Clinical presentations and outcomes of HIV-1 and HIV-2 among infected children in Guinea-Bissau: a nationwide study.

OBJECTIVES: Disease progression, loss to follow-up, and mortality of HIV-2 compared with HIV-1 in children is not well understood. This is the first nationwide study reporting outcomes in children with the two HIV types in Guinea-Bissau. STUDY DESIGN: Nationwide retrospective follow-up study. METHODS: This is a retrospective follow-up study among HIV-infected children <15 years at nine ART centers from 2006 to 2021. Baseline parameters and disease outcomes for children with HIV-2 and HIV-1 were compared. RESULTS: The annual number of children diagnosed with HIV peaked in 2017. HIV-2 (n = 64) and HIV-1 (n = 1945) infected children were different concerning baseline median age (6.5 vs 3.1 years, P < 0.01), but had similar levels of severe immunodeficiency (P = 0.58) and severe anemia (P = 0.26). Within the first year of follow-up, 36.3% were lost, 5.9% died, 2.7% had transferred clinic, and 55.2% remained for follow-up. Mortality (HR = 1.05 95% CI: 0.53-2.08 for HIV-2) and attrition (HR = 0.86 95% CI: 0.62-1.19 for HIV-2) rates were similar for HIV types. CONCLUSIONS: The decline in children diagnosed per year since 2017 is possibly due to lower HIV prevalence, lack of HIV tests, and the SARS-CoV-2 epidemic. Children with HIV-2 were twice as old as HIV-1 infected when diagnosed, which suggests a slower disease progression. However, once they develop immunosuppression mortality is similar.

Fever increases heart rate and respiratory rate; a prospective observational study of acutely admitted medical patients.

BACKGROUND: The relationship between increase in body temperature, heart rate, and respiratory rate has only been studied in young, healthy subjects. AIM: To show the changes in heart and respiratory rate associated with fever in acutely admitted medical patients. DESIGN: A prospective observational cohort study. METHODS: Vital parameters from 4,493 patients were retrospectively extracted. Linear and multiple variable regression analysis was used to calculate the change in heart and temperature rate for every degree rise in temperature (i.e. ΔHR/°C and ΔRR/°C) in the entire study group and in those with low (<36.1°C), normal (36.1-38°C) and high (>38°C) body temperatures. RESULTS: The ΔHR/°C and ΔRR/°C was 7.2±0.4 beats per minute (bpm) and 1.4 ±0.1 (1.2 to 1.62) breaths per minute (bpm). Adjusting for age, oxygen saturation and mean blood pressure, the results were 6.4±0.4 (5.7 to 7.1) bpm and 1.2±0.1 (1.0 to 1.4) bpm. In low, normal and high body temperature the ΔHR/°C were 2.7±1.9, 6.9±1.9 and 7.4±0.9 bpm, respectively; for ΔRR/°C the values were -0.5±0.5, 1.5±0.5 and 2.3±0.3 bpm, respectively. CONCLUSIONS: We only found a modest association between fever and changes in heart rate and respiratory rate.

Synthesis and characterization of O-acylated-ω-hydroxy fatty acids as skin-protecting barrier lipids.

A series of O-acylated-ω-hydroxy fatty acids (Acyl acids) of up to 34 carbons were synthesized and characterized through DSC, FTIR and Langmuir isotherm measurements to identify potential replacements to petrolatum, a highly used occlusive technology that if unrefined, it can potentially be classified as carcinogenic. Fourier transform infrared spectroscopy studies demonstrated that long acyl acids engender orthorhombic packing; packing behavior that is predominant in the lipid matrix of healthy stratum corneum, the outmost layer of the skin. In addition, Differential Scanning Calorimetry (DSC) and Langmuir isotherm studies suggested that the length of the hydrocarbon chain and the position of the ester bond influence the molecular organization of the acyl acids. For instance, 16-(tetradecanoyloxy)hexadecanoic acid (30 carbons) displayed a higher melting point (mp=68°C) than 10-(stearoyloxy)decanoic acid (28 carbons; mp=63°C) and 10-(tetradecanoyloxy)decanoic acid (24 carbons; mp=55°C) according to DSC. Moreover, Langmuir isotherm studies showed that mixtures of acyl acid with distearoylphosphatidylcholine improved packing behavior. Finally, Water Vapor Transmission Rate (WVTR) measurements showed that the compounds in fact decrease WVTR compared to untreated control (P<0.001) which demonstrates the potential of these ingredients as occlusive technologies to combat skin barrier diseases.

Hypoglycaemia in adults with insulin-treated diabetes in the UK: self-reported frequency and effects.

AIM: Few real-life studies of non-severe (self-treated) hypoglycaemic events are available. This survey quantified the self-reported frequency of non-severe hypoglycaemia and its effects in adults with insulin-treated diabetes in the UK. METHODS: Adults aged > 15 years with Type 1 diabetes or insulin-treated Type 2 diabetes completed ≤ 4 weekly questionnaires (7-day recall). Respondents with Type 2 diabetes were grouped by insulin regimen: basal-only, basal-bolus and 'other'. RESULTS: Overall, 1038 respondents (466 with Type 1 diabetes, 572 with Type 2 diabetes) completed 3528 questionnaires. Mean numbers of non-severe events per week were 2.4 (Type 1 diabetes; median = 2) and 0.8 (Type 2 diabetes; median = 0); 23% and 26% of non-severe events occurred at night, respectively. Fatigue and reduced alertness were the commonest issues following events (78% and 51% of respondents, respectively). The effects of nocturnal events persisted longer than those of daytime events: Type 1 diabetes = 10.6 vs. 4.9 h (P = 0.0002); Type 2 diabetes = 15.3 vs. 5.1 h (P < 0.0001). In the week following an event, respondents' blood glucose measurements increased by 4.3 (Type 1 diabetes; 12% increment) and 4.2 (Type 2 diabetes; 21% increment) tests/week. In employed respondents, 20% of events caused work-time loss, more so following nocturnal (vs. daytime) hypoglycaemia: Type 1 diabetes = 2.7 vs. 1.1 h (P = 0.0184); Type 2 diabetes = 2.5 vs. 1.6 h (P = 0.1340). Most respondents rarely/never informed healthcare professionals about events (Type 1 diabetes = 82%, Type 2 diabetes = 69%). CONCLUSIONS: Non-severe hypoglycaemia is common in adults with insulin-treated diabetes in the UK, with consequent health-related/economic effects. Communication about non-severe hypoglycaemia is limited and the burden of hypoglycaemia may be underestimated.

Aging impairs the recovery in mechanical muscle function following 4 days of disuse.

As aged individuals are frequently exposed to short-term disuse caused by disease or musculoskeletal injury, it is important to understand how short-term disuse and subsequent retraining affect lower limb mechanical muscle function. The purpose of the present study was, therefore, to investigate the effect of 4 days of lower limb disuse followed by 7 days of active recovery on mechanical muscle function of the knee extensors in young (24.3±0.9 years, n=11) and old (67.2±1.0 years, n=11) recreationally active healthy males. Slow and moderate dynamic muscle strength were assessed using isokinetic dynamometry (60 and 180° s(-1), respectively) along with isometric muscle strength and rapid muscle force capacity examined as contractile rate of force development (RFD), Impulse, and relative RFD (rRFD) during the initial phase of contraction (100 ms time interval relative to onset of contraction). Prior to disuse, marked age-related differences (p<0.05) were observed in isometric and dynamic muscle strength (~35%) as well as in RFD and Impulse (~39%). Following disuse, young and old individuals experienced comparable decrements (p<0.05) in isometric strength (~9%), slow dynamic strength (~13%), and RFD and Impulse (~19%), whereas old individuals only experienced decrements (p<0.05) in moderate dynamic strength (12%) and rRFD (~17%). Following recovery, all measures of mechanical muscle function were restored in young individuals compared to pre-disuse values, while isometric, slow and moderate dynamic muscle strength remained suppressed (p<0.05) in old individuals (~8%) along with a tendency to suppressed RFD100 (p=0.068). In conclusion, 4 days of lower limb disuse led to marked decrements in knee extensor mechanical muscle function in both young and old individuals, yet with greater decrements observed in moderate dynamic strength and rapid muscle force capacity in old individuals. While 7 days of recovery - including free ambulation, one test session and a single session of strength training - was sufficient to restore mechanical muscle function in young individuals, old individuals appeared to have an impaired ability to fully recover as evidenced by suppressed values of isometric and dynamic muscle strength and rapid muscle force capacity.

Bacillus subtilis (DSM17299) significantly reduces Salmonella in broilers.

Salmonella continues to be a major public health burden worldwide. Poultry are known to be one of the main reservoirs for this zoonotic pathogen. It has previously been shown that a single dose of Bacillus subtilis reduces fecal shedding of Salmonella enterica serovar Enteritidis, whereas no effect on long-term colonization of the cecum has been observed. Here we report experiments that were undertaken to test the efficacy of a conventional diet supplemented with a probiotic (B. subtilis DSM17299) on 1) Salmonella colonization in the intestinal tract of broiler chickens, and 2) fecal shedding of Salmonella under production-like conditions. The trial birds fed the B. subtilis diet showed a significant 58% reduction in Salmonella-positive drag swabs compared with control birds, which had 100% presence of Salmonella. Feeding B. subtilis significantly reduced the average Salmonella load of cecum samples of the chickens, by 3 log units. This reduction in Salmonella colonization might not only positively affect broilers on the live production side by reducing the risk of infection between birds, but could also aid on the processing side by decreasing the amount of Salmonella entering the facility and improving food safety. Furthermore, numerical, but not statistically significant, improvements in feed conversion rate and BW gain at d 42 were observed in the B. subtilis-treated group compared with control birds.

Purification, characterization, and crystallization of the components of the nitrobenzene and 2-nitrotoluene dioxygenase enzyme systems.

The protein components of the 2-nitrotoluene (2NT) and nitrobenzene dioxygenase enzyme systems from Acidovorax sp. strain JS42 and Comamonas sp. strain JS765, respectively, were purified and characterized. These enzymes catalyze the initial step in the degradation of 2-nitrotoluene and nitrobenzene. The identical shared reductase and ferredoxin components were monomers of 35 and 11.5 kDa, respectively. The reductase component contained 1.86 g-atoms iron, 2.01 g-atoms sulfur, and one molecule of flavin adenine dinucleotide per monomer. Spectral properties of the reductase indicated the presence of a plant-type [2Fe-2S] center and a flavin. The reductase catalyzed the reduction of cytochrome c, ferricyanide, and 2,6-dichlorophenol indophenol. The ferredoxin contained 2.20 g-atoms iron and 1.99 g-atoms sulfur per monomer and had spectral properties indicative of a Rieske [2Fe-2S] center. The ferredoxin component could be effectively replaced by the ferredoxin from the Pseudomonas sp. strain NCIB 9816-4 naphthalene dioxygenase system but not by that from the Burkholderia sp. strain LB400 biphenyl or Pseudomonas putida F1 toluene dioxygenase system. The oxygenases from the 2-nitrotoluene and nitrobenzene dioxygenase systems each had spectral properties indicating the presence of a Rieske [2Fe-2S] center, and the subunit composition of each oxygenase was an alpha(3)beta(3) hexamer. The apparent K(m) of 2-nitrotoluene dioxygenase for 2NT was 20 muM, and that for naphthalene was 121 muM. The specificity constants were 7.0 muM(-1) min(-1) for 2NT and 1.2 muM(-1) min(-1) for naphthalene, indicating that the enzyme is more efficient with 2NT as a substrate. Diffraction-quality crystals of the two oxygenases were obtained.

The Outpatient Developmental Services Project: integration of pediatric psychology with primary medical care for children infected with HIV.

OBJECTIVE: To present a model in which pediatric psychology services are programmatically integrated into the primary care of children seen in a special immunology program. The program centers around serial neurodevelopmental/neuropsychological evaluation of children infected with HIV. METHOD: We describe the population served and the particular services provided, with specific focus on how the program was developed. We include a discussion of the barriers to service provision that have been encountered and the strategies employed to overcome these challenges. CONCLUSIONS: This approach, while not ideal, serves as a good example of how pediatric psychology can merge with primary medical care to maximize the benefits of both specialties for a patient population that is underserved in many respects.

Single-dose spinal anaesthesia versus incremental dosing for lower limb vascular surgery.

BACKGROUND: In patients scheduled for vascular surgery, atherosclerotic disease is highly prevalent. Haemodynamic reactions are often aggravated when spinal analgesia is used in this population. No randomized studies have been conducted comparing single shot (SS) with continuous spinal analgesia (CSA) for vascular patients. We did a prospective randomized study comparing haemodynamics when SS versus CSA was performed. METHODS: Sixty patients were randomized to have SS or CSA. The power of the study was 0.90. Patients in the SS group received 17.5 mg bupivacaine and in the CSA group 5 mg was given initially and incremental doses of 2.5 mg were given until an analgesic level of T-11 was reached. Mean arterial pressures (MAP) were measured invasively. ST-analysis was done continuously. Postoperatively, the patients were interviewed using a standardized questionnaire. Back pain, neurologic sequelae and post-dural puncture headache (PDPH) were investigated. RESULTS: There was no significant difference between the analgesic levels (T-7/T-8), the decrease in MAP, the number of patients needing ephedrine and the total amount of ephedrine given in the two groups. The motor blockade was more pronounced in the SS group (P < 0.001) and the total amount of bupivacaine used was 17.5 mg compared to 7.5 mg (5-17.5) in the CSA group (P < 0.001). One patient suffered PDPH which was slight and responded to a nonsteroidal anti-inflammatory drug. Two patients in each group had transient paraesthesias in the legs. There were technical problems with the spinal catheter in 4 patients, and these were excluded from the study. CONCLUSION: In this study we found no difference in the haemodynamic response to SS or CSA in patients scheduled for vascular surgery of the legs. SS is easier to apply and is recommended when the duration of surgery allows for it.

Comparing the rates and the activation parameters for the forward reaction between the triplet state of zinc cytochrome c and cupriplastocyanin and the back reaction between the zinc cytochrome c cation radical and cuproplastocyanin.

This is a comparative study of the photoinduced (so-called forward) electron-transfer reaction 3Zncyt/pc(II) --> Zncyt+/pc(I), between the triplet state of zinc cytochrome c (3Zncyt) and cupriplastocyanin [pc(II)], and the thermal (so-called back) electron-transfer reaction Zncyt+/pc(I) --> Zncyt/pc(II), between the cation (radical) of zinc cytochrome c (Zncyt+) and cuproplastocyanin [pc(I)], which follows it. Both reactions occur between associated (docked) reactants, and the respective unimolecular rate constants are kF and kB. Our previous studies showed that the forward reaction is gated by a rearrangement of the diprotein complex. Now we examine the back reaction and complare the two. We study the effects of temperature (in the range 273.3-302.9 K) and viscosity (in the range 1.00-17.4 cP) on the rate constants and determine enthalpies (DeltaH), entropies (DeltaS), and free energies (DeltaG) of activation. We compare wild-type spinach plastocyanin, the single mutants Tyr83Leu and Glu59Lys, and the double mutant Glu59Lys/Glu60Gln. The rate constant kB for wild-type spinach plastocyanin and its mutants markedly depends on viscosity, an indication that the back reaction is also gated. The activation parameters DeltaH and DeltaS show that the forward and back reactions have similar mechanisms, involving a rearrangement of the diprotein complex from the initial binding configuration to the reactive configuration. The rearrangements of the complexes 3Zncyt/pc(II) and Zncyt+/pc(I) that gate their respective reactions are similar but not identical. Since the back reaction of all plastocyanin variants is faster than the forward reaction, the difference in free energy between the docking and the reactive configuration is smaller for the back reaction than for the forward reaction. This difference is explained by the change in the electrostatic potential on the plastocyanin surface as Cu(II) is reduced to Cu(I). It is the smaller DeltaH that makes DeltaG smaller for the back reaction than for the forward reaction.

Effects of single and double mutations in plastocyanin on the rate constant and activation parameters for the rearrangement gating the electron-transfer reaction between the triplet state of zinc cytochrome c and cupriplastocyanin.

The unimolecular rate constant for the photoinduced electron-transfer reaction 3Zncyt/pc(II) --> Zncyt+/pc(I) within the electrostatic complex of zinc cytochrome c and spinach cupriplastocyanin is kF. We report the effects on kF of the following factors, all at pH 7.0: 12 single mutations on the plastocyanin surface (Leu12Asn, Leu12Glu, Leu12Lys, Asp42Asn, Asp42Lys, Glu43Asn, Glu59Gln, Glu59Lys, Glu60Gln, Glu60Lys, Gln88Glu, and Gln88Lys), the double mutation Glu59Lys/Glu60Gln, temperature (in the range 273.3-302.9 K), and solution viscosity (in the range 1. 00-116.0 cP) at 283.2 and 293.2 K. We also report the effects of the plastocyanin mutations on the association constant (Ka) and the corresponding free energy of association (DeltaGa) with zinc cytochrome c at 298.2 K. Dependence of kF on temperature yielded the activation parameters DeltaH, DeltaS, and DeltaG. Dependence of kF on solution viscosity yielded the protein friction and confirmed the DeltaG values determined from the temperature dependence. The aforementioned intracomplex reaction is not a simple electron-transfer reaction because donor-acceptor electronic coupling (HAB) and reorganizational energy (lambda), obtained by fitting of the temperature dependence of kF to the Marcus equation, deviate from the expectations based on precedents and because kF greatly depends on viscosity. This last dependence and the fact that certain mutations affect Ka but not kF are two lines of evidence against the mechanism in which the electron-transfer step is coupled with the faster, but thermodynamically unfavorable, rearrangement step. The electron-transfer reaction is gated by the slower, and thus rate determining, structural rearrangement of the diprotein complex; the rate constant kF corresponds to this rearrangement. Isokinetic correlation of DeltaH and DeltaS parameters and Coulombic energies of the various configurations of the Zncyt/pc(II) complex consistently show that the rearrangement is a facile configurational fluctuation of the associated proteins, qualitatively the same process regardless of the mutations in plastocyanin. Correlation of kF with the orientation of the cupriplastocyanin dipole moment indicates that the reactive configuration of the diprotein complex involves the area near the residue 59, between the upper acidic cluster and the hydrophobic patch. Kinetic effects and noneffects of plastocyanin mutations show that the rearrangement from the initial (docking) configuration, which involves both acidic clusters, to the reactive configuration does not involve the lower acidic cluster and the hydrophobic patch but involves the upper acidic cluster and the area near the residue 88.

Colicin V38 and microcin C38 produced by Escherichia coli strain 38.

Escherichia coli strain 38, an isolate from turkeys, has been previously shown to produce one or more broad-spectrum bacteriocins against other related enteric bacteria. Using a collection of E. coli strains that synthesized well-characterized colicins or microcins, along with a set of colicin/microcin-insensitive mutants, we were able to classify the bacteriocins produced by strain 38. We determined that strain 38 produced a microcin (microcin C38) and a colicin (colicin V38) and that the amount of microcin C38 depended on the type of media on which it was grown. Escherichia coli strain 38 was found to have cross-immunity with the microcin C7-producing strain MC4100 and with the colicin V-producing strain 4674. OmpF mutant cells were found to be insensitive to microcin C38, whereas colicin V38 was not active on cells that had a cir mutation. Both microcin C38 and colicin V38 were inactivated by proteases. Microcin C38 was stable at extremes of pH (pH 1.5 and pH 13) and heat (10 min at 98 C) conditions, whereas colicin V38 was not. In addition, microcin C38 was found to be active against a broader spectrum of gram-negative bacteria than was colicin V38.

Effects of viscosity and temperature on the kinetics of the electron-transfer reaction between the triplet state of zinc cytochrome c and cupriplastocyanin.

This is a study of the effects of viscosity (in the range of 0.8-790 cP), of temperature (in the range of 260.7-307.7 K), and of ionic strength (in the range of 2.5-20.0 mM) on the kinetics of photoinduced electron-transfer reaction 3Zncyt/pc(II) --> Zncyt+/pc(I) within the electrostatic complex of zinc cytochrome c and cupriplastocyanin at pH 7.0. The unimolecular rate constant is kF. The apparent activation parameters DeltaH*, DeltaS*, and DeltaG* for this reaction were obtained in experiments with aqueous glycerol solutions having a constant composition. The interpolation of kF values obtained at the constant composition into the dependence of kF on temperature at constant viscosity gave the proper activation parameters, which agree with those obtained in experiments with solutions having a constant viscosity. This agreement validates the latter method, which is more efficient than the former, for determining activation parameters of processes that are modulated by viscosity. The smooth change in kF is governed by the change in viscosity, not in other properties of the solvent, and it does not depend on the choice of the viscosigen. Donor/acceptor electronic coupling (HAB) and reorganizational energy (lambda), obtained by fitting of the temperature dependence of kF to the Marcus equation, are consistent with true electron transfer and with electron transfer that is coupled to, or gated by, a preceding structural rearrangement of the diprotein complex 3Zncyt/pc(II). The fact that at very high viscosity kF approaches zero shows that the reaction is probably gated throughout the investigated range of viscosity. Kinetic effects and noneffects of ionic strength, viscosity, and thermodynamic driving force indicate, but do not prove, that the reaction under consideration is gated. The kinetic effect of viscosity is analyzed in terms of two models. Because ln kF is a nonlinear function of ln eta, protein friction has to be considered in the analysis of viscosity effects on kinetics.

Effects of temperature on the kinetics of the gated electron-transfer reaction between zinc cytochrome c and plastocyanin. Analysis of configurational fluctuation of the diprotein complex.

This is a study of the effects of temperature (in the range 273.3-307.7 K) and of ionic strength (in the range 2.5-100 mM) on the kinetics of photoinduced electron-transfer reaction 3Zncyt/pc(II)--> Zncyt+/pc(I) within the electrostatic complex of zinc cytochrome c and cupriplastocyanin at pH 7.0. In order to separate direct and indirect effects of temperature on the rate constants, viscosity of the solutions was fixed, at different values, by additions of sucrose. The activation parameters for the reaction within the preformed complex, at the low ionic strength, are delta H++ = 13 +/- 2 kJ/mol and delta S++ = -97 +/- 4 J/K mol. The activation parameters for the reaction within the encounter complex, at the higher ionic strength, are delta H++ = 13 +/- 1 kJ/mol and delta S++ = -96 +/- 3 J/K mol. Evidently, the two complexes are the same. The proteins associate similarly in the persistent and the transient complex, i.e., at different ionic strengths. In both complexes, however, electron transfer is gated by a rearrangement, as previous studies from this laboratory showed. Changes in the solution viscosity modulate this rearrangement by affecting delta H++, not delta S++. The activation parameters are analyzed by empirical methods. The thermodynamic parameters delta H and delta S for the formation of the complex Zncyt/pc(II) are determined and related to changes in hydrophilic and hydrophobic surfaces upon protein association in three configurations. A difference between the values of delta H for the configuration providing optimal electronic coupling between the redox sites and the configuration providing optimal docking equals the experimental value delta H++ = 13 kJ/mol for the rearrangement of the latter configuration into the former. Enthalpy of activation may reflect a change in the character of the exposed surface as the diprotein complex rearranges. Entropy of activation may reflect tightening of the contact between the associated proteins.

Correlation between level of (n - 3) polyunsaturated fatty acids in brain phospholipids and learning ability in rats. A multiple generation study.

The effects of dietary n - 3 polyunsaturated fatty acids (PUFAs) on major brain phospholipids were examined in the rat throughout four generations. Dietary fats were: a seal oil (22:6(n - 3) located mainly in the sn-1/3-position of the TG); a fish oil (22:6(n - 3) located mainly in the sn-2 position of the TG); or a vegetable oil containing 18:3(n - 3). The effect of the TG structure of the dietary fat and chain length of n - 3 PUFA on assimilation in the brain was compared with chow fed rats. The rats fed marine fats had significantly higher levels of long-chain n - 3 PUFAs in brain PE and PS, compared to the vegetable oil and chow fed rats, but no effects of TG structure of dietary fat were observed. Dietary 18:3(n - 3) raised the amount of 22:6(n - 3) compared to the control group, but not to the levels of the marine groups that received preformed 22:6(n - 3). Fish oil fed rats had higher levels of 20:5(n - 3) and 22:5(n - 3) compared with the seal oil fed rats, whereas 22:6(n - 3) were similar. Only minor changes in PI, PIP, and PIP2 were found. The fourth generation was tested for spatial learning ability in a Morris water maze. The experimental groups had similar learning abilities, which were increased compared to the control group.

Influence of triacylglycerol structure and fatty acid profile of dietary fats on milk triacylglycerols in the rat. A two-generation study.

We investigated the influence of dietary fatty acid profile and triacylglycerol structure on the fatty acid profile and triacylglycerol structure of milk lipids in two generations of rats. Three groups of rats received diets containing 20% fat of which approximately 20% was n-3 fatty acids located in different positions of the triacylglycerol: a fish oil-based diet [docosahexaenoic acid (22:6n-3) predominantly in the sn-2 position], a seal oil-based diet (22:6n-3) predominantly in the sn-1/sn-3 position, or a plant oil-based diet [alpha-linolenic acid (18:3n-3) distributed evenly between the three positions]. This design allowed us to investigate (i) the effect of the triacylglycerol structure of the dietary fat; (ii) the effect of receiving the n-3 fatty acids as long-chain derivatives or as the precursor, 18:3n-3; and (ii) the long-term effects over two generations. The fatty acid profiles of the milk lipids largely reflected the diets, but in the second generation, the level of medium-chain fatty acids was higher (P < 0.05) in the milk from rats fed the fish oil diet (24%) compared with the other dietary groups (15 and 18%). This suggests an increased endogenous synthesis of fatty acids in the mammary glands of the fish oil-fed rats. The levels of long-chain n-3 fatty acids in milk were higher (P < 0.05) in rats fed marine oils (8-12%) compared with rats fed vegetable oil (1%) in both generations. The level of long-chain n-3 fatty acids was significantly higher in the milk from the fish oil-fed rats (12.3%) compared to the seal- oil fed rats (8.0%) in the first generation, but not in the second generation (8.9 vs. 9.1%). The general structure of milk triacylglycerols was maintained in the three experimental groups with 16:0 acylated in the sn-2 position and 18:1 in the sn-1/sn-3 positions. The triacylglycerol structure of mammalian milk appears to be conserved even during extreme dietary manipulation over two generations and an extensive enrichment with long-chain n-3 polyunsaturated fatty acids requires their presence in the diet.

Intestinal absorption of octanoic, decanoic, and linoleic acids: effect of triglyceride structure.

The influence of triglyceride structure on the intestinal absorption of specific triglycerides was investigated. A bolus of either a structured or a randomized oil was given to lymph-cannulated rats. The structured oil contained medium-chain fatty acids (MCFA) in the sn-1 and sn-3 position of the triglyceride, and linoleic acid (C18:2 n-6) in the sn-2 position, whereas in the randomized oil the same fatty acids were distributed randomly between the three positions. The absorption of MCFA was highest from the randomized oil, where approximately 33% of the MCFA were located in the sn-2 position. The absorption of C18:2 n-6 was highest from the structured oil, where C18:2 n-6 is located in the sn-2 position, indicating that the intestinal absorption is influenced by triglyceride structure, and that the absorption is enhanced for fatty acids located in the sn-2 position. Prior to lymph collection, the rats were fed either a fish oil or a vegetable oil diet. The absorption of C18:2 n-6 was highest in the rats previously fed the fish oil diet. The incorporation of the highly unsaturated fatty acids from the fish oil into the membrane phospholipids may thus influence the absorption of fat.

Staphylococcosis of turkeys. 6. Development of penicillin resistance in an interfering strain of Staphylococcus epidermidis.

Staphylococcus epidermidis strain 115, used as an interfering agent to help reduce the incidence of staphylococcosis in turkeys, was converted into a penicillin- and chloramphenicol-resistant strain designated 115R. This was accomplished by introducing a plasmid carrying the beta-lactamase (penicillinase) and chloramphenicol-resistance genes into S. epidermidis 115 by electroporation. The resultant strain, 115R, was an efficient producer of beta-lactamase and had marked increased resistance to penicillin and chloramphenicol. A beta-lactamase DNA probe was used to confirm the presence of the beta-lactamase gene in strain 115R. S. epidermidis strain 115R retained the characteristics of tissue adherence, bacteriocin production, and non-virulence that were present in the original non-transformed strain 115, and in addition should theoretically remain colonized in poults following treatment with penicillin.

Occlusive laryngotracheitis in turkeys following drinking water administration of gentian violet.

Acute respiratory signs and increased mortality due to suffocation occurred in a flock of 5-week-old male turkey poults following water administration of gentian violet. Gross lesions of laryngeal edema and occlusion of the tracheal opening with caseous plugs were present. Microscopic lesions in the tracheas consisted of vascular congestion, mucosal degeneration, and necrosis. The condition was reproduced experimentally in turkey poults by giving drinking water containing gentian violet.