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Biomedical subjects

J Newmark

Publications and source records attributed to J Newmark.

At least 19 recordsLinked to original sources
PubMed2000

Antiphospholipid antibodies, ischemic stroke in young adults, and calcium supplementation: a hypothesis.

The proper treatment of younger patients who have suffered ischemic stroke and who have no stroke risk factors other than antiphospholipid antibodies is unsettled. We propose a rationale to support adding dietary supplementation with calcium and vitamin D to the present standard regimen of anticoagulant therapy for these patients. We expect that the benefits from this additional therapy will prove additive. Proving this hypothesis will require large numbers of patients unlikely to present to any one center. The military health care system is well suited to such a study.

Adult↗
PubMed2000

A field-expedient algorithmic approach to the clinical management of chemical and biological casualties.

Warriors on the modern battlefield face considerable danger from possible attack with chemical and biological weapons. Aggravating this danger is the fact that medical resources at the lowest echelons of care, already likely to be strained to capacity during modern conventional combat, are at present inadequate to handle large numbers of chemical or biological casualties. Complicating this problem further is the austere nature of diagnostic modalities available at lower echelons. With this in mind, and given the urgency required to adequately manage chemical and biological casualties, it is likely that such casualties will initially require significant empiric care in the absence of a definitive diagnosis. Such care under field conditions, often rendered by relatively inexperienced medical personnel, might best be provided using an algorithmic approach. We have developed such an algorithm.

Algorithms↗
PubMed1999

Musicians' dystonia: the case of Gary Graffman.

A professional pianist developed career-ending focal dystonia. There is a possible relationship between the pianist's syndrome and his past playing history. Although the patient has derived very little benefit from various treatment modalities, his candor regarding his impairment indirectly led to the establishment of performing arts medicine as a recognized subspecialty of occupational medicine.

Dystonic Disorders↗
PubMed1999

Delayed unilateral post-traumatic tremor: localization studies using single-proton computed tomographic and magnetic resonance spectroscopy techniques.

We present the case of a 46-year-old former U.S. Marine who developed unilateral dystonic tremor responsive to anticholinergic medications 13 years after contralateral, combat-induced head trauma. Although conventional neuroimaging techniques showed normal brain anatomy, single-proton computed tomographic scans demonstrated hypometabolism ipsilateral to the area of old trauma. Proton echoplanar spectral imaging demonstrated decreased signal in this same area on creatine imaging, which normalized on anticholinergic medication. Choline imaging on medication showed a signal void in the clinically suspected basal ganglia-thalamus region. We believe that these results indirectly suggest a trans-synaptic origin of the patient's movement disorder.

Basal Ganglia Diseases↗
PubMed1998

Use of medical specialties in medical operations other than war: lessons from Saudi Arabia.

From the experience of a U.S. Army Air Defense Artillery "battalion-plus" task force serving a 6-month rotation in the Kingdom of Saudi Arabia, we compiled the requirements for specialty consultations on deployed personnel in the predeployment screening phase, during deployment (including both inpatient hospitalizations and medical evacuations), and immediately upon return to home station. We required a wide variety of specialty expertise. In every phase of the operation, we consulted orthopedic surgery most often. Nonsurgical and surgical specialists were consulted in roughly equal numbers. Almost every field of adult medicine was represented in our sample. The distribution of consultations across specialties differs from what would be expected in combat but is similar to that seen in the few other studies of comparable populations. Excellent host nation support allowed us to use specialty expertise to an almost ideal extent. These data represent the most complete "snapshot" that has been taken of the requirements for specialty medical consultations in a military operation other than war (MOOTW). They demonstrate that under MOOTW conditions, even a healthy Army population requires the assistance of a full panel of medical specialties. They should serve as a benchmark for planners estimating the medical specialty needs that the Army must provide. Military medicine must provide access to essentially all medical specialties for personnel deployed under MOOTW conditions, whether through host nation support, telemedicine, or medical evacuation.

Adult↗
PubMed1995

Persian Gulf illnesses: preliminary neurological impressions.

We review the initial impressions of the first 65 patients evaluated neurologically at Madigan Army Medical Center as mandated by the Comprehensive Clinical Evaluation Program of the Department of Defense for Persian Gulf veterans. No consistent patterns of neurologic disease or new neurologic syndromes emerged. Our experience suggests that full neurological evaluation of such patients without a clear history of neurological symptoms is not cost effective. Headaches and sleep difficulties were the two most frequent complaints. We suggest that sleep disorders may be underdiagnosed in active duty populations.

Adult↗
PubMed1991

The focally demyelinated rat fimbria: a new in vitro model for the study of acute demyelination in the central nervous system.

We have produced controlled local demyelination in Wistar rat fimbriae by injection of microliter quantities of the detergent lysophosphatidyl choline (LPC) stereotactically. Six to seven days later the hippocampus and fornix was dissected out en bloc and maintained in vitro for electrical evaluation of conduction through the damaged area. The tissue was then fixed for verification of the lesion by light and electron microscopy. All fimbriae showed a normal conducted action potential with a latency of 0.5 to 1.5 ms when the conduction distance was 4-5 mm. LPC-lesioned fimbriae also showed a later wave with a latency of 4-5 ms. This later wave had the same stimulus-response curve as the primary action potential, but was more sensitive to repeated stimulation. We interpret this wave as evidence of conduction into or through a demyelinated region. LPC-lesioned fimbriae also showed histological evidence of demyelination. This preparation provides an in vitro model for the study of acute local demyelination of central nervous system white matter, such as that induced by multiple sclerosis and other focally demyelinating diseases.

Acute Disease↗
PubMed1991

Increasing extracellular calcium improves conduction in partially demyelinated rat fimbria in vitro.

1. We have tested the effect of changed concentrations of Ca2+ upon demyelination-induced conduction block in rat fimbria in vitro. 2. In a rat fimbria containing a region of acute focal demyelination induced by in vitro microinjection of lysophosphatidyl chloride (LPC) 6 days earlier, raising bath [Ca2+] to 4.4 mM improved conduction through the damaged area, while lowering it to 0.25 mM depressed conduction. 3. A contrary effect, consistent with the well-known effects of extracellular calcium ion on voltage-sensitive channels, was seen in non-lesioned preparations.

Action Potentials↗
PubMed1989

Calcium reverses lidocaine-induced conduction block in rat fimbria in vitro.

1. We have tested the effect of changed concentrations of Ca2+ upon lidocaine-induced conduction block in rat fimbria. 2. With bath [Ca2+] of 0.25 mM, 0.5 mM lidocaine reduced the amplitude of the compound action potential to 20.2% +/- 2.25% of baseline (n = 5). 3. On changing the bath [Ca2+] to 4.4 mM, with no change in lidocaine concentration, the compound action potential increased by 33.5 +/- 6.5%. 4. In the absence of lidocaine, changing bath [Ca2+] had opposite effects. These results replicate findings by others in peripheral nerve.

Action Potentials↗
PubMed1987

Isolated painless manual incoordination in 57 musicians.

Focal motor syndromes are reported in 57 instrumental musicians who presented with painless uncoordinated movement of the upper limbs. Three stereotyped afflictions were noted: flexion of the 4th and 5th fingers in pianists, flexion of the 3rd finger in guitarists, and extension of the 3rd finger in clarinetists. Our patients differed from those with generalised dystonia in that their disabilities were focal, activity-specific, and non-progressive. Because these disabilities represent entrained responses to peripheral stimuli, distinct from progressive dystonias, they may provide insights into control of fine limb movement and sensory triggers of abnormal movement.

Adult↗
PubMed1981

Amygdalin (Laetrile) and prunasin beta-glucosidases: distribution in germ-free rat and in human tumor tissue.

Amygdalin, the gentiobioside derivative of mandelonitrile commonly referred to as Laetrile, is presently under intensive investigation as a potential cancer chemotherapeutic agent. Because of this interest, we investigated the activity of beta-glucosidases that cleave glucose from amygdalin and from prunasin (mandelonitrile monoglucoside) in tissues from germ-free rats and in normal and neoplastic human tissues. Rat and human small intestinal mucosa contain high levels of activity of glucosidases that act on both of these cyanogenic glucosides. Release of glucose from these compounds was not detected in any of the human neoplastic tissues examined in the present study. These observations are consistent with reports of cyanide toxicity through the oral use of amygdalin or prunasin and pose serious questions concerning the alleged tumoricidal effect of amygdalin.

Amygdalin↗