignancies in African-American women appeared as calcifications, alone or with a mass, and 41% appeared as a mass only. There was no statistically significant difference in the frequency of these two findings between the African-American and the white populations. There was no statistically significant difference in the breast parenchymal pattern between the two groups. The most common tumor location in both races was the upper outer quadrant. CONCLUSION: Breast carcinoma in African-American women is similar to that in white women in terms of mammographic appearance, location, and breast density. The mammographic appearance should not be an impediment to the detection of breast cancer in African-American women.

Priorities for continuing education courses.

A mail questionnaire on continuing education was sent out to all dentists in Alberta and Atlantic Canada. A total of 415 completed questionnaires were received from Alberta dentists, while the response from Atlantic Canada was 235. A significant majority of the dentists indicated that continuing education was important to them. Those who thought that continuing education was important tended to be more supportive of mandatory continuing education. October is the month that is preferred for courses. In Atlantic Canada, November was the second choice, while February was second in Alberta. The three most significant factors in the selection of a continuing education course in order of importance were: course content, course speaker and location.

Adaptation of a stable L-form of Bacillus subtilis to minimal salts medium without osmotic stabilizers.

An L-form isolated from Bacillus subtilis 168 was adapted to growth in a 340 mOsm minimal salts medium without the addition of osmotically protective solutes. This L-form had no chemically detectable peptidoglycan residues on its surface, but 0.8% of the dry weight of washed membranes was hexosamine. The osmotic stability and susceptibility to bacitracin and vancomycin of the L-form adapted to growth in 340 mOsm osmotically unprotected medium was twice that of the L-form grown in 2,680 mOsm medium supplemented with 1.2 M NaCl.

Quantitation of bacillus subtilis L-form growth parameters in batch culture.

Several methods were used to monitor the growth of a stable L-form in batch culture. The end of the exponential growth phase was determined with greatest accuracy by the amounts of deoxyribonucleic acid per milliliter of culture. Optical density and viable count data were not as reliable because the L-forms began to lyse at the end of exponential growth. Lysis was detected visually, by phase-contrast observations of wet mounts, and by release of ultraviolet-absorbing material into culture supernatant fluids.

Stones and infection in renal caliceal diverticula: treatment with percutaneous procedures.

Percutaneous treatment of symptomatic caliceal diverticula has expanded the application of uroradiologic intervention. To assess the safety and efficacy of these procedures, we have reviewed our experience with percutaneous management of 12 symptomatic caliceal diverticula, 10 with stones and two infected. Nine stone-bearing diverticula were punctured directly with subsequent tract dilatation, nephroscopic stone extraction, and cavity obliteration (six with fulguration and drainage and three with drainage alone). One case was approached indirectly by puncturing a distant calix, dilating the diverticular neck, and flushing the stones into the collecting system for extraction. This cavity was not treated. Two infected diverticula were punctured directly for drainage and obliteration (one by fulguration and one by tetracycline sclerosis). Complete stone extractions were accomplished in all 10 cases. In eight with clinical follow-up ranging from 4 months to 6 years, one stone has recurred and seven patients are asymptomatic. Follow-up urograms were available in eight of 10 patients in whom cavity obliteration was attempted; in six (75%) of eight, nonvisualization of the diverticulum indicated successful obliteration. Only one major complication (urinoma requiring drainage) occurred. We conclude that percutaneous procedures are safe and effective in treating infected or stone-bearing caliceal diverticula. Direct diverticular puncture for access and diverticular fulguration for cavity obliteration is our preferred technique.

Metaplastic carcinoma of the breast: mammographic appearance with pathologic correlation.

OBJECTIVE: The objective of this study was to describe the mammographic appearance with pathologic correlation of metaplastic carcinoma of the breast. CONCLUSION: Metaplastic carcinomas of the breast are masses with mammographic characteristics of low suspicion because of their histologic appearance. Metaplastic carcinoma should be included in the differential assessment of predominately circumscribed, noncalcified masses revealed on mammography. One salient feature that may distinguish metaplastic carcinomas is the occurrence of a circumscribed portion with a spiculated portion, which is seen in carcinomas that have a significant mixture of metaplastic and invasive carcinoma growth patterns.