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Biomedical subjects

T A Khan

Publications and source records attributed to T A Khan.

At least 19 recordsLinked to original sources

Axillary and tympanic membrane temperature measurements are unreliable early after cardiopulmonary bypass.

BACKGROUND AND OBJECTIVE: Inaccurate measurements of body temperature following cardiopulmonary bypass may be associated with serious complications. The purpose of this study was to determine whether axillary and tympanic temperature measurements correlate with the urinary bladder temperature in the early postcardiac surgery period. METHODS: Forty-nine adult patients who underwent cardiac surgery under cardiopulmonary bypass at our institution were prospectively studied. Urinary bladder, right axillary, right tympanic and left tympanic temperature measurements were simultaneously recorded at 0, 6, 12 and 18 h following cardiopulmonary bypass. Patients had one to four sets of recordings and a total of 629 temperature measurements were recorded. The mean difference (bias) between the bladder and each of the other methods and limits of agreement were calculated using Bland and Altman method. RESULTS: The mean core body temperature recorded from the bladder on admission to the intensive care unit was 36.4 degrees C. After 6, 12 and 18 h the mean core body temperature was 37.4 degrees C (range: 35.2-39.0), 37.5 degrees C and 37.45 degrees C, respectively. The mean differences (bias) between the bladder temperature and the other three methods were: left tympanic, 0.65 degrees C (95% CI: -0.24 to 1.58); right tympanic, 0.57 degrees C (95% CI: -0.48 to 1.63) and right axillary, 0.55 degrees C (95% CI: -0.27 to 1.36). CONCLUSIONS: The axilla and tympanic membrane are unreliable sites for core body temperature measurement early after cardiopulmonary bypass in adult patients and clinical decisions should be based on more reliable methods.

Adult↗

Standardization of marketed Kumariasava--an Ayurvedic Aloe vera product.

Kumariasava is a marketed ayurvedic formulation containing Aloe vera as one of the main ingredients. Present study aims to standardize Kumariasava based upon chromatographic and spectral studies. Various extracts of Kumariasava have been prepared and evaluated. Chloroform extract indicated presence of three well-resolved fluorescent components. Spectral data of these three fractions (III-V) have been reported as a valuable analytical tool for routine standardization of Kumariasava. Fraction V indicated presence of anthraquinones, which is reported as the main constituent of aloe, namely aloin. Hence, isolation and evaluation of aloin has been undertaken. Aloin can be used as possible marker compound for standardization of Kumariasava.

Aloe↗

Risk factors for clinical infection in patients colonized with methicillin resistant Staphylococcus aureus (MRSA).

OBJECTIVE: To identify the risk factors involved in development of infection in individuals colonized with Methicillin-resistant Staphylococcus aureus (MRSA) among intensive care unit (ICU) patients. METHODS: A total of 1431 patients were admitted in ICU of which 63 grew MRSA during January 1998 to December 1999. Patients who developed infection with MRSA in less than 48 hours of their admission to ICU were excluded. Medical records of all patients who grew MRSA were reviewed and 57 patients were identified for inclusion in the study. Thirty-seven of these had features of infection with MRSA and were selected as cases and 20 were identified as asymptomatic colonizers and labeled as controls. Risk factors like age of the patient, duration of ICU stay, gender, co-morbidity, presence and duration of central lines, number of arterial-punctures and number and duration of intubations were compared between cases and controls. RESULTS: Cases were found to be significantly older (52.8 +/- 15.1) than controls (34.9 +/- 21.2). Other identified risk factors were diabetes mellitus (p = 0.001) and the first 15 days of central line placement (p = 0.025). Although chronic liver disease and hypertension could not be identified as significant risk factors, they clearly showed association. Other risk factors were not significantly different from controls. CONCLUSION: It is suggested that greater care is required for the elderly, diabetic patients with a central venous line in place especially during the first fifteen days of its introduction.

Age Distribution↗

Gene therapy progress and prospects: therapeutic angiogenesis for limb and myocardial ischemia.

After extensive investigation in preclinical studies and recent clinical trials, gene therapy has been established as a potential method to induce therapeutic angiogenesis in ischemic myocardial and limb disease. Advancements in viral and nonviral vector technology including cell-based gene transfer will continue to improve transgene transmission and expression efficiency. An alternative strategy to the use of transgenes encoding angiogenic growth factors is therapy based on transcription factors such as hypoxia-inducible factor-1alpha (HIF-1alpha) that regulate the expression of multiple angiogenic genes. Further understanding of the underlying biology of neovascularization is needed to determine the ability of growth factors to induce functionally significant angiogenesis in patients with atherosclerotic disease and associated comorbid conditions including endothelial dysfunction, which may inhibit blood vessel growth. The safety and tolerability of therapeutic angiogenesis by gene transfer has been demonstrated in phase I clinical trials. However, limited evidence of efficacy resulted from early phase II studies of angiogenic gene therapy for ischemic myocardial and limb disease. The utility of therapeutic angiogenesis by gene transfer as a treatment option for ischemic cardiovascular disease will be determined by adequately powered, randomized, placebo-controlled phase II and III clinical trials.

Animals↗

Vascular effects of spinal cord stimulation in the monkey.

Because of clinical reports suggesting beneficial effects of electrical stimulation in peripheral vascular disease, studies have been conducted in the monkey. Regional blood flow was measured prior to, during and following the application of electrical currents to the spinal cord. The flow measurements were made using radioactive microspheres. In addition, tissue temperatures and venous and arterial concentrations of epinephrine and norepinephrine were measured. The results show that electrical stimulation increases blood flow to the skin and muscle. It is hypothesized that the effect is due to sympathetic inactivation secondary to the application of electrical currents.

Animals↗

TNF-alpha and IL-6 expression in perfused rat liver after intraportal candidemia vs. E. coli or S. aureus bacteremia.

We tested the hypothesis that regulation of tumor necrosis factor-alpha (TNF-alpha) and IL-6 by the liver differs after intraportal challenge with Candida albicans spp. vs. gram-negative or gram-positive bacteria, independent of microbial clearance kinetics or hepatic O2 consumption (VO2). Buffer-perfused rat livers were infected with equivalent inocula (10(9) colony-forming units) of viable Escherichia coli serotype 055:B5 (EC), exotoxin C-producing Staphylococcus aureus (SA), or two strains of yeast phase C. albicans (CA-1 and CA-2). Microbial clearance and circulating cytokine levels were assessed over 180 min while monitoring VO2 and functional parameters, after which organ-based microbial killing, cell-associated TNF-alpha, and cytokine mRNA levels were determined. Compared with saline controls (normal saline solution; NSS), circulating and cell-associated TNF-alpha and TNF-alpha transcripts minimally increased after CA. In contrast, large increases in perfusate TNF-alpha occurred after EC, peaking at 180 min [135 +/- 32 U/ml (mean + SE)], concomitant with rises in cell-associated cytokine and TNF-alpha transcripts (P < 0.01 vs. NSS). Circulating TNF-alpha also rose after SA but neither cell-associated nor mRNA levels exceeded NSS values. There were no pathogen-specific differences in microbial clearance or VO2. IL-6 gene expression paralleled that for TNF-alpha, but IL-6 bioactivity in perfusates was inhibited by TNF-alpha-dependent and -independent mechanisms. We conclude that hepatic TNF-alpha and IL-6 expression are differentially regulated after taxonomically diverse microbial challenges, with E. coli eliciting the strongest and Candida spp. the weakest stimulatory responses.

Animals↗

A receptor for interleukin 10 is related to interferon receptors.

We isolated cDNAs encoding a mouse interleukin 10 receptor (mIL-10R) from mouse mast cell and macrophage cell lines. The two cDNAs are substantially identical and express an approximately 110-kDa polypeptide in COS7 cells, which binds mIL-10 specifically. A mouse pro-B-cell line (Ba/F3) expressing transfected recombinant mIL-10R binds IL-10 with high affinity (approximately 70 pM) and proliferates in response to mIL-10. mIL-10R is structurally related to interferon receptors (IFNRs). Since IL-10 inhibits macrophage activation by IFN-gamma, a possible implication of this relationship interaction of IL-10R and IFN-gamma R or their signaling pathways.

Amino Acid Sequence↗

Fluorescence in situ hybridization (FISH) of a whole-arm translocation involving chromosomes 18 and 20 with alpha-satellite DNA probes: detection of a centromeric DNA break?

Fluorescence in situ hybridization (FISH) with alpha-satellite DNA probes was used to study whole-arm chromosome translocation products in a family in which the propositus was shown to have a monosomy 18p/trisomy 20p imbalance. By this approach, we show that the chromosome 18 alpha-satellite DNA block is split into 2 smaller units, whereas the chromosome 20 breakpoint is not included within the alpha-satellite DNA region. We found no evidence to suggest that this split alpha-satellite DNA region has reduced or impaired the function of the centromere or that it contributed to the phenotype of the propositus. The FISH technique critically demonstrated the involvement of a whole-arm translocation in this case and provided accurate identification of breakpoints, which was not possible with standard banding techniques.

Abnormalities, Multiple↗

Structure of the mouse IL-10 gene and chromosomal localization of the mouse and human genes.

The nucleotide sequence of a 7.2-kb segment containing the mouse IL-10 (mIL-10) gene was determined. Comparison to the mIL-10 cDNA sequence (Moore, K. W., et al. 1990. Science 248:1230; 250:494) revealed the presence of five exons that span approximately 5.1 kb of genomic DNA. The noncoding regions of the mIL-10 gene contain sequences that have been associated with transcriptional regulation of several cytokine genes. The mIL-10 gene was mapped to mouse chromosome 1 and the human IL-10 gene was also mapped to human chromosome 1.

Amino Acid Sequence↗

Homology of cytokine synthesis inhibitory factor (IL-10) to the Epstein-Barr virus gene BCRFI.

Complementary DNA clones encoding mouse cytokine synthesis inhibitory factor (CSIF; interleukin-10), which inhibits cytokine synthesis by TH1 helper T cells, were isolated and expressed. The predicted protein sequence shows extensive homology with an uncharacterized open reading frame, BCRFI, in the Epstein-Barr virus genome, suggesting the possibility that this herpes virus exploits the biological activity of a captured cytokine gene to enhance its survival in the host.

Amino Acid Sequence↗

Renal functional response to dopamine during and after arteriography in patients with chronic renal insufficiency.

The potential renal vasodilatory effect of dopamine in improving renal function after arteriography was studied. Sixty patients with preexisting renal insufficiency were prospectively randomized into two groups. Patients in the treated group (n = 30) received an infusion of dopamine for 12 hours starting at the beginning of arteriography. Patients who received placebo infusion with arteriography (n = 30) served as controls. The study was conducted in two different time intervals. In the first interval, serum creatinine levels and 12-hour creatinine clearance values were obtained before and immediately after arteriography in 12 patients in the dopamine group and 13 patients in the control group. In the second interval, the same variables were measured before arteriography and for 3 consecutive days after arteriography in 18 patients in the dopamine group and 17 patients in the control group. Serum creatinine levels became significantly elevated in the control group on the 1st day and remained so on the 3rd day after arteriography, whereas the dopamine group did not show significant elevation of these levels. Creatinine clearance decreased in the control group on the 1st day, but this deterioration was not sustained on the 3rd day. In the dopamine group, there was no deterioration in creatinine clearance on either day, and mean effective renal plasma flow during and after arteriography was greater.

Aged↗