Lyme disease—another transfusion risk?

Lyme disease (or Lyme borreliosis) is caused by a spirochetal bacteria, Borrelia burgdorferi. Increased recognition of the disease and increased exposure to the vector (ticks) capable of spreading B. burgdorferi from animal hosts have resulted in a rise in the number of cases of Lyme borreliosis reported in the United States. There are three stages of the clinical course of Lyme borreliosis; however, not all those infected will have typical manifestations of each stage, such as the arthritis of the third stage. Routine blood cultures will rarely document bacteremia and serologic testing is not yet reliable. Early treatment can prevent later stages of Lyme borreliosis. There is evidence that transmission of B. burgdorferi by blood transfusion is possible, but, to date, there has been no documentation of transfusion- associated Lyme borreliosis. Thus, no new recommendations for screening donors to identify possible carriers of B. burgdorferi are suggested at this time.     

Aedes albopictus (Diptera: Culicidae): an experimental and natural host of Dirofilaria immitis (Filarioidea: Onchocercidae) in Florida, U.S.A.

Females of an Aedes albopictus (Skuse) colony from southeastern Florida, U.S.A., ingested low (22.9 +/- 3.2 mg/Female) and high (243.2 +/- 37.6 mf/Female) numbers of microfilariae from a dog infected with Dirofilaria immitis (Leidy). High mortality of females occurred during the first 4 d after infection regardless of the number of microfilariae ingested; daily mortality was almost negligible during 5-15 d after infection. Percentage of survival 15 d after infection was higher (63%) in females that ingested low numbers of microfilariae than those (15%) that ingested high numbers of microfilariae. The development of most of the D. immitis larvae was arrested in late L1 stage with some of the L1 stage larvae becoming melanized intracellularly in the Malpighian tubule cells of Ae. albopictus. Fifteen days after infection, development of D. immitis to the infective L3 stage occurred in only 10.9% of the surviving F1 and F2 Ae. albopictus that ingested low numbers of microfilariae, but in 94% of Anopheles quadrimaculatus Say ingesting similar numbers of microfilariae, as a control. Females of Ae. albopictus ingesting high numbers of microfilariae had more surviving females with L3 than those ingesting low numbers of microfilariae. The number of L3 larvae in the Malpighian tubules, hemocoel, head capsule and proboscis ranged from 1 to 37 per female, indicating the potential of Ae. albopictus to transmit D. immitis. Development of D. immitis larvae was not affected by co-infection with Ascogregarina taiwanensis (Lien & Levine), although both parasites infect the Malpighian tubules, the first intracellularly and the second extracellularly. After one generation of selection, a strain of Ae. albopictus susceptible to D. immitis developed 2.5 times more L3 than the parent strain. These results show that a small portion of the natural population of Ae. albopictus is susceptible to infection with D. immitis and that susceptibility may be increased rapidly by selection. The presence of developing Dirofilaria sp. larvae in the Malpighian tubules of field-caught females indicated that Ae. albopictus may be infected naturally with D. immitis in Florida.     

Effect of VMH lesion on sucrose-Fed nociceptive responses

An initial analgesia followed by hyperalgesia to phasic noxious stimuli occurs after ingestion of sucrose ad libitum. However, the mechanism underlying hyperalgesia is not known. The present study was designed to explore the role of VMH in the mediation of the hyperalgesic effect of sucrose ingestion. Adult male albino rats received sucrose solution (20% p.o.) in addition to laboratory food pellets and tap water ad libitum. Their behavioural responses to various phasic and tonic noxious stimuli were recorded after 6, 12 and 48 h during pre and post-sucrose fed states in both the control and VMH lesion groups of rats. Sucrose feeding to control rats significantly reduced the tail flick latency (TFL) and threshold of vocalization during stimulus (SV) and after discharge (VA) indicating hyperalgesia, while the threshold of tail flick remained unaffected. The average pain rating during the formalin test (tonic pain) decreased significantly indicating analgesia. VMH lesion decreased the latency (mean +/- SD) for tail flick (11.26 +/- 4.65 from 15.61 +/- 5.12 s), threshold (median) for tail flick (0.04 from 0.08 mA), vocalization during stimulus (0.05 from 0.1 mA) and vocalization after discharge (0.15 from 0.2 mA), while the tonic pain rating increased, thereby suggesting a hyperalgesic state. However, sucrose feeding to lesioned rats neither potentiated nor attenuated their hyperalgesia. The results suggest that sucrose feeding for 6-48 h ad libitum produces hyperalgesia to phasic noxious and analgesia to tonic noxious stimuli, while VMH lesion produces hyperalgesia to both phasic and tonic noxious stimuli. Secondly, sucrose ingestion by VMH lesion rats does not affect their responses to pain, suggesting the possible role of VMH in the mediation of sucrose-fed nociceptive responses.     

How to Interpret Thyroid Biopsy Results: A Three-Year Retrospective Interventional Radiology Experience

Results of thyroid biopsy determine whether thyroid nodule resection is appropriate and the extent of thyroid surgery. At our institution we use 20/22-gauge core biopsy (CBx) in conjunction with fine-needle aspiration (FNA) to decrease the number of passes and improve adequacy. Occasionally, both ultrasound (US)-guided FNA and CBx yield unsatisfactory specimens. To justify clinical recommendations for these unsatisfactory thyroid biopsies, we compare rates of malignancy at surgical resection for unsatisfactory biopsy results against definitive biopsy results. We retrospectively reviewed a database of 1979 patients who had a total of 2677 FNA and 663 CBx performed by experienced interventional radiologists under US guidance from 2003 to 2006 at a tertiary-care academic center. In 451 patients who had surgery following biopsy, Fisher’s exact test was used to compare surgical malignancy rates between unsatisfactory and malignant biopsy cohorts as well as between unsatisfactory and benign biopsy cohorts. We defined statistical significance at P = 0.05. We reported an overall unsatisfactory thyroid biopsy rate of 3.7% (100/2677). A statistically significant higher rate of surgically proven malignancies was found in malignant biopsy patients compared to unsatisfactory biopsy patients (P = 0.0001). The incidence of surgically proven malignancy in unsatisfactory biopsy patients was not significantly different from that in benign biopsy patients (P = 0.8625). In conclusion, an extremely low incidence of malignancy was associated with both benign and unsatisfactory thyroid biopsy results. The difference in incidence between these two groups was not statistically significant. Therefore, patients with unsatisfactory biopsy specimens can be reassured and counseled accordingly.     

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.