Immune mechanisms of smooth muscle hyperreactivity in asthma

Asthma is characterized by bronchial hyperresponsiveness to a variety of bronchospasmogenic stimuli. To study the pathophysiologic mechanisms underlying the increased sensitivity and degree of maximal airway narrowing, various in vivo and in vitro models have been developed with methods of active and passive sensitization. These studies indicated a major role for alterations in the smooth muscle itself rather than neural dysfunction or airway inflammation as the underlying cause for the development of bronchial hyperresponsiveness. During the last years smooth muscle cells were found to exhibit not only the "classical" contractile phenotype but also a proliferative-synthetic phenotype, which is capable of producing proinflammatory cytokines, chemotaxins, and growth factors. Allergic sensitization can alter both contractile and secretory functions, thereby indicating that the smooth muscle cell could contribute directly to the persistence of airway inflammation in asthma. A better understanding of the changes within the smooth muscle cells and of the mechanisms that lead to their induction could contribute to the development of novel therapeutic approaches for the treatment of asthma.

The effect of the enantiomers of formoterol on inherent and induced tone in guinea-pig trachea and human bronchus

The long-acting beta2-adrenoceptor agonist formoterol is, like all other members of this class of drugs, used as a racemate in the clinic. While the effects of the individual enantiomers have been studied on airway smooth muscle from guinea pig, comparable data on human bronchial smooth muscle are scanty or absent. Therefore, we compared the effects of the enantiomers of formoterol on inherent and induced tone in isolated human bronchi with that on guinea-pig trachea in vitro. The human bronchi either were studied under resting tension conditions or were precontracted with 10 microM carbachol or 0.1 mM histamine. The guinea-pig trachea was precontracted with 0.01, 0.1 or 1 microM carbachol. The racemate and (R,R)-formoterol caused a concentration-dependent relaxation of all preparations with an EC50 of about 1 nM. In the guinea-pig trachea, the concentration-effect curve for formoterol was moved to the right in response to an increased concentration of carbachol. In both human bronchus and guinea-pig trachea, (S,S)-formoterol was more than 1,000 times less potent than (R,R)-formoterol. Thus the relaxing effect of formoterol in human airways as well as in guinea-pig trachea was shown to lie with the (R,R)-enantiomer. Notably, (S,S)-formoterol did not exert any contractile effects within the tested concentration range in either airway preparation. Therefore, we conclude that with regard to relaxant effects the pure (R,R)-enantiomer of formoterol does not offer a benefit over the racemate.

Factors influencing T-cell turnover in HIV-1-seropositive patients

HIV-1 disease is associated with pathological effects on T-cell production, destruction, and distribution. Using the deuterated (2H) glucose method for endogenous labeling, we have analyzed host factors that influence T-cell turnover in HIV-1-uninfected and -infected humans. In untreated HIV-1 disease, the average half life of circulating T cells was diminished without compensatory increases in cell production. Within 12 weeks of the initiation of highly active antiretroviral therapy (HAART), the absolute production rates of circulating T cells increased, and normal half-lives and production rates were restored by 12-36 months. Interpatient heterogeneity in the absolute degree of turnover correlated with the relative proportion of naive- and memory/effector-phenotype T cells in each of the CD4+ and CD8+ populations. The half-lives of naive-phenotype T cells ranged from 116-365 days (fractional replacement rates of 0.19-0.60% per day), whereas memory/effector-phenotype T cells persisted with half-lives from 22-79 days (fractional replacement rates of 0.87-3.14% per day). Naive-phenotype T cells were more abundant, and the half-life of total T cells was prolonged in individuals with abundant thymic tissue, as assessed by computed tomography. Such interpatient variation in T-cell kinetics may be reflective of differences in functional immune reconstitution after treatment for HIV-1 disease.

p53 immunoreactivity in biopsy specimens of T1G3 transitional cell carcinoma of the bladder--a helpful parameter in guiding the decision for or against cystectomy?

The aim of this study was to determine whether p53 is helpful in making the decision to undergo cystectomy in T1, G3 transitional cell carcinoma (TCC) of the bladder, by prospectively comparing the p53 status of bladder biopsies with the histology and p53 status of the corresponding cystectomy specimens. From January 1996 to August 1997, 38 consecutive patients with T1G3 TCC at 6 different centres were enrolled into the study. Bladder biopsies and cystectomy specimens were examined with three different antibodies against p53. The p53 status of each bladder biopsy was compared with p53 status, tumour stage and grade of the cystectomy specimen. An independent evaluation of the histology and immunohistochemistry was carried out by two pathologists. 15 of 38 patients (39%) were found to have a higher tumour stage in the cystectomy specimen compared with the staging by transurethral resection of the bladder tumour (TUR-B). 3 patients did not show residual tumour in the cystectomy specimen. No differences in p53 positivity were noted between the different antibodies. 14 of 31 evaluable tumours (45%) were p53 positive at the time of the TUR-B. p53 staining of the TUR-B specimen did not correctly predict the residual tumour in the cystectomy specimen. We, therefore, concluded that compared with standard histopathology, the p53 status of the TUR-B specimen does not provide additional relevant information with regard to local tumour staging and, thus, is not helpful in making the decision for or against a cystectomy.

Long-term results of laser treatment for retinal angiomatosis in von Hippel-Lindau disease

PURPOSE

In von Hippel-Lindau disease (VHL), retinal detachment is often a real threat if the retinal angiomas are left untreated. The aim of this trial was to diagnose and treat capillary angiomas early at an asymptomatic stage.

METHODS

Since 1983, we have investigated patients with key lesions and those who are at risk for VHL in a multidisciplinary study. Classical retinal angiomas and microangiomas were treated with the Argon laser. Checks during a follow-up of 15 years have provided us with long-term results.

RESULTS

We detected 189 retinal angiomas in 97 eyes of 69 patients (105 classical angiomas, including 19 fibrotic angiomas in 15 eyes, 84 microangiomas). During the study, 20 patients (twenty-one symptomatic eyes) entered the study already with a visual impairment. Sixty asymptomatic eyes from 49 patients with a total of 108 retinal angiomas (55 microangiomas and 53 classical angiomas) were treated by us with photocoagulation. Nineteen asymptomatic eyes with angiomas of fibrotic type were observed only. During a mean follow-up of 5.1 years (range: 0.25 - 15; SD: 3.88) observed after treatment, no deterioration of vision occurred in 37 patients treated with photocoagulation. Regular controls showed 5 relapsing angiomas and 9 new angiomas which were successfully coagulated again. New angiomas occurred in those eyes with several angiomas as a predisposition. Patients with a tendency to multiple angiomas need to be seen more frequently because these eyes have a high risk of becoming blind, even in already coagulated angiomas.

CONCLUSION

Laser treatment was successful. Early ophthalmological examination of patients with retinal angiomatosis is a great challenge, since these lesions can only be successfully treated at an early stage. Treatment is then effective and safe, but long-term follow-up is necessary. New angiomas occurred in those eyes with several angiomas as a predisposition.

The difference between electroacupuncture only and electroacupuncture with manipulation on analgesia in rats

Plain acupuncture uses manipulation (rotation or varying the depth of insertion of the needle) to increase its effect. However, in commonly used electroacupunture (EA), variable manipulations have not been used. This study was performed to investigate the possibility of an increase in analgesic effect by adding manipulation to EA. The pain index used was the Tail-Flick latency (TFL) of the rat, which was lightly anesthetized with thiopental sodium (intraperitoneally). Four types of manipulation were used. Rotation and varying the depth of the needle (RN and VN) was employed using two different types of manipulation during each 20 min stimulation of EA. Each manipulation persisted for 1 min out of every 5 min (long - duration and long - interval: LDLI) or 12 s every 1 min (short - duration and short interval: SDSI). EA produced an increase in TFL; peak value was 49.7+/-12.2% of the pre - EA and occurred immediately after cessation of 20 min of EA stimulation. Performing RN or VN combined with EA also increased TFL more than just EA and a greater peak increase in TFL was observed with a SDSI - RN and SDSI - VN as compared to a LDLI - RN and LDLI - VN (77.5+/-13.8, 79.2+/-19.8 and 67.3+/-14.0%, 65.6+/-23.7% of the pre - EA, respectively). These results indicate that manipulation combined with EA produces a more potent antinociception than when only EA is applied.

Serum immunoglobulin E levels predict human airway reactivity in vitro

BACKGROUND

Airway hyperresponsiveness to non-specific stimuli is one characteristic feature of airway diseases such as bronchial asthma and chronic bronchitis. Until now, studies aiming to demonstrate a relationship between in vivo conditions associated with airway hyperreactivity and in vitro airway responsiveness have been inconclusive.

OBJECTIVE

Since serum immunoglobulin (Ig) E is believed to be one determinant of airway reactivity in vivo, we studied whether in vitro airway reactivity in lung resection material from patients with elevated levels of serum IgE was increased as compared with patients with undetectable IgE. By this approach, we aimed to elucidate the role of circulating IgE for bronchial smooth muscle reactivity in vitro.

METHODS

Bronchial rings from nine patients with total serum IgE levels above 200 U/mL and 10 patients with total serum IgE levels below 10 U/mL were passively sensitized, i.e. incubated overnight with buffer or sensitizing serum containing high levels of total IgE (> 250 U/mL). Afterwards, contractile responses to histamine were assessed in the organ bath.

RESULTS

Histamine responsiveness was significantly increased in airways obtained from patients with IgE levels above 200 U/mL as compared with airways from patients with IgE levels below 10 U/mL (P < 0.05). Passive sensitization of bronchi from patients with low IgE significantly increased histamine responsiveness, as compared with non-sensitized controls from the same patients (P < 0.05). In contrast, passive sensitization of airways from patients with elevated IgE did not further increase responsiveness. There was no difference in histamine reactivity between non-passively sensitized and passively sensitized tissue preparations from patients with IgE above 200 U/mL and passively sensitized tissues from patients with IgE below 10 U/mL.

CONCLUSION

Our findings reveal that elevated levels of serum IgE predict airway hyperresponsiveness to histamine in vitro. At the same time, they indicate that the in vitro model of passive sensitization, in addition to its ability to induce allergen responses, also mimics conditions of non-specific airway hyperreactivity, which are relevant under in vivo conditions.

The role of leukotrienes in the regulation of tone and responsiveness in isolated human airways

Cysteinyl-leukotrienes and histamine are the major determinants of inherent tone in isolated human bronchi, which is mainly the result of a balance of continual production and release of contractile mediator, in particular cysteinyl-leukotrienes and to a lesser extent histamine, and on the other side bronchodilating prostanoids. Cysteinyl-leukotrienes are also powerful constrictors of isolated human airways through direct interaction with Cys-LT1 receptors on airway smooth muscle, and with a potency 1,000-fold higher than histamine. On stimulation inflammatory cells such as eosinophils and mst cells produce and release significantly increased amounts of leukotrienes leading to smooth muscle contration in vitro. In isolated human airways, leukotrienes are the most important mediators of allergen and adenosine-induced contractile responses. The induction of allergen responses in passively sensitized airways is not only related to an increased release of leukotrienes and histamines, but also to an enhanced responsiveness of the airway smooth muscle, particularly to LTC4. Studies in isolated human airways in vitro have demonstrated that understanding the regulation of human airway tone and airway reactivity are closely linked to the understanding of baseline and stimulated production of and smooth muscle responsiveness to leukotrienes in vitro and in vivo.

Quantification of fungal DNA by using fluorescence resonance energy transfer and the light cycler system

The Light Cycler technique combines rapid in vitro amplification of DNA in glass capillaries with real-time species determination and quantification of DNA load. We have established a quantitative PCR protocol for two clinically important pathogens, Candida albicans and Aspergillus fumigatus. The sensitivity of the assay was comparable to those of previously described PCR protocols (5 CFU/ml). Specific detection of C. albicans and A. fumigatus could be achieved. The assay showed a high reproducibility of 96 to 99%. The assay was linear in a range between 10(1) and 10(4) Aspergillus conidia. As capillaries do not have to be reopened for post-PCR analysis, the risk of carryover contaminations could be minimized. The Light Cycler allowed quantification of the fungal loads in a limited number of clinical specimens from patients with hematological malignancies and histologically proven invasive fungal infections. Five of nine positive samples had fungal loads between 5 and 10 CFU/ml of blood, two of nine positive samples had fungal loads between 10 and 100 CFU/ml of blood, and two of nine samples had fungal loads of more than 100 CFU/ml of blood. All samples were also found to be PCR positive by PCR-enzyme-linked immunosorbent assay analysis.

Prolonged exposure to intermittent alcohol vapors blunts hypothalamic responsiveness to immune and non-immune signals

BACKGROUND

We have previously shown that long-term alcohol treatment blunts the ACTH response to alcohol itself, as well as to other stresses, and is accompanied by decreased pituitary responsiveness to vasopressin (VP), but not corticotropin-releasing factor (CRF). The present work aims to determine the relevance of changes in CRF and VP receptors in the pituitary gland and/or peptide stores of CRF neurons in the paraventricular nucleus (PVN) of the hypothalamus, the areas that are most directly involved in ACTH release.

METHODS

Intact male rats were exposed to alcohol using a new vapor delivery system which enables individual rat housing in boxes. Alcohol treatment was delivered for 6 hr once daily (0700-1300), after which the rats were returned to their home cages where they had free access to food and water. Control rats were kept in similar boxes, but not exposed to alcohol. Total treatment time was 8 days. All animals were equipped with indwelling jugular cannulae that were used to monitor blood alcohol levels (BALs) as well as ACTH and corticosterone release throughout drug exposure. Due to the presence of a swivel, the animals' movements were not restricted or hindered by the presence of these cannulae. On the morning of day 9, the animals were decapitated under basal conditions or exposed to a neurogenic (mild electrofootshocks) or systemic [i.v. lipopolysaccharide (LPS)] stimulus. PVN neuronal responses, indicated by changes in mRNA concentrations of the immediate early genes (IEGs) c-fos and NGFI-B, and plasma ACTH levels were measured before and during endotoxemia or electrofootshocks.

RESULTS

In the absence of alcohol, plasma ACTH and corticosterone remained at basal levels, indicating the absence of environment-induced stress. In rats exposed to alcohol, BALs were consistent and predictable, and we targeted peak values of about 200 mg%. At the end of the drug treatment period, there were no significant differences between CRF and VP receptor mRNA levels in the anterior pituitary of control and alcohol-treated rats. In contrast, alcohol treatment respectively decreased CRF and increased VP stores in the external zone of the median eminence. It also increased NGFI-B and c-fos transcripts in the magnocellular (m) portion of the PVN, but not the parvicellular (p) division of this nucleus under basal conditions (i.e., in the absence of shocks or LPS). After exposure to these stressors, on the other hand, all groups of rats showed significant increases in plasma ACTH levels as well as up-regulation of their PVN neuronal response, as indicated by changes in pPVN IEGs transcripts. However, these hormonal and neuronal responses were significantly blunted in animals pretreated with alcohol.

CONCLUSIONS

Collectively, our results suggest that decreased PVN neuronal activation represents an important mechanism of the ability of long-term alcohol treatment to blunt the ACTH response to shocks or endotoxemia. In addition, the new system of alcohol delivery that we developed is practical and reliable, and has the significant advantage that it enables measurement of circulating hormone levels during drug exposure of the animals.

Stroke-blind for colors, faces and locations: Partial recovery after three years

Purpose. To study and follow-up achromatopsia, prosopagnosia, and topographagnosia in a patient who suffered a bilateral stroke of the posterior cerebral arteries. Methods. Ophthalmological, neuropsychological and neuroradiological examinations were conducted over a span of 3 years to assess the amount of brain damage and look for signs of functional recovery. Results. After the onset of achromatopsia, perception of the color green re-appeared first, followed by red, yellow, and brown. Blue which had appeared entirely black was last to return. While reading and color naming have largely recovered, color discrimination after three years remains poor especially in dim lighting. Similarly, with prosopagnosia, while the patient has learn to identify people (including photographs) by individual features, his ability to perceive and recognize faces and facial expressions holistically remains severely impaired. Recognition of streets, houses, and topographical layouts also continues to be affected, while the perception of speed and distance has somewhat improved. Perimetry further suggests a mild improvement of the superior hemianopia in his visual fields. Conclusions. Although major deficits in color, face and place perception remain, some functions impaired by the stroke have returned par-alleling a partial recovery from the brain lesion as demonstrated by NMR.

A fluorescein angiographic study of branch retinal artery occlusion (BRAO) - the retrograde filling of occluded vessels

BACKGROUND

For assessing the prognosis of a branch retinal artery occlusion (BRAO), examination of the arterial blood flow by fluorescein angiography is necessary.

PATIENTS AND METHODS

In seven patients (mean age: 68.1, youngest 61, oldest 76 years old), with BRAO of varying involvement and extent, the disturbed retinal blood flow was demonstrated by this method. All the patients were subjected to Doppler sonography of the carotid arteries and all had a general medical examination.

RESULTS

The most impressive sign was the retrograde filling of the retinal arterial and/or venous branches from the adjacent retinal vessels and capillaries. In four patients the visual acuity was better after the disappearance of the retinal edema. In one patient the visual field defect slightly decreased at follow-up. This means that not every patient with retrograde filling of dye in BRAO has a bad prognosis in terms of visual function. The extent and duration of the retrograde filling with dye and the arterial or venous passage varied from patient to patient. There was also delayed filling with an increased period of retention in an artery (which is an adverse sign in BRAO), and retrograde filling of the corresponding vein. This latter came from small adjacent veins, but the retrograde filling of an artery came from capillaries or from very small adjacent arterioles. All the patients showed signs of general systemic disease, such as occlusion or the presence of plaques in the carotid artery, absolute arrhythmia, arterial hypertension, patent foramen ovale, diabetes mellitus, hyperuricemia, Factor V mutation, homocysteinemia or coronary heart disease.

CONCLUSION

Retrograde filling of the retinal arterial and/or venous branches means a kind of spontaneous healing compared to a condition with complete permanent obstruction of circulation. It is recommended that fluorescein angiography should be carried out for all patients with BRAO, in order to estimate the prognosis of the vascular occlusion. This is the first published record of consecutive pictures showing the retrograde filling of retinal arteries and/or veins with BRAO. In every patient with a BRAO an extensive medical and neurological examination (including echocardiography and Doppler sonography of the carotid arteries) is essential before planning the treatment.

Preferential cerebrospinal fluid acetylcholinesterase inhibition by rivastigmine in humans

This study sought to examine the feasibility of prolonged assessment of acetylcholinesterase (AChE) activity in the cerebrospinal fluid (CSF) of volunteers and to test the hypothesis that rivastigmine (ENA-713; Exelon, Novartis Pharma AG, Basel, Switzerland) selectively inhibits AChE in CSF in humans at a dose producing minimal inhibition of the peripheral enzyme. Lumbar CSF samples were collected continuously (0.1 mL x min(-1)) for 49 hours from eight healthy volunteers who took either placebo or a single oral dose of rivastigmine (3 mg). CSF specimens and samples of blood cells and blood plasma were analyzed at intervals for rivastigmine and its metabolite NAP 226-90 ([-] [3-([1-dimethylaminolethyl)-phenol]), erythrocyte AChE activity, CSF AChE activity, and plasma and CSF butyrylcholinesterase (BuChE) activity. Safety evaluations were performed 23 hours after drug dosing and at the end of the study. Evaluable data were obtained from six subjects. The mean time to maximal rivastigmine plasma concentration (tmax) was 0.83 +/- 0.26 hours, the mean maximal plasma concentration (Cmax) was 4.88 +/- 3.82 ng x mL(-1), the mean plasma area under the concentration versus time curve (AUC0-infinity) was 7.43 +/- 4.74 ng x hr x mL(-1), and the mean plasma t1/2 was 0.85 +/- 0.115 hours. The concentration of rivastigmine in CSF was lower than the quantification limit for assay (0.65 ng x mL(-1)), but NAP 226-90 reached a mean Cmax of 3.14 +/- 0.57 ng x mL(-1). Only minimal inhibition of erythrocyte AChE activity (approximately 3%) was observed. Inhibition of AChE in the CSF after rivastigmine administration was significantly greater than after placebo for up to 8.4 hours after the dose and was maximal (40%) at 2.4 hours. Plasma BuChE activity was significantly lower after rivastigmine than after placebo, but this was not clinically relevant. BuChE activity in CSF was significantly lower after rivastigmine than after placebo for up to 3.6 hours after dosing, but this difference was not sustained. This study confirms the feasibility of using continuous measurement of AChE activity in CSF over prolonged periods, that rivastigmine markedly inhibits CSF AChE after a single oral dose of 3 mg, and that the inhibition of central AChE is substantially greater than that of peripheral AChE or BuChE.

Assessment of the strength of individual 192Ir seeds in ribbons

Assessing the strength of individual seed-type sources in ribbon assembles remains a challenge in brachytherapy quality assurance. Geometries to measure a single source in the ribbon usually fail because of low signals if using very thick shielding to block the radiation from the other sources, or contributions from all the other sources if they are not shielded well. A normal well-type chamber with partial lead shielding forming a small slot provides a differential response along the chamber axis that, through a deconvolution/simultaneous-equations technique, sorts the contributions from each source, allowing the derivation of each source's strength.

Renal nuclear medicine: a review

Renal nuclear medicine is used to evaluate renal function and morphology. Renal scintigraphy is the best imaging modality for evaluation of functional parameters such as glomerular filtration rate and effective renal plasma flow. The commonly used renal radiopharmaceuticals are reviewed. Both imaging and non-imaging techniques are presented. Specific applications of renal nuclear medicine are discussed.

Teleimmersion for the doctor's office

The purpose of our research is the development of a new technology, teleimmersion, which will make possible 3D visual communication between people distributed over the globe. We are putting together a low-end, PC-based, affordable hardware system, and are developing the software for a teleimmersion node (T-node). The software is based on accurate polynocular stereo. We will describe a testbed for the system, show results, and discuss challenges for future research and implementation.

Neuronal correlates of encoding and retrieval in episodic memory during a paired-word association learning task: a functional magnetic resonance imaging study

The investigation of memory function using functional magnetic resonance imaging (fMRI) is an expanding field of research. The aim of this study was to demonstrate brain-activity patterns related to a word-pair association task employing a whole-brain EPI sequence. Six right-handed, healthy male volunteers (mean age: 27.5 years) took part in the study. fMRI was performed at a field strength of 1. 5 Tesla with 26-32 slices parallel to the AC-PC line, depending on individual brain size. Distributed brain regions were activated in episodic encoding and retrieval with similarities, but also (distinct) differences in activation patterns. Bilateral prefrontal cortical areas were involved when comparing encoding as well as retrieval to the reference condition (nonsense words). Furthermore, activation was observed in cerebellar areas during encoding, and activation in bilateral parietal areas (precuneus and inferior parietal cortex) was differentially more pronounced during retrieval. The activation of left dorsomedial thalamus during retrieval of high imagery-content word-pair associates may point to the role of this structure in episodic retrieval. The direct cognitive subtraction of encoding minus retrieval yielded a differentially larger left prefrontal activation. There was a differentially higher right prefrontal activation during retrieval than during encoding, underlining the proposed right/left asymmetry for episodic memory processes.

Pharmacological characterization of morphine-6-sulfate and codeine-6-sulfate

Morphine-6-sulfate (M6S) and codeine-6-sulfate (C6S) are mu-selective opiates which have been isolated from brain. M6S is an effective analgesic, with a 30-fold greater potency than morphine in the mouse radiant heat tailflick assay and similar to the active morphine metabolite morphine-6beta-glucuronide (M6G). M6S analgesia is reversed by 3-methoxynaltrexone at low antagonist doses which are inactive against morphine, suggesting that M6S may be acting through the same mechanisms as M6G. Consistent with this possibility, antisense mapping of the MOR-1 clone revealed that M6S analgesia was lowered by probes targeting exon 2 and not by targeting exon 1, a sensitivity profile similar to that of M6G and not morphine. C6S also has analgesic activity at doses approximately 10-fold greater than M6S. However, its characterization was impeded by the appearance of seizures at doses below full analgesic activity. Thus, M6S is a potent analgesic with pharmacological properties similar to M6G. C6S has limited utility due to its high level of toxicity.

Network analysis in episodic encoding and retrieval of word-pair associates: a PET study

The involvement of distributed brain regions in declarative memory has been hypothesized based on studies with verbal memory tasks. To characterize episodic declarative memory function further, 14 right-handed volunteers performed a visual verbal learning task using paired word associates. The volunteers underwent positron emission tomography. 15O-butanol was used as a tracer of regional cerebral blood flow (rCBF). Inter-regional functional interactions were assessed based on within-task, across-subject inter-regional rCBF correlations. Anatomical connections between brain areas were based on known anatomy. Structural equation modelling was used to calculate the path coefficients representing the magnitudes of the functional influences of each area on the ones to which it is connected by anatomical pathways. The encoding and the retrieval network elicit similarities in a general manner but also differences. Strong functional linkages involving visual integration areas, parahippocampal regions, left precuneus and cingulate gyrus were found in both encoding and retrieval; the functional linkages between posterior regions and prefrontal regions were more closely linked during encoding, whereas functional linkages between the left parahippocampal region and posterior cingulate as well as extrastriate areas and posterior cingulate gyrus were stronger during retrieval. In conclusion, these findings support the idea of a global bihemispheric, asymmetric encoding/retrieval network subserving episodic declarative memory. Our results further underline the role of the precuneus in episodic memory, not only during retrieval but also during encoding.

Pharyngeal pituitary: development, malformation, and tumorigenesis

The development of the pharyngeal pituitary (PhP) in the fetal period was morphologically and, for the first time, immunohistochemically examined. PhP, found in every individual, begins its hormone production at the 17-18th week of gestation, that is, 4-8 weeks later than that of sellar pituitary (SP). Only 1 of 25 examined fetuses without any stigmata of developmental anomalies showed a residual pituitary fragment in the craniopharyngeal canal (craniopharyngeal pituitary, CPhP). An adult case of a rare clivus pituitary adenoma that we examined is demonstrated in discussing its relationship to PhP. Extracranial ectopic pituitary adenomas in the literature describe an exclusively sphenoid sinus/nasopharyngeal/clivus location of the tumor. Their location corresponded exactly with that of PhP, so that the origin of the tumors can be reasonably speculated as PhP, although another origin, e.g., CPhP, can not be excluded. A variety of malformations of PhP, although very rare, have been described for the fist time during the systemic examination of 16 fetuses with different cranioneural malformations, such as agenesis, unseparated PhP from SP (pharyngosellar pituitary), fragmentation, and residual pituitary tissue in the open craniopharyngeal canal. However, developmental anomaly of PhP was not specifically associated with cranioneural malformations except in cases of chromosomal aberrations. The hormone production in PhP in malformation cases tended to be retarded. Absence of SP was recorded in 50% of anencephalics in the literature; however, PhP was identified in all anencephalics in our series, independent of the existence of SP. This supports the opinion that agenesis of SP in anencephalics seems to be false information.