Impact of peritoneal membrane function on long-term clinical outcome in peritoneal dialysis patients.

It is increasingly clear that peritoneal membrane transport status has clinical implications. The role of the peritoneum in dialysis delivery becomes paramount once residual renal function is lost, particularly as the membrane characteristics may change for the worse with time on treatment. These findings have several important implications: Clinicians need to take solute transport characteristics into account as they assess their patients. Adverse effects of high solute transport include reduced ultrafiltration, solute removal (in particular, sodium), and increased peritoneal protein losses. A need exists to replace lost residual renal function, not just with enhanced solute removal, but also with adequate salt and water removal. The interpretation of urea and creatinine clearances in anuric PD patients needs further consideration and validation. Hypoalbuminemia in PD patients will result from the combined effects of high protein losses, over-hydration, comorbidity, and malnutrition.

What really happens to people on long-term peritoneal dialysis?

BACKGROUND: Several risk factors for patients treated with peritoneal dialysis (PD) have now been identified. These include age, comorbid disease, nutritional status, loss of residual renal function (RRF) and high peritoneal solute transport. This is not the same, however, as knowing what actually happens to these patients, particularly in the long-term. The purpose of this review was to give as complete a description as is currently possible of the long-term PD patient. METHODS: The literature was surveyed for publications that provide longitudinal cohort data of either selected or unselected patient groups. Detailed data from the Stoke PD Study is presented in the context of these studies. Three principle aspects of what really happens to patients were considered: (1) death, both cause and mode of death; (2) technique failure, with reference to peritoneal function and how the cause of technique failure related to patient survival; and (3) evolution of clinically relevant parameters of patients on PD, such as nutrition and peritoneal function. RESULTS: Sudden death and debilitation were the predominant modes of death, with sepsis playing a contributory role. Debilitation was important regardless of co-existent comorbid disease, and time to death was not influenced by the mode of death. Predominant causes for technique failure remain peritonitis and ultrafiltration, the latter becoming more important with time on treatment. Technical failure is associated with poorer survival, particularly when due to multiple peritonitis or failure to cope with treatment. Cox regression demonstrated that whereas low albumin, loss of RRF and high solute transport predicted patient death, only high solute transport predicted technique failure. Longitudinal changes over the first five years of treatment included loss of RRF, increasing solute transport and following an initial improvement in nutritional state, a decline after two years. Patients surviving long-term PD (at least five years, N = 25) were characterized by prolonged RRF, maintained nutrition and lower solute transport in the medium term. CONCLUSIONS: Several studies of long-term PD in the literature now complement each other in providing a picture of what really happens to PD patients. The links between loss of solute clearance and poor peritoneal ultrafiltration combining to exacerbate sudden or debilitated death and technique failure are emerging. For PD to be successful as a long-term therapy, strategies that maintain nutrition and preserve peritoneal membrane function must be developed.

Perceptions of veterinary clinics and pest control companies regarding tick-related problems in dogs residing in Texas cities.

OBJECTIVE: To determine the extent and source of tick-related problems encountered by veterinary clinics and pest control company (PCC) clientele experiencing residential tick infestations in urban/suburban environments and to determine which tick-related diseases in dogs were diagnosed and treated at veterinary clinics. DESIGN: Cross-sectional survey. SAMPLE POPULATION: Veterinary clinics and PCC in Dallas/Fort Worth and Austin/San Antonio, Tex. PROCEDURE: Surveys were made into professionally printed booklets and mailed to participants. RESULTS: Dallas/Fort Worth and Austin/San Antonio clinics indicated that tick-related problems comprised 21 and 15%, respectively, of their canine-based business. The most frequently observed species was the brown dog tick. Tick infestations were most common during May through August. Immature tick populations were seen by the greatest number of clinics in May and June, and engorged female ticks were encountered most often in June and July. Ticks were most commonly found around homes and adjacent yards or lots. Greenbelts were perceived by all 4 study groups to be the principal place in the community where ticks were acquired by clients' dogs. Canine ehrlichiosis was the most common tick-related disease diagnosed and treated at clinics, followed by anemia caused by tick infestation. CLINICAL IMPLICATIONS: Identification of ticks is important, because different tick species transmit different disease agents and different ecologic factors may be associated with exposure and subsequent treatment. Knowledge of temporal activity patterns of ticks, where they are acquired and where populations become established, combined with improved cooperative efforts between veterinary clinics and PCC, would aid in more effective control and management of ticks.

Knowledge-based patient screening for rare and emerging infectious/parasitic diseases: a case study of brucellosis and murine typhus.

Many infectious and parasitic diseases, especially those newly emerging or reemerging, present a difficult diagnostic challenge because of their obscurity and low incidence. Important clues that could lead to an initial diagnosis are often overlooked, misinterpreted, not linked to a disease, or disregarded. We constructed a computer-based decision support system containing 223 infectious and parasitic diseases and used it to conduct a historical intervention study based on field investigation records of 200 cases of human brucellosis and 96 cases of murine typhus that occurred in Texas from 1980 through 1989. Knowledge-based screening showed that the average number of days from the initial patient visit to the time of correct diagnosis was significantly reduced (brucellosis-from 17.9 to 4.5 days, p = 0.0001, murine typhus-from 11.5 to 8.6 days, p = 0.001). This study demonstrates the potential value of knowledge-based patient screening for rare infectious and parasitic diseases.

Isolation of pathogenic Aspergillus species from commercially-prepared potting media.

Twelve commercially-prepared potting soils were screened for the presence of pathogenic Aspergillus species. Pathogenic Aspergillus species were isolated from 67% of the soils. A fumigatus was isolated from 42% and A. flavus and A. niger from 33%.

High pressure liquid chromatographic determination of zearalenone in chicken tissues.

A method is reported for the extraction and analysis of zearalenone in chicken fat, heart muscle, and kidney tissue by using high pressure liquid chromatography (HPLC). Zearalenone is extracted with acetonitrile, cleaned up with hexane, and extracted further with ethyl acetate. Zearalenone is determined by HPLC using a reverse phase radial compression separation system, an ultraviolet absorbance detector, and a mobile phase of acetonitrile-water (60 + 40) (v/v). Recoveries of zearalenone added at levels from 50 to 200 ng/g are in the range 82.6-95.1%.

Inhibition of pancreatic carboxypeptidase A: A possible mechanism of interaction between penicillic acid and ochratoxin A.

Penicillic acid and ochratoxin A are environmentally important toxic fungal metabolites (mycotoxins) that are synergistic in combination. The effects of penicillic acid on the pancreatic enzyme, carboxypeptidase A were investigated in vitro and in vivo. A broad range of inhibition in vitro of the enzyme by PA was demonstrated with a half-maximal inhibitory concentration equal to 1.1 x 10(-4) M PA. Inhibition of carboxypeptidase A was time and temperature dependent, and resulted in decreased conversion of parent ochratoxin A to the non-toxic metabolite, ochratoxin alpha. Studies in vivo demonstrated a penicillic acid-dependent inhibition of pancreatic carboxypeptidase A activity in the mouse and the chicken following multiple oral exposure. It is postulated that the mode of toxic interaction of the two mycotoxins may be due, in part, to impaired detoxification of ochratoxin A through penicillic acid depletion of carboxypeptidase A activity.

A high pressure liquid chromatographic method for the analysis of zearalenone in chicken blood.

A high pressure liquid chromatographic (HPLC) method is described to determine zearalenone in chicken blood. Samples are extracted with acetonitrile, followed by a hexane cleanup procedure and extracted further with ethyl acetate. The analysis of zearalenone is by HPLC using a reverse phase radial compression separation system, an ultraviolet absorbance detector and a mobile phase of acetonitrile-water 60:40 (v/v). Recoveries of zearalenone in blood at levels of 50-200 ng/ml are in the range of 66.8-72.6%.

An experimental infection of Trypanosoma cruzi in striped skunks (Mephitis mephitis).

Four adult (3 male, 1 female) captive-raised, decented, striped skunks (Mephritis mephitis) were infected experimentaly with a field strain (Texas-Tulane) of Trypanosoma cruzi, originally isolated from a naturally-infected dog. Two skunks were injected intravenously with approximately 4.5 x 10(6) viable T. cruzi trypomastigotes. Two skunks were inoculated per os and per conjunctivum with 10 ml of phosphate buffered saline containing macerated, T. cruzi-infected triatomine intestines and intestinal contents. The skunks had minimal clinical manifestations with no mortalities occurring during 46 days post-exposure. Sera from all skunks were positive at 24 days post-inoculation (PI) by the direct and latex agglutination tests. Blood cultures from the 4 skunksd were positive for T. cruzi at day 24 PI and 3 were positive at day 46 PI. All skunks had mild to moderately severe chronic granulomatous myocarditis of the atria and ventricles. Typical T. cruzi amastigotes were present within myocardial fibers in 3 of 4 skunks.

Accidental exposure of veterinary students to rabies.

Accidental exposure to rabies occurred in more than 200 veterinary students at Texas A&M University from 1970 to 1977. Few of the animals to which the students were exposed had typical signs of rabies prior to the exposures. An accelerated preexposure rabies prophylaxis program coupled with retention of suspect tissues suitable for fluorescent antibody procedures has reduced the number of postexposure prophylaxis series.

Semen evaluation in capuchin monkeys (Cebus apella).

Semen from 3 adult male capuchin monkeys (Cebus appella) was collected and evaluated, utilizing an electroejaculator and different collection media. In the first 24 samples collected, no liquid fraction was found. Procedures were then directed toward liquefying the entire coagulum by enzymes for semen evaluation. The enzyme system first utilized consisted of varying percentages of trypsin in 2.5% dextrose in half-strength lactated Ringer's solution. Because of high spermatozoan abnormalities using this mixture, a new enzyme solution was used. This solution consisted of 1% pronase in Eagle's medium, containing Earles' salts. At the end of the experiment, natural mating was allowed. The semen collected from the vagina revealed similar consistency, volume, and sperm concentration when compared with artificially collected samples.

A spontaneous neuropathy of free-ranging Japanese macaques.

Thirteen cases of a spontaneous neuropathy were observed among 150 free-ranging Japanese snow monkeys (Macaca fuscata). Necropsy of 4 individuals revealed lesions in the peripheral and central nervous systems. Pathologic changes were associated with ingestion of coyotillo berries (Karwinskia humboldtiana).