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Biomedical subjects

G Mathews

Publications and source records attributed to G Mathews.

15 recordsLinked to original sources
PubMed2000

The role of clinical suspicion in evaluating a new diagnostic test for active tuberculosis: results of a multicenter prospective trial.

CONTEXT: In laboratory trials, nucleic acid amplification tests for the diagnosis of tuberculosis (TB) are more accurate than acid-fast bacilli (AFB) smear microscopy and are faster than culture. The impact of these tests on clinical diagnosis is not known. OBJECTIVE: To assess the performance of a nucleic acid amplification test, the enhanced Mycobacterium tuberculosis Direct (E-MTD) test, against a uniform clinical standard stratified by level of clinical suspicion. DESIGN: Prospective multicenter trial conducted between February and December 1996, documenting the clinical suspicion of TB at enrollment and using final comprehensive diagnosis as the criterion standard. SETTING: Six urban medical centers and 1 public health TB clinic. PATIENTS: A total of 338 patients with symptoms and signs consistent with active pulmonary TB and complete clinical diagnosis were stratified by the clinical investigators to be at low (< or =25%), intermediate (26%-75%), or high (>75%) relative risk of having TB. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of the E-MTD test in clinical suspicion of groups with low (n = 224); intermediate (n = 68); and high (n = 46) clinical suspicion of TB. RESULTS: Based on comprehensive clinical diagnosis, sensitivity of the E-MTD test was 83%, 75%, and 87% for low, intermediate, and high clinical suspicion of TB, respectively, and corresponding specificity was 97%, 100%, and 100% (P = .25). Positive predictive value of the E-MTD test was 59% (low), 100% (intermediate), and 100% (high) compared with 36% (low), 30% (intermediate), and 94% (high) for AFB smear. Corresponding negative predictive values were 99%, 91%, and 55% [corrected] (E-MTD test) vs 96%, 71%, and 37% (AFB smear). CONCLUSIONS: For complex diagnostic problems like TB, clinical risk assessments can provide important information regarding predictive values more likely to be experienced in clinical practice. For this series, a clinical suspicion of TB was helpful in targeting areas of the clinical spectrum in which nucleic acid amplification tests can make an important contribution.

Adult↗
PubMed1999

Evaluation of the enhanced amplified Mycobacterium tuberculosis direct test for direct detection of Mycobacterium tuberculosis complex in respiratory specimens.

OBJECTIVE: To evaluate the performance of the enhanced Mycobacterium Tuberculosis Direct Test (E-MTD), for the direct detection of M tuberculosis complex (MTBC) in respiratory specimens. DESIGN: Two hundred seventy-four respiratory specimens from 151 patients in respiratory isolation were tested with the E-MTD, and the results were compared with the results of mycobacterial smear, culture, and the earlier form of the test, MTD-1. RESULTS: Forty-one specimens were culture positive for mycobacteria (20 MTBC and 21 nontuberculous mycobacteria), 23 of which were smear positive (16 MTBC, 7 nontuberculous mycobacteria). Twenty-four specimens were positive by E-MTD, and 21 were positive by MTD-1. Of the 20 MTBC culture-positive specimens, 19 were positive by the E-MTD and 19 were positive by the MTD-1. The remaining specimens were MTBC negative by all methods. After resolution of discrepancies, the sensitivity, specificity, and positive and negative predictive values were 95.2%, 100%, 100%, 99.6% for the MTD-1 and 95.2%, 98.8%, 87.0%, and 99.6%, for the E-MTD. For the E-MTD smear-positive and smear-negative specimens, these same values were 93.8%, 100%, 100%, and 87.5% and 100%, 98.8%, 62.5%, and 100%, respectively. CONCLUSION: The results suggest that the E-MTD is a reliable method for the direct detection of MTBC in smear-positive respiratory specimens.

Bacteriological Techniques↗
PubMed1995

Fatal outcome of jugular vein cannulation.

We describe the case of a woman who had cannulation of the internal jugular vein for the placement of a hemodialysis catheter. The procedure was unsuccessful and resulted in a retropharyngeal hematoma, which in turn caused severe compression on a carotid artery that was already severely narrowed by atherosclerosis. This resulted in massive cerebral hemispheric infarction and death. During the course of hospitalization, ultrasonography, computed tomography, and angiographic studies were done. Cannulation of neck vessels in patients with bleeding diatheses must be done with caution, especially in the presence of severe stenotic disease of the carotid arteries.

Aged↗
PubMed1995

Self-injury and incontinence in psychogenic seizures.

Two patients who incurred significant injuries during psychogenic seizures prompted us to do a telephone survey of self-injury and incontinence in 102 consecutive patients diagnosed with psychogenic seizures by EEG-closed-circuit TV (EEG-CCTV) monitoring. Seventy-three patients (or a close family member or friend) were reached by telephone and responded to our survey. During typical attacks of psychogenic seizures, 40% reported injuries, 44% reporting tongue biting, and 44% reported urinary incontinence. Suicide attempts were reported by 32% and were more common in those with self-injury and urinary incontinence. We compared the results of patients with psychogenic seizures with those of 30 patients with refractory epilepsy documented by ictal recordings, using a similar telephone survey. Injuries of all types were more commonly reported by epilepsy patients. Burn injuries were reported only by patients with epilepsy. Suicide attempts were more commonly reported by the psychogenic seizure group. Self-injury and incontinence are commonly reported by psychogenic seizure patients. In view of their significant association with suicide attempts, they may indicate an underlying depression.

Adolescent↗
PubMed1994

Regenerating sciatic nerve axons contain the adult rather than the embryonic pattern of microtubule associated proteins.

Microtubule associated proteins play a central role in the control of axon growth. We have used immunohistochemical techniques to establish which microtubule-associated proteins are present in the rat hindlimb spinal cord, dorsal root ganglia and peripheral nerves during axonal growth during embryogenesis, in adulthood, and during regeneration of crushed sciatic nerves. During embryogenesis microtubule-associated protein-1b and tau are present in all neurons and axons, microtubule-associated protein-2 is present in neurons but not in axons, and there is no microtubule-associated protein-1a. In adults, microtubule-associated protein-1a and microtubule-associated protein-1b are present in all sciatic nerve axons and in motor and dorsal root ganglion neurons. Tau, in its adult form, is present in many fine probably sensory axons, but not in most larger axons, and in motor and sensory neurons. Microtubule-associated protein-2 is present only in neurons. During regeneration the pattern of microtubule-associated protein expression retains the adult pattern. All regenerating axons contain microtubule-associated protein-1a and microtubule-associated protein-1b, none contain microtubule-associated protein-2, and a subset of fine axons contain tau. There is no detectable change in microtubule-associated protein expression by motoneurons. While axons are clearly able to regenerate without either microtubule-associated protein-2 or tau, tau containing axons appear to regenerate faster than those which lack it. It is possible that the failure of neurons to recapitulate the embryonic pattern of microtubule-associated protein expression during regeneration could be a reason why regenerative axon growth is slower and less vigorous than axon growth in embryos.

Animals↗
PubMed1987

A comparative study of transcutaneous electrical nerve stimulation (TENS), entonox, pethidine + promazine and lumbar epidural for pain relief in labor.

Analgesic effect, labor outcome, safety and consumer satisfaction were compared in 170 primigravid women; 50 using TENS initially for pain relief, 20 using entonox, 50 pethidine + promazine and 50 lumbar epidural. 88% choosing epidural related it fully effective. 90% using entonox, 96% using TENS and 54% given pethidine + promazine found partial relief. 82% of patients given TENS and 80% given pethidine + promazine required additional analgesia. This was also needed by one of the 20 patients choosing entonox. Women using entonox alone had the shortest labors and women using lumbar epidural, the longest. Operative delivery was significantly more common in women receiving lumbar epidural. No significant inter-group differences were noted in cord pH or Apgar scores. Parturients and midwives both gave high consumer satisfaction ratings to all methods--except for pethidine + promazine, whose use must therefore be questioned. The analgesic efficacy of lumbar epidural outweighs any possible side effects. Entonox appears suited to those able to cope with the earlier part of labor, drug-free. Realization of the potential of TENS requires the design of machines specifically to cope with the quality of the pain of labor.

Anesthesia, Epidural↗
PubMed1986

Pain relief in labour using transcutaneous electrical nerve stimulation (TENS). A TENS/TENS placebo controlled study in two parity groups.

The analgesic effects of transcutaneous electrical nerve stimulation (TENS) in labour and effects on outcome were investigated in a double-blind TENS/TENS placebo controlled trial in 100 primigravidae and 50 women in their third labour. There were no differences between the TENS and the TENS placebo users in terms of pain concept or relief, and only 12 and 13% of primigravidae and 48 and 39% of the para 2 women completed labour without requiring other analgesia in their respective groups. The primigravidae who used either TENS or TENS placebo alone had shorter labours than those who required further analgesia. Although the outcome of labour for mother and infant were similar in the two groups, there was a higher operative delivery rate in women who also had epidural analgesia. There were highly significant differences between the TENS and the TENS placebo users in terms of favourable and unfavourable comments by the mothers and the midwives at 1 and 24 h after delivery. The evident consumer satisfaction for TENS suggests TENS has a part to play in analgesia in labour but the equivocal findings in terms of factors associated with pain relief points to the need for apparatus more specifically designed to cope with the special characteristics of the pain of labour.

Clinical Trials as Topic↗
PubMed1979

Hypervascular cavernous angioma at angiography.

Arteriovenous malformations usually do not present any diagnostic difficulty on the angiograms. However, small cryptic and cavernous angiomas cannot be demonstrated directly by arteriography because of either sluggish circulation or thrombosis. The present communication documents a relatively rare case of histologically proven cavernous angioma with a hypervascular pattern on the arteriogram.

Brain Neoplasms↗
PubMed1978

Cerebral mucormycosis--a case report.

A case of cerebral fungal granuloma with histological evidence of vasculitis is reported and the literature briefly reviewed. The value of surgery and chemotherapy for this entity which cured the patient without any sequelae of the disease process or chemotherapeutic agent is emphasized.

Adult↗