A new approach for initial callus growth during fracture healing in long bones.

The incidence of bone fracture has become a major clinical problem on a worldwide scale. In the past two decades there has been an increase in the use of computational tools to analyse the bone fracture problem. In several works, various study cases have been analysed to compare human and animal bone fracture healing. Unfortunately, there are not many publications about computational advances in this field and the existing approaches to the problem are usually similar. In this context, the objective of this work is the application of a diffusion problem in the model of the bone fragments resulting from fracture, working together with a mesh-growing algorithm that allows free growth of the callus depending on the established conditions, without a pre-meshed domain. The diffusion problem concerns the different biological magnitudes controlling the callus growth, among which Mesenchymal Stem Cells and chondrocytes concentrations were chosen, together with Tumour Necrosis Factor α and Bone Morphogenetic Protein as the factors influencing the velocity in the callus formation. A Finite Element approach was used to solve the corresponding diffusion problems, obtaining the concentration values along the entire domain and allowing detecting the zones in which biological magnitudes reach the necessary thresholds for callus growth. The callus growth is guided by a geometrical algorithm which performs an additional mesh generation process (self-added mesh) at each step of the iterative procedure until complete callus formation. The proposed approach was applied to different types of diaphyseal femoral fractures treated by means of intramedullary nailing. Axisymmetric models based on triangular quadratic elements were used, obtaining results in good agreement with clinical evidence of these kinds of fractures. The algorithm proposed has the advantage of a natural callus growth, without the existence of a previous mesh that may affect the conditions and direction of growth. The approach is intended for the initial phase of callus growth. Future work will address the implementation of the corresponding formulations for tissue transformation and bone remodelling in order to achieve complete fracture healing.

[Magnesium in cerebrospinal fluid in acute cerebral ischemia: its relation to glutamate neurotoxicity]. / Magnesio en líquido cefalorraquídeo en la isquemia cerebral aguda: relación con la neurotoxicidad por el glutamato.

INTRODUCTION: In animal models it has been shown that there is an increase in tissue magnesium concentration during cerebral ischemia. We studied the changes in magnesium levels in the cerebrospinal fluid (CSF) during the acute phase of cerebral ischemia. MATERIAL AND METHODS: We included 95 patients with first ischemic cerebral infarcts admitted to hospital within the first 24 hours and also 37 controls. CT scan was done on admission and between four and seven days later (when the volume of the infarct was determined). The neurological defect was evaluated on the Canadian scale on admission, after 48 hours, on the seventh day and after three months. The CSF magnesium concentration was determined using a colorimetric method and the glutamate by HPLC. RESULTS: The CSF magnesium concentrations were significantly higher in the patients than in the controls (2.6 +/- 0.6 mmol/l vs 2.2 +/- 0.6 mmol/l p = 0.0001). The magnesium concentration was higher in the larger infarcts (Pearson's coefficient = 0.2901, p = 0.0043), and in those presenting greater neurological defects after 48 hours (Spearman's coefficient = -0.4649, p < 0.0001). The magnesium concentration was not related to the presence of early signs on the initial CT scan and the Canadian scale rating on admission. The concentration of magnesium was significantly correlated with that of glutamate (Pearson coefficient = 0.7735, p < 0.0001). CONCLUSIONS: The levels of magnesium in the CSF were satisfactorily related to the volumes of the infarct and the intensity of the neurological defect. However, this association was late, occurring more than 48 hours after onset of the condition.

[The prognostic value of analytical hemorheological factors in stroke]. / Valor pronóstico de factores analíticos hemorreológicos en el ictus.

Plasmatic hyperviscosity is a known vascular risk factor which depends, among other parameters, upon total proteins, haematocrit value and fibrinogen. The aim of this study was to determine the relationship between these analytical haemorrological parameters and mortality and acute stroke sickness rate. We studied 216 patients with brain infarct and spontaneous intracerebral haemorrhage out of a sample of 256 acute stroke patients. We evaluated neurological affectation using the Canadian scale upon admission, on the seventh day and after three months. We determined plasmatic haemorrological factors (haematocrit, fibrinogen and total proteins) upon admission and again after one week and then at three months High fibrinogen levels in plasma were related to brain infarct mortality regardless of the cause of death.

[Time for cerebral damage due to hyperglycemia in acute ischemia]. / Tiempo para el daño cerebral por hiperglucemia en la isquemia aguda.

INTRODUCTION: Hyperglycemia increases morbimortality in cerebral infarcts. In animal models, this relationship is only seen during the initial moments of cerebral ischaemia. The time needed in humans for cerebral damage to occur due to hyperglycemia is not known. MATERIAL AND METHODS: We included 194 patients admitted within 24 hours of the start of their first clinical episode of cerebral hemisphere infarction. The glucemia was determined on admission and after 24, 48 and 72 hours. The neurological defect was evaluated on the Canadian scale on the seventh day. The volume of the infarct was determined on a second CT scan done between the fourth and seventh days after the episode. RESULTS: There was a positive association between the volume of the infarct and the glycemias on admission and after 24 hours, but this was not seen in later determinations. The difference in scoring, on the Canadian scale, on the seventh day, between patients with glycemias above or below 120 mg/dl decreased from the time of admission up to the time samples were taken 72 hours later. However, statistical significance persisted during the whole period studied. Nevertheless, in a logistic regression model, the glycemia on admission was the only determination associated with the Canadian scale on the seventh day (OR = 1.02; IC 95% = 1.01-1.02). CONCLUSIONS: There is a clear association between hyperglycemia and the worst stage of the infarct, and this is most intense in the first hours after onset of the clinical features.

[The prognostic value and evolution of blood pressure during an acute phase of stroke]. / Valor pronóstico y evolución de la tensión arterial en la fase aguda de la enfermedad cerebrovascular.

We studied the prognostic influence and evolution of blood pressure during the acute phase of stroke in 89 patients (50 men and 39 women) with an average age of 69.4 +/- 10.8 years. Seventy-two were diagnosed as having ischaemic infarct and 17 as having spontaneous intracerebral haemorrhage. Blood pressure was taken every four hours for twelve days. Clinical situation was evaluated using the Rankin scale. Systolic and diastolic blood pressure progressively decreased without needing any medication in the first two weeks of evolution. The decrease was greatest in hypertense patients and in those with left ventricle hypertrophy. We found the initial figures for systolic and diastolic blood pressure significantly higher in those patients with brain infarct who had not died and in those in a better functional position the second week of evolution. Blood pressure did not influence the prognosis of intracerebral haemorrhage patients.

[Epidemiological study of tuberculosis in the health area of Santiago de Compostella in 1992, 1993 and 1994]. / Estudio epidemiológico de la tuberculosis en el área sanitaria de Santiago de Compostela durante 1992, 1993 y 1994.

An exhaustive search for the clinical records of patients diagnosed with tuberculous disease was done in the hospitals of the area under study, which involves 392,000 population. During the years 1992, 1993 and 1994. There were included: 1) patients who had positive bacilloscopy and/or positive Lowenstein's culture in any specimen: 2) patients younger than 35-years-old who had pleural effusion, significant Mantoux and adenosine deaminase (ADA) over 47 U/I in the pleural effusion. In total 814 patients remained in the study with an average age of 38.39(19.39 DE) in 1992, 39.02 (20.04 DE) in 1993, and 34.1 years-old (19.2 DE) in 1994, with extreme ages of 2 months and 87 years-old. The incidence/100,000 H was: in 1992: 67.86, in 1993: 66.58 and in 1994: 73.2. The contagious forms incidence/100,000 H was: 1.5 in 1992 and 1993; and 1.79 in 1994. The hospital mortality incidence/100,000 H was 2.04 in 1992, 2.30 in 1993 and 2.6 in 1994. We conclude that tuberculosis is endemic in our area with moderately high and stationary incidence.

[Diltiazem in esophageal motility disorders]. / Diltiazem en los trastornos de la motilidad esofágica.

The effects of the calcium blocking agent diltiazem upon esophageal motility was studied with electromanometric technique in 23 patients. In 10 achalasic patients lower esophageal sphincter pressure was reduced in 40.1%, in the remaining 13 in only 19.15%. Other parameters showed only minor changes such as reduction in the pressure of contractile waves in the body of the esophagus.

[Clinico-manometric correlation in esophageal involvement of progressive systemic sclerosis]. / Correlación clínico-manométrica en el compromiso esofágico de la esclerosis sistémica progresiva.

The esophageal response studied in the systemic illness has been developed clearly in the body of the esophagus as well as in the lower esophageal sphincter, showing important alterations in the peristalsis and a significant fall of lower esophageal sphincter pressure, proving conditions such as those in which gastro-esophageal reflux is produced. The authors studied the esophageal motility in 10 patients with progressive systemic sclerosis by electromanometry by means of an open-tipped catheters system. They found that the pressure of the inferior esophageal sphincter was altered in the 100 per cent of the cases; in 50% of the patients there was a lack of peristaltic waves and in the remaining 50% the middle pressure was less than in normal subjects. It was observed dysquinethic waves in 40% of the cases. The intensity of the epidermic compromise is no related with alterations in the esophageal functioning.

Neuroexcitatory amino acids and their relation to infarct size and neurological deficit in ischemic stroke.

BACKGROUND AND PURPOSE: The participation of excitatory amino acids (EAAs) in the pathogenesis of ischemic neuronal lesion has been experimentally demonstrated, but clinical experience is scarce. Our objective was to examine EAA levels during the acute phase of cerebral infarction in relation to infarct size and intensity of neurological deficit. METHODS: Using high-performance liquid chromatography, we determined the glutamate, aspartate, taurine, and glycine concentrations in the plasma and cerebrospinal fluid (CSF) of 128 patients with ischemic cerebral infarction confirmed by CT and 43 control subjects. Blood and CSF samples were obtained on admission within the first 24 hours from symptom onset. The severity of the neurological deficit was assessed with the Canadian Stroke Scale immediately after these tests and at 48 hours after inclusion in the study. Infarct volume was determined in a second CT performed between the 4th and 7th day after the patient's inclusion. RESULTS: The concentration of plasmatic glutamate was 121.39 +/- 80.89 mumol/L in the control group and 163.71 +/- 103.13 mumol/L in the patient group (P = .015); in CSF it was 3.46 +/- 1.20 mumol/L in control subjects and 6.55 +/- 4.65 mumol/L in patients (P < .0001). The concentration of glycine in plasma was 158.02 +/- 32.15 mumol/L in control subjects and 189.37 +/- 74.04 mumol/L in patients (P = .007); in CSF it was 6.18 +/- 2.28 mumol/L in control subjects and 11.23 +/- 6.96 mumol/L in patients (P < .0001). The concentrations of glutamate in plasma and in CSF were significantly higher in patients with large cerebral infarcts and in those with cortical infarcts. Levels of glutamate and glycine in plasma and CSF were significantly higher in patients with a higher degree of neurological deficit. CONCLUSIONS: Our results support the excitotoxic activity of glutamate and glycine in patients with cerebral infarction.

Cerebrospinal fluid tyrosine and 3,4-dihydroxyphenylacetic acid levels in migraine patients.

We studied biochemical parameters related with central dopaminergic neurotransmission in migraine patients during crisis. We determined tyrosine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in cerebrospinal fluid (CSF) of 47 patients, 29 suffering migraine without aura and 18 suffering migraine with aura, comparing them with 27 control subjects. Tyrosine levels did not differ significantly between patients and controls. The CSF concentration of DOPAC was 0.73 +/- 0.55 ng/ml in the control population, 3.84 +/- 2.08 ng/ml in patients with migraine without aura and 3.30 +/- 1.49 ng/ml in patients suffering migraine with aura. The concentration of DOPAC correlated positively with the intensity of headache. These results suggest that patients with migraine have a central dopaminergic hyperfunction, probably related to a coexisting central dysfunction of noradrenergic neurotransmission.

Diltiazem en los trastornos de la motilidad esofagica. / Diltiazem in esophageal motility disorders

Los efectos del bloqueante calcico "diltiazem" fueron estudiados mediante electromanometria esofagica en 23 pacientes.En los enfermos de acalasia se observo una reduccion de la presion del esfinter esofagico inferior del 40.1% mientras que en el resto del grupo fue del 19.15%. Los otros parametros estudiados sufrieron variaciones menores como, por ejemplo reduccion en la presion de ondas contractiles del cuerpo del esofago

Estudio sobre la profilaxis de la infeccion quirurgica con monodosis de antibioticos. / Prophylaxis of the surgical infection with monodoses of antibiotics

Se realizo un estudio prospectivo randomizado en 118 pacientes para probar la utilidad de la antibioticoterapia profilactica de la infeccion quirurgica en operaciones "limpias". Se utilizo un esquema original con monodosis preoperatoria inmediata de gentamicina y cefalotina. Se demuestra estadisticamente la reduccion en las complicaciones septicas de la herida operatoria en el grupo tratado. No se observaron otro tipo de complicaciones que las de la herida. En ningun caso estas fueron severas

Correlacion clinico-manometrica en el compromiso esofagico de la esclerosis sistemica progresiva. / Clinico-manometric correlation in the esophageal involvement of progressive systemic sclerosis

La repercusion esofagica de la enfermedad sistemica estudiada se manifesto muy claramente, tanto en el cuerpo del organo como en el esfinter inferior, caracterizando importantes alteraciones en la peristalsis y una significativa reduccion en la presion del esfinter inferior, determinante de condiciones tales como aquellas en las que se produce reflujo gastro-esofagico