Significant changes in epidermal Langerhans cells of guinea-pigs infested with ticks (Dermacentor andersoni)

Resistance to tick feeding has previously been shown to be an acquired, immunologically mediated phenomenon in guinea-pigs, associated with cutaneous basophil hypersensitivity to tick antigens. In this study, Langerhans cells (LC) in the epidermis of guinea-pigs were monitored during tick infestations of susceptible and resistant animals. A specific adenosine triphosphatase (ATPase) staining technique was used to identify epidermal LC. The numbers of LC decreased significantly around the sites of tick attachment during primary infestations. Early in the secondary infestations, increases in numbers of LC were observed in the epidermis surrounding tick mouth-parts. These changes in LC populations resemble those previously described in contact dermatitis reactions of guinea-pigs.

Effects of ultraviolet irradiation on the acquisition and expression of tick resistance in guinea-pigs

In guinea-pigs it has been shown that resistance to ticks is an acquired, immunologically mediated phenomenon. It has been suggested recently that epidermal Langerhans cells (LC) may play roles in the mechanisms of resistance to ticks. The ATPase-positive epidermal LC of guinea-pigs have been shown to be depleted for a period of several days following u.v. irradiations. In this study, u.v. treatment of guinea-pigs' ears before primary tick infestations resulted in a significant reduction of acquired resistance to ticks. When u.v. treatments were applied to resistant animals prior to the challenge infestations, a marked reduction in expression of resistance to ticks was demonstrated. These results can be interpreted to imply that functional LC in the epidermis are required for both the normal acquisition and the expression of the guinea-pig's immune responses to D. andersoni infestations.

Effects of ultraviolet irradiation on epidermal Langerhans cells in guinea-pigs

There is good evidence to suggest that u.v. irradiation (UVB) of the skin causes a reduction in the numbers of normal epidermal Langerhans cells (LC) in man and mouse. Little information is available on the effects of u.v. radiation on LC in guinea-pig skin. In this study, different dosages of UVB and UVC were applied to the ear skin of guinea-pigs. UVC irradiations were found more effective than UVB in causing depletions of ATPase-positive epidermal LC. Highly significant depletions, lasting 6 days after irradiation, were produced with little evidence of significant inflammatory reactions occurring in the epidermis.

Responses to submaximal treadmill exercise and training in the horse: changes in haematology, arterial blood gas and acid base measurements, plasma biochemical values and heart rate

Four standardbred horses with subcutaneously relocated carotid arteries were given a seven week training programme of treadmill exercise at a gradient of 19 per cent in order to assess if there were any effects of exercise and training on haematology, arterial blood gas and acid base measurements, plasma biochemistry and heart rate. The exercise consisted of one minute walking at 110 metres/minute followed by five minutes trotting at 200 metres/minute, twice daily in the first week. The period of trotting exercise was increased by one minute per week so that by the seventh week the horses were being given 12 minutes trotting twice daily. Before training commenced venous blood samples, for complete blood counts and plasma biochemistry, and arterial samples, for blood gas, acid base and lactate measurements, were taken at rest, after five minutes and 15 minutes of treadmill exercise (200 metres/minute) and 30 minutes and 60 minutes after completing the exercise. Heart rate was measured by telemetric electrocardiogram at similar intervals. This exercise test and blood collection were repeated after one, three, five and seven weeks of training. The only significant changes were a decrease in exercise lactate with training, increases in exercise and recovery total protein. The haematological response to treadmill exercise included an increase in certain red cell parametes and a leucocytosis which was caused by both a neutrophilia and a lymphocytosis. These effects had largely disappeared by 30 minutes after exercise and all values had returned to resting values by one hour after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Gouty involvement of a flexor tendon in the hand

Gouty tenosynovitis is a well-recognized entity. However, its presentation as a localized mass in the palm is unusual and often not considered in the differential diagnosis. We report a case in which a localized deposit of urate crystals in a flexor tendon presented as a discrete palmar mass.

Effects of clenbuterol hydrochloride on certain respiratory and cardiovascular parameters in horses performing treadmill exercise

Five standardbred geldings received intravenous clenbuterol hydrochloride and saline in a crossover experiment to evaluate the effects of clenbuterol on certain cardiorespiratory parameters during and after treadmill exercise. The exercise test consisted of four steps. Step 1 at a speed of 76 m per minute, step 2 at 129 m per minute, step 3 at 190 m per minute and step 4 at 236 m per minute. The duration of each step was two minutes, except step 4 which was four minutes. The treadmill was set at a grade of 19 per cent. Before exercise, 30 minutes after clenbuterol or saline administration, arterial and mixed venous blood gases, mean arterial pressure, mean pulmonary artery pressure, telemetric electrocardiogram and respiratory rate were measured. The measurements were repeated immediately before completion of step 2, step 4 and after one minute, 10 minutes and 30 minutes of recovery from exercise. After clenbuterol administration there was a transient fall in mean arterial pressure, which had returned to control values by 90 seconds. There was no change in mean pulmonary artery pressure. During exercise the heart rate was significantly higher at the end of steps 1 and 4 and after 10 minutes recovery when horses given clenbuterol were compared with those given saline. No adverse effects on the electrocardiogram were demonstrated. Effects of clenbuterol on blood gases included an increase in PaO2 and decrease in PaCO2 one minute after exercise, when compared to saline. It was concluded from the parameters examined that there was no evidence that clenbuterol had any significant untoward effect on the circulatory system of exercising horses.

Nosocomial infections due to Pseudomonas aeruginosa: review of recent trends

The role of Pseudomonas aeruginosa in nosocomial infections occurring since 1975 is reviewed. Data from the National Nosocomial Infections Study conducted by the Centers for Disease Control, from individual medical centers, and from the literature were used to compare the relative frequency of occurrence of nosocomial infection caused by P. aeruginosa with that of infection caused by other gram-negative bacilli. The relative frequency of P. aeruginosa as a nosocomial pathogen has increased, although wide variations are seen among individual medical centers. P. aeruginosa continues to be a major pathogen among patients with immunosuppression, cystic fibrosis, malignancy, and trauma. While Staphylococcus aureus has become the predominant pathogen in some large burn centers, P. aeruginosa is the most important gram-negative pathogen. Periodic review of the epidemiology of P. aeruginosa infection is warranted in view of the changing incidence of infection caused by this organism.

Simplified technique for histochemical determination of three fiber types in equine skeletal muscle

For determination of 3 muscle fiber types in equine skeletal muscle, a comparison of 2 preincubation buffers, each followed by myosin adenosine triphosphatase staining, was made. Serial sections of the muscle samples (n = 75) were preincubated in an acid buffer (pH 4.6) or a formaldehyde-glycine buffer (pH 7.25) and then were stained for myosin adenosine triphosphatase. Differentiation of muscle fibers into type I, IIA, and IIB was identical with both techniques; however, in the samples prepared at pH 4.6, type I fibers were black; type IIA, light gray; and type IIB, dark gray. In the samples prepared at pH 7.25, types I, IIA, and IIB fibers were white, light gray, and dark gray respectively. The formaldehyde-glycine preincubation buffer (at pH 7.25) gave more consistent results, was easier to prepare, and retained cytoarchitecture better, compared with the samples prepared at pH 4.6.

Studies on isoxsuprine hydrochloride for the treatment of navicular disease

A peripheral vasodilating agent, isoxsuprine hydrochloride, administered as an oral paste, was evaluated to determine its efficacy for the treatment of navicular disease. In a clinical trial, 13 horses with navicular disease were treated at a dose rate of 0.6 mg/kg body weight (bwt) twice daily for periods of six to 14 weeks. Twelve of the horses became completely sound while being treated, although two required a 50 per cent increase in dose. Nine of the horses have remained sound two to 10 months after ceasing therapy. In a controlled randomised double blind clinical trial, 16 horses with navicular disease were assigned to treatment with either a placebo paste or isoxsuprine paste for three weeks and then re-examined. All the horses treated with isoxsuprine showed improvement in gait, with seven of eight horses becoming sound, whereas only two horses treated with a placebo paste showed slight improvement. This difference in response was highly significant (P less than 0.001). To evaluate any physiological and biochemical effects of isoxsuprine, it was administered to five Standardbred geldings at dose rates of 0.6 mg/kg bwt and 1.2 mg/kg bwt. Complete blood counts, routine plasma biochemical parameters, cardinal signs and blood pressure measurements were performed up to 24 h after a single dose. No significant change in any of these parameters was found. To assess the peripheral vasodilatory action of isoxsuprine, infra-red thermography of the lower limb was performed before and up to 8 h after administration to horses. This revealed a significant increase in distal limb temperature which occurred from 90 to 480 mins after isoxsuprine administration. The maximum mean increase in distal limb temperature was 3.1 degrees C and this occurred 4 h after administration of the drug.

In vitro feeding of Dermacentor andersoni (Stiles): effects of histamine and other mediators

Female Dermacentor andersoni were induced to feed on defibrinated bovine blood through fixed mouse skin membranes. Their feeding behaviour was recorded electronically, the tick being incorporated into the circuit and acting as a variable resistor during the periods of sucking, salivation and rest. Recordings of the feeding behaviour of these ticks were similar to those of ticks feeding on rabbits. Known concentrations of histamine, serotonin, dopamine, prostaglandin E1 and prostaglandin F2a were added singly or in combination to the feeding medium of ticks attached to the mouse skin membrane. Addition of both histamine and serotonin was followed by a significant reduction in the amplitude or recordings associated with sucking and salivation. The concentration of mediators producing this effect was less than 10 mM, a concentration comparable to that of histamine found locally in the skin of tick-resistant guinea-pigs. Comparisons are made between the effects produced by these mediators in ticks and the effects of serotonin and other amines known to produce modulation of complex behaviour patterns in other invertebrates.

Polymicrobial bacteremia associated with lipid emulsion in a neonatal intensive care unit

Polymicrobial bacteremia developed in 5 of 20 infants in a neonatal intensive care unit during a 48-hour period; 2 infants died. Klebsiella pneumoniae serotypes 21 and 24 and Enterobacter cloacae were isolated from four infants, and K. pneumoniae serotype 24 and E. cloacae were isolated from the other infant. Case-control studies revealed an association between receipt of lipid emulsion on one day and the subsequent development of bacteremia (P = 0.0005). Epidemiologic evidence suggested that extrinsic contamination of the lipid emulsion bottles had occurred when the hands of a nurse became transiently colonized with these organisms while she was caring for an infant colonized with K. pneumoniae and E. cloacae. Repeated entry of the lipid emulsion bottle, which was used as a multidose medication, probably resulted in contamination. No further cases occurred after lipid emulsion administration practices were changed. We recommend that, except in a pharmacy where conditions for unit dose distribution exist, lipid emulsion should not be used as a multiple dose medication because repeated entry of the bottles increases the risk of contamination. Furthermore lipid emulsion from one container should be administered to only one infant.

Campylobacter enteritis in the United States. A multicenter study

During a 15-month study, 8097 fecal specimens submitted to clinical microbiology laboratories at eight hospitals in different parts of the United States were examined. Campylobacter jejuni was isolated from 4.6%, Salmonella from 2.3%, and Shigella from 1.0%. Isolation rates for each pathogen were highest from stool specimens that were watery, bloody, or contained leukocytes. The peak isolation rate for C. jejuni was in persons ages 10 to 29 years; for Salmonella, in children younger than age 10 years; and for Shigella, in children ages 5 to 9 years. The clinical features of the three infections were nearly identical. In contrast, abdominal pain, bloody diarrhea, fever, tenesmus, and abnormal sigmoidoscopy findings were present significantly more often in patients infected with C. jejuni than in a control group of patients with diarrhea. Of patients with leukocytes in their stools and a history of fever, 45.9% were infected with one of the three pathogens. Use of laboratory and clinical findings defined groups with high or low risk of these three infections but could not accurately predict isolation. Fecal cultures had the highest yields when obtained from patients within 7 days from the onset of symptoms.

The use of predictive modeling to test nursing practice outcomes

A middle range, multivariate practice model was constructed to test the impact of a perioperative teaching program on multiple patient outcomes: coping, anxiety, recovery pattern, pain, and patient satisfaction. In addition, the influence of such a program on nursing staff was examined. A quasi-experimental, causal modeling approach was used. The operative trajectory of 88 patients and their operating room nursing staff was traced from two pre-operative points through the intra-operative stage to two points post-operatively. The experimental patients (n = 54) evidenced higher satisfaction with their care, a tendency to experience less post-operative vomiting, but also tended to recover more slowly and cope less well than the control patients (n = 34). Multiple regression analysis of the practice model suggested the perioperative teaching program affected patient outcomes, indirectly, through the functioning of the staff nurses intra-operatively.

Red cell ouabain-sensitive Na+-K+-adenosine triphosphatase: a state marker in affective disorder inversely related to plasma cortisol

Ouabain-sensitive Na+-K+-stimulated ATPase was measured in red cell membranes using a spectrophotometric assay. The mean enzyme level in patients in the depressed state (1.2 nM/mg protein per min +/- 0.18 SEM) was lower lower than that in well-state patients (2.0 +/- 0.26) and hypomanic patients (2.4 +/- 0.31). Lithium treatment itself did not alter ATPase levels. Levels in patients in the well state were not significantly different from controls and thus ATPase does not constitute a "trait" marker for affective illness. Plasma cortisol level was higher in well-state patients (15.9 micrograms/dl +/- 1.46) than in controls (11.5 +/- 0.75). There were no significant differences in cortisol in these single morning samples during different mood states. Cortisol level correlated negatively with ATPase level in the total group of patients (r = 0.42, p less than 0.005), especially in those who were euthymic. These data indicate a relationship between cortisol and ATPase levels in affectively ill patients. Ouabain-sensitive NaK ATPase may be useful as an indicator of state in affective illness; plasma cortisol may be continuously elevated in some individuals with affective disorder.

The emergence of methicillin-resistant Staphylococcus aureus infections in United States hospitals. Possible role of the house staff-patient transfer circuit

Infections with methicillin-resistant strains of Staphylococcus aureus appear to be occurring with increasing frequency in some U.S. hospitals about a decade after a similar increase in Britain and other countries. In the United States, clustered methicillin-resistant S. aureus infections reported in scientific journals and in three hospital surveys have been almost entirely in large, tertiary referral hospitals affiliated with medical schools. Among 63 hospitals regularly reporting infections from 1974 to 1981 in the National Nosocomial Infections Study, the increase in methicillin-resistant S. aureus infections was entirely due to substantial increases in only four hospitals, all of which were large, tertiary referral centers affiliated with medical schools. The predominance of methicillin-resistant S. aureus infections in these large hospitals may be due to the large numbers of patients at high risk of infection and to the interhospital spread of the organism by the transfer of infected patients and house staff from similar hospitals or from nursing homes.

Nosocomial hepatitis A transmission by an adult patient with diarrhea

Hepatitis A occurred in five registered nurses, a licensed practical nurse, and a recently discharged patient at a community hospital; one of these seven was asymptomatic. All had been exposed to a woman with confirmed hepatitis A who had undergone elective cholecystectomy and who had had vomiting, diarrhea, and fecal incontinence during the eight days before onset of jaundice. Of the 107 hospital workers identified as having at least some exposure to the source patient, 58 (54.2 percent) had no pre-existing antibody to hepatitis A virus (anti-HAV) and were considered susceptible. Six persons, including the five clinically ill registered nurses, had IgM-specific anti-HAV. The infection attack rate was 5.6 percent for all exposed hospital workers but 10.3 percent for the 58 who were serosusceptible. Risk of infection was highest for persons with documented or probable contact with the source patient and for registered nurses. Among hospital personnel, the prevalence of anti-HAV increased with age but varied inversely with socioeconomic status. Hospital personnel and patients may be at risk for hepatitis A infection when exposed to patients who are in the prodromal stage of hepatitis A. Vomiting, diarrhea, and fecal incontinence may increase the risk of transmission.

Alkaline phosphatase-positive Langerhans cells in the epidermis of cattle

Dendritic alkaline phosphatase-positive cells in the epidermis of cattle were studied. By light microscopy they were shown to occur in basal and suprabasal positions in the epidermis, with their dendrites reaching into outer layers of the stratum spinosum. They were also found in the external root sheaths of hair follicles. In separated epidermal sheets from ears of cattle these cells were found to be uniformly distributed with an average concentration of approximately 1,600 cells/mm2. Langerhans cells were identified in the epidermis by the presence of dendritic cells of Langerhans cell granules, a lobated nucleus and clear cytoplasm and the absence of desmosomes, tonofilaments, premelanosomes, and melanosomes. Alkaline phosphatase activity was associated with the plasmalemma of such cells and occasionally with cytoplasmic inclusions which may have been Langerhans cell granules. Enzyme activity was not associated with melanocytes or keratinocytes. It is confirmed that alkaline phosphatase activity is a feature of Langerhans cells, and possibly "indeterminate" cells in the normal epidermis of cattle.

Growth of nosocomial pathogens in multiple-dose parenteral medication vials

The extent to which microbial contamination of medications dispensed in multiple-dose vials might serve as a source of infection to patients has not been fully investigated. To characterize the effects of microbial contamination, we studied the growth-supporting properties of eight medications dispensed in multiple-dose vials. Two medications, procainamide and methohexital, demonstrated no survival of any microbes 24 h after inoculation. Succinylcholine chloride, regular insulin, potassium chloride, heparin, and thiopental slowly killed or allowed limited survival of several of the microorganisms used as contaminants. Lidocaine allowed survival or proliferation of several microbial strains suspended in 0.25% peptone water in saline, but slowly killed all strains except Pseudomonas cepacia suspended in 0.9% saline. Endotoxin, measured by the Limulus amebocyte lysate assay, was found in the two medications tested, lidocaine contaminated with Pseudomonas cepacia and insulin contaminated with enterococci. Inadvertent microbial contamination of at least some parenteral medications in multiple-dose vials may result in the exposure of patients to viable organisms. The potential, however, for medications such as lidocaine to support growth of organisms under selected circumstances should be noted by those responsible for preparing and administering these drugs. The potential hazard to patients from endotoxin in contaminated medications under these circumstances has not been assessed. Additional studies of this type should be pursued to provide more complete information about the risk of microbial contamination of products for parenteral use.

Identification of an arene oxide metabolite of 2,2',5-5'-tetrachlorobiphenyl by gas chromatography-mass spectroscopy

Tritiated 2,2'5,5'-tetrachlorobiphenyl (3H-TCB) was incubated with phenobarbital(PB)-induced rat liver microsomes in the presence of an epoxide hydrase inhibitor and brominated analog (BrAO) of the expected metabolic intermediate, 2,2',5,5'-tetrachlorobiphenyl-3,4-oxide (TCBAO). A putative arene oxide intermediate (3H-AO), which was radiolabeled, was separated from 3H-TCB and BrAO by column chromatography, high pressure liquid chromatography (HPLC) and thin-layer chromatography (TLC), and was analyzed for TCBAO by methods that were independent of radiometric techniques. The retention times (Rt's) of TCBAO and 3H-AO on two gas chromatography (GC) columns were the same, both before and after acid catalyzed rearrangement. 3H-AO was further characterized by rearrangement to a mixture of 3- and 4-hydroxy-TCB that was identified by gas chromatography-mass spectroscopy (GC-MS). The rate of TCB metabolism and the production of 3H-AO by liver microsomes from a PB-induced, adult male rhesus monkey was less than that observed with rat microsomes. The 3H-AO from the monkey was also characterized as TCBAO by rearrangement to the characteristic TCB phenols that were analyzed by GC-MS using selective ion monitoring. This study is the first in which an arene oxide of a polychlorinated biphenyl (PCB) was actually isolated as a mammalian metabolite and subjected to direct chemical analysis.