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Biomedical subjects

N Strauss

Publications and source records attributed to N Strauss.

At least 19 recordsLinked to original sources
PubMed2001

Distribution of blood lead levels in schoolchildren in selected Cape Peninsula suburbs subsequent to reductions in petrol lead.

OBJECTIVE: To determine blood lead levels among children attending schools in selected Cape Peninsula suburbs, and to assess the impact of a reduction in the lead content of petrol. DESIGN: A cross-sectional analytical study of children's blood lead levels and associated risk factors. SETTING: Selected inner city, suburban, and peri-urban schools in the Cape Peninsula, expected to have differing levels of environmental exposure to lead. SUBJECTS: Grade 1 schoolchildren for whom prior written parental consent had been obtained, and who were present at school on the day of the study. OUTCOME MEASURES: Blood lead levels (microgram/dl), associated with a wide range of potential risk factors. RESULTS: Median blood lead levels in suburbs varied from 14 to 16 micrograms/dl, the lowest levels occurring in the peri-urban suburb and the highest in the inner city suburb. Within the inner city suburb of Woodstock, variations in mean blood lead concentrations among schools were substantial, varying from 13 to 19 micrograms/dl. Overall, no change occurred in blood lead levels in this suburb subsequent to the lowering of the lead content of petrol. CONCLUSION: Every effort should be made in South Africa to control sources of lead in the urban environment. The study will serve as a useful baseline against which to measure the impact on blood lead levels of further actions which have been taken to promote the use of lead-free petrol in South Africa.

Child↗
PubMed1999

Engraftment of marrow allografts treated with Campath-1 monoclonal antibodies.

We have analyzed the factors associated with engraftment in 216 recipients of T-cell depleted allogeneic HLA identical sibling marrow transplants using Campath 1 monoclonal antihuman lymphocyte (CD52) antibodies. The patient population consisted of 168 patients with hematologic malignancies, 26 with severe aplastic anemia (SAA), and 22 with hemoglobinopathies, half of whom received marrow treated in vitro with Campath-1M (IgM) and half received marrow with Campath-1G (IgG2b isotype). Patients with durable engraftment had fast hematopoietic recovery: SAA patients reached ANC > 0.5 x 10(6)/L on Day 14; those with leukemia attained ANC > 0.5 x 10(6)/L on Days 18, 17, and 15 for ANLL, ALL and CML respectively, while patients with thalasemia reached ANC > 0.5 x 10(6)/L on Day 21. Overall, 24 patients (17 with leukemia, 4 with SAA, and 3 with thalassemia) suffered graft failure: 10 patients (all grafted with Campath-1M) rejected their grafts, while 14 others (9 grafted with Campath-1M, and 5 with 1G isotype) never engrafted (p = 0.009). Multivariate analysis revealed that neither pretransplant protocol, nor stage of disease or type of antibody used, donor sex and ABO match had any impact on engraftment. The variables favorably associated with engraftment were older age (p = 0.030, RR = 1.016) and CFU-GM number (p = 0.013, RR = 1.001). Patients with ANLL or SAA had a better chance to engraft (p = 0.027, RR = 1.400; and p = 0.003, RR = 2.677, respectively) compared to patients with thalassemia (p = 0.001, RR = 0.551). A higher concentration of Campath-1 antibody in vitro and in vivo adversely affected engraftment. Our data show that satisfactory engraftment can be achieved in patients transplanted with Campath-1 treated marrow allografts. However, despite the measures undertaken to prevent rejection, graft failure still poses a problem. Further pretransplant immunosuppression and perhaps more selective T-cell depletion may reduce the increased graft failure in these patients.

ABO Blood-Group System↗
PubMed1998

Nosocomial colonization, septicemia, and Hickman/Broviac catheter-related infections in bone marrow transplant recipients. A 5-year prospective study.

In this 5-year prospective study of 242 bone marrow transplantation (BMT) recipients from whom daily blood cultures via the indwelling Broviac/Hickman catheter were obtained, there was a median of 35 catheter-days during hospitalization, mean of 40 days, and total of 9,667 catheter-days which were divided almost equally between neutropenic (4,771) and non-neutropenic (4,896) days. One hundred twenty (50%) patients had a total of 161 episodes of nosocomial bacterial or candidal infections. Overall, 81 (33%) patients experienced 100 episodes of catheter-related infections and 90 (37%) patients experienced 112 episodes of septicemia, including 51 episodes of catheter-related septicemia. There was an incidence of 11.59 septicemia episodes, including 5.28 catheter-related septicemia episodes, 2.48 colonization only (without subsequent septicemia), and 2.59 exit site infections only, per 1,000 catheter-days. Over a period of a total of 6,593 afebrile days, 34 (14%) patients developed 40 episodes of colonization, a rate of 6.07 per 1,000 afebrile days, of which 16 developed into septicemia. Twenty-five patients had 1 episode each of exit site infection without bacteremia. There were 10 (4%) septicemia-related deaths, 4 of which were catheter-related; 50% of all deaths involved Pseudomonas aeruginosa. The mortality due to catheter-related septicemic episodes was not greater than that of the non-catheter-related episodes. Neutropenia was found to be a significant risk factor in our study: 76% of the septicemia episodes (85/112) and 65% of the catheter-related infectious episodes (65/100) occurred during neutropenia. There was a higher incidence of septicemic episodes during neutropenia than during non-neutropenic periods, 17.82 versus 5.51 per 1,000 days (p < 0.0001), and a higher rate of catheter-related infections during the neutropenic period, 13.62 versus 7.15 during non-neutropenic days per 1,000 days (0.001). Fourteen of 16 colonization episodes developed into septicemia during neutropenia versus 2/24 during non-neutropenic periods, a rate of 5.47 versus 0.47 per 1,000 afebrile days, respectively (p < 0.0001), and 9/10 deaths occurred during neutropenia.

Adolescent↗
PubMed1997

Antibody response to influenza immunization in patients after heart transplantation.

The aim of this study was to evaluate post-heart transplantation (Htx) response to two-dose and three-dose influenza vaccine. Hemagglutination inhibition antibodies were monitored in HTx recipients immunized twice (n = 25) or three times (n = 17), and non-HTx controls (n = 8) once, with inactivated influenza vaccine. Post-first dose protective antibody titers (> or = 1:40) were demonstrated in 9/25 (36%) for A/Singapore/ (H1N1), 5/25 (20%) for A/Shanghai/(H3N2) and 2/25 (8%) for B/Yamagata compared with 4/8 (50%), 6/8 (75%) and 2/8 (25%), respectively, for controls. Post-second dose protective titers remained low, increasing following the third dose to 71%, 65% and 29%, respectively. The abnormally low antibody responses of HTx recipients to one-dose and two-dose influenza vaccine can be overcome by a third dose.

Adolescent↗
PubMed1997

Serotype-related differences in inflammatory response to Streptococcus pneumoniae in experimental meningitis.

It has been suggested that serotype influences severity of experimental pneumococcal meningitis. This hypothesis was tested with strains of serotypes 1, 5, 6B, 7F, 14, and 23F, prevalent in Israel, in an experimental rabbit model. Cerebrospinal fluid (CSF) bacterial titers, leukocyte densities, concentrations of lactate, protein, and glucose, tumor necrosis factor-alpha levels, brain water content, and cerebral blood flow were measured 18 h after inoculation of pneumococci. Serotypes 5 and 7F exhibited mild inflammatory responses (leukocytosis <1000/mm3, lactate <4 mmol/L); types 6B, 14, and 23F showed severe inflammatory responses (leukocytosis >5000/mm3, lactate >10 mmol/L); serotype 1 had intermediate inflammatory responses but exceptionally high CSF bacterial titers. Leukocyte count correlated with all other variables; lactate with all except brain water content. On the basis of 6 Streptococcus pneumoniae serotypes, three discrete levels of inflammatory responses could be delineated in experimental pneumococcal meningitis.

Animals↗
PubMed1997

Editorial.

Explore the source record for details and available documents.

Africa↗
PubMed1996

Nosocomial coagulase-negative staphylococcal infections in bone marrow transplantation recipients with central vein catheter. A 5-year prospective study.

The purpose of this study was to examine coagulase-negative staphylococcal infections in bone marrow transplantation (BMT) patients with central vein catheters by investigating incidence, clinical relevance, risk factors, methicillin resistance, clinical impact of initial empiric antimicrobial therapy without vancomycin, and management of documented catheter-related infections. A 5-year prospective study was conducted with daily evaluation of 242 BMT patients during hospitalization, including clinical assessment and blood culture via the Hickman/Broviac catheter. If fever or infected appearance occurred, peripheral blood cultures or exit site cultures, respectively, were done. Results showed a septicemia incidence of 7.0%, including in 6 patients following colonization, in 1 patient with tunnel infection, in 1 patient with thrombophlebitis, in 1 patient with exit site infection, and in 8 patients with septicemia of unknown origin. Total colonization incidence was 7%, with colonization only in 11 patients who had 16 episodes; incidence of exit site infection was 3.7%. Age > or = 18 years was the only identified risk factor for developing staphylococcal infection (P = 0.03). Despite a methicillin resistance rate of 45% and omission of vancomycin from the routine initial empiric antimicrobial regimen, the clinical course of coagulase-negative staphylococcal infections was relatively benign. A single patient, who experienced marrow rejection, died on day +31 with septicemia and only one patient experienced microbiological failure with recurrent colonization. Bacteria grown in both aerobic and anaerobic bottles were more likely true bacteremia than contaminant (P = 0.03). We conclude that the hazard of coagulase-negative staphylococcal infection does not mandate inclusion of a glycopeptide in the initial empiric antimicrobial regimen in BMT patients, even during febrile neutropenia. Hickman/Broviac-related staphylococcal infections, except for tunnel infection or thrombophlebitis, can usually be treated successfully without removing the catheter.

Adolescent↗
PubMed1995

Bacterial pneumonia in recipients of bone marrow transplantation. A five-year prospective study.

Bacterial pneumonia as an important complication of bone marrow transplantation (BMT) has not been subjected to comprehensive analysis. Two hundred fifty-five consecutive allogeneic and autologous BMT recipients, ranging in age from 1 month to 53 years, were prospectively followed for 3 days to 3 years (median, 108 days) for development of bacterial pneumonia. Etiology, place acquired, chest radiography, and outcome were recorded and the association between bacterial pneumonia and demographic and clinical variables was analyzed. Thirty-seven (15%) patients experienced 52 episodes of bacterial pneumonia: onset of 13 episodes occurred within 30 days after transplantation, 10 episodes occurred on days +31 to +100, and 29 episodes occurred thereafter. Bacterial pneumonia was the terminal event or contributed to fatal outcome in 8 patients (22% of bacterial pneumonia cases, 3% total study population). Mortality due to hospital-acquired pneumonia (6/21) was significantly higher than (P = 0.03). Bacterial pathogens were identified in 27 (52%) episodes. During the first 100 days after BMT, hospital-acquired Gram-negative bacteria predominated, caused mainly by Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter lwoffi, and Enterobacter cloacae. After day +100, community-acquired, Gram-positive bacteria predominated, particularly Streptococcus pneumoniae. Haemophilus influenzae occurred periodically. Considering all episodes, significant association was found between bacterial pneumonia and veno-occlusive disease (VOD) (P < 0.01) and chronic graft-versus-host disease (GVHD) (P < 0.02). For culture-positive episodes, the association between bacterial pneumonia and VOD was significant (P < 0.001) and borderline for acute GVHD (P = 0.07). It is concluded that VOD and GVHD are positively associated with post-BMT bacterial pneumonia. Its incidence, etiology, risk factors, and outcome are important considerations in its prevention and treatment.

Adolescent↗
PubMed1995

Investigating a sequence of randomized phase II trials to discover promising treatments.

We consider clinical trial strategies to study diseases in which there is rapidly developing technology. We assume the availability of a limited number of patients for screening treatments over a time horizon, and that availability of new treatments for test is staggered over time. We assume further that patient response is binary and rapidly observable. We consider the strategy of conducting a sequence of two-armed randomized clinical trials. We carry over the treatment with the larger number of observed successes on the current trial to the next trial for comparison with a new treatment, with this process repeated at each step. For a fixed total number of patients (N), the number of trials one may conduct in sequence (k) is inversely related to the sample size per trial (2n), N = 2nk. We investigate how k and n influence (a) the expected success probability for the treatment selected at the end, and (b) the expected number of total successes for the N patients. The ultimate objective is to select one treatment, the winner at stage k, to test against a standard regimen in a randomized comparative phase III trial.

Clinical Trials, Phase II as Topic↗
PubMed1995

Comparison between nafarelin acetate and D-Trp6-LHRH for temporary pituitary suppression in in vitro fertilization (IVF) patients: a prospective crossover study.

PURPOSE: Nafarelin acetate is a new gonadotropin releasing (GnRH) agonist analogue with unique potency, intranasal administration, and convenient storage. Hence, nafarelin was considered as an alternative for temporary pituitary suppression in patients undergoing ovulation induction in IVF. A crossover treatment in a prospective study was performed including 40 women with bilateral obstructed tubes and normal ovarian function, treated in 80 ovulation induction cycles using the long protocol. Twenty patients used nafarelin acetate 600 micrograms/daily in their first cycle and received D-Trp6-LHRH, 0.5 mg/daily, in their following cycle. The other 20 women used decapeptyl in their cycle and received nafarelin in the second. RESULTS: Estradiol suppression was achieved by both D-Trp6-LHRH and nafarelin at equal time intervals. The average total number of ampoules (P = 0.0005) and the length of administration of hMG required for ovarian stimulation (P = 0.0002) and the time interval between GnRHa initiation to oocyte retrieval (P = 0.04) was significantly lower in nafarelin cycles. The number and the distribution between large and small follicles as well as the average number of oocytes retrieved did not differ between the two GnRH analogues. CONCLUSION: Our results demonstrate that nafarelin acetate is comparable to D-Trp6-LHRH for temporary pituitary suppression used for controlled ovarian stimulation in IVF patients. However, using nafarelin ovarian stimulation was achieved with few ampoules of hMG, administered for a shorter period of time, thus with a lesser cost.

Adult↗
PubMed1995

Cytosine arabinoside as a major risk factor for Streptococcus viridans septicemia following bone marrow transplantation: a 5-year prospective study.

The incidence and clinical course of nosocomial septicemia with Streptococcus viridans was evaluated prospectively in 242 consecutive bone marrow transplant (BMT) recipients throughout their 15-213 days' (median 47) hospitalization, including 4-58 days (median 18) of neutropenia. Initial empiric therapy for febrile neutropenia consisted of mezlocillin, gentamicin and cefazolin; glycopeptide was excluded. S. viridans septicemia occurred in 23/209 (11%) subjects with underlying malignant disease, and only during neutropenia with concomitant mucositis: in 20 subjects (four with ampicillin-resistant strains), S. viridans septicemia occurred at onset of febrile neutropenia, 1-5 days (median 4.5) post-BMT. All survived with an uncomplicated clinical course. Thus, glycopeptide seems unnecessary in the initial empiric antibiotic regimen. The other three subjects demonstrated S. viridans septicemia (two with ampicillin-resistant strains) on day 11 post-BMT; two died. The major risk identified was cytosine arabinoside administration in the conditioning regimen (P < 0.01).

Adolescent↗
PubMed1993

Antibody response to a two-dose regimen of influenza vaccine in allogeneic T cell-depleted and autologous BMT recipients.

Induction of protective hemagglutination-inhibition (HI) antibodies in response to influenza virus vaccine and the effectiveness of two doses versus a single dose of vaccine were studied in 48 BMT recipients. The patients were 1-50 years old (median 21 years), 33 with malignant and 15 with non-malignant disease. Thirty-five of the patients underwent allogeneic, T lymphocyte-depleted, BMT and 13, autologous BMT. Nine patients had GVHD at initial immunization. The time interval from BMT to influenza vaccination ranged from 2 to 82 months (median 14.5 months). Two doses of vaccine, administered 1 month apart, consisted of trivalent influenza subunit inactivated vaccine with the following strains: A/Singapore/6/86 (H1N1), A/Sichuan/2/87 (H3N2), and B/Beijing/1/87. There was a statistically significant association between development of protective antibody level (> or = 1:40) and the time interval between BMT and initial vaccination (p < or = 0.001). Regression analysis revealed that longer time interval between the BMT and immunization was positively correlated with seroconversion (a fourfold or greater rise in titers). In the presence of GVHD, there was reduced seroconversion to H1N1, but not to H3N2 or B strains. Influenza vaccination within the first 6 months following BMT was totally ineffective. The efficacy of the vaccine was similar to that described in non-immunocompromised hosts initiated 2 years following BMT. As, overall, specific response was only marginally enhanced by the second dose of vaccine, its indication is questionable.

Adolescent↗
PubMed1992

Mean corpuscular volume of heterozygotes for beta-thalassemia correlates with the severity of mutations.

The relationship between the degree of microcytosis and the type of mutation carried by beta-thalassemia heterozygotes was investigated. In 113 individuals, 18 different mutations were identified, correlated with mean corpuscular volume (MCV) values, and analyzed statistically. Overall, there was a wide range of MCV (56.3-87.3 fL). In almost all cases, carriers of beta(0) mutations had an MCV below 67 fL, whereas all but a few beta(+) heterozygotes had MCVs above this cutpoint. Mean MCV of beta(0) carriers was statistically significantly lower than those of beta(+) heterozygotes. The various beta(+) mutations were associated with significant differences in mean MCV values. In contrast, all the beta(0) (null) mutations had virtually identical ranges of MCV. The results indicate that degree of reduction in MCV is directly related to the severity of the mutation. Deviations, in four cases, were associated with concurrent alpha gene rearrangements, whereas in three other cases, the MCV was not significantly affected by concurrent alpha rearrangements. The MCV of beta-thalassemia heterozygotes is a valuable parameter in planning strategies for rapid identification of mutations in populations with great mutational diversity. Its use can be particularly advantageous in the setting of prenatal diagnosis. The pattern of mean corpuscular hemoglobin (MCH) values was similar to the MCV pattern. However, our results suggest that MCH may be preferred for carrier detection in population screening.

Erythrocyte Indices↗
PubMed1992

Methylprednisolone as antiemetic treatment in breast-cancer patients receiving cyclophosphamide, methotrexate, and 5-fluorouracil: a prospective, crossover, randomized blind study comparing two different dose schedules.

The antiemetic response and side effects resulting from treatment with methylprednisolone (MPA) given on two different dose schedules were evaluated in 20 women with breast cancer who were undergoing chemotherapy consisting of cyclophosphamide, methotrexate and 5-fluorouracil (CMF). This randomized, crossover, double-blind study compared the antiemetic efficacy of a single dose of 125 mg MPN with that of two such doses. The study demonstrated the superiority of the latter protocol in preventing CMF-induced nausea and vomiting. The rate of antiemetic response to single vs double doses was as to follows: complete protection, 17% vs 30%; partial and minimal protection, 39% vs 55%; and no protection, 44% vs 15% of the courses, respectively (P = 0.0087). No difference in the antiemetic response rate was found between the first and the second course. Treatment with MPN was well tolerated, and no difference in the incidence of side effects was found between the single-dose and the double-dose schedule. We recommend the use of two doses of 125 mg MPN as prophylactic antiemetic treatment in breast-cancer patients receiving CMF chemotherapy.

Adult↗
PubMed1991

Incidence of spontaneous and evoked fetal movements in the first half of twin pregnancy.

Fetal movements (FM) may be spontaneous, originating in the fetus itself, or evoked, caused by external stimuli. The FM in 21 normal twin pregnancies at 10 and 21 weeks of gestation were studied. The percentage rate of evoked FM which occur simultaneously in both twins was 4.96% of all observed FM. The rate of the spontaneous FM which occur independently in each fetus was 95.04% of all FM. The low incidence of evoked FM, at an early gestational age (10-21 weeks) emphasizes the ability of these young fetuses to perceive external stimuli and to react to them by FM.

Female↗