Biomedical subjects

J J Nauta

Publications and source records attributed to J J Nauta.

At least 37 records · Page 2Linked to original sources

PubMed1993

Spironolactone in congestive heart failure refractory to high-dose loop diuretic and low-dose angiotensin-converting enzyme inhibitor.

Patients with severe congestive heart failure (New York Heart Association [NYHA] functional classes III-IV) often can tolerate only low doses of angiotensin-converting enzyme (ACE) inhibitors because pronounced hypotension caused by additional ACE inhibitor increments may decrease renal perfusion. The use of high-dose loop diuretics is currently advised to overcome diuretic resistance in refractory congestive heart failure (CHF). In a baseline controlled study, we evaluated 21 patients with diuretic resistance and evident fluid retention for the responses to 5 days of double drug therapy consisting of high-dose loop diuretic (10 mg oral bumetanide) in combination with the maximum tolerable dose of an ACE inhibitor (individualized to blood pressure and kidney function). Five patients (24%) showed a gross natriuresis and reduction in excess weight > 25% in response to this therapy. The remaining 16 patients (76%) with insufficient responses (i.e., < 25% reduction in excess weight) subsequently received 100 mg spironolactone once a day for 7 days in addition to the double therapy. Spironolactone coadministration was highly effective in 13 of 16 patients (81%). Marked natriuresis and diuresis were achieved within the next week of treatment, and CHF symptoms regressed or disappeared. The clinical course was similar in the bumetanide-ACE inhibitor and the bumetanide-ACE inhibitor-spironolactone treatment (triple therapy) groups. Plasma aldosterone was significantly higher (p < 0.05) in the patients who needed spironolactone. The 3 patients who were considered refractory to triple therapy exhibited the highest baseline plasma aldosterone concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Regional lymph node involvement and its significance in the development of distant metastases in head and neck carcinoma.

BACKGROUND: The incidence of distant metastases in head and neck cancer patients is rising because of greater locoregional control of the disease. METHODS: The relative risks for having distant metastases as first site of failure relative to the regional lymph node involvement were determined. RESULTS: The overall incidence was 10.7%, with a clear relationship between the number of involved lymph nodes and extranodal spread on one hand, and distant spread on the other hand. The group with histopathologic presence of disease in the neck had twice as much distant metastases as did those with histopathologic absence (13.6% versus 6.9%). Patients with more than three histologically positive lymph nodes were most at risk for having distant metastases (46.8%). The presence of extranodal spread meant a threefold increase in the incidence of distant metastases, compared with patients without this feature (19.1% versus 6.7%). CONCLUSIONS: Patients with three or more positive nodes and with extranodal spread may benefit from adjuvant systemic therapy.

Adult↗

PubMed1993

Database for serial magnetic resonance imaging in multiple sclerosis.

The unique sensitivity of magnetic resonance imaging (MRI) in detecting disease activity in multiple sclerosis (MS) and the objective nature of the information obtained suggest that MRI will be a useful and reliable way of monitoring treatment trials. There is a need to develop an appropriate database which would provide a standardised means of assessment, not only of MRI, but also of essential clinical information. As part of the program of Concerted Action in Multiple Sclerosis, funded by the Commission of the European Community (CEC), we have developed a database for recording serial brain MRI results. The database consists of core, entry and follow-up sections. Both entry and follow-up parts are subdivided into clinical, MR system and MRI data. We expect that the use of this database will maximise efficiency of MRI monitoring in MS treatment trials, particularly in multicentre studies.

Brain↗

PubMed1993

A semiquantative rating scale for the assessment of signal hyperintensities on magnetic resonance imaging.

Differences in grading signal hyperintensities on magnetic resonance imaging may explain earlier reported conflicting results in studies of normal aging and dementia. We designed a new rating scale in which periventricular and white matter signal hyperintensities as well as basal ganglia and infratentorial signal hyperintensities are rated separately in a semiquantative way. In this study we compared the inter- and intra-observer agreements of this scale to the widely used rating scale of Fazekas. We confirmed the poor to reasonable intra- and inter-observer agreements of the Fazekas scale. The new scale, although more elaborate, provided good agreements with respect to the white matter, basal ganglia and infratentorial signal hyperintensities. In rating periventricular hyperintensities this scale yielded no advantage. It is concluded that this scale may be of use in studies especially focussing on deep white matter pathology on MRI, because it provides more detailed information, with good intra- and inter-observer reliability.

Aged↗

PubMed1993

4-Aminopyridine induces functional improvement in multiple sclerosis patients: a neurophysiological study.

This study reports on the neurophysiological measurements that were performed in the context of a randomized, double-blind, placebo-controlled, cross-over study with intravenously administered 4-aminopyridine (4-AP) in 70 patients with definite multiple sclerosis (MS). A beneficial effect of 4-AP was found for both visual evoked response and eye movement registration parameters. This study extends the experimental data obtained on animal nerve fibers, showing that 4-AP can improve impulse conduction in demyelinated nerve, to clinical data which indicate that 4-AP induces an objective improvement in the central nervous system function in MS-patients. It thereby also provides a theoretical basis for clinical efficacy of 4-AP in MS.

4-Aminopyridine↗

PubMed1993

Adhesive capacity of human long-term bone marrow cultures from normals and patients with acute myeloid leukaemia: the influence of adhesion molecules.

In order to study the adhesive interactions of the human bone marrow microenvironment and acute myeloid leukaemic cells, we investigated the binding capacity of KG-1 cells upon human long-term bone marrow cultures derived from 17 healthy volunteers and 12 patients with acute myeloid leukemia. Adhesion was measured using a 51-chromium labelling assay. Adhesion of KG-1 cells upon 'normal' stromal layers: 33% +/- 4.0, n = 17 (mean +/- SEM) was higher as compared to the binding to 'leukaemic' stromas: 24% +/- 3.7, n = 12 (p < 0.05). Blocking monoclonal antibodies against adhesion molecules reduced the binding of KG-1 cells upon 'normal' stroma, when anti-VLA4 (p < 0.03), anti-Mac1 (p < 0.03) and anti-p150/95 (p < 0.04) were used. Binding of KG-1 cells on 'leukaemic' stromas was partly inhibited by anti-VCAM1 (p < 0.03). Blocking achieved by single or combined antibodies was never complete, suggesting that the adhesion is a multifactorial process, including a variety of adhesion molecules and/or adhesion mechanisms.

Acute Disease↗

PubMed1993

Cortical laminar abnormalities--occurrence and clinical significance.

Cortical laminar necrosis is a histopathological entity, related to conditions of cerebral energy depletion. Clinical correlates are supposed to be spastic motor deficits, decreased intellectual capacity and epilepsy. A study was performed in 45 children with cortical laminar abnormalities in signal intensity on MRI. The purpose of the study was to evaluate causes and clinical consequences of these cortical abnormalities on MRI in order to find indirect evidence for the hypothesis that they may represent cortical laminar necrosis. In view of the frequently present concomitant white matter damage, two contrast groups were formed: one group of 40 children with periventricular white matter abnormalities, part of them with subcortical extensions of the white matter damage; and another group of 53 children without abnormalities on MRI. Data concerning history, present clinical condition and final diagnosis were collected. The presence of cortical laminar abnormalities on MRI was found to be strongly associated with a history of cerebral energy depletion, especially hypoxia-ischemia, either in the perinatal period or later in life. Whereas white matter abnormalities tended to be more frequent in premature children, cortical laminar abnormalities tended to occur more frequently in term neonates and older children. The presence of cortical laminar abnormalities on MRI was correlated with an increased risk of spasticity in children without concomitant white matter abnormalities. In children with white matter lesions, cortical laminar abnormalities did not contribute to the risk of spasticity, which was already highly increased by the presence of white matter damage. No association was found between cortical abnormalities on MRI and epilepsy or psychomotor retardation.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Diseases↗

PubMed1993

Gadolinium enhancement increases the sensitivity of MRI in detecting disease activity in multiple sclerosis.

There is now widespread agreement that serial brain MRI is useful in monitoring treatments designed to modify the course of multiple sclerosis. It has been less clear whether gadolinium enhancement is needed. We therefore compared the relative sensitivity of long repetition time (TR) spin echo (SE) and gadolinium enhanced short TR SE sequences in detecting active lesions. A blind analysis of the two sequences was performed in 26 untreated patients with early relapsing--remitting (19) or secondary progressive (seven) multiple sclerosis who underwent monthly MRI on four occasions (one baseline and three follow-up). Active lesions were defined as either new or enlarged lesions on long TR SE, or new or persistent enhancing lesions on short TR SE. In one patient there were 144 active lesions, all of which were seen with enhancement on short TR SE, but only 17 were seen on long TR SE. Amongst the remaining 25 cases, a total of 106 active lesions were seen: 68 (64%) were seen only with enhancement on short TR SE, 16 (15%) were seen only on long TR SE, while 22 (21%) were active on both sequences. We conclude that gadolinium enhancement markedly increases the sensitivity of monthly brain MRI in monitoring the treatment of relapsing--remitting or secondary progressive multiple sclerosis. With this frequency of scanning, a post contrast short TR SE sequence is the most sensitive method for detecting active lesions. The smaller yet still substantial incidence of active lesions seen only on the long TR SE sequence suggests that it should also be obtained.

Adult↗

PubMed1993

4-Aminopyridine in patients with multiple sclerosis: dosage and serum level related to efficacy and safety.

In a recent randomized, double-blind, placebo-controlled crossover trial, we demonstrated efficacy of 4-aminopyridine (4-AP) in improving disability of patients with multiple sclerosis (MS). Here we describe the relationship between dosage, serum level, efficacy, and safety of intravenously and orally administered 4-AP in the same group of 70 MS patients. After both intravenous and oral administration there was a significant relationship between serum levels and 4-AP doses used (p < 0.001 and p < 0.01, respectively). The use of 4-AP in oral doses three times a day showed a large variation and fluctuation in serum levels. After 12 weeks of oral treatment (maximum daily dosage 0.5 mg/kg body weight), a statistically significant improvement was found for the smooth pursuit gain of the eye movements (estimated effect 0.14, 95% confidence interval 0.06-0.23, p < 0.001). The amount of improvement was significantly related to 4-AP serum levels (p = 0.0013). Side effects after intravenous 4-AP occurred frequently and were very troublesome (pain in infusion arm, dizziness). Side effects during oral treatment (dizziness, paresthesias) were very mild and occurred 30-45 min after intake of the medication and could be related to high serum levels.

4-Aminopyridine↗

PubMed1993

Serum antineutrophil cytoplasmic autoantibodies in inflammatory bowel disease are mainly associated with ulcerative colitis. A correlation study between perinuclear antineutrophil cytoplasmic autoantibodies and clinical parameters, medical, and surgical treatment.

Perinuclear antineutrophil cytoplasmic antibodies have recently been demonstrated in the sera of patients with inflammatory bowel disease. Three hundred and sixty six sera obtained from 120 patients with ulcerative colitis, 105 patients suffering from Crohn's disease and 49 non-inflammatory bowel disease controls were tested in two laboratories, using an indirect immunofluorescence assay. In addition, a fixed-neutrophil enzyme linked immunoadsorbent assay (ELISA) was evaluated in one of the two laboratories. The results in the immunofluorescence test showed a high degree of correlation between the two laboratories (Kappa coefficient = 0.8). Ninety five of the 120 (79%) ulcerative colitis patients had a positive test whereas only 14 of the 105 (13%) patients with Crohn's disease were positive. Sera from four patients suffering from primary sclerosing cholangitis were positive as well as four of the 45 control sera (9%). The sensitivity of the perinuclear antineutrophil cytoplasmic antibody immunofluorescence test for the diagnosis of ulcerative colitis was 0.75 with a specificity of 0.88 and a positive predictive value of 0.88 (all sera). In the ELISA technique 37 of 94 ulcerative colitis sera and one of the 68 Crohn's disease sera were positive. In the control group only one of the patients suffering from primary sclerosing cholangitis reacted positively (32 non-inflammatory bowel disease sera tested). The ELISA technique had a high specificity (0.97), but a low sensitivity (0.39). There was no relation of perinuclear antineutrophil cytoplasmic antibodies in ulcerative colitis patients or in Crohn's disease patients with disease activity, duration of illness, localisation, extent of disease, previous bowel operations or medical treatment. The clinical significance of perinuclear antineutrophil cytoplasmic antibody positive and negative subsets in both groups of patients thus remains unexplained. Our study confirms that determination of serum antineutrophil cytoplasmatic antibodies in patients with inflammatory bowel disease may differentiate ulcerative colitis from Crohn's disease. Further immunological studies are needed to explain the absence of these antibodies in a subset of ulcerative colitis patients and their role in the pathogenesis of the disease.

Adult↗

PubMed1993

The pharmacodynamics and activity of intranasally administered insulin in healthy male volunteers.

The objective of the study was to assess the bioavailability and absorption dynamics of intranasal insulin (with di-decanoyl-alpha-phosphatidylcholine, DDPC, as absorption enhancer) in two potencies (U200 and U500). Toward this aim, the euglycemic clamp technique combined with somatostatin (100 micrograms/h) was used. Insulin was administered to 12 healthy males: 5 IU intravenously (20-min infusion); 10 IU subcutaneously; 50 IU (U200) and 50 IU, 100 IU, and 150 IU (U500) intranasally. Peak insulin levels (mean +/- SD) were reached at 17.9 +/- 2.6, 77.9 +/- 38.3, 23.3 +/- 5.4, 25.4 +/- 8.4, 26.2 +/- 8.3, and 27.5 +/- 5.8 min, respectively. For the 50 IU dose, peak glucose requirements during the clamp and time to peak were not significantly different for U200 and U500: 548.8 +/- 279.5 vs. 452.4 +/- 232.9 mg/min and 41.3 +/- 16.2 vs. 51.5 +/- 29.9 min, respectively. Compared with intravenous insulin, the bioavailability calculated from the total area under the insulin curve was 13.2% (95% confidence interval 7.9, 21.9) and 8.8% (95% confidence interval 5.6, 13.8), and compared with subcutaneous insulin, the bioavailability was 14.8% (95% confidence interval 8.7, 25.2) and 9.9% (95% confidence interval 6.4, 15.4) for the U200 and U500 preparations, respectively. An apparent nonlinear dose-dependent relation was found for the U500 potency. The within-subject variability of the areas under the curves of plasma insulin after the administration of 100 IU was 43.6% (range 20.7-85.7). In conclusion, this nasal insulin preparation has promising absorption and action profiles in both potencies, which makes it suitable for further exploration of clinical applications.

Administration, Intranasal↗

PubMed1993

Risk factors for multiple organ system failure and death in critically injured patients.

BACKGROUND: This study was undertaken to evaluate the relative importance of factors related to the extent of multiple organ system failure (MOSF) and outcome in critical trauma. METHODS: We performed a retrospective case series analysis of 206 consecutive patients with trauma admitted to a surgical intensive care unit during a 5-year period. Multivariate methods were used to select independent factors related to the MOSF score and subsequent death. RESULTS: Multiple linear regression selected advancing age, prior chronic conditions, malnutrition, injury severity score (ISS), coma on admission, use of H2-receptor antagonists or antacids, number of blood transfusions, and intraabdominal infection as independent factors related to the MOSF score. Multiple logistic regression selected advancing age, chronic disease, ISS, and MOSF score as major predictors of death. CONCLUSIONS: Advancing age, prior chronic disease, malnutrition, coma on admission, and use of H2-receptor antagonists or antacids may impair host defenses of the gastrointestinal tract and predispose to invasive infection, thereby aggravating the severity of existing MOSF. These findings, together with the predominance of Enterobacteriaceae in patients with infection, suggest that bacterial translocation may be important in the late MOSF septic state. Although infection, particularly intraabdominal infection, is a major risk factor for MOSF, a nonspecific host response to critical trauma, as expressed by the ISS and transfusion requirement, and intestinal endotoxin may contribute to the development of the syndrome.

Adolescent↗

PubMed1993

Vasodilating prostaglandin E1 decreases critical oxygen delivery by increasing critical oxygen extraction in anesthetized pigs.

The abnormal dependence of O2 uptake (VO2) on O2 delivery (QO2) during severe sepsis, and the adult respiratory distress syndrome (ARDS) may be caused by impaired vascular reactivity, following release of vasodilating prostaglandins. Infusion of these compounds, however, may improve tissue oxygenation. We studied the effect of vasodilating prostaglandin E1 (PGE1; 0.2 microgram/kg/min) on the critical O2 extraction ratio (ERO2c) and the critical QO2 (QO2c) in a saline-controlled, crossover study in 12 barbiturate-anesthetized pigs. QO2, VO2 (independently from QO2), and blood lactate concentrations were measured during graded cardiac output reductions by incremental positive end-expiratory pressure (0-20 cm H2O PEEP, raised by 5 cm H2O at 15 min intervals). At 0 cm H2O PEEP, PGE1 decreased arterial blood pressure, mainly due to a fall in systemic vascular resistance. From 0 to 20 cm H2O PEEP, the fall in QO2 was greater in the PGE1 than in the saline series (P < 0.005), since ventricular filling and the rise in heart rate were less in the former. The decrease in VO2 (P < 0.005) did not differ between series. As estimated from bilinear regression on paired VO2/QO2 data in individual pigs, the QO2c was 9.8 +/- 3.6 (mean +/- SD) during PGE1 and 14.6 +/- 3.8 ml/kg/min during saline infusion (P = 0.008), with ERO2c 68% +/- 16% and 48% +/- 12%, respectively (P < 0.005). The QO2c, estimated from bilinear regression on paired lactate/QO2 data during the first treatment period, was 7.1 +/- 1.2 for PGE1 and 12.8 +/- 4.5 ml/kg/min for saline (P < 0.05), at similar lactate concentrations (2.0 +/- 0.5 and 1.7 +/- 0.5 mmol/liter, respectively). PGE1-induced vasodilation thus decreases QO2c, because of increased ERO2c, probably resulting from capillary recruitment, an increased surface area available for O2 exchange, and decreased O2 diffusion distances. Hence, a reduced ERO2 and abnormal supply dependence of VO2 during severe sepsis and ARDS are not caused by release of vasodilating prostaglandins. In contrast, our results partly explain improved tissue oxygenation with these compounds during abnormal VO2 supply dependence, following sepsis and ARDS.

Alprostadil↗

PubMed1992

Urinary albumin excretion, cardiovascular disease, and endothelial dysfunction in non-insulin-dependent diabetes mellitus.

Raised urinary albumin excretion (UAE) is associated with an increased risk of cardiovascular disease in non-insulin-dependent diabetes mellitus (NIDDM). We have examined the role of endothelial dysfunction as a possible explanation for this association in 94 NIDDM patients by investigating UAE, new cardiovascular events, and plasma concentration of von Willebrand factor (vWF), an indicator of endothelial dysfunction. At baseline, 66 patients had normal UAE (less than 15 micrograms/min), which remained normal in 33 (group 1) and increased in 33 (to median 31.5 micrograms/min, group 2). In 28 patients, baseline UAE was abnormal (67.1 micrograms/min, group 3). Follow-up ranged between 9 and 53 months. vWF did not change in group 1 (median 128% at baseline and 123% at follow-up), but increased in group 2 (from 116 to 219%, p less than 0.0001) and group 3 (from 157 to 207%, p = 0.0005). Baseline level of and change in vWF were strongly related to the development of microalbuminuria (R2 = 0.60, p less than 0.0001), but cardiovascular risk factors were not (R2 = 0.14). Raised baseline UAE was associated with an increased risk of new cardiovascular events only in patients with vWF concentrations above the median (relative risk 3.66, 95% CI 1.3-11.9) and not in patients with lower vWF (0.19, 0.01-1.33). In addition, the cardiovascular risk associated with increased UAE was modified by low compared with high concentrations of serum high density lipoprotein cholesterol (2.86 [1.03-8.48] vs 0.15 [0.01-1.43]). Dysfunction of vascular endothelium may be a link between albuminuria and atherosclerotic cardiovascular disease in NIDDM.

Adult↗

PubMed1992

[Increasing frequency of soft tissue sarcomas in The Netherlands].

Recent data from literature show an increase in incidence and mortality due to soft tissue sarcoma (STS). In the Netherlands age-standardised mortality rates of soft tissue sarcoma (STS) over the period 1950-1988 show a more than fivefold increase. Males predominate over females by a factor of 1.17. Age-adjusted hospital admission rates in 1980-1988 show an increase by a factor of 1.36. The mean estimated incidence is 4.74 per 100,000 person years over a three-year period (1988-1990). The most prevalent histological types in that period were leiomyosarcoma (20.1%), malignant fibrous histiocytoma (16.2%), Kaposi's sarcoma (13.9%) and liposarcoma (13.8%). The distribution of the different histological types changes in time. The increasing incidence of Kaposi's sarcoma is due to the increasing prevalence of AIDS. Hospital admission rates for STS increased from 0.67% of admission rates for all malignant neoplasms in 1970, to 0.96% in 1988. Further epidemiological studies are needed to elucidate the increase of STS throughout the world.

Adolescent↗

PubMed1992

[Neck lymph node dissection in squamous cell carcinoma originating in the head-and-neck area; the significance for the prognosis].

Neck dissection has a therapeutical as well as a prognostic relevance with respect to regional recurrence and distant metastases. Between January 1973 and July 1986 576 neck dissections in 511 patients (396 men, 115 women, among whom 486 with squamous cell carcinoma of the head and neck, and 14 with neck metastases of an unknown primary tumour) were performed at the department of Otolaryngology-Head and Neck Surgery of the Free University Hospital, Amsterdam. Patients with tumour at the margins were excluded. Recurrence-free curves were calculated according to Kaplan-Meier and the log rank test was used to test the differences. All patients underwent a comprehensive neck dissection and were irradiated postoperatively when three or more tumour-positive nodes or extranodal spread were reported by the pathologist. Endpoint for analysis was occurrence of an ipsilateral neck recurrence or of a distant metastasis. Figures were corrected for a simultaneous recurrence at a higher level. A total of 29 neck recurrences (7.2%; n = 523) and 26 distant metastases (10.7%; n = 281) were demonstrated in the 5-year follow-up period. The number of positive nodes was of prognostic significance for both events (p = 0.039 and p = 0.0027). Extranodal spread was shown only to increase the incidence of distant metastases (p = 0.017), whereas its prognostic value with regard to recurrence in the neck was nullified by the strict institution of postoperative radiotherapy. It is recommended to give radiotherapy to patients with two positive nodes and possibly to every patient with a histopathologically positive neck.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

A pilot study on the influence of a corticotropin (4-9) analogue on Vinca alkaloid-induced neuropathy.

In a randomized, double-blind, placebo-controlled pilot study, we examined the effect of Org 2766--a corticotropin (4-9) analogue--on neurotoxicity in 28 patients with lymphoma who were treated with combination chemotherapy containing Vinca alkaloids (vincristine and vinblastine). The patients received a total dose of 12 mg of vincristine in the case of non-Hodgkin's lymphoma and a total dose of 16 mg of vincristine in the case of Hodgkin's disease. Moreover, the patients with Hodgkin's disease received a mean total dose of 84 mg of vinblastine. Subcutaneous injections of 2 mg of Org 2766 or placebo were administered to patients with non-Hodgkin's lymphoma on days 1 and 10 of each chemotherapy course and to patients with Hodgkin's disease on days 1 and 8 of each chemotherapy course. The first injection was always given before the administration of vincristine. Assessment of neurologic symptoms and signs and measurement of sensory thresholds (vibration sense and temperature sense) were performed on day 1 of the first, fourth, and sixth (or eighth) courses and 6 weeks after cessation of chemotherapy. Thirteen patients (mean age, 44.7 years) received Org 2766 and 15 patients (mean age, 54.7 years) received placebo. More symptoms occurred in the placebo group, but only numbness and autonomic complaints occurred significantly more often in the placebo group. Motor deficit and sensory disturbances were more severe and also occurred significantly more often in the placebo group. There was no difference with respect to reflex examination findings and sensory thresholds.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

PubMed1992

1H and 31P magnetic resonance spectroscopy of the brain in degenerative cerebral disorders.

Proton and phosphorus magnetic resonance spectroscopy of the brain was performed in 35 patients with degenerative cerebral disorders: 24 patients had demyelinating (white matter) disorders and 11 patients had neuronal (gray matter) disorders. Four grades of demyelination and three grades of cerebral atrophy were distinguished by magnetic resonance imaging criteria. The spectroscopic data were compared with normal values previously obtained. With increasing degrees of demyelination, lower ratios of phosphodiesters to beta-ATP were found. This trend was statistically significant. Decreased phosphodiester-beta-ATP ratios occurred simultaneously with imaging abnormalities. The decrease in phosphodiester-beta-ATP ratio in demyelinated areas is attributed to white matter rarefaction. Increasing cerebral atrophy was accompanied by lower ratios of N-acetyl aspartate to creatine. This trend was statistically significant. The decrease in the N-acetyl aspartate-creatine ratio was demonstrated before the magnetic resonance images showed signs of cerebral atrophy in patients with neuronal disorders. As N-acetyl aspartate is located exclusively in neurons and their branches, a decrease of the N-acetyl aspartate-creatine ratio can be attributed to neuronal and axonal damage and loss.

Adult↗