Pet ownership increases human risk of encountering ticks.

We examined whether pet ownership increased the risk for tick encounters and tickborne disease among residents of three Lyme disease-endemic states as a nested cohort within a randomized controlled trial. Information about pet ownership, use of tick control for pets, property characteristics, tick encounters and human tickborne disease were captured through surveys, and associations were assessed using univariate and multivariable analyses. Pet-owning households had 1.83 times the risk (95% CI = 1.53, 2.20) of finding ticks crawling on and 1.49 times the risk (95% CI = 1.20, 1.84) of finding ticks attached to household members compared to households without pets. This large evaluation of pet ownership, human tick encounters and tickborne diseases shows that pet owners, whether of cats or dogs, are at increased risk of encountering ticks and suggests that pet owners are at an increased risk of developing tickborne disease. Pet owners should be made aware of this risk and be reminded to conduct daily tick checks of all household members, including the pets, and to consult their veterinarian regarding effective tick control products.

Lymphocytotoxic antibodies in leukemic patients treated with bone marrow transplantation.

Lymphocytotoxic antibodies were studied sequentially in a series of 42 patients with leukemia who received a bone marrow graft. Of these patients, 38% had cytotoxic antibodies before bone marrow transplantation (BMT). After BMT the antibody status changed with time, but 62% of the patients had antibodies at some time after BMT. During the first 10 weeks after BMT, 40% of the patients had antibodies. Thereafter the frequency rose to 50% and remained at that level beyond one year after BMT. In successful grafts the gamma globulins are of donor origin six months after BMT; thus donor B cells are capable of forming lymphocytotoxic antibodies even when the immune system is suppressed by cyclosporine. The antibodies had recognizable HLA specificity in about half the cases before and after BMT. When donor and patient were HLA-identical, HLA specificity did not correspond to donor/recipient antigens. In two cases in which the donor was matched for only one haplotype, antibodies formed by recipient cells, active against donor HLA antigens, were found.

Study of the HLA system in Burkitt's lymphoma.

Seventy-eight patients with Burkitt's lymphoma and seventy controls from Ghana were typed for HLA-A, B, C and DR antigens, to determine whether there is an association between the HLA system and Burkitt's lymphoma. Increased relative risk was observed in Burkitt's lymphoma patients with DR7, HLA-A1 and B12(BW44).

HLA-DR7 association with African Burkitt's lymphoma.

Association between HLA-DR7 and Burkitt's lymphoma previously reported has been confirmed by a second study. Analysis of additional data from a second study of 33 Ghanaian patients with African Burkitt's lymphoma and 54 Ghanaian controls matched for age and ethnic origin showed that 39.4% of cases, but only 14.8% of controls, had HLA-DR7 (p less than 0.01). The relative risk of 3.7 is similar to that observed in the earlier study (3.3). Combining the earlier and present studies, analysis of clinical data from 94 patients with Burkitt's lymphoma and 116 controls shows the relative risk of Burkitt's lymphoma among individuals with HLA-DR7 was 3.4 (p less than 0.001). There was an increased relative risk of the disease associated with HLA-DR7 in: patients under 10 years of age; and patients with advanced stages of disease (Stage III or IV). However, comparison of relative risks by sequential analysis of 2 X 2 tables showed that these differences by age and stage were not statistically significant.

One haplotype matched bone marrow grafts: an investigation using the HLA system as a marker of cellular origin.

HLA antigens were used as markers to study the lymphocyte population in 31 patients with leukaemia, treated with a one-haplotype matched bone marrow transplant (BMT). In 24 patients substained engraftment was achieved and the recipient was repopulated with B and T lymphocytes of donor HLA type. Repopulation occurred at the same rate for lymphocytes of the B and T cell classes, usually within 2 weeks of grafting. In two additional cases bone marrow engraftment was successful but the lymphocyte population was chimeric and cells of both donor and host HLA type were present in the recipient for many weeks. Three patients relapsed after engraftment and peripheral blood lymphocytes were exclusively of host or donor HLA type, or a chimeric population was present. In one chimeric case, peripheral blood T lymphocytes were of donor origin, and B lymphocytes were of host origin. Mononuclear cells in the bone marrow were of host HLA type. The use of the HLA system as a marker is a useful additional approach to determine engraftment or chimerism following an allogeneic one haplotype matched bone marrow transplant.

Hypertension as cause of end-stage renal disease: lessons from international registries.

The incidence of hypertension as cause of ESRD has doubled in the ERA-EDTA Registry in the past two decades, going from 7 to 13%. It is very possible that this is not a real increase in the incidence of hypertension as cause of ESRD, but rather a consequence of greater acceptance of older patients, a phenomenon that has simultaneously occurred. There are geographic differences in the incidence of hypertension as cause of ESRD, from 6% in Japan to 28.5% in the U.S., and 13% in Europe. With the present data, it is impossible to know if these differences are real. The diagnostic criteria used are not uniform and a consensus would be necessary to establish uniform diagnostic criteria for nephrosclerosis or ischemic nephropathy. The percentage of patients starting renal replacement therapy (RRT) with unknown primary renal disease is very different in the U.S. and Europe. This could be a critical factor in explaining these differences. Survival of patients at 5 and 10 years with renal vascular disease did not improve from 1977 to 1989. The same occurs with survival of patients with standard primary renal disease, although this is better than that of patients with renal vascular disease. To interpret this lack of improvement in survival of patients over a decade, we must take into account that at the same time there has been a significant increase in the age of patients starting RRT. Therefore, when the population of patients of under 55 is analyzed, there is evidence that those starting treatment in the 80's have much better survival than those starting in the 70's. However, survival of patients with renal vascular disease continues to be poorer than that of patients with standard primary renal disease. This lower survival of patients with renal vascular disease seems to be related to higher cardiac mortality, which is in alignment with the diagnosis of hypertension as cause of renal failure.

Topographic sequence of outgrowth of corticospinal axons in the rat: a study using retrograde axonal labeling with Fast blue.

The retrogradely transported dye, Fast blue, was injected into cervical or lumbar segments of the spinal cord of rats during the first days of life in order to label the cell bodies of origin of the corticospinal tract which is growing down the cord during that period. The first corticospinal axons arrive at cervical levels immediately after birth and all arise from a circumscribed group of layer V pyramidal cells in a small region of dorsal parietal cortex. This same cell group provides the corticospinal projection to lumbar segments of the spinal cord, the axons reaching those segments at the end of the first postnatal week. The area of lumbar projecting cells undergoes relatively little expansion and no diminution during subsequent weeks and into adulthood. The area occupied by cortical cells projecting to the spinal cord expands during the first postnatal week, but the axons of all these additional cells do not appear to invade the lower sequents of the spinal cord. By the end of the first week, corticospinal cells can be labeled in a continuous sheet throughout most of the extent of the frontal, parietal and cingulate cortex. During the second and third postnatal weeks, the area sending axons to the upper levels of the spinal cord diminishes and large areas bereft of retrogradely labeled corticospinal cells appear: laterally, in lateral frontal and lateral parietal cortex; dorsally, at the border of frontal and parietal cortex; medially, in medial frontal and cingulate cortex. The more restricted adult pattern is established at the end of the third week. Hence, the first cortical axons to advance down the spinal cord are those that will innervate the lumbar segments in the adult. Later addition of corticospinal axons involves only those projecting to upper cord segments. Within this group there are those which will establish persistent connections from appropriate cortical areas and others that will shortly be eliminated from inappropriate areas.

How physicians can prevent medication errors: practical strategies.

To eliminate and reduce medication errors, health care organizations must develop a consistent approach that allows examination of errors in a supportive atmosphere with a bias toward preventing future errors rather than punishing past ones. Until improved systems are in place, physicians can help prevent many of the most serious medication errors by observing some basic safety practices, such as writing orders whenever possible and limiting verbal orders to urgent or emergency situations, writing clearly and neatly, and avoiding abbreviations.

Protozoan and viral infections of feral cats.

Identification of protozoan oocysts and serological tests were used to determine the prevalence of infections among 300 mainly adult feral cats in three different habitat types in south-eastern Australia. Oocysts of Isospora rivolta and Isospora felis were recovered from 3% and 4% respectively of 300 feral cat samples. Haemagglutination inhibition antibody to Toxoplasma gondii was detected in 20% of 75 cat sera tested. A high prevalence of specific antibody to feline panleukopaenia virus (79%) and feline calici virus (77%) was demonstrated but the prevalence of antibody to feline herpes virus was low (11%). 15 strains of feline calici virus were isolated from pharyngeal swabs. There were no other virus isolations from the 60 pharyngeal and rectal swabs taken. These viral and protozoan infections could not be linked with any obvious pathological conditions. Most cats were in good condition with light to moderate fat stores in depot areas. Limb fractures and other skeletal abnormalities occurred infrequently. Major tooth damage or absence of important teeth was evident in about 20% of 164 animals examined. There was no correlation between major tooth damage and poor body condition.

Helminth parasites and arthropods of feral cats.

The prevalence (%) of helminth parasites in 327 mainly adult feral cats from 3 habitat groupings in Victoria and New South Wales was determined. The cestodes Taenia taeniaeformis (33%) and Spirometra erinacei (33%) were common; Dipylidium caninum was rate (2%). The nematodes Toxocara cati (28%), Cyathospirura dasyuridis and Cylicospirura felineus combined (27%) and Aelurostrongylus abstrusus (14%) were common but their prevalence differed markedly between habitats. Ollulanus tricuspis (5%), Gnathostoma spinigerum (less than 1%) and an Acanthocephala, Onicola sp (19%), also occurred. Arthropod parasites were collected from 204 of these cats, Ctenocephalides felis (16%) and Echidnophaga spp. (28%) were common. Spilopsyllus cuniculi (3%) and Ctenocephalides canis and Nosopsyllus fasciatus (less than 1% each) were rare. Other rare ectoparasites were the louse, Felicola subrostrata (4%), the mites, Otodectes cynotis, Cheyletiella sp and a trombiculid (less than 1% each); and the tick lxodes tasmani (less than 1%). There was no correlation between degree of parasitism and general condition of the cats.