Biomedical subjects

S M Miller

Publications and source records attributed to S M Miller.

At least 91 records · Page 5Linked to original sources

PubMed1996

Human immunodeficiency virus-associated atypical mycobacterial skeletal infections.

The clinical and laboratory features of six human immunodeficiency virus (HIV)-positive patients with atypical mycobacterial skeletal infections, seen at a county outpatient HIV facility or university outpatient clinic, are reviewed and compared with other reported cases. Atypical mycobacterial skeletal infections are a manifestation of advanced HIV disease, with most cases having CD4 counts < 100/mm3 at the time these infections become clinically apparent. Multiple sites are frequently involved, and concomitant skin infection with the same organism is common, especially with Mycobacterium haemophilum. The incidence of atypical mycobacterial skeletal infection in HIV-infected individuals was significantly higher than in the general county hospital district patient population, whereas the frequency of Myobacterium tuberculosis skeletal infection did not differ significantly between the two populations. The clinician therefore should maintain a high index of suspicion for atypical mycobacteria in a patient presenting with skeletal infection in the setting of a markedly depressed CD4 count.

AIDS-Related Opportunistic Infections↗

PubMed1996

A randomized trial of breast cancer risk counseling: interacting effects of counseling, educational level, and coping style.

The authors evaluated the impact of individualized breast cancer risk counseling (BCRC) on breast-cancer-specific distress and general distress in 239 women with a family history of breast cancer. Following a baseline assessment of demographics, risk factors, coping styles, and distress, participants were assigned randomly to receive either BCRC or general health education (GHE; i.e., control group). After controlling for education level, women who received BCRC had significantly less breast-cancer-specific distress at 3-month follow-up compared with women who received GHE. A significant Education Level x Treatment Group interaction indicated that the psychological benefits of BCRC were greater for women with less formal education. In both the BCRC and GHE groups, participants who had monitoring coping styles exhibited increases in general distress from baseline to follow-up.

Adaptation, Psychological↗

PubMed1996

Applications of the monitoring process model to coping with severe long-term medical threats.

Guided by the monitoring process model (MPM), the authors explored the illness responses of 2 samples: high monitors (who are cognitively vigilant to and amplify threat-related cues) and low monitors (who avoid them and blunt their impact). Both samples-101 women with human papillomavirus-related precancerous cervical dysplasia and 75 HIV-infected gay men-were undergoing long-term medical follow-up and management. Structural equation analysis showed an adequate fit of the MPM to the data within each sample, supporting the model's heuristic value: High monitors experienced greater disease-related intrusive ideation, which triggered greater avoidant ideation to forestall panic, particularly in the more threatened HIV-positive sample. However, efforts to avoid disturbing intrusive thoughts were ineffective, requiring increasingly extreme defensive strategies (i.e., denial and mental and behavioral disengagement).

Adaptation, Psychological↗

PubMed1996

Applying cognitive-social theory to health-protective behavior: breast self-examination in cancer screening.

This article applies recent developments in cognitive-social theory to health-protective behavior, articulating a Cognitive-Social Health Information Processing (C-SHIP) model. This model of the genesis and maintenance of health-protective behavior focuses on the individual's encodings and construals, expectancies, affects, goals and values, self-regulatory competencies, and their interactions with each other and the health-relevant information in the course of cognitive-affective processing. In processing health information, individuals are assumed to differ in both the accessibility of these mental representations and the organization of relationships among them. In this article, the model is applied to analyze and integrate the often-confusing findings on breast self-examination in cancer screening. Implications are considered for assessments and interventions to enhance adherence to complex, long-term, health-protective regimens, tailored to the needs and characteristics of the individual.

Breast Neoplasms↗

PubMed1996

Palmaroproximal approach for arthrocentesis of the proximal interphalangeal joint in horses.

A technique was developed for arthrocentesis of the palmaroproximal pouch of the pastern joint. The landmark for percutaneous puncture is a 'V' shaped depression formed by the palmar aspect of the proximal phalanx (P1) dorsally, an eminence associated with the attachment of the collateral ligaments to P1 and the middle phalanx distally and the insertion of the lateral branch of the superficial digital flexor tendon palmarodistally. Comparison of arthrocentesis between the palmaroproximal approach and the traditional dorsal approach in 8 cadavers and 8 horses demonstrated that the palmaroproximal approach was associated with less needle manipulation, greater injection volume (horses) and frequent synovial fluid flow.

Animals↗

PubMed1996

Electrophysiological effects of nitric oxide in mouse superior mesenteric ganglion.

Effects of nitric oxide (NO) generated from sodium nitroprusside (SNP) on neurons of mouse superior mesenteric ganglion (SMG) were studied in vitro using intracellular recording techniques. SNP solutions caused a membrane hyperpolarization in the majority (64%) of the neurons tested or a hyperpolarization followed by a depolarization in 8% of the neurons tested. The SNP-induced hyperpolarization persisted in a low-Ca2+ high-Mg2+ solution, indicating a direct effect of NO on the postsynaptic membrane. The hyperpolarizing effect of SNP was reduced or abolished by oxyhemoglobin. Electrical stimulation of the colonic nerves evoked a late slow excitatory postsynaptic potential (late sEPSP) in a population of neurons in normal Krebs solution. The amplitude of the late sEPSP was significantly enhanced in the presence of NG-nitroL-arginine, a NO synthase inhibitor. The results, particularly those observed with the NO synthase inhibitor, suggest that endogenous NO was released in the mouse SMG by repetitive nerve stimulation and that it modulated slow synaptic transmission, presumably by a direct action on ganglionic neurons.

Animals↗

PubMed1996

Color Doppler sonography of the prostate.

Digital rectal examination, prostate-specific antigen and transrectal sonography (TRS) are the main diagnostic tools for evaluating men at risk for carcinoma of the prostate (PCa). PCa has a hypoechoic echo pattern via TRS in 60- 85% of cases. Hypoechoic areas are observed, however, in benign prostatic hyperplasia (BPH) as well. For this reason, TRS yields a low specificity and sensitivity in detecting PCa in screening programs. Additional data, independent of the grey scale information available via TRS, can be obtained by using the innovative technology of color Doppler sonography. This imaging modality allows simultaneous real-time sonographic visualization and evaluation of vascular structures. The present study analyzes to what extent the analysis of blood flow perfusion of prostatic parenchyma can provide further information concerning the pathologic alterations occurring in abnormal prostate tissue. Blood flow phenomena were reproducibly demonstrated in the prostate and in the periprostatic tissue with the color-coded Doppler sonography (CD-TRS). 31 patients with the diagnosis of BPH could be separated into two different groups according to the findings with TRS and CD-TRS. In contrast, patients with histologically proven PCa (n = 16) had subjectively increased perfusion rates. Blood flow phenomena were analyzed using computer-calculated resistive index and pulsatility index as evaluations of flow and frequency. A preliminary analysis of the wave-form characteristics shows that flow in the prostate gland is associated with a high resistive index in both PCa and BPH. The mean frequency demonstrated in the pulsatility index appears to be high in PCa, but low in BPH cases. Further studies are needed to verify the described factors' abilities to differentiate prostate tissue as either PCa or BPH.

Humans↗

PubMed1996

Cat pancreatic neurons: morphology, electrophysiological properties, and responses to 5-HT.

Light and confocal microscopy was used to study the anatomy and morphology of cat pancreatic ganglia. Intracellular microelectrodes were used to examine the electrophysiological properties of neurons in the head, body, and tail regions of the pancreas and to compare their responses to 5-hydroxytryptamine (5-HT). Pancreatic ganglia were oval shaped, joined by interconnecting nerves. Several head to tail gradients were found: (1) ganglion cell numbers decreased from head to tail; (2) the incidence of ongoing synaptic activity was higher for neurons located in the head region; (3) ganglion neurons in the head region received a greater number of converging synaptic inputs; (4) a greater percentage of neurons in the head region responded to 5-HT; (5) a greater percentage of neurons in the head region exhibited depolarizing responses mediated by 5-HT3 receptors; and (6) late slow-excitatory postsynaptic potentials recorded from neurons in the head region were more often antagonized by 5-HT1P receptor antagonists. It was concluded that cat pancreatic ganglia are sites of convergence and integration of synaptic inputs arriving from multiple sources. Serotonergic inputs from enteropancreatic nerves, if they exist in the cat pancreas, would be expected to have a significant influence on the excitability of neurons located in the head region compared to neurons located in the tail region of the pancreas.

Animals↗

PubMed1995

Expression of immediate early genes in rat gastric myenteric neurones: a physiological response to feeding.

1. Expression of the immediate early genes c-fos, c-jun and c-myc in rat stomach in response to feeding and gastric distension was examined by Northern blot analysis and in situ hybridization. 2. Refeeding of fasted rats induced a transient increase in c-fos mRNA abundance in gastric corpus and antrum that was sixfold within 15 min and declined within 4 h. The response was not mediated by gastrinergic or muscarinic cholinergic mechanisms; it was reduced but not abolished by hexamethonium. No changes in expression of c-jun, c-myc or the constitutively expressed protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were observed. 3. In conscious rats prepared with a gastric fistula, gastric distension with nutritive and non-nutritive solutions at a physiological pressure for 30 min induced expression of c-fos, c-jun and c-myc, but not GAPDH. 4. Messenger RNA encoding c-fos was localized by in situ hybridization to gastric myenteric neurones of animals that underwent gastric distension, but not of undistended controls. 5. The results suggest that expression of c-fos in gastric myenteric neurones is an early response to the physiological stretching of the stomach wall that accompanies feeding. With supraphysiological distension, other immediate early genes may be recruited.

Animals↗

PubMed1995

2'-fluoro-2'-deoxy-D-arabinoflavin: characterization of a novel flavin and its effects on the formation and stability of two-electron-reduced mercuric ion reductase.

With the goal of generating a novel fluorine-containing flavin analogue with a reduction potential the same as normal flavin, 2'-fluoro-2'-deoxy-D-arabinoflavin has been synthesized. In its riboflavin and FAD forms, UV-visible spectral properties are similar to those of normal flavins, and tight binding to riboflavin binding protein and mercuric ion reductase occurs with very similar spectral changes. The reduction potential of the 2'-FaFAD analogue is determined to be -207 mV compared with -206 mV for FAD, indicating that the intervening 1'-methylene group insulates the redox-active isoalloxazine from the 2'-fluorine. With the intent of using the analogue as a fluorine NMR probe of the active site environments of two-electron-reduced mercuric ion reductase, apoenzyme was reconstituted and its behavior under reducing conditions examined. Whereas with normal enzyme, addition of two electrons gives rapid formation of a charge-transfer species where FAD remains oxidized and a disulfide is reduced to a thiol/thiolate pair, with the 2'-FaFAD enzyme, addition of two electrons gives rapid reduction of the flavin followed by slow transfer of electrons to the disulfide with very little development of the typical charge-transfer absorption. Analysis of crystal structure data suggests that having the fluorine in the alternate arabino stereochemistry places it much nearer the flavin-proximal cysteine/cystine sulfur, where it may inhibit both electron transfer from reduced flavin and the charge-transfer interaction between reduced thiolate and FAD.

Apoenzymes↗

PubMed1995

Monitoring versus blunting styles of coping with cancer influence the information patients want and need about their disease. Implications for cancer screening and management.

BACKGROUND: Two main psychologic coping styles for dealing with cancer and other health threats have been identified: monitoring (attending to) or blunting (avoiding) potentially threatening information. This article reviews results and implications from this research relevant to cancer screening and management. METHODS: The Monitor-Blunter Style Scale has been used extensively to assess and categorize patients with regard to these coping styles to predict their differential responses to various cancer-related screening and management regimens. RESULTS: Patients characterized by a monitoring coping style generally are more concerned and distressed about their cancer risk, experience greater treatment side effects, are more knowledgeable about their medical situation, and are less satisfied with and more demanding about the psychosocial aspects of their care. They also prefer a more passive role in clinical decision making, are more adherent to medical recommendations, and manifest greater psychologic morbidity in response to cancer-related threats. CONCLUSIONS: Patients fare better (psychologically, behaviorally, and physiologically) when the information they receive about their medical condition is tailored to their own coping styles: generally those with a monitoring style tend to do better when given more information, and those with a blunting style do better with less information. However, patients with a monitoring style who are pessimistic about their future or who face long term, intensely threatening, and uncontrollable medical situations may require not just more information, but also, more emotional support to help them deal with their disease.

Attitude to Health↗

PubMed1995

Nitric oxide is a neuromodulator in cat pancreatic ganglia: histochemical and electrophysiological study.

This study examined the distribution of NADPH-diaphorase (NADPH-d) activity in cat pancreatic ganglia and the electrophysiological effects of nitric oxide (NO) donors, NO and the effect of endogenously released NO. The majority (64%) of pancreatic ganglion neurons stained positive for NADPH-d. Large nerve trunks contained numerous non-varicose NADPH-d positive fibers. NADPH-d positive nerve fibers within individual ganglia were varicosed. L-Arginine, sodium nitroprusside and NO, applied in the vicinity of the impaled neuron, evoked a hyperpolarizing response and initiated fast excitatory postsynaptic potentials (EPSPs) in the majority of neurons tested. The hyperpolarizing response was not affected by low Ca2+ (0.1 mM), high Mg2+ (15 mM). Pretreatment with nitro-L-arginine increased the amplitude of slow EPSPs in about 50% of neurons tested. These results support the hypothesis that NO plays a role in ganglionic transmission in the cat pancreas.

Animals↗

PubMed1995

Coping disposition, perceived risk, and psychological distress among women at increased risk for ovarian cancer.

The authors examined predictors of psychological distress among women who were at increased risk for ovarian cancer. Participants were 103 women who had at least 1 first degree relative with ovarian cancer. Specifically, the authors tested the relationship between the dispositional attentional style of monitoring (the tendency to scan for threat-relevant information), perceptions of risk for ovarian cancer, intrusive thoughts regarding ovarian cancer, and psychological distress. Overall, this sample exhibited moderately high levels of psychological distress. High scores on monitoring were associated with high perceived risk for ovarian cancer and elevated levels of intrusive thoughts and psychological distress. Finally, the authors proposed and tested a path model describing the interrelationships between these variables. The results of this study are discussed in terms of their implications for treating the psychological distress associated with being at increased risk for ovarian cancer.

Adaptation, Psychological↗

PubMed1995

Patterns of children's coping with an aversive dental treatment.

Children's disposition to monitor for threat-relevant cues predicted their coping strategies and levels of distress when dealing with invasive dental work. High monitors reported that they had engaged in greater sensory vigilance and avoidance strategies during treatment. Neither the tendency to monitor nor children's sensory vigilance was related to videotape observations of their attention deployment. High monitors reported increased anxiety and were rated as more anxious, particularly when they also engaged in high avoidance. Children's reports of question asking were related to videotape observations of question asking. In addition, children who asked more questions were rated as more anxious and disruptive during treatment. Individual differences in how children deal with a familiar--but largely uncontrollable--stressor are discussed, particularly with respect to the encounter phase of coping.

Adaptation, Psychological↗

PubMed1995

Case studies: profiles of women recovering from drug addiction.

These case studies profile two women who abused alcohol and other drugs while pregnant and describes their recovery from the addiction. They examine from an ecological framework the women's experience with drug addiction, treatment, and recovery and recounts their situations through each [1]. This research uses in-depth interviews as its data source. Further, these studies contain direct quotes from the women orally sharing their thoughts. Their quotes are not edited or changed by any kind of systems for the purpose of capturing the thoughts of the women.

Adaptation, Psychological↗

PubMed1995

Quantitative electroencephalographic evaluation to determine the quality of analgesia during anesthesia of horses for arthroscopic surgery.

We compared the anesthetic combination of detomidine, ketamine, and halothane in control horses not undergoing apparently painful procedures with that in horses during arthroscopic surgery. The effectiveness of this regimen in suppressing neurologic response to surgery was, thus, evaluated. In this study, significant differences were not observed in electroencephalographic total amplitude, spectral edge, or beta-to-delta frequency ratio between surgically treated and nonsurgically treated (control) horses. On the basis of its attenuation of encephalographic responses, we conclude that detomidine (20 micrograms/kg of body weight, IV) and ketamine (2.2 mg/kg, IV) induction of anesthesia followed by maintenance with halothane is an effective regimen for control of pain in horses during arthroscopic surgery. The insignificant frequency changes observed without any other signs of inadequate anesthesia or pain may indicate a surgical stress response. We hypothesize that brain activity monitoring may give an earlier index to initiation of surgically induced stress than do hormonal responses, because endocrine alterations are not as rapidly perceived as is the electroencephalogram. Analysis of spectral edge frequency changes could be used to evaluate anesthetic regimens to find those that cause the least stress to the CNS during surgery in horses. Differences in species responses to an anesthetic agent or the regimen's effectiveness in prevention of pain during surgery may be identified by adoption of the study model. Evaluation of cardiopulmonary variables during anesthesia, with and without surgery, did not reveal any alterations that would be relevant to CNS responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesia↗

PubMed1994

Mechanism of p-hydroxyphenylacetate-3-hydroxylase. A two-protein enzyme.

p-Hydroxyphenylacetate-3-hydroxylase purified from Pseudomonas putida is a two-protein enzyme requiring a flavoprotein and a coupling protein for productive hydroxylation (Arunachalam, U., Massey, V., and Vaidyanathan, C. S. (1992) J. Biol. Chem. 267, 25848-25855). This paper presents information on the mechanism of the enzyme from absorbance and fluorescence stopped-flow studies. The reduction of the substrate-free flavoprotein by NADH was slow and was not altered by the presence of the coupling protein. In contrast, the coupling protein has a dramatic effect in the oxidative half-reaction. The flavoprotein when present alone, both in the absence and presence of the aromatic substrate, reacts in a second-order fashion with oxygen to form oxidized flavoprotein, with no indication of flavin-oxygen intermediates. However, an intermediate identified as the C4a-flavin hydroperoxide is stabilized when the flavoprotein-coupling protein complex reacts with oxygen in the absence of the aromatic substrate, p-hydroxyphenylacetate, and at least three flavin-oxygen intermediates, attributed to the anionic (I) and protonated (I*) forms of the flavin hydroperoxide and the hydroxyflavin (III), are formed in the oxidative half-reaction in the presence of the aromatic substrate. A reaction mechanism for the two-protein complex is proposed in which the aromatic substrate has little effect on the rate of reduction of the enzyme flavin but has strict control in the oxidative half-reaction. In this phase the flavin hydroperoxide is remarkably stable in the absence of the substrate but disappears rapidly upon encountering the aromatic substrate.

Azides↗

PubMed1994

Con: antiarrhythmic drugs should not be used to suppress ventricular ectopy in the perioperative period.

The alterations in autonomic tone imposed by the conduct of anesthesia and surgery predispose patients to ventricular ectopy. It is important to initially view any ectopy as a warning sign and promptly check the adequacy of ventilation and oxygenation. Most commonly an inadequate depth of anesthesia, surgical manipulation or electrolyte abnormality will be causative. Treatment of this underlying problem will usually suffice to terminate the ectopy. Importantly, many patients have preexisting, chronic, complex ventricular ectopy that gets revealed because of perioperative electrocardiographic monitoring. All available pharmacologic agents have significant adverse side effects. To date, all investigations examining outcome of suppression of ventricular ectopy show that successful suppression of ventricular ectopy was associated with an increased mortality. Although the prognosis for patients is worse when complex ventricular ectopy is associated with cardiac structural abnormalities, the optimal therapeutic approach to such patients remains undefined. Unless new data supporting the use of antiarrhythmic drugs in the perioperative setting become available, the risk to benefit ratio is considered unfavorable.

Anti-Arrhythmia Agents↗