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Biomedical subjects

M Mathews

Publications and source records attributed to M Mathews.

At least 19 recordsLinked to original sources
PubMed2000

Halicephalobus gingivalis (H. deletrix) infection in two horses in southern California.

Two horses, a 16-year-old male Holsteiner and a 5-year-old male miniature horse, were diagnosed with halicephalobiasis at the California Veterinary Diagnostic Laboratory System, San Bernardino Branch, in April and June of 1998. Over a period of 4 weeks, the Holsteiner horse developed renal dysfunction, blepharospasm, and blindness in the right eye. A 15-cm-diameter mass was detected on ultrasound examination in the right kidney. Terminally, the animal developed seizures and was euthanized. The miniature horse had a 6-week-long illness characterized by testicular enlargement and uveitis. This animal developed ataxia and died. Necropsy examination revealed bilateral enlargement of the kidneys in both horses, petechial hemorrhages of the optic nerve (Holsteiner), and a diffusely firm and enlarged left testicle (miniature horse). Microscopic evaluation of tissues revealed granulomatous nephritis, optic neuritis, retinitis, and encephalitis in both horses and orchitis in only the miniature horse with intralesional rhabditiform nematodes. Halicephalobus gingivalis was found in the urine sediment of both animals and in semen of the Holsteiner horse.

Animals↗
PubMed1999

Production of beta-defensin antimicrobial peptides by the oral mucosa and salivary glands.

beta-Defensins are cationic peptides with broad-spectrum antimicrobial activity that are produced by epithelia at mucosal surfaces. Two human beta-defensins, HBD-1 and HBD-2, were discovered in 1995 and 1997, respectively. However, little is known about the expression of HBD-1 or HBD-2 in tissues of the oral cavity and whether these proteins are secreted. In this study, we characterized the expression of HBD-1 and HBD-2 mRNAs within the major salivary glands, tongue, gingiva, and buccal mucosa and detected beta-defensin peptides in salivary secretions. Defensin mRNA expression was quantitated by RNase protection assays. HBD-1 mRNA expression was detected in the gingiva, parotid gland, buccal mucosa, and tongue. Expression of HBD-2 mRNA was detected only in the gingival mucosa and was most abundant in tissues with associated inflammation. To test whether beta-defensin expression was inducible, gingival keratinocyte cell cultures were treated with interleukin-1beta (IL-1beta) or bacterial lipopolysaccharide (LPS) for 24 h. HBD-2 expression increased approximately 16-fold with IL-1beta treatment and approximately 5-fold in the presence of LPS. Western immunoblotting, liquid chromatography, and mass spectrometry were used to identify the HBD-1 and HBD-2 peptides in human saliva. Human beta-defensins are expressed in oral tissues, and the proteins are secreted in saliva; HBD-1 expression was constitutive, while HBD-2 expression was induced by IL-1beta and LPS. Human beta-defensins may play an important role in the innate defenses against oral microorganisms.

3T3 Cells↗
PubMed1998

Low levels of ionic mercury modulate protein tyrosine phosphorylation in lymphocytes.

The ability of ionic mercury to induce protein tyrosine phosphorylation in mouse spleen cells and in the mouse WEHI-231 B-cell lymphoma was investigated. We have confirmed previous studies which showed that exposure to high levels (several hundred microM) of mercury lead to very large increases in the level of protein tyrosine phosphorylation in these cell systems. However we have also demonstrated that low levels (in the order of 0.1 to 1.0 microM) of mercury also significantly upregulate protein tyrosine phosphorylation. Mercury induced protein tyrosine phosphorylation is inhibited by the mercury chelator penicillamine and by pretreating treating target cells with the sulfhydryl blocking reagent N-hydroxymaleimide. These results suggest that exposure to low levels of mercury could potentially interfere with lymphocyte signal transduction and so offer a possible explanation as to how mercury exposure could lead to immune cellular dysfunction. On a molecular level, the results suggest that the site(s) of action with respect to mercury dependent induction of protein tyrosine phosphorylation is likely a free disulfide group or groups located on the outer leaflet of the plasma membrane.

Animals↗
PubMed1997

Randomized comparison of G-CSF + GM-CSF vs G-CSF alone for mobilization of peripheral blood stem cells: effects on hematopoietic recovery after high-dose chemotherapy.

Fifty patients with either lymphoid or selected solid tumor malignancies were apheresed an identical number of times for PBSC collection after being randomized to receive either G-CSF 10 microg/kg/day alone (arm I), or G-CSF at the same dose with GM-CSF 5 microg/kg/day (arm II). Growth factor(s) was/were given as the stem cell mobilizing agent for 5 days before the start of PBSC collection, and were continued throughout the 4 days of apheresis. Aspiration and cryopreservation of autologous bone marrow occurred on day 3 or 4 of growth factor(s). Thirty-one of 50 patients received one cycle only at time of evaluation, and 19 patients received two cycles of HDCT, each supported with PBSC with or without autologous bone marrow. No patients received growth factors post-autologous stem cell transplant, unless the absolute neutrophils count (ANC) failed to recover to > or = 100/microl by day +18 post-transplant. The median number of days to recovery of ANC to 100/microl, 500/microl and 1000/microl, and of platelet counts to 20000/microl, 50000/microl and 100000/microl after either cycle 1 or cycle 2 of HDCT and the number of febrile days and platelet and PRBC transfusion requirements was not significantly different between the two arms of the study. The duration of hospitalization was similar between study arms for cycle 1 of HDCT, but was 3.5 days less with arm II compared to arm I (P = 0.0248) for cycle 2 of HDCT. The bone marrow buffy coat and PBSC product mononuclear cell count (x 10(8)/kg) and CD34+ cell count (x 10(6)/kg) collected by each method of stem cell mobilization was not significantly different. There is questionable clinical benefit with PBSC products mobilized with the combination of G-CSF and GM-CSF vs G-CSF alone. Perhaps different dosages, schedules, or other growth factor combinations with G-CSF might enhance these differences.

Adult↗
PubMed1989

Hypernatremia in the elderly.

Hypernatremia is common in elderly persons, who may present with signs that are easily overlooked. Prompt diagnosis and appropriate therapy can sometimes lead to a remarkable recovery. To avoid cerebral edema, rehydration must be accomplished gradually over 48 to 72 hours. The recommended replacement for the first 24 hours is approximately 30 percent of the estimated water loss.

Aged↗
PubMed1985

Dissecting aneurysms of head and neck.

We analyzed four personal cases and 51 reported cases of dissecting aneurysms of the arteries of the head and neck. Subintimal dissection more commonly affects the intracranial vessels before age 40. In contrast, medial dissection tends to affect extracranial vessels after age 30. Vertebrobasilar dissection more variably affects either arterial plane. The reasons for these differing patterns of dissection are still not clear. In young subjects, the subintimal layer appears to be more susceptible; in contrast, the media becomes increasingly vulnerable with age, particularly in the presence of acquired medial disease.

Adolescent↗
PubMed1984

Attention to stimuli, verbal labeling, and question asking in referential communication.

This study evaluated the effects of age, the dyad's attention to and verbal labeling of target and nontarget stimuli, and listener instructions to ask questions on referential communication in 48 five-year-old and 48 eight-year-old dyads. A MANOVA for dyad activities indicated both age and dyad-activities differences. The dyads that located and verbally labeled the critical attributes were superior to the dyads that simply located the critical attributes and to control dyads on speaker performance. A MANOVA for listener instructions to ask questions yielded no age differences on the number of questions asked and no interaction between age and instructions to ask questions. It indicated that listeners instructed to ask questions and control listeners differed on the number of questions asked but not on communication accuracy.

Attention↗
PubMed1981

Vietnamese attitudes towards maternal and infant health.

Behavioural and dietary precautions, observed both by ethnic Vietnamese and by Vietnamese-Chinese women during pregnancy and the puerperium, derive from the humoral medical classification of foodstuffs and physiological states. Migration to Australia has led only to minor modification of the birth prescriptions, which provide women with a means of dealing with the physiological-medical and psychological-personal changes brought about by pregnancy and delivery. However, traditional practices of infant feeding have largely been abandoned in favour of a short period either of breast feeding only or of exclusive bottle feeding and the early introduction of solids.

Attitude to Health↗
PubMed1981

Hormone profile in lepromatous leprosy. A preliminary study.

In a preliminary study, 11 male patients with lepromatous leprosy were evaluated with regard to endocrinopathy and hormonal status. Basal circulating hormone levels were estimated with a view to correlating the biochemical findings and clinical features. Thyroid hormones T3 and T4, Free Thyroxine Index (FTI), TSH, and cortisol were within normal limits, indicating that further study of these hormones would not be worthwhile. The finding of elevated levels of prolactin as well as the gonadotrophins LH and FSH, however, promises to yield more valuable information if studied in greater detail in a larger group of patients.

Adult↗
PubMed1980

Communication Accuracy in Lower- and middle-SES children as a function of task abstraction.

The Communication encoding performance of lower-SES black, lower-SES white, and middle-SES white children was evaluated when the same familiar stimuli for eliciting communication were presented at three different levels of abstraction. No differences were found between social-class groups. Performance did not differ as a function of level of abstraction. The social group X level of abstraction interaction was not significant. Thus the level of abstraction of the stimuli does not impede the communication encoding performance of lower-SES children. Previous findings of social-class differences in communication accuracy may be an artifact of stimuli that are not equally familiar to all groups.

Child↗
PubMed1980

Septic arthritis in hemodialyzed patients.

Six episodes of septic arthritis involving 5 patients and eleven joints were documented in the last 7 years in a population receiving 450 patient-years of dialysis treatment. The same micro-organisms were often cultured simultaneously from the joint, blood and/or arteriovenous fistula, suggesting hematogenous spread. A tendency toward multiarticular involvement was also observed. Early diagnosis is mandatory to avoid severe joint damage. Since such patients have other potential causes of arthritis and periarticular pain not due to infection, it is important to culture the joint fluid promptly whenever the possibility of infection exists.

Adult↗