Biomedical subjects

P J Armstrong

Publications and source records attributed to P J Armstrong.

At least 19 recordsLinked to original sources

PubMed1997

Cell-mediated immune responses to liver membrane protein in canine chronic hepatitis.

Peripheral blood mononuclear cells from dogs with chronic inflammatory liver disease and dogs with noninflammatory liver diseases were evaluated for proliferative responses to pokeweed mitogen and canine liver membrane protein. Dogs with chronic hepatitis were selected based on histopathological evidence of periportal lymphocytic infiltrates with or without neutrophilic infiltrates, fibrosis and necrosis. Incorporation of tritiated thymidine was assessed 72 hours after addition of liver membrane protein or pokeweed mitogen. Peripheral blood mononuclear cell proliferation in response to liver membrane protein was significantly higher in chronic hepatitis dogs compared to control dogs. Eight of 12 dogs with chronic hepatitis and 2 of 7 dogs with noninflammatory liver disease had proliferative responses to liver membrane protein greater than 2 standard deviations above the mean of the control group. These data support the hypothesis that immune-mediated processes are involved in canine chronic hepatitis, but did not determine whether this is a primary disorder or occurred secondary to liver destruction.

Animals↗

PubMed1997

Inflammatory liver disease.

The histopathologic and clinical features of feline inflammatory liver disease are incompletely under-stood. Results of recent studies indicate that feline inflammatory liver diseases can be classified as acute (suppurative) and chronic (nonsuppurative) cholangiohepatitis and lymphocytic portal hepatitis. Histopathologic features of cholangiohepatitis include infiltration of neutrophils into walls and lumens of bile ducts and portal areas, periportal necrosis, and variable degrees of fibrosis and bile duct hyperplasia. Lymphocytic portal hepatitis is characterized by increased numbers of lymphocytes and plasma cells in portal areas, bile duct hyperplasia, and fibrosis. Liver biopsy is needed to establish a definitive diagnosis but trends in clinical laboratory test results may be helpful in establishing a tentative diagnosis. Specific treatment for cholangiohepatitis include antibiotic therapy. Corticosteroids have been recommended for treatment of lymphocytic portal hepatitis.

Animals↗

PubMed1996

Effect of ovariohysterectomy on maintenance energy requirement in cats.

OBJECTIVE: To determine whether maintenance energy requirement (MER) to maintain stable body weight (BW) is substantially lower for spayed female cats than for sexually intact female cats and to assess whether an equation commonly used to estimate MER would accurately predict caloric need in spayed cats. DESIGN: Prospective study. ANIMALS: 10 spayed and 5 sham-operated young adult female cats. PROCEDURE: During an acclimatization period, initial daily food allowance was determined by estimating MER as 1.4 x (30 x BW + 70), then adjusted weekly to maintain BW within 200 g of baseline. Ovariohysterectomy (OHE) or sham laparotomy was performed at week 7, and the study was continued for 15 additional weeks (period 1). To correct for a presumptive effect of continued musculoskeletal growth that resulted in some cats becoming unacceptably thin during period 1, the study was repeated over an additional 10 weeks (period 2), using a new estimate of MER calculated from BW measured after reestablishing normal body condition. RESULTS: Substantial restriction in food allowance was necessary to prevent BW gain in the OHE group during both periods. Caloric intake of spayed cats in dietary balance was significantly lower than that of control cats at the end of each study period. Sexually intact cats appeared to self-regulate food intake, whereas spayed cats tended to eat all food available to them. Significant differences were not detected between OHE and control groups in observations of physical activity before or after surgery. The equation used to predict caloric needs overestimated the apparent MER for spayed and sexually intact cats. CLINICAL IMPLICATIONS: Ad libitum feeding of spayed cats may be inadvisable, and careful monitoring of food allowance, relative to body condition, is suggested to prevent excessive weight gain.

Animal Feed↗

PubMed1996

Relationship between inflammatory hepatic disease and inflammatory bowel disease, pancreatitis, and nephritis in cats.

OBJECTIVE: To determine whether cats with inflammatory hepatic disease had concurrent inflammatory bowel disease (IBD), pancreatitis, or chronic interstitial nephritis. DESIGN: Prospective case series. SAMPLE POPULATION: 78 tissue sections of liver, intestine, pancreas, and kidney from cats that had previous necropsy examinations at the teaching hospital. PROCEDURE: We reviewed histologic sections of liver, intestine, pancreas, and kidney from cats that had previous necropsy examinations and determined the prevalence of lymphocytic portal hepatitis, cholangiohepatitis, IBD, pancreatitis, and chronic interstitial nephritis, and the relationship among them. RESULTS: 36 cats had lymphocytic portal hepatitis, 18 had cholangiohepatitis, and 24 did not have inflammatory hepatic disease. The prevalence of IBD (10/36; 28%) and pancreatitis (5/36; 14%) in cats with lymphocytic portal hepatitis was not significantly different from cats without inflammatory hepatic disease. The prevalence of IBD (15/18; 83%) and pancreatitis (9/18; 50%) was greater (P < 0.05) for cats with cholangiohepatitis, compared with cats without inflammatory hepatic disease. Thirty-nine percent of cats (7/18) with cholangiohepatitis had IBD and pancreatitis. Evidence of IBD in association with cholangiohepatitis was characterized by infiltration of lymphocytes and plasma cells into the lamina propria; however, neutrophilic infiltrates also were found in 6 of 15 (40%) cats with cholangiohepatitis. Pancreatitis was mild in all cats. CLINICAL IMPLICATIONS: Cats with a diagnosis of cholangiohepatitis should be evaluated for IBD and pancreatitis.

Age Distribution↗

PubMed1996

Geographic, clinical, serologic, and molecular evidence of granulocytic ehrlichiosis, a likely zoonotic disease, in Minnesota and Wisconsin dogs.

Seventeen Minnesota and Wisconsin dogs with granulocytic ehrlichosis were studied. The diagnoses were made by finding ehrlichia morulae in peripheral blood neutrophils. Eight dogs were studied retrospectively, and nine dogs were studied prospectively. The medical records of all dogs were reviewed. Eighty-eight percent of the dogs were purebred and 76% were spayed females. The median age was 8 years. Sixty-five percent of the cases were diagnosed in October and November. Fever and lethargy were the most common clinical signs. The most frequent laboratory findings were lymphopenia, thrombocytopenia, elevated activities of serum alkaline phosphatase and amylase, and hypoalbuminemia. No dogs seroreacted to Ehrlichia canis or Ehrlichia chaffeensis antigens, which are cross-reactive. Seventy-five percent of the dogs tested during the acute phase of disease and 100% of the dogs tested during convalescence were seropositive for E. equi antigens. Granulocytic ehrlichial 16S rRNA gene DNAs from six dogs were amplified by PCR. Sequence analysis of a 919-bp sequence of the ehrlichial 16S rRNA gene amplified by PCR from the blood of two dogs revealed the agent to be identical to the agent of human granulocytic ehrlichiosis in Minnesota and Wisconsin and to be very similar to E. equi and Ehrlichia phagocytophila and less similar to E. canis, Ehrlichia ewingii, and E. chaffeensis. The geographic, clinical, serologic, and molecular evidence indicates that granulocytic ehrlichiosis in Minnesota and Wisconsin dogs is not caused by E. ewingii, but suggests that it is a zoonotic disease caused by an agent closely related to E. equi and that dogs likely contribute to the enzootic cycle and human infection.

Animals↗

PubMed1996

Histopathologic evaluation of feline inflammatory liver disease.

To better define the histopathologic features of feline inflammatory liver disease, we studied feline liver biopsies evaluated at the University of Minnesota Veterinary Teaching Hospital over a 10-year period. Of 175 liver sections examined, 45 had portal inflammatory infiltrates. Of these, 60% had infiltrates consisting of lymphocytes and plasma cells, 24% had infiltrates consisting of neutrophils, and 16% had mixed infiltrates consisting of neutrophils, lymphocytes, and plasma cells. Lymphocytic-plasmacytic portal infiltrates were characterized by various degrees of bile duct proliferation and fibrosis without evidence of bile duct infiltration or periportal necrosis. Sections with portal neutrophilic infiltrates were characterized by bile duct infiltration, bile duct epithelial degeneration, periportal necrosis, and infiltration of neutrophils into adjacent lobules. We propose that hepatitis characterized by portal lymphocyte and plasma cell infiltration be termed lymphocytic portal hepatitis and that hepatitis characterized by cholangitis and portal neutrophilic infiltrates with or without lymphocytes and plasma cells be termed cholangiohepatitis.

Animals↗

PubMed1995

Effects of nitrous oxide on psychological performance. A dose-response study using inhalation of concentrations up to 15%.

In this six-period randomised double-blind study, 12 healthy volunteers inhaled mixtures of nitrous oxide at concentrations of 0% (placebo); 3%, 5%, 7%, 10%, and 15% in oxygen. Each concentration was inhaled for 55 min, each period being on a separate day. The order of treatments was randomised using a Latin-Square design. The effects of nitrous oxide were assessed using a battery of performance tests which included measures of attention, psychomotor function, memory and cognition. Mood was assessed using visual analogue scales. Measures of attention and psychomotor performance showed impairment at 15% nitrous oxide, and subjective measures showed sedation at this dose. The Buschke Selective Reminding Task showed impairment to long-term recall at all doses of nitrous oxide compared to placebo, while short-term recall was impaired only at 15%. These results suggest that consolidation of memory may be particularly sensitive to disruption as a result of CNS depression.

Administration, Inhalation↗

PubMed1994

Disseminated Mycobacterium avium complex infection in three Siamese cats.

Disseminated infection with Mycobacterium avium complex is described in 3 adult Siamese cats. All cats were the result of father-daughter matings. Clinical signs included anorexia, weight loss, and lethargy. Physical examination revealed pale mucous membranes, lymphadenopathy, splenomegaly, and pyrexia. Nonregenerative anemia was detected in all 3 cats, and macrocytosis was observed in 2. An antemortem diagnosis of mycobacterial infection was made on the basis of identification of acid-fast bacilli in tissue aspirates. The cats died or were euthanatized owing to clinical deterioration, despite antibiotic treatment. Necropsy findings included granulomatous lymphadenitis, enterocolitis, pneumonia, cellulitis, myelitis, and hepatitis. Organisms from the Mycobacterium avium complex were identified in bacteriologic cultures of tissue samples.

Animals↗

PubMed1994

The effects of Entonox and epidural analgesia on arterial oxygen saturation of women in labour.

The arterial oxygen saturation of 40 mothers in the first stage of labour was monitored using pulse oximetry. Half the mothers received epidural analgesia and the rest inhaled Entonox for pain relief. Eight mothers in the Entonox group and six in the epidural group had at least one episode of significant hypoxia (saturation < 90%). There was little difference in the number of hypoxic episodes experienced by either group (29 in the Entonox and 21 in the epidural) although their mean duration and severity was greater in the Entonox group. Women in labour who inhale Entonox have an appreciable incidence of arterial desaturation. Epidural analgesia reduces the severity of hypoxic episodes although it does not eliminate them.

Adult↗

PubMed1994

The effect of position and different manoeuvres on internal jugular vein diameter size.

Internal jugular vein (IJV) cannulation is a popular approach for central venous access as it has few complications, of which failure to locate the vein and carotid artery puncture are the most common. A variety of manoeuvres and body positioning has been used to maximise IJV size and thereby increase cannulation success rate and decrease complications. Realtime 2D ultrasound can be used to view neck vascular anatomy in vivo and allow IJV size to be measured. Thirty-five volunteers had the lateral diameter of their IJV measured using the SiteRite ultrasound machine to discover the most effective methods of increasing its diameter. No correlation was found between the IJV lateral diameter and subject height, weight, age or neck circumference. Carotid artery palpation and full neck extension reduced its diameter considerably. Increasing Trendelenberg increased diameter. Abdominal binder and the Valsalva manoeuvre were the most efficient methods of increasing its size.

Abdomen↗

PubMed1993

The 'SiteRite' ultrasound machine--an aid to internal jugular vein cannulation.

The 'SiteRite' is a portable ultrasound imaging system designed to aid vein location during internal jugular vein cannulation. It was compared to the use of anatomical landmarks for internal jugular vein cannulation. It was easy to use and gave good quality images, increased the speed of cannulation, decreased the number of attempts to locate the internal jugular vein and reduced the failure rate, although it had no effect on the incidence of carotid artery puncture.

Catheterization, Central Venous↗

PubMed1993

Continuous subarachnoid infusion of local anaesthetic.

We observed the sensory, motor and cardiovascular changes occurring during subarachnoid infusion of bupivacaine 0.125% at 15 ml.h-1 in six patients. After 1 h, motor block and lower sensory levels were consistent and predictable but upper sensory levels were variable. There was a moderate decrease in systolic blood pressure. Regular assessments of motor block are more likely to detect accidental subarachnoid infusion than assessments of upper sensory level or measurements of blood pressure.

Aged↗

PubMed1993

Pethidine has a local anaesthetic action on peripheral nerves in vivo. Addition to prilocaine 0.25% for intravenous regional anaesthesia in volunteers.

In a double-blind, randomised study, we have examined the effects of the addition of pethidine 100 mg to 40 ml prilocaine 0.25% for intravenous regional anaesthesia in healthy volunteers. During intravenous regional anaesthesia the hand and forearm are isolated from the rest of the circulation and pethidine interaction with central opiate receptors does not occur. Pethidine increased the speed of onset and extent of sensory and motor block, reduced tourniquet and forearm pain, and subjectively improved the quality of the block. Pethidine has local anaesthetic action on peripheral nerves in vivo.

Adult↗

PubMed1992

Epidemiology of Pseudomonas aeruginosa in an intensive care unit using selective decontamination of the digestive tract.

Selective decontamination of the digestive tract (SDD) aims to reduce the rate of nosocomial infections in critical care patients. Pseudomonas spp. are common nosocomial pathogens and in this study isolates collected from patients and the environment during an SDD trial were examined. The study enrolled 161 SDD cases and 170 controls. Pseudomonads were isolated from 27% of SDD patients and 30% of controls. SDD partially suppressed colonization in the 'gastro-respiratory' mucosae but not in the rectum. A total of 108 isolates of pseudomonads were recovered from the environment. Resistance in rectal isolates was minimal but isolates from 'gastro-respiratory' sites showed increasing aminoglycoside resistance. Eighty-six per cent of aminoglycoside-resistant isolates from both patient groups and environment were pyocine type 1x. Episodes of infection were reduced in the SDD patients (6) compared with the controls (16), aminoglycoside-resistant strains being associated with zero episodes in SDD patients but with five in the control group.

Cross Infection↗

PubMed1991

Effects of i.v. lignocaine on psychological performance and subjective state in healthy volunteers.

In order to assess the effects of different doses of lignocaine on performance, nine healthy volunteers aged 21-34 yr received i.v. infusions of saline, low and high dose lignocaine (mean plasma concentrations 0.92 and 1.78 micrograms ml-1, respectively) in a double-blind randomized order. The Digit-Symbol Substitution Test (DSST) and Visual Analogue Scales (VAS) were performed repeatedly and a battery of performance tests once. The median (lower, upper quartile) number of correct responses for the DSST during the infusion period was: placebo 69 (67, 77); low 74 (71, 80); high 66 (61, 75) (P less than 0.001, General Linear Models; all pairwise comparisons P less than 0.05). None of the measures in the full battery showed any significant changes. VAS showed that subjects felt more interested (P less than 0.05), drowsy (P less than 0.01), dizzy, tense, abnormal, drunk and muzzy (P less than 0.001) with lignocaine than with placebo. These results confirm that lignocaine can produce acute performance effects (both improvements and impairments). Subjects were clearly aware of the presence of lignocaine, suggesting that subjective reports may be a useful indicator of its CNS effects.

Adult↗

PubMed1991

The alkalinisation of bupivacaine for intercostal nerve blockade.

A double-blind randomised study was performed to investigate the effect of pH adjustment of bupivacaine, with adrenaline 1:200,000, on the duration of block and pain relief after intercostal nerve blockade following thoracotomy. One group (n = 10) received bupivacaine with adrenaline 1:200,000 (pH = 4.1) and the other (n = 10) received alkalinised bupivacaine with adrenaline 1:200,000 (pH = 6.9). There was no significant difference in block duration (mean 23.9 and 26.4 hours respectively) visual analogue pain scores or morphine usage. Patients were more likely to have a block during the first 12 hours if they received alkalinised bupivacaine (p less than 0.01, Chi-squared test). A progressive regression of block, not previously described, was observed, explicable by means of spread of local anaesthesia to adjacent intercostal nerves. Alkalinisation of bupivacaine with adrenaline for intercostal nerve blockade has little clinical benefit.

Bupivacaine↗

PubMed1990

An epizootic of peroneal and tibial neuropathy in Walker Hound pups.

Early in life, Walker Hound pups from several litters, later determined to have peroneal and tibial neuropathy, had been given supplements of either evaporated milk and corn syrup mixed with well water or powdered bitch milk formula mixed with well water. Other pups not given supplements were not affected. Pelvic limb monoparesis, areflexia, analgesia, and muscular atrophy developed by 2 weeks of age. Abnormalities detected by light and electron microscopy included scattered swollen axons containing increased organelles and whorled neurofilaments. The clear association between clinical signs of disease and dietary supplementation of pups among healthy dogs in a kennel, as well as lack of an obvious pattern of inheritance, suggested an environmentally acquired toxin, specifically the well water. Attempts to reproduce neuropathy in a litter of Beagle pups 2 years after initial evaluation of the disease syndrome were unsuccessful. Atomic absorption studies performed on the well water to detect heavy metals did not reveal toxic concentrations. Toxins that may have been responsible for the neuropathy in these pups were not identified.

Animals↗

PubMed1990

Choice of incision and pain following gallbladder surgery.

A prospective randomized trial compared pain in the first 24 h after gallbladder surgery via an upper midline or a transverse incision. Pain was measured by the patients' self-administered consumption of pethidine, degree of postoperative respiratory impairment and a visual analogue pain scale. The upper midline incision group self-administered significantly more pethidine than the transverse incision group (P less than 0.001), but there was no difference between the groups in respiratory function or visual analogue pain scale results 24 h after operation. Length of hospital stay was not different. An upper midline incision is more painful than a transverse incision in the first 24 h following gallbladder surgery.

Female↗