Social aspects of malaria in Heping, Hainan

This paper presents findings from a study conducted in Heping Town, Qiongzhong County, Hainan Province, China. The study, conducted in 1992, used qualitative as well as quantitative methods to gather social, cultural and behavioural data associated with the acquisition, transmission and prevention of malaria, and the diagnosis and treatment of disease. These methods included focus groups, key informant and other in-depth interviews, and observations, a household survey and tests of school children of knowledge of malaria. The study is among the first to our knowledge that has utilized this broad mix of methods for tropical disease research in China.

[The role of intestinal permeability in the pathogenesis of ankylosing spondylitis]

By use of low molecular weight polyethlene glycol (PEG400) as tracer, a revised Chedwick method with capillary gas chromatography was used to examine the intestinal permeability in 49 subjects including patients with ankylosing spondylitis (AS) and rheumatoid arthritis (RA) and healthy controls. Recovery percentage, maximal recovery percentage [Rmax(%)] and Rmax(w) were used to find the effect of bowel permeability in the pathogenesis and disease flare up of AS, as well as the role of HLA-B27 for the bowel permeability. The results showed that in AS group, the recovery of first component (242D) was higher and the Rmax(%) was lower than those in the controls. No statistical difference was found with other indexes. The results indicated that bowel permeability is not elevated in AS. The passage of enteral bacteria antigen into the host may not result from the process of nonspecific penetration. We postulate that there may somehow be a process of "active transportation" in the pathogenesis of AS. More studies of the process are necessary to clarify its importance in the early stage of AS.

[A real-time analysis of 133 normal lens images by a computer]

According to the theory that the light scattering of the lens is correlated with the lens density, we designed a computerized system for the real-time analysis of the lens image. By measurement of the gray scale value of the lens optical section, the lens density is measured objectively and numerically. With the help of the system, 133 normal lens images were investigated. From the analysis of various age groups, we found that the grey scale values of the anterior cortex, posterior cortex and nucleus increase with the increase of age (P < 0.01), the grey scale values of the anterior and posterior cortex are significantly higher than the value of the nucleus (P < 0.05), but there is no significant difference between the values of the anterior and posterior cortex (P > 0.05), and there is also no significant difference in the comparisons of the grey scale values of the respective corresponding lens areas between the male and female.

[Assessment of coronary flow reserve in patients with angina pectoris]

Coronary flow reserve was assessed by using a computer-assisted method in 26 normal controls and 45 patients with significant coronary artery stenosis ( > or = 50% luminal narrowing) and 16 patients with syndrome X. After intracoronary administration of papaverine, the diameter, cross sectional area, blood velocity, flow volume and reserve capacity of both left anterior descending (LAD) and right coronary arteries (RCA) were lower in patients with significant coronary stenosis than in controls. Despite similar changes in the diameter and cross sectional area, the velocity, flow volume and reserve capacity of these two vessels were also lower in patients with syndrome X than in controls. We conclude that coronary flow reserve is reduced in patients with coronary artery stenosis or syndrome X due to different levels of coronary artery abnormalities.

Expression and purification of recombinant polyomavirus VP2 protein and its interactions with polyomavirus proteins

Recombinant polyomavirus VP2 protein was expressed in Escherichia coli (RK1448), using the recombinant expression system pFPYV2. Recombinant VP2 was purified to near homogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, electroelution, and Extracti-Gel chromatography. Polyclonal serum to this protein which reacted specifically with recombinant VP2 as well as polyomavirus virion VP2 and VP3 on Western blots (immunoblots) was produced. Purified VP2 was used to establish an in vitro protein-protein interaction assay with polyomavirus structural proteins and purified recombinant VP1. Recombinant VP2 interacted with recombinant VP1, virion VP1, and the four virion histones. Recombinant VP1 coimmunoprecipitated with recombinant VP2 or truncated VP2 (delta C12VP2), which lacked the carboxy-terminal 12 amino acids. These experiments confirmed the interaction between VP1 and VP2 and revealed that the carboxyterminal 12 amino acids of VP2 and VP3 were not necessary for formation of this interaction. In vivo VP1-VP2 interaction study accomplished by cotransfection of COS-7 cells with VP2 and truncated VP1 (delta N11VP1) lacking the nuclear localization signal demonstrated that VP2 was capable of translocating delta N11VP1 into the nucleus. These studies suggest that complexes of VP1 and VP2 may be formed in the cytoplasm and cotransported to the nucleus for virion assembly to occur.

Pseudogene of dihydrolipoyl succinyltransferase (E2k) found by PCR amplification and direct sequencing of rodent-human cell hybrid DNAs

Previous studies have indicated that the cDNA for the E2k component of the human alpha-ketoglutarate dehydrogenase complex (KGDHC) hybridized not only to a major locus on chromosome 14q24.3 in a region associated with familial Alzheimer's disease and with Joseph-Machado disease, but also to another locus on chromosome 1p31. We now report that PCR of genomic DNA and direct sequencing indicated that the chromosome 1 locus is an intronless pseudogene. PCR of genomic DNA amplified E2k fragments from mouse-human cell hybrids containing human chromosome 1 DNA but not from hybrids containing human chromosome 14 DNA. The resulting amplicons were of comparable sizes to those when the cDNA was used as template. The direct sequencing of these amplicons confirmed the lack of introns and indicated a frame shift, which led to the presence of four termination codons early in the coding region. PCR followed by direct sequencing of the amplicons appears to be a convenient method for identifying intronless pseudogenes.

Purification of recombinant budgerigar fledgling disease virus VP1 capsid protein and its ability for in vitro capsid assembly

A recombinant system for the major capsid VP1 protein of budgerigar fledgling disease virus has been established. The VP1 gene was inserted into a truncated form of the pFlag-1 vector and expressed in Escherichia coli. The budgerigar fledgling disease virus VP1 protein was purified to near homogeneity by immunoaffinity chromatography. Fractions containing highly purified VP1 were pooled and found to constitute 3.3% of the original E. coli-expressed VP1 protein. Electron microscopy revealed that the VP1 protein was isolated as pentameric capsomeres. Electron microscopy also revealed that capsid-like particles were formed in vitro from purified VP1 capsomeres with the addition of Ca2+ ions and the removal of chelating and reducing agents.

Localization of the gene (OGDH) coding for the E1k component of the alpha-ketoglutarate dehydrogenase complex to chromosome 7p13-p11.2

alpha-Ketoglutarate dehydrogenase (E1k), also designated oxoglutarate dehydrogenase (OGDH; EC 1.2.4.2), is a component of the enzyme complex that catalyzes the conversion of alpha-ketogluterate to succinyl coenzyme A, a critical step in the Krebs tricarboxylic acid cycle. Deficiencies in the activity of this enzyme complex have been observed in brain and peripheral cells of patients with Alzheimer's disease. This finding led us to localize the genes for the polypeptides that compose the alpha-ketoglutarate dehydrogenase complex (KDGHC). The E1k locus was mapped to chromosome 7p13-p11.2 using a pair of human/rodent somatic cell hybrid panels. A second related sequence, possibly a pseudogene, was identified and mapped to chromosome 10.

Isolation, characterization, and mapping of gene encoding dihydrolipoyl succinyltransferase (E2k) of human alpha-ketoglutarate dehydrogenase complex

We have isolated and sequenced cDNAs representing the full-length (2987-bp) gene for dihydrolipoyl succinyltransferase (E2k component) of the human alpha-ketoglutarate dehydrogenase complex (KGDHC) from a human fetal brain cDNA library. The E2k cDNA was mapped to human chromosome 14 using a somatic cell hybrid panel, and more precisely to band 14q24.3 by in situ hybridization. This cDNA also cross-hybridized to an apparent E2k pseudogene on chromosome 1p31. Northern analysis revealed the E2k gene to be ubiquitously expressed in peripheral tissues and brain. Interestingly, chromosome 14q24.3 has recently been reported to contain gene defects for an early-onset form of familial Alzheimer's disease and for Machado-Joseph disease. Future studies will be necessary to determine whether the E2k gene plays a role in either of these two disorders.

Preimplantation embryo development enhanced by epidermal growth factor

PURPOSE

Enhanced embryo maturity and advanced stages of cleavage at the time of embryo transfer are associated with superior pregnancy rates in in vitro fertilization procedures. This study was performed to assess the potential usefulness of epidermal growth factor (EGF) to enhance the development of murine preimplantation embryos cultured in vitro. Two-cell stage mouse embryos were cultured for 72 hr with EGF at concentrations of 0.1 to 100 ng/ml. The percentage of embryos which developed to the expanded and hatching blastocyst stage at 72 hr was determined.

RESULTS

The percentage of fully expanded and hatching murine blastocysts at 72 hr was significantly higher following incubation with EGF at concentrations of 2 ng/ml (44 +/- 4.1%; P < 0.02), 20 ng/ml (41 +/- 3.2%; P = 0.04), 50 ng/ml (43 +/- 2.5%; P < 0.04), and 100 ng/ml (46 +/- 3.6%; P = 0.001) compared to controls. This effect of enhanced embryonic development by EGF was neutralized by coincubation with 1.0 micrograms/ml of anti-EGF antibody.

CONCLUSION

EGF at concentrations of 2 to 100 ng/ml significantly enhanced the percentage of expanded and hatching murine blastocysts at 72 hr.

Alternatively spliced fibronectin molecules in the wounded cornea: analysis by PCR

PURPOSE

To determine whether certain fibronectin isoforms participate in corneal epithelial wound healing, the authors used the polymerase chain reaction to detect different splicing patterns of the EIIIA segment of fibronectin mRNA in epithelial scrape-wounded cornea of rats.

METHODS

Specific fibronectin cDNA sequences synthesized from rat cornea with total RNA were amplified with various sets of synthetic oligonucleotide primers.

RESULTS

The authors detected both the EIIIA+ and EIIIA- fibronectin mRNA isoforms during corneal wound healing. The kinetics of corneal expression of both total fibronectin mRNA and the EIIIA- fibronectin mRNA isoform was polyphasic; an initial decrease was followed by an increase at 45 minutes, a second increase at 2 hours, and a third increase at 4 days after wounding. EIIIA+ fibronectin mRNA, not found in normal cornea, also was detected during healing.

CONCLUSIONS

The expression of total fibronectin mRNA and both the EIIIA+ and EIIIA- fibronectin mRNA is upregulated during corneal epithelial wound healing. The expression of EIIIA+ fibronectin mRNA during wound healing, a fibronectin isoform that was highly expressed in embryonic tissue, suggests that this fibronectin isoform is involved functionally in corneal wound healing.

Polymorphous ventricular tachycardia after intracoronary papaverine: a report of 3 cases

Three cases with polymorphous ventricular tachycardia following a standard dose of intracoronary papaverine during 102 measurements of coronary flow reserve are reported. This study suggests that all patients should be closely monitored while receiving intracoronary papaverine and that extreme caution should be employed when the drug is administered to patients with QT interval prolongation and poor coronary flow reserve.

Characterization of the DNA binding properties of polyomavirus capsid protein

The DNA binding properties of the polyomavirus structural proteins VP1, VP2, and VP3 were studied by Southwestern analysis. The major viral structural protein VP1 and host-contributed histone proteins of polyomavirus virions were shown to exhibit DNA binding activity, but the minor capsid proteins VP2 and VP3 failed to bind DNA. The N-terminal first five amino acids (Ala-1 to Lys-5) were identified as the VP1 DNA binding domain by genetic and biochemical approaches. Wild-type VP1 expressed in Escherichia coli (RK1448) exhibited DNA binding activity, but the N-terminal truncated VP1 mutants (lacking Ala-1 to Lys-5 and Ala-1 to Cys-11) failed to bind DNA. The synthetic peptide (Ala-1 to Cys-11) was also shown to have an affinity for DNA binding. Site-directed mutagenesis of the VP1 gene showed that the point mutations at Pro-2, Lys-3, and Arg-4 on the VP1 molecule did not affect DNA binding properties but that the point mutation at Lys-5 drastically reduced DNA binding affinity. The N-terminal (Ala-1 to Lys-5) region of VP1 was found to be essential and specific for DNA binding, while the DNA appears to be non-sequence specific. The DNA binding domain and the nuclear localization signal are located in the same N-terminal region.

Induction of donor-specific transplantation tolerance to skin and cardiac allografts using mixed chimerism in (A + B-->A) in rats

Mixed allogeneic chimerism (A + B-->A) was induced in rats by reconstitution of lethally irradiated LEW recipients with a mixture of T-cell depleted (TCD) syngeneic and TCD allogeneic ACI bone marrow. Thirty-seven percent of animals repopulated as stable mixed lymphopoietic chimeras, while the remainder had no detectable allogeneic chimerism. When evaluated for evidence of donor-specific transplantation tolerance, only those recipients with detectable allogeneic lymphoid chimerism exhibited acceptance of donor-specific skin and cardiac allografts. Despite transplantation over a major histocompatibility complex (MHC)- and minor-disparate barrier, animals accepted donor-specific ACI skin and primarily vascularized cardiac allografts permanently, while rejecting third party Brown Norway (BN) grafts. The tolerance induced was also donor-specific in vitro as evidenced by specific hyporeactivity to the allogeneic donor lymphoid elements, yet normal reactivity to MHC-disparate third party rat lymphoid cells. This model for mixed chimerism in the rat will be advantageous to investigate specific transplantation tolerance to primarily vascularized solid organ grafts that can be performed with relative ease in the rat, but not in the mouse, and may provide a method to study the potential existence of organ- or tissue-specific alloantigens in primarily vascularized solid organ allografts.

Expression of yeast hexokinase in pancreatic beta cells of transgenic mice reduces blood glucose, enhances insulin secretion, and decreases diabetes

It has been proposed that endogenous hexokinases of the pancreatic beta cell control the rate of glucose-stimulated insulin secretion and that genetic defects that reduce beta-cell hexokinase activity may lead to diabetes. To test these hypotheses, we have produced transgenic mice that have a 2-fold increase in hexokinase activity specific to the pancreatic beta cell. This increase was sufficient to significantly augment glucose-stimulated insulin secretion of isolated pancreatic islets, increase serum insulin levels in vivo, and lower the blood glucose levels of transgenic mice by 20-50% below control levels. Elevation of hexokinase activity also significantly reduced blood glucose levels of diabetic mice. These results confirm the role of beta-cell hexokinase activity in the regulation of insulin secretion and glucose homeostasis. They also provide strong support for the proposal that reductions in beta-cell hexokinase activity can produce diabetes.

Nitric oxide production in host-versus-graft and graft-versus-host reactions in the rat

The present study was designed to determine whether .N = O produced in vivo during the rejection of histoincompatible tissues might permit serum NO2-/NO3- levels to serve as markers of a rejection reaction. Rat syngeneic and allogeneic liver, heart, bone marrow/spleen cell, small bowel, skin, and sponge matrix grafts were performed and the stable end-products of .N = O, NO2-/NO3-, were serially assayed in the serum of the grafted animals. A significant rise of serum NO2-/NO3- levels in the allografted animals preceded the onset of clinical signs of rejection or graft-versus-host disease, with the exception of the skin and sponge matrix graft models, where elevated serum NO2-/NO3- levels were never observed. In all transplant models, normal serum NO2-/NO3- levels were observed at all times in animals that received syngeneic grafts. Furthermore, treatment of allograft recipients with the immunosuppressive agents FK 506 or cyclosporine A inhibited .N = O production. Determination of serum creatinine levels demonstrated that the elevated serum NO2-/NO3- levels were not caused by kidney dysfunction. Serum NO2-/NO3- levels might be useful early serum markers of the initiation of a rejection reaction or graft-versus-host disease when functional markers of graft dysfunction are not apparent.

Antihistamine effect of supplemental ascorbic acid and neutrophil chemotaxis

Renewed interest in the antihistamine action of ascorbic acid has emerged with the recently recognized immunosuppressive role of histamine. We examined the antihistamine effect of acute and chronic vitamin C (VC) administration and its effect on neutrophil chemotaxis in healthy men and women. In the chronic study, 10 subjects ingested a placebo during weeks 1, 2, 5 and 6, and 2 g/day of VC during weeks 3 and 4. Fasting blood samples were collected after the initial 2-week period (baseline) and at the end of weeks 4 and 6. Plasma ascorbate rose significantly following VC administration compared to baseline and withdrawal values. Neutrophil chemotaxis rose 19% (NS) during VC administration, and fell 30% after VC withdrawal, but these changes were not correlated to plasma ascorbate levels (r = 0.01). Chemotaxis was inversely correlated to blood histamine (r = -0.32, p = 0.045), and, compared to baseline and withdrawal values, histamine levels were depressed 38% following VC supplementation. Blood histamine and neutrophil chemotaxis did not change 4 hours following a single 2 g dose of ascorbic acid, although plasma ascorbate rose 150%. These data indicate that VC may indirectly enhance chemotaxis by detoxifying histamine in vivo.