Biomedical subjects
Publications and source records attributed to C K Tang.
Anaplastic carcinoma of the urinary bladder, with oat cell-like components, is rare. We report such a tumor in a fifty-nine-year-old man, who died of rapidly disseminated carcinoma in one year despite postoperative radiotherapy and chemotherapy.
An adult rhabdomyoma was studied with the light and electron microscopes. The source of eosinophilia of the cytoplasm on light microscopy can be attributed to two components: a filamentous and a granular components. Ultrastructural studies displayed numerous banded myofilaments and mitochondria exhibiting varying degrees of abnormalities. These mitochondrial alterations were similar to those described in oncocytes and oncocytomas. The latter morphologic findings suggest that the mitochondrial abnormalities in adult rhabdomyomas represent an oncocytic change and that they are an integral part of the neoplastic process. Though primarily affecting epithelial cells, oncocytic change, may, under unusual circumstances, involve mesenchymal cells.
We report an unusual case of a polyp arising from ectopic gastric mucosa in the duodenum. The polyp demonstrated both hyperplastic and adenomatous proliferation. Adenomatous proliferation in a duodenal polyp arising from ectopic gastric mucosa is, to our knowledge, unique. The areas of adenomatous change were morphologically indistinguishable from those of adenomatous polyps arising in the stomach; hence, the adenomatous change observed in this polyp was regarded as a neoplastic process.
A duodenal tumor was found in a 68-year-old woman undergoing routine cholecystectomy for chronic cholecystitis associated with cholelithiasis. Microscopically, the tumor contained glandular structures and psammoma bodies. Electron microscopic examination demonstrated numerous intracytoplasmic neurosecretory granules consistent with endocrine D cells. Immunoperoxidase staining for somatostatin was positive in the tumor cells. The tumor appeared to be different from the somatostatinomas reported in the literature in that it was nonfunctional, located in the duodenum, and associated with psammoma bodies.
Four 11-week-old white Swiss Webster male mice were exposed to 2% enflurane in oxygen for 4 hr/day on 5 alternate days. Eight days later each male was mated with 2 females. There was a 20% loss of offspring due to stillbirths. A total of 24 pups survived (group E). At the age of 7 weeks the learning function of group E mice was tested in a Rosensweig maze and compared to that of 24 pups born to sires similarly exposed to oxygen alone (group C). Pups from group E performed statistically significantly slower than group C pups. After animals had been tested for 10 alternate days, there was no further change in performance in either group over the next 10 weeks. Thus changes of the reproductive cells of male mice caused by exposure to enflurane adversely affect the learning function of their offspring.
A first case of angiosarcoma of the vagina is described. Review of medical literature fails to show any documented cases of primary angiosarcoma of the vagina. Because of its rarity, no definite treatment could be suggested. The guideline for the management of this disease can only be drawn from several previously reported angiosarcomas of the uterus, cervix, and pelvis. It is recommended that a combined form of external irradiation and intracavitary brachytherapy be used after removal of the tumor.
Auto-tolerance and cross-tolerance to halothane, isoflurane and enflurane were tested on 36 mice divided into three equal groups. Each group was first exposed to increasing concentrations of either of the three anesthetics on 13 occasions. The concentration at which each mouse lost its righting reflex during successive exposures in a rotating cage was noted. Cross-tolerance was assessed by comparing the number of mice which had lost their righting reflexes during their first exposure to a given anaesthetic agent to the number which lost it after having been exposed to another anaesthetic. All animals developed auto-tolerance to halothane, isoflurane and enflurane. Cross-tolerance was noted only between mice exposed to isoflurane and enflurane and between mice exposed to halothane and subsequently anaesthetized with isoflurane, but not vice versa.
The iron ore tailings located on the coastal area of Tolo Harbour impose severe pollution problems to the environment. Two grass species, Paspalum distichum and Sporobolus virginicus, were found extensively on the excavated tailings, with the former found in waterlogged areas and the latter in dry areas. These plants may have a potential use in reclaiming the tailings. The present experiment is aimed at studying the reclamation ability of the two local species. Samples of the grass species collected from the tailings were cultured in a series of concentrations of manganese, iron, and copper, separately. Heavy metal tolerance was found to be species specific. S. virginicus collected from the tailings had the higher index of tolerance (0.9) and ED50 (0.85 ppm) to copper whereas P. distichum had the higher index of tolerance and ED50 to manganese (0.98 and 9.2 ppm, respectively) and iron (0.66 and 41 ppm, respectively). Plants of the two species collected from uncontaminated sites showed low index of tolerance and ED50 values for all three metals.
Carcinoma arising from the common hepatic duct is unique in its clinical course and is difficult to manage due to its dismal prognosis. The case reported and the treatment reflected not only the highly selective process but also the innovation of the intracatheter brachytherapy technique available to date. Exploratory laparotomy appears essential to identify the extent of the tumor and localize the area for brachytherapy. Percutaneous transhepatic cholangiography and placements of the indwelling catheter should be reserved for non-surgical candidates whose long-term survival is limited. Review of pertinent literature also shows various roles of irradiation in the management of this disease. The potentials of intraoperative therapy, brachytherapy, external beam therapy and their combinations were examined to implement the future recommendation of the treatment.
The effect of halothane on prenatal development was assessed using the appearance of postnatal tolerance to the anesthetic and its effect on brain weight. Eighteen 3-month-old mice were repeatedly tested in a rotating cage for loss of righting reflex during exposure to increasing concentrations of halothane on 15 occasions to determine whether or not tolerance to halothane developed. Of these, nine mice were born to dams exposed for 30 min to 2% halothane on days 14 and 17 of gestation. The other nine mice (controls) were born to dams exposed to 100% oxygen for 30 min at the same stage of pregnancy. There was no significant difference in tolerance to halothane between the groups during the first nine days of repeated exposure to halothane. By the 13th and 15th days, however, mice exposed to halothane in utero became more tolerant to 1% halothane than did controls (P less than 0.025). In addition, the mean total brain weight of six 7-week-old mice exposed to 2% halothane in utero for 30 min on days 14 and 17 of gestation was found to be significantly less than the mean total brain weight of six control mice not exposed to halothane in utero (20.83 +/- 0.27 g and 23.07 +/- 0.51 g, respectively, P less than 0.0025). This difference occurred mainly in the brain stem rather than in the forebrain and cerebellum.
3-deaza-SIBA, a postulated analogue of S-adenosylhomocysteine, inhibited the IgE-mediated histamine release and blocked both the choline uptake by the rat basophilic leukemia cells and the incorporation of choline into phosphatidylcholine and lysophosphatidylcholine. Unlike inhibitors of methylation which inhibit only dextran- and IgE-mediated reactions, 3-deaza-SIBA also blocked the histamine release from mast cells induced by other secretagogues, such as compound 48/80, ionophore A23187, polymyxin B and ATP. 3-Deaza-SIBA may perturb membrane functions of basophilic leukemia cells and mast cells by inhibiting the biosynthesis of phosphatidylcholine via choline incorporation, the turnover of which is probably required for cellular degranulation and the release of histamine. Previous studies with 3-deaza-SIBA have been mainly interpreted in terms of its structural similarity to S-adenosylhomocysteine and its potential use as an inhibitor of methylation reactions. In light of our present findings, experiments utilizing 3-deaza-SIBA as a biochemical probe have to be carefully interpreted.
The clinicopathologic features of angiosarcomas of the uterus and ovary are described. Extensive review of world literature shows only eight reported cases of angiosarcoma arising in the uterus and two in the ovary. Clinically, both patients presented with nonspecific symptoms. The tumors were found at surgery, and confirmed as angiosarcomas on histologic examination. The ultrastructure of both tumors is also presented. The association with mucinous cystadenoma in the second tumor raises the possibility that this may be a mixed Mullerian tumor. Both tumors behaved in an aggressive fashion.
Twenty mice aged three to four months and trained to find food in a six compartment maze after a 24 hour fast, were divided into two equal groups. For just over one month the group which had received intraperitoneal meperidine 3 microgram.g-1 and promethazine 1.66 microgram.g-1 performed significantly slower than the group which had received intraperitoneal physiological saline. Because of this marked effect, it was decided to investigate the action of the drug combination on brain development and to assess whether it produced permanent retardation in learning function. The dams of a second group of 12 mice were, therefore, given either the same dose of drug combination or saline. At the age of seven weeks, the six pups born to dams which had received intramuscular saline and the six born to dams which were given intramuscular promethazine with meperidine performed equally well in a series of tests conducted in a T maze and in the six compartment maze after a 24 hour fast. In the T maze they had to distinguish between the presence of food provided in diminishing amounts or no food. In the six compartment maze they were tested with multiple maze pattern sequences. Meperidine and promethazine given during early labor does not permanently affect the learning function of the progeny of mice.
Three unusual primary neoplasms in the skin that occurred in elderly patients (64, 77, and 69 years of age) are presented. Two histologic components were found in each of the three neoplasms, one being small cell or oat cell-like carcinoma and the other squamous cell carcinoma. Study by electron microscopy revealed neurosecretory granules, though few, in the small cell component. The lack of clinical evidence of oat cell carcinoma elsewhere, the autopsy finding of two histologic components in one patient, and the findings by conventional and electron microscopy lead us to conclude that these three neoplasms are primary in the skin and of Merkel cell origin. We suggest further that small cell carcinoma of the skin represents a poorly differentiated counterpart of trabecular carcinoma. The spectrum of malignant Merkel cell neoplasm is, therefore, expanding. Two of our three patients died of their neoplasms 2 and 2 1/2 years, respectively, after the initial diagnosis.
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A distinctive, benign, spindle cell tumor of the breast is described. Three patients were men, the fourth a woman. Histologically, each tumor displayed islands of spindle or stellate cells embedded in a collagenous matrix. Within the female breast, the lesion was within the stroma, displacing but not including the epithelial elements. Ultrastructural study of two tumors revealed diverse populations composed of fibroblasts, myofibroblasts, smooth muscle cells, and undifferentiated mesenchymal cells. The relationship of these tumors to spindle cell lipomas is discussed. The lesions have all been clinically benign, and their recognition as such is important.
The authors present an angiosarcoma of the scrotum and penis. The disease occurred in a 61-year-old man with a long history of neurofibromatosis (von Recklinghausen's disease). The histologic and ultrastructural features are described. The authors speculate that the angiosarcoma, which developed in a location without histologic evidence of neurofibromatosis, possibly represents an expression of an abnormal genome in vascular tissue. The angiosarcoma responded to radiation therapy only temporarily, recurred after surgery, and did not respond to Adriamycin, dactinomycin or cis-platinum. The patient died three years after the onset of his angiosarcoma.
The humidity output of a circle system was raised to 28 mg H2O/l by the use of a modified rotating wick vaporizer placed in the center of the soda lime canister and coaxial inspiratory and expiratory limbs. Both the fresh gas inflow and the expired gases passed through the lime and reached a compartment below it. The bag/ventilator connector, bearing a pressure relief valve, opened on the lateral wall of that compartment. Gases returning to the inspiratory valve passed: (1) through a tube in the canister connecting the inferior compartment to the vaporizer above water level, (2) through the upper portion of the vaporizer and around the rotating wick, and (3) through a tube emerging from the top of the vaporizer to reach the inspiratory valve. Thus inspired gases were humidified by the rotating wick constantly replenishing its water content warmed by the reaction of neutralization. The use of coaxial inspiratory and expiratory limbs reduced water condensation outside the canister.