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Biomedical subjects

J Laufer

Publications and source records attributed to J Laufer.

At least 55 records · Page 3Linked to original sources
PubMed1989

Urolithiasis in children: current medical management.

The mechanism of stone formation in the urinary tract is reviewed. Diet, urinary tract infection and metabolic disorders account for the different epidemiological patterns of stone formation. The diagnosis and management of renal tract calculi are discussed. Calcium stones are associated with hypercalciuria, urine acidification defects, the use of furosemide in premature babies, hypercalcaemia, hyperoxaluria, hyperuricosuria, an alkaline urine and hypocitraturia. Uric acid stones occur in acid urine, from increased purine synthesis with lympho- or myeloproliferative disorders or from several inborn errors of purine metabolism which can also cause xanthine or dihydroxyadenine stones. Cystinuria, inherited as an autosomal recessive disorder is best treated with a low sodium diet, a fluid intake exceeding 40 ml/kg per day maintaining urine pH between 7.5 and 8 and, if necessary, with oral penicillamine. Oxalate stones occur in relation to diet, bowel disease and primary inherited defects in oxalate metabolism. Urinary tract infection causing struvite and carbonate apatite formation is the commonest cause of stones in Europe.

Child↗
PubMed1988

Plasma exchange for recurrent nephrotic syndrome following renal transplantation.

Patients with steroid-resistant nephrotic syndrome and focal segmental glomerulosclerosis (FGS) who develop end-stage renal disease are at risk for recurrence of the disease following renal transplantation. Recurrence of the nephrotic syndrome in renal allografts of two children with primary FGS was successfully controlled by plasma exchange. This report suggests that plasma exchange instituted early in the course of recurrent nephrotic syndrome may be beneficial in some patients with steroid-resistant nephrotic syndrome and FGS.

Adolescent↗
PubMed1987

[Stomatological lesions seen in HIV infection. 1. Clinical study. Apropos 111 cases].

LAV/HTL VIII virus found in 1983, renamed HIV in 1986, is doing with many clinical manifestations among which AIDS is only ultimate one, and the more serious aspect of infection by the virus. At each stage of the disease, oro-facial manifestations can be encountered, often the first one. That emphasises for oral medicine the need of perfect knowledge of these clinical aspects concerning 111 patients, we will describe these clinical aspects and hygienical and preventive precautions we choose.

AIDS-Related Complex↗
PubMed1987

[Stomatological lesions seen in HIV virus infection. II. Histopathological and ultrastructural studies].

Buccal lesions observed in the clinical setting of human immunodeficiency virus (HIV) infection constitute a diverse group of pathological entities. Several are related to the opportunistic infections observed in association with HIV infection. "Hairy leukoplakia" is a recently described benign lesion that is presumably related to infection by Epstein-Barr virus (E.B.V.). Kaposi's sarcoma is seen somewhat frequently in the oral cavity, especially involving the palate of HIV infected patients. We have observed this lesion 19 times in this location. The diagnosis is usually relatively straight-forward. Both vascular inflammatory and more typical sarcomatous morphology sub-types are present. The salivary glands may show an important lymphoplasmocytic infiltration which is unusual in that associated epithelial changes are not observed. The salivary glands seem to be a seat of the lymphocytic infiltration seen in other organs during the course of HIV infection. As for the changes encountered in the lymph nodes in HIV infection, they represent different stages in the evolution of a dynamic process, which progresses from hyperplasia to atrophy of the lymph nodes.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Anuria in a premature infant due to ureteropelvic fungal bezoars.

Systemic candidiasis with renal involvement is a well recognised complication of intensive care in premature newborns. However, the development of reversible obstructive oliguric acute renal failure has not been well documented. We report a premature infant who developed anuria associated with bilateral candidal bezoar formation in the renal collecting system. The sonographic appearance of the renal fungus balls is described. Treatment by surgical removal of the bezoars, open placement of nephrostomy tubes and intravenous antifungal therapy resulted in apparent complete recovery.

Amphotericin B↗
PubMed1986

Familial vesicoureteral reflux: a study of 16 families.

Siblings of patients with vesicoureteral reflux (VUR) are reported to have an increased incidence of reflux. We present 16 families with 33 affected children out of a total of 493 patients with VUR. Twenty-seven had urinary tract infection and 6 were asymptomatic and were examined because a sibling had VUR. Renal scarring was present in 19 cases; reflux was more marked and more often bilateral in the siblings than in sporadically affected children. In view of our findings we suggest that siblings of patients with VUR be screened early for reflux to prevent renal damage from untreated VUR.

Adolescent↗
PubMed1986

[Focal epithelial hyperplasia. Heck's disease].

A personal series of eight patients with Heck's disease is reviewed and the historical background, clinical aspects and pathologic and viral substrates of this affection discussed. No attempt is made to provide an exhaustive bibliography because of the very numerous publications on the subject. (Four clinical photography documents, 29 references concerning clinical and histologic data and a short series of 7 articles on virologic aspects).

Adolescent↗
PubMed1986

[Hemolymphangioma of the tongue treated with combination embolization-surgery. Apropos of a case].

Hemolymphangioma of the tongue is a benign vascular tumor. Episodes of activity lead progressively to the development of macroglossia which causes secondary complications. The clinical diagnosis of the tumor is confirmed by arteriography with superselective catheterisation. Arteriography assesses blood flow in the malformation, serving as a basis for classification and permitting embolisation of the tumor, the first stage of treatment.

Child, Preschool↗
PubMed1986

Comparative morphometric study of the vestibular system of the vertebrata: reptilia, aves, amphibia, and pisces.

Morphometric measurements were made from serial sections of the vestibular system in four classes of vertebrates: Reptilia, Aves, Amphibia, and Pisces. Representative species of reptile studied were the lizard (Gekko gecko), the common garter snake (Thamnophis sp.), and the common turtle (Chelonia sp.). The budgie (Melopsittacus undulatas), the common pigeon (Columba domestica), the yellow-bellied sapsucker (Sphyrapicus varius), and the horned owl (Bubo virginianus) were chosen as representative of the bird. For the amphibian, the leopard frog (Rana pipiens), and the mud puppy (Necturus maculatus) were chosen for study. As representative of the fish, the goldfish (Carassius auratus), the tilapia (Tilapia mossambica), the guppy (Lebistes sp.), and the sea horse (Hippocampus sp.) were used in these measurements. The morphometric data obtained were then used in estimates of the time constants in the Steinhausen equation which describes the biophysics of fluid flow in the semicircular canals. In general, the time constants (theta/II in the Steinhausen equation) of these representatives of Reptilia, Aves, and Amphibia were of magnitude similar to those reported in mammals, despite the dissimilarities in the diameters of the ducts, the duct radii of curvature, the dimensions of the cristae ampullares and the utricle, and volumes of endolymph within the vestibular system. However, the short-time constants in Pisces were larger (therefore providing a slower response) than those in other vertebrates, and were similar to that of the turtle and the mud puppy.

Amphibians↗
PubMed1985

Damage to the middle ear and the inner ear in underwater divers.

Postmortem human tissue from recently deceased divers was processed histologically to assess any inner and middle ear damage that could have resulted from the effects of pressure during diving. The following new findings are particularly noteworthy. In one diver, ascent while breath holding resulted in the rupture of the ear drum and blood in the middle ear, in addition to pulmonary barotrauma. In a second diver, following inner ear decompression sickness, new bone growth, similar to that described earlier in experimental studies with the squirrel monkey, was observed in the arms of one of the semicircular canals. These observations are further confirmation that otologic disorders can be a serious threat to divers.

Barotrauma↗
PubMed1984

Dimensional analysis and dynamic response characterization of mammalian peripheral vestibular structures.

Extensive morphometric measurements were made on the vestibular system of the rabbit ( Oryctulagus cuniculus), the gerbil (Meriones unguiculatus), the chinchilla (Chinchilla laniger ), and the squirrel monkey (Saimiri sciureus) from serial sections of temporal bones. Additionally, a more limited set of measurements were also completed on the owl monkey (Aotus trivirgatus), the Capuchin monkey (Cebus sp.), the harp seal ( Pagophilus groenlandicus Erxleben , 1777), and the two-toed sloth ( Choloepus sp.). The following measurements were made: 1) radius of curvature (R) of each membranous semicircular canal (herein called semicircular duct-see nomenclature in Nomina Anatomica (1968) ), 2) cross-sectional diameter of the ducts and the osseous semicircular canals, and 3) some pertinent morphometrics of the cristae ampullares and the utricle. In all species studied 1) the radii of curvature of the three semicircular ducts are dissimilar, with that of the lateral duct being as small as, or smaller than, those of the anterior and posterior ducts; 2) R for the anterior duct is largest in the harp seal and the rabbit; 3) the canal and duct dimensions are largest in the Capuchin and squirrel monkeys, the two-toed sloth, and the harp seal, and smallest in the gerbil; 4) the proportion of otic fluid "space" that is occupied by endolymph shows a ranking of gerbil greater than rabbit greater than two-toed sloth greater than chinchilla = owl monkey greater than squirrel monkey greater than Capuchin monkey greater than harp seal; and 5) the gross ampullary and utricular dimensions are largest in the harp seal and smallest in the gerbil. These measurements were used for determining the time constants describing semicircular-canal dynamics in the Steinhausen (1931, 1933) and Oman -Marcus (1980) equations.

Animals↗
PubMed1984

A one-year study of trivalent influenza vaccines in primed and unprimed volunteers: immunogenicity, clinical reactions and protection.

Three hundred volunteers were divided into two age groups, 14-30 years and 31-60 years. Each participant was immunized intramuscularly with a subunit, whole virus or absorbed whole virus vaccine, containing A/Bangkok/1/79 (H3N2), A/Brazil/11/78 (H1N1) and B/Singapore/222/79 influenza virus. Serum haemagglutination-inhibition (HI) antibody response, protection, and reactogenicity were studied after one and two doses of the vaccines. Primary immunization induced much higher percentages of HI antibody titres greater than or equal to 100 against all three vaccine viruses and much higher geometric mean titres (GMT) in volunteers with pre-immunization titres greater than or equal to 18 as compared to those with pre-immunization titres less than 18. Secondary immunization did not result in an increase of GMTs or antibody titres greater than or equal to 100 in volunteers with pre-immunization titres less than 18. On the whole, the response to the subunit vaccine was similar to that to the other two vaccines. To influenza B/Singapore/222/79 virus the response was lowest after administration of the whole virus vaccine in the age group 31-60 years. Over 50% of the HI titres greater than or equal to 100 found after immunization in the different vaccine and age groups were still present after one year. Serologically established infections during the winter months following immunization amounted to 15% in the subunit vaccine group, 6% in the whole virus vaccine group, and 10% in the adsorbed whole virus vaccine group. Local and systemic reactions to all three vaccines were mild in nature. Local reactions after primary immunization were much less frequent following administration of the subunit vaccine as compared to the other two vaccines, especially in the younger age group. In comparison to primary immunization, after booster immunization the incidence of local reactions was higher for the subunit vaccine and lower for the adsorbed whole virus vaccine. In the age group 14-30 years the incidence of local reactions after primary as well as booster immunization was much greater in females than in males, especially when the adsorbed whole virus vaccine was used.

Adolescent↗
PubMed1984

Effects of several sea anemone and scorpion toxins on excitability and ionic currents in the giant axon of the cockroach.

The membrane effects of 4 sea anemone and 6 scorpion toxins have been studied under current clamp and voltage clamp conditions. Micromolar concentrations of the purified toxins were applied externally on single giant axons of the american cockroach. Periplaneta americana in a double oil-gap arrangement and the effects on the resting potential, action potential and underlying currents analysed. The 4 sea anemone toxins (Condylactis toxin, Anemonia toxin 2, Anthopleurin toxin A and Parasicyonis toxin) were found to considerably prolong the action potential. This effect is frequency dependent and long plateau spikes (100-500 ms in duration) are consistently seen for frequencies lower than 0.2 Hz. This effect is due to a considerable delay in the turning-off of the sodium current during square membrane depolarizations associated, for large concentrations, with a decrease in the potassium conductance. Toxin effects on the sodium current are not prevented by pretreatment with STX. From the 4 purified toxins extracted from the venom of the scorpion, Androctonus australis Hector, 3 (Mammal toxins 1 and 2 and crustacean toxin) were found to have sea anemone toxin like effects and to induce long duration plateau action potentials. As for sea anemone toxins, this effect is due to a lengthening of the falling phase of the sodium current associated with a small decrease in the potassium conductance. The 4th toxin (insect toxin or ITAaH) depolarizes the membrane and induces repetitive firing of short action potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗