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H Hassan

Publications and source records attributed to H Hassan.

At least 55 records · Page 3Linked to original sources
PubMed1997

Expression of three UDP-N-acetyl-alpha-D-galactosamine:polypeptide GalNAc N-acetylgalactosaminyltransferases in adenocarcinoma cell lines.

The levels of mRNA expression of three UDP-N-acetyl-alpha-D-galactosamine:polypeptide GalNAc N-acetylgalactosaminyltransferases (GalNAc-transferases) were quantified for human adenocarcinoma cell lines from pancreas, colon, stomach, and breast. Two of the GalNAc-transferases, GalNAc-T1 and GalNAc-T2, were expressed constitutively and at low levels in most or all cell lines examined. A third GalNAc-transferase, GalNAc-T3, was differentially expressed. Well-differentiated adenocarcinoma cell lines expressed high levels and moderately differentiated cell lines expressed lower levels of GalNAc-T3. Cell lines classified as poorly differentiated failed to express GalNAc-T3 mRNA at levels that could be detected by Northern blot analysis. Differential expression of the GalNAc-T3 protein was confirmed in these cell lines by Western blotting. We propose that glycosylation in tumor cell lines may be regulated in part by differential expression of GalNAc-transferases, and we suggest that GalNAc-T3 gene expression may be a molecular indicator of differentiated adenocarcinoma.

Actins↗
PubMed1997

Substrate specificities of three members of the human UDP-N-acetyl-alpha-D-galactosamine:Polypeptide N-acetylgalactosaminyltransferase family, GalNAc-T1, -T2, and -T3.

Mucin-type O-glycosylation is initiated by UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc-transferases). The role each GalNAc-transferase plays in O-glycosylation is unclear. In this report we characterized the specificity and kinetic properties of three purified recombinant GalNAc-transferases. GalNAc-T1, -T2, and -T3 were expressed as soluble proteins in insect cells and purified to near homogeneity. The enzymes have distinct but partly overlapping specificities with short peptide acceptor substrates. Peptides specifically utilized by GalNAc-T2 or -T3, or preferentially by GalNAc-T1 were identified. GalNAc-T1 and -T3 showed strict donor substrate specificities for UDP-GalNAc, whereas GalNAc-T2 also utilized UDP-Gal with one peptide acceptor substrate. Glycosylation of peptides based on MUC1 tandem repeat showed that three of five potential sites in the tandem repeat were glycosylated by all three enzymes when one or five repeat peptides were analyzed. However, analysis of enzyme kinetics by capillary electrophoresis and mass spectrometry demonstrated that the three enzymes react at different rates with individual sites in the MUC1 repeat. The results demonstrate that individual GalNAc-transferases have distinct activities and the initiation of O-glycosylation in a cell is regulated by a repertoire of GalNAc-transferases.

Amino Acid Sequence↗
PubMed1997

Acute pancreatitis in Sowetan Africans. A disease with high mortality and morbidity.

CONCLUSION: In African blacks, acute pancreatitis requiring hospital admission is a severe disease associated with a high mortality and significant long-term morbidity in surviving patients. BACKGROUND: It has been suggested that acute pancreatitis has a benign course in Africans in contrast to Western populations. The aim of the present study was to ascertain the incidence of acute pancreatitis at Baragwanath Hospital for a 1-yr period and to test the validity of the above hypothesis. METHODS: One hundred thirty-six patients with acute pancreatitis were retrospectively assessed. Fifty patients were available for a prospective follow-up examination and underwent sonographic and biochemical investigations. Acute pancreatitis was diagnosed if the patient presented with the typical clinical picture and a raised serum amylase level > 800 U/L. RESULTS: The study consisted of 108 male and 28 female patients. Alcohol was identified as the predominant etiologic factor in 83.1%, biliary disease in 7.4%, and idiopathic causes in 6.6%. Substantial morbidity was encountered in 32.3% and was caused mainly by pancreatic complications, metabolic derangements, alcohol-related symptoms, and respiratory impairment. A portion (10.3%) of the patients developed further pancreatic pathology, such as pseudocysts, necroses, or an abscess. The overall mortality rate was 8.1%. Patients who died had a higher mean serum amylase, and most deaths occurred within 2 d of admission. Prospective follow-up after an average of 9.3 mo revealed serious morbidity in two-thirds of patients. Fifty-two percent suffered from severe abdominal pain, 36% complained of weight loss, and 18% were shown to have a sonographically abnormal pancreas. Fecal chymotrypsin levels indicated exocrine pancreatic impairment in 30.6%.

Acute Disease↗
PubMed1996

cDNA cloning and expression of a novel human UDP-N-acetyl-alpha-D-galactosamine. Polypeptide N-acetylgalactosaminyltransferase, GalNAc-t3.

The glycosylation of serine and threonine residues during mucin-type O-linked protein glycosylation is carried out by a family of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (GalNAc-transferase). Previously two members, GalNAc-T1 and -T2, have been isolated and the genes cloned and characterized. Here we report the cDNA cloning and expression of a novel GalNAc-transferase termed GalNAc-T3. The gene was isolated and cloned based on the identification of a GalNAc-transferase motif (61 amino acids) that is shared between GalNAc-T1 and -T2 as well as a homologous Caenorhabditis elegans gene. The cDNA sequence has a 633-amino acid coding region indicating a protein of 72.5 kDa with a type II domain structure. The overall amino acid sequence similarity with GalNAc-T1 and -T2 is approximately 45%; 12 cysteine residues that are shared between GalNAc-T1 and -T2 are also found in GalNAc-T3. GalNAc-T3 was expressed as a soluble protein without the hydrophobic transmembrane domain in insect cells using a Baculo-virus vector, and the expressed GalNAc-transferase activity showed substrate specificity different from that previously reported for GalNAc-T1 and -T2. Northern analysis of human organs revealed a very restricted expression pattern of GalNAc-T3.

Amino Acid Sequence↗
PubMed1995

Nephrotoxicity of Narthecium ossifragum in cattle in Norway.

During the summer of 1992 renal failure was diagnosed in 232 grazing cattle in 85 herds on the west coast of Norway. The salient clinical signs were depression, anorexia and melaena or fresh blood in the faeces; diarrhoea was also commonly observed. The serum concentrations of creatinine, urea, magnesium and phosphorus, and the activities of glutamate dehydrogenase, aspartate aminotransferase and creatine kinase were above normal and the serum calcium concentration was below normal. Post mortem examinations consistently revealed renal tubular necrosis. In some cases there was liver necrosis and also erosions at the base of the tongue, in the oesophagus and in the jejunum and colon. The toxicity was probably caused by the plant Narthecium ossifragum (bog asphodel).

Animals↗
PubMed1995

A preliminary report on urinary BT-PABA/PAS excretion index, serum pancreatic isoamylase and faecal chymotrypsin tests of pancreatic dysfunction in Sowetan Africans.

The steady increase in chronic pancreatitis among black Africans at Soweto, RSA, in the past 40 years necessitates an objective and non-invasive test to detect the disease at an early stage. Given the biphasic nature of the disease--secretory hyperfunction with periodic active inflammatory episodes followed by steady exocrine impairment--we assessed three potential aids. Urinary BT-PABA/PAS excretion index (PEI), serum pancreatic isoamylase (PIA) and faecal chymotrypsin activity (FCA) were measured in the following groups: 16 outwardly healthy hospital workers, 16 consecutive patients with calcifying chronic pancreatitis and 19 with abdominal pain ascribed to other conditions (disease controls). (1) Healthy controls had lower PEI than those at Manchester, UK, or Madras, India, from subclinical acinar loss--as shown by lower PABA recovery whereas intestinal absorptive capacity was maintained, as shown by recovery of PAS. (2) Using the popular cut-off for PEI (0.75) only 9 of 14 patients with chronic pancreatitis were identified (sensitivity 64%, 2 tests unsatisfactory), while a value of less than 0.54, the mean -2 S.D. in local controls, yielded sensitivity of 50%. (3) If PEI of less than 0.75 or PIA outside the reference range was taken to indicate the disease, 5 of 9 disease controls would have been classed as chronic pancreatitis (among those with both tests satisfactory): retrospective ultrasound scans did not identify these. (4) Although FCA was less than the preselected cut-off, 5 units/g, in every patient with chronic pancreatitis (100% sensitivity) its poor predictive value was indicated by low specificity: subnormal levels in 4 of 14 and 6 of 16 healthy controls or disease controls, respectively, most of whom had near-normal values of PEI, PIA or both. (5) Collectively, these results suggest a high frequency of subclinical chronic pancreatitis at Soweto, but also that the combination of tests required to identify it may prove impractical--whether in field surveys or hospital practice.

4-Aminobenzoic Acid↗
PubMed1995

Fecal short chain fatty acids in South African urban Africans and whites.

UNLABELLED: Diminished levels for fecal short chain fatty acids (SCFAs) have been linked to occurrence of ulcerative colitis, colorectal polyps, and colon cancer, diseases that are rare or uncommon in African populations. PURPOSE: The aim of this study was to determine fecal SCFA concentrations and fecal pH values in groups of black South Africans (African) and white South Africans (white) subjects. METHODS: Twenty healthy Africans (all women; mean age, 35 years) and 17 healthy whites (7 women; 10 men; mean age, 32 years) were tested. RESULTS: Mean total concentrations of SCFAs in the two groups were 142.1 (+/- 53.9) and 69.2 (+/- 26.0) mmol/kg wet feces, respectively (P = 0.0001). Mean values for Africans were significantly higher in all subfractions except butyrate. There was a significant inverse correlation between fecal pH value and total fecal SCFA concentration (r = 0.704; P = 0.001). CONCLUSION: High concentrations of fecal SCFAs in the African group could protect against chronic bowel diseases.

Adult↗
PubMed1994

A surprising effect of extraction conditions on the mobility of some plant virus coat proteins in SDS-PAGE.

The coat protein from purified particles of pea seedborne mosaic potyvirus (PSbMV) moves in SDS-PAGE with an apparent molecular weight (M(r)) of 36 kDa. However, extracts of PSbMV infected plants prepared with SDS or urea contain PSbMV immunoreactive proteins with apparent M(r) 39 kDa as well as 36 kDa. The low mobility form may be generated from the apparent M(r) 36 kDa form by incubating purified PSbMV particles with healthy plant sap in the presence of denaturing agents. A similar effect is observed with bean yellow mosaic potyvirus, but not with three viruses outside the potyvirus group. Experiments suggest that a soluble plant enzyme is responsible for the conversion, which apparently takes place only in vitro under denaturing conditions. This phenomenon may lead to erroneous conclusions about the M(r) of some viral coat proteins. However, the conversion can be prevented by heat treatment of the plant tissue prior to extraction.

Capsid↗
PubMed1994

Stool weight and faecal pH in two South African populations with a dissimilar colon cancer risk.

Bowel diseases (appendicitis, diverticulitis and colon cancer) in South African whites and populations of prosperous Western countries are similar. Among rural South African blacks with a traditional lifestyle these diseases are very uncommon or almost unknown. A study was undertaken to measure stool weight and faecal pH in South African urban blacks and whites. There was no difference in stool weight, but the faecal pH was significantly higher in whites (P = 0.002).

Adult↗
PubMed1994

Clostridium septicum septicaemia in a patient with leukaemia.

Clostridium septicum infection has been shown to have a strikingly high association with either bowel or blood malignancies. The infection may be fatal if unrecognised. We report a case of C. septicum bacteremia in a man diagnosed with acute myeloid leukaemia.

Adult↗
PubMed1993

Fatal Chromobacterium violaceum septicaemia.

A 19-year-old Malay male succumbed to a septicaemia caused by Chromobacterium violaceum 11 days after onset of illness. The organism is a common soil saprophyte and may be considered as contaminant on culture. It is essential to recognise its clinical significance in purulent processes so that appropriate therapy can be instituted. We report the first fatal case of Chromobacterium violaceum infection in the University Hospital, Kuala Lumpur.

Abscess↗
PubMed1992

Identifying sites for catheter ablation of ventricular tachycardia.

The approach to localizing sites for catheter ablation of ventricular tachycardia foci depends on the type of tachycardia. In large reentry circuits such as those arising from infarct scars, areas of slow conduction in and around the scar should be targeted. During sinus rhythm, these can be suspected from the presence of fractionated electrograms and, at some sites, long stimulus to QRS delays during pacing. Slow conduction areas can be classified as: 1. central slow conduction zone sites, 2. exits from the slow conduction zone, 3. entrances to the slow conduction zone, and 4. bystander areas which are not involved in the tachycardia circuit. In the central slow conduction zone stimulation entrains or resets tachycardia with a long stimulus to QRS (S-QRS) delay (40 to greater than 300 ms) without altering the QRS morphology (entrainment with concealed fusion). At slow conduction zone exits, presystolic electrograms are recorded during VT, the pacemap matches the VT QRS morphology, and with pacing during VT the S-QRS interval is relatively short and VT may or may not be entrained. At entrances to the slow conduction zone electrogram timing is variable but early diastolic electrograms are expected and the pace-map QRS may differ from the VT QRS morphology. Relatively late stimuli or slow trains of stimuli entrain VT with concealed fusion with a relatively longer S-QRS interval than observed in the central slow conduction zone. Early stimuli may entrain VT while altering the QRS morphology due to propagation of the stimulated antidromic wavefront out of the scar from a site other than the tachycardia exit. At bystander sites electrogram timing, pace-mapping, and the effects of programmed stimulation are variable but may occasionally mimic reentry circuit sites. Relatively late stimuli are likely to capture the site without altering the VT. If discrete electrograms are present, analysis of these during pacing may provide further evidence that the site is not in the reentry circuit. Catheter ablation will probably be most effective at central slow conduction zone sites. When VT originates from a small focus surrounded by normal myocardium, such as is likely for idiopathic RV outflow tract and some idiopathic left ventricular tachycardias, presystolic electrical activity and pacemapping are likely to identify the tachycardia focus. For macroreentry involving the bundle branches, the right bundle branch can be easily targeted.

Animals↗
PubMed1991

Dissolution of intraocular fibrinous exudate by streptokinase.

In a prospective, open, pilot study, the authors evaluated the effects of intraocular injection of streptokinase on intraocular fibrin. The study was composed of nine patients in whom fibrinous exudate developed after pars plana vitrectomy. There were seven male and two female patients with a mean age of 44 years (range, 27 to 65 years). Fibrinous exudates were seen 1 to 22 days after surgery with obstruction of the view of the posterior segment. Each patient received a single intraocular injection of 1000 IU of purified streptokinase. Four hours after the streptokinase injection, complete dissolution of the fibrin was noted in each patient. There were no clinically detectable adverse effects from the intraocular administration of streptokinase. Streptokinase may be considered in the dissolution of intractable intraocular fibrinous exudates after vitrectomy.

Adult↗
PubMed1991

Detection of Clostridium difficile from an enhancement broth by gas-liquid chromatography.

Gas-Liquid chromatography (GLC) was used to detect the presence of isocaproic acid produced by Clostridium difficile from 54 stool samples grown in cycloserine-cefoxitin broth. Isocaproic acid was detected in 12 samples of which 5 were confirmed to be Clostridium difficile by culture and biochemical tests. The detection of isocaproic acid by GLC together with the presence of presumptive colonies on primary selective culture media provides a more rapid laboratory diagnosis for Clostridium difficile.

Caproates↗
PubMed1991

Some immunological aspects of chronic liver diseases in Egyptian children.

This study was conducted on 40 Egyptian children (21 males and 19 females) with various chronic liver diseases, selected from the out-patient Pediatric Hepatology Clinic of Ain Shams University Hospital. Their ages ranged from 1.5 to 13 years with a mean of 5.98 +/- 3.72 years. Twenty healthy children of comparable age and sex to the patients were chosen as controls. All children were subjected to detailed history taking, thorough clinical examination and laboratory investigations including full blood picture, urine and stool examination, liver function tests, prothrombin time and hepatitis B surface antigen in addition to sigmoidoscopy with rectal snip examination, abdominal ultrasonography and liver biopsy. Moreover, immunological investigations were done, that included estimation of the serum complement levels of C3 and C4 by using single radial immunodiffusion method, assessment of the phagocytic and intracellular killing activity of polymorphonuclear leucocytes by living Candida albicans uptake and detection of non organ specific autoantibodies in the serum by indirect immunofluorescence technique. This study showed that the serum level of C3 was increased and C4 was decreased significantly in patients with chronic liver disease, especially in chronic active hepatitis. Regarding phagocytosis, there was significant impairment of the neutrophil phagocytic function but not the intracellular lytic activity of candida albicans. This reduced phagocytic function was more pronounced in patients having chronic hepatitis and cirrhosis than in bilharzial and other cases. Serum autoantibodies; antinuclear and antimitochondrial antibodies were absent in the sera of both patients and controls, while antismooth muscle antibodies were found in the sera of 47.5% of patients with chronic liver diseases and non of the control sera. The highest incidence of these antibodies was present in HBs Ag negative patients with chronic active hepatitis (80%). We concluded that patients with chronic liver diseases have disturbed functions of both complement and phagocytic systems that may lead to increased susceptibility to recurrent infections. So, routine assessment of immunological status with early diagnosis and treatment of infections are important in the proper management of these patients. In addition, detection of serum auto-antibodies in these patients is helpful in the early diagnosis of auto-immune liver diseases.

Child↗
PubMed1991

Actions of three clostridial IgA proteases on distinct forms of immunoglobulin A molecules.

Three bacterial species of Clostridium (septicum, tertium and sporogenes) were identified to produce extracellular proteases cleaving IgA to Fab and Fc fragments, as demonstrated by SDS-PAGE and immunoelectrophoretic procedures. These enzymes acted on monometric IgA1 paraproteins and normal serum IgA1 but had no activity on IgA2 paraproteins and intact secretory IgA1 from human colostrum. Their action on polyclonal serum IgA1 suggested the absence of neutralizing anti-clostridial IgA protease activity. Although the enzymes were shown not to act on secretory IgA1, they were, however, able to digest free alpha-heavy chains of the dimeric IgA molecules. Susceptibility of the alpha-heavy chain to the proteases was more likely due to the change to a more accessible conformation than because of the absence of neutralizing anti-enzymic activity.

Clostridium↗
PubMed1990

[Comparative analysis in gastric cancer of total gastrectomy extended with lymphadenectomy and the other surgical technics. 10 years' experience].

Of 220 patients operated for gastric cancer, 74 with subtotal gastrectomy and 145 with total gastrectomy (60 with lymphadenectomy), the results and indications for total gastrectomy extended with lymphadenectomy are analysed. The importance of lymph node emptying in relation to the possibility of breakdown of the lymphnode chains with R2 metastasis is particularly stressed. Analysis of perioperative mortality and long-term survival indicates results that are close to the data reported by Japanese schools.

Adult↗