Polycystic kidneys and del (4)(q21.1q21.3): further delineation of a distinct phenotype

A three year-old boy was evaluated because of growth and developmental delay, hypotonia and dysmorphic features. G-banding analysis revealed a small interstitial deletion of the long arm of chromosome four described as 46,XY,del (4)(q21.1q21.3). This patient's findings on physical exam included relative macrocephaly, frontal bossing, short fingers with clinodactyly and were consistent with the phenotypes of previously reported deletions involving the 4q21--> 4q22 band region (Am. J. Med. Genet. 68 (1997) 400-405). To date there are 10 reported live-born cases with such deletions and similar features. The case reported here delimits a minimal critical region for this phenotype to chromosomal region 4q21. Our patient was also found to have cysts in both his kidneys. The gene for type II polycystic kidney disease (PKD2) has been mapped to chromosomal region 4q21--> 4q23. FISH analysis, with a probe including the PKD2 gene, demonstrated hemizygosity at this locus. Thus the absence of one of the PKD2 alleles in the case reported here is associated with early bilateral cyst development. Kidney ultrasound/autopsy studies were reported in seven of the patients with the characteristic phenotype, and were positive for cysts in four cases including the one presented here (Clin. Genet. 31 (1987) 199-205; Am. J. Med. Genet. 68 (1997) 400-405; Am. J. Med. Genet. 40 (1991) 77-790. Our report supports the presence of a distinct phenotype associated with a deleted chromosomal region within 4q21. Hemizygosity for the PKD2 gene is likely in such deletions and may lead to renal cyst formation.

Sources of semiochemicals mediating host finding in Callosobruchus chinensis (Coleoptera: Bruchidae)

Bruchid pests such as Callosobruchus chinensis (Linnaeus) endanger stored legume seeds throughout the tropical belt. The chemical composition of the headspace volatiles from healthy and fourth instar larvae-infested cowpea seeds were identified, characterized, and compared using gas chromatography-mass spectrometry. Y-tube olfactometer bioassays were performed to evaluate the effect of these chemicals on the orientation of conspecific adult females. Analysis of volatiles released from healthy and infested seeds revealed qualitative differences for three out of the 17 compounds identified. Dimethyl disulphide, isobutenyl methyl ketone and methyl trisulphide were found only in the blend emitted from infested but not from healthy seeds. Quantitative differences were apparent for tridecane which was released in larger amounts from infested seeds. While volatiles collected from healthy seeds were attractive to female bruchids, volatiles collected from infested seeds were repellent. To test the hypothesis that the qualitative differences in the chemical composition found may be due to insect-derived components, the volatiles from frass and fourth instar larvae combined were analysed. These volatiles contained both of the sulphides emitted from infested seed but not from healthy seeds. Although a limited induction of volatiles from cowpea seeds cannot be excluded, it is postulated that behavioural differences of the female weevils are largely due to insect-derived semiochemicals. The potential use of such semiochemicals as part of an integrated pest management strategy is discussed.

[The signal-averaged ECG in long-term monitoring of patients with fulminant myocarditis]

A case of a 24 year-old patient with fulminant myocarditis is described. The lymphocytic myocarditis was proved by endocardial biopsy. The patient had been followed for 15 months clinically, by transthoracic ultrasound and by the signal averaged ECG. The clinical and ultrasound parameters of the left ventricular systolic dysfunction subsided within 6 months, STT changes on the routine 12-lead ECG within 2 months. On the signal-averaged ECG, changes were observed in both the time and in the frequency domain. When the results of the initial examination (6 weeks after the beginning of the disease) were compared with the examination at the 7th month of the disease there was a prolongation of the QRS duration (from 95 ms to 104 ms), prolongation of the duration of the filtered ECG below 40 microV (from 21.5 to 36.2 microV) and the decrease of the total sum of the potential in the terminal part of the QRS. Most apparent was the decrease in the total sum of the high-frequency components (filter 70-250 Hz) of the QRS (RMSt: from 53.3 microV to 37.9 microV at the same noise level). In contrast to the changes in the time domain parameters there was no tendency in improvement of the RMSt. In patients with myocarditis the signal averaged ECG may prove to be a suitable tool for the long-term follow-up of the subclinical structural abnormalities of the left ventricular wall.

[Dysfunction of a valve prosthesis]

The authors describe the case of a haemodynamically unstable patient with dysfunction of a valvular prosthesis which was resolved by emergency surgery. In the discussion they deal with two basic causes of these dysfunctions and their possible solutions.

Efficacy of crude extracts of Andrographis paniculata nees. on Callosobruchus chinensis L. during post harvest storage of cowpea

Bioefficacy of different solvent fractions of A. paniculata was tested against the cowpea weevil, C. chinensis in terms of its effect on adult mortality, total egg output and emergence of F1 adults. All the extracts were effective against the weevil, the efficacy was however more significant with respect to methanol and ethyl acetate extracts at the highest concentrations (1,000 ppm) which lead to 72.01 and 67.69% adult mortality respectively. The efficacy was dose dependent. Total egg and percent emergence of Fl adults were lowest for methanol followed by ethyl acetate fractions. Possible role of the principal chemical constituents of this plant in bringing about mortality of the pest, reduction in egg laying and adult emergence are discussed.

Evaluation of efficacy and safety of losartan potassium in the treatment of mild to moderate hypertension as compared to enalapril maleate

AIM

To study the effect of losartan potassium in the treatment of mild to moderate hypertension and to compare its efficacy and adverse effect profile with enalaparil maleate.

MATERIAL AND METHODS

One hundred and forty five patients with mild to moderate essential hypertension were enrolled in this randomized, double blind, controlled, parallel and multicentric study. Seventy two patients received losartan potassium 50 mg and seventy three received enalapril maleate 5 mg.

RESULTS

Losartan potassium reduced the DBP to < 90 mm Hg in 59% of the patients at the end of 8 weeks compared to 45% in the enalapril maleate group. DBP was reduced by 10 or > than 10 mm Hg in 89% of the patients with losartan as compared to the baseline whereas it was 80% in the enalapril group. Percentage of side effects seen in losartan and enalapril groups were 12 and 22 respectively.

CONCLUSION

Losartan potassium is an efficacious antihypertensive agent in mild to moderate hypertension. It also has fewer side effects when compared to enalapril maleate.

Prenatal diagnosis and outcome of mosaicism for a de novo unbalanced translocation identified in amniocytes

Mosaicism for an unbalanced reciprocal translocation was identified in cultured amniocytes of a 16-week-old fetus; mos46,XX,der(4)t(4;5)(q34;q12)/46,XX. Parental karyotypes were normal, indicating a de novo origin of the unbalanced translocation in the fetus. The additional chromosomal material on the der(4) was derived from chromosome 5 as demonstrated by both GTG banding and fluorescence in situ hybridization with a chromosome 5 paint. Two subsequent amniocenteses, at 18 and 20 weeks, confirmed the presence of the abnormal cell line. A percutaneous umbilical blood sample (PUBS) contained only normal cells, 46,XX, and a high resolution ultrasound revealed no fetal abnormalities or growth retardation. The pregnancy was continued and a normal female was born at term. No evidence of the unbalanced translocation cell line was found in cord blood or placental samples at birth. The finding of mosaicism for an unbalanced translocation at amniocentesis is rare, and is associated with a high risk of fetal abnormality. This case illustrates the importance of follow-up studies by PUBS and high-resolution ultrasound for further assessing the risk of phenotypic abnormality.

Homozygosity for pericentric inversions of chromosome 9. Prenatal diagnosis of two cases

The finding of homozygosity for a pericentric inversion of chromosome 9 [inv(9)] is rare, and previously has not been reported at prenatal diagnosis. We describe two unrelated cases of homozygosity for inv(9) identified in amniocytes. In each case, both parents were heterozygotes for the inv(9); 46,XX,inv(9)(p11q13) and 46,XY,inv(9) (p11q13). Case 1 resulted in a normal term infant who at age 5 years was phenotypically and developmentally normal. Case 2 was referred for severe intrauterine growth retardation (IUGR) and oligohydramnios, and subsequently expired in utero. Even though inv(9) is a normal chromosome variant with a frequency of 1 to 3% in the general population, the finding of homozygosity for inv(9) and IUGR in this fetus suggested the possibility of uniparental disomy (UPD). Molecular studies confirmed the presence of both parental inv(9) chromosomes, excluding the possibility of chromosome 9 UPD as the cause of IUGR in this fetus. Presumably, inv(9) homozygosity results from the high frequency of inv(9) heterozygosity, and is a normal variant. However, until the effects of UPD for chromosome 9 are established, parental karyo types and, where appropriate, molecular studies should be performed to exclude UPD. In addition, more reports of inv(9) homozygosity detected prenatally are needed to assess its frequency and outcome.

Prenatal diagnosis of a familial interchromosomal insertion of Y chromosome heterochromatin

An apparently unbalanced karyotype containing an abnormal chromosome 11 was identified in a 16-week female fetus by analysis of cultured amniocytes. Fluorescence in situ hybridization (FISH) with a chromosome 11 paint identified the presence of an insertion in band 11q24. Parental karyotyping documented an unbalanced karyotype with the same der(11) chromosome in the phenotypically normal father. CBG-banding and FISH identified the insertion to be Yq12 heterochromatin: 46,XY, der(11)ins(11;Y)(q24;q12q12).ish der(11) (wcp11+,DYZ1+). The same der(11) chromosome was also found in the phenotypically normal paternal grandmother, demonstrating this additional Y chromosomal material did not affect normal female sexual development or fertility. The parents elected to continue the pregnancy and a normal girl was born at term, further confirming that this rare familial variant has no clinical significance. This case illustrates the importance of family studies, appropriate banding, and FISH analyses to accurately characterize apparent chromosomal abnormalities.

Mosaicism for a small supernumerary ring X chromosome in a dysmorphic, growth-retarded male: mos47,XXY/48,XXY, +r(X)

Supernumerary ring X [r(X)] chromosomes are often found in patients with Turner syndrome. The phenotypic effects of the r(X) chromosome are variable, and largely depend on the presence or absence of the X inactivation (XIST) locus. Ring(X) chromosomes in males are rare and have been previously reported in only four cases, with 47,XY, + r(X) or mos47,XY, +r(X)/46,XY karyotypes. These patients all had developmental delay and dysmorphic features. We describe a 2.5-year-old male patient with facial dysmorphia, growth retardation, microcephaly, global developmental delay, and microphallus. Cytogenetic analysis from peripheral blood lymphocytes and fibroblasts identified mosaicism for two cell lines: mos48,XXY, + r(?X)/47,XXY. Fluorescence in situ hybridization (FISH) with an X chromosome paint showed the ring chromosome to be X chromosome derived. This is the first case of an r(X) chromosome described in a 47,XXY patient. FISH analysis of the r(X) chromosome with an XIST probe showed that the XIST locus was absent. Functional disomy of genes in the r(X) chromosome most likely accounts for the abnormal phenotype in the proband.

Prenatal detection and molecular characterization of a de novo duplication of the distal long arm of chromosome 19

A tandem duplication of the distal long arm of chromosome 19 was identified in a 10 week fetus by analysis of chorionic villi. The fetal karyotype from two primary cultures was 46,XY,dir dup(19)(q13.2q13.4). The origin of the extra material was confirmed by fluorescence in situ hybridization using a chromosome 19 whole chromosome probe. Parental chromosomes were normal, indicating a de novo origin of the extra chromosome material. This is the first case of dup(19q) detected by prenatal diagnosis. Molecular studies demonstrated that the duplication involved a maternal chromosome 19.

Characterization of a de novo unbalanced chromosome rearrangement by comparative genomic hybridization and fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) has proven useful for the identification of chromosomal material of unknown origin. More recently, comparative genomic hybridization (CGH) has been used to identify deletions and amplifications, particularly in neoplastic samples. Here, we describe the combined use of CGH and FISH to identify the origin of a de novo unbalanced translocation in a newborn with multiple congenital anomalies. GTG banding of metaphases from cultured lymphocytes showed an unbalanced karyotype, with extra material on a chromosome 5: 46,XX,add(5)(q35). Parental karyotypes were both normal. CGH revealed the additional material was from distal 11q (11q23-->'qter). This finding was confirmed by FISH with a whole chromosome paint for chromosome 11. Based on the CGH and FISH analyses, the proband's karyotype was therefore 46,XX,der(5)t(5;11)(q35.2; q23.2).ish der(5)(wcp11+). This case demonstrates the efficient use of CGH and confirmatory FISH for the identification of chromosomal material of unknown origin.

Prenatal diagnosis of a fetus with two balanced de novo chromosome rearrangements

Two apparently balanced chromosome rearrangements were identified in a 17-week fetus by analysis of cultured amniocytes. The fetal karyotype was 46,XX,t(2;16) (q33;q24), inv(7)(p15q11.23). Parental karyotypes were normal, indicating a de novo origin of both chromosome rearrangements in the fetus. The risk of phenotypic abnormality from a de novo reciprocal translocation of inversion has been estimated at approximately 7% [Warburton, 1991]. The risk of abnormality in this fetus was estimated to be a minimum of 14%, based on the additive risk of each rearrangement, equivalent to 3.5% per chromosome breakpoint. The pregnancy was terminated because of the risk of abnormality and the detection of intrauterine growth retardation by ultrasound. In the absence of additional experience, the minimum presumed risk of phenotypic abnormality for de novo, multiple or complex chromosome rearrangements identified prenatally may be estimated as the additive risk of the number of chromosome breakpoints involved.

Epidemiology of symptomatic human rotaviruses in Bangalore and Mysore, India, from 1988 to 1994 as determined by electropherotype, subgroup and serotype analysis

Epidemiology of symptomatic rotaviruses from Bangalore and Mysore in Southern India was investigated. While serotype G3 predominated throughout the 7-year study period from 1988 to 1994 in Bangalore, serotype G1 was more predominant than serotype G3 in Mysore during 1993 and 1994. Serotype G2 strains were either not detected or infrequently observed in both the cities. However, several strains with subgroup I and 'short' RNA pattern that exhibited high reactivity with typing MAbs specific for serotype 2 as well as other serotypes were detected throughout the period. Among the nonserotypeable strains from both cities, several exhibited dual subgroup (SGI + II) or subgroup I specificity and 'long' RNA pattern indicating their probable animal origin. Notably, a gradual, yet highly significant reduction in rotavirus gastroenteritis, from 45.3% in 1988 to 1.8% during 1994, was observed in Bangalore in stark contrast to the consistently high (about 34%) incidence of asymptomatic infections among neonates by I321-like G10P11 type strains during the same period. Moreover, I321-like asymptomatic strains were not detected in children with diarrhea.

Critical minimum length of the central helix in troponin C for the Ca2+ switch in muscular contraction

In the troponin C (TnC) dumbbell, the NH2- and COOH-terminal lobes are well delineated, but the role of the central helix and especially the function of its long length remain doubtful. To study this, we used a cDNA construct encoding rabbit fast-twitch muscle TnC, comprising multiple restriction sequences to facilitate mutagenesis (Babu, A., Su, H., Ryu, Y. & Gulati, J. (1992) J. Biol. Chem. 267, 15469-15474). Systematically, we have deleted 3-12 amino acid residues from the central helix and examined their effects in maximally activated skinned muscle fibers. Limiting the deletions to 7 amino acid residues manifested little change in maximal force development (Sheng, Z., Francois, J. M., Hitchcock, S. E. & Potter, J. D. (1991) J. Biol. Chem. 266, 5711-5715). However, with further deletions, we now find that contractility was inhibited pari passu; by 12 deletions, the inhibition was complete. The critical minimum length for the central helix is thereby estimated as 27 A. The Ca2+ binding capacity (4 mol of Ca2+/mol of protein) as well as the structural characteristics (alpha-helicity by CD measurements and the fluorescence emitted by Tyr-109) indicated a well preserved global conformation of the short mutant. However, surprisingly, two of these short mutants filled each TnC slot under highly specific superloading conditions: one short molecule was taken up in EGTA solution, and the second molecule was captured and retained with Ca2+. They also rescued the contractile switch, evidently in a bimolecular reaction. Another short variant (putative skeletal fast muscle TnC-I-II), in which the NH2-terminal Ca(2+)-binding sites were incapacitated, failed to respond to superloading, indicating that sites III and IV could not substitute for sites I and II. The results suggest that a critical role of the central helix linker in TnC is to keep the two lobes optimally apart, evidently in proximity of their respective target sites on troponin I in the fiber.

Identification of the regions conferring calmodulin-like properties to troponin C

The structural and functional correlations between troponin C (TnC) and calmodulin (CaM) were investigated by mutagenizing a synthetic cDNA coding rabbit skeletal muscle TnC. Compared with TnC, calmodulin lacks the N-terminal alpha-helical arm (N-helix), and its central helix is shorter due to the absence of 88KGK90 residues. Deleting both regions concomitantly (delta Nt delta KGK) elicited CaM-like regulation as tested (i) by smooth muscle contractility (maximal tension = 80 +/- 5% Po of control) and (ii) by the activation of phosphodiesterase (Vmax = 75 +/- 2% of control). The Ca(2+)-binding capacity of the mutant and the effect of the mutant on maximally Ca(2+)-activated tension of skinned rabbit psoas muscle fibers were both conserved. Furthermore, in the linker region of the central helix, replacing the TnC-characteristic 85EDAKGK90 successive residues with CaM-specific DTD residues generated a highly effective CaM mimic (Vmax = 96 +/- 2%) whether or not the N-helix was also retained. Apparent KD values (i.e. concentrations for half-maximal response) for the successful mutants were similar to each other but about 200-fold higher than that for CaM. A part of the alpha-helical linker region in CaM may unfold and bend to promote multiplicity of target interaction using all four hands (Ikura, M., Clore, G. M., Gronenborn, A. M., Zhu, G., Klee, C. B., and Bax, A. (1992) Science 256, 632-638; Meador, W. E., Means, A. R., and Quiocho, F. A. (1992) Science 257, 1251-1255). In contrast, our results suggest that the TnC central helix evolved to be less pliable by the combined influences of 85EDAKGK90 residues and the alpha-helical extension in N terminus, thereby keeping the N-terminal hands well separated from their C-terminal counterparts.