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Biomedical subjects

A Mehra

Publications and source records attributed to A Mehra.

At least 19 recordsLinked to original sources
PubMed2006

Bacteriology swab in primary total hip arthroplasty-- does it have a role?

Infection in joint replacement is a devastating complication, and in spite of the advances in surgery, it remains a challenge. The rate of deep infection following primary hip/knee arthroplasty is between 1% and 2%. The aim of this study was to determine whether obtaining bacteriology swabs at the time of surgery could help in further reducing the rate of infection following joint arthroplasty. A bacteriology swab of the synovial fluid was taken after opening the capsule of the hip joint and was sent for culture and sensitivity. Out of 142 swabs sent, four (2.1%) were found to be positive. Three of these patients were treated with antibiotics after obtaining sensitivities. None of the patients developed deep infection. Bacteriology swab in primary joint arthroplasty may have a role and may help in further reducing the incidence of deep infection in joint replacement surgery.

Antibiotic Prophylaxis↗
PubMed2004

C reactive protein and skin temperature post total knee replacement.

We prospectively assessed 20 patients following uncomplicated total knee replacement (TKR). Clinical status, skin temperature and C-reactive protein (CRP) were measured preoperatively and at intervals up to 18 weeks. The CRP rose postoperatively up to 5-7 days but returned to normal values by 6 weeks. The skin temperature remained elevated up to 18 weeks. We concluded that in uncomplicated cases, the CRP should be within normal limits by 6 weeks after operation, but skin temperature may remain elevated up to 18 weeks. A sustained rise in these values may indicate the development of a complication such as infection and the patient must be closely monitored.

Adult↗
PubMed2004

Anti-adhesion molecule strategies as potential neuroprotective agents in cerebral ischemia: a critical review of the literature.

Despite recent advances in the understanding of the pathophysiology of cerebral ischemia, current approaches attempting to prevent ischemic brain damage after an acute stroke remain quite inadequate. Today, ischemic stroke remains the third leading cause of death in industrialized nations, and the leading cause of disability requiring long term institutional care in the U.S and other industrialized nations. While one treatment, tissue plasminogen activator, has shown efficacy in clinical trials, safety concerns limit its role in clinical practice to a narrow time window of use. Acute cerebral ischemia has been shown to evoke a profound and deleterious upregulation of the inflammatory response, initiated within the cerebral microvasculature. Recently, research efforts have focused on targeting individual components of the inflammatory cascade, such as leukocyte activation and adhesion, in an attempt to develop potential neuroprotective agents. While these strategies have shown promise preclinically, clinical trials have yet to show clear benefit. Here, we review the current understanding of the pathophysiologic consequences of acute cerebral ischemic injury. Additionally, we discuss the role of the inflammatory cascade, with specific attention given to the deleterious role played by leukocyte activation and adhesion in stroke. Finally, relevant efforts to translate these basic science observations into clinical efficacy in acute stroke trials are critically reviewed.

Animals↗
PubMed2004

Contamination of surface soils, river water and sediments by trace metals from copper processing industry in the Churnet River Valley, Staffordshire, UK.

The impacts of a functional and a demolished copper processing works on the aquatic and terrestrial environment in the vicinity of the works was investigated by determining the levels of selected trace metals in river water, river sediments, channel margin sediments and overbank soils. Samples were taken at five sites within an area of the Churnet Valley in Staffordshire, where the River Churnet flows through the two works. Analysis of river water samples by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) has shown that only copper is present above background levels considered to typify uncontaminated rivers. Analysis of river sediments, channel margin sediments and overbank soils by nitric-perchloric acid digestion and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) analysis has indicated contamination by arsenic, cadmium and copper in the vicinity of both works. Arsenic and copper are deposited primarily within the aquatic environment, although some contamination of the terrestrial environment by copper is also observed. Cadmium is deposited primarily within the terrestrial environment. The deposition of arsenic and copper in river and channel margin sediments respectively is also related to current and historical contamination.

Arsenic↗
PubMed2004

A safe, simple and cost-effective protocol for blood transfusion in primary total knee replacement.

BACKGROUND: Patients undergoing total knee replacement (TKR) in the UK usually have either blood cross-matched or have an auto-transfusion of drained blood postoperatively. A previous retrospective audit of blood requirements in patients who had undergone primary TKR showed that a large amount of cross-matched blood was wasted as the CT ratio (ratio of number of units of blood cross-matched to number of units transfused) of 4.9:1 was obtained. The range recommended by the Blood Transfusion Society is 2:1 to 3:1. METHODS: A protocol was introduced to group and save plus antibody screen for all patients and to cross-match 2 units of blood pre-operatively in patients with either a haemoglobin of less than 12.5 g/dl or with multiple red cell antibodies in their blood. The trigger point for blood transfusion postoperatively was also reduced from 9.0 g/dl to 8.0 g/dl, unless the patient was clinically symptomatic. RESULTS: A further prospective study involving 50 patients was carried out using the new protocol. Five patients required cross-matching pre-operatively, three with haemoglobin less than 12.5 g/dl and two with multiple red cell antibodies. Postoperatively, the patients with haemoglobin of less than 12.5 g/dl required blood transfusion of 2 units each, reducing the CT ratio to 1.7:1. The patients with red cell antibodies did not require a blood transfusion. CONCLUSIONS: The benefits from above protocol are 2-fold: patient safety, as risks of transfusion are avoided; and cost saving, in regards to haematology technician time and auto-transfusion sets which cost around pound 70 each.

Aged↗
PubMed2003

The use of a mobile lithotripter in the treatment of tennis elbow and plantar fasciitis.

OBJECTIVE: To evaluate the use of the mobile lithotripter in the treatment of tennis elbow and plantar fasciitis. METHOD: A prospective single blind randomised trial was performed on 24 patients with tennis elbow and 23 patients with plantar fasciitis, with a mean duration of symptoms of 11 months. All patients had failed one or more method of treatment--conservative, topical non-steriodal anti-inflammatory drugs (NSAID), steroid injection and/or surgery. The patients were divided into treatment and placebo groups. The placebo group received treatment with a clasp on the elbow/heel to stop penetration of shock waves. A baseline pain score was obtained using the Million Visual Analogue scale (0-10). The affected area was infiltrated with 3-5mls of 1% lignocaine. The treatment consisted of 2000 shock waves at 2.5 bars of air pressure with a frequency of 8-10Hz. A total of three treatments were given at an interval of two weeks, each lasting for three to four minutes. RESULTS: In the treatment groups, a final pain score at six months post treatment showed significant improvement (three or more points) in 78% of patients with tennis elbow and 93% of patients with plantar fasciitis. In the placebo groups, significant improvement was seen in one patient (9%) with tennis elbow. The other patients in the placebo groups did not show significant improvement. This was statistically significant (chi square test) for both conditions. CONCLUSION: The mobile lithotripter is an effective way of treating tennis elbow and plantar fasciitis but warrants further larger studies.

Fasciitis, Plantar↗
PubMed2003

Mechanisms of copper tolerance by Armeria maritima in Dolfrwyong Bog, north Wales--initial studies.

Preliminary field studies were carried out at Dolfrwynog Bog in July 2000. Replicate samples of water, Armeria maritima plants and the soils adhering to its roots were collected and analysed for copper. Concentrations of up to 6486 mg kg-1 of copper in the soils were recorded. Accumulation of copper by the plant as expressed by concentration factors (CF) show that it is acting mainly as a copper excluder. Of the copper that is taken up, most of it is retained within the roots with very little being transported to the shoots of the plant. Moreover, a further possible mechanism of tolerance is exhibited by the excretion of copper through its decaying leaves. Towards the use of in vitro cultures to study the copper tolerance mechanisms in A. maritima a micropropagation protocol has been developed. The ex vitro plants have been rooted and established in compost.

Adaptation, Physiological↗
PubMed2000

Idiopathic familial onychomadesis.

Onychomadesis is defined as spontaneous separation of the nail plate from the nail bed, beginning at its proximal end and resulting in the shedding of the nail. It has been associated with a variety of clinical settings, including systemic illnesses, generalized skin diseases, and drug therapies. There have been a small number of reports in the older literature of idiopathic onychomadesis occurring in a familial pattern. We report the case of a healthy 12-year-old girl and her mother, both of whom have experienced recurrent onychomadesis affecting multiple digits, and in the absence of any causal disease or medication.

Adult↗
PubMed1999

Negative regulation of male development in Caenorhabditis elegans by a protein-protein interaction between TRA-2A and FEM-3.

The tra-2 gene of the nematode Caenorhabditis elegans encodes a predicted membrane protein, TRA-2A, that promotes XX hermaphrodite development. Genetic analysis suggests that tra-2 is a negative regulator of three genes that are required for male development: fem-1, fem-2, and fem-3. We report that the carboxy-terminal region of TRA-2A interacts specifically with FEM-3 in the yeast two-hybrid system and in vitro. Consistent with the idea that FEM-3 is a target of negative regulation, we find that excess FEM-3 can overcome the feminizing effect of tra-2 and cause widespread masculinization of XX somatic tissues. In turn, we show that the masculinizing effects of excess FEM-3 can be suppressed by overproduction of the carboxy-terminal domain of TRA-2A. A FEM-3 fragment that retains TRA-2A-binding activity can masculinize fem-3(+) animals, but not fem-3 mutants, suggesting that it is possible to release and to activate endogenous FEM-3 by titrating TRA-2A. We propose that TRA-2A prevents male development by interacting directly with FEM-3 and that a balance between the opposing activities of TRA-2A and FEM-3 determines sex-specific cell fates in somatic tissues. When the balance favors FEM-3, it acts through or with the other FEM proteins to promote male cell fates.

Animals↗
PubMed1999

Mouse NKR-P1B, a novel NK1.1 antigen with inhibitory function.

The mouse NK1.1 Ag originally defined as NK cell receptor (NKR)-P1C (CD161) mediates NK cell activation. Here, we show that another member of the mouse CD161 family, NKR-P1B, represents a novel NK1.1 Ag. In contrast to NKR-P1C, which functions as an activating receptor, NKR-P1B inhibits NK cell activation. Association of NKR-P1B with Src homology 2-containing protein tyrosine phosphatase-1 provides a molecular mechanism for this inhibition. The existence of these two NK1.1 Ags with opposite functions suggests a potential role for NKR-P1 molecules, such as those of the Ly-49 gene family, in regulating NK cell function.

Amino Acid Sequence↗
PubMed1998

Comparison of intracoronary Doppler guide wire and transesophageal echocardiography in measurement of flow velocity and coronary flow reserve in the left anterior descending coronary artery.

BACKGROUND: The intracoronary Doppler tipped guide wire has been shown to be highly accurate in the measurement of coronary flow velocity (CFV). Recent studies have indicated that blood flow velocity in the left anterior descending coronary artery (LAD) can be determined by transesophageal echocardiography (TEE). The purpose of this study was to compare flow velocity recordings and coronary flow reserve measurements in the LAD by TEE with those obtained by Doppler guide wire. METHODS AND RESULTS: The study population consisted of 14 patients with chest pain and normal coronary arteriograms. After routine coronary arteriography was performed, a 0.014-inch Doppler guide wire was advanced into the proximal part of the LAD. After baseline measurement of coronary flow velocity (CFV) was obtained, 140 microg/kg/min adenosine was administered intravenously for 3 minutes, and the flow velocity was recorded. TEE was performed within 24 hours of the cardiac catheterization. After baseline measurements of CFV in the LAD, heart rate, and blood pressure were obtained, 140 microg/kg/min adenosine was administered intravenously, and the CFV was recorded. Coronary flow reserve was calculated as the ratio of the peak diastolic CFV during adenosine infusion to the peak diastolic CFV at baseline. A good correlation was found (r = 0.91, p < 0.0001) between CFV by Doppler guide wire and that determined by TEE. A good correlation was also found between the coronary flow reserve assessed by Doppler guide wire and that determined by TEE (r = 0.92, p < 0.0001). CONCLUSION: Our data indicate that CFV and coronary flow reserve in the LAD can be accurately measured by transesophageal echocardiography.

Adult↗
PubMed1998

Renal circulatory effects of adenosine in patients with chronic heart failure.

OBJECTIVES: We sought to study the renal circulatory effects of adenosine in patients with chronic congestive heart failure (CHF). BACKGROUND: Renal blood flow (RBF) is often reduced in patients with chronic CHF and may lead to decreased renal function. The cause of reduced RBF is multifactorial and involves systemic as well as local vasoregulatory mechanisms. Stimulation of renal adenosine A1 receptors in animal models has resulted in a significant vasoconstriction of afferent and efferent glomerular arterioles and deterioration of renal function. Although adenosine serum levels have been shown to be elevated in patients with CHF, their effect on the renal circulation in this patient population has not been studied. METHODS: Nine patients with CHF from left ventricular systolic dysfunction were studied. The effects of adenosine at a dose of 10(-5) mol/liter infused directly into the main renal artery on heart rate, renal artery blood pressure, renal artery cross-sectional area (measured by intravascular ultrasound), renal Doppler blood flow velocity (measured by a Doppler flow wire in the renal artery), RBF and renal vascular resistance (RVR) were evaluated. RESULTS: Infusion of adenosine resulted in no significant effect on heart rate or renal artery blood pressure but caused a substantial increase in RVR (11,204 +/- 1,469 to 31,494 +/- 3,911 dynes x s x cm(-5), p = 0.0005), which led to a marked fall in RBF in every patient (mean values 376 +/- 36 to 146 +/- 22 ml/m2, p = 0.0002). These changes in RVR and RBF were associated with no significant change in renal artery cross-sectional area (0.389 +/- 0.040 to 0.375 +/- 0.033 cm2, p = 0.3). CONCLUSIONS: Stimulation of renal adenosine receptors in patients with CHF results in marked renal vasoconstriction that leads to an important reduction in RBF. Lack of change in renal artery cross-sectional area suggests that adenosine affects intrarenal resistance blood vessels rather than large conductance vessels. These results may indicate a rationale for investigation of renal adenosine receptor blockade for enhancement of RBF and improvement of renal function in patients with chronic CHF.

Adenosine↗
PubMed1998

Medea is a Drosophila Smad4 homolog that is differentially required to potentiate DPP responses.

Mothers against dpp (Mad) mediates Decapentaplegic (DPP) signaling throughout Drosophila development. Here we demonstrate that Medea encodes a MAD-related protein that functions in DPP signaling. MEDEA is most similar to mammalian Smad4 and forms heteromeric complexes with MAD. Like dpp, Medea is essential for embryonic dorsal/ventral patterning. However, Mad is essential in the germline for oogenesis whereas Medea is dispensable. In the wing primordium, loss of Medea most severely affects regions receiving low DPP signal. MEDEA is localized in the cytoplasm, is not regulated by phosphorylation, and requires physical association with MAD for nuclear translocation. Furthermore, inactivating MEDEA mutations prevent nuclear translocation either by preventing interaction with MAD or by trapping MAD/MEDEA complexes in the cytosol. Thus MAD-mediated nuclear translocation is essential for MEDEA function. Together these data show that, while MAD is essential for mediating all DPP signals, heteromeric MAD/MEDEA complexes function to modify or enhance DPP responses. We propose that this provides a general model for Smad4/MEDEA function in signaling by the TGF-beta family.

Amino Acid Sequence↗
PubMed1997

Prediction of Solubility of Nonpolar Gases in Micellar Solutions of Ionic Surfactants

The solubilities of methane, carbon dioxide, ethane, and propane have been determined experimentally at 1 atm partial pressure and 25&deg;C in aqueous solutions of sodium dodecyl sulfate and cetyltrimethylammonium bromide. For this purpose a specially developed apparatus is used, which is relatively simple compared to those reported in the literature hitherto. Above the CMC, the solubility of each gas increases linearly with surfactant concentration indicating micellar solubilization. The degree of solubilization is greatest for propane and decreases in the order propane > ethane > carbon dioxide > methane. Both the length of the alkyl chain and the properties of the head-group region (i.e., the micelle-water interfacial tension) are observed to determine the intramicellar solubility. A method for estimating the solubilities is also proposed based on the rationale that the micellar phase may be represented by a droplet of a "model solvent" into which the solubilizate molecule dissolves as it would in a bulk solvent. The mixture of the solute species and the model solvent is assumed to behave as a regular solution. Accordingly, a characteristic solubility parameter is estimated for the model solvent from the interaction potential between two adjacent surfactant molecules in a micelle. The solubility computed using the regular solution approximation is further corrected for the Laplace pressure that acts across the curved micelle-water interface and generally reduces the intramicellar solubility. It is concluded that for small nonpolar solutes, micellar solubilities may be reasonably well predicted by assuming that the model solvent has a solubilizing capacity (i.e., solubility parameter) close to that of a bulk equivalent alkane. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗