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Biomedical subjects

M Chu

Publications and source records attributed to M Chu.

At least 91 records · Page 5Linked to original sources
PubMed1990

Disseminated dermal dendrocytomas. A new cutaneous fibrohistiocytic proliferative disorder?

A 77-year-old white woman presented with 1 1/2-year history of progressively enlarging cutaneous papules, nodules, and plaques, some of which had spontaneously regressed. Her past medical history included untreated chronic lymphocytic leukemia for 10 years' duration. Multiple skin biopsy specimens revealed a diffuse superficial and deep dermal spindle-cell infiltrate accompanied by occasional foamy round cells and multinucleated giant cells. The spindle-shaped cells were focally arranged in a storiform pattern with prominent fibrous stroma. The spindle-shaped cells stained positively for numerous macrophage markers including CD45, factor XIIIa, Leu M5, HLA-DR, CD4, and Leu M3, consistent with dermal dendrocytes. They were also positive for nonspecific esterase and acid phosphatase, which is typical of tissue macrophages. The spindle-shaped cells were negative for CD-1, S-100, and ATPase activity, thus excluding a Langerhans cell immunophenotype. Combining the clinical features, light microscopy, immunohistochemistry, and enzymatic analysis, this patient appears to represent a novel cutaneous fibrohistiocytic proliferative disorder that features large numbers of dermal dendrocytes.

Aged↗
PubMed1989

Lactase deficiency in Singapore-born and Canadian-born Chinese.

Seventy-three of 77 adult Singapore-born Chinese (95%) and 48 of 49 Canadian-born adult Chinese (98%) were demonstrated to be lactase deficient using the lactose breath hydrogen test. The similar prevalence of lactase deficiency in the Singapore- and the Canadian-born Chinese despite a larger estimated amount of daily milk ingestion in the Canadian-born Chinese (430 ml vs 157 ml) supports the concept that lactase deficiency, which is transmitted genetically, does not have an adaptable component related to the quantity of lactose ingested. When the lactose breath hydrogen test performed with a dose of 0.5 g/kg of lactose was compared with the test using a standard dose of 50 g of lactose, there was very little loss of sensitivity. In spite of the presence of lactase deficiency, only 32% of the Singapore subjects and 23% of the Canadian subjects had gastrointestinal symptoms when milk was ingested in the daily diet. Peak breath H2 was higher in females than males, but the difference was more significant in the Canadian cohort.

Adolescent↗
PubMed1987

Heterotransplantation of human prostatic tissue.

Pieces of human prostatic tissue (approximately 1 mm3) were encapsulated in XM-50 Amicon hollow fibers and either implanted into the testis of an adult male rat or placed in culture. The protein synthetic capacity of such tissue pieces removed 1-42 days later was monitored by TCA precipitation, SDS-PAGE, and autoradiography. The results showed that tissue pieces retained their functional protein synthetic elements after this procedure. A newly developed solid-phase enzyme immunoassay for human prostatic antigen (PA), described in this report, was used to monitor PA levels in the serum of the recipient host or culture media. In some instances PA was detected 1-2 weeks postimplantation, a result that implies maintenance of functional secretory elements in vivo. Finally, morphology of tissue pieces 1-2 weeks postimplantation sometimes showed the presence of ductal epithelia and stromal elements in distribution patterns typical of those seen in fresh biopsy samples. We conclude that the function and structure of prostatic tissue implanted intrastesticularly compares favorably with that maintained in conventional explant culture. As such, the hollow fiber method offers promise for a new way of monitoring hormonal and/or chemotherapy testing of human prostatic tissue.

Animals↗
PubMed1985

Functional comparison of recombinant interleukin 2 (IL-2) with IL-2-containing preparations derived from cultured cells.

Due to its purity and potential availability in large amounts, human recombinant interleukin 2 (IL-2) expressed in Escherichia coli is an important source of IL-2 for experimentation and possible therapy. To date, very few comparisons between the activity of recombinant IL-2 and conventional cell-derived preparations of IL-2 have been made. This is particularly important since the use of recombinant IL-2 may have some specific limitations. For example, recombinant IL-2 is not post-translationally modified as are cell-derived preparations. Lack of modifications such as glycosylation of threonine 3 may alter efficacy or stability. Comparative studies are necessary to demonstrate the efficacy, species specificity, and stability of recombinant IL-2. By comparing IL-2 activity of recombinant IL-2 to that of cell-derived IL-2, we have demonstrated that each of the preparations are equally active in several murine and human IL-2 proliferation assays and that IL-2 is the active moiety in these assays. In contrast to previous reports, we also show that recombinant IL-2 is sufficient to establish and maintain long-term cell lines. Additionally, by using "synthetic" recombinant IL-2 of defined protein sequence, we have demonstrated that this amino acid-defined structure is indeed responsible for the functions attributed to IL-2.

Animals↗
PubMed1981

A large group in a district general hospital.

This article describes a large group in a district general hospital serving a defined catchment area. Fifteen consecutive meetings were studied and three types of meeting were observed; manic meetings, depressed meetings and, thirdly more balanced meetings not dominated by any powerful affect. The main topics discussed in the meetings included depression, illness, anxieties about treatment or recurrence, doctors, bereavement, loneliness, religion, and death, the more medical subjects possibly reflecting the medical orientation of the treatment programme. The principal themes in this meeting differ from those described in therapeutic communities, when themes of violence, rejection, sexuality and dependence conflicts figure more prominently. In the setting of the district general hospital, the character of the meeting appeared to be largely determined by the composition of the ward at the time, and patients with affective disorders. by virtue of their powerful moods, often assumed a dominant role.

Affect↗
PubMed1979

Patellectomy: a clinical study and biomechanical evaluation.

This study presents a long-term follow-up and evaluation of a single technique of patellectomy involving a cruciform repair of the extensor mechanism. The techniques of evaluation, namely: clinical observation, instant center analysis and an acoustical method of cartilage evaluation provide a more thorough and objective basis for clinical study than previously reported. Cruciform repair produced results comparable to conventional methods of surgical repairs. Patellectomized knees function well in people with patellofemoral disease but not in those with panarticular disease. Patellectomy substantially alters normal joint mechanics as evidenced by persistent changes in instant center analysis. Degenerative changes caused by the patellectomy are progressive. In view of newer concepts of the function of the patella in normal joint mechanics and improved designs of total knee arthroplasty, the indications for patellectomy are now more questionable than ever before in the history of orthopedics.

Auscultation↗
PubMed1978

Pre- and postoperative uses of CEA.

CEA plasma levels obtained prior to definitive surgery in patients with colorectal cancer in our hands have predictive ability. An elevated CEA greater than 2.5 ng/ml recorded by our laboratory means an increased risk of subsequent local recurrence or of later metastatic disease. The question as to whether or not this is additive as a prognostic variable when tested against careful histopathological staging remains. As a monitor, CEA will detect recurrence. Again, the problem as to how accurate this is remains. If we use two consecutive elevations of plasma CEA greater than 2.5 ng/ml as a criteria, we encounter about 15% false positives which must be weighed against finding disease significantly earlier in about one-third of the patients followed. Our data for second-look procedures indicate clearly that when used in patients with an elevated CEA laparotomy may be useful and further studies showed the presence of disease in 11 of 14 patients with an elevation following surgery for two consecutive tests were greater than 2.5 ng/ml. Two were operable. The significance of these findings is described.

Carcinoembryonic Antigen↗
PubMed1975

Flash photolysis electron spin resonance studies of the electron acceptor species at low temperatures in photosystem I of spinach subchloroplast particles.

The light-induced electron spin resonance signals of Photosystem I spinach subchloroplast particles have been studied at approximately 6 degrees K. Using the technique of flash photolysis-electron spin resonance with actinic illumination at 647 nm, a kinetic analysis of the previously observed bound ferredoxin ESR signals was carried out. Signal I (P700+) exhibits a partial light-reversible behavior at 6 degrees K so it was expected that if the bound ferredoxin is the primary acceptor of Photosystem I, it should also exhibit a partial reversible behavior. However, none of the bound ferredoxin ESR signals showed any such light reversible behavior. A search to wider fields revealed two components which did exhibit the expected kinetic behavior. These components are very broad (about 80 G) and are centered at g equals to 1.75 and g equals to 2.07. These two components exhibit the expected characteristics of the primary electron acceptor. A model is presented to account for the reversible and irreversible photochemical changes in Photosystem I. The possible identity of the primary acceptor responsible for these two new components, is discussed in terms of the available information. The primary acceptor may be an iron-sulfur protein, but not of the type characteristic of the bound or water-soluble ferredoxins found so far in chloroplasts.

Chloroplasts↗
PubMed1975

A study of the temperature dependence of the electronic spectra of alkyl cobaloximes.

The temperature dependence of the electronic spectra of the alkyl-pyridinatocobaloximes in benzene solution was found to be due to an equilibrium existing between two forms proposed to be inner-sphere and outer-sphere coordination compounds. Evidence is presented to rule out the possibilites of equilibria with pentacoordinated or dimeric forms, as well as a form with the cobalt out of the plane of the dimethylglyoxime.

Magnetic Resonance Spectroscopy↗