An improved colorimetric PCR-based method for detection and differentiation of Entamoeba histolytica and Entamoeba dispar in feces.

The epidemiological implications of the recent separation of "Entamoeba histolytica" into two separate species, pathogenic E. histolytica sensu stricto and commensal E. dispar, will not become apparent without methods of distinguishing between them which are applicable to large numbers of specimens. We have modified a PCR-based method to produce such a technique which may be completed in 1 day while still identifying 10(-1) E. histolytica and 1 to 10 E. dispar trophozoites per g of feces when present separately and 10 E. histolytica and 100 E. dispar trophozoites per g in the presence of 10(6) trophozoites per g of the other species. Applied to fecal specimens from 18 patients from which E. histolytica or E. dispar had been grown and identified to the species level by hexokinase isoenzyme analysis, the method in every case yielded the correct result. Positive and negative results are easily distinguished by eye, and we are now applying this technique to a large-scale epidemiological study of amebiasis in the eastern Mediterranean region.

Sublingual allergen administration. I. Selective suppression of IgE production in rats by high allergen doses.

Sublingual administration of a protein allergen to immunologically naïve rats suppressed subsequent allergen-specific IgE responses. Susceptibility to this form of immunotherapy was genetically determined, with some inbred rat strains displaying immunological tolerance in the IgE antibody class alone, whilst others developed concomitant suppression of IgG. Parallel gastric intubation experiments established that the development of tolerance by sublingual allergen administration proceeded independently of events occurring in the gut resulting from swallowing the allergen. These results are consistent with clinical reports which suggest that the oral mucosa is a potentially useful site for therapeutic modulation of allergic reactivity, and indicate that appropriate animal models can be developed to probe this important question. However, further research is required to determine the relevance of these findings to current sublingual desensitization practices.

Suppression of IgE responses by antigen inhalation: failure of tolerance mechanism(s) in newborn rats.

The natural response of immunocompetent adult animals to antigen inhalation is the development of T-lymphocyte mediated tolerance, particularly in the IgE-antibody class (Holt & Sedgwick, 1987). It has been suggested that this process functions as a protective mechanism to limit sensitization to aeroallergens. In the present report, it is shown that the inhalation tolerance process does not function during the early postnatal period, and the lack of this protective mechanism may contribute to the increased risk of allergic sensitization during infancy. These experiments also demonstrate that adoptive transfer of adult splenocytes to newborns confers adult capacity for tolerance development, which suggests that delayed maturation of certain T-cell subset(s) may underly this transfer defect.

Suppression of IgE responses by passive antigen inhalation: dissociation of local (mucosal) and systemic immunity.

Animals from high- and low-IgE-responder rat strains were preexposed to antigen-containing aerosols of different droplet sizes, prior to parenteral antigenic challenge. Depending upon the type of aerosol employed, systemic immunological tolerance developed in high-IgE-responder animals in the IgE antibody class either with or without concomitant production of salivary IgA, indicating that the two antibody isotypes were under independent control, and further that IgA-mediated immune exclusion was not central to the development of tolerance in the IgE class. Low-IgE-responder rats exhibited biphasic salivary IgA responses during exposure, which could not be recalled by subsequent parenteral challenge, suggesting that secretory immunity in the respiratory tract may also be down regulated by repeated exposure to airborne antigens.

Suppression of IgE responses by antigen inhalation: studies on the role of genetic and environmental factors.

Repeated inhalation of low levels of ovalbumin (OVA) by mice or rats preferentially induces tolerance in the IgE antibody class, and this process may represent an important protective mechanism that normally prevents allergic sensitization to air-borne antigens. Dose-response experiments involving exposure of a number of inbred rat strains to graded doses of aerosolized OVA confirmed the inverse relationship between sensitivity to tolerogenesis and IgE-responder phenotype. These experiments additionally demonstrated that F1 hybrids derived from low X high responder crosses co-inherited high sensitivity to tolerance induction, together with the low IgE-responder phenotype. Sensitivity to tolerance induction in low versus high IgE-responder strains was found to be independent of the route of administration of OVA, indicating that the relevant genetically determined control mechanism(s) operated systemically. However, pre-exposure of animals to a variety of exogenous agents, noteably inhaled irritants (NO2 and histamine), the inflammatory adjuvants pertussigen and aluminium hydroxide injected at sites that stimulate the regional lymph nodes draining the respiratory tract, or a single subcutaneous injection of the reticuloendothelial system stimulator oestradiol, were shown to partially abrogate this natural tolerance process and promote allergic sensitization.

[Risks of operative treatment of prostatic adenoma in terminal renal failure]. / Gefahren der operativen Behandlung des Prostataadenoms im terminalen Nierenversagen.

Three patients in terminal renal failure who developed strictures in the operative area after the operative removal of a prostate adenoma are presented. These typical complications, as described in the literature, are not only a result of transurethral resections. According to our investigations they also develop after open prostate operations. Strictures are a result of an insufficient or lacking urinary flow in terminal renal failure. When sufficient quantity of fluid can be offered to the bladder for drainage through a suprapubic catheter strictures after transurethral and open prostate operations can be avoided.

A physiotherapist's views on low back pain.

It is a matter for regret that patients sometimes are sent by doctors for physiotherapy before their condition has been assessed fully. In this article a manipulative therapist describes his management, preceded always by thorough and careful examination. He emphasises that most physiotherapists work in close association with referring practitioners. The examination described would supplement that of the doctor and the findings would be discussed with him.

Isolation of Murray Valley encephalitis virus and other arboviruses in the Ord River Valley 1972-1976.

This paper summarizes the isolation of arboviruses from mosquitoes collected in the Ord Valley between 1972 and 1976. A total of one hundred and ninety five strains of at least fifteen antigenically distinct viruses have been isolated. Seven of these isolates appear to be "new' antigenic types, and several are undergoing further testing. These are three new rhabdoviruses (Kununurra [OR194], a virus provisionally named Kimberley [OR250] and OR189 [provisionally named Parry's Creek]), three ungrouped, non-haemagglutinating viruses (OR379, OR512, OR869) and a virus (OR540) which reacts to Poly Anopheles A world grouping fluid. The remaining viruses have been previously identified in Australia. These include Murray Valley encephalitis (MVE), Kunjin, Kokobera, Sindbis, Koongol, Wongal, Wongorr and a virus in the Corriparta serological group. The most important finding of these studies is that MVE displays as annually recurrent pattern of activity with a peak seasonal transmission rate at the end of the wet monsoon. This is the first definition of a probable endemic focus of MVE activity in Australia. The major vector for the majority of the viruses isolated was, by inference, Culex annulirostris. However, Aedeomyia catasticta was implicated as a major vector of the Corriparta group virus.

A preliminary investigation of the ecology of arboviruses in the Derby area of the Kimberley region, Western Australia.

A survey of mosquito populations in the Derby area of the Kimberley region, Western Australia, in March/April of 1977 yielded a total of 3,318 adult female mosquitoes. Fifteen taxa were represented, seven being new locality records for this area. Culex annulirostris was the dominant species, comprising 85.41% of the total catch. All mosquitoes collected were processed for virus isolation and thirteen strains of four (and possibly five) distinct arboviruses were obtained, all from pools of Culex annulirostris. These viruses include Murray Valley encephalitis, Ross River, Wongal, an untyped non-haemagglutinating member of the Koongol group and a virus which reacts to polyvalent antisera against the Anopheles A and B groups. With the exception of Ross River, all these viruses had been previously isolated from the Ord River Valley, some 500 km to the north-east. Comparison of virus isolations in the Ord Valley and Derby supports the suggestion that both sites share a common viral flora. Both also display an exceedingly high overall isolation rate (approximately 20% for Cx. annulirostris pools). Such comparisons suggest that a number of arboviruses transmitted by Cx. annulirostris are active throughout the Kimberley region and have peak isolation rates at the end of the wet season. Further studies are needed to fully define these viral cycles.