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Biomedical subjects

F Hernandez

Publications and source records attributed to F Hernandez.

At least 55 records · Page 3Linked to original sources
PubMed1993

Immunoelectron microscopy of parainfluenza virion glycoproteins with polyclonal and monoclonal antibodies: movement of glycoprotein with monoclonal antibody.

Two glycoproteins (HN and F) of parainfluenza virus were immunogold-labeled with polyclonal and monoclonal antibodies, respectively, and their labeling patterns were compared. Both glycoproteins HN and F were efficiently and homogeneously labeled with polyclonal antibodies, whereas they were labeled much less and heterogeneously with monoclonal antibodies. When either protein was initially labeled with monoclonal antibody, and then the other one, with polyclonal antibody, immunolabels of two glycoproteins were almost completely segregated. Although this segregation deformed virion morphology, it supported the concept of monoclonal antibody-mediated movements of glycoproteins.

Animals↗
PubMed1992

New Granada Medium for detection and identification of group B streptococci.

A methotrexate-containing medium for the detection of beta-hemolytic group B streptococci from clinical specimens on the basis of detection of pigment is described. The medium contained peptone, starch, serum, MgSO4, glucose, pyruvate, methotrexate (as pigment enhancer), phosphate-morpholine-propanesulfonic acid buffer, and selective agents. The recovery of beta-hemolytic group B streptococci was comparable to that obtained with selective broth.

Bacteriological Techniques↗
PubMed1992

Multivariate prediction of in-hospital mortality associated with coronary artery bypass graft surgery. Northern New England Cardiovascular Disease Study Group.

BACKGROUND: A prospective regional study was conducted to identify factors associated with in-hospital mortality among patients undergoing isolated coronary artery bypass graft surgery (CABG). A prediction rule was developed and validated based on the data collected. METHODS AND RESULTS: Data from 3,055 patients were collected from five clinical centers between July 1, 1987, and April 15, 1989. Logistic regression analysis was used to predict the risk of in-hospital mortality. A prediction rule was developed on a training set of data and validated on an independent test set. The metric used to assess the performance of the prediction rule was the area under the relative operating characteristic (ROC) curve. Variables used to construct the regression model of in-hospital mortality included age, sex, body surface area, presence of comorbid disease, history of CABG, left ventricular end-diastolic pressure, ejection fraction score, and priority of surgery. The model significantly predicted the occurrence of in-hospital mortality. The area under the ROC curve obtained from the training set of data was 0.74 (perfect, 1.0). The prediction rule performed well when used on a test set of data (area, 0.76). The correlation between observed and expected numbers of deaths was 0.99. CONCLUSIONS: The prediction rule described in this report was developed using regional data, uses only eight variables, has good performance characteristics, and is easily available to clinicians with access to a microcomputer or programmable calculator. This validated multivariate prediction rule would be useful both to calculate the risk of mortality for an individual patient and to contrast observed and expected mortality rates for an institution or a particular clinician.

Aged↗
PubMed1991

A regional prospective study of in-hospital mortality associated with coronary artery bypass grafting. The Northern New England Cardiovascular Disease Study Group.

OBJECTIVE: A prospective regional study was conducted to determine if the observed differences in in-hospital mortality rates associated with coronary artery bypass grafting (CABG) are solely the result of differences in patient case mix. DESIGN-Regional prospective cohort study. Data including patient demographic and historical data, body surface area, cardiac catheterization results, priority of surgery, comorbidity, and status at hospital discharge were collected. This study presents data for 3055 CABG patients between July 1, 1987, and April 15, 1989. SETTING: This study includes data from all surgeons performing cardiothoracic surgery in Maine, New Hampshire, and Vermont; the data were collected from five regional medical centers. PATIENTS: Data were collected from all consecutive isolated CABG surgery patients during the study period. MAIN OUTCOME MEASURES: Crude and adjusted in-hospital mortality rates associated with CABG. MAIN RESULTS: The overall crude in-hospital mortality rate for isolated CABG was 4.3%. The rate varied among centers (range, 3.1% to 6.3%) and among surgeons (range, 1.9% to 9.2%). Predictors of in-hospital mortality included increased age, female gender, small body surface area, greater comorbidity, reoperation, poorer cardiac function as indicated by a lower ejection fraction, increased left ventricular end diastolic pressure and emergent or urgent surgery. After adjusting for the effects of potentially confounding variables, substantial and statistically significant variability was observed among medical centers (P = .021) and among surgeons (P = .025). CONCLUSION: We conclude that the observed differences in in-hospital mortality rates among institutions and among surgeons in northern New England are not solely the result of differences in case mix as described by these variables and may reflect differences in currently unknown aspects of patient care. Understanding this variation requires a detailed understanding of the processes of care.

Adult↗
PubMed1991

Cerebral sparganosis caused by Spirometra mansonoides. Case report.

Cerebral sparganosis is an uncommon parasitic zoonosis caused by the migrating larva of the genus Spirometra mansonoides. The clinical and computerized tomography presentation, as well as the operative and histopathological findings, of the first known case in Mexico are detailed. The dead larva elicited intense acute inflammation resulting in focal encephalitis. Surgical removal of the larva yielded excellent results.

Adult↗
PubMed1991

Pentamer arrangements in fragments of human rotavirus inner capsids observed by low dose electron microscopy.

Fragments of disrupted capsids were frequently seen in purified preparations of human rotavirus inner capsids by negative staining method in electron microscopy. The ultrastructures of these fragments were analyzed in comparison with the T = 13L model. Well-resolved pentamers were rarely seen in the fragments on observation at the standard electron doses, but were frequently seen at low electron doses, which meant a better preservation of the steric structure of capsid fragments in the latter case. Thus advantages of low dose electron microscopy have been shown in observation of capsid fragments.

Capsid↗
PubMed1990

The finest ultrastructural details of the inner layer of rotavirus revealed by minimal electron doses.

The inner layer of human and calf rotavirus ultrastructure was analyzed using minimal doses in transmission electron microscopy. The morphological unit of spontaneously disrupted virions has the aspect of a flower-like structure, and its petals are hexagonally arranged and have a central pin hole. The similar flower appearance can be observed in complete virions and in rotavirus tube structures produced in aged samples of rotavirus kept for more than a year.

Animals↗
PubMed1989

Ultrastructural study of the endocrine cells of the gut of Testudo graeca (Chelonia).

The digestive tract of Testudo graeca (Chelonia) was investigated by means of electron microscopy using both conventional and immunocytochemical techniques. EC-, L-, D-, G-, B-, N- and EC-L-cells were detected. These cells share several common ultrastructural characteristics with the endocrine cells of mammals (i.e. clear cytoplasm, prominent Golgi apparatus, secretory granules etc.). EC and D1 cells have so far not been described in the esophagus of any animal species; in the present study these cells have been observed in the esophagus of T. graeca. Of special interest was the presence of B-cells in the intestine, suggesting that the migration of B-cells from the gut to the pancreas to constitute pancreatic islets is not concluded in T. graeca. The present study demonstrates that the gut endocrine system of T. graeca is a complex structure containing a large variety of endocrine cell types similar in morphology to those found in higher vertebrates.

Animals↗
PubMed1989

Distribution of mucins in the mucosa of the digestive tract of reptiles: a histochemical study.

In the present study, the distribution and characteristics of mucins in the digestive tract of 3 reptiles (Lacerta lepida, Mauremys caspica and Testudo graeca) are investigated. In the esophagus of Testudo graeca, both the glands and the mucous cells of the surface epithelium contained sulphosialo-mucins. In Lacerta lepida, esophageal mucous cells contained either-sialo-mucins or sulphosialo-mucins. The esophageal mucous cells of Mauremys caspica contained acidic mucosubstances. The stomach of the species studied revealed a small amount of acidic mucosubstances; in Lacerta lepida and Testudo graeca, abundant neutral mucins were detected. In the intestine, the amount of acidic mucosubstances was increased in a caudal direction, the sulphosialo-mucins being predominant. In conclusion, acid mucins were more abundant in the esophagus and intestine than in the stomach. This may be related to cytoprotective roles in the esophagus and protection against potential pathogens in the intestine.

Animals↗
PubMed1989

Ventricular vulnerability in diabetes and myocardial norepinephrine release.

Previously the authors have observed a reduction of the ventricular fibrillation threshold (VFT) in a mild diabetic model. This investigation examines the role of more severe hyperglycemia in altering the ventricular fibrillation threshold and how the sympathetic nervous system modulates the response. Alloxan diabetes was induced in eight male mongrel dogs 3-5 years of age (Group 2), for comparison with matched controls (Group 1). Hemoglobin A1c rose from 2.9 +/- .4-7.8 +/- .3% and body weight was maintained with daily insulin. After 1 year, anesthesia was induced with chloralose and an electrode catheter placed at the right ventricular apex. VFT was 41.7 +/- 1.8 ma in Group 1 and 27.8 +/- 2.1 ma in the diabetics of Group 2 (p less than .001). There was significantly greater decline of VFT in response to epinephrine infusion in Group 2. The threshold in diabetics rose to normal levels after infusion of the beta-blocking agent, esmolol. Subsequently, the response of the cardiac sympathetic system was assessed during ventricular pacing at 200 beats/minute. Serial paired blood samples were taken from catheters in the aorta and coronary sinus for catecholamine assay by HPLC. Both groups had similar coronary blood flow responses by the thermal method, as well as changes in arterial pressure. While no change occurred in Group 1, a progressive rise of norepinephrine (NE) concentration was observed in coronary venous effluent of Group 2 (p less than .01). The basal arterial-coronary sinus difference was-123 +/- 52 pg/ml, which rose during pacing in Group 2 to a peak of -376 +/- 9.3 pg/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Is intravenous urography indispensable in evaluating a bladder emptying disorder?].

Two patients with disorders of bladder emptying (dysuria, pollakiuria) were treated by endourethral resection after being investigated by ultrasonography without intravenous pyelography. Intravenous pyelography performed subsequently due to persistence and even deterioration of the bladder emptying disorders revealed the diagnosis and allowed treatment of renal tuberculosis. Intravenous pyelography is therefore an essential part of the assessment of patients with prostatic symptoms.

Aged↗
PubMed1989

[Functional and urodynamic study of cecocystoplasties with or without detubation].

The authors analyse and compare the clinical and urodynamic results of 16 tubed caecocystoplasties and 5 detubed ileocaecocystoplasties. The urodynamic assessments were performed between 2 months and up to 4 years after the operation. After a period of about 6 months, there was a functional difference between these two types of reservoir. The loss of pressure peaks in detubed reservoirs is not sufficient to ensure complete nocturnal continence. Neovesico-sphincteric synergy is responsible for real sphincteric self-re-education. Rationally, a detubing procedure in bladder replacement is only desirable in the case of a "deficient" sphincter.

Cecum↗
PubMed1989

[Extra-corporeal lithotripsy (EDAP LT 01) in urinary lithiasis].

Five hundred and twenty six extracorporeal lithotripsies have been performed for renal and ureteric stones. Using low frequencies (1.25 to 2.5 cycles per second), extracorporeal lithotripsy was performed without anaesthesia and without premedication in 85% of cases. 91.9% of patients treated were followed and reviewed after one and three months: 292 (55%) were successes, 124 (22.5%) obtained partial results, 122 (22.5%) were failures. The best results were obtained in stones less than 20 mm in diameter. The results could only be improved by a second session of extracorporeal lithotripsy. Scintigraphic scars observed after high frequency lithotripsy and not observed after low frequency lithotripsy were again seen after renewal of the firing head.

Evaluation Studies as Topic↗
PubMed1989

Cuticular ultrastructure of Paragonimus from Costa Rica.

The surface ultrastructure of eggs, metacercariae, and adults of Paragonimus endemic to Costa Rica were examined under the scanning electron microscope. Two different morphological types of parasites were found. The most commonly found form was the "first type" (86%) corresponding to the previous descriptions of P. mexicanus. The metacercariae of this type showed an oral sucker surrounded by papillae clustered on the dorsal lip, the ventral sucker showed six internal and from 30 to 35 external papillae. The most evident difference in the "second type" was observed on the ventral sucker, because it showed an intermediate row of five to six papillae located between the internal and external papillae. In conclusion, the Paragonimus species of Costa Rica is P. mexicanus. The morphological differences seen could be a variation of the same species or another species.

Animals↗
PubMed1988

Dual mechanism of phosphatidylinositol hydrolysis by substance P in brain.

The treatment of cerebral cortex slices with substance P caused alterations in the phospholipid levels. A significant loss of phosphatidylinositol in a dose-dependent manner was observed. In contrast, the levels of the major phospholipids, phosphatidylcholine and phosphatidylethanolamine, were enhanced by the peptide. The effect of substance P on the fatty acid composition of phospholipids was also studied. The most relevant event was the decrease in the content of both stearic and arachidonic acids of phosphatidylinositol. This decrease was more evident at the lowest substance P concentration tested (65 pM). These results are consistent with the phosphatidylinositol breakdown caused by substance P in some tissues. Furthermore, our data indicate that this breakdown is selective depending on the peptide dose. Thus, in the presence of very low doses of substance P (65 pM) a preferential degradation of 1-acyl(predominantly stearoyl)-2-arachidonoylglycerophosphoinositol molecular species occurs, whereas high doses of the peptide (0.65 microM) induce a generalized hydrolysis of phosphatidylinositol without showing any preference towards molecular species rich in arachidonic acid. Hence we describe for the first time a dual, dose-dependent mechanism for phosphatidylinositol hydrolysis by substance P, suggesting the possibility that either phospholipase A2 or phospholipase C activation is involved.

Animals↗
PubMed1988

A histochemical study of the mucins in the digestive tract of the chicken.

Little is known about the distribution of glycoproteins in the digestive tube of birds. In the present study, the localization and distribution of mucins in the digestive tract of the chicken are reported. Sialo- and sulpho-mucins were widely distributed throughout the chicken digestive tube. Some of the mucous cells of the proximal segment of the proventriculus presented neutral glycoproteins; in the medial segment, surface cells containing only sialo-mucins were observed. Surface cells of the gizzard contained both sialo- and sulpho-mucins while PAS-positive material was localized in the lumen of the glands. 2 types of mucous cells were observed in the small intestine; 1 type contained only sialo-mucins and the other contained both sialo- and sulpho-mucins. In the large intestine and caecum, both types of acid mucins were present in the mucous cells. In conclusion, the distribution of glycoproteins in the chicken reported in the present study show marked differences with that reported in other avian species.

Animals↗
PubMed1988

Significance of electrocardiographic isolated abnormal terminal P-wave force (left atrial abnormality). An echocardiographic and clinical correlation.

An abnormal terminal negative deflection in precordial lead V1 (PTFV1) is occasionally present as an isolated electrocardiographic finding. To determine the significance of this, 41 patients with PTFV1 greater than or equal to 0.04 mms were recalled for a repeated electrocardiogram as well as an echocardiographic examination. Patients were classified as cardiovascular normal (n = 15) or abnormal (n = 26). Left atrial enlargement was the most common echocardiographic abnormality found, but represented less than a third of the total. P-wave prolongation (greater than 110 ms) was present in 30 of the 41 patients and 21 of the 26 abnormal patients. This persisted into the second study, while the PTFV1 fell significantly in both the normal and abnormal groups. Among the P-wave abnormalities found, combinations were used to identify patients most likely to have cardiovascular disease. The most discriminating was an initial abnormal PTFV1 in combination with P-wave prolongation (sensitivity, 82%; specificity, 40%; positive predictive value, 70%; and negative predictive value, 55%). Maximal specificity (93%) and positive predictive value (88%) were achieved when P-wave prolongation and PTFV1 greater than or equal to 0.06 mms were present in both studies, although the sensitivity for this criterion was only 27%. The isolated P-wave abnormality described may be helpful in suggesting the presence of underlying cardiovascular disease and indicate the need for further evaluation.

Adult↗