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J Montalvo

Publications and source records attributed to J Montalvo.

At least 19 recordsLinked to original sources
PubMed2000

Differential regulation of mammalian brain-specific proline transporter by calcium and calcium-dependent protein kinases.

1. This study examined the role of [Ca2+]I and Ca(2+)-dependent kinases in the modulation of high-affinity, mammalian brain-specific L-proline transporter (PROT). 2. beta-PMA (phorbol 12-myristate 13-acetate), an activator of protein kinase C (PKC), inhibits PRO uptake, and bisindolymalemide I (BIM), a potent PKC inhibitor, prevents beta-PMA inhibition. Down-regulation of PKC by chronic treatment with beta-PMA enhances PROT function indicating PROT regulation by tonic activity of PKC. 3. Thapsigargin, which increases [Ca2+]I levels by inhibiting Ca(2+)-ATPase, inhibits PROT and exhibits additive inhibition when co-treated with beta-PMA. KN-62, a Ca2+/calmodulin-dependent kinase II (CaMK II) inhibitor, but not BIM (a PKC inhibitor) prevents the inhibition by thapsigargin. These data suggest that PKC and CaMK II modulate PROT and that thapsigargin mediates its effect via CaMK II. 4. Thapsigargin raises [Ca2+]I and increases PRO-induced current on a second time scale, whereas the inhibitory effect of thapsigargin occurs only after 10 min of treatment. These data suggest that Ca2+ differentially regulate PROT: Ca2+ initially enhances PRO transport but eventually inhibits transport function through CaMK II pathway. 5. Ca(2+)-induced stimulation exemplifies the acute regulation of a neurotransmitter transporter, which may play a critical role in the profile of neurotransmitters during synaptic transmission.

Amino Acid Transport Systems, Neutral↗
PubMed1999

Identification of caveolae and caveolin in C6 glioma cells.

Caveolae (CAV) constitute a novel subcellular transport vesicle that has received special attention based on its proven and postulated participation in transcytosis, potocytosis, and in cell signaling events. One of the principal components of CAV are caveolin protein isoforms. Here, we have undertaken the immunochemical identification of CAV and the known caveolin isoforms (1alpha, 1beta, 2 and 3) in cultured rat C6 glioma cells. Immunoblot analysis revealed that particulate fractions from rat C6 glioma cells express caveolin-1 and caveolin-2. The relative detergent-insolubility of these caveolin isoforms was also determined by Western blot analysis. Indirect immunofluorescence analysis with caveolin-1 and -2 antibodies revealed staining patterns typical of CAV's known subcellular distribution and localization. For both caveolin isoforms immunocytochemical staining was characterized by intensely fluorescent puncta throughout the cytoplasm and diffuse micropatches at the level of the plasmalemma. Perinuclear staining was also detected, consistent and suggestive of caveolin's localization in the trans Golgi region. The caveolin-1 and -2 immunoreactivity seen in Western blots and immunocytochemically is related to structurally relevant CAV as supported by the isolation of caveolin-enriched membrane complexes using two different methods. Light-density, Triton X-100-insoluble caveolin-1- and caveolin-2-enriched fractions were obtained after fractionation of rat C6 glioma cells and their separation over 5-40% discontinuous sucrose-density gradients. Similar fractions were obtained using a detergent-free, sodium carbonate-based fractionation method. These results further support the localization of CAV and caveolins in glial cells. In addition, they demonstrate that cultured C6 glioma cells can be useful as a model system to study the role of CAV and caveolins in subcellular transport and signal transduction events in glial cells and the brain.

Animals↗
PubMed1998

Expanded indications for the treatment of postcatheterization femoral pseudoaneurysms with ultrasound-guided compression.

BACKGROUND: The purpose of this study was to define the factors that predict successful ultrasound-guided compression repair (UGCR) of postcatheterization femoral pseudoaneurysms (PA) and to determine risks for recurrence, the most appropriate follow-up, and the optimal management of compression failures and recurrences. METHODS: A retrospective chart review was made. RESULTS: UGCR thrombosed 52 of 60 PA (87%). Predictors of compression failure were PA size of 8 cm and an associated arteriovenous fistula (AVF). AVF was the only predictor of recurrence. All seven recurrences (13%) were discovered on the first follow-up scan. Four were thrombosed with additional UGCR. Late rescanning after a mean of 264 days identified no recurrences. Four anticoagulated patients failed initial UGCR but were thrombosed in another session when their anticoagulation was briefly reversed. CONCLUSIONS: UGCR should be the initial management of PA because it is safe, effective, and durable. Temporary discontinuation of anticoagulation and multiple prolonged compression sessions may help treat recalcitrant cases. One follow-up scan is adequate for most patients. Recurrences should be initially treated with repeat UGCR.

Adult↗
PubMed1995

Early prediction of stroke severity. Role of the erythrocyte sedimentation rate.

BACKGROUND AND PURPOSE: Early predictors of functional outcome after stroke are necessary for better planning of treatment and care. METHODS: We evaluated prospectively early clinical predictors of short-term functional outcome in a group of patients with ischemic cerebral infarction and explored whether the intensity of the acute-phase response provided further information concerning the short-term functional outcome. We evaluated a group of 208 ischemic stroke patients using the Mathew scale at entry. All patients had neuroimaging studies and routine blood tests, including erythrocyte sedimentation rate (ESR), within 72 hours from clinical onset. At discharge, functional outcome was graded according to a Stroke Outcome Scale. RESULTS: Larger infarcts, more embolic infarcts, and fewer lacunar infarcts were observed in the poor-outcome group. Vascular risk factors, radiological findings not related to the index stroke, time to admission, and treatment were similar in the two outcome groups. Variables with statistically significant differences between outcome groups included the following: age > 65 years, female sex, admission Mathew score < 75, worsening at clinical presentation, infarct volume > 6 cm3, complicating infections, fasting glucose > 110 mg, nonfasting glucose > 130 mg, and elevated ESR. With stepwise logistic regression analysis, Mathew score on admission, infarct volume, mode of clinical presentation, and ESR remained in the predictive model of stroke outcome, with a sensitivity and specificity of 89.91% and 85.71%, respectively. After removing the computed tomographic information from the model the same variables remained, with a sensitivity and specificity of 83.05% and 94.29%, respectively. CONCLUSIONS: Infarct size and clinical severity on admission are the stronger predictors of short-term functional outcome. Mode of clinical presentation, clinical evolution during the first day of stroke, and ESR are also independent predictors of short-term stroke outcome. These findings might be indicative of an inadequate collateral profile and/or a more pronounced prothrombotic state.

Adult↗
PubMed1992

Long-term results of venous reconstruction after vascular trauma in civilian practice.

The natural history of venous reconstruction (VR) in terms of patency and clinical outcome after vascular trauma has not been well documented. This study consists of 32 patients who had VR performed for extremity vascular trauma and were available for long-term assessment (mean follow-up time 49 months, range 6 to 108 months). The types of repair performed were as follows: lateral venorrhaphy (simple repair) (56%), interposition grafting (22%), patch repair (12.5%), and end-to-end repair (9.5%). Seventeen patients underwent venography after the operation with documentation of repair patency in eight patients (46%) and thrombosis in nine (54%). Only two patients had significant clinical edema at follow-up examination. Noninvasive venous evaluation consisted of Doppler ultrasonography, impedance plethysmography, photoplethysmography, and color-flow duplex scanning (CFDS). The photoplethysmography-derived venous refilling time of the injured extremity was 34.9 +/- 16.2 seconds whereas that of the contralateral noninjured extremity was 36.8 +/- 16.1 seconds (p = 0.5). Based on standard criteria for CFDS, 90% of VRs were patent. Eight repairs that were patent in the early postoperative period remained patent on CFDS. Of the nine repairs with early thrombosis, eight were assessed as patent on follow-up CFDS. In conclusion, VR is a durable surgical procedure associated with minimal morbidity, good long-term patency, and preservation of venous competence. The natural history of thrombosed VRs appears to be one of thrombus absorption with recanalization.

Adolescent↗
PubMed1991

A nine-year experience with crossover femoro-femoro-popliteal sequential bypass.

Multisegmental arterial occlusive disease may require a combined inflow and outflow procedure for optimal treatment of limb ischemia. Twenty-one patients with unilateral iliac artery stenosis or occlusion and ipsilateral superficial femoral artery occlusion underwent crossover femoro-femoro-popliteal sequential bypass during a 9-year period. Seventeen operations were for limb salvage. Patency rates were determined separately for each segment of the bypass. Primary patency rates for the femoro-femoral segment were 89%, 83%, and 57% at 1, 2, and 5 years, respectively. Primary patency rates for the femoro-popliteal segments were 68%, 62%, and 40% at 1, 2, and 5 years, respectively. Limb salvage rates were 100%, 90%, and 77% at 1, 2, and 5 years, respectively. This experience indicates that femoro-femoro-popliteal bypass is an effective treatment in selected patients with severe ischemia due to combined iliac artery and superficial femoral artery disease.

Aged↗
PubMed1989

Identification of features of metaplastic cells in sputum for the detection of squamous-cell carcinoma of the lung.

Digitized images of 1,556 squamous metaplastic cells from the sputum of 15 patients with confirmed squamous-cell carcinoma of the lung and 13 subjects without apparent neoplasia were analyzed to determine if features existed within these relatively normal cells that could be used to differentiate between the two populations. Results indicate that such marker features do exist. A cross-validation study using an additional 465 cells confirmed the conclusion that squamous metaplastic cells from patients with squamous-cell carcinoma of the lung do differ from those of subjects without cancer. While such marker features alone are not reliable enough to assist pathologists in the diagnosis of squamous-cell carcinoma of the lung, they might, in sufficient numbers, be used to identify patients for whom follow-up testing would be advised.

Biomarkers, Tumor↗
PubMed1989

Topical mupirocin treatment of impetigo is equal to oral erythromycin therapy.

Topical antimicrobial therapy has not been effective in the past against cutaneous bacterial infections. In this study, a new topical antibiotic ointment, mupirocin, was compared with oral erythromycin ethylsuccinate in the treatment of impetigo. Seventy-five patients clinically diagnosed as having impetigo and with positive cultures of Staphylococcus aureus, Streptococcus pyogenes, or both were examined in an investigator-blinded study. Patients used topical mupirocin applied three times daily or the usual oral dose of erythromycin ethylsuccinate (30 to 50 mg/kg per day). Patients' lesions were examined clinically and cultured bacteriologically on days 0, 3, and 8, and 1 week after treatment. Susceptibility testing was performed on pathogens isolated to determine antibiotic resistance. Mupirocin treatment produced similar clinical results to oral erythromycin and was superior in the eradication of S aureus, including antibiotic-resistant S aureus. These results show topical mupirocin to be a safe and effective alternative to oral antibiotic therapy in the treatment of impetigo.

Administration, Oral↗
PubMed1988

Chronic malnutrition, dental caries, and tooth exfoliation in Peruvian children aged 3-9 years.

A cross-sectional evaluation of dental caries in primary teeth and nutritional status was conducted involving 285 Peruvian children from low socioeconomic conditions aged 3-9 y. Forty-nine percent of the children were found to be chronically malnourished (stunted) whereas acute malnutrition (wasting) was infrequent (2%). Stunted children showed a delayed exfoliation of primary teeth. The caries prevalence curve as a function of age (ie, a plot of decayed, extracted, and filled teeth vs age) was found to be shifted to the right by approximately 15 mo in stunted children as compared with well-nourished children. Children aged 7-9 y with stunted growth showed a significantly higher percentage of carious teeth than did well-nourished children of the same age (40 and 29%, respectively; p less than 0.005). Nutritional deficits that lead to chronic malnutrition not only may affect tooth exfoliation but also appear to render the primary teeth more susceptible to caries attack later in life.

Child↗
PubMed1988

Abnormalities of immunoregulation in Kawasaki syndrome.

The object of our investigation was to determine the immunoregulatory abnormalities in 48 children with Kawasaki syndrome. We demonstrated a global lymphocytosis with marked expansion of the B cell subset. Despite an increase in B cell numbers, there was a decrease in in vitro immunoglobulin production in response to pokeweed mitogen and hydrocortisone stimulation. These abnormalities correlated with a marked increase in the percentage of CD4+2H4+ (CD4+CD45R+) T cells, a T cell subset thought to be responsible for inducing suppression. Other abnormalities of T cells include cutaneous and in vitro anergy and evidence of T cell activation. Our results suggest that the B cell abnormalities seen in Kawasaki syndrome may be partially explained by defects in T cell immunoregulation.

Antigens, Differentiation↗
PubMed1984

Precision cell location and relocation techniques. An application for cell image analysis.

Two methods for precise cell location and relocation were developed at the Cell Image Analysis Laboratory, NASA, to increase the efficiency of the cell image acquisition process. The first method uses a Zeiss Zonax with a 10 micron scanning stage and automatically records cell coordinates on 5.25-inch floppy disks. The second method uses a Digital Positioning Device with a 10 micron scanning stage, and the cell coordinates displayed on light-emitting diodes (LEDs) are recorded manually. Because of its superior speed and automation, the Zonax was selected as the method of choice. By using a Zonax for off-line cell location and another Zonax for on-line cell relocation, more than three times the number of digitized images were collected in ten months than in the previous three years. Other beneficial applications of the cell location and relocation methods were realized in photomicrography, data base verification and cytopathology.

Computers↗
PubMed1983

Brain tumors in children. Results of treatment in 138 patients.

Tumors of the nervous system are the third most common malignant disease in Cuban children, after leukemia and lymphoma. In 138 patients with the diagnosis of brain tumor results of treatment by surgery and radiation were studied. The survival rate at 1, 3 and 5 years was 50, 40 and 37.6%. The best results were achieved in astrocytomas, mid grain and brain stem tumors and oligodendrogliomas.

Astrocytoma↗
PubMed1983

Classification of bronchial epithelial atypias by the atypia status index.

The atypia status index (ASI) is a categorization method of classifying digitized images of atypical bronchial epithelial cells in sputum. The ASI is defined as a linear composite of features linearly related to atypia stage. Over 200 features were examined for more than 3,000 cells that had been classified by atypia stage (squamous metaplasia, mild, moderate or severe atypia and malignant) and staining characteristic (orangeophilia and nonorangeophilia). We reduced the number of features by using a selection process to minimize redundancy. The feature weights were optimized via a least-squares procedure. The 14 features selected accounted for over 60% of the variation of atypia stage and produced ASI values that were within one atypia stage of the criterion classification for over 90% of the cells. The results are consistent with the hypothesis of a progressive pattern in bronchial epithelial atypia and indicate the feasibility of using image analysis for mass screening of premalignant atypias in sputum from subjects considered to be at high risk for lung cancer.

Adult↗
PubMed1980

Complications from irradiation of carcinoma of the uterine cervix.

The types and frequency of complications in 2248 patients irradiated for carcinoma of the cervix using different techniques are reported. Proctitis was the most frequent complication. Severe complications, such as fistulas, ureteral stenosis with hydronephrosis, enterocolitis, sigmoiditis, intestinal obstruction and skin necrosis occurred in 81 patients (3.6%). Only 36 patients (1.6%) developed fistulas.

Brachytherapy↗