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Biomedical subjects

Senthil Kumar

Publications and source records attributed to Senthil Kumar.

10 recordsLinked to original sources
PubMed2006

IL-6 and IL-12 specifically regulate the expression of Rab5 and Rab7 via distinct signaling pathways.

Recent studies have shown that phagosome maturation depends on the balance between pro-inflammatory and anti-inflammatory cytokines, indicating that cytokine modulates phagosome maturation. However, the mechanism of cytokine-mediated modulation of intracellular trafficking remains to be elucidated. Here, we have shown that treatment of macrophages with IL-6 specifically induce the expression of Rab5 through the activation of extracellular signal-regulated kinase, whereas IL-12 exclusively upregulate the expression of Rab7 through the activation of p38 MAPK. We have cloned the 5'-flanking regions of the rab5c or rab7 into the promoterless reporter vector. Our results have shown that cells transfected with rab5c chimera are transactivated by IL-6, and IL-12 specifically transactivates cells containing rab7 chimera. Moreover, our results also show that IL-12 induces lysosomal transport, whereas IL-6 stimulates the fusion between early compartments in macrophages and accordingly modulates Salmonella trafficking and survival in macrophages. This is the first demonstration showing that cytokine differentially regulates endocytic trafficking by controlling the expression of appropriate Rab GTPase, and provides insight into the mechanism of cytokine-mediated regulation of intracellular trafficking.

5' Flanking Region↗
PubMed2006

Rabbit articular cartilage defects treated by allogenic chondrocyte transplantation.

Articular cartilage defects have a poor capacity for repair. Most of the current treatment options result in the formation of fibro-cartilage, which is functionally inferior to normal hyaline articular cartilage. We studied the effectiveness of allogenic chondrocyte transplantation for focal articular cartilage defects in rabbits. Chondrocytes were cultured in vitro from cartilage harvested from the knee joints of a New Zealand White rabbit. A 3 mm defect was created in the articular cartilage of both knees in other rabbits. The cultured allogenic chondrocytes were transplanted into the defect in the right knees and closed with a periosteal flap, while the defects in the left knees served as controls and were closed with a periosteal flap alone, without chondrocytes. Healing of the defects was assessed at 12 weeks by histological studies. Allogenic chondrocyte transplantation significantly increased the amount of newly formed repair tissue (P=0.04) compared with that found in the control knees. The histological quality score of the repair tissue was significantly better (P=0.05), with more hyaline characteristics in the knees treated with allogenic chondrocytes than in the control knees. Articular cartilage defects treated with allogenic chondrocyte transplantation result in better repair tissue formation with hyaline characteristics than those in control knees.

Animals↗
PubMed2006

Head-at-risk signs in Legg-Calvé-Perthes disease: poor inter- and intra-observer reliability.

BACKGROUND: The head-at-risk signs are used as prognostic indicators in Legg-Calvé-Perthes disease. These signs have been assessed only once regarding inter-observer reliability, however. Intra-observer reliability seems not to have been studied to date. METHOD: 76 anteroposterior pelvic radiographs of unilateral Legg-Calvé-Perthes disease were assessed by 5 observers on 2 occasions, in order to assess the inter- and intra-observer reliability in identifying head-at-risk signs. The observers included 1 consultant pediatric orthopaedic surgeon, 1 consultant radiologist, 2 specialist registrars and 1 senior house officer. Inter- and intra-observer reliabilities were assessed using the kappa coefficient. RESULTS: The intra-observer reliability was good for lateral subluxation and metaphyseal cystic changes, moderate for lateral calcification, and fair for Gage's sign and horizontal growth plate. The inter-observer reliability was moderate for lateral subluxation, fair for lateral calcification and metaphyseal cystic changes, and slight for Gage's sign and horizontal growth plate. INTERPRETATION: There was considerable variation in the diagnosis of the head-at-risk signs between observers. This makes the classification difficult to use in clinical practice.

Calcinosis↗
PubMed2006

The uncemented isoelastic/isotitan total hip arthroplasty. A 10-15 years follow-up with bone mineral density evaluation.

The present study analyses the long-term outcome of isoelastic hip prostheses and their influence on the extent of periprosthetic bone remodeling. Ninety-two patients (102 hips) with Isoelastic/Isotitan uncemented total hip arthroplasty were evaluated after an average of 13.4 years. The average age of patients at surgery was 42.5 years. The clinical outcome was assessed based on the Harris hip score, complications and thigh pain. Bone mineral density (BMD) of the proximal femur in the seven Gruen zones was evaluated by dual-energy X-ray absorptiometry (DEXA) scans with the contralateral hip serving as a control. The average Harris hip score at the most recent follow-up was 72 points, with 72 hips (70%) rating completely pain free. Eight stems required revision whereas none of the cups showed any evidence of loosening. The change in the mean BMD values between the femora on the operated side and the contralateral femora averaged 15% for all zones Although the isoelastic stems are no longer used owing to their high loosening rate, it appears that this prosthesis preserved periprosthetic bone better than reported for cemented or uncemented metallic implants. Besides, the provision of a titanium coating on the isoelastic stem, comparable to that on the RM cup, would presumably have improved its long-term fixation by encouraging bony ongrowth.

Absorptiometry, Photon↗
PubMed2005

An alternative port for use in hand-assisted laparoscopic surgery: a design using a stoma ring and a glove.

Hand-assisted laparoscopic surgery (HALS) has widened the range of laparoscopic surgery. An appropriate port allowing the passage of the hand while maintaining pneumoperitoneum is mandatory for HALS to be performed. Commercially available ports are expensive and may not be universally available. An inexpensive 2-component port using the flange of a stoma appliance and a glove, which could be readily assembled at short notice, is described.

Gloves, Protective↗
PubMed2005

Effects of perioperative hypothermia and warming in surgical practice.

Perioperative hypothermia is common and adversely affects clinical outcomes due to its effect on a range of homeostatic functions. Many of these adverse consequences are preventable by the use of warming techniques. A literature search was conducted to identify relevant published articles on perioperative hypothermia and warming. The databases searched include MEDLINE (1966 to February 2005), EMBASE (1974 to February 2005), CINAHL, the Cochrane library and the health technology assessment database. Reference lists of key articles were also searched. The primary beneficial effects of warming are mediated through increased blood flow and oxygen tension at tissue level. Reduction in wound infection, blood loss and perioperative pain with warming is promising. However, more evidence from good-quality prospective randomised controlled trials is needed to evaluate the role of warming in improving overall morbidity, mortality and hospital stay as well as to clarify its role as an adjunct to resuscitation and during the pre-hospital transport phase of critically ill patients. Awareness of the risks of perioperative hypothermia is the key to prevention. Achieving normothermia throughout the patient's journey is a worthwhile goal in surgical patients.

Body Temperature Regulation↗
PubMed2002

Intermittent pneumatic compression as an adjuvant therapy in venous ulcer disease.

Despite improvements in healing rates venous ulcer disease still carries significant morbidity and cost. Any therapy that further improves healing rates is worthy of consideration. The recognised effects of intermittent pneumatic compression (IPC) on both arterial and venous circulation suggest that its use may confer significant benefits to venous ulcer healing. This study investigates the potential additive effects of adjuvant IPC on the healing and subsequent prevention of venous ulcers. Some improvement in the rate of healing in venous ulcers is noted. These findings are set against a background of very high healing rates in both treatment and control groups. No benefit is seen to accrue if IPC is used as an adjuvant therapy to help prevent recurrence of ulcers although the study period is very short.

Aged↗
PubMed2002

The effects of intermittent pneumatic compression on the arterial and venous system of the lower limb: a review.

A better understanding of lower limb haemodynamics and the effects of intermittent pneumatic compression on the lower limb has led to an increasing awareness of the potential value of intermittent pneumatic compression in both venous and arterial disease. Intermittent pneumatic compression can be used in both the primary and secondary care settings, with its advantages being further enhanced by excellent patient compliance and very low rate of complications. Intermittent pneumatic compression has a proven role in the prophylaxis of deep vein thrombosis and there is some evidence that it is a useful adjunct in the management of venous ulcer disease. With laboratory and more recent clinical studies demonstrating augmentation of arterial inflow with intermittent pneumatic compression, its use in arterial diseases is being increasingly explored. Further studies are needed to define the precise role of intermittent pneumatic compression in arterial disease but any treatment regimen which reduces the need for referral or intervention in the claudicant or critically ischaemic limb will be a valuable addition to those managing arterial disease.

Equipment Design↗