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PubMed1980

Continuous positive-pressure ventilation decreases right and left ventricular end-diastolic volumes in the dog.

We investigated the mechanism(s) responsible for the decreased cardiac output during continuous positive-pressure ventilation (CPPV). Seven dogs were anesthetized with chloralose-urethane, intubated, and ventilated using a volume ventilator. We measured heart rate, stroke volume, and the determinants of stroke volume: left and right ventricular end-diastolic volumes, isovolumic and ejection phase indices of myocardial contractility, and pulmonary and systemic arterial pressures. Myocardial blood flow was estimated using radioactive microspheres. Variables were measured during a control period of intermittent positive-pressure ventilation (IPPV), 8-20 minutes after the initiation of CPPV using 12 cm H2O positive end-expiratory pressure (PEEP), and 8-20 minutes after the removal of PEEP. CPPV decreased cardiac output but did not affect total or regional myocardial blood flow or the ratio of subendocardial to subepicardial blood flow. Isovolumic and ejection phase indices of myocardial cointractility, heart rate, and systemic arterial pressure did not change during CPPV. Right and left ventricular end-diastolic and end-systolic volumes decreased markedly during CPPV. We conclude that CPPV decreases cardiac output in accordance with Starling's law by decreasing preload.

Animals↗

PubMed1998

Compartmentalization of Th1/Th2 cytokine responses to experimental Yersinia pseudotuberculosis infection in cats.

Specific pathogen-free cats were inoculated subcutaneously into the drainage areas of the left auricular and popliteal lymph nodes with living Yersinia pseudotuberculosis. Inflammation was evident at the inoculation sites and the regional lymph nodes were palpably enlarged at 48 h post-infection. Lymph node enlargement was due to marked paracortical lymphoid hyperplasia and variable neutrophil infiltrates. Yersinia was cultured from the regional lymph nodes and/or spleens of three of the six cats, indicating systemic spread of bacteria. Specific T-helper 1 and 2 (Th1, Th2) cell-associated cytokine mRNA levels were compared in regional lymph nodes, peripheral blood mononuclear cells (PBMC) and spleen at 48 h post-inoculation. Relative to unstimulated control tissues, there was a significant increase in TNF-alpha, IFN-gamma, IL-12, and IL-10 mRNAs in spleen with down-regulation of IL-4. Significant up-regulation of TNF-alpha and down-regulation of IL-4 were also observed in PBMC. Paradoxically, 48 h stimulated lymph nodes showed only minimal differences in cytokine mRNA expression when compared to lymph nodes from mock-inoculated control animals or unchallenged contralateral lymph nodes from the same animal. This study demonstrated that cats, like mice, respond to an intracellular pathogen such as Y pseudotuberculosis with a predominantly Th1-type immune response. The cytokine responses in regional lymph nodes and spleen were asynchronous, while cytokine stimulation in cells of the spleen was mirrored by PBMC.

Animals↗

PubMedDate not supplied

Effect of background correction on left ventricular ejection fraction calculation through analysis of a simple cardiac model.

The dependence of the left ventricular ejection fraction calculation on the background correction in gated cardiac blood pool studies is examined by analyzing a simple cardiac model. It is shown that the ejection fraction is relatively insensitive to the background correction when an accurately determined variable region of interest is used, but that with a fixed region of interest the background correction must be accurately estimated. A similar ejection fraction-background correction relationship is obtained in the analysis of clinical cardiac data. Based on the cardiac model, two methods are suggested which, with further investigation and refinement, may lead to a more accurate and consistent technique for determining ejection fraction and background.

Heart↗

PubMed1987

Human cerebral cortical responses to contralateral transcranial stimulation.

We wished to develop a noninvasive electrophysiological measure of functioning of human cerebral cortex. The response chosen was that elicited by a corticocortical afferent input, specifically the transcallosal response (TCR). We used ourselves as subjects. The large shock artifacts associated with passing large currents through the head were reduced by: stimulating percutaneously with a focal anode (5 cm2) situated midway between F4 and C4 (i.e., frontal region, standard 10-20 nomenclature) and a medially located, semicircular grounded cathode (26 cm2) no closer than 3 to 4 cm away; and recording with the focal scalp electrode over homologous left frontal cortex vs. two or more reference electrodes interconnected through variable resistors and at least 6 cm away. Transcranial stimulation with pulses of 80 to 140 mA and lasting 100 microseconds elicited a brief diphasic deflection (latency, 2 to 4 ms), followed by an initially positive, often bifid wave with a latency of 9 to 14 ms, lasting 18 to 44 ms and reaching 5 to 10 microV. The initial diphasic deflection greatly increased when the stimulating anode was moved laterally over temporalis muscle, indicating an electromyographic (EMG) origin. The EMG, but not the positive wave, was elicited when the interpolar distance was reduced to 1 cm, which greatly reduced the fraction of current traversing the cortex (epicranial stimulation); furthermore, occluding the circulation to the scalp for 30 minutes by rubber tubing above the zygomas and brows dulled sensation, reduced the EMG, but did not alter the latency or rising phase of the positive wave. Early somatosensory components, if present, were small compared with the positive wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗

PubMed2004

Chronic stable ischaemia protects against myocyte damage during beating heart coronary surgery.

OBJECTIVES: Many patients with coronary artery disease demonstrate chronic resting ischaemic myocardial dysfunction. We have investigated whether this ischaemia influences the myocardial damage caused by the period of coronary occlusion involved in beating heart surgery. METHODS: Thirty-three patients with chronic stable angina and normal left ventricular ejection fraction were studied. To make our model clinically appropriate, we included patients with a wide range of ischaemic times, ages and in a subset of 10 patients a surgical preconditioning protocol. Myocyte injury was assessed from venous Troponin T release measured on days 1, 2, and 3. We used intraoperative transoesophageal M mode echocardiograms and simultaneous high-fidelity left ventricular pressure to assess whether patients were demonstrating the functional effects of ischaemia (asynchronous regional contraction with reduced mechanical function). RESULTS: Patients demonstrated the functional effects of resting ischaemia and 17 did not. Patients with resting ischaemia had lower preoperative values of regional peak power and work and all three variables increased significantly with surgery. Venous Troponin T levels at 48 and 72 h postoperatively were lower in those with preoperative resting ischaemia (median (interquartile range) 0.13 (0.08-0.20) vs 0.21 (0.13-0.69) for 48 h and 0.10 (0.08-0.19) vs 0.26 (0.12-0.51) for 72 h). Stepwise multiple linear regression of total postoperative troponin release (measured as the area under the curve of troponin release) demonstrated two independent determinants (R squared for model 0.40): longer ischaemic time, and increasing values of cycle efficiency. The surgical ischaemic preconditioning protocol and preoperative collaterals were not independent determinants. CONCLUSIONS: In patients with chronic coronary artery disease, stable preoperative ischaemia may thus represent a naturally occurring form of myocardial protection, whose presence reduces Troponin T release after beating heart surgery. This protection is different in nature from classical ischaemic preconditioning.

Aged↗

PubMed2005

The present role of nuclear cardiology in clinical practice.

Many advances have been made in the field of nuclear cardiology in the past decade for enhancing the diagnostic and prognostic value of stress myocardial perfusion imaging and the assessment of myocardial viability using SPECT technology. Gated SPECT for determining regional and global function have provided incremental diagnostic and prognostic information in the evaluation of patients with suspected or known coronary artery disease. Left ventricular ejection fraction and regional myocardial wall thickening can now be simultaneously evaluated with regional perfusion particularly with the use of the (99m)Tc-labeled perfusion agents such as sestamibi and tetrofosmin. Many studies have shown that the extent and severity of stress-induced perfusion defects have incremental prognostic value over exercise electrocardiographic stress test variables alone. Patients with normal perfusion scans have <1% combined cardiac death and myocardial infarction rates per year and thus have an excellent prognosis. Diabetics are particularly benefited from stress perfusion imaging for detection of coronary artery disease and risk assessment. Diabetics have a worse prognosis than nondiabetics for the same amount of hypoperfusion on stress SPECT studies. Quantitative rest perfusion imaging with (201)Tl or with one of the (99m)Tc-labeled imaging agents, or PET imaging with (18)F-deoxyglucose can accurately distinguish viable from irreversibly injured myocardium providing useful information for identifying which patients with ischemic cardiomyopathy benefit most from coronary revascularization with a subsequent improvement in left ventricular function and enhanced survival. Finally, serial stress perfusion imaging can be employed to monitor the efficacy of medical therapy that improves endothelial function and myocardial blood flow reserve.

Cardiology↗

PubMed1995

The transverse plane evolution of the most common adolescent idiopathic scoliosis deformities. A cross-sectional study of 181 patients.

STUDY DESIGN: The transverse plane evolution of the most common idiopathic deformities was studied using a cross-sectional database of 181 patients whose deformities were visualized by precise three-dimensional techniques. OBJECTIVE: The objective was to test the hypothesis that for all common idiopathic scoliosis deformities evolution occurs as a torsion, the apex vertebra translating away from the upper end vertebra and at the same time angulating in a clockwise arc for right apex deformities and a counterclockwise arc for left apex deformities. SUMMARY OF BACKGROUND DATA: Perdriolle and Vidal proposed this hypothesis in 1987, which explained observations we had made in 1983 and which was partially supported in thoracic curves in our 1992 study. METHODS: Deformities were characterized as single thoracic major, thoracic major and thoracolumbar or lumbar minor, double thoracic and thoracolumbar or lumbar major, and single thoracolumbar or lumbar major curves. The dependent variable studied was the coronal plane regional angular (Cobb) deformity. The independent variables studied were the lateral and anteroposterior translation of the apex vertebra in relation to the upper end vertebra, and the transverse plane translation and angulation of the apex vertebra in relation to the upper end vertebra. For the model or hypothesis to be true, the apex vertebra to upper end vertebra transverse plane translational distance and angular relationship should increase as the Cobb angle increases. RESULTS: In relation to the upper end vertebra, the apex vertebra always translated laterally, almost always was accompanied by transverse plane translation increase, and usually was accompanied by transverse plane angulation increase. Anteroposterior translation was minimal, but for thoracolumbar and lumbar curves it tended to be posterior. CONCLUSION: The theory that these deformities evolve as torsions, with the apex vertebra translating away from the upper end vertebra and at the same time following a clockwise angular pathway to the upper end vertebra of right apex curves and a counterclockwise angular pathway for left apex curves is supported. Compensatory thoracolumbar and lumbar curves evolve in the same manner as major curves.

Adolescent↗

PubMed1987

Effect of pindolol on neurosympathetic responsiveness, blood flow variability, and conduction in acutely ischaemic myocardium: the importance of heart rate.

The effects of a beta-adrenoceptor antagonist with partial agonist activity (pindolol) were assessed in the open-chest anaesthetised dog during 12-minute periods of left anterior descending coronary artery (LAD) occlusion and reperfusion before and after sympathetic stimulation. Regional myocardial catecholamine efflux, blood flow, and epicardial activation abnormalities were assessed in three groups. In a control group (n = 8), two periods of ischaemia resulted in reproducible intraexperimental changes in catecholamine responses, blood flow, conduction abnormalities, and arrhythmias. Intravenous (i.v.) pindolol (0.45 mg/kg before the second occlusion) reduced nerve-stimulated norepinephrine (NE) overflow from nonischaemic (NI) myocardium but did not modify overflow from ischaemic (I) myocardium either during ischaemia or reperfusion. At constant heart rate (atrial pacing, n = 8), pindolol reduced absolute blood flow to I and NI but had no effect on the ratio of endocardial/epicardial blood flow, arrhythmias, or activation abnormalities during occlusion. Following a reduction in heart rate of 32 +/- 6 beats/min (no pacing, n = 8), pindolol resulted in similar reduction in blood flow to I and NI but also increased the ratio of endocardial/epicardial flow and reduced both spontaneous arrhythmias and activation delay during occlusion. The acute effects of pindolol on conduction abnormalities, arrhythmias, and blood flow distribution in I are thus dependent on reduction in heart rate.

Animals↗

PubMed1999

New evidence from Le Moustier 1: computer-assisted reconstruction and morphometry of the skull.

In this study, we present a new computerized reconstruction of the Le Moustier 1 Neanderthal skull and discuss its significance for Neanderthal growth and variability. Because of the precarious state of preservation of the original material, we applied entirely noninvasive methods of fossil reconstruction and morphometry, using a combination of computed tomography, computer graphics, and stereolithography. After electronic restoration, the isolated original pieces were recomposed on the computer screen using external and internal anatomical clues to position the bone fragments and mirror images to complete missing parts. The inferred effects of general compressive deformation that occurred during fossilization were corrected by virtual decompression of the skull. The resulting new reconstruction of the Le Moustier 1 skull shows morphologic features close to the typical Neanderthal adult state. Residual asymmetry of skeletal parts can be traced to in vivo skeletal modification: the left mandibular joint shows signs of a healed condylar fracture, and the anatomy of the occipital region suggests mild plagiocephaly. Using micro-CT analysis, the left incus could be recovered from the matrix filling of the middle ear cavity. Its morphometric dimensions are similar to those of the La Ferrassie III incus. The morphometric characteristics of the inner ear deviate substantially from the condition reported as typical for Neanderthals and fall within the range of modern human variability.

Animals↗

PubMed2001

The effect of medial frontal and posterior parietal demyelinating lesions on stroop interference.

Functional imaging has consistently shown that attention-related areas of medial frontal and posterior parietal cortices are active during the attentional conflict induced by color naming in the presence of distracting words (Stroop task). Such studies, however, have provided few details of the correlational nature between observed regional brain activations and reaction time delay occurring in this situation. We analyzed the effect of medial frontal and posterior parietal lesions on the Stroop response in a group of patients with multiple sclerosis, a neurological disorder in which Stroop response speed is affected to varying degrees. Forty-five patients were assessed using a computer-presented verbal version of the Stroop task and specific MRI protocol. Demyelination areas were measured on five anatomical divisions of the medial frontal white matter and on white matter of the posterior parietal lobe. We found that a combination of frontal and parietal lesion measurements accounted for 45% of the Stroop interference time variance. Patients with more right frontal than left parietal demyelination showed slowed Stroop responses, whereas the predominance of lesions in the left posterior parietal region was associated with a reduced Stroop interference. These results may contribute to defining the specific participation of these attention-related brain areas in the conflict of attention represented by the Stroop paradigm. They also help to explain the variability of the Stroop effect in multiple sclerosis patients and suggest that the Stroop test does not assess just a single cognitive operation, but rather the combined effect of anatomically segregated neural processes.

Adult↗

PubMed2004

Heroin abusers' performance on the Tower of London Test relates to the baseline EEG alpha2 mean frequency shifts.

Planning function deficit is the most consistent finding in neuropsychological studies of heroin addicts. The performance on the Tower of London Test (TLT) correlated with the duration of daily heroin abuse (DDHA) in our previous study. Alpha2 mean frequency in anterior/central derivations was also predicted by DDHA in the same patient population. This retrospective study was undertaken in order to understand better the relationships between observed neurological deviations in heroin abusers. Thirty-three heroin addicts and 12 healthy males were evaluated with 14 neuropsychological tests and resting eyes-closed electroencephalography (EEG). Multivariate tests showed that performance on the difficult (five-move) problems of TLT was strongly predicted by the EEG alpha2 mean frequency shifts, and these relationships were generally mediated by chronic heroin length. However, post-hoc analyses at separate leads demonstrated that the relationships between cognitive variables and alpha2 mean frequencies in the left hemisphere were independent of chronic heroin effects, whereas elevation of alpha2 frequency in the right hemisphere was strongly predicted by chronic heroin intake length. The patients with extremely high alpha2 mean frequency at the left central region were especially prone to failure in TLT due to the inability of the hypothesized alpha2-generating network, which normally projects to the central and temporal derivations bilaterally and to the right posterior temporal derivation to function appropriately. Hence, it was concluded that planning dysfunction in heroin abusers is related to alpha2 mean frequency shifts predominantly at the central regions.

Adult↗

PubMed2003

Activation of cortical areas in music execution and imagining: a high-resolution EEG study.

Neuroimaging studies have shown that execution of a musical sequence on an instrument activates bilateral frontal opercular regions, in addition to bilateral sensorimotor and supplementary motor areas. During imagining activation of the same areas without primary sensorimotor areas was shown. We recorded EEG from 58 scalp positions to investigate the temporal sequence and the time course of activation of these areas while violin players prepared to execute, executed, prepared to imagine, or imagined a musical sequence on a violin. During the preparation for the sequence in three of seven musicians investigated the bilateral frontal opercular regions became active earlier than the motor areas and in one of them simultaneously with the motor areas. In two of the musicians a rather variable pattern of activation was observed. The frontal opercular regions were also strongly involved throughout the period of music execution or imagining. The supplementary motor area was involved in both preparation for the sequence and during execution and imagining of the sequence. The left primary sensorimotor area was involved in the preparation and termination of the musical sequence for both execution and imagining. The right sensorimotor area was strongly involved in the preparation for and during the execution of the sequence. We conclude that the bilateral frontal opercular regions are crucial in both preparation for and during music execution and imagining. They may have "mirror neurone" properties that underlie observation or imagining of one's own performance. The motor areas are differentially activated during the preparation and execution or imagining the sequence.

Adult↗

PubMed1983

Short-term responses to cardiac rehabilitation after acute myocardial infarction. Cardiac function evaluation before and after physical training at rest and during stress test.

Whether physical training, soon after myocardial infarction (MI), has effects upon intrinsic cardiac function at rest and during exertion remains unresolved. We have evaluated ventricular function using radionuclide angiography at rest and during stress testing before and after 3 months' physical training. This has been correlated with the site of MI and with changes in the ST segment during the maximal exercise test performed before the postmyocardial infarction rehabilitation program. We have studied 27 patients, mean age 54 +/- 10 years, in NYHA class I or II. Twelve showed no changes in the ST segment during erogmetric stress test (group 1); seven showed ST segment depression greater than 1 mm in leads different from those of MI (group 2); eight showed ST segment elevation of 2 mm (group 3). Twelve patients had had anterior MI only (AMI group); twelve inferior MI only (IMI group). After rehabilitation, all patients showed an increased work capacity and a decreased double product at the same work load. In the total group, significant increases were found in the left ventricular ejection fraction (LVEF) and in the contractile regional performance (LVwm) at rest, as well as a lesser decrease in the LVEF during handgrip test. Group 1 showed a significant increase in LVEF, associated with a decrease in left ventricular end-diastolic volume (EDV) at rest. Group 2 showed unchanged variables after rehabilitation. Group 3 showed a better LVEF during handgrip with an increase of EDV at rest. The AMI group showed a better LVEF and LVwm at rest and a better LVEF during handgrip. IMI group showed a better right ventricular ejection fraction during handgrip without improvement in LVEF. No patient with IMI had septal asynergy. We conclude that the effects of rehabilitation were linked to the site of MI and to the functional dynamic status of both ventricles.

Electrocardiography↗

PubMed2000

Fine volumetric analysis of the cerebral ventricular system in schizophrenia: further evidence for multifocal mild to moderate enlargement.

We used traditional volumetric regional analysis and a finer anterior-posterior (AP) profile volumetric analysis to examine the cerebral ventricular system in an all-male, demographically matched sample of schizophrenia patients (n = 73) and normal controls (n = 29) using 2.8-mm-thin coronal T1-weighted magnetic resonance images from a 1.5 tesla scanner. Traditional regional analysis was performed on various regions using absolute volumes after adjusting for intracranial volume (ICV) and age. The fine AP profile analysis was done by intrasubject "stacking" of contiguous coronal cross-sectional volumes (adjusted for ICV and age) across the AP plane, intersubject AP alignment of all slices relative to the mammillary bodies, and plotting of slice volumes along the AP plane with 95 percent t-test-based confidence intervals. Schizophrenia subjects had mild to moderate multifocal ventricular enlargement (overall effect size d = 0.48), which was especially prominent in the right posterior temporal horn and, more generally, in the central to posterior portions of the lateral and third ventricles. Schizophrenia subjects also had milder enlargement in the left frontal horn, but no significant differences were found in the anterior temporal horns and the right frontal horn. Post hoc analyses of demographic, clinical, and neuropsychological variables did not account for much variance in the ventriculomegaly observed in the schizophrenia group. The lack of a single locus in the observed ventricular enlargement, the nonsignificant results from schizophrenia subtypes based on regional distributions, and the strong positive correlations among the ventricular regions for the schizophrenia group suggest that the ventriculomegaly seen in this chronic population reflects a single brainwide disease process leading to a multifocal or patchy loss of integrity in brain structure.

Adult↗

PubMed1978

Regional oxygen saturation of small arteries and veins in the canine myocardium.

Oxygen saturation of small arteries and veins (20-500 micron) was determined microspectrophotometrically in the hearts of 12 pentobarbital-anesthetized open-chest dogs. Hearts were removed, quick frozen in liquid propane, and O2 saturation was determined in blood vessels on a regional basis between and within ventricular walls. No significant differences existed in arterial O2 saturation between right, left, and septal walls or regionally within any wall by depth or in base-to-apex comparisons. Although there was variation in arterial saturation, it was independent of vessel size. Arteries were followed by serial section into the left ventricular wall for distances up to 7.5 mm without significant saturation change. The average venous saturations of the right, septal, and left ventricular walls were not significantly different. No regional differences in venous saturation were found within any ventricular wall in comparisons between base and apex. In the left ventricle, subepicardial venous saturation (29.8%) was significantly higher than subendocardial saturation (16.4%). In veins traced from the surface, saturation decreased with depth. Greater variability of saturation was found in small compared to large veins. The greater O2 extraction in the subendocardium may indicate a higher O2 consumption than in the subepicardium.

Animals↗

PubMedDate not supplied

The comparison of the effects of fluticasone propionate and budesonide on clinical indices and on bone mineral density in the asthmatic patients: a one year treatment study.

BACKGROUND: it is well accepted that the inhaled administration of steroids is efficacious and has fewer side effects than the systemic use. Among them fluticasone propionate (FP) has been said to cause the similar antiasthma effect without unfavorable side effect at half the dose of the other ICS. The aim of the study was to compare the effects of FP 500 microg/day and budesonide (BUD) 800 microg/day as a pressurized metered dose inhaler (pMDI) for one year on clinical indices determined by FEV1 and diurnal variation of PEFR (peak expiratory flow rates) and on laboratory indices determined by serum cortisol and bone mineral density (BMD). METHODS: a total of 30 nonsmoking mild to moderate asthmatic patients were recruited the study. 15 patients were given 800 microg/day BUD and 15 patients were given 500 microg/day FP as a pMDI. BMD measurements were done with dual energy X-ray absorbtiometry (DEXA) before and after the treatment at the lumbar area of the spine (L1-4) and left hip (trocanter major, neck of femur, intertrocanteric region and Ward's triangle). 10 patients of BUD group and 13 of FP group completed the study. After a year of treatment period, patients were compared on the basis of clinical indices (FEV1 and variability of PEFR), on serum cortisol levels and on BMD in both groups. RESULTS: after the treatment, variability of PEFR (in BUD group p < 0,01, in FP group p < 0,001) and FEV1 (in BUD group p < 0,05, in FP group p < 0,05) were both improved in the groups. Serum cortisol levels and BMD of the patients in both groups were not changed significantly (p > 0,05). CONCLUSIONS: the results suggested that FP 500 microg/d and BUD 800 microg/d as a pMDI results in a similar antiasthma effect without causing any adverse effect on BMD in mild and moderate asthmatics after one year treatment period.

Administration, Inhalation↗

PubMed1988

A model for regional blood flow measurements during cardiopulmonary resuscitation in a swine model.

Recent reports examining regional blood flow during cardiopulmonary resuscitation (CPR) have been criticized for several reasons: (1) cardiac arrest times of 5 min or less are not reflective of the prehospital setting, (2) anesthetic agents may significantly influence autonomic control of regional blood flow, (3) canine cardiac anatomy and coronary blood supply are not reflective of humans and (4) precise validation data for blood flow measurements have not been reported. This study presents a methodology and model for measuring regional blood flow during CPR after a prolonged cardiac arrest. Fifteen swine weighing 15-25.4 kg were instrumented for regional blood flow measurements using tracer microspheres. Regional cerebral and myocardial blood flow were measured during normal sinus rhythm (NSR) and during CPR following a 10-min cardiopulmonary arrest. Regional blood flow (ml/min/100 g) to the cerebral cortices averaged less than 3% of baseline flow (NSR: right cortex = 41.2 +/- 13.8; left cortex = 41.2 +/- 12.2; CPR: right cortex = 1.3 +/- 1.2; left cortex = 1.3 +/- 1.3). Total myocardial blood flow averaged less than 5% of baseline flow (NSR = 211.5 +/- 104.9; CPR = 9.5 +/- 14.9). The flow data demonstrates minimal cardiac and cerebral perfusion with standard CPR following a 10-min arrest. The variability in the pilot data may be used in determining sample sizes for future studies.

Animals↗

PubMed1992

The volume of the mediodorsal thalamic nucleus in treated and untreated schizophrenics.

Reductions of 40% in total cell number and 25% in volume of the mediodorsal thalamic nucleus were recently reported in an unbiased neurostereological study of neuroleptic-treated schizophrenic patients. In order to investigate whether these results might be secondary to many years of treatment with neuroleptic drugs, eight brains from schizophrenics never treated with neuroleptics and eight controls were studied using the unbiased Cavalieri volume estimator. To compare left-right differences in this region, twelve neuroleptic-treated schizophrenics and eleven control cases were compared. The brains used for the left-right comparison study and five of 20 used for comparison of treated and untreated brain volumes have been used in an earlier study. The mediodorsal thalamus volume was reduced by 31% in untreated schizophrenics and by 22% in neuroleptic-treated schizophrenics. No differences were found in mean total volume of the left and right mediodorsal thalamus in brains from controls nor from schizophrenics. A major difference exists with respect to time of fixation in controls (12 years) and untreated schizophrenics (39 years) that makes shrinkage differences a possible confounding variable. The results suggest that the consistent reduction in number of neurons in the mediodorsal thalamic nucleus are not secondary to prolonged treatment with neuroleptic drugs and that asymmetry in this specific brain region is not a feature of the schizophrenia-afflicted brain.

Adult↗