Neocortical neurofibrillary tangles correlate with dementia severity in Alzheimer's disease

OBJECTIVE

To determine the relationships between dementia severity and the extent of histopathologic lesions in a variety of brain regions. Neocortical and hippocampal ratings for neurofibrillary tangles (NFTs) and senile plaques (SPs) were compared in 70 cases of clinically and neuropathologically confirmed Alzheimer's disease.

DESIGN

Neuropathologic case series. Dementia severity was assessed by postmortem chart review with use of the extended Clinical Dementia Rating Scale (CDR). Linear association between CDR scores and NFT and SP scores were assessed by partial correlation, controlling for age at death.

SETTING

Studies were conducted at the Alzheimer's Disease Research Center of the Mount Sinai Medical Center, New York, NY.

MAIN OUTCOME MEASURE

Association between CDR scores and neuropathologic changes assessed with the Consortium to Establish a Registry for Alzheimer's Disease semiquantitative scale.

RESULTS

Among these lesion scores, only NFTs showed a significant association with CDR score, and only for neocortical regions. In particular, NFT densities in the superior temporal cortex were most strongly correlated with dementia severity, followed by those in the inferior parietal and midfrontal cortex. No such correlations were apparent for the amygdala, hippocampus, or entorhinal cortex. Medial temporal lobe structures displayed high NFT scores, even in cases of mild dementia. Senile plaques did not correlate significantly with CDR score in any region.

CONCLUSIONS

These data support the notion that neocortical neuronal degeneration, as indicated by NFT formation, is a critical determinant of the clinical progression of Alzheimer's disease and suggest that medial temporal lobe structures may represent the initial site of NFT formation. While SP density correlates with age at death, there is no correlation between SP counts and dementia severity. These results further suggest that the clinical presentation of dementia may be closely related to neurodegeneration in neocortical regions within the temporal lobe.

Impact of cardiopulmonary bypass and cardioplegic arrest on myocardial lymphatic function

Cardioplegic arrest (CPA) is associated with interstitial myocardial edema, which has been shown to impair myocardial function. The accumulation of interstitial myocardial edema may be enhanced by impaired myocardial lymph flow. The purpose of this study was to investigate the effects of CPA on myocardial lymphatic function. In nine anesthetized dogs, we cannulated a prenodal cardiac lymphatic and measured myocardial lymph flow rate (QL), myocardial lymph driving pressure (PL), and myocardial lymph hyaluronan (Hya) concentration. We determined left ventricular function using pressure-volume curves derived by sonomicrometry and micromanometry. The dogs were placed on cardiopulmonary bypass (CPB) (28 degrees C) and subjected to 60 min of hypothermic, crystalloid CPA. With the onset of asystole both QL and PL decreased significantly from 70.7 +/- 31.8 (SD) to 3.3 +/- 4.0 microliters/min and from 19.9 +/- 8.0 to 10.4 +/- 1.8 mmHg, respectively (P < 0.01). Following return of sinus rhythm after separation from CPB, QL and PL increased significantly to 135.4 +/- 28.0 microliters/min and 27.3 +/- 7.5 mmHg, respectively (P < 0.01). Post-CPA myocardial edema was demonstrated by gravimetric wet-to-dry weight determination of 3.67 +/- 0.20 (normal 2.90 +/- 0.20, P < 0.001) and was associated with significantly decreased left ventricular function. Myocardial Hya turnover rate was 1.3 +/- 1.0% per day under baseline conditions and increased significantly to 2.7 +/- 0.9% per day post-CPA (P < 0.01). We conclude that organized myocardial contraction is the major determinant of myocardial lymph flow. Myocardial lymph flow impairment during CPA may contribute to post-CPA myocardial edema and left ventricular dysfunction.

Constitutive secretion of erythropoietin by human renal adenocarcinoma cells in vivo and in vitro

The paraneoplastic syndrome of erythrocytosis is associated with a variety of neoplasms including renal adenocarcinoma, cerebellar hemangioma, and hepatoma. We now report the characterization of the biological and molecular features of an erythropoietin-secreting human renal adenocarcinoma, designated RCCEp+. Serial transplantation of the tumor in athymic mice resulted in a dramatic increase in hematocrit and serum erythropoietin concentration. Growth in vitro was accompanied by a constant rate of erythropoietin secretion. Karyotype analysis demonstrated several unusual features, including the absence of 3p deletions and near tetraploidy. Erythropoietin mRNA was demonstrated by Northern blot both in freshly excised tumor and in tumor cells growing in vitro. Erythropoietin secretion was constitutive and was not induced either by cobalt or hypoxia. Southern blot analysis revealed no rearrangement of the erythropoietin gene in the tumor. Interestingly, in situ hybridization demonstrated erythropoietin mRNA in only a small population of the tumor cells. Further studies of RCCEp+ should prove useful in elucidating the molecular basis for this paraneoplastic syndrome.

Early response to clozapine in schizophrenia

Forty schizophrenic patients were treated with clozapine for 5 weeks. Patients were then classified as treatment responders or nonresponders according to a priori established criteria. After only 1 week of treatment, the responders showed a significant decrease on the Brief Psychiatric Rating Scale (BPRS) total score and the psychosis and tension subscale scores. Higher BPRS scores at baseline and larger improvements in BPRS scores after the first week predicted a more favorable outcome in this trial and yielded good classification accuracy.

Clinical symptoms associated with age at onset in Alzheimer's disease

OBJECTIVE

The aim of the study was to examine the relationship between age at onset of Alzheimer's disease and demographic and clinical characteristics in a large cohort of patients with Alzheimer's disease.

METHOD

The subjects were 104 patients meeting the criteria for Alzheimer's disease of the National Institute of Neurological and Communicative Disorders and Stroke. The relationships of age at disease onset to cognitive and noncognitive variables and to rate of progression were explored by using multiple regression analysis.

RESULTS

Earlier disease onset was associated with the presence of greater language and praxis difficulties and with the development of higher depression scores during the follow-up study period but not with faster disease progression.

CONCLUSIONS

These findings suggest that in Alzheimer's disease, which is a clinically heterogeneous illness, younger age at onset may be related to the presence of more prominent language and praxis impairment and to development of greater depression during the disease course.

Raman spectroscopic measurement of spatial and temporal temperature gradients in operating electrophoresis capillaries

Steady-state and transient intracapillary temperature gradients are measured by Raman microthermometry during capillary zone electrophoresis. The axial temperature gradient away from a heat sink extends for several millimeters, depending upon the contact of the capillary and heat sink. In free-air convection, small radial gradients, 2-4 degrees C from the center of the lumen to the wall, are observed at 0.85 kW/cm3. The temperature profile is adequately described by a parabola. With forced cooling, the center-wall temperature difference is less than 1 degrees C. The time to steady-state temperature after power-on is found to be 20 s. The measurements are compared to the results of heat transport calculations.

Body position does not affect the hemodynamic response to venous air embolism in dogs

Current therapy for massive venous air embolism (VAE) includes the use of the left lateral recumbent (LLR) position. This recommendation is based on animal studies, conducted 50 yr ago, which looked primarily at survival. Little is known, however, about the concomitant hemodynamic response after VAE in various body positions. The purpose of this study was to investigate the hemodynamic and cardiovascular changes in various body positions after VAE. Twenty-two mechanically ventilated supine mongrel dogs received a venous air infusion of 2.5 mL/kg at a rate of 5 mL/s. One minute after the infusion, 100% oxygen ventilation was commenced and the body position of the dogs was changed to either the LLR (n = 6), the LLR with the head 10 degrees down (LLR-10 degrees; n = 6) or the right lateral recumbent (RLR; n = 5) position. Five dogs were maintained in the supine position (SUP; n = 5). One dog died in every group except in the SUP group, where all the dogs recovered. There were no significant differences among the various body positions in terms of heart rate, mean arterial pressure, pulmonary artery pressure, central venous pressure, left ventricular end-diastolic pressure, or cardiac output. The acute hemodynamic changes occurring during the first 5-15 min after VAE recovered to 80% of control within 60 min. Our data suggest that body repositioning does not influence the cardiovascular response to VAE. Specifically, our data do not support the recommendation of repositioning into the LLR position for the treatment of VAE.

A pilot study of clonidine plus physostigmine in Alzheimer's disease

To assess the feasibility of one approach to combined cholinergic/noradrenergic treatment in Alzheimer's disease, ten patients were enrolled in a 2-week placebo-controlled study of oral physostigmine plus clonidine. The Alzheimer's Disease Assessment Scale (ADAS) was used as the primary outcome measure. Neither physostigmine alone, nor the combination of physostigmine plus clonidine, was associated with a statistically significant improvement for the group. Three patients did show an improvement of at least 4 points on the total ADAS score with the drug combination. The implications of these results for treatment strategies are discussed.

Inflammatory mechanisms in Alzheimer's disease: implications for therapy

OBJECTIVE

The purpose of this article is to review evidence that inflammatory and immune mechanisms are important in the pathophysiology of Alzheimer's disease and to suggest new treatment strategies.

METHOD

The authors review the English-language literature of the last 10 years pertaining to the pathophysiology of Alzheimer's disease.

RESULTS

There is ample evidence supporting the hypothesis that inflammatory and immune mechanisms are involved in tissue destruction in Alzheimer's disease. Acute phase proteins are elevated in the serum and are deposited in amyloid plaques, activated microglial cells that stain for inflammatory cytokines accumulate around senile plaques, and complement components including the membrane attack complex are present around dystrophic neurites and neurofibrillary tangles.

CONCLUSIONS

Clinical trials of anti-inflammatory/immunosuppressive drugs are necessary to determine whether alteration of these inflammatory mechanisms can slow the progression of Alzheimer's disease.

Performance of nonpsychotic relatives of schizophrenic patients on cognitive tests

We tested 54 nonpsychotic first degree relatives of 23 schizophrenic probands and 18 control subjects matched for age and education on several neuropsychological tests. The tests were selected to assess overall intellectual ability or because previous work indicated that they are particularly sensitive measures of cognitive dysfunction in schizophrenic patients. The relatives of schizophrenic patients performed significantly worse than the control subjects on tests of verbal fluency and on Trailmaking, part B. Each of these tests contributed unique variance to the discrimination between groups. The groups did not differ significantly on the number of perseverative errors on the Wisconsin Card Sorting Test, Wechsler Adult Intelligence Scale-Revised block design or vocabulary, or Trailmaking, part A. Eight relatives who met DSM-III-R criteria for schizotypal personality disorder were more impaired than the remaining 46 relatives on letter fluency, but otherwise their performance was similar to that of nonschizotypal relatives. These data suggest that close relatives of schizophrenic patients may have subtle neuropsychological impairments that are not necessarily associated with clinical symptoms of schizophrenia spectrum disorders.

Patterns of risk in first-degree relatives of patients with Alzheimer's disease

BACKGROUND

Although an increased cumulative risk for primary progressive dementia (PPD) has been repeatedly demonstrated in relatives of probands with Alzheimer's disease (AD), an examination of their rates of illness at different ages has not been previously undertaken. Such an examination might reveal possible age-related characteristics associated with a more familial variety of AD.

METHODS

Using family history interviews and survival analysis, the cumulative risk for and 5-year age-specific hazard rates of PPD were assessed in the first-degree relatives of 200 probands with AD and two nondemented control groups--179 elderly ascertained through the Alzheimer's Disease Research Center (ADRC-derived controls) and 427 elderly ascertained from community senior centers (community controls).

RESULTS

The PPD risk curve for the relatives of probands with AD rose to about 30% and was significantly higher than the curves for the relatives of the ADRC-derived and community controls, where comparable rates were observed (approximately 12%). The age-specific hazard rates of PPD were calculated in three groups of relatives for each 5-year interval from ages 45 to 49 years through ages 85 to 89 years. The age-specific relative risk (RRi) for PPD in the relatives of probands with AD began to steadily diminish from the 75- to 79-year age interval (RRi = 13.49) through the 85- to 89-year age interval (RRi = 0.96) compared with the relatives of ADRC-derived controls and from the 60- to 64-year age interval (RRi = 16.15) through the 85- to 89-year age interval (RRi = 2.03) compared with the relatives of the community controls.

CONCLUSIONS

These data indicate that, for relatives of probands with AD, while the lifetime risk for PPD is greater than in relatives of controls, the familial contribution to the risk for PPD decreases with increasing age. The higher risk for PPD in relatives of probands with AD may be substantially diminished or even eliminated by the latter half of the ninth decade.

Clozapine treatment and its effect on neuroendocrine responses induced by the serotonin agonist, m-chlorophenylpiperazine

The effects of clozapine treatment on neuroendocrine responses induced by the serotonin agonist, m-chlorophenylpiperazine (mCPP) were examined. mCPP and placebo were administered after a 2-week drug-free period and again after 5 weeks of clozapine treatment in nine schizophrenic inpatients. Adrenocorticotropic hormone (ACTH), prolactin, and mCPP levels were measured. Clozapine treatment completely blocked mCPP-induced ACTH and prolactin release suggesting that clozapine blocks serotonin receptors that mediate these hormone responses.

Cortical cholinergic markers in schizophrenia

Cortical cholinergic deficits have been implicated in the cognitive deficits produced by a variety of neurodegenerative diseases including Alzheimer's disease (AD). Recent studies have suggested that many of the chronically institutionalized geriatric schizophrenic patients are also cognitively impaired. In this postmortem study we compared cholinergic marker activity in six different cortical regions derived from elderly controls, chronically institutionalized geriatric schizophrenic patients, and AD patients. All of the Alzheimer's disease cases met neuropathological criteria for AD, while none of the schizophrenic cases met criteria for AD. Cholinergic marker activity (choline acetyltransferase and acetylcholinesterase) was significantly diminished in the AD cohort but not in the schizophrenic cohort. Additionally, cortical choline acetyltransferase activity was significantly and negatively correlated with Clinical Dementia Rating scores (CDR), whereas no such correlations were evident in the schizophrenic cohort. These results suggest that cognitive deficits in geriatric schizophrenics are not due to diminished cortical cholinergic activity.

A new model for a smoking cessation program: adding compliance efforts and provider education to the mix

MetroHealth, through the coordination of the Pharmacy Department, wanted to establish a smoking cessation program that would provide appropriate and cost-effective therapy. Requirement of patient participation in behavioral modification programs in conjunction with nicotine replacement therapy and continuous provider education allowed the program to attain its goals. The authors describe the nuts and bolts of establishing such a program.

Neocortical cholinergic activities differentiate Lewy body dementia from classical Alzheimer's disease

Activity of the enzyme which synthesizes acetylcholine, choline acetyltransferase, was estimated in the neocortex of three series of control and demented cases. Clinically demented cases were divided into those with the classical neuropathological features of Alzheimer's disease (numerous neocortical plaques and tangles) and those with Lewy bodies in the brain stem and cortex (together with plaques and variable neurofibrillary pathology). In the Lewy body cases neocortical choline acetyltransferase was consistently lower than in the classical Alzheimer-type cases. Two of the Lewy body cases with extremely low cholinergic activity were responders in therapeutic trials of the cholinesterase inhibitor, tacrine, and the combined data suggest that cholinergic therapy may be particularly relevant to patients with Lewy body type dementia.

A longitudinal study of Alzheimer's disease: measurement, rate, and predictors of cognitive deterioration

OBJECTIVE

This study measured the annual rate of cognitive change in patients with Alzheimer's disease and determined the effects of clinical variables on that rate. It also compared the ability of two cognitive scales to measure change over the entire range of dementia severity.

METHOD

The cognitive subscale of the Alzheimer's Disease Assessment Scale and the Blessed test for information memory and concentration were given to 111 patients with Alzheimer's disease and 72 nondemented elderly comparison subjects at 6-month intervals for up to 90 months. Longitudinal changes in scores on the cognitive subscale were measured with several different methods of data analysis.

RESULTS

For the patients with Alzheimer's disease, the annual rate of change in cognitive subscale scores showed a quadratic relationship with dementia severity in which deterioration was slower for mildly and severely demented patients than for patients with moderate dementia. Gender, age at onset, and family history of dementia had no effect on the rate of cognitive deterioration. The comparison group showed a slight improvement in cognitive performance over time. All data analytic methods gave similar results. The cognitive subscale of the Alzheimer's Disease Assessment Scale was more sensitive to change in both mild and severe dementia than was the Blessed test.

CONCLUSIONS

These results suggest that cognitive deterioration is slow during the early and very late stages of Alzheimer's disease and more rapid during the middle stages. No clinical variables other than degree of cognitive impairment and previous rate of cognitive decline predicted rate of deterioration. These results have implications for treatment trials and attempts to identify subgroups.

Neuropsychological correlates of central monoamine function in chronic schizophrenia: relationship between CSF metabolites and cognitive function

Schizophrenia is associated with multiple cognitive deficits which in turn may be related to abnormal dopamine (DA) function. To examine possible associations between cognitive dysfunction and central DA activity in schizophrenia, neuropsychological measures (visuospatial and verbal recall; performance on the Wisconsin Card Sort Test (WCST); visuospatial perception) were examined in 17 drug-free male schizophrenic patients and related to cerebrospinal fluid concentrations of the metabolites of dopamine (homovanillic acid (HVA)), serotonin, and norepinephrine. CSF HVA concentrations were correlated with the ability to recall visuospatial information, with attention to verbal tasks, and with WCST performance (low CSF HVA concentrations predicting poor performance on these tests) but not with the ability to recall verbally presented material and visuospatial perception. These data are consistent with earlier results suggesting that (cortical) DA function is associated with recall and retrieval of visuospatial information and with WCST performance.

Lack of association between cortisol hypersecretion and nonsuppression on the DST in patients with Alzheimer's disease

Among 23 patients with Alzheimer's disease, 11 (48%) exhibited cortisol hypersecretion (> or = 11.8 micrograms/dl) and nine (39%) displayed cortisol nonsuppression on the dexamethasone suppression test. Only four patients exhibited both neuroendocrine abnormalities, demonstrating a lack of association between these two neuroendocrine disturbances of over 50%. Twenty-two of the 23 patients were studied for 4 1/2 years, and 14 died during that period. Six of the eight surviving patients exhibited cortisol hypersecretion without cortisol nonsuppression.

Post-mortem examination of dopaminergic parameters in Alzheimer's disease: relationship to noncognitive symptoms

Dopaminergic mechanisms have been implicated in depression, agitation, and psychosis--symptoms that are frequently observed in patients with Alzheimer's disease (AD). In a longitudinal study, 23 prospectively assessed AD patients underwent autopsies in which concentrations of dopamine, homovanillic acid, and dihydroxyphenylacetic acid were assayed in the temporal lobe (Brodmann areas 20 and 21). Data-reduction techniques were used to minimize the number of relationships tested. For this series of AD patients, no significant correlation was found between indices of dopaminergic neurotransmission and maximal severity of psychosis, depression, or agitation.

A sensitive new bioassay for erythroid colony-stimulating factor

Erythroid colony-stimulating factor (E-CSF) is a B cell-derived membrane protein that specifically affects the growth and development of human and murine committed erythroid progenitors. We report the development of a sensitive new bioassay for E-CSF, based on the ability of the growth factor to stimulate 3H-thymidine incorporation into cloned Rauscher murine erythroleukemia cells. The assay has among its advantages the ability to measure growth factor activity on a purified target cell population in the absence of endogenous growth factor-producing accessory cells. In addition, this assay measures E-CSF's proliferative effect on erythroid progenitors in the absence of erythropoietin (Epo) after 72 to 96 hours. In contrast, the standard bone marrow fibrin clot assay traditionally used to measure E-CSF requires the addition of Epo to promote the development of hemoglobinized erythroid colonies that are quantified after 7 days (for murine cells) to 12 days (for human cells). With the use of this new Rauscher cell bioassay, we have identified an E-CSF-producing human cell line and, further, have measured E-CSF activity derived from nonhuman splenic B lymphocytes.

Alanine scanning mutagenesis of human erythropoietin identifies four amino acids which are critical for biological activity

Erythropoietin regulates the growth and proliferation of red blood cell progenitors. We demonstrated previously the important structural and functional roles of the amino acid region 99-110 in the biological activity of the hormone. [Chern, Y., Chung, T. & Sytkowski, A. J. (1991) Eur. J. Biochem. 202, 225-229]. We have now performed alanine scanning mutagenesis to identify which specific residues in this region are essential for function. Four substitutions reduced the biological activity of erythropoietin. Alanine substitution of Ser104, Leu105 and Leu108 reduced activity to 16, 44, and 37% that of the wild-type protein, respectively. Most significantly, substitution of Arg103 with Ala reduced activity to undetectable levels, indicating a > 230-fold reduction in specific activity. Immunochemical analyses using anti-peptide monoclonal antibodies demonstrated that this substitution does not cause major changes in the conformation of the protein or large, localized distortions within the amino acid region 99-129 of the molecule. Heat-denaturation kinetics for the arginine mutant and wild-type erythropoietin are virtually identical, further indicating the structural similarity between these two molecules. Based upon these findings, we propose that Arg103 plays an essential role in the biological activity of erythropoietin, presumably by interacting directly with the erythropoietin receptor.

Antipeptide antibodies as probes of the recombinant and endogenous murine erythropoietin receptors

The binding of erythropoietin (Epo) to its plasma membrane receptor activates signal pathways that result in erythroid cell proliferation and differentiation. To elucidate the structural features of the receptor that are important for hormone binding and signaling, we have developed a series of site-specific antibody probes. These antibodies were raised against synthetic peptides homologous to six exoplasmic domains and one cytoplasmic domain of the murine receptor and were affinity-purified by binding to their respective peptide antigen, immobilized on agarose. Western blot analyses demonstrated that the recombinant receptor expressed transiently in COS-7 cells is synthesized as three protein species of 62, 64, and 66 kd, consistent with previous observations. Importantly, probing the endogenous receptor in both virally transformed erythroleukemia cells and normal erythroid cells demonstrated similar 62- to 66-kd receptor species. The affinity-purified antibodies also recognized several antigenically related proteins. An examination of the capacity of the antireceptor antibodies to block receptor activation by Epo revealed that antibodies to five of the six exoplasmic domains blocked the receptor. This was reversed with excess Epo. Inhibition of receptor activation by antibody probes to five discrete hydrophilic domains suggests that receptor function may be critically dependent on the structural integrity (conformation) of the entire exoplasmic portion.

Selective loss of dopamine D3-type receptor mRNA expression in parietal and motor cortices of patients with chronic schizophrenia

The expression of dopamine D3-subtype-receptor mRNA was analyzed in defined anatomic regions of brain obtained postmortem from patients with chronic schizophrenia and from controls. The specific amplification of D3-encoding cDNA by PCR allowed the identification of D3 mRNA expression in a wide variety of anatomic regions in both control brains and brains obtained from schizophrenic patients. However, in the parietal cortex (Brodmann areas 1, 2, 3, and 5) and motor cortex (Brodmann area 4), a selective loss of D3 mRNA expression was found in schizophrenia. A different D3 mRNA species was identified that appears to be widely expressed and that is still found in those regions of schizophrenic brains where D3 mRNA could not be detected. Compared with D3 mRNA this RNA is significantly less abundant, and at present its function (if any) is unclear. Many variables associated with either the course and/or the therapeutic management of the disease may account for the selective loss of D3 mRNA in the motor, somatosensory, and somatosensory association areas of schizophrenic brains.

Amyloid precursor protein in the cerebral cortex is rapidly and persistently induced by loss of subcortical innervation

Lesions of the cholinergic nucleus basalis of Meynert elevate the ex vivo synthesis of beta amyloid precursor protein (beta-APP) in the cerebral cortex, a major projection region. We have found that this elevation is reflected by increased levels of beta-APP mRNA. The induction is rapid (occurring 60 min after placement of the lesion) and persistent (remaining for at least 45 days after lesioning). Two other subcortical lesions, which result in reductions of cortical adrenergic and serotonergic innervation, similarly induced cortical beta-APP. The beta-APP induction is reversible and does not require loss of the subcortical neurons. Infusion of lidocaine, a calcium antagonist that disrupts neurotransmitter release, into the nucleus basalis of Meynert leads to the temporary reduction of released acetylcholine in the cortex. In this model, beta-APP mRNA levels are elevated shortly after the infusion of lidocaine (90 min) but return to preinfusion levels 7 days after the lidocaine treatment. However, metabolic stresses of the brain, including chronic physostigmine, glucocorticoid, and diabetogenic treatments, fail to induce the beta-APP response. These results suggest that the induction of beta-APP is a specific response to the loss of functional innervation in the cortex. Importantly, these studies show that cortical beta-APP is induced by lesions that mimic the neurochemical deficits most frequently observed in Alzheimer disease.

Inhibition of the active lymph pump in rat mesenteric lymphatics by hydrogen peroxide

The lymphatic system plays an important role in the regulation of fluid and macromolecular exchange. It is a key "safety factor" against the formation of gross edema. Spontaneous contractions in collecting lymphatics of the rat intestine are necessary for the normal transportation of lymph. Hydrogen peroxide is one of the compounds released in inflammation. Therefore, the effects of H2O2 on the pumping activity of spontaneously contracting lymphatics were evaluated in the anesthetized rat (n = 16). Diameter oscillations of the mesenteric collecting lymphatics were monitored before and after the application of H2O2 (4 and 37 microM). The activity of the lymph pump was evaluated using: contraction frequency (F), stroke volume (SV), ejection fraction (EF), and lymph pump flow (LPF). These parameters were determined from the lymphatic diameter tracings. The following changes in lymphatic activity were seen after a 20 minute exposure to 37 microM H2O2: 1) F declined 85%, from 11.6 +/- 1.5 to 1.9 +/- 1.9 cpm. 2) SV fell over 93%. 3) EF decreased 93%, from 0.57 +/- .07 to 0.05 +/- .04. 4) LPF fell dramatically (> 95%) from 41.5 +/- 10.5 to 2.6 +/- 2.5 nl/min. In conclusion, H2O2 produced an intense inhibition of the active lymph pump and it is possible that the inhibition of the active pump contributes to the edema which occurs during inflammation.

Serotonin function and treatment response to clozapine in schizophrenic patients

OBJECTIVE

Clozapine is the only compound proven to be effective in the 20% of schizophrenic patients refractory to treatment with conventional neuroleptics. Although its mechanism of action has not been elucidated, clozapine appears, in contrast to most conventional neuroleptics, to be a potent serotonin (5-HT) antagonist. This study hypothesized that 5-HT function is increased in patients who benefit from clozapine treatment relative to patients who fail to improve on it.

METHOD

The 5-HT receptor agonist m-chlorophenylpiperazine (MCPP) was used as a probe to examine 5-HT function. MCPP (0.35 mg/kg p.o.) was administered in a placebo-controlled design after a 3-week drug-free period to 19 schizophrenic patients. ACTH, prolactin, body temperature, behavior, and MCPP blood level were measured. Patients were then treated with a conventional neuroleptic, and, having failed to respond to it, were treated with clozapine for 5 weeks (up to 600 mg/day).

RESULTS

Patients who responded to clozapine had significantly higher ACTH responses to MCPP during the drug-free state than the patients who failed to benefit from clozapine. Moreover, the degree of improvement with clozapine, particularly the improvement in psychotic symptoms, was strongly correlated with the magnitude of MCPP-induced ACTH release. Other MCPP-induced responses and MCPP blood level were similar for the two groups and did not correlate with the degree of symptomatic improvement with clozapine.

CONCLUSIONS

Results of this study suggest that MCPP-induced ACTH release, and by inference 5-HT receptor function, may be increased in patients who benefit from treatment with clozapine relative to patients who fail to improve on this drug.

Effect of neuroleptic medication on cerebrospinal fluid monoamine metabolite concentrations in schizophrenia. Serotonin-dopamine interactions as a target for treatment

OBJECTIVE

This study examined the effect of neuroleptic treatment on indexes of dopamine and serotonin function in schizophrenic patients. We hypothesized that neuroleptic treatment would be effective by changing dopamine and serotonin function and/or by altering their interaction.

DESIGN

Lumbar cerebrospinal fluid (CSF) concentrations of the metabolites of dopamine (homovanillic acid, [HVA]) and serotonin (5-hydroxyindoleacetic acid, [5-HIAA]) were measured after a minimum drug-free period of two weeks and again after five weeks of treatment with haloperidol, 20 mg/d orally. Psychiatric symptoms were rated within one day of CSF sampling.

PATIENTS

Sixteen schizophrenic and three schizoaffective male inpatients.

RESULTS

Neuroleptic treatment significantly raised HVA concentrations and significantly increased the ratio between HVA and 5-HIAA. The increase in HVA was not related to symptomatic improvement, whereas the increase in the HVA/5-HIAA ratio was significantly correlated with reduction in overall symptomatology.

CONCLUSIONS

These findings suggest that the increase in HVA is relative to 5-HIAA, and not the absolute increase in HVA, that is related to symptomatic improvement. This, in turn, suggests that changing dopamine function relative to serotonin function, rather than changing dopamine per se, is associated with the therapeutic effect of haloperidol. Exploring serotonin-dopamine interactions in schizophrenia may be more informative than examining each system in isolation.

Functional decline in Alzheimer's disease: a longitudinal study

OBJECTIVE

To assess the reliability of activities of daily living (ADL) measures and determine the rate and pattern of longitudinal ADL change in patients with Alzheimer's disease (AD).

DESIGN

Longitudinal study with evaluations every 6 months.

SETTING

Alzheimer's Disease Research Center Clinics at Mount Sinai Medical Center, New York, and the Veterans Affairs Medical Center, Bronx, New York.

PATIENTS

104 patients meeting NINCDS-ADRDA criteria for probable AD were followed an average of 31 months.

MEASUREMENTS

Physical Self-Maintenance Scale (PSMS) and Instrumental Activities of Daily Living Scale (IADLS) of Lawton and Brody and the Blessed Test of Information, Memory, and Concentration.

RESULTS

For men there was inconsistency over time in the decision about whether or not some IADLS items such as "Laundry" were appropriate for a given patient. Test-retest and inter-rater reliabilities were high for all PSMS items and for IADLS items that were judged to be appropriate. IADLS scores changed an average of 2.06 (+/- 3.27) points annually, and change scores were smaller for patients with severe dementia. PSMS scores changed an average of 2.44 (+/- 3.87) points annually with virtually all change occurring in severely demented patients. There was a marked ceiling effect for the IADLS and a curvilinear relationship of PSMS annual change with PSMS baseline.

CONCLUSIONS

Both PSMS and IADLS measures can be reliable in AD patients, but better IADLS items for males need to be developed. IADLS scores are sensitive to change in mild and moderately demented AD patients, while PSMS scores are sensitive to change in more severely demented patients.

Widespread deficits in somatostatin but not neuropeptide Y concentrations in Alzheimer's disease cerebral cortex

Somatostatin-like immunoreactivity (SLI) and neuropeptide Y-like immunoreactivity (NPYLI) were measured in the cerebral cortex of 49 patients with Alzheimer's disease (AD), and 9 elderly controls. Concentrations of SLI were lower in AD patients relative to controls in 9 of 10 cortical regions. In contrast, no significant differences in NPYLI concentrations between the two groups were observed in any of 10 regions. These studies suggest a dissociation between SLI deficits and NPYLI concentrations in the postmortem cerebral cortex of AD patients. The apparent sparing of NPYLI-containing neurons suggests that neuropeptide Y may be located within a separate group of neurons compared to somatostatin.

Distribution, propagation, and coordination of contractile activity in lymphatics

The propagation and coordination of lymphatic contractions were studied in the mesentery of the rat small intestine using in situ microscopic observation. Indexes of lymphatic diameter were simultaneously measured at two adjacent lymphangions in spontaneously contracting lymphatics (n = 51). Diameter index, contraction frequency, and the percentage of the intersegmental contractions that were propagated and coordinated (PP) were determined at both sites. The conduction velocity of the contractile activity and the percentage of the coordinated contractions that were propagated both antegrade to the direction of lymph flow and retrograde to the flow stream were determined. The results indicate that 1) 80-90% of the lymphatic contractions in the vessels we evaluated were propagated, 2) the wave of contractile activity propagated both centrally and peripherally, and 3) the conduction velocity of the contractile activity was approximately 4-8 mm/s. We tested the hypothesis that gap junctional communication is responsible for the coordination of the contractile event. To accomplish this, we used the gap junction blockers n-heptanol and oleic acid. PP was 90 +/- 4% under normal conditions and fell to a minimum value of 55 +/- 7% during the gap junction blockade. These results indicate that gap junctional communication played an important role in the propagation and coordination of contractions that occurred in spontaneously active lymphatics.

Small cylindrical ultrasound sources for induction of hyperthermia via body cavities or interstitial implants

In this study, small (outside diameter 1 mm) cylindrical ultrasound sources were investigated for induction of hyperthermia in tumours. These ultrasound transducers could be placed in small-diameter body cavities, or they could be used interstitially in brachytherapy catheters. The ultrasound field measurements showed that the field is fairly uniform as a function of the length of the applicator except at the ends where sharp peaks were located. However, there were significant field variations as a function of rotation angle around the transducers. The degree of these non-uniformities varied from transducer to transducer, and also as a function of frequency. The temperature measurements in vitro perfused kidneys showed that therapeutic temperature elevations could be induced in perfused tissues. The radial extent of the therapeutic zone could be increased by circulating water around the applicators, thus avoiding high temperatures on the applicator surface. It was also shown that some control over the temperature distribution along the length of the applicator could be achieved by using a two-element applicator. An array of four applicators implanted in a square pattern with the spacing of 25 mm between the catheters, was able to heat the tissue volume inside of the implant. The results showed that these small ultrasound applicators may offer significant improvement over existing techniques by increasing the penetration depth and the control over the power deposition pattern.

Schizophrenia-related and affective personality disorder traits in relatives of probands with schizophrenia and personality disorders

OBJECTIVE

The possible heterogeneity of the schizophrenia-related personality disorder traits associated with DSM-III criteria for schizotypal personality disorder was investigated using the family history method. A familial relationship to schizophrenia was hypothesized for schizophrenia-related personality disorder traits without coexisting affective personality disorder traits, pure schizophrenia-related personality disorder traits. Alternatively, a familial relationship with borderline personality disorder was hypothesized for schizophrenia-related personality disorder traits with comorbid affective personality disorder traits.

METHOD

Criteria for schizophrenia-related and affective personality disorder traits were used to assess the 588 nonpsychotic first-degree relatives of 55 chronic schizophrenic probands and 67 probands with personality disorders. The probands with one or more DSM-III personality disorders were categorized as having schizotypal personality disorder without borderline personality disorder (pure schizotypal personality disorder), borderline personality disorder without schizotypal personality disorder (pure borderline personality disorder), both disorders, or neither.

RESULTS

The morbid risk of all cases of schizophrenia-related personality disorder traits was higher in relatives of probands with schizophrenia and pure schizotypal personality disorder than in relatives of probands with neither schizotypal nor borderline personality disorder; however, it differed only slightly from that observed in the relatives of probands with both schizotypal and borderline personality disorders and pure borderline personality disorder. In contrast, the risk of pure schizophrenia-related personality disorder traits was higher in relatives of probands with schizophrenia and pure schizotypal personality disorder, while the risk of coexisting schizophrenia-related and affective personality disorder traits was lower in both of these groups than among the relatives of probands with both schizotypal and borderline personality disorders and pure borderline personality disorder.

CONCLUSIONS

These results offer preliminary indications that schizotypal personality disorder features present without comorbid affective personality disorder traits may more specifically characterize the personality characteristics familially related to schizophrenia. Furthermore, they indicate that schizotypal personality disorder features as currently defined are found in relatives of patients other than those with schizophrenia or schizotypal personality disorder.

Severe cognitive impairment in elderly schizophrenic patients: a clinicopathological study

The severe cognitive impairment that affects many of the elderly schizophrenic patients could represent the outcome of schizophrenia in old age for the very severe and chronically ill patients or may be the result of lengthy institutionalization and somatic treatment. Alternatively, it could be due to the presence of concurrent dementing disorders, such as Alzheimer's disease (AD) or multi-infarct dementia. Using an identical neuropathological protocol, brain specimens from schizophrenic patients who showed evidence of severe cognitive impairment were compared with 12 age-matched control cases and the same number of age-matched cases of neuropathologically confirmed patients with AD. Despite their relatively advanced age (mean age 77.1 years +/- 2.8), none of the schizophrenia cases showed sufficient degree of senile plaques and neurofibrillary tangle formations to confirm a diagnosis of AD. Other neurodegenerative disorders associated with dementia were also not identified. These studies suggest that alternative explanations need to be sought for the severe cognitive impairment commonly encountered in elderly schizophrenic patients.

Treatment with clozapine and its effect on plasma homovanillic acid and norepinephrine concentrations in schizophrenia

Measurement of plasma concentrations of the dopamine metabolite, homovanillic acid (pHVA), is an indirect tool to assess changes in dopamine turnover. Levels of pHVA have been reported to decrease during treatment with conventional antidopaminergic, neuroleptics, with the decrement correlating with symptomatic improvement in schizophrenic symptoms. Clozapine, an atypical neuroleptic, is the only drug proved to be effective in treatment-refractory patients. However, the mechanism mediating this unique efficacy has not been fully elucidated. This study examined the effect of clozapine on pHVA concentrations in schizophrenic patients. Since clozapine potently binds to alpha 2-adrenergic receptors, plasma norepinephrine (pNE) concentrations were also measured. Twenty-eight treatment-refractory schizophrenic patients (24 men, 4 women) were treated with clozapine (up to 600 mg/day) for 5 weeks, after a minimum 1-week drug-free period. Symptomatology and pHVA and pNE concentrations were measured at the last drug-free day and weekly for 5 weeks. Fourteen patients responded to clozapine treatment, while an equal number did not. Mean pHVA concentrations did not significantly change during treatment with clozapine. Although clozapine tended to lower pHVA concentrations in treatment responders, the effect was small and not significant. Clozapine treatment significantly raised pNE concentrations, but this did not differentiate responders from nonresponders to clozapine. These findings suggest that clozapine's effect on DA turnover is small and that clozapine may be effective in treatment-refractory schizophrenia by mechanisms other than, or in addition to, dopamine receptor blockade. However, since about one-third of NE is metabolized into HVA, the clozapine-induced increase in pNE may have overshadowed a possible lowering effect of clozapine on pHVA.

Spatially resolved temperature measurements in electrophoresis capillaries by Raman thermometry

Local temperatures inside a 75-microns-i.d. capillary under electrophoresis conditions are measured noninvasively with a Raman microprobe. The method is based on the temperature dependence of the water O-H stretch equilibrium between weakly bent and strongly bent hydrogen bonded species. With calibration against a known temperature standard, this technique is shown to be capable of obtaining spatially resolved intracapillary temperature measurements with an accuracy of +/- 1.0 degree C and a precision of +/- 0.1 degree C. Intracapillary temperatures ranging from 25 to 70 degrees C are observed over the range of buffer compositions and electric fields used. Differences between local temperatures and average capillary temperatures are observed at all operating conditions. The difficulty of an accurate theoretical description of heat dissipation under CE conditions is discussed.

A pilot study of oral physostigmine plus yohimbine in patients with Alzheimer disease

Effective symptomatic treatment of Alzheimer's disease (AD) may require a combination of agents that augment cholinergic as well as noradrenergic neurotransmission. We conducted a pilot study of physostigmine plus oral yohimbine challenge in AD. Ten patients were enrolled in a 12-day double-blind protocol. Each patient received placebo q2h while awake for 5 days, followed by physostigmine 2 mg q2h while awake for 7 days. During each of these drug conditions, yohimbine challenges were administered at oral doses of 10 and 20 mg in a placebo-controlled manner. There was no significant improvement in Alzheimer's Disease Assessment Scale test performance for six patients for whom complete cognitive data were obtained for the 6 challenge days. Nine patients tolerated the protocol with no clinically significant changes in blood pressure, pulse, or electrocardiogram (ECG), and no cardiovascular, gastrointestinal, or autonomic toxicity. One patient complained of chest discomfort associated with tachycardia, a modest rise in blood pressure, and had t-wave inversion in a single precordial lead. These signs and symptoms resolved within a few hours. Serial ECG tracings and cardiac enzymes revealed no evidence of myocardial injury. This pilot study did not reveal major cognitive improvement with this regimen, but underscores the importance of careful cardiovascular monitoring during future combined cholinergic-noradrenergic therapies in AD.

Continuing education in psychotherapy as a method to attract and involve voluntary faculty in an academic department of psychiatry

This article describes the development and nature of an extensive program in continuing education in psychotherapy for voluntary faculty, which operates within a division of psychotherapy. A major goal of the program is to increase the number and quality of psychotherapy supervisors available to train residents.

Empirical assessment of the factorial structure of clinical symptoms in schizophrenia: negative symptoms

The factor structure of the Scale for the Assessment of Negative Symptoms (SANS) was examined in a confirmatory factor analysis that used the LISREL procedure. Four models of negative symptom factors were tested in 130 hospitalized schizophrenic patients. A three-factor model of diminished expression, social dysfunction, and disorganization generated by the authors yielded a superior fit to the data relative to the two-factor model of Liddle (1987b) and a unifactorial severity model. A four-factor model based on the original subscale formulation of the SANS failed to fit the data.

A double-blind, placebo-controlled multicenter study of tacrine for Alzheimer's disease. The Tacrine Collaborative Study Group

BACKGROUND

In Alzheimer's disease, there is a marked decline in the function of cholinergic neurons in the brain. However, studies of treatment with cholinesterase inhibitors have produced conflicting results. We conducted a multicenter trial to evaluate whether the cholinesterase inhibitor tacrine (1,2,3,4-tetrahydro-9-acridinamine monohydrochloride monohydrate) could improve cognition in patients with Alzheimer's disease.

METHODS

Of 632 eligible patients with probable Alzheimer's disease, 215 improved while receiving tacrine during a preliminary crossover phase to determine responsiveness and the best dose. The 215 patients were randomly assigned to receive either placebo or their best dose of tacrine (10 or 20 mg four times a day) in a six-week, double-blind trial. The primary measures of efficacy were the cognitive subscale of the Alzheimer's Disease Assessment Scale and the Clinical Global Impression of Change scale; the secondary measures included the Mini-Mental State Examination and the assessment of the activities of daily living.

RESULTS

At the end of the six-week trial, the patients receiving tacrine had a mean adjusted cognitive-subscale score of 30.3 (Alzheimer's Disease Assessment Scale) as compared with 32.7 in patients receiving placebo. This represents a smaller decline (by 2.4 points) in cognitive performance in the tacrine group (P < 0.001). There were no differences between the groups in their global-rating scores. The tacrine group had a significantly smaller decline in the activities of daily living. The results of the Mini-Mental State Examination favored tacrine, but the differences were small and not statistically significant (a score of 16.0 with tacrine vs. 15.3 with placebo; P = 0.08). Gastrointestinal symptoms, elevation of aminotransferase levels, and headache were the most frequent side effects; all could be reversed by reducing the dose or discontinuing treatment.

CONCLUSIONS

In this short-term study in patients with Alzheimer's disease who were selected for apparent responsiveness to tacrine, treatment with tacrine resulted in a statistically significant reduction in the decline of cognitive function, although this reduction was not large enough to be detected by the study physicians' global assessments of the patients.

Acrylamide polymerization kinetics in gel electrophoresis capillaries. A Raman microprobe study

The formation of 3.5% T, 3.3% C cross-linked polyacrylamide is monitored in 75-microns-i.d. electrophoresis capillaries by Raman microprobe spectroscopy. The disappearance of the acrylamide 1292-cm-1 band is followed with 60-s time resolution for 30 min, and 2-4 min resolution for up to 10 h. Polymerization is 98% complete in 1.5 h and greater than 99% complete after 2 h. In the 900-1700-cm-1 region no bands attributable to cross-linking are observable. Reaction in the capillary follows second-order kinetics. The reaction is faster in the bulk system because heat dissipation is not sufficient to maintain a constant temperature.

Deterioration on the Blessed test in Alzheimer's disease: longitudinal data and their implications for clinical trials and identification of subtypes

One hundred eleven patients with probable Alzheimer's disease (AD) were given the Blessed test (BT) of information, memory, and concentration (scored 0-33) at 6-month intervals over periods of 6-96 months. For each patient, the change in the total BT score between pairs of visits at 6- and 12-month intervals was measured. Mean deterioration scores over 6 and 12 months were 2.2 (SD = 3.2) and 4.1 (SD = 4.1) points, respectively. There was no significant correlation between degree of dementia on the BT and the rate of deterioration. Gender, age of onset, and family history had no significant effect on the rate of deterioration. The implications of the results for treatment trials and investigations of clinical heterogeneity are discussed.

Agitation and postdexamethasone cortisol levels in Alzheimer's disease

The clinical correlates of hypothalamic-pituitary-adrenal (HPA) functioning were examined in 29 patients with probable Alzheimer's disease. The 8:00 a.m. postdexamethasone cortisol levels of these patients were highly correlated with higher agitation scores but not with the degree of depressed mood or memory impairment. The possible neural basis for the association between hypercortisolism and behavioral disturbance in Alzheimer's disease warrants further exploration and replication.

Does modulation of glutamatergic function represent a viable therapeutic strategy in Alzheimer's disease?

Although glutamate dysfunction has been implicated in the pathogenesis of Alzheimer's disease (AD), it is unclear which direction a glutamatergic strategy should take in this illness. Increasing glutamate function may enhance excitotoxicity and neuronal death, whereas decreasing activity in this excitatory amino acid pathway may impair memory processes. Pharmacological modulation of the different NMDA and nonNMDA receptor sites, together with the concept of an agonist versus antagonist approach, are discussed in this review. It would appear that a glutamatergic approach may represent a new and exciting option to pursue in the experimental pharmacotherapeutics of AD.

Nocturnal growth hormone secretion in schizophrenic patients and healthy subjects

Plasma growth hormone concentrations were measured at hourly intervals between 10 p.m. and 8 a.m. the next morning in 15 drug-free chronic schizophrenic male inpatients and 14 healthy males. Growth hormone secretion was significantly lower in the patients as compared with the controls. Growth hormone release peaked around 1 a.m. in the controls, but a growth hormone peak was absent in the patient group. Increased dopamine activity, increased serotonin activity, or both could explain the absence of a nocturnal growth hormone surge in the schizophrenic patients.

Induction of corneal epithelial cytochrome P-450 arachidonate metabolism by contact lens wear

Two biologically active cytochrome P-450 arachidonate metabolites previously were characterized: 12(R)-hydroxy-5,8,10,14-eicosatetraenoic acid (12(R)-HETE) and 12(R)-hydroxy-5,8,14-eicosatrienoic acid (12(R)-DH-HETE), which are endogenously formed in the corneal epithelium. The functional activity of these novel metabolites mimics changes observed in hypoxic corneas. Therefore, the effect of hypoxic stress was examined on metabolite formation in rabbits fitted with polymethylmethacrylate contact lenses. Although applied lenses fit tightly to the rabbit cornea, mechanical irritation also may contribute to the ocular response. Contact lens-induced hypoxic stress stimulated endogenous formation of both 12(R)-HETE (a sodium, potassium adenosine triphosphatase inhibitor) and 12(R)-DH-HETE (a vasodilatory, chemotactic, and angiogenic factor) in a time-dependent manner. After 4 hr of contact lens wear, a 21-fold increase in endogenous 12(R)-HETE formation concomitant with an increase in corneal thickness was observed. After prolonged contact lens wear (144 hr), a 23-fold increase in endogenous 12(R)-DH-HETE formation was found, corresponding with the appearance of a marked conjunctival inflammation characterized by corneal neovascularization. The increased formation of these compounds was associated with time-dependent changes in corneal endothelial morphology. The ability of 12(R)-HETE and 12(R)-DH-HETE to mediate the clinical signs of corneal hypoxia suggest these metabolites may be potential mediators of contact lens complications that followed conditions of hypoxic stress and possibly mechanical irritation in this model.

Homovanillic acid measurement in clinical research: a review of methodology

Despite its serious limitations, measuring the concentrations of homovanillic acid (HVA) in body fluids is perhaps the most direct method currently available to assess the changing activity of central dopamine (DA) neurons in living humans. The concentrations of HVA in body fluids are determined not only by the activity of central DA neurons but also by a number of unrelated factors such as the other sources of HVA and the elimination of HVA from the body. This article reviews many factors that help to determine the concentrations of HVA in body fluids and therefore must be considered in studies employing HVA as a possible index of central DA neuronal activity. The need for further methodological work is indicated to improve the use of body fluid HVA measurements in clinical research.