Antibiotic usage in appendicitis in children.
Explore the source record for details and available documents.
Anti-Bacterial Agents↗
Biomedical subjects
S Kaplan
Publications and source records attributed to S Kaplan.
Control of photosystem formation in Rhodobacter sphaeroides.
Explore the source record for details and available documents.
Gene Expression Regulation, Bacterial↗
Cascade regulation of dimethyl sulfoxide reductase (dor) gene expression in the facultative phototroph Rhodobacter sphaeroides 2.4.1T.
Under anaerobic-dark growth conditions, in the presence of the alternative electron acceptor dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO), Rhodobacter sphaeroides 2.4.1(T) respires anaerobically using the molybdoenzyme DMSO reductase (DMSOR). Genes encoding DMSOR and associated proteins are encoded by genes of the dor locus. Previously, we demonstrated that the expression of DMSOR is regulated by both the oxygen status of the cell via the FnrL protein and by the presence of DMSO or TMAO, presumably through the DorS-DorR two-component sensor-regulator system. Here we further investigate expression of the dor genes through the use of transcriptional lacZ fusions to the dorS, dorR, and dorC promoters. The expression of dorC::lacZ was strongly induced by the absence of oxygen and presence of DMSO. In accordance with our previous findings of DMSOR activity, dorC::lacZ expression was reduced by up to one-third when cells were grown photosynthetically in the presence of DMSO with medium or high light, compared to the expression observed after anaerobic-dark growth. The induction of dorC::lacZ expression in the presence of DMSO was dependent on the DorS and DorR proteins. Expression of the dorS and dorR genes was also induced in the absence of oxygen. In an FnrL mutant, dorS::lacZ expression was not induced when oxygen tensions in the media were lowered, in contrast to what occurred in the wild-type strain. The expression of dorS::lacZ and dorR::lacZ was dependent on the DorS and DorR proteins themselves, suggesting the importance of autoregulation. These results demonstrate a cascade regulation of dor gene expression, where the expression of the regulatory proteins DorS and DorR governs the downstream regulation of the dorCBA operon encoding the structural proteins of DMSOR.
Anaerobiosis↗
A redox-responsive pathway for aerobic regulation of photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1.
To further understand the proposed signal transduction pathway involving the presumed redox proteins RdxBH and cbb3 cytochrome oxidase in Rhodobacter sphaeroides 2.4.1, a series of mutants lacking components of both the Prr two-component activation system and the cbb3-type cytochrome oxidase or RdxBH were constructed. We report that under highly aerobic conditions, aberrant photosynthesis gene expression and spectral complex formation typical of cbb3- or RdxBH-deficient mutants were no longer observed when either prrA (encoding the response regulator of the Prr system) or prrB (encoding the presumed sensor kinase) was also deleted. These double-mutant strains are phenotypically identical to single-mutant PrrA and PrrB strains, suggesting that the signal(s) originating from the cbb3 terminal oxidase affects downstream puc and puf operon expression by acting exclusively through the Prr system. When the same double-mutant strains were examined under anaerobic dark dimethyl sulfoxide growth conditions, photosynthesis gene expression was obligatorily linked to the two-component activation system. However, photosynthesis gene expression under the same growth conditions was significantly higher in the cbb3 mutant strain when compared to that in the wild type. Similarly, under anaerobic photosynthetic conditions the high levels of the oxidized carotenoid, spheroidenone, which accumulate in cbb3-deficient mutants were nearly restored to normal in a PrrB- CcoP- double mutant. This observation, together with previously published results, suggests that the regulation of the CrtA-catalyzed reaction possesses both transcriptional and posttranscriptional regulatory effectors. We propose that the cbb3 cytochrome oxidase, which by definition can interact with external oxygen, serves to control the activity of the Prr two-component activation system under both aerobic and anaerobic conditions. Although independent from the cbb3 oxidase, the RdxBH proteins are also required for normal functioning of the Prr two-component activation system and are therefore believed to lie between the cbb3 oxidase in this oxygen-sensing, redox signaling pathway and the Prr activation system.
Aerobiosis↗
Redox-dependent gene regulation in Rhodobacter sphaeroides 2.4.1(T): effects on dimethyl sulfoxide reductase (dor) gene expression.
The ability of Rhodobacter sphaeroides 2.4.1(T) to respire anaerobically with the alternative electron acceptor dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO) is manifested by the molybdoenzyme DMSO reductase, which is encoded by genes of the dor locus. Previously, we have demonstrated that dor expression is regulated in response to lowered oxygen tensions and the presence of DMSO or TMAO in the growth medium. Several regulatory proteins have been identified as key players in this regulatory cascade: FnrL, DorS-DorR, and DorX-DorY. To further examine the role of redox potentiation in the regulation of dor expression, we measured DMSO reductase synthesis and beta-galactosidase activity from dor::lacZ fusions in strains containing mutations in the redox-active proteins CcoP and RdxB, which have previously been implicated in the generation of a redox signal affecting photosynthesis gene expression. Unlike the wild-type strain, both mutants were able to synthesize DMSO reductase under strictly aerobic conditions, even in the absence of DMSO. When cells were grown photoheterotrophically, dorC::lacZ expression was stimulated by increasing light intensity in the CcoP mutant, whereas it is normally repressed in the wild-type strain under such conditions. Furthermore, the expression of genes encoding the DorS sensor kinase and DorR response regulator proteins was also affected by the ccoP mutation. By using CcoP-DorR and CcoP-DorY double mutants, it was shown that the DorR protein is strictly required for altered dor expression in CcoP mutants. These results further demonstrate a role for redox-generated responses in the expression of genes encoding DMSO reductase in R. sphaeroides and identify the DorS-DorR proteins as a redox-dependent regulatory system controlling dor expression.
Bacterial Proteins↗
Role of the fnrL gene in photosystem gene expression and photosynthetic growth of Rhodobacter sphaeroides 2.4.1.
Anoxygenic photosynthetic growth of Rhodobacter sphaeroides 2.4.1 requires a functional fnrL gene, which encodes the anaerobic regulator, FnrL. Using transcriptional fusions to the puc operon in which the upstream FNR consensus-like sequence is either present or absent, we obtained results that suggest that FnrL has both a direct and an indirect role in puc operon expression. In addition to FnrL, several other factors, including the two-component Prr regulatory system and the transcriptional repressor PpsR, are known to mediate oxygen control of photosynthesis gene expression in this organism. Therefore, we examined the relationship between FnrL and these other regulatory elements. Our results indicate that while mutations of prr or ppsR can lead to an increase in expression of some photosynthesis genes under aerobic and anaerobic conditions, regardless of the presence or absence of FnrL, there remains an absolute requirement for a functional fnrL gene for photosynthetic growth. We examined the potential role(s) of FnrL in photosynthetic growth by considering several target genes which may be required for this growth mode.
Aerobiosis↗
Oxygen regulation of the ccoN gene encoding a component of the cbb3 oxidase in Rhodobacter sphaeroides 2.4.1T: involvement of the FnrL protein.
The ccoNOQP gene cluster of Rhodobacter sphaeroides 2.4.1T encodes a cbb3 cytochrome oxidase which is utilized in oxygen-limited conditions for aerobic respiration. The beta-galactosidase activity of a ccoN::lacZ transcriptional fusion was low under high (30%)-oxygen and anaerobic growth conditions. Maximal ccoN::lacZ expression was observed when the oxygen concentration was lowered to 2%. In an FnrL mutant, ccoN::lacZ expression was significantly lower than in the wild-type strain, suggesting that FnrL is a positive regulator of genes encoding the cbb3 oxidase.
Aerobiosis↗
FEESST: a new bedside endoscopic test of the motor and sensory components of swallowing.
We here introduce an office or bedside method of evaluating both the motor and sensory components of swallowing, called fiberoptic endoscopic evaluation of swallowing with sensory testing (FEESST). FEESST combines the established endoscopic evaluation of swallowing with a technique that determines laryngopharyngeal (LP) sensory discrimination thresholds by endoscopically delivering air pulse stimuli to the mucosa innervated by the superior laryngeal nerve. Endoscopic assessment of LP sensory capacity followed by endoscopic visualization of deglutition was prospectively performed 148 times on 133 patients with dysphagia over an 8-month period. The patients had a variety of underlying diagnoses, with stroke and chronic neurologic disease predominating (n = 94). Subsequent to LP sensory testing, a complete dysphagia evaluation was conducted. Various food and liquid consistencies were dyed green, and attention was paid to their management throughout the pharyngeal stage of swallowing. Evidence of latent swallow initiation, pharyngeal pooling and/or residue, laryngeal penetration, laryngeal aspiration, and/or reflux was noted. Recommendations for therapeutic intervention were based on information obtained during the FEESST and often involved the employment of compensatory swallowing strategies, modification of the diet or its presentation, placement on non-oral feeding status, and/or referral to other related specialists. All patients successfully completed the examination. In 111 of the evaluations (75%), severe (>6.0 mm Hg air pulse pressure [APP]) unilateral or bilateral LP sensory deficits were found. With puree consistencies, 31% of evaluations with severe deficits, compared to 5% of evaluations with either normal sensitivity or moderate (4.0 to 6.0 mm Hg APP) LP sensory deficits, displayed aspiration (p < .001, chi2 test). With puree consistencies, 69% of evaluations with severe deficits, compared to 24% with normal or moderate deficits, displayed laryngeal penetration (p < .001, chi2 test). FEESST allows the clinician to obtain a comprehensive bedside assessment of swallowing that is performed as the initial swallowing evaluation for the patient with dysphagia.
Adult↗
The compensatory anti-inflammatory cytokine interleukin 10 response in pediatric sepsis-induced multiple organ failure.
STUDY OBJECTIVES: To determine the circulating anti-inflammatory cytokine interleukin 10 (IL-10) response during the development of sepsis-induced multiple organ failure in children. DESIGN: Prospective study. SETTING: University pediatric ICU. PATIENTS: Fifty-three consecutive children with sepsis and 15 critically ill children without sepsis. INTERVENTIONS: Plasma IL-10, interleukin 6 (IL-6), and nitrite+nitrate (stable end products of nitric oxide) levels and an organ failure index (OFI indicating the number of failing organ systems) were determined in 53 children on days 1 to 3 of sepsis and in control children on day 1. The effect of exogenous human IL-10 or neutralizing IL-10 antibody on supernatant IL-6 levels in ex vivo whole blood culture from 17 children on day 1 of sepsis. MEASUREMENTS AND RESULTS: Children with three or more organ failures had higher plasma IL-10 levels than children with less than 3 organ failures (days 1 and 3; p<0.05). Children who developed sequential pulmonary/hepatic/renal failure had higher IL-10 levels (days 1 to 3; p<0.05). Nonsurvivors had higher IL-10 levels (day 3; p<0.05). IL-10 levels correlated with IL-6 levels (days 1 and 2) and nitrite+nitrate levels (days 1 and 3; p<0.05). Whole blood samples incubated ex vivo with exogenous recombinant human IL-10 had decreased supernatant IL-6 levels (p<0.05) and neutralizing IL-10 antibody showed no significant effect. CONCLUSION: A persistent compensatory anti-inflammatory cytokine response characterizes sepsis-induced multiple organ failure. Administration of exogenous IL-10 may inhibit the early proinflammatory response; however, identification of individual immune responsiveness and possibility of persistent infection could be important to rational use in the later stages of pediatric sepsis.
Adolescent↗
The importance of the therapeutic alliance.
BACKGROUND: A review of classic and contemporary literature in the field of psychotherapy shows potential correspondence between the relationships of psychotherapists and optometrists to their patients. Much of the help that a doctor in any specialty offers to a patient is emotional. The doctor's nonjudgmental attitude, warmth, respect, reassurance, and willingness to listen can promote a healthy patient-doctor relationship and, in turn, that therapeutic alliance is important for the patient's compliance with treatment plans. METHODS: Although the nonpsychotherapist should never extend treatment into any activity that could be called psychotherapy, an optometrist must nevertheless consider and recognize factors in diagnosis and treatment. The optometrist needs to listen closely to a patient's concerns and provide objective information about his or her condition. An eye examination must span several disciplines--including psychology, sociology, linguistics, phonetics, and disclosure analysis, lest the optometrist misinterpret or discount what the patient says. CONCLUSION: Responding to the psychological aspects of visual impairment is part of a humane treatment program, and showing genuine empathy is central to the effectiveness of therapy.
Eye Diseases↗
Nutritional factors in the etiology of brain tumors: potential role of nitrosamines, fat, and cholesterol.
Several possible risk factors for brain tumors have been suggested in the past, including N-nitroso compounds, but with the exception of ionizing radiation, none has been consistently confirmed. The present study was aimed at assessing the influence of nutritional factors, including N-nitroso compounds, in the etiology of brain tumors, specifically gliomas and meningiomas. One hundred and thirty-nine cases with confirmed brain tumors diagnosed between 1987 and 1991 in central Israel and 278 controls matched according to age, sex, and ethnic origin were interviewed. Nutritional data were obtained using a semiquantitative food frequency approach. A significant positive association for both types of brain tumors was found with high protein intake (odds ratio (OR) = 1.94, 95% confidence interval (CI) 1.03-3.63), while intake of sodium was inversely related to both types of brain tumors (OR = 0.52, 95% CI 0.31-0.87). Increased consumption of total fat and cholesterol was inversely related to gliomas (high intake of fat: OR = 0.45, 95% CI 0.20-1.07; high intake of cholesterol: OR = 0.38, 95% CI 0.14-1.01). However, neither fat intake nor cholesterol intake was significantly related to the risk of meningiomas. Although N-nitroso compounds were not found to be directly associated with brain tumors, the data suggested the presence of an interaction between the effects of N-nitroso compounds and protein intake and between N-nitroso compounds and cholesterol intake. The data suggest that dietary factors may play an important, though yet undefined, role in the development of brain tumors.
Adolescent↗
Biochemical markers of myocardial injury in children.
Explore the source record for details and available documents.
Anthracyclines↗
A mammalian mitochondrial drug receptor functions as a bacterial "oxygen" sensor.
The rat mitochondrial outer membrane-localized benzodiazepine receptor (MBR) was expressed in wild-type and TspO- (tryptophan-rich sensory protein) strains of the facultative photoheterotroph, Rhodobacter sphaeroides 2.4.1, and was shown to retain its structure within the bacterial outer membrane as assayed by its binding properties with a variety of MBR ligands. Functionally, it was able to substitute for TspO by negatively regulating the expression of photosynthesis genes in response to oxygen. This effect was reversed pharmacologically with the MBR ligand PK11195. These results suggest a close evolutionary and functional relationship between the bacterial TspO and the MBR. This relationship provides further support for the origin of the mammalian mitochondrion from a "photosynthetic" precursor. Finally, these findings provide novel insights into the physiological role that has been obscure for the MBR in situ.
Amino Acid Sequence↗
Anaerobic carotenoid biosynthesis in Rhodobacter sphaeroides 2.4.1: H2O is a source of oxygen for the 1-methoxy group of spheroidene but not for the 2-oxo group of spheroidenone.
Anaerobic biosynthesis of carotenoids in the purple facultative photosynthetic bacterium Rhodobacter sphaeroides was studied using mass spectrometry. We have demonstrated that (18)O from H2(18)O was incorporated into the 1-methoxy group of spheroidene and spheroidenone, the two major carotenoids produced by this bacterium during photosynthetic growth. Neither water nor CO2 was shown to provide an oxygen atom for the 2-oxo group of spheroidenone in R. sphaeroides 2.4.1 grown photosynthetically in the absence of molecular oxygen. Possible mechanisms for the anaerobic biosynthesis of spheroidenone in R. sphaeroides are discussed.
Anaerobiosis↗
Occupational risks for the development of brain tumors.
Occupationally related risk factors were assessed in a population-based, case-control study of 139 patients with primary brain tumors (BT), carried out in central Israel between 1987-1991. For each case, two control groups were matched by age (+/-5 years), sex, and ethnic origin. The interview schedule included questions about lifelong occupational history before diagnosis. Odds ratios (OR) for BT, according to industrial categories, showed a significantly increased risk among blue-collar workers, especially among those employed in the textile industry, and among drivers and motor vehicle operators. When histologic tumor types were assessed separately, a significantly increased risk for malignant BT was found among drivers and motor vehicle operator occupations, while for meningiomas, an increased risk was found among weavers and tailors. Our results may provide clues for etiology and prevention measures.
Adult↗
Partial growth-hormone insensitivity: the role of growth-hormone receptor mutations in idiopathic short stature.
Mutations in the GHR locus may play a role in the cause of idiopathic short stature (ISS) by impairing growth-hormone (GH) receptor (GHR) function. At one extreme, mutations that nullify the function of the GH receptor are linked to complete GH insensitivity syndrome, or Laron syndrome, and we hypothesized that less-disruptive mutations could contribute to partial GH insensitivity syndrome. Low levels of GH binding protein may indicate mutations in the extracellular domain of the receptor, and by focusing on 14 children with ISS who had low GH binding protein and insulin-like growth factor I levels, we found three heterozygotes and one compound heterozygote for mutations in the extracellular domain of the receptor. We have since extended our study to a broader spectrum of patients, adding 76 patients with ISS who were treated with GH in a phase II study of the safety and efficacy of recombinant human GH in ISS and also adding 10 patients who were ascertained as having ISS by pediatric endocrinologists in private practice. The GHR gene has thus been analyzed in 100 patients with ISS, eight of whom were found to carry mutations: four in our original study and four with normal or elevated levels of GH binding protein. The latter group consists of three carriers of heterozygous extracellular domain mutations and one carrier of a heterozygous intracellular domain mutation. Family data suggest that the carriers of these mutations have a range of phenotypes, supporting our hypothesis that the expression of these heterozygous mutations as partial GH insensitivity syndrome depends on the genetic makeup of the person.
Body Height↗
The possible meaning of the upper and lower alpha frequency ranges for cognitive and creative tasks.
This study is aimed at verifying the functional independence of two frequency bands within the alpha range. It is based on experiments that examined the role of these two hands with regard to the amount of local electrogenesis (amplitude) and the cooperation of brain areas (coherence) in mental tasks concerning: (1) visual perception and imagery; (2) listening to and composing music; (3) verbal and visual creativity; and (4) aspects of mood. In all experiments EEG were recorded for at least 1 min during each task, separated one from another by at rest periods of at least equal lengths. EEG electrodes were pasted according to the 10/20 system (averaged ear lobes as reference). After FFT power was calculated for all 19 electrodes, coherence was estimated for all possible electrode pairs (i.e. 171). This was done for six frequency ranges between 1.5 and 31.5 Hz, the alpha range having been divided into two (7.5-9 Hz and 9.5-12.5 Hz). The spectral parameters obtained during each task were compared with those of the merged EEG at rest, significant changes (P < or = 0.01-P < or = 0.05) were entered into schematic maps of the brain. Generally, fewer differences were found for amplitude than for coherence. In all four tasks concerning visual perception the clearest differences were found in single person studies. But also in group studies more or less distinct differences were found between alpha 1 and 2. Also in the series with music the two alpha bands did not behave uniformly, nor were uniform features found in the two series of musically trained and untrained subjects. Distinct discrepancies were also found in a verbal and visual imagery task. With respect to mood, only elevated mood was correlated with a decrease of coherence in alpha 2 and an increase of amplitude in alpha 1. This study though hinting at a different functional significance of these two alpha bands, however, does not allow to draw any conclusions as to their distinct functional meanings. Generally, the long-term coherence changes observed under these different mental tasks support the idea that part of information processing in the brain is reflected by the EEG. Structural peculiarities and microelectrode recordings of the cortex support this conclusion.
Adult↗
Implant site influence on arterial prosthesis healing: a comparative study with a triple implantation model in the same dog.
PURPOSE: The purpose of this study was to develop a cost-effective canine graft healing model that gives information on various implant sites and controls for variable factors between graft locations and between animals and to compare the influence of implant site (retropleural, retroperitoneal, and subcutaneous areas) on arterial graft healing in the same subject under such controlled study conditions. METHODS: Five mongrel dogs were studied for 8 weeks, and one was studied for 3 years. Each received three porous Dacron grafts during the same surgery: a carotid-femoral bypass (C-FB) and interposition grafts in the descending thoracic aorta and abdominal aorta. To produce comparable shear stress calibers of the C-FB and abdominal aorta grafts were 2 mm less than those of the descending thoracic aorta, and a distal arterio-venous fistula was created to further increase the C-FB flow. For comparable blood aggregation status platelet aggregation was preevaluated and adjusted with antiplatelet agents. Graft flow surfaces were assessed for thrombus-free surface and endothelial-like cell coverage scores. Tissue samples were studied with hematoxylin-eosin, factor VIII/ von Willebrand factor, smooth muscle alpha-actin staining, and scanning electron microscopy and transmission electron microscopy. RESULTS: All grafts were patent. Shear stress for the three grafts and platelet aggregation among the study subjects were comparable. Healing of descending thoracic aorta and abdominal aorta grafts was similar, but C-FB healing was slow, incomplete, and uneven, with a high incidence of seroma. Eight-week and 3-year results were comparable. CONCLUSIONS: This model gives broad healing information about the areas where grafts are often implanted in humans. Eight weeks appears to be a sufficient period to reflect basic and general healing characteristics. Grafts heal better in the retropleural and retroperitoneal areas than in the subcutaneous tissues.
Animals↗