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Biomedical subjects

L Lott

Publications and source records attributed to L Lott.

17 recordsLinked to original sources
PubMed2001

The Smith-Kettlewell Institute (SKI) longitudinal study of vision function and its impact among the elderly: an overview.

We present an overview of a multifaceted longitudinal study of vision function and its interaction with daily activities, health, and well-being among 900 persons aged 58 to 102 years at the first visit. Standard vision measures as well as nonconventional tests designed to assess visual performance under the nonideal conditions encountered in everyday life were used. Here we summarize a few of the findings to date, with an emphasis on a direct comparison of declines in different aspects of vision function with age. The rates of declines with advancing age vary widely for the different vision functions. Also described is the reading performance of the sample and its association with some of the vision measures. Furthermore, we describe some of the associations between vision test scores and extensive longitudinal health and functioning data collected by the Buck Center for Research in Aging. Findings show that many older people with good acuity are effectively visually impaired in performing everyday tasks involving low and changing light levels, stereopsis, glare, and low contrast. We also found that vision under nonideal conditions cannot be predicted from standard acuity on an individual basis.

Activities of Daily Living↗
PubMed2000

Interaction between hepatitis B virus core protein and reverse transcriptase.

Previous mutagenesis studies with hepatitis B virus (HBV) suggest that continued interactions with core are required for several steps in genomic replication. To examine core-polymerase (Pol) interactions, insect cells were coinfected with baculovirus constructs that independently expressed core and Pol. The results demonstrated several features with implications that core plays an interactive role with HBV Pol: (i) core coprecipitated with constructs expressing full-length Pol as well as the terminal protein (TP), reverse transcriptase (RT) and RNase H domains of Pol, independently; (ii) coprecipitation of core was not dependent on the presence of an epsilon stem-loop sequence; and (iii) core-Pol complexes migrated as intact capsid particles, as detected by sucrose gradient analysis. To analyze the structural and sequence requirements of core in recognition of Pol, a series of core mutants with two- to four-amino-acid insertions or carboxy-terminal deletions were assessed for Pol interaction. The results indicated that capsid formation is required but not sufficient for interaction with Pol and that the TP and RT domains of Pol have different requirements for interaction with core. To map the core binding sites on Pol, a panel of amino- and carboxy-terminal deletion mutants of the TP and RT domains of Pol were analyzed for interaction with core. At least three separate core binding sites on Pol were detected. This analysis begins to define basic requirements for core-Pol interactions, but further study is necessary to delineate the effects of these interactions on encapsidation and genome replication.

Amino Acid Sequence↗
PubMed1998

Late vascular occlusion of central lines in pediatric malignancies.

OBJECTIVE: To determine whether thrombi or vascular occlusion represent a late complication persisting several years after removal of central venous lines (CVLs) in children and adolescents treated for childhood cancer. METHODS: Children whose treatment for malignancy included placement of a CVL that had been removed at least 2 months previously were studied during scheduled follow-up that included contrast-enhanced computed tomography. Spiral volume acquisition was used to obtain 3-mm images from the chest apices through the right hilum, and three-dimensional reconstruction of angiograms was performed. Thrombosis/occlusion was defined as narrowing, obstruction, or filling defect of the deep venous system, with or without the formation of collateral veins. Charts were reviewed to document patient characteristics, previous CVL complications, administration of hyperalimentation, use of urokinase, and family history of venous thrombosis. RESULTS: Twenty-three patients treated for solid tumors and 2 treated for B-cell acute lymphocytic leukemia or lymphoma were studied. Lines had been in place from 0.2 to 36 months (median, 7.4) and were removed at 2.3 to 121.8 months (median, 32.5) before study. Nine patients received hyperalimentation for periods ranging from 2 to 38 weeks (median, 12). Four patients had required urokinase instillations, and one developed superior vena cava syndrome; 4 had a CVL-related infection (two superficial and two Candida line infections). Occlusion was seen on computed tomography angiograms in 3 of the 25 patients (12%; 95% confidence interval: 4.5-31%). One of the patients with occlusion had superior vena cava syndrome; none had a family history of thrombosis, use of a double lumen CVL, or multiple instillations of urokinase. CONCLUSIONS: Persistent asymptomatic vascular occlusion does occur as a late complication of CVL placement for treatment of childhood malignancies, although the frequency appears low among patients treated primarily for solid tumors. Prospective studies of large numbers of patients with a broader spectrum of diagnoses are necessary to define the incidence of and risk factors for this complication and to assess the need for prevention with anticoagulation or other therapy. Pediatricians caring for patients with a history of cancer and CVLs should be aware that these patients may have persistent vascular occlusion that could predispose them to recurrent thrombosis or postphlebitic syndrome.

Adolescent↗
PubMed1994

Pseudomonas aeruginosa bacteremia in immunocompromised children: analysis of factors associated with a poor outcome.

We identified 98 children and adolescents with cancer who were treated for Pseudomonas aeruginosa bacteremia over a 27-year period. The most common underlying disease was leukemia (lymphoblastic in 63 cases and myeloblastic in 17); in addition, 12 episodes were associated with solid tumors and 6 with other diagnoses. There were 29.5 episodes of P. aeruginosa bacteremia/1,000 cases of acute lymphoblastic leukemia, with a mortality of 27%, and 29.8 episodes/1,000 cases of acute myeloblastic leukemia, with a mortality of 24%; patients with solid tumors had an incidence of 5.0/1,000 cases and a mortality of 58% (P = .01 for mortality in leukemia vs. mortality in solid tumors, logistic regression analysis). Mortality was lower among children who developed bacteremia during remission therapy or induction therapy than among children who were being treated for relapse (P = .001). The majority (78%) of the 76 evaluated cases developed during periods when the absolute neutrophil count (ANC) was < 0.1 x 10(9)/L; mortality was higher among patients with such counts than among those with higher ANCs (36% vs. 14%, P = .04). Logistic regression analysis showed that perineal skin lesions were associated with higher mortality than were lesions at other sites of skin involvement (54% vs. 23%, P = .04).

Adolescent↗
PubMed1991

Pseudomonas aeruginosa cellulitis and ecthyma gangrenosum in immunocompromised children.

Pseudomonas aeruginosa skin infections are generally considered to be secondary manifestations of disseminated disease. A retrospective analysis of all cases of P. aeruginosa skin infections seen at St. Jude Children's Research Hospital since 1962 revealed 16 episodes of the infection (ecthyma gangrenosum, 8 episodes, 7 patients; cellulitis, 8 episodes, 7 patients) in which blood cultures were uniformly negative for P. aeruginosa. All cases were identified while the patients were receiving ambulatory care. Five episodes developed while the patients' neutrophil counts were greater than 1 x 10(9) cells/liter. Eight patients had acute lymphoblastic leukemia, 2 had acute myeloid leukemia, 2 had aplastic anemia, 1 had transient agranulocytosis and 1 had cyclic neutropenia. There were no solid tumor patients. Although patients received different antibiotic combinations, all had resolutions of their lesions without fatal complications. Patients diagnosed as having cellulitis required a mean of 9.2 days of treatment with intravenous antibiotics, as compared with 17.8 days for those with ecthyma gangrenosum (P less than 0.05 by the Wilcoxon test). These observations show that P. aeruginosa skin infections can develop in the absence of bacteremia in immunocompromised children.

Adolescent↗
PubMed1990

Risk of Haemophilus influenzae type b disease in children with cancer and response of immunocompromised leukemic children to a conjugate vaccine.

From 1969 to 1988, 8 cases of systemic Haemophilus influenzae type b (Hib) disease occurred among 5288 patients with cancer. For the first 4 years of life, systemic Hib disease was significantly greater in leukemic children than in the general population (606/100,000 vs. 90/100,000, respectively). Fifty children aged 2-6 years with acute leukemia were vaccinated with a Hib conjugate vaccine, ProHibit. The overall response rate was 50%; however, 75% of children receiving leukemic therapy for less than 12 months responded versus 18% of those treated longer. After vaccination, the geometric mean antibody concentration was 7.2 micrograms/ml, appreciably lower than for normal children of similar ages. After 12 months, the geometric mean antibody concentration had declined to 0.35 micrograms/ml, and 75% of subjects had antibody levels greater than or equal to 0.15 micrograms/ml. A booster dose for unsuccessfully vaccinated subjects was of minimal benefit. Children with acute leukemia in remission who were treated according to the leukemia therapy protocol of St. Jude Children's Research Hospital had a good likelihood of responding to the conjugate Hib vaccine if administered within a year of initiation of chemotherapy.

Adolescent↗
PubMed1990

The impact of race on volunteer helping relationships among the elderly.

As programs solicit their help in providing transportation, shopping assistance, telephone reassurance, counseling, and information and referral to needy elderly people, older adults are going to fill increasingly important roles as volunteers in the social service system for this aging society. Little empirical work has been done on effective volunteer behavior. This article aims to increase understanding of this topic by exploring how race influences relationships between volunteers and the people they serve. This analysis reveals that race by itself does not affect volunteer helping behavior; black and white older adults perform similarly in volunteer roles on measures of time committed to service and satisfaction levels of clients. However, the racial composition of the dyad does have significant effects on the helping relationship; higher levels of contact and client satisfaction are reported when the volunteer and the client are of the same race. Professional training and support are necessary to overcome problems associated with racial differences between volunteers and their clients.

Black or African American↗
PubMed1987

Successful intermittent chemoprophylaxis for Pneumocystis carinii pneumonitis.

We conducted a prospective, randomized clinical trial over a two-year period in patients with acute lymphocytic leukemia to assess the effectiveness of trimethoprim-sulfamethoxazole given on three consecutive days each week as compared with daily in the prevention of Pneumocystis carinii pneumonitis. P. carinii pneumonitis did not develop in any of 92 patients receiving the drug daily (30,602 patient-days) or in any of 74 who received it three consecutive days a week (27,329 patient-days), whereas the incidence of the infection expected without prophylaxis is 21 percent. One patient, excluded from both groups because of an adverse reaction to sulfonamides in the past, acquired P. carinii pneumonitis. Especially noteworthy was a difference in the occurrence of systemic mycoses, with 10 cases in the daily-treatment group and only 1 case in the three-days-a-week group (P = 0.024). No differences were observed in the rates of other infections or adverse effects associated with the drug. We conclude that trimethoprim-sulfamethoxazole is as effective given three days a week as it is given daily in the prevention of P. carinii pneumonitis and that the intermittent schedule has the advantages of less frequent fungal infections and lower cost. Intermittent chemoprophylaxis may be especially beneficial to certain patients who are unable to tolerate the daily doses.

Anti-Infective Agents↗
PubMed1987

Efficacy of benzathine penicillin G in group A streptococcal pharyngitis: reevaluation.

The rate of streptococcal eradication after intramuscular administration of benzathine penicillin G in 66 children with acute group A streptococcal pharyngitis was determined and possible reasons for treatment failure explored. Bacteriologic treatment failure, defined as isolation of the same serotype at 3- or 6-weeks follow-up, occurred in eight (12%) patients. The treatment failure rate was 21% in those with immunologically significant infection, versus 8% in those without antibody rises (P greater than 0.1). All group A beta-hemolytic streptococcal (GABS) strains isolated from patients with treatment failure, both before and after benzathine penicillin G therapy, were exquisitely susceptible to penicillin G (minimum inhibitory concentration less than or equal to 0.02 microgram/mL), and none showed evidence of tolerance (minimum bactericidal concentration less than or equal to 0.04 microgram/mL). Thus, we found GABS eradication rates to exceed 10% in children given benzathine penicillin G. The failure rate did not appear to be related to enrichment of the patient population with a high proportion of asymptomatic carriers nor to the presence of penicillin-tolerant GABS.

Child↗
PubMed1987

Induction of prostaglandin synthesis as the mechanism responsible for the chills and fever produced by infusing amphotericin B.

Amphotericin B produces chills and fever in a significant proportion of patients who receive this drug. The mechanism for this adverse effect is unknown. Amphotericin B suspension at a concentration of 1.0 microgram/ml was demonstrated to be a potent inducer of prostaglandin E2 synthesis by human and murine mononuclear cells in vitro. A double-blind, placebo-controlled clinical trial demonstrated that ibuprofen (10 mg/kg), a potent inhibitor of prostaglandin synthesis, administered 30 min before amphotericin B administration reduced the incidence of chilling from 87% to 49% (P = .01); the incidence of chilling reactions considered severe was reduced from 69% to 15% (P = .008). We postulate that the chills and fever produced by an infusion of amphotericin B are mediated through prostaglandin E2 synthesis. Ibuprofen is therapeutically useful in ameliorating the chills and fever caused by amphotericin B.

Adolescent↗
PubMed1987

Varicella in children with cancer: impact of antiviral therapy and prophylaxis.

To estimate the impact of antiviral therapy and prophylaxis on the natural course of the infection, 288 cases of varicella in children with cancer were reviewed. Among 127 patients with untreated infections, the overall mortality rate was 7%. Varicella-zoster virus pneumonitis developed in 28% of the untreated patients and was associated with a 25% mortality rate. Pneumonitis was much more likely to develop in patients with acute leukemia than in those with other malignancies (32% v 19%). Similarly, deaths due to pneumonitis were restricted to patients with acute leukemia. Lymphopenia (absolute lymphocyte count less than 500/microL) was significantly associated with varicella-zoster virus pneumonitis and a higher fatality rate among patients with this complication. Both acyclovir and adenine arabinoside, administered to 18 and 28 patients, respectively, stopped the progression of skin lesions; however, pneumonitis developed in none of the acyclovir recipients after two days of treatment, compared with 29% of the adenine arabinoside recipients (P = .03). Passive immunization in 45 children who subsequently had varicella was associated with an 11% incidence of varicella-zoster virus pneumonitis. Despite passive immunization of approximately 150 children, the attack rate of varicella at our institution remains unchanged. Results of this study demonstrate the efficacy of antiviral therapy and passive immunization in patients with childhood cancer and varicella, but prevention of the infection will require a universal vaccine.

Antiviral Agents↗
PubMed1985

Similar hematologic changes in children receiving trimethoprim-sulfamethoxazole or amoxicillin for otitis media.

We report the hematologic changes in 90 black children who were randomized to receive a 10-day course of either trimethoprim-sulfamethoxazole (TMP-SMZ) or amoxicillin as therapy for acute otitis media. Absolute neutrophil counts less than 1500/mm3 developed at least once during the 23-day evaluation in 28 (57%) of the 49 children given TMP-SMZ and in 22 (54%) of the 41 who received amoxicillin. Incidence of leukopenia, thrombocytopenia, and anemia was negligible in both groups. Pancytopenia did not occur in any child. Absolute neutrophil counts had increased to greater than 1500/mm3 by the end of the study period in all of the patients but six, whose recovery required an additional 1 to 63 days. Decreased neutrophil counts in antibiotic-treated subjects remained within the range of findings for healthy black children, suggesting that a count less than 1500/mm3 may be an inappropriate criterion for an adverse drug effect. Neither TMP-SMZ nor amoxicillin produced hematologic effects that would detract from their continued use in children with infections caused by antibiotic-susceptible organisms.

Amoxicillin↗
PubMed1985

Memory-skills training, memory complaints, and depression in older adults.

This study examined the effectiveness of a self-taught program of memory-skills training for older adults complaining of memory difficulties in an immediate-treatment/waiting-list design. Analyses of covariance of measures of memory performance, memory evaluation (complaints), and a self-rating depression scale revealed a significant impact of training on memory performance but not on memory complaints or symptoms of depression. Subsequent evaluation of the waiting-list group, which was provided training after participation in the initial portion of the study, provided a partial replication of the design. The pattern of results was remarkably consistent with that obtained in the controlled evaluation of the training program. Finally, those complaining of memory problems were compared with a group of noncomplaining older adults. The two groups were comparable in memory performance and depression scores. Thus, memory complaints do not appear to reflect, systematically, memory problems or depression.

Aged↗
PubMed1985

Detection of fever with infrared thermometry: a feasibility study.

Fever is a remarkably sensitive indicator of infectious disease. The thermometer in clinical use today is basically that developed over a century ago, measuring heat conducted from skin or mucous membranes to an adjacent probe. In dealing with immunosuppressed granulocytopenic patients, the need was realized for an instrument by which temperature might be determined without a probe contact. Infrared pyrometers have been used in industry to record the temperature of mechanical objects at a distance. We tested the feasibility of using such an instrument to detect fever in humans. In a controlled and blinded fashion, infrared measurements from the eyes, axillae, and areas below the ear lobes (E spot) of 140 febrile and afebrile patients were compared with rectal temperatures recorded by a standard thermometer. The eye and E spot provided the most accurate readings. Infrared measurements of the right eye identified 57 (95%) of 60 febrile and 72 (90%) of 80 afebrile patients correctly. Overall, 92% of all patients were correctly categorized by use of the infrared thermometer at this site. We conclude that this approach is feasible and, with further technical developments, may be applicable for routine clinical use.

Child↗
PubMed1985

Use of influenza A virus vaccines in seronegative children: live cold-adapted versus inactivated whole virus.

We report the safety and antigenicity of influenza A vaccines in seronegative children one to seven years of age. A natural H1N1 challenge that occurred shortly after completion of the vaccination program permitted an evaluation of efficacy. Twenty-eight subjects were inoculated with live cold-adapted (ca) influenza A/Washington/897/80 (H3N2), 29 with ca influenza A/California/10/78 (H1N1), 24 with inactivated whole-virus influenza A/Bangkok/79 (H3N2), and 30 with a placebo. The ca vaccines were well tolerated, whereas the inactivated vaccine caused adverse reactions in about one-third of the children. Fifty-seven percent of the ca H1N1 recipients showed serological responses, contrasted with 84% and 100% of subjects receiving the ca or inactivated H3N2 vaccines, respectively. None of the 16 children with induced H1N1 antibody developed clinically apparent influenza-like illness, compared with eleven of the 51 initially seronegative children who did not receive the ca H1N1 vaccine and with four of the 12 who failed to respond. Results of the efficacy field trial suggest protection against infection and symptomatic illness in children inoculated with ca H1N1, despite its failure to stimulate high levels of hemagglutinin-inhibiting antibody.

Antibodies, Viral↗