A comparison of the ball rebound characteristics of wooden and composite cricket bats at three approach speeds

The primary aim of this study was to compare the rebound characteristics of wooden and composite cricket bats. The rebound characteristics of two 'experimental' bats manufactured from composite material were compared with three English willow bats and one Kashmir willow bat. The bats were tested using a specially designed testing rig, which propelled a 156 g Kookaburra cricket ball at three impact speeds: fast-medium, 67 km x h(-1); fast, 101 km x h(-1); and express, 131 km x h(-1) on to the bats mounted in position so that the ball impacts occurred at the position where the blade of the bats was the thickest. The rebound characteristics of the bats were calculated by measuring the approach and rebound speeds of the ball as it passed through a light beam positioned a short distance away from the point of impact. The statistical software package SAS was used to test for significant differences (p < 0.05) between the average rebound characteristics of the bats. Further, Scheffé's method was used as a post hoc comparison to determine whether differences existed between the composite and willow bats. When the composite and traditional willow bats were compared, the results showed no significant differences between the three average approach speeds, while the composite bats showed significantly smaller rebound speeds and coefficient of restitution at all three approach speeds. Thus, the rebound characteristics of the composite bats were significantly less than the traditionally designed English willow wooden bats and would not enhance performance by allowing the batsman to hit the ball harder, assuming all other factors, such as bat speed, mass distribution and the impact point, were the same for the bats. Further study is required to determine the physical properties of composite and wooden bats to enhance their impact characteristics.

Procalcitonin and C-reactive protein levels in HIV-positive subjects with tuberculosis and pneumonia

Pulmonary tuberculosis (PTB) and pneumococcal community-acquired pneumonia (PCAP) are common causes of lower respiratory tract infections in HIV-seropositive patients and may have similar clinical and radiological features. This study aimed to assess the value of serum procalcitonin (PCT) and C-reactive protein (CRP) levels in HIV-seropositive patients with pneumonia, and to investigate their potential role in differentiating pneumococcal from mycobacterial infections. HIV-seropositive patients admitted with pneumonia were evaluated prospectively, 34 with PTB and 33 with PCAP. All 33 patients in the PCAP group and 20 of 34 patients in the PTB group had elevated PCT levels (>0.1 ng x mL(-1)). All patients in both groups had elevated CRP levels (>10 mg x L(-1)). The PTB group had significantly lower CD4 T-lymphocyte counts, lower CRP levels, lower white cell counts, and lower PCT levels than the PCAP group. Receiver operating characteristic analysis showed that optimal discrimination between PTB and PCAP could be performed at a cut-off point of 3 ng x mL(-1) for PCT (sensitivity 81.8%; specificity 82.35%) and 246 mg x L(-1) for CRP (sensitivity 78.8%; specificity 82.3%). In conclusion, HIV-seropositive patients with pneumococcal community-acquired pneumonia had significantly higher procalcitonin and C-reactive protein levels than those with pulmonary tuberculosis. A procalcitonin level >3 ng x mL(-1) and a C-reactive protein level >246 mg x L(-1) were both highly predictive of pneumococcal infection.

Vascular leucocyte adhesion molecules unaltered in the human retina in diabetes

BACKGROUND/AIMS

Capillary occlusion is believed to have a critical role in the development of diabetic retinopathy (DR). The exact mechanism by which it occurs, however, remains unclear. Several in vitro and animal model studies have suggested increased adhesion of leucocytes to the endothelium via upregulated ICAM-1 on the retinal microvasculature as a possible mechanism. In this comparative immunohistochemical study the expression of ICAM-1 was compared in the retinal vasculature of 41 eyes obtained from 37 diabetic people with 19 eyes from 19 non-diabetic controls.

METHODS

Serial cryosections of postmortem posterior tissue from 41 diabetic eyes and 19 non-diabetic eyes were stained with the monoclonal antibodies ICAM-1 (two clones), CD31(panendothelial marker), and PAL-E (vascular leakage marker).

RESULTS

A similar pattern of vascular ICAM-1 staining was observed between diabetic and non-diabetic eyes. A diffuse ICAM-1 staining of the retina was also observed that was significantly more intense in the diabetic subjects (p = 0.001).

CONCLUSION

These results indicate that ICAM-1 is constitutively expressed on retinal and choroidal vasculature of non-diabetic, control subjects and that this level of expression is not significantly altered by the diabetic environment. Taken together, these results do not support the prevalent paradigm of increased adhesion molecule expression as a primary mechanism responsible for capillary occlusion reported in diabetic individuals.

Operational assessment of isoniazid prophylaxis in a community AIDS service organisation in Uganda

SETTING

Isoniazid therapy was shown to be 70% effective at preventing tuberculosis in HIV-infected, PPD-positive Ugandan adults, but the feasibility of implementation outside an efficacy trial has not been established.

OBJECTIVE

To study uptake, adherence and feasibility of a 6-month course of isoniazid preventive therapy in community-based HIV clinics in Uganda.

DESIGN

Observational cohort study describing selection of patients and adherence to isoniazid 300 mg daily. Adherence was measured by clinic attendance, pill counts and urine isoniazid metabolite testing. Implementation was costed on a service delivery basis.

RESULTS

Of 1597 cohort members, 22% were PPD-positive. Over 18 months, 193 PPD-positive individuals were assessed for prophylaxis and 98 (51%) were enrolled. Of those enrolled, 74 (76%) completed their course of isoniazid therapy, and 80% were fully adherent. Symptoms or previous treatment for tuberculosis and suspicion of tuberculous lymphadenopathy were the main reasons for exclusion. The additional cost of providing this service was US $14,549.

CONCLUSION

Clinics specialising in the care of persons with HIV/AIDS can successfully implement isoniazid prophylaxis. Difficulties in excluding active tuberculosis and the costs of running the programme may limit its widespread implementation.

Use of up-converting phosphor reporters in lateral-flow assays to detect specific nucleic acid sequences: a rapid, sensitive DNA test to identify human papillomavirus type 16 infection

BACKGROUND

A lateral-flow (LF) device using the new reporter up-converting phosphor technology (UPT) was applied to DNA (hybridization) assays for the detection of specific nucleic acid sequences, thereby aiming to perform the test outside well-equipped laboratories. The methodology reported here is sensitive and provides a rapid alternative for more elaborate gel electrophoresis and Southern blotting. In a preliminary study, it was applied to screen for the presence of human papillomavirus type 16 (HPV16) in a defined series of cervical carcinomas.

METHODS

A LF assay was used to capture haptenized DNA molecules and hybrids, which were immunolabeled (before LF) with 400-nm UPT particles. These particles emit visible light after excitation with infrared in a process called up-conversion. Because up-conversion occurs in only the phosphor lattice, autofluorescence of other assay components is virtually nonexistent.

RESULTS

The use of the UPT reporter in LF-DNA tests, as compared with colloidal gold, improved the detection limit at least 100-fold. UPT LF-DNA tests were successfully applied to detect (in a blind test) the presence of HPV16 in DNA extracts obtained from cervical carcinomas. Test results matched 100% with previous characterization of these carcinomas.

CONCLUSIONS

The use of UPT in LF assays to detect specific nucleic acids provides low attamole-range sensitivity. Hybridization and consecutive detection of PCR-amplified HPV16 sequences were successful in a background of 10 microg of fish-sperm DNA. The sensitivity of UPT detection in these complex mixtures indicates that detection of viral infections without PCR or other amplification technique is achievable.

Comparative analysis of the expression of the Epstein-Barr virus (EBV) anti-apoptotic gene BHRF1 in nasopharyngeal carcinoma and EBV-related lymphoid diseases

Epstein-Barr virus (EBV) has been identified in a wide range of neoplastic and non-neoplastic disorders. The EBV open reading frame BHRF1 encodes a protein with partial sequence and functional homology to the anti-apoptotic onco-protein Bcl-2 and may therefore have a role in the proliferation of EBV positive cells. We have developed a rat monoclonal antibody against pBHRF1, which can detect BHRF1 in paraffin sections. While a number of mutant versions of BHRF1 were recognised, the monoclonal did not detect the BHRF1 homologue encoded by Herpesvirus papio or two mutants with deletions in the BH2 region. This novel rat monoclonal antibody (6A9) was used to examine tissue sections from 39 cases of non-keratinising undifferentiated nasopharyngeal carcinoma (NPC), 6 cases of metastatic NPC, 7 cases of EBV-positive NPC with squamous differentiation from Chinese patients, 15 cases of EBV-positive post-transplant lymphoproliferative disorder (PTLD), 6 EBV-containing lymphoblastoid cell lines, and 2 cases of oral hairy leukoplakia (OHL). In 11 cases of undifferentiated NPC, RT-PCR data were available for comparison with the immunohistochemistry. Both cases of OHL and two cases of LCL were positive for BHRF1 but none of the PTLD showed positive staining. All cases of undifferentiated NPC were positive for Bcl-2 but only one BHRF1 positive cell was identified in 1 of 39 cases of primary undifferentiated NPC. The 6A9 antibody produced less background staining and no nuclear positivity compared with the commercially available mouse monoclonal 5B11. It is concluded that BHRF1 can not be detected by immunohistochemistry in NPC and therefore it appears not to play a significant anti-apoptotic role in the progression of this EBV-associated tumour. The 6A9 monoclonal appears to be superior to 5B11 for the detection of pBHRF1 in tissue sections.

Serotype 19f multiresistant pneumococcal clone harboring two erythromycin resistance determinants (erm(B) and mef(A)) in South Africa

One hundred eighteen erythromycin-resistant Streptococcus pneumoniae (ERSP) strains (MICs of > or = 0.5 microg/ml) from five laboratories serving the private sector in South Africa were analyzed for the genes encoding resistance to macrolides. Sixty-seven ERSP strains (56.8%) contained the erm(B) gene, and 15 isolates (12.7%) contained the mef(A) gene. Thirty-six isolates (30.5%) harbored both the erm(B) and mef(A) genes and were highly resistant to erythromycin and clindamycin. DNA fingerprinting by BOX-PCR and pulsed-field gel electrophoresis identified 83% of these strains as belonging to a single multiresistant serotype 19F clone.

Functional CD4(+) and CD8(+) T-cell responses induced by autologous mitomycin C treated Epstein-Barr virus transformed lymphoblastoid cell lines

Epstein-Barr virus (EBV) gene expression in tumor cells of posttransplant lymphoproliferative disorder (PTLD) patients resembles that of EBV transformed B-cell lines (LCL). EBV-specific cytotoxic T-lymphocytes can be generated by stimulating peripheral blood lymphocytes with autologous LCL. We describe a standardized method for the growth inactivation and cryopreservation of LCL for optimal T-cell stimulation and analyzed the function and phenotype of responding T-cells. LCL growth was completely blocked by mitomycin C treatment (McLCL) and McLCL could be cryopreserved while retaining excellent APC function. McLCL stimulated both CD4(+) and CD8(+) T-cells as measured by HLA-DR and CD25 expression using FACS analysis. EBV-specific CTL activity and T-cell proliferation were induced and immunocytochemical staining showed CD4(+) and (granzyme B positive) CD8(+) T-cells rosetting with McLCL. Granzymes A and B, IFN-gamma, and IL-6 were detected at significant levels in the supernatant. Thus, ex vivo T-cell activation with cryopreserved McLCL results in activation of both CD4(+) and CD8(+) T-cells producing a Th1-like cytokine profile, making this a suitable protocol for adoptive therapy of PTLD.

Epidemiology of glycopeptide-resistant enterococci colonizing high-risk patients in hospitals in Johannesburg, Republic of South Africa

Recent cases of infections caused by glycopeptide-resistant enterococci (GRE) have highlighted the emergence of these organisms in the Republic of South Africa. During May 1998 we conducted a prevalence study in four hospitals in Johannesburg and obtained 184 rectal swabs from patients identified as being at high risk for GRE colonization. Twenty enterococcal isolates showing various glycopeptide resistance genotypes were recovered: 3 Enterococcus faecium vanA isolates, 10 E. faecium vanB isolates, 6 E. gallinarum vanC1 isolates, and 1 E. avium vanA isolate. Macrorestriction analysis was used to demonstrate the clonal spread of GRE strains within hospitals. Evidence also demonstrated the likely persistence of the original E. faecium vanA isolate associated with the first confirmed death contributed to by GRE infection in South Africa in March 1997.

LFA-1 to LFA-1 signals involve zeta-associated protein-70 (ZAP-70) tyrosine kinase: relevance for invasion and migration of a T cell hybridoma

We previously showed that LFA-1-dependent in vitro invasion and in vivo migration of a T cell hybridoma was blocked in cells overexpressing a truncated dominant-negative zeta-associated protein (ZAP)-70. The truncated ZAP-70 also blocked LFA-1-dependent chemotaxis through ICAM-1-coated filters induced by 1 ng/ml stromal cell-derived factor-1, but not LFA-1-independent chemotaxis induced by 100 ng/ml stromal cell-derived factor-1. This suggested that LFA-1 engagement triggers a signal that amplifies a weak chemokine signal and that dominant-negative ZAP-70 blocks this LFA-1 signal. Here we show that cross-linking of part of the LFA-1 molecules with Abs causes activation of free LFA-1 molecules (not occupied by the Ab) on the same cell, which then bind to ICAM-2 on other cells. This causes cell aggregation that was also blocked by dominant-negative ZAP-70. Thus, an LFA-1 signal involving ZAP-70 activates other LFA-1 molecules, suggesting that the chemokine signal can be amplified by multiple cycles of LFA-1 activation. The chemokine and the LFA-1 signal were both blocked by a phospholipase C inhibitor and a calpain inhibitor, suggesting that one of the amplified signals is the phospholipase C-dependent activation of calpain. Finally, we show that both Src-homology 2 domains are required for inhibition of invasion, chemotaxis, and aggregation by the truncated ZAP-70, suggesting that ZAP-70 interacts with a phosphorylated immunoreceptor tyrosine-based activation motif (ITAM) sequence. Remarkably, this is not an ITAM in the TCR/CD3 complex because this is not expressed by this T cell hybridoma.

Restricted low-level human antibody responses against Epstein-Barr virus (EBV)-encoded latent membrane protein 1 in a subgroup of patients with EBV-associated diseases

Human antibody responses to latent membrane protein 1 (LMP1) in patients with Epstein-Barr virus (EBV)-related disease syndromes were analyzed in detail. Only by immunoblot analysis with purified recombinant LMP1 and by IFA on recombinant LMP1-expressing insect cells could human antibodies directed against LMP1 be detected. Low serum levels of LMP1-directed antibodies could be detected in 3 of 8 EBV-positive Hodgkin's disease patients, 3 of 40 nasopharyngeal carcinoma patients, 2 of 23 Burkitt's lymphoma patients, and 1 of 27 non-Burkitt's lymphoma patients. No LMP1-directed antibodies could be detected in healthy EBV carriers, infectious mononucleosis patients, or patients with chronic EBV disease. All sera contained significant levels of EBV antibodies directed against the immunodominant EBV proteins and peptides. From this study, it can be concluded that LMP1 is a protein with a very low immunogenicity for the humoral immune response in humans.

mu-Conotoxin PIIIA, a new peptide for discriminating among tetrodotoxin-sensitive Na channel subtypes

We report the characterization of a new sodium channel blocker, mu-conotoxin PIIIA(mu-PIIIA). The peptide has been synthesized chemically and its disulfide bridging pattern determined. The structure of the new peptide is: [sequence: see text] where Z = pyroglutamate and O = 4-trans-hydroxyproline. We demonstrate that Arginine-14 (Arg14) is a key residue; substitution by alanine significantly decreases affinity and results in a toxin unable to block channel conductance completely. Thus, like all toxins that block at Site I, mu-PIIIA has a critical guanidinium group. This peptide is of exceptional interest because, unlike the previously characterized mu-conotoxin GIIIA (mu-GIIIA), it irreversibly blocks amphibian muscle Na channels, providing a useful tool for synaptic electrophysiology. Furthermore, the discovery of mu-PIIIA permits the resolution of tetrodotoxin-sensitive sodium channels into three categories: (1) sensitive to mu-PIIIA and mu-conotoxin GIIIA, (2) sensitive to mu-PIIIA but not to mu-GIIIA, and (3) resistant to mu-PIIIA and mu-GIIIA (examples in each category are skeletal muscle, rat brain Type II, and many mammalian CNS subtypes, respectively). Thus, mu-conotoxin PIIIA provides a key for further discriminating pharmacologically among different sodium channel subtypes.

Diagnostic disagreement--the lessons learnt from malaria diagnosis in Mpumalanga

Diagnostic tests that require human interpretation will always be susceptible to error. This may lead to delays in initiating effective therapy for potentially fatal conditions. The Malaria Control Programme in South Africa has historically relied on the microscopic examination of Giemsa-stained thick blood smears to confirm the clinical diagnosis of malaria. The level of agreement of malaria laboratory diagnosis performed by the four laboratories serving the Mpumalanga Province Malaria Control Programme was investigated. The disagreement between the laboratories argues in favour of a uniform training and quality assurance programme or the introduction of alternative diagnostic modalities. It should also serve as a caution against diagnostic complacency in other public health programmes.

Expression of Epstein-Barr virus encoded latent genes in nasal T cell lymphomas

AIMS

To determine the expression of Epstein-Barr (EB) virus encoded latent genes in nasal T-cell lymphomas in The Netherlands.

METHODS

Seven europid (Dutch) cases of nasal T cell lymphoma were investigated for the presence of EB virus by RNA in situ hybridisation (EBER). The expression of the EB virus encoded genes BARF0, EBNA1, EBNA2, LMP1, LMP2A, LMP2B, and ZEBRA was studied at the mRNA level using reverse transcriptase polymerase chain reaction. At the protein level the expression was investigated of EBNA2 and LMP1 by immunohistochemistry.

RESULTS

In all seven nasal T cell lymphomas EBER was detected in the nuclei of virtually all tumour cells. BARF0 mRNA was detected in all samples. EBNA1 mRNA was found in six cases, LMP1 mRNA in five, LMP2A mRNA in three, LMP2B mRNA in one, and ZEBRA mRNA in one. EBNA2 mRNA was not found in any case. At the protein level occasional LMP1 positive tumour cells were seen in only one case. The EBNA2 protein was not detected.

CONCLUSIONS

Nasal T cell lymphomas in The Netherlands are strongly associated with EB virus. The virus shows a type II latency pattern (EBNA1+, LMP1+, EBNA2-) that seems to be similar to the EB virus associated nasal T cell lymphomas in oriental countries.

Purinoceptor-mediated modulation by endogenous and exogenous agonists of stimulation-evoked [3H]noradrenaline release on rat iris

To investigate whether endogenous purinoceptor agonists affect the sympathetic neurotransmission in the rat isolated iris, and to classify the purinoceptors modulating exocytotic [3H]-noradrenaline release, we have determined the effect of adenosine receptor antagonists on, and the relative potency of selected agonists in modulating, the field stimulation-evoked (3 Hz, 2 min) [3H]-noradrenaline overflow. In addition, the apparent affinity constants of 8-phenyltheophylline (8-PT) and 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) in antagonizing the prejunctional effects of purinoceptor agonists were estimated. The relatively A1-selective DPCPX 10 and 100 nmol/l increased the evoked [3H]-noradrenaline overflow by about 25%-35% indicating a minor inhibition of evoked release by endogenous purinoceptor agonists probably via an A1 adenosine receptor. Whereas the A1/A2-antagonist 8-PT failed to increase the evoked [3H]-noradrenaline overflow in the absence of exogenous agonists (without or with dipyridamole 1 mumol/l present), the relatively A2-selective antagonist CP-66,713 (4-amino-8-chloro-1-phenyl(1,2,4)triazolo(4,3-a)quinoxaline) 100 nmol/l decreased it by 20%-30% in the absence and continuous presence of DPCPX. This may be compatible with a minor A2-mediated facilitation by an endogenous purinoceptor agonist. All exogenous agonists tested (except UTP 100 mumol/1) inhibited the evoked [3H]-noradrenaline overflow. The relative order of agonist potency (IC40, concentration in mumol/l for inhibition of evoked release by 40%) was CPA (N6-(cyclopentyl)adenosine, 0.004) greater than R-PIA (R(-)N6-(2-phenylisopropyl)adenosine, 0.066) = CHA (N6-(cyclohexyl)adenosine, 0.082) greater than NECA (N5-(ethyl-carboxamido)adenosine 0.44) greater than ADO (adenosine, 4.1). ATP was nearly equipotent with ADO. Maximum inhibition was 70%-80% and similar for all agonists.(ABSTRACT TRUNCATED AT 250 WORDS)

Unusual cranial and abdominal computed tomographic (CT) scan appearances in a case of systemic lupus erythematosus (SLE)

A 35 year old woman presented with headache and fever. Computed brain tomography showed diffuse low attenuation in the cerebral white matter. Several months later, serological tests for systemic lupus erythematosus (SLE) became positive. In spite of immunosuppressive therapy she relapsed after six months of treatment, presenting with abdominal symptoms and signs. On this occasion an abdominal CT scan showed distended and oedematous loops of bowel attributed to an underlying vasculitis. This case illustrates novel CT scan appearances in two systems involved in SLE.

Depression and loss: a theme in Robert Burton's "Anatomy of melancholy" (1621)

Robert Burton's Anatomy of Melancholy (1621) can hardly be thought of as a modern study in psychiatry, but it contains more elements of modern theory than have been recognized. Attempts to recommend the book to modern readers have missed the point that Burton, more clearly than other seventeenth century writers on melancholy, sees traumatic loss of attachment figures, status symbols and personal health as predisposing to mood disorders. In this he strongly anticipates such work as that of John Bowlby in Attachment and Loss (1969), 1973). Burton's theory is divided between the humoural physiological theory descending from Galen and the observation that loss is a frequent precursor of melancholy. He cannot reconcile the two, writing a book only poised on the verge of modernity. The Anatomy of Melancholy nevertheless very fully discusses etiological "hunches" which have found verification in recent studies of traumatic loss.

Protein synthesis in the myocardiopathy and muscular dystrophy of the Syrian hamster

1. Incorporation in vitro of l-[4,5-3H]leucine and l-[U-14C]lysine into a soluble protein fraction and into actomyosin of hearts, diaphragms and biceps femoris of an inbred strain of Syrian hamsters suffering from a hereditary myocardiopathy and muscular dystrophy was studied.

2. Incorporation of both amino acids was normal in myopathic hearts from hamsters aged 60–90 days but significantly elevated at 180–240 days of age. Their incorporation was higher in the myopathic diaphragm and biceps femoris of both age groups.