Preparedness for highly pathogenic avian influenza pandemic in Africa

Africa’s strategies for pandemic influenza must also strengthen overall public health capacity.

Global concerns about an impending influenza pandemic escalated when highly pathogenic influenza A subtype H5N1 appeared in Nigeria in January 2006. The potential devastation from emergence of a pandemic strain in Africa has led to a sudden shift of public health focus to pandemic preparedness. Preparedness and control activities must work within the already strained capacity of health infrastructure in Africa to respond to immense existing public health problems. Massive attention and resources directed toward influenza could distort priorities and damage critical public health programs. Responses to concerns about pandemic influenza should strengthen human and veterinary surveillance and laboratory capacity to help address a variety of health threats. Experiences in Asia should provide bases for reassessing strategies for Africa and elsewhere. Fowl depopulation strategies will need to be adapted for Africa. Additionally, the role of avian vaccines should be comprehensively evaluated and clearly defined.

No evidence of avian influenza A (H5N1) among returning US travelers

We reviewed reports to the Centers for Disease Control and Prevention of US travelers suspected of having avian influenza A (H5N1) virus infection from February 2003 through May 2006. Among the 59 reported patients, no evidence of H5N1 virus infection was found; none had direct contact with poultry, but 42% had evidence of human influenza A.

Who gets hospitalized for influenza pneumonia in Thailand? Implications for vaccine policy

Risk factor information for severe complications of interpandemic influenza is needed to inform vaccine policy in Thailand. We identified patients with lab-confirmed influenza who were hospitalized with pneumonia during September 2003 to August 2004. Among the 80 case-patients identified through a population-based pneumonia surveillance system in eastern Thailand, cases were 6.2 and 11.1 times more likely to be among persons<1 year old and >75 years old, respectively, compared with the overall population. Cases were also 7.6 times more likely to have chronic respiratory disease. In Thailand, the young, elderly, and those with chronic disease were at high risk for hospitalized pneumonia from influenza.

Recalcitrant nonunion of the distal humerus: treatment with free vascularized bone grafting

We sought to determine whether open reduction and internal fixation in combination with free vascularized bone grafting and elbow contracture release is an effective treatment for patients with recalcitrant distal humeral nonunions with segmental bone loss. In addition, we wondered whether this treatment strategy has an acceptable complication rate. Five patients, with an average age of 48 years, form the basis of our study. An average of 3.4 surgical procedures were done before the vascularized bone grafting for treatment of nonunion. The average time from injury until the index vascularized graft was 37.2 months. All patients had elbow pain at rest and had severe functional limitations related to the nonunion. There was segmental bone loss averaging 3.2 cm at the time of vascularized grafting. Four of the five patients with nonunions had clinical and radiographic union at the latest followup, and one patient required a total elbow arthroplasty because of articular collapse after the vascularized grafting procedure. The average time from vascularized grafting until bony union was 4.5 months (range, 3-6 months). There were no other complications in this patient group. Free vascularized bone grafting is a treatment alternative for distal humeral fracture nonunion, especially in younger patients who have nonunions with segmental bone loss that are refractory to conventional fixation and bone grafting techniques.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series--no, or historical, control group). See the Guidelines for Authors for a complete description of levels of evidence.

Pharmacokinetics of an immediate-release oral formulation of Fampridine (4-aminopyridine) in normal subjects and patients with spinal cord injury

Plasma concentration profiles of the K+ channel-blocking compound Fampridine were obtained from (1) control subjects (n = 6) following oral administration of doses of 10, 15, 20, and 25 mg and (2) patients with spinal cord injury (SCI) (n = 11) following a single oral dose of 10 mg of an immediate-release formulation. Plasma concentrations were determined using a reversed-phase ion-pair high-performance liquid chromatography (HPLC) assay with ultraviolet light detection employing liquid extraction. The drug was rapidly absorbed with a tmax approximately 1 hour for both groups; tmax was independent of dose. Cmax and AUC0-infinity were linearly related to dose, and t 1/2 was 3 to 4 hours for both groups. There were no obvious differences in the (10-mg) plasma concentration profiles between control subjects and SCI patients. The drug was well tolerated, with only mild and transient side effects of light-headedness, dysesthesias, and dizziness.

Refinements in stress echocardiographic techniques improve inter-institutional agreement in interpretation of dobutamine stress echocardiograms

AIMS

To determine the degree of inter-institutional agreement in the assessment of dobutamine stress echocardiograms using modern stress echocardiographic technology in combination with standardized data acquisition and assessment criteria.

METHOD AND RESULTS

Among six experienced institutions, 150 dobutamine stress echocardiograms (dobutamine up to 40 microg x kg(-1) min(-1) and atropine up to 1 mg) were performed on patients with suspected coronary artery disease using fundamental and harmonic imaging following a consistent digital acquisition protocol. Each dobutamine stress echocardiogram was assessed at every institution regarding endocardial visibility and left ventricular wall motion without knowledge of any other data using standardized reading criteria. No patients were excluded due to poor image quality or inadequate stress level. Coronary angiography was performed within 4 weeks. Coronary angiography demonstrated significant coronary artery disease (> or = 50% diameter stenosis) in 87 patients. Using harmonic imaging an average of 5.2+/-0.9 institutions agreed on dobutamine stress echocardiogram results as being normal or abnormal (mean kappa 0.55; 95% CI 0.50-0.60). Agreement was higher in patients with no (equal assessment of dobutamine stress echocardiogram results by 5.5+/-0.8 institutions) or three-vessel coronary artery disease (5.4+/- 0.8 institutions) and lower in one- or two- vessel disease (5.0+/-0.9 and 5.2+/-1.0 institutions, respectively; P=0.041). Disagreement on test results was greater in only minor wall motion abnormalities. Agreement on dobutamine stress echocardiogram results was lower using fundamental imaging (mean kappa 0.49; 95% CI 0.44-0.54; P<0.01 vs harmonic imaging).

CONCLUSION

Modern echocardiographic technology in combination with standardized digital image processing and uniform reading criteria results in a higher inter-institutional agreement in the interpretation of dobutamine stress echocardiogram compared to historic reports.

Contribution of acetabular labrum to articulating surface area and femoral head coverage in adult hip joints: an anatomic study in cadavera

The purpose of our study was to describe the gross anatomy of the adult acetabular labrum and to determine its contribution to the depth, surface area, and volume of the acetabulum. Fifty-five embalmed hips were studied. Each hip was disarticulated, and standardized measurements were taken. Calculations of the acetabular articulating surface area and volume, with and without the labrum, were performed based on these measurements. Average width of the acetabular labrum was 5.3 mm (SD, 2.6 mm). The labrum was wider anteriorly and superiorly than posteriorly. The surface area of the acetabulum without the labrum was 28.8 cm2; with the labrum, it was 36.8 cm2 (P < .0001). The volume of the acetabulum without the labrum was 31.5 cm3; with the labrum, it was 41.1 cm3 (P < .0001). There was no side-to-side difference in contribution of the labrum to either surface area or volume between right and left hips. Comparison of these indices for males and females showed statistically significant differences in absolute but not relative increases.

Effects of forearm rotation on the clinical evaluation of ulnar variance

Neutral rotation radiographs of the wrist are recommended to standardize the measurement of ulnar variance because it is known that changes in forearm rotation result in changes of this measurement. The purpose of this study was to examine whether there are clinically measurable differences in ulnar variance between radiographs in various degrees of forearm rotation in human subjects. Forty-five wrist radiographs of 15 normal adults were obtained in 3 positions: maximum forearm pronation, neutral rotation, and maximum supination. The ulnar variance on each view was measured by 3 independent observers using a standard millimeter ruler. The average absolute difference in ulnar variance was 0.4 mm between pronation, 0.6 mm between pronation and supination, and 0.2 mm between neutral and supination. Although we found a statistically significant difference in ulnar variance between the pronated and neutral positions, this difference may not be clinically significant and may not justify concerns of forearm position during the radiographic evaluation of ulnar variance.

Computed tomography scanning of intra-articular distal radius fractures: does it influence treatment?

The purpose of this study is to determine whether the addition of computed tomography (CT) results in changes in the evaluation and treatment of intra-articular distal radius fractures. Fifteen intra-articular distal radius fractures were evaluated independently by 4 hand surgeons. Plain x-rays were reviewed initially followed by the corresponding CT scans for comparison of articular step-off and gapping, comminution, and treatment. Kappa coefficients (kappa) of intraobserver and interobserver reliability for treatment plans were generated. Computed tomography scans improved the sensitivity of measurement of articular surface gapping, improved the accuracy of detection of comminution and distal radioulnar joint involvement, and altered proposed treatment plans within observers (intraobserver agreement: kappa =.54, moderate) and improved agreement of proposed treatment plans between observers (kappa =.34 to kappa =.44, fair to moderate). Computed tomography scanning influenced observers to change treatment plans and resulted in increased interobserver reliability in the proposed management of these injuries.

Determining femoral rotational alignment in total knee arthroplasty: reliability of techniques

Several anatomic axes routinely are used for determining femoral rotational alignment in total knee arthroplasty. The purpose of this study was to determine the reliability of these techniques. The transepicondylar axis, anteroposterior axis, and balanced flexion gap tension line were identified relative to the posterior condylar axis in 8 fresh frozen cadaver knees by 3 independent observers. The flexion-extension axis was defined in each knee for comparison. The anteroposterior and balanced tension axes defined most reliably the flexion-extension axis and best balanced the flexion gap with no significant interobserver differences. The transepicondylar axis was less predictable and significantly more externally rotated than the anteroposterior axis (P < .005) and the balanced tension line (P < .00001). Flexion gap tensioning may offer superior reliability because of its independence of obscured or distorted bone landmarks.

Role of computed tomography in the classification and management of pediatric pelvic fractures

In adults, pelvic computed tomography (CT) scanning plays an important role in the treatment of pelvic fractures; however, the role of CT scanning in the management of pediatric pelvic fractures is unclear. The purpose of this study was to investigate the efficacy of CT scanning in the management of pelvic fractures in children. One hundred three consecutive patients were identified. All patients underwent anteroposterior plain radiographic evaluation; CT scans were performed in 62. Three orthopaedic surgeons independently reviewed the plain radiographs and determined fracture classification and management. Subsequently, each observer was shown corresponding CT scans and again determined classification and management. Interobserver agreement was calculated using Kappa statistics. After the addition of CT scans, the mean changes in classification were nine (15%) and in management two (3%). Plain radiographs alone reliably predicted the need and type of operative intervention. Kappa statistics demonstrated "excellent" agreement for classification and management without and with CT scans. We reliably determined fracture classification and management based on plain radiographs alone.

Evaluation of the sigmoid notch with computed tomography following intra-articular distal radius fracture

A classification system for disruption patterns of the sigmoid notch of the radius associated with distal radius fractures has not been established. Using plain x-rays and corresponding computed tomography (CT) scans we characterized and quantified the types of sigmoid notch involvement in 20 consecutive distal radius fractures with radiocarpal joint extension. Plain radiographs revealed fracture extension into the sigmoid notch in only 7 cases (35%) and the CT scans demonstrated fracture extension into the sigmoid notch in 13 cases (65%). Of the 13 fractures with sigmoid notch involvement, 9 (69%) were displaced and 4 (31%) were nondisplaced. Sigmoid notch articular step-off (n = 7) and gapping (n = 9) were detectable on the CT scans but not on the x-rays. Plain x-rays appear to underestimate sigmoid notch involvement following distal radius fractures. In addition, CT appears to be a superior diagnostic modality for quantifying sigmoid notch fracture step-off and articular gapping.

Nodular fasciitis of the hand: a case report

Nodular fasciitis is a benign, reactive fibroblastic soft tissue tumor. Involvement of the hand is exceedingly rare. A case of nodular fasciitis involving the dominant hand of a 38-year-old woman is reviewed, and its clinicopathologic features are presented. Because of its rapid growth and aggressive histologic appearance, nodular fasciitis can be mistaken for a soft tissue sarcoma, despite its benign clinical behavior. For this reason, aggressive surgical resection should be avoided.

[Hemostatic closure of arterial puncture site using Angio-Seal after diagnostic heart catheterization or coronary intervention]

Conventional manual compression and subsequent application of pressure bandages is associated with prolonged immobility and significant patient discomfort. Routine anticoagulation as well as the use of new interventional devices and platelet inhibiting strategies lead to a higher incidence of local bleeding complications after diagnostic cardiac catheterization or coronary angioplasty. Immediate sheath removal increases patient comfort. The Angio-Seal system uses a biodegradable anchor and collagen plug for sealing of arterial puncture sites. Several studies showed the safety and efficacy of this device. Technical deployment success ranges between 88 and 100%. Significant reduction in time to hemostasis allows for earlier patient ambulation and shorter in-hospital stay compared to manual compression with peripheral complications not being increased.

Computed tomographic scanning of cervical spine fractures: does it influence treatment?

OBJECTIVE

To determine whether the superior sensitivity of computed tomography (CT) results in changes in treatment plans for cervical spine fractures that have been diagnosed on plain films alone.

DESIGN

Retrospective review of radiographic studies for cervical spine trauma.

SETTING/PARTICIPANTS

An orthopaedic spine surgeon (SS), an orthopaedic traumatologist (OT), an orthopaedic spine fellow (SF), and an orthopaedic chief resident (CR) were independently presented thirty-nine cases of cervical spine trauma imaged with adequate plain radiographs and with CT.

MAIN OUTCOME MEASURES

Agreement was measured by calculation of kappa coefficients.

RESULTS

The detection rate of total fractures on plain radiographs alone ranged from 47 percent to 71 percent, and the diagnosis changed an average 53 percent of cases. Change in treatment plans ranged from 10 percent (SS) to 46 percent (CR) of cases. Of these changes, undertreatment occurred as follows: SS =3 percent, OT =8 percent, SF =36 percent, and CR = 46 percent. The mean kappa coefficient for intraobserver agreement of treatment plans was 0.69. The experienced observers demonstrated "excellent" agreement with an average kappa coefficient of 0.85, whereas the mean coefficient for inexperienced observers was 0.54 or "moderate" agreement. Complete diagnostic agreement occurred between the experienced observers after review of both the plain films and CT scans. The interobserver agreement of treatment plans for the experienced observers increased from 0.79 to 0.88.

CONCLUSIONS

CT scanning afforded additional information for all observers. Experienced observers can reliably determine treatment plans for cervical spine trauma diagnosed on plain films alone, whereas inexperienced observers are less reliable. For the experienced observers, interobserver agreement on treatment plans increased after the addition of CT.

The glomerular barrier fits a two-pore-and-fiber-matrix model: derivation and physiologic test

Failure of the glomerular barrier causing proteinuria has been modeled chiefly by Chang, Deen, and Brenner. They have refined models from an isoporous filter to a mostly isoporous membrane, which during proteinuric disease opens up nondiscriminating shunts. This report extends these concepts by measuring a larger distribution of macromolecular tracer sizes and bringing in a fiber matrix. By clearance methods, glomerular sieving curves of relatively neutral tetramethyl rhodamine aminodextran from radii of 15 to over 80 A were obtained and fitted to theory. Two pores filled with matrix fit all data without exception, and no other model did. Five parameters described the curve in control rats and in proteinuric rats made so by albumin injections. From highest to lowest degree of confidence, these were small and large pore radii ros = 42.7 +/- 0.9 SEM A and rol = 926 +/- 156 A; small to large pore density ns/nl = 3859 +/- 942; mean fiber radius rf = 20.3 +/- 1. 1 A; and fiber void volume ratio epsilon = 0.52 +/- 0.05. In proteinuria, ros rose 13% (P = 0.002), nl increased 150% (P = 0.04), and there was a compensatory rise in rf of 26% (P = 0.002). The consideration of basement membrane and glycocalyx remain to be incorporated into the model. Moreover, the closeness of rf to ros indicates that fiber matrix theory may need modification for a complete description.

Albumin reduces basement membrane hydraulic conductance in part due to arginyl side groups

Albumin reduces capillary hydraulic conductance (Lp) even at low concentrations. To determine if part of this barrier protective effect might be extracellular, we studied the effects of bovine serum albumin (BSA) on Lp of self-assembled basement membrane (Matrigel). Lp with tris(hydroxymethyl)aminomethane (Tris) buffer superfusate was stable at 1.77 +/- 0.22 x 10(-5) (SE) cm.s-1.cmH2O-1 over several hours. At 0.1 g/dl BSA, experimental/control (Tris) Lp fell to 83.1 +/- 6.0% (2P < 0.025), with decreases to 72.4 +/- 3.7% at 1 g/dl (2P < 0.005), 45.3 +/- 5.1% at 2.5 g/dl (2P < 0.001), and 45.0 +/- 4.8% at 4.0 g/dl (2P < 0.001). In separate experiments, BSA arginine groups were neutralized by 1,2-cyclohexanedione (CHD), and experimental/control Lp values were measured. At 2.5 g/dl, CHD-BSA depressed Lp to 54.4 +/- 4.8%, while unmodified BSA reduced Lp to 40.8 +/- 3.5% of Tris control (2P = 0.05). Finally, soluble arginine at three- and sixfold the arginine in BSA was added to BSA superfusate. For threefold, Lp rose to 120 +/- 8% of BSA level and for sixfold to 129 +/- 9% (2P < 0.05). We conclude that some part of the albumin protective effect is very likely due to consequences on extracellular matrix and that at least 18-22% of this effect is related to arginine groups on albumin when computed from Lp, and up to 34% when viscosity is taken into account. Membrane-saturable arginine-binding sites can be unbound with arginine, thus nullifying part of the barrier protective effect of BSA.

Fiber matrix descriptors from permeability data without requiring membrane thickness: theory, results, and optimization

OBJECTIVE

Permeability of basement membrane and all other barriers contains a term for membrane thickness (delta x). This naturally leads to development of methods for measuring delta x that are imprecise, inaccurate, expensive, subject to preparation artifact, and inattentive to variability. Although height and shape of permeability (P) vs. probe radius (aE) curves are sensitive to delta x, In(P) or In (P/free diffusivity or D0) curves have shapes independent of delta x. It should, thus, be possible using such characteristics to determine fiber radius (rf) and void volume ratio (epsilon) without delta x. We developed such a method to derive membrane structure by the standard model of Ogston and present its experimental evaluation.

METHODS

Basement membranes were self-assembled using 1:1 Matrigel: 0.01 M Tris/150 mM NaCl/1.0 mM CaCl2 buffer on 0.4-mu polycarbonate supports with transport measured in diffusion chambers using FITC-labeled hydroxyethyl starch probes from 25 to 102 A in radius. Sampling was at 0.5 hr and then for each hour up to 5. Other membranes were measured 7 days after formation.

RESULTS

The best fit of the new technique occurred at 3 hr with R2 = 0.949 +/- 0.003 SEM, rf = 36.8 = 2.4 A, and epsilon = 0.87 +/- 0.02. Membranes studied for 7 days showed more variability but essentially the same characteristics.

CONCLUSIONS

Membrane thickness is not necessary to reduce permeability of basement membrane to structure, and optimum sampling time is 3 hr.

The fate of hypertonic saline administered during hemodialysis

The possibility of postdialysis hypernatremia is one reason nephrology nurses do not administer hypertonic saline (HS) to treat hypotension or muscle cramps during the last hour of hemodialysis (HD). A single group time series quasi-experimental design was used to evaluate the effect of 50 mEq of HS given during the last hour of HD on interdialytic weight and serum sodium (PNa) and dialysate sodium (DNa) levels. Ten subjects experiencing hypotension or cramps during the last hour of HD, but not during the final 15 minutes, received 50 mEq of HS. One preinjection PNa and DNa sample was obtained, followed by the collection of 8 PNa and 42 DNa samples during the 5 minutes subsequent to the HS injection. Interdialytic weight was evaluated for differences. The results indicated that a statistically significant, but minor amount of sodium was removed in the dialysate (8.77% mEq/L + .96). In addition, the amount of sodium retained over a longer time scale was clinically insignificant, as evidenced by no significant change in the interdialytic weight following administration of 50 mEq of HS. PNa rose 12.7 + 1.3 mEq/L to a peak of 152.2 + 1.6 mEq/l in 54 + 2 seconds, returning to 3 + 0.3 mEq above baseline at 5 minutes. In conclusion, administration of HS up to the final 15 minutes of HD is safe therapy for hypotension and muscle cramps because it does not cause an increased interdialytic weight gain.

Increased depth of trophoblast invasion after chronic constriction of the lower aorta in rhesus monkeys

OBJECTIVE

Our purpose was to investigate whether a reduction in uteroplacental perfusion pressure would produce changes in trophoblast-uterine interactions at the cellular level.

STUDY DESIGN

Strictures were placed around the abdominal aortas of rhesus monkeys at 116 +/- 7 days of pregnancy to reduce uteroplacental perfusion pressure. Placental bed biopsy specimens were obtained at cesarean section, and cytotrophoblasts were identified by means of an anticytokeratin antibody.

RESULTS

In monkeys without aortic strictures, interstitial trophoblast invasion was restricted to the outer half of the endometrium. Endovascular trophoblast invasion involved the entire endometrial portion of uterine vessels and extended through the subjacent half of their myometrial segments. In seven of nine monkeys with aortic strictures the depth of interstitial trophoblast invasion was substantially increased and extended throughout the entire decidua and at least a portion of the myometrium. In contrast, the pattern of endovascular trophoblast invasion was identical to that observed in the placental beds of control animals.

CONCLUSION

These results suggest that uteroplacental perfusion pressure or oxygen content may be important physiologic factors controlling the depth of interstitial cytotrophoblast invasion.

Experimental preeclampsia produced by chronic constriction of the lower aorta: validation with longitudinal blood pressure measurements in conscious rhesus monkeys

OBJECTIVES

Our goals were (1) to determine whether hypertension, proteinuria, and glomerular endotheliosis can be produced by chronic reduction of lower aortic pressure in pregnant rhesus monkeys and (2) to study the time course of the development of hypertension by means of longitudinal arterial blood pressure measurements in conscious, unrestrained pregnant rhesus monkeys.

STUDY DESIGN

Indwelling arterial catheters were placed at 103 +/- 4 days of gestation (term 160 days) for measurement of arterial pressure before and after reduction of lower aortic pressure. At 116 +/- 7 days lower aortic pressure was reduced by 24 +/- 11 mm Hg in 11 monkeys (experimental group) by a stricture on the aorta just below the renal arteries; six monkeys (controls) underwent a sham operation. Resting on the aorta just below the renal arteries; six monkeys (controls) underwent a sham operation. Resting pressures were measured three to five times per week by a tether-and-swivel system.

RESULTS

Baseline arterial pressure averaged 81 +/- 6 mm Hg. In the experimental group four monkeys had adverse outcomes (one maternal death with severe hypertension, one abruptio placentae with stillbirth, and two spontaneous preterm deliveries with hypertension). There was one preterm delivery in the control group. Of the seven monkeys with aortic stricture who continued to term, four developed sustained hypertension (mean pressure 18 +/- 6 mm Hg above baseline), proteinuria, and moderate-to-severe glomerular endotheliosis. None of the controls had hypertension or proteinuria, but two had endotheliosis.

CONCLUSION

These observations confirm that a syndrome resembling preeclampsia can be produced by a reduction of lower aortic pressure, and they demonstrate that the associated hypertension is not an artifact of anesthesia. This model may prove useful in studying the pathophysiologic mechanisms of preeclampsia.