123rc/medical_text huggingface dataset:
Left ventricular asynchrony: an indicator of regional myocardial dysfunction. There is a marked heterogeneity of myocardial wall thickening within the left ventricle and among different individuals. It is therefore difficult to detect regional myocardial dysfunction from absolute values of systolic wall thickening. We tested whether the extent of left ventricular asynchrony during ischemia and reperfusion can be used to quantify the severity of regional myocardial dysfunction when nonischemic baseline function is not known. In six anesthetized, open-chest dogs regional myocardial wall thickness was measured by means of sonomicrometry under control conditions, at three degrees of ischemic dysfunction (mild, moderate, and severe), and after release of a 15-minute occlusion of the left circumflex coronary artery, when degrees of moderate and mild reperfusion dysfunction similar to the preceding ischemic dysfunction were present. Two indexes of left ventricular asynchrony were calculated: (1) postejection thickening (PET) and (2) the phase difference of the first Fourier harmonic of posterior versus anterior myocardial wall motion (PD). Systolic myocardial wall thickening was decreased from 15.3 +/- 3.1 (standard deviation) % (control value) to 9.7 +/- 1.4% (mild ischemia), 4.2 +/- 1.6% (moderate ischemia), and -3.7 +/- 3.1% (severe ischemia). Conversely PET increased from 0.02 +/- 0.04 mm (control value) to 0.15 +/- 0.22 mm (mild ischemia), 0.19 +/- 0.15 mm (moderate ischemia), and 0.50 +/- 0.26 mm (severe ischemia). PD increased from 9 +/- 28 degrees (control value) to 22 +/- 19 degrees (mild ischemia), 54 +/- 18 degrees (moderate ischemia), and 107 +/- 21 degrees (severe ischemia). After release of the 15-minute left circumflex coronary artery occlusion, PET and PD recovered to 0.34 +/- 0.19 mm and 36 +/- 24 degrees (moderate dysfunction) and 0.25 +/- 0.31 mm and 29 +/- 8 degrees (mild dysfunction), respectively. There were inverse linear relationships between systolic wall thickening and PET (r = -0.86, p less than 0.001) and between systolic wall thickening and PD (r = -0.87, p less than 0.001). Inotropic stimulation by postextrasystolic potentiation increased regional systolic myocardial posterior and anterior wall thickening but did not alter the extent of left ventricular asynchrony. Thus, when normal baseline function is not known, the severity of regional myocardial dysfunction at a given inotropic state can be determined by analysis of left ventricular asynchrony. There was no significant correlation between the extent of PET and PD during ischemia and at early reperfusion and the recovery of contractile function at late reperfusion. Thus PET does not provide a prospective marker for the functional outcome of reperfusion.
Lung thallium-201 uptake during exercise emission computed tomography. To test whether the analysis of lung uptake is worth adding to the interpretation of exercise thallium-201 (201TI) emission computed tomography (ECT), a lung/heart ratio of 201TI uptake was measured from an anterior image during ECT in 25 clinically normal (Group 1), 91 angiographically normal (Group 2), and 265 subjects with coronary artery disease (Group 3). The mean +2 s.d. of ratios in Groups 1 and 2 were the same (0.37). In Group 3, 80 subjects (30%) with increased ratios (greater than 0.37) had higher frequencies of prior infarction and multi-vessel disease, more severe left ventricular dysfunction, and 201TI defects than 185 subjects with normal ratios. Subjects with markedly increased ratios (greater than 0.45) had three-vessel disease more frequently than those with slightly or moderately increased ratios (67% versus 14% or 35%). Thus the measurement of lung/heart ratios may provide information regarding the severity of coronary artery disease and should be added to the routine interpretation of exercise ECT.
Modulation of neurogenic inflammation by neutral endopeptidase. The enzyme neutral endopeptidase (NEP) is bound to the membranes of selected cells in the airways that have receptors for tachykinins. The location of the enzyme, along with its selectivity of substrates (tachykinins are a preferred substrate), allows the enzyme to cleave tachykinins that come close to the cell-surface receptors. By cleaving and thus inactivating tachykinins released during stimulation of the sensory nerves, NEP limits the degree of neurogenic inflammation. Neutral endopeptidase exists in the basal cells of the airway epithelium, nerves, smooth muscle, glands, blood vessels, and perhaps other cells. Thus, the enzyme modulates smooth muscle contraction, gland secretion, cough, vascular permeability, and neutrophil adhesion. Decreased NEP activity occurs with epithelial removal, during respiratory viral infections, and during exposure to irritants (e.g., cigarette smoke and toluene diisocyanate). Delivery of recombinant NEP (rNEP) by aerosol suppressed cough responses during neurogenic inflammation. We suggest that decreased NEP activity will result in exaggerated neurogenic inflammation and may play an important role in inflammatory diseases in airways. Furthermore, drugs that cause up-regulation of NEP may play a therapeutic role by suppressing neurogenic responses. Replacement therapy with rNEP may be useful in diseases where inflammatory peptides (e.g., tachykinins, bradykinin) play a role in pathogenesis.
Managing geriatric arrhythmias, II: Drug selection and use [published erratum appears in Geriatrics 1991 Jun;46(6):100] Age-related impairments in antiarrhythmic drug distribution, metabolism, and excretion may result in accumulation of these potent drugs, increasing the risk of adverse drug reactions and drug interactions in the elderly. These risks are minimized by using modest initial dosage with slow dosage titration. Therapeutic drug monitoring is a method which employs antiarrhythmic concentration data and a determination of drug clearance in order to develop an optimal dosing regimen. The pharmacology, indications for use, and adverse effects of currently available antiarrhythmics are reviewed. Dosing guidelines for the geriatric population are provided.
The IVH complex of lesions: cerebrovascular injury in the preterm infant. The term intraventricular hemorrhage has become associated with a variety of cerebrovascular insults in preterm infants. Because of a shared pathophysiology and timing, these are the neurologic lesions to search for when evaluating sick preterm infants. This complex of lesions is common and, when parenchymal injury occurs, likely to result in neurologic sequelae. A review of the variety of injuries, their pathophysiology, their diagnosis by cranial ultrasonography, and their prognosis is offered. Emphasis is placed on the need for assessment over time when evaluating parenchymal lesions in preterm infants.
Detection and assessment of unstable angina using myocardial perfusion imaging: comparison between technetium-99m sestamibi SPECT and 12-lead electrocardiogram. Forty-five studies using technetium-99m (Tc-99m) sestamibi single photon emission computed tomography (SPECT) were performed on patients hospitalized for spontaneous chest pain suggestive of myocardial ischemia. The studies were done after an injection during an episode of chest pain and a repeated injection when the patients were free of pain. All patients were hospitalized with a presumed diagnosis of unstable angina, and none had evidence of a previous myocardial infarction. The presence of a perfusion defect observed with Tc-99m sestamibi injected during chest pain had a 96% sensitivity and a 79% specificity for the detection of significant coronary artery disease (stenosis greater than or equal to 50%) on subsequent angiography. When the criterion of a larger perfusion defect during pain compared to absence of pain was used, the sensitivity was 81% and the specificity was 84%. In contrast, transient electrocardiographic ischemic changes during pain had a sensitivity of 35% and a specificity of 68%; electrocardiographic changes during or outside episodes of chest pain had a sensitivity of 65% and a specificity of 63% for the diagnosis. Tc-99m sestamibi SPECT represents a reliable noninvasive diagnostic tool that could aid in the diagnosis of myocardial ischemia in patients with spontaneous chest pain and provide additional information to that provided by the electrocardiogram.
Anatomic, metabolic, neuropsychological, and molecular genetic studies of three pairs of identical twins discordant for dementia of the Alzheimer's type. Three pairs of twins, each with proved monozygosity, were shown to be discordant for dementia of the Alzheimer's type and to have remained discordant for periods of 8 to 11 years. Dementia of the Alzheimer's type was demonstrated by history; serial clinical examinations; serial measurements of cerebral glucose utilization using positron emission tomography and of cerebral ventricular volumes and of rates of change of volumes using quantitative computed tomography; and by serial neuropsychological tests. The results of each of these measures showed no evidence of clinical abnormality in any unaffected twin. DNA markers from the proximal long arm of chromosome 21 did not distinguish between the affected and the unaffected member of any pair of identical twins. Family pedigrees were negative for Alzheimer's disease. The results suggest that environmental or other nongenetic factors contribute to Alzheimer's disease in discordant monozygotic twins, or that some cases arise by a postzygotic somatic mutation.
A giant renal artery aneurysm diagnosed post partum. We report a case of a 5.8 cm. right renal artery aneurysm diagnosed intact 8 weeks post partum. Rupture of a renal arterial aneurysm during pregnancy is a rare but well described catastrophic event. There are no previous reports of an intact renal artery aneurysm diagnosed either ante partum or post partum. To our knowledge, this also represents the largest reported renal artery aneurysm. The aneurysm was repaired successfully with kidney salvage and closure of the fistulous connection to the renal vein.
Rat soleus muscle ultrastructure after hindlimb suspension. The aim of the present investigation was to determine, by quantitative electron microscopy, the effects of a 5-wk tail-suspension period on rat soleus muscle ultrastructure. A marked decline (-60%) in muscle mass occurred. The mean fiber cross-sectional area decreased to a greater extent (-75%) than the capillary-to-fiber ratio (-37%), leading to a higher capillary density (+148%) after hypokinesia. The total mitochondrial volume density remained unchanged, whereas the volume density of myofibrils was slightly but significantly reduced (-6%). A shift from subsarcolemmal to interfibrillar mitochondria occurred. Interfibrillar mitochondrial volume density was highest near the fiber border and decreased toward the fiber center. An increase in volume density of satellite cells suggested muscle regenerative events. Soleus atrophy with tail suspension greatly decreases the muscular volume but leaves the ultrastructural composition of muscle fibers relatively unaffected.
Murine mast cells synthesize basement membrane components. A potential role in early fibrosis. Mast cells are resident in tissues, particularly in association with endothelial and epithelial cell basement membranes, and increase at sites of inflammation, injury, and fibrosis. Although mast cells are known to both release and generate proinflammatory molecules in response to inflammatory stimuli, little is known about their normal biologic function. Here we demonstrate that IL-3-dependent mouse PT18 mast cells, mouse bone marrow-derived mast cells, and rat basophilic leukemia cells express large amounts of mRNA for collagen IV, laminin, and heparan sulfate proteoglycan. Western blot analysis confirmed that mast cells synthesize and secrete significant amounts collagen IV and laminin B1 and B2 chains. These data suggest that mast cells may contribute to normal tissue repair and/or the early overproduction of basement membrane components seen in a variety of fibrotic conditions.
Gunshot wounds to the cervical spine. A retrospective review was performed on 28 patients with low-velocity gunshot wounds to the cervical spine. These composed 31% of all spinal gunshot wounds seen during the study period between 1979 and 1988. Surgical decompression did not seem to improve neurologic recovery in either the incomplete or complete patients. Neurologic recovery also appeared to be unaffected by the presence of retained intracanal bullet fragments. The authors found no advantage to routine neck exploration of this penetrating injury. Complications were seen in 93% of the patients. Most complications were thromboembolic, pulmonary, and urinary tract infections. No cases of instability occurred as a direct result of the gunshot wound. No deaths occurred in this series. Two cases of posttraumatic syrinxes were diagnosed. The authors' current treatment recommendations for these patients include selective wound management and observation of retained intracanal bullet fragments in patients with complete lesions. Surgical decompression after this injury is not recommended.
Balloon valvuloplasty for fungal endocarditis induced stenosis of a bioprosthetic tricuspid valve. Palliative treatment was provided without complications by double balloon valvuloplasty of a stenotic porcine tricuspid valve in a patient with fungal endocarditis. With two 15 mm diameter valvulotomy balloons the peak tricuspid gradient decreased from 21 to 7 mm Hg and valve area increased from 0.3 to 1.2 cm2. After the procedure the patient clinically improved; however, valve replacement was not performed as planned because the patient developed an intracranial hemorrhage. She subsequently died of complications of fungemia. The present report demonstrates the possible use of valvuloplasty as a palliative procedure in selected patients with valvular stenosis involved with endocarditis.
A new syndrome: hearing loss and familial salivary gland insensitivity to aldosterone in two brothers. Two male siblings presented in infancy with hyponatremia. The levels of plasma renin activity and aldosterone were elevated. Sodium supplement was necessary to maintain normal sodium balance. The salivary sodium concentrations were markedly elevated, with sweat sodium levels being in the upper normal range. Urinary sodium concentration and renal epithelial exchange between sodium and potassium were normal. This was felt to be due to an autosomal recessive disorder. Both siblings were later diagnosed as having a bilateral moderate to severe sensorineural hearing loss with intermittent conductive overlay due to middle ear fluid. The sensorineural loss was also felt to be autosomal recessive in origin, but the possibility of a disturbance of sodium balance in the inner ear has been questioned.
Identification, prevention, and treatment of silicone oil pupillary block after an inferior iridectomy. We treated two patients in whom silicone oil pupillary block developed despite a patent inferior iridectomy. The clinical characteristics of this complication were a deep anterior chamber, specular reflexes from the iris surface, identification by biomicroscopy of aqueous trapped inferiorly in the vitreous cavity, and no convection currents in the anterior chamber. This complication may be prevented by early face-down positioning of the patient after the operation, and the avoidance of large, centrally located, inferior iridectomies. We recommend that the iridectomy be placed peripherally no larger than 2 mm and propose a new technique for breaking the silicone oil block, which was clearly successful in one of the patients.
Loss of nocturnal decline of blood pressure in hypertension due to chronic renal failure. The aim of this study was to assess the blood pressure profile of chronic renal failure in comparison with essential hypertension. Thirty hypertensive patients with chronic renal failure due to non-vascular nephropathies were matched by age, sex, and mean 24 h blood pressure, with 30 patients affected by uncomplicated mild-to-moderate essential hypertension. They were studied in an open hospital ward. Diet, meal times, sleep times, and activity schedules were standardized. Noninvasive, automatic, blood pressure recordings were performed for 48 h at sampling intervals of 15 min. The mean 24 h blood pressure almost coincided in the two groups. However, in essential hypertension a mean (+/- SD) nocturnal fall of systolic and diastolic blood pressure was found (12.7 +/- 3.8 and 12.9 +/- 4.8 mm Hg, respectively), while renal patients displayed an average nocturnal increase of 2.7 +/- 8.9 mm Hg and 3.7 +/- 7.8 (P less than .001). The renal patients had also higher heart rates, with a significantly blunted nocturnal fall (4.4 +/- 4.5 beats/min as compared to 9.3 +/- 3.1 beats/min of essential hypertension; P less than .001). Among the renal patients, the day-night blood pressure changes showed no significant correlation with age, creatinine clearance, hematocrit, nocturnal change in heart rate, or day or night mean blood pressure levels. These data suggest that an abnormal day-night pattern of blood pressure is present in chronic renal failure patients independently from external interfering factors. Hence, casual measurements of blood pressure confined to daytime may underestimate a hypertensive condition associated with chronic renal failure.
A report on radiation-induced gliomas. Radiation-induced gliomas are uncommon, with only 73 cases on record to date. The disease that most frequently occasioned radiation therapy has been acute lymphoblastic leukemia (ALL). Three more cases are added here, two after irradiation for ALL and one after irradiation for tinea capitis. In a review of the relevant literature, the authors stress the possibility that the ALL-glioma and the retinoblastoma-glioma links point to syndromes in their own right that may occur without radiation therapy.
Buschke-Loewenstein tumor: verrucous carcinoma of the penis. The Buschke-Loewenstein tumor is an anogenital tumor of characteristic clinical and histologic pattern best considered as a low-grade, well-differentiated squamous cell carcinoma. This remarkable neoplasm and its features are reviewed in detail, stressing salient advances in our understanding of it.
Cytostatic and cytotoxic effects of recombinant tumor necrosis factor-alpha on sensitive human melanoma cells in vitro may result in selection of cells with enhanced markers of malignancy. Monolayer cultures of the human melanoma cell lines StML-12, StML-11, StML-14 (third, respectively, twenty-fifth subculture), and SKMel-28 derived from specimens representing different stages of tumor progression were treated with 10-10,000 U/ml rTNF-alpha applied for 72 h. The effects of rTNF-alpha on cell proliferation, DNA synthesis, cell viability, cloning efficiency, cell division, cell morphology, and the immunophenotype were studied in triplicate experiments. The cell line StML-14(3) revealed a significantly dose-dependent reduction of growth due to both cytostatic and cytotoxic activities of rTNF-alpha as well as a decrease of CE. Increased numbers of cells in prophase were observed 24 h after addition of r-TNF-alpha. In addition, dislocation of chromosomes in the metaphase, formation of micronuclei, and dose-dependent increases of cells exhibiting micronuclei and the DNA amount per cell were detected at the end of treatment. On the other hand, only a slight sensitivity to the anti-proliferative effect of rTNF-alpha was observed with StML-14(25) and SKMel-28, whereas StML-12 and StML-11 were significantly resistant. The last four cell lines were serially subcultivated and presented common phenotypic patterns with more malignant characteristics than the cell line StML-14(3) before treatment. Overall, rTNF-alpha enhanced the malignant immunophenotype of the cell lines tested. It increased the expression of the "late" melanoma progression markers A.10.33 and A.1.43, and Ki67, and it decreased the expression of the "early" progression marker K.1.2. The expression of HLA-I, HLA-DR, and ICAM-1 was also enhanced after rTNF-alpha treatment, whereas in contrast to other cytokines, rTNF-alpha did not induce the de novo expression of HLA-DR in HLA-DR-negative melanoma cell lines. These findings indicate that rTNF-alpha induces cytostasis and decreases cell viability of certain rTNF-alpha-sensitive melanoma cells. These effects may result in selection of rTNF-alpha-non-sensitive human melanoma cell populations with higher proliferation rates and a more aggressive immunophenotype in vitro.
Neurodevelopmental performance of very-low-birth-weight infants with mild periventricular, intraventricular hemorrhage. Outcome at 5 to 6 years of age. The neurodevelopmental outcome of 38 very-low-birth-weight neonates (birth weight, less than 1501 g) was followed up prospectively from birth to 5 to 6 years of age to assess the neurodevelopmental sequelae of mild periventricular, intraventricular hemorrhage (grades I and II). All neonates were screened for periventricular, intraventricular hemorrhage at 5 to 10 days of age. Eleven incurred a mild periventricular, intraventricular hemorrhage (group 1) and 27 had no periventricular, intraventricular hemorrhage (group 2). Each of the infants was neurodevelopmentally normal at 1 to 2 years of age. The 38 children were matched by race, age, sex, and socioeconomic status with control children (group 3) who had been born at term. On outcome measurements at 5 to 6 years of age, groups 1 and 2 scored significantly lower than group 3 on the combined test measurements and on three of the four individual measurements. Group 1 scored significantly lower than group 2 on the combined test measurements only. These data indicate that very-low-birth-weight infants are at risk for learning problems. Although children with mild periventricular, intraventricular hemorrhage did not demonstrate a significant deficit on individual test scores, the significant difference on the combined battery suggests that mild periventricular, intraventricular hemorrhage has an adverse effect on global performance.
Methotrexate therapy for persistent ectopic pregnancy after conservative laparoscopic management. Persistent ectopic pregnancy is a recognized complication of conservative laparoscopic surgery. Three such cases were treated successfully with methotrexate and citrovorum factor rescue. All three patients experienced mild lower abdominal pain for a maximum of 36 hours; no other adverse effects were noted. More experience with this therapy will be necessary before subsequent fertility rates can be determined.
Microinvasive carcinoma of the uterine cervix (International Federation of Gynecology and Obstetrics Stage IA). In 1985 the International Federation of Gynecology and Obstetrics (FIGO) subdivided Stage IA cervical cancer and specified metric criteria to demarcate Stage IA from Stage IB. Early stromal invasion (Stage IA1) denotes the first invasive protrusions of a carcinoma in situ into the stroma. Microcarcinomas (Stage IA2) are small cancers a number of orders of magnitude larger than Stage IA1 lesions and with a maximum depth of invasion of 5 mm and a maximum horizontal spread of 7 mm; larger lesions are classified as Stage IB. This study reviews 486 patients previously classified as having Stage IA disease. This yielded 344 Stage IA1 and 101 Stage IA2 lesions; 41 cancers were reclassified as Stage IB. Three hundred nine, 89, and 38 patients were followed for greater than or equal to 5 years. One (0.3%) patient with Stage IA1 disease re-presented with Stage IIB disease 12 years after conization. Five (5.6%) patients with Stage IA2 lesions developed invasive recurrences; three died. None of the 38 patients reclassified as having a Stage IB lesion, including 16 who were treated conservatively, developed a recurrence. The FIGO classification is not a guideline for treatment. Stage IA1 lesions can be treated conservatively, but treatment in Stage IA2 must be individualized. Risk factors such as vascular space involvement and confluency are of high sensitivity but low specificity.