The effect of a critical care outreach service and an early warning scoring system on respiratory rate recording on the general wards.

AIM: To determine whether the implementation of a Reading-Modified Early Warning Scoring (R-MEWS) system, is associated with an increased recording of respiratory rate (RR) in hospital inpatients, and whether the presence of a critical care outreach (CCO) service has a further impact on the recording of patient's vital signs. METHOD: Five annual point prevalence surveys of all adult, non-obstetric acute inpatients (n=2638) in two Hospitals (A and B) were carried out between 2001 and 2005. The R-MEWS system was implemented incrementally in both hospitals to include all study group patients, but a CCO service was only available in Hospital A. Data were collected on numbers of patients, routinely documented physiological observations and R-MEW score. RESULTS: Respiratory rate (RR) recording increased from 6.0% in the first survey to 77.9% in the last, which correlated with the incremental implementation of the R-MEWS system. Hospital A that had the CCO service showed a greater increase in RR recording than Hospital B with no CCO service. CONCLUSION: The introduction of an early warning scoring (EWS) was associated with improved respiratory rate recording, which may have been further enhanced by the presence of a CCO service.

Compression or tension? The stress distribution in the proximal femur.

BACKGROUND: Questions regarding the distribution of stress in the proximal human femur have never been adequately resolved. Traditionally, by considering the femur in isolation, it has been believed that the effect of body weight on the projecting neck and head places the superior aspect of the neck in tension. A minority view has proposed that this region is in compression because of muscular forces pulling the femur into the pelvis. Little has been done to study stress distributions in the proximal femur. We hypothesise that under physiological loading the majority of the proximal femur is in compression and that the internal trabecular structure functions as an arch, transferring compressive stresses to the femoral shaft. METHODS: To demonstrate the principle, we have developed a 2D finite element model of the femur in which body weight, a representation of the pelvis, and ligamentous forces were included. The regions of higher trabecular bone density in the proximal femur (the principal trabecular systems) were assigned a higher modulus than the surrounding trabecular bone. Two-legged and one-legged stances, the latter including an abductor force, were investigated. RESULTS: The inclusion of ligamentous forces in two-legged stance generated compressive stresses in the proximal femur. The increased modulus in areas of greater structural density focuses the stresses through the arch-like internal structure. Including an abductor muscle force in simulated one-legged stance also produced compression, but with a different distribution. CONCLUSION: This 2D model shows, in principle, that including ligamentous and muscular forces has the effect of generating compressive stresses across most of the proximal femur. The arch-like trabecular structure transmits the compressive loads to the shaft. The greater strength of bone in compression than in tension is then used to advantage. These results support the hypothesis presented. If correct, a better understanding of the stress distribution in the proximal femur may lead to improvements in prosthetic devices and an appreciation of the effects of various surgical procedures affecting load transmission across the hip.

A mechanism for balancing the human body on the hips.

A mechanism for the postural balance of the human torso over the hip joints is reported that does not appear to have been fully recognised. The centre of gravity of the torso is usually considered poised above the hips. This is in a state of unstable equilibrium. Here, we propose that body weight acting through the sacrum is counter-balanced by tension in the ilio-femoral ligament; the hips acting as the fulcrum. This places the torso in stable equilibrium and means that balance may be maintained with minimal muscular forces. The joint reaction force due to this mechanism in a two-legged stance is then of the order of the body-weight on each hip. An implication is that capsular ligaments are important and consideration should be given to retaining or restoring them as much as possible in hip arthroplasty.

Phosphoglycerate kinase pseudogenes in the tammar wallaby and other macropodid marsupials.

Phosphoglycerate kinase (EC 2.7.2.3; PGK) exists in two forms in marsupials. PGK1 is an X-linked house-keeping enzyme, and PGK2 is a mainly testis-specific enzyme under autosomal control. We have used PGK1 probes derived from two closely related species of macropodid marsupials (kangaroos and wallabies) to demonstrate the existence of a large family of pseudogenes in the tammar wallaby (Macropus eugenii). Over 30 fragments are detectable after Taq digestion. We estimate that there are 25-30 copies per genome. Most are autosomally inherited and are apparently not closely linked. Only two restriction fragments that appeared to be sex linked could be detected. Varying degrees of hybridization of fragments to the probes suggest different levels of homology, and hence different ages of origin. The existence of two PGK1 homologous restriction fragments from the X and a large number from the autosomes was also demonstrated by somatic cell hybridization for two other macropodid species, the wallaroo (M. robustus) and the red kangaroo (M. rufus). These results are compared with those from human and mouse, and it is suggested that the propensity of PGK1 to form pseudogenes is an ancient (approximately 130 MYR BP) characteristic of mammals. The high level of polymorphism detected in the tammar makes these PGK1 probes potentially useful for measuring genetic variability in this species and other macropodids.

Progression of HIV-related disease is associated with HLA DQ and DR alleles defined by restriction fragment length polymorphisms.

A cohort of 139 hemophiliacs was typed for HLA D region genes by means of restriction fragment length polymorphisms (RFLPs) detected by HLA DQ and DR gene probes. Disease progression was studied in the 65 HIV antibody-positive patients, who were infected by contaminated clotting factor before 1985. Strong associations were found between disease progression in HIV-infected patients and allelic DNA fragments revealed by a DQ alpha cDNA probe. A 5.5 kb fragment was reduced in frequency and a 4.6 kb fragment increased in frequency (p less than 0.005) in the faster progressing group, as measured both by development of CDC Category IV clinical symptoms and CD4 number less than 200 x 10(6)/l. These results correlate with DR types deduced from the RFLP patterns revealed by DR beta and DQ alpha gene probes. A decrease in DR4 and an increase in both DR5 and the DR3 subtype found in the A1 B8 DR3 haplotype were associated with disease progression (p less than 0.05).