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Biomedical subjects

F K Chong

Publications and source records attributed to F K Chong.

15 recordsLinked to original sources
PubMed1997

Vector potential of houseflies (Musca domestica) for Helicobacter pylori.

The mode of transmission of Helicobacter pylori is unknown. Since viable bacteria have been shown to be excreted in feces from infected individuals and houseflies habitually develop and feed on excrement, we hypothesized that flies ingest and harbor H. pylori and, in turn, contaminate the human environment. This study examined the possible vector potential of houseflies (Musca domestica) for H. pylori. Caged houseflies were exposed to freshly grown H. pylori on agar plates. After a 6-h feeding period, the plates were removed and were replaced with sterile petri dishes containing a droplet of sterile brucella broth. At regular intervals, small numbers of houseflies were removed for microbiological and histological analysis, and the petri dishes were replaced with fresh sterile plates with fresh drops of brucella broth. The flies' bodies, the flies' dissected alimentary tracts, and excreta on the petri dishes were cultured for H. pylori, whose identity was confirmed by the urease, catalase, and oxidase reactions and Gram staining. In contrast to control flies, viable H. pylori could be isolated from external surfaces for up to 12 h and from gut and excreta for as long as 30 h after the initial feeding period. After 30 h other gram-negative bacteria overgrew the cultures of samples from all locations tested, rendering the selective culture of H. pylori colonies impossible. Histological analysis revealed Helicobacter-like organisms in the gut lumen and attached to intestinal epithelial cells. We conclude that houseflies can harbor viable H. pylori on their bodies and in their intestinal tracts. They are also able to disseminate viable H. pylori in excreta, and they may therefore present a significant reservoir and be a vector in the transmission of H. pylori.

Animals↗
PubMed1992

Hidden colonic adenomas in a patient with a family history of polyposis.

We describe an asymptomatic patient with a strong family history of polyposis who was found to have flat and depressed adenomas that were not visible on colonoscopy. The diagnosis required assessment of multiple, randomly obtained biopsy specimens. Partial deflation of the colon during colonoscopy may allow hidden lesions to be seen. Biopsies should be performed in all patients with a family history of polyposis who are examined colonoscopically, even if they are asymptomatic and no lesions are visible through the colonoscope.

Adenoma↗
PubMed1991

Aggressive malignant hemangiopericytoma in the neck.

Hemangiopericytomas are rare vascular tumors, one fourth of which occur in the head and neck. These lesions are characteristically slow growing and slow to metastasize. We describe an otherwise healthy patient with a hemangiopericytoma on the left side of his neck that metastasized to his chest wall within 3 months after the tumor was first observed. The metastasis occurred while the patient was receiving radiation therapy. The patient died soon afterward. This case illustrates the aggressive malignant potential of hemangiopericytomas.

Head and Neck Neoplasms↗
PubMed1990

Plasmacytoma of the urethra treated with transurethral resection and radiotherapy.

Plasmacytoma, which is a localized malignant plasma cell tumor, occurs rarely and is found mostly in the upper airways of older patients. Two urethral plasmacytomas have been reported, 1 of which was a primary lesion. We describe a primary plasmacytoma of the urethra in a 23-year-old woman who had been exposed to diethylstilbestrol in utero. The patient underwent transurethral resection of the tumor and radiation therapy and has been free of disease for more than 10 years.

Adult↗
PubMed1990

Bacteriologic status of necrotic tissue in necrotizing pancreatitis.

To confirm the accuracy of guided percutaneous aspiration (GPA) in distinguishing sterile from infected pancreatic necrosis, we have performed Brown-Brenn tissue Gram stains on pancreatic and peripancreatic necrotic tissue removed operatively in 15 patients. In eight patients judged to have sterile necrosis on the basis of negative cultures of pancreatic exudate obtained first preoperatively (by GPA) and then intraoperatively, necrotic tissue debrided at surgery was also free of bacteria. In seven patients judged to have infected necrosis on the basis of positive cultures of pancreatic exudate obtained first preoperatively (by GPA) and then intraoperatively, necrotic tissue debrided at surgery harbored a considerable number of bacteria. We conclude that GPA targeted to areas of necrosis accurately distinguishes infected necrosis from sterile necrosis, and in infected necrosis, the solid necrotic tissue as well as the fluid component contains bacteria. We therefore believe that infected necrosis is not likely to be eradicated by catheter drainage and should be treated by surgical debridement.

Bacteriological Techniques↗
PubMed1990

Disseminated, nonmeningeal gastrointestinal cryptococcal infection in an HIV-negative patient.

Gastrointestinal cryptococcosis is extremely rare, especially in patients with no involvement of the central nervous system. We describe a 63-yr-old man undergoing prednisone therapy for chronic hepatitis and cirrhosis who presented with peritonitis, colitis, and skin lesions. Pathological studies revealed necrosis and numerous cryptococcal organisms in the colon, omentum, and skin, and cultures yielded Cryptococcus neoformans. The patient died of multisystem organ failure following emergency exploratory surgery performed when he had onset of symptoms of a bowel perforation after an endoscopic biopsy. Clinicians should be aware that gastrointestinal cryptococcosis can occur in the absence of infection of the central nervous system or lungs, and that it may affect relatively healthy patients who are immunocompromised because of splenectomy, chronic liver disease, or steroid therapy.

Colitis↗
PubMed1990

Supralevator abscess due to chronic rectal lymphogranuloma venereum.

Lymphogranuloma venereum (LGV) usually manifests as an inguinal syndrome, but it can also cause an anorectal syndrome that is difficult to diagnose because of its similarity to other disorders, the lack of easily available specific laboratory tests, and an assumption that it occurs only in women or homosexual men. LGV proctitis is often mild, but chronic cases can have serious complications. We describe a heterosexual Vietnamese man with a rectal stricture and supralevator abscess due to LGV proctitis whose presentation mimicked that of rectal cancer.

Abscess↗
PubMed1985

An unusual thyroid tumor: a comparison to a literature review of thyroid teratomas.

Presented is a patient with a tumor containing elements from two germ layers. It was associated within the patient's thyroid gland (located in a benign adenoma), but since the elements were widely separated from each other the tumor could not be classified as a teratoma or hamartoma. To our knowledge no similar tumor has been described. The interesting characteristics of this patient are described. The characteristics of this benign tumor are compared with those of cases in the literature of adult thyroid teratomas.

Adult↗
PubMed1983

Sclerosing orbital pseudotumor.

We report two patients who underwent orbital exploration yielding the diagnosis of sclerosing orbital pseudotumor. The presenting symptoms were exophthalmos, visual loss, abnormal ocular mobility, and ocular pain. Computed tomographic (CT) scans showed masses in the orbital apex. Steroids were ineffective. Orbital pseudotumor is a heterogeneous diagnostic category of lymphoid infiltrations of the orbit with a wide spectrum of pathological conditions and intraorbital locations. The clinical presentation typically includes the sudden onset of pain, diplopia, lid edema, and exophthalmos. Visual loss is uncommon. Most cases resolve spontaneously or respond to steroid treatment. Although fibrosis may be a prominent histological finding, the literature contains little information concerning its significance. We discuss the evidence for considering the sclerosing pseudotumors to be a significant variant with unique clinical behavior. Although features suggestive of pseudotumor were present in our case, the presence of visual loss and an apical mass shown on the CT scan led to the presumptive diagnosis of tumor and exploratory operation. Neurosurgeons should be aware of this entity as a cause of visual loss and orbital mass. Proper suspicion may in some cases permit transorbital biopsy and avoid craniotomy, inasmuch as operation is of no therapeutic benefit in this disease.

Adult↗