PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Precipitating Factors”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1998

Retrograde multiple and multifiber accessory pathway conduction in the Wolff-Parkinson-White syndrome: potential precipitating factor of atrial fibrillation.

INTRODUCTION: The determinants of susceptibility to atrial fibrillation (AF) and the existence of accessory pathway conduction have remained unidentified in the Wolff-Parkinson-White (WPW) syndrome. We tested the hypothesis that excitation inputs into the atrium over a retrograde multiple or multifiber accessory pathway during AV reentrant tachycardia (AVRT) could precipitate initiation of AF. METHODS AND RESULTS: Two hundred fifty consecutive patients with WPW syndrome underwent electrophysiologic study and radiofrequency catheter ablation. The patients were classified into two groups according to the study results: 29 with retrograde multiple or multifiber accessory pathway (MP) and 221 with retrograde single accessory pathway (SP). Compared with the SP patients, the MP patients showed a significantly higher incidence of clinical AF (MP vs SP: 19/29 vs 51/221, P < 0.01), induced AF (12/29 vs 32/221, P < 0.01), and initiated AF during ventricular pacing and AVRT (10/12 vs 17/32, P < 0.05). There were no differences between the two groups in incidence of clinical and induced AVRT (24/29 vs 200/221 and 25/29 vs 206/221, respectively), mean cycle length of induced AVRT, or electrophysiologic parameters of the accessory pathway. AF inducibility during AVRT or ventricular pacing was eliminated by partial ablation in 7 of 10 patients with MP. After total ablation, the incidence of induced AF was similar between the two groups (MP vs SP: 1/29 vs 11/221). CONCLUSION: The existence of a retrograde multiple or multifiber accessory pathway in patients with WPW syndrome is associated with a higher incidence of clinical and induced AF. Successful ablation of the retrograde multiple or multifiber accessory pathway can eliminate the induction of both AVRT and AF.

Adult↗
PubMed1985

Stress as a precipitating factor in subjects with recurrent herpes labialis.

The model of recurrent herpes labialis was selected to evaluate the role played by stress in increasing susceptibility to illness. Initially, 35 paid volunteers with recurrent herpes were enrolled in the project. Compared with 35 age- and sex-matched controls, this group demonstrated a familial predisposition for recurrent herpes labialis. Eighteen subjects without confounding variables known to precipitate recurrent herpes infections completed a pretested "stress" questionnaire during a dormant and again during an active stage of infection. In the week prior to the appearance of a recurrence, this group experienced increased daily hassles, increased stressful life events, and higher state anxiety. These findings are discussed in the broader context of stress-associated disease with some speculations concerning a possible biologic mechanism, which involves modulations of T-lymphocyte function.

Adult↗
PubMed1981

Dialysis encephalopathy: precipitating factors and improvement in prognosis.

The course of typical dialysis encephalopathy (D.E.) in 12 patients is described. Five patients are still alive from 31 to 57 months after the onset of the disease. Their mental state has improved, but 3 have severe, residual paraplegia. Improvement was associated with the presence of a well functioning renal transplant or dialysis with deionized water. Only one case has developed since deionization of water containing more than 50/micrograms/l of aluminium has been routine. The patients' histories suggest that immobilization, surgery, administration of corticosteroids and hypophosphatemia, all of which induce a negative calcium balance, may release aluminium or another toxic substance from bone and precipitate the onset of D.E.

Alkaline Phosphatase↗
PubMed1995

Family support and other social factors precipitating suicidal ideation.

To examine the effects of family support and demographics on suicidal behavior, 385 subjects completed a demographic questionnaire and a Suicidal Ideation Questionnaire (SIQ). Sixteen percent described themselves as "serious" ideators, while 59% were seen as ideators, numbers consistent with past suicide research. Multiple regression analyses revealed that the type of caregiver a person reported having while growing up accounted for a significant amount of the variance on ideator status. Serious ideators were more common among single parent households. Although many demographic variables were assessed, only the primary caregiver a person had as a child impacted their status as a suicidal ideator. This suggests that suicidal behaviors may occur due to a complex interaction between social factors and childhood care. The influence of living in a single-parent home may contribute to whether or not a person considers suicide.

Adolescent↗
PubMed1992

Prognosis of acute porphyria: occurrence of acute attacks, precipitating factors, and associated diseases.

We evaluated the prognosis of acute porphyria among 206 adult Finnish patients with acute intermittent porphyria (AIP) or variegate porphyria (VP). The series represents all known patients with these porphyrias in Finland. Of the 47 patients who had a total of 117 acute attacks during the period 1967-1989, 6 died during an attack and 21 attacks were associated with paresis; the frequency of severe attacks was significantly smaller than before 1967 (p = 0.00002). Most pareses and deaths occurred because of a delay in diagnosis and inappropriate treatment of porphyria. For those patients who were symptom-free at the time of diagnosis (1365 follow-up years), the risk of the first subsequent attack was significantly smaller than for those who had had an acute attack before the diagnosis of porphyria (1047 follow-up years, p = 0.005). In addition, milder symptoms of porphyria were more common among those who had had previous attacks than among those who had not (p less than 0.00001). In AIP the risk of attacks correlated with the excretion of porphobilinogen in the urine during remission among adults (p = 0.03); a low rate of excretion predicted freedom from acute attacks. A regular use of many precipitating drugs was never associated with symptoms of porphyria. Two percent of the surgical operations and 4% of the pregnancies were associated with acute attacks. Nearly one-third of the women had symptoms of porphyria associated with the menstrual cycle, but these seldom proceeded to an acute attack. Forty-six percent of the women had used sex-hormone preparations regularly; 2 of them (4.5%) experienced associated acute attacks. Patients with AIP or VP showed increased incidences of hepatocellular carcinoma, and probably also chronic renal failure and hypertension.

Acute Disease↗
PubMed1994

Sudden death in the young. Is acute coronary thrombosis the major precipitating factor?

BACKGROUND: Atherosclerotic coronary artery disease, complicated by acute thrombosis, is the usual cause of sudden death in adults. This study addresses the pathology of coronary arteries in sudden death in the young (< or = 35 years old). METHODS AND RESULTS: Among 200 consecutive cases of sudden death in youth in the Veneto region of Italy, 37 (33 men and 4 women, age 18 to 35 years; mean, 29.4 years) showed obstructive atherosclerotic coronary artery disease in the absence of other cardiac pathological conditions and causes of death. No patient had previous angina pectoris or myocardial infarction. Cardiac arrest occurred at rest in 30 subjects and was related to effort in 7. A histological study was carried out on the obstructive coronary plaques. Degree of lumen stenosis and extension of lipid core and intimal fibrocellular hyperplasia facing the lumen were calculated morphometrically. Immunohistochemistry and electron microscopy were used to further characterize the plaque cell population. Single-vessel disease was found in 33 patients and triple-vessel disease in 4, with an overall total of 45 obstructive plaques, 34 of which were located in the proximal left anterior descending coronary artery. At histological study, only 10 plaques from 10 patients showed acute thrombosis (occlusive in 5 and subocclusive in 5); the remaining 35 were uncomplicated. Thirty-one plaques were fibrous in nature, while the other 14 were atheromatous. Compared with the atheromatous lesions, the fibrous plaques were rarely complicated by thrombosis (3% versus 64%; P < .001) and distinctly exhibited a fairly well-preserved tunica media (81% versus 21%; P < .001) as well as a stratum of neointimal fibrocellular hyperplasia (68% versus 7%; P < .001), which on immunohistochemistry and electron microscopy appeared to be proliferating smooth muscle cells. CONCLUSIONS: In our study population, sudden death was precipitated by acute coronary thrombosis in only 27% of patients with obstructive coronary atherosclerotic plaque. Most of the young victims of sudden death with obstructive coronary atherosclerosis showed single-vessel disease that affected the left anterior descending coronary artery and was due to fibrous plaques with neointimal smooth muscle cell hyperplasia and a preserved tunica media in the absence of acute thrombosis.

Acute Disease↗
PubMed1986

Suppression of cellular immunity by head and neck irradiation. Precipitating factors and reparative mechanisms in an experimental model.

A model was developed in C3H mice to investigate the immunosuppressive effects of head and neck irradiation and to explore mechanisms for repair of the defects. Mice receiving 1200 rad (12 Gy) of head and neck irradiation showed significant depression of delayed-type hypersensitivity, peripheral blood lymphocyte counts, spleen cell counts, and spleen cell production of interleukin-2. Treatment with optimal dosages of thymosin alpha 1 (T alpha-1) produced significant increases in all of these values, in some instances to levels higher than in the nonirradiated controls. In identical experiments with mice irradiated to a portal limited to the pelvic region, T alpha-1 induced only partial remission of the abnormalities. The dose response of T alpha-1 with head and neck irradiation showed a relatively limited dose range for immune restoration, a finding that warrants similar determinations in clinical trials with immunomodulating agents. The results suggest a potential clinical usefulness of T alpha-1 and also interleukin-2 in restoring cellular immunity after irradiation for head and neck cancers. The model appears to be useful for investigating immunomodulating agents before they are clinically evaluated as adjuvants with head and neck irradiation regimens.

Animals↗
PubMed1998

Precipitating factors in lymphedema: myths and realities.

BACKGROUND: Lymphedema is an all too common occurrence following breast carcinoma therapy. Despite its prevalence, the predisposing factors to the development of this secondary form of lymphedema remain poorly understood. METHODS: Several studies have addressed these questions and are reviewed here. RESULTS: Treatment factors that appear to predispose to the late, subjective appearance of lymphedema include the extent of axillary surgery and exposure to high dose axillary radiotherapy, particularly when combined with surgical clearance of the axilla. Other pertinent patient factors may include the presence of hypertension and exposure to airline travel. Clinical features unrelated to the risk of lymphedema development include patient age; drug therapy; time interval to presentation, surgery, or radiotherapy to the breast; total dose of radiation; and menopausal status. The potential importance of concomitant venous abnormalities in these patients is worthy of consideration. CONCLUSIONS: Breast carcinoma-related secondary lymphedema is an important subjective and functional problem for affected patients. Additional research into the predisposing factors to this common problem is likely to foster enhanced patient education and to produce more efficacious measures to control this disease.

Breast Neoplasms↗
PubMed1997

Muslin induced granuloma following wrapping of intracranial aneurysms: the role of infection as an additional precipitating factor. Report of two cases and review of the literature.

Two patients who developed what appeared to be a granulomatous reaction following muslin wrapping of unclipped aneurysms are reported. They presented with cranial nerve palsies and at operation were found to have an abscess around the wrapped aneurysms. In one of these two patients Staphylococcus epidemidis was isolated from the pus. This, together with further evidence from reported cases in the literature, would suggest that infection may play an additional role at least in some cases in the onset of a foreign-body granulomatous reaction seen following wrapping of aneurysms.

Brain Abscess↗
PubMed1995

The precipitating factor in coeliac disease.

In recent years, remarkable progress has been made in the elucidation of cereal protein structure and its relation to coeliac toxicity. Gluten proteins of wheat can be classified according to their primary structure into high-, medium- and low-molecular-weight (HMW, MMW, LMW) groups. Each of these groups contains two or three different protein types having partly homologous, partly unique, structural elements: chi- and gamma-type HMW subunits of glutenin (HMW group), omega 5 and omega 1,2-type gliadins (MMW group) and alpha-type gliadins, gamma-type gliadins and LMW subunits of glutenin (LMW group). Numerous proteins from the same type do exist with only a few modifications of the amino-acid sequence. The structure of the HMW and LMW group proteins can be divided into three and five domains, respectively. Most typical for each type and unique for cereals are the glutamine- and proline-rich domains containing repetitive sequences (HMW group: domain B; LMW group: domain I). omega-type gliadins consist almost entirely of repetitive sequences. Rye and barley, closely related to wheat, have protein types homologous to those of wheat. Early investigations showed that wheat gluten and, in particular, the alcohol-soluble gliadin fraction contained the factor toxic for coeliac patients. Equivalent protein fractions of rye, barley and probably oats were also considered to be toxic. The effects of toxic proteins were not destroyed by digestion with pepsin, trypsin and pancreatin. In-vivo (instillation) testing established the toxicity of alpha-type gliadins, and in-vitro (organ culture) testing of gliadin peptides demonstrated that the N-terminal region (domain I) of alpha-type gliadins is involved in activating coeliac disease. The longest sequences common for toxic peptides were found to be -Pro-Ser-Gln-Gln- and -Gln-Gln-Gln-Pro-. Various in-vitro tests and two in-vivo studies on synthetic peptides support the importance of one or both of these sequences. They do not occur in non-toxic food proteins and are characterized by their ability to form a beta-turn conformation. Although these sequences are probably not sufficient for toxicity in themselves, and other amino-acid residues are additionally required, they could serve as the starting point for further investigation.

Adenovirus Infections, Human↗