Search PubMed⌕ Search

Biomedical subjects

M Lapidot

Publications and source records attributed to M Lapidot.

At least 19 recordsLinked to original sources
PubMed2005

Case report: multiple endocrine neoplasia type 2B misdiagnosed as familial dysautonomia.

BACKGROUND: Familial dysautonomia (FD) is a rare autosomal recessive disorder of the peripheral nervous system, affecting exclusively Jewish children of Ashkenazi extraction. The typical clinical features consist of somatic abnormalities: failure to thrive, characteristic facies, excessive sweating, labile blood pressure, recurrent aspiration pneumonias, lack of tears, and diminished and later absent deep tendon reflexes with generalized reduction of pain sensation. Oro-dental features include a lack of tongue fungiform papillae, impairment of taste, oro-dental self-mutilation, dental crowding, excessive plaque and calculus accumulation, salivary over production and low caries experience. CASE REPORT: A child with multiple endocrine neoplasia type 2B (MEN 2B) received, at the age of 11 months, an incorrect diagnosis of familial dysautonomia (FD). At the age of 6 years, a paediatric dentist experienced with FD noticed a normal number and shape of tongue fungiform papillae, while expecting to find a smooth tongue lacking those structures. The presence of numerous submucosal neuromata initiated a meticulous neurological and endocrine work-up, which established the diagnosis of MEN 2B. This led to an early detection and appropriate treatment of asymptomatic medullary thyroid carcinoma (MTC).

Adolescent↗
PubMed2002

[The current approach to hemangiomas and vascular malformations of the head and neck].

Though most hemangiomas do not need treatment, a significant minority are associated with complications and external deformities that demand intervention. Steroids play an important role in therapy, but not infrequently afford only partial and temporary benefit. Thanks to improvements in the surgical approach and equipment, hemostasis control devices and laser techniques, we can now treat patients who would otherwise go untreated. Moreover, in certain cases, we can now recommend earlier intervention, saving patients from years of living with deformities and the concomitant psychosocial problems. Vascular anomalies of the head and neck include venular, venous and arteriovenous malformations. These lesions are slow growing vascular ectasia that never involute spontaneously and almost always require intervention. Treatment includes laser therapy, injection of sclerosing agents, embolization through angiography and surgery, which in many cases is the only definitive treatment. We present the current treatment approach and describe our experience in the treatment of 16 patients.

Blood Vessels↗
PubMed2001

Mouse-human orthology relationships in an olfactory receptor gene cluster.

The olfactory receptor (OR) subgenome harbors the largest known gene family in mammals, disposed in clusters on numerous chromosomes. One of the best characterized OR clusters, located at human chromosome 17p13.3, has previously been studied by us in human and in other primates, revealing a conserved set of 17 OR genes. Here, we report the identification of a syntenic OR cluster in the mouse and the partial DNA sequence of many of its OR genes. A probe for the mouse M5 gene, orthologous to one of the OR genes in the human cluster (OR17-25), was used to isolate six PAC clones, all mapping by in situ hybridization to mouse chromosome 11B3-11B5, a region of shared synteny with human chromosome 17p13.3. Thirteen mouse OR sequences amplified and sequenced from these PACs allowed us to construct a putative physical map of the OR gene cluster at the mouse Olfr1 locus. Several points of evidence, including a strong similarity in subfamily composition and at least four cases of gene orthology, suggest that the mouse Olfr1 and the human 17p13.3 clusters are orthologous. A detailed comparison of the OR sequences within the two clusters helps trace their independent evolutionary history in the two species. Two types of evolutionary scenarios are discerned: cases of "true orthologous genes" in which high sequence similarity suggests a shared conserved function, as opposed to instances in which orthologous genes may have undergone independent diversification in the realm of "free reign" repertoire expansion.

Animals↗
PubMed2001

A dysfunctional movement protein of tobacco mosaic virus interferes with targeting of wild-type movement protein to microtubules.

The Tobacco mosaic virus (TMV) movement protein (MPTMV) mediates cell-to-cell viral trafficking by altering properties of the plasmodesmata (Pd) in infected cells. During the infection cycle, MPTMV becomes transiently associated with endomembranes, microfilaments, and microtubules (MT). It has been shown that the cell-to-cell spread of TMV is reduced in plants expressing the dysfunctional MP mutant MPNT-1. To expand our understanding of the MP function, we analyzed events occurring during the intracellular and intercellular targeting of MPTMV and MPNT-1 when expressed as a fusion protein to green fluorescent protein (GFP), either by biolistic bombardment in a viral-free system or from a recombinant virus. The accumulation of MPTMV:GFP, when expressed in a viral-free system, is similar to MPTMV:GFP in TMV-infected tissues. Pd localization and cell-to-cell spread are late events, occurring only after accumulation of MP:GFP in aggregate bodies and on MT in the target cell. MPNT-1:GFP localizes to MT but does not target to Pd nor does it move cell to cell. The spread of transiently expressed MPTMV:GFP in leaves of transgenic plants that produce MPNT-1 is reduced, and targeting of the MPTMV:GFP to the cytoskeleton is inhibited. Although MPTMV:GFP targets to the Pd in these plants, it is partially impaired for movement. It has been suggested that MPNT-1 interferes with host-dependent processes that occur during the intracellular targeting program that makes MP movement competent.

Cucumis sativus↗
PubMed2001

An early tobacco mosaic virus-induced oxidative burst in tobacco indicates extracellular perception of the virus coat protein.

Induction of reactive oxygen species (ROS) was observed within seconds of the addition of exogenous tobacco mosaic virus (TMV) to the outside of tobacco (Nicotiana tabacum cv Samsun NN, EN, or nn) epidermal cells. Cell death was correlated with ROS production. Infectivity of the TMV virus was not a prerequisite for this elicitation and isolated coat protein (CP) subunits could also elicit the fast oxidative burst. The rapid induction of ROS was prevented by both inhibitors of plant signal transduction and inhibitors of NAD(P)H oxidases, suggesting activation of a multi-step signal transduction pathway. Induction of intracellular ROS by TMV was detected in TMV-resistant and -susceptible tobacco cultivars isogenic for the N allele. The burst was also detected with strains of virus that either elicit (ToMV) or fail to elicit (TMV U1) N' gene-mediated responses. Hence, early ROS generation is independent or upstream of known genetic systems in tobacco that can mediate hypersensitive responses. Analysis of other viruses and TMV CP mutants showed marked differences in their ability to induce ROS showing specificity of the response. Thus, initial TMV-plant cell interactions that lead to early ROS induction occur outside the plasma membrane in an event requiring specific CP epitopes.

Capsid↗
PubMed2000

Genetic mapping of the Tsw locus for resistance to the Tospovirus Tomato spotted wilt virus in Capsicum spp. and its relationship to the Sw-5 gene for resistance to the same pathogen in tomato.

The Tsw gene conferring dominant resistance to the Tospovirus Tomato spotted wilt virus (TSWV) in Capsicum spp. has been tagged with a random amplified polymorphic DNA marker and mapped to the distal portion of chromosome 10. No mapped homologues of Sw-5, a phenotypically similar dominant TSWV resistance gene in tomato, map to this region in C. annuum, although a number of Sw-5 homologues are found at corresponding positions in pepper and tomato. The relationship between Tsw and Sw-5 was also examined through genetic studies of TSWV. The capacity of TSWV-A to overcome the Tsw gene in pepper and the Sw-5 gene in tomato maps to different TSWV genome segments. Therefore, despite phenotypic and genetic similarities of resistance in tomato and pepper, we infer that distinct viral gene products control the outcome of infection in plants carrying Sw-5 and Tsw, and that these loci do not appear to share a recent common evolutionary ancestor.

Capsicum↗
PubMed2000

Pernicious anemia, gastric carcinoid, and autoimmune thrombocytopenia in a young woman.

The association between gastric carcinoid tumors and pernicious anemia is well recognized. Such tumors occur in the presence of achlorhydria, chronic atrophic gastritis, hypergastrinemia, and enterochromaffin-like cell hyperplasia. In this case report, a 29-year-old woman with pernicious anemia and autoimmune thrombocytopenia who developed gastric carcinoid tumors of the gastric body is described. This is the second description of pernicious anemia associated with autoimmune thrombocytopenia. This association in a young woman together with the therapeutic options and decisions that were taken in the treatment of the patient are discussed.

Adult↗
PubMed1998

Ocular manifestations in multiple endocrine neoplasia type 2b.

PURPOSE: To describe the clinical and laboratory findings in a patient with multiple endocrine neoplasia type 2b. METHOD: Case report. An 8-year-old boy underwent ophthalmic examination, genetic evaluation, total thyroidectomy, and biopsy of a tongue nodule. RESULTS: Ocular features, including previously unreported iris changes, and their probable origin are discussed. Genetic testing detected the point mutation at codon 918 within the RET protooncogene on chromosome 10, characteristic of multiple endocrine neoplasia type 2b. Histologic analysis of excised thyroid tissue disclosed medullary carcinoma. A tongue nodule proved to be neuromatous. CONCLUSION: Ophthalmologists can play an important role in the recognition of multiple endocrine neoplasia type 2b, a potentially lethal condition.

Carcinoma, Medullary↗
PubMed1998

Domains of the TMV movement protein involved in subcellular localization.

To identify and map functionally important regions of the tobacco mosaic virus movement protein, deletions of three amino acids were introduced at intervals of 10 amino acids throughout the protein. Mutations located between amino acids 1 and 160 abolished the capacity of the protein to transport virus from cell to cell, while some of the mutations in the C-terminal third of the protein permitted function. Despite extensive tests, no examples were found of intermolecular complementation between mutants, suggesting that function requires each movement protein molecule to be fully competent. Many of the mutants were fused to green fluorescent protein, and their subcellular localizations were determined by fluorescence microscopy in infected plants and protoplasts. Most mutants lost the ability to accumulate in one or more of the multiple subcellular sites targeted by wild-type movement protein, suggesting that specific functional domains were disrupted. The order in which accumulation at subcellular sites occurs during infection does not represent a targeting pathway. Association of the movement protein with microtubules or with plasmodesmata can occur in the absence of other associations. The region of the protein around amino acids 9-11 may be involved in targeting the protein to cortical bodies (probably associated with the endoplasmic reticulum) and to plasmodesmata. The region around residues 49-51 may be involved in co-alignment of the protein with microtubules. The region around residues 88-101 appears to play a role in targeting to both the cortical bodies and microtubules. Thus, the movement protein contains independently functional domains.

Amino Acid Sequence↗
PubMed1997

Cys 618 Arg mutation in the RET proto-oncogene associated with familial medullary thyroid carcinoma and maternally transmitted Hirschsprung's disease suggesting a role for imprinting.

The multiple endocrine neoplasia type 2 (MEN2) syndromes and Hirschsprung's disease (HSCR) are inherited neurocristopathies characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, parathyroid disease, and gastrointestinal neuromatosis. Mutations in the RET proto-oncogene are the underlying cause of the MEN2 syndromes and some cases of HSCR. In this report, we show that Cys 618 Arg mutation cosegregates with familial MTC and HSCR in two Moroccan Jewish families in which no involvement of pheochromocytoma or parathyroidism was observed. A single haplotype shared by chromosomes bearing the Cys 618 Arg mutation in both families strongly suggests a founder effect for this mutation. We have observed in our and in several other previously reported families, an excess of maternal over paternal mutated RET alleles in offsprings affected by HSCR. We suggest that parental imprinting may play a role in the ethiology of HSCR caused by mutations in the RET protooncogene.

Arginine↗
PubMed1996

Differences in susceptibility to the "blending illusion" among Native Hebrew and English speakers.

This study was designed to explore whether native Hebrew and English speakers differ in their susceptibility to the blend illusion and in their lip-reading of words and cliché sentences. Four lip-reading tests, designed to assess recognition of syllables, words, and overlearned sentences, were administered to two groups of subjects who were matched for age, sex, and educational level. The English-speaking group showed significantly higher susceptibility to the blending illusion. The source of the effect was in the enhanced sensitivity to the auditory input in males along with reduced number of auditory biases in females. No sex differences in lip-reading of any item of the lip-reading battery was obtained in native Hebrew speakers. Subjects in both groups performed at the same level in recognizing the words and overlearned sentences. The result is attributed to the shorter Voice Onset Time values of Hebrew when native listeners would hear acoustic messages prior to discernable lip movements.

Adult↗
PubMed1995

A defective movement protein of TMV in transgenic plants confers resistance to multiple viruses whereas the functional analog increases susceptibility.

Transgenic tobacco plants that express a gene encoding a defective mutant of the tobacco mosaic virus (TMV) movement protein which are known to be resistant to several tobamoviruses were inoculated with viruses from different taxonomic groups to determine the breadth of resistance. There were significant delays in the time of appearance of disease symptoms and/or there was reduced systemic accumulation of virus in upper leaves of plants inoculated with tobacco rattle tobravirus, tobacco ringspot nepovirus, alfalfa mosaic alfamovirus, peanut chlorotic streak caulimovirus, and cucumber mosaic cucumovirus. Conversely, tobacco plants that express a gene encoding the functional tobacco mosaic virus wild-type movement protein accelerated symptom development, enhanced the severity of symptom formation, and/or increased the accumulation of these viruses and, additionally, TMV. Our results indicate that there are similar functions among the movement proteins of a number of plant viruses despite the apparent lack of sequence similarity between them.

Mosaic Viruses↗
PubMed1995

High incidence of occult thyroid disease among general medical ward patients.

The objective of this study was to prospectively determine the efficacy of the results of routine testing of thyroid functions in patients admitted to a general medical ward. Blood for thyroid function tests was drawn on admission as part of the laboratory screening panel from 270 consecutive patients. Fifty-one were excluded due to recognition of thyroid-related problems by the clinical staff. 138 patients (63%) had normal free thyroxin (FT4) levels, one patient had hyperthyroidism, 15 patients (6.8%) had laboratory primary hypothyroidism and 65 patients (29.6%) had equivocal results (FT4 < 0.9 ng/dL and TSH < 5.0 mmu/L). In eight out of 31 patients in the latter group, the thyroid releasing hormone (TRH) test revealed primary or secondary hypothyroidism. A total of 55 patients (25.1%) expired within one year. The mortality rate was significantly higher among the low FT4 patients (p < 0.01), and was independent of age and sex. We conclude that inclusion of FT4 in a laboratory screening panel will reveal a large patient population with abnormal results. However, establishing the diagnosis requires additional tests. Therefore, screening for occult hypothyroidism among a select population, not the acutely sick, populations may be more efficient.

Adult↗
PubMed1994

Somatostatin-receptor imaging of medullary thyroid carcinoma.

In-111 pentetreotide scintigraphy of 10 patients with residual or metastatic medullary thyroid carcinoma is described. Six patients had sporadic tumor and 4 had MEN IIB. Foci of increased tracer uptake were observed in 9 patients: in the thyroid bed (4 patients), the mediastinum (3 patients.), the shoulder area and left lower abdomen (1 patient), and the left upper abdomen (1 patient). The 10th patient had no abnormal uptake. CT confirmed 2 mediastinal lesions and 2 out of 3 thyroid masses, but did not detect the thyroid remnants or the lesions in the shoulder area and abdomen. Lung lesions < or = 1 cm in diameter and ill-defined liver foci (2 patients) were seen on CT, but not on scintigraphy. Small liver metastases not demonstrated on CT or on scintigraphy were identified at surgery in a MEN IIB patient. Elevated urinary epinephrine was found in 2 out of 4 MEN IIB patients. In one, tracer uptake in the left adrenal corresponded to a mass on CT, to pathological uptake of MIBG and DMSA, and to a tumor removed at surgery. The second patient had peritoneal spread of malignant pheochromocytoma (at surgery), but negative CT and only a single focus in the left lower abdomen on scintigraphy. Somatostatin-receptor imaging is useful for the detection of residual and recurrent medullary thyroid carcinoma, and may identify pheochromocytoma in MEN IIB patients.

Adrenal Gland Neoplasms↗
PubMed1992

Electroconvulsive therapy for persistent neuroleptic-induced akathisia and parkinsonism: a case report.

Neuroleptic-induced akathisia (NIA) and parkinsonism (NIP) continued for 3 months, despite two courses of anticholinergic treatments, a shift to low-potent neuroleptic (NL) and a NL-free period. The two adverse effects responded dramatically to electroconvulsive therapy (ECT) to reemerge 3 months after termination of ECT. The case supports the idea that ECT is effective for both NIA and NIP even when they are resistant.

Adult↗