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Biomedical subjects

N Ahmad

Publications and source records attributed to N Ahmad.

At least 145 records · Page 8Linked to original sources
PubMed1996

Seasonal variations in the semen quality of young British goats.

Physical characteristics of semen quality were studied over a 12 month period in 10 post pubertal, young male goats (7-19 months of age) maintained under the naturally prevailing climatic conditions characteristic of the South of England (latitude N 51 degrees 46'). Semen was collected fort-nightly using an artificial vagina and an ovariectomized, oestrogenized teaser doe. The physical appearance of the ejaculates varied from a yellow or whitish-yellow colour during September-December to a creamy-white colour during the remainder of the year. Ejaculate volume decreased from 0.96 +/- 0.06 ml in October to the minimum value of 0.39 +/- 0.03 ml in April and 0.38 +/- 0.02 ml in July, after which there was a sharp increase to the highest value, 1.04 +/- 0.05 ml, in September. Sperm cell concentration per ml was lowest (3.66 +/- 0.16 x 10(9)), during November and highest (6.56 +/- 0.29 x 10(9)) during May. However, the total sperm per ejaculate were highest during the September and lowest in December. The mass and individual motilities were higher during August-December than in the remainder of the year. The percentages of dead and morphologically abnormal spermatozoa were highest during May. The effect of the months and seasons of the year on all parameters of semen quality were significant (P < 0.01).

Animals↗
PubMed1996

Sexual maturity in British breeds of goat kids.

Eight male kids of British Sannen and one each of the British Alpine and British Toggenberg breed, born between the last week of February and first week of March 1990, were used. From the age of 12 weeks, they were monitored every week for body and testicular growth and sexual development, until they attained sexual maturity. The development of the sexual behaviour was a gradual process. From 12 weeks of age, the body weight increased at a constant rate. Testicular development, however, showed a biphasic pattern; the testis size increased rapidly between 12 and 20 weeks of age and was followed by a period of slow growth. Sexual maturity occurred at a mean age of 172.7 +/- 4.47 days, and at a mean body weight of 31.25 +/- 1.50 kg when the mean values of scrotal circumference, testis diameter and paired testes width were 24.13 +/- 0.47 mm, 54.01 +/- 1.26 mm and 88.31 +/- 1.61 mm, respectively. In most kids, the quality of the first ejaculate was good, although it varied widely between animals. It appeared that sexual maturity in British goat kids occurs at a younger age than in different breeds in other parts of the world that have been reported in the literature.

Age Factors↗
PubMed1996

The occurrence of hepatitis B and C viruses in Pakistani patients with chronic liver disease and hepatocellular carcinoma.

To study the occurrence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in patients with chronic liver disease (CLD) and hepatocellular carcinoma (HCC) in Pakistan, blood samples from 105 sequential patients with biopsy-proven CLD (n = 82) and HCC (n = 23) were tested for HBV and HCV markers. Of the 105, 87 (83%) had evidence of hepatitis B exposure, 58 (55%) were positive for hepatitis B surface antigen (HBsAg), 23 (22%) had hepatitis C antibodies and 25 (24%) had detectable HCV RNA. Significantly more patients with HCC had evidence of HBV exposure in the absence of HCV markers (49/82 vs. 20/23, odds ratio 4.49, 95% CI 1.17-25.16). The proportion of patients positive for HBsAg with no HCV markers was also significantly higher in the HCC group (34/82 vs. 18/23, odds ratio 5.08, 95% CI 1.59-18.96). There were more patients with only HCV markers in the CLD group than the HCC group but the difference was not statistically significant (19/82 vs. 1/23, odds ratio 6.63, 95% CI 0.93-288.01). A modified non-isotopic restriction fragment length polymorphism study on PCR products was used to investigate the epidemiology of HCV genotypes in Pakistan. Due to depletion of the initial samples, a second series of specimens collected one year afterwards was used. Fifteen out of 40 samples had amplifiable product and all were identified as type 3. A commercial serological typing method on the same samples also confirmed that type 3 was the predominant HCV genotype in Pakistan.

Adolescent↗
PubMed1996

Embryotoxicity of a regressing corpus luteum in beef cows supplemented with progestogen.

Postpartum cows with short-lived corpora lutea produce embryos that arrive at the uterus, but pregnancy rates are low even with exogenous progestogen. Four experiments were conducted to determine whether prostaglandin (PG) F2 alpha, known to cause early luteolysis, could have a direct effect on embryonic loss. Exogenous progestogen was injected s.c. twice daily in each experiment, starting 3 or 4 days after estrus (day of estrus = Day 0). Nonlactating, cycling beef cows were mated and injected i.m. every 8 h on Days 4 through 7 (experiment 1) or 5 through 8 (experiment 3) with either 15 mg PGF2 alpha or 3 ml saline. In experiment 1, cows in a third group received 1 g flunixin meglumine i.m. every 8 h. Ten of 18 PGF2 alpha-treated cows in experiment 3 were luteectomized on Day 5. Pregnancy rates were higher (p < 0.05) in cows given saline or flunixin meglumine (5 of 7) than in cows given PGF2 alpha (1 of 5) in experiment 1, and in cows given saline (6 of 9) or given PGF2 alpha, and luteectomized (8 of 10) than in cows given PGF2 alpha (2 of 8) in experiment 3. Postpartum beef cows, mated at weaning-induced first estrus, received i.m. injections every 8 h on Days 4 through 9 of 3 ml saline or 1 g flunixin meglumine (experiment 2); 14 flunixin meglumine-treated cows were luteectomized on Day 7. Pregnancy rates were higher in cows given flunixin meglumine and luteectomized (7 of 14) than in cows given saline (4 of 15) or flunixin meglumine alone (3 of 15; p < 0.05). In experiment 4, postpartum cows were luteectomized or sham-operated on Day 5. Pregnancy rates (2 of 13 and 2 of 14, respectively) did not differ. Thus, both reduction of endogenous PGF2 alpha and luteectomy were required for embryo survival in postpartum cows with short-lived corpora lutea, whereas luteectomy alone prevented effects of exogenous PGF2 alpha in cycling cows.

Animals↗
PubMed1996

Cytochrome P-450 and drug development for skin diseases.

Cytochromes P-450 (CYPs) are the most versatile and important class of drug-metabolizing enzymes which are induced in mammalian skin in response to xenobiotic exposure. CYPs are the target of special interest in the development of pharmaceuticals for skin diseases because most, if not all, drugs available in the armamentarium of the dermatologist are substrates, inducers or inhibitors of this enzyme family. The functional significance of drug metabolism in the skin and the implication of CYP in skin pathology and therapy is an area for future investigation. A detailed insight into the mechanism of action of various cutaneous CYPs, being capable of modulating the drug bioavailability, will be helpful in the development of better strategies for novel therapy against constantly increasing skin disorders. This brief review puts some of these perspectives together and suggests additional research in the area of CYPs with regard to their expression and modulation in mammalian skin as well as their implication in dermatological disorders and the therapy of skin diseases.

Aryl Hydrocarbon Hydroxylases↗
PubMed1996

Combined liver radiation and chemotherapy for palliation of hepatic metastases from colorectal cancer.

PURPOSE: To report the effects of boost dose radiation on palliation, survival, and toxicity in patients undergoing palliative treatment for hepatic metastases from colorectal cancers and to assess the potential benefits of higher doses of radiation to partial liver volumes. MATERIALS AND METHODS: Forty-five patients with hepatic metastases from colorectal cancers were treated with a course of palliative irradiation. Eligible patients included those with radiographically or histologically proven liver metastases. All patients but one received chemotherapy, either pretreatment (one patient) and/or concurrently with radiation (43 patients) via intravenous or hepatic intraarterial infusion. Patients were divided into two groups based on whether or not boost radiation was given. Thirty-three of the 45 patients (group 1) received whole-liver irradiation at doses that ranged from 8 to 31 Gy at 2.0 to 3.0 Gy per fraction (median dose, 21 Gy). The remaining 12 patients (group 2) received liver irradiation to 20 to 30 Gy followed by a boost dose to the area of dominant disease for a total dose of 33 to 60 Gy. The extent of liver involvement was similar between the two groups. Palliation, overall survival, and toxicity were analyzed with respect to radiation dose. RESULTS: There was no increase in acute effects observed in treating partial liver volumes to higher doses in conjunction with systemic chemotherapy. No cases of radiation-induced hepatitis or nephritis were documented. Hematologic toxicity (> or = grade 3) was observed in four patients with thrombocytopenia, three with leukopenia, and two with anemia. Pain was relieved in 71% and hepatomegaly in 59% of group 1 patients, as compared with 100% and 89%, respectively, of group 2 patients. Other symptoms such as nausea, fever, fatigue, and jaundice were palliated in 35% of group 1 and 90% of group 2 patients. The median survival time for group 1 patients was 4 months (range, 1 week to 26 months), which is consistent with that reported in the literature. The median survival time for group 2 patients was 14 months (range, 2 to 32 months) (P=.01). CONCLUSION: Standard hepatic irradiation followed by boost radiation to partial liver volumes in combination with chemotherapy is well tolerated without significant acute/late morbidity. Higher radiation doses to partial liver volumes offers improved palliative benefit and may prolong survival without an increase in morbidity.

Adult↗
PubMed1996

Exogenous pulses of luteinizing hormone cause persistence of the largest bovine ovarian follicle.

The objectives of this study were, 1) to determine whether increased frequency of LH pulses, independent of changes in progesterone, will cause persistence of the first largest ovarian follicle (LF1) during the bovine estrous cycle and 2) to determine whether a follicle produced in this manner will ovulate after luteal regression. In Exp. 1, 32 nonlactating beef cows were randomized into four groups. Bovine LH was given as 50 micrograms i.v. every 2 h from 0800 on d 7 through 0800 on d 13 postestrus to cows in two groups, which in addition either received PGF2 alpha on d 12 and were allowed to ovulate (LHOV; Group 1) or were ovariectomized (LHOVX; Group 2) on d 13. Cows in Group 3 received progesterone via a used controlled internal drug releasing device (CIDR) on d 4 to 13, PGF2 alpha on d 6, and ovariectomy on d 13. These cows received 1 mL of saline i.v. every 2 h on d 7 to 13, as did those in Group 4 (SAL), but cows in Group 4 did not receive any PGF2 alpha. Proportion (percentage) of LF1 maintained until d 13 was similar in cows with CIDR (100) and on LH (88) but less in cows on SAL (36; P < .01). The LF1 were largest in cows with CIDR, smallest in cows on SAL, and intermediate in cows on LH (P < .001). During d 7 to 13, progesterone was lesser and estradiol was greater in peripheral plasma in cows with CIDR than in cows on LH or SAL (P < .001). In Experiment 2, beef heifers received 50 micrograms of bLH (LH; n = 5) or saline (SAL; n = 4) i.v. every 2 h from 0800 on d 7 until 12 h after signs of estrus were observed following PGF2 alpha on d 12. The LF1 were maintained by LH and 60% ovulated; all LF1 were replaced during treatment in heifers on SAL. The LF1 were larger in heifers on LH, but estradiol and progesterone did not differ between groups. In conclusion, an increased frequency of LH pulses during a normal luteal phase allowed LF1 to persist but did not increase secretion of estradiol.

Animals↗
PubMed1996

Breast carcinoma in Pakistani women.

In many developed and developing countries including Pakistan, breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in women. Among 4575 women presenting to the Cancer Research Foundation of Pakistan between 1987 and 1994 with breast lumps, 1201 (26%) were found to have breast cancer. Their ages ranged from 19 to 79 years. The peak incidence was in the 30 to 39 age group. Most patients were multiparous with an average of five children. The size of the tumor was greater than 5 cm in 66% of the cases. Invasive ductal carcinoma was the most common morphological type. According to the Bloom and Richardson grading system, 58% of cases were grade III. Lymph node metastases were present in 73% of the cases.

Adult↗
PubMed1995

A clinical and ultrasonographic study of the testes and related structures of goats and rams after unilateral vasectomy.

The semen quality, plasma testosterone concentrations and ultrasonographic changes were studied for up to 20 weeks after the unilateral vasectomy of two adult goats and two rams, and the gross and histological changes were examined post mortem. An intact ram and an intact goat served as controls. There was a marked decrease in the sperm concentration and the total numbers of sperm per ejaculate in both species. However, there seemed to be no effect on ejaculatory volume, mass motility and individual motile sperm, percentages of dead and abnormal sperm and plasma concentrations of testosterone. Ultrasonographically, the epididymal tail lost its characteristic heterogeneous texture and appeared enlarged. Anechoic masses, representing sperm granulomata, were visible within the epididymal tail of both the rams, and the epididymal head of one of the goats and at the cut end of the vas deferens in the other. They were observed as early as four to six weeks after surgery and their nature was confirmed post mortem. The sequential ultrasonographic changes in the testis and the epididymis are described.

Animals↗
PubMed1995

Fatty acid binding to bovine serum albumin prevents formation of intermediate during denaturation.

Urea-induced denaturation of defatted BSA and BSA containing six mol palmitic acid/mol protein (fatted BSA) has been studied by the techniques of UV difference spectroscopy and fluorescence spectroscopy. The notable differences between the two transitions are a shift in the transition of fatted BSA to a higher urea concentration and a three-state denaturation transition in defatted BSA compared to an apparent two-state denaturation transition in fatted BSA. The stable denaturation intermediate in defatted BSA occurs at 4.5-5.0 M urea, a urea concentration at which denaturation in fatted BSA has not yet started. These results are further supported by the difference spectral results obtained at 4.5 M urea in the two albumin preparations. The occurrence of denaturation intermediate only in defatted BSA and the presence of the two strong fatty-acid-binding sites in domain III lead us to conclude that this domain is relatively unstable in the absence of fatty acids and is responsible for the formation of intermediate.

Fatty Acids↗
PubMed1995

Absence of hepatitis B and C viruses in pediatric idiopathic membranoproliferative glomerulonephritis.

The blood-borne hepatitis viruses, hepatitis B virus (HBV) and hepatitis C virus (HCV), have similar epidemiological features. The association of chronic HBV infection and glomerulonephritis is well established, particularly in children. Recent reports have shown an association between HCV infection and glomerulonephritis in adults. In order to assess the role of these hepatotropic viruses in membranoproliferative glomerulonephritis (MPGN) we screened 34 children with idiopathic MPGN for the presence of HBV and HCV infection using highly sensitive polymerase chain reaction techniques for the detection of HBV DNA and HCV RNA. Also, enzyme-linked immunosorbent assays were used to detect the presence of antibody to hepatitis B surface antigen and antibody to HCV. No evidence of HBV or HCV infection was demonstrated in any of the patients. We conclude that HBV and HCV are not significant causes of idiopathic MPGN in children in the United States.

Adolescent↗
PubMed1995

Effect of persistent follicles on early embryonic losses in beef cows.

Low doses of progestogens in regimens for synchronization of estrus result in persistent follicles (PF) and reduced conception rates in cattle. The effects of PF on recovery of oocytes/embryos, fertilization, and embryonic development were examined in beef cows. To produce PF, cows received a used Controlled Internal Drug Releasing device on Days 4 through 13 after pretreatment estrus (Day 0) and two injections of 20 mg prostaglandin (PG) F2 alpha, i.m., 12 h apart on Day 6 (PF; n = 20). Control cows received only PGF2 alpha on Day 6 so they would ovulate growing follicles (GF; n = 22). With this model, the largest (dominant) follicle from the first wave of follicular development was being ovulated in cows in each group. Cows were observed for estrus twice daily and were then mated to highly fertile bulls. Follicular development was monitored by ultrasonography on alternate days from Day 2 until estrus and then daily until apparent ovulation. Jugular blood samples were collected every other day from Day 2 through 6 days after mating at posttreatment estrus, when uteri were flushed nonsurgically. The ovulatory follicle, which was followed retrospectively and had been observed longer (14 +/- 1 vs. 8 +/- 1 days), was larger in PF (17.2 +/- 0.5 mm) than in GF (14.5 +/- 0.6 mm; p < 0.01). Mean estradiol-17 beta (E2) in jugular plasma during the 6 days before estrus was higher in PF than in GF (5.7 +/- 0.4 vs. 2.6 +/- 0.4 pg/ml; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Genetic analysis of human immunodeficiency virus type 1 envelope V3 region isolates from mothers and infants after perinatal transmission.

The human immunodeficiency virus type 1 (HIV-1) sequences from variable region 3 (V3) of the envelope gene were analyzed from seven infected mother-infant pairs following perinatal transmission. The V3 region sequences directly derived from the DNA of the uncultured peripheral blood mononuclear cells from infected mothers displayed a heterogeneous population. In contrast, the infants' sequences were less diverse than those of their mothers. In addition, the sequences from the younger infants' peripheral blood mononuclear cell DNA were more homogeneous than the older infants' sequences. All infants' sequences were different but displayed patterns similar to those seen in their mothers. In the mother-infant pair sequences analyzed, a minor genotype or subtype found in the mothers predominated in their infants. The conserved N-linked glycosylation site proximal to the first cysteine of the V3 loop was absent only in one infant's sequence set and in some variants of two other infants' sequences. Furthermore, the HIV-1 sequences of the epidemiologically linked mother-infant pairs were closer than the sequences of epidemiologically unlinked individuals, suggesting that the sequence comparison of mother-infant pairs done in order to identify genetic variants transmitted from mother to infant could be performed even in older infants. There was no evidence for transmission of a major genotype or multiple genotypes from mother to infant. In conclusion, a minor genotype of maternal virus is transmitted to the infants, and this finding could be useful in developing strategies to prevent maternal transmission of HIV-1 by means of perinatal interventions.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Exacerbation of nickel induced oxidative response by vitamin E.

Vitamin E (alpha-tocopherol), a well known naturally occurring chain breaking antioxidant and a free radical scavenger was found to exacerbate nickel (Ni) toxicity in mice. Vitamin E (Vit. E) mediated enhancement of nickel toxicity was demonstrated by (i) enhanced mortality in mice treated with Ni and Vit. E (ii) increased hepatic lipid peroxidation, (iii) increased rate of benzoate hydroxylation, and (iv) liposomal membrane damage.

Animals↗
PubMed1995

Reduction of cis-platinum induced nephrotoxicity by zinc histidine complex : the possible implication of nitric oxide.

Cisplatin is a prominent member of the effective broad spectrum antitumor drugs. The clinical usage of cisplatin is, however, restricted due to some adverse side effects including renal toxicity. The present study demonstrates the protective effect of a Zinc-chelate of histidine, [Zn-Hist], against cisplatin induced nephrotoxicity and gastrointestinal toxicity as shown by decreases in BUN, creatinine and lower incidence of diarrhoea. The observed inhibition in cisplatin induced renal and hepatic lipid peroxidation by [Zn-Hist] pretreatment, suggests an importance for Zn in stabilisation of membrane integrity probably through the displacement of the redox-active metals that may be responsible for inducing peroxidative damage at target sites. The findings also suggest that cisplatin may play biochemical role in arginine-metabolism including nitric oxide (NO) production.

Animals↗
PubMed1995

Breast cancer in pregnant and lactating women.

Between 1988 and 1991, we treated 595 women with breast cancer in the Breast Disease Section of the Cancer Research Foundation of Pakistan. We report here on 61 patients who were pregnant or lactating. Most patients presented at a late stage of disease because of ignorance, social taboos, or fear of hospitalization and operation. The largest diameter of the breast mass at presentation was 15 cm. Lymph nodes were involved in 70.5% of cases. Multiparity, young marriages, malnutrition, and unhygienic conditions are ripe in the rural environment of Pakistan. No oral contraceptives are used. Modern and conventional methods of treatment did not increase the survival rate of these cancer patients.

Adult↗
PubMed1994

Radiation doses in Pakistani houses.

Natural radioactivity in building materials has been measured to determine the external dose equivalent rate due to walls, floor and ceiling. Indoor radon has been measured to estimate the internal dose rate. Occupancy factor was estimated to be 0.3. It is found that the external dose equivalent rate to lungs is less than or equal to the internal dose equivalent rate. Both the external and internal dose equivalent rates in the houses under consideration are less than the background dose equivalent rate value given by UNSCEAR.

Air Pollution, Indoor↗