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Biomedical subjects

A Mahmoud

Publications and source records attributed to A Mahmoud.

At least 19 recordsLinked to original sources
PubMed2006

Evidence for multiplication of the leafhopper-borne maize yellow stripe virus in its vector using ELISA and dot-blot hybridization.

Maize yellow stripe virus (MYSV) has several features in common with tenuiviruses, but is transmitted by a leafhopper, Cicadulina chinai (Cicadellidae, Hemiptera), rather than planthoppers (Delphacidae, Hemiptera). Herein, MYSV was shown to be propagatively transmitted like tenuiviruses. MYSV RNA was not detected in leafhoppers by dot blot hybridization one day following a 2-day acquisition access period (AAP), but was detected in single or groups of leafhoppers 5-20 days post-acquisition. Likewise, capsid protein of MYSV was not detected by ELISA in single leafhoppers until the third day after the beginning of a 1- or 3-day AAP, but subsequently, mean absorbance values (405 nm) increased gradually, reaching their highest levels 8-14 days post-acquisition. The percentage of ELISA-positive leafhoppers also increased during the same period. Unlike most tenuiviruses, transovarial transmission of MYSV was not detected in 600 C. chinai nymphs that hatched from eggs laid by females that had acquired MYSV from diseased plants. The implications of our findings for MYSV classification are discussed.

Animals↗
PubMed2005

Reconstructed epidermis versus human and animal skin in skin absorption studies.

European chemical policy in general and the REACH initiative in particular will increase the number of chemical substances submitted to toxicological evaluation by several orders of magnitude compared to the current status. To limit animal exposure the resulting enormous increase in testing, however, asks for validated in vitro test systems. While the OECD favours in vitro testing for cutaneous absorption using viable human and animal skin (Guideline 428) the availability of viable human skin is already limited today. We present a comparison of various in vitro techniques suitable for routine skin absorption studies including commercially available reconstructed human epidermis which may be a reliable alternative to excised human and animal skin. In order to develop a protocol for the subsequent transfer to partner laboratories the experimental set-up was analysed stepwise using the OECD reference compounds caffeine and testosterone. Franz cell type, the donor and receptor media for hydrophilic/lipophilic substances, albumin and tensid addition, and storage conditions of the excised skins were systematically varied. A protocol has been developed which now allows to proceed to the pre-validation process.

Administration, Topical↗
PubMed2005

Is inhibin B involved in the toxic effect of lead on male reproduction?

Human studies indicate exposure to lead is associated with decreased sperm quality with modest, if any, effects on conventional reproductive endocrine profile. Inhibin B is a marker of Sertoli cell function and spermatogenesis. The present study evaluates possible effects of lead exposure on serum levels of inhibin B in a group of lead workers as compared with a non-exposed group of hospital personnel. The study population included 68 healthy Belgian workers from a lead smelter (Hoboken, Belgium) and for comparison a control group of 91 hospital personnel (University Hospital Ghent, Belgium). Semen analysis and measurement of current blood lead levels and serum levels of inhibin B, follicle stimulating hormone (FSH) and estradiol (E2). Lead workers had significantly lower sperm concentration (35 vs. 51 million/mL) and higher serum inhibin B (259 vs. 177 pg/mL) as well as lead blood levels 30.9 vs. 3.4 mug/dL) compared with the hospital personnel (all p < 0.05). Serum FSH and E2 levels were similar in both groups. Overall, inhibin B levels correlated significantly positively with blood lead levels and sperm concentration while it was negatively correlated with serum FSH. In multiple regression analysis of data from all participants, blood lead and serum FSH (p < 0.0001 for both) followed by sperm count (p = 0.007) were selected as the only independent variables for inhibin B with an R-adjusted coefficient of determination of 0.3714. The results of the present study suggest that the exposure of the cells of Sertoli to excessive amounts of lead results in inappropriate inhibin B overproduction that may be involved in the impairment of spermatogenesis.

Adult↗
PubMed2005

Combined conventional/antioxidant "Astaxanthin" treatment for male infertility: a double blind, randomized trial.

AIM: To evaluate the treatment of male infertility with a strong natural antioxidant, in addition to conventional treatment. METHODS: Using a double blind, randomized trial design, 30 men with infertility of > or =2 months and female partners with no demonstrable cause of infertility received conventional treatment according to the guidelines of the World Health Organization (WHO), and either a strong antioxidant Astaxanthin 16 mg/day (AstaCarox, AstaReal AB, Gustavsberg, Sweden) or placebo for 3 months. The effects of treatment on semen parameters, reactive oxygen species (ROS), zona-free hamster oocyte test, serum hormones including testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and Inhibin B, and spontaneous or intrauterine insemination (IUI)-induced pregnancies were evaluated. RESULTS: ROS and Inhibin B decreased significantly and sperm linear velocity increased in the Astaxanthin group (n = 11), but not in the placebo group (n = 19). The results of the zona-free hamster oocyte test tended to improve in the Astaxanthin group in contrast with the placebo group, though not reaching statistical significance. The total and per cycle pregnancy rates among the placebo cases (10.5 % and 3.6 %) were lower compared with 54.5 % and 23.1 % respectively in the Astaxanthin group (P = 0.028; P = 0.036). CONCLUSION: Although the present study suggests a positive effect of Astaxanthin on sperm parameters and fertility, the results need to be confirmed in a larger trial before recommending Astaxanthin for the complementary treatment of infertile men.

Adult↗
PubMed2004

Anti-genotoxic and free-radical scavenging activities of extracts from (Tunisian) Myrtus communis.

The effect of extracts from leaves of Myrtus communis on the SOS reponse induced by Aflatoxin B1 (AFB1) and Nifuroxazide was investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37. Aqueous extract, the total flavonoids oligomer fraction (TOF), hexane, chloroform, ethyl acetate and methanol extracts and essential oil obtained from M. communis significantly decreased the SOS response induced by AFB1 (10 microg/assay) and Nifuroxazide (20 microg/assay). Ethyl acetate and methanol extracts showed the strongest inhibition of the induction of the SOS response by the indirectly genotoxic AFB1. The methanol and aqueous extracts exhibited the highest level of protection towards the SOS-induced response by the directly genotoxic Nifuroxazide. In addition to anti-genotoxic activity, the aqueous extract, the TOF, and the ethyl acetate and methanol extracts showed an important free-radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. These results suggest the future utilization of these extracts as additives in chemoprevention studies.

Aflatoxin B1↗
PubMed2004

Preventing diseases of the prostate in the elderly using hormones and nutriceuticals.

The prostate has only one function, namely to secrete fluid containing substances that are needed for reproduction. This requires an extremely high concentration of androgens in the tissues. Benign prostatic hypertrophy (BPH) seems to be related to the long-term exposure of the prostate to the strong androgen 5alpha-dihydrotestosterone (DHT) and, possibly, to estrogens. The relation between prostate cancer and androgens is suggested to be U-shaped, with both extremes of androgen concentrations being associated with increased risk of invasive cancer. In the treatment of patients with BPH, the lipidic liposterolic extracts of Serenoa repens were as effective as the pharmaceutical inhibitors of the 5alpha-reductase enzyme or alpha1-adrenergic blockers in relieving urinary symptoms. In addition to moderately inhibiting the 5alpha-reductase activity, Serenoa seems to exert anti-inflammatory and complementary cellular actions with beneficial effects on the prostate. Unlike the pharmaceutical 5alpha-reductase inhibitors, finasteride and dutasteride, Serenoa does not suppress serum PSA, facilitating the follow-up and the early detection of prostate cancer. We suggest a strategy to prevent prostate cancer that aims at providing men with partial androgen deficiency correct testosterone substitution with a sustained release buccal bio-adhesive tablet. In addition, food supplementation with extracts of Serenoa repens and a combination of the antioxidants selenium, (cis)-lycopene and natural vitamin E, together with fish oil rich in long-chain polyunsaturated essential fatty acids of the omega-3 group seems warranted. Clearly, a holistic approach including careful clinical and biological monitoring of the aging man and his prostate remains mandatory.

Aged↗
PubMed2003

Chronic prostatitis and male accessory gland infection--is there an impact on male infertility (diagnosis and therapy)?

The aim of this article was to discuss by means of a review of the literature and own study material the multifactorial aetiology of male infertility, extrapolate this hypothesis to male accessory gland infection (MAGI) and relate it to chronic prostatitis and its treatment. Infertility is a multifactorial disease and diagnosis and therapy must be oriented as such. Although the relationship between prostatitis and infertility remains unclear, bacteria, viruses, leucocytes, reactive oxygen species, cytokines, obstruction and immunological abnormalities must be seen as cofactors in the development of infertility in patients with MAGI and prostatitis. Infection, trauma, allergy, neurogenic damage, chemical or mechanical factors can lead to a long-lasting inflammation of the prostate or pelvic organs even after eradication of the aetiological agent, and is potentially related to infertility through cytokines. In relation to treatment of infertility, antibiotics play a role in bacterial prostatitis whereas in abacterial prostatitis other treatments like antioxidants, sacral nerve stimulation and anti-inflammatory treatment are worth to be studied in the future.

Chronic Disease↗
PubMed2001

Fading renal hyperfiltration in children following liver transplantation.

In a prospective longitudinal study, we investigated the renal function (RF) of 23 children before and after orthotopic liver transplantation (OLT). The aim was to assess both the outcome of pretransplant hyperfiltration and the clinical nephrotoxic effects of cyclosporin A (CsA); children with decreased RF prior to OLT were therefore excluded. The RF study of the 13 remaining patients included glomerular filtration rate (GFR) and effective renal plasma flow (RPF) measured by inulin (Cin: mL/min/1.73 m2) and para-amino hippurate (Cpah: mL/min/1.73 m2) clearances, respectively. Hyperfiltration prior to OLT was observed in six children, i.e. Cin>170 [range 172-230] and Cpah>800 [808-1,133]. A significant decrease in RF was noted as soon as 6 months after OLT: Cin (mean+/-SD)=107+/-23 vs. 158+/-46 (p<0.003); Cpah=583+/-119 vs. 791+/-243 (p<0.004). This was due to loss of hyperfiltration in the six children, as there was no significant difference in RF before and 6 months after OLT in the other seven children. With a 36-month follow-up, there was no correlation between CsA trough blood level and RF. In conclusion, following OLT, RF underwent early changes owing to loss of prior hyperfiltration in children without impaired RF before OLT. In addition, no evidence of CsA nephrotoxicity was found and RF remained stable during follow-up.

Acute Kidney Injury↗
PubMed1999

[A strategy for the prevention of male infertility].

Since 1990 there has been a simultaneous reduction of natality in Flanders (by approximately 12%) with increased demand for assisted reproduction, while sperm quality, mostly motility and morphology, have clearly deteriorated over recent decades. This evolution has been ascribed to the deleterious effects of hormone disrupting substances in the environment, synergistically enhancing unfavorable influences from life style and possible genito urinary diseases that can impair the function of the testes and accessory sex glands. It is probable that this synergistic effect is exerted through the intermediate of free oxygen radicals (also called reactive oxygen species) that damage both the sperm membrane and sperm DNA, which could allow certain minimal inborn genetic defects (such as point lesions) to come to expression. Both pseudo- or xeno-estrogens (such as certain organo chlorides, alkyl phenols, phthalates, etc.) and anti-androgens are held responsible for prenatal testicular damage and increased prevalence of testicular carcinoma and oligozoospermia, for anatomical malformations, as well as postnatal depression of testicular function and spermatogenesis. However, methods presently available to detect hormone disrupters are tedious and not fully adequate. A first strategic goal is to develop a simple method for the detection of these substances so that environmental pollution can be mapped. Fazing out the production and application of hormone disrupters, and removing them from the environment are the second strategic step. Also, a health food is being developed that will inhibit the absorption of these chemicals from the intestinal tract. In addition it is projected to detect and treat common genital diseases that can cause infertility, such as varicocele and infection of the urinary tract and accessory sex glands. The first could be organized to take place during medical examinations at school, whereas the second requires correct medical treatment of any cysto urethritis in adolescents. Non surgical treatment of varicocele by means of transcatheter embolization offers a cost effective approach, with minimal risk and complications, and high level of efficacy. Improving food quality and educational efforts aimed at a healthier life style should score high priority. The suggested strategy uses several entries in order to address the multifactorial mechanisms involved in the pathogenesis of male infertility. Preliminary epidemiological and biological data suggest that the proposed strategy can, indeed, be successful within a relatively short lapse of time.

Belgium↗
PubMed1998

Laparoscopic control of bleeding liver laceration.

The role of laparoscopy in the management of solid-organ intraabdominal injuries has still not been fully elucidated. The following is a case report of successful laparoscopic control of a bleeding liver laceration, grade III (following CT-guided liver biopsy), after unsuccessful attempts at angiographic embolization.

Biopsy, Needle↗
PubMed1998

Mechanisms of sperm deficiency in male accessory gland infection.

The presence of 2 million or more peroxidase-positive white blood cells per ml of semen, or the diagnosis of male accessory gland infection, is associated with important biochemical and biological changes in semen plasma and in the spermatozoa, reducing their fertilizing potential in vitro and in vivo (e.g., during intra-uterine insemination). In addition to the effects of reactive oxygen species, and its influence on the essential fatty acid composition of the sperm membrane, potentially unfavourable effects can occur through the intermediate of increased concentrations of certain cytokines, and decreased activity of enzymes such as alpha-glucosidase. In contrast, lower numbers of white blood cells may exert beneficial effects on spermatozoa thanks to the increased production of hepatocyte growth factor/scatter factor (a tissue repairing substance), and the stimulation of immuno-competent cells by particular cytokines (e.g., Interleukin-6).

Cytokines↗
PubMed1997

Advantage of surgery and adjuvant chemotherapy in the treatment of primary gastrointestinal lymphoma.

BACKGROUND: Surgery has been the mainstay of treatment for gastrointestinal (GI) lymphoma. The role of adjuvant chemotherapy to surgery has not been clearly elucidated. METHODS: The review covered 100 patients who were diagnosed with primary GI lymphoma and treated from 1980 to 1993 at Providence Hospital (Southfield, MI), and Hartford and St. Francis Hospitals (Hartford, CT) with a median follow-up of 5 years. Forty-two patients were treated with surgery alone; 31 patients with surgery and adjuvant chemotherapy; 23 patients with primary chemotherapy, and 4 patients received no treatment. RESULTS: The 5-year actuarial survival based on the above treatments calculated by life-table analysis were 57%, 76%, 58%, and 0%, respectively. This series showed that surgery with adjuvant chemotherapy significantly improved the 5-year actuarial survival of patients with primary GI Lymphoma and that primary chemotherapy showed comparable survival to surgery alone. There was no difference in prognosis when comparing patients with different stage, grade, or location of disease in the GI tract. CONCLUSIONS: We recommend surgery when feasible with adjuvant chemotherapy as the mainstay of treatment for primary GI lymphoma. However, if a patient presents with comorbid factors, primary chemotherapy offers an effective alternative.

Adolescent↗
PubMed1997

Outcome of preemptive renal transplantation and pretransplantation dialysis in children.

The present study compares the outcome of 40 children (39%) transplanted without prior dialysis, i.e., preemptive transplantation (PET), with 63 children (61%) transplanted after a variable duration of dialysis, i.e., pretransplantation dialysis (PTD). The two groups were matched for recipient and donor age and for immunological risk factors. There was no statistical difference in the time to first acute rejection episode nor in the number of acute rejection episodes during the 1st year after renal transplantation. In the PET group, 78% of the recipients received blood transfusion versus 92.5% in the PTD group (P < 0.05), and the average number of blood units per patient was 3.2 and 7.8, respectively (P < 0.05). Arterial hypertension was found in 55% of the patients in the PET group versus 73% in the PTD group (P < 0.05). The number of functioning grafts at the end of the study period was 87.5% in the PET group and 73% in the PTD group (NS). The major cause of graft failure was vascular thrombosis in the PET group (3/5) and chronic allograft rejection in the PTD group (10/17). In the PET group, the actuarial graft survival rate was 100%, 84%, 81%, and 76% at 1, 3, 5, and 7 years, which was not statistically different from the PTD group at 1, 3, and 5 years (98%, 91%, and 73%, respectively) but there was a significantly lower graft survival (59%) after 7 years in the PTD (P < 0.05). The 7-year actuarial patient survival rate was 97% in the PET group and 90% in the PTD group (NS). In the PTD group, children on dialysis for less than 1 year (group 1, n = 25) were compared with those on dialysis for more than 1 year (group 2, n = 38). Arterial hypertension was noted in 40% of patients from group 1 and 65% from group 2 (P < 0.05); there was no significant difference in graft loss rate. In conclusion, these results confirm PET as the preferred approach rather than PTD in children who need renal replacement therapy.

Child↗