Recent Publications by CFE Educators

Acute basilar artery occlusion has a mortality rate approaching 90%. The authors describe a case of acute basilar artery occlusion managed successfully with endovascular embolectomy. A 31-year-old man sought treatment for confusion, dysarthria, and right-sided weakness. He soon became unresponsive and was found to have a vertebral artery dissection and an associated basilar artery embolism. The dissection was managed with endovascular stenting, and the basilar artery embolus was removed with a clot retriever at 7 hours. The patient recovered without neurologic deficit.

BACKGROUND AND PURPOSE

Current guidelines recommend the use of head CT in the evaluation of patients with transient ischemic attack (TIA), but data supporting its value are sparse.

METHODS

Patients who presented to 1 of 16 emergency departments of a large Northern California health maintenance organization and received a diagnosis of TIA from November 1997 through February 1998 were enrolled and followed up for 90 days. Clinical, demographic, and outcome data were obtained from computerized databases and medical records. Physicians blinded to patient characteristics and outcomes abstracted head CT findings from radiology reports. Abstracted findings included evidence of old or new infarct, periventricular white-matter disease, cerebral atrophy, cerebral vascular calcification, and nonischemic lesions.

RESULTS

Head CT was performed in 67% of eligible patients (n=322) diagnosed with TIA. Evidence of a new infarct was seen on head CT in 13 patients (4%). A nonischemic cause of TIA symptoms was found in 4 patients (1.2%). During follow-up, 10.9% of TIA patients experienced subsequent stroke. After adjustment for confounders, risk for stroke during follow-up was significantly higher in those with a new infarct on head CT compared with others with TIA (odds ratio, 4.06; 95% confidence interval, 1.16 to 14.14; P=0.028). Old infarction, periventricular white-matter disease, cerebral atrophy, and cerebral vascular calcification were not predictors of subsequent risk of stroke.

CONCLUSIONS

Evidence of a new infarct on head CT in patients presenting with TIA is associated with increased short-term risk for stroke. Head CT appears to have prognostic value in patients with TIA and, for this reason alone, may be justified in their evaluation.

Streptococcus pneumoniae normally resides in the human nasopharynx in a nondisease state. In response to unknown triggers this organism can descend to the lower respiratory tract and/or invade the bloodstream. Regulation and activation of virulence genes play essential roles in this process of disease development. Characterization of S. pneumoniae regulatory networks has been a recent area of interest, but despite inroads little is known about regulation of virulence genes in this pathogen. A putative transcriptional regulator in S. pneumoniae, mgrA, which exhibits homology to the virulence gene activator mga of group A streptococcus, was previously identified as a regulator that is required for development of pneumonia in a murine model. In this study we confirmed that mgrA plays a role in both nasopharyngeal carriage and pneumonia. Transcriptional profiling by microarray technology was used to show that mgrA acts as a repressor of the previously characterized rlrA pathogenicity islet. This is manifested phenotypically by a decrease in adherence to epithelial cells in tissue culture since the rlrA pathogenicity islet contains genes mediating adherence.

Homologues of the protein constituents of the Klebsiella pneumoniae (Klebsiella oxytoca) type II secreton (T2S), the Pseudomonas aeruginosa type IV pilus/fimbrium biogenesis machinery (T4P) and the Methanococcus voltae flagellum biogenesis machinery (Fla) have been identified. Known constituents of these systems include (1). a major prepilin (preflagellin), (2). several minor prepilins (preflagellins), (3). a prepilin (preflagellin) peptidase/methylase, (4). an ATPase, (5). a multispanning transmembrane (TM) protein, (6). an outer-membrane secretin (lacking in Fla) and (7). several functionally uncharacterized envelope proteins. Sequence and phylogenetic analyses led to the conclusion that, although many of the protein constituents are probably homologous, extensive sequence divergence during evolution clouds this homology so that a common ancestry can be established for all three types of systems for only two constituents, the ATPase and the TM protein. Sequence divergence of the individual T2S constituents has occurred at characteristic rates, apparently without shuffling of constituents between systems. The same is probably also true for the T4P and Fla systems. The family of ATPases is much larger than the family of TM proteins, and many ATPase homologues function in capacities unrelated to those considered here. Many phylogenetic clusters of the ATPases probably exhibit uniform function. Some of these have a corresponding TM protein homologue although others probably function without one. It is further shown that proteins that compose the different phylogenetic clusters in both the ATPase and the TM protein families exhibit unique structural characteristics that are of probable functional significance. The TM proteins are shown to have arisen by at least two dissimilar intragenic duplication events, one in the bacterial kingdom and one in the archaeal kingdom. The archaeal TM proteins are twice as large as the bacterial TM proteins, suggesting an oligomeric structure for the latter.

CONTEXT

Although studies have examined U.S. pill users' patterns of discontinuation, little is known about pill discontinuation, and the effects of partner influence, among Hispanics.

METHODS

Follow-up data on pill use were collected from 213 predominantly Hispanic women who requested the pill in an urban family planning clinic in 2000. Logistic regression analyses were conducted to assess the association between a range of factors, including partner and relationship variables, and the odds of discontinuation within one month.

RESULTS

The overall discontinuation rate within one month was 23%. Women who reported that their partner was unaware of their planned pill use had significantly elevated odds of discontinuing use (odds ratio, 3.4). Other variables that were independently associated with increased odds of early pill discontinuation were not taking the first pill during the clinic visit (3.0), feeling happy about the prospect of a pregnancy in the next six months (2.4) and intending to use the pill for one year or less (2.3). Age, which was assessed as a continuous variable, was negatively associated with the odds of early discontinuation (0.9).

CONCLUSIONS

Male partners' awareness of planned pill use may be a marker for the level of communication and commitment in the relationship. Women may choose to disclose their planned pill use to supportive partners, and this may be beneficial to the relationship and the couple's contraceptive use. However, clinicians should take women's circumstances and needs into account before counseling them to tell a partner that they intend to use the pill.

Coronary microvascular damage can occur in the presence of myocardial ischemia even if epicardial vessels are patent, a phenomenon known as "no-reflow." Estrogens have favorable effects on coronary conductance and resistance arteries, and may have therapeutic value in ischemic syndromes. Myocardial contrast echocardiography (MCE) is a promising method for evaluating microvascular damage. In this study, the authors hypothesized that acute intracoronary 17beta-estradiol administration can reduce postischemic microvascular damage, which is evaluated by MCE, in a porcine model. Sixteen male pigs were randomized into 2 groups: the treatment group (n = 9) received intracoronary estradiol in increasing doses, and the control group (n = 7) received intracoronary vehicle (dimethylsulfoxide, DMSO). Microvascular damage was induced by balloon catheter occlusion followed by reperfusion of the left circumflex coronary artery (LCX). MCE using Levovist with harmonic imaging was performed before and during 15-minute balloon occlusion of the proximal LCX to determine perfusion areas of the left anterior descending artery (LAD) and LCX. MCE was performed immediately postocclusion and after each injection of estradiol (1, 10, and 100 nmol/L) or DMSO. Videodensitometry measurements were performed as a quantitative marker for myocardial microvascular damage. Videodensitometry results were expressed as peak intensity ratios. Intracoronary estradiol induced a significant reduction in myocardial microvascular damage after ischemic episode by videodensitometry measurements when compared to intracoronary DMSO. The authors conclude that intracoronary injection of estradiol reduces postischemic microvascular damage measured by MCE in a porcine model.

OBJECTIVE

The purpose of this study was to determine whether rates of hypertensive disorders of pregnancy increase beyond 37 weeks of gestation and to address how best to analyze these rates.

STUDY DESIGN

This was a retrospective cohort study of all women delivered beyond 37 weeks' gestational age from 1995 to 1999 at all Kaiser Permanente Medical Care Program delivery hospitals in Northern California. Rates of gestational hypertension, preeclampsia, and eclampsia were calculated by use of both pregnancy delivered (PD) and ongoing pregnancy (OP) as the denominator. Bivariate and multivariate analyses were conducted with use of P.05 to indicate statistical significance.

RESULTS

Among the 135,560 women in this cohort, the rates of gestational hypertension, preeclampsia, and eclampsia were the same or decreased from 37 to 43 weeks' gestation using PD, but all three increased when calculated according to OP (P.01).

CONCLUSION

We found that among complications of pregnancy that are diagnosed ante partum, use of a different denominator led to contradictory conclusions. When hypertensive disorders of pregnancy are analyzed, ongoing pregnancies should be used as the denominator.

Mouse genetics has contributed significantly to our understanding of molecular mechanisms underlying tissue and nerve injury-induced persistent pain. To create a highly reproducible, relatively noninvasive model of neuropathic pain in the mouse, we examined the behavioral consequences of sparing each of the 3 distal branches of the sciatic nerve in wild-type mice after a model originally described in the rat. Sparing the tibial branch but sparing neither of the other branches produced robust mechanical allodynia while leaving heat sensibility intact. To assess the topographic organization of the IB4 population of afferents from each branch and to compare anatomic consistency across injury models, we examined loss of thiamine monophosphatase staining in the superficial dorsal horn after peripheral nerve injury. We found that each of the sciatic branches targets a distinct mediolateral location in inner lamina II and that each of the spared nerve injury models produced a more reproducible pattern of thiamine monophosphatase staining loss than did partial tight ligation. These results improve on previous nerve injury models in mouse, demonstrate similar behavioral changes as in rat, and provide novel information on the topographic organization of small diameter peripheral afferents in the mouse spinal cord.