Effectiveness and Cost-Efficiency of Control of the Wild Rabbit, Oryctolagus Cuniculus (L.), By Combinations of Poisoning, Ripping, Fumigation and Maintenance Fumigation

An experiment compared effectiveness, cost and cost-efficiency of factorial combinations of the four commonly used methods of rabbit control on grazing properties in the Southern Tablelands of eastern Australia. Sixteen different treatment combinations were applied to 32 sites. The treatments comprised initial control, applied over four months, followed by repeated maintenance control on half the replicates, applied after intervals of 2,6 and 12 months. Initial control comprised no treatment, or poisoning (P) with sodium monofluoroacetate (1080), or warren-ripping (R), or chloropicrin pressure fumigation (F), or combinations of these (P+R, P+F, R+F, P+R+F). Maintenance control consisted of phosphine-diffusion fumigation (M). Indices of rabbit abundance were compared one month before treatments were implemented. Treatment effects were assessed one month after completion of the initial control, and one and 5-6 months after the three maintenance controls, and additionally nine months after the second maintenance control. Control combinations that were highly effective and cost-efficient included both warren-ripping and maintenance treatment. Poisoning prior to warren-ripping, or fumigating subsequently, or both, improved effectiveness and cost-efficiency. Warren-ripping interacted positively with one or more subsequent fumigations, improving effectiveness and cost-efficiency non-additively. Control combinations that excluded warren-ripping were ineffective and cost-inefficient, and one combination interacted negatively. Single treatments of poisoning or fumigation were cost-inefficient, allowing rabbits to recolonise rapidly to densities higher than original. Only multiple combination treatments or repeated applications were highly effective and cost-efficient; single applications of any method were inefficient and costly. The most effective and cost-efficient combination comprised the maximum six applications including ripping and maintenance treatment, namely P+R+F+M. The high effort and expenditure on the initial control resulted in high effectiveness and cost-efficiency, which maintenance control sustained at low cost. Maintenance treatments sustained or achieved effective control of rabbits; the cost of maintenance treatments halved on each repetition.

Cloning, genomic organization, and osmotic response of the aldose reductase gene

Diverse organisms accumulate organic osmolytes to adapt to hyperosmotic stress. The molecular basis of eukaryotic gene osmoregulation remains obscure. Aldose reductase [AR; alditol:NAD(P)+ 1-oxidoreductase, EC 1.1.1.21], which catalyzes the conversion of glucose to sorbitol (an organic osmolyte), is induced in renal medullary cells under hyperosmotic conditions. Elevated extracellular NaCl increases AR mRNA transcription in PAP-HT25 cells, a cell line derived from the rabbit renal papilla. We have cloned and characterized the rabbit AR gene to determine how it is regulated by hyperosmolality. The length of the gene, not including 5' or 3' flanking regions, is approximately 14.7 kilobases (kb) organized into 10 exons and 9 introns. The transcription start site is 36 base pairs upstream of the initiator methionine codon. A 5-kb fragment containing approximately 3.5 kb of 5' flanking region was isolated. The 3.5-kb sequence was examined for basal promoter activity and hyperosmotic response in luciferase reporter gene constructs. A 235-base-pair fragment (base pairs -208 to +27) was able to drive the downstream reporter gene in transfected PAP-HT25 cells under isoosmotic conditions (300 mosmol/kg of H2O). When this fragment plus the remaining upstream sequence (from approximately base pair -3429 to base pair +27) was used, cells in hyperosmotic medium (500 mosmol/kg of H2O) showed about 40-fold induction of luciferase expression compared with cells in isoosmotic medium. The upstream fragment (from approximately base pair -3429 to base pair -192) also conferred osmotic response to a heterologous promoter (B19). This finding evidences putative osmotic response element(s) (OREs) within a specific DNA fragment in a eukaryotic genome. Identification and characterization of OREs within this fragment and their associated trans-acting factors should reveal the molecular mechanisms of gene regulation in osmotic stress.

Water channel vesicles from toad urinary bladder contain a family of proteins present in other tissues

Antidiuretic hormone (ADH) stimulation causes the fusion and subsequent retrieval of cytoplasmic vesicles containing water channels (WCV) with the apical membrane of toad bladder granular cells. Previously, we showed that purified WCV contain 12 major protein bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. To identify various WCV proteins, we screened a panel of mouse monoclonal antibodies and characterized an immunoglobulin G1 monoclonal antibody, 5E5, that recognizes integral membrane WCV proteins of 38, 33, and 31 kDa. Immunocytochemistry and Western blot analyses show that 5E5 binds to multivesicular body endosomes shown previously to contain ADH water channels. In addition, 5E5 recognizes these proteins in selected cells of the skin, intestine, liver, kidney, spleen, and lung. However, 5E5 does not appear to recognize components of the water channel itself. We conclude that WCV contain several membrane proteins recognized by 5E5 that are present in certain cells of the other organs. Monoclonal 5E5 provides a probe to determine the structure and function of these endosomal proteins as well as their role in the ADH water permeability response.

Some epidemiological features of the human T-cell lymphotropic virus type I (HTLV-I) and ATL in Nigerians

With a seroprevalence rate (SPR) of 6%-10% among healthy adult blood donors (ABD), Nigeria and other African locales represent an endemic zone for HTLV-I. We studied SPR in patients with leukaemia, lymphomas, solid tumours, and chronic disorders, as well as in groups of men and women with varying sexual lifestyles. Serum specimens were screened with ELISA and then confirmed with Western blot (WB). Sexual practices were investigated among volunteers of different sexual backgrounds by means of a questionnaire. Female prostitutes (FP) (13.0%) and patients with sexually transmitted diseases (STDP) (16.7%) had the highest SPR while a low rate occurred in religious celibate males (RCM) but not in religious celibate females (RCF) (11.8%). Heterosexual activity as well as geographical location of the place of birth constituted the most important risk factors for HTLV-I. HIV antibodies were demonstrable in none of the study subjects. ATL was associated with 100% SPR (4/4) while SPR in other clinical states were not different from normal. Western blot profile was rarely of strong poly band but more frequently of weak oligo band pattern with absent or weak p19 compared to p24. Only 18% of non Hodgkin's lymphoma in Ibadan, Nigeria was seropositive compared to 50% and > 60% in Japanese and Caribbean endemic zones respectively. The high SPR and aberrant WB profiles indicate reactivity to HTLV-I and to an HTLV-II-like activity, probably a new virus in the region. Excluding the aberrant WB profile, SPR based on HTLV-I-related profile was 3.8%-4.8% in ABD, 13% in FP, 10% in STDP, 1.9% in RCM, 0% in RCF, and 25% in ATL patients. The HTLV-II-related profile showed no such heterosexual association, but occurred in 75% of ATL patients. HTLV-I and probably and an HTLV-II-like virus appear to play a role in STD and lymphoma epidemiology in Nigeria.

Frequency of adult T-cell leukaemia/lymphoma and HTLV-I in Ibadan, Nigeria

Sera from a small sample of adult blood donors, healthy school children and patients with lymphoma, leukaemia, non-haematologic cancer, congenital and inflammatory disorders from Ibadan, Nigeria were screened for HTLV-I antibody by an enzyme-linked immunoabsorbent assay and confirmed by investigational Western blot. Seventy-nine of 236 positively screened samples could not be tested for confirmation. Seropositive reactivity was observed in nine of 123 blood donors, and 3 of 46 healthy school children but banding patterns on Western blot were often sparse. Among non-Burkitt's non Hodgkin's lymphoma patients six of 30 were HTLV-I positive including four of four with clinical features of adult T-cell leukaemia (ATL). Other clinical conditions had a frequency of positivity indistinguishable from healthy donors. Western blot patterns ranged from strong with multiple bands, which were uncommon, to those with only p24 and p21 envelope positive which were frequent. Given the relative paucity of clinical ATL and the unusual Western blot patterns the true rate of HTLV-I infection may be lower than estimated. It is possible that a cross-reactive HTLV-I-like virus accounts for this pattern.

Geographical distribution of acute lymphoblastic leukaemia subtypes: second report of the collaborative group study

Childhood acute lymphoblastic leukemia (ALL) T and B precursor subtypes have been identified by standardised immunophenotyping in different geographic and ethnic settings. Comparison of the relative frequencies and estimated incidence rates of the major subtypes indicates very similar values, with the striking exception of black childhood populations in Africa in which there appears to be a significant and selective deficit in the incidence of the common (B-cell precursor) subset of ALL. There is suggestive evidence for a similar bias in ALL subtypes in South Africans of mixed ethnic origin and in Mapuche Indians from Chile. Several interpretations of these data are possible but the one favoured attributes these differences primarily to socio-economic factors and patterns of infection in infancy.

Inheritance of Acquired-Immunity to Myxomatosis

Male domestic rabbits mating after recovering from myxomatosis may transmit immunity to progeny born to the female in the next seven months, including progeny sired by other males lacking immunity (Sobey and Conolly 1986). In wild rabbits, Oryctolgus cuniculus (L.), we observed similar enhanced immunity in progeny of immune sires. The inherited immunity relates to the prior time of infection of the sire, and appears to be non-genetic; it complements genetic resistance and may persist into the progeny's reproductive lifetime. Inherited acquired immunity may reduce the effectiveness of myxomatosis in some wild rabbit populations.

Continuous in-vitro cultivation of Plasmodium falciparum in Ibadan: solutions to scientific and logistical problems

The technique of continuous in-vitro cultivation of Plasmodium falciparum has not been widely applied in malaria-endemic areas, due to scientific as well as purely logistical problems. Methods for solving or coping with these problems are described. They have already proved effective for over 4 years. The parasites harvested have been satisfactory, as judged by reproducible logarithmic growth curves and normal morphology in Leishman-stained smears as well as phase-contrast microscopy of wet-preparations. They have also been successfully used as antigen sources in the malarial fluorescent-antibody test and to investigate enhanced platelet aggregation in experimental malaria.

Genetic-Resistance to Myxomatosis in Australian Wild Rabbits, Oryctolagus-Cuniculus (L)

We examined the role of genetics of rabbit populations in the development of resistance to myxomatosis. We compared the responses of progeny from rabbit populations of Australian arid, mediterranean and subalpine regions when challenged at two ambient temperatures by plaque-purified virus of two myxoma strains of contrasting virulence, Uriarra and Lausanne. Wild rabbit populations have diverged in genetic resistance to myxomatosis since the rabbit was introduced to Australia 125 years previously. Founder effects and natural selection are possible causes. Rabbits from the warm dry regions died of Lausanne strain infection more slowly than rabbits from the cool moist region. Genetic resistance to myxomatosis probably diverged regionally as epizootics selected rabbit populations during the 34 years since the myxoma virus was introduced. Adaptation of rabbit populations to different environments might also have contributed to diverging resistance. Mortality was similar among regional groups and did not correlate with survival time, suggesting either polymorphism within populations, a prerequisite of natural selection, or variation in non-genetic immunity. Warmer conditions did not affect mortality but extended survival times. Therefore myxoma strains predominating in warm regions may be more virulent than those in cooler regions. Mean temperature may cause levels of genetic resistance to vary among regions. Mortality rates were less than those observed previously. Uriarra strain killed < 5% of infected rabbits compared to 35% previously. Lausanne strain killed 88%, formerly 98%. Selection during storage or plaque-purification may have decreased viral virulence, and recent natural selection may have increased genetic resistance of rabbits to myxomatosis.

Environmental and Genetic Influences on Growth of the Wild Rabbit, Oryctolagus-Cuniculus (L) in Australia

Environmental variation caused more variation in the growth rates of wild rabbits than did genetic divergence among populations in three climatic regions in Australia. The growth of various parts of the body responded to different environmental influences. Growth of the body core of kittens varied with the number of littermates. Growth of the pes varied with ambient temperature and the number of littermates. Growth of the pinnae, organs with special thermoregulatory function, was affected markedly by ambient temperature. Growth rates in regional rabbit populations differed consistently in two generations, manifesting differences in physiology and possible genetic divergence. Sub-alpine rabbits grew faster in body length and head length than did rabbits of mediterranean and arid climates. The extremities of mediterranean rabbits grew slower than those of arid and sub-alpine rabbits. The regional variation in growth physiology was determined either by persisting influence of the field environments transmitted maternally through two generations, or by genetic divergence of populations since the few progenitors were introduced to Australia 125 years previously.

Haemolytic anaemia associated with Nigerian barbecued meat (red suya)

Five cases of haemolytic anaemia occurring in male Nigerians following the ingestion of spiced barbecued meat (suya) are described. Although suya is a popular food item in various parts of Nigeria, all five patients described in this report had consumed a special brand, called red suya, purchased from vendors at a popular road junction between the cities of Lagos and Ibadan. Ingestion of the culprit suya sample was followed within 24 h by malaise and fever, while passage of dark-coloured urine and jaundice followed 1-3 days thereafter. Glucose-6-phosphate dehydrogenase (G6PD) deficiency was demonstrated by a fluorescent screening test in all cases, while the enzyme phenotype was shown to be GdA- in all four cases studied by starch-gel electrophoresis, thus suggesting that G6PD deficiency was a predisposing factor in the cases reported in this series. The haemolytic disease was self-limiting and full recovery followed in all cases. In view of the markedly circumscribed range from where the patients originated, the culprit agent responsible for the haemolytic disease is believed to be a recently introduced food additive that is probably accessible only to a limited number of suya vendors.

Recent advances in chemotherapy of the lymphomas: a review

A review of some of the developments over the last two decades in the field of chemotherapy of the lymphomas is provided. The evolution of the current treatment regimens through clinical trials is emphasized, and the need to develop a similar approach to cancer chemotherapy in African treatment centres is advocated. In view of their different natural histories, non-Hodgkin's lymphoma (NHL) of 'favourable' and 'unfavourable' histologic variants need to be treated differently. While the former type of NHL need only a non-myelosuppressive chemotherapy, the latter would benefit from intensive chemotherapy involving the use of adriamycin and cytosine arabinoside, which appear to have salutary effects in this form of NHL. Burkitt's and Hodgkin's lymphomas are both highly curable forms of cancer and indications are given in support of further improvement in their current chemotherapeutic management. As over 50% of adequately treated lymphoma patients are likely to experience prolonged survival, more attention is now being directed to factors contributory to their quality of life. Thus, some complications of chemotherapy and their prevention are reviewed.

Osteopetrosis in a Nigerian woman--a case report

A case of osteopetrosis complicated by chronic osteomyelitis of the mandible, pathological fractures, pancytopenia and splenomegaly is presented. Family studies revealed a dominantly inherited pattern.

Iatrogenic and idiopathic acute myelogenous leukemia: a comparison of clinical features and treatment complications

We have compared the clinical and laboratory features as well as treatment complications observed in 6 patients with iatrogenic acute myelogenous leukemia (I-AML) with those of 26 patients with idiopathic acute myelogenous leukemia (AML). I-AML patients were significantly younger and their disease appeared less virulent on admission than in the AML patients. Following identical chemotherapy, hemorrhagic complications and the need for platelet support were found to be similar for both groups. Major infections, including systemic candidiasis and Gram-negative septicemias, occurred 3 times more frequently among I-AML than AML patients. More marked suppression and delayed regeneration of the bone marrow also occurred in I-AML patients. These observations and other factors, such as post-splenectomy state and inherent immune deficiency among surgically staged lymphoma patients as well as radiation induced immunologic impairment, may have contributed to the increased propensity to develop infection observed in this group of patients. Five of the 6 I-AML and 17 of the 26 AML patients achieved remission. We attribute the satisfactory outcome in our I-AML patients to treatment in a protective environment and availability of facilities for hematologic supportive care.

Water Physiology and Nutrition in Fluctuating Populations of Rattus-Colletti in Monsoonal Northern-Territory, Australia

During wet and dry seasons and transitions of the monsoonal cycle, rates of water turnover and nutritional variables were measured on a population of Rattus colletti which fluctuated between extremes of high and low abundance. Rate of water turnover (RWT in millilitres per day) and body weight ( W, in kilograms) were related allometrically: RWT = aW*O.742 � 0.061, where a varied between seasons and sexes. Seasonal rates of water turnover were consistent with physiological adaptation in R. colletti to seasonal aridity. Rate of water turnover correlated with seasonal hydric regime, varying by a factor of 3.5 between dry and wet seasons. During the wet season, low body weight and lack of breeding seemed to be caused by flooding and its physical and social consequences. During dry season aridity the rats were short of food and water, but not in a dry season when rain fell and breeding ensued. Reproduction increased requirements for food and water in both sexes. Juveniles had relatively high requirements, and shortages appeared to retard growth. Very large populations resulted from prolific breeding after dry season rain had sustained high consumption of food and water on the riverine plains, the dry season habitat. Population decline resulted from very high wet season rainfall followed by a rainless dry season when food and water intakes were depressed, probably because the previous rainfall pattern reduced the availability of sedge corms, the dry season source of food and water. This climatic pattern recurred in the next wet and dry seasons, reinforcing the effects on R, colletti, which became rare for several years on both riverine systems studied.

Prospective studies on Hodgkin's disease in Ibadan--a preliminary report

A preliminary report of a prospective study of Hodgkin's disease (HD) is provided, based on clinical and laboratory findings on 21 patients seen between July 1978 and December 1979 at the University College Hospital (UCH), Ibadan. Staging procedure was minimized to relatively simple surgical procedures like lymphangiography and percutaneous biopsy. Staging laparotomy was performed only in one case. Female patients were significantly older than males (P less than 0.05). Patients with lymphadenopathy were significantly older than those without (P less than 0.05), while those with systemic symptoms were significantly younger than those without. Eighteen (86%) of the patients presented with stage IV disease while 12 (57%) had the unfavourable histologic "mixed cellularity' or "lymphocyte depleted' variants. Systemic symptoms were present in 16 (76%) of patients. Fifty-three % of adequately treated patients showed poor response to chemotherapy. The prognosis of HD in Ibadan is on the whole unfavourable. A delineation of the prognostic factors is indicated.

Neoplastic diseases of the haemopoietic system in Ibadan: preliminary report of a prospective study

The clinical and epidemiological features of haemopoietic malignancies in Ibadan have been evaluated in this preliminary analysis on findings on 113 patients seen at the University College Hospital, Ibadan, Nigeria, from July 1978 to June 1981. Twenty-seven patients had acute myelogenous (AML), twenty-two acute lymphoblastic (ALL), thirty-one chronic myelocytic (AML), thirty-one chronic lymphocytic leukaemia (CLL), two had polycythaemia rubra vera (PRV) and one myelofibrosis (MF). Incidence rates (IR) of 0.9 X 10(-5) and 1.9 X 10(-5) were estimated for acute leukemia (AL) and all leukemia subtypes respectively. Chloroma occurred frequently in association with AML especially in childhood, and CLL in elderly patients (greater than 50 years) and ALL appeared to manifest unusually aggressive features in spite of apparently adequate chemotherapy. Some of these clinical and epidemiological features suggest deviant biology of some haemopoietic malignancies in Ibadan.

Management of malignant lymphoproliferative disorders of the nervous system

The frequency of involvement of the nervous system (NS) among 266 patients seen at the University College Hospital (UCH), Ibadan, with a diagnosis of malignant lymphoproliferative diseases (MLPD) was determined. Only one of these patients who had a solitary spinal-cord involvement by Hodgkin's disease (HD) was considered to have primary lymphoma of NS. In all other cases, NS was only secondarily involved by MLPD. This was most commonly observed in association with Burkitt's lymphoma and occurred in 49.3 and 67% of such patients who were previously untreated or previously treated, respectively. Nervous system (NS) involvement at presentation was much less commonly observed in non-Hodgkin's (NHL), HD and acute lymphoblastic leukaemia (ALL) at the rate of 6.7, 4.4 and 0% respectively of previously untreated patients. The NS was the site of relapse in 63.6, 43, 12.5 and 0% in BL, ALL, NHL and HD, respectively. Intra-cranial NS disease was identified as a poor prognostic feature as this was associated with a reduction of the probability of prolonged survival from 48% to less than 20% among patients with intra-cranial and/or extra-cranial disease in BL. Management of MLPD with high rate of NS involvement should include effective delivery of chemotherapy into CFS, both by direct injection intrathecally and through filtration across the blood-brain barrier following high-dose intravenous injection of agents like methotrexate or cytosine arabinoside.