The mammary pathology of genetically engineered mice: the consensus report and recommendations from the Annapolis meeting

NIH sponsored a meeting of medical and veterinary pathologists with mammary gland expertise in Annapolis in March 1999. Rapid development of mouse mammary models has accentuated the need for definitions of the mammary lesions in genetically engineered mice (GEM) and to assess their usefulness as models of human breast disease. The panel of nine pathologists independently reviewed material representing over 90% of the published systems. The GEM tumors were found to have: (1) phenotypes similar to those of non-GEM; (2) signature phenotypes specific to the transgene; and (3) some morphological similarities to the human disease. The current mouse mammary and human breast tumor classifications describe the majority of GEM lesions but unique morphologic lesions are found in many GEM. Since little information is available on the natural history of GEM lesions, a simple morphologic nomenclature is proposed that allows direct comparisons between models. Future progress requires rigorous application of guidelines covering pathologic examination of the mammary gland and the whole animal. Since the phenotype of the lesions is an essential component of their molecular pathology, funding agencies should adopt policies ensuring careful morphological evaluation of any funded research involving animal models. A pathologist should be part of each research team.     

Education and training of healthcare staff: the barriers to its success

On-going developments in Britain's healthcare services are placing great demands on its workforce. If high quality care is to be maintained, education and training is needed to provide staff with the necessary knowledge and skills to adapt to their changing roles. A recent research project looking at the education and training needs of non-specialist staff caring for people with cancer identified a number of barriers that prevent education and training from meeting its full potential. These barriers include time, accessibility, financial issues, staff motivation and marketing and advertising and are discussed in this paper together with some possible solutions to overcome them. It is concluded that the planning and development of education and training must address these barriers if it is to be successful in increasing the knowledge and skills of staff, and thereby improve the quality of patient care.     

Dipeptidyl(amino)peptidase IV and aminopeptidase M metabolize circulating substance P in vivo.

Recent studies have demonstrated that Fischer-344 rats from Japanese Charles River Inc. specifically lack dipeptidyl(amino)peptidase IV (DAP IV-negative; EC 3.4.14.5), whereas Fischer-344 rats from sources within the United States (DAP IV-positive) possess normal DAP IV activity. In the present study, plasma from DAP IV-positive rats metabolized substance P (SP) (5.37 +/- 0.25 nmol/min/ml) via the actions of angiotensin-converting enzyme (EC 3.4.15.1) (1.86 +/- 0.50 nmol/min/ml) and DAP IV (2.56 +/- 0.42 nmol/min/ml). DAP IV sequentially converted SP to SP[3-11] and SP[5-11]. The SP[5-11] metabolite was then rapidly hydrolyzed by plasma aminopeptidase M (AmM; EC 3.4.11.2) (36.2 +/- 4.2 nmol/min/ml). In contrast, SP metabolism by plasma from DAP IV-negative rats was less than half that of control animals (2.14 +/- 0.06 nmol/min/ml), due to a complete lack of DAP IV hydrolysis. The absence of DAP IV was not associated with any differences in angiotensin-converting enzyme-mediated hydrolysis of SP (1.45 +/- 0.11 nmol/min/ml) or AmM-mediated hydrolysis of SP[5-11] (37.1 +/- 0.9 nmol/min/ml). Consistent with this deficiency in SP metabolism, SP was more potent in vivo in stimulating salivary secretion in DAP IV-negative rats compared to DAP IV-positive animals. Potentiation was specific in that SP[5-11], an SP fragment resistant to DAP IV, was equipotent in DAP IV-negative and positive animals. SP[5-11]-induced salivary secretion was potentiated in both strains when AmM-mediated hydrolysis was inhibited by amastatin (20 nmol/min, i.v.). These data provide direct evidence for a significant role for DAP IV and AmM in the in vivo processing of SP and active SP metabolites.     

Papillary immature metaplasia of the cervix: a distinct subset of exophytic cervical condyloma associated with HPV-6/11 nucleic acids.

A subset of exophytic cervical precursor lesions are composed of immature metaplastic cells that differ from conventional condylomata by the virtual absence of koilocytotic atypia and the presence of slender filiform papillae. We evaluated a series of exophytic cervical lesions containing this morphology for HPV nucleic acids and compared the associated HPV types with conventional exophytic condylomata of the cervix. Six of six exophytic condylomata and five of six papillary immature metaplasias (PIM), respectively, contained HPV type 6/11 by in situ hybridization. Subtyping of three PIM by polymerase chain reaction combined with direct sequencing revealed nucleic acid sequences consistent with HPV 6/11. PIM were distinguished from high-grade squamous intraepithelial lesions by the rarity of mitoses and by the uniformity of nuclear size and staining intensity with multiple chromocenters. However, these lesions tended to involve the more cephalad region of the cervical transformation zone, and three cases extended deeply into the endocervix with two requiring conization for a definitive diagnosis. Although their bland morphology and association with HPV 6/11 nucleic acids suggest a benign process, their location within the endocervical canal implies that these variants of condyloma may differ biologically from conventional exophytic condylomas of the cervix. The differential diagnosis of PIM and potential explanations for their distinctive morphology, are discussed.     

Antimicrobial therapy for methicillin-resistant Staphylococcus aureus colonization in residents and staff of a Veterans Affairs nursing home care unit.

OBJECTIVE: To evaluate the effect of antimicrobial therapy on patients and staff colonized with methicillin-resistant Staphylococcus aureus (MRSA) in a skilled nursing facility and to assess the role of the environment as a potential reservoir for MRSA in the nursing home setting. DESIGN: As part of a comprehensive program to control an MRSA outbreak in a nursing home, patients and staff colonized with MRSA received 1 of 3 antimicrobial decolonization regimens depending upon the site and extent of colonization. Followup cultures were performed during therapy and on days 2, 7, 14, and 30 following the completion of therapy. Cultures of the patients' inanimate environment (pajamas, sheet, and floor) were obtained during and after therapy. Antimicrobial susceptibility tests were performed on 54 MRSA isolates obtained before and 44 MRSA isolates recovered after therapy. SETTING: A 120-bed Veterans Affairs nursing home care unit. PARTICIPANTS: Thirty-six patients and 7 staff nurses colonized with MRSA at 1 or more sites. INTERVENTION: Decolonization therapy with rifampin, trimethoprim-sulfamethoxazole, and clindamycin used alone or in various combinations for 5 or 10 days in conjunction with other infection control measures employed to combat the MRSA outbreak. RESULTS: Twenty (56%) of the 36 NHCU patients were either persistently colonized or became recolonized with MRSA during the 30-day followup period. Positive cultures on day 3 during therapy frequently identified patients who subsequently exhibited persistent or recurrent colonization. Before therapy, 92% of MRSA isolates were susceptible to rifampin, whereas only 43% of the isolates obtained after therapy were susceptible. Sixteen (80%) of 20 patients with persistent or recurrent colonization had rifampin-resistant strains of MRSA isolated after therapy. Twenty-three (18%) of 125 environmental cultures obtained during and after therapy from patients who exhibited persistent or recurrent colonization were positive for MRSA, in contrast to 9 (8%) of 107 from patients who were successfully decolonized. CONCLUSIONS: The decolonization component of the outbreak control program was judged to be ineffective and potentially hazardous because colonization persisted or recurred in more than half of the patients, and substantial antimicrobial resistance was noted in MRSA stains isolated after therapy. Resistance, especially to rifampin, and possibly re-acquisition of MRSA from other human or environmental sources were 2 factors that appeared to impede the decolonization effort.     

Expression ofNeisseria meningitidisclass 1 porin as a fusion protein inEscherichia colli: the influence of liposomes and adjuvants on the production of a bactericidal immune reesponse

High level exxpression of meningococcal class 1 protein was achieved inEscherichia coliusing the p-GEMEX-1 vector, in which the protein was expressed in inclusion bodies, (IB), as a fusion with the bacteriophage T7 gene 10 capsid protein. The fusion protein (FP) was engineered with a factor Xa protease site between the gene 10 and class 1 protein, but treatment with the enzyme resulted in cleavage at additional sites within the class 1 protein. Since it was not possible to remove the leader protein, the intact FP provided an alternative antigen for immunization. Antisera raised to FP, solubilized from IB and incorporated into liposomes, generated a subtype-specific response which was weakly bactericidal for meningococci. In order to remove any possible effect ofE. coliLPS present in IB, the FP was further purified by SDS-PAGE and incorporated into liposomes, either alone ofr in combination with the adjuvants monophosphoryl lipin A or muramyl dipeptide. The incorporation of adjuvants in liposomes resulted in stimulation of the overall immune response to FP, but the resulting antisera were not bactericidal. however and effective bactericidal response was obtained with the purest preparation of FP in liposomes, without any additional adjuvants, revealing that attempts to increase further the immunogenicity of such antigens must not be at the expense of interfering with optimal protein folding