Survival of Patients With Head and Neck Merkel Cell Cancer: Findings From the Pan-Canadian Merkel Cell Cancer Collaborative

Importance

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma. Due to its relatively low incidence and limited prospective trials, current recommendations are guided by historical single-institution retrospective studies.

Objective

To evaluate the overall survival (OS) of patients in Canada with head and neck MCC (HNMCC) according to American Joint Committee on Cancer 8th edition staging and treatment modalities.

Design, Setting, and Participants

A retrospective cohort study of 400 patients with a diagnosis of HNMCC between July 1, 2000, and June 31, 2018, was conducted using the Pan-Canadian Merkel Cell Cancer Collaborative, a multicenter national registry of patients with MCC. Statistical analyses were performed from January to December 2022.

Main Outcomes and Measures

The primary outcome was 5-year OS. Multivariable analysis using a Cox proportional hazards regression model was performed to identify factors associated with survival.

Results

Between 2000 and 2018, 400 patients (234 men [58.5%]; mean [SD] age at diagnosis, 78.4 [10.5] years) with malignant neoplasms found in the face, scalp, neck, ear, eyelid, or lip received a diagnosis of HNMCC. At diagnosis, 188 patients (47.0%) had stage I disease. The most common treatment overall was surgery followed by radiotherapy (161 [40.3%]), although radiotherapy alone was most common for stage IV disease (15 of 23 [52.2%]). Five-year OS was 49.8% (95% CI, 40.7%-58.2%), 39.8% (95% CI, 26.2%-53.1%), 36.2% (95% CI, 25.2%-47.4%), and 18.5% (95% CI, 3.9%-41.5%) for stage I, II, III, and IV disease, respectively, and was highest among patients treated with surgery and radiotherapy (49.9% [95% CI, 39.9%-59.1%]). On multivariable analysis, patients treated with surgery and radiotherapy had greater OS compared with those treated with surgery alone (hazard ratio [HR], 0.76 [95% CI, 0.46-1.25]); however, this was not statistically significant. In comparison, patients who received no treatment had significantly worse OS (HR, 1.93 [95% CI, 1.26-2.96)].

Conclusions and Relevance

In this cohort study of the largest Canada-wide evaluation of HNMCC survival outcomes, stage and treatment modality were associated with survival. Multimodal treatment was associated with greater OS across all disease stages.

Practice patterns for positive sentinel lymph node in head and neck melanoma

BACKGROUND

An international survey was conducted to investigate the preferences for completion lymph node dissection (CLND) in head and neck melanomas.

METHODS

A questionnaire was sent through the American Society of Head & Neck Surgery (AHNS) and Canadian Society of Otolaryngology-Head and Neck Surgery (CSO).

RESULTS

Hundred and forty-nine surgeons completed the survey. Response rate was 6.3% and 9.7% from AHNS and CSO members, respectively. When presented the scenario of a 47-year-old male with a clinical T3bN0 cheek melanoma, with 1/1 positive sentinel lymph node (SLN) with nodal deposit <2 mm, 72 of respondents (48.3%) would perform a CLND. Reasons for CLND included multiples positive SLN (64.1%), size of nodal deposits (54.2%), and perceived lack of compliance to follow-up (54.2%). Surgeons with access to immunotherapy treatment were less likely to recommend CLND (p = 0.025).

CONCLUSIONS

Following SLN biopsy, nearly half of the surveyed head and neck surgeons would recommend CLND, which contrasts with the current melanoma practice patterns in other anatomic locations. However, compared with an earlier study in the literature it does seem that there has been a shift away from completion neck dissection. Further investigation into understanding practice variations is warranted.

Intraoperative Near-infrared Spectroscopy Correlates with Skin Flap Necrosis: A Prospective Cohort Study

BACKGROUND

Skin flap necrosis (SFN) is a morbid complication that is disfiguring, leads to acute and chronic wound issues, often requires further surgery, and can delay adjuvant chemotherapy. Although most surgeons rely on the clinical examination, near-infrared (NIR) spectroscopy can extrapolate tissue oxygenation and may serve as an important tool to assess flap perfusion intraoperatively. This cohort study was undertaken to evaluate the capacity of NIR spectroscopy to detect clinically relevant differences in tissue perfusion intraoperatively.

METHODS

Patients undergoing oncologic resection of breast cancer, sarcomas, and cutaneous tumors requiring flap reconstruction (local, regional, or free) between January 2018 and January 2019 were analyzed in this study. Clinicians were blinded to device tissue oxygen saturation (StO2) measurements taken intraoperatively after closure and at follow-up appointments in the first 30 days. Measurements were categorized as (1) control areas not affected by the procedure, (2) areas at risk, and (3) areas of necrosis. These areas were retrospectively demarcated by 2 blinded assessors on follow-up images and transposed onto anatomically correlated intraoperative StO2 measurements. Mean StO2 values were compared using a single-sample t test and analysis of variance (ANOVA) to determine differences in oxygenation.

RESULTS

Forty-two patients were enrolled, and 51 images were included in the analysis. Oncologic procedures were predominantly breast (22), postextirpative melanoma (13), and sarcoma (3) reconstructions. Flap reconstruction involved 30 regional skin flaps, 3 pedicled flaps, and 3 free flaps. Nine patients (20.9%) and 11 surgical sites developed SFN. Mean intraoperative StO2 measurements for control areas, areas at risk, and areas of SFN were 74.9%, 71.1%, and 58.3%, respectively. Relative to control areas, mean intraoperative StO2 measurements were lower by 17.5% (P = 0.01) in ultimate areas of SFN and in areas at risk by 5.8% (P = 0.003). Relative to areas at risk, mean StO2 measurements from areas of ultimate SFN were lower by 8.3% (P = 0.04).

CONCLUSION

These preliminary data suggest that measuring skin flap tissue oxygenation intraoperatively, with NIR spectroscopy, can differentiate objective variations in perfusion that are associated with clinical outcomes.

A catalyst for transforming health systems and person-centred care: Canadian national position statement on patient-reported outcomes

Background

Patient-reported outcomes (pros) are essential to capture the patient's perspective and to influence care. Although pros and pro measures are known to have many important benefits, they are not consistently being used and there is there no Canadian pros oversight. The Position Statement presented here is the first step toward supporting the implementation of pros in the Canadian health care setting.

Methods

The Canadian pros National Steering Committee drafted position statements, which were submitted for stakeholder feedback before, during, and after the first National Canadian Patient Reported Outcomes (canpros) scientific conference, 14-15 November 2019 in Calgary, Alberta. In addition to the stakeholder feedback cycle, a patient advocate group submitted a section to capture the patient voice.

Results

The canpros Position Statement is an outcome of the 2019 canpros scientific conference, with an oncology focus. The Position Statement is categorized into 6 sections covering 4 theme areas: Patient and Families, Health Policy, Clinical Implementation, and Research. The patient voice perfectly mirrors the recommendations that the experts reached by consensus and provides an overriding impetus for the use of pros in health care.

Conclusions

Although our vision of pros transforming the health care system to be more patient-centred is still aspirational, the Position Statement presented here takes a first step toward providing recommendations in key areas to align Canadian efforts. The Position Statement is directed toward a health policy audience; future iterations will target other audiences, including researchers, clinicians, and patients. Our intent is that future versions will broaden the focus to include chronic diseases beyond cancer.

Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma

BACKGROUND

Sentinel-lymph-node biopsy is associated with increased melanoma-specific survival (i.e., survival until death from melanoma) among patients with node-positive intermediate-thickness melanomas (1.2 to 3.5 mm). The value of completion lymph-node dissection for patients with sentinel-node metastases is not clear.

METHODS

In an international trial, we randomly assigned patients with sentinel-node metastases detected by means of standard pathological assessment or a multimarker molecular assay to immediate completion lymph-node dissection (dissection group) or nodal observation with ultrasonography (observation group). The primary end point was melanoma-specific survival. Secondary end points included disease-free survival and the cumulative rate of nonsentinel-node metastasis.

RESULTS

Immediate completion lymph-node dissection was not associated with increased melanoma-specific survival among 1934 patients with data that could be evaluated in an intention-to-treat analysis or among 1755 patients in the per-protocol analysis. In the per-protocol analysis, the mean (±SE) 3-year rate of melanoma-specific survival was similar in the dissection group and the observation group (86±1.3% and 86±1.2%, respectively; P=0.42 by the log-rank test) at a median follow-up of 43 months. The rate of disease-free survival was slightly higher in the dissection group than in the observation group (68±1.7% and 63±1.7%, respectively; P=0.05 by the log-rank test) at 3 years, based on an increased rate of disease control in the regional nodes at 3 years (92±1.0% vs. 77±1.5%; P<0.001 by the log-rank test); these results must be interpreted with caution. Nonsentinel-node metastases, identified in 11.5% of the patients in the dissection group, were a strong, independent prognostic factor for recurrence (hazard ratio, 1.78; P=0.005). Lymphedema was observed in 24.1% of the patients in the dissection group and in 6.3% of those in the observation group.

CONCLUSIONS

Immediate completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not increase melanoma-specific survival among patients with melanoma and sentinel-node metastases. (Funded by the National Cancer Institute and others; MSLT-II ClinicalTrials.gov number, NCT00297895 .).

WE-G-217A-06: Spatial Accuracy Quantification of an MR System

PURPOSE

To develop a phantom and measurement protocol for quantifying spatial accuracy of an MR imaging system over its entire imaging volume.

METHODS

The measurement protocol is comprised of a phantom, a set of MR sequence parameters for imaging the phantom, and analysis software for calculating spatial errors in the acquired phantom images. The phantom covers the entire imaging volume of the scanner above the patient table. It consists of layers of tooling foam which does not produce any detectable signal on conventional MR images, embedded with a matrix of oil capsules to serve as markers. To account for possible spatial errors in the construction of the phantom, the phantom was imaged with CT to create a gold standard data set. On MR scanners, the phantom is acquired with a 3D FGRE sequence that covers an extended FOV of 61.44 mm and with bandwidth = ±62.5 kHz. Error measurements are performed by detecting markers in the image sets and identifying them based on their known locations on the phantom. The spatial error of a marker is defined as the difference between its locations on the MR and CT image sets.

RESULTS

The phantom was constructed and the measurement protocol was executed on two different MR scanners. Some markers were located in areas of severe field inhomogeneity or gradient nonlinearity, and could not be adequately detected for analysis. Maximum errors over concentric spherical regions were observed by plotting the error of each marker as a function of their distance from isocenter.

CONCLUSION

The proposed phantom and protocol can be an effective tool for verifying the spatial accuracy of an MR system, which in turn can improve the accuracy and confidence of MR guided therapies. Data from this protocol may also be used in the development of advanced distortion correction algorithms. Employed by General Electric Healthcare.

WE-G-217A-07: Increased MR Spatial Accuracy with Improved Gradient Nonlinearity and Magnet Inhomogeneity Correction

PURPOSE

To develop improved distortion correction of MR images based on higher degree spherical harmonic models of the gradient system and the main magnetic field.

METHODS

The induced field gradient along all three axes can be modeled by first order spherical harmonics. These models provide a true encoding of the physical location of a spin to the frequency at which it is detected. Currently on many commercial systems, only the lower 5 degrees of the model are used for gradient nonlinearity correction. While this provides sufficient accuracy for diagnostic imaging, the gradient nonlinearity correction was extended to include all first order harmonics up to the 9th degree to improve the spatial accuracy of the images. Using zeroth degree spherical harmonics up to the 20th order, a model of the main magnetic field was also incorporated into the correction algorithm. Shifts caused by field inhomogeneity were calculated using knowledge of the receiver bandwidth, frequency encode direction, and the magnetic field at any given point. These corrections were applied to images of a 50 cm diameter phantom, acquired with an extended FOV 3D FGRE sequence. Any improvements in spatial accuracy were measured in the resulting images.

RESULTS

Visual improvements in spatial accuracy were observed with both corrections. With standard gradient nonlinearity correction, edges of the phantom were distorted in a wave-like fashion. With accurate models, almost all of the errors at the edges of the phantom were corrected when both gradient and field homogeneity corrections were applied.

CONCLUSION

With accurate models of the gradient and magnetic field, the two greatest system-induced spatial errors can be corrected. This improved spatial accuracy enables the use of widebore MR scanners for therapy planning on large FOV images and guidance of percutaneous devices. Further applications include extended FOV imaging for combined PET-MR systems. All authors are employed by General Electric Healthcare.

Realignment capability of the nCPMG sequence

The nCPMG sequence is based on a particular phase modulation of the refocusing pulse train, and was originally designed for rendering the spin echo amplitude insensitive to the initial magnetization phase. This pulse sequence has the peculiarity of being easily invertible, which enables perfect driven equilibrium experiments, in the absence of relaxation. This magnetization 'realignment' is effective for all three components. Hence the overall operation is transparent. Supporting theory is presented here, together with the first direct experimental proof of the claim. The experiment shows that, with the present stabilization sequence, perfect realignment is indeed made possible for a range of refocusing pulse nutation angles from 130° to 230°.

Time-domain control of ultrahigh-frequency nanomechanical systems

Nanoelectromechanical systems could have applications in fields as diverse as ultrasensitive mass detection and mechanical computation, and can also be used to explore fundamental phenomena such as quantized heat conductance and quantum-limited displacement. Most nanomechanical studies to date have been performed in the frequency domain. However, applications in computation and information storage will require transient excitation and high-speed time-domain operation of nanomechanical systems. Here we show a time-resolved optical approach to the transduction of ultrahigh-frequency nanoelectromechanical systems, and demonstrate that coherent control of nanomechanical oscillation is possible through appropriate pulse programming. A series of cantilevers with resonant frequencies ranging from less than 10 MHz to over 1 GHz are characterized using the same pulse parameters.

Clinical outcome of metastatic melanoma involving the CNS with or without (w/o) intracranial hemorrhage (IHC)

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Background: Melanoma has a high rate of ICH associated with CNS metastasis (mets). There is no data on the clinical outcome of these patients (pts) in the literature. Methods: A retrospective review of 52 pts with melanoma CNS mets diagnosed from 11/2001 to 09/2006 at our institution. Two pts were excluded due to a second malignancy. The clinical, radiological, and pathological characteristics of these pts were reviewed. Results: 39 pts were diagnosed after onset of neurological symptoms and 11 were diagnosed during staging. Of these, 14 (28%) were solitary, 23 (46%) were = 4, and 13 (26%) were multiple brain mets. Mean age at brain mets diagnosis was 55 years (range 24–88). Mean follow-up was 25 months (mos) (range 3–61) and 64% were male. ICH was found in 22 pts (44%) with 13 pts (26%) having frank hemorrhage on cranial CT and/or MRI scan. ICH was less common (9%) in pts with brain mets diagnosed on staging. 11 pts (8 with ICH, 3 w/o ICH) underwent CNS mets resection through craniotomy followed by whole brain radiation (WBRT) and/or stereotactic radiotherapy (STR). 7 pts received best supportive care. The remaining pts received WBRT and/or STR. The median survival (MS) for the entire group from CNS mets diagnosis was 7.6 mos. For pts with ICH, overall MS was 9.6 mos with MS of 21.2 mos for pts who underwent craniotomy vs 2.9 mos for pts w/o craniotomy. One pt refused therapy and later died from frank ICH. For pts w/o ICH, overall MS was 6.0 mos with MS of 21.3 mos for pts who underwent craniotomy vs 4.2 mos for pts w/o craniotomy. Pts who underwent craniotomy followed by WBRT and/or STR fared the best with MS of 21.2 mos. Of these, 2 pts with solitary brain mets (1 with ICH, 1 w/o ICH) were alive with no relapse at 58 and 53 mos respectively. The cause of death was disease progression in almost all pts and 85% of pts died from CNS disease progression. One pt died from post-operative complications of craniotomy. Conclusions: ICH by itself is not associated with a negative clinical outcome with appropriate clinical management. Aggressive surgical resection followed by radiotherapy in selected pts improves clinical outcome with prolonged survival possible in a minority of pts.

No significant financial relationships to disclose.

Prevalence of hypogonadism in male patients with renal failure

BACKGROUND

Hypogonadism in men may be secondary to renal failure and is well recognised in patients with end-stage renal disease. It is thought to contribute to the sexual dysfunction and osteoporosis experienced by these patients. However, the association between hypogonadism and lesser degrees of renal dysfunction is not well characterised.

METHODS

The gonadal status of 214 male patients (mean age 56 (SD 18) years) attending a renal centre was studied; 62 of them were receiving haemodialysis and 22 continuous ambulatory peritoneal dialysis for end-stage renal disease, whereas 34 patients had functioning renal transplants and 96 patients were in the low-clearance phase. Non-fasting plasma was analysed for testosterone, follicle-stimulating hormone, luteinising hormone, sex hormone-binding globulin, parathyroid hormone and haemoglobin. Creatinine clearance was estimated in patients not on dialysis, and Kt/V and urea reduction ratio were assessed in patients on dialysis. Testosterone concentrations were classified as normal (>14 nmol/l), low-normal (10-14 nmol/l) or low (<10 nmol/l).

RESULTS

56 (26.2%) patients had significantly low testosterone levels and another 65 (30.3%) had low-normal levels. No significant changes were seen in sex hormone-binding globulin or gonadotrophin levels. Gonadal status was not correlated with haemoglobin level, parathyroid hormone level, creatinine clearance, or dialysis duration or adequacy.

CONCLUSION

Over half of patients with renal failure, even in the pre-dialysis phase, have low or low-normal levels of testosterone, which may be a potentially reversible risk factor for osteoporosis and sexual dysfunction. These patients may be candidates for testosterone-replacement therapy, which has been shown to improve bone mineral-density and libido in men with low and low-normal testosterone levels.

Cystadenoma of the liver without mesenchymal stroma in a female following hormonal therapy for acne

BACKGROUND

Liver cystadenomas are relatively rare tumours that can be difficult to diagnose; treatment entails complete surgical extirpation either by either anatomical resection or enucleation.

CASE OUTLINE

A 19-year-old woman presented with acute onset of abdominal pain and was found to have a multilocular giant liver cyst.The cyst was percutaneously drained; CEA and CA 19-9 tumour markers were elevated in this cyst fluid: CEA 96 microg/L, CAI9-9 37 550 kU/L. The cyst was completely enucleated and has not recurred. Pathological examination confirmed a cystadenoma without mesenchymal stroma, and tumour oestrogen and progesterone receptors were negative.

DISCUSSION

This is the fourth report of a liver cystadenoma without mesenchymal stroma in a female and the first to document elevated cyst fluid tumour markers. This case also illustrates the possible relationship between hormonal therapy and tumour growth.

A multireflection cell for enhanced absorbance detection in microchip-based capillary electrophoresis devices

The design, fabrication and testing of a photolithographically fabricated, glass-based multireflection absorbance cell for microfluidic devices, in particular microchip-based capillary electrophoresis (CE) systems is described. A multireflection cell was fabricated lithographically using a three-mask process to pattern aluminum mirrors above and below a flow channel in a chip, with 30 microm diameter optical entrance or exit apertures (one in each mirror) positioned 200 microm apart. Source and detector were positioned on opposite sides, and the metal mirrors were made 1 cm square, to reduce stray light effects. Calibration curves using bromothymol blue (BTB) with a 633 nm source (He:Ne laser) were linear to at least 0.5 absorbance units, with typical r2 values of 0.9997, relative standard deviations in the slopes of +/- 1.3%, and intercepts of zero within experimental error. Effective optical pathlengths of 50-272 microm were achieved, compared to single-pass pathlengths of 10-30 microm, corresponding to sensitivity enhancements (i.e., optical path length increase) of 5 to 10-fold over single-pass devices. Baseline absorbance noise varied within a factor of two in almost all devices, depending only weakly on path length. This device can give much higher absorbance sensitivity, and should be much easier to manufacture than planar, glass-based devices previously reported.

A fast 3D look-locker method for volumetric T1 mapping

We introduce a fast technique, based on the principles of the 2D Look-Locker T1 measurement scheme, to rapidly acquire the data for accurate maps of T1 in three dimensions. The acquisition time has been shortened considerably by segmenting the acquisition of the k(y) phase encode lines. Using this technique, the data for a 256 x 128 x 32 volumetric T1 measurement can be acquired in 7.6 min. T1 measurements made in phantoms with T1s between 200 and 1200 ms had an accuracy of 4% and a reproducibility of 3.5%. Measurements of T1 made in normal brain using the fast 3D sequence corresponded well with inversion-recovery fast spin-echo measurements.

An integrated microfluidics-tandem mass spectrometry system for automated protein analysis

We describe an integrated analytical system consisting of a microfluidics device micromachined using photolithography/etching technology, a panel of computer-controlled high-voltage relays, and an electrospray ionization tandem mass spectrometer. Movement of solvents and samples on the device and off the device to the mass spectrometer was achieved by directed electroosmotic pumping induced by the activation of a suitable constellation of high-voltage relays. The system was used for the sequential automated analysis of protein digests. We demonstrate low femtomole per microliter sensitivity of detection and compatibility of the system with the automated analysis of proteins separated by two-dimensional gel electrophoresis.

Micromachined analytical devices: microchips for semen testing

Micromachined devices (microchips) have been designed and tested for a range of clinically important assays. In this study we compare sperm motility determined using disposable glass microchips and a conventional Makler chamber. The 17 x 14 mm glass microchips contained three etched test structures each comprising either duplicate or quadruplicate analytical microchannels. Semen samples with sperm counts ranging from 21 to 78 million sperm per ml and forward progression scores of from 1+ to 3+ were evaluated and swimming times ranging from 360 s (3.3+ progression) to 770 s (1+,2 forward progression) observed in the microchips. Motility determined by the time taken for sperm to swim to the end of a microchannel (100 microns wide x 40 microns deep x 10 mm long) in the microchip correlated with forward progression of the sperm determined by the conventional Makler chamber method. This study demonstrates the feasibility of microchips for sperm motility testing and suggests that this technique would be applicable to the study of other types of motile cells.

CT of the liver after cryotherapy of hepatic metastases: imaging findings

Cryotherapy is the in situ destruction of abnormal tissue using subzero temperatures (Fig. 1). Recent studies have demonstrated the technical feasibility, safety, and effectiveness of hepatic cryotherapy in the treatment of liver tumors [1, 2]. Such treatment can be precisely focused on the tumor, thereby preserving surrounding normal tissue. In addition, because major vessels with flowing blood are protected from cryoablation, tumors adjacent to these vessels can be treated without sacrificing vasculature. Hepatic cryoablation is therefore particularly suitable for patients who do not qualify for surgical resection because of multiple metastases involving both lobes of the liver, or because of lesions close to major blood vessels. After the procedure, CT during arterioportography is of little value in distinguishing cryolesion from malignant tumor (Fig. 2), and CT with IV contrast enhancement is recommended for follow-up. It is important to distinguish CT findings of successful and unsuccessful treatment, treatment complications such as abscess and cholestasis, and recurrent tumor. The purpose of this essay is to illustrate the findings on CT with IV contrast enhancement in various situations, emphasizing features that are useful in making accurate differential diagnosis.

Fast spin-echo inversion-recovery imaging versus fast T2-weighted spin-echo imaging in bone marrow abnormalities

RATIONALE AND OBJECTIVES

The purpose of this investigation is to compare a fat-suppressed T2-weighted fast spin-echo (FSE) sequence in bone marrow abnormalities with an FSE STIR sequence that recently has become commercially available.

METHODS

Fast spin-echo images (repetition time [TR], 3500-5000 mseconds; echo time [TE], 96-114 mseconds) and FSE STIR images (TR, 3000-5000 mseconds; TE, 32-40 mseconds; inversion time [TI], 140-150 mseconds) were compared quantitatively and qualitatively calculating signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), and lesion conspicuity and using a qualitative scoring system.

RESULTS

Signal-to-noise ratio (mean +/- standard deviation) was 36.4 +/- 19.3 for the FSE and 29.0 +/- 15.9 for the FSE STIR images (P = .002). Contrast-to-noise ratio (mean +/- standard deviation) was 18.7 +/- 14.3 for the FSE and 20.3 +/- 16.0 for the FSE STIR images (P = .45). Lesion conspicuity (mean +/- standard deviation) was 1.7 +/- 1.5 for the FSE and 3.5 +/- 4.0 for the FSE STIR images (P = .025). The most important difference in the qualitative evaluation related to the better signal homogeneity on the FSE STIR images.

CONCLUSIONS

Fast spin-echo STIR images may be preferable to FSE images with fat suppression due to better image homogeneity and lesion conspicuity.

Glycogen detection by in vivo 13C NMR: a comparison of proton decoupling and polarization transfer

The performance of gated proton decoupling and polarization transfer with respect to glycogen detection by 13C NMR was investigated. Experiments were performed on a 1.5-T whole-body scanner using a 13C surface coil in combination with a proton head coil. Spectra were acquired from a glycogen phantom and from the lower leg of a healthy volunteer using proton decoupling and the polarization transfer method SINEPT. The signal strength of the C1 resonance of glycogen was determined and compared to a reference spectrum acquired without any form of sensitivity enhancement. In the phantom experiment both decoupling and SINEPT produced a signal gain of 3.5. Under in vivo conditions, the signal gain was approximately 2.5 for both techniques. We conclude that decoupling and polarization transfer are equivalently useful techniques for glycogen detection.

Effect of hypothyroidism on phosphorus metabolism in muscle and liver: in vivo P-31 MR spectroscopy study

Hypothyroidism is known to affect nearly every organ and organ system of the human body. The goal of the present study was to gain insight into the phosphorus metabolism and bioenergetic function of striated (calf) muscle and liver in patients with hypothyroidism before and after thyroid hormone treatment. With an ISIS (image-selected in vivo spectroscopy) magnetic resonance (MR) technique for volume selection, phosphorus-31 metabolism of the calf muscle in 10 patients and of the liver in seven patients with severe hypothyroidism was studied before and after treatment. In addition, spectra from the calf muscle and liver were obtained in 10 healthy volunteers. Relative to those from the healthy subjects, the P-31 MR spectra from patients with hypothyroidism showed a significantly diminished phosphocreatine/inorganic phosphate ratio (P less than .01). After thyroid hormone substitution therapy, this ratio returned to normal values within several weeks. No statistically significant changes in the spectra of liver tissue could be detected. The results support the theory that hypothyroidism induces a hormone-dependent, fully reversible impairment of the energy metabolism of striated muscle. Changes in liver metabolism observed with biochemical methods are apparently not detectable with state-of-the-art P-31 MR spectroscopy.

The impact of the ISIS experiment order on spatial contamination

When performing volume-localized spectroscopy measurements, the amount of spatial contamination is an important quality criterion. With the ISIS localization technique contamination cannot only arise from the transition regions around the volume of interest, but also from remote regions of the sample. The latter contamination component is a consequence of inhomogeneous excitation pulses, if short repetition times TR are used. Its severity depends both on the order of the eight phase cycling experiments needed for an ISIS measurement, and on the ratio TR/T1. Here it is theoretically discussed from which regions of the sample contamination can arise for a specific phase cycling order. For the worst orders the contaminating regions are almost three times as large as for the optimal orders. The ratio for the effectively measured contamination, however, can be moderated in real experiments, because cancellation effects occur due to the phase distribution of the contaminating signals. 31P phantom experiments clearly demonstrate that contamination is present even if adiabatic excitation pulses are applied and that spatial contamination can be reduced to about a third by an optimal choice of the phase cycling order.

[In vivo 31P-cardiac magnetic resonance spectroscopy: methods and the first clinical results]

31P-magnetic resonance (MR) spectra of the heart can be obtained from well-defined myocardial regions by combined MR imaging and variable selected volumes for spectroscopy. 31P-spectra of 33 volunteers and of 43 patients with dilated and hypertrophic cardiomyopathy and with coronary artery disease were quantified using a curve-fitting routine. To optimize our technique, we recorded unsaturated and partially saturated spectra in several volunteers. Relative peak areas and signal-to-noise ratios showed significant changes with varying pulse repetition times. Saturation factors were applied to correct spectra from volunteers and patients for the effects of partial saturation. Under resting conditions, peak areas of volunteers and patients from the various groups were statistically indistinct.

Capillary and venous blood glucose measurements using a direct glucose-sensing meter

The aim of the study was to evaluate the precision and accuracy of the ExacTech home blood glucose meter when used with either capillary or venous blood and to compare this with a reference whole blood glucose assay. Non-fasting glucose measurements were used since a validation study showed no capillary-venous differences between fasting and post-prandial states. In a cross-sectional study, blood was taken from 182 patients and measured in duplicate on three batches of strips. Altogether we analysed 1089 readings. The regression of the data from capillary blood samples (meter vs reference method) had a correlation coefficient, of 0.93, and a mean bias of 0.2 mmol l-1. The corrected 90% confidence interval was +/- 1.5 mmol l-1 overall, and +/- 0.9 mmol l-1 for readings under 7.0 mmol l-1. Regression of the data from venous blood samples (meter vs reference method) had a correlation coefficient of 0.93 and a slope of x 1.1. The corrected 90% confidence interval was +/- 1.7 mmol l-1. Thus venous blood may be used even though the meter is calibrated for capillary samples but the value must be corrected by dividing by 1.1. Error-grid analysis showed that day-to-day clinical decisions could be made on the basis of ExacTech readings, although a diagnosis of borderline diabetes may not be possible.

Toward fully automatic estimation of in vivo 31P spectra

Fitting a model to an experimental spectrum is a difficult nonlinear estimation problem. The solution presented here is to start an iterative search procedure sufficiently close to the optimal model parameter set. This is achieved by providing tissue-dependent a priori peak information and by a novel correlation method to get good primary estimates of the resonance and phase offset parameters. The resulting estimation procedure is fully automatic and has proven to be robust for 31P data.

A cytotoxic T-lymphocyte clone derived from mice with progressively growing tumors

Tumor-specific T-cell clones were derived from spleen cells of mice bearing a syngeneic PHS-5 tumor (a P815 mastocytoma mutant). Cells were expanded in vitro and characterized and assayed for activity against the relevant tumor in vivo. Clone cells were CD4-, CD8+ T lymphocytes, as determined by fluorescence activated cell sorting analysis and were specifically cytotoxic against P815 tumor cells in vitro, as shown in chromium 51 release assays. These cells require both antigen and interleukin 2 to proliferate; neither alone is sufficient, even with the addition of interleukin 1. In an experimental P815 liver metastasis model, the adoptive transfer of GD11 or GD11.17 clone cells and injection of recombinant interleukin 2 (7500 U intraperitoneally) 3 days after infusion of tumor cells reduced the number of tumor nodules, while the adoptive transfer of lymphokine-activated killer cells was ineffective.

The reaction of acetaldehyde with brain microtubular proteins: formation of stable adducts and inhibition of polymerization

Stable adducts were formed by treatment of bovine brain microtubular proteins (MTP) with acetaldehyde, followed by gel filtration to remove excess acetaldehyde. The extent of stable adduct formation was determined using [14C]acetaldehyde and was correlated with acetaldehyde concentration and reaction time. Significant inhibition of MTP polymerization was observed at adduct concentrations of 0.6 mol acetaldehyde/mol tubulin dimer. The data suggest that repeated exposure of MTP to low concentrations of acetaldehyde, as would occur in the brain and other tissues of alcoholics, may inhibit MTP polymerization with neurological consequences.

Effects of acetaldehyde on polymerization of microtubule proteins

The in vitro effects of ethanol and acetaldehyde on polymerization of calf brain microtubular proteins (MTP) were examined. While ethanol up to 100 mM had no effect on the polymerization of MTP, acetaldehyde above 0.5 mM had an inhibitory effect. This effect was not dependent on the presence of microtubule-associated proteins (MAPs), since acetaldehyde had a similar effect on the polymerization of highly purified tubulin. Electron microscopy revealed that the number and the length of microtubules at equilibrium was reduced by the presence of acetaldehyde. Acetaldehyde raised the critical concentration for tubulin assembly and caused greater inhibition at lower tubulin concentrations. Acetaldehyde augmented the depolymerizing effects of Ca2+ on preassembled microtubules. In addition, acetaldehyde itself caused depolymerization of microtubules but only in the absence of MAPs. Long-term (19.5 h) incubation of MTP with acetaldehyde led to significant loss of polymerization ability which could not be reversed by removal of acetaldehyde. This loss of activity was apparently independent of the observed formation of reducible adducts between acetaldehyde and MTP.