Efficacy of Citrullus colocynthis seed extract on Earias vittella, Fabricius, (Lepidoptera: Noctuidae): environment sustainable approach

Abstract Earias vittellaFabricius, 1794 (Noctuidae: Lepidoptera) is deliberated to be one of the most destructive pests of cotton and okra vegetation in the world including Asia. The pest has established resistance to various synthetic insecticides. The use of bio-pesticide is one of the unconventional approaches to develop a vigorous ecosystem without harming non- target pests and beneficial natural insect fauna. In the present study, the toxicity levels of Citrullus colocynthis seed extract have been evaluated against the populations of E. vittellaunder standardized laboratory conditions. The toxic effects of C. colocynthis on development periods, protein contents and esterase activity of the life stages of E. vittella were also evaluated. The toxicity levels of methanol, ethanol, hexane, water and profenofos were evaluated on the 1st instar larvae of E. vittella. LC30 and LC80 concentrations exhibited the effectiveness of methanol-based C. colocynthis seed extract against 1st instar larvae of E. vitella. The enhanced larval and pupal periods were revealed in treated samples during the comparison with untreated samples. The intrinsic rate of increase, net reproductive rate in the LC30 and LC80 concentrations exposed larvae remained less than the control treatment. Fecundity, the esterase activity and protein contents were declined in LC30 and LC80 treated samples as compared to the control. The present findings suggest that C. colosynthis extracts based botanical insecticides are beneficial, ecosystem sustainable and can be integrated with insect management programs from environment safety perspective.

Architectural and biochemical changes in embryonic tissues of maize under cadmium toxicity

Heavy metals greatly alter plant morphology and architecture, however detailed mechanisms of such changes are not fully explored. Two experiments were conducted to investigate the influence of cadmium (CdCl2 · 2.5H2 O) on some germination, morphological, biochemical and histological characteristics of developing embryonic tissue of maize. In the first experiment, maize seeds were germinated in increasing levels of CdCl2 (200-2000 μm) in sand and measurements were taken of changes in germination and seedling development attributes. Based on these parameters, 1000 μM CdCl2 was chosen for detailed biochemical and histological measurements. In the second experiment, seeds were germinated in Petri dishes and supplied with 0 (control) or 1000 μM CdCl2 (Cd-treated). Radicle, plumule, coleoptile and coleorhiza were measured for biochemical and histological changes. The highest amount of Cd was in the coleorhiza and radicle. Free proline, soluble sugars, anthocyanin, soluble phenolics, ascorbic acid, H2 O2 and MDA were significantly higher in coleorhizae, followed by the coleoptile, radicle and plumule. Although the radicle and coleorhiza were relatively poor targets of Cd than the other tissues, Cd stress reduced cortical cell size and vascular tissues, and deformed xylem and phloem parenchyma in all plant parts. In conclusion, the main reason for reduced germination was the influence of Cd on architecture of the coleorhiza and coleoptile, which was the result of oxidative stress and other physiological changes taking place in these tissues.

A Novel ABCA12 Mutation in Two Families with Congenital Ichthyosis

Autosomal recessive congenital ichthyosis (ARCI) is a rare genetically heterogeneous disorder characterized by hyperkeratosis in addition to dry, scaly skin. There are six genes currently known to be associated with the disease. Exome sequencing data for two affected individuals with ichthyosis from two apparently unrelated consanguineous Pakistani families was analysed. Potential candidate mutations were analysed in additional family members to determine if the putative mutation segregated with disease status. A novel mutation (c.G4676T, p.Gly1559Val) in ABCA12 occurred at a highly conserved residue, segregated with disease status in both families, and was not detected in 143 control chromosomes. Genotyping with microsatellite markers demonstrated a partial common haplotype in the two families, and a common founder mutation could not be excluded. Comparison to previously reported cases was consistent with the hypothesis that severe loss of function ABCA12 mutations are associated with Harlequin Ichthyosis and missense mutations are preferentially associated with milder phenotypes. In addition to identifying a possible founder mutation, this paper illustrates how advances in genome sequencing technologies could be utilised to rapidly elucidate the molecular basis of inherited skin diseases which can be caused by mutations in multiple disease genes.

Long-term tryptophan administration enhances cognitive performance and increases 5HT metabolism in the hippocampus of female rats

It has been shown in various studies that increase in serotonergic neurotransmission is associated with increased memory consolidation whereas low brain 5HT impairs memory performance. In the first phase of our study we found that tryptophan (TRP) administration for 6 weeks increased plasma TRP and whole brain TRP, 5HT and 5HIAA levels. Many brain regions are involved in the learning process but particularly the hippocampus is known to have key role in learning and memory. The present study was therefore designed to investigate the effects of TRP loading particularly on hippocampal 5HT metabolism and cognitive performance in rats. TRP-treated rats demonstrated spatial enhancement as evidenced by a significant decrease in time to find the hidden food reward in radial arm maze test (RAM). The important finding of the present study was the greater increase in the 5HT metabolism in hippocampus than in any other brain region of the TRP-treated rats. This increased 5HT metabolism in the hippocampus emphasizes the involvement of this region in memory process.

Identification of novel mutations in the SEMA4A gene associated with retinal degenerative diseases

Semaphorins are a large family of transmembrane proteins. The gene for SEMA4A encodes a transmembrane protein comprising 760 amino acids. To investigate its association with human retinal degeneration, mutation screening of the SEMA4A gene was carried out on 190 unrelated patients suffering from a variety of eye diseases. We report the first observation of the involvement of SEMA4A gene mutations causing retinitis pigmentosa (RP) and cone rod dystrophy (CRD). We screened the DNA of 135 patients with RP, 25 patients with CRD, and 30 with LCA using SSCP and direct DNA sequencing for mutations in the SEMA4A gene. Two mutations, p.D345H and p.F350C, were observed only in affected patients; they were not observed in any of the normal members or the 100 control subjects. Both mutations identified occur in the conserved semaphorin domain. Multiple sequence alignments using Clustal analysis showed that R713Q is a conserved substitution and D345H is a semi-conserved substitution. We conclude that these mutations are a cause of various retinal degenerations.

Frequency of CCR5 Gene 32-bp deletion in Pakistani ethnic groups

CCR5 is a G-protein-coupled chemokine receptor that is used as a co-factor by macrophage-tropic (M-tropic) isolates of human immunodeficiency virus-1 (HIV-1) to gain entry into host cells. A 32-bp deletion in the CCR5 gene (CCR5-Delta32) leads to the production of an altered gene product that prevents HIV-1 from entering the host cell. This study was carried out to determine prevalence of CCR5-Delta32 allele frequency in a large Pakistani population sample (n = 821) representing 10 ethnic groups. No individual was homozygous for the mutant allele and the frequency of the CCR5-Delta32 allele ranged from 0.62% to 3.57%. The CCR5-Delta32 allele frequency was generally lower in populations from southern Pakistan. The overall frequency of the CCR5-Delta32 allele in Pakistan was 2.31%, which is much lower than that found in European populations and similar to that in the Middle East. This is consistent with the historical records and genetic data that indicate a close genetic affinity among these populations. This study demonstrates that the Pakistani population is highly susceptible to M-tropic isolates of HIV-1 and public health measures need to be enforced with urgency if Pakistan is to avoid an HIV epidemic.

HLA polymorphism in six ethnic groups from Pakistan

The extreme polymorphism found at some of the loci of the HLA system has made it an invaluable tool for population genetic analyses. In this study the genetic polymorphism of six Pakistani ethnic groups was investigated at the HLA-A, -B, -C, -DRB and DQB1 loci using polymerase chain reaction with sequence specific primers. The groups included in this study are the Baloch, Brahui and Sindhi from the south and the Burusho, Kalash and Pathan from the north of Pakistan. The allele frequencies, three-locus haplotype frequencies for HLA-A, -C, -B and HLA-A, -B, -DRB1 are given. Variation in the allele and haplotype distribution between the six Pakistani ethnic groups was observed. A phylogenetic tree and correspondence analysis based on HLA-A, -B, -C, -DRB1 and -DQB1 allele frequencies revealed the Kalash population to be distinct from the remaining Pakistani populations. The Baloch and Brahui were closely related to one another. The Sindhi were closer to the Pathan and Burusho populations than to the neighboring Baloch and Brahui populations, indicating admixture between the northern and southern populations of Pakistan. A phylogenetic tree and correspondence analysis comparing the Pakistani populations with various other world populations showed that the Pakistani ethnic groups lie within the cluster of Asian Indian populations. The three-locus haplotypes found in the Pakistani populations suggest an influence from Caucasian and Oriental populations.

Locus for autosomal recessive nonsyndromic persistent hyperplastic primary vitreous

PURPOSE

To map the disease locus in a six-generation, consanguineous Pakistani family affected by nonsyndromic autosomal recessive persistent hyperplastic primary vitreous (arPHPV). All affected individuals had peripheral anterior synechiae and corneal opacities with variable degrees of cataract and a retrolenticular white mass behind the lens.

METHODS

Genomic DNA from family members was typed for alleles at more than 400 known polymorphic genetic markers, by polymerase chain reaction. Alleles were assigned to individuals, which allowed calculation of lod scores.

RESULTS

A maximum two-point lod score of 4.07 was obtained with marker D10S1225 with no recombination. Two recombinations with marker D10S208 and D10S537 localized the disease within a region of approximately 30 centimorgans (cM). However, homozygosity across the region refined the arPHPV locus to 13 cM.

CONCLUSIONS

Linkage analysis shows localization of nonsyndromic arPHPV to chromosome10q11-q21.

Fiber-optic liquid-level sensor using a long-period grating

A liquid-level sensor based on the refractive-index sensitivity of long-period fiber-optic gratings is proposed and demonstrated. The form of the transmission spectrum of the long-period grating is dependent on the fraction of the length of the long-period grating that is surrounded by the liquid. The sensor shows a large linear range, with sensitivity of 4.8% change in transmission per millimeter, for a long-period grating with a length of 40 mm and a periodicity of 400mu;m .

A new locus for autosomal recessive RP (RP29) mapping to chromosome 4q32-q34 in a Pakistani family

PURPOSE

To map the disease locus in a six-generation, consanguineous Pakistani family with autosomal recessive retinitis pigmentosa (arRP). All affected individuals had pigmentary retinopathy associated with symptoms of night blindness and the loss of peripheral visual fields by the age of 20 years, loss of central vision between the ages of 25 and 30 years, and complete blindness between the ages of 40 and 50 years.

METHODS

Genomic DNA from family members was typed for alleles at known polymorphic genetic markers using polymerase chain reaction. Alleles were assigned to individuals, which allowed calculation of LOD scores using the programs Cyrillic (http://www.cyrillicsoftware.com) and MLINK (Cherwell Scientific Publishing LTD:, Oxford, UK). The genes for membrane glycoprotein (M6a) and chloride channel 3 (CLCN3) were analyzed by direct sequencing for mutations.

RESULTS

A new locus for arRP (RP29) has been mapped to chromosome 4q32-q34. A maximum two-point LOD score of 3.76 was obtained for the marker D4S415, with no recombination. Two recombination events in the pedigree positioned this locus to a region flanked by markers D4S621 and D4S2417. A putative region of homozygosity by descent was observed between the loci D4S3035 and D4S2417, giving a probable disease interval of 4.6 cM. Mutation screening of two candidate genes, M6a and CLCN3, revealed no disease-associated mutations.

CONCLUSIONS

The results suggest that the arRP phenotype maps to a new locus and is due to a mutated gene within the 4q32-q34 chromosomal region.

RP1 protein truncating mutations predominate at the RP1 adRP locus

PURPOSE

Recent reports have shown that the autosomal dominant retinitis pigmentosa (adRP) phenotype linked to the pericentric region of chromosome 8 is associated with mutations in a gene designated RP1. Screening of the whole gene in a large cohort of patients has not been undertaken to date. To assess the involvement and character of RP1 mutations in adRP, the gene was screened in a panel of 266 unrelated patients of British origin and a Pakistani family linked to this locus.

METHODS

Patients exhibiting the adRP phenotype were screened for mutations in the four exons of the RP1 gene by heteroduplex analysis and direct sequencing. Linkage of the Pakistani family was achieved using microsatellite markers. Polymerase chain reaction (PCR) products were separated by nondenaturing polyacrylamide gel electrophoresis. Alleles were assigned to individuals, which allowed calculation of LOD scores. Microsatellite marker haplotyping was used to determine ancestry of patients carrying the same mutation.

RESULTS

In the 266 British patients and 1 Pakistani family analyzed, 21 loss-of-function mutations and 7 amino acid substitutions were identified, some of which may also be disease-causing. The mutations, many of which were deletion or insertion events, were clustered in the 5' end of exon 4. Most mutations resulted in a premature termination codon in the mRNA. Haplotype analysis of nine patients carrying an R677X mutation suggested that these patients are not ancestrally related.

CONCLUSIONS

RP1 mutations account for 8% to 10% of the mutations in our cohort of British patients. The most common disease-causing mechanism is deduced to be one involving the presence of a truncated protein. Mutations in RP1 have now been described in adRP patients of four ethnically diverse populations. The different disease haplotype seen in the nine patients carrying the same mutation suggests that this mutation has arisen independently many times, possibly due to a mutation hot spot in this part of the gene.

Novel locus for autosomal recessive cone-rod dystrophy CORD8 mapping to chromosome 1q12-Q24

PURPOSE

To map the disease locus of a two-generation, consanguineous Pakistani family with autosomal recessive cone-rod dystrophy (arCRD). All affected individuals had night blindness, deterioration of central vision, photophobia, epiphora in bright light, and problems with color distinction. Fundoscopy revealed marked macular degeneration and attenuation of retinal vessels. Mild pigmentary changes were present in the periphery.

METHODS

Genomic DNA was amplified across the polymorphic microsatellite poly-CA regions identified by markers. Alleles were assigned to individuals that allowed calculation of LOD scores using the Cyrillic (Cherwell Scientific, Oxford, UK) and MLINK (accessed from ftp://linkage. rockefeller.edu/softeware/linkage/) software programs. The cellular retinoic acid-binding protein 2 (CRABP2), cone transducin alpha-subunit (GNAT2), potassium inwardly rectifying channel, subfamily J, member 10 (KCNJ10), genes were analyzed by heteroduplex analysis and direct sequencing for mutations.

RESULTS

A new locus for arCRD (CORD8) has been mapped to chromosome 1q12-q24. A maximum two-point LOD score of 4.22 was obtained with marker D1S2635 at recombination fraction of theta = 0.00. Two critical recombinations in the pedigree positioned this locus to a region flanked by markers D1S457 and D1S2681. A region of homozygosity was observed within the loci D1S442 and D1S2681, giving a probable critical disease interval of 21 cM. Mutation screening of the three candidate genes CRABP2, GNAT2, and KCNJ10 revealed no disease-associated mutations.

CONCLUSIONS

The findings therefore suggest that this phenotype maps to a new locus and is due to an as yet uncharacterized gene within the 1q12-q24 chromosomal region.

P53 mutations, polymorphisms, and haplotypes in Pakistani ethnic groups and breast cancer patients

Inactivation of the p53 gene has been found to be associated with the pathogenesis of several neoplasias. Three biallelic polymorphisms in the p53 gene have been linked to predisposition to the development of various malignancies. These include a 16-bp duplication in intron 3 and BstU I and Msp I restriction fragment length polymorphisms (RFLPs) in exon 4 and intron 6, respectively. The prevalence of these polymorphisms was studied in breast cancer patients and nine major ethnic groups of Pakistan. Differences in allele frequencies for all three polymorphisms were observed among the various ethnic groups and breast cancer patients. The absence of the 16-bp duplication was common among the northern ethnic groups, being highest in the Hazara (0.90). The Msp I A1 allele frequency in the southern Makrani population was significantly higher in comparison with the other ethnic groups. In the cancer patients, the absence of the 16-bp duplication in combination with the BstU I Pro and absence of Msp I restriction site were the most frequent. In these patients, ten substitution mutations were found in the p53 gene, seven of which have been reported previously for breast cancer. The remaining three mutations have been found in other malignancies, but not in carcinoma of the breast.

Severe autosomal dominant retinitis pigmentosa caused by a novel rhodopsin mutation (Ter349Glu). Mutations in brief no. 208. Online

Mutations in the rhodopsin gene are reported to be responsible for approximately 25% of all cases of autosomal dominant Retinitis pigmentosa (adRP). Affected individuals from a large family with an unusually severe form of adRP were screened for mutations in the rhodopsin gene. Direct sequencing of exon 5 revealed a TAA to GAA transversion at nucleotide 5276/codon 349, which was confirmed by Dde1 restriction digest analysis. This change would replace the normal termination codon with a glutamic acid residue (Ter-349-Glu, or X349E). The next predicted termination codon (TAA) lies 153bp downstream at nucleotides 5429 to 5431. Termination of transcription at this point would add an additional 51 amino-acid residues to the carboxy terminus of the rhodopsin molecule. This mutation is unique in producing a mutant rhodopsin in which all of the normal 348 amino-acid residues remain intact. It produces one of the most severe adRP phenotypes ever observed in a family with a rhodopsin mutation. In view of this the Ter-349-Glu mutation is worthy of further investigation to determine how the presence of this particular mutant opsin leads to rod photoreceptor degeneration.

Mutations in a new photoreceptor-pineal gene on 17p cause leber congenital amaurosis. Nat gen 2000;24:79-83

Leber congenital amaurosis (LCA, MIM 204000) accounts for at least 5% of all inherited retinal disease1 and is the most severe inherited retinopathy with the earliest age of onset2. Individuals affected with LCA are diagnosed at birth or in the first few months of life with severely impaired vision or blindness, nystagmus and an abnormal or flat electroretinogram (ERG). Mutations in GUCY2D (ref. 3), RPE65 (ref. 4) and CRX (ref. 5) are known to cause LCA, but one study identified disease-causing GUCY2D mutations in only 8 of 15 families whose LCA locus maps to 17p13.1 (ref. 3), suggesting another LCA locus might be located on 17p13.1. Confirming this prediction, the LCA in one Pakistani family mapped to 17p13.1, between D17S849 and D17S960—a region that excludes GUCY2D. The LCA in this family has been designated LCA4 (ref. 6). We describe here a new photoreceptor/pineal-expressed gene, AIPL1 (encoding arylhydrocarbon interacting protein-like 1), that maps within the LCA4 candidate region and whose protein contains three tetratricopeptide (TPR) motifs, consistent with nuclear transport or chaperone activity. A homozygous nonsense mutation at codon 278 is present in all affected members of the original LCA4 family. AIPL1 mutations may cause approximately 20% of recessive LCA, as disease-causing mutations were identified in 3 of 14 LCA families not tested previously for linkage.

A novel locus for Leber congenital amaurosis (LCA4) with anterior keratoconus mapping to chromosome 17p13

PURPOSE

A two-generation consanguineous Pakistani family with autosomal recessive Leber congenital amaurosis (LCA, MIM 204,000) and keratoconus was identified. All affected individuals have bilateral keratoconus and congenital pigmentary retinopathy. The goal of this study was to link the disease phenotype in this family.

METHODS

Genomic DNA was amplified across the polymorphic microsatellite poly-CA regions identified by markers. Polymerase chain reaction (PCR) products were separated by nondenaturing polyacrylamide gel electrophoresis. Alleles were assigned to individuals, which allowed calculation of LOD scores using the Cyrillic and MLINK software program. The retinal guanylate cyclase (RETGC-1, GDB symbol GUC2D) and pigment epithelium-derived factor (PEDF) genes were analyzed by heteroduplex analysis and direct sequencing for mutations in diseased individuals.

RESULTS

Based on a whole genome linkage analysis the first locus for this combined phenotype has been mapped to chromosome 17p13. Linkage analysis gave a two point LOD score of 3.21 for marker D17S829. Surrounding this marker is a region of homozygosity of 15.77 cM, between the markers D17S1866 and D17S960; however, the crossover for the marker D17S1529 refines the region to 10.77 cM within which the disease gene is predicted to lie. Mutation screening of the nearby RETGC-1 gene, which has been shown to be associated with LCA1, revealed no mutations in the affected individuals of this family. Similarly, another prime candidate in the region PEDF was also screened for mutations. The factor has been shown to be involved in the photoreceptor differentiation and neuronal survival. No mutations were found in this gene either. Furthermore, RETGC-1 was physically excluded from the critical disease region based on the existing physical map.

CONCLUSIONS

It is therefore suggested that this combined phenotype maps to a new locus and is due to an as yet uncharacterized gene within the 17p13 chromosomal region.

Mutations in a new photoreceptor-pineal gene on 17p cause Leber congenital amaurosis

Leber congenital amaurosis (LCA, MIM 204000) accounts for at least 5% of all inherited retinal disease and is the most severe inherited retinopathy with the earliest age of onset. Individuals affected with LCA are diagnosed at birth or in the first few months of life with severely impaired vision or blindness, nystagmus and an abnormal or flat electroretinogram (ERG). Mutations in GUCY2D (ref. 3), RPE65 (ref. 4) and CRX (ref. 5) are known to cause LCA, but one study identified disease-causing GUCY2D mutations in only 8 of 15 families whose LCA locus maps to 17p13.1 (ref. 3), suggesting another LCA locus might be located on 17p13.1. Confirming this prediction, the LCA in one Pakistani family mapped to 17p13.1, between D17S849 and D17S960-a region that excludes GUCY2D. The LCA in this family has been designated LCA4 (ref. 6). We describe here a new photoreceptor/pineal-expressed gene, AIPL1 (encoding aryl-hydrocarbon interacting protein-like 1), that maps within the LCA4 candidate region and whose protein contains three tetratricopeptide (TPR) motifs, consistent with nuclear transport or chaperone activity. A homozygous nonsense mutation at codon 278 is present in all affected members of the original LCA4 family. AIPL1 mutations may cause approximately 20% of recessive LCA, as disease-causing mutations were identified in 3 of 14 LCA families not tested previously for linkage.

African and Levantine origins of Pakistani YAP+ Y chromosomes

We surveyed 9 Pakistani subpopulations for variation on the nonrecombining portion of the Y chromosome. The polymorphic systems examined were the Y-chromosome Alu insertion polymorphism (YAP) at DYS287, 5 single nucleotide polymorphisms, and the tetranucleotide microsatellite DYS19. Y chromosomes carrying the YAP element (YAP+) were found in populations from southwestern Pakistan at frequencies ranging from 2% to 8%, whereas northeastern populations appeared to lack YAP+ chromosomes. In contrast to other South Asian populations, several Pakistani subpopulations had a high frequency of the DYS19*B allele, the most frequent allele in West Asian, North African, and European populations. The combination of alleles at all polymorphic sites gave rise to 9 YAP-DYS19 combination haplotypes in Pakistani populations, including YAP+ haplotypes 4-A, 4-B, 5-C, and 5-E. We hypothesize that the geographic distributions of YAP+ haplotypes 4 and 5 trace separate migratory routes to Pakistan: YAP+ haplotype 5 may have entered Pakistan from the Arabian Peninsula by means of migrations across the Gulf of Oman, whereas males possessing YAP+ haplotype 4 may have traveled over land from the Middle East. These inferences are consistent with ethnohistorical data suggesting that Pakistan's ethnic groups have been influenced by migrations from both African and Levantine source populations.

Phenotype of autosomal recessive congenital microphthalmia mapping to chromosome 14q32

BACKGROUND

Congenital microphthalmia (OMIM: 309700) may occur in isolation or in association with a variety of systemic malformations. Isolated microphthalmia may be inherited as an autosomal dominant, an autosomal recessive, or an X linked trait.

METHODS

Based on a whole genome linkage analysis, in a six generation consanguineous family with autosomal recessive inheritance, the first locus for isolated microphthalmia was mapped to chromosome 14q32. Eight members of this family underwent clinical examination to determine the nature of the microphthalmia phenotype associated with this locus.

RESULTS

All affected individuals in this family suffered from bilateral microphthalmia in association with anterior segment abnormalities, and the best visual acuity achieved was "perception of light". Corneal changes included partial or complete congenital sclerocornea, and the later development of corneal vascularisation and anterior staphyloma. Intraocular pressure, as measured by Schiotz tonometry, was greatly elevated in many cases.

CONCLUSIONS

This combination of ocular defects suggests an embryological disorder involving tissues derived from both the neuroectoderm and neural crest. Other families with defects in the microphthalmia gene located on 14q32 may have a similar ocular phenotype aiding their identification.

Connexin 50 mutation in a family with congenital "zonular nuclear" pulverulent cataract of Pakistani origin

Inherited cataract is a clinically and genetically heterogeneous disease that most often presents as a congenital autosomal dominant trait. Here we report linkage of a three-generation family of Pakistani origin with autosomal dominant cataract "zonular nuclear" pulverulent type (CZNP) on chromosome 1q21.1. Genome wide-linkage analysis excluded all the known cataract loci except on chromosome 1q. Significantly positive 2-point lod score values (Z=3.01 at theta=0) were obtained for markers D1S305 and D1S2721, which are known to flank the gene for connexin 50 (Cx50) or gap junction protein alpha-8 (Gja8). Previously a mutation in this gene has been reported in a British family with zonular pulverulent cataract (CZP). Here we describe a second mutation (E48K) in connexin 50 that confirms the involvement of this gene in cataractogenesis.

A locus for autosomal recessive congenital microphthalmia maps to chromosome 14q32

Congenital microphthalmia (CMIC) (OMIM 309700) may occur in isolation or in association with a variety of systemic malformations. Isolated CMIC may be inherited as an autosomal dominant, an autosomal recessive, or an X-linked trait. On the basis of a whole-genome linkage analysis, we have mapped the first locus for isolated CMIC, in a five-generation consanguineous family with autosomal recessive inheritance, to chromosome 14q32. All affected individuals in this family have bilateral CMIC. Linkage analysis gave a maximum two-point LOD score of 3.55 for the marker D14S65. Surrounding this marker is a region of homozygosity of 7.3 cM, between the markers D14S987 and D14S267, within which the disease gene is predicted to lie. The genes for several eye-specific transcription factors are located on human chromosome 14q and in the syntenic region of mouse chromosome 12. However, both CHX10 (14q24.3), mutations of which give rise to CMIC in mouse models, and OTX2 (14q21-22) can be excluded as candidates for autosomal recessive congenital microphthalmia (arCMIC), since they map outside the critical disease region defined by recombination events. This suggests that arCMIC is caused by defects in a novel developmental gene that may be important or even essential in eye development.

Cations in the didanosine tablet reduce ciprofloxacin bioavailability

The effect of the magnesium-aluminum cations contained in didanosine chewable tablets on ciprofloxacin pharmacokinetics was evaluated in 12 healthy volunteers. The study was designed as a randomized, balanced, open, two-period, two-treatment crossover trial with a 7-day washout period between treatments. In one phase, subjects received a single 750 mg ciprofloxacin tablet alone. In the didanosinecation regimen, subjects received two didanosine-placebo tablets every 12 hours for two doses. On day 2, they received two didanosine-placebo tablets immediately followed by a single 750 mg ciprofloxacin tablet. Serial blood samples were collected for 24 hours after administration of each ciprofloxacin dose. The average maximum concentration of ciprofloxacin alone was 3.38 +/- 0.63 (SD) micrograms/ml compared with 0.25 +/- 0.21 (SD) micrograms/ml when ciprofloxacin was administered with the didanosine placebo (p < 0.0001). The mean (+/- SD) area under the plasma drug concentration-time curve from time 0 to the last measurable concentration for ciprofloxacin alone was 15.50 +/- 2.69 micrograms.hr/ml compared with 0.26 +/- 0.21 micrograms.hr/ml when ciprofloxacin was coadministered with the didanosine-placebo (p < 0.0001). The mean time to maximum concentration of ciprofloxacin alone decreased from 1.56 +/- 0.62 to 0.75 +/- 0.38 hours with buffer administration (p = 0.0012). The simultaneous administration of ciprofloxacin and didanosine should be avoided.