Abdominal wall reconstruction (the "mutton chop" flap).

Reconstruction of full-thickness abdominal wall defects can be a difficult surgical challenge. Reconstructing the epigastrium may be especially vexing. The use of prosthetic mesh has significant drawbacks, and the use of pedicled myofascial and myocutaneous flaps should be advantageous. We present 15 consecutive cases demonstrating highly successful reconstructions of massive abdominal wall defects using myofascial and myocutaneous flaps without prosthetic mesh. The extended rectus femoris flap, or "mutton chop" flap, which is capable of resurfacing the epigastrium, is described. Complications were minimal, and use of myofascial units, particularly the rectus femoris, should be considered as the technique of choice for reconstruction of major abdominal wall deficits.     

The Ecology of Scale: Assessment of Regional Energy Turnover and Comparison with Global Food (5 pp)

Goal, Scope and Background Obviously, people assume that the regional production and distribution of food requires less energy turnover, compared with global transports of food. Politicians claim the term “regionality”, maintaining that regionality is a medicine against wasting so much energy for the global food distribution. Additionally the energy turnover is causing pollution. But remarkably, there is a lack of empirical data to support this idea. At the same time, nobody really requires regional origin for non-food items, e.g. for bicycles, dishwashers, furniture or cars etc. The public mainstream asks for regional origin merely for food. Hence, the first scientific issue worked out in this paper is how the energy turnover of comparable food items can be measured, regarding the lifecycle of food in total. That means to investigate the partial systems of crop or breed, of food production, of packaging including transport and distribution up to the point of sale. Secondly, it has to be checked, if the assumed coincidence of low energy turnover and regional origin can be verified. The specific energy turnover, calculated in the unit [kWh per kg] or [kWh per l] of food, is investigated by comparing regional with global process chains for different food items. Two examples of food – fruit juices and lamb meat – are researched, by personal investigation worldwide. Firstly, fruit juices of high grade quality from Brazil, from European origin and from local German farmers are compared, in terms of energy. Secondly, a comparison of lamb meat from New Zealand and lamb meat from local German farmers is conducted. Lamb meat has been investigated, because it is shipped around the world as frozen natural food, not concentrated like juices. In addition, the business size of the food producers is researched for both examples. Methods As a part of LCA the energy turnover of each process step from the very beginning up to the point of sale is investigated. These primary results are the basic empirical data, in order to allocate the energy turnover at the food items as functional units. The results of regional, European-continental and of global process chains are compared. In addition, the issue is investigated, whether the specific energy turnover depends upon the business size. Results and Discussion Surprisingly, the data in both cases demonstrate a strong degressive relation of the specific energy turnover and the business size. Here it is not important, if the business is regional or not. Merely the efficiency and logistics of the production and the operations determine the specific energy turnover. These findings seem closely connected with the business size, because small companies are not able to invest in energy recovering and saving technology. The regional juices business is worsened by the huge number of smallsized transports of the crop and the nearly bottle-wise distribution. Regarding lamb meat we once more find the disadvantages of comparably small farms again. In addition, the German farmers need daily shepherds, fences by night, stables and usually additional feed during the wintertime. All these efforts are not necessary in New Zealand, where the climatic conditions and the open countryside with low population allow rather easy and low energy breeding of lamb. Conclusion The coincidence of economic and ecological facts is obvious. As a matter of fact, in economics there is a strong degressive relation between the production costs and the number of produced items. This relation is very well known as “Economy of Scale.” Our findings lead to similar conclusions, in terms of ecology. That means, the production ecology depends on the number of produced items. Additionally, our results demonstrate a minimum business size, so that we can claim an “Ecology of Scale” as well. However, on the other hand, the reported data and the conclusions are valid for the investigated food items – fruit juices and lamb meat – only. Nevertheless, one conclusion is already evident: The most popular claims for regional food production and distribution instead of global process chains are not generally valid. Small farmers basically need much more energy to produce and distribute their products, compared with bigger units. Both food items demonstrate clearly, that the ecological quality is mainly influenced by the operational efficiency and not by the marketing distance itself. Recommendation and Outlook Much more detailed data of all the investigated operational units, processing fruit juices and lamb meat, have been published (Fleissner 2001). As a further example, we investigate wine from different countries as a further example. Different from fruit juices, which can be shipped as a concentrate, and different from lamb meat, which is shipped as frozen food, wine of high grade quality is always bottled close to the place of origin. That means, that not only the food, but also the heavy weight packaging is transported around the world. So, we are very curious about the results, which we expect for 2004.     

The role of serum imbibition for skin grafts

Numerous studies of grafted skin suggest that full-thickness skin grafts are nourished by exudate from the recipient bed called a serum imbibition. However, whether serum imbibition by itself is sufficient for nourishment of skin grafts has not been shown definitely and directly. To clarify the role of serum imbibition, we performed a comparative study between 20 skin grafts and 20 musculocutaneous flaps. The nourishment of the cell in the skin graft is by serum imbibition. That in musculocutaneous flaps is mainly derived from blood supply. We evaluated the nourishment by means of the unique characteristics of the cell cycle. Once cells are put into a synthetic phase, they cannot reverse or stop the progress of the cell cycle. To take advantage of this characteristic of the cell cycle, prewounding methods (40 flaps were lifted once and put back to the original sites prior to the evaluation) were intended for the cells in pre-elevated skin to turn into a proliferating phase. Cells were examined by antibody against proliferating cell nuclear antigen immunohistologically, to determine whether they had turned into the proliferating phase or not. After 3 days, all flaps were reelevated; half (20 flaps) had their muscle layer and the neurovascular bundle removed to make a full-thickness skin graft. The rest (20 flaps) were only lifted. They were sutured back to the original sites. Ten skin grafts and musculocutaneous flaps each were harvested at 3 hours (1st day) and at 11 days (11th day) after the second operation. Bromodeoxyuridine, which is a thymidine analog and is taken into the cells in the synthetic phase, was introduced intraperitoneally 2 hours before the harvest. All flaps and grafts were evaluated histologically and immunohistologically. Proliferating cell nuclear antigen analysis showed that the prewounding method induced the cells of skin grafts and musculocutaneous flaps to proliferate before the implantation. Regarding the bromodeoxyuridine uptake, no significant differences could be seen between skin grafts and musculocutaneous flaps irrespective of their different nourishment. No structural changes, such as degenerative or necrotic, could be seen at the hair follicle and other glands even at the 11th day. Almost all of the layers of skin grafts survived as long as they were checked by light microscopy (hematoxylin and eosin stain). No differences could be seen between musculocutaneous flaps and skin grafts or between the 1st and 11th days in this study. We concluded that serum imbibition is sufficient for nourishment of skin grafts, just as blood supply is sufficient for nourishment of musculocutaneous flaps.     

Biologic activity of the tachykinins on lamb and sheep gallbladder

In this study, we examined the activity of the tachykinins (TKs) on lamb and sheep isolated gallbladder and whether the TKs are involved in the capsaicin-induced activity in these tissues. Substance P (SP) and physalaemin (PHYS) contracted lamb gallbladder, PHYS-induced striking tachyphylaxis. This tissue was nearly insensitive to neurokinin A (NKA), neurokinin B (NKB), septide, and capsaicin. As in lamb tissues, SP and PHYS both contracted sheep gallbladder although PHYS induced no tachyphylaxis. At doses that had no effect on lamb tissue, NKA, NKB, septide, and capsaicin contracted sheep gallbladder. Our findings indicate that TK receptors differ in adult and young ovine gallbladder. The activity of PHYS on lamb gallbladder could depend on the existence of an unusual binding site, carrying one or more residues critical for the N-terminal sequence present in PHYS but not in SP.     

The Boer goat. II. Growth, nutrient requirements, carcass and meat quality

Growth rates of Boer goats were generally lower than sheep and, under favorable nutritional conditions, weight gains of more than 200 g per day were obtained, against values of up to 176 g per day under extensive subtropical conditions. Lactation and pregnancy had a marked effect on ME intake, and the latter had an improved feed conversion ratio (6.06 kg/kg) in comparison to that of virgin does (10.96 kg/kg). Below 6% crude protein in the diet, feed intake is reduced and has negative effects on birth weights, growth and milk production. Little information is available on mineral requirements of goats. The carcass of Boer goats is generally leaner, less compact and has different carcass proportions than sheep. The relatively high collagen contents with lower solubility of Boer goat meat, has meant that the eating quality has been regarded as inferior to that of lamb and mutton. Breeding holds the key to improving tenderness of goat meat; different slaughtering techniques can be used as well. Boer goats have high potential as meat animals when yielding three kid crops in 2 years and when fed to gain more than 200 g/day.     

The importance of feet examination in sheep health management

Lameness is still the biggest welfare issue present on sheep farms. In order to prevent and control lameness outbreaks on sheep farms, a good set-up is required, as well as a systematic approach to examining the foot and limb. The cause of lameness cannot be assumed to be foot-rot, but instead there are a whole host of conditions. These may be of a microbial aetiology, such as scald or contagious ovine digital dermatitis, or of non-microbial aetiology, such as white-line lesions or toe granulomas. The consequences of lameness can be far reaching, not only affecting the number of lambs born, but also the size of the lamb and whether they manage to get in lamb the following year. It can result in the difference between making a profit or a loss in the financial year.     

Clinical definition of independent myocutaneous vascular territories.

The use of myocutandous flaps can increase the possibilities for construction in many cases by bringing in new blood supply to avascular areas by furnishing additional bulk for filling defects or covering bone grafts or other deep repairs, and sometimes by making longer flaps viable. Also, the need for delay procedures is decreased and sometimes avoided. In this paper we define the vascular territories of 13 clinical myocutaneous flaps, and we describe possible uses of them. Three illustrative clinical cases are presented, in which repairs were done with these flaps. The future uses of these flaps challenge the imagination. Knowledge about them may significantly alter the traditional approaches to flap designs and repairs.     

The impact of lambing stress on post-parturient behaviour of sheep with consequences on neonatal homeothermy and survival

During lambing the expression of an appropriate behavioural response from both the ewe and the lamb are extremely important to lamb survival. The aim of this study was to show the effect of length and difficulty of the birth process on the expression of maternal and neonatal behaviour with consequences on homeothermy and survival of the neonate lamb. Data were collected from 61 Finnish Landrace × Rahmani crossbred (second generation) primiparous ewes and their single born lambs. Based on the average length of parturition, the ewes were grouped into short birth (less than 32.5 min) and long birth (equal to or higher than 32.5 min) classes. The data recorded include maternal and neonatal behaviour, lamb body temperature over the first 3 days of life and survival rate of the neonate lamb during the first week after birth. Blood samples were also collected from the lamb, pre-suckling and at 24 and 72 h after birth. The obtained sera were assayed for thyroid hormones (T₃ and T₄) that are associated with heat production. Ewes that had prolonged and difficult births did not show competent maternal behaviour compared to mothers with short and un-complicated deliveries, as they were slower to begin grooming their lambs after birth, spent less time licking their lambs, made less low-pitched vocalizations and nosing, were more likely to show rejection behaviour (10.34 % vs 5.4 %, P < 0.05), and were more likely to move away when the lamb sought the udder in an attempt to suck (acceptance rate, 55.5 % vs 64.79 %, P < 0.05). Similarly, lambs from a prolonged and difficult birth were significantly less vigorous after birth, as they had taken more time to stand, reach the udder and to suck successfully. These lambs had lower serum concentrations of T₃ and T₄, and they also had a reduced ability to maintain body temperature after birth. This effect persisted over the first 3 days of life and was associated with higher neonatal mortality in the first week after birth (11.54 %), compared to lambs from short and non-stressful birth processes (2.86 %, P < 0.01). From the present study, it can be concluded that, prolonged deliveries with birthing difficulty were one of the main causes of death of large, single-born lambs, as these complications cause the expression of inappropriate behavioural responses from both the ewe and neonatal lamb. Thus, interventions designed to reduce the incidence of prolonged parturitions are likely to be associated with better welfare for the ewe and the lamb and consequently improved lamb homeothermy and survival.     

The role of the large superficial vein in survival of proximally based versus distally based sural veno-neuro-fasciocutaneous flaps in a rabbit model

A sural veno-neuro-fasciocutaneous flap in the New Zealand White rabbit was developed, and the role of the large subcutaneous lesser saphenous vein was investigated in proximally based versus distally based flaps. Retrograde dye injection showed that the lesser saphenous vein in rabbits has many valves with strong resistance against reflux. Twenty rabbits were randomly allocated into four groups of 10 flaps each. Group I consisted of proximally based flaps with the lesser saphenous vein intact (outflow) in the veno-neuro-adipofascial pedicle. Group II also consisted of proximally based flaps but the lesser saphenous vein was ligated at 1 cm proximal to the pedicle. Group III consisted of distally based flaps with the lesser saphenous vein intact (inflow) in the veno-neuro-adipofascial pedicle. Group IV also consisted of distally based flaps, but the lesser saphenous vein was ligated at 1 cm distal to the pedicle. The results showed that the mean flap survival area in group I (88.8 percent) was statistically higher than that in group II (62.6 percent, p < 0.001), and was higher in group IV (55.5 percent) than in group III (22.7 percent, p < 0.01). However, group II and group IV had no significant difference (p > 0.05). This experiment demonstrated that flap viability is determined by its intrinsic vascularization, both arterial and venous. The large superficial subcutaneous vein has a positive role (venous outflow) in proximally based flaps but a negative role (venous inflow) in distally based flaps. If the effect of the large subcutaneous vein is excluded, distally based flaps are not inherently inferior to proximally based flaps.     

Transient laminin beta 1a Induction Defines the Wound Epidermis during Zebrafish Fin Regeneration

The first critical stage in salamander or teleost appendage regeneration is creation of a specialized epidermis that instructs growth from underlying stump tissue. Here, we performed a forward genetic screen for mutations that impair this process in amputated zebrafish fins. Positional cloning and complementation assays identified a temperature-sensitive allele of the ECM component laminin beta 1a (lamb1a) that blocks fin regeneration. lamb1a, but not its paralog lamb1b, is sharply induced in a subset of epithelial cells after fin amputation, where it is required to establish and maintain a polarized basal epithelial cell layer. These events facilitate expression of the morphogenetic factors shha and lef1, basolateral positioning of phosphorylated Igf1r, patterning of new osteoblasts, and regeneration of bone. By contrast, lamb1a function is dispensable for juvenile body growth, homeostatic adult tissue maintenance, repair of split fins, or renewal of genetically ablated osteoblasts. fgf20a mutations or transgenic Fgf receptor inhibition disrupt lamb1a expression, linking a central growth factor to epithelial maturation during regeneration. Our findings reveal transient induction of lamb1a in epithelial cells as a key, growth factor-guided step in formation of a signaling-competent regeneration epidermis.     

The use of subcutaneous pedicle flaps in the treatment of postburn scar contractures

Subcutaneous pedicle flaps, which were usually applied to repair small skin defects in the face or the fingertip, have been used with success in the treatment of 17 postburn scar contractures, with the exception of one partial flap necrosis. The results indicate the reliability and usefulness of this technique in the treatment of scar contractures, even in the extremities or the trunk. Subcutaneous pedicle flaps are effective for relatively wide contractures or quadratic contractures. When the skin tension across the contracture line is too great to use any local flap, such as a Z-plasty or V-Y plasty, the subcutaneous pedicle flap is particularly useful, because it can be freely designed in an area where the tension is small. When the flap contains some superficial scarring, the subcutaneous pedicle flap is preferred over other local flaps because of the superior vascularity and mobility.     

The groin flap in reparative surgery of the hand

The historical literature of the use of axial vascular pattern flaps from the hypogastric and iliofemoral regions in reparative surgery of the hand is concisely reviewed. Thirty-six iliofemoral (groin) flaps were utilized for delayed primary resurfacing and secondary reconstruction of defects of the hand and forearm. Two flaps (6 percent) were complicated by partial necrosis. We caution against the immediate resurfacing (within 24 hours of injury) of acute crushed hand wounds by distant flaps. The immediate application of a healthy flap on a soiled or crushed wound invites complications of local tissue necrosis, infection, and subsequent loss of the flap. When distant flaps are indicated for coverage of acute hand wounds, delayed primary coverage following complete removal of all nonviable tissue is a safe and reliable regimen. It is advantageous to design the serviceable portion of the flap on the distal area of the vascular territory of the groin flap. Thoughtful yet "radical" defatting can be performed on the lateral portion of the groin flap territory. Constructed in this way, the long medial base of the groin flap allows freedom for movement at the wrist and metacarpophalangeal and interphalangeal joints, thus decreasing edema and stiffness. In the management of soft-tissue defects in the hand requiring distant flap coverage, we choose to utilize the conventional groin flap in preference to the microvascular free flap when both techniques will deliver equal results.     

The Saccharomyces cerevisiae Dna2 can function as a sole nuclease in the processing of Okazaki fragments in DNA replication

During DNA replication, synthesis of the lagging strand occurs in stretches termed Okazaki fragments. Before adjacent fragments are ligated, any flaps resulting from the displacement of the 5′ DNA end of the Okazaki fragment must be cleaved. Previously, Dna2 was implicated to function upstream of flap endonuclease 1 (Fen1 or Rad27) in the processing of long flaps bound by the replication protein A (RPA). Here we show that Dna2 efficiently cleaves long DNA flaps exactly at or directly adjacent to the base. A fraction of the flaps cleaved by Dna2 can be immediately ligated. When coupled with DNA replication, the flap processing activity of Dna2 leads to a nearly complete Okazaki fragment maturation at sub-nanomolar Dna2 concentrations. Our results indicate that a subsequent nucleolytic activity of Fen1 is not required in most cases. In contrast Dna2 is completely incapable to cleave short flaps. We show that also Dna2, like Fen1, interacts with proliferating cell nuclear antigen (PCNA). We propose a model where Dna2 alone is responsible for cleaving of RPA-bound long flaps, while Fen1 or exonuclease 1 (Exo1) cleave short flaps. Our results argue that Dna2 can function in a separate, rather than in a Fen1-dependent pathway.     

The versatile gastrocnemius myocutaneous flap.

The medial and lateral gastrocnemius myocutaneous flaps are described. Their usefulness, as direct flaps without a delay, in reconstruction of the lower extremity is described. In our practice, this flap has supplanted the cross-leg flap for most reconstructions in the lower extremity.     

The use of free revascularized grafts in the amelioration of hemifacial atrophy

Nine female and three male patients, 5 to 47 years old, were treated by free revascularized grafts for Romberg's disease. Greater omentum was transferred in nine, de-epithelialized skin flaps in three. Follow-up ranges from several months to 7 years. Microvascular failures or donor site complications did not occur. To further trim transferred tissue, overcome gravitational sag, or both, all but one patient required a secondary procedure. The only facial complication included partial loss of the transferred omentum and spotty necrosis of the overlying skin. The choice of omentum or de-epithelialized skin and subcutaneous fat is dictated by the extent of the facial defect. Generalized defects are corrected with omentum and localized segmental defects with de-epithelialized flaps. Because of observed late complications, including chronic inflammation, induration, and sinus tracts, we no longer recommend medical-grade liquid silicone as a therapeutic option in the palliation of Romberg's disease.     

The recovery of sensory function following skin flaps in humans

Two cross-sectional studies were made of the recovery of tactile and pain sensitivity in subjects having skin flaps in the region of the chest and neck as a result of tumor excision. In experiment 1, stimuli ranging from 2.46 to 17.10 gm of force were delivered by von Frey hairs to the flaps and comparable normal sites in 35 subjects at times ranging from 1 month to 10 years after surgery. No subjects perceived stimuli of less than 11.80 gm, thermal, or moving touch applied to flaps, whereas 21 percent perceived 11.80 gm or greater force (judged as painful applied to normal skin). The results of experiment 2 showed that these findings were not due to visual information available to subjects. Possible explanations for the fact that these results are radically different from those reported in the literature are discussed.     

Superiority of the deep circumflex iliac vessels as the supply for free groin flaps. Clinical work.

In this paper we present 16 cases of free transfer of compound flaps from the groin, 11 using the deep circumflex iliac vessels as a stem and 5 using the superficial circumflex iliac vessels as a stem. We found the deep vessels superior in many ways to the superficial vessels for this purpose; they are larger, permitting greater ease in anastomoses and providing more reliable blood flow. We believe that larger osteocutaneous or myocutaneous flaps can be transferred on the deep vessels than on the superficial ones-and that the deep circumflex iliac flap may supplant the conventional free going flap in most situations. The method evolved in response to patient need, not for surgical éclat.     

The S nipple-areola reconstruction

Nipple reconstruction is performed as a last stage in breast reconstruction following mastectomy. Various methods of nipple reconstruction have been described, most of them utilizing either free composite grafts or local flaps. The main problem encountered using either method is the gradual absorption and flattening of the nipple. The technique we used in reconstructing 22 nipples, in preference over the various methods accepted in breast reconstruction, achieves a long-standing, protruding nipple constructed from two large local flaps raised from an S-shape design. The technique is simple and permits freedom in choosing the height of the nipple, even in the presence of a mastectomy scar. The size of the nipple thereby constructed is in excess of what was expected. Shrinkage occurs during the first 2 months, and the resulting size is more than adequate. The areola is reconstructed by a full-thickness skin graft harvested from a nonhairy area of the upper inner thigh. The local flaps lack the necessary color, which is achieved by tattooing.     

Rate-determining Step of Flap Endonuclease 1 (FEN1) Reflects a Kinetic Bias against Long Flaps and Trinucleotide Repeat Sequences

Flap endonuclease 1 (FEN1) is a structure-specific nuclease responsible for removing 5′-flaps formed during Okazaki fragment maturation and long patch base excision repair. In this work, we use rapid quench flow techniques to examine the rates of 5′-flap removal on DNA substrates of varying length and sequence. Of particular interest are flaps containing trinucleotide repeats (TNR), which have been proposed to affect FEN1 activity and cause genetic instability. We report that FEN1 processes substrates containing flaps of 30 nucleotides or fewer at comparable single-turnover rates. However, for flaps longer than 30 nucleotides, FEN1 kinetically discriminates substrates based on flap length and flap sequence. In particular, FEN1 removes flaps containing TNR sequences at a rate slower than mixed sequence flaps of the same length. Furthermore, multiple-turnover kinetic analysis reveals that the rate-determining step of FEN1 switches as a function of flap length from product release to chemistry (or a step prior to chemistry). These results provide a kinetic perspective on the role of FEN1 in DNA replication and repair and contribute to our understanding of FEN1 in mediating genetic instability of TNR sequences.