Preparation of an acellular dermal matrix using the freeze-thawing technique with and without gamma irradiation

An acellular dermal matrix [ADM] is a dermal substitute in which the skin is treated to remove epithelial and dermal cellular components. To compare the histological and immunohistochemical structures of ADMs prepared using the freeze-thawing technique with or without gamma irradiation. Twenty-one human skin specimens were used and divided into three equal groups: group I [control group], group II, in which skin specimens were subjected to three repeated freeze-thawing cycles, and group III, in which skin specimens were subjected to three repeated freeze-thawing cycles and subsequent exposure to 5000 rad gamma irradiation. Skin specimens from the previous groups were examined histologically and immunohistochemically for laminin. A morphometric study was carried out for the determination of the number of cells per high-power field [hpf] in both the papillary and the reticular dermis. Both methods of ADM preparation resulted in extensive extraction of cellular components with preservation of the basic dermal architecture as there was a highly significant decrease in the number of cells/hpf in both layers of the dermis in groups II and III as compared with the control group [P<0.001]. However, there was further decellularization in group III as there was a highly significant decrease in the number of cells/ hpf in both the papillary and the reticular dermis in group III as compared with group II [P<0.001]. Immunohistochemical stain of laminin revealed preservation of the epidermal basement membrane in groups II and III. A combination of irradiation and a freeze-thawing technique is recommended in the preparation of ADM for efficient decellularization

Temporalis fascia versus composite cartilage perichondrial graft in the reconstruction of total and subtotal tympanic membrane perforations

Objective: The purpose of this study was to compare between temporalis fascia and composite cartilage perichondrium grafts in reconstruction of the total and subtotal tympanic membrane perforations

Study Design: Prospective study consisted of ninety five consenting patients with chronic inactive suppurative otitis media with total and subtotal perforations. The patients were classified into two groups; group A [75 ears in 75 patients] in whom cartilage graft was used and group B [20 ears in 20 patients] in whom temporalis fascia was used

Results: For group A tymapanic membrane closure was achieved in 71 patient [94.6%] while in group B tympanic membrane closure was achieved in 7 patients [35%]. The hearing results showed that, there was highly significant postoperative improvement in pure tone averages as well as air bone gap averages. In group A the air bone gap was closed to less than 10 dB in 21.7% and from 10 to 25 dB in 73.9% and to more than 25 dB in 4.4 %, on the other hand the air bone gap was closed to less than 10 dB in 16.7 % and from 10 to 25 dB in 66.6 % and to more than 25 dB in 16.7 % in group B. In this study, the average pre and postoperative air bone gap [500-4000 Hz] were 26.8 dB and 13 dB respectively, for cartilage group and 25.1 dB and 12.3 dB for fascia group

Conclusions: This study revealed that Composite cartilage perichondrial grafts are excellent graft material for total and subtotal perforations. The palisade technique is an effective and straight forward technique with high success rate and good hearing results with no postoperative complications

Cartilage tympanoplasty: a technique to combat eustachian tube dysfunction

This study included 199 cases suffering from inactive chronic suppurative otitis media and operated up on at the Otorhinolaryngology Department Mansoura University from 2000 to 2003. Patients were divided into 3 groups according to their Eustachian tube function [good, fair and poor]. Tympanoplasties were done using 3 types of graft materials [full thickness cartilage graft, partial thickness cartilage graft and temporalis fascia graft]. The take rate was better with good Eustachian tube function than poor Eustachian tube function in the 3 groups, in fascia group there was a significant difference between good and poor Eustachian tube function. There was no significant difference in hearing results between the fascia group and cartilage groups. Type A tympanogram was obtained in partial thickness cartilage graft and temporalis graft more than the full thickness cartilage graft. According to our results the use of cartilage is the preferred graft material for tympanoplasty in cases with poor Eustachian tube function

Detection of DNA of W. bancrofti in blood samples by QC-PCR-Elisa-based

An internal control was used in a polymerase chain reaction PCR-ELISA-based technique to detect the DNA repeat of the filarial parasite W. bancrofti. The sensitivity of the test could detect as low as one single microfilania added to 200 micro litre of blood. The assay was evaluated on field samples from persons living in areas endemic for filariasis. Examination of night blood of 113 individuals for the presence of microfilania by filtration revealed 44 microfilaria carriers. All microfilaria carriers were positive in the PCR-EL1SA and, in addition, 14 more samples were proven to contain parasite DNA. All the 58 proven cases had circulating filarial antigens in their serum samples. Assuming a sensitivity of PCR-ELISA on night blood of 100%, the sensitivity of night blood filtration was 74% and that of circulating filarial antigens is 100%. The data showed that the described PCR-ELISA method was capable of detecting the filarial infections. Consequently, this method facilitated the identification of the filarial endemic areas and the monitoring of control programs