A multicenter evaluation of lipid profiling with a compact analyzer (Miles Clinistat)

We evaluated the Clinistat Analyzer (Miles Inc., Diagnostics Division, Elkhart, IN) for measuring cholesterol, triglycerides, and high-density lipoprotein (HDL) cholesterol at three medical centers. The system, based on multilayer film technology, uses precalibrated, dry film reagent disks. Ten microliters of serum is applied to the dry film reagent disk in the test procedure. For HDL-cholesterol measurement, serum is pretreated by precipitation with phosphotungstic acid and magnesium chloride. Total precision (CVs) of each of the three assays was less than or equal to 5%. The assay ranges were linear and satisfactory for clinical use. Patients' results compared well with established methods. No significant interferences were found with hemolysis, icterus, and lipemia.

The effects of extracellular calcium and epinephrine on cytosolic-free calcium in single rat adipocytes

Changes in cytosolic calcium concentration ([Ca2+]i) in response to extracellular calcium and epinephrine were monitored in individual rat adipocytes by both photon counting and digital imaging techniques utilizing the intracellular fluorescent calcium probes Fura-2 and Indo-1. Adipocytes containing Fura-2 were attached to coverslips and shown to be as hormonally responsive to insulin as adipocytes in suspension [3.5 +/- 0.8 (n = 5) vs. 4.2 +/- 0.6 (n = 8)-fold increase in glucose oxidation over basal in response to 0.7 nM insulin]. Basal [Ca2+]i in single rat adipocytes was found to be 128 +/- 6 nM (n = 100). The addition of either extracellular calcium or epinephrine elicited transient, concentration-dependent increases in [Ca2+]i. Although the characteristics of calcium- and epinephrine-induced calcium transients are generally similar, the peak [Ca2+]i increase over basal is higher in response to calcium vs. epinephrine [37 and 64% (1 and 27 microM epinephrine), vs. 132 and 236% (2 and 4 mM calcium)]. All the cells tested responded to calcium but only 67% responded to epinephrine. Both alpha- and beta-adrenergic agonists were able to increase [Ca2+]i. The epinephrine-induced [Ca2+]i transients appear to be dependent upon extra-cellular calcium. Neither cholera nor pertussis toxin treatments altered basal [Ca2+]i. However, after treatment of adipocytes with either pertussis or cholera toxin, epinephrine stimulated oscillations in [Ca2+]i. Digital imaging revealed that adipocytes demonstrate a high degree of intracellular spatial heterogeneity and intercellular variability in the magnitude of response to both calcium and epinephrine. These studies demonstrate the feasibility of using single rat adipocytes to monitor intracellular free calcium, using both photon counting and digital imaging.

Photoreceptor deactivation and retinal degeneration mediated by a photoreceptor-specific protein kinase C

The protein kinase C (PKC) family of serine-threonine kinases has been implicated in the regulation of a variety of signaling cascades. One member of this family, eye-PKC, is expressed exclusively in the Drosophila visual system. The inaC (inactivation-no-afterpotential C) locus was shown to be the structural gene for eye-PKC. Analysis of the light response from inaC mutants showed that this kinase is required for the deactivation and rapid desensitization of the visual cascade. Light adaptation was also defective in inaC mutant flies. In flies carrying the retinal degeneration mutation rdgB, absence of eye-PKC suppressed photoreceptor cell degeneration. These results indicate that eye-PKC functions in the light-dependent regulation of the phototransduction cascade in Drosophila.

Cervical neurenteric cyst associated with Klippel-Feil syndrome: a case report and review of the literature

A neurenteric cyst of the spine is a rare congenital disorder secondary to alimentary duplication and vertebral malformation. It should, however, be included in the differential diagnosis of an intradural, extramedullary spinal lesion. We present a case of a cervical neurenteric cyst associated with Klippel-Feil syndrome and discuss the clinical, radiologic, histopathologic, immunohistochemical and embryologic characteristics of this disorder.

Cervical paraganglioma with subsequent intracranial and intraspinal metastases. Case report

Paragangliomas, tumors derived from the extra-adrenal paraganglion system, have commonly been found in the retroperitoneum, abdomen, mediastinum, skull base, and neck. Rare intraspinal cases have included involvement of the cauda equina and filum terminale, and a recent case has been reported of thoracic cord paraganglioma with metastasis to the cauda equina. The authors present the case of a patient with a cervical paraganglioma who underwent subtotal resection followed by postoperative irradiation; she subsequently developed multiple intracranial and intraspinal metastases 7 months following the first decompression procedure.

Palmitate stimulates glucose transport in rat adipocytes by a mechanism involving translocation of the insulin sensitive glucose transporter (GLUT4)

In rat adipocytes, palmitate: a) increases basal 2-deoxyglucose transport 129 +/- 27% (p less than 0.02), b) decreases the insulin sensitive glucose transporter (GLUT4) in low density microsomes and increases GLUT4 in plasma membranes and c) increases the activity of the insulin receptor tyrosine kinase. Palmitate-stimulated glucose transport is not additive with the effect of insulin and is not inhibited by the protein kinase C inhibitors staurosporine and sphingosine. In rat muscle, palmitate: a) does not affect basal glucose transport in either the soleus or epitrochlearis and b) inhibits insulin-stimulated glucose transport by 28% (p less than 0.005) in soleus but not in epitrochlearis muscle. These studies demonstrate a potentially important differential role for fatty acids in the regulation of glucose transport in different insulin target tissues.

Uses of biotechnology and technology transfer to keep food safe

The era of biology is composed of 1) the definition of molecular laws of biology, 2) the exponential expansion of the data base, and 3) the establishment of the first generation molecular and cellular tool kit; this era is driving the development and commercialization of biotechnological products and processes for agriculture and the food system. These products and processes should have a major impact in maintaining and improving food safety. Several meeting and organizational initiatives on biotechnology and food safety are summarized. Possible roles of biotechnology in areas of food safety involve microbial contaminants, nutritional quality, natural antimetabolites, allergens, toxicants, and synthetic chemical residues. Biotechnology will have an impact on all these areas through both improved ability to measure as well as to modify microbes, animals, and plants used as food. Diagnostics for microbial contaminants and biobased alternatives to synthetic chemicals are most advanced. However, all these biotechnological products and processes for food safety are in very early stages of development and commercialization.

Rapid development of enhanced clearance after high-dose cyclophosphamide

We have studied the disposition of cyclophosphamide, its major cytotoxic metabolite phosphoramide mustard, and the synthetic glucocorticoid dexamethasone in nine patients receiving high-dose cyclophosphamide daily for 2 days before bone marrow transplantation. The total body clearance of cyclophosphamide was observed to increase from 93 +/- 27 ml/min on the first day to 178 +/- 83 ml/min on the second day. This was associated with an increase in the clearance of dexamethasone from 369 +/- 104 ml/min to 526 +/- 123 ml/min. An increased rate of formation of phosphoramide mustard with higher peak concentrations was also seen. Simulation studies show that these changes are most likely the result of an increase in the hepatic metabolism of cyclophosphamide. These results show that high-dose cyclophosphamide causes an increase in its own clearance and that of dexamethasone through an apparent induction of hepatic-metabolizing enzymes detectable 24 hours after initial exposure to cyclophosphamide.

Solitary primary lymphoma of the sciatic nerve: case report

An unusual case of a solitary extranodal primary lymphoma of the sciatic nerve in a patient presenting with sciatica and a left footdrop is described. Magnetic resonance imaging was successful in identifying a fusiform lesion in the sciatic nerve in the left infragluteal region. Surgical exploration and biopsy confirmed this as a B cell lymphoma. An extensive metastatic work-up has not identified other sites of lymphomatous involvement.

Disposition of cyclophosphamide on two consecutive cycles of treatment in patients with ovarian carcinoma

The disposition of cyclophosphamide was determined in 12 women with ovarian carcinoma receiving cyclophosphamide 500 mg/m2, doxorubicin (adriamycin) 50 mg/m2 and cisplatin 50 mg/m2 during their first and second courses of therapy. Plasma samples were obtained over 24 h following the completion of the cyclophosphamide infusion and assayed for cyclophosphamide by high performance liquid chromatography. The mean disposition of cyclophosphamide conformed to a 2-compartment model with a mean terminal half-life of 7.14 h on the first course and 8.77 h on the second course. Mean area under the plasma concentration versus time curve appeared to increase from 248.8 mg.h/l for the initial course to 282.2 mg.h/l on the second. Mean total body clearance was 2.01 l/h/m2 on the first course and 1.77 l/h/m2 on the second. Volume of distribution on the first and second courses were 15.3 l/m2 and 18.1 l/m2, respectively. These results suggested that cyclophosphamide clearance decreased when given in a bolus fashion every 3 weeks. However, inter-patient and intra-patient variability was large and the differences in the calculated parameters were not statistically significant when the individual patient data was considered. It is concluded that: 1. cyclophosphamide disposition can best be fit by a bi-exponential equation; 2. considerable intra- and interpatient variability in the concentration-time profile will be encountered; 3. cyclophosphamide disposition does not change from the first to the second course. Reasons for the wide variation are proposed.

Acoustic (loudspeaker) facial EMG monitoring: II. Use of evoked EMG activity during acoustic neuroma resection

Facial electromyographic (EMG) activity was continuously monitored via loudspeaker during eleven translabyrinthine and nine suboccipital consecutive unselected acoustic neuroma resections. Ipsilateral facial EMG activity was synchronously recorded on the audio channels of operative videotapes, which were retrospectively reviewed in order to allow detailed evaluation of the potential benefit of various acoustic EMG patterns in the performance of specific aspects of acoustic neuroma resection. The use of evoked facial EMG activity was classified and described. Direct local mechanical (surgical) stimulation and direct electrical stimulation were of benefit in the localization and/or delineation of the facial nerve contour. Burst and train acoustic patterns of EMG activity appeared to indicate surgical trauma to the facial nerve that would not have been appreciated otherwise. Early results of postoperative facial function of monitored patients are presented, and the possible value of burst and train acoustic EMG activity patterns in the intraoperative assessment of facial nerve function is discussed. Acoustic facial EMG monitoring appears to provide a potentially powerful surgical tool for delineation of the facial nerve contour, the ongoing use of which may lead to continued improvement in facial nerve function preservation through modification of dissection strategy.

Comparison of transketolase activity and thiamin pyrophosphate levels in erythrocytes and liver of rainbow trout (Salmo gairdneri) as indicators of thiamin status

Yearling rainbow trout (Salmo gairdneri) were fed a purified diet with and without thiamin supplementation for 30 wk, at which time overt signs of thiamin deficiency appeared in the deficient group. Overt signs of thiamin deficiency were anorexia, darkening and ataxia. Death rapidly followed the development of overt thiamin deficiency. Transketolase activity and thiamin pyrophosphate levels were measured monthly in erythrocyte and liver samples. Significant differences in erythrocyte transketolase activity between fish fed the thiamin-deficient and control diets were measured after 24 wk of feeding. No significant difference in liver transketolase activity was found between trout fed diets with or without thiamin supplementation. Thiamin pyrophosphate levels were significantly lower in erythrocytes and liver of fish fed the thiamin-deficient diet after 16 wk of feeding. Thiamin pyrophosphate levels in erythrocytes and liver were found to be a more sensitive indicator of thiamin status of rainbow trout than erythrocyte or liver transketolase activity.

Analysis of phosphoramide mustard by reversed-phase ion pair high pressure liquid chromatography

The analysis of phosphoramide mustard by reversed-phase ion pair high pressure liquid chromatography using ultraviolet detection is described. The method will enable measurement of serum concentrations of phosphoramide mustard over a period of approximately 24 h after an i.v. dose of 60 mg/kg of cyclophosphamide and requires 0.5 ml of serum or plasma. The between-day precision of the assay at concentrations of 0.34, 2.76, and 6.90 mg/L gave coefficients of variation of 16, 10, and 9%, respectively. The percentage analytical recovery of phosphoramide mustard is 35%. Preliminary results providing pharmacokinetic data on two adults undergoing high-dose cyclophosphamide treatment prior to bone marrow transplant are presented.

Absorption, body distribution, and excretion of dietary zinc by rainbow trout (Salmo gairdneri)

Rainbow trout (Salmo gairdneri) were held in metabolizable energy chambers at Standard Environmental Temperature (15°C) for 72h following a single feeding of a semi-purified test diet containing tracer quantities of a radioisotope of zinc ((65)Zn) and different combinations of dietary calcium level and zinc source. Gill wastes, urine, and feces were separately collected. After 72h, the fish were killed, and samples of the following tissues removed: eyes, skin, muscle, blood, bone, liver, bile, kidney, gill, spleen, stomach, pyloric caeca, intestine, gonad, and remaining carcass. Radioactivity in the tissues and wastes was determined and the body distribution of the ingested zinc was quantified. Approximately 58% of the administered dose of(65)Zn was recovered. Of the recovered dose, 43.2% was present in the gastro-intestinal tract, 27% in the feces, 14% in the gill water, 16% in the body of the fish, and less than 1% in the urine. Of individual tissues, the gill, liver, kidney, and spleen had concentrations of(65)Zn higher than blood, while the remaining tissues had lower concentrations. Body and tissue levels were increased but not significantly by feeding(65)Zn as an amino acid chelate, compared to feeding as inorganic(65)Zn, while dietary calcium level had no effect. The results of this study indicate that the gills play a major role in excretion of dietary zinc, while the urine plays a minor role.

Thoracic spinal canal stenosis

Hypertrophy of the posterior spinal elements leading to compromise of the spinal canal and its neural elements is a well-recognized pathological entity affecting the lumbar or cervical spine. Such stenosis of the thoracic spine in the absence of a generalized rheumatological, metabolic, or orthopedic disorder, or a history of trauma is generally considered to be rare. Over a 2-year period the authors have treated six cases of thoracic myelopathy associated with thoracic canal stenosis. In four patients the deficits developed gradually and painlessly. The three older patients had a clinical profile characterized by complaints of pseudoclaudication, spastic lower limbs, and evidence of posterior column dysfunction. Two patients were younger adults with low thoracic myelopathy associated with local back pain after minor trauma. Both patients also had congenital narrowing of the thoracic spinal canal. Oil and metrizamide contrast myelography in the prone position were of limited value in diagnosing this condition; in fact, myelography may be misleading and result in erroneous diagnosis of thoracic disc protrusion, when the principal problem is dorsal and lateral compression from hypertrophied facets. Magnetic resonance imaging and computerized tomography sector scanning were more useful in the diagnosis of this disorder than was myelography. Thoracic canal stenosis may be more common than is currently recognized and account for a portion of the failures in anterior and lateral decompression of thoracic disc herniations.

Cervical myelopathy: a comparison of magnetic resonance and myelography

Fifty-seven patients with a strong clinical suspicion of cervical myelopathy were studied with body coil magnetic resonance (MR) and conventional myelography or CT myelography. Eight patients were believed to have normal studies with both modalities. There were six patients with syringomyelia; four with an intramedullary tumor; one with an arteriovenous malformation; 19 with cervical spondylosis at multiple levels; eight with cervical spondylosis at a single level; four with extensive rheumatoid arthritis; four with extradural neoplasm; two with trauma; and one patient with an epidural abscess. In this study, body coil MR was the superior examination for the evaluation of an intramedullary process. It was as diagnostic as myelography in one case of an extramedullary intradural lesion. In patients with extradural disease, body coil MR was the superior study in 45%, equivalent to myelography in 37%, and, although still diagnostic, inferior to myelography in 17%. In 8% of the cases, body coil MR was at best equivocal, whereas myelography was diagnostic. It appears that in technically adequate studies, MR is at least equivalent to myelography in its ability to delineate disease. A superior MR study provides a better appraisal of the size and character of the spinal cord as well as the degree of both anterior and posterior defects on the subarachnoid space and neural structures. In addition, MR is as good as conventional myelography for the identification of extrinsic cervical cord lesions producing cervical myelopathy. Finally, an additional small group of 30 patients were studied with a prototype surface coil to determine its advantages relative to body coil imaging. Each patient had correlative myelography. As with body coil MR, imaging with the surface coil was believed to be more informative than conventional myelography in four patients with intramedullary lesions. The remaining 26 patients suffered from cervical spondylosis. Surface coil MR was believed to be more informative than myelography in six cases (23%), equivalent to myelography in 19 (73%), and less diagnostic than myelography in one (4%). The improved spatial resolution with the use of the surface coil was believed to increase the accuracy of MR.

Nuclear magnetic resonance of the spine: clinical potential and limitation

Magnetic resonance can visualize the vertebral bodies, discs, neural structures, cerebrospinal fluid (CSF), neural foramina, and extradural structures in the sagittal, axial, and coronal planes. The normal nucleus pulposus can be differentiated from the anulus and changes associated with degeneration. Infection, trauma, and neoplastic conditions can be identified. The signal intensity of the CSF relative to extradural and neural structures can be increased to provide evaluation of the size and configuration of the contents of the thecal sac without the use of an intrathecal contrast medium. Impingement by disc, tumors, fracture segments, and expansile masses can then be accurately evaluated. It is the most accurate modality for the evaluation of the foramen magnum, Chiari malformation, syringomyelia, infection, and degeneration of intervertebral discs. It can identify paravertebral soft tissue and bony changes when plain films and computed tomographic (CT) studies are negative or equivocal. Not only can lesions be localized, but significant information regarding the nature of the process can be obtained. Using variations of the spin-echo technique with appropriate T1 and T2-weighted images, magnetic resonance can produce tissue contrast distinctions not possible with CT scans or conventional angiography.

High-performance liquid chromatographic measurement of cyclophosphamide in serum

The analysis of cyclophosphamide [N,N-bis(2-chlorethyl)-tetrahydro-2H-1,3,2-oxazaphosphorin-2-amine -2-oxide] by high-performance liquid chromatography using ultraviolet detection is described. The method will enable measurement of serum concentrations of cyclophosphamide over a period of approximately 24 h after a dose of 150 mg, and requires 1 ml of serum. The between-day precision of the assay at concentrations of 0.3, 1.0, and 15.0 mg/L generated coefficients of variation of 11.8, 12.2, and 7.7%, respectively. Percentages of analytical recovery of cyclophosphamide and internal standard (5-ethyl-5-p-tolylbarbituric acid) were 63 and 73%, respectively. Preliminary data providing the half-life for two patients with normal renal function are presented.

Cytogenetic analysis of a segment of the Y chromosome of Drosophila melanogaster

Males carrying a large deficiency in the long arm of the Y chromosome known to delete the fertility gene kl-2 are sterile and exhibit a complex phenotype: (1) First metaphase chromosomes are irregular in outline and appear sticky; (2) spermatids contain micronuclei; (3) the nebenkerns of the spermatids are nonuniform in size; (4) a high molecular weight protein ordinarily present in sperm is absent; and (5) crystals appear in the nucleus and cytoplasm of spermatocytes and spermatids. In such males that carry Ste+ on their X chromosome the crystals appear long and needle shaped; in Ste males the needles are much shorter and assemble into star-shaped aggregates. The large deficiency may be subdivided into two shorter component deficiencies. The more distal is male sterile and lacks the high molecular weight polypeptide; the more proximal is responsible for the remainder of the phenotype. Ste males carrying the more proximal component deficiency are sterile, but Ste+ males are fertile. Genetic studies of chromosome segregation in such males reveal that (1) both the sex chromosomes and the large autosomes undergo nondisjunction, (2) the fourth chromosomes disjoin regularly, (3) sex chromosome nondisjunction is more frequent in cells in which the second or third chromosomes nondisjoin than in cells in which autosomal disjunction is regular, (4) in doubly exceptional cells, the sex chromosomes tend to segregate to the opposite pole from the autosomes and (5) there is meiotic drive; i.e., reciprocal meiotic products are not recovered with equal frequencies, complements with fewer chromosomes being recovered more frequently than those with more chromosomes. The proximal component deficiency can itself be further subdivided into two smaller component deficiencies, both of which have nearly normal spermatogenic phenotypes as observed in the light microscope. Meiosis in Ste+ males carrying either of these small Y deficiencies is normal; Ste males, however, exhibit low levels of sex chromosome nondisjunction with either deficient Y. The meiotic phenotype is apparently sensitive to the amount of Y chromosome missing and to the Ste constitution of the X chromosome.

Calorimetry of nitrogenase-mediated reductions in detached soybean nodules

Heat evolved by isolated soybean (Glycine max cv Clark) nodules was measured to estimate more directly the metabolic cost associated with the symbiotic N(2) fixation system. A calorimeter constructed by modifying standard laboratory equipment allowed measurement on 1 gram of detached nodules under a controlled gas stream. Simultaneous gas balance and heat output determinations were made.There was major heat output by nodules for all of the nitrogenase substrates tested (H(+), N(2), N(2)O, and C(2)H(2)) further establishing the in vivo energy inefficiency of biological N(2) fixation. Exposure to a short burst of 100% O(2) partially inactivated nitrogenase to permit calculations of heat evolved per mole of substrate reduced. The specific rate of heat evolution for H(+) reductions was 171 +/- 6 kilocalories per mole H(2) evolved in an Ar-O(2) atmosphere, that for N(2) fixation was 784 +/- 26 kilocalories per mole H(2) evolved and N(2) fixed, and that for C(2)H(2) reduction was 250 +/- 12 kilocalories/mole C(2)H(4) formed. When the appropriate thermodynamic parameters are taken into account for the different substrates and products, a DeltaH' of -200 kilocalories per mole 2e(-) is shown to be associated with active transfer of electrons by the nitrogenase system. These values lead to a calculated N(2) fixation cost of 9.5 grams glucose per gram N(2) fixed or 3.8 grams C per gram N(2), which is in close agreement with earlier calculations based on nodular CO(2) production.

Jugular foramen schwannomas

Thirteen patients with schwannomas of the jugular foramen were operated on at the Cleveland Clinic between 1974 and 1983. The authors' experience in managing these rare tumors is presented. Three major growth patterns of jugular foramen schwannoma were seen, and it is postulated that the position of the tumor depends on its point of origin from the nerves as they pass through the pars nervosa of the jugular foramen. The more distal lesions will expand inferiorly out of the base of the skull, and the more proximal lesions will enlarge into the posterior fossa. Tumors in the mid region will tend to expand primarily into bone. The schwannoma was primarily intracranial in six patients. In five patients the tumor expanded the bone at the base of the skull, with only a small intracranial component, and in two patients the tumor was primarily extracranial, with a small extension into the bone or posterior fossa. The presentation of the patients varied according to the tumor growth pattern. Deafness, vertigo, and ataxia were present in all patients with a major intracranial component, and in most of these there were only minimal deficits of the jugular foramen nerves. By contrast, lower cranial nerve involvement, including hoarseness and weakness of the trapezius and sternocleidomastoid muscles, occurred in patients in whom the tumor was primarily, within the bone or extracranial. Three of the five patients with the major component of the schwannoma within the bone also had deafness. Symptomatic history was longest in those with tumor mainly involving the bone at the base of the skull, and shortest in patients with entirely extracranial tumor. Surgical resection was accomplished with a joint neurosurgical-otological approach, usually combining a posterior fossa exploration with either a translabyrinthine transcochlear or infralabyrinthine procedure. The exact nature of the operation depended upon the presence of intracranial tumor and on the extent of bone or extracranial involvement. Total excision was performed in all cases. There was no operative mortality, and surgery resulted in loss of function of the ninth, 10th, and 11th cranial nerves in most patients. The major postoperative morbidity consisted of swallowing difficulties and sputum aspiration.

Experimental determination of the respiration associated with soybean/rhizobium nitrogenase function, nodule maintenance, and total nodule nitrogen fixation

The total metabolic cost of soybean (Glycine max L. Mer Clark) nodule nitrogen fixation was empirically separated into respiration associated with electron flow through nitrogenase and respiration associated with maintenance of nodule function.Rates of CO(2) evolution and H(2) evolution from intact, nodulated root systems under Ar:O(2) atmospheres decreased in parallel when plants were maintained in an extended dark period. While H(2) evolution approached zero after 36 hours of darkness at 22 degrees C, CO(2) evolution rate remained at 38 degrees of the rate measured in light. Of the remaining CO(2) evolution, 62% was estimated to originate from the nodules and represents a measure of nodule maintenance respiration. The nodule maintenance requirement was temperature dependent and was estimated at 79 and 137 micromoles CO(2) (per gram dry weight nodule) per hour at 22 degrees C and 30 degrees C, respectively.The cost of N(2) fixation in terms of CO(2) evolved per electron pair utilized by nitrogenase was estimated from the slope of H(2) evolution rate versus CO(2) evolution rate. The cost was 2 moles CO(2) evolved per mole H(2) evolved and was independent of temperature.In this symbiosis, nodule maintenance consumed 22% of total respiratory energy while the functioning of nitrogenase consumed a further 52%. The remaining respiratory energy was calculated to be associated with ammonia assimilation, transport of reduced N, and H(2) evolution.