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Biomedical subjects

A Lorber

Publications and source records attributed to A Lorber.

At least 19 recordsLinked to original sources
PubMed2005

Determination of 234U/238U ratio: comparison of multi-collector ICPMS and ICP-QMS for water, hair and nails samples, and comparison with alpha-spectrometry for water samples.

The (234)U/(238)U ratio in water, hair and nails samples was determined by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) and by alpha-spectrometry for the water samples only. A correlation of 0.99 was found between the two ICPMS methods and of 0.98 with alpha-spectrometry. The range of activity ratios was between 0.9 and 2.6 according to the MC-ICPMS measurements. The reproducibility of both ICPMS techniques was better than 4% for water samples containing 1 mug l(-1) of uranium and a (234)U/(238)U atom ratio of 54.9 x 10(-6). Sample preparation for the ICPMS consisted of dilution of water samples containing >10 microg l(-1) of uranium and measurement time was approximately 1 min, while alpha-spectrometry involved pre-concentration and separation of the uranium and counting times of 1,000 min.

Body Burden↗
PubMed2005

Urine, hair, and nails as indicators for ingestion of uranium in drinking water.

The concentration of uranium in urine, hair, and nails due to continuous exposure through ingestion of drinking water was studied. The study population consisted of 205 individuals living in 134 different households in southern Finland where drinking water is supplied from private drilled wells. The population was selected to include a broad range of uranium daily intake from drinking water (0.03-2,775 microg d). The uranium content in drinking water, urine (overnight collection), hair and nails was determined by ICPMS. Uranium in urine was corrected for the matrix effects by use of thallium as an internal standard and adjusted by creatinine normalization. Hair and toenail samples were rinsed to remove external contamination prior to acid digestion and analysis. The uranium content in all excretion pathways was correlated with the uranium intake, particularly at elevated levels (> or =10 microg d) where drinking water was the major source of exposure to uranium. The median of the individual uranium absorption factors for urine, hair, and toenails were fu=0.003, fh=0.003, and fn=4 x 10, respectively. The association between the different bioassays was examined. The absorption factor, f1, was calculated for the population with an intake above 10 microg d and was below 0.01 for 72% of the study persons (range 0.0002 to 0.070). No statistically significant difference in f1 values was found between women and men. However, the absorption factor was higher among younger (< 60 y) than older (> or =60 y) subjects and among people with a lower exposure (below 100 microg d) than among those that ingest over 100 microg d.

Administration, Oral↗
PubMed2005

Measurement of the 234U/238U ratio by MC-ICPMS in drinking water, hair, nails, and urine as an indicator of uranium exposure source.

The isotopic ratio (234)U/(238)U in drinking water and in hair, toenail, and urine samples from 45 individuals who consumed 0.2-2775 microg d(-1) of uranium in their drinking water was determined using a multi-collector inductively coupled plasma mass spectrometer (MC-ICPMS). The U/U atom ratio in the water samples varied from 51 x 10(-6) to 252 x 10(-6) whereas in secular equilibrium (i.e., unity activity ratio) the ratio is 54.9 x 10(-6). The correlation of the (234)U/(238)U ratio between hair and nail samples was 0.98, and between hair and nails and urine the ratio was 0.91 and 0.89, respectively. The correlation of the ratio between water and the hair or nails was 0.97 but only 0.72 for water and urine, possibly due to spectral interferences. These results conclusively demonstrated that the uranium found in the bioassays can be traced to the drinking water, thus providing a direct link to the source of exposure. Hair may serve as an excellent indicator of occupational or environmental exposure to uranium and provide information regarding its source. Bioassay of hair is attractive as it is an effective bio-concentrator, samples can be easily stored, the concentration reflects an integrated value, and, finally, the measurement of the (234)U/(238)U isotopic ratio in digested hair samples by MC-ICPMS is feasible and highly informative. Hair bioassay can also be used to assess exposure to depleted uranium long after the subjects have left the area suspected of contamination.

Body Burden↗
PubMed2004

Right ventricular diastolic dysfunction and patent foramen ovale causing profound cyanosis.

A 73 year old woman presented with profound central cyanosis and a history of a minor stroke. She had normal heart morphology, normal pulmonary artery pressure, and a normal coronary angiography. A patent foramen ovale (PFO) with a massive right to left shunt was demonstrated at the atrial level, with normal pulmonary venous saturations and PO2 values. This rare, age related case of right ventricular diastolic dysfunction in a normotensive patient revealed a generous PFO allowing a pronounced right to left shunt.

Aged↗
PubMed2001

A missense mutation in a highly conserved region of CASQ2 is associated with autosomal recessive catecholamine-induced polymorphic ventricular tachycardia in Bedouin families from Israel.

Catecholamine-induced polymorphic ventricular tachycardia (PVT) is characterized by episodes of syncope, seizures, or sudden death, in response to physical activity or emotional stress. Two modes of inheritance have been described: autosomal dominant and autosomal recessive. Mutations in the ryanodine receptor 2 gene (RYR2), which encodes a cardiac sarcoplasmic reticulum (SR) Ca(2+)-release channel, were recently shown to cause the autosomal dominant form of the disease. In the present report, we describe a missense mutation in a highly conserved region of the calsequestrin 2 gene (CASQ2) as the potential cause of the autosomal recessive form. The CASQ2 protein serves as the major Ca(2+) reservoir within the SR of cardiac myocytes and is part of a protein complex that contains the ryanodine receptor. The mutation, which is in full segregation in seven Bedouin families affected by the disorder, converts a negatively charged aspartic acid into a positively charged histidine, in a highly negatively charged domain, and is likely to exert its deleterious effect by disrupting Ca(2+) binding.

Age of Onset↗
PubMed2001

Autosomal recessive catecholamine- or exercise-induced polymorphic ventricular tachycardia: clinical features and assignment of the disease gene to chromosome 1p13-21.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (PVT) is characterized by episodes of syncope, seizures, or sudden death in response to physiological or emotional stress. In 2 families with autosomal dominant inheritance, the disease gene was mapped to chromosome 1q42-43. The objectives of this study were to characterize the clinical features of the disease in a Bedouin tribe from Israel and to map the disease gene. METHODS AND RESULTS: In this Bedouin tribe, 9 children (age, 7+/-4 years) from 7 related families have died suddenly during the past decade, and 12 other children suffered from recurrent syncope and seizures starting at the age of 6+/-3 years. Parents of affected individuals were asymptomatic and were all related (first-, second-, or third-degree cousins). Segregation analysis suggested autosomal recessive inheritance. All 12 symptomatic patients and 1 asymptomatic sibling (mean age, 13+/-7 years) were found to have a relative resting bradycardia (64+/-13 bpm, versus 93+/-12 bpm in the unaffected siblings), as well as PVT induced by treadmill or isoproterenol infusion and appearing at a mean sinus rate of 110+/-10 bpm. Patients responded favorably to treatment with beta-blockers. A genome-wide search using polymorphic DNA markers mapped the disease locus to a 16-megabase interval on chromosome 1p13-21. A maximal lod score of 8.24 was obtained with D1S189 at theta=0.00. Sequencing of KCND3, a gene that encodes an I(tO) potassium channel transporter, did not reveal any significant sequence alterations. CONCLUSIONS: This unique form of autosomal recessive PVT affects young children and may be lethal if left untreated. Linkage analysis maps this disorder to chromosome 1p13-21.

Adolescent↗
PubMed2001

[Long-term sequelae of malignant tumors in childhood: consequences of late side-effects].

110 children with malignant diseases (leukemia excepted) who survived 5-20 years (median 9) post-therapy were followed (1996-1998). Median age during follow-up was 15 years (range 5-23). The most common malignancies were brain tumors, lymphoma, retinoblastoma and Wilm's tumor. The 174 late side-effects included endocrine disorders (19%), cognitive impairment (14%), orthopedic dysfunction (12%), alopecia (12%), dental damage (11%), psychological (8%) and neurological (8%) disturbances, and azoospermia or amenorrhea (5%). There was no cardiac or renal damage and no second malignancy. 29% of side-effects were severe. There was significant reduction in quality of life in 54 (49%), in 27 of whom it was severe enough to require psychological intervention. Treatment of brain tumor caused 98 late side-effects in 28 patients (sequelae-to-patient ratio [SPR] 3.3). Most cognitive, endocrine and neurological disorders, and most cases of alopecia, dental and psychological difficulties were in these patients. There were frequent late complications in those treated for retinoblastoma (SPR 1.8), and bone or soft tissue sarcomas (SPR 0.8). Those treated for Wilm's tumor had few side-effects (SPR 0.4). Late side effects were most frequent after radiation, reaching as high as SPR 2.4. It averaged only 0.5 in those treated with chemotherapy alone or in combination with surgery. Reduction of late side-effects in these patients requires using less toxic modalities, as long as cure rate is not compromised. When considering secondary strategies, screening for early detection of late complications would enable immediate solutions, such as hormonal replacement or providing compensating skills for post-treatment disability.

Adolescent↗
PubMed2000

NPS 1506: a novel NMDA receptor antagonist: neuroprotective effects in a model of closed head trauma in rats.

We examined whether NPS 1506, a novel uncompetitive N-methyl-D-aspartate receptor antagonist, influences neurological outcome following closed head trauma (CHT) in rats. One hundred ten rats were divided into 11 groups: CHT (yes/no), treatment with NPS 1506 (yes/no), and time of euthanization (24 h/48 h). The dose of NPS 1506 was 1 mg/kg IV at 1 and 4 hours following CHT or sham operation. Closed head trauma induced the following changes in the injured hemisphere: Decreased specific gravity (sg) (1.036 +/- 0.006) and magnesium (Mg) (0.042 +/- 0.005 microg/mg) at 24 hours, and potassium (K) at 24 (1.145 +/- 0.376 microg/mg) and 48 hours, and increased water content (W) (84.9 +/- 2.5%) and sodium (Na) (2.135 +/- 0.699 microg/mg) at 24 hours, and calcium (Ca) at 24 (0.543 +/- 0.157 microg/mg) and 48 hours. These were reversed by NPS 1506; sg of 1.043 +/- 0.004, Mg of 0.077 +/- 0.009 microg/mg, K of 1.930 +/- 0.238 microg/mg, W of 81.5 +/- 1.9%, Ca of 0.043 +/- 0.023 microg/mg, and Na of 0.688 +/- 0.110 microg/mg. In groups not given NPS 1506, a nonsignificant decrease in neurological severity score (NSS) occurred at 24 and 48 hours as compared to NSS at 1 hour after CHT. In groups given NPS 1506, NSS at 24 and 48 hours decreased significantly (improved) compared to NSS at 1 hour, but not compared to NSS at 24 and 48 hours in groups not given NPS 1506. NPS 1506 caused no significant change in ischemic tissue volume or hemorrhagic necrosis volume in the injured hemisphere at 24 hours or 48 hours. These findings indicate that NPS 1506 improved measures of brain tissue edema (at 24 hours but not at 48 hours) and ion homeostasis, and this improvement was not related to other measures of outcome.

Animals↗
PubMed2000

The Ross operation: initial Israeli experience.

BACKGROUND: The need for aortic valve replacement in children and young adults poses a special problem to cardiologists and surgeons. Replacing the sick aortic valve with the patient's pulmonary valve as described by Ross has proven to be a good option in this special age group. OBJECTIVE: To review our initial experience in order to assess the short-term results. METHODS: From January 1996 to June 1999, 40 patients (age 8 months to 41 years) underwent aortic valve replacement with pulmonary autograft. Indications for surgery were congenital aortic valve disease in 30 patients, bacterial endocarditis in 5, rheumatic fever in 3, and complex left ventricular outflow tract obstruction in 3. Trans-esophageal echocardiography was performed preoperatively and post-bypass in all patients, and transthoracic echocardiography was done prior to discharge and on follow-up. RESULTS: There was no preoperative or late mortality. All patients remain in functional class I (New York Heart Association) and are free of complications and medication. None showed progression of autograft insufficiency or LVOT obstruction. Homograft insufficiency in the pulmonary position has progressed from mild to moderate in one patient, and three developed mild homograft stenosis. CONCLUSIONS: The Ross procedure can be performed with good results in the young population and is considered an elegant surgical alternative to prosthetic values and homografts.

Adolescent↗
PubMed1998

[Familial occurrence of Ebstein anomaly].

Ebstein anomaly is a rare congenital disease which affects location, structure and mobility of the tricuspid valve, and right atrium and ventricle. Although most cases are sporadic, familial occurrence has been reported. We report 2 brothers born with Ebstein anomaly. The parents were first degree cousins and there were 8 other children. 2 daughters were born with other congenital heart anomalies, 1 with ventricular septal defect and the other with severe pulmonary artery stenosis. We suggest that in some families, Ebstein anomaly is an autosomal dominant disease with different expression in the sexes.

Adolescent↗
PubMed1998

Coexistence of acquired protein S and protein C deficiency and the Arg506Gln mutation in factor Va in a child with severe thromboembolic disease.

An 11-y-old girl who presented with cellulitis and clinical signs of deep vein thrombosis (DVT) is reported here. She developed staphylococcal sepsis, recurrent septic emboli and a large vegetation on the tricuspid valve. The patient was found to be heterozygous for the Arg506Gln mutation in factor Va and had low levels of protein C and protein S during the sepsis. The coexistence of the two thrombophilic states may explain the severe thromboembolic manifestations.

Alleles↗
PubMed1998

Uranium in urine--normalization to creatinine.

"Spot samples" of urine are routinely used to monitor occupational exposure to uranium and other toxic heavy metals, such as mercury, lead, and cadmium. In the present work, it was shown that diurnal variations in the uranium concentration in different urine samples from the same individual could be quite large. However, these variations were in correlation to the creatinine level of the same samples, with values of R = 0.72-0.99, for the five subjects studied here. Thus, it is proposed here that uranium concentrations in "spot" urine samples be expressed in terms of ng uranium g(-1) creatinine rather than ng uranium L(-1). Once the 24-h creatinine level is estimated for the individual based on weight, height and age, the adjusted values can be used for determination of the internal dose of uranium.

Circadian Rhythm↗