Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity.

We administered either 1 or 3 g/d of pyridoxine (vitamin B6) to five healthy volunteers and repeatedly followed serum pyridoxal phosphate levels, clinical symptoms and signs, quantitative sensory thresholds (QSTs), and sural nerve electrophysiology. Pyridoxine was discontinued at the first sign of either clinical or laboratory abnormality. In all subjects, sensory symptoms and QST abnormalities occurred concurrently. Subjects receiving higher doses became symptomatic earlier than low-dose subjects. Elevation of thermal QSTs preceded or exceeded that for vibration in the three low-dose subjects; vibration and thermal QST became abnormal simultaneously in the higher-dose subjects. A reduction in the amplitude of the sural sensory potential lagged behind QST changes in two of three subjects. Symptoms continued to progress ("coasting") for 2 to 3 weeks despite stopping pyridoxine administration and the return of serum pyridoxal phosphate levels to normal. This study suggests that (1) there is a clear dose-percent relationship for pyridoxine-induced neuropathy, (2) QST is a sensitive measurement for detecting early peripheral neuropathy; QST abnormalities may precede changes in nerve conduction studies, (3) coasting appears unrelated to persistently elevated blood levels of the toxin, and (4) a dose-dependent vulnerability may exist among nerve fibers of different caliber when exposed to an axonal toxin, such as pyridoxine.     

Surgical indications status in ileus using a simple clinical index

Based on a retrospective analysis of a group of patients with ileus disease in regard of the indication for operative intervention an "ileus index" was created which is derived from simple clinical and radiological findings and laboratory data. Prospective evaluation of this index showed its effectiveness in separating patients who had to undergo an emergency operation from those who could be operated electively after preceding diagnostic procedures or could be treated conservatively.     

Prevalence and phylogenetic characterisation of TT-virus in the blood donor population of Auckland, New Zealand

TT-virus (TTV, patient initials: T.T.), a novel DNA virus, was first isolated in Japan in 1997 from serum of a patient with post-transfusion hepatitis of unknown aetiology. To date, the contribution of TTV to liver disease remains doubtful. The potential for transmission via blood and blood products makes it essential to establish the prevalence of TTV viraemia in the blood donor population. 413 blood donor serum samples were chosen randomly, the DNA was extracted and TTV-specific DNA amplified by nested polymerase chain reaction (PCR). TTV infection was present in 13 out of 413 (3.15%) blood donors in the Auckland region of New Zealand using a set of primers targeting open reading frame (ORF) 1. These 13 amplification products (264 bp) were sequenced and TTV genotypes determined. Alignment with published TTV sequences showed that seven (53.8%) of the thirteen positive serum samples belonged to genotype 1, five (38.5%) belonged to genotype 2 and one (7.7%) could not be classified as either genotype 1 or 2. One hundred twenty-seven blood donor serum samples were retested with a second set of primers targeting the 5' region of the TTV genome in a single round PCR. Forty-three samples were positive for TTV DNA with these primers resulting in a prevalence of 37%. The data demonstrate that TTV is present among New Zealand blood donors and support the need for further investigation into the natural history of TTV infection.     

Case of synovitis potentially caused by Dolosigranulum pigrum

We report a case of synovitis in a 64-year-old man who developed the infection while on steroid therapy for rheumatoid arthritis. Dolosigranulum pigrum, a gram-positive catalase-negative coccus, was isolated from two sets of blood cultures prior to antibiotic therapy. The patient was treated with 4 weeks of appropriate antibiotics, and the synovial inflammation resolved. Although synovial aspirates were never positive for any bacteria or fungi, the timing of positive blood cultures and absence of other pathogens suggest the possible etiology as D. pigrum.     

Pokeweed mitogen and Staphylococcus aureus Cowan I induced immunoglobulin A synthesis by lymphocytes of IgA deficient blood donors.

In vitro IgA synthesis induced by pokeweed mitogen (PWM), Staphylococcus aureus Cowan I (STA), and combinations of STA and PWM (STA/PWM) was studied in lymphocytes of IgA deficient (sIgAd) blood donors. Cultures of T-depleted (non-T) cells with autologous or allogeneic control T, irradiated T (T), or T4 cells suggested abnormalities in non-T cell fractions in most (12/22) sIgAd donors. T cell abnormalities in themselves, detectable in six donors, did not appear to account for the failure of IgA synthesis. Repeat studies in 10 donors indicated fluctuations in in vitro IgA synthesis in four. IgA synthesis induced by STA/PWM combinations was observed in only one of eight sIgAd donors. Our findings suggest that in some donors defects leading to failure to produce IgA may not be constant and support the hypothesis of a maturation arrest in IgA+ B cells in sIgAd donors.     

Genetic linkage maps of the West African clawed frog Xenopus tropicalis.

Amphibians, and particularly the African clawed frog Xenopus laevis, have been used for more than a century as models of vertebrate embryonic development. However, in many cases, elucidation of developmental functions of specific gene sequences could be severely impeded, because X. laevis is a tetraploid species, with multiple functional copies of many genes of interest. Recent studies have shifted focus to the West African or tropical clawed frog, X. tropicalis, the only known diploid species of the genus Xenopus. Here, we present two preliminary linkage maps, constructed by analysis of joint segregation of amplified fragment length polymorphism (AFLP) markers in a X. tropicalis interstrain hybrid. A total of 53 markers, including 51 AFLP markers and 2 isozyme markers, are presently assigned to 13 multipoint linkage groups on a map of the maternal strain, whereas 9 AFLP markers from the paternal strain are assigned to 3 linkage groups on a separate map. A dense genetic linkage map is essential in mapping new developmental mutants and determining their sequences by positional cloning.     

Human polymorphonuclear leukocyte interaction with cyclosporine A.

The effects of cyclosporin A (cyA) on human polymorphonuclear leukocyte function, including phagocytosis, its associated metabolic burst, bacterial killing, and chemotaxis, were evaluated. Both Pseudomonas aeruginosa and Staphylococcus aureus were used as test particles. Polymorphonuclear leukocytes incubated in 10 and 50 micrograms of cyA per ml behaved normally with respect to phagocytosis and hexose monophosphate shunt activity at both high (10:1) and low (2:1) S. aureus/leukocyte ratios. With a small bacterial inoculum, killing of S. aureus was slightly impaired at early times only in the presence of 50 micrograms of cyA per ml. Phagocytosis and killing of P. aeruginosa with both large and small bacterial inocula were unaffected by cyA. Chemotaxis was within normal limits under all conditions. In addition, polymorphonuclear leukocytes from four renal transplant recipients receiving both cyA and prednisone demonstrated normal metabolic bursts and bacterial killing with both small and large inocula of S. aureus.