External fixation of unstable pelvic ring fractures: comparative rigidity of some current frame configurations

The effectiveness of external fixation in the stabilisation of pelvic ring fractures was studied in a laboratory cadaveric series. Shearing displacements occurring at sacroiliac joint and symphysis pubis dislocation sites, due to simplified longitudinal loading of the sacrum in an Instron unit, were monitored using variable-impedence transducers. The rigidity of fixation was compared for the Slätis and the Bonnel single anterior frames, for coupled and uncoupled double anterior frames, and for combined anterior-plus-posterior fixation achieved with separate transfixation pin clusters, with through-and-through pin clusters, or with a posterior screw plate. The data showed that the use of posterior fixation provided greatly enhanced stabilisation compared to that achieved with anterior fixation alone. The complex double anterior frames performed only slightly better than did the simpler single anterior frames. In no case, however, was it possible to recover rigidity levels approaching those of the intact pelvis. The results suggest that the transfixation pin arrangement is the most important determinant of pelvic fixation stability, and that further investigation of posterior screw-plate fixation is warranted.     

Atlas of Hox gene expression in the developing kidney.

Hox genes often play important roles in segment identity determination and organogenesis. To better understand the roles of Hox genes during kidney development, we performed an extensive analysis of their expression patterns. Section in situ hybridizations were used to define the expression of 37 Hox genes at embryonic day (E) 12.5, E13.5, E15.5, and E17.5 of kidney development. Several interesting principles emerged. First, the concept of colinearity was preserved. Hox genes from the more 3' positions in clusters were more often expressed in the ureteric bud, which is derived from the anterior of the intermediate mesoderm. Second, Hox genes were expressed throughout the ureteric bud without any segment specificity. Third, in the different segments of the forming nephron we did observe overlapping domains of Hox gene expression, which initiated distally at the junction between the nephron and ureteric bud, and extended proximally variable distances. Finally, we observed that paralogous Hox genes often showed surprisingly diverse expression patterns. Indeed, contiguous genes on a single cluster more often showed similar expression patterns than paralogs. In summary, the resulting atlas of Hox gene expression provides a foundation for further study of the overlapping functions Hox genes in the developing kidney.     

Thermal tolerance following artificially induced polycythaemia

Polycythaemia has been shown to improve physical performance, possibly due to increased arterial oxygen transport. Enhanced thermoregulatory function may also accompany this manipulation, since a greater proportion of the cardiac output becomes available for heat dissipation. We further examined this possibility in five trained men, who participated in three-phase heat stress trials (20 min rest, 20 min cycling at 30% peak power W_peak and 20 min at 45% W_peak at 38.3 (SEM 0.7)°C [relative humidity 41.4 (SEM 2.9)%]. Trials were performed during normocythaemia (control) and polycythaemia, obtained by reinfusion of autologous red blood cells and resulting in significant elevation of arterial oxygen transport. During the polycythaemic trials, the subjects demonstrated diminished thermal strain, as evidenced by a significant reduction in cardiac frequency (f _c: 12 beats · min^–1 lower throughout the test;P < 0.05), and reduced auditory canal temperatures (T _ae) during the latter 20-min phase (P < 0.05). Forearm sweat onset was more rapid (363.0 compared to 1083.0 s;P < 0.05), and forearm sweat rate (. _msw) sensitivity was elevated from 1.80 to 2.91 · mg · cm^–2 · min^–1 · °C^–1 (P < 0.05). Foreheadm _sw was depressed during the final 20 min, while forearmm _sw was greater during all test phases, averaging 0.94 and 1.20 mg · cm^–2 · min^–1, respectively, over the 60 min. Skin blood flows for the upper back, upper arm and forearm were reduced (P < 0.05). Polycythaemia enhanced thermoregulation, through an elevation in forearm sweat sensitivity and.m _sw, but not via increased cutaneous blood flow. These modifications occurred simultaneously with decreases inf _c andT _ae, resulting in greater thermal tolerance.     

Arthroscopic washout of the knee--a 5-year survival analysis

Arthroscopy and washout of the knee is commonly performed for early osteoarthritis. Very little information exists regarding long-term prognosis, especially in terms of avoidance of further surgery. Using a prospectively gathered database, 100 consecutive patients having knee arthroscopy with a finding of OA between 1991 and 1993 were identified and their outcome at 5 years ascertained. Ninety-nine patients with 100 arthroscoped knees were identified. Fifty-eight had isolated medial compartment disease and six had isolated lateral compartment disease. In 36, both compartments were affected. Eighteen knees had further major surgery during follow up; 11 had total knee replacement, four had high tibial osteotomy and three had unicondylar knee arthroplasty. Those requiring surgery were significantly older (62 cf. 53 years, P=0.008). Meniscectomy was not an important risk factor (chi2, P=0.67). The rate of knee survival without operation at 5 years was much lower in those aged over 60 years than in those younger (68% cf. 89%). (chi2, P=0.02). Only 18% of patients progress to major knee surgery within 5 years of arthroscopic washout for osteoarthritis. Age greater than 60 years worsens the prognosis considerably.     

The matrix metalloproteinase-3 (MMP-3) 5A/6A promoter polymorphism is not associated with ischaemic heart disease: analysis employing a family based approach

Matrix metalloproteinase-3 (MMP-3) has been proposed as an important mediator of the atherosclerotic process. The possible role of the functional -1612 5A/6A polymorphism of the MMP-3 gene in the susceptibility to ischaemic heart disease (IHD) was investigated in a well-defined Irish population using two recently described family based tests of association. One thousand and twelve individuals from 386 families with at least one member prematurely affected with IHD were genotyped. Using the combined transmission disequilibrium test (TDT)/sib-TDT and the pedigree disequilibrium test (PDT), no association between the MMP-3 -1612 5A/6A polymorphism and IHD was found. Our data demonstrate that, in an Irish population, the MMP-3 -1612 5A/6A polymorphism is not associated with IHD.     

Bilateral Skin Conductance and Skin Potential in Schizophrenic and Normal Subjects: The Identification of the Fast Habituator Group of Schizophrenics

Chronic schizophrenics from three different hospitals were compared to normal subjects on skin conductance parameters. In addition to “Responders” and “Nonresponders” as reported by Gruzelier and Venables (1972), a group of “Fast Habituator” schizophrenics was found. These subjects produce one or at most two responses before habituation in an orienting series. The SC waveform of fast habituator subjects shows long latency, slow risetime and long recovery, although the amplitude of response is within normal limits.     

Trimellitic anhydride-induced airway syndromes: Clinical and immunologic studies

This report describes a spectrum of respiratory symptoms in workers exposed to trimellitic anhydride (TMA), a biologically reactive chemical used in the plastics industry. Fourteen workers who had worked on a unit which synthesized TMA were evaluated by clinical and immunologic methods. Respiratory syndromes induced by TMA inhalation included asthma and rhinitis of the immediate type, late onset asthma with systemic symptoms, and airway irritation. TMA was shown to couple rapidly to human serum albumin, forming an immunoreactive hapten-protein complex. The workers' immunologic reactivity to this complex could be quantitated and correlated with the three respiratory syndromes. The asthma-rhinitis syndrome was mediated by IgE antibody specific for the TMA hapten. The syndrome of late onset asthma with systemic symptoms was accompanied by elevated levels of TMA-specific IgG antibody. Rheumatoid factor in high titer was found in one worker with IgE-mediated asthma and in two workers with asthma of late onset. Lymphocyte reactivity of TMA-HSA was demonstrated in three workers representative of the three clinical syndromes. Leukocyte histamine release was demonstrated to TMA-HSA in one worker with high levels of IgE antibody specific for TMA-HSA who had severe symptoms of acute rhinitis and asthma.