Biomedical subjects
R Winters
Publications and source records attributed to R Winters.
Increases in manic symptoms after life events involving goal attainment.
Bipolar disorder has been conceptualized as an outcome of dysregulation in the behavioral activation system (BAS), a brain system that regulates goal-directed activity. On the basis of the BAS model, the authors hypothesized that life events involving goal attainment would promote manic symptoms in bipolar individuals. The authors followed 43 bipolar I individuals monthly with standardized symptom severity assessments (the Modified Hamilton Rating Scale for Depression and the Bech-Rafaelsen Mania Rating Scale). Life events were assessed using the Goal Attainment and Positivity scales of the Life Events and Difficulties Schedule. As hypothesized, manic symptoms increased in the 2 months following goal-attainment events, but depressed symptoms were not changed following goal-attainment events. These results are congruent with a series of recent polarity-specific findings.
Transesophageal echocardiographic visualization of left ventricular malpositioned pacemaker electrodes: implications for lead extraction procedures.
Two cases of malpositioned LV electrodes are presented. Transesophageal echocardiography (TEE) allowed for a careful inspection of left-sided leads and for tracking their course. One LV and two right-sided leads were safely retrieved with TEE monitoring. One chronic LV lead was left in place as it was heavily fibrosed. TEE was helpful in the inspection and monitoring of the extraction and also in guided traction efforts. This is the first published report of echocardiographic visualization of the lead retrieval procedure.
Mineralogical features associated with cytotoxic and proliferative effects of fibrous talc and asbestos on rodent tracheal epithelial and pleural mesothelial cells.
Inhalation of asbestos fibers causes cell damage and increases in cell proliferation in various cell types of the lung and pleura in vivo. By using a colony-forming efficiency (CFE) assay, the cytotoxicity and proliferative potential of three mineral samples containing various proportions of fibrous talc were compared to NIEHS samples of crocidolite and chrysotile asbestos in cell types giving rise to tracheobronchial carcinomas, i.e., hamster tracheal epithelial (HTE) cells, and mesotheliomas, i.e., rat pleural mesothelial (RPM) cells. Characterization of mineralogical composition, surface area, and size distributions as well as proportions of fibers in all mineral samples allowed examination of data by various dose parameters including equal weight concentrations, numbers of fibers >5 micron in length, and equivalent surface areas. Exposure to samples of asbestos caused increased numbers of colonies of HTE cells, an indication of proliferative potential, but fibrous talc did not. RPMs did not exhibit increased CFE in response to either asbestos or talc samples. Decreased numbers of colonies, an indication of cytotoxicity, were observed in both cell types and were more striking at lower weight concentrations of asbestos in comparison to talc samples. However, all samples of fibrous minerals produced comparable dose-response effects when dose was measured as numbers of fibers greater than 5 micron or surface area. The unique proliferative response of HTE cells to asbestos could not be explained by differences in fiber dimensions or surface areas, indicating an important role of mineralogical composition rather than size of fibers.
Cardiorespiratory components of defense reaction elicited from paraventricular nucleus.
The present study was conducted to test the hypothesis that the paraventricular nucleus of the hypothalamus (PVN) is involved in the mediation or modulation of the cardiorespiratory components of the defense reaction (DR) in rabbits. Electrical stimulation of the PVN elicited increases in blood pressure and heart rate, hyperventilation, decreased blood flow to the visceral organs, and an increase in blood flow to the hindlimbs that was mediated by an atropine-sensitive vasodilation system. This response pattern is nearly identical to the one that is elicited by electrical stimulation of the hypothalamic defense area. In addition, the cardiomotor component of the baroreceptor reflex was observed to be suppressed during electrical stimulation of the PVN. Previous studies have shown that electrical stimulation of the hypothalamic defense area also leads to inhibition of the cardiomotor component of the baroreceptor reflex. The results of the present study provide evidence that the PVN is involved in the mediation or modulation of the defense reaction.
Functional relationship between the hypothalamic vigilance area and PAG vigilance area.
The vigilance reaction is characterized by a large bradycardia, a pressor response, and inspiratory apnea in anesthetized rabbits and the inhibition of movement in conscious rabbits. This affective response pattern can be elicited by electrical stimulation of the dorsolateral hypothalamus (the hypothalamic vigilance area) or the ventrolateral periaqueductal gray (the periaqueductal gray vigilance area). The present study sought to advance our understanding of the functional relationship between the hypothalamic vigilance area (HVA) and the periaqueductal gray vigilance area (PVA) by measuring the effects of transverse transections of the caudal portion of the ventrolateral PAG (vlPAG) upon the cardiovascular responses elicited from the dorsolateral hypothalamus and the rostral vlPAG. Selective transverse transections of the caudal vlPAG significantly reduced the magnitudes of the bradycardia and pressor response elicited by stimulation of the PVA rostral to the transection site, but had minimal impact on the cardiovascular responses evoked by stimulation of the HVA. These findings suggest that the cardiovascular responses elicited by stimulation of the vlPAG are mediated by a neural pathway that is parallel, at least in part, to the one that subserves the response elicited from the HVA. The results also provide support for the view that the PAG is not an essential structure in the mediation of the autonomic components of affective behaviors involving behavioral inhibition.
Clinical assessment of adrenergic tone and responsiveness to beta-blocker therapy in patients with symptomatic ventricular tachycardia and no apparent structural heart disease.
To further define the relation between changing adrenergic tone, beta-blocker therapy, and clinical ventricular tachycardia (VT), we evaluated these factors in 35 patients with VT unrelated to coronary artery disease or ventricular dysfunction. Testing included Holter monitoring (91% had VT), exercise test (69% had VT), Adrenergic responsiveness of VT was graded according to diurnal variation, response to exercise, isoproterenol infusion, and response to beta-blockers. beta-Blockers were effective and well tolerated in this population. There was also a predictable relation between changing adrenergic tone and the arrhythmia response to beta-blocker therapy.
Behavioral characteristics of defense and vigilance reactions elicited by electrical stimulation of the hypothalamus in rabbits.
An automated tracking system was used to assess the behavioral changes elicited by electrical stimulation of the hypothalamic sites that yield the cardiorespiratory components of defense reaction and vigilance reaction in rabbits. Electrical stimulation of the hypothalamic defense area (HDA) at intensities near threshold led to cessation of body movements coupled with head movements suggesting increased attention to the environment. HDA stimulation at higher intensities evoked agitated running and hindlimb thumping; the amount of running was proportional to stimulus intensity. Electrical stimulation of the hypothalamic vigilance area (HVA) at intensities near threshold elicited orienting behaviors that were similar to those elicited by stimulating the HDA at low suprathreshold current intensities. Stimulation of the hypothalamic vigilance area (HVA) at higher intensities elicited phasic immobility, increased extensor muscle tension, and head tremor. The behavioral changes elicited by HDA and HVA stimulation were accompanied by pupil dilation and exophthalmos.
Modulation of neuronal firing in the medullary solitary complex by electrical stimulation of the hypothalamic defense and vigilance areas in rabbits.
The present study sought to establish functional connections between two regions in the hypothalamus associated with the cardiorespiratory concomitants of affective behavior, and neurons in the dorsal medulla thought to be involved in the mediation of the baroreceptor reflex. Single cell recordings were made in the solitary complex of the medulla (nucleus of the tractus solitarius and dorsal vagus nucleus) of anesthetized rabbits. An attempt was made to modulate the activity of these neurons by electrically stimulating two hypothalamic sites: the hypothalamic defense area (HDA) and the hypothalamic vigilance area (HVA). Responses of solitary complex neurons to a bolus injection of phenylephrine and an injection of physiological saline in a blind sac preparation were assessed in order to test for baroreceptor input. Electrical stimulation of the HDA or the HVA was found to decrease the firing rate of most solitary complex neurons that responded to hypothalamic stimulation. The cells that did show an increase in firing rate were responding to HVA stimulation. Ninety-two percent of the neurons in the solitary complex that responded to HDA or HVA stimulation were also affected by baroreceptor activation. The connections between the HDA, HVA and the solitary complex may account, in part, for the distinctive patterns of cardiorespiratory responses observed when stimulating these two hypothalamic regions.
Glutamine protects Chinese hamster ovary cells from radiation killing.
Chinese Hamster Ovary (CHO) cells were propagated in vitro and exposed to varying doses of ionizing radiation. The surviving fraction of cells was determined, being found to be a function of the radiation dose. The cell survival curves obtained as a function of radiation dose were modified by the inclusion of varying doses of glutamine in the medium with glutamine demonstrating a radioprotective effect. The radioprotectant effect of glutamine for CHO cells was more pronounced at higher radiation doses. Glutamine has been categorized as a non-essential amino acid in that it can be synthesized in some tissues; however, a number of cell lines require glutamine to survive and grow in vitro and supplementation of glutamine has been found to ameliorate the stress of surgery or irradiation to the gastrointestinal tract. It may be appropriate to consider glutamine as a conditionally essential amino acid.
Neuroleptic malignant syndrome: a case for electroconvulsive therapy.
A case of prolonged and refractory neuroleptic malignant syndrome was treated successfully with electroconvulsive therapy. Neuroleptic malignant syndrome and its treatment are reviewed.
The use of the osteocutaneous groin flap in gunshot wounds of the hand.
Since 1972, the groin flap has been used as an excellent source of skin coverage for the hand. This flap can incorporate the underlying iliac crest to provide both soft tissue and vascularized bone for the reconstruction of complex hand injuries. Three patients who sustained gunshot wounds of the hand with loss of the thumb metacarpal and extensive soft tissue were treated with a groin flap that included the iliac crest. Bony union was rapid and thumb stability was excellent in all patients 3 months after initial reconstruction. The advantages of the osteocutaneous flap include the ability to: (1) supply vascularized bone to what is frequently a poor recipient bed for a bone graft, (2) reconstruct both soft tissue and bony defects simultaneously, and (3) be used in facilities without capability for microvascular surgery.
Effect of glucan and other adjuvants on the clearance of radiolabeled tumor cells from mouse lungs.
The iv injection of two forms of glucan (DiLuzio and Yamamura), Corynebacterium parvum, or bacillus Calmette-Guérin (BCG) caused a significant increase in the rate and extent of clearance of subsequently injected radiolabeled T1699 carcinoma cells from the lungs of syngeneic DBA2 mice. Dose-response curves were obtained for each agent, the relative rates of clearance of radiolabeled cells were established, and preliminary sequential comparative studies were undertaken. The optimum dose for C. parvum appeared to be lower than for DiLuzio glucan which appeared to be lower than for Yamamura glucan or BCG. The results indicated that at optimum doses one form of glucan (DiLuzio) was as effective as C. parvum and more effective than BCG or a second form of glucan (Yamamura), with respect to the time for the genesis, the magnitude, and the length of time of the response. Very preliminary experiments with a highly malignant and poorly immunogenic cell line of B16 melanoma in syngeneic C57BL/6J mice demonstrated a correlation between an increased level of clearance of radiolabeled cells and a reduced number of subsequent macroscopic lung tumor nodules.
Infant feeding and blood acid-base status.
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Gentamicin and carbenicillin penetration into the septic joint.
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Report of the ad hoc committee on acid-base methodology.
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Postpolio syndrome.
The recurrence of symptoms many years after the rehabilitation of individuals who survived the acute illness, poliomyelitis, is a major concern. The purpose of this article is to provide information to the nurse practitioner (NP), who, as a primary health care provider, may be the first health professional to encounter persons with such complaints. Although no cure has been identified, diagnosis and treatment is available and is important to the psychosocial well-being of those who suffer from postpolio syndrome. This article reviews research on the syndrome including etiology, pathophysiology, symptoms and management, psychological issues, and the role of the aging process. Some areas where further research is indicated are also identified.
Mobile chest radiography: improving image quality.
Mobile examinations present special challenges yet require the same diagnostic quality as exams performed in the radiology department. This article describes a study designed to identify common errors in mobile chest radiography. The authors identify 3 areas of particular concern: rotation, anatomy not centered to the film and distortion. Possible solutions are suggested and discussed.