Parity and risk of thyroid cancer: a nested case-control study of a nationwide Swedish cohort

The association between parity and risk of thyroid cancer was examined in a case-control study nested within a cohort of Swedish women born 1925-60. A total of 1,409 cases of thyroid cancer were compared with 7,019 age-matched controls. Odds ratios (OR) and 95 percent confidence intervals (CI) were calculated as estimates of relative risk. A weak association was found between parity and risk of thyroid cancer (OR for ever-parous women cf nulliparous was 1.1, CI = 1.0-1.3). For the subset of papillary cancers, there was a significantly increased risk (OR for ever-parous cf nulliparous = 1.3, CI = 1.0-1.6), and among women diagnosed at the age of 50 or older, there was a positive linear trend with increasing number of livebirths. Women during the first year after a livebirth had an increased risk of thyroid cancer compared with women who delivered 10 or more years before; this association was most prominent among uniparous women (OR = 2.5, CI = 1.1-5.9). An increased risk was also apparent for age over 20 years at livebirth (among uniparous women) and age over 25 years at last livebirth (among multiparous women). A negligible effect of parity on thyroid cancer risk was seen, but each livebirth may have a short-term and age-dependent promoting effect.

Analysis of 2-chloro-2'-deoxyadenosine in human blood plasma and urine by high-performance liquid chromatography using solid-phase extraction

A reversed-phase high-performance liquid chromatographic (HPLC) method for the simultaneous determination of a new and promising anticancer drug, 2-chloro-2'-deoxyadenosine (CdA), and its metabolite, 2-chloroadenine (CAde), in plasma and urine was developed. A solid-phase extraction procedure with guaneran as internal standard (IS) was used. Plasma (1 ml) or diluted urine (1/100) mixed with 1 ml of phosphate buffer (10 mM, pH 6.5) was applied on a C8 isolute cartridge, which was prewashed with acetonitrile and phosphate buffer. The cartridge was further washed with 2.5 ml of 1% acetonitrile/phosphate buffer and 2.5 ml of hexane/dichloromethane (50/50). The compounds were eluted from the cartridge with 2.5 ml 5% MeOH in ethyl acetate. Chromatographic separation was achieved on C18 column eluted isocratically with phosphate buffer (10 mM, pH 3.0) containing 11% MeOH and 7% acetonitrile, and ultraviolet (UV) detection at 265 nm. Recoveries of CdA and CAde at 100 nmol/L were 90.6 +/- 4.9 and 98.7 +/- 7.8%, respectively. Recovery of IS was 96.1 +/- 6.1% at 250 nmol/l. The inter- and intraday coefficients of variation (CV) were < 10% at different concentrations within the range 1-500 nmol/L for both substances. In plasma, limits of detection of CdA and CAde were 1 and 2 nmol/L, respectively. In urine, the limit of detection was 100 nmol/L for both compounds. Standard curves were linear up to 50 and 500 nmol/L for urine and plasma, respectively. The present method will be a useful tool for further investigations of the pharmacokinetics of CdA in patients treated with different routes of administration.

Sequence analysis of 16S rRNA from mycoplasmas by direct solid-phase DNA sequencing

Automated solid-phase DNA sequencing was used for determination of partial 16S ribosomal DNA sequences of mycoplasmas. The sequence information was used to establish phylogenetic relationships of 11 different mycoplasmas whose 16S rRNA sequences had not been determined earlier. A biotinylated fragment corresponding to positions 344 to 939 in the Escherichia coli sequence was generated by PCR. The PCR product was immobilized onto streptavidin-coated paramagnetic beads, and direct sequencing was performed in both directions. One previously unclassified avian mycoplasma was found to belong to the Mycoplasma lipophilum cluster of the hominis group. Microheterogeneities were discovered in the rRNA operons of Mycoplasma mycoides subsp. mycoides (SC type), confirming the existence of two different rRNA operons. The 16S rRNA sequence of M. mycoides subsp. capri was identical to that of M. mycoides subsp. mycoides (type SC), except that no microheterogeneities were revealed. Furthermore, automated solid-phase DNA sequencing was used to identify a mycoplasmal contamination of a cell culture as Mycoplasma hyorhinis, which proved to be very difficult by conventional methods. The results suggest that the direct solid-phase DNA sequencing procedure is a powerful tool for identification of mycoplasmas and is also useful in taxonomic studies.

Shot-gun sequencing strategy for long-range genome mapping: a pilot study

We have recently proposed a strategy for construction of long-range physical maps based on random sequencing of NotI linking and jumping clones. Here, we present results of sequence comparison between 168 NotI linking (100 of them were sequenced from both sides) and 81 chromosome 3-specific jumping clones. We were able to identify 14 NotI jumping clones (17%), each joined with two NotI linking clones. The average size of chromosomal jumps was about 650 kb. The assembled 42 NotI genomic fragments correspond to 12-15% of chromosome 3. These results demonstrate the value of random sequencing of NotI linking and jumping clones for genome mapping. This mapping proposal can be used for connecting physical and genetic maps of the human genome and will be a valuable supplement to YAC and cosmid library based mapping projects.

Prognostic factors and relapse patterns in early-stage cervical carcinoma after brachytherapy and radical hysterectomy

Patients with cervical carcinoma FIGO stage IB and IIA (n = 167) treated with brachytherapy, radical hysterectomy, and pelvic lymphadenectomy at the University Hospital of Uppsala were evaluated, and a multivariate analysis was performed to reveal clinical and histopathological variables of predictive value of recurrence. The 5-year survival rate was 90%. Nineteen patients developed recurrent disease (11%), 15 of whom died. Patient age, clinical stage, type, and histologic grade of tumor did not indicate an increased risk of recurrence. However, multiparity (3 children or more; relative risk, RR = 4.6), lymph node metastases (RR = 6.4), tumor size (RR = 5.1), and residual carcinoma in the hysterectomy specimen (RR = 3.4) were important predictive indicators of recurrence. The median interval from initial treatment to the diagnosis of recurrence was 15 months. The majority of recurrences occurred during the first 2 years after treatment (74%) and most of them had symptoms (84%). Only three patients with recurrence were diagnosed within our surveillance program. The data suggest that surveillance for recurrence can be made more cost efficient with a more individualized follow-up during the first 2 years after treatment, concentrating on the patients with high-risk factors such as large tumors, residual carcinoma after irradiation therapy, and/or lymph node metastases.

The use of ethanol-tagged mannitol in transurethral resection of the prostate does not alter the bleeding time in patients who absorb irrigation fluid

To increase patient safety ethanol tagging of irrigation fluid is practised at several hospitals in Sweden to detect absorption of irrigation fluid during transurethral prostatic resection. Using this method it is found that almost half of the patients undergoing transurethral prostatic resections absorb irrigation fluid to some extent. Patients absorbing irrigation fluid bleed more than others. The phenomenon has been blamed on the open veins and sinusoides. Further, these patients are older, have larger prostates and longer operating times. To exclude an effect of ethanol-tagged irrigation fluid on the skin bleeding time this was measured before and after the operation in 57 patients. In 18 (32%) 160-1760 ml of irrigation fluid was absorbed, and in 9 patients over 480 ml. No difference in skin bleeding time emerged between absorbers and non-absorbers, and absorbers showed no differences in bleeding time between preoperative and postoperative values. There was a slight but insignificant decrease in the skin bleeding time after the operation in both absorbers and non-absorbers.

NotI linking clones as a tool for joining physical and genetic maps of the human genome

To study the connection among NotI linking clones, CpG islands, and genes, the sequence surrounding 143 NotI sites was determined. These NotI linking clones were isolated from human chromosome 3-specific libraries and contain an average C + G content of 65%. These clones represent sequence-tagged sites that can be positioned onto chromosome maps and used for generating a long-range NotI map of the human genome. A majority (about 90%) of these clones contain transcribed sequences, as detected by Northern blot hybridization, providing an efficient link between physical and functional (genetic) maps. The GenBank nucleotide database was searched with sequences from these NotI linking clones. For many clones, homology was found to human and other vertebrate genes. About 20 clones contained various repeats in their sequences and may represent microsatellite loci. Most of these NotI linking clones therefore represent evolutionarily conserved DNA fragments and also can be used for comparative genome mapping of other mammalian species. In addition, approximately 20% of all sequenced human CpG island-containing genes and more than 12% of all well-characterized human genes were found to possess NotI restriction sites. This is at least 2-5 times more than has been previously estimated and suggests that NotI sites have a much stronger association with genes.

In vivo accumulation of etoposide in peripheral leukemic cells in patients treated for acute myeloblastic leukemia; relation to plasma concentrations and protein binding

Since etoposide interacts with the nuclear enzyme topoisomerase II, the drug concentrations in the malignant cells during chemotherapy may have clinical correlates. Plasma protein binding of etoposide is extensive (94%) and alterations of the non-proteinbound fraction affect pharmacokinetic behavior of the drug. The pharmacokinetics of etoposide was therefore studied in plasma, total and non-proteinbound concentrations, and in leukemic cells isolated from peripheral blood samples from 22 patients after the first dose of the induction treatment for acute myelocytic leukemia. Fourteen patients received 100 mg/m2 and eight patients 200 mg/m2 as a 1 h infusion. The mean area under the concentration versus time curve AUC(0-infinity) in plasma was at the lower dose level 78.4 +/- 29.1 (mean +/- S.D.) micrograms/ml x h and 201.0 +/- 56.5 micrograms/ml x h at the higher dose level. The fraction of non-proteinbound etoposide in plasma was 5.2 +/- 3.4 and 5.4 +/- 2.1% in the two treatment groups. AUC(0-16h) in leukemic cells was 8.4 +/- 8.7 and 22.4 +/- 12.1 micrograms/ml x h at the two dose levels, respectively. The cellular etoposide concentration was 12.1 +/- 7.9 and 14.7 +/- 5.1% of the plasma concentration at the end of the infusion. The interpatient variability in cellular drug levels was considerable and exceeded the variability in plasma concentrations. Cellular accumulation of etoposide could be important for treatment outcome.

On the interaction between cytosine arabinoside and etoposide in vivo and in vitro

Cytosine arabinoside (ara-C) and etoposide are often used in combination in the treatment of acute myelocytic leukemia (AML). The intracellular phosphorylation of ara-C to its 5'-triphosphate (ara-CTP) is a prerequisite for its cytotoxic effects. It has been shown in vitro that etoposide can impair the formation of ara-CTP in leukemia cells. The present study was undertaken in order to elucidate whether this interaction may be of clinical importance. Leukemia cells were isolated from 3 patients with acute myelocytic leukemia and incubated in medium (RPMI-1640) with or without 10% fetal calf serum or in human plasma. When the cells were incubated in RPMI-1640 with ara-C (10 mumol/l) and etoposide during 2 h, the formation of ara-CTP was decreased to 71 +/- 18 (mean +/- S.D.) and 30 +/- 15% of control at 1 and 10 micrograms/ml etoposide, respectively. When the cells were incubated in human plasma, the formation of ara-CTP was not influenced by the presence of etoposide (101 +/- 6 and 103 +/- 20% at 1 and 10 micrograms/ml etoposide). When incubated in RPMI supplemented with 10% fetal calf serum, the corresponding figures were 81 +/- 8 and 70 +/- 20%. Six patients with AML were therefore treated with ara-C 0.5 or 1.0 g/m2 as a 2-h infusion every 12 h and, during 1 h before the second ara-C infusion, 100 or 200 mg/m2 etoposide was administered. The median change in the AUC of cellular ara-CTP between the first and second ara-C dose was 0% (-37 to +21%). The corresponding median change in rate of accumulation of ara-CTP in leukemia cells was 12% (-26 to +110%). The concentration of etoposide in plasma during the ara-C infusion was 18.7 +/- 5.1 micrograms/ml while the non-protein bound etoposide was 0.73 +/- 0.34 micrograms/ml. Thus, despite exposure to higher etoposide concentrations in vivo than in vitro, no impairment of ara-CTP formation was seen in the patients. This corresponds to the results obtained when leukemic cells were incubated in plasma. It is concluded that the inhibition of ara-CTP formation by etoposide seen in vitro is offset by the high protein binding of etoposide in plasma (96%) and that etoposide does not impair the formation of ara-CTP in leukemia cells in vivo during treatment with standard-dose etoposide.

Solid phase DNA minisequencing by an enzymatic luminometric inorganic pyrophosphate detection assay

A solid phase DNA sequencing method for non-radioactive detection of single base changes without the need for electrophoresis is presented. The concept relies on the detection of DNA polymerase activity by an enzymatic luminometric inorganic pyrophosphate detection assay (P. Nyrén, 1987, Anal. Biochem. 167, 235-238). Immobilized DNA fragments amplified with the polymerase chain reaction are used as template. A detection primer is annealed in front of the mutation and four aliquots of this mixture are incubated with DNA polymerase and one of the four different dideoxynucleotides. The presence or absence of an incorporated dideoxynucleotide is thereafter monitored by the release of inorganic pyrophosphate during the following primer extension step. We show that the concept can be used for sequencing of single bases as well as stepwise analysis of several subsequent bases.

Reduced risk of hip fracture in women with endometrial cancer

The effect of excessive endogenous oestrogens on the risk of hip fracture was investigated in a population-based cohort of 2111 women with endometrial carcinoma who were followed up from age 50 years regarding the occurrence of a first hip fracture. Overall, 77 cases of hip fracture were observed, as against 120.8 expected, which meant a significantly reduced relative risk, standardized incidence ratio (SIR) = 0.6, 95% confidence interval (CI): 0.5-0.8. This possible protective effect was significant for cervical fractures, SIR = 0.6 (95% CI: 0.4-0.8), but not for trochanteric, SIR = 0.8 (95% CI: 0.5-1.1). Age at endometrial cancer diagnosis was not a determinant of the risk of hip fracture. A lowered relative risk was present regardless of age at diagnosis and persisted during the entire follow-up period and into advanced ages. A case-control analysis within the cohort, and based on medical record data, indicated that a higher weight might be associated with a greater protective effect, as compared with a lower weight. Exposure to exogenous oestrogens was infrequent and could not have explained the present results. We conclude that persistent influence of oestrogens, notably of endogenous origin, can reduce the risk of hip fractures, and that this protective effect may be long-lasting and extend to advanced ages.

On the biochemical modulation of 6-mercaptopurine by methotrexate in murine WEHI-3b leukemia cells in vitro

The chemicals 6-mercaptopurine (6-MP) and methotrexate (MTX) are the cornerstones in the maintenance treatment of acute lymphoblastic leukemia. The intracellular metabolism of 6-MP to 6-thioguanosine nucleotides (TGN) via 6-thioinosine 5'-monophosphate (TIMP) is crucial for its cytotoxic effect. MTX inhibits purine de novo synthesis and thereby increases the intracellular PRPP being a substrate for the phosphoribosylation of 6-MP to TIMP. Hypoxanthine has been shown to inhibit the uptake of 6-MP over the cell membrane and the phosphoribosylation of 6-MP to TIMP. We have previously shown that the conversion of TIMP to TGN decreases at 6-MP concentrations above 5 microM in vitro. The aim of the present study was therefore to investigate the effect of MTX increasing the PRPP and TIMP concentrations and of hypoxanthine decreasing the TIMP concentration on the formation of TGN from TIMP. Murine myelomonocytic leukemia cells (WEHI-3b) were treated with 6-MP in vitro. The drug concentration was kept constant by continuous addition of 6-MP during the experiment. With this technique, the concentration of TGN begins to decrease already at 6-MP concentrations above 2 microM. The addition of 0.2 microM MTX 6 h before 6-MP strongly inhibited the purine de novo synthesis, decreased the ATP, and increased the PRPP concentration 4-fold. The intracellular concentrations of TIMP and to a lesser extent TXMP also increased. The concentrations of the TGN were, however, basically unaffected by the preincubation with MTX. Simultaneous addition of 20-50 microM hypoxanthine and 6-MP decreased the accumulation of all cellular 6-MP metabolites. It is concluded that the synergistic cytotoxic effect of the combination of 6-MP and MTX is not based on biochemical modulation of the 6-MP metabolism by MTX.

Semi-automated solid-phase DNA sequencing

Increasing the efficiency of DNA sequencing necessitates the development of systems which reduce the need for manual operations by integrating template preparation, sequencing reactions, product separation and detection. A semi-automated system, whereby PCR-amplified biotinylated genomic or plasmid DNA is immobilized on streptavidin-coated magnetic beads, has been developed.

The use of a bladder pressure warning device during transurethral prostatic resection decreases absorption of irrigation fluid

During a period of 4 weeks 102 patients underwent transurethral prostatic resection (TURP). Of these, 50 were randomly allocated to the use of an intravesical pressure device which warned the surgeon at a pressure elevation of 1.5 kPa. Ethanol (1%) was used as a marker in the irrigation fluid (glycine 2.2%), and absorption of ethanol-tagged irrigation fluid was detected by measurements in the expired air. In 28 patients absorption took place (in 8 of the 50 patients equipped with the warning device and in 20 of the 52 without the device). The greatest absorption was seen in the group without the device. No differences were found between the groups with regard to age, resected mass, resection time, resection speed, or haemorrhage. Patients who absorbed irrigation fluid were slightly older and bled more, and the resected mass was larger. The use of a pressure warning device reduces the amount of irrigation fluid absorbed and the number of patients who absorb irrigation fluid, and minimises the risk of the TUR syndrome.

Determination of 2-chloro-2'-deoxyadenosine in human plasma

The first high performance liquid chromatographic method for determination of the plasma concentration of 2-chloro-2'-deoxyadenosine (CdA) in patients, which is significantly more sensitive than the previously used RIA method, is presented. CdA is a purine analogue with useful clinical activity against lymphoproliferative disorders and it has recently been found to be the single most active agent in the treatment of hairy cell leukaemia. Guaneran (6-nitroimidazol-6-thioguanine) was added to 1 mL plasma as the internal standard and CdA was extracted using ethyl acetate. A Perkin-Elmer C18, 3 mu, 8 cm column was used for the separation of CdA and the internal standard from endogenous compounds in the sample with a mixture of sodium phosphate buffer 10 mM, methanol and acetonitrile (85:10:5, pH = 3.0) as the mobile phase. The sensitivity of the method (1 nM) allows the determination of CdA in plasma 24 h after the administration of 0.14 mg/kg as a 2 h infusion.

Trends in thyroid cancer incidence in Sweden, 1958-1981, by histopathologic type

Time trends in the incidence of malignant neoplasms of the thyroid were examined for Sweden for the period 1958-81, 5,838 cases being studied. Autopsy-diagnosed cases were excluded. Mean annual changes in the age-standardized rates over this period were 1.9% and 1.2% for women and men, respectively, for all thyroid carcinomas combined; 4.9% and 2.1% for papillary carcinoma; 0.9% and 2.1% for follicular carcinoma; and -1.0% and -2.1% for anaplastic carcinoma. Age, period and cohort models were fitted. There was a progressive increase in papillary cancer incidence for cohorts born since 1919. This increase cannot be satisfactorily explained as an artefact of trends in classification, and probably reflects a real increase in incidence. A less marked increase was seen for follicular cancer, and there was a decline for cohorts born since 1939. While the risk of papillary and anaplastic carcinoma was lower in iodine-deficient areas, follicular cancer risk was twice as high in these areas, for men only. There was a steady decline of anaplastic cancer in both sexes after 1965, largely attributable to a decline in cohorts born since 1924.

Trends in endometrial cancer incidence and mortality in Sweden, 1960-84

Trends in incidence of and mortality from invasive endometrial cancer in Sweden in 1960-84 were analyzed. The study was based on virtually all 20,371 patients given this diagnosis and 4,887 patients who died of the disease in that period. Only minor changes occurred in age-standardized incidence in pre-menopausal women, in whom the rates declined consistently during the last 15 years, especially in the youngest age groups. Among post-menopausal women, an early increase was followed by stable rates in women over 60 and decreasing rates at ages 50-59 years. In contrast, mortality rates decreased consistently over the study period. Multivariate regression analyses indicated that birth cohort was a more important determinant of incidence and mortality than was time period. The relative risk of developing endometrial cancer increased by about 20 percent in women born around 1900 as compared with 1880, and by an additional 40 percent from the 1910 cohort to the maximum risk attained in those born around 1930. In successively younger birth cohorts, the risk markedly and continuously declined. These strong birth-cohort effects after 1910 may be reasonably explained by the change from the risk-increasing estrogen-only replacement therapy introduced in the 1960s to the less harmful use, starting about 10 years later, of combined estrogen-progestogen regimens; and further, by the protective exposure of a large proportion of pre-menopausal women to oral contraceptives. Mortality, however, decreased steadily in successive cohorts from those born in 1890, indicating that the increase in incidence was referable mainly to non-lethal cancers.

Use of immunogold cytochemistry to detect Mn(II)-dependent and lignin peroxidases in wood degraded by the white rot fungi Phanerochaete chrysosporium and Lentinula edodes

Using antibodies raised against Mn(II)-dependent peroxidase and transmission electron microscopy immunogold cytochemistry, the spatial distribution of Mn(II)-dependent peroxidase during degradation of wood and wood fragments by Phanerochaete chrysosporium and Lentinula edodes was studied. In P. chrysosporium, the enzyme was localized in peripheral regions of the fungal hyphae on the cell membrane, on membranes of vesicule-like structures, and on the cell wall. The cytoplasmic distribution of Mn(II)-dependent peroxidase appeared similar to that of lignin peroxidase, as determined by double immunogold labeling procedures and antibodies raised against lignin peroxidase. In wood blocks of Betula verrucosa degraded by P. chrysosporium and L. edodes, Mn(II)-dependent peroxidase was detected on all wood cell wall layers showing signs of decay, whether at early or advanced stages of attack. In particular, the enzyme was localized in zones of degradation produced within the S2 wood cell walls. These regions displayed a looser, more open fibrillar structure than unattacked wood cell walls and were readily penetrated by purified preparations of Mn(II)-dependent and lignin peroxidases. With L. edodes, Mn(II)-dependent peroxidase was found to accumulate in middle lamellar regions selectively degraded by the fungus. Mn(II)-dependent peroxidase diffusion into undecayed wood cell walls was not observed. Key words: Mn(II)-dependent peroxidase, Phanerochaete chrysosporium, Lentinula edodes, immunogold cytochemistry, white rot decay, transmission electron microscopy.

On the paradoxically concentration-dependent metabolism of 6-mercaptopurine in WEHI-3b murine leukemia cells

The intracellular metabolism of 6-mercaptopurine (6-MP) was studied in a murine leukemia cell line, WEHI-3b. Cells were incubated 3 to 24 h with 10 nM to 50 microM 6-MP. Nucleotides were extracted with perchloric acid, and the 6-thiopurine nucleotides were isolated on mercurial cellulose. The endogenous ribonucleotides in the perchloric acid extracts as well as 6-thiopurine nucleotides were separated and quantified with anion exchange high-performance liquid chromatography. The concentration of 6-thioinosinate (6-TIMP) and 6-thioxantinate (6-TXMP) increased with an increasing 6-MP dose. The concentration of the 6-thioguanosine nucleotides (6-TGN) increased with 6-MP concentrations between 10 nM and 1 microM. However, further increase in 6-MP concentration led to a decrease in the formation of 6-TGN. At 50 microM 6-MP, the concentration of 6-thioguanosine 5'-triphosphate was one fifth of that seen at 1 microM. The incorporation of 6-[35S]mercaptopurine into DNA was also slightly higher at 1 microM compared with 50 microM. The cytocidal effect on clonogenic cells was one log greater at 1 microM 6-MP compared with 50 microM 6-MP. The decrease of 6-TGN was accompanied not only by an increased 6-TIMP concentration but also by an inhibition of the purine de novo synthesis and consequently by a decrease of the cellular ATP concentration. The ATP concentration in the cells treated with 1 microM 6-MP could be reduced to the level seen in cells treated with 50 microM 6-MP by simultaneous incubation with 0.3 microM antimycin A. This decrease of ATP concentration was accompanied by a reduction of 6-TGN and to a lesser extent of 6-TXMP. These experiments suggest that the "self-limiting" phenomenon in the metabolism of 6-MP might be caused by a depletion of ATP by inhibition of purine de novo synthesis presumably by 6-TIMP.

Evaluation of extracorporeal shock wave lithotripsy without anesthesia using a Dornier HM3 lithotriptor without technical modifications

In 210 patients with urolithiasis extracorporeal shock wave lithotripsy was performed without regional, general or infiltration anesthesia by means of a technically unmodified Dornier HM3 lithotriptor. The stone burden varied from small ureteral stones to complete staghorn stones. All patients were given premedication with pethidine and diazepam, and a lidocaine-prilocaine-containing cream was applied on the skin at the entry site of the shock wave. Energy usually varied between 14 and 16 kv. More than 90% of the patients reported the pain to be at most of moderate intensity and acceptable. Less than 3% found the treatment unpleasant. The results were compared to those obtained in 250 patients treated with anesthesia according to the original procedure, with a generator voltage of 18 to 23 kv. The number of extracorporeal shock wave lithotripsy sessions for ureteral and large stones was somewhat higher with the low energy method than with the original procedure. However, the therapeutic result in terms of renal units without stones after 4 weeks was similar to that recorded for patients treated with the anesthesia method. According to these promising results we believe that extracorporeal shock wave lithotripsy without anesthesia in an unmodified Dornier HM3 lithotriptor can be performed successfully in a majority of patients and is an attractive alternative to other technical modifications of the equipment.