PubMed Health⌕ Search

Biomedical subjects

K Baldwin

Publications and source records attributed to K Baldwin.

At least 19 recordsLinked to original sources
PubMed2006

Comparative genomics of the lactic acid bacteria.

Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

Animals↗
PubMed2003

Under-reporting of erectile dysfunction among men with unrelated urologic conditions.

To evaluate the incidence of erectile dysfunction (ED) in men with unrelated urologic conditions paying special attention to the reasons for patient under-reporting. We asked 500 consecutive men over age 50 visiting their urologist's office for problems unrelated to ED, whether or not they had any difficulty with their potency. Those who gave a positive response were then asked to complete a questionnaire to assess their reasons for under-reporting and whether they had had any previous discussions with their primary-care physicians regarding their sexual function. Out of 500 men, 218 (44%) reported experiencing some degree of ED. Reasons for failure to discuss ED with their urologist included: 161 out of 218 (74%) were embarrassed; 27 out of 218 (12%) felt that ED was a natural part of aging; 20 out of 218 (9%) were unaware that urologists dealt with the problem of ED; and 10 out of 218 (5%) did not consider the problem worthy of attention. Only 48 of the 218 men with ED reported having previous discussions about their problem with their primary-care physicians. Of the 170 patients who did not report having such discussions, 140 (82%) reported that they would have liked their primary-care physician to have initiated a discussion of ED during their routine visits. In conclusion. a significant percentage of older men with some unrelated urologic complaint also suffer from some degree of ED and remain undiagnosed unless specifically questioned about this problem. By far, the most common reason for under-reporting of ED was patient embarrassment. While urologists are able to elicit information regarding erectile function on specific questioning, patients appear comfortable and willing to discuss their potency with primary-care physicians.

Aged↗
PubMed2003

Apertureless near-field Raman spectroscopy.

We report on the tip-enhanced Raman spectra of C60 obtained on a custom-built apertureless scanning near-field optical microscope. A commercial atomic force microscope tip coated with 100 nm thickness of gold was used to enhance locally the Raman signal and permit topographic and spectral information to be acquired simultaneously. We present preliminary data which demonstrate the tip enhancement effect using C60 as a test sample.

Journal Article↗
PubMed2001

Paper-like electronic displays: large-area rubber-stamped plastic sheets of electronics and microencapsulated electrophoretic inks.

Electronic systems that use rugged lightweight plastics potentially offer attractive characteristics (low-cost processing, mechanical flexibility, large area coverage, etc.) that are not easily achieved with established silicon technologies. This paper summarizes work that demonstrates many of these characteristics in a realistic system: organic active matrix backplane circuits (256 transistors) for large ( approximately 5 x 5-inch) mechanically flexible sheets of electronic paper, an emerging type of display. The success of this effort relies on new or improved processing techniques and materials for plastic electronics, including methods for (i) rubber stamping (microcontact printing) high-resolution ( approximately 1 microm) circuits with low levels of defects and good registration over large areas, (ii) achieving low leakage with thin dielectrics deposited onto surfaces with relief, (iii) constructing high-performance organic transistors with bottom contact geometries, (iv) encapsulating these transistors, (v) depositing, in a repeatable way, organic semiconductors with uniform electrical characteristics over large areas, and (vi) low-temperature ( approximately 100 degrees C) annealing to increase the on/off ratios of the transistors and to improve the uniformity of their characteristics. The sophistication and flexibility of the patterning procedures, high level of integration on plastic substrates, large area coverage, and good performance of the transistors are all important features of this work. We successfully integrate these circuits with microencapsulated electrophoretic "inks" to form sheets of electronic paper.

Journal Article↗
PubMed2001

When your patient can no longer live independently: a guide to supporting the patient and family.

This article uses a case study format to illustrate the Expanded Family Life Cycle Theory of Carter and McGoldrick (1999). This theory provides nurses and other health care providers with tools for assessing and planning care for older adults facing stressful life transitions. The individual and family are assessed as a unit embedded within their community. This multicontextual framework is applied to an elderly woman's transition from independent living to supervised living in a facility and illustrates the ease of use for practicing nurses. Suggestions are also offered to assist health care providers in supporting older adults and their families in making this significant transition.

Adaptation, Psychological↗
PubMed2000

Risk-resistance adaptation model for caregivers and their children with sickle cell syndromes.

This investigation examined the risk-resistance adaptation model for children with sickle cell disease and their primary caregivers. Participants were 55 children, ranging in age from 5 to 16 years with a mean age of 9 years 2 months, diagnosed with sickle cell disease and their primary caregivers, recruited from a university medical center. Measures included adjustment (i.e. primary caregiver and child adjustment), risk factors (i.e. disease and disability, functional independence, and psychosocial stressors), resistance factors (i.e. intrapersonal health locus of control, social-ecological), and stress processing (coping). Primary caregivers' adjustment was associated with developmental coping, changeR2 = .08, and child adaptation was associated with an internal health locus of control, changeR2 = .22. An indirect effect of primary caregivers' coping on child adjustment was found through influence on primary caregivers' adjustment, changeR2 = .11. The findings support research among other chronically ill populations that suggests an association between coping and disease adjustment. The results were interpreted to support the use of theoretically driven models in predicting the adaptation of children with chronic illness and adjustment in their caregivers.

Adaptation, Psychological↗
PubMed2000

Effects of training on attention to acoustic cues.

Learning new phonetic categories in a second language may be thought of in terms of learning to focus one's attention on those parts of the acoustic-phonetic structure of speech that are phonologically relevant in any given context. As yet, however, no study has demonstrated directly that training can shift listeners' attention between acoustic cues given feedback about the linguistic phonetic category alone. In this paper we discuss the results of a training study in which subjects learned to shift their attention from one acoustic cue to another using only category-level identification as feedback. Results demonstrate that training redirects listeners' attention to acoustic cues and that this shift of attention generalizes to novel (untrained) phonetic contexts.

Adolescent↗
PubMed1998

Time-dependent stimulation by aldosterone of blocker-sensitive ENaCs in A6 epithelia.

To study and define the early time-dependent response (< or = 6 h) of blocker-sensitive epithelial Na+ channels (ENaCs) to stimulation of Na+ transport by aldosterone, we used a new modified method of blocker-induced noise analysis to determine the changes of single-channel current (iNa) channel open probability (Po), and channel density (NT) under transient conditions of transport as measured by macroscopic short-circuit currents (Isc). In three groups of experiments in which spontaneous baseline rates of transport averaged 1.06, 5.40, and 15.14 microA/cm2, stimulation of transport occurred due to increase of blocker-sensitive channels. NT varied linearly over a 70-fold range of transport (0.5-35 microA/cm2). Relatively small and slow time-dependent but aldosterone-independent decreases of Po occurred during control (10-20% over 2 h) and aldosterone experimental periods (10-30% over 6 h). When the Po of control and aldosterone-treated tissues was examined over the 70-fold extended range of Na+ transport, Po was observed to vary inversely with Isc, falling from approximately 0.5 to approximately 0.15 at the highest rates of Na+ transport or approximately 25% per 3-fold increase of transport. Because decreases of Po from any source cannot explain stimulation of transport by aldosterone, it is concluded that the early time-dependent stimulation of Na+ transport in A6 epithelia is due exclusively to increase of apical membrane NT.

Aldosterone↗
PubMed1997

Interaction of thyroid state and denervation on skeletal myosin heavy chain expression.

The goal of this study was to examine the effects of altered thyroid state and denervation (Den) on skeletal myosin heavy chain (MHC) expression in the plantaris and soleus muscles. Rats were subjected to unilateral denervation (Den) and randomly assigned to one of three groups: (1) euthyroid; (2) hyperthyroid; (3) and hypothyroid. Denervation caused severe muscle atrophy and muscle-type specific MHC transformation. Denervation transformed the soleus to a faster muscle, and its effects required the presence of circulating thyroid hormone. In contrast, denervation transformed the plantaris to a slower muscle independently of thyroid state. Furthermore, thyroid hormone effects did not depend upon innervation status in the soleus, while they required the presence of the nerve in the plantaris. Collectively, these findings suggest that both thyroid hormone and intact nerve (a) differentially affect MHC transformations in fast and slow muscle; and (b) are important factors in regulating the optimal expression of both type I and IIB MHC genes. This research suggests that for patients with nerve damage and/or paralysis, both muscle mass and biochemical properties can also be affected by the thyroid state.

Animals↗
PubMed1997

Steroid hormone-dependent expression of blocker-sensitive ENaCs in apical membranes of A6 epithelia.

Weak channel blocker-induced noise analysis was used to determine the way in which the steroids aldosterone and corticosterone stimulated apical membrane Na+ entry into the cells of tissue-cultured A6 epithelia. Among groups of tissues grown on a variety of substrates, in a variety of growth media, and with cells at passages 73-112, the steroids stimulated both amiloride-sensitive and amiloride-insensitive Na+ transport as measured by short-circuit currents in chambers perfused with either growth medium or a Ringer solution. From baseline rates of blocker-sensitive short-circuit current between 2 and 7 microA/cm2, transport was stimulated about threefold in all groups of experiments. Single channel currents averaged near 0.3 pA (growth medium) and 0.5 pA (Ringer) and were decreased 6-20% from controls by steroid due to the expected decreases of fractional transcellular resistance. Irrespective of baseline transport rates, the steroids in all groups of tissues stimulated transport by increase of the density of blocker-sensitive epithelial Na+ channels (ENaCs). Channel open probability was the same in control and stimulated tissues, averaging approximately 0.3 in all groups of tissues. Accordingly, steroid-mediated increases of open channel density responsible for stimulation of Na+ transport are due to increases of the apical membrane pool of functional channels and not their open probability.

Aldosterone↗
PubMed1996

Presentation format in analogue studies: effects on participants' evaluation.

Whether presentation format (video, audio, written transcript, or written transcript with photograph) affects participants' responses to counseling scenarios in an analogue study was examined. After watching a brief counseling session presented in one of four formats, 131 participants completed three instruments measuring counselor credibility and expectations. Results revealed significant differences among the formats on teh COunselor Rating Form (CRF-S; Corrigan & Schmidt, 1983) Trustworthiness and Expertness Scales, with transcripts with pictures rated the highest (higher than videotape and audiotape) and transcripts without pictures rated second highest (higher than video). No significant differences between the presentation formats were revealed on the Expectations about Counseling Questionnaire (EAC; Tinsley, Workman, & Kass, 1980) or 15 Personal Problem Inventory (15PPI; Cash, Begley, McCown, & Weise, 1975). Results suggest that studies using differing formats with the CRF-S are not necessarily comparable and that the four types of analogue approaches may not be interchangeable.

Adult↗
PubMed1996

Rehabilitation after total knee arthroplasty: a comparison of 2 rehabilitation techniques.

This study was conducted to compare postoperative total knee arthroplasty rehabilitation protocols. The hypothesis of this study was that patients undergoing total knee arthroplasty could achieve range of motion and hospital discharge in the same period using a postoperative rehabilitation protocol that did not use a continuous passive motion machine. This randomized prospective study compared 46 total knee arthroplasties in which a continuous passive motion machine was used with 37 total knees that were rehabilitated with early passive flexion of the knee (named drop and dangle protocol). Postoperative physical therapy regimens were otherwise the same for both groups. Surgical technique was the same for both groups except for closure which was performed in the drop and dangle group with the knee at 90 degrees to 95 degrees flexion. Only patients with osteoarthritis were included in the study, and in both groups of patients received the same prosthetic components. Patients in the drop and dangle group were discharged from the hospital 1 day earlier (p = 0.01) and had a statistically better extension range of 2.8 degrees at 6 months (p = 0.03). Knees in the drop and dangle group had less drainage (p = 0.06). Range of motion and hospital discharge can be achieved in a similar time interval with the drop and dangle technique as with using a continuous passive motion device, and that such a device is not required for postoperative knee rehabilitation.

Adult↗
PubMed1996

Na+/H+ antiport activity conferred by Bacillus subtilis tetA(L), a 5' truncation product of tetA(L), and related plasmid genes upon Escherichia coli.

An Escherichia coli transformant expressing the Bacillus subtilis tetA(L) gene from a weak promoter was challenged by growth on medium with low, increasing tetracycline concentrations. Changes in the substrate preference ratios of the TetA(L)-mediated resistances and antiports were examined in view of recent findings suggesting that TetA(L) catalyzes efflux of Na+ in exchange for protons in addition to having the ability to catalyze metal-tetracycline/H+ antiport. After growth of the transformant on 1 microgram or more of tetracycline per ml for 12 to 15 h, the tetA(L) gene in the plasmid was found to be disrupted by an IS10 element 50 bp from the 5' end of the coding sequence. This disrupted recombinant plasmid, pKB1, conferred greater tetracycline resistance and higher levels of membrane metal-tetracycline/proton antiport than the original plasmid, pJTA1, but conferred lower NA+ resistance and Na+/H+ antiport levels than the original plasmid. The results indicate that the 5' end of the gene is necessary for optimal Na+/H+ antiport but that some such activity as well as robust tetracycline/H+ antiport persists in its absence. Two plasmid genes, tet(K) and qacA, were compared with tetA(L) vis-à-vis their abilities to enhance the Na+/H+ antiporter activity of everted vesicles from E. coli transformants. tet(K), which is more closely related to tetA(L), catalyzed 22Na+ uptake by energized vesicles, whereas the less closely related qacA gene did not.

Bacillus subtilis↗
PubMed1995

In vivo and in vitro pressor effects of erythropoietin in rats.

Hypertension (HTN) is a common complication of recombinant erythropoietin (EPO) therapy, but the mechanism of the EPO-associated HTN is uncertain. In the present study we examined the effects of EPO and the vehicle alone on rat caudal artery contractile response and basal and thrombin-stimulated platelet cytosolic Ca2+ concentration ([Ca2+]i) in vitro and on blood pressure (BP) and heart rate in vivo. At high concentrations (200 U/ml) EPO caused a small but consistent contraction in the caudal artery rings (P < 0.01) without affecting the response to either angiotensin II (ANG II) or the alpha 1-agonist methoxamine. Incubation with EPO significantly increased basal platelet [Ca2+]i (P < 0.01) and augmented the thrombin-induced rise of [Ca2+]i in Ca(2+)-free medium (P < 0.05). Long-term EPO administration led to a significant elevation of BP within 2 wk regardless of whether the hematocrit was allowed to rise or was kept constant by dietary iron deficiency. In contrast, single intravenous administration of high-dose EPO (400 and 5,000 U/kg), estimated to yield plasma concentrations comparable with those employed in vitro, failed to either alter BP or modify the BP response to ANG II during a 60-min observation period. This was associated with a significant rise in plasma guanosine 3',5'-cyclic monophosphate but no discernible change in plasma atrial natriuretic peptide, suggesting enhanced nitric oxide (NO) release. Thus, at high concentrations, EPO appears to possess a fast-acting pressor effect in vitro but not in vivo. The observed discrepancy may be due to enhanced NO release with EPO administration in vivo. However, HTN does occur with repeated EPO administration in a time-dependent and hematocrit-independent manner. This suggest that expression of the hypertensive effect of EPO in vivo involves a gradual conditioning process.

Animals↗
PubMed1993

Psychosocial and family functioning in children with sickle cell syndrome and their mothers.

OBJECTIVE: The purpose of this study was to compare the psychiatric functioning of 61 sickle cell youth and their families with nondiseased sibling controls. METHOD: Functioning assessed by multiple informants included indices of behavioral, cognitive, and family/interpersonal functioning, self-esteem, life events, coping strategies, temperament, adaptive behavior, and parental psychopathology. RESULTS: Key findings were that sickle cell patients evidenced more depressive symptoms and associated attributional style, and externalizing behavioral difficulties than did nondiseased siblings. With age, sickle cell youth evidence increasing adaptive behavior deficits and internalizing symptoms. Illness severity was related to symptoms of internalizing behavior and fewer daily living skills. Associations were found between maternal and child coping. CONCLUSIONS: It is recommended that psychiatric consultations routinely be conducted with these children, particularly at times of family stress and developmental transitions. Psychiatric interventions should focus on ameliorating emotional difficulties via enhancing adaptive coping strategies.

Adaptation, Psychological↗