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Biomedical subjects

S Levenson

Publications and source records attributed to S Levenson.

31 records · Page 2Linked to original sources
PubMed1984

Radiation survival properties of cultured vascular smooth muscle cells.

Vascular injury has been suggested as a possible mechanism for late radiation damage to various organs. However, little is known about the radiobiology of cells of the blood vessel wall. We have studied the radiation survival properties of exponentially growing cultures of vascular smooth muscle cells. Medical smooth muscle cells were obtained from the thoracic aortas of 3- to 4-month-old Sprague-Dawley rats and were propagated in cell culture using standard techniques. Cultures from different strains were irradiated using 137Cs gamma radiation after varying periods in culture. Clonogenic survival was measured via colony formation assays. The mean D0 for seven survival curves utilizing four different strains of cells was 147 +/- 22 rad (range 117-176) and the mean extrapolation number (corrected for colony multiplicity) was 3.7 +/- 2.7 (range 1.1-9.5). Split dose survival assays demonstrated repair of sublethal radiation damage within the first 4 hr with recovery factors approximately equal to the extrapolation number. We conclude that rat aortic medial smooth muscle cells show moderate radiosensitivity similar to that measured in vitro for a variety of mammalian cell lines and in vivo for epithelial tissues in rodents.

Animals↗
PubMed1979

Nonoliguric acute renal failure.

The course of nonoliguric acute renal failure (ARF) in 11 patients was analyzed. The possible etiology of the renal failure was multiple in all cases and did not differ from that seen in oliguric acute tubular necrosis (ATN). Other than the urine volume, which ranged from 510 to 2,325 ml/day, there was no major clinical or biochemical difference between these cases of nonliguric ARF and those described for oliguric ATN. Creatinine clearance, however, was higher than anticipated in oliguric ATN and ranged from 2.8 to 15.0 ml/min. There was a direct relationship between creatinine clearance and daily urine volume. The essential difference between oliguric and nonoliguric renal failure appears to be the lesser degree of renal damage in the nonoliguric form.

Acute Kidney Injury↗
PubMed1976

Antipyretic and antiviral action of vitamin A in Moloney sarcoma virus- and poxvirus-inoculated mice.

Six week-old male CBA/J mice fed a commercial powdered laboratory chow or the same chow supplemented with vitamin A palmitate (150,000 U/kg) were inoculated with either the Moloney strain of murine sarcoma virus (M-MuSV) or poxvirus. Central body temperature was measured daily. Both viruses elicited fevers, but the fevers were less pronounced and of shorter duration in the mice ingesting the vitamin A-supplemented diet. Palpable M-MuSV-induced tumors appeared later, were less frequent, grew more slowly, and were resorbed sooner in the mice fed the vitamin A supplement. Similarly, in these mice the appearance of pox lesions was delayed, their numbers reduced, and their disappearance hastened.

Analgesics↗
PubMedDate not supplied

Wound healing in partial-thickness burn wounds treated with collagenase ointment versus silver sulfadiazine cream.

During burn care the wounds must be repeatedly debrided of adherent and loose debris until the decision is made to surgically excise and graft the wound or to await epithelialization. Though native proteolytic enzymes in the skin or those produced by colonizing bacteria can speed eschar separation, the use of exogenous enzymes for wound debridement may accelerate wound cleaning and healing. Collagenase digests native and denatured collagen in necrotic tissue. This multicenter trial of 79 patients with partial-thickness wounds compared the efficacy of collagenase ointment applied with polymyxin B sulfate/bacitracin powder with the efficacy of standard topical antimicrobial therapy (control) in which silver sulfadiazine cream (1%) was used to debride paired burn sites. Patients selected for the study had two noncontiguous, partial-thickness, comparably sized, and anatomically similar burn wounds. Ages of patients ranged from 5 to 60 years (mean 33 years). The total body surface area burned ranged from 2% to 30% (mean 13.6%). Mean burn sizes used for study treatment were 366 cm2 (26 to 2310 cm2) for collagenase sites and 355 cm2 (26 to 2394 cm2) for control sites. Sites on each patient were randomly assigned to treatment with either collagenase or control. Endpoints were time to clean wound bed (absence of retained debris) and time to healing (complete epithelialization). The sites treated with collagenase cleaned in less time (mean 9.3 days) than the control sites (mean 11.6 days). Similarly the collagenase sites healed faster than the control sites (mean 19 vs 22.1 days).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMedDate not supplied

A pilot survey of aquatic activities and related consumption of alcohol, with implications for drowning.

The investigators considered the relationship between participation in aquatic activities and the consumption of alcohol, with their implications for the risk of drowning. In a telephone survey with random-digit dialing, interviewers asked Massachusetts residents ages 20 years and older how often they engaged in various aquatic activities, in what settings, and how often they drank alcohol in connection with participation in aquatic activities. Of 294 respondents, 79 percent of the men and 72 percent of the women reported participating in aquatic activities during August 1988, the month prior to the interview. Respondents were asked to identify their most recent aquatic activity. The mean number of days of participation in the month was 13. The most frequently reported aquatic activities were swimming (76 percent), followed by sunbathing (74 percent), power boating (25 percent), and fishing from shore (15 percent). Among those persons reporting participation in aquatic activities, 55 percent had been at the ocean on the most recent occasion, 26 percent at lakes or ponds, 17 percent at pools, and 2 percent at rivers. Among those persons reporting aquatic activities, 36 percent of the men and 11 percent of the women reported having drunk alcohol on the most recent occasion. Those who reported drinking in aquatic settings were more likely to report driving after drinking than those who did not drive. Implementation of new Federal regulations and State laws concerning drinking and boating should be accompanied by public education on the risks of drowning if aquatic activities and alcohol consumption are combined.

Adult↗
PubMedDate not supplied

Effects of legislative reform to reduce drunken driving and alcohol-related traffic fatalities.

From 1980 through 1985, considerable progress was made across the Nation in reducing drunken driving and fatal automobile crashes. More than 400 chapters of local citizen groups concerned with reducing drunken driving were formed. New media coverage, measured in number of stories, increased fiftyfold from 1980 to 1984. More than 500 legislative reforms were passed. All States now have adopted a legal drinking age of 21. Many also adopted criminal and administrative per se laws and instituted penalty increases for drunken driving. By 1985, the total number of fatal crashes declined to 39,168, a decrease of 6,116, or 16 percent, from the 1980 level of 45,284. Single-vehicle fatal crashes occurring at night, those most likely to involve alcohol, declined by 20 percent, with 3,674 fewer crashes in 1985 than in 1980. Among teenage drivers, declines in fatal crashes were steeper: Fatal crashes decreased 26 percent, and single-vehicle night fatal crashes were down 34 percent. After 1984, however, the number of new citizen groups established and the number of stories appearing in the media began to decline. In 1986, after decreasing for several years, the number of fatal crashes rose 5 percent, and single-vehicle night fatal crashes rose 7 percent, up 1,060 from 1985. Among teenage drivers, the increase in single-vehicle night fatal crashes was even higher, up 17 percent. In 1987, single-vehicle night fatal crashes declined slightly but still remained higher than in 1983, 1984, or 1985. Legal changes, while helpful in reducing drunken driving crashes, may not be sufficient to achieve optimal long-term declines.To sustain the progress of the early 1980s, we need to:* Refocus community and media attention on the drunken driving problem. * Increase police enforcement and public support for enforcement of laws against drunken driving.* Heighten educational and enforcement efforts that target risky traffic behaviors more common among drunken drivers-particularly speeding and failure to wear seatbelts.* Develop educational efforts aimed at all segments of the population to increase informal social pressure to discourage drunken driving and riding in vehicles with drivers who are drunk.Traffic accidents remain the leading cause of death among persons ages I to 34; 52 percent of the 46,050 traffic fatalities in 1986 involved ad river or pedestrian who had been drinking. Without renewed attention to the problems posed by drunken driving, we may be unable to sustain the dramatic progress of the early 1980s.

Accidents, Traffic↗