Model multiple antigenic and homopolymeric peptides from non-repetitive sequences of malaria merozoite proteins elicit biologically irrelevant antibodies

We describe here a new type of mitochondrial mutation (dum24; for dark uniparental minus inheritance) of the unicellular photosynthetic alga Chlamydomonas reinhardtii. The mutant fails to grow under heterotrophic conditions and displays reduced growth under both photoautotrophic and mixotrophic conditions. In reciprocal crosses between mutant and wild-type cells, the meiotic progeny only inherit the phenotype of the mating-type minus parent, indicating that the dum24 mutation exclusively affects the mitochondrial genome. Digestion with various restriction enzymes followed by DNA gel blot hybridizations with specific probes demonstrated that dum24 cells contain four types of altered mitochondrial genomes: deleted monomers lacking cob, nd4, and the 3' end of the nd5 gene; deleted monomers deprived of cob, nd4, nd5, and the 5' end of the cox1 coding sequence; and two types of dimers produced by end-to-end fusions between monomers similarly or differently deleted. Due to these mitochondrial DNA alterations, complex I activity, the cytochrome pathway of respiration, and presumably, the three phosphorylation sites associated with these enzyme activities are lacking in the mutant. The low respiratory rate of the dum24 cells results from the activities of rotenone-resistant NADH dehydrogenase, complex II, and alternative oxidase, with none of these enzymes being coupled to ATP production. To our knowledge, this type of mitochondrial mutation has never been described for photosynthetic organisms or more generally for obligate aerobes.     

Comparison of digital rectal examination and biopsy results with the radical prostatectomy specimen

PURPOSE: Digital rectal examination is integral to staging prostate cancer. Ultrasound guided biopsy establishes the diagnosis, and it may provide useful information regarding disease grade and extent. Treatment decisions are largely based on information gained from digital rectal examination and biopsy but this information is only useful if it correlates with the radical prostatectomy specimen and prognosis. We correlated digital rectal examination and transrectal ultrasound guided biopsy results with a detailed analysis of the radical prostatectomy specimen. MATERIALS AND METHODS: The accuracy of an abnormal digital rectal examination for predicting the location and extent of cancer was assessed in 89 patients thought to have clinical stage T2 disease. We evaluated 155 patients with clinical stages T1c and T2 disease to correlate the location of positive biopsies with the tumor site in the prostate. Radical prostatectomy specimens were completely sectioned at 2 mm. intervals, and tumor extent and location were recorded. RESULTS: In 85 patients a unilateral lesion was suspicious on digital rectal examination, that is stage cT2. The final pathological review revealed cancer on the suspicious side in 82 cases (96%) with tumor confined to the same lobe in only 23 (27%), bilateral disease in 59 (69%) and tumor confined to the contralateral lobe in 3 (4%). In 4 patients with a palpable bilateral abnormality a bilateral lesion was confirmed on final pathological evaluation. Digital rectal examination demonstrated a 36 and 31% incidence of extracapsular tumor extension and positive surgical margins, respectively, on the clinically benign side. In 100 patients only unilateral biopsy was positive. The final pathological evaluation revealed cancer in the biopsy positive side in 95 cases (95%) with tumor confined to the ipsilateral lobe in only 26 (26%), bilateral disease in 69 (69%) and tumor confined to the contralateral lobe in 5 (5%). In 46 of the 55 patients (84%) with bilateral positive biopsies tumor involved both sides but the pathologist did not identify cancer in both lobes in 9 (16%). While 100 patients had a unilateral negative biopsy, analysis of the prostatectomy specimen revealed carcinoma in the benign lobe in 74 (74%). Moreover, extracapsular tumor extension and a positive surgical margin were observed on the biopsy negative side in 31% of the patients. The degree to which digital rectal examination and biopsy results confirmed the final pathological evaluation was assessed using the kappa statistic, which revealed only slight agreement with each factor. The correlation of digital rectal examination and biopsy results with the location of extracapsular extension and positive margins was evaluated by the Spearman coefficient of correlation, which indicated poor agreement. When patients with unilateral versus bilateral positive biopsy were compared with respect to prognostic parameters, the difference was statistically significant for initial serum prostate specific antigen, the percentage of surface involved by tumor, biopsy and final Gleason scores, and the incidence of extracapsular extension of tumor. CONCLUSIONS: Digital rectal examination and the interpretation of prostate biopsy are not accurate clinical tools for defining the location and extent of prostatic carcinoma. Bilateral positive biopsy may be useful as an adjunct to the current clinical staging system.     

The changing presentation of pyloric stenosis

A triplet pregnancy in a 23-year-old woman was terminated at 15 weeks of gestation because of her severe hypertension, lung edema, and secondary hyperthyroidism. The pregnancy consisted of a hydatidiform mole with a 46,XY karyotype and two fetuses each with 46,XX and a 46,XY karyotype. To determine the zygosity and genetic origin of the mole and fetuses, PCR- and computer-assisted genotyping were performed at 27 CA-repeat marker loci that were distributed evenly over the genome. As a result, genotypes of the three pregnancy products were distinct from each other, indicating that the triplets were trizygotic. The mole lacked any maternal alleles but inherited both of the paternal alleles and/or one paternal allele in duplicate. This, along with the XY sex chromosome constitution, indicated that the mole resulted from dispermic androgenesis. The mother developed a persistent trophoblastic tumor thereafter.     

Application of dried blood spot specimens for serologic subtyping of human immunodeficiency virus type 1 in Thailand

Dried blood spot (DBS) specimens were assessed as an alternative to plasma for human immunodeficiency virus type 1 (HIV-1) serotyping by V3 loop peptide enzyme immunoassay. Nested PCR capable of distinguishing HIV-1 subtypes B and E was used as the reference standard. Ninety-two percent of DBS samples were typeable as either HIV-1 subtype B or E. Serotype results with DBS and plasma were identical for 254 of 257 specimens. A simple DBS collection method provides a convenient alternative for conducting HIV-1 serotype surveillance while retaining sensitivity and specificity.     

Magnetic Properties of Nickel–Zinc Ferrite Toroids Prepared from Nanoparticles

Toroids comprised of silica-coated 10 nm diameter nickel–zinc (Ni–Fe) ferrite nanoparticles (Ni_0.5Zn_0.5Fe₂O₄) have been fabricated by careful control of both the coating process and subsequent densification by viscous sintering. A narrow processing window is identified between a maximum temperature at which the nanoparticles coarsen, losing their super-paramagnetic properties, and a lower temperature required for viscous flow densification. Key to the successful fabrication was drying and cold isostatic pressing of the silica-coated nanoparticles; other routes invariably led to cracking during either drying or sintering. The super-paramagnetic blocking temperature, the coercive field, and remanent magnetization could all be controlled over a wide range by varying the thickness of the silica coating from 1 to 15 nm. The dipole–dipole coupling distance is estimated to be 4 nm. The high-frequency (1–500 MHz) properties were sensitive to the sintering temperature as well as the thickness of the silica coating. Toroids sintered at 1000°C or less exhibited no high-frequency magnetic losses and their permeability decreased with increasing temperature, suggesting that the permeability was controlled by thermally activated magnetization relaxation.     

Feasibility of a one–step process for desizing,scouring, bleaching and mercerisating cotton fabrics

In this study the desizing, scouring, bleaching and slack mercerising of cotton fabric by a one–step process at different sodium hydroxide concentrations, impregnation temperatures and curing times were examined. The results indicate that when the fabrics are mercerised at lower temperature, the strength retention and colour strength are enhanced. When the sodium hydroxide concentration is increased, these properties also increase. When cotton fabrics are mercerised for 3 min at 40C and cured for 30 s at 120C, their physical properties are similar to those obtained using a conventional two–step approach.     

Cerebral blood flow study using SPECT in patients with memory disorders

INTRODUCTION: Global amnesia (AG) is a dysfunction of memory, in which there is a sudden incapacity to remember recent events and assimilate new information. The aetiology is currently under discussion. The main hypotheses under consideration are an ischemic mechanism and an epileptic mechanism. OBJECTIVE: To study the cerebral blood flow in patients with temporary global amnesia (AGT) or permanent global amnesia (AGP) using functional neuroimaging techniques. MATERIAL AND METHODS: Four patients were studied. Two had severe alterations of fixation memory which had been present for months. The other two had a sudden loss of recent memory, although space-person orientation and immediate memory remained normal. In all cases the cerebral blood flow (FSC), was assessed by single photon emission tomography (SPECT), using Tc-HMPAO as the radio tracer. RESULTS: We describe 4 patients, 2 men and 2 women aged between 42 and 64.2 with AGT and the others with AGP. On SPECT there was temporal hypoperfusion in all 4 patients. In 2 cases there was associated parietal hypoperfusion and in 1 case there was frontal hypoperfusion. CONCLUSIONS: These findings suggest that AGT and AGP are of vascular origin and that SPECT is a useful diagnostic technique in patients with AG.     

Seasonal variations of urinary stone colic in Arabia

The western region of Saudi Arabia is an area with a high prevalence of urolithiasis. This study was designed to find the effect of climatic changes on the occurrence of urinary stone colic as well as the effect of Ramadan fasting and pilgrimage festival. The emergency room (E.R.) records at King Abdulaziz University Hospital in Jeddah were studied for 3 consecutive years. Males diagnosed as urinary colic during this period were recorded on monthly basis with correction for 30 days a month. Data were recorded before, during and after the fasting month as well as before and after the pilgrimage festival. The results showed a steady increase in urinary stone colic in the hot season with a maximum rate in the months of June, July and August. The mean number of males with stone colic in these months was 45.33, 44.19 and 45.16 respectively. The lowest number was in March (28.06) with a rate of 4.11 per 1000 patients. A strong correlation was found between urinary stone colic and both temperature and atmospheric pressure with a P value of < 0.0001. No significant correlation was observed with relative humidity and similarly no significant change in relation to Ramadan fasting or the pilgrimage festival. These results suggest that there is a clear stone season in this area corresponding to the hot summer months. No significant increase in urinary stone colic was observed in relationship to the fasting month of Ramadan or the pilgrimage festival.