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Biomedical subjects

Amit K Ghosh

Publications and source records attributed to Amit K Ghosh.

At least 19 recordsLinked to original sources
PubMed2006

The association between impact factors and language of general internal medicine journals.

BACKGROUND: We sought to determine the associations between journal country of origin and language and journal impact factor of general medicine journals. METHODS: For each "Medicine, General and Internal" journal listed in the Institute for Scientific Information (ISI) Journal Citation Reports (JCR), the 2003 impact factor, language (ie, English, multiple languages [including English], or non-English), and country of origin (ie, US or non-US) were determined. The mean log impact factors of the journals by language, country of origin, and a combination of country of origin and language were compared. RESULTS: Of the 102 "Medicine, General and Internal" journals listed in the ISI JCR, 41 (40%) were published in the US and 83 (81%) were published in English. English-language journals had a significantly greater 2003 mean log impact factor than non-English journals and journals originating in the US had a significantly greater impact factor than journals originating elsewhere. However, the mean log impact factor of English-language journals originating in the US did not differ significantly from that of English-language journals originating elsewhere. CONCLUSION: Journal impact factor is more associated with journal language (ie, English versus non-English), rather than journal country of origin.

Bibliometrics↗
PubMed2006

Indolent systemic mastocytosis as the cause of a long history of unexplained hypotensive episodes.

Assessment of patients with unexplained hypotensive episodes in outpatient practice is often challenging, with an extensive differential diagnosis. The prevalence of systemic mast cell disease (MCD) is unknown, and the diagnosis is often elusive because serum and urine markers may become positive only after one of the self-limited, recurrent hypotensive episodes. Nevertheless, MCD is increasingly recognized as a cause of unexplained hypotension, secondary osteoporosis, and anaphylactic reactions to Hymenoptera stings. We describe a 38-year-old man who had a 15-year history of undiagnosed, recurrent hypotensive episodes with stereotypic symptoms. Extensive evaluation during these years was unrevealing. On physical examination, he appeared to be a healthy man with a prominent macular rash. Results of skin biopsy showed tryptase-positive mast cells. He had markedly elevated serum tryptase levels, and results of bone marrow biopsy revealed 10% mast cells; all these findings were consistent with indolent systemic mastocytosis. Key features in his history and physical examination prompted the conclusive testing. The most telling features were hypotension, tachycardia, and the rash (urticaria pigmentosa).

Adult↗
PubMed2004

Steric control of coordination number: A series of Mo(VI) dioxo diaryloxide complexes bearing 4-, 5-, and 6-coordinate environments.

The design, synthesis, and structure determination of a series of Mo(VI) dioxo diaryloxide complexes have been reported. By varying the steric bulk of the aryloxide ligand, control of the coordination number around the Mo(VI) center was achieved. All the complexes are characterized by analytical and spectroscopic techniques. Preliminary reactivity tests indicate that the 4-coordinate compound is the most stable and the 6-coordinate compound is the least stable.

Journal Article↗
PubMed2004

On the challenges of using evidence-based information: the role of clinical uncertainty.

Evidence-based medicine helps physicians appraise the latest and best evidence and incorporate patient's values in reaching a shared clinical decision. However, many decisions in medicine are made in the paucity of best evidence. Medical uncertainty remains inherent in clinical practice and contributes to significant variability in the way physicians and patients manage medical problems. Physicians and patients have varying degrees of tolerance for uncertainty. Intolerance to uncertainty among physicians results in increased test ordering tendencies, variability in medical treatment, failure to comply with evidence-based guidelines, and even guide career choices. Factors that result in the variability of physicians' interpretation of an effective treatment include: patient factors (prioritizing some factors over others), physician factors (lack of knowledge, lack of resources, medical uncertainty), and environmental factors (limitation of time and practice). Several approaches that have been found useful in implementing evidence in clinical practice include: sending reminders to prompt physicians to perform patient-related clinical activities, introducing computer information systems to support practice, and using interactive education interventions to teach newer skills and challenge negative attitudes. Passive educational approaches, like dissemination of guidelines and didactic lectures, are usually less useful in changing behavior. Among the techniques found to be useful for managing uncertainty are shared decision making, meticulous history taking, and physical examination, excluding worrisome differential diagnosis and establishing trust in patients. The role of future studies in assessing the outcome of multiple evidence-based strategies in situations of medical uncertainty remains to be explored.

Evidence-Based Medicine↗
PubMed2004

How reliable are assessments of clinical teaching? A review of the published instruments.

BACKGROUND: Learner feedback is the primary method for evaluating clinical faculty, despite few existing standards for measuring learner assessments. OBJECTIVE: To review the published literature on instruments for evaluating clinical teachers and to summarize themes that will aid in developing universally appealing tools. DESIGN: Searching 5 electronic databases revealed over 330 articles. Excluded were reviews, editorials, and qualitative studies. Twenty-one articles describing instruments designed for evaluating clinical faculty by learners were found. Three investigators studied these papers and tabulated characteristics of the learning environments and validation methods. Salient themes among the evaluation studies were determined. MAIN RESULTS: Many studies combined evaluations from both outpatient and inpatient settings and some authors combined evaluations from different learner levels. Wide ranges in numbers of teachers, evaluators, evaluations, and scale items were observed. The most frequently encountered statistical methods were factor analysis and determining internal consistency reliability with Cronbach's alpha. Less common methods were the use of test-retest reliability, interrater reliability, and convergent validity between validated instruments. Fourteen domains of teaching were identified and the most frequently studied domains were interpersonal and clinical-teaching skills. CONCLUSIONS: Characteristics of teacher evaluations vary between educational settings and between different learner levels, indicating that future studies should utilize more narrowly defined study populations. A variety of validation methods including temporal stability, interrater reliability, and convergent validity should be considered. Finally, existing data support the validation of instruments comprised solely of interpersonal and clinical-teaching domains.

Academic Medical Centers↗
PubMed2004

Impact of FUTON and NAA bias on visibility of research.

OBJECTIVE: To determine whether availability of journals on MEDLINE as FUTON (full text on the Net) affects their impact factor. MATERIAL AND METHODS: A comprehensive search identified 324 cardiology, nephrology, and rheumatology/immunology journals on-line until May 2003. The status of these journals was ascertained in MEDLINE as having FUTON, abstracts only, and NAA (no abstract available). Impact factors for all available journals from the Institute for Scientific Information (ISI) were abstracted. RESULTS: Of the 324 Journals, 124 (38.3%) were FUTON, 138 (42.6%) had abstracts only, and 62 (19.1%) had NAA. The mean (+/-SEM) impact factor was 3.24 (+/-0.32), 1.64 (+/-0.30), and 0.14 (+/-0.45), respectively. Of the 324 current journals, 159 existed in both the pre- and the post-Internet era. An analysis of the change (ie, delta) in impact factor from the pre- to post-Internet era revealed a trend between journals with FUTON and abstracts only (P=.17, Wilcoxon rank sum test). Similar analyses of the delta of cardiology journals revealed a statistically significant difference between Journals with FUTON and abstracts only (P=.04, Wilcoxon rank sum test). CONCLUSION: FUTON bias is the tendency to peruse what is more readily available. This is the first study to show that on-line availability of medical literature may increase the impact factor and that such increase tends to be greater in FUTON journals. Failure to consider this bias may affect a journal's impact factor. Also, it could limit consideration of medical literature by ignoring relevant NAA articles and thereby influence medical education akin to publication or language bias.

Abstracting and Indexing↗
PubMed2004

Dealing with medical uncertainty: a physician's perspective.

Uncertainty in diagnosis is frequently encountered in medical practice and causes stress in patients and physicians. Factors contributing to uncertainty include biological variability of patients, patient and physician bias, error in test interpretation, differing values and opinions of patients and physicians, and uncertainty surrounding decision-making. Physicians differ in their ability to tolerate uncertainty, and this varying tolerance has been linked with choice of specialty, increased test ordering, personal anxiety, increased cost of providing medical care, and decreased comfort with geriatric patients and patients with psychological problems. We review the current evidence for and effects of physician uncertainty in medical practice. Although uncertainty in practice cannot be completely eliminated, numerous strategies can be adopted to decrease uncertainty and enhance patients' trust. These include applying the best-available evidence-based information along with observance of core clinical practices, including meticulous history taking, excluding worrisome diagnoses, and involvement in shared decision-making.

Communication↗
PubMed2002

Metal-promoted aromatic ring amination and deamination reactions at a diazo ligand coordinated to rhodium and ruthenium.

Reactions of MCl(3).3H(2)O (M = Rh and Ru) with the ligand 2-[(2-N-arylamino)phenylazo]pyridine [HL(1); NH(4)C(5)N=NC(6)H(4)N(H)C(6)H(4)(H) (HL(1a)), NH(4)C(5)N=NC(6)H(4)N(H)C(6)H(4)(CH(3)) (HL(1b)), and NH(4)C(5)N=NC(6)H(4)N(H)C(5)H(4)N (HL(1c))] in the presence of dilute NEt(3) afforded multiple products. In the case of rhodium, two green compounds, viz. [Rh(L(1))(2)](+) ([2](+)) and [RhCl(pap)(L(1))](+) ([3](+)), where L(1) and pap stand for the conjugate base of [HL(1)] and 2-(phenylazo)pyridine, respectively, were separated on a preparative thin layer chromatographic plate. The reaction of RuCl(3).3H(2)O, on the other hand, produced two brown compounds, viz. [RuCl(HL(1))(L(1))] (4) and [RuCl(pap)(L(1))] (5), respectively, as the major products. The X-ray structures of the representative complexes are reported. Except for complex 2, and 4, the products are formed due to the cleavage of an otherwise unreactive C(phenyl)-N(amino) bond. In complex 4, one of the tridentate ligands (HL(1)) does not use its maximum denticity and coordinates as a neutral bidentate donor. Plausible reasons for the differences in their modes of coordination of the ligands as in 2 and 4 have been discussed. The ligand pap in the cationic mixed ligand complex [3](+) reacts instantaneously with ArNH(2) to produce an ink-blue compound, [RhCl(HL(2))(L(1))](+) ([6](+)) in a high yield. The ligand HL(2) is formed due to regioselective fusion of ArNH(2) residue at the para carbon of the phenyl ring (with respect to the azo fragment) of pap in [3](+). The above complexes are generally intensely colored and show strong absorptions in the visible region, which are assigned to intraligand charge transfer transitions. These complexes undergo multiple and successive one-electron-transfer processes at the cathodic potentials. Electrogenerated cationic complexes of ruthenium(III), [4](+) and [5](+), showed rhombic EPR spectra at 77 K.

Journal Article↗
PubMed2002

Photoinduced and chemical oxidation of coordinated imine to amide in isomeric osmium(II) complexes of N-arylpyridine-2-carboxaldimines. Synthesis, characterization, electron transfer properties, and structural studies.

The reaction of N-arylpyridine-2-carboxaldimine [C(5)H(4)NC(H)NC(6)H(4)R] (HL) with ammonium hexabromoosmate (NH(4))(2)[OsBr(6)] in boiling 2-methoxyethanol afforded a violet solution from which two geometrical isomers of [OsBr(2)(HL)(2)] (1 and 2) were isolated. These are characterized by analytical and spectroscopic data. (1)H NMR spectral data were used for the identification of the isomers. The blue-violet isomer, 1 (designated as ctc), has a 2-fold symmetry axis and gave rise to resonances for only one coordinated HL. The geometry of the ctc-isomer was, however, revealed from the X-ray structure determination of a representative example. The red-violet isomer (2, designated as ccc), on the other hand, is unsymmetrical and gave rise to a large number of proton resonances. The isomeric complexes, [OsBr(2)(HL)(2)], showed intense MLCT transitions in the visible region. This transition, in the ccc-isomer, is slightly (10 nm) red shifted in comparison to the ctc-isomer. These diimine complexes showed one metal based reversible oxidation assignable to the Os(III)/Os(II) process followed by two irreversible oxidations at more anodic potentials (>1.4 V). In addition to these, the complexes also showed two irreversible ligand reductions at high cathodic potentials (<-1.4 V). An unusual type of photochemical transformation of the azomethine function of coordinated HL in osmium compounds 1 is studied. When an air equilibrated acetonitrile solution of 1 was exposed to a xenon lamp, it underwent oxidation affording the mixed ligand, amido complexes of general formula [OsBr(2)(HL)(LO)], 3 (LO = C(5)H(4)NC(O)-N-C(6)H(4)R), in an excellent yield (>95%). This transformation (1 --> 3) was achieved chemically when H(2)O(2) was used as an oxidant. Notably, the chemical oxidation with H(2)O(2) also led to the formation of a tetravalent complex, [OsBr(2)(LO)(2)], 4, as a minor product. Compound 3 was characterized by various spectroscopic and analytical techniques. The room temperature magnetic moment of 3 corresponds to a t(2)(5) configuration for the osmium(III) center. EPR spectra of the amido complexes were recorded at 77 K in 1:1 dichloromethane-toluene glass, and they were anisotropic in nature. FAB mass spectra of 3 displayed intense peaks due to parent molecular ions. For example, the complex [OsBr(2)(HL(1))(L(1)O)], 3a, showed a strong peak at m/z 729 amu. The electronic spectrum of compound 3 consisted of a broad LMCT transition (ca. 525 nm; epsilon, 3000 M(-1) cm(-1)). The cyclic voltammogram of compound 3 consisted of two responses, one each on the positive and negative side of SCE, corresponding to Os(IV)/Os(III) (ca. 0.8V) and Os(III)/Os(II) (ca. -0.3V) couples, respectively. There has been a large cathodic shift of potential for the Os(III)/Os(II) couple in 3 in comparison to that in the parent complex, 1. The diamido compound [OsBr(2)(LO)(2)], 4, is diamagnetic and insoluble in common solvents. The X-ray structure determination of a representative sample, 4a, is reported. The molecule contains a C(2)-symmetry axis with bromide ions in relative cis positions. The Os-N(amide) bond lengths are considerably shorter than the Os-N(pyridine) lengths. All other bond lengths and angles fall within the expected range.

Journal Article↗