Flow injection photometric determination of zinc and copper with zincon based on the variation of the stability of the complexes with pH.

A flow injection photometric method for the sequential determination of zinc and copper in mixtures was developed based on the variation of the stability of the chromogenic complexes between the analytes and the reagent zincon with pH. At pH 5.0 only the Cu-zincon complex exists, whereas at pH 9.0 the copper and zinc chelates co-exist. A three-channel manifold was implemented containing two alternating buffer streams (pH 5 and 9) which permit the colored reaction products to be formed sequentially at both pH values, and consequently the mixtures can be resolved. A continuous preconcentration unit (Chelex-100) was used in order to increase the sensitivity of the method, thus allowing the analysis of water samples in which the analytes are present at the ng ml-1 level. On the other hand, preconcentration was not required when the analytes were determined in brass. Under the optimum conditions and using a preconcentration time of 2 min, the detection limits (3 sigma) were found to be 0.35 and 0.80 ng ml-1 for zinc and copper, respectively. The repeatability of the method, expressed as the RSD, was in all instances less than 3.1%. Considering the sequential determination of both species, a sampling rate of 70 h-1 was obtained if preconcentration of the samples was not required.

[Acute kidney failure due to kidney cortex necrosis. 2 clinical cases of surviving patients]. / Insuficiencia renal aguda por necrosis cortical renal. Dos casos clínicos de pacientes sobrevivientes.

A 22 year old female developed preeclampsia with fetal death in utero. After cesarean section she developed uterine inertia and acute hemorrhagic anemia complicated by sepsis, disseminated intravascular coagulation and total anuria for 4 weeks. She was treated with hemodialysis. The second patient, a 49 year old man developed sepsis and intravascular coagulation after a dog bite. Acute renal failure with a 3 week total anuria followed. He was initially treated with peritoneo dialysis. Renal biopsy showed evidence of renal cortical necrosis in both patients.

[Suckling mouse brain rabies vaccine supplemented with an adjuvant. Its use in cattle]. / Vacuna antirrábica de cerebro de ratón lactante suplementada con adyuvante. Su aplicación en bovinos.

This paper describes two experiments carried out in cattle immunized with suckling mouse brain rabies vaccine (SMB) 14, supplemented with 2% Al (OH)3 15 or Freund's modified incomplete adjuvant 2, 26. When determining the vaccinal dose, it was observed that the immune response was independent from the doses used (Table 1), all animals survived the challenge 30 days after vaccination, as compared to a mortality rate of 80% in the controls. To determine the duration of immunity, an amount of 5 ml was chosen as vacinal dose. Two years after immunization, both vaccines protected 96% of the cattle against a viral challenge that killed 63% of the non-vaccinated controls (Table 2). Statistically significant differences were observed between the antibody levels elicited by both vaccines. Antibody levels observed with the oil supplemented vaccine were higher than those produced by the A1 (OH)3 vaccine.

Vacuna antirrábica de cerebro de ratón lactante suplementada con adyuvante. Su aplicación en bovinos / [Suckling mouse brain rabies vaccine supplemented with an adjuvant. Its use in cattle]

This paper describes two experiments carried out in cattle immunized with suckling mouse brain rabies vaccine (SMB) 14, supplemented with 2

Al (OH)3 15 or Freund’s modified incomplete adjuvant 2, 26. When determining the vaccinal dose, it was observed that the immune response was independent from the doses used (Table 1), all animals survived the challenge 30 days after vaccination, as compared to a mortality rate of 80

in the controls. To determine the duration of immunity, an amount of 5 ml was chosen as vacinal dose. Two years after immunization, both vaccines protected 96

of the cattle against a viral challenge that killed 63

of the non-vaccinated controls (Table 2). Statistically significant differences were observed between the antibody levels elicited by both vaccines. Antibody levels observed with the oil supplemented vaccine were higher than those produced by the A1 (OH)3 vaccine.

Vacuna antirrábica de cerebro de ratón lactante suplementada con adyuvante. Su aplicación en bovinos. / [Suckling mouse brain rabies vaccine supplemented with an adjuvant. Its use in cattle]

This paper describes two experiments carried out in cattle immunized with suckling mouse brain rabies vaccine (SMB) 14, supplemented with 2

Al (OH)3 15 or Freunds modified incomplete adjuvant 2, 26. When determining the vaccinal dose, it was observed that the immune response was independent from the doses used (Table 1), all animals survived the challenge 30 days after vaccination, as compared to a mortality rate of 80

in the controls. To determine the duration of immunity, an amount of 5 ml was chosen as vacinal dose. Two years after immunization, both vaccines protected 96

of the cattle against a viral challenge that killed 63

of the non-vaccinated controls (Table 2). Statistically significant differences were observed between the antibody levels elicited by both vaccines. Antibody levels observed with the oil supplemented vaccine were higher than those produced by the A1 (OH)3 vaccine.

Laboratory investigations on neuroparalytic accidents associated with suckling mouse brain rabies vaccine. III. -- Preservation of vaccine potency after elimination of murine brain myelin by centrifugation.

Myelin, which has been found in nine day-old mouse brain, was eliminated from weanling mouse brain suspensions by centrifugation at 17,000 g for 10 min, as demonstrated by electron microscopy and guinea-pig inoculation tests for encephalitogenic activity. This centrifugation procedure did not affect the potency of seven batches of suckling mouse brain vaccine, when centrifuged and non-centrifuged samples of the same batches were compared by a modified NIH potency test (t = 0.17). The present results with weanling mouse brain preparations suggest that centrifugation at 17,000 g be used in the preparation of rabies suckling mouse brain vaccine instead of the 1,900 g currently employed, which does not eliminate myelin. This new procedure would be expected to reduce the number of postvaccinal reactions which are attributable to the small amount of myelin which remains in vaccines prepared with new-born animal brains following the current procedure.

Recovery from rabies in man.

A 45-year-old woman from Mendoza, Argentina, was severely bitten by a dog that died 4 days later. Before death, the dog was nervous, aggressive, and had occasional seizures. Ten days after the woman had been bitten, rabies vaccine treatment was begun: 14 daily doses of suckling mouse brain vaccine followed by 2 booster doses. Twenty-one days after the biting episode, she developed a cerebellar striatal syndrome, which persisted throughout several months, and severe encephalitic symptoms, which persisted for 75 days. After 13 months, recovery was nearly complete. The patient's serum and cerebrospinal fluid contained rabies-neutralizing antibodies reaching maximum titers of 1:640 000 and 1:160 000, respectively. Titers of this magnitude have never been previusly recorded after suckling mouse brain vaccine treatment. This phenomenon, together with the epidemiologic, clinical, and laboratory data presented, supports the conclusion of a nonfatal case of rabies in man.

Non-fatal rabies in dogs and cats.

Serological studies were performed in 1,015 dog brains and 144 cat brains collected in a rabies enzootic area. Significant levels of rabies virus neutralizing activity were observed in two dog brains and in one cat brain which had been negative for rabies by immunofluorescence and mouse inoculation tests. These results were compared with those obtained in the group of surviving animals at different times after onset of experimentally induced abortive rabies. The possibility that naturally infected animals recovered from rabies central nervous system infection is suggested.

Presence of rabies neutralizing antibodies in wild carnivores following an outbreak of bovine rabies.

In an outbreak of bovine rabies in Argentina, a study was made of vampire bats (Desmodus rotundus) and wild carnivores. Rabies antibody rates of high prevalence were found in the bats, foxes (Dusicyon gymnocercus) and skunks (Conepatus chinga). The outbreak was part of an extensive continuing epizootic of vampire transmitted bovine rabies which may have also involved other vectors in the area of this study. Consumption of dead and dying bats by the carnivores is the suggested means of passage of rabies virus from vampire bats to foxes and skunks. Given optimum conditions it is conceivable that some outbreaks in carnivores may begin in this way.

Observations on the epizootiology of vampire bat rabies.

Vampire bat populations were opportunely sampled before, during, and at varying intervals after outbreaks of bovine rabies. The captured bats were examined for rabies neutralizing antibody and virus. In all, sera from 1,024 vampire bats were tested for antibody, and tissues from these bats plus 83 others were tested for virus. Neutralizing antibody only rarely appeared in vampire serum samples taken before bovine rabies outbreaks, and only low percentages of samples positive for rabies antibody were obtained from bats captured during bovine outbreaks. In contrast, varying percentages of positive samples (including some high percentages) were taken from bats captured at various intervals after bovine outbreaks. Only eleven rabies virus isolations were obtained in the course of this study. In each case the virus came from a bat captured just before or during a bovine outbreak. The authors suggest that rabies virus behaves in vampire populations the way diverse infectious agents typically behave in other hosts. That is, the virus infects many individuals; some die and others survive to demonstrate their exposure through the appearance of anitbody. The disease disappears from the bat population in time and does not return until a sufficient number of susceptible bats have re-entered the population.