Disseminated tuberculosis, CMV viraemia & haemophagocytic-lymphohistiocystosis syndrome in an adult patient with anti- IFNγ autoantibodies - case report and brief review

We report a case of an adult female with disseminated tuberculosis, cytomegalovirus viraemia and haemophagocytic-lymphohistiocystosis syndrome associated with neutralizing anti- interferon gamma (IFNγ) autoantibodies demonstrated by absent IFNγ stimulated STAT1 phosphorylation in the presence of patient sera. A brief review of immunodeficiency caused by anti-IFNγ autoantibodies is also described.

Determination of Vitamin B12 in Fortified Bovine Milk- Based Infant Formula Powder, Fortified Soya-Based Infant Formula Powder, Vitamin Premix, and Dietary Supplements by Surface Plasmon Resonance: Collaborative Study

A collaborative study was conducted on an inhibition-based protein-binding assay using the Biacore Q™ biosensor instrument and the Biacore Qflex™ Kit Vitamin B12 PI. The samples studied included infant formula, cereals, premixes, vitamin tablets, dietary supplements, and baby food. The collaborative study, which involved 11 laboratories, demonstrated that the assay showed an RSDr of 1.59–27.8 and HorRat values for reproducibility of 0.34–1.89 in samples with levels ranging from ppm to ppb. The assay studied is a label-free protein binding-based assay that uses the principle of surface plasmon resonance (SPR) to measure the interaction between vitamin B12 and a specifc binding protein. A Biacore Q biosensor uses this principle to detect binding directly at the surface of a sensor chip with a hydrophilic gold-dextran surface. The instrument passes a mixture of prepared sample extract and binding protein solution across a covalently immobilized vitamin B12 chip surface, and the response is given as free-binding protein as the mixture binds to the immobilized surface. This technique uses the specifcity and robustness of the protein-ligand interaction to allow minimal sample preparation and a wide range of matrixes to be analyzed rapidly. The reagents and accessories needed to perform this assay are provided as the ready-to-use format “Qflex Kit Vitamin B12 PI.” The method is intended for routine use in the quantitative determination of vitamin B12 (as cyanocobalamin) in a wide range of food products, dietary vitamin supplements, and multivitamin premixes.

Circulating tumour DNA and CT monitoring in patients with untreated diffuse large B-cell lymphoma: a correlative biomarker study

BACKGROUND

Diffuse large-B-cell lymphoma is curable, but when treatment fails, outcome is poor. Although imaging can help to identify patients at risk of treatment failure, they are often imprecise, and radiation exposure is a potential health risk. We aimed to assess whether circulating tumour DNA encoding the clonal immunoglobulin gene sequence could be detected in the serum of patients with diffuse large-B-cell lymphoma and used to predict clinical disease recurrence after frontline treatment.

METHODS

We used next-generation DNA sequencing to retrospectively analyse cell-free circulating tumour DNA in patients assigned to one of three treatment protocols between May 8, 1993, and June 6, 2013. Eligible patients had diffuse large-B-cell lymphoma, no evidence of indolent lymphoma, and were previously untreated. We obtained serial serum samples and concurrent CT scans at specified times during most treatment cycles and up to 5 years of follow-up. VDJ gene segments of the rearranged immunoglobulin receptor genes were amplified and sequenced from pretreatment specimens and serum circulating tumour DNA encoding the VDJ rearrangements was quantitated.

FINDINGS

Tumour clonotypes were identified in pretreatment specimens from 126 patients who were followed up for a median of 11 years (IQR 6·8-14·2). Interim monitoring of circulating tumour DNA at the end of two treatment cycles in 108 patients showed a 5-year time to progression of 41·7% (95% CI 22·2-60·1) in patients with detectable circulating tumour DNA and 80·2% (69·6-87·3) in those without detectable circulating tumour DNA (p<0·0001). Detectable interim circulating tumour DNA had a positive predictive value of 62·5% (95% CI 40·6-81·2) and a negative predictive value of 79·8% (69·6-87·8). Surveillance monitoring of circulating tumour DNA was done in 107 patients who achieved complete remission. A Cox proportional hazards model showed that the hazard ratio for clinical disease progression was 228 (95% CI 51-1022) for patients who developed detectable circulating tumour DNA during surveillance compared with patients with undetectable circulating tumour DNA (p<0·0001). Surveillance circulating tumour DNA had a positive predictive value of 88·2% (95% CI 63·6-98·5) and a negative predictive value of 97·8% (92·2-99·7) and identified risk of recurrence at a median of 3·5 months (range 0-200) before evidence of clinical disease.

INTERPRETATION

Surveillance circulating tumour DNA identifies patients at risk of recurrence before clinical evidence of disease in most patients and results in a reduced disease burden at relapse. Interim circulating tumour DNA is a promising biomarker to identify patients at high risk of treatment failure.

FUNDING

National Cancer Institute and Adaptive Biotechnologies.

Detection of classical Hodgkin lymphoma specific sequence in peripheral blood using a next-generation sequencing approach

We applied a highly sensitive next-generation sequencing method to identify lymphoma-specific immunoglobulin gene segments in classical Hodgkin lymphoma (CHL) at initial diagnosis or recurrence, and assessed the ability of detecting such lymphoma-specific sequences in peripheral blood (PB). Seventeen CHL cases were tested and lymphoma-specific sequences were identified in 12 of the primary tumour biopsies. In 11 of these patients whose paired PB samples were available, tumour-specific clonotypes were detected in PB in eight patients. This data demonstrates the feasibility of detecting circulating tumour-specific sequences, creating an unprecedented opportunity to optimize the future treatment and monitoring strategies for patients with CHL.

Immunoglobulin and T cell receptor gene high-throughput sequencing quantifies minimal residual disease in acute lymphoblastic leukemia and predicts post-transplantation relapse and survival

Minimal residual disease (MRD) quantification is an important predictor of outcome after treatment for acute lymphoblastic leukemia (ALL). Bone marrow ALL burden ≥ 10(-4) after induction predicts subsequent relapse. Likewise, MRD ≥ 10(-4) in bone marrow before initiation of conditioning for allogeneic (allo) hematopoietic cell transplantation (HCT) predicts transplantation failure. Current methods for MRD quantification in ALL are not sufficiently sensitive for use with peripheral blood specimens and have not been broadly implemented in the management of adults with ALL. Consensus-primed immunoglobulin (Ig), T cell receptor (TCR) amplification and high-throughput sequencing (HTS) permit use of a standardized algorithm for all patients and can detect leukemia at 10(-6) or lower. We applied the LymphoSIGHT HTS platform (Sequenta Inc., South San Francisco, CA) to quantification of MRD in 237 samples from 29 adult B cell ALL patients before and after allo-HCT. Using primers for the IGH-VDJ, IGH-DJ, IGK, TCRB, TCRD, and TCRG loci, MRD could be quantified in 93% of patients. Leukemia-associated clonotypes at these loci were identified in 52%, 28%, 10%, 35%, 28%, and 41% of patients, respectively. MRD ≥ 10(-4) before HCT conditioning predicted post-HCT relapse (hazard ratio [HR], 7.7; 95% confidence interval [CI], 2.0 to 30; P = .003). In post-HCT blood samples, MRD ≥10(-6) had 100% positive predictive value for relapse with median lead time of 89 days (HR, 14; 95% CI, 4.7 to 44, P < .0001). The use of HTS-based MRD quantification in adults with ALL offers a standardized approach with sufficient sensitivity to quantify leukemia MRD in peripheral blood. Use of this approach may identify a window for clinical intervention before overt relapse.

Multiple roles of the p75 neurotrophin receptor in the nervous system

The p75 neurotrophin receptor (p75NTR) is a transmembrane protein that binds nerve growth factor (NGF) and has multiple functions in the nervous system where it is expressed widely during the developmental stages of life, although expression decreases dramatically by adulthood. Expression of p75NTR can increase in pathological states related to neural cell death. p75NTR is a member of the tumour necrosis factor (TNF) receptor family and it consists of intracellular, transmembrane and extracellular domains which are different from other TNF receptors. Either by interacting with tropomyosin receptor kinase (Trk) receptors or via the independent binding of neurotrophin, p75NTR can induce neurite outgrowth and cellular survival or cell apoptosis through several complicated signal transduction pathways. Most of these signalling pathways remain to be elucidated. By interacting with different cellular factors, p75NTR can induce neuron growth cone collapse or regrowth. p75NTR is also expressed in a variety of glial populations. The many functions of p75NTR require further study.

Pathologic complete response (pCR) following weekly (wkly) paclitaxel (cremophor or albumin-bound) and carboplatin (TC) ± trastuzumab (H), ± bevacizumab (B) in patients (pts) with doxorubicin/cyclophosphamide-resistant (AC-Res) and AC-sensitive (AC-S) large and inflammatory breast cancer

591

Introduction: Historically, pCR is rare in AC-Res in contrast to AC-S BC except following TCH in HER2+ BC in preliminary analysis (SABCS-2004, #1110). Moreover, robust predictors of pCR are needed. Methods: 106 consecutive BC pts on neoadjuvant studies were treated with GM/G-CSF supported dose-dense AC (except 7**- Table ), 2 cycles if AC-Res and 4 if AC-S. Pts then received 9–12 wkly TC (3 wks on, 1 off) ± 6–8 bi-wkly B if HER2- or +12–16 wkly H if HER2+, followed by surgery. Fisher’s exact test was performed to compare pCR percentages by various characteristics. Results: pCR in breast and lymph nodes in 38 of 84 assessable tumors in the first 82 pts were documented. 67% (56/84) tumors were reduced to ≤5 mm. Overall, no difference in pCR rates were found between AC-S and AC-Res BC, but pCR rates were 2- to 4-fold higher in HER2+, AC-S (79%) and AC-Res (65%) subsets compared to HER2-, AC-S (32%) and AC-Res (16%) subsets. Higher pCR rates were associated with HER2+/hormone receptor- (HR-) > HER2+/HR+, HER2-/HR- (triple-) > HER2-/HR+, and within the HER2+ subset-IHC 3+/FISH+ or unknown > IHC 3+/FISH- or IHC 1–2+/FISH+, and ductal > other histology. No patient had clinical cardiac dysfunction or EF <50, except 1 on AC/TC. 13/106 (12%) progression or death at a median follow-up of 22 months (range 2–46) is mostly due to stage IV and CNS progression. Conclusion: Short course of TCH achieves a high rate of pCR in AC-Res and AC-S, HER2+ BC in contrast to TC ± B in AC-Res and AC-S, HER2- BC. This is the first demonstration of high rate of complete AC resistance reversal across stage II-IV, inflammatory and recurrent HER2+ BC. In vivo response adjusted 2–4 cycles of dose-dense AC limited clinical cardiac toxicity. HER2+ (IHC 3+/FISH+ or unknown), HR- and ductal histology are significant predictors of high pCR. HER2 and HR confer 4 predictive subtypes of BC.

[Table: see text]

No significant financial relationships to disclose.

Development of a Microscale Implantable Neural Interface (MINI) Probe System

Cortical recording devices hold promise for providing augmented control of neuroprostheses and brain-computer interfaces in patients with severe loss of motor function due to injury or disease. This paper reports on the preliminary in vitro and in vivo results of our microscale implantable neural interface (MINI) probe system. The MINI is designed to use proven components and materials with a modular structure to facilitate ongoing improvements as new technologies become available. This device takes advantage of existing, well-characterized Michigan probe technologies and combines them to form a multichannel, multiprobe cortical assembly. To date, rat, rabbit, and non-human primate models have been implanted to test surgical techniques and in vivo functionality of the MINI. Results demonstrate the ability to form a contained hydrostatic environment surrounding the implanted probes for extended periods and the ability of this device to record electrophysiological signals with high SNRs. This is the first step in the realization of a cortically-controlled neuroprosthesis designed for human applications.

Interleukin-21 induces T-cell activation and proinflammatory cytokine secretion in rheumatoid arthritis

Interleukin (IL)-21 is a CD4+ T-cell-derived cytokine, which is involved in innate and adaptive immune response. In this study, we analysed IL-21 receptor (IL-21R) expression in peripheral blood and synovial fluid mononuclear cells, and investigated the role of IL-21 in the induction of proinflammatory cytokine production by peripheral blood T cells (PB-T) and synovial fluid T cells (SF-T) from patients with rheumatoid arthritis (RA). Immunohistochemical staining demonstrated that IL-21R-positive cells were significantly increased in inflamed synovial tissues of RA patients compared with osteoarthritis (OA) and healthy controls. Flow cytometric analysis confirmed that IL-21R was mainly expressed in freshly isolated CD4, CD8, B and NK cells from peripheral blood and synovial fluid, but decreased gradually in T cells 24 h after anti-CD3 stimulation. PB- and SF-T cells from RA patients were more responsive to IL-21 when compared with controls. Importantly, isolated PB- or SF-T cells from RA patients, when stimulated with IL-21 and anti-CD3 MoAb, secreted markedly higher levels of TNF-alpha and IFN-gamma than controls. These data indicate that IL-21R is overexpressed in the inflamed synovial membrane and in peripheral blood or synovial fluid leukocytes of RA patients, and that IL-21 enhances local T-cell activation, proliferation and proinflammatory cytokine secretion. Thus, blockade of IL-21R signalling pathway may have a therapeutic potential in acute RA patients.

Paclitaxel, carboplatin and trastuzumab (TCH) achieves high pathological complete remission rate after in vivo response directed 2–4 cycles of doxorubicin and cyclophosphamide (AC) in breast cancer patients

10583

Background: A pathological complete remission (pCR) predicts improved survival in breast cancer (BC). Treatment with AC followed by concurrent TCH improved pCR rates to 87.5% in Her2 positive 8-patient pilot study (SABCS 2004, abs #1110), confirmed by a subsequent phase II study. We hypothesized that response adjusted AC (2–4 cycles), TCH (3–4 cycles) sequence targets topoisomerase II alpha amplified and deleted clone, respectively (SABCS 2005, abs # 5056). We report here the combined analysis of the Her2 positive (fluorescence in situ hybridization + or immunohistochemistry 3+) subset of these studies. Material and Methods: Thirty-one patients with stage IIB-IV BC were accrued. Twenty-eight of 31 patients received AC in a dose dense manner with GM-CSF support. Patients received carboplatin calculated at AUC of 2 and paclitaxel at 80 mg/m2 for 3 weeks followed by 1 week of rest (1 cycle) for a maximum of 4 cycles. Concurrent trastuzumab 4 mg/kg loading dose, then 2 mg/kg/wk was administered for 12–16 weeks. Results: Twenty-nine of 31(94%, CI, 0.79–1) patients showed a clinical complete or partial response (cCR, or cPR). Nineteen of 27 patients (70%, CI, 0.50–0.86) achieved a pCR at surgery; two additional patients had ≤3 mm residual invasive cancer; and lymph node negativity rate was 73%. Of the 3 additional patients with cCR, 1died (underlying cirrhosis), 1 refused surgery, and 1 awaits surgery. A fourth patient with cPR awaits surgery. Ninety percent of the patients (28/31, CI, 0.74–0.98) are alive, and 77% (24/31, CI, 0.59–0. 90) are progression free at median follow up of 19 months (range 6–35 months). Median ejection fraction by echocardiogram was 60% (range 50–74); no patient had clinical cardiac dysfunction. One patient each on GM-CSF and peg-GCSF developed neutropenic fever. Conclusion: Short course of TCH following response adjusted 2–4 cycles of AC will have an improved therapeutic ratio with minimum cardiac toxicity and maximal response.

[Table: see text]

[Table: see text]

Weekly carboplatin and nab-paclitaxel plus trastuzumab, or plus or minus bevacizumab: Clinical response in patients with breast cancer

10699

Background: We previously reported a high, complete pathological remission rate in the neoadjuvant setting using carboplatin and metronomic paclitaxel plus or minus trastuzumab (TC ± H) following anthracycline therapy in patients with HER2+ and triple negative (ER-, PR- and HER2-) breast cancer, respectively. [SABCS 2004 abstract #1110 & SABCS 2005 # 5056] . We now report the clinical outcome of patients with breast cancer who were treated with carboplatin and a 130-nm, albumin-bound form of paclitaxel (nab-paclitaxel) plus trastuzumab (nab-TCH) in HER2+ patients, or plus or minus bevacizumab (nab-TC ± B) in HER2- patients or trastuzumab-exposed HER2+ patients. Methods: Twelve consecutive patients with performance status of 0–2 were treated in the neoadjuvant or metastatic setting from April 2005 to December 2005. Of the 12 patients, 10 received prior anthracycline therapy, 10 received prior taxane therapy, 4 received prior carboplatin therapy, and 4 received prior trastuzumab therapy. Patients received carboplatin calculated at an area under the concentration-time curve (AUC) of 2 and nab-paclitaxel at 80–100 mg/m2 weekly for 3 weeks followed by 1 week of rest. Either concurrent trastuzumab therapy was administered at 4 mg/kg loading dose, followed by maintenance dose of 2 mg/kg/wk (3 patients) or concurrent bevacizumab therapy was administered at 10mg/kg every 2 weeks (8 patients). One patient received carboplatin and nab-paclitaxel alone. Results: At this point, 9 pts are evaluable. Eight of the first 9 patients achieved a major clinical response (89%, 95% CI: 52%−100%), with 2 of the 8 responders obtaining a documented complete clinical response. Of the 3 remaining patients, 1 had clinical resolution of malignant ascites, 1 had normalization of tumor marker, and 1 had resolution of pain at early follow up. None of the patients had neutropenic fever or grade 3/4 neuropathy or arthralgia. Conclusions: The above combinations (nab-TCH or nab-TC ± B demonstrated promising antitumor activity in patients with breast cancer in the neoadjuvant and metastatic breast cancer. We have initiated a phase II study exploring nab-TCH and nab-TCB (sequenced after doxorubicin and cyclophosphamide) in the neoadjuvant setting.

[Table: see text]

Zero-Filling Interpolation Processing Technique Can Efficiently Suppress Segmental Stenosis Artifact on Small Arteries of Anatomical Phantoms

The purpose of this study was to evaluate the zero-filling interpolation processing (ZIP) technique for contrast-enhanced MR angiography (CE-MRA). Phantoms of arteries were made with different lumen diameters. Gadolinium-enhanced three-dimensional MR angiography was performed on a GE 1.5T scanner. The parameters of FSPGR pulse sequence were: flip angle 30°, TR 6ms, TE 1.4ms, bandwidth 31.25 kHz, slice thickness 1.2 mm, matrix 256×256. The sequence parameters were kept constant for the studies, whereas four selections were chosen: 1) with ZIP1024 and ZIP×4 techniques; 2) only with ZIP1024 technique; 3) only with ZIP×4 technique; 4) without ZIP technique. For image quality evaluation, MR maximum intensity projection (MIP) images were created. Signal-to-noise ratio (SNR) was measured on MIP images. Vessel edge was determined using full width at half maximum (FWHM) for lumen diameter calculation and results were compared with the actual lumen diameter. The distinctness of the vessel edge and the artifacts on the phantoms were compared for all sequences. Three experienced radiologists made consensus evaluation. The FWHM results of lumen measurements for all the sequences with ZIP techniques were more accurate than that of the sequence without ZIP technique in all phantoms, no matter what the size of the artery. The vessel edge with ZIP1024 technique was more distinct. However, the highest average SNR was obtained with the sequence without ZIP technique. The segmental stenosis artifacts on small artery of phantoms were only efficiently suppressed with the ZIP×4 technique. ZIP technique is excellent for CE-MRA to obtain high quality MR angiography. It not only can improve the spatial resolution and the distinctness of the vessel edge on CE-MRA, but can also efficiently suppress segmental stenosis artifact on small arteries of phantoms.

Novel pathway to the growth of diamond on cubic beta-SiC(001)

By carrying out first-principles calculations on diamond-forming processes, we predict a method for the heteroepitaxial growth of diamond on cubic beta-SiC(001). In the method, we used two processes: (i) the preformation of an sp(3)-like surface configuration of beta-SiC(001) by the adsorption of group-V surfactants; (ii) the successive growth of diamond by the segregation of the surfactants onto a surface and the desorption of surface hydrogen. Analyzing the segregation energies, we found that the atomic size effect plays a crucial role in the surfactant-mediated growth of diamond on beta-SiC(001).

Web-based video for real-time monitoring of radiological procedures

A web-based video transmission of images from CT and MRI consoles was implemented in an Intranet environment for real-time monitoring of ongoing procedures. Images captured from the consoles are compressed to video resolution and broadcast through a web server. When called upon, the attending radiologists can view these live images on any computer within the secured Intranet network. With adequate compression, these images can be displayed simultaneously in different locations at a rate of 2 to 5 images/s through a standard local-area network. While the quality of the images was insufficient for diagnostic purposes, our users survey showed that they were suitable for supervising a procedure, positioning the imaging slices, and for routine quality checking before completion of a study. The system was implemented at UCLA to monitor nine CT's and six MRI's distributed in four different buildings. This system significantly improved the radiologists productivity by saving valuable time spent in trips between reading rooms and examination rooms. It also improved patient care and throughput by reducing the time spent waiting for the radiologists to check a study before removing the patient from the scanner.

Reversible paraneoplastic encephalomyelitis associated with a benign ovarian teratoma

BACKGROUND

Paraneoplastic encephalomyelitis (PEM) is a well characterized, and typically irreversible, paraneoplastic syndrome, usually associated with small cell lung cancer or other malignancy. We describe a case of a young woman with a benign ovarian teratoma who presented with a reversible PEM.

CASE REPORT

A 24-year-old woman presented with a three week history of memory impairment, unusual behavior, personality changes, auditory hallucinations, hypersomnolence and binocular biplopia. On admission she was disoriented and inattentive with impaired short term memory. Small doses of lorazepam (1 mg), given for episodic agitation, repeatedly induced multidirectional bilateral nystagmus and a skew deviation, but her neurological examination was otherwise normal. A left-sided pelvic mass was palpable. Brain MRI pre- and post-gadolinium was normal. There was a mild CSF pleocytosis and an EEG showed minimal bilateral background activity irregularities. There were no other laboratory abnormalities. Two weeks after admission, she clinically deteriorated developing central respiratory failure and a flaccid paraplegia. Repeat MRI showed an area of increased T2 weighted signal in the medulla and three similar areas in the spinal cord. Following removal of her tumor, treatment with high dose corticosteroids and intravenous immunoglobulin, she ultimately made a full recovery. Pathology revealed the tumor to be a benign ovarian cystic teratoma.

CONCLUSIONS

This is the first report of a reversible PEM seen in association with a benign tumor, in this case a mature ovarian teratoma. Presumably, an immune response directed against neural clements of the teratoma cross-reacted with normal brain, brainstem and spinal cord antigens to cause neurologic symptoms. Tumor removal was followed by neurologic recovery.

Pilot trial of immunoglobulin versus plasma exchange in patients with Guillain-Barré syndrome

We compared intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) in the treatment of 50 patients with Guillain-Barré syndrome (GBS). Standard outcome measures did not differ for the two groups. Sixty-one percent of the PLEX-treated group and 69% of the IVIG-treated group improved by one disability grade at 1 month. The complication rate was higher in the PLEX-treated group. We conclude that the efficacy of IVIG in the treatment of GBS is comparable with that of PLEX and that it can be used safely, although we had a small number of patients. We did not observe a higher relapse rate with IVIG. The usefulness of combination therapy is unknown at this time.

Isolated suprascapular nerve palsy: a review of nine cases

BACKGROUND

In nine patients, suprascapular nerve palsy followed serious accidents associated with fractures of the cervical vertebrae, clavicle or scapula and after weight lifting, wrestling and a fall on the elbow or shoulder.

METHOD

All patients were examined as to muscle wasting, weakness and shoulder fixation. EMG examination was done in all cases and six patients underwent surgical exploration.

RESULTS

The palsy was incomplete on clinical and EMG examination in all patients. On exploration, scarring, entrapment, tethering or kinking at the suprascapular notch was four and two had post-traumatic neuromas.

CONCLUSIONS

In contrast to published studies, none of our patients presented with shoulder pain, a spontaneous onset nor with involvement limited to the infraspinatus muscle. The differential diagnosis should include C5 root lesion, brachial plexus neuritis, frozen shoulder and tear of the rotator cuff.

The excitability of human corticospinal neurons is depressed by thiopental

BACKGROUND

We tested the effect of thiopental on the excitability of the corticospinal-motoneuron axis in normal human subjects.

METHODS

Magnetic stimulation was used to excite the neurons in the motor cortex which give rise to the fast conducting corticospinal pathway. The characteristics of the composite excitatory post-synaptic potentials (EPSPs) produced in individual spinal motoneurons by cortical stimulation were derived from changes in the firing probability of voluntarily activated motor units of the first dorsal interosseous muscle.

RESULTS

In 5 normal subjects, we found that thiopental, in incremental doses sufficient to sustain drowsiness (total dose 75 to 175 mg), significantly reduced the amplitude of these composite EPSPs.

CONCLUSIONS

Thiopental reduced the facilitation of motoneurons from the cortex most likely by depressing cortical neurons.

Excitability of human motor cortex during hyperventilation and hypercapnia

We tested the hypothesis that the excitability of corticospinal neurons was altered by changes in PCO2. Magnetic stimulation was used to excite the neurons in the human motor cortex that give rise to the fast-conducting corticospinal pathway. The characteristics of the composite excitatory postsynaptic potentials (EPSPs) produced in individual spinal motoneurons by cortical stimulation were derived from changes in the firing probability of voluntarily activated motor units. The amplitudes of these composite EPSPs in response to a constant cortical stimulus were assumed to reflect the excitability of cortical neurons. In 10 healthy subjects, we found no statistically significant changes in the excitability of the cortical neurons during normocapnic conditions (mean end-tidal PCO2 5.1 kPa), during hyperventilation-induced hypocapnia (mean end-tidal PCO2 2.9 kPa), and during hyperoxic hypercapnia induced by a rebreathing technique (mean end-tidal PCO2 6.9 kPa). We conclude that the excitability of corticospinal neurons activated by magnetic stimulation is not significantly affected by changes in PCO2.

Should we still stitch the subcutaneous fat layer? A clinical and ultrasound assessment in 50 hip operations

Wound haematoma is an undesirable complication of surgery. We report a prospective trial to establish whether a subcutaneous fat stitch affects haematoma formation in hip surgery. A series of 50 patients undergoing hip surgery were randomised to have either a fat stitch or no fat stitch during wound closure. The wounds were assessed clinically with a minimum follow-up of 5 weeks. Subcutaneous haematomas were seen more easily with the patient standing. As clinical assessment for haematoma formation may be unreliable, each patient also had an ultrasound scan. Although the incidence of subcutaneous haematoma was slightly higher in the no fat stitch group (36% compared with 24% in the fat stitch group) this difference was not statistically significant (chi 2 test, P < 0.5). There were no significant differences in the incidence of wound infection and healing rate. From our study we also showed that ultrasound examination was twice as sensitive as clinical examination in diagnosing subcutaneous haematomas and that subcutaneous haematomas are common after hip surgery.

Pseudotumor appearance in chronic hepatitis

A pseudotumor appearance of the liver has not been previously described in chronic hepatitis. We reviewed 81 charts with a biopsy diagnosis of "chronic hepatitis" and at least one radiologic liver scan, and found four cases with a pseudotumor appearance. They all had features on radiologic scans suggestive of space-occupying lesions. Histology showed chronic hepatitis in all four. Two were cirrhotic, one due to alcohol and the other due to hepatitis B. The other two patients had chronic active hepatitis with regenerative nodules but only limited fibrosis, one due to hepatitis B, the other probable non-A, non-B. None had any evidence of hepatic malignancy. We conclude that some patients with chronic hepatitis may present with a pseudotumor appearance on radiological scans, due to the presence of regenerative nodules. Space-occupying lesions on liver scans in chronic hepatitis may represent non-neoplastic liver disease.

Recombination between mutants of Phycomyces with abnormal phototropism

Sexual crosses were studied between mutants of Phycomyces blakesleeanus with abnormal phototropism (phenotype mad). Recombination frequencies were determined among five genes madA to madE. No clear evidence was found for linkage between any of the genes. Inconsistent results in crosses involving madC are attributed to nonisogenicity between the particular strains used. One mad strain was discovered to be a double mutant. A new gene, tentatively designated madG, was segregated from a cross involving that strain.