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S Martinez

Publications and source records attributed to S Martinez.

At least 73 records · Page 4Linked to original sources
PubMed1997

MR imaging of the elbow. An update.

MR imaging provides clinically useful information in assessing the elbow joint. Superior depiction of muscles, ligaments, and tendons as well as the ability to visualize nerves, bone marrow, and hyaline cartilage directly are advantages of MR imaging relative to conventional imaging techniques. These features of MR imaging may help to establish the cause of elbow pain by accurately depicting the presence and extent of bone and soft-tissue pathology. Ongoing improvements in surface coil design and newer pulse sequences have resulted in higher quality MR images of the elbow that can be obtained more rapidly. Recent clinical experience has shown the utility of MR imaging in detecting and characterizing disorders of the elbow in a noninvasive fashion.

Collateral Ligaments↗
PubMed1996

The avian inferior olive derives from the alar neuroepithelium of the rhombomeres 7 and 8: an analysis by using chick-quail chimeric embryos.

Homotopic and isochronic transplantation of the alar plate of the rhombomeres 7 and 8 was performed between chick and quail embryos at the stage of 10-14 somites. Analysis of the graft derivatives in 12-day-old chimeric embryos by means of the quail nucleolar marker showed that the ipsilateral inferior olive is formed from the transplanted neuroepithelium. In all embryos some cells originating from the graft were also found scattered throughout the contralateral inferior olive. The present results demonstrate that the inferior olive derives from the alar plate of the rhombomeres 7 and 8 and support the notion that a small contingent of inferior olivary neurones crosses the interolivary commissure during development.

Animals↗
PubMed1996

Midbrain development induced by FGF8 in the chick embryo.

Vertebrate midbrain development depends on an organizing centre located at the isthmus, a constriction in the embryonic mid/hindbrain region. Isthmic tissue grafts transform chick caudal forebrain into an ectopic midbrain that is the mirror image of the normal midbrain. Here we report that FGF8 protein has the same midbrain-inducing and polarizing effect as isthmic tissue. Moreover, FGF8 induces ectopic expression in the forebrain of genes normally expressed in the isthmus, suggesting that the ectopic midbrain forms under the influence of signals from a new 'isthmus-like' organizing centre induced in the forebrain. Because Fgf8 itself is expressed in the isthmus, our results identify FGF8 as an important signalling molecule in normal midbrain development.

Animals↗
PubMed1996

Expression patterns of two murine homologs of Drosophila single-minded suggest possible roles in embryonic patterning and in the pathogenesis of Down syndrome.

The single-minded (sim) gene encodes a transcriptional regulator that functions as a key determinant of central nervous system (CNS) midline development in Drosophila. We report here the identification of two murine homologs of sim, Sim1 and Sim2, whose products show a high degree of sequence conservation with Drosophila SIM in their amino-terminal halves, with each containing a basic helix-loop-helix domain as well as a PAS domain. Sim1 maps to the proximal region of mouse chromosome 10, whereas Sim2 maps to a portion of the distal end of chromosome 16 that is syntenic to the Down syndrome critical region of human chromosome 21. Recent exon-trapping studies have identified in the critical region several exons of a human sim homolog which appears to be the homolog of murine Sim2; this has led to the hypothesis that increased dosage of this sim homolog in cases of trisomy 21 might be a causal factor in the pathogenesis of Down syndrome. We have examined the expression patterns of the Sim genes during embryogenesis. Both genes are expressed in dynamic and selective fashion in specific neuromeric compartments of the developing forebrain, and the expression pattern of Sim2 provides evidence for early regionalization of the diencephalon prior to any overt morphological differentiation in this region. Outside the CNS, Sim1 is expressed in mesodermal and endodermal tissues, including developing somites, mesonephric duct, and foregut. Sim2 is expressed in facial and trunk cartilage, as well as trunk muscles. Both murine Sim genes are also expressed in the developing kidney. Our data suggest that the Sim genes play roles in directing the regionalization of tissues where they are expressed. Moreover, the expression pattern documented for Sim2 may provide insights into its potential roles in Down syndrome.

Amino Acid Sequence↗
PubMed1996

Otlx2, an Otx-related homeobox gene expressed in the pituitary gland and in a restricted pattern in the forebrain.

The vertebrate nervous system forms by the specification of, successively, neuroepithelial regions and cell groups. One of the proposed major histogenic steps is the subdivision of the neural tube in compartments along its caudorostral and dorsoventral axis. This event is reflected, and may be directed, by the restricted expression of many transcription factors. Here, we report on the isolation of a new homeobox gene of the paired superclass, Otlx2, whose early expression pattern in the mesencephalon and prosencephalon is congruent with proposed neuromeric models of brain morphogenesis. In addition, its late embryonic and postnatal expression, in clear continuity with the earlier pattern, suggests a role in the neuronal differentiation and the histogenesis of several prosencephalic and mesencephalic areas. Finally, Otlx2 is expressed from the earliest morphogenetic events in the Rathke's pouch, the anlage of the adenohypophysis, an expression site shared by a very close homologue, Otlx1/Ptx1/P-Otx.

Amino Acid Sequence↗
PubMed1996

C-Fos expression in trigeminal nucleus neurons after chemical irritation of the cornea: reduction by selective blockade of nociceptor chemosensitivity.

The distribution and number of trigeminal brainstem and higher order sensory neurons expressing the protein product of the proto-oncogene c-fos after noxious stimulation of the cornea was studied in the rat using immunocytochemistry. The possibility that attenuation of nociceptive messages from the cornea by diltiazem reduced Fos-like immunoreactivity of spinal trigeminal neurons was also examined. A group of animals were killed 2-3 h after corneal stimulation. One cornea was stimulated with: a drop of 10 mM acetic acid; with acid plus mechanical scratching of the corneal epithelium; or with a drop of saline of 56 degrees C. Half of the animals treated with acid had been pretreated ipsilaterally with topical diltiazem (10 mM). Control rats received either saline in one eye or no treatment. Another group of animals were killed 7-8 h after stimulation with acetic acid. Fos-like immunoreactive neurons were counted in serial brainstem sections using an anti-Fos primary antiserum and processed according to the avidin-biotin complex method. In rats killed 2-3 h after corneal stimulation with acid, heat, or acid plus mechanical injury, labelled neurons were found in laminae I and II of the intermediate zone between caudalis and interpolaris subnuclei of the ipsilateral spinal trigeminal nucleus and, in a reduced number, in the symmetrical zones of the contralateral side. In animals stimulated with noxious heat or combined mechanical and chemical injury, a few scattered cells were also labelled in the ipsilateral junction between the cervical spinal cord and the caudalmost part of the trigeminal subnucleus caudalis. In rats killed 7 h after stimulation with acid, stained neurons were observed in the same areas of the trigeminal nucleus as in rats killed at shorter times, but in lower numbers; in these animals, no immunoreactive cells were found in deeper laminae or in higher sensory relay nuclei. Pretreatment with diltiazem significantly reduced the number of cells of the spinal trigeminal nucleus labelled after corneal stimulation with acid. The results indicate that brief noxious stimulation of the cornea evoke expression of c-Fos in neurons of the spinal trigeminal complex. Diminution by diltiazem of the number of immunoreactive neurons activated by corneal irritation suggests that this drug, by reducing chemosensitivity of nociceptive terminals, decreases nociceptive inflow to central nervous structures involved in ocular pain perception.

Animals↗
PubMed1996

Multifocal vascular lesions of bone: imaging characteristics.

OBJECTIVE: Multifocal vascular processes which arise in bone are a very inhomogeneous class of diseases. Four of these processes are derived from endothelial precursors, however, and share a similar radiographic spectrum. These four entities are reviewed in order to clarify their imaging patterns and the diagnostic utility of imaging modalities. METHODS: Eight cases of cystic angiomatosis, multifocal hemangioma, hemangioendothelioma and angiosarcoma presenting to a tertiary referral center over a 7-year period were reviewed. The medical literature was also reviewed for information concerning the imaging of these processes. RESULTS: All four diseases produced radiolucent defects on plain radiographs with variable margination reflecting the aggressiveness of the lesions. Computed tomography was used to examine five patients and provided supportive, though generally non-diagnostic, information in the five cases in which it was performed. Radionuclide bone scintigraphy, as reported in the literature, underestimated the extent of skeletal involvement in all eight cases, though some lesions were identified. Radionuclide imaging with labeled red blood cells, performed in three cases, did not add any information, which is contrary to some reports in the literature. Magnetic resonance imaging proved the most sensitive for identifying lesions, although the imaging characteristics were not diagnostic. CONCLUSIONS: Plain radiographs are the mainstay for imaging multifocal endothelial processes. Radiographs provide information on aggressiveness, multifocality and distribution of lesions. Computed tomography provides similar information. Magnetic resonance imaging often detects additional lesions. The insensitivity of radionuclide bone scintigraphy is surprising. Reports of unique deposition of radionuclide in tagged red blood cell scanning has been reported to support the diagnosis of vascular lesions, but it did not do so in these cases.

Adolescent↗
PubMed1996

Pain measurement in elders with chronic low back pain: traditional and alternative approaches.

Pain evaluation typically relies upon the use of self-report instruments. The validity of these tools is questionable in many older adults, however, particularly those with cognitive impairment. Rating of pain behavior (e.g. grimacing, sighing) by an objective observer represents an alternative pain assessment strategy which has been validated in subjects of heterogeneous ages. The purpose of this study was to examine, in a group of community-dwelling elderly with low back pain and lumbosacral osteoarthritis, the concurrent validity of observational pain behavior rating techniques as compared with self-report instruments and the degree to which pain and pain behavior relate to disability. Thirty-nine cognitively intact subjects, age > 65 years, without depression, other sources of pain, or other known spinal pathology underwent the following measures: (1) pain self-report using the verbal 0-10 scale, vertical verbal descriptor scale, Arthritis Impact Measurement Scales and McGill Pain Questionnaire; (2) pain behavior was sampled during two protocols, one, identical to that used by Keefe and Block (Behav. Ther., 13 (1982) 363-375), that required subjects to sit, stand, walk, and recline for 1-2 minute periods (which we have labelled the traditional protocol), and a second, more demanding protocol that was designed to simulate activities of daily living that place a premium on axial movement (the 'ADL' protocol); (3) disability was assessed using the Roland questionnaire, a 6 month global disability question and the Jette Functional Status Index; and (4) radiographic evaluation of the lumbosacral spine; osteoarthritis was quantitated using a previously validated scoring system. Interrelationships among pain, pain behavior and disability measures were tested using canonical correlations. Self-reported pain was associated with pain behavior frequency; the association was stronger when the ADL protocol was used, as compared with the traditional protocol. The association between pain and disability was modestly strong with both self-report instruments and pain behavior observation when the ADL protocol was used, but not when the traditional protocol was used. Our findings suggest that pain behavior observation is a valid assessment tool in the elderly. In addition, it seems that observation of elders during performance of activities of daily living may be a more sensitive and valid way of assessing pain behavior than observing pain behavior during sitting, walking, standing, or reclining.

Activities of Daily Living↗
PubMed1996

Acquisition of services recommended by a multidisciplinary medical diagnostic team for children under three years of age evaluated for developmental delays.

After multidisciplinary medical diagnostic teams evaluate children with developmental delays, they recommend to parents that they seek specific services, but the team rarely knows which services are obtained. We sought to determine which services pursued by the parents were actually acquired and to determine if there were barriers to the acquisition of services. In a diagnostic clinic located in a teaching hospital in an urban setting, we evaluated 92 children less than 3 years of age mainly from an inner city population. At a family conference, the parents had indicated an interest in pursuing an average of 1.87 +/- 1.34 social services, 1.70 +/- 1.32 educational services, and 3.61 +/- 2.31 medical services recommended by the team. Four months after the family conference, the actual services obtained by families included 38.5% of the social services, 70.87% of the educational services, and 71.36% of the medical services. Significantly fewer social services were obtained than educational and medical services.

Chicago↗
PubMed1996

A possible structural determinant of selectivity of boldine and derivatives for the alpha 1A-adrenoceptor subtype.

1. The selectivity of action of boldine and the related aporphine alkaloids, predicentrine (9-O-methylboldine) and glaucine (2,9-O-dimethylboldine) and alpha 1-adrenoceptor subtypes was studied by examining [3H]-prazosin competition binding in rat cerebral cortex. WB 4101 and benoxathian were used as selective alpha 1A-adrenoceptor antagonists. 2. In the competition experiments [3H]-prazosin (0.2 nM) binding was inhibited by WB 4101 and benoxathian. The inhibition curves displayed shallow slopes which could be subdivided into high and low affinity components (pKi = 9.92 and 8.29 for WB 4101, 9.35 and 7.94 for benoxathian). The two antagonists recognized approximately 37% of the sites with high affinity from among the total [3H]-prazosin specific binding sites. 3. Boldine, predicentrine and glaucine also competed for [3H]-prazosin (0.2 nM) binding with shallow and biphasic curves recognizing 30-40% of the sites with high affinity. Drug affinities (pKi) at the high and low affinity sites were, 8.31 and 6.50, respectively, for boldine, 8.13 and 6.39 for predicentrine, and 7.12 and 5.92 for glaucine. The relative order of selectivity for alpha 1A-adrenoceptors was boldine (70 fold alpha 1A-selective) = predicentrine (60 fold, alpha 1A-selective) > glaucine (15 fold, alpha 1A-selective). 4. Pretreatment of rat cerebral cortex membranes with chloroethylclonidine (CEC, 10 microM) for 30 min at 37 degrees C followed by thorough washing out reduced specific [3H]-prazosin binding by approximately 70%. The CEC-insensitive [3H]-prazosin binding was inhibited by boldine monophasically (Hill slope = 0.93) with a single pKi value (7.76). 5. These results suggest that whereas the aporphine structure shared by these alkaloids is responsible for their selectively of action for the alpha 1A-adrenoceptor subtype in rat cerebral cortex, defined functional groups, namely the 2-hydroxy function, induces a significant increase in alpha 1A-subtype selectivity and affinity.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1996

Uremic leontiasis ossea: "bighead" disease in humans? Radiologic, clinical, and pathologic features.

PURPOSE: To describe the clinical, radiologic, and pathologic findings in patients with uremic leontiasis ossea (ULO). MATERIALS AND METHODS: Five patients with renal osteodystrophy developed marked hyperostosis of the facial and cranial bones. Radiologic studies included plain radiography of the skull (n = 5), computed tomography with three-dimensional reconstruction (n = 4), magnetic resonance imaging (n = 3), and fluorine-18 sodium fluoride positron emission tomography (PET) (n = 1). Specimens from bone biopsies (three patients) were examined. RESULTS: Skull and facial alterations were remarkably similar. Numerous nodules of varying attenuation and signal intensity in the widened diploic space suggested brown tumors in different stages of evolution. Biochemical data and PET findings enabled confirmation of markedly increased bone turnover. Bone specimens demonstrated severe osteitis fibrosa. After parathyroidectomy, facial changes in all patients stabilized or improved mildly. CONCLUSION: A similar entity in animals, "bighead" disease, which results from nutritional and uremic secondary hyperparathyroidism, may provide a useful animal model for ULO in humans. Mild forms of this entity may be more common than the scarcity of previous reports suggests.

Adult↗
PubMed1995

Null mutation of Dlx-2 results in abnormal morphogenesis of proximal first and second branchial arch derivatives and abnormal differentiation in the forebrain.

Genetic analysis of the development and evolution of the vertebrate head is at a primitive stage. Many homeo box genes, including the Distal-less family, are potential regulators of head development. To determine the function of Dlx-2, we generated a null mutation in mice using gene targeting. In homozygous mutants, differentiation within the forebrain is abnormal and the fate of a subset of cranial neural crest cells is respecified. The latter causes abnormal morphogenesis of the skeletal elements derived from the proximal parts of the first and second branchial arches. We hypothesize that the affected skull bones from the first arch have undergone a transformation into structures similar to those found in reptiles. These results show that Dlx-2 controls development of the branchial arches and the forebrain and suggests its role in craniofacial evolution.

Animals↗
PubMed1995

Expression of neuronal nitric oxide synthase corresponds to regions of selective vulnerability to hypoxia-ischaemia in the developing rat brain.

Nitric oxide (NO) has been implicated in the pathogenesis of brain injury from hypoxia-ischaemia. In the brain, the enzyme responsible for NO synthesis is neuronal nitric oxide synthase (nNOS). Using in situ hybridization, immunohistochemistry and NADPH diaphorase histochemistry, we examined the spatial and temporal expression of nNOS during development of the rat brain to determine whether the expression of nNOS delineates the areas of the brain that are selectively vulnerable to hypoxic-ischaemia injury. The expression of nNOS was localized to discrete areas of the brain. nNOS could be detected in the developing forebrain in the 10-day-old embryo (E10). From E14 to E18, the highest level of expression was in the cortical plate, where the majority of neurons were positive. However, this expression diminished with time; in the adult there were only a few nNOS-positive neurones in the deep layers of the cortex. Expression of nNOS was not detected prenatally in the basal ganglia. There was transient high-level expression during the first postnatal week. Thereafter, the basal ganglia exhibited the adult pattern of expression. Expression of nNOS could be detected in the hippocampus at E16. This expression remained constant with regional localization in layers CA1 and CA3 in the adult. Similarly, nNOS expression in the developing cerebellum was observed only after birth. From the first day after birth (P1) to P6, expression was limited to the molecular cell layer. As the cerebellum matured, nNOS expression could be detected in the inner granular layer. By P21, the adult distribution of nNOS expression was observed. All regions expressing nNOS mRNA also demonstrated nNOS protein expression and NADPH diaphorase catalytic activity. Our results demonstrate that nNOS expression in the developing brain correlates with regions of selective vulnerability to hypoxic-ischaemic injury, and, therefore, supports a role for NO in hypoxic-ischaemic injury in the developing brain.

Animals↗
PubMed1995

Functional and mobility impairments associated with Paget's disease of bone.

OBJECTIVE: To determine if patients with Paget's disease of bone involving the tibia, femur, and/or acetabular portion of the ilium had more impairments in function and mobility than age- and sex-matched control subjects. PATIENTS AND METHODS: A case control study with Paget's disease patients selected from a center for bone disease at a tertiary medical center; control subjects were volunteers from the Duke University Aging Center subject registry. Demographic characteristics, physical examination and serum alkaline phosphatase levels were obtained. Radiographs of the pelvis and lower extremities were evaluated by a radiologist. All participants completed a Functional Status Questionnaire (FSQ). Mobility measures included mobility skills protocol, 10-foot walk time, 360-degree turn left (number of steps), and 6-minute walk distance. RESULTS: The 12 Paget's disease patients were no different in age (70.7 +/- 6.2 years) than the 12 control subjects (69.5 +/- 6.2 years). Serum alkaline phosphatase levels were elevated in Paget's patients (539 +/- 530 IU/L), and normal in control subjects (85 +/- 17 IU/L). In addition to Paget's disease, radiographs showed joint space loss in joints proximate to the diseased bone. On the FSQ scales Paget's disease patients had significantly lower scores in basic activities of daily living (P < .05), instrumental activities of daily living (P < .001), and social activity than control subjects (P < .05). There was no difference between the groups on scales measuring mental health and quality of social interaction. On mobility measurements, Paget's disease patients showed significant impairments when compared with control subjects: mobility skills protocol score (22.5 +/- 2.5 vs 25.6 +/- 0.7, P < .001); 10-foot walk (3.96 +/- 1.3 vs 2.55 +/- 0.5 seconds, P < .001); 360 degree turn left (8.0 +/- 1.0 vs 5.9 +/- 0.6 steps, P < .001); and 6-minute walk (342.0 +/- 108.5 vs 519.4 +/- 100 meters, P < .001). CONCLUSION: When compared with control subjects, patients who have Paget's disease of bone involving the tibia, femur, or acetabular portion of the ilium have clinically and statistically significant functional and mobility impairments compared to age- and gender-matched controls.

Activities of Daily Living↗
PubMed1995

Pyomyositis: characteristics at CT and MR imaging.

PURPOSE: To establish imaging criteria for pyomyositis (PM). MATERIALS AND METHODS: Twenty-seven computed tomographic (CT) scans and 11 magnetic resonance (MR) images obtained in 32 patients with PM were reviewed. Images in 10 patients with PM and 16 with soft-tissue masses were evaluated blindly. RESULTS: At CT, all 27 patients had muscle enlargement with heterogeneous attenuation; 26 patients had a focal fluid collection, with rim enhancement in all 18 patients who underwent contrast material-enhanced CT. Twenty-four patients had cellulitis. At MR imaging, all 11 patients had both a subtle increase in signal intensity in the affected muscle(s) on T1-weighted images and cellulitis. Nine patients had a focal fluid collection, which had high signal intensity and a hypointense rim on T2-weighted images. In six patients, a rim of increased signal intensity was seen around the collection on T1-weighted images. Six gadolinium-enhanced examinations demonstrated rim enhancement. Eight patients had fluid in the distal joint. All patients with PM were correctly identified when evaluated with the control subjects; however, there were four false-positive results. CONCLUSION: CT and MR imaging can help characterize changes that are suspicious for PM.

Adolescent↗
PubMed1995

Longitudinal organization of the anterior neural plate and neural tube.

Over the last century, several morphological models of forebrain organization have been proposed that hypothesize alternative topological solutions for the relationships of the histogenic primordia. Central to all of these models are their definitions of the longitudinal axis and the longitudinal organization of the neural plate and neural tube. To understand the longitudinal organization of the anterior brain, we have sought to identify molecular properties that are continuous along the entire longitudinal axis of the embryonic CNS. In this essay, we describe studies of the expression of several genes in the mouse between 7.5 (presomite stage) and 10.5 days post coitum (dpc) that provide evidence for the trajectory of the anterior-posterior axis and the longitudinal organization of the anterior CNS. Specifically, we report that the expression of noggin, sonic hedgehog and Nkx-2.2 define longitudinal columns of cells that are present along the entire CNS axis. Within the forebrain, the expression of these genes, as well as that of Nkx-2.1 and BF-1, are in distinct longitudinal regions in the neural plate and tube. We demonstrate that the earliest longitudinal axon pathways of the forebrain are spatially correlated with the longitudinal domain defined by Nkx-2.2. Finally, expression of the former genes, and Otx-1 and Emx-2, suggests that the cephalic neural plate is organized into molecularly distinct domains delimited by longitudinal and transverse borders; these results provide a foundation for defining the mechanisms that pattern the neural plate.

Animals↗