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Biomedical subjects

M Levy

Publications and source records attributed to M Levy.

At least 829 records · Page 46Linked to original sources
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Separate effects of a classical conditioning procedure on respiratory pumping, swimming, and inking in Aplysia fasciata.

We examined whether swimming and inking, two defensive responses in Aplysia fasciata, are facilitated by a classical conditioning procedure that has been shown to facilitate a third defensive response, respiratory pumping. Training consisted of pairing a head shock (UCS) with a modified seawater (85%, 120%, or pH 7.0 seawater--CSs). Animals were tested by re-exposing them to the same altered seawater 1 hr after the training. For all three altered seawaters, only respiratory pumping is specifically increased by conditioning. Swimming is sensitized by shock, and inking is unaffected by training, indicating that the conditioning procedure is likely to affect a neural site that differentially controls respiratory pumping. Additional observations also indicate that the three defensive responses are differentially regulated. First, different noxious stimuli preferentially elicit different defensive responses. Second, the three defensive responses are differentially affected by shock. Inking is elicited only immediately following shock, whereas swimming and respiratory pumping are facilitated for a period of time following the shock. Third, swimming and respiratory pumping are differentially affected by noxious stimuli that are delivered in open versus closed environments. These data confirm that neural pathways exist that allow Aplysia to modulate separately each of the three defensive behaviors that were examined.

Animals↗
PubMedDate not supplied

Uncombable hair (cheveux incoiffables, pili trianguli et canaliculi) syndrome: brief review and role of scanning electron microscopy in diagnosis.

Uncombable hair syndrome was first described some 3 decades ago as "cheveux incoiffables" and is also known as spun-glass hair and pili trianguli et canaliculi. Both inherited (autosomal dominant and recessive with variable levels of penetrance) and sporadic forms of uncombable hair syndrome have been described, both being characterized by scalp hair that is impossible to comb due to the haphazard arrangement of the hair bundles. A characteristic morphologic feature of hair in this syndrome is a triangular to reniform to heart shape on cross-sections, and a groove, canal or flattening along the entire length of the hair in at least 50% of hairs examined by scanning electron microscopy. Most individuals are affected early in childhood and the hair takes on a spun-glass appearance with the hair becoming dry, curly, glossy, lighter in color, and progressively uncombable. Only the scalp hair is affected. Several conditions are associated with uncombable hair, such as ectodermal dysplasia, retinal dysplasia/pigmentary dystrophy, juvenile cataract, digit abnormalities, tooth enamel anomalies, oligodontia, and phalangoepiphyseal dysplasia. Other syndromes with hair abnormalities may also mimic uncombable hair syndrome clinically and these include, Rapp-Hodgkin ectodermal dysplasia; loose anagen hair syndrome; ectodermal dysplasia, ectrodatyly, cleft lip/palate (EEC) syndrome; and familial tricho-odonto-onchyial ectodermal dysplasia with syndactyly. Unlike other conditions with an uncombable hair component, uncombable hair syndrome alone (cheveux incoiffables, pili trianguli et canaliculi) is not associated with physical, neurologic, or mental abnormalities. In most cases of uncombable hair syndrome, the hair is grossly abnormal in infancy and early childhood, but may have improved manageability later in life. Scanning electron microscopy of hair samples provides definitive evidence for diagnosis of clinically suspected uncombable hair syndrome and eliminates other hair abnormalities from the differential diagnosis.

Chemical Phenomena↗
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[Membrano proliferative glomerulonephritis (author's transl)].

128 cases of Membrano proliferative glomerulonephritis have been divided in two groups, the first one (84 cases), with subendothelial deposits, the second one (44 cases) "with dense intramembranous deposits". Streptococcal infections more frequently precede the membranoproliferative glomerulonephritis with dense intramembranous deposits (20% and 11%). In this group there is a rapid onset and macroematuria is more frequent (36% and 18%). Nephrotic syndrome has the same frequency in the two groups (more than 80%). Because of the more frequent association "dense deposits" and crescents this group show a more frequent evolution toward renal failure (43% and 35%).

Antibody Formation↗
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Medical findings in nickel-cadmium battery workers.

Thirty-eight workers from a factory producing nickel-cadmium and other types of batteries came to us for medical evaluation. They included 21 women and 17 men (seniority 2-20 years, age range 31-63 years), and represented a self-selected subset of 700-900 ever-employed and 200+ recently or currently employed workers in the factory. Thirty-four worked on the nickel-cadmium assembly line. Symptoms and signs included: headache in 34; weakness, fatigue and lassitude in 26; dizziness in 16; pruritus and skin eruptions in 37; gingivitis, teeth loss and caries in 34; nasal congestion, nosebleeds and anosmia in 30; cough, phlegm production, wheezing and shortness of breath in 26; "asthma" in 14; bone pain in 18; urinary frequency, beta 2 microglobulinuria and kidney stones in 17; and sterility or multiple abortions (33) in 8 of 21 women. One additional patient had died from an "amyotrophic lateral sclerosis-like syndrome", while CT scans in six workers revealed brain atrophy. One other worker had leukemia, and two had died from cancer (lung and pancreas). Those who had worked for more than 10 years had more symptoms and signs than shorter-term employees, especially neurological illness, bone pain and urinary tract problems, including beta 2 microglobulinuria. Past blood and urinary cadmium levels were in the range of 1.6-8.7 micrograms/dl and 8-306 micrograms/l, respectively. Our findings indicated that: a) health risks for workers were not confined to the nickel-cadmium assembly line or to older workers, b) hazardous exposures still existed and illness appeared in new workers after a clean-up and intervention program, and c) exposures involved increased risks for renal disease and cancers. Finally, there is a need to control exposures and determine health risks in the full cohort of those ever employed, in the workers' children, and in the surrounding environment (air, ground, water) due to the dumping of waste from the plant.

Adult↗
PubMedDate not supplied

Cardiac assistance by atrial or ventricular cardiomyoplasty.

Dynamic cardiomyoplasty was conceived to enhance cardiac performance by assisting myocardial contraction. Technically, this procedure consists of placing a pedicled latissimus dorsi muscle flap around the heart and subsequent muscle electrostimulation in synchrony with ventricular systole. Three types of dynamic cardiomyoplasty can be considered. (1) Atrial or ventricular reinforcement is accomplished by wrapping the latissimus dorsi muscle flap around the heart to support hypokinetic or akinetic areas secondary to congenital or acquired diseases. The atrial reinforcement may be performed to improve atrial output after Fontan-type procedures. (2) Ventricular substitution is performed to replace a portion of the ventricular wall. Autologous pericardium is used to create a neoendocardium and facilitate hemostatic closure of the ventricle. The pedicled latissimus dorsi is then secured to replace the resected myocardium. (3) The two previous techniques of ventricular substitution and reinforcement are combined. This reconstructive procedure, which normalizes the ventricular geometrical shape, is particularly useful after extended cardiac resections, such as is done in treatment of large ventricular aneurysms, cardiac tumors, or echinococcal cyst formations. At present, improvement in ventricular function has been obtained in 12 patients at our institution. Preoperative severe cardiac dysfunction was present in all of these patients (New York Heart Association functional class III or IV). Postoperative echocardiography, multigated acquisition scan, and hemodynamic studies demonstrate an improvement in ventricular function and no impairment of ventricular compliance by the muscle flap. After a mean follow-up period of 18 months, all patients are in functional class I or II. We believe that dynamic cardiomyoplasty prolongs and improves the quality of life of patients suffering from severe chronic and irreversible myocardial dysfunction by improving ventricular contraction and limiting cardiac dilatation.

Assisted Circulation↗
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Response to atrial natriuretic peptide in dogs with acute selective intrahepatic hypertension.

Acute selective intrahepatic hypertension (IHH) is associated with the renal tubular retention of sodium in volume expanded dogs. To determine if acute selective IHH per se, without volume loading or ascites sequestration, would blunt the natriuretic response to i.v. infusions of atrial natriuretic peptide (ANP), 175 ng/kg/min of the 1-28 rat peptide was infused into 6 hydropaenic dogs where intrahepatic hydrostatic pressures were normal, and again, following the portal infusion of histamine, a maneuver known to selectively increase postsinusoidal resistance, within the hepatic microcirculation and so raise intrahepatic sinusoidal pressure. In 6 healthy dogs, while histamine 4.0 micrograms/min free base on average was being infused into a femoral vein, the infusion of ANP increased sodium excretion by 168 microEq/min, compared to 160 microEq/min when the same dose of histamine was being infused into the portal vein (portal pressure increased by 46% or 6 cm H2O). These changes in sodium excretion were not significantly different. Urine flow rate increased by 1.5 ml/min in the control phase and by 1.4 ml/min during intrahepatic hypertension (NS). Although the ANP infusion did not alter GFR or CPAH during the control phase, during IHH, ANP caused GFR to rise significantly by 20%, while there was no change to CPAH. Despite the increment in GFR, the natriuretic response during IHH was not different from that observed during the control phase of the study. We conclude that acute IHH per se does not blunt the renal tubular natriuretic response to ANP.

Animals↗
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Intestinal cryptosporidiosis and reovirus isolation from bobwhite quail (Colinus virginianus) with enteritis.

An acute enteric disease of young pen-raised bobwhite quails was studied. Affected quails had white, watery diarrhea accompanied by dehydration and subsequent death. Mortality from hatch to 17 days of age ranged from 30 to 45% in the three flocks examined. Small intestines were thin-walled and distended with fluid and gas. Microscopic lesions in the intestinal tract consisted of villus atrophy, villus fusion, and sloughing of cells at the tip of the villi in duodenum, jejunum, and ileum. Cryptosporidium sp. and reovirus were identified in affected quails.

Animals↗
PubMedDate not supplied

Peritonitis in children undergoing dialysis. 10 years experience.

The clinical aspects of peritonitis were reviewed in 83 patients treated with continuous ambulatory or continuous cyclic peritoneal dialysis between May 1978 and April 1988. Peritonitis occurred in 50 patients whose mean duration of dialysis was 17.8 months, but not in 33 patients with a mean duration of dialysis of 10.4 months. The mean time from starting dialysis to the first episode of peritonitis was 7.1 months. The peritonitis rate was lower for continuous cyclic than for continuous ambulatory peritoneal dialysis (1 episode per 12.9 vs. 1 episode per 8.1 patient months, respectively). In 39% of the episodes, gram stain of the dialysate was positive. The dialysate leukocyte count was higher in gram-negative than in gram-positive peritonitis. Seventy percent of the peritonitis episodes were gram positive, and Staphylococcus aureus was predominant. Only 1 of the 7 diapered infants had gram-negative organisms associated with peritonitis. Catheters were replaced in 48 cases, 26 because of infection. Sixty-nine percent of the patients were cured with antibiotic therapy alone. Although peritonitis was associated with a mortality rate of 1.2%, peritoneal dialysis remains the favored dialytic mode for children.

Catheters, Indwelling↗
PubMedDate not supplied

Complement activation in acute glomerulonephritis in children.

Serial determinations of complement components (C1q, C4, C3, C5 and factor B) were performed in 32 children with acute glomerulonephritis. Low levels of C3 were found in 30 patients and low levels of C5 in 26. The findings of reduced C1q and/or C4 levels (25 patients) in the first days of the disease suggest activation of the classical pathway. Depressed Factor B levels were found rarely (4 patients). In all patients, the presence of a C3 splitting activity and/of a C3 nephritic factor-like activity was investigated. Both activities were demonstrated in 7 patients whereas in another patient, only C3 splitting activity was noted. A disappearance of both activities was observed in all patients. In 3 patients tested, the C3 nephritic factor-like activity was heat-labile and was therefore not related to true C3 nephritic factor. Both pathways are implicated in the early phases of the disease but continued C3 depression is probably through alternate pathway.

Acute Disease↗