Biomedical subjects

J M Martinez

Publications and source records attributed to J M Martinez.

At least 37 records · Page 2Linked to original sources

PubMed1998

Hemodynamic response to respiratory challenges in panic disorder.

This study compares the hemodynamic response to panic disorder subjects with that of normal controls during respiratory challenges. Panic patients meeting DSM-IIIR criteria for panic disorder and normal controls were challenged with room air hyperventilation, 5% CO2 breathing, and 7% CO2 breathing. Measurements of pulse and blood pressure were taken at resting baseline and before and at the end of each respiratory challenge. Panic attack to each challenge was determined by using raters blinded to subject diagnosis and each subject's self-rating of panic. Significantly larger systolic and diastolic blood pressure increases were found in patients who panicked with room air hyperventilation than nonpanicking patients or normal controls. No significant blood pressure differences were found with 7% or 5% CO2 challenges, but higher pulse rates were found in the patient group. It may be possible that panic with room air hyperventilation causes a significant increase in systolic and diastolic blood pressure, or that a subgroup of panic disorder patients has a hyperactive vascular response to hypocapnia. These patients panic with room air hyperventilation and develop greater vasoconstriction and/or increased blood pressure response.

Administration, Inhalation↗

PubMed1998

Natural evolution of nuchal thickness in trisomy-21 fetuses.

OBJECTIVE: To assess the natural evolution of nuchal thickness in trisomy-21 fetuses. METHODS: Serial measurements of nuchal thickness were performed over a 1- to 6-week period in 45 consecutive fetuses with trisomy 21, between the 10th and the 23rd weeks of pregnancy. To avoid a gestational age confounding effect, nuchal thickness also was expressed in standard deviations (SDs) for the corresponding gestational week. In addition, the changes were assessed in terms of the presence of clinical positive thickening, considered as such when the measurement was above 2.5 SD. RESULTS: A mean increase of 1.8 mm (95% confidence interval [CI] 1.3, 2.3) for nuchal thickness was observed for a mean period of 21 days. When corrected by gestational age, the mean increase of 0.3 SD (95% CI -0.2, 0.9) was found to be not significant. No clinically relevant nuchal thickening changes were recorded (51% versus 69%) at re-examination. CONCLUSION: Nuchal thickening at re-examination is observed in a similar proportion of trisomy-21 fetuses as when first observed.

Down Syndrome↗

PubMed1998

Fetal heart rate and nuchal translucency in detecting chromosomal abnormalities other than Down syndrome.

OBJECTIVE: To evaluate whether the combined use of fetal heart rate (FHR) and nuchal translucency measurements would be useful in the prediction of fetal chromosomal abnormalities at 10-13 weeks' gestation. METHODS: In a prospective study, 1053 (553 reported previously) consecutive singleton pregnancies between 10 and 13 weeks' gestation underwent chorionic villus sampling at our institution. Fetal heart rate and fetal nuchal translucency thickness were measured immediately before the invasive procedure. RESULTS: Thirty-five abnormal karyotypes were diagnosed, including 17 trisomy 21, seven trisomy 18, one trisomy 13, one trisomy 9, four unbalanced translocation, two Klinefelter syndrome, one Turner syndrome, one deletion of chromosome 18, and one true mosaicism. Using 95% of normal ranges as the cutoff for both measurements, the detection rate for all chromosomal anomalies was 77.1%, with a false-positive rate (1-specificity) of 7.7%, a positive predictive value of 25.7%, and a negative predictive value of 99.2%. Fetal heart rate improved the sensitivity of nuchal thickness in trisomies 21 and 18 (from 62.5% to 75%) and was particularly useful to detect other chromosomal anomalies (from 27.2% to 81.8%). CONCLUSION: Our findings suggest that there is an added role of FHR in ultrasound screening of chromosomal abnormalities, specifically for those other than trisomy 21 and 18. The value of a single measurement of fetal heart rate for screening purposes needs to be confirmed by further investigation in a low-risk population.

Adult↗

PubMed1998

Sex differences and in vitro effects of steroids on serum aminopeptidase activities.

We studied the possible existence of physiological sex differences in serum aminopeptidase activities in mice, by evaluating the effect of gonadectomy and the in vitro response to the presence in the medium of cholesterol or steroid hormones. Alanyl- and glutamyl-aminopeptidase activities were measured in sera from male, female, orchiectomized and ovariectomized mice, incubated with substrate solutions, and compared with the same groups of serum incubated with substrate solutions including cholesterol, 17-beta-estradiol, testosterone, progesterone or hydrocortisone. Our results demonstrated highly significant sex differences, and an influence of cholesterol and steroid hormones on aminopeptidase activity. Depending on the nature of the aminopeptidase, these enzymes responded in different ways to the presence of these substances and also responded differently to gonadectomy. For alanyl-aminopeptidase activity, but not for glutamyl-aminopeptidase activity, there was a clear difference in response between males and females to incubation of the serum with steroid hormones.

Aminopeptidases↗

PubMed1998

Activities of aminopeptidases in a rat saline model of volume hypertension.

Aminopeptidase activity plays a role in the metabolism of several peptides that could be involved in blood pressure control. This activity has been implicated in the pathogenesis of hypertension, essentially in spontaneously hypertensive rats. However, few studies have examined aminopeptidase activities in animal models other than genetic hypertension. To analyze the aminopeptidase response to the specific conditions of the reduced renal mass saline model of arterial hypertension, aminopeptidase A activity (glutamyl- and aspartyl-aminopeptidase), aminopeptidase M activity (alanyl-aminopeptidase), aminopeptidase B activity (arginyl-aminopeptidase), pyroglutamyl-aminopeptidase and cystinyl-aminopeptidase were measured in the neurohypophysis, in the adrenal gland and in serum of this model of hypertension. In the neurohypophysis, there was a significant increase of soluble cystinyl-, alanyl-, arginyl-, pyroglutamyl- and membrane-bound aspartyl-aminopeptidase activities in hypertensive animals. In the adrenal gland, soluble cystinyl-, alanyl-, arginyl- and pyroglutamyl-aminopeptidase activities were also higher in hypertensive rats than in normotensive controls. No differences were found in serum levels of aminopeptidase activities between both groups of animals. A highly significant positive correlation between the neurohypophysis and the adrenal gland was observed for soluble cystinyl- and alanyl-aminopeptidase activities in the model of hypertension, whereas no correlation was observed in normotensive rats. Our results suggest that aminopeptidase activities could be involved in the regulatory response to the reduced renal mass hypertension and also suggest a coordinate response between the adrenal gland and the neurohypophysis, to the specific metabolic conditions of this model of hypertension.

Adrenal Glands↗

PubMed1998

Cross-adaptation and molecular modeling study of receptor mechanisms common to four taste stimuli in humans.

Psychophysical cross-adaptation experiments were performed with two carbohydrates, sucrose (SUC) and fructose (FRU), and two sweeteners, acesulfame-K (MOD) and dulcin (DUL). Seven subjects were asked to match concentrations that elicited the same intensity as a sucrose reference (30 g/l). Cross-adaptation levels were calculated as the ratio of isointense concentrations measured for a given stimulus before and under adaptation. On average, cross-adaptation between SUC and FRU is low and apparently reciprocal. By contrast, cross-adaptation between SUC and MOD is clearly non-reciprocal: SUC adapts MOD significantly (24%, P < 0.005), but MOD fails to adapt SUC (2%, P < 0.79). Significant and reciprocal cross-enhancement is observed between DUL and MOD (approximately -20%, P < 0.03), and also between SUC and DUL (approximately -15%, P < 0.08). In parallel, molecular modeling of the four tastants was performed in order to look for the 12 common binding motifs that were isolated on 14 other tastants in a previous study. SUC and FRU each display 10 out of the 12 binding motifs, whereas DUL and MOD only display four and five distinct motifs respectively and do not have any motif in common. Experimental cross-adaptation levels seem to correlate well with the number of motifs that molecules have in common. FRU and SUC share a majority of binding motifs and correlatively show mutual cross-adaptation. Four motifs of MOD are found among the 10 motifs of SUC, which may explain why SUC cross-adapts MOD but not vice versa. By contrast, DUL and MOD do not share any motif and do not cross-adapt. The various molecular mechanisms that may be responsible for cross-adaptation and/or cross-enhancement are discussed in light of our results.

Female↗

PubMed1998

Analytical evaluation of an improved procedure for measuring thyrotropin.

The analytical characteristics of the AxSYM Ultrasensitive hTSH-II (Abbott Laboratories) procedure for quantitation of serum thyrotropin (TSH) concentration were evaluated. Within- and between-run imprecisions, functional sensitivity, analytical interval and relative inaccuracy with respect to the Enzymum-Test TSH (Boehringer Mannheim) were studied. In all cases, the within-run and between-run of coefficients variation were lower than 6.69% and 8.12% respectively. The measurement range was tested with serial dilutions of a serum with a high thyrotropin concentration, and the procedure was found to be linear up to at least 87.0 mIU/l. The functional sensitivity was 0.018 mIU/l. The relative inaccuracy study (Passing-Bablok non-parametric linear regression) produced the following linear equation: (AxSYM) = 1.02. (ES-700)-0.03 mIU/l, with 95% confidence intervals of a (-0.05; -0.01); b (0.98; 1.06).

Humans↗

PubMed1998

Breath of panic.

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Carbon Dioxide↗

PubMed1998

Tolerability of oral loading of divalproex sodium in the treatment of acute mania.

OBJECTIVE: To conduct a pilot study on the safety and tolerability of a dosage strategy for divalproex sodium beginning with 30 mg/kg/day. It is hypothesized that loading at this level will reach therapeutic levels of valproate more quickly, which in turn will decrease the latency of the therapeutic effect. METHOD: We conducted a retrospective chart review of all acutely manic patients admitted to our facility over a 12-month period. Those inpatients treated with initial divalproex sodium dosages of 30 mg/kg/day for 2 days, followed by 20 mg/kg/day thereafter, were then included in the study. The serum valproate levels and daily Brief Psychiatric Rating Scale (BPRS) scores were documented for each subject. Any adverse changes in daily vital signs, serum liver enzymes, and blood cell counts were noted as well. Nursing and physician notes were then reviewed for any observed or reported adverse effects. RESULTS: Twelve acutely manic inpatients were enrolled in the study. Three subjects did not complete the treatment and are not included in this analysis. The remaining nine subjects completed the treatment, had a mean decrease in BPRS scores of 33.3%, and were discharged at least in partial remission. Six subjects had serum valproate levels drawn within 48-72 h of the initial dose, with a mean valproate level of 93.5 mcg/ml. All nine subjects tolerated the treatment reasonably well, with one subject reporting sedation, one reporting sedation and constipation, and one reporting nausea, emesis, and urinary frequency. A transient, asymptomatic decrease in white blood cell count and a low granulocyte count were also noted in one subject. CONCLUSION: A divalproex dosage strategy beginning with 30 mg/kg/day for 2 days, followed by 20 mg/kg/day thereafter, was reasonably well tolerated in this group of acutely manic patients, even with the concurrent use of other psychotropic medications. Blood levels of 56 to 124 mcg/ml were observed within 3 days after initiating treatment.

Acute Disease↗

PubMed1998

Low-dose venlafaxine treatment in panic disorder.

Venlafaxine, a structurally novel antidepressant that combines mechanisms of action of both the cyclic antidepressants and SSRIs, may be effective in the treatment of panic disorder. Thirteen patients with DSM-IV panic disorder with or without agoraphobia participated in an open-label, fixed-flexible dose treatment study with venlafaxine. All patients who completed the 10-week trial exhibited statistically significant decreases in scores on anxiety symptoms as well as complete cessation of panic attacks at an effective mean daily dose of 47 mg per day. Venlafaxine was well tolerated in all completers. Venlafaxine may be an effective antipanic agent, even at lower than typical antidepressant dosages.

Adult↗

PubMed1997

Renal aminopeptidase activities in animal models of hypertension.

Aminopeptidase activity (AP) has been implicated in the metabolism of renal and circulating vasoactive peptides. This activity is involved in the pathogenia of hypertension, essentially in spontaneously hypertensive rats. However, no other animal models, which develop hypertension by other different ways, have been used to study the possible role of aminopeptidase activity. To investigate the role of this activity in the pathogenesis of hypertension, angiotensinase A activity (glutamyl-AP and aspartyl-AP), aminopeptidase M activity (alanyl-AP), aminopeptidase B activity (arginyl-AP), pyroglutamyl-AP, and cystinyl-AP were measured in the serum and kidney of two experimental animal models of renovascular hypertension: Goldblatt two-kidney one clip (G2K-1C) and low renal mass rats (LRM). No differences were found in serum levels of AP in LRM or G2K-1C in comparison with their respective controls. In LRM rats there was a significant decrease in membrane-bound angiotensinase A (glutamyl-AP), arginyl-AP and alanyl-AP activities. In G2K-1C rats there was a significant decrease in soluble and membrane-bound angiotensinase A activity (aspartyl-AP). Our results suggest that AP activities play a role in the regulation of renal vasoactive peptides, and respond differently depending on the cause of hypertension.

Aminopeptidases↗

PubMed1997

Brachycephaly is ineffective for detection of Down syndrome in early midtrimester fetuses.

The aim of this study was to assess the value of fetal brachycephaly in the detection of Down syndrome at 13-18 weeks of pregnancy. The cephalic index (CI) was determined in 555 consecutive chromosomally normal fetuses, and in 38 chromosomal abnormalities, prior to amniocentesis. A CI > 0.85 was observed in 14% (2/14) of the fetuses with Down syndrome and in 11% of the normal fetuses. In conclusion, our data show that brachycephaly is not a useful marker for Down syndrome in early midtrimester fetuses.

Adolescent↗

PubMed1997

Umbilical Doppler velocimetry in fetuses with trisomy 18 at 10-18 weeks' gestation.

The aim of our study was to obtain measurements of the umbilical artery pulsatility index (PI) in pregnancies before invasive procedures for prenatal diagnosis, in order to investigate its potential prognostic value in predicting trisomy 18. We performed a prospective study including 1785 consecutive women from 10 to 18 weeks with singleton pregnancies undergoing chorionic villus sampling (n = 559) or genetic amniocentesis (n = 1226) in our unit. Doppler measurements were performed transvaginally (tenth to 13th week of gestation) or transabdominally (14th to 18th week of gestation) immediately before the invasive procedure. In 7 out of 10 fetuses subsequently diagnosed as trisomy 18, the PI was above the 95th centile, providing a detection rate of 70 per cent, a specificity of 95.1 per cent, a positive predictive value of 7.7 per cent, and a negative predictive value of 99.8 per cent. When the 90th percentile was assayed as a cut-off, the efficacy of PI as a marker of trisomy 18 yielded a sensitivity of 90 per cent and a specificity of 90.4 per cent, with a positive predictive value of 5.2 per cent and a negative predictive value of 99.9 per cent. We suggest that although the use of a single PI measurement for screening purposes needs to be confirmed by further investigation, trisomy 18 fetuses show an abnormal increase in umbilical PI in the first half of pregnancy, and its relation to the early onset of fetal growth retardation needs to be further explored.

Blood Flow Velocity↗

PubMed1997

Interobserver variability of midtrimester fetal nuchal thickness.

OBJECTIVE: To assess the interobserver variability of ultrasound measured fetal nuchal thickness (NT). STUDY DESIGN: NT was measured in 103 consecutive early midtrimester pregnancies (13-18 weeks) by three ultrasonographists with different levels of expertise, in our Prenatal Unit. Measurements were obtained prior to amniocentesis, blindly in relation to other examiners' values. The Lin's concordance correlation coefficient and the Kappa statistics were used to assess concordance between observed values. RESULTS: Mean differences between pairs of observers ranged from 0.44 to 0.57 mm. A higher concordance correlation between measurements was obtained between the more experienced observers (r = 0.77 versus r = 0.51). When assigning cases with a NT > or = 5 mm to a group at risk for Down's syndrome, a high concordance between experienced ultrasonographists was observed (98% agreement; kappa = 0.90). CONCLUSIONS: Interobserver variability in NT was acceptable between experienced ultrasonographists.

Adult↗

PubMed1997

Cholesterol and steroids action on aminopeptidases.

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Aminopeptidases↗

PubMed1997

Effects of the antipsychotic drug sulpiride on reproductive hormones in healthy premenopausal women: relationship with body weight regulation.

Metabolic and endocrine abnormalities secondary to hyperprolactinemia, such as hypogonadism and hyperandrogenicity, may be involved in the excessive body weight gain induced by antipsychotic drugs in women. The present study was conducted in healthy premenopausal women, in order to detect an endocrine imbalance secondary to antipsychotic drug administration, which, if sustained in the long term, might be involved in the development of obesity. After a control menstrual cycle, sulpiride (200 mg/day) or placebo was nonblindly administered for 28 days; blood lipids and the serum levels of the following hormones which are involved in body weight regulation were assessed at days 3, 10, 20 and 26 of the cycle: prolactin (PRL), 17-beta estradiol (E2), progesterone (P4), follicle stimulating hormone (FSH), luteinizing hormone (LH), free testosterone (T5), dehydroepiandrosterone sulfate (DHEAS), cortisol, tyrotropic hormone (TSH), tetraiodothyroxine (T4), and the areas under the insulin and glucose tolerance curve. During sulpiride administration, the following changes were observed when compared to placebo administration: PRL levels were significantly increased; E2 levels were significantly reduced at days 10 and 20; P4 levels were significantly reduced at day 20, and the area under the glucose tolerance curve was significantly increased. The other variables were not significantly affected. The body weight gain was higher during sulpiride than during placebo administration, but it did not reach statistical significance, perhaps because the period of treatment was too short. The decrease in the serum levels of E2 during sulpiride administration is probably secondary to hyperprolactinemia. It affects the E2/T5 ratio in the direction of increasing the androgenic activity, as observed in women with well-established obesity. This effect, along with a genetic predisposition, increased appetite, hypoactivity and ignorance of proper dietary habits, may explain the excessive weight gain and obesity observed in women during chronic treatment with sulpiride and other antipsychotic agents.

Adult↗

PubMed1997

Laparoscopic versus open Nissen fundoplication: outcome of surgery in monozygotic twins.

Differences in outcome and cost of laparoscopic and open surgery are continuously being evaluated. Two-year-old monozygotic twin boys with a previous history of prematurity, severe gastroesophageal reflux disease, and intractable reactive airway disease were each scheduled to undergo a laparoscopic Nissen fundoplication (LNF) on the same day. Current medications for both patients included albuterol, cromolyn sodium, dexamethasone, ranitidine, and metoclopramide. In the first case, the laparoscopic procedure was converted to an open Nissen fundoplication (ONF) to gain expeditious control of bleeding from a short gastric vessel close to the spleen. The second patient underwent LNF without complication. Operative time for each patient was 3.5 h. The postoperative length of stay for each patient was 6 days (ONF) and 4 days (LNF). The total hospital charges were $21,931 (ONF) and $19,108 (LNF). The first patient (ONF) was readmitted later on the day of discharge (postoperative day 6) for vomiting and was discharged after 24 h with no further treatment. The subsequent course of each patient was similar. At a 6-week follow-up visit, both patients were tolerating a regular diet with weight gain and dramatic improvement in pulmonary symptoms.

Child, Preschool↗

PubMed1997

Combining nuchal translucency with umbilical Doppler velocimetry for detecting fetal trisomies in the first trimester of pregnancy.

OBJECTIVE: The aim of our study was to evaluate whether the combined use of umbilical artery pulsatility index (UAPI) and nuchal translucency (NT) measurements would be useful in the prediction of fetal chromosomal abnormalities at 10 to 13 weeks of gestation. DESIGN: A prospective study. POPULATION AND METHODS: Five hundred and fifty-three consecutive women with singleton pregnancies between 10 and 13 weeks of gestation, who underwent chorionic villus sampling at our institution. UAPI and fetal NT thickness were measured immediately before the invasive procedure. Pregnancies in which structural malformations had been detected by ultrasound were excluded. RESULTS: Using the 95th centile and 3 mm as the cutoffs for UAPI and NT, respectively, the detection rate for all chromosomal anomalies was 84.2%, with a false positive rate (1-specificity) of 6.6%, a positive predictive value of 31.3%, and a negative predictive value of 99.4%. Out of the 553 tested pregnancies 502 had both parameters within the normal range and only three of them (0.6%) were chromosomally abnormal; in six of the eight cases (75%) in which both parameters were abnormal a chromosome anomaly was present. Of the 43 cases in which only one parameter was abnormal, 10 were chromosomally abnormal (23.2%). CONCLUSIONS: Our results suggest that the presence of chromosomal anomalies may be strongly suspected when an increased NT thickness (NT > or = 3 mm) is associated with an abnormally high UAPI at 10 to 13 weeks of gestation. The number of cases studied is small, however, and these conclusions are tentative and preliminary. The value of a single measurement of NT and UAPI for screening purposes needs to be substantiated by further investigation.

Adult↗