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Biomedical subjects

R L Ruff

Publications and source records attributed to R L Ruff.

At least 19 recordsLinked to original sources
PubMed1994

A four-drug pain regimen for head and neck cancers.

Twenty patients with end-stage head and neck cancer, unresponsive to either acetaminophen with codeine or oxycodone hydrochloride, were placed on a four-drug analgesic regimen consisting of methadone hydrochloride, Trilisate or acetaminophen, a tricyclic antidepressant, and, in most cases, hydroxyzine. All drugs could be delivered through a feeding tube, making this regimen appropriate for dysphagic patients. The efficacy of this nonparenteral regimen was assessed by structured pretreatment and posttreatment interviews that addressed pain intensity, activity, and sleep levels. All of the patients showed improvement in their pain levels and 16 of the 20 had a > or = 50% improvement in all of their pain ratings (P < .01) that persisted until death (2 to 10 months later). Excellent results and ease of administration make this regimen a good choice for analgesia in terminal patients.

Acetaminophen↗
PubMed1992

Congenital disorders of neuromuscular transmission.

Pathology underlying congenital forms of myasthenia gravis has been delineated through microscopic and electrophysiologic studies over the past 15 years. Differentiation from the immune-mediated disorder is crucial because therapy appropriate for acquired myasthenia may be harmful to patients with congenital disease.

Action Potentials↗
PubMed1992

Extraocular muscles are spared in advanced Duchenne dystrophy.

Fast-twitch extremity muscle fibers are preferentially affected in Duchenne's and Becker's muscular dystrophy. Since saccades are thought to be mediated by fast-twitch fibers, saccadic velocities would be expected to be decreased in these patients. Using infrared oculography, we found that the peak velocities of saccades in 3 patients with advanced Duchenne's or Becker's muscular dystrophy were normal. Clinical findings in 7 other patients with these forms of dystrophy were normal. This investigation is the first study of ocular motility in Duchenne's and Becker's muscular dystrophy. It demonstrates that extraocular muscle function is preserved and suggests that fast-twitch fibers in extraocular muscles possess properties that protect against degeneration.

Adult↗
PubMed1992

Na+ current densities and voltage dependence in human intercostal muscle fibres.

1. Voltage-clamp Na+ currents (INa) were studied in human intercostal muscle fibres using the loose-patch-clamp technique. 2. The fibres could be divided into two groups based upon the properties of INa. The two groups of fibres were called type 1 and type 2. 3. Both type 1 and type 2 fibres demonstrated fast and slow inactivation of INa. 4. Type 1 fibres had lower INa on the endplate border and extrajunctional membrane than type 2 fibres and required larger membrane depolarizations to inactivate Na+ channels by fast or slow inactivation of INa. 5. Type 2 fibres had a higher ratio of INa at the endplate border compared to extrajunctional membrane than Type 1 fibres. 6. Measurement of membrane capacitance suggested that the increase in INa at the endplate border was due to increased Na+ channel density. 7. Histochemical staining of some fibres suggested that type 1 fibres were slow twitch and type 2 fibres were fast twitch. 8. Differences in the properties of Na+ channels between fast- and slow-twitch fibres may contribute to the ability of fast-twitch fibres to operate at high firing frequencies and slow-twitch fibres to be tonically active.

Electric Stimulation↗
PubMed1992

Na current density at and away from end plates on rat fast- and slow-twitch skeletal muscle fibers.

Na current density and membrane capacitance were studied with the loose patch voltage clamp technique on rat fast- and slow-twitch skeletal muscle fibers at three different regions on the fibers: 1) the end plate border, 2) greater than 200 microns from the end plate (extrajunctional), and 3) on the end plate postsynaptic membrane. Fibers were treated with collagenase to improve visualization of the end plate and to enzymatically remove the nerve terminal. The capacitance of membrane patches was similar on fast- and slow-twitch fibers and patches of membrane on the end plate had twice the capacitance of patches elsewhere. For fast- and slow-twitch fibers, the sizes of the Na current normalized to the area of the patch were as follows: end plate greater than end plate border greater than extrajunctional. For both types of fibers, the amplitudes of the Na current normalized to the capacitance of the membrane patch were as follows: end plate approximately end plate border greater than extrajunctional. At each of the three regions, the Na current densities were larger on fast-twitch fibers and fast-twitch fibers had a larger increase in Na current density at the end plate border compared with extrajunctional membrane.

Animals↗
PubMed1992

Relation of aphemia and agraphia.

A 49-year-old right-handed man presented with a severe impairment of motor speech output aphemia. Initially, he could make grunting sounds, but was otherwise mute. There was no disturbance of comprehension, and he preferred to communicate by writing. Writing was agrammatic with lexical errors and mispellings which improved with the speech disturbance. The writing abnormalities of aphemics emphasize the aphasic nature of this speech abnormality.

Agraphia↗
PubMed1991

Calcium-tension relationships of muscle fibers from patients with periodic paralysis.

Lateral gastrocnemius muscle biopsies from a 26-year-old man with hyperkalemic periodic paralysis and a 23-year-old man with hypokalemic periodic paralysis were studied. Both patients came from families in which older relatives had developed a vacuolar myopathy in association with their periodic paralysis. Muscle fibers were chemically skinned, and individual fibers were studied with a low-compliance strain gauge. The tension generated by fibers was studied in baths with calcium concentrations from 10(-8) mol/L to 2.5 x 10(-5) mol/L. The Ca-tension relationships and maximal tensions (normalized to fiber cross-sectional area) of fast and slow twitch fibers were indistinguishable from those found in fibers from 5 normal subjects. The results reinforce earlier findings which suggested that loss of Ca-induced myofibril contraction was not the cause of paralysis in periodic paralysis.

Adult↗
PubMed1991

Ca-, Sr-tension relationships and contraction velocities of human muscle fibers.

Muscle fibers from the lateral gastrocnemius or intercostal muscles of 7 normal adult males were chemically skinned (sarcolemma disrupted) and isolated fibers were divided into two parts for histochemical determination of fiber type and physiologic studies. The Ca- and Sr-induced tension relationships and maximum contraction velocities were measured. Slow twitch fibers developed tension at lower concentrations of Ca or Sr than fast twitch fibers. The difference between fast and slow twitch fibers was greatest when Sr was the activating cation. Fast and slow twitch fibers was greatest when Sr was the activating cation. Fast and slow twitch fibers generated similar maximum tensions. The contraction velocities of fast twitch fibers were more than two-fold greater than slow twitch fibers. Fast-oxidative-glycolytic (FOG, type IIA) and fast-glycolytic (FG, type IIB) fibers had similar Ca- and Sr-tension relationships and contraction velocities.

Adult↗
PubMed1991

Iodoacetate-induced contracture in rat skeletal muscle: possible role of ADP.

The effects of iodoacetic acid (IAA) and ischemic contraction were studied in rat extensor digitorum longus muscles. Ischemic contraction of IAA-treated muscles produced contracture. The onset of contracture was not associated with a change in sarcolemmal electrical properties or reduction in intracellular [ATP]; however, [creatine phosphate] was reduced by 75% and free [ADP] was increased by 665%. Continued stimulation of IAA-treated fibers resulted in depolarization, loss of membrane excitability, further depletion of creatine phosphate, and reduction in [ATP]. The effects seen in IAA-treated muscle did not appear to result from a direct action of IAA on the surface membrane, contractile proteins, or excitation-contraction coupling. The contractures in IAA-treated muscle may have resulted from increased Ca sensitivity of the contractile proteins, increased myoplasmic [Ca], or both. Both effects may have resulted from increased [ADP]. In addition, the reduced acidification during ischemic contraction of IAA-treated fibers compared with control fibers may have further increased the Ca sensitivity of IAA-treated fibers compared with controls.

Adenosine Diphosphate↗
PubMed1991

Effect of anticholinergic agents upon acquired nystagmus: a double-blind study of trihexyphenidyl and tridihexethyl chloride.

We conducted a randomized, double-blind, crossover trial of two anticholinergic agents--trihexyphenidyl and tridihexethyl chloride (a quaternary anticholinergic that does not cross the blood-brain barrier)--in patients with acquired nystagmus and measured visual acuity and nystagmus before and at the end of 1 month on each medication. Of the 10 patients admitted to the study, only five completed trials of both drugs due to intolerance of medication or intercurrent illness. Of six patients who completed the trial of trihexyphenidyl, only one showed improvement. Of six patients who completed a trial of tridihexethyl chloride, four showed improvement. We conclude that (1) trihexyphenidyl is not a reliable treatment for acquired nystagmus, although occasional patients may benefit; (2) anticholinergic agents may suppress nystagmus by peripheral rather than central mechanisms; and (3) the side effects of anticholinergic agents limit their effectiveness in the treatment of nystagmus.

Adult↗
PubMed1991

Second occurrence of spinal epidural metastases.

We reviewed records of 79 men with spinal epidural metastases diagnosed from July 1984 to July 1989, imaged by myelography or MRI, and treated with radiation therapy. Thirteen men (16%) had second epidural metastases. The mean time between lesions that developed within two vertebral bodies of a prior lesion was 2.8 months, compared with 15.2 months for lesions that were three or more vertebral bodies from a prior lesion. Some secondary spinal metastases occurring soon after the initial metastasis may represent regrowth of tumor at the border of the radiation port, suggesting that larger radiation ports be constructed for patients with lengthy expected survival times.

Aged↗
PubMed1991

Treatment of the elderly patient with headache or trigeminal neuralgia.

The elderly as a whole suffer fewer headaches than the young. For the majority headache will represent a minor annoyance to be endured or treated with any available drug in the medicine chest. For some, migraine headaches or tension-type headaches become entwined with every daily activity. With the advent of modern pharmacology, headache can often be treated successfully. Trigeminal neuralgia is a source of particularly high morbidity among the elderly, but may be treated very satisfactorily with carbamazepine or baclofen. Paroxysmal hemicrania is exquisitely sensitive to indomethacin, while cluster headache patients receive relief from oxygen inhalation, corticosteroids or lithium. Headache may be the signature of the disease which leads to serious morbidity and mortality. The 'sentinel' headache of subarachnoid haemorrhage is evaluated by a physician in 15% of patients who will eventually rupture an intracranial aneurysm. Morning headache with nausea and vomiting may represent increased intracranial pressure caused by a tumour, haematoma or abscess. The elderly patient with a new headache needs emergency evaluation for temporal arteritis and rapid corticosteroid treatment if the diagnosis is confirmed, to prevent blindness. The broad spectrum of headache, at times a benign aggravation, while at others the harbinger of death, makes the careful evaluation of each headache imperative. This article attempts to make the difficult evaluation of head pain a little easier.

Aged↗
PubMed1990

Visualization of isolated trigeminal nerve invasion by lymphoma using gadolinium-enhanced magnetic resonance imaging.

A 50-year-old man with active histiocytic lymphoma for 12 years developed an isolated right trigeminal neuropathy. Initial evaluation with head computed tomography, X-rays of the skull base, bone scan, and cerebrospinal fluid analysis including cytology were normal. Gadolinium-enhanced magnetic resonance imaging (MRI) showed enlargement of the proximal third of the right trigeminal nerve. Gadolinium-enhanced MRI can be useful for the early demonstration of cranial nerve invasion by lymphoma.

Contrast Media↗
PubMed1990

Ca sensitivity and acetylcholine receptor currents of twitch and tonic snake muscle fibers.

Myofibrillar Ca sensitivity and single-channel acetylcholine receptor (AChR) currents were studied in garter snake (Thamnophis sirtalis sirtalis) costocutaneous muscle fibers. Nomarski optics were used to identify tonic and fast- and slow-twitch fibers. Measurements of tension generation were made using chemically skinned fibers. The maximum tensions of the three types of fibers were similar, and the fast- and slow-twitch fibers had similar Ca sensitivities. Compared with twitch fibers, tonic fibers had lower threshold Ca concentrations for tension generation and a larger range of Ca concentrations between threshold and maximum tension. The AChR channels were studied by enzymatically removing the nerve terminals and performing patch-clamp recordings on the exposed postsynaptic membrane. Twitch fibers had only one class of end-plate channel with a conductance of approximately 51 pS. Tonic fibers had two types of synaptic channels. One AChR channel in the tonic fibers resembled the type seen in twitch fibers. The other channel in tonic fibers had a smaller conductance of approximately 33 pS and resembled extrajunctional AChRs on denervated twitch fibers.

Acetylcholine↗
PubMed1989

Epidural metastases in prospectively evaluated veterans with cancer and back pain.

Ninety-five male veterans with cancer and back pain were prospectively evaluated for epidural metastases. The evaluation included vertebral roentgenograms and a myelogram. The most common cancers were lung and prostate. Forty-three percent of the patients had an epidural metastasis, including 73% of the 37 patients with myelopathy and 48% of the 29 patients with radiculopathy. None of the 29 patients who had back pain without radiculopathy or myelopathy had an epidural metastasis. Thirty-seven patients were treated with only radiation therapy and dexamethasone and four also had surgical decompression. Nineteen of the 20 patients who could walk at diagnosis walked after completion of therapy, whereas, only 11 of the 21 patients who were not ambulatory at the time of diagnosis walked after completion of therapy. The probability of surviving 12 months was 73% for patients who could walk after treatment and 9% for nonambulatory patients. Emergency spinal canal imaging is warranted in cancer patients with back pain and signs or symptoms of radiculopathy or myelopathy.

Adult↗
PubMed1989

Calcium sensitivity of fast- and slow-twitch human muscle fibers.

Muscle fibers from the lateral gastrocnemius muscles of five normal adult males were chemically skinned (sarcolemma disrupted) and each fiber was divided into two parts for histochemical determination of fiber type and calcium-induced tension measurements. The calcium concentration associated with half-maximal tension was 2.5 microM for fast-twitch and 1.3-1.4 microM for slow-twitch fibers. Fast-oxidative-glycolytic (type 2A) and fast-glycolytic (type 2B) fibers had similar calcium sensitivities. Maximum tensions (kg/cm2) were 2.24 for fast-twitch and 2.19 for slow-twitch fibers.

Calcium↗