Reduction of latex-allergen content in Swedish medical catheter balloons – a survey of 3 years' production

Anaphylactic reactions after intravascular exposure to natural rubber latex (NRL) have been reported. Thus, there is an urgent need to produce medical devices with the lowest possible latex-allergen content. The latex-allergen concentration in extracts prepared from 92 lots of medical catheter (MC) balloons, manufactured by Nolato Polymer AB, Torekov, Sweden, from April 1993 to March 1996, was measured with an EAI (IgE antibody inhibition) assay. Inhibitory capacity was expressed in arbitrary units/ml (U/ml) in relation to reference NRL sap, given an arbitrary value of 1000 U. Extracts from randomly selected lots were measured for protein by the modified Lowry method. Water leaching, chlorination, and treatment with savinase were used experimentally to study reduction of the latex-allergen content. The latex-allergen content in extract from the regular MC balloons varied from 0.1 to 2.9 U/ml. All the methods used to reduce the allergen content were effective, and increased leaching stabilized the allergen content at a low level. The protein concentration of the extracts varied between 9 and 100 mg/1. No correlation was found between protein and allergen content. As a result of this study, the manufacturer has extended the stage of water leaching in the production process. This study shows that cooperation between immunologists and manufacturers may result in product development and improvement.     

Behavioral effects of stimulating positive reward sites in the central tegmentum of rhesus monkeys.

Rhesus monkeys with electrodes chronically implanted in reward sites in central tegmentum were given telemetered brain stimulation while they were free ranging alone or with cagemates. Stimulation seemed to induce a relaxed positive affect as measured by increased huddling, increased lipsmacking, reduced muscle tone, increased solicitation of grooming and increased grooming of other monkeys. Stimulation did not increase dominant/submissive interactions and seemed to have no effect on aggression or fear. These results are very different from those obtained from an anterolateral hypothalamic self-stimulation site and indicate that fibers which provide input from this area to anterolateral hypothalamus are not solely responsible for effects obtained in the anterolateral hypothalamic area.     

The ophthalmic artery and its branches,measurements and clinical importance

Summary Seventy-one Caucasian orbits (36 right, 35 left) were studied by dissection. The diameter of the ophthalmic a. (2 mm from the origin) was 1.54 ± 0.04 mm (male) and 1.31 ± 0.05 mm (female). In individual cases, there were no significant differences in vessel diameter between the right and left sides but, differences in vessel diameter between males and females were more commonly observed in the arteries which leave the orbit (extraorbital group), the individual vessels having a larger diameter in males. The incidence of the ophthalmic a. passing in the orbit medially under the optic n. was 18.6%. The lacrimal a. was observed to arise from the ophthalmic a. in only 82.5% of the cases examined, 15.9% of the cases showed the origin to be at the anastomotic branch of the middle meningealThis article is dedicated to Pr Dr Hoepke on occasion of his 100th birthday     

Pitfalls in acid/base experiments with conscious dogs

Arterial pH and blood gases were measured at intervals in conscious dogs after their first human contact of the day. Blood was sampled through an indwelling catheter in the aorta without disturbing the animals. It appeared that in the first 90 min arterial PO₂, oxygen saturation and haemoglobin concentration significantly declined. PCO₂ and pH changed less consistently when the acid/base status of the dogs was normal, but when a non-respiratory acidosis was present there was a significant decrease in pH and a significant increase in PCO₂. Arterial pH and blood gases were also measured before and after feeding the animals. It appeared that an appreciable metabolic alkalosis developed within 2 h after a meal. The alkaline tide was accompanied by a trend to higher values for PCO₂. It is concluded that, after a period of seclusion, renewed human contact causes behavioural changes in a dog, which may result in appreciable transitory changes in arterial pH and blood gas values. Blood sampling from conscious dogs should therefore take place after a proper period of habituation; preferably, a few samples should be taken at intervals to check that a steady state has been reached. If possible, blood should be collected before feeding; in any case the relationship in time of blood sampling to feeding should be constant throughout.     

Extensive immune-mediated hippocampal damage in mice surviving infection with neuroadapted Sindbis virus

Viral infections of the central nervous system and immune responses to these infections cause a variety of neurological diseases. Infection of weanling mice with Sindbis virus causes acute nonfatal encephalomyelitis followed by clearance of infectious virus, but persistence of viral RNA. Infection with a neuroadapted strain of Sindbis virus (NSV) causes fatal encephalomyelitis, but passive transfer of immune serum after infection protects from fatal disease and infectious virus is cleared. To determine whether persistent NSV RNA is associated with neurological damage, we examined the brains of recovered mice and found progressive loss of the hippocampal gyrus, adjacent white matter, and deep cerebral cortex associated with mononuclear cell infiltration. Mice deficient in CD4(+) T cells showed less tissue loss, while mice lacking CD8(+) T cells showed lesions comparable to those in immunocompetent mice. Mice deficient in both CD4(+) and CD8(+) T cells developed severe tissue loss similar to immunocompetent mice and this was associated with extensive infiltration of macrophages. The number of CD4(+) cells and macrophage/microglial cells, but not CD8(+) cells, infiltrating the hippocampal gyrus was correlated with the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling positive pyramidal neurons. These results suggest that CD4(+) T cells can promote progressive neuronal death and tissue injury, despite clearance of infectious virus.     

Three novel PROC gene lesions causing protein C deficiency

Hallam PJ, Mannucci P, Tripodi A, Bevan D, Laursen B, Tengborn L, Wacey A, Cooper DN. Three novel PROC gene lesions causing protein C deficiency. Clin Genet 1998: 54: 231–233. 0 Munksgaard, 1998
Missense mutations. three of them novel (Am210→Val, Asn248→ Ile, Ah355→Val), were found in the protein c ( PROC ) genes of 7 patients with inherited protein C deficiency associated with venous thrombosis. Comparison with the phenotypic effects of mutations in the analogous residues of factor IX causing hdernophilia B and the use of molecular modelling has provided explanations as to how these lesions might alter either the structure, function or secretion of the protein C molecules encoded.     

Influence of Various Immunomodulators on the Induction of Experimental Autoimmune Encephalomyelitis in Lewis Rats

The effect of various immunomodulators on the induction of experimental autoimmune encephalomyelitis (EAE) is evaluated in the Lewis rat. Bordetella pertussis (BP) is the optimal inductor of EAE in this rat strain. Treatment of the animals with BP either before or after or simultaneously with guinea-pig spinal cord preparation (GpSC) resulted in an EAE about two weeks thereafter. Additional injection of living BCG, of CFA, IFA (incomplete Freund's adjuvant) or Vibrio cholerae neuraminidase (VCN) did not augment or mitigate the effect induced by BP or GpSC. Living BCG, IFA, VCN or Corynebacterium parvum (CP) did not induce EAE when given in combination with GpSC but without BP. CFA combined with GpSC only occasionally induced EAE. However, EAE could be induced by the combination of CFA and GpSC or IFA and GpSC in a part of the animals tested if they had been pretreated or simultaneously been injected with living BCG by intravenous route. EAE could not be enhanced by the additional injection of VCN. Surprisingly, most of the animals peracutely died after injection of CFA and BP in combination with GpSC when they had been pretreated with CP. This effect was most pronounced when pretreatment was done on day -4. No acute effect could be seen when CP was given simultaneously to CFA, BP and GpSC. Animals which did not peracutely succumb developed EAE similarly as those in the positive control groups. CP treatment simultaneously with BP but without CFA resulted in a reduction of the EAE specific mortality. This reduction could not be seen if treatment with CP was done after injection of GpSC and BP.     

ACh and 5-HT stimulated thermogenesis at different core temperatures in the He-Cold hypothermic hamster

Hamsters in deep experimentally induced hypothermia, at body temperatures between 7 degrees C and 11.5 degrees C, were microinjected with 5-HT and ACh at brain sites in the anterior-preoptic area of the hypothalamus (AH/POA). ACh or 5-HT was injected into an AH/POA site at different starting core temperatures in different groups of hypothermic hamsters. Colonic temperatures (Tc) were maintained, following He-Cold induction, in a temperature controlled environmental chamber and measured with a YSI thermister probe and YSI telethermometer. Injections of either 5-HT or ACh at Tc's between 7.0 degrees C and 9.0 degrees C elicited only modest increases in Tc i.e., 0.3 degrees C--0.6 degrees C, respectively. As Tc increased, however, to ranges between 9.1 degrees C--10.0 degrees C and in different animals to greater than 10 degrees C both ACh and 5-HT at the same sites elicited significant increases in Tc, 1.5 degrees C for 5-HT and 2.2 degrees C for ACh compared to saline injections. These data suggest that at the lowest Tc's we are observing a "cold block" of temperature sensitive sites in the AH/POA. Increasing the starting Tc beyond 9.0 degrees C however, evokes significant increases in heat-gain following AH/POA injection of either ACh or 5-HT. These data are consistent with Myers' observations concerning the organization of heat-gain mechanisms at AH/POA sites. In addition, they suggest that both the afferent limb of the heat-gain circuit (5-HT) and the efferent limb of the circuit (ACh) are functionally impaired when Tc is close to the physiological limit in the He-Cold hypothermic hamster.