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Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 469 records · Page 26Linked to original sources
PubMed1992

The risk of subarachnoid and intracerebral hemorrhages in blacks as compared with whites.

BACKGROUND: Stroke is an important cause of death among blacks, and intracerebral and subarachnoid hemorrhages account for nearly half of all early deaths from stroke. The present study investigates whether blacks and whites differ in their risk of having either intracerebral or subarachnoid hemorrhage. METHODS: We reviewed the medical records, autopsy reports, and CT scans of all patients suspected of having had an intracerebral or subarachnoid hemorrhage during 1988 among the nearly 1.3 million people in the Greater Cincinnati metropolitan area. RESULTS: There were 221 cases of first spontaneous intracranial hemorrhage among 1,086,462 whites (159 intracerebral and 62 subarachnoid hemorrhages), and 45 cases among 171,718 blacks (27 intracerebral and 18 subarachnoid hemorrhages). Blacks had 2.1 times the risk of subarachnoid hemorrhage of whites (95 percent confidence interval, 1.3 to 3.6) and 1.4 times the risk of intracerebral hemorrhage (95 percent confidence interval, 0.9 to 2.1). In those under the age of 75, the risk of intracerebral hemorrhage among blacks was 2.3 times that of whites (95 percent confidence interval, 1.5 to 3.6), whereas the risk among blacks 75 or older was one fourth that of whites (95 percent confidence interval, 0.1 to 0.8). Deaths within 30 days of intracerebral or subarachnoid hemorrhage accounted for 1.9 years of life lost per 1000 blacks under 65 years of age, as compared with 0.5 year per 1000 whites. CONCLUSIONS: Young and middle-aged blacks have a substantially higher risk of subarachnoid or intracerebral hemorrhage than whites of similar age. These types of stroke are important causes of excess mortality among young and middle-aged blacks.

Adult↗
PubMed1992

Instrumentation for the breath-by-breath determination of oxygen and carbon dioxide based on nondispersive absorption measurements.

This paper describes the development and evaluation of instrumentation for the breath-by-breath determination of oxygen and carbon dioxide in respiratory gases. The method is based on nondispersive absorption and uses the 145-nm absorption band for detection of oxygen and the 4.3-micron band for detection of carbon dioxide. A xenon discharge lamp with a sharp band at 147 nm was chosen as the source for the determination of oxygen, and a carbon dioxide discharge lamp with a sharp band at 4.3 micron was chosen for determination of carbon dioxide. A vacuum photodiode was used as the detector for oxygen, and a photoconductive cell with a built-in interference filter was used for detection of carbon dioxide. Plots of absorbance (A) vs concentration (C, %) were linear for oxygen and were nonlinear for carbon dioxide. Typical least-squares calibration equations were A = 0.020C + 0.02 for oxygen (0-100%) and A = 0.0012C2 + 0.050C + 0.008 for carbon dioxide (0-8%). Comparisons of computed (y) vs prepared (x) values for the concentrations given above were linear for both gases, yielding y = (1.00 +/- 0.01)x - 0.13 +/- 0.73 for oxygen and y = (1.07 +/- 0.02)x - 0.04 +/- 0.06 for carbon dioxide. The standard deviations were 1.2% at 50% oxygen and 1.5% at 4% carbon dioxide. Records are presented to illustrate breath-by-breath monitoring of these gases in a healthy subject.

Absorption↗
PubMed1992

Anticentromere antibody as a predictor of digital ischemic loss in patients with systemic sclerosis.

OBJECTIVE: To determine the clinical and serologic risk factors for digital ischemic events in patients with systemic sclerosis (SSc). METHODS: Retrospective review of clinical and laboratory data and review of current clinical status of 98 patients with SSc, seen between 1985 and 1990. RESULTS: Amputation of 1 or more digits due to ischemia occurred in 20.4% of the patients; 9.2% had multiple digit loss. Sclerodactyly alone and anticentromere antibody (ACA) were associated with loss of 1 or more digits. Age, smoking status, duration of disease, or duration of Raynaud's phenomenon were not predictive for loss of digits. CONCLUSION: Patients with limited SSc who are positive for ACA have an increased risk of major peripheral vascular occlusive disease.

Adult↗
PubMed1992

Ambulatory measurement of oesophageal function: clinical use of a new pH and motility recording system.

Conventional oesophageal manometric studies are open to criticism in that they take place on fasted immobile subjects in the artificial setting of a motility laboratory. A new 24-h pH and motility recording system combined with computerized data analysis was used to study patients with gastro-oesophageal reflux disease and oesophageal motor abnormalities under ambulant conditions. Acid reflux episodes were found to be precipitated by a variety of events with recognizable pressure patterns. Acid clearance abnormalities were demonstrated in patients with erosive oesophagitis but were confined to those with abnormal oesophageal motor function. Improved diagnostic accuracy was demonstrated in the recognition of oesophageal motor disorders.

Circadian Rhythm↗
PubMed1992

Chronic treatment with 1-aminocyclopropanecarboxylic acid desensitizes behavioral responses to compounds acting at the N-methyl-D-aspartate receptor complex.

Functional antagonists at the N-methyl-D-aspartate (NMDA) receptor complex produce anti-depressant-like actions in preclinical models. Thus, an injection of a glycine partial agonist (1-aminocyclopropanecarboxylic acid; ACPC), a competitive NMDA antagonist (2-amino-7-phosphonoheptanoic acid; AP-7) or a use-dependent cation channel blocker (MK-801) reduced immobility in the forced swim test (FST) with efficacies comparable to imipramine (Trullas and Skolnick 1990). Seven daily injections of ACPC (200-400 mg/kg) abolished the effects of both this compound (200-1200 mg/kg) and AP-7 (200-300 mg/kg) in the FST. The loss in effectiveness of ACPC required 7 days of treatment to become fully manifest, and was reversed by discontinuing treatment. Other agents active in the FST (e.g. MK-801, imipramine, and nifedipine) were unaffected by this regimen. Moreover, ACPC and AP-7 remained active in the FST following repeated injections of MK-801, AP-7, or imipramine. Chronic treatment with ACPC did not affect its actions in the elevated plus-maze, but significantly attenuated the convulsant and lethal effects of NMDA (125 mg/kg). Tissue levels of ACPC indicate the modified behavioral responses produced by chronic treatment are not attributable to pharmacokinetic factors. These findings suggest repeated administration of ACPC may effect an "uncoupling" of NMDA and glycine receptors, resulting in an apparent desensitization of the behavioral actions of substances acting at these sites.

2-Amino-5-phosphonovalerate↗
PubMed1992

Steroid acne after orthognathic surgery.

Steroid acne is a common unwanted effect in patients undergoing corticosteroid therapy. Eight women in a series of 1276 adult patients had acne after orthognathic surgery in which short-course parenteral corticosteroid therapy was used to reduce postoperative swelling. Steroid-induced acneiform eruption is different from acne vulgaris in that the former usually resolves on its own, without scar formation, after withdrawal of the drug.

Acne Vulgaris↗
PubMed1992

Adverse reactions of low osmolality contrast media during cardiac angiography: a prospective randomized multicenter study.

A multicenter study was performed to determine the incidence of adverse reactions to two contrast media with similar low osmolality during cardiac angiography. The study was of a randomized double-blind design comparing ioxaglate (an ionic dimer) and iopamidol (a nonionic compound) and included 500 patients; 250 patients received ioxaglate and 250 iopamidol. There were 58 adverse reactions attributed to the contrast media in the ioxaglate group and 29 in the iopamidol group (p less than 0.001). Chest pain occurred in 11 patients in the ioxaglate group compared with 5 in the iopamidol group (p = 0.123). Nausea or vomiting was present in 20 and 2 patients, respectively (p less than 0.0003). Allergic adverse reactions, such as bronchospasm, urticaria and itching, occurred in 15 of the ioxaglate group and only 1 of the patients receiving iopamidol (p less than 0.0007). Fifty-two patients in the ioxaglate group had a known allergic history (not to contrast medium) or asthma, whereas 77 receiving iopamidol had a similar history. Seven of the 52 ioxaglate-treated patients developed an allergic adverse reaction compared with none of the 77 in the iopamidol group (p = 0.001). Of 41 patients receiving ioxaglate who were premedicated with diphenhydramine, 4 had an allergic adverse event. In the iopamidol group 45 patients received similar premedication and none had an allergic adverse reaction (p less than 0.03). Thus, this multicenter study shows that adverse reactions occur more often with ioxaglate than with iopamidol and that patients with an allergic history have a greater risk with ioxaglate therapy compared with iopamidol.

Adult↗
PubMed1992

Neuropeptides within the nucleus tractus solitarii modulate the central cardiovascular control process.

Local administration of small amounts of vasopressin, angiotensin or endothelin into the nucleus tractus solitarii elicits similar decreases in blood pressure and heart rate. These central effects oppose the peripheral action of these hormones on the cardiovascular system. The baroreceptor-heart-reflex, however, is influenced differentially: vasopressin and angiotensin II enhances the sensitivity of the reflex but angiotensin III impairs it. In this way the cardiovascular system may be adjusted to different demands including those related to electrolyte and fluid homeostasis.

Angiotensin II↗
PubMed1992

Removal of intramedullary rods after femoral shaft fracture.

We are reporting a retrospective review of the removal of 60 intramedullary rods in 58 patients. All fractures had healed at the time of rod extraction. The implant was removed from 34 asymptomatic patients (36 femurs). Twenty-four patients (24 femurs) had preoperative symptoms attributed to the femoral rod. Fourteen patients had symptoms about the greater trochanter preoperatively, five patients had symptoms referable to the knee, and five had infections about the femoral implant. Problems encountered included broken rods in five femurs, one of which was not apparent on preoperative radiographs. There were six patients (six femurs) who required further hospital care for postoperative hematomas. The development of a significant hematoma was not related to the location of the fracture, the presence of interlocking devices requiring removal, the length of time since injury, the performance of this procedure as an inpatient or outpatient, or the presence or absence of a functional drain. Of the 10 patients (10 femurs) who had proximal heterotopic ossification Brooker stage 2 or greater, wound hematomas developed in four patients (40%). There were no refractures. Although there may be an indication for rod removal, we do not recommend the procedure in asymptomatic patients.

Adolescent↗
PubMed1992

Blunt colonic injury--a multicenter review.

During the past decade there has been a shift in the management of injuries of the colon to primary repair without a protective diverting colostomy. Unfortunately, reports concerning this practice contain relatively few patients with blunt trauma and it is unclear whether the principles established for penetrating injury should be applied in the setting of blunt colon injury. A retrospective review of 54,361 major blunt trauma patients admitted to nine regional trauma centers from January 1, 1986, through December 31, 1990, was conducted. Statistical analysis of the data collected regarding 286 (0.5%) of these patients who suffered colonic injury revealed: (1) injury to the colon is found in more than 10% of patients undergoing laparotomy following blunt trauma; (2) available diagnostic modalities are unreliable in detecting isolated colonic pathology; (3) primary repair of full-thickness injuries or resection and anastomosis may be safely performed without diversion; (4) gross fecal contamination is the strongest contraindication to primary repair. Further, delay of surgery, shock, and the timing of antibiotic administration were not associated with significantly increased morbidity.

Abbreviated Injury Scale↗
PubMed1992

Anti-inflammatory effects of nedocromil sodium: inhibition of alveolar macrophage function.

The IgE-dependent activation of mononuclear phagocytic cells through their capacity to express low affinity IgE receptors (Fc epsilon RII) has been proposed as a mechanism for the development of airways inflammation in allergic asthma. This Fc epsilon RII expression leads to the IgE-dependent production of the potent pro-inflammatory cytokines IL-1 beta and TNF-alpha. Expression by monocytes of Fc epsilon RII is regulated by several cytokines including interleukin-4, gamma- and alpha-interferons, and granulocyte-macrophage and macrophage colony stimulating factors. An anti-inflammatory effect of nedocromil on monocytes has been proposed as a possible mechanism for its anti-asthma activity. We therefore investigated the capacity of nedocromil to modulate mononuclear phagocyte Fc epsilon RII expression and cytokine production. We used an anti-Fc epsilon RII antibody and flow cytometric analysis to assess the capacity of nedocromil to modulate cytokine-induced Fc epsilon RII expression in normals and asthmatics. Monocytes, THP-1 monocyte leukaemia cells, and alveolar macrophages were exposed to varying concentrations of these cytokines for 48 hr at 37 degrees C with or without the additional presence of nedocromil (1-10 microM) and the per cent of monocytes expressing Fc epsilon RII was determined. No changes in Fc epsilon RII expression were observed. Subsequently, we investigated the capacity of nedocromil to affect the capacity of IgE plus anti-IgE complexes, allergen, and LPS (16 hr/37 degrees C) to stimulate IL-1 beta and IL-6 production. No changes were observed when nedocromil was applied concomitant with the stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Noncompetitive inhibition of N-methyl-D-aspartate by conantokin-G: evidence for an allosteric interaction at polyamine sites.

Conantokins T and G are polypeptide toxins present in snails of the genus Conus. These substances were recently reported to act as N-methyl-D-aspartate (NMDA) antagonists. In the present study, we examined the possible mechanisms producing this antagonism. Conantokin-G inhibited spermine- and spermidine-stimulated [3H]MK-801 binding to extensively washed rat forebrain membranes in a noncompetitive manner with IC50 values of approximately 507 and approximately 946 nM, respectively. In contrast, glutamate-enhanced [3H]MK-801 binding was unaffected by conantokin-G concentrations of less than or equal to 20 microM. At concentrations greater than or equal to 5 microM, conantokin-G effected a modest, noncompetitive inhibition of glycine-stimulated [3H]MK-801 binding and also produced a small enhancement of basal [3H]MK-801 binding. Conantokin-G reduced (IC50 approximately 1.08 microM) the NMDA-stimulated accumulation of cyclic GMP in cerebellar granule cell cultures to basal values, but did not affect kainate-mediated increases in cyclic GMP. These findings indicate that conantokin-G acts as a noncompetitive NMDA antagonist through an allosteric inhibition of polyamine responses. The neurochemical profile of this polypeptide is distinct from previously described noncompetitive NMDA antagonists.

Animals↗
PubMed1992

Adoptively transferred anti-idiotype pulsed B cells mediate autoimmune myocarditis.

Syngeneic mice receiving adoptively transferred enriched B cells or splenocytes pulsed in vitro with polyclonal anti-idiotypic antibodies (anti-Ids) against anti-CVB3 virus antibodies developed coxsackievirus B3 antigen-binding and virus-neutralizing antibodies during a 30-day period, in addition to overt expression of autoimmune myocarditis. Adoptive transfer of anti-Id pulsed T cells resulted in delayed appearance and transient expression of antiviral antibodies, and antiviral antibodies were marginal to absent in syngeneic animals receiving anti-Id pulsed macrophage populations. Proliferation analysis of recipient splenocytes indicated lack of proliferative capacity in response to monoclonal or polyclonal anti-Ids and only marginal proliferative capacity in response to coxsackievirus B3 virus antigen(s). In vitro assessment of delayed hypersensitivity in recipient animals demonstrated some specific immunity to anti-Ids in recipients receiving splenocytes or T cells. Anti-Ids expressing mimicry for heart-associated and/or viral antigen(s) interacting with B cells or other accessory cells suggest an autoantibody or anti-Id triggering of B-cell-mediated mechanisms involved in the development of myocarditis.

Animals↗
PubMed1992

Social care services for patients with HIV at a London teaching hospital; an evaluation.

OBJECTIVE: To investigate outpatients' use of, and satisfaction with social care services in an HIV unit. DESIGN: Survey of patients with HIV infection using self administered questionnaire. SETTING: Outpatient HIV clinics at the Royal Free Hospital, London, March-April 1991. MAIN OUTCOME MEASURES: Patients' social circumstances, use or intended use of social care services and satisfaction with social care services. RESULTS: The greatest demand was for counselling about coping with HIV (38% of respondents), available medical treatment (24%), counselling for the HIV test (33%), psychological support for emotional (24%) or relationship problems (16%), advice about housing (24%) and financial matters (20%). In general, the use of social care services by men and women was similar. Twice as many men, however, sought help with payment of domestic bills, compared with women. Women were more likely to seek advice about financial benefits, obtaining sterile injecting equipment and discuss sleep and relationship problems. Thirty eight percent of patients were unemployed. Overall, 84% thought the service was good or excellent. Although less than 40% of patients currently used any one service, 60% thought they would use these services in the future. CONCLUSION: The greatest demand for social care services was for coping with HIV, housing and financial matters, and HIV test counselling. More than half the patients stated that they would probably need social care services in future.

Adaptation, Psychological↗