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Biomedical subjects

M Ortiz

Publications and source records attributed to M Ortiz.

At least 91 records · Page 5Linked to original sources
PubMed1997

[Subconjunctival anesthesia: an alternative for vitrectomy in mitochondrial myopathy].

The case of a 63-year-old woman with mitochondrial myopathy with palpebral ptosis and nighttime nasal home oxygen therapy is reported. The patient successfully underwent outpatient vitrectomy with subconjunctival anesthesia, receiving no premedication or sedation during the operation. Subconjunctival analgesia was provided, with prior instillation of an anesthetic collyrium followed by subconjunctival injection of 1 ml of 0.4% bupivacaine and 2% lidocaine. Analgesia during surgery was satisfactory. We review the possibilities of using this technique in patients at high risk of presenting postoperative complications after general anesthesia, and discuss the possible side effects on musculature when peribulbar or retrobulbar anesthesia is provided.

Anesthesia, Local↗
PubMed1996

Determination of the Isotope Shift of the 000 Band of the First Singlet-Singlet Electronic Transition of Cl- and Br-Benzene in a Supersonic Beam

By using resonance-enhanced two-photon ionization in a supersonic beam, photoionization spectra of the 0(0)0 band of the first singlet-singlet electronic transition of 35Cl-, 37Cl-, 79Br-, and 81Br-C6H5 have been obtained at a rotational temperature of 1 K. The ions have been analyzed according to their masses in a time-of-flight mass spectrometer. From the spectra of 35Cl- and 37Cl-C6H5 obtained simultaneously, an isotope shift of 0.14 +/- 0.02 cm-1 has been determined. Similarly, from the spectra of 79Br- and 81Br-C6H5 the isotope shift resulted to be smaller than 0.02 cm-1. The spectra obtained have been interpreted by considering the geometrical structure and symmetry of each molecule, and values for the rotational constants and geometrical parameters in the upper and lower states have been obtained in agreement with the experimental results.

Journal Article↗
PubMed1996

Raphe-septal neurons changes in sensitivity to desipramine following an early septal lesion in the rat.

1. The electrophysiological responsivity to desipramine (DMI) applied by systemic or local route was tested in Wistar female rats submitted to a wide lesion in the lateral septal area on the 8th day after birth. 2. One year after a septal lesion, the dorsal raphe nucleus (DRN) stimulation produced an initial brief response in lateral septal and CA1/CA3 neurons. In the control and sham-lesion groups, most recordings showed only this initial brief response (non-late responding neurons); however, in the lesion group most of the recorded neurons showed an afterdischarge. 3. DMI (2.14 mg/kg, 21 days, i.p.) increased the firing rate in septal and CA1/CA3 non-late responding neurons. In the equivalent septal neurons from lesion group, DMI produced the inverse effect, i.e., a decreased firing rate. 4. In septal non-late responding neurons, DMI (2 mM; 10-15 nAmps, 0.5 sec) applied by microiontophoresis increased the firing rate only after long-term systemic DMI impregnation. The response to locally applied DMI did not occur in the lesion group even after long-term DMI treatment. 5. In conclusion, an early lateral septal lesion canceled the response of intermediate-dorsal septal neurons to DMI applied by systemic and local routes.

Animals↗
PubMed1996

Thoracic epidural anesthesia via the lumbar approach in infants and children.

BACKGROUND: In upper abdominal or chest surgery, the segmental approach to thoracic epidural space has the advantage of reducing the total dose of local anesthetic needed. This approach, however, is associated with greater risk of neurologic damage or dural puncture. The aim of this study was to assess the success and the degree of difficulty in advancing a 19-G catheter from the lumbar epidural space to the thoracic level in patients aged 0-96 months. METHODS: In 39 patients undergoing abdominal surgery, the cutaneous distance between the L4-L5 and T10-T11 interspaces was measured, and an appropriate length of 19-G catheter was inserted into the epidural space through an 18-G Tuohy needle with bevel directed cephalad. The intent was to advance the full length of catheter measured to reach the objective. The tips were observed radiologically, and all those positioned cephalad to the T12 level were considered well placed. The degree of difficulty in advancing the catheter was classified as easy, difficult, or impossible. Complications reported were vascular and/or spinal puncture and difficulty removing the catheter. RESULTS: The catheter tip reached T10-T12 in 7 patients, L2 in 1, L3 in 8, and L4-L5 in 23. Forty-eight percent of the catheters described as easily advanced remained at the L4-L5 level, and only 22% reached the desired level. Difficult insertions occurred in eight patients, in whom the objective was never reached. One case of intravascular insertion was reported. All catheters were removed without difficulty. CONCLUSIONS: The 19-G catheter is inappropriate for use in reaching the thoracic epidural space by the lumbar approach. Easy entrance of a catheter is not a reliable sign of having reached the desired level.

Anesthesia, Epidural↗
PubMed1996

[Electric treatment of atrial fibrillation].

In the present manuscript the information concerning electrical therapy of atrial fibrillation (AF) to prevent its development and to control its consequences (excluding ablation which will be covered in separate manuscripts of this series) is reviewed. Both presently conventional approaches and those undergoing investigation will be considered, under three general headings. Electrical stimulation to prevent the development of AF. Based on non controlled studies comparing VVI stimulation with other modalities that include stimulation of the atria, it was suggested that atrial stimulation could prevent AF recurrences in patients with sinus node dysfunction. This concept has been questioned in recent studies. In contrast, the hypothesis that specific ways of atrial stimulation (stimulation at sites other than the high right atrium, multisite simultaneous or with certain "delays" atrial stimulation) may be more efficacious is presently under enthusiastic assessment. Electrical stimulation to control ventricular response. Despite the evidence that ventricular stimulation may contribute to regularization and rate control during AF, its quantitative value seems to be scarce and, thus, is not of regular use in practice. Automatic implantable atrial defibrillator. Both animal experiments and clinical studies have demonstrated that the atria can be defibrillated using intracavitary electrodes with less than 3 joules in most cases, and without risk of inducing ventricular tachyarrhythmias as long as shocks are synchronized to the R wave and the preceding R-R interval is not short. Although an implantable atrial defibrillator is already undergoing clinical evaluation, the subject of tolerability of patients to shocks for non malignant arrhythmias is still controversial, since even low energy shocks seem to be painful.

Atrial Fibrillation↗
PubMed1996

[Plasma concentrations and amiodarone/desethylamiodarone relations in patients subjected to chronic treatment].

We measured plasma concentrations of amiodarone and desethylamiodarone by HPLC in 44 outpatients aged 24 to 67 years old (21 male), receiving the drug during at least three months. The drug was indicated for supraventricular arrhythmias in 37 patients and ventricular arrhythmias in seven. Plasma concentrations of amiodarone, desethylamiodarone and their ratio were 1.71 +/- 0.82, 0.85 +/- 0.42 micrograms/ml and 2.02 respectively, for a mean daily dose of 223 +/- 88 mg. In 41 patients, arrhytmias were successfully treated. These patients received a mean daily dose of 220 +/- 86 mg and concentrations of amiodarone, desethylamiodarone and their ratio were 1.75 +/- 0.86, 0.88 +/- 0.45 micrograms/ml and 1.99 respectively. In three patients with treatment failure, receiving a daily dose of 257 +/- 115 mg, these figures were 1.2 +/- 0.3, 0.5 +/- 0.1 micrograms/ml and 2.4 respectively. We conclude that our patients had lower plasma concentrations of desethylamiodarone and higher amiodarone/desethylamiodarone ratios than those reported in other countries.

Adult↗
PubMed1996

Association of primary antiphospholipid syndrome with primary adrenal insufficiency.

The association of primary adrenal insufficiency with antiphospholipid antibodies is usually reported in the context of adrenal thrombosis or hemorrhage. We describe a 35-year-old woman who developed a primary antiphospholipid syndrome (spontaneous abortion, thrombocytopenia, and cerebrovascular occlusion) in association with primary adrenal insufficiency without evidence of suprarenal hemorrhage or thrombosis.

Addison Disease↗
PubMed1996

Update on the diagnosis and management of osteomyelitis.

Osteomyelitis can be classified by duration, pathogenesis, location, extent, and host status. Bone infections are currently classified by the Waldvogel or the Cierny-Mader classification. Because the Waldvogel classification is an etiologic system and the Cierny-Mader classification is descriptive, both classifications can be simultaneously used. The Cierny-Mader classification is based on the anatomy of the bone infection and the physiology of the host. Cierny-Mader staging allows stratification of long bone osteomyelitis and the development of comprehensive treatment guidelines for each stage. Current trends in long bone osteomyelitis therapy emphasize early diagnosis and aggressive treatment. Radiographs and bone cultures are the mainstays of diagnosis. Imaging with radionuclide scans, computerized tomography, and magnetic resonance imaging are used when the diagnosis of osteomyelitis is equivocal or to help guage the extent bone and soft tissue infection. Surgical treatment involves débridement of necrotic bone and tissue, obtaining appropriate cultures, managing dead space, and, when necessary, obtaining bone stability. Medical therapy includes improving any host deficiencies, initial antibiotic selection, and antibiotic modification based on culture results. Antibiotic delivery has expanded to include effective oral agents and local therapy with antibiotics mixed in polymethylmethacrylate. Cierny-Mader staging was developed to describe long bone osteomyelitis. This staging system has to be modified to describe diabetic foot osteomyelitis and vertebral osteomyelitis. Osteomyelitis in patients with diabetes mellitus involves the bones of the feet or ankles. The vascular and neurologic status of the patient must be carefully accessed. Patients may be managed with local débridement surgery or ablative surgery plus 2 to 4 weeks of antibiotic therapy depending on whether all of the osteomyelitis is surgically removed. If the patient does not wish surgery or is not a surgical candidate, suppressive antibiotic therapy can be used. Vertebral osteomyelitis is usually hematogenous in origin. The diagnosis is made by bone cultures, histology, and radiographs. Magnetic resonance imaging and technetium scans are useful in making the diagnosis and in gauging the extent of the bone and soft tissue infection. Therapy requires parenteral antibiotic therapy and may include early surgery and stabilization. The choice of an antibiotic therapy is guided by the bone biopsy or débridement culture results.

Adolescent↗
PubMed1995

Steel factor (c-kit ligand) promotes the survival of hematopoietic stem/progenitor cells in the absence of cell division.

It is known that the majority of primitive hematopoietic progenitors are in a noncycling quiescent state. In addition, normal hematopoietic progenitors and progenitor cell lines show an absolute dependence on growth factors for their survival in vitro, yet the effect of growth factors on progenitor cell survival has not been separated from effects on both proliferation and differentiation. Using an in vitro assay system, we examined whether growth factors could promote the survival of stem cells in culture in the absence of cell division. These studies show that steel factor (SLF) and, to a lesser extent, interleukin-3 (IL-3) directly promoted the survival of elutriated bone marrow progenitor cells (countercurrent centrifugal elutriation [CCE]-27) that are enriched for primitive hematopoietic progenitors that respond to the combination of SLF plus IL-3. Furthermore, SLF promoted the survival of short-term reconstituting cells (STRC), and long-term reconstituting cells (LTRC) with trilineage reconstitution potential in vivo. In comparison, granulocyte colony-stimulating factor (G-CSF), IL-6, leukemia inhibitory factor, IL-11, IL-1, granulocyte macrophage CSF (GM-CSF), and macrophage CSF (M-CSF) had no effect on the survival of these cells. In the presence of mitotic inhibitors (nocodazole or aphidicolin), SLF promoted the survival of CCE-27 progenitor cells that respond to the combination of SLF plus IL-3 in vitro and STRCs and LTRCs that are detected in vivo. Taken together, these data show that SLF can directly promote the survival of hematopoietic progenitor cells in the absence of cell division.

Animals↗
PubMed1995

Serum kinetics, bioavailability and bone scanning of 99mTc-labelled sodium olpadronate in patients with different rates of bone turnover.

The activity of olpadronate labelled with technetium-99m(99mTc) was monitored in plasma and urine samples after single oral (925 MBq 99mTc/10 mg, coadministered with 50 mg cold drug) and intravenous (925 MBq 99mTc/5 mg) administrations to two groups of patients with different rates of bone turnover. The first group comprised high bone turnover (HBTO) patients suffering from Paget's bone disease; the second group comprised patients with normal to low bone turnover (NBTO) having the diagnosis of rheumatoid arthritis and secondary osteoporosis. Kinetic variables were correlated with anthropomorphometric variables, biological markers of bone metabolism and plasma proteins. Data were also obtained after repeatedly dosing the HBTO patients. Additionally, Paget's bone and healthy bone (PB/HB) uptake before and after low-dose oral treatment were assessed by means of scintigraphy. Results showed that most of the kinetic variables did not differ between the two groups of patients, except for a greater Vss and smaller blood area under the curve AUC in the patients with HBTO. After a repeated-dose administration period, the blood AUC activity and Whole Body Retention (WBR) of the HBTO patients tended to be similar to those of the NBTO patients. In both groups, after oral dosing, the Cmax was 20 times lower than the C0.5 after i.v. injection, and the oral bioavailability ranged from 3% to 4%. Finally, the plasma t1/2 beta ranged from 9 to 14 h. Correlation coefficients were obtained from multiple regression analysis; kinetic variables showed very low correlations with anthropomorphometric measurements. In contrast the Vss and WBR were significantly correlated with serum alkaline phosphatase levels and the Vss also with urine hydroxyproline levels. Plasma protein concentration was also correlated with excretion parameters such as CLP and plasma t1/2 beta after an oral dose. Scintigraphic studies in the HBTO group allowed bone selectivity to be seen through skeletal drug uptake. The 15 Pagetic lesions analysed in the HBTO group showed a decrease in PB/HB ratio from 3.8 in the basal study to 2.7 after olpadronate administration for 30 days at the rate of 50 mg/day. In conclusion, the kinetic profile of 99mTc-labelled olpadronate, mainly AUC and WBR, showed a dependence upon bone metabolism and seemed unrelated to body size variables. HBTO patients showed a lower blood AUC but a higher Vss. Both variables may have been reflecting the fact that the drug binds selectively with calcified tissues and, in turn, with the target compartment. Scintigraphy confirmed the labelled-compound bone selectivity as a desirable feature for a bone-scanning agent.

Administration, Oral↗
PubMed1995

Selected nutritional and quality analyses of tomatillos (Physalis ixocarpa).

Proximate composition, total dietary fiber and pH of tomatillos (Physalis ixocarpa) grown in Baja, California were analyzed. Moisture content averaged 92%. On a dry matter basis (DMB), tomatillos contained 11% protein, 18% fat, 13% ash and 5% total dietary fiber. On an as consumed basis (ACB), tomatillos contained 1% protein, 1.5% fat, 1% ash and 0.4% dietary fiber. Carbohydrate (CHO) content was calculated by difference resulting in an average adjusted CHO (excluding dietary fiber) of 53% on a DMB and 4% on an ACB; total CHO (including dietary fiber) was 58 and 4.8%, respectively. Average kcalorie content was calculated to be about 31 kcals/100 g. The average pH of tomatillos was 3.76.

Dietary Carbohydrates↗
PubMed1995

Oral absorption of CGS-20625, an insoluble drug, in dogs and man.

Oral bioavailability of highly water-insoluble drugs is often quite limited and variable, requiring the development of improved formulations. Animal models are an essential aspect of the design and testing of such formulations designed to improve absorption in man. The present report compares the absorption of CGS-20625, an insoluble drug, in dog and man after oral administration of the drug as a powder, a solid dispersion capsule, and after gastric and duodenal administration in PEG 400 solution. CGS-20625 powder (20 mg) given orally exhibited slow, delayed absorption in both dog and man, with a Cmax of 0.26 +/- 0.07 microgram/ml at Tmax of 3 hr in dog, and 0.01 +/- 0.004 microgram/ml at 2 hr in man. Administration of CGS-20625 in PEG 400 solution improved absorption in dog and man, with a Cmax of 1.2 +/- 0.10 microgram/ml at Tmax of 0.25 hr in dog, and a Cmax of 0.10 +/- 0.04 microgram/ml at 0.5 hr in man. Tmax after administration of the hard gelatin capsule formulation was 0.9 and 1.0 hr in dog and man, with Cmax of 0.89 +/- 0.16 and 0.052 +/- 0.014 microgram/ml, respectively. Absolute bioavailability of CGS-20625 powder in the dog was 0.67 +/- 0.21, whereas the bioavailabilities of the powder and the capsule relative to the PEG 400 solution were 0.84 and 1.1, respectively, in dog, and 0.41 and 0.85 respectively, in man. No significant benefits of duodenal administration were observed. Plasma levels were approximately 10-fold greater and oral clearance was approximately 5-fold less in the dog than in man. Furthermore, pharmacokinetic data were less variable and relative bioavailability was greater in dogs than in humans. Physiological factors in the gastrointestinal tract or greater first-pass metabolism in man may account for these species differences. The relative rate and extent of CGS-20625 absorption were similar between dog and man, in the order of powder < capsule < PEG 400 solution. In addition, in vivo absorption rates in both species reflect in vitro dissolution differences between the powder and the capsule. These data strongly support the use of the dog as a model for developing improved formulations of CGS-20625. Further investigation of the dog as a model to evaluate insoluble drug absorption is warranted.

Absorption↗
PubMed1995

Importance of the lateral view in the evaluation of suspected brain death.

The authors present two cases of clinical brain death that failed to meet the criteria for whole brain death using Tc-99m HMPAO. Conventional anterior cerebral flow studies demonstrated no intracerebral perfusion. Anterior static images also failed to show cerebral activity. However, the lateral images clearly demonstrate cerebellar activity. These cases demonstrate the importance of Tc-99m HMPAO as the agent of choice in evaluating brain death and the necessity of lateral views to meet the criteria for whole brain death. Cerebellar perfusion challenges the present criteria for whole brain death. New criteria must re-evaluate the present technology.

Adolescent↗
PubMed1995

Prevalence of intestinal parasite infections among individuals with mental retardation in New York State.

The prevalence of intestinal parasite infection among program participants of the New York State Office of Mental Retardation and Developmental Disabilities for the period 1986-1987 was estimated, and demographic factors associated with increased risk for infection were identified. The overall prevalence of infection was 7.3%. The two most prevalent infections were Enterobius vermicularis (4.5%) and strongyloides stercoralis (1.2%). Males and individuals with severe or profound mental retardation were twice as likely to be positive for the presence of intestinal parasites as females and individuals with mild/moderate retardation. The relatively low prevalence found in this study compared with previous surveys suggests that management of parasitic infection is improving in conjunction with developments in delivery of medical and habilitative services.

Adolescent↗