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T M Maxwell

Publications and source records attributed to T M Maxwell.

At least 19 recordsLinked to original sources
PubMed2001

A common deletion at chromosomal region 17q21 in sporadic prostate tumors distal to BRCA1.

Prostate cancer is the most common cancer in males in the United States, yet the etiology of this disease is still poorly understood. In previous work from our laboratory, one or more deleted regions were found in prostate tumors distal to the breast and ovarian cancer susceptibility gene (BRCA1) on chromosome 17. This suggested that genes at 17q21 may play a pivotal role in prostate cancer progression, and there may be new tumor suppressor genes at this locus. We now present a physical map built with P1, P1 artificial chromosome, and bacterial artificial chromosome clones encompassing a DNA sequence anchored by multiple STS markers. The analysis of prostate tumors indicated an 85-kb novel commonly deleted interval flanked by D17S1184-D17S183-D17S1203-D17S1860, which is at least 470 kb distal to the BRCA1 gene. Fifty-four of 126 prostrate cancer cases (43%) showed a deletion by a direct FISH technique using P1 probes in this region. Searching with clone end sequences in the sequence database BLAST, the deleted clone covered genomic DNA sequence that contained upstream binding factor (UBF), EPB3 genes, SHCL1, ASB-4-like sequence, and acidic protein-like sequence. PCR for the ESTs confirmed that these genes or ESTs are within the deletion region. Our results will be helpful for finding candidate tumor suppressor genes in prostate cancer.

Chromosome Deletion↗
PubMed1999

Chromosomal clues to the development of prostate tumors.

BACKGROUND: Cytogenetic, molecular cytogenetic, and molecular studies of prostate cancer have revealed an enormous amount of data regarding chromosomal loci that are aberrant in prostate tumors. METHODS: These data have been compared and condensed in this review to determine which chromosomes and chromosome sites have been most frequently reported. RESULTS: Loss of the Y chromosome, gain of 7, 8, and X, and interstitial deletions on 6q, 7q, 8p, 10q, 13q, 16q, 17q, and 18q are the most prevalent. CONCLUSIONS: A potential model for genetic control of tumor progression is presented, as are data regarding the evaluation of a new series of tumors.

Chromosome Aberrations↗
PubMed1998

Chromosome 7 abnormalities in prostate cancer detected by dual-color fluorescence in situ hybridization.

Aneusomy of chromosome 7 and loss at 7q (especially 7q31.1) have been reported in prostate cancer. To further investigate abnormalities of 7q and the relationship with whole chromosome 7 changes, we have conducted a dual-color fluorescence in situ hybridization (FISH) analysis on isolated nuclei from 28 primary prostate cancers. A pericentromeric probe for chromosome 7, five newly isolated sequence-specific bacterial artificial chromosome (BAC) probes from 7q31.1, and one BAC for the epidermal growth factor receptor (EGFR) gene at 7p12 were used in dual color hybridizations. Pericentromeric probes for chromosomes X and 4 were also used as controls. Sixteen (57.1%) of the 28 tumors showed clonal aberrations. Nine of them were trisomy 7 and four were hypertetrasomy for chromosome 7. Deletions at 7q31.1 were found in two of the high grade tumors. With the exception of these two cases, all other cases showed concordant results using all probes. These findings confirm previous studies that aneusomy of 7 is associated with prostate cancer progression, and there may be a tumor suppressor gene (TSG) at 7q31.1 which is associated with tumor progression. In addition, our study indicates: (1) the deletion pattern of individual nuclei infers that deletions at 7q31.1 precede reduplications of chromosome 7; and (2) the amplification of EGFR was not detected at the DNA level, suggesting that activation of this oncogene may play a minor role in prostate cancer.

Aneuploidy↗
PubMed1994

Superficial femoral vein: a useful autogenous harvest site.

PURPOSE: The purpose of this study was to present the use of superficial femoral vein (SFV) as an arterial bypass graft when ipsilateral saphenous vein is inadequate. METHODS: Data collected prospectively were reviewed on 24 patients (25 limbs) who had an arterial bypass with SFV performed by the authors between January 1, 1988, and December 31, 1991. Many anatomic sites are represented. The indication for operation was gangrene in six patients, severe rest pain or ulceration in 11, mild to moderate rest pain in six, and graft infection in two. There had been 42 previous reconstructions in these 25 limbs. RESULTS: There has been surprisingly little long-term disability from removal of the SFV. Immediately after surgery four limbs developed acute venous congestion that resolved quickly. Twenty percent of the patients with patent grafts have continued to wear a pressure gradient stocking for swelling 1 year after surgery, one patient requires additional pressure to control induration. All grafts were patent at 30 days. During a mean follow-up of 2 years, three grafts have required revision, and three have occluded. Stenosis did not develop at valve sites or in the body of the SFV portion of any of these grafts. There were two deaths from heart-related causes in the first 30 days after operation. Life-table analysis for the whole group shows a primary patency rate of 66% (SE 10.3%) and an assisted patency rate of 80% (SE 8.7%) at 2 years. CONCLUSIONS: SFV harvest is well tolerated, even in the absence of ipsilateral saphenous vein. The magnitude of the operation is greater than saphenous vein harvest but yields a thick-walled vein of excellent diameter with many applications as an autogenous conduit, particularly where a large-diameter graft is indicated.

Aged↗
PubMed1992

Dyslipidemias among normoglycemic members of familial NIDDM pedigrees.

OBJECTIVE: To examine the hypothesis that hyperinsulinemia among relatives of NIDDM probands will increase the prevalence of DLPs, we measured insulin levels and examined the frequency of DLPs among NIDDM pedigree members. RESEARCH DESIGN AND METHODS: We performed 2-h 75-g OGTTs and measured lipid and insulin levels of 287 family members and 86 spouses from 16 large Utah pedigrees ascertained for greater than or equal to 2 siblings with NIDDM. RESULTS: One-hour insulin levels were higher among 206 family members with NGT than among 65 NGT spouses (483.3 vs. 361.7 pM, P = 0.05). Among the NGT family members, 32% had cholesterol levels at or above the age- and sex-specific 90th percentile level defined by the LRC studies, 33% had HDL levels less than or equal to 10th percentile, and 20% had triglyceride levels greater than or equal to 90th percentile. DLP (any of the three abnormalities) was found among 58% of NGT family members, which was significantly higher than the expected 27% (P less than 0.00001) and the prevalence among spouses of 45% (P less than 0.05). By NCEP criteria for hyperlipidemia, 40% of family members met criteria for diet and/or pharmacological therapy. CONCLUSIONS: Normoglycemic members of NIDDM pedigrees have a high prevalence of DLPs, which approaches the prevalence in patients with NIDDM. Our data suggest that members of NIDDM pedigrees should be screened carefully for lipid abnormalities.

Adult↗
PubMed1991

Insulin and glucose levels and prevalence of glucose intolerance in pedigrees with multiple diabetic siblings.

Hyperinsulinemia may be an early inherited marker for a defect in insulin action that subsequently results in glucose intolerance and non-insulin-dependent diabetes mellitus (NIDDM). To examine the role of hyperinsulinemia in individuals at high genetic risk for NIDDM and determine the prevalence of impaired glucose tolerance (IGT) and newly diagnosed diabetes in members of NIDDM pedigrees, we studied 310 members of 16 pedigrees ascertained for greater than or equal to 2 NIDDM siblings. Nondiabetic members of all pedigrees were examined by 75-g oral glucose tolerance test with fasting and 1-h insulin levels. Participants had height and weight recorded. Spouses of pedigree members (n = 88) served as control subjects. The spouse control subjects were older and slightly more obese than the undiagnosed pedigree members. The prevalence of IGT was 14.8% in spouses and 7.7% in pedigree members, and NIDDM was present in 11.3% of spouses and 2.3% of previously undiagnosed pedigree members. However, neither spouses nor pedigree members differed significantly from published age-specific prevalence rates for IGT or newly diagnosed NIDDM. Insulin and glucose levels were examined in pedigree members with normal glucose tolerance (NGT). Fasting insulin levels were not significantly different between spouses and NGT pedigree members. However, after adjustment for age, weight (body mass index), and sex, NGT pedigree members had higher 1-h insulin levels and higher fasting and 1-h glucose levels than spouses. These differences were also evident when pedigree members with at least 1 affected (NIDDM or IGT) parent were compared with spouses with no family history of diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Color flow duplex screening of infrainguinal grafts combining low- and high-velocity criteria.

The aim of this prospective study was to evaluate the ability of duplex ultrasonography to identify infrainguinal grafts at high risk for failure. The criteria used identified low flow by low peak systolic velocity (less than 45 cm/s) and stenosis by high velocity (greater than 300 cm/s) or by velocity at the stenosis three times the velocity in the adjacent normal graft. A total of 114 patent grafts were scanned and compared with concurrent angiograms. Duplex scanning correctly identified 18 high-risk grafts by low-flow criteria and an additional 21 by stenosis criteria. There was one false-negative finding (sensitivity 98 percent). The velocity ratio of the stenosis to the adjacent graft was useful in estimating the degree of stenosis. Color flow duplex imaging reduced examination time through visual feedback by highlighting the graft and areas of high velocity. These results indicate that color flow duplex scanning, combining low- and high-peak systolic criteria, is a very sensitive screening test in the early detection of failing grafts.

Blood Vessel Prosthesis↗
PubMed1988

Reoperation within 2 years of aortofemoral bypass.

The authors analysed 267 consecutive primary aortofemoral grafts to identify the reasons for reoperation within the first 2 years postoperatively. Forty-one (8%) of the 521 limbs required a second operation. Precursors to reoperation were: occlusion of a superficial femoral artery (12%), gangrene (27%) and severe acute ischemia (35%). The rationale for reoperation was classified as technical 11, questionable selection (candidates for percutaneous transluminal angioplasty or inappropriate operation) 9, disease progress 11, residual symptoms 9, contralateral symptoms 1. The commonest technical problem was blind endarterectomy which preceded seven reoperations, five for thrombosis of the graft or a superficial femoral artery which was patent initially. Although 218 limbs had an occluded or severely stenosed superficial femoral artery, only 26 (12%) required reoperation within the first 2 years. The authors believe that the incidence of reoperation after aortofemoral bypass can be reduced by identifying the limbs at risk, by appropriate selection for percutaneous transluminal angioplasty, avoiding blind outflow endarterectomy and considering concomitant femoropopliteal bypass when gangrene is present.

Adult↗
PubMed1982

Intermittent claudication in an athlete--popliteal artery entrapment: a case report.

This case study reports a 26 year old female athlete who presented with a history of cramp-like right calf pain. She was limited to a walking distance of only three blocks. She had been referred to the Sports Medicine Clinic with a diagnosis of "shin splints". On examination of the pedal pulses it was found that the right posterior tibial pulse was absent. A diagnosis of popliteal artery entrapment was made which was confirmed by Doppler studies following treadmill walking and femoral arteriograms. Surgery was performed which included resection of the entrapped artery by the plantaris tendon and endarterectomy, plus patch graft angioplasty. The artery had been completely occluded. The patient resumed full activity pain free. This case report emphasizes that all leg pains in athletes are not variants of "shin splints". Popliteal artery entrapment is an uncommon condition that requires early detection. A detailed history and thorough examination of the peripheral pulses is essential to prevent long term sequelae of arterial deficiency.

Adult↗
PubMed1981

Experience with 130 polytetrafluoroethylene grafts.

One hundred thirty operations utilizing polytetrafluoroethylene (Gore-Tex) grafts were analyzed after follow-up of 1 to 3 years. The results of femoropopliteal below-knee and femorotibial grafts were disappointing. The polytetrafluoroethylene graft is versatile and allows crossing of the knee joint. It will maintain patency into a poor outflow tract and has a low complication rate. Thrombectomy can be accomplished easily and late. The main disadvantage appears to be neointimal hyperplasia, most obvious when the graft is inserted into small vessels. Sudden occlusion is not uncommon. The polytetrafluoroethylene graft is still a second choice to vein. Its use as a composite graft with vein to small vessels deserves further examination.

Adult↗
PubMed1980

Iliac-vena caval fistula: an uncommon acute traumatic arteriovenous fistula.

Acute traumatic arteriovenous fistulas in major abdominal vessels are relatively rare. They are often difficult to detect without arteriography in a patient with multiple injuries, without a nonexpanding hematoma. To the authors' knowledge this is the first report of an acute traumatic iliac-vena caval fistula. The value of arteriography in diagnosis and the need for early recognition and operation of these lesions are stressed. Definitive arterial and venous reconstruction should be performed whenever feasible.

Abdominal Injuries↗
PubMed1980

Symposium on trauma. 1. Resuscitation priorities and assessment of the patient with multiple injuries.

A system for the assessment of patients with multiple injuries is presented in which the torso is divided into three regions: (a) the great vessels, heart and esophagus, (b) the intrathoracic abdomen and (c) the pelvis and retroperitoneal space. The three areas of abdominal injury were subdivided into individual organs likely to be the site of serious injury. This system has been of great value in arousing suspicion of injury to specific organs that might otherwise have remained hidden.

Abdominal Injuries↗
PubMed1978

Rectal injuries.

Injuries to the rectum have always been associated with a high mortality. This was reduced when exteriorization was introduced, particularly when it was combined with prompt and effective resuscitative measures. Experience gained during the Vietnam war demonstrated the considerable benefit of washout of the distal rectal segment. The author describes the course of management he advises. After initial resuscitation, roentgenography of the pelvis and abdomen is necessary. Antibiotics should be administered preoperatively. Through a midline incision the rectal wounds are repaired and a proximal diverting colostomy is performed. The nonfunctioning bowel segment should then be thoroughly washed out. Careful search must be made for associated injuries that require attention.

Colostomy↗
PubMed1975

Noninvasive study of extremity perfusion by potassium 43 scanning.

In nine patients with lower extremity symptoms of arterial insufficiency, potassium chloride K 43 was injected intravenously during rest, reactive hyperemia, or exercise. Decreased radioactivity in muscle tissue was observed to correspond with symptoms, physical findings, Doppler ultrasound pressures, and angiographic findings in all six who had the procedure. Studies following surgical endarteractomies in two, a bypass procedure in one, and exploration without attempted reconstruction in one showed good correlation with postoperative symptoms, physical findings, and pressure measurements using Doppler ultrasound in three of four patients. The fourth patient showed no change on the postoperative study despite clinical imporvement. These findings suggest that intravenously administered radioactive potassium provides a noninvasive means for demonstrating the perfused muscle mass of the extremities with delieation of ischemic areas. The risk of arterial puncture is eliminated, and the ability to visualize perfusion patterns during exercise is unique to this method.

Adult↗