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Biomedical subjects

G A Anderson

Publications and source records attributed to G A Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1995

Bio-affinity characterization mass spectrometry.

A new approach, bio-affinity characterization mass spectrometry (BACMS), aimed at providing a more rapid, sensitive and potentially more flexible alternative to techniques presently employed for the characterization of noncovalent interactions in mixtures, such as would be encountered in combinatorial chemistry, in presented. BACMS avoids some of the difficulties and potential artifacts associated with affinity chromatography since the noncovalent associations occur in solution; thus, BACMS avoids the requirement of solid support media and the development of non-interfering linker species. This paper describes the conceptual basis for the methodology and its potential use in applications which include the screening of high affinity ligands in support of new drug development. BACMS exploits new Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry technologies which, when coupled to electrospray ionization (ESI), allow the investigation of specific noncovalent complexes formed in solution. BACMS utilizes the well-known attributes of FTICR, such as the high resolution mass analysis and (MS)n (n > or = 2) capabilities; however, it is even more directly a result of recently developed techniques involving quadrupolar excitation, such as selected-ion accumulation. These tools are demonstrated and the results illustrate the extraordinary sensitivity achievable (solution concentration of 1 x 10-9 M without the use of separations prior to ESI). Thus, the new capabilities demonstrated here, in conjunction with ESI, will be useful for the investigation of very low relative concentration noncovalent association directly from solution, and promote a faster alternative for combinatorial mixture screening and analysis.

Animals↗
PubMed1995

Sclerosing Sertoli cell tumor of the testis: a distinct histological subtype.

PURPOSE: A case of sclerosing Sertoli cell tumor of the testis is reported. The histological and clinical features are compared to those of other Sertoli cell tumor subtypes. MATERIALS AND METHODS: The current urological and pathological literature was reviewed. RESULTS: The tumor was identified incidentally in a 35-year-old white man. Pathological examination was performed and the patient was well at 9 months. CONCLUSIONS: Sertoli cell tumors are heterogeneous and not accurately considered a uniform entity. The currently recognized variants differ in apparent malignant potential as well as the association with disease processes in other unrelated organ systems.

Adult↗
PubMed1994

Acute exercise and cardiovascular responses to stress in rats.

The purpose of this study was to determine if acute exercise (EX) reduces the cardiovascular response to air jet stress (AJS) in rats. Male Sprague-Dawley rats (n = 11) were instrumented with Doppler flow probes and a carotid arterial catheter to determine mean arterial pressure (MAP), heart rate (HR), mesenteric blood flow (MesBF), and iliac blood flow (IliBF). Rats participated in two trials (random order, separated by 48 h): 1) nonexercise (NONEX; 90-min rest on treadmill, 20-min restraint, and 20-min AJS), and 2) exercise (EX; 60-min rest on treadmill, 30-min EX at 20 m/min, 20-min restraint, and 20-min AJS). Increases in MAP (EX = 11 +/- 2%; NONEX = 21 +/- 2%) and HR (EX = 22 +/- 4%; NONEX = 33 +/- 3%) in response to the AJS protocol (restraint+AJS) were significantly less after EX compared to NONEX. Furthermore, decreases in MesBF (EX = -12 +/- 7%; NONEX = -29 +/- 8%) and increases in IliBF (EX = 29 +/- 16%; NONEX = 56 +/- 9%) produced by combined restraint+AJS were significantly less after exercise. Interestingly, the effects of exercise were most evident in response to the mild restraint required for AJS. The results suggest that acute EX reduces the cardiovascular responses to an AJS protocol (restraint+AJS) in normotensive rats.

Animals↗
PubMed1994

Diarrhoea in merino ewes during winter: association with trichostrongylid larvae.

A study on 3 farms, each having a preventive strategy for the control of nematode infections, determined the risk factors associated with diarrhoea among Merino ewes in winter. Comparisons were made among groups of mated and unmated ewes with and without treatment with controlled-release capsules containing albendazole. Diarrhoea was assessed from the accumulations of faeces around the breech (dag score) and related to worm egg counts, total worm counts and histopathological findings. The overall prevalence of severe dag in ewes not treated with a capsule was 26% (221/844). In comparison, only 2.7% of treated ewes had severe dag. The adjusted odds ratio on each farm indicated that untreated ewes were between 12 and 16 times more likely to be affected with severe dag than ewes treated with a capsule. The effect of lactation was significant on only one farm whereas initial body weight had no significant effect. There was no significant association between worm egg counts and the occurrence of severe dag. There were significantly more eosinophils in the small intestine of ewes affected with severe dag compared with unaffected ewes. There were no significant differences in mast cell and globule leucocyte numbers between affected and unaffected ewes. This study provides strong evidence that the main cause of diarrhoea among Merino ewes grazing winter and early spring pastures is the ingestion of trichostrongylid larvae even by sheep that have a well-developed protective immune response to these parasites. New strategies for the control of nematode infections are needed to prevent diarrhoea and dag formation in adult sheep.

Animals↗
PubMed1994

Comparison of serum responses in swine after vaccination and challenge exposure with Actinobacillus pleuropneumoniae serotype 1.

Clinical trials have shown that currently available commercial vaccines against porcine pleuropneumonia provide inconsistent, serotype-specific protection from the disease. Recovery from naturally acquired infection, however, provides solid, serotype cross-protective immunity. We examined various serum responses of pigs receiving 1 of 4 commercial vaccines or a cell extract, and compared the serologic responses of these pigs after challenge exposure with virulent Actinobacillus pleuropneumoniae serotype 1. Evaluation of serum included complement-mediated killing, opsonizing capacity, IgG titers to whole organisms, and cytotoxin neutralization titers. Pigs that received the cell extract had fewer clinical signs of pleuropneumonia than pigs in other vaccinated groups, and also were significantly (P < 0.05) better protected from development of lung lesions and death. Such vaccinates were the only pigs that developed significant (P < 0.05) serum antibody titers (ie, protective immune response) to whole-cell antigens and to cytotoxin.

Actinobacillus Infections↗
PubMed1993

Polycystic renal disease.

Renal cystic disease is a relatively common disorder whose development and progression currently appear to be due to an interaction between an abnormal basement membrane matrix, a potentially immature, hyperproliferative epithelium, and an abnormal epithelial secretory apparatus. RCC risk in cystic kidneys is the most controversial sequela of PKD. Currently, RCC risk in ESRD patients appears to be close to that present in the general population and only coincidentally associated with renal cysts. Screening of all ESRD patients for RCC and prophylactic native nephrectomy in dialysis and transplant patients does not seem to be indicated.

Carcinoma, Renal Cell↗
PubMed1993

Cysticercosis of the flexor digitorum profundus muscle producing flexion deformity of the fingers.

Selective flexion deformity of the middle and ring fingers resembling a mild type of Volkmann's contracture resulted from Cysticercus cellulosa infection within the deep flexor muscle of the forearm in a middle-aged woman. Excision of the fibrotic segment of the muscle and tenodesis of all the flexor profundus tendons restored normal range of motion to these fingers. Vascular compromise in addition to the inflammatory response to the infection were considered causes for the deformity. There is no previous report of this kind in the literature.

Adult↗
PubMed1993

The importance of secreted virulence factors in Actinobacillus pleuropneumoniae bacterin preparation: a comparison.

Current bacterins provide only partial protection against morbidity and mortality in swine following infection by Actinobacillus pleuropneumoniae. We compared the efficacy of a cell-free concentrate from mid-log phase growth cultures of Actinobacillus pleuropneumoniae (APP) serotype 1 to four commercial bacterins. This cell-free preparation contained carbohydrate, endotoxin, and protein, and had hemolytic and cytotoxic activity. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis analysis indicated the presence of one major 110,000-molecular-weight protein. This protein band also stained by the periodic acid Schiff method, indicating the presence of carbohydrate. Cell-free concentrates of APP serotypes 5 and 7 had identical profiles following electrophoresis and staining with either Coomassie blue for protein or Schiff reagent for carbohydrate. Lipopolysaccharide profiles for the cell-free concentrates of serotypes 1 and 5 were semi-rough while the LPS profile for serotype 7 was smooth. Five A. pleuropneumoniae-free SPF pigs per group were vaccinated on days 0 and 21 with cell-free concentrate of serotype 1 plus adjuvant, or one of four commercial bacterins according to the manufacturer's directions. Control pigs were vaccinated with PBS mixed with adjuvant. All pigs were challenged intranasally on day 35 with serotype 1 and necropsied on day 50. Protection was greatest in the cell-free concentrate group, as compared with all other groups, in that no deaths occurred, clinical scores were less severe, and percent lung affected was significantly reduced (P < 0.05). In addition, whole-cell ELISA titers were significantly increased (P < 0.05) postvaccination in the cell-free concentrate group, and postvaccination and postchallenge sera neutralized the hemolytic activity of the cell-free concentrate from serotypes 1 and 5 (P < 0.05), as compared with all other groups. No serum neutralization to the hemolysin of serotype 7 was observed. Immunoblot analysis using antisera derived from gnotobiotic pigs indicated that the cell-free vaccine generated a response that was identical to the response observed following live challenge. Similar, but not identical, responses were observed when antisera generated against the bacterins was used. This study indicates that an acellular vaccine containing multiple virulence factors can provide complete protection from mortality and significantly reduced morbidity to homologous challenge.

Actinobacillus Infections↗
PubMed1993

Quantitation of potentially undiagnosed incidental carcinoma of the prostate in patients treated non-surgically for benign prostatic hyperplasia.

Prostatectomy is the standard treatment for benign prostatic hyperplasia (BPH) and non-surgical treatment of prostatism would reduce the detection of Stage A prostate cancer. We wished to identify the number of potentially undiagnosed cancers resulting if non-surgical therapy were used to treat a presenting complaint of BPH. We also sought to identify the age group which would most clearly benefit from treatment of Stage A prostate cancer. Our series of transurethral prostatectomy specimens showed 92/996 patients (9.2%) positive for incidental carcinoma; 26/92 patients (28%) received further treatment and 25 of the 26 patients had Stage A2 disease. After evaluating life-tables and survival data on untreated A2 disease, the population aged < or = 72 years had a relative benefit of treatment ratio > 1.0, i.e. had a greater likelihood of dying from prostate cancer than from natural causes; 17/616 (2.8%) of the population aged < 72 years had their A2 disease treated and would have potentially been denied early cancer treatment if non-surgical management of BPH had been employed. The above figures assume 100% non-surgical treatment of BPH and no screening for prostate cancer pre-treatment. Stage A2 patients in this study demonstrated no significant difference in cause-specific survival rates between treated and untreated study groups (both 0%) or between treated study patients and untreated historical patients. Treated A2 patients demonstrated a significantly lower 5-year progression rate (0 vs 32%) relative to untreated patients reported in the literature, and a trend toward a significantly lower progression rate (0 vs 25%) relative to untreated study patients.

Age Factors↗
PubMed1993

Relationship between milk production and somatic cell count in dairy cows in East Gippsland.

The analysis of records for 75,821 herd tests on 23,700 cows in the Macalister Irrigation District of East Gippsland, using a model that also included stage of lactation, herd and cow effects, found a strong relationship between somatic cell count and milk production. Unit increases in the natural logarithm of the somatic cell count were associated with decreases in production of up to 2.6% in the range 54,598 to 403,429 cells per mL. This is equivalent to a decrease of 1.9% for a doubling of cell count from 100,000 to 200,000 cells per mL. Subclinical mastitis was assessed to be a significant source of loss in milk production in the study area.

Analysis of Variance↗
PubMed1993

Reproductive performance of thoroughbred mares on six commercial stud farms.

The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the first served oestrous cycle (77.8%) than in mares that needed two served oestrous cycles to become pregnant (65.4%). Of all diagnosed pregnancies, 19.5% were not completed. Pregnancy loss was lower (P < 0.05) in maiden (12.4%) than in barren (19.7%) or foaling (20.9%) mares. Twins were diagnosed in 7.8% of all pregnancies. If one conceptus was lost without external interference, 84.1% of pregnancies went to term. If one conceptus was manually crushed, 55.9% of pregnancies were maintained. If prostaglandin was used to terminate twin pregnancies, 60% of mares so treated produced foals the following year.

Age Factors↗
PubMed1992

In vivo measurement of bone quality in the horse: estimates of precision for ultrasound velocity measurement and single photon absorptiometry.

The in vivo precision of ultrasound velocity measurement and single photon absorptiometry for the assessment of equine bone quality is discussed. In vivo precisions for ultrasound velocity measurements were less than 0.5 per cent, whereas cortical cross-sectional area, compact bone density and modulus of elasticity were around 1 per cent, and bone mineral content and density were just over 2 per cent. Except for ultrasound velocity, substantial improvements could be achieved by taking the mean of five readings for each measurement. The long-term precision of the techniques was also high, with all precision values being less than 3 per cent. The possible sources of variation in ultrasound velocity measurements were also investigated. The method for combining ultrasonic and photon absorptiometric data for equine bone quality assessment has been proven to be highly accurate and precise. There appears to be no reason why the same principles cannot be applied with equal success to the noninvasive assessment of bone quality in humans.

Absorptiometry, Photon↗
PubMed1992

Association of virulent and avirulent strains of bluetongue virus serotype 11 with premature births of late-term bovine fetuses.

Two strains of bluetongue virus serotype 11 (BTV 11), UC-2 avirulent and UC-8 neurovirulent in newborn mice, were inoculated into late-term bovine fetuses to investigate whether infection with these two BTV strains in late gestation would produce congenital infection and pathological changes. Fetuses were inoculated by intramuscular injection through the uterine wall at 243 days gestation and recovered after spontaneous delivery. In calves inoculated with UC-8, births occurred 15 to 27 days before expected parturition, resulting in small, weak calves. These calves had a mild encephalitis and were unthrifty at birth. Calves inoculated with UC-2 appeared healthy when born 7 to 11 days prior to expected parturition. No lesions were found in these calves at necropsy. All calves seroconverted by the time of birth. Viraemia was present in the calves inoculated with UC-8 and in one calf inoculated with UC-2. Plasma cortisol concentrations were prematurely elevated, particularly in the calves inoculated with UC-8, indicating that they were stressed by the infection. The elevated cortisol, associated with an active congenital infection caused by bluetongue virus serotype 11 strain UC-8, is capable of causing premature delivery of low birth-weight, weak calves.

Animals↗
PubMed1992

Chromosomal defects in renal cell carcinoma.

Numerous chromosomal defects have been identified in hereditary and sporadic renal cell carcinoma (RCC) tumor cells. Current data indicate that visible, and/or submicroscopic lesions on the 3p are fundamental to RCC development; other chromosomal abnormalities are identified less frequently and may be secondarily involved in RCC production in some cases. Oncogenesis may be initiated via inactivation of suppressor allele pairs, or through activation of oncogenes via translocation to areas of increased gene expression, migration to a chromosomal breakpoint, or gene amplification.

Carcinoma, Renal Cell↗
PubMed1992

Infection of bovine fetuses at 120 days' gestation with virulent and avirulent strains of bluetongue virus serotype 11.

Bluetongue virus infection in sheep and cattle during fetal development causes neuropathology. Two strains of bluetongue virus serotype 11 designated as UC-2 and UC-8 have different virulence patterns in newborn mice. These viruses have distinctly different electropherotype patterns on polyacrylamide gel electrophoresis indicating a genetic difference in these two viruses of the same serotype. Four bovine fetuses each were inoculated intramuscularly with either UC-2 or UC-8, and one fetus was inoculated with placebo. The inoculation was made intramuscularly through the uterine wall at 120 days' gestation, and the bovine fetuses were recovered by cesarean section 12 or 20 days after inoculation. Fetal blood was collected for virus isolation and serology. Virus was reisolated from brain, blood, lung and liver. Both strains, UC-2 and UC-8, cause severe lesions in the 120 day fetuses. The encephalomalacic lesions occurred earlier and were more severe in fetuses inoculated with UC-8 as compared to those inoculated with UC-2. The subtle differences observed in the fetuses inoculated with the two different strains suggest that there is a difference in pathogenic potential of the two viruses. These differences do not appear to be completely dependent upon the host species.

Animals↗
PubMed1992

Opponensplasty by extensor indicis and flexor digitorum superficialis tendon transfer.

From 1977 to 1988, 166 patients with median nerve paralysis of varied aetiology underwent opponensplasty. In 50 of these the extensor indicis was used, and in 116 the flexor digitorum superficialis of the ring finger. An analysis of these hands showed that the EI opponensplasty was best in supple hands and FDS opponensplasty was more suitable for less pliable hands. There were fewer complications seen after FDS opponensplasty if the detachment of the donor tendon was done through a volar oblique incision rather than the conventional lateral incision.

Adolescent↗
PubMed1992

A comparison of the urological complications associated with long-term management of quadriplegics with and without chronic indwelling urinary catheters.

The primary objective of this retrospective study was to compare the incidence of urological complications and renal deterioration in post-traumatic quadriplegic patients managed with or without a chronic indwelling urinary catheter. The charts of 57 consecutive patients who sustained traumatic cervical spinal cord injury between 1970 and 1980 were reviewed. All of the patients received the initial management or rehabilitation therapy at our institution. The unique features of this clinical review are that a large cohort of patients was followed for a minimum of 10 years, none of the 57 consecutive patients was lost to followup and a yearly excretory urogram provided an objective assessment of the renal units. The followup, and mechanism, level and degree of injury for the 32 patients managed with and 25 managed without a catheter were similar. Overall, the incidences of renal and bladder calculi, pyelonephritis, gross hematuria, penile/urethral erosion, urosepsis, urethral stricture, epididymitis and pyonephrosis were not significantly different in the catheterized and noncatheterized groups. The Kaplan-Meier analysis of the most recent excretory urogram demonstrated that the incidence of renal deterioration was also equivalent in the catheterized and noncatheterized groups. Our study suggests that the decision to manage quadriplegics with or without an indwelling catheter should not be based on relative risk of complications or renal deterioration. The decision to avoid an indwelling catheter in these patients should reflect patient comfort, convenience and quality of life.

Adult↗