Spectrum of beta-thalassemia mutations in various regions of Punjab and Islamabad, Pakistan: establishment of prenatal diagnosis

We present here an analysis of 888 unrelated beta-thal chromosomes consisting of 444 transfusion dependent children from various regions of Punjab and Islamabad Pakistan. By using Multiplex ARMS- PCR, restriction endonuclease analysis, allele specific oligonucleotide (ASO) hybridization and sequencing, 17 beta-thal mutations and 3 Hb variants were detected in 99.5 % (884/888) of the chromosomes analyzed. First trimester prenatal diagnosis by chorionic villus sampling (CVS) was also carried out in seven pregnancies at risk of beta-thalassemia. Our results indicate that three most common mutations accounted for 86.8% of the beta-thal alleles in this region. These findings have important implications for prevention of beta-thalassemia through genetic counseling and prenatal diagnosis in this part of Pakistan.     

Performance of serum adenosine deaminase in measuring disease activity in rheumatoid arthritis patients

Background

Numerous tools to assess activity of rheumatoid arthritis (RA) are available to use. For any marker to be a more appropriate indicator of disease activity, it should be more authentic to the patho-physiologic basis of the disease.

Review of the use of cephalosporins in children with anaphylactic reactions from penicillins

OBJECTIVE:

It is a widely accepted practice that children with anaphylaxis from penicillins should avoid cephalosporins. The purpose of the present study was to determine whether there is evidence in the literature to support this practice.

DATA SOURCES:

MEDLINE, EMBASE, Toxline, International Pharmaceutical Abstracts and PubMed were used to search the literature published from 1966 to 2001. The Canadian Medical Protective Association, Health Canada and the Boston Collaborative Drug Surveillance Program were also contacted to determine whether there were any unpublished cases of cross-reactivity between penicillins and cephalosporins.

DATA EXTRACTION:

Cases describing the use of cephalosporins in adults and children with positive penicillin skin tests or anaphylaxis from penicillin were evaluated. Case reports of anaphylaxis from cephalosporins in paediatric patients were identified.

DATA SYNTHESIS:

There have been five reported cases of serious reactions from cephalosporins in patients with a history of anaphylaxis from penicillins. All cases occurred in adults; three developed anaphylaxis from the older, first-generation cephalosporins, cephalothin and cephaloridine; one developed anaphylaxis from cefamandole; and one developed anaphylaxis from cefaclor. There have been 12 other published reports of anaphylaxis from cephalosporins in adults with a history of penicillin allergy or a positive penicillin skin test, but with no history of anaphylaxis from penicillin. In seven studies, in which a total of 158 patients with positive penicillin skin tests were administered cephalosporins, seven had apparent immunoglobulin E-mediated reactions when they were given a cephalosporin. When the class of cephalosporin was able to be determined, none of the reports of reactions from cephalosporins in patients with allergies to penicillin involved third-generation cephalosporins. There have been 13 case reports of anaphylaxis from cephalosporins in paediatric patients.

CONCLUSION:

There are no published case reports of anaphylaxis from cephalosporins in children with anaphylaxis from penicillin, and there are only a small number of such reports in adults. Anaphylaxis from cephalosporins appears to be incredibly rare in children. There is minimal evidence in the literature to support the avoidance of cephalosporins in children with anaphylaxis from penicillins.Key Words: Anaphylaxis, Antibiotic allergy, Antibiotic hypersensitivity, Cephalosporins, Cross-reactivity, Drug allergy, Drug hypersensitivity, PenicillinA common problem in paediatrics is determining whether a cephalosporin can be used in a child with a history of a serious reaction from a penicillin, and whether a penicillin can be administered to a child with a history of a serious reaction from a cephalosporin. In many cases, such patients are prescribed antibiotics that are less effective, more toxic, have a broader spectrum or are more expensive than the drug of choice for their condition.Diagnostic tests for antibiotic allergies are limited and are standardized only for penicillin.When penicillin is metabolized, the beta-lactam ring opens to form a penicilloyl derivative that, when bound to serum and tissue proteins, accounts for more than 90% of immunologically active penicillin metabolites (the major determinants). However, about 16% of allergic reactions to penicillin involve multiple, different antigens that result from further penicillin metabolism. These antigens are referred to as minor determinants (1). In patients who have a history of penicillin allergy but negative skin test results using major and minor determinants, studies have shown that the chance of a serious allergic reaction to penicillin is negligible (1). Skin testing for cephalosporin allergy is sometimes performed, but is not standardized because the antigenic determinants of a serious allergic reaction have not been established. Standard teaching is that patients who have had possible anaphylaxis from penicillin should be given cephalosporins only with extreme caution, because their risk of developing anaphylaxis from cephalosporins is increased (2). Penicillins have a beta-lactam ring attached to a thialazolidine ring with one side chain, while cephalosporins have a beta-lactam ring attached to a dihydrothiazine ring with two side chains (1) (Figure ​(Figure1).1). Because of the similar structures, there is a theoretical risk of cross-reactivity between penicillins and cephalosporins.Open in a separate windowFigure 1Comparison of chemical structure of penicillins and cephalosporins. R Side chainSoon after cephalosporins were introduced, there were reports of anaphylaxis in patients who were given cephalosporins and who had also experienced anaphylaxis from penicillin. Furthermore, during the initial clinical trials with first-generation cephalosporins and cefamandole, 8.1% of patients with a history of allergy to a penicillin had a possible allergy to a cephalosporin, compared with 4.5% of patients with no such history (3). However, in those initial trials, no attempt was made to ensure that the reaction to the penicillin or to the cephalosporin was truly allergic. The purpose of the present study was to determine whether there is further evidence in the literature to support the avoidance of cephalosporins in children with suspected penicillin allergies. If the risk of cross-reactivity between penicillins and cephalosporins is low in the adult population, the same is probably true for the paediatric population. Therefore, the incidence of case reports of anaphylaxis from cephalosporins in adults or children with anaphylaxis from penicillin or a positive penicillin skin test was studied. The results of cephalosporin challenge in patients with positive penicillin skin tests were also reviewed. If it is exceedingly rare for children to develop anaphylaxis from cephalosporins, it may not be necessary to avoid their use in children who are allergic to penicillins. Therefore, the total number of published case reports of anaphylaxis from cephalosporins in all children was also researched.     

Remission rate after transsphenoidal surgery in patients with pathologically confirmed Cushing’s disease, the role of cortisol, ACTH assessment and immediate reoperation: a large single center experience

Postoperative serum cortisol is used as an indicator of Cushing’s disease (CD) remission following transsphenoidal surgery (TSS) and guides (controversially) the need for immediate adjuvant treatment for CD. We investigated postoperative cortisol and adrenocorticotropic hormone (ACTH) levels as predictors of remission/recurrence in CD in a large retrospective cohort of patients with pathologically confirmed CD, over 6 years at a single institution. Midnight and morning cortisol, and ACTH at 24–48 h postoperatively (>24 h after last hydrocortisone dose) were measured. Remission was defined as normal 24-h urine free cortisol, normal midnight salivary cortisol, a normal dexamethasone-corticotropin releasing hormone (CRH) test or continued need for hydrocortisone, assessed periodically. Statistical analysis was performed using PASW 18. Follow up data was available for 52 patients (38 females and 14 males), median follow up was 16.5 month (range 2–143 months), median age was 45 years (range 21–72 years), 28 tumors were microadenomas and 16 were macroadenomas, and in eight cases no tumor was observed on magnetic resonance imaging. No patient with postoperative cortisol levels >10 mcg/dl were found to be in remission. Ten of the 52 patients with cortisol >10 mcg/dl by postoperative day 1–2 underwent a second TSS within 7 days. Forty-three patients (82.7 %) achieved CD remission (36 after one TSS and 7 after a second early TSS) and six patients suffered disease recurrence (mean 39.2 ± 52.4 months). An immediate second TSS induced additional hormonal deficiencies (diabetes insipidus) in three patients with no surgical complications. Persistent disease was noted in nine patients despite three patients having an immediate second TSS. Positive predictive value for remission of cortisol <2 mcg/dl and ACTH <5 pg/ml was 100 %. Cortisol and ACTH levels (at all postoperative time points and at 2 months) were correlated (r = 0.37, P < 0.001). Nadir serum cortisol of ≤2 mcg/dl and ACTH <5 pg/ml predicted remission (P < 0.005), but no level predicted lack of recurrence. Immediate postoperative ACTH/cortisol did not predict length of remission. No patients with postoperative cortisol >10 mcg/dl were observed to have delayed remission; all required additional treatment. There was no significant difference in age, body mass index, tumor size and length of follow-up between postoperative cortisol groups: cortisol ≤2 mcg/dl, cortisol >5 mcg/dl and cortisol >10 mcg/dl. Immediate postoperative cortisol levels should routinely be obtained in CD patients post TSS, until better tools to identify early remission are available. Immediate repeat TSS could be beneficial in patients with cortisol >10 mcg/dl and positive CD pathology: our combined (micro- and macroadenomas) remission rate with this approach was 82.7 %. ACTH measurements correlate well with cortisol. However, because no single cortisol or ACTH cutoff value excludes all recurrences, patients require long-term clinical and biochemical follow-up. Further research is needed in this area.     

Prevalence of gastric varices and results of sclerotherapy with N-butyl 2 cyanoacrylate for controlling acute gastric variceal bleeding

AIM: To study the prevalence, predictors and control of bleeding following N-butyl 2 cyanoacrylate (NBC) sclerotherapy of gastric varix (GV). METHODS: We analyzed case records of 1436 patients with portal hypertension, who underwent endoscopy during the past five years for variceal screening or upper gastrointestinal (GI) bleeding. Fifty patients with bleeding GV underwent sclerotherapy with a mean of 2 mL NBC for control of bleeding. Outcome parameters were primary hemostasis (bleeding control within the first 48 h), recurrent bleeding (after 48 h of esophago- gastro-duodenoscopy) and in-hospital mortality were analyzed. RESULTS: The prevalence of GV in patients with portal hypertension was 15% (220/1436) and the incidence of bleeding was 22.7% (50/220). Out of the 50 bleeding GV patients, isolated gastric varices (IGV-I) were seen in 22 (44%), gastro-oesophageal varices (GOV) on lesser curvature (GOV-Ⅰ) in 16 (32%), and GOV on greater curvature (GOV-Ⅱ) in 15 (30%). IGV-Ⅰ was seen in 44% (22/50) patients who had bleeding as compared to 23% (39/170) who did not have bleeding (P < 0.003). Primary hemostasis was achieved with NBC in all patients. Re-bleeding occurred in 7 (14%) patients after 48 h of initial sclerotherapy. Secondary hemostasis was achieved with repeat NBC sclerotherapy in 4/7 (57%). Three patients died after repeat sclerotherapy, one during transjugular intrahepatic portosystemic stem shunt (TIPSS), one during surgery and one due to uncontrolled bleeding. Treatment failure-related mortality rate was 6% (3/50). CONCLUSION: GV can be seen in 15% of patients withportal hypertension and the incidence of bleeding is 22.7%. NBC is highly effective in controlling GV bleeding. In hospital mortality of patients with bleeding GV is 6%.     

A systematic review and meta-analysis of cold in situ perfusion and preservation for pancreas transplantation

Background

This study aimed to identify the most effective solution for in situ perfusion/preservation of the pancreas in donation after brain death donors, in addition to optimal in situ flush volume(s) and route(s) during pancreas procurement.

Aβ neurotoxicity depends on interactions between copper ions, prion protein, and N-methyl-D-aspartate receptors

N-methyl-d-aspartate receptors (NMDARs) mediate critical CNS functions, whereas excessive activity contributes to neuronal damage. At physiological glycine concentrations, NMDAR currents recorded from cultured rodent hippocampal neurons exhibited strong desensitization in the continued presence of NMDA, thus protecting neurons from calcium overload. Reducing copper availability by specific chelators (bathocuproine disulfonate, cuprizone) induced nondesensitizing NMDAR currents even at physiologically low glycine concentrations. This effect was mimicked by, and was not additive with, genetic ablation of cellular prion protein (PrP(C)), a key copper-binding protein in the CNS. Acute ablation of PrP(C) by enzymatically cleaving its cell-surface GPI anchor yielded similar effects. Biochemical studies and electrophysiological measurements revealed that PrP(C) interacts with the NMDAR complex in a copper-dependent manner to allosterically reduce glycine affinity for the receptor. Synthetic human Aβ(1-42) (10 nM-5 μM) produced an identical effect that could be mitigated by addition of excess copper ions or NMDAR blockers. Taken together, Aβ(1-42), copper chelators, or PrP(C) inactivation all enhance the activity of glycine at the NMDAR, giving rise to pathologically large nondesensitizing steady-state NMDAR currents and neurotoxicity. We propose a physiological role for PrP(C), one that limits excessive NMDAR activity that might otherwise promote neuronal damage. In addition, we provide a unifying molecular mechanism whereby toxic species of Aβ(1-42) might mediate neuronal and synaptic injury, at least in part, by disrupting the normal copper-mediated, PrP(C)-dependent inhibition of excessive activity of this highly calcium-permeable glutamate receptor.     

A comparison of the presence of Theileria ovis by PCR amplification of their SSU rRNA gene in small ruminants from two provinces of Pakistan

ObjectiveTo compare the presence of Theileria ovis in small ruminants from two provinces of Pakistan and to determine the risk factors associated with the spread of theileriosis.MethodsIn present study, a total of 210 blood samples were collected from sheep (n=99) and goats (n=111) from 5 sampling sites in Punjab (Dera Ghazi Khan, Layyah, Multan and Rahim Yar Khan districts) and Khyber Pukhtoon Khwa (district Kohat) provinces, in Pakistan, from randomly selected herds. Data on the characteristics of the animals (species, gender, age, tick presence or absence, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) was collected through questionnaires.ResultsTwelve blood samples (6% of total), 11 from district Kohat, produced the 520 base pairs DNA fragment specific for small subunit ribosomal RNA (ssu rRNA) gene of Theileria ovis, by PCR amplification, of which 11 were sheep and 1 was goat indicating that sheep are more significantly (P=0.001) prone to this parasite. On the other hand parasite was detected only in 2 out of 210 samples (1%) by blood smear screening confirming PCR as the reliable detection tool.ConclusionsPCR is more sensitive and reliable diagnostic tool for detection of Theileria sp. as compared to blood smear screening. Incidence of Theileria ovis is very high in Khyber Pukhtoon Khwa as compared to Punjab province. It was also observed that presence of ticks on animals was the only significant risk factor associated with the theileriosis in small ruminants.     

From the Cover: Ecosystem responses in the southern Caribbean Sea to global climate change

Over the last few decades, rising greenhouse gas emissions have promoted poleward expansion of the large-scale atmospheric Hadley circulation that dominates the Tropics, thereby affecting behavior of the Intertropical Convergence Zone (ITCZ) and North Atlantic Oscillation (NAO). Expression of these changes in tropical marine ecosystems is poorly understood because of sparse observational datasets. We link contemporary ecological changes in the southern Caribbean Sea to global climate change indices. Monthly observations from the CARIACO Ocean Time-Series between 1996 and 2010 document significant decadal scale trends, including a net sea surface temperature (SST) rise of ∼1.0 ± 0.14 °C (±SE), intensified stratification, reduced delivery of upwelled nutrients to surface waters, and diminished phytoplankton bloom intensities evident as overall declines in chlorophyll a concentrations (ΔChla = −2.8 ± 0.5%⋅y⁻¹) and net primary production (ΔNPP = −1.5 ± 0.3%⋅y⁻¹). Additionally, phytoplankton taxon dominance shifted from diatoms, dinoflagellates, and coccolithophorids to smaller taxa after 2004, whereas mesozooplankton biomass increased and commercial landings of planktivorous sardines collapsed. Collectively, our results reveal an ecological state change in this planktonic system. The weakening trend in Trade Winds (−1.9 ± 0.3%⋅y⁻¹) and dependent local variables are largely explained by trends in two climatic indices, namely the northward migration of the Azores High pressure center (descending branch of Hadley cell) by 1.12 ± 0.42°N latitude and the northeasterly progression of the ITCZ Atlantic centroid (ascending branch of Hadley cell), the March position of which shifted by about 800 km between 1996 and 2009.