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Biomedical subjects

M A Ross

Publications and source records attributed to M A Ross.

At least 55 records · Page 3Linked to original sources
PubMed1995

Plasma concentrations of carotenoids and antioxidant vitamins in Scottish males: influences of smoking.

OBJECTIVE: To quantify the major carotenoids in plasma of Scottish males and establish which were affected by habitual smoking. DESIGN: Concentrations of carotenoids, vitamin C and vitamin E (alpha and gamma-tocopherol) were determined in plasma samples from 50 fasted male smokers and 50 age-matched males who had never smoked (aged 50-59 years). RESULTS: Significantly less alpha-carotene, beta-carotene and beta-cryptoxanthin and vitamin C in plasma of smokers than in never-smokers whereas concentrations of lycopene, lutein/zeaxanthin, phytofluene and vitamin E were similar between the groups. CONCLUSION: Whether lower carotenoid and vitamin C concentrations in smokers than never-smokers reflect different dietary patterns or increased metabolic turnover is unclear but smokers may benefit from increased carotenoid and vitamin C intakes.

Ascorbic Acid↗
PubMed1993

Neuropathies associated with diabetes.

Diabetic neuropathy is the most frequent complication of diabetes and the leading cause of polyneuropathy in the Western world. A distal symmetric predominantly sensory polyneuropathy is the most common of the diverse neuropathies that occur secondary to diabetes. Pain is often the most bothersome and difficult to treat symptom of diabetic neuropathy. Autonomic neuropathy is a frequent feature of diabetic neuropathy and the source of many significant problems including postural hypotension, gastroparesis, diarrhea, constipation, neurogenic bladder, and male impotence. Physicians need to be familiar with the multiple, less common forms of diabetic neuropathy, as these often mimic other medical or neurologic conditions. The cause of diabetic neuropathy is not determined, but abundant evidence suggests that both metabolic and ischemic nerve injury are likely factors. These should not be considered mutually exclusive causes of diabetic neuropathy as both factors likely operate to different degrees to produce the clinical spectrum of neuropathies that are seen in diabetes. Although no effective treatment exists to cure diabetic neuropathy, improvement is possible with glycemic control and symptomatic therapy.

Blood Glucose↗
PubMed1992

Carcinoma of the male breast.

The natural history and current management of carcinoma of the breast in men is reviewed. Articles published from 1942 to 1992 on the natural history, clinical manifestations, diagnosis, and treatment of carcinoma of the breast in men were identified using CANCERLINE and MEDLINE. Carcinoma of the breast affects approximately 1000 men per year in the United States; 300 men per year will die of metastatic disease. The mean age at diagnosis is 59 years. The causes of breast cancer in men are unknown. The most common clinical manifestation of breast cancer in men is a painless, firm subareolar mass or a mass in the upper outer quadrant of the breast. Diagnosis can be confirmed by fine-needle aspiration or surgical biopsy. Infiltrating ductal carcinoma is the predominant histologic type. Treatment is similar to that of women with breast cancer. Men with axillary nodal metastasis should receive adjuvant systemic combination chemotherapy or tamoxifen, or both, after primary surgical treatment. Because most men with carcinoma of the breast have estrogen- and progesterone-receptor-positive tumors, distant metastatic disease should be treated initially with hormonal therapies. The epidemiology, prognostic factors, survival by stage, pattern of metastasis, and response to treatment in men are similar to those in women with breast carcinoma. The data suggest, however, that breast cancers in men are more likely to respond to hormonal manipulation.

Breast Neoplasms↗
PubMed1992

Inhibition by heparin of Fe(II)-catalysed free-radical peroxidation of linolenic acid.

Heparin, in a concentration-dependent manner, inhibited the generation of conjugated dienes and thiobarbituric acid-positive substances when incubated with Fe2+ and gamma-linolenic acid. In the conjugated diene assay, other glycosaminoglycans, on a molar basis calculated with respect to their respective hydrated disaccharide repeat units, were less effective than heparin. Heparin which had been re-N-sulphonated after removal of both N-sulphonates and O-sulphates, and heparin in which iduronate residues had been reduced to idose residues, were largely unaffected in their activity. Removal of both N-sulphonates and O-sulphates greatly reduced the effectiveness of the heparin. Analysis of the effects of heparin fragments generated by heparinase I treatment of heparin showed that depolymerization decreased the effectiveness of the heparin. It is possible that heparins and related strongly acidic polysaccharides may function as endogenous antioxidants, and that sequestration by them, or harmless oxidation by them, of ions such as Fe2+, contributes to their effectiveness.

Catalysis↗
PubMed1992

The silent period in pure sensory neuronopathy.

"Normal" electromyographic silent periods (SPs), produced by electrical stimulation of digital nerves, were recorded in the voluntarily contracting abductor pollicis brevis (APB) muscle of a patient with pure sensory neuronopathy and absent sensory nerve action potentials (SNAPs). Such findings implicate the smaller, slower conducting fibers in the genesis of the cutaneous silent period. These same fibers may be activated during more proximal stimulation to contribute to the latter portions of the mixed nerve silent period.

Action Potentials↗
PubMed1992

Normal conduction in pathways traversing an asymptomatic multiple sclerosis plaque.

A 31-year-old woman developed right facial myokymia as the initial manifestation of multiple sclerosis (MS). An MRI scan revealed a focal signal abnormality confined to the left dorsolateral pontomedullary region. Brain-stem auditory evoked potentials (BAEPs), somatosensory evoked potentials (SEPs), and blink reflex (BR) failed to show a conduction abnormality through the left brain-stem lesion. Instead, BAEP and BR indicated a conduction defect in the right pons and EMG showed myokymic discharges in right facial muscles. Our findings provide rare documentation of normal conduction through a presumably asymptomatic MS plaque. The abnormal MRI signal likely represents tissue edema, rather than demyelination. This case demonstrates that physical findings in MS patients may correlate better with electrophysiological abnormalities than with MRI abnormalities.

Adult↗
PubMed1992

Complications of nonoperative management of blunt hepatic injuries.

Few, if any, complications have been reported with the nonoperative management of selected hepatic injuries diagnosed by computed tomographic (CT) scan in hemodynamically stable patients. This retrospective study was designed to evaluate complications associated with this form of management. Twenty-six patients (21%) of 128 patients with blunt hepatic injuries were treated nonoperatively over a 3-year period. All patients were hemodynamically stable at the time of admission and had hepatic injuries identified by CT scans of the abdomen. Five patients (19%) developed complications associated with nonoperative therapy. Of these, two patients had minor hepatic injuries (grades 1-2) and three had major (grades 3-5) hepatic injuries. Two patients (one with minor and one with major hepatic injury), developed free intraperitoneal biliary leaks and required operative repair. Three patients (one with minor and two with major hepatic injuries) developed large subcapsular bilomas with resultant hepatic dysfunction. These patients were successfully managed with percutaneous CT-guided drainage. There were no deaths in our study population with nonoperative therapy. The complications of hepatic injuries initially managed by expectant observation were treated operatively or by percutaneous CT-guided drainage. Repeated CT evaluation to follow the progress of liver fracture and the occasional use of hepatobiliary scans for the identification of biliary leaks have proven useful in our experience.

Adolescent↗
PubMed1992

Predictive value of electromyography in diagnosis and prognosis of the hypotonic infant.

To investigate the diagnostic validity of electromyography in the hypotonic infant, 79 children aged 0 to 12 months, seen over a 20-year period, were studied retrospectively. The diagnoses using clinical, muscle biopsy, and laboratory characteristics were: 25 central hypotonia, 20 spinal muscular atrophy, 20 myopathy, four myotonic dystrophy, four benign congenital hypotonia, two congenital muscular dystrophy, two myasthenia gravis, one infantile inflammatory myopathy, and one arthrogryposis multiplex congenita. Using strict criteria, electromyography accurately predicted the final diagnosis in 65% of infants with spinal muscular atrophy and was consistent with the diagnosis in another 25%. In contrast, electromyography accurately predicted the final diagnosis in only 10% of infants with myopathy and was normal in 88% of infants with central hypotonia. In infants with spinal muscular atrophy, there was no difference in the predictive value of electromyography when performed in the newborn compared to older infants. Normal distal nerve conduction velocities in infants with spinal muscular atrophy may predict prognosis, since these infants had a longer survival. Electromyography thus has a high predictive value for infantile spinal muscular atrophy but not for myopathy.

Biopsy↗
PubMed1992

Psychogenic seizures: ictal characteristics and diagnostic pitfalls.

We analyzed ictal features of psychogenic seizures using video-EEG recordings in 47 patients and reviewed the medical records to determine if patients received antiepileptic drug therapy and whether they were treated pharmacologically for status epilepticus. Unresponsive behavior in the absence of motor manifestations was the single most common ictal presentation. Motor characteristics previously considered to distinguish psychogenic seizures (out-of-phase limb movements, side-to-side head movements, pelvic thrusting) were infrequent. Most patients (74%) received anticonvulsants, and six were treated as status epilepticus. Slow, subtle writhing or in-phase limb movements were most likely to be mistaken for status epilepticus. Physicians, assuming that the spells constituted a neurologic emergency, omitted the neurologic examination and chart review and proceeded with aggressive pharmacotherapy based merely on observation.

Adolescent↗
PubMed1991

The silent period produced by electrical stimulation of mixed peripheral nerves.

The electromyographic silent period (SP) produced by electrical stimulation of the median and ulnar nerve, before and after lidocaine block of the ulnar nerve at the elbow, was recorded in the voluntarily contracting abductor pollicis brevis (APB) muscle of 4 normal subjects. Prior to block, stimulation of the corresponding segment in either nerve (e.g., wrist and elbow) elicited SPs with similar end points. With more proximal stimulation, the SPs consistently ended earlier. Following the block, ulnar nerve stimulation below the elbow failed to elicit a SP in any subject, despite a mechanical twitch caused by the antagonistic contraction of adductor pollicis muscle. Ulnar nerve stimulation above the block elicited a SP in all subjects similar to the preblock SP. In all 4 subjects, submaximal median nerve stimulation at the wrist produced an H-reflex, followed by a SP in the absence of the direct M-response. This SP, due to selective activation of sensory fibers, lacked a collision component, but, was otherwise similar to the SP elicited by supramaximal wrist stimulation. These findings indicate that the ascending volley following electrical stimulation of a mixed peripheral nerve produces the SP without apparent contribution from the descending motor volley.

Adult↗