Biomedical subjects
S Duffy
Publications and source records attributed to S Duffy.
Risk factors for skin melanoma in Moscow.
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Immunoglobulin V gene expression in CD5 B-cell malignancies.
Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphomas (SLL) generally are malignancies of CD5 B cells. Immunophenotypic and clinicopathologic data, however, are required to distinguish subtypes that apparently have a different cytogenesis than that of conventional CLL or SLL. In addition to expressing CD5, neoplastic cells of the latter are also distinctive in that they frequently coexpress surface immunoglobulin (Ig), bearing one or more cross-reactive idiotypes (CRIs) (e.g. 17.109, G6,) that commonly are found on monoclonal IgM autoantibodies. The frequent occurrence of such CRIs reflects both the biased rearrangement and subsequent selected expression of Ig V genes with little or no somatic mutation. IgM/L CLL, for example, frequently (8/33) harbor abortive Ig rearrangements involving Humkv325, the VK gene encoding the 17.109-CRI. Also, the VH1 gene(s) encoding the G6 CRI accounts for over 10% of all VH genes and over 60% of all the VH1 genes used in randomly selected common CLL/SLL. Furthermore, comparison with the Ig expressed by nonmalignant G6 CRI+ B cells reveals an apparent restriction in the CDR3 of IgH expressed by G6 CRI+ CLL. Coupled with the observed potential bias in antibody light chain and heavy chain pairing in B-CLL, these data suggest that the autoantibodies expressed in this disease are selected based on antigen-binding activity. Collectively, our studies indicate that nonstochastic Ig V gene rearrangement and subsequent selection may influence the Ig repertoire expressed in this common B-cell malignancy.
Preliminary observations of holmium:YAG laser tissue interaction using human uterus.
Preliminary observations of a pulsed Ho:YAG laser on human uterine tissue in-vitro are presented. The tissue effect on the uterine myometrium was demonstrated using fresh uteri which had been subjected to laser energy. The laser crater and surrounding zone of thermal necrosis (ZTN) was quantified. Measurements demonstrated a consistent narrow ZTN (0.8-1.8 mm) irrespective of power or pulse frequency used. The percentage forward transmission of laser energy through 1 mm of myometrium was investigated using a pyroelectric detector and found to be 0.41%. Finally, a visible and measureable photoacoustic component to the Ho:YAG laser was demonstrated using a water bath and needle hydrophone.
Preliminary evaluation of a new high power diode laser.
A high-powered semiconductor diode laser (805 nm) has recently been developed for medical use. The laser-tissue interactions of this wavelength have been compared with Nd:YAG (1064 nm). When used in the contact mode, the extent of tissue vaporization and zones of thermal necrosis produced by these two lasers were similar. The diode laser was also an effective and haemostatic laser scalpel. This compact laser unit has potential advantages over existing Nd:YAG lasers.
Diet and colorectal cancer: results of two case-control studies in Russia.
Two case-control studies of diet and colorectal cancer were conducted in Moscow and Khabarovsk. The Moscow study comprised 100 cases of colorectal cancer and 100 neighbourhood controls. The Khabarovsk study consisted of 117 cases of colorectal cancer and 117 population controls. A history of the usual dietary intake one year prior to interview was taken using a food frequency questionnaire. Effects were adjusted in analysis for energy intake and education. Significantly reduced risks were observed with high intakes of cellulose (P = 0.001), beta-carotene (P = 0.002), vitamin C (P = 0.007), polyunsaturated fatty acids (PUFA) (P = 0.004), cholesterol (P = 0.04), and with a high ratio of PUFA to saturated fatty acids (SFA) (P = 0.002). Significant increases in risk were observed in association with high ratios of intakes of protein to cellulose (P = 0.002) and of fat to cellulose (P = 0.008). High intake of total fat was associated with non-significant decrease in the risk (P = 0.12), while high intake of SFA resulted in statistically non-significant increase in risk (P = 0.40). Significant reductions in risk were associated with high frequencies of consumption of vegetables (P = 0.001) and fruit (P = 0.009). There were results suggestive of a decreased risk with a high frequency of milk consumption (P = 0.06) and an increased risk in association with a ratio of meat to vegetable frequencies (P = 0.09). After adjustment among factors effecting risk of colorectal cancer statistically significant increase in the risk was seen only for protein/cellulose ratio and significant protective effect for PUFA/SFA ratio, beta-carotene and vegetable consumption.
In-vivo studies of uterine electrosurgery.
OBJECTIVE: To study the effects of electrosurgery on the living human uterus. DESIGN: Prospective observational study. SUBJECTS: Nine women with recurrent refractory dysfunctional uterine bleeding, listed for hysterectomy. INTERVENTION: Experimental endometrial resection on patients immediately prior to hysterectomy. MAIN OUTCOME MEASURES: The influence of power output, duration of exposure and repetition of consecutive surgical applications on the size of the zone of thermal necrosis in uterine tissue. RESULTS: Resection of the endometrium was associated with a narrow zone of thermal necrosis of between 0.69 and 0.76 mm which was not dependent on power output. Duration of exposure, however, was directly related to tissue necrosis (1.44 vs 1.88 mm for 1s and 5s, respectively). Coagulation by pin-point desiccation caused a zone of thermal necrosis of 3.30-3.77 mm that was independent of either power or duration of exposure to electrical energy. Thermal transmission through the uterus in situ, during electrosurgery was minimal, the maximum recorded rise in temperature from the baseline was 0.4 degrees C. The differences between the in vitro and in vivo effects of electrosurgery are highlighted and the possible reasons for these differences explored. CONCLUSIONS: The potential for unwanted thermally-induced damage to the uterus is small.
Reversible sensorimotor impairment following prolonged ventilation with isoflurane and vecuronium for acute severe asthma.
A patient with acute asthma developed severe sensorimotor neuropathy while being ventilated with isoflurane and receiving vecuronium and fentanyl. The neuropathy resolved spontaneously within three months of the episode. This unusual complication may result from prolonged use of inhalational anaesthesia or of vecuronium, or both.
Voltage-activated K+ currents in acutely isolated hippocampal astrocytes.
Hippocampal astrocytes were acutely isolated by papain treatment and mechanical trituration. Astrocytes were identified by their distinctive stellate morphology and immunocytochemical staining for glial fibrillary acidic protein. The electrophysiological properties of these cells were investigated using whole-cell voltage-clamp techniques. Three kinetically and pharmacologically distinct voltage-activated K+ currents were identified in most cells; they resembled the neuronal A-current, delayed rectifier, and inward rectifier. The activation threshold of the A-current was -40 mV with a time to peak that ranged from 10 msec at -20 mV to 6 msec at 100 mV. Steady-state inactivation was observed when the holding potential was positive to -100 mV. The current was half-inactivated at -60 mV and totally inactivated at -20 mV. The A-current was suppressed by 4-aminopyridine (4-AP). The delayed rectifier was activated by depolarizing pulses more positive than -40 mV and had a half time of activation that ranged from 18 msec at -20 mV to 10 msec at potentials more positive than 40 mV. This current did not inactivate during a 100 msec pulse and was suppressed by extracellular tetraethylammonium (TEA). An inwardly rectifying current was elicited by hyperpolarizing pulses more negative than -80 mV. This current was not blocked by extracellular TEA or 4-AP and was never observed in the presence of external Ba2+. Voltage-activated inward Na+ currents were never observed. Voltage-activated K+ channels may enhance the local K+ spatial buffering capabilities of the astrocyte syncytium when extracellular [K+] increases during neuronal activity.
Ethanol labeling: detection of early fluid absorption in endometrial resection.
A study is presented of ethanol labeling of irrigation fluid in endometrial resection. The introduction of ethanol labeling and intraoperative breath ethanol analysis provided an inexpensive and potentially useful means of detecting early fluid absorption during uterine surgery. The breath ethanol analyzer used was a hand-held meter; the irrigant solution was 5% dextrose with 1% ethanol. Simultaneous breath and venous samples were taken from women undergoing endometrial resection. An increase in breath ethanol was positively correlated with fluid absorption, blood ethanol, and serum glucose. This technique may prove valuable in preventing fluid overload during endometrial resection.
Gerontophilia--a case report.
Gerontophilia describes a specific sexual inclination towards the elderly and may at times explain the sadistic attacks made upon them. The case of a homosexual gerontophile who was engaging in assaulting old men is reported here. An attempt has been made at understanding his offending behaviour and possible treatment options proposed.
In vitro studies of uterine electrosurgery.
This study investigated electrosurgical techniques in vitro with emphasis on the tissue effects and heat transfer through full-thickness blocks of excised uterine tissue. Uterine morphometry was also examined. The 7-mm cutting resection loop was associated with a surrounding zone of thermal necrosis between 1.07-1.40 mm. There was no variation in this zone when power was altered, but a statistically significant increase was demonstrated with duration of exposure. A depth of destruction of 3.24-3.49 mm was possible with the desiccating coagulation technique, but fulguration achieved a depth of only 1.70-1.78 mm. A greater tissue effect was demonstrated as time intervals were increased. There was a fall-off in the measured rise in temperature with distance; at 4 mm from the active electrode, a mean rise of 4.5C was noted, whereas at 12 mm the mean temperature rise was 3.9C. There was a statistically significant increase in the mean temperature as power output in the cutting mode was increased. At 180 W, the mean rise was 2.0C but by 260 W, it was 3.9C. When the time interval was increased and the power held constant (220 W), a mean rise of 2.5C was recorded at 1 second, compared with 4.6C at 5 seconds, achieving statistical significance. Power increments in the coagulating mode did not alter the temperature profile, but increasing duration of exposure was associated with a significant rise in mean temperature (from 0.8 to 4.6C). A stepwise increase in the baseline temperature was noted with repetitive insults. The mean myometrial thickness of the anterior and posterior walls measured 1.8 and 1.9 cm, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Squamous cervical intraepithelial neoplasia: the role of laser treatment.
A review of the CO2 laser in the current management protocol for squamous cervical intraepithelial neoplasia (CIN) is presented. The laser provides the clinician with a versatile instrument that enables accurate application of biophysical insults to the full range of CIN lesions likely to be encountered. Side effects and cure rates compare favourably with the alternative methods of local destruction presently available. The final benchmark of success of all such treatments will remain the prevention of subsequent invasive cancer as observed on long-term follow-up. It should be noted that for some of the methods discussed such information is not yet available.
Malmö mammographic screening trial.
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Developmentally restricted immunoglobulin heavy chain variable region gene expressed at high frequency in chronic lymphocytic leukemia.
During fetal development, murine and human B-lineage cells rearrange and express a highly restricted set of immunoglobulin heavy chain variable region genes (VH genes). We noted that a VH gene of the restricted human fetal repertoire, designated 51p1, potentially could encode the VH region of two human IgM rheumatoid factor proteins. These rheumatoid factors share a cross-reactive idiotype (CRI) defined by reactivity with G6, a murine monoclonal antibody that recognizes an antibody heavy chain determinant present on many human IgM autoantibodies, particularly rheumatoid factors. Recently, we found that the G6 CRI also is expressed frequently by neoplastic CD5 (Leu1) B cells from patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma. However, neoplastic CD5-negative B cells from patients with lymphomas of follicular center cell origin rarely express this CRI. Here, we report that G6-reactive leukemic cells from two unrelated CLL patients express a VH gene that shares greater than 99% homology with a rearranged VH gene previously isolated from the leukemic cell DNA of another CLL patient and that is identical to VH 51p1. Using the polymerase chain reaction, we find that this VH gene is rearranged, and presumably expressed, in the genomic DNA of all examined cases of G6-reactive CLL or small lymphocytic lymphoma. Thus these data indicate that the autoantibody-associated G6 CRI is a serologic marker for a conserved and developmentally restricted VH1 gene that is expressed at high frequency in CD5 B-cell malignancies and early B-cell ontogeny.
The effects of fetal energy depletion on amniotic fluid concentrations of amino acids, organic acids and related metabolites.
Concentrations of amino and organic acids, phosphate, sulphate, gluconic acid and gluconolactone were measured in amniotic fluid samples which contained either normal or raised hypoxanthine concentrations. In this way, the effect of mild fetal ATP depletion could be determined. The effects of this mild asphyxia were to raise concentrations of phenylalanine, tyrosine, lysine, glycine, phosphate, sulphate, gluconic acid and glucono-1,5-lactone. However, concentrations of a variety of other metabolites were unchanged; thus no diagnostic confusion should arise with organic acidurias in mild asphyxia in contrast to the biochemical mimickry produced by severe asphyxia. Since clinically normal parturition can produce changes in amniotic fluid, urine from newborn or cord blood may not reflect the metabolic balance in utero.
Reference ranges for IgG subclasses in preschool children.
A normal range for IgG1, IgG2, and IgG3 subclasses has been established for children aged 6 months to 5 years using commercially available monoclonal antisera. Of particular interest were the very low concentrations of IgG2 in some healthy children, a finding which casts doubt on the importance of IgG2 deficiency reported in some patients with otherwise unexplained infections. It was not possible to construct a normal range for IgG4 values probably because these segregate into two populations in normal subjects.
Unusual presentation of chlamydial peritonitis: case report.
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