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Biomedical subjects

L Williams

Publications and source records attributed to L Williams.

At least 19 recordsLinked to original sources
PubMed1992

Synthesis and SAR of 6-substituted purine derivatives as novel selective positive inotropes.

A series of purine derivatives was prepared and examined for selective inotropic activity in vitro and in vivo. Thioether-linked derivatives were superior to their oxygen and nitrogen isosteres. Substitution of electron-withdrawing groups on the benzhydryl moiety of these agents increased potency. The best compound of the study, 17 (carsatrin), was examined further and demonstrated selective oral activity as a positive inotrope. These compounds are presumed to act by affecting the kinetics of the cardiac sodium channel by analogy to the prototypic agent DPI 201106 (1). Their high selectivity for increasing contractile force and dP/dt without affecting blood pressure or heart rate is consistent with this mechanism. Carsatrin (17) was selected as a potential development candidate.

Animals↗
PubMed1992

A truncated form of fibroblast growth factor receptor 1 inhibits signal transduction by multiple types of fibroblast growth factor receptor.

A truncated form of the type 1 fibroblast growth factor receptor (FGFR1) lacking most of its cytoplasmic domain was tested for its ability to inhibit signal transduction by each of three different wild-type FGFRs (FGFR1, 2, and 3). When the truncated FGFR1 was expressed in Xenopus oocytes in excess of each wild-type FGFR, mobilization of intracellular calcium mediated by the wild-type FGFRs was completely blocked. The truncated FGFR did not inhibit signal transduction by the co-expressed platelet-derived growth factor beta-receptor. A form of truncated FGFR1 which lacked the first immunoglobulin-like domain also inhibited signal transduction by wild-type FGFRs. Truncated FGFR formed complexes with wild-type FGFR in the presence of basic FGF in intact cells. These observations were consistent with the hypothesis that the truncated FGFR interacted with wild-type FGFRs to form nonfunctional heterodimers, thus eliminating the signaling by the wild-type FGFRs. The observation that signaling by multiple types of FGFR can be blocked by a single type of truncated FGFR suggests that the different types of FGFR can interact with each other in ligand-mediated complexes. These findings provide a molecular basis for inhibiting the actions of FGFs in vivo.

Animals↗
PubMed1992

Ovarian cancer screening. The search for cost-effective methods.

The search goes on for an effective screening test for ovarian cancer. This deadly disease has eluded attempts at early detection with the currently available methods. Dr Williams examines the research regarding various screening methods and suggests areas of promise for future study.

Abdomen↗
PubMed1992

Effects of dietary magnesium and nickel on growth and bone characteristics in rats.

We examined the interaction of dietary magnesium (Mg) and nickel (Ni) on growth and, in particular, the size, composition and mechanical properties of bones in weanling rats. Male rats were fed a diet with 0.3, 1.0 or 2.0 times the recommended concentration of Mg and adequate amounts of other nutrients. After a week, groups fed the low- and high-Mg diets were subdivided and fed the same concentration of Mg plus 0 or 500 mg Ni/kg diet (from Ni chloride) for the remaining 7 weeks. Rats fed low Mg with added Ni grew slowly and had smaller femurs and vertebrae that contained less ash and withstood less force before breaking or compression than did bones of rats fed the low-Mg diet without Ni. However, the breaking stress calculated for femurs from Mg-depleted, Ni-supplemented animals was increased. Ni did not produce these effects when added to a diet high in Mg. Compared with high dietary concentrations, the low-Mg intake had little effect unless Ni was added.

Animals↗
PubMed1992

Drug therapy in the elderly.

The segment of the population older than 65 accounts for about 25% of the total drug expenditures in developed countries. This figure is predicted to reach 40% by the year 2030. Drug therapy in the elderly can be complicated by many factors. The pharmacokinetic processes of absorption, distribution, metabolism, and elimination are altered by the physiologic changes of aging involving body composition and organ function. While the extent of drug absorption is not affected by age, few drugs have delayed rates of absorption after oral administration. Changes in body composition, protein binding, and blood flow do affect the concentrations of free unbound drug, the volume of distribution, and elimination half-life of a number of drugs. The primary goal of drug therapy in the elderly is to improve the quality of life. When medical therapy is required, the physician must be aware of the potential effect of age and disease on pharmacokinetics and pharmacodynamics and of the possible ramifications for adverse drug reactions or interactions. By increasing our knowledge of the action and effects of drugs in the elderly, and by enhancing communication and understanding between physician and patient, we can significantly improve the overall quality of care for the elderly patient.

Aged↗
PubMed1992

A target weight procedure for disordered water balance in long-term care facilities.

1. Water intoxication is a severe complication of disordered water balance. Hyponatremia precedes water intoxication and can be identified through abnormal diurnal weight variation. 2. The St. Louis Target Weight Procedure (STWP) is a nonintrusive method that includes a client's baseline weight, frequent weights throughout the day, a target weight of 5% above the baseline weight, and restricted fluids if the target weight is exceeded. 3. The STWP was positively related to an increase in urine concentration; thus it is successful in restoring normal fluid balance.

Adult↗
PubMed1992

The role of family factors, physical abuse, and sexual victimization experiences in high-risk youths' alcohol and other drug use and delinquency: a longitudinal model.

Our understanding of the adverse effects of early child physical and sexual abuse has developed to a point where there is need to elucidate the processes by which various developmental outcomes occur. Limited variability on key measures of family stress and in youths' drug use, other delinquent behavior and abuse histories in the general population has limited theory development. Using data from an ongoing, longitudinal study of juvenile detainees, we test a developmental damage model of the relationships among the youths' family background and problem factors, their sexual victimization and physical abuse experiences, and their substance use and delinquent behavior over time. The hypothesized model was supported by the data. Theoretical and policy implications of the results are drawn. In particular, early intervention with high-risk youths and their families is needed to address effectively their problems and troubled behavior before drug use and delinquent careers become firmly established.

Adolescent↗
PubMed1992

The role of secondary cytoreductive surgery in epithelial ovarian malignancies.

The benefit of aggressive primary cytoreductive surgery in the management of patients with advanced epithelial ovarian cancer has been confirmed. The value of secondary cytoreductive surgery, however, is less clear. This approach is being studied in four categories of patients: (1) those clinically free of disease after a planned regimen of first-line chemotherapy who are found to have macroscopic tumor at second-look laparotomy; (2) patients found to have bulky, unresectable tumor at initial surgery and who undergo interval cytoreduction as part of a planned chemosurgical treatment approach; (3) those with recurrent disease after a prolonged disease-free interval; and (4) patients who progress on first-line therapy. This article reviews the technical success rates, complications, and survival in patients undergoing these secondary cytoreductive procedures.

Combined Modality Therapy↗
PubMed1992

A structural model examining the relationship between physical child abuse, sexual victimization, and marijuana/hashish use in delinquent youth: a longitudinal study.

A structural model of the relationships among physical abuse and sexual victimization experiences, marijuana/hashish use (measured by self-report and urine test data) and self-reported delinquent behavior (theft crimes, index offenses, crimes against persons, drug sales and total delinquency) over time was tested in a longitudinal study of juvenile detainees. The hypothesized model was supported by the data. Theoretical, research and policy implications of the results are drawn.

Adolescent↗
PubMed1992

Black, middle-class women in San Antonio, Texas.

Fifty-six African-American women between the ages of 20 and 84 who had completed a minimum of 4 years of college and were employed in professional positions (eg, teacher, technician, lawyer, and physician) were identified in San Antonio, Texas. Specific information concerning marital status, income, home ownership, family of origin, presence of professional siblings, husbands' characteristics, medical and psychiatric health, and significant influences in their lives were obtained by a semistructured interview. This article summarizes the results of these interviews and presents the techniques used to identify this sample of African-American, middle-class women.

Adult↗
PubMed1992

Neuropsychiatric effects of drugs in the elderly.

Since the elderly consume large numbers of drugs, drug-induced disease must be high on the list as a suspected cause of changes in behavior. Neuropsychiatric side effects of drugs in the elderly are not rare events. While proceeding to investigate medical, neurological, and psychiatric causes of a change in the cognitive status or behavior in an elderly patient, it is important to consider a possible psychotoxic drug as an offender or co-offender. Failing to do so may lead to inappropriate testing and further unnecessary and possibly deleterious therapeutic measures. In the case of dementia, the worst treatment would be institutionalization before identifying a drug as the cause of the cognitive dysfunction.

Aged↗
PubMed1991

Quadruple immunosuppression in renal allografts--the Auckland experience.

Recipients of live related and first cadaveric renal allografts were retrospectively reviewed before and after institution of a standardized regimen incorporating greater immunosuppression, (by the addition of antilymphocyte preparations). The two review groups were comparable with 11 live related and 27 first cadaver grafts in each. Despite a small advantage in terms of graft survival and diminished rejection, this was at the expense of septic morbidity. The implications of this are discussed.

Antilymphocyte Serum↗
PubMed1991

Asynchronous development of the rat colon.

Mucosal ridge and fold formation, apoptosis and the occurrence of secondary lumina within the epithelium are morphological features associated with the development of the colon. These processes, however, do not occur synchronously in the various segments of the colon. In the caecum and ascending colon of the rat, fold formation, apoptosis and secondary lumina result in the development of villi by day 22 after conception, and by postnatal day 3 in the transverse colon. These villi persist in the rat colon until approximately postnatal day 10. The presence of colonic villi may be correlated with the increased food intake and fluid absorption during this early postnatal period. Villus formation does not take place in the developing descending colon.

Animals↗
PubMed1991

The use of a brief movement restriction procedure to eliminate severe inappropriate behavior.

The effect of a brief movement restriction (BMR) procedure on the maladaptive behavior of two severely mentally retarded persons was evaluated using a multiple baseline research design. Following a functional analysis of the maladaptive behaviors, baseline data were collected on the frequency of smearing in a six year old boy and the frequency of aggression-destruction and stereotypic behavior in a 24 year old man. Following the baseline period a treatment package that included reinforcement for alternative behavior and BMR were first introduced for feces smearing. After feces smearing had shown a reduction with the first client the treatment package was introduced for aggression and destruction with the second client. After aggression and destruction had been reduced, the treatment package was added for stereotypy. The treatment package completely eliminated each of the target behaviors and they remained absent during a long follow-up period.

Adult↗