4-Amino-3-bromo-benzoic acid

The asymmetric unit of the title compound, C₇H₆BrNO₂, consists of two mol­ecules having a small variation of bond lengths and angles. The title compound forms dimers through pairs of O—H⋯O hydrogen bonds involving the carboxyl­ate groups. The dimers are linked into polymeric forms through inter­molecular hydrogen bonds, forming R₂¹(6), R₃²(8) and R₃³(15) ring motifs.

4-Chloro-1-iodo-2-nitro-benzene

In the mol­ecule of the title compound, C₆H₃ClINO₂, the nitro group is disordered over two sites with occupancies of 0.506 (6) and 0.494 (6). The dihedral angles between the benzene ring and the two disordered components of the nitro group are 29.0 (2) and 51.0 (3)°. The disordering avoids short O⋯O inter­molecular contacts in the crystal.

3,5-Dimethyl-2,6-diphenyl-3,4,5,6-tetra-hydro-2H-pyran-4-one

The mol­ecular structure of the title compound, C₁₉H₂₀O₂, reveals a slightly distorted chair conformation for the tetra­hydro­pyran ring with the two methyl and two phenyl substituents in equatorial positions.

3,3-Dichloro-1-ethyl-1H-2,1-benzothia-zin-4(3H)-one 2,2-dioxide

In the title compound, C₁₀H₉Cl₂NO₃S, the S atom, which is a component atom of a heterocyclic ring, shows tetra­hedral coordination. The heterocyclic ring is not planar.

6-Bromo-1-ethyl-1H-2,1-benzothia-zin-4(3H)-one 2,2-dioxide

In the title compound, C₁₀H₁₀BrNO₃S, the S atom is four-coordinated in a distorted tetra­hedral configuration with nearly equal S=O bond distances; the S—C and S—N bond lengths are 1.755 (3) and 1.649 (3) Å, respectively. The heterocyclic thia­zine ring adopts a twist conformation. Adjacent mol­ecules are attached to each other through inter­molecular C—H⋯O hydrogen bonds, forming R₂²(8) and R₂²(14) ring motifs. The mol­ecules are stabilized by intra- and inter­molecular hydrogen bonds, forming a three-dimensional polymeric network.

2-Chloro-5-(2-iodo-benzene-sulfonamido)-benzoic acid

In the mol-ecule of the title compound, C(13)H(9)ClINO(4)S, the coordination around the S atom is distorted tetra-hedral. The aromatic rings are oriented at a dihedral angle of 74.46 (9)°. Intra-molecular C-H⋯O hydrogen bonds result in the formation of two five- and one six-membered rings, which adopt planar, envelope and twisted conformations, respectively. In the crystal structure, inter-molecular N-H⋯O and O-H⋯O hydrogen bonds link the mol-ecules to form R(2) (2)(8) ring motifs, which are further linked by C-H⋯O hydrogen bonds. π-π contacts between the benzene rings [centroid-centroid distances = 3.709 (3) and 3.772 (3) Å] may further stabilize the structure. The I atom is disordered over two positions, refined with occupancies of ca 0.75 and 0.25.

4-(2-Iodo-benzene-sulfonamido)benzoic acid monohydrate

In the mol­ecule of the title compound, C₁₃H₁₀INO₄S·H₂O, the coordination around the S atom is distorted tetra­hedral. The aromatic rings are oriented at a dihedral angle of 74.18 (17)°. Intra­molecular C—H⋯O hydrogen bonds result in the formation of non-planar five- and six-membered rings, which adopt envelope and twist conformations, respectively. In the crystal structure, inter­molecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules. π–π Contacts between the phenyl rings [centroid–centroid distance = 3.726 (3) Å] may further stabilize the structure. There is also a C—H⋯π inter­action.

Sodium 2-iodo-benzene-sulfonate monohydrate

In the title compound, Na⁺·C₆H₄IO₃S⁻·H₂O, the Na atom is hexa­coordinated by O atoms, forming a two-dimensional sheet-like structure in the bc plane, with the iodo­benzene rings protruding above and below. Na⋯O contact distances are in the range 2.419 (2)–2.7218 (18) Å and O⋯Na⋯O angles are in the range 73.70 (5)–158.64 (7)°. The crystal structure is stabilized by O—H⋯O and C—H⋯O hydrogen bonds and C—H⋯π inter­actions. The I atom is disordered over two positions with occupancies of 0.78 (2) and 0.22 (2).

Methyl (4-bromo-benzene-sulfonamido)acetate

The title compound, C₉H₁₀BrNO₄S, is an inter­mediate for the formation of benzothia­zines. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules, forming R₂²(10) ring motifs, which are linked into a two-dimensional polymeric sheet through inter­molecular C—H⋯O hydrogen bonds.

(Cyano-meth-yl)triphenyl-phospho-nium chloride

In the mol­ecule of the title compound, C₂₀H₁₇NP⁺·Cl⁻, the coordination around the P atom is slightly distorted tetra­hedral. In the crystal structure, inter­molecular C—H⋯N and C—H⋯Cl hydrogen bonds link the mol­ecules. There is a π–π contact between the phenyl rings [centroid–centroid distance = 3.702 (3) Å].

Methyl 3-hydr-oxy-4-oxo-3,4-dihydro-2H-1,2-benzothia-zine-3-carboxyl-ate 1,1-dioxide monohydrate

In the mol-ecule of the title compound, C(10)H(9)NO(6)S·H(2)O, the benzothia-zine ring adopts an envelope conformation. An intra-molecular N-H⋯O hydrogen bond results in the formation of a nonplanar five-membered ring which has a twisted conformation. In the crystal structure, inter-molecular N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules to form a three-dimensional network. There is a π-π contact between the benzene rings [centroid-centroid distance = 3.972 (2) Å].

Potassium 2-iodo-benzene-sulfonate monohydrate

In the crystal structure of the title compound, K(+)·C(6)H(4)IO(3)S(-)·H(2)O, the potasium cation is 2.693 (3)-2.933 (3) Å from the sulfonate and water O atoms (including symmetry-related atoms) and forms a two-dimensional sheet-like structure in the bc plane, with the iodo-benzene rings protruding above and below. The water mol-ecule of crystallization is hydrogen-bonded to sulfonate O atoms within this two-dimensional arrangement. Symmetry-related iodo-benzene rings are arranged perpendicular to one another with the I atom ca 4.1 Å from the centroid of the neighbouring benzene ring. In the crystal structure, these two-dimensional sheet-like supramolecular structures are arranged parallel to one another, stacked along the a-axis direction, with the benzene rings inter-digitated.

3,3-Dibromo-1-ethyl-1H-2,1-benzo-thiazin-4(3H)-one 2,2-dioxide

In the mol-ecule of the title compound, C(10)H(9)Br(2)NO(3)S, the S atom is four-coordinated in distorted tetra-hedral configuration. The heterocyclic thia-zine ring adopts a twist conformation. An intra-molecular C-H⋯O hydrogen bond results in the formation of a non-planar five-membered ring. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into infinite chains along the c axis.

1-Methyl-1H-2,1-benzothia-zin-4(3H)-one 2,2-dioxide

In the crystal structure of the title compound, C₉H₉NO₃S, there is distorted tetra­hedral geometry around the S atom. The sulfonyl group is almost normal to the benzene ring, while the carbonyl O atom and methyl C atom are on opposite sides of this ring. The heterocyclic ring adopts a half-boat conformation with the S atom out of the plane. The mol­ecules are dimerized by hydrogen bonding involving the benzene ring and the sulfonyl group. These dimers are linked to each other in the same way. There is an intra­molecular hydrogen bond between a methyl C—H group and a sulfonyl O atom, and a π–π inter­action between the aromatic rings of two dimers at a centroid-to-centroid distance of 3.6373 (13) Å.

1-Ethyl-1H-2,1-benzothia-zin-4(3H)-one 2,2-dioxide

In the title compound, C₁₀H₁₁NO₃S, there is distorted tetra­hedral geometry around the S atom. The heterocyclic thia­zine ring adopts a half-chair conformation. The ethyl and sulfonyl groups form dihedral angles of 82.53 (13) and 88.91 (9)°, respectively, with the plane formed by the benzothia­zine ring, excluding the S atom; the S atom and the ethyl group lie on opposite sides of the ring. The mol­ecules are linked into dimers by inter­molecular C—H⋯O hydrogen bonds involving benzene C—H and carbonyl O atoms, thus forming eight-membered rings. The dimers are linked into chains via inter­actions of a similar type. There is an intra­molecular C—H⋯O hydrogen bond.

Methyl 2-(N-ethyl-methane-sulfonamido)benzoate

In the mol-ecule of the title compound, C(11)H(15)NO(4)S, the S atom environment is distorted tetrahedral. The methoxy-carbonyl group is oriented at a dihedral angle of 11.8 (2)° with respect to the benzene ring. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers.

Redox-mediated substrate recognition by Sdp1 defines a new group of tyrosine phosphatases

Reactive oxygen species trigger cellular responses by activation of stress-responsive mitogen-activated protein kinase (MAPK) signalling pathways. Reversal of MAPK activation requires the transcriptional induction of specialized cysteine-based phosphatases that mediate MAPK dephosphorylation. Paradoxically, oxidative stresses generally inactivate cysteine-based phosphatases by thiol modification and thus could lead to sustained or uncontrolled MAPK activation. Here we describe how the stress-inducible MAPK phosphatase, Sdp1, presents an unusual solution to this apparent paradox by acquiring enhanced catalytic activity under oxidative conditions. Structural and biochemical evidence reveals that Sdp1 employs an intramolecular disulphide bridge and an invariant histidine side chain to selectively recognize a tyrosine-phosphorylated MAPK substrate. Optimal activity critically requires the disulphide bridge, and thus, to the best of our knowledge, Sdp1 is the first example of a cysteine-dependent phosphatase that couples oxidative stress with substrate recognition. We show that Sdp1, and its paralogue Msg5, have similar properties and belong to a new group of phosphatases unique to yeast and fungal taxa.

Epilepsy: public knowledge and attitude in a slum area of Karachi, Pakistan

BACKGROUND

Epilepsy is a common but widely misunderstood illness. Consequently, epileptics suffer from considerable stigmatization in society. Since no studies have detailed the misperceptions about epilepsy in our community, it is not possible to provide focused intervention aimed at eliminating this prejudice.

PURPOSE

To assess the knowledge and attitude regarding epilepsy in an adult population of a Karachi slum area.

METHODS

A face-to-face interview was conducted on 487 consenting adult non-epileptics (305 males; 182 females) who were conveniently sampled. Chi-square test was employed to calculate the variability in knowledge and attitude with demographic and other variables.

RESULTS

In all, 12.5% had never heard about epilepsy. Among the rest, 66.7% identified epilepsy as being non-infectious, while 28.2% were unaware of any treatment available for it. Among the other 71.8%, 62.7% were aware of the existence of anti-epileptic drugs. Religious/spiritual treatment was chosen as the most effective treatment by 33.1%. Males were more likely to identify epilepsy as being non-infectious (p=0.02). Nearly 18% of the respondents would not object to their child marrying an epileptic, 69.5% did not want to socially isolate the epileptics, 83.1% said epileptics could receive academic education, 85.6% said they could perform activities of daily life and 62.4% said they could become useful members of the society. Those who considered epilepsy to be infectious were more likely to carry negative attitudes towards epilepsy (p<0.01 with four attitudes).

CONCLUSIONS

Considerable gaps exist in the community's knowledge about epilepsy. Some of these may explain the prevalence of negative attitudes towards this ailment.

Interactions and associations of paraoxonase gene cluster polymorphisms with myocardial infarction in a Pakistani population

Polymorphisms of paraoxonase gene (PON) cluster have been investigated in numerous studies for their association with myocardial infarction (MI) but the results have been conflicting. Epistasis and gene-environment interactions at this locus could possibly modulate susceptibility toward MI and account for the discrepancies. We carried out a case-control study (211 MI patients and 370 control subjects) to test association of PON cluster polymorphisms with MI, their interactions with each other and with smoking. Genotyping was performed by PCR-restriction fragment length polymorphism based assays. The Q192R, C-108T, and A148G polymorphisms were associated with MI. Two haplotypes consisting of C-108T, C311S, and A148G, having allele frequencies of 0.17 and 0.14 in the control population, predisposed to MI (global haplotype statistic chi2 = 34.74, df = 15, p = 0.0027). Multifactor dimensionality reduction analysis showed a significant three-locus model (p = 0.02) involving these three polymorphisms, suggesting a potential gene-gene interaction between PON1 and PON2. These polymorphisms also interacted with smoking, in a three-locus and a four-locus model (p = 0.01 and p = 0.05, respectively). Additionally, the R192 allele may advance the age-at-onset of MI. The PON cluster appears to be a susceptibility locus for MI in Pakistani population, and the susceptibility is modulated through gene-gene and gene-environment interactions.

Internal model control structure using adaptive inverse control strategy

In this paper, we propose a new adaptive internal model control scheme based on adaptive finite impulse response filters. This scheme provides the same design procedure for both minimum and nonminimum phase plants. The plants under consideration may contain time delay. The tracking objective is accomplished for both invertible and noninvertible stable plants. The internal model of the plant and its inverse are estimated by recursive least-squares and least-mean-squares algorithms, respectively. The closed loop is designed such that the system from the reference input to the plant output can be approximately represented by a pure delay. The effect of the process zeros on the output is compensated by using adaptive finite impulse response filters. This avoids the cancellation of noncancellable zeros of the plant and forces the plant output to track the reference input with a delay. The stability of the closed loop for both minimum and nonminimum phase systems is guaranteed. Computer simulation and laboratory scale experimental results are included in the paper to demonstrate the effectiveness of the proposed method.

Variability in lipid profile in patients with acute myocardial infarction from two tertiary care hospitals in Pakistan

OBJECTIVE

To investigate changes in total cholesterol, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol and triglycerides in serum of Pakistani patients with AMI due to age, gender, body mass index (BMI), diabetes, hypertension, and smoking, and also find out the prevalence of hypercholesterolemia, hypertriglyceridemia, "low HDL-cholesterol" and "isolated low-HDL cholesterol" in them.

PATIENTS AND METHODS

Serum samples from 451 consecutive AMI patients (250 from National Institute of Cardiovascular Diseases, Karachi and 201 from Armed Forces Institute of Cardiology, Rawalpindi) were analyzed for total cholesterol, HDL-cholesterol and triglycerides using kit methods. LDL-cholesterol was determined using the Friedewald formula.

RESULTS

Mean serum concentrations of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides in AMI patients were found to be 181 +/- 50 mg/dl, 35.7 +/- 11.3 mg/dl, 110 +/- 47 mg/dl and 177 +/- 127 mg/dl, respectively. Mean levels of total cholesterol and HDL-cholesterol were not significantly affected by age, gender, BMI, diabetes mellitus, hypertension and smoking. Mean LDL-cholesterol concentration, however, was found to be significantly increased in diabetes mellitus (p=0.047), while age, gender, BMI, hypertension and smoking had no significant effect on the levels of this lipoprotein. Mean levels of triglycerides were significantly decreased in older patients (>50 years) compared to younger (<50 years) ones (p=0.019). Gender, BMI, diabetes mellitus, hypertension and smoking, however, had no effect on triglyceride levels The frequencies of hypercholesterolemia, hypertriglyceridemia, "low HDL-cholesterol" and "isolated low-HDL-cholesterol" were found to be 30.6%, 30.1%, 48.6% and 34.1%, respectively.

CONCLUSION

High prevalence of hypertriglyceridemia and low HDL-cholesterol (which constitute a component of metabolic syndrome) in Pakistani AMI patients is suggestive that these two lipid abnormalities could be playing a major role in the development of atherosclerosis in Pakistani population.

Frontotemporal dementia: report of a familial case

The authors describe a 49-year-old woman (R.K.) who presented with one year of progressive frontal lobe dysfunction, including signs of expressive aphasia. Signs of parkinsonism were absent until late in the clinical course. Neuropsychologic testing and neuroimaging studies are described. The patient died at age 55, after 7 years of symptoms. Family history was remarkable for a mother who died at the age of 45, after experiencing 7 years of progressive aphasia. R.K.'s brain showed asymmetric frontotemporal atrophy, which was more severe on the left side. Histopathologic analysis was remarkable for numerous tau-positive neurons with some classic-appearing Pick bodies and many ballooned neurons. Tau-positive glial cells were also present. The authors suggest that the abnormal tau aggregates are related to the symptoms experienced by affected members of this family.