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Biomedical subjects

W Khan

Publications and source records attributed to W Khan.

At least 19 recordsLinked to original sources
PubMed2006

Jasmonates induce Nod factor production by Bradyrhizobium japonicum.

Jasmonates are signaling molecules involved in induced systemic resistance, wounding and stress responses of plants. We have previously demonstrated that jasmonates can induce nod genes of Bradyrhizobium japonicum when measured by beta-galactosidase activity. In order to test whether jasmonates can effectively induce the production and secretion of Nod factors (lipo-chitooligosaccharides, LCOs) from B. japonicum, we induced two B. japonicum strains, 532C and USDA3, with jasmonic acid (JA), methyl jasmonate (MeJA) and genistein (Ge). As genistein is well characterized as an inducer of nod genes it was used a positive control. The high-performance liquid chromatography (HPLC) profile of LCOs isolated following treatment with jasmonates or genistein showed that both JA and MeJA effectively induced nod genes and caused production of LCOs from bacterial cultures. JA and MeJA are more efficacious inducers of LCO production than genistein. Genistein plus JA or MeJA resulted in greater LCO production than either alone. A soybean root hair deformation assay showed that jasmonate induced LCOs were as effective as those induced by genistein. This is the first report that jasmonates induce Nod factor production by B. japonicum. This report establishes the role of jasmonates as a new class of signaling molecules in the Bradyrhizobium-soybean symbiosis.

Bradyrhizobium↗
PubMed2006

The S-Quattro in the management of sports injuries of the fingers.

Intra-articular phalangeal fractures of the small joints of the hand are difficult sports injuries to manage. The Stockport Serpentine Spring System, abbreviated to S-Quattro was developed by the senior author as an external fixator to treat these fractures. We present the largest series of patients with sports injuries treated with the S-Quattro. Twenty patients with these fractures were treated over a three-year period. The injured joint was distracted after inserting two pins percutaneously into normal phalangeal bone. Two serpentine springs were then inserted between the pins applying distraction to the fracture site. The fixation devices were removed in clinic between 4 and 6 weeks. Objective analysis revealed an average arc of movement of the affected joint of 94 degrees at an average follow-up of 14 months. The mean DASH score was 5 indicating mild impairment. All of the patients were satisfied with the results and the radiographic appearances were satisfactory. The S-Quattro is a versatile system that permits some movement of the injured joint while maintaining reduction. It is relatively free of complications with good results. We advocate the routine use of the S-Quattro in view of its inherent simplicity and the good results it produces with these difficult sports injuries.

Adolescent↗
PubMed2005

The S-Quattro in the management of acute intraarticular phalangeal fractures of the hand.

Intraarticular phalangeal fractures of the hand are difficult and challenging to manage. Dynamic external fixation devices offer the advantages of allowing distraction of the impacted fracture and early joint mobilization. We present our study of 100 patients with a variety of fractures who were treated with the S-Quattro technique over a 6-year period, with an average follow-up of 10.5 months. The mean active range of motion regained was 92 degrees for proximal interphalangeal joints (81 fractures), 82 degrees for distal interphalangeal joints (10 fractures), 91 degrees for metacarpophalangeal joints (6 fractures) and 80 degrees for interphalangeal joints of the thumb (3 fractures). Only nine patients complained of mild or moderate pain. Postoperative radiographic appearances were satisfactory in all but five out of the 100 patients. This device is a simple and effective technique for the management of these difficult fractures. It offers advantages in terms of versatility, ease of application, good tolerance by patients, few complications and good outcome.

Adolescent↗
PubMed2004

Management of intra-articular fractures of the proximal interphalangeal joint by internal fixation and bone grafting.

INTRODUCTION: Intra-articular fractures of the proximal interphalangeal joint are usually treated by one of many methods of external fixation, but this does not restore the articular surface. We describe a procedure where bone grafting and internal fixation are used to restore the articular surface. PATIENTS AND METHODS: A prospective study was conducted in which three patients underwent surgical treatment for this fracture. We describe a surgical procedure where bone graft harvested from the distal radius is packed through a diaphyseal window to restore the articular surface. This is followed by internal fixation with mini-screws. RESULTS: The average follow-up was 61 months. At last follow-up the average arc of movement of the proximal interphalangeal joint was 100 deg and the average Disability of the Arm, Shoulder and Hand (DASH) Score was 2. Postoperative radiographs showed restoration of the articular contour in all three patients. CONCLUSION: The surgical technique described addresses the issues of restoration of the articular surface and permits early mobilisation. The results for our group are excellent and compare favourably with those achieved using external fixators described in the literature.

Adult↗
PubMed2004

Repair of distal biceps tendon rupture with the Biotenodesis screw.

BACKGROUND: Distal biceps tendon ruptures are uncommon injuries with only around 300 cases reported in the literature. Current management tends to favour anatomical reinsertion of the tendon into the radial tuberosity, especially in young and active individuals. These injuries are commonly repaired using either a single anterior incision with suture anchors or the Boyd-Anderson dual incision technique. CASE REPORT: We report the use of a bioabsorbable interference screw for the repair of distal biceps tendon rupture using a minimal incision technique. In this technique the avulsed tendon and a bioabsorbable screw are secured in a drill hole on the radial tuberosity using whip stitch and fibre wire sutures according to Biotenodesis system guidelines. CONCLUSION: The technique described requires minimal volar dissection that is associated with a reduced number of synostosis and posterior interosseous nerve injuries. The bioabsorbable interference screw has all the advantages of being biodegradable and has been shown to have greater pullout strength than suture anchors. It is also a reasonable alternative to titanium screws in terms of primary fixation strength. The strong fixation provided allows early active motion and return to previous activities as seen in our case.

Arm Injuries↗
PubMed2001

Use of membrane collectors in electrostatic precipitators.

Membrane collection surfaces, developed and patented by researchers at Ohio University, were used to replace steel plates in a dry electrostatic precipitator (ESP). Such replacement facilitates tension-based rapping, which shears the adhered particle layer from the collector surface more effectively than hammer-based rapping. Tests were performed to measure the collection efficiency of the membranes and to quantify the potential improvements of this novel cleaning technique with respect to re-entrainment. Results indicate that even semiconductor materials (e.g., carbon fibers) collect ash nearly as efficiently as steel plates, potentially indicating that collection surface resistivity is primarily dictated by the accumulated ash layer and not by the underlying plate conductivity. In addition, virtually all sheared particles separated from the collecting membranes fell within the boundary layer of the membrane, indicating extremely low potential for re-entrainment.

Air Pollution↗
PubMed2001

Association of pulmonary artery catheter use with in-hospital mortality.

OBJECTIVE: To determine the association of pulmonary artery catheter (PAC) use with in-hospital mortality. DESIGN: Prospective, observational study. SETTING: The medical intensive care units (MICU) of two teaching hospitals. METHODS: The study included 751 adults who were admitted to the MICU, excluding those who stayed for <24 hrs. Demographics and the worst Acute Physiology and Chronic Health Evaluation (APACHE) II score within the first 24 hrs of MICU admission were obtained. Daily logistic organ dysfunction system (LODS) scores were calculated. The associations of in-hospital mortality with the admission source, admission disease category, APACHE II scores, the worst LODS scores, mechanical ventilation, and PAC use were determined using chi-square, Mann-Whitney U, and multiple logistic regression analysis tests. p Values < 0.05 were considered significant. RESULTS: Mean patient age was 52.6 +/- 17.1 yrs; 425 (57%) were male; 464 (62%) were African-American, 275 (37%) Caucasian, 6 (1%) Asian, and 6 (1%) Hispanic. PAC was used in 119/751 (16%). The median APACHE II and worst LODS scores were 19 and 4, respectively. The in-hospital mortality rate was 159/751 (21%). The median APACHE II score for survivors was 17.5, compared with 28.0 for nonsurvivors (p <.0001). The worst median LODS score was 4 for survivors, compared with 11 for nonsurvivors (p <.0001). Sixty-four (54%) of the 119 patients with PAC died, compared with 95 (15%) of the 632 without PAC (p <.0001). Multiple logistic regression analysis showed that higher APACHE II-predicted mortality rate (p =.0088) and worst daily LODS score (p <.0001) were associated with increased mortality. The admission source, admission disease category, PAC use, and mechanical ventilation were not associated with in-hospital mortality. CONCLUSIONS: This study could not detect an association between PAC use and mortality. The APACHE II-predicted mortality rate and the development of multiple organ dysfunction were the main determinants of poor outcome in critically ill patients admitted to MICU.

APACHE↗
PubMed2001

Troponin T: role in altering patient management and enabling earlier discharge from a district general hospital.

The use of troponin T to facilitate early patient discharge was investigated in a prospective study in a district general hospital. Troponin T was measured in 91 patients admitted over a period of 6 months with chest pain but without evidence of myocardial infarction. The main outcome measure was length of hospital stay. A negative troponin T was found in 70 patients. Fifty of these were discharged within 24 h of the troponin result being available and they had a significantly shorter hospital stay than a case control group and a historical control group from the previous 6 months. Troponin T measurement has a role in altering patient management by enabling early discharge, resulting in significant cost savings and increasing bed availability.

Adult↗
PubMed2001

Treatment of Felty's syndrome with leflunomide.

Felty's syndrome (FS) is a rare manifestation of severe rheumatoid arthritis (RA). It is an immune mediated inflammatory process, usually treated with standard disease modifying antirheumatic drugs. We describe a case of severe FS that developed in a patient receiving methotrexate therapy for RA. Treatment with etanercept resulted in severe allergic cutaneous reactions. The patient subsequently responded to treatment with leflunomide. The response included dramatic improvement of leukopenia and neutropenia as well as excellent control of his arthritis. Leflunomide has recently been used effectively for the treatment of RA and may be useful for the management of patients with FS.

Antirheumatic Agents↗
PubMed2000

Use of unconventional methods of therapy by cancer patients in Pakistan.

Most of the studies related to the use of unconventional methods of therapy by cancer patients have been carried out in the developed countries. This study was conducted to ascertain the frequency, type, and duration of use of unconventional methods of therapy by cancer patients in Pakistan. We also wanted to identify individuals who are most likely to use these methods and to compare the findings with those reported from the developed countries. Between 1 April and 30 May 1994, all patients with histologically proven cancer who visited the oncology unit were interviewed. A printed questionnaire with questions and options was used as an interview guide. Informed consent was obtained. One hundred and ninety-one patients were interviewed, on average, for 25 minutes each. Use of unconventional methods of therapy by cancer patients was widespread (54.5% of all patients). The majority (83.7%) were influenced by family members to use these methods. Traditional herbal medicines (70.2%) and homeopathy (64.4%) were the most commonly employed methods. Thirty-six percent of the users employed these methods before receiving any conventional therapy. Only 15% used these methods after conventional therapeutic options had been exhausted. Patients generally perceived these methods as useful, non-toxic and inexpensive. Age, marital status, socio-economic background, education level and status of underlying neoplasm did not influence the frequency of use of unconventional methods. The use, however, was influenced by gender, family size, and type of underlying malignancy. Patients aware of their diagnosis were less likely to use these methods. This study suggests that use of unconventional methods by cancer patients in Pakistan is widespread. Unlike western countries, these methods are often employed before receiving any conventional therapy. This probably results in a significant delay which can be expected to adversely influence the subsequent disease management and survival. Public education, reduction of cost and easy availability of conventional therapy may be helpful in reducing the use of methods which otherwise may have no proven value.

Adolescent↗
PubMed1998

Isolated pulmonary cryptococcosis in pregnancy.

BACKGROUND: Isolated pulmonary cryptococcosis in an immunocompetent parturient host is a rare event. Little is known about this condition, its prognosis, and its treatment in the immunocompetent pregnant woman. CASE: A 28-year-old woman, para 3, was diagnosed with isolated pulmonary cryptococcosis postpartum. She had delivered a healthy neonate at term who revealed no clinical features compatible with maternal-fetal transmission. The woman was monitored closely throughout the course of her disease and radiogic, clinical, and serologic resolution was achieved after treatment with fluconazole. CONCLUSION: Patients with pulmonary cryptococcosis present with clinical pictures similar to other well-known diseases such as septic pulmonary emboli or choriocarcinoma. Treatment with triazole antifungal therapy yielded favorable results in our patient with this rare condition.

Adult↗
PubMed1998

Wiskott-Aldrich syndrome protein-deficient mice reveal a role for WASP in T but not B cell activation.

The Wiskott-Aldrich syndrome (WAS) is a human X-linked immunodeficiency resulting from mutations in a gene (WASP) encoding a cytoplasmic protein implicated in regulating the actin cytoskeleton. To elucidate WASP function, we disrupted the WASP gene in mice by gene-targeted mutation. WASP-deficient mice showed apparently normal lymphocyte development, normal serum immunoglobulin levels, and the capacity to respond to both T-dependent and T-independent type II antigens. However, these mice did have decreased peripheral blood lymphocyte and platelet numbers and developed chronic colitis. Moreover, purified WASP-deficient T cells showed markedly impaired proliferation and antigen receptor cap formation in response to anti-CD3epsilon stimulation. Yet, purified WASP-deficient B cells showed normal responses to anti-Ig stimulation. We discuss the implications of our findings regarding WASP function in receptor signaling and cytoskeletal reorganization in T and B cells and compare the effects of WASP deficiency in mice and humans.

Animals↗
PubMed1997

Endotoxin shock in antibody-deficient mice: unraveling the role of natural antibody and complement in the clearance of lipopolysaccharide.

While the significance of natural Ab is not entirely clear, one proposed role is clearance of bacterial Ags. To determine whether natural Ab was involved in clearance of endotoxin, we have examined novel strains of mice with either a total or selective deficiency in Ig. Recombinase-activating gene-2 (RAG-2(-/-))-deficient mice, which have no serum Ig due to arrested development of B cells at the pro-B stage, demonstrate increased sensitivity to endotoxin that correlates with an impaired clearance. When RAG-2(-/-) mice are reconstituted with pooled sera from normal mice, both survival and clearance of circulating endotoxin are enhanced. To further define the nature of the protective Ab, Bruton's tyrosine kinase (Btk)-deficient mice were characterized in the high dose LPS model. Like RAG-2(-/-) mice, they are highly sensitive to endotoxin and have an impaired clearance of LPS. Reconstitution of Btk(-/-) mice, which have reduced levels of IgG3 and IgM, with purified normal mouse IgM dramatically enhances their ability to clear endotoxin compared with mock (saline)-reconstituted littermates. The cellular source of natural anti-LPS IgM was identified as the peritoneal-residing B-1 cell by enzyme-linked immunospot (ELISPOT) assay. Taken together, these studies demonstrate the important role of natural Ab and complement in the clearance of pathogenic substances from the circulation.

Animals↗
PubMed1997

Radiotherapy-associated neutropenia and thrombocytopenia: analysis of risk factors and development of a predictive model.

Risk factors for unscheduled interruptions in radiotherapy courses completed between June 1989 and August 1995, lasting > or = 2 days, and associated with World Health Organization grade III-IV neutropenia or thrombocytopenia were studied retrospectively. A group of controls was randomly selected. Potential risk factors for myelosuppression were analyzed using univariate and multivariate analyses. The most important risk factors for treatment interruption with thrombocytopenia were concurrent chemotherapy (odds ratio [OR], 45.5; P < .001), increasing percentage of marrow irradiated (OR, 4.1 for each 20%; P < .001), and brain metastases (OR, 7.3; P = .01). Other significant (P < .05) factors were leukemia/lymphoma, bone or bone marrow metastases, and prior chemotherapy. The most important risk factors for treatment interruptions with neutropenia were concurrent chemotherapy (OR, 42.1; P < .001) and increasing percentage of marrow irradiated (OR, 3.3 for each 20%; P < .001). Similarly, the most important risk factors for treatment interruptions with both thrombocytopenia and neutropenia were concurrent chemotherapy (OR, 48.6; P < .001) and increasing percentage of marrow irradiated (OR, 3.9 for each 20%; P < .001). Other significant (P < .05) factors in these groups were bone marrow or brain metastases and previous chemotherapy. These data were used to create a model, assigning patients to groups at high, intermediate, or low risk for treatment interruption with thrombocytopenia. High-risk patients may be candidates for clinical trials of a platelet growth factor.

Adult↗
PubMed1997

Expression of hsc 70, but not hsp 70, in human third molar dental pulp.

The constitutive (hsc 70) and inducible (hsp 70) isoforms of heat shock protein 70 are important members of the superfamily of stress related proteins that protect and promote the recovery of cells from physiological and pathologic stress. The goal of this study was to define the baseline expression of hsc 70 and hsp 70 in disease-free, minimally stressed human dental pulp of the adult 3rd molar. Immunolocalization demonstrated moderate to heavy staining intensity for hsc 70 in both the cytoplasm and nucleus of odontoblasts and fibroblasts comprising the human pulp. Endothelial and smooth muscle cells displayed weak to moderate immunoreactivity for hsc 70 in both the cytoplasm and nucleus. Schwann cells demonstrated only weak nuclear staining for hsc 70. No immunoreactivity for hsp 70 was observed in any cell type in human pulp. Western, northern, and RT-PCR analysis of pulp preparations confirmed the expression of hsc 70 mRNA and protein within components of the pulp. These results demonstrate that cells of the human pulp express, under conditions of minimal stimulation, a key component of the stress response protein superfamily. The expression of hsc 70 under conditions of minimal stress may provide pulp components an advantage in resisting cell injury when stress occurs.

Adult↗
PubMed1996

Expression of heat shock protein 27 in developing and adult human kidney.

The expression of heat shock protein (hsp) 27 was examined in the developing and adult human kidney. Immunolocalization using a monoclonal antibody against human hsp 27 demonstrated immunoreactivity in both the developing and adult kidney. Low to moderate immunoreactivity for hsp 27 was observed in the fetal and adult proximal tubule, distal tubule, and mesangial cells of the glomeruli. Intense immunoreactivity for hsp 27 was localized to the cortical and medullary collecting ducts in both the adult and fetal kidney, with the most intense staining in the medullary regions. The loop of Henle demonstrated no immunoreactivity for hsp 27. The blastemal element of the developing kidney showed no hsp immunostaining and the ureteric bud demonstrated moderate staining. Western, northern, and reverse transcription-polymerase chain reaction (RT-PCR) analyses disclosed no significant differences in hsp 27 mRNA or protein level as a function of gestational age. An analysis of the phosphorylation state of hsp 27 showed the majority of hsp 27 to be present in the unphosphorylated isoform for both adult and fetal samples. These studies are the first to demonstrate the presence of hsp 27 in the human kidney. It is suggested that this pool of hsp 27 is constitutive as it appears in an inactivated state; localized to the cytoplasm and in an unphosphorylated state.

Adolescent↗