Serological and bacteriological observations on experimental infection with Salmonella hadar in chickens

Over the past 3 years the frequency of Salmonella hadar infections has increased in Belgium in both poultry and humans. Therefore, the course of infection with S. hadar in poultry was investigated. One day-old and 4 week-old specific pathogen-free chickens were orally infected with one of two S. hadar strains, SH1 or SH2. Mortality was 6% (SH1) and 17% (SH2) in birds infected at 1 day-old. Chickens infected at 1 day-old with SH2 showed a mild diarrhoea. The S. hadar faecal excretion in birds infected at 1 day-old remained high throughout the experiment until 12 weeks post-inoculation (pi). Faecal excretion was lower in older birds. Antibodies to S. hadar were observed from 2 weeks pi (SH2, infected at 1 day-old) or 4 weeks pi (SH1, both groups; SH2, chickens infected at 4 weeks of age). The percentage of chickens with antibodies was higher after infection at 1 day-old than after infection at 4 weeks of age. In a second experiment 1 day-old chicks were infected with SH1 and autopsied at regular intervals until 42 days pi. SH1 was isolated from the caeca from 3 h pi onwards and from the liver and spleen from 18 h until 14 days pi. Serous typhlitis and omphalitis were the main lesions. The number of macrophages in the lamina propria of the caecal tonsils was slightly increased from 18 h until 2 weeks pi. In the liver, inflammation was observed in the portal triads and in the sinusoids. This study indicates that infections with S. hadar lead to intense colonisation of the gut and extensive faecal shedding. It may also cause invasive infections in 1 day-old chickens.     

Changes in prolactin secretion in postnatal rats and effect of neonatal thyroidectomy

Rats were inoculated intraperitoneally (i.p.) or intracerebrally (i.c.) with 1 x 10(4) plaque forming units (PFU)/animal of the D variant of encephalomyocarditis virus (EMC-D) at 2, 4, 7, 14, 28 or 56 days of age for virological and histopathological examination. In the i.p.-inoculation study, neither viral replication nor lesions were detected in the animals inoculated at 28 and 56 days of age. In the animals inoculated when younger than 14 days of age, lesions were restricted to the brain although viral replication was detected in the brain, heart and pancreas. The brain lesions were characterized by acute meningoencephalitis with neuronal necrosis in the cerebral cortex, hippocampus and thalamus, and viral RNA was detected in degenerated and/or intact neurons. In the i.c.-inoculation study, similar age-related changes in susceptibility of rat brain to EMC-D infection were observed, but a minor difference was that viral replication and lesions were still detected in the hippocampus of some animals inoculated at 28 days of age. These results suggest that an age-related decrease in the susceptibility of rat brain to EMC virus infection may reflect an age-related change in the susceptibility of neurons themselves as well as in maturation of the immune system.     

Cryptosporidium and concurrent infections with other major enterophatogens in 1 to 30-day-old diarrheic dairy calves in central Spain

Faeces samples from 218, 1 to 30-day-old, diarrheic dairy calves in 65 dairy herds were screened for the presence of Cryptosporidium and concurrent infections with rotavirus, coronavirus, F5 Escherichia coli and Salmonella spp. Calves were grouped according to their age as follows: 1-7, 8-14, 15-21 and 22-30 days. Cryptosporidium infection was detected in 43.8%, 71.9%, 63.2% and 6.9% of the calves in the respective age groups. Significant differences in the detection rate of Cryptosporidium were found between the age group 22-30 days and all other age groups, and between the age group 1-7 days and the age groups 8-14 days and 15-21 days. Cryptosporidium was the only enteropathogen detected in 60 of the 114 (52.6%) diarrheic calves. Concurrent infections with other enteropathogen(s) were detected in 64.3%, 46.3%, 39.5% and 0% of the Cryptosporidium-infected calves in the age groups 1-7, 8-14, 15-21 and 22-30 days, respectively. A significant age-associated decrease in the detection rate of mixed infections (p < 0.05) was found. The detection rates of the other enteropathogens considered in calves with Cryptosporidium infection were 87% for rotavirus, 11.1% for coronavirus, 27.8% for F5+ E. coli and 1.8% for Salmonella.     

Effect of photoperiod upon age and maintenance of sexual development in female Coturnix coturnix japonica

Coturnix kept in a 14L:10D photoperiod from hatch began to lay their first eggs at a mean age of 42.8 days (range 38-55). Approximately 2/3 of Coturnix held from hatch in photoperiods of 6L:16D light were laying at 165 days of age. Mean age at first egg was 112.7 days (range 68-162 days) in 8L:16D and 130.8 days (range 117-158 days) in 6L:18D photoperiod. Coturnix transferred from a non-stimulatory (8L:16D) photoperiod to a stimulatory one (14L:10D or 24L) begun laying in 15-20 days if less than 140 days old, and in about 5 days if greater than 140 days old, when trasferred. Birds which has spontaneously begun to lay in an 8L:16D photoperiod did not stop laying when the photoperiod was reduced to 6L:18D. Those which began laying under 14L:10D photoperiod ceased laying in about 15 days if 89 or fewer days old when switched to 8L:16D, or in about 6 days if 140 or more days old. Those switched from 14L:10D to 6L:18D ceased laying in about 13 days when 76 days old, and 7 days when 89 days old.     

The effect of vaccination against Mycoplasma hypopneumoniae in pig herds with a continuous production system

An inactivated Mycoplasma hyopneumoniae vaccine was evaluated in five pig herds clinically infected with enzootic pneumonia and practising a continuous production system in the growing/finishing unit. In each herd, a vaccinated and control group of approximately 47 pigs each were individually monitored from birth until slaughter. Vaccinated pigs received the first dose at about 1 week of age and the second approximately 3 weeks later. During all production stages, an equal number of vaccinated and control pigs was present in the same pen. Both groups were compared with respect to zootechnical parameters (major variables) and by means of serological, pathological, and bacteriological parameters (ancillary variables). Daily weight gain was improved by 14 gr/day during the period from 8 days of age until slaughter (P = 0.0486) and by 25 gr/day during the growing/finishing period (P = 0.0067). Mortality rate, and the costs for curative medication were not significantly improved by vaccination. The results of the ancillary variables are presented and discussed.     

Closure of the ductus venosus in premature infants: findings on real-time gray-scale, color-flow Doppler, and duplex Doppler sonography

OBJECTIVE: Our objective was to use gray-scale, color-flow, and duplex Doppler sonography to study the anatomy, flow pattern, and time of closure of the ductus venosus in healthy premature infants. SUBJECTS AND METHODS: We prospectively examined the ductus venosus in 130 premature infants whom we divided into two groups: Group I comprised 27 neonates of gestational age 28-32 weeks, and group II comprised 103 neonates of gestational age 33-36 weeks. Neonates who had undergone umbilical vessel manipulation were excluded from the study. All examinations included gray-scale, color-flow, and duplex Doppler sonography. Patency, length, color flow, and Doppler characteristics of the ductus venosus were recorded. Neonates were examined 1-2 days after birth, 6-7 days after birth, and subsequently every 3-4 days until ductus closure was observed. The time of closure of the ductus for the two groups was compared using the chi-square test. RESULTS: The ductus venosus was patent during the initial examination in 128 of the 130 neonates. Doppler waveform was venous with little variation in velocity. Ductus length slightly exceeded 1 cm in both groups. We found a statistically significant difference in the percentage of infants having a patent ductus venosus after the initial examination: At 1 week after birth, ductus patency was shown in 85% of the infants in group I and in 56% of the infants in group II; at 2 weeks, the respective percentages were 42% and 14%; and at 3 weeks, 27% and 0%. CONCLUSION: The ductus venosus is patent 1-2 days after birth in virtually all premature infants. From 6 days after birth and onward, a significantly greater percentage of smaller premature infants (i.e., 28-32 weeks' gestational age) have a patent ductus venosus than do larger premature infants (i.e., 33-36 weeks' gestational age).     

Neuroanatomical changes in the rat bladder after bladder outlet obstruction

OBJECTIVE: To evaluate the perinatal and 2-year outcomes in pregnancies complicated by preterm premature rupture of membranes (PROM) during the second trimester. METHODS: Fifty-three consecutive singleton pregnancies with PROM at 14 to 28 weeks of gestation were studied retrospectively. Management goals were to prolong the pregnancies to 32 weeks through expectant management and to avoid fetal compromise through closer monitoring and active intervention, when necessary, after 23 weeks. Outcome of the surviving infants was based on neurologic, audiometric, and ophthalmologic examinations at 2 years of corrected age. RESULTS: Rupture of membranes occurred at 14-19 weeks (mean 17.4 weeks) in 10 women, at 20-25 weeks (mean 24.0 weeks) in 24, and at 26-28 weeks (mean 27.6 weeks) in 19. The median latency periods to delivery were 72 days, 12 days, and 10 days when rupture of membranes occurred at 14-19 weeks, 20-25 weeks, and 26-28 weeks, respectively. The overall incidence of chorioamnionitis was 28%. There were no fetal deaths and nine neonatal deaths. When rupture of membranes occurred at 14-19 weeks, 20-25 weeks, and 26-28 weeks, the perinatal survival rates were 40%, 92%, and, 100%, respectively. Pulmonary hypoplasia accounted for seven deaths. Of the live-born infants, 81% were alive at 2 years of corrected age. Survival without major impairment was observed in 75%, 80%, and 100% of the survivors when rupture of membranes occurred at 14-19 weeks, 20-25 weeks, and 26-28 weeks, respectively. CONCLUSION: Expectant management of second-trimester PROM offers better perinatal and long-term survival than previously thought.     

Prospective study of neonatal genital mycoplasma colonization and infection

Genital mycoplasmas have been implicated in different neonatal diseases as pneumonia, sepsis and meningitis. This prospective study was conducted to specify their role in these diseases. POPULATION AND METHODS--A pharyngeal or tracheal swab specimen for mycoplasmas culture was obtained from 100 infants admitted consecutively to the Neonatal Care Unit (NCU) during the first 24 hours of life. Mycoplasma culture of blood and cerebrospinal fluid was also performed. Pharyngeal and/or tracheal specimens were collected again on days 5, 15 and 28 if the child was still in the NCU. Mycoplasma hominis (Mh) and Ureaplasma urealyticum (Uu) were identified by culture in a modified Hayflick's medium. RESULTS--Three-hundred and ten pharyngeal or tracheal swabs were obtained (100 on day 0, 89 on day 5, 72 on day 15 and 49 on day 28). Twenty-one infants had one or more positive swabs in the first five days of life (20 on day 0 and one on day 5); those forming the "Myco+" group and the others forming the "Myco-" group. Uu was isolated alone from 20 infants, associated with Mh from one. Both groups were similar for gestational age, birth weight, maternal fever during labor, prolonged rupture of the fetal membranes or chorioamnionitis and for the incidence of acute respiratory distress. There was a statistically significant difference for the route of delivery (chi 2 < 0.02). One blood culture (from 92 performed) was positive for Uu and another positive for Uu and Mh. Both children were cured without any specific mycoplasmacidal therapy. Three children had probable Uu infection and were also cured without specific therapy. CONCLUSIONS--A pharyngeal colonization with genital mycoplasmas is common in the first days of life (21%) but our data do not allow us to conclude that they are accountable for newborn infections.     

Systematic review and meta-analysis of early postnatal dexamethasone for prevention of chronic lung disease

AIM: To review systematically the evidence to determine whether dexamethasone treatment of very low birthweight infants begun within 14 days of age prevents chronic lung disease (CLD) without clinically significant side effects. METHODS: Randomised controlled trials of dexamethasone started within this time frame were identified through a search of electronic databases, proceedings of scientific meetings, and personal files. Meta-analyses using event rate ratio (ERR), event rate difference (ERD), and if significant, numbers needed to treat (NNT) for benefits and numbers needed to harm (NNH) for adverse effects were calculated. Weighted mean difference were used for continuous variables. Three prespecified subgroup analyses were performed for; (i) dexamethasone begun within 36 hours (hours) of birth; (ii) dexamethasone initiated between 7-14 days of age; or (iii) if surfactant treatment was used. RESULTS: Ten studies were included in the review; six where dexamethasone was initiated within 36 hours of age, four studies for dexamethasone started between 7 and 14 days and six studies using surfactant. Mortality ERR and NNT with 95% confidence intervals for dexamethasone initiated at 7-14 days of age were 0.35 (0.16, 0.74) and 8 (4, 30). ERRs and NNTs for CLD at 28 days and 36 weeks of postmenstrual age were 0.71 (0.61, 0.84), 8 (5, 17), and 0.57 (0.44, 0.76), 10 (6, 23) in the overall analyses. When dexamethasone was started at 7 to 14 days of age ERR and NNT for CLD at 36 weeks were 0.63 (0.47, 0.85) and 3 (2, 9). Clinically significant side effects included increased risk of hypertension, hyperglycaemia, and increased time to regain birthweight. CONCLUSIONS: These meta-analyses show a significant reduction in risk of CLD at 28 days and 36 weeks of postmenstrual age. In the subgroup where dexamethasone was started between 7 and 14 days of age mortality was significantly reduced. Caution is warranted in the routine use of dexamethasone because of lack of data on long term neurodevelopmental outcomes.     

Pharmacokinetic study in rats after single intravenous and oral administrations of [14C]-ITF-296

Fifteen mycoplasma-free chickens were contact exposed to five chickens that had been experimentally infected with one of three different strains (two field strains and one laboratory strain) of Mycoplasma synoviae (MS). Culture and polymerase chain reaction (PCR) were positive by 3 days postinoculation (PI) in the experimentally infected birds. Lateral transmission was found by 7-14 days postexposure. Positive serum plate agglutination (SPA) results were detected 3-4 wk after positive culture and/or PCR in individual birds. By 42 days PI, all the birds in the groups exposed to field strain K1858 or K3344 had become infected as determined by culture and PCR, whereas only half of the birds in the group exposed to laboratory strain WUV1853 had become infected. Because of the unanticipated lack of seroconversion to hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) in infected chickens, the study was extended. Each group was split into two groups of 10 birds each, one of which was vaccinated with a live B1/LaSota Newcastle disease (ND) vaccine virus to determine if a viral respiratory challenge might incite a stronger antibody response to the mycoplasma infection. All the birds were tested for seroconversion 14 and 21 days later. Of the birds vaccinated for ND, a slightly greater number were MS positive by SPA than the nonvaccinated birds. This effect was not present 21 days after vaccination, and there was no significant difference in the MS HI results from these groups, suggesting that the viral respiratory infection had little direct impact on seroconversion. The virulent field strain (K3344) elicited a stronger MS antibody response than the other strains. All results from the MS ELISA were negative in all groups through 9 wk. Positive results from PCR analysis correlated well with culture results, whereas serologic tests did not detect MS infection for several weeks. Monitoring programs solely dependent on seroconversion may be inadequate for diagnosis and control of mycoplasma infections.     

The association between selected metabolic parameters and left abomasal displacement in dairy cows

The objective of this study was to examine the association between selected metabolic parameters and subsequent left displaced abomasum (LDA) diagnosis in dairy cows. Forty-four LDA cows sampled in the third week ante partum (a.p.) which was at a median of 34 days prior to LDA diagnosis, 36 LDA cows sampled in the first week post partum (p.p.) which was at a median of 14 days prior and 28 LDA cows sampled in the second week p.p., which was at a median of 9 days prior to LDA diagnosis were used. Each case was matched to 3 controls by herd and calving date. Data were available from a large field study. Aspartate-aminotransferase (AST) activity, the concentrations of beta-hydroxybutyrate (BHB), glucose, calcium and urea in blood, and the body condition score (BCS) were studied. Logistic regression was used to analyse the association between these parameters and subsequent LDA, adjusting for the effects of parity and pretreatment. A separate model was used for each sampling week and each parameter. In the third week a.p. none of the parameters were significantly associated with LDA. AST and BHB sampled in the first week p.p. and in the second week p.p. were significantly associated with LDA diagnosis. The higher the AST and BHB, the higher the odds of being diagnosed subsequently with LDA. The lower glucose and Ca in the second week p.p. the higher the odds of subsequent LDA diagnosis. Urea and BCS were not significantly associated with LDA in any of the weeks examined. We conclude that AST and BHB in the first and second week p.p. might be used as tests for subsequent LDA. Glucose, calcium, urea and body condition were either not significantly associated with LDA or significantly associated only in the second week p.p.; this may limit their use as tests for LDA.     

Long-term sequential determination of behavioral ontogeny of 5-HT1A and 5-HT2 receptor functions in the rat

Activation of 5-hydroxytryptamine1A (5-HT1A) receptors in rats produces hypothermia and a number of behaviors [hindleg abduction (HLA), lateral head-weaving (LHW), forepaw treading (FPT), flat body posture (FBP), rollover (RO), tremor (T), and straub tail (ST)] known collectively as the serotonin syndrome (SS). Stimulation of 5-HT2A receptors produces wet-dog shakes (WDS), whereas 5-HT2C sites induce back muscle contraction (BMC). We investigated the functional ontogeny of the cited receptors in rat pups on postnatal days (PD) 7, 14, 18, 22, 28, 35, 60, and 120 by using (1) the 5-HT1A agonist 8-hydroxy-2-dipropylaminotetralin (0, 1.25, and 5 mg/kg) to induce the SS and hypothermia and (2) the 5-HT2A/C agonist (+/-)-1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane (0, 0.5, and 4 mg/kg) to produce both WDS and BMC. The age of onset for most symptoms of SS [FBP, HLA, RO, and T] was the first week of life. They attained maximal intensities at ages 7 to 14 days, after which their maxima either reduced or dissipated to zero. Per contra, the onset of LHW and FPT required 14 to 18 days, and their maxima developed later. The onset of (+/-)-1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane-induced WDS occurred after PD 14, and by PD 18, it reached its maximal intensity, which persisted up to PD 60, after which it declined. The onset of BMC was evident on PD 28 and attained its maximal frequency at ages 90 to 120 days. The results show that different components of SS appear within 14 days of birth, but they mature differentially, whereas the hypothermic effect of 5-HT1A receptors remains relatively constant during aging. The times of onset and maturation of WDS were intermediate (between the second and third weeks of life), whereas BMC required 1 to 2 months for its appearance and maturation.     

Dynamic study on relationship between serum SEAIC level and hepatic pathological changes in mice infected with Schistosoma japonicum

Using purified rabbit polyclonal antibodies to SEA, avidin-biotin system and capture ELISA technique, we observed the dynamic changes in the level of the circulating soluble egg antigen-antibody complex (SEAIC) in murine sera at various weeks post infection. Simultaneously, the diameter and area of liver egg granuloma were measured by using profile analytical technique. Serum SEAIC was first detected 4 weeks post infection (p.i.), reaching peak level at 6-7th week, and then gradually dropped, and maintained at moderately high level till the end of the observation (12 weeks p.i.). Schistosome eggs appeared in liver tissue at 4 weeks p.i. No egg granuloma could be found until 6 weeks p.i. The peak of the average diameter and area of liver egg granuloma was noted at 7 weeks p.i., then dropped gradually. Its dynamic changes were consistent with that of the serum SEAIC level. It is therefore suggested that the serum SEAIC level could be a reference index reflecting the extent of the pathological changes of the liver. Moreover, SEAIC might play an important role in the pathogenesis of schistosomiasis japonica.     

Prevalence of antibodies to Neospora caninum in different canid populations

A total of 1,554 dogs from 5 countries on 3 continents were tested for antibodies to Neospora caninum using an indirect fluorescent antibody test. In Australia, overall, 42/451 (9%, 95% confidence interval [CI] 6-12%) dogs were seropositive (Melbourne 11/207 [5%, 95% CI 2-9%]; Sydney 18/150 [12%, 95% CI 7-18%]; Perth 13/94 [14%, 95% CI 8-22%]). Antibodies to N. caninum were also detected in dogs in South America (Uruguay [20%, 95% CI 16-24%, n = 414]) and sub-Saharan Africa (Tanzania [22%, 95% CI 12-36%, n = 49]). In contrast, only 1 of 500 dogs tested from the Falkland Islands and none of 140 dogs from Kenya was seropositive. Of wild canids, 1/54 (2%, 95% CI 0-10%) British foxes and 15/169 (9%, 95% CI 5-14%) Australian dingoes had antibodies to N. caninum.     

Influence of bacterial overgrowth and intestinal inflammation on duration of parenteral nutrition in children with short bowel syndrome

OBJECTIVES: Massive intestinal resection results in short bowel syndrome and necessitates prolonged parenteral feeding. The purpose of this work was to assess the impact of late complications of short bowel syndrome, including intestinal bacterial overgrowth and enterocolitis, on the duration of parenteral nutrition (PN) in comparison with factors evident in the neonatal period. METHODS: Retrospective chart review. RESULTS: Of 49 children, 42 were weaned from parenteral nutrition after a treatment course of 17 +/- 14 months. In these 42, postresection small intestinal length equaled 81 +/- 65 cm; 45% had an ileocecal valve. Small intestinal length in the seven children who were PN dependent was 31 +/- 30 cm (p < 0.05); none had an ileocecal valve (p < 0.05). Bacterial overgrowth occurred in all seven PN-dependent children and in 23 of 42 children eventually weaned from PN (p < 0.05). When bacterial overgrowth was identified before weaning (n = 12), the duration pf PN was 28 +/- 17 months, but when bacterial overgrowth was first identified only after weaning (n = 11), the duration of PN was 16 +/- 13 months (p < 0.05). Small intestinal inflammation correlated with bacterial overgrowth (r = 0.69). Those children with severe enteritis identified before weaning remained on the PN regimen for 36 +/- 15 months, in comparison with 21 +/- 14 months in those with mild enteritis and 13 +/- 11 months in those without inflammation (p < 0.02). CONCLUSIONS: Although the length of small intestine remaining after resection is the best immediate predictor of final success in terminating PN in children with short bowel syndrome, PN is prolonged by bacterial overgrowth and associated enteritis in those who will ultimately be weaned.     

Prophylactic oral ganciclovir compared with deferred therapy for control of cytomegalovirus in renal transplant recipients

BACKGROUND: Treatment with prophylactic oral acyclovir, intravenous ganciclovir, or immunoglobulins to prevent cytomegalovirus (CMV) infection and disease in renal transplantation is associated with variable efficacy and significant expense. We studied control of CMV in renal transplant recipients using either prophylactic oral ganciclovir or deferred therapy with intensive monitoring with polymerase chain reaction (PCR) analysis. METHODS: Forty-two recipients were followed for 6 months after transplantation. Ganciclovir (1000 mg p.o. t.i.d.; n=19) or acyclovir (200 mg p.o. b.i.d.; n=23) was begun at transplantation and continued for 12 weeks. PCR for CMV was performed on buffy-coat specimens every week for 15 weeks and at months 5 and 6. RESULTS: No patients in the ganciclovir group, compared with 14 of 23 patients (61%) in the deferred-therapy group (P<0.0001), developed CMV disease during the first 12 weeks. In the ganciclovir group, 4 of 19 patients (21%) subsequently experienced 5 episodes, whereas 14 patients in the deferred-therapy group experienced 18 episodes (P=0.013 for subjects and P=0.026 for episodes). The time to disease was also delayed in the ganciclovir group compared with the deferred-therapy group (133+/-17 days vs. 51+/-7 days; P<0.0001). Oral ganciclovir also prevented CMV viremia during prophylaxis (2/19 patients [11%] vs. 23/23 patients [100%]). Time to CMV viremia was delayed in the ganciclovir group; however, 13/19 patients (68%) ultimately showed PCR evidence for CMV viremia (P=0.005). CONCLUSIONS: An initial 12-week course of oral ganciclovir prevents CMV disease and infection in renal transplant recipients during prophylaxis, and the benefits persist after discontinuation.     

Development of an experimental model of Microsporum canis infection in cats

An experimental infection model was developed for reliable induction of Microsporum canis skin infections in cats, using a defined number of macroconidia harvested from the fungus in culture. The strain of M. canis used produced highly fluorescent hairs under ultraviolet illumination. Kittens 8 to 9 weeks of age (n = 6) received 10(5) macroconidia applied topically to a closely-shaved area of skin. Sites were dressed with an occlusive bandage for 3 days, then grooming was restricted for an additional 4 weeks. Lesions were first observed 2 weeks after inoculation, enlarged over the following 6 to 8 weeks, then decreased in size and appeared healed at 12 to 14 weeks after inoculation. Cats often developed satellite lesions on the face, ears, or other body regions. The experimental infections strongly resembled moderately severe cases of naturally-occurring feline dermatophytosis in clinical patients. This experimental infection model will be useful for evaluation of topical and systemic treatments for feline M. canis infection.     

Pesticide residues in eggs and chicks from laying hens fed low levels of several chlorinated hydrocarbon pesticides

Eighty-four Single-Comb While Leghorn laying hens housed individually in laying cages were fed rations containing less than 0.1 p.p.m. of dieldrin, DDT, heptachlor and mirex individually or in combination for 7 days and in combination for 15 weeks. DDT residues in egg yolk reached 0.043 p.p.m. by 7 days when fed in combination with the other pesticides. None of the residues were above FDA action level at 7 days and all had declined to below trace levels by 8 weeks after termination of pesticide feeding. Residues in eggs from hens fed all four pesticides for 15 weeks increased steadily for the first few weeks and then reached a plateau or increased only slightly until pesticide feeding was terminated. By the end of the 5th week of pesticide feeding all pesticides except DDT had exceeded FDA action levels for pesticides in eggs. DDT residues reached a level of 0.139 p.p.m. by 8 weeks and did not increase thereafter. Traces of the pesticides were still present 24 weeks after termination of pesticide feeding. The pesticides tested did not affect fertility of hatchability of eggs collected during the 14th and 15th weeks of pesticide feeding. Total carcass fat of chicks hatched from these eggs had 0.024 p.p.m. dieldrin, .049 p.p.m. DDT, .001 p.p.m. heptachlor epoxide and, 0.47 mirex at 1 day of age.     

Safety and efficacy of azithromycin in the treatment of community-acquired pneumonia in children

OBJECTIVE: To compare the safety and efficacy of azithromycin with amoxicillin/clavulanate or erythromycin for the treatment of community-acquired pneumonia, including atypical pneumonia caused by Mycoplasma pneumoniae and Chlamydia pneumoniae. METHODS: Multicenter, parallel group, double blind trial in which patients 6 months to 16 years of age with community-acquired pneumonia were randomized 2:1 to receive either azithromycin for 5 days or conventional therapy for 10 days (amoxicillin/clavulanate if < or =5 years of age or erythromycin estolate if >5 years of age). Patients from 23 geographically diverse sites were evaluated for clinical outcomes and/or adverse events at Days 3 to 5, Days 15 to 19 and 4 to 6 weeks posttherapy. Microbiology (culture or polymerase chain reaction) was done at baseline and Days 15 to 19 for bacteria, Chlamydia pneumoniae and Mycoplasma pneumoniae. Serology for C. pneumoniae and M. pneumoniae was done at baseline and 4 to 6 weeks posttherapy. RESULTS: Of 456 patients enrolled during 17 consecutive months, 420 were evaluable. Clinical success at Study Days 15 to 19 was 94.6% in the azithromycin group and 96.2% in the comparative treatment group (P = 0.735) and at 4 to 6 weeks posttherapy 90.6 and 87.1%, respectively (P = 0.330). Evidence of infection was identified in 46% of 420 evaluable patients (1.9% bacteria, 29.5% M. pneumoniae and 15% C. pneumoniae). Microbiologic eradication was 81% for C. pneumoniae and 100% for M. pneumoniae in the azithromycin group vs. 100 and 57%, respectively, in the comparator group. Treatment-related adverse events occurred in 11.3% of the azithromycin group and 31% in the comparator group (P < 0.05). CONCLUSION: Azithromycin used once daily for 5 days produced a satisfactory therapeutic outcome similar to those of amoxicillin/clavulanate or erythromycin given three times a day for 10 days for treatment of community-acquired pneumonia. Azithromycin had significantly fewer side effects than comparator drugs.     

Changes in gene expression following traumatic brain injury in the rat

1. The relationship between immunoreactive inhibin and follicle-stimulating hormone (FSH) was studied in male and female chickens from hatch to sexual maturity. Plasma inhibin was estimated by a heterologous radioimmunoassay validated for use in the chicken. FSH was measured by a recently developed homologous radioimmunoassay. 2. In a cross-sectional study, blood samples and gonads were collected from chickens of both sexes at 1, 3, 5, 7, 14, 21 and 28 d after hatching and subsequently at 14-day intervals until 182 d of age. 3. In the female, plasma progesterone concentration (P4) progressively increased during sexual development. The plasma luteinising hormone (LH) concentration rose during the first week after hatching, and fluctuated thereafter, with troughs at 6 and 14 weeks and peaks at weeks 10 and 18. The plasma inhibin and FSH concentrations remained low until the start of puberty and increased simultaneously thereafter. However, from week 18 on, plasma inhibin continued to rise while plasma FSH fell. Hence, FSH and inhibin were positively correlated before puberty, but developed a negative correlation during sexual maturation. 4. In the male, plasma testosterone and LH concentrations increased 38- and 3.7-fold respectively over the period studied. Inhibin and FSH followed similar time courses and were consequently positively correlated. 5. These results suggest sex differences in the role of inhibin in regulating FSH secretion during development. The FSH-inhibin feedback loop may become operational at the onset of sexual maturity in the hens. In male chickens, the similar pattern of inhibin and FSH secretion suggests that inhibin secretion is driven by FSH.