Eduardo Wei Kin Chin

Surgical reduction of the renal mass in rats: morphologic and functional analysis on the remnant kidney

PURPOSE This study has analyzed the biochemical and morphological effects on the remnant kidney in rats which were submitted to progressive surgical ablation of renal mass. METHODS Sixty Wistar male rats, weighing between 210 and 380g, were used and they were distributed in 3 groups of 20 animals each. The rats from the groups called 1, 2 and 3 were submitted to the surgical removal of renal tissue equivalent to 1/2, 2/3 and 5/6 of the whole renal mass, respectively. Then the groups were subdivided into 2 subgroups and they were operated again within 24 hours (subgroups 1B, 2B and 3B) and within 8 weeks (subgroups 1C, 2C and 3C) for the removal of the remnant kidney. 24-hour urine and blood were collected to analyze serum creatinine, clearance of creatinine and proteinuria in the first surgical intervention and at the time of the re-operation. The remnant kidney was submitted to a macroscopic evaluation for the degree of hypertrophy and to the analysis of histology. RESULTS There was a significant increase of the volume of the remnant kidney (164%) and glomerular sclerosis was present in 40% of the animals submitted to the ablation of 5/6 of renal mass. Functional alterations characterized by the increase of urinary excretion of proteins (50% in group 3), rise in the serum creatinine (261% subgroup 2B; 371% subgroup 3B, 118% subgroup 3C) and a significant reduction of the clearance of creatinine (control x subgroup 3C = 2,88 x 1,15 ml/min: p<0,05 were also observed. CONCLUSION The compensatory renal hypertrophy, as well as the glomerular injury translated in the form of proteinuria and sclerosis, are closed related to the volume of the remnant kidney, thus they are more evident when a greater fraction of the renal tissue is excised.

Estudo morfométrico e morfológico da cicatrização após uso do laser erbium: YAG em tecidos cutâneos de ratos

This study analyses the skin contracture effect of the erbium:YAG (Er:YAG) laser on the skin of rats by light microscopic histological and morphometrical evaluations. Two squares of back skin were precision tattooed on each of the animals (n = 35), that were termed control and experimental skin. The experimental skin was treated with three passes of the Er:YAG laser with standardized parameters. Five animals were killed and skin specimens were analyzed at 00, 07, 14, 28, 56, 84 and 112 days. Histologic examination demonstrated a mean of 215.24 micrometers ablative damage that was homogeneous with complete vaporization of the epidermis and superficial dermis. The residual thermal damage was small (mean of 41.45 micrometers) observing areas where it was absent. The cicatritial fibroplasy was present at day 07 (mean 55.58 micrometers) rising quickly until day 28 (mean of 209.49 micrometers) when it reaches a plateau and maintaining it until day 112. There are no signs of acute inflammatory process at day 07 and the reepithealization was complete at this day. This study revealed that the laser had induced shortening of the treated areas which persisted beyond the 112 days.

Laparoscopic partial nephrectomy in rats

PURPOSE To establish an experimental model of laparoscopic partial nephrectomy (LPN) in rats and to analyze morphological alterations in the renal parenchyma utilizing an electric cautery and harmonic scalpel. METHODS Forty Wistar rats were used, divided in 2 experiments with 20 rats each: experiment I, LPN was performed with an electric cautery and the rats were subdivided into groups A and B; experiment II, LPN was performed with a harmonic scalpel and they were subdivided into groups C and D. The animals in groups A and C were sacrificed shortly after surgery and the remnant kidney was removed to study the following variables: necroses and degeneration. In groups B and D a laparatomy was performed for retrieval of the remnant kidney on the 14th day after surgery to analyze fibrous scarring. RESULTS For the variables necroses and fibrous scarring, the electric cautery creates, on average, greater width than that produced by the harmonic scalpel (p=0.0002 and p=0.0068 respectively). Regarding the variable of degeneration, we found no significant difference between the two types of scalpels (p=0.1267). CONCLUSIONS LPN in rats is an adequate and feasible experimental model. The electric cautery caused greater damage to remnant renal tissue when compared to harmonic scalpel.

Retalho de submucosa de intestino delgado autólogo para aumento da capacidade da bexiga: estudo experimental em cães

BACKGROUND: Many materials, including organic and synthetic prosthesis, have been described as substitutes of the genitourinary tract. The most commonly used is the ileum, which has many advantages, as easy mobilization and regular vascular pattern. However, the ideal substitute for urinary tract has not been found yet. Ileocystoplasty is not a harmless procedure, and so, investigations are constantly being made to find new substitutes. Small intestinal submucosa (SIS) is an extracelular matrix that can be used as a reabsorbable scaffold for tissue engineering. It allows blood vessels ingrowth, epithelial and connective cells proliferation, induces growing factors production and acquires macro and microscopic characteristics similar to the native tissue. In the urinary tract, previous experimental studies have demonstrated that SIS promotes bladder regeneration. The aim of the present study was to evaluate the biocompatibility of an autologous SIS implant used for bladder augmentation. METHOD: Eight mongrel dogs, weighing between 8 and 15 kg, were prepared for surgery under general anesthesia. A 3cm full-thickness midline cystotomy was performed, followed by immediate augmentation with autologous small intestine submucosa patch graft. On the 30th post-operative day, the animals were re-operated and a fragment of the urinary bladder wall including its patch was removed for histopathogical study. RESULTS: All implants were well incorporated. Macroscopically, SIS could not be distinguished from the native bladder tissue. Mild adherences occurred on the anterior parietal peritoneum. No other macroscopic complications were found. Acute inflammatory response was absent, and chronic inflammatory cells were seen in mild degree. Foreign body reaction was not present, implying satisfactory biological acceptation of the SIS patch graft. Epithelialization was complete in 7/8 implants. Fibroblastic proliferation was moderate. The densitometry of collagen revealed a greater amount of collagen III. Submucosa patch absorption was moderate in most cases. CONCLUSION: We concluded that autologous small intestine submucosa promotes bladder tissue regeneration. Small intestinal submucosa can represent a new option in urinary tract reconstruction.

Influência do buflomedil em retalhos cutâneos isquêmicos: estudo experimental em ratos

Vasoactive drugs have been employed in an attempt to increase the viability of ischemic skin flaps. The aim of the present study was to evaluate the effects of the vasoactive drug, Buflomedil, in the prevention of ischemic skin flaps of rats. Twenty male rats were divided into na experimental group B and a control group A. In the animals of group B, 3mg/kg of Buflomedil was given intraperitoneally every 12 hours for 2 days before surgery and for 7 days after surgery. An abdominal skin flap was used as a model, with a cephalic base measuring 9 x 4cm. The viability of the flaps was evaluated with a laser fluxometer in predetermined points in the early pre and postoperative period and on the 7th post operative day Planimetric analysis of the total area of the flap, of the vascularized area, and of the necrotic area were done on the 7th day after the operation. Inferior necrosis of the flap was observed in all of the animals in both groups. The statistical analysis of the results obtained did not show a significant difference in the planimetry between the control and the experimental groups. Fluxometry did not show a significant difference in relation to the median points between the two groups. It was concluded that Buflomedil, in the manner in which it was used in this experiment, does not reduce necrosis in ischemic skin flaps of rats.

Histopathologic and morphometric evaluation of the skin abnormalities induced by erbium:YAG and carbon dioxide lasers in 10 patients.

In the 1960s, carbon dioxide (CO2) laser therapy started to be applied to eliminate wrinkles, actinic scars, and acne because of its capacity of induce intracellular water vaporization. However, recent studies have shown the efficacy of the erbium laser in removing delicate and moderate scars. Furthermore, the postoperative lesions induced by the erbium laser seem to resolve faster and with less erythematous pattern compared with lesions induced by the CO2 laser. The purpose of this study was to determine the immediate pathologic alterations caused by single applications of CO2 and erbium lasers and their association in human skin shreds. Ten white female patients aged 30 to 63 years underwent rhytidectomy, and their respective shreds, which were prepared for excision, were tattooed with the CO2 laser, the erbium laser, or a combination of both in random order and number of applications, before final removal. This project was approved by the local ethical committee. After surgical removal, these tattooed shreds were fixed in 10% buffered formalin and submitted to histopathologic analysis. Morphometric studies demonstrated the normal skin thickness and thickness of the laser-treated area, and their subtraction resulted in the ablation damage values. Residual thermal damage corresponded to the thickness of the affected skin from the most superficial layer of tissue in the laser-treated area down to the deepest dermal area with basophilic degeneration of collagen fibers. Our results showed that two CO2 applications resulted in greater ablation and residual thermal damage when compared with only one CO2 application. The same was true in comparisons of one and two applications of the erbium laser. Both results were statistically significant (p < 0.05). When one isolated erbium and one isolated CO2 application were compared, ablation damage was greater in the former group, although with no statistical significance. One CO2 plus one erbium application compared with one isolated CO2 application showed similar ablation damage but greater residual thermal damage in the latter group (p < 0.05). These observations might contribute to our understanding of the lesions caused in the human skin by erbium and CO2 lasers and eventually help determine the ideal laser combination for the appropriate surgical treatment.

Cicatrização de anastomoses do cólon esquerdo com doença inflamatória: estudo experimental em ratos

Complications related to anastomosis failure are frequently described in the surgery of inflammatory bowel disease. The aim of the present study was to evaluated colonic wound healing in an inflamed bowel. Forty Wistar rats were divided in 2 groups: the control and experimental groups. In the experimental group, colitis was induced by the infusion of 10% acetic acid per rectum to understand how inflammation interferes with the healing process of intestinal. On the7th post-operative day an end to end colonic anastomosis was performed with interrupted suture. On the 3rd and 7th post-operative days, the anastomosis were evaluated. We observed that mortality and the number of complications were greater in the group of animals with inflammatory bowel disease. Dehiscence with peritonitis was the most common complication(p=0.0222). The bursting strength in the colons without leakage was lesser than those in the control group, however this difference was not statistically significant (p=0,0836). It was verified that the anastomosis performed in colons with inflammatory bowel disease showed greater total collagen concentration, with a predominance of immature collagen (type III) (p=0.0000). The mature collagen (type I) was the predominant collagen in the wounds of normal colon. (p=0.0102). On the 3th post-operative day It was also observed that the organization of collagen was poorer on the third day in the colonic wounds with inflammatory bowel disease. Nevertheless, the analysis of the inflammatory reaction at the level of the anastomosis was similar in both groups. These results suggest that inflammatory bowel disease increases the risks of anastomosis dehiscence, probably because of the delay in the maturation and the organisation of collagen.

Influência do tempo transcorrido entre a lesão do cólon e a síntese no processo de cicatrização

The treatment of colonic lesions has been modified regarding the choice of primary repair technique, colostomy and secondary repair. Among risk factors for primary repair is time lapse. The aim of the present study was to evaluate the role of the time span between the induced lesion and surgical repair, regarding wound healing. Eighty PUC-PR Wistar rats were used for this purpose. Under ether anesthesia a lesion in the left colon was made, affecting 50% of the circumference of the intestine. After 12, 18 and 24 hours the repair was done. The colonic repairs were compared to the those made immediately after the lesion. Wounds were evaluated on the 4th and 7th post-operative days and the repair was evaluated regarding the presence of leakage and abscess were evaluated. The breaking strength and the collagen synthesis were also analysed. Five rats died. In the experimental groups, peritonitis was observed and when compared to the control group a high statistically significant difference was demonstrated (for group B p=0.0018, for group (p=0.0033 and for D p=0.000008). In 19 animals, dehiscence was present and was statistically significant in the 24 hours group (p=0.000002). The amount of mature collagen (type I) on the 4th day was similar to the control group of 12 and 18 hours and lesser in the 24 hour group (p<0.05). On the 7th day it was lesser in the 18 hour group (p<0.05) and in the 24 hour group (p=0.00001). There was a lesser concentration of immature collagen (type III) in the 24 hour group on the 4th day (p=0.000268) and on the 7th day in the groups of 18 hours (p=0.0009) and of 24 hours (p=0.000009). It may be concluded that delayed repair, longer than 12 hours increases morbidity and delay collagen deposition.maturation.

Análises morfométrica e morfológica das alterações cutâneas após uso do laser Nd-YAG em tecidos palpebrais humanos

The use of laser Neodymium-Yttrium-Aluminium-Garnet (Nd-YAG) as an auxiliary tool on rejuvenation provided a refining of the traditional technique. This laser procedure show satisfactory results with technical improvement and postoperatory recovery. OBJECTIVES: The aim of this study is to show the histological and morphometrical changes found in human eyelid tissue after the use of laser Nd-YAG and its comparision to the normal structure. MATERIAL AND METHODS: Nine female patients underwent laser Nd-YAG application on their right eyelid. The left eyelid was taken by control-tissue, free of any kind of procedure. It was made many applications of the laser and on the last day, it was made a bilateral biopsy. The morphometrical criteria appraised were: epidermal denseness measure, subepidermal area free of injury, colagen degeneration and total dermal density. RESULTS: In those areas whose underwent laser the epidermal measure was of 33,53 micrometers (µm) and on the normal tissue, was of 29.61µm (p = 0.1099). The subepidermal measure was, on average, of 40.93µm on right side and of 36.27µm on left side (p = 0.1373). The colagen degeneration measure on the right side was of 293.54µm and on the left side was of 292.22µm (p = 0.4835). On the procedure site, the total dermal measure was of 681,48µm and on the free site, it was of 664.14µm (p = 0.3492). DISCUSSION AND CONCLUSIONS: Despite the clinical changes observed after laser Nd-YAG therapy, there were neither histological nor morphometrical significative changes.

O papel do tamanho dos poros na biocompatibilidade de duas próteses de polipropileno usadas na retopexia pré-sacra estudo experimental em cães

Rectal prolapse is a socially disabling condition afflicting both the young and old individuals. Among the most used surgical procedures are the rectopexies with polypropylene meshes. To compare the biological behavior of two polypropylene, macroporous and monofilament meshes, of different pore size and manufactured with different structural configurations, when fixed on the pre-sacral fascia. Prolene® mesh, a woven mesh with pore size of 164 x 96µ; and T mesh, a non-woven experimental test mesh, with pore size of 4 x 3 mm and pore area 762 times larger than that of Prolene®. Eighteen mongrel dogs, weighing between 8 and 15 kg, were divided in two groups: Prolene® mesh (n=9) and T mesh (n=9). A 4,5 x 2 cm patch of mesh was used to perform the pre-sacral rectopexy by placing nonabsorbable sutures. On the 30th post-operative day, the animals were re-operated and a fragment of the rectal wall including its mesh patch was removed. The macroscopic study evaluated the presence of seroma, hematoma, abscess, fistula, stricture, adhesions and the degree of incorporation of the mesh. The microscopic analysis estimated the inflammatory reaction, foreign body reaction, fibroblastic penetration and the collagen densitometry. One dog of the Prolene® mesh group developed seroma and the mesh was not incorporated. Adhesions were present in all dogs. The other macroscopic parameters were absent in both groups. The microscopic analysis showed lesser inflammatory reaction and higher migration of fibroblasts, attesting the favorable incorporation of the prosthesis. Low foreign body reaction was present, implying satisfactory biological acceptation of the prosthetic material. The densitometry of collagen revealed that the T mesh, with pore area 762 x larger than that of the Prolene® mesh, incorporated a greater amount of total collagen. Whereas the amount of type III or immature collagen was similar in both meshes, the type I or mature collagen was greater in T mesh group. There was no difference between the two groups in macroscopic and histologic studies. Both meshes presented successful incorporation and good biological acceptation. There was a significantly greater incorporation of total collagen and type I (mature) collagen in the T mesh.