Multi-scale analysis of optic chiasmal compression by finite element modelling

The precise mechanism of bitemporal hemianopia (a type of partial visual field defect) is still not clear. Previous work has investigated this problem by studying the biomechanics of chiasmal compression caused by a pituitary tumour growing up from below the optic chiasm. A multi-scale analysis was performed using finite element models to examine both the macro-scale behaviour of the chiasm and the micro-scale interactions of the nerve fibres within it using representative volume elements. Possible effects of large deflection and non-linear material properties were incorporated. Strain distributions in the optic chiasm and optic nerve fibres were obtained from these models. The results of the chiasmal model agreed well with the limited experimental results available, indicating that the finite element modelling can be a useful tool for analysing chiasmal compression. Simulation results showed that the strain distribution in nasal (crossed) nerve fibres was much more nonuniform and locally higher than in temporal (uncrossed) nerve fibres. This strain difference between nasal and temporal nerve fibres may account for the phenomenon of bitemporal hemianopia.     

The indications for and the role of depth electrode recording in epilepsy

A series of 47 patients studied with stereotactically implanted depth electrodes is analyzed. Indications and grouping of the patients fall into three main categories: (a) the bitemporal series (35 patients) where there is ambiguity as to the lateralization of the focus; (b) the unilateral series (6 patients) where the problem is one of localization within one hemisphere, and (c) the generalized series where one tries to determine the primary focus in secondary generalized seizures (6 patients). The best indication appears to be the bitemporal cases, in which a large number of attacks can be recorded by computer. Most of them tend to have a well-lateralized onset in one of the temporal lobes; 32 of the 35 implanted patients were operated upon (91.4%). The results on the seizure tendency in these patients is comparable, if not superior, to those obtained in the so-called unilateral cases. Correlation studies indicate that interictal activity is a good indicator of the predominance of seizures.     

Pulmonary Atypical Carcinoid Tumor with Metastatic Involvement of the Pituitary Gland Causing Functional Hypopituitarism

ObjectiveTo report a unique case of a peripherally located pulmonary atypical carcinoid tumor with metastatic involvement of the pituitary, manifesting with evidence of functional hypopituitarism and compressive symptoms of dysarthria, bitemporal loss of vision, and ataxia.MethodsWe present a case report, including detailed laboratory, radiologic, and pathologic findings in a 50-year-old woman with a peripherally located pulmonary atypical carcinoid tumor and a lesion metastatic to the pituitary gland. The pertinent literature is also reviewed.ResultsA 50-year-old woman with a medical history of metastatic pulmonary atypical carcinoid tumor presented with symptoms of bitemporal hemianopia, ataxia, and dysarthria. Laboratory evaluation revealed functional hypopituitarism, and magnetic resonance imaging of the brain with use of gadolinium contrast demonstrated a pituitary lesion measuring 3.5 by 2.5 by 2.5 cm. Visual field testing revealed bitemporal superior quadrantanopia, consistent with a pituitary lesion of the chiasm. Computed tomographic angiography excluded the presence of an aneurysm of the internal carotid artery. Subsequently, the patient underwent subtotal transsphenoidal hypophysectomy. Findings on pathology examination were consistent with a lesion metastatic from the primary pulmonary atypical carcinoid tumor. The patient subsequently received monthly octreotide injections as well as chemotherapeutic regimens of capecitobine and temozolomide. At 18-month follow-up, disease had not recurred.ConclusionThis case of metastatic involvement of the pituitary gland from a peripherally located pulmonary atypical carcinoid tumor manifesting with evidence of functional hypopituitarism is highly uncommon. To our knowledge, such a case has not been previously reported. The presentation of an advanced pituitary metastatic lesion can be particularly dramatic, and the course can be potentially complicated. Therefore, heightened awareness of the possibility of a pituitary lesion metastatic from a pulmonary atypical carcinoid tumor is important. (Endocr Pract. 2007;13:291-295)     

Pregnancy,prolactin, and pituitary tumours

Nine pregnancies are described in patients with pituitary tumours. All patients had definite radiological evidence of a pituitary tumour and no evidence of acromegaly or Cushing''s disease. In seven patients serum prolactin levels were estimated before pregnancy and found to be raised.Seven patients had been treated with pituitary implantation of yttrium-90. The remaining two developed complications of the tumour during pregnancy. One developed a bitemporal visual field defect in the second trimester which was successfully treated by emergency yttrium-90 implantation. The other developed diabetes insipidus in the third trimester which resolved spontaneously after delivery.Six patients were treated with drugs to achieve pregnancy. Four took bromocriptine to suppress raised prolactin levels, one was treated with human menopausal gonadotrophin, and one was treated with clomiphene.     

Modifications in the surgical correction of trigonocephaly

A modified technique for the surgical correction of trigonocephaly is presented. The technical modifications are designed both to increase the stability of fixation of the supraorbital bar and lateral canthal advancements and to increase interorbital distance and anterior cranial fossa volume when utilized in those patients who exhibit the full expression of trigonocephaly, including midline ridging, bifrontal recession, hypotelorbitism, shortened anterior cranial fossa, deficient projection of lateral orbit, and bitemporal narrowing. It is a modification of the supraorbital bar remodeling/advancement procedure as originally described by Marchac with the introduction of a nasofrontal osteotomy and superior osteotomy bone graft and midline miniplate fixation of the supraorbital bar to the nasofrontal junction. Its use in 20 patients has been favorable.     

The place of stereotactic depth electrode recording in epilepsy

A series of 70 patients studied with stereotactically implanted depth electrodes is analyzed. Indications and grouping fall into three main categories: the bitemporal series (52 patients), where there is ambiguity as to the lateralization of the focus; the unilateral series (6 patients), where the main problem is one of localization within one hemisphere, and the generalized and/or multifocal series (12 patients), where a primary focus is suspected. The best indication is represented by the group of 'bitemporal cases' which turned out to have a well-lateralized onset with intracerebral recording.     

Allan-Herndon syndrome. I. Clinical studies.

A large family with X-linked mental retardation, originally reported in 1944 by Allan, Herndon, and Dudley, has been reinvestigated. Twenty-nine males have been affected in seven generations. Clinical features include severe mental retardation, dysarthria, ataxia, athetoid movements, muscle hypoplasia, and spastic paraplegia with hyperreflexia, clonus, and Babinski reflexes. The facies appear elongated with normal head circumference, bitemporal narrowing, and large, simple ears. Contractures develop at both small and large joint. Statural growth is normal and macroorchidism does not occur. Longevity is not impaired. High-resolution chromosomes, serum creatine kinase, and amino acids are normal. This condition, termed the Allan-Herndon syndrome, appears distinct from other X-linked disorders having mental retardation, muscle hypoplasia, and spastic paraplegia.     

Event-related potentials to faces: the effects of priming and recognition

Short-term visual memory, as in both implicit priming and explicit recognition tasks, can be demonstrated by decreased reaction times, the ability to preferentially select previously presented objects from lists and the ability to more readily complete previously exposed words from fragmented letters. The visual processing of faces occurs separately from the visual processing of non-face stimuli, within discrete areas of bilateral posterior inferotemporal cortices. While visual recognition and memory of faces are independent of those for non-faces, their processing appears to be similar. We have demonstrated an electrophysiologic correlate of short-term visual memory in a face-matching paradigm. We have observed a series of evoked potential components consisting predominantly of a C140, C180 and C240 with a posterior, bitemporal distribution. The priming effect is reflected by a diminution of C240 amplitude in the response to repeated pictures of faces compared to novel pictures of faces. These data reflect a previously unreported set of neurophysiological observations on short-term visual memory for faces.     

Clinical and molecular diagnosis of Miller-Dieker syndrome.

We report results of clinical, cytogenetic, and molecular studies in 27 patients with Miller-Dieker syndrome (MDS) from 25 families. All had severe type I lissencephaly with grossly normal cerebellum and a distinctive facial appearance consisting of prominent forehead, bitemporal hollowing, short nose with upturned nares, protuberant upper lip, thin vermilion border, and small jaw. Several other abnormalities, especially growth deficiency, were frequent but not constant. Chromosome analysis showed deletion of band 17p13 in 14 of 25 MDS probands. RFLP and somatic cell hybrid studies using probes from the 17p13.3 region including pYNZ22 (D17S5), pYNH37 (D17S28), and p144-D6 (D17S34) detected deletions in 19 of 25 probands tested including seven in whom chromosome analysis was normal. When the cytogenetic and molecular data are combined, deletions were detected in 21 of 25 probands. Parental origin of de novo deletions was determined in 11 patients. Paternal origin occurred in seven and maternal origin in four. Our demonstration of cytogenetic or molecular deletions in 21 of 25 MDS probands proves that deletion of a "critical region" comprising two or more genetic loci within band 17p13.3 is the cause of the MDS phenotype. We suspect that the remaining patients have smaller deletions involving the proposed critical region which are not detected with currently available probes.     

Intraoperative cytologic diagnosis of symptomatic carcinoma (pulmonary small cell carcinoma) metastatic to the pituitary gland: a case report

BACKGROUND: Carcinoma metastatic to the pituitary gland is infrequent and has been reportedly detected in approximately 1% of pituitary surgical cases. It may masquerade as a pituitary adenoma both clinically and radiologically. CASE: A 49-year-old man presented with a 1-month history of severe headache, diplopia and blurred vision. Neurologic examination revealed bitemporal hemianopsia and left sixth nerve palsy. The initial radiologic diagnosis based on magnetic resonance imaging was pituitary adenoma. A biopsy of the lesion was performed. While intraoperative frozen section examination could not completely exclude an "atypical" pituitary adenoma, cytologic touch imprint findings were diagnostic of metastatic small cell carcinoma. Subsequently, additional workup revealed that the patient had a mass lesion in the right lung and right-sided mediastinal lymphadenopathy on chest computed tomography. This was a rare case of pituitary metastasis as the first manifestation of an occult malignancy. CONCLUSION: For intraoperative diagnosis at the time ofpituitary surgery, cytologic imprints can be used reliably to make a diagnosis not only of pituitary adenoma but also of metastatic lesions. It is appropriate in current neuropathology practice that the imprint method be used as the sole modality for intraoperative consultation for pituitary lesions.     

Some Clues and Pitfalls in the Diagnosis of Acromegaly

ObjectiveTo describe a case of acromegaly in a young woman using oral contraceptives who had nonspecific symptoms and persistent hyperphosphatemia and to analyze the reasons for delay in diagnosis.MethodsA 31-year-old woman underwent evaluation for failure of menstrual flow to resume after discontinued use of oral contraceptives. Clinical and laboratory findings are summarized, and atypical manifestations of acromegaly are discussed.ResultsThe patient complained of weight gain, acne, and increased facial hair growth, and laboratory tests showed a low estradiol level and hyperinsulinemia. “Postpill amenorrhea” and polycystic ovary syndrome were considered possible diagnoses. During subsequent endocrinology consultation, hyperphosphatemia was present on three occasions during a 7-month period. Hormonal studies for evaluation of pituitary function revealed increased insulin-like growth factor-I and growth hormone (GH) levels. Acromegaly was suspected, and the increased GH level failed to suppress after a glucose load. Magnetic resonance imaging revealed a pituitary macroadenoma with suprasellar extension. Visual field testing showed bitemporal abnormalities. Transsphenoidal resection successfully removed the GH-producing tumor, and hormone replacement therapy was initiated postoperatively.ConclusionThe textbook presentation of GH excess is a late feature of acromegaly. The diagnosis in a young woman can be easily missed when clinicopathologic findings are not classic and the picture is further clouded by factors such as oral contraceptive use. Features may also resemble polycystic ovary syndrome, a more common condition in women of childbearing age. This case also illustrates that hyperphosphatemia, overlooked in this patient, can precede the full-blown clinical manifestations of acromegaly and serve as a subtle clue to the underlying disease. Awareness of these situations and screening for high GH levels in patients with unexplained, persistent hyperphosphatemia are advisable for making an early correct diagnosis and providing appropriate therapy. (Endocr Pract. 2004;10:348-352)     

Septo-optic dysplasia as a manifestation of valproic acid embryopathy.

BACKGROUND: The use of valproic acid during pregnancy has been associated with adverse fetal outcomes, including major and minor congenital malformations, intrauterine growth retardation (IUGR), hyperbilirubinemia, hepatotoxicity, transient hyperglycemia, and fetal and neonatal distress. In addition, intrauterine exposure to valproic acid has been associated with an increased risk of central nervous system abnormalities, primarily neural tube defects. Optic nerve hypoplasia has been reported in association with other prenatal anticonvulsant exposures, but the occurrence of septo-optic dysplasia as a manifestation of valproic acid embryopathy has not been reported previously. RESULTS: We report on a woman who received Depakote (valproic acid) throughout her pregnancy for the treatment of a seizure disorder. The patient presented with features typical of valproic acid embryopathy, including bitemporal narrowing, hypertelorism, short palpebral fissures, epicanthal folds, microphthalmia, a flat broad nasal bridge, small mouth, hypoplastic nails, mild clinodactyly, and camptodactyly. MRI showed hypoplasia of the optic chiasm and absence of the septum pellucidum. CONCLUSIONS: We report the first case of septo-optic dysplasia associated with maternal exposure to valproic acid throughout pregnancy. This case expands the clinical phenotype of valproate embryopathy.     

Thyrotropin-Secreting Adenoma in a Patient with Primary Hypothyroidism

ObjectiveTo describe a patient who developed a thyrotropin (TSH)-Secreting adenoma in the setting of primary hypothyroidism.MethodsWe report the clinical, laboratory, and radiologic findings of a patient with a history of primary hypothyroidism who presented with headache, a bitemporal visual field deficit, and elevated TSH despite long-term levothyroxine therapy. We discuss the diagnostic challenges of this case and review the relevant literature.ResultsA54-year-old woman with a history of primary hypothyroidism presented with a 3-year history of headache and a week of worsening vision. Imaging revealed a heterogeneous sellar mass elevating the optic chiasm. Her serum TSH was 46.5 mIU/L and free thyroxine concentration was 0.1 ng/dL. The differential diagnosis included pituitary hyperplasia and a TSH-secreting adenoma in a patient with primary hypothyroidism. The pathologic characteristics of the tumor were consistent with the latter.ConclusionIn a patient with an elevated TSH concentration and a previous diagnosis of hypothyroidism, it is important to consider other entities besides medication noncompliance. TSH-secreting adenomas can also cause elevated levels of TSH. (Endocr Pract. 2011;17: e135-e139)     

Visual field defects of optic neuritis in neuromyelitis optica compared with multiple sclerosis

Background

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease that predominantly affects the optic nerves and the spinal cord, and is possibly mediated by an immune mechanism distinct from that of multiple sclerosis (MS). Central scotoma is recognized as a characteristic visual field defect pattern of optic neuritis (ON), however, the differing pathogenic mechanisms of NMO and MS may result in different patterns of visual field defects for ON.

Methods

Medical records of 15 patients with NMO and 20 patients with MS having ON were retrospectively analyzed. A thorough systemic and neurological examination was performed for evaluating ON. The total number of relapses of ON and visual fields was investigated. Visual fields were obtained by Goldmann perimeter with each ON relapse.

Results

All MS patients experienced central scotoma, with 90% of them showing central scotoma with every ON relapse. However, 53% of NMO patients showed central scotoma with every ON relapse (p = 0.022), and the remaining 47% of patients experienced non-central scotoma (altitudinal, quadrant, three quadrant, hemianopia, and bitemporal hemianopia). Thirteen percent of NMO patients did not experience central scotoma during their disease course. Altitudinal hemianopia was the most frequent non-central scotoma pattern in NMO.

Conclusions

NMO patients showed higher incidence of non-central scotoma than MS, and altitudinal hemianopia may be characteristic of ON occurring in NMO. As altitudinal hemianopia is highly characteristic of ischemic optic neuropathy, we suggest that an ischemic mechanism mediated by anti-aquaporin-4 antibody may play a role in ON in NMO patients.

     

Identifying and managing adverse environmental health effects: 1. Taking an exposure history

PUBLIC CONCERN AND AWARENESS ARE GROWING about adverse health effects of exposure to environmental contaminants. Frequently patients present to their physicians with questions or concerns about exposures to such substances as lead, air pollutants and pesticides. Most primary care physicians lack training in and knowledge of the clinical recognition, management and avoidance of such exposures. We have found that it can be helpful to use the CH²OPD² mnemonic (Community, Home, Hobbies, Occupation, Personal habits, Diet and Drugs) as a tool to identify a patient''s history of exposures to potentially toxic environmental contaminants. In this article we discuss why it is important to take a patient''s environmental exposure history, when and how to take the history, and how to interpret the findings. Possible routes of exposure and common sources of potentially toxic biological, physical and chemical substances are identified. A case of sick-building syndrome is used to illustrate the use of the mnemonic.CaseA 40-year-old married bookkeeper presents with a 3-year history of headaches. She describes having “tight,” bitemporal headaches almost daily that resolve after taking three 325-mg tablets of ASA. She also complains of a “spacey” feeling, difficulty concentrating and remembering, fatigue, a stuffy nose and a full feeling in her ears. Her symptoms improve on weekends and over the holidays and seem to be worse in the winter. Over the past 2 years she has noticed that she gets a stuffy nose and headaches when exposed to perfumes, tobacco smoke and automobile exhaust. Her past medical history is remarkable only for infantile eczema. Her family history is unremarkable other than her mother having hypothyroidism. She is taking no medications other than ASA, does not smoke, reports having no allergies and says she is happily married with no major family, financial or social concerns. She enjoys her work and coworkers. On physical examination she has puffy, dark circles under her eyes, there is loss of light reflex on her left ear drum, and her nasal mucosa appears edematous and erythematous. There are multiple excoriated, erythematous papules 5 mm in diameter on her face, anterior chest and anterior lower legs.Questions surrounding this case: What is sick-building syndrome and how do patients commonly present? What causes or contributes to sick-building syndrome? What are the risk factors? How should cases be managed?     

Dominant Mutations in KAT6A Cause Intellectual Disability with Recognizable Syndromic Features

Through a multi-center collaboration study, we here report six individuals from five unrelated families, with mutations in KAT6A/MOZ detected by whole-exome sequencing. All five different de novo heterozygous truncating mutations were located in the C-terminal transactivation domain of KAT6A: {"type":"entrez-nucleotide","attrs":{"text":"NM_001099412.1","term_id":"150378462","term_text":"NM_001099412.1"}}NM_001099412.1: c.3116_3117 delCT, p.(Ser1039^∗); c.3830_3831insTT, p.(Arg1278Serfs^∗17); c.3879 dupA, p.(Glu1294Argfs^∗19); c.4108G>T p.(Glu1370^∗) and c.4292 dupT, p.(Leu1431Phefs^∗8). An additional subject with a 0.23 MB microdeletion including the entire KAT6A reading frame was identified with genome-wide array comparative genomic hybridization. Finally, by detailed clinical characterization we provide evidence that heterozygous mutations in KAT6A cause a distinct intellectual disability syndrome. The common phenotype includes hypotonia, intellectual disability, early feeding and oromotor difficulties, microcephaly and/or craniosynostosis, and cardiac defects in combination with subtle facial features such as bitemporal narrowing, broad nasal tip, thin upper lip, posteriorly rotated or low-set ears, and microretrognathia. The identification of human subjects complements previous work from mice and zebrafish where knockouts of Kat6a/kat6a lead to developmental defects.     

生物柴油的应用研究进展

综述了国内外生物柴油的应用和生产现状,介绍了生物柴油的主要特性以及直接混合、微乳液、高温热裂解、化学酯交换、生物酶催化和超临界甲醇法等生产生物柴油的方法,阐述了我国发展生物柴油的重要意义,并提出了我国发展生物柴油技术的建议。     

The effect of the UV microirradiation of the centrosome on cell behavior. III. The ultrastructure of the centrosome after irradiation]

One of the spindle poles of mitotic PK cells was irradiated with UV microbeam in metaphase or in anaphase. Electron microscopy showed that immediately after irradiation the microtubules around the centrosome were maintained, and that the ultrastructure of both irradiated and nonirradiated poles was similar. After microirradiation of the centrosome in metaphase, the mitotic halo around this centrosome was retained, but in due time the number of microtubules was getting less compared to that around the nonirradiated centrosome. When daughter cells with irradiated centrosomes are passing into the interphase, their centrioles are not separated from each other, no primary cilia are formed, and no replication of centrioles occurs. In the interphase cells with irradiated centrosomes, satellites are formed on the active centriole, but centrosome-attached microtubules are practically absent.