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Biomedical subjects

D A Smith

Publications and source records attributed to D A Smith.

At least 235 records · Page 13Linked to original sources
PubMed1990

New rules for prescribing psychotropics in nursing homes.

Psychopathology is common in elderly nursing home residents, and the use of psychotropics in this setting is likewise common. According to the current literature, however, such use is not always appropriate. In view of this, the Omnibus Budget Reconciliation Act of 1987 establishes new regulations regarding the use of psychotropics in the nursing home setting. Certain drugs will automatically be considered inappropriate. Excessive dosages and extended use will be scrutinized. Periodically checking blood levels of certain drugs and monitoring for tardive dyskinesia will be required. Psychotropic use must be justified by a bonafide diagnosis for which the drug is indicated and not by a symptom alone. Dosage reductions, medication holidays, and the use of nondrug behavioral treatments will be required.

Aged↗
PubMed1989

Electrophysiological and biochemical characterization of the development of alpha 1-adrenergic and 5-HT1 receptors associated with dorsal raphe neurons.

Electrophysiological and quantitative autoradiographic receptor binding approaches were used to characterize the postnatal development of alpha 1-adrenergic and serotonergic receptors in the midbrain dorsal raphe nucleus (DRN) in rats. Dose-response data were obtained from extracellular records of the firing of DRN neurons recorded in midbrain slices perfused with artificial cerebral spinal fluid containing varying concentrations of the drugs investigated. These data indicated that DRN neurons, at all postnatal ages, are equally sensitive to the excitatory effects of phenylephrine (an alpha 1-norepinephrine agonist) and the inhibitory effects of serotonin (5-HT). In contrast, LSD (a 5-HT agonist) was considerably more potent in neonates as compared to adults. With one exception, the autoradiographic binding data was found to be in agreement with the electrophysiological findings. There were no observed changes in the number of alpha 1-adrenergic ([3H]prazosin) binding sites at different ages suggesting that cells in this region exhibit functionally mature alpha 1-adrenergic responses at birth. Similarly, the number of [3H]LSD binding sites was found to increase in older animals consistent with the increased potency of LSD in older animals. Paradoxically, the number of [3H]5-HT sites was observed to increase with age, a finding inconsistent with the functional data obtained using 5-HT in the slice. Hypotheses for the observed discrepancy are examined.

Action Potentials↗
PubMed1989

Molecular transformation of Fusarium solani with an antibiotic resistance marker having no fungal DNA homology.

A vector was constructed for transformation of the plant pathogenic fungus Fusarium solani. The promoter 35Sp, from cauliflower mosaic virus, was fused to the bacterial gene APH(3')II, which confers resistance to the aminoglycoside antibiotic G418. Two transformation procedures were developed: one using isolated fungal protoplasts, the other using germinated fungal spores. A transformation frequency of 3.3 G418-resistant colonies were obtained per microgram DNA. Of 14 colonies analyzed, 12 had vector sequences integrated into their high molecular weight DNA, and 2 were untransformed. Integration was sometimes accompanied by rearrangements of both the vector and flanking fungal DNAs. Primer-extension analysis of the mRNA from one transformant revealed two putative transcription initiation sites in the chimeric APH(3')II gene. Both sites differed from the normal initiation site in plants. This vector will be useful in transformation systems in which integration by non-homologous recombination is desired.

Base Sequence↗
PubMed1989

Metastatic malignant mesothelioma in a dog.

A case of malignant mesothelioma in a 5 1/2-year-old St Bernard dog is described. The distribution of the neoplasm was to the pericardium and peritoneum and not the pleura. Distant metastases were found in the bronchial lymph node and bone marrow.

Animals↗
PubMed1989

Differential effect of long-term oestrogen therapy on trabecular and cortical bone.

The effect of long-term oestrogen therapy has been assessed in 40 oophorectomised women. Twenty-one of the women had received mestranol (mean 26 micrograms/day) and 19 received placebo tablets for a mean duration of 14 yr. A newly developed gamma-ray computed tomography (CT) scanner was used to measure trabecular and cortical bone separately in the distal radius. Bone density in the lumbar spine was measured using dual photon absorptiometry (DPA). Prevention against bone loss was demonstrated at all sites for the mestranol treated group (P less than 0.01). The deficit of radial trabecular bone (27%) was greater than that for radical cortical bone (14%). The deficit for the spine was intermediate (20%). One-year follow-up radial measurements showed a significant 1.2% increase (P less than 0.01) in cortical bone for the treated group. The DPA measurement was found to be best correlated (r = 0.80) with a mixed trabecular and cortical bone parameter in the radius. We conclude that the degree of bone loss at any site is dependent on the proportion of trabecular bone present.

Aged↗
PubMed1989

Regional differences in the binding of selective muscarinic receptor antagonists in rat brain: comparison with minimum-energy conformations.

The binding of selective muscarinic receptor antagonists to regions of rat brain was examined through quantitative autoradiographic techniques. 5,11-Dihydro-11-[(4-methyl-1-piperazinyl)acetyl]-6H- pyrido[2,3-b][1,4]benzodiazepin-6-one [pirenzepine (compound I)] and 11-[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro- 6H-pyrido[2,3-b][1,4]benzodiazepin-6-one [AF-DX 116 (compound II)] were chosen on the basis of their selectivity for M1 and M2 muscarinic receptors, respectively, and similarities in chemical structure. Pirenzepine displayed a higher potency than II for inhibition of [3H]-l-quinuclidinyl benzilate ([3H]-l-QNB) binding to rat brain sections. Scatchard analyses of binding to brain sections revealed heterogeneous binding profiles for both antagonists, suggesting the presence of multiple receptor binding sites. Quantitative autoradiographic techniques were utilized in regional analyses of antagonist binding. Pirenzepine displayed the highest affinity for hippocampal, striatal, and amygdaloid muscarinic receptors (IC50 values less than 0.4 microM), with a slightly lower affinity for cortical receptors (IC50 values between 0.4 and 0.8 microM). Pirenzepine displayed the lowest affinity for thalamic and brainstem regions with IC50 values generally greater than 1.0 microM. In contrast, II bound with higher affinity to muscarinic receptors in brainstem, cerebellar, and hypothalamic nuclei (IC50 values less than 0.5 microM) than to receptors in thalamic nuclei (IC50 values between 0.5 and 2.0 microM). Binding sites with the lowest affinity for II were found in cortical, striatal, and hippocampal regions (IC50 values greater than 2.0 microM). The binding profiles of the two selective muscarinic antagonists reveal the complexity and diversity of muscarinic receptor subtypes throughout the brain. The data provide a basis for identifying muscarinic receptor subtypes (as defined through cloning procedures) with selective ligands. Minimum-energy conformations of pirenzepine and II were calculated by using the program MacroModel (version 2.0). Pirenzepine displayed three energy minima, differing in the relative position of the piperazine ring with respect to the tricyclic system. In contrast, the (diethylamino)methyl substituent on the piperidine ring conferred a much larger set of minimum-energy conformations on II. It is suggested that the greater conformational flexibility of the side chain allows II to achieve a conformation inaccessible to pirenzepine, which allows it to bind preferentially to M2 receptors.

Animals↗
PubMed1989

Managing urinary incontinence in community-residing elderly persons.

This two-year project demonstrated a significant decrease over time in urinary accidents after instruction in Kegel exercises augmented by the use of biofeedback, habit training, and relaxation techniques in 54 cognitively intact volunteers aged 60 years and over who had stress, urge or complex types of incontinence. This decrease in urinary accidents per week was maintained from the end of focused treatment through 6-month and 1-year follow-up, despite the age of the participants, previous urinary-related surgeries, or duration of incontinence.

Aged↗
PubMed1989

Incontinence in elderly homebound patients.

The problem of urinary incontinence in the homebound elderly patient is frequently encountered and is frustrating to the community health nurse. Through a thorough nursing assessment and evaluation, the nurse can successfully employ many simple, effective nursing interventions. Nurses can make a tremendous impact on aiding the homebound incontinent patient by implementing various behavioral interventions.

Aged↗
PubMed1989

Cloning and sequencing of the gerD gene of Bacillus subtilis.

A Tn917 insertion in the same region of the chromosome as gerD gave rise to a mutant (ger-97) with a germination phenotype similar to that of two gerD mutants which germinate abnormally in a range of germinants. The insertion and two gerD mutations were cotransformed with ribosomal protein genes rpoB, rpsE and rpsI. DNA cloned from one side of the insertion carried the 16S end of the ribosomal RNA operon rrnI. These data were consistent with the order rpoB-rpsE-rpsI-gerD/ger-97::Tn917-rrnI. Insertion into the wild-type chromosome of a plasmid carrying DNA adjacent to the insertion permitted the recovery of a 1.8 kb fragment of DNA which complemented ger-97::Tn917 and the gerD mutations. The DNA nucleotide sequence of the region of this fragment at which Tn917 had inserted revealed a 555 bp open reading frame, preceded by a ribosome-binding site and potential sigma E and sigma A promoter regions and encoding a predicted polypeptide of 21,117 Da. This polypeptide was largely hydrophilic but contained a hydrophobic region at the N-terminus resembling a signal peptide.

Amino Acid Sequence↗
PubMed1989

Effect of changing extracellular levels of magnesium on spontaneous activity and glutamate release in the mouse neocortical slice.

1. The mouse neocortical slice preparation, maintained in a two compartment, grease gap bath, exhibits spontaneous depolarizing activity (with or without rhythmic after potentials) after perfusion with magnesium-free artificial cerebrospinal fluid. 2. If the magnesium concentration is decrementally lowered over an extended time period, then incrementally raised following a similar time course, the spontaneous depolarizing shift activity shows a hysteresis (with regard to both frequency and amplitude), the depolarizing shifts being more resistant to magnesium during the incremental period. 3. The amino acid content of the perfusing fluid was analysed by high performance liquid chromatography (h.p.l.c.). Although a basal efflux of 6 amino acids was quantifiable, only glutamate levels increased following superfusion of the preparation with magnesium-free, artificial cerebrospinal fluid. 4. Glutamate release increased to 266% of the resting release in the presence of magnesium within the first 12 min of the change into magnesium-free artificial cerebrospinal fluid. This increase in release preceded the onset of spontaneous depolarising activity. The release of glutamate remained elevated at 182% of control up to 60 min after perfusion with magnesium-free buffer, when depolarizing activity was well established. 5. A model is presented and discussed for the genesis and maintenance of the spontaneous depolarizing shifts. It is suggested that the maintenance of this spontaneous activity reflects a long term enhancement of neocortical neurone excitability which may be related to long term potentiation in the hippocampus.

Amino Acids↗
PubMed1989

Lipophilicity of zwitterionic sulphate conjugates of tiaramide, propranolol and 4'-hydroxypropranolol.

1. Metabolism of basic drugs may result in the formation of zwitterionic sulphate conjugates. The additional ionization introduced by the sulphate group into these compounds compared with the basic parent drug does not produce a corresponding increase in hydrophilic character. 2. Zwitterionic conjugates have constant lipophilicity between their pKa values. The opposite charges on the ionizing functional groups in this pH range appear to cancel the effect of each other on lipophilicity. 3. In the case of propranolol the O-sulphate derivative is more lipophilic than the parent compound at pH values below 7, despite the ionized character of the sulphate function. 4. The decrease in lipophilicity appears to be related to the separation in the molecular structure of the amino and sulphate groups.

Benzothiazoles↗
PubMed1989

Heart rate, activity, duration, and affect in added-purpose versus single-purpose jumping activities.

This research replicates and extends an occupational therapy research project reported by Kircher in 1984. Thirty women aged 18 to 31 years jumped with a rope on one day and jumped in place on another day in a counterbalanced design. Each subject stopped jumping when she reached what she perceived as the very hard level on the Borg Scale of Perceived Exertion (Borg, 1970). Differences from Kircher's design included an imposed target zone formula for safe maximum exertion, use of a portable, more easily read heart rate monitor (Exersentry, Model 3), use of the Osgood Semantic Differential to measure affective meanings, and asking the subjects to identify the type of jumping they preferred. Data analysis supported Kircher's finding that at the given rate of perceived exertion, heart rate increase after jumping rope was significantly higher (p = .01) than after jumping without a rope. The difference in duration of jumping approached significance (p = .06), but in the direction opposite to what Kircher found. There were no significant differences in affective meanings or preference. Results are discussed in terms of the need for a growing body of occupational therapy literature in regard to the purposefulness of activities.

Adolescent↗
PubMed1989

Added-purpose versus rote exercise in female nursing home residents.

Seven recent experimental and quasi-experimental studies have compared the exercise of subjects instructed to pursue some added goal (often termed purposeful activity) with the exercise of subjects instructed to exercise without the suggestion of an added goal (often termed nonpurposeful activity). This article suggests a new terminology for this type of independent variable and describes an experiment within this developing tradition. An occupational form designed, through materials and instructions, to elicit a rotary arm exercise with the added purpose of stirring cookie dough was compared with an occupational form designed to elicit the rotary arm exercise with no added purpose. The subjects were 30 elderly female nursing home residents randomly assigned to the occupational forms. Results indicated that the added-purpose, occupationally embedded exercise condition elicited significantly more exercise repetitions than did the rote exercise condition (one-tailed p = .012). Exercise duration and exercise stoppages were also recorded. This study provides additional support for the traditional occupational therapy idea of embedding exercise within occupation. Suggestions are made for future research involving the experimental analysis of therapeutic occupation.

Aged↗
PubMed1989

New-generation portable tonometers: comparison of the Keta and Goldmann tonometers.

The Keta Smart-001 is a recently introduced portable battery-operated tonometer with a digital readout. To determine the reliability of the Keta tonometer, intraocular pressure (IOP) measurements were taken in a masked fashion with the Keta tonometer and the Goldmann tonometer in both eyes of 60 patients (20 with and 40 without glaucoma) recruited from general ophthalmology and glaucoma clinics. The results were analysed with an F-test analysis of variance. The Keta tonometer significantly underread the IOP and was totally unreliable in patients with glaucoma. Our results indicate that Keta tonometry should not be used for the screening and management of glaucoma.

Adult↗
PubMed1989

Management of the second stage of labor: a review (Part I).

The second stage of labor is defined as that time from the completion of dilitation of the cervix to the delivery of the infant. Considerable controversy exists in the current obstetric and midwifery literature concerning the appropriate management of this stage of labor. With increased use of regional anesthesia, electronic fetal monitoring and the shift in favor of active management of labor, the second stage is often accompanied by forceful bearing-down efforts, repeated Valsalva maneuvers and an increase in the use of forceps, vacuum extraction and episiotomies. Probably the single strongest point resulting in active intervention in the second stage of labor is the rigid use of the Friedman Curve. This approach tends to insist upon a predetermined time interval and promotes early intervention. The opinions on both sides of this controversy are the topic of this review.

Female↗