The filaria Litomosoides galizai in mites; microfilarial distribution in the host and regulation of the transmission

The mites, Bdellonyssus bacoti, are engorged on rodents having 800 to 60,000 microfilarie/10 mm3 blood. Quantitation of L. galizai larval development shows that an additional blood meal improves development and that high microfilaremiae do not result in a proportional increase in the number of infective larvae. The first important stage of transmission regulation occurs during ingestion of microfilariae: the numbers of ingested microfilariae are lower than expected in cases of high microfilaremia. This phenomenon cannot be ascribed to the mite vector that engorges a constant blood meal whatever the level of microfilaremia. Contrarily, one finds that microfilarial density in the small peripheral blood vessels (blood drawn from incision of the dorsal skin) increases less than in large blood vessels (retro-orbital sinus). A similar observation was reported by Dickerson et al. (1989) working with Wuchereria bancrofti. We assume that in both cases, the high microfilaremiae cause the small blood vessles accessible to the vector to become saturated with parasites. Although regulation during engorging is not the sole factor to monitor the infection in B. bacoti (another one operates during larval development of L. galizai), demonstrating its existence seems to us fundamental: it points out the concept that sub-ingestion, as well as over-ingestion, shows the inequalities of microfilarial densities in the host which seem to be dependent on mechanical factors such as the diameter of blood vessles and the size of microfilariae.     

Atypical Ph negative chronic myeloid leukaemia presenting as sudden profound deafness.

A patient with atypical Ph negative chronic myeloid leukaemia presented with the sudden onset of profound deafness. He survived only eight months. Detailed histological investigation performed at necropsy showed loss of ganglion cells and afferent nerve fibres in the cochlea and vestibule associated with extensive fibrosis and new bone formation in the labyrinthine spaces. Both leucophoresis and high dose chemotherapy capable of rapid cytoreduction are recommended in patients with chronic myeloid leukaemia with profound hearing loss, as conventional chemotherapy is rarely followed by recovery.     

Tritiated-thymidine uptake in mixed leucocyte cultures: effect of specific activity and exposure time

The degree of in vitro transformation of lymphocytes to blast cells can be estimated by measuring the uptake of radioactive precursors into DNA. We have used ³H-thymidine uptake to quantitate blastogenesis in mixed leucocyte cultures. In experiments designed to standardize this procedure, the kinetics of thymidine uptake were studied by adding 4 μCi of ³H-thymidine of varying specific activities to 5-day mixed cultures. With high specific activity (0·194 μg total thymidine/culture), the rate of uptake was constant for only about 6 hr, then declined. There was no further cellular uptake between 8 and 24 hr, even though the total radioactivity of the supernatant medium did not diminish appreciably. This decreasing rate of uptake was at least partly the result of thymidine degradation to thymine and dihydrothymine by cellular enzymes. It is also possible that eventual radiation damage to blast cell nuclei may have retarded DNA synthesis when ³H-thymidine specific activity was high. With decreasing specific activity (up to 19·4 μg thymidine/culture), the rate of uptake became more nearly linear throughout 24 hr exposure to the isotope. The possible effects of thymidine degradation and radiation damage should be considered when measuring radioactive thymidine uptake in vitro, and short labelling times should be used whenever feasible.     

The immune-dependence of schistosomicidal chemotherapy: relative lack of efficacy of an antimonial in Schistosoma mansoni-infected mice deprived of their T-cells and the demonstration of drug-antiserum synergy.

When T-cell deprived CBA mice, infected with Schistosoma mansoni, were treated orally with potassium antimony tartrate, the reduction in size of their worm burdens was less than in similarly treated, immunologically-intact animals. The defect in deprived mice could be restored by the administration of serum obtained from S. mansoni-infected normal mice simultaneously with the drug, but by a different route. A serum component, probably immunoglobulin, obtained from rabbits which had been injected with an extract from S. mansoni adult worms was also found to act synergystically with the antimonial in the chemotherapeutic eradication of S. mansoni worms from immunologically intact mice.     

Routine and specialised techniques in the diagnosis of haematological neoplasms.

The relative importance of traditional techniques used in the diagnosis of haematological neoplasms has altered during the past decade. Cytology and histology retain their central role but the importance of cytochemistry has declined, except in the diagnosis of AML. Immunophenotyping is of major importance in the diagnosis of ALL, some categories of AML and the LPDs. Cytogenetic and molecular genetic analysis are important in the diagnosis of CML and are becoming increasingly important in the diagnosis of chronic LPDs and other haematological neoplasms. Diagnostic haematology laboratories which are not specialist leukaemia centres should have ready access to all of these techniques to ensure optimal patient management. However, not all techniques need to be performed in every laboratory.     

Hypochromic macrocytes: are they reticulocytes?

Automated full blood counters measuring the size and haemoglobin concentration of individual red cells by high and low angle light scatter can provide estimates of the percentage of cells which are abnormal in either or both of these variables. The hypothesis that an increase in the number of large cells with a reduced haemoglobin content ("hypochromic macrocytes") was indicative of a reticulocytosis was investigated. A correlation was shown between the percentage of hypochromic macrocytes and the reticulocyte count. This correlation was too weak to allow the actual reticulocyte percentage to be predicted from the percentage of hypochromic macrocytes. An increased percentage of hypochromic macrocytes, however, often indicates an increased reticulocyte count and thus serves to chart the haematologist to this possibility.     

The relationships among height,penile length,and foot size

To determine whether "folk myths" regarding the relationships of penile size to body height and foot size have any basis in fact, 63 normally virilized men were studied. Height and stretched penile length were measured; shoe size was recorded and converted to foot length. Penile length was found to be statistically related to both body height and foot length, but with weak correlation coefficients. Height and foot size would not serve as practical estimators of penis length.     

Assessing tremor severity.

A clinical rating scale which measured the severity of tremor in 20 patients (12 with essential tremor and 8 with "dystonic" tremor) was assessed at specific anatomical sites for both inter and intra-rater reliability using four raters. The scores obtained with the scale were compared with the results of upper limb accelerometry, an activity of daily living self-questionnaire and estimates of the tremor induced impairment in writing and drawing specimens. The results show that, for the purposes of routine assessment and therapeutic trials, a clinical rating scale can produce reliable results which are a more valid index of tremor induced disability than standard postural accelerometry.