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PubMed1976

[External quality control measures for blood lead analysis of persons living in a high lead exposure area (author's transl)].

Analytical laboratories engaged in studies regarding the exposure of larger population groups to lead should--for the sake of better intercomparability of data--subject themselves to internal and external quality control. In this paper an example of external quality control for blood lead, ALA-D and FEP analysis by 3 institutes is given. Evaluation by correlation analysis showed satisfactory results for all 3 parameters studied. Apart from discussing the results, suggestions are made regarding conduction of realistic quality control measures for the 3 lead-dependent biological exposure parameters.

Adult↗
PubMed1991

[A case of lead neuropathy--importance of subclinical entrapment of nerves in lead neuropathy].

The patient was a left handed 25-year-old man who had worked in a vinyl chloride resin factory since July 1987 using lead stearate as a stabilizer. During the two years preceding hospitalization, he had been admitted three times for colicky abdominal pain with constipation and nausea. Anemia and proteinuria without causative diseases were pointed out. Because of progressive muscle weakness of hands which began since January 1989, he was admitted to our neurologic clinic on October 2 1989. Neurological examination showed severe atrophy of both small hand muscles without sensory disturbances. Left hand was predominantly affected, especially in interossei muscles. Laboratory findings are as follows; RBC 3.25 million/cu.mm: Hb 9.7 g/dl:blood lead concentration 100 micrograms/dl: urinary coproporphyrin 4503 micrograms/l: urinary delta-ALA 138 mg/l: and urinary lead excretion after 1 g CaEDTA infusion: 3938 micrograms/day. Electromyography of extensor carpi radialis, flexor carpi ulnaris and opponens showed increased polyphasic, long duration MUPs. Electromyography of dorsal interossei showed fibrillation. Nerve conduction study showed mildly decreased motor and sensory conduction velocities and markedly reduced amplitude of compound muscle action potentials (CAMPs). Investigation by inching method revealed conduction block of left ulnar nerve across elbow. After CaEDTA chelating therapy, 1 g once a week, steady improvement of muscular weakness was observed within a few months. Serial nerve condition studies revealed constant recovery of nerve conduction velocities, amplitude of CMAPs and diminution of conduction block across the left elbow. Conduction block across left elbow without sensory disturbances implies that subclinical cubital tunnel syndrome might have existed in this patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Residential deleading: effects on the blood lead levels of lead-poisoned children.

Acute elevations of venous blood lead levels (PbB) are periodically reported in children with chronic lead poisoning, during deleading of their houses. To evaluate this phenomenon 114 preschool children who entered the Massachusetts Childhood Lead Poisoning Prevention Program case management system during 1984 and 1985 were retrospectively studied. PbB increased from a mean (+/- SE) of 1.76 +/- 0.03 mumol/L (36.4 +/- 0.6 micrograms/dL) prior to deleading to 2.03 +/- 0.07 mumol/L (42.1 +/- 1.5 micrograms/dL) during deleading (P less than .001). Among 41 subjects for whom deleading was done by dry scraping and sanding, the mean mid-deleading PbB was higher than the pre-deleading PbB by 0.44 +/- 0.12 mumol/L (9.1 +/- 2.4 micrograms/dL). However, when deleading was done by covering or replacement of painted surfaces in the residences of 12 subjects, mid-deleading PbB decreased 0.11 +/- 0.12 mumol/L (2.25 +/- 2.4 micrograms/dL) (P less than .005). In a subset of 59 subjects who had no chelation therapy and were available for follow-up 250 +/- 14 days after completion of deleading, PbB had decreased from 1.72 +/- 0.04 mumol/L (35.7 +/- 0.9 micrograms/dL) to 1.24 +/- 0.04 mumol/L (25.5 +/- 0.9 micrograms/dL) (P less than .001). The long-term effect of deleading is a significant reduction in PbB. However, deleading resulted in a significant, albeit transient, increase in PbB.

Age Factors↗
PubMedDate not supplied

[Comparative study of blood lead and urine alanine in workers exposed to high concentrations of environmental lead].

The increase of the levels of lead in the blood and ALA in the urine in 40 workers whose jobs entail their coming into contact with lead salts has been studied over a four-year period, it having been observed that although the level of lead found in the blood varied in a majority of cases, it has been found to be approximately 30 micrograms per 100 ml, the ALA in the urine ranging around 0.40 mg per 100 ml. When these same workers were given medical checkups, no significant variations were found with regard to the type of work in which they were involved.

Air Pollutants, Occupational↗
PubMed1988

Effect of dietary lead intake on lead retention in adult rats.

132 female rats with a live weight of 177 to 224 g were provided over a period of 17 days a half-synthetic diet with a lead concentration of 0.4 mg/kg. Then 120 of the animals were divided into 15 treatment groups fed with a diet different in Pb content (0.02, 0.04, 0.08, 0.12, 0.22, 0.42, 0.62, 0.82, 1, 5, 10, 50, 100, 400 and 800 mg Pb2+ per kg) over a period of 29 days. The feed was rationed so as to provide the minimum energy maintenance requirement. Pb retention dependent on different lead supplies was determined by subtracting the Pb contents of carcasses of 12 reference animals sacrificed at the beginning of the experiment from the Pb content of carcasses of rats at the end of the experiment. Up to a Pb concentration of 0.42 mg/kg in the diet Pb retention fluctuated around zero. Then the retention was slightly positive up to 5 mg/kg Pb in the diet. Up to 10 mg/kg Pb in the diet Pb retention increased sharply. Concentrations of iron, copper, zinc, and manganese in carcasses were affected only slightly by the varying concentration of lead in the diet.

Animals↗
PubMed1988

Localization of lead in the kidney and liver of rats treated in vivo with lead acetate: ultrastructural studies on unstained sections.

The subcellular distribution and ultrastructural effects of lead have been studied in the kidneys and liver of rats given lead acetate (600 ppm Pb2+) in their drinking water for 6 months. Control rats were given sodium acetate. Tissue samples were fixed in glutaraldehyde and examined by electron microscopy with and without staining. Unstained sections of both kidney and liver from lead-treated animals showed small particles (2-5 nm diameter) of very high electron density which appear to represent a deposited form of Pb2+. Ultrastructural changes in the kidneys were largely confined to glomeruli (swelling of endothelial cells, fusion of foot processes, thickening of basement membrane) and proximal tubules (ranging from minimal sub-lethal changes to necrotic disorganization). The electron-dense particles of Pb2+ occurred in large clusters in basement membranes. As individual particles, or small groups, they were numerous in nuclei of proximal epithelium but usually only a few, largely confined to vesicles or inclusion bodies, were present in the cytoplasm. Only when cells were markedly damaged morphologically were particles more generally distributed in the cytoplasm. Liver damage by Pb2+ was largely confined to centrilobular regions. Endothelial and Kupffer cells were the most affected; they often sequestered large numbers of the particles. In parenchymal cells, particles were few and mainly in vesicles, but they were more widely distributed in the cytoplasm when morphological injury was apparent. The free distribution of Pb2+ in liver and kidney seems to be limited by its deposition in basement membranes and sequestration in reticulo-endothelial cells; intracellular distribution in healthy cells is also limited, by deposition in nuclei (in kidney only) or cytoplasmic vesicles.

Animals↗
PubMed1995

Neurotoxicity in rats chronically exposed to lead ingestion: measurement of intracellular concentrations of free calcium and lead ions in resting or depolarized brain slices.

The intracellular free calcium (Ca2+) or lead (Pbi2+) ions were measured by using 19F-NMR and 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid in brain slices obtained from control rats and rats chronically exposed to 1 mg/kg.day or 100 mg/kg.day dose of Pb acetate ingestion. The basal Cai2+ values obtained in this study were comparable to the values reported previously for brain neurons by using the Fura-2 method (Singh, 1993a). The concentrations of total Pb in blood samples obtained from 2-week old rats exposed to 1 and 100 mg/kg.day doses of lead acetate were 31 and 521 micrograms/dl respectively. The concentrations of total Pb in brain samples obtained from 2-week old rats exposed to 1 and 100 mg/kg.day doses of lead acetate were 150 and 2700 ng/g respectively. The concentration of Pb in neonatal and adult samples did not differ significantly. Free Pb2+ was not detected in samples obtained from the rats exposed to a Pb dose of 1 mg/kg.day; however, a small concentration (ranging from 100 to 300 pM) of the ion was detected in samples obtained from the rats exposed to a Pb dose of 100 mg/kg.day. This suggests that either a small proportion of total Pb is ionized in brain or there is an efflux of Pb2+ from intracellular fluid into the incubation medium. Depolarization caused significant increase in Cai2+ in cortical slices obtained both from control and Pb-exposed rats. However, depolarization increased Pbi2+ only in samples obtained from rats exposed to a Pb dose of 100 mg/kg.day.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Lead poisoning from lead-soldered electric kettles.

Lead poisoning occurred in two infants, causing lead encephalopathy in one but no symptoms in the other. Both infants had been fed a formula prepared with water boiled in a lead-soldered electric kettle. The diagnosis was suggested by dense metaphyseal bands in radiographs, illustrating the importance of careful examination of "routine" radiographs, particularly in asymptomatic infants.

Bone and Bones↗
PubMed1981

Specificity of porcine liver gal beta (1 leads to 3)galnac-r alpha(2 leads to 3) sialyltransferase sialylation of mucin-type acceptors and ganglioside GM1 in vitro.

Porcine liver microsomes are capable of transferring sialic acid from CMP-NeuAc to [14C]galactosylated ovine submaxillary asialo-mucin, porcine submaxillary asialo/afuco-mucin and ganglioside GM1. The specificity of the porcine liver sialyltransferase (CMP-N-acetylneuraminate: D-galactosyl-glycoprotein N-acetylneuraminyltransferase, EC 2.4.99.1) towards the first acceptor, [14C]Gal-GalNAc-protein, was investigated by means of methylation studies on the oligosaccharides changes cleft-off from the sialylated product glycoprotein by beta-elimination under reductive conditions. It appeared that sialic acid was transferred solely to position C-3 of galactose residues on Gal beta(1 leads to 3)GalNAc disaccharide units. Transfer to GalNAc residues was completely absent. Competition experiments and heat activation studies suggested that the same enzyme also converts ganglioside GM1 to ganglioside GD1a. Therefore, this porcine liver sialyltransferase can be designated as a Gal beta(1 leads to 3)GalNAc-R alpha(2 leads to 3) sialyltransferase.

Acetylgalactosamine↗
PubMed1998

Usefulness of ST-segment elevation in lead III exceeding that of lead II for identifying the location of the totally occluded coronary artery in inferior wall myocardial infarction.

The presence of ST-segment elevation in lead III exceeding that of lead II, particularly if combined with ST elevation in lead V1, proved to be a powerful marker for occlusion of the proximal or midportion of the right coronary artery. These findings helped to determine the extent of myocardium at risk in inferior wall myocardial infarction and may further guide the decision to administer thrombolytics.

Algorithms↗
PubMed1983

Clinical evaluation of a sutureless cardiac pacing lead: chronic threshold changes and lead durability.

Chronic threshold changes and durability of the Medtronic 6917 sutureless cardiac pacing lead were evaluated in 100 consecutive patients. A bipolar pacing system was established in each patient. Lead failure occurred in 4 patients; all failures resulted from exit block or loss of adequate contact between electrode and myocardium. Electrode fracture or loss of lead insulation was not observed. Fifty patients had replacement of the pulse generator 27.4 +/- 1.8 months after implantation. Long-term stimulation threshold voltage was about 2.5 times greater and current was about 3.5 times greater than values obtained at initial implantation, yet they continued to permit safe and effective cardiac pacing.

Adolescent↗
PubMed1995

Reconstruction of the standard 12-lead ECG from recordings using nonstandard activity-compatible proximal limb lead positions.

Proximal or torso placement of limb leads in the 12-lead electrocardiogram (ECG) has been shown to influence the appearance of QRS waveforms considerably. A method was developed for computer-based reconstruction of standard-like waveforms from nonstandard torso-recorded waveforms. Reconstruction coefficients required by the method were determined using ECG data obtained from 30 patients. The coefficients were then applied on an independent test set of 100 patients. In 21 of these patients, a second standard EGG was obtained the next day to determine the day-to-day variation in QRS waveforms. R wave amplitudes in leads I and II, and electrical axes in the frontal plane were measured in the standard ECG, the nonstandard ECG, and the reconstructed ECG. It is shown that the reconstruction method yields ECGs that differ less from standard than do two standard ECGs recorded on consecutive days. The performance of the reconstruction method was not influenced by age, sex, height, or weight.

Adult↗
PubMed1978

Delineation of syndromes due to partial 6q imbalances. Trisomy 6q21 leads to qter and monosomy 6q221 leads to qter in two unrelated patients.

Two unrelated patients carrying imbalances involving the long arm of chromosome 6 are described. In the first trisomy 6q21 leads to qter had segregated from a maternal translocation t(6;16)(q15;q24). The clinical data of the proposita are compared with those of three other published cases. A partial 6q trisomy syndrome is postulated characterized by: growth deficiency of prenatal onset, psychomotor retardation, craniofacial abnormalities (microcephalia, hypertelorism, downward slanting palpebral fissures, flattened nasal bridge, long philtrum, hypoplastic perioral features, large jaw resulting in a round appearance of the face, receding chin, malformed ears) and dysmorphic extremities (contractures of limbs due to short flexor tendons, hypoplastic fingers, toes and nails). In the second case, monosomy 6q221 leads to qter resulted from a de novo rearrangement and was responsible for mental retardation and facial dysmorphism (reduced biparietal diameter, hypotelorism, absent eyebrows, prominent nose, ptosis, receding chin, dysmorphic ears). Studies of HLA and PGM3 segregation showed normal inheritance patterns and ruled out the location of these genes in bands 6q221 leads to qter.

Abnormalities, Multiple↗
PubMed2002

Attentional modification of short-lead prepulse inhibition and long-lead prepulse facilitation of acoustic startle among preadolescent boys.

In adults, short-lead prepulse inhibition and long-lead prepulse facilitation of startle are greater during attended than ignored prestimuli. To examine these phenomena in children, fourteen 9- to 12-year-old boys completed a tone discrimination task in two sessions separated by 1 week. During each tone series, participants attended to one pitch and ignored the other. Startle probes (102 dB) were presented 120, 240, 2,000 or 4,500 ms following the onset of two-thirds of tones, and during one-third of intertrial intervals. Eyeblink EMG startle was recorded. Percent prepulse inhibition at 120 ms was greater for attended than ignored stimuli in Session 1 but not Session 2. Long-lead prepulse facilitation was marginally greater for attended than ignored tones and did not vary across sessions. Test-retest reliability was moderate during attended prestimuli but was modest during ignored prestimuli. Reliability of attentional modification was poorest at 120 ms and strongest at 4,500 ms. Overall, this study extended prior work in adults and provided a basis for further study of controlled attentional modification of startle in children.

Acoustic Stimulation↗
PubMed2003

Autocapture enhancements: unipolar and bipolar lead compatibility and bipolar pacing capability on bipolar leads.

Beat-by-beat Autocapture maximizes device longevity by minimizing stimulus amplitude while assuring patient safety. Currently, Autocapture permits use of only bipolar leads. The authors have devised a detection method that operates with unipolar and bipolar leads and covers all pacing and sensing combinations (but bipolar pace and sense simultaneously). This new detection method for unipolar sensing uses the integral of the negative portion of the unipolar evoked response as a robust capture detection feature. When using bipolar leads, the method provides the flexibility of bipolar or unipolar pacing. In this study, unipolar ventricular intracardiac electrograms (EGMs) were recorded in 71 patients, 73.7 +/- 9.9 years of age; 9 with high polarization, 62 with low polarization. High polarization had polished platinum or activated carbon electrodes. Low polarization had TiN, platinized platinum, or IrOx electrodes. The intracardiac EGMs were recorded 544 +/- 796 days after implant. The pacemakers performed an automatic capture threshold test while the intracardiac EGM signals were recorded in a programmer. These digitized signals were saved for off-line analysis. The unipolar evoked response was calculated at up to six (depending on capture threshold) pacing voltages and the polarization integral at 4.5 V and at loss of capture. An automatic calibration algorithm determined if the signal-to-noise ratio was adequate for Autocapture operation. Autocapture was possible with 60 of 62 of the low polarizations, and with 6 of 9 of the high polarizations. The average values form the data collected were: average unipolar evoked response--4.1 +/- 2.1 mV, average peak negative voltage--10.0 +/- 3.7 mV, average polarization 0.3 +/- 0.34 mV, and average signal-to-noise ratio (unipolar evoked response/ polarization) 38 +/- 71. In all cases the algorithm correctly determined the appropriateness of using Autocapture with the electrodes tested and the unipolar evoked response threshold to be used.

Aged↗
PubMed2003

Utility and safety of prolonged temporary transvenous pacing using an active-fixation lead: comparison with a conventional lead.

Transvenous temporary pacing is associated with a substantial dislocation rate reported to range from 10 to 37%. The aim of the study was to assess the safety and utility of a recently introduced 3.5 Fr temporary pacing lead using active fixation in a consecutive series of 36 patients with prolonged (> or = 48 hours) transvenous temporary pacing (validation group). A group of 36 patients with prolonged transvenous pacing managed with a passive-fixation lead just prior to the introduction of the active-fixation lead served as a control group (reference group). Pacing related adverse events included dislocation, inappropriate pacing (i.e., two-fold or greater increase of initial pacing threshold), local infection, and thrombosis. There were no significant differences in patient characteristics or duration of pacing (5.84 +/- 2.4 days in the reference group vs 5.94 +/- 2.6 days in the validation group). Acute pacing threshold was significantly higher in the validation group as compared to the reference group (1.38 +/- 0.67 V vs. 0.7 +/- 0.21 V, P < 0.01). The dislocation rate was significantly lower in the validation group as compared to the reference group (5.5 vs 33.3%, P < 0.001). There were 11 (31%) pacing related adverse events in the validation group versus 21 (58%) in the reference group (P < 0.01). The vast majority of patients in the validation group (75%) had ambulatory temporary pacing. Thus, transvenous temporary pacing using active fixation is safe and is associated with a low dislocation rate and a reduction in pacing related adverse events.

Aged↗
PubMed2001

Stimulation of the left ventricle through the coronary sinus with a newly developed 'over the wire' lead system--early experiences with lead handling and positioning.

AIMS: This report describes the initial clinical results with a newly designed guiding catheter and an 'over the wire' pacing lead based on angiolasty technology to stimulate the left ventricle using the transvenous route via the coronary sinus (OTW-CV lead). METHODS AND RESULTS: In 75% of the 15 patients (6 males, 9 females, mean age of 53 +/- 9 years) with congestive heart failure, access to coronary sinus required less than 2 min; in one patient. the attempt failed. Mean R wave amplitudes plus or minus the standard deviation, measured at apical, mid-ventricular and basal positions the anterior (11.4 +/- 9.2, 10.8 +/- 6.2, 9.3 +/- 6.3 mV) and lateral or posterior veins (10.1 +/- 10.7, 8.6 +/- 6.4, 7.7 +/- 4.3 mV) showed a trend favouring the apex without statistical significance. Pacing impedance, measured at the same sites and vein tributaries, ranged from 670 +/- 191 to 915 +/- 145 ohms. Pacing thresholds measured at apical and mid ventricular sites were significantly lower than at the base in the anterior vein 2.5 +/- 2.8 and 2.8 +/- 1.8 vs 5.6 +/- 2.7 V at 0.5 ms, P<0.001). Thresholds in the lateral/posterior veins showed a similar trend but did not reach statistical significance (3.0 +/- 1.7, 3.6 +/- 1.4 +/- 1.8 V at 0.5 ms). In patients, in whom thresholds were determined in more than one vein, the 'best' mean threshold was 1.6 +/- 0.7 V. CONCLUSION: The new 'over the wire' lead and guiding catheter system allows uncomplicated access to the coronary sinus and the depth of the coronary vein tributaries. Left ventricular sensing and pacing thresholds are acceptable for chronic use in implanted cardiac rhythm management systems.

Adult↗