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Biomedical subjects

T G Wilson

Publications and source records attributed to T G Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1994

Advances in the use of guided tissue regeneration for localized ridge augmentation in combination with dental implants.

Osseointegrated dental implants placed into adequate bone enjoy a high success rate. However, placing implants into resorbed alveolar ridges can result in fixtures that are not optimally positioned or must be placed in insufficient bone, thus reducing their rate of success. Recently, techniques for bone regeneration developed for use around teeth have been applied to implant dentistry. Guided Tissue Regeneration (GTR), also called Guided Bone Regeneration (GBR), uses thin membranes which act as barriers to soft tissue ingrowth. This approach for regenerating bone around implants is described in detail in this paper. Initial approaches and modifications are covered as are specific details of current techniques.

Alveolar Bone Loss↗
PubMed1993

Urological evaluation and management of renal-proximity stab wounds.

The urological evaluation and management of renal-proximity stab wounds remain controversial. Questions regarding the "best" first radiographic study and the indications for nonoperative management are still unanswered. At the Los Angeles County-University of Southern California Medical Center we retrospectively reviewed the charts of 244 patients evaluated between January 1985 and December 1990 for renal-proximity stab wounds. There were 184 patients who presented without hematuria, 46 who presented with microscopic hematuria and 14 who presented with gross hematuria. When used as the first diagnostic study, an excretory urogram was 96% accurate in establishing the presence or absence of injury. In 34 patients additional evaluation was done with computerized tomography and/or angiography. A total of 43 injuries (17.6%) was found, of which 27 were successfully managed nonoperatively and 16 were managed surgically (1 nephrectomy). One patient had significant postoperative hemorrhage after partial nephrectomy, which was successfully managed with angiographic embolization. We conclude that although the degree of hematuria was a good indication of renal injury, the absence of hematuria did not preclude injury. In addition, excretory urography appears to be an acceptably reliable first study at our institution. We advocate a renal angiogram as the second radiographic study of choice because it reliably stages significant injuries and offers the possibility of therapeutic transcatheter embolization. Most renal injuries, when accurately staged, can safely be managed nonoperatively.

Adolescent↗
PubMed1993

Transposable elements as initiators of insecticide resistance.

Genetic change that leads to insecticide resistance is poorly understood for most resistance genes. Transposable elements have been shown to be powerful mutagenic agents in Drosophila melanogaster (Meigen), and they potentially can create genetic change leading to resistance in pest insect populations. Here the characteristic of transposable elements and the consequences of their movement in D. melanogaster and other insects are discussed, and reports of their involvement in insecticide resistance are examined. I conclude that transposable elements must be considered as mutagenic agents that can lead to resistance. Their involvement needs to be directly addressed in studies of resistant insects, particularly by investigators involved in cloning resistance genes.

Animals↗
PubMed1993

Laparoscopic cholecystectomy for acute inflammation of the gallbladder.

OBJECTIVE: The aim of this study was to prospectively assess the results of laparoscopic cholecystectomy in patients with acute inflammation of the gallbladder. SUMMARY BACKGROUND DATA: Laparoscopic cholecystectomy has become the standard treatment for symptomatic gallbladder disease. Its role in the surgical treatment of acute cholecystitis has not been defined, although a number of recent reports suggest that there should be few contraindications to an initial laparoscopic approach. METHODS: All patients presenting with symptomatic cholelithiasis from October 1990 until June 1992 were evaluated at laparoscopy with intention of proceeding to a laparoscopic cholecystectomy. The gross appearance of the gallbladder was categorized as acute inflammation, chronic inflammation, or no inflammation. Ninety-eight (23.4%) of 418 patients had acute inflammation of the gallbladder: 55 were edematous, 10 were gangrenous, 15 had a mucocele, and 18 had an empyema. RESULTS: The authors assessed outcome in these patients. The frequency of conversion to an open operation was 33.7% for acute inflammation, 21.7% for chronic inflammation (p < 0.05), and 4% for no inflammation (p < 0.001). The conversion rate was highest for empyema (83.3%) and gangrenous cholecystitis (50%), while the conversion rate for edematous cholecystitis was 21.8% and for acute inflammation with a mucocele it was 7%. The median operation time for successful laparoscopic cholecystectomy for acute inflammation was 105 minutes, which was longer than that with no inflammation (90 minutes). However, the incidence of complications was not different from that for chronic or no inflammation. The median postoperative stay for patients with acute gallbladder inflammation was 2 days for successful laparoscopic cholecystectomy and 7 days for patients converted to an open operation. CONCLUSIONS: Laparoscopic cholecystectomy for acute inflammation of the gallbladder is safe and is associated with a significantly shorter postoperative stay compared to open surgery. A greater number of patients required conversion to open operation compared to those with no obvious inflammation. Conversion to open operation was most frequent for empyema and gangrenous cholecystitis, suggesting that once this diagnosis is made, excessive time should not be spent in laparoscopic trial dissection before converting to an open operation.

Acute Disease↗
PubMed1993

Laparoscopic appendicectomy: a prospective analysis.

The potential advantages of laparoscopic surgery for a number of abdominal operations including appendicectomy have been heralded. In this study the aims were to assess prospectively the role of routine diagnostic laparoscopy in the diagnosis of acute appendicitis and determine the efficacy of laparoscopic appendicectomy. Patients with suspected acute appendicitis had diagnostic laparoscopy. When the diagnosis was confirmed laparoscopic appendicectomy was performed. Where an alternative diagnosis was made the appropriate treatment was instituted. If no diagnosis could be made the macroscopically normal appendix was removed by laparoscopic appendicectomy. Eighty-one patients (50 female, 31 male) had an initial diagnostic laparoscopy; 53 had appendicitis and proceeded to laparoscopic appendicectomy. A diagnosis could not be established at diagnostic laparoscopy in six patients and they also proceeded to laparoscopic appendicectomy. An alternative diagnosis was made in the remaining 22 patients (19 female and 3 male), with five proceeding to laparotomy and one patient with mesenteric adenitis having laparoscopic appendicectomy. Seven patients having laparoscopic appendicectomy required conversion to an open operation due to a retrocaecal or perforated appendix. The median operating time for successful laparoscopic appendicectomy was 55 min (range 30-95). Morbidity occurred in five of 53 patients having a successful laparoscopic appendicectomy. The median postoperative hospital stay was 2 days. The median time before return to normal activities was 8 days. Diagnostic laparoscopy is a useful diagnostic technique in women with suspected acute appendicitis, as it improves diagnostic accuracy, reduces the negative appendicectomy rate and avoids unnecessary laparotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Laparoscopic cholecystectomy and management of choledocholithiasis.

The advent of laparoscopic cholecystectomy (LC) has led to a reassessment of the approach to the management of choledocholithiasis. In a consecutive series of 418 patients undergoing LC, common bile duct (CBD) stones were suspected pre-operatively in 130 patients. Forty-five of the patients (35%) were found to have CBD stones on either pre-operative endoscopic retrograde cholangiopancreatography (ERCP; 20) or on operative cholangiography (OC; 25). Common bile duct stones were detected on OC in a further 12 of 288 patients (4.2%) without pre-operative suspicion of choledocholithiasis. Of the total of 57 patients with CBD stones, the duct was cleared by pre-operative ERCP and endoscopic sphincterotomy (ES) in 15 patients. In 13 patients, two of whom had had a pre-operative ERCP and ES, duct clearance was achieved by relaxing the sphincter pharmacologically and flushing the CBD via the OC catheter. One patient had an on-table ERCP and ES with successful stone extraction during LC. Eleven patients were converted to open operation with bile duct exploration. Sixteen patients had a postoperative ERCP. In five patients the CBD stones had passed spontaneously in the time between LC and ERCP. Ten patients required ES to clear the duct of stones. One patient had a failed ERCP and is still awaiting a repeat. The remaining patient was scheduled, but did not return for follow-up ERCP. In summary, pre-operative ERCP was indicated in less than 10% of patients in this series.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Subcutaneous metastases after laparoscopic resection of malignancy.

Following the introduction and widespread acceptance of laparoscopic cholecystectomy, laparoscopic techniques have been applied to an increasing variety of general surgical procedures. Recently, laparoscopic procedures for resection of malignancy have begun to emerge, in particular laparoscopic assisted colectomy for carcinoma of the colon. In the cases reported here, metastatic tumour in the laparoscopy port sites is described as a potentially serious complication of laparoscopic procedures for resection of malignancy.

Abdominal Neoplasms↗
PubMed1993

The results of efforts to improve compliance with supportive periodontal treatment in a private practice.

Patients who receive routine supportive periodontal treatment (SPT) tend to keep their teeth longer and enjoy greater periodontal health than those individual who do not receive this therapy. Previous studies have found less than optimal compliance to suggested SPT. The study reported in this paper covered 5 years of patient data and measured the effects of efforts to improve compliance in a private periodontal practice. These efforts included attempts at simplifying compliance, maintaining records of compliance, informing patients of the consequences of noncompliance, and attempting to identify noncompliers before active periodontal therapy was initiated. The results were measured against a similar group studied in previous work within the same office published in 1984. The main finding of the present study was an increase in complete compliance from 16% in 1984 to 32% in 1991. This increase came largely at the expense of the noncompliant group. The reason for the increase in compliance is likely due to efforts to increase compliance carried out in the office. However, other factors such as change in the hygiene practice law, increased public awareness of dental needs, and economic depression may also have affected compliance. This information suggests that noncompliance can be reduced if the problem is recognized and efforts are made to increase compliance.

Adolescent↗
PubMed1993

The current status of determining periodontal prognosis.

Determining the prognosis for patients and individual sites with inflammatory periodontal diseases is difficult using present methods. Traditional approaches for predicting when disease activity will occur have proved inadequate in some cases. New diagnostic tests and updated methods of traditional tests will eventually allow clinicians to improve their skills in determining prognosis; however, most of these tests are not yet proved or economically feasible. At present, if a patient is currently healthy and has no past history of attachment loss, their prognosis is favorable. The probability of periodontal breakdown occurring in these patients before the next regularly scheduled maintenance visit is slim. A history of attachment loss is the best predictor of future loss, but determining when more loss will occur is problematic. Clinical signs of inflammation, especially bleeding on probing and the presence of suppuration, also appear to predict breakdown, but to a lesser degree than previous attachment loss. It appears that the future holds much promise for improving our ability to make accurate prognoses, especially in cases of aggressive periodontal problems, but until these advances are well tested, traditional methods continue to be the standard.

Humans↗
PubMed1992

Radiographic evaluation of adult patients with blunt renal trauma.

Recent reports in the literature suggest that radiographic evaluation of the normotensive blunt trauma patient with microscopic hematuria is no longer necessary. Several facilities, however, including ours, continue to perform excretory urography (IVP) routinely in this setting. To evaluate further whether this practice is indicated, we retrospectively reviewed the records of 317 adults who presented to our facility between May 1986 and December 1989 after blunt trauma with resultant microscopic hematuria but no shock. All patients were radiographically assessed with an IVP. Of the 317 studies 29 (9%) had an abnormal result, including 28 with renal contusion and 1 with a nonfunctioning kidney (in which case further evaluation revealed a congenitally absent kidney). No significant urological injury was identified. Thus, no injury would have been missed if a policy of observation had been followed in these patients. Our data support other reports in the literature that radiographic staging is not necessary in the adult blunt trauma patient with microscopic hematuria but no shock.

Adult↗
PubMed1992

Angiographic embolization of renal stab wounds.

Nonoperative management of renal stab wounds following complete radiographic assessment has become an accepted if not preferred therapeutic option. Selected injuries, however, including renal artery branch injuries, often require surgical intervention and result in partial or total nephrectomy. We report our experience with 16 renal branch arterial injuries secondary to street stabbing during the last 10 years that were managed with angiography and embolization techniques. Angiography with embolization was the initial treatment in 11 patients, while 5 had undergone emergency surgical intervention initially because of hemodynamic instability. Subsequently, gross hematuria recurred in the latter 5 patients and they were managed angiographically. Overall, 14 of 16 patients had prompt hemostasis documented either on the post-embolization angiogram or by clinical assessment. In 2 patients bleeding was increased but partial nephrectomy ultimately was required. Complications included nontarget embolization in 2 patients: 1 subsequently had hypertension and 1 had no untoward effect as a result of this complication. We conclude that angiography with transcatheter embolization techniques provides a safe and effective means of managing renal artery branch injuries secondary to stab wounds.

Adolescent↗
PubMed1992

The competitive ability and fitness components of the Methoprene-tolerant (Met) Drosophila mutant resistant to juvenile hormone analog insecticides.

The Methoprene-tolerant (Met) mutation of Drosophila melanogaster results in a high (100-fold) level of resistance to the insecticide methoprene, a chemical analog of juvenile hormone. Pest species that are under control with methoprene may therefore have the potential to evolve resistance via a mutation homologous to Met. To evaluate the potential of such mutants to persist in wild populations, we must understand the fitness of flies carrying Met. In the absence of methoprene, Met flies were outcompeted by a wild-type strain both in a multigeneration population cage and in single-generation competition experiments. To determine which fitness component(s) is responsible for the competitive disadvantage, the survival, time of development, and fecundity of flies homozygous for each of five Met alleles were compared with wild type. Small but significant differences were found between the pooled Met alleles and wild type for pupal development time, pupal mortality, and early adult fecundity. These differences result in a large competitive disadvantage. Although Met flies were found to have reduced fitness by these measures, the phenotype is not as severe as might be expected from a knowledge of the disruption of juvenile hormone regulation seen in Met flies. It is concluded that (1) although Met flies have a large advantage under methoprene selection, they will quickly become outcompeted upon relaxation of methoprene usage, (2) even a seemingly severe disruption of juvenile hormone regulation has no drastic effect on the vital functions of the insect and (3) small differences in fitness components can translate into a large competitive disadvantage.

Alleles↗
PubMed1992

Pancreaticojejunostomy for chronic pancreatitis.

The treatment of chronic pancreatitis commonly yields disappointing results. Patients with chronic pancreatitis and a dilated pancreatic duct can be treated by longitudinal pancreaticojejunostomy. In order to evaluate the procedure, 20 patients undergoing pancreaticojejunostomy were followed for a median time of more than 5 years. Their clinical characteristics and outcomes have been compared with a group of 43 patients with chronic pancreatitis and small pancreatic ducts. There were no differences between the two groups in the major epidemiological parameters, except that calcification in the gland was more frequently noted in those with large ducts. The operation of longitudinal pancreaticojejunostomy could be accomplished with an acceptable morbidity. There was one death in the postoperative period. Seventy-six per cent of patients were found to have benefited clinically at five years, compared with 48% of those with small duct disease. This difference was statistically significant. Patients who benefited were defined by four factors; they were carrying out their usual occupation at the time of surgery, they were not narcotic dependent at the time of surgery, they had a pancreatic duct width greater than 7 mm and, they had totally abstained from alcohol from before the operation to the time of follow-up. Longitudinal pancreaticojejunostomy probably remains the best surgical treatment for suitable patients with chronic pancreatitis. The operation should only be performed when the pancreatic duct is greater than 7 mm in width. In such patients the operation produces considerable improvement of pain with minimal metabolic disturbance.

Adolescent↗
PubMed1992

Guided tissue regeneration around dental implants in immediate and recent extraction sites: initial observations.

Guided tissue regeneration, the principle of using membranes to exclude epithelial tissue during wound healing, thus enhancing periodontal regeneration, is an exciting addition to the implant armamentarium. However, additional clinical review of the results, advantages, and disadvantages of guided tissue regeneration is necessary before the procedure can be recommended for routine use. To this end, the author reports three representative cases in which membranes were used to encourage healing and discusses the results and problems.

Adult↗
PubMed1991

Primary adenocarcinoma of bladder.

Between April 1983 and December 1987, we have treated and followed 16 patients at the University of Southern California for adenocarcinoma of the bladder. In 10 patients, the cancer originated from a nonurachal source; all underwent radical cystectomy, bilateral pelvic lymph node dissection, and urinary diversion. The other 6 patients had an apparent urachal origin of their cancer. Half of these patients were treated with radical cystectomy and urinary diversion and half were treated initially with segmental cystectomy. Presenting characteristics (age, sex ratio, and symptoms) were similar for both groups. Three-year adjusted acturial tumor-free survival rates for the two groups were 48 percent and 31 percent, respectively. We advocate an aggressive approach of radical cystectomy, bilateral pelvic lymph node dissection, and urinary diversion for all invasive adenocarcinoma of the bladder, regardless of location.

Actuarial Analysis↗