Ambulatory 24-hour esophageal pH monitoring

If 24-hour esophageal pH monitoring is to be a useful diagnostic tool, it must reliably discriminate gastroesophageal reflux patients despite daily variations in distal esophageal acid exposure. To address this issue, we studied 53 subjects (14 healthy normals, 14 esophagitis patients, and 25 patients with atypical symptoms) with two ambulatory pH tests performed within 10 days of each other. Intrasubject reproducibility of 12 pH parameters to discriminate the presence of abnormal acid reflux was determined. As a group, the parameters of percent time with pH<4 (total, upright, recumbent) were most reproducible (80%). Therefore, a subject was defined as having gastroesophageal reflux disease if at least one of these three values were abnormal. Intrasubject reproducibility for the diagnosis of reflux disease was 89% for the entire sample. Among subsets, the reproducibility was 93% for the normals and esophagitis patients and 84% for the atypical symptom patients. Total percent time with pH<4 was the single most discriminate pH parameter (85%) and nearly equaled that of the three combined parameters (89%). The intrasubject variability of this parameter was determined by the mean ±2sd of the relative differences between the two test results for all 53 subjects. Total percent time with pH<4 may vary between tests by a factor of 3.2-fold or less (218% higher to 69% lower). We conclude: (1) ambulatory 24-hr esophageal monitoring is a reproducible test for the diagnosis of gastroesophageal reflux disease; and (2) the large intrastudy variability in 24-hr total acid exposure may limit this test's usefulness as a measurement of therapeutic improvement.Supported, in part, by Public Health Services Grant AM 34200-01A1 from NIADDIK.     

Patients' recollections of therapeutic paralysis in the intensive care unit.

BACKGROUND: Neuromuscular blocking agents used for therapeutic purposes, such as facilitating mechanical ventilation and relieving life-threatening agitation, paralyze patients but leave them fully conscious. Aggressive sedation or analgesia is necessary to reduce awareness, relieve fear, produce comfort, decrease anxiety, induce unconsciousness, and minimize possible complications such as posttraumatic stress syndrome. Little information is available on the extent to which patients experience awareness during therapeutic paralysis. OBJECTIVES: To determine and describe the remembered experiences of critical care patients who were given neuromuscular blocking agents and sedatives and/or analgesics to facilitate mechanical ventilation, improve hemodynamic stability, and improve oxygenation. METHODS: A phenomenological approach with in-depth interviews with 11 patients was used. Data were analyzed by using the constant comparative approach. RESULTS: A total of 4 themes and 3 subthemes were identified. The first theme was back and forth between reality and the unreal, between life and death; the subtheme was having weird dreams. The second theme was loss of control; the 2 subthemes were (1) fighting or being tied down and (2) being scared. The third theme was almost dying, and the fourth theme was feeling cared for. CONCLUSIONS: Patients can remember having both negative and positive experiences during neuromuscular blockade. Steps to improve the experiences of patients receiving neuromuscular blockers include improving assessment parameters, developing and using sedation/analgesia guidelines, and investing in quality improvement programs to provide assessment of awareness during therapeutic paralysis and follow-up and referral as necessary. Ways to decrease the use of neuromuscular blockers would also be useful.     

A prospective, randomized, cross-over comparison of two methods of artificial insemination by donor on the incidence of conception: intracervical insemination by straw versus cervical cap

In a prospective, randomized study of insemination with donor semen, intracervical insemination by straw was compared with insemination using a cervical cap with an intracervical reservoir. A total of 91 patients completed 486 treatment cycles. There were no significant differences in age, parity, indication for insemination by donor, or method of cycle monitoring between women who became pregnant and those who did not conceive with either insemination method. In 236 standard intracervical insemination cycles, 14 patients became pregnant (5.9% per cycle), whereas 38 patients conceived in 250 cervical cap cycles (15.2% per cycle). Both the crude pregnancy rates and the cumulative pregnancy rates calculated by the Kaplan-Meier life-table method were significantly different (chi(2)-test, P < 0.001, and log-rank test, P < 0.005 respectively). Pregnancy rates in artificial insemination with cryopreserved donor semen may be improved by the use of a cervical cap when compared to cervical insemination by straw. The use of the cervical cap may prolong the exposure of the spermatozoa to the cervical mucus and prevent the backflow of semen into the vagina.      

In vivo and in vitro studies of the site of inhibitory action of omeprazole on adrenocortical steroidogenesis

Summary The site of omeprazole inhibition of adrenal steroidogenesis has been sought in vivo by analyzing the patterns of urinary steroid metabolite excretion after 6 days of treatment with placebo/omeprazole.Excretion rates of androsterone, aetiocholanolone, dehydroepiandrosterone, 11 hydroxyandrosterone, tetrahydrocortisone, tetrahydrocortisol and cortolone were reduced, indicating a block at an early step in steroidogenesis, possibly cholesterol side-chain cleavage. In vitro studies have confirmed this finding by measuring conversion of added precursors to cortisol in isolated bovine adrenocortical cells. Cortisol synthesis from added 20 hydroxycholesterol was inhibited by 83% in the presence of 100 µg omeprazole/ml. Conversion from pregnenolone and progesterone and their 17 hydroxylated derivatives was inhibited by 20–40% whereas cortisol production from added 11 deoxycortisol was not affected.These data suggest that omeprazole primarily inhibits cholesterol cleavage and does not inhibit 3 hydroxysteroid dehydrogenase, 17 hydroxylase or 11 hydroxylation; 21 hydroxylase activity may be marginally attenuated.     

A cAMP-activated chloride channel in the plasma membrane of cultured human gastric cells (HGT-1)

Hydrochloric acid (HCl) secretion by gastric parietal cells involves an apical Cl^– conductance, the properties of which have not been defined. In the present study, forskolin and histamine [agonists that increase intracellular cyclic adenosine monophosphate (cAMP)], and dibutyryl cAMP, activated channels in previously quiescent cell-attached membrane patches on cultured human gastric cells (HGT-1). In the cell-attached configuration (Cl^–149 mmol/ 1 in bath and pipette), channels exhibited outward rectification, voltage dependence, inward current (–0.7 pA) at zero holding potential and a reversal potential of +24 mV, consistent with the presence of a Cl^– conductive pathway. In excised inside-out patches, channels (i) exhibited degrees of outward rectification and voltage dependence that were comparable to those seen in cell-attached patches, (ii) demonstrated a –21 mV shift of their reversal potential when bath Cl^– was decreased from 149 mmol/l to 53 mmol/l (calculated Cl^–:cation permeability ratio 171), and (iii) were highly sensitive to the Cl^– channel blocker diphenylamine-2-carboxylic acid (DPC, 10^–3 mol/l). This cAMP-activated Cl^– channel bears many similarities to other Cl^– channels within intestinal epithalia, and may represent the apical Cl^– channel operating in HCl-secreting gastric parietal cells.     

Genetic analysis and attribution of microbial forensics evidence

Because of the availability of pathogenic microorganisms and the relatively low cost of preparing and disseminating bioweapons, there is a continuing threat of biocrime and bioterrorism. Thus, enhanced capabilities are needed that enable the full and robust forensic exploitation and interpretation of microbial evidence from acts of bioterrorism or biocrimes. To respond to the need, greater resources and efforts are being applied to the burgeoning field of microbial forensics. Microbial forensics focuses on the characterization, analysis and interpretation of evidence for attributional purposes from a bioterrorism act, biocrime, hoax or inadvertent agent release. To enhance attribution capabilities, a major component of microbial forensics is the analysis of nucleic acids to associate or eliminate putative samples. The degree that attribution can be addressed depends on the context of the case, the available knowledge of the genetics, phylogeny, and ecology of the target microorganism, and technologies applied. The types of genetic markers and features that can impact statistical inferences of microbial forensic evidence include: single nucleotide polymorphisms, repetitive sequences, insertions and deletions, mobile elements, pathogenicity islands, virulence and resistance genes, house keeping genes, structural genes, whole genome sequences, asexual and sexual reproduction, horizontal gene transfer, conjugation, transduction, lysogeny, gene conversion, recombination, gene duplication, rearrangements, and mutational hotspots. Nucleic acid based typing technologies include: PCR, real-time PCR, MLST, MLVA, whole genome sequencing, and microarrays.