Nitrogen in Hydroponic Growing Medium of Tomato Affects the Demographic Parameters of Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae).

We evaluated the effects of different nitrogen levels (380, 310, 240, and 174 ppm) on the life history parameters of Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) on hydroponically cultured tomato plants. Our data show that there is a positive correlation between the nitrogen content and the demographic parameters, as the intrinsic rate of increase of T. vaporariorum was the lowest (0.059 ± 0.007 day(-1)) at 174 ppm and the highest (0.088 ± 0.005 day(-1)) at 380 ppm of nitrogen. The net reproduction rate (R 0), finite rate of increase (λ), and mean developmental time (T) were significantly influenced by the nitrogen levels. The mean longevity of males and females showed a positive relationship with the nitrogen level, ranging from 64.8 ± 3.96 to 76.3 ± 2.44 for males and 61.6 ± 5.35 to 71.2 ± 2.44 for females, observed in the lowest and highest nitrogen levels, respectively. The relationship between nitrogen fertilization and T. vaporariorum management on tomato crops is discussed.

Effect of oronasopharyngeal suction on arterial oxygen saturation in normal, term infants delivered vaginally: a prospective randomised controlled trial.

Oronasopharyngeal suction (ONPS) with a suction bulb at birth is a traditional practice in the initial management of healthy infants in Iran and many other countries. The purpose of this study was to compare the effects of oronasopharyngeal suction (ONPS) with those of no suction in normal, term newborns delivered vaginally. A total of 170 healthy term infants of first and single uncomplicated pregnancies, with clear amniotic fluid, vaginal delivery and cephalic presentation, enrolled in the trial during labour. Newborns were randomised into one of the two groups, according to the use of the ONPS procedure. Arterial oxygen saturation (SaO2) levels, heart rates, blood gases of umbilical cord and Apgar scores were determined. The mean SaO2 values over the first and fifth min of birth were similar in the two groups. The maximum time to reach SaO2 of ≥ 92% was shorter in the no suction group. There were no statistically significant differences in the mean of heart rates, respiratory rates and Apgar scores between the groups. Apgar scores at 5 and 10 min were between 8 and 10 for all infants, respectively. Newborns receiving suction showed a statistically significant, lower mean partial carbon dioxide pressure (PCO2) and a significantly higher partial oxygen pressure (PO2) of umbilical artery. Although the differences were statistically significant, these were not considered clinically significant because values remained within normal ranges. According to this study, ONPS is not recommended as a routine procedure in normal, term infants delivered vaginally.

Risk of gestational diabetes mellitus in patients undergoing assisted reproductive techniques.

OBJECTIVE: To compare the incidence of gestational diabetes mellitus (GDM) between pregnancies conceived spontaneously and pregnancies conceived following assisted reproductive technology (ART). STUDY DESIGN: This cross-sectional study evaluated the medical records of 215 women who conceived spontaneously and 145 women who conceived following ART from September 2011 to October 2012. Exclusion criteria were: polycystic ovary syndrome, maternal age ≥40 years, family history of diabetes in first-degree relatives, pre-pregnancy diabetes, glucose intolerance treated with hypoglycaemic agent (e.g. metformin), history of GDM, history of stillbirth, recurrent miscarriage, history of baby with birth weight ≥4kg (macrosomia), parity >3, Cushing syndrome, congenital adrenal hyperplasia and hypothyroidism. For better comparison of the incidence of GDM, the ART group was further subdivided into: (i) an in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) group (n=95); and (ii) an intrauterine insemination (IUI) group (n=50). The diagnosis of GDM was based on the criteria of the American Diabetes Association. RESULTS: The incidence of GDM was significantly higher in the IVF/ICSI and IUI groups (43% and 26%, respectively) compared with the spontaneous pregnancy group (10%). Age, pre-pregnancy body mass index (BMI) and weight gain in pregnancy were similar among women with GDM in all three groups. In addition, the incidence of pregnancy-induced hypertension was significantly higher in the IVF/ICSI group (21%) compared with the spontaneous pregnancy group (7%). Logistic regression analysis demonstrated four strong risk factors for GDM: age, BMI, mode of ART and progesterone use during pregnancy. CONCLUSION: This study indicated that the risk of GDM is two-fold higher in women with singleton pregnancies conceived following ART compared with women who conceived spontaneously. In addition, progesterone use during pregnancy was found to be an important risk factor for GDM. This subject requires further study.

Mechanisms of muscular electrophysiological and mitochondrial dysfunction following exposure to malathion, an organophosphorus pesticide.

Muscle dysfunction in acute organophosphorus (OP) poisoning is a cause of death in human. The present study was conducted to identify the mechanism of action of OP in terms of muscle mitochondrial dysfunction. Electromyography (EMG) was conducted on rats exposed to the acute oral dose of malathion (400 mg/kg) that could inhibit acetylcholinesterase activity up to 70%. The function of mitochondrial respiratory chain and the rate of production of reactive oxygen species (ROS) from intact mitochondria were measured. The bioenergetic pathways were studied by measurement of adenosine triphosphate (ATP), lactate, and glycogen. To identify mitochondrial-dependent apoptotic pathways, the messenger RNA (mRNA) expression of bax and bcl-2, protein expression of caspase-9, mitochondrial cytochrome c release, and DNA damage were measured. The EMG confirmed muscle weakness. The reduction in activity of mitochondrial complexes and muscular glycogen with an elevation of lactate was in association with impairment of cellular respiration. The reduction in mitochondrial proapoptotic stimuli is indicative of autophagic process inducing cytoprotective effects in the early stage of stress. Downregulation of apoptotic signaling may be due to reduction in ATP and ROS, and genotoxic potential of malathion. The maintenance of mitochondrial integrity by means of artificial electron donors and increasing exogenous ATP might prevent toxicity of OPs.

Obstetric and neonatal outcomes of twin pregnancies conceived by assisted reproductive technology compared with twin pregnancies conceived spontaneously: a prospective follow-up study.

OBJECTIVE: To compare the obstetric and neonatal outcomes of twin pregnancies conceived by assisted reproduction technology (ART) with spontaneously conceived (SC) twin pregnancies. STUDY DESIGN: A prospective cohort study compared all dichorionic twin pregnancies in nulliparous women following fresh in vitro fertilization/intra-cytoplasmic sperm injection (ICSI) or ICSI cycles at Royan Institute (n=320) with SC dichorionic twin pregnancies in nulliparous women at Arash Women's hospital (n=170) from January 2008 to October 2010. These pregnancies were followed-up until hospital discharge following delivery. Obstetric and neonatal outcomes of SC and ART twin pregnancies were compared. RESULTS: Multivariate analysis, adjusted for maternal age and body mass index, revealed that the obstetric outcomes were similar in both groups. However, the risks of very preterm birth [odds ratio (OR) 5.2, 95% confidence interval (CI) 2.1-12.9], extremely low birth weight (OR 2.2, 95% CI 1.0-3.9), admission to a neonatal intensive care unit (OR 2.0, 95% CI 1.2-3.2) and perinatal mortality (OR 2.3, 95% CI 1.2-4.0) were higher in the ART group. CONCLUSIONS: The maternal outcomes of ART dichorionic twins were comparable with those of SC twins. However, despite the same obstetric management, the rates of very preterm birth, extremely low birth weight, admission to a neonatal intensive care unit and perinatal mortality were significantly higher in the ART group.

The presence of amorpha-4, 11-diene synthase, a key enzyme in artemisinin production in ten Artemisia species.

BACKGROUND AND THE PURPOSE OF THE STUDY: Artemisinin is one of the most effective medicine against malaria, which is produced naturally by Artemisia annua in low yield. It is produced in a metabolic pathway, in which several genes and gene products are involved. One of the key genes in this pathway is am1, which encodes amorpha-4, 11-diene synthase (ADS), a key enzyme in artemisinin biosynthesis pathway. The aim of this study was to determine the presence of this gene in ten Artemisia species in order to increase the yield of production of Artemisinin. METHODS: The experiments were carried out using PCR. Specific primers were designed based on the published am1 gene sequence obtained from A. annua (NCBI, accession number AF327527). RESULTS: The amplification of this gene by the specific primers was considered as a positive sign for the potentiality of artemisinin production. Since the entire am1 gene was not amplified in any of the 10 species used, four parts of the gene, essential in ADS enzyme function, corresponding to a) pair site of Arg10-Pro12 in the first 100 amino acids, b) aspartate rich motif (DDXXD), c) active site final lid and d) active site including farnesyl diphosphate (FDP) ionization sites and catalytic site in the ADS enzyme, were investigated. MAJOR CONCLUSION: The sequence corresponding to ADS active site was amplified only in A. annua, A. aucheri and A. chamaemelifolia. The negative results obtained with other species could be due to some sequence alteration, such as point mutations or INDELs. We propose A. aucheri and A. chamaemelifolia as two potential candidate species for further characterization, breeding and transferring am1 gene for artemisinin overproduction.

The expression of p38, ERK1 and Bax proteins has increased during the treatment of newly diagnosed acute promyelocytic leukemia with arsenic trioxide.

BACKGROUND: Promising reports exist regarding the use of arsenic trioxide (ATO) as first-line treatment in acute promyelocytic leukemia (APL). Although the in vitro effect of ATO is extensively studied, the in vivo mechanism(s) of ATO action is mostly unknown. PATIENTS AND METHODS: Newly diagnosed APL patients were involved and received ATO (0.15 mg.kg/day) for 28 days as induction followed by consolidation therapy. Bone marrow (BM) aspirates were obtained on days 0, 14 and 28 of treatment for further molecular studies. Clinical findings and white blood cell counts were recorded as well. RESULTS: Complete remission was observed in 17 (85%) patients with the median duration of 28 days (18-38) and cumulative dosage of median 280 mg (180-350). Hyperleukocytosis and APL differentiation syndrome (63%), gastrointestinal disorders (30%), liver enzyme elevation and night sweating (50%) were the most prevalent side-effects. The expression of Bax, ERK1 and p38 proteins and caspase-3 activity increased significantly in promyelocytes of BM aspirates at days 14 and 28 of induction therapy. CONCLUSION(S): These findings point toward the role of p38 and Bax in the induction of apoptosis, which was confirmed by increase in caspase-3 activity. However, the increase in ERK1 expression with regard to leukocytosis could translate to a proliferative/differentiation effect.

Epidemiology of hospitalized female burns patients in a burn centre in Shiraz.

During 2000 to 2001, all 170 female burn patients admitted to the Ghotbeddin Burn Centre in Shiraz were studied to determine the epidemiological characteristics and outcome of burn for these patients. The overall mortality rate was 64%. The highest frequency of burns (53.5%) occurred among 16-25-year-olds. The commonest cause of burn was flame (98.2%). The mean (SD) length of hospital stay was 13 (14.3) days. Mean (SD) of total body surface area (TBSA) burned among all patients was 56% (28.5%); among those who survived it was 29% (13.4%) and among those who died it was 72% (21.7%). The relation between TBSA and mortality was statistically significant.

Micropropagation of Aloe vera L. grown in south Iran.

Aloe vera L. is a medicinal plant grown in different parts of the world. Several papers have reported the micropropagation of this plant and its response to different combinations of hormones. In this research, we used A. vera plants grown in south Iran. MS culture medium with twenty-three combinations of hormones were used, including some of those employed previously by other researchers. Ten media showed positive results and the best result was obtained using Kin (1 mg L(-1))+IAA (0.1 mg L(-1)) which has not been reported before. Produced plantlets rooted in free hormone MS medium and transferred into soil. The survival rate was 83%.

Epidemiology of hospitalized female burns patients in a burn centre in Shiraz

During 2000 to 2001, all 170 female burn patients admitted to the Ghotbeddin burn centre in Shiraz were studied to determine the epidemiological characteristics and outcome of burn for these patients. The overall mortality rate was 64%. The highest frequency of burns [53.5%] occurred among 16-25-year-olds. The commonest cause of burn was flame [98.2%]. The mean [SD] length of hospital stay was 13 [14.3] days. Mean [SD] of total body surface area [TBSA] burned among all patients was 56% [28.5%]; among those who survived it was 29% [13.4%] and among those who died it was 72% [21.7%]. The relation between TBSA and mortality was statistically significant

Does pre-transplantation antireflux surgery eliminate post-renal transplantation pyelonephritis in children?

PURPOSE: Antireflux surgery for VUR before renal transplantation decreases the risk of post-kidney transplant UTI in pediatric patients with primary vesicoureteral reflux. We studied the risk of post-kidney transplant UTI in patients with or without surgical correction of VUR before transplantation compared to patients without VUR. MATERIALS AND METHODS: We compared 12 patients who had VUR corrected before transplantation (group 1) to 17 patients with VUR who did not undergo antireflux surgery before transplantation (group 2) and 36 patients undergoing renal transplantation without VUR (group 3). A total of 10 patients in group 1 (83.3%) and 10 in group 2 (58.8%) had high grade VUR. RESULTS: Eight patients in group 1 (66.7%), 6 in group 2 (35.3%) and 33 in group 3 (91.7%) remained free of febrile UTI during followup (p = 0.00). Among patients with high grade VUR 6 in group 1 and 1 in group 2 remained UTI-free (p = 0.02). A total of 33 patients in the control group (91.7%) remained free of febrile UTI, an incidence that was significantly lower compared to group 1 (p = 0.03) and group 2 (p = 0.00). Of the patients with high grade VUR 3 in group 1 (30%) and 4 in group 2 (40%) experienced recurrent febrile UTIs (p = 0.64). CONCLUSIONS: Even after surgical correction of VUR before transplantation the frequency of febrile UTI remained higher than that in kidney transplant recipients without VUR. In cases of high grade VUR reimplantation before renal transplantation decreased the rate of febrile UTI but it was still higher than the level of risk in the control group.

Treatment of acute promyelocytic leukemia with arsenic trioxide without ATRA and/or chemotherapy.

INTRODUCTION: Arsenic trioxide is effective and approved for treatment of relapsed or refractory acute promyelocytic leukemia (APL) cases resistant to all-trans retinoic acid (ATRA), but its effect on new cases of APL is not clear. MATERIALS AND METHODS: We studied 111 patients with APL. Arsenic trioxide was infused at 0.15 mg/kg daily dose, until complete remission was achieved. Then, after 28 days of rest, arsenic trioxide was infused daily for 28 days as consolidation therapy. We studied minimal residual disease (MRD) by semi-sensitive reverse transcription polymerase chain reaction (RT-PCR) on peripheral blood samples. RESULTS: Complete remission was observed in 95 patients (85.6%). With the median (range) follow-up period of 16.5 (1-57) months, 1- and 2-year disease-free survival was 88.3% and 63.7%, respectively; 24 patients relapsed, 19 of whom achieved a second complete remission, again by arsenic trioxide. Third and fourth remissions were seen in some relapsed patients, again by arsenic trioxide. For patients in complete remission, 1- and 3-year survival was 95.5% and 87.6%, respectively. MRD was positive in four (8.3%) out of 48 cases during 1 year after remission induction; three of them relapsed clinically. CONCLUSIONS: Arsenic trioxide is effective as first-line treatment for APL. Results of arsenic trioxide combination therapy with chemotherapy/ATRA requires further study.

Evolutionarily conserved sequences on human chromosome 21.

Comparison of human sequences with the DNA of other mammals is an excellent means of identifying functional elements in the human genome. Here we describe the utility of high-density oligonucleotide arrays as a rapid approach for comparing human sequences with the DNA of multiple species whose sequences are not presently available. High-density arrays representing approximately 22.5 Mb of nonrepetitive human chromosome 21 sequence were synthesized and then hybridized with mouse and dog DNA to identify sequences conserved between humans and mice (human-mouse elements) and between humans and dogs (human-dog elements). Our data show that sequence comparison of multiple species provides a powerful empiric method for identifying actively conserved elements in the human genome. A large fraction of these evolutionarily conserved elements are present in regions on chromosome 21 that do not encode known genes.

SK3 is an important component of K(+) channels mediating the afterhyperpolarization in cultured rat SCG neurones.

1. Our aim was to identify the small-conductance Ca(2+)-activated K(+) channel(s) (SK) underlying the apamin-sensitive afterhyperpolarization (AHP) in rat superior cervical ganglion (SCG) neurones. 2. Degenerate oligonucleotide primers designed to the putative calmodulin-binding domain conserved in all mammalian SK channel sequences were employed to detect SK DNA in a cDNA library from rat SCG. Only a single band, corresponding to a fragment of the rSK3 gene, was amplified. 3. Northern blot analysis employing a PCR-generated rSK3 fragment showed the presence of mRNA coding for SK3 in SCG as well in other rat peripheral tissues including adrenal gland and liver. 4. The same rSK3 fragment enabled the isolation of a full-length rSK3 cDNA from the library. Its sequence was closely similar to, but not identical with, that of the previously reported rSK3 gene. 5. Expression of the rSK3 gene in mammalian cell lines (CHO, HEK cells) caused the appearance of a K(+) conductance with SK channel properties. 6. The application of selective SK blocking agents (including apamin, scyllatoxin and newer non-peptidic compounds) showed these homomeric SK3 channels to have essentially the same pharmacological characteristics as the SCG afterhyperpolarization, but to differ from those of homomeric SK1 and SK2 channels. 7. Immunohistochemistry using a rSK3 antipeptide antibody revealed the presence of SK3 protein in the cell bodies and processes of cultured SCG neurones. 8. Taken together, these results identify SK3 as a major component of the SK channels responsible for the afterhyperpolarization of cultured rat SCG neurones.

FPP modulates mammalian sperm function via TCP-11 and the adenylyl cyclase/cAMP pathway.

Fertilization promoting peptide (FPP; pGlu-Glu-ProNH2), which is found in seminal plasma, promotes capacitation but inhibits spontaneous acrosome loss in mammalian spermatozoa in vitro. Adenosine, known to modulate the adenylyl cyclase (AC)/cAMP pathway, elicits these same responses whereas FPP + adenosine produces an enhanced response, leading to the hypothesis that FPP and adenosine modulate the same signal transduction pathway but act via different receptors. TCP-11, the product of a t-complex gene, is the putative receptor for FPP: Fab fragments of anti-TCP-11 antibodies have the same effect as FPP on mouse spermatozoa and Gln-FPP, a competitive inhibitor of FPP, also competitively inhibits responses to the Fab fragments. In the present study, specific binding of 3H-FPP to sperm membranes was significantly inhibited by 200 nM Gln-FPP and anti-TCP-11 Fab fragments (1/25 dilution), thus confirming that FPP, Gln-FPP, and Fab fragments compete for the same binding site. In addition, spermatozoa treated with A23187 to induce the acrosome reaction bound significantly less 3H-FPP than untreated cells, suggesting that a large proportion of the FPP binding sites are associated with the acrosomal cap region; TCP-11 is located in this region. In other experiments, 100 nM FPP significantly stimulated cAMP production in mouse sperm membranes, permeabilized cells and intact cells. Furthermore, Gln-FPP inhibited production of cAMP in response to FPP but not to adenosine (10 microM) or its analogue NECA (100 nM), supporting the involvement of two different receptors. Finally, anti-TCP-11 Fab fragments (1/25 dilution) significantly stimulated cAMP production, whereas low Fab (1/200; nonstimulatory when used alone) plus adenosine (10 microM) significantly enhanced the stimulation of capacitation by adenosine. These results support the hypotheses that TCP-11 is the receptor for FPP and that FPP<-->TCP-11 interactions modulate AC/cAMP.

TCP-11, the product of a mouse t-complex gene, plays a role in stimulation of capacitation and inhibition of the spontaneous acrosome reaction.

Tcp-11 is a candidate for a distorter gene within the t-complex on mouse chromosome 17; although t-complex genes appear to affect sperm function, relatively little is known about mechanisms whereby these genes might play a specific physiological role. We present evidence that the protein TCP-11 is found on the surface of mature epididymal spermatozoa. Although detected on both the acrosomal cap region of the head and the flagellum of acrosome-intact cells, it is absent from the heads of acrosome-reacted cells. When epididymal spermatozoa were incubated in the presence of anti-TCP-11 IgG Fab fragments for a total of 120 min and assessed using chlortetracycline fluorescence, we observed a stimulation of capacitation and an inhibition of spontaneous acrosome loss, suggestive of enhanced fertility compared with untreated suspensions. In vitro fertilization experiments confirmed that Fab-treated suspensions became fertile more quickly and then maintained high fertility. Because these responses were remarkably similar to those obtained using the TRH-related peptide FPP (fertilization promoting peptide; pGlu-Glu-ProNH2) and adenosine, we investigated responses to Fab fragments, FPP, and adenosine. Results indicated that the Fab fragments appear to work at the same extracellular site as FPP, one that is distinct from the adenosine site of action. Further evidence for this conclusion was obtained using pGlu-Gln-ProNH2, an FPP-related tripeptide known to competitively inhibit responses to FPP; as with FPP, pGlu-Glu-ProNH2 inhibited the stimulatory effect of Fab fragments in a concentration-dependent manner. From these results we suggest that TCP-11 may be the receptor for FPP and that the adenylate clyclase/cyclic AMP pathway may be the signal transduction pathway activated by interactions between extracellular effector molecules (e.g., Fab fragments or FPP acting as an agonist) and TCP-11. A mechanism such as this that promotes capacitation but inhibits spontaneous acrosome loss in vivo would play a very important role by helping to maximize the fertilizing potential of the few spermatozoa that reach the site of fertilization. The fact that there is a human homolog of Tcp-11 suggests that this gene could play an important role in regulation of human, as well as mouse, sperm function.

Effects of caerulein and CCK antagonists on tolerance induced to morphine antinociception in mice.

Different groups of mice received one daily dose (50 mg/kg) of morphine subcutaneously (SC) for 3, 4 or 5 days to develop tolerance to the opioid. The antinociceptive response of morphine (9 mg/kg) was tested in the hot-plate test 24 h after the last dose of the drug. Tolerance to morphine was obtained in all groups. The group of mice that received morphine for 4 days was employed for the rest of the experiments. Pretreatment of animals with a single dose of caerulein (0.025, 0.05, and 0.1 mg/kg, SC) 30 min prior to receiving morphine (50 mg/kg; during the development of tolerance to the opioid) on day 1, 2, 3, 4 or 5 of morphine administration potentiate antinociception induced by morphine (test dose of 9 mg/kg). The dose of 0.05 mg/kg of caerulein, used 30 min before morphine administration on day 3, was also used to evaluate the effects of antagonists on caerulein-induced decrease in tolerance. The selective cholecystokinin (CCK) receptor antagonists, MK-329 [1-methyl-3-(2 indoloyl)amino-5-phenyl-3H-1,4-benzodiazepin-2-one; 0.25 and 0.5 mg/kg] or L-365,260 [3R(+)-N-(2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H- 1,4-benzodiazepin-3-yl)-N-(3-methyl-phenyl)urea: 0.25 and 0.5 mg/kg] decreased potentiation of morphine response induced by caerulein. MK-329 or L-365,260, when were injected 35 min before morphine injection during the development of tolerance and on day 3, decreased the tolerance to morphine. A single administration of MK-329 or L-365,260 (in the absence of caerulein) 35 min and 48 h before the test dose of morphine (9 mg/kg) potentiated the antinociception of morphine in nontolerant animals. In conclusion, CCK mechanism(s) may interact with morphine tolerance.

Cost-effectiveness of routine blood type and screen testing before elective laparoscopy.

OBJECTIVE: To evaluate the usefulness and cost-effectiveness of the routine preoperative evaluation of blood type and screen testing before laparoscopy. METHODS: A retrospective review was conducted in patients transfused with blood during or after laparoscopy over a 3-year period at Hutzel Hospital, Detroit, Michigan; Grace Hospital, Southfield, Michigan; and Bixby Medical Center, Adrian, Michigan. RESULTS: Of 7529 women receiving laparoscopic procedures, 57 required blood transfusion at laparoscopy. Medical records of the 57 patients requiring blood transfusion were evaluated as to urgency and indication. All 57 subsequent blood transfusions were found to be the result of previously identifiable problems, including ectopic pregnancy and preoperative anemia. No patient required transfusion for a vascular injury. CONCLUSION: In the absence of preoperative indications, routine preoperative type and screen testing for elective and emergency laparoscopic procedures does not enhance patient care and should be eliminated.

Beta-N-acetylhexosaminidases A and S have similar sub-cellular distributions in HL-60 cells.

In HL-60 cells the most abundant isoenzymes of beta-N-acetyl-hexosaminidase are A (alpha beta) and S (alpha alpha). Sub-cellular fractionation of HL-60 cells by differential centrifugation showed that both A and S forms were present in the lysosomal and post-lysosomal (soluble) fractions in approximately equal abundance. Ion-exchange chromatography showed that a fraction enriched with plasma membranes had the A form, and a form of beta-N-acetylhexosaminidase less acidic than A, but there was no S. Analysis of the alpha-subunits of beta-N-acetylhexosaminidases A and S using Western blotting and immuno-detection with antisera raised to synthetic peptides showed that mature alpha-subunits were present in both A and S isolated from the lysosomal fraction. This observation establishes that the alpha alpha-dimer of beta-N-acetyl-hexosaminidase (S) can be transported to lysosomes in HL-60 cells whereas there is good evidence that this does not take place in fibroblasts. HL-60 cells were not stimulated to secrete lysosomal enzymes by incubating them with NH4Cl and, unlike fibroblasts, are unlikely to use mannose-6-phosphate mediated transport of beta-N-acetylhexosaminidases to lysosomes. Comparison of the sequence of the beta-N-acetylhexosaminidase alpha-subunit with a 43 amino acid sequence of cathepsin D, though to function in the mannose-6-phosphate independent targeting of this enzyme to lysosomes, showed alignment in a region towards the C-terminus in which 21% of the residues were identical with the interposition of a one amino acid gap.