Detection of multidrug-resistant Salmonella typhimurium DT104 by multiplex polymerase chain reaction

Salmonella typhimurium definitive type 104 (DT104) is a virulent pathogen for humans and animals with many strains having multiple drug resistance characteristics. The organism typically carries resistance to ampicillin, chloramphenicol, florfenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT-resistant). A multiplex PCR method was developed to simultaneously amplify four genes, florfenicol (flo(st)), virulence (spvC), invasion (invA), and integron (int) from S. typhimurium DT104 (ACSSuT-type). Twenty-two ACSSuT-resistant DT104 isolates in our collection gave 100% positive reactions to this PCR assay by amplifying 584-, 392-, 321- and 265-bp PCR products, using primers specific to the respective target genes. One Salmonella strain DT23, ACSSuT-resistant, phage type 711 failed to amplify the 584-bp fragment, indicating that this method is specific for DT104-type ACSSuT-resistant S. typhimurium strains. One clinical and one bovine ASSuT-resistant strains that were sensitive to chloramphenicol and florfenicol did not yield a 584-bp fragment, indicating the absence of the flo(st) gene. This method will be useful for rapid identification of ACSSuT-type DT104 strains from clinical, food and environmental samples.

The use of intra aortic baloon pump in patients undergoing coronary artery bypass grafting at the Aga Khan University Hospital, Karachi

OBJECTIVE

To review the experience in the use of Intra Aortic Balloon Pump (IABP) in patients undergoing Coronary Artery Bypass Grafting (CABG) at a tertiary care hospital with a new Open Heart surgery program.

DESIGN

Retrospective study.

SETTING

The Aga Khan University Hospital, Karachi.

PATIENTS

Medical records of all patients undergoing CABG between November 1994 and July 1997 were reviewed and those in whom IABP device was used, were included in this study.

RESULTS

A total of 15 patients had IABP support during the study period. Four surgeries were done urgently while two were emergencies. There were three mortalities. Ejection fractions in all but one patient were impaired. Among the surviving patients, the average pre-IABP Cardiac Index was 2.6 litres/min/meter2 which registered an average increase of 21.15% after the initiation of the IABP. The Pulmonary Artery Wedge Pressure also showed an average reduction of 29.11% from the pre IABP levels reflecting an increase in the cardiac output with the use of the IABP.

CONCLUSION

This series represents the early experience of a new cardiac surgery center in Pakistan in the use of IABP. Although the numbers in this study are too small to derive any conclusions, the overall morbidity and mortality in this short series are within acceptable limits in the high risk patients included.

Care of the elderly: Parallel Thinking

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Ethylene glycol exposures managed by the ASPCA National Animal Poison Control Center from July 1995 to December 1997

Five-hundred and ten cases of ethylene glycol (EG) exposures in animals were compiled by the ASPCA National Animal Poison Control Center from July 1995 through December 1997. Case distribution was analyzed by species, sex, age, weight, seasonality, treatment intervention and final outcome. Dogs and cats were most commonly involved (98.0%). The sex distribution was approximately equal. Adult animals accounted for the majority of cases. Exposures were commonly (57.0%) from container spill, engine flush, or engine leak and were in or around the home (66.0%). Cases were reported throughout the year with slight increase during March-May. Among cases with a known final outcome, 59.0% did not show clinical signs and death/euthanasia, major and minor illness was reported in 28.0%, 5.0% and 8.0%. In view of the widespread use and potential toxicity of EG, the low number of EG exposures reported (510) among the total number of hazardous exposures (97,383) to all substances for the same period was remarkable. The EG exposures resulting in animal death/euthanasia were lower than previously published.

Muir-Torre syndrome: case report of a patient with concurrent jejunal and ureteral cancer and a review of the literature

BACKGROUND

Muir-Torre syndrome is a rare autosomal dominant genodermatosis, first described in 1967, characterized by the presence of sebaceous tumors and an internal malignancy in the absence of other predisposing factors.

OBJECTIVE

Our purpose was to review and update published literature on Muir-Torre syndrome.

METHODS

We describe a 66-year-old white man with a history of sebaceous tumors and newly diagnosed transitional cell cancer of the right ureter and adenocarcinoma of the jejunum. The literature on Muir-Torre syndrome is reviewed by means of MEDLINE search and available published reports and updated.

RESULTS

Only 205 cases of Muir-Torre syndrome with 399 internal malignancies have been reported. The common presentation is the presence of sebaceous tumors along with a low-grade visceral malignancy. Sebaceous tumors appeared before the internal malignancy in 45 cases (22%), concurrently in 12 (6%), and after the internal malignancy in 114 (56%). In 33 (16%) of 205 patients, a temporal relationship was not reported. The total number of sebaceous gland carcinomas reported is 44; 17 of 44 were neoplasms of the meibomian gland. Keratoacanthomas have been noted in 48 (23%) of 205 patients. Gastrointestinal cancers are the most common internal malignancies (61%), followed by genitourinary (22%).

CONCLUSION

The presence of sebaceous tumors warrants a search for an internal malignancy. In patients with Muir-Torre syndrome, regular follow-up and search for new malignancy is mandatory. Evaluation and monitoring of the family members of patients are also necessary. Patients and their families should be counseled for genetic testing. Genetic analysis of the primary tumor and skin lesions should be arranged as an added research tool if possible to better understand the disease.

Estrogen receptor variants ERdelta5 and ERdelta7 down-regulate wild-type estrogen receptor activity

The estrogen receptor (ER) plays a key role in mediating the effect of estrogens. It is the primary target for endocrine therapy for many diseases, including breast cancer. The ER contains six domains that are associated with distinct functions; the presence of all six domains is required for ligand-dependent receptor activity. ER variants, reported in breast tumors and other neoplasms, usually lack one or more domains or a part of a domain. Such deletions can have dramatic effects on ER activity, cellular response to hormone, and response to hormonal therapy. We used simple and rapid yeast systems to understand more clearly how ER variants alter the response of wild-type ER (wtER) to estrogen and antiestrogens. We co-expressed ER variant, ERdelta5 or ERdelta7, with wtER in yeast containing an ERE-LacZ reporter. We found that ERdelta5 and ERdelta7 decreased the response of wtER to 1 nM 17beta-estradiol by 41-43 and 24-34%, respectively. Alone, ERdelta5 displayed weak hormone-independent transcriptional activity that was not affected by tamoxifen or ICI 182,780. ERdelta7, in contrast, showed no constitutive activity and no response to ligands. To further understand whether ERdelta5 and ERdelta7 affect wtER activity by forming a variant:wtER heterodimer, we used the yeast two-hybrid system. The protein-protein interaction results showed that ERdelta5 and ERdelta7 could form neither homodimers with themselves nor heterodimers with wtER. This finding suggests that the influence of ERdelta5 and ERdelta7 on wtER is not mediated by suppressing wtER through heterodimerization.

Simultaneous detection of erythromycin-resistant methylase genes ermA and ermC from Staphylococcus spp. by multiplex-PCR

A comparative analysis of the two most dominant erythromycin-resistance determinant genes in Staphylococcus sppnamely, the ermA and ermC genes, was carried out. Sixty erythromycin-resistant strains of Staphylococcus spp. were tested, of which 24 were avian and 36 were clinical isolates. Our results indicated the prevalence of ermA over the ermC gene as opposed to the widely held opinion of the ermC gene being the most dominant resistance determinant gene. A multiplex-PCR assay was developed to detect the presence of ermA and ermC genes. Two pairs of primers, specific for the detection of ermA and ermC genes, were used in a multiplex-polymerase chain reaction (PCR) assay to yield amplified DNA products of 610 and 520 bp, respectively. Their digestion with restriction enzyme FokI that yielded a 477 bp and a 132 bp digestion product for ermA and a 333 bp and a 187 bp digestion product for ermC confirmed the authenticity of PCR products. The method could be used to amplify the ermA and ermC genes with as little as 5 pg of template DNA. The use of excess primers or the template DNA resulted in gene-specific amplification and no non-specific amplification was observed by changing the primer to primer or template to primer ratios. Furthermore, no amplification from erythromycin-sensitive S. aureus strain was observed. Using this assay, the poultry strains were found to contain either ermA alone (50%) or a combination of ermA (100%) and ermC (50%) both. The clinical strains contained either ermA (94.5%) or ermC (5.5%) but never both. The gene-specific internal probes were also used to verify the above findings and a high degree of correlation between the multiplex PCR and Southern hybridization data was observed.

The normal breast epithelium of women with breast cancer displays an aberrant response to estradiol

Breast epithelial response to estradiol may play an important role in breast cancer etiology. We have examined the relationship between serum estradiol and progesterone levels and normal breast epithelial expression of estrogen receptor (ER) alpha, progesterone receptor (PgR), and epithelial proliferation (as reflected by the Ki-67 labeling index) in 121 women (50 newly diagnosed breast cancer cases and 71 benign breast disease controls). Simultaneous samples of grossly normal breast tissue and venous blood were obtained from women undergoing breast surgery. Serum estradiol and progesterone levels were measured by radioimmunoassay; breast epithelial ER, PgR, and Ki-67 expression was measured by immunohistochemistry. Linear regression, controlled for patient age and ductal and lobular composition of the tissue, showed that the breast epithelium of control women displayed an inverse correlation between serum estradiol and ER-alpha, which was not seen in case women (P for the difference in regression slopes = 0.001). PgR expression displayed a significant positive correlation with serum estradiol in cases, but not in controls. Epithelial proliferation had no relationship to either estradiol or progesterone in both cases and controls but showed an inverse relationship with ER in controls and a direct relationship in cases (P for the difference in regression slopes = 0.066). These results suggest a dysregulation of hormonal response in the normal breast epithelium of high-risk women, with lack of regulation of ER by estradiol, increased estrogen responsiveness as reflected by PgR expression, and a dissociation of ER expression and proliferative response.

Prevalence of utilization of native medicine among primary care consumers

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Biochemical and molecular characterization of erthromycin-resistant avian Staphylococcus spp. isolated from chickens

The epidemiology of the two common erythromycin-resistant methylase (erm) genes ermC and ermA was analyzed in 12 coagulase-negative Staphylococcus spp. and 34 coagulase-positive Staphylococcus spp. isolated from chicken. Southern hybridization indicated that only 2 of the 12 coagulase-negative Staphylococcus spp. strains contained the ermC gene on the plasmid; 1 strain of Staphylococcus xylosus harbored the ermC gene on a 2.5-kb plasmid, and 1 strain of Staphylococcus cohnii harbored the gene on a 4.0-kb plasmid. Twelve of the 34 strains of Staphylococcus aureus contained the ermC gene. Eleven of these strains had the ermC gene on a 2.5-kb plasmid, and 1 strain had the gene on a 4.0-kb plasmid. Ten of the 12 coagulase-negative Staphylococcus spp. and 22 of the 34 coagulase-positive Staphylococcus spp. harbored the ermA gene exclusively on the chromosome. Two different ermA EcoRI restriction fragment length polymorphisms (RFLP) were identified. A majority of the isolates was found to have two chromosomal inserts (8.0- and 6.2-kb EcoRI fragments) of ermA. One strain of S. aureus had different chromosomal inserts (6.4- and 5.8-kb EcoRI fragments) of ermA. Our results indicate that either the ermC or ermA gene, homologous to those described in human isolates, was present in all avian Staphylococcus spp. and that ermA was the predominant gene in coagulase-negative and coagulase-positive avian Staphylococcus spp. The size and copy numbers of the ermA gene were different from its human counterpart.

Characterization of a single-strand origin, ssoU, required for broad host range replication of rolling-circle plasmids

Single-stranded DNA (ssDNA) promoters are the key components of the single-strand origins (ssos) of replication of rolling-circle (RC) replicating plasmids. The recognition of this origin by the host RNA polymerase and the synthesis of a short primer RNA are critical for initiation of lagging-strand synthesis. This step is thought to be a limiting factor for the establishment of RC plasmids in a broad range of bacteria, because most of the ssos described are fully active only in their natural hosts. A special type of sso, the ssoU, is unique in the sense that it can be efficiently recognized in a number of different Gram-positive hosts. We have experimentally deduced the folded structure and characterized the ssDNA promoter present within the ssoU using P1 nuclease digestion and DNase I protection assays with the Bacillus subtilis and Staphylococcus aureus RNA polymerases. We have also identified the RNA products synthesized from this ssDNA promoter and mapped the initiation points of lagging-strand synthesis in vivo from ssoU-containing plasmids. Through gel mobility shift experiments, we have found that ssDNA containing the ssoU sequence can efficiently interact with the RNA polymerase from two different Gram-positive bacteria, S. aureus and B. subtilis. We have also realigned the narrow and broad host range sso sequences of RC plasmids, and found that they contain significant homology. Our data support the notion that the strength of the RNA polymerase-ssoU interaction may be the critical factor that confers the ability on the ssoU to be fully functional in a broad range of bacteria.

Is pulse pressure useful in predicting risk for coronary heart Disease? The Framingham heart study

BACKGROUND

Current definitions of hypertension are based on levels of systolic blood pressure (SBP) and diastolic blood pressure (DBP), but not on pulse pressure (PP). We examined whether PP adds useful information for predicting coronary heart disease (CHD) in the population-based Framingham Heart Study.

METHODS AND RESULTS

We studied 1924 men and women between 50 and 79 years of age at baseline with no clinical evidence of CHD and not taking antihypertensive drug therapy. Cox regression, adjusted for age, sex, and other risk factors, was used to assess the relations between blood pressure components and CHD risk over a 20-year follow-up. The association with CHD risk was positive for SBP, DBP, and PP, considering each pressure individually; of the 3, PP yielded the largest chi(2) statistic. When SBP and DBP were jointly entered into the multivariable model, the association with CHD risk was positive for SBP (HR, 1.22; 95% CI, 1.15 to 1.30) and negative for DBP (HR, 0. 86; 95% CI, 0.75 to 0.98). Four subgroups were defined according to SBP levels (<120, 120 to 139, 140 to 159, and >/=160 mm Hg). Within each subgroup, the association with CHD risk was negative for DBP and positive for PP. A cross-classification of SBP-DBP levels confirmed these results.

CONCLUSIONS

In the middle-aged and elderly, CHD risk increased with lower DBP at any level of SBP>/=120 mm Hg, suggesting that higher PP was an important component of risk. Neither SBP nor DBP was superior to PP in predicting CHD risk.

Regulation of DNA synthesis in Leydig cells obtained from neonatal pig testes

Three distinct waves of Leydig cell development are found in the pig testes, which occur during fetal, perinatal, and prepubertal periods. Proliferation of Leydig cells is primarily regulated by luteinizing hormone (LH); however, effects of LH on proliferation of immature rat Leydig cells are mediated by specific growth factors and cytokines such as transforming growth factor-alpha (TGFalpha), insulin-like growth factor-1 (IGF-1), interleukin-1beta (IL-1beta), steroidogenesis-inducing protein (SIP), and TGFbeta. The objective of the present study was to identify growth factors that could possibly be involved in the proliferation of Leydig cells in the neonatal pig testis. Leydig cells were isolated from 3- to 5-d-old pig testes, cultured for 48 hr in serum-free media, washed, and treated with hCG and/or IGF-1, epidermal growth factor (EGF), IL-1beta, SIP, and TGFbeta for 18 hr. Tritiated thymidine incorporation into DNA was assessed over a subsequent 4-hr period. Incorporation of [3H]-thymidine was stimulated by hCG treatment with a 2.3-fold increase over control cultures. SIP also induced a significant increase (P < 0.0001) in the incorporation of [3H]thymidine into Leydig cell DNA. Similarly, EGF and IGF-1 also increased DNA synthesis in neonatal porcine Leydig cells, whereas IL-1beta had no effect. TGFbeta had very little, if any, effect on DNA synthesis when added alone, but inhibited the stimulatory effects of other mitogens (SIP, hCG, EGF/TGFalpha, and IGF-1). Our results indicate that these growth factors may play a role in the LH/hCG-dependent proliferation of Leydig cells during the perinatal period of development.

Progesterone withdrawal and RU-486 treatment stimulate apoptosis in specific uterine decidual cells

Progesterone secretion is required for the growth and differentiation of endometrial stromal cells to form decidual cells. For many cells where a growth factor supports cell growth and proliferation, withdrawal of the growth factor initiates apoptosis. This study determined the time course and tissue location of apoptosis in deciduomal tissue after withdrawal of progesterone or injection of the antiprogestin, RU-486. Total DNA was isolated from decidual tissues at intervals after experimental treatments and separated electrophoretically. Internucleosomal DNA fragmentation characteristic of apoptosis was measured by quantitating levels of the 200 bp fragment. Apoptotic cells in tissue sections were detected by direct immunoperoxidase detection of digoxigenin-labeled DNA. Decidual apoptosis reached maximal levels at 12 h after withdrawal of progesterone or injection of RU-486. Increased concentrations of apoptotic cells were observed at the periphery of the growing deciduoma and in the antimesometrial deciduoma near the luminal epithelium after both treatments. These results suggest the withdrawal of progestin initiates apoptosis in cells at the early stages of decidualization.

Lymphatic filariasis in two distinct communities of upper Assam

Current status of bancroftian filariasis among two distinct communities of Upper Assam was evaluated. High prevalence (10.3% mf rate) in tea workers descendents of tribals migrated from endemic states such as Orissa, Bengal, Uttar Pradesh and southern states of India, were recorded. Among non tea workers (indigenous population) significantly low mf rate was found in spite of the fact that both the communities are living in close vicinity and in similar ecological and mosquitogenic conditions. Culex quinquefasciatus was incriminated as vector in the areas of both the communities. A group of recent migrants of Bihar and Bengal living in the locality of non tea worker population were also found microfilaraemic. Significantly lower infection rate in non tea worker population appears to be associated with host susceptibility to the infection. Familial clustering in microfilaraemic subjects noticed in tea workers group also suggests involvement of racial susceptibility to infection.

Direct in-gel hybridization of digoxigenin-labelled non-radioactive probes

An improved, simple, cost-effective and non-radioactive procedure for in-gel hybridization is described for the detection of signal in dried agarose gels. Large and small digoxigenin-labelled DNA and oligonucleotide probes hybridized efficiently and specifically with the complementary DNA sequences in the gel. The signal-to-noise ratios for the gels dried at 55 degrees C at 1 atmospheric pressure were 3-3.5-fold higher than the gels dried at 25 degrees C under vacuum. The method shows an increased sensitivity over currently available non-radioactive methods for in-gel hybridization. A single copy of a gene insert could be detected by the use of this procedure.

DNA replication specificity and functional E2 interaction of the E1 proteins of human papillomavirus types 1a and 18 are determined by their carboxyl-terminal halves

Replication of most papillomaviruses (PVs) requires the viral-encoded E1 and E2 proteins that bind to the origin of replication (ori) containing the E1- and E2-binding sites and help recruit host replication factors during the initiation of DNA replication. We studied the ability of heterologous E1 and E2 proteins to interact in vivo and support replication, using the human papillomavirus (HPV) types 1a and 18 as model systems. The E1 protein of HPV-1a in combination with HPV-18 E2 supported high-level replication of various ori plasmids. In contrast, the HPV-18 E1 protein interacted weakly with HPV-1a E2 during the replication of ori plasmids. We have previously shown that the E1 protein of HPV-1a alone is sufficient for replication of HPV-1a ori plasmids, whereas HPV-18 replication requires both the E1 and E2 proteins. However, in the latter case, E2-binding sites alone in the absence of the E1-binding site can function as the minimal ori. Based on the above observations, we generated hybrids between HPV-1a and HPV-18 E1 proteins in an effort to identify their "replication specificity" domains using a transient replication assay. These hybrids were also used to localize the domains in the E1 proteins that are involved in their functional interaction with the E2 protein during replication. Our results suggest that the "replication specificity" and functional E2 interaction domains of the HPV-1a and HPV-18 E1 proteins are located in their carboxyl-terminal halves.