Peri-operative adrenocortical response to low-dose (1 microg) ACTH and relation to postoperative complications in patients undergoing elective abdominal surgery

BACKGROUND: To test the hypothesis that reduced responsiveness to adrenocorticotropin (ACTH) stimulation before elective major abdominal surgery is associated with an increased incidence of postoperative complications. METHODS: A low-dose (1 microg) ACTH test was performed the day before surgery, during the operation, on the first postoperative day, and before discharge from the hospital in 77 patients undergoing major abdominal surgery (age 62 [47;69] yrs [median, quartiles]; 30 female). Thirty-one patients undergoing minor, non-abdominal surgery (mostly inguinal hernia repair) (age 57 [40;66] yrs; 14 female) served as controls with minor surgical stress. A stimulated plasma cortisol concentration >or=500 nmol/l or an increment of >or=200 nmol/l in response to 1 microg ACTH was defined as normal. Scores for surgical stress and comprehensive risk, postoperative complications, and length of hospital stay (LOS) were assessed. RESULTS: On the day before major abdominal surgery, basal and stimulated plasma cortisol were 242 (165;299) nmol/l and 497 (404;568) nmol/l, respectively. Eighteen (23%) patients had an abnormal ACTH test, and 7 of these (39%) had complications versus 25 (42%) of the 59 patients with normal ACTH tests (P = .992). Surgical stress, comprehensive risk, and intra- and postoperative basal cortisol levels were higher and the response to ACTH stimulation smaller in patients with major abdominal compared to minor surgery. The peri-operative course of ACTH responses was not associated with complications or LOS in abdominal surgery patients. CONCLUSION: In patients scheduled for abdominal surgery, pre-operatively reduced adrenal response to stimulation with 1 microg ACTH is common but not associated with postoperative complications.

Foxo-mediated Bim transcription is dispensable for the apoptosis of hematopoietic cells that is mediated by this BH3-only protein

The BH3-only protein Bim is a critical initiator of apoptosis in hematopoietic cells. Bim is upregulated in response to growth factor withdrawal and in vitro studies have implicated the transcription factor Foxo3a as a critical inducer. To test the importance of this regulation in vivo, we generated mice with mutated Foxo-binding sites within the Bim promoters (Bim(ΔFoxo/ΔFoxo)). Contrary to Bim-deficient mice, Bim(ΔFoxo/ΔFoxo) mice had a normal hematopoietic system. Moreover, cytokine-dependent haematopoietic cells from Bim(ΔFoxo/ΔFoxo) and wt mice died at similar rates. These results indicate that regulation of Bim by Foxo transcription factors is not critical for the killing of hematopoietic cells.

IN-VIVO CT DOSIMETRY DURING VIRTUAL COLONOSCOPY

Virtual colonoscopy (VC) is a minimally invasive means for identifying colorectal polyps and colorectal lesions by insufflating a patient’s bowel, applying contrast agent via rectal catheter, and performing multi-detector computed tomography (MDCT) scans. The technique is recommended for colonic health screening by the American Cancer Society but not funded by the Centers for Medicare and Medicaid Services (CMS) partially because of potential risks from radiation exposure. To date, no in‐vivo organ dose measurements have been performed for MDCT scans; thus, the accuracy of any current dose estimates is currently unknown. In this study, two TLDs were affixed to the inner lumen of standard rectal catheters used in VC, and in-vivo rectal dose measurements were obtained within 6 VC patients. In order to calculate rectal dose, TLD-100 powder response was characterized at diagnostic doses such that appropriate correction factors could be determined for VC. A third-order polynomial regression with a goodness of fit factor of R2=0.992 was constructed from this data. Rectal dose measurements were acquired with TLDs during simulated VC within a modified anthropomorphic phantom configured to represent three sizes of patients undergoing VC. The measured rectal doses decreased in an exponential manner with increasing phantom effective diameter, with R2=0.993 for the exponential regression model and a maximum percent coefficient of variation (%CoV) of 4.33%. In-vivo measurements yielded rectal doses ranged from that decreased exponentially with increasing patient effective diameter, in a manner that was also favorably predicted by the size specific dose estimate (SSDE) model for all VC patients that were of similar age, body composition, and TLD placement. The measured rectal dose within a younger patient was favorably predicted by the anthropomorphic phantom dose regression model due to similarities in the percentages of highly attenuating material at the respective measurement locations and in the placement of the TLDs. The in-vivo TLD response did not increase in %CoV with decreasing dose, and the largest %CoV was 10.0%.

Transcriptional regulation of the human {\it PAX6\/} gene

PAX6, a member of the paired-type homeobox gene family, is expressed in a partially and temporally restricted pattern in the developing central nervous system, and its mutation is responsible for human aniridia (AN) and mouse small eye (Sey). The objective of this study was to characterize the PAX6 gene regulation at the transcriptional level, and thereby gain a better understanding of the molecular basis of the dynamic expression pattern and the diversified function of the human PAX6 gene.^ Initially, we examined the transcriptional regulation of the PAX6 gene by transient transfection assays and identified multiple cis-regulatory elements that function differently in different cell lines. The transcriptional initiation site was identified by RNase protection and primer extension assays. Examination of the genomic DNA sequence indicated that the PAX6 promoter has a TATA like-box (ATATTTT) at $-$26 bp, and two CCAAT-boxes are located at positions $-$70 and $-$100 bp. A 38 bp ply (CA) sequence was located 992 bp upstream from the initiation site. Transient transfection assays in glioblastoma cells and leukemia cells indicate that a 92 bp region was required for basal level PAX6 promoter activity. Gel retardation assays showed that this 92 bp sequence can form four DNA-protein complexes which can be specifically competed by a 31-mer oligonucleotide containing a PAX6 TATA-like sequence or an adenovirus TATA box. The activation of the promoter is positively correlated with the expression of PAX6 transcripts in cells tested.^ Based on the results obtained from the in vitro transfection assays, we did further dissection assay and functional analysis in both cell-culture and transgenic mice. We found that a 5 kb upstream promoter sequence is required for the tissue specific expression in the forebrain region which is consistent with that of the endogenous PAX6 gene. A 267 bp cell-type specific repressor located within the 5 kb fragment was identified and shown to direct forebrain specific expression. The cell-type specific repressor element has been narrowed to a 30 bp region which contains a consensus E-box by in vitro transfection assays. The third regulatory element identified was contained in a 162 bp sequence (+167 to +328) which functions as a midbrain repressor, and it appeared to be required for establishing the normal expression pattern of the PAX6 gene. Finally, a highly conserved 216 bp sequence identified in intron 4 exhibited as a spinal cord specific enhancer. And this 216 bp cis-regulatory element can be used as a marker to trace the differentiation and migration of progenitor cells in the developing spinal cord. These studies show that the concerted action of multiple cis-acting regulatory elements located upstream and downstream of the transcription initiation site determines the tissue specific expression of PAX6 gene. ^

Monitoring of threo-methylphenidate enantiomers in oral fluid by capillary electrophoresis with head-column field-amplified sample injection

Threo-methylphenidate is a chiral psychostimulant drug widely prescribed to treat attention-deficit hyperactivity disorder in children and adolescents. An enantioselective CE-based assay with head-column field-amplified sample stacking for analysis of threo-methylphenidate enantiomers in liquid/liquid extracts of oral fluid is described. Analytes are electrokinetically injected across a short water plug placed at the capillary inlet and become stacked at the interface between plug and buffer. Enantiomeric separation occurs within a few minutes in a pH 3.0 phosphate/triethanolamine buffer containing 20 mg/mL (2-hydroxypropyl)-β-CD as chiral selector. The assay with six point multilevel internal calibration provides a linear response for each enantiomer in the 10-200 ng/mL concentration range, is simple, inexpensive, and reproducible, and has an LOQ of 5 ng/mL. It was applied to oral fluid patient samples that were collected up to 12 h after intake of an immediate release tablet and two different extended release formulations with racemic methylphenidate. Drug profiles could thereby be assessed in a stereoselective way. Almost no levorotary threo-methylphenidate enantiomer was detected after intake of the two extended release formulations, whereas this enantiomer was detected during the first 2.5 h after intake of the immediate release preparation. The noninvasive collection of oral fluid is an attractive alternative to plasma for the monitoring of methylphenidate exposure in the pediatric community.

Glycosylation of TRPM4 and TRPM5 channels: molecular determinants and functional aspects

The transient receptor potential channel, TRPM4, and its closest homolog, TRPM5, are non-selective cation channels that are activated by an increase in intracellular calcium. They are expressed in many cell types, including neurons and myocytes. Although the electrophysiological and pharmacological properties of these two channels have been previously studied, less is known about their regulation, in particular their post-translational modifications. We, and others, have reported that wild-type (WT) TRPM4 channels expressed in HEK293 cells, migrated on SDS-PAGE gel as doublets, similar to other ion channels and membrane proteins. In the present study, we provide evidence that TRPM4 and TRPM5 are each N-linked glycosylated at a unique residue, Asn(992) and Asn(932), respectively. N-linked glycosylated TRPM4 is also found in native cardiac cells. Biochemical experiments using HEK293 cells over-expressing WT TRPM4/5 or N992Q/N932Q mutants demonstrated that the abolishment of N-linked glycosylation did not alter the number of channels at the plasma membrane. In parallel, electrophysiological experiments demonstrated a decrease in the current density of both mutant channels, as compared to their respective controls, either due to the Asn to Gln mutations themselves or abolition of glycosylation. To discriminate between these possibilities, HEK293 cells expressing TRPM4 WT were treated with tunicamycin, an inhibitor of glycosylation. In contrast to N-glycosylation signal abolishment by mutagenesis, tunicamycin treatment led to an increase in the TRPM4-mediated current. Altogether, these results demonstrate that TRPM4 and TRPM5 are both N-linked glycosylated at a unique site and also suggest that TRPM4/5 glycosylation seems not to be involved in channel trafficking, but mainly in their functional regulation.

Di genorṭe welṭ oder šwerer men nemṭ zich fir gringer helfṭ Goṭ : ašpagil naie windrlichi niṭšeche of Pûrîm ; wos hoṭ zich farlofin in ṭf maskwiṭer land ; tzum unṭerhalṭ far allerlei menṭšin gilernṭi in och imgilernṭi

Digitalisat der Ausg. Lemberg, 1865

Pfaffen-Mutz

Belagerung der Inselfestung im Jahre 1620