Biomedical subjects

A Ahmadi

Publications and source records attributed to A Ahmadi.

At least 37 records · Page 2Linked to original sources

PubMed1999

Glutathione S-transferase T1 and M1 genotypes in normal mucosa, transitional mucosa and colorectal adenocarcinoma.

Gene codings for glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) are polymorphic in humans with null genotypes present in approximately 20 and 50%, respectively. A significant excess of homozygous null GSTT1 and GSTM1 genotypes has been demonstrated among individuals with certain types of cancers. This finding suggests that GSTT1 and GSTM1 may play a role in tumour susceptibility. However, reports concerning colorectal cancer susceptibility are controversial. In the present study, we used a multiplex polymerase chain reaction (PCR) approach to identify and analyze simultaneously the genotypes of both the genes in 99 patients with colorectal cancer and 109 healthy controls. Compared with the control group, a significant excess of homozygous null genotypes for GSTT1 was found in normal mucosa among the cancer patients, but not for GSTM1. Both genes were more frequently deleted in tumours than in corresponding normal mucosa. Furthermore, GSTT1 null genotype in tumour tissue, was significantly related to old age and to poor differentiation of tumours. GSTM1 null genotype in tumour was more frequent in the rectal tumours compared with tumours of left colon and right colon. Our results suggest that individuals with GSTT1 null genotype may be genetically predisposed for an increased risk of developing colorectal cancer. Allele loss in tumour tissue, which reflects genetic instability, may be considered as a marker for evaluating clinico-pathological characteristics of the cancer patients.

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PubMed1999

Destruction of protamine in human sperm inhibits sperm binding and penetration in the zona-free hamster penetration test but increases sperm head decondensation and male pronuclear formation in the hamster-ICSI assay.

PURPOSE: Our purpose was to investigate the fertilizing ability of human protamine-damaged sperm in a heterologous system using hamster oocytes. METHODS: The protamine of the sperm were damaged by exposure to dithiothreitol, a disulfide-reducing agent. Their ability to penetrate and form male pronuclei were investigated using the zona-free hamster penetration test and the hamster-intracytoplasmic sperm injection assay, respectively. RESULTS: The zona-free hamster penetration test revealed that protamine-damaged sperm are unable to bind and penetrate the hamster oocyte. On the other hand, hamster-intracytoplasmic sperm injection assay results showed that 56.9% and 39.2% of the injected oocytes developed male pronuclei in protamine-damaged and live-intact sperm groups, respectively, with a significant difference in these rates (P < 0.01). CONCLUSIONS: This study shows that protamine-damaged sperm are able to undergo sperm head decondensation and male pronuclear formation only when injected into the ooplasm, although they cannot bind and penetrate through the zona and enter the ooplasm.

Acridine Orange↗

PubMed1999

Impact of different therapeutic alternatives in treatment of severe limb ischemia: experiences on 190 consecutive patients at a department of medical angiology.

BACKGROUND: Different therapies in consecutive patients (1987-1992) with chronic critical limb ischemia at a department of medical angiology, their short- and long-term outcome were investigated. PATIENTS AND METHODS: 190 patients (112 males, 78 females; age: 67 +/- 12 years); 78 in grade II, 112 in grade III according to Rutherford's classification. Therapeutic regimen: 1. vascular recanalisation by percutaneous transluminal angioplasty [PTA], local or systemic lysis; 2. surgical vascular reconstruction in case of impossibility or failure of catheter procedures; 3. prostanoids and/or antibiotics; 4. local wound treatment including amputations. RESULTS: Vascular recanalisation was attempted in 156/190 (82.1%): PTA in 116/190, surgical vascular reconstruction in 50/190, local in 24/190 and systemic lysis in 8/190 patients. Prostanoids were applied in 89/190 and antibiotics in 73/190 patients. At the time of dismissal 164/190 (86.3%) patients were clinically improved; 11/190 (5.8%) unchanged, 13/190 (6.8%) had undergone major amputations and 2/190 (1.1%) had died. After 2.6 +/- 2.2 years 77 of the 141 patients, who were still alive, were reexamined. Among these 77 patients 84.4% were in grade 0 or 1, 15.6% in chronic critical limb ischemia. Furthermore 13.0% had been amputated since dismissal. Forty-nine of 190 (25.8%) patients had died 3.2 +/- 1.9 years after dismissal from hospital. CONCLUSION: Catheter techniques, mostly PTA, is possible in the majority of patients with chronic critical limb ischemia. Cooperation with vascular surgeons in case of technical impossibility or failure of catheter recanalisation is mandatory. Such a regimen yields satisfactory short- and long-term results and a low rate of complications.

Aged↗

PubMed1999

Developmental capacity of damaged spermatozoa.

We report the first detailed and systematic study in a mammalian system to unravel the mystery of the beginnings of life. The fertilizing ability of damaged spermatozoa at various levels of disintegration (cellular and molecular) has been investigated in homologous (mouse) and heterologous (human spermatozoon, hamster oocyte) models. Live pups were produced after destruction of spermatozoa at various cellular and molecular levels followed by injection into oocytes. We demonstrate that with damaged spermatozoa, the key point in the fertilization process is the activation of the oocyte by injection of cytosolic sperm factor. A similar fertilization rate as that using live intact spermatozoa can be achieved following activation. However, the integrity of the genetic material influenced in-vitro development of the embryos and live fetuses. This study contributes to a better understanding of the fertilizing ability of damaged spermatozoa. These findings can be applied clinically to patients with necrozoospermia or very severe oligozoospermia and in wildlife research where damaged spermatozoa from rare species can be used to regenerate young, and hence propagate the species. Also implied is the possible contribution of sperm DNA strand breakage to early pregnancy loss.

Animals↗

PubMed1998

Two novel mutations of the vasopressin gene associated with familial diabetes insipidus and identification of an asymptomatic carrier infant.

Familial diabetes insipidus (FDI) is a syndrome of central vasopressin deficiency that is inherited in an autosomal dominant manner and that typically becomes clinically apparent in the first decade of life. Two novel mutations of the vasopressin gene have been identified in two previously unstudied kindreds with FDI. In each kindred, the inheritance of the FDI phenotype was consistent with an autosomal dominant mode of inheritance. In each proband, the diagnosis of central diabetes insipidus had been confirmed previously with a water deprivation protocol. After extraction of genomic DNA from each individual, the three exons of the vasopressin gene were separately amplified by PCR and directly sequenced using an automated dye termination method. In the proband and two other carriers of one kindred, a heterozygous C to T mutation was identified at nucleotide 1857. This is predicted to produce a serine to phenylalanine substitution at residue 56 of the vasopressin-related neurophysin peptide encoded by the mutated allele. The mutation also abolished an MspI site in the vasopressin sequence, and analysis of genomic DNA from eight members of the kindred (five with FDI) confirmed segregation of the mutation with the FDI phenotype. Another member of the kindred, a 13-month-old infant, also has the heterozygous C to T mutation, but a formal water balance study showed no evidence of diabetes insipidus. In the proband of the other kindred, a heterozygous G to A mutation was identified at nucleotide 1873. This mutation would be predicted to cause a cysteine to tyrosine substitution at residue 61 of the neurophysin encoded by the mutated allele. This heterozygous mutation was confirmed by the presence of an RsaI restriction site in one vasopressin allele in two members of the kindred. Therefore, two novel heterozygous mutations of the vasopressin gene have been identified in FDI kindreds. In one kindred, an asymptomatic carrier infant was identified and will require continued observation to determine whether she will develop clinical diabetes insipidus. The presence of these two novel mutations in a region of the vasopressin gene where other FDI mutations have been reported suggests that the part of the neurophysin peptide encoded by these sequences may be critically important in the appropriate expression of vasopressin.

Diabetes Insipidus↗

PubMed1998

Color duplex sonography guided stent placement in a stenosis of the superficial femoral artery. A case report.

We report the first case of a successful stent placement under color coded ultrasound guidance alone in the superficial femoral artery of a 73-year-old woman suffering from intermittent calf claudication following restenosis after an uncomplicated angioplasty five months previously. Because of a hemodynamically residual stenosis after three attempts at dilatation, a percutaneous transluminal angioplasty and stent insertion were performed under the sole guidance of color coded ultrasound. The intervention was performed without complication and at the six-month follow-up examination, the patient was symptom-free and the stent was morphologically intact and hemodynamically functional. This case shows that successful stent placement under ultrasonic guidance alone, without fluoroscopic control is possible, provided that there is adequate sonographic visualization.

Aged↗

PubMed1997

Effects of antimicrobial treatment at the end of lactation on milk yield, somatic cell count, and incidence of clinical mastitis during the subsequent lactation in a dairy herd with a low prevalence of contagious mastitis.

OBJECTIVE: To determine whether treating cows with antimicrobials at the end of lactation would lower the incidence of clinical mastitis, improve milk production, and decrease somatic cell count (SCC) in the subsequent lactation. DESIGN: Randomized blind field trial. ANIMALS: 233 Holstein cows from a single herd. All cows were in lactation 2 or greater. PROCEDURE: Cows were randomly assigned to treatment groups. Treated cows were given procaine penicillin G and novobiocin by intramammary infusion. Control cows were not treated. Farm personnel recorded cases of clinical mastitis. Milk yield and SCC were recorded during the subsequent lactation. RESULTS: Treatment did not significantly reduce the incidence of clinical mastitis when data for all cows were grouped or when data were stratified by lactation groups (lactation 2 vs lactation > or = 3) or by last SCC (< or = 500,000 cells/ml vs > 500,000 cells/ml). Somatic cell counts (first, mean of first 5, maximum of first 5) for treated and control cows were similar, and proportions of treated and control cows with SCC > 500,000 cells/ml at least once were not significantly different. Treated cows produced 179 kg (394 lb) more milk during the first 17 weeks of lactation than did control cows. CLINICAL IMPLICATIONS: Treating cows with antimicrobials at the end of lactation increased 17-week milk production during the subsequent lactation and, at current milk prices, was financially preferable to not treating them.

Analysis of Variance↗

PubMed1997

The single sperm curling test, a modified hypo-osmotic swelling test, as a potential technique for the selection of viable sperm for intracytoplasmic sperm injection.

OBJECTIVE: To develop a technique for the selection of viable sperm for intracytoplasmic sperm injection (ICSI), based on the phenomenon of sperm tail curling in a hypo-osmotic environment, through modification of the hypo-osmotic swelling test. DESIGN: Individual sperm were exposed to single sperm curling (SSC) medium and then injected into hamster oocytes to study the effect of SSC medium on fertilization. SETTING: All materials were collected from the National University Hospital in Singapore. PATIENT(S): Semen of proven donors and hamster oocytes with intact zonae were used. INTERVENTION(S): ICSI and the SSC test. MAIN OUTCOME MEASURE(S): Sperm head decondensation and male pronucleus formation. RESULT(S): Sperm head decondensation and male pronucleus formation were present in 59.4% and 42.4%, respectively, of the oocytes injected with sperm that had been exposed to SSC medium. These rates were 70% and 48.8%, respectively, when the sperm were washed thoroughly after exposure to SSC medium. In the control group (sperm that were not exposed to SSC medium), these rates were 68.8% and 46.2%, respectively. CONCLUSION(S): The SSC test is useful for the selection of viable sperm for ICSI. It allows the behavioral study of a single sperm in hypo-osmotic conditions. Thorough washing of the exposed sperm is important. This procedure would be of benefit especially in testicular biopsies or very severe cases of low sperm count in which only a few sperm are found among many other cells and artifact.

Animals↗

PubMed1997

Endovascular AAA treatment: expensive prestige or economic alternative?

OBJECTIVES: To compare the costs of endovascular aneurysm treatment versus open surgery during the perioperative period. METHODS: Retrospective analysis of a consecutive series of 44 patients undergoing infrarenal abdominal aneurysm repair from February 1995 to March 1996 at a university teaching hospital. RESULTS: No endovascular procedure was converted to open repair. Operative time was shorter for endovascular treatment (207.6 min vs. 229.1 min, n.s.), as well as postoperative intensive care unit stay (ICU, 22.7 h vs. 55.0 h, p = 0.017) and the postoperative recovery period (5.6 days vs. 13.3 days, p < 0.001). Open surgery generated significantly more costs (25,374.07 ECU vs. 22,268.78 ECU, p < 0.001), despite evaluation and a more expensive endovascular procedure (10,699.48 ECU vs. 4032.01 ECU, p < 0.001). During the study, costs for open surgery exceeded the cost for endovascular treatment by 13.95%. CONCLUSIONS: Endovascular aneurysm treatment is cost effective and less expensive than open surgery. The main reason for cost saving is faster patient recovery after surgery, associated with a shorter LOS in the patients treated with endovascular procedure.

Aged↗

PubMed1997

Sperm head decondensation, pronuclear formation, cleavage and embryonic development following intracytoplasmic injection of mitochondria-damaged sperm in mammals.

The objective of this study was to investigate the influence of sperm mitochondrial destruction on sperm head decondensation, male pronuclear formation, cleavage and embryonic development. In the study two models were used: heterologous (hamster ICSI assay: human sperm injected into a hamster oocyte) for evaluation of sperm head decondensation and pronuclear formation, and homologous (mouse model) for the study of fertilisation and development. Destruction of mitochondria of the sperm was achieved by exposure to cyanide, a respiratory poison. Rhodamine 123 was used to evaluate the functional integrity of mitochondria. Sperm head decondensation was found to be not statistically significantly affected by mitochondrial damage (p = 0.8), with 62.8% and 67.9% condensation in the experimental and control groups respectively. Male pronucleus formation was seen in 40.2% and 44.4% of the injected oocytes in the experimental and control groups respectively. In the mouse experiments 45.5% and 49.7% of the injected oocytes were fertilised in the mitochondria-damaged and live-intact sperm groups respectively (p = 0.53). Development to blastocyst was achieved in 53.5% and 59.4% of the experimental and control groups respectively; the difference was not significant (p = 0.71). Inner cell mass (ICM) cell number were 15.7 +/- 4.12 and 43.1 +/- 11.3 respectively in the mitochondria-damaged group; the equivalent numbers were 14.12 +/- 4.02 and 39.3 +/- 12.6 in the control group. However, the differences in ICM and total cell counts between these two groups were not significant. Of the blastocysts transferred to pseudopregnant mice, 51.3% (20/36) implanted and 33.4% (12/36) developed to live fetuses in the mitochondria-damaged group. These rates were 60.5% (23/38) and 39.5% (15/38) in the control group. In conclusion, this study shows that functional integrity of the sperm mitochondria is not necessary in the process of fertilisation and development when the sperm is deposited into the ooplasm. Fertilisation and development can be achieved by injection of sperm at the very early stage of necrosis in which only the mitochondria have been destroyed and the rest of the cell including the plasma membrane is still intact.

Animals↗

PubMed1997

Fertilization and development of mouse oocytes injected with membrane-damaged spermatozoa.

The objective of this study was to investigate the influence of sperm plasma membrane on fertilization and development in a mouse model. The sperm plasma membrane was destroyed by exposure to Triton X-100 prior to intracytoplasmic sperm injection (ICSI). A single sperm curling (SSC) test was used to evaluate cell viability. The fertilization rates of oocytes obtained following ICSI of membrane-damaged sperm was not significantly higher than that of the control group (62.4 versus 59.6%). Rates of development to blastocyst were also not significantly different (51.7 and 50%). Inner cell mass (ICM) and total embryo cell numbers in the two groups were not statistically different (16 +/- 3.7 versus 14.73 +/- 3.35 and 45.8 +/- 12.5 versus 39.5 +/- 12 respectively). There were no differences in the implantation and live fetus rates between the two groups after transfer to pseudopregnant mice (61.5 and 35.9% respectively for the membrane-damaged group and 53.5 and 31.4% for the intact group). In conclusion, the present study clearly shows that destruction of the sperm plasma membrane does not affect fertilization and further development following injection of membrane-damaged spermatozoa into mouse oocytes. Fertilization and development can be achieved by dead spermatozoa at an early stage of necrosis when only the plasma membrane has been damaged.

Animals↗

PubMed1996

Sensitivity and specificity analysis for somatic cell count (SCC) used to predict bacteriologically positive subclinical mastitis at calving in a dairy herd with low SCC.

OBJECTIVE: Validate, by sensitivity and specificity analyses, use of somatic cell count (SCC) to predict bacteriologically positive subclinical mastitis in a California dairy herd with low SCC. DESIGN: Study of monthly dairy herd improvement SCC obtained from the immediate preceding lactation and individual cow composite milk sample microbiologic isolates collected at calving. ANIMALS: 515 California dairy cows with SCC and culture data. PROCEDURE: Somatic cell count sensitivity and specificity analyses with combinations of SCC parameter and at various thresholds were done, using the bacterial isolates as the standard. RESULTS: Combination of SCC threshold and SCC parameters could not be developed that had sufficient sensitivity and specificity to be a useful predictor of cows that would calve with subclinical mastitis. CLINICAL IMPLICATIONS: Under the conditions at this particular dairy, SCC could not be used as a basis of prediction of cows that would calve with bacteriologically positive subclinical mastitis or require selective nonlactating-cow antibiotic treatment.

Animals↗

PubMed1996

Intracytoplasmic injection of human sperm into the hamster oocyte (hamster ICSI assay) as a test for fertilizing capacity of the severe male-factor sperm.

OBJECTIVE: Our objective was to investigate the fertilizing ability of human sperm from severe male-factor patients, by microinjection of single sperm into the hamster oocyte. DESIGN: Semen samples of severe male factor either with a 0% penetration rate in the zona-free hamster test or with a very low number of motile sperm for which performing the standard penetration test was impossible were used. For the control study, oligozoospermic semen samples with at least 10% penetration rate in zona free hamster test were used. SETTING: All materials were collected from the National University Hospital, Singapore. METHODS: There were 10 patients in both the experimental and the control groups. Intracytoplasmic sperm injection (ICSI) was carried out. The main outcome measures were sperm head decondensation and pronuclear formation. RESULTS: Twenty-one percent of the injected sperm could decondense and undergo male pronuclear formation. This rate was not significantly different from that in the control study group (28%; P = 0.13). A small proportion of the oocytes was damaged during the procedure (9.2 and 8.75% in experimental and control groups, respectively). CONCLUSIONS: Hamster-ICSI assay may be of benefit in predicting the sperm's ability for further development before allowing the patient to undergo the clinical program.

Animals↗

PubMed1996

Demonstration of cystic adventitial disease by intravascular ultrasound imaging.

In a 34-year-old woman with intermittent calf claudication, cystic adventitial disease of the popliteal artery was demonstrated by intravascular ultrasound imaging. Multiple intramural cystic masses were seen to be compressing the arterial lumen. The diagnoses of cystic adventitial disease was confirmed by surgery. Intravascular ultrasound imaging reliably identifies cystic adventitial disease; its application can be recommended as an alternative to established diagnostic procedures (computed tomography, magnetic resonance imaging) in patients undergoing angiography.

Adult↗

PubMed1996

Femoropopliteal artery: initial and 6-month results of color duplex US-guided percutaneous transluminal angioplasty.

PURPOSE: To evaluate color duplex ultrasonographic (US) guidance of percutaneous transluminal angioplasty (PTA) of femoropopliteal artery stenoses and occlusions. MATERIALS AND METHODS: Twenty-four patients (11 women, 13 men; mean age, 65.0 years) with severe claudication, abnormal ankle-arm pressure indexes, and lesions in the superficial femoral or popliteal artery depicted at US underwent balloon PTA with US guidance. US findings were confirmed before and after PTA by means of intravenous digital subtraction angiography. RESULTS: All of 22 segmental stenoses and three of four superficial femoral artery occlusions were successfully treated (in 23 patients). In three cases, a residual stenosis was detected after initial PTA, and PTA was repeated with a larger balloon catheter. Of the 21 patients followed up for 6 months, one had reocclusion and three had hemodynamically significant restenosis. CONCLUSION: Results of PTA with US guidance in short stenoses or occlusions of the femoral or popliteal artery are similar to those of PTA with fluoroscopic control.

Aged↗

PubMed1996

Glutathione S-transferase M1 null genotype as a risk modifier for solvent-induced chronic toxic encephalopathy.

OBJECTIVES: Exposure to organic solvents increases the risk of neuropsychiatric disability or chronic toxic encephalopathy (CTE). Polymorphisms in the biotransformation of xenobiotics and solvents may influence individual susceptibility to develop toxic effects. In this study the problem of whether there could be any association between the glutathione S-transferase M1 (GSTM1) null genotype and the risk for CTE, with regard to solvent exposure, was investigated. METHODS: Sixty patients referred to a clinic because of some degree of psychiatric or neurological symptoms, as well as exposure to solvents, were examined by means of a validated questionnaire and psychometric testing. The degree of exposure to solvents was assessed by a thorough interview. According to clinical findings, the patients were classified into three categories as those with solvent-induced CTE, those with incipient CTE, and those who were non-CTE patients. Afterwards, leukocyte DNA (deoxyribonucleic acid) was isolated and the GSTM1 null genotype was determined by an assay based on polymerase chain reaction, blindly with regard to both exposure and disease status. RESULTS: The relative proportion (RP) of GSTM1 null genotypes was significantly increased for patients with a diagnosed CTE when they were compared with non-CTE patients (RP 2.55, 95% confidence interval 1.0-6.2). Dichotomizing the patients by high and low exposure revealed an increased risk for both GSTM1 gene carriers and the GSTM1 null genotype in the high-exposure group, the relative risks (RR) being 4.5 and 7.9, respectively. The chi-square for the Mantel extension for trend was 6.2 (P = 0.025). CONCLUSIONS: The GSTM1 null genotype acts as a risk modifier for CTE among patients occupationally exposed to solvents. The risk seems to increase in a dose-dependent fashion.

Brain Diseases↗

PubMed1996

[Leriche syndrome: treatment with local lysis and subsequent percutaneous transluminal angioplasty].

Two cases of Leriche's syndrome treated by local thrombolysis and subsequent percutaneous transluminal angioplasty with or without additional stent implantation are described. The fibrinolytic drugs were applied locally into the occlusions through a Mewissen Infusion Catheter and a Katzen Infusion Wire (initial 2.5 mg rt-PA as bolus followed by Urokinase (50000 IU/h) during 24 and 48 hours respectively. Residual stenotic lesions and occlusions were successfully treated with PTA alone in case 1 and with PTA in combination with a stent implantation in case 2. In accordance with Bean et al. (1985) and Goffette et al. (1989) we recommend local lysis in combination with PTA with or without additional stent implantation as an alternative treatment to surgery or systemic lysis for the treatment of Leriche's syndrome.

Adult↗

PubMed1995

Comparison of effects of high-dose and low-dose aspirin on restenosis after femoropopliteal percutaneous transluminal angioplasty.

BACKGROUND: Long-term treatment with aspirin is recommended in patients with large-vessel peripheral arterial disease since these patients have a high risk of death from cardiovascular causes. Recent studies have demonstrated the prophylactic effect of low-dose aspirin in reducing the risk of cardiovascular events. Since aspirin is also recommended for prevention of late recurrence after peripheral angioplasty, the present study was undertaken to compare the effects of high-dose (1000 mg/d) and low-dose (100 mg/d) aspirin on long-term patency after femoropopliteal angioplasty. METHODS AND RESULTS: Two hundred sixteen patients treated successfully by percutaneous transluminal angioplasty for femoropopliteal lesions were randomly allocated to therapy with either 1000 or 100 mg aspirin daily. The follow-up was 24 months. The long-term results were analyzed using the Kaplan-Meier method, and differences between curves of cumulative patency were determined with the Wilcoxon and log-rank statistics. Complete follow-up information (patency after 24 months, restenosis, and death) was obtained in 207 patients. During the 2-year follow-up period, 72 patients--36 in the high-dose and 36 in the low-dose aspirin group, respectively--developed angiographically verified reobstruction within the recanalized segment. By intention-to-treat analysis, the cumulative patency rates at 24 months were 62.5% in the high-dose and 62.6% in the low-dose aspirin group (Wilcoxon, P = .97; log-rank, P = .97). The cumulative survival at 24 months of follow-up was 86.6% in the high-dose and 87.7% in the low-dose aspirin group. The number of patients discontinuing therapy was 30 in the high-dose and 11 in the low-dose aspirin group (P < .01). Fewer patients receiving 100 mg of aspirin discontinued therapy because of gastrointestinal symptoms (4 versus 20). CONCLUSIONS: The data indicate that 100 mg aspirin is no less effective in the prevention of restenosis after femoropopliteal PTA than a 1000-mg dose and has fewer side effects.

Aged↗