Effects of doxycycline on heartworm embryogenesis, transmission, circulating microfilaria, and adult worms in microfilaremic dogs

Tetracycline treatment of animals or humans infected with filariae that harbor Wolbachia endosymbionts blocks further embryogenesis, and existing microfilariae gradually die. This treatment also kills developing larvae and has a slow-kill effect on adult filariae, all presumably due to elimination of the Wolbachia. Also, Dirofilaria immitis microfilariae in blood collected from dogs up to 25 days after the last dose of doxycycline developed to infective L3 that were normal in appearance and motility in mosquitoes but did not continue to develop or migrate normally after subcutaneous (SC) injection into dogs. The present study was designed to determine whether heartworm microfilariae collected at later times after treatment would regain the ability to continue normal development in a dog. The study also was expected to yield valuable data on the effects of treatment on microfilariae and antigen levels and adult worms. The study was conducted in 16 dogs as two separate replicates at different times. A total of five dogs (two in Replicate A and three in Replicate B) infected either by SC injection of L3 or intravenous transplantation of adult heartworms were given doxycycline orally at 10mg/kg twice daily for 30 days, with three untreated controls. Microfilarial counts in the five treated dogs gradually declined during the 12-13 months after treatment initiation. Two dogs were amicrofilaremic before necropsy and three had 13 or fewer microfilariae/ml. Only one treated dog was negative for heartworm antigen before necropsy. Overall, treated dogs generally had fewer live adult heartworms than controls, and most of their live worms were moribund. All three control dogs remained positive for microfilariae and antigen and had many live worms. L3 from mosquitoes fed on blood collected 73-77 or 161-164 days after initiation of doxycycline treatments were injected SC into five dogs. None of the dogs injected with L3 from mosquitoes fed on blood from doxycycline-treated dogs were ever positive for microfilariae or antigen, and none had worms at necropsy; three control dogs were positive for microfilariae and antigen and had many live worms. These data indicate that doxycycline treatment of microfilaremic dogs gradually reduces numbers of microfilariae and blocks further transmission of heartworms. This latter effect should be highly effective in reducing the rate of selection of heartworms with genes that confer resistance to macrocyclic lactone preventives and microfilaricides. The data also suggest that doxycycline has a slow-kill effect on adult heartworms.

Transient tachypnea of the newborn: Is empiric antimicrobial therapy needed?

BACKGROUND

Transient tachypnea of the newborn (TTN) is a self- limited increase in the work of breathing in near- and full-term infants; it is attributed to a delay in the clearance of alveolar fluids. Prophylactic antibiotics are usually administered until blood cultures are reported negative for 48 hours.

OBJECTIVES

To prospectively compare outcomes of infants presented with classic TTN who were treated with or denied from intravenous antibiotics.

METHODS

A prospective cohort study was conducted on all infants admitted with classic TTN. Pre-set diagnostic criteria for classic TTN were applied in order to exclude other cases presenting with respiratory distress. Infants with classic TTN were stratified into two groups based on whether they received or did not receive antibiotics. The decision to administer antibiotics solely depended upon the style of the covering physician at the time of admission to the NICU. The following investigations were obtained from infants of both groups: blood culture, C-reactive protein, complete blood count, blood gas profile and chest X-ray.

RESULTS

A total of 15146 full-term infants were delivered during the study period; of them 923 were admitted to the NICU. Classic TTN was diagnosed in 168 infants; of them 106 (63%) received and 62 (37%) did not receive antibiotics. Two infants in the treated group and an infant in the non-treated group had microbiologically confirmed bacteremia. Infants in the treatment group stayed longer in the hospital (72 ± 6 vs. 48 ± 3 hrs). No recorded cases required readmission in either group.

CONCLUSIONS

With the application of strict criteria for classic TTN and the close observation in the NICU, the empiric use of antibiotics may be avoidable. Randomized controlled trials are needed to confirm the feasibility and safety of such approach.

Taurine for EPR dosimetry

EPR dosimetry is characterized by its non-destructive read-out and the possibility of dose archival. Here, taurine is proposed as a radiation dosimeter using EPR spectroscopy. The EPR spectrum of taurine was studied and assigned, and changes in the taurine EPR spectrum as a result of the change in both modulation amplitude and microwave power were quantified. For gamma radiation, the energy absorption coefficient and the collision mass stopping power of taurine were compared to the corresponding values of soft tissue and alanine, in addition to calculation of effective atomic numbers. The response of taurine to gamma radiation doses in the range from 0.1 to 50 kGy was investigated, as well as that in the range from 1.0 to 20.0 Gy using numerically enhanced EPR taurine spectra. Both response curves showed a linear behavior. In addition, the time dependence of radiation-induced radicals was studied for short (during the first 6 h after irradiation) and long (during about 3 months after irradiation) time periods, and a reasonable degree of stability of the taurine radicals was observed. It is concluded that taurine is a promising dosimeter, which is characterized by its simple spectrum, radical stability, and wide range of linear response to gamma radiation.

Radiological findings in gliosarcoma. A single institution experience

Gliosarcomas are rare tumors with a poor prognosis composed of intermingled malignant glial and sarcoma elements with an estimated incidence of 1.8-8.0% of all malignant astrocytic neoplasms. We aimed to review the imaging findings in eight patients with gliosarcoma who were treated in our center between 2002 and 2010. The diagnosis was confirmed by morphological and immunohistochemical stains. This study, to the best of our knowledge, is the largest describing the imaging manifestations of this tumor. Although our study revealed no unique radiological features for gliosarcoma, it is important to note that they all demonstrated either dural or ependymal involvement or both. Calcification, hemorrhage or cystic components are described with a tendency for a ring enhancement pattern. Interestingly pre-existing benign looking lesions and associated remotely located small meningiomas are also described.

[Cervical chondrosarcoma: about two cases]

Chondrosarcoma is a primary malignant bone tumor. The location in the vertebral bodies is rare. Its diagnosis is difficult and it is confirmed by histopathology. We report two cases of cervical chondrosarcoma in two men aged respectively 70 and 40 years. Symptomatology was cervicobrachial neuralgia and motor deficit. Both patients were operated and the treatment completed by radiotherapy.

[Ochronosis: report of two familial cases]

BACKGROUND

Ochronosis of alkaptonuria is a rare hereditary autosomal recessive disease in which there is an absence of homogentisic acid oxidase resulting in accumulation of homogentisic acid in tissues.

AIM

To report a new case of alkaptonuria

CASE REPORT

A 49-year-old man had been followed for 4 years for chronic lombalgia and arthropaty of two knees. He is married to his cousin and father of 4 girls. His parents are also cousins. The clinical examination has found a cutaneuous pigmentation and a lumbar stiffness. At biological checking, creatininemia was at 190 μmol/L and there are not inflammatory indicators. The radiography have shown a discal dorsolumbar calcifications, anterior inter somatic bridges and bilateral arthritis of knees without articular chondrocalcinosis. The diagnosis of ochronosis have been suspected and confirmed by the blackness of urine and the dosage of alkaptonuria. The patient has been treated symptomatiquely. Familial investigation have revealed that his daughter suffered from the same disease with the notion of blackness of urine. She is 12 year old and she's asymptomatic on the osteoarticular level.

CONCLUSION

Alkaptonuria causes a degenerative arthropaty which can endanger functional prognosis. Early diagnosis and scanning of this innate error of metabolism by genetic study play a fundamental interest, especially for molecular and genetic advisement.