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Biomedical subjects

M A Scott

Publications and source records attributed to M A Scott.

At least 37 records · Page 2Linked to original sources
PubMed2000

A glimpse at sperm function in vivo: sperm transport and epithelial interaction in the female reproductive tract.

The process of sperm transport in the female reproductive tract is more than simply a migration of spermatozoa from the site of insemination to the site of fertilization. Rather, it is a complex and dynamic continuum that encompasses phases of sperm distribution within the tract, the accumulation of spermatozoa in reservoirs, the modulation of sperm physiology and acquisition of fertilization competence, the ascent of competent spermatozoa to the site of fertilization, and the elimination of the non-fertilizing sperm population. The dynamic interactions that occur between functional spermatozoa and the luminal fluids and epithelial surfaces of the female genital tract during transit and storage enhance sperm survival and regulate sperm function in the female. The universal nature of this interaction highlights it as a key component of the sperm transport process.

Animals↗
PubMed2000

Transfer and motor skill learning in association football.

Transfer of learning involves the influence of previous experiences on the performance or learning of new skills. It is defined as a gain (or loss) in the capability for performance on one task as a result of practice on another. The aim of the study was to examine the degree of transfer between various association football skills. Twenty intermediate male players participated in the study. During pre- and post-training tests, participants juggled a football as many times as possible within 30 s using feet or knees. Further tests required participants to control an approaching football inside a restricted area using the preferred and non-preferred kicking leg. Following performance on the pretest, two matched skill groups were obtained. One group participated in a 4-week training period in which feet-only ball juggling was practised for 10 min daily, while the remaining group acted as a control. Trained participants exhibited superior post-test performance on knee juggling and ball control with preferred and non-preferred leg tasks relative to the control group (p < 0.05). Findings indicate positive transfer of learning from juggling practice with the feet to juggling with the knees and a football control task. Implications for theory and practice are highlighted.

Adult↗
PubMed2000

Primary isolation of Ehrlichia chaffeensis from patients with febrile illnesses: clinical and molecular characteristics.

Ehrlichia chaffeensis was sought among patients with a history of tick exposure and fever, and the accuracy of other diagnostic tests was compared with that of primary isolation. Among the 38 patients enrolled, E. chaffeensis was isolated from the blood of 7 (18%) and from cerebrospinal fluid specimens of 2 of these 7. All 7 patients also were positive by polymerase chain reaction (PCR) of blood, and 6 patients developed diagnostic titers of antibody to E. chaffeensis. The isolates were characterized by molecular analysis of the 16S rRNA gene, the 120-kDa protein gene, and the variable-length PCR target (VLPT) of E. chaffeensis. On the basis of the 120-kDa and VLPT genotypes, the cerebrospinal fluid and blood isolates from the same patients were identical. This study demonstrates that both PCR and culture of blood for E. chaffeensis have high diagnostic yields. More frequent isolation of E. chaffeensis from patients with infection should further our understanding of the pathogenesis of this infection.

Adolescent↗
PubMed2000

The pathologic spectrum of gastrointestinal and hepatic histoplasmosis.

We characterized the pathologic spectrum of lesions in gastrointestinal and hepatic histoplasmosis by studying cases of disseminated disease in immunocompromised and immunocompetent patients from endemic and nonendemic areas. We evaluated 56 specimens from 52 patients with H&E and silver stains. Of these patients, 43% presented with gastrointestinal rather than pulmonary symptoms. Thirty-one percent had gastrointestinal lesions, 10% had liver lesions, and 43% had both. Gross gastrointestinal features included ulcers (49% of patients), nodules (21%), hemorrhage (13%), obstructive masses (6%) and normal mucosa (23%). Microscopic gastrointestinal findings included diffuse lymphohistiocytic infiltration (83%), ulceration (45%), lymphohistiocytic nodules (25%), or minimal inflammatory reaction (15%) but only rare well-formed granulomas (8.5%). The most common hepatic finding was portal lymphohistiocytic inflammation; discrete hepatic granulomas were seen in less than 20% of involved livers. The pathologist must be aware of the broad range of gastrointestinal and hepatic lesions produced by histoplasmosis and, in particular, that well-formed granulomas are rare. Given the appropriate clinical context, histoplasmosis should be considered in both immunocompetent and immunocompromised patients, regardless of pulmonary symptoms, in nonendemic as well as endemic areas.

Adolescent↗
PubMed2000

Theileriosis in a Missouri beef herd caused by Theileria buffeli: case report, herd investigation, ultrastructure, phylogenetic analysis, and experimental transmission.

A 6-year-old Simmental cow infected with Theileria buffeli had a clinical disease characterized by theilerial parasitemia, macrocytic normochromic anemia with acanthocytosis and spherocytosis, lymphoid hyperplasia (lymphocytosis, edematous lymphadenomegaly), dysproteinemia, evidence of liver disease, and a low serum antibody titer against T. buffeli. The cow was in a herd in which all cattle originated in Missouri; 22/75 (29%) of cattle had a theilerial parasitemia and 26/75 (35%) had titers to T. buffeli of > or =1:160. Classification of the Missouri bovine organism as T. buffeli was based on DNA sequencing and comparison to sequences for T. buffeli and Theileria sp. type A obtained from GenBank. Intraerythrocytic veils and piroplasms were seen during transmission electron microscopy. The organism was successfully transmitted to two splenectomized calves, which developed mild anemias while parasitemic. Blood from the second calf was used as the source of T. buffeli antigen for an indirect immunofluorescence antibody test. Theilerial isolates from a Missouri white-tailed deer were also sequenced and resembled Theileria sp. types F and G and were not consistent with the bovine organism.

Animals↗
PubMed2000

Assessing medication appropriateness in the elderly: a review of available measures.

The disproportionate use of medications, combined with age-related pharmacokinetic and pharmacodynamic changes, places older adults at high risk for medication related problems (MRPs). MRPs demonstrate significant morbidity, mortality and economic impact among healthcare systems. The negative outcomes associated with MRPs emphasise the need for more careful and thorough assessments of drug therapy among older adults. In the 1990s a number of methods and instruments were developed to assist in the assessment of medication appropriateness. These tools may be categorised by criteria as: implicit, explicit or one utilising a combination of implicit and explicit criteria. This article reviews these available tools and outlines the advantages and disadvantages of each. In conclusion, those instruments considered to be comprised of both implicit and explicit criteria offer a more thorough assessment of medication appropriateness.

Aged↗
PubMed2000

Passive transfer of colostral immunoglobulin G in neonatal llamas and alpacas.

OBJECTIVE: To evaluate precolostral hypogammaglobulinemia in neonatal llamas and alpacas, to determine when postcolostral peak serum IgG concentrations develop, to determine whether differences in postcolostral serum IgG concentrations between llamas and alpacas exist, and to determine postcolostral half-life of serum IgG in llamas and alpacas. DESIGN: Prospective observational study. ANIMALS: 29 llama and 10 alpaca crias. PROCEDURE: Blood samples were collected prior to suckling and on days 1, 2, and 3 after parturition and analyzed for serum IgG concentration by use of a commercial radial immunodiffusion assay. Additional samples were collected on days 8, 13, and 18 from 8 crias to determine mean half-life of IgG. RESULTS: Llamas and alpacas are born severely hypogammaglobulinemic. Mean serum IgG concentrations for day-1, -2, and -3 samples for llamas were 1,578 mg/dl, 1,579 mg/dl, and 1,401 mg/dl, respectively, and for alpacas were 2,024 mg/dl, 1,806 mg/dl, and 1,669 mg/dl, respectively. Peak serum immunoglobulin concentration developed between days 1 and 2. Mean half-life of IgG for all crias was 15.7 days. CONCLUSIONS AND CLINICAL RELEVANCE: Although increased mortality has been linked to failure of passive transfer, it is clearly possible to raise crias that have low serum immunoglobulin concentrations. Llamas and alpacas do not differ significantly with respect to immunoglobulin absorption or IgG concentration in neonates. The optimal sampling time for passive transfer status is between 1 and 2 days.

Agammaglobulinemia↗
PubMed2000

Reference values for activated coagulation time in cats.

OBJECTIVE: To establish reference values for activated coagulation time (ACT) in cats by use of jugular venipuncture and direct collection of blood into ACT vacuum tubes. ANIMALS: 100 clinically normal cats that were to have elective surgery performed at a private practice. PROCEDURE: Collection of 3 blood samples for ACT measurement was attempted for each cat at the time of elective surgery: sample 1, obtained before sedation; sample 2, tube 1 of 2 consecutive samples obtained from a single venipuncture of the contralateral jugular vein after sedation with acepromazine and ketamine hydrochloride; and sample 3, tube 2 collected immediately following collection of sample 2 without removing the needle from the vein. Venipuncture quality was rated subjectively on a 3-point scale. RESULTS: Median ACT were 95 seconds for each sample group. The middle 95% of values ranged inclusively from 55 to 185 seconds (sample 1), 65 to 135 seconds (sample 2), 45 to 145 seconds (sample 3), and 55 to 165 seconds overall (samples 1, 2, and 3). Significant differences in ACT values were not detected between sample groups. Significant relationships between ACT and venipuncture quality or sex of cat were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: With the ACT protocols used, clinically normal cats had ACT of < 165 seconds. The ACT in cats does not appear to be significantly affected by sex, sedation with acepromazine and ketamine, or by moderately traumatic venipunctures. These results refute widespread statements that ACT should be < 65 seconds in healthy cats. Cats with ACT repeatedly > 165 seconds should be further evaluated for hemostatic disorders.

Acepromazine↗
PubMed1999

Prolongation of primate cardiac allograft survival by treatment with ANTI-CD40 ligand (CD154) antibody.

BACKGROUND: We evaluated whether a humanized anti-CD154 antibody (hu5c8) prolongs primate cardiac allograft survival. METHODS: Heterotopic cardiac allografts were performed between MHC class II-mismatched cynomolgus monkeys. Survival was compared between groups treated with a perioperative dosing of hu5c8 (group 1; n=6), sustained dosing with hu5c8 (group 2; n=3), and control regimens (n=4). All recipients received fresh donor-specific transfusions during surgery. RESULTS: Median graft survival was 49 days (range 14 to 56) in group 1 and 106 days (range 56 to 245) in group 2, compared with 5 days (range 5 to 6) for controls (P<0.05 for all comparisons). Lymphocytic infiltrates were often present in hu5c8-treated grafts with stable contractility. Donor-specific mixed lymphocyte reaction was generally preserved. Vasculitis and cellular intimal proliferation were prevalent in rejected grafts but occurred later and were less prevalent in group 2. CONCLUSIONS: Anti-CD154 antibody markedly prolongs the survival of cardiac allografts in primates and is well tolerated. Sustained dosing with hu5c8 yielded improved survival and may be associated with a lower incidence of vascular pathology. We conclude that hu5c8 therapy is an effective approach for inhibiting acute cardiac allograft rejection in primates.

Animals↗
PubMed1999

The minimum CD34 threshold depends on prior chemotherapy in autologous peripheral blood stem cell recipients.

We analysed 57 patients with non-myeloid malignancies who received a non-purged autologous PBSCT. All had similar mobilisation and conditioning regimens. A high prior chemotherapy score and the number of chemotherapy lines used (P = 0.015 and P = 0.01, respectively) were adverse predictors of CD34 cell yields. Lower CD34 values (P = 0.002) were seen in patients treated with potent stem cell toxins (BCNU, melphalan, CCNU and mustine), designated toxicity factor 4 agents (TF4). All patients infused with grafts containing CD34 cell doses between 1.0 and 2.0 x 10(6)/kg (range 1.25-1.90) engrafted by day 51. The only variable associated with slow platelet recovery was exposure to TF4 (P = 0.007). The majority of patients with CD34 >1.0 x 10(6)/kg achieved rapid and sustained engraftment and the only predictive factor of delayed recovery is prior exposure to stem cell toxins. Potential PBSCT candidates should if possible avoid first line and salvage chemotherapy containing TF4 drugs. We therefore advocate a minimum CD34 threshold of >1.0 x 10(6)/kg in patients without extensive prior chemoradiotherapy, and > or = 2.0 x 10(6)/kg in all other patients.

Adolescent↗
PubMed1999

Use of transdermal amitriptyline gel in a patient with chronic pain and depression.

A man with severe inflammatory bowel disease suffered from chronic abdominal pain and depression. A transdermal amitriptyline gel preparation was compounded since he was unable to take drugs orally Serum concentrations of amitriptyline and its active metabolite nortriptyline were measured over 24 hours. Symptoms of depression were monitored before starting transdermal therapy and at the end of 6 weeks. Pain symptoms and amitriptyline adverse drug events were monitored daily Steady-state serum concentrations of drug and metabolite were within the therapeutic range over 24 hours. The patient reported that his mood was improved but his abdominal pain remained unchanged. Transdermal amitriptyline gel was well tolerated and is an alternative delivery system in patients unable to take drugs orally.

Administration, Cutaneous↗
PubMed1999

Role of platelet activating factor in development of thrombocytopenia and neutropenia in dogs with endotoxemia.

OBJECTIVE: To determine the role of platelet activating factor (PAF) in lipopolysaccharide (LPS)-induced thrombocytopenia and neutropenia in dogs. ANIMALS: 42 dogs. PROCEDURES: Blood samples were obtained from dogs given LPS (40 microg/kg of body weight; n = 16), PAF (1 microg/kg; 6), PAF (5 microg/kg/h for 90 minutes; 4), or physiologic saline (0.9% NaCl) solution (0.1 ml/kg/h for 90 minutes; 3) IV to monitor changes in blood cell counts, using automated counters and blood smears stained with Giemsa. Blood samples were also obtained from dogs given LPS (40 microg/kg) that had (n = 5) or had not (6) been treated beforehand with TCV-309, a potent PAF antagonist. Concentration of PAF in blood was determined by use of 125I-radioimmunoassay in dogs given LPS at 1 mg/kg (n = 3) and 40 microg/kg (9). RESULTS: Thrombocytopenia and neutropenia were found in all dogs except those given saline solution. The LPS-induced thrombocytopenia was significantly suppressed by prior treatment with TCV-309. The PAF concentrations increased markedly 1 hour after injection of 1 mg/kg of LPS and increased slightly but significantly 10 minutes after injection of 40 microg/kg of LPS. CONCLUSION AND CLINICAL RELEVANCE: PAF plays an important role in the development of LPS-induced thrombocytopenia and neutropenia in dogs. Control of PAF production, PAF-induced effects, or both may be important in the treatment of dogs with gram-negative bacterial infections and associated thrombocytopenia and neutropenia.

Animals↗
PubMed1998

Children's narratives following traumatic brain injury: linguistic structure, cohesion, and thematic recall.

Narrative discourse and intellectual functioning were examined 3 years following traumatic brain injury (TBI) in children 1 to 8 years of age at the time of injury. The language-impaired TBI group (n = 9) had language deficits during the subacute stage of recovery; their performance was contrasted with that of a TBI comparison group equated on neurologic and demographic variables that did not show subacute language impairment (n = 8) and a sibling comparison group (n = 9). The language-impaired TBI group had lower Verbal and Full-Scale IQ scores and produced fewer words and utterances than the sibling group on a story retelling task; their stories were characterized by fewer complete referential and lexical ties and more referential errors, indicating difficulty conjoining meaning across sentences. The language-impaired TBI group recalled approximately one-third of the propositions needed to maintain the story theme and made more errors sequencing the propositions than either the TBI or the sibling comparison groups. Group differences were not obtained on the Performance IQ scores or on measures of rate or fluency of speech production, mazes, use of conjunctives, or naming errors. The discourse deficiencies of children with TBI and acute language impairment were most pronounced at the level of cognitive organization of the text reflecting text macrostructure and were least apparent at the level of lexical and sentential organization reflecting text microstructure. Results are discussed in terms of the vulnerability of developing language abilities to disruption by brain injury.

Brain Injuries↗
PubMed1998

The significance of microabscesses in liver transplant biopsies: a clinicopathological study.

Parenchymal microabscesses (MA) in liver transplant biopsies are frequently associated with cytomegalovirus (CMV) infection. However, other potential causes of MA have not been fully investigated. We studied additional etiologies for MA via histological evaluation and clinicopathological correlation. Three hundred seventy-two liver transplant biopsies from 97 patients (from 1991 to 1997) were reviewed and stained immunohistochemically for CMV. Numerous histological features were evaluated including size and number of MA, lobular and portal inflammation, and cholestasis. Medical records were reviewed for radiographic, laboratory, and other clinical data from the time of biopsy. The chi2 or Fisher's Exact test and ANOVA with adjusted multiple comparisons were used to determine statistical significance. Sixty-two of 372 biopsies (17%) from 43 patients contained MA. Biopsies were obtained between 4 days and 2.3 years posttransplant (median, 14 days). Nineteen percent of biopsies had CMV infection at the time of biopsy; 27% were associated with other bacterial, viral, or fungal infections; 10% had graft ischemia; 15% had biliary obstruction/cholangitis; 3% had a combination of ischemia and sepsis; and no explanation was found in 26% of biopsies. Numerous MA within a biopsy (>9) correlated with CMV infection (P <.005); no other histological features, including size of MA, correlated with the etiology of MA. Overall, 43 of 97 (44%) liver transplantation patients at our institution had biopsies demonstrating MA at some point in their posttransplantation course. CMV infection appears responsible for only a minority of cases. MA, although nonspecific, are an important histological finding in numerous conditions that may have a significant impact on both graft survival and overall patient morbidity.

Abscess↗
PubMed1998

Spatial measurement of oxygen levels during photodynamic therapy using time-resolved optical spectroscopy.

Tissue oxygenation is one of the key dosimetric factors involved in the application of photodynamic therapy (PDT). However, quantitative studies of oxygenation levels at and surrounding the treatment site have been lacking both before, during and after treatment. With the recent development of sensitive, non-invasive, optical spectroscopic techniques based on oxygen-dependent phosphorescence quenching of probe compounds, oxygenation levels can now be measured quantitatively at selected sites with spatial resolution on the millimeter scale. We present results using the phosphorescent compound, palladium meso-tetra(carboxyphenyl)porphine, for measurement of in vivo microvascular oxygen tensions in rat liver during PDT. Time-resolved phosphorescence detection was carried out using fibre-optic sensoring, and oxygen tensions were determined from the phosphorescence lifetimes using Stern-Volmer analysis. During PDT treatment using 5-aminolaevulinic (ALA) acid-induced protoporphyrin IX (PPIX) with a 50 mg/kg ALA dose, oxygen levels near the irradiation fibre placed on the surface of the liver showed a significant decrease by a factor of ten from 20 to 2 torr after an energy dose of 60 J using 100 mW at 635 nm. Areas farther from the treatment site which were exposed to lower light doses exhibited lower reductions in oxygen levels. This spectroscopic technique is a highly sensitive means of investigating tissue oxygenation during and after treatment, and should help not only to advance the understanding of hypoxia and microvascular damage in the PDT mechanism but also contribute to improving the dosimetry of PDT.

Aminolevulinic Acid↗
PubMed1998

Memory functions in children with early hydrocephalus.

Children with arrested, shunted, and no hydrocephalus were compared on verbal and nonverbal memory tasks assessing multiple components of memory. A gradient of severity was hypothesized, with the shunted hydrocephalus group expected to exhibit the most significant memory impairments and the arrested group expected to perform more poorly than children with no hydrocephalus. Etiologies of prematurity, spina bifida, and aqueductal stenosis were represented by 157 participants. Results supported the hypothesis; the shunted hydrocephalus group performed poorer on all memory measures. Differences for the arrested group were less frequently statistically significant relative to children with no hydrocephalus. Irrespective of etiology, the shunted hydrocephalus group exhibited a pattern of performance suggestive of encoding and retrieval deficits on both verbal and nonverbal tasks, showing a pervasive disturbance of memory processes.

Analysis of Variance↗
PubMed1998

A trend towards an increased incidence of chronic graft-versus-host disease following allogeneic peripheral blood progenitor cell transplantation: a case controlled study.

Allogeneic peripheral blood progenitor cell transplantation (alloPBPCT) is increasingly used as an alternative to bone marrow transplantation (alloBMT). Early data suggest that the incidence and severity of acute graft-versus-host disease (GVHD) following alloPBPCT is no higher than that seen with alloBMT, despite the increased number of cytotoxic T cells infused with mobilised blood. We compared 12 patients undergoing alloPBPCT with 12 well-matched alloBMT controls. All patients received identical GVHD prophylaxis. No T cell depletion or CD34 purification was performed. Median engraftment times for neutrophils >0.5 x 10(9)/l and platelets >20 x 10(9)/l were 14 and 12 (alloPBPCT) and 21 and 23 days (alloBMT), respectively (P = 0.0035 and P = 0.002). There was no difference in antibiotic requirements (P = 0.83), platelet support (P = 0.59) or days in hospital (P = 0.51). After alloPBPCT, five patients developed > or =grade II acute GVHD vs five patients after alloBMT (P = 0.99). There was one death (alloBMT) at 100 days and three at 1 year (all due to relapse). There was one death at 100 days with alloPBPCT, and 11 patients remain alive (range 9-21 months) to date. Chronic GVHD occurred in five patients in the PBPC arm and one patient in the BM arm (P = 0.14). This case-controlled analysis indicates that alloPBPCT results in more rapid engraftment kinetics but in no significant difference in transplant-related morbidity or mortality. There is no difference in the incidence of acute GVHD. However, there is a trend towards increased incidence of chronic GVHD in patients allografted with PBPC. Prospective randomised trials are required to determine further the role of alloPBPCT.

Acute Disease↗