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C Pfeiffer

Publications and source records attributed to C Pfeiffer.

At least 55 records · Page 3Linked to original sources
PubMed1989

Acetylcholine in the crayfish optic lobe: concentration profile and cellular localization.

The crayfish optic lobe contains high levels of acetylcholine (ACh) and choline as measured with a chemiluminescent assay in small fragments of optic lobe tissue. The highest concentrations were found in the medulla externa and medulla interna (second and third optic neuromeres), which have ACh concentrations of 270 pmol/mg tissue. This concentration is about 16 times that measured in the photoreceptors and lamina ganglionaris (the first optic neuromere). Immunocytochemistry (based upon antisera to choline-glutaryl-BSA) revealed low levels of ACh-like reactivity in the lamina ganglionaris associated with the terminal arbors of centrifugal and/or tangential neurons. The most intense ACh-like reactivity was observed in monopolar neurons of the medulla externa and medulla interna. One monopolar neuron/medullary column (or about 2500 neurons/medullary neuropile) exhibited reactivity and an estimated cytoplasmic concentration of 8.1 mM.

Acetylcholine↗
PubMed1989

Cholinergic synapses and the organization of contrast detection in the crayfish optic lobe.

The actions of acetylcholine (ACh) were examined on 4 classes of multicolumnar interneurons whose dendrites lie in close proximity to the putative cholinergic transmedullary neurons described in the companion report. ACh-elicited responses in each cell type resemble visually elicited synaptic events and persist following synaptic blockade with 20 mM CoCl2. Tangential cells exhibit a hyperpolarizing response to ACh that resembles the visual response in reversal potential and dependence on extracellular chloride. The visual response is potentiated by the anticholinesterase, neostigmine (0.1 mM). Visual and carbachol-elicited responses are blocked by nicotinic ganglionic antagonists (e.g., 10(-6) M pempidine) that are 10-100 times more potent than D-tubocurarine. Medullary amacrine cells exhibit depolarizing responses to ACh (10(-6) M) and light with similar reversal potentials. The visual response is potentiated by neostigmine. Dimming fibers respond to light and ACh with a hyperpolarization that inhibits the maintained discharge. The sustaining fiber response to ACh reflects both direct responses and indirectly elicited synaptic actions. The direct action is a hyperpolarization possibly related to the visual "off-response." It is associated with an increased conductance and a reversal potential negative to the dark potential. The off-response is abolished by curare and pempidine and potentiated by neostigmine. ACh appears to orchestrate several aspects of the dual-channel contrast detection system of the optic lobe. The actions of ACh on tangential cells, amacrine cells, and dimming fibers are all consistent with the effects of a spatially localized increment in light intensity and a corresponding local release of ACh in the retinotopic columnar array.

Acetylcholine↗
PubMed1988

Uncertainty, coping, and distress following myocardial infarction: transition from hospital to home.

The purpose of this study was to examine the influence of uncertainty in illness and use of coping methods on emotional distress and recovery following myocardial infarction. A longitudinal exploratory design with measures obtained at three times was used; multiple regression was used to analyze the data. Uncertainty explained a significant amount of the variance in emotional distress prior to hospital discharge (21%), and 1 (16%) and 4 (26%) weeks after discharge. Patients reporting greater uncertainty also reported more emotional distress. One week after discharge, coping behaviors significantly added to the variance explained in distress (27%). Greater use of emotive coping behaviors was associated with higher levels of emotional distress and accounted for the majority of the variance explained by coping behaviors (23%). The findings are discussed in terms of the nature of uncertainty in health care and future model development.

Adaptation, Psychological↗
PubMed1988

A modified determination of coenzyme Q10 in human blood and CoQ10 blood levels in diverse patients with allergies.

Two situations required a modified determination of coenzyme Q10 (CoQ10) in human blood and organ tissue. Blood from patients with AIDS and cancer raised apprehensions about safety to an analyst, and the number of specimens for analysis is increasing enormously. A modified determination replaces silica gel-TLC with disposable Florisil columns, and steps were simplified to allow more analyses per unit time. Data from the modified determination are quantitatively compatible with data from older and tedious procedures. This determination was used for blood from 36 diverse patients with allergies. The mean CoQ10 blood level of these patients is not different from the mean level of so-called normal individuals, but approximately 40% (14/36) of these allergic patients had levels up to 0.65 micrograms/ml, which is the level of dying class IV cardiac patients. The biosynthesis of CoQ10 in human tissues is a complex process that requires several vitamins and micronutrients, so that countless vitamin-unsupplemented Americans may be deficient in CoQ10. The relationship of allergies to autoimmune mechanisms and immunity, and the established relationship of CoQ10 to immune states, may be a rationale for therapeutic trials of administering CoQ10 to patients with allergies who have low CoQ10 blood levels and are very likely deficient.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Attributional processes in rheumatoid arthritis patients.

In a study of 92 patients with rheumatoid arthritis, we examined patients' beliefs about the causes of their illness, disease flares, and disease remissions, and about the selective incidence of the disease. Numerous self-report measures were used to elucidate the patients' attitudes and perceptions; the tendency of patients to present themselves in socially desirable ways was taken into account and was found not to influence the study results. The causes for the illness that were most frequently cited by patients were heredity (34.7%), autoimmune factor (24.4%), personal behaviors (22.8%), and psychological stress (22.8%). Patients who were more actively searching for the causes of the illness and who continued to ask "Why me?" reported greater functional problems and a greater sense of helplessness. The most frequently cited causes for symptom flares were psychological stress (45.5%), changes in weather (34.0%), and excessive physical activity (34.1%). Symptom remissions were most frequently believed to be related to medication changes (49.4%) and the absence of psychological stress (21.0%). Several of these causal beliefs were related to perceptions of helplessness and the illness' predictability and to health care providers' assessments of disease severity and patients' psychosocial adjustment.

Adult↗
PubMed1987

Appraisals of control and predictability in adapting to a chronic disease.

In a sample of 92 patients with rheumatoid arthritis, we examined interrelations among various control appraisals, illness predictability, psychosocial adjustment, mood, and illness status. Perceiving greater personal control over the disease and symptoms and perceiving greater health-care-provider control over symptoms were associated with greater illness predictability. Patients reported more personal control over their symptoms than over the course of the disease and thought that their health care providers had more control over disease course than they did themselves. Multiple regression analyses showed that perceiving greater personal control over one's medical care and treatment was associated with positive mood and psychosocial adjustment. Negative mood was also associated with the belief that providers have greater control over the patient's daily symptoms. Patients who had a more severe disease and expressed greater personal control over its course reported greater mood disturbance and were rated as exhibiting less positive adjustment, but those who had more severe daily symptoms and expressed greater personal control over their symptoms reported less mood disturbance. These findings are discussed in terms of the possible benefits of patients' active participation in their care and the implications of perceiving personal and others' control over more or less controllable aspects of the illness, especially when the illness is more severe.

Activities of Daily Living↗
PubMed1987

Detection of aortic dissection by transoesophageal echocardiography.

The diagnostic value of a combination of transoesophageal and transthoracic echocardiography was evaluated in 21 patients with dissection of the aorta. The results were compared with those of computed tomography, aortography, and with findings at operation or necropsy or both. Transthoracic echocardiography identified three of the four patients with type I dissection, two of the five patients with type II dissection, and one of the 12 patients with type III dissection. When transoesophageal echocardiography was used as well the degree of aortic dissection was identified correctly in all 21 patients. In one patient with type I and in eight patients with type III dissection spontaneous echocardiographic contrast with a mural thrombus within the false lumen could be detected. Computed tomography was unable to demonstrate an intimal flap in one of two patients studied with type I dissection, in two of three patients with type II dissection, and in one of nine patients with type III dissection. Aortography was negative in one of two patients studied with type I dissection, two of four patients with type II dissection, and in one of eight patients with type II dissection. The whole thoracic aorta can be imaged by a combination of transthoracic and transoesophageal echocardiography. The addition of transoesophageal echocardiography to transthoracic echocardiography improves the recognition of aortic dissection. Furthermore, this examination can be performed at the bedside and the findings can be used as a basis for treatment.

Adult↗
PubMed1987

Decrease of the salt appetite of spontaneously hypertensive rats by chronic application of almitrine.

The effect of almitrine on salt appetite, water intake, and renal excretory function was investigated in conscious adult spontaneously hypertensive rats (SHR) of both sexes. The animals were kept singly in metabolic cages and given free access to food, water and 2.5% NaCl-solution. Oral administration of almitrine (0.4 mg/kg) for five days evoked an effective long-lasting suppression of voluntary salt intake and a temporary decrease of water intake. The pattern of renal electrolyte excretion was determined by the pattern of intake. The present results support the assumption that the activity of the peripheral arterial chemoreceptors plays an essential role in the maintenance of voluntary salt intake in SHR.

Almitrine↗
PubMed1987

[Diagnostic value of the transesophageal Doppler echocardiography].

Transesophageal echocardiography has been proven to be of particular value in all patients with transthoracic echocardiograms of low quality related to pulmonary emphysema, obesity and chest deformation as well as in intensive care unit patients. Similarly, transesophageal Doppler echocardiography is of particular value in all cases in which the transthoracic Doppler, due to methodological problems, is of limited value. Mitral regurgitation can be detected and quantified and flow direction described. Only in 12/25 patients with mild, 11/12 patients with moderate and 5/8 patients with severe insufficiency was regurgitation detected by transthoracic echocardiography as compared to transesophageal echocardiography with which the lesion was consistently detected. In two patients with severe and clinically-inapparent mitral regurgitation related to papillary muscle rupture, the diagnosis was established only by the transesophageal approach in an emergency situation. Atrial septal defects were detected in 8/15 patients and the size of the defect analyzed. With transesophageal Doppler echocardiography, the relation of left-to-right and right-to-left shunts could be described. In 7/16 patients with aortic dissection, true and false lumen were differentiated by analysing the flow pattern within both lumina. In 9/16 patients differentiation was enabled through delineation of the false lumen which was filled with thrombotic material. Detection of aortic regurgitation and tricuspidal regurgitation is possible but analysis of flow patterns is difficult because flow direction is nearly orthogonal to the ultrasound beam. First attempts to quantify cardiac output have been performed. For the future, transesophageal color flow Doppler mapping appears to be a most promising method.

Aortic Valve Insufficiency↗
PubMed1985

Combined medical and mechanical recanalization in acute myocardial infarction.

A technique of combined medical and mechanical recanalization was employed in 96 patients with acute transmural myocardial infarction. The mean time between onset of symptoms and admission to hospital was 170 +/- 65 min (X +/- SD). After 10 +/- 16 min, 250,000 U streptokinase was administered intravenously for 20 min. Intracoronary thrombolysis was commenced within 38 +/- 14 min. First coronary angiograms demonstrated reperfusion, an open vessel in 25/96 patients (26%). In 15/71 patients (21%) reperfusion occurred during thrombolysis therapy, before mechanical recanalization could be performed. Recanalization was achieved mechanically in 37/71 patients (52%) with occluded coronary vessels. In 8/71 patients (11%) mechanical recanalization failed but the vessel opened during thrombolysis. In 12/96 patients (12%), the coronary vessel remained occluded. Thus, reperfusion could be achieved in 88% of the patients. Reperfusion rate was 76% in the first 38 patients and 95% subsequently. After reperfusion, coronary thrombi were found in 25/96 patients (26%) but dissolved during thrombolysis in 16/25 patients (64%). Peripheral coronary embolism was observed in 3/25 patients (12%). For the whole group, reocclusion occurred in 8/84 patients (10%). By combined medical and mechanical recanalization, the recanalization rate could be increased with low reocclusion rate. Trends showed an improvement in regional and global left ventricular function in patients with anterior myocardial infarction.

Aged↗
PubMed1985

Age dependence of post-pause contractions in the ventricular myocardium of rats.

The maximal post-pause contraction has been measured in random bred albino rats by varying the contraction interval preceding this event. The amplitude of the maximal post-pause contraction as well as the duration of the pause interval corresponding to this contraction depend on the driving frequency applied just prior to this pause. The amplitude increases whereas the duration of the appropriate interval shortens when the driving frequency is increased. Both parameters are also influenced by the age of the tested animals; they increase from the 6th to the 15th week of life if the driving frequency is low. The effects are explained by the assumption that the circulation of the activator calcium is transferred from extracellular more to intracellular storage sites during maturation of the myocardium.

Aging↗
PubMed1984

Arteriovenous anastomoses at the carotid bodies of rats.

In 2 out of 390 carotid bodies of rats arteriovenous anastomoses (AVA) have been found. Both cases belonged to a group of 12 glomera carotici which were prepared using the semithin section technique. The AVA were found in the course of branches of the glomic arteries leaving the main vessel before its entrance into the carotid body tissue. Thus the AVA were placed near but outside of the carotid bodies. Histologically they showed a distinct extension of the tunica media caused by epitheloidly modified smooth muscle cells. Functionally these AVA could act as shunt vessels (Sperrarterien) that would be able to control the blood flow and/or flow distribution through their carotid bodies.

Animals↗
PubMed1984

[Synthesis of N alpha-(tosyl-beta-alanyl)- and N alpha-(tosyl-epsilon-aminocapronyl)amidinophenylalanineamides as strongly effective inhibitors of thrombin].

The headline compounds were prepared for further determination of structure-activity-relationships. By conversion of cyanophenylalanines with the acidic chloride of tosyl-beta-alanine resp. tosyl-epsilon-aminocapronic acid and aminolysis of the following prepared p-nitrophenylic esters the cyano compounds would get the desired structure, which were converted over the thioamides and thioimidic esters in the amidines by the common way. At the preparation of epsilon-aminocapronic acid derivatives occurred difficulties because of simultaneous formation of the N-tosyl-epsilon-caprolactame. The preparation of corresponding aminobutyric acid derivatives wasn't possible. The prolongation of the C-chain of the branchless amino acid decreased the antithrombine effect.

Aminocaproates↗
PubMed1984

[Successful transvenous electric ablation of the AV conduction system in therapy-refractory atrial flutter].

The technique of closed-chest ablation of the atrioventricular (AV) conduction system was used in 3 patients (53-62 years of age) with atrial flutter not responding to medical management. A persistent third-degree AV block was induced in all patients. Moderate increases in CK and CKMB enzymes but not in Tc-pyrophosphate uptake were observed in these patients. 5 days after the procedure a permanent pacemaker was implanted in each case. We conclude that closed-chest ablation of the AV conduction system is a safe and efficient procedure in selected patients with drug-resistant supraventricular arrhythmias.

Adult↗
PubMed1984

Influence of age on carotid body size and arterial chemoreceptor reflex effects in spontaneously hypertensive (SHR) and normotensive rats.

In normotensive Wistar rats of a random-bred strain and in spontaneously hypertensive rats (SHR) of the Okamoto-Aoki-strain, the mean systemic arterial blood pressure, the pO2, pCO2, pH-values and the base excess of the arterial blood were measured during ventilating normal air as well as hypoxic (12.6% O2 in N2) and hyperoxic (100% O2) gas mixtures. The animals were anaesthetized and breathed spontaneously; they aged 5-6, 15-20, 30-40, and 50-70 weeks. The volume of their carotid bodies was determined morphometrically. When compared with the age-matched normotensive controls at an age of 5-6 weeks the SHR already exhibited slightly but significantly elevated blood pressures but had equal carotid body size and arterial carbon dioxide tension. In contrast, hypertensive animals in the established phase of hypertension (older than 15 weeks) showed greater carotid bodies and a highly significant respiratory alkalosis when compared with the corresponding age-group of the normotensive rats. The reactions of the mean systemic arterial blood pressure and the arterial pCO2 provoked by hypoxia and hyperoxia proved to be age-dependent in both the normotensive and hypertensive animals but this influence of age was different in the two strains of rats. The data support the concept that alterations of arterial chemoreceptor structures and reflex effects found in the established phase of hypertension are the result of this disease. Furthermore they indicate that, when interpreting arterial chemoreceptor reflex effects in hypertensive humans and animals, the stage of hypertension must be taken into account.

Aging↗