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Biomedical subjects

T Chou

Publications and source records attributed to T Chou.

71 records · Page 4Linked to original sources

Prevalence of measles antibodies in hospital personnel.

A community outbreak of measles prompted a serologic survey of personnel in a hospital serving that community. Two hundred sixty-six personnel, primarily physicians (129) and nurses (100), voluntarily participated. Serum specimens were initially tested by the immunofluorescent antibody and enzyme-linked immunosorbent assay (EIA) methods. Specimens with negative results by either test were further examined using the hemagglutination inhibition and plaque neutralization (PN) methods. If EIA and PN results were negative, an individual was considered susceptible. Only one of the 98 participants born during or after 1957 and none of the 168 participants born before 1957 were serosusceptible. The low rate of serosusceptibility, in contrast to previous studies of young adults, appears attributable to the sensitivity of the testing methods used. Based on our experience, institutions considering a measles serologic testing and immunization program should expect to identify very few serosusceptible personnel, even among those born during or after 1957.

Adult↗

Differences in the effects of host suppression on the adoptive immunotherapy of subcutaneous and visceral tumors.

A syngeneic transplantable sarcoma induced in C57BL/6 mice, MCA 105, was used in studies to examine host suppression on the adoptive immunotherapy of established intradermal and experimentally induced pulmonary and hepatic metastases. Fresh immune splenocytes were generated from mice immunized to the MCA 105 tumor by a mixture of viable tumor cells and Corynebacterium parvum. The adoptive immunotherapy of intradermal MCA 105 tumor with immune cells required prior immunosuppression of the recipient by sublethal irradiation with 500 R or T-cell depletion. The effect of whole-body sublethal irradiation appeared to eliminate a systemic host suppression mechanism, since partialbody irradiation involving the tumor-bearing area did not permit successful immunotherapy. Host irradiation was not required to achieve successful immunotherapy of experimentally induced pulmonary or hepatic metastases. In nonirradiated recipients bearing both intradermal and pulmonary tumors, host suppression did not affect the function of transferred immune cells to induce regression of pulmonary metastases. Thus, suppression of adoptive immunotherapy appears to be relevant to tumors confined to the skin and subcutaneous tissue but not to tumor in visceral sites, such as the lung and liver.

Animals↗

Pseudomonas fluorescens bacteremia from blood transfusion.

In October 1980, two units of blood contaminated with Pseudomonas fluorescens caused septic transfusion reactions in two recipients at a Chicago hospital; one patient died. Both units had been purchased from the same blood center. Investigation at the blood center and at other hospitals it supplied revealed another fatal case of P. fluorescens sepsis that had occurred one year earlier. Despite extensive environmental culturing at the blood center, the source of P. fluorescens was not identified. However, comparison of the interval between collection and administration of contaminated and non-contaminated units indicated that prolonged storage was a risk factor that may have caused clustering of cases in one hospital. Laboratory studies showed that small inocula of P. fluorescens proliferated in refrigerated fresh whole blood and reached 10(6) to 10(7) colony-forming units per milliliter seven days after incubation. These data suggest that prolonged storage of blood may be an important risk factor for the development of transfusion-related sepsis.

Adult↗

Spread of a toxic-shock syndrome-associated strain of Staphylococcus aureus and measurement of antibodies to staphylococcal enterotoxin F.

A gentamicin-resistant isolate of Staphylococcus aureus producing staphylococcal enterotoxin F (SEF) was isolated from a burn unit nurse during three episodes of toxic-shock syndrome (TSS). The nurse's reciprocal titer of antibodies to SEF was less than or equal to 5 during the three episodes, and when the titer rose to 1,000 no further relapses occurred despite continued colonization. The unusual antibiotic susceptibility pattern of the organism enabled demonstration of its spread. During four months, 12 (41%) of 29 burn unit patients, three other burn unit nurses, and a household contact of the nurse with TSS became colonized. None, including two patients whose initial reciprocal titers were less than or equal to 5, developed TSS. This experience illustrates significant cross-transmission of a TSS-associated strain and a temporal association of antibodies to SEF with cessation of recurrences of TSS. Additional factors must explain why other individuals lacking antibodies to SEF did not develop TSS.

Adult↗

Role of sialyltransferase in hypercupraemia of non-Hodgkin's lymphoma.

Copper, ceruloplasmin and sialyltransferase activity were measured in serum of 25 patients with lymphoreticular malignancies, in an attempt to study the sialyltransferase activity and correlation if any with the activity of the disease and ceruloplasmin. All 3 parameters were elevated in active disease but no definite correlation between sialyltransferase activity and copper or ceruloplasmin could be found. We conclude that plasma sialyltransferase activity is increased in lymphomas.

Adult↗

Prevalence of gram-negative bacilli in nares and on hands of pharmacy personnel: lack of effect of occupational exposure to antibiotics.

Exposure to antibiotics alters host flora and facilitates colonization by gram-negative bacilli (GNB). This may be important among pharmacy personnel, who have frequent contact with antibiotics and who have sometimes been suspected of inadvertently introducing GNB into parenteral solutions during admixture. We evaluated the risk of colonization by GNB, especially by tribe Klebsielleae (TK) which can proliferate in intravenous fluids, by culturing the hands and nares of 98 pharmacy personnel and 56 control subjects. Four culture surveys of pharmacy personnel yielded mean isolation rates of 79 and 52% for GNB and TK, respectively, from hands and 12 and 6.7% for GNB and TK, respectively, from nares; these rates did not differ significantly from those for control subjects (P greater than 0.1). The frequency with which pharmacy personnel performed antibiotic admixture did not significantly affect the rate of isolation of GNB or TK (P greater than 0.2). No multiresistant strains were isolated, and susceptibility patterns were similar for GNB species from pharmacy personnel and controls. These data indicate that occupational exposure of pharmacy personnel to antibiotics is not of sufficient magnitude to increase rates of nasal colonization or hand contamination with GNB.

Anti-Bacterial Agents↗

Progression of Wenckebach type A-V block to high degree A-V block in aged man.

This case report describes a 60 years old male with Wenckebach A-V block which progressed to high degree A-V block. Syncope and dizzy attacks were attributed to high degree A-V block in the study of ambulatory ECG (Holter). Wenckebach point was low; 90 bpm when the right atrium was paced. At 140 bpm, 2:1 A-H block with intermittent alternating and high degree A-H block were induced. Furthermore, a very wide His potential was recorded during the electrophysiological study. He received a permanent pacemaking. Since Wenckebach type A-V block is usually regarded as benign, this case seems to be rare.

Atrioventricular Node↗

Nosocomial Legionnaires' disease caused by aerosolized tap water from respiratory devices.

Five cases of nosocomial Legionnaires' disease which occurred over a five-month period were retrospectively investigated. Chart review showed that during the two- to 10-day incubation period before the onset of illness, all of the patients inhaled aerosolized tap water from jet nebulizers (four patients) or from a portable room humidifier (one patient), and all received high dosages of corticosteroids or adrenocorticotropic hormone. Exposure to both factors was highly significant (P less than 0.000001) when compared with the rate of exposure in 69 control patients. Environmental cultures yielded Legionella pneumophila from tap water and from reservoirs of tap water-filled respiratory devices. The yield was highest from hot tap water, in which the free chlorine level was less than 0.05 parts per million. Thus, Legionnaires' disease may be caused by contaminated aerosols from respiratory devices, and the use of contaminated tap water in such devices represents a previously unrecognized hazard to which corticosteroid-treated patients should not be exposed.

Adrenal Cortex Hormones↗

The mechanism of ageing of phosphonylated acetylcholinesterase.

1. The extent of potential reactivation of organophosphate-inhibited acetylcholinesterase decreases with time, a phenomenon called ageing. Ageing is due to dealkylation of the alkoxyl group of the residue bound to the enzyme. The rate of ageing is proportional to the electron-donating capacity of the alkyl group. 2. The ageing of phosphophonylated cholinesterase cal also be demonstrated using a phrenic nerve-diaphragm preparation. The same relationship between the rate of ageing and the structure of the alkyl group was observed. 3. Ageing occurs much faster in electrically stimulated preparations than in resting preparations. This may be due to production of a more acidic environment for the enzyme at the active centre by the products of hydrolysis of the acetylcholine released by stimulation.

Acetylcholinesterase↗

Beneficial effects of penicillamine treatment on hereditary avian muscular dystrophy.

Hereditary muscular dystrophy in chickens of the New Hampshire strain was treated with penicillamine from the 9th day after hatching to the 425th day. The adult maintenance dose for males was 50 mg/kg per day and for females, 13-65 mg/kg per day. In avian dystrophy, deterioration of the muscle fibers is evidenced in the 2nd mo by an inability of the birds to rise after falling on their backs and by a progressive rigidity of the wings. The drug delayed the onset of symptoms and partially alleviated the debilitating aspects of the disease. Penicillamine produced three major improvements: (a) better righting ability when birds were placed on their backs; (b) greater wing flexibility; (c) and suppression of plasma creatine phosphokinase activity. The results are statistically analyzed and discussed in relationship to Duchenne dystrophy. Normal birds were not affected by penicillamine as judged by these parameters. The rationale for using penicillamine, a sulfhydryl compound with reducing properties, was (a) to attempt to protect essential thiol enzymes in the anabolic and glycolytic pathways against inactivation and (b) to prevent collagen cross-linking and deposition in muscle. Although the precise mechanism of drug action has not been determined. the possible role of penicillamine in mitigating the symptoms of genetic dystrophy in man is under consideration. Further, penicillamine may have a more generalized application i the prevention of contractures in a variety of neuromuscular disorders.

Animals↗

Treatment of advanced primary lung cancer associated with malignant pleural effusion by the combination of immunotherapy and chemotherapy.

Twelve patients with advanced primary lung cancers associated with malignant pleural effusion were treated with intrathoracic instillation of recombinant interleukin-2 with or without in-vitro-sensitized cells. Two cases achieved complete response, and 7 partial response. The adverse effects seen in the protocol were marginal, and the protocol was well-tolerated and feasible. Furthermore, 4 cases were treated with the combination of systemic chemotherapy and adoptive immunotherapy. Of these, 3 cases responded well to the therapy and have shown a complete response for more than 20 months, indicating that adoptive immunotherapy together with chemotherapy might be a beneficial treatment for advanced lung cancer patients.

Adenocarcinoma↗

Intrarectal hyperthermia of circumferential rectal cancer. Report of 2 cases.

An intrarectal microwave (2,450 MHz) applicator was designed for hyperthermia of rectal cancer. Combined treatment of hyperthermia and irradiation was applied in two selected cases. The lesions of case 1 regressed completely, but cancer cells were still present after treatment in case 2. Such hyperthermia is useful for other circumferential cancers such as those of the esophagus and biliary tract. Combined hyperthermia and irradiation are an effective means of achieving therapeutic gains.

Adult↗

Maintaining confidentiality in a look-back investigation of patients treated by a HIV-infected dentist.

The spread of human immunodeficiency virus (HIV) from a Florida dentist with acquired immunodeficiency syndrome (AIDS) to several of his patients has generated considerable concern about the risk of HIV transmission during dental treatment. Accordingly, self-reporting of HIV infection and subsequent AIDS by a dentist at our medical center prompted notification and testing of patients at risk. Key features of the notification and testing process were (a) only patients who had undergone procedures deemed to pose appreciable risk of exposure to the dentist's blood were notified, (b) the identity of the dentist was shielded by not including in notification letters any identifying information other than the name of the medical center, and (c) patients' blood specimens were tested promptly for HIV antibodies and results were reported immediately to each patient to minimize the period of anxiety. HIV antibody testing was requested by 41 of the 88 patients to whom notification letters were sent, and all 41 were HIV negative after having undergone 395 procedures by the HIV-infected dentist. Review of the 88 patients' medical and dental records showed that at least 77 had received treatment by other health care providers at the medical center so that they would not be able to ascertain which provider had HIV infection. None of the patients who were notified by the medical center subsequently queried the dentist concerning possible HIV infection. Our experience demonstrates that look-back investigations can be conducted by institutions in a manner that substantially protects the identity of health care workers with HIV infection, minimizes the number of patients discomfitted, and avoids excessive utilization of personnel time. Even greater protection of the identity of health care workers with HIV infection presumably can be achieved when notification is undertaken by a public health agency.

Confidentiality↗