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OTA Vertical File by Author
No full textThis document presents different types of OTA publications by author
Ecology of A.carbonarius and ochratoxin A production in vine fruits and control in the production chain
No full textThis study examined black aspergilli, especially A. carbonarius and A. niger and
ochratoxin A (OTA) contamination of grapes, during drying and industrial processing
of dried vine fruits. This was complemented by studies on potential control using
preservatives and physical factors such as modified atmospheres. Fungal population
kinetics were determined in relation to grapes at harvest, and during drying at three
different altitudes (sea level: 0-200 m; medium level: 250-500 m; high level: >500 m)
in two seasons. At pre-harvest, A. niger aggregate species were the predominant
fungal species while A. carbonarius was occasionally isolated, in both years studied.
Both altitude and bunch position affected black aspergilli population dynamics.
Overall, they were increased during drying. However, both black aspergilli groups
were mostly isolated, at low and medium altitudes (<500 m). OTA contamination
was influenced by bunch position, although altitude did not significantly influenced
amounts. The fungal biodiversity was decreased during sun-drying of sultanas. The
widest diversity of species occurred at the sea level. However, A. niger aggregate,
were dominant during drying. Time of drying and altitude significantly influenced
fungal loads of black aspergilli. In contrast, OTA production (ca 0.001 - 0.0025 μg g
-
1
) was not significantly influenced by altitude and drying time. Shannon Index of
Biodiversity (H), for pre-harvest and pos-harvest studies, was determined for the first
time.
A. niger aggregate (ca 5.0 Log10 CFUs g
-1
) was predominant during industrial
processing, while A. carbonarius was only isolated at low levels (1.5-2.0 Log10 CFUs
g
-1
). Heat treatment (up to 90
o
C) appeared to be the key-procedure for the
elimination of fungal populations. In the contrary, SO2 treatment did not statistically
alter fungal population dynamics. OTA contamination was not significantly affected
by industrial processing.
In vitro studies conducted on both White Grape Juice Medium (WGJM) and in
sultanas with strains of A. carbonarius originated from Cretan sultanas and compared with a strain isolated from Italian wine grapes. They examined the impact of sodium
metabisulphite (NaMBS), elevated CO2 (up to 50%) concentrations and aw levels, on
black aspergilli spore germination, growth and OTA production. Moreover, fungal
interactions in vitro and in situ were also investigated.
In general, spore germination occurred over a wide range of sodium metabisulphite
concentrations, although germ tube extension was significantly controlled. At ≥ 750
mg L
-1
NaMBS, no spore germination was observed while both mycelial growth and
OTA production were completely inhibited. Medium concentrations of NaMBS (≤
250 mg L
-1
) enabled optimum spore germination, growth and OTA production (x
0.965 aw). The efficacy of controlled atmospheres x aw showed that there was very
little inhibitory effect on spore germination. However, both germ tube extension and
fungal growth were inhibited by 50% CO2. After 10 days, growth was not as
effectively controlled. Aw had a bigger effect on OTA production than modified
atmospheres. In situ experiments on sultanas confirmed these results. Competition
and dominance of A. carbonarius over other fungal species showed that aw and
temperature influenced Indices of Dominance and OTA production. In vitro and in
situ, OTA production by A. carbonarius was significantly influenced by the fungal
competitor used
Aspergillus niger ochratoxinase is a highly specific, metal-dependent amidohydrolase suitable for OTA biodetoxification in food and feed
No full textMicrobial enzymes can be used as processing aids or additives in food and feed industries. Enzymatic detoxification of ochratoxin A (OTA) is a promising method to reduce OTA content. Here, we characterize the full-length enzyme ochratoxinase (AnOTA), an amidohydrolase from Aspergillus niger. AnOTA hydrolyzes OTA and ochratoxin B (OTB) mycotoxins efficiently and also other substrates containing phenylalanine, alanine, or leucine residues at their C-terminal position, revealing a narrow specificity profile. AnOTA lacks endopeptidase or aminoacylase activities. The structural basis of the molecular recognition by AnOTA of OTA, OTB, and a wide array of model substrates has been investigated by molecular docking simulation. AnOTA shows maximal hydrolytic activity at neutral pH and high temperature (65 °C) and retained high activity after prolonged incubation at 45 °C. The reduction of OTA levels in food products by AnOTA has been investigated using several commercial plant-based beverages. The results showed complete degradation of OTA with no detectable modification of beverage proteins. Therefore, the addition of AnOTA seems to be a useful procedure to eliminate OTA in plant-based beverages. Moreover, computational predictions of in vivo characteristics indicated that AnOTA is neither an allergenic nor antigenic protein. All characteristics found for AnOTA supported the suitability of its use for OTA detoxification in food and feed.Peer reviewe
Genetic polymorphism of enzymes that scavenge reactive oxygen species and lung cancer susceptibility in slovene patients
No full textOchratoxin A in Roasted Coffee from French Supermarkets and Transfer in Coffee Beverages: Comparison of Analysis Methods
No full textThe OTA content of 30 roasted coffees purchased in French supermarkets was evaluated by two validated different methods: one using immunoaffinity column (IAC) clean-up after alkaline extraction; the second using toluene extraction under acidic conditions. OTA recoveries (0.5 to 5 µg/kg) ranged from 16–49% with the alkaline extraction method and 55–60% with the acidic method. OTA recoveries from prepared beverages were similar with all methods (75–80%). All samples containing OTA ranged from trace (<LOQ) to 11.9 µg/kg. About 20 to 140% of OTA passed through the beverages. Recoveries of over 100% of OTA in beverages were due to three types of interferences: (i) formation of open-ring OTA (OP-OA) during alkaline extraction, (ii) isomerization of OTA during roasting, and (iii) presence of the nonchlorinated analogue OTB. The first two types of interference generate OTA derivatives that are not recognized by OTA antibodies, while OTB cross-reacts with OTA-antibodies. These analytical problems will seriously impact the amount of OTA detected, especially at the levels close to the limits from the EU legislation. Underestimation of OTA could be highly dangerous for health
Monolithic fully balanced OTA based high frequency filters
No full textTypescript (photocopy).This research involved the development of a design approach and the necessary circuit elements for high-frequency continuous-time monolithic filters to be implemented in a standard CMOS process. The investigation began by comparing the commonly used monolithic gain blocks and their topologies to infer which are best suited for high frequency filtering applications. The transconductance amplifier topology is shown to be superior to traditional operational (voltage) amplifier topologies in bandwidth and excess phase. The open loop (transconductance amplifier based) integrator is also shown to provide better characteristics than the closed loop (Miller) integrator. The reported advantages of fully balanced structures led to choice of a fully balanced OTA based filter topology, which is derived from the familiar (op amp based) Tow-Thomas biquad. To improve the linear input range of the transconductance amplifier, a voltage source terminated input stage is utilized. The OTA design is limited in several aspects (CMRR, PSRR, linearity) by device matching. The effects of mismatches in the input pair, current mirror gains, input signals and load capacitors is examined extensively. The average OTA shows measured output current nonlinearity of.88% over a 4V[subscript PP] input range. The OTA transconductance is adjusted with a novel adjustable CMOS voltage source for which a design and experimental results are presented. Filters have been fabricated and tested in the 300-400 kHz range. All filters tested were post-fabrication adjustable to nominal specifications (f[subscript o] = 375 kHz, Q = 3.25). The 1% THD input amplitude was over 1.75 V[subscript PP], and the corresponding dynamic range was approximately 70 dB. The low frequency PSRR was -60 dB, and the critical frequency PSRR was -40 to -50 dB. Since the OTA linearity is achieved through device matching, the linearity is not directly frequency limited, and shows potential for filter applications above 1 MHz. Next generation filters will use better layout techniques to improve the distortion performance
Gnathia nubila Ota & Hirose, 2009, n. sp.
No full textGnathia nubila n. sp. (Figs. 1 –3, 6 A, B) Material examined. Holotype. 9.1 mm (NSMT-Cr 20878), from gill filaments and gill arches of spotted eagle ray Aetobatus narinari (Euphrasen, 1790) caught by commercial fishing (boat out of Hama Fishing Port), Nakagusuku Bay (26 °N, 127 °E), Okinawa Island, Ryukyu Archipelago, southwestern Japan. 30 November 2007, coll. Y. Ota. Paratypes. Two males and 4 females from the same fish host as the holotype (NSMT Cr 20879). One male and 19 larvae from gill filaments and gill arches of A. narinari caught by commercial fishing (Okinawa City Fishing Port), Nakagusuku Bay (26 °N, 127 °E), 13 September 2006, coll. Y. Ota (NSMT-Cr 20880). Description. Male (Figs. 1, 2). Body 9.0–10.0 mm (9.3 ± 0.5 mm, n = 4). Pigmentation of live specimens white; digestive organs black due to congealed host blood. Cephalosome (Fig. 1 A–C). Cephalosome covered with tubercles and setae, almost square with posterior margin convex, about one-fifth of total length. Posterior median tubercle prominent. Frontal border medially opened by 2 frontolateral processes with tubercles and several submarginal setae. Apex of mediofrontal process bifit and dentate (Fig. 1 D). Eyes well developed, about one-fourth length of cephalosome. Supraocular lobe low, not acute. Dorsal sulcus deep and narrow. Pereon (Fig. 1 A). All pereonite lengths about half of total length. Pereonite 1 short, not fused, reaching lateral margin of cephalosome. Pereonites 2–6, sparsely covered with setae and tubercles. Widths of pereonites 2, 3, and 4 similar. Pereonite 2 as long as pereonite 3 and slightly shorter than pereonite 4. Anterior constriction and anterolateral lobe present on pereonite 4. Pereonites 5 and 6 combined subequal in length to pereonites 2–4 combined. Areae laterales and lobi laterals present on pereonites 5 and 6, respectively. Pereonite 7 short and narrow, overlapping pleonite 1. Pleon (Fig. 1 A). Lateral margins of pleonites 1–5 fringed with long setae. Lengths of pleonites and pleotelson about one-quarter of total length. Epimera prominent on pleonites 3–5. Pleotelson (Fig. 1 D). Pleotelson narrow, covered with pectinate scales. Eight setae on lateral margin and 1 pair of setae on both dorsal surface and distal apex. Mandible (Fig. 1 E). Mandible length two-thirds of cephalosome length. Apex curved inward. One mandibular seta present near armed carina on mid-dorsal surface. Dentate blade occupies about two-fifths of mandible length. Basal neck and erisma prominent. Antennae. Antenna 1 (Fig. 1 F). Peduncle articles 2 and 3 covered with pectinate scales. Three, 4, and 1 feather-like bristles on distal margins of peduncles 1, 2, and 3, respectively. One seta on internal margins of peduncle 2, and several setae on external and distal margins of peduncle 3. Flagellar articles bearing an aesthetasc on both articles 3 and 4. One seta on distal margin of article 3. Article 5 with 1 feather-like bristle terminating in 3 setae and 1 aesthetasc. Antenna 2 (Fig. 1 G). Two feather-like bristles and several setae present on peduncle 4. A few setae present on distal margins of flagellar articles 1–6. Article 7 terminates in 5 setae. Maxilliped (Fig. 2 A). Endite reaches distal margin of palp article 1. Palp articles 1, 2, 3, and 4 bearing 6, 8, 5, and 9 plumose setae on external margins, respectively. Article 4 terminates in 4 simple setae. Pylopod (Fig. 2 B). Pylopod 3 articled. Several setae present on distal margins of articles 1 and 2. Article 1 large and elliptical, with 2 areolae, and 76 plumose setae on internal margin. A few setae and 1 feather-like bristle present near outer margin. Article 2 circular and fringed with fine setae. Article 3 minute. Pereopods (Fig. 2 C). Pereopod 2 bearing many setae; longer on outer margin than on inner. Pectinate scales on each article except basis; fine setae on inner margins of all articles. Basis oblong, bearing 2 featherlike bristles on outer margin. Ischium similar in length to basis, becoming larger distally. Merus about half length of ischium. Carpus rectangular and similar in length to merus. Propodus rectangular, about 1.2 times longer than carpus; bearing 2 spines on inner-mid and inner-distal margins. Dactylus with a few setae, terminating in unguis. Length of dactylus and unguis combined about half that of propodus. All pereopods similar in shape, size, and setation. Pleopods (Fig. 2 D). Pleopodal peduncle inner margin fringed with fine setae. One seta on outer distal corner, and a coupling hook on inner margin. Both pleopodal rami oval and equal in length. All pleopods subequal in shape. From 7 to 9 plumose setae and 1 simple seta (pl. 1, 2, 4) on exopods: pleopod 1; 7 plumose setae, pl. 2–4; 8, pl. 5; 9. From 4 to 8 pumose setae and 1 simple seta (pl. 2, 3) on endopods: pleopod 1; 6 plumose setae, pl. 2; 4, pl. 3–5; 8. Appendix masculina extending beyond half length of pleopod 2 endopod. Uropods (Fig. 1 D). Both rami subequal in length, extending beyond apex of pleotelson. Exopod bearing 19 setae and 7 plumose setae on external and internal margins, respectively. Endopod bearing 9 setae and 9 plumose setae on external and internal margins, respectively. Several feather-like bristles on dorsal surface. Penes (Fig. 2 E). Penes composed of 2 contiguous papillae and not prominent. Female (Fig. 3). Body 7.4 –8.0 mm (7.7 ± 0.3 mm, n = 4). Pigmentation of live specimens white. Cephalosome (Fig. 3 A–C). Cephalosome with several setae. Frontal margin slightly convex; pair of spots present. Pereon (Fig. 3 A, B). Pereonite 1 short, not fused, with central part protruding forward. Pereonites 3–6 oval, with 2 sutures, widths about two-thirds of lengths. Lateral shields of pereopods 4–6 visible dorsally. Pleon (Fig. 3 A, B). Several setae on pleonites 1–5 subequal in length. Pleotelson (Fig. 3 D). Two pairs of setae on lateral margin and apex. Antennae (Fig. 3 E, F). Setae on peduncle articles of both antennae fewer than in male. No pectinate scales on peduncle articles. Maxilliped (Fig. 3 G). Inner margin of basis and endite covered with pectinate scales. Endite reaches half length of palp article 1. Nine, 7, 9, 6, and 8 plumose setae on basis and articles 1, 2, 3, and 4, respectively. Oostegite elliptical. Pylopod (Fig. 3 H). Pylopod composed of 3 articles. Articles 1 and 2 covered with pectinate scales and fringed with fine setae on inner margins. Article 1 with suture bears 10 setae on lateral and distal margins. Article 2 rectangular, bearing 6 setae on distal margin. Article 3 minute. Pereopods (Fig. 3 I). Pereopods bear fewer setae than those of male; not covered with pectinate scales. Pereopods 5 and 6 larger than other pereopods. Pleopod (Fig. 3 J). One aesthetasc on outer margin of peduncle. Exopods and endopods oval, with 8 (exopods) or 6 (endopods) setae on distal margins, all vestigial. All pleopods subequal in shape. Uropod (Fig. 3 D). Uropodal rami slightly extended beyond apex of pleotelson. Exopod bears 19–21 setae on margin. Endopod bears 14–15 setae on margin. Immature praniza larva (Figs. 4, 7 A, B). Body 7.6–9.7 mm (8.4 ± 0.6 mm, n = 19). Dorsal thorax of live specimens black with white cloud-like pattern (Fig. 7 A); ventral thorax has distinct white line (Fig. 7 B). Distinct brown spot on eyes. Lateral margins of pleonites have brown pattern (see Fig. 7 A). Cephalosome (Fig. 4 A). Triangular, length same as width. Anterior margin of labrum straight. Eyes occupying half length of cephalosome. Pereon (Fig. 4 A, B). Pereonite 1 short. Pereonite 2 subequal in width to pereonite 3, with convex anterior margin. Pereonite 3 slightly longer than pereonite 2. Lateral shields of pereopods 4–6 visible in dorsal view, elliptical. Pleon (Fig. 4 A). Pleonites 1–4 subequal in length and slightly shorter than pleonite 5. Pleotelson (Fig. 4 C) with dentate lateral margin, bearing 3 pairs of setae on dorsal surface and apex. Antennae (Fig. 4 D, E). Internal margins of peduncles 2 and 3 of antenna 1 fringed with fine setae. Internal margins of peduncles 3 and 4 of antenna 2 fringed by fine setae. Mouth parts. Mandible (Fig. 4 F) with 9 teeth. Maxillule (Fig. 4 G) with 2 slender articles, fine setae on outer margin projecting to posterior, 7 teeth on apex. Paragnath (Fig. 4 H) slightly curved. Maxilliped (Fig. 4 I) composed of basis and 2 -articled palp. Basis with 1 coupling hook on inner margin and endite with 1 seta. Apex of palp 1 slightly dentate. Apex of palp 2 divided into 2 parts; 1 seta and 1 tooth on inner apex, 5 setae and 1 spine on outer part. Gnathopod (Fig. 4 J) pereopodal in shape with reduced carpus. One projection on distal margin of merus. Propodus with distal bulbous protrusion. Dactylus terminating in sharp, pointed unguis. Pereopods. Pereopod 2 (Fig. 4 K) more slender than that of male. Inner margins of carpus and propodus covered with pectinate scales. Pleopods (Fig. 4 L). Exopod fan-shaped with 7–9 plumose setae on distal margins. Endopod rectangular and as large as exopod; 7 or 8 plumose setae on distal margins. All pleopods subequal in shape. Uropod (Fig. 4 C) just reaches apex of pleotelson. Exopod bears 6 setae and 4 plumose setae on margin. Endopod bears 2 setae and 7 plumose setae on margin. Etymology. The specific name nubila is derived from the Latin meaning “cloudy”, referring to the larval thorax pattern. Remarks. Among Gnathia species described so far worldwide, the body length, and shape of the cephalosome and pleotelson of male G. nubila is most similar to those of G. grandilaris. However, the mediofrontal process of G. grandilaris is triangular-shaped lobe and conical (Coetzee et al. 2008) (G. grandilaris has the bifit one). Because G. trimaculata and G. m a c u l o s a have been found from this area (Ota & Hirose, 2009), these species may be found with G. nubila, but they are distinguished from G. nubila by the following features. Gnathia trimaculata has a mediofrontal process on the frontal border and a more slender pylopod (Coetzee et al. 2009). Gnathia maculosa is smaller (3.9–5.8 mm) and lacks a mediofrontal process (Ota & Hirose, 2009). Frontal borders of G. n o t o s t i g m a Cohen & Poore, 1994 and G. c o o k i Müller, 1989 are also similar in shape to that of G. nubila. However, G. notostigma has very pronounced paraocular tubercles and wider pleotelson (Cohen & Poore, 1994). Gnathia cooki has long and basally broadened penes and a wider pleotelson (Müller, 1989). Because species descriptions of gnathiids have traditionally been based on the morphology of adult males, detailed descriptions of larvae and female adults are lacking in many literatures. Females of the genus Gnathia have been described in detail for the following species: G. firingae, G. c a m u r i p e n i s, G. limicola, G. m a c u l o s a, G. a f r i c a n a, G. pantherina, G. p i l o s u s, G. gurjanovae, and G. trimaculata (Müller, 1991; Smit & Basson, 2002; Smit et al. 2002; Tanaka, 2004; Golovan, 2006; Ota et al. 2007; Coetzee et al. 2008; Ota & Hirose, 2009). Gnathia maculosa most closely resembles G. nubila. However, the frontal border of G. nubila has a pair of spots, the pleopodal rami are oval, and the body is larger (7.4 –8.0 mm). The pleopodal rami of G. m a c u l o s a are fan-shaped, and the body length is smaller (4.4–5.5 mm) than that of G. nubila (Ota & Hirose, 2009). Detail descriptions of praniza larvae were limited worldwide; G. firingae, G. africana, G. pantherina, G. camuripenis, G. limicola, G. capillata, G. grandilaris, G. trimaculata, and G. m a c u l o s a (Müller, 1991; Smit et al., 1999; Smit & Basson, 2002; Tanaka, 2004; Nunomura & Honma, 2004; Ota et al., 2007; Coetzee et al., 2008, 2009; Ota & Hirose, 2009). Among the gnathiid larvae described so far, G. nubila is most similar to G. grandilaris. However, G. grandilaris lacks a distinct brown spot on the eyes and a distinct white line on the ventral thorax, and it has a shorter pleotelson (Coetzee et al. 2008). Gnathia capillata, G. trimaculata, and G. maculosa larvae have all been found as ectoparasites on elasmobranchs from Japan; these 3 species are distinguishable from G. nubila as follows. Gnathia capillata has a wider pleotelson, and its pereonite 4 is distinctively separated from pereonites 5 and 6 (Nunomura & Honma, 2004). Gnathia trimaculata has yellow-greenish color with black spots on the thorax and its shorter pleotelson (Coetzee et al. 2009). Gnathia maculosa has wider pleotelson, shorter body length in the immature stage (4.2–5.8 mm), and white speckled or dappled pattern on the thorax (Ota & Hirose, 2009). Praniza larvae of G. c a m u r i p e n i s and G. limicola have also been described from the Ryukyus. Gnathia nubila is easy to distinguish from these 2 species by the following criteria: the body lengths of immature G. camuripenis and G. limicola are 3 mm, and the pleotelson is wider and not elongated (Tanaka, 2004; Ota et al. 2007).Published as part of Ota, Yuzo & Hirose, Euichi, 2009, Gnathia nubila n. sp. and a new record of Gnathia grandilaris (Crustacea, Isopoda, Gnathiidae) that parasitizes elasmobranchs from Okinawan coastal waters, Japan, pp. 43-55 in Zootaxa 2238 on pages 44-51, DOI: 10.5281/zenodo.19046
A 10 fJ·K <sup>2</sup>Wheatstone Bridge Temperature Sensor with a Tail-Resistor-Linearized OTA
No full textThis article describes a highly energy-efficient Wheatstone bridge temperature sensor. To maximize sensitivity, the bridge is made from resistors with positive (silicided diffusion) and negative (poly) temperature coefficients. The bridge is balanced by a resistive (poly) FIR-DAC, which is part of a 2nd-order continuous-time delta-sigma modulator (CT Δ Σ M). Each stage of the modulator is based on an energy-efficient current-reuse OTA. To efficiently suppress quantization noise foldback, the 1st stage OTA employs a tail-resistor linearization scheme. Sensor accuracy is enhanced by realizing the poly arms of the bridge and the DAC from identical unit elements. Fabricated in a 180-nm CMOS technology, the sensor draws 55 μ W from a 1.8-V supply and achieves a resolution of 150 μ K rms in an 8-ms conversion time. This translates into a state-of-the-art resolution figure-of-merit (FoM) of 10 fJ · K2. Furthermore, the sensor achieves an inaccuracy of ±0.4 °C (3 σ) from -55 °C to 125 °C after a ratio-based one-point trim and systematic non-linearity removal, which improves to ±0.1 °C (3 σ) after a 1st-order fit.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
OTA, the authors reply
No full textWe read with great interest the comment by Dr. W. T. Ng
concernig our article regarding the one-trocar appendectomy
(OTA) published on ‘‘Surgical Endoscopy’’.
The aim of our article was to underline the interest of
OTA and in particular to raise a question about its use
also in adult patients and by reading your letter we have
achieved this objective.
Certainly, as you have underlined, this procedure is
easy to adopt in pediatric patients [3, 6] thanks to the
small dimension of the operative chamber and the possibility
of easily extracting the appendix through the
umbilical orifice. We think that the same technique of
OTA can also be adopted safely in adults; the 84.6%
success rate presented in our article compared to the
100% rate of previous published papers does not depend
on the authors’ lack of experience, but only on the anatomic
conditions and on the degree of inflammation of
the appendix [1, 2].
Our current strategy with patients with suspect appendicitis
(children or adults) is to start the operation
with laparoscopic procedure by using operative optics;
then, if the surgeon thinks that it is possible to complete
the procedure by using only one trocar, he performs
OTA. If the appendix it is fixed or in retrocecal position,
we can insert one or two more ports and complete the
procedure in laparoscopy. It is also possible to perform
a mixed procedure if the surgeon prefers to complete the
procedure in open surgery by using a McBurney incision
[4–6].
The technique described by Dr. Ng, in which endoloops
are used, seems a little bit complicated compared
to the simple and linear one-trocar technique that we
have reported. As Dr. Ng certainly knows, with only
one trocar it is possible to dissect, to section, and to
coagulate by using different instruments; for this reason
also a fixed appendix can be mobilized [5, 6].
We believe that the OTA, as clearly appears from our
paper and from other articles published in the international
literature, presents several advantages compared
to the three-trocar procedure, but the surgeon’s experience
in performing this techniques is fundamental [3–6].
Several groups prefer to adopt the three-trocar
procedure because they do not have the operative optics
and related instruments and also because they lack the
necessary experience with one-trocar procedures, and
for this reason they strongly criticize these groups who
routinely adopt OTA [5].
We think that one-trocar appendectomy is an easy
technique to perform in children, but also in adults; the
only problem which might occur at the beginning of the
experience consists of the difficulty of simultaneously
moving the optical aid and the surgical instrument.
The authors belive that the one-trocar appendectomy
is a good and feasible technique, and it represents a valid
alternative to other laparoscopic procedures for performing
appendectomy in pediatric and adult patients.
We think that the only ‘‘more sense’’ of this discussion
about OTA is that there exist several laparoscopic
procedures to be adopted in case of appendicitis (including
OTA), and the surgeon, through his own experience
and knowledge, must choose the most suitable
technique to adopt in each single case. No doubt Prof.
Ng agrees about this point
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