Miniaturization and application of the MTT assay to evaluate metabolic activity of protozoa in the presence of toxicants

This paper describes a critical evaluation of a miniaturised colorimetric assay, using MTT (3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) reduction, applied to protozoan viability testing. The toxic substances used were copper, zinc, Triton X-100 (a membrane surfactant) and cycloheximide (an inhibitor of the protein synthesis). The viability assay of the ciliate protozoan Tetrahymena pyriformis was optimised in terms of MTT concentration and incubation time. Since protozoa are non adherent cells the MTT assay was modified in order to maintain the medium in the well. MTT proved to be effective in the measurement of Tetrahymena pyriformis viability. Four hours of MTT incubation followed by 30 minutes of incubation with DMSO were found to be the best incubation times for optical density reading. Furthermore, 10 mg/ml of MTT solution was the concentration that gave higher values of optical densities with minor medium interference.

Physiological responses of Tetrahymena pyriformis to copper, zinc, cycloheximide and Triton X-100

Protozoa, and particularly ciliates, are essential in aerobic purification processes of wastewaters and have proved to be very sensitive to environmental changes. The physiological response of the ciliate Tetrahymena pyriformis was assessed in terms of mortality, growth and grazing capacity after exposure to four toxicants: copper, zinc, cycloheximide and Triton X-100. In the ranges of concentrations used, mortality, inhibition of growth and inhibition of grazing were observed with all toxicants employed, but in different ways. Copper and zinc showed lower toxicity than observed in other studies with protozoa, though some of the present results are in accordance with those reported by other authors. This supports the importance of the organism tested and the experimental conditions of the bioassays.

Effects of monensin feeding during development on female rats and their offspring

Monensin, a growth-promoting agent and coccidiostat used in veterinary medicine, was studied in terms of its effects on the development of female rats and their offspring when added to the diet. Young female rats received 100 or 300 ppm monensin mixed with powdered chow diet until adulthood, when they were mated and their offspring were evaluated for physical and neurobehavioural development. The data showed that 1) exposure to the higher monensin concentration reduced female body weight; no deaths occurred after exposure to the two monensin concentrations; 2) the offspring of the experimental group receiving 300 ppm monensin presented a weight reduction from 10 to 21 days of lactation; 3) incisor eruption was delayed only in females after exposure to the 100 ppm concentration. We conclude that exposure to monensin during development induces toxicity in female rats and has a notable adverse effect on growth with some limited effects on selective milestones of physical and functional development of the offspring during the postnatal period.

Safety and efficacy of insulin lispro in patients with diabetes mellitus

Lispro is a human insulin analogue with a very rapid onset of action, and a shorter duration of activity than soluble insulin. In order to assess the therapeutical value of lispro, we have had an open-label, non-comparative study, for 12 weeks, involving 19 IDDM patients. The treatment regimen with lispro and Humulin N has been adapted depending on each patient characteristics. Patients attended three visits, and the main metabolic control parameters included values of hemoglobin Alc, fasting and postprandial blood glucose monitoring. The patients themselves monitored their blood glucose using a glucometer. The mean age value of 19 patients (8 females and 11 males) was 22.32 (+/- 13.59) years. In patients previously receiving insulin treatment, therapy with lispro insulin significantly reduced postprandial glucose values. Lispro has been administered t.i.d. in 14 patients, and b.i.d. in 5 patients. At visit 1, mean value of HbAlc was 10.32% (+/- 1.63%); at visit 3, mean HbAlc was 9.90% (+/- 1.59%). Total insulin daily dose and the rate of short and long acting insulin did not change from visit 1 to visit 3. There has been reported only one serious adverse event during the study: a ketoacidosis due to a technical dosing error. Ten patients have reported mild hypoglycemic episodes. The outcomes of clinical study and of Quality of Life Questionnaire suggests that lispro--the first human insulin analogue used in humans--is effective, safe, and it is broadening beneficially the spectrum of insulins.

Comparative study of insulin antibodies in diabetic patients with primary insulin-dependence (type I) and secondary insulin-dependence (type II)

Insulin antibodies (% binding) were determined by RIA method in 404 insulin-treated diabetic patients divided into two groups: (A) primary insulin-dependent patients (Type I diabetes): 300 cases, 170 M, 130 F, mean age +/- SD 29.2 +/- 7.5 yrs, disease and insulin treatment duration 7.7 +/- 6 yrs: (B) Type II diabetic patients needing insulin (secondary insulin-dependence): 104 cases, 47 M, 57 F, aged 53.4 +/- 9.2 yrs, duration of diabetes 13.1 +/- 8.3 yrs, and of insulin treatment 3.1 +/- 2.1 yrs. Both groups of patients were with the same types of insulin preparations. In 297 cases, all belonging to group (A), fasting C-peptide was also determined. The titre of insulin antibodies was significantly (p less than 0.001) higher in patients with secondary insulin dependence than in those with primary insulin dependence (22.96 +/- 15.1% vs 10.25 +/- 9.89) in spite of the longer duration of insulin treatment in the later group; the mean C-peptide value found in 58 Type I diabetic patients with a binding capacity less than 10% was significantly lower (p less than 0.001) than that found in 11 Type I diabetic cases with a binding capacity greater than 20% (0.091 +/- 0.57 vs 0.273 +/- 0.37 pmol/ml); no correlation was found between insulin antibodies and metabolic control, insulin requirements or chronic complications.

[The potentials for immunization against influenza using liposome-incorporated viral surface antigens]

Studies were conducted using uni- and multilamellar liposomes to establish optimum conditions for influenza antigen incorporation in view of their transport to the target cells for experimental influenza prophylaxis in hybrid white mice. Radiometric determinations showed a good level of preparation purification, a good efficiency of incorporation in liposomes of the active biological material, the liposome linked radioactivity distribution among different organs. Charged liposomes induced solid and long lasting resistance against influenza control infection.

[Acute chondrolysis on primary protrusio acetabuli in children]

Two cases of acute chondrolysis of the upper femoral epiphysis associated with protrusio acetabuli are reported in two girls respectively 13 and 12 Y.O. The disease was unilateral in one patient and bilateral in other. Acute chondrolysis is characterized by onset of pain, restricted movements of the hip and evolution to an hip ankylosis within a few months. As usual no evidence of inflammatory disease could be shown at biology or at pathology of synovial membrane or of femoral head. CT and MR studies proved to be contributive in the first case. It's the author's opinion that in these 2 cases, chondrolysis appears as a complication of preexistent Protrusio Acetabuli.

[The multicystic kidney. Anatomo-radiological study of 19 operative specimens. Practical and pathogenic consequences]

19 specimen of pathologically proved multicystic kidneys were opacified; first through the ureter and second, if the ureter was not patent, through a puncture of one of the cysts (or several if the first cyst did not communicate with the ureter or with other cysts). The results are as follows. The ureter was hypoplastic but patent in 12 and communicated with some of the cysts in 9 or with all the cysts in 3. These communications consisted of large (12 cases) or small (15 cases) canals, or both large and small canals (11 cases). When patent, the ureter was connected to these canals. Moreover in most of the cases, there was a communication between cysts through such canals. Finally, only 3 cases fitted with the classical description having an atretic ureter and non communicating cysts. Our conclusion is that the same basal defect is present in congenital obstructions of pelvis and calyces; there is a continuous spectrum of malformations between congenital hydronephrosis, hydrocalyces and multicystic kidneys.

[Pseudo-ureteroceles resulting from the impression of a loop of a megaureter with an ectopic subvesical orifice]

The authors report 3 rare cases of pseudo-ureteroceles corresponding to a vesical imprint of an ectopic extra-vesical megaureter. When an ectopic extra-vesical ureter follows a sharp juxta-vesical buckle, it can give a deep imprint on the bladder and look similar to an ureterocele. I.V.P. and U.S. can be as misleading since the appearance of this type of megaureter and ureterocele can be similar, and differential diagnosis can be difficult. Such situations are rare. In a ten years of pediatric urologic practice, the authors who have investigated 51 ureteroceles and 26 extravesical ectopic ureters, have only observed 3 children with this lesion. These 3 cases corresponded to two simple ureters, in a 3 year old boy and in a 2.5 year old girl, and one upper ureter of a complete duplex system in a neonate baby girl with antenatal discovery. The clinical, radiological, sonographical and endoscopic clues to the diagnosis are discussed and illustrated.

Intra-renal reflux: a new cause of medullary hyperechogenicity?

A 5-month-old infant with untreated severe urinary tract infection and bilateral vesico-ureteral reflux, had diffuse intrarenal reflux and hyperechogenicity of the medulla of two normal sized kidneys. We discuss the hyperechogenicity of the medulla in relationship to the intrarenal reflux.

[Giant Meckel's diverticulum presenting as tumor]

The authors report a case of giant Meckel's diverticulum, presenting as a subumbilical abdominal mass, associated with an infectious picture and anemia in a 16 month-old boy. Epidemiologic, pathologic and clinical features of this rare disorder are reviewed as are the diagnostic means. The differential diagnosis with other cystic masses of the umbilical area (omphalo-mesenteric duct cyst, urachal cyst, mesenteric cyst, duplication) is discussed.

[Osteoid osteoma of the femur neck with synovitis simulating chronic monoarthritis of the hip]

The authors report a case of subperiosteal osteoid osteoma of the femoral neck in a 14 year-old girl presenting as chronic hip monoarthritis with narrowed coxofemoral joint space and non specific histological synovitis. They analyse the synovitis which is associated with some osteoid osteomas (hip, elbow, knee, ankle bones) emphasizing the "pseudo-arthritis of the hip" picture and insist that all cases of unexplained chronic monoarthritis of the hip should suggest subperiosteal osteoid osteoma of the neck.

Ultrasonography of hepatic cavernous haemangiomas

Cavernous haemangiomas, the most frequent benign tumours of the liver, are discussed by the authors in connection with 50 personal cases and surveillance of 35 solitary hyperechoic nodules less than 3 cm diam. without clinical or biological abnormalities. All the diagnostic images are reviewed but attention is focussed on ultrasound. All US patterns may be observed, but if the lesion is less than 3 cm, the echostructure is often hyperechoic and homogeneous. In view of their asymptomatic nature and the absence of risk of evolution for these small hyperechoic lesions, it appears legitimate to propose surveillance merely by US if there are no clinical symptoms and if liver function tests are normal.

[Radiologic study of aberrant pancreas of gastroduodenal topography. Apropos of 11 cases]

In connection with 11 observations of aberrant pancreas in the gastro-duodenal area, the authors review the general and radiological features of this pathology. In ten of the personal cases reported on, radiological examination allowed diagnosis following discovery of an intramural image centered around an umbilication. While not uncommon, pancreatic heterotopias are generally fortuitous findings due to the usual absence of clinical symptoms. They are small, and tend to occur in the digestive tract, especially in the antro-duodenal region. Possible complications include adenomatous transformation which may or may not be insulinogenic, cystic degeneration, cystenadenoma and carcinoma. Such complications are rare, however, and are generally not discovered before surgery. Radiological examinations were negative in 23,7% of the cases reviewed; while the typical image of a rounded filling defect centered around an umbilication is easy to diagnose, the value of radiology is considerably less when dealing with peduncular, subserous or complex forms. Although certain authors recommend only surveillance following radiological and endoscopic detection of a small aberrant pancreas, the majority of authors advise exeresis.

Indications for ultrasonography in parotid pathologies

In connection with 141 cases of parotid tumours, 21 adenopathies of the parotid region and 22 cases of parotitis, the authors define the role of ultrasonography in the exploration of the salivary glands. Use of simple criteria permits differentiation of benign from malignant tumours with a good degree of sensitivity (79.8% in our series). This score allows ultrasonography to be offered as the first complementary examination when dealing with a tumefaction of the parotid region. When ultrasonographic findings evoke a malignant lesion, a CT scan seems necessary to evaluate any extension in depth. In contrast, ultrasonography does not appear justified in cases of parotitis or lithiasic pathologies.

Stimulation by inlfuenza virus RNA of 3H-phenylalanine incorporation in a cell-free system

Purified and unpurified cell-free systems prepared from the chorioallantoic membrane of embryonated eggs were tested for polypeptide synthesis in the presence and absence of influenza virus RNA. Both systems exhibited an endogenous messenger activity determining 3H-phenylalanine incorporation into polypeptides in the absence of virus RNA. However, addition of influenza virus RNA to the systems clearly stimulated amino acid incorporation into polypeptides, offering the possibility of studying some aspects of the viral protein biosynthesis mechanism.