Clofazimine for Treatment of Cryptosporidiosis in Human Immunodeficiency Virus Infected Adults: An Experimental Medicine, Randomized, Double-blind, Placebo-controlled Phase 2a Trial.

BACKGROUND: We evaluated the efficacy, pharmacokinetics (PK), and safety of clofazimine (CFZ) in patients living with human immunodeficiency virus (HIV) with cryptosporidiosis. METHODS: We performed a randomized, double-blind, placebo-controlled study. Primary outcomes in part A were reduction in Cryptosporidium shedding, safety, and PK. Primary analysis was according to protocol (ATP). Part B of the study compared CFZ PK in matched individuals living with HIV without cryptosporidiosis. RESULTS: Twenty part A and 10 part B participants completed the study ATP. Almost all part A participants had high viral loads and low CD4 counts, consistent with failure of antiretroviral (ARV) therapy. At study entry, the part A CFZ group had higher Cryptosporidium shedding, total stool weight, and more diarrheal episodes compared with the placebo group. Over the inpatient period, compared with those who received placebo, the CFZ group Cryptosporidium shedding increased by 2.17 log2 Cryptosporidium per gram stool (95% upper confidence limit, 3.82), total stool weight decreased by 45.3 g (P = .37), and number of diarrheal episodes increased by 2.32 (P = .87). The most frequent solicited adverse effects were diarrhea, abdominal pain, and malaise. One placebo and 3 CFZ participants died during the study. Plasma levels of CFZ in participants with cryptosporidiosis were 2-fold lower than in part B controls. CONCLUSIONS: Our findings do not support the efficacy of CFZ for the treatment of cryptosporidiosis in a severely immunocompromised HIV population. However, this trial demonstrates a pathway to assess the therapeutic potential of drugs for cryptosporidiosis treatment. Screening persons living with HIV for diarrhea, and especially Cryptosporidium infection, may identify those failing ARV therapy. CLINICAL TRIALS REGISTRATION: NCT03341767.

Increased intracellular survival of Salmonella Typhimurium ST313 in HIV-1-infected primary human macrophages is not associated with Salmonella hijacking the HIV compartment.

BACKGROUND: Non-typhoidal Salmonella (NTS) causes a severe invasive syndrome (iNTS disease) described in HIV-positive adults. The impact of HIV-1 on Salmonella pathogenesis and the molecular basis for the differences between these bacteria and classical diarrhoeal S. Typhimurium remains unclear. RESULTS: Here, we show that iNTS-associated S. Typhimurium Sequence Type 313 (ST313) bacteria show greater intracellular survival in primary human macrophages, compared with a 'classical' diarrhoeal S. Typhimurium ST19 isolate. The increased intracellular survival phenotype of ST313 is more pronounced in HIV-infected macrophages. We explored the possibility that the bacteria take advantage of the HIV-associated viral-containing compartments created in human macrophages that have low pH. Confocal fluorescence microscopy and focussed ion beam-scanning electron microscopy tomography showed that Salmonella did not co-localise extensively with HIV-positive compartments. CONCLUSION: The capacity of ST313 bacteria to survive better than ST19 bacteria within primary human macrophages is enhanced in cells pre-infected with HIV-1. Our results indicate that the ST313 bacteria do not directly benefit from the niche created by the virus in HIV-1-infected macrophages, and that they might take advantage from a more globally modified host cell. SIGNIFICANCE: A better understanding of the interplay between HIV-1 and Salmonella is important not only for these bacteria but also for other opportunistic pathogens.

Nonspecific effects of oral vaccination with live-attenuated Salmonella Typhi strain Ty21a.

Epidemiological and immunological evidence suggests that some vaccines can reduce all-cause mortality through nonspecific changes made to innate immune cells. Here, we present the first data to describe the nonspecific immunological impact of oral vaccination with live-attenuated Salmonella Typhi strain Ty21a. We vaccinated healthy adults with Ty21a and assessed aspects of innate and adaptive immunity over the course of 6 months. Changes to monocyte phenotype/function were observed for at least 3 months. Changes to innate and adaptive immune cell cytokine production in response to stimulation with vaccine and unrelated nonvaccine antigens were observed over the 6-month study period. The changes that we have observed could influence susceptibility to infection through altered immune responses mounted to subsequently encountered pathogens. These changes could influence all-cause mortality.

Soil organic matter and the extracellular microbial matrix show contrasting responses to C and N availability.

An emerging paradigm in soil science suggests microbes can perform 'N mining' from recalcitrant soil organic matter (SOM) in conditions of low N availability. However, this requires the production of extracellular structures rich in N (including enzymes and structural components) and thus defies stoichiometric expectation. We set out to extract newly synthesised peptides from the extracellular matrix in soil and compare the amino acid (AA) profiles, N incorporation and AA dynamics in response to labile inputs of contrasting C/N ratio. Glycerol was added both with and without an inorganic source of N (10% 15N labelled NH4NO3) to a soil already containing a large pool of refractory SOM and incubated for 10 days. The resulting total soil peptide (TSP) and extracellular pools were compared using colorimetric methods, gas chromatography, and isotope ratio mass spectrometry. N isotope compositions showed that the extracellular polymeric substance (EPS) contained a greater proportion of products formed de novo than did TSP, with hydrophobic EPS-AAs (leucine, isoleucine, phenylalanine, hydroxyproline and tyrosine) deriving substantially more N from the inorganic source provided. Quantitative comparison between extracts showed that the EPS contained greater relative proportions of alanine, glycine, proline, phenylalanine and tyrosine. The greatest increases in EPS-peptide and EPS-polysaccharide concentrations occurred at the highest C/N ratios. All EPS-AAs responded similarly to treatment whereas the responses of TSP were more complex. The results suggest that extracellular investment of N (as EPS peptides) is a microbial survival mechanism in conditions of low N/high C which, from an evolutionary perspective, must ultimately lead to the tendency for increased N returns to the microbial biomass. A conceptual model is proposed that describes the dynamics of the extracellular matrix in response to the C/N ratio of labile inputs.

Biodiesel Co-Product (BCP) Decreases Soil Nitrogen (N) Losses to Groundwater.

This study compares a traditional agricultural approach to minimise N pollution of groundwater (incorporation of crop residues) with applications of small amounts of biodiesel co-product (BCP) to arable soils. Loss of N from soil to the aqueous phase was shown to be greatly reduced in the laboratory, mainly by decreasing concentrations of dissolved nitrate-N. Increases in soil microbial biomass occurred within 4 days of BCP application-indicating rapid adaptation of the soil microbial community. Increases in biomass-N suggest that microbes were partly mechanistic in the immobilisation of N in soil. Straw, meadow-grass and BCP were subsequently incorporated into experimental soil mesocosms of depth equal to plough layer (23 cm), and placed in an exposed netted tunnel to simulate field conditions. Leachate was collected after rainfall between the autumn of 2009 and spring of 2010. Treatment with BCP resulted in less total-N transferred from soil to water over the entire period, with 32.1, 18.9, 13.2 and 4.2 mg N kg-1 soil leached cumulatively from the control, grass, straw and BCP treatments, respectively. More than 99 % of nitrate leaching was prevented using BCP. Accordingly, soils provided with crop residues or BCP showed statistically significant increases in soil N and C compared to the control (no incorporation). Microbial biomass, indicated by soil ATP concentration, was also highest for soils given BCP (p < 0.05). These results indicate that field-scale incorporation of BCP may be an effective method to reduce nitrogen loss from agricultural soils, prevent nitrate pollution of groundwater and augment the soil microbial biomass.

A comparison of two colorimetric assays, based upon Lowry and Bradford techniques, to estimate total protein in soil extracts.

Soil extracts usually contain large quantities of dissolved humified organic material, typically reflected by high polyphenolic content. Since polyphenols seriously confound quantification of extracted protein, minimising this interference is important to ensure measurements are representative. Although the Bradford colorimetric assay is used routinely in soil science for rapid quantification protein in soil-extracts, it has several limitations. We therefore investigated an alternative colorimetric technique based on the Lowry assay (frequently used to measure protein and humic substances as distinct pools in microbial biofilms). The accuracies of both the Bradford assay and a modified Lowry microplate method were compared in factorial combination. Protein was quantified in soil-extracts (extracted with citrate), including standard additions of model protein (BSA) and polyphenol (Sigma H1675-2). Using the Lowry microplate assay described, no interfering effects of citrate were detected even with concentrations up to 5 times greater than are typically used to extract soil protein. Moreover, the Bradford assay was found to be highly susceptible to two simultaneous and confounding artefacts: 1) the colour development due to added protein was greatly inhibited by polyphenol concentration, and 2) substantial colour development was caused directly by the polyphenol addition. In contrast, the Lowry method enabled distinction between colour development from protein and non-protein origin, providing a more accurate quantitative analysis. These results suggest that the modified-Lowry method is a more suitable measure of extract protein (defined by standard equivalents) because it is less confounded by the high polyphenolic content which is so typical of soil extracts.

Assessment of HER2 gene amplification in adenocarcinomas of the stomach or gastroesophageal junction in the INT-0116/SWOG9008 clinical trial.

BACKGROUND: Trastuzumab has been approved for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric carcinoma; however, relatively little is known about the role of HER2 in the natural history of this disease. PATIENTS AND METHODS: Patients enrolled in the INT-0116/SWOG9008 phase III gastric cancer clinical trial with available tissue specimens were retrospectively evaluated for HER2 gene amplification by FISH and overexpression by immunohistochemistry (IHC). The original trial was designed to evaluate the benefit of postoperative chemoradiation compared with surgery alone. RESULTS: HER2 gene amplification rate by FISH was 10.9% among 258 patients evaluated. HER2 overexpression rate by IHC was 12.2% among 148 patients evaluated, with 90% agreement between FISH and IHC. There was a significant interaction between HER2 amplification and treatment with respect to both disease-free survival (DFS) (P = 0.020) and overall survival (OS) (P = 0.034). Among patients with HER2-non-amplified cancers, treated patients had a median OS of 44 months compared with 24 months in the surgery-only arm (P = 0.003). Among patients with HER2-amplified cancers, there was no significant difference in survival based on treatment arm. HER2 status was not a prognostic marker among patients who received no postoperative chemoradiation. CONCLUSION: Patients lacking HER2 amplification benefited from treatment as indicated by both DFS and OS. CLINICAL TRIAL: INT-0116/SWOG9008 phase III.

Review article: the aetiology, investigation and management of diarrhoea in the HIV-positive patient.

BACKGROUND: Diarrhoea is a common presentation throughout the course of HIV disease. AIM: To review the literature relating to aetiology, investigation and management of diarrhoea in the HIV-infected adult. METHODS: The PubMed database was searched using major subject headings 'AIDS' or 'HIV' and 'diarrhoea' or 'intestinal parasite'. The search was limited to adults and to studies with >10 patients. RESULTS: Diarrhoea affects 40-80% of HIV-infected adults untreated with antiretroviral therapy (ART). First-line investigation is by stool microbiology. Reported yield varies with geography and methodology. Molecular and immunological methods and special stains have improved diagnostic yield. Endoscopy is diagnostic in 30-70% of cases of pathogen-negative diarrhoea and evidence supports flexible sigmoidoscopy as a first line screening procedure (80-95% sensitive for CMV colitis), followed by colonoscopy and terminal ileoscopy. Radiology is useful to assess severity, distribution, complications and to diagnose HIV-related malignancies. Side effects and compliance with ART are important considerations in assessment. There is a good evidence base for many specific therapies, but optimal treatment of cryptosporidiosis is unclear and only limited data support symptomatic treatments. CONCLUSIONS: The immunological response to HIV infection and Antiretroviral therapy remains incompletely understood. Antiretroviral therapy regimens need to be optimised to suppress HIV while minimising side effects. Effective agents for management of cryptosporidiosis are lacking. There is an urgent need for enhanced regional diagnostic facilities in countries with a high prevalence of HIV. The ongoing roll-out of Antiretroviral therapy in low-resource settings will continue to change the aetiology and management of this problem, necessitating ongoing surveillance and study.

A let-7 microRNA-binding site polymorphism in 3'-untranslated region of KRAS gene predicts response in wild-type KRAS patients with metastatic colorectal cancer treated with cetuximab monotherapy.

PURPOSE: recent studies have found that KRAS mutations predict resistance to monoclonal antibodies targeting the epidermal growth factor receptor in metastatic colorectal cancer (mCRC). A polymorphism in a let-7 microRNA complementary site (lcs6) in the KRAS 3' untranslated region (UTR) is associated with an increased cancer risk in non-small-cell lung cancer and reduced overall survival (OS) in oral cancers. We tested the hypothesis whether this polymorphism may be associated with clinical outcome in KRAS wild-type (KRASwt) mCRC patients treated with cetuximab monotherapy. PATIENTS AND METHODS: the presence of KRAS let-7 lcs6 polymorphism was evaluated in 130 mCRC patients who were enrolled in a phase II study of cetuximab monotherapy (IMCL-0144). Genomic DNA was extracted from dissected formalin-fixed paraffin-embedded tumor tissue, KRAS mutation status and polymorphism were assessed using direct sequencing and PCR restriction fragment length polymorphism technique. RESULTS: KRAS let-7 lcs6 polymorphism was found to be related to object response rate (ORR) in mCRC patients whose tumors had KRASwt. The 12 KRASwt patients harboring at least a variant G allele (TG or GG) had a 42% ORR compared with a 9% ORR in 55 KRASwt patients with let-7 lcs6 TT genotype (P = 0.02, Fisher's exact test). KRASwt patients with TG/GG genotypes had trend of longer median progression-free survival (3.9 versus 1.3 months) and OS (10.7 versus 6.4 months) compared to those with TT genotypes. CONCLUSIONS: these results are the first to indicate that the KRAS 3'UTR polymorphism may predict for cetuximab responsiveness in KRASwt mCRC patients, which warrants validation in other clinical trials.

Gender-related survival differences associated with polymorphic variants of estrogen receptor-ß (ERß) in patients with metastatic colon cancer.

Estrogen replacement therapy in women has shown a protective effect on the development of colonic carcinomas. Gender-related differences in the development of colonic carcinomas have also been reported. Estrogen receptor-ß (ERß) is expressed in colon carcinomas and has shown prognostic value in colon cancer patients. This study investigated an ERß 3' non-coding polymorphism associated with transcriptional activity to determine clinical outcome in patients with metastatic colon cancer. Genomic DNA from 318 metastatic colon cancer patients, 177 males and 141 females, were collected from 1992 to 2003. These patients were analyzed for CA repeat polymorphism of the ERß gene. Gender-related survival differences were associated with an ERß (CA)n repeat polymorphism (P for interaction=0.003, the likelihood ratio test). Female patients with any short<22 (CA)n repeat alleles had shorter overall survival (OS) compared with female patients who had both long≥22 (CA)n repeat alleles. In the male patients, the opposite OS difference was found. This study supports the role of an ERß (CA)n repeat polymorphism as a prognostic marker in metastatic colon cancer; however, this prognostic factor had opposite implications based on gender.

Polymorphisms in VEGF and IL-8 predict tumor recurrence in stage III colon cancer.

BACKGROUND: Identifying molecular markers for tumor recurrence is critical in successfully selecting patients with stage III colon cancer who are more likely to benefit from adjuvant chemotherapy. The present study analyzed a subset of 10 polymorphisms within eight genes involved in the tumor angiogenesis pathway and their impact on prognosis in stage III colon cancer patients treated with adjuvant chemotherapy. PATIENTS AND METHODS: Blood samples were obtained from 125 patients with locally advanced colon cancer at University of Southern California medical facilities. DNA was extracted from peripheral blood and the genotypes were analyzed using PCR-restriction fragment length polymorphism and 5'-end [gamma-(33)P] ATP-labeled PCR protocols. RESULTS: Polymorphisms in vascular endothelial growth factor (VEGF) (C+936T; P = 0.003, log-rank test) and interleukin-8 (IL-8) (T-251A; P = 0.04, log-rank test) were independently associated with risk of recurrence in stage III colon cancer patients. In combined analysis, grouping alleles into favorable versus nonfavorable alleles, high expression variants of VEGF C+936T and IL-8 T-251A were associated with a higher likelihood of developing tumor recurrence (P < 0.001). CONCLUSION: High expression variants of VEGF C+936T and IL-8 T-251A were associated with shorter time to tumor recurrence, indicating that the analysis of angiogenesis-related gene polymorphisms may help to identify patient subgroups at high risk for tumor recurrence.

The risks associated with short-term placebo-controlled antihypertensive clinical trials: a descriptive meta-analysis.

Short-term (4-8 weeks) placebo-controlled trials are used to evaluate new antihypertensive drug treatment. To evaluate the consequences of such practice, a descriptive meta-analysis was conducted, consisting of blinded review of original case report forms for all patients who died or left a study before its completion for all short-term, placebo-controlled hypertension trials submitted to the Food and Drug Administration from 1973 through 2001. There were 93 marketing applications or supplements involving 590 individual trials that involved 86137 randomized patients (64438 randomized to experimental drug and 21 699 randomized to placebo) with 12658 patient years of observation. There were 9636 dropouts (mean time to dropout was 28 days) and relative risk (RR (placebo/drug))= 1.33 (95% confidence limits, 1.28, 1.39; P < 10(-16)). As expected, lack of blood pressure (BP) control was far more common in patients randomized to placebo; therapeutic failure, RR = 2.53 (2.35, 2.73; P < 10(s15)) and hypertensive emergency, RR = 2.75 (2.19, 3.57; P < 10(-15)). When administrative dropouts and dropouts resulting from inadequate BP control were excluded, the remaining 38% of dropouts were disproportionately more from drug (2810 drug, 816 placebo), RR = 0.80 (0.74, 0.86; P < 10(-8)). There were 43 deaths, RR=0.72 (0.33, 1.45; P=0.37); 40 strokes, RR = 1.43 (0.68, 2.81; P=0.33) and 77 myocardial infarctions, RR=1.06 (0.62, 1.75; P= 0.82). Irreversible harm (a combination of death, stroke and myocardial infarction, 160 total events) was equally distributed between the drug and placebo groups, RR=1.03 (0.71, 1.47; P=0.86).

Invasive Salmonellosis in Malawi

The incidence of invasive salmonellosis has increased among children and HIV-infected adults in Malawi. This has been associated with the emergence of drug resistance in the non-typhoidal Salmonella serovars Enteritidis and Typhimurium. In contrast; S. Typhi isolates have remained fully sensitive to commonly used antibiotics and the estimated incidence of typhoid fever; although still present; has fallen slightly among both adults and children. Infection with S. Typhi is not closely associated with underlying immuno- suppression but it is possible that the non-typhoidal Salmonellae have adapted to the person-person human transmission niche in this frequently immunosuppressed population. The huge burden of invasive salmonellosis in Malawi; the high associated mortality; and the recent emergence of drug resistance emphasise the need for a better understanding of the epidemiology and the need for vaccine development

Are intestinal helminths a risk factor for non-typhoidal Salmonella bacteraemia in adults in Africa who are seropositive for HIV? A case-control study.

In Africa, invasive, non-typhoidal Salmonella (NTS) infections are a common but life-threatening complication in adults who are seropositive for HIV. The high prevalence of human infection with intestinal helminths which penetrate the gut could explain the greater importance of NTS bacteraemia in Africa compared with that in industrialized countries. If helminth infection is a major risk factor for NTS it would provide a locally relevant, public-health target. Intestinal helminth carriage in 57 HIV-positive patients with NTS bacteraemia (the cases) was compared with that in 162 HIV-positive controls who were similar to the cases in terms of age, sex, urban dwelling and socio-economic factors. The prevalence of helminth infection, 29% overall, was lower among the cases (18%) than among the controls (33%), giving a crude odds ratio of 0.40 [with a 95% confidence interval (CI) of 0.21-0.9] and an adjusted odds ratio (aOR) of 0.79 (CI = 0.4-1.8). Five (9%) of the cases and 12 (7%) of the controls were infected with nematodes which penetrate the gut (Ascaris lumbricoides and/or Strongyloides stercoralis). The aOR for infection with these penetrating worms, corrected for age, sex, urban dwelling and phase of study, was 1.40 (CI = 0.4-4.5). The present results do not exclude the possibility that helminths play a role in invasive NTS infections, but are not consistent with helminths being a sufficient risk factor in this population to be a public-health target. Anthelmintics are unlikely to have a major impact on preventing NTS bacteraemia in patients diagnosed HIV-positive in Africa.

Lack of heritability of circulating leptin concentration in humans after adjustment for body size and adiposity using a physiological approach.

OBJECTIVE: To construct a simple physiological model of leptin kinetics, based on measures of body size and composition, which is suitable for investigating the influence of genetic and other influences on circulating leptin levels in humans. METHODS: Consideration of the kinetics of the secretion and clearance of leptin led to a predicted linear relationship between ln(leptin), ln(fat mass), and a function of non-fat body compartments. Results obtained from this model were compared with those from two published empirical models based on adjustment for fat mass alone or for body mass index. Overnight fasted leptin levels, body composition data (dual-energy X-ray absorptiometry) and questionnaire responses were obtained from 527 twin pairs (127 monozygotic, 400 dizygotic; 37 male (age 18-68 y, BMI 18-32 kg/m2), 489 female (age 18-71, BMI 17-44) drawn from the St Thomas' UK Adult Twin Registry. RESULTS: In a partial correlation analysis ln(fat mass) and ln(height) (r=0.80, P<0.0001) and r=-0.22, P<0.0001 respectively) were independent predictors of ln(leptin) in females but ln(lean mass) was not (r=-0.01). A regression model incorporating ln(fat mass), ln(height) and a second order polynomial in age provided an adequate fit of the ln(leptin) data in females (r2=71%). ln(Leptin) values adjusted for body size and composition using the model were not significantly heritable (P=0.11), were significantly related to gender (r2=2.3%) and to ln(insulin) (r2=5.7%), but not to menopausal status (r2=0.7%), hormone replacement therapy (r2=0.4%), past or current smoking (r2=1.1%), or percentage trunk fat (r2=0.5%). Both empirical models found significant heritability (h2=36-42%), overestimated the effect of gender in the data (r2=14-16%), and produced significant relationships between adjusted ln(leptin) and percentage trunk fat (r2=4-12%). CONCLUSIONS: We conclude that our physiologically based model provides an adequate description of the relationship between leptin and body composition and provides a more reliable framework than current empirical approaches for the investigation of other influences on circulating leptin levels. Heritable variations in the control of leptin secretion are unlikely to contribute significantly to variations in leptin levels at the population level.

Three cases of bacteremia caused by Vibrio cholerae O1 in Blantyre, Malawi.

We report three fatal cases of bacteremia (two adults, one neonate) caused by Vibrio cholerae O1 (Ogawa), which occurred in the context of a community outbreak of cholera diarrhea in Blantyre, Malawi. Only four cases of invasive disease caused by V. cholerae O1 have previously been reported. We describe the clinical features associated with these rare cases and discuss their significance.

Bacteraemia and mortality among adult medical admissions in Malawi--predominance of non-typhi salmonellae and Streptococcus pneumoniae.

OBJECTIVES: The high seroprevalence of HIV in Malawi might be expected to alter the pattern of pathogens isolated from bacteraemic patients. We aimed to describe the frequency and seasonal pattern of bacterial isolates from blood, their antibiotic susceptibility, and patient outcome, in order to provide data on which to base empirical antibiotic therapy and further studies of pathogenesis. METHODS: Over a 12-month period, blood cultures were taken from all febrile adult medical admissions to Queen Elizabeth Central Hospital, Blantyre. RESULTS: A total of 2789 out of 9298 adult general medical admissions had blood culture performed, of whom 449 (16.1%) grew significant pathogens. Non-typhi salmonellae (NTS) (37%) and Streptococcus pneumoniae (30%) were the two commonest isolates. Mortality was 18% among general medical admissions and 38% among bacteraemic patients. Mortality for individual pathogens was: NTS 33%; S. pneumoniae 36%; Escherichia coli 54%; Klebsiella spp. 58%; Neisseria meningitidis 44%; Salmonella typhi 17%. Despite an overwhelming association between the major pathogens and HIV infection (95% of S. pneumoniae cases and 92% of NTS cases were seropositive for HIV), a seasonal pattern was preserved. Streptococcus pneumoniae was more frequently isolated in the cold dry months, while STM isolates increased following a rise in temperature. A case of bacteraemia with Vibrio cholerae (serotype 01) was detected during a cholera outbreak in the rainy season. Although S. pneumoniae isolates were relatively susceptible to penicillin (88%) and chloramphenicol (74%), S. typhimurium isolates were fully susceptible only to chloramphenicol. CONCLUSIONS: This large study confirms the dominance of NTS and S. pneumoniae in bacteraemia in an area affected by HIV-1 and allows comparison of mortality by individual pathogens. It demonstrates a preserved seasonal pattern of bacteraemia for these major pathogens, despite an overwhelming association with HIV infection.

Magnitude of microelectrode refinement in pallidotomy and thalamotomy.

The relative accuracy of starting point algorithms in microelectrode-guided stereotactic pallidotomy and thalamotomy was evaluated using postoperative magnetic resonance imaging (MRI) data. Multiplanar reformations were performed to align postoperative MRI in anterior-posterior, dorsal-ventral and mediolateral planes. Three-dimensional distance and direction from the pallidal and thalamic stereotactic starting points to the respective radiofrequency lesions were measured. Similar magnitude of microelectrode refinement in pallidotomy and thalamotomy suggested similar accuracy of algorithms used to set the stereotactic starting point. Fewer microelectrode-recording tracts were required to identify optimal lesioning sites in thalamotomy compared to pallidotomy. Lesions were consistently localized anterior and superior to the starting point and a refined starting point algorithm may reduce the number of microelectrode recording tracts.

Iron status and stores decline with age in Lewis rats.

In the context of a larger study examining the interaction of vitamin A (VA) status and age on immune function, we examined age-related changes in hematologic and iron status variables in male Lewis rats. Animals were fed a nutritionally adequate purified diet containing either 0.35 (marginal), 4.0 (control) or 50 (supplemented) mg retinol equivalents (as retinyl palmitate) per kg of diet from the time of weaning until killing at 8-10 (middle-aged) or 20-22 (old) mo of age. Neither VA nor VA and age interaction effects were significant for most iron variables examined. After controlling for body weight, old rats had significantly lower hemoglobin, hematocrit and plasma iron than middle-aged rats. This decrease in hematologic and transport iron variables was not accompanied by a shift of iron into other storage compartments. Old rats also had significantly lower total iron content and iron concentration in liver, spleen and bone marrow. Hemosiderin iron in marrow smears correlated significantly (r = 0.43-0.76, P: < 0.05) with chemical estimates of iron in storage, transport and functional pools. Old rats also tended to have less stained iron in femur marrow smears. Thus, body iron in functional, transport and storage compartments, namely the liver, spleen and bone marrow, were significantly lower in old than in middle-aged rats. Although iron stores and status are usually considered to increase with advancing age, our data show a consistent pattern of lower hematologic and storage iron variables in old than in middle-aged Lewis rats. Future research is indicated to understand the biology and functional consequences of the observed age-associated decline in body iron.

Bacterial meningitis in Malawian adults: pneumococcal disease is common, severe, and seasonal.

We prospectively collected laboratory details and outcome data on all patients with laboratory-confirmed cases of meningitis that presented to our unit in Blantyre, Malawi, from 1 April 1998 through 31 March 1999. There were 502 patients with cases of meningitis; the most common causative organisms were Cryptococcus neoformans and Streptococcus pneumoniae. This pattern probably reflects the local human immunodeficiency virus (HIV) seroprevalence (31%) and is different from the pattern in 1974, when Neisseria meningitidis was the most common isolate. There has been an 8-fold increase in the number of meningitis cases per year since 1974, and a doubling of the percentage of medical admissions due to meningitis. The inpatient mortality rate among patients with cases of pneumococcal meningitis was 61%, and in the group as a whole was 41%. Despite the HIV-related pattern of infecting pathogens among these cases of meningitis and the increased incidence of the condition, there was evidence that the typical seasonal pattern of pneumococcal meningitis, which peaks in the cold, dry season, was preserved.