RESUMEN
Digital image analysis of seeds has been used for the identification of cultivars, determination of seed color and mechanical damage, and classification of different seed sizes. The aim of the present study was to evaluate the efficiency of digital image analysis of seeds for the quantification of genetic diversity among genotypes of inbred guava (Psidium guajava L.) families. The SAS Mini equipment, which consists of a capture module and a software program for analysis, was employed for the capture and analysis of the seed images. Different genetic diversity quantification strategies were tested using the Ward-Modified Location Model method. The set of variables related to geometry of the seeds was the largest contributor to divergence among the guava genotypes. The use of seed descriptors obtained by digital image analysis via the SAS system was efficient at quantifying the genetic diversity among genotypes of inbred guava families associated with the use of the Ward-Modified Location Model method.
Asunto(s)
Psidium/genética , Computadores , Frutas/química , Variación Genética , Genotipo , Procesamiento de Imagen Asistido por Computador/métodos , Fenotipo , Fitomejoramiento/métodos , Psidium/química , Semillas/química , Semillas/genéticaRESUMEN
Recent reports have described a distinct and recurrent pattern of systemic malformation that associates craniosynostosis and neurodevelopmental abnormalities with many clinical features of the Marfan syndrome (MFS), an autosomal dominant disorder of the extracellular microfibril caused by defects in the gene encoding fibrillin-1, FBN1 (ref. 8). Additional common findings include other craniofacial anomalies, hypotonia, obstructive apnea, foot deformity, and congenital weakness of the abdominal wall. So far, only 11 cases have been reported precluding the assignment of definitive diagnostic criteria. While it remains unclear whether these cases represent a discrete clinical entity with a single aetiology, they have been pragmatically grouped under the rubric Marfanoid-craniosynostosis or Shprintzen-Goldberg syndrome (SGS). Because of the significant clinical overlap between MFS and SGS, we proposed that they may be caused by allelic mutations. We now report two SGS patients who harbour mutations in FBN1. While it remains unclear whether these mutations are sufficient for the clinical expression of the entire SGS phenotype, these data suggest a role for fibrillin-1 in early craniofacial and central nervous system development. Our recent observation that FBN1 transcript is expressed as early as the 8-cell stage of human embryogenesis is consistent with this hypothesis.
Asunto(s)
Anomalías Múltiples/genética , Craneosinostosis/genética , Proteínas de Microfilamentos/genética , Mutación Puntual , Anomalías Múltiples/fisiopatología , Secuencia de Aminoácidos , Secuencia de Bases , Niño , Craneosinostosis/fisiopatología , Análisis Mutacional de ADN , Femenino , Fibrilina-1 , Fibrilinas , Humanos , Lactante , Masculino , Síndrome de Marfan/genética , Síndrome de Marfan/fisiopatología , Técnicas de Sonda Molecular , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , SíndromeRESUMEN
Gynaecomastia has been associated with a large variety of drugs in the literature. However, a causal relation of the incidence of gynaecomastia to a certain drug should be considered only if sufficient and significant evidence can be obtained from the studies published. In this review, studies quoted in Medline were evaluated according to the Scottish Intercollegiate Guidelines Network (SIGN) grading system for clinical studies. Reports on 92 drugs were found in Medline in combination with gynaecomastia. An imbalance of the oestrogen/androgen ratio causes gynaecomastia. Also, prolactin has gynaecomastia-inducing properties. In 14 of the drugs quoted, the studies lead to a level of recommendation 'A'. All these drugs have been designed to interfere with the production and action of sexual hormones or of prolactin. In 25 of the drugs, the level of recommendation was 'B'. Besides those drugs in this group that have been designed for interference with the metabolism of steroid hormones or of prolactin, in drugs for acid-related disorders, diuretics, antiretroviral drugs, antimycotics, psychoanaleptics, alcohol gynaecomastia was described as an unexpected adverse effect. Studies on the association of drugs and gynaecomastia do not share a generally accepted definition of gynaecomastia; in this way, the informational value is limited.
Asunto(s)
Ginecomastia/inducido químicamente , Humanos , MasculinoRESUMEN
The university museum for cultural history in the castle of Marburg has a portrait "Die grosse Barb", which represents a women suffering from acromegaly. She shows the typical pathologic alterations: thickening of the skin folds, thickening of the lips and the eyelids, growth of bones and cartilages, lengthening of the nose, enlargement of the ears, protrusion of the zygoma, mandible and the chin. Acromegaly is a consequence of enhanced secretion of growth hormone, which occurs also as a symptom of several syndromes, such as multiple endocrine neoplasia type 1, McCune-Albright-syndrome, and NAME syndrome (Carney complex type I). The most remarkable symptom of acromegaly is the gigantism. This occurs also in androgen-deficient states, such as the Klinefelter syndrome and some more genetic syndromes, of which the Simpson-Golabi-Behmel syndrome, the Sotos syndrome, the Marfan syndrome, the homocystinuria, and the fragile X-syndrome may be mentioned. Nothing is known on the further fate of the patient shown in the portrait. It is also unknown, whether she owes her position as a chambermaid to her gigantism, for it was a common use in courts to have people with abnormal body shapes in attendance.
Asunto(s)
Acromegalia/historia , Medicina en las Artes , Museos , Pinturas/historia , Femenino , Alemania , Historia del Siglo XVI , HumanosRESUMEN
Male accessory gland infection (MAGI) is a consequence of canalicular spreading of agents via urethra, prostate gland, seminal vesicles, deferent duct, epididymis and testis. Haematogenous infections are rare. The main infectious agents are Neisseria gonorrhoeae and Chlamydia trachomatis, and also enterobacteriae at a lesser frequency. Characteristic symptoms of MAGI are leukocytospermia, enhanced concentration of cytokines and reactive oxygen species. As complications, obstruction of the ductus epididymidis and/or another duct section, impairment of spermatogenesis in orchitis, impairment of sperm function, and dysfunctions of the male accessory glands may occur. Reduction of male fertility is a rare consequence. The treatment has to consider specific antibiotics.
Asunto(s)
Enfermedades de los Genitales Masculinos/microbiología , Genitales Masculinos/microbiología , Antibacterianos/uso terapéutico , Infecciones por Chlamydia/complicaciones , Infecciones por Chlamydia/diagnóstico , Infecciones por Chlamydia/tratamiento farmacológico , Chlamydia trachomatis/patogenicidad , Enfermedades de los Genitales Masculinos/complicaciones , Enfermedades de los Genitales Masculinos/tratamiento farmacológico , Gonorrea/complicaciones , Gonorrea/diagnóstico , Gonorrea/tratamiento farmacológico , Humanos , Masculino , Neisseria gonorrhoeae/patogenicidadRESUMEN
Isolated human gastric glands from surgical specimens were preincubated in an oxygenated medium with placebo or 16,16 dimethyl prostaglandin E2 (dmPGE2) and incubated at 37 degrees C in either medium alone, medium containing 4.43 mM indomethacin or medium containing 8% ethanol. We assessed the viability of gland cells with fast green exclusion, release of lactate dehydrogenase (LDH) into the medium, and ultrastructural damage by scanning and transmission electron microscopy. Both indomethacin and ethanol significantly reduced the viability of placebo-pretreated glands, increased LDH release into the medium, and produced prominent ultrastructural damage. DmPGE2 significantly reduced both indomethacin and ethanol-induced injury, increased the number of viable cells, reduced LDH release, and diminished the extent of ultrastructural damage. These studies indicate that PG protection of gastric mucosal cells has a direct cellular action that is not limited to replacement of depleted endogenous PGs. PG protection in our experiments did not depend on PG's previously described systemic actions, such as protection of the microvessels, preservation of the mucosal blood flow, or stimulation of bicarbonate and mucus secretion.
Asunto(s)
16,16-Dimetilprostaglandina E2/farmacología , Etanol/antagonistas & inhibidores , Mucosa Gástrica/efectos de los fármacos , Indometacina/antagonistas & inhibidores , Prostaglandinas E Sintéticas/farmacología , Supervivencia Celular/efectos de los fármacos , Mucosa Gástrica/ultraestructura , L-Lactato Deshidrogenasa/metabolismo , Microscopía Electrónica , Microscopía Electrónica de RastreoRESUMEN
Phenylketonuria provides a human model for the study of the effect of phenylalanine on brain function. Although irreversible mental retardation is preventable through newborn diagnosis and dietary phenylalanine restriction, controversy exists regarding the effects of increased concentrations of phenylalanine in older patients. We have studied ten older, treated, phenylketonuric patients using a triple-blind, multiple trials, crossover design. Each patient was tested at the end of each of three 1-wk periods of high or low phenylalanine intakes. Tests included a repeatable battery of neuropsychological tests, analysis of plasma amino acids, and measurement of urine amino acids, phenyl organic acids, dopamine, and serotonin. In all 10 patients plasma phenylalanine rose (900-4,000 microM). In 9 of 10 patients there was an inverse relationship between plasma phenylalanine and urine dopamine excretion. When blood phenylalanine was elevated, these patients had prolonged performance times on neuropsychological tests of higher but not lower integrative function. Urinary serotonin fell during phenylalanine loading in six patients. The concentration of phenylacids in the urine was not proportional to the plasma phenylalanine at concentrations below 1.5 mM. In one patient, neither performance time nor dopamine excretion varied as blood phenylalanine rose or fell. We interpret these data as follows: blood phenylalanine above 1.3 mM impairs performance on neuropsychological tests of higher integrative function, this effect is reversible, and one mechanism may involve impaired biogenic amine synthesis.
Asunto(s)
Encéfalo/fisiología , Fenilalanina/sangre , Fenilcetonurias/sangre , Adolescente , Adulto , Transporte Biológico , Niño , Ensayos Clínicos como Asunto , Dopamina/orina , Femenino , Humanos , Túbulos Renales/metabolismo , Masculino , Pruebas Neuropsicológicas , Serotonina/orina , Triptófano/metabolismo , Tirosina/metabolismoRESUMEN
The incidence of syphilis, an infectious disease caused by Treponema pallidum, is low worldwide. The knowledge of its symptoms is however important, since the infectivity is high and therapy is comparatively easy. The first feature of an infection is the chancre, which is nearly always located in the genital region. In half of the infected patients after 8-12 weeks, if untreated, a generalisation takes place, during which the bacteria affect all organ systems. At first the skin diseases are most prominent; in long-term disease (late syphilis) symptoms of the central nervous system and the cardiovascular system become more relevant. In the chancre the infectious agent may be proven natively, but not in a culture. At about 3-6 weeks after infection specific serum antibodies may be proven with very sensitive and specific methods. Mainly the TPHA and FTA tests are used. These tests allow a reliable diagnosis to be made also in cases with ambiguous clinical features. The treatment of syphilis is performed by using parenteral depot penicillins for 14 days. It may also be applied as post-exposure prophylaxis. Specifics of the course have to be take into consideration in cases of coexisting HIV infections and neurosyphilis. The disease has a favourable prognosis, when treatment starts early enough.
Asunto(s)
Penicilinas/uso terapéutico , Serodiagnóstico de la Sífilis/métodos , Sífilis/diagnóstico , Sífilis/terapia , Antibacterianos/uso terapéutico , Alemania , Humanos , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina , Sífilis/clasificación , Sífilis/epidemiologíaRESUMEN
Purified reticulocyte lipoxygenase oxygenates the polyunsaturated phospholipids of sonified submitochondrial particles from bovine heart as measured by a burst of oxygen uptake. Over the frequency range of 0.5 to 100 MHz, the complex impedance of the submitochondrial particles as a function of the frequency before and after lipoxygenase attack was measured. From these data, the membrane capacity, the conductivity of the membrane and the conductivity inside the particles were calculated. Lipoxygenase action causes a 4-fold increase in the membrane capacity and a 2-fold increase in the membrane conductivity. Using the method of deformation of electric pulses, kinetic measurements were performed. In parallel to the changes of the passive electric properties, a partial inhibition of NADH oxidase and succinate oxidase was caused by the lipoxygenase attack. Oxygen uptake, changes of the passive electric properties and the inhibition of respiratory enzymes were prevented by lipoxygenase inhibitors. Owing to the high oxygen consumption produced by the lipoxygenase reaction, anaerobiosis was reached within the first 30 s in the closed chamber. Therefore, it must be concluded that the changes in passive electric properties and the inhibition of the respiratory enzymes are due to secondary anaerobic processes such as the hydroperoxidase reaction catalyzed by the lipoxygenase or a slow redistribution of peroxidized membrane lipids. The results are discussed in relation to the breakdown of mitochondria during the maturation process of red cells.
Asunto(s)
Lipooxigenasa/sangre , Mitocondrias Cardíacas/fisiología , Mitocondrias/fisiología , Reticulocitos/enzimología , Partículas Submitocóndricas/fisiología , Animales , Bovinos , Conductividad Eléctrica , Lipooxigenasa/farmacología , Matemática , Microscopía Electrónica , Mitocondrias Cardíacas/efectos de los fármacos , Mitocondrias Cardíacas/ultraestructura , Modelos Biológicos , Consumo de Oxígeno , Partículas Submitocóndricas/efectos de los fármacos , Partículas Submitocóndricas/ultraestructuraRESUMEN
Polymer networks are based on molecules which are covalently or physically connected in a three-dimensional network. In presence of an appropriate solvent these networks swell by solvent absorption to form gels. These gels, which are called hydrogels in case of water absorption, are able to change their volume by more than a hundred-fold. During the swelling or shrinking process the hydrogels perform a mechanical work. Their volume standardized working capacity can be ten-times larger than that of an electromagnet. Due to their simple design, miniaturisation properties, and their ability to realize many automatic sensor and actuator functions, smart hydrogels offer new solutions in biomedical technology.
Asunto(s)
Ingeniería Biomédica/instrumentación , Equipos y Suministros , Hidrogeles/química , Polímeros/química , Robótica/instrumentación , Transductores , Ingeniería Biomédica/métodos , Diseño de Equipo , Movimiento (Física) , Robótica/métodosRESUMEN
Guanylin and uroguanylin are peptides that stimulate membrane guanylate cyclases (GC) and regulate intestinal and renal function via cGMP. Complementary DNAs were isolated encoding opossum preproguanylin and a 279-amino acid portion of a receptor-guanylate cyclase expressed in opossum kidney (OK) cells (GC-OK). The tissue expression of messenger RNA transcripts for these signaling molecules were then compared. Northern and/or reverse transcription-PCR assays revealed that guanylin, uroguanylin, and GC-OK messenger RNAs are expressed in tissues within the digestive, renal, central nervous, reproductive, and lymphoid organ systems. Receptor autoradiography localized the receptors for uroguanylin and guanylin to renal proximal tubules and seminiferous tubules of testis. Synthetic guanylin and uroguanylin peptides activated the receptor-GCs in opossum kidney cortex and in cultured OK cells eliciting increased intracellular cGMP. Expression of agonist and receptor-GC signaling molecules provides a pathway for paracrine and/or autocrine regulation of cellular functions via cGMP in the digestive, renal, central nervous, reproductive, and lymphoid/immune organ systems. Uroguanylin also links the intestine and kidney in a potential endocrine axis that activates tubular receptor-GCs and influences renal function.
Asunto(s)
Hormonas Gastrointestinales , Péptidos/metabolismo , Transducción de Señal , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sistema Nervioso Central/metabolismo , ADN Complementario/genética , Sistema Digestivo/metabolismo , Genitales/metabolismo , Riñón/metabolismo , Sistema Linfático/metabolismo , Datos de Secuencia Molecular , Péptidos Natriuréticos , Zarigüeyas , Péptidos/genética , Precursores de Proteínas/genética , ARN Mensajero/metabolismoRESUMEN
Uroguanylin and guanylin are peptides isolated from urine and intestinal mucosa, which regulate cyclic GMP production in enterocytes by activating an apical membrane, receptor-guanylate cyclase. This study extended our previous findings, which showed that colonic mucosa of opossums contained uroguanylin and guanylin peptides, by purifying prouroguanylin and proguanylin from this tissue. Prouroguanylin and proguanylin coeluted from Sephadex G-75 gelfiltration columns with a similar molecular size between 6 and 12 kDa. Mass spectrometry indicated that proguanylin (approximately 8.7 kDa) had a 10% lower molecular mass than prouroguanylin (approximately 9.7 kDa). Isoelectric focusing separated prouroguanylin (pI approximately 4.5) from proguanylin (pI approximately 7.5). N-terminal sequence analysis of reverse phrase-HPLC purified prohormones revealed 13 amino acids in opossum proguanylin that shared 77-85% identity with human and rat proguanylin, but only 23% identity with opossum prouroguanylin. The N-terminal 19 residues obtained for opossum prouroguanylin shared 32-42% identity with rat and human proguanylin. Prouroguanylin and proguanylin were both inactive and required pretreatment with proteases to elicit cyclic GMP responses in T84 cells. V8 protease treatment of proguanylin liberated a bioactive, 16-amino acid form of guanylin. Chymotrypsin treatment activated prouroguanylin, but inactivated the bioactive peptide domain within proguanylin. In summary, colonic mucosa contains the bioactive peptide and inactive prohormone forms of uroguanylin and guanylin. Thus, after proteolytic processing of prouroguanylin and proguanylin, bioactive uroguanylin and guanylin could both function to regulate guanylate cyclase activity by autocrine and/or paracrine actions on enterocytes. Also, these peptide hormones are implicated in an intestinal-renal axis for the endocrine regulation of salt and water homeostasis.
Asunto(s)
Colon/química , Endopeptidasas/fisiología , Hormonas Gastrointestinales , Precursores de Proteínas/aislamiento & purificación , Precursores de Proteínas/metabolismo , Secuencia de Aminoácidos , Animales , Células Cultivadas , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Quimotripsina/farmacología , Colon/citología , Humanos , Mucosa Intestinal/química , Mucosa Intestinal/citología , Espectrometría de Masas , Datos de Secuencia Molecular , Zarigüeyas , Precursores de Proteínas/química , RatasRESUMEN
Guanylin and uroguanylin are small peptides containing two disulfide bonds that activate membrane guanylate cyclase-receptors in the intestine, kidney and other epithelia. Hybridization assays with a uroguanylin complementary DNA (cDNA) detected uroguanylin-like messenger RNAs (mRNAs) in the opossum spleen and testis, but these transcripts are larger than uroguanylin mRNAs. RT of RNA from spleen to produce cDNAs for amplification in the PCR followed by cloning and sequencing revealed a novel lymphoid-derived cDNA containing an open reading frame encoding a 109-amino acid polypeptide. This protein shares 84% and 40% of its residues with preprouroguanylin and preproguanylin, respectively. A 15-amino acid, uroguanylin-like peptide occurs at the COOH-terminus of the precursor polypeptide. However, this peptide is unique in having only three cysteine residues. We named the gene and its peptide product lymphoguanylin because the source of the first cDNA isolated was spleen and its mRNA is expressed in all of the lymphoid tissues tested. A 15-amino acid form of lymphoguanylin containing a single disulfide bond was synthesized that activates the guanylate cyclase receptors of human T84 intestinal and opossum kidney (OK) cells, although with less potency than uroguanylin and guanylin. Northern and/or RT-PCR assays detected lymphoguanylin mRNA transcripts in many tissues and organs of opossums, including those within the lymphoid/immune, cardiovascular/renal, reproductive, and central nervous organ systems. Lymphoguanylin joins guanylin and uroguanylin in a growing family of peptide agonists that activate transmembrane guanylate cyclase receptors, thus influencing target cell function via the intracellular second messenger, cGMP.
Asunto(s)
Clonación Molecular , Hormonas Gastrointestinales , Zarigüeyas/genética , Péptidos/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , GMP Cíclico/metabolismo , ADN Complementario/química , Mucosa Intestinal/metabolismo , Intestinos/efectos de los fármacos , Riñón/efectos de los fármacos , Riñón/metabolismo , Tejido Linfoide/química , Masculino , Datos de Secuencia Molecular , Péptidos Natriuréticos , Especificidad de Órganos , Péptidos/química , Péptidos/farmacología , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Homología de Secuencia , Bazo/química , Testículo/químicaRESUMEN
The occurrence and properties of PTH-related peptide (PTH-RP) in milk was investigated. PTH-RP was purified to homogeneity from human and bovine milk using heat and acid to precipitate milk proteins followed by ion exchange chromatography and reverse-phase HPLC. The peak of PTH-RP from HPLC was detected using a sensitive bone cell bioassay. A single band of peptide was detected on silver-stained polyacrylamide gels, which migrated as a 20-21-kDa macromolecule. PTH-RP isolated from either human or bovine milk had similar electrophoretic mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The partially purified bovine PTH-RP stimulated cAMP production in UMR106-01 and OK cell lines and elicited a concentration-dependent inhibition of sodium-dependent phosphate transport in OK cells. Incubation of milk extracts with an anti-PTH antiserum did not affect their bioactivity, whereas an antihuman PTH-RP 1-34 antiserum markedly reduced the cAMP response of UMR106-01 cells to the immunoabsorbed milk extracts. A PTH antagonist, norleu PTH 3-34, blocked the stimulation of cAMP production in UMR106-01 cells treated with milk extracts. PTH-RP immunoreactivity and bioactivity occurred in milk extracts of diverse animals from both eutherian and metatherian (marsupial) species. Porcine colostrum also had immunoreactive PTH-RP, although the levels were lower than the immunoreactive PTH-RP concentrations observed in milk samples collected at 7 and 14 days of lactation. Thus, a 20-21-KDa PTH-RP is secreted into milk where it could play a role in the development of suckling, newborn animals.
Asunto(s)
Leche Humana/análisis , Leche/análisis , Proteínas/aislamiento & purificación , Adenilil Ciclasas/metabolismo , Animales , Bioensayo , Western Blotting , Bovinos , Cromatografía Líquida de Alta Presión , Calostro/análisis , AMP Cíclico/biosíntesis , Activación Enzimática/efectos de los fármacos , Femenino , Cabras , Humanos , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Proteína Relacionada con la Hormona Paratiroidea , Fosfatos/metabolismo , Proteínas/farmacología , Porcinos , Células Tumorales CultivadasRESUMEN
Brunner's glands are unique to mammalian species and in eutherians are confined primarily to the submucosa of the proximal duodenum. In the majority of species examined, they begin at the gastrointestinal junction and extend for variable distances distally in the wall of the proximal small intestine. Ducts of individual glands empty either directly into the intestinal lumen or unite with overlying intestinal glands (crypts of Lieberkühn) dependent on the species. Secretory units of Brunner's glands consist of epithelial tubules that show frequent distal branchings. The secretory units, with the exception of those found in rabbits and horses, consist primarily of a mucin producing cell type. However, other cell types normally associated with the overlying intestinal epithelium may be encountered scattered within the secretory units reflecting the developmental origin of these glands. Secretion from Brunner's glands contributes to a layer of mucus that forms a slippery, viscoelastic gel that lubricates the mucosal lining of the proximal intestinal tract. The unique capacity of this mucus layer to protect delicate underlying epithelial surfaces is due primarily to the gel-forming properties of its glycoprotein molecules. Mucin glycoproteins produced by Brunner's glands consist primarily but not exclusively of O-linked oligosaccharides attached to the central protein core of the glycoprotein molecule. Human Brunner's glands produce class III mucin glycoproteins and are thought to be the product of mucin gene MUC6 which is assigned to chromosome 11 (11p15-11p15.5 chromosome region). In addition to mucin glycoproteins and a limited amount of bicarbonate, numerous additional factors (epidermal growth factor, trefoil peptides, bactericidal factors, proteinase inhibitors, and surface-active lipids) have been identified within the secretory product of Brunner's glands. These factors, incorporated into the mucus layer, guard against the degradation of this protective barrier and underlying mucosa by gastric acid, pancreatic enzymes, and other surface active agents associated with this region. Yet other factors produced by Brunner's glands function to provide active and passive immunological defense mechanisms, promote cellular proliferation and differentiation, as well as contribute factors that elevate the pH of luminal contents of this region by promoting secretion of the intestinal mucosa, pancreatic secretion and gall bladder contraction. Additional insights concerning the role of Brunner's glands in the mammalian gastrointestinal tract as well as their possible evolution in this class of vertebrates have been gained from a basic understanding of their pathobiology.
Asunto(s)
Glándulas Duodenales , Adaptación Fisiológica , Envejecimiento/fisiología , Animales , Glándulas Duodenales/anatomía & histología , Glándulas Duodenales/química , Glándulas Duodenales/patología , Glándulas Duodenales/fisiología , Duodeno/anatomía & histología , Duodeno/metabolismo , Duodeno/fisiología , Células Enteroendocrinas , Humanos , Mucosa Intestinal , Microscopía Electrónica , Mucinas/biosíntesis , Mucinas/genética , Neovascularización Fisiológica , Coloración y EtiquetadoRESUMEN
Plasma amino acid concentrations were measured and selected amino acid ratios were calculated in 12 normal adults and 12 adults heterozygous for phenylketonuria (PKU) ingesting a hamburger and milk shake meal providing 1 g protein/kg body wt. Plasma concentrations of all amino acids increased significantly over baseline after meal ingestion in both groups, reaching the highest mean values 3-5 h after meal ingestion. Plasma phenylalanine concentrations were significantly higher in heterozygous than in normal subjects both before and at all times after meal ingestion. The absolute increase in plasma phenylalanine concentration over baseline and the area under the plasma phenylalanine concentration-time curve were approximately twice as large in heterozygous as in normal subjects. However, the molar ratio of the plasma phenylalanine concentration to the sum of the plasma concentrations of the other large neutral amino acids did not increase significantly over baseline, but rather decreased.
Asunto(s)
Aminoácidos/sangre , Proteínas en la Dieta/metabolismo , Alimentos , Heterocigoto , Fenilcetonurias/sangre , Femenino , Humanos , Masculino , Fenilcetonurias/genéticaRESUMEN
It has long been assumed that the mucosa in areas of grossly 'healed' gastric or duodenal ulcers returns to normal, either spontaneously or after treatment. This assumption is based almost entirely upon visual, superficial examination by endoscopy. Few, if any, histological and ultrastructural studies examined the deeper mucosa in the areas of grossly healed ulcers. In several experimental studies, we analysed the development, evolution, and healing of acetic acid-induced gastric ulcers in rats and assessed the histological and ultrastructural features (structure and cellular composition) of the gastric mucosa in areas of grossly healed ulcers. The gastric mucosa of grossly 'healed' ulcers showed re-epithelialization of the mucosal surface at every study interval (2 weeks, 2, 3, and 4 months), but the subepithelial mucosa displayed prominent abnormalities. Two patterns of scarring were distinguished: (a) the mucosa in the area of healed ulcer was thinner (25-45% thinner than normal mucosa) with increased connective tissue and poor differentiation and/or degenerative changes in the glandular cells; and (b) the mucosa displayed a marked dilation of gastric glands with poor differentiation of the glandular cells and a reduction in the supportive microvascular network. It is theorized that these abnormalities could interfere with oxygenation, nutrient supply, and mucosal resistance and defence; therefore, they could be a basis for ulcer recurrence. These observations indicate that the quality of mucosal structural restoration rather than the speed of ulcer healing is the most important factor in determining risk of ulcer recurrence. The clinical relevance of these findings is supported by a preliminary study in which marked histological abnormalities were found in the subepithelial mucosa in patients with 'healed' duodenal ulcers.
Asunto(s)
Úlcera Gástrica/patología , Animales , Mucosa Gástrica/ultraestructura , RatasRESUMEN
OBJECTIVE: The objective of the current study was to test whether optimization of dose regimens for detecting focal liver lesions by computed tomography is possible by using the available time-density data of former studies published in the literature and a computer program so that the number of further clinical tests with the exclusive objective of optimizing injection schemes could be reduced. METHODS: Computed tomography enhancement data of the aorta and/or the liver obtained after injecting a conventional ionic and a nonionic contrast agent were used to calculate pharmacokinetic parameters and to simulate the time course of enhancement for a variety of different infusion regimens modifying contrast medium strength, dose, and injection rate. The study consisted of two parts. In the first part, mean relative enhancement curves of the aorta and of liver parenchyma (0 to 300 sec) using meglumine diatrizoate (306 mg iodine per mL, 300 mg iodine per kg) were taken from the literature and their values were approximated using the computer program TOPFIT. In the second part, equivalent data for iohexol including a total of three strengths (240, 300, and 350 mg iodine per kg) and doses from 30 to 45 grams of iodine were used. "Validation" of the simulation method was obtained, first by comparing measured and calculated maximum intensities and times to reach maximum and, second, by using one injection scheme for the simulation of a second and comparing the results with actually measured data. RESULTS: The computer program TOPFIT allowed for excellent curve fitting of the measured density values. The data obtained in the first part of the study showed that after a dose of 300 mg I/kg and a rate of 2 mL/sec maximal enhancement is achieved in the aorta after 30 seconds (approximately 100 HU) and in the liver after 50 seconds (approximately 30 HU). The higher the dose and the rate of infusion were, the higher was the enhancement. The difference in density between aorta and liver was proportional to the infusion rate approaching asymptotically approximately 90 HU at 8 mL/sec for a dose of 300 mg I/kg. Bi- or triphasic infusion schemes did not improve differences in enhancement. The curve fitting obtained in the second part of the study also confirmed the results reported in the literature. A "crossover" prediction of data was possible within the range of interindividual variations of pharmacokinetic parameters and thus validated the chosen approach of computer simulation. Furthermore, data sets selected randomly out of the simulation results could be used--within the limits of interindividual variability--to predict data determined in other clinical trials. CONCLUSION: The computer program TOPFIT appears useful for the optimization of time--density profiles in computed tomography. The number of further clinical studies with the objective of optimization could therefore possibly be reduced.