Biomechanics of intramedullary fracture fixation

Intramedullary rodding allows excellent control of bending forces on long bone fractures when adequate sized rods are used. This is made possible by reaming when necessary. Torsional stability is poor if adequate bone nail contact is not obtained and there is little bone fragment interdigitation. This can be optimized with the interlocking system, especially with proximal and distal fractures. Intramedullary rods allow transmission of compressive load so there must be adequate bone to bone contact without comminution to prevent shortening. If a great deal of comminution is present, an interlocking system must be used to resist compressive loads. The interlocked devices have not been proven to be a detriment to union and indeed are a semi-rigid fixation system when used in comminuted shaft fractures. The strength of an osteosynthesis with an intramedullary rod depends on the geometry of the rod and the geometry of the fracture complex. Both locked and nonlocked intramedullary rods perform extremely well when one understands the mechanical principles involved in intramedullary rodding and pays close attention to detail.     

Malignant phaeochromocytoma

Malignant phaeochromocytoma is a rare tumour and experience in its management is therefore limited. Five patients are discussed in whom the development of metastases was associated with rapidly progressive disease.     

Levels of the Candida metabolite D-arabinitol in sera of steroid-treated and untreated patients with sarcoidosis.

We measured the Candida metabolite D-arabinitol and its enantiomer L-arabinitol in 42 serum samples from 33 patients with sarcoidosis and compared the results with those from 27 healthy adults and 4 patients with candidiasis. The D- and L-arabinitol concentrations and the D- and L-arabinitol/creatinine ratios did not differ significantly in the sarcoidosis patients and the controls; the D-arabinitol concentrations and the D-arabinitol/creatinine ratios were much higher in the patients with candidiasis. Among the patients with sarcoidosis, the D- and L-arabinitol levels in the steroid recipients did not differ significantly from those in patients not receiving steroids. Higher D-arabinitol/creatinine ratios were associated with roentgenographic evidence of pulmonary fibrosis and low forced vital capacities, but not with disease activity as determined by the proportion of lymphocytes to total nucleated cells in bronchoalveolar lavage fluid or the CD4/CD8 ratio in bronchoalveolar lymphocytes. We conclude that neither sarcoidosis nor corticosteroid treatment is associated with high levels of D-arabinitol in serum.     

Failure to Find Hyperactivity in Preschool Children with Moderately Elevated Lead Burden

Children evidencing moderately increased lead burden (n = 40)were compared to children not evidencing increased lead burden(n = 48) on three measures of hyperactivity. All children werescreened at a local county health department because of suspectedlead exposure or as part of the Early and Periodic Screening,Diagnosis, and Treatment program. The three measures of activitywere the Routh-Schroeder-O'Tuama free-field measure of grossmotor activity, the Conners Parent Rating Scale, and the Werry-Weiss-PetersActivity Scale, both of the latter completed by the parents.As in previous research, a consistent age effect in gross motoractivity was found. No difference was found between the groupsin gross motor activity or in parental report of activity level.The results suggest that using three of the most widely usedmeasures of hyperactivity, moderate lead exposure does not resultin overactivity in preschool-aged children.     

Nutritional support of the critically ill. Part I--Review.

Critically ill patients seen in an adult Intensive Care Unit often exhibit a hypermetabolic, hypercatabolic response to the stress of illness. The hypercatabolic response to trauma and sepsis is discussed in relation to macronutrient metabolism in this first of a two part article. The aim of nutrition therapy is provision of appropriate substrates to minimize the loss of lean body mass, without provoking additional metabolic stress. Selected topics in nutritional support are reviewed, with emphasis on current research and controversies in the care of the critically ill.     

Computed tomography in diagnosis and management of multiple myeloma and its variants

The use of computed tomography (CT) was evaluated in 25 patients with multiple myeloma, six with extramedullary plasmacytoma, and two with undiagnosed lesions. We found that CT was useful for (1) patients with multiple myeloma who had bone pain but normal roentgenograms, (2) patients with an M-protein, bone marrow plasmacytosis, and back pain from osteoporosis and compression fractures but an inconclusive diagnosis of multiple myeloma, (3) the determination of extent of tumor, and (4) guidance in needle biopsy.     

Cardiovascular and thermal responses of triathlon performance

Triathletes typically train each triathlon event separately. Therefore, to determine the cardiovascular and thermal differences between training and triathlon performance, nine male triathletes performed a simulated 75-min (40 km) control bike and a 40-min (10 km) control run at 70% of maximal oxygen uptake. Control data were compared to data derived from a simulated triathlon (0.8-km swim, 75-min bike, and 40-min run). Results demonstrated that prior swimming significantly decreased (P less than 0.05) triathlon cycling work output (191 +/- 4.2 to 159 +/- 7.6 W) producing mean differences (P less than 0.05) in oxygen uptake (3.18 +/- 0.1 to 3.01 +/- 0.11.min-1), ventilation (84.7 +/- 4 to 80.4 +/- 4.21.min-1), stroke volume (128 +/- 7.1 to 118 +/- 3.5 ml.min-1), cardiac output (20.7 +/- 1.2 to 18.9 +/- 0.8 l.min-1), mean arterial pressure (105 +/- 3.8 to 96 +/- 7.9 mm Hg) and rectal temperature (38.2 +/- 0.2 to 38.4 +/- 0.3 degrees C). Triathlon running, while performing identical control work output, elicited significant increases (P less than 0.05) in oxygen uptake (3.41 +/- 0.1 to 3.85 +/- 0.1 l.min-1), ventilation (91.3 +/- 3.3 to 104.2 +/- 2.8 l.min-1), heart rate (161 +/- 3.1 to 174 +/- 3.6 beats.min-1), arteriovenous oxygen difference (15.3 +/- 0.2 to 17.2 +/- 0.3 ml.100 ml-1) and rectal temperature (38.3 +/- 0.2 and 39.2 +/- 0.3 degrees C) with significantly lower (P less than 0.05) stroke volume (138 +/- 2.4 to 129 +/- 3.6 ml.min-1) and mean arterial pressure (102 +/- 11.2 to 89 +/- 5.5 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Polymyalgia rheumatica/giant cell arteritis in a Cambridge general practice

The aim of this study was to establish the incidence and prevalence of polymyalgia rheumatica/giant cell arteritis in general practice. Patients with this disorder, whether previously diagnosed or not, were ascertained by using a questionnaire administered by interview, and all received full clinical and laboratory assessment. A total of 579 patients aged 65 and over was seen, and 19 (33/1000) had been diagnosed or developed symptoms within the previous eight years. Thus the calculated annual incidence in those aged 65 and over was about 4/1000. The figures from this first large scale study of polymyalgia rheumatica/giant cell arteritis in general practice are much higher than those from studies carried out in hospital. The questionnaire was effective in both identifying known cases of polymyalgia rheumatica/giant cell arteritis and detecting new cases. As this is a treatable disorder, it is important that doctors become aware of how common it is in elderly people.     

The effect of age on salicylate-induced nephrotoxicity in male rats

The administration of 500 mg/kg sodium [14C]salicylate to 3- and 12-month-old male rats produced proximal tubular necrosis in the older animals but only mild nonspecific cellular changes in the younger group. The onset of renal damage was similar for both 3- and 12-month-old rats but recovery time was prolonged in the older rats. Covalent binding of salicylate equivalents was present in renal cortices from all rats and was largely confined to the mitochondrial fraction; however, older rats displayed five times more binding to this organelle than younger rats. Also the mitochondrial pathway for salicylurate synthesis was significantly inhibited in the older animals. These results demonstrate the existence of an age-dependent susceptibility to salicylate nephrotoxicity and suggest that mitochondrial injury may play an important role in the development of salicylate-induced proximal tubular necrosis.     

Effect of intravitreal hyaluronidase on the clearance of tritiated water from the vitreous to the choroid.

The rate of transfer of intravitreally injected tritiated water from the mid vitreous to the choroid is significantly increased after depolymerization of vitreous hyaluronic acid by injected hyaluronidase. The significance of this finding is discussed in relation to such conditions as retinal detachment and reattachment.