Effect of low-phytate barley or phytase supplementation to a barley-soybean meal diet on phosphorus retention and excretion by grower pigs

Two studies were conducted to determine the effect of diets containing low-phytate barley or supplemented with phytase on P balance and excretion in grower pigs. In Exp. 1, eight 32-kg barrows were assigned to a repeated, 4 x 4 Latin square design and fed 4 diets that contained 96% barley: normal-phytate hulled barley (HB), low-phytate hulled barley (LPHB), normal-phytate hull-less barley (HLB), and low-phytate hull-less barley (LPHLB). The barley cultivars contained 0.16, 0.05, 0.24, and 0.03% phytate, respectively. Inorganic P (iP) was added to the HB and HLB diets to meet the 1998 National Research Council recommendation of available P (aP, 0.23%), whereas LPHB and LPHLB contained sufficient aP. The diets were fed at 2.5 times the maintenance requirement for ME. The apparent total tract digestibilities (ATTD) of P did not differ between the hulled and hull-less barley diets, but P retention (%) and excretion were greater in pigs fed the hull-less barley diets (P < 0.05). The ATTD of P was greater and P excretion was 35% lower in pigs fed the low-phytate compared with the normal-phytate diets (P < 0.001). The amount of P retained (g/d) was greater (P < 0.001) in pigs fed low-phytate barley, reflecting an ATTD of P of 65 and 49% for low-phytate and normal-phytate barley, respectively (P < 0.001). In Exp. 2, eight 21-kg barrows were assigned to a repeated, 4 x 4 Latin square design and fed 4 diets based on barley and soybean meal (SBM): HB-SBM, HB-SBM + iP, HB-SBM + phytase, and LPHB-SBM. The HB-SBM and HB-SBM + phytase diets were deficient in aP, whereas the HB-SBM + iP and LPHB-SBM diets had adequate aP. The feeding regimen was similar to that of Exp. 1. Adding iP to the HB-SBM diet did not affect the ATTD but increased the amount of P retained (g/d) and excreted (P < 0.001). The ATTD and amount of P retained (g/d) did not differ among pigs fed the HB-SBM + iP, HB-SBM + phytase, and LPHB-SBM diets. However, pigs fed the HB-SBM + phytase and LPHB-SBM diets excreted 32 and 29% less P, respectively, than pigs fed the HB-SBM + iP diet (P < 0.05), confirming that low-phytate barley is as effective as supplemental phytase in improving P digestibility and utilization and decreasing P excretion in grower pigs.

Effect of dietary protein content on ileal amino acid digestibility, growth performance, and formation of microbial metabolites in ileal and cecal digesta of early-weaned pigs

Diarrhea incidence in weaned pigs may be associated with the concentration of intestinal microbial metabolites (ammonia, amines, and VFA) that are influenced by dietary CP content. Three experiments were conducted to determine effects of a low-protein, AA-supplemented diet on ileal AA digestibility, growth performance, diarrhea incidence, and concentration of microbial metabolites in ileal and cecal digesta of pigs weaned at 14 d of age. In Exp. 1, 8 pigs fitted with a simple T-cannula at the distal ileum were assigned in a crossover design to 2 diets containing 24 or 20% CP using wheat, corn, full-fat soybeans, whey powder, fish meal, and blood plasma as the main ingredients. Supplemental AA were added to the diets to meet the AA standards according to the 1998 NRC recommendations. Chromic oxide was used as an indigestible marker. Diets were fed at 2.5 times the ME requirement for maintenance. The reduction of dietary CP decreased (P < 0.05) the apparent ileal digestibility of most AA, except Lys, Met, Thr, Val, and Pro. Dietary CP content did not affect the pH of ileal digesta or ileal concentrations of ammonia N, cadaverine, putrescine, or VFA. In Exp. 2, 8 pigs fitted with a simple T-cannula in the cecum were assigned to 2 diets, similar to Exp. 1. Dietary CP content did not affect the pH of cecal digesta. The reduction in CP content decreased (P < 0.05) cecal ammonia N, acetic acid, isobutyric acid, isovaleric acid, total VFA, and putrescine concentrations by 28 to 39%. In Exp. 3, 32 pigs were assigned to 2 diets, similar to Exp. 1, according to a randomized complete block design. Pigs had free access to feed and water. Dietary CP content did not affect growth performance or fecal consistency scores during the 3-wk study, and diarrhea was not observed. The results of these experiments indicate that lowering the dietary CP content combined with supplementation of AA markedly reduced the production of potentially harmful microbial metabolites in cecal digesta of early-weaned pigs without affecting growth performance.

Role of weight-based ribavirin dosing and extended duration of therapy in chronic hepatitis C in HIV-infected patients: the PRESCO trial

The response to pegylated interferon (pegIFN) plus ribavirin (RBV) as treatment of chronic hepatitis C virus (HCV) infection is lower in HIV-coinfected than in HCV-monoinfected patients and could be due to suboptimal RBV dosing and/or insufficient duration of therapy in prior trials. In a prospective, multicenter, open, comparative trial, HCV/HIV-coinfected patients received pegIFN plus weight-based RBV for 48 or 72 weeks (HCV genotypes 1 and 4) and 24 or 48 weeks (HCV genotypes 2 and 3). Use of didanosine was not allowed. Out of 389 patients included in the trial, 61% were infected by HCV-1/4 and 67% had serum HCV-RNA >500,000 IU/ml. Sustained virological response (SVR) was achieved by 49.6%, significantly higher in HCV-2/3 than HCV-1/4 (72.4% vs. 35%; p < 0.0001). A high drop-out rate in the longer treatment arms precluded obtaining definitive conclusions about the efficacy of prolonging therapy. Premature treatment discontinuations due to serious adverse events occurred in 8.2%. Infection with HCV-2/3, lower baseline HCV-RNA, and negative HCV-RNA at week 12 were all independent predictors of SVR in the multivariate analysis. The use of RBV 1000-1200 mg/day plus pegIFN is relatively safe and provides SVR in nearly half of coinfected patients, twice as high in HCV-2/3 than HCV-1/4.

Premature Treatment Discontinuation in HIV/HCV-Coinfected Patients Receiving Pegylated Interferon plus Weight-Based Ribavirin

Background

Chronic hepatitis C therapy in HIV patients is often penalized by more frequent premature treatment discontinuations. It is unclear what the relative contribution of more adverse events and/or early virological failures are.

Methods

PRESCO was a prospective, multicentre, comparative trial, in which 389 HIV/HCV-coinfected patients with CD4+ T-cell counts >300 cells/ml and elevated aminotransferases received pegylated interferon-α2a (peg IFN-α2a) 180 mg per week plus ribavirin (RBV) 1,000–1,200 mg daily. Patients with HCV genotypes 1 or 4 were treated for 48 or 72 weeks while HCV genotypes 2 or 3 carriers were treated for 24 or 48 weeks. Use of didanosine was not allowed.

Results

Sustained virological response (SVR) was achieved by 193 (49.6%), and was significantly greater in HCV-2/3 than in HCV-1/4 patients (72.4% versus 35%; P<0.0001). Premature treatment discontinuations occurred in 174 patients (44.7%). This was due to early virological failure in 66 (17%), serious adverse events in 32 (8.2%), loss-to-follow-up in 12 (3.1%) and voluntary withdrawal in 64 (16.4%). Only 10 patients (2.6%) stopped HCV therapy due to severe anaemia. Two patients stopped HCV medication due to symptomatic mitochondrial toxicity. There were no episodes of hepatic decompensation.

Conclusions

Treatment with RBV 1,000–1,200 mg/day plus peg IFN-α2a is relatively safe and provided SVR in nearly half of the HIV/HCV-coinfected patients, twice as many amongst the HCV-2/3 than HCV-1/4 carriers. Avoidance of didanosine, limited use of zidovudine and therapy restricted to patients with CD4+ T-cell counts >300 cells/ml most probably explains the lower and different spectrum of serious adverse events in PRESCO compared with prior trials conducted in coinfected patients.

The effect of feeding low-phytate barley-soybean meal diets differing in protein content to growing pigs on the excretion of phosphorus and nitrogen

An experiment was conducted with growing pigs to determine the excretion of P and N in 4 barley-based diets formulated to contain 18 or 15% CP by using a normal barley (NB) or a low-phytate barley (LPB). The NB contained 0.31% total P and 0.19% phytate P; the LPB contained 0.32% total P and 0.01% phytate P. The diets were supplemented, when so required, with lysine, methionine, threonine, and tryptophan to meet their apparent ileal digestible supplies according to the NRC (1998). The diets containing NB were supplemented with inorganic P to meet the NRC (1998) recommendation for available P (0.23%). The diets containing LPB were not supplemented with inorganic P because these contained sufficient available P (0.27%). Eight barrows with an average BW of 20.9 kg were assigned to the 4 dietary treatments according to a repeated 4 x 4 Latin square design. The diets were fed at a rate of 2.5 times the ME requirement for maintenance. The barrows were fed twice daily, at 0800 and 1500, equal amounts each meal. Water was added to the feed at a ratio of 2.5:1. Each experimental period consisted of a 7-d adaptation period followed by a 5-d collection of feces and urine. The substitution of NB with LPB decreased (P < 0.001) the total P excretion by 38 and 43% for the 18 and 15% CP diets, respectively. Reducing the CP content from 18 to 15% decreased (P < 0.001) the N excretion by 29 and 32% for the NB and LPB diets, respectively. With the reduction in CP content, there was a decrease (P < 0.001) in the amount of N retained. The N:P ratio in manure of pigs fed the LPB diets was greater (P < 0.001) than from pigs fed the NB diets. These data indicate that P and N excretion can be greatly reduced by substitution of NB by LPB, and also by the reduction of the CP content, in diets for growing pigs.

Premature treatment discontinuation in HIV/HCV-coinfected patients receiving pegylated interferon plus weight-based ribavirin

BACKGROUND

Chronic hepatitis C therapy in HIV patients is often penalized by more frequent premature treatment discontinuations. It is unclear what the relative contribution of more adverse events and/or early virological failures are.

METHODS

PRESCO was a prospective, multicentre, comparative trial, in which 389 HIV/HCV-coinfected patients with CD4+ T-cell counts >300 cells/ml and elevated aminotransferases received pegylated interferon-alpha2a (peg IFN-alpha2a) 180 mg per week plus ribavirin (RBV) 1,000-1,200 mg daily. Patients with HCV genotypes 1 or 4 were treated for 48 or 72 weeks while HCV genotypes 2 or 3 carriers were treated for 24 or 48 weeks. Use of didanosine was not allowed.

RESULTS

Sustained virological response (SVR) was achieved by 193 (49.6%), and was significantly greater in HCV-2/3 than in HCV-1/4 patients (72.4% versus 35%; P<0.0001). Premature treatment discontinuations occurred in 174 patients (44.7%). This was due to early virological failure in 66 (17%), serious adverse events in 32 (8.2%), loss-to-follow-up in 12 (3.1%) and voluntary withdrawal in 64 (16.4%). Only 10 patients (2.6%) stopped HCV therapy due to severe anaemia. Two patients stopped HCV medication due to symptomatic mitochondrial toxicity. There were no episodes of hepatic decompensation.

CONCLUSIONS

Treatment with RBV 1,000-1,200 mg/day plus peg IFN-alpha2a is relatively safe and provided SVR in nearly half of the HIV/HCV-coinfected patients, twice as many amongst the HCV-2/3 than HCV-1/4 carriers. Avoidance of didanosine, limited use of zidovudine and therapy restricted to patients with CD4+ T-cell counts >300 cells/ml most probably explains the lower and different spectrum of serious adverse events in PRESCO compared with prior trials conducted in coinfected patients.

Effect of phytase supplementation to a low- and a high-phytate diet for growing pigs on the digestibilities of crude protein, amino acids, and energy1,2,3

Supplementation of microbial phytase usually improves the digestibility and utilization of phosphorus in feedstuffs of plant origin. The effect of phytase supplementation on the digestibilities of AA also has been examined, but the results have been inconsistent. This study was carried out to determine the effect of phytase (Natuphos) supplementation, at a rate of 2,000 phytase units/kg, to two basal diets on the apparent ileal digestibilities (AID) of GE, CP, and AA, and on the apparent total-tract digestibilities (ATTD) of CP and GE. The basal diets contained 18% CP and were formulated (as-fed basis) to contain either a low (0.22%) or high content (0.48%) of phytate P. The high-phytate diet contained 20% rice bran, which is a rich source of phytate and has low intrinsic phytase activity. Eight barrows (average initial BW = 40.6 kg), fitted with a simple T-cannula at the distal ileum, were fed the four diets according to a replicated 4 x 4 Latin square design. The pigs were fed twice daily at 0800 and 2000, equal amounts each meal, at a rate of 2.4 times the daily maintenance requirement for ME. Each experimental period comprised 14 d. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Feces were collected from 0800 on d 8 until 0800 on d 12. Chromic oxide was used as the digestibility marker. The AID of GE, CP, and AA and the ATTD of CP and GE were less in the high- than in the low-phytate diet (P < 0.01). With the exception of glutamic acid, phytase supplementation did not affect (P > 0.10) the AID of CP and AA. There was no effect (P > 0.05) of phytase on the ATTD of CP and GE. These results show that if a response occurs to phytase supplementation, it is independent of the dietary phytate content.

Amino acid and energy digestibility in different sources of rice bran for growing pigs

Studies were carried out to determine the digestibilities of amino acids (AA) and energy in five sources of rice bran (RB). The sources of RB included two that were not further processed, a defatted, an extruded, and an atypical source of RB consisting mainly of starchy endosperm referred to as polish. Six barrows, average initial body weight 36.5 kg, were fitted with a simple T-cannula at the distal ileum, and fed six diets according to a 6 × 6 Latin square design. The five RB-containing diets contained 53.8% corn, 19.9% soybean meal, and 23.1% RB. The basal diet contained 71.0% corn and 26.3% soybean meal. The dietary allowance was provided at a rate of 4% (wt/wt) of the individual body weight determined at the initiation of each experimental period. Each experimental period comprised 11 d. Following a 7-d adaptation period, faeces were collected for 48 h and ileal digesta for 24 h in two 12-h periods. Chromic oxide was used as the digestibility marker. There was considerable variation in AA digestibilities among the RB samples. By aid of the difference method under the dietary conditions specified, the apparent ileal digestibilities of lysine, methionine, threonine, and tryptophan ranged from 62.6 to 82.2, 61.4 to 76.0, 58.4 to 82.8, and 58.8 to 82.6%, respectively. The digestibilities were lowest in the defatted source of RB and highest in polish. Not including polish of which the total tract energy digestibility was 88.2%, the digestibilities of the other samples ranged from 60.5 to 65.8%. A small proportion of the variation in AA digestibility can be attributed to the content of crude protein, fat and ash in RB. Key words: Amino acids, digestibility, energy, pigs, rice bran

[Clinical and epidemiological study of a series of HIV-infected patients over 50 years old]

INTRODUCTION

The epidemiology of human immunodeficiency virus (HIV) infection has changed in recent years. Cases in persons over the age of 50 have increased, and the most frequent mode of transmission is sexual contact. The objective of this study is to analyse the epidemiological, clinical and evolution characteristics of a clinical series of HIV-infected patients over 50 years old at the time of diagnosis.

METHODS

165 HIV-infected patients over the age of 50, attended at Hospital Clinic (Barcelona) and Corporació Parc Taulí (Sabadell) during the period of 1985 to 2001, were studied.

RESULTS

Among the total, 81% of the patients were men, mean age at the time of diagnosis was 58.5 years, and 81.8% had acquired the disease by sexual contact. The median initial CD4 T cell count was 216 cells/microl. Initial viral load was 1,000-100,000 copies/ml in 45.2% of the patients, whereas 52.3% had > 100,000 copies/ml. At the time of diagnosis, 30.9% had an AIDS-defining disease. The main opportunistic diseases were pulmonary tuberculosis, Kaposi's sarcoma, P. jiroveci (before carinii) pneumonia and non-Hodgkin lymphoma. Mortality due to AIDS was 32.7%.

CONCLUSIONS

Subjects over 50 years old diagnosed with HIV-infection were predominantly men, who acquired the infection by sexual contact. A high percentage of patients were diagnosed with the development of an opportunistic disease.

Effect of phytase supplementation to diets for weanling pigs on the digestibilities of crude protein, amino acids, and energy1,2,3

Four experiments were conducted with weanling pigs fitted with a simple T-cannula at the distal ileum, to determine the effect of phytase supplementation to four diets on the apparent ileal digestibilities (AID) of CP and AA, and the apparent total-tract digestibilities (ATTD) of CP and DE. Phytase (Natuphos, DSM Food Specialties, Delft, The Netherlands) was supplemented at rates of 0, 500 or 1,000 FTU/kg to the four diets. A 20% CP (as-fed basis) corn-soybean meal diet was used in Exp. 1; a 20% CP wheat-soybean meal diet in Exp. 2; a 20% CP wheat-soybean meal-canola meal diet in Exp. 3; and a 19% CP barley-peas-canola meal diet in Exp. 4. In each experiment, six barrows, fitted with a simple T-cannula at the distal ileum, were fed the basal plus phytase-supplemented diets according to a repeated 3 x 3 Latin square design. Each experimental period comprised 14 d. The piglets were at fed 0800 and 2000 daily, equal amounts for each meal, at a daily rate of at least 2.4 times the maintenance requirement for ME. Feces were collected from 0800 on d 8 until 0800 on d 12 of each experimental period. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Chromic oxide was used as the digestibility marker. The average initial and final BW (average of all experiments) were 7.9 and 16.5 kg, respectively. Phytase supplementation did not improve the AID of CP and AA in Exp. 1, 2, and 4; however, there were improvements (P < 0.05) or tendencies (P < 0.10) toward improvements in the AID of CP and AA or the ATTD of CP and the content of DE with phytase supplementation in Exp. 3. These results suggest that the AA response factor to microbial phytase supplementation depends on diet composition.

Alternation of Antiretroviral Drug Regimens for HIV Infection. Efficacy, Safety and Tolerability at Week 96 of the Swatch Study

Introduction

Alternation of antiretroviral drug regimens has been proposed as a novel treatment strategy for HIV infection. However, some concerns persist regarding antiviral efficacy, adherence, toxicity and resistance evolution in the long term.

Methods

A total of 161 antiretroviral-naive HIV-1-infected patients were randomized to receive stavudine/ didanosine/efavirenz (group A) or zidovudine/lamivudine/ nelfinavir (group B) or to alternate between the two regimens every 3 months starting with regimen A (group C). Antiviral efficacy, adherence, safety and tolerability were analysed every 12 weeks.

Results

After 96 weeks, time to virological failure was significantly delayed in the alternating regimen compared with the standards of care regimens. Virological suppression was seen in 46%, 48% and 58% of patients in groups A, B and C, respectively, in the intention-to-treat analysis and in 75%, 76% and 97% in the on-treatment analysis (A vs C: P=0.014; B vs C: P=0.016; A vs B: P=0.849). At the end of the study, 94% of patients in group A and 92% in groups B and C reported an adherence greater than 95%. Alternating therapy was associated with a similar impact on CD4+ counts in comparison with the standards of care regimens, as well as a lower mitochondrial DNA/nuclear DNA (mtDNA/nDNA) ratio decrease in the mitochondrial substudy performed on 37 patients. The frequency and intensity of adverse events in the alternating group decreased during subsequent cycles.

Discussion

Our results favour the hypothesis that proactive therapy switching may delay the accumulation of resistance mutations. Moreover, the alternating regimen was well tolerated and adherence remained comparably high in all treatment groups. The lower mtDNA/nDNA ratio decrease observed in this group may imply a lower impact on mitochondrial toxicity than in standard regimens.

Ileal amino acid digestibility and performance of growing pigs fed wheat-based diets supplemented with xylanase

Two experiments were conducted to determine the effect of supplementation of xylanase to a wheat-based diet on the apparent ileal digestibility (AID) of AA and the performance of growing pigs fed diets limiting in AA. In Exp. 1, eight pigs (average initial BW = 20.5+/-1.2 kg) fitted with a simple T-cannula at the distal ileum, were fed four diets according to a repeated 4 x 4 Latin square design. Diet 1 was a basal diet that contained 97.6% wheat. Diets 2, 3, and 4 were the basal diet supplemented with xylanase at rates of 5,500, 11,000, and 16,500 units of xylanase activity (XU), respectively (as-fed basis). There were linear and quadratic effects (0.062 < P < 0.001) of xylanase supplementation on the AID of CP and most of the AA. The largest increases in AID of CP and AA were obtained when xylanase was supplemented at a rate of 11,000 XU; no further increases were observed with xylanase supplementation at a rate of 16,500 XU. In Exp. 2, 30 pigs (average initial BW 21.4+/-1.8 kg) were randomly allotted to six dietary treatments. Diets 1 to 4 were similar to those used in Exp. 1. Diet 5 was the same as Diet 1, but supplemented with 0.53% lysine, 0.12% threonine, and 0.05% methionine. Diet 6 (positive control diet) was a wheat-soybean meal diet that contained 18.2% CP (as-fed basis). The total contents of lysine, threonine, and methionine were similar for Diets 5 and 6. There was a linear effect of xylanase supplementation on ADG (P = 0.093) and feed:gain ratio (P = 0.089), and a quadratic effect on ADG (P = 0.067) and feed:gain ratio (P = 0.074). But, the greatest response was obtained with the supplementation of 11,000 XU. The supplementation of lysine, threonine, and methionine to Diet 1 increased (P = 0.001) ADG and ADFI and improved (P = 0.01) feed:gain ratio. There was no difference (P = 0.508) in the performance of pigs fed the AA-supplemented or control diet. In conclusion, the supplementation of xylanase to a diet in which wheat provided the sole source of protein and energy improved the AID of AA, ADG, and feed:gain ratio; however, this improvement was very small compared with that obtained with the supplementation of synthetic amino acids.

QT prolongation and Torsades de Pointes in patients infected with human immunodeficiency virus and treated with methadone

Four patients infected with human immunodeficiency virus receiving antiretroviral treatment and high doses of methadone (>200 mg/day) presented with several syncopal episodes. A significant prolongation of the QTc interval was detected in all of them, and in 3 patients, > or =1 episode of Torsades de Pointes was recorded. The sequence of events in these cases suggests that high doses of methadone caused QT prolongation and provided the substrate for syncope and Torsades de Pointes.

Reliability of different techniques to assess marginal defects of Class II restorations in retrieved primary molars: a visual-tactile, SEM, dye penetration and polarized light microscopy study

The aims of the present article were to assess the reliability of different techniques to assess marginal defects in Class II restorations in retrieved primary molars, and to determine the degree of agreement between the various assessment modalities. The material evaluated was comprised of 18 exfoliated primary molars that had been restored 20 to 22 months previously with a resin-modified glass ionomer (Vitremer--7 teeth), a hybridized composite resin (Z100 + Scotchbond Multipurpose--9 teeth), and amalgam (Dispersalloy--2 teeth). No significant differences could be observed between the groups. The majority of the restorations rated A at the buccal and lingual margins, but poor adaptation was disclosed at the cervical margin of the three types of restorations. SEM evaluation revealed that the highest percentage of defects was seen at the cervical margins with no statistically significant difference between the groups. No or minimal leakage was present at the occlusal margins and severe penetration of dye was seen at the cervical margins in all groups. Significantly less demineralization was seen adjacent to the Vitremer and Z100 restorations when compared to the Dispersalloy but no difference was found between the esthetic restorations. Except for the visual tactile examination, small marginal defects could be disclosed by the three assessment techniques (SEM, dye penetration, and polarized light microscopy). A good degree of agreement was observed between the three evaluation techniques.

Place-learning, but not cue-learning training, modifies the hippocampal theta rhythm in rats

Hippocampal theta activity accompanies behaviours such as running, swimming, head movements and spatially orientated responses in the rat. However, whether a relationship between this activity and information processing exists remains unclear. As place-learning depends on hippocampal integrity, whereas cue-learning does not, the hippocampal theta activity underlying each test was evaluated. Local CA1 hippocampal electroencephalograms (EEGs) were recorded over 6 days in a Morris maze for one place-learning test group of rats (n=10) and one cue-learning test group (n=8). The EEG of the corresponding test was taken during waking immobile, searching, and on-platform stages. The relative power (RP) values of EEGs were divided into 4-6.5Hz, 6.5-9.5Hz, and 9.5-12Hz frequency sub-bands. The place-learning training produced a separation of 4-6.5Hz and 6.5-9.5Hz sub-bands in searching and platform stages and a higher activity on the 6.5-9.5Hz sub-band during searching, compared with the basal record, while the cue-learning group did not show differences related either to the training or behavioural stage. As the motor activity and swimming velocity was similar in both groups, the results strongly suggest that the changes observed in theta activity reflect information processing by the hippocampus.

Primary HIV type-1 infection misdiagnosed as Mediterranean spotted fever

The case studies of four patients, two men and two women between the ages of 42 and 54 years, are described. They presented to a hospital emergency department during the summer months with acute fever and exanthema. These are the primary symptoms of Mediterranean spotted fever (MSF), an endemic rickettsial disease in the Mediterranean basin that is seen particularly during the summer. The patients were clinically diagnosed as having MSF, but their diagnoses were not confirmed by serological testing. One patient was diagnosed with primary human immunodeficiency virus type 1 infection (HIV-1) 10 days later. The remaining three patients were diagnosed with HIV infection years later, but it is very likely that they also had primary HIV infection when MSF was presumed. When a patient develops sudden onset of fever and a maculopapular rash that is characteristic of MSF, the possibility of primary HIV-1 infection should be considered.

Recurrent stroke as a manifestation of primary angiitis of the central nervous system in a patient infected with human immunodeficiency virus

CONTEXT

Cerebral vasculitis in patients infected with human immunodeficiency virus (HIV) is usually related to additional or secondary infectious agents other than neoplastic diseases or HIV itself.

OBJECTIVE

To describe a 31-year-old patient infected with HIV who presented with 2 recurrent, acute episodes of neurologic impairment in a 5-month period.

DESIGN

Comparison of clinical and histologic data between the present case and previously published cases.

SETTING

Community hospital.

PATIENT

A 31-year-old, HIV-infected patient with recurrent strokes and chronic lymphocytic meningitis.

INTERVENTION

After ruling out cardiac embolisms and coagulation disorders, the presence of central nervous system vasculitis, probably secondary to an infectious process, was suspected based on the clinical examination and cerebrospinal fluid abnormalities.

RESULTS

Necropsy findings suggest the diagnosis of primary angiitis of the central nervous system, and the only infectious agent that could be found was HIV.

CONCLUSIONS

Histologic studies were compatible with a diagnosis of primary angiitis of the central nervous system, but the pathogenic role of HIV in the genesis of the vasculitic process cannot be elucidated.

[Minimally invasive heart surgery]

Minimally invasive heart surgery encompasses a variety of techniques, each with its own objective (minimal incisions, absence of cardiopulmonary bypass and cost reduction). Postoperative care after such procedures are simpler, with early extubation and shortened hospital stays. A period of close observation in a postoperative intensive care recovery ward is still required.

Neuroprotective effect of melatonin on brain damage induced by acute global cerebral ischemia in cats

BACKGROUND

Melatonin has been proposed as a neuroprotective agent on the basis of its ability to function as a free radical scavenger, provided that lipoperoxidation and other free radical damage induced by reactive oxygen species resulting from cerebral ischemia are relevant pathophysiologic processes of ischemic neuronal damage.

METHODS

The effects of melatonin or vehicle on neurologic deficit scores (Todd scale; maximal deficit score = 100, daily during 7 days after the ischemic episode) and neuronal population of hippocampal CA1-CA4 fields (cresyl violet stain, at the eighth day after the ischemic episode) were evaluated in adult male cats subjected to a 15-min period of acute global cerebral ischemia induced by cardiorespiratory arrest, and in cats subjected to a sham procedure. Continuous intravenous (iv) administration of either melatonin 10 mg/kg/h in 10% ethanol in saline or the vehicle alone (3 mL/kg/h) for 6 h starting 30 min after the end of the period of global cerebral ischemia was used as treatment.

RESULTS

Global cerebral ischemia resulted in a severe loss of neurons in hippocampal CA1-CA4 fields (9, 13, 30 and 28% remaining neurons, respectively) of ischemic vehicle-treated cats in comparison with sham cats (100%). By contrast, remaining neurons in these regions were between 81 and 100% in the ischemic melatonin-treated cats, values that are nonsignificantly different as compared with sham cats. Values of remaining neurons in CA1-CA4 fields in ischemic melatonin-treated cats were significantly higher than those in ischemic vehicle-treated cats. Neurologic deficit scores in ischemic vehicle-treated cats (42-77 at day 1, 6-39 at day 7) were significantly higher than those in ischemic melatonin-treated cats (16-38 at day 1, 0-6 at day 7) on the days after the ischemic episode.

CONCLUSIONS

Overall, the results support the neuroprotective effect of melatonin against the neuronal cerebral damage induced by acute global cerebral ischemia.

Neoplasia of plasma cells with atypical presentation and infection by the human immunodeficiency virus. A presentation of two cases

Neoplasia of plasma cells acquires special clinical characteristics in patients infected by human immunodeficiency virus (HIV). These patients are much younger at the time of diagnosis, and when they are compared with the general population they show an atypical clinical evolution, with a greater frequency of solitary plasmacytomas, less evidence of a monoclonal plasmatic component, or greater aggressiveness of the neoplastic process. This paper provides the most significant data on two patients infected by HIV and diagnosed for plasma cell neoplasia. Recent pathogenetic hypotheses for plasma cell neoplasias that include immune alterations, chronic viral infections, and hyperexpression of cytokines exist in patients infected by HIV, and this could suggest that this type of neoplasia is another malignant haematological process associated with AIDS.

Evidence for a mate-attracting chemosignal in the dwarf African clawed frog Hymenochirus

Many male frogs and toads possess sexually dimorphic skin glands (breeding glands). However, in most anuran species, the functional significance of the glands is unknown. Here we show that the breeding glands of male dwarf African clawed frogs (Hymenochirus sp. ) release a mate-attractant chemosignal. The mate-attractant activity was assessed using a two-choice aquatic Y-maze. Female Hymenochirus were allowed to choose between different treatment waters (e.g., plain water and water housing males) in the upstream arms of the maze, and the females' movements were monitored by computer-linked motion sensors. Females showed a positive chemotaxis to water housing males and to water containing homogenized breeding glands. Females showed no reaction to water housing conspecific females or to water housing breeding gland-ablated males. Additional choice tests demonstrated that females were more attracted to water housing males than to water housing females and to water containing homogenized breeding glands than to water housing breeding gland-ablated males. Males in the maze showed no response to water housing either females or other males, indicating that the attractant is specific for females and is therefore neither a species aggregation signal nor a food-related attractant. These results represent the first experimental demonstration of a mate-attractant function for anuran breeding glands. Because many anuran species possess breeding glands, these results suggest that pheromonal communication could be more widespread among frogs and toads than previously believed.

[Histopathology of sun prurigo]

BACKGROUND

Solar or actinic prurigo (PS) is one of the most common skin diseases observed in our country, particularly in the pediatric age; in our institution it is on the 14 place with a frequency of 1.34%. It represents an abnormal reaction to solar light and in its pathogenesis diverse factors participate, mainly immunogenetical and environmental. Although their clinical characteristics are already specified, the histopathological features are still not well documented.

MATERIAL AND METHODS

We carried out a retrospective and observational study in order to analyze the histopathologic changes in 20 samples of skin coming from 20 pediatric patients with PS; in all of them diagnosis was well established on clinical criteria.

RESULTS

Twenty children with PS of more than one year of evolution, ten of each sex, all mestizos or indigenous inhabitants of Mexico City and vicinity; we identified recent and late lesions, with epidermal and dermal changes, the more conspicuous were: spongiotic papules usually with psoriasiform epidermal hyperplasia, in association with perivascular, superficial and mild lymphocytic infiltrates, usually with few eosinophils, exocytosis of lymphocytes into the epidermis, pigment incontinence and extravasation of erythrocytes.

CONCLUSIONS

The PS is an inflammatory cutaneous disease for which histopathological diagnosis is feasible of being established on skin biopsies of recent or late lesions.

Progesterone: protective effects on the cat hippocampal neuronal damage due to acute global cerebral ischemia

BACKGROUND

Barbiturates, benzodiazepines, and synthetic steroids having anesthetic properties, by enhancing the inhibitory GABAergic neurotransmission to the neuronal circuits of cerebral structures vulnerable to ischemia, reduce the damage induced by this condition. Some endogenous steroids resulting from progesterone (P4) biotransformation in the brain exert GABAergic effects, thus inhibiting neuronal excitability. Hence, P4 administration both before and after an experimentally induced ischemic episode may prevent or decrease the ischemic cerebral damage.

METHODS

Ovariectomized adult cats were treated s.c. with either P4 (10 mg/kg/day) or corn oil during 7 days before and 7 days after being subjected to a period of acute global cerebral ischemia by 15 min of cardiorespiratory arrest followed by 4 min of reanimation. After 14 days of survival, animals were sacrificed and the brains perfused in situ and formalin-fixed for histological examination.

RESULTS

Acute global cerebral ischemia resulted in a severe loss of neurons (54-85%), mainly in CA1 and CA2 subfields of oil-treated cats. Progesterone significantly reduced the neuronal loss in those areas (21-49%).

CONCLUSIONS

Overall results suggest that progesterone exerts protective effects against the neuronal cerebral damage induced by acute global cerebral ischemia.

Recurrent hydrochlorothiazide-induced pulmonary edema

Hydrochlorothiazide-induced pulmonary edema is an unusual but life-threatening adverse reaction. It causes hypoxemia, hypotension, tachycardia, fever, and occasionally electrocardiographic and echocardiographic abnormalities. The mechanism of production is, probably, idiosyncratic.

Characteristic frequency bands of the cortico-frontal EEG during the sexual interaction of the male rat as a result of factorial analysis

The electrocorticogram (ECoG) from the prefrontal cortex was simultaneously recorded with the accelerometric signals of pelvic thrusting performed by male rats during sexual behavior. The changes in the prefrontal ECoG were precisely correlated in time with well defined elements of male rat copulation. Principal component analysis allowed to identify three distinct bands of frequencies in the frontal ECoG: the absolute power (AP) of the 4-16 Hz band was increased in the 500-ms periods before, during, and after the execution of pelvic thrusting in mount, intromission and ejaculation responses; the AP of the 18-24 Hz band was selectively increased during the execution of pelvic thrusting at the three copulatory responses, whereas the AP of the 26-32 Hz band was increased only during the pelvic moments of mount and intromission responses. These results show that the electroencephalographic activity of the prefrontal cortex of the male rat is related to the performance of sexual behavior, supporting the concept that this cortical area is involved in the organization of sequential behaviors, as sexual behavior.

Computer programs to analyze brain electrical activity during copulatory pelvic thrusting in male rats

Two microcomputer programs have been developed to simultaneously record and analyze the brain electrical activity: multiple unit activity (MUA) and electroencephalogram (EEG), and the accelerometric signals generated in relation to the pelvic thrusting that performs the male rat during the copulatory responses of mount, intromission, and ejaculation. CAPTUMUL is a program allowing the on line capture of the different signals and the further off line delimitation of the brain signals occurring in exact temporal relation with the accelerometric record of motor responses. The ANAMUA program allows the off line analysis of the neuronal firing rate in MUA records at different discrimination levels according to the amplitude of the neuronal spikes, and compare these data in various behavioral situations. The use of these programs provides a way of correlating in time the changes of brain electrical activity occurring in animals in free-movement with the brief motor events of copulation as well as with other behaviors (i.e., genital grooming, sniffing, running, walking). Advantages of this software include the recording of sequential events, a better and rapid handling of data and a reliable method to analyze the MUA with different discrimination levels according to the amplitude of the neuronal spikes.

Investigation of Cr:Tm:Er:YAG laser crystals in a resonator with various degrees of spectral selectivity

It has been established that Tm(3+) ions do not prevent multiple-wavelength oscillation in Cr:Tm:Er:YAG laser crystals inserted inside of the completely nonselective mirror resonator. The output mirror spectral selectivity needed for single-wavelength oscillation at 2.697 mum for a considerable excess of pumping energy over the threshold has been determined experimentally. It has been shown that Tm(3+) optimum concentration in the crystals could be determined correctly in the described resonator scheme.

Immunological and virological activity of zalcitabine and zidovudine in combination in HIV-positive people with CD4 cell counts of between 200-500 cells/mm3

We evaluated the effect of combination therapy with zidovudine (AZT) plus zalcitabine (ddC) in human immunodeficiency virus type 1 (HIV-1)-infected patients who had not previously received antiretroviral treatment ('naive' patients). The immunological and virological parameters evaluated were CD4 cell count, syncytium-inducing (SI) viral phenotype and plasma HIV-1 RNA copies/ml (HIV viral load). A total of 75 patients entered the study, with CD4 cell counts between 200 and 500 cells/mm3. All received zidovudine (200 mg) plus zalcitabine (0.75 mg) three times daily for 24 weeks. Treatment was well tolerated. However, four patients presented with anaemia (haemoglobin < 10.0 g/dl) and one patient had both anaemia and neutropenia (0.8 x 10(9) neutrophils/l). Combination therapy with zidovudine plus zalcitabine resulted in a pronounced improvement of virological and immunological markers. Approximately 25% of patients achieved undetectable plasma HIV RNA levels (< 200 copies/ml) at week 24. At the end of the study (24 weeks) a significant reduction (> 0.5 log) of plasma HIV RNA was observed in approximately 70% of patients and in 50% an even greater decrease (> 1 log) was achieved. The most significant decrease in mean plasma HIV RNA levels was observed at week 4, whereas the highest increase in CD4 cell count was found at week 24. Approximately 80% of patients who showed baseline plasma HIV RNA levels below 20000 copies/ml had less than 5000 copies/ml at week 24. The plasma HIV RNA reduction observed at week 4 was significantly maintained at week 24. Therefore, we can rapidly select those who will not respond to therapy and adjust the treatment after a short interval. Our study supports the idea of early therapy because all patients who reached undetectable levels of plasma HIV RNA at week 24 had at baseline a median plasma HIV RNA load of 2560 copies/ml. In conclusion, zidovudine in combination with zalcitabine was well tolerated in the majority of patients and led to a significant reduction in plasma HIV RNA copies in most of the patients with initial viraemia lower than 20000 copies/ml.

Subcortical multiple unit activity changes during rat male sexual behavior

Multiple unit activity (MUA) was recorded from the ventral tegmental area (VTA) and mesencephalic locomotor region (MLR) during copulatory behavior of freely moving male rats. Simultaneous accelerometric recordings of the copulatory pelvic thrusting performed by the male rat were taken to precisely correlate in time the changes in MUA with well defined elements of copulation. The baseline MUA firing rates recorded in the quiet-alert condition in the VTA and in the MLR were significantly increased during pursuit of the female by the male; significantly higher MUA firing rates were found in the VTA at the 500 ms periods before and during the execution of pelvic thrusting in mount, intromission, and ejaculation responses as compared to the baseline, and returned to this value when these responses ended. The maximum MUA firing rate in the MLR was obtained during the execution of pelvic thrusting in each copulatory response, and it remained significantly elevated, as compared to the baseline, after thrusting and at the postintromission and postejaculatory genital grooming, then decreasing to basal values at the initial part of the postejaculatory interval. The fact that the highest changes in MUA were related to pelvic thrusting suggests a major participation of both structures in the execution of motor copulatory responses.

Serum vitamin A, vitamin E, and beta-carotene levels in preeclamptic women in northern nigeria

We compared the serum levels of beta-carotene, vitamin A (retinol), and vitamin E (alpha-tocopherol) in healthy pregnant women and their counterparts who exhibited the signs and symptoms of preeclampsia or eclampsia, including: systolic blood pressure greater than 160 mm Hg, edema, and proteinuria. The study was conducted in the cities of Maiduguri and Bauchi, which are located in the semi-arid northeastern region of Nigeria. Most of the pregnant subjects: (1) were teenagers, though they ranged in age from 14 to 25 years; (2) had 2 or fewer prior pregnancies; and (3) were predominantly of the Muslim faith and members of the Hausa, Fulani, or Kanuri ethnic groups. Few of the women had received prenatal care. Serum levels of vitamins A and E and betacarotene were quantified using high pressure liquid chromatography. The serum vitamin A levels of the 9 preeclamptic women (15.3 mg/dL) and the 7 eclamptic women (8.3 mg/dL) were significantly reduced (p < 0.01) relative to the serum vitamin A levels of healthy women in the third trimester (24.2 mg/dL). For the healthy pregnant controls, the levels of vitamins A and E and beta-carotene were relatively constant throughout pregnancy. The mean serum beta-carotene levels for both the preeclamptic and eclamptic groups of subjects were half as high as those of healthy control women in the third trimester (p = 0.004). The serum vitamin E levels of the preeclamptic and eclamptic women were 15% and 30% lower, respectively, than those of the corresponding controls (p < 0.01). The serum levels of these three lipids in the healthy pregnant and non-pregnant women we studied are similar to values reported by others for North American and European women of childbearing age. These results support the hypothesis that preeclampsia-eclampsia deplete natural lipid antioxidants and suggest that the reduced levels of vitamin A in such women experiencing hypertension of pregnancy, if they happen to be infected with the HIV-1 virus, may place them at increased risk for mother-child transmission of the virus.

Breast cancer cytogenetics: a review and proposal for clinical application

Cytogenetic analyses of hematological neoplasms have proved to be relevant in the diagnosis, treatment, and prognosis of afflicted patients. Breast cancer (BC) cytogenetics is expected to contribute in the same fashion. Literature has shown that clone-specific chromosomal changes do occur in BC, yet, their clinical significance is unknown. Most of the studies have been conducted on patients with advanced stage tumor. Karyotypic analyses of the few reported cases from stage I BC tumors revealed a higher frequency of single clonal abnormalities. This work describes an ongoing BC cytogenic study on samples from stage I tumors to enhance and clarify this observation. Included as control are chromosomal analyses of peripheral blood and peritumoral normal tissue samples of these patients, which might provide information regarding predisposing cytogenetic aberrations. Non-random chromosomal abnormalities in BC include involvement of chromosomes 1, 3, 6, 11, 16, and 17. Three groups of non-random chromosomal alterations, ranging from specific abnormalities, partial monosomies, and secondary changes (eg, numerical loss of chromosomes) are described. Survival appears to be more favorable in patients without complex karyotypes. A better understanding of the clinical and etiologic implications of BC is expected to emerge from continued assessment of breast tumor cytogenetics.

[Changes in the cell cycle in breast cancer]

Recent advances in the mechanisms of oncogenesis have revealed a close relationship between the cell cycle and apoptosis. The cell cycle goes through a series of kinases and fosfatases activities that enhance the cyclins. In the mammalian cells, the kinases CDK4/6, CDK2, CDK2 and p34 are linked to the cyclins D, E, A, and B When the cell goes from the phase G1 toward mitosis. When the DNA is altered by intrinsic or extrinsic factors, the control checkpoints should stop the cycle in order to repair the damage. If the DNA cannot be repaired, apoptosis is induced. In cancer, the checkpoints do not function and the unstable genome of the cancer cell is repaired. Some of these changes occur in cancer of the breast and are discussed in this review.

[Winter epidemic of carbon monoxide poisoning in Badia]

OBJECTIVE

To find the incidence, morbidity and possible causes of the acute carbon monoxide poisonings (ACMP) which occurred in Badia between january 1992 and june 1993.

DESIGN

A longitudinal, retrospective study.

PATIENTS

Every Badia resident discharged from the Hospital Consortium of Parc Taulí, Sabadell with a diagnosis of ACMP and/or from Barcelona's Red Cross Hospital (RCH) after hyperbaric treatment was considered.

MEASUREMENTS AND RESULTS

Cases were identified using the hospital discharge records from Parc Taulí and the RCH. A systematic review of the primary care clinical records was undertaken. The causes of the poisoning were investigated by a technical committee and through the gas company carrying out inspections of dwellings in 1993. The incidence of ACMP was 76.5 per 100,000 inhabitants in 1992 and 109.4 per 100,000 in the first half of 1993. 94% of the 34 cases occurred in December, January, February and March. 50% of those affected were under 17. The number of cases per household varied between 2 and 5 people. The most common underlying cause was the existence of defects in the conduits taking fumes away from gas heaters. The gas review detected defects in installation in 54% of dwellings.

CONCLUSIONS

ACMP is a common and serious problem in our environment. The underlying causes and the high number of dwellings at risk have suggested a need for information campaigns in the community.

Cloning of a cDNA encoding ATP sulfurylase from Arabidopsis thaliana by functional expression in Saccharomyces cerevisiae

ATP sulfurylase, the first enzyme in the sulfate assimilation pathway of plants, catalyzes the formation of adenosine phosphosulfate from ATP and sulfate. Here we report the cloning of a cDNA encoding ATP sulfurylase (APS1) from Arabidopsis thaliana. APS1 was isolated by its ability to alleviate the methionine requirement of an ATP sulfurylase mutant strain of Saccharomyces cerevisiae (yeast). Expression of APS1 correlated with the presence of ATP sulfurylase enzyme activity in cell extracts. APS1 is a 1748-bp cDNA with an open reading frame predicted to encode a 463-amino acid, 51,372-D protein. The predicted amino acid sequence of APS1 is similar to ATP sulfurylase of S. cerevisiae, with which it is 25% identical. Two lines of evidence indicate that APS1 encodes a chloroplast form of ATP sulfurylase. Its predicted amino-terminal sequence resembles a chloroplast transit peptide; and the APS1 polypeptide, synthesized in vitro, is capable of entering isolated intact chloroplasts. Several genomic DNA fragments that hybridize with the APS1 probe were identified. The APS1 cDNA hybridizes to three species of mRNA in leaves (1.85, 1.60, and 1.20 kb) and to a single species of mRNA in roots (1.85 kb).

Effects of nimodipine on multiunit activity of several brain structures following acute global cerebral ischemia-anoxia in cats

The effects of nimodipine, a 1,4-dihydropyridine calcium channel blocker, on multiunit activity (MUA) of several brain structures were investigated in cats during 6 h immediately following acute global cerebral ischemia-anoxia induced by a 10 min cardiorespiratory arrest (CRA), as well as in cats exposed to sham procedures corresponding to CRA. Four groups of cats were studied: 1) CRA and continuous administration of nimodipine, 1 microgram/kg/min iv during 6 h; 2) CRA and continuous administration of vehicle; 3) sham and continuous administration of nimodipine as in group 1; 4) sham and vehicle as in group 2. MUA and electroencephalogram disappeared during ischemia-anoxia; their progressive recovery occurred throughout the hours following CRA, although 6 h after CRA MUA was still lower than its control prearrest values in all the recorded subcortical structures. Delta-like waves, isolated spikes, and bursts of fast EEG waves occurred during the recovery of EEG activity. Nimodipine inhibited the otherwise increasing MUA in mesencephalic reticular formation, hippocampus and putamen, but not in ventromedial hypothalamus, during the hours following acute global cerebral ischemia-anoxia. Absence of isolated spikes and bursts of fast EEG activity was noted in the EEG of CRA-, nimodipine-treated cats. Nimodipine significantly reduced MUA in hippocampus but not in other cerebral structures in cats of the sham treated group. The results suggest the involvement of 1,4 dihydropyridine sensitive calcium channels in the cellular mechanisms related to neuronal activity after cerebral ischemia-anoxia, and the possible relationship between the effects of nimodipine on MUA and better functional conditions of the central nervous system after acute global cerebral ischemia-anoxia.

Modifications of acoustic habituation by interruption of visual input in quipazine treated cats

The influence of interruption of the visual input on acoustic habituation was studied in cats before and following the administration of quipazine, 3 mg/kg iv. The characteristics of acoustic habituation were analyzed through the magnitude and temporal course of multiunit activity (MUA) responses elicited in the mesencephalic reticular formation (MRF) by repetitive acoustic stimuli (70 db, 50 Hz trains of 2 sec duration) in 6 freely moving cats with cortical electrodes over the parietal cortex and bipolar electrodes chronically implanted in MRF and basolateral amygdala (AMN). The cats were submitted to repetitive acoustic stimulation during one 30 min period before, and three 30 min periods after drug administration in the following conditions: a) with unmasked eyes; b) with masked eyes by means of dark contact lenses. Persistent attentive behavior, catatonic attitudes, hypersynchronous (6 Hz, 100-150 microV) EEG activity and significant increase of spontaneous MUA in FRM and AMN were induced by quipazine both in the cats tested with unmasked and with masked eyes. This increase of MUA was higher immediately following drug administration and progressively decreased, although MUA values remained significantly higher than controls 110 min after quipazine administration. Acoustic habituation, evidenced through the progressive decrease of MUA responses of MRF to acoustic stimuli, was observed before quipazine administration when the cats were tested with unmasked and with masked eyes; as well as in cats tested with unmasked eyes following drug administration. However, the MUA responses to acoustic stimuli did not decrease in cats with masked eyes during acoustic stimulation periods 0-30 min and 40-70 min after quipazine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain injury following cardiorespiratory arrest in cats. Effects of alphaxalone-alphadolone

The effects of alphaxalone-alphadolone acetate (27.07 microM/kg-7.68 microM/kg) on neurologic injury following acute cerebral ischemia induced by an 8 min cardiorespiratory arrest (CRA) were investigated in cats through the analysis of neurological deficit scores and brain electrical activity; i.e., electroencephalogram (EEG) from parieto-occipital cortices and EEG and multiunit activity (MUA) from mesencephalic reticular formation (MRF). The CRA resulted from electrically induced cardiac arrest and stopping of mechanical ventilation in paralyzed cats which were successfully resuscitated within the immediate 4 min after the end of CRA. Two groups of cats were studied: I. Untreated, which received saline iv; II. Treated, which received alphaxalone-alphadolone acetate iv, 7-9 min after the end of CRA. Neuromuscular blockade and mechanical ventilation were maintained until 8 h following the CRA; then the cats were allowed to recover spontaneous respiratory activity. EEG phenomena were different in untreated and treated cats during this immediate post-arrest period. The former showed rhythmic bursts of fast (12-20 Hz) EEG activity at 1-2 sec intervals from 15-20 min until 3-4 h after the CRA, abundant spikes and delta-like waves. By contrast, administration of alphaxalone-alphadolone acetate resulted in burst suppression EEG pattern during 1 h. Progressive recovery of background EEG activity occurred afterwards. MUA from MRF disappeared during the CRA, however 6 h later the mean MUA frequency in untreated cats ranged between 32-46% and in treated cats 18-27% of their control mean frequencies during paradoxical sleep (100%). Daily electrographic records were performed in all the cats during quiet attentive behavior at each of the five days following the CRA. Significant differences were found in the frequency distributions of MUA from MRF (1st day, p less than 0.01; 5th day, p less than 0.01) as well as in the cortical EEG waves (1st day, p less than 0.01; 5th day, p less than 0.05) before and after the CRA in the untreated group. A wide dispersion of MUA values, and increased proportions of delta and theta-like waves and spindle bursts, besides a significantly high (p less than 0.001) number of spikes occurred in these EEG records the days following the CRA. The frequency distributions of MUA and EEG did not significantly differ before and after the CRA in the treated group; however, a significantly high (p less than 0.05) number of spikes was found in treated cats following the CRA.(ABSTRACT TRUNCATED AT 400 WORDS)

Pulfrich refractometer for 1-D gradients

A refractometer based on the critical angle condition was constructed and found useful for determining 1-D distributions of refractive index. The method is particularly convenient when transient liquids are tested, although it is applicable to solid samples. The device is simple and straightforward in its use, allowing realtime measurements with no additional optical system. The sensitivity can be changed with the size of the apparatus.