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Biomedical subjects

J M Lopez

Publications and source records attributed to J M Lopez.

15 recordsLinked to original sources
PubMed1992

Surveillance in evacuation camps after the eruption of Mt. Pinatubo, Philippines.

To obtain accurate, timely data on the health status of persons in evacuation camps after the eruption of the Mt. Pinatubo volcano, the Philippine Department of Health (DOH) conducted a survey of the health needs of the evacuees and established disease surveillance in each camp. Surveys of the camps revealed that sources of potable water, sanitary means of waste disposal, and shelters were inadequate. Disease surveillance showed that measles, acute respiratory infections, and diarrhea were the most important problems. Surveillance detected outbreaks of measles and an outbreak of vomiting and diarrhea in the camps. Deaths, primarily caused by measles (31%), diarrhea (29%), and respiratory infections (22%), totaled 349 in the first 12 weeks. Death rates peaked in the seventh week, when a death rate of 26/10,000 occurred among the Aetas, a tribe evacuated from the slopes of the volcano. The surveys guided the DOH in allocating supplies and medicine, while disease surveillance enabled disaster managers to monitor the effectiveness of health programs, identify high-risk groups, and respond appropriately to the situation.

Diarrhea↗
PubMed1992

Comparison of a new commercial enzyme immunoassay for rapid detection of respiratory syncytial virus.

Two rapid methods for detection of respiratory syncytial virus in respiratory specimens were compared: direct immunofluorescence assay (DFA) with monoclonal antibody and an enzyme immunoassay (EIA) (Test-Pack RSV). Ninety-five nasopharyngeal washings and aspirates from 51 children were examined; the patients were hospitalized during a winter outbreak of RSV infection in the first trimester of 1990. A total of 41.0% and 56.8% of these samples were positive by EIA and DFA respectively. Considering only the 51 specimens collected at the onset of illness, EIA detected 72.5% positive samples and DFA detected 78.4%. In comparison with DFA, EIA was 92.5% sensitive and 100% specific for the acute phase of illness. When all the samples were taken into account, specificity was maintained but sensitivity fell to 72.2%. The results show that both methods are useful during the acute phase of the illness, when the viral load is important. However, later on in the course of the infection DFA appears to be more sensitive than EIA.

Female↗
PubMed1992

Growth hormone (GH) receptor antibodies with GH-like activity occur spontaneously in acromegaly.

Previous studies in our laboratory have identified a portion of big-big GH as actually being anti-GH receptor immunoglobulins. We now report the isolation of two types of anti-GH receptor antibodies from the serum of active acromegalic patients. One of them (patient A) interferes with the human GH RIA, thus overestimating the real plasma GH values. The other type of immunoglobulin G (IgG; patient B) was detected in an acromegalic patient with almost normal immunoreactive GH level. The main aim of the present study was to explore whether these anti-GH receptor IgGs possess GH-like biological activity. The IgGs of both patients were isolated by chromatography on Sephadex G-100 and then on protein-A-Sepharose. In the bioassay, cultured Nb2 lymphoma cells were incubated with hGH standards and serial dilutions of the purified IgGs, and cell proliferation was used as a measure of biological activity. The IgGs of both patients showed GH-like bioactivities, which, when calculated as equivalents of human GH, correspond to approximately 260 and 120 micrograms/L, respectively. The results suggest that biologically active anti-GH receptor antibodies may contribute in the pathology of some cases of acromegaly.

Acromegaly↗
PubMed1991

Decentration of intraocular lenses implanted after intercapsular cataract extraction (envelope technique).

Pseudophakos decentration produces symptoms such as glare, halos, and other visual aberrations. We have reviewed 161 eyes of patients who had an intercapsular cataract extraction with intraocular lens (IOL) implantation with a follow-up of at least six months. Mean decentration was 0.54 mm. It was 0.46 mm for the lenses implanted symmetrically in the bag, 0.65 mm for those implanted in the sulcus, and 0.91 mm for those implanted asymmetrically (bag-sulcus). The differences between the lenses fixated in the bag and those asymmetrically situated were statistically significant (P less than .001). Circular looped lenses (360-degree encircling loop) decentered less (mean 0.28 mm) than modified C-loop lenses (mean decentration 0.63 mm) and modified J-loop lenses (mean decentration 0.60 mm). These differences were statistically significant (P less than .001). The differences were also significant if we considered only the lenses implanted in the bag (mean decentration 0.20 versus 0.59 and 0.54, respectively) (P less than .0001).

Aged↗
PubMed1991

Identification of a membrane glycoprotein found primarily in the prelysosomal endosome compartment.

Cells contain an intracellular compartment that serves as both the "prelysosomal" delivery site for newly synthesized lysosomal enzymes by the mannose 6-phosphate (Man6P) receptor and as a station along the endocytic pathway to lysosomes. We have obtained mAbs to a approximately 57-kD membrane glycoprotein, (called here plgp57), found predominantly in this prelysosomal endosome compartment. This conclusion is supported by the following results: (a) plgp57 was primarily found in a population of late endosomes that were located just distal to the 20 degrees C block site in the endocytic pathway to lysosomes (approximately 83% of the prelysosomes were positive for plgp57 but less than 5% of the early endosomes had detectable amounts of this marker); (b) plgp57 and the cation-independent (CI) Man6P receptor were located in many of the same intracellular vesicles; (c) plgp57 was found in the membranes of an acidic compartment; (d) immunoelectron microscopy showed that plgp57 was located in characteristic multilamellar- and multivesicular-type vacuoles believed to be prelysosomal endosomes; and (e) cell fractionation studies demonstrated that plgp57 was predominantly found in low density organelles which comigrated with late endosomes and CI Man6P receptors, and only approximately 10-15% of the antigen was found in high density fractions containing the majority of secondary lysosomes. These results indicate that plgp57 is a novel marker for a unique prelysosomal endosome compartment that is the site of confluence of the endocytic and biosynthetic pathways to lysosomes.

Animals↗
PubMed1979

The decrease of guanine nucleotides initiates sporulation of Bacillus subtilis.

Massive sporulation of Bacillus subtilis normally begins when carbon, nitrogen or phosphorus sources able to support rapid growth are no longer available. Sporulation can also be induced in exponentially growing cultures, in the presence of rapidly utilizable ammonia, glucose and phosphate if growth is partially but not completely inhibited either by inhibitors of nucleotide synthesis (hadacidin, decoyinine or 6-azauracil) or by purine deprivation in purine and especially in guanine auxotrophs. All these conditions allowing sporulation result in a decrease in the intracellular concentration of guanosine di- and tri-phosphates and usually uridine di- and triphosphates while other nucleotides decrease in some but increase in other cases. A decrease of uracil nucleotides alone, in a uracil auxotroph, does not produce massive sporulation. Our results demonstrate that the partial reduction of a guanine nucleotide, probably relative to some other compound, suffices to initiate sporulation. This reduction may always play a decisive role in the initiation of sporulation, as we have observed it under all conditions so far known to produce massive sporulation.

Bacillus subtilis↗
PubMed1977

Role of sugar uptake and metabolic intermediates on catabolite repression in Bacillus subtilis.

Many phosphorylated intermediates exert catabolite repression on the enzyme acetoin dehydrogenase in Bacillus subtilis. This was shown with strains that are blocked at different positions in central metabolism when they receive sugars that cannot be metabolized past enzymatic block(s). In the case of sorbitol, transport events were not involved in catabolite repression, for this sugar cannot repress acetoin dehydrogenase in a strain lacking sorbitol dehydrogenase but otherwise able to take up sorbitol. The presence of glucose did not markedly influence the uptake of acetoin.

Acetoin↗
PubMed1976

Diagnosis of Björk-Shiley aortic valve dysfunction by echocardiography.

Echocardiography was performed on 26 patients with prosthetic Björk-Shiley aortic valves (BSAV). Technically satisfactory records were obtained in 22 patients. The systolic displacement of the valve disc varied from 1 to 1.8 cm. (mean, 1.4 cm.). Six patients developed valve dysfunction. Two patients had complete absence of Björk disc motion and dense echoes in the aortic root were noted on the echocardiogram. Extensive clot formation in and around the valve was seen at operation. After clot removal, these two echocardiograms showed excellent disc motion (1.5 and 1.8 cm.). In a third patient with a clotted valve, marked reduction of the velocity of opening and closing of the valve was noted. Three patients had aortic incompetence without evidence of clot formation. Normal disc motion (DM) was observed in all three. A seventh patient presented with a low output state and markedly reduced valve clicks. Echocardiography revealed normal DM with marked dilatation of the left ventricle. These features were confirmed by angiography. We conclude that: (1) satisfactory echocardiograms can be obtained in most patients with BSAV; (2) echocardiography may be a useful method of detecting Björk valve dysfunction.

Adult↗
PubMed1975

Echocardiographic observations on the mechanism of production of the second heart sound.

This investigation was designed to determine the echocardiographic correlates of the aortic and pulmonary components of the second heart sound. Simultaneous recordings of the ECG, phonocardiogram, carotid pulse tracing and the echocardiogram of the aortic valve were made in 54 patients. The tracings were recorded at a paper speed of 100 mm/sec, with 20 msec time lines. Aortic valve closure (AVC) on the echocardiogram occurred before the onset of the aortic component of the second heart sound (A2) in all but two patients. The mean AVC-to-A2 interval was 12 msec with a range of 5 to 25 msec. Simultaneous recordings of the pulmonary valve echocardiogram, ECG, phonocardiogram and carotid pulse tracing were made in 14 patients. Pulmonary valve closure (PVC) on the echocardiogram preceded the pulmonary component of the second sound (P2) in all patients. The mean PVC-2 interval was 60 msec with a range of 30 to 75 msec. We conclude that aortic valve closure and pulmonary valve closure are not directly responsible for the genesis of the second heart sound (S2). These observations are consonant with the theory that S2 is caused by deceleration of columns of blood resulting from semilunar valve closure, throwing the cardiohemic system into vibration.

Adolescent↗
PubMed1975

Echocardiographic detection of tricuspid valve prolapse.

The echocardiographic findings in 12 patients with tricuspid valve prolapse are presented. Eight of these patients had associated mitral valve prolapse. Only one of the above patients had the characteristic physical signs of tricuspid incompetence. Two types of abnormality were noted on the echocardiogram of the tricuspid valve. In eight patients, the systolic segment of the tricuspid valve showed an initial horizontal motion followed by a posterior motion in midsystole. Four patients exhibited posterior motion of the tricuspid valve in early systole, which reached a maximum in midsystole, and this was followed by an anterior motion, thus producing a hammock-like configuration. We conclude that echocardiography is useful in the diagnosis of tricuspid valve prolapse. Since this condition may be associated with clinically significant tricuspid incompetence or bacterial endocarditis, its recognition is of clinical importance.

Adolescent↗
PubMed1975

[Radiological appearances of cancer of the gastric stump (author's transl)].

The authors report 35 cases of primary carcinoma of the gastric stump, describing the technique they use for radiography, noting the main diagnosis signs and discussing the importance of the various methods for their study. They emphasize the importance of periodic post-operative control in these cases.

Adult↗
PubMedDate not supplied

Idiopathic hypertrophic subaortic stenosis in the elderly.

In a 24-month period, 27 patients with idiopathic hypertrophic subaortic stenosis (IHSS), ages 65-80 years, were observed. Diagnoses were made by echocardiography (24 patients), cardiac catheterization (one patient), and both methods (two patients). The most common symptoms were angina (17 patients), dyspnea (13 patients), and syncope (11 patients). Two patients were asymptomatic, while another complained only of vague retrosternal chest discomfort with exertion. One asymptomatic patient had a completely normal physical examination, but electrocardiography (ECG) demonstrated a pattern of left ventricular hypertrophy. Another patient had an inconsistent apical holosystolic murmur. Two patients had alpha streptococcal endocarditis; neither was known to have pre-existing valvular disease. Fourteen patients had ECG criteria for left ventricular hypertrophy (LVH). Three patients were known to have associated aortic valve disease. The symptoms of IHSS may be nonspecific; asymptomatic patients with and without cardiac murmurs may be observed. Coexisting valvular disease, coronary artery disease, and bacterial endocarditis were documented. Patterns of myocardial infarction on ECG were not seen in these 27 patients.

Aged↗
PubMedDate not supplied

Characterization of chick serum lipoproteins isolated by density gradient ultracentrifugation.

Serum lipoproteins from 12h fasted male chicks (15-day-old) were separated into 20 fractions by isopycnic density gradient ultracentrifugation. A new procedure was described by collecting the different fractions from the bottom of tube instead of by aspiration from the meniscus of each tube. Analyses of chemical composition of serum lipoproteins have permitted to reevaluate the density limits of major classes: VHDL, d greater than 1.132 g/ml; HDL, d 1.132-1.084 g/ml; LDL, d 1.084-1.038; IDL, d 1.038-1.022; and VLDL d less than 1.022. HDL fractions clearly predominated (approx. 77% of total lipoproteins) while IDL and VLDL were present at low percentage. LDL was the fraction richest in cholesterol; triacylglycerol content clearly increased from HDL to VLDL, while protein content decreased. All the chemical components of chick serum lipoproteins were accumulated in HDL, although triacylglycerol was relatively distributed in all the lipoprotein classes.

Animals↗