Schistosome invasion of human skin and degradation of dermal elastin are mediated by a single serine protease.

Aquatic larvae (cercariae) of the trematode parasite Schistosoma mansoni rapidly penetrate human skin by degrading host proteins including elastin. Two serine proteases, one chymotrypsin-like and the second trypsin-like, have been proposed to be involved. To evaluate the relative roles of these two proteases in larval invasion, both were purified, identified by sequence, and then biochemically characterized. The trypsin-like activity was resolved into two distinct serine proteases 76% similar in predicted amino acid sequence. Southern blot analysis, genomic polymerase chain reaction, and immunolocalization demonstrated that the trypsin-like proteases are in fact not from the schistosome, but are released with larvae from the snail host Biomphalaria glabrata. Invasion inhibition assays using selective inhibitors confirmed that the chymotrypsin-like protease is the enzyme involved in skin penetration. Its ability to degrade skin elastin was confirmed, and the three sites of cleavage within elastin help define a new family of elastases.

Identification of a cDNA encoding an active asparaginyl endopeptidase of Schistosoma mansoni and its expression in Pichia pastoris.

Asparaginyl endopeptidases, or legumains, are a recently identified family of cysteine-class endopeptidases. A single gene encoding a Schistosoma mansoni asparaginyl endopeptidase (a.k.a. Sm32 or schistosome legumain) has been reported, but by sequence homology it would be expected to yield an inactive product as the active site C197 had been replaced by N. We now describe a new S. mansoni gene in which C197 is present. Both gene products were expressed in Pichia pastoris. Autocatalytic processing to fully active C197 Sm32 occurred at acid pH. In contrast, N197 Sm32 was not processed and this is consistent with the hypothesis that C197 is essential for catalysis. This was confirmed by mutation of N197 to C and re-expression in Pichia. The availability of recombinant active Sm32 allows detailed analysis of its catalytic mechanism and its function(s) in the biology of this important human parasite.

Stop and look: two approaches to manage stroke patients.

Two to three million people in this country live with the after-effects of a stroke. Care focuses on increasing the functional abilities of the stroke patient. Currently, there are different approaches used in caring for the stroke patient. Two approaches are presented for consideration in working with the stroke patient. A case study illustrates differences between the two approaches. Regardless of the approach used, consistency and long-term goal setting is necessary for patient progress.

A model for professional rehabilitation nursing practice.

As partners in health care, clinical and administrative nurses must share in the work, risks, and rewards inherent in nursing practice while promoting high-quality results in a cost-conscious and cost-effective environment. One way to achieve these results is by developing a nontraditional rehabilitation structure and nursing practice model. This article discusses practical strategies for constructing and implementing such a model; it also identifies tangible outcomes of using the model. The healthcare environment in the 1990s demands a high level of involvement on the part of staff; the rehabilitation nursing model presented in this article meets this challenge.

Geriatric falls: prevention strategies for the staff.

1. Multiple falls and injuries are more prevalent among elderly over the age of 75 and are the second leading cause of accidental death in the elderly. The risk for falling is noted to be significantly greater in the hospitalized elderly. 2. Review of retrospective quality improvement chart audits revealed that peak fall times were associated with the patient's need for toileting, rest, and obtaining nutrition and hydration. 3. The MetroHealth Falls Prevention Program is based on simple proactive measures to prevent falls in the elderly. 4. An effective falls prevention program has several implications for gerontological nursing practice, including less restraint use, increased patient autonomy, and decreased loss of self-esteem. There is also a sense of increased nursing control over patient safety and time management, as well as implications for further nursing research.

Urinary tract infections: a quality assurance rehabilitation nursing perspective.

This article describes a quality assurance study related to urinary tract infections at the Great Lakes Regional Rehabilitation Center, Lorain Community Hospital, Lorain, OH. A literature review, methods, and study results are presented. Four practical strategies to deal with urinary tract infections are delineated.