Effects of phase aberration on high frame rate imaging

A high frame-rate (HFR) imaging method (about 3750 frames/s for imaging of biological soft tissues at a depth of 200 mm) has been developed recently with limited diffraction beams. This method uses the fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) to construct images, and can be implemented with simple and inexpensive hardware, compared to the conventional delay-and-sum method where a digital beam former is usually used. In this paper, phase aberration effects are studied for both the high frame rate and the conventional methods by adding random phase shifts to echo signals obtained from an experiment. In the study, two broadband linear arrays were used to construct images of an ATS 539 tissue-equivalent phantom that has a frequency-dependent attenuation of about 0.5 dB/MHz/cm. The first array has 48 elements, a central frequency of 2.25 MHz, an aperture of 18.288 mm, and a width of 12.192 mm in elevation. The second has 64 elements, a central frequency of 2.5 MHz, and a dimension of 38.4 mm x 10 mm. The-6dB pulse-echo bandwidth of both arrays is about 40% of their center frequencies. Radiofrequency (RF) signals were digitized at 20 mega samples/s at a 12-bit resolution to construct images. Results show that phase aberration has about the same effect on both methods in terms of image resolution and contrast, although the high frame-rate method can be implemented with a simpler system.

An X wave transform

Limited diffraction beams such as X waves can propagate to an infinite distance without spreading if they are produced with an infinite aperture and energy. In practice, when the aperture and energy are finite, these beams have a large depth of field with only limited diffraction. Because of this property, limited diffraction beams could have applications in medical imaging, tissue characterization, blood flow velocity vector imaging, nondestructive evaluation of materials, communications, and other areas such as optics and electromagnetics. In this paper, a new transform, called X wave transform, is developed. In the transform, any well behaved solutions to the isotropic-homogeneous wave equation or limited diffraction beams can he expanded using X waves as basis functions. The coefficients of the expansions can be calculated with the properties that X waves are orthogonal. Examples are given to demonstrate the efficacy of the X wave transform. The X wave transform reveals an intrinsic relationship between any well behaved solutions to the wave equation and X waves, including limited diffraction beams. This provides a theoretical foundation to develop new limited diffraction beams or solutions to the wave equation that may have practical usefulness.

Folate-targeted enzyme prodrug cancer therapy utilizing penicillin-V amidase and a doxorubicin prodrug

In antibody-targeted enzyme prodrug therapy, a monoclonal antibody (mAb) covalently linked to an enzyme is commonly exploited to concentrate the enzyme on the tumor cell surface prior to administration of a relatively nontoxic prodrug. The tumor-localized enzyme then converts the prodrug into a cytotoxic agent, which in turn diffuses into the tumor causing localized cell death. In this paper, we have substituted folic acid for the mAb as a mean of delivering an attached enzyme, penicillin-V amidase (PVA), to folate receptor (FR)-positive tumor cells. The enzyme PVA is capable of converting a doxorubicin-N-p-hydroxyphenoxyacetamide prodrug (DPO) into its potent parent drug, doxorubicin. For PVA targeting, each PVA molecule was covalently labeled with three molecules of folic acid via the formation of amide bonds. In vitro binding assays showed that folate-PVA-125I conjugates bind specifically to KB cells (FR-positive tumor cells) but not to A549 cells (FR-negative tumor cells). Moreover, in a series of in vitro cytotoxicity tests, folate-PVA conjugates were found to kill folate receptor positive but not receptor negative cells, and when bound to FR-positive cells, folate-PVA conjugates rendered the DPO prodrug as toxic as free doxorubicin (IC50, approximately 0.6 microM). Finally, preliminary in vivo plasma clearance studies in normal mice revealed that i.v. administered folate-PVA-125I and PVA-125I are both cleared from the blood within a 24 h time period, removing concern that nonspecifically trapped folate-PVA might activate prodrug in nontargeted tissues. In view of the fact that only a small number of folate-PVA molecules are required to mediate killing of target cells in vitro, these data argue that folate-targeted enzyme prodrug therapy should be considered for tumor eradication in vivo.

Ethambutol-induced psychosis: a case report

Clinically, ethambutol (EMB)-induced psychosis is rare. In our review of the literature, most cases of antituberculosis agent-associated psychoses were caused by isoniazid (INH). We report the case of a 51-year-old man with suspected tuberculosis (TB) pleurisy. An anti-TB trial with INH, rifampicin and EMB was given initially. Dizziness, disorientation, and auditory and visual hallucinations developed after seven days of therapy. Laboratory examinations, including routine biochemistry tests, serum titer of antinuclear antibodies, cerebrospinal fluid analysis and computerized tomography of the head showed no abnormal findings. Following discontinuation of anti-TB agents, the psychiatric symptoms subsided. When the patient was challenged with EMB, the same psychiatric symptoms recurred, but resolved again after discontinuation of EMB. It is important to be aware that EMB can induce psychosis when anti-TB medications are prescribed.

Na+/Ca2+ exchange current in myocytes isolated from rat hypertrophied heart

Effects of myocardial hypertrophy on the Na+/Ca2+ exchange current in isolated rat cardiac myocytes were investigated, using whole cell patch techniques. Goldblatt 2-kidney, one-clip technique was used to induce cardiomyocyte hypertrophy. The results demonstrated that the Ni(2+)-sensitive Na+/Ca2+ exchange current density was larger in hypertrophied cells than that in normal cells. At a holding potential of mV, the outward current densities were 1.53 +/- 0.31 pA/pF in normal cells and 2.62 +/- 0.53 pA/pF in hypertrophied cells (P < 0.01). At a holding potential of -100 mV, the inward current densities were 0.42 +/- 0.14 pA/pF in normal cells and 1.12 +/- 0.33 pA/pF in hypertrophied cells (P < 0.001). The results suggest that during myocardial hypertrophy the Na+/Ca2+ exchange current is significantly increased.

Seroprevalence of cytotoxin-associated gene A positive Helicobacter pylori strains in Changle, an area with very high prevalence of gastric cancer in south China

BACKGROUND

Helicobacter pylori, especially the CagA-positive strains, are closely associated with peptic ulcers and gastric cancers. We performed a large scale gastric cancer screening project and examined the prevalence of H. pylori and CagA-positive strains in Changle, China, an area with one of the World's highest gastric cancer mortality. We also compared the prevalence with that in Hong Kong which has one-tenth of the gastric cancer mortality of that in Changle.

METHODS

A total of 2424 subjects in Changle and 523 subjects in Hong Kong had endoscopic examination and venesection. Sera were tested for anti-H. pylori antibody and anti-CagA antibody and correlated with endoscopic findings.

RESULTS

In Changle, 80. 9% of the subjects were H. pylori carriers. Out of 551 carriers, 408 (74%) were positive for anti-CagA antibody. A total of 76% and 87% of the asymptomatic and gastric cancer patients were positive for anti-CagA antibody, respectively (P > 0.05). Compared to Hong Kong, there was a significantly (P < 0.0001) higher prevalence of CagA-positive strains in asymptomatic subjects in Changle (76%) than in Hong Kong (28%), but not in peptic ulcers or gastric cancers.

CONCLUSIONS

Subjects in Changle had a high prevalence of H. pylori infection and a high prevalence of the CagA-positive strains. The contrast in the prevalence of CagA-positive strains, in asymptomatic subjects in two areas with differing gastric cancer mortality, supports the pathogenic role of CagA-positive strains in gastric carcinogenesis.

Evaluation of cytokeratin 19 fragment (CYFRA 21-1) as a tumor marker in malignant pleural effusion

BACKGROUND

The aim was to investigate the diagnostic utility of CYFRA 21-1 (cytokeratin 19 fragment) as a tumor marker in pleural effusion and evaluate the value of combining CYFRA 21-1 and carcinoembryonic antigen (CEA) assays as a diagnostic aid in the malignant pleural effusion.

METHODS

One hundred and twenty-six patients (72 malignant and 54 benign pleural effusion) were included in this retrospective study. The effusion levels of CYFRA 21-1 and CEA were measured using radioimmunometric assay.

RESULTS

The median values of CYFRA 21-1 in benign and malignant pleural effusion are 15 and 70 ng/ml, respectively. Using a cut-off value of 50 ng/ml, defined at 94% specificity, the diagnostic sensitivity of CYFRA 21-1 for non-small cell lung carcinoma (n = 61), squamous cell carcinoma (n = 21), adenocarcinoma (n = 40) and small cell lung cancer (n = 11) was 64, 71, 60 and 18%, respectively. Regardless of cell types, the diagnostic sensitivity of CYFRA 21-1 and CEA in malignant pleural effusion (n = 72) was 57 and 60%, respectively (cut-off value of 10 ng/ml in CEA assay). Combining CEA with CYFRA 21-1, the diagnostic sensitivity may increase up to 72%, which was defined at 89% specificity.

CONCLUSION

CYFRA 21-1 assay may be a useful tumor marker for discriminating benign from malignant pleural effusion, especially in those of non-small cell lung cancer. The combined use of CEA and CYFRA 21-1 assay in the malignant effusion may increase the diagnostic yield compared with CEA or CYFRA 21-1 alone.

Small cell lung carcinoma associated with paraneoplastic limbic encephalitis

Limbic encephalitis is an unusual presentation of paraneoplastic syndrome. We report a case of small cell lung carcinoma associated with limbic encephalitis. A 67-year-old man presented with convulsions, memory impairment, and neuropsychiatric disturbances as initial symptoms. Subsequently, small cell lung carcinoma was diagnosed by bronchoscopic biopsy. The cerebrospinal fluid studies, electroencephalography, and magnetic resonance imaging findings had distinctive features compatible with paraneoplastic limbic encephalitis. The neuropsychiatric symptoms improved significantly after six cycles of systemic chemotherapy and adjuvant radiotherapy, resulting in partial remission of the tumor. A follow-up computed tomography scan of the head showed no evidence of intracranial metastasis 7 months after the diagnosis of cancer. Limbic encephalitis may be an initial manifestation of lung cancer. Greater awareness for diagnosis and early treatment of the primary tumor offers the best chance for improvement in patients with lung cancer presenting with limbic encephalitis.

Intrathoracic extramedullary haematopoiesis complicated by massive haemothorax in alpha-thalassaemia

Intrathoracic extramedullary haematopoiesis (EMH) is a rare entity that is usually asymptomatic. A 44 year old man with alpha-thalassaemia is described who developed dyspnoea and massive left sided haemothorax. The haemoglobin disorder was established by Hgb H staining and haemoglobin electrophoretic studies. The DNA analysis revealed it to be a case of double heterozygous terminal codon mutation with the genotype alphaalphaCS/alphaalphaT. Computed tomographic scanning and magnetic resonance imaging of the thorax showed multiple paravertebral masses which were found by thoracoscopic biopsy to be extramedullary haematopoiesis. Although no additional sclerosing pleurodesis or low dose radiation therapy was given, the lung expanded well and there has been no recurrence of haemothorax to date.

Genotype-phenotype correlations in neuronal ceroid lipofuscinosis due to palmitoyl-protein thioesterase deficiency

The infantile form of neuronal ceroid lipofuscinosis (NCL) has been well studied in Finland, where there is a high carrier frequency (1:70) for a single mutation in the causative gene, CLN1, or PPT. We have recently studied a group of 29 NCL subjects in the United States with palmitoyl-protein thioesterase (PPT) deficiency and described 19 different CLN1/PPT mutations in our population. In this report, we present a review of our previous findings, including a more detailed analysis of phenotype-genotype correlations, and present previously unpublished data concerning the clinical manifestations of the disorder in children of families with multiple affected members. Our studies indicate that about half of PPT-deficient patients in the United States are very similar to Finnish infants with INCL, but that a different mutation (R151X) accounts for 40% of U.S. alleles. The Finnish mutation (R122W) is rare in the United States. The other half of U.S. PPT-deficient patients develop symptoms after the age of 2 years, much later than Finnish patients. One common mutation (the "Scottish" allele, T75P) accounts for 13% of alleles and results in a juvenile-onset phenotype that is clinically indistinguishable from JNCL with CLN3 mutations. Other rare mutations were also associated with JNCL phenotypes, such as D79G and G250V. A preliminary expression study of two of these mutant enzymes supports the conclusion that juvenile-onset NCL (JNCL with GROD) is caused by missense mutations in the PPT gene that result in mutated enzymes with residual PPT enzyme activity.

Differential Helicobacter pylori infection rates in two contrasting gastric cancer risk regions of South China. China Gastric Cancer Study Group

BACKGROUND

Carriers of Helicobacter pylori are believed to have a three- to six-fold increased risk of developing gastric cancer. We have recently conducted a simultaneous cross-sectional population study on the prevalence of H. pylori infection in a cohort of asymptomatic adult volunteers in two contrasting gastric cancer risk regions of South China, Hong Kong and Changle of Fujian. Their mean annual gastric cancer mortality has been approximately 7.5 and 75/100 000 population, respectively, since the beginning of the last decade. The aim of this study was to evaluate if H. pylori prevalence bears any relationship to gastric cancer mortality rates in these two southern regions of China.

METHODS

Sera were obtained from 397 volunteers in Hong Kong. They were tested for anti-H.pylori immunoglobulin (Ig) G antibody by using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Volunteers of Changle (1456) had upper endoscopy examination and were also tested for anti-H. pylori IgG antibody by the same ELISA method.

RESULTS

The overall H. pylori infection prevalence was significantly higher in Changle (80.4%) than in Hong Kong (58.4%; P< 0.01). The high prevalence is associated with more atrophic gastritis. The overall risk of gastric cancer in people of Changle is approximately five-fold that of Hong Kong (adjusted odds ratio 4.9, 95% CI 2.5-9.8).

CONCLUSIONS

It is concluded that the prevalence of H. pylori infection rates bear a direct relationship to gastric cancer mortality rates in these two southern regions of China. Thus, H. pylori most likely plays a significant aetiopathogenetic role in gastric carcinogenesis in subjects living in Changle.

High frame rate imaging with a small number of array elements

Recently, a high frame rate imaging method has been developed to construct either 2-D or 3-D images (about 3750 frames or volumes/s at a depth of about 200 mm in biological soft tissues because only one transmission is needed). The signal-to-noise ratio (SNR) is high using this method because all array elements are used in transmission and the transmit beams do not diverge. In addition, imaging hardware with the new method can be greatly simplified. Theoretically, the element spacing (distance between the centers of two neighboring elements) of an array should be lambda/2, where lambda is the wavelength, to avoid grating lobes in imaging. This requires an array of a large number of elements, especially, for 3-D imaging in which a 2-D array is needed. In this paper, we study quantitatively the relationship between the quality of images constructed with the new method and the element spacing of array transducers. In the study, two linear arrays were used. One has an aperture of 18.288 mm, elevation dimension of 12.192 mm, a center frequency of 2.25 MHz, and 48 elements (element spacing is 0.381 mm or 0.591 lambda). The other has a dimension of 38.4 mmx10 mm, a center frequency of 2.5 MHz, and 64 elements (0.6 mm or 1.034 lambda element spacing). Effective larger element spacings were obtained by combining signals from adjacent elements. Experiments were performed with both the new and the conventional delay-and-sum methods. Results show that resolution of constructed images is not affected by the reduction of a number of elements, but the contrast of images is decreased dramatically when the element spacing is larger than about 2.365 lambda for objects that are not too close to the transducers. This suggests that an array of about 2.365 lambda spacing can be used with the new method. This may reduce the total number of elements of a fully sampled 128x128 array (0.5 lambda spacing) from 16384 to about 732 considering that the two perpendicular directions of a 2-D array are independent (ignoring the larger element spacing in diagonal directions of 2-D arrays).

Effect of the compression ratio on properties of lung surfactant (bovine lipid extract surfactant) films

Using axisymmetric drop shape analysis (ADSA) and a captive bubble technique, the properties of lung surfactant (BLES) films under different compression ratios (i.e. the ratio of maximum to minimum surface area of the bubble) were investigated. In particular, the effect of the compression ratio of the films on the shape of the volume area surface tension-time (VAST) graphs and on the shape of the surface tension relative area (gamma-A ) graphs was examined at the air-liquid interface. Under relatively low compression ratios of the films, the VAST and gamma-A graphs indicate that the cycling is reversible (i.e. the gamma-A graphs are identical for expansion and compression). When the compression ratio of the films increases, failure tends to occur when the surface film can not support the increasing surface pressure, causing a hysteresis loop in the gamma-A graph. It was also found that low surface tension (i.e. below 5 mJ/m2) at the interface could be attained with a 30% compression ratio and collapse of the films always occurs near or below 1 mJ/m2.

Effect of culture media on antheridial configuration in Phytophthora boehmeriae

The position of the antheridium on the oogonium of Phytophthora boehmeriae was greatly affected by culture media. Agar medium containing lecithin and basal salts and corn grain agar favored the production of paragynous antheridia, while corn meal agar, lima bean agar, vegetable juice agar, and tomato agar were conducive to formation of amphigynous antheridia. The effect of culture media on antheridial configuration was found to be due to nutrient concentration. A high concentration of nutrients in the media was favored the formation of amphigynous antheridia, and a low concentration of nutrients favored paragynous antheridia.Key words: antheridial configuration, oogonium, nutrients, Phytophthora boehmeriae.

Molecular genetics of palmitoyl-protein thioesterase deficiency in the U.S

Mutations in a newly described lysosomal enzyme, palmitoyl-protein thioesterase (PPT), were recently shown to be responsible for an autosomal recessive neurological disorder prevalent in Finland, infantile neuronal ceroid lipofuscinosis. The disease results in blindness, motor and cognitive deterioration, and seizures. Characteristic inclusion bodies (granular osmiophilic deposits [GROD]) are found in the brain and other tissues. The vast majority of Finnish cases are homozygous for a missense mutation (R122W) that severely affects PPT enzyme activity, and the clinical course in Finnish children is uniformly rapidly progressive and fatal. To define the clinical, biochemical, and molecular genetic characteristics of subjects with PPT deficiency in a broader population, we collected blood samples from U.S. and Canadian subjects representing 32 unrelated families with neuronal ceroid lipofuscinosis who had GROD documented morphologically. We measured PPT activity and screened the coding region of the PPT gene for mutations. In 29 of the families, PPT deficiency was found to be responsible for the neurodegenerative disorder, and mutations were identified in 57 out of 58 PPT alleles. One nonsense mutation (R151X) accounted for 40% of the alleles and was associated with severe disease in the homozygous state. A second mutation (T75P) accounted for 13% of the alleles and was associated with a late onset and protracted clinical course. A total of 19 different mutations were found, resulting in a broader spectrum of clinical presentations than previously seen in the Finnish population. Symptoms first appeared at ages ranging from 3 mo to 9 yr, and about half of the subjects have survived into the second or even third decades of life.

Spindle cell carcinoma of the lung: a clinicopathologic presentation of three cases

Three patients with spindle cell carcinoma located in the lower respiratory tract are presented, including cases of two monophasic and one biphasic tumor. On light microscopic examination, the spindle cell components of the tumors were histologically characterized by sheets of fusiform spindle cells that closely resembled a sarcoma. Keratin expression in the spindle cell components of these tumors, as shown by anti-cytokeratin antibody staining, demonstrated their epithelial nature. It is supposed that the spindle cell component displays a spectrum of phenotypes originating from epithelial cells with varying degrees of mesenchymal transformation. It is difficult to establish a diagnosis of this rare primary pulmonary malignancy prior to surgical intervention. A review of the literature allowed for a summary of the clinicopathologic characteristics of this tumor.

Experimental study of high frame rate imaging with limited diffraction beams

Limited diffraction beams have a large depth of field and have many potential applications. Recently, a new method (Fourier method) was developed with limited diffraction beams for image construction. With the method and a single plane wave transmission, both 2D (two-dimensional) and 3D (three-dimensional) images of a very high frame rate (up to 3750 frames/s for a depth of 200 mm in biological soft tissues) and a high signal-to-noise ratio (SNR) can be constructed with relatively simple and inexpensive hardware. If limited diffraction beams of different parameters are used in both transmission and reception and transducer aperture is shaded with a cosine function, high-resolution and low-sidelobe images can be constructed with the new method without montage of multiple frames of images [the image quality is comparable to that obtained with a transmit-receive (two-way) dynamically focused imaging system]. In this paper, the Fourier method was studied with both experiment and computer simulation for 2D B-mode imaging. In the experiment, two commercial broadband 1D array transducers (48 and 64 elements) of different aperture sizes (18.288 and 38.4 mm) and center frequencies (2.25 and 2.5 MHz) were used to construct images of different viewing sizes. An ATS539 tissue-equivalent phantom of an average frequency-dependent attenuation of 0.5 dB/MHz/cm was used as a test object. To obtain high frame rate images, a single plane wave pulse (broadband) was transmitted with the arrays. Echoes received with the arrays were processed with both the Fourier and conventional dynamic focusing (delay-and-sum) methods to construct 2D B-mode images. Results show that the quality (resolution and contrast) of constructed images is virtually identical for both methods, except that the Fourier method is simpler to implement. Both methods have also a similar sensitivity to phase aberration distortions. Excellent agreement among theory, simulation, and experiment was obtained.

The acting site of bronchodilator, methacholine and upper respiratory tract infection on airways

BACKGROUND

The bronchodilator agent is an important drug for patients with chronic obstructive pulmonary disease. Methacholine is a popular bronchial provocative agent. Although the major acting site of bronchodilator, methacholine and upper respiratory tract infection (URI) has been evaluated in some studies, the sites are still in debate. This study investigated the exact major acting sites.

METHODS

Thirty subjects participated in this study. Episodes of URI were identified by a questionnaire. Spirometry, bronchial provocative test with methacholine, and five minutes' inhalation of a mixture of helium and oxygen (HeO2) were done on day one. Spirometry, bronchodilator test, with five minutes' inhalation of HeO2 and expiratory flow-volume (F-V) curve were performed on another day. The change of pre- and post-HeO2 VEMax50 was calculated as delta VEMax50. The pre- and post-bronchodilator VEMax50 and delta VEMax50 differences were counted to decide the acting site of bronchodilator. After bronchial provocative test with methacholine, the volume of isoflow (VisoV) was estimated from pre- and post-HeO2 F-V curve to establish the acting site of methacholine.

RESULTS

This study indicated that small airways are the major acting sites of bronchodilators, large airways are the major acting sites of methacholine and URI affects mainly large airways. Although airway hyperresponsiveness is more severe in subjects with positive methacholine response, the recovery of spirometry values is not significantly different between the methacholine-positive and -negative groups.

CONCLUSIONS

The major acting sites of the bronchodilator, methacholine, and URI are the small, large and large airways, respectively. Bronchial hyperresponsiveness is not a cause of quick restoration of spirometry values in subjects with positive methacholine response.

Palmitoyl-protein thioesterase and the molecular pathogenesis of infantile neuronal ceroid lipofuscinosis

Palmitoyl-protein thioesterase (PPT) has recently been shown to be the defective enzyme underlying the infantile form of neuronal ceroid lipofuscinosis (INCL). In this paper, we review the enzymology of PPT, evidence for its localization in lysosomes, and recent advances in understanding the metabolic defect caused by PPT deficiency. Absence of PPT activity in lysosomes isolated from INCL lymphoblasts is demonstrated. A model for the formation of the storage bodies in INCL involving defective autophagocytic proteolysis is proposed.

Designing limited diffraction beams

Theoretically, limited diffraction beams can only be produced with an infinite aperture. In practice, they can be closely approximated with a finite aperture over a large depth of field. Because of this property, these beams could have applications in medical imaging, tissue characterization, Doppler velocity estimation, and nondestructive evaluation (NDE) of materials, as well as other physics-related areas such as electromagnetics and optics. In this paper, a new method is developed to design limited diffraction beams of desired beam shapes within a finite aperture of interest. It uses previously discovered limited diffraction beams such as Bessel beams and X waves as basis functions, and constructs new beams with linear superpositions of the bases. To construct a new beam of a desired shape, coefficients of the basis functions in the linear superposition are chosen so that the difference between the new beam and a desired beam is minimized under the criterion of least-squares error within the aperture. This procedure is implemented by digitizing both the basis beams and desired beams in the aperture and solving a system of linear equations from its normal equation. The method is applied to several desired beams that are limited diffraction beams known previously. Results show that the designed beams and the desired beams are virtually identical. If the desired beams are not solutions to the wave equation, the designed beams are new limited diffraction beams that are similar in shapes to the desired beams. This suggests that the method may be a powerful and practical tool for developing new limited diffraction beams of desired properties.

Lipid thioesters derived from acylated proteins accumulate in infantile neuronal ceroid lipofuscinosis: correction of the defect in lymphoblasts by recombinant palmitoyl-protein thioesterase

Palmitoyl-protein thioesterase is a lysosomal long-chain fatty acyl hydrolase that removes fatty acyl groups from modified cysteine residues in proteins. Mutations in palmitoyl-protein thioesterase were recently found to cause the neurodegenerative disorder infantile neuronal ceroid lipofuscinosis, a disease characterized by accumulation of amorphous granular deposits in cortical neurons, leading to blindness, seizures, and brain death by the age of three. In the current study, we demonstrate that [35S]cysteine-labeled lipid thioesters accumulate in immortalized lymphoblasts of patients with infantile neuronal ceroid lipofuscinosis. The accumulation in cultured cells is reversed by the addition of recombinant palmitoyl-protein thioesterase that is competent for lysosomal uptake through the mannose-6-phosphate receptor. The [35S]cysteine-labeled lipids are substrates for palmitoyl-protein thioesterase in vitro, and their formation requires prior protein synthesis. These data support a role for palmitoyl-protein thioesterase in the lysosomal degradation of S-acylated proteins and define a major new pathway for the catabolism of acylated proteins in the lysosome.

Outbreak of bronchiolitis obliterans associated with consumption of Sauropus androgynus in Taiwan

BACKGROUND

In August, 1995, there was an outbreak in Taiwan of rapidly progressive respiratory distress associated with consumption of uncooked Sauropus androgynus, a vegetable with a claimed yet unconfirmed effect on weight control. We report on 23 patients with strikingly similar clinical presentations.

METHODS

A structured questionnaire for clinical manifestations was completed. Radiographic findings, pulmonary physiological changes, immunological and microbiological studies, and pathological examination were evaluated.

FINDINGS

All patients were young and middle-aged women (mean age 39 years [range 21-52]). They took uncooked S androgynus juice, generally mixed with guava or pineapple juice, for a mean duration of 10 weeks. Progressive dyspnoea and persistent cough were the main symptoms on presentation. Pulmonary function testing uniformly revealed moderate to severe airflow obstruction with mean forced expiratory volume in 1 s (FEV1) of 0.66 L (26% of predicted). No bronchodilator response was observed. Room-air arterial blood gas analysis showed hypoxaemia (mean PaO2 9.6 [SD 1.6] kPa). Chest radiographs were essentially normal. High-resolution computed tomography showed bilateral bronchiectasis and patchy low attenuation of lung parenchyma with mosaic perfusion. Ventilation-perfusion scintigraphic findings were compatible with obstructive lung disease. Histopathology of open lung biopsy specimens in four patients confirmed the presence of bronchiolitis obliterans. Immunohistochemical stains of the open lung biopsy specimens showed predominance of T cells over B cells. Immunofluorescent stains for IgG, IgM, IgA, C1q, C3, and C4 were negative. Serum concentrations of tumour necrosis factor alpha were higher than those of normal controls. Clinical response to prednisolone was limited.

INTERPRETATION

We describe an unusual association between bronchiolitis obliterans and ingestion of the vegetable S androgynus. T-cell mediated immunity may be involved in the pathogenesis.

Ultrastructure and human papillomavirus DNA in papillomatosis of external auditory canal

BACKGROUND

A viral etiology has been suspected in papillomatosis of the external auditory canal (PEAC), but virus particles have not been detected so far, although they are easily demonstrable in skin warts. The purpose of the study was to solve this discrepancy by the use of polymerase chain reaction (PCR).

MATERIALS AND METHODS

Specimens from the external auditory canal of 14 patients with PEAC, but no human papilloma virus infection of the genital areas, were examined histologically by light and electron microscopy, as well as by PCR to detect viral DNA.

RESULTS

Histologically, papillomatosis was present in all specimens. Vacuolated cells were found in the upper part of the stratum malpighii in five cases. On electron microscopy, the numbers of perichromatin and interchromatin granules were increased, but no viral granules were observed. In all specimens, DNA of HPV 6 was detected using PCR, but there was no evidence of DNA of other HPV.

CONCLUSIONS

Papilloma of the external auditory canal is produced by infection with HPV 6.

Digital ischemia associated with lung cancer: a case report

Digital ischemia or necrosis has unusually been associated with neoplasm. The occurrence of cryoglobulinemia and lung cancer with digital ischemia has been extremely rare in the past. This report concerns a case with adenocarcinoma of the lung associated with cryoglobulinemia, with rapidly developing digital ischemia of the tips of fingers and toes. Following concurrent chemoradiotherapy, there was improvement in digital ischemia and disappearance of serum cryoglobulin. The mechanisms of neoplasm-associated digital ischemia are complex; however, the cryoglobulinemia and probable arteritis may have played important roles in producing the ischemic symptoms in this case.