Effect of MK-801 on seizures induced by exposure to hyperbaric oxygen: comparison with AP-7.

The effect of the noncompetitive N-methyl-d-aspartate (NMDA)-receptor antagonist MK-801 on seizures induced by hyperbaric oxygen in relation to changes in cerebral blood flow (CBF) was investigated. Rats were injected with MK-801 (0.005-8 mg/kg) 30 min before exposure to 100% O2 at 5 atm (gauge pressure).

Notes on the phlebotomine sand flies from the Peruvian southeast--I. Description of Lutzomyia (Helcocyrtomyia) adamsi n. sp. (Diptera: Psychodidae).

A new species of phlebotomine sand fly, Lutzomyia adamsi n. sp., is described and illustrated from specimens collected during August 1994, in Sandia, Department of Puno-Peru.

Age-dependent susceptibility to severe disease with primary exposure to Plasmodium falciparum.

This study investigated the incidence of severe disease following primary exposure to Plasmodium falciparum by nonimmune children and adults in Irian Jaya, Indonesia. Four months after arrival, the cross-sectional prevalence of P. falciparum was 72%, and the monthly cumulative incidence of clinical diagnoses of malaria was 81%.

Age-dependent characteristics of protection v. susceptibility to Plasmodium falciparum.

Naturally acquired immunity to Plasmodium falciparum may be linked to key features of the immune system that change during normal development and ageing. Evidence of this was seen in non-immune Javanese transmigrants taking up residence in hyperendemic Irian Jaya, Indonesia. After 1-2 years of residence, the adult migrants had less frequent and less intense parasitaemias than their children.

Decompression sickness presenting as forearm swelling and peripheral neuropathy: a case report.

Neurological symptoms after decompression from a dive are usually thought to be manifestations of central nervous system (CNS) decompression sickness (DCS). We present a case of DCS in which neurological symptoms are present but which the clinical findings, magnetic resonance imaging and electroneuromyographic studies suggest were caused by muscle injury and exacerbation of an existing peripheral neuropathy. This finding supports the alternative hypothesis that some neurological symptoms and signs in DCS are due to effects on peripheral nerves rather than the CNS.

Cutaneous lesions in swine after decompression: histopathology and ultrastructure.

A detailed histopathologic description of skin lesions from a porcine model of decompression sickness (DCS) is presented. Pigs were dived in a dry chamber on a variety of profiles over an 11-mo period, with a 0.1-0.

Changes in human brainstem auditory evoked potentials during a 1,100 kPa He-O2 simulated saturation dive.

Four divers were chosen as subjects to conduct the 1,100 kPa He-O2 simulated saturation dive. Brainstem auditory evoked potentials of the divers were monitored during different stages of the exposure. At 1,100 kPa, with both 10 and 50 Hz clicks, interpeak latencies I-V were prolonged by 0.

Genetic analysis of isolates of the spotted fever group of rickettsiae belonging to the R. conorii complex.

The cytoplasmic 120 kDa antigen genes of 9 isolates of Rickettsia conorii (RC), 12 isolates of R. africae (RA), and 3 isolates of Israeli tick typhus rickettsiae (ISTT) were compared for restriction fragment length polymorphisms (RFLP) present in portions of the open reading frame amplified by polymerase chain reaction (PCR). Initially, DNAs from 13 species or serotypes of spotted fever group rickettsiae were used to select restriction enzymes (RE) that detected RFLP in gene fragments amplified with primer pairs 483WF/1514R and 764F/3409R.

Expression and refolding of truncated recombinant major outer membrane protein antigen (r56) of Orientia tsutsugamushi and its use in enzyme-linked immunosorbent assays.

The variable 56-kDa major outer membrane protein of Orientia tsutsugamushi is the immunodominant antigen in human scrub typhus infections. The gene encoding this protein from Karp strain was cloned into the expression vector pET11a. The recombinant protein (r56) was expressed as a truncated nonfusion protein (amino acids 80 to 456 of the open reading frame) which formed an inclusion body when expressed in Escherichia coli BL21.

Fever in the returned traveler.

The most important cause of fever in the returned traveler is malaria. All febrile patients in which malaria is epidemiologically possible require urgent evaluation for P. falciparum malaria, which can be rapidly fatal in the nonimmune patient.

Neuropeptide Y and Y1-receptor agonists increase blood flow through arteriovenous anastomoses in rat tail.

The purpose of this study was to characterize neuropeptide Y (NPY)-induced vasodilation in the rat tail. Sterile surgical technique was used (with pentobarbital sodium anesthesia) to equip rats with a jugular catheter and a blind-ended thermocouple reentrant tube next to the carotid artery. Tail skin and core temperature were measured with thermocouples during experiments.

Acute effects of a bicyclophosphate neuroconvulsant on monoamine neurotransmitter and metabolite levels in the rat brain.

Naive male Sprague-Dawley rats were injected intraperitoneally (i.p.) with the bicyclophosphate convulsant trimethylolpropane phosphate (TMPP) at dose levels from 0.

Overexpression of protein kinase C alpha enhances lipopolysaccharide-induced nitric oxide formation in vascular smooth muscle cells.

Our previous studies showed that lipopolysaccharide (LPS)-induced nitric oxide (NO) synthesis in cardiovascular tissues is attenuated by protein kinase C (PKC) inhibitors. In the current study, we identify a specific PKC isotype involved in the LPS signal transduction pathway that leads to NO formation in rat vascular smooth muscle cells (VSMC). VSMC were transfected with a mammalian expression vector containing a full length PKCalpha cDNA insert, and a stable transfectant overexpressing PKCalpha was obtained as evidenced by increased expression of PKCalpha mRNA and protein.

Protective efficacy of a dengue 2 DNA vaccine in mice and the effect of CpG immuno-stimulatory motifs on antibody responses.

A recently described DNA vaccine for dengue (DEN) type 2 was shown to elicit high levels of neutralizing antibodies in mice. The vaccine candidate consists of the PreM and 92% of the envelope genes of DEN 2 New Guinea C strain. We further evaluated this DNA vaccine candidate by examining the effect of immuno-stimulatory CpG DNA motifs on antibody response and by studying the protective efficacy of the vaccine.

Protection of mice against Plasmodium yoelii sporozoite challenge with P. yoelii merozoite surface protein 1 DNA vaccines.

Immunization of mice with DNA vaccines encoding the full-length form and C and N termini of Plasmodium yoelii merozoite surface protein 1 provided partial protection against sporozoite challenge and resulted in boosting of antibody titers after challenge. In C57BL/6 mice, two DNA vaccines provided protection comparable to that of recombinant protein consisting of the C terminus in Freund's adjuvant.

Boosting with recombinant vaccinia increases immunogenicity and protective efficacy of malaria DNA vaccine.

To enhance the efficacy of DNA malaria vaccines, we evaluated the effect on protection of immunizing with various combinations of DNA, recombinant vaccinia virus, and a synthetic peptide. Immunization of BALB/c mice with a plasmid expressing Plasmodium yoelii (Py) circumsporozoite protein (CSP) induces H-2Kd-restricted CD8+ cytotoxic T lymphocyte (CTL) responses and CD8+ T cell- and interferon (IFN)-gamma-dependent protection of mice against challenge with Py sporozoites. Immunization with a multiple antigenic peptide, including the only reported H-2Kd-restricted CD8+ T cell epitope on the PyCSP (PyCSP CTL multiple antigenic peptide) and immunization with recombinant vaccinia expressing the PyCSP induced CTL but only modest to minimal protection.

Role of cerebral blood flow in seizures from hyperbaric oxygen exposure.

Hyperbaric O2 exposure causes seizures by an unknown mechanism. Cerebral blood flow (CBF) may affect seizure latency, although no studies have demonstrated a direct relationship. Awake rats (male, Sprague-Dawley, 350-450 g), instrumented for measuring electroencephalographic activity (EEG) and CBF (laser-Doppler flowmetry), were exposed to 100% O2 at 4 or 5 atm (gauge pressure) until EEG seizures.

Metabolic and endocrine responses to cold air in women differing in aerobic capacity.

Purpose: The purpose of this study was to measure resting metabolic rate, plasma norepinephrine, and plasma immunoreactive beta endorphin during exposures to cold air during two consecutive 5-d periods, separated by 2 weekend days, in two groups of women differing in aerobic fitness.

Methods: Plasma norepinephrine (NE), plasma immunoreactive beta-endorphin (IBE), and resting metabolic response (RMR) were measured during repeated exposures to 3.5 degrees C air in two groups of women differing in aerobic fitness.

Human immunodeficiency virus proviral DNA from peripheral blood and lymph nodes demonstrates concordant resistance mutations to zidovudine (codon 215) and didanosine (codon 74). Division of AIDS Treatment Research Initiative 003 Study Group.

Genotypes that confer drug resistance were evaluated in human immunodeficiency virus (HIV) proviral DNA obtained from peripheral blood mononuclear cells (PBMC) and lymphoid tissue at baseline and after 8 weeks of therapy with zidovudine alone or in combination with didanosine from 22 patients (8 zidovudine-naive and 14 zidovudine-experienced). There was evidence of zidovudine resistance at codon 215 in 27.3% (6/22) of patients.

Immunogenicity of Plasmodium falciparum circumsporozoite protein multiple antigen peptide vaccine formulated with different adjuvants.

Only low antibody levels were obtained from vaccinating human volunteers with single-chain peptide from the Plasmodium falciparum circumsporozoite protein (PfCSP). This resulted in modest protection against sporozoite challenge. In addition, HLA restriction limits the probability of synthesis of a vaccine effective for a diverse population.

Evaluation of the protective efficacy of a recombinant dengue envelope B domain fusion protein against dengue 2 virus infection in mice.

A recombinant protein containing part of the dengue (DEN) 2 envelope protein was evaluated as a subunit immunogen for vaccination against DEN virus infection. A gene fragment encoding amino acids 298-400 (B domain) of the DEN-2 virus envelope was expressed as a fusion protein with the maltose binding protein (MBP) of Escherichia coli. This recombinant, DEN-2(B)/MBP, was purified and analyzed for its antigenicity, immunogenicity, and ability to protect mice against lethal challenge.

Electric cautery lowers the contamination threshold for infection of laparotomies.

Background: Interplay between wound resistance factors and bacterial innoculum determines the risk of surgical infection. Since cautery causes more damage than the scalpel, our hypothesis is that lower numbers of bacteria are required to infect wounds made by electric cautery than to infect wounds made with a scalpel.

Methods: Abdominal fascia was incised in 375 rats by cold knife, cutting current, or coagulation current.

Evaluation of oxygen and pressure in treatment of decompression sickness in guinea pigs.

These experiments examined whether increasing the partial pressure of oxygen (PO2), hydrostatic pressure, or both were responsible for the improvement in effectiveness of recompression treatment previously observed in guinea pigs with increasing depths of air. Unanesthetized male guinea pigs (600-700 g) were subjected to 8.6 atm abs (871 kPa) air dives for 60 min and then decompressed at 1.

Physiologic and perceptual responses to hypercarbia during warm- and cold-water immersion.

Thermoregulatory, respiratory, and perceptual responses to acute CO2 exposure during light exercise (75 W) were assessed in 12 U.S. Navy divers clad only in swim trunks while immersed to the neck in water at 18 degrees and 34 degrees C.

Phorbol esters induce differentiation of human CD34+ hemopoietic progenitors to dendritic cells: evidence for protein kinase C-mediated signaling.

The intracellular signals that mediate the differentiation of pluripotent hemopoietic progenitors to dendritic cells (DC) are largely undefined. We have found that the phorbol ester PMA by itself induced 47% +/- 8.7% of input human CD34+ hemopoietic progenitors to differentiate into cells with morphology and surface Ag phenotype characteristic of DC by day 7 of culture.