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Biomedical subjects

W L Williams

Publications and source records attributed to W L Williams.

At least 37 records · Page 2Linked to original sources
PubMed1996

Usefulness of intracoronary stenting in acute myocardial infarction.

Data on the feasibility, safety, and clinical outcome of intracoronary stenting in acute myocardial infarction (AMI) are limited. This study examined the immediate angiographic results and the early and late outcomes in 32 patients who had stenting during AMI. Coronary angiograms recorded at the time of stenting were reviewed with quantitative measurements obtained on the "target" coronary lesion before and after stenting. Immediate angiographic success was achieved in 30 patients (94%). The minimal luminal diameter increased from 0.36 +/- 0.37 to 2.58 +/- 0.41 mm (p<0.0001). Two patients died in the hospital. Of the remainder, none had reinfarction or required bypass surgery, whereas 2 required repeat coronary angioplasty for recurrent ischemia. Although thrombus at the infarct-related coronary lesion was initially detected in 41% of the patients, its presence was not associated with adverse procedural outcome. Only 1 patient had persistent thrombus after stenting, which resolved with intracoronary urokinase. At a mean follow-up of 6.1 +/- 4.1 months, there was 1 additional cardiac death, and no patient had AMI or required repeat coronary angioplasty or bypass; among the 29 survivors, 86% were free of angina. Thus, intracoronary stenting of the infarct-related artery in the setting of AMI is associated with excellent immediate angiographic success and a favorable clinical outcome, and remains an option even in the presence of thrombus.

Adult↗
PubMed1996

Textural parameters based on the Spatial Gray Level Dependence Method applied to melanocytic nevi.

The purpose of this study is to evaluate the Spatial Gray Level Dependence Method (SGLDM) of texture analysis with respect to its ability to discriminate between melanocytic nevi and normal skin. Thirteen textural features based on the SGLDM were evaluated with respect to their relative sensitivities to both texture and tone. Ten features were found to be more sensitive to texture than tone and were selected for further study. Twenty-four digitized images of benign melanocytic nevi were obtained from six volunteers. Ten textural features were analyzed for each nevus and for surrounding sections of normal skin. Of these 10 features, 8 features can distinguish between textural properties of melanocytic nevi and surrounding skin.

Humans↗
PubMed1996

Survey of physicians' attitudes relative to the field of surgical oncology.

BACKGROUND: Surgical oncology as a distinct field of expertise is fairly young. The current study was designed to gain a better understanding of the attitude of practicing physicians toward the field of surgical oncology. METHODS: Three hundred twenty-seven physicians in the San Gabriel Valley (a suburban area adjacent to Los Angeles) responded to an anonymous survey of opinions regarding surgical oncology. Responses were placed into a computerized database. RESULTS: Of those responding, 179 were primary care physicians, 52 were general surgeons, 78 were gynecologists, and 18 were medical oncologists. Overall, 89% of physicians were familiar with the field of surgical oncology, but only 47% had ever heard of The Society of Surgical Oncology (SSO). Ninety-four percent of the respondents felt that a surgical oncologist should care for patients with complex cancer, and 63% of respondents felt that surgical oncologists should care only for patients with complex cancer. Familiarity with the field of surgical oncology and with the SSO correlated with the percentage of the physicians practice that was cancer related. Only 22% of physicians felt that the field of surgical oncology is redundant to the general surgical specialties. CONCLUSIONS: Results of the survey indicate that there is considerable recognition of the unique expertise of the surgical oncologist by the medical community. Unfortunately, many physicians are not familiar with the SSO. Educating physicians in the community about the SSO may help to further expand the role of the surgical oncologist in the care of the patient with cancer, standardize the expectations of the skills and training of a surgical oncologist, and set a benchmark for the surgical subspecialty.

Attitude of Health Personnel↗
PubMed1996

Cancer of the male breast: a review.

A review of 20 cases of male breast cancer in 17 patients from 1959 to 1990 was performed. The median age at presentation was 53.3 years (range: 29 to 79). At the time of diagnosis, 30% (6) patients were stage I, 65% (13) stage II, and 5% (1) stage IV. Surgery was the initial form of therapy in all cases either as a radical mastectomy, modified radical mastectomy, or total mastectomy. The median disease-free survival was 4.8 years with a 5-year disease-free survival of 41%, and with a 5-year overall survival of 47%. Seven patients are alive with no evidence of disease, two are alive with disease, five have died of disease, and two died of other causes. Estrogen receptor (ER) and progesterone receptor (PR) assays were performed on the tumors of 10 patients, with 80% being ER positive and 70% PR positive. The median disease-free survival for ER positive patients was 6 months with a 5-year disease-free survival of 12.5%. The overall median survival for this group was 2.9 years with an overall 5-year survival of 25%. In this review there was a high percentage of patients who were ER positive. The positive receptor status had value in predicting decreased survival.

Adult↗
PubMed1994

Colon cancer in blacks: age-related presentation and survival within a similar socioeconomic group.

Young blacks with colon cancer continue to have a poor survival rate for reasons that remain undetermined. Medical records of blacks with colon cancer diagnosed at an inner-city hospital during a 10-year period were reviewed. The cohort consisted of 118 indigent, nonmigratory patients grouped by age. Group 1 consisted of 11 patients under age 50, and group 2 consisted of 107 patients age 50 and over. Admission symptoms were significantly different between groups. Patients in group 1 presented with abdominal pain more often than patients in group 2, and none of the patients in group 1 had anemia or obstruction, which comprised 14% and 11%, respectively, of the presenting symptoms in group 2 patients. Overall, survival difference was significant; the survival rate was 22.8 months for group 1 and 64.2 months for group 2 (P < .02). There was no difference in stage at presentation to account for the decreased survival in group 1. It is possible that the overwhelming majority (45%) of patients in group 1 with abdominal pain actually had more virulent disease, which accounts for the short survival. These individuals must be targeted for more aggressive patient education, surveillance, early detection and treatment, and follow-up.

Adult↗
PubMed1992

The effects of cyclic imides on lipoprotein receptor binding and degradation of rat and human cells and effects on regulatory enzymes of lipid metabolism.

A series of cyclic imides, which possess a bulkier N-ring structure than phthalimide and saccharin, were shown to suppress LDL receptor binding, internalization and degradation of isolated rat hepatocytes, foam cells, human fibroblasts and mouse macrophages. The HDL receptor binding and internalization was accelerated in hepatocytes but not in other tissue types. In general, the HDL receptor activity and degradation was reduced by the cyclic imides. The in vivo studies with selected cyclic imides supported this finding in that 125I-LDL was not cleared from serum as rapidly as the control after 14 days of treatment, whereas 125I-HDL was cleared more rapidly by treated rats. The tissue uptake of 125I-LDL amd 125I-HDL was generally reduced in the treated rat tissues after 14 days dosing. These agents did not suppress HMG-CoA reductase activity in any of the tissue cell lines. A correlation existed between lower LDL receptor activity and stimulated HMG-CoA reductase activity in cells. The cyclic imides suppressed the activities of acyl-CoA cholesterol-acyltransferase, sn-glycerol-3-phosphate acyl transferase, and heparin-induced tissue lipoprotein lipase. Neutral cholesterol ester hydrolase activity and protein synthesis were markedly stimulated by the cyclic imides in the aorta foam cells, but not the other cell types.

Animals↗
PubMed1991

Mesenteric vein thrombosis associated with a familial deficiency of free protein S.

Signs and symptoms of an acute intra-abdominal emergency developed in a 26-year-old man; this emergency prompted surgical exploration. It was discovered that he had a devitalized small bowel as a result of mesenteric vein thrombosis. An extensive evaluation for hypercoagulable states disclosed that he had a normal total protein S concentration, but by assay and on crossed immunoelectrophoresis studies, he had a decreased concentration of free protein S. A family study demonstrated protein S deficiency in his father and in a sister. On a subsequent determination, the propositus had a decreased concentration of total protein S. This case illustrates the association of protein S deficiency with mesenteric thrombosis and serves to caution that a single determination of total protein S is not an adequate evaluation when the index of suspicion for a hypercoagulable state is high.

Adult↗
PubMed1991

L-alpha-phosphatidylcholine-induced stimulation of PGI2 production in canine gallbladders following hypovolemic shock and Escherichia coli sepsis.

In vitro production of PGI2 in canine gallbladders subjected to hypovolemic shock and Escherichia coli sepsis was studied to determine whether a precursor above arachidonic acid in the cyclooxyenase cascade might be operative in the production of prostacyclin, which, in turn, may play a role in the pathogenesis of acute acalculous cholecystitis (AC). L-alpha-phosphatidylcholine (LaP), an arachidonic acid precursor, was used as the test agent. LaP did not stimulate PGI2 production from either gallbladder surface in the hypovelimic animals or the mucosa of the septic shock group. However, it did stimulate PGI2 production from the SS serosa compared with controls, 1375 +/- 432 versus 633 +/- 198 pg/cm2/min (P less than .05). In conclusion, lack of stimulation of PGI2 in the hypovolemic model suggests that PGI2 does not play a role in AC. Alternatively, it may play a role in preventing this disease process in septic shock. This study demonstrates the use of precursors of arachidonic acid and the cyclooxygenase pathway as active participants in the production of PGI2, although it is unclear whether the prostacyclin produced helps prevent AC in septic shock.

Acute Disease↗
PubMed1991

Importance of timing of treadmill predictors for risk stratification after myocardial infarction: a five year follow-up study.

The prognostic value of information derived from clinical characteristics and exercise treadmill tests performed before discharge and repeated at three months was evaluated in 205 consecutive patients followed for five years. Recurrent myocardial infarction, unstable angina and mortality were tabulated. Survival was analyzed by the Kaplan-Meier life-table method and the Cox regression model. The major difference between the predischarge and three month intervals was the failure of exercise-induced ST depression to predict mortality from the predischarge test. However, it was predictive of mortality at three months when 76% survived five years with a positive ischemic response compared to 94% with a negative response (P less than 0.0005). In contrast, resting ST depression of at least 1 mm was associated with a very poor five year survival rate of 58.3% and 50% when assessed at both predischarge and three months (P less than 0.0005 and P less than 0.004, respectively). Selected univariately at the predischarge interval, the following characteristics were ranked in descending order of predictive power for five year mortality by discriminant analysis: history of previous infarction; exercise capacity; and ST depression on resting ECG greater than 1 mm. At three months, the same characteristics were selected. However, recurrent infarction and unstable angina were not predictable at either interval by any clinical or treadmill variable. Characteristics tending to reflect poor exercise capacity are stronger predictors of five year outcome than exercise-induced ischemia. While predischarge exercise testing for ST segment response failed to predict survival, this variable showed improved predictive power with repeat testing at three months.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1989

Intravenous dipyridamole-induced myocardial ischemia during percutaneous transluminal coronary angioplasty in humans.

Percutaneous transluminal coronary angioplasty was used as a model of controlled myocardial ischemia to study the effect of intravenous dipyridamole on myocardial ischemia and coronary hemodynamics in 10 patients. All patients had 1-vessel coronary artery disease with visualized collaterals. Intravenous dipyridamole increased myocardial ischemia during inflations. ST elevation, as measured by intracoronary electrogram, increased significantly from the control inflation to the second inflation after dipyridamole injection (0.05 +/- 0.23 vs 0.44 +/- 0.43 mV, p less than 0.03). Of the 10 patients, 8 developed new or more severe angina with subsequent inflations after dipyridamole. The pulmonary artery wedge pressure increased significantly from the control inflation to the fourth inflation (15 +/- 8 vs 20 +/- 9 mm Hg, p less than 0.05). The coronary wedge pressure showed a decreasing trend with subsequent inflations after dipyridamole but did not reach statistical significance. The double product (heart rate X blood pressure) was not significantly altered by dipyridamole. The findings indicate that intravenous dipyridamole increases myocardial ischemia during balloon occlusion. The constancy of the double product and the trend toward a decrease in coronary wedge pressure suggest that dipyridamole may induce ischemia by reducing the amount of collateral flow through a coronary steal phenomenon.

Adult↗
PubMed1989

Fatal angioedema associated with enalapril.

A 65-year-old male with a long history of congestive heart failure presented to the emergency room with facial swelling 7 h after the first dose of enalapril. He was treated with diphenhydramine and hydrocortisone which improved his angioedema. However, there was a profound relapse of the angioedema followed by respiratory arrest. He suffered severe anoxic brain damage and died five days later. It is likely that the long half-life of enalapril lead to this rebound phenomenon. Enalapril induced angioedema is reviewed with suggestions for management.

Aged↗
PubMed1988

Effects of palindromes on in vivo DNA replication and mutagenesis in bacteriophage phi X174 RF DNA.

Bacteriophage phi X174 mutants with insertions of palindromic DNA sequences are rapidly outgrown by competing wild-type phage (Müller & Turnage, J. Mol. Biol. 189: 285). The basis for this defect was investigated and found to be due to an exclusion event early in the infectious cycle, in which phage genomes with palindromic inserts were preferentially excluded by wt phage. In addition, we have obtained further evidence for a palindrome induced genetic instability. Both defects are dependent on palindrome size and sequence, consistent with a model which involves formation of cruciforms, or cruciform-like structures. We propose that formation of unusual DNA secondary structures reduces the effectiveness of replicative form (RF) DNA to interact with limiting replication factors or membrane binding sites, possibly because of interaction with the host recombination system.

Bacteriophage phi X 174↗
PubMed1988

Inhibition of nucleic acid synthesis in P-388 lymphocytic leukemia tumor cells by helenalin and bis(helenalinyl)malonate in vivo.

Although the parent sesquiterpene lactone, helenalin, and its derivative, bis(helenalinyl)malonate, are structurally related chemically, they demonstrate differences in their antineoplastic activity, with bis(helenalinyl)malonate being much more active against P-388 lymphocytic leukemia cell growth (T/C% = 261) compared with helenalin (T/C% = 162). Previous studies have shown that both agents strongly inhibit protein synthesis in vivo by greater than 70% after 3 d of administration and in vitro by 50% at a 100 microM concentration of drug. This inhibition of protein synthesis of P-388 cells may be partially responsible for the cytotoxicity of the drug. These agents also inhibit nucleic acid synthesis in vivo, with DNA synthesis being suppressed by greater than 90% after 2 d of administration of drugs at the therapeutic dose. Of the sulfhydryl-bearing enzymes involved in nucleic acid synthesis that were assayed, only the activities of inosine-5'-monophosphate (IMP) dehydrogenase and the ribonucleotide reductase complex were inhibited by greater than 50% by these sulfhydryl-reactive drugs, which would account for the observed inhibition of nucleic acid synthesis in the P-388 cells. The inhibition of the activities of these enzymes lowered the deoxyribonucleotide levels in P-388 cells, which would explain the overall suppression of DNA synthesis by the sesquiterpene lactones.

Animals↗
PubMed1988

Effect of low-dose irradiation upon T cell subsets involved in the response of primed A/J mice to SaI cells.

A/Jax (A/J) mice primed to Sarcoma I (SaI) exhibit an augmented response in association with low-dose (0.15 Gy) irradiation. This phenomenon is best demonstrated in tumour neutralization (Winn assay) or cell transfer experiments utilizing mice depleted of thymus-derived (T) cells. It is particularly dependent upon the duration of priming and the growth characteristics of the tumour in the primary host. The importance of these two variables appears to relate to their influence upon the cell types responsible for the host response, and includes both an effector and a suppressor component. Radiation-induced inhibition of the suppressor component appears responsible for low-dose augmentation and results in injury to a T cell of the Lyt-1-2+ phenotype. In Winn assays employing equal numbers of immune spleen cells and SaI cells, the smallest tumours are associated with Lyt-1-positive (Lyt-1+2- and Lyt-1+2+) cells and exposure to 0.15 Gy markedly inhibits their anti-SaI activity. Thus, even though the effect is in the opposite direction, both the effector and suppressor components of the anti-SaI response in A/J mice are exceedingly radiosensitive.

Animals↗