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T M Schmitz

Publications and source records attributed to T M Schmitz.

7 recordsLinked to original sources
PubMed2001

Validation of a diagnostic multiplex polymerase chain reaction assay for infectious posterior uveitis.

OBJECTIVE: To validate a multiplex polymerase chain reaction (PCR) assay capable of simultaneously screening vitreous biopsy specimens for a panel of common pathogens in posterior uveitis. METHODS: A multiplex PCR assay using novel primer sets for cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Toxoplasma gondii was developed. The sensitivity of the assay was determined for purified pathogen DNA. Twenty-one vitreous specimens from patients with posterior uveitis were tested by both multiplex and monoplex PCR. RESULTS: Fewer than 10 genomes of VZV and fewer than 100 genomes of HSV, CMV, and T gondii could be detected using the new primer sets. When used in multiplex, the assay lost less than 1 log of sensitivity. Monoplex PCR detected pathogen DNA in 18 of 21 patient samples; multiplex PCR detected pathogen DNA in 15 of the 18 samples positive by monoplex PCR. None of 10 negative control samples were positive for pathogen DNA. CONCLUSIONS: Multiplex PCR has adequate sensitivity to simultaneously screen a substantial differential diagnosis for posterior uveitis in a single reaction, without loss of specificity. This assay may reduce the time and cost involved in PCR-based molecular diagnostics of infectious pathogens. CLINICAL RELEVANCE: Mutiplex PCR may allow rapid diagnosis of infectious posterior uveitis.

Animals↗
PubMed2000

Functional redundancy of cryptochromes and classical photoreceptors for nonvisual ocular photoreception in mice.

The daily light-dark (LD) cycle exerts a powerful influence on the temporal organization of behavior and physiology. Much of this influence is preserved in behaviorally blind retinally degenerate mice; the photoreceptors underlying this nonvisual phototransduction are unknown. The mammalian eye contains at least two classes of photoactive pigments, the vitamin A-based opsins and the vitamin B(2)-based cryptochromes. To genetically define the roles of these pigments in light modulation of behavior, we generated rd/rd;mCry1(-)/mCry1(-);mCry2(-)/mCry2(-) mutant mice lacking rods and most cones as well as both cryptochrome proteins. The response of the mutant mouse to photic input was analyzed at both behavioral and molecular levels. Behaviorally, mice lacking either classical photoreceptors or cryptochromes exhibited strongly rhythmic locomotor responses to 10 and 100 lux daily LD 12 h/12-h cycles; however, triple mutant mice carrying both cryptochrome and retinal degenerate mutations were nearly arrhythmic under both LD cycles and in constant darkness. At the molecular level, the light induction of c-fos transcription in the suprachiasmatic nucleus was markedly reduced in the triple mutant mouse compared with either rd/rd or cryptochrome mutant mice. These data indicate that classical opsins and cryptochromes serve functionally redundant roles in the transduction of light information to behavioral modulation and suggest a pleomorphic role for cryptochromes in both photoreception and central clock mechanism.

Animals↗
PubMed1996

Estrogen increases the bradycardia elicited by central administration of the serotonin1A agonist 8-OH-DPAT in conscious rats.

Studies determined if estradiol modulates cardiovascular responses evoked by administration of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), a 5-HT1A receptor agonist, into the lateral cerebral ventricle. 8-OH-DPAT (100 nmol) produced equivalent decreases in blood pressure in male and ovariectomized female (OVX) rats with or without estradiol replacement. By contrast, the bradycardia elicited by 8-OH-DPAT (3-100 nmol) was greatest in OVX rats with estradiol. Estradiol did not alter the bradycardia produced by electrical stimulation of the vagus nerve. In summary, estradiol selectively enhanced the bradycardia elicited by 8-OH-DPAT suggesting that estrogen modulates the function of central 5-HT1A receptors regulating heart rate.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1994

Aging enhances serotonergic cardiovascular blockade by ketanserin in conscious rats.

We recorded cardiovascular responses to serotonin (5-HT) and to two selective serotonergic agonists following ketanserin treatment in 3 groups of conscious rats aged 4, 14 or 24 months. The selective agonists were DOI (5-HT2 agonist), and phenylbiguanide (5-HT3 agonist). Before ketanserin treatment, pressor responses to 5-HT or DOI were larger while reflex bradycardic responses to 5-HT or phenylbiguanide were smaller in 14- and 24-month than in 4-month-old rats. Ketanserin treatment lowered blood pressure consistently, and the ensuing hypotension was more pronounced in 14- and 24-month than in 4-month-old rats. Pressor responses to DOI were attenuated similarly in all rats, but those to 5-HT were reversed to depressor responses whose magnitude was smaller in 14- and 24-month than in 4-month-old rats. On the other hand, bradycardic responses to 5-HT and phenylbiguanide were enhanced in 14- and 24- but not in 4-month-old rats. Our results indicate that even before ketanserin was given, old rats had enhanced pressor responses to 5-HT2 agonists together with weakened bradycardic responses to 5-HT3 agonists. Following ketanserin treatment, 5-HT2 pressor responses were blocked while 5-HT3 bradycardic responses were enhanced but only in old rats. These results are compatible with the interpretation that the more pronounced hypotension produced in old rats by ketanserin is due to two complementary effects on serotonergic receptors: blockade of 5-HT2 pressor responses coupled with selective enhancement of 5-HT3 bradycardic responses.

Aging↗
PubMed1991

The semi-prone position in ARDS: five case studies.

Several studies have reported significant improvement in arterial blood oxygenation with use of the prone position in ARDS. This study, undertaken to examine the effect of the semi-prone position in patients with ARDS, resulted in several important considerations for clinical nursing practice.

Adolescent↗