(1)H NMR spectroscopy in the diagnosis of Pseudomonas aeruginosa-induced urinary tract infection

The utility of (1)H NMR spectroscopy is suggested and demonstrated for the diagnosis of Pseudomonas aeruginosa in urinary tract infection (UTI). The specific property of P. aeruginosa of metabolizing nicotinic acid to 6-hydroxynicotinic acid (6-OHNA) is exploited. The quantity of 6-OHNA produced correlates well with the viable bacterial count. Other common bacteria causing UTI such as Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, Acinetobacter baumanii, Proteus mirabilis, Citrobacter frundii, Enterococcus faecalis, Streptococcus gp B and Staphylococcus aureus do not metabolize nicotinic acid under similar conditions. The method provides a single-step documentation of P. aeruginosa qualitatively as well as quantitatively. The NMR method is demonstrated on urine samples from 30 patients with UTI caused by P. aeruginosa.

Renal replacement therapy options from an Indian perspective: Dialysis versus transplantation

In developing countries such as India, the management of end-stage renal disease (ESRD) is largely guided by economic considerations. In the absence of health insurance plans, fewer than 10% of all patients receive renal replacement therapy (RRT). Hemodialysis (HD) is mainly a short-term measure to support ESRD patients prior to transplant. Infections are common in dialysis patients. The majority of patients starting HD die or are forced to abandon treatment because of cost constraints within the first 3 months. The cost of peritoneal dialysis (PD) is two times higher than that of HD, fewer than 2% of patients are started on PD. Among the three RRT options available, renal transplant is the preferred mode, as it is most cost-effective and provides a better quality of life. But due to financial constraints and nonavailability of organs, only about 5% of ESRD patients undergo transplant surgery. Though the removal of organs from brain-dead patients has been legalized, the concept of donation of organs from deceased donors has not received adequate social sanction. Only 2% of all transplants are performed from deceased donors. Due to limited access to RRT, the ideal approach should be to reduce the incidence of ESRD and attempt preventive measures. Preemptive transplant, reducing the duration of dialysis prior to transplant, use of immunosuppression for only up to 1 year, and availability of more deceased donor organs may be helpful to make RRT options within the reach of the common man.

1H NMR spectroscopic method for diagnosis of malabsorption syndrome: a pilot study

Despite its well-documented limitations, colorimetry has been commonly used for the d-xylose test in the diagnosis of malabsorption syndrome (MAS). With a possibility of overcoming its limitations, the use of (1)H NMR spectroscopy for D-xylose test is explored herein. Urine samples from 35 adults with suspected MAS were obtained before and after oral ingestion of D-xylose. The diagnosis of MAS was based on fecal fat (72 h excretion using Van de Kamer's technique, normal < 7 g/24 h and/or Sudan III stain of spot stool specimen, normal<or=10 droplets/high power field) and/or endoscopic duodenal biopsy. Urinary excretion of D-xylose over 5 h after consumption of 5 g D-xylose, using both colorimetry and NMR was compared (normal>or=1 g/5 g/5 h). In vitro experiments on the standard specimens of D-xylose were also performed independently using both methods. Colorimetry showed a lower value for the quantity of D-xylose excreted in urine than NMR [median 0.73 (0.17-1.89 g) vs 1.37 (0.17-3.23 g), respectively; p<0.0001, Wilcoxon's signed ranks test]. Colorimetry and NMR correctly diagnosed 11/12 and 10/12 (p=N.S.) patients with MAS and 14/23 and 20/23 (p<0.05) without MAS, respectively. Sensitivity and specificity of colorimetry and NMR were 91.6 and 60.7% vs 83.3 and 86.9%, respectively. In in vitro experiments, the values obtained for standard xylose using NMR showed a maximum error of 7%, whereas the colorimetric method showed 20%. The NMR method is simple and may be more accurate for the D-xylose absorption test. Colorimetry was found to be inferior as compared with NMR due to its low specificity.

Finite element analysis of a femoral retrograde intramedullary nail subject to gait loading

Intramedullary nails are routinely used in the treatment of fractures of the femur. While their effectiveness has been demonstrated clinically, a number of complications, including bone refracture and implant failure, persist. This paper presents novel three-dimensional finite element (FE) models, at four stages of gait, of: (i) a realistic femur analogue known as third generation composite bone, and (ii) a system consisting of an intramedullary nail implanted in the femur of (i). A comparison of experimentally measured strains on the surface of the femur with those predicted by the FE model revealed good agreement. The models were then used to identify implant/bone load sharing patterns, and areas of stress concentration in both the intramedullary nail and the bone, when statically locked by one or two screws at either end. The results of this study can be used to guide future implant design and surgical procedure.

Stone composition, metabolic profile and the presence of the gut-inhabiting bacterium Oxalobacter formigenes as risk factors for renal stone formation

OBJECTIVE

To examine stone composition, metabolic evaluation and colonization of Oxalobacter formigenes as risk factors for renal stone formation.

SUBJECTS AND METHODS

Eighty patients with renal stones and 70 healthy controls were enrolled in the study. Of the 80 patients, 48 were first-time stone formers (FSF) and 32 were 'recurrent' stone formers (RSF), recurrent indicating 2 or more episodes of stone formation. Stone analysis by X-ray crystallography, 24-hour urine metabolic profile and detection of O. formigenes-specific DNA by PCR were performed for each patient. Detection of O. formigenes was also performed on 45 and urinary metabolic profile on an additional 25 controls.

RESULTS

Calcium oxalate monohydrate was the major component of stones, hyperoxaluria and hypocitraturia were the most common urinary abnormalities in the 80 patients, 46% of RSF patients had hypercalciuria. Urinary abnormalities were far less frequent in the controls, with the exception of hypocitraturia (40%). Of the urinary metabolites, only calcium levels were significantly different (p < 0.05) between FSF (6.50 +/- 4.08 mmol/24 h) and RSF (8.21 +/- 5.26 mmol/24 h) patients. Colonization of O. formigenes was higher in controls (62.2%) than in FSF (33.3%) or RSF (28%) patients, it was least in patients with more than 4 episodes (7%) of stone formation.

CONCLUSION

The findings indicate that lack of colonization of O. formigenes may be an important risk factor for recurrence of stone formation (calcium oxalate monohydrate).

Emergency coronary stenting of unprotected critical left main coronary artery stenosis in acute myocardial infarction and cardiogenic shock

In the setting of acute myocardial infarction (MI) and cardiogenic shock in patients with significant unprotected left main coronary artery (LMCA) disease, treatment options are limited. In this report of a patient presenting in cardiogenic shock secondary to acute MI with critical LMCA stenosis, percutaneous coronary intervention with intra-aortic balloon pump support proved life saving.

High and low pressure irrigation in contaminated wounds with exposed bone

BACKGROUND

Irrigation and debridement are essential in the initial management of traumatic wounds. The relative efficicacy of low pressure irrigation compared with high pressure irrigation remains unclear.

AIMS

The purpose of this study was to examine the time dependent efficacy of both high and low pressure lavage in removing adherent bacteria from traumatic wounds with exposed bone.

METHODS

Using an in-vivo model, we created bilateral Staphylococcus aureus contaminated femoral wounds in 30 mice. The wounds were incubated for 1 to 10 hours and lavaged with either high (70 psi) or low pressure lavage (1-2 psi). The mean colony forming units of bacteria were compared between groups at each time point.

RESULTS

High and low pressure lavage were effective in removing adherent bacteria from contaminated wounds up to 8 hours and 4 hours, respectively. High pressure lavage was more effective than low pressure at every time point.

CONCLUSION

The efficacy of low pressure lavage in wounds with exposed bone is questionable when irrigation is delayed beyond 4 hours.

Predictors of in-hospital mortality following operative management of hip fractures

OBJECTIVE

To identify predictors of in-hospital mortality and hospital stay following hip fractures.

DESIGN

Retrospective cohort study of 185 consecutive patients.

SETTING

Tertiary Care University Hospital.

PARTICIPANTS

Individuals requiring operative treatment of a proximal femoral fracture excluding those individuals < 50 years old, with femoral head or subtrochanteric fractures, and significant co-morbidity.

OUTCOMES

In-hospital mortality and length of hospital stay (days).

RESULTS

116 patients met the inclusion criteria. Predictors of in-hospital mortality from logistic regression analysis included male gender (odds ratio with 95% CI: 5.5, 1.5-20.5), admission from a long term care facility (5.5, 1.4-22.6), age greater than 90 years (4.5, 0.9-22.1), and living at home with support (0.2, 0.03-0.9). Predictors of hospital stay from multivariate regression analysis in order of magnitude included presence of a post-operative complication (odds ratio with 95% CI: 14.1, 4.7-44), living at home with support (3.4, 1.3-8.9) and older age (> 85 years) (2.7, 1.0-7.3). Moreover, confusion, urinary tract infections and decubitus ulcers accounted for greater than 50% of all complications encountered. A trend between the number of positive predictors and length of hospital stay was observed.

CONCLUSIONS

Elderly individuals admitted from a long term care facility are at high risk of mortality following operative fixation of hip fractures. Early recognition and aggressive management of post-operative complications such as confusion, urinary tract infections and decubitus ulcers through careful patient monitoring may decrease hospital stays in those that survive.

A new dimension of 1H-NMR spectroscopy in assessment of liver graft dysfunction

High-resolution 1H-NMR spectroscopy of serum and urine samples of an 11-year-old male living related orthotopic liver transplant recipient is reported. Serum glutamine increased to abnormal levels along with simultaneous abnormal excretion of urinary glutamine post-transplantation. High levels of glutamine in both blood and urine and concomitant reduced urea levels in urine were found to be evidence of impairment in urea cycle and compatible with persistently abnormal graft function. Thus glutamine levels in serum and urine, and urea in the urine as observed by 1H-NMR spectroscopy highlight their important roles in monitoring liver graft function; increased glutamine levels lead to brain damage, if untreated.

Substitution urethroplasty for anterior urethral strictures: a critical appraisal of various techniques

OBJECTIVE

To retrospectively compare the outcome of various techniques of substitution urethroplasty.

PATIENTS AND METHODS

Between 1989 and 2000, 109 patients (mean age 39.5 years) underwent substitution urethroplasty for recurrent anterior urethral strictures. Between 1989 and 1995 the procedure was by ventral placement of free grafts (bladder mucosa, buccal mucosa, penile skin) or penile skin flaps. From 1995 onwards the flaps and grafts (buccal mucosa) were applied either ventrally or dorsally. Stricture recurrence and the complications associated with each technique were compared.

RESULTS

Ventral onlay repairs were associated with a higher incidence of complications than dorsal repairs, e.g. postvoid dribbling (39% vs 23%, P = 0.01), ejaculatory dysfunction (20% vs 5%, P = 0.03) and flap/graft pseudo-diverticulum or out-pouching (26% vs 2.6%, P = 0.01). Superficial penile skin necrosis was significantly more common with the use of penile skin flaps than with free grafts. There was no significant difference in stricture recurrence, erectile dysfunction and residual penile deformity among the various techniques.

CONCLUSIONS

Dorsal free graft/flap onlay urethroplasty gives better results than ventrally placed free grafts/flaps. Dorsal onlay buccal mucosal urethroplasty is a versatile procedure and associated with fewer complications than other substitution methods.

Epidural analgesia for pain relief following hip or knee replacement

BACKGROUND

Hip and knee replacement are common operative procedures to improve mobility and quality of life. Adequate pain relief is essential in the postoperative period to enable ambulation and initiation of physiotherapy. Lumbar epidural analgesia is a common modality for pain relief following these procedures. However, there is no systematic review of the evidence comparing the efficacy of epidural analgesia with other postoperative analgesic modalities. As the use of epidural analgesia may delay the initiation of anticoagulant thromboprophylaxis due to the potential risk of epidural hematoma, a synthesis of the evidence is necessary to determine whether or not alternative analgesic modalities are worse, equivalent, or better than epidural analgesia.

OBJECTIVES

Our objective is to answer the question: "Is lumbar epidural analgesia more efficacious than systemic analgesia or long-acting spinal analgesia for postoperative pain relief in patients after elective hip or knee replacement?"

SEARCH STRATEGY

MEDLINE, EMBASE, CINAHL, LILACS, and the Cochrane Controlled Trials Register were searched from their inception to June 2001. Reference lists of review articles and included studies were also reviewed for additional citations.

SELECTION CRITERIA

A study was included if it was a randomized or pseudo randomized controlled clinical trial of patients undergoing hip or knee replacement, in which postoperative lumbar epidural analgesia was compared to other methods for pain relief. Study selection was performed unblinded in duplicate.

DATA COLLECTION AND ANALYSIS

Data were collected unblinded in duplicate. Information on the patients, methods, interventions, outcomes (pain relief, postoperative function, length of stay) and adverse events were recorded. Methodological quality was assessed using a validated 5-point scale. Meta-analysis was conducted when sufficient data existed from two or more studies. Heterogeneity testing was performed using the Breslow-Day method. The fixed effects model was used unless heterogeneity was present, in which case, a random effects model was used. Continuous data were summarized as weighted mean differences (WMD) or standardized mean differences (SMD) with 95% confidence intervals (CI). Dichotomous data were summarized as odds ratios (OR) and numbers-needed-to-treat (NNT) or numbers-needed-to-harm (NNH) with their respective 95% CI. Graphical representation of continuous data used the MetaView program.

MAIN RESULTS

In the first four to six hours after surgery, patients receiving epidural analgesia had less pain at rest, based on visual analog scores (VAS), than patients receiving systemic analgesia (SMD -0.77; 95% CI -1.24 to -0.31). This effect was not statistically significant by 18 to 24 hours (SMD -0.29; 95% CI -0.73 to 0.16). These observations were based only on studies evaluating populations consisting of total knee replacements alone or mixed populations of total hip or total knee replacements. For pain relief with movement after surgery, patients receiving epidural analgesia reported lower pain scores than patients receiving systemic analgesia in all four studies examining these outcomes. The choice of epidural agents may also influence the extent to which epidural analgesia differs from systemic analgesia. The differences between epidural analgesia and systemic analgesia in the frequency of nausea and vomiting (OR 0.95; 95% CI 0.60 to 1.49) or depression of breathing (OR 1.07; 95% CI 0.45 to 2.54) were not statistically significant. Sedation occurred less frequently with epidural analgesia (OR 0.30; 95% CI 0.09 to 0.97) with a number-needed-to-harm of 7.7 (95% CI 3.5 to 42.0) patients for the systemic analgesia group. Retention of urine (OR 3.50, 95% CI 1.63 to 7.51; NNH 4.5, 95% CI 2.3 to 12.2), itching (OR 4.74, 95% CI 1.76 to 12.78; NNH 6.8, 95% CI 4.4 to 15.8), and low blood pressure (OR 2.78, 95% CI 1.15 to 6.72; NNH 6.7, 95% CI 3.5 to 103) were more frequent with epidural analgesia compared to systemic analgesia. There were insufficient numbers to draw conclusions on the edural analgesia compared to systemic analgesia. There were insufficient numbers to draw conclusions on the effect of epidural analgesia on serious postoperative complications, functional outcomes, or length of hospital stay.

REVIEWER'S CONCLUSIONS

Epidural analgesia may be useful for postoperative pain relief following major lower limb joint replacements. However, the benefits may be limited to the early (four to six hours) postoperative period. An epidural infusion of local anesthetic or local anesthetic-narcotic mixture may be better than epidural narcotic alone. The magnitude of pain relief must be weighed against the frequency of adverse events. The current evidence is insufficient to draw conclusions on the frequency of rare complications from epidural analgesia, postoperative morbidity or mortality, functional outcomes, or length of hospital stay.

High-pressure irrigation increases adipocyte-like cells at the expense of osteoblasts in vitro

High-pressure lavage produces greater visible damage to bone at a macroscopic and microscopic level when compared with low-pressure lavage and can result in delay in the healing of fractures. Osteoblasts and adipocytes are derived from mesenchymal stem cells. Conditions which lead to bone loss often involve a switch from the osteoblast to adipocyte lineage. We have therefore examined the effect of high- and low-pressure irrigation on the differentiation of adipocytes.

Calvaria-derived bone cells were exposed to either low-pressure or high-pressure irrigation with normal saline. After 14 days the cells were fixed and the osteoblasts and adipocytes quantified using Oil Red O to stain cytoplasmic lipid droplets (triglycerides) in the cells. Osteoblasts were quantified using a commercially available alkaline-phosphatase staining assay.

A standard quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed. Messenger RNA levels for osteocalcin, a marker of osteoblasts, and PPARγ2, a marker of adipocytes, were measured. High-pressure lavage resulted in an increase in adipogenesis of 50% when compared with low-pressure lavage.

Our findings suggest that high-pressure lavage may promote differentiation of mesenchymal stem cells towards the adipoctye lineage. This may have clinical significance in the development of delayed and nonunion after treatment of fractures of long bones.

Treatment of symptomatic polycystic liver disease with resection-fenestration

Polycystic liver disease with severe symptoms is difficult to treat. We report a 35-year-old man with advanced disease, who had a successful outcome after resection and fenestration.

Laparoscopic surgery for reflux esophagitis and paraesophageal hernia

BACKGROUND

Laparoscopic surgery has become the standard for treatment of several abdominal diseases. We analyzed our data on laparoscopic treatment of reflux esophagitis and paraesophageal hernia.

METHODS

Twenty patients (mean age 61 y; 14 men) - 18 with reflux esophagitis and sliding hiatus hernia, and two with paraesophageal and sliding hernia - were operated on using laparoscopy between March 1999 and March 2001. All patients were investigated by upper GI endoscopy, barium study and routine pre-operative work-up. Nineteen patients underwent a modified Nissen fundal wrap along with repair of the diaphragmatic crura; one patient had only crural repair with no fundal wrap.

RESULTS

All procedures were completed laparoscopically. The mean operating time was 140 min (range 90 to 240). Eighteen patients were discharged on the third postoperative day and two on the fifth day. One patient had perforation of intrathoracic part of the esophagus during passage of an esophageal bougie; he presented with empyema 10 days after discharge and was treated by intercostal drainage. There were no other complications. All patients have been followed up on an outpatient basis for 3 months to 2 years. All are presently off acid-suppressive therapy. Seventeen patients are free of symptoms; two patients have gas bloat-like symptoms and one has occasional grade I dysphagia.

CONCLUSIONS

Laparosopic surgery is a safe and effective method of treating esophagitis and paraesophageal hernia.

Role of Oxalobacter formigenes in calcium oxalate stone disease: a study from North India

OBJECTIVE

The present study was performed to detect the presence of an oxalate degrading bacteria Oxalobacter formigenes in the GI tract of calcium oxalate stone patients and normal individuals from North India. Furthermore, the possible relationship of this bacterium with number of stone episodes in this part of the world was also studied. The correlation of the presence or absence of O. formigenes with the urinary oxalate levels was evaluated.

METHODS

DNA was extracted from the stool samples of 63 calcium oxalate stone formers and 40 normal individuals. Polymerase chain reaction (PCR) was performed using genus specific primers for O. formigenes. The presence of which was confirmed by Southern blotting. Urinary oxalate levels were tested in each patient.

RESULTS

As shown by PCR and Southern blotting, O. formigenes was present in 65% of normal individuals and in 30% of calcium oxalate stone formers. In patients with three or greater than three stone episodes colonies were present only in 5.6% of patients. Oxalate excretion was less in patients colonized with O. formigenes as compared to those with no colonization.

CONCLUSION

In North Indian population the absence of O. formigenes can lead to a significant increase in the risk of absorptive hyperoxaluria and resultant recurrent calcium oxalate stone episodes.

Interobserver and intraobserver variation in the assessment of the healing of tibial fractures after intramedullary fixation

The reliability of the radiological assessment of the healing of tibial fractures remains undetermined. We examined the inter- and intraobserver agreement of the healing of such fractures among four orthopaedic trauma surgeons who, on two separate occasions eight weeks apart, independently assessed the radiographs of 30 patients with fractures of the tibial shaft which had been treated by intramedullary fixation. The radiographs were selected from a database to represent fractures at various stages of healing. For each radiograph, the surgeon scored the degree of union, quantified the number of cortices bridged by callus or with a visible fracture line, described the extent and quality of the callus, and provided an overall rating of healing. The interobserver chance-corrected agreement using a quadratically weighted kappa (kappa) statistic in which values of 0.61 to 0.80 represented substantial agreement were as follows: radiological union scale (kappa= 0.60); number of cortices bridged by callus (kappa = 0.75); number of cortices with a visible fracture line (kappa= 0.70); the extent of the callus (kappa = 0.57); and general impression of fracture healing (kappa = 0.67). The intraobserver agreement of the overall impression of healing (kappa = 0.89) and the number of cortices bridged by callus (kappa = 0.82) or with a visible fracture line (kappa = 0.83) was almost perfect. There are no validated scales which allow surgeons to grade fracture healing radiologically. Among those examined, the number of cortices bridged by bone appears to be a reliable, and easily measured radiological variable to assess the healing of fractures after intramedullary fixation.