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Biomedical subjects

H Sandhu

Publications and source records attributed to H Sandhu.

16 recordsLinked to original sources
PubMed2003

The incidence of cement extrusion from the acetabulum in total hip arthroplasty.

Acetabular cement extrusion (CE) is a common finding after total hip arthroplasty, but the incidence is unclear from the literature, and there is no accepted way of measuring it. We report a retrospective observational study of 100 patients (25 consecutive patients from each of 4 consultants, 112 hips) to determine the site and incidence of CE on postoperative radiographs, and to measure its area and the maximum distance of the extruded cement from the edge of the cement mantle. We found that 50 of 112 (44.6%) hips showed evidence of CE, with a 15.2% incidence of CE > 200 mm(2).

Acetabulum↗
PubMed2002

No smoke without fire--simple recommendations to avoid arthroscopic burns.

Despite anecdotal stories, the potential of the arthroscope tip or the light cable end to cause thermal burns to the surgical drapes and to patients has not been investigated in orthopaedic surgery. This study shows that the arthroscopic tip registering a temperature of 41.9 degrees C, is unlikely to cause skin burns but causes singeing of drapes without combustion. The light cable end registers a temperature of 101 degrees C with the potential for causing skin burns. It has been demonstrated to cause combustion of disposable arthroscopic drapes within seconds at a distance of 0.5 cm. It is recommended that the light source should be switched on only after the light cable has been connected to the arthroscope. The light cable end must not rest on the drapes once the light source has been switched on, as thermal burns will occur within seconds. A retractable shield of 2.5 cm fitted to the light cable end may virtually avoid the potential for combustion.

Arthroscopy↗
PubMed2001

An unexpected outcome during testing of commercially available demineralized bone graft materials: how safe are the nonallograft components?

STUDY DESIGN: Radiographic and histologic analyses of commercially available bone graft materials were performed. OBJECTIVE: To compare the osteoinductive efficacy of commercially available demineralized bone matrix material. SUMMARY OF BACKGROUND DATA: The relative in vivo bone formation and toxicology of the nonallograft components the make up various commercially available demineralized bone matrix products are not known. METHODS: An in vivo bone formation model was used in 30 athymic rats. Six different bone grafting materials were tested in subcutaneous and intermuscular locations. After 4 weeks, radiographic and histologic testing of bone formation was performed. RESULTS: Eight of nine rats implanted with Grafton demineralized bone matrix products died 1 to 4 days after implantation of the bone graft material. None of the remaining 10 animals implanted with the four other grafting materials died. The experiment was modified and completed with a lower dose of bone graft material. Pathologic analysis indicated that the cause of death was hemorrhagic necrosis of the kidneys, most likely caused by a toxic effect on the glomeruli and tubules. A possible causative factor may have been the glycerol in the graft material. CONCLUSIONS: Although the volume of Grafton product per kilogram of body weight used in this study was approximately eight times the maximum volume used in humans, the authors believe that this data must be reported because this product is used substantially in clinical settings. In addition, the osteoinductive performance and relative safety of the nonallograft components in all commercially available demineralized bone grafts are not known.

Animals↗
PubMed2000

mRNA expression patterns in different stages of asbestos-induced carcinogenesis in rats.

Human malignant mesotheliomas are induced almost exclusively by fibrous dusts. The nature of interactions between fibers and target cells, and the molecular mechanisms leading to tumorigenesis, are not yet understood. Here, the mRNA expression patterns at different stages of asbestos-induced carcinogenesis in rats were monitored by suppression subtractive hybridization (SSH) and array assay. Several genes were upregulated in pretumorous tissues from asbestos-treated rats, in asbestos-induced tumors and in cells treated with asbestos in vitro. The upregulation of the proto-oncogene c-myc, fra-1 and egfr in fiber-induced carcinogenesis was demonstrated at different stages of carcinogenesis. A possible role of Fra-1 as one of the dimeric proteins generating the AP-1 transcription factor was substantiated by its dose-dependent expression in mesothelial cells treated with asbestos in vitro. The upregulation of osteopontin (an extracellular matrix protein) and of zyxin and integrin-linked kinase (intracellular proteins associated with the focal adhesion contact), indicate that fibers may affect integrin-linked signal transduction and extracellular matrix proteins.

Animals↗
PubMed1999

Prolonged elevation of plasma free fatty acids desensitizes the insulin secretory response to glucose in vivo in rats.

Prolonged exposure of pancreatic islets to free fatty acids (FFAs) inhibits glucose-stimulated insulin secretion (GSIS) in vitro. However, FFA inhibition of GSIS has not been clearly demonstrated in vivo. We examined the in vivo effect of prolonged elevation of plasma FFAs on GSIS using a two-step hyperglycemic clamp in rats treated with a 48-h intravenous infusion of either 20% Intralipid plus heparin (INT) (5 microl/min plus heparin, 0.1 U/min; n = 8), oleate (OLE) (1.3 microEq/min; n = 6), saline (SAL) (n = 6), or bovine serum albumin (BSA) (vehicle for OLE; n = 5). Because there was no difference in any of the parameters between BSA and SAL rats, these groups were combined as control rats (CONT) (n = 11). At the end of the 48-h OLE/INT/CONT infusions, after an overnight fast, plasma glucose was clamped for 2 h at 13 mmol/l and for another 2 h at 22 mmol/l. Preclamp plasma FFAs were elevated twofold (P < 0.01) versus CONT with both INT and OLE (NS, INT vs. OLE). Preclamp glucose, insulin, and C-peptide levels were higher in INT than in CONT rats (P < 0.05), suggesting insulin resistance, but they were not different in OLE and CONT rats. The insulin and C-peptide responses to the rise in plasma glucose from basal to 13 mmol/l were lower in OLE (336 +/- 72 pmol/l and 1.2 +/- 0.1 nmol/l, P < 0.01 and P < 0.05, respectively) than in CONT (552 +/- 54 and 1.9 +/- 0.1) rats, but they were not different between CONT and INT rats (648 +/- 150 and 2.0 +/- 0.4). The insulin and C-peptide responses to the rise in plasma glucose from 13 to 22 mmol/l were lower in both INT (1,188 +/- 204 pmol/l and 3.0 +/- 0.3 nmol/l, P < 0.01 and P < 0.001) and OLE (432 +/- 60 and 1.7 +/- 0.2, P < 0.001 vs. CONT or INT) rats than in CONT rats (1,662 +/- 174 and 5.0 +/- 0.6). In summary, 1) both INT and OLE decreased GSIS in vivo in rats, and 2) the impairing effect of INT on GSIS was less than that of OLE, which might be due to the different type of fatty acid (mostly polyunsaturated in INT versus monounsaturated as OLE) and/or to differential effects of INT and OLE on insulin sensitivity. In conclusion, prolonged elevation of plasma FFAs can desensitize the insulin secretory response to glucose in vivo, thus inducing a beta-cell defect that is similar to that found in type 2 diabetes.

Animals↗
PubMed1999

Free fatty acids impair hepatic insulin extraction in vivo.

Hyperinsulinemia is a common finding in obesity and results from insulin hypersecretion and impaired hepatic insulin extraction. In vitro studies have shown that free fatty acids (FFAs), which are often elevated in obesity, can impair insulin binding and degradation in isolated rat hepatocytes. To investigate whether FFAs impair hepatic insulin extraction (E(H)) in vivo, either saline (SAL) or 10% Intralipid (0.03 ml x kg(-1) x min(-1)) plus heparin (0.44 U x kg(-1) x min(-1)) (IH) was infused into normal dogs to elevate FFA levels. Insulin was infused intraportally at 18 pmol x kg(-1) x min(-1) for 150 min (period A, high insulin dose), and then at 2.4 pmol x kg(-1) x min(-1) for another 150 min (period B, low insulin dose). After the low portal insulin dose, additional insulin was infused peripherally at 8.4 pmol x kg(-1) x min(-1) for 120 min (period C) to assess the clearance of insulin from the peripheral plasma. In 16 paired experiments, FFA levels were 1,085 +/- 167, 1,491 +/- 240, 1,159 +/- 221 micromol/l (IH) and 221 +/- 44, 329 +/- 72, 176 +/- 44 micromol/l (SAL) in periods A, B, and C, respectively. Peripheral insulin levels were greater with IH (P < 0.001) than with SAL in all periods (1,620 +/- 114, 126 +/- 12, 1,050 +/- 72 pmol/l for IH vs. 1,344 +/- 168, 96 +/- 4.2, 882 +/- 60 pmol/l for SAL). Glucose clearance was impaired by IH in all periods (P < 0.05), whereas glucose production was slightly increased by IH during period B. Peripheral insulin clearance (Cl) and E(H) were calculated from the insulin infusion rate and insulin concentration data in each period by taking into account the nonlinearity of insulin kinetics. Cl was lower (P < 0.01) with IH (9.6 +/- 0.6, 12.0 +/- 0.9, 10.2 +/- 0.6 ml x kg(-1) x min(-1)) than with SAL (11.2 +/- 1, 13.6 +/- 0.7, 11.9 +/- 0.9 ml x kg(-1) x min(-1)) in periods A, B, and C. E(H) was also lower (P < 0.05) with IH (25 +/- 4, 40 +/- 5, 32 +/- 5%) than with SAL (30 +/- 2.8, 47 +/- 3, 38 +/- 3%). We conclude that FFAs can impair hepatic insulin extraction in vivo at high and low insulin levels, an effect that may contribute to the peripheral hyperinsulinemia of obesity.

Animals↗
PubMed1999

Glucagon-like peptide 1 increases insulin sensitivity in depancreatized dogs.

To determine whether glucagon-like peptide (GLP)-1 increases insulin sensitivity in addition to stimulating insulin secretion, we studied totally depancreatized dogs to eliminate GLP-1's incretin effect. Somatostatin was infused (0.8 microg x kg(-1) x min(-1)) to inhibit extrapancreatic glucagon in dogs, and basal glucagon was restored by intraportal infusion (0.65 ng x kg(-1) x min(-1)). To simulate the residual intraportal insulin secretion in type 2 diabetes, basal intraportal insulin infusion was given to obtain plasma glucose concentrations of approximately 10 mmol/l. Glucose was clamped at this level for the remainder of the experiment, which included peripheral insulin infusion (high dose, 5.4 pmol x kg(-1) x min(-1), or low dose, 0.75 pmol x kg(-1) x min(-1)) with or without GLP-1(7-36) amide (1.5 pmol x kg(-1) x min(-1)). Glucose production and utilization were measured with 3-[3H]glucose, using radiolabeled glucose infusates. In 12 paired experiments with six dogs at the high insulin dose, GLP-1 infusion resulted in higher glucose requirements than saline (60.9+/-11.0 vs. 43.6+/-8.3 micromol x kg(-1) x min(-1), P< 0.001), because of greater glucose utilization (72.6+/-11.0 vs. 56.8+/-9.7 micromol x kg(-1) x min(-1), P<0.001), whereas the suppression of glucose production was not affected by GLP-1. Free fatty acids (FFAs) were significantly lower with GLP-1 than saline (375.3+/-103.0 vs. 524.4+/-101.1 micromol/l, P<0.01), as was glycerol (77.9+/-17.5 vs. 125.6+/-51.8 micromol/l, P<0.05). GLP-1 receptor gene expression was found using reverse transcriptase-polymerase chain reaction of poly(A)-selected RNA in muscle and adipose tissue, but not in liver. Low levels of GLP-1 receptor gene expression were also found in adipose tissue using Northern blotting. In 10 paired experiments with five dogs at the low insulin dose, GLP-1 infusion did not affect glucose utilization or FFA and glycerol suppression when compared with saline, suggesting that GLP-1's effect on insulin action was dependent on the insulin dose. In conclusion, in depancreatized dogs, GLP-1 potentiates insulin-stimulated glucose utilization, an effect that might be contributed in part by GLP-1 potentiation of insulin's antilipolytic action.

Adipose Tissue↗
PubMed1999

Chronic renal failure causing brown tumors and myelopathy. Case report and review of pathophysiology and treatment.

Brown tumors (osteoclastomas) are histologically benign lesions that are caused by primary or secondary hyperparathyroidism. Secondary hyperparathyroidism is a frequent complication of chronic renal failure. Skeletal brown tumors are relatively uncommon, and brown tumors that involve the spine are considered very rare. The authors present the case of a 37-year-old woman with systemic lupus erythematosus and hemodialysis-dependent anuric renal failure, in whom spinal cord compression developed due to a brown tumor and pathological fracture at T-9. The patient underwent transthoracic decompressive surgery and spinal reconstruction in which cadaveric femoral allograft and instrumentation were used. Brown tumors of the vertebral column require surgical treatment if medical therapy and parathyroidectomy fail to halt their progression or if acute neurological deterioration occurs. In patients with renal failure bone healing is delayed and there is an increased risk that healing will fail because the metabolic derangements can result in severe osteoporosis. Surgical reconstruction of the spine may require the use of augmentation with instrumentation and aggressive treatment of hyperparathyroidism to achieve successful outcomes.

Adult↗
PubMed1997

Biochemical changes induced by malarial parasites.

The morbidity associated with malaria plays a key role in the staggering of the social and economic development of human race. The investigations on the cellular, biochemical and molecular organisation of the malarial parasite are important to understand the host parasite interactions in a better way. The parasite induces several biochemical and biophysical alterations in the host red cells. It is well recognized that cation homeostasis is vital to basic aspects of cell functions. Though the pathogenesis of anaemia associated with Plasmodium falciparum infection is multifactorial, the complex mechanisms involving the role of oxidant stress and calcium imbalance of infected red cells plays an important role.

Animals↗
PubMed1995

Male germ cell extracts contain proteins binding to the conserved 3'-end of mouse p68 RNA helicase mRNA.

The 3'-untranslated regions of human and mouse p68 RNA helicase mRNA are highly conserved, suggesting a functional role of the nucleic acid sequence itself in regulation of p68 RNA helicase expression. Secondary structure evaluations revealed no indications for a predominant folding pattern within the 3'-UTR. To test the potential of the 3'-sequence to serve as a target for specific binding proteins, gel shift assays were performed. In vitro-synthesized RNA was incubated with cytoplasmic as well as nuclear extracts from mouse male germ cells. Evidence was obtained that such specific proteins exist in germ cell extracts. Photo-crosslinking experiments suggested that a 30 kDa protein was involved in these binding events.

Animals↗
PubMed1995

Psychosocial aspect of planned induction of labour.

One hundred patients of planned induction and 25 cases of spontaneous delivery were interviewed on the various aspects of labour care in the postpartum period. Majority were satisfied with overall care and 65% were of the opinion of opting for induction next time.

Adult↗
PubMed1993

Femur fractures caused by gunshots: treatment by immediate reamed intramedullary nailing.

Fractures of the femur caused by gunshots are increasingly common. There is no standard treatment of these fractures since there are no clear guidelines relating these injuries to open fracture classification. We reviewed our experience with such fractures, which included 65 patients who had an immediate reamed intramedullary nail placed as treatment. The soft-tissue injury, vascular injury, missile velocity, and length of hospital stay were evaluated. We found that all patients healed with no infections. The overall morbidity and average hospital stay were decreased compared with studies advocating delayed intramedullary nailing and prolonged intravenous antibiotics. We recommend that patients with fractures of the femur caused by gunshots are candidates for immediate reamed intramedullary nailing providing that there is only mild to moderate soft-tissue contamination and no evidence of major devitalization.

Adolescent↗
PubMedDate not supplied

Epidural hematoma following epidural analgesia in a patient receiving unfractionated heparin for thromboprophylaxis.

BACKGROUND AND OBJECTIVES: The practice of providing postoperative epidural analgesia for patients receiving deep venous thromboprophylaxis with unfractionated heparin is common. This case report is intended to heighten awareness of comorbid risk factors for epidural hematoma and to bring attention to the new ASRA consensus guidelines on the management of neuraxial anesthesia in the presence of standard heparin. CASE REPORT: A 79-year-old woman with apparently normal coagulation and receiving no antiplatelet agents required an abdominoperineal resection for recurrent squamous cell carcinoma of the anus. Approximately 2 hours after her preoperative dose of 5,000 U unfractionated heparin, an epidural catheter was placed on the third attempt. Subcutaneous heparin was subsequently administered every 12 hours. Her international normalized ratio became slightly elevated during surgery while the partial thromboplastin time and platelet count remained normal. The catheter was removed on postoperative day 3, 6 hours after the last dose of heparin. The patient developed signs of an epidural hematoma requiring surgical evacuation on postoperative day 4. The presence of previously undiagnosed spinal stenosis may have contributed to her symptoms. CONCLUSION: Management of postoperative epidural analgesia in the patient receiving thromboprophylaxis with unfractionated heparin requires appropriate timing of epidural insertion and removal, monitoring of coagulation status and vigilance.

Aged↗