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Biomedical subjects

D Tucker

Publications and source records attributed to D Tucker.

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

Outcome of abuse during childhood among pregnant low income women.

The outcome of experiencing abuse as a child was studied by comparing pregnant women who did recall versus those who did not recall this type of maltreatment. Fourteen hundred low income women were interviewed in prenatal clinic; those who said they were both punished by abuse and beaten by caretakers as children were considered abused. Abuse was recalled by more white than black women but families were followed after delivery and protective service reports of abuse for their offspring were equal. Because of low numbers, black subjects were dropped and the 95 white women who recalled abuse during childhood were compared to the remaining 832 white subjects. The groups did not differ in attitude about current pregnancy, age or marital status, and no differences were found for their children at birth. Abused mothers were more likely to have felt unwanted and unloved as children and to have lower self-images and more isolation than controls. Abused mothers had greater stress, and many of their stresses reflected disturbances in interpersonal relationships. Thus, women abused as children had some characteristics similar to those of known child abusers. Although abused women had more aggressive tendencies, their children were reported to protective services for abuse at the same frequency as control children. Intergenerational transmission of abuse was therefore not demonstrated prospectively. Classic theories of child abuse suggest a special child, special parent and stress act as independent agents to cause abuse. The above data suggest, alternatively, that abuse during childhood may lead to other risk characteristics and to greater stress. These may act together to increase risk for abuse. The special child may have an independent influence on abuse.

Adaptation, Psychological↗
PubMed1985

Responsiveness of the olfactory receptor cells in dog to some odors.

A preparation has been developed in the dog which allows recording the electrical activity from an olfactory nerve twig containing the axons of a small group of olfactory receptor cells. The dog's response to n-pentyl acetate is vigorous and stable, like that of other air-breathing animals. The dog's response magnitude dependence on the nasal flow rate was noticeable for n-pentyl acetates, but not so great as for n-butyric acid. The response to n-butyric acid strongly depends on the nasal flow. The start of the nasal air flow caused an increase of neural activity, which is called flow response. The results show that the nasal flow rate is a very important factor which determines the response to odors. Methyl p-hydroxybenzoate is known as a dog's pheromone, however, this odor caused the feeble response in the electrical activity of the dog's olfactory receptor cells. The differences may be dependent on several factors.

Animals↗
PubMed1984

Hypopyon following laser iridotomy.

Two patients who had laser iridotomy performed for pupillary block glaucoma developed hypopyon following surgery. One case had iris bombé with rubeosis iridis, and the other had chronic angle closure glaucoma. Factors contributing to inflammation and possible hypopyon following laser iridotomy are discussed.

Adult↗
PubMed1983

Lack of Z-DNA conformation in mitomycin-modified polynucleotides having inverted circular dichroism.

Poly(dG-dC) . poly(dG-dC) and Micrococcus lysodeikticus DNA were modified by exposure to reductively activated mitomycin C, an antitumor antibiotic. The resulting covalent drug-polynucleotide complexes displayed varying degrees of CD inversions, which are strikingly similar to the inverted spectrum observed with Z-DNA. The following criteria have been used to establish, however, that the inverted CD pattern seen in mitomycin C-polynucleotide complexes does not reflect a Z-DNA conformation. (i) The ethanol-induced transition of poly(dG-dC) . poly(dG-dC) from B to Z conformation is not facilitated but rather is inhibited by mitomycin C modification. This may be due to the presence of crosslinks, (ii) Radioimmunoassay indicated no competition for Z-DNA-specific antibody by any of the mitomycin C-modified polynucleotides, (iii) 31P NMR of the complexes yielded a single relatively narrow resonance, which is inconsistent with the dinucleotide repeat characteristic of Z-DNA. Alternative explanations for the inverted CD pattern include a drug-induced left-handed but non-Z conformational change or the superposition of an induced CD onto the CD of B-DNA due to drug-base electronic interactions. These results illustrate the need for caution in interpreting CD changes alone as an indication of Z-DNA conformation.

Circular Dichroism↗
PubMed1981

Does intermittent mandatory ventilation accelerate weaning?

Intermittent mandatory ventilation (IMV) was introduced to facilitate the weaning of patients from mechanical ventilation. The outcome of ventilator management in 116 patients who were treated in the first three months of 1975 was compared retrospectively with that of 135 patients who were treated in the first three months of 1976. All patients who were treated in 1975 received conventional (assisted or controlled) mechanical ventilation. In 1976, seventy-seven patients (57%) were treated with the use of IMV, and 58 (43%) were treated with the use of conventional mechanical ventilation. Sixty-five patients who were treated in 1976 with the use of IMV were matched with patients who were treated in 1975 with the use of conventional ventilation, on the basis of age, sex, race, history of pulmonary disease, smoking history, diagnosis, service, and location of therapy. The average time spent on a ventilator by the IMV patients was 145 hours, whereas the matched control patients spent 142 hours. The length of hospitalization was 36 days for the IMV patients and 30 days for the control patients. These time periods were not significantly different and indicate that IMV did not reduce the length of ventilator management.

Acute Disease↗
PubMed1981

A practical approach to management of lithium concurrent with hyponatremia, diuretic therapy and/or chronic renal failure.

Lithium therapy concurrent with hyponatremia, thiazides and possibly other diuretics and/or chronic renal failure has generally been avoided. However, despite greater risk for lithium toxicity, such combinations are feasible with appropriate precautions, especially lower lithium dosage and closer follow-up. Under the right circumstances hyponatremia, diuretics, and/or chronic renal failure are only relative lithium contraindications.

Bipolar Disorder↗
PubMed1978

Biochemical investigations in cultured skin fibroblasts from patients with Duchenne muscular dystrophy.

Cultured skin fibroblasts from patients with Duchenne muscular dystrophy were studied with a double-labeling procedure. Preliminary evaluation of the growth characteristics and average viability of dystrophic cells did not show any major abnormalities. Analysis of doubly labeled fibroblast mixture did not disclose any consistent anomaly in the distribution of subcellular fractions or in the major protein components of dystrophic fibroblasts.

Cell Count↗
PubMed1977

Specific anosmia in the laboratory mouse.

As an approach to a general theory of olfaction, different specific anosmia phenotypes characterized by different profiles of odorant sensitivities have been proposed for humans. In the present experiments, male inbred mice were tested for relative odorant sensitivity using a conditioned aversion technique and odors classified as primary or complex for humans. C57BL/6J and C57BL/10J mice appeared to be less sensitive to the primary odorant isovaleric acid than were males of seven other inbred strains (A/J, AKR/J, BALB/cJ,C3HeB/FeJ, DBA/2J, SJL/J, and SWR/J). In comparisons of C57BL/6J and AKR/J strains, the relative insensitivity of C57 to isovaleric acid did not generalize to the musklike primary odor of pentadecalactone or to the complex odor of amyl acetate. The C57BL/6J genotype may provide an animal model of a specific anosmia as characterized among humans.

Animals↗
PubMed1976

The underwater electro-olfactogram: a tool for the study of the sense of smell of marine fishes.

Recording the olfactory receptor activity of marine fishes presents problems due to the shunting of the electrical signals by the highly conductive sea water, which results in significant signal loss. By recording the large signal-to-noise ratio D. C. potentials using the underwater electro-olfactogram (EOG), we were able to study olfactory receptor properties of freshwater and marine fishes in a comparable manner.

Action Potentials↗
PubMed1975

Recovery of structure and function following transection of the primary olfactory nerves in pigeons.

Preliminary experimentation on ring doves to ascertain whether they might regulate any aspects of their reproductive behavior in terms of olfactory cues was vitiated by the discovery that their sectioned olfactory nerves had apparently regenerated. Concurrent work on frogs has shown that the olfactory receptors degenerate after axotomy and are replaced by new ones. This phenomenon was studied in pigeons. All transected nerves were found to be healed. Electrical recording from the regenerated nerves revealed apparently normal receptor function and, indirectly, autonomic reflex responsiveness. Previously untrained pigeons learned an olfactory discrimination after reconstitution of the peripheral olfactory system using a conditioned suppression procedure. The olfactory nerves of trained pigeons were sectioned and the behavioral response recovered within 16-82 days. The gross sizes of primary olfactory nerves and olfactory bulbs were frequently much less than those of controls, but on the ultrastructural level there was no recognizable morphological deficiency in the receptor cellular organelles or terminal synaptic contacts in bulbar glomeruli. Recent results by other workers indicate that pigeons utilize olfactory cues in homing performance.

Action Potentials↗