The phospholipid headgroup specificity of an ATP-dependent calcium pump

We have replaced the lipid associated with a purified calcium transport protein with a series of defined synthetic dioleoyl phospholipids in order to determine the effect of phospholipid headgroup structure on the ATPase activity of the protein. At 37 degrees C the zwitterionic phospholipids (dioleoyl phosphatidylcholine and dioleoyl phosphatidylethanolamine) support the highest activity, while a phospholipid with two negative charges (dioleoyl phosphatidic acid) supports an activity which is at least twenty times lower. Dioleoyl phospholipids with a single net negative charge support at intermediate ATPase activity which is not affected by the precise chemical structure of the phospholipid headgroup. The protocol used to determine the phospholipid headgroup specificity of calcium transport protein is novel because it establishes the composition of the lipid in contact with the protein without the need to isolate defined lipid-protein complexes. This allows the lipid specificity to be determined using only very small quantities of test lipids. We also determined the ability of the same phospholipids to support calcium accumulation in reconstituted membranes. Two requirements had to be met. The phospholipid had to support the ATPase activity of the pump protein and it had to form sealed vesicles as determined by electron microscopy. Since a number of phospholipids met those requirements it is clear that in vitro the lipid specificity of the calcium-accumulating system is rather broad.

Kinetics of sodium in rabbit arterial wall: inability of aldosterone to alter extra to intracellular distribution

Transport rate constants (kij) describing the kinetics of Na exchanges in isolated rabbit aorta wall were determined by a previously established method involving the use of 22Na as a tracer and digital computer simulation without recourse to ancillary chemical measurements of extracellular space. A three compartment model consisting of (i) extracellular, (ii) intracellular and (iii) subcellular spaces (compartments) was found to describe adequately the kinetics of 22Na. Normative values for intercompartmental kij and extra to intracellular Na ratio were established. It appears that the Na extracellular space in rabbit arterial wall is larger than that in dog or rat arterial wall. Surprisingly, at variance with several tissues of different species (dog, rat, mouse and human tissues), aldosterone did not influence the extra to intracellular distribution of Na. The findings are interpreted in the light of results obtained previously by other workers using entirely unrelated methodologies and suggest that species difference is an important factor to consider when studying effects of aldosterone on tissue electrolyte distribution in the rabbit.

Metabolism and excretion of 3H-1,25-(OH)2-vitamin D3 in healthy adults

The synthesis of very high specific activity 25-OH-vitamin D3 (78 Ci/mmol) has made possible the study of the metabolism and plasma disappearance of 3H after a single dose of 3H-1,25-(OH)2-D3 in quantities that are only 10-20% of the endogenous plasma pool. We studied seven healthy adults who were given doses of 1,25-(OH)2-D3 ranging from 30-2300 pmol. Plasma disappearance was rapid with only 14 +/- 2% of administered 3H remaining in the plasma pool 4 h after labeling. Plasma metabolite profiles during the first 4 h showed only 1,25-(OH)2-D3. Thereafter, significant amounts of other metabolites were detected. The 6-day cumulative excretion of 3H in urine and feces (virtually all associated with metabolites of 1,25-(OH)2-D3) averaged 16 +/- 3% and 49 +/- 11% of the dose, respectively. Compartmental analysis of the isotope data for two subjects who received the smallest doses of 1,25-(OH)2-D3 indicated that endogenous renal 1,25-(OH)2-D3 synthesis rates approximate 0.8-2.4 nmol/day (0.3-1.0 microgram/day).

Giant-cell lesions of the facial skeleton

Differentiation of brown tumors of primary or secondary hyperparathyroidism, giant-cell reparative granulomas, and the "true" giant-cell tumors requires consideration of the clinical presentation, anatomic location, roentgenographic features, and results of metabolic studies. These lesions are indistinguishable by histologic appearance alone. Of the 32 giant-cell lesions of bone that were treated at UCLA during the preceding 20 years, seven were from the head and neck region. Four giant-cell reparative granulomas were easily accessible and were treated by local excision. The three "true" giant-cell tumors were found to be in inaccessible locations and thus were treated with full course irradiation. This resulted in tumor shrinkage, but it is probably not curative. Tumor type, location, and clinical setting are important in planning treatment of these lesions.

Risks of facial plastic surgery in an otolaryngology program

By reviewing 680 rhinoplasty, facelift, blepharoplasty, otoplasty, and chin implant procedures that were performed during a two-year period by UCLA Head and Neck Surgery (Otolaryngology) residents, we have found that the rate of major and minor complications compares favorably with that rate achieved by physicians in practice who have reported their results in the literature. Three hundred and sixty-eight rhinoplasties resulted in 1.6% major complications, 14.4% in minor complications, and 5.2% in revision surgeries. One hundred fourteen facelifts had 5.3% major complications, and 24.5% had minor complications. One hundred fifty-six blepharoplasties had no major complications, and 7.7% had minor complications; 21 chin implants resulted in no major complications, and 9.5% resulted in minor complications; and 21 bilateral otoplasties had no major complications, and 14.3% had minor complications, with 4.8% revisions.

Structure of vancomycin and its complex with acetyl-D-alanyl-D-alanine

Vancomycin, a broad-spectrum antibiotic, inhibits the growth of cell walls by complex formation with peptides terminating in D-alanyl-D-alanine. The structure of vancomycin was determined by X-ray analysis of the degradation product CDP-I. A model of the complex is proposed based on this study and spectroscopic data.

Laryngeal lupus erythematosus

Two cases with laryngeal manifestations of systemic lupus erythematosus presented demonstrate the value of serial indirect laryngeal photography and results of treatment for the mucosal and serosal effects of the disease.

Systemic lupus erythematosus is an autoimmune collagen vascular disease which produces widespread damage to connective tissue, blood vessels, serosal surfaces and mucous membranes (Rodman et ah, 1973). It is no surprise that with such a widespread disorder the upper airways too may show involvement.Estimates of the number of patients with laryngeal involvement have ranged from one percent by Dubois (1966) to one-third of patients by other authors (Babich and Tranaov, 1970; Minchina et al., 1971).

Systemic lupus erythematosus may cause laryngeal symptoms referrable to an active mucosal, submucosal or serosal process. With acute flares of the disease, mucosal ulceration, edema, and submucosal hematomas may result in hoarseness and throat pain (Scarpelli et al., 1959). One case of epiglottitis caused by increased mucosal swelling has been reported (Toomey et al., 1974). As the disease progresses, late effects of mucosal disease including corditis, mucosal thickening, laryngeal scarring with stenosis and laryngitis with dry, thickened vocal cords may appear (Babich and Tramaov, 1970; Smith and Ferguson, 1976). With serosal involvement, the patient may demonstrate perichrondritis, cricoarytenoid arthritis or actual vocal cord paralysis (Dubois, 1966; Montgomery and Lofgren, 1963).

Histopathologic study of involved mucosa along with cultures of the tissue is not diagnostic of systemic lupus erythematosus but can help to rule out other disorders similar in appearance such as tuberculosis and rhinoscleroma. Klebsiella rhinoscleromata infections particularly can cause a similar early inflammatory mucosal and late scarred picture.

Microscopic sections of mucosa from a patient who died of laryngeal edema secondary to systemic lupus erythematosus appeared similar to mucosa from a patient with subglottic stenosis (Smith and Ferguson, 1976) with an infiltration of histiocytes, lymphocytes, plasma and mast cells.

The following two cases demonstrate the differences in the course of serosal and mucosal airways disease.

The pharmacokinetics of carbamazepine

The time-courses of plasma carbamazepine concentrations were followed in six apparently healthy adult subjects who, at different times, took single oral drug doses of 200, 400, 500, 600, 700, 800 and 900 mg. There were some suggestions of impaired bioavailability of the drug when given in tablet form. The following values were obtained for various pharmacokinetic parameters: kabs = 0.176 +/- 0.209 h-1; k = 0.0203 +/- 0.0055 h-1; T1/2 = 37.5 +/- 13.1 h; VD = 0.825 +/- 0.1041 . KG-1; Clearance = 0.0163 +/- 0.0061 1 . kg-1. The elimination rate constant showed a statistically significant increase with increasing drug dose. This may help explain the clinical observation that the rate of rise of steady state plasma carbamazepine concentrations tends to decrease with dose increase in patients taking carbamazepine alone.

Voice analysis for the measurement of anxiety

A recently developed technique for the acoustical analysis of speech is described. Speech is analysed electronically for the presence or absence of a microtremor having a frequency of about 10 Hz. This tremor is said to be attenuated in states of psychological stress. The paper present data supporting the validity of this as a measure of anxiety, using states of both normal and pathological anxiety. An objective scoring system is proposed to overcome some of the problems of unreliability. A number of practical advantages of the voice technique are described.

Childhood myxomas of the head and neck

Childhood myxomas of the head and neck are rare, benign, locally invasive tumors. They present great difficulties in histological diagnosis and because of their tendency to recur, present great difficulties in treatment. The combination of vital structures in the head and neck and longevity in children places the head and neck surgeon in a difficult position when determining how radical treatment should be. From a review of the literature and our own experience with four cases, the treatment of choice was found to be surgical resection with tissue margins checked by frozen section and modified by consideration of function and cosmetic appearance. Recurrence occurs in approximately one-third of these patients, but careful longterm follow-up will aid in early detection and local re-excision.

Is an early calcium flux necessary to stimulate lymphocytes?

Concentrations of concanavalin A or the calcium ionophore A23187 that are optimal for the transformation of pig or mouse lymphocytes do not normally cause a measurable increase in calcium influx compared with unstimulated cells. If the cells are treated with the mitogens in conditions where a measurable increase in calcium influx occurs, no stimulation of the cells can occur while the flux is maintained. If an early influx of extracellular calcium is necessary for stimulation, then a much smaller increase in the total concentration of cellular calcium than reported previously is sufficient to allow the entry of lymphocytes into the cell cycle.

Laryngeal involvement by systemic lupus erythematosus

Indirect laryngeal photography with the rod laryngeal telescope provided an excellent method of documenting evolution of the laryngeal pathology in two cases of systemic lupus erythematosus. This disease may have mucosal or serosal manifestations in the larynx. Currently, management of mucosal disease includes acute and long-term corticosteroid therapy, and should the airway become compromised by edema or scarring, then tracheostomy and specific laryngeal reconstruction during a quiescent period in the disease is required. The course of serosal involvement, notably cricoarytenoid arthritis, may be followed by observing vocal cord motion sequentially and assessing the degree of throat pain. Oral corticosteroids in maintenance dosages is the accepted modality of treatment, with dosage being boosted for exacerbations.

Annular lipids determine the ATPase activity of a calcium transport protein complexed with dipalmitoyllecithin

Pure complexes of dipalmitoyllecithin (DPL, 16:0) which Ca2+, Mg2+ dependent ATPase from sarcoplasmic reticulum are unusual in retaining significant ATPase activity down to about 30 degrees C, well below the transition temperature of the pure lipid at 41 degrees C. A minimum of about 35 lipid molecules per ATPase is required to maintain maximal ATPase activity, but the complexes are progressively and irreversibly inactivated at lower lipid to protein ratios. Complexes containing more than the minimum lipid requirement show very similar temperature profiles of activity about 30 degrees C over a wide range of lipid to protein ratios, up to 1500:1. Spin-label studies indicate that, at lipid to protein ratios of less than about 30 lipids per ATPase, no DPL phase transition can be detected, but at all higher ratios, a phase transition occurs at about 41 degrees C. In all of these complexes there are breaks in the Arrhenius plots of ATPase activity at 27--32 degrees C and at 37.5--38.5 degrees C. Experiments with perturbing agents, such as cholesterol and benzyl alcohol which have well-defined effects on the DPL phase transition, indicate that these breaks in the Arrhenius plots of ATPase activity cannot be attributed to a depressed and broadened phase transition in the lipids near the protein molecules. These results are interpreted as evidence for a phospholipid annulus of at least 30 lipid molecules with interact directly with the ATPase and cannot undergo a phase transition at 41 degrees C. This structural interaction of the ATPase with the annular DPL molecules has a predominant effect in determining the form of the temperature-activity profiles. However, the perturbation of the DPL phase transition does not extend significantly beyond the annulus since a phase transition which starts at 41 degrees C can be detected as soon as extraannular lipid is present in the complexes. We suggest that it may be a general feature of membrane structure that penetrant membrane proteins interact with their immediate lipid environment so as to cause only a minimal perturbation of the lipid bilayer.

The glucagon receptor of rat liver plasma membrane can couple to adenylate cyclase without activating it

1. Activation of adenylate cyclase in rat liver plasma membranes by fluoride or GMP-P (NH)P yielded linear Arrheniun plots. Activation by glucagon alone, or in combination with either fluoride or GMP-P(NH)P resulted in biphasic Arrhenius plots with a well-defined break at 28.5 +/- 1 degrees C. 2. The competitive glucagon antagonist, des-His-glucagon did not activate the adenylate cyclase but produced biphasic Arrhenius plots in combination with fluoride or GMP-P(NH)P. The break temperatures and activation energies were very similar to those observed with glucagon alone, or in combination with either fluoride or GMP-P(NH)P. 3. It is concluded that although des-His-glucagon is a potent antagonist of glucagon, it nevertheless causes a structural coupling between the receptor and the catalytic unit.

The lipid environment of the glucagon receptor regulates adenylate cyclase activity

1. The lipids composition of rat liver plasma membranes was substantially altered by introducing synthetic phosphatidylcholines into the membrane by the techniques of lipid substitution or lipid fusion. 40-60% of the total lipid pool in the modified membranes consisted of a synthetic phosphatidylcholine. 2. Lipid substitution, using cholate to equilibrate the lipid pools, resulted in the irreversible loss of a major part of the adenylate cyclase activity stimulated by F-, GMP-P(NH)P or glucagon. However, fusion with presonicated vesicles of the synethic phosphatidylcholines causes only small losses in adenylate cyclase activity stimulated by the same ligands. 3. The linear form of the Arrhenius plots of adenylate cyclase activity stimulated by F- or GMP-(NH)P was unaltered in all of the membrane preparations modified by substitution or fusion, with very similar activation energies to those observed with the native membrane. The activity of the enzyme therefore appears to be very insensitive to its lipid environment when stimulated by F- or gmp-p(nh)p. 4. in contrast, the break at 28.5 degrees C in the Arrhenius plot of adenylate cyclase activity stimulated by glucagon in the native membrane, was shifted upwards by dipalmitoyl phosphatidylcholine, downwards by dimyristoyl phosphatidylcholine, and was abolished by dioleoyl phosphatidylcholine. Very similar shifts in the break point were observed for stimulation by glucagon or des-His-glucagon in combination with F- or GMP-P(NH)P. The break temperatures and activation energies for adenylate cyclase activity were the same in complexes prepared with a phosphatidylcholine by fusion or substitution. 5. The breaks in the Arrhenius plots of adenylate cyclase activity are attributed to lipid phase separations which are shifted in the modified membranes according to the transition temperature of the synthetic phosphatidylcholine. Coupling the receptor to the enzyme by glucagon or des-His-glucagon renders the enzyme sensitive to the lipid environment of the receptor. Spin-label experiments support this interpretation and suggest that the lipid phase separation at 28.5 degrees C in the native membrane may only occur in one half of the bilayer.

Myxomas of the head and neck

Myxomas are benign mesenchymal tumors that occur rarely in the head and neck. When they do occur, they are prevalent in the jaws and occur less frequently in the subcutaneous tissues. We report ten new cases and review the clinical, structural, and behavioral characteristics of myxomas arising in various head and neck locations. All ages are affected. The most common initial complaint is the presence of a slow-growing mass. The sarcomas, especially liposarcomas and fibrosarcomas, rank high in the differential diagnosis of myxomas. These tumors are stubborn infiltrators. When a capsule is present, it is usually incomplete and insufficient to contain the tumor. Treatment is by wide surgical excision. The high recurrence rate previously reported is probably due to incomplete excision and is higher when enucleation or curettage are used. Long-term follow-up is mandatory since recurrences may develop several years after treatment.

Inner ear pathologic features following mumps infection. Report of a case in an adult

Temporal bone studies in an adult with a moderately severe, bilateral sensorineural hearing loss revealed bilateral cochlear changes 13 years after mumps infection. The organ of Corti was completely absent in the greater part of the superior horizontal basal limbs, with occasional hair cell loss throughout the rest of the cochlea. The outer sulcus cell area was degenerated. The stria vascularis was normal, as was the tectorial membrane, except for small hyaline droplets. The number of nerve fibers was extremely decreased in the spiral bony lamina of the basal turns. Basophilic material, possibily representing degeneration of otoliths, was present in the saccule and utricle, bilaterally, with small amounts in all of the ampullae. This was considered to be either a possible result of cytotoxic cancerocidal therapy, or an incidental nonspecific change.

Plasma protein binding of carbamazepine

The binding of carbamazepine to the proteins of human plasma has been studied using ultrafiltration techniques. In vitro studies at 37 degrees C showed the relation between concentration of unbound drug and total drug to be linear through the range of total concentration of 5 to 50 mug/ml. The per cent unbound drug increased slightly as concentration increased. There was little difference between the extent of binding at 4 degrees C and 20 degrees C, but more carbamazepine was unbound at 37 degrees C. Under in vitro conditions, 6 other anticonvulsants, and aspirin, were tested individually, each at high therapeutic or toxic concentration, and shown not to displace carbamazepine from plasma proteins to a significant degree. The extent of binding of carbamazepine in vivo was determined in a total of 54 plasma samples collected from treated patients; 26.9 plus or minus SD 9.4 percent of the drug was unbound. In blood samples from 23 of these patients, the red cell concentration of carbamazepine averaged 38.3 plus or minus SD 17.9 percent of the plasma concentration. The effects of hepatic and renal diseases on the carbamazepine binding capacity of plasma proteins were assessed by comparing the binding capacity of plasma from disease persons with that from normal subjects. There was no significant difference in binding capacity between plasma from patients with renal disease and that from normal subjects. However, the plasma from patients with hepatic disease bound a slightly lower percentage of carbamazepine than did normal plasma (p smaller than 0.05). This alteration did not correlate with changes in any of 15 biochemical parameters measured in these patients. The clinical significance of these results is discussed.