Validation of a technique using microbubbles and contrast enhanced ultrasound (CEUS) to biopsy sentinel lymph nodes (SLN) in pre-operative breast cancer patients with a normal grey-scale axillary ultrasound

BACKGROUND

In patients with breast cancer, grey-scale ultrasound often fails to identify lymph node (LN) metastases. We aimed to validate the technique of contrast-enhanced ultrasound (CEUS) as a test to identify sentinel lymph node (SLN) metastases and reduce the numbers of patients requiring a completion axillary node clearance (ANC).

METHODS

371 patients with breast cancer and a normal axillary ultrasound were recruited. Patients received periareolar intra-dermal injection of microbubble contrast agent. Breast lymphatics were visualised by CEUS and followed to identify and biopsy axillary SLN. Patients then underwent standard tumour excision and either SLN excision (benign biopsy) or axillary clearance (malignant biopsy) with subsequent histopathological analysis.

RESULTS

The technique failed in 46 patients, 6 patients had indeterminate biopsy results and 24 patients were excluded. In 295 patients with a conclusive SLN biopsy, the sensitivity of the technique was 61% and specificity 100%. Given a benign SLN biopsy result, the post-test probability that a patient had SLN metastases was 8%. 35 patients were found to have SLN metastases and had a primary ANC (29 macrometastases and 6 micrometastases/ITC). There were 22 false negative results (10 macrometastases and 12 micrometastases). Macrometastases in core biopsy specimens correlated with LN macrometastases on surgical excision.

CONCLUSION

Pre-operative biopsy of SLN reduced the numbers of patients requiring completion ANC. Despite the low sensitivity, only 22 patients (8%) with a benign SLN biopsy were subsequently found to have LN metastases. Without the confirmation of macrometastases on core biopsy specimens, patients with micrometastases/ITC may be inadvertently selected for primary ANC.

Frequency of electrocardiogram testing among HIV-infected patients at risk for medication-induced QTc prolongation

OBJECTIVES

HIV-infected patients are commonly prescribed several medications and are thus at risk for drug interactions that may result in QTc prolongation. We sought (1) to identify the frequency of electrocardiogram (ECG) monitoring (2), to determine the prevalence of drug interactions involving QTc-prolonging medications, and (3) to quantify the prevalence of QTc prolongation.

METHODS

A cross-sectional study was conducted among HIV-infected adults. Demographics, medications, drug interactions and comorbidities were abstracted from patients' medical records. Abnormal QTc interval was defined per the UK Committee for Proprietary Medicinal Products. Clinical characteristics were compared among ECG recipients and nonrecipients. Among ECG recipients, the prevalence and predictors of QTc prolongation were assessed.

RESULTS

Among the 454 patients included in the study, 80.8% were prescribed a medication associated with QTc prolongation and 39% had drug interactions expected to increase QTc prolongation risk. There were 138 patients (30.3%) who received ECG testing. Receipt of ECG monitoring was associated with increasing age, diabetes, increasing total number of medications and gastroesophageal reflux disease. Among ECG recipients, the prevalence of abnormal QTc interval was 27.5%. Chronic kidney disease [prevalence ratio (PR) 3.47; 95% confidence interval (CI) 1.37-8.83; P = 0.009], hepatitis C virus coinfection (PR 2.26; 95% CI 0.97-5.27; P = 0.06) and hypertension (PR 2.11; 95% CI 0.93-4.81; P = 0.07) were independently associated with an abnormal QTc interval.

CONCLUSIONS

A low frequency of ECG testing was observed, despite a high use of medications associated with QTc prolongation. The risk of abnormal QTc interval was highest among patients with chronic kidney disease, hypertension and hepatitis C virus coinfection.

A novel approach to identify sentinel lymph nodes using microbubbles and contrast enhanced ultrasound in preoperative breast cancer patients

e11543

Background: In patients with early invasive breast cancer, surgical excision of sentinel lymph nodes (SLN) has been shown to be a safe and accurate first-line technique to stage the axilla. In animal models, superficial lymphatics can be imaged using ultrasound and intradermal microbubbles. We investigated the ability of contrast enhanced ultrasound to identify SLN preoperatively in breast cancer patients. Methods: We recruited 46 consecutive consenting patients with primary breast cancer. Pre-operatively; patients received periareolar intra-dermal injection of microbubble contrast agent, breast lymphatics were visualised by ultrasound and followed to identify putative axillary SLN. In 41 patients, we aimed to place guide-wires in the SLN. Patients then underwent standard operative tumour excision, SLN biopsy and histopathological analysis. Results: Microbubble enhancement identified putative SLN in 5 successive patients. In 36 patients, putative SLN were visualised and guide-wires deployed. Operative findings confirmed the wired lymph nodes (LN) were SLN. In 2 cases, SLN contrast enhancement failed but guide-wires were placed into prominent grey-scale imaged LN. These wired LN were not SLN. In 3 patients, the procedure failed. Contrast enhanced ultrasound correctly identified SLN in 36 of 41 patients (88%). Five patients were found to have metastasis. In all metastatic cases, SLN were correctly identified and localised with guide-wires pre-operatively. Conclusions: Microbubbles readily enter breast lymphatics and contrast enhanced ultrasound may represent a practical method to identify SLN. Improvements in percutaneous techniques may facilitate ultrasound guided SLN excision in the breast clinic and could reduce the numbers of patients requiring axillary surgery.

No significant financial relationships to disclose.

Scar formation after stereotactic vacuum-assisted core biopsy of benign breast lesions

AIM

To evaluate scar formation of impalpable breast lesions with benign histological outcome using stereotactic 11-gauge vacuum-assisted core biopsy (VACB).

MATERIALS AND METHODS

Two hundred and ten lesions with benign histology for which follow-up mammograms were available, were assessed for scar formation at the biopsy site. All biopsies were performed using stereotactic VACB with 11-gauge needle. The incidence of post-biopsy scar formation and the number of specimens removed were determined.

RESULTS

In 4.3% (9/210) of the lesions for which a biopsy was performed with 11-gauge directional vacuum-assisted technique, the follow-up mammogram revealed a scar formation. Of these, six were minimal scars, two were moderate scars and one was a marked scar. Minimal and moderate scars were diagnosed on imaging only. However, the case with marked scar formation required tissue diagnosis to rule out malignancy.

CONCLUSION

Although uncommon, scar formation can be seen in the follow-up mammograms after percutaneous breast biopsies. It is important that the radiologist interpreting follow-up mammograms is aware of the features of this lesion and its relationship to the biopsy procedure.

Effect of a closed drug-delivery system on the incidence of nosocomial and catheter-related bloodstream infections in infants

We conducted a prospective, cohort study at two affiliated level III neonatal intensive care units to evaluate the effect of a closed drug-delivery system on the incidence of nosocomial and catheter-related bloodstream infections (CRBSI) in infants. A total of 300 infants (n=150 at each site) were enrolled over a 4-year study period. There was no difference in the rate of CRBSI per 1000 catheter days between the two sites (16.2+/-39 vs. 8.9+/-24, P=0.054, 95% CI-14.8 to 0.13). Infants at site A (closed drug-delivery system) had a higher rate of infectious nosocomial respiratory complications per 100 hospital days than infants at site B (open delivery system) (1.1+/-2.2 vs. 0.5+/-1.5, P=0.009), however, there was no difference in the overall number of confirmed or suspected nosocomial infection events per patient between study sites. Logistic regression revealed that the number of additional peripheral catheters, gestational age and duration of parenteral nutrition all significantly contributed to the risk of developing one or more CRSBI. The closed drug-delivery system failed to reduce the incidence of CRBSI or overall rate of nosocomial infections in premature infants.

Spatiotemporal patterns of host-seeking Ixodes scapularis nymphs (Acari: Ixodidae) in the United States

The risk of Lyme disease for humans in the eastern United States is dependent on the density of host-seeking Ixodes scapularis Say nymphal stage ticks infected with Borrelia burgdorferi. Although many local and regional studies have estimated Lyme disease risk using these parameters, this is the first large-scale study using a standardized methodology. Density of host-seeking I. scapularis nymphs was measured by drag sampling of closed canopy deciduous forest habitats in 95 locations spaced among 2 degrees quadrants covering the entire United States east of the 100th meridian. Sampling was done in five standardized transects at each site and repeated three to six times during the summer of 2004. The total number of adults and nymphs of the seven tick species collected was 17,972, with 1,405 nymphal I. scapularis collected in 31 of the 95 sites. Peak global spatial autocorrelation values were found at the smallest lag distance (300 km) and decreased significantly after 1,000 km. Local auto-correlation statistics identified two significant high-density clusters around endemic areas in the northeast and upper Midwest and a low-density cluster in sites south of the 39th parallel, where only 21 nymphs were collected. Peak nymphal host-seeking density occurred earlier in the southern than in the most northern sites. Spatiotemporal density patterns will be combined with Borrelia prevalence data as part of a 4-yr survey to generate a nationwide spatial risk model for I. scapularis-borne Borrelia, which will improve targeting of disease prevention efforts.

Maintaining high autopsy rates in a Canadian blood and marrow transplant program: preserving a diagnostic and research tool

Autopsy series have revealed patterns of injury in graft-versus-host disease and provided insight into infectious and toxic complications following hematopoietic stem cell transplantation (HSCT). Overall autopsy rates have declined significantly in recent decades including specialized services such as neonatal medicine and cardiac care. However, rates of post-mortem exams at HSCT centers have not been specifically documented. We reviewed hospital records between 1992 and 2002 to determine overall autopsy rates at our hospital and within the HSCT program. Although the overall autopsy rate declined steadily from 24% in 1992 to 9% in 2002, rates of post-mortem exams in the HSCT program remained relatively stable at 32% (24-46%). Autopsy rates were not significantly different for recipients of allogeneic vs autologous transplants and no clear difference was observed for the proportion of autopsies requested on weekdays compared with weekends. Autopsies confirmed major clinical diagnoses and/or suspected causes of death in 45 of 61 autopsies (74%) and yielded major or minor disagreements in clinical diagnosis in 10 cases (16%) and seven cases (11%), respectively. The preservation of high rates of autopsy within our HSCT program demonstrates that specialized programs are able to maintain elevated rates of post-mortem examinations despite overall declining rates.

Topotecan in the treatment of acquired immunodeficiency syndrome-related progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) affects about 1 in 20 individuals with the acquired immunodeficiency syndrome (AIDS) and has been associated with poor survival. This report describes the results of a phase II clinical trial using the drug topotecan, a semisynthetic analogue of camptothecan, administered to a cohort of subjects with AIDS-related PML. Data were evaluated on 11 of 12 subjects enrolled in the study. Three responded to therapy. Additionally, one patient was treated off-protocol and showed a response to treatment. Progression occurred after the first course; however, a partial response was noted after five courses. One study patient died from accidental overdose of topotecan. Overall, responders had higher pretreatment Karnofsky and lower Kurtzke expanded disability status scale scores than nonresponders. The most frequent toxicities were hematologic (anemia, neutropenia, and thrombocytopenia). Five patients had dose delays; all delays were due to hematologic adverse events. This study demonstrates that topotecan treatment may be associated with decreased lesion size and prolonged survival from the infection. Because of the small number of subjects in the study, further studies are required to evaluate the efficacy of topotecan in treating this disease.

Interference between the agents of Lyme disease and human granulocytic ehrlichiosis in a natural reservoir host

Agents of Lyme disease (Borrelia burgdorferi) and human granulocytic ehrlichiosis (Ehrlichia phagocytophila) are perpetuated in a natural cycle involving the black-legged tick (Ixodes scapularis) and its vertebrate hosts. Using I. scapularis nymphs as the mode of infectious challenge, we studied how infection with one pathogen in white-footed mice (Peromyscus leucopus) affects their ability to acquire the other agent and subsequently to infect larvae, which these agents would do in nature. Two groups of mice were infected with either B. burgdorferi or E. phagocytophila. One week later, B. burgdorferi-infected mice were challenged with E. phagocytophila, and E. phagocytophila-infected mice were challenged with B. burgdorferi. Simultaneously, two control groups of uninfected mice were infected with each agent from the same tick cohorts used on the first groups of mice. Uninfected I. scapularis larvae were fed on all mice for xenodiagnosis at weekly intervals lasting 2 months. For the B. burgdorferi challenge, all control and E. phagocytophila-infected mice acquired B. burgdorferi. However, fewer xenodiagnostic larvae acquired B. burgdorferi from mice with mixed infections compared with mice infected with B. burgdorferi only. For the E. phagocytophila challenge, all five control mice acquired E. phagocytophila, but only two of five mice infected with B. burgdorferi subsequently acquired E. phagocytophila. Consequently, mice with both infections produced fewer xenodiagnostic ticks infected with E. phagocytophila than mice infected with E. phagocytophila only. Thus, a primary infection with either B. burgdorferi or E. phagocytophila in mice inhibited transmission of a second agent, suggesting interference between these two agents.

A relapsing fever group spirochete transmitted by Ixodes scapularis ticks

A species of Borrelia spirochetes previously unknown from North America has been found to be transmitted by Ixodes scapularis ticks. Infected ticks are positive for Borrelia spp. by DFA test but negative for Borrelia burgdorferi by polymerase chain reaction (PCR) using species-specific primers for 16S rDNA, outer surface protein A, outer surface protein C, and flagellin genes. A 1,347-bp portion of 16S rDNA was amplified from a pool of infected nymphs, sequenced, and compared with the homologous fragment from 26 other species of Borrelia. The analysis showed 4.6% pairwise difference from B. burgdorferi, with the closest relative being Borrelia miyamotoi (99.3% similarity) reported from Ixodes persulcatus in Japan. Phylogenetic analysis showed the unknown Borrelia to cluster with relapsing fever group spirochetes rather than with Lyme disease spirochetes. A 764-bp fragment of the flagellin gene was also compared with the homologous fragment from 24 other Borrelia species. The flagellin sequence of B. burgdorferi was 19.5% different from the unknown Borrelia and showed 98.6% similarity with B. miyamotoi. A pair of PCR primers specifically designed to amplify a 219-bp fragment of the flagellin gene from this spirochete was used to survey field-collected I. scapularis nymphs from five northeastern states (Connecticut, Rhode Island, New York, New Jersey, and Maryland). Positive results were obtained in 1.9-2.5% of 712 nymphs sampled from four states but in none of 162 ticks collected from Maryland. Transovarial transmission was demonstrated by PCR of larval progeny from infected females with filial infection rates ranging from 6% to 73%. Transstadial passage occurred from larvae through adults. Vertebrate infection was demonstrated by feeding infected nymphs on Peromyscus leucopus mice and recovering the organism from uninfected xenodiagnostic larvae fed 7-21 days later. Considering the frequency of contact between I. scapularis and humans, further work is needed to determine the potential public health significance of yet another zoonotic agent transmitted by this tick species.

OspA immunization decreases transmission of Borrelia burgdorferi spirochetes from infected Peromyscus leucopus mice to larval Ixodes scapularis ticks

Recombinant outer surface protein A (OspA) vaccination of wild animal reservoirs has potential application for reducing Borrelia burgdorferi transmission in nature and subsequent risk of human infection. As a major reservoir host, the white-footed mouse (Peromyscus leucopus) is a candidate for a vaccination program designed to reduce infection prevalence in vector ticks. In this study we characterized the effect of various levels of immunization with recombinant OspA-glutathione transferase fusion protein on transmission dynamics from infected P. leucopus to larval ticks. Control mice were vaccinated with glutathione transferase alone. All mice were experimentally infected with B. burgdorferi before vaccination. The immune responses of the immunized mice were assessed by enzyme-linked immunosorbent assay for antibodies to OspA. Transmission of B. burgdorferi from infected mice was determined by xenodiagnosis with uninfected larval ticks. Spirochetes in ticks were counted by direct immunofluorescence assay. The concentration of antibody to OspA increased with each OspA vaccination but most markedly after the first and second vaccinations. In comparison with control mice, there was reduced transmission by OspA-vaccinated mice to uninfected ticks. One, two, or three doses of OspA reduced infection prevalence in xenodiagnostic ticks by 48%, 92%, or 99% and the numbers of spirochetes per tick by 84%, 98%, or 99%, respectively. This study suggests that vaccination of P. leucopus with OspA could reduce transmission to the tick vector in nature despite prior infection of the reservoir host.

Possible interaction between intravenous azithromycin and oral cyclosporine

A 42-year-old man who had received a cadaveric kidney transplant 9 years earlier was admitted to the hospital with pneumonia. His oral cyclosporine dosage for the past 2 years was stabilized at 100 mg twice/day; his cyclosporine whole blood trough levels 15 days earlier and on the day he was admitted were both 178 ng/ml. The patient was treated with intravenous ceftriaxone and intravenous azithromycin and continued to receive the same dosage of oral cyclosporine. On hospital day 3, his cyclosporine trough level rose to 400 ng/ml and his dosage was reduced by 50%. Trough levels were 181 ng/ml and 175 ng/ml on hospital days 6 and 9, respectively On hospital day 9, the patient stopped receiving azithromycin. On hospital day 14, his cyclosporine trough level dropped to 76 ng/ml, and his cyclosporine dosage was increased back to 100 mg twice/day. The dosage produced trough levels consistent with those before he had been admitted. The patient was discharged on day 20, and a follow-up cyclosporine trough level determined 3 weeks later was 175 ng/ml. Administration of azithromycin may have caused the increased cyclosporine concentrations in this patient through p-glycoprotein inhibition and/or competition for biliary excretion. Azithromycin's interference may be inferred by the increase in cyclosporine levels after administration of this drug and the decrease in cyclosporine levels after its discontinuation-both consistent with the pharmacokinetic properties of cyclosporine. Ceftriaxone and acute-phase reactant activation during infection, however, also may have interfered with the patient's cyclosporine elimination. Azithromycin generally is considered unlikely to interact with cyclosporine. Nonetheless, practitioners should be aware of this possibility and should monitor cyclosporine levels closely, especially in critically ill patients who have other complications.

Return to work: conducting a worksite assessment

George is a 46 year old who, at work, develops back pain with right sided sciatica. Initial findings include an absent right ankle jerk with sensory loss in the distribution of the right S1 nerve root. MRI scan confirms the diagnosis of an L5-S1 disc herniation with pressure on the right S1 nerve root. Following referral to a neurosurgeon he undergoes microdiscectomy. He is now six weeks postoperative. The scar healed well. His sciatica and ankle jerk have improved. He is now considering returning to work.

Allogeneic transplantation for multiple myeloma: further evidence for a GVHD-associated graft-versus-myeloma effect

We report a series of 37 consecutive patients with multiple myeloma (MM) who received an allograft between 1990 and 2000 at our institution. Median age was 47 years, and nearly 70% of patients were Durie-Salmon stage III. A median of five cycles of chemotherapy were given before transplant, with a median interval between diagnosis and transplant of 9.3 months. We report a nonrelapse mortality rate of 22% with a median follow-up period of 40 months, whereas complete remission (CR) rate at 12 months is estimated at 57%. Treatment failure rate and overall survival at 40 months are estimated at 52% and 32%, respectively. The number of chemotherapy cycles prior to allotransplantation achieved borderline statistical significance as a poor prognosis factor for overall survival (P = 0.05), while the presence of chronic graft-versus-host disease (cGVHD) was significantly correlated with CR achievement (P = 0.036). Our study confirms that early allografting in MM can yield toxicity rates significantly lower than those associated with historical cohorts, and supports the hypothesis that cumulative chemotoxicity has a negative influence on mortality and survival rates. More importantly, our study clearly demonstrates an association between cGVHD and CR and brings further evidence in favor of a graft-versus-myeloma effect.

Subcellular localisation of the X protein in HBV infected hepatocytes

Hepatitis B virus X protein (HBx) is a multifunctional protein that exerts its effects primarily by acting as a transcriptional transactivator of viral and multiple host cell genes. HBx is thought to be essential for maintaining viral replication and has been implicated in the development of hepatocellular carcinoma in patients chronically infected with hepatitis B virus. Very little is known about its functional mechanisms and although interactions with several nuclear and cytoplasmic proteins have been demonstrated in vitro, there is no clear consensus as to where HBx localises in infected hepatocytes. In this study, the expression and intracellular distribution of HBx were examined in human liver biopsies using an anti-HBx rabbit polyclonal antiserum. HBx was detected in a high proportion (69%) of samples from patients with chronic HBV infection. Detection of HBx correlated with the absence of cirrhosis and the presence of serum e-antigen. HBx was detected predominantly in the cytoplasm; however, it was also found in the nuclei of up to 20% of positively stained hepatocytes, either exclusively nuclear or localised both in the nucleus and cytoplasm within the same cell. Furthermore, the intracellular distribution of HBx was analysed in transfected Huh-7 cells by confocal microscopy, using the monoclonal antibody 16F1. In these experiments, a substantial nuclear detection was confirmed in a significant proportion of HBx expressing cells. The data indicate a high functional significance of nuclear HBx, consistent with the concept that transactivation may involve interactions with nuclear proteins.

Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite

BACKGROUND

It is unclear whether antimicrobial treatment after an Ixodes scapularis tick bite will prevent Lyme disease.

METHODS

In an area of New York where Lyme disease is hyperendemic we conducted a randomized, double-blind, placebo-controlled trial of treatment with a single 200-mg dose of doxycycline in 482 subjects who had removed attached I. scapularis ticks from their bodies within the previous 72 hours. At base line, three weeks, and six weeks, subjects were interviewed and examined, and serum antibody tests were performed, along with blood cultures for Borrelia burgdorferi. Entomologists confirmed the species of the ticks and classified them according to sex, stage, and degree of engorgement.

RESULTS

Erythema migrans developed at the site of the tick bite in a significantly smaller proportion of the subjects in the doxycycline group than of those in the placebo group (1 of 235 subjects [0.4 percent] vs. 8 of 247 subjects [3.2 percent], P<0.04). The efficacy of treatment was 87 percent (95 percent confidence interval, 25 to 98 percent). Objective extracutaneous signs of Lyme disease did not develop in any subject, and there were no asymptomatic seroconversions. Treatment with doxycycline was associated with more frequent adverse effects (in 30.1 percent of subjects, as compared with 11.1 percent of those assigned to placebo; P<0.001), primarily nausea (15.4 percent vs. 2.6 percent) and vomiting (5.8 percent vs. 1.3 percent). Erythema migrans developed more frequently after untreated bites from nymphal ticks than after bites from adult female ticks (8 of 142 bites [5.6 percent] vs. 0 of 97 bites [0 percent], P=0.02) and particularly after bites from nymphal ticks that were at least partially engorged with blood (8 of 81 bites [9.9 percent], as compared with 0 of 59 bites from unfed, or flat, nymphal ticks [0 percent]; P=0.02).

CONCLUSIONS

A single 200-mg dose of doxycycline given within 72 hours after an I. scapularis tick bite can prevent the development of Lyme disease.

Infection of mice with the agent of human granulocytic ehrlichiosis after different routes of inoculation

Population kinetics of the agent of human granulocytic ehrlichiosis (aoHGE) were examined after needle and tickborne inoculation of C3H mice. Blood, skin, lung, spleen, liver, kidney, brain, lymph node, and bone marrow samples were analyzed by using real-time polymerase chain reaction (PCR) at various intervals after inoculation, using a p44 gene target. The highest number of copies of the p44 gene target occurred in blood and bone marrow samples, emphasizing aoHGE leukocytotropism. Numbers of copies of the p44 gene target in other tissues reflected vascular perfusion rather than replication. Needle-inoculated infected mice had earlier dissemination, but kinetics of infection in both groups were parallel, with declining rates of infection by day 20 and recovery in some mice on days 20-60 after inoculation. On the basis of an aoHGE lysate ELISA, mice seroconverted by day 10 after inoculation. Therefore, real-time PCR is useful for quantitative studies with the aoHGE in experimental infections, and results showed that needle inoculation can be used to study the aoHGE infection because of its similarity to tickborne inoculation.

Effect of tick removal on transmission of Borrelia burgdorferi and Ehrlichia phagocytophila by Ixodes scapularis nymphs

The effect of feeding duration on pathogen transmission was studied for individual ticks infected with either laboratory or field strains of the Lyme disease spirochete Borrelia burgdorferi and field strains of Ehrlichia phagocytophila, an agent of human granulocytic ehrlichiosis. Infected nymphal Ixodes scapularis were allowed to feed individually on mice, and equal numbers were removed at 24-h intervals for < or =96 h. Mice were assayed for infection by culture, serologic testing, and polymerase chain reaction (PCR) analysis. Fed ticks were assayed by culture or PCR analysis. Transmission of B. burgdorferi did not occur during the first 24 h among 66 attempts, with maximum transmission occurring between 48 and 72 h. A model estimating the probability of infection from individual ticks removed by patients in a Lyme disease-endemic area yielded an overall probability of 4.6%. Infected I. scapularis nymphs transmitted E. phagocytophila within 24 h in 2 of 3 attempts, which indicates that daily tick removal may not be adequate to prevent human infection with this agent.

Localized intracoronary gamma-radiation therapy to inhibit the recurrence of restenosis after stenting

BACKGROUND

Although the frequency of restenosis after coronary angioplasty is reduced by stenting, when restenosis develops within a stent, the risk of subsequent restenosis is greater than 50 percent. We report on a multicenter, double-blind, randomized trial of intracoronary radiation therapy for the treatment of in-stent restenosis.

METHODS

Of 252 eligible patients in whom in-stent restenosis had developed, 131 were randomly assigned to receive an indwelling intracoronary ribbon containing a sealed source of iridium-192, and 121 were assigned to receive a similar-appearing nonradioactive ribbon (placebo).

RESULTS

The primary end point, a composite of death, myocardial infarction, and the need for repeated revascularization of the target lesion during nine months of follow-up, occurred in 53 patients assigned to placebo (43.8 percent) and 37 patients assigned to iridium-192 (28.2 percent, P=0.02). However, the reduction in the incidence of major adverse cardiac events was determined solely by a diminished need for revascularization of the target lesion, not by reductions in the incidence of death or myocardial infarction. Late thrombosis occurred in 5.3 percent of the iridium-192 group, as compared with 0.8 percent of the placebo group (P=0.07), resulting in more late myocardial infarctions in the iridium-192 group (9.9 percent vs. 4.1 percent, P=0.09). Late thrombosis occurred in irradiated patients only after the discontinuation of oral antiplatelet therapy (with ticlopidine or clopidogrel) and only in patients who had received new stents at the time of radiation treatment.

CONCLUSIONS

Intracoronary irradiation with iridium-192 resulted in lower rates of clinical and angiographic restenosis, although it was also associated with a higher rate of late thrombosis, resulting in an increased risk of myocardial infarction. If the problem of late thrombosis within the stent can be overcome, intracoronary irradiation with iridium-192 may become a useful approach to the treatment of in-stent restenosis.

Coinfection with Borrelia burgdorferi and the agent of human granulocytic ehrlichiosis suppresses IL-2 and IFN gamma production and promotes an IL-4 response in C3H/HeJ mice

Previously we demonstrated that Borrelia burgdorferi transmission by Ixodes scapularis suppressed IL-2 and IFN gamma production and promoted IL-4 production in mice. The present studies were conducted to determine whether coinfection with the human granulocytic ehrlichiosis (HE) agent would promote a Th2 cytokine response in mice. Transmission to the spleen of the agent of human granulocytic ehrlichiosis (aoHGE) and B. burgdorferi occurred 4 and 7 days, respectively, after tick infestation. Coinfection synergized to suppress splenic IL-2 production 7-14 days after tick infestion. Transmission of B. burgdorferi or aoHGE alone significantly decreased splenic IFN gamma 4-7 days after tick infestation, while coinfection suppressed IFN gamma production 7-14 days after tick infestation. Splenic IL-4 production was significantly increased 4 days after coinfection, and by day 10, aoHGE plus B. burgdorferi induced greater splenic IL-4 (57.2 pg/ml, 348% of control values) than either organism transmitted alone (aoHGE, 22.7 pg/ml, B. burgdorferi, 25.1 pg/ml). Coinfection enhanced expansion of splenic T cells, CD4+ lymphocytes and B cells while decreasing CD8+ T cells. These data demonstrate that aoHGE and B. burgdorferi, when cotransmitted, suppress a systemic IL-2 and IFN gamma response, while strongly promoting systemic IL-4 production in the susceptible host. The antigen(s) responsible for this polarization are unknown and will be the subject of future studies.

Sporadic fatal insomnia: a case study

A 58-year-old man died after a 27-month illness characterized by insomnia, confirmed by polysomnography. He was homozygous for methionine at codon 129 of the prion gene but had no mutation in the prion gene. Neuropathology showed thalamic and olivary atrophy and no spongiform changes. Paraffin-embedded tissue blotting demonstrated abnormal prion protein in the brain. This is the first case of the sporadic form of fatal familial insomnia with demonstration of the disorder by polysomnography.

Attachment of Borrelia burgdorferi within Ixodes scapularis mediated by outer surface protein A

Borrelia burgdorferi outer surface protein (Osp) A has been used as a Lyme disease vaccine that blocks transmission: OspA antibodies of immune hosts enter ticks during blood feeding and destroy spirochetes before transmission to the host can occur. B. burgdorferi produce OspA in the gut of unfed Ixodes scapularis ticks, and many spirochetes repress OspA production during the feeding process. This preferential expression suggests that OspA may have an important function in the vector. Here we show that OspA mediates spirochete attachment to the tick gut by binding to an I. scapularis protein. The binding domains reside in the central region and COOH-terminus of OspA. OspA also binds to itself, suggesting that spirochete-spirochete interactions may further facilitate adherence in the gut. OspA-mediated attachment in the tick provides a possible mechanism for how stage-specific protein expression can contribute to pathogenesis during the B. burgdorferi natural cycle.

The safety profile of the fluoroquinolones

BACKGROUND

Premarketing trials showed the fluoroquinolone agents to have a favorable side-effect profile, with treatment-related adverse events comprising gastrointestinal, central nervous system, and dermatologic effects that were generally mild and reversible on cessation of treatment. However, postmarketing surveillance studies have identified severe adverse events, including severe anaphylaxis, QTc-interval prolongation, and potential cardiotoxicity, associated with 3 quinolone agents that either resulted in the removal of the agent from the market (temafloxacin and grepafloxacin) or significantly restricted its use due to substantial mortality and morbidity associated with liver toxicity (trovafloxacin). To date, there have been no such significant adverse events associated with the older fluoroquinolone agents, including ciprofloxacin, ofloxacin, norfloxacin, and levofloxacin. However, there are fewer data from postmarketing surveillance studies on the most recently approved agents, such as moxifloxacin and gatifloxacin, or agents awaiting approval, such as gemifloxacin.

OBJECTIVE

This paper examines safety data from the premarketing trials and postmarketing surveillance studies of fluoroquinolones available in the United States.

METHODS

A MEDLINE search was performed to identify all English-language studies published since 1980 concerning the safety profiles of the fluoroquinolones.

CONCLUSIONS

The fluoroquinolone antibacterial agents offer broad-spectrum therapy in patients with a variety of infections. Given similar spectra of activity, the choice between quinolones may be based on differences in efficacy and safety or tolerability profiles. Most drug reactions involving these agents are minor and reversible on discontinuing treatment, but adverse effects can be associated with significant mortality and morbidity, as was seen in the case of trovafloxacin and temafloxacin.

Effects of grain processing and bovine somatotropin on metabolism and ovarian activity of dairy cows during early lactation

This study compared the effects of exogenous bovine somatotropin (bST) on the metabolism and ovarian activity of cows fed diets differing in ruminally degradable starch. Twenty-four multiparous and eight primiparous Holstein cows in early lactation were divided into four groups and fed diets containing 39% grain as steam-flaked sorghum or steam-rolled corn with or without bST for 90 d in a 2 x 2 factorial design. Flaked sorghum improved energy status of cows during early lactation, tending to increase plasma glucose and insulin. Administration of bST decreased plasma urea nitrogen and increased nonesterified fatty acids (NEFA). Plasma levels of beta-hydroxybutyrate (BHBA) and hepatic concentrations of triglycerides were not altered by treatments. Temporal changes in plasma glucose, urea nitrogen, NEFA, and BHBA were detected in a quadratic manner and insulin increased linearly with time, but treatments did not affect postpartum changes in these metabolites. There were greater decreases in body weight and net energy balance in cows on bST during the first 7 wk of treatment. Cows receiving bST took longer to reach the nadir of negative energy balance, and bST tended to delay the period to reach a positive energy balance. Follicular populations and incidence of cystic ovaries were not affected by treatments, but cows receiving bST had fewer double ovulations. Flaked sorghum increased plasma progesterone during the early luteal phase of the first two postpartum estrous cycles. Feeding more ruminally degradable starch improved the energy status and luteal activity of cows in early lactation.