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Biomedical subjects

J Hernandez

Publications and source records attributed to J Hernandez.

At least 181 records · Page 10Linked to original sources
PubMed1984

Surgery of acquired lobar emphysema in the neonate.

Surgical treatment for pulmonary interstitial emphysema (PIE) has been reported with increasing frequency. We have done pulmonary lobectomies in 14 neonates with the localized form of PIE. This type of treatment was successful in 11 patients. Two patients expired in the hospital and one showed no improvement. Another six very compromised patients with diffuse PIE were treated during the same period with multiple visceral pleurotomies. Only one survived. Infants with diffuse PIE are usually poor surgical candidates, while those with acquired lobar emphysema (ALE) have been treated successfully with lobectomies.

Female↗
PubMed1983

[Diagnosis and evaluation of the extent of cancer of the prostate].

Diagnosis is suggested by the functional symptoms and digital rectal examination and must be confirmed by histological examination. The second step is to evaluate the patient's condition, the extent of the cancer and the consequences on the urinary system; the choice of the treatment depends on this evaluation. The most common tumors are adenocarcinomas with a histological grading strongly correlated to the lymphatic involvement and frequency of metastases. Lymphatic involvement is closely related to the local clinically demonstrable involvement, histological grade, serum acid phosphatase concentrations and results of lymphography. Upon diagnosis of cancer of the prostate more than half the patients already harbour metastases, usually of the bone. This percentage is correlated to the size of the primary tumor, involvement of the seminal vesicles, histological grade and lymphatic involvement. The authors propose a series of investigations adapted to each case.

Adenocarcinoma↗
PubMed1983

Studies on the fate of labelled palmitic acid in rat lung.

1. Pulmonary palmitic acid metabolism was studied in rats in basal conditions and after experimental talcosis. 2. Palmitic acid was rapidly incorporated into phospholipids and stored in the form of esterified cholesterol. 3. During the experiment a de novo synthesis of triglycerides was not detected.

Animals↗
PubMed1982

Withdrawal of beta-blocking drugs.

Our early observations indicated that when treatment was changed from propranolol to placebo, anginal patients experienced a higher incidence of chest pain during the first week of placebo treatment compared to the second week. Since then, there have been several reports of myocardial infarction and sudden death occurring when propranolol therapy has been stopped. However, more formal hospital studies have indicated that ischemia from propranolol withdrawal is relatively infrequent. Studies in normal subjects and hypertensive patients have shown an increase in beta-receptor sensitivity as suggested by increased responsiveness to isoprenaline after propranolol withdrawal. Some investigators have found an increase in free triiodothyronine levels. Catecholamine levels do not appear to be raised. Other relevant factors in ischemic patients might be a reversal of the favorable rightward shift of the oxyhemoglobin dissociation curve or a reversal of reduced platelet aggregation produced by propranolol. Last, propranolol withdrawal in patients who have received the drug for a considerable period might unmask a withdrawal in patients who have received the drug for a considerable period might unmask a progression of the disease process, so that in the absence of beta blockade oxygen supply is inadequate to meet the requirements of relatively ischemic areas even at rest. Whether all beta blockers are similar to propranolol in this regard is unknown. We are examining, in normal volunteers, the sensitivity of the beta receptor after the withdrawal of atenolol, pindolol, or propranolol, administered for at least 2 weeks after final dose adjustment to levels sufficient to produce maximum inhibition of exercise tachycardia. The sensitivity of the beta receptor is being assessed by the response of bolus injections of isoprenaline and the response to exercise tachycardia.

Adrenergic beta-Antagonists↗
PubMed1982

Alterations in pulmonary function following pneumonectomy for bronchogenic carcinoma.

Twenty-one patients who underwent pneumonectomy for bronchogenic carcinoma at the Nashville Veterans Administration Hospital from November, 1977, to March, 1980, were evaluated with standard pulmonary function tests preoperatively and postoperatively. Twelve patients had Stage I disease, 4 patients had Stage II, and 5 patients had Stage III disease. The interval between the operative procedure and postoperative testing ranged from 2 to 33 months (mean, 12.4 months). Mean functional loss of pulmonary capacity after pneumonectomy was based on analysis of preoperative and postoperative forced vital capacity (FVC) and initial-second forced expiratory volume (FEV1) indices. The mean functional loss as expressed by FVC was 41.5% after right pneumonectomy and 34.0% after left pneumonectomy. The mean functional loss as expressed by FEV1 was 40.2% after right pneumonectomy and 38.3% after left pneumonectomy. The postoperative functional status of each patient was classified according to the New York Heart Association criteria. Nineteen of the 21 patients were in Class I or II preoperatively. Postoperatively, 10 patients were in Class I or II and 11 in Class III or IV. The results indicate that a postoperative FVC less than 2.5 liters and FEV1 less than 1.5 liters are not compatible with active life.

Carcinoma, Bronchogenic↗
PubMed1982

Postjunctional selectivity of alpha-blockade with prazosin, trimazosin, and UK-33,274 in man.

The effects of 3 quinazoline alpha-adrenoreceptor antagonists, prazosin, trimazosin, and UK-33,274, on lying blood pressure (BP), BP response to 60 degrees tilt, pressor response to noradrenaline, phenylephrine, and exercise (isometric and dynamic) were measured in a double-blind study in 6 volunteers. There was no difference between the effects of prazosin 2 mg, trimazosin 200 mg, and UK-33,274 4 mg on lying and tilted BP or on BP response to exercise. All three drugs competitively antagonised the systolic and diastolic pressor effect of phenylephrine and the systolic pressor effect of noradrenaline. Prazosin and UK 33,274 completely suppressed the diastolic pressor effect of noradrenaline and produced an increase rather than a decrease in heart rate (HR). Trimazosin produced a parallel shift in noradrenaline dose response curves for diastolic pressure ahd HR. Prazosin and UK-33,274, but not trimazosin, therefore, produced effects unlike those previously described with alpha-blockers, e.g., phentolamine. The difference between antagonism of the systolic and diastolic effects suggests that the resistance component of the noradrenaline pressor effect, mediated principally via alpha 1-stimulation, is more effectively blocked than the cardiac component, which depends on venous return and alpha 2-mediated venoconstriction. Prazosin and UK-33,274 are clearly alpha 1-selective. Trimazosin is less selective.

Adrenergic alpha-Antagonists↗
PubMed1982

Surgical and medical experience with 734 premature infants with patient ductus arteriosus.

During the past 5 years, patent ductus arteriosus (PDA) presented in 734 preterm infants (less than 2.5 kg and 37 weeks gestation) of 2,532 admissions (29%). The ductus presented with murmur, bounding pulses, and often congestive heart failure. Medical treatment consisted of the following: fluid restriction, furosemide, respiratory support, and rarely digoxin. The patients who were unresponsive to medical treatment had surgical ligation (306 of 734 or 42%). The patients who had ductal ligation were smaller, i .e., 82% of the surgical patients weighed less than 1.5 kg as compared to 38% of the medical patients. Of those patients weighing less than 1.5 kg, the surgical and medical groups were compared and the following observations made: The incidence of respiratory distress syndrome was greater in the surgical group (86% or 216 of 252 patients versus 69% or 111 of 161 medical patients, p less than 0.001) and the long-term survival was better (89% or 224 of 252 surgical patients versus 77% or 124 of 161 medical patients, p less than 0.005). In addition, the average duration of intubation was shorter in this surgical subgroup (8.9 versus 13.6 days). Significant left atrial enlargement and echocardiographic left atrial/aortic (LA/Ao) ratios of greater than 1.5:1 occurred in 58% or 171 of 290 surgical patients versus 32% or 59 of 190 medical patients (p less than 0.001). During the first 3 years of this study (medical treatment averaged 5 days), the duration of intubation in the surgical patients averaged 15.2 days; by comparison, in the last 2 years of this study (medical treatment averaged 1 to 2 days), the duration of intubation was 6.5 days (p less than 0.001). Necrotizing enterocolitis (NEC) occurred in 11% or 46 of 428 medical patients versus 0.3% (one of 305 patients) in the ligated group postoperatively (p less than 0.001). Late deaths were related to lung disease, central nervous system problems, NEC, and so on. From this study, it was determined that ligation of a significant PDA is associated with (1) zero surgical risk, (2) a reduced incidence of NEC, (3) reduced duration of intubation, especially with early ligation, and (4) improvement in late survival. Thus the surgical approach is our treatment of choice for a refractory PDA.

Age Factors↗
PubMed1982

The longer term efficacy of vasodilators in heart failure.

Studies among a total of about 300 patients with congestive heart failure treated over eight to ten months reveal a distinct and sustained benefit from vasodilator therapy. Increased longevity has not yet been established, but in most circumstances there has been noticeable symptomatic, radiological, and hemodynamic improvement. Unresolved problems continue to center around variability in response, difficulties in objective assessment (invasive and noninvasive) before and during therapy, and selection criteria for patients and drugs. Lesser problems include the construction of effective dosage schedules, deleterious effects after sudden withdrawal, development of tolerance, and side effects.

Arteries↗
PubMed1981

Limited subtotal thyroidectomy for Graves' disease.

Limited subtotal thyroidectomy was performed in 42 of 43 patients with Graves' disease. Twenty of 23 patients (87%) who were followed up for an average of 54 months after operation remained euthyroid. Only one patient (4.3%) had recurrent thyrotoxicosis. There were no deaths and no permanent complications. A coexisting, invasive papillary cancer necessitated total thyroidectomy in one patient, and occult papillary cancers were discovered histologically in three others. This study supports the thesis that postoperative thyroid function depends on the volume of remaining thyroid tissue. While preserving thyroid function, limited subtotal thyroidectomy lowers postoperative complications and induces no increase in recurrent thyrotoxicosis.

Adolescent↗
PubMed1981

Fascial relationship of the thymus: Radiologic-pathologic correlation in neonatal pneumomediastinum.

The radiographic appearance of retrothymic pneumomediastinum is quite specific. The findings include elevation of the thymus away from other mediastinal structures with increased lucency beneath it, visualization of a radiodense line extending from the inferior pole of the thymus to the midportion of the heart, and tenting of the pericardium at the point of attachment of this line. This constellation of findings will aid in the differential diagnosis of medial anterior pneumothorax, pneumopericardium, and intrapulmonary cyst in the infant with air block. The paper details the mediastinal anatomy with special emphasis on a previously undescribed layer of connective tissue that accounts for this specific radiographic appearance.

Fascia↗
PubMed1981

Surgical repair of coarctation of the aorta in infants less than six months of age: including the question of pulmonary artery banding.

High mortality rates (20% to 60%) have been reported in the repair of coarctation of the aorta in infancy. During a 4 year period, 34 infants less than 6 months of age had coarctation repair (two prior to 1976). Eleven were less than 2 weeks of age, nine were 2 weeks to 1 month, eight were 1 to 2 months, and six were 2 to 6 months. Associated lesions were patent ductus arteriosus (PDA) (82%), ventricular septal defect (VSD) (53%), and other intracardiac lesions (35%). Twenty-three patients (67%) had emergency operations; the other procedures were semielective. The indications for operation included congestive cardiac failure (91%), acidosis (32%), hypertension (29%), cardiogenic shock (26%), and cardiac arrest (18%). There was one operative death (2.9%) in a patient with severe pulmonary valve insufficiency and multiple VSDs. There was one late death a 4 months (Taussig-Bing complex). Primary repair was used in 15, patch-graft angioplasty in 19 (left subclavian artery in nine, left common carotid in one, and Dacron or pericardial patch in nine). Two (6%) required reoperation for recurrent coarctation (follow-up 3 to 36 months with a mean of 25.8). Of 15 patients with a large VSD, six had pulmonary artery banding with two deaths (one operative and one late), two had debanding plus VSD repair, and two are awaiting operation. The remaining nine patients did not have banding (no operative or late deaths), four patients required late VSD closure, two VSDs closed spontaneously, two VSDs became smaller, and one patient is awaiting VSD closure. The infrequent need for pulmonary artery banding may be partly due to "physiological banding" seen at Denver's high altitude. The VSD spontaneously closed or became smaller in 44% of nonbanded patients. The low operative mortality can be ascribed to (1) aggressive medical therapy, (2) emergency catheterization and repair, (3) avoidance of hypothermia, and (4) adequate relief of the coarctation.

Aorta↗
PubMed1980

Analysis and detection of B cell neoplasms.

Cells from human B cell lymphomas were analyzed by means of the fluorescence-activated cell sorter (FACS) according to the amount of kappa or lambda immunoglobulins (Ig) on their surface. The crucial requirements for sensitive recognition of small numbers of tumor cells admixed in a normal population are described. Tumor cells were identified as an excess of cells bearing one light chain type ('clonal excess') at discrete levels of fluorescence intensity. Normal patterns of fluorescence staining are compared to those for tissues infiltrated with tumor. For B cell neoplasms with surface Ig of weak intensity, such as chronic lymphocytic leukemia, as few as 1% of the tumor cells admixed with normal cells could be detected; the bright surface fluorescence of cells from lymphoma permitted their recognition when only 0.1% of the tumor cells were present. FACS analysis was carried out on the peripheral blood of a series of patients with B cell lymphoma whose blood was normal by classic cytologic and cytochemical analysis. Nevertheless, circulating tumor cells were recognized in the majority of cases, suggesting that 'subclinical leukemia' is a common finding in B cell lymphomas.

B-Lymphocytes↗
PubMed1979

Effect of storage processes on the bacterial growth-inhibiting activity of human breast milk.

Human breast milk samples were collected from lactating mothers, and aliquots were maintained at room temperature, frozen, and pasteurized. Samples were inoculated with 10 to 50 colony-forming units per milliliter (cfu/ml) of Escherichia coli or group B streptococcus, and incubated at 37 C. Quantitative growth was measured at eight and 24 hours. No inhibitory activity was demonstrated by control broth, commercial formula, and pasteurized breast milk, which had a rapid logarithmic growth to a maximum of 10(8) to 10(9) cfu/ml at 24 hours. Compared with these controls, fresh breast milk, fresh frozen breast milk, and breast milk frozen for 21 days demonstrated a significant inhibition of bacteria growth. A trend toward gradual loss of inhibiting activity was noted with prolonged freezing of breast milk. Although freezing may quantitativly decrease the amount of some breast milk host-defense factors, it cannot be assumed that comparable functional reductions will necessarily result.

Escherichia coli↗
PubMed1979

Spinal injuries in the F/FB-111 crew escape system.

During the years 1970-75, a larger than expected number of aircrewmen, forced to use the F/FB-111 crew escape module, experienced acute spinal trauma during otherwise uneventful ejection. This trend in the incidence and severity of F/FB-111 aircrew spinal injuries attracted considerable attention and stimulated extensive inquiry concerning the ethiology of the trauma in order to implement appropriate corrective measures. In response to the expressed concerns, an investigation was initiated to analyze the biodynamic pathogenetic mechanism associated with ejection in the F/FB-111 crew escape module. The purpose of this retrospective investigation is to identify the frequency and severity of spinal trauma in the F/FB-111 crew escape module and to shed additional light on the patterns and severity along with the orthopaedic biomechanics of spinal injury.

Accidents, Aviation↗