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Biomedical subjects

L Perez

Publications and source records attributed to L Perez.

At least 73 records · Page 4Linked to original sources

Influence of family planning counseling in an adolescent clinic on sexual activity and contraceptive use.

We evaluated whether family planning counseling (FPC) in an adolescent clinic promoted the onset of sexual activity among the non-sexually active teens and/or increased contraceptive use among the sexually active teens. The FPC focused on the teens' establishing sexual values, the right to say "no," abstinence and alternate forms of intimacy, consequences of intercourse, and the various contraceptive methods. Data for one year were collected on the adolescents' first and subsequent visits to a medically oriented, municipal outpatient adolescent clinic. There were 383 teenagers who qualified for the study. Of these, 35% (134) reported premarital sexual activity. During the study period, 3% (8) of the 249 nonsexually active teens reported becoming sexually active. Among the 134 sexually active teens at clinic entry, 27% reported using a contraceptive method at their most recent sexual encounter. Among the 142 sexually active adolescents at the conclusion of the study, 76% reported contraceptive use at their most recent sexual encounter (p less than 0.001). We conclude that the provision of FPC to nonsexually active and sexually active teens does not appear to promote the onset of sexual activity significantly among the non-sexually active group, although it significantly increases contraceptive use among the sexually active group.

Adolescent↗

Expression of the Rous sarcoma virus env gene from a simian virus 40 late-region replacement vector: effects of upstream initiation codons.

Expression of the Rous sarcoma virus envelope gene (env) from a simian virus 40 (SV40) late-region replacement vector is dependent on the position of env within the SV40 late-region sequences. The difference in expression levels appeared to be due to differences in the efficiency with which the env-specific transcripts were translated, because transcription levels from different constructions were similar. Deletion of the nucleotides encoding the agnoprotein initiator codon, located upstream of the env sequences in the poorly expressed construct, resulted in high levels of env expression. The agnoprotein initiator codon and overlapping open reading frame thus act as strong barriers to further ribosome scanning and prevent initiation at the env AUG codon. We conclude that AUG codons present in the late region of SV40 can reduce expression of inserted genes positioned downstream. Nevertheless, intrinsic properties of the gene may determine its ultimate level of expression.

Animals↗

Complete amino acid sequence of flavocytochrome b2 from baker's yeast.

Each subunit of baker's yeast flavocytochrome b2 can be selectively cleaved by proteases into two fragments, amino-terminal fragment alpha and carboxy-terminal fragment beta. The primary structure of the former has been reported before [Ghrir, B., Becam, A. M. & Lederer, F. (1984) Eur. J. Biochem. 139, 59-74]. The amino acid sequence of the 197-residue fragment beta has now been established. The fragment was cleaved with cyanogen bromide; the three peptides thus obtained were submitted to digestions with Staphylococcus aureus V8 protease, chymotrypsin and trypsin, sometimes after succinylation. The complete fragment was also submitted to tryptic cleavage after citraconylation. Peptides were separated by thin-layer finger-printing or high-pressure liquid chromatography. They were mostly sequenced in a liquid-phase sequenator. The 511-residue amino acid sequence of the mature protein is thus completely established. Secondary structure predictions indicate an alternation of helical and extended structure, with a higher percentage of the former. Comparisons with other flavoproteins do not detect any significant sequence similarity.

Amino Acid Sequence↗

Nutritional status of children in the health district of Cusco, Peru.

This study was conducted to obtain an accurate assessment of the nutritional status of the children in the Cusco, Peru Health District. It is a sample survey of anthropometric measures for 3,383 children under the age of 10 yr. The results showed a significant decline in nutritional status with age (96.88% normal range at ages 1-3 mo to only 37.43% normal at ages 12-24 mo) followed by a gradual improvement in the children above 2 yr (approximately 50% normal). The deficits at the older ages were principally due to low weights-for-age. Nutritional status was also dependent on sex, village altitude, remoteness, and population size (p less than 0.005). Of these, only sex interacted with age. The girls did significantly better at some ages and the boys better, but not significantly so, at other ages.

Age Factors↗

Regulation of hematopoiesis in rats exposed to antiorthostatic, hypokinetic/hypodynamia: I. Model description.

This paper provides baseline information regarding the regulation of hematopoiesis in antiorthostatic, hypokinetic/hypodynamic ("suspended") laboratory rats. The object of the study was to compare the hematological effects of suspension with those seen following space flight in man and/or rats. Observed in man after exposure to microgravity and in the suspended rats was a reduced red blood cell mass, suppressed erythropoiesis, a transient increase in hematocrit due to a reduction in plasma volume, a post-exposure hematocrit decrease, a weight loss (or failure to thrive) and a reduction in food and water consumption. A rightward shift in the oxyhemoglobin dissociation curve, observed in the rat "model", has been predicted to occur during manned space flight but has not yet been measured. Suppression of hematopoiesis is a common feature of rats during both space flight and suspension. Platelet counts showed no significant change in rats after suspension or in man during space flight. Unlike man in space but similar to space flight-exposed rats, no significant change in leukocyte number or reactivity to PHA in vitro, or in red blood cell shape distribution were observed in the suspended rats. At least in a gross sense, the rat "model" seems to reproduce many of the known hematological effects of space flight and offers promise as a 1 X g analog for understanding hematopoietic effects similar to those found in space flight.

Animals↗

Fertility and ovum transport after microsurgical removal of the uterotubal junction in rabbits.

The role of the uterotubal junction (UTJ) in fertility and ovum transport was investigated following unilateral microsurgical resection of the UTJ in 15 rabbits. Fourteen animals became pregnant on the UTJ resected side and 14 on the control side following artificial insemination and induction of ovulation. Fifty-two of 61 ova (85.2%) became implanted on the control side, and 56 of 68 ova (82.3%) became implanted on the resected side. Ten days after delivery, artificial insemination and induction of ovulation were repeated. Ovum transport was examined at 60, 66, and 72 hours. There was no significant difference in ovum transport between UTJ resected and control sides. The distribution of ova within the oviduct and the time of their entrance into the uterus was comparable in both sides. These results indicate that the UTJ is not necessary for normal fertility and ovum transport in the rabbit.

Animals↗

Endoscopic myotomy in the treatment of achalasia.

Seventeen patients with achalasia were treated by endoscopic myotomy limited to the esophageal rosette and avoiding the distal antireflux zone. Clinical, radiological, endoscopic, and manometric follow-up revealed improvement comparable to that seen in patients after successful surgical myotomy or pneumatic dilation. In the hands of the authors, the procedure has been simple, fast, effective, and safe, thus providing an alternative treatment of achalasia.

Animals↗

Mecrowear of mammalian teeth as an indicator of diet.

Microwear details on teeth of two sympatric species of hyrax are correlated with major dietary differences observed in the wild. Grazing (Procavia john-stoni) and browsing (Heterohyrax brucei) species can be distinguished. The results show that diets of extinct species may be deduced from tooth microwear.

Animals↗

Metastatic disease of the paraspinal muscles: electromyographic and histopathologic correlation in early detection.

Electromyographic examination may demonstrate severe segmental compromise of the posterior primary ramus and relative sparing of the anterior ramus as the earliest objective evidences of spinal and paraspinal metastases. Antecedent studies, including roentgenographic, radioisotopic and neurologic investigations, are often initially normal, failing to reveal the underlying cause of the progressive back pain. The present report demonstrates metastatic spread both through the paravertebral venous plexus and by direct extension in contiguous muscle. In this special instance, segmental 4+ fibrillations in the paraspinal muscles are electrophysiologic manifestations of a local, active process of denervation rather than a remote effect of the malignant disease, as has been suggested by others.

Adenocarcinoma↗

The messianic idea and messianic delusion.

The messianic delusional syndrome repeats an historical prototype that manifests itself in each patient with individual changes. The syndrome expresses a serious impairment of identity and reflects a social, cultural and religious reality through generations. The regularities of its clinical features comprise a delusional system, centered on the patient's conviction that he has been chosen by God for a special and intransferable mission. The patient has special powers for carrying out this mission. He is a savior and announces resurrection. His delusions have a clear symbolic character. For the patient's social group, the messianic idea is an attempt at annulling the effect of oppression or persecution that have become unbearable for the individual. They represent a flight from the human sphere and an attempt to be God. The patient's behavior is in consonance with this purpose; it expresses itself, on the one hand, through preaching repentance and compassion and, on the other hand, the patient gives up his earthly links and replaces them by parental relations with God. In the above-mentioned context, the author analyzes the different elements of the religious conception in the Christian, Moslem and Jewish religions, and the way each of them expresses itself in the general symptomatology.

Adult↗

Retrograde pancreatography: new contributions.

The standard technic for pancreatography was modified by using a metallic guide wire in the proximal half of the cannula so as to regulate pressure independently from that applied manually. The maximum pressure obtained by this method was measured in a polyethylene teflon cannula constructed to correspond to the Wirsung duct. Pressure was five times less when the guide wire was used. Our results in 33 patients correspond to experimental data. Only in 28% of our cases did the amylase rise slightly to a maximum of 290 Somogyi units. Acinar opacification was attempted by adding NaCO3 to a standard dye solution and was obtained in 20% of the cases (5 of 25). Maximum amylase elevation in this group was 263 Somogyi units. No complications resulted from the pressure measurements during pancreatography.

Adolescent↗

Endoscopic, radiologic and manometric correlation in small sliding hiatal hernia.

Of the three methods employed, endoscopy seems to be the most accurate since it permits identification of both anatomical structures and serves as a basis for interpretation of radiology and manometry. Cardial incisura was the easiest and most constantly identifiable structure by the three methods. It must be considered as the union between esophagus and stomach. In small sliding hiatal hernia, the cardial incisura remains below the diaphragm and the gastric mucosa slides up into the chest, resulting in a partial prolapse (hiatal hernia of sliding mucosa). This concept would clarify the difference in interpretation of the most commonly used procedures in diagnosis of sliding hiatal hernia.

Esophagogastric Junction↗