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Biomedical subjects

D Otto

Publications and source records attributed to D Otto.

At least 55 records · Page 3Linked to original sources
PubMed1986

Relation of lead and social factors to IQ of low-SES children: a partial replication.

An independent replication of a previous study (Schroeder et al., 1985) of the effects of interactive social environmental factors on the relationship of lead and Stanford-Binet IQ was performed on 75 of 80 low-SES black children screened by county health departments in North Carolina. Children's mean blood lead (PbB) level was 20.8 micrograms/dl (range, 6.3 to 47.4). Multivariate regression analyses showed no significant interactions between PbB and age, sex, maternal IQ, Caldwell home environment score, or SES (Hollingshead Two-Factor Index). There was a highly significant negative relationship between both mean and maximum PbB levels with IQ, p less than .002; that is, IQ decreased linearly as PbB increased. The most accurate and precise regression model included lead, maternal IQ, home environment, and gender.

Child↗
PubMed1985

5-year follow-up study of children with low-to-moderate lead absorption: electrophysiological evaluation.

Forty-nine children aged 6 to 12 years were evaluated for residual effects of lead exposure using psychometric, electrophysiological, and medical tests 5 years after initial assessment. The original range of blood lead (PbB) levels was 6-59 (mean = 28) micrograms/dl; the current range was 6-30 (mean = 14) micrograms/dl. A linear relationship between PbB and slow brain wave voltage during sensory conditioning was observed at initial evaluation and at 2-year follow-up. No significant relationship between PbB and slow wave voltage during passive conditioning was found at the 5-year follow-up, although a linear increase in slow wave negativity relative to the current PbB level during active conditioning was suggested by exploratory analyses. Another exploratory analysis revealed a significant linear relationship between the original PbB levels and the latency of waves III and V of the brainstem auditory evoked potential. The latency of both waves increased as a function of original PbB. Increased latency of these waves is suggestive of subclinical pathology of the auditory pathway rostral to the cochlear nucleus, although end-organ impairment cannot be ruled out. No threshold for the effect of Pb on auditory function was apparent.

Brain↗
PubMed1985

Abnormal clonogenic potential of T cells from multiple myeloma patients.

Peripheral blood lymphocytes (PBLs) from multiple myeloma patients are defective in both proportion and absolute numbers of OKT4+ cells and have a normal proportion but reduced absolute number of OKT8+ cells. To assess the functional capabilities of the T cells in myeloma patients, we cloned the T cells in PBLs using limiting dilution conditions in which 100% of OKT4+ and OKT8+ T cells in normal PBLs are able to form a clone. In contrast, the OKT8+ cells from PBLs of five of seven multiple myeloma patients were severely compromised in their clonogenic potential; only 7% to 25% of OKT8+ T cells appeared to give rise to a clone. Clonogenic potential of the OKT4+ cells in patients was more nearly normal. Analysis of two multiple myeloma patients with abnormally low numbers of T cells in PBLs revealed the existence of abnormalities in the progenitors of T cell clones. In both patients, two to three times as many T cell clones were observed as would have been expected based on the number of PBLs cultured at limiting dilution, indicating that OKT4-8- cells in PBLs are capable of giving rise to OKT4+ and, at lower frequency, to OKT8+ clonal progeny in vitro. We conclude that purely quantitative assessment of T cell subsets should be interpreted with caution, since proportionately normal numbers of OKT8+ cells in patient PBLs are seriously compromised in their ability to give rise to clonal progeny in vitro, and since there appears to be a OKT4-8- population of T cells in PBLs that are committed to become OKT4+ or OKT8+ T cells, but are unable to do so in vivo.

Antibodies, Monoclonal↗
PubMed1984

Developmental changes in slow cortical potentials of young children with elevated body lead burden. Neurophysiological considerations.

The effects of age and blood lead level (PbB) on slow cortical potentials elicited during classical conditioning were studied in children aged 13 to 75 months. At normal PbB levels (less than 30 micrograms/dl), SW voltage tended to be positive in children under five years old and negative in children over five years. A reverse age-related polarity shift was observed in children with elevated PbB levels (Otto et al., 1981). Evidence indicative of excitatory (or disinhibitory) effects of Pb exposure in immature animals (associated with hyperactivity in animals and children) was reviewed. Reversals in locomotor activity (hypoactivity) and electroconvulsive activity have also been noted in adult animals exposed to Pb as pups. Neurophysiological evidence suggests that slow surface-positive potentials in very young children may reflect axodendritic inhibitory processes. As the cortex matures, the locus of inhibitory activity shifts deeper to axosomatic connections. Negative slow potentials observed in older children, therefore, are presumed to reflect the surface negative (dendritic depolarization), depth positive (somatic hyperpolarization) dipole hypothesized by McSherry (1973) as the neurophysiological substrate of the CNV. Although the developmental model of the CNV proposed here is based on preliminary data and is clearly speculative, the implications of the model and data merit consideration. Positive shifts observed in very young children during the CS-UCS interval suggest why previous investigators have had great difficulty in eliciting contingent negative variation in subjects younger than five years. The data also suggest that body Pb burden at any level produces an observable effect on CNS function. Further study is needed to replicate and clarify these findings.

Cerebral Cortex↗
PubMed1975

[Immunization experiments for producing antibody-like substances in caterpillars of Mamestra brassicae L. (Insecta, Lepid., Noct.)].

The agglutinins against human blood cells described in caterpillars of Mamestra brassicae L. were not demonstrable when feeding the animals with a semisynthetic food. After injection or oral intake of certain bacteria (E. coli or streptococci of group C) or even Pope's broth the "antibody-like substances" known from feeding with natural food are being formed, and they agglutinated all human blood cells. The individual animals showed differences regarding the strength of agglutinin formation. The immune reactions observed possibly indicate the existence of a primitive immune system in these species (arthropods).

Agglutination↗
PubMedDate not supplied

Neurobehavioral and sensory irritant effects of controlled exposure to a complex mixture of volatile organic compounds.

Subjective reactions of discomfort, impaired air quality, irritation of mucosal membranes, and impaired memory have been reported in chemically sensitive subjects during exposure to volatile organic compounds (VOCs) found in new buildings. Sixty-six normal healthy male subjects aged 18-39 were exposed for 2.75 hr to a complex VOC mixture at 0 and 25 mg/m3. Each subject completed control and exposure sessions at one-week intervals in counterbalanced order. Measurements included comfort ratings of eye, nose and throat irritation, symptom questionnaire and computerized behavioral tests. Subjects found the odor of VOCs unpleasantly strong and reported that VOC exposure degraded air quality, increased headache and produced general discomfort. VOC exposure did not affect performance on any behavioral tests.

Adult↗
PubMedDate not supplied

Blood lead, hearing thresholds, and neurobehavioral development in children and youth.

NHANES II audiometry data were used to confirm a previously observed link between blood lead (PbB) level and hearing threshold. Other indicators of neurological development, such as age at which a child first sat up, walked, and spoke, and the presence of speech difficulties and hyperactivity were also examined to determine if they were significantly related to lead exposure. The probability of elevated hearing thresholds at 500, 1000, 2000 and 4000 Hz increased significantly (p less than .0001) with increasing PbB for both ears. PbB levels were also significantly related to delays in the age at which children first sat up, walked, and spoke and to the probability that a child was hyperactive. Lead was not related to the probability of a child having a previously diagnosed speech impairment.

Child Development↗
PubMedDate not supplied

Lead and minor hearing impairment.

We examined data recorded for 3,545 subjects aged 6-19 y who participated in the Hispanic Health and Nutrition Survey. We sought to confirm a relationship between blood lead levels and elevated hearing thresholds that we previously reported in a similar study in which data from the Second National Health and Nutrition Examination Survey was used. Lead was associated with an increased risk of hearing thresholds that were elevated above the standard reference level at all four frequencies (i.e., 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz). Lead was also associated with hearing thresholds when they were treated as a continuous outcome. The relationships appeared to continue at blood lead levels less than 10 micrograms/dl. An increase in blood lead, from 6 micrograms/dl to 18 micrograms/dl, was associated with a 2-dB loss in hearing at all frequencies, and an additional 15% of children had hearing thresholds that were below the standard at 2,000 Hz.

Adolescent↗
PubMedDate not supplied

Influence of ascites on the chemotaxis of granulocytes in patients with cirrhosis.

Spontaneous bacterial peritonitis is a specific infectious complication in liver cirrhosis. The reasons for the preferred location of infection on the peritoneum are not clear. The aims of the present study were to ascertain whether hepatogenic ascites fluid is chemotactically effective, what part is played by complement factor C3 and whether there are inhibitors of chemotaxis in ascites. Chemotaxis of granulocytes in serum and ascites fluid was measured in 18 patients with cirrhosis and ascites and in 18 healthy individuals using the Boyden chamber method. In the patients, the chemotactic effect of serum was reduced significantly. Ascites fluid had lower chemotactic activity than autologous serum (P < 0.01), directly correlated to C3 levels (P < 0.025). There was a significant correlation between chemotaxis in serum and in ascites fluid (P < 0.005). Adding ascites fluid to serum led to reduction of chemotactic activity only in the patients (P < 0.025). In conclusion, the chemotactic effect of ascites fluid is considerably lower than that of serum and is proportional to local concentrations of C3. Chemotaxis-inhibiting factors can also be identified in ascites fluid, their pathogenetic relevance being limited.

Adult↗
PubMedDate not supplied

Five-year results of single-incision arthroscopic anterior cruciate ligament reconstruction with patellar tendon autograft.

We performed a retrospective study on 80 patients who underwent single-incision arthroscopic anterior cruciate ligament reconstruction with patellar tendon autograft and interference fit screw fixation in 1989. Twelve patients were lost to followup, allowing a clinical assessment of 68 patients to be conducted by independent examiners at 1 and 5 years after surgery, with radiographic assessment at 5 years. Thirty-three patients had chronic anterior cruciate ligament-deficient knees. Three patients reruptured their grafts during sports at 29, 48, and 56 months. At 5 years, 64 patients (98%) had grade 0 or 1 Lachman and pivot shift tests with manual stability testing. Fifty patients (77%) were participating in level I or II activities according to the International Knee Documentation Committee scale. Twenty-nine patients (45%) experienced low levels of pain when performing at their highest activity level. Five (8%) had thigh atrophy greater than 1 cm, and three (5%) had an extension loss of more than 3 degrees. Eleven patients (17%) had tenderness over the graft site when kneeling. Fifteen of 62 patients (24%) had degenerative changes on radiographs, and this was more common in patients with chronic anterior cruciate ligament-deficient knees. Fifty-two patients (80%) had normal or nearly normal knees according to the overall International Knee Documentation Committee score.

Adolescent↗