Clinical and pathologic findings in ferrets with lymphoma: 60 cases (1982-1994)

OBJECTIVE

To examine clinical and pathologic findings in 60 ferrets with lymphoma.

DESIGN

Retrospective case series.

ANIMALS

60 ferrets in which the diagnosis of lymphoma had been confirmed by means of histologic examination of biopsy or necropsy specimens.

PROCEDURE

Information including age, sex, coat color, history, clinical signs, clinicopathologic abnormalities, treatment, outcome, and results of histologic examination of biopsy and necropsy specimens were retrieved from medical records of ferrets with spontaneous lymphoma examined between 1982 and 1994 at the Massachusetts institute of Technology or private veterinary practices in 10 states. Classification of lymphoma was assigned according to the National Cancer Institute's working formulation for non-Hodgkin's lymphomas. Chi 2 Trend analysis was used to determine whether age was associated with history, clinical signs, hematologic abnormalities, stage, histologic grade, or outcome.

RESULTS

Acute onset, mediastinal mass, lymphocytosis, and multicentric distribution were linked with younger ferrets, and lymphopenia and survival longer than 2 months after diagnosis was associated with older ferrets. Twenty percent of ferrets in this study had cohabitated with another ferret with lymphoma. Chemotherapeutic efficacy was not evaluated.

CLINICAL IMPLICATIONS

Clinical and pathologic features linked with age should be considered when evaluating diagnostic and therapeutic options for ferrets with lymphoma.

Detrusor-sphincter dyssynergia

Detrusor-sphincter dyssynergia refers to failure of the urethral sphincter to relax during detrusor contraction. The cause is a central nervous system lesion located between the brain stem micturition center and the sacral spinal cord. This is an extremely rare condition in cats. It may be confused with a failure of urethral relaxation due to local urethral causes such as inflammation or edema. This article reviews detrusor-sphincter dyssynergia to allow the reader to distinguish this rare condition from more common conditions that prevent bladder emptying.

Pathophysiology of urethral obstruction

Obstructive uropathy refers to abnormalities in structure or function of the urinary tract caused by impairment of normal flow of urine, and the resulting local and systemic effects of that impairment. Clinic consequences of obstructive uropathy are associated with abnormalities in fluid balance, electrolyte metabolism, acid-base balance, and retention of metabolic wastes. These consequences are partly due to build up of intravesical, ureteral, and renal pressure, influx of leukocytes into renal parenchyma resulting in release of cytokines, and alterations in intravascular hemodynamics. This article discusses pathophysiologic mechanisms and consequences of obstructive uropathy in cats.

Fluoroquinolones in animal health

The fluoroquinolones are a series of synthetic antibacterial agents that are undergoing extensive investigation for both human and veterinary use in the treatment of a variety of bacterial infections. These agents work through the inhibition of DNA gyrase, interfering with the supercoiling of bacterial chromosomal material. As a result, these agents are rapidly bactericidal primarily against gram-negative bacteria, mycoplasma, and some gram-positive bacteria, with most having little to no activity against group D streptococci and obligate anaerobic bacteria. Resistance develops slowly and is almost always chromosomal and not plasmid-mediated. However, development of resistance to the fluoroquinolones and transfer of that resistance among animal and human pathogens have become a hotly debated issue among microbiologists. The fluoroquinolones are a current antimicrobial class whose use in veterinary medicine is being scrutinized. From a pharmacokinetic perspective, these agents are variably but well absorbed from the gastrointestinal tract and almost completely absorbed from parenteral injection sites, and they are well distributed to various tissues in the body. The fluoroquinolones are metabolized and renally excreted, with many of them having approximately equal excretion by the hepatic and the renal excretory systems. The primary toxicity observed at therapeutic doses involves the gastrointestinal system and phototoxicity, although at higher doses central nervous system toxicity and ocular cataracts are observed. Administration to immature animals may result in erosive arthropathies at weight-bearing joints, and administration of high doses to pregnant animals results in maternotoxicity and occasionally embryonic death. The fluoroquinolones are approved for indications such as urinary tract infections and soft tissue infections in dogs and cats and colibacillosis in poultry. Approval for bovine respiratory disease in the United States is being sought. Other indications for which the fluoroquinolones have been used in animal health include deep-seated infections, prostatitis, and other bacterial infections resistant to standard antimicrobial therapy.

Effects of age on the pharmacokinetics of single dose ceftiofur sodium administered intramuscularly or intravenously to cattle

The effects of maturation on the intravenous (IV) and intramuscular (IM) pharmacokinetics of ceftiofur sodium following a dose of 2.2 mg ceftiofur equivalents/kg body weight were evaluated in 16 one-day-old Holstein bull calves (33-53 kg body weight initially; Group 1) and 14 six-month-old Holstein steers (217-276 kg body weight initially; Group 2). Group 1 calves were fed unmedicated milk replacer until 30 days of age and were then converted to the same roughag/concentrate diet as Group 2. Groups 1-IV and 2-IV received ceftiofur sodium IV, and Groups 1-IM and 2-IM received ceftiofur sodium IM. Group 1 calves were dosed at 7 days of age and at 1 and 3 months of age; group 2 calves were dosed at 6 and 9 months of age. Blood samples were obtained serially from each calf, and plasma samples were analysed using an HPLC assay that converts ceftiofur and all desfuroylceftiofur metabolites to desfuroylceftiofur acetamide. Cmax values were similar in all calves, and were no higher in younger calves than in older calves. Plasma concentrations remained above 0.150 microgram ceftiofur free acid equivalents/mliter for 72 h in 7-day-old calves, but were less than 0.150 microgram/mliter within 48 h following IV or IM injection for 6- and 9-month-old calves. Intramuscular bioavailability, assessed by comparing the model-derived area under the curve (AUCmod) from IM and IV injection at each age, appeared to be complete. After IV administration, the AUCmod in 7-day-old and 1-month-old calves (126.92 +/- 21.1 micrograms.h/mliter and 135.0 +/- 21.6 micrograms.h/mliter, respectively) was significantly larger than in 3-, 6- and 9-month-old calves (74.0 +/- 10.7 micrograms.h/mliter, 61.0 +/- 17.7 micrograms.h/mliter and 68.5 +/- 12.8 micrograms.h/mliter, respectively; P < 0.0001). The Vd(ss) decreased linearly within the first 3 months of life in cattle (0.345 +/- 0.0616 L/kg, 0.335 +/- 0.919 L/kg and 0.284 +/- 0.0490 L/kg, respectively; P = 0.031), indicative of the decreasing extracellular fluid volume in maturing cattle. The ClB was significantly smaller in 7-day-old and 1-month-old calves (0.0178 +/- 0.00325 L/h.kg and 0.0167 +/- 0.00310 L/h.kg, respectively) than in 3-, 6- and 9-month-old calves (0.0303 +/- 0.0046 L/h.kg, 0.0398 +/- 0.0149 L/h.kg and 0.0330 +/- 0.00552 L/h.kg, respectively; P < or = 0.001). This observation may be indicative of maturation of the metabolism and/or excretion processes for ceftiofur and desfuroylceftiofur metabolites. The approved dosage regimens for ceftiofur sodium of 1.1-2.2 mg/kg administered once daily for up to 5 consecutive days will provide plasma concentrations above the MIC for bovine respiratory disease pathogens for a longer period of time in neonatal calves than in older calves. Peak plasma concentrations of ceftiofur and desfuroylceftiofur metabolites were no higher in neonatal calves than in more mature cattle, highly suggestive that peak tissue concentrations would be no higher in neonatal calves than in more mature cattle.

Evaluation of a single injection method, using iohexol, for estimating glomerular filtration rate in cats and dogs

OBJECTIVE

To evaluate the utility of a method for estimating glomerular filtration rate (GFR) after single IV administration of iohexol.

DESIGN

The plasma clearance of iodine (PCI), taken as the quotient of the administered dose of iodine (300 to 600 mg of l/kg of body weight) divided by the area under the plasma iodine concentration versus time curve determined by 4 methods (PCI1-PCI4). The results for PCI were compared with simultaneously obtained values for the urinary clearance of exogenously administered creatinine (CCr), a widely accepted method for the measurement of GFR in cats and dogs.

ANIMALS

Cats and dogs that were renal intact (n = 5 cats; n = 1 dog) or had renal mass reduced by partial nephrectomy (n = 5 cats; n = 7 dogs).

RESULTS

Values for PCI were closely related (R2 values ranged from 0.947 to 0.992; P < 0.0001 in all cases) to CCr. Despite this close correlation between CCr and PCI, the 95% confidence interval for the difference between PCI3 and CCr included values that exceeded 1.4 ml/min/kg, which represents 50% of the mean value for CCr in renal-intact cats.

CONCLUSIONS

Determination of PCI provided a reliable estimate of GFR in cats and dogs of this study. However, differences between 1 of the methods (PCI3) and CCr are clinically important, emphasizing the need to use more than simple linear regression analysis and correlation coefficients when attempting to validate new measurement techniques.

CLINICAL RELEVANCE

The determination of PCI provided a reliable estimate of GFR in cats and dogs of this study.

Clusters of lymphoma in ferrets

Cluster outbreaks of lymphoma and leukemia have been associated with viral infections in many species including humans, cattle, and cats. This study describes epidemiological, clinical, and pathological features of cluster outbreaks of lymphoma in multiferret households and examines and compares the Aleutian disease virus (ADV) and feline leukemia virus (FeLV) status of cases, ferrets at risk, and controls. Three ferret groups with 21 cases of histologically diagnosed lymphoma (12.6% cumulative incidence) and their cohabitants (n = 35) were examined and compared with three control groups (n = 52) of cohabitating ferrets without lymphoma. A familial distribution was observed in one group but most cases were not consanguinous. Ferrets greater than 3 years of age developed chronic disease in two of the groups and 2-year-old adults had acute disease in the remaining group. Lymphocytosis, splenomegaly, and lymphadenopathy were prominent features. Histologically, predominantly small noncleaved cell and polymorphous lymphoid lesions were observed. All of the ferrets with lymphoma that were tested for ADV and FeLV using serology or PCR were negative. The rate of ADV antibody among cases or ferrets at risk was not significantly different from controls. None of the cluster ferrets were seropositive for FeLV p27 antigen using a monoclonal ELISA. Infection with a novel ferret virus is suspected, but an etiological agent has not yet been identified.

The Adolescent Relapse Coping Questionnaire: psychometric validation

OBJECTIVE

The present study was undertaken to assess the factor structure and psychometric validity of the Adolescent Relapse Coping Questionnaire (ARCQ). The ARCQ is designed to assess alcohol and other drug abusing adolescents coping with situations providing temptations for alcohol and other drug use.

METHOD

This was a prospective longitudinal study of 136 (79 male) alcohol and other drug abusing adolescents who were an average of 16.9 years old. Consecutive admissions were recruited from two adolescent, inpatient alcohol and drug abuse treatment facilities. Subjects completed the ARCQ as part of a 1-year-posttreatment interview and were subsequently interviewed 2 years posttreatment.

RESULTS

Analyses yielded three coping factors which were evaluated for construct and criterion validity. Factor 1 contained generic cognitive and behavioral problem-solving strategies, Factor 2 represented self-critical cognitions and Factor 3 included abstinence-focused coping strategies. The factors had good internal consistency (alpha = .78 to .82) and collectively accounted for 40% of the variance in the principle components analysis. The abstinence-oriented coping factor was significantly correlated with current alcohol and drug use and measures of situation appraisal, and significantly predicted alcohol and drug use during the year following assessment.

CONCLUSIONS

The findings provide evidence for the psychometric validity of the ARCQ, provide convergent validation for the utility of the temptation-coping construct and further highlight differences between adult and teen addictive relapse.

Relationship between plasma creatinine concentration and glomerular filtration rate in dogs

Glomerula filtration rate (GFR), plasma creatinine concentration (CR), and plasma urea nitrogen concentration (BUN) were measured in 129 adult dogs with reduced renal mass. A preliminary examination of the relationship between CR and GFR was conducted, and the inverse model (GFR vs. 1/CR) was chosen for further evaluation. The slope of the regression of GFR on 1/CR which was computed from actual data was not statistically different from a theoretical regression line generated from the clearance equation. Evaluation of subsets of the population revealed no significant difference between male (n = 69) and female (n = 60) dogs on the slope of the regression equations. Diets differing in protein concentration (16% protein, n = 35: 21% protein, n = 75: 32% protein, n = 19) did not cause a significant difference in the slope of the regression equations. The regression equation and the confidence intervals generated in this study may be used to predict a probable range of GFR values from CR in individual dogs. Such values may be useful in adjusting drug dosages in dogs with renal disease. However, since the derived equation did not differ significantly from the theoretical inverse relationship between GFR and CR, it remains to be established whether the equation is advantageous.

Preadolescent conduct disorder behaviors predict relapse and progression of addiction for adolescent alcohol and drug abusers

Increased awareness of the heterogeneity among alcohol and drug abusers has led to examination of the influence of concomitant psychopathology on the course of addiction and addictive relapse. Research among adult alcohol and drug abusers has found a detrimental influence of comorbid psychopathology on treatment outcome. Evidence exists for prevalent comorbidity, in particular conduct disorder (CD), among clinical samples of teen alcohol and drug abusers. However, little information is currently available on the relation and influence of psychopathology on outcome after treatment for adolescent alcohol and drug abuse. The current study examines the relation between CD, as assessed by the extent of preadolescent CD behaviors occurring before the initiation of drug use, and outcome for 131 adolescents over 2 years after inpatient treatment for alcohol and drug abuse. Drawing on recent conceptualizations of the process of relapse and progression of addictive behavior, CD is hypothesized to influence the process of relapse by altering coping efforts and intentions and increasing exposure to potential relapse situations. Results reveal that the extent of preadolescent CD behaviors is positively related to alcohol involvement in the 2 years after treatment, and that much of this relation is accounted for by posttreatment cognitive coping, motivation for alcohol abstinence, interpersonal problems, and exposure to alcohol use. Contrary to expectations, preadolescent CD behaviors did not predict posttreatment drug use. These findings provide evidence for the influence of psychopathology on the process of relapse and progression of addiction after treatment for adolescent alcohol and drug abuse, and suggest that teens with early life CD behaviors may be at greater risk for continued alcohol abuse.

Single-nephron adaptations to partial renal ablation in cats

To evaluate remnant nephron hyperfiltration, cats underwent sham surgery (group 1, n = 6) or three-fourths nephrectomy (group 2, n = 6). Four to six weeks later, micropuncture studies demonstrated increases (P < 0.01) of single-nephron glomerular filtration rate (SNGFR) in group 2 (28.1 +/- 2.8 vs. 56.0 +/- 5.9 nl/min). In group 2 the mean estimated glomerular capillary pressure of 74.0 +/- 1.7 mmHg exceeded (P < 0.01) the value for group 1 (62.6 +/- 1.4 mmHg). The mean effective filtration pressure (EFPm) for group 2 (28.7 +/- 3.1 mmHg) was greater (P < 0.05) than that in group 1 (20.8 +/- 1.9 mmHg). Similarly, the mean ultrafiltration coefficient (Kf) in group 2 of 2.03 +/- 0.24 nl.min-1.mmHg-1 exceeded (P < 0.05) the corresponding value for group 1 of 1.35 +/- 0.06 nl.min-1.mmHg-1. Morphological studies demonstrated glomerular enlargement and mesangial matrix expansion in group 2 (P < 0.05). Proteinuria, as assessed by the urine protein-to-creatinine ratio, was increased (P < 0.05) after partial renal ablation. These results demonstrate that increases in SNGFR in feline remnant nephrons occur in association with glomerular hypertension, glomerular hypertrophy, expansion of mesangial matrix, and proteinuria, and furthermore, that the observed increases in SNGFR are attributable to an augmentation of EFPm and Kf.

A meta-analysis of nurse practitioners and nurse midwives in primary care

This meta-analysis was an evaluation of patient outcomes of nurse practitioners (NPs) and nurse midwives (NMs), compared with those of physicians, in primary care. The sample included 38 NP and 15 NM studies. Thirty-three outcomes were analyzed. In studies that employed randomization to provider, greater patient compliance with treatment recommendations was shown with NPs than with physicians. In studies that controlled for patient risk in ways other than randomization, patient satisfaction and resolution of pathological conditions were greater for NP patients. NPs were equivalent to MDs on most other variables in controlled studies. In studies that controlled for patient risk, NMs used less technology and analgesia than did physicians in intrapartum care of obstetric patients. NMs achieved neonatal outcomes equivalent to those of physicians. Limitations in data from primary studies precluded answering questions of why and under what conditions these outcomes apply and whether these services are cost-effective.

The effect of human IL-2-activated natural killer and T cells on graft-versus-host disease and graft-versus-leukemia in SCID mice bearing human leukemic cells

We have previously reported that xenogeneic lethal acute graft-versus-host disease (GVHD) was induced by transplantation of a mixture of human IL-2 activated natural killer (NK) and T cells into SCID mice conditioned with 4 Gy total-body irradiation (TBI), but not by IL-2-activated pure human T cells or NK cells. TBI and transplantation of the mixture of activated cells were both required to produce the lethal effect. We now report the effect of human IL-2 activated NK, T, or NK+T effector cells on the development of acute and chronic GVHD and GVL in SCID mice bearing human leukemic cells. Ten days after being inoculated i.v. with 2 x 10(7) human U-937 or K-562 leukemic cells, SCID mice, hereafter termed hu-leukemic mice, were radiated with 4 Gy TBI and transplanted i.v. with 5 x 10(7) human IL-2-activated NK, T, or NK+T effector cells. Hu-leukemic control mice received neither TBI nor effector cell transplantation. Acute GVHD-positive control SCID mice were transplanted with 5 x 10(7) H-2-incompatible C57Bl/6 splenocytes following 4 Gy TBI. The mice were observed for signs of GVHD and leukemia for 90 days. Twenty of 20 non-effector cell-transplanted control hu-leukemic mice developed signs related to leukemia and died with leukemic infiltration in the brain, liver, kidney, and lung 50-65 days after inoculation. Flow cytometry (FC) demonstrated 21-89% human leukemic cell infiltration in the bone marrow. Fourteen of 14 hu-leukemic mice transplanted with NK+T effector cells did not develop signs of advanced leukemia but died within 17 days of acute GVHD. FC demonstrated no human leukemic cells in their marrow. Twelve of 15 and 18 of 25 hu-leukemic mice transplanted with either NK or T cells survived 90 days without any evidence of symptomatic leukemia (P < 0.01 compared with non-effector cell-transplanted groups). NK-transplanted hu-leukemic animals experienced mild-to-moderate acute GVHD during the first 10-20 days posttransplantation, but gradually recovered and did not develop chronic GVHD. Hu-leukemic animals transplanted with T effector cells manifested no signs of leukemia or acute GVHD but chronic GVHD skin lesions appeared 80-90 days after transplantation. We conclude that acute GVHD, chronic GVHD, and GVL are associated but separable phenomena.

Plasma and urine disposition and dose proportionality of ceftiofur and metabolites in dogs after subcutaneous administration of ceftiofur sodium

Nine male dogs (10.3-13.5 kg body weight) were randomly assigned to three groups of three dogs each and administered ceftiofur sodium subcutaneously as a single dose of 0.22, 2.2, or 4.4 mg ceftiofur free acid equivalents/kg body weight. Plasma and urine samples were collected serially for 72 h and assayed for ceftiofur and metabolites (derivatized to desfuroylceftiofur acetamide) using high-performance liquid chromatography. Urine concentrations remained above the MIC90 for Escherichia coli (4.0 micrograms/mL) and Proteus mirabilis (1.0 micrograms/mL) for over 24 h after doses of 2.2 mg/kg (8.1 micrograms/mL) and 4.4 mg/kg (29.6 micrograms/mL), the interval between treatments for ceftiofur sodium in dogs, whereas urine concentrations 24 h after dosing at 0.22 mg/kg (0.1 mg/Ib) were below the MIC90 for E. coli and P. mirabilis (0.6 microgram/mL). Plasma concentrations were dose-proportional, with peak concentrations of 1.66 +/- 0.0990 micrograms/mL, 8.91 +/- 6.42 micrograms/mL, and 26.7 +/- 1.07 micrograms/mL after doses of 0.22, 2.2, and 4.4 mg/kg, respectively. The area under the plasma concentration versus time curve, when normalized to dose, was similar across all dosage groups.

Distribution of titanium and vanadium following repeated injection of high-dose salts

Titanium and its alloy of 6% aluminium and 4% vanadium are used extensively in orthopedic and dental surgery. However, in conditions of motion leading to wear, there is significant generation of wear products with deposition of black debris in the tissue. The questions remain as to how much of this debris is generated and to where it is transported. Previous studies have been hampered by low levels of detected elements giving values just above the background levels found in normal tissue and body fluids. The purpose of these experiments was to increase the body burden of titanium and vanadium by injecting larger doses of titanium and vanadium salts over an extended period of time. Each animal (Syrian hamster) received 100 micrograms of each element once a week for six weeks. The hamster was sacrificed on the seventh week and body fluids and tissue harvested. The results indicate that in the experimental animals there was transport of vanadium with levels above control in urine, plasma, liver, spleen, and the mineralized portion and organic portion of bone. Titanium had less transport but still showed levels in the experimental animals in plasma, kidney, liver, spleen, and both phases of bone above those in the control animals. Neither element was found above control levels in lung or red blood cells. The levels of titanium and vanadium in control bone were high, possibly indicating bone as a site for storage and accumulation of these elements when encountered in the activities of daily living.

Stress, vulnerability and adult alcohol relapse

OBJECTIVE

Alcoholics experiencing highly threatening or chronic psychosocial stress following treatment are more likely to relapse than abstaining individuals not experiencing such stress. Expanding upon this stress-relapse hypothesis, we predicted that individual risk and protective characteristics would contribute to vulnerability to relapse in alcoholic men confronted with significant life adversity. The present investigation examined the relationship between psychosocial vulnerability and return to drinking.

METHOD

A group of abstinent male alcoholics (N = 67) who experienced marked life adversity that posed a severe and/or chronic threat participated in this study. Men completed a psychosocial assessment first as an inpatient in treatment for alcohol dependence, and again at 3 months and 1 year following discharge.

RESULTS

Among alcoholic men exposed to severe psychosocial stressors, those with higher composite psychosocial vulnerability scores were more likely to subsequently relapse than those with lower vulnerability scores. Additionally, men who improved in psychosocial functioning following treatment had better outcomes than men whose vulnerability increased. In particular, coping, self-efficacy and social support most consistently predicted relapse among this sample of severely stressed abstaining alcoholics.

CONCLUSIONS

These findings supported the stress-vulnerability model of relapse. Results indicated that improvement in psychosocial domains (e.g., coping skills, social networks, perceived ability to tolerate relapse-risk situations) enhanced the ability of these men to remain abstinent despite severe stress. This study highlights the importance of cognitive and behavioral interventions for increasing improvement in these psychosocial domains.

Mixed-metal fretting corrosion of Ti6Al4V and wrought cobalt alloy

Corrosion has been reported at the modular interfaces of total joint replacement implants, but with conflicting theories as to the cause of such damage. The modular design itself leaves the interface susceptible to galvanic, crevice, or fretting corrosion, or a combination of the three. The purpose of this study was to quantify the effect of material combination on fretting corrosion of orthopedic alloys. Each test specimen consisted of a two-hole plate with spherical countersinks and two cortical bone screws. The plates and screws were made of either Ti6Al4V or wrought cobalt-chromium-molybdenum (CCM), and were tested in all mixed-metal and similar-alloy combinations. Fretting corrosion experiments were conducted for 14 days in 10% calf serum, according to ASTM F897. Corrosion damage was evaluated by weight-loss measurements, atomic absorption spectrophotometry and scanning electron microscopy analyses. The results indicated that Ti6Al4V suffered relatively severe damage when fretted against itself, as a result of adhesive galling. The extent of titanium damage was reduced considerably, however, when Ti6Al4V was fretted against wrought CCM. In contrast, there was essentially no difference in wrought CCM damage when the alloys was fretted against itself compared to fretting against Ti6Al4V. Finally, in similar-alloy combinations, Ti6Al4V suffered more severe damage than wrought CCM.

Release of hexavalent chromium from corrosion of stainless steel and cobalt-chromium alloys

Experiments were undertaken to determine whether hexavalent chromium was released during corrosion of orthopedic implants. Uptake of chromium (Cr) by cells and separation using amberlite resin were the methods used to determine that hexavalent Cr was present. We used salts of chromium as trivalent chromium (chromic chloride) and hexavalent chromium (potassium dichromate) to verify that the amberlite separation technique separates hexavalent Cr into the upper phase and trivalent Cr into the lower phase. The use of the salts also verified that only the hexavalent Cr became red blood cell-associated and that most of this was intracellular rather than membrane bound. The use of the amberlite separation technique demonstrated that the hexavalent Cr in the red blood cells was rapidly reduced to trivalent Cr. Cellular uptake of chromium was documented in red blood cells following corrosion of stainless-steel and cobalt-chromium implants in vivo, in the red blood cells of patients undergoing total joint revisions, and in fibroblasts subjected to products of fretting corrosion of stainless-steel and cobalt-chromium implants. Thus, corrosion of implants can lead to the release of the biologically active hexavalent chromium into the body. This chromium is rapidly reduced to trivalent chromium in cells.

A community-based, culturally sensitive education and group-support intervention for Mexican Americans with NIDDM: a pilot study of efficacy

The purpose of this study was to determine the feasibility of providing a diabetes patient education and group-support intervention that was directed by a Mexican-American clinical nurse specialist (CNS), dietitian, and community worker; consistent with national standards; and designed for the Mexican-American culture. In a rural Texas-Mexico border community, subjects with diabetes were randomly selected to participate in the intervention, and a family member of each subject participated as a support person. The intervention involved 8 weeks of educational sessions with instruction on nutrition, blood glucose self-monitoring, exercise, and other diabetes self-management topics, and provided group support. Group discussion was facilitated using a series of Spanish-language videotapes that had been developed and previously tested in the target Mexican-American community. Results suggested statistically significant improvements in diabetes knowledge, fasting blood sugar levels, and glycosylated hemoglobin levels. The study documented the feasibility and potential benefits of the intervention.

Withdrawal and dependency symptoms among adolescent alcohol and drug abusers

Due to differences in duration, intensity and topography of alcohol and drug use patterns, the withdrawal and dependency symptoms of adolescent substance abusers may differ from those of adult substance abusers. To explore these potential differences, 166 adolescents recruited from inpatient alcohol and drug treatment programs in the USA were assessed for alcohol and other drug withdrawal and dependency symptoms. Teens were administered the Customary Drinking and Drug Use Record following 2 weeks of abstinence and evaluated for recent (< 3 months) DSM-III-R psychoactive substance withdrawal and dependency symptoms. Adolescents were all multiple substance users with a life-time average of 4.27 drugs used in addition to alcohol. Amphetamines were the most frequently used drug (50% of sample) and the most prevalent withdrawal symptoms were those associated with central stimulant use. However, the number of different withdrawal symptoms (M = 11.27) was greater than expected for uncomplicated stimulant withdrawal or withdrawal from any single substance. On average, participants reported dependency symptoms more than DSM-III-R criteria for the diagnosis of alcohol dependency (M = 3.30), as well as dependency on their two most frequently used drugs. Heavy alcohol and cigarette use were found to exacerbate withdrawal symptoms of other drugs. These findings highlight the importance of assessing adolescent substance abusers for withdrawal from and dependency on multiple substances.

Impaired renal autoregulatory ability in dogs with reduced renal mass

In normal dogs, the renal autoregulatory mechanism limits the effect of changes in renal arterial pressure (RAP) on RBF, renal outer cortical blood flow (OCBF), and GFR by adjusting the vascular tone of the preglomerular arterioles. To determine the extent to which autoregulatory ability was impaired in remnant renal tissue in dogs, the effects of variations in RAP on RBF, OCBF, and GFR were studied after sham-operation (Group 1; N = 5), 3/4 nephrectomy (Group 2; N = 5), or 7/8 nephrectomy (Group 3; N = 5). In Group 1, the RBF, OCBF, and GFR were not significantly affected by variations in RAP between 75 and 125 mm Hg, indicating intact renal autoregulatory ability. In contrast, both groups of partially nephrectomized dogs exhibited a loss of renal autoregulatory ability below 100 mm Hg (P < 0.05). As RAP rose above 100 mm Hg, dogs with 7/8 nephrectomy exhibited a greater increase than control dogs in RBF (0.586 +/- 0.211 versus -0.080 +/- 0.030 percent change in RBF/mm Hg change in RAP; P < 0.05), OCBF (0.408 +/- 0.157 versus -0.059 +/- 0.054 percent change in RBF/mm Hg change in RAP; P < 0.05), and GFR (0.784 +/- 0.230 versus 0.134 +/- 0.049 percent change in RBF/mm Hg change in RAP; P < 0.05). The ability of the renal vasculature to maintain renal function stable above 100 mm Hg was intermediate in Group 2 and not significantly different from corresponding values for Group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinicopathologic effects of a 21-aminosteroid compound (U74389G) and high-dose methylprednisolone on spinal cord function after simulated spinal cord trauma

A model simulating acute-compressive spinal cord trauma at the second lumbar spinal cord segment (100 g, 300 seconds) was used to evaluate the efficacy of a vehicle control, methylprednisolone sodium succinate (MPSS), and a 21-aminosteroid compound (U74389G). Dogs were allocated into one of five treatment groups (A to E) using ultrasonographic determination of spinal cord diameters to ensure even distribution of spinal cord diameters among the treatment groups. Initial dosages of the vehicle control (A), methylprednisolone (30 mg/kg of body weight) (B), or U74389G (30 mg/kg, 3 mg/kg, or 10 mg/kg of body weight) (C, D, or E, respectively) were administered intravenously 30 minutes after trauma. Dosages were reduced by one-half for 2 and 6 hour treatments. Then every 4 hours for 42 hours, dosages were reduced one-third and one-sixth from the original dose of methylprednisolone and U74389G, respectively. Neurological examinations were performed daily for 21 days. Histopathological examination of the traumatized spinal cord showed malacic and degenerative lesions. Although significant differences in some portions of the neurological and histopathologic examinations were observed, clinical efficacy for MPSS and U74389G could not be established in this model.