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Biomedical subjects

B Weiss

Publications and source records attributed to B Weiss.

At least 271 records · Page 15Linked to original sources
PubMed1984

Familial contexts of adolescent ego development.

In this paper we describe our newly constructed Constraining and Enabling Coding System (CECS). This scheme was constructed to identify family interactions that are conceptually relevant to adolescent ego development. First, we discuss the theoretical rationale and reliability properties of the codes. We then present results of applying the scales to observations of 61 families, consisting of 2 parents and an adolescent, drawn from matched high school and psychiatric populations. All families are upper and (predominantly) upper-middle class. Each member completed the Loevinger Sentence Completion Test and then participated in a revealed-differences task, using responses to Kohlberg Moral Dilemmas as discussion stimuli. Transcripts of these audiorecorded discussions formed the data base for the family analyses. After controlling for patient status and adolescent age, adolescent and parent ego-development scores still contributed to explained variance in family interactions. Adolescent ego development was positively associated with adolescent enabling behaviors (e.g., problem solving, empathy). In contrast, there were negative correlations between constraining behaviors (e.g., devaluing, withholding) and adolescent ego development. Parental behaviors were significantly associated with (a) parent ego development, and (b) adolescent ego development. The third dimension of our system, discourse change, also showed theoretically expected strong correlations between progressive discourse change and ego development. In our discussion we comment on the importance of now proceeding to sequence analyses in order to explore questions of directionality.

Adolescent↗
PubMed1983

[Resumption of work after the lst myocardial infarct. Results of the Hamburg Infarct After-Care Study].

In a prospective study of 1019 unselected patients, 53% of those under 60 years of age were again able to work within 18 months after the first myocardial infarction. Decisive for the high proportion of those who did not take up work again are, in particular, marked changes in the attitude towards work and the deteriorating employment situation, in addition to medical reasons such as cardiac complications (11.4%) and bypass operations (10%). The sociological changes weakened the positive effect of post-hospital treatment and rehabilitation, so that there has been no proven increase in the number of those returning to work, compared with data collected in the 1960s. Resumption of work can only conditionally be used as an indicator of success within a comprehensive rehabilitation plan.

Aged↗
PubMed1983

Inhibition of calmodulin activity by insect venom peptides.

Several peptides found in insect venom, including melittin, apamin and mastoparan, inhibited the activity of calmodulin-stimulated phosphodiesterase at concentrations that had no appreciable effect on basal phosphodiesterase activity; the Ki value of melittin for inhibiting calmodulin activity was 30 nM. Acetylation of the peptides reduced their inhibitory effect on calmodulin, suggesting that a net positive charge was an important determinant of anti-calmodulin activity. An examination of other structural features of these peptides suggested that the most potent inhibitors of calmodulin had an alpha-helical conformation. Equilibrium dialysis experiments showed that melittin inhibited the calcium-dependent binding of 3H-chlorpromazine to calmodulin (IC50 0.9 microM); kinetic analyses of these data indicated that this inhibition was non-competitive, suggesting that melittin and chlorpromazine act at different sites on calmodulin. Since calmodulin regulates a number of processes that these peptides inhibit, our results raise the possibility that the inhibition of calmodulin activity by these insect venom peptides may explain some of their biochemical or toxicological effects.

Animals↗
PubMed1983

[Heart infarction in persons over 70. Epidemiologic studies of the clinical course].

1158 patients with acute myocardial infarction hospitalized in 6 clinics at Hamburg were analyzed retrospectively with special regard to older patients. 46% of all patients were older than 70 years. In contrast to former investigations the rate of myocardial infarction of women over 70 is arised. The reason of admission was reinfarction in 39%. The most frequent risk factors were hypertension and diabetes mellitus; but hypertension is not more frequent than in this age-group of the whole population. A so-called "silent" myocardial infarction occurred in 10-15% of patients over 70 years. The clinical course of acute myocardial infarction was injured by hemodynamic complications in 66%. Ventricular fibrillation was more frequent in younger than in older patients. The reanimation of older patients was successful in 25% primary, but the inhospital mortality was unchanged high (50%). In contrast to younger patients 40% of cases of death occurred after the acute phase in the 2.-4. week of hospital treatment.

Age Factors↗
PubMed1983

Delayed behavioral toxicity of lead with increasing exposure concentration.

Twenty-one-day-old male Long-Evans hooded rats were exposed chronically to drinking solutions containing 500 ppm sodium acetate (controls) or 50, 100, or 500 ppm lead acetate. Performance on a fixed interval 1-min schedule of food reinforcement was assessed over 155 sessions. Blood lead values were monitored serially and brain lead determinations made at the end of testing (335 days of lead exposure). The lowest concentration of lead in the drinking water was associated with increases in the rate of fixed-interval responding over the first 30 sessions. At the two higher concentrations, response rate values similar to controls over the first 40 sessions were followed by rate increases. The latency to maximum rate depended on concentration; the highest concentration was associated with the longest latency. Response rates of rats exposed to 50 ppm lead gradually returned to control levels after 120 sessions, while increased rates were sustained in rats at 100 and 500 ppm lead, even 100 days after lead exposure was terminated. Marked individual differences in susceptibility to lead-induced rate increases were observed in all treatment lead values also reflected exposure concentrations. Blood-brain ratios averaged 0.743 to 0.913, which agree with other data for the rat and human. These results confirm the vulnerability to lead of rats beyond the neonatal period, and extend the range of conditions under which such effects occur.

Animals↗
PubMed1983

Somatosensory thresholds in monkeys exposed to acrylamide.

Six monkeys were trained to report detection of a vibratory or electrical stimulus applied to the fingertip. The vibratory stimuli were presented at two frequencies (40 and 150 Hz). Thresholds were determined with a tracking procedure before, during, and after dosing. Each monkey served as its own control. Four monkeys were dosed orally with 10 mg/kg of acrylamide 5 days a week until the appearance of toxic signs. The total administered dose varied between 320 and 450 mg/kg. The other two monkeys served as time-matched controls. All the monkeys were observed 5 days a week. They were also weighed and presented with a visuomotor task (pickup test) twice a week. Weight loss usually preceded the onset of gross behavioral disturbances, such as loss of balance, tremor, or decreased activity. Impaired coordination, as revealed with the pickup test, paralleled weight loss. Electrical sensitivity was not affected. Vibration sensitivity, however, fell during dosing and remained impaired for several months after dosing ceased, outlasting all the other effects. Recovery of the other indices occurred relatively soon after dosing ended. These data indicate that vibration sensitivity testing can trace the time course of intoxication and recovery in toxic peripheral neuropathies. Furthermore, the differential results obtained with vibratory and electrical stimulation are consonant with a primary effect on end-organ receptors.

Acrylamides↗
PubMed1983

Evolution of virus and defective-interfering RNAs in BHK cells persistently infected with Sindbis virus.

We analyzed a BHK cell line persistently infected with Sindbis virus for 16 months and a virus (Sin-16) cloned from these cells. Sin-16 virus was resistant to the defective interfering particles present in the original infection. We found that (i) cells infected with Sin-16 were impaired in the processing of a viral precursor glycoprotein, (ii) high-multiplicity passaging of Sin-16 gave rise to a variant that was able to generate and be inhibited by defective-interfering particles to which the original Sin-16 virus was resistant, and (iii) the persistently infected culture contained a heterogeneous mixture of defective Sindbis virus RNAs which were not packaged into extracellular particles. To determine whether these intracellular RNAs could interfere with the replication of Sin-16, we analyzed cells that were cloned from the persistently infected culture. One clone (A3) synthesized a single defective viral RNA which was lost with continued passaging in culture. Infection of A3 cells with Sin-16 showed that the presence of the defective RNA greatly enhanced cell survival and led to enrichment of this RNA. In contrast, cured cells were highly susceptible to killing by Sin-16, and survivors did not synthesize this RNA. Thus, A3 cells were not genetically altered in their response to Sin-16, but were protected from the cytopathic effects of infection by an RNA with the characteristics of a defective-interfering RNA.

Animals↗
PubMed1983

Public health consequences of heavy metals in dump sites.

Metals differ from most synthetic organic chemicals in that their clinical manifestations are well known and methods for their measurement in the body are generally well established. Since metals are ubiquitous, special care should be taken to identify the source, whether dump site or not. Isotopic ratios may be used for lead. Time of exposure may be highly variable so estimates will be necessary of integrated "dose-commitment." Transmission to man will follow many pathways. The contamination of children's hands and clothing by dust may be an important route. Because effects are so different, the chemical species (e.g., organic versus inorganic forms) of each metal must be identified. Exposure assessment requires identification of suitable indicator media, usually blood in the case of lead, urine with cadmium and inorganic mercury, and blood or hair with regard to methylmercury. Human head hair may have considerable potential, as it may provide a recapitulation of past exposures. The first health complaints associated with most metals are usually nonspecific. The complex social, political, and legal issues strongly indicate the need for objective tests for health effects. Most important is the identification and measurement of the critical effect, i.e., an effect that alerts the public health authorities that further exposure should cease. For example, in the case of lead, the critical effect is hematologic; with cadmium it is the presence in urine of abnormally high concentration of small molecular weight protein; and with mercury no early objective test has yet been devised.

Adult↗
PubMed1983

The microanalysis of fixed-interval responding.

The fixed-interval schedule of reinforcement is one of the more widely studied schedules in the experimental analysis of behavior and is also a common baseline for behavior pharmacology. Despite many intensive studies, the controlling variables and the pattern of behavior engendered are not well understood. The present study examined the microstructure and superstructure of the behavior engendered by a fixed-interval 5- and a fixed-interval 15-minute schedule of food reinforcement in the pigeon. Analysis of performance typical of fixed-interval responding indicated that the scalloped pattern does not result from smooth acceleration in responding, but, rather, from renewed pausing early in the interval. Individual interresponse-time (IRT) analyses provided no evidence of acceleration. There was a strong indication of alternation in shorter-longer IRTs, but these shorter-longer IRTs did not occur at random, reflecting instead a sequential dependency in successive IRTs. Furthermore, early in the interval there was a high relative frequency of short IRTs. Such a pattern of early pauses and short IRTs does not suggest behavior typical of reinforced responding as exemplified by the pattern found near the end of the interval. Thus, behavior from clearly scalloped performance can be classified into three states: postreinforcement pause, interim behavior, and terminal behavior.

Journal Article↗
PubMed1983

Effect of various compounds on enkephalin hydrolysis by an aminopeptidase from the thermophiles Thermomonospora fusca ATCC 27730 and Thermus thermophilus ATCC 27634.

The microbial peptides amastatin and bestatin as well as several dipeptide analogues of the latter exerted little or no inhibitory effect on enkephalin hydrolysis by an aminopeptidase purified from the thermophiles Thermomonospora fusca, ATCC 27730 (Tf) and Thermus thermophilus, ATCC 27634 (Tt). The enzyme catalyzes the cleavage of the tyrosyl-glycyl bond of leucine- and methionine-enkephalin. Intermediate compounds having the same amino acid sequence as the parent substrate disclosed that the residual tetrapeptide can be further degraded to its constituent parts. Each preparation also hydrolyzes to varying extents neutral dipeptides, tripeptides, tetrapeptides, can be further degraded to its constituent parts. Each preparation also hydrolyzes to varying extents neutral dipeptides, tripeptides, tetrapeptides, and larger molecules containing the Met-enkephalin sequence. The Tf enzyme has a pH optimum of 7.5, Km of 667 microM and Vmax of 92 nmol/min/mg of protein; the Tt enzyme, with a pH optimum of 7.2 has a Km of 400 microM and Vmax of 33 nmol/min/mg of protein. Activated by dithiothreitol (DTT) and inactivated by p-chloro- and p-hydroxymercuribenzoate, both are sulfhydryl enzymes. The activity lost by hydrolysis against EDTA can be restored, wholly or in part, by Co+2, Mg+2, and Mn+2; ions with an inhibitory effect were A1+3, Cd+2, Cu+2, Hg+2, and Zn+2. The enzymes are not glycoproteins since they pass unretained through a Con A-Sepharose column.

Actinomycetales↗