Diagnostic system for rapid and sensitive differential detection of pathogens

Naturally emerging and deliberately released pathogens demand new detection strategies to allow early recognition and containment. We describe a diagnostic system for rapid, sensitive, multiplex discrimination of microbial gene sequences and report its application for detecting 22 respiratory pathogens in clinical samples.

Contribution of bone marrow-derived cells to skin: collagen deposition and wound repair

The bone marrow provides inflammatory cells and endothelial progenitor cells to healing cutaneous wounds. To further explore the bone marrow contribution to skin and healing wounds, we used a chimeric mouse model in which the bone marrow from enhanced green fluorescent protein (EGFP) transgenic mice is transplanted into normal C57BL mice. We found that normal skin is a target organ for bone marrow-derived cells from both the hematopoietic and the mesenchymal stem cell pool. We present evidence that the bone marrow contribution to normal skin and the healing cutaneous wound is substantially greater than the previously recognized CD45+ subpopulation, where 15%-20% of the spindle-shaped dermal fibroblasts were bone marrow-derived (EGFP+). Furthermore, the bone marrow-derived cells were able to contract a collagen matrix and transcribe both collagen types I and III, whereas the skin-resident cells transcribed only collagen type I. Whereas endothelial progenitor cells were found early during the wound repair process, bone marrow-derived endothelial cells were not seen after epithelialization was complete. Our data show that wound healing involves local cutaneous cells for reconstituting the epidermis but distant bone marrow-derived cells and the adjacent uninjured dermal mesenchymal cells for reconstituting the dermal fibroblast population.

Superior mediastinal syndrome with Rowland-Payne syndrome: an unusual presentation of cervico-mediastinal neuroblastoma

A 5-month-old boy presented with superior mediastinal syndrome due to a large, unresectable cervico-mediastinal neuroblastoma. He had an unusual constellation of findings not previously reported in neuroblastoma: Horner syndrome, phrenic nerve palsy, and palsy of the ipsilateral recurrent laryngeal nerve. This constellation of findings in adult malignancies is termed the Rowland-Payne syndrome. The child required prolonged mechanical ventilation but responded to chemotherapy and is now free of tumor and completely recovered.

Does the Use of a Flap during Abdominoperineal Resection Decrease Pelvic Wound Morbidity?

We hypothesized that the use of muscle flaps, known as tissue transfer (TT), at the time of abdominoperineal resection (APR) reduces perineal wound complications. A restrospective review of patients undergoing an APR at the University of Washington (1984–2003) was conducted. Perineal wound complications and eventual wound healing were compared in patients with and without TT. Ninety-two patients (mean age, 56.6 years) underwent APR; 23.9 per cent (n = 22) had concurrent TT. Patients undergoing TT were more likely to have cancer (91% vs. 77%, P = 0.05) and radiation therapy (86% vs. 52%, P < 0.01). Operative times were nearly 2 hours longer in patients having TT (7.4 hours ± 2.5 hours vs. 5.6 hours ± 1.8 hours, P = 0.03), but lengths of stay were similar (13 ± 5.9 days vs. 12 ± 7.6 days, P = 0.5). Patients undergoing TT had a higher rate of all wound-healing complications (59% vs. 40%, P = 0.1) and major wound-healing complications (32% vs. 26%, P = 0.6). However, these differences were not statistically significant. No differences in major complications were identified in patients with and without preoperative radiation therapy (26% vs. 28%, P = 0.8). Fifteen per cent (n = 14) of all patients failed to heal wounds at 6 months, but only 9 per cent (n = 2) of patients undergoing TT failed to heal their wounds at 6 months compared with 17 per cent (n = 12) in the non-TT group ( P = 0.3). After controlling for important covariates, patients undergoing TT during an APR did not have a significantly lower rate of wound complications. The impact of TT on wound healing in patients with recurrent cancer and preoperative radiation therapy is suggestive of a benefit but requires prospective investigation.

Does the use of a flap during abdominoperineal resection decrease pelvic wound morbidity?

We hypothesized that the use of muscle flaps, known as tissue transfer (TT), at the time of abdominoperineal resection (APR) reduces perineal wound complications. A restrospective review of patients undergoing an APR at the University of Washington (1984-2003) was conducted. Perineal wound complications and eventual wound healing were compared in patients with and without TT. Ninety-two patients (mean age, 56.6 years) underwent APR; 23.9 per cent (n = 22) had concurrent TT. Patients undergoing TT were more likely to have cancer (91% vs. 77%, P = 0.05) and radiation therapy (86% vs. 52%, P < 0.01). Operative times were nearly 2 hours longer in patients having TT (7.4 hours +/- 2.5 hours vs. 5.6 hours +/- 1.8 hours, P = 0.03), but lengths of stay were similar (13 +/- 5.9 days vs. 12 +/- 7.6 days, P = 0.5). Patients undergoing TT had a higher rate of all wound-healing complications (59% vs. 40%, P = 0.1) and major wound-healing complications (32% vs. 26%, P = 0.6). However, these differences were not statistically significant. No differences in major complications were identified in patients with and without preoperative radiation therapy (26% vs. 28%, P = 0.8). Fifteen per cent (n = 14) of all patients failed to heal wounds at 6 months, but only 9 per cent (n = 2) of patients undergoing TT failed to heal their wounds at 6 months compared with 17 per cent (n = 12) in the non-TT group (P = 0.3). After controlling for important covariates, patients undergoing TT during an APR did not have a significantly lower rate of wound complications. The impact of TT on wound healing in patients with recurrent cancer and preoperative radiation therapy is suggestive of a benefit but requires prospective investigation.

Distal radio-ulnar joint subluxation following intramedullary nailing of the radius in a child

We describe a patient with fractures of both bones of the forearm in whom flexible intramedullary nail fixation of the radius alone led to ulnar malunion and a symptomatic distal radio-ulnar joint subluxation. This was successfully treated by ulnar osteotomy.

Distal radio-ulnar joint subluxation following intramedullary nailing of the radius in a child

We describe a patient with fractures of both bones of the forearm in whom flexible intramedullary nail fixation of the radius alone led to ulnar malunion and a symptomatic distal radio-ulnar joint subluxation. This was successfully treated by ulnar osteotomy.

Vascular malformations in muscles around the knee presenting as knee pain

Vascular malformations involving the muscles around the knee can be a cause of knee pain. We studied ten such cases. All underwent magnetic resonance (MR) imaging which confirmed the diagnosis. Eight cases underwent wide surgical excision of the lesion, histology of which showed a vascular malformation with predominantly venous element. There was no recurrence in any of the operated cases at the last follow-up. We believe that most of these lesions can be treated successfully by careful preoperative planning aided by MR imaging and a wide-open excision of the lesion.

Clinical profile and frequency of delta f508 mutation in Indian children with cystic fibrosis

OBJECTIVE

To document clinical profile of cystic fibrosis (CF) in Indian children and the prevalence of delta F508 mutation in these patients.

DESIGN

Observational study.

SETTING

Pediatric chest clinic in an urban tertiary care center in north India.

PERIOD OF STUDY

July 1995 to June 2002.

METHODS

Clinical features of 120 children diagnosed as CF by quantitative pilocarpine iontophoresis were recorded. A polymerase chain reaction based test for identification of delta F 508 mutation was performed on all children.

RESULTS

Out of 3500 new cases registered in Pediatric Chest Clinic during this period 120, (3.5%) children were diagnosed as CF. Origin of parents of patients traced from almost all the States of north India. Family history suggestive of CF was present in 41 (34%) and consanguinity in 19 (61%) patients. Common clinical manifestations at the time of presentation included recurrent or persistent pneumonia in 118 (98%), failure to thrive in 108 (90%), malabsorption in 96 (80%), history of meconium ileus in 10 (8%), and rectal prolapse was present in 16 (13%). History of salt craving, salty taste on kissing and skin rashes was present in 5 patients each. 49(41%) patients were severely malnourished. Nasal polyposis was present in 5 (4%) patients. Examination of chest revealed evidence of hyperinflation in 100 (83%), kyphosis 20 (17%), crepitations 110 (92%), wheezing 40 (25%) and bronchial breathing in 20 (17%) patients. Average clinical CF scores were 51 (95%; CI 20-80). 48 (40%) patients had a CF score of LT40. Pseudomonas spp was cultured from respiratory secretions of 51 (42%), Staphylococcus spp in 18 (15%), Klebsiella spp in 8 (7%) and Hemophilus influenzae in 2 (2%) patients. Delta F508 mutation was positive in 45 chromosomes out of 240 tested. Patients originated from Pakistan had more frequency of delta F508 mutations.

CONCLUSIONS

Cystic fibrosis does occur in Indian children; clinical features are classical. Diagnosis is often delayed and the disease is advanced in most patients at the time of diagnosis. Frequency of Delta F508 mutation is 19% i.e., less than that seen in Caucasian population. There is need to create awareness about occurrence of CF in Indian children.

Peripheral circulatory failure

Shock is a syndrome arising from any of several initiating causes, resulting in inadequate tissue perfusion. Untreated shock due to any cause can lead to irreversible cellular damage. Early diagnosis and intervention are, therefore, key to improved outcomes. In children, hypotension is not a sensitive marker for diagnosing peripheral circulatory failure. A detailed evaluation to assess perfusion particularly estimating capillary refill time and end organ perfusion is required. Septic shock is a complex condition with varying contribution of hypovolemia, cardiac dysfunction and distributive shock. Aggressive fluid therapy in the early stages is essential to recovery. Understanding the pathophysiology will help in judicious use of vasoactive drugs. Newer modalities of treatment for severe sepsis and septic shock still need evaluation in children.

The posterior cruciate ligament: an anthropometric study in Asians and evaluation of safe limits for bony tunnel creation during reconstruction

INTRODUCTION

Quantitative data regarding the dimensions of the posterior cruciate ligament (PCL) and its insertions have not been studied in Asians, and concerns have been raised regarding the danger of vascular injury when the bony tunnels are created during arthroscopically-assisted reconstruction.

MATERIALS AND METHODS

Ten male cadavers were used in this study, incorporating dissection and procedural arms. In the procedural arm, the path of the drill bit was tracked fluoroscopically as the tibial and femoral tunnels were created during simulated reconstructive surgery, and the effect of varying knee flexion angles was studied. Fluoroscopic images were analysed using specialised image processing software.

RESULTS

The mean length of the PCL at full extension was 37.7 +/- 1.9 mm, and the mean mid-substance width was 13.7 +/- 1.7 mm. The mean sagittal distance between the exit point of the tibial tunnel and the anterior surface of the popliteal artery, across all knee flexion positions, was merely 6.0 mm (range, 2.8 to 10.2 mm). This distance tended to increase with increasing knee flexion, but this was not statistically significant. The mean distance between the exit point of the femoral tunnel and the femoral artery was 51.1 mm (range, 42.1 to 59.0 mm).

CONCLUSIONS

The dimensions of the PCL and its insertions in Asians do not vary greatly from those reported for Western subjects. The distance from the exit point of the tibial tunnel to the popliteal artery is very small and, although this distance increases with increasing knee flexion, the improvement in the safety margin may neither be clinically nor statistically significant. The margin of safety for drilling of the femoral tunnel is much greater.

Wireless telemetry and Internet technologies for medical management: a Martian analogy

BACKGROUND

The NASA Haughton-Mars Project Base Camp on Devon Island, Canada (approximately 75 degrees north) was the site for transmission of vital signs from two "terranauts" (individuals who acted as Earthbound astronauts) back to the United States in (artificially delayed) real-time.

METHODS

The subjects became "physiologic ciphers" for status monitoring using readily available technologies that affordably captured and distributed vital signs to a variety of platforms. This study of nominal monitoring and simulated medical emergency used wireless technologies and the Internet.

RESULTS

Basic vital signs and images can be sent using wireless topologies and completely automated functions. Due to the lightweight transport requirements, existing low data rate connections can easily handle the volume of traffic.

CONCLUSIONS

Monitoring, the health of space travelers will be an important component for both low-Earth orbiting spacecraft and long-term missions to distant planets. However, terrestrial applications represent the primary application of such technologies because the home can be a remote and hazardous environment as well.

Usefulness of segmented trueFISP cardiac pulse sequence in evaluation of congenital and acquired adult cardiac abnormalities

OBJECTIVE

The purpose of this study is to compare ultrashort TR, segmented trueFISP (fast imaging with steady-state precession) cine MR imaging with segmented FLASH (fast low-angle shot) cine MR imaging for the detection and characterization of congenital and acquired adult cardiac abnormalities.

SUBJECTS AND METHODS

Twenty-five patients with known or clinically suspected cardiac abnormalities were imaged on a 1.5-T scanner. Valve plane movies were obtained in patients with suspected valve morphology or function abnormalities or whose horizontal long-axis images showed jets. For each patient, three radiologists independently compared corresponding matched cine FLASH and trueFISP movies for image quality in evaluating anatomy and function of the great vessels and heart. Image quality was rated on a five-point scale, and data were analyzed using both a Wilcoxon's signed rank test and a repeated-measures analysis of variance.

RESULTS

Image quality ratings of trueFISP and FLASH showed a statistically significant difference (F = 58.67; df = 1, 72; p < 0.0001), with the average rating for the trueFISP images being significantly higher (mean rating, 4.1 +/- 0.92) than that for the FLASH images (mean, 3.0 +/- 1.0). However, valve architecture in the aortic valves appeared to be better visualized and was more easily measured in valve plane images with FLASH. No statistically significant differences among the ratings of the interpreters (F = 0.018; df = 2, 72; p = 0.9821) were evident, and, therefore, no suggestion of bias was indicated (F = 0.775; df = 1, 2; p = 0.4645). TrueFISP yielded the correct diagnosis prospectively in 13 (100%) of 13 patients, whereas FLASH yielded the correct diagnosis in 12 (92%) of 13 patients.

CONCLUSION

TrueFISP images depict morphologic and functional abnormalities with greater clarity and provide greater diagnostic confidence than FLASH images-and in a fraction of the time. A specific exception is in the assessment of valve leaflet architecture and cross-sectional area calculation (i.e., bicuspid aortic valves); in these evaluations, FLASH maintains a complementary diagnostic imaging role.

Vertebral mass resulting from a chronic-contained rupture of an abdominal aortic aneurysm repair graft

We describe a case of a 63-year-old man with chronic-contained rupture of an abdominal aortic aneurysm at the site of prior graft repair of the aneurysm. Initially misinterpreted as osteomyelitis on the basis of CT findings, this chronic-contained rupture of the abdominal aorta eroding the vertebrae was preoperatively diagnosed at MR imaging and confirmed at surgery. A conventional angiogram failed to show the pseudoaneurysm. Owing to a major difference in the management of a contained aortic aneurysm rupture versus that for osteomyelitis, MR imaging with CT or MR angiography is recommended before any operative or invasive procedure.

Kynurenine pathway metabolism in human astrocytes: a paradox for neuronal protection

There is good evidence that the kynurenine pathway (KP) and one of its products, quinolinic acid (QUIN), play a role in the pathogenesis of neurological diseases, in particular AIDS dementia complex. Although QUIN has been shown to be produced in neurotoxic concentrations by macrophages and microglia, the role of astrocytes in QUIN production is controversial. Using cytokine-stimulated cultures of human astrocytes, we assayed key enzymes and products of the KP. We found that human astrocytes lack kynurenine hydroxylase so that large amounts of kynurenine and the QUIN antagonist kynurenic acid were produced. However, the amounts of QUIN that were synthesized were subsequently completely degraded. We then showed that kynurenine in concentrations comparable with those produced by astrocytes led to significant production of QUIN by macrophages. These results suggest that astrocytes alone are neuroprotective by minimizing QUIN production and maximizing synthesis of kynurenic acid. However, it is likely that, in the presence of macrophages and/or microglia, astrocytes become indirectly neurotoxic by the production of large concentrations of kynurenine that can be secondarily metabolized by neighbouring or infiltrating monocytic cells to form the neurotoxin QUIN.

Impact of varying transmission bandwidth on image quality

The objective of this paper is to determine the effect of varying transmission bandwidth on image quality in laparoscopic surgery. Surgeons located in remote operating rooms connected through a telemedicine link must be able to transmit medical images for interaction. Image clarity and color fidelity are of critical importance in telementoring laparoscopic procedures. The clarity of laparoscopic images was measured by assessing visual acuity using a video image of a Snellen eye chart obtained with standard diameter laparoscopes (2, 5, and 10 mm). The clarity of the local image was then compared to that of remote images transmitted using various bandwidths and connection protocols [33.6 Kbps POTS (IP), 128 Kbps ISDN, 384 Kbps ISDN, 10 Mbps LAN (IP)]. The laparoscopes were subsequently used to view standard color placards. These color images were sent via similar transmission bandwidths and connection protocols. The local and remote images of the color placards were compared to determine the effect of the transmission protocols on color fidelity. Use of laparoscopes of different diameter does not significantly affect image clarity or color fidelity as long as the laparoscopes are positioned at their optimal working distance. Decreasing transmission bandwidth does not significantly affect image clarity or color fidelity when sufficient time is allowed for the algorithms to redraw the remote image. Remote telementoring of laparoscopic procedures is feasible. However, low bandwidth connections require slow and/or temporarily stopped camera movements for the quality of the remote video image to approximate that of the local video image.

Dynamic actin polymerization drives T cell receptor-induced spreading: a role for the signal transduction adaptor LAT

T cell activation induces functional changes in cell shape and cytoskeletal architecture. To facilitate the collection of dynamic, high-resolution images of activated T cells, we plated T cells on coverslips coated with antibodies to the T cell receptor (TCR). Using these images, we were able to quantitate the morphological responses of individual cells over time. Here, we show that TCR engagement triggers the formation and expansion of contacts bounded by continuously remodeled actin-rich rings. These processes are associated with the extension of lamellipodia and require actin polymerization, tyrosine kinase activation, cytoplasmic calcium increases, and LAT, an important hematopoietic adaptor. In addition, the maintenance of the resulting contact requires sustained calcium influxes, an intact microtubule cytoskeleton, and functional LAT.