Type I second-degree AV block (Mobitz type I, Wenckebach AV block) during ritodrine therapy for preterm labor

A patient, while on intravenous ritodrine therapy for preterm labor, experienced an episode of acute chest pain. The electrocardiogram (ECG), which was read as normal prior to ritodrine infusion, demonstrated a type I second-degree AV block which disappeared upon discontinuation of ritodrine therapy. This case illustrates the need for close ECG monitoring during ritodrine treatment when clinical symptoms arise.     

Failed induction of labor despite sequential prostaglandin E2 therapy

Preinduction cervical ripening with prostaglandin E2 (PGE2) is useful in minimizing the chances for a failed induction of labor. The lack of sufficient cervical dilation despite PGE2 and oxytocin therapy is uncommon. This investigation was undertaken to determine reasons for any failed inductions in pregnancies with pregel Bishop scores 4 or lower and requiring delivery within 24 hours. Fifteen (12.1%) of 124 eligible patients had failed inductions despite two 2.5 mg intravaginal doses. A finding in all the failures was a very unfavorable cervix (pregel Bishop score 0 to 2). The need for preterm delivery (33 to 37 weeks) was a common finding in the presence of a very unfavorable cervix. The data suggest that complicated pregnancies requiring delivery within 24 hours and failing to respond to sequential PGE2 therapy in the presence of a very unfavorable cervix may benefit from cesarean section without a prolonged induction.     

Responsibility for HIV prevention: patterns of attribution among HIV-seropositive gay and bisexual men.

The Seroconversion Narratives for AIDS Prevention (SNAP) study elicited narratives from recently infected seropositive gay and bisexual men that described the circumstances of their own seroconversion. This analysis of the narratives explored participants' attributions of responsibility for HIV prevention before and after they became infected. Before becoming infected with HIV, responsibility for prevention was often attributed to HIV-negative individuals themselves. These retrospective attributions revealed themes that included feelings of negligence, a sense of consequences, followed by regret. After seroconversion, responsibility for HIV prevention was primarily attributed to HIV-positive individuals themselves. Themes within these attributions included pledges to avoid HIV transmission, a strong sense of burden related to the possibility of infecting someone, and risk reduction strategies that they implemented in an attempt to avoid HIV transmission. Greater understanding of ideas related to responsibility has the potential to increase the effectiveness of HIV prevention interventions.     

Comparison of the Gen-Probe PACE 2 system, direct fluorescent-antibody, and cell culture for detecting Chlamydia trachomatis in cervical specimens

A chemiluminescent-labeled DNA probe (Gen-Probe PACE 2 System) for detection of Chlamydia trachomatis in endocervical specimens was evaluated. For each specimen, tissue cell culture, direct immunofluorescent staining (DFA), and DNA probe assay were performed. Thirty of 318 (9.4%) specimens were positive for C. trachomatis. The sensitivities, specificities, and positive and negative predictive values of the DNA probe compared with cell culture were 93%, 98%, 85%, and 99%, respectively, and for DFA these same values were 81%, 99%, 83%, and 99%, respectively. The Gen-Probe PACE 2 System is a reliable method for the rapid detection of endocervical chlamydial infection.     

In vitro and in vivo activities of WIN 54954, a new broad-spectrum antipicornavirus drug

WIN 54954 (5-[5-[2,6-dichloro-4-(4,5-dihydro-2-oxazolyl)phenoxy]pentyl]-3- methylisoxazole) is a new member of the class of broad-spectrum antipicornavirus compounds known to bind in a hydrophobic pocket within virion capsid protein VP1. In plaque reduction assays, WIN 54954 reduced plaque formation of 50 of 52 rhinovirus serotypes (MICs ranged from 0.007 to 2.2 micrograms/ml). A concentration of 0.28 microgram/ml was effective in inhibiting 80% of the 52 serotypes tested (EC80). WIN 54954 was also effective in inhibiting 15 commonly isolated enteroviruses, with an EC80 of 0.06 microgram/ml. Furthermore, WIN 54954 was effective in reducing the yield of two selected enteroviruses in cell culture by 90% at concentrations approximately equal to their MICs. The therapeutic efficacy of intragastrically administered WIN 54954 was assessed in suckling mice infected with coxsackievirus A-9 or echovirus type 9 (Barty) 2.5 days prior to initiation of therapy. Single daily doses of 2 and 100 mg/kg protected 50% of the mice from developing paralysis (PD50) following infection with coxsackievirus A-9 and echovirus-9, respectively. At the PD50 doses for these two viruses, levels of WIN 54954 in serum were maintained above the in vitro MICs for a significant portion of the dosing interval. The dose-dependent reduction in viral titers observed in coxsackievirus A-9-infected mice correlated well with the therapeutic dose response. The potency and spectrum of WIN 54954 make it a potentially useful compound for the treatment of human enterovirus and rhinovirus infections.     

Isolated colonic hemangioma in a child.

Hemangiomas of the large bowel are very rare and usually occur in the rectosigmoid. A large cavernous hemangioma of the colon was demonstrated in a 9-month-old child who presented with recurrent lower gastrointestinal tract bleeding. Barium examination demonstrated an annular lesion of the hepatic flexure. Computed tomography demonstrated the extent of the lesion, and contrast enhancement suggested the vascular nature of the tumour before a laparotomy was performed to remove the tumour.     

Mean diffusivity: A biomarker for CSF-related disease and genetic liability effects in schizophrenia

Mean diffusivity (MD), the rotationally invariant magnitude of water diffusion that is greater in cerebrospinal fluid (CSF) and smaller in organized brain tissue, has been suggested to reflect schizophrenia-associated cortical atrophy. Regional changes, associations with CSF, and the effects of genetic predisposition towards schizophrenia, however, remain uncertain. Six-direction diffusion tensor imaging DTI and high-resolution structural images were obtained from 26 schizophrenia patients, 36 unaffected first-degree patient relatives, 20 control subjects and 32 control relatives (N = 114). Registration procedures aligned diffusion tensor imaging (DTI) data across imaging modalities. MD was averaged within lobar regions and the cingulate and superior temporal gyri. CSF volume and MD were highly correlated. Significant bilateral temporal, and superior temporal MD increases were observed in schizophrenia compared with unrelated control probands. First-degree relatives of schizophrenia probands showed larger MD measures compared with controls within bilateral superior temporal regions with CSF volume correction. Superior temporal lobe brain tissue deficits and proximal CSF enlargements are widely documented in schizophrenia. Larger MD indices in patients and their relatives may thus reflect similar pathophysiological mechanisms. However, persistence of regional MD effects after controlling for CSF volume, suggests that MD is a sensitive biological marker of disease and genetic liability, characterizing at least partially distinct aspects of brain structural integrity.     

19F MR imaging of ventilation and diffusion in excised lungs.

Perfluorinated gases, particularly C2F6, are potentially suitable alternatives to hyperpolarized noble gases for pulmonary airspace spin density and diffusion MRI. This work focuses mainly on 19F imaging of C2F6 gas in healthy and emphysematous explanted lungs, avoiding regulatory issues of human in vivo measurements. Three-dimensional gradient echo and spin echo spin density images of human lungs can be made in 10 s with adequate signal-to-noise, demonstrating the feasibility for breathing dynamics to be captured during a succession of short breath holds. As expected, the spin echo images have much smaller susceptibility artifacts than the gradient echo images. 19F and 3He images of the same lungs are compared. The apparent diffusion coefficient (ADC) of C2F6 is sensitive to restrictions imposed by the lung microstructure: the average ADC is measured to be 0.018 cm2/s in healthy lungs versus 0.031 cm2/s in emphysematous lungs at a diffusion time Delta=2.2 ms. The low free diffusivity of pure C2F6 (D0=0.033 cm2/s) places it in a regime where the ADC measurement allows the surface-to-volume ratio to be determined in each voxel, a potentially valuable quantitative characterization of regional lung tissue destruction in emphysema.     

Mycobacterial testing in clinical laboratories that participate in the College of American Pathologists' Mycobacteriology E survey: results of a 1993 questionnaire.

Participants in the College of American Pathologists' Mycobacteriology E proficiency testing survey in 1993 were asked to complete a questionnaire addressing mycobacterial test methods, test volume, and frequency of detection of drug-resistant Mycobacterium tuberculosis (MTB). A similar questionnaire had been distributed in 1992. The population responding to the 1993 questionnaire changed, because of a shift of small hospitals to the limited Mycobacteriology E1 survey, and the format of some questions was altered, so a direct comparison of 1992 and 1993 responses was not always possible. Among participants who answered the questions in both years, there was a significant increase in the use of the fluorochrome stain (57% in 1992, 61% in 1993), BACTEC TB for culture (34% in 1992, 38% in 1993) and susceptibility testing (51% in 1992, 61% in 1993), and DNA probes for identification (30% in 1992, 51% in 1993). The percentage of participants who processed respiratory specimens at least seven times per week increased from 9% in 1992 to 13% in 1993, and the percentage processing five times per week increased from 68 to 72%. The percentage of respondents who reported an identification of MTB within 21 days of specimen receipts and susceptibility test results within 28 days in 1992 and 1993 increased from 30 to 41% and from 12 to 19%, respectively. In regard to resistant MTB, 177 institutions in 1991 and 291 in 1992 reported resistance to isoniazid, and 114 in 1991 and 187 in 1992 reported resistance to both isoniazid and rifampin. Laboratorians are to be applauded for using the more rapid mycobacterial testing methods; however, given that tuberculosis remains a problem, this trend must continue.