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Biomedical subjects

N Mendoza

Publications and source records attributed to N Mendoza.

At least 37 records · Page 2Linked to original sources

Lipid effects, effectiveness and acceptability of tibolone versus transdermic 17 beta-estradiol for hormonal replacement therapy in women with surgical menopause.

OBJECTIVE: To compare the effectiveness of tibolone and 17 beta-estradiol on climacteric symptoms, lipid and biochemical parameters in women with surgical menopause. METHODS: In a prospective randomised clinical trial group comparative study, the effects on the aforementioned parameters, as well as treatment compliance and side effects were studied with oral tibolone 2.5 mg per day and with transdermic 17 beta-estradiol at 50 microg per day for a period of 12 months. Statistical analysis was carried out using the Fisher-test, analysis of the variance (ANOVA) for the two factors and the Bouferoni test. RESULTS: Lipid metabolism analysis showed lower levels of HDL and triglycerides in the tibolone group. Other biochemical parameters were not affected. Similar reductions in climacteric symptoms were found in both the groups, but the tibolone group revealed a greater improvement in psychological problems and in sexual behaviour. No differences were observed with respect to compliance and side effects. CONCLUSIONS: Tibolone is as effective or more than 17 beta-estradiol in reducing climacteric symptoms, and shows greater triglyceride and total cholesterol improvements. Tibolone is a good alternative to estrogens in women with surgical menopause.

Administration, Cutaneous↗

Loss of chromosome 10 is an independent prognostic factor in high-grade gliomas.

Loss of heterozygosity (LOH) for chromosome 10 is the most frequent genetic abnormality observed in high-grade gliomas. We have used fluorescent microsatellite markers to examine a series of 83 patients, 34 with anaplastic astrocytoma (grade 3) and 49 with glioblastoma multiforme (grade 4), for LOH of chromosome 10. Genotype analysis revealed LOH for all informative chromosome 10 markers in 12 (35%) of patients with grade 3 and 29 (59%) grade 4 tumours respectively, while partial LOH was found in a further eight (24%) grade 3 and ten (20%) grade 4 tumours. Partial LOH, was confined to the long arm (10q) in six and the short arm (10p) in three cases, while alleles from both arms were lost in four cases. Five tumours (one grade 3 and four grade 4) showed heterogeneity with respect to loss at different loci. There was a correlation between any chromosome 10 loss and poorer performance status at presentation (chi2 P = 0.005) and with increasing age at diagnosis (Mann-Whitney U-test P = 0.034) but not with tumour grade (chi2 p= 0.051). A Cox multivariate model for survival duration identified age (proportional hazards (PH), P= 0.004), grade (PH, P= 0.012) and any loss of chromosome 10 (PH, P= 0.009) as the only independent prognostic variables. Specifically, LOH for chromosome 10 was able to identify a subgroup of patients with grade 3 tumours who had a significantly shorter survival time. We conclude that LOH for chromosome 10 is an independent, adverse prognostic variable in high-grade glioma.

Brain Neoplasms↗

Magnetic resonance imaging-compatible posterior cervical implant for occipitocervical stabilization. Technical note.

Posterior cervical stabilization was accomplished in 30 patients (19 females and 11 males) by using sublaminar titanium cables and a new titanium bullet-shaped implant. Seventeen patients underwent occipitocervical fixation and 13 others were treated subaxially. These patients have been followed for 18 to 52 months (mean 36 months), and no implant has failed during the follow-up period.

Adolescent↗

Motor evoked potential monitoring during spinal surgery: responses of distal limb muscles to transcranial cortical stimulation with pulse trains.

During spinal surgery, motor evoked potentials (MEPs) were recorded from distal upper and lower limb muscles following multipulse transcranial electrical stimulation of the cortex. Twenty-two patients, 9 of them myelopathic, were anaesthetised with propofol +/- nitrous oxide. Using trains of 3-6 pulses separated by 2 ms, consistent responses generally measuring more than 100 microV were obtained from every patient except one, and persisted with nitrous oxide concentrations as high as 74%. Responses could usually be elicited from 3 or more limbs simultaneously, although the location of the stimulating anode was sometimes critical. The lower limb responses of one patient disappeared transiently during excision of an intramedullary tumour; his leg weakness was increased for a few days after surgery. Three other patients experienced increased weakness or spasticity, two without concomitant MEP changes and one with no recordable responses. Although other methods may be preferable in some circumstances, we believe this represents an advance over previously reported non-invasive techniques for peroperative MEP monitoring, and may be particularly useful for monitoring patients with myelopathy in the thoracic region.

Adult↗

Arteriovenous malformations of the posterior fossa: a report on 28 cases and review of the literature.

Posterior fossa arteriovenous malformations are uncommon lesions accounting for between 7 and 18% of all intracranial arteriovenous malformations. They have a greater incidence of haemorrhage and a higher morbidity and mortality if untreated compared with those localized in the supratentorial compartment. We report our experience with 28 cases of posterior fossa arteriovenous malformations referred to the senior author between January 1971 and December 1993. The anatomy, symptomatology, treatment and results are discussed with regard to the most recent literature.

Adolescent↗

Dysphagia and deformity after undetected odontoid fracture in elderly patients.

Trauma in elderly patients is often difficult to evaluate and neck injuries are probably more common than is documented. A case is described of a missed odontoid peg fracture with the unusual presentation of dysphagia and a rapidly developing cervicodorsal kyphos (head falling forward), which may well have been anticipated at several points in the management chain. The lessons to be learned are outlined, together with the subsequent management of this patient.

Accidental Falls↗

Trigeminal neuralgia treated by microvascular decompression: a long-term follow-up study.

Since 1976, 133 patients treated by posterior fossa microvascular decompression (MVD) for trigeminal neuralgia (TN) have been followed-up prospectively to determine the incidence of recurrent TN. The follow-up period was between 6 months and 15 years, with 60 patients having been follow-up for more than 5 years. Of these patients, 71% have remained pain-free, while 29% have suffered a major or minor recurrence. Of patients who developed recurrent TN, 90% did so within 2 years of operation. No patients who were pain-free up to 5 years after operation subsequently developed recurrent TN. Recurrent TN was more likely to occur when the operative findings did not show nerve root distortion or displacement, or when the age of onset was less than 35 years.

Adolescent↗

Glomus jugulare tumours: a review of 61 cases.

A retrospective study of 61 patients with glomus jugulare tumours treated at the National Hospital for Neurology and Neurosurgery, and at the Royal National Throat, Nose and Ear Hospital, London. The average age at presentation was 41.7 years. The patients were mainly treated by a posterolateral combined otoneurosurgical approach. 42/61 of the patients had total or subtotal excision of their tumours, 7/61 had partial removal and the remaining 11/61 had no operation. Only one case required a 2-staged procedure. There were two deaths in the postoperative period, one from intracerebral haemorrhage and the other from the left hemisphere infarction. Postoperative radiotherapy was given to 5/7 of the patients who had partial removal. 3/40 of the patients with total removal had postoperative radiotherapy, and a further 3/40 had received radiotherapy pre-operatively. Of the 11 patients who did not undergo surgery, 7/11 were treated with radiotherapy and 4/11 had embolisation only.

Adult↗

Spontaneous spinal epidural haematoma: a cautionary tale.

Less than two hundred cases of spontaneous spinal epidural haematoma (SSEH) have been reported in the literature and theories as to its genesis are diverse. It is a serious condition, especially if there is a delay in diagnosis, as early treatment confers marked prognostic advantage. We present a case report of a 68-year-old male who was diagnosed as having a spinal epidural haematoma, followed by a discussion of the possible aetiology of this condition.

Aged↗

Aluminum.

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Aluminum↗

Absorption of aluminum from aceglutamide aluminum in healthy adult males.

The absorption of aluminum was studied in twelve healthy male volunteers over a period of fourteen days in a placebo-controlled, double blind study. All subjects were institutionalized during the study. Eight subjects (treated group) received ascending doses of aceglutamide aluminum (N-acetyl-L-glutamine aluminum complex) administered in multiple daily doses. The remaining four subjects (untreated group) received placebo. Systemic absorption and excretion of aluminum were evaluated by measuring aluminum concentrations in serum, urine and fecal samples. Aluminum concentrations were determined by electrothermal atomic absorption spectrometry. All serum aluminum concentrations were less than 16 micrograms/L for both groups. The mean urinary and fecal aluminum concentrations in the aluminum-treated group were significantly higher than in the untreated group during the study days the drug was administered. The total amount of aluminum (as aceglutamide aluminum) given to each treated subject during the 14 day study period as 3290 mg. The mean total fecal aluminum concentration was 3318 mg for the treated group and 269 mg for the untreated group during the study period. These findings are consistent with the view that some aluminum absorption from the gastrointestinal tract occurred following the administration of the drug. The absorbed aluminum appears to have been rapidly excreted in the urine and the feces.

Adolescent↗

Recurrence of diabetic nodular glomerulosclerosis in a renal transplant.

A 36-year-old woman with a 26-year history of insulin-dependent diabetes mellitus developed chronic renal failure in 1974 and was started on dialysis. She received a kidney transplant from her HLA-identical brother. Her HLA typing showed the following antigens: A1, A28, B8, B12 (44), BW4, BW6 DR3, and DR4. Nephrectomy performed prior to transplantation showed advanced diffuse diabetic glomerulosclerosis. Her postoperative course was relatively uncomplicated, but within the next seven years she gradually developed symptoms of deteriorating renal function and hypertension. Two years later, a renal arteriogram showed 90% stenosis of the main renal artery. Biopsy of the kidney was obtained during surgical repair of this lesion and showed diffuse nodular diabetic glomerulosclerosis. Since the B8/DR3 form of diabetes is reported to have a predilection for diabetic microangiopathy and vascular complications, we are speculating that the patient's antigenic composition might have enhanced the recurrence of the diabetic lesions in the transplanted kidney.

Adult↗

Membranous glomerulopathy following kidney transplantation. Association with renal vein thrombosis in two of nine cases.

The association of renal vein thrombosis and membranous glomerulopathy in native kidneys has been well documented. However, this association has only occasionally been described following renal transplantation. A review of 693 renal transplant recipients revealed 77 (11%) in whom persistent, heavy proteinuria (greater than 2 g/24 hr) developed. Renal histology was available in all 77 patients. A diagnosis of membranous glomerulopathy was made in 7 patients. Two further cases were added on the basis of biopsy findings--1 patient had a protein excretion of 1.7 g/24 hr, the other had microscopic hematuria and red cell casts in the urine. Renal venography was performed in 4 cases. The decision to perform venography was based on clinical criteria (thrombophlebitis or marked edema of the leg on the side of the allograft), and/or histological criteria (associated interstitial edema and venous congestion). Renal vein thrombosis was present in 2 patients. Three of the 9 patients had membranous glomerulopathy as the cause of their end-stage renal disease; 2 of these patients had received kidneys from living-related donors. Four of the patients were classified as having de novo membranous glomerulopathy on the basis of having a different cause for their end-stage renal disease. Two patients were classified as having unspecified membranous glomerulopathy; both of these patients had had chronic glomerulonephritis, but there was lack of characterization of the original glomerular disease. Seven of the 9 patients continued to have stable allograft function 1-12 months after the diagnosis of membranous glomerulopathy was made in the renal allograft. The remaining 2 patients both had associated renal vein thrombosis; 1 had progressive deterioration of renal function and returned to dialysis 24 months after the diagnosis of membranous glomerulopathy had been made, while the other died of unrelated causes 27 months after the diagnosis had been made.

Adult↗