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Biomedical subjects

J Fernandez

Publications and source records attributed to J Fernandez.

At least 109 records · Page 6Linked to original sources
PubMed1994

Lunular hypertrophy and aortic valve disease.

Cuspid malcoaptation secondary to abnormal hypertrophy in combination with stiffening involving the line of apposition (lunular hypertrophy) has not been recognized as a cause of aortic valve dysfunction. This entity was found in 50 adults (mean age, 62 years). Thirty-three had pure aortic valve insufficiency (> or = 3+, n = 13; < 3+, n = 20), 13 had mixed aortic valve insufficiency and stenosis (> or = 3+, n = 2; < 3+, n = 11), and 4 had pure aortic valve stenosis. Forty-one had a history of rheumatic heart disease and advanced mitral valve disease, and 7 had coronary artery disease. All underwent shaving of the hypertrophic protuberances, which in 26 patients constituted the entire aortic valve repair. In the remaining 24 patients, aortic valve repair included one or more additional procedures; there were 15 commissurotomies, 12 debridements of calcium deposits from the base of the cusps, and 5 cusp resuspensions. Concomitant mitral valve repair was performed in 26 patients, mitral valve replacement in 15, tricuspid valve repair in 11, coronary artery bypass grafting in 7, and repair of an ascending aortic aneurysm in 2. In 2 patients, the attempt to repair the aortic valve was unsuccessful, necessitating valve replacement. There were 5 operative deaths (10%), but none were related to aortic valve repair. Forty-three patients entered follow-up (mean, 56 +/- 57 months). Three patients (7%) suffered late recurrent aortic valve insufficiency (at 6, 48, and 72 months). The remaining 40 patients (93%) had trivial or no recurrent aortic valve dysfunction. The 6-year actuarial freedom from aortic valve-related problems was 92%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Real and apparent tuberculin skin test conversions in a group of medical students.

OBJECTIVE: To evaluate tuberculin skin test (TST) conversions among a group of medical students. DESIGN: Questionnaire sent to a medical school class in whom a cluster of TST conversions was noted, and interview and repeat TST of students with conversion. SETTING: County hospital and associated medical school. SUBJECTS: Medical students, after their third year in medical school. RESULTS: Of 165 students in the class, 115 (70%) responded; 10 reported TST conversions between the beginning of the third and the fourth year. Seven of 10 were interviewed, and all 10 were retested. Five students, all in a cohort who tested each other during a clinical clerkship with a tuberculin material previously reported to be associated with a high rate of false-positive TSTs, were TST negative on repeat. Five had persistently positive TSTs. One was exposed during a psychiatry clerkship to a resident with pulmonary tuberculosis. Four students appeared to have converted their TST during their third year in medical school. All four did their medicine clerkship at a large county hospital (P < 0.02; odds ratio = 16.4) that had few infection control measures in place for tuberculosis isolation during the time of their exposure. CONCLUSIONS: We recommend that medical students, as well as other healthcare professions students, be educated about infection control practices and skin tested at least annually during clinical training years.

Chicago↗
PubMed1994

Comparison of Vespula germanica venoms obtained from different sources.

This study was carried out to compare the allergenic potency of Vespula germanica (VG) venoms extracted by different methods and commercially available venoms from Vespula species currently used for in vivo and in vitro studies including immunotherapy. Pure VG venom was used as the reference material. Protein content and enzymatic and allergenic properties of all venoms studied were determined by dye stain reagent, hyaluronidase and phospholipase A1B enzyme activities, and radioallergosorbent test inhibition studies, respectively. Radioallergosorbent test discs sensitized with commercial and pure VG venom were compared using specific IgE antibodies from subjects allergic to VG venom. The data obtained indicate that there were important differences in the allergenic potency between the Vespula species venoms employed for in vivo and/or in vitro assays, VG venom obtained by sac dissection, and pure VG venom. These results indicate that venoms from Vespula species used for in vitro and in vivo tests have a lower concentration of allergens and contain nonvenom proteins. These data should be taken into account when these vespid venoms are used for diagnostic purposes and also when evaluating immunotherapy studies.

Allergens↗
PubMed1994

The impact of aprotinin on coronary artery bypass graft patency.

STUDY DESIGN: Aprotinin has recently been shown to reduce postoperative bleeding and transfusion requirements associated with coronary artery bypass grafting. One concern with its use, however, is that it may have a deleterious effect on graft patency because it promotes hemostasis. Forty-seven patients undergoing coronary artery bypass. Forty-seven patients undergoing coronary artery bypass grafting were enrolled in a prospective, randomized double-blind trial of aprotinin to determine the effect of this agent on postoperative bleeding, transfusion requirements, renal function, and graft patency. The study group was comprised of the 32 patients who underwent technically adequate ultrafast CT scans 6 to 8 weeks postoperatively to determine graft patency. Sixteen patients received aprotinin (aprotinin group) and 16 received placebo (control group). RESULTS: Demographic and operative descriptors were comparable between groups. Postoperative mediastinal and chest tube drainage in the aprotinin group was significantly less than that in the control group (722 vs 1,540 mL; p = 0.0006) and the mean blood transfusion requirements were less, but this did not reach significance (125 vs 297 mL; p = 0.42). Analysis of graft patency by patients revealed that 5 patients in the aprotinin group (31%) had at least one occluded graft, while none of the patients in the control group had an occluded graft (p = 0.04). Analysis by graft revealed that 38 of 43 grafts placed in the aprotinin group were patent, while all 38 grafts placed in the placebo group were patent (88.4 vs 100%; p = 0.057). There was no difference in the incidence of myocardial infarction, renal dysfunction or hematologic indexes at discharge between the groups, or evidence of other thrombotic complications. CONCLUSION: We conclude that high-dose aprotinin is effective in reducing hemorrhage after coronary artery bypass grafting. However, its routine use should be approached cautiously due to its possible adverse effects on graft patency.

Aged↗
PubMed1994

Structure of rotavirus particle: interaction of the inner capsid protein VP6 with the core polypeptide VP3.

The structural relationship between VP6 (inner capsid polypeptide) and the viral core was studied using chemical cross-linking with dithiobis(succinimidyl propionate). Crosslinked single shelled and reconstituted rotavirus particles, suggest the existence of a complex organization of VP6 molecules in the inner capsid and a direct interaction with the core polypeptide VP3. The inhibition of the recovery of RNA polymerase activity associated with the reconstitution of the single shelled particle in the presence of antiVP6 monoclonal antibodies indicates that a VP6 domain between amino acids 56 and 58 seems to be important in viral transcription. A VP6 gene temperature-sensitive mutant (ts G) carrying a mutation affecting assembly of single shelled particles was used in reconstitution experiments. The mutant was able to recover RNA polymerase activity at restrictive temperature. Wild type cores or VP6 were able to reconstitute the particle with both the mutant cores and VP6. These results suggest the existence of various steps for the assembly of single shelled particles, where the VP6-VP3 interaction seems to be important for recovery of RNA polymerase activity.

Antibodies, Viral↗
PubMed1994

Early and late-phase events after valve replacement with the St. Jude Medical prosthesis in 1200 patients.

From May 1982 to August 1991, 1200 patients underwent valve replacement with the St. Jude Medical (St. Jude Medical, Inc., St. Paul, Minn.) valve: 615 men (51%) and 585 women, mean age 58 years. Preoperatively, 830 patients (69%) were in functional class III or IV. A total of 611 patients (51%) had the aortic valve replaced, 490 (41%) the mitral valve, 2 (0.2%) the tricuspid valve, and 97 (8%) multiple valves. There were 81 hospital deaths (6.8%). Risk factors included older age (p = 0.0001), female gender (p = 0.02), higher preoperative left ventricular end-diastolic pressure (p = 0.05), previous cardiac operation (p = 0.003), longer aortic crossclamp time (p = 0.0001), and longer cardiopulmonary bypass time (p = 0.0001). Follow-up was 98% complete (3153 patient-years). There were 152 late deaths; 32 (21%) were considered valve-related: six thromboembolism, four valve thrombosis, five anticoagulant-related hemorrhage, eight prosthetic valve endocarditis, one paravalvular leak, and seven sudden death. The 5-year actuarial survival was 75%. Risk factors for late death included older age (p = 0.03), lower preoperative ejection fraction (p = 0.005), longer aortic crossclamp time (p = 0.001), longer cardiopulmonary bypass time (p = 0.0001), previous cardiac operation (p = 0.02), and higher preoperative functional class (p = 0.0001). Actuarial freedom at 5 years from major thromboembolic events and anticoagulant-related hemorrhage was 97% and 95%, respectively. This value for valve thrombosis was 99%, for reoperation 96%, for prosthetic valve endocarditis 98%, and for paravalvular leak 96%. Actuarial freedom from all valve-related events and valve-related death at 5 years was 74% and 94%, respectively. We conclude that the low incidence of valve-related events and low mortality supports the continued use of the St. Jude Medical valve.

Actuarial Analysis↗
PubMed1993

Identification of cysteine residues at the 10-pmol level by carboxamidomethylation of protein bound to sequencer membrane supports.

A procedure is described for the in situ carboxamidomethylation of cystine/cysteine residues in protein samples of as little as 10 pmol, prior to automated protein sequence analysis. Previous in situ methods for the modification of cysteines are limited to proteins available in quantities greater than 100 pmol due to contaminants which interfere with HPLC identification of phenylthiohydantoin amino acids, and cannot be performed on polyvinylidenedifluoride (PVDF)-bound samples. In our procedure, protein samples, immobilized on either PVDF- or polybrene-treated glass filters, are reduced with tributylphosphine followed by alkylation with iodoacetamide prior to automated sequence analysis. Carboxamidomethylcysteine is formed in high yield with no discernable side reactions in standard proteins (insulin, human transferrin, lysozyme) or experimental samples. Both initial and repetitive yields of carboxamidomethylated proteins were either comparable to or better than nonalkylated proteins. No apparent increase in background nor any sequence preview due to partial amino-terminal alkylation was observed. The carboxamidomethylation procedure described here successfully overcomes the limitations of available methods for reduction and alkylation of less than 100 pmol of protein directly on sequencer membrane supports.

Alkylation↗
PubMed1993

Chronic type A aortic dissection: an unusual complication of cocaine inhalation.

Acute aortic pathology temporally related to cocaine inhalation may lead to frank rupture or acute aortic dissection. This is a report of an unusual case of a 43-year-old man who presented 9 weeks after experiencing a tearing sensation in his chest while smoking cocaine. The diagnosis was chronic type A aortic dissection with 4+ aortic insufficiency. The successful surgical management included resuspension of the aortic valve and placement of a Dacron tube graft in the ascending aorta such that flow was maintained distally in both the true and false lumens.

Administration, Inhalation↗
PubMed1993

Management of an innominate artery aneurysm during an open heart operation.

A 76-year-old woman was found to have a 4 x 2.5-cm saccular aneurysm at the origin of the innominate artery at the time of a reoperative open heart operation. The operative procedure was modified to include repair of the aneurysm with a Dacron patch. During the period of innominate artery occlusion, the patient was cooled to 25 degrees C and the mean arterial pressure was maintained at 90 mm Hg to maximize cerebral protection.

Aged↗
PubMed1993

Effects of a short prednisone regime at clinical onset of type 1 diabetes.

The effect of corticosteroids on beta cell function and humoral immune response in type 1 diabetes was tested in a 2-month trial conducted on 32 newly diagnosed patients (age 22.8 +/- 1.4 years, mean +/- S.E.M.). Prednisone was administered at immunosuppressive dosage (1 mg.kg-1.day-1) during the initial 10 days and at a maintenance dosage (0.3 mg.kg-1.day-1) for 50 days. Patients (n = 32) were enrolled within 6 weeks after diagnosis and matched in pairs for age, sex, presence of islet cell antibodies (ICA) and glucagon stimulated C-peptide levels. Insulin discontinuation was not contemplated. All the patients who received prednisone became ICA during treatment but in some (4 out of 10) this effect was only transient. Insulin antibodies (IA) were significantly lower in the prednisone group at second and third month (P < 0.05). No patient experienced complete remission but in 10 prednisone and 4 control patients the insulin requirements were below 0.3 IU/kg (P < 0.05). With similar glycemia the fasting C-peptide levels were higher in the treated patients. The profile of the insulin requirements during the follow-up was different in the two groups and at 9 months the prednisone group needed less insulin than the control (P < 0.05). Interestingly, within the prednisone-treated group and after 6 months, the levels of stimulated C-peptide improved significantly among the ICA+ patients while they were steady or declined in ICA- (P < 0.01). The analysis of variance covariance confirmed a positive interaction between ICA and the administration of prednisone on the outcome of beta cell function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Decreased tyrosine hydroxylase mRNA but not cholecystokinin mRNA in the pars compacta of the substantia nigra and ventral tegmental area of aged rats.

Quantitative in situ hybridization histochemistry was used to determine the age-related changes in tyrosine hydroxylase (TH) mRNA and cholecystokinin (CCK) mRNA in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) of the rat. Coronal sections (10 microns) were cut in a cryostat through the VTA and SNc of brains from 3 months and 33 month old Sprague-Dawley rats and immediately adjacent sections hybridized with 35S-labelled 45-mer oligonucleotide probes specific for either the rat TH or CCK genes. The mRNA levels of each gene were estimated by computerised densitometric analysis of the signal on X-ray film autoradiograms and estimation of the number of mRNA expressing cells as well as the density of expression per cell (grain density) was made from high resolution emulsion autoradiograms. Analysis of the TH mRNA on X-ray film autoradiograms indicated that the levels averaged 25% lower in the SNc (P < 0.01) and 18% lower in the VTA (P < 0.05) of the old rats. However, analysis of the emulsion autoradiograms showed that this reduction in TH mRNA in the VTA and SNc in the old rats was not due to a loss of TH mRNA expressing cells but due to a reduction in the hybridization signal per expressing cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Valve-related events and valve-related mortality in 340 mitral valve repairs. A late phase follow-up study.

To assess the early and late valve-related events, 340 consecutive patients undergoing mitral valve repair from 1969 to 1988 were evaluated. Follow-up was complete, with a mean of 7.5% years and range from 2 to 22 years (cumulative 2456 patient-years). There were 221 (65%) female patients. Rheumatic valvular disease was present in 246 (68%) patients. The remaining patients had ischemic or congenital valve disease, floppy valve or infective endocarditis. At surgery, 47% of the patients had pure mitral incompetence, 43% had mixed mitral stenosis and incompetence and 10% had predominant mitral stenosis. Seventy-three percent of the patients were in functional class III or IV. Twelve percent had had prior heart surgery. Concomitant valve procedures including coronary revascularization were performed in 62.3%. There were 23 hospital deaths (6.8%) but only 3 of these (0.8%) were valve-related in patients who died at reoperation for valve repair failure. There were 4 other early repair failures who survived early reoperation. Of the 317 hospital survivors, there were 127 late deaths, and an actuarial survival of 44 +/- 3.7% (70% CL) at 14 years. Of these, 13 were valve-related or 0.5% patient-year. Late events included thromboembolism (TE) 1% patient-year, anticoagulant bleeding 0.4% patient-year, infective endocarditis (IE) 0.2% patient-year and late reoperation for mitral valve repair failure in 63 patients or 2.8% patient-year. At the late follow-up, 88% of the hospital survivors were in functional class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1993

Use of murine subinoculation for the diagnosis and isolation of toxoplasmosis in HIV-infected patients with persistent lymphadenopathy.

A murine model was used to try to elucidate the importance of Toxoplasma gondii infection in HIV-positive patients. Laboratory mice were inoculated with lymph node homogenates or buffy coats from 30 HIV-infected individuals with persistent lymphadenopathy. Sabin and Feldman dye-tests, direct agglutination tests and indirect immunofluorescence assays (IFA) of serum samples taken from the mice six weeks after inoculation indicated, respectively, that 26.6%, 43.4% and 33.3% of the lymph node inocula and 13.3%, 30.0% and 16.7% of the buffy coat samples had been Toxoplasma-positive. Histological examination of the brains of the infected mice revealed Toxoplasma tachyzoites or bradyzoites in the mice given buffy coat samples from one patient (3.3%) and those given lymph node material from three patients (10%). No protozoa were found in the brains of the control mice, all of which were sero-negative. In contrast to the mouse results, other, concurrent tests failed to detect any signs of toxoplasmosis infection in the patients, except relatively low titres of anti-Toxoplasma antibodies in 11 patients, even though two patients developed brain toxoplasmosis, one 12 and the other 18 months after the study. It appears, therefore, that an animal model can be very useful in the diagnosis of toxoplasmosis in HIV patients.

AIDS-Related Complex↗