Transfer Learning-Based Condition Monitoring of Single Point Cutting Tool.

Machining activities in recent times have shifted their focus towards tool life and tool wear. Cutting tools have been utilized on a daily basis and play a vital role in manufacturing industries. Prolonged and incessant operation of the cutting tool can lead to wear and tear of the component, thereby compromising the dimensional accuracy. The condition of a tool is estimated based upon the surface quality of the machined component, condition of the machine, and the rate of production. Maintaining the tool health plays a vital role in enhancing the productivity of manufacturing industries. Numerous efforts were experimented by the researchers to maintain the tool health condition. The drawbacks of conventional diagnostic techniques include requirement of high level of human intelligence and professional expertise on the field, which led the researchers to develop intelligent and automatic diagnostic tools. There are many techniques suggested by researchers to detect the condition of single point cutting tool. This article proposes the use of transfer learning technology to detect the condition of single point cutting tool. First, the vibration signals were collected from the cutting tool and plots were made which will work as input to the deep learning algorithms. The deep learning algorithms have the capability to learn from the plots of vibration signals and classify the state of the single point cutting tool. In this work, the pretrained networks such as VGG-16, AlexNet, ResNet-50, and GoogLeNet were employed to identify the state of the cutting tool. In the pretrained networks, the effect of hyperparameters such as batch size, solver, learning rate, and train-test split ratio was studied, and the best performing network was suggested for tool condition monitoring.

Misfire Detection in Spark Ignition Engine Using Transfer Learning.

Misfire detection in an internal combustion engine is an important activity. Any undetected misfire can lead to loss of fuel and power in the automobile. As the fuel cost is more, one cannot afford to waste money because of the misfire. Even if one is ready to spend more money on fuel, the power of the engine comes down; thereby, the vehicle performance falls drastically because of the misfire in IC engines. Hence, researchers paid a lot of attention to detect the misfire in IC engines and rectify it. Drawbacks of conventional diagnostic techniques include the requirement of high level of human intelligence and professional expertise in the field, which made the researchers look for intelligent and automatic diagnostic tools. There are many techniques suggested by researchers to detect the misfire in IC engines. This paper proposes the use of transfer learning technology to detect the misfire in the IC engine. First, the vibration signals were collected from the engine head and plots are made which will work as input to the deep learning algorithms. The deep learning algorithms have the capability to learn from the plots of vibration signals and classify the state of the misfire in the IC engines. In the present work, the pretrained networks such as AlexNet, VGG-16, GoogLeNet, and ResNet-50 are employed to identify the misfire state of the engine. In the pretrained networks, the effect of hyperparameters such as back size, solver, learning rate, and train-test split ratio was studied and the best performing network was suggested for misfire detection.

Systemic Amyloid A Amyloidosis in Island Foxes (Urocyon littoralis): Severity and Risk Factors.

Systemic amyloid A (AA) amyloidosis is highly prevalent (34%) in endangered island foxes (Urocyon littoralis) and poses a risk to species recovery. Although elevated serum AA (SAA) from prolonged or recurrent inflammation predisposes to AA amyloidosis, additional risk factors are poorly understood. Here we define the severity of glomerular and medullary renal amyloid and identify risk factors for AA amyloidosis in 321 island foxes necropsied from 1987 through 2010. In affected kidneys, amyloid more commonly accumulated in the medullary interstitium than in the glomeruli (98% [n= 78 of 80] vs 56% [n= 45], respectively;P< .0001), and medullary deposition was more commonly severe (19% [n= 20 of 105]) as compared with glomeruli (7% [n= 7];P= .01). Univariate odds ratios (ORs) of severe renal AA amyloidosis were greater for short- and long-term captive foxes as compared with free-ranging foxes (ORs = 3.2, 3.7, respectively; overall P= .05) and for females as compared with males (OR = 2.9;P= .05). Multivariable logistic regression revealed that independent risk factors for amyloid development were increasing age class (OR = 3.8;P< .0001), San Clemente Island subspecies versus San Nicolas Island subspecies (OR = 5.3;P= .0003), captivity (OR = 5.1;P= .0001), and nephritis (OR = 2.3;P= .01). The increased risk associated with the San Clemente subspecies or captivity suggests roles for genetic as well as exogenous risk factors in the development of AA amyloidosis.

Pooled effect of injection pressure and turbulence inducer piston on performance, combustion, and emission characteristics of a DI diesel engine powered with biodiesel blend.

In this study, the effect of injection pressure on combustion, performance, and emission characteristics of a diesel engine powered with turbulence inducer piston was studied. Engine tests were executed using conventional diesel and 20% blend of adelfa biodiesel [A20]. The results acquired from renewable fuel A20 in the conventional engine showed reduction in brake thermal efficiency being the result of poor air fuel mixing characteristics and the higher viscosity of the tested fuel. This prompted further research aiming at the improvement of turbulence for better air fuel mixing by a novel turbulence inducer piston [TIP]. The investigation was carried out to study the combined effect of injection pressure and turbulence inducer piston. Considerable improvement in the emission characteristics like hydrocarbon, carbon monoxide, smoke was acheived as a result of optimised injection pressure. Nevertheless, the nitrogen oxide emissions were slightly higher than those of the conventional unmodified engine. The engine with turbulence inducer piston shows the scope for reducing the major pollution and thus ensures environmental safety.

Effect of hydrogen on ethanol-biodiesel blend on performance and emission characteristics of a direct injection diesel engine.

Environment issue is a principle driving force which has led to a considerable effort to develop and introduce alternative fuels for transportation. India has large potential for production of biofuels like biodiesel from vegetable seeds. Use of biodiesel namely, tamanu methyl ester (TME) in unmodified diesel engines leads to low thermal Efficiency and high smoke emission. To encounter this problem hydrogen was inducted by a port fueled injection system. Hydrogen is considered to be low polluting fuel and is the most promising among alternative fuel. Its clean burning characteristic and better performance attract more interest compared to other fuels. It was more active in reducing smoke emission in biodiesel. A main drawback with hydrogen fuel is the increased NOx emission. To reduce NOx emission, TME-ethanol blends were used in various proportions. After a keen study, it was observed that ethanol can be blended with biodiesel up to 30% in unmodified diesel engine. The present work deals with the experimental study of performance and emission characteristic of the DI diesel engine using hydrogen and TME-ethanol blends. Hydrogen and TME-ethanol blend was used to improve the brake thermal efficiency and reduction in CO, NOx and smoke emissions.

Amelioration of cisplatin-induced nephrotoxicity in rats by tetramethylpyrazine, a major constituent of the Chinese herb Ligusticum wallichi.

Nephrotoxicity of the anticancer drug, cisplatin (CP) involves enhanced renal generation of reactive oxygen metabolites and lipid peroxidation caused by decreased levels of antioxidants and antioxidant enzymes. Tetramethylpyrazine (TMP) is known to act as a strong antioxidant. Therefore, in the present work, we aimed at testing the possible protective or palliative effect of TMP on CP nephrotoxicity in rats. TMP was given orally at a dose of 80 mg . kg(- 1) . day(- 1) for 7 days. Some of these rats were given a single intraperitoneal injection of CP (or vehicle) at a dose of 6 mg/kg on Day 6 of treatment. Animals were sacrificed 6 days after CP (or vehicle) treatment, and blood, urine, and kidneys were obtained. Nephrotoxicity was assessed biochemically by measuring creatinine and urea in serum, reduced glutathione (GSH) concentration in renal cortex, by urinalysis, and histopathologically by light microscopy. CP significantly increased the concentration of urea and creatinine (P < 0.05) by about 128% and 170%, respectively; increased urine volume and N-acetyl-beta-D-glucosaminidase (NAG) activity; and significantly decreased osmolality and protein concentrations. CP treatment reduced GSH by about 34% (P < 0.05) and superoxide dismutase (SOD) and total antioxidant activity (TOX) by about 28% and 21%, respectively (P < 0.05). TMP pretreatment significantly mitigated all of these effects. Sections from saline- and TMP-treated rats showed apparently normal proximal tubules. However, kidneys of CP-treated rats had a moderate degree of necrosis. This was markedly reduced when CP was given after pretreatment with TMP. CP cortical concentration was not significantly altered by TMP treatment. The results suggest that TMP ameliorated the histological, physiological, and biochemical indices of nephrotoxicity in rats. Pending further pharmacological and toxicological studies, TMP may potentially be useful as a nephroprotective agent.

Effects of age on composition and quality of muscle Longissimus thoracis of the Omani Arabian camel (Camelus dromedaries).

The aim of this study was to determine the effects of age on chemical composition and quality characteristics of the Arabian one-humped camel's meat. Samples of longissimus thoracis (between the 10th and the 13th rib of the left side) were randomly collected from 21 Omani intact male camels of three different age groups: group 1 (1-3 years), group 2 (3-5 years) and group 3 (6-8 years). Samples were chilled (1-3°C) for 48h. Moisture, crude protein, fat and ash were determined on freeze dried ground muscle. Mineral contents were determined using an Inductively coupled plasma emission spectrometer (ICP). Meat quality including ultimate muscle pH, Warner-Bratzler shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss percent, and colour L(∗), a(∗), b(∗) were measured using standard methods. The moisture, protein, fat and ash ranged from 64.4% to 76.7%; 18.6% to 25.0%, 1.1% to 10.5% and 1.0% to 1.4% on dry matter basis, respectively. The Ca, Mg, Na, K, P, Cad, Cr, Ni, Pb, Co, Mo, Be and V ranged from, 9.2 to 46.6, 24.7 to 57.3, 104.7 to 257.0, 471.4 to 1053.0, 249.9 to 584.0, 0.005 to 0.024, 0.020 to 0.410, 0.016 to 0.187, 0.010 to 0.299, 0.010 to 0.018, 0.050 to 0.470, 0.005 to 0.030 and 0.013 to 0.141mg/100g on dry matter basis, respectively. The percentage of protein decreased and that of fat increased with increasing camel age. The ultimate pH, shear force, sarcomere length, fragmentation index, expressed juice, cooking loss, lightness (L(∗)), redness (a(∗)) and yellowness (b(∗)) ranged from 5.46 to 6.64, 4.25 to 17.82, 0.96 to 2.50, 55.91 to 94.81,19.50 to 33.63, 13.18 to 29.88, 27.86 to 43.21, 10.46 to 22.81, and 4.63 to 10.11, respectively. Muscles of younger camels (group 1) had significantly (P<0.05) lower shear force value, ultimate pH and higher sarcomere length, fragmentation index, expressed juice, cooking loss, and lightness color (L(∗)) by 48%, 3.4%, 43%, 25%, 28%, 14%, and 16% than those collected from older camels (group 3), respectively. Values of middle age camels (group 2) camels were in-between. This study confirmed that camel meat is healthy and nutritious as it contains low fat as well as being a good source of minerals. Age is an important factor in determining meat quality and composition.

The effects of replacing Rhodes grass (Chloris gayana) hay with ghaf (Prosopis cineraria) pods on the performance of Omani native sheep.

A feeding trial using various levels of dry pods of ghaf (Prosopis cineraria) was carried out with 28 Omani native male sheep. Individual feed intake and body weight were determined for 50 days to allow assessment of the effects of the feeds on growth, feed intake, feed conversion and carcase measurements. The ripened ghaf pods contained 91% dry matter (DM), 13.5% crude protein (CP), 14.3% crude fibre (CF), 1.3% ether extract (EE) and 5.2% ash (on DM basis). Four levels of ghaf (0, 15%, 30% and 45%) were used with corresponding decreasing proportions of Rhodes grass (RGH) hay. Animals fed rations containing RGH as the sole source of roughage and no ghaf grew faster (135 g/day) and had better feed conversion than those fed various levels of ghaf. Sheep fed 15% ghaf gained reasonably well (90 g/day) and had carcase attributes similar to those fed no ghaf. Sheep fed 30% ghaf still gained weight but those fed 45% ghaf lost weight. Negative effects on growth appeared to occur after 6 weeks of feeding ghaf.

Risk factors for admission and the role of respiratory syncytial virus-specific cytotoxic T-lymphocyte responses in children with acute bronchiolitis.

BACKGROUND: Risk factors for admission of children with acute bronchiolitis have remained controversial. Technological advances in the measurements of cytotoxic T-lymphocyte (CTL) activity, enable respiratory syncytial virus (RSV)-specific CTL activity to be studied in infants with bronchiolitis for the first time. We evaluated risk factors for admission of children with acute bronchiolitis and determined the role of CTL responses in those infected with RSV. METHOD: Children between 3 and 24 months of age presenting with bronchiolitis to the paediatric outpatient department at King Edward VIII Hospital, Durban, over a 1-year period were enrolled. Management included clinical evaluation, nasopharyngeal aspiration, standard treatment and hospitalisation if indicated. Secretions were tested with monoclonal antibodies for RSV and pooled respiratory viruses; shell vial cultures were also established. Permission was requested from parents of RSV-infected subjects for blood draws for specific cytotoxic T-cell assays and CD4/CD8 cells on admission and repeat CTL on day 7. RESULTS: Viruses were identified in 55 of the 114 subjects studied (48.2%). RSV was seen in 41 cases (74.5%). Twenty-three infants (20.2%) required admission. Risk factors associated with inpatient admissions on univariate analysis included younger mean age (7.6 months v. 10.1 months), overcrowding (p < 0.01) and indoor exposure to products of combustion of cooking fuels (p = 0.05). Only the former two were significant on multivariate analysis. RSV-specific CTL responses were obtained in 21 children (51.2%). Responses were either very weak (N = 7) or negative (N = 14) on day 0 and did not alter significantly on day 7. The mean CD4/CD8 ratios in this group were 2.27:1. The highest frequency of CTL was directed against the proteins M4/5/6', with counts ranging from 100 to 400 spot forming cells (sfc)/million. CONCLUSION: Measures to address risk factors identified in this study may decrease the need for hospitalisation from bronchiolitis. The lack of RSV-specific CTL responses in peripheral blood of immunocompetent RSV-infected children suggest an alternative method of induction of immunity or compartmentalisation of immune cells.

Fatty acid composition of muscle and fat tissues of Omani Jebel Akhdar goats of different sexes and weights.

This paper describes the fatty acid (FA) composition of muscle and fat tissue in Omani Jebel Akhdar buck, wether and does slaughtered at 11, 18 or 28 kg body weight (BW). The fat percentage in dry matter (DM) of the subcutaneous and kidney fats ranged between 85 and 98% and that of muscle ranged between 17 and 21%. Subcutaneous fat tended to have lower DM than kidney fat. Palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids comprised the largest proportions of FA in the muscle tissue (approximately 80%) with oleic acid being the most abundant. Ninety-one percent of the total FA were contributed by the C16 and C18 fatty acids being 31.6 and 58.5%, respectively. C19 and C20 were not detected in the muscle tissue. The essential FA, C20:2, C20:3 and C20:4 contributing about 1%. Muscle tissue of the Jebel Akhdar goat contained an average 51.3% and 48.7% of saturated (SFA) and unsaturated fatty acids (UFA), respectively. Polyunsaturated FA (PUFA) constituted about 5% and monounsaturated (MFA) 43.5% of the total FA. Subcutaneous fat contained more total FA (68.08%) than kidney fat (48.14%) in the whole tissue. Kidney fat contained higher percentages of C16 and C18 but less C:18:1 than subcutaneous fat. The proportions of SFA to UFA was high in both fat depots with the SFA being much higher in the kidney than subcutaneous fats. C16, C18 and C:18:1c acids comprised 64.2 and 78% and C16s and C18s made up 81 and 85% of total FA in subcutaneous and kidney fats, respectively. In both subcutaneous and kidney fats, there was a trend of increasing values of DM and fat percentage with intact males having the lowest and females the highest values. Males had higher levels of C15, C18:2 and C18:3 but lower levels of C17, C18 and total C16, C18 and C18:1 in muscle tissue. Intact males had higher levels of C10, 12, 15 FA but lower C16:1 and C16+18+18:1 than others in subcutaneous fat. Intact males had a similar trend for C12 and 14 but lower SFA and higher UFA in kidney fat. There was a trend of increasing DM and fat% in dry matter with increasing body weight. C10, 12 and 14 of the kidney fat decreased with increasing slaughter weight. There was a trend of the two C16 FA decreasing and the four C18 increasing with BW in the kidney fat. This resulted in proportions of the total C16 and C18 FA increasing from 81.8 to 86.8%. These findings confirm those of other studies on goat meat quality that, as judged by fatty acid composition it is not inferior to that of meats from other farm animals.

Effects of age on fatty acid composition of the hump and abdomen depot fats of the Arabian camel (Camelus dromedarius).

This study aimed to quantify concentrations of fatty acids in the hump and abdomen fats of three different age groups of camel. Hump and abdomen fats were extracted from eight each of one-humped camels (Camelus dromedarius) of three age groups: group 1 (<1 year old), group 2 (1-3 years old) and group 3 (>3 years old). The fatty acid methyl ester concentrations of these fats were determined by gas-liquid chromatography (GLC). The percentage of fat in the hump (H) and abdomen (A) fats was significantly (P<0.05) lower for group 1 (H 92.0% and A 94.3%) than for group 2 (H 97.4% and A 97.2%) and group 3 (H 97.6% and A 97.5%), on a dry matter basis. Hump and abdomen fats from the three different groups had similar fatty acid patterns with more saturated than unsaturated fatty acids. The saturated fatty acids in the hump fats accounted for 58.3, 67.6, and 63.0% of the total fatty acids for groups 1, 2 and 3, respectively; group 1 had significantly (P<0.05) lower saturated and higher unsaturated fatty acid concentrations than group 2. The iodine numbers were significantly (P<0.05) higher in group 1 than either group 2 or 3. Palmitic acid (C16:0) was the major fatty acid in hump fat with 32.06, 32.90 and 34.37%, followed by oleic acid (C18:1) 33.65, 21.66 and 28.91.0% and stearic acid (C18:0) 18.85, 24.13 and 20.74% for groups 1, 2 and 3, respectively. Group 1 had significantly higher (P<0.05) oleic acid and lower stearic acid concentrations than group 2. The melting point of both hump and abdomen fats varied between the age groups. This study indicated that age has an effect on the fatty acid composition and the melting point of hump and abdomen fats in one-humped Arabian camels.

NF-kappaB is involved in the regulation of CD154 (CD40 ligand) expression in primary human T cells.

Cognate interactions between CD154 (CD40 ligand, CD40L) on activated T cells and its receptor CD40 on various antigen-presenting cells are involved in thymus-dependent humoral immune responses and multiple other cell-mediated immune responses. We have studied the regulation of CD154 expression in human T cells after activation with anti-CD3 and anti-CD28 antibodies or after pharmacological activation of protein kinase C with phorbol 12-myristate 13-acetate, and the calcium ionophore ionomycin. Under these conditions, transcription of the CD154 gene was rapidly induced without requiring de novo protein synthesis. Pharmacological inhibitors of NF-kappaB activation down-regulated CD154 mRNA and protein levels. Cyclosporin A, an inhibitor of NF-AT activation, acted similarly, and the effects of both inhibitors were additive. A potential NF-kappaB binding site is present within the CD154 promoter at positions -1190 to - 1181. In electrophoretic mobility shift assays, this sequence was specifically bound by NF-kappaB present in nuclear extracts from activated T cells. Furthermore, in transient co-transfection of Jurkat T cells, p65 activated the transcription of a reporter construct containing a multimer of this NF-kappaB binding site. These observations demonstrate a role of NF-kappaB transcription factors in the regulation of CD40L expression in activated primary human T cells.

Anterior spinal decompression in HIV-positive patients with tuberculosis. A prospective study.

total of 39 HIV-infected adults with spinal tuberculosis underwent anterior spinal decompression for neurological deficit. Fresh-frozen allografts were used in 38 patients. Antituberculous drugs were prescribed for 18 months, but antiretroviral therapy was not used. Six patients died within two years of surgery. Neurological recovery and allograft incorporation were observed at follow-up at a mean of 38 months, although the CD4/CD8 ratios were reversed in all patients. Adequate preoperative nutritional support and compliance with antituberculous treatment are essential in ensuring a satisfactory outcome.

Nutritional evaluation of solar dried sardines as a ruminant protein supplement.

Solar dried sardines of various qualities were analyzed for nutrient content and for nutrient digestibility and nitrogen balance in sheep. Additionally, key serum enzymes and metabolites were examined to identify potential toxic effects. Dried sardine protein, ether extract and crude ash content ranged from 65 to 39%, 5.7 to 5.1%, and 22 to 51%, respectively, for high to low quality dried sardines. Visual appraisal of the dried sardines did not appear to be very reliable for determining dried sardine quality. Crude protein content was highly correlated (r(2)=0.962) with crude ash content based on the following equation (dry matter basis): crude protein%=86.0 - (0.961xcrude ash%). Therefore, crude ash could be used to estimate crude protein content and dried sardine quality. Digestibility in Omani sheep was determined on diets composed of a composite of dried sardines collected from Al-Batinah region of the Sultanate (the average crude protein content was 51%) and compared to that of a similar diet using soybean meal (also 51% crude protein) as the major protein source. The digestibility of crude protein, ether extract, total carbohydrates, digestible energy and metabolizable energy in diets utilizing dried sardines versus the soybean meal diet were 74 versus 76%, 69 versus 68%, 67 versus 69%, 64 versus 66%, and 52 versus 56%, respectively. Although, protein digestibility was similar, nitrogen balance data suggested that nitrogen in the dried sardine diet was not as efficiently utilized as nitrogen in the soybean meal diet. Key serum enzymes and metabolites did not suggest that dried sardines at 10% of the total dietary intake would cause metabolic disturbances in sheep. The study suggests that solar dried sardines may be effectively used in ruminant diets but may not have the protein by-pass value of commercial, processed fish meals.

Rapid definition of five novel HLA-A*3002-restricted human immunodeficiency virus-specific cytotoxic T-lymphocyte epitopes by elispot and intracellular cytokine staining assays.

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) play a major role in control of viral replication. To understand the contribution of this antiviral response, an initial step is to fully define the specific epitopes targeted by CTL. These studies focused on CTL responses restricted by HLA-A*3002, one of the HLA-A molecules most prominent in African populations. To avoid the time-consuming effort and expense involved in culturing CTL prior to defining epitopes and restricting alleles, we developed a method combining Elispot assays with intracellular gamma interferon staining of peripheral blood mononuclear cells to first map the optimal epitopes targeted and then define the HLA restriction of novel epitopes. In two A*3002-positive subjects whose CTL responses were characterized in detail, the strongest response in both cases was to an epitope in p17 Gag, RSLYNTVATLY (residues 76 to 86). Using this method, CTL epitopes for which there were no motif predictions were optimized and the HLA restriction was established within 48 to 72 h of receipt of blood. This simple and convenient approach should prove useful especially in the characterization of CTL responses specific to HIV and other viruses, particularly in localities where performing cytotoxicity assays would be problematic.

Evaluation of efficacy and safety of nimesulide with betacyclodextrin vs nimesulide tablets in osteoarthritis.

Efficacy and safety of nimesulide as well as favourable tolerability have been tested in osteoarthritis in short term study and post-marketing survey. Here is a report which shows the superiority of nimesulide complexed with betacyclodextrin vs ninesulide tablet in osteoarthritis in a long term study.

Functionally inert HIV-specific cytotoxic T lymphocytes do not play a major role in chronically infected adults and children.

The highly sensitive quantitation of virus-specific CD8(+) T cells using major histocompatibility complex-peptide tetramer assays has revealed higher levels of cytotoxic T lymphocytes (CTLs) in acute and chronic virus infections than were recognized previously. However, studies in lymphocytic choriomeningitis virus infection have shown that tetramer assays may include measurement of a substantial number of tetramer-binding cells that are functionally inert. Such phenotypically silent CTLs, which lack cytolytic function and do not produce interferon (IFN)-gamma, have been hypothesized to explain the persistence of virus in the face of a quantitatively large immune response, particularly when CD4 help is impaired. In this study, we examined the role of functionally inert CTLs in chronic HIV infection. Subjects studied included children and adults (n = 42) whose viral loads ranged from <50 to >100,000 RNA copies/ml plasma. Tetramer assays were compared with three functional assays: enzyme-linked immunospot (Elispot), intracellular cytokine staining, and precursor frequency (limiting dilution assay [LDA]) cytotoxicity assays. Strong positive associations were observed between cell numbers derived by the Elispot and the tetramer assay (r = 0.90). An even stronger association between tetramer-derived numbers and intracellular cytokine staining for IFN-gamma was present (r = 0.97). The majority (median 76%) of tetramer-binding cells were consistently detectable via intracellular IFN-gamma cytokine staining. Furthermore, modifications to the LDA, using a low input cell number into each well, enabled LDAs to reach equivalence with the other methods of CTL enumeration. These data together show that functionally inert CTLs do not play a significant role in chronic pediatric or adult HIV infection.

Spinal tuberculosis in HIV positive and negative patients: immunological response and clinical outcome.

We measured cytokine secretion patterns in peripheral blood and granulation tissue by flow cytometry in 16 human immunodeficiency virus (HIV) positive and 26 HIV negative patients with spinal tuberculosis. Anti-retroviral therapy was not prescribed. There were no significant differences in the postoperative morbidity and neurological recovery between the two groups.

Role of cerebrospinal fluid shunting for human immunodeficiency virus-positive patients with tuberculous meningitis and hydrocephalus.

OBJECTIVE: Tuberculous meningitis (TBM) and its complications continue to have devastating neurological consequences for patients. Budgetary constraints, especially in developing countries, have made it necessary to select patients for shunting who are likely to experience good recoveries. To date, the value of cerebrospinal fluid shunting for human immunodeficiency virus (HIV)-positive patients with TBM has not been clearly established. METHODS: Thirty patients with TBM and hydrocephalus were prospectively evaluated. Coincidentally, one-half of the patients were HIV-positive. All patients underwent uniform treatment, including ventriculoperitoneal shunt placement and antituberculosis treatment. CD4 counts were measured for all patients. Outcomes were assessed at 1 month. RESULTS: No complications related to shunt insertion were noted. The HIV-positive group fared poorly (death, 66.7%; poor outcome, 64.7%), compared with the HIV-negative group (death, 26.7%; poor outcome, 30.8%). Despite cerebrospinal fluid shunting, no patient in the HIV-positive group experienced a good recovery (Glasgow Outcome Scale score of 5). This is in contrast to the six patients (40%) in the HIV-negative group who, with the same treatment, experienced good recoveries (Glasgow Outcome Scale scores of 5) at discharge (P<0.14). No patient (either HIV-positive or HIV-negative) who presented in TBM Grade 4 survived, whereas no HIV-positive patient who presented in TBM Grade 3 survived. A significant relationship was noted between CD4 counts and patient outcomes (P<0.031). CONCLUSION: In the absence of obvious clinical benefit, HIV-positive patients with TBM should undergo a trial of ventricular or lumbar cerebrospinal fluid drainage, and only those who exhibit significant neurological improvement should proceed to shunt surgery.

Differential narrow focusing of immunodominant human immunodeficiency virus gag-specific cytotoxic T-lymphocyte responses in infected African and caucasoid adults and children.

Cytotoxic T-lymphocyte (CTL) activity plays a central role in control of viral replication and in determining outcome in cases of human immunodeficiency virus type 1 (HIV-1) infection. Incorporation of important CTL epitope sequences into candidate vaccines is, therefore, vital. Most CTL studies have focused upon small numbers of adult Caucasoid subjects infected with clade-B virus, whereas the global epidemic is most severe in sub-Saharan African populations and predominantly involves clade-C infection in both adults and children. In this study, sensitive enzyme-linked immunospot (elispot) assays have been utilized to identify the dominant Gag-specific CTL epitopes targeted by adults and children infected with clade-B or -C virus. Cohorts evaluated included 44 B-clade-infected Caucasoid American and African American adults and children and 37 C-clade-infected African adults and children from Durban, South Africa. The results show that 3 out of 46 peptides spanning p17(Gag) and p24(Gag) sequences tested contain two-thirds of the dominant Gag-specific epitopes, irrespective of the clade, ethnicity, or age group studied. However, there were distinctive differences between the dominant responses made by Caucasoids and Africans. Dominant responses in Caucasoids were more often within p17(Gag) peptide residues 16 to 30 (38 versus 12%; P < 0.01), while p24(Gag) peptide residues 41 to 60 contained the dominant Gag epitope more often in the African subjects tested (39 versus 4%; P < 0.005). Within this 20-mer p24(Gag), an epitope presented by both B42 and B81 is defined which represents the dominant Gag response in >30% of the total infected population in Durban. This epitope is closely homologous with dominant HIV-2 and simian immunodeficiency virus Gag-specific CTL epitopes. The fine focusing of dominant CTL responses to these few regions of high immunogenicity is of significance to vaccine design.