Moises Gaviria

Prevalence, Pathogenesis, and Treatment of Renal Dysfunction Associated With Chronic Lithium Therapy

From the analysis of several studies published from 1979 to 1986 comprising 1,172 patients, we estimated that glomerular filtration rate (GFR) was normal in 85% of unselected patients on chronic lithium therapy. The remaining 15% of patients displayed only mild reduction in GFR, clustering at approximately 60 mL/min. Thus, the data available to date do not support earlier concerns that long-term lithium therapy could eventuate into renal insufficiency. The most prevalent renal effect of lithium is impairment of concentrating ability, which we estimated to be present in at least 54% of 1,105 unselected patients on chronic lithium therapy. This defect translated into overt polyuria in only 19% of unselected cases. A renal lesion confined to the collecting tubule has been described in humans who have taken lithium for short periods of time. This lesion may represent the collecting tubules response to the intracellular accumulation of lithium, which interferes with cAMP formation and results in an early and probably reversible inhibition of antidiuretic hormone (ADH)-mediated water transport. However, long-term lithium therapy may induce a progressive and partly irreversible defect in concentrating ability. The potential risk for dehydration associated with lithium-induced polyuria, as well as the discomfort inherent to this side effect, deserves evaluation and consideration for therapeutic intervention. Amiloride has additional advantages over conventional treatment of nephrogenic diabetes insipidus using thiazide diuretics. The action of amiloride on ADH-mediated water transport seems specific in as much as it is capable of preventing the uptake of lithium in high resistance epithelia and thereby prevents the inhibitory effect of intracellular lithium on water transport. Unlike thiazides, amiloride has a weak natriuretic effect and is less likely to increase plasma lithium levels by causing volume contraction. In addition, amiloride, by conserving potassium, obviates the need for potassium supplementation that is usually required to prevent hypokalemia when thiazides are used to treat lithium-induced polyuria. Since amiloride may prevent chronic intracellular lithium accumulation in the collecting tubule, future studies should elucidate whether amiloride also has a role in preventing lithium-induced chronic tubulo-interstitial damage.

Neurocognitive Assessment Before and after Cranioplasty

Summary. Objective: This paper addresses the possible value of neurocognitive tests on the evaluation of patients before and after cranioplasty for large cranial defects. Methods: In a single patient with a large corrected cranial defect a detailed neurocognitive analysis was performed utilizing the EXIT interview and Cognistat before and after surgery. Planning and development of the surgical prosthesis were based on the pre-operative reconstruction of the head CT and on pre-operative pictures of the patient. Xenon-CT anatomical and quantitative cerebral blood flow (CBF) analysis was performed before and periodically after cranioplasty. Findings: A significant improvement in major cognitive functions was observed after surgery. Interpretation: Cognistat is a detailed neuropsychological battery that permits a better assessment of patients in diverse neurological conditions. The EXIT interview gives a better rapid assessment of cognition not provided by other methods, such as the mini-mental status examination (MMSE). The utilization of these techniques permits a better understanding of long-term outcomes for patients with diverse neurological conditions, including post-cranioplasty patients.

Vascular dementia, hypertension, and the brain

Ischemic vascular dementia is a clinical syndrome of acquired intellectual impairment with ischemic cerebral injury resulting from occlusion of cerebral blood vessels and loss of cerebral tissue caused by cerebrovascular disease. With increasing life expectancy, the developed countries have experienced a shift towards a progressively older population. As the average age of the population increases, the prevalence of cerebrovascular disease and vascular dementia is likely to increase. The risk of vascular dementia seems to be correlated with the epidemiologic risk factors of stroke, namely hypertension. Hypertension is thought to be directly associated with vascular dementia and preliminary evidence suggests an association between elevated blood pressure and impairments in cognitive functioning. Recent investigations have found significant associations between hypertension and cerebral dilation and left hemisphere atrophy, and an increased incidence of white matter hyperintensities among hypertensives. Treatment and prevention of vascular dementia and cognitive dysfunction in the elderly require attention to cerebrovascular risk factors, particularly hypertension. Vascular dementias are potentially preventable and cases of Alzheimers disease with vascular components are becoming increasingly recognized.

Relatives of unipolar and bipolar patients have normal pursuit.

Impaired smooth pursuit eye movements are significantly less prevalent among the first-degree relatives of patients who have major affective disorders than among the first-degree relatives of schizophrenics. The distribution of normal and abnormal smooth pursuit among the relatives of unipolar and bipolar patients does not differ from that of normal individuals having no family history of major psychosis. Smooth pursuit impairment is thus specific to relatives of schizophrenic patients and is not characteristic of relatives of patients with major affective disorders.

Reduced platelet MAO activity and vulnerability to psychiatric disorders

Platelet monoamine oxidase (MAO) is a genetically controlled mitochondrial enzyme that metabolizes amines in the brain by deamination. We investigated the relationship between MAO activity and the presence or absence of psychopathology by determining MAO activity and the psychiatric diagnosis in 61 first-degree relatives of 31 patients with bipolar (manic-depressive) illness. Relatives who themselves were diagnosed as having bipolar I illness or alcoholism had a significantly lower mean MAO activity level than did other relatives or 255 normal individuals. These findings indicate that a relationship exists within pedigrees between MAO activity and psychiatric disorders. Reduced MAO activity may play a role in vulnerability to some types of psychopathology.

Diffusion tensor imaging investigations in Alzheimer’s disease: the resurgence of white matter compromise in the cortical dysfunction of the aging brain

Diffusion tensor imaging (DTI) is a sophisticated MRI-based neuroimaging technique that enables in vivo quantification of differences in molecular diffusion at the cellular level. Owing to the highly directional architecture of white matter (WM), DTI is providing important clues of the structure and geometric organization of this neural compartment. Since DTI can detect changes even in the case of radiologically “normal” appearing WM, researchers are using the technique for the study of WM integrity at the initial stages of the most common neurodegenerative disorders. Along with a well characterized cortical pathology (neuritic plaques and intracellular neurofibrillary tangles), WM changes have been also demonstrated in Alzheimer’s disease (AD). However, these changes had been for years found nonliable in the onset and progress of AD, basically due to lack of incriminatory evidence. The use of novel tools such as DTI has enabled the anatomical distribution of WM microstructural damage in the prodromal stages of AD to be gauged and determined, granting a long-delayed protagonic role to WM in the natural history of this highly prevalent neurodegenerative condition.

The process of acculturation: Theoretical perspectives and an empirical investigation in Peru

World-wide migratory patterns have led to an increasing interest in acculturation processes and their psychosocial and psychiatric sequelae. This paper reviews alternative theoretical approaches to the study of acculturation and identifies gaps in the current knowledge base. We then present empirical research on acculturation processes experienced by both Indian rural to urban migrants and White-Mestizo non-migrants in Lima, Peru. The study examined overall acculturation and five sub-dimensions: language use, customs, sociability, perceived discrimination and ethnic identity. The data show that second generation migrants are more highly acculturated across sub-areas and perceive less ethnic discrimination than first generation migrants. The first generation varied in acculturative level across sub-dimensions as a function of their age at the time of migration. Contrasts between the migrant and dominant group depicted a two-way process of culture change, but a process characterized by an inequality in the content exchanged in each direction. Socio-demographic correlates of acculturation were also found. These results are discussed in terms of the potential psychological consequences of alternative acculturative adaptations within the Peruvian social-structural context.

Demoralization and social support in Soviet-Jewish immigrants to the United States

Abstract Two hundred seventy-four recent Soviet-Jewish immigrants to the Chicago area were interviewed and completed psychosocial questionnaires on migration history, social support, and demoralization. Older individuals, women and those with weak social support systems had higher demoralization scores. These data are presented in the context of the history of Soviet-Jewish immigration and recent reports of their adaptation to the United States.

Psychosis in Medical Conditions: Response to Risperidone

We report the response to risperidone in seven hospitalized, adult patients who presented psychotic symptoms etiologically related to a general medical condition. The conditions included brain surgery in two, and anticardiolipin syndrome, renal failure, epilepsy, lupus, and metastatic carcinoma in one each. Four patients had failed previous treatment with at least one typical antipsychotic agent. Response to risperidone was assessed by the Brief Psychiatric Rating Scale (BPRS). Serum was collected for measurement of steady-state trough risperidone and 9-hydroxyrisperidone concentrations at effective doses in three patients. Amelioration of psychotic symptoms was noted in all seven patients. Mean (+/- SD) BPRS scores were reduced significantly from baseline (63.0 +/- 15.1) to endpoint (27.0 +/- 3.5; p < 0.01). The mean effective daily dose of risperidone was 3.1 +/- .7 mg and time to response was 4.7 +/- 2.4 days. Risperidone was not present at detectable concentrations in the three patients studied. The mean steady-state trough serum concentration of 9-hydroxyrisperidone in the three patients assessed was 20.3 +/- 9.8 ng/ml. These preliminary findings, which suggest that risperidone is a safe and effective agent in patients with psychotic symptoms due to various medical conditions, need to be confirmed by randomized, antipsychotic comparison trials involving a larger number of patients.

Xenon/CT quantitative local cerebral blood flow

X enon-enhanced computed tomography (Xe/ CT) cerebral blood flow (CBF) is a method initially developed in the late 1970s which is based on the properties of xenon gas as a contrast agent and on the principle that the rate of uptake and clearance of xenon is proportional to blood flow in brain tissue [ I]. The idea behind the Xc/CT method is rather simple: take several CT scan images of the brain at the same level to assess the build-up of xenon while the patient is breathing it, and translate this into CBF. Unfortunately, the clinical utility of this method was limited by the slowness of CT scan devices, lack of powerful computers, and the need for user-friendly software. All this made the incorporation of Xc/CT in clinical practice quite slow. Nowadays, however, improvements in CT and computer technology have provided the appropriate technical support to perform Xc/CT studies rapidly and easily in day-to-day clinical practice.