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Biomedical subjects

A F Ahmed

Publications and source records attributed to A F Ahmed.

16 recordsLinked to original sources
PubMed2005

Abomasal cannulation in the milk-fed calf using a 7 mm polyurethane tube.

The main objective of this study was to develop a simple and effective surgical technique for abomasal cannulation in neonatal calves. General anaesthesia was induced in 12, 3-day-old male dairy calves and a polyurethane cannula surgically implanted in the abomasal body (n = 12) and pyloric antrum (n = 6) through a right paracostal incision. Fifteen cannulae remained in situ from day 3 to 34 of life (mean: 29 days), and three cannulae were extruded 13-14 days after placement. Calves were clinically healthy and gained weight during the study. Cannulae were well tolerated by the calves and abomasal contents did not leak from the cannula sites. Necropsy examination revealed firm adhesions between the abomasum and parietal peritoneum at the cannula sites with no evidence of leakage or peritonitis. We conclude that surgical placement of polyurethane tubes designed for percutaneous endoscopic gastrostomy provided a useful method for cannulation of the abomasum of neonatal calves. The cannulation technique can be used for experimental studies, as well as for nutritional and fluid support of sick calves that cannot be managed by oral treatment.

Abomasum↗
PubMed2005

Effect of orally administered omeprazole on abomasal luminal pH in dairy calves fed milk replacer.

The objective of this study was to determine whether oral administration of omeprazole, a proton-pump inhibitor, increased abomasal luminal pH in calves fed milk replacer. Four male dairy calves with cannulae in the abomasal body suckled milk replacer (60 ml/kg body weight every 12 h) and were administered a non-enteric-coated omeprazole (4 mg/kg body weight every 24 h) in a paste formulation for five successive days. Abomasal luminal pH was continuously measured using miniature glass pH electrodes. On the first day of omeprazole administration, there was a significant (P<0.05) increase in mean 24-h pH from 2.89 to 4.17. The mean 24-h pH on days 2, 3, 4 and 5 of omeprazole administration were 3.85, 4.02, 3.97 and 3.39 respectively. We conclude that oral administration of non-enteric-coated omeprazole increased abomasal luminal pH in calves fed milk replacer, but that the effect may decrease over time.

Abomasum↗
PubMed2004

The prevalence of MADH4 and BMPR1A mutations in juvenile polyposis and absence of BMPR2, BMPR1B, and ACVR1 mutations.

BACKGROUND: Juvenile polyposis (JP) is an autosomal dominant syndrome predisposing to colorectal and gastric cancer. We have identified mutations in two genes causing JP, MADH4 and bone morphogenetic protein receptor 1A (BMPR1A): both are involved in bone morphogenetic protein (BMP) mediated signalling and are members of the TGF-beta superfamily. This study determined the prevalence of mutations in MADH4 and BMPR1A, as well as three other BMP/activin pathway candidate genes in a large number of JP patients. METHODS: DNA was extracted from the blood of JP patients and used for PCR amplification of each exon of these five genes, using primers flanking each intron-exon boundary. Mutations were determined by comparison to wild type sequences using sequence analysis software. A total of 77 JP cases were sequenced for mutations in the MADH4, BMPR1A, BMPR1B, BMPR2, and/or ACVR1 (activin A receptor) genes. The latter three genes were analysed when MADH4 and BMPR1A sequencing found no mutations. RESULTS: Germline MADH4 mutations were found in 14 cases (18.2%) and BMPR1A mutations in 16 cases (20.8%). No mutations were found in BMPR1B, BMPR2, or ACVR1 in 32 MADH4 and BMPR1A mutation negative cases. DISCUSSION: In the largest series of JP patients reported to date, the prevalence of germline MADH4 and BMPR1A mutations is approximately 20% for each gene. Since mutations were not found in more than half the JP patients, either additional genes predisposing to JP remain to be discovered, or alternate means of inactivation of the two known genes are responsible for these JP cases.

Activin Receptors, Type I↗
PubMed2002

Germline SMAD4 or BMPR1A mutations and phenotype of juvenile polyposis.

BACKGROUND: Juvenile polyposis (JP) is an inherited condition predisposing to upper gastrointestinal (UGI) polyps and colorectal cancer. Two genes are known to predispose to JP, SMAD4 and bone morphogenetic protein receptor type 1A (BMPR1A). The object of this study was to determine the differences in phenotype of patients with SMAD4 or BMPR1A mutations (MUT+) compared with those without (MUT-). METHODS: DNA was extracted from 54 JP probands and used for polymerase chain reaction of all exons of SMAD4 and BMPR1A. Products were then sequenced and analyzed for mutations. Medical record data were used to create a JP database, and statistical analysis was performed using Fisher's exact and unpaired t-tests. RESULTS: Nine of 54 patients had germline SMAD4 mutations, 13 had BMPR1A mutations, and 32 had neither. There were no significant differences between SMAD4+ and BMPR1A+ cases in terms of clinical factors examined, except for a family history of UGI involvement (P <.01). There was a higher prevalence of familial cases in MUT+ patients (P =.09), >10 lower gastrointestinal polyps (P =.06), and frequency of family history of gastrointestinal cancer compared with MUT- patients (P =.01). CONCLUSIONS: Patients with germline SMAD4 or BMPR1A mutations have a more prominent JP phenotype than those without, and SMAD4 mutations predispose to UGI polyposis.

Adolescent↗
PubMed2002

Effect of feeding frequency and route of administration on abomasal luminal pH in dairy calves fed milk replacer.

The aim of this study was to determine the effect of feeding frequency and route of administration on abomasal luminal pH in suckling calves. Six male dairy calves with cannulae in the abomasal body were administered the following six treatments in a randomized crossover design: 24 h fasting, suckling of a high-quality milk replacer (all-milk protein; 12% of body weight [BW]/d) at 12-h (2x), 8-h (3x), 6-h (4x), and 3-h (8x) intervals, and ruminal intubation of milk replacer (12% of body weight/day) at a 12-h (2x) interval. Abomasal luminal pH was measured every second for 24 h with miniature glass pH electrodes. Least squares mean 24-h fasting abomasal luminal pH was 1.73, whereas mean 24-h pH after suckling and intubation of milk replacer every 12 h were higher at 3.44 and 3.17, respectively. Increasing the frequency of milk replacer suckling to 3x, 4x, and 8x increased mean 24-h abomasal luminal pH; however, there was no difference in mean 24-h pH between 3x (3.69), 4x (3.64), and 8x (3.67) suckling. The percentage of the 24-h recording period that abomasal luminal pH was > 3.0 was 0, 49, 53, 61, 61, and 71% for fasting, 2x intubation of milk replacer, and 2x, 3x, 4x, and 8x suckling of milk replacer, respectively. Increasing the frequency of milk replacer suckling may be efficacious in the prophylaxis of abomasal ulceration in milk-fed calves.

Abomasum↗
PubMed2001

CD8+ T cells infiltrating into bile ducts in biliary atresia do not appear to function as cytotoxic T cells: a clinicopathological analysis.

It is speculated that immune mechanisms are involved in bile duct damage in biliary atresia (BA), as in primary biliary cirrhosis (PBC). In BA, however, no reports have described the in situ distribution of cytotoxic T lymphocytes (CTLs) using specific markers, nor has the clinical association been clarified. The present study describes the immunohistochemical distribution of CD8+ T cells and the relevant markers [perforin, granzyme B, FasL (CD95L)] in 47 cases of BA operated upon at days 12-79. The results were compared with those of PBC. In BA, CD8+ T cells infiltrated bile ducts in a way similar to that observed in PBC. However, in sharp contrast to PBC, none of the inflammatory cells infiltrating into the bile ducts in BA expressed cytotoxic markers such as perforin, granzyme B, or Fas ligand (FasL). Clinical follow-up of patients with BA revealed that a greater degree of infiltration of bile ducts by CD8+ T cells is associated with better liver function. Taken together, these data suggest the absence of direct CTL activity against bile ducts in BA in the postnatal period.

Adolescent↗
PubMed2001

Clinical significance of c-kit expression in biliary atresia.

The aim of the present study was to examine the clinical significance of c-kit expression in biliary atresia (BA) using formalin-fixed, paraffin-embedded sections from 21 patients with BA. Patients were divided into group I (n = 8) with good liver function; group II (n = 8) with moderate liver dysfunction; and group III (n = 5) with severe liver dysfunction. Choledochal cysts (CDC, n = 5) and normal liver samples (NL, n = 4) served as controls. The results were analyzed and compared among the groups. Most c-kit+ cells were present in the portal tracts, and their numbers in BA were significantly higher than in the controls (11.12 +/- 1.64 vs 2.15 +/- 0.15 [mean +/- standard error], P = 0.02, BA vs CDC; 11.12 +/- 1.64 vs 1.66 +/- 0.52, P = 0.03, BA vs NL). Clinical correlation revealed a significantly higher number of c-kit+ cells in group III versus group I (18.10 +/- 3.62 vs 8.86 +/- 2.51, P = 0.02). These results suggest that c-kit overexpression is associated with an adverse clinical outcome in BA.

Biliary Atresia↗
PubMed2001

In situ CD14 expression in biliary atresia: comparison between early and late stages.

PURPOSE: The aim of this study was to compare the in situ expression of CD14 between early and late stage of biliary atresia (BA) to determine if a time course of CD14 expression exists in BA. METHODS: Immunohistochemical analysis of membrane-bound CD14 expression was carried out in periodate-lysine-paraformaldehyde (PLP)-fixed frozen sections from 9 early- (obtained during Kasai procedure) and 6 late- (obtained during liver transplantation) stage cases of BA. Normal liver (n = 3) and choledochal cysts (n = 5) served as normal controls and disease controls respectively. RESULTS: In the early stage, 6 patients (66.66%) showed extensive CD14 expression (grade 3 [G(3)], more than 50% positive cells), whereas no CD14-positive cells could be detected in 4 patients (66.66%) in the late stage. In both stages, most of the positive cells were observed in the parenchyma of the hepatic lobules where Kupffer cells and sinusoidal endothelial cells stained positive. Arterial and venous endothelium, bile duct cells, and hepatocytes were negative for CD14. Double immunohistochemistry in the early stage showed a higher colocalization rate of CD14 and CD68 in the sinusoidal locations (33.69 +/- 9.270% [mean +/- SEM]) than in the portal tract (7.6+/-4.64% [mean +/- SEM]; P<.05). Similar pattern of colocalization also was observed in the late stage. In the normal controls no expression of CD14 could be detected, whereas in the disease controls only 1 case showed mild expression (grade 1 [G(1)], 1% to 10% positive cells) and the rest showed no expression of CD14. CONCLUSION: These results suggest that CD14 expression in BA is a dynamic phenomenon having time-related change with overexpression in the early stage and reduced expression in the late stage.

Adolescent↗
PubMed2001

Effect of orally administered cimetidine and ranitidine on abomasal luminal pH in clinically normal milk-fed calves.

OBJECTIVE: To characterize the change of pH in the abomasal lumen throughout a 24-hour period, to determine whether pH of the abomasal body differs from pH of the pyloric antrum, and to determine whether oral administration of cimetidine and ranitidine alters pH of the abomasal lumen in milk-fed calves. ANIMALS: 5 male dairy calves (4 Holsteins-Friesian, 1 Ayrshire), 5 to 15 days old. PROCEDURE: Cannulas were surgically positioned in the abomasal body and pyloric antrum of each calf. Calves received the following treatments in a randomized crossover design: milk replacer (60 ml/kg of body weight, q 12 h [untreated control calves]), milk replacer and cimetidine (50 or 100 mg/kg, q 8 h), or milk replacer and ranitidine (10 or 50 mg/kg, q 8 h). The pH of the abomasal body and pyloric antrum was measured for 24 hours, using miniature glass pH electrodes. RESULTS: Suckling of milk replacer immediately increased abomasal luminal pH from 1.4 to 6.0, followed by a gradual decrease to preprandial values by 6 hours. Preprandial and postprandial pH values were not significantly different between the abomasal body and pyloric antrum, indicating lack of pH compartmentalization in the abomasum of milk-fed calves. Administration of cimetidine and ranitidine caused a significant dose-dependent increase in mean 24-hour abomasal luminal pH. CONCLUSIONS AND CLINICAL RELEVANCE: Abomasal acid secretion in milk-fed calves is mediated in part by histamine type-2 receptors. Cimetidine and ranitidine may be efficacious in the treatment of abomasal ulcers in milk-fed calves.

Abomasum↗
PubMed1997

Phytochemical analysis of Geigeria alata and Francoeuria crispa essential oils.

Phytochemical analyses of Geigeria alata (Benth. & Hook.) and Francoeuria crispa (Forssk., Cas.) (Asteraceae) essential oils were performed. G. alata oil showed moderate in vitro cytotoxicity (IC50, micrograms/ml against tumor cells; P388: 2.0, A-549: 2.5 and HT-29: 5.0), and also showed weak anti-HIV activity. S-Carvotanacetone, the major component of F. crispa oil (93.0%), was isolated and its structure was elucidated by 2D-NMR analysis.

Animals↗
PubMed1993

A pilot study of diet and gallstone formation in young Saudi women.

The diet of 100 younger than 40 years Saudi females; 50 cases with gallstones and 50 control mean age and SD 30.2 (6.1) and 29.7 (6.4) years respectively, was studied by taking a qualitative dietary history. There was no significant difference between the dietary intake of the 2 groups with regard to cholesterol-rich food and animal fat-rich foods, high fibre foods and the consumption of fast food. However, dates, 'kabsah', 'modabi' and cheese were consumed significantly more by cases (P-value < .001, < .046, < .001 and < .004 respectively) and vegetable oil was used more by controls for cooking purposes (P-value < .05).

Adult↗
PubMed1991

Imerslund-Gräsbeck syndrome in a Saudi family.

Imerslund-Gräsbeck syndrome, an autosomal recessive trait of defective uptake of intrinsic factor-vitamin B12 complex by terminal ileum, is described in a Saudi family (two siblings and their first cousin). This rare disease has previously been reported only in Northern Europe and North African Jewish ethnic groups.

Adolescent↗
PubMed1990

Preliminary experience with extracorporeal shock-wave lithotripsy monotherapy and bladder calculi.

During the period November 1988 to April 1989, eleven patients with bladder calculi, seen at our Centre, were offered ESWL therapy. However, only eight patients underwent ESWL. One patient passed his stone spontaneously, one requested endoscopic lithotrity as the initial mode of therapy and one underwent transurethral resection of the prostate and simultaneous endoscopic lithotrity of his bladder calculus. This series, though admittedly, small, nevertheless serves to introduce a safe and expeditious modality for the removal of bladder calculi. A high degree of patient acceptance and no treatment failures embolden us to advocate this modality as initial therapy for bladder calculi.

Adult↗