Low-dissolved-oxygen nitrification in tropical sewage: an investigation on potential, performance and functional microbial community.

Intensive aeration for nitrification is a major energy consumer in sewage treatment plants (STPs). Low-dissolved-oxygen (low-DO) nitrification has the potential to lower the aeration demand. However, the applicability of low-DO nitrification in the tropical climate is not well-understood. In this study, the potential of low-DO nitrification in tropical setting was first examined using batch kinetic experiments. Subsequently, the performance of low-DO nitrification was investigated in a laboratory-scale sequential batch reactor (SBR) for 42 days using real tropical sewage. The batch kinetic experiments showed that the seed sludge has a relatively high oxygen affinity. Thus, the rate of nitrification was not significantly reduced at low DO concentrations (0.5 mg/L). During the operation of the low-DO nitrification SBR, 90% of NH4-N was removed. The active low-DO nitrification was mainly attributed to the limited biodegradable organics in the sewage. Fluorescence in-situ hybridisation and 16S rRNA amplicon sequencing revealed the nitrifiers were related to Nitrospira genus and Nitrosomonadaceae family. Phylogenetic analysis suggests 47% of the operational taxonomic units in Nitrospira genus are closely related to a comammox bacteria. This study has demonstrated active low-DO nitrification in tropical setting, which is a more sustainable process that could significantly reduce the energy footprint of STPs.

A critical review on the current state of antimicrobial glove technologies: advances, challenges and future prospects.

Following recent viral outbreaks, there has been a significant increase in global demand for gloves. Biomedical research focuses increasingly on antimicrobial gloves to combat microbial transmission and hospital-acquired infections. Most antimicrobial gloves are manufactured using antimicrobial chemicals such as disinfectants, biocides and sanitizers. The design of antimicrobial gloves incorporates advanced technologies, including colloidal particles and nanomaterials, to enhance antimicrobial effectiveness. A category of antimicrobial gloves also explores and integrates natural antimicrobial benefits from animals, plants and micro-organisms. Many types of antimicrobial agents are available; however, it is crucial that the selected agent exhibits a broad spectrum of activity and is not susceptible to promoting resistance. Additionally, future research should focus on the potential effect of antimicrobial gloves on the skin microbiota and irritation during extended wear. Careful integration of the antimicrobial agent is essential to ensure optimal effectiveness without compromising the mechanical properties of the gloves.

Epstein-Barr virus-associated intravascular lymphomatosis within Kaposi's sarcoma in an AIDS patient.

Intravascular lymphomatosis (IL) is an unusual neoplasm characterized by multifocal proliferation of lymphoma cells exclusively within the blood vessels. We report here a patient with acquired immunodeficiency syndrome (AIDS) and disseminated Kaposi's sarcoma. A 233-bp amplification product of HHV-8 was detected in the DNA extracted from specimens of Kaposi's sarcoma at different sites by polymerase chain reaction (PCR). At autopsy, the vessels within the Kaposi's sarcoma were dilated and filled with atypical large mononuclear cells. No such feature was seen in the vessels of non-Kaposi's sarcomatous regions. Immunohistochemically, the spindle cells of Kaposi's sarcoma were positive for CD31 (endothelial cell marker). The intravascular tumor cells were positive for CD45 (leukocyte common antigen) but negative for others, including chloroacetate esterase, CD45-RO (UCHL-1, Pan-T), CD3, CD43, CD20 (L26, Pan-B), CD30 (Ki-1), immunoglobulin heavy chains and light chains, CD56 (natural killer cell antigen), and CD31. Monoclonal rearrangement of immunoglobulin heavy chain gene was detected in the DNA extracts from fresh tissue of Kaposi's sarcoma by PCR, which indicated that the lymphoma cells within the Kaposi's sarcoma were of monoclonal B cell origin. In situ hybridization revealed that EBER-1 transcripts were present in the lymphoma cells of IL but not in the spindle cells of Kaposi's sarcoma. To the authors' best knowledge, this is the first instance of IL in an AIDS patient with direct evidence of EBV association.

Localization of HPV-16 DNA sequence in CaSki cells by electron microscopic hybridocytochemistry.

We investigated the HPV-16 DNA sequence in the CaSki cervical carcinoma cell line by electron microscopic hybridocytochemistry using biotinylated HPV-16/18 probes. At the light microscopic level, reaction product of hybridized HPV-16 DNA sequence was not seen in the cytoplasm but appeared as spots or rods randomly distributed in the nuclei. By electron microscopy, reaction product was seen aggregated in several regions in the nuclei. Most of the stained areas did not reveal particular architecture but showed part of the chromatin structure. In other nuclei, reaction product was observed to be associated with strings of loop-like structure, and some stained loops were seen to be connected directly to the nuclear filamentous chromatin structure. The skeletonized images of hybridized HPV-16 DNA in the nuclei were illustrated by computerized image analysis. In conclusion, we have demonstrated the HPV-16 DNA sequence in the nuclei of CaSki cells by electron microscopy. The identification of stained areas localized only in the chromatin suggests an integrated form of HPV-16 DNA sequence in the cells. This method could be used to identify an integrated or episomal form of viral DNA in the virus-containing cells.

Diagnostic accuracy of transesophageal echocardiography for detecting left atrial thrombi in patients with rheumatic heart disease having undergone mitral valve operations.

Transesophageal echocardiography (TEE) has emerged as an efficient method for detecting left atrial (LA) thrombi in recent years, but its accuracy has not been fully evaluated. A prospective clinicopathologic study in 213 consecutive patients with chronic rheumatic mitral valve disease over a period of 39 months was undertaken. All patients underwent open heart surgery within 3 days after the TEE study. The presence or absence of LA thrombi was confirmed at surgery by direct inspection of the left atrium and proven by histopathologic examination. Of the 213 patients, 147 had predominant mitral stenosis, and the remaining 66 patients had significant mitral regurgitation. Twenty-eight patients had LA thrombi by TEE criteria. These findings were all confirmed at surgicopathologic studies (specificity 100%). However, in 2 patients, LA thrombi were present but could not be detected by TEE (sensitivity 93.3%). Therefore, the positive predictive value was 100%, the negative predictive value was 98.9% and the diagnostic accuracy was 99.1%. No thrombi were found in patients with significant mitral regurgitation. The frequency of LA thrombi in patients with predominant mitral stenosis was 20% (30 of 147), and most of these patients had chronic atrial fibrillation (28 of 30, 93%). Only 16 patients (16 of 30, 53%) were found to have LA thrombi by transthoracic echocardiography. Furthermore, our data showed poor correlation between the echogenicity of LA thrombi and the degree of thrombus organization. Thus, TEE is excellent for detecting LA thrombi in patients with rheumatic heart disease severe enough to warrant mitral valve operations.

Atypical myxoma.

We report the case of a 38-year-old woman with a large thin-walled cystic mass (6 x 5 x 4.5 cm) filled with arterial blood in the right atrium. The cystic mass with blood content was clearly delineated by transesophageal cross-sectional echocardiography and magnetic resonance imaging of the heart. At operation, a silver-whitish, smooth surfaced cystic mass was found attached to the free wall of the right atrium between the superior vena cava and the right atrial appendage with a broad base. Microscopically, the wall of the cyst was composed of stellate mesenchymal cells embedded within a myxoid matrix which was proved by alcian blue stain. To our knowledge, this type of cardiac myxoma has not been previously reported.

Growth of the aortic anastomosis in pigs. Comparison of continuous absorbable suture with nonabsorbable suture.

Growth at the anastomotic site after continuous vascular anastomosis in the pediatric patient remains a problem. Primary end-to-end anastomosis of the infrarenal aorta was performed with absorbable Maxon suture or nonabsorbable Prolene suture in 20 piglets. Ten of the Maxon suture group and nine of the Prolene suture group survived; one pig died of infection. The animals were put to death 6 months after the operation. Each abdominal aorta was removed and a roentgenogram was obtained. The aorta was then burst-tested to 300 mm Hg, measured, and examined both grossly and histologically. All anastomoses were patent and no burst failures were observed in either group. However, Prolene sutures protruded into lumen and were partially embedded in the aortic wall in all animals in the Prolene suture group. Thrombus adhered to the intraluminal Prolene suture in six of nine animals. The growth of the anastomotic area was wider in the Maxon suture group (446.4% +/- 131.8% versus 317.6% +/- 121.5%, p less than 0.05). Stenosis was more common in the Prolene suture group (7/9) than in the Maxon suture group (1/10) (p less than 0.01), but the distal segment was widely patent in both groups. Dilatation at the anastomotic site was present in eight of 10 pigs in the Maxon suture group and in two of nine in the Prolene suture group. Histologic study showed that the area of tissue reaction was more prominent in the Prolene suture group. No sutures were observed in the Maxon suture group. We therefore recommend the use of absorbable Maxon sutures for anastomoses in which the suture line must be able to grow.

Cardiac metastasis of hepatocellular carcinoma mimicking pericardial effusion on radionuclide angiocardiography.

A 51-year-old man presented with exertional dyspnea for two months. He had a history of hepatocellular carcinoma that was totally resected three years earlier. Radionuclide angiocardiography disclosed a large photopenic area separating the heart from the liver, and lung blood pools mimicking a large pericardial effusion. Echocardiography and magnetic resonance imaging of the heart, however, showed extensive tumor infiltration of the myocardium of both ventricles. Endomyocardial biopsy confirmed the diagnosis of metastatic hepatocellular carcinoma. There was no evidence of recurrent hepatoma in the liver.

Anomalous pulmonary venous pathway traversing pulmonary parenchyma. Diagnosis and implication.

STUDY OBJECTIVES: To describe four patients having total anomalous pulmonary venous connection with an intrapulmonary vertical vein, rendering difficulty in diagnosis and surgery. SETTING: a tertiary referral center. PATIENTS AND METHODS: By reviewing medical records, 4 of 25 patients with right atrial isomerism and total anomalous pulmonary venous connection were identified to have an intrapulmonary vertical vein. All four patients underwent echocardiography, catheterization, and angiography. One underwent MRI. Two underwent open-heart surgery and one received a modified Blalock-Taussig shunt. RESULTS: Right atrial isomerism was present in all four patients. On chest x-ray films, an abnormal shadow resembling scimitar syndrome was seen in two patients. Imaging the vertical vein was unsuccessful with an echocardiogram in all four patients. The intrapulmonary course of the vertical vein was depicted with a pulmonary venogram in two patients and with magnetic resonance in one patient. The intrapulmonary segment remained undetected until autopsy in one patient. All four patients died. At autopsy, the pulmonary venous confluence was hypoplastic in all four hearts. The vertical vein was buried in pulmonary parenchyma and drained to superior vena cava with significant obstruction. CONCLUSION: In the presence of right atrial isomerism and total anomalous pulmonary venous connection, there may be an intrapulmonary pulmonary venous connection that may be obstructed. Anastomosing the pulmonary venous confluence to the atrium may be difficult because of hypoplasia of the pulmonary venous confluence.

Pancreatic carcinoma associated with chronic calcifying pancreatitis in Taiwan: a case report and review of the literature.

A 62-year-old Chinese woman suffering from pancreatic carcinoma coexisting with chronic calcifying pancreatitis is reported. Ultrasonography and computed tomography disclosed multiple intraductal calcifications in the pancreatic head and body and a tumor at the tail. Laparotomy revealed cancerous peritonitis in addition to verifying the presence of calcifications at the head and body and a cancer at the tail. Histology confirmed adenocarcinoma. The incidence of pancreatic carcinoma in chronic calcifying pancreatitis varied from 0.8 to 25% in a thorough review of the literature. It is emphasized that patients with chronic calcifying pancreatitis should be closely followed for detection of possible coexisting pancreatic malignancies.

Is the sinus node visible grossly? A histological study of normal hearts.

The sinus node is said to be occasionally visible in the human heart, while some have denied this visibility. This histological study of the normal sinus node was made on 11 adults and 10 infants. The node was always located subepicardially along the terminal groove at the junction of the superior caval vein and the right atrium. When no fatty infiltration (all infants and 2 adults) or minimal fatty tissue (2 adults) was found over the epicardial side of the node, it was not visible grossly. When fatty infiltration was obvious, then the node could be identified grossly as a yellowish spindle-shaped structure along the terminal groove. This arrangement was observed in 7 adults. The majority of nodes were in lateral position, but the so-called horseshoe arrangement was seen in 2 infants and 2 adults. The artery to the sinus artery was located centrally or eccentrically in the majority of cases, but the artery ramified through the nodal substance in 1 infant and 4 adults. We conclude that the node is not visible grossly in either the infant hearts or in those adult hearts without fatty infiltration. The whole cephalic part of the terminal groove should be carefully avoided to be sure of preventing the injury to the node during cardiac surgery.

Familial medulloblastoma in siblings: report in one family and review of the literature.

Two siblings in a family--a 5-year-old boy and an 8-year-old girl--suffered from progressive headache and gait disturbance in an interval of 1 year, consecutively. Neurologic manifestations were papilledema and truncal ataxia. Both of their computed tomography scans showed a large, well-enhanced tumor located in the cerebellar vermis with secondary hydrocephalus. Both had surgical resection followed by craniospinal irradiation and then chemotherapy. The pathologic findings confirmed the diagnosis of medulloblastomas. The family pedigree disclosed some other cancer in close relatives. These findings suggested a possible role of heredity in the oncogenesis of this tumor. To our knowledge, our cases are the seventh report of familial medulloblastoma occurring in nontwin siblings in the world.

Extrarenal Wilms' tumor--a case report.

Extrarenal Wilms' tumor is extremely rare. To our knowledge, only 22 cases had been reported up to 1984. We treated a 5-year-old girl with an extrarenal Wilms' tumor arising in the right inguinal region. Total excision was performed. Abdominal sonogram, computed tomography (CT) scan, and intravenous pyelogram (IVP) showed normal kidneys, no other mass, and no evidence of metastasis. Postoperative chemotherapy was administered. The patient has been disease-free since first diagnosis 19 months ago.

Simple bone cyst in cervical vertebral spinous process and laminae: report of a case.

Simple (unicameral or solitary) bone cysts are the only true cysts of primary intraosseous origin. These cysts involve the metaphysis of long tubular bones such as the proximal humerus and proximal femur and, occasionally, the proximal tibia, distal femur, patella, ilium, rib, and calcaneus. They are very rarely found in vertebrae, especially in the cervical vertebral spinous process and laminae. We report a 14-year-old boy with an expansile, bubbly cystic lesion in the spinous process and laminae of the seventh cervical vertebra. Histopathologic examination showed a cyst surrounded by thin fibrous or fibro-osseous wall without any lining epithelial cells, compatible with a simple bone cyst. As far as we know, this is the first case of simple bone cyst involving the spinous process and laminae of a cervical vertebra reported in Taiwan.

[Experimental hip dysplasia in the rabbit].

Neglected cases of congenital dislocation of the hip (CDH) always present with profoundly interesting X rays and pathoanatomical changes. Because of progressive dysplastic change, it is difficult to determine clinically at what stage a patient can not have reconstructive surgery. We used an animal model to induce hip dysplasia in order to understand the mechanism of dislocation and to demonstrate the dysplastic changes at various ages of dislocation. We used a plastic tube to immobilize the left knee of one week old New Zealand white rabbits in the extension position. Fifty-five rabbits in a natural history group were examined physically, radiographically and pathologically every month, until five months old. Ten rabbits were also studied by computed tomography before sacrifice. Forty-two rabbits which had been immobilized for more than 2 months were selected to determine the changes in their left hips. Tenotomy of the hamstrings of the left knee was performed in another 20 rabbits, which were then immobilized in the same way until 2 months old. The changes in their left hips were also determined and compared with the changes of former group. In our study, immobilization of the left knee of rabbits can induce dislocation, subluxation or no change. Tenotomy of the hamstrings can decrease the incidence of dislocation and subluxation, but cannot avoid their occurrence. In long-term observation of rabbits with dislocation and subluxation, we found that there are more dysplastic and degenerative changes in older rabbits. Computed tomography proved to be an effective evaluation tool of the size of dysplastic acetabulum and femoral head.

Bizarre parosteal osteochondromatous proliferation of the phalanx: report of a case.

The bizarre parosteal osteochondromatous proliferation of the hand and foot is a benign lesion which occasionally may mimic osteochondromas, chondrosarcomas or osteosarcomas clinically, radiologically and histopathologically. This rare benign entity should be recognized in order to avoid unwarranted destructive therapy. The authors report a case of this disease and discuss the differential diagnosis and the relevant features of this disease entity. A 27-year-old female patient suffered from a painful swelling at the proximal middle phalanx of the right middle finger for five months. The lesion was excised but the residual lesion developed a distinct parosteal growth by radiologic studies one-and-a-half years later. The patient underwent reexcision of the lesion twice. No recurrence was noted 11 months following the last excision. Histopathologically, the first specimen contained bizarre chondrocytes. The recurrent nodular tumors, submitted in the second and third operations, were composed of cancellous bone with fatty marrow and a few marrow elements, and focally capped by cartilage. The adjacent soft tissue contained proliferating fibrous tissue. The osteochondral junctions in the latter two specimens were irregular. We believe that the documentation of this tumor at different stages of development has helped in the further understanding of this rare entity.

Primary malignant tumor of the small intestine.

The records of 101 patients with primary small intestinal malignant tumor at NTUH, collected from 1960 to 1989, were reviewed. These patients represented 1.2% of the patients with gastrointestinal cancer at NTUH over the same period. Fourty-two (41.6%) of the cancer patients had lymphomas, 30(29.7%) had adenocarcinomas, 26 (25.7%) had leiomyosarcomas, and 3(3.0%) had carcinoid tumors. The average age at cancer presentation was 47.5 years (range from 3 to 96). The lymphoma patients had an average age of 35.1 years, while adenocarcinoma patients averaged 60.4 years of age. Leiomyosarcoma and carcinoid tumors averaged 51.2 years and 59 years, respectively. There were 65 male patients and 36 female patients, and there was a male predominance in all groups except for the leiomyosarcoma group which had an equal sex ratio. Generally speaking, the incidence rate for the areas involved were similar in the duodenum, jejunum and ileum. However, adenocarcinomas were more common in the duodenum (53%) and 45% of lymphomas were found in the ileum, as were the carcinoid tumors (66%). The most common presenting symptom was abdominal pain (62%), with bleeding second (32%). Obstruction and palpable mass together were present in 29% of the cases. Body weight loss was found in 25% of patients, and 14% of the patients presented with acute abdomen due to intestinal perforation. Laparotomy was the most common diagnostic procedure (60%). Preoperative diagnoses were possible in cases of duodenal and upper intestinal malignancies, but were rarely possible in patients with lower intestinal malignancies. Sixty-eight patients (68%) underwent tumor resection for palliation or cure. The operation mortality was 4%.(ABSTRACT TRUNCATED AT 250 WORDS)

The atrioventricular conduction axis of hearts with isolated ventricular septal defects.

We studied the surgical anatomy of 14 hearts with isolated ventricular septal defects and the precise relationship of the atrioventricular conduction axis to their rims. Ten of these hearts were investigated by serial sectioning of their atrioventricular conduction systems. All defects were divided into perimembranous or muscular types as previously suggested by Soto et al. The distinguishing feature of the perimembranous defect was that the central fibrous body formed part of its rim, this fact indicated that the conduction tissue was always to the right of the surgeon's hand when the defect was approached through the right atrium. The precise relationship of the ventricular conduction tissues varied depending upon whether the perimembranous defect extended into the inlet, trabecular or outlet components of the muscular septum. The nonbranching bundle was closest to the septal rim in the inlet and trabecular defects, frequently being buried in a remnant of the interventricular membranous septum. However, in these defects the nonbranching and branching bundles were also found in other specimens remote from the septal crest, yet were carried on the left ventricular aspect of the septum. In perimembranous inlet defects, the penetrating bundle detoured deep into the central fibrous body. In perimembranous outlet defects, the conduction tissues were remote from the septal crest. In contrast to these findings, the conduction tissues were away from the edges of the defects in trabecular and outlet muscular defects. In conclusion, in the perimembranous inlet defect, the placement of the sutures on the annulus of tricuspid valve should be avoided in view of its abnormal long penetrating bundle.

Cardiac amyloidosis presenting as sick sinus syndrome and intractable heart failure: report of a case.

Cardiac amyloidosis, an uncommon disease, has been reported to manifest as congestive heart failure (CHF) and/or various arrhythmias. Herein, we report a case of CHF and sick sinus syndrome. The patient, a 66-year-old man, was admitted to the National Taiwan University Hospital because of dizzy spells and recurrent syncope. Electrocardiogram showed a sinoatrial block, first degree atrioventricular block, right bundle branch block and low-voltage Q wave, R wave and S wave (QRS) complex. Prolonged corrected sinus node recovery time was documented by an atrial pacing study. A permanent pacemaker was implanted for the patient's bradyarrhythmia, but he developed progressive heart failure. Echocardiography revealed a normal-sized ventricular chamber, concentric left ventricular hypertrophy with a "granular sparkling" appearance of the myocardium, and impaired diastolic and systolic function of the left ventricle. Despite aggressive treatment, the patient expired due to intractable heart failure. Postmortem needle aspiration revealed amyloidosis involving the heart, lung and skin. We conclude that cardiac amyloidosis should be considered in elderly patients with conduction disturbance and unexplained congestive heart failure.

Investigation into allergic response in patients with chronic sinusitis.

We attempted to investigate the role of nasal allergy in sinusitis to elucidate whether it results from an immediate-type allergic reaction of the sinus mucosa or from allergic edema-induced sinus ostial obstruction. Forty-two patients with chronic sinusitis were selected for allergen skin tests, measurements of serum total and specific IgE, and sinus tissue-specific IgE. The data were then correlated to examinations of nasal mucosal scrapings and histopathology of the sinus mucosa. We found that serum levels of total IgE and house dust mite-specific IgE antibodies were significantly higher in patients (n = 12) allergic to house dust than in the nonatopics (n = 30; p less than 0.0001). There was no difference in the sinus tissue-specific IgE antibody. Eosinophils and basophilic cells in epithelial scrapings from the inferior turbinates, assessed by Hansel staining, were high in 66.7% and 50% of the atopic patients, respectively, and 36.7% and 26.7% of the nonatopics, respectively. The rates were influenced by the existence of infection and nasal polyps. The increase in eosinophils, mast cells and plasma cells, assessed by histopathologic examination, were not prevalent in the sinus mucosa of atopic patients. It is concluded that nasal allergy may be a predisposing factor to sinusitis and that the pathologic change of the sinus mucosa is mainly secondary, due to sinus ostial obstruction.