Role of iron and copper during benzene toxicity

Role of transition metal ions in expression of benzene toxicity has been suggested. Intraperitoneal administration of benzene to female albino rats daily for 10 days resulted in accumulation of iron in liver nuclei, without any change in copper content. Incubation of hydroquinone (HQ), one of the principal metabolites of benzene with rat liver nuclei resulted in formation of thiobarbituric acid reactive products (TBAR). However, presence of bathocuproine, a copper chelator and EDTA, an iron chelator caused significant inhibition of TBAR release. Thus, the present study revealed that iron accumulation and involvement of copper in nuclear damage induced by HQ.

Distribution of inhaled nitric oxide during sequential and continuous administration into the inspiratory limb of the ventilator

OBJECTIVES

The concentrations of nitric oxide (NO) in the ventilatory circuits and the patient's airways were compared between sequential (SQA) and continuous (CTA) administration during inspiratory limb delivery.

DESIGN

Prospective controlled study.

SETTING

14-bed Surgical Intensive Care Unit of a teaching University hospital.

PATIENTS AND PARTICIPANTS

Eleven patients with acute lung injury on mechanical ventilation and two healthy volunteers.

INTERVENTIONS

A prototype NO delivery device (Opti-NO) and César ventilator were set up in order to deliver 1, 3 and 6 parts per million (ppm) of NO into the bellows of a lung model in SQA and CTA. Using identical ventilatory and Opti-NO settings, NO was administered to the patients with acute lung injury.

MEASUREMENTS AND RESULTS

NO concentrations measured from the inspiratory limb [INSP-NOMeas] and the trachea [TRACH-NOMeas] using fast response chemiluminescence were compared between the lung model and the patients using controlled mechanical ventilation with a constant inspiratory flow. INSP-NOMeas were stable during SQA and fluctuated widely during CTA (fluctuation at 6 ppm = 61% in the lung model and 58 +/- 3% in patients). In patients, [TRACH-NOMeas] fluctuated widely during both modes (fluctuation at 6 ppm = 55 +/- 3% during SQA and 54 +/- 5% during CTA). The NO flow requirement was significantly lower during SQA than during CTA (74 +/- 0.5 vs 158 +/- 2.2 ml.min-1 to attain 6 ppm, p = 0.0001). INSP-NOMeas were close to the values predicted using a classical formula only during SQA (bias = -0.1 ppm, precision = +/-1 ppm during SQA; bias = 2.93 ppm and precision = +/-3.54 ppm during CTA). During SQA, INSP-NOMeas varied widely in healthy volunteers on pressure support ventilation.

CONCLUSIONS

CTA did not provide homogenous mixing of NO with the tidal volume and resulted in fluctuating INSP-NOMeas. In contrast, SQA delivered stable and predictable NO concentrations during controlled mechanical ventilation with a constant inspiratory flow and was economical compared to CTA. However, SQA did not provide stable and predictable NO concentrations during pressure support ventilation.

Permissive hypercapnia with and without expiratory washout in patients with severe acute respiratory distress syndrome

BACKGROUND

Permissive hypercapnia is a ventilatory strategy aimed at avoiding lung volutrauma in patients with severe acute respiratory distress syndrome (ARDS). Expiratory washout (EWO) is a modality of tracheal gas insufflation that enhances carbon dioxide removal during mechanical ventilation by reducing dead space. The goal of this prospective study was to determine the efficacy of EWO in reducing the partial pressure of carbon dioxide (PaCO2) in patients with severe ARDS treated using permissive hypercapnia.

METHODS

Seven critically ill patients with severe ARDS (lung injury severity score, 3.1 +/- 0.3) and no contraindications for permissive hypercapnia were studied. On the first day, hemodynamic and respiratory parameters were measured and the extent of lung hyperdensities was assessed using computed tomography. A positive end-expiratory pressure equal to the opening pressure identified on the pressure-volume curve was applied. Tidal volume was reduced until a plateau airway pressure of 25 cm H2O was reached. On the second day, after implementation of permissive hypercapnia, EWO was instituted at a flow of 15 l/min administered during the entire expiratory phase into the trachea through the proximal channel of an endotracheal tube using a ventilator equipped with a special flow generator. Cardiorespiratory parameters were studied under three conditions: permissive hypercapnia, permissive hypercapnia with EWO, and permissive hypercapnia.

RESULTS

During permissive hypercapnia, EWO decreased PaCO2 from 76 +/- 4 mmHg to 53 +/- 3 mmHg (-30%; P < 0.0001), increased pH from 7.20 +/- 0.03 to 7.34 +/- 0.04 (P < 0.0001), and increased PaO2 from 205 +/- 28 to 296 +/- 38 mmHg (P < 0.05). The reduction in PaCO2 was accompanied by an increase in end-inspiratory plateau pressure from 26 +/- 1 to 32 +/- 2 cm H2O (P = 0.001). Expiratory washout also decreased cardiac index from 4.6 +/- 0.4 to 3.7 +/- 0.3 l.min-1.m-2 (P < 0.01), mean pulmonary arterial pressure from 28 +/- 2 to 25 +/- 2 mmHg (P < 0.01), and true pulmonary shunt from 47 +/- 2 to 36 +/- 3% (P < 0.01).

CONCLUSIONS

Expiratory washout is an effective and easy-to-use ventilatory modality to reduce PaCO2 and increase pH during permissive hypercapnia. However, it significantly increases airway pressures and lung volume through expiratory flow limitation, reexposing some patients to a risk of lung volutrauma if the extrinsic positive end-expiratory pressure is not substantially reduced.

K A P study on HIV / AIDS among first year MBBS students

This Kap (Knowledge, Attitude, Practical) study was to assess the current level of knowledge among first year M.B.B.S. students about AIDS at the point of entry to medical course. One hundred and seventy-one students were given a pre-tested close ended questionnaire. Overall level of knowledge about AIDS was found to be 64.91%. Male students were found to have better knowledge regarding transmission and prevention of AIDS than female students. Misconceptions were found to exist regarding mode of transmission, prognosis and prevention. Awareness programmes should be initiated among M.B.B.S. students in the first year itself, so that, lacunae can be rectified.

Cutaneous manifestations of diabetes mellitus

87 patients including 64 males and 24 females with diabetes mellitus and skin diseases were studied. The skin manifestations were common during the fifth decade of life. Maturity onset diabetes had increased incidence of skin disease. Incidence of skin disease was common in early diabetes. Infections both bacterial and fungal were seen in majority of patients. Specific cutaneous markers and metabolic changes were rare and seen in long standing diabetes. Infections were the common problems which recurred subsequently.

Biological variation of total, free and percent free serum prostate specific antigen levels in screening volunteers

PURPOSE

We determined the biological variation of the total, free and percent free serum prostate specific antigen (PSA) in men 50 years old or older.

MATERIALS AND METHODS

Between July 1995 and February 1996 we studied 84 healthy men from our PSA screening study to determine biological variation by calculating the coefficients of variation of 3 PSA measurements on blood samples drawn from each subject 2 weeks apart.

RESULTS

The mean coefficients of variation for total, free and percent free serum PSA were 15, 17 and 14%, respectively. Age, total PSA and ejaculation were not confounding factors in this analysis (that is multivariate R2 less than 5% for all indexes).

CONCLUSIONS

There is a mean variation of approximately 15% in measurements of total, free and percent free PSA that does not appear to be significantly affected by age and total PSA level.

Flexible ureteroscopy: Washington University experience with the 9.3F and 7.5F flexible ureteroscopes

PURPOSE

Recent advances in the design of flexible ureteroscopes have resulted in smaller caliber instruments. We review our experience with the smaller flexible ureteroscopes, and compare the efficacy and efficiency of the newer 7.5F to the standard 9.3F flexible instruments.

MATERIALS AND METHODS

Between January 1991 and 1995, 69 male and 41 female patients (mean age 57 years, range 16 to 91) underwent 116 retrograde flexible ureteroscopic procedures for a variety of diagnostic and therapeutic indications. A 9.3F ureteroscope (group 1) was used in 71 patients and a 7.5F instrument (group 2) was used in 39.

RESULTS

Patients in group 2 received sedation analgesia significantly more often than those in group 1 (56 versus 35%, p = 0.04). Active dilation of the ureteral orifice was required less often in group 2 (22.5%) than in group 1 (58%, p < or = 0.05). The total success rate for stone management, and diagnosis and/or treatment of an upper urinary tract lesion was 98.3 and 100%, respectively, in group 1, and 90 and 100%, respectively, in group 2 (p = 0.17). Of the 71 patients in group 1, 17 (24%) were treated on an outpatient basis, compared to 14 of 39 (49%) in group 2 (p = 0.16). No intraoperative or postoperative major complications were encountered in either group. Group 2 required less postoperative analgesia (p = 0.05). No ureteral stricture occurred in either group at an average followup of 9.5 months postoperatively (range 2 to 35).

CONCLUSIONS

For ureteral and renal pathological conditions the 7.5F ureteroscope is as effective as the 9.3F instrument diagnostically and therapeutically. The 7.5F ureteroscope usually can be used with sedation analgesia. Also, the smaller 7.5F ureteroscope is associated with less need for active ureteral dilation, minimal postoperative discomfort and a brief hospital stay.

Vasoconstrictor infiltration in breast reduction surgery: is it harmful?

The efficacy of vasoconstrictor infiltration in reducing blood loss is well known. However, adrenaline infiltration is potentially harmful to tissues. The question of whether or not adrenaline infiltration is harmful in breast reduction surgery remains unanswered. We retrospectively reviewed the notes of 100 consecutive cases after bilateral breast reduction (n = 200 breasts) with preoperative infiltration of a vasoconstrictor solution (10 ml adrenaline 1:10,000, 20 ml lignocaine 1%, 70 ml saline 0.9%, resulting in an adrenaline concentration of 1:100,000), looking specifically at postoperative complications that could be secondary to adrenaline infiltration. Two breasts developed a 'haematoma'; both were of small volume. Six breasts developed a 'minimal wound' problem which involved the T-junction. 'Wound breakdown' was noted in five breasts and again involved the T-junction in most cases. 'Wound infection' occurred in eleven breasts. There was one case of partial 'nipple necrosis'. Complications occurred in 12.5% of breasts and 21% of patients. We feel that this complication rate is within acceptable limits.

Oxidized low density lipoprotein acts on endothelial cells in culture to enhance endothelin secretion and monocyte migration

Monocyte deposition on the endothelium is the initial step in atherogenesis. Oxidized low density lipoprotein (Ox-LDL) is involved in the development of the fatty streak which progresses to the atherosclerotic lesion. Our interest focussed on the question, does the endothelium react to Ox-LDL to produce humoral substances that might influence the migration of human blood monocytes? Chemotaxis of monocytes was assessed by the modified membrane-filter technique based on the Boyden chamber principle. Exposure of porcine aorta endothelial cells (ECs) to Ox-LDL (100 micrograms/ml) increased the directional migration of monocytes by 25% (p < 0.01) over that of ECs in the absence of Ox-LDL. Radioimmunoassay of the EC culture media revealed the presence of immunoreactive endothelin-1 (ir-ET-1). The endothelin converting enzyme inhibitor, phosphoramidone (10 microM), when incubated together with ECs and Ox-LDL, suppressed the synthesis of ir-ET-1 by 53% (p < 0.05) and the migration decreased by 12% (p < 0.05). Preincubation of monocytes with the ETA receptor-selective antagonist, BQ-123 (1 microM), followed by exposure to ECs plus Ox-LDL, lead to a decrease in their migration by 12% (p < 0.05) compared to monocytes not treated with BQ-123. These results show that Ox-LDL acts on ECs to enhance the synthesis of ir-ET-1 which in turn increases the directional migration of monocytes. Phosphoramidone decreased the synthesis of ir-ET-1 but migration was affected only modestly; monocyte ETA receptor blockade by BQ-123 also suppressed migration toward EC chemoattractants to a small extent. Both results suggest that in addition to ir-ET-1 other chemotactic factors are being released by the ECs; Ox-LDL appears to enhance their release or synthesis.

Serum selenium, plasma glutathione (GSH) and erythrocyte glutathione peroxidase (GSH-Px)-levels in asymptomatic versus symptomatic human immunodeficiency virus-1 (HIV-1)-infection

OBJECTIVES

Antioxidant defense status was investigated in HIV-infected patients by measuring serum selenium, erythrocyte glutathione peroxidase (GSH-Px) activity, plasma thiol (-SH) and glutathione (GSH) concentrations along with the assessment of the clinical stage and surrogate markers of HIV-disease.

DESIGN, SETTING AND SUBJECTS

Serum selenium levels were determined cross-sectionally in 104 sequentially selected HIV-infected patients (83 outpatients and 21 patients with ongoing AIDS defining events). The patients were classified into three stages of the disease, I, II and III according to the 1993 Centers For Disease Control (CDC) classification system for HIV-infection. GSH-Px activities, plasma SH and plasma GSH concentrations were determined in a subset of 24 patients at stage I and 12 patients at stage III with an active AIDS-defining disease.

RESULTS

Mean serum selenium levels were lower in CDC stage II (68.7 +/- 20.9 micrograms/l; P < 0.01; n = 34) and stage III (51.4 +/- 14.7 micrograms/l; P < 0.01; n = 37) HIV-infected patients than in healthy subjects (89.2 +/- 20.9 micrograms/l; n = 72) and stage I patients (82.3 +/- 20.5; microgram/l; n = 33). Serum selenium levels were positively correlated with CD4-count (r = 0.42; P < 0.001; n = 104) and inversely with levels of soluble tumor necrosis factor receptors type II (r = -0.58; P < 0.01; n = 35), neopterin (r = -0.5; P < 0.001; n = 80) and beta 2-microglobulin (r = -0.4; P < 0.001; n = 94). Hepatitis C virus (HCV) and HIV-coinfected patients at CDC stages I and II showed markedly lower selenium concentrations compared to HIV-infected patients without concomitant HCV-infection. Serum selenium and GSH-Px activity in hospitalized AIDS patients was significantly lower as compared to asymptomatic patients and healthy subjects, whereas plasma SH and GSH concentrations were lower in both, asymptomatic -and AIDS-patients, than in the controls.

CONCLUSION

The results show that stages I-III of HIV-disease are characterized by significant impairments of antioxidative defenses provided by selenium, GSH-Px, SH-groups and GSH.

Problems and priorities of plastic surgical waiting list initiative schemes: an audit

According to figures published by the College of Health, 34,837 patients were waiting for in-patient plastic surgery treatment nationwide in 1986. By 1989 this number had increased to 40,085--an increase of 15%. Out of this waiting list, nearly 2000 patients were waiting in Manchester in 1990. Increasing public concern over the length of surgical waiting lists forced the Government to allocate extra resources to reduce both waiting lists and waiting times. We have reviewed the extra work done on a waiting list initiative scheme in Manchester in one year, from 1 August 1990 to 31 July 1991. The waiting list was reduced by 932 patients in one year. The attendance rate of the patients for surgery was excellent and the patients in general were very grateful for having had the treatment. The problems associated with setting us such schemes are enormous and are discussed in detail, with alternative suggestions for preventing waiting lists from building up again in future.

Effect of canarypox virus (ALVAC)-mediated cytokine expression on murine prostate tumor growth

BACKGROUND

Canarypox virus, ALVAC, does not replicate in infected mammalian cells and has potential as a vector for gene therapy in the treatment of cancer.

PURPOSE

Recombinant viruses carrying DNA sequences encoding interleukin 2 (ALVAC-IL-2), interferon gamma (ALVAC-IFN gamma), tumor necrosis factor-alpha (ALVAC-TNF-alpha), or the co-stimulatory molecule B7-1 (ALVAC-B7-1) were investigated as agents for the treatment of a newly defined mouse prostate tumor model.

METHODS

RM-1 mouse prostate cancer cells, which are syngeneic (i.e., same genetic background) to C57BL/6 mice, were used. The expression of foreign gene products in vitro in infected RM-1 cells was measured by immunoprecipitation, bioassay, or flow cytometry. The effects of foreign gene product expression on RM-1 tumor cell growth in C57BL/6 mice were measured after subcutaneous injection (in the back) of 5 x 10(5) uninfected or infected cells; measurements included determinations of time to a measurable tumor size, tumor size as a function of time, and survival. The induction of protective immunity by uninfected and infected RM-1 cells was tested by injection of lethally irradiated (70 Gy) cells and subsequent challenge with uninfected cells. The generation of cytotoxic T cells was monitored by use of a 51Cr release assay. Severe combined immunodeficient (SCID) mice were used to determine whether T or B lymphocytes were involved in ALVAC vector-mediated antitumor responses. Data were analyzed by use of Pearson's modification of the chi-squared test and Kaplan-Meier survival methods. Reported P values are two-sided.

RESULTS

The level of foreign gene product expression in ALVAC-infected RM-1 cells was dependent on the multiplicity of virus infection used; a multiplicity of five viruses per infected cell was chosen for subsequent experiments. RM-1 tumor growth in C57BL/6 mice was not affected by tumor cell expression of IL-2 alone, IFN gamma alone, or B7-1 alone; however, expression of TNF-alpha alone significantly delayed tumor growth at early time points (compared with parental ALVAC-infected tumors, P = .0001 at day 21 and P = .037 at day 28). Tumor cell expression of both TNF-alpha and IL-2 completely inhibited tumor growth in 60%-100% of treated mice. No protection against subsequent tumor challenge was detected in mice previously exposed to RM-1 cells expressing both TNF-alpha and IL-2. Cytotoxic T-lymphocyte activity toward RM-1 cells was not observed in C57BL/6 mice that rejected tumors. Tumor cell expression of TNF-alpha and IL-2 also resulted in tumor growth inhibition in SCID mice.

CONCLUSIONS

RM-1 mouse prostate cancer cells are readily infected by ALVAC vectors, and foreign gene products are efficiently expressed. Inhibition of RM-1 tumor growth by tumor cell expression of TNF-alpha and IL-2 appears to involve nonspecific antitumor activity.

The impact of systematic prostate biopsy on prostate cancer incidence in men with symptomatic benign prostatic hyperplasia undergoing transurethral resection of the prostate

PURPOSE

We determined the impact of 1 or more systematic (4 to 6 cores) needle biopsies of the prostate on the incidence of prostate cancer in men undergoing transurethral resection of the prostate for symptomatic benign prostatic hyperplasia (BPH) with elevated serum prostate specific antigen (PSA) and/or suspicious digital rectal examination.

MATERIALS AND METHODS

Records were reviewed retrospectively for 85 consecutive men 54 to 85 years old who underwent transurethral resection of the prostate for symptomatic BPH. Of the men 56 (66%) had at least 1 prior benign systematic prostate biopsy.

RESULTS

Cancer was detected in the transurethral resection specimen in 5 of 29 men (17.2%) who had no prior prostatic biopsy and in 9 of 56 (16.1%) who had at least 1 prior benign biopsy. Among the latter group the probability of cancer being present in the transurethral resection specimen was not related to the number of prior biopsies, PSA concentration or PSA density. Of the cancers detected in men with at least 1 prior benign biopsy 89% were clinical stage T1b or greater.

CONCLUSIONS

Clinically relevant prostate cancers may be detected in a significant proportion (more than 15%) of men undergoing transurethral resection of the prostate for symptomatic BPH despite prior screening with serum PSA, digital rectal examination and 1 or more systematic needle biopsies of the prostate.

Effect of digital rectal examination and needle biopsy on serum total and percentage of free prostate specific antigen levels

PURPOSE

We determined the effect of digital rectal examination and prostatic biopsy on serum total and free prostate specific antigen (PSA) concentrations in men undergoing screening for prostate cancer.

MATERIALS AND METHODS

In 93 men recruited from our PSA screening program we measured the serum concentrations of total and free PSA on 3 occasions during a 30-day interval before performing digital rectal examination. Total and free PSA measurements were repeated 1 and 24 hours after the rectal examination. Serum total and free PSA also was measured immediately before, and 1 hour, 24 hours and 1 week after prostatic biopsy in 30 men.

RESULTS

Biological variation for total and free PSA was 14.7 and 14.0%, respectively. At 1 hour after rectal examination total and free PSA increased by more than the biological variation in 31 and 48% of the men, respectively. Increases were significantly greater in men whose initial PSA concentrations were less than 4.0 ng./ml. There was a dramatic increase in total and percentage of free PSA in all men 1 hour after prostatic biopsy. Increases in percentage of free PSA were greater in men whose biopsies revealed cancer. Total PSA remained elevated for at least 1 week in most men, while percentage of free PSA returned to within or less than the biological variation of the baseline level in 90% of the men by 24 hours.

CONCLUSIONS

Digital rectal examination causes a modest increase in total and percentage of free PSA. Prostate needle biopsy causes more dramatic increases in both forms of PSA. Free PSA is preferentially released into the serum after prostatic manipulation and appears to be cleared more rapidly than complexed PSA. The differential return of the different PSA forms to baseline levels after biopsy could affect the use of measurements of the percentage of free PSA in clinical practice.

Serum selenium versus lymphocyte subsets and markers of disease progression and inflammatory response in human immunodeficiency virus-1 infection

Serum selenium levels were determined cross-sectionally in 57 HIV-infected patients who were classified according to the Centers for Disease Control (CDC) 1993 classification system. Mean serum selenium levels were lower in CDC stage II (58.7 +/- 12.2 micrograms/L; p < 0.01; n = 18) and stage III (47.6 +/- 11.3 micrograms/L; p < 0.01; n = 19) HIV-infected patients, than in healthy subjects (80.6 +/- 9.6 micrograms/L; n = 48) and stage I patients (73.6 +/- 16.5 micrograms/L; n = 20). Serum selenium levels were positively correlated with CD4 count, CD4/8 ratio, hematocrit, and serum albumin (r = 0.42; r = 0.39; r = 0.48; and r = 0.45; p < 0.01, respectively) and inversely with serum levels of thymidine kinase (r = -0.49; p < 0.01; n = 49) and beta 2-microglobulin (r = -0.46; p < 0.001; n = 49). In addition, serum selenium levels in 20 randomly selected AIDS-free individuals (CDC I: n = 10; CDC II: n = 10) were inversely correlated with serum concentrations of interleukin-8 (IL-8) and soluble tumor necrosis factor receptors (sTNFR) types I and II. There was no correlation with serum immuneglobulin A and total serum protein levels. The results show that the progressive deprivation of serum selenium in HIV-infection is associated with loss of CD(4+)-cells and with increased levels of markers of disease progression and inflammatory response.

Combined finasteride and flutamide therapy in men with advanced prostate cancer

OBJECTIVES

To evaluate the efficacy of combined finasteride and flutamide therapy in men with advanced prostate cancer by determining (1) the short-term tolerability of finasteride monotherapy and its effect on serum prostate-specific antigen (PSA) and hormone (testosterone, dihydrotestosterone) levels, and (2) the effects of the addition of flutamide on tolerability and on serum PSA and hormone levels.

METHODS

Thirteen hormone-naive men with advanced prostate cancer (4 with Stage D2, 1 with Stage D1, 1 with Stage D0, and 7 with rising PSA levels after radical prostatectomy [n = 2] or definitive radiation therapy [n = 5]) were initially treated with 5 mg finasteride daily. Flutamide (250 mg three times a day) was added after serum PSA levels stabilized.

RESULTS

Finasteride alone (median 5 weeks) had no significant effect on serum PSA levels (P > 0.05). Combined finasteride and flutamide resulted in a mean 91% reduction in serum PSA levels, with 85% of men achieving a nadir serum PSA level of less than 4.0 ng/mL and 46% achieving undetectable levels (0.2 ng/mL or less). Finasteride alone had no significant effect on serum testosterone levels (P > 0.05) but did result in a mean 74% reduction in serum dihydrotestosterone levels. Combined finasteride and flutamide resulted in a mean 56% increase in serum testosterone levels but had no additional effect on serum dihydrotestosterone levels (P > 0.05). Side effects occurred in 85% (gynecomastia or breast tenderness in 62% [8 of 13] and diarrhea in 23% [3 of 13]) of men on combined therapy. Potency was preserved in 66%. Combined finasteride and flutamide therapy was withdrawn from 15% (2 of 13) because of flutamide-induced diarrhea and from 23% (3 of 13) because of disease progression. All remaining patients (8 of 13) have serum PSA levels below 4.0 ng/mL and 4 of these 8 have undetectable levels. These men have received combined finasteride and flutamide for a median 11 months (range 6 to 19).

CONCLUSIONS

Finasteride monotherapy is inadequate therapy for advanced prostate cancer, but combined finasteride and flutamide may be a reasonable alternative for men with advanced prostate cancer who refuse conventional hormone therapy.

Acucise endopyelotomy: assessment of long-term durability

PURPOSE

We evaluated the long-term efficacy of Acucise endopyelotomy.

MATERIALS AND METHODS

A total of 28 patients with 28 ureteropelvic junction obstructions was reevaluated 2 or more years after Acucise endopyelotomy (mean 32.5 months). Subjective analysis was done with analog pain scales and objective analysis was performed with diuretic renal scintigraphy.

RESULTS

Subjective followup was available for all 28 patients, and 17 (61%) had a favorable response with 36% totally free of pain and 25% markedly improved. Among 26 patients with objective followup (93%) 21 (81%) had a patient ureteropelvic junction based on a diuretic renal scan with a half-time of less than 10 minutes or a normal Whitaker test. Among all regularly followed patients failure occurred uniformly within 1 year.

CONCLUSIONS

Acucise endopyelotomy is an effective and durable method for treating ureteropelvic junction obstruction.

The design of an inhibitor using alpha, beta-dehydro residues

X-ray crystallography and NMR spectroscopic studies on peptides containing alpha, beta-unsaturated (dehydro) residues have indicated that the steric effects caused by the dehydro residue are strong and predictable, and such residues can be used to generate specific peptide structures. In particular, dehydro-Alanine (delta Ala) is found to adopt an extended conformation and also induces a definite conformation in the neighboring saturated residue. In order to design a sequence that would fold into a known three-dimensional structure, we have undertaken a systematic theoretical study of the preferred conformations of tetrapeptide sequences of the type N-Ac-delta Ala-X-delta Ala-NHCH3 (x = Gly, L-Ala, L-Val, L-Leu, L-Lys, L-Arg, L-Phe). The methodology and parameters used have been standardized against sequences with known crystal structures. In all the sequences a consistent folding pattern is observed in which the delta Ala residues are in an extended conformation with phi approximately 140 degrees and psi approximately -40 degrees. The results are used to predict a sequence which has a structure very similar to that of the binding loop region of the bovine pancreatic trypsin inhibitor (BPTI).

Induction of apoptosis and secondary necrosis in rat dorsal root ganglion cell cultures by oxidized low density lipoprotein

Neural cell degeneration underlies central and peripheral nervous system disorders. In this study we examined the influence of oxidized low density lipoprotein (Ox-LDL) on rat dorsal root ganglion (DRG) cells in culture. Methods used were cell morphology, lactate dehydrogenase (LDH) release, the TUNEL-reaction and DNA fragmentation. Exposure of DRG cells to Ox-LDL for 24 h led to elevation of LDH in the culture medium; short term exposure (4 h) induced apoptosis, evidenced by DNA fragmentation and a positive TUNEL-reaction. DRG cells modified LDL in the presence of Cu2+ to mildly oxidized and to a small extent to fully oxidized forms; these in situ-generated LDL oxidation products were strongly toxic. These results suggest that Ox-LDL is a neurotoxin; it initiates apoptotic cell injury which progresses to necrosis and cell death.

Release of aldehydic products from glutamate or deoxyuridine by delta-aminolevulinic acid in presence of copper ions

Glutamate or deoxyuridine in the presence of Cu2+ and delta-aminolevulinic acid (ALA) reaction resulted in the formation of thiobarbituric acid reactive compounds (TBAR), which was linear up to 2 hr. TBAR increased linearly with the increase of both ALA and copper ion concentration. Oxygen consumption was directly proportional to the concentration of formaldehyde perhaps formed by secondary oxidation of dimethyl sulfoxide. Addition of oxyradical scavengers in the reaction mixture resulted in the inhibition of TBAR formation.

Hydroxyapatite-coated hip prostheses: difficulties with revision in 4 cases

The introduction of hydroxyapatite ceramic (HAC) coating on hip implants in 1985 (Furlong and Osborn 1991) was hailed as a major advancement for fixation of uncemented protheses. A problem that is now becoming evident is the extraction of these securely fixed prostheses for purposes of revision. We report on 4 patients who have had HAC-coated protheses implanted (2 as revision procedures and 2 at primary hip replacement) who had either continuing pain or a proven infection, so that it became necessary to carry out a revision hip arthroplasty. The prostheses were well-fixed and difficult to remove. A transfemoral, longitudinal osteotomy was used in 3 cases.

Glutathionyl hydroquinone: a potent pro-oxidant and a possible toxic metabolite of benzene

Iron catalysed bleomycin (an antitumor antibiotic)-dependent degradation of DNA was investigated in the presence of glutathionyl hydroquinone (GHQ). DNA degradation was enhanced twelve-fold in the presence of iron and GHQ and three-fold in the presence of iron and glutathione (GSH) as compared to iron alone. The degradation of DNA was linear with the increase in concentration of GHQ or GSH keeping the iron, bleomycin and other factors constant. The presence of oxyradical scavengers, viz., thiourea, mannitol, albumin, superoxide dismutase, catalase and dimethyl sulfoxide caused significant inhibition of degradation of DNA by GHQ and iron. All the externally added GHQ to bone marrow cell lysate was completely demonstrable by the assay of iron-catalyzed bleomycin-dependent degradation of DNA. Superoxide radical generation was demonstrable during the incubation of GHQ. Thus, the present study revealed that GHQ is a potent pro-oxidant and this observation is significant in understanding the mechanism of benzene toxicity with the possibility of GHQ as one of the toxic metabolites of benzene.

A pH-dependent allosteric transition in Ascaris suum phosphofructokinase distinct from that observed with fructose 2,6-bisphosphate

Ascaris suum phosphofructokinase exhibits dramatic shifts in its circular dichroic spectra in the pH range 6 to 8. These shifts are quite distinct from those induced by the activators AMP and fructose 2,6-bisphosphate. Concomitant with these pH-induced spectral shifts, the enzyme also displays changes in its allosteric behavior. Inorganic ions such as K+, NH+4, SO4(2-), and PO4(3-) also cause CD-spectral shifts similar to those produced by a change in pH. Based on the evidence derived from gel filtration and sedimentation equilibrium studies, the observed CD-spectral shifts are interpreted as due to conformational changes in the enzyme tetramer rather than due to a change in its aggregation state. Further, since the pK value of 6.4 obtained from pH dependence of increase in ellipticity at 210 nm agrees very well with the pK value of 6.8 for the loss of ATP inhibition due to modification of a histidine residue (G. S. J. Rao, B. A. Wariso, P. F. Cook, and B. G. Harris (1987) J. Biol. Chem. 262, 14068-14073), it is concluded that a single histidine residue in the ATP-inhibitory site acts as a trigger for the structural changes accompanying ATP inhibition of the enzyme. This view is strongly supported by the observation that the enzyme desensitized to ATP inhibition by chemical modification of a histidine residue in the ATP-inhibitory site shows absolutely no change in its CD spectrum in the pH range 6 to 8. This study demonstrates that the mechanism of activation of phosphofructokinase at higher pH and by inorganic ions involves conformational transitions that are quite distinct from those induced by AMP and fructose 2,6-bisphosphate. A scheme is presented that incorporates all of the different states of the enzyme dependent upon effectors and pH.