Polymerase chain reaction amplification of a measles virus sequence from human temporal bone sections with active otosclerosis

Investigation of a possible viral etiology for otosclerosis was initiated because of the clinical and histopathologic similarities between otosclerosis and Paget's disease of bone and the mounting evidence of a viral etiology in Paget's disease. Thus far, ultrastructural and immunohistochemical studies have revealed measles-like structures and antigens in active otosclerotic lesions. A method for isolation and identification of both DNA and RNA sequences in archival human temporal bone specimens using the polymerase chain reaction technique has been developed. With use of this technique, a 115-base pair sequence of the measles nucleocapsid gene has been identified in 8 of 11 different temporal bone specimens with histologic evidence of otosclerosis. Zero of nine control specimens without histologic evidence of otosclerosis were positive. The association between the presence of the measles nucleocapsid gene sequence and histologic otosclerosis was significant (p < 0.01). This study provides further evidence for a possible measles virus etiology in otosclerosis.

The subtemporal-transpetrous approach for excision of petroclival tumors

The subtemporal transpetrous approach to the petroclival region uses a combination of techniques, including a petrosectomy and a subtemporal and suboccipital craniotomy. Ligation of the greater petrosal sinus, sigmoid sinus, and retraction of the temporal lobe affords wide exposure to the petroclival region and ventral brainstem and minimizes the need for facial nerve translocation. This approach has been successfully used in the management of 10 large tumors of the region, including chondrosarcomas, chordomas, meningiomas, and schwannomas. The history and evolution of this technique and its relation to other similar approaches is discussed.

Case report: renal osteodystrophy in association with spinal stenosis in achondroplasia

A 54 year old woman with achondroplasia presented with symptoms of spinal stenosis. Subsequent studies revealed end-stage renal disease with severe renal osteodystrophy that was characterised by radiographs and new bone biomarkers. We speculate that renal osteodystrophy accentuated spinal stenosis, which is a common feature of achondroplasia in adults.

Delayed facial paralysis after acoustic neuroma surgery: factors influencing recovery

Patients with satisfactory facial nerve function [House-Brackmann (HB) grade I or II] immediately after acoustic neuroma surgery are at risk for delayed facial paralysis. To study this problem, 255 consecutive patients who underwent acoustic neuroma excision with facial nerve preservation were identified. Delayed facial paralysis occurred in 62 (24.3%) patients; 90% ultimately recovered to their initial postoperative HB grade, and 98.3% recovered to within one grade of their initial HB level. Paralysis occurred at an average of 3.65 postoperative days (range, 1-16 days). The average time to maximal recovery for those with changes of 1, 2, 3, and 4 HB grades was 5.6, 21.5, 39.8, and 50.5 weeks, respectively. The early onset of paralysis (< 48 h after surgery) resulted in shorter average recovery times. Of patients who demonstrated nerve deterioration to grades IV-VI, 20 of 38 required tarsorrhaphy or gold-weight placement. We conclude that the over-whelming majority of patients with delayed facial paralysis after acoustic neuroma surgery do eventually recover to their postoperative HB grade. The magnitude and timecourse of delayed facial paralysis are predictive factors for subsequent recovery.

Subchronic intravenous toxicity of the antineoplastic drug, amsacrine, in male Wistar rats

Amsacrine, a DNA intercalator and topoisomerase II inhibitor, is efficacious as an antileukemogenic agent. This study was conducted to assess the subchronic toxicity of amsacrine in rats following a cyclic clinical dosing regimen and as a range-finding experiment for a subsequent carcinogenicity bioassay. Groups of 30 male Wistar rats were administered drug intravenously at doses of 0, 0.25, 1.0, and 3.0 mg/kg daily for 5 days followed by 23 days without treatment. This cycle of dosing and recovery was repeated six times to simulate human clinical usage of the drug. Assessments of hematology, clinical chemistry, and gross and microscopic pathology were conducted 3 and 21 days following completion of dosing in the first, third, and sixth cycles. There were no deaths during the study. Hair loss, diarrhea, tail injuries, chromodacryorrhea, and rhinorrhea were observed primarily in animals administered 3 mg/kg. Hair loss and diarrhea occurred during periods of dosing and generally resolved during the recovery phase of each cycle. Both of these signs became progressively more severe during the latter half of the study. Body weight loss and reduced food consumption also occurred in the 3 mg/kg group during each week of dosing. At study termination, mean body weight and food consumption of the 3 mg/kg group were significantly less than those of controls by approximately 20 and 50%, respectively. Marked, reversible leukopenia associated with reductions in both neutrophil and lymphocyte counts occurred in cycles one and three in animals administered 1 and 3 mg/kg, respectively. Reversible neutropenia was also observed in the 3 mg/kg group in cycle 6. Similar effects on platelet counts were seen in the 3 mg/kg group in all three cycles analyzed. Absolute and relative testes weights of the 3 mg/kg group were significantly less than the vehicle controls at all time points in the third and sixth cycles. Relative testes weights were also decreased in the 1 mg/kg group in cycle 6. Reversible decreases in absolute relative spleen weights occurred in all drug-treated groups in cycle 1 and for the 3 mg/kg group in cycle 3. Lymphoid depletion (spleen, thymus, lymph node), marked hypocellularity of bone marrow, segmental degeneration of seminiferous tubules, and intestinal epithelial cell degeneration were observed at 3 mg/kg. With the exception of testicular changes which remained evident at the end of cycle 6, pathologic lesions were reversible during the 23-day recovery period of each cycle. The results show that the subchronic toxicity of amsacrine is consistent with a cytotoxic mechanism and that target organs are generally tissues with the highest rates of cell turnover. The doses administered in this study induced a range of effects which were minimal at 0.25 mg/kg and dose-limiting at 3 mg/kg and therefore were considered appropriate for use in the subsequent carcinogenicity bioassay.

Bone remodeling indices and secondary hyperparathyroidism in celiac disease

OBJECTIVES

To determine the prevalence of hypovitaminosis D and secondary hyperparathyroidism (SHPT) and to assess bone turnover by using markers of bone formation and resorption in celiac disease (CD).

METHODS

Forty-three patients with CD were investigated: group 1, newly diagnosed celiacs (n = 19); group 2, treated celiacs responding histologically to a gluten-free diet (n = 16); group 3, refractory celiacs, unresponsive to a gluten-free diet and immunosuppressive therapy (n = 8). Serum was drawn for intact parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], ionized calcium (Cai), total alkaline phosphatase (AP), and biochemical markers of bone formation: procollagen I carboxyterminal propeptide (PICP) and osteocalcin (Oc). Urinary indices of bone resorption, deoxypyridinoline (DPD), pyridinoline (PyD), and hydroxyproline (OHP), were measured in a 2-h fasting urine. In 22 patients, computerized tomographic scan for bone mineral density (BMD) was performed.

RESULTS

The prevalence in groups 1, 2, and 3, respectively, of hypovitaminosis D (< 50 nmol/L) was 58%, 25%, and 88%, and the prevalence of SHPT (> 5.4 pmol/L) was 25%, 19%, and 25%. Bone resorption markers were significantly elevated in all groups, and bone formation indices were elevated in the newly diagnosed celiacs compared with a group of healthy adults. Low BMD (T-score greater than -1 SD unit) was found in 68% of patients assessed; 36% of patients had a T-score greater than -2.5 SD units.

CONCLUSIONS

Hypovitaminosis D and SHPT are common in newly diagnosed and refractory celiacs but are less common in those who respond to a gluten-free diet. Newly diagnosed patients have a high bone turnover state with elevation of both bone formation and resorption indices. Those with refractory disease demonstrate a remodeling imbalance with high bone resorption.

An intravascular microdialysis sampling system suitable for application in continuous biochemical monitoring of glucose and lactate

Direct sensor implantation for continuous biochemical monitoring has proved disappointing, but microdialysis sampling devices can serve as a biocompatible patient-sensor interface. We propose a novel "MiniShunt" extracorporeal microdialysis sampling circuit designed to sample core blood, and report the performance of different microdialysis probe membrane types and sizes with pumped and non-pumped blood flow in anaesthetised dogs. Discrete microdialysate and plasma samples collected during glucose and lactate monitoring were analysed with a YSI analyzer and showed microdialysis efficiency (% relative recovery) in excess of 95% for both analytes using fibres of greater than 70 mm2 internal surface area. Pumped veno-venous extracorporeal blood microdialysis sampling of this type could provide a suitable interface for future multi-analyte on-line biosensor applications in critically ill patients.

Tubal and tympanic openings of the peritubal cells: implications for cerebrospinal fluid otorhinorrhea

Cerebrospinal fluid otorhinorrhea after surgery for cerebellopontine angle tumors may persist despite obliteration of the mastoid, middle ear, and tympanic orifice of the eustachian tube. In this study, histologic sections of 120 adult temporal bones were examined by light microscopy to determine the incidence of peritubal pneumatization and to demonstrate the frequency of tubal and tympanic openings of the peritubal cells. The results of this study suggest that the pathway for these persistent cerebrospinal fluid leaks may be via the peritubal cells that open directly into the eustachian tube anterior to its tympanic orifice. Peritubal pneumatization was present in 78 (65%) of the temporal bones. Of the 57 specimens in which the openings of the peritubal cells could be identified, in 52 (91%), the cells opened into the eustachian tube anterior to its tympanic orifice, and in only five (9%), they opened into the middle ear. The overall incidence of tubal openings in this study was 59%. In 13 temporal bones (21%), the tubal opening were at a distance of > 5 mm anterior to the tympanic orifice of the eustachian tube. Therefore, cerebrospinal leak may persist through these tubal openings despite obliteration of the mastoid, middle ear, and tympanic orifice of the eustachian tube. A case of persistent cerebrospinal fluid leak in which extensive peritubal pneumatization was demonstrated by computed tomography scan is presented. Successful control of the leak was obtained only after the tubal openings of these cells several millimeters anterior to the tympanic orifice were obliterated.

Vestibular neurectomy: retrosigmoid-intracanalicular versus retrolabyrinthine approach

Selective vestibular neurectomy is an effective treatment for intractable vertigo of peripheral vestibular origin when preservation of hearing is a goal. The retrolabyrinthine and retrosigmoid-intracanalicular approaches have been used predominantly at our institutions over the last 10 years. The results and complications of these two techniques were compared. No significant differences were found between hearing results in these two patient groups. The retrosigmoid-internal auditory can approach yielded better control of recurrent episodic vertigo, as well as superior ablation of postoperative ice-water caloric responses (p < 0.05). Surgical complications, including the incidence of cerebrospinal fluid leakage (greater in retrolabyrinthine approach) and postoperative headache (more prevalent in retrosigmoid approach), were also analyzed. To further evaluate the results of this study, data were reanalyzed and compared with previously published reports of selective vestibular nerve section.

Effects of fatigue and sprint training on electromechanical delay of knee extensor muscles

Electromechanical delay (EMD) of knee extensors in isometric contraction was investigated in six healthy men before and after four periods of 30-s allout sprint cycling exercise, conducted pre and post a 7-week sprint cycling training programme. The EMD was lengthened from 40.4 (SEM 3.46) ms at rest to 63.4 (SEM 7.80) ms after the fatiguing exercise (P < or = 0.05) in the pre-training test. During maximal voluntary contractions (MVC) conducted after the fatiguing exercise, the peak contraction force (Fpeak) and peak rate of force development (RFDpeak) were reduced by 51%-56% and 38%-50%, respectively (both P < or = 0.05). The mechanisms of EMD lengthening during fatigue could have been due to the deterioration in muscle conductive, contractile or elastic properties and require further study. The training programme increased the total work performed during the four periods of sprint exercise (P < or = 0.05). However, no significant training effects were found in the resting or postexercise EMD, Fpeak and RFDpeak during isometric MVC. These unchanged isometric contraction variables but enhanced dynamic performance suggest that isometric tests of muscle are insensitive to the neuromuscular adaptations to sprint training.

Effects of training on potassium, calcium and hydrogen ion regulation in skeletal muscle and blood during exercise

Ionic regulation is critical to muscle excitation, contraction and metabolism, and thus for muscle function during exercise. This review focuses on the effects of training upon K+, Ca2+ and H+ ion regulation in muscle and K+ regulation in blood during exercise. Training enhances K+ regulation in muscle and blood and reduces muscular fatiguability. Endurance, sprint and strength training in humans induce an increased muscle Na+, K+ pump concentration, usually associated with a reduced rise in plasma [K+] during exercise. Although impaired muscle Ca2+ regulation plays a vital role in fatigue, little is known about possible training effects. In rat fast-twitch muscle, overload-induced hypertrophy and endurance training were associated with reduced sarcoplasmic reticulum Ca2+ uptake, consistent with fast-to-slow fibre transition. In human muscle, endurance and strength training had no effect on muscle Ca2+ ATPase concentration. Whilst muscle Ca2+ uptake, release and Ca2+ ATPase activity were depressed by fatigue, no differences were found between strength athletes and untrained individuals. Muscle H+ accumulation may contribute to fatigue during intense exercise and is also modified by sprint training. Sprint training may increase muscle Lac- and work output with exhaustive exercise, but the rise in muscle [H+] is unchanged or attenuated, indicating a reduced rise in muscle [H+] relative to work performed. Muscle buffering capacity can be dissociated from this improved H+ regulatory capacity after training. Thus, training enhances muscle and blood K+ and muscle H+ regulation during exercise, consistent with improved muscular performance and reduced fatiguability; however, little is known about training effects on muscle Ca2+ regulation during contraction.

The use of the temporoparietal fascial flap in temporal bone reconstruction

After routine canal wall down mastoidectomy, local muscle flaps with and without bone paté, cartilage and fascia are the standard techniques available to otologists wishing to obliterate the mastoid and reconstruct the external auditory canal. Reconstructive options for temporal bone defects after extirpative surgery for cancer, osteoradionecrosis, and revision surgery for chronic granulomatous otitis media, however, are few. Although the neighboring temporoparietal fascia flap (TPFF), based on the superficial temporal vessels, has been frequently employed for auricular reconstruction, its versatility in temporal bone reconstruction has not been widely explored. The TPFF has recently been employed at our institution in 11 patients who presented with a variety of reconstructive problems, including defects after temporal bone resection, surgery for malignant otitis externa, and revision mastoid surgery. Follow-up in these patients ranged from 1 to 43 months (average 18.4 months) and surgical objectives of achieving a dry mastoid bowl, fully epithelialized canal, and/or reduction of mastoid cavity volume was attained in 100% of cases. The TPFF offers many advantages to the otologic surgeon when faced with reconstruction dilemmas that center around a poorly vascularized mastoid cavity and temporal bone. The TPFF is a reliable source of local well-vascularized tissue that is extremely pliable and facilitates both hearing and nonhearing preservation temporal bone reconstruction.

Safety and efficacy of increasing wintertime vitamin D and calcium intake by milk fortification

We studied the safety and efficacy of milk fortified with vitamin D3 and calcium. Over the winter, we conducted a double-blind, placebo-controlled trial of fortified milk (12 micrograms vitamin D3 and 1525 mg calcium per litre) compared to unfortified milk (0.3 micrograms vitamin D3 and 1270 mg calcium per litre) in 102 adults (aged 17-54 years). Serum 25-hydroxyvitamin D [25(OH)D], ionized calcium, and creatinine were measured at baseline and after intervention. Fortification reduced the seasonal decline in serum 25(OH)D concentrations by > 50%. In the fortified group, serum 25(OH)D decreased by 15 nmol/l from 77 +/- 35 nmol/l to 62 +/- 26 nmol/l (p < 0.001). In the control group, serum 25(OH)D fell by 31 nmol/l from 85 +/- 38 nmol/l to 54 +/- 25 nmol/l (p < 0.001). We suggest that milk enriched with vitamin D be provided in high-latitude European countries to diminish the wintertime fall in serum 25(OH)D.

Teflon granuloma presenting as an enlarging, gadolinium enhancing, posterior fossa mass with progressive hearing loss following microvascular decompression

Deleterious effects of Teflon strand placement during microvascular decompression (MVD) for hemifacial spasm are rare. In this report, a patient who had previously undergone suboccipital MVD for hemifacial spasm presented 3 years postoperatively with a progressive asymmetric sensorineural hearing loss and magnetic resonance imaging evidence of an enlarging ipsilateral gadolinium enhancing 1-cm cerebellopontine angle lesion. At surgery a granuloma was found displacing the structures of the internal auditory canal. Histologically, evidence of a Teflon fiber-induced giant cell granuloma was identified. This paper reviews the literature of Teflon-induced histopathology as it relates to posterior fossa MVD surgery, as well as its relation to this previously unreported complication.

The physiological load imposed on basketball players during competition

In this study, the intensities of activity and movement patterns during men's basketball were investigated by videoing the movements and monitoring the heart rate and blood lactate responses of eight elite players during competition. The results are expressed according to 'live time', which is actual playing time, and 'total time', which includes live time as well as all stoppages in play. The mean (+/- S.D.) frequency of all activities was 997 +/- 183, with a change in movement category every 2.0 s. A mean total of 105 +/- 52 high-intensity runs (mean duration 1.7 s) was recorded for each game, resulting in one high-intensity run every 21 s during live time. Sixty percent of live time was spent engaged in low-intensity activity, while 15% was spent in high-intensity activity. The mean heart rate (HR) during live time was 169 +/- 9 beats min-1 (89 +/- 2% peak HR attained during laboratory testing); 75% of live time was spent with a HR response of greater than 85% peak HR. The mean blood lactate concentration was 6.8 +/- 2.8 mM, indicating the involvement of glycolysis in the energy demands of basketball. It is concluded that the physiological requirements of men's basketball are high, placing considerable demands on the cardiovascular and metabolic capacities of players.

Ossiculoplasty with Polymaleinate Ionomeric Prosthesis

With the continued concern over the possible transmission of viral infections through homologous middle ear implants, there is increasing pressure to develop a truly biocompatible alloplastic middle ear prosthesis. The polymaleinate ionomer, which has been used in dentistry as a filling and luting material for more than 15 years, has recently been used to construct total and partial ossicular replacement prostheses. In an attempt to evaluate these new implants, a multicenter prospective clinical trial was initiated. To date, 92 patients have undergone implantation. The follow-up interval ranged from 3 months to 22 months. Although it is premature to discuss the long-term results, the preliminary surgical experience and audio-metric data with these implants are reviewed. From a surgical perspective, the ionomeric prostheses were easily contoured with a diamond burr and were not prone to shattering. Preliminary follow-up audiometric data were available on 80 patients (59 partial ossicular replacement prostheses and 21 total ossicular replacement prostheses). Of the 59 partial ossicular replacement prostheses the air-bone gaps (average of 500 Hz, 1 kHz, 2 kHz and 3 kHz) were as follows: 0 dB to 10 dB, 15 (25%) of 59; 11 dB to 20 dB, 20 (34%) of 59; 21 dB to 30 dB, 11 (19%) of 59; and greater than 30 dB, 13 (22%) of 59. Of the 21 total ossicular replacement prostheses the air-bone gaps were as follows: 0 dB to 10 dB, 6 (29%) of 21; 11 dB to 20 dB, 6 (29%) of 21; 21 dB to 30 dB, 5 (24%) of 21; and greater than 30 dB, 4 (19%) of 21.

Ossiculoplasty with polymaleinate ionomeric prosthesis

With the continued concern over the possible transmission of viral infections through homologous middle ear implants, there is increasing pressure to develop a truly biocompatible alloplastic middle ear prosthesis. The polymaleinate ionomer, which has been used in dentistry as a filling and luting material for more than 15 years, has recently been used to construct total and partial ossicular replacement prostheses. In an attempt to evaluate these new implants, a multicenter prospective clinical trial was initiated. To date, 92 patients have undergone implantation. The follow-up interval ranged from 3 months to 22 months. Although it is premature to discuss the long-term results, the preliminary surgical experience and audiometric data with these implants are reviewed. From a surgical perspective, the ionomeric prostheses were easily contoured with a diamond burr and were not prone to shattering. Preliminary follow-up audiometric data were available on 80 patients (59 partial ossicular replacement prostheses and 21 total ossicular replacement prostheses). Of the 59 partial ossicular replacement prostheses the air-bone gaps (average of 500 Hz, 1 kHz, 2 kHz and 3 kHz) were as follows: 0 dB to 10 dB, 15 (25%) of 59; 11 dB to 20 dB, 20 (34%) of 59; 21 dB to 30 dB, 11 (19%) of 59; and greater than 30 dB, 13 (22%) of 59. Of the 21 total ossicular replacement prostheses the air-bone gaps were as follows: 0 dB to 10 dB, 6 (29%) of 21; 11 dB to 20 dB, 6 (29%) of 21; 21 dB to 30 dB, 5 (24%) of 21; and greater than 30 dB, 4 (19%) of 21.

Early temporalis muscle transposition for the management of facial paralysis

Temporalis muscle transposition is a reliable surgical technique for the reanimation of patients with long-standing facial paralysis. It is often employed when facial nerve reinnervation via crossover or cable grafting is not possible. Temporalis muscle transposition can also be used for the immediate treatment of complete facial paralysis due to insults leaving the facial nerve anatomically intact but requiring a prolonged recovery time (more than 1 year). Because temporalis muscle transposition does not interfere with neuronal regeneration, it may be employed early in the management of complete facial paralysis when recovery is predicted to be extended and incomplete. The authors report their experience with early temporalis muscle transposition in the management of facial paralysis in 56 patients with an anatomically intact facial nerve. More than 90% of these patients achieved improved symmetry at rest as well as purposeful movement at the corner of the mouth. In the last 30 patients, the temporoparietal fascial flap was simultaneously harvested and successfully used to obliterate the donor site defect. In conjunction with the immediate implantation of a gold weight in the ipsilateral upper eyelid, this approach to the early management of facial paralysis helps reduce the period of facial disability from years to weeks in a select group of patients.

Endolymphatic sac tumors: histopathologic confirmation, clinical characterization, and implication in von Hippel-Lindau disease

The term "endolymphatic sac tumor" (ELST) was coined to identify the likely origin of aggressive papillary tumors of the temporal bone. To evaluate the validity of this designation, the temporal bone collection at the Massachusetts Eye and Ear Infirmary was accessed in an effort to determine the pathologic relationship between these tumors and the endolymphatic sac. The search resulted in the identification of a de-novo papillary epithelial lesion arising within the confines of the endolymphatic sac in a patient with von Hippel-Lindau (VHL) disease who harbored a large, destructive ELST in the opposite temporal bone. This finding provides the most substantial evidence to date regarding the origin of the ELST and the accuracy of its nomenclature. Seven additional clinical cases of ELST were identified and analyzed in order to define the natural history of these tumors. All patients had a history of sensorineural hearing loss diagnosed an average of 10.6 years prior to tumor discovery. The presence of a polypoid external auditory canal mass, facial paralysis, and evidence of a destructive mass arising on the posterior fossa surface of the temporal bone were common physical and radiographic findings. The management of these patients, as well as those who are probably prone to such tumors (i.e., VHL patients), is discussed.

Measurement of sarcoplasmic reticulum function in mammalian skeletal muscle: technical aspects

Two recently developed methods for measuring the maximal rate of Ca2+ uptake and Ca2+ ATPase activity (EC 3.1.6.38) in vitro use muscle homogenate rather than isolated sarcoplasmic reticulum (SR). In this study we investigated technical aspects of these assays, including specificity and variability of the assays, the effect of different freezing treatments on maximal Ca2+ uptake and Ca2+ ATPase activity of human and rat muscle homogenate, stability of the homogenate, and the modification of the Ca2+ uptake assay to measure Ag(+)-induced Ca2+ release. Addition of cyclopiazonic acid (20 microM) blocked Ca2+ uptake, demonstrating specificity of the assay. Using frozen muscle homogenate, the inter- and intraassay variation for both assays was less than 9%. Whereas homogenates were stable to freezing for both Ca2+ uptake and Ca2+ ATPase activity, there was a significant (P < 0.05) decrease in activity when muscle was freeze-dried or quickly frozen in small pieces. After 1 h on ice, rat muscle homogenate Ca2+ uptake and Ca2+ ATPase activity had decreased by 6.0% (ns) and 3.6% (P < 0.05), respectively; after 3 h, activity had decreased by 15.3 and 14.7%, respectively (P < 0.01). The Ca2+ uptake assay was modified to allow measurement of Ag(+)-induced Ca2+ release. Following homogenate addition, after the SR vesicles were loaded with Ca2+ and [Ca2+] had declined to a plateau, AgNO3 (141 microM) was added, initiating release of Ca2+ into the assay solution. Addition of dithiothreitol (4 mM) blocked the Ag(+)-induced Ca2+ release, demonstrating specificity of the assay.