Outbreak of invasive methicillin-resistant Staphylococcus aureus infection associated with acupuncture and joint injection

OBJECTIVE

To describe an outbreak of invasive methicillin-resistant Staphylococcus aureus (MRSA) infection after percutaneous needle procedures (acupuncture and joint injection) performed by a single medical practitioner.

SETTING

A medical practitioner's office and 4 hospitals in Perth, Western Australia.

PATIENTS

Eight individuals who developed invasive MRSA infection after acupuncture or joint injection performed by the medical practitioner.

METHODS

We performed a prospective and retrospective outbreak investigation, including MRSA colonization surveillance, environmental sampling for MRSA, and detailed molecular typing of MRSA isolates. We performed an infection control audit of the medical practitioner's premises and practices and administered MRSA decolonization therapy to the medical practitioner.

RESULTS

Eight cases of invasive MRSA infection were identified. Seven cases occurred as a cluster in May 2004; another case (identified retrospectively) occurred approximately 15 months earlier in February 2003. The primary sites of infection were the neck, shoulder, lower back, and hip: 5 patients had septic arthritis and bursitis, and 3 had pyomyositis; 3 patients had bacteremia, including 1 patient with possible endocarditis. The medical practitioner was found to be colonized with the same MRSA clone [ST22-MRSA-IV (EMRSA-15)] at 2 time points: shortly after the first case of infection in March 2003 and again in May 2004. After the medical practitioner's premises and practices were audited and he himself received MRSA decolonization therapy, no further cases were identified.

CONCLUSIONS

This outbreak most likely resulted from a breakdown in sterile technique during percutaneous needle procedures, resulting in the transmission of MRSA from the medical practitioner to the patients. This report demonstrates the importance of surveillance and molecular typing in the identification and control of outbreaks of MRSA infection.

Serotonin persistently activates the extracellular signal-related kinase in sensory neurons of Aplysia independently of cAMP or protein kinase C

Activation of the extracellular signal-related kinase is important for long-term increases in synaptic strength in the Aplysia nervous system. However, there is little known about the mechanism for the activation of the kinase in this system. We examined the activation of Aplysia extracellular signal-related kinase using a phosphopeptide antibody specific to the sites required for activation of the kinase. We found that phorbol esters led to a prolonged activation of extracellular signal-related kinase in sensory cells of the Aplysia nervous system. Surprisingly, inhibitors of protein kinase C did not block this activation. Serotonin, the physiological transmitter involved in long-term synaptic facilitation, also led to prolonged activation of extracellular signal-related kinase, but inhibitors of protein kinase A or protein kinase C did not block this activation. We examined whether the protein synthesis-dependent increase in excitability stimulated by phorbol esters was dependent on phorbol ester activation of extracellular signal-related kinase, but increases in excitability were still seen in the presence of inhibitors of extracellular signal-related kinase activation. Our results suggest that prolonged phosphorylation of extracellular signal-related kinase in the Aplysia system is not mediated by either of the classic second messenger activated kinases in this system, protein kinase A or protein kinase C and that extracellular signal-related kinase is not important for phorbol ester induced long-term effects on excitability.

Regulation of eukaryotic initiation factor 4E phosphorylation in the nervous system of Aplysia californica

We have used an antibody that specifically recognizes eukaryotic initiation factor 4E (eIF4E) when it is phosphorylated at Ser(207) to characterize eIF4E phosphorylation in the nervous system of APLYSIA: The level of phosphorylated eIF4E, but not the level of total eIF4E, was significantly correlated with the basal rate of translation measured from different animals. Serotonin (5-HT), a transmitter that regulates the rate of translation in APLYSIA: neurons, had mixed effects on eIF4E phosphorylation. 5-HT decreased eIF4E phosphorylation in sensory cell clusters through activation of protein kinase C. 5-HT increased eIF4E phosphorylation in the whole pleural ganglia. In the APLYSIA: nervous system, eIF4E phosphorylation correlated with phosphorylation of the p38 MAP kinase, but not the p42 MAP kinase (ERK). Furthermore, an inhibitor of the p38 MAP kinase significantly decreased basal eIF4E phosphorylation, but an inhibitor of the MAP or ERK kinase (MEK) did not. Despite the correlation of eIF4E phosphorylation with the basal rate of translation, inhibition of eIF4E phosphorylation by an inhibitor of the p38 MAP kinase did not significantly decrease the rate of translation.

Protein kinase C phosphorylated at a conserved threonine is retained in the cytoplasm

Phosphorylation of calcium-activated protein kinase Cs (PKCs) at threonine 634 and/or threonine 641 increases during long term potentiation or associative learning in rodents. In the marine mollusk Aplysia, persistent activation of the calcium-activated PKC Apl I occurs during long term facilitation. We have raised an antibody to a peptide from PKC Apl I phosphorylated at threonines 613 and 620 (sites homologous to threonines 634 and 641). This antibody recognizes PKC Apl I only when it is phosphorylated at threonine 613. Both phorbol esters and serotonin increase the percentage of kinase phosphorylated at threonine 613 in Aplysia neurons. Furthermore, the pool of PKC that is phosphorylated at threonine 613 in neurons is resistant to both membrane translocation and down-regulation. Replacement of threonine 613 with alanine increased the affinity of PKC Apl I for calcium, suggesting that phosphorylation of this site may reduce the ability of PKC Apl I to translocate to membranes in the presence of calcium. We propose that phosphorylation of this site is important for removal of PKC from the membrane and may be a mechanism for negative feedback of PKC activation.

Disseminated infection due to Nocardia transvalensis coincident with Cryptococcus neoformans variety gattii meningitis

A case of meningitis due to Cryptococcus neoformans var. gattii coincident with disseminated Nocardia transvalensis infection is reported. Nocardia infection initially progressed despite high-dose antimicrobial therapy. Although a specific immunologic defect could not be defined, in vitro lymphocyte proliferation in response to stimulation with the Nocardia isolate was reduced. It is proposed that coinfection with Cryptococcus neoformans may have contributed to the observed impairment of lymphocyte function, leading to disseminated Nocardia disease and a suboptimal treatment response.

The effect of Plasmodium falciparum malaria on HIV-1 RNA blood plasma concentration

OBJECTIVES

This study was undertaken to determine the relative effect of malaria infection on HIV concentration in blood plasma, and prospectively to monitor viral concentrations after antimalarial therapy.

DESIGN

A prospective, double cohort study was designed to compare the blood HIV-1 RNA concentrations of HIV-positive individuals with and without acute malaria illness. Subjects were followed for 4 weeks after successful malaria therapy, or for 4 weeks from enrollment (controls).

METHODS

Malawian adults with symptomatic Plasmodium falciparum parasitemia (malaria group) and asymptomatic, aparasitemic blood donors (control group) were tested for HIV-1 antibodies to identify appropriate study groups. The malaria group received antimalarial chemotherapy only and were followed with sequential blood films. In both groups, blood plasma HIV-1 RNA viral concentrations were determined at enrollment and again at 1, 2 and 4 weeks.

RESULTS

Forty-seven malaria patients and 42 blood donors were enrolled. At enrollment blood plasma HIV-1 RNA concentrations were approximately sevenfold higher in patients with malaria than in blood donors (medians 15.1 x 10(4) and 2.24 x 10(4) copies/ml, respectively, P = 0.0001). No significant changes in median HIV-1 concentrations occurred in the 21 blood donors followed to week 4 (P = 0.68). In the 27 subjects successfully treated for malaria who were followed to week 4, a reduction in plasma HIV-1 RNA was observed from a median of 19.1 x 10(4) RNA copies/ml at enrollment, to 12.0 x 10(4) copies/ml at week 4, (P = 0.02). Plasma HIV-1 concentrations remained higher in malaria patients than controls (median 12.0 x 10(4) compared with 4.17 x 10(4) copies/ml, P = 0.086).

CONCLUSIONS

HIV-1 blood viral burden is higher in patients with P. falciparum malaria than in controls and this viral burden can, in some patients, be partly reduced with antimalarial therapy.

Comparison of NucliSens and Roche Monitor assays for quantitation of levels of human immunodeficiency virus type 1 RNA in plasma

We compared the performance of Organon Teknika's NucliSens and Roche Diagnostic Systems' Monitor quantitative human immunodeficiency type 1 RNA assays. Both had similar linearity and sensitivity over most of the dynamic range of the assays, although the Monitor assay was superior at the low range of RNA values while the NucliSens assay was more consistent at higher RNA values. NucliSens generally showed less interassay variability.

Phosphorylation of eIF4E at a conserved serine in Aplysia

We have cloned eIF4E from the marine mollusk, Aplysia californica. The sequence of eIF4E from Aplysia is more similar to vertebrate eIF4Es than to other invertebrate sequences. Aplysia eIF4E is encoded by two tissue-specific RNAs. Antibodies raised to the carboxyl terminus of eIF4E recognize a 29-kDa protein that can bind to 7-methyl-GTP caps. The phosphorylation site identified in mammalian eIF4E is conserved in the Aplysia homologue, and an Aplysia eIF4E fusion protein is phosphorylated well by both Aplysia protein kinase C isoforms. However, protein kinase C phosphorylates both Ser-207 and Thr-208 in vitro, while only Ser-207 is phosphorylated in vivo. We have confirmed that Ser-207 is phosphorylated in vivo by raising a phosphopeptide antibody to this site. This antibody will be useful in determining the signal transduction pathways leading to eIF4E phosphorylation in Aplysia.

Enterovirus associated neurological disease in an HIV-1 infected man

We report a case of relapsing multifocal neurological disease associated with CNS echovirus 6 infection in an HIV-1-infected individual with no evidence of immunoglobulin deficiency. The illness was initially characterized by optic and cranial neuropathies and myelopathy; concurrent granulomatous hepatitis suggested disseminated viral infection. Treatment with combination nucleoside analogues led to partial remission, but a demyelinating polyneuropathy subsequently developed. There was improvement and sustained remission in the polyneuropathy following treatment with intravenous immunoglobulin. Neurotropic enterovirus infection may be involved in the pathogenesis of certain HIV-associated neurological syndromes.

High levels of human immunodeficiency virus type 1 in blood and semen of seropositive men in sub-Saharan Africa

High levels of human immunodeficiency virus type 1 (HIV-1) replication, as reflected in HIV-1 RNA concentrations in blood and semen, probably contribute to both rapid disease progression and enhanced sexual transmission. Semen and blood were collected from 49 Malawian and 61 US and Swiss (US/Swiss) HIV-1-seropositive men with similar CD4 cell counts and no urethritis or exposure to antiretroviral drugs. Median seminal plasma and blood plasma HIV-1 RNA concentrations were >3-fold (P = .034) and 5-fold (P = .0003) higher, respectively, in the Malawian men. Similar differences were observed in subsets of the Malawian and US/Swiss study groups matched individually for CD4 cell count (P = .035 and P < .002, respectively). These observations may help explain the high rates of HIV-1 sexual transmission and accelerated HIV-1 disease progression in sub-Saharan Africa.

Association of CD4 cell depletion and elevated blood and seminal plasma human immunodeficiency virus type 1 (HIV-1) RNA concentrations with genital ulcer disease in HIV-1-infected men in Malawi

CD4 cell counts and blood plasma and seminal plasma human immunodeficiency virus type 1 (HIV-1) concentrations were compared in HIV-1 RNA-seropositive men with urethritis and with or without genital ulcer disease (GUD). GUD was associated with lower CD4 cell counts (median, 258 vs. 348/microL) and increased blood plasma HIV-1 RNA (median, 240 x 10[3] vs. 79.4 x 10[3] copies/mL). Men with nongonococcal urethritis and GUD shed significantly greater quantities of HIV-1 in semen (median, 195 x 10[3] vs. 4.0 x 10[3] copies/mL) than men with nongonococcal urethritis without GUD. These levels decreased approximately 4-fold following antibiotic therapy. The results indicate an association between GUD and increased blood HIV-1 RNA levels. Increased HIV-1 in semen was demonstrated in some men with GUD; such an increase could lead to increased transmission, thus complicating interpretation of the role of the genital ulcer itself in the infectiousness of HIV. Reasons for increased HIV RNA in semen in men with GUD remain to be determined.

The hypothalamic-pituitary-adrenocortical axis in severe falciparum malaria: effects of cytokines

Patients with malaria can have features of adrenal insufficiency. Because of the pathophysiological and clinical implications of an Addisonian state, the hypothalamic-pituitary-adrenocortical axis was assessed in nine Vietnamese adults with complicated malaria. A CRH test was performed on admission (in convalescence in five cases) and in six healthy controls. Basal plasma ACTH concentrations in the patients and controls were similar [median (range): 2.9 (0.2-9.7) vs. 3.5 (1.9-13.4) pmol/L, respectively; P > 0.1]. Serum cortisol levels were greater in the patients [882 (294-1682) vs. 190 (110-676) nmol/L; P < 0.01], but three (33%) had values within the control range. Basal serum corticosteroid-binding globulin concentrations were similar in patients and controls (P = 0.23). The post-CRH rise in plasma ACTH was attenuated in the patients [peak: 6.1 (0.9-23.2) vs. 14.5 (6.2-21.5) pmol/L in controls; P < 0.05]; basal and peak plasma ACTH correlated with plasma interleukin-6 in this group (rs > or = 0.60; P < or = 0.04). Serum cortisol responses to CRH were depressed in acute illness [peak 990 (394-1, 805) nmol/L or 10 (0-50%) above baseline vs. 500 (429-703) nmol/L or 160 (10-380%) in controls; P < 0.05]. The median estimated serum cortisol t1/2 was 4.6 h in the patients and 1.6 h in the controls. These data suggest that, relative to a normal stress response, primary and secondary adrenal insufficiency can occur in severe malaria but may be attenuated by increased circulating interleukin-6 concentrations and impaired cortisol metabolism. The benefits of stress-dose corticosteroid replacement are unknown but could be considered in hypoglycemic patients or those with a serum cortisol within or below the reference range.

Effect of antiviral treatment on the shedding of HIV-1 in semen

OBJECTIVE

The potential role of antiretroviral treatment on the infectiousness of HIV-1-infected men was examined by studying the effect of antiviral treatment on the shedding of HIV-1 in semen.

METHODS

Forty-four patients enrolled in various treatment protocols were asked to donate a semen sample before they began a new antiviral treatment and at a follow-up visit after 6 to 15 weeks of treatment. Since most patients were on blinded protocols, patients were stratified by response of blood viral load. The effect of each patient's treatment was classified as good (n = 24), fair (n = 8) and marginal (n = 13) by measurement of the HIV RNA reduction in blood plasma (> 1.0 log10; 0.5-1.0 log10 and < 0.5 log10 HIV RNA copies/ml reduction, respectively). The effect of treatment on shedding of HIV-1 in semen was documented by the reduction of HIV RNA concentration in seminal plasma and by quantitative HIV-1 seminal cell culture.

RESULTS

Overall, antiviral treatment resulted in a significant fall in the viral load in semen (RNA and culture) that paralleled the reduction of viral load in blood. More pronounced reductions of HIV RNA in semen were observed as the effectiveness of treatment on blood HIV RNA levels increased (median drop from baseline 0, 0.3 log10 and 0.8 log10 RNA copies/ml in patients with marginal, fair and good treatment effect, respectively). Thirteen patients lost detectable HIV RNA in blood on treatment and all of these had undetectable levels of HIV-1 in semen by culture and RNA analysis at follow-up. In 19 of the 31 patients (62%) who still had HIV RNA in their blood during treatment, semen HIV levels were below detection in semen at follow-up.

CONCLUSIONS

Treatment-induced changes of HIV RNA concentration in blood are generally associated with a corresponding change in seminal HIV RNA: If confirmed in larger studies, potent antiretroviral therapy might reduce the spread of HIV-1.

Reduction of concentration of HIV-1 in semen after treatment of urethritis: implications for prevention of sexual transmission of HIV-1. AIDSCAP Malawi Research Group

BACKGROUND

Transmission of HIV-1 is predominantly by heterosexual contact in sub-Saharan Africa, where sexually transmitted diseases (STDs) are also common. Epidemiological studies suggest that STDs facilitate transmission of HIV-1, but the biological mechanism remains unclear. We investigated the hypothesis that STDs increase the likelihood of transmission of HIV-1 through increased concentration of the virus in semen.

METHODS

HIV-1 RNA concentrations were measured in seminal and blood plasma from 135 HIV-1-seropositive men in Malawi; 86 had urethritis and 49 controls did not have urethritis. Men with urethritis received antibiotic treatment according to the guidelines of the Malawian STD Advisory Committee. Samples were analysed at baseline and at week 1 and week 2 after antibiotic therapy in urethritis patients, and at baseline and week 2 in the control group.

FINDINGS

HIV-1-seropositive men with urethritis had HIV-1 RNA concentrations in seminal plasma eight times higher than those in seropositive men without urethritis (12.4 vs 1.51 x 10(4) copies/mL, p = 0.035), despite similar CD4 counts and concentrations of blood plasma viral RNA. Gonorrhoea was associated with the greatest concentration of HIV-1 in semen (15.8 x 10(4) copies/mL). After the urethritis patients received antimicrobial therapy directed against STDs, the concentration of HIV-1 RNA in semen decreased significantly (from 12.4 x 10(4) copies/mL to 8.91 x 10(4) copies/mL at 1 week [p = 0.03] and 4.12 x 10(4) copies/mL at 2 weeks [p = 0.0001]). Blood plasma viral RNA concentrations did not change. There was no significant change in seminal plasma HIV-1 RNA concentrations during the 2-week period in the control group (p = 0.421).

INTERPRETATION

These results suggest that urethritis increases the infectiousness of men with HIV-1 infection. HIV-1-control programmes, which include detection and treatment of STDs in patients already infected with HIV-1, may help to curb the epidemic. Targeting of gonococcal urethritis may be a particularly effective strategy.

Effects of reverse transcriptase inhibitor therapy on the HIV-1 viral burden in semen

HIV-1 infection continues to spread worldwide, primarily through sexual intercourse. Because semen is a major vehicle for transmission of HIV-1, we evaluated the effects of reverse transcriptase inhibitor therapy on the amount of HIV-1 in semen. The semen and blood of 11 HIV-1-infected men (i.e. treatment group) were collected before the initiation of reverse transcriptase inhibitor therapy and then 8 to 18 weeks after initiation of therapy. The semen and blood of another 11 HIV-1-infected men (i.e., longitudinal group), who were not on or had no change in antiretroviral therapy for at least 2 months before study entry, were collected at approximately 2-week intervals for 10 to 26 weeks. In the treatment group, 82% of the seminal plasma HIV-1 RNA levels decreased from baseline after 8 to 18 weeks of therapy (median reduction of 1.01 log10, p = 0.01), and 100% of the blood plasma RNA levels decreased from baseline over the same period (median reduction of 0.92 log10, p = 0.003). Five of these patients were followed for at least 52 weeks and had a median seminal plasma HIV-1 RNA level of 0.66 log10 below baseline at 1 year. All subjects in the treatment group with positive cultures at baseline (50%) had negative cultures or a lower infectious units per ejaculate at the 8- to 18-week follow-up examinations. The HIV-1 RNA levels in blood and semen of the longitudinal group did not change significantly over 10 to 26 weeks. Initiation of reverse transcriptase inhibitor therapy effectively reduces shedding of HIV-1 in semen and may therefore reduce the spread of infection within populations.

Cloning and tissue distribution of the Aplysia Na+ channel alpha-subunit cDNA

Voltage-gated Na+ channels generate the depolarizing inward current that is critical for the initiation and conduction of action potentials. To study the roles of Na+ channels in neuronal signaling, we have begun the molecular analysis of Na+ channels in Aplysia californica. We have isolated cDNAs that encode a neuronal Na+ channel alpha-subunit, which we have named SCAP1. DNA sequence analysis of the SCAP1 cDNA revealed an open reading frame that predicts a protein of 1,993 amino acids, which is highly similar to other members of the Na+ channel alpha-subunit gene family. RNase protection assays carried out on various Aplysia tissues indicated that SCAP1 is expressed predominantly in the nervous system. All of the nonneuronal tissues tested were negative with the exceptions that low levels of expression were observed in ovotestis and parapodium, probably due to the presence of small numbers of neurons within these tissue preparations. Southern blot hybridization at reduced stringency indicated that the genome of Aplysia contains more than one Na+ channel alpha-subunit gene.

Cloning and characterization of aplycalcin and Aplysia neurocalcin, two new members of the calmodulin superfamily of small calcium-binding proteins

We report here the sequences of two new proteins from Aplysia, aplycalcin and Aplysia neurocalcin. These proteins belong to a family of calcium-binding proteins, found primarily in vertebrate brain and retina, that have been proposed to play a role in calcium-dependent regulation of enzymes in signal transduction pathways. Like other members of this family, the Aplysia proteins have consensus sequences for myristoylation, bind calcium, and translocate from cytosol to membrane when the calcium level is raised above the resting intracellular concentration. Both proteins are relatively enriched in Aplysia nervous system, but are also found to a significant degree in other tissues. The expression of mRNA for these proteins in Aplysia nervous tissue is regulated during development, roughly paralleling the reported emergence of several forms of synaptic plasticity. The messages are present at low levels in stage 11, show a large increase by late stage 12, and decline to a plateau of approximately 30% of the peak value afterward. On the basis of the properties of these proteins and by analogy with proposed functions of some of the retinal homologues, we suggest that these proteins may play a role in mediating calcium-dependent processes in neuronal function. The presence of both proteins in other tissues may suggest analogous roles for the proteins in other cell types.

Quantitation of human immunodeficiency virus type 1 RNA in cell free seminal plasma: comparison of NASBA with Amplicor reverse transcription-PCR amplification and correlation with quantitative culture

Human immunodeficiency virus type 1 (HIV-1) is transmitted by infected males in semen. However, the inoculum required for infection is unknown. The ability to collect such information will rely on the availability of reliable quantitative assays of HIV-1 in semen. We examined the comparative performance of NASBA and Amplicor Monitor RT-PCR in quantifying HIV-1 RNA in cell free seminal plasma from seropositive men and correlated the results obtained with viral titres measured by a seminal cell quantitative microculture (QMC) assay. Of samples analysed, 68% and 56% by both NASBA and RT-PCR contained measurable HIV-1 RNA, respectively. Amplification inhibition frequently affected RT-PCR but not NASBA. Excluding samples with complete RT-PCR inhibition, there was 90% qualitative concordance and a strong positive correlation (r = 0.86) of RNA levels measured by the two methods. Comparison of the concentration of HIV-1 RNA in seminal plasma samples, as measured by NASBA, with QMC viral titres indicated that RNA levels probably reflect the infectiousness of whole semen. NASBA is a reliable technique for quantitating HIV-1 RNA in seminal plasma and should become a valuable tool in the study of factors that influence the sexual transmission of HIV.

Clustered voltage-gated Na+ channels in Aplysia axons

Clustering of voltage-gated Na+ channels is critical for the fast saltatory conduction of action potentials in vertebrate myelinated axons. However, the mechanisms responsible for the generation and maintenance of Na+ channel clustering are not well understood. In this study we have raised an antibody against the cloned SCAP-1 voltage-gated Na+ channel of the marine invertebrate Aplysia californica and used it to examine Na+ channel localization in Aplysia ganglia and in cultured Aplysia sensory neurons. Our results show that there is a large cytoplasmic pool of Na+ channels in the soma of Aplysia neurons. Furthermore, we show that Na+ channels in Aplysia axons are not homogeneously distributed but, rather, are present in distinct clusters. Theoretical considerations indicate that Na+ channel clustering may enhance action potential conduction. We propose that clustered Na+ channels may be a fundamental property of many axons, and perhaps of many membranes that conduct Na(+)-dependent action potentials.

The metabolism of platelet-activating factor in severe and cerebral malaria

In order to examine the effects of platelet-activating factor (PAF) in complicated Plasmodium falciparum infections, plasma concentrations of lyso-PAF, stable metabolite and principal precursor of PAF, were measured in 25 Vietnamese adults with severe malaria. The concentration of PAF in the cerebrospinal fluid (CSF) was determined in a sub-group of 23 comatose patients and, together with that of lyso-PAF, in the plasma of 20 patients on recovery of consciousness. The concentration of lyso-PAF in the plasma was depressed on admission to hospital (median [range]; 21 [8-143] vs. 293 [215-410] ng/ml in 10 controls; P < 0.001). There was, however, no change in plasma activity of acetylhydrolase which converts PAF to lyso-PAF (P > 0.01 vs. controls) while simultaneous reduction in the concentration of lipoproteins associated with lyso-PAF were less than those of lyso-PAF per se in the plasma. The plasma concentration of lyso-PAF on admission was associated with parasitaemia and the concentration of serum triglycerides (rs = -0.42, P = 0.04 in each case), the latter being consistent with hepatic effects of PAF reported in previous studies. CSF concentrations of PAF on admission were low (2.3 [0.5-7.7] vs. 0.9 [0-2.5] ng/ml after recovery, P < 0.01) compared with values reported previously in bacterial meningitis. Plasma concentrations of lyso-PAF after recovery lay between admission and control values. While increased availability of PAF may reflect parasite burden and may modulate liver-mediated metabolic disturbances such as hypoglycaemia and lactic acidosis, the role of PAF in cerebral malaria is uncertain.

Mineral homoeostasis in acute renal failure complicating severe falciparum malaria

Disturbances in calcium metabolism in acute renal failure (ARF) remain incompletely understood. Most data are from patients with rhabdomyolysis. As renal impairment commonly accompanies severe malaria in the absence of rhabdomyolysis, falciparum malaria provides an alternative model of mineral homoeostasis in ARF. We studied 25 Vietnamese subjects, aged 18-63 yr, with severe malaria and 10 controls. Fourteen patients had a serum creatinine level of 250 mumol/L or less during treatment (group 1), five developed ARF but were not dialyzed (group 2a), and six required dialysis (group 2b). Group 1 patients presented with mild hypocalcemia (mean +/- SD serum ionized calcium, 1.18 +/- 0.05 vs. 1.23 +/- 0.02 mmol/L in controls; P = 0.01) that persisted until discharge in the presence of normal serum phosphate, PTH, and vitamin D metabolite levels. Group 2 patients were more hypocalcemic on admission (1.10 +/- 0.08 mmol/L; P < 0.0001 vs. controls), especially those in group 2b whose serum ionized calcium fell to 0.88 +/- 0.13 mmol/L when renal dysfunction was maximal. In group 2 patients, the admission serum PTH level was raised (5.4 +/- 3.8 vs. 2.7 +/- 0.9 pmol/L in controls; P < 0.02) and changed reciprocally with calcemia. Significant rises in serum phosphate occurred only in group 2b patients who had depressed serum free 1,25-dihydroxyvitamin D levels throughout. Hypercalcemia did not accompany the diuretic phase of ARF. These data suggest that parathyroid gland dysfunction is a cause of hypocalcemia in severe malaria without ARF, as seen in group 1 patients; in patients with ARF, the effect of the combination of phosphate retention and altered vitamin D metabolism on skeletal PTH sensitivity is of prime significance.

Cerebral mass lesions due to cytomegalovirus in patients with AIDS: report of two cases

Cytomegalovirus (CMV) is an increasingly important opportunistic pathogen in patients with HIV infection and advanced immune deficiency. Neurological complications due to CMV cause significant morbidity but may be treatable with specific anti-viral therapy: cerebral mass lesions are not a generally recognised manifestation. We report two patients with CMV encephalitis presenting as a cerebral mass lesion, with simultaneous occurrence of a pleuro-pulmonary mass also caused by CMV in one case, and with concurrent polyradiculomyelopathy in the other. The spectrum of previously reported clinical and radiological features of CNS involvement in AIDS is discussed. CMV should be considered in the differential diagnosis of cerebral mass lesions in patients with HIV infection and severe immune deficiency so that anti-viral therapy can be rapidly deployed.

Serum vitamin A and E concentrations in acute falciparum malaria: modulators or markers of severity?

1. To assess the association between vitamin A, vitamin E and the clinical course of severe malaria, serial morning blood samples were taken from 24 Vietnamese patients, aged 18-62 years, receiving intensive treatment for complicated Plasmodium falciparum infections. A single fasting blood sample was also taken from 10 control subjects aged 22-45 years. Serum retinol, carotene and vitamin E concentrations were measured by h.p.l.c. 2. Admission serum retinol concentration was depressed relative to that of the control subjects (0.69 +/- 0.35 versus 1.86 +/- 0.41 mumol/l mean +/- SD, P < 0.001) and correlated inversely with indices of hepatic function, but positively with the simultaneous serum creatinine concentration (P < 0.05). During the first week of treatment, serum retinol concentration increased in parallel with improving liver function, whereas serum creatinine concentration remained elevated in the majority of patients. Serum alpha- and beta-carotene concentrations remained depressed throughout. 3. Serum vitamin E concentration, corrected for total serum cholesterol concentration in the form of a ratio, was also depressed at presentation (3.1 +/- 1.8 x 10(3) versus 4.2 +/- 0.8 x 10(3) in control subjects; P < 0.05), but tended to be higher than the control value at the time of discharge (0.1 > P > 0.05); there was a significant correlation between admission ratio and parasite clearance time (P = 0.04). 4. On the basis of this and previous studies, vitamin A replacement could be considered in selected severely ill patients without renal impairment. As found previously in animal models, depressed vitamin E levels may have a beneficial effect on the course of malarial infection.

The pharmacokinetics and pharmacodynamics of quinine in the diabetic and non-diabetic elderly

1. Quinine is a front-line antimalarial drug but is prescribed most commonly in nonmalarious countries for cramps. Postural hypotension, hearing loss and hyperinsulinaemic hypoglycaemia occur in malaria and overdose but little is known of quinine kinetics and toxicity in the elderly. 2. We studied 12 non-insulin-dependent diabetics and 10 non-diabetic controls aged 51-79 years. Subjects attended on two occasions > 7 days apart. On each test day, subjects were given a 600 Cal meal at 18.00 h (0 h) and, on one occasion, quinine sulphate 600 mg at 22.00 h (4 h). Venous blood samples for glucose, insulin and quinine assay were drawn pre-prandially and then regularly over the next 38 h. Supine and erect blood pressures were taken and audiometry was performed at 4, 6, 8 and 14 h. A one-compartment open pharmacokinetic model was fitted to serum quinine concentrations. 3. Absorption and elimination half-times, volume of distribution and oral clearance of quinine were comparable in the two groups (P > 0.2) and there was a mean absorption lag-time of approximately 1 h. Basal and immediate post-prandial (< 4 h) serum glucose and insulin concentrations on both test days were similar in the diabetics and also in the non-diabetics, but quinine produced a mean reduction in serum glucose of 1.0 mmol l-1 from 3-5 h post-dose in both groups without affecting serum insulin concentrations. Quinine administration did not alter postural blood pressure changes or produce significant hearing loss in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary essential fatty acids change the fatty acid profile of rat neural mitochondria over time

This experiment examined the time course over which the amount of dietary essential fatty acids (EFA) affects brain mitochondrial fatty acids. Weanling rats were fed 20% (wt/wt) fat diets that contained either 4 or 15% (wt/wt of diet) EFA for 1, 2, 3 or 6 wk or a 10% EFA diet for 3 or 6 wk. The EFA ratio [18:2(n-6)/18:3(n-3)] of all diets was approximately 30. Fatty acid analysis of brain mitochondrial phosphatidylethanolamine, phosphatidylcholine and cardiolipin revealed that the largest dietary effect was on 18:2(n-6), which was 30% higher in rats fed the 15 vs. 4% EFA diets after 1 wk. This difference increased to twofold by 3 wk and was still twofold after 6 wk. These results demonstrate several facts: 1) the response of 18:2(n-6) in cardiolipin to dietary EFA is very fast and large, relative to changes in other quantitatively major fatty acids observed in weanling rats; 2) the 18:2(n-6) level in neural cardiolipin stabilizes after 3 wk of feeding at a level dependent upon the amount of dietary EFA; and 3) at least one neural fatty acid, 18:2(n-6), is very sensitive to amounts of dietary EFA that are well above the animal's EFA requirement.

Neural 22-carbon fatty acids in the weanling rat respond rapidly and specifically to a range of dietary linoleic to alpha-linolenic fatty acid ratios

Changing the dietary ratio of the essential fatty acids (EFA), 18:2n6 and 18:3n3, while keeping the amounts of other fatty acids in the diet constant can rapidly and specifically alter the proportions of n6 and n3 22-carbon fatty acids in the brain of the weanling rat. A dietary 18:2n6/18:3n3 ratio of 165 versus 1.8 caused higher n6 and lower n3 22-carbon fatty acid levels, without changing total 22-carbon fatty acid levels, in phosphatidylethanolamine and phosphatidylcholine from several neural membrane fractions. This was apparent after only 2 weeks and showed no sign of plateauing after 12 weeks. Other neural fatty acids were essentially unaffected. The three most abundant 22-carbon fatty acids responded somewhat differently to increments in the dietary 18:2n6/18:3n3 ratio (1.8, 9, 36, and 165). Levels of 22:4n6 increased by similar absolute amounts for each four-fold increase in dietary 18:2n6/18:3n3 ratio; in contrast, the largest absolute changes in 22:5n6 and 22:6n3 levels occurred as the 18:2n6/18:3n3 ratio increased from 36 to 165. This study shows that the 18:2n6/18:3n3 ratio of diets high in fat (40% of energy) and adequate in EFA, both typical of diets in developed countries, can substantially and relatively quickly affect the 22-carbon fatty acids in the brain, even after the rapid accumulation of these fatty acids during neural growth has ceased.

The effects of diet and duration of diabetes on hypermethioninemia in streptozotocin-diabetic rats

There are conflicting reports concerning the existence of severe hypermethioninemia in rats made diabetic with the pancreotoxin, streptozotocin. To determine whether this discrepancy is due to experimental differences in the severity of diabetes or the diet fed to the animals, streptozotocin-diabetic and control rats were fed either a casein-based semipurified diet or laboratory chow for 2 or 5 weeks. Plasma methionine concentrations were elevated six- to nine-fold after 2 weeks in the casein-fed diabetics compared with both their own controls and the chow-fed diabetics, respectively. Circulating methionine levels had declined sharply by 5 weeks in the casein-fed diabetics but were still more than twice those of the casein-fed control and chow-fed diabetic levels. Since methionine intakes were only 30% greater in the casein-fed diabetics than in the chow-fed diabetics, it is unlikely that this is the sole cause of the large differences in plasma methionine levels. The reason for the difference in circulating Met levels could not be explained on the basis of overall amino acid availability, since growth, nitrogen balance, and plasma large neutral amino acid profiles (excluding Met) were similar within control and diabetic groups fed the two diets.

A long-term nutrition intervention experience: lipid responses and dietary adherence patterns in the Multiple Risk Factor Intervention Trial

Nutrition counselors in the Multiple Risk Factor Intervention Trial (MRFIT) were able to help middle-aged men who were at high risk for coronary heart disease change their dietary habits, maintain those changes over time, and decrease their serum cholesterol levels. Most of a 7.5% mean serum cholesterol reduction achieved after 6 years of nutrition intervention occurred during the first year of the trial and was thereafter sustained. Total cholesterol and low-density lipoprotein cholesterol fraction decreases indicated improvement in terms of coronary heart disease risk. The food record rating, a numerical, semi-objective adherence technique that assesses a 3-day food record with respect to lipid-lowering potential, was used throughout the trial to measure adherence to recommended food patterns. Participants with lower food record rating scores, which indicate better adherence, demonstrated greater reductions in serum total cholesterol, plasma total cholesterol, and low-density lipoprotein fraction cholesterol determinations on a group basis. Subjective evaluations of the suitability of home and working environments, evidence of deviation from the MRFIT food patterns, and overall nutrition program motivation also showed that as ratings in each category became more favorable, lower food record rating scores and greater blood lipid reductions were consistently observed. The subgroup of participants who were non-smokers and not hypertensive demonstrated greater lipid responses and better dietary adherence. Continued smoking and antihypertensive medications appeared to adversely influence dietary adherence and/or lipid reductions. The MRFIT experience, however, demonstrated for the first time that dietary changes and blood lipid reductions can be achieved after the initial intervention effect, despite a continued emphasis on high blood pressure management and smoking cessation.

MFP versus stannous fluoride mouthrinses for prevention of decalcification in orthodontic patients

Twenty-two orthodontic patients in the eleven to fifteen-year age-group participated in a one-year fluoride rinsing program. A 0.1 percent SnF2 solution was compared to a MFP solution containing an equivalent amount of fluoride. A laboratory study evaluated the enamel solubility reducing capacities of the two solutions. Enamel solubility reduction by a two-minute treatment with 0.1 percent SnF2 was 77.8 percent; that for MFP solution was only 13.1 percent. Rinsing daily with SnF2 prevented decalcification completely in twelve patients; two of ten patients rinsing with MFP developed new decalcification during orthodontic treatment. Thus, SnF2 was more effective than MFP in both the laboratory and clinical phases of the study. These results support the requirement for frequent applications, if patients are at advanced risk, and suggest that the method of treatment is at least as important as the choice of specific fluoride.