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Biomedical subjects

R Amit

Publications and source records attributed to R Amit.

At least 19 recordsLinked to original sources
PubMed2001

Compaction of single DNA molecules induced by binding of integration host factor (IHF).

We studied the interaction between the integration host factor (IHF), a major nucleoid-associated protein in bacteria, and single DNA molecules. Force-extension measurements of lambda DNA and an analysis of the Brownian motion of small beads tethered to a surface by single short DNA molecules, in equilibrium with an IHF solution, indicate that: (i) the DNA-IHF complex retains a random, although more compact, coiled configuration for zero or small values of the tension, (ii) IHF induces DNA compaction by binding to multiple DNA sites with low specificity, and (iii) with increasing tension on the DNA, the elastic properties of bare DNA are recovered. This behavior is consistent with the predictions of a statistical mechanical model describing how proteins bending DNA are driven off by an applied tension on the DNA molecule. Estimates of the amount of bound IHF in DNA-IHF complexes obtained from the model agree very well with independent measurements of this quantity obtained from the analysis of DNA-IHF crosslinking. Our findings support the long-held view that IHF and other histone-like proteins play an important role in shaping the long-scale structure of the bacterial nucleoid.

Bacterial Proteins↗
PubMed1999

High-resolution holocene environmental changes in the thar desert, northwestern india

Sediments from Lunkaransar dry lake in northwestern India reveal regional water table and lake level fluctuations over decades to centuries during the Holocene that are attributed to changes in the southwestern Indian monsoon rains. The lake levels were very shallow and fluctuated often in the early Holocene and then rose abruptly around 6300 carbon-14 years before the present (14C yr B.P.). The lake completely desiccated around 4800 (14)C yr B.P. The end of this 1500-year wet period coincided with a period of intense dune destabilization. The major Harrapan-Indus civilization began and flourished in this region 1000 years after desiccation of the lake during arid climate and was not synchronous with the lacustral phase.

Journal Article↗
PubMed1995

How long to treat childhood onset absence epilepsy.

The relation between the duration of treatment and achievement of seizure-free state after stopping medication in childhood onset absence epilepsy (COAE) has not been established, and children are usually treated for periods of 2-4 years. We hypothesized that a group of patients defined by prompt total clinical and electrographic remission, verified by 24-hour ambulatory EEG, could be withdrawn from treatment without recurrence. Three patients with new onset of COAE were treated. Ethosuximide (ESM) was used as first line drug. Dosages correlated with blood levels were gradually increased until a clinical and electrographic seizure-free state was achieved. The three responded to ESM promptly at therapeutic blood levels (75-90 mcg/ml). The effects of a 5- to 6-week period of withdrawing ESM after 6 months of treatment were as follows: a 10-year-old boy remained seizure-free with recurrence of inter-ictal 3/second spike-wave bursts; 5- and 10-year-old girls remained seizure-free and their 24-hour ambulatory EEG burst-free. Our findings suggest that optimization of treatment in COAE, aimed at achieving an electroclinical and electrographic seizure-free state, may identify patients in whom therapy can be successfully ended much sooner than has been usual. Thus the same good prognosis may be reached in a shorter period of treatment with minimal risk of recurrence of absence seizures.

Anticonvulsants↗
PubMed1993

Ictal midline epileptiform discharges.

Epileptiform discharges arising from the midline (Fz, Cz, Pz) are relatively uncommon. They have been found more frequently in children, are often activated by sleep, and correlate well with clinical seizures. Only a few studies discuss the issue of midline spikes, and all of them deal with interictal activity. We report 8 patients (age range 5 weeks to 17 years) in whom ictal midline discharges were recorded from scalp EEG. The following clinical seizures were recorded: complex partial, simple sensory and myoclonic. The ictal EEG showed spike and spike and slow wave complexes, rhythmic theta, background attenuation, and paroxysmal fast activity. Based on reports of animal experiments and on the variety of types of clinical seizures and their ictal EEG correlates in the patients reported here, it is suggested that the midline scalp EEG discharges do not represent the anatomical focus of origin of the seizures. They probably reflect secondary extension and summation of a remote source of epileptogenic activity.

Adolescent↗
PubMed1992

Fatal familial infantile glycogen storage disease: multisystem phosphofructokinase deficiency.

An infant girl of consanguinous Bedouin parents suffered from fatal early onset of progressive generalized muscle weakness. Her older brother suffered from similar weakness and cardiomyopathy, which led to his death at the age of 21 months. A muscle biopsy performed on the propositus at the age of 9 months was PAS-negative, and showed nonspecific myopathic changes. A second muscle biopsy, performed at 21 months of age, a few days before her death, and postmortem study of heart and liver, disclosed excessive extralysosomal glycogen storage and reduced phosphofructokinase-1 (PFK-1) activity. Because the genes encoded for PFK-1 in liver and muscle are located on separate chromosomes, the reduced enzyme activity in both tissues could not be related to a single mutation for this enzyme. Activity of 6-phosphofructose-2-kinase (PFK-2), a recently discovered physiological activator to all PFK-1 isozymes, was normal in the liver. The possibility that this multisystem PFK-1 deficiency may be related to the absence of a yet unknown activator, common to all PFK-1 isozymes, is discussed.

Biopsy↗
PubMed1992

Acute severe combined demyelination.

We present a second case in which Guillain-Barré syndrome (GBS) and acute disseminated encephalomyelitis (ADEM) appeared simultaneously, both in acute and fulminant form. The patient, a 10-year-old girl, presented with acute onset of coma and flaccid, are-flexic quadriparesis. The elevated CSF protein levels and delayed F waves fulfilled the criteria of GBS and an MRI study revealed extensive multifocal demyelination compatible with a diagnosis of ADEM. Prompt clinical response followed by complete recovery was achieved by treatment with corticosteroids. It is suggested that acute severe combined demyelination might constitute a separate entity in which the demyelinating process, involving simultaneously the central and the peripheral nervous systems, indicates immune response against a component of the myelin of one system carrying cross-antigenicity with the other.

Acute Disease↗
PubMed1992

Detection of herpes simplex virus in gingival tissue.

The presence of herpes simplex virus (HSV) antigens was shown by immunofluorescence staining in 26 of 66 (39.3%) specimens of clinically healthy gingiva, but only one sample contained infectious virus. HSV DNA sequences were clearly identified in intact gingival cells by dot blot hybridization in one specimen, and a weak pattern in a second one. Both specimens harbored viral antigens. These findings of viral genome and protein expression suggest that the virus is present in the latent form in the gingiva.

Adult↗
PubMed1990

CT in glutaric aciduria.

Explore the source record for details and available documents.

Amino Acid Metabolism, Inborn Errors↗
PubMed1989

Propionic acidemia--biochemical studies.

The first documented case of propionic acidemia in Israel is described. Diagnosis was based on three independent methods: analysis of urinary organic acids by gas chromatography/mass spectrometry, assay of propionyl CoA carboxylase activity and oxidation of 1-14C-propionate by cultured skin fibroblasts. The use of more than one method for confirmation of the diagnosis is considered to be of importance in providing an additional margin of safety in cases where genetic counseling and prenatal diagnosis in future pregnancies are indicated.

Ammonia↗
PubMed1988

Acute confusional state in childhood.

Acute confusional state (ACS) relates to a sudden alteration of the mental status. The impairment may be global or confined to a specific faculty of higher cortical function. Such specificity does not depend on the nature of the pathological process, but rather on the anatomical location of the area of the brain which is involved. In the absence of relevant medical history and associated signs and symptoms, the differential diagnosis of ACS may be difficult. Two case reports of unusual causes of ACS are presented: basilar migraine manifesting as transient global amnesia, and absence status. These are followed by a brief review of etiological causes of ACS commonly encountered in the pediatric practice, and a more detailed review of rare causes, such as non-convulsive epilepsy and migraine. A list of auxiliary tests for cases which are not readily diagnosed is presented.

Acute Disease↗
PubMed1987

Familial juvenile onset of Bell's palsy.

Familial Bell's palsy is uncommon and its genetic pattern is not well established. In this report, four female members of one family, the patient, her mother, the maternal aunt, and the maternal grandmother, with Bell's palsy are described. In three, the onset was juvenile at the age of 12. The possibility is raised that hormonal metabolic changes of puberty when associated with genetic predisposition may play a role in causing Bell's palsy.

Adolescent↗
PubMed1987

Benign focal epilepsy of childhood: individual and intrafamilial multifocality of spikes.

Benign focal epilepsy of childhood (BFEC) is a familial, age specific, primary seizure disorder with both clinical and electroencephalographic focal characteristic features. The mental capacity remains intact, and no related neurological deficit is known. The seizures are easily amenable to treatment. BFEC is most commonly associated with central-midtemporal spikes. In some patients occipital spikes may be found. We report three patients with BFEC and present their corresponding EEG recordings. The first, a female age 10, had a history of a single grand mal seizure. Her EEG showed simultaneous firing of two independent foci, occipital and central-midtemporal. The second, a 10-year-old boy who was evaluated for headache, had typical central-midtemporal spikes. His 8-year-old asymptomatic sister's EEG showed benign occipital-temporal spikes.

Child↗