Absence of diabetes mellitus type 2 in obese children and adolescents in the north of Spain

BACKGROUND

The worldwide epidemic of childhood obesity has been accompanied by an increase in the incidence of carbohydrate metabolism disorders.

OBJECTIVE

To determine the prevalence of type 2 diabetes mellitus (T2DM) and other carbohydrate metabolism disorders in obese young people in the Basque Country (Spain).

DESIGN

Prospective observational study.

PATIENTS

We studied 136 obese Caucasian children and adolescents (body mass index ≥2 SDS above the mean).

MEASUREMENTS

Their severity of obesity was classified as mild <3 SDS or moderate-to-severe ≥3 SDS. Data were collected on clinical and metabolic parameters; insulin resistance (IR) was calculated using the homeostasis model assessment, and an oral glucose tolerance test (OGTT) was carried out.

RESULTS

T2DM was not found. Impaired glucose tolerance (IGT) was found in 9.6% of patients being higher in moderate-to-severe obesity (12.8% vs. 2.4%; p=0.048) and in patients with acanthosis nigricans (27.8% vs. 6.8%; p=0.016). No differences were detected by sex or pubertal development in metabolic results as a function of OGTT's response. IR (13.5%) was higher among those with moderate-to-severe obesity, in patients with acanthosis nigricans and was associated with other cardiovascular disease risk factors.

CONCLUSIONS

We found no children with T2DM. The prevalence of IGT and IR was related to severity of obesity, to the association of acanthosis nigricans and was associated with cardiovascular risk.

Analysis of relapses in anti-NMDAR encephalitis

OBJECTIVE

The clinical characteristics of patients with relapsing anti-NMDA receptor (NMDAR) encephalitis are not well-defined. In this study, we report the clinical profile and outcome of relapses in a series of anti-NMDAR encephalitis.

METHODS

We did a retrospective review of relapses that occurred in 25 patients with anti-NMDAR encephalitis. Relapses were defined as any new psychiatric or neurologic syndrome, not explained by other causes, which improved after immunotherapy or, less frequently, spontaneously.

RESULTS

A total of 13 relapses were identified in 6 patients. Four of them had several, 2 to 4, relapses. There was a median delay of 2 years (range 0.5 to 13 years) for the first relapse. Median relapse rate was 0.52 relapses/patient-year. Relapse risk was higher in patients who did not receive immunotherapy in the first episode (p = 0.009). Most cases (53%) presented partial syndromes of the typical anti-NMDAR encephalitis. Main symptoms of relapses were speech dysfunction (61%), psychiatric (54%), consciousness-attention disturbance (38%), and seizures (31%). Three relapses (23%) presented with isolated atypical symptoms suggestive of brainstem-cerebellar involvement. An ovarian teratoma was detected at relapse in only 1 patient (17%). Relapses did not add residual deficit to that caused by the first episode.

CONCLUSIONS

Relapses in anti-NMDAR encephalitis are common (24%). They may occur many years after the initial episode. Relapses may present with partial aspects or with isolated symptoms of the full-blown syndrome. Immunotherapy at first episode reduces the risk of relapses.

[SOD1-N196 mutation in a family with amyotrophic lateral sclerosis]

INTRODUCTION

N19S mutation is produced by substitution in the 139 position of SOD1 and was described by Mayeux in a patient with amyotrophic lateral sclerosis (ALS). He suggested that it did not have a causal effect as it was found in asymptomatic and sporadic cases. Other authors in later articles did not agree.

MATERIAL AND METHODS

We describe a family with 4 members with ALS patients and attempt to find the carrier of the N19S mutation of the propositus. Molecular studies were performed on 15 members of the family of a different order.

RESULTS

The ALS cases were found in the maternal line of the propositus. The presence of the mutation was detected in 3 people, the other two were asymptomatic. One of patients with ALS in the family, who died previously, did not have the mutation. Two of the sons of this case and another of the other case did not show it. On the other hand, N19S mutation was only present in paternal branch of the propositus, where there were no cases.

CONCLUSION

The described family supports the hypothesis by Mayeux and against that mutation N19S has pathological consequences, since mutation is only in the family line where there are no cases with ALS. In consequence, although the described case is included as a familiar form, it cannot be attributed to the mutation, and its relationship with N19S should be considered as casual.

Familial hyperinsulinism-hyperammonemia syndrome in a family with seizures: case report

Hyperinsulinism-hyperammonemia (HI/HA) syndrome is the second most frequent cause of congenital hyperinsulinism (CHI) and it is characterized by recurrent symptomatic hypoglycemia and persistent hyperammonemia. We describe the familial case of a 2-year-old child and her 32-year-old mother who, having suffered from tonic-clonic seizures since infancy, had both been diagnosed with epilepsy and treated with sodium valproate. Hypoglycemia was identified in the child in routine analysis. Six days after admission, a complete study of hypoglycemia showed test results compatible with hyperinsulinemic hypoglycemia and hyperammonemia. A mutation in the GDH gene (Arg269His) confirmed the diagnosis in both the mother and the child. An important peculiarity of this case is the diagnosis of a 32-year-old woman, previously diagnosed with epilepsy through her daughter's diagnosis at a Pediatric Endocrinology Department and subsequently treated ineffectively with sodium valproate. We conclude that, as hypoglycemia may be subtle, the diagnosis of HI/HA should be considered in children or adults with seizures/epilepsy and hyperammonemia, serum ammonia being a simple screening test for the disease.

[Analysis of hospital consultations to Neurology in a tertiary hospital.]

Introduction. Neurology consultations requested by other services in in-patients are performed through intrahospital consultations. This study aims to make a descriptive study of the intrahospital consultations (IHC) requests received by a Neurology service. Material and methods. We conducted a retrospective study of the requests for consultations received in the Neurology Service in the Hospital Universitario Clínico San Carlos in Madrid during the year 2007. The following endpoints were analyzed: number of consultations, number of visits made, date, delay in attention, specialties involved, syndromic diagnosis, final diagnosis and complementary tests requested. Results. A total of 390 intrahospital consultations corresponding to 351 patients were made. Total number of visits was 687. Internal Medicine was the specialty making the most requests with 31%, followed by Psychiatry (13.4 %) and Oncology (8 %). The most frequent syndromic diagnoses were neurological deficit (31.6%), seizures (18.2%) and awareness level disturbance (11.7%). The most frequent final diagnoses were epilepsy (19.9 %), cerebrovascular disease (15%) and movement disorders (10.5 %). Complementary tests were requested for 37% of the patients, the most common ones being cranial and spinal magnetic resonance imaging, Head CT and EEG. Conclusions. Because of its complexity and care load, intrahospital consultation should be considered an independent unit in the organization of a neurological service. As it involves a significant number of patients, it should be subject to evaluation and quality improvement programs.

The DOSIMAP, a high spatial resolution tissue equivalent 2D dosimeter for LINAC QA and IMRT verification

The continual need for more accurate and effective techniques in radiation therapy makes it necessary to devise new control means combining high spatial resolution as well as high dose accuracy. Intensity modulated radio therapy (IMRT) allows highly conformed fields with high spatial gradient and therefore requires a precise monitoring of all the multileaf positions. In response to this need, the authors have developed a new 2D tissue equivalent dosimeter with high spatial resolution. A plastic scintillator sheet is sandwiched between two polystyrene blocks and the emitted light is captured by a high resolution camera. A newly developed procedure described herein allows efficient discrimination of the scintillation from the parasitic Cerenkov radiation. This processing is applied on the cumulated image from a sequence of images taken during an irradiation field at a rate of 10 images/s. It provides a high resolution mapping of the cumulated dose in quasireal time. The dosimeter is tissue equivalent (ICRU-44) and works both for electrons and photons without complex parameter adjustment since phantom and detector materials are identical. Instrument calibration is simple and independent of the irradiation conditions (energy, fluence, quality, ...). In this article, the authors present the principle of the dosimeter and its calibration procedure. They compare the results obtained for photons and electron beams with ionization chamber measurements in polystyrene. Technical specifications such as accuracy and repeatability are precisely evaluated and discussed. Finally, they present different IMRT field measurements and compare DOSIMAP measurements to TPS simulations and dosimetric film profiles. The results confirm the excellent spatial resolution of the instrument and its capacity to inspect the leaf positions for each segment of a given field.

DOSIMAP: a high-resolution 2-D tissue equivalent dosemeter for linac QA and IMRT verification

New generation of radiation therapy accelerators requires highly accurate dose measurements with high spatial resolution patterns. IMRT is especially demanding since the positioning accuracy of all the multi-leafs should be verified for each applied field and at any incidence. A new 2-D tissue equivalent dosemeter is presented with high spatial resolution that can fulfil these tasks. A plastic scintillator sheet is sandwiched between two polystyrene cubes, and the emitted light is observed by a high-resolution camera. A patented procedure allows efficient discrimination of the scintillation proportional to the dose from the parasitic Cerenkov radiation. This extraction made on the cumulated images taken during an irradiation field at a rate of 10 images s(-1) provides high-resolution mapping of the dose rate and cumulated dose in quasi real time. The dosemeter is tissue equivalent (ICRU-44) and works both for electrons and photons without complex parameter adjustment, since phantom and detector materials are identical. The calibration is simple and independent of the irradiation conditions (energy, fluence, quality and so on). The principle of the dosemeter and its calibration procedure are discussed in this paper. The results and, in particular, the dose depth profiles are compared with standard ionisation chamber measurements in polystyrene for both photons and electrons. Finally, the detector specifications are summarised and one example of complex IMRT field is discussed.

The DosiMap, a new 2D scintillating dosimeter for IMRT quality assurance: characterization of two Cerenkov discrimination methods

New radiation therapy techniques such as IMRT present significant efficiency due to their highly conformal dose distributions. A consequence of the complexity of their dose distributions (high gradients, small irradiation fields, low dose distribution, ...) is the requirement for better precision quality assurance than in classical radiotherapy in order to compare the conformation of the delivered dose with the planned dose distribution and to guarantee the quality of the treatment. Currently this control is mostly performed by matrices of ionization chambers, diode detectors, dosimetric films, portal imaging, or dosimetric gels. Another approach is scintillation dosimetry, which has been developed in the last 15 years mainly through scintillating fiber devices. Despite having many advantages over other methods it is still at an experimental level for routine dosimetry because the Cerenkov radiation produced under irradiation represents an important stem effect. A new 2D water equivalent scintillating dosimeter, the DosiMap, and two different Cerenkov discrimination methods were developed with the collaboration of the Laboratoire de Physique Corpusculaire of Caen, the Comprehensive Cancer Center François Baclesse, and the ELDIM Co., in the frame of the MAESTRO European project. The DosiMap consists of a plastic scintillating sheet placed inside a transparent polystyrene phantom. The light distribution produced under irradiation is recorded by a CCD camera. Our first Cerenkov discrimination technique is subtractive. It uses a chessboard pattern placed in front of the scintillator, which provides a background signal containing only Cerenkov light. Our second discrimination technique is colorimetric. It performs a spectral analysis of the light signal, which allows the unfolding of the Cerenkov radiation and the scintillation. Tests were carried out with our DosiMap prototype and the performances of the two discrimination methods were assessed. The comparison of the dose measurements performed with the DosiMap and with dosimetric films for three different irradiation configurations showed discrepancies smaller than 3.5% for a 2 mm spatial resolution. Two innovative discrimination solutions were demonstrated to separate the scintillation from the Cerenkov radiation. It was also shown that the DosiMap, which is water equivalent, fast, and user friendly, is a very promising tool for radiotherapy quality assurance.

[Cellular therapy in amyotrophic lateral sclerosis]

INTRODUCTION

The possible role of stem cells transplantation in therapy for traumatic lesions or for diseases has been outlined in recent years. Amyotrophic lateral sclerosis (ALS) is one of the diseases where cellular therapy may be useful.

DEVELOPMENT

The authors make an analytic review of the studies carried out in humans with ALS and in G93A transgenic rodent model of ALS to evaluate the effect of stem cell transplantation. They also review cellular responses from NSC-EZ cells in the spinal cord.

CONCLUSIONS

Research on the potential uses of cellular therapy for ALS is on-going, however, the different studies are not homogeneous. Thus, many questions need to be answered, such as which is the most appropriate type of cells or which should be the volume of cells to implant, which is the best method for the transplantation and in the case of spinal cord implant which is the best target for the implant, or if it is necessary to administer concomitant substances, such as immunosuppressant drugs.

[Analytic epidemiological information of amyotrophic lateral sclerosis]

INTRODUCTION

The analytical epidemiological information on amyotrophic lateral sclerosis (ALS) is extensive and is based on case-control studies, selective patient series and few cohort studies that analyze the risk factors for the disease.

REVIEW

The studies found in the literature on analytical epidemiology have been reviewed in an attempt to analyze the methodology, compare their results and comment on the possible biases and confounding factors such as the different roles of the risk factors.

CONCLUSION

In spite of the extensive information available, the analytical epidemiology of ALS has still not clarified the etiological factors of the disease. This may be due to the influence of the genetic factors, but also to the variability of the methodological designs. However, the analytical factor that has the greatest consistency is that of exhibition to heavy metals. Greater physical activity or increased frequency in special situations such as is the cases from the first Gulf War could be suggested as a more than casual precipitating factor.

[Descriptive epidemiology of amyotrophic lateral sclerosis]

INTRODUCTION

ALS descriptive epidemiological information is wide, and is based on hospital registries, selective patients series and community studies of incidence, prevalence and mortality rates.

REVIEW

It has been revised studies found in the literature trying to analyse the methodology looking for approaches for a systematic review on the ALS descriptive epidemiology. The analysed works include on incidence, prevalence and mortality rates studies and we discuss possible biases and confounding factors.

CONCLUSIONS

Systematic review of ALS descriptive epidemiology should be based on the following criteria: community studies in non-selective geographic areas excluding aggregated cases zones, determination of crude prevalence rate and sex-age specific and standard population adjusted prevalence rates, presented with confidence intervals, selection of the cases should fulfil El Escorial criteria, sample size of source population greater than one hundred thousands in habitants, study period greater than five years and the dates should be accessible through Medline or other bibliographic sources.

[Experimental models of amyotrophic lateral sclerosis]

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a serious neurodegenerative disease that affects almost selectively motor neurons. Its ethiopathogeny is not fully understood, although there are several mechanisms that could play a role. It has no curative treatment and just a drug (riluzole) and mechanical ventilation has demonstrated to improve survival of these patients. In the last decades experimental models have been developed which have led us to better understand this disease and to design possible therapeutic strategies.

METHOD

We reviewed published articles concerning experimental models for ALS and neurodegeneratives diseases using the PubMed database.

RESULTS

Several experimental models for ALS have been described, from animal models (mainly transgenic animals for human mutations in superoxidedismutase [SOD1]) to cellular models, each of them with advantages and objections.

CONCLUSIONS

ALS experimental models have implied a great advance in the knowledge of this disease and the design of new therapeutic strategies.

Cardiovascular risk factors in the urban Mexican population: The FRIMEX study

BACKGROUND

Atherosclerotic ischaemic heart disease is the second leading cause of general mortality in Mexico due to the growing prevalence of atherosclerotic risk factors in our society. The data of the FRIMEX study (Factores de Riesgo en México, Risk Factors in Mexico), considered together with those of other contemporary epidemiological surveys, will aid in our comprehension of the current state of cardiovascular epidemics in Mexico.

METHODS

Frequencies of obesity, hypertension and smoking, and total cholesterol and glucose in capillary blood were estimated in a non-probabilistic sample comprised of 140017 individuals (aged 44+/-13 years; 42% men and 58% women), from six Mexican cities (Mexico City, Guadalajara, Monterrey, Puebla, Leon and Tijuana).

RESULTS

Obesity or overweight status was found in 71.9% of participants. Hypertension was found in 26.5%, and the proportions of awareness, treatment and control for this disease were 49.3, 73 and 36%, respectively. Prevalence of hypertension increased with age; while it was higher in men under 60 years of age, in the more aged individuals it was higher in women. Hypercholesterolaemia was found in 40% of the individuals and cholesterolaemia > or =240 mg/dl was significantly higher in women. Thirty-five and a half percent of men and 18.1% of women were smokers. Type 2 diabetes mellitus was found in 10.4% of participants. There was significant Pearson's correlation between body mass index and blood pressure, between hypertension and glucose levels, and between hypertension and total cholesterol concentrations.

CONCLUSIONS

We conclude that this population has a high cardiovascular risk profile and a high probability of the occurrence of metabolic syndrome.

Panhypopituitarism: genetic versus acquired etiological factors

OBJECTIVE

Mutations in the genes encoding pituitary transcription factors (mainly PROP1, POUF1 and HESX1) are responsible for familial combined pituitary hormone deficiency (CPHD) and septo-optic dysplasia (SOD) while only a low percentage of mutations are the cause of sporadic forms. Indeed, it has been suggested that environmental rather than genetic factors could be important in the pathogenesis of CPHD.

PATIENTS AND METHODS

Thirty-six sporadic patients diagnosed with CPHD or SOD were included in the study. All coding exons and intron-exon boundary regions of PROP1, POUF1 and HESX1 were amplified by PCR and subsequently sequenced.

RESULTS

Two novel missense mutations in the HESX1 gene (Q117P, K176T) were identified in two patients. Polymorphisms in PIT1 and PROP1 were also detected. A higher percentage of breech delivery in male patients with CPHD versus females was observed.

CONCLUSIONS

The low percentage of mutations found in the most common transcription factors involved in CPHD show that a better characterization of hormonal and morphological phenotypes is necessary for patients with CPHD included in genetic studies, and other genetic or non-genetic factors have to be taken into account.

Spectral discrimination of Čerenkov radiation in scintillating dosimeters

Radiation therapy accelerators require highly accurate dose deposition and the output must be monitored frequently and regularly. Ionization chambers are the primary tool for this control, but their size, their high voltage needed, and the correction needed for electrons make them unsuitable for use during patient treatment. We have developed a small (1-mm-diam and 1-mm-long active part), flexible, and water-equivalent dosimeter. It is suitable for photon and electron beams without corrections, and performs on line dose measurements. This detector is based on only one scintillating fiber and a CCD camera. A new signal processing is used to remove the effect of Cerenkov radiation background, which only requires a preliminary calibration. Central-axis depth-dose distribution comparisons have been achieved with standard ionization chambers, over a range from 8 to 25 MV photons and from 6 to 21 MeV electrons in order to validate this calibration. Results show a very good agreement, with less than 1% difference between the two detectors.

Comparative studies of the spectroscopy of CuCl2: DFT versus standard ab initio approaches

The X2Pi g-2Sigma g+, X2Pi g-2Delta g, X2Pi g-2Sigma u+, X2Pi g-2Pi u transitions on CuCl2 have been studied using several exchange-correlation functionals from the various types of density functional theory (DFT) approaches like local density approximation (LDA), generalized gradient approximation (GGA), hybrid and meta-GGA. The results are compared with the experience and with those coming from the most sophisticated nondynamic and dynamic electronic correlation treatments using the same relativistic effective core potentials and especially developed basis sets to study the electronic structure of the five lowest states and the corresponding vertical and adiabatic transition energies. The calculated transition energies for three of the hybrid functionals (B3LYP, B97-2, and PBE0) are in very good agreement with the benchmark ab initio results and experimental figures. All of the other functionals largely overestimate the X2Pi g-2Sigma g+ and X2Pi g-2Delta g transition energies, many of them even placing the 2Delta g ligand field state above the charge transfer 2Pi u and 2Sigma u+ states. The relative weight of the Hartree-Fock exchange in the definition of the functional used appears to play a key role in the accurate description of the LambdaSSigma density defined by the orientation of the 3d hole (sigma, pi, or delta) on Cu in the field of both chlorine atoms, but no simple connection of this weight with the quality of the spectra has been found. Mulliken charges and spin densities are carefully analyzed; a possible link between the extent of spin density on the metal for the X2Pi g state and the performance of the various functionals was observed, suggesting that those that lead to the largest values (close to 0.65) are the ones that best reproduce these four transitions. Most functionals lead to a remarkably low ionicity for the three ligand field states even for the best performing functionals, compared to the complete active space (SCF) (21, 14) ab initio values. These findings show that not only large variational ab initio calculations can produce reliable spectroscopic results for extremely complex systems where delicate electronic correlation effects have to be carefully dealt with. However, those functionals that were recently shown to perform best for a series of molecular properties [J. Chem. Phys. 121 3405 (2004)] are not the ones that produce the best transition energies for this complex case.

Circulating non-22 kDa growth hormone isoforms after a repeated GHRH stimulus in normal subjects

The aim of this study was to evaluate the proportion of non-22 kDa GH isoforms in relation to total GH concentration after a repeated GHRH stimulus in healthy subjects. We studied 25 normal volunteers (12 males and 13 females, mean age 13.1 years, range 6-35), who received two GHRH bolus (1.5 mug/kg body weight, i.v.) administered separately by an interval of 120 minutes. The proportion of non-22 kDa GH was determined by the 22 kDa GH exclusion assay (GHEA), which is based on immunomagnetic extraction of monomeric and dimeric 22 kDa GH from serum, and quantitation of non-22 kDa GH isoforms using a polyclonal GH assay. Samples were collected at baseline and at 15-30 min intervals up to 240 min for total GH concentration. Non-22 kDa GH isoforms were measured in samples where peak GH after GHRH was observed. Total GH peaked after the first GHRH bolus in all subjects (median 37.2 ng/ml; range: 10.4-94.6). According to GH response to the second GHRH stimulus, the study group was divided in "non-responders" (n=7; 28%), with GH peak levels lower than 10 ng/ml (median GH: 8.7 ng/ml; range 7.3-9.6) and "responders" (n=18; 72%), who showed a GH response greater than 10 ng/ml (median 17 ng/ml; range 10.1-47.0). The median proportion of non-22 kDa GH on the peak of GH secretion after the first GHRH administration was similar in both groups ("responders" median: 8.6%, range 7-10.9%; "non-responders" median: 8.7%, range 6.7-10.3%), independently of the type of response after the second GHRH. In contrast, the median proportion of non-22 kDa GH was greater at time of GH peak after the second GHRH bolus in the "non-responders" (median 11.4%; range 9.1-14.3%) in comparison with the "responders" (median 9.1%; range 6.7-11.9%; p=0.003). A significant negative correlation between the total GH secreted and the percentage of non-22 kDa isoforms was seen in the "non-responders" (p=0.003). These differences in GH response to repeated GHRH stimulation and in the pattern of GH isoforms at GH peak among subjects might be due to distinct recovery patterns of somatrotrophic function and/or differences in metabolic clearance of GH isoforms.

[Congenital solid tumors. A thirteen-year review]

Tumors diagnosed during the first month of life are infrequent: 0.5 to 2% of all childhood neoplasms. This is an interesting group of tumors because their type, relative incidence, natural history and response to treatment differ from those seen in older children.

AIM

To contribute the experience of our institution in congenital tumors the last 13 years.

MATERIAL AND METHODS

The records of all neonates (< 31 days old) diagnosed with solid tumors since January 1990 to December 2002 have been retrospectively reviewed.

RESULTS

Twenty-seven neonates have been diagnosed with tumors in the last 13 years. Thirteen patients (48%) were prenatally diagnosed. Nine babies were diagnosed at the initial neonatal exam (40% of those diagnosedd after birth). Neuroblastoma was the commonest tumor (10 cases, 37%), of which 4 were stage I, 4 stage IV-S and 2 stage III. There were 8 teratomas (3 sacrocoxigeal, 1 retroperitoneal, 1 in the CNS, 1 orbitary and two oronasal), two hepatic tumors (1 hepatoblastoma, 1 hemangioendothelioma, two CNS tumors, two giant nevus (one on a hamartoma), and one each Wilms tumor, infantile fibrosarcoma and myofibroblastic tumor. Treatment was surgical resection alone in 17 cases (68%) and surgery + chemotherapy in 8 (32%) (5 neuroblastomas, one CNS tumor, one Wilms tumor and one presacral teratoma who developed a yolk sac tumor); 3 patients died (11%): one at surgery, one of tumoural airway obstruction at birth and one with craniopharyngioma. Among the 14 tumors that were initially not malignant, two can be locally agressive, one was an immature teratoma, the giant nevus with hamartoma developed in situ melanoma, the other nevus had meningeal melanosis with hydrocephalus, and one mature presacral teratoma developed a yolk sac tumor.

CONCLUSIONS

Diagnosis of congenital tumors is performed earlier in recent years due to the wide use of prenatal ultrasound. Their natural history is more benign than in other age groups, except for CNS tumors and very large or obstructing tumors. The histological patern is not determinant of the outcome. Complete surgical excision is the treatment of choice, most cases not need adjuvant chemotherapy. We ought to pass this message on to our colleagues in prenatal diagnosis, so parents get reliable information.

Dual growth hormone (GH) response to repeated GH releasing hormone stimulus in children and adults

Several authors have demonstrated that plasma growth hormone (GH) levels as response to acute GH releasing hormone (GHRH) stimulation in adults are decreased by a previous GHRH injection whereas they are maintained in children. Probably the most accepted hypothesis for this finding is the increase in the somatostatinergic tone. The aim of the present study was to evaluate the dual GH response to repeated GHRH stimuli to clarify the possible influence of somatostatinergic activity in the type of response. Eighteen healthy prepubertal children, mean age 9.2 years (range: 6.0-12.9 years) and 19 healthy adult volunteers, mean age 25.5 years (range: 17-35 years) were studied with the GHRH test. An additional group of 10 normal adults with similar characteristics (mean age 31 years, range 25-35 years) were also recruited as a control group for somatostatinergic assessment. The GH response to the first GHRH bolus was similar in both children and adults. However, while children showed a preserved response to the second stimulus, it was diminished in adults. As expected, thyroid stimulating hormone (TSH) was within the normal range in all subjects. When the evolution of TSH was compared between the group of non-responders and the control group, no significant differences were found either at basal time or at 120 min, showing a similar decreasing trend for serum TSH level. The variation of TSH levels were also expressed as the proportion of TSH response after 2 hours compared to the basal level (TSH-120/TSH-0) but no significant differences were found (GHRH non-responders group mean: 73.6%, range: 51.3-93.7; control group mean: 70.7%, range: 62.9-92.5). In conclusion, the results confirm that in adults but not in children, the somatotrope responsiveness to GHRH is inhibited by a previous bolus of GHRH. The finding that the plasma TSH level diminishes in a similar manner in both non-responders and the control group is in agreement with the rejection of the hypothesis of the influence of somatostatin.

[GB virus C: lack of association with transaminases levels, CD4 and HIV viral load in aids patients]

OBJECTIVE

To study the prevalence of GBV-C-RNA in sera of HIV-infected patients and determine whether differences in immunological condition and hepatic disease exist between GBV-C positive and negative patients.

METHODS

The presence of GBV-C-RNA was determined in sera of 222 HIV-positive patients by semi-automated RT-PCR. A comparison of GBV-C-RNA positive and negative patients was made by studying a series of clinical and analytical parameters. This same comparison was made in particular between those coinfected with HCV and GBV-C and those who only presented GBV-C.

RESULTS

Prevalence of GBV-C-RNA was 28.8%. The most frequent hepatotropic virus was HCV, appearing in 71.6% of cases. Coinfection with HCV and HGV was present in 17% and 8.6% only had GBV-C. Patients positive for GBV-C-RNA showed clinical and analytical characteristics similar to those found in GBV-C-RNA negative patients. Among the HCV-GBV-C coinfected and those presenting HGV as the only virus it was observed that the coinfected group presented alterations in transaminases and predominance of parenteral transmission as a risk factor for HIV, whereas the GBV-C group presented normal transaminases and predominance of sexual transmission. No differences were perceived in mean CD4 and HIV-RNA values in both groups.

CONCLUSIONS

Being positive for GBV-C in HIV-positive patients does not influence the presence of hepatic disease that in these patients is frequently accompanied by coinfection with other hepatotropic viruses. Moreover, it does not seem to influence the viremia of the HIV nor the CD4 cell counts.