In vitro and in vivo evaluations of increased effective beam width for heat deposition using a split focus high intensity ultrasound (HIFU) transducer

Purpose: To develop a novel and efficient, in vitro method for characterizing temporal and spatial heat generation of focused ultrasound exposures, and evaluate this method to compare a split focus and conventional single focus high intensity focused ultrasound transducer.

Materials and methods: A HIFU tissue-mimicking phantom was validated by comparing respective temperature elevations generated in the phantoms and in murine tumors in vivo. The phantom was then used in combination with IR thermography to spatially and temporally characterize differences in low-level temperature elevation (e.g. 3–5°C) produced by a single focus and split focus HIFU transducer, where the latter produces four simultaneous foci. In vivo experiments with heat sensitive liposomes containing doxorubicin were then carried out to determine if the larger beam width of the split focus transducer, compared to the single focus, could increase overall deployment of the drug from the liposome.

Results: Temperature elevations generated in the HIFU phantom were not found to be different from those measured in vivo when compensating for disparities in attenuation coefficient and specific heat, and between the two transducers by increasing the energy deposition. Exposures with the split focus transducer provided significant increases in the area treated compared to the single focus, which then translated to significant increases in drug deposition in vivo.

Conclusions: Preliminary evidence was provided indicating the potential for using this novel technique for characterizing hyperthermia produced by focused ultrasound devices. Further development will be required for its suitability for correlating in vitro and in vivo outcomes.     

Anesthetic implications of cervicofacial necrotizing fasciitis

Cervicofacial necrotizing fasciitis is a necrotizing soft tissue infection of face and neck spreading at the level of fascia. It has been described as a putrid ulcer, phagedaena, and hospital gangrene. It has a high mortality rate, and presents a challenge to anesthesiologists who must secure an airway to deliver anesthesia safely. We report a case of cervicofacial necrotizing fasciitis in which the patient underwent repeated radical surgical debridement of face and neck, including a mandibulectomy. These critically ill patients often present with sepsis and multiple system organ failure. Extensive preoperative evaluation, invasive monitoring, and possibly the use of vasopressors and inotropes are essential in treating these patients. The tracheas of these patients should remain intubated after initial debridement. Tracheostomy should be performed early. Antibiotic therapy, nutritional support, early debridement, and hyperbaric oxygen therapy all help to decrease mortality in these patients.     

Amodiaquine Resistance in Plasmodium falciparum Malaria in Afghanistan Is Associated with the pfcrt SVMNT Allele at Codons 72 to 76

Mutations in the Plasmodium falciparum genes pfcrt and pfmdr1 are selected by amodiaquine treatment in Africa. To examine the importance of these mutations in amodiaquine-treated Asian parasites, we determined pre- and posttreatment genotypes for amodiaquine treatment failures from a clinical trial in Afghanistan. The pfcrt codon 72 to 76 haplotype SVMNT was present in all samples tested, both before and after treatment. Amodiaquine did not clearly select for any pfmdr1 genotype, but a novel mutation, pfmdr1 N86F, was detected in four samples. We provide in vivo data to support the in vitro correlation between pfcrt SVMNT and increased resistance to the metabolite of amodiaquine.Amodiaquine (AQ), a 4-aminoquinoline related to chloroquine (CQ), has been used commonly as a monotherapy and now as a partner drug in artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated Plasmodium falciparum malaria. In many countries, predominantly in Africa, the in vivo efficacy of AQ was found to be good even in the face of increasing CQ resistance (12). However, reports of AQ resistance have come from South America, Asia, and East Africa (7, 8, 10).Mutations in the P. falciparum chloroquine resistance transporter gene (pfcrt) and multidrug resistance gene 1 (pfmdr1) have been associated with clinical resistance to both CQ and AQ (13). The presence of the pfcrt codon 72 to 76 haplotype SVMNT (Ser-Val-Met-Asn-Thr) correlates with high-level resistance to the AQ metabolite desethylamodiaquine (DEAQ) in in vitro tests (14) and has been detected with a high prevalence in parasite populations from Brazil, Papua New Guinea, Laos, Iran, and India (9, 18). Clinical trials in East Africa have also demonstrated high levels of in vivo resistance to AQ; in those studies, the parasites carried pfcrt codon 72 to 76 haplotype CVIET, and pfmdr1 polymorphisms 86Y, 184Y, and 1246Y were found to be selected after AQ treatment failure (5, 6, 11).A clinical trial performed in Nangahar Province, East Afghanistan, in 2002 and 2003 to explore possible replacement treatments for CQ showed very poor efficacies of both CQ and AQ monotherapy (adequate clinical and parasitological responses were seen in 11% and 9% of cases, respectively, by day 42) (4). Our aim in this study was to evaluate pre- and posttreatment samples from patients treated with AQ for pfcrt and pfmdr1 mutations and to determine which, if any, polymorphisms are associated with AQ treatment failure in Afghanistan.     

Anti-inflammatory and cytoprotective effects of selected Pakistani medicinal plants in Helicobacter pylori-infected gastric epithelial cells

Ethnopharmacological relevance

Helicobacter pylori infection is associated with gastritis, peptic ulcer, and gastric cancer. Due to its high global prevalence and uprising resistance to available antibiotics, efforts are now directed to identify alternative source to treat and prevent associated disorders. In the present study, effect of selected indigenous medicinal plants of Pakistan was evaluated on the secretion of interleukin-8 (IL-8) and generation of reactive oxygen species (ROS) in a bid to rationalize their medicinal use and to examine the anti-inflammatory and cytoprotective effects in gastric epithelial cells.

Materials and methods

AGS cells and clinically isolated Helicobacter pylori strain (193C) were employed for co-culture experiments. Anti-Helicobacter pylori activity and cytotoxic effects of the selected plants were determined by serial dilution method and DNA fragmentation assay respectively. ELISA and flow cytometry were performed to evaluate the effect on IL-8 secretion and ROS generation in Helicobacter pylori-infected cells.

Results

At 100 μg/ml, extracts of Alpinia galangal, Cinnamomum cassia, Cinnamomum tamala, Mentha arvensis, Myrtus communis, Oligochaeta ramose, Polygonum bistorta, Rosa damascena, Ruta graveolens, Syzygium aromaticum, Tamarix dioica, and Terminalia chebula exhibited strong inhibitory activity against IL-8 secretion. Of these, four extracts of Cinnamomum cassia, Myrtus communis, Syzygium aromaticum, and Terminalia chebula markedly inhibited IL-8 secretion at both 50 and 100 μg/ml. Cinnamomum cassia was further assessed at different concentrations against Helicobacter pylori and TNF-α stimulated IL-8 secretion, which displayed significant suppression of IL-8 in a concentration-dependent-manner. Among the plants examined against ROS generation, Achillea millefolium, Berberis aristata, Coriandrum sativum, Foeniculum vulgare, Matricaria chamomilla and Prunus domestica demonstrated significant suppression of ROS from Helicobacter pylori-infected cells (p < 0.01).

Conclusion

Results of the study revealed anti-inflammatory and cytoprotective effects of selected medicinal plants which could partially validate the traditional use of these plants in GI disorders particularly associated with Helicobacter pylori. Furthermore, results obtained may lead to possible future candidates of chemoprevention against peptic ulcer or gastric cancer.     

A family with Peutz-Jeghers syndrome

Three generations of a family with Peutz-Jeghers syndrome are described. The family chart is detailed.     

Precorneal Clearance of Mucoadhesive Microspheres from the Rabbit Eye

The ocular disposition of hydrated ¹¹¹In-labelled microspheres was investigated in the rabbit by gamma scintigraphy. Microspheres of cross-linked poly(acrylic acid) (Carbopol 907) were prepared by a w/o emulsification process. An in-vitro mucoadhesion test of prehydrated microspheres showed that greater adhesion was achieved to a mucus gel at pH 5·0 compared with pH 7·4. Clearance was a biphasic process with a rapid initial phase preceding a slower basal phase. When hydrated in pH 5·0 phosphate buffered saline, clearance during the basal phase was slower compared with a pH 7·4 buffered preparation. Both prehydrated preparations were retained on the preocular area during the basal phase for longer periods than non-hydrated microspheres. The retention on the ocular surface of approximately 25% of the instilled dose would suggest this technology will have application for controlled ophthalmic drug delivery.     

Modulation of the antitumor-activity of 5-Fluorouracil and cisplatinum by N-phosphonacetyl-L-aspartate in the murine colon-carcinoma number-26

Modulation of the antitumor activity of cisplatinum (CDDP) alone or in combination with 5-fluorouracil (FUra) by N-phosphonacetyl-L-aspartate (PALA) was investigated in Balb/c mice bearing colon 26 adenocarcinoma, using weekly i.v. push schedule (days 1, 7 and 14) with PALA (100 mg/kg) been administered 24 h prior to each drug treatment. Antitumor activity was assessed at the maximum tolerated dose (MTD) of treatment by determining tumor doubling time (TD), ratio of tumor size in drug treated to control values (T/C) and by kinetic of tumor regression, being partial (PR) or complete (CR) tumor regression. In this model system, FUra and CDDP alone and in combination did not produce significant antitumor activity. Although tumor reduction by these agents was primarily in the form of PR, regrowth of tumor was apparent following termination of treatment. In contrast, pretreatment with a nontoxic dose of PALA produced significant increase in CR rates, ranged from 6% of treated animals with CDDP to 19% of animals treated with FUra. Furthermore, the greatest therapeutic efficacy was achieved when PALA was used to modulate the antitumor activity of the combination of FUra and CDDP. Under these conditions 70% and 30% of treated animals achieved PR and CR, respectively. With the weekly schedule use herein, PALA did not potentiate significantly the toxicity of either FUra or CDDP. Potentiation of CDDP toxicity by PALA was observed when the drug was used in combination with FUra, requiring approximately 6 fold reduction in CDDP dose. In brief, using the optimal doses of FUra and CDDP in combination, PALA potentiated significantly the antitumor activity of the combination in mice bearing a tumor relatively resistant to FUra and CDDP when used as a single agent and in combination.