Does wearing a functional knee brace affect hamstring reflex time in subjects with anterior cruciate ligament deficiency during muscle fatigue?

OBJECTIVE: To evaluate the effects of wearing a functional knee brace and muscle fatigue on hamstring reflex time in subjects with anterior cruciate ligament (ACL) deficiency. DESIGN: Repeated-measures clinical trial. SETTING: Outpatient physical therapy department. PARTICIPANTS: Sixteen subjects with ACL deficiency. INTERVENTION: Subjects tested with and without a functional knee brace before and after an exercise protocol designed to fatigue the knee muscles. MAIN OUTCOME MEASURE: Latency of hamstring reflex muscle activity after sudden perturbation of the knee. RESULTS: Wearing a knee brace shortened the hamstring reflex latency regardless of fatigue (F(1,15)=20.62, P<.001). Muscle fatigue lengthened the hamstring reflex time regardless of the bracing condition (F(1,15)=7.57, P<.015). CONCLUSION: Wearing a functional knee brace facilitated hamstring muscle reflex, but muscle fatigue lengthened the hamstring reflex latency. Subjects with ACL deficiency should not rely on the knee brace to facilitate hamstring reflex for joint protection during prolonged sporting activities when muscles are fatigued.     

GATA-1 as a regulator of mast cell differentiation revealed by the phenotype of the GATA-1low mouse mutant

Here it is shown that the phenotype of adult mice lacking the first enhancer (DNA hypersensitive site I) and the distal promoter of the GATA-1 gene (neo Delta HS or GATA-1(low) mutants) reveals defects in mast cell development. These include the presence of morphologically abnormal alcian blue(+) mast cells and apoptotic metachromatic(-) mast cell precursors in connective tissues and peritoneal lavage and numerous (60-70% of all the progenitors) "unique" trilineage cells committed to erythroid, megakaryocytic, and mast pathways in the bone marrow and spleen. These abnormalities, which were mirrored by impaired mast differentiation in vitro, were reversed by retroviral-mediated expression of GATA-1 cDNA. These data indicate an essential role for GATA-1 in mast cell differentiation.     

Molecular Cloning and Functional Analysis of a Novel Tetracycline Resistance Determinant, tet(V), from Mycobacterium smegmatis

The nucleotide sequence and mechanism of action of a tetracycline resistance gene from Mycobacterium smegmatis were determined. Analysis of a 2.2-kb sequence fragment showed the presence of one open reading frame, designated tet(V), encoding a 419-amino-acid protein (molecular weight, 44,610) with at least 10 transmembrane domains. A database search showed that the gene is homologous to membrane-associated antibiotic efflux pump proteins but not to any known tetracycline efflux pumps. The steady-state accumulation level of tetracycline by M. smegmatis harboring a plasmid carrying the tet(V) gene was about fourfold lower than that of the parental strain. Furthermore, the energy uncoupler carbonyl cyanide m-chlorophenylhydrazone blocked tetracycline efflux in deenergized cells. These results suggest that the tet(V) gene codes for a drug antiporter which uses the proton motive force for the active efflux of tetracycline. By primer-specific amplification the gene appears to be restricted to M. smegmatis and M. fortuitum.     

Non-radioactive gene probes for the detection of tetracycline and/or minocycline resistance in staphylococci

This report describes the development of a non-radioactive gene probe for the characterization of tetracycline and/or minocycline resistant staphylococci. Both radio-labelled and non-radioactive gene probes yielded a better characterization of the strains than the determination of minimal inhibitory concentration (MIC). A 100% correlation was found between radioactive and non-radioactive hybridization tests. The latter technique detected genes present in a single copy per bacterial genome, could be performed in 8 h, avoided radioactive hazards and autoradiography delay, and appeared therefore to be a useful tool for clinical and epidemiological studies.     

Beyond caring

"Can caring be taught?" is a question that spurs an emotional debate among nurses and leads to further questions: Is nursing science overshadowed by caring in nursing practice? Is the scientific basis of the nursing profession overlooked as a result of the emphasis of caring in nursing? Is it a logical fallacy to assume a correlation between nursing science and caring? Can nursing science or caring alone provide the basis of nursing practice? Further investigation is necessary into the depth of caring and its impact on nursing science and practice.     

ELECTRON MICROSCOPY OF IN VITRO ENDOCYTOSIS OF T2 PHAGE BY CELLS FROM RABBIT PERITONEAL EXUDATE

Macrophages from rabbit peritoneal exudate cells incubated in vitro with T₂ bacteriophage from 10 up to 120 minutes show phage particles adsorbed to cell membranes, in the process of being engulfed by means of rhopheocytosis, micropinocytosis, and phagocytosis, and localized within dense vacuoles, semi-dense vacuoles, and clear vacuoles of the cytoplasm. The electronmicrographs suggest that newly formed endocytic vacuoles containing phage particles fuse with one another and also fuse with dense bodies of the cytoplasm as they migrate towards the cell interior, thus yielding larger vacuoles of varying densities containing higher concentrations of phage. The polymorphonuclear cells present in a small proportion in the peritoneal exudate cells also endocytosed phage particles. The T₂ particles are found in large cytoplasmic vacuoles surrounded by an electron-opaque material presumably derived from cytoplasmic granules. No disintegration of T₂ phage within the macrophage following incubations up to 120 minutes could be demonstrated; however, disrupted phage particles were noted within cytoplasmic vacuoles of polymorphonuclear leucocytes after 15 minutes' incubation.     

Vasoactive peptides in cardiovascular (patho)physiology

Numerous vasoactive agents play an important physiological role in regulating vascular tone, reactivity and structure. In pathological conditions, alterations in the regulation of vasoactive peptides result in endothelial dysfunction, vascular remodeling and vascular inflammation, which are important processes underlying vascular damage in cardiovascular disease. Among the many vasoactive agents implicated in vascular (patho)biology, angiotensin II (Ang II), endothelin (ET), serotonin and natriuretic peptides appear to be particularly important because of their many pleiotropic actions and because they have been identified as potential therapeutic targets in cardiovascular disease. Ang II, ET-1, serotonin and natriuretic peptides mediate effects via specific receptors, which belong to the group of G-protein-coupled receptors. ET, serotonin and Ang II are primarily vasoconstrictors with growth-promoting actions, whereas natriuretic peptides, specifically atrial, brain and C-type natriuretic peptides, are vasodilators with natriuretic effects. Inhibition of vasoconstrictor actions with drugs that block peptide receptors, compounds that inhibit enzymes that generate vasoactive peptides or agents that increase levels of natriuretic peptides are potentially valuable therapeutic tools in the management of cardiovascular diseases. This review focuses on ET, natriuretic peptides and serotonin. The properties and distribution of these vasoactive agents and their receptors, mechanisms of action and implications in cardiovascular (patho)physiology will be discussed.     

Sacral examination in spinal cord injury: Is it really needed?

Objective: To determine if a self-report measure of S4-5 motor and sensory function in patients with chronic SCI accurately predicts sacral examination results.

Design: Prospective, single-blinded self-report survey compared with sacral exam.

Setting: Outpatient SCI clinic.

Participants: 116 patients aged 18+ with chronic SCI > 6 months who have undergone sacral exam.

Interventions: The survey included demographic/clinical and sacral function information such as light tough (LT), pinprick sensation (PP), deep anal pressure (DAP) and voluntary anal contraction (VAC). Survey results and sacral exam were compared and stratified by the patient’s American Spinal Cord Injury Association Impairment Scale (AIS) category.

Outcome Measures: Sacral self-report survey, AIS examination.

Results: Mean age was 41.3?±?14.4 years with majority male (69%) and Caucasian (71.6%). Overall, Positive Predictive Value (PPV) ranged between 48% (VAC) to 73% (DAP) and Negative Predictive Value (NPV) between 92% (VAC) to 100% (LT). AIS-A had NPV of 100% across all categories, and AIS-D had PPV of 100% across all categories.

Conclusion: Patient report of sacral sparing can predict negative sensation in patients with AIS-A and predict positive sensation in persons with AIS-D. Overall, the self-report of sacral sparing of motor and sensory function is not predictive enough to rely on for accurate classification.     

B-1a B cells that link the innate and adaptive immune responses are lacking in the absence of the spleen

Splenectomized individuals are prone to overwhelming infections with encapsulated bacteria and splenectomy of mice increases susceptibility to streptococcal infections, yet the exact mechanism by which the spleen protects against such infections is unknown. Using congenitally asplenic mice as a model, we show that the spleen is essential for the generation of B-1a cells, a B cell population that cooperates with the innate immune system to control early bacterial and viral growth. Splenectomy of wild-type mice further demonstrated that the spleen is also important for the survival of B-1a cells. Transfer experiments demonstrate that lack of these cells, as opposed to the absence of the spleen per se, is associated with an inability to mount a rapid immune response against streptococcal polysaccharides. Thus, absence of the spleen and the associated increased susceptibility to streptococcal infections is correlated with lack of B-1a B cells. These findings reveal a hitherto unknown role of the spleen in generating and maintaining the B-1a B cell pool.     

The role of biobehavioral, environmental, and social forces on oral health disparities in frail and functionally dependent nursing home elders

The purpose of this article is to review the literature on and discuss how interactions between bio-behavioral aging, nursing home environments, and social forces shaping current health care policies have contributed to oral health disparities in frail and functionally dependent elders who reside in nursing homes. Emerging empirical evidence suggests links between poor oral health with dental plaque deposition and systemic disease, such as nursing home-acquired pneumonia. The majority of nursing home residents lack either the functional ability or the mental capacity to perform their own mouth care and therefore must rely on others to perform mouth care for them. Certified nursing assistants (CNAs), who provide the majority of care activities, were unsure how to provide care to residents who engaged in care-resistive behaviors. The nurses who supervise the CNAs have limited knowledge regarding the provision of mouth care in general, and they specifically lack knowledge regarding the provision of mouth care to elders exhibiting care-resistant behavior. Elders in nursing homes have limited options when paying for dental care; Medicare does not generally cover routine dental care. Medicaid coverage varies widely between individual states; even when coverage exists, low Medicaid reimbursements discourage dentists from accepting Medicaid patients. The strategies needed to reduce these oral health disparities are complicated but not unrealistic. Investigators willing to embrace this cause will have no shortage of opportunities to test methods to improve the delivery of oral care as well as to monitor and reassess these methods.