PubMed Health⌕ Search

Biomedical subjects

M A Machado

Publications and source records attributed to M A Machado.

At least 37 records · Page 2Linked to original sources
PubMed2000

Hepatic adenoma and focal nodular hyperplasia: differential diagnosis and treatment.

The diagnosis of benign hepatic tumors as hepatic adenoma (HA) and focal nodular hyperplasia (FNH) remains a challenge for clinicians and surgeons. The importance of differentiating between these lesions is based on the fact that HA must be surgically resected and FNH can be only observed. A series of 23 female patients with benign liver tumors (13 FNH, 10 HA) were evaluated, and a radiologic diagnostic algorithm was employed with the aim of establishing preoperative criteria for the differential diagnosis. All patients were submitted to surgical biopsy or hepatic resection to confirm the diagnosis. Based only on clinical and laboratory data, distinction was not possible. According to the investigative algorithm, the diagnosis was correct in 82.6% of the cases; but even with the development of imaging methods, which were used in combination, the differentiation was not possible in four patients. For FNH cases scintigraphy presented a sensitivity of 38.4% and specificity of 100%, whereas for HA the sensitivity reached 60% and specificity 85.7%. Magnetic resonance imaging, employed when scintigraphic findings were not typical, presented sensitivities of 71.4% and 80% and specificities of 100% and 100% for FNH and HA, respectively. Preoperative diagnosis of FNH was possible in 10 of 13 (76.9%) patients and was confirmed by histology in all of them. In one case, FNH was misdiagnosed as HA. The diagnosis of HA was possible in 9 of 10 (90%) adenoma cases. Surgical biopsy remains the best method for the differential diagnosis between HA and FNH and must be performed in all doubtful cases. Surgical resection is the treatment of choice for all patients with adenoma and can be performed safely. With the evolution of imaging methods it seems that the preoperative diagnosis of FNH may be considered reliable, thereby avoiding unnecessary surgical resection.

Adenoma↗
PubMed2000

Platelet-derived growth factor/insulin-like growth factor-1 combination and bone regeneration around implants placed into extraction sockets: a histometric study in dogs.

This study evaluated, by histometric analysis, the wound healing process of bone around implants placed into extraction sockets with or without the concurrent application of a combination of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-1). Mandibular premolars were removed, and 32 implants were inserted in eight dogs. Before insertion, two implants received a single application of 5 micrograms/mL of PDGF and IGF-1 delivered in 0.10 mL of 4% methylcellulose gel or 0.10 mL of 4% methylcellulose gel only as a control. To label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, 15, 30, 45, 60, and 75 days after implant insertion. Three, 8, and 12 weeks after implant insertion, undecalcified sections were obtained, and the degree of bone contact with the implant surface, the bone area, and the intensity of bone labeling were measured into the limits of the threads of the implant. Greater extension of bone/implant contact (paired t test, P < .05) was observed in test (22.4% +/- 13.7%) than in control (17.2% +/- 13.6%) implants at 3 weeks. One-way ANOVA revealed a higher intensity of bone labeling (P < .05) at 3 weeks than at 12 weeks (127.8 +/- 42.59 and 56.7 +/- 26.34, gray scale values) for test implants. Within the limits of the present study, it was concluded that the combination of PDGF/IGF-I actively took part in the initial phase of bone repair.

Analysis of Variance↗
PubMed2000

Histometric evaluation of bone regeneration around immediate implants partially in contact with bone: a pilot study in dogs.

Bone regeneration was evaluated around immediate implants partially in contact with bone, with or without the concurrent application of a combination of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-1). Mandibular premolars were removed, and the implant osteotomies were prepared; a uniform circumferential gap was prepared 1.25 mm beyond the width of the implant bed in the coronal half. Twelve implants (8.5 x 3.75 mm) were inserted in six dogs. Before insertion, an implant received a single application of 5 micrograms/mL of PDGF and IGF-1 delivered in 0.10 mL of 4% methylcellulose gel or 0.10 mL of 4% methylcellulose gel only as a control. To label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, 15, 30, and 45 days after implant insertion Three and 8 weeks after implant insertion undecalcified sections were obtained, and the degree of bone to implant contact, the bone area, and the intensity of bone labeling were measured into the limits of the eight most coronal threads of the implant (four threads on each side of each implant). The results showed a greater extension of bone-to-implant contact, a larger percentage of bone area, and greater intensity of bone labeling for test versus control implants (P < .01). Within the limits of the present study, it was concluded that the combination of PDGF/IGF-1 might be an alternative for enhancing bone healing around implants partially in contact with bone.

Animals↗
PubMed2000

Alternative technique of laparoscopic hepaticojejunostomy for advanced pancreatic head cancer.

Only 20% of patients with pancreatic cancer can undergo curative resection. Therefore, palliative treatment of pancreatic cancer assumes the utmost clinical importance. The aim of the palliative treatment of pancreatic head carcinoma is to relieve the jaundice and/or duodenal obstruction. Endoscopic or transparietal decompression of the obstructed bile duct can be accomplished in most cases, but the durability of these techniques is not as great as that of a surgically created bypass. On the other hand, hepaticojejunostomy carries higher morbidity and mortality rates than the former nonsurgical methods. In order to promote long lasting palliation with low morbidity and mortality rates, minimally invasive techniques of biliary and gastric bypass have been described. However, laparoscopic Roux-en-Y hepaticojejunostomy seems to be a complex surgical procedure. With an aim to simplify the construction of a laparoscopic hepaticojejunostomy, the authors suggest an alternative technique.

Female↗
PubMed2000

Evaluation of guided bone regeneration and/or bone grafts in the treatment of ligature-induced peri-implantitis defects: a morphometric study in dogs.

The goal of this study was to evaluate, morphometrically, hard-tissue healing following the treatment of ligature-induced peri-implantitis defects in dogs and guided bone regeneration and/or bone grafts. Five dogs were used, and the mandibular premolars were removed. Three months later, two titanium implants were installed on each side of the mandible, and after another 3 months, abutment connection was performed. Following abutment connection, experimental periimplantitis was induced by placing cotton ligatures in a submarginal position. Ligatures and abutments were removed after 1 month and the bony defects were randomly assigned to one of the following treatments: debridement (DE), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG), and debridement plus guided bone regeneration associated with mineralized bone graft (GBR/BG). The dogs were euthanatized after 5 months. Morphometric analysis did not reveal significant differences among the treatments neither with respect to the percentage of bone to implant contact (p = 0.996) nor to the bone area (p = 0.946) within the limits of the threads of the implant. Within the limits of this investigation, there is insufficient evidence to indicate that any of the treatments presented an improved response in dealing with bony defects resulting from peri-implantitis.

Alveolar Bone Loss↗
PubMed2000

Hereditary gingival fibromatosis: report of three cases.

Three cases of generalized and severe HGF in young patients of the same family without other features are reported. The purpose of this article is to present documented cases and discuss the identification, treatment, and control of the disease. The histopathological characteristics of HGF are emphasized.

Child↗
PubMed2000

The influence of nicotine on the bone loss rate in ligature-induced periodontitis. A histometric study in rats.

BACKGROUND: The present study investigated the possible influence of nicotine on the bone loss rate in the furcation region due to ligature-induced periodontitis in rats. METHODS: Twenty adult male Wistar rats were included. After anesthesia, the tooth was randomly assigned to receive the cotton ligature in the sulcular area, while the contralateral tooth was left unligated. The animals were randomly assigned to one of the following treatments, including daily intraperitoneal injections: group A, 2 microl/g body weight of saline solution; group B, 2 microl/g body weight of a nicotine solution with 0.13 microl of nicotine/ml of saline solution; group C, 2 microl/g body weight of a nicotine solution with 0.19 microl of nicotine/ml of saline solution; and group D, 2 microl/g body weight of a nicotine solution with 0.26 microl of nicotine/ml of saline solution. Thirty days later, the animals were sacrificed and the specimens routinely processed for serial decalcified sections. RESULTS: Intergroup analysis revealed greater bone loss in the ligated teeth of group B (1.01 +/- 0.61 mm2), group C (1.14 +/- 0.72 mm2), and group D (1.36 +/- 0.60 mm2) when compared with group A (0.64 +/- 0.62 mm2) (P <0.01). However, no statistically significant differences in bone loss were found among groups B, C, and D. In addition, no bone loss was observed for unligated teeth (P>0.01). CONCLUSIONS: Within the limits of the present study, nicotine enhanced the effects of the local components of periodontal disease in a non-dose-dependent way; nevertheless, the administration of nicotine did not produce periodontal bone loss by itself.

Alveolar Bone Loss↗
PubMed2000

Treatment of ligature-induced peri-implantitis defects by regenerative procedures. Part II: A histometric study in dogs.

The purpose of this study was to evaluate, by histometric analysis, re-osseointegration following treatment of ligature-induced peri-implantitis in dogs. Five dogs were used in this study. Their mandibular premolars (P2, P3 and P4) were first removed. After 3 additional months of healing, two titanium implants were placed on each side of the mandible. After 3 months, the abutment connection was performed and experimental peri-implantitis was induced by placing cotton ligatures in a submarginal position. Ligatures and abutments were removed after one month and the peri-implant bone defects were randomly assigned to one of the treatments: debridement, debridement plus guided-bone regeneration, debridement plus mineralized-bone graft, and debridement plus guided-bone regeneration associated with mineralized-bone graft. Five months post-treatment, the degree of bone contact with the implant surface and the bone area within the threads were measured in 12 threads, the 6 most coronal at each side of each implant. One-way analysis of variance did not reveal statistically significant differences between the treatment modalities (p > 0.05). Within the limits of the present study, it can be concluded that there is a limited possibility of re-osseointegration around implant surfaces previously exposed by ligature-induced peri-implantitis.

Analysis of Variance↗
PubMed1999

Treatment of ligature-induced peri-implantitis defects by regenerative procedures: a clinical study in dogs.

We carried out a clinical evaluation of the hard tissue fill following treatment of ligature-induced peri-implantitis in dogs. Four dogs were used and their mandibular premolars (P2, P3 and P4) were removed. After 3 months of healing, two titanium implants were placed on each side of the mandible. After 3 months, the abutment connection was performed, and experimental peri-implantitis was induced by placement of cotton ligatures in a submarginal position. The ligatures and abutments were removed after one month, and the peri-implant bone defects were assigned randomly to one of the treatments: debridement (control), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG), and debridement plus guided bone regeneration associated with a mineralized bone graft (GBR + BG). Clinical measurements of the peri-implant bone defects before and 5 months after treatment revealed no statistically significant differences between the defects treated by GBR, BG and GBR + BG. These 3 treatment methods provided more hard tissue fill than debridement alone (p < 0.05). Thus, it can be concluded that GBR, BG or a combination of the two techniques can enhance the hard tissue fill in defects caused by peri-implantitis in dogs.

Analysis of Variance↗
PubMed1999

Primary intrahepatic lithiasis: report of a case treated by laparoscopic bilioenteric anastomosis.

Recent advances in videolaparoscopic surgery have made this method the treatment of choice for many biliary diseases. However, it has not been used in certain cases, such as primary intrahepatic lithiasis. The authors report a case of a 62-year-old woman with a history of several episodes of cholangitis. Investigation revealed dilated intra- and extrahepatic bile ducts with intrahepatic stones. The patient underwent laparoscopy, and intraoperative cholangiography disclosed an enlarged common duct with absence of stones and the presence of multiple calculi in the intrahepatic biliary tree. A choledochotomy followed by choledochoscopy was performed, which revealed several intrahepatic pigmented stones that were completely retrieved, followed by a laterolateral choledochoduodenostomy to decompress the biliary tree and to allow the migration of residual or recurrent stones. The patient had an uneventful recovery and was discharged on the fourth postoperative day. After 15 months of follow-up the patient is asymptomatic with normal results of liver function tests. Late postoperative upper digestive endoscopy showed a patent choledochoduodenostomy.

Bile Ducts, Intrahepatic↗
PubMed1998

Cloning, characterization, and chromosomal assignment of the human ortholog of murine Zfp-37, a candidate gene for Nager syndrome.

In an effort to identify putative transcription factors involved in chondrocyte differentiation during human endochondral bone formation, a human fetal cartilage-specific cDNA library was screened with a degenerate oligonucleotide probe corresponding to a conserved stretch of eight amino acids from the zinc finger region of the Drosophila Krüppel gene family of DNA-binding proteins. Using this strategy, we have identified a novel zinc finger gene ZFP-37. ZFP-37 corresponds to a putative transcription factor containing 12 tandemly repeated zinc finger motifs and a Krüppel-associated box (KRAB) domain. The KRAB domain has been reported to function as a transcriptional repressor and is located in the amino terminus, while the zinc finger repeats are positioned at the carboxy-terminal end of ZFP-37. Gene mapping with a somatic cell hybrid panel and fluorescence in situ hybridization (FISH) localized ZFP-37 to human Chr 9q32. The gene is expressed at low level as a 3.2-kb mRNA in several tissues including fetal human cartilage. Sequence comparison revealed that ZFP-37 may represent the human homolog of the mouse gene Zfp-37. The map location and expression pattern suggest ZFP-37 as a candidate gene for a craniofacial-limb malformation, Nager syndrome (acrofacial dysostosis).

Amino Acid Sequence↗
PubMed1998

An alternative technique in the treatment of celiac axis stenosis diagnosed during pancreaticoduodenectomy.

Celiac compression is usually a benign condition, but when surgery necessitates division of collaterals from the superior mesenteric artery, it may cause life-threatening celiac organ ischemia. Celiac axis obstruction is found in 12.5% to 49.7% of patients during abdominal angiography. In such patients, the arterial blood supply to the stomach, spleen, and liver is sustained through extraordinarily well-developed pathways in the pancreas. Though collateral pathways may be sacrificed during pancreaticoduodenectomy, only a small proportion of patients develop hepatic, gastric and splenic ischemia during the procedure. If the appropriate angiographic studies have not been obtained before pancreatic resection, a test occlusion of the gastroduodenal artery, as recommended by Bull et al., should precede its ligation. The hepatic arteries are palpated before and after the test occlusion. In the occasional patient in whom the pulse diminishes during occlusion or if there is evidence of upper abdominal visceral ischemia, revascularization of the celiac circulation may be required. Reestablishment of the celiac circulation may be accomplished by the use of a vein graft between the aorta and the celiac tributaries. This article describes an alternative technique for revascularization of the celiac circulation without the use of a venous graft.

Anastomosis, Surgical↗
PubMed1997

Large-volume leukaphereses may be more efficient than standard-volume leukaphereses for collection of peripheral blood progenitor cells.

To overcome the need for multiple leukaphereses to collect enough PBPC for autologous transplantation, large-volume leukaphereses (LVL) are used to process multiple blood volumes per session. We compared the efficiency of CD34+ cell collection by LVL (n = 63; median blood volumes processed 11.1) with that of standard-volume leukaphereses (SVL) (n = 38; median blood volumes processed 1.9). To achieve this in patients with different peripheral blood concentrations of CD34+ cells, we analyzed the ratio of CD34+ cells collected per unit of blood volume processed, divided by the number of CD34+ cells in total blood volume at the beginning of apheresis. For LVL, 30% (9%-323%) of circulating CD34+ cells were collected per blood volume compared with 42% (7%-144%) for SVL (p = 0.02). However, in LVL patients, peripheral blood CD34+ cells/L decreased a median of 54% during LVL (similar data for SVL not available). The number of CD34+ cells collected per blood volume processed after 4 and 8 blood volumes and at the end of LVL were 0.32 (0.01-2.05), 0.24 (0.01-1.68), and 0.22 (0.01-2.40) x 10(6) CD34+ cells/kg, respectively (p = 0.0007), despite the 54% decrease in peripheral blood CD34+ cells/L throughout LVL. A median 66% decrease in the platelet count was also observed during LVL. Thus, LVL may be more efficient than SVL for PBPC collection, allowing, in most patients, the collection in one LVL of sufficient PBPC to support autologous transplantation.

Adult↗
PubMed1996

Autotransfusion with laparoscopically salvaged blood in trauma: report on 21 cases.

Autotransfusion is being increasingly used to avoid the complications of homologous blood transfusion. In abdominal trauma, however, the collected blood may be contaminated by intestinal contents when digestive or urinary lesions are present. In such situations, the reinfusion of blood is contraindicated. We present our experience with autotransfusion of blood collected by laparoscopy from the abdominal cavity of 21 trauma patients. Laparoscopy allowed the aspiration of blood and, at the same time, permitted diagnosis of visceral lesions, avoiding reinfusion of contaminated blood. No complications occurred, and hematocrit values were significantly elevated. This procedure may represent the only possible method of blood transfusion in Jehovah's Witnesses, as with one patient in our series.

Abdominal Injuries↗
PubMed1994

An unusual case of four iliac veins injured by gunshot: case report and review of the literature.

Multiple injuries of iliac veins are uncommon and frequently fatal. An unusual case in which there were injuries of the four iliac veins by gunshot is described. Prompt control of hemorrhage is required. Because our patient was in unstable condition, ligation of the four iliac veins was performed and the abdomen was packed. After a complicated course, the patient was discharged after 40 days in good condition. Although venous repair is often recommended, ligation in extensive injuries may be necessary, and is usually well tolerated in young, previously healthy individuals like our patient.

Abdominal Injuries↗